WorldWideScience

Sample records for aerosol particles originating

  1. Spontaneous Aerosol Ejection: Origin of Inorganic Particles in Biomass Pyrolysis.

    Science.gov (United States)

    Teixeira, Andrew R; Gantt, Rachel; Joseph, Kristeen E; Maduskar, Saurabh; Paulsen, Alex D; Krumm, Christoph; Zhu, Cheng; Dauenhauer, Paul J

    2016-06-08

    At high thermal flux and temperatures of approximately 500 °C, lignocellulosic biomass transforms to a reactive liquid intermediate before evaporating to condensable bio-oil for downstream upgrading to renewable fuels and chemicals. However, the existence of a fraction of nonvolatile compounds in condensed bio-oil diminishes the product quality and, in the case of inorganic materials, catalyzes undesirable aging reactions within bio-oil. In this study, ablative pyrolysis of crystalline cellulose was evaluated, with and without doped calcium, for the generation of inorganic-transporting aerosols by reactive boiling ejection from liquid intermediate cellulose. Aerosols were characterized by laser diffraction light scattering, inductively coupled plasma spectroscopy, and high-speed photography. Pyrolysis product fractionation revealed that approximately 3 % of the initial feed (both organic and inorganic) was transported to the gas phase as aerosols. Large bubble-to-aerosol size ratios and visualization of significant late-time ejections in the pyrolyzing cellulose suggest the formation of film bubbles in addition to the previously discovered jet formation mechanism.

  2. Identification of origin of single aerosol particles using polycapillary X-ray lens

    Energy Technology Data Exchange (ETDEWEB)

    Sun Tianxi [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: stxbeijing@163.com; Liu Zhiguo; Zhu Guanghua; Liu Hui [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xu Qing [Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039 (China); Li Yude; Wang Guangpu; Sun Hongbo; Luo Ping; Pan Qiuli; Ding Xunliang [The Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2009-01-15

    A micro X-ray fluorescence (Micro-XRF) spectrometer based on a polycapillary focusing X-ray lens (PFXRL) and a laboratory X-ray source was designed to carry out the XRF analysis of single aerosol particles. The minimum detection limit (MDL) of this Micro-XRF spectrometer was 9 ppm for the Fe-K{alpha}. The percentage of the particles of vehicle exhaust among aerosol particles was studied in Beijing, Chinese capital, during the test of odd-even driving restrictions for Beijing 2008 Olympics Games. This Micro-XRF spectrometer had potential applications in the analysis of single aerosol particles.

  3. Primary and secondary organic aerosol origin by combined gas-particle phase source apportionment

    Directory of Open Access Journals (Sweden)

    M. Crippa

    2013-08-01

    Full Text Available Secondary organic aerosol (SOA, a prominent fraction of particulate organic mass (OA, remains poorly constrained. Its formation involves several unknown precursors, formation and evolution pathways and multiple natural and anthropogenic sources. Here a combined gas-particle phase source apportionment is applied to wintertime and summertime data collected in the megacity of Paris in order to investigate SOA origin during both seasons. This was possible by combining the information provided by an aerosol mass spectrometer (AMS and a proton transfer reaction mass spectrometer (PTR-MS. A better constrained apportionment of primary OA (POA sources is also achieved using this methodology, making use of gas-phase tracers. These tracers made possible the discrimination between biogenic and continental/anthropogenic sources of SOA. We found that continental SOA was dominant during both seasons (24–50% of total OA, while contributions from photochemistry-driven SOA (9% of total OA and marine emissions (13% of total OA were also observed during summertime. A semi-volatile nighttime component was also identified (up to 18% of total OA during wintertime. This approach was successfully applied here and implemented in a new source apportionment toolkit.

  4. Seasonality of new particle formation in Vienna, Austria - Influence of air mass origin and aerosol chemical composition

    Science.gov (United States)

    Wonaschütz, Anna; Demattio, Anselm; Wagner, Robert; Burkart, Julia; Zíková, Naděžda; Vodička, Petr; Ludwig, Wolfgang; Steiner, Gerhard; Schwarz, Jaroslav; Hitzenberger, Regina

    2015-10-01

    The impact of air mass origin and season on aerosol chemical composition and new particle formation and growth events (NPF events) in Vienna, Austria, is investigated using impactor samples from short-term campaigns and two long-term number size distribution datasets. The results suggest that air mass origin is most important for bulk PM concentrations, chemical composition of the coarse fraction (>1.5 μm) and the mass size distribution, and less important for chemical composition of the fine fraction (<1.5 μm). Continental air masses (crustal elements) were distinguished from air masses of marine origin (traces of sea salt). NPF events were most frequent in summer (22% of measurement days), and least frequent in winter (3% of measurement days). They were associated with above-average solar radiation and ozone concentrations, but were largely independent of PM2.5. Air mass origin was a secondary influence on NPF, largely through its association with meteorological conditions. Neither a strong dependence on the PM2.5 loading of the air masses, nor indications of a source area for NPF precursors outside the city were found.

  5. Characterisation of solid particles emitted from diesel and petrol engines as a contribution to the determination of the origin of carbonaceous particles in urban aerosol

    Science.gov (United States)

    Michalik, M.; Brzeżański, M.; Wilczyńska-Michalik, W.; Fisior, K.; Klimas, B.; Samek, L.; Pietras, B.

    2016-09-01

    Solid particles emitted from diesel and petrol engines were studied using a scanning electron microscope fitted with an energy dispersive spectrometer. The soot emitted from different engines under different operating conditions differed in particle size, and the form and size of aggregates. Identification of the soot particles emitted from diesel or petrol engines in urban aerosol based on their size and morphology was found to be impossible.

  6. Origin of aerosol particles in the mid latitude and subtropical upper troposphere and lowermost stratosphere from cluster analysis of CARIBIC data

    Directory of Open Access Journals (Sweden)

    M. Köppe

    2009-06-01

    Full Text Available The origin of aerosol particles in the upper troposphere and lowermost stratosphere over the Eurasian continent was investigated by applying cluster analysis methods to in situ measured data. Number concentrations of submicrometer aerosol particles and trace gas mixing ratios derived by the CARIBIC (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container measurement system on flights between Germany and South-East Asia were used for this analysis. Four cluster analysis methods were applied to a test data set and their capability of separating the data points into scientifically reasonable clusters was assessed. The best method was applied to seasonal data subsets for summer and winter resulting in five cluster or air mass types: stratosphere, tropopause, free troposphere, high clouds, and boundary layer influenced. Other source clusters, like aircraft emissions could not be resolved in the present data set with the used methods. While the cluster separation works satisfactory well for the summer data, in winter interpretation is more difficult, which is attributed to either different vertical transport pathways or different chemical lifetimes in the two seasons. The geographical distribution of the clusters together with histograms for nucleation and Aitken mode particles within each cluster are presented. Aitken mode particle number concentrations show a clear vertical gradient with the lowest values in the lowermost stratosphere (750–2820 particles/cm3 STP, minimum of the two 25%- and maximum of the two 75%-percentiles of both seasons and the highest values for the boundary-layer-influenced air (4290–22 760 particles/cm3 STP. Nucleation mode particles are also highest in the boundary-layer-influenced air (1260–29 500 particles/cm3 STP, but are lowest in the free troposphere (0–450 particles/cm3 STP. The given submicrometer particle number concentrations represent the

  7. Wind reduction by aerosol particles

    Science.gov (United States)

    Jacobson, Mark Z.; Kaufman, Yoram J.

    2006-12-01

    Aerosol particles are known to affect radiation, temperatures, stability, clouds, and precipitation, but their effects on spatially-distributed wind speed have not been examined to date. Here, it is found that aerosol particles, directly and through their enhancement of clouds, may reduce near-surface wind speeds below them by up to 8% locally. This reduction may explain a portion of observed ``disappearing winds'' in China, and it decreases the energy available for wind-turbine electricity. In California, slower winds reduce emissions of wind-driven soil dust and sea spray. Slower winds and cooler surface temperatures also reduce moisture advection and evaporation. These factors, along with the second indirect aerosol effect, may reduce California precipitation by 2-5%, contributing to a strain on water supply.

  8. AEROSOL PARTICLE COLLECTOR DESIGN STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Richard Dimenna, R

    2007-09-27

    A computational evaluation of a particle collector design was performed to evaluate the behavior of aerosol particles in a fast flowing gas stream. The objective of the work was to improve the collection efficiency of the device while maintaining a minimum specified air throughput, nominal collector size, and minimal power requirements. The impact of a range of parameters was considered subject to constraints on gas flow rate, overall collector dimensions, and power limitations. Potential improvements were identified, some of which have already been implemented. Other more complex changes were identified and are described here for further consideration. In addition, fruitful areas for further study are proposed.

  9. Characterization of PM2.5 particles originating from a modern waste incineration plant by factor analysis of chemical data, mass and black carbon in ambient aerosol

    DEFF Research Database (Denmark)

    Aboh, Innocent Joy Kwame; Henrikson, Dag; Laursen, Jens

    contribute to PM2.5 in urban air. Thus, the general problem is to characterise and identify the particle pollution, which can be attributed to gases and/or particles emitted by the waste incineration plant. For this reason aerosol samples, PM2.5, were collected and analyzed for concentrations of twenty...... are subject to restrictions are well below the allowed limits as stated by Swedish and European standards. The aim of the present work is to study the particle pollutants with emphasis on PM2.5 in the ambient air and to identify the specific contribution from the new incineration plant. Many different sources...

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

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

    2015-10-20

    ) two well-characterized source of soot particles and (b) a flow reactor for controlled OH and/or O3 oxidation of relevant gas phase species to produce well-characterized SOA particles. After formation, the aerosol particles are subjected to physical and chemical processes that simulate aerosol growth and aging. A suite of instruments in our laboratory is used to characterize the physical and chemical properties of aerosol particles before and after processing. The Time of Flight Aerosol Mass Spectrometer (ToF-AMS) together with a Scanning Mobility Particle Sizer (SMPS) measures particle mass, volume, density, composition (including black carbon content), dynamic shape factor, and fractal dimension. The–ToF-AMS was developed at ARI with Boston College participation. About 120 AMS instruments are now in service (including 5 built for DOE laboratories) performing field and laboratory studies world-wide. Other major instruments include a thermal denuder, two Differential Mobility Analyzers (DMA), a Cloud Condensation Nuclei Counter (CCN), a Thermal desorption Aerosol GC/MS (TAG) and the new Soot Particle Aerosol Mass Spectrometer (SP-AMS). Optical instrumentation required for the studies have been brought to our laboratory as part of ongoing and planned collaborative projects with colleagues from DOE, NOAA and university laboratories. Optical instruments that will be utilized include a Photoacoustic Spectrometer (PAS), a Cavity Ring Down Aerosol Extinction Spectrometer (CRD-AES), a Photo Thermal Interferometer (PTI), a new 7-wavelength Aethalometer and a Cavity Attenuated Phase Shift Extinction Monitor (CAPS). These instruments are providing aerosol absorption, extinction and scattering coefficients at a range of atmospherically relevant wavelengths. During the past two years our work has continued along the lines of our original proposal. We report on 12 completed and/or continuing projects conducted during the period 08/14 to 0814/2015. These projects are described in

  11. Dynamics of neutral and charged aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Leppae, J.

    2012-07-01

    Atmospheric aerosol particles have various climate effects and adverse health effects, which both depend on the size and number concentration of the particles. Freshly-formed particles are not large enough to impact neither health nor climate and they are most susceptible to removal by collisions with larger pre-existing particles. Consequently, the knowledge of both the formation and the growth rate of particles are crucially important when assessing the health and climate effects of atmospheric new particle formation. The purpose of this thesis is to increase our knowledge of the dynamics of neutral and charged aerosol particles with a specific interest towards the particle growth rate and processes affecting the aerosol charging state. A new model, Ion-UHMA, which simulates the dynamics of neutral and charged particles, was developed for this purpose. Simple analytical formulae that can be used to estimate the growth rate due to various processes were derived and used to study the effects of charged particles on the growth rate. It was found that the growth rate of a freshly-formed particle population due to condensation and coagulation could be significantly increased when a considerable fraction of the particles are charged. Finally, recent data-analysis methods that have been applied to the aerosol charging states obtained from the measurements were modified for a charge asymmetric framework. The methods were then tested on data obtained from aerosol dynamics simulations. The methods were found to be able to provide reasonable estimates on the growth rate and proportion of particles formed via ion-induced nucleation, provided that the growth rate is high enough and that the charged particles do not grow much more rapidly than the neutral ones. A simple procedure for estimating whether the methods are suitable for analysing data obtained in specific conditions was provided. In this thesis, the dynamics of neutral and charged aerosol particles were studied in

  12. Single-particle characterization of the High Arctic summertime aerosol

    Directory of Open Access Journals (Sweden)

    B. Sierau

    2014-01-01

    Full Text Available Single-particle mass spectrometric measurements were carried out in the High Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker \\textit{Oden} and was part of the Arctic Summer Cloud Ocean Study (ASCOS. The instrument deployed was an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS that provides information on the chemical composition of individual particles and their mixing state in real-time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 nm to 3000 nm in diameter showed mass spectrometric patterns indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the High Arctic. To assess the importance of long-range particle sources for aerosol–cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a~minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest a presence of a

  13. Particle size dependent response of aerosol counters

    Science.gov (United States)

    Ankilov, A.; Baklanov, A.; Colhoun, M.; Enderle, K.-H.; Gras, J.; Julanov, Yu.; Kaller, D.; Lindner, A.; Lushnikov, A. A.; Mavliev, R.; McGovern, F.; O'Connor, T. C.; Podzimek, J.; Preining, O.; Reischl, G. P.; Rudolf, R.; Sem, G. J.; Szymanski, W. W.; Vrtala, A. E.; Wagner, P. E.; Winklmayr, W.; Zagaynov, V.

    During an international workshop at the Institute for Experimental Physics of the University of Vienna, Austria, which was coordinated within the Committee on Nucleation and Atmospheric Aerosols (IAMAS-IUGG), 10 instruments for aerosol number concentration measurement were studied, covering a wide range of methods based on various different measuring principles. In order to investigate the detection limits of the instruments considered with respect to particle size, simultaneous number concentration measurements were performed for monodispersed aerosols with particle sizes ranging from 1.5 to 50 nm diameter and various compositions. The instruments considered show quite different response characteristics, apparently related to the different vapors used in the various counters to enlarge the particles to an optically detectable size. A strong dependence of the 50% cutoff diameter on the particle composition in correlation with the type of vapor used in the specific instrument was found. An enhanced detection efficiency for ultrafine hygroscopic sodium chloride aerosols was observed with water operated systems, an analogous trend was found for n-butanol operated systems with nonhygroscopic silver and tungsten oxide particles.

  14. 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.

  15. Giant dendritic carbonaceous particles in Soweto aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Wentzel, M.; Annegarn, H.J.; Helas, G.; Weinbruch, S.; Balogh, A.G.; Sithole, J.S. [Max Planck Institute of Chemistry, Mainz (Germany). Biogeochemistry Dept.

    1999-03-01

    Gravimetric analyses of aerosol filter samples from Soweto, southwest of Johannesburg, have revealed an anomalous mass-size distribution. Instead of the coal fire generated aerosol forming sub-micron aerosols as expected, most of the mass of the winter smoke is in particles greater than 3{mu}m aerodynamic diameter. A high-resolution scanning electron microscope was used to examine coarse and fine-mode aerosol fractions from two contrasting sites in the conurbation. Unanticipated giant carbonaceous conglomerates (10-100 {mu}m diameter), which comprise the bulk of the aerosol mass on the filters examined, were found. The outer shape of the conglomerates tends towards spherical, rather than the branched, chain-like structures of high-temperature soot. Internal structure varies from highly dendritic with 20-nm-wide branches, through a coarser sponge-like structure to an almost solid `melted toffee` irregular surface. Possible modes of formation of these conglomerates are discussed in terms of condensation aerosols conglomeration, and subsequent partial melting or solvent condensation. The occurrence of the giant carbonaceous conglomerates as a general feature of the Soweto winter atmosphere explains the anomalous size-mass distribution results from bulk filter analyses.

  16. Time Resolved Measurements of Primary Biogenic Aerosol Particles in Amazonia

    Science.gov (United States)

    Wollny, A. G.; Garland, R.; Pöschl, U.

    2009-04-01

    Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the Amazonian Aerosol Characterization Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. This presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 µm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as "viable aerosols" or "fluorescent bioparticles" (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. Data from the UVAPS were averaged over 5 minute time intervals. The presence of bioparticles in the observed size range has been

  17. Sources and transformations of atmospheric aerosol particles

    Science.gov (United States)

    Cross, Eben Spencer

    Aerosol particles are an important component of the Earth-Atmosphere system because of their influence on the radiation budget both directly (through absorption and scattering) and indirectly (through cloud condensation nuclei (CCN) activity). The magnitude of the raditaive forcing attributed to the direct and indirect aerosol effects is highly uncertain, leading to large uncertainties in projections of global climate change. Real-time measurements of aerosol properties are a critical step toward constraining the uncertainties in current global climate modeling and understanding the influence that anthropogenic activities have on the climate. The objective of the work presented in this thesis is to gain a more complete understanding of the atmospheric transformations of aerosol particles and how such transformations influence the direct and indirect radiative effects of the particles. The work focuses on real-time measurements of aerosol particles made with the Aerodyne Aerosol Mass Spectrometer (AMS) developed in collaboration with the Boston College research group. A key feature of the work described is the development of a light scattering module for the AMS. Here we present the first results obtained with the integrated light scattering - AMS system. The unique and powerful capabilities of this new instrument combination are demonstrated through laboratory experiments and field deployments. Results from two field studies are presented: (1) The Northeast Air Quality Study (NEAQS), in the summer of 2004, conducted at Chebogue Point, Nova Scotia and (2) The Megacity Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in and around Mexico City, Mexico in March of 2006. Both field studies were designed to study the transformations that occur within pollution plumes as they are transported throughout the atmosphere. During the NEAQS campaign, the pollution plume from the Northeastern United States was intercepted as it was

  18. Nuclear track radiography of 'hot' aerosol particles

    CERN Document Server

    Boulyga, S F; Kievets, M K; Lomonosova, E M; Zhuk, I V; Yaroshevich, O I; Perelygin, V P; Petrova, R I; Brandt, R; Vater, P

    1999-01-01

    Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the alpha-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (gamma,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 9 Pu and sup 2 sup 4 sup 1 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 sup - sup 6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical imag...

  19. Formation of the Aerosol of Space Origin in Earth's Atmosphere

    Science.gov (United States)

    Kozak, P. M.; Kruchynenko, V. G.

    2011-01-01

    The problem of formation of the aerosol of space origin in Earth s atmosphere is examined. Meteoroids of the mass range of 10-18-10-8 g are considered as a source of its origin. The lower bound of the mass range is chosen according to the data presented in literature, the upper bound is determined in accordance with the theory of Whipple s micrometeorites. Basing on the classical equations of deceleration and heating for small meteor bodies we have determined the maximal temperatures of the particles, and altitudes at which they reach critically low velocities, which can be called as velocities of stopping . As a condition for the transformation of a space particle into an aerosol one we have used the condition of non-reaching melting temperature of the meteoroid. The simplified equation of deceleration without earth gravity and barometric formula for the atmosphere density are used. In the equation of heat balance the energy loss for heating is neglected. The analytical solution of the simplified equations is used for the analysis.

  20. Single Particle Characterization of Free Tropospheric Aerosols at the Pico Mountain Observatory over the North Atlantic

    Science.gov (United States)

    Mazzoleni, C.; China, S.; Scarnato, B. V.; Moffet, R.; OBrien, R. E.; Gilles, M. K.; Fialho, P. J.; Ampadu, M.; Kumar, S.; Dzepina, K.; Wright, K.; Sharma, N.; Zhang, B.; Owen, R. C.; Perlinger, J. A.; Jacques, H.; Helmig, D.; Dziobak, M.; Kramer, L. J.; Mazzoleni, L. R.

    2014-12-01

    Free tropospheric aerosols are being studied at the Pico Mountain Observatory, located near the top of the Pico volcano in the Azores, Portugal (38.47°N, 28.40°W, 2225m asl). Typically above the marine boundary layer in the summer, this is an ideal site to study aerosol transported over long distances across the Atlantic Ocean. Aerosols reaching the Observatory often originate from North America and sometimes from Africa and Europe. Aerosols instrumentation deployed at the site include: a) an optical particle counter, b) a 7-wavelength aethalometer to measure black carbon equivalent mass concentration, c) a 3-wavelength nephelometer to measure total and backward light scattering, d) four high volume samplers for aerosol chemical characterization, and e) a sequential aerosol sampler and a 4-stage impactor to collect particles on different substrates for microscopy analysis. The origin and transport pathways of the air masses sampled at the site are determined using FLEXible PARTicle (FLEXPART) dispersion modeling retroplume analysis. Single particle morphology and mixing states were determined using electron microscopy, energy dispersive X-ray spectroscopy, and scanning transmission x-ray microscopy. This study provides an overview of different types of aerosol collected at Pico Mountain Observatory. We investigated morphology and mixing of various types of particles, including dust, soot, salt and organic particles transported to the Observatory. Soot particles were often mixed/coated with other material and exhibited very compact shape. Dust particles were often mixed with sulfur containing species. We also observed dust particles that were mixed with coated soot particles. During some events, we observed soot and sulfate aerosol trapped within organic matter. The results of this study have implications on how aerosol particles and their internal mixing can be represented in numerical models for remote regions of the free troposphere.

  1. Resuspension of Aerosol Particles from Evaporated Rain Drops to the Coarse Mode

    Science.gov (United States)

    Wang, H.; Easter, R. C.; Ganguly, D.; Singh, B.; Rasch, P. J.

    2015-12-01

    Precipitation scavenging (i.e., wet removal) has long been recognized as one of the major removal processes for tropospheric aerosol particles, and the dominant one for accumulation-mode size particles. When rain drops evaporate, the aerosol material contained in drops is resuspended, and this process has received much less attention. Unlike the resuspension from evaporated cloud droplets, the aerosol particles resuspended from evaporated rain drops have much larger sizes than most of the aerosol particles that acted as cloud condensation nuclei (CCN), became cloud borne, and then were collected by rain drops, because each rain drop generally collects thousands of cloud droplets. Here we present some aspects of this resuspension process obtained from modeling studies. First, we investigate some details of the process using a simple drop-size resolved model of raindrop evaporation in sub-saturated air below cloud base. Using these results, we then investigate different treatments of this process in a global aerosol and climate model that employs a modal aerosol representation. Compared to the model's original treatment of this process in which rain-borne aerosol is resuspended to the mode that it came from with its original size, the new treatment that resuspends to the coarse mode produces notable reductions in global CCN concentrations, as well as sulfate, black carbon, and organic aerosol mass, because the resuspended aerosol particles have much shorter lifetimes due to their larger sizes. Somewhat surprisingly, there are also notable reductions in coarse-mode sea salt and mineral dust burdens. These species are resuspended to the coarse mode in both the original and new treatments, but these resuspended particles are fewer in number and larger in size in the new treatment. This finding highlights some issues of the modal aerosol treatment for coarse mode particles.

  2. Methods of analyzing composition of aerosol particles

    Science.gov (United States)

    Reilly, Peter T.A.

    2013-02-12

    An aerosol particle analyzer includes a laser ablation chamber, a gas-filled conduit, and a mass spectrometer. The laser ablation chamber can be operated at a low pressure, which can be from 0.1 mTorr to 30 mTorr. The ablated ions are transferred into a gas-filled conduit. The gas-filled conduit reduces the electrical charge and the speed of ablated ions as they collide and mix with buffer gases in the gas-filled conduit. Preferably, the gas filled-conduit includes an electromagnetic multipole structure that collimates the nascent ions into a beam, which is guided into the mass spectrometer. Because the gas-filled conduit allows storage of vast quantities of the ions from the ablated particles, the ions from a single ablated particle can be analyzed multiple times and by a variety of techniques to supply statistically meaningful analysis of composition and isotope ratios.

  3. Single-particle Analyses of Compositions, Morphology, and Viscosity of Aerosol Particles Collected During GoAmazon2014

    Science.gov (United States)

    Adachi, K.; Gong, Z.; Bateman, A. P.; Martin, S. T.; Cirino, G. G.; Artaxo, P.; Sedlacek, A. J., III; Buseck, P. R.

    2014-12-01

    Single-particle analysis using transmission electron microscopy (TEM) shows composition and morphology of individual aerosol particles collected during the GoAmazon2014 campaign. These TEM results indicate aerosol types and mixing states, both of which are important for evaluating particle optical properties and cloud condensation nuclei activity. The samples were collected at the T3 site, which is located in the Amazon forest with influences from the urban pollution plume from Manaus. Samples were also collected from the T0 site, which is in the middle of the jungle with minimal to no influences of anthropogenic sources. The aerosol particles mainly originated from 1) anthropogenic pollution (e.g., nanosphere soot, sulfate), 2) biogenic emissions (e.g., primary biogenic particles, organic aerosols), and 3) long-range transport (e.g., sea salts). We found that the biogenic organic aerosol particles contain homogeneously distributed potassium. Particle viscosity is important for evaluating gas-particle interactions and atmospheric chemistry for the particles. Viscosity can be estimated from the rebounding behavior at controlled relative humidities, i.e., highly viscous particles display less rebound on a plate than low-viscosity particles. We collected 1) aerosol particles from a plate (non-rebounded), 2) those that had rebounded from the plate and were then captured onto an adjacent sampling plate, and 3) particles from ambient air using a separate impactor sampler. Preliminary results show that more than 90% of non-rebounded particles consisted of nanosphere soot with or without coatings. The coatings mostly consisted of organic matter. Although rebounded particles also contain nanosphere soot (number fraction 64-69%), they were mostly internally mixed with sulfate, organic matter, or their mixtures. TEM tilted images suggested that the rebounded particles were less deformed on the substrate, whereas the non-rebounded particles were more deformed, which could

  4. Measurements of Primary Biogenic Aerosol Particles with an Ultraviolet Aerodynamic Particle Sizer (UVAPS) During AMAZE-08

    Science.gov (United States)

    Wollny, A. G.; Garland, R.; Pöschl, U.

    2008-12-01

    Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the AMazonian Aerosol CharacteriZation Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. The presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 μm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as 'viable aerosols' or 'fluorescent bioparticles' (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. First data analyses show a pronounced peak of FBAP at diameters around 2-3 μm. In this size range the biogenic particle fraction was

  5. Sources and composition of urban aerosol particles

    Science.gov (United States)

    Vogt, M.; Johansson, C.; Mårtensson, M.; Struthers, H.; Ahlm, L.; Nilsson, D.

    2011-09-01

    From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp) from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx) and BC measured on a densely trafficked street) and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs) for non-volatile particles traffic activity data. Light (LDV) and heavy duty vehicle (HDV) EFs were estimated using multiple linear regression and reveal that for non-volatile particulate matter in the 0.25 to 0.6 μm Dp range, the EFHDV is approximately twice as high as the EFLDV, the difference not being statistically significant.

  6. Characterizing gas flow from aerosol particle injectors

    CERN Document Server

    Horke, Daniel; Worbs, Lena; Küpper, Jochen

    2016-01-01

    A novel methodology for measuring gas flow from small orifices or nozzles into vacuum is presented. It utilizes a high-intensity femtosecond laser pulse to create a plasma within the gas plume produced by the nozzle, which is imaged by a microscope. Calibration of the imaging system at known chamber pressures allows for the extraction of absolute number densities, and we show detection down to helium densities of $4\\times10^{16}$~cm$^{-3}$ with a spatial resolution of a few micrometer. The technique is used to characterize the gas flow from a convergent-nozzle aerosol injector as used in single-particle diffractive imaging experiments at free-electron laser sources. Based on the measured gas-density profile we estimate the scattering background signal under typical operating conditions of single-particle imaging experiments and estimate that fewer than 50 photons per shot can be expected on the typical detector of such an experiment.

  7. Factors affecting the indoor concentrations of carbonaceous aerosols of outdoor origin

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa M.; Kirchstetter, Thomas W.; Thatcher, Tracy L.; Hering, Susanne V.; Brown, Nancy J.

    2007-06-25

    A field study was conducted in an unoccupied single story residence in Clovis, California to provide data to address issues important to assess the indoor exposure to particles of outdoor origin. Measurements of black and organic carbonaceous aerosols were performed using a variety of methods, resulting in both near real-time measurements as well as integrated filter based measurements. Comparisons of the different measurement methods show that it is crucial to account for gas phase adsorption artifacts when measuring organic carbon (OC). Measured concentrations affected by the emissions of organic compounds sorbed to indoor surfaces imply a higher degree of infiltration of outdoor organic carbon aerosols into the indoor environment for our unoccupied house. Analysis of the indoor and outdoor data for black carbon (BC) aerosols show that, on average, the indoor concentration of black carbon aerosols behaves in a similar manner to sulfate aerosols. In contrast, organic carbon aerosols are subject to chemical transformations indoors that, for our unoccupied home, resulted in lower indoor OC concentrations than would be expected by physical loss mechanisms alone. These results show that gas to particle partitioning of organic compounds, as well as gas to surface interactions within the residence, are an important process governing the indoor concentration to OC aerosols of outdoor origin.

  8. On-line matrix addition for detecting aerosol particles

    Institute of Scientific and Technical Information of China (English)

    ZHOU; Liuzhu; ZHU; Yuan; GUO; Xiaoyong; ZHAO; Wenwu; ZHENG; Haiyang; Gu; Xuejun; FANG; Li; ZHANG; Weijun

    2006-01-01

    Single aerosol particles were measured by matrix-assisted laser desorption/ionization (MALDI) with an aerosol time-of-flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed matrix addition by condensation onto the particles. The coated particles entered the ion source through three-stage differentially pumped capillary inlet and were then ionized by a focused 266 nm Nd:YAG laser. The mass spectra and aerodynamic size of the single particles can be obtained simultaneously. The on-line matrix addition technique makes it possible to identify biological aerosols in real-time.

  9. Sources and composition of urban aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Vogt

    2011-09-01

    Full Text Available From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass <1 μm Dp (PM1 with water soluble soil contributing 11% and water insoluble soil 47%. Carbonaceous compounds were at the most 27% of PM1 mass. It was found that heating the air from the tower to 200 °C resulted in the loss of approximately 60% of the aerosol volume at 0.25 μm Dp whereas only 40% of the aerosol volume was removed at 0.6 μm Dp. Further heating to 300 °C caused very little additional losses <0.6 μm Dp. The chemical analysis did not include carbonaceous compounds, but based on the difference between the total mass concentration and the sum of the analyzed non-carbonaceous materials, it can be assumed that the non-volatile particulate material (heated to 300 °C consists mainly of carbonaceous compounds, including elemental carbon. Furthermore, it was found that the non-volatile particle fraction <0.6 μm Dp correlated (r2 = 0.4 with the BC concentration at roof level in the city, supporting the assumption that the non-volatile material consists of carbonaceous compounds. The average diurnal cycles of the BC emissions from road traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx and BC measured on a densely trafficked street and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs for non

  10. Microphysical processing of aerosol particles in orographic clouds

    Directory of Open Access Journals (Sweden)

    S. Pousse-Nottelmann

    2015-01-01

    Full Text Available An explicit and detailed treatment of cloud-borne particles allowing for the consideration of aerosol cycling in clouds has been implemented in the regional weather forecast and climate model COSMO. The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener-Bergeron-Findeisen process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snow flakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snow flakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. However, the processes not only impact the total aerosol number and mass, but also the shape of the aerosol size distributions by enhancing the internally mixed/soluble accumulation mode and generating coarse mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases the cloud droplet number concentration with possible

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Sources of optically active aerosol particles over the Amazon forest

    Science.gov (United States)

    Guyon, Pascal; Graham, Bim; Roberts, Gregory C.; Mayol-Bracero, Olga L.; Maenhaut, Willy; Artaxo, Paulo; Andreae, Meinrat O.

    Size-fractionated ambient aerosol samples were collected at a pasture site and a primary rainforest site in the Brazilian Amazon Basin during two field campaigns (April-May and September-October 1999), as part of the European contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA-EUSTACH). The samples were analyzed for up to 19 trace elements by particle-induced X-ray emission analysis (PIXE), for equivalent black carbon (BC e) by a light reflectance technique and for mass concentration by gravimetric analysis. Additionally, we made continuous measurements of absorption and light scattering by aerosol particles. The vertical chemical composition gradients at the forest site have been discussed in a companion article (Journal of Geophysical Research-Atmospheres 108 (D18), 4591 (doi:4510.1029/2003JD003465)). In this article, we present the results of a source identification and quantitative apportionment study of the wet and dry season aerosols, including an apportionment of the measured scattering and absorption properties of the total aerosol in terms of the identified aerosol sources. Source apportionments (obtained from absolute principal component analysis) revealed that the wet and dry season aerosols contained the same three main components, but in different (absolute and relative) amounts: the wet season aerosol consisted mainly of a natural biogenic component, whereas pyrogenic aerosols dominated the dry season aerosol mass. The third component identified was soil dust, which was often internally mixed with the biomass-burning aerosol. All three components contributed significantly to light extinction during both seasons. At the pasture site, up to 47% of the light absorption was attributed to biogenic particles during the wet season, and up to 35% at the tower site during the wet-to-dry transition period. The results from the present study suggest that, in addition to pyrogenic particles, biogenic and soil dust aerosols must be

  13. Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

    Directory of Open Access Journals (Sweden)

    E. Asmi

    2009-12-01

    Full Text Available The Antarctic near-coastal sub-micrometre aerosol particle features in summer were characterised based on measured data on aerosol hygroscopicity, size distributions, volatility and chemical ion and organic carbon mass concentrations. Hysplit model was used to calculate the history of the air masses to predict the particle origin. Additional measurements of meteorological parameters were utilised. The hygroscopic properties of particles mostly resembled those of marine aerosols. The measurements took place at 130 km from the Southern Ocean, which was the most significant factor affecting the particle properties. This is explained by the lack of additional sources on the continent of Antarctica. The Southern Ocean was thus a likely source of the particles and nucleating and condensing vapours. The particles were very hygroscopic (HGF 1.75 at 90 nm and very volatile. Most of the sub-100 nm particle volume volatilised below 100 °C. Based on chemical data, particle hygroscopic and volatile properties were explained by a large fraction of non-neutralised sulphuric acid together with organic material. The hygroscopic growth factors assessed from chemical data were similar to measured. Hygroscopicity was higher in dry continental air masses compared with the moist marine air masses. This was explained by the aging of the marine organic species and lower methanesulphonic acid volume fraction together with the changes in the inorganic aerosol chemistry as the aerosol had travelled long time over the continental Antarctica. Special focus was directed in detailed examination of the observed new particle formation events. Indications of the preference of negative over positive ions in nucleation could be detected. However, in a detailed case study, the neutral particles dominated the particle formation process. Freshly nucleated particles had the smallest hygroscopic growth factors, which increased subsequent to particle aging.

  14. Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

    Directory of Open Access Journals (Sweden)

    E. Asmi

    2010-05-01

    Full Text Available The Antarctic near-coastal sub-micrometre aerosol particle features in summer were characterised based on measured data on aerosol hygroscopicity, size distributions, volatility and chemical ion and organic carbon mass concentrations. Hysplit model was used to calculate the history of the air masses to predict the particle origin. Additional measurements of meteorological parameters were utilised. The hygroscopic properties of particles mostly resembled those of marine aerosols. The measurements took place at 130 km from the Southern Ocean, which was the most significant factor affecting the particle properties. This is explained by the lack of additional sources on the continent of Antarctica. The Southern Ocean was thus a likely source of the particles and nucleating and condensing vapours. The particles were very hygroscopic (HGF 1.75 at 90 nm and very volatile. Most of the sub-100 nm particle volume volatilised below 100 °C. Based on chemical data, particle hygroscopic and volatile properties were explained by a large fraction of non-neutralised sulphuric acid together with organic material. The hygroscopic growth factors assessed from chemical data were similar to measured. Hygroscopicity was higher in dry continental air masses compared with the moist marine air masses. This was explained by the aging of the marine organic species and lower methanesulphonic acid volume fraction together with the changes in the inorganic aerosol chemistry as the aerosol had travelled long time over the continental Antarctica. Special focus was directed in detailed examination of the observed new particle formation events. Indications of the preference of negative over positive ions in nucleation could be detected. However, in a detailed case study, the neutral particles dominated the particle formation process. Freshly nucleated particles had the smallest hygroscopic growth factors, which increased subsequent to particle aging.

  15. Microphysical processing of aerosol particles in orographic clouds

    Directory of Open Access Journals (Sweden)

    S. Pousse-Nottelmann

    2015-08-01

    aerosol cycling in clouds has been implemented into COSMO-Model, the regional weather forecast and climate model of the Consortium for Small-scale Modeling (COSMO. The effects of aerosol scavenging, cloud microphysical processing and regeneration upon cloud evaporation on the aerosol population and on subsequent cloud formation are investigated. For this, two-dimensional idealized simulations of moist flow over two bell-shaped mountains were carried out varying the treatment of aerosol scavenging and regeneration processes for a warm-phase and a mixed-phase orographic cloud. The results allowed us to identify different aerosol cycling mechanisms. In the simulated non-precipitating warm-phase cloud, aerosol mass is incorporated into cloud droplets by activation scavenging and released back to the atmosphere upon cloud droplet evaporation. In the mixed-phase cloud, a first cycle comprises cloud droplet activation and evaporation via the Wegener–Bergeron–Findeisen (WBF process. A second cycle includes below-cloud scavenging by precipitating snow particles and snow sublimation and is connected to the first cycle via the riming process which transfers aerosol mass from cloud droplets to snowflakes. In the simulated mixed-phase cloud, only a negligible part of the total aerosol mass is incorporated into ice crystals. Sedimenting snowflakes reaching the surface remove aerosol mass from the atmosphere. The results show that aerosol processing and regeneration lead to a vertical redistribution of aerosol mass and number. Thereby, the processes impact the total aerosol number and mass and additionally alter the shape of the aerosol size distributions by enhancing the internally mixed/soluble Aitken and accumulation mode and generating coarse-mode particles. Concerning subsequent cloud formation at the second mountain, accounting for aerosol processing and regeneration increases the cloud droplet number concentration with possible implications for the ice crystal number

  16. Optimized sparse-particle aerosol representations for modeling cloud-aerosol interactions

    Science.gov (United States)

    Fierce, Laura; McGraw, Robert

    2016-04-01

    Sparse representations of atmospheric aerosols are needed for efficient regional- and global-scale chemical transport models. Here we introduce a new framework for representing aerosol distributions, based on the method of moments. Given a set of moment constraints, we show how linear programming can be used to identify collections of sparse particles that approximately maximize distributional entropy. The collections of sparse particles derived from this approach reproduce CCN activity of the exact model aerosol distributions with high accuracy. Additionally, the linear programming techniques described in this study can be used to bound key aerosol properties, such as the number concentration of CCN. Unlike the commonly used sparse representations, such as modal and sectional schemes, the maximum-entropy moment-based approach is not constrained to pre-determined size bins or assumed distribution shapes. This study is a first step toward a new aerosol simulation scheme that will track multivariate aerosol distributions with sufficient computational efficiency for large-scale simulations.

  17. Transmission electron microscopy study of aerosol particles from the brown hazes in northern China

    Science.gov (United States)

    Li, Weijun; Shao, Longyi

    2009-05-01

    Airborne aerosol collections were performed in urban areas of Beijing that were affected by regional brown haze episodes over northern China from 31 May to 12 June 2007. Morphologies, elemental compositions, and mixing states of 810 individual aerosol particles of different sizes were obtained by transmission electron microscopy coupled with energy-dispersive X-ray spectrometry. The phases of some particles were verified using selected-area electron diffraction. Aerosol particle types less than 10 μm in diameter include mineral, complex secondary (Ca-S, K-, and S-rich), organic, soot, fly ash, and metal (Fe-rich and Zn-bearing). Most soot, fly ash, and organic particles are less than 2 μm in diameter. Approximately 84% of the analyzed mineral particles have diameters between 2 and 10 μm, while 81% of the analyzed complex secondary and metal particles are much smaller, from 0.1 to 2 μm. Trajectory analysis with fire maps show that southerly air masses arriving at Beijing have been transported through many agricultural biomass burning sites and heavy industrial areas. Spherical fly ash and Fe-rich particles were from industrial emissions, and abundant K-rich and organic particles likely originated from field burning of crop residues. Abundant Zn-bearing particles are associated with industrial activities and local waste incinerators. On the basis of the detailed analysis of 443 analyzed aerosol particles, about 70% of these particles are internally mixed with two or more aerosol components from different sources. Most mineral particles are covered with visible coatings that contain N, O, Ca (or Mg), minor S, and Cl. K- and S-rich particles tend to be coagulated with fly ash, soot, metal, and fine-grained mineral particles. Organic materials internally mixed with K- and S-rich particles can be their inclusions and coatings.

  18. A conceptual framework for mixing structures in individual aerosol particles

    Science.gov (United States)

    Li, Weijun; Sun, Jiaxing; Xu, Liang; Shi, Zongbo; Riemer, Nicole; Sun, Yele; Fu, Pingqing; Zhang, Jianchao; Lin, Yangting; Wang, Xinfeng; Shao, Longyi; Chen, Jianmin; Zhang, Xiaoye; Wang, Zifa; Wang, Wenxing

    2016-11-01

    This study investigated the particle size- and age-dependent mixing structures of individual particles in clean and polluted air. Aerosols were classified into eight components: sea salt, mineral dust, fly ash, metal, soot, sulfates, nitrates, and organic matter (OM). Based on our aerosol classification, a particle that consists of two or more aerosol components can be defined as an internally mixed particle. Otherwise, it is considered to be an externally mixed particle. Within the internally mixed particle class, we identified four heterogeneous mixing structures: core-shell, dumbbell, OM coating, and dispersed OM, as well as one homogeneous-like mixing structure. Homogeneous-like mixing mainly occurred in fine particles (<1 µm), while the frequency of heterogeneously mixed particles increased with particle size. Our study demonstrated that particle mixing structures depend on particle size and location and evolve with time. OM-coating and core-shell structures are important indicators for particle aging in air as long as they are distant from specific emission sources. Long-range transported particles tended to have core-shell and OM-coating structures. We found that secondary aerosol components (e.g., sulfates, nitrates, and organics) determined particle mixing structures, because their phases change following particle hydration and dehydration under different relative humidities. Once externally mixed particles are transformed into internally mixed particles, they cannot revert to their former state, except when semivolatile aerosol components are involved. Categorizing mixing structures of individual particles is essential for studying their optical and hygroscopic properties and for tracing the development of their physical or chemical properties over time.

  19. Basic phenomena utilised in aerosol particle measurement techniques; Hiukkasmittaustekniikoiden perusilmioet

    Energy Technology Data Exchange (ETDEWEB)

    Janka, K. [Dekati Oy, Tampere (Finland)

    2006-10-15

    The project deals with development of basic phenomena and mechanism utilised in aerosol particle measurement techniques. The areas under development are: particle-charging techniques, photoelectric charging, particle concentrating using virtual-impactor technique, and optical characterising techniques of particles. Results will be applied on detection techniques of bioaerosol attract, particle emission sensors for diesel exhaust gases, and widening the application areas of existing measurement techniques. (orig.)

  20. An overview of aerosol particle sensors for size distribution measurement

    Directory of Open Access Journals (Sweden)

    Panich Intra

    2007-08-01

    Full Text Available Fine aerosols are generally referred to airborne particles of diameter in submicron or nanometer size range. Measurement capabilities are required to gain understanding of these particle dynamics. One of the most important physical and chemical parameters is the particle size distribution. The aim of this article is to give an overview of recent development of already existing sensors for particle size distribution measurement based on electrical mobility determination. Available instruments for particle size measurement include a scanning mobility particle sizer (SMPS, an electrical aerosol spectrometer (EAS, an engine exhaust particle sizer (EEPS, a bipolar charge aerosol classifier (BCAC, a fast aerosol spectrometer (FAS a differential mobility spectrometer (DMS, and a CMU electrical mobility spectrometer (EMS. The operating principles, as well as detailed physical characteristics of these instruments and their main components consisting of a particle charger, a mobility classifier, and a signal detector, are described. Typical measurements of aerosol from various sources by these instruments compared with an electrical low pressure impactor (ELPI are also presented.

  1. Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site (Mainz, Germany

    Directory of Open Access Journals (Sweden)

    B. Winterholler

    2008-05-01

    Full Text Available Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles.

    Primary aerosol particles retain the original isotopic signature of their source. The isotopic composition of secondary sulfates depends on the isotopic composition of precursor SO2 and the oxidation process. The fractionation with respect to the source SO2 is −9‰ for homogeneous and +16.5‰ for heterogeneous oxidation. The sulfur isotope ratio of secondary sulfate particles can therefore be used to identify the oxidation pathway by which this sulfate was formed. With the new single particle technique, different types of primary and secondary sulfates were first identified based on their chemical composition, and then their individual isotopic signature was measured separately. Our samples were collected in Mainz, Germany, in an urban environment. Secondary sulfates (ammonium sulfate, gypsum, mixed sulfates and coatings on silicates or organic aerosol dominated sulfate loadings in our samples. Comparison of the chemical and isotopic composition of secondary sulfates showed that the isotopic composition was homogeneous, independent of the chemical composition. This is typical for particles that derive from in-cloud processing. The isotopic composition of the source SO2 of secondary sulfates was calculated based on the isotopic composition of particles with known oxidation pathway and showed a strong dependence on wind direction. The contribution of heterogeneous

  2. Carbonaceous aerosol particles from common vegetation in the Grand Canyon

    Energy Technology Data Exchange (ETDEWEB)

    Hallock, K.A.; Mazurek, M.A. (Brookhaven National Lab., Upton, NY (United States)); Cass, G.R. (California Inst. of Tech., Pasadena, CA (United States). Dept. of Environmental Engineering Science)

    1992-05-01

    The problem of visibility reduction in the Grand Canyon due to fine organic aerosol particles in the atmosphere has become an area of increased environmental concern. Aerosol particles can be derived from many emission sources. In this report, we focus on identifying organic aerosols derived from common vegetation in the Grand Canyon. These aerosols are expected to be significant contributors to the total atmospheric organic aerosol content. Aerosol samples from living vegetation were collected by resuspension of surface wax and resin components liberated from the leaves of vegetation common to areas of the Grand Canyon. The samples were analyzed using high-resolution gas chromatography/mass spectrometry (GC/MS). Probable identification of compounds was made by comparison of sample spectra with National Institute of Standards and Technology (NIST) mass spectral references and positive identification of compounds was made when possible by comparison with authentic standards as well as NIST references. Using these references, we have been able to positively identify the presence of n-alkane and n-alkanoic acid homolog series in the surface waxes of the vegetation sampled. Several monoterpenes, sesquiterpenes, and diterpenes were identified also as possible biogenic aerosols which may contribute to the total organic aerosol abundance leading to visibility reduction in the Grand Canyon.

  3. Phosphorus-bearing Aerosol Particles From Volcanic Plumes

    Science.gov (United States)

    Obenholzner, J. H.; Schroettner, H.; Poelt, P.; Delgado, H.; Caltabiano, T.

    2003-12-01

    Particles rich in P or bulk geochemical data of volcanic aerosol particles showing high P contents are known from many volcanic plumes (Stanton, 1994; Obenholzner et al., 2003). FESEM/EDS analysis of individual particles obtained from the passively degassing plume of Popocatepetl volcano, Mx. (1997) and from the plume of Stromboli (May 2003) show P frequently. Even at the high resolution of the FESEM, euhedral apatite crystals could not be observed. At Popocatepetl (1997) spherical Ca-P-O particles are common. Fluffy, fractal or botryoidal particles also can contain EDS-detectable amounts of P. The EDS spectrum of such particles can comprise various elements. However most particles show P, S and Cl. P-S and P-S-metal species are known in chemistry but do they occur in volcanic plumes? Stoichiometric considerations had been made in the past suggesting the existence of P-S species in plumes (Stanton 1994), gas sampling and remote gas monitoring systems have not detected yet such molecules in plumes. The particle spectrum of the reawakened Popocateptel volcano might be related to accumulation of volatiles at the top of a magma chamber during the phase of dormancy. P-Fe rich, Ca-free aggregates are also known from the eruption of El Chichon 1982 (SEM/EDS by M. Sheridan, per. comm. 08-24-2003). Persistently active volcanoes (i.e. Stromboli) represent a different category according to continuous degassing and aerosol particle formation. A particle collector ( ca. 90 ml/min) accompanied a COSPEC helicopter flight at Stromboli (May 15, 2003) after one of the rare types of sub-plinian events on April 5 2003. P-bearing particles are very common. For instance, an Fe oxide grain (diam. = 2 æm) is partially covered by fluffy and euhedral P-bearing matter. The elements detected are P, Cl, Na, Mg, Al, Si, K, Ca, Ti and (Fe). The fluffy and the euhedral (rhombohedral?) matter show in SE-BSE-mix image almost identical grey colors. At Stromboli and Popocatepetl particles on which

  4. The on-line analysis of aerosol-delivered pharmaceuticals via single particle aerosol mass spectrometry.

    Science.gov (United States)

    Morrical, Bradley D; Balaxi, Maria; Fergenson, David

    2015-07-15

    The use of single particle aerosol mass spectrometry (SPAMS) was evaluated for the analysis of inhaled pharmaceuticals to determine the mass distribution of the individual active pharmaceutical ingredients (API) in both single ingredient and combination drug products. SPAMS is an analytical technique where the individual aerodynamic diameters and chemical compositions of many aerosol particles are determined in real-time. The analysis was performed using a Livermore Instruments SPAMS 3.0, which allowed the efficient analysis of aerosol particles with broad size distributions and can acquire data even under a very large particle load. Data similar to what would normally require roughly three days of experimentation and analysis was collected in a five minute period and analyzed automatically. The results were computed to be comparable to those returned by a typical Next Generation Impactor (NGI) particle size distribution experiment.

  5. New apparatus of single particle trap system for aerosol visualization

    Science.gov (United States)

    Higashi, Hidenori; Fujioka, Tomomi; Endo, Tetsuo; Kitayama, Chiho; Seto, Takafumi; Otani, Yoshio

    2014-08-01

    Control of transport and deposition of charged aerosol particles is important in various manufacturing processes. Aerosol visualization is an effective method to directly observe light scattering signal from laser-irradiated single aerosol particle trapped in a visualization cell. New single particle trap system triggered by light scattering pulse signal was developed in this study. The performance of the device was evaluated experimentally. Experimental setup consisted of an aerosol generator, a differential mobility analyzer (DMA), an optical particle counter (OPC) and the single particle trap system. Polystylene latex standard (PSL) particles (0.5, 1.0 and 2.0 μm) were generated and classified according to the charge by the DMA. Singly charged 0.5 and 1.0 μm particles and doubly charged 2.0 μm particles were used as test particles. The single particle trap system was composed of a light scattering signal detector and a visualization cell. When the particle passed through the detector, trigger signal with a given delay time sent to the solenoid valves upstream and downstream of the visualization cell for trapping the particle in the visualization cell. The motion of particle in the visualization cell was monitored by CCD camera and the gravitational settling velocity and the electrostatic migration velocity were measured from the video image. The aerodynamic diameter obtained from the settling velocity was in good agreement with Stokes diameter calculated from the electrostatic migration velocity for individual particles. It was also found that the aerodynamic diameter obtained from the settling velocity was a one-to-one function of the scattered light intensity of individual particles. The applicability of this system will be discussed.

  6. Single-particle characterization of summertime arctic aerosols collected at Ny-Alesund, Svalbard.

    Science.gov (United States)

    Geng, Hong; Ryu, Jiyeon; Jung, Hae-Jin; Chung, Hyeok; Ahn, Kang-Ho; Ro, Chul-Un

    2010-04-01

    Single-particle characterization of summertime Arctic aerosols is useful to understand the impact of air pollutants on the polar atmosphere. In the present study, a quantitative single particle analytical technique, low-Z particle electron probe X-ray microanalysis, was used to characterize 8100 individual particles overall in 16 sets of aerosol samples collected at Ny-Alesund, Svalbard, Norway on 25-31 July, 2007. Based on their X-ray spectral and secondary electron image data of individual particles, 13 particle types were identified, in which particles of marine origin were the most abundant, followed by carbonaceous and mineral dust particles. A number of aged (reacted) sea salt (and mixture) particles produced by the atmospheric reaction of genuine sea-salts, especially with NO(x) or HNO(3), were significantly encountered in almost all the aerosol samples. They greatly outnumbered genuine sea salt particles, implying that the summertime Arctic atmosphere, generally regarded as a clean background environment, is disturbed by anthropogenic air pollutants. The main sources of airborne NO(x) (or HNO(3)) are probably ship emissions around the Arctic Ocean, industry emission from northern Europe and northwestern Siberia, and renoxification of NO(3)(-) within or on the melting snow/ice surface.

  7. New aerosol particles formation in the Sao Paulo Metropolitan Area

    Science.gov (United States)

    Vela, Angel; Andrade, Maria de Fatima; Ynoue, Rita

    2016-04-01

    The Sao Paulo Metropolitan Area (SPMA), in the southeast region of Brazil, is considered a megalopolis comprised of Sao Paulo city and more 38 municipalities. The air pollutant emissions in the SPMA are related to the burning of the fuels: etanol, gasohol (gasoline with 25% ethanol) and diesel. According to CETESB (2013), the road vehicles contributed up to about 97, 87, and 80% of CO, VOCs and NOx emissions in 2012, respectively, being most of NOx associated to diesel combustion and most of CO and VOCs from gasohol and ethanol combustion. Studies conducted on ambient air pollution in the SPMA have shown that black carbon (BC) explains 21% of mass concentration of PM2.5 compared with 40% of organic carbon (OC), 20% of sulfates, and 12% of soil dust (Andrade et al., 2012). Most of the observed ambient PM2.5 mass concentration usually originates from precursors gases such as sulphur dioxide (SO2), ammonia (NH3), nitrogen oxides (NOx) and VOCs as well as through the physico-chemical processes such as the oxidation of low volatile hydrocarbons transferring to the condensed phase (McMurry et al., 2004). The Weather Research and Forecasting with Chemistry model (WRF-Chem; Grell et al. 2005), configured with three nested grid cells: 75, 15, and 3 km, is used as photochemical modeling to describe the physico-chemical processes leading to evolution of particles number and mass size distribution from a vehicular emission model developed by the IAG-USP laboratory of Atmospheric Processes and based on statistical information of vehicular activity. The spatial and temporal distributions of emissions in the finest grid cell are based on road density products compiled by the OpenStreetMap project and measurements performed inside tunnels in the SPMA, respectively. WRF-Chem simulation with coupled primary aerosol (dust and sea-salt) and biogenic emission modules and aerosol radiative effects turned on is conducted as the baseline simulation (Case_0) to evaluate the model

  8. Intercomparison of number concentration measurements by various aerosol particle counters

    Science.gov (United States)

    Ankilov, A.; Baklanov, A.; Colhoun, M.; Enderle, K.-H.; Gras, J.; Julanov, Yu.; Kaller, D.; Lindner, A.; Lushnikov, A. A.; Mavliev, R.; McGovern, F.; Mirme, A.; O'Connor, T. C.; Podzimek, J.; Preining, O.; Reischl, G. P.; Rudolf, R.; Sem, G. J.; Szymanski, W. W.; Tamm, E.; Vrtala, A. E.; Wagner, P. E.; Winklmayr, W.; Zagaynov, V.

    Total aerosol particle number concentrations, as measured by means of 16 different measurement systems, have been quantitatively compared during an international workshop at the Institute for Experimental Physics of the University of Vienna, Austria, which was coordinated within the Committee on Nucleation and Atmospheric Aerosols (ICCP-IUGG). The range of measuring instruments includes Pollak counters (PCO) in use already for several decades, presently available commercial particle counters, as well as laboratory prototypes. The operation of the instruments considered was based on different measurement principles: (1) adiabatic expansion condensation particle counter, (2) flow diffusion condensation particle counter, (3) turbulent mixing condensation particle counter, (4) laser optical particle counter, and (5) electrostatic particle measurement system. Well-defined test aerosols with various chemical compositions were considered: DEHS, sodium chloride, silver, hydrocarbons, and tungsten oxide. The test aerosols were nearly monodispersed with mean particle diameters between 4 and 520 nm, the particle number concentrations were varied over a range from about 4×10 1 to 7×10 6 cm -3. A few measurements were performed with two-component aerosol mixtures. For simultaneous concentration measurements, the various instruments considered were operated under steady state conditions in a linear flow system. A series of at least 10 single concentration measurements was performed by each individual instrument at each set of test aerosol parameters. The average of the concentration data measured by the various instruments was defined as a common reference. The number concentrations obtained from the various instruments typically agreed within a factor of about two over the entire concentration range considered. The agreement of the measured concentrations is notable considering the various different measurement principles applied in this study, and particularly in view of the

  9. Comparison of the DiSCmini aerosol monitor to a handheld condensation particle counter and a scanning mobility particle sizer for submicrometer sodium chloride and metal aerosols

    OpenAIRE

    Mills, Jessica B.; Park, Jae Hong; Peters, Thomas M.

    2013-01-01

    We evaluated the robust, lightweight DiSCmini (DM) aerosol monitor for its ability to measure the concentration and mean diameter of submicrometer aerosols. Tests were conducted with monodispersed and polydispersed aerosols composed of two particle types (sodium chloride, NaCl, and spark generated metal particles, which simulate particles found in welding fume) at three different steady-state concentration ranges (Low, 104 particles/cm3). Particle number concentration, lung deposited surface ...

  10. Synthesis of nanosized metal particles from an aerosol

    Directory of Open Access Journals (Sweden)

    Srećko R. Stopić

    2013-10-01

    Full Text Available The synthesis of metallic nanoparticles from the precursor solution of salts using the ultrasonic spray pyrolysis method was considered in this work. During the control of process parameters (surface tension and density, the concentration of solution, residence time of aerosol in the reactor, presence of additives, gas flow rate, decomposition temperature of aerosol, type of precursor and working atmosphere it is possible to guide the process in order to obtain powders with such a morphology which satisfies more complex requirements for the desired properties of advanced engineering materials.  Significant advance in the improvement of powder characteristics (lower particles sizes, better spheroidity, higher surface area was obtained by the application of the ultrasonic generator for the preparation of aerosols. Ultrasonic spray pyrolysis is performed by the action of a powerful source of ultrasound on the corresponding precursor solution forming the aerosol with a constant droplet size, which depends on the characteristics of liquid and the frequency of ultrasound. The produced aerosols were transported into the hot reactor, which enables the reaction to occur in a very small volume of a particle and formation of  nanosized powder. Spherical, nanosized particles of metals (Cu, Ag, Au, Co were produced with new and improved physical and chemical characteristics at the IME, RWTH Aachen University. The high costs associated with small quantities of produced nanosized particles represent a limitation of the USP-method. Therefore, scale up of the ultrasonic spray pyrolysis was performed as a final target in the synthesis of nanosized powder.

