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Sample records for airborne mineral dust

  1. Mineralogical, Chemical, and Optical Interrelationships of Airborne Mineral Dusts

    NASA Astrophysics Data System (ADS)

    Engelbrecht, J. P.; Moosmuller, H.; Pincock, S. L.; Jayanty, R. K. M.; Casuccio, G.

    2014-12-01

    The purpose of the project was to provide information on the mineralogical, chemical and physical interrelationships of re-suspended mineral dust samples collected as grab samples from global dust sources. Surface soil samples were collected from about 65 desert sites, including the southwestern USA (12), Mali (3), Chad (3), Morocco (1), Canary Islands (8), Cape Verde (1), Djibouti (1), Afghanistan (3), Iraq (6), Kuwait (5), Qatar (1), UAE (1), Serbia (3), China (5), Namibia (3), Botswana (4), Australia (3), and Chile (1). The < 38 μm sieved fraction of each sample was re-suspended in an entrainment chamber, from which the airborne mineral dust could be monitored, sampled and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5 particulate mass fractions, an aerodynamic particle size (APS) analyzer, and a three wavelength (405, 532, 781nm) photoacoustic resonator with integrating reciprocal nephelometer for monitoring absorption and scattering coefficients during the dust re-suspension process. Filter sample media included Teflon® membrane and quartz fiber filters for chemical analysis (71 species), and Nuclepore® filters for individual particle analysis by Scanning Electron Microscopy (SEM). The < 38 μm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the > 38 μm, < 125 μm soil fractions were mineralogically characterized by optical microscopy. We will be presenting results on the optical measurements, also showing the relationship between single scattering albedo (SSA) at three different wavelengths, and chemical as well as mineralogical content and interdependencies of the entrained dust samples. Examples showing the relationships between the single scattering albedos of airborne dusts, and iron (Fe) in hematite, goethite, and clay minerals (montmorillonite, illite, palygorskite), will

  2. On the visibility of airborne volcanic ash and mineral dust

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Sauer, D. N.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B. C.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-12-01

    After the eruption of the Eyjafjalla volcano (Iceland) in April 2010 which caused the most extensive restrictions of the airspace over Europe since the end of World War II, the aviation safety concept of avoiding "visible ash", i.e. volcanic ash that can be seen by the human eye, was recommended. However so far, no clear definition of "visible ash" and no relation between the visibility of an aerosol layer and related aerosol mass concentrations are available. The goal of our study is to assess whether it is possible from the pilot's perspective in flight to detect the presence of volcanic ash and to distinguish between volcanic ash and other aerosol layers just by sight. In our presentation, we focus the comparison with other aerosols on aerosol types impacting aviation: Besides volcanic ash, dust storms are known to be avoided by aircraft. We use in-situ and lidar data as well photographs taken onboard the DLR research aircraft Falcon during the Saharan Mineral Dust Experiments (SAMUM) in 2006 and 2008 and during the Eyjafjalla volcanic eruption in April/May 2010. We complement this analysis with numerical modelling, using idealized radiative transfer simulations with the 3D Monte Carlo radiative transfer code MYSTIC for a variety of selected viewing geometries. Both aerosol types, Saharan mineral dust and volcanic ash, show an enhanced coarse mode (> 1 μm) aerosol concentration, but volcanic ash aerosol additionally contains a significant number of Aitken mode particles (< 150 nm). Volcanic ash is slightly more absorbing than mineral dust, and the spectral behaviour of the refractive index is slightly different. According to our simulations, these differences are not detectable just by human eye. Furthermore, our data show, that it is difficult to define a lower threshold for the visibility of an aerosol layer because the visual detectability depends on many parameters, including the thickness of the aerosol layer, the brightness and color contrast between the

  3. The role of airborne mineral dusts in human disease

    NASA Astrophysics Data System (ADS)

    Morman, Suzette A.; Plumlee, Geoffrey S.

    2013-06-01

    Exposure to fine particulate matter (PM) is generally acknowledged to increase risk for human morbidity and mortality. However, particulate matter (PM) research has generally examined anthropogenic (industry and combustion by-products) sources with few studies considering contributions from geogenic PM (produced from the Earth by natural processes, e.g., volcanic ash, windborne ash from wildfires, and mineral dusts) or geoanthropogenic PM (produced from natural sources by processes that are modified or enhanced by human activities, e.g., dusts from lakebeds dried by human removal of water, dusts produced from areas that have undergone desertification as a result of human practices). Globally, public health concerns are mounting, related to potential increases in dust emission from climate related changes such as desertification and the associated long range as well as local health effects. Recent epidemiological studies have identified associations between far-traveled dusts from primary sources and increased morbidity and mortality in Europe and Asia. This paper provides an outline of public health research and history as it relates to naturally occurring inorganic mineral dusts. We summarize results of current public health research and describe some of the many challenges related to understanding health effects from exposures to dust aerosols.

  4. Assessing sources of airborne mineral dust and other aerosols, in Iraq

    NASA Astrophysics Data System (ADS)

    Engelbrecht, Johann P.; Jayanty, R. K. M.

    2013-06-01

    Most airborne particulate matter in Iraq comes from mineral dust sources. This paper describes the statistics and modeling of chemical results, specifically those from Teflon® filter samples collected at Tikrit, Balad, Taji, Baghdad, Tallil and Al Asad, in Iraq, in 2006/2007. Methodologies applied to the analytical results include calculation of correlation coefficients, Principal Components Analysis (PCA), and Positive Matrix Factorization (PMF) modeling. PCA provided a measure of the covariance within the data set, thereby identifying likely point sources and events. These include airborne mineral dusts of silicate and carbonate minerals, gypsum and salts, as well as anthropogenic sources of metallic fumes, possibly from battery smelting operations, and emissions of leaded gasoline vehicles. Five individual PMF factors (source categories) were modeled, four of which being assigned to components of geological dust, and the fifth to gasoline vehicle emissions together with battery smelting operations. The four modeled geological components, dust-siliceous, dust-calcic, dust-gypsum, and evaporate occur in variable ratios for each site and size fraction (TSP, PM10, and PM2.5), and also vary by season. In general, Tikrit and Taji have the largest and Al Asad the smallest percentages of siliceous dust. In contrast, Al Asad has the largest proportion of gypsum, in part representing the gypsiferous soils in that region. Baghdad has the highest proportions of evaporite in both size fractions, ascribed to the highly salinized agricultural soils, following millennia of irrigation along the Tigris River valley. Although dust storms along the Tigris and Euphrates River valleys originate from distal sources, the mineralogy bears signatures of local soils and air pollutants.

  5. Transport of mineral dust derived from airborne wind lidar measurements during SALTRACE

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Groß, Silke; Rahm, Stephan; Freudenthaler, Volker; Toledano, Carlos; Weinzierl, Bernadett

    2015-04-01

    During the SALTRACE field experiment conducted between the 10 of June and the 15 of July 2013, the transport and properties of Saharan dust were characterized by a 2-µm Doppler wind lidar (DWL) deployed on the DLR Falcon 20 research aircraft. Unlike aerosol lidars, the DLW is able to simultaneously measure wind fields and -by means of an adequate calibration- aerosol optical properties, which is more adequate for aerosol transport studies. The retrieved horizontal and vertical wind speed provide a direct observation of dust long range transport mechanisms across the Atlantic (e.g. by the African easterly jet) from Western Africa to the Caribbean. Vertical wind observations revealed the structure of island induced lee waves in the Cape Verde and Barbados regions. A novel method for the calibration of DWLs based on simultaneous measurements with a ground-based aerosol lidar and sun photometer was developed. After being calibrated, the system is able to retrieve quantitative aerosol backscatter and extinction coefficients, which is usually not obtained from coherent lidars. Results from the validation with a ground-based aerosol lidar in Barbados and the CALIPSO satellite instrument will be discussed.

  6. Aging of mineral dust during transport from the Sahara into the Cape Verde area - results from airborne measurements during SAMUM

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Sauer, D.; Esselborn, M.; Petzold, A.; Veira, A.; Rose, M.; Mund, S.; Wirth, M.; Ansmann, A.; Tesche, M.; Groß, S.; Freudenthaler, V.

    2012-04-01

    The Saharan Mineral Dust Experiment (SAMUM) was conducted to better understand the properties of fresh and aged mineral dust. Within SAMUM, two field missions were performed: SAMUM-1 (summer 2006, Morocco) focused on the chemical, microphysical, optical and radiative properties of fresh dust aerosol in the vertical column over the Sahara, while SAMUM-2 (winter 2008, Cape Verde) concentrated on the properties of aged dust and the mixing of mineral dust with biomass burning aerosol. During both field experiments, the DLR Falcon research aircraft was equipped with an extensive set of aerosol instruments for size, volatility, and absorption measurements, impactor sampling for chemical analyses and with a nadir-looking High Spectral Resolution Lidar (HSRL). In the Cape Verde area, we found a complex stratification with dust covering the altitude range below 2 km and tropical biomass burning layers aloft. We show that the aerosol type of individual aerosol layers can be classified based on depolarization and lidar ratios and, in addition, on in situ measured Ångström exponents of absorption åap. The dust layers had a geometrical depth of 1.3 ± 0.4 km and showed a median åap of 3.95. The median effective diameter Deff was 2.5 μm and the dust layers over Cape Verde yielded clear signals of aging: large particles were depleted due to gravitational settling and the accumulation mode diameter was shifted towards larger sizes as a result of coagulation. The tropical biomass layers had a depth of 2.0 ± 1.1 km and were characterized by a median åap of 1.34. They always contained a certain amount of large dust particles and showed a median Deff of 1.1 μm and a fine mode Deff,fine of 0.33. The dust and biomass burning layers had a median aerosol optical depth (AOD) of 0.23 and 0.09, respectively. The median contributions of the dust and biomass burning layers to the AOD of the total atmospheric column below 10 km were 75 and 37%, respectively. We present the properties of

  7. Coal miners' mortality in relaton to radiological category, lung function and exposure to airborne dust. Final report

    SciTech Connect

    Miller, B.G.; Jacobsen, M.; Steele, R.C.

    1981-06-01

    This report describes mortality among 29,553 British coal miners. They represent 93.5% of 31,611 men who were surveyed radiologically at 24 coal mines in the period 1953 through 1958. The main aim of the work was to consider risks of death attributed to various underlying causes, as recorded on death certificates, in relation to radiological signs of pneumoconiosis, measures of lung function, and exposure to respirable coal mine dust.

  8. Remote Sensing of Mineral Dust Sources (Invited)

    NASA Astrophysics Data System (ADS)

    Sprigg, W. A.; Morain, S. A.

    2009-12-01

    Thirty-four percent of Earth's land surface is arid, home to two billion people routinely exposed to airborne dust and increased risk of cardiovascular and respiratory disease. The NASA-supported Public Health Applications in Remote Sensing project has improved the process of simulating and predicting when and where dust storms will occur and the consequent particulate air quality. Partnerships with state public health offices test model products for epidemiological and health surveillance applications. The key to significant improvement in simulations, forecasts and their use has been identifying and monitoring mineral dust sources via satellite based sensors.

  9. Exposure to mineral sands dust particles

    NASA Astrophysics Data System (ADS)

    Dias da Cunha, K.; Barros Leite, C. V.; Zays, Z.

    2004-06-01

    The aim of this study is to characterize the airborne particles in a Brazilian region with high concentration of mineral sands (Buena village). In this study proton induced X-ray emission (PIXE), plasma desorption mass spectrometry and alpha spectrometry were used for analyses of airborne particles. The analyses of aerosol samples and lichen samples show that the inhabitants of the Buena village are exposed to airborne particles in the fine fraction of aerosols. The main anthropogenic sources of particles are the mineral sands processing plant and truck traffic, and natural sources as the sea, soil and the swamp. The results from the lichen samples show that at least during the last 15 years the inhabitants of the village have been exposed to monazite particles. The results from aerosols and lichens samples also suggested that the swamp is a source of 226Ra and 210Pb bearing particles besides the monazite dust.

  10. Pneumoconiosis, lung function and exposure to airborne dust: epidemiological research to compare responses of working coalminers with responses of ex-miners. Part 2. Final report

    SciTech Connect

    Soutar, C.A.; Maclaren, W.; Hurley, F.; Murdoch, R.; Hadden, G.

    1982-03-01

    The relationship between dust exposure and disease for miners was compared with that for ex-miners, in order to determine whether relationships found in other studies on miners alone could be applied to both groups. 17,738 men examined in the 1950s were followed up approximately 22 years later. Sixty one per cent of the survivors were examined, being 40% of the original sample. Records were made of respiratory symptoms, smoking habit, lung spirometry and chest radiograph findings. Radiographs were interpreted according to the International Labour Office Classification of Pneumoconiosis. Lifetime dust exposure was calculated for each subject. The dust/disease relationship was found to be the same for both groups. Ex-miners were found to have more pneumoconiosis and fibrosis and to be in worse health than miners. Pneumoconiosis progression was shown to be related to continued dust exposure; fibrosis progression was related to the presence of dust in the lungs. Dust exposure was shown to cause a mainly restrictive pattern of lung disease in contrast to the obstructive pattern caused by smoking. Colliery-related differences were found in lung disease which it was felt needed further investigation.

  11. Airborne Dust in Space Vehicles and Habitats

    NASA Technical Reports Server (NTRS)

    James, John

    2006-01-01

    Airborne dust, suspended inside a space vehicle or in future celestial habitats, can present a serious threat to crew health if it is not controlled. During the Apollo missions to the moon, lunar dust brought inside the capsule caused eye irritation and breathing difficulty to the crew when they launched from the moon and re-acquired "microgravity." During Shuttle flights reactive and toxic dusts such as lithium hydroxide have created a risk to crew health, and fine particles from combustion events can be especially worrisome. Under nominal spaceflight conditions, airborne dusts and particles tend to be larger than on earth because of the absence of gravity settling. Aboard the ISS, dusts are effectively managed by HEPA filters, although floating dust in newly-arrived modules can be a nuisance. Future missions to the moon and to Mars will present additional challenges because of the possibility that external dust will enter the breathing atmosphere of the habitat and reach the crew's respiratory system. Testing with simulated lunar and Martian dust has shown that these materials are toxic when placed into the lungs of test animals. Defining and evaluating the physical and chemical properties of Martian dusts through robotic missions will challenge our ability to prepare better dust simulants and to determine the risk to crew health from exposure to such dusts.

  12. Airborne Dust Models in Valley Fever Research

    NASA Astrophysics Data System (ADS)

    Sprigg, W. A.; Galgiani, J. N.; Vujadinovic, M.; Pejanovic, G.; Vukovic, A. J.; Prasad, A. K.; Djurdjevic, V.; Nickovic, S.

    2011-12-01

    Dust storms (haboobs) struck Phoenix, Arizona, in 2011 on July 5th and again on July 18th. One potential consequence: an estimated 3,600 new cases of Valley Fever in Maricopa County from the first storm alone. The fungi, Coccidioides immitis, the cause of the respiratory infection, Valley Fever, lives in the dry desert soils of the American southwest and southward through Mexico, Central America and South America. The fungi become part of the dust storm and, a few weeks after inhalation, symptoms of Valley Fever may appear, including pneumonia-like illness, rashes, and severe fatigue. Some fatalities occur. Our airborne dust forecast system predicted the timing and extent of the storm, as it has done with other, often different, dust events. Atmosphere/land surface models can be part of public health services to reduce risk of Valley Fever and exacerbation of other respiratory and cardiovascular illness.

  13. Interactions Between Mineral Dust, Climate, and Ocean Ecosystems

    NASA Technical Reports Server (NTRS)

    Gasso, Santiago; Grassian, Vicki H.; Miller, Ron L.

    2010-01-01

    Over the past decade, technological improvements in the chemical and physical characterization of dust have provided insights into a number of phenomena that were previously unknown or poorly understood. In addition, models are now incorporating a wider range of physical processes, which will allow us to better quantify the climatic and ecological impacts of dust. For example, some models include the effect of dust on oceanic photosynthesis and thus on atmospheric CO 2 (Friedlingstein et al. 2006). The impact of long-range dust transport, with its multiple forcings and feedbacks, is a relatively new and complex area of research, where input from several disciplines is needed. So far, many of these effects have only been parameterized in models in very simple terms. For example, the representation of dust sources remains a major uncertainty in dust modeling and estimates of the global mass of airborne dust. This is a problem where Earth scientists could make an important contribution, by working with climate scientists to determine the type of environments in which easily erodible soil particles might have accumulated over time. Geologists could also help to identify the predominant mineralogical composition of dust sources, which is crucial for calculating the radiative and chemical effects of dust but is currently known for only a few regions. Understanding how climate and geological processes control source extent and characterizing the mineral content of airborne dust are two of the fascinating challenges in future dust research.

  14. Airborne dust particle counting techniques.

    PubMed

    Sharma, S G; Prasad, B D

    2006-03-01

    The paper briefly describes an electro-optical system for counting of dust particles, which is based on the scattering phenomena. Utilizing the scattering of light by various size particles present in the environment, various particle counting techniques have been developed in order to measure the scattered intensity of light. Light scatters in all directions but much more in the so-called near forward direction 17( composite function) off axis, at 163( composite function) from the light source in the visible range. On the basis of two techniques, the right angle and forward angle scattering, opto-mechanical systems have been developed which measure scattered intensity and particulate matter. The forward scattering Nephelometer is more sensitive and therefore is more suitable for pollution monitoring than the right angle scattering Nephelometer. Whereas the right angle scattering Nephelometer has the utility in extremely low concentration in ppb level owing to the excellent light trap efficiency in comparison to forward scattering Nephelometer. In this paper measurement techniques and measurement results associated with design and development of a real time particle analyser are also discussed.

  15. Statistical analysis of the size and elemental composition of airborne coal mine dust

    SciTech Connect

    Lee, C.

    1986-01-01

    The specific purpose of this thesis is to analyze two of the basic characteristics of airborne coal mine dust, size and elemental composition, and to study their ramifications on dust control measures and medical studies of coal workers' pneumoconiosis. A dust-sampling strategy using multi-stage cascade impactors is established for characterization purposes. Analysis of the size data based upon the aerodynamic diameter is performed to examine the two assumptions implicitly made in the current practice for coal mine dust size presentation; lognormality and unimodality in the mass size distribution. The bimodal lognormal model is able to identify the major modal patterns observed in the empirical models. Association of the elemental composition of coal with the rank is tested to be significant. Size dependency and locational variation of elemental composition of airborne coal mine dust are significant. The size dependency is more significant in the immediate return of the continuous miner operation and the elements showing significant locational variability are found to be enriched near the roof bolter operation. The coal seam is the main source of major elements in airborne coal mine dust, while no consistent relationship exists for the trace elements. The significance of the dust in the intake air as a potential source for the elements in airborne coal mine dust is shown. Dust reentrained along the shuttle car route is also found to be a significant dust source. Dust particles in the respirable size range are likely to transport through the working area.

  16. Lunar Airborne Dust Toxicity Hazard Assessments (Invited)

    NASA Astrophysics Data System (ADS)

    Cooper, B. L.; McKay, D. S.; Taylor, L. A.; Wallace, W. T.; James, J.; Riofrio, L.; Gonzalez, C. P.

    2009-12-01

    The Lunar Airborne Dust Toxicity Assessment Group (LADTAG) is developing data to set the permissible limits for human exposure to lunar dust. This standard will guide the design of airlocks and ports for EVA, as well as the requirements for filtering and monitoring the atmosphere in habitable vehicles, rovers and other modules. LADTAG’s recommendation for permissible exposure limits will be delivered to the Constellation Program in late 2010. The current worst-case exposure limit of 0.05 mg/m3, estimated by LADTAG in 2006, reflects the concern that lunar dust may be as toxic as quartz dust. Freshly-ground quartz is known to be more toxic than un-ground quartz dust. Our research has shown that the surfaces of lunar soil grains can be more readily activated by grinding than quartz. Activation was measured by the amount of free radicals generated—activated simulants generate Reactive Oxygen Species (ROS) i.e., production of hydroxyl free radicals. Of the various influences in the lunar environment, micrometeorite bombardment probably creates the most long-lasting reactivity on the surfaces of grains, although solar wind impingement and short-wavelength UV radiation also contribute. The comminution process creates fractured surfaces with unsatisfied bonds. When these grains are inhaled and carried into the lungs, they will react with lung surfactant and cells, potentially causing tissue damage and disease. Tests on lunar simulants have shown that dissolution and leaching of metals can occur when the grains are exposed to water—the primary component of lung fluid. However, simulants may behave differently than actual lunar soils. Rodent toxicity testing will be done using the respirable fraction of actual lunar soils (particles with physical size of less than 2.5 micrometers). We are currently separating the fine material from the coarser material that comprises >95% of the mass of each soil sample. Dry sieving is not practical in this size range, so a new system

  17. Immune Alterations in Rats Exposed to Airborne Lunar Dust

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Quiriarte, Heather; Nelman, Mayra; Lam, Chiu-wing; James, John T.; Sams, Clarence

    2014-01-01

    The lunar surface is covered by a layer of fine, reactive dust. Very little is known regarding the toxicity of lunar dust on human physiology. This study assessed the toxicity of airborne lunar dust exposure in rats on pulmonary and systemic immune parameters.

  18. Arabian Red Sea coastal soils as potential mineral dust sources

    NASA Astrophysics Data System (ADS)

    Jish Prakash, P.; Stenchikov, Georgiy; Tao, Weichun; Yapici, Tahir; Warsama, Bashir; Engelbrecht, Johann P.

    2016-09-01

    Both Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) satellite observations suggest that the narrow heterogeneous Red Sea coastal region is a frequent source of airborne dust that, because of its proximity, directly affects the Red Sea and coastal urban centers. The potential of soils to be suspended as airborne mineral dust depends largely on soil texture, moisture content and particle size distributions. Airborne dust inevitably carries the mineralogical and chemical signature of a parent soil. The existing soil databases are too coarse to resolve the small but important coastal region. The purpose of this study is to better characterize the mineralogical, chemical and physical properties of soils from the Arabian Red Sea coastal plain, which in turn will help to improve assessment of dust effects on the Red Sea, land environmental systems and urban centers. Thirteen surface soils from the hot-spot areas of windblown mineral dust along the Red Sea coastal plain were sampled for analysis. Analytical methods included optical microscopy, X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), ion chromatography (IC), scanning electron microscopy (SEM) and laser particle size analysis (LPSA). We found that the Red Sea coastal soils contain major components of quartz and feldspar, as well as lesser but variable amounts of amphibole, pyroxene, carbonate, clays and micas, with traces of gypsum, halite, chlorite, epidote and oxides. The range of minerals in the soil samples was ascribed to the variety of igneous and metamorphic provenance rocks of the Arabian Shield forming the escarpment to the east of the Red Sea coastal plain. The analysis revealed that the samples contain compounds of nitrogen, phosphorus and iron that are essential nutrients to marine life. The analytical results from this study will provide a valuable input into dust emission models used in climate

  19. Understanding mineral dusts from the Middle East

    NASA Astrophysics Data System (ADS)

    Engelbrecht, J. P.; McDonald, E.; Gillies, J. A.; Jayanty, J.; Casuccio, G.; Gertler, A.

    2012-12-01

    The purpose of the program was to provide scientifically founded information on the chemical and physical properties of airborne mineral dust collected during a period of approximately one year, largely in 2006, at Djibouti, Afghanistan (Bagram, Khowst), Qatar, United Arab Emirates, Iraq (Balad, Baghdad, Tallil, Tikrit, Taji, Al Asad), and Kuwait (Northern, Central, Coastal, and Southern regions). To fully understand mineral dusts, their chemical and physical properties as well as mineralogical interrelationships were accurately established. Three collocated low volume particulate samplers, one each for the total suspended (TSP), less than 10 μm in aerodynamic diameter (PM10), and less than 2.5 μm in aerodynamic diameter (PM2.5) particulate matter were deployed at each of the 15 sites, operating on a "1 in 6 day" sampling schedule. A total of 3,136 filter samples were collected on a 1-in-6 day schedule, along with one-time bulk soil samples, at each of the 15 sites. Sample media included Teflon® membrane and quartz fiber filters for chemical analysis (71 species), and Nuclepore® filters for individual particle analysis by Scanning Electron Microscopy (SEM). The provisional study of the data revealed three broad air pollution sources: geological dust, smoke from burn pits, and until now unidentified lead-zinc smelters and battery-processing facilities. SEM results and secondary electron imagery show that quartz and other silicate minerals and, to a lesser extent, dolomite and calcite particles are coated by a thin Si-Al-Mg layer, probably the clay minerals palygorskite and/or montmorillonite/illite. Positive Matrix Factorization (PMF) was performed on aerosol samples collected at six military sites in Iraq (Balad, Baghdad, Tallil, Tikrit, Taji, and Al Asad). PMF results reflect chemical differences amongst sources impacting at individual sites, further complicated by the regional geomorphology and meteorology. Sampling sites are seldom impacted by one source at

  20. Short-term variability of mineral dust, metals and carbon emission from road dust resuspension

    NASA Astrophysics Data System (ADS)

    Amato, Fulvio; Schaap, Martijn; Denier van der Gon, Hugo A. C.; Pandolfi, Marco; Alastuey, Andrés; Keuken, Menno; Querol, Xavier

    2013-08-01

    Particulate matter (PM) pollution in cities has severe impact on morbidity and mortality of their population. In these cities, road dust resuspension contributes largely to PM and airborne heavy metals concentrations. However, the short-term variation of emission through resuspension is not well described in the air quality models, hampering a reliable description of air pollution and related health effects. In this study we experimentally show that the emission strength of resuspension varies widely among road dust components/sources. Our results offer the first experimental evidence of different emission rates for mineral dust, heavy metals and carbon fractions due to traffic-induced resuspension. Also, the same component (or source) recovers differently in a road in Barcelona (Spain) and a road in Utrecht (The Netherlands). This finding has important implications on atmospheric pollution modelling, mostly for mineral dust, heavy metals and carbon species. After rain events, recoveries were generally faster in Barcelona rather than in Utrecht. The largest difference was found for the mineral dust (Al, Si, Ca). Tyre wear particles (organic carbon and zinc) recovered faster than other road dust particles in both cities. The source apportionment of road dust mass provides useful information for air quality management.

  1. Deposition Rates and Characterization of Arabian Mineral Dust

    NASA Astrophysics Data System (ADS)

    Puthan Purakkal, J.; Stenchikov, G. L.; Engelbrecht, J. P.

    2015-12-01

    Airborne mineral dust directly and indirectly impacts on global climate, continental and marine biochemistry, human and animal health, agriculture, equipment, and visibility. Annual global dust emissions are poorly known with estimates differing by a factor of at least two. Local dust emission and deposition rates are even less quantified. Dust deposition rate is a key parameter, which helps to constrain the modeled dust budget of the atmosphere. However, dust deposition remains poorly known, due to the limited number of reliable measurements. Simulations and satellite observations suggest that coastal dusts contribute substantially to the total deposition flux into the Red Sea. Starting December 2014, deposition samplers, both the "frisbee" type, and passive samplers for individual particle scanning electron microscopy were deployed at King Abdullah University of Science and Technology (KAUST), along the Red Sea in Saudi Arabia. Sampling periods of one month were adopted. The deposition rates range from 3 g m-2 month-1 for fair weather conditions to 23 g m-2 month-1 for high dust events. The X-ray diffraction (XRD) analyses of deposited dust samples show mineralogical compositions different from any of the parent soils, the former consisting mainly of gypsum, calcite, and smaller amounts of albite, montmorillonite, chlorite, quartz and biotite. The deposited dust samples on the other hand contain more gypsum and less quartz than the previously collected soil samples. This presentation discusses the results from XRD, chemical analysis and SEM-based individual particle analysis of the soils and the deposited dust samples. The monthly dust accumulation rates and their seasonal and spatial variability are compared with the regional model predictions. Data from this study provide an observational basis for validating the regional dust mass balance along the Arabian Red Sea coastal plain.

  2. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust.

    PubMed

    Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine.

  3. Longitudinal study of dust and airborne endotoxin in the home.

    PubMed

    Park, J H; Spiegelman, D L; Burge, H A; Gold, D R; Chew, G L; Milton, D K

    2000-11-01

    To characterize the seasonal variability of endotoxin levels, we measured endotoxin in dust from the bed, bedroom floor, and kitchen floor in 20 homes, and in air from the bedroom in 15 of the homes. All homes were located in the greater Boston, Massachusetts, area and were sampled each month from April 1995 to June 1996. Outdoor air was collected at two locations. We found greater within-home than between-home variance for bedroom floor, kitchen floor, and airborne endotoxin. However, the reverse was true for bed dust endotoxin. Thus, studies using single measurements of dust endotoxin are most likely to reliably distinguish between homes if bed dust is sampled. Dust endotoxin levels were not significantly associated with airborne endotoxin. Airborne endotoxin was significantly (p = 0. 04) and positively associated with absolute humidity in a mixed-effect model adjusting for a random home effect and fixed effect of sampling month and home characteristics. This finding implies that indoor humidity may be an important factor controlling endotoxin exposure. We found a significant (p < 0.05) seasonal effect in kitchen floor dust (spring > fall) and bedroom airborne endotoxin (spring > winter), but not in the other indoor samples. We found significant seasonal pattern in outdoor airborne endotoxin (summer > winter). PMID:11102291

  4. Mineral dust deposition in Western Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Bergmatti, Gilles; Losno, Rémi; Bon Nguyen, Elisabeth; Chevaillier, Servanne; Roulet, Pierre; Sauvage, Stéphane; Coddeville, Patrice; Ouboulmane, Noura; Siour, Guillaume; Tovar Sanchez, Antonio; Massanet, Ana; Morales Baquero, Rafael; Di Sarra, Giogio; Sferlazzo, Damiano; Dulac, François; Fornier, Michel; Coursier, Cyril

    2014-05-01

    North African deserts are the world's largest sources of atmospheric mineral dust produced by aeolian erosion. Saharan dust is frequently transported toward Europe over the Mediterranean basin. When deposited in oceanic areas, mineral dust can constitute a key input of nutrients bioavailable for the oceanic biosphere. For instance, Saharan dust deposited in the in the Mediterranean Sea can be a significant source of nutrient like Fe, P and N during summer and autumn. Our objective is to study the deposition Saharan mineral dust in the western Mediterranean basin and to improve how deposition processes are parameterized in 3D regional models. To quantify the deposition flux of Saharan dust in the western Mediterranean region a specific collector (CARAGA) to sample automatically the insoluble atmospheric particle deposition was developed (LISA-ICARE) and a network of CARAGA collectors have been set up. Since 2011, eight CARAGA are then deployed in Frioul, Casset, Montandon and Ersa in France, Mallorca and Granada in Spain, Lampedusa in Italia, and Medenine in Tunisia, along a South-North gradient of almost 2000km from the North African coast to the South of Europe. We observe 10 well identified dust Saharan deposition events at Lampedusa and 6 at Mallorca for a 1-yr sampling period. These dust events are sporadic and the South-North gradient of deposition intensity and frequency is observed (the highest dust mass sampled at the stations are : 2,66 g.m-2 at Lampedusa ; 0,54 g.m-2 at Majorque ; 0,33 g.m-2 at Frioul ; 0,16 g.m-2 at Casset). The ability of the CHIMERE model to reproduce the deposition measurements is tested. The mineral dust plumes simulated over the western Mediterranean basin are also compared to satellite observations (OMI, MODIS) and in-situ measurements performed during the ChArMEx campaign and in the AERONET stations.

  5. Predicting the Mineral Composition of Dust Aerosols

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Perez, C.; Miller, R. L.; Rodriguez, S.

    2012-12-01

    Models of the soil (''mineral'') dust aerosol cycle, embedded in climate and Earth system models, are essential tools for understanding the causal relationships and feedbacks between dust and climate. Many soil dust schemes in Earth system models use a simplified representation of soil dust aerosols, where the soil dust is distinguished by size bins or size distribution modes, with a globally uniform representation of the mineralogical composition of the particles. Although models with such a simplified assumption about the properties of soil dust particles have already significantly contributed to the understanding of the role of soil dust aerosols in climate, this is a limitation for a number of reasons: 1. The response of clouds and the large-scale circulation depends on the radiative properties like the single scattering albedo, which should vary with the mineral composition of the source region; 2. Chemical processes at the surface of the soil dust particles that form sulfate and nitrate coatings depend on the dust mineral composition; 3. The availability of soil dust minerals as cloud condensation nuclei depends on their hygroscopicity, which in turn depends on the mineral composition; 4. Fertilization of phytoplankton with soluble iron, a process that influences ocean carbon uptake, depends upon mineral types. We present a new version of the soil dust scheme in the NASA GISS Earth System ModelE, which takes into account the mineral composition of the soil dust particles. Soil dust aerosols are represented as a mixture of externally and internally mixed minerals, such as Illite, Kaolinite, Smectite, Calcite, Iron(hydr)oxide, Quartz, Feldspar, and Gypsum, as well as aggregates between Iron(hydr)oxide and each of the minerals. We test two approaches to constrain the mineral composition of the soil dust particles against data from measurements published in literature as well as measurements from Izaña (Tenerife). The comparison between modeled and measured data

  6. Immersion freezing on mineral dust particles

    NASA Astrophysics Data System (ADS)

    Zolles, Tobias; Grothe, Hinrich; Pummer, Bernhard

    2013-04-01

    Mineral dust is considered to play a major role in ice cloud nucleation in the troposphere. More than 1.000 Tg of mineral dust are aerosolized from the ground every year, 1-10% of these reach the upper troposphere [1]. At an altitude of about 8 km ice residual particle analysis has shown that about 50% of all ice nuclei (IN) are mineral dust[2]. In principle, natural occurring dusts may either be IN-active themselves or are carriers of organic and/or biological IN. Up to now the ice nucleation, i.e. cloud glaciation, has not been quantized. However, different authors report a high IN-activity for many mineral dust samples, although a systematic comparison between different minerals is still missing. Therefore, we studied selected mineral dust samples which were characterized by X-ray diffraction, FTIR spectroscopy, and scanning electron microscopy before use. Oil immersion measurements were performed on the most common minerals, clay materials and volcanic ash. The median freezing temperatures range from -21°C up to homogenous freezing at 38°C. Even though quite a few dust samples show a reasonable high IN-activity, their median freezing temperatures are low compared to biological samples [3, 4]. Furthermore, heat treatment of the dusts was applied in order to decompose and to denaturize organic and/or biological surfactants. Finally, some dust samples had a high loss of activity and thus were subjects of further experiments. These mineral dust particles were suspended in water and after an incubation time were removed. In some cases the washing water had become IN-active, but lost its activity after enzymatic treatment. The observed high IN-activity can thus be explained by adsorbed biological materials. The results suggest that some mineral dusts are IN-active, and if it is not intrinsic they may even enhance IN-activity of organic and biological IN if these are adsorbed on the dust particle surface. A relatively high IN-activity of the pure mineral dusts was

  7. Methods to assess airborne concentrations of cotton dust.

    PubMed

    Corn, M

    1987-01-01

    Assessment of concentrations of airborne cotton dust in the factory is necessary to determine adherence to applicable Permissible Exposure Limits (PELs) on a day-to-day basis, as well as for investigatory studies of an epidemiological nature. The latter are required on an ongoing basis to determine the adequacy of PELs to prevent disease in the exposed population. A strategy of sampling includes considerations of the numbers of samples to be obtained for statistical validity and the locations of samples. Current practice is to obtain more "personal samples" of exposure wherever possible, but with regard to cotton dust, instrumentation is not available for such sampling. In the U.S., the vertical elutriator is the instrument of choice for determining the concentrations of cotton dust in air. Results are expressed as milligrams of airborne particulate (cotton dust) per cubic meter. PMID:3434562

  8. Endotoxins in baled cottons and airborne dusts in textile mills in the People's Republic of China.

    PubMed Central

    Olenchock, S A; Christiani, D C; Mull, J C; Ye, T T; Lu, P L

    1983-01-01

    Bulk cotton samples and airborne vertical elutriated cotton dusts were obtained from textile mills in Shanghai, People's Republic of China. Analysis of endotoxin contents revealed that baled cottons which were grown in different countries varied in endotoxin contamination. The two textile mills, which operated at similar overall airborne dust levels, differed markedly in the levels of airborne endotoxins. The data suggest that the biological activity or "toxicity" of airborne cotton dusts may not be correlated directly with gravimetric dust levels. PMID:6639029

  9. Characteristics of airborne coal mine dust and its implication to coal workers' pneumoconiosis

    SciTech Connect

    Kim, H.

    1989-01-01

    Size selective airborne dust samples were collected using 4-stage cassette impactors at nine different locations in continuous mining sections in each of five coal seams located in the Appalachian bituminous coal field. These coal seams were the Upper Freeport, Pittsburgh, Kittanning, Coalburg, and Pocahontas. Mineralogical analyses were performed by an x-ray powder diffraction photographic technique. The distributions of total and respirable dust concentrations were fit best by a log-normal distribution. The effects of the coal seam and the sampling location on dust levels were significant. The results of the particle size distribution analyses suggest that coal mine dust has a multi-modal distribution. The effects of the coal seam and the sampling locations were significant. The distributions obtained were often affected by such mine-related variables as ventilation rate, relative humidity, and the section dimensions. Nine minerals commonly found in the coal mine dust samples collected from the coal seams studied were illite, calcite, kaolinite, quartz, dolomite, siderite, gypsum, anhydrite, and pyrite in descending order of magnitude. Relative abundance of all mineral species except siderite and gypsum was coal seam specific and suggests that existence of coal seam variability of mineral content. Although mineral content was affected by sampling locations and the sections within a mine, the magnitude was small when compared with that of cal seams. Mineral content also appears to be affected by particle size, although no particular pattern was observed.

  10. Airborne Dust, "The Good Guy or the Bad Guy": How Much do We Know?

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee

    2010-01-01

    Processes in generating, transporting, and dissipating the airborne dust particles are global phenomena -African dust regularly reaching the Alps; Asian dust seasonally crossing the Pacific into North America, and ultimately the Atlantic into Europe. One of the vital biogeochemical roles dust storms play in Earth's ecosystem is routinely mobilizing mineral dust, as a source of iron, from deserts into oceans for fertilizing the growth of phytoplankton -the basis of the oceanic food chain. Similarly, these dust-laden airs also supply crucial nutrients for the soil of tropical rain forests, the so-called womb of life that hosts 50-90% of the species on Earth. With massive amounts of dust lifted from desert regions and injected into the atmosphere, however, these dust storms often affect daily activities in dramatic ways: pushing grit through windows and doors, forcing people to stay indoors, causing breathing problems, reducing visibility and delaying flights, and by and large creating chaos. Thus, both increasing and decreasing concentrations of doses result in harmful biological effects; so do the airborne dust particles to our Living Earth. Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such

  11. Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

    NASA Astrophysics Data System (ADS)

    Ryder, C. L.; McQuaid, J. B.; Flamant, C.; Washington, R.; Brindley, H. E.; Highwood, E. J.; Marsham, J. H.; Parker, D. J.; Todd, M. C.; Banks, J. R.; Brooke, J. K.; Engelstaedter, S.; Estellés, V.; Formenti, P.; Garcia-Carreras, L.; Kocha, C.; Marenco, F.; Rosenberg, P.; Sodemann, H.; Allen, C. J. T.; Bourdon, A.; Bart, M.; Cavazos-Guerra, C.; Chevaillier, S.; Crosier, J.; Darbyshire, E.; Dean, A. R.; Dorsey, J. R.; Kent, J.; O'Sullivan, D.; Schepanski, K.; Szpek, K.; Woolley, A.

    2015-01-01

    The Fennec climate program aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE Falcon 20 is described, with specific focus on instrumentation specially developed and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include: (1) the first airborne measurement of dust particles sized up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in-situ observations of processes in SABL clouds showing dust acting as CCN and IN at -15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold-pool (haboob) issued from deep convection over the Atlas, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and dust surface area measurements suggest coarser particles provide a route for ozone depletion, (9) discrepancies between airborne coarse mode size distributions and AERONET sunphotometer retrievals under

  12. Geochemical and microbiological fingerprinting of airborne dust that fell in Canberra, Australia, in October 2002

    NASA Astrophysics Data System (ADS)

    de Deckker, Patrick; Abed, Raeid M. M.; de Beer, Dirk; Hinrichs, Kai-Uwe; O'Loingsigh, Tadhg; Schefuß, Enno; Stuut, Jan-Berend W.; Tapper, Nigel J.; van der Kaars, Sander

    2008-12-01

    During the night of 22-23 October 2002, a large amount of airborne dust fell with rain over Canberra, located some 200 km from Australia's east coast, and at an average altitude of 650 m. It is estimated that during that night about 6 g m-2 of aeolian dust fell. We have conducted a vast number of analyses to "fingerprint" some of the dust and used the following techniques: grain size analysis; scanning electron microscope imagery; major, trace, and rare earth elemental, plus Sr and Nd isotopic analyses; organic compound analyses with respective compound-specific isotope analyses; pollen extraction to identify the vegetation sources; and molecular cloning of 16S rRNA genes in order to identify dust bacterial composition. DNA analyses show that most obtained 16S rRNA sequences belong mainly to three groups: Proteobacteria (25%), Bacteriodetes (23%), and gram-positive bacteria (23%). In addition, we investigated the meteorological conditions that led to the dust mobilization and transport using model and satellite data. Grain sizes of the mineral dust show a bimodal distribution typical of proximal dust, rather than what is found over oceans, and the bimodal aspect of size distribution confirms wet deposition by rain droplets. The inorganic geochemistry points to a source along/near the Darling River in NW New South Wales, a region that is characteristically semiarid, and both the organic chemistry and palynoflora of the dust confirm the location of this source area. Meteorological reconstructions of the event again clearly identify the area near Bourke-Cobar as being the source of the dust. This study paves the way for determining the export of Australian airborne dust both in the oceans and other continents.

  13. Simulations of Mineral Dust Content With CHIMERE-Dust Model

    NASA Astrophysics Data System (ADS)

    Schmechtig, C.; Marticorena, B.; Menut, L.; Bergametti, G.

    2006-12-01

    Simulations of the mineral dust cycle have been performed whith CHIMERE-Dust model over a domain that includes North Africa, the Mediterranean basin and the North Tropical Atlantic Ocean (10S-60N and 90W-90E) with a 1°x1° resolution using the ECMWF (European Center for Medium-Range Weather Forecasts) meteorological fields for two years, 2000 and 2001. As a validation, we compare the simulated dust concentration fields with photometric data from the AERONET network. From the comparisons between the simulated and measured aerosol optical depth for several stations of the Mediterranean basin, the model appears to reproduce correctly the intensity and occurrences of the dust events. Over Western Africa, the results are not as satisfying since some of the most intense dust events observed on the continent and downwind are not captured by the model. In addition, the simulated events are generally underestimated compared to the measured ones. It appears that these differences in the model performances are connected to the origin of the dust plumes. For example, dust plumes coming from Libya are well simulated while dust plumes originating from the Bodélé depression not as frequent as intense as the observations suggest. Soil properties in these two regions are comparable and typical of very erodible surfaces. We thus focused on the comparison between the ECMWF 10m wind speed fields and 10m wind speed measured at the meteorological stations located in both areas. We noticed that over Libya, the measured and ECMWF 10m wind speed are in very good agreement, while the meteorological model does not reproduce the extrema of the measured wind speed in the Bodélé depression. We found that a crude empirical correction of the 10m wind field in the Bodélé Depression significantly improve the simulations in terms of occurrence and of intensity.

  14. Mineral dust transport toward Hurricane Helene (2006)

    NASA Astrophysics Data System (ADS)

    Schwendike, Juliane; Jones, Sarah C.; Vogel, Bernhard; Vogel, Heike

    2016-05-01

    This study investigates the transport of mineral dust from its source regions in West Africa toward the developing tropical cyclone Helene (2006) and diagnoses the resulting properties of the air influencing the tropical cyclonegenesis. The model system COSMO-ART (Consortium for Small-Scale Modelling-Aerosols and Reactive Trace gases) in which the emission and transport of mineral dust as well as the radiation feedback are taken into account, was used. The emission of mineral dust between 9 and 14 September 2006 occurred in association with the relatively strong monsoon flow and northeasterly trade winds, with gust fronts of convective systems over land, and with the Atlantic inflow. Additionally, increased surface wind speed was linked to orographical effects at the Algerian Mountains, Atlas Mountains, and the Hoggar. The dust, as part of the Saharan air layer, is transported at low levels by the monsoon flow, the Harmattan, the northeasterly trade winds, and the monsoon trough, and is transported upward in the convergence zone between Harmattan and monsoon flow, in the baroclinic zone along the West African coastline, and by convection. At around 700 hPa the dust is transported by the African easterly jet. Dry and dust-free air is found to the north-northwest of the developing tropical depression due to descent in an anticyclone. Based on the model data, it was possible to distinguish between dry (from the anticyclone), dry and dusty (from the Harmattan and northeasterly trade winds), and dusty and moist air (from the monsoon flow and in the tropical depression due to convection).

  15. Migration of contaminated soil and airborne particulates to indoor dust.

    PubMed

    Layton, David W; Beamer, Paloma I

    2009-11-01

    We have developed a modeling and measurement framework for assessing transport of contaminated soils and airborne particulates into a residence, their subsequent distribution indoors via resuspension and deposition processes, and removal by cleaning and building exhalation of suspended particles. The model explicitly accounts for the formation of house dust as a mixture of organic matter (OM) such as shed skin cells and organic fibers, soil tracked-in on footwear, and particulate matter (PM) derived from the infiltration of outdoor air. We derived formulas for use with measurements of inorganic contaminants, crustal tracers, OM, and PM to quantify selected transport parameters. Application of the model to residences in the U.S. Midwest indicates that As in ambient air can account for nearly 60% of the As input to floor dust, with soil track-in representing the remainder. Historic data on Pb contamination in Sacramento, CA, were used to reconstruct sources of Pb in indoor dust, showing that airborne Pb was likely the dominant source in the early 1980s. However, as airborne Pb levels declined due to the phase-out of leaded gasoline, soil resuspension and track-in eventually became the primary sources of Pb in house dust.