  11. Physical properties of the arctic summer aerosol particles in relation to sources at Ny-Alesund, Svalbard

    Indian Academy of Sciences (India)

    C G Deshpande; A K Kamra

    2014-02-01

    Measurements of the number concentration and size distribution of aerosol particles in the size range of 0.5–20 m diameter were made with an aerodynamic particle sizer at an Arctic site at Ny-Alesund, Svalbard in August–September 2007 during the International Polar Year 2007–2008. Data are analyzed to study the aerosol number concentration–wind speed relationships. The sea-salt particles of marine origin generated within the Arctic circle are identified as the main source of the Arctic summer aerosols. Total number concentration of aerosol particles increases with increase in wind speed, the increase being more when winds from open leads over the oceanic sector are reaching the station as compared to when winds from pack ice in other directions are reaching the station. The larger increase with winds from the oceanic sector is attributed to the enhanced bubble-breaking activity and increased entrainment of dimethyl sulphide particles at the sea surface. Although, the increase in total aerosol number concentration associated with the winds from the oceanic sector is spread over the whole range of particle sizes, the increase in coarse mode particles is more prominent than that in the accumulation mode particles. The age of airmass over pack ice is also an important factor to determine the aerosol concentration over the Arctic region. The process of rainout/washout of the aerosol particles due to drizzle/snowfall is an effective sink mechanism in the Arctic environment. The aerosol particle concentration starts decreasing within a few minutes from the start of these events but requires a few hours to restore to the normal background aerosol level after the end of event.

  12. Origin of Synthetic Particles in Honeys

    Directory of Open Access Journals (Sweden)

    Liebezeit Gerd

    2015-06-01

    Full Text Available A total of 47 honeys and 22 flowering plants was analysed for their load of synthetic fibres and fragments. In all samples investigated foreign particles were found. These include also black carbon particles which were not enumerated. Fibres and fragments ranged from 10 to 336 kg-1 and 2 to 82 kg-1 honey, respectively. The data of the flowering plants analysed indicate that a major proportion of the particle load may originate from external sources, i.e. these particles are brought into the beehive by the worker bees during nectar collection.

  13. Accelerated simulation of stochastic particle removal processes in particle-resolved aerosol models

    Science.gov (United States)

    Curtis, J. H.; Michelotti, M. D.; Riemer, N.; Heath, M. T.; West, M.

    2016-10-01

    Stochastic particle-resolved methods have proven useful for simulating multi-dimensional systems such as composition-resolved aerosol size distributions. While particle-resolved methods have substantial benefits for highly detailed simulations, these techniques suffer from high computational cost, motivating efforts to improve their algorithmic efficiency. Here we formulate an algorithm for accelerating particle removal processes by aggregating particles of similar size into bins. We present the Binned Algorithm for particle removal processes and analyze its performance with application to the atmospherically relevant process of aerosol dry deposition. We show that the Binned Algorithm can dramatically improve the efficiency of particle removals, particularly for low removal rates, and that computational cost is reduced without introducing additional error. In simulations of aerosol particle removal by dry deposition in atmospherically relevant conditions, we demonstrate about 50-times increase in algorithm efficiency.

  14. Source apportionment of single aerosol particles in the atmosphere of Shanghai city

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A nuclear microprobe with high spatial resolution and high analyti cal sensitivity was applied to analyze atmospheric aerosol at five monitoring sites in Shanghai city. Meantime, a new pattern recognition technique, which used the micro PIXE spectrum of a single aerosol particle as its fingerprint, was developed to identify the origin of the particle. The results showed that the major contributors to the at mosphere pollution were soil dust (31.6%), building dust (30.8%), and the next were vehicle exhaust (13.7%), metallurgic industry excrements (5.6%), oil combustion (5%) and coal combustion (2.3%). Besides these, about 10% of the particles could not be identified. Based on the cluster analysis of these particles, they could be divided into eight groups. By inference, they might belong to some sub-pollution sources from soil dust, building dust and metallurgic industry excrements. Moreover, some new pollution sources from tyres and chemical plants were also revealed.

  15. Selection of quasi-monodisperse super-micron aerosol particles

    Science.gov (United States)

    Rösch, Michael; Pfeifer, Sascha; Wiedensohler, Alfred; Stratmann, Frank

    2014-05-01

    Size-segregated quasi monodisperse particles are essential for e.g. fundamental research concerning cloud microphysical processes. Commonly a DMA (Differential Mobility Analyzer) is used to produce quasi-monodisperse submicron particles. Thereto first, polydisperse aerosol particles are bipolarly charged by a neutralizer, and then selected according to their electrical mobility with the DMA [Knutson et al. 1975]. Selecting a certain electrical mobility with a DMA results in a particle size distribution, which contains singly charged particles as well as undesired multiply charged larger particles. Often these larger particles need to either be removed from the generated aerosol or their signals have to be corrected for in the data inversion and interpretation process. This problem becomes even more serious when considering super-micron particles. Here we will present two different techniques for generating quasi-monodisperse super-micron aerosol particles with no or only an insignificant number of larger sized particles being present. First, we use a combination of a cyclone with adjustable aerodynamic cut-off diameter and our custom-built Maxi-DMA [Raddatz et al. 2013]. The cyclone removes particles larger than the desired ones prior to mobility selection with the DMA. This results in a reduction of the number of multiply charged particles of up to 99.8%. Second, we utilize a new combination of cyclone and PCVI (Pumped Counterflow Virtual Impactor), which is based on purely inertial separation and avoids particle charging. The PCVI instrument was previously described by Boulter et al. (2006) and Kulkarni et al. (2011). With our two setups we are able to produce quasi-monodisperse aerosol particles in the diameter range from 0.5 to 4.4 µm without a significant number of larger undesired particles being present. Acknowledgements: This work was done within the framework of the DFG funded Ice Nucleation research UnIT (INUIT, FOR 1525) under WE 4722/1-1. References

  16. Single-particle characterization of the high-Arctic summertime aerosol

    Directory of Open Access Journals (Sweden)

    B. Sierau

    2014-07-01

    Full Text Available Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS. The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol–cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of

  17. Molecular Characterization of Brown Carbon in Biomass Burning Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Peng; Aiona, Paige K.; Li, Ying; Shiraiwa, Manabu; Laskin, Julia; Nizkorodov, Sergey A.; Laskin, Alexander

    2016-11-01

    Emissions from biomass burning are a significant source of brown carbon (BrC) in the atmosphere. In this study, we investigate the molecular composition of freshly-emitted biomass burning organic aerosol (BBOA) samples collected during test burns of selected biomass fuels: sawgrass, peat, ponderosa pine, and black spruce. We characterize individual BrC chromophores present in these samples using high performance liquid chromatography coupled to a photodiode array detector and a high-resolution mass spectrometer. We demonstrate that both the overall BrC absorption and the chemical composition of light-absorbing compounds depend significantly on the type of biomass fuels and burning conditions. Common BrC chromophores in the selected BBOA samples include nitro-aromatics, polycyclic aromatic hydrocarbon derivatives, and polyphenols spanning a wide range of molecular weights, structures, and light absorption properties. A number of biofuel-specific BrC chromophores are observed, indicating that some of them may be used as potential markers of BrC originating from different biomass burning sources. On average, ~50% of the light absorption above 300 nm can be attributed to a limited number of strong BrC chromophores, which may serve as representative light-absorbing species for studying atmospheric processing of BrC aerosol. The absorption coefficients of BBOA are affected by solar photolysis. Specifically, under typical atmospheric conditions, the 300 nm absorbance decays with a half-life of 16 hours. A “molecular corridors” analysis of the BBOA volatility distribution suggests that many BrC compounds in the fresh BBOA have low volatility (<1 g m-1) and will be retained in the particle phase under atmospherically relevant conditions.

  18. Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign in Värriö field station

    Directory of Open Access Journals (Sweden)

    T. M. Ruuskanen

    2007-01-01

    Full Text Available The LAPBIAT measurement campaign took place in the SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the measurement campaign, concentrations and fluxes of aerosol particles, air ions and trace gases, paying special attention to an aerosol particle formation event broken by a polluted air mass approaching from industrial areas of Kola Peninsula, Russia. Aerosol particle number flux measurements show strong downward fluxes during that time. Concentrations of coarse aerosol particles were high for 1–2 days before the nucleation event (i.e. 28–29 April, very low immediately before and during the observed aerosol particle formation event (30 April and increased moderately from the moment of sudden break of the event. In general particle deposition measurements based on snow samples show the same changes. Measurements of the mobility distribution of air ions showed elevated concentrations of intermediate air ions during the particle formation event. We estimated the growth rates in the nucleation mode size range. For particles <10 nm, the growth rate increases with size on 30 April. Dispersion modelling made with model SILAM support the conclusion that the nucleation event was interrupted by an outbreak of sulphate-rich air mass in the evening of 30 April that originated from the industry at Kola Peninsula, Russia. The results of this campaign highlight the need for detailed research in atmospheric transport of air constituents for understanding the aerosol dynamics.

  19. Mixing properties of individual submicrometer aerosol particles in Vienna

    Science.gov (United States)

    Okada, Kikuo; Hitzenberger, Regina M.

    Individual aerosol particles were collected on 5 days with different meteorological conditions in March, April and June 1991 in the urban atmosphere of Vienna in Austria. The samples collected with an impactor were examined by electron microscopy. The mixing properties of submicrometer aerosol particles with radii between 0.1 and 1 μm were studied by using the dialysis (extraction) of water-soluble material. The averaged results showed that more than 85% of particles with radii between 0.1 and 0.7 μm were hygroscopic. However, more than 50% of particles with radii larger than 0.2 μm were mixed particles (hygroscopic particles with water-insoluble inclusions), and they were dominant (80%) in the size range 0.5-0.7 μm radius. The results also showed that the number proportion of mixed particles increased with increasing radius and the abundance increased with increasing particle loading in the atmosphere. The volume fraction of water-soluble material ( ɛ) in mixed particles tended to decrease with increasing radius, implying the formation of mixed particles by heterogeneous processes such as condensation and/or surface reaction. Some results of elemental composition in individual particles analyzed with an energy-dispersive X-ray (EDX) analyzer equipped with an electron microscope are also presented in this paper.

  20. Improved identification of primary biological aerosol particles using single particle mass spectrometry

    OpenAIRE

    Zawadowicz, Maria A.; Froyd, Karl D.; Murphy, Daniel M.; Cziczo, Daniel J.

    2016-01-01

    Measurements of primary biological aerosol particles, especially at altitudes relevant to cloud formation, are scarce. Single particle mass spectrometry (SPMS) has been used to probe aerosol chemical composition from ground and aircraft for over 20 years. Here we develop a method for identifying bioaerosols using SPMS. We show that identification of bioaerosol using SPMS is complicated because phosphorus-bearing mineral dust and phosphorus-rich combustion by-products such as fly ash produce m...

  1. Organic aerosol mixing observed by single-particle mass spectrometry.

    Science.gov (United States)

    Robinson, Ellis Shipley; Saleh, Rawad; Donahue, Neil M

    2013-12-27

    We present direct measurements of mixing between separately prepared organic aerosol populations in a smog chamber using single-particle mass spectra from the high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Docosane and docosane-d46 (22 carbon linear solid alkane) did not show any signs of mixing, but squalane and squalane-d62 (30 carbon branched liquid alkane) mixed on the time scale expected from a condensational-mixing model. Docosane and docosane-d46 were driven to mix when the chamber temperature was elevated above the melting point for docosane. Docosane vapors were shown to mix into squalane-d62, but not the other way around. These results are consistent with low diffusivity in the solid phase of docosane particles. We performed mixing experiments on secondary organic aerosol (SOA) surrogate systems finding that SOA derived from toluene-d8 (a surrogate for anthropogenic SOA (aSOA)) does not mix into squalane (a surrogate for hydrophobic primary organic aerosol (POA)) but does mix into SOA derived from α-pinene (biogenic SOA (bSOA) surrogate). For the aSOA/POA, the volatility of either aerosol does not limit gas-phase diffusion, indicating that the two particle populations do not mix simply because they are immiscible. In the aSOA/bSOA system, the presence of toluene-d8-derived SOA molecules in the α-pinene-derived SOA provides evidence that the diffusion coefficient in α-pinene-derived SOA is high enough for mixing on the time scale of 1 min. The observations from all of these mixing experiments are generally invisible to bulk aerosol composition measurements but are made possible with single-particle composition data.

  2. Sea-spray aerosol particles generated in the surf zone

    NARCIS (Netherlands)

    Eijk, A.M.J. van; Kusmierczyk‐Michulec, J.T.; Francius, M.J.; Tedeschi, G.; Piazzola,J.; Merritt, D.L.; Fontana, J.D.

    2011-01-01

    To assess the properties of aerosol particles generated over the surf zone, two experiments were held at the pier of Scripps Institution of Oceanography (SIO), La Jolla CA, and at the pier of the U.S. Army Corps of Engineers Field Research Facility (FRF) in Duck NC. On both sites concentrations of s

  3. 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.

  4. Light Absorption of Biogenic Aerosol Particles in Amazonia

    Science.gov (United States)

    Holanda, B. A.; Artaxo, P.; Ferreira De Brito, J.; Barbosa, H. M.; Andreae, M. O.; Saturno, J.; Pöhlker, C.; Holben, B. N.; Schafer, J.

    2014-12-01

    Aerosol absorption is a key issue in proper calculation of aerosol radiative forcing. Especially in the tropics with the dominance of natural biogenic aerosol and brown carbon, the so called anomalous absorption is of particular interest. A special experiment was designed to study the wavelength dependence of aerosol absorption for PM2.5 as well as for PM10 particles in the wet season in Central Amazonia. Aerosol analysis occurred from May to August 2014, in the ZF2 ecological reservation, situated at about 55 km North of Manaus in very pristine conditions Two 7 wavelengths AE33 Aethalometers were deployed measuring in parallel, but with a PM2.5 and PM10 inlets. Two MAAP (Multiangle Aerosol Absorption Photometer) were operated in parallel with the AE33 exactly at the same PM2.5 and PM10 inlets. Organic and elemental carbon was analyzed using collection with quartz filters and analysis using a Sunset OC/EC analyzer. Aerosol light scattering for 3 wavelengths was measured using Air Photon and TSI Nephelometers. Aerosol size distribution was measured with one TSI SMPS and a GRIMM OPC to have the size range from 10 nm to 10 micrometers. Particles were measured under dry conditions using diffusion dryers. Aerosol optical depth and absorption was also measured with an AERONET sunphotometer operated close to the site. As the experiment was run in the wet season, very low equivalent black carbon (EBC) were measured, with average concentrations around 50 ng/m³ during May, increasing to 130 ng/m³ in June and July. The measurements adjusted for similar wavelengths shows excellent agreement between the MAAP and AE33 for both inlets (PM2.5 and PM10). It was not possible statistically infer absorption from the coarse mode biogenic particles, since the absorption was completely dominated by fine mode particles. AERONET measurements shows very low values of AOD, at 0.17 at 500 nm and 0.13 at 870 nm, with very low absorption AOD values at 0.00086 at 676 nm and 0.0068 at 872 nm

  5. Ice Nucleation Activity of Various Agricultural Soil Dust Aerosol Particles

    Science.gov (United States)

    Schiebel, Thea; Höhler, Kristina; Funk, Roger; Hill, Thomas C. J.; Levin, Ezra J. T.; Nadolny, Jens; Steinke, Isabelle; Suski, Kaitlyn J.; Ullrich, Romy; Wagner, Robert; Weber, Ines; DeMott, Paul J.; Möhler, Ottmar

    2016-04-01

    Recent investigations at the cloud simulation chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere) suggest that agricultural soil dust has an ice nucleation ability that is enhanced up to a factor of 10 compared to desert dust, especially at temperatures above -26 °C (Steinke et al., in preparation for submission). This enhancement might be caused by the contribution of very ice-active biological particles. In addition, soil dust aerosol particles often contain a considerably higher amount of organic matter compared to desert dust particles. To test agricultural soil dust as a source of ice nucleating particles, especially for ice formation in warm clouds, we conducted a series of laboratory measurements with different soil dust samples to extend the existing AIDA dataset. The AIDA has a volume of 84 m3 and operates under atmospherically relevant conditions over wide ranges of temperature, pressure and humidity. By controlled adiabatic expansions, the ascent of an air parcel in the troposphere can be simulated. As a supplement to the AIDA facility, we use the INKA (Ice Nucleation Instrument of the KArlsruhe Institute of Technology) continuous flow diffusion chamber based on the design by Rogers (1988) to expose the sampled aerosol particles to a continuously increasing saturation ratio by keeping the aerosol temperature constant. For our experiments, soil dust was dry dispersed into the AIDA vessel. First, fast saturation ratio scans at different temperatures were performed with INKA, sampling soil dust aerosol particles directly from the AIDA vessel. Then, we conducted the AIDA expansion experiment starting at a preset temperature. The combination of these two different methods provides a robust data set on the temperature-dependent ice activity of various agriculture soil dust aerosol particles with a special focus on relatively high temperatures. In addition, to extend the data set, we investigated the role of biological and organic matter in more

  6. Single particle multichannel bio-aerosol fluorescence sensor

    Science.gov (United States)

    Kaye, P. H.; Stanley, W. R.; Hirst, E.; Foot, E. V.; Baxter, K. L.; Barrington, S. J.

    2005-05-01

    We describe a prototype low-cost multi-channel aerosol fluorescence sensor designed for unattended deployment in medium to large area bio-aerosol detection networks. Individual airborne particles down to ~1μm in size are detected and sized by measurement of light scattered from a continuous-wave diode laser (660nm). This scatter signal is then used to trigger the sequential firing of two xenon sources which irradiate the particle with UV pulses at ~280 nm and ~370 nm, optimal for excitation of bio-fluorophores tryptophan and NADH (nicotinamide adenine dinucleotide) respectively. For each excitation wavelength, fluorescence is detected across two bands embracing the peak emissions of the same bio-fluorophores. Current measurement rates are up to ~125 particles/s, corresponding to all particles for concentrations up to 1.3 x 104 particles/l. Developments to increase this to ~500 particles/s are in hand. Device sensitivity is illustrated in preliminary data recorded from aerosols of E.coli, BG spores, and a variety of non-biological materials.

  7. Visualizing aerosol-particle injection for diffractive-imaging experiments

    CERN Document Server

    Awel, Salah; Eckerskorn, Niko; Wiedorn, Max; Horke, Daniel A; Rode, Andrei V; Küpper, Jochen; Chapman, Henry N

    2015-01-01

    Delivering sub-micrometer particles to an intense x-ray focus is a crucial aspect of single-particle diffractive-imaging experiments at x-ray free-electron lasers. Enabling direct visualization of sub-micrometer aerosol particle streams without interfering with the operation of the particle injector can greatly improve the overall efficiency of single-particle imaging experiments by reducing the amount of time and sample consumed during measurements. We have developed in-situ non-destructive imaging diagnostics to aid real-time particle injector optimization and x-ray/particle-beam alignment, based on laser illumination schemes and fast imaging detectors. Our diagnostics are constructed to provide a non-invasive rapid feedback on injector performance during measurements, and have been demonstrated during diffraction measurements at the FLASH free-electron laser.

  8. 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.

  9. 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

  10. Seasonal variations in aerosol particle composition at the puy-de-Dôme research station

    Directory of Open Access Journals (Sweden)

    E. J. Freney

    2011-10-01

    Full Text Available Detailed investigations of the chemical and microphysical properties of atmospheric aerosol particles were performed at the puy-de-Dôme (pdD research station (1465 m in autumn (September and October 2008, winter (February and March 2009, and summer (June 2010 using a Time-of-Flight Aerosol Mass Spectrometer. Over the three campaigns, the average mass concentrations of the non-refractory submicron particles ranged from 10 μg m−3 up to 27 μg m−3. Highest nitrate and ammonium mass concentrations were measured during the winter and during periods when marine modified airmasses were arriving at the site, whereas highest concentrations of organic particles were measured during the summer and during periods when continental airmasses arrived at the site. The measurements reported in this paper show that atmospheric particle composition is strongly influenced by both the season and the origin of the airmass. The total organic mass spectra were analysed using positive matrix factorisation to separate individual organic components contributing to the overall organic particle mass concentrations. These organic components include a low volatility oxygenated organic aerosol particle (LV-OOA and a semi-volatile organic aerosol particle (SV-OOA. Correlations of the LV-OOA components with fragments of m/z 60 and m/z 73 (mass spectral markers of wood burning during the winter campaign suggest that wintertime LV-OOA are related to aged biomass burning emissions, whereas organic aerosol particles measured during the summer are likely linked to biogenic sources. Equivalent potential temperature calculations, gas-phase, and LIDAR measurements define whether the research site is in the planetary boundary layer (PBL or in the free troposphere (FT/residual layer (RL. We observe that SV-OOA and nitrate particles are associated with air masses arriving from the PBL where as particle composition measured from RL/FT airmasses

  11. Sources and characteristics of fine particles over the Yellow Sea and Bohai Sea using online single particle aerosol mass spectrometer.

    Science.gov (United States)

    Fu, Huaiyu; Zheng, Mei; Yan, Caiqing; Li, Xiaoying; Gao, Huiwang; Yao, Xiaohong; Guo, Zhigang; Zhang, Yuanhang

    2015-03-01

    Marine aerosols over the East China Seas are heavily polluted by continental sources. During the Chinese Comprehensive Ocean Experiment in November 2012, size and mass spectra of individual atmospheric particles in the size range from 0.2 to 2.0 μm were measured on board by a single particle aerosol mass spectrometer (SPAMS). The average hourly particle number (PN) was around 4560±3240 in the South Yellow Sea (SYS), 2900±3970 in the North Yellow Sea (NYS), and 1700±2220 in the Bohai Sea (BS). PN in NYS and BS varied greatly over 3 orders of magnitude, while that in SYS varied slightly. The size distributions were fitted with two log-normal modes. Accumulation mode dominated in NYS and BS, especially during episodic periods. Coarse mode particles played an important role in SYS. Particles were classified using an adaptive resonance theory based neural network algorithm (ART-2a). Six particle types were identified with secondary-containing, aged sea-salt, soot-like, biomass burning, fresh sea-salt, and lead-containing particles accounting for 32%, 21%, 18%, 16%, 4%, and 3% of total PN, respectively. Aerosols in BS were relatively enriched in particles from anthropogenic sources compared to SYS, probably due to emissions from more developed upwind regions and indicating stronger influence of continental outflow on marine environment. Variation of source types depended mainly on origins of transported air masses. This study examined rapid changes in PN, size distribution and source types of fine particles in marine atmospheres. It also demonstrated the effectiveness of high-time-resolution source apportionment by ART-2a.

  12. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

    atmospheric conditions using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear and significant contribution from ion induced nucleation and consider this to be an unambiguous observation of the ion-effect on aerosol nucleation using a particle beam under conditions not far......The effect of ions in aerosol nucleation is a subject where much remains to be discovered. That ions can enhance nucleation has been shown by theory, observations, and experiments. However, the exact mechanism still remains to be determined. One question is if the nature of the ionization affects...... the nucleation. This is an essential question since many experiments have been performed using radioactive sources that ionize differently than the cosmic rays which are responsible for the majority of atmospheric ionization. Here we report on an experimental study of sulphuric acid aerosol nucleation under near...

  13. Chemical properties and origin of dust aerosols in Beijing during springtime

    Institute of Scientific and Technical Information of China (English)

    Renjian Zhang; Zhiwei Han; Tiantao Cheng; Jun Tao

    2009-01-01

    Ground observation of dust aerosols was conducted in Beijing in the spring of 2005 in order to investigate the element composition and origin of mineral dust. Mass concentrations of most mineral elements of particles increased during dust events. Mineral elements were predominant in the sums of total element loadings in both dusty and non-dusty days. Mg, Si, Fe, Al or Ti can be used as an indicator of dust outflow; Cl can be viewed as an evidence of dust particles mixing with anthropogenic emissions. Mineral and pollutant elements showed a bimodal mass particle-size distribution (MSD) in non-dusty days, and a trimodal distribution in dusty days, but their peak concentrations fell in different size stages. Zn and S were mainly enriched in fine particles, whereas Cl was enriched in medium particles, but most mineral elements and Cu were enriched in coarse particles. Mineral elements were dominated by crustal material in dusty even non-dusty days, but pollutant elements were from non-crustal material including local and remote sources. Back trajectory analysis indicated that dust particles in Beijing mainly originated from the Gobi and desert regions of Mongolian and northern China.

  14. Particle size distribution and behavior of sulfate aerosols in a coastal region

    Energy Technology Data Exchange (ETDEWEB)

    Fujimura, M.; Hashimoto, Y.

    1979-01-01

    To obtain fundamental knowledge about sulfate aerosols, a field research was conducted in a coastal region distant from industrial pollution sources. The aerosol samples were analyzed for some elements, sulfate and ammonium ions. Sulfate was determined by the turbidimetry with 2-aminoperimidine, and ammonium was by the colorimetry of indophenol method. Trace elements with short-lived nuclides were analyzed by instrumental neutron activation analysis. The mass-size distribution curve of total aerosols was the general bimodal pattern, although the concentration level was very low. Most of sulfate and ammonium salts were distributed in the fine particle range less than 2 microns in aerodynamic diameter, but sulfate had another peak, thought to be of maritime origin, in the coarse particle range. Nevertheless, many fine sulfate particles that had been produced secondarily in the atmosphere were found in such a less polluted coastal region. The change of the sulfate concentrations obtained by the two-stage Andersen type sampler showed a correlation with the humidity. This may suggest that the formation of sulfate aerosols from sulfur dioxide could be related to a catalytic oxidation process in water drops.

  15. Transition metal associations with primary biological particles in sea spray aerosol generated in a wave channel.

    Science.gov (United States)

    Guasco, Timothy L; Cuadra-Rodriguez, Luis A; Pedler, Byron E; Ault, Andrew P; Collins, Douglas B; Zhao, Defeng; Kim, Michelle J; Ruppel, Matthew J; Wilson, Scott C; Pomeroy, Robert S; Grassian, Vicki H; Azam, Farooq; Bertram, Timothy H; Prather, Kimberly A

    2014-01-21

    In the ocean, breaking waves generate air bubbles which burst at the surface and eject sea spray aerosol (SSA), consisting of sea salt, biogenic organic species, and primary biological aerosol particles (PBAP). Our overall understanding of atmospheric biological particles of marine origin remains poor. Here, we perform a control experiment, using an aerosol time-of-flight mass spectrometer to measure the mass spectral signatures of individual particles generated by bubbling a salt solution before and after addition of heterotrophic marine bacteria. Upon addition of bacteria, an immediate increase occurs in the fraction of individual particle mass spectra containing magnesium, organic nitrogen, and phosphate marker ions. These biological signatures are consistent with 21% of the supermicrometer SSA particles generated in a previous study using breaking waves in an ocean-atmosphere wave channel. Interestingly, the wave flume mass spectral signatures also contain metal ions including silver, iron, and chromium. The nascent SSA bioparticles produced in the wave channel are hypothesized to be as follows: (1) whole or fragmented bacterial cells which bioaccumulated metals and/or (2) bacteria-derived colloids or biofilms which adhered to the metals. This study highlights the potential for transition metals, in combination with specific biomarkers, to serve as unique indicators for the presence of marine PBAP, especially in metal-impacted coastal regions.

  16. Neural networks for aerosol particles characterization

    Science.gov (United States)

    Berdnik, V. V.; Loiko, V. A.

    2016-11-01

    Multilayer perceptron neural networks with one, two and three inputs are built to retrieve parameters of spherical homogeneous nonabsorbing particle. The refractive index ranges from 1.3 to 1.7; particle radius ranges from 0.251 μm to 56.234 μm. The logarithms of the scattered radiation intensity are used as input signals. The problem of the most informative scattering angles selection is elucidated. It is shown that polychromatic illumination helps one to increase significantly the retrieval accuracy. In the absence of measurement errors relative error of radius retrieval by the neural network with three inputs is 0.54%, relative error of the refractive index retrieval is 0.84%. The effect of measurement errors on the result of retrieval is simulated.

  17. Glyoxal and Methylglyoxal in Atlantic Seawater and marine Aerosol Particles

    Science.gov (United States)

    van Pinxteren, Manuela; Herrmann, Hartmut

    2014-05-01

    The two α-dicarbonyls glyoxal (CHOCHO; GLY) and methylglyoxal (CH3COCHO; MGLY) have attracted increasing attention over the past years because of their potential role in secondary organic aerosol formation. Recently Sinreich et al. (2010) suggested the open ocean as an important (so far unknown) source for GLY in the atmosphere. To date, there are few available field data of these compounds in the marine area. In this study we present measurements of GLY and MGLY in seawater and marine aerosol particles sampled during a transatlantic Polarstern cruise in spring 2011. In seawater we especially investigated the sea surface microlayer (sampled with the glass plate technique) as it is the direct interface between ocean and atmosphere. Analytical measurements were based on derivatisation with o-(2,3,4,5,6-Pentafluorobenzyl)-hydroxylamine reagent, solvent extraction and GC-MS (SIM) analysis. The results show that GLY and MGLY are present in the sea surface microlayer of the ocean and corresponding bulkwater with average concentrations of 228 ng L-1 (GLY) and 196 ng L-1 (MGLY). Significant enrichment (factor of 4) of GLY and MGLY in the sea surface microlayer was found implying photochemical production of the two carbonyls though a clear connection to global radiation was not observed. On aerosol particles, both carbonyls were detected (average concentration 0.2 ng m-3) and are strongly connected to each other, suggesting similar formation mechanisms. Both carbonyls show a very good correlation with particulate oxalate, supporting the idea of a secondary formation of oxalic acid via GLY and MGLY. A slight correlation of the two carbonyls in the sea surface microlayer and in the aerosol particles was found at co-located sampling areas. In summary, the results of GLY and MGLY in marine aerosol particles and in the oceanic water give first insights towards interaction processes of these alpha dicarbonyls between ocean and atmosphere (van Pinxteren and Herrmann (2013

  18. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

    2011-01-01

    We have studied sulfuric acid aerosol nucleation in an atmospheric pressure reaction chamber using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear contribution from ion-induced nucleation and consider this to be the first unambiguous observation of the ion......-effect on aerosol nucleation using a particle beam under conditions that resemble the Earth's atmosphere. By comparison with ionization using a gamma source we further show that the nature of the ionizing particles is not important for the ion-induced component of the nucleation. This implies that inexpensive...... ionization sources - as opposed to expensive accelerator beams - can be used for investigations of ion-induced nucleation....

  19. 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.

  20. Virtual Impactor for Sub-micron Aerosol Particles

    Science.gov (United States)

    Bolshakov, A. A.; Strawa, A. W.; Hallar, A. G.

    2005-12-01

    The objective of a virtual impactor is to separate out the larger particles in a flow from the smaller particles in such a way that both sizes of particles are available for sampling. A jet of particle-laden air is accelerated toward a collection probe so that a small gap exists between the acceleration nozzle and the probe. A vacuum is applied to deflect a major portion of the airstream away form the collection probe. Particles larger than a certain size have sufficient momentum so that they cross the deflected streamlines and enter the collection probe, whereas smaller particles follow the deflected streamlines. The result is that the collection probe will contain a higher concentration of larger particles than is in the initial airstream. Typically, virtual impactors are high-flow devices used to separate out particles greater than several microns in diameter. We have developed a special virtual impactor to concentrate aerosol particles of diameters between 0.5 to 1 micron for the purpose of calibrating the optical cavity ring-down instrument [1]. No similar virtual impactors are commercially available. In our design, we have exploited considerations described earlier [2-4]. Performance of our virtual impactor was evaluated in an experimental set-up using TSI 3076 nebulizer and TSI 3936 scanning mobility particle size spectrometer. Under experimental conditions optimized for the best performance of the virtual impactor, we were able to concentrate the 700-nm polystyrene particles no less than 15-fold. However, under experimental conditions optimized for calibrating our cavity ring-down instrument, a concentration factor attainable was from 4 to 5. During calibration experiments, maximum realized particle number densities were 190, 300 and 1600 cm-3 for the 900-nm, 700-nm and 500-nm spheres, respectively. This paper discusses the design of the impactor and laboratory studies verifying its performance. References: 1. A.W. Strawa, R. Castaneda, T. Owano, D.S. Baer

  1. Composition and Particle Size Retrievals for Homogeneous Binary Aerosols

    Science.gov (United States)

    Niedziela, R. F.; Argon, P.; Bejcek, L.

    2014-12-01

    Tropospheric aerosols have widely varying compositions, shapes, and sizes. The ability to measure these physical characteristics, coupled with knowledge about their optical properties, can provide insight as to how these particles might participate in atmospheric processes, including their interaction with light. Over the past several years, our laboratory has been involved in developing methods to determine basic physical properties of laboratory-generated particles based on the analysis of infrared extinction spectra of multi-component aerosols. Here we report the results of a complete study on the applicability of well-known refractive index mixing rules to homogeneous binary liquid organic aerosols in an effort to yield in situ measurements of particle size and composition. In particular, we present results for terpenoid (carvone/nopinone) and long-chain hydrocarbon (squalane/squalene) mixtures. The included image shows model carvone/nopinone extinction spectra that were computed using the Lorentz-Lorenz mixing rule on complex refractive index data for the pure components.

  2. A role of aerosol particles in forming urban skyglow and skyglow from distant cities

    Science.gov (United States)

    Kocifaj, Miroslav; Kómar, Ladislav

    2016-05-01

    Aerosol particles may represent the largest uncertainty about skyglow change in many locations under clear-sky conditions. This is because aerosols are ubiquitous in the atmosphere and influence the ground-reaching radiation in different ways depending on their concentrations, origins, shapes, sizes, and compositions. Large particles tend to scatter in Fraunhofer diffraction regime, while small particles can be treated in terms of Rayleigh formalism. However, the role of particle microphysics in forming the skyglow still remains poorly quantified. We have shown in this paper that the chemistry is somehow important for backscattering from large particles that otherwise work as efficient attenuators of light pollution if composed of absorbing materials. The contribution of large particles to the urban skyglow diminishes as they become more spherical in shape. The intensity of backscattering from non-absorbing particles is more-or-less linearly decreasing function of particle radius even if number size distribution is inversely proportional to the fourth power of particle radius. This is due to single particle backscattering that generally increases steeply as the particle radius approaches large values. Forward scattering depends on the particle shape but is independent of the material composition, thus allowing for a simplistic analytical model of skyglow from distant cities. The model we have developed is based on mean value theorem for integrals and incorporates the parametrizable Garstang's emission pattern, intensity decay along optical beam path, and near-forward scattering in an atmospheric environment. Such model can be used by modellers and experimentalists for rapid estimation of skyglow from distant light sources.

  3. Oxalate metal complexes in aerosol particles: implications for the hygroscopicity of oxalate-containing particles

    Directory of Open Access Journals (Sweden)

    T. Furukawa

    2011-05-01

    Full Text Available Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to weaken the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA play an important role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is an important component of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca and zinc (Zn in aerosols collected at Tsukuba in Japan. Size-fractionated aerosol samples were collected for this purpose using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm were present as Ca and Zn oxalate complexes, respectively. Oxalic acid is hygroscopic and can thus increase the CCN activity of aerosol particles, while complexes with various polyvalent metal ions such as Ca and Zn are not hygroscopic, which cannot contribute to the increase of the CCN activity of aerosols. Based on the concentrations of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not always increase the hygroscopicity of aerosols in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is advisable that the cooling effect of organic aerosols should be estimated by including the

  4. Physical and chemical properties of pollution aerosol particles transported from North America to Greenland as measured during the POLARCAT summer campaign

    Directory of Open Access Journals (Sweden)

    B. Quennehen

    2011-04-01

    Full Text Available Within the framework of the POLARCAT-France campaign, aerosol physical, chemical and optical properties over Greenland were measured onboard the French ATR-42 research aircraft. The Lagrangian particle dispersion model FLEXPART was used to determine air mass origins. The study focuses particularly on the characterization of air masses transported from the North American continent. Air masses that picked up emissions from Canadian and Alaskan boreal forest fires as well as from the cities on the American east coast were identified and selected for a detailed study. Measurements of CO concentrations, aerosol chemical composition, aerosol size distributions, aerosol volatile fractions and aerosol light absorption (mainly from black carbon are used in order to study the relationship between CO enhancement, ageing of the air masses, aerosol particle concentrations and size distributions. Aerosol size distributions are in good agreement with previous studies, even though, wet scavenging potentially occurred along the pathway between the emission sources and Greenland leading to lower concentrations in the aerosol accumulation mode. The measured aerosol size distributions show a significant enhancement of Aitken mode particles. It is demonstrated that the Aitken mode is largely composed of black carbon, while the accumulation mode is more dominated by organics, as deduced from aerosol mass spectrometric AMS and aerosol volatility measurements. Overall, during the campaign rather small amounts of black carbon from the North American continent were transported towards Greenland. An important finding given the potential climate impacts of black carbon in the Arctic.

  5. Origin Of Aerosols Above Neuchatel, Switzerland, In August 2003

    Energy Technology Data Exchange (ETDEWEB)

    Furger, M.; Mitev, V. [Observatoire de Neuchatel (Switzerland); Matthey, R. [Observatoire de Neuchatel (Switzerland); Collaud-Coen, M. [MeteoSwiss (Switzerland); Weingartner, E.

    2005-03-01

    Aerosols may be transported over continental scale distances. Lidar-detected elevated aerosol layers in the summer of 2003 may have been influenced by Sahara dust rather than forest fire plumes. (author)

  6. Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

    2016-09-15

    Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

  7. Aerosol Particles From Tropical Cirrus Clouds in the Lower Stratosphere

    Science.gov (United States)

    Kojima, T.; Buseck, P. R.; Wilson, J. C.; Reeves, J. M.

    2002-12-01

    Aerosol samples were collected from convective systems and cirrus layers over Florida during the July 2002 CRYSTAL-FACE Mission. Particles between 0.02 and 700 \\micron were deposited directly onto TEM grids. Here we report preliminary results of the TEM study of particles collected near and above the tropopause. Most particles are sulfate droplets that range from 0.8 to 5 \\micron in diameter on the TEM grids. All have a characteristic appearance that consists of a main central particle (0.3 -1 \\micron) surrounded by many smaller satellite droplets. Their appearance suggests that the droplets were sulfuric acid partially neutralized with ammonium at the time of collection, with ammonium sulfate and bisulfate constituting the central particles (Bigg, 1975, 1980). The degree of ammoniation in individual droplets, which is indicated by the size of central particles relative to satellite ring diameter, is fairly uniform. The ratio of central particle diameter to satellite ring diameter is generally around 0.3. Such ammoniated droplets with solid cores may be more efficient in nucleating cirrus than pure sulfuric acid droplets (Tabazadeh and Toon, 1998). Ammonium sulfate particles without satellites commonly coexist with the acid droplets. Minor particles consist of C-rich amorphous material, silicates, Na- and K-chlorides and sulfates, and Cr- and Ti-oxides. Some were coated with sulfate. Many of the C-rich particles contain significant amount of K, S, and O with lesser N. All silicate particles are flakes of clay minerals that have pseudohexagonal structures. They would work as effective ice nuclei (Pruppacher and Klett, 1997).

  8. Comparison of the DiSCmini aerosol monitor to a handheld condensation particle counter and a scanning mobility particle sizer for submicrometer sodium chloride and metal aerosols.

    Science.gov (United States)

    Mills, Jessica B; Park, Jae Hong; Peters, Thomas M

    2013-01-01

    We evaluated the robust, lightweight DiSCmini (DM) aerosol monitor for its ability to measure the concentration and mean diameter of submicrometer aerosols. Tests were conducted with monodispersed and polydispersed aerosols composed of two particle types (sodium chloride [NaCl] and spark-generated metal particles, which simulate particles found in welding fume) at three different steady-state concentration ranges (Low, 10(4) particles/cm(3)). Particle number concentration, lung deposited surface area (LDSA) concentration, and mean size measured with the DM were compared with those measured with reference instruments, a scanning mobility particle sizer (SMPS), and a handheld condensation particle counter (CPC). Particle number concentrations measured with the DM were within 16% of those measured by the CPC for polydispersed aerosols. Poorer agreement was observed for monodispersed aerosols (±35% for most tests and +101% for 300-nm NaCl). LDSA concentrations measured by the DM were 96% to 155% of those estimated with the SMPS. The geometric mean diameters measured with the DM were within 30% of those measured with the SMPS for monodispersed aerosols and within 25% for polydispersed aerosols (except for the case when the aerosol contained a substantial number of particles larger than 300 nm). The accuracy of the DM is reasonable for particles smaller than 300 nm, but caution should be exercised when particles larger than 300 nm are present. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resources: manufacturer-reported capabilities of instruments used, and information from the SMPS measurements for polydispersed test particles.].

  9. Morphology and Optical Properties of Mixed Aerosol Particles

    Science.gov (United States)

    Fard, Mehrnoush M.; Krieger, Ulrich; Rudich, Yinon; Marcolli, Claudia; Peter, Thomas

    2016-04-01

    Experiments and modeling studies have shown that deliquesced aerosols can exist not only as one-phase system containing organics, inorganic salts and water, but often as two-phase systems consisting of a predominantly organic and a predominantly inorganic aqueous phase (1,2). Recent laboratory studies conducted with model mixtures representing tropospheric aerosols (1,2,3), secondary organic aerosol (SOA) from smog chamber experiments (4), and field measurements (5) suggest that liquid-liquid phase separations (LLPS) is indeed a common phenomenon in mixed organic/ inorganic particles. During LLPS, particles may adopt different morphologies mainly core-shell and partially engulfed. A core-shell configuration will have consequences for heterogeneous chemistry and hygroscopicity and as a result will alter the optical properties of the particles in particular for organic phases containing absorbing molecules, e.g. brown carbon. The primary objective of this project is to establish a method for investigating the morphology of mixed inorganic and absorbing organic compounds of atmospheric relevance and study their radiative properties before, during, and after phase transitions mainly during LLPS. This will be the first study looking into the radiative effect of LLPS in detail. Our ternary model system consist of ammonium sulfate (AS)/ Polyethylene Glycol (PEG)/ and water (H2O). Carminic acid (CA) was added as a proxy for an absorbing organic compound to the system. The behavior of single droplets of above ternary mixture was monitored during relative humidity (RH) cycles using optical microscopy. The same ternary mixture particle was levitated in an electrodynamic balance (EDB) and the change in its absorption properties was measured at varying RH. In addition, Mie-code modeling is used to predict the absorption efficiency of the same ternary system and the result will be compared with the data obtained from EDB experiment. We also intend to determine the occurrence of

  10. Characterization of aerosol particle episodes in Finland caused by wildfires in Eastern Europe

    Directory of Open Access Journals (Sweden)

    J. V. Niemi

    2005-01-01

    Full Text Available We studied the sources, compositions and size distributions of aerosol particles during long-range transport (LRT PM2.5 episodes which occurred on 12–15 August, 26–28 August and 5–6 September 2002 in Finland. Backward air mass trajectories, satellite detections of fire areas and dispersion modelling results indicate that emissions from wildfires in Russia and other Eastern European countries arrived in Finland during these episodes. Elemental analyses using scanning electron microscopy (SEM coupled with energy dispersive X-ray microanalyses (EDX showed that the proportions of S-rich particles and agglomerates (agglomeration was caused partly by the sampling method used increased during the episodes, and they contained elevated fractions of K, indicating emissions from biomass burning. These aerosols were mixed with S-rich emissions from fossil fuel burning during transport since air masses came through polluted areas of Europe. Minor amounts of coarse Ca-rich particles were also brought by LRT during the episodes, and they probably originated from wildfires and/or from Estonian and Russian oil-shale-burning industrial areas. Ion chromatography analysis showed that concentrations of sulphate (SO42-, total nitrate (NO3-+HNO3(g and total ammonium (NH4++NH3(g increased during the episodes, but the ratio of the total amount of these ions to PM10 concentration decreased, indicating unusually high fractions of other chemical components. Particle number size distribution measurements with differential mobility particle sizer (DMPS revealed that concentrations of particles 90–500 nm increased during the episodes, while concentrations of particles smaller than 90 nm decreased. The reduction of the smallest particles was caused by suppressed new particle formation due to vapour and molecular cluster uptake of LRT particles. Our results show that emissions from wildfires in Russian and other Eastern European countries deteriorated air quality of

  11. Development of Laser-Based Handheld Aerosol Particle Counter

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang; LI Hui

    2005-01-01

    The JC-CA300 handheld Aerosol particle counter is designed and developed based on light scattering principle. The JC-CA300 counter is composed of optical sensor, DSP component and microprocessor unit. The hardware architecture is designed in compact style by SMT IC chips. The whole counter weight is less than 2 pounds. With 32K RAM space, the JC-CA300 can store 500 sampling records and support standard printer and communicate with a computer through RS232 interface. Based on experimental results, the main performance of JC-CA300 is better than that of the ARTI'S HHPC-6 instrument.

  12. Tropospheric aerosol scattering and absorption over Central Europe: a closure study for the dry particle state

    Directory of Open Access Journals (Sweden)

    N. Ma

    2013-10-01

    Full Text Available This work analyses optical properties of the dry tropospheric aerosol measured at the regional GAW observation site Melpitz in East Germany. For a continuous observation period between 2007 and 2010, we provide representative values of the dry-state scattering coefficient, the hemispheric backscattering coefficient, the absorption coefficient, single scattering albedo, and the Ångström exponent. Besides the direct measurement, the aerosol scattering coefficient was alternatively computed from experimental particle number size distributions using a Mie code. Within pre-defined limits, a closure could be achieved with the direct measurement. The achievement of closure implies that such calculations can be used as a high-level quality control measure for data sets involving multiple instrumentation. All dry optical properties showed significant annual variations, which were attributed to corresponding variations in the regional emission fluxes, the intensity of secondary particle formation, and the mixed layer height. Air mass classification showed that atmospheric stability is a major factor influencing the dry aerosol properties at the GAW station. In the cold season, temperature inversions limit the volume available for atmospheric mixing, so that the aerosol optical properties near the ground proved quite sensitive to the geographical origin of the air mass. In the warm season, when the atmosphere is usually well-mixed during day-time, considerably less variability was observed for the optical properties between different air masses. This work provides, on the basis of quality-checked in-situ measurements, a first step towards a climatological assessment of direct aerosol radiative forcing in the region under study.

  13. EVALUATION OF ACOUSTIC FORCES ON A PARTICLE IN AEROSOL MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Richard Dimenna, R

    2007-09-27

    The acoustic force exerted on a solid particle was evaluated to develop a fundamental understanding of the critical physical parameters or constraints affecting particle motion and capture in a collecting device. The application of an acoustic force to the collection of a range of submicron-to-micron particles in a highly turbulent airflow stream laden with solid particles was evaluated in the presence of other assisting and competing forces. This scoping estimate was based on the primary acoustic force acting directly on particles in a dilute aerosol system, neglecting secondary interparticle effects such as agglomeration of the sub-micron particles. A simplified analysis assuming a stable acoustic equilibrium with an infinite sound speed in the solid shows that for a solid-laden air flow in the presence of a standing wave, particles will move toward the nearest node. The results also show that the turbulent drag force on a 1-{micro}m particle resulting from eddy motion is dominant when compared with the electrostatic force or the ultrasonic acoustic force. At least 180 dB acoustic pressure level at 1 MHz is required for the acoustic force to be comparable to the electrostatic or turbulent drag forces in a high-speed air stream. It is noted that particle size and pressure amplitude are dominant parameters for the acoustic force. When acoustic pressure level becomes very large, the acoustic energy will heat up the surrounding air medium, which may cause air to expand. With an acoustic power of about 600 watts applied to a 2000-lpm air flow, the air temperature can increase by as much as 15 C at the exit of the collector.

  14. Characterization of Atmospheric Aerosol Particles from a Mining City in Southwest China Using Electron Probe microanalysis

    Science.gov (United States)

    Cheng, X.; Huang, Y.; Lu, H., III; Liu, Z., IV; Wang, N. V.

    2015-12-01

    Xin Cheng1, Yi Huang1*, Huilin Lu2, Zaidong Liu2, Ningming Wang21 Key Laboratory of Geological Nuclear Technology of Sichuan Province, College of Earth Science, Chengdu University of Technology, Chengdu 610059, China. ; E-mail:chengxin_cdut@163.com 2 College of Earth Science, Chengdu University of Technology, Chengdu 610059, China. ; *Corresponding author: E-mail: huangyi@cdut.cn Panzhihua is a mining city located at Pan-Xi Rift valley, southwest China. It has a long industrial history of vanadium-titanium magnetite mining, iron and steel smelting, and coal-fired power plants. Atomospheric environment has been seriously contaminated with airborne paticles, which is threatening human health.The harmful effects of aerosols are dependent on certain characteristics such as microphysical properties. However, few studsies have been carried out on morphological information contained on single atmospheric particles in this area. In this study, we provide a detailed morphologically and chemically characterization of airborne particles collected at Panzhihua city in October, 2014, using a quantitative single particle analysis based on EPXMA. The results indicate that based on their chemical composition, five major types of particles were identified. Among these, aluminosilicate particles have typical spherical shapes and are produced during the high-temperature combustion; Fe-containing particles contains high level of Mn, and more likely originated from mineralogical and steel industry; Si-containing particles can originate from mineralogical source; V-Ti-Mn-containing particles are also produced by steel industry; Ca-containing particles,these particles are CaCO3, mainly from the mining of limestone mine. The results help us on tracing and partitioning different sources of atomospheric particles in the industrial area. Fig.1 Fe-rich shperical particles

  15. Aerosol arriving on the Caribbean island of Barbados: physical properties and origin

    Science.gov (United States)

    Wex, Heike; Dieckmann, Katrin; Roberts, Greg C.; Conrath, Thomas; Izaguirre, Miguel A.; Hartmann, Susan; Herenz, Paul; Schäfer, Michael; Ditas, Florian; Schmeissner, Tina; Henning, Silvia; Wehner, Birgit; Siebert, Holger; Stratmann, Frank

    2016-11-01

    The marine aerosol arriving at Barbados (Ragged Point) was characterized during two 3-week long measurement periods in November 2010 and April 2011, in the context of the measurement campaign CARRIBA (Cloud, Aerosol, Radiation and tuRbulence in the trade wInd regime over BArbados). Through a comparison between ground-based and airborne measurements it was shown that the former are representative of the marine boundary layer at least up to cloud base. In general, total particle number concentrations (Ntotal) ranged from as low as 100 up to 800 cm-3, while number concentrations for cloud condensation nuclei (NCCN) at a supersaturation of 0.26 % ranged from some 10 to 600 cm-3. Ntotal and NCCN depended on the air mass origin. Three distinct types of air masses were found. One type showed elevated values for both Ntotal and NCCN and could be attributed to long-range transport from Africa, by which biomass burning particles from the Sahel region and/or mineral dust particles from the Sahara were advected. The second and third type both had values for NCCN below 200 cm-3 and a clear minimum in the particle number size distribution (NSD) around 70 to 80 nm (Hoppel minimum). While for one of these two types the accumulation mode was dominating (albeit less so than for air masses advected from Africa), the Aitken mode dominated the other and contributed more than 50 % of all particles. These Aitken mode particles likely were formed by new particle formation no more than 3 days prior to the measurements. Hygroscopicity of particles in the CCN size range was determined from CCN measurements to be κ = 0.66 on average, which suggests that these particles contain mainly sulfate and do not show a strong influence from organic material, which might generally be the case for the months during which measurements were made. The average κ could be used to derive NCCN from measured number size distributions, showing that this is a valid approach to obtain NCCN. Although the total

  16. Use of stable carbon and nitrogen isotope ratios in size segregated aerosol particles for the O/I penetration evaluation

    Science.gov (United States)

    Garbaras, Andrius; Garbariene, Inga; Masalaite, Agne; Ceburnis, Darius; Krugly, Edvinas; Kvietkus, Kestutis; Remeikis, Vidmantas; Martuzevicius, Dainius

    2015-04-01

    particles penetrates from outside to inside. Observed isotope ratio depletion indicates that information about aerosol sources can be lost if measurements are performed only inside house. Using carbon and nitrogen isotope ratios data set, we were able to identify and distinguish main aerosol sources (traffic, heating activities) and penetration of aerosol particles from outdoor to indoor. Acknowledgment This work was supported by Research Council of Lithuania under grant "Pollution Control in Biomass Combustion: from Pollutant Formation to Human Exposure" (BioMassPoll), Project no. ATE05/2012. EPA Ireland is acknowledged for the fellowship grant of D. Ceburnis 1. Garbaras, A. Masalaite, I. Garbariene, D. Ceburnis, E. Krugly V. Remeikis, E. Puida K. Kvietkus, D. Martuzevicius, Stable carbon fractionation in size-segregated aerosol particles produced by controlled biomass burning, Journal of Aerosol Science, Vol. 79, p. 86-96 (2015); 2. D. Ceburnis, A. Garbaras, S. Szidat, M. Rinaldi, S. Fahrni, N. Perron, L. Wacker, S. Leinert, V. Remeikis, M. C. Facchini, A. S. H. Prevot, S. G. Jennings, and C. D. O'Dowd, Quantification of the carbonaceous matter origin in submicron marine aerosol particles by dual carbon isotope analysis, Atmospheric Chemistry and Physics, Vol 11, pp. 8593-8606 (2011); 3. V. Ulevicius, S. Bycenkiene, V. Remeikis, A. Garbaras, S. Kecorius, J. Andriejauskiene, D. Jasineviciene, G. Mocnik, Characterization of pollution events in the East Baltic region affected by regional biomass fire emissions, Atmospheric Research, Vol. 98 (2-4), pp. 190-200 (2010).

  17. Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Wachsmuth

    2002-01-01

    Full Text Available Uptake of HOBr on sea salt aerosol, sea salt brine or ice is believed to be a key process providing a source of photolabile bromine (Br2 and sustaining ozone depletion cycles in the Arctic troposphere. In the present study, uptake of HOBr on sodium bromide (NaBr aerosol particles was investigated at an extremely low HOBr concentration of 300 cm-3 using the short-lived radioactive isotopes 83-86Br. Under these conditions, at maximum one HOBr molecule was taken up per particle. The rate of uptake was clearly limited by the mass accommodation coefficient, which was calculated to be 0.6 ± 0.2. This value is a factor of 10 larger than estimates used in earlier models. The atmospheric implications are discussed using the box model "MOCCA'', showing that the increase of the accommodation coefficient of HOBr by a factor of 10 only slightly affects net ozone loss, but significantly increases chlorine release.

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

    Science.gov (United States)

    Ro, C.

    2008-12-01

    An electron probe X-ray microanalysis (EPMA) technique using an energy-dispersive X-ray detector with an ultra-thin window, named low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements such as C, N, and O, as well as higher-Z elements that can be analyzed by conventional energy-dispersive EPMA (ED-EPMA). The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual environmental particles has improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally important atmospheric particles, e.g. sulfates, nitrates, ammonium, and carbonaceous particles, contain low-Z elements. In addition, an expert system that can perform chemical speciation from the elemental composition data obtained by the low-Z particle EPMA has been developed. The low-Z particle EPMA was applied to characterize K-feldspar particle samples of which the chemical compositions are well defined by the use of various bulk analytical methods. Chemical compositions of the K-feldspar samples obtained from the low-Z particle EPMA turn out to be very close to those from bulk analyses. The low-Z particle EPMA technique has been applied for the characterization of atmospheric aerosol particle samples, including Asian dust, urban, and indoor particulate samples: (1) The extent of chemical modification of Asian dust particles sampled in Chuncheon and Incheon, Korea, during several Asian dust storm events occurred in 2002-2006 was investigated. Mixing of Asian dust with air pollutants and sea-salts strongly depends on the characteristics of Asian dust storm events such as air-mass backward trajectories. For instance, no significant chemical modification of mineral dust corresponded to fast moving air-masses at high altitudes. Inversely, extensive chemical modification was

  19. Biological aerosol particle concentrations and size distributions measured in pristine tropical rainforest air during AMAZE-08

    Science.gov (United States)

    Huffman, J. A.; Sinha, B.; Garland, R. M.; Snee-Pollmann, A.; Gunthe, S. S.; Artaxo, P.; Martin, S. T.; Andreae, M. O.; Pöschl, U.

    2012-09-01

    As a part of the AMAZE-08 campaign during the wet season in the rainforest of Central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m-3 (4.0-13.2 × 104 m-3) and 0.72 μg m-3 (0.42-1.19 μg mm-3), respectively, accounting for 24% (11-41%) of total particle number and 47% (25-65%) of total particle mass. During the five-week campaign in February-March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM), light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP) mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no fungal staining. This mode consisted of single bacterial cells, brochosomes and various fragments of biological material. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF) techniques provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles. We also show that primary biological particles, fungal spores in particular, are key fractions of supermicron aerosol in the Amazon and that, especially when coated by mixed inorganic

  20. Biological aerosol particle concentrations and size distributions measured in pristine tropical rainforest air during AMAZE-08

    Directory of Open Access Journals (Sweden)

    J. A. Huffman

    2012-09-01

    Full Text Available As a part of the AMAZE-08 campaign during the wet season in the rainforest of Central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS was operated for continuous measurements of fluorescent biological aerosol particles (FBAP. In the coarse particle size range (> 1 μm the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m−3 and 0.72 μg m−3 (0.42–1.19 μg mm−3, respectively, accounting for 24% (11–41% of total particle number and 47% (25–65% of total particle mass. During the five-week campaign in February–March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM, light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no fungal staining. This mode consisted of single bacterial cells, brochosomes and various fragments of biological material. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF techniques provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles. We also show that primary biological particles, fungal spores in particular, are key

  1. Deliquescence and Efflorescence Processes of Aerosol Particles Studied by in situ FTIR and Raman Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Li-jun Zhao; Feng Wang; Kun Zhang; Qing-xuan Zeng; Yun-hong Zhang

    2008-01-01

    Deliquescence and efflorescence are the two most important physicochemical processes of aerosol particles.In deliquescence and efflorescence cycles of aerosol particles,many fundamental problems need to be investigated in detail on the molecular level,including ion and molecule interactions in supersaturated aerosols,metastable solid phases that may be formed,and microscopic structures and deliquescence mechanisms of aerosol particles.This paper presents a summary of the progress made in recent investigations of deliquescence and efflorescence processes of aerosol particles by four common spectral techniques,which are known as Raman/electrodynamic balance,Fourier transform infrared/aerosol flow tube,Fourier transform infrared/attenuated total reflection,and confocal Raman on a quartz substrate.

  2. Aerosol particles in the Mexican East Pacific Part I: processing and vertical redistribution by clouds

    Directory of Open Access Journals (Sweden)

    D. Baumgardner

    2005-01-01

    Full Text Available Airborne measurements of aerosol particle size distributions were made in the Mexican Intertropical Convergence Zone. The volume concentrations of submicron and super micron particles at cloud base were compared with those in near-cloud regions over a range of altitudes. Of 78 near-cloud regions analyzed, 68% and 45% had enhanced volumes of submicron particles and supermicron particles, respectively. In addition, 35% of these regions had supermicron particles removed, presumably by precipitation. In 61% of the cases the enhancement in volume occurred over the size range from 0.1 to 50 μm whereas only submicron volumes were enhanced in 35% of the cases. In regions near clouds that were formed in air of maritime origin the frequency of volume enhancement decreased with increasing altitude and was twice as frequent on the dissipating side of clouds compared to the growing side. No such differences were found in the regions near clouds formed in air originating from the land. The frequency and average magnitude of volume enhancement are in qualitative and quantitative agreement with previous observational and theoretical studies that relate enhancements in particle mass to the uptake by cloud droplets of SO2 accompanied by additional growth by droplet coalescence.

  3. Chemical composition and sources of coastal marine aerosol particles during the 2008 VOCALS-REx campaign

    Directory of Open Access Journals (Sweden)

    Y.-N. Lee

    2013-10-01

    Full Text Available The chemical composition of aerosol particles (Dp ≤ 1.5 μm was measured over the southeast Pacific ocean during the VOCALS-REx experiment between 16~October and 15 November 2008 using the US DOE G-1 aircraft. The objective of these flights was to gain an understanding of the sources and evolution of these aerosols, and how they interacted with the marine stratus cloud layer that prevails in this region of the globe. Our measurements showed that the marine boundary layer (MBL aerosol mass was dominated by non-sea-salt SO42−, followed by Na+, Cl−, Org, NH4+, and NO3−, in decreasing order of importance; CH3SO3−1 (MSA, Ca2+, and K+ rarely exceeded their limits of detection of ~0.05 and ~0.15 μg m−3 for anions and cations, respectively. The aerosols were strongly acidic as the NH4+ to SO42− equivalence ratio was typically − deficits caused by both HNO3 and H2SO4, and were externally mixed with SO42− particles as the AMS detected no NO3− whilst uptake of HNO3 occurred only on SSA particles. The SSA loading as a function of wind speed agreed with that calculated from published relationships, and contributed only a small fraction of the total accumulation mode particle number. Vertical distribution of MBL SSA particles (Dp ≤ ~1.5 μm was uniform, suggesting a very limited dilution from entrainment of free tropospheric (FT air. It was inferred that because all of the aerosol species (except SSA exhibited a strong land-to-sea gradient, they were of continental origin. Comparison of relative changes in median values using LOWESS fits as proxies suggests that (1 an oceanic source of NH3 is present between 72° W and 76° W, and (2 additional organic aerosols from biomass burns or biogenic precursors were emitted from coastal regions south of 31° S, with possible cloud processing, and (3 FT contributions to MBL gas and aerosols were negligible. Positive Matrix Factorization analysis of organic aerosol mass spectra obtained with

  4. Mass spectrometric analysis and aerodynamic properties of various types of combustion-related aerosol particles

    Science.gov (United States)

    Schneider, J.; Weimer, S.; Drewnick, F.; Borrmann, S.; Helas, G.; Gwaze, P.; Schmid, O.; Andreae, M. O.; Kirchner, U.

    2006-12-01

    Various types of combustion-related particles in the size range between 100 and 850 nm were analyzed with an aerosol mass spectrometer and a differential mobility analyzer. The measurements were performed with particles originating from biomass burning, diesel engine exhaust, laboratory combustion of diesel fuel and gasoline, as well as from spark soot generation. Physical and morphological parameters like fractal dimension, effective density, bulk density and dynamic shape factor were derived or at least approximated from the measurements of electrical mobility diameter and vacuum aerodynamic diameter. The relative intensities of the mass peaks in the mass spectra obtained from particles generated by a commercial diesel passenger car, by diesel combustion in a laboratory burner, and by evaporating and re-condensing lubrication oil were found to be very similar. The mass spectra from biomass burning particles show signatures identified as organic compounds like levoglucosan but also others which are yet unidentified. The aerodynamic behavior yielded a fractal dimension (Df) of 2.09 +/- 0.06 for biomass burning particles from the combustion of dry beech sticks, but showed values around three, and hence more compact particle morphologies, for particles from combustion of more natural oak. Scanning electron microscope images confirmed the finding that the beech combustion particles were fractal-like aggregates, while the oak combustion particles displayed a much more compact shape. For particles from laboratory combusted diesel fuel, a Df value of 2.35 was found, for spark soot particles, Df [approximate] 2.10. The aerodynamic properties of fractal-like particles from dry beech wood combustion indicate an aerodynamic shape factor [chi] that increases with electrical mobility diameter, and a bulk density of 1.92 g cm-3. An upper limit of [chi] [approximate] 1.2 was inferred for the shape factor of the more compact particles from oak combustion.

  5. Fast determination of the relative elemental and organic carbon content of aerosol samples by on-line single-particle aerosol time-of-flight mass spectrometry.

    Science.gov (United States)

    Ferge, T; Karg, E; Schröppel, A; Coffee, K R; Tobias, H J; Frank, M; Gard, E E; Zimmermann, R

    2006-05-15

    Different particulate matter (PM) samples were investigated by on-line single-particle aerosol time-of-flight mass spectrometry (ATOFMS). The samples consist of soot particulates made by a diffusion flame soot generator (combustion aerosol standard, CAST), industrially produced soot material (printex), soot from a diesel passenger car as well as ambient particulates (urban dust (NIST) and road tunnel dust). Five different CAST soot particle samples were generated with different elemental carbon (EC) and organic carbon (OC) content. The samples were reaerosolized and on-line analyzed by ATOFMS, as well as precipitated on quartz filters for conventional EC/OC analysis. For each sample ca. 1000 ATOFMS single-particle mass spectra were recorded and averaged. A typical averaged soot ATOFMS mass spectrum shows characteristic carbon cluster peak progressions (Cn+) as well as hydrogen-poor carbon cluster peaks (CnH(1-3)+). These peaks are originated predominately from the elemental carbon (EC) content of the particles. Often additional peaks, which are not due to carbon clusters, are observed, which either are originated from organic compounds (OC-organic carbon), or from the non-carbonaceous inorganic content of the particles. By classification of the mass spectral peaks as elemental carbon (i.e., the carbon cluster progression peaks) or as peaks originated from organic compounds (i.e., molecular and fragment ions), the relative abundance of elemental (EC) and organic carbon (OC) can be determined. The dimensionless TC/EC values, i.e., the ratio of total carbon content (TC, TC = OC + EC) to elemental carbon (EC), were derived from the ATOFMS single-particle aerosol mass spectrometry data. The EC/TC values measured by ATOFMS were compared with the TC/EC values determined by the thermal standard techniques (thermooptical and thermocoulometric method). A good agreement between the EC/TC values obtained by on-line ATOFMS and the offline standard method was found.

  6. Investigate the relationship between multiwavelength lidar ratios and aerosol size distributions using aerodynamic particle sizer spectrometer

    Science.gov (United States)

    Zhao, Hu; Hua, Dengxin; Mao, Jiandong; Zhou, Chunyan

    2017-02-01

    The real aerosol size distributions were obtained by aerodynamic particle sizer spectrometer (APS) in China YinChuan. The lidar ratios at wavelengths of 355 nm, 532 nm and 1064 nm were calculated using Mie theory. The effective radius of aerosol particles reff and volume C/F ratio (coarse/fine) Vc/f were retrieved from the real aerosol size distributions. The relationship between multiwavelength lidar ratios and particle reff and Vc/f were investigated. The results indicate that the lidar ratio is positive correlated to the particle reff and Vc/f. The lidar ratio is more sensitive to the coarse particles. The short wavelength lidar ratio is more sensitive to the particle Vc/f and the long wavelength lidar ratio is more sensitive to the particle reff. The wavelength dependency indicated that the lidar ratios decrease with increasing the wavelength. The lidar ratios are almost irrelevant to the shape and total particles of aerosol size distributions.

  7. Aerosol particle properties in a South American megacity

    Science.gov (United States)

    Ulke, Ana; Torres-Brizuela, Marcela; Raga, Graciela; Baumgardner, Darrel; Cancelada, Marcela

    2015-04-01

    The subtropical city of Buenos Aires is located on the western shore of Río de la Plata, on the southeastern coast of Argentina. It is the second largest metropolitan area in South America, with a population density of around 14 thousand people per km2. When all 24 counties of the Great Buenos Aires Metropolitan Area are included it is the third-largest conurbation in Latin America, with a population of around fifteen million inhabitants. The generalized worldwide trend to concentrate human activities in urban regions that continue to expand in area, threatens the local and regional environment. Air pollution in the Buenos Aires airshed is due to local sources (mainly the mobile sources, followed by the electric power plants and some industries) and to distant sources (like biomass burning, dust, marine aerosols and occasionally volcanic ash) whose products arrive in the city area due to the regional transport patterns. Previous research suggests that ambient aerosol particle concentrations should be considered an air quality problem. A field campaign was conducted in Buenos Aires in 2011 in order to characterize some aerosol particles properties measured for the first time in the city. Measurements began in mid- April and continued until December. The field observations were done in a collaborative effort between the Universities of Mexico (UNAM) and Buenos Aires (UBA). A suite of instruments was installed on the roof of an UBA laboratory and classroom buildings (34.54° S, 58.44° W) at an altitude of approximately 30 m above sea level. The measurements included the number concentration of condensation nuclei (CN) larger than approximately 50 nm, the mass concentration of particle-bound polycyclic aromatic hydrocarbons (PPAH), the scattering (Bscat) and absorption (Babs) coefficients at 550 nm and the vertical profiles of backscattered light from aerosols at a wavelength of 910 nm using a ceilometer. In addition, a weather station recorded the meteorological

  8. Review: engineering particles using the aerosol-through-plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia C [UNM; Richard, Monique [TEMA

    2009-01-01

    For decades, plasma processing of materials on the nanoscale has been an underlying enabling technology for many 'planar' technologies, particularly virtually every aspect of modern electronics from integrated-circuit fabrication with nanoscale elements to the newest generation of photovoltaics. However, it is only recent developments that suggest that plasma processing can be used to make 'particulate' structures of value in fields, including catalysis, drug delivery, imaging, higher energy density batteries, and other forms of energy storage. In this paper, the development of the science and technology of one class of plasma production of particulates, namely, aerosol-through-plasma (A-T-P), is reviewed. Various plasma systems, particularly RF and microwave, have been used to create nanoparticles of metals and ceramics, as well as supported metal catalysts. Gradually, the complexity of the nanoparticles, and concomitantly their potential value, has increased. First, unique two-layer particles were generated. These were postprocessed to create unique three-layer nanoscale particles. Also, the technique has been successfully employed to make other high-value materials, including carbon nanotubes, unsupported graphene, and spherical boron nitride. Some interesting plasma science has also emerged from efforts to characterize and map aerosol-containing plasmas. For example, it is clear that even a very low concentration of particles dramatically changes plasma characteristics. Some have also argued that the local-thermodynamic-equilibrium approach is inappropriate to these systems. Instead, it has been suggested that charged- and neutral-species models must be independently developed and allowed to 'interact' only in generation terms.

  9. Ozone oxidation of sulfur in sea-salt aerosol particles during the Azores Marine Aerosol and Gas Exchange experiment

    Science.gov (United States)

    Sievering, H.; Gorman, E.; Ley, T.; Pszenny, A.; Springer-Young, M.; Boatman, J.; Kim, Y.; Nagamoto, C.; Wellman, D.

    1995-11-01

    Sea-salt aerosol particles in the lowest tens of meters above the ocean are, typically, more than three-fourths water on a volume basis. Calculations herein indicate that aqueous-phase conversion of sulfur dioxide dissolved in the water associated with sea-salt particles (sea-salt aerosol water) supported the production of 2-8 nmol m-3 of nonsea-salt sulfate (nssSO4=) during the Marine Aerosol and Gas Exchange (MAGE) experiment intensives. This production is based on ozone oxidation of dissolved SO2 in sea-salt aerosol water and accounts for sulfur gas and ozone mass transfer limitations as a function of sea-salt particle size. Measurements showed that 1-15 nmol m-3 of nssSO4= was actually present in the sea-salt particle mode except for four enhanced concentration cases due to continental sulfur input. The range in predicted, as well as observed, nssSO4= was primarily due to variability in sea-salt aerosol water volume. The nssSO4= produced by ozone oxidation of sulfur dioxide, being in the sea-salt particle mode with observed volume geometric median diameter of 3.5-5 μm, is dry deposited at a fairly rapid rate. The remainder, being large-particle cloud condensation nuclei, may contribute little to cloud albedo over the global oceans. The two papers following this one, Kim et al. (this issue) on aerosol size distribution and water content and Parfai et al. (this issue) on compositional variations of sea-salt-mode aerosol particles observed by electron microscopy, complement and support results presented here. All three present results of the MAGE experiment and precede a forthcoming special issue of the Journal of Geophysical Research-Atmospheres on MAGE (B. Huebert, guest editor).

  10. Deposition flux of aerosol particles and 15 polycyclic aromatic hydrocarbons in the North China Plain.

    Science.gov (United States)

    Wang, Xilong; Liu, Shuzhen; Zhao, Jingyu; Zuo, Qian; Liu, Wenxin; Li, Bengang; Tao, Shu

    2014-04-01

    The present study examined deposition fluxes of aerosol particles and 15 polycyclic aromatic hydrocarbons (PAHs) associated with the particles in the North China Plain. The annual mean deposition fluxes of aerosol particles and 15 PAHs were 0.69 ± 0.46 g/(m(2) ×d) and 8.5 ± 6.2 μg/(m(2) ×d), respectively. Phenanthrene, fluoranthene, pyrene, chrysene, benzo[b]fluoranthene, and benzo[k]fluoranthene were the dominant PAHs bound to deposited aerosol particles throughout the year. The total concentration of 15 PAHs in the deposited aerosol particles was the highest in winter but lowest in spring. The highest PAH concentration in the deposited aerosol particles in winter was because the heating processes highly increased the concentration in atmospheric aerosol particles. Low temperature and weak sunshine in winter reduced the degradation rate of deposited aerosol particle-bound PAHs, especially for those with low molecular weight. The lowest PAH concentration in deposited aerosol particles in spring resulted from the frequently occurring dust storms, which diluted PAH concentrations. The mean deposition flux of PAHs with aerosol particles in winter (16 μg/[m(2) ×d]) reached 3 times to 5 times that in other seasons (3.5-5.0 μg/[m(2) ×d]). The spatial variation of the deposition flux of PAHs with high molecular weight (e.g., benzo[a]pyrene) was consistent with their concentrations in the atmospheric aerosol particles, whereas such a phenomenon was not observed for those with low molecular weight (e.g., phenanthrene) because of their distinct hydrophobicity, Henry's law constant, and the spatially heterogeneous meteorological conditions.

  11. Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

    Energy Technology Data Exchange (ETDEWEB)

    Keskinen, J.; Hautanen, J.; Laitinen, A. [Tampere Univ. of Technology (Finland). Physics

    1997-10-01

    The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

  12. Chemical composition of ambient aerosol, ice residues and cloud droplet residues in mixed-phase clouds: single particle analysis during the Cloud and Aerosol Characterization Experiment (CLACE 6

    Directory of Open Access Journals (Sweden)

    M. Kamphus

    2009-07-01

    Full Text Available Two different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l. during the Cloud and Aerosol Characterization Experiment (CLACE 6 in February and March 2007. During mixed phase cloud events ice crystals from 5 μm up to 20 μm were separated from large ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI. During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR were analyzed for size and composition by two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT and a commercial Aerosol Time of Flight Mass Spectrometer (ATOFMS, TSI Model 3800. During CLACE 6 the SPLAT instrument characterized 355 individual ice residues that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 particles. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094. The measurements showed that mineral dust particles were strongly enhanced in the ice particle residues. 57% of the SPLAT spectra from ice residues were dominated by signatures from mineral compounds, and 78% of the ATOFMS spectra. Sulfate and nitrate containing particles were strongly

  13. 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.

  14. Hygroscopic growth of atmospheric aerosol particles and its relation to nucleation scavenging in clouds

    Energy Technology Data Exchange (ETDEWEB)

    Svenningsson, B.

    1997-11-01

    Aerosol particles in the atmosphere are important in several aspects. Some major aerosol constituents that are deposited in ecosystems are acidic or fertilizers and some minor or trace constituents are toxic. Aerosol particles are also involved in the earth`s radiation balance, both directly by scattering the sunlight and indirectly by influencing the clouds. All these effects are influenced by the interaction between the aerosol particles and water vapour. A tandem differential mobility analyser (TDMA) has been designed to measure hygroscopic growth, i.e. the particle diameter change due to uptake of water at well defined relative humidities below 100%. Tests of the instrument performance have been made using aerosol particles of pure inorganic salts. Three field experiments have been performed as parts of large fog and cloud experiments. Bimodal hygroscopic growth spectra were found: less-hygroscopic particles containing a few percent and more-hygroscopic particles around 50% by volume of hygroscopically active material. In general the fraction of less-hygroscopic particles decreases with particle size and it is larger in polluted continental aerosols than in remote background aerosols. This external mixing cannot be fully understood using present views on the formation of aerosols. Evidence or the importance of the external mixing on the cloud nucleating properties of the particles are found in comparisons between hygroscopic growth spectra for the total aerosol, the interstitial aerosol in clouds, and cloud drop residuals. Cloud condensation nuclei spectra, calculated using aerosol particle size distributions and hygroscopic growth spectra, in combination with information on the major inorganic ions are presented. These CCN spectra reveal for instance that the influence of less-hygroscopic particles on the cloud droplets increases with increasing peak supersaturation. The fraction of the particles that were scavenged to cloud drops, as a function of particle

  15. The characterization of atmospheric aerosols: Application to heterogeneous gas-particle reactions

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.M.; Henson, B.F.; Wilson, K.R. [Los Alamos National Lab., NM (United States); Prather, K.A.; Noble, C.A. [Univ. of California, Riverside, CA (United States)

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project of the Los Alamos National Laboratory (LANL). The objective of this collaborative research project is the measurement and modeling of atmospheric aerosols and heterogeneous (gas/aerosol) chemical reactions. The two major accomplishments are single particle characterization of tropospheric particles and experimental investigation of simulated stratospheric particles and reactions thereon. Using aerosol time-of-flight mass spectrometry, real-time and composition measurements of single particles are performed on ambient aerosol samples. This technique allows particle size distributions for chemically distinct particle types to be described. The thermodynamics and chemical reactivity of polar stratospheric clouds are examined using vapor deposited thin ice films. Employing nonlinear optical methods, as well as other techniques, phase transitions on both water and acid ices are monitored as a function of temperature or the addition of gases.

  16. Chamber bioaerosol study: human emissions of size-resolved fluorescent biological aerosol particles.

    Science.gov (United States)

    Bhangar, S; Adams, R I; Pasut, W; Huffman, J A; Arens, E A; Taylor, J W; Bruns, T D; Nazaroff, W W

    2016-04-01

    Humans are a prominent source of airborne biological particles in occupied indoor spaces, but few studies have quantified human bioaerosol emissions. The chamber investigation reported here employs a fluorescence-based technique to evaluate bioaerosols with high temporal and particle size resolution. In a 75-m(3) chamber, occupant emission rates of coarse (2.5-10 μm) fluorescent biological aerosol particles (FBAPs) under seated, simulated office-work conditions averaged 0.9 ± 0.3 million particles per person-h. Walking was associated with a 5-6× increase in the emission rate. During both walking and sitting, 60-70% or more of emissions originated from the floor. The increase in emissions during walking (vs. while sitting) was mainly attributable to release of particles from the floor; the associated increased vigor of upper body movements also contributed. Clothing, or its frictional interaction with human skin, was demonstrated to be a source of coarse particles, and especially of the highly fluorescent fraction. Emission rates of FBAPs previously reported for lecture classes were well bounded by the experimental results obtained in this chamber study. In both settings, the size distribution of occupant FBAP emissions had a dominant mode in the 3-5 μm diameter range.

  17. Seasonal variations in aerosol particle composition at the puy-de-Dôme research station in France

    Directory of Open Access Journals (Sweden)

    E. J. Freney

    2011-12-01

    Full Text Available Detailed investigations of the chemical and microphysical properties of atmospheric aerosol particles were performed at the puy-de-Dôme (pdD research station (1465 m in autumn (September and October 2008, winter (February and March 2009, and summer (June 2010 using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS. Over the three campaigns, the average mass concentrations of the non-refractory submicron particles ranged from 10 μg m−3 up to 27 μg m−3. Highest nitrate and ammonium mass concentrations were measured during the winter and during periods when marine modified airmasses were arriving at the site, whereas highest concentrations of organic particles were measured during the summer and during periods when continental airmasses arrived at the site. The measurements reported in this paper show that atmospheric particle composition is strongly influenced by both the season and the origin of the airmass. The total organic mass spectra were analysed using positive matrix factorisation to separate individual organic components contributing to the overall organic particle mass concentrations. These organic components include a low volatility oxygenated organic aerosol particle (LV-OOA and a semi-volatile organic aerosol particle (SV-OOA. Correlations of the LV-OOA components with fragments of m/z 60 and m/z 73 (mass spectral markers of wood burning during the winter campaign suggest that wintertime LV-OOA are related to aged biomass burning emissions, whereas organic aerosol particles measured during the summer are likely linked to biogenic sources. Equivalent potential temperature calculations, gas-phase, and LIDAR measurements define whether the research site is in the planetary boundary layer (PBL or in the free troposphere (FT/residual layer (RL. We observe that SV-OOA and nitrate particles are associated with air masses arriving from the PBL where as particle composition measured from RL

  18. Method and device for detecting and identifying bio-aerosol particles in the air

    NARCIS (Netherlands)

    Stowers. M.A.; Wuijckhuijse, A.L.; Marijnissen, J.C.; Kientz, C.E.

    2002-01-01

    In a method for detecting and identifying bioaerosol particles in the air, the bioaerosol particles in a particle stream are selected in an ATOFMS (aerosol time-of-flight mass spectrometer) by means of fluorescence techniques, and only the selected bioaerosol particles are ionized, for instance on t

  19. On the composition of ammonia–sulfuric-acid ion clusters during aerosol particle formation

    OpenAIRE

    S. Schobesberger; Franchin, A.; Bianchi, F.(University of Turin, Turin, I-10125, Italy); L. Rondo; Duplissy, J.; Kürten, A.; Ortega, I. K.; Metzger, A.; R. Schnitzhofer; Almeida, J; Amorim, A.; Dommen, J.; Dunne, E.M.; Ehn, M.; S. Gagné

    2015-01-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments were conducted in th...

  20. On the composition of ammonia-sulfuric acid clusters during aerosol particle formation

    OpenAIRE

    S. Schobesberger; Franchin, A.; Bianchi, F.(University of Turin, Turin, I-10125, Italy); L. Rondo; Duplissy, J.; Kürten, A.; Ortega, I. K.; Metzger, A.; R. Schnitzhofer; Almeida, J; Amorim, A.; Dommen, J.; Dunne, E.M.; Ehn, M.; S. Gagné

    2014-01-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments wer...

  1. Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions

    Science.gov (United States)

    Mason, R. H.; Si, M.; Li, J.; Chou, C.; Dickie, R.; Toom-Sauntry, D.; Pöhlker, C.; Yakobi-Hancock, J. D.; Ladino, L. A.; Jones, K.; Leaitch, W. R.; Schiller, C. L.; Abbatt, J. P. D.; Huffman, J. A.; Bertram, A. K.

    2015-11-01

    Information on what aerosol particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which aerosol particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between -15 and -25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between -15 and -25 °C at this site for the time period studied. At -30 °C, INP number concentrations are also well correlated with number concentrations of the total aerosol particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving chemical tracers of marine aerosols and marine biological activity, sodium and methanesulfonic acid, indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated. This finding illustrates that additional measurements are needed to improve parameterizations of INPs and their

  2. Improved Tandem Measurement Techniques for Aerosol Particle Analysis

    Science.gov (United States)

    Rawat, Vivek Kumar

    Non-spherical, chemically inhomogeneous (complex) nanoparticles are encountered in a number of natural and engineered environments, including combustion systems (which produces highly non-spherical aggregates), reactors used in gas-phase materials synthesis of doped or multicomponent materials, and in ambient air. These nanoparticles are often highly diverse in size, composition and shape, and hence require determination of property distribution functions for accurate characterization. This thesis focuses on development of tandem mobility-mass measurement techniques coupled with appropriate data inversion routines to facilitate measurement of two dimensional size-mass distribution functions while correcting for the non-idealities of the instruments. Chapter 1 provides the detailed background and motivation for the studies performed in this thesis. In chapter 2, the development of an inversion routine is described which is employed to determine two dimensional size-mass distribution functions from Differential Mobility Analyzer-Aerosol Particle Mass analyzer tandem measurements. Chapter 3 demonstrates the application of the two dimensional distribution function to compute cumulative mass distribution function and also evaluates the validity of this technique by comparing the calculated total mass concentrations to measured values for a variety of aerosols. In Chapter 4, this tandem measurement technique with the inversion routine is employed to analyze colloidal suspensions. Chapter 5 focuses on application of a transverse modulation ion mobility spectrometer coupled with a mass spectrometer to study the effect of vapor dopants on the mobility shifts of sub 2 nm peptide ion clusters. These mobility shifts are then compared to models based on vapor uptake theories. Finally, in Chapter 6, a conclusion of all the studies performed in this thesis is provided and future avenues of research are discussed.

  3. Connecting Chemistry and Climate through Aerosol Particles : Laboratory and Field Studies of Cloud Condensation Nuclei /

    OpenAIRE

    Collins, Douglas Bradford

    2014-01-01

    The influence of aerosol particles on the Earth's climate is a major driver of scientific uncertainty in assessing future conditions. The importance of aerosols in their role as cloud condensation nuclei (CCN) and ice nuclei (IN), known as the Aerosol Indirect Effect, is most poorly understood. The number concentration of CCN available to nucleate droplets can have important influences on cloud albedo, lifetime, and propensity to form precipitation. Natural sources are of particular importanc...

  4. Method and device for detecting and identifying bio-aerosol particles in the air

    OpenAIRE

    Stowers. M.A.; van Wuijckhuijse, A.L.; Marijnissen, J.C.; Kientz, C. E.

    2002-01-01

    In a method for detecting and identifying bioaerosol particles in the air, the bioaerosol particles in a particle stream are selected in an ATOFMS (aerosol time-of-flight mass spectrometer) by means of fluorescence techniques, and only the selected bioaerosol particles are ionized, for instance on the basis of MALDI (matrix-assisted laser desorption/ionization), after which the resulting ions are detected and the bioaerosol particles are identified.; The selection of bioaerosol particles take...

  5. Electron mean free path from angle-dependent photoelectron spectroscopy of aerosol particles

    CERN Document Server

    Goldmann, Maximilian; West, Adam H C; Yoder, Bruce L; Signorell, Ruth

    2015-01-01

    We propose angle-resolved photoelectron spectroscopy of aerosol particles as an alternative way to determine the electron mean free path of low energy electrons in solid and liquid materials. The mean free path is obtained from fits of simulated photoemission images to experimental ones over a broad range of different aerosol particle sizes. The principal advantage of the aerosol approach is twofold. Firstly, aerosol photoemission studies can be performed for many different materials, including liquids. Secondly, the size-dependent anisotropy of the photoelectrons can be exploited in addition to size-dependent changes in their kinetic energy. These finite size effects depend in different ways on the mean free path and thus provide more information on the mean free path than corresponding liquid jet, thin film, or bulk data. The present contribution is a proof of principle employing a simple model for the photoemission of electrons and preliminary experimental data for potassium chloride aerosol particles.

  6. Spectro-microscopy of Ambient Aerosol Particles: Observational Constraints on Mixing State Parameterization

    Science.gov (United States)

    OBrien, R. E.; Wang, B.; Laskin, A.; West, M.; Riemer, N. S.; Gilles, M. K.; Moffet, R.

    2014-12-01

    Individual aerosol particles are often mixtures of multiple components such as inorganic salts, soot or elemental carbon, and organic molecules. The amounts of the different components in each particle and the particle morphologies will impact the CCN activity and the radiative properties of the aerosol population. A recent parameterization of the mixing state developed by Nicole Riemer and Matthew West provides a clear transition between ambient measurements of aerosol components and particle mixing states employed in climate models. Single particle spectro-microscopy techniques including scanning transmission x-ray microscopy/near-edge x-ray absorption fine structure spectroscopy (STXM/NEXAFS) and computer controlled scanning electron microscopy/energy dispersive x-ray spectroscopy (CCSEM/EDX) are used to measure the composition of aerosol particles from the CARES campaign at both T0 and T1. Here, we present results from the application of the per particle composition to a parameterization of the mixing state and provide constraints on the mixing state of ambient aerosol particles. The two microscopy techniques yield complementary information on the mixing state of the aerosol populations; STXM/NEXAFS provides information on the mixing state of the organic fraction while CCSEM/EDX provides information on the inorganic fraction.

  7. A combined particle trap/HTDMA hygroscopicity study of mixed inorganic/organic aerosol particles

    Science.gov (United States)

    Zardini, A. A.; Sjogren, S.; Marcolli, C.; Krieger, U. K.; Gysel, M.; Weingartner, E.; Baltensperger, U.; Peter, T.

    2008-09-01

    Atmospheric aerosols are often mixtures of inorganic and organic material. Organics can represent a large fraction of the total aerosol mass and are comprised of water-soluble and insoluble compounds. Increasing attention was paid in the last decade to the capability of mixed inorganic/organic aerosol particles to take up water (hygroscopicity). We performed hygroscopicity measurements of internally mixed particles containing ammonium sulfate and carboxylic acids (citric, glutaric, adipic acid) in parallel with an electrodynamic balance (EDB) and a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds were chosen to represent three distinct physical states. During hygroscopicity cycles covering hydration and dehydration measured by the EDB and the HTDMA, pure citric acid remained always liquid, adipic acid remained always solid, while glutaric acid could be either. We show that the hygroscopicity of mixtures of the above compounds is well described by the Zdanovskii-Stokes-Robinson (ZSR) relationship as long as the two-component particle is completely liquid in the ammonium sulfate/glutaric acid system; deviations up to 10% in mass growth factor (corresponding to deviations up to 3.5% in size growth factor) are observed for the ammonium sulfate/citric acid 1:1 mixture at 80% RH. We observe even more significant discrepancies compared to what is expected from bulk thermodynamics when a solid component is present. We explain this in terms of a complex morphology resulting from the crystallization process leading to veins, pores, and grain boundaries which allow for water sorption in excess of bulk thermodynamic predictions caused by the inverse Kelvin effect on concave surfaces.

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

    Science.gov (United States)

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

    2009-04-01

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

  9. Soot Aerosol Particles as Cloud Condensation Nuclei: from Ice Nucleation Activity to Ice Crystal Morphology

    Science.gov (United States)

    Pirim, Claire; Ikhenazene, Raouf; Ortega, Isamel Kenneth; Carpentier, Yvain; Focsa, Cristian; Chazallon, Bertrand; Ouf, François-Xavier

    2016-04-01

    Emissions of solid-state particles (soot) from engine exhausts due to incomplete fuel combustion is considered to influence ice and liquid water cloud droplet activation [1]. The activity of these aerosols would originate from their ability to be important centers of ice-particle nucleation, as they would promote ice formation above water homogeneous freezing point. Soot particles are reported to be generally worse ice nuclei than mineral dust because they activate nucleation at higher ice-supersaturations for deposition nucleation and at lower temperatures for immersion freezing than ratios usually expected for homogeneous nucleation [2]. In fact, there are still numerous opened questions as to whether and how soot's physico-chemical properties (structure, morphology and chemical composition) can influence their nucleation ability. Therefore, systematic investigations of soot aerosol nucleation activity via one specific nucleation mode, here deposition nucleation, combined with thorough structural and compositional analyzes are needed in order to establish any association between the particles' activity and their physico-chemical properties. In addition, since the morphology of the ice crystals can influence their radiative properties [3], we investigated their morphology as they grow over both soot and pristine substrates at different temperatures and humidity ratios. In the present work, Combustion Aerosol STandart soot samples were produced from propane using various experimental conditions. Their nucleation activity was studied in deposition mode (from water vapor), and monitored using a temperature-controlled reactor in which the sample's relative humidity is precisely measured with a cryo-hygrometer. Formation of water/ice onto the particles is followed both optically and spectroscopically, using a microscope coupled to a Raman spectrometer. Vibrational signatures of hydroxyls (O-H) emerge when the particle becomes hydrated and are used to characterize ice

  10. The online chemical analysis of single particles using aerosol beams and time of flight mass spectroscopy

    NARCIS (Netherlands)

    Kievit, O.; Weiss, M.; Verheijen, P.J.T.; Marijnissen, J.C.M.; Scarlett, B.

    This paper describes an on-line instrument, capable of measuring the size and chemical composition of single aerosol particles. Possible applications include monitoring aerosol reactors and studying atmospheric chemistry. The main conclusion is that a working prototype has been built and tested. It

  11. [Factors influencing particle measurement of aerosols and their retention in the lung].

    Science.gov (United States)

    Le Bouffant, L

    1977-01-01

    The dimensional characteristics of the particles of an aerosol depend on the means used for producing them. Mechanical spray and ultrasonic dispersion give polydispersed particles. On the other hand, centrifugal atomization produces a monodispersed aerosol. Particle retention in the lung system depends on the particle diameter. In addition, retention varies according to the respiratory characteristics: it is minimal for about 15 inspirations per minute. Using iron-59 labeled particles, it was shown that the degree of retention varies considerably from one individual to the other and accessibility to the depths of the lungs is decreased under the effect of certain lesions. Bronchial retention appears to be increased in smokers.

  12. Estimating marine aerosol particle volume and number from Maritime Aerosol Network data

    Directory of Open Access Journals (Sweden)

    A. M. Sayer

    2012-09-01

    Full Text Available As well as spectral aerosol optical depth (AOD, aerosol composition and concentration (number, volume, or mass are of interest for a variety of applications. However, remote sensing of these quantities is more difficult than for AOD, as it is more sensitive to assumptions relating to aerosol composition. This study uses spectral AOD measured on Maritime Aerosol Network (MAN cruises, with the additional constraint of a microphysical model for unpolluted maritime aerosol based on analysis of Aerosol Robotic Network (AERONET inversions, to estimate these quantities over open ocean. When the MAN data are subset to those likely to be comprised of maritime aerosol, number and volume concentrations obtained are physically reasonable. Attempts to estimate surface concentration from columnar abundance, however, are shown to be limited by uncertainties in vertical distribution. Columnar AOD at 550 nm and aerosol number for unpolluted maritime cases are also compared with Moderate Resolution Imaging Spectroradiometer (MODIS data, for both the present Collection 5.1 and forthcoming Collection 6. MODIS provides a best-fitting retrieval solution, as well as the average for several different solutions, with different aerosol microphysical models. The "average solution" MODIS dataset agrees more closely with MAN than the "best solution" dataset. Terra tends to retrieve lower aerosol number than MAN, and Aqua higher, linked with differences in the aerosol models commonly chosen. Collection 6 AOD is likely to agree more closely with MAN over open ocean than Collection 5.1. In situations where spectral AOD is measured accurately, and aerosol microphysical properties are reasonably well-constrained, estimates of aerosol number and volume using MAN or similar data would provide for a greater variety of potential comparisons with aerosol properties derived from satellite or chemistry transport model data. However, without accurate AOD data and prior knowledge of

  13. Ambient measurement of fluorescent aerosol particles with a WIBS in the Yangtze River Delta of China: potential impacts of combustion-related aerosol particles

    Science.gov (United States)

    Yu, Xiawei; Wang, Zhibin; Zhang, Minghui; Kuhn, Uwe; Xie, Zhouqing; Cheng, Yafang; Pöschl, Ulrich; Su, Hang

    2016-09-01

    Fluorescence characteristics of aerosol particles in a polluted atmosphere were studied using a wideband integrated bioaerosol spectrometer (WIBS-4A) in Nanjing, Yangtze River Delta area of China. We observed strong diurnal and day-to-day variations of fluorescent aerosol particles (FAPs). The average number concentrations of FAPs (1-15 µm) detected in the three WIBS measurement channels (FL1: 0.6 cm-3, FL2: 3.4 cm-3, FL3: 2.1 cm-3) were much higher than those observed in forests and rural areas, suggesting that FAPs other than bioaerosols were detected. We found that the number fractions of FAPs were positively correlated with the black carbon mass fraction, especially for the FL1 channel, indicating a large contribution of combustion-related aerosols. To distinguish bioaerosols from combustion-related FAPs, we investigated two classification schemes for use with WIBS data. Our analysis suggests a strong size dependence for the fractional contributions of different types of FAPs. In the FL3 channel, combustion-related particles seem to dominate the 1-2 µm size range while bioaerosols dominate the 2-5 µm range. The number fractions of combustion-related particles and non-combustion-related particles to total aerosol particles were ˜ 11 and ˜ 5 %, respectively.

  14. The Formation of Porous Membranes by Filtration of Aerosol Nano-particles

    DEFF Research Database (Denmark)

    Andersen, Sune Klint; Johannessen, Tue; Mosleh, Majid

    2002-01-01

    Flame-generated aerosol particles of Al2O3 were deposited by gas filtration on two types of porous and ceramic tubes of α-Al2O3 with mean pore diameters of 450 and 2700 nm, respectively. The particles were aggregates with average mobility diameters in the range of 30¨¢100 nm and primary particle...

  15. On the Origin of Elementary Particle Masses

    Directory of Open Access Journals (Sweden)

    Hansson J.

    2014-04-01

    Full Text Available The oldest enigma in fundamental particle physics is: Where do the observed masses of elementary particles come from? Inspired by observation of the empirical particle mass spectrum we propose that the masses of elementary parti cles arise solely due to the self-interaction of the fields associated with a particle. We thus assume that the mass is proportional to the strength of the interaction of th e field with itself. A simple application of this idea to the fermions is seen to yield a mas s for the neutrino in line with constraints from direct experimental upper limits and correct order of magnitude predictions of mass separations between neutrinos, charge d leptons and quarks. The neutrino interacts only through the weak force, hence becom es light. The electron in- teracts also via electromagnetism and accordingly becomes heavier. The quarks also have strong interactions and become heavy. The photon is the only fundamental parti- cle to remain massless, as it is chargeless. Gluons gain mass comparable to quarks, or slightly larger due to a somewhat larger color charge. Inclu ding particles outside the standard model proper, gravitons are not exactly massless, but very light due to their very weak self-interaction. Some immediate and physically interesting consequences arise: i Gluons have an e ff ective range ∼ 1 fm, physically explaining why QCD has finite reach; ii Gravity has an effective range ∼ 100 Mpc coinciding with the largest known structures, the cosmic voids; iii Gravitational waves undergo dispersion even in vacuum, and have all five polarizations (not just the two of m = 0, which might explain why they have not yet been detected.

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

    Directory of Open Access Journals (Sweden)

    Daniel J Cooney

    2008-08-01

    Full Text Available Daniel J Cooney1, Anthony J Hickey21Department of Biomedical Engineering; 2School of Pharmacy, University of North Carolina, Chapel Hill, NC, USAAbstract: The influence of diesel exhaust particles (DEP on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene in the particles resulting from the aerosolization process.Keywords: diesel exhaust particles, aerosol, inhalation toxicology

  17. Particle size distribution of the stratospheric aerosol from SCIAMACHY limb measurements

    Science.gov (United States)

    Rozanov, Alexei; Malinina, Elizaveta; Rozanov, Vladimir; Hommel, Rene; Burrows, John

    2016-04-01

    Stratospheric aerosols are of a great scientific interest because of their crucial role in the Earth's radiative budget as well as their contribution to chemical processes resulting in ozone depletion. While the permanent aerosol background in the stratosphere is determined by the tropical injection of SO2, COS and sulphate particles from the troposphere, major perturbations of the stratospheric aerosol layer result form an uplift of SO2 after strong volcanic eruptions. Satellite measurements in the visible spectral range represent one of the most important sources of information about the vertical distribution of the stratospheric aerosol on the global scale. This study employs measurements of the scattered solar light performed in the limb viewing geometry from the space borne spectrometer SCIAMACHY, which operated onboard the ENVISAT satellite, from August 2002 to April 2012. A retrieval approach to obtain parameters of the stratospheric aerosol particle size distribution will be reported along with the sensitivity studies and first results.

  18. Mass Spectrometric Analysis of Pristine Aerosol Particles During the wet Season of Amazonia - Detection of Primary Biological Particles?

    Science.gov (United States)

    Schneider, J.; Zorn, S. R.; Freutel, F.; Borrmann, S.; Chen, Q.; Farmer, D. K.; Jimenez, J. L.; Flores, M.; Roldin, P.; Artaxo, P.; Martin, S. T.

    2008-12-01

    The contribution of primary biological aerosol (POA) particles to the natural organic aerosol is a subject of current research. Estimations of the POA contribution to the total aerosol particle concentration range between 25 and 80%, depending on location and season. Especially in the tropical rain forest it is expected that POA is a major source of supermicron, possibly also of submicron particles. During AMAZE (Amazonian Aerosol CharacteriZation Experiment), a field project near Manaus, Brazil, in February/March 2008, an Aerodyne ToF-AMS was equipped with a high pressure aerodynamic lens. This high pressure lens (operating pressure 14.6 torr) is designed with the objective to extend the detectable size range of the AMS into the supermicron size range where primary biological particles are expected. Size distribution measured by the AMS were compared with size distribution from an optical particle counter and indicate that the high pressure lens has a 50% cut-off at a vacuum aerodynamic diameter of about 1 μm, but still has significant transmission up to a vacuum aerodynamic diameter of about 2 μm, thus extending the detectable size range of the AMS into the coarse mode. The measuring instruments were situated in a container at ground level. The aerosol was sampled through a 40 m vertical, laminar inlet, which was heated and dried to maintain a relative humidity between 30 and 40%. The inlet was equipped with a 7 μm cut-off cyclone. Size distributions recorded with an optical particle counter parallel to the AMS show that the inlet transmitted aerosol particles up to an optically detected diameter of 10 μm. POA particles like plant fragments, pollen, spores, fungi, viruses etc. contain chemical compounds as proteins, sugars, amino acids, chlorophyll, and cellular material as cellulose. Laboratory experiments have been performed in order to identify typical mass spectral patterns of these compounds. These laboratory data were compared to size resolved particle

  19. Comparison between CARIBIC aerosol samples analysed by accelerator-based methods and optical particle counter measurements

    Directory of Open Access Journals (Sweden)

    B. G. Martinsson

    2014-04-01

    Full Text Available Inter-comparison of results from two kinds of aerosol systems in the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container passenger aircraft based observatory, operating during intercontinental flights at 9–12 km altitude, is presented. Aerosol from the lowermost stratosphere (LMS, the extra-tropical upper troposphere (UT and the tropical mid troposphere (MT were investigated. Aerosol particle volume concentration measured with an optical particle counter (OPC is compared with analytical results of the sum of masses of all major and several minor constituents from aerosol samples collected with an impactor. Analyses were undertaken with accelerator-based methods particle-induced X-ray emission (PIXE and particle elastic scattering analysis (PESA. Data from 48 flights during one year are used, leading to a total of 106 individual comparisons. The ratios of the particle volume from the OPC and the total mass from the analyses were in 84% within a relatively narrow interval. Data points outside this interval are connected with inlet-related effects in clouds, large variability in aerosol composition, particle size distribution effects and some cases of non-ideal sampling. Overall, the comparison of these two CARIBIC measurements based on vastly different methods show good agreement, implying that the chemical and size information can be combined in studies of the MT/UT/LMS aerosol.

  20. Vertical Transport of Aerosol Particles across Mountain Topography near the Los Angeles Basin

    Science.gov (United States)

    Murray, J. J.; Schill, S.; Freeman, S.; Bertram, T. H.; Lefer, B. L.

    2015-12-01

    Transport of aerosol particles is known to affect air quality and is largely dependent on the characteristic topography of the surrounding region. To characterize this transport, aerosol number distributions were collected with an Ultra-High Sensitivity Aerosol Spectrometer (UHSAS, DMT) during the 2015 NASA Student Airborne Research Program (SARP) in and around the Los Angeles Basin in Southern California. Increases in particle number concentration and size were observed over mountainous terrain north of Los Angeles County. Chemical analysis and meteorological lagrangian trajectories suggest orographic lifting processes, known as the "chimney effect". Implications for spatial transport and distribution will be discussed.

  1. Study of real time detection and size distribution measurement of ultrafine aerosol with a particle growth system (PGS)

    Energy Technology Data Exchange (ETDEWEB)

    Rebours, A.

    1994-06-29

    First, the theoretical knowledge on condensation phenomena of a supersaturated vapor in a cylindrical duct where an ultrafine aerosol of nanometers size is flowing, is recalled. Then, a Particle Growth-System (PGS) of original design is developed: the aerosol is confined in a region with a uniform vapor supersaturation profile. When imperfectly filtered atmospheric air is used as source of condensation nuclei, the produced droplets are found to be monodisperse. Therefore, our PGS offers a simple method of calibrating Optical Particle Counters because the size distribution of theses droplets is controlled. After an experimental study validated by a theoretical model, we establish that, under certain supersaturation conditions, the droplet size in our PGS is a function of ultrafine particle size on which the vapor condenses. Furthermore, when the sampled aerosol is constituted of an ultrafine fraction and a fine fraction, we show that the size distribution of the droplets that come out from the PGS is bimodal too. Finally, a simple redesign of our fluids inlet system should reduce particles losses in the PGS due to brownian diffusion and, in that manner improve their detection. (author). 72 refs., 46 figs., 8 tabs., 4 appends.

  2. The effects of mineral dust particles, aerosol regeneration and ice nucleation parameterizations on clouds and precipitation

    Directory of Open Access Journals (Sweden)

    A. Teller

    2012-03-01

    Full Text Available This study focuses on the effects of aerosol particles on the formation of convective clouds and precipitation in the Eastern Mediterranean sea with a special emphasis on the role of mineral dust particles in these processes. We used a new detailed numerical cloud microphysics scheme that has been implemented in the Weather Research and Forecast (WRF model in order to study aerosol-cloud interaction in 3-D configuration based on realistic meteorological data. Using a number of case studies we tested the contribution of mineral dust particles and different ice nucleation parameterizations to precipitation development. In this study we also investigated the importance of recycled (regenerated aerosols that had been released to the atmosphere following the evaporation of cloud droplets.

    The results showed that increased aerosol concentration due to the presence of mineral dust enhanced the formation of ice crystals. The dynamic evolution of the cloud system sets the time periods and regions in which heavy or light precipitation occurred in the domain. The precipitation rate, the time and duration of precipitation were affected by the aerosol properties only at small area scales (with areas of about 20 km2. Changes of the ice nucleation scheme from ice supersaturation dependent parameterization to a recent approach of aerosol concentration and temperature dependent parameterization modified the ice crystals concentrations but did not affect the total precipitation in the domain. Aerosol regeneration modified the concentration of cloud droplets at cloud base by dynamic recirculation of the aerosols but also had only a minor effect on precipitation.

    The major conclusion from this study is that the effect of mineral dust particles on clouds and total precipitation is limited by the properties of the atmospheric dynamics and the only effect of aerosol on precipitation may come from significant increase in the concentration

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

    Science.gov (United States)

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

    2013-12-01

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

  4. Changes in background aerosol composition in Finland during polluted and clean periods studied by TEM/EDX individual particle analysis

    Directory of Open Access Journals (Sweden)

    J. V. Niemi

    2006-01-01

    Full Text Available Aerosol samples were collected at a rural background site in southern Finland in May 2004 during pollution episode (PM1~16 µg m−3, backward air mass trajectories from south-east, intermediate period (PM1~5 µg m−3, backtrajectories from north-east and clean period (PM1~2 µg m−3, backtrajectories from north-west/north. The elemental composition, morphology and mixing state of individual aerosol particles in three size fractions were studied using transmission electron microscopy (TEM coupled with energy dispersive X-ray (EDX microanalyses. The TEM/EDX results were complemented with the size-segregated bulk chemical measurements of selected ions and organic and elemental carbon. Many of the particles in PM0.2–1 and PM1–3.3 size fractions were strongly internally mixed with S, C and/or N. The major particle types in PM0.2–1 samples were 1 soot and 2 (ammoniumsulphates and their mixtures with variable amounts of C, K, soot and/or other inclusions. Number proportions of those two particle groups in PM0.2–1 samples were 0–12% and 83–97%, respectively. During the pollution episode, the proportion of Ca-rich particles was very high (26–48% in the PM1–3.3 and PM3.3–11 samples, while the PM0.2–1 and PM1–3.3 samples contained elevated proportions of silicates (22–33%, metal oxides/hydroxides (1–9% and tar balls (1–4%. These aerosols originated mainly from polluted areas of Eastern Europe, and some open biomass burning smoke was also brought by long-range transport. During the clean period, when air masses arrived from the Arctic Ocean, PM1–3.3 samples contained mainly sea salt particles (67–89% with a variable rate of Cl substitution (mainly by NO3−. During the intermediate period, the PM1–3.3 sample contained porous (sponge-like Na-rich particles (35% with abundant S, K and O. They might originate from the burning of wood pulp wastes of paper industry. The proportion of biological particles and C-rich fragments

  5. Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol.

    Directory of Open Access Journals (Sweden)

    Monique Williams

    Full Text Available Electronic cigarettes (EC deliver aerosol by heating fluid containing nicotine. Cartomizer EC combine the fluid chamber and heating element in a single unit. Because EC do not burn tobacco, they may be safer than conventional cigarettes. Their use is rapidly increasing worldwide with little prior testing of their aerosol.We tested the hypothesis that EC aerosol contains metals derived from various components in EC.Cartomizer contents and aerosols were analyzed using light and electron microscopy, cytotoxicity testing, x-ray microanalysis, particle counting, and inductively coupled plasma optical emission spectrometry.The filament, a nickel-chromium wire, was coupled to a thicker copper wire coated with silver. The silver coating was sometimes missing. Four tin solder joints attached the wires to each other and coupled the copper/silver wire to the air tube and mouthpiece. All cartomizers had evidence of use before packaging (burn spots on the fibers and electrophoretic movement of fluid in the fibers. Fibers in two cartomizers had green deposits that contained copper. Centrifugation of the fibers produced large pellets containing tin. Tin particles and tin whiskers were identified in cartridge fluid and outer fibers. Cartomizer fluid with tin particles was cytotoxic in assays using human pulmonary fibroblasts. The aerosol contained particles >1 µm comprised of tin, silver, iron, nickel, aluminum, and silicate and nanoparticles (<100 nm of tin, chromium and nickel. The concentrations of nine of eleven elements in EC aerosol were higher than or equal to the corresponding concentrations in conventional cigarette smoke. Many of the elements identified in EC aerosol are known to cause respiratory distress and disease.The presence of metal and silicate particles in cartomizer aerosol demonstrates the need for improved quality control in EC design and manufacture and studies on how EC aerosol impacts the health of users and bystanders.

  6. Particle Characterization and Ice Nucleation Efficiency of Field-Collected Aerosol Particles

    Science.gov (United States)

    Wang, B.; Gilles, M. K.; Laskin, A.; Moffet, R.; Nizkorodov, S.; Roedel, T.; Sterckx, L.; Tivanski, A.; Knopf, D. A.

    2011-12-01

    Atmospheric ice formation by heterogeneous nucleation is one of the least understood processes resulting in cirrus and mixed-phase clouds which affect the global radiation budget, the hydrological cycle, and water vapor distribution. In particular, how organic aerosol affect ice nucleation is not well understood. Here we report on heterogeneous ice nucleation from particles collected during the CalNex campaign at the Caltech campus site, Pasadena, on May 19, 2010 at 6am-12pm (A2) and 12pm-6pm (A3) and May 23 at 6am-12pm (B2) and 6pm-12am (B4). The ice nucleation onsets and water uptake were determined as a function of temperature (200-273 K) and relative humidity with respect to ice (RHice). The ice nucleation efficiency was related to the particle chemical composition. Single particle characterization was provided by using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). The STXM/NEXAFS analysis indicates that the morning sample (A2) constitutes organic particles and organic particles with soot and inorganic inclusions. The afternoon sample (A3) is dominated by organic particles with a potentially higher degree of oxidation associated with soot. The B2 sample shows a higher number fraction of magnesium-containing particle indicative of a marine source and ~93% of the particles contained sulfur besides oxygen and carbon as derived from CCSEM/EDX analysis. The B4 sample lacks the strong marine influence and shows higher organic content. Above 230 K, we observed water uptake followed by condensation freezing at mean RH of 93-100% and 89-95% for A2 and A3, respectively. This indicates that the aged A3 particles are efficient ice nuclei (IN) for condensation freezing. Below 230 K A2 and A3 induced deposition ice nucleation between 125-155% RHice (at mean values of 134-150% RHice). The B2 and B4

  7. Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe

    Directory of Open Access Journals (Sweden)

    T. Hamburger

    2012-12-01

    Full Text Available In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm−3 stp. Ultra-fine particles as indicators for nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.

  8. Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe

    Science.gov (United States)

    Hamburger, T.; McMeeking, G.; Minikin, A.; Petzold, A.; Coe, H.; Krejci, R.

    2012-12-01

    In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm-3 stp. Ultra-fine particles as indicators for nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C) to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.

  9. SPM analysis on groups of single aerosol particles around steel plant

    Institute of Scientific and Technical Information of China (English)

    沙因; 王安璞; 等

    1996-01-01

    Several methods for preparing samples of dispersed single aeroslo particles used in scanning proton microprobe(SPM) analysis were tested.Many elements such as Al,Si,S,Cl,Ca,Ti,Cr,Mn,Fe,Ni,Cu and Zn in the groups of different single aerosol particles from the Capital Steel Plant area were analyzed by SPM,The distributions of elemental contents in the group of single particles were mapped with three dimensional contour and the isometric.A new approach to study the group of different single aerosol particles for air pollution is developed in the present work.The results are significant to assessing the environmental impact of the dispersed single aerosol particles.

  10. Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2011-06-01

    Full Text Available The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES project to study the effect of seed particles on the formation of secondary organic aerosol (SOA from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulfate or diesel particles, a method was developed to use in-situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m−3. Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8 %. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90 % RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC × GC and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

  11. Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

    Directory of Open Access Journals (Sweden)

    J. F. Hamilton

    2010-10-01

    Full Text Available The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES project to study the effect of seed particles on the formation of secondary organic aerosol (SOA from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulphate or diesel particles, a method was developed to use in situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m-3. Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8%. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90% RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC×GC and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

  12. Particle Morphology and Size Results from the Smoke Aerosol Measurement Experiment-2

    Science.gov (United States)

    Urban, David L.; Ruff, Gary A.; Greenberg, Paul S.; Fischer, David; Meyer, Marit; Mulholland, George; Yuan, Zeng-Guang; Bryg, Victoria; Cleary, Thomas; Yang, Jiann

    2012-01-01

    Results are presented from the Reflight of the Smoke Aerosol Measurement Experiment (SAME-2) which was conducted during Expedition 24 (July-September 2010). The reflight experiment built upon the results of the original flight during Expedition 15 by adding diagnostic measurements and expanding the test matrix. Five different materials representative of those found in spacecraft (Teflon, Kapton, cotton, silicone rubber and Pyrell) were heated to temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow. The air flow past the sample during the heating period ranged from quiescent to 8 cm/s. The smoke was initially collected in an aging chamber to simulate the transport time from the smoke source to the detector. This effective transport time was varied by holding the smoke in the aging chamber for times ranging from 11 to 1800 s. Smoke particle samples were collected on Transmission Electron Microscope (TEM) grids for post-flight analysis. The TEM grids were analyzed to observe the particle morphology and size parameters. The diagnostics included a prototype two-moment smoke detector and three different measures of moments of the particle size distribution. These moment diagnostics were used to determine the particle number concentration (zeroth moment), the diameter concentration (first moment), and the mass concentration (third moment). These statistics were combined to determine the diameter of average mass and the count mean diameter and, by assuming a log-normal distribution, the geometric mean diameter and the geometric standard deviations can also be calculated. Overall the majority of the average smoke particle sizes were found to be in the 200 nm to 400 nm range with the quiescent cases producing some cases with substantially larger particles.

  13. Number-size distribution of aerosol particles and new particle formation events in tropical and subtropical Pacific Oceans

    Science.gov (United States)

    Ueda, S.; Miura, K.; Kawata, R.; Furutani, H.; Uematsu, M.; Omori, Y.; Tanimoto, H.

    2016-10-01

    Number-size distributions of aerosol particles with diameters of 10-500 nm in the marine boundary layer were observed continually onboard the R/V Hakuho Maru over the equatorial and subtropical North Pacific and South Pacific during December 2011-March 2012. Number-size distributions over each area were parameterized using a sum of up to three lognormal functions. Bi-modal size distributions with peak diameters at 30-80 nm (Aitken mode) and 100-200 nm (accumulation mode) were observed frequently. Larger peak diameters of Aitken and accumulation modes were observed over the eastern equator, where 5-day backward trajectories showed that the air masses had derived from high-chlorophyll oceanic regions without precipitation. Smaller peak diameters and low concentrations were often observed over the North Pacific. The trajectories show that such air mass originated from oceanic regions with less chlorophyll, exhibiting high precipitation frequency. New particle formation (NPF) events have often been observed over the mid-latitude eastern South Pacific with a low condensation sink (CS) and some dimethyl sulfide, although none was observed over the equator, where CS was higher. The lesser CS condition at NPF events was mostly correlated with local precipitation or precipitation along the trajectories within 1 day. These results suggest that differences of the number-size distribution and occasions of NPF events among sea areas most closely accord with precipitation along the trajectories.

  14. Complexation of trace metals in size-segregated aerosol particles at nine sites in Germany

    Science.gov (United States)

    Scheinhardt, Sebastian; Müller, Konrad; Spindler, Gerald; Herrmann, Hartmut

    2013-08-01

    The complexation of trace metal ions (TMI) was studied in size-segregated ambient aerosol particles collected at nine sites in Germany (urban, rural and coastal). Samples were analysed in terms of TMI (Fe, Mn, Cu), potential inorganic and organic ligands and pH. Using a thermodynamic model (E-AIM III), the concentrations of these compounds in the particle liquid phase were estimated. The resulting liquid phase concentrations were then used as input parameters for a speciation model (Visual MINTEQ) and the equilibrium complexation was calculated under realistic conditions. The complexation was found to be controlled by the availability of strong organic ligands, especially oxalate, whose occurrence in turn was governed by the formation of insoluble Ca-oxalate. Likewise, the pH influenced oxalate availability because it alters the concentrations of the chelating mono- and dianions. As a qualitative result, Fe3+ was found to be mainly complexed by oxalate, while Fe2+ and Mn2+ were rather associated with nitrate. Cu2+ showed mixed organic and nitrate complexation. Complexation by HULIS was only significant for Fe3+ and Cu2+ and was generally less important than other ligands like oxalate and nitrate. Oxalate was found to exist mainly in the solid phase while higher dicarboxylic acids mostly did not form complexes due to protonation. Complexation was shown to be influenced by season, air mass origin, particle size and sampling site.