  16. Dust aerosol optical properties using ground-based and airborne lidar in the framework of FENNEC

    NASA Astrophysics Data System (ADS)

    Marnas, Fabien; Chazette, Patrick; Flamant, Cyrille; Royer, Philippe; Boytard, Mai-Lan; Genau, Pascal; Doira, Pascal; Bruneau, Didier; Pelon, Jacques; Sanak, Joseph

    2013-04-01

    The FENNEC program aims to improve our knowledge of both the role of the Saharan Heat Low (SHL) on the West African monsoon and the interactions between the African continent and the Mediterranean basin through the Saharan dust transport. The Saharan desert is the major source of mineral dust in the world and may significantly impact the air quality over the Western Europe by increasing the particular matter content. Two lidar systems were operated by the French component of the FENNEC project: an airborne lidar which was flown aboard the French Falcon 20 research aircraft and a ground-based lidar which was located in the southeastern part of Spain, close to Marbella. The presence of dust in the Saharan atmospheric boundary layer has been easily highlighted using the lidars and confirmed by ground-based sunphotometer and observations from both MODIS and SEVIRI spaceborne instruments. The simultaneous use of the sunphotometer-derived Angstrom exponent and the lidar-derived backscatter to extinction ratio is appeared to be a good approach to separate the optical contribution of dust from local aerosols for the coastal site. Over Spain, the dust layer was mainly located above the planetary boundary layer with several kilometers thick. Over the tropical Atlantic Ocean and the Mauritania the airborne lidar shows a high planetary boundary layer (~5 km above the mean sea level) associated to strong aerosol optical thickness (> 0.8 at 532 nm). The airborne lidar data have been inverted using both MODIS and SEVIRI-derived aerosol optical thickness. The differences between dust optical properties close to and remote from the sources will be discussed.

  17. Modeling Optical Properties of Mineral Dust over "The Great Indian Desert"

    NASA Astrophysics Data System (ADS)

    Mishra, S.; Tripathi, S. N.

    2007-12-01

    The Thar desert, sometimes also described as 'The Great Indian Desert', lying in the Northwest part of India with an area of 0.32*106 km2, is known to be the source of natural mineral dust . The mineral dust particles are mostly non-spherical having sharp edges, which show different scattering signature compared to that of equivalent spheres while interacting with the radiation. Furthermore accurate mineralogical information, that governs their refractive indices, is essential for scattering calculations. The radiative impacts of dust particles therefore depend on their morphology and mineralogy. Most of the present satellites consider the particle to be spherical while retrieving their optical properties. Some newly launched spacecraft instruments such as MISR accounts for non spherical nature by including spheroid particles in its retrieval algorithm . Clearly there exits a need for improvement in dust model used in retrieval algorithm to account for their sharp edges together with their index of refraction based on the latest chemical composition at the sensing wavelengths. To the best of our knowledge no such attempt has been made to calculate the optical properties of dust particles over the Thar desert. In this study, the optical properties of mineral dust of the Thar desert has been modeled using T-matrix method with realistic dust shapes based on Scanning Electron Microscope images of the dust over the desert with particle size ranging from 0.1-1.0 ìm at wavelengths spanning from ultraviolet to near infrared (0.38-1.2ìm). Representative dust particles shapes considered are sphere, cylinder, spheroids and chebyshev together with realistic mineral dust composition. Mineralogical analysis of airborne dust over Northwest India has revealed the presence of only basic non-metallic minerals such as Quartz, Feldspar, Mica and Calcite, which posses negligible imaginary part of refractive index at considered wavelength domain, however, the subsequent dust sampling

  18. Advances in Mineral Dust Source Composition Measurement with Imaging Spectroscopy at the Salton Sea, CA

    NASA Astrophysics Data System (ADS)

    Green, R. O.; Realmuto, V. J.; Thompson, D. R.; Mahowald, N. M.; Pérez García-Pando, C.; Miller, R. L.; Clark, R. N.; Swayze, G. A.; Okin, G. S.

    2015-12-01

    Mineral dust emitted from the Earth's surface is a principal contributor to direct radiative forcing over the arid regions, where shifts in climate have a significant impact on agriculture, precipitation, and desert encroachment around the globe. Dust particles contribute to both positive and negative forcing, depending on the composition of the particles. Particle composition is a function of the surface mineralogy of dust source regions, but poor knowledge of surface mineralogy on regional to global scales limits the skill of Earth System models to predict shifts in regional climate around the globe. Earth System models include the source, emission, transport and deposition phases of the dust cycle. In addition to direct radiative forcing contributions, mineral dust impacts include indirect radiative forcing, modification of the albedo and melting rates of snow and ice, kinetics of tropospheric photochemistry, formation and deposition of acidic aerosols, supply of nutrients to aquatic and terrestrial ecosystems, and impact on human health and safety. We demonstrate the ability to map mineral dust source composition in the Salton Sea dust source region with imaging spectroscopy measurements acquired as part of the NASA HyspIRI preparatory airborne campaign. These new spectroscopically derived compositional measurements provide a six orders of magnitude improvement over current atlases for this dust source region and provide a pathfinder example for a remote measurement approach to address this critical dust composition gap for global Earth System models.

  19. Airborne infrared mineral mapping survey of Marysvale, Utah

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.

    1982-01-01

    Infrared spectroradiometer survey results from flights over the Marysvale, Utah district show that hydrothermal alteration mineralogy can be mapped using very rapid and effective airborne techniques. The system detects alteration mineral absorption band intensities in the infrared spectral region with high sensitivity. The higher resolution spectral features and high spectral differences characteristic of the various clay and carbonate minerals are also readily identified by the instrument allowing the mineralogy to be mapped as well as the mineralization intensity.

  20. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2015-08-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of tranport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried higher concentration of pollution particles at intermediate altitude (1-3 km) than at elevated altitude (> 3 km), resulting in scattering Angstrom exponent up to 2.2 within the intermediate altitude. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate light absorption of the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00 ± 0.04. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assimilated to those of native dust in radiative transfer simulations, modeling studies and

  1. Size distribution and optical properties of mineral dust aerosols transported in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Cassola, F.; Mazzino, A.; Triquet, S.; Chevaillier, S.; Grand, N.; Bourrianne, T.; Momboisse, G.; Sellegri, K.; Schwarzenbock, A.; Freney, E.; Mallet, M.; Formenti, P.

    2016-02-01

    This study presents in situ aircraft measurements of Saharan mineral dust transported over the western Mediterranean basin in June-July 2013 during the ChArMEx/ADRIMED (the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) airborne campaign. Dust events differing in terms of source region (Algeria, Tunisia and Morocco), time of transport (1-5 days) and height of transport were sampled. Mineral dust were transported above the marine boundary layer, which conversely was dominated by pollution and marine aerosols. The dust vertical structure was extremely variable and characterized by either a single layer or a more complex and stratified structure with layers originating from different source regions. Mixing of mineral dust with pollution particles was observed depending on the height of transport of the dust layers. Dust layers carried a higher concentration of pollution particles below 3 km above sea level (a.s.l.) than above 3 km a.s.l., resulting in a scattering Ångström exponent up to 2.2 below 3 km a.s.l. However, the optical properties of the dust plumes remained practically unchanged with respect to values previously measured over source regions, regardless of the altitude. Moderate absorption of light by the dust plumes was observed with values of aerosol single scattering albedo at 530 nm ranging from 0.90 to 1.00. Concurrent calculations from the aerosol chemical composition revealed a negligible contribution of pollution particles to the absorption properties of the dust plumes that was due to a low contribution of refractory black carbon in regards to the fraction of dust and sulfate particles. This suggests that, even in the presence of moderate pollution, likely a persistent feature in the Mediterranean, the optical properties of the dust plumes could be assumed similar to those of native dust in radiative transfer simulations, modelling studies and satellite retrievals

  2. Pulmonary function of U. S. coal miners related to dust exposure estimates

    SciTech Connect

    Attfield, M.D.; Hodous, T.K. )

    1992-03-01

    This study of 7,139 U.S. coal miners used linear regression analysis to relate estimates of cumulative dust exposure to several pulmonary function variables measured during medical examinations undertaken between 1969 and 1971. The exposure data included newly derived cumulative dust exposure estimates for the period up to time of examination based on large data bases of underground airborne dust sampling measurements. Negative associations were found between measures of cumulative exposure and FEV1, FVC, and the FEV1/FVC ratio (p less than 0.001). In general, the relationships were similar to those reported for British coal miners. Overall, the results demonstrate an adverse effect of coal mine dust exposure on pulmonary function that occurs even in the absence of radiographically detected pneumoconiosis.

  3. Evidence of Mineral Dust Altering Cloud Microphysics and Precipitation

    NASA Technical Reports Server (NTRS)

    Min, Qilong; Li, Rui; Lin, Bing; Joseph, Everette; Wang, Shuyu; Hu, Yongxiang; Morris, Vernon; Chang, F.

    2008-01-01

    Multi-platform and multi-sensor observations are employed to investigate the impact of mineral dust on cloud microphysical and precipitation processes in mesoscale convective systems. It is clearly evident that for a given convection strength,small hydrometeors were more prevalent in the stratiform rain regions with dust than in those regions that were dust free. Evidence of abundant cloud ice particles in the dust sector, particularly at altitudes where heterogeneous nucleation process of mineral dust prevails, further supports the observed changes of precipitation. The consequences of the microphysical effects of the dust aerosols were to shift the precipitation size spectrum from heavy precipitation to light precipitation and ultimately suppressing precipitation.

  4. Examination of water spray airborne coal dust capture with three wetting agents

    PubMed Central

    Organiscak, J.A.

    2015-01-01

    Water spray applications are one of the principal means of controlling airborne respirable dust in coal mines. Since many coals are hydrophobic and not easily wetted by water, wetting agents can be added to the spray water in an effort to improve coal wetting and assist with dust capture. In order to study wetting agent effects on coal dust capture, laboratory experiments were conducted with three wetting agents used by the coal industry on -325 mesh sized Pocahontas No. 3 coal dust. Significant differences in coal dust sink times were observed among the three wetting agents at water mixture concentrations of 0.05%, 0.1% and 0.2%. The best wetting agent as identified by the coal dust sink test was only tested at the lowest 0.05% water mixture concentration and was found to have a negligible effect on spray airborne dust capture. Water spray airborne dust capture results for all three wetting agents tested at a 0.2% water mixture concentration showed that all three wetting agents exhibit similar but small improvements in dust capture efficiency as compared with water. These results indicate that the coal dust sink test may not be a good predictor for the capture of airborne dust. Additional research is needed to examine if the coal dust sink test is a better predictor of wetting agent dust suppression effects during cutting, loading, conveying and dumping of coal products by comparison to airborne dust capture from sprays. PMID:26251565

  5. 76 FR 12648 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-08

    ...' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors AGENCY: Mine Safety and... Continuous Personal Dust Monitors. The proposed rule would improve health protections for coal miners by... Occupational Exposure to Respirable Coal Mine Dust, the National Institute for Occupational Safety and...

  6. 75 FR 69617 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... addressing Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors. The proposed rule was published on October 19, 2010 (75 FR 64412) and is available on MSHA's Web...' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors AGENCY: Mine Safety...

  7. Mineral dust transport in the Arctic modelled with FLEXPART

    NASA Astrophysics Data System (ADS)

    Groot Zwaaftink, Christine; Grythe, Henrik; Stohl, Andreas

    2016-04-01

    Aeolian transport of mineral dust is suggested to play an important role in many processes. For instance, mineral aerosols affect the radiation balance of the atmosphere, and mineral deposits influence ice sheet mass balances and terrestrial and ocean ecosystems. While many efforts have been done to model global dust transport, relatively little attention has been given to mineral dust in the Arctic. Even though this region is more remote from the world's major dust sources and dust concentrations may be lower than elsewhere, effects of mineral dust on for instance the radiation balance can be highly relevant. Furthermore, there are substantial local sources of dust in or close to the Arctic (e.g., in Iceland), whose impact on Arctic dust concentrations has not been studied in detail. We therefore aim to estimate contributions of different source regions to mineral dust in the Arctic. We have developed a dust mobilization routine in combination with the Lagrangian dispersion model FLEXPART to make such estimates. The lack of details on soil properties in many areas requires a simple routine for global simulations. However, we have paid special attention to the dust sources on Iceland. The mobilization routine does account for topography, snow cover and soil moisture effects, in addition to meteorological parameters. FLEXPART, driven with operational meteorological data from European Centre for Medium-Range Weather Forecasts, was used to do a three-year global dust simulation for the years 2010 to 2012. We assess the model performance in terms of surface concentration and deposition at several locations spread over the globe. We will discuss how deposition and dust load patterns in the Arctic change throughout seasons based on the source of the dust. Important source regions for mineral dust found in the Arctic are not only the major desert areas, such as the Sahara, but also local bare-soil regions. From our model results, it appears that total dust load in the

  8. beta-(1,3)-Glucan exposure assessment by passive airborne dust sampling and new sensitive immunoassays.

    PubMed

    Noss, Ilka; Wouters, Inge M; Bezemer, Gillina; Metwali, Nervana; Sander, Ingrid; Raulf-Heimsoth, Monika; Heederik, Dick J J; Thorne, Peter S; Doekes, Gert

    2010-02-01

    Associations between house dust-associated beta-(1,3)-glucan exposure and airway inflammatory reactions have been reported, while such exposures in early childhood have been suggested to protect against asthma and wheezing. Most epidemiological studies have used reservoir dust samples and an inhibition enzyme immunoassay (EIA) for beta-(1,3)-glucan exposure assessment. The objective of this study was to develop inexpensive but highly sensitive enzyme immunoassays to measure airborne beta-(1,3)-glucans in low-exposure environments, like homes. Specificities of available anti-beta-(1,3)-glucan antibodies were defined by direct and inhibition experiments. Three suitable antibody combinations were selected for sandwich EIAs. beta-(1,3)-Glucans in passive airborne dust collected with an electrostatic dust fall collector (EDC) and floor dust from seven homes were measured with the three EIAs. Floor dust samples were additionally analyzed in the inhibition EIA. The sandwich EIAs were sensitive enough for airborne glucan measurement and showed different specificities for commercial glucans, while the beta-(1,3)-glucan levels in house dust samples correlated strongly. The feasibility of measuring glucans in airborne dust with the recently introduced EDC method was further investigated by selecting the most suitable of the three EIAs to measure and compare beta-(1,3)-glucan levels in the EDC and in floor and actively collected airborne dust samples of the previously performed EDC validation study. The EDC beta-(1,3)-glucan levels correlated moderately with beta-(1,3)-glucans in actively collected airborne dust and floor dust samples, while the glucan levels in the airborne dust and floor dust samples did not correlate. The combination of the newly developed beta-(1,3)-glucan sandwich EIA with EDC sampling now allows assessment in large-scale population studies of exposure to airborne beta-(1,3)-glucans in homes or other low-exposure environments.

  9. Advances in understanding mineral dust and boundary layer processes over the Sahara from Fennec aircraft observations

    NASA Astrophysics Data System (ADS)

    Ryder, C. L.; McQuaid, J. B.; Flamant, C.; Rosenberg, P. D.; Washington, R.; Brindley, H. E.; Highwood, E. J.; Marsham, J. H.; Parker, D. J.; Todd, M. C.; Banks, J. R.; Brooke, J. K.; Engelstaedter, S.; Estelles, V.; Formenti, P.; Garcia-Carreras, L.; Kocha, C.; Marenco, F.; Sodemann, H.; Allen, C. J. T.; Bourdon, A.; Bart, M.; Cavazos-Guerra, C.; Chevaillier, S.; Crosier, J.; Darbyshire, E.; Dean, A. R.; Dorsey, J. R.; Kent, J.; O'Sullivan, D.; Schepanski, K.; Szpek, K.; Trembath, J.; Woolley, A.

    2015-07-01

    The Fennec climate programme aims to improve understanding of the Saharan climate system through a synergy of observations and modelling. We present a description of the Fennec airborne observations during 2011 and 2012 over the remote Sahara (Mauritania and Mali) and the advances in the understanding of mineral dust and boundary layer processes they have provided. Aircraft instrumentation aboard the UK FAAM BAe146 and French SAFIRE (Service des Avions Français Instrumentés pour la Recherche en Environnement) Falcon 20 is described, with specific focus on instrumentation specially developed for and relevant to Saharan meteorology and dust. Flight locations, aims and associated meteorology are described. Examples and applications of aircraft measurements from the Fennec flights are presented, highlighting new scientific results delivered using a synergy of different instruments and aircraft. These include (1) the first airborne measurement of dust particles sizes of up to 300 microns and associated dust fluxes in the Saharan atmospheric boundary layer (SABL), (2) dust uplift from the breakdown of the nocturnal low-level jet before becoming visible in SEVIRI (Spinning Enhanced Visible Infra-Red Imager) satellite imagery, (3) vertical profiles of the unique vertical structure of turbulent fluxes in the SABL, (4) in situ observations of processes in SABL clouds showing dust acting as cloud condensation nuclei (CCN) and ice nuclei (IN) at -15 °C, (5) dual-aircraft observations of the SABL dynamics, thermodynamics and composition in the Saharan heat low region (SHL), (6) airborne observations of a dust storm associated with a cold pool (haboob) issued from deep convection over the Atlas Mountains, (7) the first airborne chemical composition measurements of dust in the SHL region with differing composition, sources (determined using Lagrangian backward trajectory calculations) and absorption properties between 2011 and 2012, (8) coincident ozone and dust surface area

  10. Microbial immigration across the Mediterranean via airborne dust.

    PubMed

    Rosselli, Riccardo; Fiamma, Maura; Deligios, Massimo; Pintus, Gabriella; Pellizzaro, Grazia; Canu, Annalisa; Duce, Pierpaolo; Squartini, Andrea; Muresu, Rosella; Cappuccinelli, Pietro

    2015-01-01

    Dust particles lifting and discharge from Africa to Europe is a recurring phenomenon linked to air circulation conditions. The possibility that microorganisms are conveyed across distances entails important consequences in terms of biosafety and pathogens spread. Using culture independent DNA-based analyses via next generation sequencing of the 16 S genes from the airborne metagenome, the atmospheric microbial community was characterized and the hypothesis was tested that shifts in species diversity could be recorded in relation to dust discharge. As sampling ground the island of Sardinia was chosen, being an ideal cornerstone within the Mediterranean and a crossroad of wind circulation amidst Europe and Africa. Samples were collected in two opposite coastal sites and in two different weather conditions comparing dust-conveying winds from Africa with a control situation with winds from Europe. A major conserved core microbiome was evidenced but increases in species richness and presence of specific taxa were nevertheless observed in relation to each wind regime. Taxa which can feature strains with clinical implications were also detected. The approach is reported as a recommended model monitoring procedure for early warning alerts in frameworks of biosafety against natural spread of clinical microbiota across countries as well as to prevent bacteriological warfare. PMID:26542754

  11. Microbial immigration across the Mediterranean via airborne dust

    PubMed Central

    Rosselli, Riccardo; Fiamma, Maura; Deligios, Massimo; Pintus, Gabriella; Pellizzaro, Grazia; Canu, Annalisa; Duce, Pierpaolo; Squartini, Andrea; Muresu, Rosella; Cappuccinelli, Pietro

    2015-01-01

    Dust particles lifting and discharge from Africa to Europe is a recurring phenomenon linked to air circulation conditions. The possibility that microorganisms are conveyed across distances entails important consequences in terms of biosafety and pathogens spread. Using culture independent DNA-based analyses via next generation sequencing of the 16 S genes from the airborne metagenome, the atmospheric microbial community was characterized and the hypothesis was tested that shifts in species diversity could be recorded in relation to dust discharge. As sampling ground the island of Sardinia was chosen, being an ideal cornerstone within the Mediterranean and a crossroad of wind circulation amidst Europe and Africa. Samples were collected in two opposite coastal sites and in two different weather conditions comparing dust-conveying winds from Africa with a control situation with winds from Europe. A major conserved core microbiome was evidenced but increases in species richness and presence of specific taxa were nevertheless observed in relation to each wind regime. Taxa which can feature strains with clinical implications were also detected. The approach is reported as a recommended model monitoring procedure for early warning alerts in frameworks of biosafety against natural spread of clinical microbiota across countries as well as to prevent bacteriological warfare. PMID:26542754

  12. Mineral dusts and radon in uranium mines

    SciTech Connect

    Abelson, P.H.

    1991-11-08

    The Environmental Protection Agency (EPA) continues to assert that radon is a major cause of lung cancer in this country. EPA is fostering a radon program that could entail huge financial and emotional costs while yielding negligible benefits to public health. Justification for the program was the occurrence of lung cancer in men exposed to huge amounts of radon, mineral dusts, and other lung irritants in uranium mines on the Colorado Plateau. Lung cancer has been reported in about 356 cigarette smokers and in about 25 nonsmokers. During the era of high radon levels, monitoring was sporadic. Conditions in only a small fraction of the mines were measured, and that on a few separate occasions. Later, cumulative exposure to radon was calculated on the basis of measurements involving only a tiny fraction of the miners. Some were exposed to more than 15,000 pCi/liter of radon and its products. The level in the average home is about 1.5 pCi/liter. In making extrapolations from mine to home, the assumption is made that residents are in their dwellings most of the time and that miners spend only 170 hours a month in the mine. Two major questionable assumptions are involved in extrapolations from high doses of radon in the mines to low doses in homes. One is that no threshold is involved; that is, that humans have no remediation mechanism for {alpha} particle damages. There is evidence to the contrary. The most unrealistic assumption is that heavy exposure to silica has no effect on inducing lung cancer. Many studies have shown that silica dust causes lung cancer in animals. Exposure of human culture cells to silica has resulted in formation of neoplastic tissue. EPA has no solid evidence that exposures to 4 pCi/liter of radon causes lung cancer in either smokers or nonsmokers. Indeed, there is abundant evidence to the contrary in the fact that in states with high levels of radon, inhabitants have less lung cancer than those in states with low levels.

  13. Health effects of particulate air pollution and airborne desert dust

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Pozzer, A.; Giannadaki, D.; Fnais, M.

    2013-12-01

    Air pollution by fine particulate matter (PM2.5) has increased strongly with industrialization and urbanization. In the past decades this increase has taken place at a particularly high pace in South and East Asia. We estimate the premature mortality and the years of human life lost (YLL) caused by anthropogenic PM2.5 and airborne desert dust (DU2.5) on regional and national scales (Giannadaki et al., 2013; Lelieveld et al., 2013). This is based on high-resolution global model calculations that resolve urban and industrial regions in relatively great detail. We apply an epidemiological health impact function and find that especially in large countries with extensive suburban and rural populations, air pollution-induced mortality rates have been underestimated given that previous studies largely focused on the urban environment. We calculate a global premature mortality by anthropogenic aerosols of 2.2 million/year (YLL ≈ 16 million/year) due to lung cancer and cardiopulmonary disease. High mortality rates by PM2.5 are found in China, India, Bangladesh, Pakistan and Indonesia. Desert dust DU2.5 aerosols add about 0.4 million/year (YLL ≈ 3.6 million/year). Particularly significant mortality rates by DU2.5 occur in Pakistan, China and India. The estimated global mean per capita mortality caused by airborne particulates is about 0.1%/year (about two thirds of that caused by tobacco smoking). We show that the highest premature mortality rates are found in the Southeast Asia and Western Pacific regions (about 25% and 46% of the global rate, respectively) where more than a dozen of the most highly polluted megacities are located. References: Giannadaki, D., A. Pozzer, and J. Lelieveld, Modeled global effects of airborne desert dust on air quality and premature mortality, Atmos. Chem. Phys. Discuss. (submitted), 2013. Lelieveld, J., C. Barlas, D. Giannadaki, and A. Pozzer, Model calculated global, regional and megacity premature mortality due to air pollution by ozone

  14. Effect of an electrostatic space charge system on airborne dust and subsequent potential transmission of microorganisms to broiler breeder pullets by airborne dust.

    PubMed

    Richardson, L J; Mitchell, B W; Wilson, J L; Hofacre, C L

    2003-01-01

    High levels of dust and microorganisms are known to be associated with animal confinement rearing facilities. Many of the microorganisms are carried by dust particles, thus providing an excellent vector for horizontal disease transmission between birds. Two environmentally controlled rooms containing female broiler breeder pullets (n = 300) were used to evaluate the effectiveness of an electrostatic space charge system (ESCS) in reducing airborne dust and gram-negative bacteria levels over an 8-wk period (starting when the birds were 10 wk old). The ESCS was used to evaluate the effectiveness of reducing airborne microorganism levels by charging airborne dust particles and causing the particles to be attracted to grounded surfaces (i.e., walls, floor, equipment). The use of the ESCS resulted in a 64% mean reduction in gram-negative bacteria. Airborne dust levels were reduced an average of 37% over a 1-wk period in the experimental room compared with the control room on the basis of samples taken every 10 min. The reductions of airborne dust and bacteria in this study are comparable with earlier results obtained with the ESCS in commercial hatching cabinets and experimental caged layer rooms, suggesting the system could also be applied to other types of enclosed animal housing. PMID:12713167

  15. [Occurrence of molds in airborne dusts in poultry farms].

    PubMed

    Gemeinhardt, H; Wallenstein, G

    1985-01-01

    To reach conclusions in terms of industrial hygiene, mycological samples were taken in modern poultry farms between 1979 and 1981. Sedimentation plates, the Krotow slit collector and the SPG-10 airborne dust sampler were used to determine the mould content of the air. The lowest germ counts were made in cage systems, while somewhat higher numbers were recorded among adult bids kept in the floor systems. Unexpectedly high numbers of mould germs were found in the air of large poultry houses where chickens were reared on relatively fresh litter. The fungus genera Penicillium and Cladosporium and, in one case, the species Scopulariopsis brevicaulis were predominant on old litter in both the floor and the cage system, whereas moulds of the Aspergillus group (Aspergillus candidus and A. versicolor) were additionally existent on fresh straw layers.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  17. Properties of transported African mineral dust aerosols in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Chevaillier, Servanne; Gaimoz, Cécile; Grand, Noel; Triquet, Sylvain; Zapf, Pascal; Loisil, Rodrigue; Bourrianne, Thierry; Freney, Evelyn; Dupuy, Regis; Sellegri, Karine; Schwarzenbock, Alfons; Torres, Benjamin; Mallet, Marc; Cassola, Federico; Prati, Paolo; Formenti, Paola

    2015-04-01

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

  18. 76 FR 25277 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-04

    ... FR 64412), MSHA published a proposed rule, Lowering Miners' Exposure to Respirable Coal Mine Dust... the proposed rule. The proposal was published on October 19, 2010 (75 FR 64412). DATES: All comments...' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors AGENCY: Mine Safety...

  19. Identifying sources of aeolian mineral dust: Present and past

    USGS Publications Warehouse

    Muhs, Daniel R; Prospero, Joseph M; Baddock, Matthew C; Gill, Thomas E

    2014-01-01

    Aeolian mineral dust is an important component of the Earth’s environmental systems, playing roles in the planetary radiation balance, as a source of fertilizer for biota in both terrestrial and marine realms and as an archive for understanding atmospheric circulation and paleoclimate in the geologic past. Crucial to understanding all of these roles of dust is the identification of dust sources. Here we review the methods used to identify dust sources active at present and in the past. Contemporary dust sources, produced by both glaciogenic and non-glaciogenic processes, can be readily identified by the use of Earth-orbiting satellites. These data show that present dust sources are concentrated in a global dust belt that encompasses large topographic basins in low-latitude arid and semiarid regions. Geomorphic studies indicate that specific point sources for dust in this zone include dry or ephemeral lakes, intermittent stream courses, dune fields, and some bedrock surfaces. Back-trajectory analyses are also used to identify dust sources, through modeling of wind fields and the movement of air parcels over periods of several days. Identification of dust sources from the past requires novel approaches that are part of the geologic toolbox of provenance studies. Identification of most dust sources of the past requires the use of physical, mineralogical, geochemical, and isotopic analyses of dust deposits. Physical properties include systematic spatial changes in dust deposit thickness and particle size away from a source. Mineralogy and geochemistry can pinpoint dust sources by clay mineral ratios and Sc-Th-La abundances, respectively. The most commonly used isotopic methods utilize isotopes of Nd, Sr, and Pb and have been applied extensively in dust archives of deep-sea cores, ice cores, and loess. All these methods have shown that dust sources have changed over time, with far more abundant dust supplies existing during glacial periods. Greater dust supplies in

  20. Effects of mineral dust on global atmospheric nitrate concentrations

    NASA Astrophysics Data System (ADS)

    Karydis, V. A.; Tsimpidi, A. P.; Pozzer, A.; Astitha, M.; Lelieveld, J.

    2016-02-01

    This study assesses the chemical composition and global aerosol load of the major inorganic aerosol components, focusing on mineral dust and aerosol nitrate. The mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are included in the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers K+, Ca2+, Mg2+, NH4+, Na+, SO42-, NO3-, Cl-, and H2O aerosol components. Emissions of mineral dust are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. Presence of metallic ions can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The model simulates highest fine aerosol nitrate concentration over urban and industrialized areas (1-3 µg m-3), while coarse aerosol nitrate is highest close to deserts (1-4 µg m-3). The influence of mineral dust on nitrate formation extends across southern Europe, western USA, and northeastern China. The tropospheric burden of aerosol nitrate increases by 44 % when considering interactions of nitrate with mineral dust. The calculated global average nitrate aerosol concentration near the surface increases by 36 %, while the coarse- and fine-mode concentrations of nitrate increase by 53 and 21 %, respectively. Other inorganic aerosol components are affected by reactive dust components as well (e.g., the tropospheric burden of chloride increases by 9 %, ammonium decreases by 41 %, and sulfate increases by 7 %). Sensitivity tests show that nitrate aerosol is most sensitive to the chemical composition of the emitted mineral dust, followed by the soil size distribution of dust particles, the magnitude of the mineral dust emissions, and the aerosol state assumption.

  1. Systematic Relationships Between Lidar Observables And Sizes And Mineral Composition Of Dust Aerosols

    NASA Astrophysics Data System (ADS)

    van Diedenhoven, B.; Perlwitz, J. P.; Fridlind, A. M.; Chowdhary, J.; Cairns, B.; Stangl, A. J.

    2015-12-01

    The physical and chemical properties of soil dust aerosol particles fundamentally affect their interaction with climate, including shortwave absorption and radiative forcing, nucleation of cloud droplets and ice crystals, heterogeneous formation of sulfates and nitrates on the surface of dust particles, and atmospheric processing of iron into bioavailable forms that increase the productivity of marine phytoplankton. Lidar measurements, such as extinction-to-backscatter, color and depolarization ratios, are frequently used to distinguish between aerosol types with different physical and chemical properties. The chemical composition of aerosol particles determines their complex refractive index, hence affecting their backscattering properties. Here we present a study on how dust aerosol backscattering and depolarization properties at wavelengths of 355, 532 and 1064 nm are related to size and complex refractive index, which varies with the mineral composition of the dust. Dust aerosols are represented by collections of spheroids with a range of prolate and oblate aspect ratios and their optical properties are obtained using T-matrix calculations. We find simple, systematic relationships between lidar observables and the dust size and complex refractive index that may aid the use of space-based or airborne lidars for direct retrieval of dust properties or for the evaluation of chemical transport models using forward simulated lidar variables. In addition, we present first results on the spatial variation of forward-simulated lidar variables based on a dust model that accounts for the atmospheric cycle of eight different mineral types plus internal mixtures of seven mineral types with iron oxides, which was recently implemented in the NASA GISS Earth System ModelE2.

  2. Systematic Relationships Between Lidar Observables and Sizes And Mineral Composition Of Dust Aerosols

    NASA Technical Reports Server (NTRS)

    Van Diedenhoven, Bastiaan; Stangl, Alexander; Perlwitz, Jan; Fridlind, Ann M.; Chowdhary, Jacek; Cairns, Brian

    2015-01-01

    The physical and chemical properties of soil dust aerosol particles fundamentally affect their interaction with climate, including shortwave absorption and radiative forcing, nucleation of cloud droplets and ice crystals, heterogeneous formation of sulfates and nitrates on the surface of dust particles, and atmospheric processing of iron into bioavailable forms that increase the productivity of marine phytoplankton. Lidar measurements, such as extinction-to-backscatter, color and depolarization ratios, are frequently used to distinguish between aerosol types with different physical and chemical properties. The chemical composition of aerosol particles determines their complex refractive index, hence affecting their backscattering properties. Here we present a study on how dust aerosol backscattering and depolarization properties at wavelengths of 355, 532 and 1064 nm are related to size and complex refractive index, which varies with the mineral composition of the dust. Dust aerosols are represented by collections of spheroids with a range of prolate and oblate aspect ratios and their optical properties are obtained using T-matrix calculations. We find simple, systematic relationships between lidar observables and the dust size and complex refractive index that may aid the use of space-based or airborne lidars for direct retrieval of dust properties or for the evaluation of chemical transport models using forward simulated lidar variables. In addition, we present first results on the spatial variation of forward-simulated lidar variables based on a dust model that accounts for the atmospheric cycle of eight different mineral types plus internal mixtures of seven mineral types with iron oxides, which was recently implemented in the NASA GISS Earth System ModelE2.

  3. Long-range transport of mineral dust in the global atmosphere: Impact of African dust on the environment of the southeastern United States

    PubMed Central

    Prospero, Joseph M.

    1999-01-01

    Soil dust is a major constituent of airborne particles in the global atmosphere. Dust plumes frequently cover huge areas of the earth; they are one of the most prominent and commonly visible features in satellite imagery. Dust is believed to play a role in many biogeochemical processes, but the importance of dust in these processes is not well understood because of the dearth of information about the global distribution of dust and its physical, chemical, and mineralogical properties. This paper describes some features of the large-scale distribution of dust and identifies some of the geological characteristics of important source areas. The transport of dust from North Africa is presented as an example of possible long-range dust effects, and the impact of African dust on environmental processes in the western North Atlantic and the southeastern United States is assessed. Dust transported over long distances usually has a mass median diameter <10 μm. Small wind-borne soil particles show signs of extensive weathering; consequently, the physical and chemical properties of the particles will greatly depend on the weathering history in the source region and on the subsequent modifications that occur during transit in the atmosphere (typically a period of a week or more). To fully understand the role of dust in the environment and in human health, mineralogists will have to work closely with scientists in other disciplines to characterize the properties of mineral particles as an ensemble and as individual particles especially with regard to surface characteristics. PMID:10097049

  4. Long-Range Transport of Mineral Dust in the Global Atmosphere: Impact of African Dust on the Environment of the Southeastern United States

    NASA Astrophysics Data System (ADS)

    Prospero, Joseph M.

    1999-03-01

    Soil dust is a major constituent of airborne particles in the global atmosphere. Dust plumes frequently cover huge areas of the earth; they are one of the most prominent and commonly visible features in satellite imagery. Dust is believed to play a role in many biogeochemical processes, but the importance of dust in these processes is not well understood because of the dearth of information about the global distribution of dust and its physical, chemical, and mineralogical properties. This paper describes some features of the large-scale distribution of dust and identifies some of the geological characteristics of important source areas. The transport of dust from North Africa is presented as an example of possible long-range dust effects, and the impact of African dust on environmental processes in the western North Atlantic and the southeastern United States is assessed. Dust transported over long distances usually has a mass median diameter <10 μ m Small wind-borne soil particles show signs of extensive weathering; consequently, the physical and chemical properties of the particles will greatly depend on the weathering history in the source region and on the subsequent modifications that occur during transit in the atmosphere (typically a period of a week or more). To fully understand the role of dust in the environment and in human health, mineralogists will have to work closely with scientists in other disciplines to characterize the properties of mineral particles as an ensemble and as individual particles especially with regard to surface characteristics.

  5. MicroMED: a dust particle counter for the characterization of airborne dust close to the surface of Mars

    NASA Astrophysics Data System (ADS)

    Cozzolino, Fabio; Esposito, Francesca; Molfese, Cesare; Cortecchia, Fausto; Saggin, Bortolino; D'amato, Francesco

    2015-04-01

    Monitoring of airborne dust is very important in planetary climatology. Indeed, dust absorbs and scatter solar and thermal radiation, severely affecting atmospheric thermal structure, balance and dynamics (in terms of circulations). Wind-driven blowing of sand and dust is also responsible for shaping planetary surfaces through the formation of sand dunes and ripples, the erosion of rocks, and the creation and transport of soil particles. Dust is permanently present in the atmosphere of Mars and its amount varies with seasons. During regional or global dust storms, more than 80% of the incoming sunlight is absorbed by dust causing an intense atmospheric heating. Airborne dust is therefore a crucial climate component on Mars which impacts atmospheric circulations at all scales. Main dust parameters influencing the atmosphere heating are size distribution, abundance, albedo, single scattering phase function, imaginary part of the index of refraction. Moreover, major improvements of Mars climate models require, in addition to the standard meteorological parameters, quantitative information about dust lifting, transport and removal mechanisms. In this context, two major quantities need to be measured for the dust source to be understood: surface flux and granulometry. While many observations have constrained the size distribution of the dust haze seen from the orbit, it is still not known what the primary airborne dust (e.g. the recently lifted dust) is made of, size-wise. MicroMED has been designed to fill this gap. It will measure the abundance and size distribution of dust, not in the atmospheric column, but close to the surface, where dust is lifted, so to be able to monitor dust injection into the atmosphere. This has never been performed in Mars and other planets exploration. MicroMED is an Optical Particle Counter, analyzing light scattered from single dust particles to measure their size and abundance. A proper fluid-dynamic system, including a pump and a

  6. New directions: Mineral dust and ozone - Heterogeneous chemistry

    NASA Astrophysics Data System (ADS)

    Ramachandran, S.

    2015-04-01

    Aerosols, the tiny solid or liquid particles suspended in air and produced from natural sources and anthropogenic activities, continue to contribute the largest uncertainty to radiative forcing (IPCC, 2013). Aerosol particles give rise to radiative forcing directly through scattering and absorption of solar and infrared radiation in the atmosphere. Aerosols also give rise to indirect radiative forcing by modifying the cloud optical properties and lifetimes. Among the aerosol species mineral dust and black carbon cause a warming (positive forcing) while sulphate and sea salt cause a cooling (negative forcing) of the Earth-atmosphere system. In tropics and sub-tropics mineral dust is a major contributor to aerosol loading and optical thickness. The global source strength of dust aerosol varies significantly on spatial and temporal scales. The source regions of dust are mainly deserts, dry lake beds, and semi-arid regions, in addition to drier regions where vegetation has been reduced or soil surfaces that are disturbed by man made activities. Anthropogenic activities mainly related to agriculture such as harvesting, ploughing, overgrazing, and cement production and transport also produce mineral dust. An estimated 2500 terragram (Tg, 1012 g) of mineral dust is emitted into the atmosphere per year, and dominates the aerosol mass over continental regions in south Asia and China accounting for ∼35% of the total aerosol mass (IPCC, 2013). In India, dust is prevalent throughout the north and western India during the year and peaks during premonsoon season.

  7. Heterogeneous uptake of nitrogen dioxide on Chinese mineral dust.

    PubMed

    Zhou, Li; Wang, Weigang; Hou, Siqi; Tong, Shengrui; Ge, Maofa

    2015-12-01

    Mineral dust is one of the major aerosols in the atmosphere. To assess its impact on trace atmospheric gases, in this work we present a laboratory study of the effect of temperature on the heterogeneous reaction of NO2 on the surface of ambient Chinese dust over the temperature range from 258 to 313K. The results suggest that nitrogen dioxide could mainly be adsorbed on these types of Chinese mineral dust reversibly with little temperature dependence. Similar to a previous study on NO2 uptake on mineral aerosols, the uptake coefficients are mainly on the order of 10(-6) for the Chinese dust, when BET areas are taken into account. HONO was observed as a product, and its formation and decomposition on Chinese mineral dust during the uptake processes were also studied. The complete dataset from this study was compiled with previous literature determinations. Atmospheric implications of the heterogeneous reaction between NO2 and mineral dust are also discussed, in an effort to understand this important heterogeneous process.

  8. Trans boundary transport of pollutants by atmospheric mineral dust.

    PubMed

    Erel, Yigal; Dayan, Uri; Rabi, Reut; Rudich, Yinon; Stein, Mordechai

    2006-05-01

    The transport of anthropogenic pollution by desert dust in the Eastern Mediterranean region was studied by analyzing major and trace element composition, organic species, and Pb isotope ratios in suspended dust samples collected in Jerusalem, Israel. Dust storms in this region are associated with four distinct synoptic conditions (Red Sea Trough (RS), Eastern High (EH), Sharav Cyclone (SC), and Cold Depression (Cyprus low, CD)) that carry dust mostly from North African (SC, CD, EH) and Arabian and Syrian (RS, EH) deserts. Substantial contamination of dust particles by Pb, Cu, Zn, and Ni is observed, while other elements (Na, Ca, Mg, Mn, Sr, Rb, REE, U, and Th) display natural concentrations. Sequential extraction of the abovementioned elements from the dust samples shows that the carbonate and sorbed fractions contain most of the pollution, yet the Al-silicate fraction is also contaminated, implying that soils and sediments in the source terrains of the dust are already polluted. We identified the pollutant sources by using Pb isotopes. It appears that before the beginning of the dust storm, the pollutants in the collected samples are dominated by local sources but with the arrival of dust from North Africa, the proportion of foreign pollutants increases. Organic pollutants exhibit behavior similar and complementary to that of the inorganic tracers, attesting to the importance of anthropogenic-pollutant addition en route of the dust from its remote sources. Pollution of suspended dust is observed under all synoptic conditions, yet it appears that easterly winds carry higher proportions of local pollution and westerly winds carry pollution emitted in the Cairo basin. Therefore, pollution transport by mineral dust should be accounted for in environmental models and in assessing the health-related effects of mineral dust.

  9. Influence of coal type on water spray suppression of airborne respirable dust

    SciTech Connect

    Organiscak, J.A. ); Leon, M.H. )

    1994-08-01

    A laboratory study was conducted to investigate the water spray capture efficiency of airborne respirable dust generated from nine different bituminous coal seams. Experiments involved grinding a uniform coal sample mass, injecting the dust into a closed steady-state chamber, and measuring the aerosol's decay response when exposed to a hollow cone water spray. The amount of airborne dust generated from these differential coal types varied, but had similar particle size distributions. The spray knockdown efficiency was comparable among coal types, and the size distribution of the dust was uniformly reduced by the water spray. Since water spray capture efficiency remained essentially uniform, the dust concentration at the end of the spray period was a function of the amount of dust generated. Therefore, a particular water spray system used in different coal seams under identical operating conditions (seam height, airflow, water pressure and flow, mining practices, etc.) can be expected to remove airborne dust in a uniform manner. However, dust concentrations will likely vary around identical water spray control systems used in different underground mines because of the diversity in operating conditions and the amount of dust generated from different coal scams. 11 refs., 8 figs., 3 tabs.

  10. The nature and formation of aeolian mineral dust material

    NASA Astrophysics Data System (ADS)

    Smalley, Ian; O'hara-Dhand, Ken; McLaren, Sue

    2013-04-01

    Aeolian dust affects climate and records past climates. It has become a much studied material but there has been a certain lack of emphasis on the actual nature of the dust, and an even greater neglect of actual production mechanisms for dust particles. Huge amounts of dust may be raised from the Bodele depression and other parts of North Africa, and much of it may be carried across the North Atlantic to aid in soil formation in Brazil. But what does it consist of? We know that much of the Bodele dust is diatoms from old Lake Chad, but what of the lithological inorganic mineral content? A very crude division of aeolian dust into large dust(say around 20-50um) and small dust (2-5um)has been proposed. Much of the study of loess has been confused by the failure to make this distinction, and similar problems may arise in the study of the finer fractions of aeolian dust. Much aeolian material is clay-mineral based- formed from clay mineral aggregates(CMA), from lake bottom sediments. This can form large dust particles, as in parna in Australia, but also contributes largely to small long travel aerosolic dust. Another major contributor is the quartz fragment. The large dust for classic loess deposits is mostly quartz silt- and there is considerable discussion about the controls that affect quartz silt. There are some interesting modalities in the world of quartz particle sedimentology which need to be examined. Quartz sand (say 200-500um) is the key initiating material and the formation processes for quartz sand have a down-the-line effect on the formation of smaller particles. The central observation is the action of two processes- a eutectic-like reaction in the proto-rock granite which defines the essential nature of sand particles, and the high-low displacive crystallographic transformation which introduces tensile stresses into the quartz particle systems. The limited range of eutectic particle size means a limited range of tensile stresses. A neat combination of

  11. Size distributions of mineral aerosols and dust emission flux observed over Horqin Sandy Land area in northern China

    NASA Astrophysics Data System (ADS)

    Li, X.; Zhang, H. S.

    2013-01-01

    Size distribution of mineral aerosols is of primary importance in determining their residence time in atmosphere, transport patterns, removal mechanisms as well as their effects on climate and human health. This study aims to obtain dust particle size distribution and size-resolved dust emission flux under different weather conditions over a sandy land area in northern China (Horqin Sandy Land, Inner Mongolia), using the observational data from Horqin sandstorm monitoring station in the spring of 2010 and 2012. Dust (PM20) mass concentration was measured by a 10-stage quartz crystal microbalance (QCM) cascade impactor. The statistical results indicate that finer dust particles (r ≤ 1.0 μm) take a large proportion of all PM20 concentration under clear-day conditions, while coarser dust particles (r ≥ 2.5 μm) concentration increased under dust-day conditions, with the peak occurring between 4-7 μm. The dust particle size distributions during the pre-dust-emission and dust-emission periods of a dust event on 7 April 2012 have similar features to the statistical results. During the dust event, the magnitude of dust emission flux of all sizes increased about one or two orders (0.1-10 μg m-2 s-1) as u* increase from 0.54 to 1.29 m s-1. The maximum total F value was about 43.0 μg m-2 s-1 and the maximum size-resolved F(Ddi) is 12.3 μg m-2 s-1 in 0.3-0.45 μm size bin when u* is 1.29 m s-1. Dust advection has effects on airborne dust size distribution, making the proportion of dust particles of different sizes more uniform, as observed in a non-local dust event on 19 April 2012.

  12. Observation of nitrate coatings on atmospheric mineral dust particles

    NASA Astrophysics Data System (ADS)

    Li, W. J.; Shao, L. Y.

    2009-03-01

    Nitrate compounds have received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN) activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of ambient nitrate-coated mineral particles on an individual particle scale. In this study, sample collection was conducted during brown haze and dust episodes between 24 May and 21 June 2007 in Beijing, northern China. Sizes, morphologies, and compositions of 332 mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) microanalyses. Structures of some mineral particles were verified using selected-area electron diffraction (SAED). TEM observation indicates that approximately 90% of the collected mineral particles are covered by visible coatings in haze samples whereas only 5% are coated in the dust sample. 92% of the analyzed mineral particles are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The majority of coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with small amounts of sulfates and chlorides. These nitrate coatings are strongly correlated with the presence of alkaline mineral components (e.g., calcite and dolomite). CaSO4 particles with diameters from 10 to 500 nm were also detected in the coatings including Ca(NO3)2 and Mg(NO3)2. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3). Mineral particles that acquire hygroscopic nitrate coatings tend to be more spherical and larger, enhancing their light scattering and CCN activity, both of which have cooling effects on the climate.

  13. An evaluation of radiation and dust hazards at a mineral sand processing plant.

    PubMed

    Johnston, G

    1991-06-01

    This three-part article discusses the results of a 2-y study on radiation and dust hazards in a mineral sand processing plant involving: (1) evaluation of external gamma radiation levels and determination of isotopic composition of the different sand products; (2) evaluation of radiation carried in long-lived radioactive dust (LLRD) particles; (3) evaluation of Rn gas concentrations within the working environs of the plant. Gamma radiation levels had a mean value of approximately 40 nSv h-1, and monazite sand returned the highest activity concentrations of 0.16% and 3.4% for 238U and 232Th, respectively. Low volume gross respirable dust sampling revealed an average long-lived airborne alpha activity concentration of 0.07 +/- 0.02 Bq m-3 and an average dust mass concentration of 3.3 +/- 2 mg m-3. Gamma spectroscopy applied to high-volume air samples showed average airborne 232Th and 238U activities of 0.012 +/- 0.004 Bq m-3 and 0.005 +/- 0.002 Bq m-3, respectively, giving an airborne 232Th: 238U ratio of 2.4:1. Air sampling using a high volume, five-stage cascade impactor indicated an average activity median aerodynamic diameter (AMAD) of 3.2 microns with an associated average geometric standard deviation (GSD) of 2.8. Average radiation dose arising from the inhalation of LLRD was estimated to be 7 mSv per annum. CR-39 (polycarbonate plastic) nuclear track detectors indicated that Rn gas concentrations in the environs of the processing plant dry mill and main product warehouse ranged from 30 Bq m-3 to 220 Bq m-3, with an average value of 100 Bq m-3, which presents a possible inhaled dose from Rn daughters of 1.5 mSv y-1 (assuming an equilibrium ratio of 0.5).

  14. Modeling light scattering by mineral dust particles using spheroids

    NASA Astrophysics Data System (ADS)

    Merikallio, Sini; Nousiainen, Timo

    Suspended dust particles have a considerable influence on light scattering in both terrestrial and planetary atmospheres and can therefore have a large effect on the interpretation of remote sensing measurements. Assuming dust particles to be spherical is known to produce inaccurate results when modeling optical properties of real mineral dust particles. Yet this approximation is widely used for its simplicity. Here, we simulate light scattering by mineral dust particles using a distribution of model spheroids. This is done by comparing scattering matrices calculated from a dust optical database of Dubovik et al. [2006] with those measured in the laboratory by Volten et al. [2001]. Wavelengths of 441,6 nm and 632,8 nm and refractive indexes of Re = 1.55 -1.7 and Im = 0.001i -0.01i were adopted in this study. Overall, spheroids are found to fit the measurements significantly better than Mie spheres. Further, we confirm that the shape distribution parametrization developed in Nousiainen et al. (2006) significantly improves the accuracy of simulated single-scattering for small mineral dust particles. The spheroid scheme should therefore yield more reliable interpretations of remote sensing data from dusty planetary atmospheres. While the spheroidal scheme is superior to spheres in remote sensing applications, its performance is far from perfect especially for samples with large particles. Thus, additional advances are clearly possible. Further studies of the Martian atmosphere are currently under way. Dubovik et al. (2006) Application of spheroid models to account for aerosol particle nonspheric-ity in remote sensing of desert dust, JGR, Vol. 111, D11208 Volten et al. (2001) Scattering matrices of mineral aerosol particles at 441.6 nm and 632.8 nm, JGR, Vol. 106, No. D15, pp. 17375-17401 Nousiainen et al. (2006) Light scattering modeling of small feldspar aerosol particles using polyhedral prisms and spheroids, JQSRT 101, pp. 471-487

  15. Geochemical evidence for airborne dust additions to soils in Channel Islands National Park, California

    USGS Publications Warehouse

    Muhs, D.R.; Budahn, J.R.; Johnson, D.L.; Reheis, M.; Beann, J.; Skipp, G.; Fisher, E.; Jones, J.A.

    2008-01-01

    There is an increasing awareness that dust plays important roles in climate change, biogeochemical cycles, nutrient supply to ecosystems, and soil formation. In Channel Islands National Park, California, soils are clay-rich Vertisols or Alfisols and Mollisols with vertic properties. The soils are overlain by silt-rich mantles that contrast sharply with the underlying clay-rich horizons. Silt mantles contain minerals that are rare or absent in the volcanic rocks that dominate these islands. Immobile trace elements (Sc-Th-La and Ta-Nd-Cr) and rare-earth elements show that the basalt and andesite on the islands have a composition intermediate between upper-continental crust and oceanic crust. In contrast, the silt fractions and, to a lesser extent, clay fractions of the silt mantle have compositions closer to average upper-continental crust and very similar to Mojave Desert dust. Island shelves, exposed during the last glacial period, could have provided a source of eolian sediment for the silt mantles, but this is not supported by mineralogical data. We hypothesize that a more likely source for the silt-rich mantles is airborne dust from mainland California and Baja California, either from the Mojave Desert or from the continental shelf during glacial low stands of sea. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. The eolian silt mantles constitute an important medium of plant growth and provide evidence that abundant eolian silt and clay may be delivered to the eastern Pacific Ocean from inland desert sources. ?? 2007 Geological Society of America.

  16. Chemical Evolution of Mineral Dust and Its Impact on Radiative Forcing in East Asia during 2006-2010

    NASA Astrophysics Data System (ADS)

    Fu, J. S.; DONG, X.; Huang, K.

    2014-12-01

    Arid regions and deserts in China and Mongolia are two of the main terrestrial sources of airborne dust, with major contribution from Taklamakan and Gobi deserts which can travel to China, Japan, Taiwan and even across Pacific Ocean to US and around north hemisphere. While China has been one of the most rapid-developing countries during the past decade, it also contributes intensive anthropogenic emissions including SO2 and NOx. Critical uncertainties remain regarding the chemical transformation of dust components during the transport with reactions involving these anthropogenic pollutants, which may significantly alter the optical properties and size distribution of mineral dust, and finally affect regional climate. In this study, we implemented heterogeneous reactions for dust particles into the WRF/CMAQ modeling system, and investigate the chemical evolution of mineral dust during the transport pathway. Integrating the dust-blown scheme of CMAQ, we also probe into the inter-annual changes of dust emission from East Asia, and the radiative forcing changes due to dust particles for 5 consecutive years from 2006-2010.

  17. Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline

    USGS Publications Warehouse

    Griffin, Dale W.; Kubilay, Nilgün; Kocak, Mustafa; Gray, Mike A.; Borden, Timothy C.; Shinn, Eugene A.

    2007-01-01

    Between 18 March and 27 October 2002, 220 air samples were collected on 209 of 224 calendar days, on top of a coastal atmospheric research tower in Erdemli, Turkey. The volume of air filtered for each sample was 340 liters. Two hundred fifty-seven bacterial and 2598 fungal colony forming units (CFU) were enumerated from the samples using a low-nutrient agar. Ground-based dust measurements demonstrated that the region is routinely impacted by dust generated regionally and from North Africa and that the highest combined percent recovery of total CFU and African dust deposition occurred in the month of April (93.4% of CFU recovery and 91.1% of dust deposition occurred during African dust days versus no African dust present, for that month). A statistically significant correlation was observed (peak regional African dust months of March, April and May; rs=0.576, P=0.000) between an increase in the prevalence of microorganisms recovered from atmospheric samples on dust days (regional and African as determined by ground-based dust measurements), versus that observed on non-dust days. Given the prevalence of atmospherically suspended desert dust and microorganisms observed in this study, and that culture-based studies typically only recover a small fraction (

  18. Long-Term Variability of Airborne Asian Dust Observed from TOMS

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Hsu, N. C.; Seftor, C. J.; Holben, B. N.; Holben, B. N.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Recent studies suggest that airborne Asian dust may not only play an important role in the regional radiation budget, but also influence the air quality over North America through long-range transport. In this paper, we use satellite data to investigate the long-term variability of airborne Asian dust as well as the daily variation of the dust aerosol distribution. By combining the Total Ozone Mapping Spectrometer (TOMS) aerosol index with National Centers for Environmental Prediction (NCEP) wind data, our analysis shows a strong correlation between the generation of dust storms in the region and the passage of springtime weather fronts. This is consistent with earlier studies performed by other researchers. According to both the Nimbus-7 and Earth-Probe TOMS data the Takla Makan desert, the Gobi desert, and the and region of Inner Mongolia are major sources of the eastward-flowing airborne Asian dust. Heavily populated areas in eastern China (e.g., Beijing) are often on the primary path of the dust storms originating in these desert regions. The increasing desertification north of the Beijing region has served to exacerbate problems stemming from these storms. The time series derived from 20 years of TOMS aerosol index data shows the first significant satellite evidence of the atmospheric effect of increasing desertification, indicating that the amount of dust blown eastward has increased strongly during the past few years including the year 2000.

  19. Nanoparticulate mineral matter from basalt dust wastes.

    PubMed

    Dalmora, Adilson C; Ramos, Claudete G; Querol, Xavier; Kautzmann, Rubens M; Oliveira, Marcos L S; Taffarel, Silvio R; Moreno, Teresa; Silva, Luis F O

    2016-02-01

    Ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been the subject of some concern recently around the world for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the mining district of Nova Prata in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/(Energy Dispersive Spectroscopy) EDS/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM)/EDS and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3 and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition we have identified a number of trace metals such as Cd, Cu, Cr, Zn that are preferentially concentrated into the finer, inhalable, dust fraction and could so present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in typical BDW samples highlights the need to develop cleaning procedures to minimise exposure to these natural fertilizing basalt dust wastes and is thus of direct relevance to both the industrial sector of basalt mining and to agriculture in the region.

  20. Nanoparticulate mineral matter from basalt dust wastes.

    PubMed

    Dalmora, Adilson C; Ramos, Claudete G; Querol, Xavier; Kautzmann, Rubens M; Oliveira, Marcos L S; Taffarel, Silvio R; Moreno, Teresa; Silva, Luis F O

    2016-02-01

    Ultra-fine and nano-particles derived from basalt dust wastes (BDW) during "stonemeal" soil fertilizer application have been the subject of some concern recently around the world for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the mining district of Nova Prata in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/(Energy Dispersive Spectroscopy) EDS/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM)/EDS and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO2, Al2O3 and Fe2O3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition we have identified a number of trace metals such as Cd, Cu, Cr, Zn that are preferentially concentrated into the finer, inhalable, dust fraction and could so present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical composition in typical BDW samples highlights the need to develop cleaning procedures to minimise exposure to these natural fertilizing basalt dust wastes and is thus of direct relevance to both the industrial sector of basalt mining and to agriculture in the region. PMID:26551199

  1. Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, volume 73

    NASA Technical Reports Server (NTRS)

    Haas, Michael R. (Editor); Davidson, Jacqueline A. (Editor); Erickson, Edwin F. (Editor)

    1995-01-01

    This symposium was organized to review the science related to NASA's Airborne Astronomy Program on the occasion of the twentieth anniversary of the Kuiper Airborne Observatory (KAO). The theme selected, 'The Galactic Ecosystem: From Gas to Stars to Dust,' was considered to capture the underlying commonality of much of the research discussed. The 8 sessions were as follows: The Interstellar Medium; The Life Cycle of the ISM in Other Galaxies; Star and Planetary System Formation; Our Planetary System: The Solar System; The Enrichment of the Interstellar Medium; The Galactic Center: A Unique Region of the Galactic Ecosystem; Instrumentation for Airborne Astronomy; KAO History and Education; and Missions and the Future of Infrared Astronomy.

  2. Elemental composition of airborne dust in the Shale Shaker House during an offshore drilling operation.

    PubMed

    Hansen, A B; Larsen, E; Hansen, L V; Lyngsaae, M; Kunze, H

    1991-12-01

    During 2 days of an offshore drilling operation in the North Sea, 16 airborne dust samples from the atmosphere of the Shale Shaker House were collected onto filters. During this operation, drilling mud composed of a water slurry of barite (BaSO4) together with minor amounts of additives, among them chrome lignosulphonate and chrome lignite, was circulated between the borehole and the Shale Shaker House. The concentration of airborne dust in the atmosphere was determined and the elemental composition of the particles analysed by both PIXE (proton-induced X-ray emission) and ICP-MS (inductively coupled plasma-mass spectrometry). The total amount of dust collected varied from 0.04 to 1.41 mg m-3 with barium (Ba) as the single most abundant element. The open shale shakers turned out to be the major cause of generation of dust from the solid components of the drilling mud.

  3. Elemental composition of airborne dust in the Shale Shaker House during an offshore drilling operation.

    PubMed

    Hansen, A B; Larsen, E; Hansen, L V; Lyngsaae, M; Kunze, H

    1991-12-01

    During 2 days of an offshore drilling operation in the North Sea, 16 airborne dust samples from the atmosphere of the Shale Shaker House were collected onto filters. During this operation, drilling mud composed of a water slurry of barite (BaSO4) together with minor amounts of additives, among them chrome lignosulphonate and chrome lignite, was circulated between the borehole and the Shale Shaker House. The concentration of airborne dust in the atmosphere was determined and the elemental composition of the particles analysed by both PIXE (proton-induced X-ray emission) and ICP-MS (inductively coupled plasma-mass spectrometry). The total amount of dust collected varied from 0.04 to 1.41 mg m-3 with barium (Ba) as the single most abundant element. The open shale shakers turned out to be the major cause of generation of dust from the solid components of the drilling mud. PMID:1768013

  4. Dust from mineral extraction: regulation of emissions in England

    NASA Astrophysics Data System (ADS)

    Marker, Brian

    2013-04-01

    The United Kingdom, which includes England, has fairly high levels of rainfall but sporadic droughts occur especially in the east. Mineral working gives rise to dust. Concerns about dust soiling are major source of public objections to new minerals extraction operations. Dust emissions from mineral workings are a significant cause of public concern in the United Kingdom and are recognised as sources of health concerns and nuisance. Emissions are controlled through a number of complementary sets of regulations that are generally well observed by the industry and well enforced by the relevant public authorities. comprehensive system of regulation, based on European and national law, to deal with all aspects of these operations including pollution control, planning, occupational health and safety and statutory nuisances. Most minerals applications are subject to EIA which forms that basis for planning and environmental conditions and monitoring of operations. There are limit values on PM10 and PM2.5 in air, and for potentially harmful elements (PHEs) in soils and water, derived from European regulations but, as yet, no limit values for PHEs (other than radioactive materials) in air. Stakeholder engagement is encouraged so that members of the public can express concerns during minerals operations and operators can quickly deal with these. While some effects inevitably remain, the levels of dust emissions are kept low through good site design and management, proper use of machinery which is equipped to minimise emissions, and good training of the workforce. Operational sites are required to have dust monitoring equipment located outside the site boundary so that any emerging problems can be detected and addressed quickly.

  5. Changes in the Airborne Bacterial Community in Outdoor Environments following Asian Dust Events

    PubMed Central

    Yamaguchi, Nobuyasu; Park, Jonguk; Kodama, Makiko; Ichijo, Tomoaki; Baba, Takashi; Nasu, Masao

    2014-01-01

    Bacterial abundance and community compositions have been examined in aeolian dust in order to clarify their possible impacts on public health and ecosystems. The influence of transcontinentally transported bacterial cells on microbial communities in the outdoor environments of downwind areas should be determined because the rapid influx of a large amount of bacterial cells can disturb indigenous microbial ecosystems. In the present study, we analyzed bacteria in air samples (approximately 100 m3 d−1) that were collected on both Asian dust days and non-Asian dust days over 2 years (between November 2010 and July 2012). Changes in bacterial abundance and community composition were investigated based on their 16S rRNA gene amount and sequence diversity. Seasonal monitoring revealed that airborne bacterial abundance was more than 10-fold higher on severe dust days, while moderate dust events did not affect airborne bacterial abundance. A comparison of bacterial community compositions revealed that bacteria in Asian dust did not immediately disturb the airborne microbial community in areas 3,000–5,000 km downwind of dust source regions, even when a large amount of bacterial cells were transported by the atmospheric event. However, microbes in aeolian dust may have a greater impact on indigenous microbial communities in downwind areas near the dust source. Continuous temporal and spatial analyses from dust source regions to downwind regions (e.g., from the Gobi desert to China, Korea, Japan, and North America) will assist in estimating the impact of atmospherically transported bacteria on indigenous microbial ecosystems in downwind areas. PMID:24553107

  6. Analysis of airborne MAIS imaging spectrometric data for mineral exploration

    SciTech Connect

    Wang Jinnian; Zheng Lanfen; Tong Qingxi

    1996-11-01

    The high spectral resolution imaging spectrometric system made quantitative analysis and mapping of surface composition possible. The key issue will be the quantitative approach for analysis of surface parameters for imaging spectrometer data. This paper describes the methods and the stages of quantitative analysis. (1) Extracting surface reflectance from imaging spectrometer image. Lab. and inflight field measurements are conducted for calibration of imaging spectrometer data, and the atmospheric correction has also been used to obtain ground reflectance by using empirical line method and radiation transfer modeling. (2) Determining quantitative relationship between absorption band parameters from the imaging spectrometer data and chemical composition of minerals. (3) Spectral comparison between the spectra of spectral library and the spectra derived from the imagery. The wavelet analysis-based spectrum-matching techniques for quantitative analysis of imaging spectrometer data has beer, developed. Airborne MAIS imaging spectrometer data were used for analysis and the analysis results have been applied to the mineral and petroleum exploration in Tarim Basin area china. 8 refs., 8 figs.

  7. Using proximate analysis to characterize airborne dust generation from bituminous coals

    SciTech Connect

    Page, S.J.; Organiscak, J.A.

    2005-11-01

    Prolonged exposure to airborne respirable coal dust is responsible for coal workers pneumoconiosis (CWP), commonly called black lung. Health research studies have identified that the prevalence and severity of CWP are directly related to both the amount of dust exposure and the coal rank. The amount of airborne respirable dust (ARD) smaller than 10 micrometers generated from breakage of different coals varies widely. To investigate the cause, researchers for the National Institute for Occupational Safety and Health (NIOSH) have conducted experiments to identify the causes of airborne respirable dust liberation. Laboratory crushing experiments were conducted on a range of low to high volatile bituminous coals from eight mines. The results indicate that the proximate analysis of a coal sample can provide a very good indicator of the potential for a dust problem. For application to the coal mining, processing, and utilization industries, data from 977 US coal seams compiled by the Department of Energy (DoE) has been used to calculate this dust generation potential from an equation based on the NIOSH measured data. A simple procedure for this calculation is provided. 1 fig.

  8. Mineral dust exposure and free radical-mediated lung damage

    SciTech Connect

    Doelman, C.J.; Leurs, R.; Oosterom, W.C.; Bast, A. )

    1990-01-01

    Chronic exposure to several types of mineral dust particles induces an inflammatory reaction in the lung. Dust particles activate alveolar macrophages and prime leukocytes (neutrophils, eosinophils, and basophils), leading to an enhanced release of reactive oxygen species. Sometimes mineral dust particles also contain radicals. Reactive oxygen species (superoxide anion radical, hydrogen peroxide, hydroxyl radical, and singlet oxygen) may lead to tissue damage. These are able to break DNA strands, to destroy proteins, and to induce the process of lipid peroxidation. The effects of oxygen radicals on the beta-adrenergic and muscarinic receptor response of the guinea pig and rat tracheal strip are described. The beta-adrenergic receptor response appeared to be more susceptible to oxidative stress than the muscarinic receptor response. This may lead to an autonomic imbalance on exposure to oxygen radicals. The lipid peroxidation product 4-hydroxy-2,3-trans-nonenal diminished the beta-adrenergic responsiveness in guinea pig tracheal preparations. Histologic examinations indicated that at low concentrations of cumene hydroperoxide (10(-4) M) the epithelial layer of rat trachea was already destroyed, whereas no effect on the muscarinic response was found. Oxygen radical-mediated damage in lung tissue may lead to lung emphysema, hyperresponsiveness, and hypersensitivity. Pharmacotherapeutic interventions that prevent initiation or propagation of these free radical reactions may have a beneficial effect in mineral dust-associated lung disease. 70 references.

  9. Technical note: Mineralogical, chemical, morphological, and optical interrelationships of mineral dust re-suspensions

    NASA Astrophysics Data System (ADS)

    Engelbrecht, Johann P.; Moosmüller, Hans; Pincock, Samuel; Jayanty, R. K. M.; Lersch, Traci; Casuccio, Gary

    2016-08-01

    This paper promotes an understanding of the mineralogical, chemical, and physical interrelationships of re-suspended mineral dusts collected as grab samples from global dust sources. Surface soils were collected from arid regions, including the southwestern USA, Mali, Chad, Morocco, Canary Islands, Cabo Verde, Djibouti, Afghanistan, Iraq, Kuwait, Qatar, UAE, Serbia, China, Namibia, Botswana, Australia, and Chile. The < 38 µm sieved fraction of each sample was re-suspended in a chamber, from which the airborne mineral dust could be extracted, sampled, and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5 particulate mass fractions, an aerodynamic particle size analyzer, and a three-wavelength (405, 532, 781 nm) photoacoustic instrument with integrating reciprocal nephelometer for monitoring absorption and scattering coefficients during the dust re-suspension process. Filter sampling media included Teflon® membrane and quartz fiber filters for chemical analysis and Nuclepore® filters for individual particle analysis by scanning electron microscopy (SEM). The < 38 µm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the > 75, < 125 µm soil fractions were mineralogically assessed by optical microscopy. Presented here are results of the optical measurements, showing the interdependency of single-scattering albedos (SSA) at three different wavelengths and mineralogical content of the entrained dust samples. To explain the elevated concentrations of iron (Fe) and Fe / Al ratios in the soil re-suspensions, we propose that dust particles are to a large extent composed of nano-sized particles of micas, clays, metal oxides, and ions of potassium (K+), calcium (Ca2+), and sodium

  10. Mineralogical, chemical, and optical interrelationships of mineral dusts from desert source regions

    NASA Astrophysics Data System (ADS)

    Engelbrecht, J. P.; Moosmüller, H.; Pincock, S.; Jayanty, J.; Casuccio, G.

    2013-12-01

    The goal of the project was to provide information on the mineralogical, chemical and physical interrelationships of re-suspended mineral dust samples collected from global dust sources. Surface soil samples were previously collected from more than 64 desert sites, including the southwestern USA (12), Mali (3), Chad (3), Morocco (1), Canary Islands (8), Cape Verde (1), Djibouti (1), Afghanistan (3), Iraq (6), Kuwait (5), Qatar (1), UAE (1), Serbia (3), China (5), Namibia (3), Botswana (4), Australia (3), and Chile (1). The < 38 μm sieved fraction of each sample was re-suspended in an entrainment facility, from which the airborne mineral dust could be sampled and analyzed. Instruments integrated into the entrainment facility included two PM10 and two PM2.5 filter samplers, a beta attenuation gauge for the continuous measurement of PM10 and PM2.5 particulate mass fractions, an aerodynamic particle size (APS) analyzer, and a three wavelength (405, 532, 781nm) photoacoustic instrument with integrating reciprocal nephelometer for monitoring aerosol absorption and scattering coefficients during the re-suspension process. Filter sample media included Teflon membrane and quartz fiber filters for chemical analysis (71 species), and Nuclepore filters for individual particle analysis by Scanning Electron Microscopy (SEM). The < 38 μm sieved fractions were also analyzed by X-ray diffraction for their mineral content while the > 38 μm, < 125 μm fractions were further mineralogically characterized by optical microscopy. We will be presenting results on the optical measurements, showing the relationship between single scattering albedo (SSA) at three different wavelengths, and chemical as well as mineralogical content and interrelationships, of the entrained dust samples. Information from this data base will be available for research in global climate, remote sensing, visibility, and health (medical geology).

  11. Modification of Saharan Mineral Dust during Transport across the Atlantic Ocean - Overview and Results from the SALTRACE Field Experiment

    NASA Astrophysics Data System (ADS)

    Weinzierl, Bernadett; Ansmann, Albert; Reitebuch, Oliver; Freudenthaler, Volker; Müller, Thomas; Kandler, Konrad; Groß, Silke; Sauer, Daniel; Althausen, Dietrich; Toledano, Carlos

    2014-05-01

    At present one of the largest uncertainties in our understanding of global climate concerns the interaction of aerosols with clouds and atmospheric dynamics. In the climate system, mineral dust aerosol is of key importance, because mineral dust contributes to about half of the global annual particle emissions by mass. Although our understanding of the effects of mineral dust on the atmosphere and the climate improved during the past decade, many questions such as the change of the dust size distribution during transport across the Atlantic Ocean and the associated impact on the radiation budget, the role of wet and dry dust removal mechanisms during transport, and the complex interaction between mineral dust and clouds remain open. The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE: http://www.pa.op.dlr.de/saltrace) was conducted in June/July 2013 to investigate the transport and transformation of Saharan mineral dust during long-range transport from the Sahara across the Atlantic Ocean into the Caribbean. SALTRACE is a German initiative combining ground-based and airborne in-situ and lidar measurements with meteorological data, long-term measurements, satellite remote sensing and modeling which involved many national and international partners. During SALTRACE, the DLR Falcon research aircraft was based at Sal, Cape Verde, between 11 and 17 June 2013, and at Barbados between 18 June and 11 July 2013. The Falcon was equipped with a suite of in-situ instruments for the measurement of microphysical and optical aerosol properties, with sampling devices for offline particle analysis, with a nadir-looking 2-µm wind lidar, with dropsondes and instruments for standard meteorological parameters. Ground-based lidar and in-situ instruments were deployed in Cape Verde, Barbados and Puerto Rico. During SALTRACE, mineral dust from five dust outbreaks was studied by the Falcon research aircraft between Senegal, the Caribbean and Florida

  12. Measurement of mixed biomass burning and mineral dust aerosol in the thermal infrared

    NASA Astrophysics Data System (ADS)

    Koehler, C. H.; Trautmann, T.; Lindermeir, E.

    2009-03-01

    From January 19th to February 7th, 2008, we installed a Fourier transform infrared spectrometer (FTIR) at Praia Airport on the island of Santiago, Cape Verde. Our goal was to measure the combined radiative effect of biomass burning aerosol and mineral dust usually observed there during that time of the year, when mineral dust emerging from the Sahara mixes with biomass burning aerosol transported north-westwards from the Sahelian region. Our measurements were part of the Saharan Mineral Dwst Experiment 2 (SAMUM 2) funded by the German Research Foundation (DFG) as continuation of the SAMUM field experiment in Morocco in 2006. SAMUM 2 is a joint venture of several German research institutes and universities and included both ground based as well as airborne measurements with the DLR Falcon research aircraft. The ground based instrumentation included spectrometers for visible and thermal infrared downwelling radiation, sun photometers, LIDAR and particle impactors while the Falcon was equipped with LIDAR and several instruments for aerosol analysis and sample return. A comparison of the FTIR measurements with radiative transfer simulations yields the expected aerosol forcing in the atmospheric window region after application of a suitable calibration method.

  13. The application of performance standards to personal airborne dust samplers.

    PubMed

    Kenny, L C; Lidén, G

    1989-01-01

    This paper summarizes current proposals for the specification and testing of personal sampler performance, and discusses their implications for the precision of dust concentration estimates. A method of specifying the performance of a sampling instrument in terms of the range of masses it would collect from various dust clouds is proposed. Some of the practical difficulties which are likely to arise in the process of testing real samplers with respect to performance standards are discussed.

  14. Distribution of Atmospheric Mineral Dust across Dryland Ecosystems (Invited)

    NASA Astrophysics Data System (ADS)

    Reynolds, R. L.; Goldstein, H.; Miller, M. E.; Neff, J. C.; Fernandez, D.; Reheis, M. C.

    2010-12-01

    Deposited atmospheric dust in surface sediments of dry landscapes can be identified using geochemical, isotopic, mineralogical, and textural methods that provide compositional contrasts between surficial sediment and local bedrock. In some settings, detrital minerals that are present in surficial sediment but absent in nearby bedrock can be used as proxies for concentration of far-traveled dust. For example, silt-sized, titanium-bearing magnetite is found in silty sediment on high, isolated landforms underlain by Mesozoic and Paleozoic sandstone, which lack such magnetite, from the Mojave Desert eastward across the Colorado Plateau. Magnetite amounts within the top 10 cm of these sediments correlate (r2= 0.54) with amounts of potential plant nutrients, revealing the importance of mineral dust to fertility across ecosystems. Systematic eastward declines in magnetite (determined using magnetic susceptibility or isothermal remanent magnetization, IRM) and Ti indicate dominant dust sources from igneous terrain in the west. Variations in lead isotopes imply that most anthropogenic dust contributions are sourced from the west, consistent with the regional distribution of urban sources. Similar relations are found across gently sloping, dominantly sandy grassland surfaces that have undergone sediment sorting by aeolian and slope-wash processes. In undisturbed settings, fertility indicators and dust amounts (derived from IRM) correlate tightly (r2 as high as 0.96 between IRM and plant nutrients), and the dust amounts are significantly greater than for settings currently grazed by domestic livestock and even those at which grazing ceased 35 years ago. These results, complemented by other field and compositional studies, reveal that disturbance of dry, upland landscapes commonly promotes wind erosion, which then depletes surfaces of originally deposited dust, including aeolian magnetite. Declines in soil fertility, soil fines, and water-holding capacity in these settings can

  15. Radiative Energetics of Mineral Dust Aerosols from Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Hansell, Richard A.

    2011-01-01

    Airborne dust aerosols worldwide contribute a significant part to air quality problems and, to some extent, regional climatic issues (e.g., radiative forcing, hydrological cycle, and primary biological productivity in oceans). Evaluating the direct solar radiative effect of dust aerosols is relatively straightforward due in part to the relatively large SIN ratio in broadband irradiance measurements. The longwave (LW) impact, on the other hand, is rather difficult to ascertain since the measured dust signal level (approx.10 W/sq m) is on the same order as the instrumental uncertainties. Although the magnitude of the LW impact is much smaller than that of the shortwave (SW), it can still have a noticeable influence on the energy distribution of Earth-atmosphere system, particularly due to the strong light-absorptive properties commonly found in many terrestrial minerals. The current effort is part of an ongoing research study to perform a global assessment of dust direct aerosol radiative effects (DARE) during major field deployments of key dust source regions worldwide. In this work we present results stemming from two previous field deployments: the 2006 NASA African Monsoon Multidisciplinary Activities and the 2008 Asian Monsoon Years, both utilizing NASA Goddard's mobile ground-based facility. The former study focused on transported Saharan dust at Sal (16.73degN, 22.93degW), Cape Verde along the west coast of Africa while the latter focused on Asian dust at Zhangye (39.082degN, 100.276degE), China near the source between the Taklimakan and Gobi deserts. Due to the compelling variability in spatial and temporal scale of dust properties during field experiments, a deterministic I-D radiative transfer model constrained by local measurements (i.e., spectral photometry/interferometry and lidar for physical/microphysical, mineralogy, and single-scattering properties) is employed to evaluate dust's local instantaneous SW/LW DARE both at the surface and at the top of

  16. Modeling the processing of mineral iron during dust transport

    NASA Astrophysics Data System (ADS)

    Vogelsberg, Ulrike; Wolke, Ralf; Tilgner, Andreas; Tegen, Ina; Herrmann, Hartmut

    2014-05-01

    The Saharan desert and the Gobi desert are the main contributors to Aeolian desert dust, which is a major source of micronutrients to the remote ocean regions. Micronutrients, such as transition metals like iron or copper, are regarded essential for biological processes of different marine species. In this context recent studies have shown that soluble iron, since it is generally the most abundant transition metal in dust particles, has the ability to control marine productivity and thereby likely influence the CO2- budget. Nevertheless, the processing of desert dust leading to the release of soluble iron still lacks sufficient understanding since several factors control the solubilization process. Especially anthropogenic emissions are regarded to significantly add to the amount of soluble iron by acidification of dust particles or by the direct emission of soluble iron comprised, e.g. in coal fly ash. For the investigation of the dissolution process of iron that takes place during dust transportation the spectral air parcel model SPACCIM is used. A mechanism describing the precipitation and dissolution of mineral particles by heterogeneous surface reactions has been implemented. Trajectory properties were derived from COSMO-MUSCAT simulations or from re-analysis data by HYSPLIT. Differences in the chemical composition and the amount of anthropogenic and naturally emitted species on the North African continent and the highly industrialized region of South-East Asia have considerable impact on the acidification of the desert dust. Under this aspect, special cases of dust outbreaks of the Saharan desert and the Gobi desert are investigated and compared with focus on soluble iron produced.

  17. The impacts of mineral dust on organized mesoscale deep convection

    NASA Astrophysics Data System (ADS)

    Seigel, Robert Brian

    The overarching goal of this research is to investigate how mineral dust can impact organized deep moist convection using numerical modeling. This is achieved through four modeling studies that each address a different aspect of organized mesoscale DMC. The first study uses the Regional Atmospheric Modeling System (RAMS) to simulate a supercell storm in order to examine the pathways in which mineral dust is entrained into DMC. This is achieved by simulating a supercell within three commonly observed dust regimes. Results indicate that the supercell in EXP-BACKGROUND ingests large dust concentrations ahead of the rear-flank downdraft (RFD) cold pool. Conversely, dust lofted by the cold pool in EXP-STORM is ingested by the supercell in relatively small amounts via a narrow corridor generated by turbulent mixing between the RFD cold pool and ambient air. The addition of a convergence boundary in EXP-BOUNDARY is found to act as an additional source of dust for the supercell and represents the case between EXP-BACKGROUND and EXP-STORM. Results demonstrate the importance of using an appropriate dust parameterization when modeling DMC, especially within more arid regions. The second study utilizes an idealized simulation of a nocturnal squall line to assess and isolate the individual responses in a squall line that arise (1) from radiation, (2) from dust altering the microphysics, as well as (3) from the synergistic effects between (1) and (2). To accomplish these tasks, we again use RAMS set up as a cloud-resolving model (CRM). Results indicate that RADIATION acts to increase precipitation, intensify the cold pool, and enhance the mesoscale organization of the squall line due to radiation-induced changes in the microphysics that appear to initiate from cloud top cooling. Conversely, DUST MICRO decreases precipitation, weakens the cold pool, and weakens the mesoscale organization of the squall line due to an enhancement of the warm rain process. SYNERGY shows little

  18. The effect of airborne dust on astronomical polarization measurements

    NASA Astrophysics Data System (ADS)

    Bailey, Jeremy; Ulanowski, Z.; Lucas, P. W.; Hough, J. H.; Hirst, E.; Tamura, M.

    2008-05-01

    In the past, it has generally been assumed that polarization observations made with ground-based telescopes are unaffected by the passage of light through the Earth's atmosphere. Here, we report observations with a new high-sensitivity astronomical polarimeter (PlanetPol) made during a Saharan dust event over the La Palma observatory in 2005 May that show excess linear polarization in the horizontal direction due to the passage of the starlight through the dust. The polarization reached a maximum value of 4.8 × 10-5 at 56° zenith distance and varied over five nights in proportion to the change in dust optical depth. Polarization of transmitted light (dichroism) does not occur for spherical or randomly oriented non-spherical particles. Thus, these results imply that some fraction of the dust grain population aligns with a preferred orientation. We use T-matrix models to demonstrate that the observed polarization direction implies a vertical orientation for the long axis of the particles. We suggest a possible mechanism for vertical orientation resulting from the electric field in the atmosphere. These results will need to be taken into account in the design and use of future instruments for high-sensitivity astronomical polarimetry. The results also indicate possible new approaches to studying aerosol particles and their effects on the Earth's atmosphere.

  19. Controls on mineral dust emissions at four arid locations in the western USA

    NASA Astrophysics Data System (ADS)

    Engelbrecht, Johann P.; Gillies, John A.; Etyemezian, Vicken; Kuhns, Hampden; Baker, Sophie E.; Zhu, Dongzi; Nikolich, George; Kohl, Steven D.

    Dust emission measurements from unique military sources, including tracked and wheeled military vehicles, low flying rotary-winged aircraft, and artillery backblast, were conducted in the course of four field campaigns in 2005-2008, at Yuma Proving Ground (YPG) in Arizona (twice), Yakima Test Center (YTC) in Washington State, and Ft. Carson in Colorado. This paper reports on the observed relationships between levels of dust emission, and the mineralogy, particle size, and chemical composition of the surface sediment and associated airborne mineral dust. We propose a mechanism for the generation of fine particulate matter, providing an explanation for high emissions in certain regions. PM10 (particulate matter with aerodynamic diameter of <10 μm) and PM2.5 (particulate matter with aerodynamic diameter of <2.5 μm) filter as well as bulk samples were collected for laboratory analysis in the course of the field campaigns. Analytical techniques applied include X-ray diffraction, Scanning Electron Microscopy, laser particle size analysis, as well as X-ray fluorescence spectrometry, Ion Chromatography, and Automated Colorimetry. Previous work has shown YTC has higher dust emission factors than YPG and Ft. Carson. The results presented in this paper demonstrate that the high PM10 and PM2.5 emissions measured at YTC can be explained by the high silt and low clay content of the surface sediment, attributed to glacial loess. In the other test areas, the abrasion of microscopic clay and oxide coatings, from and by silicate mineral grains, is considered a factor in the generation of fine particulate matter.

  20. Airborne fungal and bacterial components in PM1 dust from biofuel plants.

    PubMed

    Madsen, Anne Mette; Schlünssen, Vivi; Olsen, Tina; Sigsgaard, Torben; Avci, Hediye

    2009-10-01

    Fungi grown in pure cultures produce DNA- or RNA-containing particles smaller than spore size (<1.5 microm). High exposures to fungi and bacteria are observed at biofuel plants. Airborne cultivable bacteria are often described to be present in clusters or associated with larger particles with an aerodynamic diameter (d(ae)) of 2-8 microm. In this study, we investigate whether airborne fungal components smaller than spore size are present in bioaerosols in working areas at biofuel plants. Furthermore, we measure the exposure to bacteria and fungal components in airborne particulate matter (PM) with a D(50) of 1 microm (called PM(1) dust). PM(1) was sampled using Triplex cyclones at a working area at 14 Danish biofuel plants. Millipore cassettes were used to sample 'total dust'. The PM(1) particles (29 samples) were analysed for content of 11 different components and the total dust was analysed for cultivable fungi, N-acetyl-beta-D-glucosaminidase (NAGase), and (1 --> 3)-beta-D-glucans. In the 29 PM(1) samples, cultivable fungi were found in six samples and with a median concentration below detection level. Using microscopy, fungal spores were identified in 22 samples. The components NAGase and (1 --> 3)-beta-D-glucans, which are mainly associated with fungi, were present in all PM(1) samples. Thermophilic actinomycetes were present in 23 of the 29 PM(1) samples [average = 739 colony-forming units (CFU) m(-3)]. Cultivable and 'total bacteria' were found in average concentrations of, respectively, 249 CFU m(-3) and 1.8 x 10(5) m(-3). DNA- and RNA-containing particles of different lengths were counted by microscopy and revealed a high concentration of particles with a length of 0.5-1.5 microm and only few particles >1.5 microm. The number of cultivable fungi and beta-glucan in the total dust correlated significantly with the number of DNA/RNA-containing particles with lengths of between 1.0 and 1.5 microm, with DNA/RNA-containing particles >1.5 microm, and with other

  1. Variations in the structure of airborne bacterial communities in a downwind area during an Asian dust (Kosa) event.

    PubMed

    Maki, Teruya; Puspitasari, Findya; Hara, Kazutaka; Yamada, Maromu; Kobayashi, Fumihisa; Hasegawa, Hiroshi; Iwasaka, Yasunobu

    2014-08-01

    Asian dust (Kosa) events transport airborne microorganisms that significantly impact biological ecosystems, human health, and ice-cloud formation in downwind areas. However, the composition and population dynamics of airborne bacteria have rarely been investigated in downwind areas during Kosa events. In this study, air samplings were sequentially performed at the top of a 10-m high building within the Kosa event arrival area (Kanazawa City, Japan) from May 1 to May 7, 2011, during a Kosa event. The particle concentrations of bacterial cells and mineral particles were ten-fold higher during the Kosa event than on non-Kosa event days. A 16S ribosomal DNA clone library prepared from the air samples primarily contained sequences from three phyla: Cyanobacteria, Firmicutes, and Alphaproteobacteria. The clones from Cyanobacteria were mainly from a marine type of Synechococcus species that was dominant during the first phase of the Kosa event and was continuously detected throughout the Kosa event. The clones from Alphaproteobacteria were mainly detected at the initial and final periods of the Kosa event, and phylogenetic analysis showed that their sequences clustered with those from a marine bacterial clade (the SAR clade) and Sphingomonas spp. During the middle of the Kosa event, the Firmicutes species Bacillus subtilis and Bacillus pumilus were predominant; these species are known to be predominant in the atmosphere above the Chinese desert, which is the source of the dust during Kosa events. The clones obtained after the Kosa event had finished were mainly from Bacillus megaterium, which is thought to originate from local terrestrial areas. Our results suggest that airborne bacterial communities at the ground level in areas affected by Kosa events change their species compositions during a Kosa event toward those containing terrestrial and pelagic bacteria transported from the Sea of Japan and the continental area of China by the Kosa event. PMID:24815557

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

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

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

  3. New Manganese Silicide Mineral Phase in an Interplanetary Dust Particle

    NASA Technical Reports Server (NTRS)

    Nakamura-Messenger, K.; Keller, L. P.; Clemett, S. J.; Jones, J. H.; Palma, R. L.; Pepin, R. O.; Kloeck, W.; Zolensky, M. E.; Messenger, S.

    2008-01-01

    Comet 26P/Grigg-Skjellerup was identified as a source of an Earth-crossing dust stream with low Earth-encounter velocities, with peak anticipated fluxes during April in 2003 and 2004 [1]. In response to this prediction, NASA performed dedicated stratospheric dust collections using high altitude aircraft to target potential interplanetary dust particles (IDPs) from this comet stream in April 2003. Several IDPs from this collection have shown unusually low noble gas abundances [2] consistent with the predicted short space exposure ages of Grigg-Skjellerup dust particles [1]. High abundances of large D enrichments [3] and presolar grains [4] in IDPs from this collection are also consistent with an origin from the comet Grigg-Skjellerup. Here we report a new mineral from one of the cluster IDPs of the "Grigg-Skjellerup" collection, L2055. Our report focuses on an unusual manganese-iron-chromium silicide phase that, to our knowledge, has not been observed previously in nature. This unique phase may also shed light on the genesis of the enigmatic low-Fe,Mn-enriched (LIME) olivine that has been previously reported in IDPs and meteorites [5].

  4. Clay minerals in primitive meteorites and interplanetary dust 1

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Keller, L. P.

    1991-01-01

    Many meteorites and interplanetary dust particles (IDPs) with primitive compositions contain significant amounts of phyllosilicate minerals, which are generally interpreted as evidence of protoplanetary aqueous alteration at an early period of the solar system. These meteorites are chondrites (near solar composition) of the carbonaceous and ordinary varieties. The former are subdivided (according to bulk composition and petrology) into CI, CM, CV, CO, CR, and ungrouped classes. IDPs are extraterrestrial particulates, collected in stratosphere, which have chemical compositions indicative of a primitive origin; they are typically distinct from the primitive meteorites. Characterization of phyllosilicates in these materials is a high priority because of the important physico-chemical information they hold. The most common phyllosilicates present in chondritic extraterrestrial materials are serpentine-group minerals, smectites, and micas. We discuss these phyllosilicates and describe the interpretation of their occurrence in meteorites and IDPs and what this indicates about history of their parent bodies, which are probably the hydrous asteroids.

  5. Exposure to airborne microorganisms, dust and endotoxin during processing of peppermint and chamomile herbs on farms.

    PubMed

    Skórska, Czesława; Sitkowska, Jolanta; Krysińska-Traczyk, Ewa; Cholewa, Grazyna; Dutkiewicz, Jacek

    2005-01-01

    The aim of this study was to determine the levels of microorganisms, dust and endotoxin in the air during processing of peppermint (Mentha piperita) and chamomile (Matricaria recutita) by herb farmers, and to examine the species composition of airborne microflora. Air samples were collected on glass fibre filters by use of personal samplers on 13 farms owned by herb cultivating farmers, located in Lublin province (eastern Poland). The concentrations of total viable microorganisms (bacteria + fungi) in the farm air during processing of peppermint herb were large, within a range from 895.1-6,015.8 x 10(3) cfu/m(3) (median 1,055.3 x 10(3) cfu/m(3)). During processing of chamomile herb they were much lower and varied within a range from 0.88-295.6 x 10(3) cfu/m(3) (median 27.3 x 10(3) cfu/m(3)). Gram-negative bacteria distinctly prevailed during processing of peppermint leaves, forming 46.4-88.5 % of the total airborne microflora. During processing of chamomile herb, Gram-negative bacteria were dominant at 3 out of 6 sampling sites forming 54.7-75.3 % of total microflora, whereas at the remaining 3 sites the most common were fungi forming 46.2-99.9 % of the total count. The species Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans ), having strong allergenic and endotoxic properties, distinctly prevailed among Gram-negative isolates. Among fungi, the most common species was Alternaria alternata. The concentrations of airborne dust and endotoxin determined on the examined herb farms were large. The concentrations of airborne dust during peppermint and chamomile processing ranged from 86.7-958.9 mg/m(3), and from 1.1-499.2 mg/m(3), respectively (medians 552.3 mg/m(3) and 12.3 mg/m(3)). The concentrations of airborne endotoxin determined during peppermint and chamomile processing were within a wide range 1.53-208.33 microg/m(3) and 0.005-2604.19 microg/m(3) respectively (medians 57.3 microg/m(3) and 0.96 microg/m(3)). In conclusion, farmers

  6. The role of mineral dust aerosols in polar amplification

    NASA Astrophysics Data System (ADS)

    Lambert, F.; Kug, J.; Park, R.; Jin, F.; Lee, J. H.