  15. NUMBER CONCENTRATION, SIZE DISTRIBUTION AND FINE PARTICLE FRACTION OF TROPOSPHERIC AND STRATOSPHERIC AEROSOLS

    Institute of Scientific and Technical Information of China (English)

    Li Xu; Guangyu Shi; Li Zhang; Jun Zhou; Yasunobu Iwasaka

    2003-01-01

    Aerosol observations were carried out at Xianghe Scientific Balloon Base (39.45°N, 117°E) using a stratospheric balloon. The particle number concentrations of the tropospheric and stratospheric aerosols were directly explored.The vertical distributions of the number concentration, number-size (that is, particle number versus particle size)distribution, and the fraction of fine particles (0.5 μm>r>0.15 μm/r>0.15 μm) are reported in this paper. The profiles of particle concentration present multi-peak phenomenon. The pattern of size distribution for atmospheric aerosol indicates a tri-modal (r=~0.2 μm, ~0.88 μm and ~7.0 μm) and a bi-modal (r=~0.13 μm and 2.0 μm). The number-size distribution almost fits the Junge distribution for particles with r<0.5 μm in the stratosphere of 1993 and the troposphere of 1994. But the distributions of coarse particles (r>0.5 μm) are not uniform. The number-size distribution exhibits also a wide size range in the troposphere of 1993. The results demonstrate that fine particles represent the major portion in the troposphere during the measurement period, reaching as high as 95% in 1994. Certain coarse particle peaks in the troposphere were attributed to clouds and other causes, and in the stratosphere to volcanic eruption. The stratospheric aerosol layer consists of unique fractions of fine or coarse particles depending on their sources. In summary, the process of gas-to-particles conversion was active and the coarse particles were rich over the Xianghe area. The measurements also demonstrate that the spatial and temporal atmospheric aerosol distributions are nonuniform and changeful.

  16. Trace element composition and origin of the atmospheric aerosol in the Norwegian arctic

    Science.gov (United States)

    Maenhaut, Willy; Cornille, Philippe; Pacyna, Jozef M.; Vitols, Val

    Ninety-eight filter samples of airborne As, Se and In at Vardø. The Ny Ålesund aerosol data were subjected to chemical mass balance source apportionment, using a seven- or eight-element tracer system and regional signatures from eastern North America, Europe and the U.S.S.R. The results indicated that only 10% of the mass of the tracer elements came from eastern North America, and that the U.S.S.R. and Europe contributed in a 60/40 proportion during winter and in a 25/75 proportion in summer. Only 12% of the airborne Se, observed at Ny Alesund in summer, could be attributed to the Eurasian source regions. Evidence is presented that the unexplained Se has a marine, biogenic origin. Arguments are also given to suggest that a sizeable fraction, perhaps up to 50%, of the non-sea-salt sulfate at Ny Ålesund in summer results from gas-to-particle conversion of biogenic, reduced gaseous sulfur species, such as dimethyl sulfide, which are released by the oceans.

  17. On the potential contribution of open lead particle emissions to the central Arctic aerosol concentration

    Directory of Open Access Journals (Sweden)

    A. Held

    2010-10-01

    Full Text Available During the ice-breaker borne ASCOS expedition (Arctic Summer Cloud Ocean Study direct eddy covariance measurements of aerosol number fluxes were carried out in August 2008 on the edge of an ice floe drifting in the central Arctic Ocean between 2°–10° W longitude and 87°–87.5° N latitude. The median aerosol transfer velocities over different surface types (open water leads, ice ridges, snow and ice surfaces ranged from 0.27 to 0.68 mm s−1 during deposition-dominated episodes. Emission periods were observed more frequently over the open lead, while the snow behaved primarily as a deposition surface. Directly measured aerosol fluxes were compared with particle deposition parameterizations in order to estimate the emission flux from the observed net aerosol flux. Finally, the contribution of the open lead particle source to atmospheric variations in particle number concentration was evaluated and compared with the observed temporal evolution of particle number. The direct emission of aerosol particles from the open lead can only explain 5–10% of the observed particle number variation in the mixing layer close to the surface.

  18. Hygroscopicity of aerosol particles and CCN activity of nearly hydrophobic particles in the urban atmosphere over Japan during summer

    Science.gov (United States)

    Ogawa, Shuhei; Setoguchi, Yoshitaka; Kawana, Kaori; Nakayama, Tomoki; Ikeda, Yuka; Sawada, Yuuki; Matsumi, Yutaka; Mochida, Michihiro

    2016-06-01

    We investigated the hygroscopicity of 150 nm particles and the number-size distributions and the cloud condensation nuclei (CCN) activity of nearly hydrophobic particles in aerosols over Nagoya, Japan, during summer. We analyzed the correlations between the number concentrations of particles in specific hygroscopic growth factor (g) ranges and the mass concentrations of chemical components. This analysis suggests the association of nearly hydrophobic particles with hydrocarbon-like organic aerosol, elemental carbon and semivolatile oxygenated organic aerosol (SV-OOA), that of less hygroscopic particles with SV-OOA and nitrate and that of more hygroscopic particles with low-volatile oxygenated organic aerosol (LV-OOA) and sulfate. The hygroscopicity parameter (κ) of organics was derived based on the g distributions and chemical composition of 150 nm particles. The κ of the organics correlated positively with the fraction of the total organic mass spectral signal at m/z 44 and the volume fraction of the LV-OOA to the organics, indicating that organics with highly oxygenated structures including carboxylic acid groups contribute to the water uptake. The number-size distributions of the nearly hydrophobic particles with g around 1.0 and 1.1 correlated with the mass concentrations of chemical components. The results show that the chemical composition of the particles with g around 1.0 was different between the Aitken mode and the accumulation mode size ranges. An analysis for a parameter Fmax of the curves fitted to the CCN efficiency spectra of the particles with g around 1.0 suggests that the coating by organics associated with SV-OOA elevated the CCN activity of these particles.

  19. Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe

    Directory of Open Access Journals (Sweden)

    T. Hamburger

    2012-08-01

    Full Text Available In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm−3 stp. Nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.

  20. Real-time detection of individual secondary organic aerosol particle from photooxidation of toluene using aerosol time of flight mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenya; HAO Liqing; ZHOU Liuzhu; GUO Xiaoyong; ZHAO Wenwu; FANG Li; ZHANG Weijun

    2006-01-01

    Photooxidation of the aromatic hydrocarbon toluene and its subsequent reactions were carried out using UV-irradiation of toluene/CH3ONO/NO/air mixtures in a home-made smog chamber.The secondary organic aerosols could be formed after those oxidation products of semi-volatile or-ganic compounds were partitioned between gas phase and particle phase. The aerosol time of flight mass spectrometer (ATOFMS) was used to measure size and molecular composition of individual secondary organic aerosol particle. Size distribution and chemical composition of secondary organic aerosol were got in real time.

  1. Size distribution of the secondary organic aerosol particles from the photooxidation of toluene

    Institute of Scientific and Technical Information of China (English)

    HAO Li-qing; WANG Zhen-ya; HUANG Ming-qiang; PEI Shi-xin; YANG Yong; ZHANG Wei-jun

    2005-01-01

    In a smog chamber, the photooxidation of toluene was initiated by hydroxyl radical (OH·) under different experimental conditions. The size distribution of secondary organic aerosol(SOA) particles from the above reaction was measured using aerodynamic particle sizer spectrometer. It was found from our experimental results that the number of SOA particles increased with increasing the concentration of toluene. As the reaction time prolonged, the sum of SOA particles was also increased. After a reaction time of 130 min,the concentration of secondary organic aerosol particles would be kept constant at 2300 particles/cm3 . Increasing illumination power of blacklamps could significantly induce a higher concentration of secondary organic aerosol particle. The density of SOA particles would also be increased with increasing concentration of CH3 ONO, however, it would be decreased as soon as the concentration of CH3 ONO was larger than 225.2 ppm. Nitrogen oxide with initial concentration higher than 30.1 ppm was also found to have little effect on the formation of secondary organic aerosol.

  2. An overview of differential mobility analyzers for size classification of nanometer-sized aerosol particles

    Directory of Open Access Journals (Sweden)

    Nakorn Tippayawong

    2008-03-01

    Full Text Available Size classification of nanoparticles is an important process in the electrical mobility particle size analyzer. The differential mobility analyzer (DMA is one of the most commonly used devices for classifying and measuring nanometersized aerosol particles between 1 nm to 1 μm in diameter, based on their electrical mobility. The DMA can be described as an assembly of two concentrically cylindrical electrodes with an air gap between the walls. In the DMA, air and aerosol flows enter from one end, pass through the annulus and exit the other end. An electric field is applied between the inner and outer electrodes. Particles having a specific mobility exit with the monodisperse air flow through a small slit located at the bottom of the inner electrode. These particles are transferred to a particle counter to determine the particle number concentration. In the past several decades, there have been numerous extensive studies and developments on the DMA. Nonetheless, they are different in terms of specific applications, construction, particle size range, as well as time response and resolution. The purpose of this article is to provide an overview of the state-of-the-art existing cylindrical DMAs for aerosol particle size classification as well as for the generation of monodisperse aerosol in nanometer size range. A description of the operating principles, detailed physical characteristics of these DMAs, including the single-channel and multi-channel DMAs, as well as some examples of applications to nanotechnology are given.

  3. Quantification of bitumen particles in aerosol and soil samples using HP-GPC

    DEFF Research Database (Denmark)

    Fauser, Patrik; Tjell, Jens Christian; Mosbæk, Hans;

    2000-01-01

    A method for identifying and quantifying bitumen particles, generated from the wear of roadway asphalts, in aerosol and soil samples has been developed. Bitumen is found to be the only contributor to airborne particles containing organic molecules with molecular weights larger than 2000 g pr. mol...

  4. Tire-tread and bitumen particle concentrations in aerosol and soil samples

    DEFF Research Database (Denmark)

    Fauser, Patrik; Tjell, Jens Christian; Mosbæk, Hans;

    2002-01-01

    ire and bitumen particle concentrations are determined in aerosol and soil samples. They each constitute about 5 wt-% of the total suspended particulate matter (TSP) in inner city air, collected with a Berner low pressure impactor, 5 m from a road. The particle size distribution shows that 92% of...

  5. Glyoxal processing by aerosol multiphase chemistry: towards a kinetic modeling framework of secondary organic aerosol formation in aqueous particles

    Directory of Open Access Journals (Sweden)

    B. Ervens

    2010-09-01

    Full Text Available This study presents a modeling framework based on laboratory data to describe the kinetics of glyoxal reactions that form secondary organic aerosol (SOA in aqueous aerosol particles. Recent laboratory results on glyoxal reactions are reviewed and a consistent set of empirical reaction rate constants is derived that captures the kinetics of glyoxal hydration and subsequent reversible and irreversible reactions in aqueous inorganic and water-soluble organic aerosol seeds. Products of these processes include (a oligomers, (b nitrogen-containing products, (c photochemical oxidation products with high molecular weight. These additional aqueous phase processes enhance the SOA formation rate in particles and yield two to three orders of magnitude more SOA than predicted based on reaction schemes for dilute aqueous phase (cloud chemistry for the same conditions (liquid water content, particle size.

    The application of the new module including detailed chemical processes in a box model demonstrates that both the time scale to reach aqueous phase equilibria and the choice of rate constants of irreversible reactions have a pronounced effect on the predicted atmospheric relevance of SOA formation from glyoxal. During day time, a photochemical (most likely radical-initiated process is the major SOA formation pathway forming ∼5 μg m−3 SOA over 12 h (assuming a constant glyoxal mixing ratio of 300 ppt. During night time, reactions of nitrogen-containing compounds (ammonium, amines, amino acids contribute most to the predicted SOA mass; however, the absolute predicted SOA masses are reduced by an order of magnitude as compared to day time production. The contribution of the ammonium reaction significantly increases in moderately acidic or neutral particles (5 < pH < 7.

    Glyoxal uptake into ammonium sulfate seed under dark conditions can be represented with a single reaction parameter keffupt that does not depend

  6. LOAC (Light Optical Particle Counter): a new small aerosol counter with particle characterization capabilities for surface and airborne measurements

    Science.gov (United States)

    Renard, Jean-Baptiste; Berthet, Gwenael; Jégou, Fabrice; Jeannot, Matthieu; Jourdain, Line; Dulac, François; Mallet, Marc; Dupont, Jean-Charles; Thaury, Claire; Tonnelier, Thierry; Verdier, Nicolas; Charpentier, Patrick

    2013-04-01

    The determination of the size distribution of tropospheric and stratospheric aerosols with conventional optical counters is difficult when different natures of particles are present (droplets, soot, mineral dust, secondary organic or mineral particles...). Also, a light and cheap aerosol counter that can be used at ground, onboard drones or launched under all kinds of atmospheric balloons can be very useful during specific events as volcanic plumes, desert dust transport or local pollution episodes. These goals can be achieved thanks to a new generation of aerosol counter, called LOAC (Light Optical Aerosol Counter). The instrument was developed in the frame of a cooperation between French scientific laboratories (CNRS), the Environnement-SA and MeteoModem companies and the French Space Agency (CNES). LOAC is a small optical particle counter/sizer of ~250 grams, having a low electrical power consumption. The measurements are conducted at two scattering angles. The first one, at 12°, is used to determine the aerosol particle concentrations in 19 size classes within a diameter range of 0.3-100 micrometerers. At such an angle close to forward scattering, the signal is much more intense and the measurements are the least sensitive to the particle nature. The second angle is at 60°, where the scattered light is strongly dependent on the particle refractive index and thus on the nature of the aerosols. The ratio of the measurements at the two angles is used to discriminate between the different types of particles dominating the nature of the aerosol particles in the different size classes. The sensor particularly discriminates wet or liquid particles, soil dust and soot. Since 2011, we have operated LOAC in various environments (Arctic, Mediterranean, urban and peri-urban…) under different kinds of balloons including zero pressure stratospheric, tethered, drifting tropospheric, and meteorological sounding balloons. For the last case, the total weight of the gondola

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

    Science.gov (United States)

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

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

  8. The formation of aerosol particles during combustion of biomass and waste. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hjerrild Zeuthen, J.

    2007-05-15

    This thesis describes the formation of aerosol particles during combustion of biomass and waste. The formation of aerosol particles is investigated by studying condensation of alkali salts from synthetic flue gasses in a laboratory tubular furnace. In this so-called laminar flow aerosol condenser-furnace gaseous alkali chlorides are mixed with sulphur dioxide, water vapour and oxygen. At high temperatures the alkali chloride reacts with sulphur dioxide to form alkali sulphate. During subsequent cooling of the synthetic flue gas the chlorides and sulphates condense either as deposits on walls or on other particles or directly from the gas phase by homogenous nucleation. A previously developed computer code for simulation of one-component nucleation of particles in a cylindrical laminar flow is extended to include a homogeneous gas phase reaction to produce gaseous alkali sulphate. The formation of aerosol particles during full-scale combustion of wheat straw is investigated in a 100 MW grate-fired boiler. Finally, aerosols from incineration of waste are investigated during full-scale combustion of municipal waste in a 22 MW grate-fired unit. (BA)

  9. [Concentration and Particle Size Distribution of Microbiological Aerosol During Haze Days in Beijing].

    Science.gov (United States)

    Hu, Ling-fei; Zhang, Ke; Wang, Hong-bao; Li, Na; Wang, Jie; Yang, Wen-hui; Yin, Zhe; Jiao, Zhou-guang; Wen, Zhan-bo; Li, Jin-song

    2015-09-01

    In this study, we evaluated the bacterial, fungal aerosol concentration, and particle size distribution using microbiological aerosol sampler, and analyzed the particles count concentration of PM1.0, PM2.5, PM5.0 and PM10.0 using aerodynamic particle sizer during clear and haze days in Beijing during Jan 8th, 2013 to Feb 4th, 2013. The concentration of bacterial, fungal aerosol, air particulate matter and aerosol distribution were compared between haze days and clear days. Our results indicated that the proportion of fungal particles smaller than 5 micron, which could deposit in lungs or deeper regions, was much higher than bacterial particles. The biological concentration of bacteria and fungi were higher in clear days than in haze days, and there was no statistic difference of the microbiological aerosol distribution. The concentration of air particulate matter were higher in haze days than in clear days, PM10 was the main particulate matters both in clear days and haze days.

  10. Stratospheric aerosol particle size information in Odin-OSIRIS limb scatter spectra

    Directory of Open Access Journals (Sweden)

    L. A. Rieger

    2013-06-01

    Full Text Available The Optical Spectrograph and InfraRed Imaging System (OSIRIS on-board the Odin satellite has now taken over a decade of limb scatter measurements that have been used to retrieve the Version 5 stratospheric aerosol extinction product. This product is retrieved using a representative particle size distribution to calculate scattering cross sections and scattering phase functions for the forward model calculations. In this work the information content of OSIRIS measurements with respect to stratospheric aerosol is systematically examined for the purpose of retrieving particle size information along with the extinction coefficient. The benefit of using measurements at different wavelengths and scattering angles in the retrieval is studied and it is found that incorporation of the 1530 nm radiance measurement is key for a robust retrieval of particle size information. It is also found that using OSIRIS measurements at different solar geometries simultaneously provides little additional benefit. Based on these results, an improved aerosol retrieval algorithm is developed that couples the retrieval of aerosol extinction and mode radius of a log-normal particle size distribution. Comparison of these results with coincident measurements from SAGE III show agreement in retrieved extinction to within approximately 10% over the bulk of the aerosol layer, which is comparable to Version 5. The retrieved particle size, when converted to Ångström coefficient, shows good qualitative agreement with SAGE II measurements made at somewhat shorter wavelengths.

  11. 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.

  12. The response of reworked aerosols to climate through estimation of inter-particle forces

    OpenAIRE

    Assadi Langroudi, Arya; Jefferson, I.

    2016-01-01

    This paper describes the first use of inter-particle force measurement in reworked aerosols to better understand the mechanics of dust deflation and its consequent ecological ramifications. Dust is likely to carry hydrocarbons and micro-organisms including human pathogens and cultured microbes and thereby is a threat to plants, animals and human. Present-day global aerosol emissions are substantially greater than in 1850; however, the projected influx rates are highly disputable. This uncerta...

  13. TEM Study of Aerosol Particles in Brown Haze Episodes over Northern China in Spring 2007

    Science.gov (United States)

    Li, W.; Shao, L.; Buseck, P. R.

    2008-12-01

    Airborne aerosol collections were performed in eight brown haze episodes from 31 May to 21 June 2007 in Beijing, China. Morphologies, compositions, and mixing states of individual aerosol particles having different sizes were obtained using transmission electron microscopy (TEM). Aerosol particle types less than 2 μ m in diameter include mineral dust, fly ash, soot, organic material, and K-rich, S-rich, and metal particles (Fe- and Zn-rich). Mineral dust particles dominate in the range of 2 to 10 μ m. In addition to finding contributions from vehicle emissions and soil dust in Beijing, TEM results from the study provide new insights into sources such as agricultural biomass burning, industrial activities, and waste incineration. These sources can contribute not only great amounts of K-rich and metal particles but also reactive gases such as NH3, NOx, SO2, and VOCs to the haze. More than 80% of the analyzed aerosol particles are internally mixed. K- and S-rich particles tend to be coagulated with fly ash, soot, metal, and fine-grained mineral dust particles. Organic materials can act as inclusions in the K- and S-rich particles and their coatings. Over 90% of the analyzed internally mixed mineral particles are covered with Ca-, Mg-, or Na-rich coatings, and only 8% are associated with K- or S-rich coatings. The compositions of Ca-, Mg-, and Na-rich coatings suggest that they are possibly nitrates mixed with minor sulfates and chlorides. Calcium sulfate particles with diameters from 10 to 500 nm were also detected within Ca(NO3)2 and Mg(NO3)2 coatings. These results indicate that mineral dust particles in the brown haze episodes participated in heterogeneous reactions in the atmosphere with one or more of SO2, NO2, HCl, and HNO3. The development of coatings altered some mineral dust particles from hydrophobic to hydrophilic.

  14. Experimental and modeling studies on number and size spectrum evolutions of aerosol particles within a chamber

    Institute of Scientific and Technical Information of China (English)

    SUN Zai; HUANG Zhen; WANG JiaSong

    2007-01-01

    A size-specific aerosol dynamic model is set up to predict the evolution of particle number concentration within a chamber. Particle aggregation is based on the theory of Brownian coagulation, and the model not only comprises particle loss due to coagulation, but also considers the formation of large particles by collision. To validate the model, three different groups of chamber experiments with SMPS (Scanning Mobility Particle Sizer) are conducted. The results indicate that the advantage of the model over the past simple size bin model is its provision of detailed information of size spectrum evolution,and the results can be used to analyze the variations of number concentration and CMD (Count Median Diameter). Furthermore, some aerosol dynamic mechanisms that cannot be measured by instrument can be analyzed by the model simulation, which is significant for better understanding the removal and control mechanisms of ultrafine particles.

  15. Mixing state of particles with secondary species by single particle aerosol mass spectrometer in an atmospheric pollution event

    Science.gov (United States)

    Xu, Lingling; Chen, Jinsheng

    2016-04-01

    Single particle aerosol mass spectrometer (SPAMS) was used to characterize size distribution, chemical composition, and mixing state of particles in an atmospheric pollution event during 20 Oct. - 5 Nov., 2015 in Xiamen, Southeast China. A total of 533,012 particle mass spectra were obtained and clustered into six groups, comprising of industry metal (4.5%), dust particles (2.6%), carbonaceous species (70.7%), K-Rich particles (20.7%), seasalt (0.6%) and other particles (0.9%). Carbonaceous species were further divided into EC (70.6%), OC (28.5%), and mixed ECOC (0.9%). There were 61.7%, 58.3%, 4.0%, and 14.6% of particles internally mixed with sulfate, nitrate, ammonium and C2H3O, respectively, indicating that these particles had undergone significant aging processing. Sulfate was preferentially mixed with carbonaceous particles, while nitrate tended to mix with metal-containing and dust particles. Compared to clear days, the fractions of EC-, metal- and dust particles remarkably increased, while the fraction of OC-containing particles decreased in pollution days. The mixing state of particles, excepted for OC-containing particles with secondary species was much stronger in pollution days than that in clear days, which revealed the significant influence of secondary particles in atmospheric pollution. The different activity of OC-containing particles might be related to their much smaller aerodynamic diameter. These results could improve our understanding of aerosol characteristics and could be helpful to further investigate the atmospheric process of particles.

  16. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    Directory of Open Access Journals (Sweden)

    K. Adachi

    2008-11-01

    Full Text Available Soot particles, which are aggregated carbonaceous spherules with graphitic structures, are major aerosol constituents that result from burning of fossil fuel, biofuel, and biomass. Their properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using a transmission electron microscope (TEM for both imaging and chemical analysis, we measured ~8000 particles (25 samples with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC and adjacent areas. Most particles are coated, consist of aggregates, or both. For example, almost all analyzed particles contain S and 70% also contain K, suggesting coagulation and condensation of sulfates and particles derived from biomass and biofuel burning. In the MC plumes, over half of all particles contained soot coated by organic matter and sulfates. The median value of the soot volume fraction in such coated particles is about 15%. In contrast to the assumptions used in many climate models, the soot particles did not become compact even when coated. Moreover, about 80% by volume of the particles consisting of organic matter with sulfate also contained soot, indicating the important role of soot in the formation of secondary aerosol particles. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetimes. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate of MC than uncoated soot particles.

  17. Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2010-06-01

    Full Text Available Processes occurring in the tropical upper troposphere (UT, the Tropical Transition Layer (TTL, and the lower stratosphere (LS are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005, SCOUT-O3 (Darwin, Australia, December 2005, and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006. The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS, as well as relevant trace gases like N2O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are

  18. Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

    Science.gov (United States)

    Borrmann, S.; Kunkel, D.; Weigel, R.; Minikin, A.; Deshler, T.; Wilson, J. C.; Curtius, J.; Volk, C. M.; Homan, C. D.; Ulanovsky, A.; Ravegnani, F.; Viciani, S.; Shur, G. N.; Belyaev, G. V.; Law, K. S.; Cairo, F.

    2010-06-01

    Processes occurring in the tropical upper troposphere (UT), the Tropical Transition Layer (TTL), and the lower stratosphere (LS) are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ) measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005), SCOUT-O3 (Darwin, Australia, December 2005), and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006). The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS), as well as relevant trace gases like N2O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F) is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are compact enough to derive a

  19. Complex refractive index of aerosols during LACE 98 as derived from the analysis of individual particles

    Science.gov (United States)

    Ebert, , M.; Weinbruch, , S.; Rausch, , A.; Gorzawski, , G.; Helas, , G.; Hoffmann, , P.; Wex, H.

    2002-11-01

    During the Lindenberger Aerosol Characterization Experiment (LACE 98), impactor sampling of aerosol particles in the size range of 0.1 to 25 μm was performed. The atmospheric concentrations of the elements sodium to lead (11 ≤ Z ≤ 83) were determined by total reflection X-ray fluorescence analysis. Approximately 15,500 individual particles were examined by high-resolution scanning electron microscopy and energy-dispersive X-ray microanalysis, and about 3800 particles were examined by transmission electron microscopy combined with energy-dispersive X-ray microanalysis. On the basis of morphology and chemical composition the particles were classified into 10 different groups: ammonium sulfates, calcium sulfates, sea salt, metal oxides/hydroxides, carbonates, silicates, soot, biological particles, carbon/sulfate mixed particles, and rest of carbon-rich particles Crest. The phases present in the different particle groups were determined by selected area electron diffraction in the transmission electron microscope. In addition, the heterogeneous phase composition of agglomerates was studied in detail. On the basis of the size distribution and the relative abundance of the particle groups, the average and size-resolved complex refractive index of the total aerosol were calculated. The real part of the average refractive index mainly depends on the abundance of metal oxide/hydroxide particles and varied between 1.52 and 1.57 on the different sampling days. The average imaginary part varied between 0.031 and 0.057 depending on the amounts of soot and carbon/sulfate mixed particles. The average complex refractive index deduced from the analysis of individual aerosol particles is in good agreement with the results of photometer measurements of dried filter samples.

  20. Two-Photon Excited Fluorescence from Biological Aerosol Particles

    Science.gov (United States)

    2010-09-29

    previously observed from serotonin (5-HT) and its precursor hyrdroxytryptophan (5- HTP ) using multi-photon excitation [17-19]. Visible emission from...Sivaprakasam, A. Huston, H.B. Lin, J.D. Eversole, P. Falkenstein and A. Schultz, “Field test results and ambient aerosol measurements using dual

  1. Ice cloud processing of ultra-viscous/glassy aerosol particles leads to enhanced ice nucleation ability

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2012-09-01

    Full Text Available The ice nucleation potential of airborne glassy aqueous aerosol particles has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 247 and 216 K. Four different solutes were used as proxies for oxygenated organic matter found in the atmosphere: raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA, levoglucosan, and a multi-component mixture of raffinose with five dicarboxylic acids and ammonium sulphate. Similar to previous experiments with citric acid aerosols, all particles were found to nucleate ice heterogeneously before reaching the homogeneous freezing threshold provided that the freezing cycles were started well below the respective glass transition temperatures of the compounds; this is discussed in detail in a separate article. In this contribution, we identify a further mechanism by which glassy aerosols can promote ice nucleation below the homogeneous freezing limit. If the glassy aerosol particles are probed in freezing cycles started only a few degrees below their respective glass transition temperatures, they enter the liquid regime of the state diagram upon increasing relative humidity (moisture-induced glass-to-liquid transition before being able to act as heterogeneous ice nuclei. Ice formation then only occurs by homogeneous freezing at elevated supersaturation levels. When ice forms the remaining solution freeze concentrates and re-vitrifies. If these ice cloud processed glassy aerosol particles are then probed in a second freezing cycle at the same temperature, they catalyse ice formation at a supersaturation threshold between 5 and 30% with respect to ice. By analogy with the enhanced ice nucleation ability of insoluble ice nuclei like mineral dusts after they nucleate ice once, we refer to this phenomenon as pre-activation. We propose a number of possible explanations for why glassy aerosol particles that have re

  2. Ice cloud processing of ultra-viscous/glassy aerosol particles leads to enhanced ice nucleation ability

    Science.gov (United States)

    Wagner, R.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Skrotzki, J.; Leisner, T.; Wilson, T. W.; Malkin, T. L.; Murray, B. J.

    2012-09-01

    The ice nucleation potential of airborne glassy aqueous aerosol particles has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 247 and 216 K. Four different solutes were used as proxies for oxygenated organic matter found in the atmosphere: raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA), levoglucosan, and a multi-component mixture of raffinose with five dicarboxylic acids and ammonium sulphate. Similar to previous experiments with citric acid aerosols, all particles were found to nucleate ice heterogeneously before reaching the homogeneous freezing threshold provided that the freezing cycles were started well below the respective glass transition temperatures of the compounds; this is discussed in detail in a separate article. In this contribution, we identify a further mechanism by which glassy aerosols can promote ice nucleation below the homogeneous freezing limit. If the glassy aerosol particles are probed in freezing cycles started only a few degrees below their respective glass transition temperatures, they enter the liquid regime of the state diagram upon increasing relative humidity (moisture-induced glass-to-liquid transition) before being able to act as heterogeneous ice nuclei. Ice formation then only occurs by homogeneous freezing at elevated supersaturation levels. When ice forms the remaining solution freeze concentrates and re-vitrifies. If these ice cloud processed glassy aerosol particles are then probed in a second freezing cycle at the same temperature, they catalyse ice formation at a supersaturation threshold between 5 and 30% with respect to ice. By analogy with the enhanced ice nucleation ability of insoluble ice nuclei like mineral dusts after they nucleate ice once, we refer to this phenomenon as pre-activation. We propose a number of possible explanations for why glassy aerosol particles that have re-vitrified in contact

  3. Aerosol and Cloud-Nucleating Particle Observations during an Atmospheric River Event

    Science.gov (United States)

    DeMott, P. J.; McCluskey, C. S.; Petters, M.; Suski, K. J.; Levin, E. J.; Hill, T. C. J.; Atwood, S. A.; Schill, G. P.; Rocci, K.; Boose, Y.; Martin, A.; Cornwell, G.; Al-Mashat, H.; Moore, K.; Prather, K. A.; Rothfuss, N.; Taylor, H.; Leung, L. R.; Tomlinson, J. M.; Mei, F.; Hubbe, J. M.; Rosenfeld, D.; Spackman, J. R.; Fairall, C. W.; Creamean, J.; White, A. B.; Kreidenweis, S. M.

    2015-12-01

    The multi-agency CalWater 2015 project occurred over North Central CA and the Eastern Pacific during January to March 2015 (Spackman et al., this session). The goals of the campaign were to document the structure of atmospheric rivers (ARs) that deliver much of the water vapor associated with major winter storms along the U.S. West Coast and to investigate the modulating effect of aerosols on precipitation. Aerosol sources that may influence orographic cloud properties for air lifted over the mountains in California in winter include pollution, biomass burning, soil dusts and marine aerosols, but their roles will also be influenced by transport, vertical stratification, and scavenging processes. We present results from a comprehensive study of aerosol distributions, compositions, and cloud nucleating properties during an intense winter storm during February 2015, including data from an NSF-supported measurement site at Bodega Bay, from the DOE-ARM Cloud Aerosol Precipitation Experiment that included sampling on the NOAA RV Ron Brown offshore and the G-1 aircraft over ocean and land, and with context provided by other NOAA aircraft and remote sensing facilities. With a special focus on the coastal site, we discuss changes in aerosol distributions, aerosol hygroscopicity, and number concentrations of fluorescent particles, cloud condensation nuclei (CCN), and ice nucleating particles (INPs) during the AR event. We compare with periods preceding and following the event. For example, total aerosol number and surface area concentrations at below 0.5 μm diameter decreased from typical values of a few thousand cm-3 and 100 μm2 cm-3, respectively, to a few hundred cm-3 and 10 μm2cm-3 at Bodega Bay during the AR event. CCN concentrations were similarly lower, but hygroscopicity parameter (kappa) increased from typical values of 0.2 to values > 0.5 during the AR.INP and fluorescent particle number concentrations were generally lower during the AR event than at any other

  4. Nature, Origin, Potential Composition, and Climate Impact of the Asian Tropopause Aerosol Layer (ATAL)

    Science.gov (United States)

    Fairlie, T. D.; Vernier, J.-P.; Thomason, L. W.; Natarajan, M.; Bedka, K.; Wienhold, F.; Bian J.; Martinsson, B.

    2015-01-01

    Satellite observations from SAGE II and CALIPSO indicate that summertime aerosol extinction has more than doubled in the Asian Tropopause Aerosol Layer (ATAL) since the late 1990s. Here we show remote and in-situ observations, together with results from a chemical transport model (CTM), to explore the likely composition, origin, and radiative forcing of the ATAL. We show in-situ balloon measurements of aerosol backscatter, which support the high levels observed by CALIPSO since 2006. We also show in situ measurements from aircraft, which indicate a predominant carbonaceous contribution to the ATAL (Carbon/Sulfur ratios of 2- 10), which is supported by the CTM results. We show that the peak in ATAL aerosol lags by 1 month the peak in CO from MLS, associated with deep convection over Asia during the summer monsoon. This suggests that secondary formation and growth of aerosols in the upper troposphere on monthly timescales make a significant contribution to ATAL. Back trajectory calculations initialized from CALIPSO observations provide evidence that deep convection over India is a significant source for ATAL through the vertical transport of pollution to the upper troposphere.

  5. Development and experimental evaluation of an optical sensor for aerosol particle characterization

    Energy Technology Data Exchange (ETDEWEB)

    Somesfalean, G.

    1998-03-01

    A sensor for individual aerosol particle characterization, based on a single-mode semiconductor laser coupled to an external cavity is presented. The light emitting semiconductor laser acts as a sensitive optical detector itself, and the whole system has the advantage of using conventional optical components and providing a compact set-up. Aerosol particles moving through the sensing volume, which is located in the external cavity of a semiconductor laser, scatter and absorb light. Thereby they act as small disturbances on the electromagnetic field inside the dynamic multi-cavity laser system. From the temporal variation of the output light intensity, information about the number, velocity, size, and refractive index of the aerosol particles can be derived. The diffracted light in the near-forward scattering direction is collected and Fourier-transformed by a lens, and subsequently imaged on a CCD camera. The recorded Fraunhofer diffraction pattern provides information about the projected area of the scattering particle, and can thus be used to determine the size and the shape of aerosol particles. The sensor has been tested on fibers which are of interest in the field of working environment monitoring. The recorded output intensity variation has been analysed, and the relationship between the shape and the size of each fibre, and the resulting scattering profiles has been investigated. A simple one-dimensional model for the optical feedback variation due to the light-particle interaction in the external cavity is also discussed 34 refs, 26 figs, 6 tabs

  6. Classification of aerosol radiative properties during African desert dust intrusions over southeastern Spain by sector origins and cluster analysis

    Science.gov (United States)

    Valenzuela, A.; Olmo, F. J.; Lyamani, H.; Antón, M.; Quirantes, A.; Alados-Arboledas, L.

    2012-03-01

    The main goal of this study is to analyze the dependence of columnar aerosol optical and microphysical properties on source region and transport pathways during desert dust intrusions over Granada (Spain) from January 2005 to December 2010. Columnar aerosol properties have been derived from a non-spherical inversion code using the solar extinction measurements and sky radiances in the principal plane. Two classification methods of the African air masses ending at the study location were used by means of the HYSPLIT back-trajectories analysis. The first one, based on desert dust origin sources, discriminated the optical properties only for sector B (corresponding to western Sahara, northwest Mauritania and southwest Algeria). The particles present marked absorbing properties (low value of single scattering albedo at all wavelengths) during the desert dust events when the air masses were transported from sector A (north Morocco, northwest Algeria). This result may be related to the mixing of desert dust with anthropogenic pollutants from North African industrial areas in addition to the mixing with local anthropogenic aerosol and pollutants transported from European and Mediterranean areas. The second classification method was based on a statistics technique called cluster classification which allows grouping the air masses back trajectories with similar speed and direction of the trajectory. This method showed slight differences in the optical properties between the several transport pathways of air masses. High values of the aerosol optical depth and low mean values of the Angström parameter were associated with longer transport pathways over desert dust sources and slowly moving air masses. Both classification methods showed that the fine mode was mixed with coarse mode, being the fine mode fraction smaller than 55%.

  7. Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multilayer model ADCHAM

    Energy Technology Data Exchange (ETDEWEB)

    Roldin, P.; Eriksson, A. C.; Nordin, E. Z.; Hermansson, E.; Mogensen, Ditte; Rusanen, A.; Boy, Michael; Swietlicki, E.; Svenningsson, Birgitta; Zelenyuk, Alla; Pagels, J.

    2014-08-11

    We have developed the novel Aerosol Dynamics, gas- and particle- phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas phase Master Chemical Mechanism version 3.2, an aerosol dynamics and particle phase chemistry module (which considers acid catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study: 1) the mass transfer limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), 2) the slow and almost particle size independent evaporation of α-pinene secondary organic aerosol (SOA) particles, and 3) the influence of chamber wall effects on the observed SOA formation in smog chambers.

  8. Ice cloud processing of ultra-viscous/glassy aerosol particles leads to enhanced ice nucleation ability

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2012-04-01

    Full Text Available The ice nucleation potential of airborne glassy aqueous aerosol particles has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 247 and 216 K. Four different solutes were used as proxies for oxygenated organic matter found in the atmosphere: raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA, levoglucosan, and a multi-component mixture of raffinose with five dicarboxylic acids and ammonium sulphate. Similar to previous experiments with citric acid aerosols, all particles were found to nucleate ice heterogeneously before reaching the homogeneous freezing threshold provided that the freezing cycles were started well below the respective glass transition temperatures of the compounds; this is discussed in detail in a separate article. In this contribution, we identify a further mechanism by which glassy aerosols can promote ice nucleation below the homogeneous freezing limit. If the glassy aerosol particles are probed in freezing cycles started only a few degrees below their respective glass transition temperatures, they enter the liquid regime of the state diagram upon increasing relative humidity (moisture-induced glass-to-liquid transition before being able to act as heterogeneous ice nuclei. Ice formation then only occurs by homogeneous freezing at elevated supersaturation levels. When ice forms the remaining solution freeze concentrates and re-vitrifies. If these ice cloud processed glassy aerosol particles are then probed in a second freezing cycle at the same temperature, they catalyse ice formation at a supersaturation threshold between 5 and 30% with respect to ice. By analogy with the enhanced ice nucleation ability of insoluble ice nuclei like mineral dusts after they nucleate ice once, we refer to this phenomenon as pre-activation. We propose a number of possible explanations for why glassy aerosols that have re-vitrified in

  9. Fabrication of a pure, uniform electroless silver film using ultrafine silver aerosol particles.

    Science.gov (United States)

    Byeon, Jeong Hoon; Kim, Jang-Woo

    2010-07-20

    To obtain evenly distributed pure Ag particles with a narrow size distribution on a polymer membrane, a novel activation procedure with an environmentally friendly, cost-effective method was utilized as a pretreatment before electroless Ag deposition. The pretreatment was first performed on an untreated membrane surface by collecting ultrafine ambient spark-generated Ag aerosol particles. After annealing, the electroless Ag film was fabricated on the collected aerosol particles in the Ag electroless bath. Experimental characterizations showed that the ultrafine Ag particles were uniformly anchored onto the membrane surface through pretreatment, resulting in a pure Ag film of closely packed particles with a narrow size distribution on the membrane, and the properties were comparable to those of an Ag film on wet Sn-Ag-activated membranes.

  10. The origin of mass elementary particles and fundamental symmetries

    CERN Document Server

    Iliopoulos, John

    2017-01-01

    The discovery of a new elementary particle at the Large Hadron Collider at CERN in 2012 made headlines in world media. Since we already know of a large number of elementary particles, why did this latest discovery generate so much excitement? This small book reveals that this particle provides the key to understanding one of the most extraordinary phenomena which occurred in the early Universe. It introduces the mechanism that made possible, within tiny fractions of a second after the Big Bang, the generation of massive particles. The Origin of Mass is a guided tour of cosmic evolution, from the Big Bang to the elementary particles we study in our accelerators today. The guiding principle of this book is a concept of symmetry which, in a profound and fascinating way, seems to determine the structure of the Universe.

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

    Directory of Open Access Journals (Sweden)

    F. Immler

    2004-09-01

    Full Text Available With a lidar system that was installed in Lindenberg/Germany, we observed in June 2003, an extended aerosol layer at 13 km altitude in the lowermost stratosphere. This layer created an inelastic backscatter signal which we interpret as laser induced fluorescence from aerosol particles. Also, we find evidence for inelastic scattering in a smoke plume from a forest fire that we observed in the troposphere. Fluorescence from ambient aerosol had not yet been considered detectable by lidar. 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 the inelastic backscatter signal 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.

  12. Development and characterization of a single particle laser ablation mass spectrometer (SPLAM for organic aerosol studies

    Directory of Open Access Journals (Sweden)

    F. Gaie-Levrel

    2011-07-01

    Full Text Available A single particle instrument has been developed for real-time analysis of organic aerosols. This instrument, named Single Particle Laser Ablation Mass Spectrometry (SPLAM, samples particles using an aerodynamic lens system for which the theoretical performances were calculated. At the outlet of this system, particle detection and sizing are realized using two continuous diode lasers operating at λ = 403 nm. Polystyrene Latex (PSL, sodium chloride (NaCl and dioctylphtalate (DOP particles were used to characterize and calibrate optical detection of SPLAM. The optical detection limit (DL and detection efficiency (DE were determined using size-selected DOP particles. The DE is ranging from 0.1 to 90 % for 100 and 350 nm DOP particles respectively and the SPLAM instrument is able to detect and size-resolve particles as small as 110–120 nm. Scattered light is detected by two photomultipliers and the detected signals are used to trigger a UV excimer laser (λ = 248 nm used for laser desorption ionization (LDI of individual aerosol particles. The formed ions are analyzed by a 1 m linear time-of-flight mass spectrometer in order to access to the chemical composition of individual particles. The TOF-MS detection limit for gaseous aromatic compounds was determined to be 0.85 attograms. DOP particles were also used to test the overall functioning of the instrument. The analysis of a secondary organic aerosol, formed in a smog chamber by the ozonolysis of indene, is presented as a first scientific application of the instrument. Single particle mass spectra are obtained with a global hit rate of 10 %. They are found to be very different from one particle to another, reflecting chemical differences of the analyzed particles, and most of the detected mass peaks are attributed to oxidized products of indene.

  13. Morphology, Composition, and Mixing State of Individual Aerosol Particles in Northeast China during Wintertime

    Directory of Open Access Journals (Sweden)

    Liang Xu

    2017-02-01

    Full Text Available Northeast China is located in a high latitude area of the world and undergoes a cold season that lasts six months each year. Recently, regional haze episodes with high concentrations of fine particles (PM2.5 have frequently been occurring in Northeast China during the heating period, but little information has been available. Aerosol particles were collected in winter at a site in a suburban county town (T1 and a site in a background rural area (T2. Morphology, size, elemental composition, and mixing state of individual aerosol particles were characterized by transmission electron microscopy (TEM. Aerosol particles were mainly composed of organic matter (OM and S-rich and certain amounts of soot and K-rich. OM represented the most abundant particles, accounting for 60.7% and 53.5% at the T1 and T2 sites, respectively. Abundant spherical OM particles were likely emitted directly from coal-burning stoves. Soot decreased from 16.9% at the T1 site to 4.6% at the T2 site and sulfate particles decrease from 35.9% at the T2 site to 15.7% at the T1 site, suggesting that long-range transport air masses experienced more aging processes and produced more secondary particles. Based on our investigations, we proposed that emissions from coal-burning stoves in most rural areas of the west part of Northeast China can induce regional haze episodes.

  14. Using the Aerosol Single Scattering Albedo and Angstrom Exponent from AERONET to Determine Aerosol Origins and Mixing States over the Indo-Gangetic Plain

    Science.gov (United States)

    Giles, D. M.; Holben, B. N.; Eck, T. F.; Sinyuk, A.; Slutsker, I.; Smirnov, A.; Schafer, J. S.; Dickerson, R. R.; Thompson, A. M.; Tripathi, S. N.; Singh, R. P.; Ghauri, B.

    2012-12-01

    Aerosol mixtures—whether dominated by dust, carbon, sulfates, nitrates, sea salt, or mixtures of them—complicate the retrieval of remotely sensed aerosol properties from satellites and possibly increase the uncertainty of the aerosol radiative impact on climate. Major aerosol source regions in South Asia include the Thar Desert as well as agricultural lands, Himalayan foothills, and large urban centers in and near the Indo-Gangetic Plain (IGP). Over India and Pakistan, seasonal changes in meteorology, including the monsoon (June-September), significantly affect the transport, lifetime, and type of aerosols. Strong monsoonal winds can promote long range transport of dust resulting in mixtures of dust and carbonaceous aerosols, while more stagnant synoptic conditions (e.g., November-January) can prolong the occurrence of urban/industrial pollution, biomass burning smoke, or mixtures of them over the IGP. Aerosol Robotic Network (AERONET) Sun/sky radiometer data are analyzed to show the aerosol optical depth (AOD) seasonality and aerosol dominant mixing states. The Single Scattering Albedo (SSA) and extinction Angstrom exponent (EAE) relationship has been shown to provide sound clustering of dominant aerosol types using long term AERONET site data near known source regions [Giles et al., 2012]. In this study, aerosol type partitioning using the SSA (440 nm) and EAE (440-870 nm) relationship is further developed to quantify the occurrence of Dust, Mixed (e.g., dust and carbonaceous aerosols), Urban/Industrial (U/I) pollution, and Biomass Burning (BB) smoke. Based on EAE thresholds derived from the cluster analysis (for AOD440nm>0.4), preliminary results (2001-2010) for Kanpur, India, show the overall contributions of each dominant particle type (rounded to the nearest 10%): 10% for Dust (EAE≤0.25), 60% for Mixed (0.251.25). In the IGP, BB aerosols may have varying sizes (e.g., corresponding to 1.2mixing with ambient aerosols. Other intensive aerosol properties (e

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

    Directory of Open Access Journals (Sweden)

    E. J. Freney

    2013-09-01

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

  16. A novel tandem differential mobility analyzer with organic vapor treatment of aerosol particles

    Directory of Open Access Journals (Sweden)

    J. Joutsensaari

    2001-01-01

    Full Text Available A novel method to characterize the organic composition of aerosol particles has been developed. The method is based on organic vapor interaction with aerosol particles and it has been named an Organic Tandem Differential Mobility Analyzer (OTDMA. The OTDMA method has been tested for inorganic (sodium chloride and ammonium sulfate and organic (citric acid and adipic acid particles. Growth curves of the particles have been measured in ethanol vapor and as a comparison in water vapor as a function of saturation ratio. Measurements in water vapor show that sodium chloride and ammonium sulfate as well as citric acid particles grow at water saturation ratios (S of 0.8 and above, whereas adipic acid particles do not grow at S S = 0.75 and S = 0.79, respectively. Citric acid particles grow monotonously with increasing saturation ratios already at low saturation ratios and no clear deliquescence point is found. For sodium chloride and ammonium sulfate particles, no growth can be seen in ethanol vapor at saturation ratios below 0.93. In contrast, for adipic acid particles, the deliquescence takes place at around S = 0.95 in the ethanol vapor. The recrystallization of adipic acid takes place at S The results show that the working principles of the OTDMA are operational for single-component aerosols. Furthermore, the results indicate that the OTDMA method may prove useful in determining whether aerosol particles contain organic substances, especially if the OTDMA is operated in parallel with a hygroscopicity TDMA, as the growth of many substances is different in ethanol and water vapors.

  17. Dynamic viscosity mapping of the oxidation of squalene aerosol particles.

    OpenAIRE

    Athanasiadis, Athanasios; Fitzgerald, Clare; Davidson, Nicholas M; Giorio, Chiara; Botchway, Stanley W; Ward, Andrew D.; Kalberer, Markus; Pope, Francis D.; Kuimova, Marina K.

    2016-01-01

    Organic aerosols (OAs) play important roles in multiple atmospheric processes, including climate change, and can impact human health. The physico-chemical properties of OAs are important for all these processes and can evolve through reactions with various atmospheric components, including oxidants. The dynamic nature of these reactions makes it challenging to obtain a true representation of their composition and surface chemistry. Here we investigate the microscopic viscosity of the model OA...

  18. Ultrasensitive detection of inhaled organic aerosol particles by accelerator mass spectrometry.

    Science.gov (United States)

    Parkhomchuk, E V; Gulevich, D G; Taratayko, A I; Baklanov, A M; Selivanova, A V; Trubitsyna, T A; Voronova, I V; Kalinkin, P N; Okunev, A G; Rastigeev, S A; Reznikov, V A; Semeykina, V S; Sashkina, K A; Parkhomchuk, V V

    2016-09-01

    Accelerator mass spectrometry (AMS) was shown to be applicable for studying the penetration of organic aerosols, inhaled by laboratory mice at ultra-low concentration ca. 10(3) cm(-3). We synthesized polystyrene (PS) beads, composed of radiocarbon-labeled styrene, for testing them as model organic aerosols. As a source of radiocarbon we used methyl alcohol with radioactivity. Radiolabeled polystyrene beads were obtained by emulsifier-free emulsion polymerization of synthesized (14)C-styrene initiated by K2S2O8 in aqueous media. Aerosol particles were produced by pneumatic spraying of diluted (14)C-PS latex. Mice inhaled (14)C-PS aerosol consisting of the mix of 10(3) 225-nm particles per 1 cm(3) and 5·10(3) 25-nm particles per 1 cm(3) for 30 min every day during five days. Several millions of 225-nm particles deposited in the lungs and slowly excreted from them during two weeks of postexposure. Penetration of particles matter was also observed for liver, kidneys and brain, but not for a heart.

  19. Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

    Science.gov (United States)

    Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

    2013-07-16

    Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

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

    Science.gov (United States)

    Zuend, A.; Seinfeld, J.

    2011-12-01

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

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

    Science.gov (United States)

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

    2012-12-01

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

  2. Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

    Directory of Open Access Journals (Sweden)

    S. Robertson

    2009-03-01

    Full Text Available MASS (Mesospheric Aerosol Sampling Spectrometer is a multichannel mass spectrometer for charged aerosol particles, which was flown from the Andøya Rocket Range, Norway, through NLC and PMSE on 3 August 2007 and through PMSE on 6 August 2007. The eight-channel analyzers provided for the first time simultaneous measurements of the charge density residing on aerosol particles in four mass ranges, corresponding to ice particles with radii <0.5 nm (including ions, 0.5–1 nm, 1–2 nm, and >3 nm (approximately. Positive and negative particles were recorded on separate channels. Faraday rotation measurements provided electron density and a means of checking charge density measurements made by the spectrometer. Additional complementary measurements were made by rocket-borne dust impact detectors, electric field booms, a photometer and ground-based radar and lidar. The MASS data from the first flight showed negative charge number densities of 1500–3000 cm−3 for particles with radii >3 nm from 83–88 km approximately coincident with PMSE observed by the ALWIN radar and NLC observed by the ALOMAR lidar. For particles in the 1–2 nm range, number densities of positive and negative charge were similar in magnitude (~2000 cm−3 and for smaller particles, 0.5–1 nm in radius, positive charge was dominant. The occurrence of positive charge on the aerosol particles of the smallest size and predominately negative charge on the particles of largest size suggests that nucleation occurs on positive condensation nuclei and is followed by collection of negative charge during subsequent growth to larger size. Faraday rotation measurements show a bite-out in electron density that increases the time for positive aerosol particles to be neutralized and charged negatively. The larger particles (>3 nm are observed throughout the NLC region, 83–88 km, and the smaller particles are observed primarily at the high end of the range, 86–88 km

  3. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    Directory of Open Access Journals (Sweden)

    K. Adachi

    2008-05-01

    Full Text Available Soot particles are major aerosol constituents that result from emissions of burning of fossil fuel and biomass. Because they both absorb sunlight and contribute to cloud formation, they are an influence on climate on local, regional, and global scales. It is therefore important to evaluate their optical and hygroscopic properties and those effects on the radiation budget. Those properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using transmission electron microscopy, we measured ~8000 particles (25 samples with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC and adjacent areas. More than 50% of the particles consist of internally mixed soot, organic matter, and sulfate. Imaging combined with chemical analysis of individual particles show that many are coated, consist of aggregates, or both. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetime. Our results suggest that a mixture of materials from multiple sources such as vehicles, power plants, and biomass burning occurs in individual particles, thereby increasing their complexity. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate than uncoated soot particles. Moreover, soot occurs in more than 60% of all particles in the MC plumes, suggesting its important role in the formation of secondary aerosol particles.

  4. Development and characterization of a single particle laser ablation mass spectrometer (SPLAM for organic aerosol studies

    Directory of Open Access Journals (Sweden)

    F. Gaie-Levrel

    2012-01-01

    Full Text Available A single particle instrument was developed for real-time analysis of organic aerosol. This instrument, named Single Particle Laser Ablation Mass Spectrometry (SPLAM, samples particles using an aerodynamic lens system for which the theoretical performances were calculated. At the outlet of this system, particle detection and sizing are realized by using two continuous diode lasers operating at λ = 403 nm. Polystyrene Latex (PSL, sodium chloride (NaCl and dioctylphtalate (DOP particles were used to characterize and calibrate optical detection of SPLAM. The optical detection limit (DL and detection efficiency (DE were determined using size-selected DOP particles. The DE ranges from 0.1 to 90% for 100 and 350 nm DOP particles respectively and the SPLAM instrument is able to detect and size-resolve particles as small as 110–120 nm. During optical detection, particle scattered light from the two diode lasers, is detected by two photomultipliers and the detected signals are used to trigger UV excimer laser (λ = 248 nm used for one-step laser desorption ionization (LDI of individual aerosol particles. The formed ions are analyzed by a 1 m linear time-of-flight mass spectrometer in order to access to the chemical composition of individual particles. The TOF-MS detection limit for gaseous aromatic compounds was determined to be 0.85 × 10−15 kg (∼4 × 103 molecules. DOP particles were also used to test the overall operation of the instrument. The analysis of a secondary organic aerosol, formed in a smog chamber by the ozonolysis of indene, is presented as a first application of the instrument. Single particle mass spectra were obtained with an effective hit rate of 8%. Some of these mass spectra were found to be very different from one particle to another possibly reflecting chemical differences within the investigated indene SOA particles. Our study shows that an exhaustive statistical analysis, over hundreds of particles

  5. Measurements of airborne influenza virus in aerosol particles from human coughs.

    Directory of Open Access Journals (Sweden)

    William G Lindsley

    Full Text Available Influenza is thought to be communicated from person to person by multiple pathways. However, the relative importance of different routes of influenza transmission is unclear. To better understand the potential for the airborne spread of influenza, we measured the amount and size of aerosol particles containing influenza virus that were produced by coughing. Subjects were recruited from patients presenting at a student health clinic with influenza-like symptoms. Nasopharyngeal swabs were collected from the volunteers and they were asked to cough three times into a spirometer. After each cough, the cough-generated aerosol was collected using a NIOSH two-stage bioaerosol cyclone sampler or an SKC BioSampler. The amount of influenza viral RNA contained in the samplers was analyzed using quantitative real-time reverse-transcription PCR (qPCR targeting the matrix gene M1. For half of the subjects, viral plaque assays were performed on the nasopharyngeal swabs and cough aerosol samples to determine if viable virus was present. Fifty-eight subjects were tested, of whom 47 were positive for influenza virus by qPCR. Influenza viral RNA was detected in coughs from 38 of these subjects (81%. Thirty-five percent of the influenza RNA was contained in particles>4 µm in aerodynamic diameter, while 23% was in particles 1 to 4 µm and 42% in particles<1 µm. Viable influenza virus was detected in the cough aerosols from 2 of 21 subjects with influenza. These results show that coughing by influenza patients emits aerosol particles containing influenza virus and that much of the viral RNA is contained within particles in the respirable size range. The results support the idea that the airborne route may be a pathway for influenza transmission, especially in the immediate vicinity of an influenza patient. Further research is needed on the viability of airborne influenza viruses and the risk of transmission.

  6. The effect of phase partitioning of semivolatile compounds on the measured CCN activity of aerosol particles

    Directory of Open Access Journals (Sweden)

    S. Romakkaniemi

    2013-09-01

    Full Text Available The effect of inorganic semivolatile aerosol compounds on the CCN activity of aerosol particles was studied by using a computational model for a DMT-CCN counter, a cloud parcel model for condensation kinetics and experiments to quantify the modelled results. Concentrations of water vapour and semivolatiles as well as aerosol trajectories in the CCN column were calculated by a computational fluid dynamics model. These trajectories and vapour concentrations were then used as an input for the cloud parcel model to simulate mass transfer kinetics of water and semivolatiles between aerosol particles and the gas phase. Two different questions were studied: (1 how big fraction of semivolatiles is evaporated from particles before activation in the CCN counter? (2 How much the CCN activity can be increased due to condensation of semivolatiles prior to the maximum water supersaturation in the case of high semivolatile concentration in the gas phase? The results show that, to increase the CCN activity of aerosol particles, a very high gas phase concentration (as compared to typical ambient conditions is needed. We used nitric acid as a test compound. A concentration of several ppb or higher is needed for measurable effect. In the case of particle evaporation, we used ammonium nitrate as a test compound and found that it partially evaporates before maximum supersaturation is reached in the CCN counter, thus causing an underestimation of CCN activity. The effect of evaporation is clearly visible in all supersaturations, leading to an underestimation of the critical dry diameter by 10 to 15 nanometres in the case of ammonium nitrate particles in different supersaturations. This result was also confirmed by measurements in supersaturations between 0.1 and 0.7%.

  7. Aerosol number size distributions over a coastal semi urban location: Seasonal changes and ultrafine particle bursts

    Energy Technology Data Exchange (ETDEWEB)

    Babu, S. Suresh, E-mail: s_sureshbabu@vssc.gov.in [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022 (India); Kompalli, Sobhan Kumar [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022 (India); Moorthy, K. Krishna [Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore 560 012 (India)

    2016-09-01

    Number-size distribution is one of the important microphysical properties of atmospheric aerosols that influence aerosol life cycle, aerosol-radiation interaction as well as aerosol-cloud interactions. Making use of one-yearlong measurements of aerosol particle number-size distributions (PNSD) over a broad size spectrum (~ 15–15,000 nm) from a tropical coastal semi-urban location-Trivandrum (Thiruvananthapuram), the size characteristics, their seasonality and response to mesoscale and synoptic scale meteorology are examined. While the accumulation mode contributed mostly to the annual mean concentration, ultrafine particles (having diameter < 100 nm) contributed as much as 45% to the total concentration, and thus constitute a strong reservoir, that would add to the larger particles through size transformation. The size distributions were, in general, bimodal with well-defined modes in the accumulation and coarse regimes, with mode diameters lying in the range 141 to 167 nm and 1150 to 1760 nm respectively, in different seasons. Despite the contribution of the coarse sized particles to the total number concentration being meager, they contributed significantly to the surface area and volume, especially during transport of marine air mass highlighting the role of synoptic air mass changes. Significant diurnal variation occurred in the number concentrations, geometric mean diameters, which is mostly attributed to the dynamics of the local coastal atmospheric boundary layer and the effect of mesoscale land/sea breeze circulation. Bursts of ultrafine particles (UFP) occurred quite frequently, apparently during periods of land-sea breeze transitions, caused by the strong mixing of precursor-rich urban air mass with the cleaner marine air mass; the resulting turbulence along with boundary layer dynamics aiding the nucleation. These ex-situ particles were observed at the surface due to the transport associated with boundary layer dynamics. The particle growth rates from

  8. Individual particle morphology, coatings, and impurities of black carbon aerosols in Antarctic ice and tropical rainfall

    Science.gov (United States)

    Ellis, Aja; Edwards, Ross; Saunders, Martin; Chakrabarty, Rajan K.; Subramanian, R.; Timms, Nicholas E.; Riessen, Arie; Smith, Andrew M.; Lambrinidis, Dionisia; Nunes, Laurie J.; Vallelonga, Paul; Goodwin, Ian D.; Moy, Andrew D.; Curran, Mark A. J.; Ommen, Tas D.