    2010-12-01

    During today’s global warming, as well as during glacial-interglacial changes, temperature increase is larger in polar areas than the global average, a phenomenon called “polar amplification”. Model studies suggest ice cap melting due to greenhouse gas induced temperature rise, and consequent decrease of albedo and enhanced oceanic and atmospheric heat transport, as the primary cause for this phenomenon in nowadays Arctic. However, the underlying causes for polar amplification on glacial-interglacial timescales are still unclear, especially in the Antarctic where sea ice coverage does not change as drastically as in the North. Recent results have shown that the temperature increase is not limited to the surface and that these changes can not be explained by snow and ice changes alone. Starting with dust flux measurements from ice cores in Greenland and Antarctica, we have estimated tropospheric concentrations using deposition velocities and vertical concentration profiles for Holocene and LGM conditions from the National Center for Atmospheric Research’s Community Climate System Model (CCSM3) and a 3-D global chemical transport model (GEOS-Chem). The radiative forcing due to mineral dust aerosols was then estimated using the GEOS-Chem model, based on the particle properties found in the ice. Preliminary results point towards positive forcing of dust because of the high albedo of the underlying ice sheets.

  7. Red Dawn: Characterizing Iron Oxide Minerals in Atmospheric Dust

    NASA Astrophysics Data System (ADS)

    Yauk, K.; Ottenfeld, C. F.; Reynolds, R. L.; Goldstein, H.; Cattle, S.; Berquo, T. S.; Moskowitz, B. M.

    2012-12-01

    Atmospheric dust is comprised of many components including small amounts of iron oxide minerals. Although the iron oxides make up a small weight percent of the bulk dust, they are important because of their roles in ocean fertilization, controls on climate, and as a potential health hazard to humans. Here we report on the iron oxide mineralogy in dust from a large dust storm, dubbed Red Dawn, which engulfed eastern Australia along a 3000 km front on 23 September 2009. Red Dawn originated from the lower Lake Eyre Basin of South Australia, western New South Wales (NSW) and southwestern Queensland and was the worst dust storm to have hit the city of Sydney in more than 60 years. Dust samples were collected from various locations across eastern Australia (Lake Cowal, Orange, Hornsby, Sydney) following the Red Dawn event. Our dust collection provides a good opportunity to study the physical and mineralogical properties of iron oxides from Red Dawn using a combination of reflectance spectroscopy, Mössbauer spectroscopy (MB), and magnetic measurements. Magnetization measurements from 20-400 K reveal that magnetite/maghemite, hematite and goethite are present in all samples with magnetite occurring in trace amounts (< 0.5wt%). However, the amount of magnetite/maghemite even in trace concentrations generally increases from Lake Cowal from west to east (0.01 to 0.29 wt%), with highest magnetite contents in the urban-Sydney sites. These observations indicate the additions of magnetite from local urban sources. Variable temperature Mössbauer spectroscopy (300 K and 4.2 K) indicate that goethite and hematite compose approximately 25-45 % of the Fe-bearing phases in the Orange and Lake Cowal samples. Goethite is more abundant than hematite in the Lake Cowal samples whereas the opposite is observed for Orange. Hematite is observed at both temperatures but goethite only at 4.2 K. The identification of goethite in Mössbauer analyses at low-temperature but not at room temperature

  8. Airborne dust transport to the eastern Pacific Ocean off southern California: Evidence from San Clemente Island

    USGS Publications Warehouse

    Muhs, D.R.; Budahn, J.; Reheis, M.; Beann, J.; Skipp, G.; Fisher, E.

    2007-01-01

    Islands are natural dust traps, and San Clemente Island, California, is a good example. Soils on marine terraces cut into Miocene andesite on this island are clay-rich Vertisols or Alfisols with vertic properties. These soils are overlain by silt-rich mantles, 5-20 cm thick, that contrast sharply with the underlying clay-rich subsoils. The silt mantles have a mineralogy that is distinct from the island bedrock. Silt mantles are rich in quartz, which is rare in the island andesite. The clay fraction of the silt mantles is dominated by mica, also absent from local andesite, and contrasts with the subsoils, dominated by smectite. Ternary plots of immobile trace elements (Sc-Th-La and Ta-Nd-Cr) show that the island andesite has a composition intermediate between average upper continental crust and average oceanic crust. In contrast, the silt and, to a lesser extent, clay fractions of the silt mantles have compositions closer to average upper continental crust. The silt mantles have particle size distributions similar to loess and Mojave Desert dust, but are coarser than long-range-transported Asian dust. We infer from these observations that the silt mantles are derived from airborne dust from the North American mainland, probably river valleys in the coastal mountains of southern California and/or the Mojave Desert. Although average winds are from the northwest in coastal California, easterly winds occur numerous times of the year when "Santa Ana" conditions prevail, caused by a high-pressure cell centered over the Great Basin. Examination of satellite imagery shows that easterly Santa Ana winds carry abundant dust to the eastern Pacific Ocean and the California Channel Islands. Airborne dust from mainland North America may be an important component of the offshore sediment budget in the easternmost Pacific Ocean, a finding of potential biogeochemical and climatic significance.

  9. Global Distributions of Mineral Dust Properties from SeaWiFS and MODIS: From Sources to Sinks

    NASA Technical Reports Server (NTRS)

    Hsu, N. Christina; Bettenhausen, C.; Sayer, A.

    2011-01-01

    The impact of natural and anthropogenic sources of mineral dust has gained increasing attention from scientific communities in recent years. Indeed, these airborne dust particles, once lifted over the source regions, can be transported out of the boundary layer into the free troposphere and can travel thousands of kilometers across the oceans resulting in important biogeochemical impacts on the ecosystem. Due to the relatively short lifetime (a few hours to about a week), the distributions of these mineral dust particles vary extensively in both space and time. Consequently, satellite observations are needed over both source and sink regions for continuous temporal and spatial sampling of aerosol properties. With the launch of SeaWiFS in 1997, Terra/MODIS in 1999, and Aqua/MODIS in 2002, high quality comprehensive aerosol climatology is becoming feasible for the first time. As a result of these unprecedented satellite data records, studies of the radiative and biogeochemical effects due to dust aerosols are now possible. In this study, we will show the comparisons of satellite retrieved aerosol optical thickness using Deep Blue algorithm with data from AERONET sunphotometers over desert and semi-desert regions as well as vegetated areas. Our results indicate reasonable agreements between these two. These new satellite products will allow scientists to determine quantitatively the aerosol properties near sources using high spatial resolution measurements from Sea WiFS and MODIS-like instruments. The multiyear satellite measurements since 1997 from Sea WiFS will be compared with those retrieved from MODIS and MISR, and will be utilized to investigate the interannual variability of source, pathway, and dust loading associated with the dust outbreaks over the entire globe. Finally, the trends observed over the last decade based upon the SeaWiFS time series in the amounts of tropospheric aerosols due to natural and anthropogenic sources (such as changes in the frequency

  10. NMMB/BSC-DUST: an online mineral dust atmospheric model from meso to global scales

    NASA Astrophysics Data System (ADS)

    Haustein, K.; Pérez, C.; Jorba, O.; Baldasano, J. M.; Janjic, Z.; Black, T.; Nickovic, S.

    2009-04-01

    While mineral dust distribution and effects are important at global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales. Most global dust models use prescribed wind fields provided by meteorological centers (e.g., NCEP and ECMWF) and their spatial resolution is currently never better than about 1°×1°. Regional dust models offer substantially higher resolution (10-20 km) and are typically coupled with weather forecast models that simulate processes that GCMs either cannot resolve or can resolve only poorly. These include internal circulation features such as the low-level nocturnal jet which is a crucial feature for dust emission in several dust ‘hot spot' sources in North Africa. Based on our modeling experience with the BSC-DREAM regional forecast model (http://www.bsc.es/projects/earthscience/DREAM/) we are currently implementing an improved mineral dust model [Pérez et al., 2008] coupled online with the new global/regional NMMB atmospheric model under development in NOAA/NCEP/EMC [Janjic, 2005]. The NMMB is an evolution of the operational WRF-NMME extending from meso to global scales. The NMMB will become the next-generation NCEP model for operational weather forecast in 2010. The corresponding unified non-hydrostatic dynamical core ranges from meso to global scale allowing regional and global simulations. It has got an add-on non-hydrostatic module and it is based on the Arakawa B-grid and hybrid pressure-sigma vertical coordinates. NMMB is fully embedded into the Earth System Modeling Framework (ESMF), treating dynamics and physics separately and coupling them easily within the ESMF structure. Our main goal is to provide global dust forecasts up to 7 days at mesoscale resolutions. New features of the model include a physically-based dust emission scheme after White [1979], Iversen and White [1982] and Marticorena and Bergametti [1995] that takes the effects of saltation and sandblasting into account

  11. Speciation of airborne dust from a nickel refinery roasting operation.

    PubMed

    Andersen, I; Berge, S R; Resmann, F

    1998-04-01

    Earlier work-related lung and nasal cancer studies included estimates of exposures to different nickel species in the refinery. Based on the metallurgy, only insoluble nickel was believed to be present around the roasters but mixed exposure was assumed in most areas, including the tankhouse. Occasional leaching tests of samples from the roaster area have indicated the presence of soluble nickel. This study reports on five parallel sets of dust samples collected from different floors with standard equipment and treated as follows. Two sets were leached with an ammonium citrate buffer at pH 4.4. Undissolved material was treated with HClO4/HNO3, evaporated to dryness and dissolved in HCl, Ni, Cu, Co, Fe, Se, and As were determined in both fractions. Water soluble Ni was found in all samples, ranging from 5-35%. Sulfate in the solutions correlated nearly stoichiometrically to the total metal content. The three remaining sets were investigated by, respectively, differential leaching, X-ray diffraction and scanning electron microscopy. The percentage of soluble nickel found by differential leaching corresponded well with those obtained by the simplified procedure. X-Ray diffraction analysis showed the presence of NiSO4.6H2O as well as oxides of Ni and Cu. This study indicates mixed exposures also in the roaster area. It also clearly indicates that basing exposure on the metallurgy alone can lead to serious misjudgements. The impact of this new information on the interpretation of cancer incidence at this refinery must await the analysis in an ongoing case-reference study. PMID:9684402

  12. Airborne and Grain Dust Fungal Community Compositions Are Shaped Regionally by Plant Genotypes and Farming Practices

    PubMed Central

    Pellissier, Loïc; Oppliger, Anne; Hirzel, Alexandre H.; Savova-Bianchi, Dessislava; Mbayo, Guilain; Mascher, Fabio; Kellenberger, Stefan

    2016-01-01

    Chronic exposure to airborne fungi has been associated with different respiratory symptoms and pathologies in occupational populations, such as grain workers. However, the homogeneity in the fungal species composition of these bioaerosols on a large geographical scale and the different drivers that shape these fungal communities remain unclear. In this study, the diversity of fungi in grain dust and in the aerosols released during harvesting was determined across 96 sites at a geographical scale of 560 km2 along an elevation gradient of 500 m by tag-encoded 454 pyrosequencing of the internal transcribed spacer (ITS) sequences. Associations between the structure of fungal communities in the grain dust and different abiotic (farming system, soil characteristics, and geographic and climatic parameters) and biotic (wheat cultivar and previous crop culture) factors were explored. These analyses revealed a strong relationship between the airborne and grain dust fungal communities and showed the presence of allergenic and mycotoxigenic species in most samples, which highlights the potential contribution of these fungal species to work-related respiratory symptoms of grain workers. The farming system was the major driver of the alpha and beta phylogenetic diversity values of fungal communities. In addition, elevation and soil CaCO3 concentrations shaped the alpha diversity, whereas wheat cultivar, cropping history, and the number of freezing days per year shaped the taxonomic beta diversity of these communities. PMID:26826229

  13. Airborne and Grain Dust Fungal Community Compositions Are Shaped Regionally by Plant Genotypes and Farming Practices.

    PubMed

    Pellissier, Loïc; Oppliger, Anne; Hirzel, Alexandre H; Savova-Bianchi, Dessislava; Mbayo, Guilain; Mascher, Fabio; Kellenberger, Stefan; Niculita-Hirzel, Hélène

    2016-04-01

    Chronic exposure to airborne fungi has been associated with different respiratory symptoms and pathologies in occupational populations, such as grain workers. However, the homogeneity in the fungal species composition of these bioaerosols on a large geographical scale and the different drivers that shape these fungal communities remain unclear. In this study, the diversity of fungi in grain dust and in the aerosols released during harvesting was determined across 96 sites at a geographical scale of 560 km(2) along an elevation gradient of 500 m by tag-encoded 454 pyrosequencing of the internal transcribed spacer (ITS) sequences. Associations between the structure of fungal communities in the grain dust and different abiotic (farming system, soil characteristics, and geographic and climatic parameters) and biotic (wheat cultivar and previous crop culture) factors were explored. These analyses revealed a strong relationship between the airborne and grain dust fungal communities and showed the presence of allergenic and mycotoxigenic species in most samples, which highlights the potential contribution of these fungal species to work-related respiratory symptoms of grain workers. The farming system was the major driver of the alpha and beta phylogenetic diversity values of fungal communities. In addition, elevation and soil CaCO3 concentrations shaped the alpha diversity, whereas wheat cultivar, cropping history, and the number of freezing days per year shaped the taxonomic beta diversity of these communities. PMID:26826229

  14. Analysis of Potentially Toxic Metals in Airborne Cement Dust Around Sagamu, Southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Gbadebo, A. M.; Bankole, O. D.

    This study analyzed the concentration levels of potentially toxic and harmful elements contained in the airborne cement dust generated in the vicinity and farther away 500 m in the conventional four cardinal directions from the West African Portland Cement Company (WAPCO) factory mill, Sagamu. The results indicated that the concentration range of these toxic elements fall between 40.0 and 280,000 μg g-1 in the cement dust samples. Also, the concentration range of these toxic elements in 1 L of air samples varies between 0.01 μg g-1 and 29.92 μg L-1. The results generally show elevated concentrations of all the elements when compared with USA threshold limit of particulate mental concentration (e.g., Pb (1.5 g m-3); Cd (0.004-0.026 g m-3) in the air. These elements in the airborne cement dusts may pose a great threat to the health of plants, animals and residents in and around the factory and also to workers and visitors to the factory.

  15. Interactions of Water with Mineral Dust Aerosol: Water Adsorption, Hygroscopicity, Cloud Condensation, and Ice Nucleation.

    PubMed

    Tang, Mingjin; Cziczo, Daniel J; Grassian, Vicki H

    2016-04-13

    Mineral dust aerosol is one of the major types of aerosol present in the troposphere. The molecular level interactions of water vapor with mineral dust are of global significance. Hygroscopicity, light scattering and absorption, heterogneous reactivity and the ability to form clouds are all related to water-dust interactions. In this review article, experimental techniques to probe water interactions with dust and theoretical frameworks to understand these interactions are discussed. A comprehensive overview of laboratory studies of water adsorption, hygroscopicity, cloud condensation, and ice nucleation of fresh and atmspherically aged mineral dust particles is provided. Finally, we relate laboratory studies and theoretical simulations that provide fundemental insights into these processes on the molecular level with field measurements that illustrate the atmospheric significance of these processes. Overall, the details of water interactions with mineral dust are covered from multiple perspectives in this review article. PMID:27015126

  16. Interactions of Water with Mineral Dust Aerosol: Water Adsorption, Hygroscopicity, Cloud Condensation, and Ice Nucleation.

    PubMed

    Tang, Mingjin; Cziczo, Daniel J; Grassian, Vicki H

    2016-04-13

    Mineral dust aerosol is one of the major types of aerosol present in the troposphere. The molecular level interactions of water vapor with mineral dust are of global significance. Hygroscopicity, light scattering and absorption, heterogneous reactivity and the ability to form clouds are all related to water-dust interactions. In this review article, experimental techniques to probe water interactions with dust and theoretical frameworks to understand these interactions are discussed. A comprehensive overview of laboratory studies of water adsorption, hygroscopicity, cloud condensation, and ice nucleation of fresh and atmspherically aged mineral dust particles is provided. Finally, we relate laboratory studies and theoretical simulations that provide fundemental insights into these processes on the molecular level with field measurements that illustrate the atmospheric significance of these processes. Overall, the details of water interactions with mineral dust are covered from multiple perspectives in this review article.

  17. Long-term airborne contamination studied by attic dust in an industrial area: Ajka, Hungary

    NASA Astrophysics Data System (ADS)

    Völgyesi, P.; Jordan, G.; Szabo, Cs.

    2012-04-01

    Heavy industrial activities such as mining, metal industry, coal fired power plants have produced large amount of by-products and wide-spread pollution, particularly in the period of centrally dictated economy after WWII, in Hungary. Several studies suggest that significant amount of these pollutants have been deposited in the urban environment. Nowadays, more than half of the world's population is living in urban areas and people spend almost 80% of their lives indoors in developed countries increasing human health risk due to contamination present in urban dwellings. Attic dust sampling was applied to determine the long-term airborne contamination load in the industrial town of Ajka (Hungary). There has been a high industrial activity in Ajka since the end of the 19th century. In addition to aluminum and alumina industry, coal mining, coal fired power plant and glass industry sites, generated numerous waste heaps which act as multi-contamination sources in the area. In October 2010 the Ajka red mud tailings pond failed and caused an accidental regional contamination of international significance. The major objective of this research was to study and map the spatial distribution of heavy metal contamination in airborne attic dust samples. At 27 sampling sites 30 attic dust samples were collected. Sampling strategy followed a grid-based stratified random sampling design. In each cell a house for attic dust sample collection was selected that was located the closest to a randomly generated point in the grid cell. The project area covers a 8x8 grid of 1x1 km cells with a total area of 64 km2. In order to represent long-term industrial pollution, houses with attics kept intact for at least 30-40 years were selected for sampling. Sampling included the collection of background samples remotely placed from the industrialized urban area. The concentration of the major and toxic elements (Al, Ca, Fe, K, Mg, Mn, Na, P, S, and As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Se, Sn

  18. Dust exposure and respiratory disease in U. S. coal miners

    SciTech Connect

    Seixas, N.S.

    1990-01-01

    This study examines the effectiveness of the dust standards set by the Coal Mine Health and Safety Act of 1969 in preventing obstructive lung disease by considering the exposure-response relationship in a group of miners whose exposure began in or after 1970 when the regulations took effect. Exposing-response relationships were examined among 1,270 miners from the National Study of Coal Workers' Pneumoconiosis. Cross-sectional and longitudinal associations between cumulative exposure and pulmonary function test results (FVC, FEV{sub 1}, and FEV{sub 1}/FVC) and respiratory symptoms were modeled using linear and logistic regression while controlling for smoking. The results over a 15 year exposure period indicated statistically significant positive associations of cumulative exposure with decrements in FEV{sub 1}, FEV{sub 1}/FVC, the likelihood of these indices being less than 80% of predicted, and symptoms, including chronic bronchitis, breathlessness and wheeze with shortness of breath. The estimated effect of exposure of FEV{sub 1} was 5.5 ml per mg/m{sup 3} -years which was substantially larger than previously reported estimates. However, examination of PFTs within five years of beginning work demonstrated a rapid initial exposure-related loss of both FVC and FEV{sub 1} and no additional exposure-related loss over the following 10 years. The results of the study suggest that exposure to coal mine dust at concentrations present since the CMHSA regulations were put into effect have not been completely successful in preventing respiratory effects. Determination of the long-term significance of the initial exposure-response relationship observed requires additional follow-up of this cohort.

  19. Sensory and other neurogenic effects of exposures to airborne office dust

    NASA Astrophysics Data System (ADS)

    Mølhave, L.; Kjærgaard, S. K.; Attermann, J.

    This Danish Office Dust Experiment investigated the response of 24 healthy non-sensitive adult subjects to exposure to normal office dust in the air (7 μg m -3 clean air, 136 and 390 μg m -3 TSP). The dust had no major identifiable specific reactive components. The exposure duration was 5 1/4 h and was arranged in a climate chamber in controlled atmospheric conditions. Measurements were made acutely at exposure onset, subacutely at exposure end and next day (late). As secondary aims the time course and threshold of any observed effect of the exposures, and the characteristics of any hyperresponding subgroup were investigated. In a questionnaire with 36 questions the dust exposures caused increased acute, subacute and late perceptions of reduced air quality, acute and subacute increased odor intensity, acute eye irritation, acute and late heavy head, subacute feeling of perspiration, and subacute general irritation. Cough increased subacutely during exposures. In addition, a performance test showed effects of dust exposures which also affected "Mood Scale" ratings. No effect was seen on an addition test for distraction, and objective measurements of skin humidity. The overall conclusion of the study is that healthy subjects without hypersensitivity reactions seem to respond to airborne house dust. The responses are both subjective sensory reactions and other neurogenic effects even at exposure levels within the range found in normal buildings. Some of the effects appeared acutely and decreased through adaptation while others increased during prolonged exposure and remained for more than 17 h after the exposure ended. The findings may indicate for this type of dust a threshold level for the dose-response relationships below 140 μg m -3.

  20. Global distribution of minerals in arid soils as lower boundary condition in dust models

    NASA Astrophysics Data System (ADS)

    Nickovic, Slobodan

    2010-05-01

    Mineral dust eroded from arid soils affects the radiation budget of the Earth system, modifies ocean bioproductivity and influences human health. Dust aerosol is a complex mixture of minerals. Dust mineral composition has several potentially important impacts to environment and society. Iron and phosphorus embedded in mineral aerosol are essential for the primary marine productivity when dust deposits over the open ocean. Dust also acts as efficient agent for heterogeneous ice nucleation and this process is dependent on mineralogical structure of dust. Recent findings in medical geology indicate possible role of minerals to human health. In this study, a new 1-km global database was developed for several minerals (Illite, Kaolinite, Smectite, Calcite, Quartz, Feldspar, Hematite and Gypsum) embedded in clay and silt populations of arid soils. For the database generation, high-resolution data sets on soil textures, soil types and land cover was used. Tin addition to the selected minerals, phosphorus was also added whose geographical distribution was specified from compiled literature and data on soil types. The developed global database was used to specify sources of mineral fractions in the DREAM dust model and to simulate atmospheric paths of minerals and their potential impacts on marine biochemistry and tropospheric ice nucleation.

  1. Mineral dust aerosols promote the formation of toxic nitropolycyclic aromatic compounds

    PubMed Central

    Kameda, Takayuki; Azumi, Eri; Fukushima, Aki; Tang, Ning; Matsuki, Atsushi; Kamiya, Yuta; Toriba, Akira; Hayakawa, Kazuichi

    2016-01-01

    Atmospheric nitrated polycyclic aromatic hydrocarbons (NPAHs), which have been shown to have adverse health effects such as carcinogenicity, are formed in part through nitration reactions of their parent polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. However, little is known about heterogeneous nitration rates of PAHs by gaseous NO2 on natural mineral substrates, such as desert dust aerosols. Herein by employing kinetic experiments using a flow reactor and surface analysis by Fourier transform infrared spectroscopy with pyridine adsorption, we demonstrate that the reaction is accelerated on acidic surfaces of mineral dust, particularly on those of clay minerals. In support of this finding, we show that levels of ambient particle-associated NPAHs in Beijing, China, significantly increased during heavy dust storms. These results suggest that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere and that they enhance the toxicity of mineral dust aerosols in urban environments. PMID:27075250

  2. NMMB/BSC-DUST: an online mineral dust atmospheric model from meso to global scales

    NASA Astrophysics Data System (ADS)

    Haustein, K.; Pérez, C.; Jorba, O.; Baldasano, J. M.; Janjic, Z.; Black, T.; Nickovic, S.

    2009-04-01

    While mineral dust distribution and effects are important at global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales. Most global dust models use prescribed wind fields provided by meteorological centers (e.g., NCEP and ECMWF) and their spatial resolution is currently never better than about 1°×1°. Regional dust models offer substantially higher resolution (10-20 km) and are typically coupled with weather forecast models that simulate processes that GCMs either cannot resolve or can resolve only poorly. These include internal circulation features such as the low-level nocturnal jet which is a crucial feature for dust emission in several dust ‘hot spot' sources in North Africa. Based on our modeling experience with the BSC-DREAM regional forecast model (http://www.bsc.es/projects/earthscience/DREAM/) we are currently implementing an improved mineral dust model [Pérez et al., 2008] coupled online with the new global/regional NMMB atmospheric model under development in NOAA/NCEP/EMC [Janjic, 2005]. The NMMB is an evolution of the operational WRF-NMME extending from meso to global scales. The NMMB will become the next-generation NCEP model for operational weather forecast in 2010. The corresponding unified non-hydrostatic dynamical core ranges from meso to global scale allowing regional and global simulations. It has got an add-on non-hydrostatic module and it is based on the Arakawa B-grid and hybrid pressure-sigma vertical coordinates. NMMB is fully embedded into the Earth System Modeling Framework (ESMF), treating dynamics and physics separately and coupling them easily within the ESMF structure. Our main goal is to provide global dust forecasts up to 7 days at mesoscale resolutions. New features of the model include a physically-based dust emission scheme after White [1979], Iversen and White [1982] and Marticorena and Bergametti [1995] that takes the effects of saltation and sandblasting into account

  3. Effect of ultraviolet on the survival of bacteria airborne in simulated Martian dust clouds.

    PubMed

    Hagen, C A; Hawrylewicz, E J; Anderson, B T; Cephus, M L

    1970-01-01

    A chamber was constructed to create simulated Martian dust storms and thereby study the survival of airborne micro-organisms while exposed to the rigors of the Martian environment, including ultraviolet irradiation. Representative types of sporeforming and non-sporeforming bacteria present in spacecraft assembly areas and indigenous to humans were studied. It was found that daily ultraviolet irradiation of 2 to 9 X 10(7) erg cm-2 was not sufficient to sterilize the dust clouds. The soil particles protected the organisms from ultraviolet irradiation since the numbers of survivors from irradiated environments were similar to those from unirradiated environments. Pending further data of the Martian environment, the contamination and dissemination of Mars with terrestrial micro-organisms is still a distinct possibility.

  4. Airborne Fungal and Bacterial Components in PM1 Dust from Biofuel Plants

    PubMed Central

    Madsen, Anne Mette; Schlünssen, Vivi; Olsen, Tina; Sigsgaard, Torben; Avci, Hediye

    2009-01-01

    Fungi grown in pure cultures produce DNA- or RNA-containing particles smaller than spore size (<1.5 μm). High exposures to fungi and bacteria are observed at biofuel plants. Airborne cultivable bacteria are often described to be present in clusters or associated with larger particles with an aerodynamic diameter (dae) of 2–8 μm. In this study, we investigate whether airborne fungal components smaller than spore size are present in bioaerosols in working areas at biofuel plants. Furthermore, we measure the exposure to bacteria and fungal components in airborne particulate matter (PM) with a D50 of 1 μm (called PM1 dust). PM1 was sampled using Triplex cyclones at a working area at 14 Danish biofuel plants. Millipore cassettes were used to sample ‘total dust’. The PM1 particles (29 samples) were analysed for content of 11 different components and the total dust was analysed for cultivable fungi, N-acetyl-β-D-glucosaminidase (NAGase), and (1 → 3)-β-D-glucans. In the 29 PM1 samples, cultivable fungi were found in six samples and with a median concentration below detection level. Using microscopy, fungal spores were identified in 22 samples. The components NAGase and (1 → 3)-β-D-glucans, which are mainly associated with fungi, were present in all PM1 samples. Thermophilic actinomycetes were present in 23 of the 29 PM1 samples [average = 739 colony-forming units (CFU) m−3]. Cultivable and ‘total bacteria’ were found in average concentrations of, respectively, 249 CFU m−3 and 1.8 × 105 m−3. DNA- and RNA-containing particles of different lengths were counted by microscopy and revealed a high concentration of particles with a length of 0.5–1.5 μm and only few particles >1.5 μm. The number of cultivable fungi and β-glucan in the total dust correlated significantly with the number of DNA/RNA-containing particles with lengths of between 1.0 and 1.5 μm, with DNA/RNA-containing particles >1.5 μm, and with other fungal components in PM1

  5. Carbon dioxide sequestration in cement kiln dust through mineral carbonation

    SciTech Connect

    Deborah N. Huntzinger; John S. Gierke; S. Komar Kawatra; Timothy C. Eisele; Lawrence L. Sutter

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO{sub 2} emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation. The degree of mineral carbonation achievable in cement kiln dust (CKD) under ambient temperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO{sub 2} with Ca(OH){sub 2}, and CaCO{sub 3} was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion. 35 refs., 3 figs., 1 tab.

  6. Carbon dioxide sequestration in cement kiln dust through mineral carbonation.

    PubMed

    Huntzinger, Deborah N; Gierke, John S; Kawatra, S Komar; Eisele, Timothy C; Sutter, Lawrence L

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO2 emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation The degree of mineral carbonation achievable in cement kiln dust (CKD) underambienttemperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO2 with Ca(OH)2, and CaCO3 was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion.

  7. Carbon dioxide sequestration in cement kiln dust through mineral carbonation.

    PubMed

    Huntzinger, Deborah N; Gierke, John S; Kawatra, S Komar; Eisele, Timothy C; Sutter, Lawrence L

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO2 emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation The degree of mineral carbonation achievable in cement kiln dust (CKD) underambienttemperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO2 with Ca(OH)2, and CaCO3 was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion. PMID:19368202

  8. Remote sensing for non-renewable resources - Satellite and airborne multiband scanners for mineral exploration

    NASA Technical Reports Server (NTRS)

    Goetz, Alexander F. H.

    1986-01-01

    The application of remote sensing techniques to mineral exploration involves the use of both spatial (morphological) as well as spectral information. This paper is directed toward a discussion of the uses of spectral image information and emphasizes the newest airborne and spaceborne sensor developments involving imaging spectrometers.

  9. Machine vision based particle size and size distribution determination of airborne dust particles of wood and bark pellets

    SciTech Connect

    Igathinathane, C; Pordesimo, L.O.

    2009-08-01

    Dust management strategies in industrial environment, especially of airborne dust, require quantification and measurement of size and size distribution of the particles. Advanced specialized instruments that measure airborne particle size and size distribution apply indirect methods that involve light scattering, acoustic spectroscopy, and laser diffraction. In this research, we propose a simple and direct method of airborne dust particle dimensional measurement and size distribution analysis using machine vision. The method involves development of a user-coded ImageJ plugin that measures particle length and width and analyzes size distribution of particles based on particle length from high-resolution scan images. Test materials were airborne dust from soft pine wood sawdust pellets and ground pine tree bark pellets. Subsamples prepared by dividing the actual dust using 230 mesh (63 m) sieve were analyzed as well. A flatbed document scanner acquired the digital images of the dust particles. Proper sampling, layout of dust particles in singulated arrangement, good contrast smooth background, high resolution images, and accurate algorithm are essential for reliable analysis. A halo effect around grey-scale images ensured correct threshold limits. The measurement algorithm used Feret s diameter for particle length and pixel-march technique for particle width. Particle size distribution was analyzed in a sieveless manner after grouping particles according to their distinct lengths, and several significant dimensions and parameters of particle size distribution were evaluated. Results of the measurement and analysis were presented in textual and graphical formats. The developed plugin was evaluated to have a dimension measurement accuracy in excess of 98.9% and a computer speed of analysis of <8 s/image. Arithmetic mean length of actual wood and bark pellets airborne dust particles were 0.1138 0.0123 and 0.1181 0.0149 mm, respectively. The airborne dust particles of

  10. The global distribution of mineral dust and its impacts on the climate system: A review

    NASA Astrophysics Data System (ADS)

    Choobari, O. Alizadeh; Zawar-Reza, P.; Sturman, A.

    2014-03-01

    Mineral dust aerosols, the tiny soil particles suspended in the atmosphere, have a key role in the atmospheric radiation budget and hydrological cycle through their radiative and cloud condensation nucleus effects. Current understanding of spatial and temporal variations of mineral dust, as well as its impacts on the climate system and cloud properties is outlined. Mineral dust aerosols are blown into the atmosphere mainly from arid and semi-arid regions where annual rainfall is extremely low and substantial amounts of alluvial sediment have been accumulated over long periods. They are subject to long-range transport of an intercontinental scale, including North African dust plumes over the Atlantic Ocean, summer dust plumes from the Arabian Peninsula over the Arabian Sea and Indian Ocean and spring dust plumes from East Asia over the Pacific Ocean. Mineral dust aerosols influence the climate system and cloud microphysics in multiple ways. They disturb the climate system directly by scattering and partly absorbing shortwave and longwave radiation, semi-directly by changing the atmospheric cloud cover through evaporation of cloud droplets (i.e. the cloud burning effect), and indirectly by acting as cloud and ice condensation nuclei, which changes the optical properties of clouds (i.e. the first indirect effect), and may decrease or increase precipitation formation (i.e. the second indirect effect). Radiative forcing by mineral dust is associated with changes in atmospheric dynamics that may change the vertical profile of temperature and wind speed, through which a feedback effect on dust emission can be established.

  11. Dielectrophoretic separation of airborne microbes and dust particles using a microfluidic channel for real-time bioaerosol monitoring.

    PubMed

    Moon, Hui-Sung; Nam, Yun-Woo; Park, Jae Chan; Jung, Hyo-Il

    2009-08-01

    Airborne microbes such as fungi, bacteria, and viruses are a threat to public health. Robust and real-time detection systems are necessary to prevent and control such dangerous biological particles in public places and dwellings. For direct and real-time detection of airborne microbes, samples must be collected and typically resuspended in liquid prior to detection; however, environmental particles such as dust are also trapped in such samples. Therefore, the isolation of target bacteria or a selective collection of microbes from unwanted nonbiological particles prior to detection is of great importance. Dielectrophoresis (DEP), the translational motion of charge neutral matter in nonuniform electric fields, is an emerging technique that can rapidly separate biological particles in microfluidics because low voltages produce significant and contactless forces on particles without any modification or labeling. In this paper, we propose a new method for the separation of airborne microbes using DEP with a simple and novel curved electrode design for separating bacteria in a solution containing beads or dust that are taken from an airborne environmental sample. Using this method, we successfully isolated 90% of the airborne bacterium Micrococcus luteus from a mixture of bacteria and dust using a microfluidic device, consisting of novel curved electrodes that attract bacteria and repel or leave dust particles. As there has been little research on analyzing environmental samples using microfluidics and DEP, this work describes a novel strategy for a rapid and direct bioaerosol monitoring system.

  12. Real-time PCR detection of toxigenic Fusarium in airborne and settled grain dust and associations with trichothecene mycotoxins.

    PubMed

    Halstensen, Anne Straumfors; Nordby, Karl-Christian; Eduard, Wijnand; Klemsdal, Sonja Sletner

    2006-12-01

    Inhalation of immunomodulating mycotoxins produced by Fusarium spp. that are commonly found in grain dust may imply health risks for grain farmers. Airborne Fusarium and mycotoxin exposure levels are mainly unknown due to difficulties in identifying Fusarium and mycotoxins in personal aerosol samples. We used a novel real-time PCR method to quantify the fungal trichodiene synthase gene (tri5) and DNA specific to F. langsethiae and F. avenaceum in airborne and settled grain dust, determined the personal inhalant exposure level to toxigenic Fusarium during various activities, and evaluated whether quantitative measurements of Fusarium-DNA could predict trichothecene levels in grain dust. Airborne Fusarium-DNA was detected in personal samples even from short tasks (10-60 min). The median Fusarium-DNA level was significantly higher in settled than in airborne grain dust (p < 0.001), and only the F. langsethiae-DNA levels correlated significantly in settled and airborne dust (r(s) = 0.20, p = 0.003). Both F. langsethiae-DNA and tri5-DNA were associated with HT-2 and T-2 toxins (r(s) = 0.24-0.71, p < 0.05 to p < 00.01) in settled dust, and could thus be suitable as indicators for HT-2 and T-2. The median personal inhalant exposure to specific toxigenic Fusarium spp. was less than 1 genome m(-3), but the exposure ranged from 0-10(5) genomes m(-3). This study is the first to apply real-time PCR on personal samples of inhalable grain dust for the quantification of tri5 and species-specific Fusarium-DNA, which may have potential for risk assessments of inhaled trichothecenes. PMID:17133280

  13. Effects of studded tires on roadside airborne dust pollution in Niigata, Japan

    NASA Astrophysics Data System (ADS)

    Fukuzaki, Norio; Yanaka, Takaaki; Urushiyama, Yoshio

    Two series of dust samples, collected by Andersen impactors (denoted by AN) and low-volume air samplers (denoted by LV), were investigated with respect to roadside airborne dusts collected in two different periods in 1983. These were the periods (i) with studded tires (February and March) and (ii) without studded tires (October). Multi-element determinations of these samples were made by neutron activation analysis and atomic absorption spectrometry. The total concentration of AN in roadside air for period (i) was about three times higher than for the period without studded tires. The lithophilic elements such as Na, Al, K, Ca, Ti, Fe and Th, and component-metal elements of stud tip, W and Ta, produced a significant increase in atmospheric concentration in winter. The contribution of pavement material, one of the most interesting components of airborne particles in this study, was related to total AN and LV by the chemical element balance method. It made up only 16 percent (9.1 μgm -3) of AN in October, compared with 46 percent (70.2 μgm -3) in February. It was also observed that the atmospheric concentrations of pavement debris to total LV decreased with the distance from the road to each sampling site.

  14. Airborne Sunphotometry of African Dust and Marine Boundary Layer Aerosols in PRIDE

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Redemann, Jens; Russell, Philip; Schmid, Beat; Reid, Jeff; Pilewskie, Peter; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    The Puerto Rico Dust Experiment (PRIDE) was conducted during summer 2000 to study the radiative, microphysical and transport properties of Saharan dust in the Caribbean region. During PRIDE, NASA Ames Research Center's six-channel airborne autotracking sunphotometer (AATS-6) was operated aboard a Piper Navajo airplane based at Roosevelt Roads Naval Station on the northeast coast of Puerto Rico. AATS-6 measurements were taken during 21 science flights off the coast of Puerto Rico in the western Caribbean. Data were acquired within and above the Marine Boundary Layer (MBL) and the Saharan Aerosol Layer (SAL) up to 5.5 km altitude tinder a wide range of dust loadings. Aerosol optical depth (AOD) spectra and columnar water vapor (CWV) values have been calculated from the AATS-6 measurements by using sunphotometer calibration data obtained at Mauna Loa Observatory (3A kin ASL) before (May) and after (October) PRIDE. Mid-visible AOD values measured near the surface during PRIDE ranged from 0.07 on the cleanest day to 0.55 on the most turbid day. Values measured above the MBL were as high as 0.35; values above the SAL were as low as 0.01. The fraction of total column AOD due to Saharan dust cannot be determined precisely from AATS-6 AOD data alone due to the uncertainty in the extent of vertical mixing of the dust down through the MBL. However, analyses of ground-based and airborne in-situ aerosol sampling measurements and ground-based aerosol lidar backscatter data should yield accurate characterization of the vertical mixing that will enable calculation of the Saharan dust AOD component from the sunphotometer data. Examples will be presented showing measured AATS-6 AOD spectra, calculated aerosol extinction and water vapor density vertical profiles, and aerosol size distributions retrieved by inversion of the AOD spectra. Near sea-surface AOD spectra acquired by AATS-6 during horizontal flight legs at 30 m ASL are available for validation of AOD derived from coincident

  15. Exposure to airborne microorganisms, dust and endotoxin during processing of valerian roots on farms.

    PubMed

    Skórska, Czesława; Sitkowska, Jolanta; Krysińska-Traczyk, Ewa; Cholewa, Grazyna; Dutkiewicz, Jacek

    2005-01-01

    The aim of this study was to determine the levels of microorganisms, dust and endotoxin in the air during various stages of valerian (Valeriana officinalis) roots processing by herb farmers and to examine the species composition of airborne microflora. Air samples were collected on glass fibre filters by use of personal samplers on 15 farms owned by valerian cultivating farmers, located in Lublin province (eastern Poland). The concentrations of total viable microorganisms (bacteria + fungi) in the air showed a marked variability and were within a range of 0.95-7,966.6 x 10(3) cfu/m (3). Though median was relatively low (10.75 x 10(3) cfu/m (3)), on 4 farms the concentrations exceeded the level of 10(5) cfu/m (3) and on 1 farm the level of 10(6) cfu/m (3). During the processing of valerian roots, distinct changes could be observed in the composition of airborne microflora. In the first stages of processing, the freshly dug and washed roots until shaking in the drying room, the most numerous were Gram-negative bacteria of the family Pseudomonadaceae (mostly Stenotrophomonas maltophilia, Pseudomonas chlororaphis and Pseudomonas fluorescens). After drying, the dominant organisms were thermo-resistant endospore-forming bacilli (Bacillus spp.) and fungi, among which prevailed Aspergillus fumigatus. Altogether, 29 species or genera of bacteria and 19 species or genera of fungi were identified in the farm air during valerian processing, of these, 10 and 12 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of airborne dust and endotoxin on the examined farms were very large and ranged from 10.0-776.7 mg/m (3), and from 0.15-24,448.2 microg/m (3), respectively (medians 198.3 mg/m (3) and 40.48 microg/m (3)). In conclusion, farmers cultivating valerian could be exposed during processing of valerian roots to large concentrations of airborne microorganisms, dust and endotoxin posing a risk of work

  16. Spatial distribution of mineral dust single scattering albedo based on DREAM model

    NASA Astrophysics Data System (ADS)

    Kuzmanoski, Maja; Ničković, Slobodan; Ilić, Luka

    2016-04-01

    Mineral dust comprises a significant part of global aerosol burden. There is a large uncertainty in estimating role of dust in Earth's climate system, partly due to poor characterization of its optical properties. Single scattering albedo is one of key optical properties determining radiative effects of dust particles. While it depends on dust particle sizes, it is also strongly influenced by dust mineral composition, particularly the content of light-absorbing iron oxides and the mixing state (external or internal). However, an assumption of uniform dust composition is typically used in models. To better represent single scattering albedo in dust atmospheric models, required to increase accuracy of dust radiative effect estimates, it is necessary to include information on particle mineral content. In this study, we present the spatial distribution of dust single scattering albedo based on the Dust Regional Atmospheric Model (DREAM) with incorporated particle mineral composition. The domain of the model covers Northern Africa, Middle East and the European continent, with horizontal resolution set to 1/5°. It uses eight particle size bins within the 0.1-10 μm radius range. Focusing on dust episode of June 2010, we analyze dust single scattering albedo spatial distribution over the model domain, based on particle sizes and mineral composition from model output; we discuss changes in this optical property after long-range transport. Furthermore, we examine how the AERONET-derived aerosol properties respond to dust mineralogy. Finally we use AERONET data to evaluate model-based single scattering albedo. Acknowledgement We would like to thank the AERONET network and the principal investigators, as well as their staff, for establishing and maintaining the AERONET sites used in this work.

  17. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Determination of dust concentration....

  18. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  19. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  20. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Determination of dust concentration. 33.32... MINES Test Requirements § 33.32 Determination of dust concentration. (a) Concentrations of airborne dust... microscopic technique shall be employed in determining concentrations of dust in terms of millions...

  1. Comparison of the mixing state of long-range transported Asian and African mineral dust

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Elizabeth; Ault, Andrew P.; Zauscher, Melanie D.; Mayol-Bracero, Olga L.; Prather, Kimberly A.

    2015-08-01

    Mineral dust from arid regions represents the second largest global source of aerosols to the atmosphere. Dust strongly impacts the radiative balance of the earth's atmosphere by directly scattering solar radiation and acting as nuclei for the formation of liquid droplets and ice nuclei within clouds. The climate effects of mineral dust aerosols are poorly understood, however, due to their complex chemical and physical properties, which continuously evolve during atmospheric transport. This work focuses on characterizing atmospheric mineral dust from the two largest global dust sources: the Sahara Desert in Africa and the Gobi and Taklamakan Deserts in Asia. Measurements of individual aerosol particle size and chemical mixing state were made at El Yunque National Forest, Puerto Rico, downwind of the Sahara Desert, and Gosan, South Korea, downwind of the Gobi and Taklamakan Deserts. In general, the chemical characterization of the individual dust particles detected at these two sites reflected the dominant mineralogy of the source regions; aluminosilicate-rich dust was more common at El Yunque (∼91% of El Yunque dust particles vs. ∼69% of Gosan dust particles) and calcium-rich dust was more common at Gosan (∼22% of Gosan dust particles vs. ∼2% of El Yunque dust particles). Furthermore, dust particles from Africa and Asia were subjected to different transport conditions and atmospheric processing; African dust showed evidence of cloud processing, while Asian dust was modified via heterogeneous chemistry and direct condensation of secondary species. A larger fraction of dust detected at El Yunque contained the cloud-processing marker oxalate ion compared to dust detected at Gosan (∼20% vs ∼9%). Additionally, nearly 100% of dust detected at Gosan contained nitrate, showing it was aged via heterogeneous reactions with nitric acid, compared to only ∼60% of African dust. Information on the distinct differences in the chemical composition of mineral dust

  2. Stimulation of alveolar macrophages by mineral dusts in vitro: luminol-dependent chemiluminescence study

    SciTech Connect

    Vilim, V.; Wilhelm, J.; Brzak, P.; Hurych, J.

    1987-02-01

    Luminol-dependent chemiluminescence (CL) of normal (nonactivated) rabbit alveolar macrophages (AMs) was measured in suspension upon stimulation by various size fractions of one quartz dust sample or by various mineral dusts (quartz, corundum, anatas, and chrysotile asbestos as an example of fibrous dust). The CL-triggering capacity of the tested dusts was inhibited by their preincubation with autologous serum. The intensity of luminol-dependent CL induced by particulate dusts upon their action on AMs depended on the kind of dust, on the dust particle sizes, and on the ratio of the number of particles to the number of cells in a given suspension. The cytotoxicity and/or fibrogenicity of the dust and its capacity to trigger the luminol-dependent CL of nonadherent AMs were not directly correlated.

  3. Quantitative interpretation of airborne gravity gradiometry data for mineral exploration

    NASA Astrophysics Data System (ADS)

    Martinez, Cericia D.

    In the past two decades, commercialization of previously classified instrumentation has provided the ability to rapidly collect quality gravity gradient measurements for resource exploration. In the near future, next-generation instrumentation are expected to further advance acquisition of higher-quality data not subject to pre-processing regulations. Conversely, the ability to process and interpret gravity gradiometry data has not kept pace with innovations occurring in data acquisition systems. The purpose of the research presented in this thesis is to contribute to the understanding, development, and application of processing and interpretation techniques available for airborne gravity gradiometry in resource exploration. In particular, this research focuses on the utility of 3D inversion of gravity gradiometry for interpretation purposes. Towards this goal, I investigate the requisite components for an integrated interpretation workflow. In addition to practical 3D inversions, components of the workflow include estimation of density for terrain correction, processing of multi-component data using equivalent source for denoising, quantification of noise level, and component conversion. The objective is to produce high quality density distributions for subsequent geological interpretation. I then investigate the use of the inverted density model in orebody imaging, lithology differentiation, and resource evaluation. The systematic and sequential approach highlighted in the thesis addresses some of the challenges facing the use of gravity gradiometry as an exploration tool, while elucidating a procedure for incorporating gravity gradient interpretations into the lifecycle of not only resource exploration, but also resource modeling.