    2016-11-01

    Black carbon (BC) aerosols are a large source of climate warming, impact atmospheric chemistry, and are implicated in large-scale changes in atmospheric circulation. Inventories of BC emissions suggest significant changes in the global BC aerosol distribution due to human activity. However, little is known regarding BC's atmospheric distribution or aged particle characteristics before the twentieth century. Here we investigate the prevalence and structural properties of BC particles in Antarctic ice cores from 1759, 1838, and 1930 Common Era (C.E.) using transmission electron microscopy and energy-dispersive X-ray spectroscopy. The study revealed an unexpected diversity in particle morphology, insoluble coatings, and association with metals. In addition to conventionally occurring BC aggregates, we observed single BC monomers, complex aggregates with internally, and externally mixed metal and mineral impurities, tar balls, and organonitrogen coatings. The results of the study show BC particles in the remote Antarctic atmosphere exhibit complexity that is unaccounted for in atmospheric models of BC.

  9. Simulating Deposition of Aerosol Particles on Single Fiber Surface

    Institute of Scientific and Technical Information of China (English)

    FU Hai-ming; ZHU Hui

    2009-01-01

    The stochastic simulation method, based on the concept of control window and the numerical solution of the Langevin equation, is applied to solve the deposition problem of particles from the flowing suspensions onto a fiber collector. Using the Kuwabara model to characterize the flow field, the effects of Stokes number, interception parameter, packing density, particle size distribution on the collection efficiency, and the deposition morphology of particles onto a collector areexamined. The morphology of deposit obtained in the simulated results agrees well with experimental observations. The estimation of the initial collection efficiency through the simulations considers that the deposited particles are in good agreement with published experimental data. In addition, the collection efficiency of particles increases in a wider particle size distribution region.

  10. Adsorption of NO{sub 2} on carbon aerosols particles at the low ppb-level

    Energy Technology Data Exchange (ETDEWEB)

    Kalberer, M.; Ammann, M.; Baltensperger, U.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    The adsorption of NO{sub 2} at the low ppb-level (3-40 ppb) on carbon aerosol particles was investigated. A sticking coefficient of about 2.10{sup -4} was found, similar to that in previous studies using radioactively labeled {sup 13}NO{sub 2}. (author) 2 figs., 2 refs.

  11. MISR Dark Water aerosol retrievals: operational algorithm sensitivity to particle non-sphericity

    Directory of Open Access Journals (Sweden)

    O. V. Kalashnikova

    2013-02-01

    Full Text Available The aim of this study is to theoretically investigate the sensitivity of the Multi-angle Imaging SpectroRadiometer (MISR operational (Version 22 Dark Water retrieval algorithm to aerosol non-sphericity over the global oceans under actual observing conditions, accounting for current algorithm assumptions. Non-spherical (dust aerosol models, which were introduced in Version 16 of the MISR aerosol product, improved the quality and coverage of retrievals in dusty regions. Due to the sensitivity of the retrieval to the presence of non-spherical aerosols, the MISR aerosol product has been successfully used to track the location and evolution of mineral dust plumes from the Sahara across the Atlantic, for example. However, the MISR global non-spherical aerosol optical depth (AOD fraction product has been found to have several climatological artifacts superimposed on valid detections of mineral dust, including high non-spherical fraction in the Southern Ocean and seasonally variable bands of high non-sphericity. In this paper we introduce a formal approach to examine the ability of the operational MISR Dark Water algorithm to distinguish among various spherical and non-spherical particles as a function of the variable MISR viewing geometry. We demonstrate that under the criteria currently implemented: (1 Dark Water retrieval sensitivity to particle non-sphericity decreases for AOD below about 0.1 primarily due to an unnecessarily large lower bound imposed on the uncertainty in MISR observations at low light levels, and improves when this lower bound is removed; (2 Dark Water retrievals are able to distinguish between the spherical and non-spherical particles currently used for all MISR viewing geometries when the AOD exceeds 0.1; (3 the sensitivity of the MISR retrievals to aerosol non-sphericity varies in a complex way that depends on the sampling of the scattering phase function and the contribution from multiple scattering; and (4 non

  12. MISR Dark Water aerosol retrievals: operational algorithm sensitivity to particle non-sphericity

    Directory of Open Access Journals (Sweden)

    O. V. Kalashnikova

    2013-08-01

    Full Text Available The aim of this study is to theoretically investigate the sensitivity of the Multi-angle Imaging SpectroRadiometer (MISR operational (version 22 Dark Water retrieval algorithm to aerosol non-sphericity over the global oceans under actual observing conditions, accounting for current algorithm assumptions. Non-spherical (dust aerosol models, which were introduced in version 16 of the MISR aerosol product, improved the quality and coverage of retrievals in dusty regions. Due to the sensitivity of the retrieval to the presence of non-spherical aerosols, the MISR aerosol product has been successfully used to track the location and evolution of mineral dust plumes from the Sahara across the Atlantic, for example. However, the MISR global non-spherical aerosol optical depth (AOD fraction product has been found to have several climatological artifacts superimposed on valid detections of mineral dust, including high non-spherical fraction in the Southern Ocean and seasonally variable bands of high non-sphericity. In this paper we introduce a formal approach to examine the ability of the operational MISR Dark Water algorithm to distinguish among various spherical and non-spherical particles as a function of the variable MISR viewing geometry. We demonstrate the following under the criteria currently implemented: (1 Dark Water retrieval sensitivity to particle non-sphericity decreases for AOD below about 0.1 primarily due to an unnecessarily large lower bound imposed on the uncertainty in MISR observations at low light levels, and improves when this lower bound is removed; (2 Dark Water retrievals are able to distinguish between the spherical and non-spherical particles currently used for all MISR viewing geometries when the AOD exceeds 0.1; (3 the sensitivity of the MISR retrievals to aerosol non-sphericity varies in a complex way that depends on the sampling of the scattering phase function and the contribution from multiple scattering; and (4 non

  13. A Novel Aerosol Method for the Production of Hydrogel Particles

    Directory of Open Access Journals (Sweden)

    Diana Guzman-Villanueva

    2011-01-01

    Full Text Available A novel method of generating hydrogel particles for various applications including drug delivery purposes was developed. This method is based on the production of hydrogel particles from sprayed polymeric nano/microdroplets obtained by a nebulization process that is immediately followed by gelation in a crosslinking fluid. In this study, particle synthesis parameters such as type of nebulizer, type of crosslinker, air pressure, and polymer concentration were investigated for their impact on the mean particle size, swelling behavior, and morphology of the developed particles. Spherical alginate-based hydrogel particles with a mean particle size in the range from 842 to 886 nm were obtained. Using statistical analysis of the factorial design of experiment it was found that the main factors influencing the size and swelling values of the particles are the alginate concentration and the air pressure. Thus, it was demonstrated that the method described in the current study is promising for the generation of hydrogel particles and it constitutes a relatively simple and low-cost system.

  14. Ice Formation by Sulfate and Sulfuric Acid Aerosol Particles under Upper-Tropospheric Conditions.

    Science.gov (United States)

    Chen, Yalei; Demott, Paul J.; Kreidenweis, Sonia M.; Rogers, David C.; Eli Sherman, D.

    2000-11-01

    Ice formation in ammoniated sulfate and sulfuric acid aerosol particles under upper-tropospheric conditions was studied using a continuous flow thermal diffusion chamber. This technique allowed for particle exposure to controlled temperatures and relative humidities for known residence times. The phase states of (NH4)2SO4 and NH4HSO4 particles were found to have important impacts on their ice formation capabilities. Dry (NH4)2SO4 particles nucleated ice only at high relative humidity (RH 94%) with respect to water at temperatures between 40° and 60°C. This result suggested either an impedance or finite time dependence to deliquescence and subsequent homogeneous freezing nucleation. Ammonium sulfate particles that entered the diffusion chamber in a liquid state froze homogeneously at relative humidities that were 10% lower than where ice nucleated on initially dry particles. Likewise, crystalline or partially crystallized (as letovicite) NH4HSO4 particles required higher relative humidities for ice nucleation than did initially liquid bisulfate particles. Liquid particles of size 0.2 m composed of either ammonium sulfate or bisulfate froze at lower relative humidity at upper-tropospheric temperatures than did 0.05-m sulfuric acid aerosol particles. Comparison of calculated homogeneous freezing point depressions suggest that size effects on freezing may be more important than the degree of ammoniation of the sulfate compound.

  15. Online Aerosol Mass Spectrometry of Single Micrometer-Sized Particles Containing Poly(ethylene glycol)

    Energy Technology Data Exchange (ETDEWEB)

    Bogan, M J; Patton, E; Srivastava, A; Martin, S; Fergenson, D; Steele, P; Tobias, H; Gard, E; Frank, M

    2006-10-25

    Analysis of poly(ethylene glycol)(PEG)-containing particles by online single particle aerosol mass spectrometers equipped with laser desorption ionization (LDI) is reported. We demonstrate that PEG-containing particles are useful in the development of aerosol mass spectrometers because of their ease of preparation, low cost, and inherently recognizable mass spectra. Solutions containing millimolar quantities of PEGs were nebulized and, after drying, the resultant micrometer-sized PEG containing particles were sampled. LDI (266 nm) of particles containing NaCl and PEG molecules of average molecular weight <500 generated mass spectra reminiscent of mass spectra of PEG collected by other MS schemes including the characteristic distribution of positive ions (Na{sup +} adducts) separated by the 44 Da of the ethylene oxide units separating each degree of polymerization. PEGs of average molecular weight >500 were detected from particles that also contained t the tripeptide tyrosine-tyrosine-tyrosine or 2,5-dihydroxybenzoic acid, which were added to nebulized solutions to act as matrices to assist LDI using pulsed 266 nm and 355 nm lasers, respectively. Experiments were performed on two aerosol mass spectrometers, one reflectron and one linear, that each utilize two time-of-flight mass analyzers to detect positive and negative ions created from a single particle. PEG-containing particles are currently being employed in the optimization of our bioaerosol mass spectrometers for the application of measurements of complex biological samples, including human effluents, and we recommend that the same strategies will be of great utility to the development of any online aerosol LDI mass spectrometer platform.

  16. Interaction of aerosol particles composed of protein and saltswith water vapor: hygroscopic growth and microstructural rearrangement

    OpenAIRE

    Mikhailov, E.; Vlasenko, S.; Niessner, R.; U. Pöschl

    2004-01-01

    The interaction of aerosol particles composed of the protein bovine serum albumin (BSA) and the inorganic salts sodium chloride and ammonium nitrate with water vapor has been investigated by hygroscopicity tandem differential mobility analyzer (H-TDMA) experiments complemented by transmission electron microscopy (TEM) and Köhler theory calculations (100-300nm particle size range, 298K, 960hPa). BSA was chosen as a well-defined model substance for proteins and other macromolecular compoun...

  17. Physical aerosol properties and their relation to air mass origin at Monte Cimone (Italy during the first MINATROC campaign

    Directory of Open Access Journals (Sweden)

    R. Van Dingenen

    2005-01-01

    Full Text Available Aerosol physical properties were measured at the Monte Cimone Observatory (Italy from 1 June till 6 July 2000. The measurement site is located in the transition zone between the continental boundary layer and the free troposphere (FT, at the border between the Mediterranean area and Central Europe, and is exposed to a variety of air masses. Sub-μm number size distributions, aerosol hygroscopicity near 90% RH, refractory size distribution at 270°C and equivalent black carbon mass were continuously measured. Number size distributions and hygroscopic properties indicate that the site is exposed to aged continental air masses, however during daytime it is also affected by upslope winds. The mixing of this transported polluted boundary layer air masses with relatively clean FT air leads to frequent nucleation events around local noon. Night-time size distributions, including fine and coarse fractions for each air mass episode, have been parameterized by a 3-modal lognormal distribution. Number and volume concentrations in the sub-μm modes are strongly affected by the air mass origin, with highest levels in NW-European air masses, versus very clean, free tropospheric air coming from the N-European sector. During a brief but distinct dust episode, the coarse mode is clearly enhanced. The observed hygroscopic behavior of the aerosol is consistent with the chemical composition described by Putaud et al. (2004, but no closure between known chemical composition and measured hygroscopicity could be made because the hygroscopic properties of the water-soluble organic matter (WSOM are not known. The data suggest that WSOM is slightly-to-moderately hygroscopic (hygroscopic growth factor GF at 90% relative humidity between 1.05 and 1.51, and that this property may well depend on the air mass origin and history. External mixing of aerosol particles is observed in all air masses through the occurrence of two hygroscopicity modes (average GF of 1.22 and 1

  18. Interaction of aerosol particles with a standing wave optical field

    Science.gov (United States)

    Curry, John J.

    2016-09-01

    Trajectories of spherical dielectric particles carried across an optical standing wave by a flowing medium are investigated. Trajectories are determined by a three-dimensional Monte Carlo calculation that includes drag forces, Brownian motion, and optical gradient forces. We analyze the case of polystyrene particles with radii of order 100 nm carried across a Gaussian-mode standing wave by slowly flowing air. Particles are injected into the flowing air from a small source area such as the end of a capillary tube. Different sizes are dispersed continuously in space on the opposite side of the standing wave, demonstrating a practical way to sort particles. Certain discrete values of particle size show no interaction with the optical field, independent of intensity. These particles can be sorted with exceptionally high resolution. For example, particles with radii of 275 nm can be sorted with 1 nm resolution. This sorting scheme has the advantages of accommodating a high throughput, producing a continuous stream of continuously dispersed particles, and exhibiting excellent size resolution. The Monte Carlo results are in agreement with those obtained by a much simpler, and faster, fluid calculation based on effective velocities and effective diffusion coefficients, both obtained by averaging trajectories over multiple fringes of the optical field.

  19. Resonant fiber based aerosol particle sensor and method

    DEFF Research Database (Denmark)

    2013-01-01

    in resonance frequency due to depositing of nano-sized particles is correlated with the mass deposited on the elongate member and the vibration frequency of the elongate member is determined by a detector. The read-out from the detector is transformed into a mass deposited on the elongate member. Particles...

  20. Mass Concentration and Mineralogical Characteristics Aerosol Particles Collected at Dunhuang During ACE-Asia

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

  1. Particle growth by acid-catalyzed heterogeneous reactions of organic carbonyls on preexisting aerosols.

    Science.gov (United States)

    Jang, Myoseon; Carroll, Brian; Chandramouli, Bharadwaj; Kamens, Richard M

    2003-09-01

    Aerosol growth by the heterogeneous reactions of different aliphatic and alpha,beta-unsaturated carbonyls in the presence/absence of acidified seed aerosols was studied in a 2 m long flow reactor (2.5 cm i.d.) and a 0.5-m3 Teflon film bag under darkness. For the flow reactor experiments, 2,4-hexadienal, 5-methyl-3-hexen-2-one, 2-cyclohexenone, 3-methyl-2-cyclopentenone, 3-methyl-2-cyclohexenone, and octanal were studied. The carbonyls were selected based on their reactivity for acid-catalyzed reactions, their proton affinity, and their similarity to the ring-opening products from the atmospheric oxidation of aromatics. To facilitate acid-catalyzed heterogeneous hemiacetal/acetal formation, glycerol was injected along with inorganic seed aerosols into the flow reactor system. Carbonyl heterogeneous reactions were accelerated in the presence of acid catalysts (H2SO4), leading to higher aerosol yields than in their absence. Aldehydes were more reactive than ketones for acid-catalyzed reactions. The conjugated functionality also resulted in higher organic aerosol yieldsthan saturated aliphatic carbonyls because conjugation with the olefinic bond increases the basicity of the carbonyl leading to increased stability of the protonated carbonyl. Aerosol population was measured from a series of sampling ports along the length of the flow reactor using a scanning mobility particle sizer. Fourier transform infrared spectrometry of either an impacted liquid aerosol layer or direct reaction of carbonyls as a thin liquid layer on a zinc selenide FTIR disk was employed to demonstrate the direct transformation of chemical functional groups via the acid-catalyzed reactions. These results strongly indicate that atmospheric multifunctional organic carbonyls, which are created by atmospheric photooxidation reactions, can contribute significantly to secondary organic aerosol formation through acid-catalyzed heterogeneous reactions. Exploratory studies in 25- and 190-m3 outdoor chambers

  2. Influence of physical properties and chemical composition of sample on formation of aerosol particles generated by nanosecond laser ablation at 213 nm

    Energy Technology Data Exchange (ETDEWEB)

    Hola, Marketa, E-mail: mhola@sci.muni.c [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Konecna, Veronika [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Mikuska, Pavel [Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic v.v.i., Veveri 97, 602 00 Brno (Czech Republic); Kaiser, Jozef [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); Kanicky, Viktor [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)

    2010-01-15

    The influence of sample properties and composition on the size and concentration of aerosol particles generated by nanosecond Nd:YAG laser ablation at 213 nm was investigated for three sets of different materials, each containing five specimens with a similar matrix (Co-cemented carbides with a variable content of W and Co, steel samples with minor differences in elemental content and silica glasses with various colors). The concentration of ablated particles (particle number concentration, PNC) was measured in two size ranges (10-250 nm and 0.25-17 mum) using an optical aerosol spectrometer. The shapes and volumes of the ablation craters were obtained by Scanning Electron Microscopy (SEM) and by an optical profilometer, respectively. Additionally, the structure of the laser-generated particles was studied after their collection on a filter using SEM. The results of particle concentration measurements showed a significant dominance of particles smaller than 250 nm in comparison with larger particles, irrespective of the kind of material. Even if the number of particles larger than 0.25 mum is negligible (up to 0.1%), the volume of large particles that left the ablation cell can reach 50% of the whole particle volume depending on the material. Study of the ablation craters and the laser-generated particles showed a various number of particles produced by different ablation mechanisms (particle splashing or condensation), but the similar character of released particles for all materials was observed by SEM after particle collection on the membrane filter. The created aerosol always consisted of two main structures - spherical particles with diameters from tenths to units of micrometers originally ejected from the molten surface layer and mum-sized 'fibres' composed of primary agglomerates with diameters in the range between tens and hundreds of nanometers. The shape and structure of ablation craters were in good agreement with particle concentration

  3. Impact of wild forest fires in Eastern Europe on aerosol composition and particle optical properties

    Directory of Open Access Journals (Sweden)

    Tymon Zielinski

    2016-01-01

    Full Text Available In this paper the authors discuss the changes of aerosol optical depth (AOD in the region of eastern Europe and the Baltic Sea due to wild fire episodes which occurred in the area of Belarus and Ukraine in 2002. The authors discuss how the biomass burning aerosols were advected over the Baltic area and changed the composition of aerosol ensemble for a period of several summer weeks. The air pressure situation and slow wind speeds also facilitated the development of such conditions. As a consequence very high AOD levels were recorded, by an order of 3–4 higher versus normal conditions and they significantly increased the annual averages. On particular days of August 2002 the AOD values reached a level of over 0.7. On these days fine particles fully dominated the entire ensemble of aerosol particles. They were either sulfates or smoke particles. Such situation was unique over a period of many years and it had its serious consequences for the region and especially for the Baltic Sea.

  4. Aerosol vertical distribution, new particle formation, and jet aircraft particle emissions in the free troposhere and tropopause region; Vertikalverteilung und Neubildungsprozesse des Aerosols und partikelfoermige Flugzeugemissionen in der freien Troposphaere und Tropopausenregion

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F.P.

    2000-07-01

    A contribution to the understanding of natural and anthropogenously induced particle formation as well as aerosol physical transformation processes within the free troposphere (FT) is introduced. Documentation and interpretation of empirical data relevant with respect to possible climatologic impact of anthropogenous aerosol emissions into the atmosphere is presented. The first section describes new technique for high spatial resolution measurements of ultrafine aerosol particles by condensation nucleus counters (CNCs), a necessary prerequisite for the observation of natural particle formation and jet aircraft emissions. The second section illustrates vertical distribution and variability ranges of the aerosol in the FT and the tropopause region (TP). Typical microphysical states of the atmospheric aerosol within the Northern Hemisphere are documented by means of systematic measurements during more than 60 flight missions. Simple mathematical parameterizations of the aerosol vertical distribution and aerosol size distributions are developed. Important aerosol sources within the FT are localized and possible aerosol formation processes are discussed. The third section is focussed on jet-engine particle emissions within the FT and TP. A unique inflight experiment for detection of extremely high concentrations (>10{sup 6} cm{sup -3}) of extremely small (donw to <3 nm) aerosols inside the exhaust plumes of several jet aircraft is described. Particle emission indices and emission-controlling parameters are deduced. Most important topic is the impact of fuel sulfur content of kerosine on number, size and chemical composition of jet particle emissions. Generalized results are parameterized in form of lognormal aerosol particle size distributions. (orig.) [German] Ein Beitrag zum Verstaendnis natuerlicher und anthropogen induzierter Aerosolneubildung sowie physikalischer Aerosolumwandlung in der freien Troposphaere wird vorgestellt. Empirisch gewonnenes Datenmaterial wird

  5. 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

  6. Characterization of new particle and secondary aerosol formation during summertime in Beijing, China

    Science.gov (United States)

    Zhang, Y. M.; Zhang, X. Y.; Sun, J. Y.; Lin, W. L.; Gong, S. L.; Shen, X. J.; Yang, S.

    2011-07-01

    Size-resolved aerosol number and mass concentrations and the mixing ratios of O3 and various trace gases were continuously measured at an urban station before and during the Beijing Olympic and Paralympic Games (5 June to 22 September, 2008). 23 new particle formation (NPF) events were identified; these usually were associated with changes in wind direction and/or rising concentrations of gas-phase precursors or after precipitation events. Most of the NPF events started in the morning and continued to noon as particles in the nucleation mode grew into the Aitken mode. From noon to midnight, the aerosols grew into the accumulation mode through condensation and coagulation. Ozone showed a gradual rise starting around 10:00 local time, reached its peak around 15:00 and then declined as the organics increased. The dominant new particle species were organics (40-75% of PM1) and sulphate; nitrate and ammonium were more minor contributors.

  7. Characterization of new particle and secondary aerosol formation during summertime in Beijing, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y. M. (Key Laboratory for Atmospheric Chemistry, Centre for Atmosphere Watch and Services, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing (China); Graduate Univ. of Chinese Academy of Sciences, Beijing (China)); Zhang, X. Y.; Sun, J. Y.; Lin, W. L.; Shen, X. J. (Key Laboratory for Atmospheric Chemistry, Centre for Atmosphere Watch and Services, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing (China)), e-mail: xiaoye@cams.cma.gov.cn; Gong, S. L. (Air Quality Research Div., Science and Technology Branch, Environment Canada, Toronto (Canada)); Yang, S. (State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Inst. of Atmospheric Physics, CAS, Beijing (China))

    2011-07-15

    Size-resolved aerosol number and mass concentrations and the mixing ratios of O{sub 3} and various trace gases were continuously measured at an urban station before and during the Beijing Olympic and Paralympic Games (5 June to 22 September, 2008). 23 new particle formation (NPF) events were identified; these usually were associated with changes in wind direction and/or rising concentrations of gas-phase precursors or after precipitation events. Most of the NPF events started in the morning and continued to noon as particles in the nucleation mode grew into the Aitken mode. From noon to midnight, the aerosols grew into the accumulation mode through condensation and coagulation. Ozone showed a gradual rise starting around 10:00 local time, reached its peak around 15:00 and then declined as the organics increased. The dominant new particle species were organics (40-75% of PM{sub 1}) and sulphate; nitrate and ammonium were more minor contributors

  8. Kinetic analysis of competition between aerosol particle removal and generation by ionization air purifiers.

    Science.gov (United States)

    Alshawa, Ahmad; Russell, Ashley R; Nizkorodov, Sergey A

    2007-04-01

    Ionization air purifiers are increasingly used to remove aerosol particles from indoor air. However, certain ionization air purifiers also emit ozone. Reactions between the emitted ozone and unsaturated volatile organic compounds (VOC) commonly found in indoor air produce additional respirable aerosol particles in the ultrafine (air purifiers under conditions of a typical residential building. This model predicts that certain widely used ionization air purifiers may actually increase the mass concentration of fine and ultrafine particulates in the presence of common unsaturated VOC, such as limonene contained in many household cleaning products. This prediction is supported by an explicit observation of ultrafine particle nucleation events caused by the addition of D-limonene to a ventilated office room equipped with a common ionization air purifier.

  9. In-situ observations of interstitial aerosol particles and cloud residues found in contrails

    Energy Technology Data Exchange (ETDEWEB)

    Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    In spring 1994 a series of flights were conducted in cirrus clouds and contrails over southern Germany. One of the aims of this campaign was to study the phase partitioning of aerosols and water in these clouds. To achieve this separation of particles two complementary sampling probes were mounted on the research aircraft Falcon. These are the Counterflow Virtual Impactor (CVI) or super-micrometer inlet, and the interstitial inlet or submicrometer inlet. The CVI is a device that inertially separates cloud elements larger than a certain aerodynamic size from the surrounding atmosphere into a warm, dry and particle free air. Assuming that each cloud element leaves behind only one residue particle, these measurements yield an equivalent number concentration for cloud particles having an aerodynamic diameter larger than the lower cut size of the CVI. The size distribution of the sampled aerosol and residual particles between 0.1 to 3.5 {mu}m diameter was measured by a PMS PCASP (Passive Cavity Aerosol Spectrometer) working alternatively on both inlets. The gas-phase water vapor content was measured by a cryogenic frost point mirror. (R.P.) 4 refs.

  10. Isotope source apportionment of carbonaceous aerosol as a function of particle size and thermal refractiveness

    Science.gov (United States)

    Masalaite, Agne; Holzinger, Rupert; Remeikis, Vidmantas; Röckmann, Thomas; Dusek, Ulrike

    2016-04-01

    The stable carbon isotopes can be used to get information about sources and processing of carbonaceous aerosol. We will present results from source apportionment of carbonaceous aerosol as a function of particle size thermal refractiveness. Separate source apportionment for particles smaller than 200 nm and for different carbon volatility classes are rarely reported and give new insights into aerosol sources in the urban environment. Stable carbon isotope ratios were measured for the organic carbon (OC) fraction and total carbon (TC) of MOUDI impactor samples that were collected on a coastal site (Lithuania) during the winter 2012 and in the city of Vilnius (Lithuania) during the winter of 2009. The 11 impactor stages spanned a size range from 0.056 to 18 μm, but only the 6 stages in the submicron range were analysed. The δ13C values of bulk total carbon (δ13CTC) were determined with an elemental analyser (Flash EA 1112) coupled with an isotope ratio mass spectrometer (Thermo Finnigan Delta Plus Advantage) (EA - IRMS). Meanwhile δ13COC was measured using thermal-desorption isotope ratio mass spectrometry (IRMS) system. This allows a rough separation of the more volatile OC fraction (desorbed in the oven of IRMS up to 250 0C) from the more refractory fraction (desorbed up to 400 0C). In this study we investigated the composition of organic aerosol desorbed from filter samples at different temperatures using the thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) technique. During winter-time in Lithuania we expect photochemistry and biogenic emissions to be of minor importance. The main sources of aerosol carbon should be fossil fuel and biomass combustion. In both sites, the coastal and the urban site, δ13C measurements give a clear indication that the source contributions differ for small and large particles. Small particles grants Nr. 820.01.001, and 834.08.002).

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

    Science.gov (United States)

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

    2014-04-25

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

  12. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2007-05-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were carried out in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area – 2006 campaign (MCMA-2006 between 7–27 March, 2006. Biomass and organic carbon (OC particle types were found to dominate the accumulation mode both day and night. The concentrations of both organic carbon and biomass particles were roughly equal early in the morning, but biomass became the largest contributor to the accumulation mode mass from the late morning until early evening. The diurnal pattern can be attributed to aging and/or a change in meteorology. Fresh elemental carbon (EC particles were observed during rush hour. The majority of the EC particles were mixed with nitrate, sulfate, organic carbon and potassium. Submicron particles from industrial sources in the northeast were composed of an internal mixture of Pb, Zn, EC and Cl and peaked early in the morning. A unique nitrogen-containing organic (NOC particle type was observed, and is hypothesized to be from industrial emissions based on the temporal profile and back trajectory analysis. This study provides unique insights into the real-time changes in single particle mixing state as a function of size and time for aerosols in Mexico City. These new findings indicate that biomass burning and industrial operations make significant contributions to particles in Mexico City. These sources have received relatively little attention in previous intensive field campaigns.

  13. Real time analysis of lead-containing atmospheric particles in Beijing during springtime by single particle aerosol mass spectrometry.

    Science.gov (United States)

    Ma, Li; Li, Mei; Huang, Zhengxu; Li, Lei; Gao, Wei; Nian, Huiqing; Zou, Lilin; Fu, Zhong; Gao, Jian; Chai, Fahe; Zhou, Zhen

    2016-07-01

    Using a single particle aerosol mass spectrometer (SPAMS), the chemical composition and size distributions of lead (Pb)-containing particles with diameter from 0.1 μm to 2.0 μm in Beijing were analyzed in the spring of 2011 during clear, hazy, and dusty days. Based on mass spectral features of particles, cluster analysis was applied to Pb-containing particles, and six major classes were acquired consisting of K-rich, carboneous, Fe-rich, dust, Pb-rich, and Cl-rich particles. Pb-containing particles accounted for 4.2-5.3%, 21.8-22.7%, and 3.2% of total particle number during clear, hazy and dusty days, respectively. K-rich particles are a major contribution to Pb-containing particles, varying from 30.8% to 82.1% of total number of Pb-containing particles, lowest during dusty days and highest during hazy days. The results reflect that the chemical composition and amount of Pb-containing particles has been affected by meteorological conditions as well as the emissions of natural and anthropogenic sources. K-rich particles and carbonaceous particles could be mainly assigned to the emissions of coal combustion. Other classes of Pb-containing particles may be associated with metallurgical processes, coal combustion, dust, and waste incineration etc. In addition, Pb-containing particles during dusty days were first time studied by SPAMS. This method could provide a powerful tool for monitoring and controlling of Pb pollution in real time.

  14. Impacts of new particle formation on aerosol cloud condensation nuclei (CCN activity in Shanghai: case study

    Directory of Open Access Journals (Sweden)

    C. Leng

    2014-07-01

    Full Text Available New particle formation (NPF events and their impacts on cloud condensation nuclei (CCN were investigated using continuous measurements collected in urban Shanghai from 1 to 30 April 2012. During the campaign, NPF occurred in 8 out of the 30 days and enhanced CCN number concentration (NCCN by a actor of 1.2–1.8, depending on supersaturation (SS. The NPF event on 3 April 2012 was chosen as an example to investigate the NPF influence on CCN activity. In this NPF event, secondary aerosols were produced continuously and increased PM2.5 mass concentration at a~rate of 4.33 μg cm−3 h−1, and the growth rate (GR and formation rate (FR were on average 5 nm h−1 and 0.36 cm−3 s−1, respectively. The newly formed particles grew quickly from nucleation mode (10–20 nm into CCN size range. NCCN increased rapidly at SS of 0.4–1.0% but weakly at SS of 0.2%. Correspondingly, aerosol CCN activities (fractions of activated aerosol particles in total aerosols, NCCN / NCN were significantly enhanced from 0.24–0.60 to 0.30–0.91 at SS of 0.2–1.0% due to the NPF. On the basis of the κ-Köhler theory, aerosol size distributions and chemical composition measured simultaneously were used to predict NCCN. There was a good agreement between the predicted and measured NCCN (R2 = 0.96, Npredicted / Nmeasured = 1.04. This study reveals that NPF exerts large impacts on aerosol particle abundance and size spectra, thus significantly promotes NCCN and aerosol CCN activity in this urban environment. The GR of NPF is the key factor controlling the newly formed particles to become CCN at all SS levels, whereas the FR is an effective factor only under high SS (e.g. 1.0% conditions.

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

    Science.gov (United States)

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

    2009-04-01

    Assessing the impact of atmospheric aerosol particles on the environment requires adequate representation of appropriate key processes within large scale models. In the absence of primary particulate material, interactions between the atmospheric gaseous components and particles means that the chemical nature of the particles is largely determined by the availability of condensable gaseous material, such as sulphuric and nitric acids, and by the ambient environmental conditions. Gas to particle mass transfer of semi-volatile components,driven by a difference in equilibrium and actual partial pressures above an aerosol particle, is an important factor in determining the evolving chemical composition of the particle and is necessary for predicting aerosol loading and composition. The design of an appropriate framework required for parameterizations of key variables is challenging. These thermodynamic frameworks are often numerically very complex, resulting in significant computational expense. Three dimensional chemical and aerosol transport models demand that computational expense be kept at a minimum,resulting in a trade-off between accuracy and efficiency. To calculate the equilibrium vapour pressure above a solution requires treatment of solution nonideality. This is manifest through activity coefficients of components pertinent to each condensing specie. However, activity coefficients are complex functions of the solution composition. Parameterisation of activity coefficients provides the main focus of this work largely because reducing the numerical complexity whilst retaining a good level of accuracy is very challenging. The approach presented here, the hybrid Partial Derivative Fitted Taylor Expansion (PDFiTE) (Topping et al 2008), builds on previously reported work, with an aim to derive parameters for an accurate and computationally efficient framework through coupling with a complex thermodynamic model. Such a reduction in complexity is important as it is

  16. Biological aerosol particle concentrations and size distributions measured in pristine tropical rainforest air during AMAZE-08

    OpenAIRE

    J. A. Huffman; Sinha, B.; R. M. Garland; A. Snee-Pollmann; Gunthe, S. S.; Artaxo, P.; S. T. Martin; Andreae, M. O.; U. Pöschl

    2012-01-01

    As a part of the AMAZE-08 campaign during the wet season in the rainforest of Central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m&m...

  17. DUAL ORIGIN OF AEROSOLS IN TITAN'S DETACHED HAZE LAYER

    Energy Technology Data Exchange (ETDEWEB)

    Cours, T.; Burgalat, J.; Rannou, P. [Groupe de Spectrometrie Moleculaire et Atmospherique (GSMA), CNRS UMR-6089, Universite de Reims Champagne-Ardenne, 51687 Reims Cedex 2 (France); Rodriguez, S.; Brahic, A. [Laboratoire AIM, Universite Paris 7, CNRS UMR-7158, CEA-Saclay/DSM/IRFU/SAp, 91191 Gif/Yvette (France); West, R. A., E-mail: thibaud.cours@univ-reims.fr [Jet Propulsion Laboratory M/S 169-237, Pasadena, CA 91109 (United States)

    2011-11-10

    We have analyzed scattered light profiles from the Cassini Imaging Science Subsystem, taken at the limb and at several large phase angles. We also used results from an occultation observed by Ultraviolet Imaging Spectrograph in the ultraviolet. We found that particles responsible for the scattering in the detached haze have an effective radius around 0.15 {mu}m and the aerosol size distribution follows a power law (exponent about -4.5). We discuss these results along with microphysical constraints and thermal equilibrium of the detached haze, and we conclude that only a strong interaction with atmospheric dynamics can explain such a structure.

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

    Science.gov (United States)

    Tie, Xuexi; Wu, Dui; Brasseur, Guy

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

  19. Chemical and statistical interpretation of sized aerosol particles collected at an urban site in Thessaloniki, Greece.

    Science.gov (United States)

    Tsitouridou, Roxani; Papazova, Petia; Simeonova, Pavlina; Simeonov, Vasil

    2013-01-01

    The size distribution of aerosol particles (PM0.015-PM18) in relation to their soluble inorganic species and total water soluble organic compounds (WSOC) was investigated at an urban site of Thessaloniki, Northern Greece. The sampling period was from February to July 2007. The determined compounds were compared with mass concentrations of the PM fractions for nano (N: 0.015 pollution were identified and an attempt is made to find patterns of similarity between the different sized aerosols and the seasons of monitoring. It was proven that several major latent factors are responsible for the data structure despite the size of the aerosols - mineral (soil) dust, sea sprays, secondary emissions, combustion sources and industrial impact. The seasonal separation proved to be not very specific.

  20. Early growth dynamical implications for the steerability of stratospheric solar radiation management via sulfur aerosol particles

    Science.gov (United States)

    Benduhn, François; Schallock, Jennifer; Lawrence, Mark G.

    2016-09-01

    Aerosol growth dynamics may have implications for the steerability of stratospheric solar radiation management via sulfur particles. This paper derives a set of critical initial growth conditions that are analyzed as a function of two key parameters: the initial concentration of the injected sulfuric acid and its dilution rate with the surrounding air. Based upon this analysis, early aerosol growth dynamical regimes may be defined and classified in terms of their likelihood to serve as candidates for the controlled generation of a radiatively effective aerosol. Our results indicate that the regime that fulfills all critical conditions would require that airplane turbines be used to provide sufficient turbulence. The regime's parameter space is narrow and related to steep gradients, thus pointing to potential fine tuning requirements. More research, development, and testing would be required to refine our findings and determine their global-scale implications.

  1. INTEGRAL COLLISION KERNEL FOR THE GROWTH OF AEROSOL PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Hongyong Xie

    2005-01-01

    Integral collision kernel is elucidated using experimental results for titania, silica and alumina nanoparticles synthesized by FCVD process, and titania submicron particles synthesized in a tube furnace reactor. The integral collision kernel was obtained from a particle number balance equation by the integration of collision rates from the kinetic theory of dilute gases for the free-molecule regime, from the Smoluchowski theory for the continuum regime, and by a semi-empirical interpolation for the transition regime between the two limiting regimes. Comparisons have been made on particle size and the integral collision kernel, showing that the predicted integral collision kernel agreed well with the experimental results in Knudsen number range from about 1.5 to 20.

  2. Simulating the evolution of soot mixing state with a particle-resolved aerosol model

    CERN Document Server

    Riemer, N; Zaveri, R A; Easter, R C

    2008-01-01

    The mixing state of soot particles in the atmosphere is of crucial importance for assessing their climatic impact, since it governs their chemical reactivity, cloud condensation nuclei activity and radiative properties. To improve the mixing state representation in models, we present a new approach, the stochastic particle-resolved model PartMC-MOSAIC, which explicitly resolves the composition of individual particles in a given population of different types of aerosol particles. This approach accurately tracks the evolution of the mixing state of particles due to emission, dilution, condensation and coagulation. To make this direct stochastic particle-based method practical, we implemented a new multiscale stochastic coagulation method. With this method we achieved optimal efficiency for applications when the coagulation kernel is highly non-uniform, as is the case for many realistic applications. PartMC-MOSAIC was applied to an idealized urban plume case representative of a large urban area to simulate the e...

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

    Science.gov (United States)

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

    2014-07-01

    Carbon cycling in the Amazon is closely linked to atmospheric processes and climate in the region as a consequence of the strong coupling between the atmosphere and biosphere. This work examines the effects of changes in net radiation due to atmospheric aerosol particles and clouds on the net ecosystem exchange (NEE) of CO2 in the Amazon region. Some of the major environmental factors affecting the photosynthetic activity of plants, such as air temperature and relative humidity, were also examined. An algorithm for clear-sky irradiance was developed and used to determine the relative irradiance, f, which quantifies the percentage of solar radiation absorbed and scattered due to atmospheric aerosol particles and clouds. Aerosol optical depth (AOD) was calculated from irradiances measured with the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor, onboard the Terra and Aqua satellites, and was validated with ground-based AOD measurements from AERONET (Aerosol Robotic Network) sun photometers. Carbon fluxes were measured using eddy covariance technique at the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) flux towers. Two sites were studied: the Jaru Biological Reserve (RBJ), located in Rondonia, and the Cuieiras Biological Reserve at the K34 LBA tower (located in a preserved region in the central Amazon). Analysis was performed continuously from 1999 to 2009 at K34 and from 1999 to 2002 at RBJ, and includes wet, dry and transition seasons. In the Jaru Biological Reserve, a 29% increase in carbon uptake (NEE) was observed when the AOD ranged from 0.10 to 1.5 at 550 nm. In the Cuieiras Biological Reserve, the aerosol effect on NEE was smaller, accounting for an approximate 20% increase in NEE. High aerosol loading (AOD above 3 at 550 nm) or high cloud cover leads to reductions in solar flux and strong decreases in photosynthesis up to the point where NEE approaches zero. The observed increase in NEE is attributed to an enhancement (~50%) in

  4. Physical aerosol properties and their relation to air mass origin at Monte Cimone (Italy during the first MINATROC campaign

    Directory of Open Access Journals (Sweden)

    R. Van Dingenen

    2005-02-01

    Full Text Available Aerosol physical properties were measured at the Monte Cimone Observatory (Italy from 1 June till 6 July 2000. The measurement site is located in the transition zone between continental boundary layer and the free troposphere (FT, at the border between the Mediterranean area and Central Europe, and is exposed to a variety of air masses. Sub-micrometer number size distributions, aerosol hygroscopicity at 90% RH, refractory size distribution at 270°C and black carbon mass were continuously measured. Number size distributions and hygroscopic properties indicate that the site is exposed to aged continental air masses, however during daytime it is also affected by upslope winds. The mixing of this transported polluted boundary layer air masses with relatively clean FT air leads to frequent nucleation events around local noon.

    Night-time size distributions including fine and coarse fractions for each air mass episode have been parameterized by a 3-modal lognormal distribution. Number and volume concentrations in the sub-micrometer modes are strongly affected by the air mass origin, with highest levels in NW-European air masses, versus very clean air in the ''Arctic'' episode. During the dust episode, the coarse mode is clearly enhanced.

    The observed hygroscopic behavior of the aerosol is consistent with the chemical composition described by Putaud et al. (2004a, but no closure could be made because the hygroscopic properties of the water-soluble organic matter is not known. The data suggest that WSOM is slightly-to-moderately hygroscopic, and that this property may well depend on the air mass origin and history.

    Although externally mixing is observed in all air masses, the occurrence of ''less'' hygroscopic particles has mostly such a low occurrence rate that the average growth factor distribution mostly appears as a single mode. This is not the case for the dust episode, where the

  5. Transmission Electron Microscopy Analysis of Submicronic Aerosol Particles Sampled at Jungfraujoch, Switzerland (CLACE-4)

    Science.gov (United States)

    Grobéty, B.; Lorenzo, R.

    2007-05-01

    Submicronic aerosol particles were collected in two sampling campaigns during CLACE-4 and -5 ("the Cloud and Aerosol Characterisation Experiment in the Free Troposphere") at the high alpine research station on top of Jungfraujoch (altitude: 3580 m.a.s.l.). The particles were deposited directly on transmission electron microscopy (TEM) grids placed in a home-made, calibrated thermophoretic sampling device. The samples were taken during periods of clear skies and temperatures below 0°C. Average sampling time was two days. The primary state of the particles was either solid, mixed solid-liquid or completely liquid. EDS spectra of solid particles without visible traces of a liquid coating contain only carbon and oxygen peaks. Mixed solid-fluid particles, however, have either carbon (C), mixed carbon-silicate (CS) or silicate (S) (probably SiO2) nuclei. The condensates remaining after evaporation of the liquid components contain sulfate (sulfur and oxygen peaks in EDS spectra), but no nitrate was found. The fraction > 500 nm is dominated by C and CS particles, the silicate particles have a narrow size distribution around 100 nm and contain, if at all, only faint sulfur peaks in their EDS spectra. The results are qualitatively consistent with analyses of samples collected during the same campaign (Weinbruch et al., 2005), but during mixed cloud events. There seem to be, however a differrence in the amount of particles with sulfate coatings, which is higher for samples taken under clear sky conditions. Weinbruch, S., Ebert, S., Worringen, A., and Brenker (2005), Identification of the ice forming fraction of the atmospheric aerosol in mixed-phase clouds by environmental scanning electron microscopy. Activity report 2005, International Foundation HFSJG.

  6. Hygroscopic behaviour of aerosol particles emitted from biomass fired grate boilers

    Energy Technology Data Exchange (ETDEWEB)

    Rissler, Jenny; Swietlicki, Erik [Lund Univ. (Sweden). Div. of Nuclear Physics; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats [Lund Univ. (Sweden). Div. of Ergonomics and Aerosol Technology; Strand, Michael; Lillieblad, Lena; Sanati, Mehri [Vaexjoe Univ. (Sweden). Bioenergy Technology

    2005-02-01

    This study focuses on the hygroscopic properties of sub-micrometer aerosol particles emitted from two small-scale district heating combustion plants (1 and 1.5 MW) burning two types of biomass fuels (moist forest residue and pellets). The hygroscopic particle diameter growth was measured when taken from a dehydrated to a humidified state for particle diameters between 30-350 nm (dry size) using a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA). Particles of a certain dry size all showed similar hygroscopic growth and the average diameter growth at RH=90% for 110/100 nm particles was 1.68 in the 1 MW boiler, and 1.52 in the 1.5 MW boiler. These growth factors are considerably higher in comparison to other combustion aerosol particles such as diesel exhaust, and are the result of the efficient combustion and the high concentration of alkali species in the fuel. The observed water uptake could be explained using the Zdanovskii-Stokes-Robinson (ZSR) mixing rule and a chemical composition of only potassium salts, taken from an Ion Chromatography analysis of filter sample (KCl, K{sub 2}SO{sub 4}, and K{sub 2}CO{sub 3}). Agglomerated particles collapsed and became more spherical when initially exposed to a moderately high relative humidity. When diluting with hot particle-free air, the fractal-like structures remained intact until humidified in the HTDMA. A method is presented to by which to estimate the fractal dimension of the agglomerated combustion aerosol and correct the measured mobility diameter hygroscopic growth to the more useful property volume growth. The fractal dimension was estimated to be {approx}2.5.

  7. Microphysical aerosol parameters of spheroidal particles via regularized inversion of lidar data

    Science.gov (United States)

    Samaras, Stefanos; Böckmann, Christine

    2015-04-01

    One of the main topics in understanding the aerosol impact on climate requires the investigation of the spatial and temporal variability of microphysical properties of particles, e.g., the complex refractive index, the effective radius, the volume and surface-area concentration, and the single-scattering albedo. Remote sensing is a technique used to monitor aerosols in global coverage and fill in the observational gap. This research topic involves using multi-wavelength Raman lidar systems to extract the microphysical properties of aerosol particles, along with depolarization signals to account for the non-sphericity of the latter. Given, the optical parameters (measured by a lidar), the kernel functions, which summarize the size, shape and composition of particles, we solve for the size distribution of the particles modeled by a Fredholm integral system and further calculate the refractive index. This model works well for spherical particles (e.g. smoke); the kernel functions are derived from relatively simplified formulas (Mie scattering theory) and research has led to successful retrievals for particles which at least resemble a spherical geometry (small depolarization ratio). Obviously, more complicated atmospheric structures (e.g dust) require employment of non-spherical kernels and/or more complicated models which are investigated in this paper. The new model is now a two-dimensional one including the aspect ratio of spheroidal particles. The spheroidal kernel functions are able to be calculated via T-Matrix; a technique used for computing electromagnetic scattering by single, homogeneous, arbitrarily shaped particles. In order to speed up the process and massively perform simulation tests, we created a software interface using different regularization methods and parameter choice rules. The following methods have been used: Truncated singular value decomposition and Pade iteration with the discrepancy principle, and Tikhonov regularization with the L

  8. Chemical Imaging of Ambient Aerosol Particles: Observational Constraints on Mixing State Parameterization

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Rachel; Wang, Bingbing; Laskin, Alexander; Riemer, Nicole; West, Matthew; Zhang, Qi; Sun, Yele; Yu, Xiao-Ying; Alpert, Peter A.; Knopf, Daniel A.; Gilles, Mary K.; Moffet, Ryan

    2015-09-28

    A new parameterization for quantifying the mixing state of aerosol populations has been applied for the first time to samples of ambient particles analyzed using spectro-microscopy techniques. Scanning transmission x-ray microscopy/near edge x-ray absorption fine structure (STXM/NEXAFS) and computer controlled scanning electron microscopy/energy dispersive x-ray spectroscopy (CCSEM/EDX) were used to probe the composition of the organic and inorganic fraction of individual particles collected on June 27th and 28th during the 2010 Carbonaceous Aerosols and Radiative Effects (CARES) study in the Central Valley, California. The first field site, T0, was located in downtown Sacramento, while T1 was located near the Sierra Nevada Mountains. Mass estimates of the aerosol particle components were used to calculate mixing state metrics, such as the particle-specific diversity, bulk population diversity, and mixing state index, for each sample. Both microscopy imaging techniques showed more changes over these two days in the mixing state at the T0 site than at the T1 site. The STXM data showed evidence of changes in the mixing state associated with a build-up of organic matter confirmed by collocated measurements and the largest impact on the mixing state was due to an increase in soot dominant particles during this build-up. The CCSEM/EDX analysis showed the presence of two types of particle populations; the first was dominated by aged sea salt particles and had a higher mixing state index (indicating a more homogeneous population), the second was dominated by carbonaceous particles and had a lower mixing state index.

  9. Chemical imaging of ambient aerosol particles: Observational constraints on mixing state parameterization

    Science.gov (United States)

    O'Brien, Rachel E.; Wang, Bingbing; Laskin, Alexander; Riemer, Nicole; West, Matthew; Zhang, Qi; Sun, Yele; Yu, Xiao-Ying; Alpert, Peter; Knopf, Daniel A.; Gilles, Mary K.; Moffet, Ryan C.

    2015-09-01

    A new parameterization for quantifying the mixing state of aerosol populations has been applied for the first time to samples of ambient particles analyzed using spectro-microscopy techniques. Scanning transmission X-ray microscopy/near edge X-ray absorption fine structure (STXM/NEXAFS) and computer-controlled scanning electron microscopy/energy dispersive X-ray spectroscopy (CCSEM/EDX) were used to probe the composition of the organic and inorganic fraction of individual particles collected on 27 and 28 June during the 2010 Carbonaceous Aerosols and Radiative Effects study in the Central Valley, California. The first field site, T0, was located in downtown Sacramento, while T1 was located near the Sierra Nevada Mountains. Mass estimates of the aerosol particle components were used to calculate mixing state metrics, such as the particle-specific diversity, bulk population diversity, and mixing state index, for each sample. The STXM data showed evidence of changes in the mixing state associated with a buildup of organic matter confirmed by collocated measurements, and the largest impact on the mixing state was due to an increase in soot dominant particles during this buildup. The mixing state from STXM was similar between T0 and T1, indicating that the increased organic fraction at T1 had a small effect on the mixing state of the population. The CCSEM/EDX analysis showed the presence of two types of particle populations: the first was dominated by aged sea-salt particles and had a higher mixing state index (indicating a more homogeneous population); the second was dominated by carbonaceous particles and had a lower mixing state index.

  10. Simulation of particle size distribution with a global aerosol model: contribution of nucleation to aerosol and CCN number concentrations

    Directory of Open Access Journals (Sweden)

    F. Yu

    2009-04-01

    Full Text Available An advanced particle microphysics model with a number of computationally efficient schemes has been incorporated into a global chemistry transport model (GEOS-Chem to simulate particle number size distributions and cloud condensation nuclei (CCN concentrations in the atmosphere. Size-resolved microphysics for secondary particles (i.e., those formed from gaseous species and sea salt has been treated in the present study. The growth of nucleated particles through the condensation of sulfuric acid vapor and equilibrium uptake of nitrate, ammonium, and secondary organic aerosol is explicitly simulated, along with the scavenging of secondary particles by primary particles (dust, black carbon, organic carbon, and sea salt. We calculate secondary particle formation rate based on ion-mediated nucleation (IMN mechanism and constrain the parameterizations of primary particle emissions with various observations. Our simulations indicate that secondary particles formed via IMN appear to be able to account for the particle number concentrations observed in many parts of troposphere. A comparison of the simulated annual mean concentrations of condensation nuclei larger than 10 nm (CN10 with those measured values show very good agreement (within a factor of two in near all 22 sites around the globe that have at least one full year of CN10 measurements. Secondary particles appear to dominate the number abundance in most parts of the troposphere. Calculated CCN concentration at supersaturation of 0.4% (CCN0.4 and the fraction of CCN0.4 that is secondary (fCCNsec have large spatial variations. Over the middle latitude in the Northern Hemisphere, zonally averaged CCN0.4 decreases from ~400–700 cm−3 in the boundary layer (BL to below 100 cm−3 above altitude of ~4 km, the corresponding fCCNsec values change from 50–60% to above ~70%. In the Southern Hemisphere, the zonally

  11. Simulation of particle size distribution with a global aerosol model: contribution of nucleation to aerosol and CCN number concentrations

    Directory of Open Access Journals (Sweden)

    F. Yu

    2009-10-01

    Full Text Available An advanced particle microphysics model with a number of computationally efficient schemes has been incorporated into a global chemistry transport model (GEOS-Chem to simulate particle number size distributions and cloud condensation nuclei (CCN concentrations in the atmosphere. Size-resolved microphysics for secondary particles (i.e., those formed from gaseous species and sea salt has been treated in the present study. The growth of nucleated particles through the condensation of sulfuric acid vapor and equilibrium uptake of nitrate, ammonium, and secondary organic aerosol is explicitly simulated, along with the scavenging of secondary particles by primary particles (dust, black carbon, organic carbon, and sea salt. We calculate secondary particle formation rate based on ion-mediated nucleation (IMN mechanism and constrain the parameterizations of primary particle emissions with various observations. Our simulations indicate that secondary particles formed via IMN appear to be able to account for the particle number concentrations observed in many parts of the troposphere. A comparison of the simulated annual mean concentrations of condensation nuclei larger than 10 nm (CN10 with those measured values show very good agreement (within a factor of two in near all 22 sites around the globe that have at least one full year of CN10 measurements. Secondary particles appear to dominate the number abundance in most parts of the troposphere. Calculated CCN concentration at supersaturation of 0.4% (CCN0.4 and the fraction of CCN0.4 that is secondary (fsecCCN have large spatial variations. Over the middle latitude in the Northern Hemisphere, zonally averaged CCN0.4 decreases from ~400–700 cm−3 in the boundary layer (BL to below 100 cm−3 above altitude of ~4 km, the corresponding fsecCCN values change from 50–60% to above ~70%. In the Southern Hemisphere, the zonally

  12. Power Spectral Densities of Atmospheric Aerosol Particle Counts

    Science.gov (United States)

    2010-01-01

    directly by absorbing and scattering radiation and indirectly by acting as cloud condensation nuclei (CCN). They are also important in atmospheric...are generated photochemically from vapor-phase terpenes emitted by plants; and combustion-generated particles from vehicular traffic, biomass

  13. Gas/aerosol-ash interaction in volcanic plumes: New insights from surface analyses of fine ash particles

    Science.gov (United States)

    Delmelle, Pierre; Lambert, Mathieu; Dufrêne, Yves; Gerin, Patrick; Óskarsson, Niels

    2007-07-01

    The reactions occurring between gases/aerosols and silicate ash particles in volcanic eruption plumes remain poorly understood, despite the fact that they are at the origin of a range of volcanic, environmental, atmospheric and health effects. In this study, we apply X-ray photoelectron spectroscopy (XPS), a surface-sensitive technique, to determine the chemical composition of the near-surface region (2-10 nm) of nine ash samples collected from eight volcanoes. In addition, atomic force microscopy (AFM) is used to image the nanometer-scale surface structure of individual ash particles isolated from three samples. We demonstrate that rapid acid dissolution of ash occurs within eruption plumes. This process is favoured by the presence of fluoride and is believed to supply the cations involved in the deposition of sulphate and halide salts onto ash. AFM imaging also has permitted the detection of extremely thin (< 10 nm) coatings on the surface of ash. This material is probably composed of soluble sulphate and halide salts mixed with sparingly soluble fluoride compounds. The surface approach developed here offers promising aspects for better appraising the role of gas/aerosol-ash interaction in dictating the ability of ash to act as sinks for various volcanic and atmospheric chemical species as well as sources for others.

  14. An inverse modeling procedure to determine particle growth and nucleation rates from measured aerosol size distributions

    Directory of Open Access Journals (Sweden)

    B. Verheggen

    2006-01-01

    Full Text Available Classical nucleation theory is unable to explain the ubiquity of nucleation events observed in the atmosphere. This shows a need for an empirical determination of the nucleation rate. Here we present a novel inverse modeling procedure to determine particle nucleation and growth rates based on consecutive measurements of the aerosol size distribution. The particle growth rate is determined by regression analysis of the measured change in the aerosol size distribution over time, taking into account the effects of processes such as coagulation, deposition and/or dilution. This allows the growth rate to be determined with a higher time-resolution than can be deduced from inspecting contour plots ('banana-plots''. Knowing the growth rate as a function of time enables the evaluation of the time of nucleation of measured particles of a certain size. The nucleation rate is then obtained by integrating the particle losses from time of measurement to time of nucleation. The regression analysis can also be used to determine or verify the optimum value of other parameters of interest, such as the wall loss or coagulation rate constants. As an example, the method is applied to smog chamber measurements. This program offers a powerful interpretive tool to study empirical aerosol population dynamics in general, and nucleation and growth in particular.

  15. Aerosol synthesis of nano and micro-scale zero valent metal particles from oxide precursors

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Jonathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM; Lesman, Zayd [UNM; Soliman, Haytham [UNM; Zea, Hugo [UNM

    2010-01-01

    In this work a novel aerosol method, derived form the batch Reduction/Expansion Synthesis (RES) method, for production of nano / micro-scale metal particles from oxides and hydroxides is presented. In the Aerosol-RES (A-RES) method, an aerosol, consisting of a physical mixture of urea and metal oxide or hydroxides, is passed through a heated oven (1000 C) with a residence time of the order of 1 second, producing pure (zero valent) metal particles. It appears that the process is flexible regarding metal or alloy identity, allows control of particle size and can be readily scaled to very large throughput. Current work is focused on creating nanoparticles of metal and metal alloy using this method. Although this is primarily a report on observations, some key elements of the chemistry are clear. In particular, the reducing species produced by urea decomposition are the primary agents responsible for reduction of oxides and hydroxides to metal. It is also likely that the rapid expansion that takes place when solid/liquid urea decomposes to form gas species influences the final morphology of the particles.

  16. Investigation of aerosol particle size distributions in the San Diego Bay area by means of multi-band transmissometry

    NARCIS (Netherlands)

    Jong, A.N. de; Eijk, A.M.J. van; Moerman, M.M.; Cohen, L.H.

    2006-01-01

    The presence of atmospheric aerosols along the line of sight of infrared and electro-optical sensors greatly determines the range performance of these devices. On the one hand the aerosol particles scatter background (including sun) radiance into the field of view of the sensor, on the other hand th

  17. Composition of carbonaceous smoke particles from prescribed burning of a Canadian boreal forest: 1. Organic aerosol characterization by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, M.A.; Laterza, C.; Newman, L.; Daum, P. [Brookhaven National Lab., Upton, NY (United States); Cofer, W.R. III; Levine, J.S. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center; Winstead, E.L. [Science Applications International Corporation, Hampton, VA (United States)

    1995-06-01

    In this study we examine the molecular organic constituents (C8 to C40 lipid compounds) collected as smoke particles from a Canadian boreal forest prescribed burn. Of special interest are (1) the molecular identity of polar organic aerosols, and (2) the amount of polar organic matter relative to the total mass of aerosol particulate carbon. Organic extracts of smoke aerosol particles show complex distributions of the lipid compounds when analyzed by capillary gas chromatography/mass spectrometry. The molecular constituents present as smoke aerosol are grouped into non-polar (hydrocarbons) and polar {minus}2 oxygen atoms) subtractions. The dominant chemical species found in the boreal forest smoke aerosol are unaltered resin compounds (C20 terpenes) which are abundant in unburned conifer wood, plus thermally altered wood lignins and other polar aromatic hydrocarbons. Our results show that smoke aerosols contain molecular tracers which are related to the biofuel consumed. These smoke tracers can be related structurally back to the consumed softwood and hardwood vegetation. In addition, combustion of boreal forest materials produces smoke aerosol particles that are both oxygen-rich and chemically complex, yielding a carbonaceous aerosol matrix that is enriched in polar substances. As a consequence, emissions of carbonaceous smoke particles from large-scale combustion of boreal forest land may have a disproportionate effect on regional atmospheric chemistry and on cloud microphysical processes.

  18. Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

    Science.gov (United States)

    Forestieri, Sara D.; Cornwell, Gavin C.; Helgestad, Taylor M.; Moore, Kathryn A.; Lee, Christopher; Novak, Gordon A.; Sultana, Camille M.; Wang, Xiaofei; Bertram, Timothy H.; Prather, Kimberly A.; Cappa, Christopher D.

    2016-07-01

    The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of predominately submicron SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. Optically weighted GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions. The mean optically weighted SSA diameters were 530 and 570 nm for the indoor and outdoor MARTs, respectively. The GF(85 %) measurements were made concurrently with online particle composition measurements, including bulk composition (using an Aerodyne high-resolution aerosol mass spectrometer) and single particle (using an aerosol time-of-flight mass spectrometer) measurement, and a variety of water-composition measurements. During both microcosm experiments, the observed optically weighted GF(85 %) values were depressed substantially relative to pure inorganic sea salt by 5 to 15 %. There was also a time lag between GF(85 %) depression and the peak chlorophyll a (Chl a) concentrations by either 1 (indoor MART) or 3-to-6 (outdoor MART) days. The fraction of organic matter in the SSA particles generally increased after the Chl a peaked, also with a time lag, and ranged from about 0.25 to 0.5 by volume. The observed depression in the GF(85 %) values (relative to pure sea salt) is consistent with the large observed volume fractions of non-refractory organic matter (NR-OM) comprising the SSA. The GF(85 %) values exhibited a reasonable negative

  19. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-04-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1 h, diesel soot particles were found to be stable up to 480°C, but complete combustion occurred in a narrow temperature interval between about 490 and 510°C. After diesel soot combustion, minute quantities of ''ash'' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  20. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-01-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1h, diesel soot particles were found to be stable up to 470°C, but complete combustion occurred in a narrow temperature interval between about 480 and 510°C. After diesel soot combustion, minute quantities of 'ash' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  1. Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

    Science.gov (United States)

    Guyon, P.; Frank, G. P.; Welling, M.; Chand, D.; Artaxo, P.; Rizzo, L.; Nishioka, G.; Kolle, O.; Fritsch, H.; Silva Dias, M. A. F.; Gatti, L. V.; Cordova, A. M.; Andreae, M. O.

    2005-11-01

    As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14-32 cm-3 ppb-1 in most of the investigated smoke plumes. Particle number emission ratios have to our knowledge not been previously measured in tropical deforestation fires, but our results are in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependent on the fire conditions (combustion efficiency). Variability in ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2), which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, reflecting the fact that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF) for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC) fraction of emissions that are not sampled by the aircraft, which increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from the boundary layer (BL) to the cloud detrainment layer (CDL) and the free troposphere (FT) was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol particles

  2. Transmission Electron Microscopy Analysis of Tarball Formation and Volatility from Biomass-burning Aerosol Particles during the 2013 BBOP Campaign

    Science.gov (United States)

    Buseck, P. R.; Adachi, K.; Chand, D.; Kleinman, L. I.; Sedlacek, A. J., III

    2014-12-01

    Tar balls, a subset of organic aerosol that is characterized by spherical shape and amorphous composition, are presumed to be brown-carbon (BrC) particles that contribute to light absorption in the atmosphere. Because of their distinctive shapes, compositions, and lack of crystallinity, tar balls are uniquely identifiable using transmission electron microscopy (TEM). Using samples collected during BBOP, we performed a detailed investigation of their compositions, formation processes, and occurrence. They primarily originated from wildfires and are most abundant in relatively aged plumes (>several hours from emission). Their features are similar to those from Mexico measured during the 2006 MILAGRO campaign, but their number fractions are more abundant in the Idaho, Oregon, and Washington samples of BBOP. In order to determine the TB robustness with respect to heating, an experiment was carried out on a TEM grid containing a mixture of organic particles, nanosphere soot, and TBs during which the sample temperature was ramped from ~30 to 650 ºC. The TEM results collected at 30 and 600 ºC, the latter representing the filament temperature used by the AMS, indicate that material of lower volatility is lost by 600 ºC. Although there was some loss of material during the 15-minute temperature ramp, TBs were still present at the higher temperature. These preliminary findings suggest that the efficiency of AMS detection of TBs may be significantly less than unity and potentially translate to an underreporting of the aerosol mass for wildfire plumes. If tar balls have low AMS detection efficiencies, an underestimate in organic aerosol mass will result.

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

    Science.gov (United States)

    Sheridan, Patrick J.

    1999-01-01

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

  4. Simultaneous ion luminescence imaging and spectroscopy of individual aerosol particles with external proton or helium microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada.wataru@gunma-u.ac.jp [Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2014-08-01

    Simultaneous microscopic imaging and spectroscopy of individual aerosol particles were performed with an external microbeam. Visible luminescence induced by the external microbeam was successfully used as a probe to detect organic contaminants in the targets. Combined ion luminescence (IL)/particle-induced X-ray emission (PIXE) analysis of the aerosol targets revealed microscopic chemical and elemental composition distributions under ambient atmospheric conditions. The simple confocal micro-optics for the IL spectroscopy and microscopic imaging were sufficiently sensitive for detecting these molecules at sub-parts per million concentrations and at a wavelength resolution of less than 5 nm. The IL spectra were monitored to prevent severe damage to the samples. Furthermore, our IL system has the advantage that it is simple to add to a conventional micro-PIXE system.

  5. The collision efficiency of spherical dioctyl phthalate aerosol particles in the Brownian coagulation

    Institute of Scientific and Technical Information of China (English)

    Feng Yu; Lin Jian-Zhong

    2008-01-01

    The collision efficiency in the Brownian coagulation is investigated. A new mechanical model of collision between two identical spherical particles is proposed, and a set of corresponding collision equations is established. The equations are solved numerically, thereby obtaining the collision efficiency for the monodisperse dioctyl phthalate spherical aerosols with diameters ranging from 100 to 760 nm in the presence of van der Waals force and the elastic deformation force.The calculated collision efficiency, in agreement with the experimental data qualitatively, decreases with the increase of particle diameter except a small peak appearing in the particles with a diameter of 510 nm. The results show that the interparticle elastic deformation force cannot be neglected in the computation of particle Brownian coagulation.Finally, a set of new expressions relating collision efficiency to particle diameter is established.

  6. Measurement of aerosol-particle trajectories using a structured laser beam.

    Science.gov (United States)

    Herzog, William D; Tysk, Shane M; Tardiff, David W; Cappiello, Gregory G; Jong, Jason M; Jeys, Thomas H; Hoffeld, Ronald H; Sanchez, Antonio; Daneu, Vincenzo

    2007-06-01

    What is believed to be a new concept for the measurement of micrometer-sized particle trajectories in an inlet air stream is introduced. The technique uses a light source and a mask to generate a spatial pattern of light within a volume in space. Particles traverse the illumination volume and elastically scatter light to a photodetector where the signal is recorded in time. The detected scattering waveform is decoded to find the particle trajectory. A design is presented for the structured laser beam, and the accuracy of the technique in determining particle position is demonstrated. It is also demonstrated that the structured laser beam can be used to measure and then correct for the spatially dependent instrument-response function of an optical-scattering-based particle-sizing system for aerosols.

  7. Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2010-02-01

    Full Text Available This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO field campaign conducted in Mexico City metropolitan area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX. As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0 the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium coated with organic material. At the T1 and T2 sites, located northeast of T0 (~29 km and ~65 km, respectively, the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

  8. Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2009-08-01

    Full Text Available This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO field campaign conducted in Mexico City Metropolitan Area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX. As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0 the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium coated with organic material. At the T1 and T2 sites, located northeast of T0 (~29 km and ~65 km, respectively, the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

  9. Microscopic Characterization of Carbonaceous Aerosol Particle Aging in the Outflow from Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Moffet, R. C.; Henn, T. R.; Tivanski, A. V.; Hopkins, R. J.; Desyaterik, Y.; Kilcoyne, A. L. D.; Tyliszczak, T.; Fast, J.; Barnard, J.; Shutthanandan, V.; Cliff, S.S.; Perry, K. D.; Laskin, A.; Gilles, M. K.

    2009-09-16

    This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in Mexico City Metropolitan Area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS) and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX). As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon) decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0) the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium) coated with organic material. At the T1 and T2 sites, located northeast of T0 (~;;29 km and ~;;65 km, respectively), the fraction of homogenously mixed organic particles increased in both size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

  10. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-16

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  11. Liquid-liquid phase separation in aerosol particles: Imaging at the Nanometer Scale

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Rachel; Wang, Bingbing; Kelly, Stephen T.; Lundt, Nils; You, Yuan; Bertram, Allan K.; Leone, Stephen R.; Laskin, Alexander; Gilles, Mary K.

    2015-04-21

    Atmospheric aerosols can undergo phase transitions including liquid-liquid phase separation (LLPS) while responding to changes in the ambient relative humidity (RH). Here, we report results of chemical imaging experiments using environmental scanning electron microscopy (ESEM) and scanning transmission x-ray microscopy (STXM) to investigate the LLPS of micron sized particles undergoing a full hydration-dehydration cycle. Internally mixed particles composed of ammonium sulfate (AS) and either: limonene secondary organic carbon (LSOC), a, 4-dihydroxy-3-methoxybenzeneaceticacid (HMMA), or polyethylene glycol (PEG-400) were studied. Events of LLPS with apparent core-shell particle morphology were observed for all samples with both techniques. Chemical imaging with STXM showed that both LSOC/AS and HMMA/AS particles were never homogeneously mixed for all measured RH’s above the deliquescence point and that the majority of the organic component was located in the shell. The shell composition was estimated as 65:35 organic: inorganic in LSOC/AS and as 50:50 organic: inorganic for HMMA/AS. PEG-400/AS particles showed fully homogeneous mixtures at high RH and phase separated below 89-92% RH with an estimated 50:50% organic to inorganic mix in the shell. These two chemical imaging techniques are well suited for in-situ analysis of the hygroscopic behavior, phase separation, and surface composition of collected ambient aerosol particles.

  12. Effect of humidity on nitric acid uptake to mineral dust aerosol particles

    Directory of Open Access Journals (Sweden)

    A. Vlasenko

    2006-01-01

    Full Text Available This study presents the first laboratory observation of HNO3 uptake by airborne mineral dust particles. The model aerosols were generated by dry dispersion of Arizona Test Dust (ATD, SiO2, and by nebulizing a saturated solution of calcium carbonate. The uptake of 13N-labeled gaseous nitric acid was observed in a flow reactor on the 0.2–2 s reaction time scale at room temperature and atmospheric pressure. The amount of nitric acid appearing in the aerosol phase at the end of the flow tube was found to be a linear function of the aerosol surface area. SiO2 particles did not show any significant uptake, while the CaCO3 aerosol was found to be more reactive than ATD. Due to the smaller uncertainty associated with the reactive surface area in the case of suspended particles as compared to bulk powder samples, we believe that we provide an improved estimate of the rate of uptake of HNO3 to mineral dust. The fact that the rate of uptake was smaller at a concentration of 1012 than at 1011 was indicative of a complex uptake mechanism. The uptake coefficient averaged over the first 2 s of reaction time at a concentration of 1012 molecules cm-3 was found to increase with increasing relative humidity, from 0.022±0.007 at 12% RH to 0.113±0.017 at 73% RH , which was attributed to an increasing degree of solvation of the more basic minerals. The extended processing of the dust by higher concentrations of HNO3 at 85% RH led to a water soluble coating on the particles and enhanced their hygroscopicity.

  13. Interaction of aerosol particles composed of protein and saltswith water vapor: hygroscopic growth and microstructural rearrangement

    OpenAIRE

    Mikhailov, E.; Vlasenko, S.; Niessner, R.; U. Pöschl

    2004-01-01

    The interaction of aerosol particles in the 100–200 nm size range composed of the protein bovine serum albumin (BSA) and the inorganic salts sodium chloride and ammonium nitrate with water vapor at ambient temperature and pressure (25°C, 1 atm) has been investigated by hygroscopicity tandem differential mobility analyzer (H-TDMA) experiments complemented by transmission electron microscopy (TEM) and Köhler theory calculations. BSA was chosen as a well-defined model subs...

  14. Infrared spectroscopic methods for the study of aerosol particles using White cell optics: Development and characterization of a new aerosol flow tube

    Science.gov (United States)

    Nájera, Juan J.; Fochesatto, Javier G.; Last, Deborah J.; Percival, Carl J.; Horn, Andrew B.

    2008-12-01

    A description of a new aerosol flow tube apparatus for measurements in situ under atmospherically relevant conditions is presented here. The system consists of a laboratory-made nebulizer generation system and a flow tube with a White cell-based Fourier transform IR for the detection system. An assessment of the White cell coupled to the flow tube was carried out by an extensive set of experiments to ensure the alignment of the infrared beam and optimize the performance of this system. The detection limit for CO was established as (1.0±0.3) ppm and 16 passes was chosen as the optimum number of passes to be used in flow tube experiments. Infrared spectroscopy was used to characterize dry aerosol particles in the flow tube. Pure particles composed of ammonium sulfate or sodium chloride ranging between 0.8 and 2.1 μm for size diameter and (0.8-4.9)×106 particles/cm3 for density number were generated by nebulization of aqueous solutions. Direct measurements of the aerosol particle size agree with size spectra retrieved from inversion of the extinction measurements using Mie calculations, where the difference residual value is in the order of 0.2%. The infrared detection limit for ammonium sulfate aerosol particles was determined as dp=0.9 μm and N =5×103 particles/cm3 with σ =1.1 by Mie calculation. Alternatively, Mie calculations were performed to determine the flexibility in varying the optical length when aerosol particles are sent by the injector. The very good agreement between the values retrieved for aerosol particles injected through the flow tube or through the injector clearly validates the estimation of the effective optical path length for the injector. To determine the flexibility in varying the reaction zone length, analysis of the extinction spectra as function of the position of the injector was carried out by monitoring the integrated area of different absorption modes of the ammonium sulfate. We conclude that the aerosol loss in the flow tube

  15. Aerosol and CCN properties at Princess Elisabeth station, East Antarctica: seasonality, new particle formation events and properties around precipitation events

    Science.gov (United States)

    Mangold, Alexander; Laffineur, Quentin; De Backer, Hugo; Herenz, Paul; Wex, Heike; Gossart, Alexandra; Souverijns, Niels; Gorodetskaya, Irina; Van Lipzig, Nicole

    2016-04-01

    Since 2010, several complementary ground-based instruments for measuring the aerosol composition of the Antarctic atmosphere have been operated at the Belgian Antarctic research station Princess Elisabeth, in Dronning Maud Land, East Antarctica (71.95° S, 23.35° E, 1390 m asl.). In addition, three ground-based remote sensing instruments for cloud and precipitation observations have been installed for continuous operation, including a ceilometer (cloud base height, type, vertical extent), a 24 Ghz micro-rain radar (vertical profiles of radar effective reflectivity and Doppler velocity), and a pyrometer (cloud base temperature). The station is inhabited from November to end of February and operates under remote control during the other months. In this contribution, the general aerosol and cloud condensation nuclei (CCN) properties will be described with a special focus on new particle formation events and around precipitation events. New particle formation events are important for the atmospheric aerosol budget and they also show that aerosols are not only transported to Antarctica but are also produced there, also inland. Aerosols are essential for cloud formation and therefore also for precipitation, which is the only source for mass gain of the Antarctic ice sheet. Measured aerosol properties comprise size distribution, total number, total mass concentration, mass concentration of light-absorbing aerosol and absorption coefficient and total scattering coefficient. In addition, a CCN counter has been operated during austral summers 2013/14, 2014/15 and 2015/16. The baseline total number concentration N-total was around some hundreds of particles/cm3. During new particle formation events N-total increased to some thousands of particles/cm3. Simultaneous measurements of N-total, size distribution and CCN number revealed that mostly the number of particles smaller than 100 nm increased and that the concentration of cloud condensation nuclei increased only very

  16. Radon decay products and 10–1100 nm aerosol particles in Postojna Cave

    Directory of Open Access Journals (Sweden)

    M. Bezek

    2013-03-01

    Full Text Available At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn decay products and the number concentration and size distribution of aerosol particles in the size range of 10–1100 nm were monitored, with the focus on the unattached fraction (fun of radon decay products (RnDPs, a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm−3 than in winter (2800 cm−3, and was dominated by 50 nm particles (related to the attached RnDPs in winter. This explains the higher fun values in summer (0.75 and the lower winter measurement (0.04 and, consequently, DCFD values of 43.6 and 13.1 mSv WLM−1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

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

    Science.gov (United States)

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

    2010-11-01

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

  18. Concentrations, size distributions and temporal variations of fluorescent biological aerosol particles in southern tropical India

    Science.gov (United States)

    Valsan, Aswathy; Krishna R, Ravi; CV, Biju; Huffman, Alex; Poschl, Ulrich; Gunthe, Sachin

    2015-04-01

    Biological aerosols constitute a wide range of dead and alive biological materials and structures that are suspended in the atmosphere. They play an important role in the atmospheric physical, chemical and biological processes and health of living being by spread of diseases among humans, plants, and, animals. The atmospheric abundance, sources, physical properties of PBAPs as compared to non-biological aerosols, however, is poorly characterized. The Indian tropical region, where large fraction of the world's total population is residing, experiences a distinctive meteorological phenomenon by means of Indian Summer Monsoon (IMS). Thus, the properties and characteristics of biological aerosols are also expected to be very diverse over the Indian subcontinent depending upon the seasons. Here we characterize the number concentration and size distribution of Fluorescent Biological Aerosol Particles (FBAP) at a high altitude continental site, Munnar (10.09 N, 77.06 E; 1605 m asl) in South India during the South-West monsoon, which constitute around 80 percent of the annual rainfall in Munnar. Continuous three months measurements (from 01 June 2014 to 21 Aug 2104) FBAPs were carried out at Munnar using Ultra Violet Aerodynamic Particle Sizer (UVAPS) during IMS. The mean number and mass concentration of coarse FBAP averaged over the entire campaign was 1.7 x 10-2 cm-3 and 0.24 µg m-3 respectively, which corresponds to 2 percent and 6 percent of total aerosol particle number and mass concentration. In agreement to other previous measurements the number size distribution of FBAP also peaks at 3.2 micron indicating the strong presence of fungal spores. This was also supported by the Scanning Electron Microscopic analysis of bioaerosols on filter paper. They also displayed a strong diurnal cycle with maximum concentration occurring at early morning hours. During periods of heavy and continuous rain where the wind is consistently blowing from South-West direction it was

  19. Observations of residual submicron fine aerosol particles related to cloud and fog processing during a major pollution event in Beijing

    Science.gov (United States)

    Li, Zhengqiang; Eck, Tom; Zhang, Ying; Zhang, Yuhuan; Li, Donghui; Li, Li; Xu, Hua; Hou, Weizhen; Lv, Yang; Goloub, Philippe; Gu, Xingfa

    2014-04-01

    Residual aerosols, the particles left behind after droplet evaporation, are important tracers for aerosols processed by cloud and/or fog. Based on ground-based CIMEL sun-sky radiometer measurements during an extreme winter pollution event in Beijing, we present observations of the decrease of residual aerosol with dissipation of cloud and an unusual case of residual aerosol increase after partial dissipation of fog. This unusual increase might be an important mechanism for the haze growth in polluted regions. The aerosol single scattering albedo is found to increase with the increase of residual aerosol. We also find that residual aerosol dominated cases with significant water content gain can occur in a short time (e.g. one hour) with the increase of aerosol volume size and decrease of particle number. A lognormal residual aerosol size distribution model is proposed based on sun-sky radiometer measurements with center peak radius at 0.44 micron and geometric standard deviation of about 1.49.

  20. Fluorescence spectra and elastic scattering characteristics of atmospheric aerosol in Las Cruces, New Mexico, USA: Variability of concentrations and possible constituents and sources of particles in various spectral clusters

    Science.gov (United States)

    Pinnick, R. G.; Fernandez, E.; Rosen, J. M.; Hill, S. C.; Wang, Y.; Pan, Y. L.

    2013-02-01

    uncorrelated with those in any other cluster. No clear distinction in fluorescent aerosol characteristics can be seen for different air mass trajectories arriving at the sampling site, suggesting that fluorescent aerosol particles are primarily of local origin. Integrations of the single-particle UV-LIF spectra over approximate 24 h time intervals reveal two broad peaks around 350 nm and 450 nm (for 263 nm excitation); the 450 nm peak is somewhat similar to that measured previously for water soluble organic carbon derived from aerosol collections. The 350 nm peak apparently has not been seen before in measurements of aerosol collections and may derive from non-soluble primary biological aerosol particles such as fungal spores. Further measurements are needed to investigate in more detail the generality of these results.

  1. Size distribution of aerosol particles: comparison between agricultural and industrial areas in Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Tadros, M.T.Y.; Madkour, M. [Mansoura Univ., Physics Dept., Mansoura (Egypt); Elmetwally, M. [Egyptian Meteorological Authority, Abbasyia-Cairo (Egypt)

    1999-07-01

    Mie theory has been used in this work to obtain a theoretical calculation of the size distribution of aerosol particles by using tabulated mean of the Angstrom wavelength exponent {alpha}{sub o}. Comparison was done between an industrial polluted area (Helwan, which is a neighbor to Cairo city), and an agricultural relatively unpolluted area (Mansoura, about 140 km from Cairo). The results show that the size distribution obeys the Junge power law. The size of particles in the polluted area is larger than that in the unpolluted area. (Author)

  2. Long-term aerosol measurements in Gran Canaria, Canary Islands: Particle concentration, sources and elemental composition

    Science.gov (United States)

    Gelado-Caballero, MaríA. D.; López-GarcíA, Patricia; Prieto, Sandra; Patey, Matthew D.; Collado, Cayetano; HéRnáNdez-Brito, José J.

    2012-02-01

    There are very few sets of long-term measurements of aerosol concentrations over the North Atlantic Ocean, yet such data is invaluable in quantifying atmospheric dust inputs to this ocean region. We present an 8-year record of total suspended particles (TSP) collected at three stations on Gran Canaria Island, Spain (Taliarte at sea level, Tafira 269 m above sea level (a.s.l.) and Pico de la Gorra 1930 m a.s.l.). Using wet and dry deposition measurements, the mean dust flux was calculated at 42.3 mg m-2 d-1. Air mass back trajectories (HYSPLIT, NOAA) suggested that the Sahara desert is the major source of African dust (dominant during 32-50% of days), while the Sahel desert was the major source only 2-10% of the time (maximum in summer). Elemental composition ratios of African samples indicate that, despite the homogeneity of the dust in collected samples, some signatures of the bedrocks can still be detected. Differences were found for the Sahel, Central Sahara and North of Sahara regions in Ti/Al, Mg/Al and Ca/Al ratios, respectively. Elements often associated with pollution (Pb, Cd, Ni, Zn) appeared to share a common origin, while Cu may have a predominantly local source, as suggested by a decrease in the enrichment factor (EF) of Cu during dust events. The inter-annual variability of dust concentrations is investigated in this work. During winter, African dust concentration measurements at the Pico de la Gorra station were found to correlate with the North Atlantic Oscillation (NAO) index.

  3. Study of particle size distribution and formation mechanism of radioactive aerosols generated in high-energy neutron fields

    CERN Document Server

    Endo, A; Noguchi, H; Tanaka, S; Iida, T; Furuichi, S; Kanda, Y; Oki, Y

    2003-01-01

    The size distributions of sup 3 sup 8 Cl, sup 3 sup 9 Cl, sup 8 sup 2 Br and sup 8 sup 4 Br aerosols generated by irradiations of argon and krypton gases containing di-octyl phthalate (DOP) aerosols with 45 MeV and 65 MeV quasi-monoenergetic neutrons were measured in order to study the formation mechanism of radioactive particles in high energy radiation fields. The effects of the size distribution of the radioactive aerosols on the size of the added DOP aerosols, the energy of the neutrons and the kinds of nuclides were studied. The observed size distributions of the radioactive particles were explained by attachment of the radioactive atoms generated by the neutron-induced reactions to the DOP aerosols. (author)

  4. PM1 geochemical and mineralogical characterization using SEM-EDX to identify particle origin - Agri Valley pilot area (Basilicata, southern Italy)

    Science.gov (United States)

    Margiotta, S.; Lettino, A.; Speranza, A.; Summa, V.

    2015-07-01

    A PM1 geochemical and mineralogical study using Scanning Electron Microscopy (SEM) was performed on a pilot site in the Agri Valley which is close to the oil pre-treatment plant (C.O.V.A) of Europe's largest on-shore hydrocarbon reservoir. The study identified PM1 geochemical and mineralogical characters in the period before, during and immediately after a burning torch flare event. The finer fraction (DFe μm) consisted mainly of secondary particles and soot. In the coarser fraction (DFe ≥ 0.7 μm), natural particles originating from crustal erosion and soot were abundant. Fine quartz particles and lower Al / Si ratios are markers for desert dust origin, proving that a Saharan dust episode which occurred during the observation period played a significant role in supplying geogenic aerosol components to the PM1. Largest amounts of ≥ 0.7 μm fraction particles observed on the day of flare event may be due to a greater supply of Saharan geogenic particles. Soot had been significantly increasing long before the flare event, suggesting that this increase is also related to other causes, although we cannot exclude a contribution from flaring. S-rich aerosol consisted mainly of mixed particles originating from deposition and heterogeneous nucleation of secondary sulfates on mineral dust. Only-S particles were identified in the ≥ 0.7 μm fraction following the flare event. These particles may be indicators of larger amounts of sulphur in the atmosphere.

  5. 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.

  6. Formation of Secondary Particulate Matter by Reactions of Gas Phase Hexanal with Sulfate Aerosol Particles

    Science.gov (United States)

    Zhang, J.

    2003-12-01

    The formation of secondary particulate matter from the atmospheric oxidation of organic compounds can significantly contribute to the particulate burden, but the formation of organic secondary particulate matter is poorly understood. One way of producing organic secondary particulate matter is the oxidation of hydrocarbons with seven or more carbon atoms to get products with low vapor pressure. However, several recent reports suggest that relatively low molecular weight carbonyls can enter the particle phase by undergoing heterogeneous reactions. This may be a very important mechanism for the formation of organic secondary particulate matter. Atmospheric aldehydes are important carbonyls in the gas phase, which form via the oxidation of hydrocarbons emitted from anthropogenic and biogenic sources. In this poster, we report the results on particle growth by the heterogeneous reactions of hexanal. A 5 L Continuous Stirred Tank Reactor (CSTR) is set up to conduct the reactions in the presence of seed aerosol particles of deliquesced ammonia bisulfate. Hexanal is added into CSTR by syringe pump, meanwhile the concentrations of hexanal are monitored with High Pressure Liquid Chromatograph (HPLC 1050). A differential Mobility Analyzer (TSI 3071) set to an appropriate voltage is employed to obtain monodisperse aerosols, and another DMA associated with a Condensation Nuclear Counter (TSI 7610) is used to measure the secondary particle size distribution by the reaction in CSTR. This permits the sensitive determination of particle growth due to the heterogeneous reaction, very little growth occurs when hexanal added alone. Results for the simultaneous addition of hexanal and alcohols will also be presented.

  7. Liquid-liquid phase separation in aerosol particles: imaging at the nanometer scale.

    Science.gov (United States)

    O'Brien, Rachel E; Wang, Bingbing; Kelly, Stephen T; Lundt, Nils; You, Yuan; Bertram, Allan K; Leone, Stephen R; Laskin, Alexander; Gilles, Mary K

    2015-04-21

    Atmospheric aerosols can undergo phase transitions including liquid-liquid phase separation (LLPS) while responding to changes in the ambient relative humidity (RH). Here, we report results of chemical imaging experiments using environmental scanning electron microscopy (ESEM) and scanning transmission X-ray microscopy (STXM) to investigate the LLPS of micrometer-sized particles undergoing a full hydration-dehydration cycle. Internally mixed particles composed of ammonium sulfate (AS) and either: limonene secondary organic carbon (LSOC), α, 4-dihydroxy-3-methoxybenzeneaceticacid (HMMA), or polyethylene glycol (PEG-400) were studied. Events of LLPS were observed for all samples with both techniques. Chemical imaging with STXM showed that both LSOC/AS and HMMA/AS particles were never homogeneously mixed for all measured RH's above the deliquescence point and that the majority of the organic component was located in the outer phase. The outer phase composition was estimated as 65:35 organic: inorganic in LSOC/AS and as 50:50 organic: inorganic for HMMA/AS. PEG-400/AS particles showed fully homogeneous mixtures at high RH and phase separated below 89-92% RH with an estimated 70:30% organic to inorganic mix in the outer phase. These two chemical imaging techniques are well suited for in situ analysis of the hygroscopic behavior, phase separation, and surface composition of collected ambient aerosol particles.

  8. Differences in aerosol absorption Ångström exponents between correction algorithms for particle soot absorption photometer measured on South African Highveld

    Science.gov (United States)

    Backman, J.; Virkkula, A.; Vakkari, V.; Beukes, J. P.; Van Zyl, P.; Josipovic, M.; Piketh, S.; Tiitta, P.; Chiloane, K.; Petäjä, T.; Kulmala, M.; Laakso, L.

    2014-09-01

    Absorption Ångstrom exponents (AAE) calculated from filter-based absorption measurements are often used to give information on the origin of the ambient aerosol, for example to distinguish between urban pollution and biomass burning aerosol. Filter-based absorption measurements are a widely used method and are commonly used at aerosol monitoring stations globally. Several correction algorithms are used to account for the artifacts associated with filter-based absorption techniques. These algorithms are of profound importance when determining the absolute amount of absorption by the aerosol. However, this study shows that there are significant differences between the AAEs calculated from these corrections. The study also shows that the difference between AAEs calculated using different corrections can lead to conflicting conclusions on the type of aerosol for the same data set. In this work the AAEs were calculated from data measured with a three-wavelength Particle Soot Absorption Photometer (PSAP) at Elandsfontein on deployed on the South African Highveld for 23 months. The sample air of the PSAP was diluted to prolong filter change intervals. The dilution-corrected PSAP showed a good agreement with a non-diluted MAAP. Thus, the study also shows that the applicability of the PSAP can be extended to remote sites are not often visited or suffer from high levels of pollution.

  9. Differences in aerosol absorption Ångström exponents between correction algorithms for particle soot absorption photometer measured on South African Highveld

    Directory of Open Access Journals (Sweden)

    J. Backman

    2014-09-01

    Full Text Available Absorption Ångstrom exponents (AAE calculated from filter-based absorption measurements are often used to give information on the origin of the ambient aerosol, for example to distinguish between urban pollution and biomass burning aerosol. Filter-based absorption measurements are a widely used method and are commonly used at aerosol monitoring stations globally. Several correction algorithms are used to account for the artifacts associated with filter-based absorption techniques. These algorithms are of profound importance when determining the absolute amount of absorption by the aerosol. However, this study shows that there are significant differences between the AAEs calculated from these corrections. The study also shows that the difference between AAEs calculated using different corrections can lead to conflicting conclusions on the type of aerosol for the same data set. In this work the AAEs were calculated from data measured with a three-wavelength Particle Soot Absorption Photometer (PSAP at Elandsfontein on deployed on the South African Highveld for 23 months. The sample air of the PSAP was diluted to prolong filter change intervals. The dilution-corrected PSAP showed a good agreement with a non-diluted MAAP. Thus, the study also shows that the applicability of the PSAP can be extended to remote sites are not often visited or suffer from high levels of pollution.

  10. Particle Loss Calculator – a new software tool for the assessment of the performance of aerosol inlet systems

    Directory of Open Access Journals (Sweden)

    S.-L. von der Weiden

    2009-09-01

    Full Text Available Most aerosol measurements require an inlet system to transport aerosols from a select sampling location to a suitable measurement device through some length of tubing. Such inlet systems must be optimized to minimize aerosol sampling artifacts and maximize sampling efficiency. In this study we introduce a new multifunctional software tool (Particle Loss Calculator, PLC that can be used to quickly determine aerosol sampling efficiency and particle transport losses due to passage through arbitrary tubing systems. The software employs relevant empirical and theoretical relationships found in established literature and accounts for the most important sampling and transport effects that might be encountered during deployment of typical, ground-based ambient aerosol measurements through a constant-diameter sampling probe. The software treats non-isoaxial and non-isokinetic aerosol sampling, aerosol diffusion and sedimentation as well as turbulent inertial deposition and inertial deposition in bends and contractions of tubing. This software was validated through comparison with experimentally determined particle losses for several tubing systems bent to create various diffusion, sedimentation and inertial deposition properties. As long as the tube geometries are not "too extreme", agreement is satisfactory. We discuss the conclusions of these experiments, the limitations of the software and present three examples of the use of the Particle Loss Calculator in the field.

  11. Particle Loss Calculator – a new software tool for the assessment of the performance of aerosol inlet systems

    Directory of Open Access Journals (Sweden)

    S.-L. von der Weiden

    2009-04-01

    Full Text Available Most aerosol measurements require an inlet system to transport aerosols from a select sampling location to a suitable measurement device through some length of tubing. Such inlet systems must be optimized to minimize aerosol sampling artifacts and maximize sampling efficiency. In this study we introduce a new multifunctional software tool (Particle Loss Calculator, PLC that can be used to quickly determine aerosol sampling efficiency and particle transport losses due to passage through arbitrary tubing systems. The software employs relevant empirical and theoretical relationships found in established literature and accounts for the most important sampling and transport effects that might be encountered during deployment of typical, ground-based ambient aerosol measurements. The software treats non-isoaxial and non-isokinetic aerosol sampling, aerosol diffusion and sedimentation as well as turbulent inertial deposition and inertial deposition in bends and contractions of tubing. This software was validated through comparison with experimentally determined particle losses for several tubing systems bent to create various diffusion, sedimentation and inertial deposition properties. As long as the tube geometries are not "too extreme", agreement is satisfactory. We discuss the conclusions of these experiments, the limitations of the software and present three examples of the use of the Particle Loss Calculator in the field.

  12. Constant size, variable density aerosol particles by ultrasonic spray freeze drying.

    Science.gov (United States)

    D'Addio, Suzanne M; Chan, John Gar Yan; Kwok, Philip Chi Lip; Prud'homme, Robert K; Chan, Hak-Kim

    2012-05-10

    This work provides a new understanding of critical process parameters involved in the production of inhalation aerosol particles by ultrasonic spray freeze drying to enable precise control over particle size and aerodynamic properties. A series of highly porous mannitol, lysozyme, and bovine serum albumin (BSA) particles were produced, varying only the solute concentration in the liquid feed, c(s), from 1 to 5 wt%. The particle sizes of mannitol, BSA, and lysozyme powders were independent of solute concentration, and depend only on the drop size produced by atomization. Both mannitol and lysozyme formulations showed a linear relationship between the computed Fine Particle Fraction (FPF) and the square root of c(s), which is proportional to the particle density, ρ, given a constant particle size d(g). The FPF decreased with increasing c(s) from 57.0% to 16.6% for mannitol and 44.5% to 17.2% for lysozyme. Due to cohesion, the BSA powder FPF measured by cascade impaction was less than 10% and independent of c(s). Ultrasonic spray freeze drying enables separate control over particle size, d(g), and aerodynamic size, d(a) which has allowed us to make the first experimental demonstration of the widely accepted rule d(a)=d(g)(ρ/ρ(o))(1/2) with particles of constant d(g), but variable density, ρ (ρ(o) is unit density).

  13. Experimental investigation of homogeneous freezing of sulphuric acid particles in the aerosol chamber AIDA

    Directory of Open Access Journals (Sweden)

    O. Möhler

    2002-10-01

    Full Text Available The homogeneous freezing of supercooled H2SO4/H2O solution droplets was investigated in the aerosol chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere of Forschungszentrum Karlsruhe. 24 freezing experiments were performed at temperatures between 194 and 235 K with aerosol particles in the diameter range 0.05 to 1 µm. Individual experiments started at homogeneous temperatures and ice saturation ratios between 0.85 and 0.95. Cloud cooling rates up to -2.8 K/min were simulated dynamically in the chamber by expansion cooling using a mechanical pump. Depending on the cooling rate and starting temperature, freezing threshold relative humidities were exceeded after expansion time periods between about 1 and 10 min. The onset of ice formation was measured with three independent methods showing good agreement among each other. Ice saturation ratios measured at the onset of ice formation increased from about 1.4 at 231 K to about 1.75 at 189 K. The experimental data set including thermodynamic parameters as well as physical and chemical aerosol analysis provides a good basis for microphysical model applications.

  14. Modeling global impacts of heterogeneous loss of HO2 on cloud droplets, ice particles and aerosols

    Directory of Open Access Journals (Sweden)

    V. Huijnen

    2014-03-01

    Full Text Available The abundance and spatial variability of the hydroperoxyl radical (HO2 in the troposphere strongly affects atmospheric composition through tropospheric ozone production and associated HOx chemistry. One of the largest uncertainties in the chemical HO2 budget is its heterogeneous loss on the surface of cloud droplets, ice particles and aerosols. We quantify the importance of the heterogeneous HO2 loss at global scale using the latest recommendations on the scavenging efficiency on various surfaces. For this we included the simultaneous loss on cloud droplets and ice particles as well as aerosol in the Composition-Integrated Forecast System (C-IFS. We show that cloud surface area density (SAD is typically an order of magnitude larger than aerosol SAD, using assimilated satellite retrievals to constrain both meteorology and global aerosol distributions. Depending on the assumed uptake coefficients, loss on liquid water droplets and ice particles accounts for ∼53–70% of the total heterogeneous loss of HO2, due to the ubiquitous presence of cloud droplets. This indicates that HO2 uptake on cloud should be included in chemistry transport models that already include uptake on aerosol. Our simulations suggest that the zonal mean mixing ratios of HO2 are reduced by ∼25% in the tropics and up to ∼50% elsewhere. The subsequent decrease in oxidative capacity leads to a global increase of the tropospheric carbon monoxide (CO burden of up to 7%, and an increase in the ozone tropospheric lifetime of ∼6%. This increase results in an improvement in the global distribution when compared against CO surface observations over the Northern Hemisphere, although it does not fully resolve the wintertime bias in the C-IFS. There is a simultaneous increase in the high bias in C-IFS for tropospheric CO over the Southern Hemisphere, which constrains on the assumptions regarding HO2 uptake on a global scale. We show that enhanced HO2 uptake on aerosol types

  15. The effect of particle acidity on secondary organic aerosol formation from α-pinene photooxidation under atmospherically relevant conditions

    Science.gov (United States)

    Han, Yuemei; Stroud, Craig A.; Liggio, John; Li, Shao-Meng

    2016-11-01

    Secondary organic aerosol (SOA) formation from photooxidation of α-pinene has been investigated in a photochemical reaction chamber under varied inorganic seed particle acidity levels at moderate relative humidity. The effect of particle acidity on SOA yield and chemical composition was examined under high- and low-NOx conditions. The SOA yield (4.2-7.6 %) increased nearly linearly with the increase in particle acidity under high-NOx conditions. In contrast, the SOA yield (28.6-36.3 %) was substantially higher under low-NOx conditions, but its dependency on particle acidity was insignificant. A relatively strong increase in SOA yield (up to 220 %) was observed in the first hour of α-pinene photooxidation under high-NOx conditions, suggesting that SOA formation was more effective for early α-pinene oxidation products in the presence of fresh acidic particles. The SOA yield decreased gradually with the increase in organic mass in the initial stage (approximately 0-1 h) under high-NOx conditions, which is likely due to the inaccessibility to the acidity over time with the coating of α-pinene SOA, assuming a slow particle-phase diffusion of organic molecules into the inorganic seeds. The formation of later-generation SOA was enhanced by particle acidity even under low-NOx conditions when introducing acidic seed particles after α-pinene photooxidation, suggesting a different acidity effect exists for α-pinene SOA derived from later oxidation stages. This effect could be important in the atmosphere under conditions where α-pinene oxidation products in the gas-phase originating in forested areas (with low NOx and SOx) are transported to regions abundant in acidic aerosols such as power plant plumes or urban regions. The fraction of oxygen-containing organic fragments (CxHyO1+ 33-35 % and CxHyO2+ 16-17 %) in the total organics and the O / C ratio (0.52-0.56) of α-pinene SOA were lower under high-NOx conditions than those under low-NOx conditions (39-40, 17-19, and

  16. Measurement, growth types and shrinkage of newly formed aerosol particles at an urban research platform

    Science.gov (United States)

    Salma, Imre; Németh, Zoltán; Weidinger, Tamás; Kovács, Boldizsár; Kristóf, Gergely

    2016-06-01

    Budapest platform for Aerosol Research and Training (BpART) was created for advancing long-term on-line atmospheric measurements and intensive aerosol sample collection campaigns in Budapest. A joint study including atmospheric chemistry or physics, meteorology, and fluid dynamics on several-year-long data sets obtained at the platform confirmed that the location represents a well-mixed, average atmospheric environment for the city centre. The air streamlines indicated that the host and neighbouring buildings together with the natural orography play an important role in the near-field dispersion processes. Details and features of the airflow structure were derived, and they can be readily utilised for further interpretations. An experimental method to determine particle diffusion losses in the differential mobility particle sizer (DMPS) system of the BpART facility was proposed. It is based on CPC-CPC (condensation particle counter) and DMPS-CPC comparisons. Growth types of nucleated particles observed in 4 years of measurements were presented and discussed specifically for cities. Arch-shaped size distribution surface plots consisting of a growth phase followed by a shrinkage phase were characterised separately since they supply information on nucleated particles. They were observed in 4.5 % of quantifiable nucleation events. The shrinkage phase took 1 h 34 min in general, and the mean shrinkage rate with standard deviation was -3.8 ± 1.0 nm h-1. The shrinkage of particles was mostly linked to changes in local atmospheric conditions, especially in global radiation and the gas-phase H2SO4 concentration through its proxy, or to atmospheric mixing in few cases. Some indirect results indicate that variations in the formation and growth rates of nucleated particles during their atmospheric transport could be a driving force of shrinkage for particles of very small sizes and on specific occasions.

  17. Organic functional groups in aerosol particles from burning and non-burning forest emissions at a high-elevation mountain site

    Directory of Open Access Journals (Sweden)

    S. Takahama

    2011-07-01

    Full Text Available Ambient particles collected on teflon filters at the Peak of Whistler Mountain, British Columbia (2182 m a.s.l. during spring and summer 2009 were measured by Fourier transform infrared (FTIR spectroscopy for organic functional groups (OFG. The project mean and standard deviation of organic aerosol mass concentrations (OM for all samples was 3.2±3.3 (μg m−3. Measurements of aerosol mass fragments, size, and number concentrations were used to separate fossil-fuel combustion and burning and non-burning forest sources of the measured organic aerosol. The OM was composed of the same anthropogenic and non-burning forest components observed at Whistler mid-valley in the spring of 2008; during the 2009 campaign, biomass burning aerosol was additionally observed from fire episodes occurring between June and September. On average, organic hydroxyl, alkane, carboxylic acid, ketone, and primary amine groups represented 31 %±11 %, 34 %±9 %, 23 %±6 %, 6 %±7 %, and 6 %±3 % of OM, respectively. Ketones in aerosols were associated with burning and non-burning forest origins, and represented up to 27 % of the OM. The organic aerosol fraction resided almost entirely in the submicron fraction without significant diurnal variations. OM/OC mass ratios ranged mostly between 2.0 and 2.2 and O/C atomic ratios between 0.57 and 0.76, indicating that the organic aerosol reaching the site was highly aged and possibly formed through secondary formation processes.

  18. Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

    Directory of Open Access Journals (Sweden)

    J.-M. Diesch

    2012-04-01

    Full Text Available Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W. As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM1 was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS. Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2 and a weather station provided meteorological parameters.

    Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m−3 and 1000 cm−3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54% was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of

  19. Attenuated total reflectance FT-IR imaging and quantitative energy dispersive-electron probe X-ray microanalysis techniques for single particle analysis of atmospheric aerosol particles.

    Science.gov (United States)

    Ryu, JiYeon; Ro, Chul-Un

    2009-08-15

    This work demonstrates the practical applicability of the combined use of attenuated total reflectance (ATR) FT-IR imaging and low-Z particle electron probe X-ray microanalysis (EPMA) techniques for the characterization of individual aerosol particles. These two single particle analytical techniques provide complementary information on the physicochemical characteristics of the same individual particles, that is, the low-Z particle EPMA for the information on the morphology and elemental concentration and the ATR-FT-IR imaging on the functional group, molecular species, and crystal structure. It was confirmed that the ATR-FT-IR imaging technique can provide sufficient FT-IR absorption signals to perform molecular speciation of individual particles of micrometer size when applied to artificially generated aerosol particles such as ascorbic acid and NaNO(3) aerosols. An exemplar indoor atmospheric aerosol sample was investigated to demonstrate the practical feasibility of the combined application of ATR-FT-IR imaging and low-Z particle EPMA techniques for the characterization of individual airborne particles.

  20. A Robust Computational Method for Coupled Liquid-liquid Phase Separation and Gas-particle Partitioning Predictions of Multicomponent Aerosols

    Science.gov (United States)

    Zuend, A.; Di Stefano, A.

    2014-12-01

    Providing efficient and reliable model predictions for the partitioning of atmospheric aerosol components between different phases (gas, liquids, solids) is a challenging problem. The partitioning of water, various semivolatile organic components, inorganic acids, bases, and salts, depends simultaneously on the chemical properties and interaction effects among all constituents of a gas + aerosol system. The effects of hygroscopic particle growth on the water contents and physical states of potentially two or more liquid and/or solid aerosol phases in turn may significantly affect multiphase chemistry, the direct effect of aerosols on climate, and the ability of specific particles to act as cloud condensation or ice nuclei. Considering the presence of a liquid-liquid phase separation in aerosol particles, which typically leads to one phase being enriched in rather hydrophobic compounds and the other phase enriched in water and dissolved electrolytes, adds a high degree of complexity to the goal of predicting the gas-particle partitioning of all components. Coupled gas-particle partitioning and phase separation methods are required to correctly account for the phase behaviour of aerosols exposed to varying environmental conditions, such as changes to relative humidity. We present new theoretical insights and a substantially improved algorithm for the reliable prediction of gas-particle partitioning at thermodynamic equilibrium based on the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model. We introduce a new approach for the accurate prediction of the phase distribution of multiple inorganic ions between two liquid phases, constrained by charge balance, and the coupling of the liquid-liquid equilibrium model to a robust gas-particle partitioning algorithm. Such coupled models are useful for exploring the range of environmental conditions leading to complete or incomplete miscibility of aerosol constituents which will affect

  1. Modeling the evolution of aerosol particles in a ship plume using PartMC-MOSAIC

    Science.gov (United States)

    Tian, J.; Riemer, N.; West, M.; Pfaffenberger, L.; Schlager, H.; Petzold, A.

    2014-06-01

    This study investigates the evolution of ship-emitted aerosol particles using the stochastic particle-resolved model PartMC-MOSAIC (Particle Monte Carlo model-Model for Simulating Aerosol Interactions and Chemistry). Comparisons of our results with observations from the QUANTIFY (Quantifying the Climate Impact of Global and European Transport Systems) study in 2007 in the English Channel and the Gulf of Biscay showed that the model was able to reproduce the observed evolution of total number concentration and the vanishing of the nucleation mode consisting of sulfate particles. Further process analysis revealed that during the first hour after emission, dilution reduced the total number concentration by four orders of magnitude, while coagulation reduced it by an additional order of magnitude. Neglecting coagulation resulted in an overprediction of more than one order of magnitude in the number concentration of particles smaller than 40 nm at a plume age of 100 s. Coagulation also significantly altered the mixing state of the particles, leading to a continuum of internal mixtures of sulfate and black carbon. The impact on cloud condensation nuclei (CCN) concentrations depended on the supersaturation threshold S at which CCN activity was evaluated. For the base case conditions, characterized by a low formation rate of secondary aerosol species, neglecting coagulation, but simulating condensation, led to an underestimation of CCN concentrations of about 37% for S = 0.3% at the end of the 14-h simulation. In contrast, for supersaturations higher than 0.7%, neglecting coagulation resulted in an overestimation of CCN concentration, about 75% for S = 1%. For S lower than 0.2% the differences between simulations including coagulation and neglecting coagulation were negligible. Neglecting condensation, but simulating coagulation did not impact the CCN concentrations below 0.2% and resulted in an underestimation of CCN concentrations for larger supersaturations, e.g., 18

  2. Evaluation of the particle measurement programme (PMP) protocol to remove the vehicles' exhaust aerosol volatile phase.

    Science.gov (United States)

    Giechaskiel, B; Chirico, R; Decarlo, P F; Clairotte, M; Adam, T; Martini, G; Heringa, M F; Richter, R; Prevot, A S H; Baltensperger, U; Astorga, C

    2010-10-01

    European regulation for Euro 5/6 light duty emissions introduced the measurement of non-volatile particles with diameter >23 nm. The volatile phase is removed by using a heated dilution stage (150 degrees C) and a heated tube (at 300-400 degrees C). We investigated experimentally the removal efficiency for volatile species of the specific protocol by conducting measurements with two Euro 3 diesel light duty vehicles, a Euro 2 moped, and a Euro III heavy duty vehicle with the system's heaters on and off. The particle number distributions were measured with a Scanning Mobility Particle Sizer (SMPS) and a Fast Mobility Particle Sizer (FMPS). An Aerosol Mass Spectrometer (AMS) was used to identify the non-refractory chemical composition of the particles. A Multi-Angle Absorption Photometer (MAAP) was used to measure the black carbon concentration. The results showed that the condensed material in the accumulation mode (defined here as particles in the diameter range of approximately 50-500 nm) was removed with an efficiency of 50-90%. The (volatile) nucleation mode was also completely evaporated or was decreased to sizes <23 nm; thus these particles wouldn't be counted from the particle counter, indicating the robustness of the protocol.

  3. Springtime precipitation effects on the abundance of fluorescent biological aerosol particles and HULIS in Beijing

    Science.gov (United States)

    Yue, Siyao; Ren, Hong; Fan, Songyun; Sun, Yele; Wang, Zifa; Fu, Pingqing

    2016-07-01

    Bioaerosols and humic-like substances (HULIS) are important components of atmospheric aerosols, which can affect regional climate by acting as cloud condensation nuclei and some of which can damage human health. Up to date, release of bioaerosols and HULIS initiated by precipitation is still poorly understood. Here we present different release processes for bioaerosols, non-bioaerosols and HULIS during a precipitation event in Beijing, China. Large fungal-spore-like aerosols were emitted at the onset and later weak stage of precipitation, the number concentration of which increased by more than two folds, while the number concentration of bacteria-like particles doubled when the precipitation strengthened. Besides, a good correlation between protein-like substances that were measured simultaneously by on-line and off-line fluorescence techniques consolidated their applications to measure bioaerosols. Furthermore, our EEM results suggest that the relative contribution of water-soluble HULIS to microbial materials was enhanced gradually by the rain event.

  4. Cloud Formation Potential of Biomass Burning Aerosol Surrogate-Particles Chemically Aged by OH

    Science.gov (United States)

    Slade, J. H.; Thalman, R. M.; Wang, J.; Li, Z. Q.; Knopf, D. A.

    2014-12-01

    Heterogeneous or multiphase reactions between trace gases such as OH and atmospheric aerosol can influence physicochemical properties of the particles including composition, morphology and lifetime. In this work, the cloud condensation nuclei (CCN) activity of laboratory-generated biomass burning aerosol (BBA) exposed to OH radicals is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type and OH exposure ([OH]×time) using a CCN counter coupled to a custom-built aerosol flow reactor (AFR). The composition of particles collected by a micro-orifice uniform deposit impactor (MOUDI) first subjected to different OH exposures is analyzed by Raman and scanning transmission X-ray microscopy coupled with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Levoglucosan (LEV), 4-methyl-5-nitrocatechol (MNC), and potassium sulfate (KS) serve as representative compounds found in BBA that have different hygroscopicity, chemical functionalities, and reactivity with OH radicals. BBA surrogate-particles are generated following atomization of aqueous solutions with mass ratios LEV:MNC:KS of 1:0:0, 0:1:0, 0:0:1, 1:1:0, 0:1:1, 1:0:1, 1:1:1, and 1:0.03:0.3. OH radicals are generated in the AFR following photolysis of O3 in the presence of H2O using a variable intensity ultra-violet (UV) lamp, which allows equivalent atmospheric OH exposures from days to weeks. In addition, we investigate how κ changes i) in response to varying [O3] with and without OH, and ii) at a fixed OH exposure while varying RH. The impact of OH exposure on the CCN activity of BBA will be presented and its atmospheric implications will be discussed.

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

    Science.gov (United States)

    Kawana, Kaori; Nakayama, Tomoki; Mochida, Michihiro

    2016-04-01

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

  6. Impact of interannual variations in aerosol particle sources on orographic precipitation over California's Central Sierra Nevada

    Science.gov (United States)

    Creamean, J. M.; Ault, A. P.; White, A. B.; Neiman, P. J.; Ralph, F. M.; Minnis, P.; Prather, K. A.

    2015-01-01

    Aerosols that serve as cloud condensation nuclei (CCN) and ice nuclei (IN) have the potential to profoundly influence precipitation processes. Furthermore, changes in orographic precipitation have broad implications for reservoir storage and flood risks. As part of the CalWater field campaign (2009-2011), the variability and associated impacts of different aerosol sources on precipitation were investigated in the California Sierra Nevada using an aerosol time-of-flight mass spectrometer for precipitation chemistry, S-band profiling radar for precipitation classification, remote sensing measurements of cloud properties, and surface meteorological measurements. The composition of insoluble residues in precipitation samples collected at a surface site contained mostly local biomass burning and long-range transported dust and biological particles (2009), local sources of biomass burning and pollution (2010), and long-range transport from distant sources (2011). Although differences in the sources were observed from year-to-year, the most consistent source of dust and biological residues were associated with storms consisting of deep convective cloud systems with significant quantities of precipitation initiated in the ice phase. Further, biological residues were dominant (up to 40%) during storms with relatively warm cloud temperatures (up to -15 °C), supporting the important role bioparticles can play as ice nucleating particles. On the other hand, lower percentages of residues from local biomass burning and pollution were observed over the three winter seasons (on average 31 and 9%, respectively). When precipitation quantities were relatively low, these residues most likely served as CCN, forming smaller more numerous cloud droplets at the base of shallow cloud systems, and resulting in less efficient riming processes. The correlation between the source of aerosols within clouds and precipitation type and quantity will be further probed in models to understand the

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

    Science.gov (United States)

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

    2013-11-01

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

  8. Effect of particle-fiber friction coefficient on ultrafine aerosol particles clogging in nanofiber based filter

    Science.gov (United States)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2013-04-01

    Realistic SEM image based 3D filter model considering transition/free molecular flow regime, Brownian diffusion, aerodynamic slip, particle-fiber and particle-particle interactions together with a novel Euclidian distance map based methodology for the pressure drop calculation has been utilized for a polyurethane nanofiber based filter prepared via electrospinning process in order to more deeply understand the effect of particle-fiber friction coefficient on filter clogging and basic filter characteristics. Based on the performed theoretical analysis, it has been revealed that the increase in the fiber-particle friction coefficient causes, firstly, more weaker particle penetration in the filter, creation of dense top layers and generation of higher pressure drop (surface filtration) in comparison with lower particle-fiber friction coefficient filter for which deeper particle penetration takes place (depth filtration), secondly, higher filtration efficiency, thirdly, higher quality factor and finally, higher quality factor sensitivity to the increased collected particle mass. Moreover, it has been revealed that even if the particle-fiber friction coefficient is different, the cake morphology is very similar.

  9. Criteria for significance of simultaneous presence of both condensible vapors and aerosol particles on mass transfer (deposition) rates

    Science.gov (United States)

    Gokoglu, S. A.

    1987-01-01

    The simultaneous presence of aerosol particles and condensible vapors in a saturated boundary layer which may affect deposition rates to subcooled surfaces because of vapor-particle interactions is discussed. Scavenging of condensible vapors by aerosol particles may lead to increased particle size and decreased vapor mass fraction, which alters both vapor and particle deposition rates. Particles, if sufficiently concentrated, may also coagulate. Criteria are provided to assess the significance of such phenomena when particles are already present in the mainstream and are not created inside the boundary layer via homogeneous nucleation. It is determined that there is direct proportionality with: (1) the mass concentration of both condensible vapors and aerosol particles; and (2) the square of the boundary layer thickness to particle diameter ratio (delta d sub p) square. Inverse proportionality was found for mainstream to surface temperature difference if thermophoresis dominates particle transport. It is concluded that the square of the boundary layer thickness to particle diameter ratio is the most critical factor to consider in deciding when to neglect vapor-particle interactions.

  10. The interaction between air ions and aerosol particles in the atmosphere

    CERN Document Server

    Aplin, KL

    2012-01-01

    Charged particles are continually generated in atmospheric air, and the interaction between natural ionisation and atmospheric particles is complicated. It is of some climatic importance to establish if ions are implicated in particle formation. Atmospheric ion concentrations have been investigated here at high temporal resolution, using Gerdien ion analysers at a site where synchronous meteorological measurements were also made. The background ionisation rate was also monitored with a Geiger counter, enabling ion production from natural radioactivity to be distinguished from other effects. Measurements at 1Hz offer some promise in establishing the atmospheric electrical influences in ionic nucleation bursts, although combinations of other meteorological factors are also known to be significant. High time resolution meteorological and ion measurements are therefore clearly necessary in advancing basic understanding in the behaviour of atmospheric aerosol.