  4. Mineral dust photochemistry induces nucleation events in the presence of SO2.

    PubMed

    Dupart, Yoan; King, Stephanie M; Nekat, Bettina; Nowak, Andreas; Wiedensohler, Alfred; Herrmann, Hartmut; David, Gregory; Thomas, Benjamin; Miffre, Alain; Rairoux, Patrick; D'Anna, Barbara; George, Christian

    2012-12-18

    Large quantities of mineral dust particles are frequently ejected into the atmosphere through the action of wind. The surface of dust particles acts as a sink for many gases, such as sulfur dioxide. It is well known that under most conditions, sulfur dioxide reacts on dust particle surfaces, leading to the production of sulfate ions. In this report, for specific atmospheric conditions, we provide evidence for an alternate pathway in which a series of reactions under solar UV light produces first gaseous sulfuric acid as an intermediate product before surface-bound sulfate. Metal oxides present in mineral dust act as atmospheric photocatalysts promoting the formation of gaseous OH radicals, which initiate the conversion of SO(2) to H(2)SO(4) in the vicinity of dust particles. Under low dust conditions, this process may lead to nucleation events in the atmosphere. The laboratory findings are supported by recent field observations near Beijing, China, and Lyon, France.

  5. Building an industry-wide occupational exposure database for respirable mineral dust - experiences from the IMA dust monitoring programme

    NASA Astrophysics Data System (ADS)

    Houba, Remko; Vlaanderen, Jelle; Jongen, Richard; Kromhout, Hans

    2009-02-01

    Building an industry-wide database with exposure measurements of respirable mineral dust is a challenging operation. The Industrial Minerals Association (IMA-Europe) took the initiative to create an exposure database filled with data from a prospective and ongoing dust monitoring programme that was launched in 2000. More than 20 industrial mineral companies have been collecting exposure data following a common protocol since then. Recently in 2007 ArboUnie and IRAS evaluated the quality of the collected exposure data for data collected up to winter 2005/2006. The data evaluated was collected in 11 sampling campaigns by 24 companies at 84 different worksites and considered about 8,500 respirable dust measurements and 7,500 respirable crystalline silica. In the quality assurance exercise four criteria were used to evaluate the existing measurement data: personal exposure measurements, unique worker identity, sampling duration not longer than one shift and availability of a limit of detection. Review of existing exposure data in the IMA dust monitoring programme database showed that 58% of collected respirable dust measurements and 62% of collected respirable quartz could be regarded as 'good quality data' meeting the four criteria mentioned above. Only one third of the measurement data included repeated measurements (within a sampling campaign) that would allow advanced statistical analysis incorporating estimates of within- and between-worker variability in exposure to respirable mineral dust. This data came from 7 companies comprising measurements from 23 sites. Problematic data was collected in some specific countries and to a large extent this was due to local practices and legislation (e.g. allowing 40-h time weighted averages). It was concluded that the potential of this unique industry-wide exposure database is very high, but that considerable improvements can be made. At the end of 2006 relatively small but essential changes were made in the dust monitoring

  6. Mineral dust and major ion concentrations in snowpit samples from the NEEM site, Greenland

    NASA Astrophysics Data System (ADS)

    Kang, Jung-Ho; Hwang, Heejin; Hong, Sang Bum; Hur, Soon Do; Choi, Sung-Deuk; Lee, Jeonghoon; Hong, Sungmin

    2015-11-01

    Polar ice sheets conserve atmospheric aerosols at the time of snowfall, which can be used to reconstruct past climate and environmental conditions. We investigated mineral dust and major ion records in snowpit samples obtained from the northwestern Greenland ice sheet near the North Greenland Eemian Ice Drilling (NEEM) camp in June 2009. We analyzed the samples for mineral dust concentrations as well as stable water isotopes (δ18O, δD, and deuterium excess) and major ions (Cl-, SO42-, methanesulfonic acid (MSA), Na+, and Ca2+). Seasonal δ18O and δD cycles indicate that the snowpit samples covered a six-year period from spring 2003 to early summer 2009. Concentrations of mineral dust, nss-Ca2+, and nss-SO42- showed seasonal deposition events with maxima in the winter-spring layers. On the other hand, the Cl-/Na+ ratio and the concentrations of MSA exhibited maxima in the summer layers, making them useful indicators for the summer season. Moreover, an anomalous atmospheric mineral dust event was recorded at a depth of 165-170 cm corresponding to late winter 2005 to spring 2006. A back trajectory analysis suggests that a major contributor to the Greenland aerosol was an air mass passing over the Canadian Arctic and North America. Several trajectories point to Asian regions as a dust source. The mineral dust deposited at NEEM was strongly influenced by long-range atmospheric transport and dust input from arid source areas in northern China and Mongolia.

  7. Size distribution and optical properties of African mineral dust after intercontinental transport

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Formenti, Paola; Desboeufs, Karine; Chevaillier, Servanne; Triquet, Sylvain; Maillé, Michel; Cazaunau, Mathieu; Laurent, Benoit; Mayol-Bracero, Olga L.; Vallejo, Pamela; Quiñones, Mariana; Gutierrez-Molina, Ian E.; Cassola, Federico; Prati, Paolo; Andrews, Elisabeth; Ogren, John

    2016-06-01

    The transatlantic transport of mineral dust from Africa is a persistent atmospheric phenomenon, clue for understanding the impacts of dust at the global scale. As part of the DUST Aging and Transport from Africa to the Caribbean (Dust-ATTACk) intensive field campaign, the size distribution and optical properties of mineral dust were measured in June-July 2012 on the east coast of Puerto Rico, more than 5000 km from the west coast of Africa. During the recorded dust events, the PM10 (particulate matter 10 micrometers or less in diameter) concentrations increased from 20 to 70 µg m-3. Remote sensing observations and modeling analysis were used to identify the main source regions, which were found in the Western Sahara, Mauritania, Algeria, Niger, and Mali. The microphysical and optical properties of the dust plumes were almost independent of origin. The size distribution of mineral dust after long-range transport may have modal diameters similar to those on the eastern side of the Atlantic short time after emission, possibly depending on height of transport. Additional submicron particles of anthropogenic absorbing aerosols (likely from regional marine traffic activities) can be mixed within the dust plumes, without affecting in a significant way the PM10 absorption properties of dust observed in Puerto Rico. The Dust-ATTACk experimental data set may be useful for modeling the direct radiative effect of dust. For accurate representation of dust optical properties over the Atlantic remote marine region, we recommend mass extinction efficiency (MEE) and single-scattering albedo values in the range 1.1-1.5 m2 g-1 and 0.97-0.98, respectively, for visible wavelengths.

  8. How the Assumed Size Distribution of Dust Minerals Affects the Predicted Ice Forming Nuclei

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Fridlind, A. M.; Pérez García-Pando, C.; Miller, R. L.; Knopf, D. A.

    2015-12-01

    The formation of ice in clouds depends on the availability of ice forming nuclei (IFN). Dust aerosol particles are considered the most important source of IFN at a global scale. Recent laboratory studies have demonstrated that the mineral feldspar provides the most efficient dust IFN for immersion freezing and together with kaolinite for deposition ice nucleation, and that the phyllosilicates illite and montmorillonite (a member of the smectite group) are of secondary importance.A few studies have applied global models that simulate mineral specific dust to predict the number and geographical distribution of IFN. These studies have been based on the simple assumption that the mineral composition of soil as provided in data sets from the literature translates directly into the mineral composition of the dust aerosols. However, these tables are based on measurements of wet-sieved soil where dust aggregates are destroyed to a large degree. In consequence, the size distribution of dust is shifted to smaller sizes, and phyllosilicates like illite, kaolinite, and smectite are only found in the size range <2 μm. In contrast, in measurements of the mineral composition of dust aerosols, the largest mass fraction of these phyllosilicates is found in the size range >2 μm as part of dust aggregates. Conversely, the mass fraction of feldspar is smaller in this size range, varying with the geographical location. This may have a significant effect on the predicted IFN number and its geographical distribution.An improved mineral specific dust aerosol module has been recently implemented in the NASA GISS Earth System ModelE2. The dust module takes into consideration the disaggregated state of wet-sieved soil, on which the tables of soil mineral fractions are based. To simulate the atmospheric cycle of the minerals, the mass size distribution of each mineral in aggregates that are emitted from undispersed parent soil is reconstructed. In the current study, we test the null

  9. How the Assumed Size Distribution of Dust Minerals Affects the Predicted Ice Forming Nuclei

    NASA Technical Reports Server (NTRS)

    Perlwitz, Jan P.; Fridlind, Ann M.; Garcia-Pando, Carlos Perez; Miller, Ron L.; Knopf, Daniel A.

    2015-01-01

    The formation of ice in clouds depends on the availability of ice forming nuclei (IFN). Dust aerosol particles are considered the most important source of IFN at a global scale. Recent laboratory studies have demonstrated that the mineral feldspar provides the most efficient dust IFN for immersion freezing and together with kaolinite for deposition ice nucleation, and that the phyllosilicates illite and montmorillonite (a member of the smectite group) are of secondary importance.A few studies have applied global models that simulate mineral specific dust to predict the number and geographical distribution of IFN. These studies have been based on the simple assumption that the mineral composition of soil as provided in data sets from the literature translates directly into the mineral composition of the dust aerosols. However, these tables are based on measurements of wet-sieved soil where dust aggregates are destroyed to a large degree. In consequence, the size distribution of dust is shifted to smaller sizes, and phyllosilicates like illite, kaolinite, and smectite are only found in the size range 2 m. In contrast, in measurements of the mineral composition of dust aerosols, the largest mass fraction of these phyllosilicates is found in the size range 2 m as part of dust aggregates. Conversely, the mass fraction of feldspar is smaller in this size range, varying with the geographical location. This may have a significant effect on the predicted IFN number and its geographical distribution.An improved mineral specific dust aerosol module has been recently implemented in the NASA GISS Earth System ModelE2. The dust module takes into consideration the disaggregated state of wet-sieved soil, on which the tables of soil mineral fractions are based. To simulate the atmospheric cycle of the minerals, the mass size distribution of each mineral in aggregates that are emitted from undispersed parent soil is reconstructed. In the current study, we test the null

  10. Does the long-range transport of African mineral dust across the Atlantic enhance their hygroscopicity?

    NASA Astrophysics Data System (ADS)

    Denjean, Cyrielle; Caquineau, Sandrine; Desboeufs, Karine; Laurent, Benoit; Quiñones Rosado, Mariana; Vallejo, Pamela; Mayol-Bracero, Olga; Formenti, Paola

    2015-04-01

    Influence of mineral dust on radiation balance is largely dependent on their ability to interact with water. While fresh mineral dusts are highly hydrophobic, various transformation processes (coagulation, heterogeneous chemical reaction) can modify the dust physical and chemical properties during long-range transport, which, in turn, can change the dust hygroscopic properties. The model predictions of the radiative effect by mineral dust still suffer of the lack of certainty of dust hygroscopic properties, and their temporal evolution during long-range transport. We present the first direct surface measurements of the hygroscopicity of Saharan dust after long-range transport over the Atlantic Ocean, their relationship with chemical composition, their influence on particle size and shape and implications for optical properties. Particles were collected during the DUST Aging and TransporT from Africa to the Caribbean (Dust-AttaCk) campaign at the Cape San Juan Puerto Rico station in June-July 2012. Environmental scanning electron microscopy (ESEM) was used to analyze the size, shape, chemical composition and hygroscopic properties of individual particles. At different levels of concentrations in summertime, the coarse mode of atmospheric aerosols in Puerto Rico is dominated by Saharan mineral dust. Most of aged dust particles survived atmospheric transport intact with no observed internal mixture with other species and did not show hygroscopic growth up to 94% relative humidity. This is certainly due to the fact that in summertime dust is mostly transported above the marine boundary layer. A minor portion of mineral dust (approximately 19-28% by number) were involved in atmospheric heterogeneous reactions with acidic gases (likely SO2 and HCl) and sea salt aggregation. While sulfate- and chloride-coated dust remained extremely hydrophobic, dust particles in internal mixing with NaCl underwent profound changes in their hygroscopicity, therefore in size and shape. We

  11. The adsorption of fungal ice-nucleating proteins on mineral dusts: a terrestrial reservoir of atmospheric ice-nucleating particles

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Daniel; Murray, Benjamin J.; Ross, James; Webb, Michael E.

    2016-04-01

    The occurrence of ice-nucleating particles (INPs) in our atmosphere has a profound impact on the properties and lifetime of supercooled clouds. However, the identities, sources and abundances of airborne particles capable of efficiently nucleating ice at relatively low supercoolings (T > -15 °C) remain enigmatic. Recently, several studies have suggested that unidentified biogenic residues in soil dusts are likely to be an important source of these efficient atmospheric INPs. While it has been shown that cell-free proteins produced by common soil-borne fungi are exceptional INPs, whether these fungi are a source of ice-nucleating biogenic residues in soils has yet to be shown. In particular, it is unclear whether upon adsorption to soil mineral particles, the activity of fungal ice-nucleating proteins is retained or is reduced, as observed for other soil enzymes. Here we show that proteins from a common soil fungus (Fusarium avenaceum) do in fact preferentially bind to and impart their ice-nucleating properties to the common clay mineral kaolinite. The ice-nucleating activity of the proteinaceous INPs is found to be unaffected by adsorption to the clay, and once bound the proteins do not readily desorb, retaining much of their activity even after multiple washings with pure water. The atmospheric implications of the finding that nanoscale fungal INPs can effectively determine the nucleating abilities of lofted soil dusts are discussed.

  12. Alignment of atmospheric mineral dust due to electric field

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Bailey, J.; Lucas, P. W.; Hough, J. H.; Hirst, E.

    2007-12-01

    Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction indicating the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here. It is also possible that the alignment and the electric field modify dust transport.

  13. 75 FR 64411 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ... Verification) (65 FR 42122, July 7, 2000, and 68 FR 10784, March 6, 2003); (3) ``Determination of Concentration of Respirable Coal Mine Dust'' (Single Sample) (65 FR 42068, July 7, 2000, and 68 FR 10940 March 6, 2003); and (4) ``Respirable Coal Mine Dust: Continuous Personal Dust Monitor (CPDM)'' (74 FR...

  14. An automatic collector to monitor insoluble atmospheric deposition: application for mineral dust deposition

    NASA Astrophysics Data System (ADS)

    Laurent, B.; Losno, R.; Chevaillier, S.; Vincent, J.; Roullet, P.; Bon Nguyen, E.; Ouboulmane, N.; Triquet, S.; Fornier, M.; Raimbault, P.; Bergametti, G.

    2015-07-01

    Deposition is one of the key terms of the mineral dust cycle. However, dust deposition remains poorly constrained in transport models simulating the atmospheric dust cycle. This is mainly due to the limited number of relevant deposition measurements. This paper aims to present an automatic collector (CARAGA), specially developed to sample the total (dry and wet) atmospheric deposition of insoluble dust in remote areas. The autonomy of the CARAGA can range from 25 days to almost 1 year depending on the programmed sampling frequency (from 1 day to 2 weeks respectively). This collector is used to sample atmospheric deposition of Saharan dust on the Frioul islands in the Gulf of Lions in the Western Mediterranean. To quantify the mineral dust mass in deposition samples, a weighing and ignition protocol is applied. Almost 2 years of continuous deposition measurements performed on a weekly sampling basis on Frioul Island are presented and discussed with air mass trajectories and satellite observations of dust. Insoluble mineral deposition measured on Frioul Island was 2.45 g m-2 for February to December 2011 and 3.16 g m-2 for January to October 2012. Nine major mineral deposition events, measured during periods with significant MODIS aerosol optical depths, were associated with air masses coming from the southern Mediterranean Basin and North Africa.

  15. Mineral dust indirect effects and cloud radiative feedbacks of a simulated idealized nocturnal squall line

    NASA Astrophysics Data System (ADS)

    Seigel, R. B.; van den Heever, S. C.; Saleeby, S. M.

    2013-04-01

    Mineral dust is arguably the most abundant aerosol species in the world and as such potentially plays a large role in aerosol indirect effects (AIEs). This study assesses and isolates the individual responses in a squall line that arise (1) from radiation, (2) from dust altering the microphysics, as well as (3) from the synergistic effects between (1) and (2). To accomplish these tasks, we use the Regional Atmospheric Modeling System (RAMS) set up as a cloud-resolving model (CRM). The CRM contains aerosol and microphysical schemes that allow mineral dust particles to nucleate as cloud drops and ice crystals, replenish upon evaporation and sublimation, be tracked throughout hydrometeor transition, and be scavenged by precipitation and dry sedimentation. Factor separation is used on four simulations of the squall line in order to isolate the individual roles of radiation (RADIATION), microphysically active dust (DUST MICRO), and the nonlinear interactions of those factors (SYNERGY). Results indicate that RADIATION acts to increase precipitation, intensify the cold pool, and enhance the mesoscale organization of the squall line due to changes in microphysics originating from cloud top cooling. Conversely, DUST MICRO decreases precipitation, weakens the cold pool, and weakens the mesoscale organization of the squall line due to an enhancement of the warm rain process. SYNERGY shows little impact on the squall line, except near the freezing level, where an increase in mesoscale organization takes place. The combined effect of the mineral dust AIE due to both DUST MICRO and SYNERGY is to weaken the squall line.

  16. The derivation of estimated dust exposures for U. S. coal miners working before 1970

    SciTech Connect

    Attfield, M.D.; Morring, K. )

    1992-04-01

    A number of reports on the prevalence of coal workers' pneumoconiosis in U.S. coal miners have been published, yet very little is known about the relationship between dust exposure and pneumoconiosis levels in the U.S. This report describes the derivation of cumulative dust exposure estimates by back-extrapolation of data processed by the Mine Safety and Health Administration after 1970 by using a ratio of dust concentrations based on information collected during environmental surveys at certain U.S. mines by the Bureau of Mines between 1968 and 1969. Cumulative personal dust exposure estimates were calculated by using occupational histories obtained from the miners and job-specific estimates of dust concentration. In other reports, the resulting estimated exposures have been shown to correlate well with various measures of respiratory morbidity.

  17. Potential exposures to airborne and settled surface dust in residential areas of lower Manhattan following the collapse of the World Trade Center--New York City, November 4-December 11, 2001.

    PubMed

    2003-02-21

    Following the terrorist attacks of September 11, 2001, which destroyed the World Trade Center (WTC) in lower Manhattan, the New York City (NYC) Department of Health and Mental Hygiene (DOHMH) and the Agency for Toxic Substances and Disease Registry (ATSDR), with assistance from the U.S. Public Health Service (PHS) Commissioned Corps Readiness Force and the WTC Environmental Assessment Working Group, assessed the composition of outdoor and indoor settled surface and airborne dust in residential areas around the WTC and in comparison areas. This report summarizes the results of the investigation, which found 1) similar levels of airborne total fibers in lower and in upper Manhattan, 2) greater percentage levels of synthetic vitreous fibers (SVF) and mineral components of concrete and building wallboard in settled dust of residential areas in lower Manhattan than in upper Manhattan, and 3) low levels of asbestos in some settled surface dust in lower Manhattan residential areas. Based in part on the results of this investigation, the U.S. Environmental Protection Agency (EPA) is cleaning and sampling residential areas as requested by lower Manhattan residents. In addition, to assess any short- or long-term health effects of smoke, dust, and airborne substances around the WTC site, DOHMH and ATSDR are developing a registry that will track the health of persons who were most highly exposed to these materials.

  18. Dynamic Dust Accumulation and Dust Removal Observed on the Mars Exploration Rover Magnets

    NASA Technical Reports Server (NTRS)

    Bertelsen, P.; Bell, J. F., III; Goetz, W.; Gunnlaugsson, H. P.; Herkenhoff, K. E.; Hviid, S. F.; Johnson, J. R.; Kinch, K. M.; Knudsen, J. M.; Madsen, M. B.

    2005-01-01

    The Mars Exploration Rovers each carry a set of Magnetic Properties Experiments designed to investigate the properties of the airborne dust in the Martian atmosphere. It is a preferred interpretation of previous experiments that the airborne dust in the Martian atmosphere is primarily composed by composite silicate particles containing one or more highly magnetic minerals as a minor constituent. The ultimate goal of the magnetic properties experiments on the Mars Exploration Rover mission is to provide some information/ constraints on whether the dust is formed by volcanic, meteoritic, aqueous, or other processes. The first problem is to identify the magnetic mineral(s) in the airborne dust on Mars. While the overall results of the magnetic properties experiments are presented in, this abstract will focus on dust deposition and dust removal on some of the magnets.

  19. Mineral dust radiative effect on snow in European Alps

    NASA Astrophysics Data System (ADS)

    Di Mauro, Biagio; Fava, Francesco; Ferrero, Luca; Garzonio, Roberto; Baccolo, Giovanni; Delmonte, Barbara; Colombo, Roberto

    2015-04-01

    Mineral Dust (MD) is known to increase the absorption of solar radiation when deposited on snow and ice. This process causes a decrease in the albedo and may enhance snow melting, resulting in a positive radiative forcing (RF) in climate system. The RF from MD on snow can assume high values (~100-200 W/m2) after depositional events altering snow and ice radiative balance and hydrological cycle. In this study, we analyzed a significant MD transport happened during spring in 2014 and in particular its impact on snow optical properties. The dust plume was entrained in the troposphere over the Saharan desert (North African Grand Erg Oriental) during the passage of a cold front, and then transported NE over the Mediterranean by cyclonic atmospheric conditions. MD reached the European Alps where it was deposited by snowfall. We conducted a field proximal sensing survey in 10 plots (2x2 meters) at the Artavaggio plains (Lecco, Italy) with a hyperspectral radiometer (ASD Field-spec pro) collecting reflected radiance of snow in a spectral range between 350 and 2500 nm. Surface snow samples were collected and analyzed in clean room with microparticle counter in order to determine the size distribution and the concentration of MD in each sample. In addition, total mass of insoluble material was also measured by filtering the melted snow. Observed spectra were compared to those simulated by parameterizing the Snow, Ice, and Aerosol Radiation (SNICAR) radiative transfer model with observed variables such as snow grain size, snow density and size distribution of MD. We defined a novel spectral index, the Snow Darkening Index (SDI) to combine red and green wavelengths showing nonlinear correlation with measured MD concentration. Instantaneous radiative forcing was then estimated as the spectral difference between upwelling irradiance of plot containing MD and pure snow plots. MD concentration was up to 107 ppm and total mass of insoluble material up to 325 ppm. Measured RF values

  20. Airborne Dust Cloud Measurements at the INL National Security Test Range

    SciTech Connect

    Michael L. Abbott; Norm Stanley; Larry Radke; Charles Smeltzer

    2007-09-01

    On July 11, 2007, a surface, high-explosive test (<20,000 lb TNT-equivalent) was carried out at the National Security Test Range (NSTR) on the Idaho National Laboratory (INL) Site. Aircraft-mounted rapid response (1-sec) particulate monitors were used to measure airborne PM-10 concentrations directly in the dust cloud and to develop a PM-10 emission factor that could be used for subsequent tests at the NSTR. The blast produced a mushroom-like dust cloud that rose approximately 2,500–3,000 ft above ground level, which quickly dissipated (within 5 miles of the source). In general, the cloud was smaller and less persistence than expected, or that might occur in other areas, likely due to the coarse sand and subsurface conditions that characterize the immediate NSTR area. Maximum short time-averaged (1-sec) PM-10 concentrations at the center of the cloud immediately after the event reached 421 µg m-3 but were rapidly reduced (by atmospheric dispersion and fallout) to near background levels (~10 µg m-3) after about 15 minutes. This occurred well within the INL Site boundary, about 8 km (5 miles) from the NSTR source. These findings demonstrate that maximum concentrations in ambient air beyond the INL Site boundary (closest is 11.2 km from NSTR) from these types of tests would be well within the 150 µg m-3 24-hour National Ambient Air Quality Standards for PM-10. Aircraft measurements and geostatistical techniques were used to successfully quantify the initial volume (1.64E+9 m3 or 1.64 km3) and mass (250 kg) of the PM-10 dust cloud, and a PM-10 emission factor (20 kg m-3 crater soil volume) was developed for this specific type of event at NSTR. The 250 kg of PM-10 mass estimated from this experiment is almost seven-times higher than the 36 kg estimated for the environmental assessment (DOE-ID 2007) using available Environmental Protection Agency (EPA 1995) emission factors. This experiment demonstrated that advanced aircraft-mounted instruments operated by

  1. Separating Dust Mixtures and Other External Aerosol Mixtures Using Airborne High Spectral Resolution Lidar Data

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Vaughan, M.; Hostetler, C. A.; Rogers, R. R.; Hair, J. W.; Cook, A. L.; Harper, D. B.

    2013-12-01

    Knowledge of aerosol type is important for source attribution and for determining the magnitude and assessing the consequences of aerosol radiative forcing. The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) has acquired considerable datasets of both aerosol extensive parameters (e.g. aerosol optical depth) and intensive parameters (e.g. aerosol depolarization ratio, lidar ratio) that can be used to infer aerosol type. An aerosol classification methodology has been used extensively to classify HSRL-1 aerosol measurements of different aerosol types including dust, smoke, urban pollution, and marine aerosol. However, atmospheric aerosol is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the aerosol. Here we present a comprehensive and unified set of rules for characterizing external mixtures using several key aerosol intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. Our mixing rules apply not just to the scalar values of aerosol intensive parameters, but to multi-dimensional normal distributions with variance in each measurement dimension. We illustrate the applicability of the mixing rules using examples of HSRL-1 data where mixing occurred between different aerosol types, including advected Saharan dust mixed with the marine boundary layer in the Caribbean Sea and locally generated dust mixed with urban pollution in the Mexico City surroundings. For each of these cases we infer a time-height cross section of mixing ratio along the flight track and we partition aerosol extinction into portions attributed to the two pure types. Since multiple aerosol intensive parameters are measured and included in these calculations, the techniques can also be used for cases without significant depolarization (unlike similar work by earlier researchers), and so a third example of a

  2. Hf-Nd-Sr isotopic fingerprinting of mineral dust from Asian and North African deserts

    NASA Astrophysics Data System (ADS)

    Ji, J.; Zhao, W.; Balsam, W.

    2015-12-01

    Mineral dust accounts for more than 50% of the atmospheric dust loading and plays an important role in the marine and terrestrial geochemical cycles. The deserts in North Africa, Northern China and Southern Mongolia are the major sources of mineral dust and have been studied intensively over past decades, especially with Sr, Nd and recently Hf isotopes which are seen as powerful tools to identify source areas. However, the isotopic compositions of dust are highly dependent on particle size hindering the ability to accurately identify dust provenance. The clay fraction (<2 μm) comprises about half of all mineral dust and has unique minerals phases dominanted by clay minerals. Once the clay-sized particles are deflated to the upper troposphere, they are transported over long distances and are removed from the atmosphere mainly by wet deposition. Thus, the clay-sized isotopic fingerprints from deserts may be ideal targets not only for tracking the provenance tracing of long-distance transported mineral dust, but also to provide an unparalleled window for understanding the global dust cycle, especially eolian dust preserved in deep-sea sediments and ice cores. In this work we investigate multivariate joint radiogenic Sr, Nd, and Hf isotopic compositions obtained from complete dissolution of clay-sized fractions of surface sediments from Asian and North African deserts. Asian dust source samples included the ten Northern China deserts and sandy lands - the Taklimakan, Gurbantunggut, Qaidam, Badaim Jaran, Tengger and Mu Us deserts, and the Hobq, Hulun Buirm, Onqin Daga and Horqin sandy land - and Mongolian Gobi desert. North African dust samples were from four transects in the Sahara and Sahel from Mali, Togo, Egypt and Morocco . Our results on the clay-sized isotopic measurements of these samples describe (1) the general characteristics of dusts from the Asian with ɛNd from -17.3 to 0.98, ɛHf from -5.95 to 3.68 and 87Sr/86Sr from 0.710113 to 0.73306, and North

  3. Modeling of atmospheric iron processing carried by mineral dust and its deposition to ocean

    NASA Astrophysics Data System (ADS)

    Nickovic, Slobodan; Vukovic, Ana; Vujadinovic, Mirjam

    2014-05-01

    Relatively insoluble iron in dust originating from desert soils increases its solubility after Fe carried by mineral dust is chemically processed by the atmosphere. After dust is deposited deposition to the ocean, soluble Fe as a nutrient could enhance the marine primary production. The atmospheric dust cycle is driven by the atmospheric processes often of smaller, meso-scales. The soil mineralogy of dust emitted from sources determines also how much Fe in the aerosol will be finding. Once Fe is exposed to the atmospheric processes, the atmospheric radiation, clouds and polluted air will chemically affect the iron in dust. Global dust-iron models, having typical horizontal resolutions of 100-300 km which are mostly used to numerically simulate the fate of iron in the atmosphere can provide rather global picture of the dust and iron transport, but not details. Such models often introduce simplistic approximation on the Fe content in dust-productive soils. To simulate the Fe processing we instead implemented a high resolution regional atmospheric dust-iron model with detailed 1km global map for the geographic distribution of Fe content in soil. We also introduced a parameterization of the Fe processing caused by dust mineralogy, cloud processes and solar radiation. We will present results from simulation experiments in order to explore the model capability to reproduce major observed patterns of deposited Fe into the Atlantic cruises.

  4. The importance of feldspar for ice nucleation by mineral dust in mixed-phase clouds.

    PubMed

    Atkinson, James D; Murray, Benjamin J; Woodhouse, Matthew T; Whale, Thomas F; Baustian, Kelly J; Carslaw, Kenneth S; Dobbie, Steven; O'Sullivan, Daniel; Malkin, Tamsin L

    2013-06-20

    The amount of ice present in mixed-phase clouds, which contain both supercooled liquid water droplets and ice particles, affects cloud extent, lifetime, particle size and radiative properties. The freezing of cloud droplets can be catalysed by the presence of aerosol particles known as ice nuclei. One of the most important ice nuclei is thought to be mineral dust aerosol from arid regions. It is generally assumed that clay minerals, which contribute approximately two-thirds of the dust mass, dominate ice nucleation by mineral dust, and many experimental studies have therefore focused on these materials. Here we use an established droplet-freezing technique to show that feldspar minerals dominate ice nucleation by mineral dusts under mixed-phase cloud conditions, despite feldspar being a minor component of dust emitted from arid regions. We also find that clay minerals are relatively unimportant ice nuclei. Our results from a global aerosol model study suggest that feldspar ice nuclei are globally distributed and that feldspar particles may account for a large proportion of the ice nuclei in Earth's atmosphere that contribute to freezing at temperatures below about -15 °C.

  5. Integrated approach towards understanding interactions of mineral dust aerosol with warm clouds

    NASA Astrophysics Data System (ADS)

    Kumar, Prashant

    2011-12-01

    Mineral dust is ubiquitous in the atmosphere and represents a dominant type of particulate matter by mass. Dust particles can serve as cloud condensation nuclei (CCN), giant CCN (GCCN), or ice nuclei (IN), thereby, affecting cloud microphysics, albedo, and lifetime. Despite its well-recognized importance, assessments of dust impacts on clouds and climate remain highly uncertain. This thesis addresses the role of dust as CCN and GCCN with the goal of improving our understanding of dust-warm cloud interactions and their representation in climate models. Most studies to date focus on the soluble fraction of aerosol particles when describing cloud droplet nucleation, and overlook the interactions of the hydrophilic insoluble fraction with water vapor. A new approach to include such interactions (expressed by the process of water vapor adsorption) is explored, by combining multilayer Frenkel-Halsey-Hill (FHH) physical adsorption isotherm and curvature (Kelvin) effects. The importance of adsorption activation theory (FHH-AT) is corroborated by measurements of CCN activity of mineral aerosols generated from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. A new aerosol generation setup for CCN measurements was developed based on a dry generation technique capable of reproducing natural dust aerosol emission. Based on the dependence of critical supersaturation with particle dry diameter, it is found that the FHH-AT is a better framework for describing fresh (and unprocessed) dust CCN activity than the classical Kohler theory (KT). Ion Chromatography (IC) measurements performed on fresh regional dust samples indicate negligible soluble fraction, and support that water vapor adsorption is the prime source of CCN activity in the dust. CCN measurements with the commonly used wet generated mineral aerosol (from atomization of a dust aqueous suspension) are also carried out. Results indicate that the method is subject

  6. Alignment of atmospheric mineral dust due to electric field

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Bailey, J.; Lucas, P. W.; Hough, J. H.; Hirst, E.

    2007-09-01

    Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction consistent with the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling also indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here.

  7. The impact of glacier retreat from the Ross Sea on local climate: Characterization of mineral dust in the Taylor Dome ice core, East Antarctica

    NASA Astrophysics Data System (ADS)

    Aarons, S. M.; Aciego, S. M.; Gabrielli, P.; Delmonte, B.; Koornneef, J. M.; Wegner, A.; Blakowski, M. A.

    2016-06-01

    Recent declines in ice shelf and sea ice extent experienced in polar regions highlight the importance of evaluating variations in local weather patterns in response to climate change. Airborne mineral particles (dust) transported through the atmosphere and deposited on ice sheets and glaciers in Antarctica and Greenland can provide a robust set of tools for resolving the evolution of climatic systems through time. Here we present the first high time resolution radiogenic isotope (strontium and neodymium) data for Holocene dust in a coastal East Antarctic ice core, accompanied by rare earth element composition, dust concentration, and particle size distribution during the last deglaciation. We aim to use these combined ice core data to determine dust provenance, with variations indicative of shifts in either dust production, sources, and/or transport pathways. We analyzed a series of 17 samples from the Taylor Dome (77°47‧47″S, 158°43‧26″E) ice core, 113-391 m in depth from 1.1-31.4 ka. Radiogenic isotopic and rare earth element compositions of dust during the last glacial period are in good agreement with previously measured East Antarctic ice core dust records. In contrast, the Holocene dust dataset displays a broad range in isotopic and rare earth element compositions, suggesting a shift from long-range transported dust to a more variable, local input that may be linked to the retreat of the Ross Ice Shelf during the last deglaciation. Observed changes in the dust cycle inferred from a coastal East Antarctic ice core can thus be used to infer an evolving local climate.

  8. Radiative Effect of Saharan Mineral Dust on the Nonlinear Dynamics of African Easterly Waves

    NASA Astrophysics Data System (ADS)

    Grogan, D.; Nathan, T. R.; Chen, S. H.

    2014-12-01

    The radiative effects of Saharan mineral dust aerosols on the nonlinear dynamics of African easterly waves (AEWs) are examined using the Weather Research and Forecasting Dust (WRFD) model. The WRFD model is governed by the Advanced Research WRF dynamical core, and continuity equations for twelve dust particle sizes that represent the spectrum of mineral dust aerosols observed in the atmosphere. To incorporate dust radiative effects in the model, aerosol optical properties (i.e. optical depth, single scattering albedo, and asymmetric parameters) for all dust sizes are inputted into the shortwave and longwave radiation schemes. By choosing zonal-mean distributions of zonal wind and temperature that are consistent with summer over Northwest Africa, idealized dry simulations explore the nonlinear behavior of AEWs in the presence of dust. The initial zonal-mean dust fields are represented as simple distributions that vary in structure and concentration, which are consistent with observed dust events over Africa. Specific AEW features investigated in the simulations include the evolution of wave energy, Eliassen-Palm fluxes, and spatial structures. Among the questions to be addressed are the following: How does the concentration and spatial distribution of the dust field affect the strength and timing of AEW amplitude saturation? What impact will the dust induced wave fluxes have on the horizontal or vertical shear of the zonal-mean AEJ? Does the interaction between the AEJ, AEW and dust affect the timing and location of the AEW trough, and thus the formation of critical latitudes? Answers to these questions will aid in the understanding and forecasting of AEWs, and their possible subsequent development into tropical storms.

  9. New mineral dust record from the TALDICE ice core (East Antarctica)

    NASA Astrophysics Data System (ADS)

    Maggi, V.; Delmonte, B.; Albani, S.; Mazzola, C.

    2010-12-01

    Aeolian mineral dust is an active component of the climate system, interacting both directly and indirectly with radiation and biogeochemistry. Its deposition and stratigraphical preservation in appropriate environmental setting leaves deposits that once dated can be used as paleoclimate proxies. In particular dust records from ice cores can provide insights into past variations of environmental conditions at the dust source areas, atmospheric circulation, the hydrological cycle at source and deposition sites and dust deposition mechanisms. Here we present the new dust record from the 1620 m deep TALDICE ice core, drilled at Talos Dome (159°11' E, 72°49' S, 2315 m A.S.L.), on the edge of the East Antarctic plateau, about 290 km from the Southern Ocean and 250 km from the Ross Sea. We analysed variations in dust concentration, depositional flux, size distributions and geochemical fingerprint. The TALDICE dust records confirms the major findings from previous ice core studies in terms of the big glacial/interglacial variations in dust deposition, thanks to the relatively high accumulation rate and good dating. We also show new peculiar aspects emerging for this record, such as the importance of Antarctic sources for dust for this peripheral sites and the relation between variations in dust deposition during the deglaciation and the Holocene to variations in the atmospheric circulation in the Ross Sea.

  10. Laboratory investigations of mineral dust near-backscattering depolarization ratios

    NASA Astrophysics Data System (ADS)

    Järvinen, E.; Kemppinen, O.; Nousiainen, T.; Kociok, T.; Möhler, O.; Leisner, T.; Schnaiter, M.

    2016-07-01

    Recently, there has been increasing interest to derive the fractions of fine- and coarse-mode dust particles from polarization lidar measurements. For this, assumptions of the backscattering properties of the complex dust particles have to be made either by using empirical data or particle models. Laboratory measurements of dust backscattering properties are important to validate the assumptions made in the lidar retrievals and to estimate their uncertainties. Here, we present laboratory measurements of linear and circular near-backscattering (178°) depolarization ratios of over 200 dust samples measured at 488 and 552 nm wavelengths. The measured linear depolarization ratios ranged from 0.03 to 0.36 and were strongly dependent on the particle size. The strongest size-dependence was observed for fine-mode particles as their depolarization ratios increased almost linearly with particle median diameter from 0.03 to 0.3, whereas the coarse-mode particle depolarization values stayed rather constant with a mean linear depolarization ratio of 0.27. The depolarization ratios were found to be insensitive to the dust source region or thin coating of the particles or to changes in relative humidity. We compared the measurements with results of three different scattering models. With certain assumptions for model particle shape, all the models were capable of correctly describing the size-dependence of the measured dust particle, albeit the model particles significantly differed in composition, shape and degree of complexity. Our results show potential for distinguishing the dust fine- and coarse-mode distributions based on their depolarization properties and, thus, can serve the lidar community as an empirical reference.

  11. Airborne bacteria transported with Sahara dust particles from Northern Africa to the European Alps

    NASA Astrophysics Data System (ADS)

    Lazzaro, A.; Meola, M.

    2015-12-01

    The Sahara Desert is the most important source of aerosols transported across the Mediterranean towards Europe. Airborne microorganisms associated with aerosols may be transported over long distances and act as colonizers of distant habitats. However, little is known on the composition and viability of such microorganisms, due to difficulties related to their detection, collection and isolation. Here we describe an in-depth assessment of the bacterial communities associated with Sahara dust (SD) particles deposited on snow. Two distinct SD events reaching the European Alps in February and May 2014 were preserved as distinct ochre-coloured layers within the snowpack. In June 2014, we collected samples from a snow profile at 3621 m a.s.l. close to the Jungfraujoch (Swiss Alps). SD particles were analyzed by Scanning Electron Microscopy and Energy-Dispersive X-Ray Spectroscopy (SEM-EDX). Backward trajectories were calculated using the NOAA HYSPLIT model. Bacterial communities were charac-terized by MiSeq Illumina sequencing of the 16S rRNA gene. Microbial physiological profiles were assessed by incubation of samples on BIOLOG plates. The SD-layers were generally enriched in illite and kaolinite particles as compared to the adjacent snow layers. The source of SD could be traced back to Algeria. We observed distinct bacterial community structures in the SD-layers as compared to the clean snow layers. While sporulating bacteria were not enriched in the SD-layers, low abundant (<1%) phyla such as Gemmatimonadetes and Deinococcus-Thermus appeared to be specific bioindicators for SD. Both phyla are adapted to arid oligotrophic environments and UV radiation and thus are well suited to survive the harsh conditions of long-distance airborne transport. Our results show that bacteria are viable and metabolically active after the trek to the European Alps.

  12. Atmospheric processing outside clouds increases soluble iron in mineral dust.

    PubMed

    Shi, Zongbo; Krom, Michael D; Bonneville, Steeve; Benning, Liane G

    2015-02-01

    Iron (Fe) is a key micronutrient regulating primary productivity in many parts of the global ocean. Dust deposition is an important source of Fe to the surface ocean, but most of this Fe is biologically unavailable. Atmospheric processing and reworking of Fe in dust aerosol can increase the bioavailable Fe inputs to the ocean, yet the processes are not well understood. Here, we experimentally simulate and model the cycling of Fe-bearing dust between wet aerosol and cloud droplets. Our results show that insoluble Fe in dust particles readily dissolves under acidic conditions relevant to wet aerosols. By contrast, under the higher pH conditions generally relevant to clouds, Fe dissolution tends to stop, and dissolved Fe precipitates as poorly crystalline nanoparticles. If the dust-bearing cloud droplets evaporated again (returning to the wet aerosol stage with low pH), those neo-formed Fe nanoparticles quickly redissolve, while the refractory Fe-bearing phases continue to dissolve gradually. Overall, the duration of the acidic, wet aerosol stage ultimately increases the amount of potentially bioavailable Fe delivered to oceans, while conditions in clouds favor the formation of Fe-rich nanoparticles in the atmosphere.

  13. 76 FR 2617 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Mine...' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors AGENCY: Mine Safety and.... SUMMARY: The Mine Safety and Health Administration (MSHA) is extending the comment period on the...

  14. 75 FR 73995 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ..., 2010, MSHA announced that it would hold six public hearings on the proposed rule (75 FR 69617). Due to... the proposed rule on October 19, 2010 (75 FR 64412); it is available on MSHA's Web site at http://www...' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors AGENCY: Mine Safety...

  15. Comparison of Air Impaction and Electrostatic Dust Collector Sampling Methods to Assess Airborne Fungal Contamination in Public Buildings.

    PubMed

    Normand, Anne-Cécile; Ranque, Stéphane; Cassagne, Carole; Gaudart, Jean; Sallah, Kankoé; Charpin, Denis-André; Piarroux, Renaud

    2016-03-01

    Many ailments can be linked to exposure to indoor airborne fungus. However, obtaining a precise measurement of airborne fungal levels is complicated partly due to indoor air fluctuations and non-standardized techniques. Electrostatic dust collector (EDC) sampling devices have been used to measure a wide range of airborne analytes, including endotoxins, allergens, β-glucans, and microbial DNA in various indoor environments. In contrast, viable mold contamination has only been assessed in highly contaminated environments such as farms and archive buildings. This study aimed to assess the use of EDCs, compared with repeated air-impactor measurements, to assess airborne viable fungal flora in moderately contaminated indoor environments. Indoor airborne fungal flora was cultured from EDCs and daily air-impaction samples collected in an office building and a daycare center. The quantitative fungal measurements obtained using a single EDC significantly correlated with the cumulative measurement of nine daily air impactions. Both methods enabled the assessment of fungal exposure, although a few differences were observed between the detected fungal species and the relative quantity of each species. EDCs were also used over a 32-month period to monitor indoor airborne fungal flora in a hospital office building, which enabled us to assess the impact of outdoor events (e.g. ground excavations) on the fungal flora levels on the indoor environment. In conclusion, EDC-based measurements provided a relatively accurate profile of the viable airborne flora present during a sampling period. In particular, EDCs provided a more representative assessment of fungal levels compared with single air-impactor sampling. The EDC technique is also simpler than performing repetitive air-impaction measures over the course of several consecutive days. EDC is a versatile tool for collecting airborne samples and was efficient for measuring mold levels in indoor environments.

  16. Statistical analysis of the size and elemental composition of airborne coal-mine dust. Open File Report (Interim) 1984-86

    SciTech Connect

    Mutmansky, J.M.; Lee, C.

    1987-03-01

    The report was part of an ongoing effort at The Pennsylvania State University to investigate the characteristics of airborne mine dusts and its relationship to coal worker's pneumoconiosis (CWP). The specific purpose of the project was to analyze the size and elemental composition of airborne coal mine dusts and the ramifications of these characteristics. A dust sampling strategy using multi-stage cascade impactors was established for characterization purposes. Analysis of the size distributions of the collected samples was performed based upon the aerodynamic diameter of the dust. Patterns of lognormality and bimodality were found in the data. Elemental analysis was performed by the PIXE method for both major and trace elements. Size dependency and locational variation of the elemental composition of the airborne dust were significant in some cases. Relationships to the mining section activities were also investigated.

  17. The influence of coal physical and mechanical properties and mining energy consumption factor on airborne respirable dust level

    SciTech Connect

    Koziel, A.; Malec, M.; Wardas, E.

    1999-07-01

    The fact that there are not any explicitly defined relationships describing the influence of physical and mechanical properties of coal and of energy consumption factor on dust level prompted Polish and American investigators to carry out a joint research project within the framework of the US-Poland Maria Sklodowska-Curie Joint Fund II. The paper presents methods used to perform tests under laboratory conditions at the Pittsburgh Research Laboratory as well as under real conditions in the course of coal cutting in Polish coal mines. Measuring systems and results of the tests are described. The analysis carried out has provided a basis for determining the influence of specified operational parameters, i.e., coal compression strength R{sub c}, coal cuttability factor A, energy consumption factor of mining E{sub uc}, load of cutting drums as well as of laboratory parameters, i.e., grindability, coal breakage characteristics (product size distribution), moisture content, volatile and fixed carbon content, specific energy of crushing on a level of generated dust (total dust, specific dust and airborne respirable dust). The effect of technical parameters, i.e., face height, airflow velocity in a face, amount and pressure of water in spraying systems of longwall shearers, depth of cut taken by a cutting drum and application of powered cowls on dust level under operating conditions are also presented. Results of the tests made it possible to work out guidelines relating to methods and technology for effective reduction of dust emission on longwall faces.

  18. Factors Affecting Vegetable Growers’ Exposure to Fungal Bioaerosols and Airborne Dust

    PubMed Central

    Hansen, Vinni M.; Meyling, Nicolai Vitt; Winding, Anne; Eilenberg, Jørgen; Madsen, Anne Mette

    2012-01-01

    We have quantified vegetable growers’ exposure to fungal bioaerosol components including (1→3)-β-d-glucan (β-glucan), total fungal spores, and culturable fungal units. Furthermore, we have evaluated factors that might affect vegetable growers’ exposure to fungal bioaerosols and airborne dust. Investigated environments included greenhouses producing cucumbers and tomatoes, open fields producing cabbage, broccoli, and celery, and packing facilities. Measurements were performed at different times during the growth season and during execution of different work tasks. Bioaerosols were collected with personal and stationary filter samplers. Selected fungal species (Beauveria spp., Trichoderma spp., Penicillium olsonii, and Penicillium brevicompactum) were identified using different polymerase chain reaction-based methods and sequencing. We found that the factors (i) work task, (ii) crop, including growth stage of handled plant material, and (iii) open field versus greenhouse significantly affected the workers’ exposure to bioaerosols. Packing of vegetables and working in open fields caused significantly lower exposure to bioaerosols, e.g. mesophilic fungi and dust, than harvesting in greenhouses and clearing of senescent greenhouse plants. Also removing strings in cucumber greenhouses caused a lower exposure to bioaerosols than harvest of cucumbers while removal of old plants caused the highest exposure. In general, the exposure was higher in greenhouses than in open fields. The exposures to β-glucan during harvest and clearing of senescent greenhouse plants were very high (median values ranging between 50 and 1500 ng m−3) compared to exposures reported from other occupational environments. In conclusion, vegetable growers’ exposure to bioaerosols was related to the environment, in which they worked, the investigated work tasks, and the vegetable crop. PMID:22003240

  19. Airborne dust and aeroallergen concentration in a horse stable under two different management systems.

    PubMed

    Woods, P S; Robinson, N E; Swanson, M C; Reed, C E; Broadstone, R V; Derksen, F J

    1993-05-01

    Airborne dust concentration (ADC) was measured in 2 different horse management systems using an Andersen cascade impactor in the box-stall, and a personal Marple cascade impactor attached to the halter to measure ADC in the breathing zone. The levels of aeroallergens implicated in chronic obstructive pulmonary disease were measured by radioallergosorbent-inhibition immunoassay. A conventional management system (System C) utilising hay feed and straw bedding, and a recommended environment (System R) utilising wood shaving bedding and a complete pelleted diet were studied. In the stall, total and respirable ADC (geometric mean) were significantly higher in System C (2.55 mg/m3; 0.44 mg/m3, respectively) than in System R (0.70 mg/m3; 0.20 mg/m3, respectively). In System C, the total and respirable ADC in the breathing zone (17.51 mg/m3; 9.28 mg/m3) were much higher than in the stall, but values in both regions were similar in System R (0.52 mg/m3; 0.30 mg/m3). Major aeroallergens were significantly higher in System C than in System R: Micropolyspora faeni (1423 ng/m3 and 705 ng/m3), Aspergillus fumigatus (1823 ng/m3 and 748 ng/m3), and mite allergens (1420 ng/m3 and 761 ng/m3). Measurement of ADC with personal samplers indicates that the very high inhalation challenge in the breathing zone is not reflected in measurements of stall air quality. When compared with System C, System R produced only 3% of the respirable dust burden in the breathing zone and a decreased aeroallergen challenge.

  20. Predicting the Mineral and Chemical Composition of Dust Aerosols: Evaluation and Implications

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Pérez García-Pando, C.; Miller, R. L.

    2014-12-01

    Soil dust aerosols in Earth system models are typically assumed to have globally uniform properties. However, important climate processes related to dust depend on the aerosol mineral and chemical composition, which varies regionally. Such processes include aerosol radiative forcing, transport of bioavailable iron that catalyzes marine photosynthesis, heterogeneous chemistry, ice nucleation, and cloud condensation.We have implemented a new version of the soil dust aerosol scheme in the NASA GISS Earth System ModelE that takes into account the mineral composition of the dust particles. Dust aerosols are represented as an external mixture of minerals such as illite, kaolinite, smectite, carbonates, quartz, feldspar and gypsum, as well as iron oxides and accretions of iron oxides with each of the these minerals.We present a new publically available compilation of measurements of mineral fractions derived from ca. 50 references from the literature. This compilation is used to evaluate our new model of mineral and elemental composition within ModelE. We discuss the challenges of comparing simulated mineral fractions to measurements, which often come from field campaigns and ship cruises of limited duration. Despite uncertainties of the measurements, we show the importance of estimating the undisturbed size distribution of the parent soil prior to wet sieving, along with the modification of this size distribution during emission. In particular, our new model reproduces measurements showing greater amount of aerosols at silt sizes (whose diameters exceed 2 μm) including significant amounts of clay mineral aerosols (like illite) at silt sizes. Our model also reduces the systematic overestimation of quartz, while allowing iron to be transported farther from its source as impurities than in its pure, crystalline form.

  1. Modeling the global emission, transport and deposition of trace elements associated with mineral dust

    DOE PAGES

    Zhang, Y.; Mahowald, N.; Scanza, R.; Journet, E.; Desboeufs, K.; Albani, S.; Kok, J.; Zhuang, G.; Chen, Y.; Cohen, D. D.; et al

    2014-12-17

    Trace element deposition from desert dust has important impacts on ocean primary productivity. In this study, emission inventories for 8 elements, which are primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si were determined based on a global mineral dataset and a soils dataset. Datasets of elemental fractions were used to drive the desert dust model in the Community Earth System Model (CESM) in order to simulate the elemental concentrations of atmospheric dust. Spatial variability of mineral dust elemental fractions was evident on a global scale, particularly for Ca. Simulations of global variations in the Camore » / Al ratio, which typically ranged from around 0.1 to 5.0 in soil sources, were consistent with observations, suggesting this ratio to be a good signature for dust source regions. The simulated variable fractions of chemical elements are sufficiently different that estimates of deposition should include elemental variations, especially for Ca, Al and Fe. The model results have been evaluated with observational elemental aerosol concentration data from desert regions and dust events in non-dust regions, providing insights into uncertainties in the modeling approach. The ratios between modeled and observed elemental fractions ranged from 0.7 to 1.6 except for 3.4 and 3.5 for Mg and Mn, respectivly. Using the soil data base improved the correspondence of the spatial hetereogeneity in the modeling of several elements (Ca, Al and Fe) compared to observations. Total and soluble dust associated element fluxes into different ocean basins and ice sheets regions have been estimated, based on the model results. Annual inputs of soluble Mg, P, Ca, Mn, Fe and K associated with dust using mineral dataset were 0.28 Tg, 16.89 Gg, 1.32 Tg, 22.84 Gg, 0.068 Tg, and 0.15 Tg to global oceans and ice sheets.« less

  2. Modeling the global emission, transport and deposition of trace elements associated with mineral dust

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Mahowald, N.; Scanza, R.; Journet, E.; Desboeufs, K.; Albani, S.; Kok, J.; Zhuang, G.; Chen, Y.; Cohen, D. D.; Paytan, A.; Patey, M. D.; Achterberg, E. P.; Engelbrecht, J. P.; Fomba, K. W.

    2014-12-01

    Trace element deposition from desert dust has important impacts on ocean primary productivity. In this study, emission inventories for 8 elements, which are primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si were determined based on a global mineral dataset and a soils dataset. Datasets of elemental fractions were used to drive the desert dust model in the Community Earth System Model (CESM) in order to simulate the elemental concentrations of atmospheric dust. Spatial variability of mineral dust elemental fractions was evident on a global scale, particularly for Ca. Simulations of global variations in the Ca / Al ratio, which typically ranged from around 0.1 to 5.0 in soil sources, were consistent with observations, suggesting this ratio to be a good signature for dust source regions. The simulated variable fractions of chemical elements are sufficiently different that estimates of deposition should include elemental variations, especially for Ca, Al and Fe. The model results have been evaluated with observational elemental aerosol concentration data from desert regions and dust events in non-dust regions, providing insights into uncertainties in the modeling approach. The ratios between modeled and observed elemental fractions ranged from 0.7 to 1.6 except for 3.4 and 3.5 for Mg and Mn, respectivly. Using the soil data base improved the correspondence of the spatial hetereogeneity in the modeling of several elements (Ca, Al and Fe) compared to observations. Total and soluble dust associated element fluxes into different ocean basins and ice sheets regions have been estimated, based on the model results. Annual inputs of soluble Mg, P, Ca, Mn, Fe and K associated with dust using mineral dataset were 0.28 Tg, 16.89 Gg, 1.32 Tg, 22.84 Gg, 0.068 Tg, and 0.15 Tg to global oceans and ice sheets.

  3. Modeling of mineral dust in the atmosphere: Sources, transport, and optical thickness

    NASA Technical Reports Server (NTRS)

    Tegen, Ina; Fung, Inez

    1994-01-01

    A global three-dimensional model of the atmospheric mineral dust cycle is developed for the study of its impact on the radiative balance of the atmosphere. The model includes four size classes of minearl dust, whose source distributions are based on the distributions of vegetation, soil texture and soil moisture. Uplift and deposition are parameterized using analyzed winds and rainfall statistics that resolve high-frequency events. Dust transport in the atmosphere is simulated with the tracer transport model of the Goddard Institute for Space Studies. The simulated seasonal variations of dust concentrations show general reasonable agreement with the observed distributions, as do the size distributions at several observing sites. The discrepancies between the simulated and the observed dust concentrations point to regions of significant land surface modification. Monthly distribution of aerosol optical depths are calculated from the distribution of dust particle sizes. The maximum optical depth due to dust is 0.4-0.5 in the seasonal mean. The main uncertainties, about a factor of 3-5, in calculating optical thicknesses arise from the crude resolution of soil particle sizes, from insufficient constraint by the total dust loading in the atmosphere, and from our ignorance about adhesion, agglomeration, uplift, and size distributions of fine dust particles (less than 1 micrometer).

  4. Atmospheric transport and deposition of mineral dust to the ocean: implications for research needs.

    PubMed

    Schulz, Michael; Prospero, Joseph M; Baker, Alex R; Dentener, Frank; Ickes, Luisa; Liss, Peter S; Mahowald, Natalie M; Nickovic, Slobodan; García-Pando, Carlos Pérez; Rodríguez, Sergio; Sarin, Manmohan; Tegen, Ina; Duce, Robert A

    2012-10-01

    This paper reviews our knowledge of the measurement and modeling of mineral dust emissions to the atmosphere, its transport and deposition to the ocean, the release of iron from the dust into seawater, and the possible impact of that nutrient on marine biogeochemistry and climate. Of particular concern is our poor understanding of the mechanisms and quantities of dust deposition as well as the extent of iron solubilization from the dust once it enters the ocean. Model estimates of dust deposition in remote oceanic regions vary by more than a factor of 10. The fraction of the iron in dust that is available for use by marine phytoplankton is still highly uncertain. There is an urgent need for a long-term marine atmospheric surface measurement network, spread across all oceans. Because the southern ocean is characterized by large areas with high nitrate but low chlorophyll surface concentrations, that region is particularly sensitive to the input of dust and iron. Data from this region would be valuable, particularly at sites downwind from known dust source areas in South America, Australia, and South Africa. Coordinated field experiments involving both atmospheric and marine measurements are recommended to address the complex and interlinked processes and role of dust/Fe fertilization on marine biogeochemistry and climate.

  5. Selenium and exposure to fibrogenic mineral dust: a mini-review.

    PubMed

    Muzembo, Basilua Andre; Deguchi, Yoji; Ngatu, Nlandu Roger; Eitoku, Masamitsu; Hirota, Ryoji; Suganuma, Narufumi

    2015-04-01

    Individuals exposed to fibrogenic mineral dust may exhibit an impaired antioxidant system and produce high levels of reactive oxygen and nitrogen species through immune cells, contributing to the perturbation of immune cell function, inflammation, fibrosis and lung cancer. The lung diseases which are caused by inhalation of fibrogenic mineral dust, known as pneumoconioses, develop progressively and irreversibly over decades. At the moment there is no known cure. The trace element selenium has potent antioxidant and anti-inflammatory properties mediated mainly through selenoproteins. Research has demonstrated that selenium has the ability to protect against cardiovascular diseases; to kill cancer cells in vitro and reduce cancer incidence; and to immunomodulate various cellular signaling pathways. For these reasons, selenium has been proposed as a promising therapeutic agent in oxidative stress associated pathology that in theory would be beneficial for the prevention or treatment of pneumoconioses such as silicosis, asbestosis, and coal worker's pneumoconiosis. However, studies regarding selenium and occupational lung diseases are rare. The purpose of this study is to conduct a mini-review regarding the relationship between selenium and exposure to fibrogenic mineral dust with emphasis on epidemiological studies. We carried out a systematic literature search of English published studies on selenium and exposure to fibrogenic mineral dust. We found four epidemiological studies. Reviewed studies show that selenium is lower in individuals exposed to fibrogenic mineral dust. However, three out of the four reviewed studies could not confirm cause-and-effect relationships between low selenium status and exposure to fibrogenic mineral dust. This mini-review underscores the need for large follow-up and mechanistic studies for selenium to further elucidate its therapeutic effects.

  6. Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

    PubMed

    Kobayashi, Fumihisa; Maki, Teruya; Kakikawa, Makiko; Yamada, Maromu; Puspitasari, Findya; Iwasaka, Yasunobu

    2015-05-01

    Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area. PMID:25735592

  7. Wind barriers suppress fugitive dust and soil-derived airborne particles in arid regions

    SciTech Connect

    Grantz, D.A.; Vaughn, D.L.; Farber, R.J.; Kim, B.; Ashbaugh, L.; Van Curen, T.; Campbell, R.

    1998-07-01

    Areas of abandoned agricultural land in the Antelope Valley, western Mojave (high) desert of California have proven in the previous studies to be recalcitrant to conventional tillage and revegetation strategies designed to suppress wind erosion of soil and transport of sediment and fugitive dust. These areas represented a continuing source of drifting sand and of coarse and respirable suspended particulate matter. The traditional techniques failed because furrows collapsed and the water holding capacity of the overburden was too low to support seed germination and transplant survival. In this study a variety of wind barriers were evaluated for suppression of sediment transport. Airborne particles were measured with an array of coarse particle samplers at heights of 0.2, 1.0, and 2.0 m above the soil surface. Discrete artificial wind barriers, consisting of widely spaced roughness elements were effective in suppressing fugitive emissions. Wind fences established along the leeward edge of an area of blowing sand, perpendicular to the prevailing wind, significantly decreased fugitive emissions. Control was greatest and precision of the measurements was highest under high wind conditions. These techniques provide rapid and effective suppression of fugitive emissions of soil-derived particles under conditions that resist conventional tillage and revegetation techniques. A simple, indirect procedure for determining local wind velocity erosion thresholds requiring only sampling of wind run and suspended particulate mass compared favorably with direct measurement of saltation as a function of wind velocity.

  8. Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

    PubMed

    Kobayashi, Fumihisa; Maki, Teruya; Kakikawa, Makiko; Yamada, Maromu; Puspitasari, Findya; Iwasaka, Yasunobu

    2015-05-01

    Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area.

  9. Clinically important respiratory effects of dust exposure and smoking in British coal miners

    SciTech Connect

    Marine, W.M.; Gurr, D.; Jacobsen, M.

    1988-01-01

    A unique data set of 3380 British coal miners has been reanalyzed with major focus on nonpneumoconiotic respiratory conditions. The aim was to assess the independent contribution of smoking and exposure to respirable dust to clinically significant measures of respiratory dysfunction. Exposure to coal-mine dust was monitored over a 10-yr period. Medical surveys provided estimates of prior dust exposure and recorded respiratory symptoms. Each man's FEV1 was compared with the level predicted for his age and height by an internally derived prediction equation for FEV1. Four respiratory indices were considered at the end of the 10-yr period: FEV1 less than 80%, chronic bronchitis, chronic bronchitis with FEV1 less than 80%, and FEV1 less than 65%. Results were uniformly incorporated into logistic regression equations for each condition. The equations include coefficients for age, dust, and when indicated, an interaction term for age and dust. Dust-related increases in prevalence of each of the 4 conditions were statistically significant and were similar for smokers and nonsmokers at the mean age (47 yr). There was no evidence that smoking potentiates the effect of exposure to dust. Estimates of prevalences at the mean age of all 4 measures of respiratory dysfunction were greater in smokers. At intermediate and high dust exposure the prevalence of the 4 conditions in nonsmokers approached the prevalence in smokers at hypothetically zero dust exposure. Both smoking and dust exposure can cause clinically important respiratory dysfunction and their separate contributions to obstructive airway disease in coal miners appear to be additive.

  10. A Theoretical Framework for Understanding the Effects of Saharan Mineral Dust Aerosols on African Easterly Waves

    NASA Astrophysics Data System (ADS)

    Nathan, T. R.; Grogan, D.; Chen, S.

    2013-12-01

    Studies have shown that a large fraction of the intense hurricanes observed over the Atlantic Ocean originate as African easterly waves (AEWs). Of the many processes that affect the propagation, growth and structure of AEWs, the effects of Saharan mineral dust aerosols on AEWs remains an outstanding scientific problem. With this in mind, a new theoretical framework is presented that illuminates causal relationships between Saharan dust and the linear dynamics of AEWs. The framework is built on a quasi-geostrophic system governed by coupled equations for potential vorticity, temperature, and dust continuity. The radiative-dust heating rate accounts for both shortwave and longwave radiative transfer. The source of dust is due to surface emission, which depends on surface wind; the sinks of dust are due to sedimentation and dry deposition. A perturbation analysis yields analytical expressions for the propagation and growth characteristics of the model's AEWs. These expressions are functions of vertically and meridionally averaged wave activity, which depends on wave spatial structure, dust-radiative heating, and the background distributions of wind, temperature, and dust mixing ratio. More specifically, the propagation and growth of the AEWs depend on the amount of dust lofted from the surface by the wind, and the meridional and vertical gradients of the basic state dust distribution, which are modulated by the Doppler-shifted frequency. Idealized cases are presented that show the effects of Saharan dust on the propagation, group velocity, growth, structure, and wave fluxes of AEWs. The clarity of the expressions connecting dust aerosols to the linear properties of AEWs provides an important interpretive tool for analyzing results obtained from comprehensive model simulations of AEWs, such as those produced by the Weather Research and Forecasting (WRF) model.

  11. The spatial distribution of mineral dust and its shortwave radiative forcing over North Africa. Modeling sensitivities to dust emissions and aerosol size treatments

    SciTech Connect

    Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Johnson, Ben; McFarlane, Sally A.; Gustafson, William I.; Fast, Jerome D.; Easter, Richard C.

    2010-09-20

    A fully coupled meteorology-chemistry-aerosol model (WRF-Chem) with the implementation of two dust emission schemes (GOCART and DUSTRAN) into two aerosol models (MADE/SORGAM and MOSAIC) is applied over North Africa to investigate the modeling sensitivities to dust emissions and aerosol size treatments in simulating mineral dust and its shortwave (SW) radiative forcing. Model results of the spatial distribution of mineral dust and its radiative forcing are evaluated using measurements from the AMMA SOP0 campaign in January and February of 2006 over North Africa. Our study suggests that the size distribution of emitted dust can result in significant differences (up to 100%) in simulating mineral dust and its SW radiative forcing. With the same dust emission and dry deposition processes, two aerosol models, MADE/SORGAM and MOSAIC, can yield large difference in size distributions of dust particles due to their different aerosol size treatments using modal and sectional approaches respectively. However, the difference between the two aerosol models in simulating the mass concentrations and the SW radiative forcing of mineral dust is small (< 10%). The model simulations show that mineral dust increases AOD by a factor of 2, heats the lower atmosphere (1-3 km) with a maximum rate of 0.7±0.5 K day-1 below 1 km, and reduces the downwelling SW radiation by up to 25 W m-2 on 24-hour average at surface, highlighting the importance of including dust radiative impact in understanding the regional climate of North Africa. When compared to the available measurements, WRF-Chem simulations can generally capture the measured features of mineral dust and its radiative properties over North Africa, suggesting that the model can be used to perform more extensive simulations of regional climate over North Africa.

  12. Discrimination of hydrothermal alteration mineral assemblages at Virginia City, Nevada, using the airborne imaging spectrometer

    NASA Technical Reports Server (NTRS)

    Hutsinpiller, Amy

    1988-01-01

    The purpose of this study is to use airborne imaging spectrometer data to discriminate hydrothermal alteration mineral assemblages associated with silver and gold mineralization at Virginia City, NV. The data is corrected for vertical striping and sample gradients, and converted to flat-field logarithmic residuals. Log residual spectra from areas known to be altered are compared to field spectra for kaolinitic, illitic, sericitic, and propylitic alteration types. The areal distributions of these alteration types are estimated using a spectral matching technique. Both visual examination of spectra and the matching techniques are effective in distinguishing kaolinitic, illitic, and propylitic alteration types from each other. However, illitic and sericitic alteration cannot be separated using these techniques because the spectra of illite and sericite are very similar. A principal components analysis of 14 channels in the 2.14-2.38 micron wavelength region is also successful in discriminating and mapping illitic, kaolinitic, and propylitic alteration types.

  13. Optimization of the concentration optics of the Martian airborne dust sensor for MetNet space mission

    NASA Astrophysics Data System (ADS)

    Cortés, F.; González, A.; de Castro, A. J.; López, F.

    2012-06-01

    Martian atmosphere contains a significant and rapidly changing load of suspended dust that never drops to zero. The main component of Martian aerosol is micron-sized dust thought to be a product of soil weathering. Although airborne dust plays a key role in Martian climate, the basic physical properties of these aerosols are still poorly known. The scope of Mars MetNet Mission is to deploy several tens of mini atmospheric stations on the Martian surface. MEIGA-MetNet payload is the Spanish contribution in MetNet. Infrared Laboratory of University Carlos III (LIR-UC3M) is in charge of the design and development of a micro-sensor for the characterization of airborne dust. This design must accomplish with a strict budget of mass and power, 45 g and 1 W respectively. The sensor design criteria have been obtained from a physical model specifically developed for optimizing IR local scattering. The model calculates the spectral power density scattered and detected between 1 and 5 μm by a certain particle distribution and sensor configuration. From model calculations a modification based on the insertion of a compound ellipsoidal concentrator (CEC) has appeared as necessary. Its implementation has multiplied up to 100 the scattered optical power detected, significantly enhancing the detection limits of the sensor.

  14. A brief report of gram-negative bacterial endotoxin levels in airborne and settled dusts in animal confinement buildings

    SciTech Connect

    Thedell, T.D.; Mull, J.C.; Olenchock, S.A.

    1980-01-01

    Gram-negative bacterial endotoxins, implicated in adverse worker health responses, were found in settled and airborne dust samples obtained from poultry and swine confinement units. Results of the Limulus amebocyte lysate gel test found endotoxin levels in dust samples ranged from 4.5 to 47.7 micrograms of FDA Klebsiella endotoxin equivalents/gm. Differences in endotoxin levels between dust samples may have been due to variables in time, geographic locations, confined animals, confinement buildings and equipment, and methods of sample collection. Animal confinement workers are potentially exposed to large amounts of gram-negative bacterial endotoxins; however, the respiratory health effects of such exposures to animal confinement workers have yet to be determined.

  15. Characterization of minerals in air dust particles in the state of Tamilnadu, India through ftir spectroscopy

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, R.; Rajkumar, P.

    2013-08-01

    The abstract of this paper explains the presence of minerals in air which causes great concern regarding public health issues. The spectroscopic investigation of air dust particles of several samples in various locations in the state of Tamilnadu, India is reported. Qualitative analyses were carried out to determine the major and minor constituent minerals present in the samples based on the FTIR absorption peaks. This study also identified the minerals like quartz, asbestos, kaolinite, calcite, hematite, montmorillonite, nacrite and several other trace minerals in the air dust particles. The presents of quartz is mainly found in all the samples invariably. Hence the percentage of quartz and its crystalline nature were determined with the help of extinction co-efficient and crystallinity index respectively.

  16. Kinetics of Heterogeneous Reaction of Sulfur Dioxide on Authentic Mineral Dust: Effects of Relative Humidity and Hydrogen Peroxide.

    PubMed

    Huang, Liubin; Zhao, Yue; Li, Huan; Chen, Zhongming

    2015-09-15

    Heterogeneous reaction of SO2 on mineral dust seems to be an important sink for SO2. However, kinetic data about this reaction on authentic mineral dust are scarce and are mainly limited to low relative humidity (RH) conditions. In addition, little is known about the role of hydrogen peroxide (H2O2) in this reaction. Here, we investigated the uptake kinetics of SO2 on three authentic mineral dusts (i.e., Asian mineral dust (AMD), Tengger desert dust (TDD), and Arizona test dust (ATD)) in the absence and presence of H2O2 at different RHs using a filter-based flow reactor, and applied a parameter (effectiveness factor) to the estimation of the effective surface area of particles for the calculation of the corrected uptake coefficient (γc). We found that with increasing RH, the γc decreases on AMD particles, but increases on ATD and TDD particles. This discrepancy is probably due to the different mineralogy compositions and aging extents of these dust samples. Furthermore, the presence of H2O2 can promote the uptake of SO2 on mineral dust at different RHs. The probable explanations are that H2O2 rapidly reacts with SO2 on mineral dust in the presence of adsorbed water, and OH radicals, which can be produced from the heterogeneous decomposition of H2O2 on the mineral dust, immediately react with adsorbed SO2 as well. Our results suggest that the removal of SO2 via the heterogeneous reaction on mineral dust is an important sink for SO2 and has the potential to alter the physicochemical properties (e.g., ice nucleation ability) of mineral dust particles in the atmosphere. PMID:26281003

  17. Kinetics of Heterogeneous Reaction of Sulfur Dioxide on Authentic Mineral Dust: Effects of Relative Humidity and Hydrogen Peroxide.

    PubMed

    Huang, Liubin; Zhao, Yue; Li, Huan; Chen, Zhongming

    2015-09-15

    Heterogeneous reaction of SO2 on mineral dust seems to be an important sink for SO2. However, kinetic data about this reaction on authentic mineral dust are scarce and are mainly limited to low relative humidity (RH) conditions. In addition, little is known about the role of hydrogen peroxide (H2O2) in this reaction. Here, we investigated the uptake kinetics of SO2 on three authentic mineral dusts (i.e., Asian mineral dust (AMD), Tengger desert dust (TDD), and Arizona test dust (ATD)) in the absence and presence of H2O2 at different RHs using a filter-based flow reactor, and applied a parameter (effectiveness factor) to the estimation of the effective surface area of particles for the calculation of the corrected uptake coefficient (γc). We found that with increasing RH, the γc decreases on AMD particles, but increases on ATD and TDD particles. This discrepancy is probably due to the different mineralogy compositions and aging extents of these dust samples. Furthermore, the presence of H2O2 can promote the uptake of SO2 on mineral dust at different RHs. The probable explanations are that H2O2 rapidly reacts with SO2 on mineral dust in the presence of adsorbed water, and OH radicals, which can be produced from the heterogeneous decomposition of H2O2 on the mineral dust, immediately react with adsorbed SO2 as well. Our results suggest that the removal of SO2 via the heterogeneous reaction on mineral dust is an important sink for SO2 and has the potential to alter the physicochemical properties (e.g., ice nucleation ability) of mineral dust particles in the atmosphere.

  18. Global Modeling of Mineral Dust and its Optical Thickness

    NASA Technical Reports Server (NTRS)

    Ginoux, Paul A.; Chin, Mian; Tegen, Ina; Herman, Jay R.; Torres, Omar; Winker, David; Holben, Brent; Lin, S.-J.

    1999-01-01

    Global distribution of dust in the atmosphere has been simulated using the NASA Goddard chemical transport model (GEOS-CTM) to help retrieve the aerosol optical thickness from TOMS absorbing aerosol index. The model contains a dust module which accounts for sources and removal processes. The transport is driven by the assimilated meteorological fields generated by the NASA Goddard Earth Observing System Data Assimilation System (GEOS DAS). One of the key parameters, in the retrieval algorithm of optical thickness from Total Ozone Mapping Spectrometer (TOMS) data, is the vertical profile of aerosols. During the period 10- 19 September 1994, Lidar on-space Technology Experiment (LITE) was flown on space shuttle Discovery. The 53 hours of data collected cover the lower atmosphere from the earth surface to 20 kilometers altitude and from 57 N to 57 S with a high resolution of about 15 meters. The model results are compared with LITE data over the source regions of dust (Africa, Middle East, Asia, Australia) and in the remote troposphere (Atlantic and Pacific). The simulated horizontal distribution is compared with TOMS absorbing aerosol index. Finally the calculated optical thickness will be assessed with ground based sun-photometers (AERONET).

  19. Health effects of mineral dusts, Volume 28: Proceedings

    SciTech Connect

    Guthrie, G.D. Jr.; Mossman, B.T.

    1993-12-31

    The processes that lead to the development of disease (or pathogenesis) by minerals very likely occur at or near the mineral-fluid interface. Thus the field of ``mineral-induced pathogenesis`` is a prime candidate for interdisciplinary research, involving mineral scientists, health scientists, petrologists, pathologists, geochemists, biochemists, and surface scientists, to name a few. This review volume and the short course upon which it was based are intended to provide some of the necessary tools for the researcher interested in this area of interdisciplinary research. The chapters present several of the important problems, concepts, and approaches from both the geological and biological ends of the spectrum. These two extremes are partially integrated throughout the book by cross-referencing between chapters. Chapter 1 also presents a general introduction into the ways in which these two areas overlap. The final chapter of this book discusses some of the regulatory aspects of minerals. A glossary is included at the end of this book, because the complexity of scientific terms in the two fields can thwart even the most enthusiastic of individuals. Individual reports have been processed separately for the database.

  20. Understanding ice nucleation characteristics of selective mineral dusts suspended in solution

    NASA Astrophysics Data System (ADS)

    Kumar, Anand; Marcolli, Claudia; Kaufmann, Lukas; Krieger, Ulrich; Peter, Thomas

    2016-04-01

    Introduction & Objectives Freezing of liquid droplets and subsequent ice crystal growth affects optical properties of clouds and precipitation. Field measurements show that ice formation in cumulus and stratiform clouds begins at temperatures much warmer than those associated with homogeneous ice nucleation in pure water, which is ascribed to heterogeneous ice nucleation occurring on the foreign surfaces of ice nuclei (IN). Various insoluble particles such as mineral dust, soot, metallic particles, volcanic ash, or primary biological particles have been suggested as IN. Among these the suitability of mineral dusts is best established. The ice nucleation ability of mineral dust particles may be modified when secondary organic or inorganic substances are accumulating on the dust during atmospheric transport. If the coating is completely wetting the mineral dust particles, heterogeneous ice nucleation occurs in immersion mode also below 100 % RH. A previous study by Kaufmann (PhD Thesis 2015, ETHZ) with Hoggar Mountain dust suspensions in various solutes (ammonium sulfate, PEG, malonic acid and glucose) showed reduced ice nucleation efficiency (in immersion mode) of the particles. Though it is still quite unclear of how surface modifications and coatings influence the ice nucleation activity of the components present in natural dust samples. In view of these results we run freezing experiments using a differential scanning calorimeter (DSC) with the following mineral dust particles suspended in pure water and ammonium sulfate solutions: Arizona Test Dust (ATD), microcline, and kaolinite (KGa-2, Clay Mineral Society). Methodology Suspensions of mineral dust samples (ATD: 2 weight%, microcline: 5% weight, KGa-2: 5% weight) are prepared in pure water with varying solute concentrations (ammonium sulfate: 0 - 10% weight). 20 vol% of this suspension plus 80 vol% of a mixture of 95 wt% mineral oil (Aldrich Chemical) and 5 wt% lanolin (Fluka Chemical) is emulsified with a

  1. Light-Induced SO2 Photochemistry at the Mineral Dust Surface

    NASA Astrophysics Data System (ADS)

    Styler, S. A.; Doussin, J.; Formenti, P.; Donaldson, D.

    2013-12-01

    The uptake of SO2 by mineral dust is believed to proceed first by formation of surface-bound sulfite, which can subsequently be oxidized to sulfate not only by co-sorbed O3 and NO2 but also by photooxidants such as Fe and Ti present within the dust itself. In the first phase of this study, we investigated the effect of light upon SO2 uptake by Fe2O3, TiO2, illite, feldspar, and mineral dust samples obtained from Niger, Tunisia, and China. We determined the initial uptake coefficient of SO2 at the surface of dust samples under both light and dark conditions using a photochemical Knudsen cell, and then measured the relative quantities of sulfite and sulfate formed at the surface of these films using ion chromatography. In the second phase of this study, which was performed in the CESAM atmospheric chamber, we explored the possibility that light-induced production of surface-sorbed sulfate might result in enhanced dust hygroscopicity by measuring changes in dust particle size distribution as a function of exposure to SO2 and light under a range of relative humidity conditions.

  2. Atmospheric mineral dust in dryland ecosystems: Applications of environmental magnetism

    NASA Astrophysics Data System (ADS)

    Reynolds, Richard L.; Goldstein, Harland L.; Miller, Mark E.

    2010-07-01

    Magnetic properties of shallow (<10-cm depth), fine-grained surficial sediments contrast greatly with those of immediately underlying bedrock across much of the dry American Southwest. At 26 study sites in fine-grained (<63 μm) surficial sediments isolated from alluvial inputs, isothermal remanent magnetization (IRM; mean of 67 samples = 6.72 × 10-3 Am2 kg-1) is more than two orders of magnitude greater than that for underlying Paleozoic and Mesozoic sedimentary rocks. This contrast is mainly caused by the presence of silt-size, titanium-bearing magnetite particles in the surficial deposits and their absence in bedrock. Because of their size, composition, and isolated location, the magnetite particles represent a component of atmospheric dust likely deposited over the past few centuries. The positive correlation of sediment-IRM values with amounts of potential plant nutrients reveals the importance of atmospheric dust to soil fertility over much of the American Southwest. Subsequent disturbance of landscapes, by domestic livestock grazing as an example, commonly results in wind erosion, which then depletes exposed surfaces of original aeolian magnetite and associated fine-grained sediment. Declines in soil fertility and water-holding capacity in these settings can be estimated in some field settings via decreases in magnetic susceptibility, relative to nearby undisturbed areas. Along gentle hillslope gradients of the Colorado Plateau, field measures for aeolian magnetite demonstrate that the redistribution of deposited atmospheric dust influences landscape-level patterns in the distribution of invasive exotic plant species. Our results indicate that environmental magnetism has high potential for assessing the development and degradation of dry landscapes elsewhere.

  3. An Assessment of the Surface Longwave Direct Radiative Effect of Airborne Saharan Dust During the NAMMA Field Campaign

    NASA Technical Reports Server (NTRS)

    Hansell, R. A.; Tsay, S. C.; Ji, Q.; Hsu, N. C.; Jeong, M. J.; Wang, S. H.; Reid, J. S.; Liou, K. N.; Ou, S. C.

    2010-01-01

    In September 2006, NASA Goddard s mobile ground-based laboratories were deployed to Sal Island in Cape Verde (16.73degN, 22.93degW) to support the NASA African Monsoon Multidisciplinary Analysis (NAMMA) field study. The Atmospheric Emitted Radiance Interferometer (AERI), a key instrument for spectrally characterizing the thermal IR, was used to retrieve the dust IR aerosol optical depths (AOTs) in order to examine the diurnal variability of airborne dust with emphasis on three separate dust events. AERI retrievals of dust AOT are compared with those from the coincident/collocated multifilter rotating shadow-band radiometer (MFRSR), micropulse lidar (MPL), and NASA Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) sensors. The retrieved AOTs are then inputted into the Fu-Liou 1D radiative transfer model to evaluate local instantaneous direct longwave radiative effects (DRE(sub LW)) of dust at the surface in cloud-free atmospheres and its sensitivity to dust microphysical parameters. The top-of-atmosphere DRE(sub LW) and longwave heating rate profiles are also evaluated. Instantaneous surface DRE(sub LW) ranges from 2 to 10 W/sq m and exhibits a strong linear dependence with dust AOT yielding a DRE(sub LW) of 16 W/sq m per unit dust AOT. The DRE(sub LW) is estimated to be approx.42% of the diurnally averaged direct shortwave radiative effect at the surface but of opposite sign, partly compensating for the shortwave losses. Certainly nonnegligible, the authors conclude that DRE(sub LW) can significantly impact the atmospheric energetics, representing an important component in the study of regional climate variation.

  4. Mineral phases and metals in baghouse dust from secondary aluminum production

    EPA Science Inventory

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78...

  5. Mineral Dust Impact on Short- and Long-Wave Radiation and Comparison with Ceres Measurements

    NASA Astrophysics Data System (ADS)

    Romano, Salvatore; Perrone, Maria Rita

    2016-06-01

    Clear-sky downward and upward radiative flux measurements both in the short- and in the long-wave spectral range have been used to estimate and analyze the radiation changes at the surface due to the mineral dust advection at a Central Mediterranean site. Then, short- and long-wave radiative fluxes retrieved from the CERES (Clouds and the Earth's Radiant Energy System) radiometer sensors operating on board the EOS (Earth Observing System) AQUA and TERRA platforms have been used to evaluate the mineral dust radiative impact at the top of the atmosphere. Satellite-derived radiative fluxes at the surface have been compared with corresponding ground-based flux measurements, collocated in space and time, to better support and understand the desert dust radiative impact. Results referring to the year 2012 are reported.

  6. [Effect of water sprinkling on total dust and mineral fiber concentration during serpentine asbestos processing].

    PubMed

    Woźniak, H; Wiecek, E; Pelc, W; Dobrucka, D; Opalska, B

    1993-01-01

    By means of personal air sampler and Fibre Monitor FM-7400 concentrations of total dust and respirable mineral fibre were measured at work-posts, after sprinkling places with the highest emission of dust, in the plant where serpentine asbestos, used as road stone, was processed. It was found that due to sprinkling mean concentrations of total dust during a shift decreased by 1.5 (at inspection post) to 13.5 times at the post where crushing and sorting machines were served (before sprinkling -29.7 mg/m3 and after 2.2 mg/m3). It was found, at the same time, that sprinkling no decreased the concentration of mineral fibres.

  7. How important are cyclones for emitting mineral dust aerosol in North Africa?

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Schepanski, K.; Knippertz, P.; Heinold, B.; Tegen, I.

    2013-12-01

    This study presents the first quantitative estimate of the mineral dust emission associated to atmospheric depressions and migrating, long-lived cyclones in North Africa. Results from a tracking algorithm are combined with dust emission flux calculations based on ERA-Interim data from the European Centre for Medium-Range Weather Forecasts for 1989-2008. The results highlight that depressions are abundant and associated with 55% of the dust emission amount annually and spatially averaged over North African dust sources. Even larger contributions to dust emission from depressions are found south of the Atlas Mountains during spring with regionally up to 90%. It is spring when the largest monthly totals of 250-380 g m-2 of dust emission occur in North Africa. The remaining months have a total dust emission smaller than 80 g m-2. In summer, depressions, particularly Saharan heat lows, coincide with up to 90% of the seasonal total dust emission over wide areas of North Africa. In contrast to depressions, migrating cyclones that live for more than two days are rare and are associated to 4% of the annual and spatial dust emission average. Migrating cyclones over North Africa occur primarily in spring north of 20° N with eastwards trajectories and typical life times of three to seven days. Regionally larger seasonal totals of dust emission are associated to cyclones with up to 25% over Libya. In summer, near-surface signatures of African Easterly Waves (AEWs) emit regionally up to 15% of the total emission. The diurnal cycle of dust emission underlines that emission associated to cyclones at mid-day is substantially larger than at night by a factor of three to five. Soil moisture weakens dust emission during cyclone passage by 10%. Despite the overall small contribution of migrating cyclones to dust emission, cyclones coincide with particularly intense dust emission events exceeding the climatological mean flux by a factor of four to eight. This implies, that both

  8. Characterizing Mineral Dust from the Arabian Coast of the Red Sea

    NASA Astrophysics Data System (ADS)

    Puthan Purakkal, J.; Stenchikov, G. L.; Engelbrecht, J. P.

    2014-12-01

    The Arabian Peninsula is one of the Earth's major sources of atmospheric dust. Along with profound negative effects on human activity and natural processes in this region, dust is an important nutrient source for the oligothrophic northern Red Sea. From preliminary observations it is estimated that some 18-20 major dust storms per year deposit about 6 Mt of mineral dust into the Red Sea. To better understand the optical properties, health, and ecological impacts of dust, we study the mineralogical, chemical and morphological properties of surface soil samples collected at prevbiously identified potential dust sources along the Arabian coast of the Red Sea. Many of these dust sources lie within a narrow coastal region and because of their proximity to the Red Sea, are important contributors to the dust/nutrient balance, during both dusty and fair weather conditions. Bulk samples were collected from the top 10 mm of soils from three sites along the Arabian coast of the Red Sea. The soil samples were sieved to separate the < 38μm particle fractions for chemical and mineralogical analysis. X-ray diffractometry (XRD) was applied to measure the mineral content of the dust. The chemical composition of individual particles was analyzed using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). From the XRD analysis of the sieved samples from An Masayat (23.3322 N, 38.9481 E), Buthna (23.2960 N, 38.9384 E) and Rabugh pipeline Road (23.292 N, 38.91 E), it was found that the dust was composed largely of hematite, goethite, calcite, dolomite, quartz, chlorite, muscovite, amphibole, epidote and plagioclase. Our results are being compared to, and show similarities to those of Engelbrecht et al. , collected at 15 Middle East sites. Both the mineralogical content and chemical composition of samples bear the signatures of the regional geology. Engelbrecht, J. P., McDonald, E. V., Gillies, J. A., Jayanty, R. K. M., Casuccio, G., and Gertler, A. W., 2009

  9. Assessments for the impact of mineral dust on the meningitis incidence in West Africa

    NASA Astrophysics Data System (ADS)

    Martiny, Nadège; Chiapello, Isabelle

    2013-05-01

    Recently, mineral dust has been suspected to be one of the important environmental risk factor for meningitis epidemics in West Africa. The current study is one of the first which relies on long-term robust aerosol measurements in the Sahel region to investigate the possible impact of mineral dust on meningitis cases (incidence). Sunphotometer measurements, which allow to derive aerosol and humidity parameters, i.e., aerosol optical thickness, Angström coefficient, and precipitable water, are combined with quantitative epidemiological data in Niger and Mali over the 2004-2009 AMMA (African Monsoon Multidisciplinary Analysis) program period. We analyse how the extremely high aerosol loads in this region may influence both the calendar (onset, peaks, end) and the intensity of meningitis. We highlight three distinct periods: (i) from November to December, beginning of the dry season, humidity is weak, there is no dust and no meningitis cases; (ii) from January to April, humidity is still weak, but high dust loads occur in the atmosphere and this is the meningitis season; (iii) from May to October, humidity is high and there is no meningitis anymore, in presence of dust or not, which flow anyway in higher altitudes. More specifically, the onset of the meningitis season is tightly related to mineral dust flowing close to the surface at the very beginning of the year. During the dry, and the most dusty season period, from February to April, each meningitis peak is preceded by a dust peak, with a 0-2 week lead-time. The importance (duration, intensity) of these meningitis peaks seems to be related to that of dust, suggesting that a cumulative effect in dust events may be important for the meningitis incidence. This is not the case for humidity, confirming the special contribution of dust at this period of the year. The end of the meningitis season, in May, coincides with a change in humidity conditions related to the West African Monsoon. These results, which are

  10. Effects of mineral dust on global atmospheric nitrate concentrations

    NASA Astrophysics Data System (ADS)

    Karydis, Vlassis; Tsimpidi, Alexandra; Astitha, Marina; Lelieveld, Jos

    2014-05-01

    Inorganic particulate nitrate contributes significantly to the total aerosol mass. While nitrate is predominantly present in the submicron mode, coarse mode aerosol nitrate can also be produced by adsorption of nitric acid onto soil particles. Naturally emitted particles affect the phase partitioning of nitrate, especially in areas where dust comprises a significant portion of total particulate matter, and the simulation of these effects can considerably improve model predictions. However, most thermodynamic models used in global studies lack a realistic treatment of crustal species. This work aims to improve the representation of nitrate aerosols in the global chemistry climate model EMAC, and addresses the shortcomings of previous models. EMAC calculates the aerosol microphysics and gas/aerosol partitioning by using the GMXe aerosol module. The aerosol size distribution is described by 7 interacting lognormal modes (4 hydrophilic and 3 hydrophobic modes). An advanced dust emission module also accounts for the soil particle size distribution of different deserts worldwide. Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model which considers the interaction of K(+), Ca(+2), Mg(+2), NH4(+), Na(+), SO4(-2), NO3(-), Cl(-), H2O aerosol components. The EMAC model is tested in long-term simulations covering the years 2005-2008. Model predictions are compared with data from the European network EMEP, the IMPROVE network in North America, and the EANET Network in East Asia.

  11. Depletion of tropospheric ozone associated with mineral dust outbreaks.

    PubMed

    Soler, Ruben; Nicolás, J F; Caballero, S; Yubero, E; Crespo, J

    2016-10-01

    From May to September 2012, ozone reductions associated with 15 Saharan dust outbreaks which occurred between May to September 2012 have been evaluated. The campaign was performed at a mountain station located near the eastern coast of the Iberian Peninsula. The study has two main goals: firstly, to analyze the decreasing gradient of ozone concentration during the course of the Saharan episodes. These gradients vary from 0.2 to 0.6 ppb h(-1) with an average value of 0.39 ppb h(-1). The negative correlation between ozone and coarse particles occurs almost simultaneously. Moreover, although the concentration of coarse particles remained high throughout the episode, the time series shows the saturation of the ozone loss. The highest ozone depletion has been obtained during the last hours of the day, from 18:00 to 23:00 UTC. Outbreaks registered during this campaign have been more intense in this time slot. The second objective is to establish from which coarse particle concentration a significant ozone depletion can be observed and to quantify this reduction. In this regard, it has been confirmed that when the hourly particle concentration recorded during the Saharan dust outbreaks is above the hourly particle median values (N > N-median), the ozone concentration reduction obtained is statistically significant. An average ozone reduction of 5.5 % during Saharan events has been recorded. In certain cases, this percentage can reach values of higher than 15 %. PMID:27376369

  12. The immersion freezing behavior of mineral dust particles mixed with biological substances

    NASA Astrophysics Data System (ADS)

    Augustin-Bauditz, S.; Wex, H.; Denjean, C.; Hartmann, S.; Schneider, J.; Schmidt, S.; Ebert, M.; Stratmann, F.