  11. Possible effect of extreme solar energetic particle event of 20 January 2005 on polar stratospheric aerosols: direct observational evidence

    Directory of Open Access Journals (Sweden)

    I. A. Mironova

    2012-01-01

    Full Text Available Energetic cosmic rays are the main source of ionization of the low-middle atmosphere, leading to associated changes in atmospheric properties. Via the hypothetical influence of ionization on aerosol growth and facilitated formation of clouds, this may be an important indirect link relating solar variability to climate. This effect is highly debated, however, since the proposed theoretical mechanisms still remain illusive and qualitative, and observational evidence is inconclusive and controversial. Therefore, important questions regarding the existence and magnitude of the effect, and particularly the fraction of aerosol particles that can form and grow, are still open. Here we present empirical evidence of the possible effect caused by cosmic rays upon polar stratospheric aerosols, based on a case study of an extreme solar energetic particle (SEP event of 20 January 2005. Using aerosol data obtained over polar regions from different satellites with optical instruments that were operating during January 2005, such as the Stratospheric Aerosol and Gas Experiment III (SAGE III, and Optical Spectrograph and Infrared Imaging System (OSIRIS, we found a significant simultaneous change in aerosol properties in both the Southern and Northern Polar regions in temporal association with the SEP event. We speculate that ionization of the atmosphere, which was abnormally high in the lower stratosphere during the extreme SEP event, might have led to formation of new particles and/or growth of preexisting ultrafine particles in the polar stratospheric region. However, a detailed interpretation of the effect is left for subsequent studies. This is the first time high vertical resolution measurements have been used to discuss possible production of stratospheric aerosols under the influence of cosmic ray induced ionization. The observed effect is marginally detectable for the analyzed severe SEP event and can be undetectable for the majority of weak

  12. Treatment of losses of ultrafine aerosol particles in long sampling tubes during ambient measurements

    Science.gov (United States)

    Kumar, Prashant; Fennell, Paul; Symonds, Jonathan; Britter, Rex

    Long sampling tubes are often required for particle measurements in street canyons. This may lead to significant losses of the number of ultrafine (those below 100 nm) particles within the sampling tubes. Inappropriate treatment of these losses may significantly change the measured particle number distributions (PND), because most of the ambient particles, by number, exist in the ultrafine size range. Based on the Reynolds number (Re) in the sampling tubes, most studies treat the particle losses using the Gormley and Kennedy laminar flow model (Gormley, P.G., Kennedy, M., 1949. Diffusion from a stream following through a cylinderical tube. Proceedings of Royal Irish Academy 52, 163-169.) or the Wells and Chamberlain turbulent flow model (Wells, A.C., Chamberlain, A.C., 1967. Transport of small particles to vertical surfaces. British Journal of Applied Physics 18, 1793-1799.). Our experiments used a particle spectrometer with various lengths (1.00, 5.47, 5.55, 8.90 and 13.40 m) of sampling tube to measure the PNDs in the 5-2738 nm range. Experiments were performed under different operating conditions to measure the particle losses through silicone rubber tubes of circular cross-section (7.85 mm internal diameter). Sources of particles included emissions from an idling diesel engine car in a street canyon, emissions from a burning candle and those from the generation of salt aerosols using a nebuliser in the laboratory. Results showed that losses for particles below ≈20 nm were important and were largest for the smallest size range (5-10 nm), but were modest for particles above ≈20 nm. In our experiments the laminar flow model did not reflect the observations for small Re. This may be due to the sampling tubes not being kept straight or other complications. In situ calibration or comparison appears to be required.

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

    Science.gov (United States)

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

    2015-12-01

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

  14. Possible effect of extreme solar energetic particle events of September–October 1989 on polar stratospheric aerosols: a case study

    Directory of Open Access Journals (Sweden)

    I. A. Mironova

    2013-09-01

    Full Text Available The main ionization source of the middle and low Earth's atmosphere is related to energetic particles coming from outer space. Usually it is ionization from cosmic rays that is always present in the atmosphere. But in a case of a very strong solar eruption, some solar energetic particles (SEPs can reach middle/low atmosphere increasing the ionization rate up to some orders of magnitude at polar latitudes. We continue investigating such a special class of solar events and their possible applications for natural variations of the aerosol content. After the case study of the extreme SEP event of January 2005 and its possible effect upon polar stratospheric aerosols, here we analyze atmospheric applications of the sequence of several events that took place over autumn 1989. Using aerosol data obtained over polar regions from two satellites with space-borne optical instruments SAGE II and SAM II that were operating during September–October 1989, we found that an extreme major SEP event might have led to formation of new particles and/or growth of preexisting ultrafine particles in the polar stratospheric region. However, the effect of the additional ambient air ionization on the aerosol formation is minor, in comparison with temperature effect, and can take place only in the cold polar atmospheric conditions. The extra aerosol mass formed under the temperature effect allows attributing most of the changes to the "ion–aerosol clear sky mechanism".

  15. Particle deposition in a child respiratory tract model: in vivo regional deposition of fine and ultrafine aerosols in baboons.

    Science.gov (United States)

    Albuquerque-Silva, Iolanda; Vecellio, Laurent; Durand, Marc; Avet, John; Le Pennec, Déborah; de Monte, Michèle; Montharu, Jérôme; Diot, Patrice; Cottier, Michèle; Dubois, Francis; Pourchez, Jérémie

    2014-01-01

    To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region) of radioactive polydisperse aerosols ([d16-d84], equal to [0.15 µm-0.5 µm], [0.25 µm-1 µm], or [1 µm-9 µm]). Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm-9 µm] aerosol (72% ± 17%). The [0.15 µm-0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84% ± 4%). Airborne particles in the range of [0.25 µm-1 µm] showed an intermediate deposition pattern, with 49% ± 8% in the extrathoracic region and 51% ± 8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm-9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes.

  16. Particle deposition in a child respiratory tract model: in vivo regional deposition of fine and ultrafine aerosols in baboons.

    Directory of Open Access Journals (Sweden)

    Iolanda Albuquerque-Silva

    Full Text Available To relate exposure to adverse health effects, it is necessary to know where particles in the submicron range deposit in the respiratory tract. The possibly higher vulnerability of children requires specific inhalation studies. However, radio-aerosol deposition experiments involving children are rare because of ethical restrictions related to radiation exposure. Thus, an in vivo study was conducted using three baboons as a child respiratory tract model to assess regional deposition patterns (thoracic region vs. extrathoracic region of radioactive polydisperse aerosols ([d16-d84], equal to [0.15 µm-0.5 µm], [0.25 µm-1 µm], or [1 µm-9 µm]. Results clearly demonstrated that aerosol deposition within the thoracic region and the extrathoraic region varied substantially according to particle size. High deposition in the extrathoracic region was observed for the [1 µm-9 µm] aerosol (72% ± 17%. The [0.15 µm-0.5 µm] aerosol was associated almost exclusively with thoracic region deposition (84% ± 4%. Airborne particles in the range of [0.25 µm-1 µm] showed an intermediate deposition pattern, with 49% ± 8% in the extrathoracic region and 51% ± 8% in the thoracic region. Finally, comparison of baboon and human inhalation experiments for the [1 µm-9 µm] aerosol showed similar regional deposition, leading to the conclusion that regional deposition is species-independent for this airborne particle sizes.

  17. Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    J. D. Allan

    2006-01-01

    Full Text Available The study of the growth of nucleation-mode particles is important, as this prevents their loss through diffusion and allows them to reach sizes where they may become effective cloud condensation nuclei. Hyytiälä, a forested site in southern Finland, frequently experiences particle nucleation events during the spring and autumn, where particles first appear during the morning and continue to grow for several hours afterwards. As part of the QUEST 2 intensive field campaign during March and April 2003, an Aerodyne Aerosol Mass Spectrometer (AMS was deployed alongside other aerosol instrumentation to study the particulate composition and dynamics of growth events and characterise the background aerosol. Despite the small mass concentrations, the AMS was able to distinguish the grown particles in the <100 nm regime several hours after an event and confirm that the particles were principally organic in composition. The AMS was also able to derive a mass spectral fingerprint for the organic species present, and found that it was consistent between events and independent of the mean particle diameter during non-polluted cases, implying the same species were also condensing onto the accumulation mode. The results were compared with those from offline analyses such as GC-MS and were consistent with the hypothesis that the main components were alkanes from plant waxes and the oxidation products of terpenes.

  18. Impacts of aerosol particles on the microphysical and radiative properties of stratocumulus clouds over the southeast Pacific Ocean

    Science.gov (United States)

    Twohy, C. H.; Anderson, J. R.; Toohey, D. W.; Andrejczuk, M.; Adams, A.; Lytle, M.; George, R. C.; Wood, R.; Saide, P.; Spak, S.; Zuidema, P.; Leon, D.

    2013-03-01

    The southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles on the stratocumulus deck was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, droplets were collected and evaporated using a counterflow virtual impactor (CVI), and the non-volatile residual particles were analyzed. Many flights focused on the gradient in cloud properties on an E-W track along 20° S from near the Chilean coast to remote areas offshore. Mean statistics, including their significance, from eight flights and many individual legs were compiled. Consistent with a continental source of cloud condensation nuclei, below-cloud accumulation-mode aerosol and droplet number concentration generally decreased from near shore to offshore. Single particle analysis was used to reveal types and sources of the enhanced particle number that influence droplet concentration. While a variety of particle types were found throughout the region, the dominant particles near shore were partially neutralized sulfates. Modeling and chemical analysis indicated that the predominant source of these particles in the marine boundary layer along 20° S was anthropogenic pollution from central Chilean sources, with copper smelters a relatively small contribution. Cloud droplets were smaller in regions of enhanced particles near shore. However, physically thinner clouds, and not just higher droplet number concentrations from pollution, both contributed to the smaller droplets. Satellite measurements were used to show that cloud albedo was highest 500-1000 km offshore, and actually slightly lower closer to shore due to the generally thinner clouds and lower liquid water paths

  19. Molecular-scale evidence of aerosol particle formation via sequential addition of HIO3

    Science.gov (United States)

    Sipilä, Mikko; Sarnela, Nina; Jokinen, Tuija; Henschel, Henning; Junninen, Heikki; Kontkanen, Jenni; Richters, Stefanie; Kangasluoma, Juha; Franchin, Alessandro; Peräkylä, Otso; Rissanen, Matti P.; Ehn, Mikael; Vehkamäki, Hanna; Kurten, Theo; Berndt, Torsten; Petäjä, Tuukka; Worsnop, Douglas; Ceburnis, Darius; Kerminen, Veli-Matti; Kulmala, Markku; O'Dowd, Colin

    2016-09-01

    Homogeneous nucleation and subsequent cluster growth leads to the formation of new aerosol particles in the atmosphere. The nucleation of sulfuric acid and organic vapours is thought to be responsible for the formation of new particles over continents, whereas iodine oxide vapours have been implicated in particle formation over coastal regions. The molecular clustering pathways that are involved in atmospheric particle formation have been elucidated in controlled laboratory studies of chemically simple systems, but direct molecular-level observations of nucleation in atmospheric field conditions that involve sulfuric acid, organic or iodine oxide vapours have yet to be reported. Here we present field data from Mace Head, Ireland, and supporting data from northern Greenland and Queen Maud Land, Antarctica, that enable us to identify the molecular steps involved in new particle formation in an iodine-rich, coastal atmospheric environment. We find that the formation and initial growth process is almost exclusively driven by iodine oxoacids and iodine oxide vapours, with average oxygen-to-iodine ratios of 2.4 found in the clusters. On the basis of this high ratio, together with the high concentrations of iodic acid (HIO3) observed, we suggest that cluster formation primarily proceeds by sequential addition of HIO3, followed by intracluster restructuring to I2O5 and recycling of water either in the atmosphere or on dehydration. Our study provides ambient atmospheric molecular-level observations of nucleation, supporting the previously suggested role of iodine-containing species in the formation of new aerosol particles, and identifies the key nucleating compound.

  20. Molecular-scale evidence of aerosol particle formation via sequential addition of HIO3.

    Science.gov (United States)

    Sipilä, Mikko; Sarnela, Nina; Jokinen, Tuija; Henschel, Henning; Junninen, Heikki; Kontkanen, Jenni; Richters, Stefanie; Kangasluoma, Juha; Franchin, Alessandro; Peräkylä, Otso; Rissanen, Matti P; Ehn, Mikael; Vehkamäki, Hanna; Kurten, Theo; Berndt, Torsten; Petäjä, Tuukka; Worsnop, Douglas; Ceburnis, Darius; Kerminen, Veli-Matti; Kulmala, Markku; O'Dowd, Colin

    2016-09-22

    Homogeneous nucleation and subsequent cluster growth leads to the formation of new aerosol particles in the atmosphere. The nucleation of sulfuric acid and organic vapours is thought to be responsible for the formation of new particles over continents, whereas iodine oxide vapours have been implicated in particle formation over coastal regions. The molecular clustering pathways that are involved in atmospheric particle formation have been elucidated in controlled laboratory studies of chemically simple systems, but direct molecular-level observations of nucleation in atmospheric field conditions that involve sulfuric acid, organic or iodine oxide vapours have yet to be reported. Here we present field data from Mace Head, Ireland, and supporting data from northern Greenland and Queen Maud Land, Antarctica, that enable us to identify the molecular steps involved in new particle formation in an iodine-rich, coastal atmospheric environment. We find that the formation and initial growth process is almost exclusively driven by iodine oxoacids and iodine oxide vapours, with average oxygen-to-iodine ratios of 2.4 found in the clusters. On the basis of this high ratio, together with the high concentrations of iodic acid (HIO3) observed, we suggest that cluster formation primarily proceeds by sequential addition of HIO3, followed by intracluster restructuring to I2O5 and recycling of water either in the atmosphere or on dehydration. Our study provides ambient atmospheric molecular-level observations of nucleation, supporting the previously suggested role of iodine-containing species in the formation of new aerosol particles, and identifies the key nucleating compound.

  1. CURRENT AND EMERGING TECHNIQUES FOR CHARACTERIZING TROPOSPHERIC AEROSOLS

    Science.gov (United States)

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

  2. 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)

  3. LOAC: a small aerosol optical counter/sizer for ground-based and balloon measurements of the size distribution and nature of atmospheric particles - Part 1: Principle of measurements and instrument evaluation

    Science.gov (United States)

    Renard, J.-B.; Dulac, F.; Berthet, G.; Lurton, T.; Vignelles, D.; Jégou, F.; Tonnelier, T.; Thaury, C.; Jeannot, M.; Couté, B.; Akiki, R.; Verdier, N.; Mallet, M.; Gensdarmes, F.; Charpentier, P.; Duverger, V.; Dupont, J.-C.; Mesmin, S.; Elias, T.; Crenn, V.; Sciare, J.; Giacomoni, J.; Gobbi, M.; Hamonou, E.; Olafsson, H.; Dagsson-Waldhauserova, P.; Camy-Peyret, C.; Mazel, C.; Décamps, T.; Piringer, M.; Surcin, J.; Daugeron, D.

    2015-09-01

    The study of aerosols in the troposphere and in the stratosphere is of major importance both for climate and air quality studies. Among the numerous instruments available, aerosol particles counters provide the size distribution in diameter range from few hundreds of nm to few tens of μm. Most of them are very sensitive to the nature of aerosols, and this can result in significant biases in the retrieved size distribution. We describe here a new versatile optical particle/sizer counter (OPC) named LOAC (Light Optical Aerosol Counter), which is light and compact enough to perform measurements not only at the surface but under all kinds of balloons in the troposphere and in the stratosphere. LOAC is an original OPC performing observations at two scattering angles. The first one is around 12°, and is almost insensitive to the nature of the particles; the second one is around 60° and is strongly sensitive to the refractive index of the particles. By combining measurement at the two angles, it is possible to retrieve accurately the size distribution and to estimate the nature of the dominant particles (droplets, carbonaceous, salts and mineral particles) in several size classes. This topology is based on calibration charts obtained in the laboratory. Several campaigns of cross-comparison of LOAC with other particle counting instruments and remote sensing photometers have been conducted to validate both the size distribution derived by LOAC and the retrieved particle number density. The topology of the aerosols has been validated in well-defined conditions including urban pollution, desert dust episodes, fog, and cloud. Comparison with reference aerosol mass monitoring instruments also shows that the LOAC measurements can be successfully converted to mass concentrations. All these tests indicate that no bias is present in the LOAC measurements and in the corresponding data processing.

  4. LOAC: a small aerosol optical counter/sizer for ground-based and balloon measurements of the size distribution and nature of atmospheric particles – Part 1: Principle of measurements and instrument evaluation

    Directory of Open Access Journals (Sweden)

    J.-B. Renard

    2015-01-01

    Full Text Available The study of aerosols in the troposphere and in the stratosphere is of major importance both for climate and air quality studies. Among the numerous instruments available, aerosol particles counters provide the size distribution in diameter range from few hundreds of nm to few tens of μm. Most of them are very sensitive to the nature of aerosols, and this can result in significant biases in the retrieved size distribution. We describe here a new versatile optical particle/sizer counter (OPC named LOAC (Light Optical Aerosols Counter, which is light and compact enough to perform measurements not only at the surface but under all kinds of balloons in the troposphere and in the stratosphere. LOAC is an original OPC performing observations at two scattering angles. The first one is around 12°, and is almost insensitive to the nature of the particles; the second one is around 60° and is strongly sensitive to the refractive index of the particles. By combining measurement at the two angles, it is possible to retrieve accurately the size distribution and to estimate the nature of the dominant particles (droplets, carbonaceous, salts and mineral particles in several size classes. This speciation is based on calibration charts obtained in the laboratory. Several campaigns of cross-comparison of LOAC with other particle counting instruments and remote sensing photometers have been conducted to validate both the size distribution derived by LOAC and the retrieved particle number density. The speciation of the aerosols has been validated in well-defined conditions including urban pollution, desert dust episodes, fog, and cloud. Comparison with reference aerosol mass monitoring instruments also shows that the LOAC measurements can be successfully converted to mass concentrations. All these tests indicate that no bias is present in the LOAC measurements and in the corresponding data processing.

  5. MADE-in: a new aerosol microphysics submodel for global simulation of insoluble particles and their mixing state

    Directory of Open Access Journals (Sweden)

    V. Aquila

    2011-04-01

    Full Text Available Black carbon (BC and mineral dust are among the most abundant insoluble aerosol components in the atmosphere. When released, most BC and dust particles are externally mixed with other aerosol species. Through coagulation with particles containing soluble material and condensation of gases, the externally mixed particles may obtain a liquid coating and be transferred into an internal mixture. The mixing state of BC and dust aerosol particles influences their radiative and hygroscopic properties, as well as their ability of forming ice crystals.

    We introduce the new aerosol microphysics submodel MADE-in, implemented within the ECHAM/MESSy Atmospheric Chemistry global model (EMAC. MADE-in is able to track mass and number concentrations of BC and dust particles in their different mixing states, as well as particles free of BC and dust. MADE-in describes these three classes of particles through a superposition of seven log-normally distributed modes, and predicts the evolution of their size distribution and chemical composition. Six out of the seven modes are mutually interacting, allowing for the transfer of mass and number among them. Separate modes for the different mixing states of BC and dust particles in EMAC/MADE-in allow for explicit simulations of the relevant aging processes, i.e. condensation, coagulation and cloud processing. EMAC/MADE-in has been evaluated with surface and airborne measurements and mostly performs well both in the planetary boundary layer and in the upper troposphere and lowermost stratosphere.

  6. Characterization of Particle Size Distributions of Powdery Building Material Aerosol Generated by Fluidization and Gravitation

    Directory of Open Access Journals (Sweden)

    Tadas Prasauskas

    2012-10-01

    Full Text Available This study aims to identify particle size distributions (PSD of aerosol of powdery building materials commonly used in construction work (cement, chalk, clay, wood sawdust, wood grinding dust, gypsum, hydrated lime, masonry grout, quartz sand, sand and structural lime by two aerosolization methods: fluidization and gravitation. Fluidization and gravitation methods represent industrial activities such as pneumotransportation and unloading. Both particle resuspension mechanisms have been modelled in laboratory conditions. The particle size distributions of resuspended particulate matter from powdery building materials were rather similar identified by both fluidization and gravitation methods, with an exception of wood sawdust and sand. The PM10 fraction ranged between 30% and 87%, PM2.5 from 7% to 28% and PM1.0 from 3% to 7% of the total mass of particulate matter. The highest PM10/PMtotal ratio was calculated for masonry grout - 0.87, and the lowest ratio for quartz sand - 0.30. The highest ratio of PM2.5/PMtotal was calculated for sand - 0.23, the lowest for quartz sand - 0.07. Substantial quantities of PM2.5 were found to be emitted implying a potential threat to human health.DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1519

  7. On the composition of ammonia-sulfuric acid clusters during aerosol particle formation

    CERN Document Server

    Schobesberger, S; Bianchi, F; Rondo, L; Duplissy, J; Kürten, A; Ortega, I K; Metzger, A; Schnitzhofer, R; Almeida, J; Amorim, A; Dommen, J; Dunne, E M; Ehn, M; Gagné, S; Ickes, L; Junninen, H; Hansel, A; Kerminen, V-M; Kirkby, J; Kupc, A; Laaksonen, A; Lehtipalo, K; Mathot, S; Onnela, A; Petäjä, T; Riccobono, F; Santos, F D; Sipilä, M; Tomé, A; Tsagkogeorgas, G; Viisanen, Y; Wagner, P E; Wimmer, D; Curtius, J; Donahue, N M; Baltensperger, U; Kulmala, M; Worsnop, D R

    2014-01-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small NH3-H2SO4 clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm / Δn = 1.05 and were only observed at sufficiently high [NH3] / [H2SO4]. The H2SO4 molecules of these clusters are partially neutralized by NH3, in close resemblance to the acid-base bindings ...

  8. Determining aerosol particles by in-air micro-IL analysis combined with micro-PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada.wataru@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2013-07-01

    A new external ion microbeam ion luminescence (micro-IL) imaging system was developed on a microbeam line of a 3 MV single-ended accelerator at the TIARA facility of the Japan Atomic Energy Agency. Micro-IL was combined with an in-air micro-PIXE (particle-induced X-ray emission) system to determine the chemical composition and structures of microscopic airborne particles of several micrometers in size. The hardware and software for the combined in-air micro-IL analysis system, called ion luminescence microscopic imaging and spectroscopy (ILUMIS), were studied. Wavelength-dispersive optics, including a collimator lens, a monochromator, and a photon-counting photomultiplier, were installed on the beam line. The signal processing of the IL photon signals, which were collected as spectra and two-dimensional microscopic images, was examined. Several aerosol particles were characterized to demonstrate the ILUMIS/PIXE combined analysis. The external microbeam ILUMIS analysis method provided a variety of information on the chemical and elemental composition of the micrometer-sized aerosol targets under ambient atmospheric conditions.

  9. Hygrosopicity measurements of aerosol particles in the San Joaquin Valley, CA, Baltimore, MD, and Golden, CO

    Science.gov (United States)

    Orozco, Daniel; Beyersdorf, A. J.; Ziemba, L. D.; Berkoff, T.; Zhang, Q.; Delgado, R.; Hennigan, C. J.; Thornhill, K. L.; Young, D. E.; Parworth, C.; Kim, H.; Hoff, R. M.

    2016-06-01

    Aerosol hygroscopicity was investigated using a novel dryer-humidifier system, coupled to a TSI-3563 nephelometer, to obtain the light scattering coefficient (σscat) as a function of relative humidity (RH) in hydration and dehydration modes. The measurements were performed in Porterville, CA (10 January to 6 February 2013), Baltimore, MD (3-30 July 2013), and Golden, CO (12 July to 10 August 2014). Observations in Porterville and Golden were part of the NASA-sponsored Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality project. The measured σscat under varying RH in the three sites was combined with ground aerosol extinction, PM2.5 mass concentrations, and particle composition measurements and compared with airborne observations performed during campaigns. The enhancement factor, f(RH), defined as the ratio of σscat(RH) at a certain RH divided by σscat at a dry value, was used to evaluate the aerosol hygroscopicity. Particles in Porterville showed low average f(RH = 80%) (1.42) which was attributed to the high carbonaceous loading in the region where residential biomass burning and traffic emissions contribute heavily to air pollution. In Baltimore, the high average f(RH = 80%) (2.06) was attributed to the large contribution of SO42- in the region. The lowest water uptake was observed in Golden, with an average f(RH = 80%) = 1.24 where organic carbon dominated the particle loading. Different empirical fits were evaluated using the f(RH) data. The widely used Kasten (gamma) model was found least satisfactory, as it overestimates f(RH) for RH < 75%. A better empirical fit with two power law curve fitting parameters c and k was found to replicate f(RH) accurately from the three sites. The relationship between the organic carbon mass and the species that are affected by RH and f(RH) was also studied and categorized.

  10. Individual aerosol particles in and below clouds along a Mt. Fuji slope: Modification of sea-salt-containing particles by in-cloud processing

    Science.gov (United States)

    Ueda, S.; Hirose, Y.; Miura, K.; Okochi, H.

    2014-02-01

    Sizes and compositions of atmospheric aerosol particles can be altered by in-cloud processing by absorption/adsorption of gaseous and particulate materials and drying of aerosol particles that were formerly activated as cloud condensation nuclei. To elucidate differences of aerosol particles before and after in-cloud processing, aerosols were observed along a slope of Mt. Fuji, Japan (3776 m a.s.l.) during the summer in 2011 and 2012 using a portable laser particle counter (LPC) and an aerosol sampler. Aerosol samples for analyses of elemental compositions were obtained using a cascade impactor at top-of-cloud, in-cloud, and below-cloud altitudes. To investigate composition changes via in-cloud processing, individual particles (0.5-2 μm diameter) of samples from five cases (days) collected at different altitudes under similar backward air mass trajectory conditions were analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. For most cases (four cases), most particles at all altitudes mainly comprised sea salts: mainly Na with some S and/or Cl. Of those, in two cases, sea-salt-containing particles with Cl were found in below-cloud samples, although sea-salt-containing particles in top-of-cloud samples did not contain Cl. This result suggests that Cl in the sea salt was displaced by other cloud components. In the other two cases, sea-salt-containing particles on samples at all altitudes were without Cl. However, molar ratios of S to Na (S/Na) of the sea-salt-containing particles of top-of-cloud samples were higher than those of below-cloud samples, suggesting that sulfuric acid or sulfate was added to sea-salt-containing particles after complete displacement of Cl by absorption of SO2 or coagulation with sulfate. The additional volume of sulfuric acid in clouds for the two cases was estimated using the observed S/Na values of sea-salt-containing particles. The estimation revealed that size changes by in

  11. Chemical Composition of Aerosol Particles Emitted by a Passenger Car Engine Fueled by Ethanol/Gasoline Mixtures

    Science.gov (United States)

    Medrano, J. M.; Gross, D. S.; Dutcher, D. D.; Drayton, M.; Kittelson, D.; McMurry, P.

    2007-12-01

    With concerns of national security, climate change, and human health, many people have called for oil independence for the United States and for the creation of alternative fuels. Ethanol has been widely praised as a viable alternative to petroleum-based fuels, due to the fact that it can be produced locally. A great deal of work has been done to characterize the energy balance of ethanol production versus consumption, but there have been fewer studies of the environmental and health impacts of emissions from combustion of ethanol/gasoline mixtures such as those burned in the modern vehicle fleet. To study the particulate emissions from such fuels, different ethanol/gasoline fuel mixtures with 0, 20, 40, and 85% ethanol were burned in a dynamometer-mounted automobile engine. The engine exhaust was diluted and sampled with two aerosol Time-of-Flight Mass Spectrometers (TSI 3800 ATOFMS), sampling different particle size ranges (50-500 nm and 150-3000 nm, respectively), to measure size and composition of the emitted aerosol particles. A variety of other aerosol characterization techniques were also employed to determine the size distribution of the aerosol particles, the mass emission rate from the engine, and the concentration of polycyclic aromatic hydrocarbons (PAHs) and elemental carbon (EC) in the particle emissions. Here we will focus on results from the ATOFMS, which provides us with a particle size and mass spectra - for both negative and positive ions - for each particle that is sampled. Particles being emitted were found to contain primarily PAHs, elemental carbon (EC), nitrates, and sulfates. Particles were analyzed to investigate trends in particle composition as a function of fuel ethanol content, particle size, and for the types of particles emitted. A trend in particle type as a function of fuel ethanol content was evident in smaller particles, and trends in composition as a function of particle size were visible across the entire size range sampled.

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

    Science.gov (United States)

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

    2008-01-01

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

  13. 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).

  14. Quantitative energy-dispersive electron probe X-ray microanalysis for single-particle analysis and its application for characterizing atmospheric aerosol particles

    Indian Academy of Sciences (India)

    Shila Maskey; Chul-Un Ro

    2011-02-01

    An energy-dispersive electron probe X-ray microanalysis (ED-EPMA) technique using an energy-dispersive X-ray detector with an ultra-thin window, designated as low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements such as C, N and O, as well as higher-Z elements that can be analysed by conventional ED-EPMA. The quantitative determination of low-Z elements (using full Monte Carlo simulations, from the electron impact to the X-ray detection) in individual particles has improved the applicability of single-particle analysis, especially in atmospheric environmental aerosol research; many environmentally important atmospheric particles, e.g. sulphates, nitrates, ammonium and carbonaceous particles, contain low-Z elements. To demonstrate its practical applicability, the application of the low-Z particle EPMA for the characterization of Asian Dust, urban and subway aerosol particles is shown herein. In addition, it is demonstrated that the Monte Carlo calculation can also be applied in a quantitative single-particle analysis using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectrometry (EDX), showing that the technique is useful and reliable for the characterization of submicron aerosol particles

  15. Measurement of the deposition of aerosol particles to skin, hair and clothing

    CERN Document Server

    Bell, K F

    1998-01-01

    efficient. range 1.3 -15x10 sup - sup 3 ms sup - sup 1 were recorded, values which are approximately an order of magnitude higher than the equivalent values onto the floor of the test room. These values suggest that the exposure route of radioactive aerosol particles deposited on the skin may be more significant than hitherto had been assumed. The possible mechanisms leading to this relatively high deposition were investigated experimentally and the results suggested that a combination of factors such as the body's electrostatic field, surface temperature and surface roughness were contributors. A wind tunnel was used to carry out experiments to compare the deposition velocities of a 1.4 mu m mean diameter aerosol onto human body phantoms in a simulated outdoor environment with the values from the test chamber experiments. The measured aerosol deposition velocities were found to vary with wind velocity; values in the range 6.8 - 11x10 sup - sup 3 ms sup - sup 1 were recorded. The clearance of deposited aeroso...

  16. Aerosol dynamics using the quadrature method of moments: comparing several quadrature schemes with particle-resolved simulation

    Energy Technology Data Exchange (ETDEWEB)

    McGraw, R [Environmental Sciences Department, Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Leng, L; Zhu, W [Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY 11794-3600 (United States); Riemer, N [Atmospheric Sciences Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3070 (United States); West, M [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3070 (United States)], E-mail: rlm@bnl.gov

    2008-07-15

    The method of moments (MOM) is a statistically based alternative to sectional and modal methods for aerosol simulation. The MOM is highly efficient as the aerosol distribution is represented by its lower-order moments and only these, not the full distribution itself, are tracked during simulation. Quadrature is introduced to close the moment equations under very general growth laws and to compute aerosol physical and optical properties directly from moments. In this paper the quadrature method of moments (QMOM) is used in a bivariate test tracking of aerosol mixing state. Two aerosol populations, one enriched in soot and the other in sulfate, are allowed to interact through coagulation to form a generally-mixed third particle population. Quadratures of varying complexity (including two candidate schemes for use in climate models) are described and compared with benchmark results obtained by using particle-resolved simulation. Low-order quadratures are found to be highly accurate, and Gauss and Gauss-Radau quadratures appear to give nested lower and upper bounds, respectively, to aerosol mixing rate. These results suggest that the QMOM makes it feasible to represent the generallymixed states of aerosols and track their evolution in climate models.

  17. Simulating Marine New Particle Formation and Growth Using the M7 Modal Aerosol Dynamics Modal

    Directory of Open Access Journals (Sweden)

    Ciaran Monahan

    2010-01-01

    Full Text Available A modal atmospheric aerosol model (M7 is evaluated in terms of predicting marine new particle formation and growth. Simulations were carried out for three different nucleation schemes involving (1 kinetic self-nucleation of OIO (2 nucleation via OIO activation by H2SO4 and (3 nucleation via OIO activation by H2SO4 plus condensation of a low-volatility organic vapour. Peak OIO and H2SO4 vapour concentrations were both limited to 6×106 molecules cm-3 at noontime while the peak organic vapour concentration was limited to 12×106 molecules cm-3. All simulations produced significant concentrations of new particles in the Aitken mode. From a base case particle concentration of 222 cm-3 at radii >15 nm, increases in concentrations to 366 cm-3 were predicted from the OIO-OIO case, 722 cm-3 for the OIO-H2SO4 case, and 1584 cm-3 for the OIO-H2SO4 case with additional condensing organic vapours. The results indicate that open ocean new particle production is feasible for clean conditions; however, new particle production becomes most significant when an additional condensable organic vapour is available to grow the newly formed particles to larger sizes. Comparison to sectional model for a typical case study demonstrated good agreement and the validity of using the modal model.

  18. Modeling aerosol surface chemistry and gas-particle interaction kinetics with K2-SURF: PAH oxidation

    Science.gov (United States)

    Shiraiwa, M.; Garland, R.; Pöschl, U.

    2009-04-01

    Atmospheric aerosols are ubiquitous in the atmosphere. They have the ability to impact cloud properties, radiative balance and provide surfaces for heterogeneous reactions. The uptake of gaseous species on aerosol surfaces impacts both the aerosol particles and the atmospheric budget of trace gases. These subsequent changes to the aerosol can in turn impact the aerosol chemical and physical properties. However, this uptake, as well as the impact on the aerosol, is not fully understood. This uncertainty is due not only to limited measurement data, but also a dearth of comprehensive and applicable modeling formalizations used for the analysis, interpretation and description of these heterogeneous processes. Without a common model framework, comparing and extrapolating experimental data is difficult. In this study, a novel kinetic surface model (K2-SURF) [Ammann & Pöschl, 2007; Pöschl et al., 2007] was used to describe the oxidation of a variety of polycyclic aromatic hydrocarbons (PAHs). Integrated into this consistent and universally applicable kinetic and thermodynamic process model are the concepts, terminologies and mathematical formalizations essential to the description of atmospherically relevant physicochemical processes involving organic and mixed organic-inorganic aerosols. Within this process model framework, a detailed master mechanism, simplified mechanism and parameterizations of atmospheric aerosol chemistry are being developed and integrated in analogy to existing mechanisms and parameterizations of atmospheric gas-phase chemistry. One of the key aspects to this model is the defining of a clear distinction between various layers of the particle and surrounding gas phase. The processes occurring at each layer can be fully described using known fluxes and kinetic parameters. Using this system there is a clear separation of gas phase, gas-surface and surface bulk transport and reactions. The partitioning of compounds can be calculated using the flux

  19. Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

    Science.gov (United States)

    Vergara-Temprado, Jesús; Murray, Benjamin J.; Wilson, Theodore W.; O'Sullivan, Daniel; Browse, Jo; Pringle, Kirsty J.; Ardon-Dryer, Karin; Bertram, Allan K.; Burrows, Susannah M.; Ceburnis, Darius; DeMott, Paul J.; Mason, Ryan H.; O'Dowd, Colin D.; Rinaldi, Matteo; Carslaw, Ken S.

    2017-03-01

    Ice-nucleating particles (INPs) are known to affect the amount of ice in mixed-phase clouds, thereby influencing many of their properties. The atmospheric INP concentration changes by orders of magnitude from terrestrial to marine environments, which typically contain much lower concentrations. Many modelling studies use parameterizations for heterogeneous ice nucleation and cloud ice processes that do not account for this difference because they were developed based on INP measurements made predominantly in terrestrial environments without considering the aerosol composition. Errors in the assumed INP concentration will influence the simulated amount of ice in mixed-phase clouds, leading to errors in top-of-atmosphere radiative flux and ultimately the climate sensitivity of the model. Here we develop a global model of INP concentrations relevant for mixed-phase clouds based on laboratory and field measurements of ice nucleation by K-feldspar (an ice-active component of desert dust) and marine organic aerosols (from sea spray). The simulated global distribution of INP concentrations based on these two species agrees much better with currently available ambient measurements than when INP concentrations are assumed to depend only on temperature or particle size. Underestimation of INP concentrations in some terrestrial locations may be due to the neglect of INPs from other terrestrial sources. Our model indicates that, on a monthly average basis, desert dusts dominate the contribution to the INP population over much of the world, but marine organics become increasingly important over remote oceans and they dominate over the Southern Ocean. However, day-to-day variability is important. Because desert dust aerosol tends to be sporadic, marine organic aerosols dominate the INP population on many days per month over much of the mid- and high-latitude Northern Hemisphere. This study advances our understanding of which aerosol species need to be included in order to

  20. Spectral Light Absorption and Scattering by Aerosol Particles in Central Amazonia

    Science.gov (United States)

    Artaxo, P.; Holanda, B. A.; Ferreira De Brito, J.; Carbone, S.; Barbosa, H. M.; Rizzo, L. V.; Cirino, G. G.; Andreae, M. O.; Saturno, J.; Pöhlker, C.; Martin, S. T.; Holben, B. N.; Schafer, J.

    2015-12-01

    As part of the GoAmazon2014/5, a detailed characterization of spectral light absorption and light scattering was performed at four research sites located in the central Amazon forest at different distances upwind and downwind of Manaus. The sites ATTO (T0a) and Embrapa (T0e) are located upwind of Manaus where it is possible to observe very pristine atmospheric conditions in wet season. The site Tiwa (T2) is being operated under the direct influence of the Manaus plume at 5 km downwind of Manaus and, finally, the Manacapuru (T3) site is located at about 60 km downwind of Manaus. The spectral dependence of light absorption and light scattering were measured using Aethalometers (7-wavelengths) and Nephelometers (3-wavelengths), respectively. By calculating the Absorption Angstrom Exponent (AAE), it was possible to get information about the source of the aerosol whereas the Scattering Angstrom Exponent (SAE) gives information about its size distribution. Sunphotometers from the AERONET network were set up at T3 and T0e sites to measure column Aerosol Optical Depth (AOD). For all the stations, much higher absorption and scattering coefficients were observed during the dry season in comparison to the wet season, as a result of the larger concentration of BC and OC present in the biomass burning events. Additionally, we also observed Manaus plume pollution that alters the BC signal. There is also an increase of the AAE during the dry season due to the larger amount of aerosols from biomass burning compared with urban pollution. High values of AAE are also observed during the wet season, attributed to the presence of long-range transport of aerosols from Africa. The SAE for all the sites are lower during the wet season, with the dominance of large biological particles, and increases during the dry season as a consequence of fine particles emitted from both biomass and fossil fuel burning. The AOD at T0e and T3 (Jan-Jun/2014) showed very similar values ranging from 0.05 to

  1. Seasonality of ultrafine and sub-micron aerosols and the inferences on particle formation processes

    Science.gov (United States)

    Cheung, H. C.; Chou, C. C.-K.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Lee, C. S.-L.

    2015-08-01

    The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultrafine particles (UFPs, d ≤ 100nm) and submicron particles (PM1, d ≤ 1 μm) in an East-Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at the TARO, an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC) and size distribution (PSD) with size range of 4-736 nm. The results indicate that the mass concentration of PM1 was elevated during cold seasons with peak level of 18.5 μg m-3 in spring, whereas the highest UFPs concentration was measured in summertime with a seasonal mean of 1.62 μg m-3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents in PM1. The seasonal median of total PNCs ranged from 13.9 × 103 cm-3 in autumn to 19.4 × 103 cm-3 in spring. The PSD information retrieved from the corresponding PNC measurements indicates that the nucleation mode PNC (N4-25) peaked at 11.6 × 103 cm-3 in winter, whereas the Aitken mode (N25-100) and accumulation mode (N100-736) exhibited summer maxima at 6.0 × 103 and 3.1 × 103 cm-3, respectively. The shift in PSD during summertime is attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributes to the growth of aerosol particles in the atmosphere. In addition, remarkable photochemical production of particles was observed in spring and summer seasons, which was characterized with averaged particle growth and formation rates of 4.3 ± 0.8 nm h-1 and 1.6 ± 0.8 cm-3 s-1, respectively. The prevalence of new particle formation (NPF) in summer is

  2. On the Origin of AMS "Cooking Organic Aerosol" at a Rural Site.

    Science.gov (United States)

    Dall'Osto, M; Paglione, M; Decesari, S; Facchini, M C; O'Dowd, C; Plass-Duellmer, Christian; Harrison, Roy M

    2015-12-15

    A number of field observations employing aerosol mass spectrometers (AMS) have demonstrated that organic matter rich in monocarboxylic acids and aliphatic carbonyls originating from cooking activities (the COA factor) contributes significantly to ambient organic matter (OM) in urban environments. Little is known about the contribution and nature of COA in rural localities. We studied the correlation of COA with chemical tracers at a rural site in the Po Valley, Italy. Our statistical approach, based on positive matrix factorization (PMF) shows that the COA factor was clearly linked to local emissions of chloride and methanesulfonic acid (MSA), chemical tracers not associated with cooking emissions, or with combustion sources. While the association with Cl is not understood at this stage, the emission of reduced sulfur compounds, aliphatic carbonyls and monocarboxylic acids is consistent with several agricultural practices (e.g., manure storage) and waste disposal systems (e.g., landfills) which characterize the suburban and rural areas of the Po Valley and of other many populated environments. It is concluded that the nature and origins of the AMS COA factor measured at a rural site are complex and include far more than the emissions from food cooking.

  3. Secondary organic aerosol origin in an urban environment: influence of biogenic and fuel combustion precursors.

    Science.gov (United States)

    Minguillón, M C; Pérez, N; Marchand, N; Bertrand, A; Temime-Roussel, B; Agrios, K; Szidat, S; van Drooge, B; Sylvestre, A; Alastuey, A; Reche, C; Ripoll, A; Marco, E; Grimalt, J O; Querol, X

    2016-07-18

    Source contributions of organic aerosol (OA) are still not fully understood, especially in terms of quantitative distinction between secondary OA formed from anthropogenic precursors vs. that formed from natural precursors. In order to investigate the OA origin, a field campaign was carried out in Barcelona in summer 2013, including two periods characterized by low and high traffic conditions. Volatile organic compound (VOC) concentrations were higher during the second period, especially aromatic hydrocarbons related to traffic emissions, which showed a marked daily cycle peaking during traffic rush hours, similarly to black carbon (BC) concentrations. Biogenic VOC (BVOC) concentrations showed only minor changes from the low to the high traffic period, and their intra-day variability was related to temperature and solar radiation cycles, although a decrease was observed for monoterpenes during the day. The organic carbon (OC) concentrations increased from the first to the second period, and the fraction of non-fossil OC as determined by (14)C analysis increased from 43% to 54% of the total OC. The combination of (14)C analysis and Aerosol Chemical Speciation Monitor (ACSM) OA source apportionment showed that the fossil OC was mainly secondary (>70%) except for the last sample, when the fossil secondary OC only represented 51% of the total fossil OC. The fraction of non-fossil secondary OC increased from 37% of total secondary OC for the first sample to 60% for the last sample. This enhanced formation of non-fossil secondary OA (SOA) could be attributed to the reaction of BVOC precursors with NOx emitted from road traffic (or from its nocturnal derivative nitrate that enhances night-time semi-volatile oxygenated OA (SV-OOA)), since NO2 concentrations increased from 19 to 42 μg m(-3) from the first to the last sample.

  4. Online laser desorption-multiphoton postionization mass spectrometry of individual aerosol particles: molecular source indicators for particles emitted from different traffic-related and wood combustion sources.

    Science.gov (United States)

    Bente, Matthias; Sklorz, Martin; Streibel, Thorsten; Zimmermann, Ralf

    2008-12-01

    Direct inlet aerosol mass spectrometry plays an increasingly important role in applied and fundamental aerosol and nanoparticle research. Laser desorption/ionization (LDI) based techniques for single particle time-of-flight mass spectrometry (LDI-SP-TOFMS) are a promising approach in the chemical analysis of single aerosol particles, especially for the detection of inorganic species and distinction of particle classes. However, until now the detection of molecular organic compounds on a single particle basis has been difficult due to the high laser power densities which are required for the LDI process as well as due to the inherent matrix effects associated with this ionization technique. By the application of a two-step approach, where an IR desorption laser pulse is applied to perform a gentle desorption of organic material from the single particle surface and a second UV-laser performs the soft ionization of the desorbed species, this drawback of laser based single particles mass spectrometry can be overcome. The postionization of the desorbed molecules has been accomplished in this work by resonance enhanced multiphoton ionization (REMPI) using a KrF excimer laser (248 nm). REMPI allows an almost fragmentation free trace analysis of polycyclic aromatic hydrocarbons (PAHs) and their derivatives from individual single particles (laser desorption-REMPI postionization-single particle-time-of-flight mass spectrometry or LD-REMPI-SP-TOFMS). Crucial system parameters of the home-built aerosol mass spectrometer such as the power densities and the relative timing of both lasers were optimized with respect to the detectability of particle source specific organic signatures using well characterized standard particles. In a second step, the LD-REMPI-SP-TOFMS system was applied to analyze different real world aerosols (spruce wood combustion, gasoline car exhaust, beech wood combustion, and diesel car exhaust). It was possible to distinguish the particles from different

  5. Size distributions and temporal variations of biological aerosol particles in the Amazon rainforest characterized by microscopy and real-time UV-APS fluorescence techniques during AMAZE-08

    Directory of Open Access Journals (Sweden)

    J. A. Huffman

    2012-12-01

    Full Text Available As a part of the AMAZE-08 campaign during the wet season in the rainforest of central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS was operated for continuous measurements of fluorescent biological aerosol particles (FBAP. In the coarse particle size range (> 1 μm the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m−3 (4.0–13.2 × 104 m−3 and 0.72 μg m−3 (0.42–1.19 μg m−3, respectively, accounting for 24% (11–41% of total particle number and 47% (25–65% of total particle mass. During the five-week campaign in February–March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM, light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no true fungal staining. This mode may have consisted of single bacterial cells, brochosomes, various fragments of biological material, and small Chromalveolata (Chromista spores. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF techniques using 355 nm excitation provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles in a pristine

  6. Size distributions and temporal variations of biological aerosol particles in the Amazon rainforest characterized by microscopy and real-time UV-APS fluorescence techniques during AMAZE-08

    Science.gov (United States)

    Huffman, J. A.; Sinha, B.; Garland, R. M.; Snee-Pollmann, A.; Gunthe, S. S.; Artaxo, P.; Martin, S. T.; Andreae, M. O.; Pöschl, U.

    2012-12-01

    As a part of the AMAZE-08 campaign during the wet season in the rainforest of central Amazonia, an ultraviolet aerodynamic particle sizer (UV-APS) was operated for continuous measurements of fluorescent biological aerosol particles (FBAP). In the coarse particle size range (> 1 μm) the campaign median and quartiles of FBAP number and mass concentration were 7.3 × 104 m-3 (4.0-13.2 × 104 m-3) and 0.72 μg m-3 (0.42-1.19 μg m-3), respectively, accounting for 24% (11-41%) of total particle number and 47% (25-65%) of total particle mass. During the five-week campaign in February-March 2008 the concentration of coarse-mode Saharan dust particles was highly variable. In contrast, FBAP concentrations remained fairly constant over the course of weeks and had a consistent daily pattern, peaking several hours before sunrise, suggesting observed FBAP was dominated by nocturnal spore emission. This conclusion was supported by the consistent FBAP number size distribution peaking at 2.3 μm, also attributed to fungal spores and mixed biological particles by scanning electron microscopy (SEM), light microscopy and biochemical staining. A second primary biological aerosol particle (PBAP) mode between 0.5 and 1.0 μm was also observed by SEM, but exhibited little fluorescence and no true fungal staining. This mode may have consisted of single bacterial cells, brochosomes, various fragments of biological material, and small Chromalveolata (Chromista) spores. Particles liquid-coated with mixed organic-inorganic material constituted a large fraction of observations, and these coatings contained salts likely from primary biological origin. We provide key support for the suggestion that real-time laser-induce fluorescence (LIF) techniques using 355 nm excitation provide size-resolved concentrations of FBAP as a lower limit for the atmospheric abundance of biological particles in a pristine environment. We also show some limitations of using the instrument for ambient monitoring of

  7. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2008-08-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were made in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area-2006 campaign (MCMA-2006. Results are presented for the period of 15–27 March 2006. The submicron size mode contained both fresh and aged biomass burning, aged organic carbon (OC mixed with nitrate and sulfate, elemental carbon (EC, nitrogen-organic carbon, industrial metal, and inorganic NaK inorganic particles. Overall, biomass burning and aged OC particle types comprised 40% and 31%, respectively, of the submicron mode. In contrast, the supermicron mode was dominated by inorganic NaK particle types (42% which represented a mixture of dry lake bed dust and industrial NaK emissions mixed with soot. Additionally, aluminosilicate dust, transition metals, OC, and biomass burning contributed to the supermicron particles. Early morning periods (2–6 a.m. showed high fractions of inorganic particles from industrial sources in the northeast, composed of internal mixtures of Pb, Zn, EC and Cl, representing up to 73% of the particles in the 0.2–3μm size range. A unique nitrogen-containing organic carbon (NOC particle type, peaking in the early morning hours, was hypothesized to be amines from local industrial emissions based on the time series profile and back trajectory analysis. A strong dependence on wind speed and direction was observed in the single particle types that were present during different times of the day. The early morning (3:30–10 a.m. showed the greatest contributions from industrial emissions. During mid to late mornings (7–11 a.m., weak northerly winds were observed along with the most highly aged particles. Stronger winds from the south picked up in the late morning (after 11 a.m., resulting in a decrease in the concentrations of the major aged particle types and an increase in the number fraction of fresh

  8. Aerosol particle size distributions in the lower Fraser Valley: evidence for particle nucleation and growth

    Directory of Open Access Journals (Sweden)

    M. Mozurkewich

    2004-01-01

    Full Text Available Particle size distributions from 9 to 640nm diameter were measured at Eagle Ridge in the lower Fraser Valley from 13 August to 1 September 2001 as part of the Pacific 2001 Air Quality Study. The site was on top of a ridge, about 300m above the valley floor, in a predominantly agricultural area about 70km ESE of Vancouver. To further characterize the particles, their hygroscopic properties (affinity for water were measured. The maximum of the number distributions was generally between 40 and 100nm diameter, but the number distribution was sometimes dominated by ultrafine particles with diameters below 40nm. These ultrafine particles, which appeared to some extent on all days, were frequently associated with elevated levels of CO and NOx, as expected for fresh vehicular emissions. The appearance of these fresh emissions was most pronounced when the growing mixed layer reached the altitude of the site. In contrast, pronounced nucleation events occurred on the five cleanest days; these resulted in particle number concentrations as high as 5x104 particles cm-3 and growth rates of 5 to 10nmhr-1. Nucleation appears to have been triggered when the UV flux reached about 25Wm-2. The growth of these newly formed particles was probably driven by the photochemical oxidation of biogenic organic compounds. Dramatic growth events were also observed on the afternoons of the more polluted days; these produced an extremely narrow mode σ<0.3 at a diameter of about 40nm. Rainy days showed low number concentrations with the size distributions shifted to small sizes. On one of these days there was evidence of nucleation not far from the site; this may have been occurring in the vicinity of the clouds.

  9. Observations of the spectral dependence of linear particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar

    Science.gov (United States)

    Burton, S. P.; Hair, J. W.; Kahnert, M.; Ferrare, R. A.; Hostetler, C. A.; Cook, A. L.; Harper, D. B.; Berkoff, T. A.; Seaman, S. T.; Collins, J. E.; Fenn, M. A.; Rogers, R. R.

    2015-12-01

    Linear particle depolarization ratio is presented for three case studies from the NASA Langley airborne High Spectral Resolution Lidar-2 HSRL-2). Particle depolarization ratio from lidar is an indicator of non-spherical particles and is sensitive to the fraction of non-spherical particles and their size. The HSRL-2 instrument measures depolarization at three wavelengths: 355, 532, and 1064 nm. The three measurement cases presented here include two cases of dust-dominated aerosol and one case of smoke aerosol. These cases have partial analogs in earlier HSRL-1 depolarization measurements at 532 and 1064 nm and in literature, but the availability of three wavelengths gives additional insight into different scenarios for non-spherical particles in the atmosphere. A case of transported Saharan dust has a spectral dependence with a peak of 0.30 at 532 nm with smaller particle depolarization ratios of 0.27 and 0.25 at 1064 and 355 nm, respectively. A case of aerosol containing locally generated wind-blown North American dust has a maximum of 0.38 at 1064 nm, decreasing to 0.37 and 0.24 at 532 and 355 nm, respectively. The cause of the maximum at 1064 nm is inferred to be very large particles that have not settled out of the dust layer. The smoke layer has the opposite spectral dependence, with the peak of 0.24 at 355 nm, decreasing to 0.09 and 0.02 at 532 and 1064 nm, respectively. The depolarization in the smoke case may be explained by the presence of coated soot aggregates. We note that in these specific case studies, the linear particle depolarization ratio for smoke and dust-dominated aerosol are more similar at 355 nm than at 532 nm, having possible implications for using the particle depolarization ratio at a single wavelength for aerosol typing.

  10. Aerosol effective density measurement using scanning mobility particle sizer and quartz crystal microbalance with the estimation of involved uncertainty

    Science.gov (United States)

    Sarangi, Bighnaraj; Aggarwal, Shankar G.; Sinha, Deepak; Gupta, Prabhat K.

    2016-03-01

    In this work, we have used a scanning mobility particle sizer (SMPS) and a quartz crystal microbalance (QCM) to estimate the effective density of aerosol particles. This approach is tested for aerosolized particles generated from the solution of standard materials of known density, i.e. ammonium sulfate (AS), ammonium nitrate (AN) and sodium chloride (SC), and also applied for ambient measurement in New Delhi. We also discuss uncertainty involved in the measurement. In this method, dried particles are introduced in to a differential mobility analyser (DMA), where size segregation is done based on particle electrical mobility. Downstream of the DMA, the aerosol stream is subdivided into two parts. One is sent to a condensation particle counter (CPC) to measure particle number concentration, whereas the other one is sent to the QCM to measure the particle mass concentration simultaneously. Based on particle volume derived from size distribution data of the SMPS and mass concentration data obtained from the QCM, the mean effective density (ρeff) with uncertainty of inorganic salt particles (for particle count mean diameter (CMD) over a size range 10-478 nm), i.e. AS, SC and AN, is estimated to be 1.76 ± 0.24, 2.08 ± 0.19 and 1.69 ± 0.28 g cm-3, values which are comparable with the material density (ρ) values, 1.77, 2.17 and 1.72 g cm-3, respectively. Using this technique, the percentage contribution of error in the measurement of effective density is calculated to be in the range of 9-17 %. Among the individual uncertainty components, repeatability of particle mass obtained by the QCM, the QCM crystal frequency, CPC counting efficiency, and the equivalence of CPC- and QCM-derived volume are the major contributors to the expanded uncertainty (at k = 2) in comparison to other components, e.g. diffusion correction, charge correction, etc. Effective density for ambient particles at the beginning of the winter period in New Delhi was measured to be 1.28 ± 0.12 g cm-3

  11. Aerosol effective density measurement using scanning mobility particle sizer and quartz crystal microbalance with the estimation of involved uncertainty

    Directory of Open Access Journals (Sweden)

    B. Sarangi

    2015-12-01

    Full Text Available In this work, we have used scanning mobility particle sizer (SMPS and quartz crystal microbalance (QCM to estimate the effective density of aerosol particles. This approach is tested for aerosolized particles generated from the solution of standard materials of known density, i.e. ammonium sulfate (AS, ammonium nitrate (AN and sodium chloride (SC, and also applied for ambient measurement in New Delhi. We also discuss uncertainty involved in the measurement. In this method, dried particles are introduced in to a differential mobility analyzer (DMA, where size segregation was done based on particle electrical mobility. At the downstream of DMA, the aerosol stream is subdivided into two parts. One is sent to a condensation particle counter (CPC to measure particle number concentration, whereas other one is sent to QCM to measure the particle mass concentration simultaneously. Based on particle volume derived from size distribution data of SMPS and mass concentration data obtained from QCM, the mean effective density (ρeff with uncertainty of inorganic salt particles (for particle count mean diameter (CMD over a size range 10 to 478 nm, i.e. AS, SC and AN is estimated to be 1.76 ± 0.24, 2.08 ± 0.19 and 1.69 ± 0.28 g cm−3, which are comparable with the material density (ρ values, 1.77, 2.17 and 1.72 g cm−3, respectively. Among individual uncertainty components, repeatability of particle mass obtained by QCM, QCM crystal frequency, CPC counting efficiency, and equivalence of CPC and QCM derived volume are the major contributors to the expanded uncertainty (at k = 2 in comparison to other components, e.g. diffusion correction, charge correction, etc. Effective density for ambient particles at the beginning of winter period in New Delhi is measured to be 1.28 ± 0.12 g cm−3. It was found that in general, mid-day effective density of ambient aerosols increases with increase in CMD of particle size measurement but particle photochemistry is an

  12. A novel rocket-based in-situ collection technique for mesospheric and stratospheric aerosol particles

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    W. Reid

    2012-11-01

    Full Text Available A technique for collecting aerosol particles between altitudes of 85 and 17 km is described. Collection probes are ejected from a sounding rocket allowing for multi-point measurements. Each probe is equipped with 110 collection samples that are 3 mm in diameter. The collection samples are one of three types: standard transmission electron microscopy carbon grids, glass fibre filter paper or silicone gel. Each collection sample is exposed over a 50 m to 5 km height range with a total of 45 separate ranges. Post-flight electron microscopy gives size-resolved information on particle number, shape and elemental composition. Each collection probe is equipped with a suite of sensors to capture the probe's status during the fall. Parachute recovery systems along with GPS-based localization ensure that each probe can be located and recovered for post-flight analysis.