    2015-10-01

    Biological particles such as bacteria, fungal spores or pollen are known to be efficient ice nucleating particles. Their ability to nucleate ice is due to ice nucleation active macromolecules (INM). It has been suggested that these INM maintain their nucleating ability even when they are separated from their original carriers. This opens the possibility of an accumulation of such INM in e.g., soils, resulting in an internal mixture of mineral dust and INM. If particles from such soils which contain biological INM are then dispersed into the atmosphere due to wind erosion or agricultural processes, they could induce ice nucleation at temperatures typical for biological substances, i.e., above -20 up to almost 0 °C. To explore this hypothesis, we performed a measurement campaign within the research unit INUIT, where we investigated the ice nucleation behavior of mineral dust particles internally mixed with INM. Specifically, we mixed a pure mineral dust sample (illite-NX) with ice active biological material (birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). To characterize the mixing state of the generated aerosol we used different methods which will also be discussed. We found that internally mixed particles, containing ice active biological material, follow the ice nucleation behavior observed for the purely biological particles, i.e. freezing occurs at temperatures at which mineral dusts themselves are not yet ice active. It can be concluded that INM located on a mineral dust particle determine the freezing behavior of that particle.

  13. Chemical speciation of size-segregated floor dusts and airborne magnetic particles collected at underground subway stations in Seoul, Korea.

    PubMed

    Jung, Hae-Jin; Kim, BoWha; Malek, Md Abdul; Koo, Yong Sung; Jung, Jong Hoon; Son, Youn-Suk; Kim, Jo-Chun; Kim, HyeKyoung; Ro, Chul-Un

    2012-04-30

    Previous studies have reported the major chemical species of underground subway particles to be Fe-containing species that are generated from wear and friction processes at rail-wheel-brake and catenaries-pantographs interfaces. To examine chemical composition of Fe-containing particles in more details, floor dusts were collected at five sampling locations of an underground subway station. Size-segregated floor dusts were separated into magnetic and non-magnetic fractions using a permanent magnet. Using X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), iron metal, which is relatively harmless, was found to be the dominating chemical species in the floor dusts of the <25 μm size fractions with minor fractions of Mg, Al, Si, Ca, S, and C. From SEM analysis, the floor dusts of the <25 μm size fractions collected on railroad ties appeared to be smaller than 10 μm, indicating that their characteristics should somewhat reflect the characteristics of airborne particles in the tunnel and the platform. As most floor dusts are magnetic, PM levels at underground subway stations can be controlled by removing magnetic indoor particles using magnets. In addition, airborne subway particles, most of which were smaller than 10 μm, were collected using permanent magnets at two underground subway stations, namely Jegi and Yangjae stations, in Seoul, Korea. XRD and SEM/EDX analyses showed that most of the magnetic aerosol particles collected at Jegi station was iron metal, whereas those at Yangjae station contained a small amount of Fe mixed with Na, Mg, Al, Si, S, Ca, and C. The difference in composition of the Fe-containing particles between the two subway stations was attributed to the different ballast tracks used. PMID:22381374

  14. Chemical speciation of size-segregated floor dusts and airborne magnetic particles collected at underground subway stations in Seoul, Korea.

    PubMed

    Jung, Hae-Jin; Kim, BoWha; Malek, Md Abdul; Koo, Yong Sung; Jung, Jong Hoon; Son, Youn-Suk; Kim, Jo-Chun; Kim, HyeKyoung; Ro, Chul-Un

    2012-04-30

    Previous studies have reported the major chemical species of underground subway particles to be Fe-containing species that are generated from wear and friction processes at rail-wheel-brake and catenaries-pantographs interfaces. To examine chemical composition of Fe-containing particles in more details, floor dusts were collected at five sampling locations of an underground subway station. Size-segregated floor dusts were separated into magnetic and non-magnetic fractions using a permanent magnet. Using X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), iron metal, which is relatively harmless, was found to be the dominating chemical species in the floor dusts of the <25 μm size fractions with minor fractions of Mg, Al, Si, Ca, S, and C. From SEM analysis, the floor dusts of the <25 μm size fractions collected on railroad ties appeared to be smaller than 10 μm, indicating that their characteristics should somewhat reflect the characteristics of airborne particles in the tunnel and the platform. As most floor dusts are magnetic, PM levels at underground subway stations can be controlled by removing magnetic indoor particles using magnets. In addition, airborne subway particles, most of which were smaller than 10 μm, were collected using permanent magnets at two underground subway stations, namely Jegi and Yangjae stations, in Seoul, Korea. XRD and SEM/EDX analyses showed that most of the magnetic aerosol particles collected at Jegi station was iron metal, whereas those at Yangjae station contained a small amount of Fe mixed with Na, Mg, Al, Si, S, Ca, and C. The difference in composition of the Fe-containing particles between the two subway stations was attributed to the different ballast tracks used.

  15. 76 FR 30878 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... FR 64412), extended January 14, 2011 (76 FR 2617) and May 4, 2011 (76 FR 25277), is further extended. All comments must be received or postmarked by midnight Eastern Daylight Saving Time on June 20, 2011... Continuous Personal Dust Monitors. This extension gives commenters additional time to review and comment...

  16. Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

    DOE PAGES

    Sudarchikova, Natalia; Mikolajewicz, Uwe; Timmreck, C.; O'Donnell, D.; Schurgers, G.; Sein, Dmitry; Zhang, Kai

    2015-05-19

    The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide unique information about deposition of aeolian dust particles transported over long distances. These cores are a palaeoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol–climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission,more » atmospheric transport and precipitation, which will help to interpret palaeodata from Antarctic ice cores. The investigated periods include four interglacial time slices: the pre-industrial control (CTRL), mid-Holocene (6000 yr BP; hereafter referred to as \\"6 kyr\\"), last glacial inception (115 000 yr BP; hereafter \\"115 kyr\\") and Eemian (126 000 yr BP; hereafter \\"126 kyr\\"). One glacial time interval, the Last Glacial Maximum (LGM) (21 000 yr BP; hereafter \\"21 kyr\\"), was simulated as well to be a reference test for the model. Results suggest an increase in mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two-thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one-third of the increase in dust deposition. The moderate change in dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times

  17. Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

    SciTech Connect

    Sudarchikova, Natalia; Mikolajewicz, Uwe; Timmreck, C.; O'Donnell, D.; Schurgers, G.; Sein, Dmitry; Zhang, Kai

    2015-05-19

    The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide unique information about deposition of aeolian dust particles transported over long distances. These cores are a palaeoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol–climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission, atmospheric transport and precipitation, which will help to interpret palaeodata from Antarctic ice cores. The investigated periods include four interglacial time slices: the pre-industrial control (CTRL), mid-Holocene (6000 yr BP; hereafter referred to as \\"6 kyr\\"), last glacial inception (115 000 yr BP; hereafter \\"115 kyr\\") and Eemian (126 000 yr BP; hereafter \\"126 kyr\\"). One glacial time interval, the Last Glacial Maximum (LGM) (21 000 yr BP; hereafter \\"21 kyr\\"), was simulated as well to be a reference test for the model. Results suggest an increase in mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two-thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one-third of the increase in dust deposition. The moderate change in dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times higher

  18. An online mineral dust model within the global/regional NMMB: current progress and plans

    NASA Astrophysics Data System (ADS)

    Perez, C.; Haustein, K.; Janjic, Z.; Jorba, O.; Baldasano, J. M.; Black, T.; Nickovic, S.

    2008-12-01

    While mineral dust distribution and effects are important on global scales, they strongly depend on dust emissions that are occurring on small spatial and temporal scales. Indeed, the accuracy of surface wind speed used in dust models is crucial. Due to the high-order power dependency on wind friction velocity and the threshold behaviour of dust emissions, small errors in surface wind speed lead to large dust emission errors. Most global dust models use prescribed wind fields provided by major meteorological centres (e.g., NCEP and ECMWF) and their spatial resolution is currently about 1 degree x 1 degree . Such wind speeds tend to be strongly underestimated over arid and semi-arid areas and do not account for mesoscale systems responsible for a significant fraction of dust emissions regionally and globally. Other significant uncertainties in dust emissions resulting from such approaches are related to the misrepresentation of high subgrid-scale spatial heterogeneity in soil and vegetation boundary conditions, mainly in semi-arid areas. In order to significantly reduce these uncertainties, the Barcelona Supercomputing Center is currently implementing a mineral dust model coupled on-line with the new global/regional NMMB atmospheric model using the ESMF framework under development in NOAA/NCEP/EMC. The NMMB is an evolution of the operational WRF-NMME extending from meso to global scales, and including non-hydrostatic option and improved tracer advection. This model is planned to become the next-generation NCEP mesoscale model for operational weather forecasting in North America. Current implementation is based on the well established regional dust model and forecast system Eta/DREAM (http://www.bsc.es/projects/earthscience/DREAM/). First successful global simulations show the potentials of such an approach and compare well with DREAM regionally. Ongoing developments include improvements in dust size distribution representation, sedimentation, dry deposition, wet

  19. Observations of smoke and mineral dust over Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Nisantzi, Argyro; Elisavet Mamouri, Rodanthi; Hadjimitsis, Diofandos; Ansmann, Albert

    2016-04-01

    Four-year combined observations (2010-2014) with EARLINET polarization lidar and AERONET sun/sky photometer at Limassol (34.7 N, 33 E), Cyprus, Eastern Mediterranean, were used in order to study the soil dust content in lofted fire smoke plumes. This study focuses on air masses advected from Turkey as well regions further north of Black Sea during the main burning season (summer half year). Cases with strong impact of smoke events (occurring over Turkey during 1-3 days before arrival at Limassol) and observations with more background-like aerosol signatures (not influenced by Turkish fire smoke) were separated. This first systematic attempt to characterize less than 3-day-old smoke plumes in terms of particle linear depolarization ratio (PDR), measured with lidar, shown that PDR was typically 10-15% when Turkish fires contributed to the aerosol burden in the free troposphere and considerably lower with values 3-8% when fires over Turkey were absent while the air masses cross this country. High Ångström exponents of 1.4-2.2 during all these events with lofted smoke layers, occurring between 1 and 3 km height, suggest the absence of a pronounced particle coarse mode. When PDR plotted vs. travel time (spatial distance between Limassol and last fire area), PDR decreased strongly from initial values around 16-18% (1 day travel) to 4-8% after 4 days of travel caused by deposition processes. This behavior was found to be in close agreement with findings described in the literature. Biomass burning should therefore be considered as another source of free tropospheric soil dust.

  20. Predicting the mineral composition of dust aerosols - Part 1: Representing key processes

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Pérez García-Pando, C.; Miller, R. L.

    2015-10-01

    Soil dust aerosols created by wind erosion are typically assigned globally uniform physical and chemical properties within Earth system models, despite known regional variations in the mineral content of the parent soil. Mineral composition of the aerosol particles is important to their interaction with climate, including shortwave absorption and radiative forcing, nucleation of cloud droplets and ice crystals, heterogeneous formation of sulfates and nitrates, and atmospheric processing of iron into bioavailable forms that increase the productivity of marine phytoplankton. Here, aerosol mineral composition is derived by extending a method that provides the composition of a wet-sieved soil. The extension accounts for measurements showing significant differences between the mineral fractions of the wet-sieved soil and the emitted aerosol concentration. For example, some phyllosilicate aerosols are more prevalent at silt sizes, even though they are nearly absent at these diameters in a soil whose aggregates are dispersed by wet sieving. We calculate the emitted mass of each mineral with respect to size by accounting for the disintegration of soil aggregates during wet sieving. These aggregates are emitted during mobilization and fragmentation of the original undispersed soil that is subject to wind erosion. The emitted aggregates are carried far downwind from their parent soil. The soil mineral fractions used to calculate the aggregates also include larger particles that are suspended only in the vicinity of the source. We calculate the emitted size distribution of these particles using a normalized distribution derived from aerosol measurements. In addition, a method is proposed for mixing minerals with small impurities composed of iron oxides. These mixtures are important for transporting iron far from the dust source, because pure iron oxides are more dense and vulnerable to gravitational removal than most minerals comprising dust aerosols. A limited comparison to

  1. Predicting the Mineral Composition of Dust Aerosols. Part 1; Representing Key Processes

    NASA Technical Reports Server (NTRS)

    Perlwitz, J. P.; Garcia-Pando, C. Perez; Miller, R. L.

    2015-01-01

    Soil dust aerosols created by wind erosion are typically assigned globally uniform physical and chemical properties within Earth system models, despite known regional variations in the mineral content of the parent soil. Mineral composition of the aerosol particles is important to their interaction with climate, including shortwave absorption and radiative forcing, nucleation of cloud droplets and ice crystals, heterogeneous formation of sulfates and nitrates, and atmospheric processing of iron into bioavailable forms that increase the productivity of marine phytoplankton. Here, aerosol mineral composition is derived by extending a method that provides the composition of a wet-sieved soil. The extension accounts for measurements showing significant differences between the mineral fractions of the wetsieved soil and the emitted aerosol concentration. For example, some phyllosilicate aerosols are more prevalent at silt sizes, even though they are nearly absent at these diameters in a soil whose aggregates are dispersed by wet sieving. We calculate the emitted mass of each mineral with respect to size by accounting for the disintegration of soil aggregates during wet sieving. These aggregates are emitted during mobilization and fragmentation of the original undispersed soil that is subject to wind erosion. The emitted aggregates are carried far downwind from their parent soil. The soil mineral fractions used to calculate the aggregates also include larger particles that are suspended only in the vicinity of the source. We calculate the emitted size distribution of these particles using a normalized distribution derived from aerosol measurements. In addition, a method is proposed for mixing minerals with small impurities composed of iron oxides. These mixtures are important for transporting iron far from the dust source, because pure iron oxides are more dense and vulnerable to gravitational removal than most minerals comprising dust aerosols. A limited comparison to

  2. Chemistry and mineralogy of clay minerals in Asian and Saharan dusts and the implications for iron availability

    NASA Astrophysics Data System (ADS)

    Jeong, G. Y.; Achterberg, E. P.

    2014-06-01

    Mineral dust supplied to remote ocean regions stimulates phytoplankton growth through delivery of micronutrients, notably iron (Fe). Although attention is usually paid to Fe (hydr)oxides as major sources of available Fe, Fe-bearing clay minerals are typically the dominant phase in mineral dust. The mineralogy and chemistry of clay minerals in dust particles, however, are largely unknown. We conducted microscopic identification and chemical analysis of the clay minerals in Asian and Saharan dust particles. Cross-sectional slices of dust particles were prepared by focused ion beam (FIB) techniques and analyzed by transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDXS). TEM images of FIB slices revealed that clay minerals occurred as either nano-thin platelets or relatively thick plates. The nano-thin platelets included illite, smectite, illite-smectite mixed layers and their nanoscale mixtures (illite-smectite series clay minerals, ISCMs) which could not be resolved with an electron microbeam. EDXS chemical analysis of the clay mineral grains revealed that the average Fe content was 5.8% in nano-thin ISCM platelets assuming 14% H2O, while the Fe content of illite and chlorite was 2.8 and 14.8%, respectively. In addition, TEM and EDXS analyses were performed on clay mineral grains dispersed and loaded on microgrids. The average Fe content of clay mineral grains was 6.7 and 5.4% in Asian and Saharan dusts, respectively. A comparative X-ray diffraction analysis of bulk dusts showed that Saharan dust was more enriched in clay minerals than in Asian dust, while Asian dust was more enriched in chlorite. The average Fe / Si, Al / Si and Fe / Al molar ratios of the clay minerals, compared to previously reported chemistries of mineral dusts and leached solutions, indicated that dissolved Fe originated from clay minerals. Clay minerals, in particular nanocrystalline ISCMs and Fe-rich chlorite are important sources of available Fe in

  3. An evaluation of effect of airborne dust from a cotton mill on the guinea-pig ileum with reference to byssinosis.

    PubMed

    Cinkotai, F F; Franklin, D W

    1975-08-01

    The effect of airborne dust on the guinea-pig ileum was studied. Tyrode extracts of airborne dust collected freshly in the cardroom of a cotton mill, and extracts of air pollutant samples drawn on the roof of the mill and of the local town hall were all found to induce the guinea-pig ileum to contract when applied in a tissue-bath. However, the force of contraction with air pollutants was rather greater than that with the cardroom dust. Considering the variables involved, the ileum response to the cardroom dust may have been due to ordinary air pollutants which constitute a significant part of the dust. It is concluded that this pharmacological phenomenon is probably not relevant in the context of byssinosis.

  4. Atmospheric Processing of Iron-Containing Mineral Dust Aerosol: A Major Source of Bioavailable Iron to Ocean Life

    NASA Astrophysics Data System (ADS)

    Rubasinghege, G. R. S.; Hurub, O. A.

    2015-12-01

    In the present day, it has become more apparent that redox reactions involving mineral dust are of great interest, especially for Fe-containing mineral dust, as they transported and deposited into certain regions of the ocean that dissolved iron is often a limiting nutrient for ocean life. Given that heterogeneous reactions of Fe-containing mineral dust with acidic gases and their precursors, i.e. HNO3, dimethyl sulfide( DMS), lead to lower pH environments, the amount of bioavailable iron can increase as they are transported through the atmosphere. The current work focuses on chemical and photochemical processing of Fe-containing mineral dust particles in the presence of HNO3, SO2 and DMS under atmospherically relevant conditions. Here, various spectroscopic methods are combined with dissolution measurements to investigate atmospheric processing of iron containing aerosol dust, with a specific focus on mineralogy and environmental conditions, i.e. pH, relative humidity, temperature and solar flux. Ilmenite (FeTiO3) is used as one of the proxies for Fe-containing minerals that have enough complexity to mimic the mineral dust, yet simple enough to know the details of the reaction pathways. During these studies, above factors are found to play significant roles in the dissolution of iron from mineral dust aerosol. More importantly, data suggest that presence of titanium in the lattice structure of ilmenite enhances iron dissolution, at least by 3-fold in a comparison with hematite. Further, growth and activity of ocean diatoms (Cyclotella meneghiniana) are monitored in the presence of Fe-containing mineral dust under the same conditions. Here, diatoms are added to the reactors containing pre-dissolved iron from a prior 48hr reaction. Results show a high correlation between the growth of diatoms and the amount of bioavailable from iron containing minerals. The current study thus highlights these important, yet unconsidered, factors in the atmospheric processing of iron

  5. Active airborne infrared laser system for identification of surface rock and minerals

    NASA Technical Reports Server (NTRS)

    Kahle, A. B.; Shumate, M. S.; Nash, D. B.

    1984-01-01

    Emissivity and reflectivity in the thermal infrared spectral region (8-13 microns) may be used to discriminate among rocks and minerals. Although considerable success has been achieved in remote sensing classification of rock types based on emissivity measurements made with NASA's Thermal Infreared Multispectral Scanner (TIMS), classification based on reflectivity offers several advantages: much narrower bandwidths are used, higher signal to noise ratios are possible, and measurements are little affected by surface temperature. As a demonstration, an airborne CO2 laser instrument was flown along the margin of Death Valley, California. Measurements of spectral reflectance collected with this device were compared with emissivity measurements made with the TIMS. Data from either instrument provided the means for recognizing boundaries between geologic units including different rock types and fan surfaces of different ages.

  6. Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

    PubMed

    Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

    2012-09-01

    Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined. PMID:22177528

  7. Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

    PubMed

    Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

    2012-09-01

    Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from <0.001 to 2.9mg/m(3), and, in all but one case, resulted in concentrations below the current U.S. Occupational Safety and Health Administration's Permissible Exposure Limits and the American Conference of Governmental Industrial Hygienists' Threshold Limit Values. The arithmetic mean total dust concentration resulting from long-term personal samples was 0.31mg/m(3). The data presented here are the most complete set of its kind in the open literature, and are useful for understanding the potential exposures during solid catalyst handling activities at this petroleum refinery and perhaps other modern refineries during the timeframe examined.

  8. Quantifying atmospheric processing of mineral dust as a source of bioavailable phosphorus to the open oceans

    NASA Astrophysics Data System (ADS)

    Herbert, Ross; Stockdale, Anthony; Carslaw, Ken; Krom, Michael

    2016-04-01

    The transport and deposition of mineral dust is known to be the dominant source of phosphorus (P) to the surface waters of the open oceans. However, the fraction of this P that is deemed available for primary productivity remains a key uncertainty due to a limited understanding of the processes occurring during transport of the dust. Through a series of detailed laboratory experiments using desert dust and dust precursors, we show that the dissolution behaviour of P in these samples is controlled by a surface-bound labile pool, and an additional mineral pool primarily consisting of apatite. The acid dissolution of the apatite occurs rapidly and is controlled by the absolute number of H+ ions present in the solution surrounding the dust. Using these results we develop a new conceptual model that reproduces the major processes controlling P dissolution in the atmosphere. We then use a global aerosol microphysics model with a global soil database to quantify the deposition of bioavailable P to the open oceans and ice sheets. We show that, globally, the labile pool contributes 2.4 Gg P a-1 to the oceans and, from a potential pool of 11.5 Gg P a-1, the dissolved apatite pool contributes 0.24 Gg P a-1. A series of sensitivity studies identifying sources of acid in the atmosphere show that anthropogenic emissions of SO2 contribute 61% of the global mass of dissolved apatite, volcanic events contribute 11%, and DMS emissions contribute 10%. Finally, we show that the fraction of mineral dust P that is available for primary productivity varies, regionally, from <20% in the North Atlantic Ocean to >50% in the South Pacific Ocean; this explains the variability in the fraction of bioavailable P commonly observed in important oceanic regions.

  9. Chemical processing does not always impair heterogeneous ice nucleation of mineral dust particles

    NASA Astrophysics Data System (ADS)

    Sullivan, R. C.; Demott, P. J.; Prenni, A. J.; Minambres, L.; Kreidenweis, S. M.; Moehler, O.

    2010-12-01

    Mineral dust particles are the most abundant heterogeneous ice nuclei in the atmosphere. They also frequently become mixed with secondary material during atmospheric transport. The effect that such atmospheric processing has on the ice nucleation properties of dust particles remains under investigation. We have studied changes in the ice nucleation ability of various mineral dust sources after exposure to nitric acid in an aerosol flow tube, and after heterogeneous nucleation of α-pinene secondary organic aerosol (SOA) in the AIDA cloud expansion chamber. Both chemical treatments altered and homogenized the dust particles’ heterogeneous ice nucleation properties below water-saturation, but had no apparent impact on the immersion-freezing fraction well above water saturation. The fraction of particles capable of nucleating ice at fixed mixed-phase cloud temperatures between -35 and -15 °C was determined using a continuous flow diffusion chamber (CFDC) as the relative humidity with respect to water (RHw) was scanned from 75% to 110% RHw. Exposure to both nitric acid and SOA impaired essentially all ice nucleation in the deposition-regime below water saturation, while causing the onset of condensation-freezing to occur in a step-wise manner over a small range of RHw just below water saturation. We interpret this as the result of an increase in particle hygroscopicity following chemical treatment. This allows the mineral particles to absorb enough water to overcome solute freezing point depression effects and nucleate ice via condensation-freezing at a slightly smaller and narrower range of RHw than the less hygroscopic untreated dust can. Immersion-freezing above water saturation was not affected by either treatment. This is in stark contrast to earlier experiments where dust was exposed to sulfuric acid from a heated vapor source; ice nucleation was notably impaired in both the deposition and immersion-freezing regimes following sulfuric acid treatment.

  10. Quantifying atmospheric processing of mineral dust as a source of bioavailable phosphorus to the open oceans

    NASA Astrophysics Data System (ADS)

    Herbert, Ross; Stockdale, Anthony; Carslaw, Ken; Krom, Michael

    2016-04-01

    The transport and deposition of mineral dust is known to be the dominant source of phosphorus (P) to the surface waters of the open oceans. However, the fraction of this P that is deemed available for primary productivity remains a key uncertainty due to a limited understanding of the processes occurring during transport of the dust. Through a series of detailed laboratory experiments using desert dust and dust precursors, we show that the dissolution behaviour of P in these samples is controlled by a surface-bound labile pool, and an additional mineral pool primarily consisting of apatite. The acid dissolution of the apatite occurs rapidly and is controlled by the absolute number of H+ ions present in the solution surrounding the dust. Using these results we develop a new conceptual model that reproduces the major processes controlling P dissolution in the atmosphere. We then use a global aerosol microphysics model with a global soil database to quantify the deposition of bioavailable P to the open oceans and ice sheets. We show that, globally, the labile pool contributes 2.4 Gg P a‑1 to the oceans and, from a potential pool of 11.5 Gg P a‑1, the dissolved apatite pool contributes 0.24 Gg P a‑1. A series of sensitivity studies identifying sources of acid in the atmosphere show that anthropogenic emissions of SO2 contribute 61% of the global mass of dissolved apatite, volcanic events contribute 11%, and DMS emissions contribute 10%. Finally, we show that the fraction of mineral dust P that is available for primary productivity varies, regionally, from <20% in the North Atlantic Ocean to >50% in the South Pacific Ocean; this explains the variability in the fraction of bioavailable P commonly observed in important oceanic regions.

  11. Long-range transport across the Atlantic in summertime does not enhance the hygroscopicity of African mineral dust

    NASA Astrophysics Data System (ADS)

    Denjean, C.; Caquineau, S.; Desboeufs, K.; Laurent, B.; Maille, M.; Quiñones Rosado, M.; Vallejo, P.; Mayol-Bracero, O. L.; Formenti, P.

    2015-09-01

    We present the first direct evidence that the hygroscopic properties of super micron (>1 µm) African dust particles did not change despite undergoing long-range transport across the Atlantic toward the Caribbean. Concurrent measurements of chemical composition show that most of mineral dust was chemically unprocessed and externally mixed. A minor portion of mineral dust was internally mixed with sulfate and chloride (~13-24% by number) or aggregated with sea-salt particles (~3-6%). Only dust particles aggregated with sea salt showed significant hygroscopic growth above 75% relative humidity (RH), resulting in a decrease in extinction mass efficiency by up to a factor 2.2. All other dust particles did not take up significant amounts of water when exposed to up to 94% RH. These results demonstrate that the direct radiative effect of African dust in this region remained independent of RH and an external mixing state could be considered for evaluating the climate effects of dust.

  12. Role of clay minerals in the formation of atmospheric aggregates of Saharan dust

    NASA Astrophysics Data System (ADS)

    Cuadros, Javier; Diaz-Hernandez, José L.; Sanchez-Navas, Antonio; Garcia-Casco, Antonio

    2015-11-01

    Saharan dust can travel long distances in different directions across the Atlantic and Europe, sometimes in episodes of high dust concentration. In recent years it has been discovered that Saharan dust aerosols can aggregate into large, approximately spherical particles of up to 100 μm generated within raindrops that then evaporate, so that the aggregate deposition takes place most times in dry conditions. These aerosol aggregates are an interesting phenomenon resulting from the interaction of mineral aerosols and atmospheric conditions. They have been termed "iberulites" due to their discovery and description from aerosol deposits in the Iberian Peninsula. Here, these aggregates are further investigated, in particular the role of the clay minerals in the aggregation process of aerosol particles. Iberulites, and common aerosol particles for reference, were studied from the following periods or single dust events and locations: June 1998 in Tenerife, Canary Islands; June 2001 to August 2002, Granada, Spain; 13-20 August 2012, Granada; and 1-6 June 2014, Granada. Their mineralogy, chemistry and texture were analysed using X-ray diffraction, electron microprobe analysis, SEM and TEM. The mineral composition and structure of the iberulites consists of quartz, carbonate and feldspar grains surrounded by a matrix of clay minerals (illite, smectite and kaolinite) that also surrounds the entire aggregate. Minor phases, also distributed homogenously within the iberulites, are sulfates and Fe oxides. Clays are apparently more abundant in the iberulites than in the total aerosol deposit, suggesting that iberulite formation concentrates clays. Details of the structure and composition of iberulites differ from descriptions of previous samples, which indicates dependence on dust sources and atmospheric conditions, possibly including anthropic activity. Iberulites are formed by coalescence of aerosol mineral particles captured by precursor water droplets. The concentration of

  13. Mineral phases of weathered and recent electric arc furnace dust.

    PubMed

    Martins, Fernanda Machado; dos Reis Neto, José Manoel; da Cunha, Carlos Jorge

    2008-06-15

    A weathered and a recent sample of electric arc furnace dust (EAFD), generated in a southern Brazilian steel industry, were characterized by X-ray fluorescence spectroscopy (XFA), powder X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) probe and Fourier transform infrared spectroscopy (FTIR). A quantitative phase composition model, that accounts for the observed data and for the physico-chemical conditions of formation, was postulated for each material. One sample, in the form of a wet paste, was collected from the lowest part of a landfill and corresponds to a weathered material whereas the other sample was collected from the top portion of the landfill and corresponds to a recently produced material. The dominant cations present in both samples are iron, zinc and lead with minor amounts of manganese, calcium and silicon. The dominant mineralogical phases identified in both materials are Magnetite, Franklinite and Zincite. The recent sample has Laurionite whereas the weathered sample has Hydrocerussite and Hydrozincite.

  14. Predicting the mineral composition of dust aerosols - Part 1: Representing key processes

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Pérez García-Pando, C.; Miller, R. L.

    2015-02-01

    Soil dust aerosols created by wind erosion are typically assigned globally uniform physical and chemical properties within Earth system models, despite known regional variations in the mineral content of the parent soil. Mineral composition of the aerosol particles is important to their interaction with climate, including shortwave absorption and radiative forcing, nucleation of cloud droplets and ice crystals, coating by heterogeneous uptake of sulfates and nitrates, and atmospheric processing of iron into bioavailable forms that increase the productivity of marine phytoplankton. Here, aerosol mineral composition is derived by extending a method that provides the composition of a wet-sieved soil. The extension accounts for measurements showing significant differences between the mineral fractions of the wet-sieved soil and the resulting aerosol concentration. For example, some phyllosilicate aerosols are more prevalent at silt sizes, even though they are nearly absent in a soil whose aggregates are dispersed by wet sieving during analysis. We reconstruct the undispersed size distribution of the original soil that is subject to wind erosion. An empirical constraint upon the relative emission of clay and silt is applied that further differentiates the soil and aerosol mineral composition. In addition, a method is proposed for mixing minerals with small impurities composed of iron oxides. These mixtures are important for transporting iron far from the dust source, because pure iron oxides are more dense and vulnerable to gravitational removal than most minerals comprising dust aerosols. A limited comparison to measurements from North Africa shows that the extension brings the model into better agreement, consistent with a more extensive comparison to global observations as well as measurements of elemental composition downwind of the Sahara, as described in companion articles.

  15. Modeling the global emission, transport and deposition of trace elements associated with mineral dust

    DOE PAGES

    Zhang, Y.; Mahowald, N.; Scanza, R. A.; Journet, E.; Desboeufs, K.; Albani, S.; Kok, J. F.; Zhuang, G.; Chen, Y.; Cohen, D. D.; et al

    2015-10-12

    Trace element deposition from desert dust has important impacts on ocean primary productivity, the quantification of which could be useful in determining the magnitude and sign of the biogeochemical feedback on radiative forcing. However, the impact of elemental deposition to remote ocean regions is not well understood and is not currently included in global climate models. In this study, emission inventories for eight elements primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si are determined based on a global mineral data set and a soil data set. The resulting elemental fractions are used to drive themore » desert dust model in the Community Earth System Model (CESM) in order to simulate the elemental concentrations of atmospheric dust. Spatial variability of mineral dust elemental fractions is evident on a global scale, particularly for Ca. Simulations of global variations in the Ca / Al ratio, which typically range from around 0.1 to 5.0 in soils, are consistent with observations, suggesting that this ratio is a good signature for dust source regions. The simulated variable fractions of chemical elements are sufficiently different; estimates of deposition should include elemental variations, especially for Ca, Al and Fe. The model results have been evaluated with observations of elemental aerosol concentrations from desert regions and dust events in non-dust regions, providing insights into uncertainties in the modeling approach. The ratios between modeled and observed elemental fractions range from 0.7 to 1.6, except for Mg and Mn (3.4 and 3.5, respectively). Using the soil database improves the correspondence of the spatial heterogeneity in the modeling of several elements (Ca, Al and Fe) compared to observations. Total and soluble dust element fluxes to different ocean basins and ice sheet regions have been estimated, based on the model results. The annual inputs of soluble Mg, P, Ca, Mn, Fe and K associated with dust using the mineral data set are

  16. Modeling the global emission, transport and deposition of trace elements associated with mineral dust

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Mahowald, N.; Scanza, R. A.; Journet, E.; Desboeufs, K.; Albani, S.; Kok, J. F.; Zhuang, G.; Chen, Y.; Cohen, D. D.; Paytan, A.; Patey, M. D.; Achterberg, E. P.; Engelbrecht, J. P.; Fomba, K. W.

    2015-10-01

    Trace element deposition from desert dust has important impacts on ocean primary productivity, the quantification of which could be useful in determining the magnitude and sign of the biogeochemical feedback on radiative forcing. However, the impact of elemental deposition to remote ocean regions is not well understood and is not currently included in global climate models. In this study, emission inventories for eight elements primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si are determined based on a global mineral data set and a soil data set. The resulting elemental fractions are used to drive the desert dust model in the Community Earth System Model (CESM) in order to simulate the elemental concentrations of atmospheric dust. Spatial variability of mineral dust elemental fractions is evident on a global scale, particularly for Ca. Simulations of global variations in the Ca / Al ratio, which typically range from around 0.1 to 5.0 in soils, are consistent with observations, suggesting that this ratio is a good signature for dust source regions. The simulated variable fractions of chemical elements are sufficiently different; estimates of deposition should include elemental variations, especially for Ca, Al and Fe. The model results have been evaluated with observations of elemental aerosol concentrations from desert regions and dust events in non-dust regions, providing insights into uncertainties in the modeling approach. The ratios between modeled and observed elemental fractions range from 0.7 to 1.6, except for Mg and Mn (3.4 and 3.5, respectively). Using the soil database improves the correspondence of the spatial heterogeneity in the modeling of several elements (Ca, Al and Fe) compared to observations. Total and soluble dust element fluxes to different ocean basins and ice sheet regions have been estimated, based on the model results. The annual inputs of soluble Mg, P, Ca, Mn, Fe and K associated with dust using the mineral data set are 0.30 Tg

  17. Magnetic Properties of Iron Oxide Minerals in Atmospheric Dust and Source Sediments from Western US

    NASA Astrophysics Data System (ADS)

    Moskowitz, B. M.; Yauk, K.; Till, J. L.; Berquo, T. S.; Banerjee, S. K.; Reynolds, R. L.; Goldstein, H. L.

    2011-12-01

    Atmospheric dust contains iron oxide minerals that can play important roles in various physical and biological processes affecting atmospheric and surface temperatures, marine phytoplankton productivity, and human health. Iron oxide minerals in dust deposited on mountain snow cover are especially important because these minerals absorb solar and IR radiation leading to changes in albedo and affecting the timing and rate of spring and summer snowpack melting. As part of an ongoing project to study physical and chemical properties of dust from sources to sinks in the western US, we will describe one approach to characterize iron oxide mineralogy using magnetic property measurements and Mossbauer spectroscopy. Magnetic property measurements over a wide range of temperatures (2-300 K) and magnetic fields (0-5 T) are particularly sensitive to composition, particle size (from nanometer to micrometer), and concentration of iron oxide and oxyhydroxide minerals. The high sensitivity of magnetic measurements to target minerals allows the measurement of bulk samples preventing any aliasing of composition or grain size resulting from attempts at prior magnetic separation. In addition, different magnetic measurement protocols can isolate different particle-size assemblages and different compositions in multicomponent mixtures and help to identify dust-source areas. These techniques have been applied to dust deposited on snow (DOS) cover of the San Juan Mountains, Colorado (collected 2005-2010) and Wasatch Mountains, Utah (collected 2010) and possible dust-source sediments from the North American Great Basin and Colorado Plateau deserts. Results show that all samples contain a high coercivity phase consistent with hematite and/or goethite as the dominate ferric oxide mineral plus minor amounts of magnetite (<0.5 wt%). The presence of magnetite was determined from the detection of the characteristic Verwey transition (T=121 K) on low-temperature (< 300 K) remanence and

  18. Chemistry and mineralogy of clay minerals in Asian and Saharan dusts and the implications for iron supply to the oceans

    NASA Astrophysics Data System (ADS)

    Jeong, G. Y.; Achterberg, E. P.

    2014-11-01

    Mineral dust supplied to remote ocean regions stimulates phytoplankton growth through delivery of micronutrients, notably iron (Fe). Although attention is usually paid to Fe (hydr)oxides as major sources of available Fe, Fe-bearing clay minerals are typically the dominant phase in mineral dust. The mineralogy and chemistry of clay minerals in dust particles, however, are largely unknown. We conducted microscopic identification and chemical analysis of the clay minerals in Asian and Saharan dust particles. Cross-sectional slices of dust particles were prepared by focused ion beam (FIB) techniques and analyzed by transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDXS). TEM images of FIB slices revealed that clay minerals occurred as either nano-thin platelets or relatively thick plates. Chemical compositions and lattice fringes of the nano-thin platelets suggested that they included illite, smectite, illite-smectite mixed layers, and their nanoscale mixtures (illite-smectite series clay minerals, ISCMs) which could not be resolved with an electron microbeam. EDXS chemical analysis of the clay mineral grains revealed that the average Fe content was 5.8% in nano-thin ISCM platelets assuming 14% H2O, while the Fe content of illite and chlorite was 2.8 and 14.8%, respectively. In addition, TEM and EDXS analyses were performed on clay mineral grains dispersed and loaded on micro-grids. The average Fe content of clay mineral grains was 6.7 and 5.4% in Asian and Saharan dusts, respectively. A comparative X-ray diffraction analysis of bulk dusts showed that Saharan dust was more enriched in clay minerals than Asian dust, while Asian dust was more enriched in chlorite. Clay minerals, in particular nanocrystalline ISCMs and Fe-rich chlorite, are probably important sources of Fe to remote marine ecosystems. Further detailed analyses of the mineralogy and chemistry of clay minerals in global mineral dusts are required to evaluate the

  19. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Losno, Rémi; Bon Nguyen, Elisabeth; Roullet, Pierre; Sauvage, Stéphane; Chevaillier, Servanne; Coddeville, Patrice; Ouboulmane, Noura; di Sarra, Alcide Giorgio; Tovar-Sánchez, Antonio; Sferlazzo, Damiano; Massanet, Ana; Triquet, Sylvain; Morales Baquero, Rafael; Fornier, Michel; Coursier, Cyril; Desboeufs, Karine; Dulac, François; Bergametti, Gilles

    2016-07-01

    provenance, transport and deposition processes (i.e. wet vs. dry) of dust are different and specific for the different deposition sites in the Mediterranean studied area. The results tend to indicate that wet deposition is the main form of deposition for mineral dust in the western Mediterranean basin, but the contribution of dry deposition (in the sense that no precipitation was detected at the surface) is far from being negligible, and contributes 10 to 46 % to the major dust deposition events, depending on the sampling site.

  20. How important are atmospheric depressions and mobile cyclones for emitting mineral dust aerosol in North Africa?

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Schepanski, K.; Knippertz, P.; Heinold, B.; Tegen, I.

    2014-09-01

    This study presents the first quantitative estimate of the mineral dust emission associated with atmospheric depressions and mobile cyclones in North Africa. Atmospheric depressions are automatically tracked at 925 hPa based on ERA-Interim data from the European Centre for Medium-Range Weather Forecasts for 1989-2008. A set of filter criteria is applied to identify mobile cyclones, i.e. migrating and long-lived cyclones. The shorter term cyclone is used as a synonym for mobile cyclones. Dust emission is calculated with a dust emission model driven by 10 m winds and soil moisture from ERA-Interim. Emission peaks during winter and spring with spatial averages of 250-380 g m-2 per month. Comparison of the dust source activation frequency from the model against SEVIRI satellite observation shows a good agreement in the Bodélé Depression but differences in the north and west of North Africa. Depressions are abundant, particularly in summer when the Saharan heat low is situated over West Africa and during spring in the lee of the Atlas Mountains. Up to 90% (55% annually and spatially averaged) of dust emission occurs within 10 degrees of these depressions, with embedded mechanisms such as nocturnal low-level jets playing a role. Cyclones are rarer and occur primarily north of 20° N in spring in agreement with previous studies and over summertime West Africa consistent with near-surface signatures of African Easterly Waves. Dust emission within 10 degrees of cyclones peaks over Libya with up to 25% in spring. Despite the overall small contribution of 4% annually and spatially averaged, cyclones coincide with particularly intense dust emission events exceeding the climatological mean by a factor of four to eight. Soil moisture weakens dust emission during cyclone passage by about 10%.

  1. Enrichment of Mineral Dust Storm Particles with Sea Salt Elements - Using bulk and Single Particle Analyses

    NASA Astrophysics Data System (ADS)

    Mamane, Y.; Perrino, C.; Yossef, O.

    2009-12-01

    Mineral aerosol emitted from African and Asian deserts plays an important role in the atmosphere. During their long-range transport, the physical and chemical properties of mineral dust particles change due to heterogeneous reactions with trace gases, coagulation with other particles, and in-cloud processing. These processes affect the optical and hygroscopic properties of dust particles, and in general influencing the physics and chemistry of the atmosphere. Four African and Arabian dust storm episodes affecting the East Mediterranean Coast in the spring of 2006 have been characterized, to determine if atmospheric natural dust particles are enriched with sea salt and anthropogenic pollution. Particle samplers included PM10 and manual dichotomous sampler that collected fine and coarse particles. Three sets of filters were used: Teflon filters for gravimetric, elemental and ionic analyses; Pre-fired Quartz-fiber filters for elemental and organic carbon; and Nuclepore filters for scanning electron microscopy analysis. Computer-controlled scanning electron microscopy (Philips XL 30 ESEM) was used to analyze single particle, for morphology, size and chemistry of selected filter samples. A detailed chemical and microscopical characterization has been performed for the particles collected during dust event days and during clear days. The Saharan and Arabian air masses increased significantly the daily mass concentrations of the coarse and the fine particle fractions. Carbonates, mostly as soil calcites mixed with dolomites, and silicates are the major components of the coarse fraction, followed by sea salt particles. In addition, the levels of anthropogenic heavy metals and sea salt elements registered during the dust episode were considerably higher than levels recorded during clear days. Sea salt elements contain Na and Cl, and smaller amounts of Mg, K, S and Br. Cl ranges from 300 to 5500 ng/m3 and Na from 100 to almost 2400 ng/m3. The Cl to Na ratio on dusty days in

  2. Medical Geology in the Middle East: Potential Health Risks from Mineralized Dust Exposure

    NASA Astrophysics Data System (ADS)

    Lyles, M. B.; Fredrickson, H. L.; Bednar, A. J.; Fannin, H. B.; Griffin, D. W.; Sobecki, T. M.

    2012-04-01

    In the Middle East, dust and sand storms are a persistent problem delivering significant amounts of mineralized particulates via inhalation into the mouth, nasal pharynx, and lungs. The health risks of this dust inhalation are presently being studied but accurate characterization as to the potential health effects is still lacking. Experiments were designed to study the chemical composition, mineral content, and microbial flora of Kuwaiti and Iraqi dust particles for the potential to cause adverse human health effects both acute and chronic. Multiple site samples were collected and chemical and physical characterization including particle size distribution and inorganic analysis was conducted, followed by analysis and identification of biologic flora to include bacteria, fungi and viruses. Additionally, PM10 exposure data was collected hourly over a 12 day period (>10,000 ug/m3). Data indicates that the mineralized dust is composed of calcium carbonate and magnesium sulfate coating over a precipitated matrix of metallic silicate nanocrystals of various forms containing a variety of trace and heavy metals constituting ~3 % of the particles by weight. This includes ~ 1% by weight bioaccessible aluminum and reactive iron with the remaining 1% a mixture of bioaccessible trace and heavy metals. Microbial analysis reveals a significant biodiversity of bacteria of which ~25 % are known pathogens. Of the microbes identified, several have hemolytic properties and most have significant antibiotic resistance. Viral analysis indicates a tremendous amount of virons with a large percent of RNA viruses. The level of total suspended particle mass at PM10 constitutes an excessive exposure micro-particulates including PM 2.5 (~1,0000 ug/m3). Reported data on cell culture and animal studies have indicated a high level of toxicity to these dust particles. Taken together, these data suggest that at the level of dust exposure commonly found in the Middle East (i.e., Iraq, Kuwait, and

  3. Characterization and Acid-Mobilization Study of Iron-Containing Mineral Dust Source Materials

    SciTech Connect

    Cwiertny, David M.; Baltrusaitis, Jonas; Hunter, Gordon J.; Laskin, Alexander; Scherer, Michelle; Grassian, Vicki H.

    2008-03-04

    Processes that solubilize the iron in mineral dust aerosols may increase the amount of iron supplied to ocean surface waters, and thereby stimulate phytoplankton productivity. It was recently proposed that mixing of mineral dusts with SO2 and HNO3 produces extremely acidic environments that favor the formation of bioavailable Fe(II). Here, four authentic mineral dust source materials (Saudi Beach sand (SB), Inland Saudi sand (IS), Saharan Sand (SS) and China Loess (CL)) and one commercial reference material (Arizona Test Dust (AZTD)) were spectroscopically characterized, and their dissolution at pH 1 was examined in aqueous batch systems. Spectroscopic analyses indicated that the bulk and near-surface region of all samples possessed similar elemental compositions and that iron was unevenly distributed among dust 10 particles. Mössbauer spectroscopy revealed Fe(III) in all samples, although SB, CL and AZTD also contained appreciable Fe(II). Both Fe(II) and Fe(III) were primarily substituted into aluminosilicates, although CL, AZTD and IS also contained Fe(III) oxides. Total iron solubility (defined as the summed concentration of dissolved Fe(II) and Fe(III) measured after 24 h) ranged 14 between 4-12% of the source materials’ iron content, but did not scale with either the surface area or the iron content of the samples. This suggests that other factors such as iron speciation and mineralogy may play a key role in iron solubility. Also, the elevated nitrate concentrations encountered from nitric acid at pH 1 suppressed dissolution of Fe(II) from AZTD, CL and SB particles, which we propose results from the surface-mediated, non-photochemical reduction of nitrate by Fe(II).