  13. An integrated approach using high time-resolved tools to study the origin of aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Di Gilio, A. [Chemistry Department, University of Bari, via Orabona, 4, 70126 Bari (Italy); ARPA PUGLIA, Corso Trieste, 27, 70126 Bari (Italy); Gennaro, G. de, E-mail: gianluigi.degennaro@uniba.it [Chemistry Department, University of Bari, via Orabona, 4, 70126 Bari (Italy); ARPA PUGLIA, Corso Trieste, 27, 70126 Bari (Italy); Dambruoso, P. [Chemistry Department, University of Bari, via Orabona, 4, 70126 Bari (Italy); ARPA PUGLIA, Corso Trieste, 27, 70126 Bari (Italy); Ventrella, G. [Chemistry Department, University of Bari, via Orabona, 4, 70126 Bari (Italy)

    2015-10-15

    Long-range transport of natural and/or anthropogenic particles can contribute significantly to PM10 and PM2.5 concentrations and some European cities often fail to comply with PM daily limit values due to the additional impact of particles from remote sources. For this reason, reliable methodologies to identify long-range transport (LRT) events would be useful to better understand air pollution phenomena and support proper decision-making. This study explores the potential of an integrated and high time-resolved monitoring approach for the identification and characterization of local, regional and long-range transport events of high PM. In particular, the goal of this work was also the identification of time-limited event. For this purpose, a high time-resolved monitoring campaign was carried out at an urban background site in Bari (southern Italy) for about 20 days (1st–20th October 2011). The integration of collected data as the hourly measurements of inorganic ions in PM{sub 2.5} and their gas precursors and of the natural radioactivity, in addition to the analyses of aerosol maps and hourly back trajectories (BT), provided useful information for the identification and chemical characterization of local sources and trans-boundary intrusions. Non-sea salt (nss) sulfate levels were found to increase when air masses came from northeastern Europe and higher dispersive conditions of the atmosphere were detected. Instead, higher nitrate and lower nss-sulfate concentrations were registered in correspondence with air mass stagnation and attributed to local traffic source. In some cases, combinations of local and trans-boundary sources were observed. Finally, statistical investigations such as the principal component analysis (PCA) applied on hourly ion concentrations and the cluster analyses, the Potential Source Contribution Function (PSCF) and the Concentration Weighted Trajectory (CWT) models computed on hourly back-trajectories enabled to complete a cognitive

  14. Heterogeneous OH oxidation of palmitic acid in single component and internally mixed aerosol particles: vaporization and the role of particle phase

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    C. B. Stipe

    2008-09-01

    Full Text Available We studied the OH oxidation of submicron aerosol particles consisting of pure palmitic acid (PA or thin (near monolayer coatings of PA on aqueous and effloresced inorganic salt particles. Experiments were performed as a function of particle size and OH exposure using a continuous-flow photochemical reaction chamber coupled to a chemical ionization mass spectrometer (CIMS system, for detection of gas and particle-bound organics, and a DMA/CPC for monitoring particle size distributions. The loss rate of PA observed for pure PA aerosols and PA on crystalline NaCl aerosols indicates that the OH oxidation of PA at the gas-aerosol interface is efficient. The pure PA oxidation data are well represented by a model consisting of four main processes: 1 surface-only reactions between OH and palmitic acid, 2 secondary reactions between palmitic acid and OH oxidation products, 3 volatilization of condensed-phase mass, and 4 a surface renewal process. Using this model we infer a value of γOH between 0.8 and 1. The oxidation of palmitic acid in thin film coatings of salt particles is also efficient, though the inferred γOH is lower, ranging from ~0.3+0.1/−0.05 for coatings on solid NaCl and ~0.05 (±0.01 on aqueous NaCl particles. These results, together with simultaneous data on particle size change and volatilized oxidation products, provide support for the ideas that oxidative aging of aliphatic organic aerosol is a source of small oxidized volatile organic compounds (OVOCs, and that OH oxidation may initiate secondary condensed-phase reactions.

  15. The heterogeneous OH oxidation of palmitic acid in single component and internally mixed aerosol particles: vaporization, secondary chemistry, and the role of particle phase

    Directory of Open Access Journals (Sweden)

    V. F. McNeill

    2008-03-01

    Full Text Available We studied the OH oxidation of submicron aerosol particles consisting of pure palmitic acid (PA or thin (near monolayer coatings of PA on aqueous and effloresced inorganic salt particles. Experiments were performed as a function of particle size and OH exposure using a continuous-flow photochemical reaction chamber coupled to a chemical ionization mass spectrometer (CIMS system, for detection of gas and particle-bound organics, and a DMA/CPC for monitoring particle size distributions. The loss rate of PA observed for pure PA aerosols and PA on crystalline NaCl aerosols indicates that the OH oxidation of PA at the gas-aerosol interface is efficient. The pure PA oxidation data are well represented by a model consisting of four main processes: 1 surface-only reactions between OH and palmitic acid, 2 secondary reactions between palmitic acid and OH oxidation products, 3 volatilization of condensed-phase mass, and 4 a surface renewal process. Using this model we infer a value of γOH between 0.8 and 1. The oxidation of palmitic acid in thin film coatings of salt particles is also efficient, though the inferred γOH is lower, ranging from ~0.3 (+0.1/−0.05 for coatings on solid NaCl and ~0.05 (±0.01 on aqueous NaCl particles. These results, together with simultaneous data on particle size change and volatilized oxidation products, provide support for the ideas that oxidative aging of aliphatic organic aerosol is a source of small oxidized volatile organic compounds (OVOCs, and that OH oxidation may initiate secondary condensed-phase reactions.

  16. Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation.

    Science.gov (United States)

    Grinshpun, Sergey A; Adhikari, Atin; Honda, Takeshi; Kim, Ki Youn; Toivola, Mika; Rao, K S Ramchander; Reponen, Tiina

    2007-01-15

    An indoor air purification technique, which combines unipolar ion emission and photocatalytic oxidation (promoted by a specially designed RCI cell), was investigated in two test chambers, 2.75 m3 and 24.3 m3, using nonbiological and biological challenge aerosols. The reduction in particle concentration was measured size selectively in real-time, and the Air Cleaning Factor and the Clean Air Delivery Rate (CADR) were determined. While testing with virions and bacteria, bioaerosol samples were collected and analyzed, and the microorganism survival rate was determined as a function of exposure time. We observed that the aerosol concentration decreased approximately 10 to approximately 100 times more rapidly when the purifier operated as compared to the natural decay. The data suggest that the tested portable unit operating in approximately 25 m3 non-ventilated room is capable to provide CADR-values more than twice as great than the conventional closed-loop HVAC system with a rating 8 filter. The particle removal occurred due to unipolar ion emission, while the inactivation of viable airborne microorganisms was associated with photocatalytic oxidation. Approximately 90% of initially viable MS2 viruses were inactivated resulting from 10 to 60 min exposure to the photocatalytic oxidation. Approximately 75% of viable B. subtilis spores were inactivated in 10 min, and about 90% or greater after 30 min. The biological and chemical mechanisms that led to the inactivation of stress-resistant airborne viruses and bacterial spores were reviewed.

  17. Applicability of the effective-medium approximation to heterogeneous aerosol particles

    Science.gov (United States)

    Mishchenko, Michael I.; Dlugach, Janna M.; Liu, Li

    2016-07-01

    The effective-medium approximation (EMA) is based on the assumption that a heterogeneous particle can have a homogeneous counterpart possessing similar scattering and absorption properties. We analyze the numerical accuracy of the EMA by comparing superposition T-matrix computations for spherical aerosol particles filled with numerous randomly distributed small inclusions and Lorenz-Mie computations based on the Maxwell-Garnett mixing rule. We verify numerically that the EMA can indeed be realized for inclusion size parameters smaller than a threshold value. The threshold size parameter depends on the refractive-index contrast between the host and inclusion materials and quite often does not exceed several tenths, especially in calculations of the scattering matrix and the absorption cross section. As the inclusion size parameter approaches the threshold value, the scattering-matrix errors of the EMA start to grow with increasing the host size parameter and/or the number of inclusions. We confirm, in particular, the existence of the effective-medium regime in the important case of dust aerosols with hematite or air-bubble inclusions, but then the large refractive-index contrast necessitates inclusion size parameters of the order of a few tenths. Irrespective of the highly restricted conditions of applicability of the EMA, our results provide further evidence that the effective-medium regime must be a direct corollary of the macroscopic Maxwell equations under specific assumptions.

  18. The Carbon Aerosol / Particles Nucleation with a Lidar: Numerical Simulations and Field Studies

    Science.gov (United States)

    Miffre, Alain; Anselmo, Christophe; Francis, Mirvatte; David, Gregory; Rairoux, Patrick

    2016-06-01

    In this contribution, we present the results of two recent papers [1,2] published in Optics Express, dedicated to the development of two new lidar methodologies. In [1], while the carbon aerosol (for example, soot particles) is recognized as a major uncertainty on climate and public health, we couple lidar remote sensing with Laser-Induced-Incandescence (LII) to allow retrieving the vertical profile of very low thermal radiation emitted by the carbon aerosol, in agreement with Planck's law, in an urban atmosphere over several hundred meters altitude. In paper [2], awarded as June 2014 OSA Spotlight, we identify the optical requirements ensuring an elastic lidar to be sensitive to new particles formation events (NPF-events) in the atmosphere, while, in the literature, all the ingredients initiating nucleation are still being unrevealed [3]. Both papers proceed with the same methodology by identifying the optical requirements from numerical simulation (Planck and Kirchhoff's laws in [1], Mie and T-matrix numerical codes in [2]), then presenting lidar field application case studies. We believe these new lidar methodologies may be useful for climate, geophysical, as well as fundamental purposes.

  19. Sugar markers in aerosol particles from an agro-industrial region in Brazil

    Science.gov (United States)

    Urban, R. C.; Alves, C. A.; Allen, A. G.; Cardoso, A. A.; Queiroz, M. E. C.; Campos, M. L. A. M.

    2014-06-01

    This work aimed to better understand how aerosol particles from sugar cane burning contribute to the chemical composition of the lower troposphere in an agro-industrial region of São Paulo State (Brazil) affected by sugar and ethanol fuel production. During a period of 21 months, we collected 105 samples and quantified 20 saccharides by GC-MS. The average concentrations of levoglucosan (L), mannosan (M), and galactosan (G) for 24-h sampling were 116, 16, and 11 ng m-3 respectively. The three anhydrosugars had higher and more variable concentrations in the nighttime and during the sugar cane harvest period, due to more intense biomass burning practices. The calculated L/M ratio, which may serve as a signature for sugar cane smoke particles, was 9 ± 5. Although the total concentrations of the anhydrosugars varied greatly among samples, the relative mass size distributions of the saccharides were reasonably constant. Emissions due to biomass burning were estimated to correspond to 69% (mass) of the sugars quantified in the harvest samples, whereas biogenic emissions corresponded to 10%. In the non-harvest period, these values were 44 and 27%, respectively, indicating that biomass burning is an important source of aerosol to the regional atmosphere during the whole year.

  20. Chemical closure study on hygroscopic properties of urban aerosol particles in Sapporo, Japan.

    Science.gov (United States)

    Aggarwal, Shankar Gopala; Mochida, Michihiro; Kitamori, Yasuyuki; Kawamura, Kimitaka

    2007-10-15

    To assess the link between hygroscopicity of atmospheric particles and the chemical composition, we performed a chemical closure study on the hygroscopicity of organic-inorganic mixed particles nebulized from water extracts of ambient aerosols collected in Sapporo, Japan during summer 2005. The hygroscopicity of 100 nm particles was measured using a hygroscopicity tandem differential mobility analyzer (HTDMA) at 5-95% relative humidity. The chemical analyses of the extracts showed that inorganic salts accounted for 32-84% of the water-soluble fraction and that the remaining was water-soluble organic matter (WSOM). The liquid water content (LWC) of particles was primarily governed by the relative abundance of inorganic salts in particles. The chemical closure with a thermodynamic model did not indicate a significant perturbation of LWC by WSOM at 85% RH with the consideration of the uncertainties estimated. However, a positive perturbation by WSOM was suggested at 50% RH. Individual oxygenated compounds identified using gas chromatography were not abundant enough to substantially increase the LWC at 85% RH.

  1. Virus-Like Particle Vaccination Protects Nonhuman Primates from Lethal Aerosol Exposure with Marburgvirus (VLP Vaccination Protects Macaques against Aerosol Challenges).

    Science.gov (United States)

    Dye, John M; Warfield, Kelly L; Wells, Jay B; Unfer, Robert C; Shulenin, Sergey; Vu, Hong; Nichols, Donald K; Aman, M Javad; Bavari, Sina

    2016-04-08

    Marburg virus (MARV) was the first filovirus to be identified following an outbreak of viral hemorrhagic fever disease in Marburg, Germany in 1967. Due to several factors inherent to filoviruses, they are considered a potential bioweapon that could be disseminated via an aerosol route. Previous studies demonstrated that MARV virus-like particles (VLPs) containing the glycoprotein (GP), matrix protein VP40 and nucleoprotein (NP) generated using a baculovirus/insect cell expression system could protect macaques from subcutaneous (SQ) challenge with multiple species of marburgviruses. In the current study, the protective efficacy of the MARV VLPs in conjunction with two different adjuvants: QS-21, a saponin derivative, and poly I:C against homologous aerosol challenge was assessed in cynomolgus macaques. Antibody responses against the GP antigen were equivalent in all groups receiving MARV VLPs irrespective of the adjuvant; adjuvant only-vaccinated macaques did not demonstrate appreciable antibody responses. All macaques were subsequently challenged with lethal doses of MARV via aerosol or SQ as a positive control. All MARV VLP-vaccinated macaques survived either aerosol or SQ challenge while animals administered adjuvant only exhibited clinical signs and lesions consistent with MARV disease and were euthanized after meeting the predetermined criteria. Therefore, MARV VLPs induce IgG antibodies recognizing MARV GP and VP40 and protect cynomolgus macaques from an otherwise lethal aerosol exposure with MARV.

  2. Virus-Like Particle Vaccination Protects Nonhuman Primates from Lethal Aerosol Exposure with Marburgvirus (VLP Vaccination Protects Macaques against Aerosol Challenges

    Directory of Open Access Journals (Sweden)

    John M. Dye

    2016-04-01

    Full Text Available Marburg virus (MARV was the first filovirus to be identified following an outbreak of viral hemorrhagic fever disease in Marburg, Germany in 1967. Due to several factors inherent to filoviruses, they are considered a potential bioweapon that could be disseminated via an aerosol route. Previous studies demonstrated that MARV virus-like particles (VLPs containing the glycoprotein (GP, matrix protein VP40 and nucleoprotein (NP generated using a baculovirus/insect cell expression system could protect macaques from subcutaneous (SQ challenge with multiple species of marburgviruses. In the current study, the protective efficacy of the MARV VLPs in conjunction with two different adjuvants: QS-21, a saponin derivative, and poly I:C against homologous aerosol challenge was assessed in cynomolgus macaques. Antibody responses against the GP antigen were equivalent in all groups receiving MARV VLPs irrespective of the adjuvant; adjuvant only-vaccinated macaques did not demonstrate appreciable antibody responses. All macaques were subsequently challenged with lethal doses of MARV via aerosol or SQ as a positive control. All MARV VLP-vaccinated macaques survived either aerosol or SQ challenge while animals administered adjuvant only exhibited clinical signs and lesions consistent with MARV disease and were euthanized after meeting the predetermined criteria. Therefore, MARV VLPs induce IgG antibodies recognizing MARV GP and VP40 and protect cynomolgus macaques from an otherwise lethal aerosol exposure with MARV.

  3. Aerosol deposition and origin in French mountains estimated with soil inventories of 210Pb and artificial radionuclides

    Science.gov (United States)

    Le Roux, Gaël; Pourcelot, Laurent; Masson, Olivier; Duffa, Céline; Vray, Françoise; Renaud, Philippe

    Radionuclide inventories were measured in soils from different French mountainous areas: Chaîne des Puys (Massif Central), Eastern Corsica, Jura, Montagne Noire, Savoie, Vosges and Rhine Valley. 210Pb soil inventories were used to estimate long-term (>75 yr) deposition of submicron aerosols. Whereas 210Pb total deposition is explained partly by wet deposition, as demonstrated by increase of 210Pb inventory with annual rainfall; a part of 210Pb in the soils of higher altitude is caused by orographic depositions. Using measurements of radionuclides coming from nuclear aerial weapon tests ( 137Cs and Pu isotopes), we were able to estimate the origin of aerosols deposited in high-altitude sites and to confirm the importance of occult deposition and feeder-seeder mechanism. Using a simple mass balance model, we estimate that occult deposition and feeder-seeder mechanisms account to more than 50% of total deposition of 210Pb and associated submicron aerosols in French altitude sites.

  4. The chemical composition of fine ambient aerosol particles in the Beijing area

    Science.gov (United States)

    Nekat, Bettina; van Pinxteren, Dominik; Iinuma, Yoshiteru; Gnauk, Thomas; Müller, Konrad; Herrmann, Hartmut

    2010-05-01

    The strong economical growth in China during the last few decades led to heavy air pollution caused by significantly increased particle emissions. The aerosol particles affect not only the regional air quality and visibility, but can also influence cloud formation processes and the radiative balance of the atmosphere by their optical and microphysical properties. The ability to act as Cloud Condensation Nuclei (CCN) is related to microphysical properties like the hygroscopic growth or the cloud droplet activation. The chemical composition of CCN plays an important role on these properties and varies strongly with the particle size and the time of day. Hygroscopic or surface active substances can increase the hygroscopicity and lower the surface tension of the particle liquid phase, respectively. The presence of such compounds may result in faster cloud droplet activation by faster water uptake. The DFG project HaChi (Haze in China) aimed at studying physical and chemical parameters of urban aerosol particles in the Beijing area in order to associate the chemical composition of aerosol particles with their ability to act as CCN. To this end, two measurement campaigns were performed at the Wuqing National Ordinary Meteorological Observing Station, which is a background site near Beijing. The winter campaign was realized in March 2009 and the summer campaign took place from mid July 2009 to mid August 2009. Fine particles with an aerodynamic diameter smaller than or equal 1 μm were continuously sampled for 24h over the two campaigns using a DIGITEL high volume sampler (DHA-80). The present contribution presents and discusses the results of the chemical characterization of the DIGITEL filters samples. The filters were analyzed for the mass concentration, inorganic ions and carbon sum parameters like elemental (EC), organic (OC) and water soluble organic carbon (WSOC). The WSOC fraction was further characterized for hygroscopic substances like low molecular

  5. Impacts of aerosol particles on the microphysical and radiative properties of stratocumulus clouds over the Southeast Pacific ocean

    Directory of Open Access Journals (Sweden)

    C. H. Twohy

    2012-08-01

    Full Text Available The Southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles such as power plants, urban pollution and smelters on the stratocumulus deck was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, droplets were collected and evaporated using a counterflow virtual impactor (CVI, and the non-volatile residual particles were analyzed.

    Many flights focused on the gradient in cloud properties on an E-W track along 20° S from near the Chilean coast to remote areas offshore. Mean statistics from seven flights and many individual legs were compiled. Consistent with a continental source of cloud condensation nuclei, below-cloud accumulation-mode aerosol and droplet number concentration generally decreased from near shore to offshore. Single particle analysis was used to reveal types and sources of the enhanced particle number. While a variety of particle types were found throughout the region, the dominant particles near shore were partially neutralized sulfates. Modeling and chemical analysis indicated that the predominant source of these particles in the marine boundary layer along 20° S was anthropogenic pollution from central Chilean sources, with copper smelters a relatively small contribution.

    Cloud droplets were more numerous and smaller near shore, and there was less drizzle. Higher droplet number concentration and physically thinner clouds both contributed to the smaller droplets near shore. Satellite measurements were used to show that cloud albedo was highest 500–1000 km offshore, and actually lower closer to shore due to the generally thinner clouds and lower liquid water paths

  6. Magnetic particles extracted from manganese nodules: Suggested origin from stony and iron meteorites

    Science.gov (United States)

    Finkelman, R.B.

    1970-01-01

    On the basis of x-ray diffraction and electron microprobe data, spherical and ellipsoidal particles extracted from manganese nodules were divided into three groups. Group I particles are believed to be derived from iron meteorites, and Group II particles from stony meteorites. Group III particles are believed to be volcanic in origin.

  7. Measurements of Ultra-fine and Fine Aerosol Particles over Siberia: Large-scale Airborne Campaigns

    Science.gov (United States)

    Arshinov, Mikhail; Paris, Jean-Daniel; Stohl, Andreas; Belan, Boris; Ciais, Philippe; Nédélec, Philippe

    2010-05-01

    In this paper we discuss the results of in-situ measurements of ultra-fine and fine aerosol particles carried out in the troposphere from 500 to 7000 m in the framework of several International and Russian State Projects. Number concentrations of ultra-fine and fine aerosol particles measured during intensive airborne campaigns are presented. Measurements carried over a great part of Siberia were focused on particles with diameters from 3 to 21 nm to study new particle formation in the free/upper troposphere over middle and high latitudes of Asia, which is the most unexplored region of the Northern Hemisphere. Joint International airborne surveys were performed along the following routes: Novosibirsk-Salekhard-Khatanga-Chokurdakh-Pevek-Yakutsk-Mirny-Novosibirsk (YAK-AEROSIB/PLARCAT2008 Project) and Novosibirsk-Mirny-Yakutsk-Lensk-Bratsk-Novosibirsk (YAK-AEROSIB Project). The flights over Lake Baikal was conducted under Russian State contract. Concentrations of ultra-fine and fine particles were measured with automated diffusion battery (ADB, designed by ICKC SB RAS, Novosibirsk, Russia) modified for airborne applications. The airborne ADB coupled with CPC has an additional aspiration unit to compensate ambient pressure and changing flow rate. It enabled to classify nanoparticles in three size ranges: 3-6 nm, 6-21 nm, and 21-200 nm. To identify new particle formation events we used similar specific criteria as Young et al. (2007): (1) N3-6nm >10 cm-3, (2) R1=N3-6/N621 >1 and R2=N321/N21200 >0.5. So when one of the ratios R1 or R2 tends to decrease to the above limits the new particle formation is weakened. It is very important to notice that space scale where new particle formation was observed is rather large. All the events revealed in the FT occurred under clean air conditions (low CO mixing ratios). Measurements carried out in the atmospheric boundary layer over Baikal Lake did not reveal any event of new particle formation. Concentrations of ultra

  8. Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki ─ Part II: Aerosol measurements within the SAPPHIRE project

    Directory of Open Access Journals (Sweden)

    A. Karppinen

    2007-08-01

    Full Text Available This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August–19 September 2003 and 14 January–11 February 2004. The available information also included electronic traffic counts, on-site meteorological measurements, and urban background particle number size distribution measurement. The ultrafine particle (UFP, diameter<100 nm number concentrations at the roadside site were approximately an order of magnitude higher than those at the urban background site during daytime and downwind conditions. Both the modal structure analysis of the particle number size distributions and the statistical correlation between the traffic density and the UFP number concentrations indicate that the UFP were evidently from traffic related emissions. The modeling exercise included the evolution of the particle number size distribution nearby the road during downwind conditions. The model simulation results revealed that the evaluation of the emission factors of aerosol particles might not be valid for the same site during different time.

  9. Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation

    Directory of Open Access Journals (Sweden)

    S.-L. Sihto

    2008-06-01

    Full Text Available We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation mechanism with a linear dependence on the sulphuric acid concentration or ternary H2O-H2SO4-NH3 nucleation was assumed. We investigated the factors that affect the sulphuric acid dependence during the early stages of particle growth, and tried to find conditions which would yield the linear dependence between the particle number concentration at 3–6 nm and sulphuric acid, as observed in field experiments. The simulations showed that the correlation with sulphuric acid may change during the growth from nucleation size to 3–6 nm size range, the main reason being the size dependent growth rate between 1 and 3 nm. In addition, the assumed size for the nucleated clusters had a crucial impact on the sulphuric acid dependence at 3 nm. The simulations yielded a linear dependence between the particle number concentration at 3 nm and sulphuric acid, when a low saturation vapour pressure for the condensable organic vapour was assumed, or when nucleation took place at ~2 nm instead of ~1 nm. Comparison of results with activation and ternary nucleation showed that ternary nucleation cannot explain the experimentally observed linear or square dependence on sulphuric acid.

  10. Experimental determination of the regional deposition of aerosol particles in the human respiratory tract

    Energy Technology Data Exchange (ETDEWEB)

    Stahlhofen, W.; Gebhart, J.; Heyder, J.

    1980-06-01

    The experimental techniques and the results of inhalation studies with radioaerosols on normal non-smokers for mouth-breathing are described and discussed. Monodisperse iron oxide particles tagged with /sup 198/Au are produced with a spinning top generator in the aerodynamic size range between 1 to 10 ..mu..m. An aerosol inhalation apparatus enables the subjects to breathe under standardized conditions with respect to tidal volume and breathing frequency. The calculation of total deposition is based upon measurements of the number of in- and exhaled particles per breath by means of photometric methods and pneumotachography. The retention of the radioactive particles present in the body after aerosol administration is measured with a body counter designed and constructed for these experiments. Retention measurements as functions of time after inhalation are carried out in extrathoracic-, chest- and stomach-position. The body counter consists of four shielded NaF(Tl)-dectors. Characteristic feature of the body counter is its low sensitivity to neighboring organs and to neighboring regions within the respiratory tract. For the evaluation of extrathoracic deposition, the activity measured in the stomach immediately after inhalation is added to extrathoracic activity. The elimination of material from the chest is found to be much slower for the material deposited in the alveolar region than for the amount deposited in the tracheobronchial tree. This allows the intrathoracic deposition to be divided into tracheolbronchial and alveolar deposition by means of the different slopes of the normalized chest retention function. Different normalized chest retention functions are presented and analyzed with respect to their different elimination rats belonging to the tracheobronchial and alveolar region. Total, tracheobronchial, alveolar and extrathoracic deposition data are reported in the aerodynamic diameter range between 1 and 10 ..mu..m.

  11. Regional-scale simulations of fungal spore aerosols using an emission parameterization adapted to local measurements of fluorescent biological aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Hummel

    2014-04-01

    Full Text Available Fungal spores as a prominent type of primary biological aerosol particles (PBAP have been incorporated into the COSMO-ART regional atmospheric model, using and comparing three different emission parameterizations. Two literature-based emission rates derived from fungal spore colony counts and chemical tracer measurements were used as a parameterization baseline for this study. A third, new emission parameterization was adapted to field measurements of fluorescent biological aerosol particles (FBAP from four locations across Northern Europe. FBAP concentrations can be regarded as a lower estimate of total PBAP concentrations. Size distributions of FBAP often show a distinct mode at approx. 3 μm, corresponding to a diameter range characteristic for many fungal spores. Previous studies have suggested the majority of FBAP in several locations are dominated by fungal spores. Thus, we suggest that simulated fungal spore concentrations obtained from the emission parameterizations can be compared to the sum of total FBAP concentrations. A comparison reveals that parameterized estimates of fungal spore concentrations based on literature numbers underestimate measured FBAP concentrations. In agreement with measurement data, the model results show a diurnal cycle in simulated fungal spore concentrations, which may develop partially as a consequence of a varying boundary layer height between day and night. Measured FBAP and simulated fungal spore concentrations also correlate similarly with simulated temperature and humidity. These meteorological variables, together with leaf area index, were chosen to drive the new emission parameterization discussed here. Using the new emission parameterization on a model domain covering Western Europe, fungal spores in the lowest model layer comprise a fraction of 15% of the total aerosol mass over land and reach average number concentrations of 26 L−1. The results confirm that fungal spores and biological particles

  12. Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Patrik T., E-mail: patrik.nilsson@design.lth.se; Isaxon, Christina [Lund University, Ergonomics and Aerosol Technology (Sweden); Eriksson, Axel C. [Lund University, Nuclear Physics (Sweden); Messing, Maria E. [Lund University, Solid State Physics (Sweden); Ludvigsson, Linus; Rissler, Jenny [Lund University, Ergonomics and Aerosol Technology (Sweden); Hedmer, Maria; Tinnerberg, Håkan [Lund University, Division of Occupational and Environmental Medicine, Department of Laboratory Medicine (Sweden); Gudmundsson, Anders [Lund University, Ergonomics and Aerosol Technology (Sweden); Deppert, Knut [Lund University, Solid State Physics (Sweden); Bohgard, Mats; Pagels, Joakim H. [Lund University, Ergonomics and Aerosol Technology (Sweden)

    2013-11-15

    Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time- and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02–10 μm, were dominated by large agglomerates (1–5 μm). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (10{sup 3}–10{sup 5}/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments.

  13. ROLE OF AEROSOL PARTICLE IN THE TRANSMISSION OF INFLUENZA A VIRUS

    Directory of Open Access Journals (Sweden)

    Putu Yuniadi Antari

    2013-05-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Transmission of the Influenza A virus has been widely studied by scientists, as influenza states itself a disease capable of easily causing worldwide pandemic. Influenza pandemics are mediated by its virus, which holds the ability to undergo mutation in a vast speed. As a threatening nosocomial infection especially among patients with a high risk of contamination, influenza must be given serious attention. The objective of this article is to comprehend the effectiveness of aerosol particles in influenza transmission, as well as the role of health care centers in facilitating the spreading of this disease. Reviews in this article show that experimental animals demonstrate how aerosol particles do play a role in the transmission of the disease. In its relation with health care facilities, reviews show that different hospitals or clinics represent various numbers of aerosol particles necessary for causing clinical symptoms and signs of influenza in a group of patients. On the other hand, basic precaution instruments significantly reduce influenza transmission. In addition, this study also reviews a number of possible actions to prevent further transmission. Commitment and teamwork of involved stakeholders are necessary to ensure public awareness and initiate health promotions to eliminate any possibility of further pandemics. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso

  14. Organic peroxides' gas-particle partitioning and rapid heterogeneous decomposition on secondary organic aerosol

    Science.gov (United States)

    Li, Huan; Chen, Zhongming; Huang, Liubin; Huang, Dao

    2016-02-01

    Organic peroxides, important species in the atmosphere, promote secondary organic aerosol (SOA) aging, affect HOx radicals cycling, and cause adverse health effects. However, the formation, gas-particle partitioning, and evolution of organic peroxides are complicated and still unclear. In this study, we investigated in the laboratory the production and gas-particle partitioning of peroxides from the ozonolysis of α-pinene, which is one of the major biogenic volatile organic compounds in the atmosphere and an important precursor for SOA at a global scale. We have determined the molar yields of hydrogen peroxide (H2O2), hydromethyl hydroperoxide (HMHP), peroxyformic acid (PFA), peroxyacetic acid (PAA), and total peroxides (TPOs, including unknown peroxides) and the fraction of peroxides in α-pinene/O3 SOA. Comparing the gas-phase peroxides with the particle-phase peroxides, we find that gas-particle partitioning coefficients of PFA and PAA are 104 times higher than the values from the theoretical prediction, indicating that organic peroxides play a more important role in SOA formation than previously expected. Here, the partitioning coefficients of TPO were determined to be as high as (2-3) × 10-4 m3 µg-1. Even so, more than 80 % of the peroxides formed in the reaction remain in the gas phase. Water changes the distribution of gaseous peroxides, while it does not affect the total amount of peroxides in either the gas or the particle phase. Approx. 18 % of gaseous peroxides undergo rapid heterogeneous decomposition on SOA particles in the presence of water vapor, resulting in the additional production of H2O2. This process can partially explain the unexpectedly high H2O2 yields under wet conditions. Transformation of organic peroxides to H2O2 also preserves OH in the atmosphere, helping to improve the understanding of OH cycling.

  15. a Search for the Cosmic Dust Increment to Aerosol Particles at the Geographic South Pole.

    Science.gov (United States)

    Witkowski, Robert Edward

    1988-12-01

    An electrostatic precipitation (ESP) particle collector was constructed and deployed to sample the South Pole, Antarctica atmosphere for submicron-size cosmic dust particles. It was in operation between December, 1983 and January, 1987 at the National Oceanic and Atmospheric Administration (NOAA) Clean Air Facility (CAF). The collector is most efficient for particles in the 0.3 mu m size range. An arrangement of isolation shutters and removable sampling plates allows for sample transfer, without contamination, to a remote laboratory for individual particle characterization by Scanning Transmission Electron Microscopy (STEM) coupled with Energy Dispersive Spectrometry (EDS) for elemental analysis and Selected Area Electron Diffraction (SAED) for crystallographic identifications. Beside the readily identifiable contaminants, including sulfuric acid droplets that make up a significant background and sooty carbonaceous-type material, a variety of rod-shaped grains and spheres have been noted. In addition, an iron-containing mineral has been observed as fragile filamentary or needle-like crystalline aggregates. Some rather rare particles that display single element EDS signature peaks of Ti, Cr, Co, Mg, Si, and Pb and a possible Cr, Fe intermetallic or mineral particle also have been observed. While it would not be surprising for cosmic dust grains to be small in size and to have simple compositions, any concrete evidence of an extraterrestrial origin for any of these grains is lacking. Two other types of particles show a stronger possibility of cosmic origin. These are an Al, Fe particle collected during a Perseids Meteor Event and a unique particle that contains Mg, Al, Si, S, Ca, Fe and Ni in chondritic proportions. After completion of the particle collection program, the collector was shut down and returned to the laboratory for evaluation. An area of one of the stainless steel plates from the first chamber of the collector, the particle -charging section, was

  16. Differences in aerosol absorption Ångström exponents between correction algorithms for a particle soot absorption photometer measured on the South African Highveld

    Science.gov (United States)

    Backman, J.; Virkkula, A.; Vakkari, V.; Beukes, J. P.; Van Zyl, P. G.; Josipovic, M.; Piketh, S.; Tiitta, P.; Chiloane, K.; Petäjä, T.; Kulmala, M.; Laakso, L.

    2014-12-01

    Absorption Ångström exponents (AAEs) calculated from filter-based absorption measurements are often used to give information on the origin of the ambient aerosol, for example, to distinguish between urban pollution and biomass burning aerosol. Filter-based absorption measurements are widely used and are common at aerosol monitoring stations globally. Several correction algorithms are used to account for artefacts associated with filter-based absorption techniques. These algorithms are of profound importance when determining the absolute amount of absorption by the aerosol. However, this study shows that there are substantial differences between the AAEs calculated from these corrections. Depending on the used correction, AAEs can change by as much as 46%. The study also highlights that the difference between AAEs calculated using different corrections can lead to conflicting conclusions on the type of aerosol when using the same data set. The AAE ranged between 1.17 for non-corrected data to 1.96 for the correction that gave the greatest values. Furthermore, the study implies that the AAEs reported for a site depend on at which filter transmittance the filter is changed. In this work, the AAEs were calculated from data measured with a three-wavelength particle soot absorption photometer (PSAP) at Elandsfontein on the South African Highveld for 23 months. The sample air of the PSAP was diluted to prolong filter change intervals, by a factor of 15. The correlation coefficient between the dilution-corrected PSAP and a non-diluted Multi-Angle Absorption Photometer (MAAP) was 0.9. Thus, the study also shows that the applicability of the PSAP can be extended to remote sites that are not often visited or suffer from high levels of pollution.

  17. The relative importance of competing pathways for the formation of high-molecular-weight peroxides in the ozonolysis of organic aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Mochida

    2006-01-01

    Full Text Available High-molecular-weight (HMW organic compounds are an important component of atmospheric particles, although their origins, possibly including in situ formation pathways, remain incompletely understood. This study investigates the formation of HMW organic peroxides through reactions involving stabilized Criegee intermediates (SCI's. The model system is methyl oleate (MO mixed with dioctyl adipate (DOA and myristic acid (MA in submicron aerosol particles, and Criegee intermediates are formed by the ozonolysis of the double bond in methyl oleate. An aerosol flow tube coupled to a quadrupole aerosol mass spectrometer (AMS is employed to determine the relative importance of different HMW organic peroxides following the ozonolysis of different mixing mole fractions of MO in DOA and MA. Possible peroxide products include secondary ozonides (SOZ's, α-acyloxyalkyl hydroperoxides and α-acyloxyalkyl alkyl peroxides (αAAHP-type compounds, diperoxides, and monoperoxide oligomers. Of these, the AMS data identify two SOZ's as major HMW products in the ozonolysis of pure methyl oleate as well as in an inert matrix of DOA to as low as 0.04 mole fraction MO. In comparison, in mixed particles of MO and MA, αAAHP-type compounds form in high yields for MO mole fractions of 0.5 or less, suggesting that SCI's efficiently attack the carboxylic acid group of myristic acid. The reactions of SCI's with carboxylic acid groups to form αAAHP-type compounds therefore compete with those of SCI's with aldehydes to form SOZ's, provided that both types of functionalities are present at significant concentrations. The results therefore suggest that SCI's in atmospheric particles contribute to the transformation of carboxylic acids and other protic groups into HMW organic peroxides.

  18. Fluorescent biological aerosol particle concentrations and size distributions measured with an ultraviolet aerodynamic particle sizer (UV-APS) in Central Europe

    OpenAIRE

    J. A. Huffman; Treutlein, B.; U. Pöschl

    2009-01-01

    Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure ...

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

    Directory of Open Access Journals (Sweden)

    I. Salma

    2011-02-01

    Full Text Available Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 103 to 29 ×103 cm−3 with a yearly median of 11.8 × 103 cm−3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H2SO4 concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO2, which was present in a yearly median concentration of 6.7 μg m−3. This suggests that the precursor gas was always available in excess

  20. Aerosol particle properties in the tropical free troposphere observed at Pico Espejo (4765 m a.s.l., Venezuela

    Directory of Open Access Journals (Sweden)

    T. Schmeißner

    2010-11-01

    Full Text Available The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere were performed from March 2007 until Mai 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS system and a Condensational Particle Counter (CPC. The analysis of the annual and diurnal variability of the tropical free troposphere (FT aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (519±613 cm−3, lowest during the wet season (318±194 cm−3. The more humid FT contained generally higher aerosol particle number concentrations (573±768 cm−3 during dry season, 320±195 cm−3 during wet season than the dry FT (454±332 cm−3 during dry season, 275±172 cm−3 during wet season, indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

  1. Performance evaluation of selected n95 respirators and surgical masks when challenged with aerosolized endospores and inert particles.

    Science.gov (United States)

    Davidson, Craig S; Green, Christopher F; Gibbs, Shawn G; Schmid, Kendra K; Panlilio, Adelisa L; Jensen, Paul A; Scarpino, Pasquale V

    2013-01-01

    The objective of this study was to assess how the relative efficiency of N95 respirators and surgical masks might vary with different challenge aerosols, utilizing a standardized manikin head form as a surrogate to human participation. A Collision nebulizer aerosolized B. anthracis Sterne strain endospores and polystyrene latex (PSL) particles to evaluate 11 models of N95 respirators and surgical masks. An automated breathing simulator, calibrated to normal tidal volume and active breathing rate, mimicked human respiration. A manikin head form with N95 respirators or surgical masks, and manikin head form without N95 respirators or surgical masks were placed in the bioaerosol chamber. An AGI-30 sampler filled with phosphate buffered water was fitted behind the mouth of each manikin head form to collect endospore bioaerosol samples. PSL aerosols concentrations were quantified by an ARTI Hand Held Particle Counter. Geometric Mean (GM) relative efficiency of N95 respirators and surgical masks challenged with endospore bioaerosol ranged from 34-65%. In PSL aerosol experiments, GM relative efficiency ranged from 35-64% for 1.3 μm particles. GM filtration efficiency of all N95 and surgical N95 respirators filter media evaluated was ≥99% when challenged with particles ≥0.1 μm. GM filtration efficiency of surgical mask filter media ranged from 70-83% with particles ≥0.1 μm and 74-92% with 1.3 μm PSL particles. Relative efficiencies of N95 respirators and surgical masks challenged with aerosolized B. anthracis endospores and PSL were similar. Relative efficiency was similar between N95 respirators and surgical masks on a manikin head form despite clear differences in filtration efficiency. This study further highlights the importance of face seal leakage in the respiratory protection provided by N95 respirators, and demonstrates it on a human surrogate.

  2. On the composition of ammonia-sulfuric-acid ion clusters during aerosol particle formation

    Science.gov (United States)

    Schobesberger, S.; Franchin, A.; Bianchi, F.; Rondo, L.; Duplissy, J.; Kürten, A.; Ortega, I. K.; Metzger, A.; Schnitzhofer, R.; Almeida, J.; Amorim, A.; Dommen, J.; Dunne, E. M.; Ehn, M.; Gagné, S.; Ickes, L.; Junninen, H.; Hansel, A.; Kerminen, V.-M.; Kirkby, J.; Kupc, A.; Laaksonen, A.; Lehtipalo, K.; Mathot, S.; Onnela, A.; Petäjä, T.; Riccobono, F.; Santos, F. D.; Sipilä, M.; Tomé, A.; Tsagkogeorgas, G.; Viisanen, Y.; Wagner, P. E.; Wimmer, D.; Curtius, J.; Donahue, N. M.; Baltensperger, U.; Kulmala, M.; Worsnop, D. R.

    2015-01-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new-particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small NH3-H2SO4 clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm/Δn = 1.05 and were only observed at sufficiently high [NH3] / [H2SO4]. The H2SO4 molecules of these clusters are partially neutralized by NH3, in close resemblance to the acid-base bindings of ammonium bisulfate. Supported by model simulations, we substantiate previous evidence for acid-base reactions being the essential mechanism behind the formation of these clusters under atmospheric conditions and up to sizes of at least 2 nm. Our results also suggest that electrically neutral NH3-H2SO4 clusters, unobservable in this study, have generally the same composition as ionic clusters for [NH3] / [H2SO4] > 10. We expect that NH3-H2SO4 clusters form and grow also mostly by Δm/Δn > 1 in the atmosphere's boundary layer, as [NH3] / [H2SO4] is mostly larger than 10. We compared our results from CLOUD with APi-TOF measurements of NH3-H2SO4 anion clusters during new-particle formation in the Finnish boreal forest. However, the exact role of NH3-H2SO4 clusters in boundary layer particle formation remains to be resolved.

  3. On the composition of ammonia-sulfuric acid clusters during aerosol particle formation

    Science.gov (United States)

    Schobesberger, S.; Franchin, A.; Bianchi, F.; Rondo, L.; Duplissy, J.; Kürten, A.; Ortega, I. K.; Metzger, A.; Schnitzhofer, R.; Almeida, J.; Amorim, A.; Dommen, J.; Dunne, E. M.; Ehn, M.; Gagné, S.; Ickes, L.; Junninen, H.; Hansel, A.; Kerminen, V.-M.; Kirkby, J.; Kupc, A.; Laaksonen, A.; Lehtipalo, K.; Mathot, S.; Onnela, A.; Petäjä, T.; Riccobono, F.; Santos, F. D.; Sipilä, M.; Tomé, A.; Tsagkogeorgas, G.; Viisanen, Y.; Wagner, P. E.; Wimmer, D.; Curtius, J.; Donahue, N. M.; Baltensperger, U.; Kulmala, M.; Worsnop, D. R.

    2014-05-01

    The formation of particles from precursor vapors is an important source of atmospheric aerosol. Research at the Cosmics Leaving OUtdoor Droplets (CLOUD) facility at CERN tries to elucidate which vapors are responsible for this new particle formation, and how in detail it proceeds. Initial measurement campaigns at the CLOUD stainless-steel aerosol chamber focused on investigating particle formation from ammonia (NH3) and sulfuric acid (H2SO4). Experiments were conducted in the presence of water, ozone and sulfur dioxide. Contaminant trace gases were suppressed at the technological limit. For this study, we mapped out the compositions of small NH3-H2SO4 clusters over a wide range of atmospherically relevant environmental conditions. We covered [NH3] in the range from 10. Positively charged clusters grew on average by Δm / Δn = 1.05 and were only observed at sufficiently high [NH3] / [H2SO4]. The H2SO4 molecules of these clusters are partially neutralized by NH3, in close resemblance to the acid-base bindings of ammonium bisulfate. Supported by model simulations, we substantiate previous evidence for acid-base reactions being the essential mechanism behind the formation of these clusters under atmospheric conditions and up to sizes of at least 2 nm. Our results also suggest that yet unobservable electrically neutral NH3-H2SO4 clusters grow by generally the same mechanism as ionic clusters, particularly for [NH3] / [H2SO4]>10. We expect that NH3-H2SO4 clusters form and grow also mostly by Δm / Δn>1 in the atmosphere's boundary layer, as [NH3] / [H2SO4] is mostly larger than 10. We compared our results from CLOUD with APi-TOF measurements of NH3-H2SO4 anion clusters during new particle formation in the Finnish boreal forest. However, the exact role of NH3-H2SO4 clusters in boundary layer particle formation remains to be resolved.

  4. Possible effect of extreme solar energetic particle event of 20 January 2005 on polar stratospheric aerosols: direct observational evidence

    Directory of Open Access Journals (Sweden)

    I. A. Mironova

    2011-05-01

    Full Text Available Energetic cosmic rays are the main source of ionization of the low-middle atmosphere, leading to associated changes in atmospheric properties. Via the hypothetical influence of ionization on aerosol growth and facilitated formation of cloud condensation nuclei, this may be an important indirect link relating solar variability to climate. This effect is highly debated, however, since the proposed theoretical mechanisms still remain illusive and qualitative, and observational evidence is inconclusive and controversial. Therefore, important questions regarding the existence and magnitude of the effect, and particularly the fraction of aerosol particles that can be formed and grow large enough to influence cloud condensation nuclei (CCN, are still open. Here we present empirical evidence of the possible effect caused by cosmic rays upon polar stratospheric aerosols, based on a case study of an extreme solar energetic particle (SEP event of 20 January 2005. Using aerosol data obtained over polar regions from different satellites with optical instruments that were operating during January 2005, such as the Stratospheric Aerosol and Gas Experiment III (SAGE III, and Optical Spectrograph and Infrared Imaging System (OSIRIS, we found a significant simultaneous change in aerosol properties in both the southern and northern polar regions in temporal association with the SEP event. We speculate that ionization of the atmosphere, which was abnormally high during this extreme SEP event, might have led to formation of new particles and/or growth of preexisting ultrafine particles up to the size of CCN. However, a detailed interpretation of the effect is left for subsequent studies. This is the first time high vertical resolution measurements have been used to provide evidence for the probable production of stratospheric CCN from cosmic ray induced ionization.

  5. Possible effect of extreme solar energetic particle events of September–October 1989 on polar stratospheric aerosols: a case study

    Directory of Open Access Journals (Sweden)

    I. A. Mironova

    2013-02-01

    Full Text Available The main ionization source of the middle and low Earth atmosphere is related to energetic particles coming from outer space. Usually it is ionization from cosmic rays that is always present in the atmosphere. But in a case of a very strong solar eruption some solar energetic particles (SEP can reach middle/low atmosphere increasing the ionization rate up to some orders of magnitude at polar latitudes. We continue investigating such a special class of solar events and their possible applications for natural variations of the aerosol content. After the case study of the extreme SEP event of January 2005 and its possible effect upon polar stratospheric aerosols, here we analyze atmospheric applications of the second sequence of several events that took place over the Autumn 1989. Using aerosol data obtained over polar regions from two satellites with space-borne optical instruments SAGE II and SAM II that were operating during September–October 1989, we found that an extreme major SEP event might have led to formation of new particles and/or growth of preexisting ultrafine particles in the polar stratospheric region. However, the effect of the additional ambient air ionization on the aerosol formation is minor, in comparison with temperature effect, and can take place only in the cold polar atmospheric conditions.

  6. Evidence for surface nucleation: efflorescence of ammonium sulfate and coated ammonium sulfate aerosol particles

    Science.gov (United States)

    Ciobanu, V. Gabriela; Marcolli, Claudia; Krieger, Ulrich K.; Zuend, Andreas; Peter, Thomas

    2010-05-01

    Aerosol particles are ubiquitous in the atmosphere and can undergo different phase transitions, such as deliquescence and efflorescence. Using optical microscopy, we investigated the efflorescence of ammonium sulfate (AS) in supersaturated AS and 1:1 and 8:1 (by weight) poly(ethylene glycol)-400 (PEG-400)/AS particles, which were deposited as droplets with diameters in the 16 - 35 μm range on a hydrophobically coated slide. The PEG-400/AS particles that are exposed to decreasing relative humidity (RH) exhibit a liquid-liquid phase separation below 90 % RH with the PEG-400 phase surrounding the aqueous AS inner phase (Marcolli and Krieger, 2006; Ciobanu et al., 2009). Pure AS particles effloresced in the RH range from 36.3 to 43.7 % RH, in agreement with literature data (31 - 48 % RH). In contrast, 1:1 PEG-400/AS particles with diameters of the AS phase from 7.2 - 19.2 μm effloresced between 26.8 - 33.9 % RH and 8:1 PEG-400/AS particles with diameters of the AS phase from 1.8 - 7.3 μm between 24.3 - 29.3 % RH. Such low efflorescence relative humidity (ERH) values have never been reached before for AS particles of this size range. We show that neither a potential inhibition of water evaporation via anomalously slow diffusion through the PEG coating, nor the presence of low amounts of PEG-400 in the AS phase, nor different timescales between various experimental techniques could possibly explain the low AS ERH values of PEG-400/AS particles in our setup. High-speed photography of the efflorescence process allowed to monitor the proceeding of the AS crystallization fronts within the particles with millisecond time resolution. The nucleation locations were deduced based on the initial crystals growth locations. Statistical analysis of 31 and 19 efflorescence events for pure AS and 1:1 PEG-400/AS particles, respectively, identified the air/droplet/substrate contact line and the air/droplet interface as preferred nucleation locations in the case of pure AS particles

  7. Pilot Study of Inhaled Aerosols Targeted via Magnetic Alignment of High Aspect Ratio Particles in Rabbits

    Directory of Open Access Journals (Sweden)

    Gillian E. S. Redman

    2011-01-01

    Full Text Available Recently, inhaled pharmaceutical aerosols have seen increased investigation in the treatment of lung cancer, where the inability to deliver adequate therapeutic drug concentrations to tumour sites may be overcome with improved targeted delivery to the site of the tumour. In this study, the feasibility of magnetically targeted delivery of high aspect ratio particles loaded with iron oxide nanoparticles was studied in 19 New Zealand White rabbits. Half of the exposed rabbits had a magnetic field placed externally over their right lung. Iron sensitive magnetic resonance images of the lungs were acquired to determine the iron concentrations in the right and left lung of each animal. The right/left ratio increased in the middle and basal regions of the lung where, due to the morphology of the rabbit lung, this method of targeting is most effective. With further optimization, this technique could be an effective method for increasing the dose of drug delivered to a specific site within the lung.

  8. The rural carbonaceous aerosols in coarse, fine, and ultrafine particles during haze pollution in northwestern China.

    Science.gov (United States)

    Zhu, Chong-Shu; Cao, Jun-Ji; Tsai, Chuen-Jinn; Shen, Zhen-Xing; Liu, Sui-Xin; Huang, Ru-Jin; Zhang, Ning-ning; Wang, Ping

    2016-03-01

    The carbonaceous aerosol concentrations in coarse particle (PM10: Dp ≤ 10 μm, particulate matter with an aerodynamic diameter less than 10 μm), fine particle (PM2.5: Dp ≤ 2.5 μm), and ultrafine particle (PM0.133: Dp ≤ 0.133 μm) carbon fractions in a rural area were investigated during haze events in northwestern China. The results indicated that PM2.5 contributed a large fraction in PM10. OC (organic carbon) accounted for 33, 41, and 62 % of PM10, PM2.5, and PM0.133, and those were 2, 2.4, and 0.4 % for EC (elemental carbon) in a rural area, respectively. OC3 was more abundant than other organic carbon fractions in three PMs, and char dominated EC in PM10 and PM2.5 while soot dominated EC in PM0.133. The present study inferred that K(+), OP, and OC3 are good biomass burning tracers for rural PM10 and PM2.5, but not for PM0.133 during haze pollution. Our results suggest that biomass burning is likely to be an important contributor to rural PMs in northwestern China. It is necessary to establish biomass burning control policies for the mitigation of severe haze pollution in a rural area.

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

    Science.gov (United States)

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

    2009-04-01

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

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

    Directory of Open Access Journals (Sweden)

    D. G. Georgakopoulos

    2008-04-01

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

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

    Directory of Open Access Journals (Sweden)

    D. G. Georgakopoulos

    2009-04-01

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

  12. 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.

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

    CERN Document Server

    Curci, Gabriele

    2014-01-01

    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 analyze aerosol optical depth $\\tau_{\\rm a}(z)$ values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of the Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.04$ - and shows a seasonal trend with a winter minimum - $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.03$ -, and a summer maximum - $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.06$ -, and an unexpected increase from August to September - $\\tau_{\\rm a}(3.5~{\\rm km})\\sim 0.055$). 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 t...

  14. The 2005 Study of Organic Aerosols at Riverside (SOAR-1: instrumental intercomparisons and fine particle composition

    Directory of Open Access Journals (Sweden)

    K. S. Docherty

    2011-02-01

    Full Text Available Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR to investigate sources and chemical composition of fine particles (PMf in the inland region of Southern California. This paper briefly summarizes the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July–15 August and provides detailed intercomparisons of complementary measurements and average PMf composition during this period. Daily meteorology and gas-phase species concentrations were highly repetitive with meteorological and gas-phase species concentrations displaying clear diurnal cycles and weekday/weekend contrast, with organic aerosol (OA being the single largest component contributing approximately one-third of PMf mass. In contrast with historical characterizations of OA in the region, several independent source apportionment efforts attributed the vast majority (~80% of OA mass during SOAR-1 to secondary organic aerosol (SOA. Given the collocation of complementary aerosol measurements combined with a dominance of SOA during SOAR-1, this paper presents new results on intercomparisons among several complementary measurements and on PMf composition during this period. Total non-refractory submicron (NR-PM1 measurements from a high-resolution aerosol mass spectrometer (HR-AMS are compared with measurements by tapered element oscillating microbalances (TEOM including a filter dynamics measurement system (TEOMFDMS. NR-PM1 is highly correlated with PM2.5 TEOMFDMS measurements and accounts for the bulk of PM2.5 mass with the remainder contributed primarily by refractory material. In contrast, measurements from a heated TEOM show substantial losses of semi-volatile material, including ammonium nitrate and semi-volatile organic material. Speciated HR-AMS measurements are

  15. Observations of meteoric material and implications for aerosol nucleation in the winter Arctic lower stratosphere derived from in situ particle measurements

    Directory of Open Access Journals (Sweden)

    J. Curtius

    2005-01-01

    Full Text Available Number concentrations of total and non-volatile aerosol particles with size diameters >0.01 μm as well as particle size distributions (0.4–23 μm diameter were measured in situ in the Arctic lower stratosphere (10–20.5 km altitude. The measurements were obtained during the campaigns European Polar Stratospheric Cloud and Lee Wave Experiment (EUPLEX and Envisat-Arctic-Validation (EAV. The campaigns were based in Kiruna, Sweden, and took place from January to March 2003. Measurements were conducted onboard the Russian high-altitude research aircraft Geophysica using the low-pressure Condensation Nucleus Counter COPAS (COndensation PArticle Counter System and a modified FSSP 300 (Forward Scattering Spectrometer Probe. Around 18–20 km altitude typical total particle number concentrations nt range at 10–20 cm−3 (ambient conditions. Correlations with the trace gases nitrous oxide (N2O and trichlorofluoromethane (CFC-11 are discussed. Inside the polar vortex the total number of particles >0.01 μm increases with potential temperature while N2O is decreasing which indicates a source of particles in the above polar stratosphere or mesosphere. A separate channel of the COPAS instrument measures the fraction of aerosol particles non-volatile at 250°C. Inside the polar vortex a much higher fraction of particles contained non-volatile residues than outside the vortex (~67% inside vortex, ~24% outside vortex. This is most likely due to a strongly increased fraction of meteoric material in the particles which is transported downward from the mesosphere inside the polar vortex. The high fraction of non-volatile residual particles gives therefore experimental evidence for downward transport of mesospheric air inside the polar vortex. It is also shown that the fraction of non-volatile residual particles serves directly as a suitable experimental vortex tracer. Nanometer-sized meteoric smoke particles may also serve as nuclei for the condensation of

  16. Numerical advection of correlated tracers: preserving particle size/composition moment sequences during transport of aerosol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    McGraw, Robert [Atmospheric Sciences Division, Environmental Sciences Department Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2007-07-15

    Nonlinear transport algorithms designed to reduce numerical diffusion fail to preserve correlations between moments, isotope abundances, etc. when these scalar densities are transported in models as separate tracers. In case of the particle size/composition coordinates of an aerosol, such loss can give rise to unphysical moment sets. New statistical approaches to aerosol dynamics, which involve tracking moments directly, offer highly efficient alternatives to sectional and modal methods for representing aerosols in climate models, but it is essential that moment set integrity be preserved throughout a simulation. In this paper we review the problem and weaknesses of previous attempts at solution, including vector transport - a scheme in which the moments, as internal aerosol coordinates, are transported together with a single lead tracer such as number or mass. A non-negative least squares (NNLS) solution that finally eliminates the problem without requiring modification of the transport algorithm itself is presented. Following each transport step, new moment sets are resolved into sums of previously validated sets with non-negative coefficients using NNLS Transport errors are removed and the now guaranteed-to-be-valid moment sets are ready for passage to the aerosol dynamics module. In addition to moment set validation, the new scheme reduces numerical diffusion during transport and provides greater accuracy for the source apportionment of aerosol mixtures. The method is not limited to moment transport - similar improvements in accuracy are expected using NNLS in conjunction with modal and sectional methods.

  17. Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe

    Science.gov (United States)

    Huffman, J. A.; Treutlein, B.; Pöschl, U.

    2010-04-01

    Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure Fluorescent Biological Aerosol Particles (FBAPs), which provide an estimate of viable bioaerosol particles and can be regarded as an approximate lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (particles (1-20 μm). Averaged over the four-month measurement period (August-December 2006), the mean number concentration of coarse FBAPs was ~3×10-2 cm-3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1μg m-3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10-2 cm-3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle (24-h) with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical analyses of PBAPs in aerosol

  18. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2004-01-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2 (g SO4-2-1, which compare to US values of 0.030 and 13.9 m2 (g SO4-2-1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m-2 are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL=-0.750, FU=-0.930, and DFU,L=24% for full sky calculations without clouds and FL=-0.485, FU=-0.605, and DFU,L=25% when clouds are included. Regionally, DFU,L=48% over the USA, 55% over Europe

  19. Synergetic formation of secondary inorganic and organic aerosol: effect of SO2 and NH3 on particle formation and growth

    Science.gov (United States)

    Chu, Biwu; Zhang, Xiao; Liu, Yongchun; He, Hong; Sun, Yele; Jiang, Jingkun; Li, Junhua; Hao, Jiming

    2016-11-01

    The effects of SO2 and NH3 on secondary organic aerosol formation have rarely been investigated together, while the interactive effects between inorganic and organic species under highly complex pollution conditions remain uncertain. Here we studied the effects of SO2 and NH3 on secondary aerosol formation in the photooxidation system of toluene/NOx in the presence or absence of Al2O3 seed aerosols in a 2 m3 smog chamber. The presence of SO2 increased new particle formation and particle growth significantly, regardless of whether NH3 was present. Sulfate, organic aerosol, nitrate, and ammonium were all found to increase linearly with increasing SO2 concentrations. The increases in these four species were more obvious under NH3-rich conditions, and the generation of nitrate, ammonium, and organic aerosol increased more significantly than sulfate with respect to SO2 concentration, while sulfate was the most sensitive species under NH3-poor conditions. The synergistic effects between SO2 and NH3 in the heterogeneous process contributed greatly to secondary aerosol formation. Specifically, the generation of NH4NO3 was found to be highly dependent on the surface area concentration of suspended particles, and increased most significantly with SO2 concentration among the four species under NH3-rich conditions. Meanwhile, the absorbed NH3 might provide a liquid surface layer for the absorption and subsequent reaction of SO2 and organic products and, therefore, enhance sulfate and secondary organic aerosol (SOA) formation. This effect mainly occurred in the heterogeneous process and resulted in a significantly higher growth rate of seed aerosols compared to without NH3. By applying positive matrix factorisation (PMF) analysis to the AMS data, two factors were identified for the generated SOA. One factor, assigned to less-oxidised organic aerosol and some oligomers, increased with increasing SO2 under NH3-poor conditions, mainly due to the well-known acid catalytic effect of

  20. Interaction of aerosol particles composed of protein and saltswith water vapor: hygroscopic growth and microstructural rearrangement

    Directory of Open Access Journals (Sweden)

    E. Mikhailov

    2004-01-01

    Full Text Available The interaction of aerosol particles composed of the protein bovine serum albumin (BSA and the inorganic salts sodium chloride and ammonium nitrate with water vapor has been investigated by hygroscopicity tandem differential mobility analyzer (H-