  4. Discovery of Brownleeite: a New Manganese Silicide Mineral in an Interplanetary Dust Particle

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.; Nakamura-Messenger, Keiko; Clemett, Simon J.; Messenger, Scott; Jones, John H.; Palma, Russell L.; Pepin, Robert O.; Klock, Wolfgang; Zolensky, Michael E.; Tatsuoka, Hirokazu

    2011-01-01

    The Earth accretes approximately 40,000 tons of cosmic dust annually, originating mainly from the disintegration of comets and collisions among asteroids. This cosmic dust, also known as interplanetary dust particles (IDPs), is a subject of intense interest since it is made of the original building blocks of our Solar System. Although the specific parent bodies of IDPs are unknown, the anhydrous chondritic-porous IDPs (CP-IDPs) subset has been potentially linked to a cometary source. The CP-IDPs are extremely primitive materials based on their unequilibrated mineralogy, C-rich chemistry, and anomalous isotopic signatures. In particular, some CP-IDPs escaped the thermal, aqueous and impact shock processing that has modified or destroyed the original mineralogy of meteorites. Thus, the CP-IDPs represent some of the most primitive solar system materials available for laboratory study. Most CP-IDPs are comprised of minerals that are common on Earth. However, in the course of an examination of one of the CP-IDPs, we encountered three sub-micrometer sized grains of manganese silicide (MnSi), a phase that has heretofore not been found in nature. In the seminar, we would like to focus on IDP studies and this manganese silicide phase that has been approved as the first new mineral identified from a comet by the International Mineralogical Association (IMA) in 2008. The mineral is named in honour of Donald E. Brownlee, an American astronomer and a founder of the field of cosmic dust research who is the principal investigator of the NASA Stardust Mission that collected dust samples from Comet 81P/Wild-2 and returned them to Earth. Much of our current view and understanding of the early solar system would not exist without the pioneering work of professor Don Brownlee in the study of IDPs.

  5. Clay minerals in primitive meteorites and interplanetary dust 2. Smectites and micas

    NASA Technical Reports Server (NTRS)

    Keller, L. P.; Zolensky, M. E.

    1991-01-01

    The classification is briefly summarized of stony meteorites and cosmic dust, and the mineralogy and chemistry is described of serpentine group minerals. The occurrence of smectites and micas in extraterrestrial materials is examined. The characterization of fine grained minerals in meteorites and IDPs relies heavily on electron beam instruments, especially the transmission electron microscope (TEM). Typically, phyllosilicates are identified by a combination of high resolution imaging of basal spacings, electron diffraction, and chemical analysis. Smectites can be difficult to differentiate from micas because the smectites lose their interlayer water and the interlayer partly collapse in the high vacuum of the TEM.

  6. Local geological dust in the area of Rome (Italy): linking mineral composition, size distribution and optical properties to radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Pietrodangelo, Adriana; Salzano, Roberto; Bassani, Cristiana; Pareti, Salvatore; Perrino, Cinzia

    2015-04-01

    Airborne mineral dust plays a key role in the energy balance of the Earth - atmosphere coupled system. The microphysical and optical properties of dust drive the direct radiative effects and are in turn influenced by the dust mineralogical composition. The latter varies largely, depending on the geology of the source region. Knowledge gaps still exist about relationships between the scattering and absorption of solar and terrestrial radiation by mineral dust and its mineralogical, size distribution and particle morphology features; this also affects the reliability of radiative transfer (RT) modelling estimates (Hansell et al., 2011). In this study, these relationships were investigated focusing on the crustal suspended PM10 dust, sourced from outcropping rocks of the local geological domains around Rome (Latium, Italy). The mineral composition variability of the Latium rocks ranges from the silicate-dominated (volcanics domain) to the calcite-dominated (travertine), through lithological materials composed in different proportions by silicates, silica and calcite, mainly (limestone series, siliciclastic series) (Cosentino et al., 2009). This peculiarity of the Latium region was thus exploited to investigate the behavior of the size distribution, optical properties and radiative transfer at BOA (Bottom Of Atmosphere) of the suspended dust PM10 fraction with the variability of mineral composition. Elemental source profiles of the same dust samples were previously determined (Pietrodangelo et al., 2013). A multi-faceted analysis was performed, and outcomes from the following approaches were merged: individual-particle scanning electron microscopy combined with X-ray energy-dispersive microanalysis (SEM XEDS), bulk mineralogical analysis by X-ray diffraction (XRD), size distribution fit of the individual-particle data set and modelling of the dust optical and radiative properties. To this aim, the 6SV atmospheric radiative transfer code (Kotchenova et al., 2008

  7. Geltape method for measurement of work related surface contamination with cobalt containing dust: correlation between surface contamination and airborne exposure.

    PubMed Central

    Poulsen, O M; Olsen, E; Christensen, J M; Vinzent, P; Petersen, O H

    1995-01-01

    OBJECTIVES--The geltape method is a new method for optical measurement of total amount of dust on surfaces. The objectives were to study the potential applicability of this method to measurements of work related cobalt exposure during painting of plates with cobalt dye. METHODS--Consecutive series of work related geltape prints were taken from surfaces inside and outside the ventilation cabins of two plate painters during two full working days. The amount of dust picked up by the geltapes was measured optically with a field monitor. Also, personal air samples were collected on filters at the different work processes. In the laboratory the contents of cobalt on the geltape prints and the filters were measured with inductive coupled plasma atomic emission spectroscopy. RESULTS--The key results were: (a) when the geltape prints were taken from surfaces inside the cabins the optically measured area of the geltapes covered with total dust (area (%)) correlated well with the chemically measured amount of cobalt present on the geltapes. Linear correlation coefficient (R2) was 0.91 for geltape prints taken on the floor and 0.94 for prints taken on the ceiling; (b) the cumulative airborne cobalt exposure, calculated from data on work related exposure by personal sampling, correlated with the area (%) of geltape prints taken from the ceiling of the cabin (R2 = 0.98); (c) the geltape method could be used to distinguish both between work processes with different levels of cobalt exposure, and between plate painters subjected to significant differences in airborne cobalt exposure. CONCLUSION--The geltape method could produce measures of the work related exposures as well as whole day exposure for cobalt. The geltape results correlated with measurements of personal airborne cobalt exposure. In this industry the profile of exposure is well-defined in time, and it seems reasonable to apply this fast and low cost method in routine exposure surveillance to obtain a more detailed

  8. An integrated modeling study on the effects of mineral dust and sea salt particles on clouds and precipitation

    NASA Astrophysics Data System (ADS)

    Solomos, S.; Kallos, G.; Kushta, J.; Astitha, M.; Tremback, C.; Nenes, A.; Levin, Z.

    2010-10-01

    The amount of airborne particles that will nucleate and form cloud droplets under specific atmospheric conditions, depends on their number concentration, size distribution and chemical composition. Aerosol is affected by primary particle emissions, gas-phase precursors, their transformation and interaction with atmospheric constituents, clouds and dynamics. A comprehensive assessment of these interactions requires an integrated approach; most studies however decouple aerosol processes from cloud and atmospheric dynamics and cannot account for all the feedbacks involved in aerosol-cloud-climate interactions. This study addresses aerosol-cloud-climate interactions with the Integrated Community Limited Area Modeling System (ICLAMS) that includes online parameterization of the physical and chemical processes between air quality and meteorology. ICLAMS is an extended version of the Regional Atmospheric Modeling System (RAMS) and it has been designed for coupled air quality - meteorology studies. Model sensitivity tests for a single-cloud study as well as for a case study over the Eastern Mediterranean illustrate the importance of aerosol properties in cloud formation and precipitation. Mineral dust particles are often coated with soluble material such as sea-salt, thus exhibiting increased CCN efficiency. Increasing the percentage of salt-coated dust particles by 15% in the model resulted in more vigorous convection and more intense updrafts. The clouds that were formed extended about 3 km higher and the initiation of precipitation was delayed by one hour. Including on-line parameterization of the aerosol effects improved the model bias for the twenty-four hour accumulated precipitation by 7%. However, the spatial distribution and the amounts of precipitation varied greatly between the different aerosol scenarios. These results indicate the large portion of uncertainty that remains unresolved and the need for more accurate description of aerosol feedbacks in atmospheric

  9. Relationship between Rock Varnish and Adjacent Mineral Dust Compositions Using Microanalytical Techniques

    NASA Astrophysics Data System (ADS)

    Macholdt, D.; Jochum, K. P.; Otter, L.; Stoll, B.; Weis, U.; Pöhlker, C.; Müller, M.; Kappl, M.; Weber, B.; Kilcoyne, A. L. D.; Weigand, M.; Al-Amri, A. M.; Andreae, M. O.

    2015-12-01

    Rock varnishes are up to 250 μm thick, Mn- and Fe-rich, dark black to brownish-orange lustrous rock coatings. Water and aeolian dust (60-70%), in combination with biological oxidation or inorganic precipitation processes, or even a combination of both, induce varnish growth rates of a few μm per 1000 a, indicating that element enrichment and aging processes are of major importance for the varnish formation. A combination of 200 nm-fs laser- and 213 nm-ns laser ablation- inductively coupled plasma-mass spectrometry (LA-ICP-MS), focused ion beam (FIB) slicing, and scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS) was chosen for high-spatial-resolution analyses. The aim was to identify provenance, chemistry, and dynamics of the varnishes, and their formation over the millennia. To this end, mineral dust and adjacent varnishes were sampled in six arid to semi-arid deserts, in Israel, South Africa, California, and Saudi Arabia. Dust minerals incorporated in the varnishes were examined by STXM-NEXAFS spectroscopic and element mapping at the nm scale. Varnishes from different locations can be distinguished by element ratio plots of Pb/Ni vs. Mn/Ba. A comparison of dust element ratios of particles <50 μm to ratios of adjacent varnishes reveals much lower values for dust. However, the factors between the element ratios of dust and of varnish are similar for four of six regions (Mn/Ba: 6 ± 2; Pb/Ni: 4 ± 3). Two of the six regions diverge, which are South African (Mn/Ba: 20, Pb/Ni: 0.5) and Californian (Anza Borrego Desert: Mn/Ba: 4.5; Pb/Ni: 16.5) varnishes.The results indicate that the enrichment and degradation processes might be similar for most locations, and that Mn and Pb are preferably incorporated and immobilized in most varnishes compared to Ba and Ni. The Pb/Ni ratios of the South African varnishes are indicators for either a preferred incorporation of Ni compared to Pb from available dust, and

  10. Temperature and emissivity separation and mineral mapping based on airborne TASI hyperspectral thermal infrared data

    NASA Astrophysics Data System (ADS)

    Cui, Jing; Yan, Bokun; Dong, Xinfeng; Zhang, Shimin; Zhang, Jingfa; Tian, Feng; Wang, Runsheng

    2015-08-01

    Thermal infrared remote sensing (8-12 μm) (TIR) has great potential for geologic remote sensing studies. TIR has been successfully used for terrestrial and planetary geologic studies to map surface materials. However, the complexity of the physics and the lack of hyperspectral data make the studies under-investigated. A new generation of commercial hyperspectral infrared sensors, known as Thermal Airborne Spectrographic Imager (TASI), was used for image analysis and mineral mapping in this study. In this paper, a combined method integrating normalized emissivity method (NEM), ratio algorithm (RATIO) and maximum-minimum apparent emissivity difference (MMD), being applied in multispectral data, has been modified and used to determine whether this method is suitable for retrieving emissivity from TASI hyperspectral data. MODTRAN 4 has been used for the atmospheric correction. The retrieved emissivity spectra matched well with the field measured spectra except for bands 1, 2, and 32. Quartz, calcite, diopside/hedenbergite, hornblende and microcline have been mapped by the emissivity image. Mineral mapping results agree with the dominant minerals identified by laboratory X-ray powder diffraction and spectroscopic analyses of field samples. Both of the results indicated that the atmospheric correction method and the combined temperature-emissivitiy method are suitable for TASI image. Carbonate skarnization was first found in the study area by the spatial extent of diopside. Chemical analyses of the skarn samples determined that the Au content was 0.32-1.74 g/t, with an average Au content of 0.73 g/t. This information provides an important resource for prospecting for skarn type gold deposits. It is also suggested that TASI is suitable for prospect and deposit scale exploration.

  11. Dust exposure and respiratory disease in U. S. coal miners. Doctoral thesis

    SciTech Connect

    Seixas, N.S.

    1990-01-01

    The investigation was carried out by considering the exposure response relationship in a group of 1270 miners whose exposure began in or after 1970 when the regulations took effect. Over a 15 year period the results of the study indicated statistically significant positive associations of cumulative exposure with decrements in forced expiratory volume in 1 second (FEV1), FEV1/forced vital capacity (FVC), and symptoms of chronic bronchitis, breathlessness and wheeze with shortness of breath. As a result of the act, these miners were exposed to dust concentrations generally less than 2.0mg/m3. The study suggested that miners entering exposure for the first time in 1970 or later, experienced a rapid initial loss of pulmonary function in relation to their cumulative exposure to dust. The losses were observed in both FVC and FEV1 suggesting that the effect was primarily on lung volumes. Over the following 12 years there was little additional exposure related loss. The study concluded that the regulations have not been completely successful in preventing respiratory effects from exposure to coal mine dust.

  12. Saharan dust long-range transport across the Atlantic studied by an airborne Doppler wind lidar and the MACC model

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Benedetti, Angela; Weinzierl, Bernadett

    2016-09-01

    A huge amount of dust is transported every year from north Africa into the Caribbean region. This paper presents an investigation of this long-range transport process based on airborne Doppler wind lidar (DWL) measurements conducted during the SALTRACE campaign (June-July 2013), as well as an evaluation of the ability of the MACC (Monitoring Atmospheric Composition and Climate) global aerosol model to reproduce it and its associated features. Although both the modeled winds from MACC and the measurements from the DWL show a generally good agreement, some differences, particularly in the African easterly jet (AEJ) intensity, were noted. The observed differences between modeled and measured wind jet speeds are between 5 and 10 m s-1. The vertical aerosol distribution within the Saharan dust plume and the marine boundary layer is investigated during the June-July 2013 period based on the MACC aerosol model results and the CALIOP satellite lidar measurements. While the modeled Saharan dust plume extent shows a good agreement with the measurements, a systematic underestimation of the marine boundary layer extinction is observed. Additionally, three selected case studies covering different aspects of the Saharan dust long-range transport along the west African coast, over the North Atlantic Ocean and the Caribbean are presented. For the first time, DWL measurements are used to investigate the Saharan dust long-range transport. Simultaneous wind and backscatter measurements from the DWL are used, in combination with the MACC model, to analyze different features associated with the long-range transport, including an African easterly wave trough, the AEJ and the intertropical convergence zone.

  13. Microscopy and Spectroscopy Techniques to Guide Parameters for Modeling Mineral Dust Aerosol Particles

    NASA Astrophysics Data System (ADS)

    Veghte, D. P.; Moore, J. E.; Jensen, L.; Freedman, M. A.

    2013-12-01

    Mineral dust aerosol particles are the second largest emission by mass into the atmosphere and contribute to the largest uncertainty in radiative forcing. Due to the variation in size, composition, and shape, caused by physical and chemical processing, uncertainty exists as to whether mineral dust causes a net warming or cooling effect. We have used Cavity Ring-Down Aerosol Extinction Spectroscopy (CRD-AES), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) to measure extinction cross sections and morphologies of size-selected, non-absorbing and absorbing mineral dust aerosol particles. We have found that microscopy is essential for characterizing the polydispersity of the size selection of non-spherical particles. Through the combined use of CRD-AES, microscopy, and computation (Mie theory and Discreet Dipole Approximation), we have determined the effect of shape on the optical properties of additional species including clay minerals, quartz, and hematite in the sub-micron regime. Our results have shown that calcite can be treated as polydisperse spheres while quartz and hematite need additional modeling parameters to account for their irregularity. Size selection of clay minerals cannot be performed due to their irregular shape, but microscopy techniques can be used to better quantify the particle aspect ratio. Our results demonstrate a new method that can be used to extend cavity ring-down spectroscopy for the measurement of the optical properties of non-spherical particles. This characterization will lead to better aerosol extinction parameters for modeling aerosol optical properties in climate models and satellite retrieval algorithms.

  14. Contributions of dust exposure and cigarette smoking to emphysema severity in coal miners in the United States

    SciTech Connect

    Kuempel, E.D.; Wheeler, M.W.; Smith, R.J.; Vallyathan, V.; Green, F.H.Y.

    2009-08-15

    Previous studies have shown associations between dust exposure or lung burden and emphysema in coal miners, although the separate contributions of various predictors have not been clearly demonstrated. The objective was to quantitatively evaluate the relationship between cumulative exposure to respirable coal mine dust, cigarette smoking, and other factors on emphysema severity. The study group included 722 autopsied coal miners and nonminers in the United States. Data on work history, smoking, race, and age at death were obtained from medical records and questionnaire completed by next-of-kin. Emphysema was classified and graded using a standardized schema. Job-specific mean concentrations of respirable coal mine dust were matched with work histories to estimate cumulative exposure. Relationships between various metrics of dust exposure (including cumulative exposure and lung dust burden) and emphysema severity were investigated in weighted least squares regression models. Emphysema severity was significantly elevated in coal miners compared with nonminers among ever- and never-smokers (P < 0.0001). Cumulative exposure to respirable coal mine dust or coal dust retained in the lungs were significant predictors of emphysema severity (P < 0.0001) after accounting for cigarette smoking, age at death, and race. The contributions of coal mine dust exposure and cigarette smoking were similar in predicting emphysema severity averaged over this cohort. Coal dust exposure, cigarette smoking, age, and race are significant and additive predictors of emphysema severity in this study.

  15. Respirable coal dust exposure and respiratory symptoms in South-African coal miners: A comparison of current and ex-miners

    SciTech Connect

    Naidoo, R.N.; Robins, T.G.; Seixas, N.; Lalloo, U.G.; Becklake, M.

    2006-06-15

    Dose-response associations between respirable dust exposure and respiratory symptoms and between symptoms and spirometry outcomes among currently employed and formerly employed South-African coal miners were investigated. Work histories, interviews, and spirometry and cumulative exposure were assessed among 684 current and 212 ex-miners. Results: Lower prevalences of symptoms were found among employed compared with ex-miners. Associations with increasing exposure for symptoms of phlegm and past history of tuberculosis were observed, whereas other symptom prevalences were higher in the higher exposure categories. Symptomatic ex-miners exhibited lower lung-function compared to the nonsymptomatic. Compared with published data, symptoms rates were low in current miners but high in ex-miners. Although explanations could include the low prevalence of smoking and/or reporting/selection bias, a 'Survivor' and/or a 'hire' effect is more likely, resulting in an underestimation of the dust-related effect.

  16. Reducing Coal Dust With Water Jets

    NASA Technical Reports Server (NTRS)

    Gangal, M. D.; Lewis, E. V.

    1985-01-01

    Jets also cool and clean cutting equipment. Modular pick-and-bucket miner suffers from disadvantage: Creates large quantities of potentially explosive coal dust. Dust clogs drive chain and other parts and must be removed by hand. Picks and bucket lips become overheated by friction and be resharpened or replaced frequently. Addition of oscillating and rotating water jets to pick-and-bucket machine keeps down dust, cools cutting edges, and flushes machine. Rotating jets wash dust away from drive chain. Oscillating jets cool cutting surfaces. Both types of jet wet airborne coal dust; it precipitates.

  17. Comparison of optical and microphysical properties of pure Saharan mineral dust observed with AERONET Sun photometer, Raman lidar, and in situ instruments during SAMUM 2006

    NASA Astrophysics Data System (ADS)

    Müller, D.; Lee, K.-H.; Gasteiger, J.; Tesche, M.; Weinzierl, B.; Kandler, K.; Müller, T.; Toledano, C.; Otto, S.; Althausen, D.; Ansmann, A.

    2012-04-01

    The Saharan Mineral Dust Experiment (SAMUM) 2006, Morocco, aimed at the characterization of optical, physical, and radiative properties of Saharan dust. AERONET Sun photometer, several lidars (Raman and high-spectral-resolution instruments), and airborne and ground-based in situ instruments provided us with a comprehensive set of data on particle-shape dependent and particle-shape independent dust properties. We compare 4 measurement days in detail, and we carry out a statistical analysis for some of the inferred data products for the complete measurement period. Particle size distributions and complex refractive indices inferred from the Sun photometer observations and measured in situ aboard a research aircraft show systematic differences. We find differences in the wavelength-dependence of single-scattering albedo, compared to light-scattering computations that use data from SOAP (spectral optical absorption photometer). AERONET data products of particle size distribution, complex refractive index, and axis ratios were used to compute particle extinction-to-backscatter (lidar) ratios and linear particle depolarization ratios. We find differences for these parameters to lidar measurements of lidar ratio and particle depolarization ratio. Differences particularly exist at 355 nm, which may be the result of differences of the wavelength-dependent complex refractive index that is inferred by the methods employed in this field campaign. We discuss various error sources that may lead to the observed differences.

  18. Heterogeneous nucleation as a potential sulphate-coating mechanism of atmospheric mineral dust particles and implications of coated dust on new particle formation

    NASA Astrophysics Data System (ADS)

    Korhonen, H.; Napari, I.; Timmreck, C.; VehkamäKi, H.; Pirjola, L.; Lehtinen, K. E. J.; Lauri, A.; Kulmala, M.

    2003-09-01

    The plausibility of heterogeneous conucleation of water, sulphuric acid, and ammonia as a pathway leading to soluble coating of atmospheric mineral dust is investigated. In addition, the effect of such sulphate-coated dust on the formation and growth of atmospheric aerosol particles is addressed. The simulated new particle formation mechanism is ternary nucleation of water, sulphuric acid, and ammonia vapors, while in the condensational growth process the effect of condensable organic vapor is also studied. The results indicate that soluble coating of dust by heterogeneous nucleation can occur at atmospheric sulphuric acid concentrations. In addition, the simulations show that homogeneous ternary nucleation and subsequent growth are decoupled. Although observed (or even higher) dust concentrations are unable to inhibit new particle formation, coated dust particles acting as condensation and coagulation sinks can prevent the growth of newly formed particles to detectable sizes. This is particularly true in desert areas, where organic vapor concentrations are low.

  19. The competition between mineral dust and soot ice nuclei in mixed-phase clouds (Invited)

    NASA Astrophysics Data System (ADS)

    Murray, B. J.; Atkinson, J.; Umo, N.; Browse, J.; Woodhouse, M. T.; Whale, T.; Baustian, K. J.; Carslaw, K. S.; Dobbie, S.; O'Sullivan, D.; Malkin, T. L.

    2013-12-01

    The amount of ice present in mixed-phase clouds, which contain both supercooled liquid water droplets and ice particles, affects cloud extent, lifetime, particle size and radiative properties. The freezing of cloud droplets can be catalysed by the presence of aerosol particles known as ice nuclei. In this talk our recent laboratory and global aerosol modelling work on mineral dust and soot ice nuclei will be presented. We have performed immersion mode experiments to quantify ice nucleation by the individual minerals which make up desert mineral dusts and have shown that the feldspar component, rather than the clay component, is most important for ice nucleation (Atkinson et al. 2013). Experiments with well-characterised soot generated with eugenol, an intermediate in biomass burning, and n-decane show soot has a significant ice nucleation activity in mixed-phase cloud conditions. Our results for soot are in good agreement with previous results for acetylene soot (DeMott, 1990), but extend the efficiency to much higher temperatures. We then use a global aerosol model (GLOMAP) to map the distribution of soot and feldspar particles on a global basis. We show that below about -15oC that dust and soot together can explain most observed ice nuclei in the Earth's atmosphere, while at warmer temperatures other ice nuclei types are needed. We show that in some regions soot is the most important ice nuclei (below -15oC), while in others feldspar dust dominates. Our results suggest that there is a strong anthropogenic contribution to the ice nuclei population, since a large proportion of soot aerosol in the atmosphere results from human activities. Atkinson, J. D., Murray, B. J., Woodhouse, M. T., Carslaw, K. S., Whale, T. F., Baustian, K. J., Dobbie, S., O'Sullivan, D., and Malkin, T. L.: The importance of feldspar for ice nucleation by mineral dust in mixed-phase clouds, Nature, 10.1038/nature12278, (2013). Demott, P. J. 1990. An Exploratory-Study of Ice Nucleation by Soot

  20. Ice Nucleation of Bare and Sulfuric Acid-coated Mineral Dust Particles and Implication for Cloud Properties

    SciTech Connect

    Kulkarni, Gourihar R.; Sanders, Cassandra N.; Zhang, Kai; Liu, Xiaohong; Zhao, Chun

    2014-08-27

    Ice nucleation properties of different dust species coated with soluble material are not well understood. We determined the ice nucleation ability of bare and sulfuric acid coated mineral dust particles as a function of temperature (-25 to -35 deg C) and relative humidity with respect to water (RHw). Five different mineral dust species: Arizona test dust (ATD), illite, montmorillonite, quartz and kaolinite were dry dispersed and size-selected at 150 nm and exposed to sulfuric acid vapors in the coating apparatus. The condensed sulfuric acid soluble mass fraction per particle was estimated from the cloud condensation nuclei activated fraction measurements. The fraction of dust particles nucleating ice at various temperatures and RHw was determined using a compact ice chamber. In water-subsaturated conditions, compared to bare dust particles, we found that only coated ATD particles showed suppression of ice nucleation ability while other four dust species did not showed the effect of coating on the fraction of particles nucleating ice. The results suggest that interactions between the dust surface and sulfuric acid vapor are important, such that interactions may or may not modify the surface via chemical reactions with sulfuric acid. At water-supersaturated conditions we did not observed the effect of coating, i.e. the bare and coated dust particles had similar ice nucleation behavior.

  1. Atmospheric delivery of anthropogenic bioavailable iron from mineral dust to the ocean

    NASA Astrophysics Data System (ADS)

    Ito, A.; Shi, Z.

    2015-12-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. Here, we interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. We firstly examined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate). We then constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water, by using acidity as a master variable. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean. However, our modeled Fe solubility was significantly lower than that deduced from observations over the South Atlantic east downwind from the Patagonian dust source regions. Our modeled Fe solubility for dry deposition over the Atlantic is in good agreement the measurement, while that for wet deposition is significantly lower than the measurement. Our model results suggest that human activities contribute to about half of the soluble Fe supply to a significant portion of the oceans in the Northern Hemisphere, while their contribution to oceans in the high latitude remains highly uncertain

  2. The heterogeneous chemical kinetics of NO3 on atmospheric mineral dust surrogates.

    PubMed

    Karagulian, Federico; Rossi, Michel J

    2005-09-01

    Uptake experiments of NO3 on mineral dust powder were carried out under continuous molecular flow conditions at 298 +/- 2 K using the thermal decomposition of N2O5 as NO3 source. In situ laser detection using resonance enhanced multiphoton ionization (REMPI) to specifically detect NO2 and NO in the presence of N2O5, NO3 and HNO3 was employed in addition to beam-sampling mass spectrometry. At [NO3] = (7.0 +/- 1.0) x 10(11) cm(-3) we found a steady state uptake coefficient gamma(ss) ranging from (3.4 +/- 1.6) x 10(-2) for natural limestone to (0.12 +/- 0.08) for Saharan Dust with gamma(ss) decreasing as [NO3] increased. NO3 adsorbed on mineral dust leads to uptake of NO2 in an Eley-Rideal mechanism that usually is not taken up in the absence of NO3. The disappearance of NO3 was in part accompanied by the formation of N2O5 and HNO3 in the presence of NO2. NO3 uptake performed on small amounts of Kaolinite and CaCO3 leads to formation of some N2O5 according to NO((3ads)) + NO(2(g)) --> N2O(5(ads)) --> N2O(5(g)). Slow formation of gas phase HNO3 on Kaolinite, CaCO3, Arizona Test Dust and natural limestone has also been observed and is clearly related to the presence of adsorbed water involved in the heterogeneous hydrolysis of N2O(5(ads)).

  3. Carbonaceous aerosols and mineral dust in atmospheric outflow from the Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Sarin, M.; Srinivas, B.; Rengarajan, R.

    2012-12-01

    Atmospheric carbonaceous aerosols and mineral dust over south and south-east Asia has been a subject of major debate over the past two decades because of their potential impact on the regional air quality and climate forcing. A comprehensive study through ground-based measurements and data-base for aerosol chemical composition (involving both organic and inorganic constituents) is, thus, essential to constrain the large uncertainties associated with the climate impact. Our systematic study from a downwind site (Kharagpur: 22.02N, 87.11E) in the Indo-Gangetic Plain (IGP) suggests large temporal variability in the atmospheric mass concentrations of mineral dust, organic and elemental carbon (OC, EC), water-soluble organic carbon (WSOC) and inorganic species (WSIS). This is attributed to seasonally varying anthropogenic emissions, their source strength, boundary layer dynamics, secondary aerosol formation and long-range transport of mineral dust from desert regions. Based on diagnostic ratios [OC/EC ≈ 7.0 ± 2.2, WSOC/OC ≈ 0.6 and K+/EC ≈ 0.48 ± 0.17], we document biomass burning emissions (wood-fuel and post-harvest agricultural-waste burning) as a major source of carbonaceous aerosols. The characteristic ratios: nss-SO42-/EC (3.9 ± 2.1), nss-SO42-/OC (0.61 ± 0.46), high abundance of SO42- (6.9 - 25.3 μg m-3) and SO42-/ΣWSIS = 45 - 77 % in the outflow provide better assessment of aerosol optical properties. The subsequent downwind transport of pollutants from the IGP significantly influences the chemical composition of aerosols over the Bay of Bengal. The dominance of aerosol SO42- in the marine atmospheric boundary layer (MABL) is evident from the wide-spread depletion of chloride with respect to sea-salt composition. The Ca/Al and Fe/Al ratios in the IGP-outflow, used as a proxy for the long-range transport of mineral dust, are consistent with those in the MABL. The mass closure for PM2.5 composition suggests that contribution of mineral dust (20

  4. High-resolution mineral dust and sea ice proxy records from the Talos Dome ice core

    NASA Astrophysics Data System (ADS)

    Schüpbach, S.; Federer, U.; Kaufmann, P. R.; Albani, S.; Barbante, C.; Stocker, T. F.; Fischer, H.

    2013-12-01

    In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years (ka) before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model, we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large-scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 ka. Our transport model applied on ice core data is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records also allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean during the transition from the Last Glacial Maximum to the Holocene (T1). While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EPICA Dronning Maud Land (EDML) are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea

  5. The immersion freezing behavior of the mixture of mineral dust and biological substances

    NASA Astrophysics Data System (ADS)

    Augustin, S.; Schneider, J.; Schmidt, S.; Niedermeier, D.; Ebert, M.; Voigtländer, J.; Stratmann, F.; Wex, H.

    2013-12-01

    Ice nucleation in the atmosphere has been observed at temperatures higher than -20°C (e.g. Kanitz et al., 2011). In contrast, laboratory studies showed that the most abundant atmospheric ice nuclei (IN), i.e., mineral dust particles, are ice active at much lower temperatures (e.g. Murray et al., 2012). Biological particles such as bacteria or pollen nucleate ice at temperatures similar to those observed in the atmosphere. However, their numbers seem to be too small to explain atmospheric ice nucleation (Hoose et al., 2010). Recent studies suggest, that ice nucleation active (INA) macromolecules, i.e. protein complexes in the case of bacteria (e.g. Wolber et al., 1986), and most likely polysaccharides in the case of pollen (Pummer et al., 2012), which are responsible for the freezing, maintain their nucleating ability even when they are separated from their original carriers (bacterial cell or pollen grain, Hartmann et al., 2013; Augustin et al., 2012). This opens the possibility of accumulation of such INA macromolecules in e.g. soils and the resulting particles could be an internal mixture of mineral dust and INA macromolecules. If such biological IN containing soil particles are then dispersed into the atmosphere due to e.g. wind erosion or agricultural processes they could induce ice nucleation at temperatures higher then -20°C. To explore this hypothesis, we investigated the ice nucleation behavior of mineral dust particles internally mixed with INA macromolecules. Specifically, we mixed pure mineral dust (Illit) with INA biological material (SNOMAX and birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). Augustin, S., Hartmann, S., Pummer, B., Grothe, H., Niedermeier, D., Clauss, T., Voigtländer, J., Tomsche, L, Wex, H. and Stratmann, F., Atmos. Chem. Phys. Discuss., 12, 32911-32943, 2012. Hartmann, S., Augustin, S.,D. Niedermeier, J

  6. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    NASA Astrophysics Data System (ADS)

    Ito, A.; Shi, Z.

    2015-08-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. Here, we, for the first time, interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. We firstly examined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate). We then constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water, by using acidity as a master variable. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean (i.e., 1-2 orders of magnitude lower Fe solubility in North African- than combustion-influenced aerosols). The model results show a positive relationship between Fe solubility and water soluble organic carbon (WSOC)/Fe molar ratio, which is consistent with previous field measurements. We estimated that deposition of soluble Fe to the ocean increased from 0.05-0.07 Tg Fe yr-1 in preindustrial era to 0.11-0.12 Tg Fe yr-1 in present days, due to air pollution. Over the High Nitrate Low Chlorophyll (HNLC) regions of the ocean, the modeled Fe solubility remains low for

  7. Impact of surface roughness and soil texture on mineral dust emission fluxes modeling

    NASA Astrophysics Data System (ADS)

    Menut, Laurent; PéRez, Carlos; Haustein, Karsten; Bessagnet, Bertrand; Prigent, Catherine; Alfaro, StéPhane

    2013-06-01

    Dust production models (DPM) used to estimate vertical fluxes of mineral dust aerosols over arid regions need accurate data on soil and surface properties. The Laboratoire Inter-Universitaire des Systemes Atmospheriques (LISA) data set was developed for Northern Africa, the Middle East, and East Asia. This regional data set was built through dedicated field campaigns and include, among others, the aerodynamic roughness length, the smooth roughness length of the erodible fraction of the surface, and the dry (undisturbed) soil size distribution. Recently, satellite-derived roughness length and high-resolution soil texture data sets at the global scale have emerged and provide the opportunity for the use of advanced schemes in global models. This paper analyzes the behavior of the ERS satellite-derived global roughness length and the State Soil Geographic data base-Food and Agriculture Organization of the United Nations (STATSGO-FAO) soil texture data set (based on wet techniques) using an advanced DPM in comparison to the LISA data set over Northern Africa and the Middle East. We explore the sensitivity of the drag partition scheme (a critical component of the DPM) and of the dust vertical fluxes (intensity and spatial patterns) to the roughness length and soil texture data sets. We also compare the use of the drag partition scheme to a widely used preferential source approach in global models. Idealized experiments with prescribed wind speeds show that the ERS and STATSGO-FAO data sets provide realistic spatial patterns of dust emission and friction velocity thresholds in the region. Finally, we evaluate a dust transport model for the period of March to July 2011 with observed aerosol optical depths from Aerosol Robotic Network sites. Results show that ERS and STATSGO-FAO provide realistic simulations in the region.

  8. Impact of Surface Roughness and Soil Texture on Mineral Dust Emission Fluxes Modeling

    NASA Technical Reports Server (NTRS)

    Menut, Laurent; Perez, Carlos; Haustein, Karsten; Bessagnet, Bertrand; Prigent, Catherine; Alfaro, Stephane

    2013-01-01

    Dust production models (DPM) used to estimate vertical fluxes of mineral dust aerosols over arid regions need accurate data on soil and surface properties. The Laboratoire Inter-Universitaire des Systemes Atmospheriques (LISA) data set was developed for Northern Africa, the Middle East, and East Asia. This regional data set was built through dedicated field campaigns and include, among others, the aerodynamic roughness length, the smooth roughness length of the erodible fraction of the surface, and the dry (undisturbed) soil size distribution. Recently, satellite-derived roughness length and high-resolution soil texture data sets at the global scale have emerged and provide the opportunity for the use of advanced schemes in global models. This paper analyzes the behavior of the ERS satellite-derived global roughness length and the State Soil Geographic data base-Food and Agriculture Organization of the United Nations (STATSGO-FAO) soil texture data set (based on wet techniques) using an advanced DPM in comparison to the LISA data set over Northern Africa and the Middle East. We explore the sensitivity of the drag partition scheme (a critical component of the DPM) and of the dust vertical fluxes (intensity and spatial patterns) to the roughness length and soil texture data sets. We also compare the use of the drag partition scheme to a widely used preferential source approach in global models. Idealized experiments with prescribed wind speeds show that the ERS and STATSGO-FAO data sets provide realistic spatial patterns of dust emission and friction velocity thresholds in the region. Finally, we evaluate a dust transport model for the period of March to July 2011 with observed aerosol optical depths from Aerosol Robotic Network sites. Results show that ERS and STATSGO-FAO provide realistic simulations in the region.

  9. Passive airborne dust sampling with the electrostatic dustfall collector: optimization of storage and extraction procedures for endotoxin and glucan measurement.

    PubMed

    Noss, Ilka; Doekes, Gert; Sander, Ingrid; Heederik, Dick J J; Thorne, Peter S; Wouters, Inge M

    2010-08-01

    We recently introduced a passive dust sampling method for airborne endotoxin and glucan exposure assessment-the electrostatic dustfall collector (EDC). In this study, we assessed the effects of different storage and extraction procedures on measured endotoxin and glucan levels, using 12 parallel EDC samples from 10 low exposed indoor environments. Additionally, we compared 2- and 4-week sampling with the prospect of reaching higher dust yields. Endotoxin concentrations were highest after extraction with pyrogen-free water (pf water) + Tween. Phosphate-buffered saline (PBS)-Tween yielded significantly (44%) lower levels, and practically no endotoxin was detected after extraction in pf water without Tween. Glucan levels were highest after extraction in PBS-Tween at 120 degrees C, whereas extracts made in NaOH at room temperature or 120 degrees C were completely negative. Direct extraction from the EDC cloth or sequential extraction after a preceding endotoxin extraction yielded comparable glucan levels. Sample storage at different temperatures before extraction did not affect endotoxin and glucan concentrations. Doubling the sampling duration yielded similar endotoxin and only 50% higher glucan levels. In conclusion, of the tested variables, the extraction medium was the predominant factor affecting endotoxin and glucan yields.

  10. Monitoring airborne dust in a high density coal-fired power station region in North Yorkshire.

    PubMed

    Vallack, H W; Chadwick, M J

    1993-01-01

    Concerns about the levels of dust deposition in the vicinity of coal-fired power stations in North Yorkshire, in particular Drax Power Station, prompted the commissioning of a detailed monitoring study in the area. This paper describes the first two years' work. The first 12-month study concentrated on the village of Barlow close to Drax Power Station, whilst in the second 12-month study, monitoring sites were spread along a transect passing through the power station belt formed by Ferrybridge, Eggborough and Drax Power Stations. Two monitoring sites were common to both 12-month studies, thus giving two years of continuous monitoring. Pairs of wet Frisbee dust deposit gauges (based on inverted Frisbees) were located at each site. Undissolved particulate matter from each gauge was weighed and characterized by microscopic examination of individual particles. The first 12-month study revealed a downward gradient in dust deposition rate and cenosphere content with distance from Drax Power Station. The high cenosphere content at Barlow, especially at the eastern end, suggested that there was a significant contribution from coal-fired power stations. In the second year, the overall pattern of dust deposition rate and cenosphere content across the power station belt suggested that power stations were contributing to higher levels. In particular, relatively high levels were again found at Barlow. Wind direction correlations point to the fly-ash tip next to Drax Power Station as being the source of cenospheres arriving at Barlow. It is concluded that in both years the fly-ash tip Drax Power Station was making a significant contribution to higher than expected dust deposition rates at Barlow, particularly its eastern end. Other villages in the area may also have been affected by dust originating from coal-fired power stations.

  11. Geochemical Evidence for Periods of Increased Mineral Dust Deposition in Patagonian Peat Bogs Since the Last Deglaciation

    NASA Astrophysics Data System (ADS)

    Vanneste, H.; De Vleeschouwer, F.; Mattielli, N. D.; Vanderstraeten, A.; von Scheffer, C.; Piotrowska, N.; Coronato, A.; Le Roux, G.

    2013-12-01

    Atmospheric mineral dust plays an important role in the earth's climate system, influencing atmospheric parameters such as cloud condensation as well as biogeochemical cycles, affecting atmospheric CO2 levels. Antarctic ice core records show that mineral dust deposition has varied in the Southern Hemisphere over glacial-interglacial stages, suggesting major changes in atmospheric circulation. Nevertheless, to make predictions for the near future possible, a better understanding of atmospheric dust load and transport variability in the recent past, is essential. Ombrotrophic peat bogs have proven to provide excellent records of atmospheric dust deposition for the Holocene as their accumulation rates are higher than any other archive. Hence two ombrotrophic peat bogs, located southwest (Karukinka) and southeast (Harberton) on Isla Grande de Tierra del Fuego, were sampled to investigate dust-palaeoclimatic interactions in southern South America since the last deglaciation. Here we present a detailed geochemical (major, trace elements and Nd isotopes) record for both sites. The base of the peat sequences in Karukinka and Harberton were dated by 14C at ca. 8,000 cal yr BP and ca. 16,500 cal yr BP, respectively. The distribution of trace elemental (Sc, REE) concentrations within the cores indicates, besides tephra layers, episodes of increased mineral dust deposition at Harberton and Karukinka. The glacial-interglacial transition can be observed in the Harberton record (at ca. 11,500 cal yr BP), marked by a drop in the dust flux from 102 g/m2/yr to 10 g/m2/yr. The most significant episode of mineral dust deposition at Karukinka is concentrated around 1,600 cal yr BP with a maximum dust flux of 108 g/m2/yr. Its neodymium isotopic signature of -1 suggests crustal admixing, compared to the ɛNd values of ˜2, for both tephra layers.

  12. Opaque minerals of the lunar rocks and dust from mare tranquillitatis.

    PubMed

    Ramdohr, P; Goresey, A E

    1970-01-30

    The opaque minerals in the lunar rocks 10047, 10050, 10057, 10059, 10068 and in the dust were studied. Rock 10047 contains ilmenite as a main component besides Al-bearing chromian ulvöspinel, a new Ti, Fe, Zr, Y, Ca silicate, troilite, cobaltian alpha Fe, minor hafnian baddeleyite and dysanalyte. Dysanalyte contains Ca, Ti, and Fe as major elements and shows concentrations (rare earth elements together approximately 10 percent) of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Hf, Y, and Zr plus traces of Nb, Ba, and Na. The chemistry of ilmenite in the igneous rocks shows no appreciable variations. A new mineral of the solid solution series MgTi(2)O(5)-FeTi(2)O(5) has also been encountered in the polymict breccias. The microbreccias and the fines contain meteorite debris indicating an impact origin.

  13. Characterization of ^{239,240}Pu Radionuclide Adsorption to Soil Particles and Mineral Dust Aerosols

    NASA Astrophysics Data System (ADS)

    Tatro, D. P.; Arimoto, R.; McMillan, N. J.; Barnes, M.

    2006-12-01

    The release of ^{239,240}Pu into the environment by nuclear weapons testing 50 years ago initiated the cyclic mobilization of Pu-contaminated soil particles via the resuspension of dust resulting in a widespread distribution of Pu and other radionuclides. It is unclear what enables the aeolian transport of Pu in the environment; plausible hypotheses of Pu binding to dust and soil particles include Pu adsorption to iron oxides/hydroxides, organic acids, or silicate minerals such as clays. To investigate the connections between surface soils, dust and radionuclides, samples of soil and/or dust were collected from the Project Gnome Site in Eddy County, NM, the Jemez Mountains near Los Alamos, NM, and two 50-year old attics and wind-blown dust in Big Spring, TX. This study tests the hypothesis that Pu is adsorbed onto Fe oxides and hydroxides that coat dust/soil particles. The samples are generally low in organic carbon (0.2 - 4.8%, except for the unburned Los Alamos sample at 9.4%), as measured by LOI (Loss On Ignition) at 360 °C. The citrate-bicarbonate-dithionite method (CDB) of Fe oxide removal, first proposed by Mehra and Jackson in 1960, was used to selectively extract Fe oxides from the samples while leaving silicate Fe intact. Chemical digestion of each sample creates two fractions, the extracted supernatant and a solid pellet residue. If the Pu were associated with Fe oxides, then Fe and Pu should both be selectively removed from the bulk sample during the CBD process, leaving the pellet depleted in Fe and Pu and the supernatant enriched. For Fe, this was confirmed by scanning electron microscope and petrographic analyses. Preliminary radiochemical analyses of Pu activity also verify this hypothesis. Pu activity is significantly lower in pellets than bulk samples (Pu activitypellet/Pu activitybulk average = 0.07, range 0.02-0.12); Pu activity in supernatants is significantly higher than in bulk samples (Pu activitysupernatant/Pu activitybulk average = 4

  14. Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

    NASA Astrophysics Data System (ADS)

    Osada, K.; Ura, S.; Kagawa, M.; Mikami, M.; Tanaka, T. Y.; Matoba, S.; Aoki, K.; Shinoda, M.; Kurosaki, Y.; Hayashi, M.; Shimizu, A.; Uematsu, M.

    2014-01-01

    Recent ground networks and satellite remote-sensing observations have provided useful data related to spatial and vertical distributions of mineral dust particles in the atmosphere. However, measurements of temporal variations and spatial distributions of mineral dust deposition fluxes are limited in terms of their duration, location, and processes of deposition. To ascertain temporal variations and spatial distributions of mineral dust deposition using wet and dry processes, weekly deposition samples were obtained at Sapporo, Toyama, Nagoya, Tottori, Fukuoka, and Cape Hedo (Okinawa) in Japan during October 2008-December 2010 using automatic wet and dry separating samplers. Mineral dust weights in water-insoluble residue were estimated from Fe contents measured using an X-ray fluorescence analyser. Wet and dry deposition fluxes of mineral dusts were both high in spring and low in summer, showing similar seasonal variations to frequency of aeolian dust events (Kosa) in Japan. For wet deposition, highest and lowest annual dust fluxes were found at Toyama (9.6 g m-2 yr-1) and at Cape Hedo (1.7 g m-2 yr-1) as average values in 2009 and 2010. Higher wet deposition fluxes were observed at Toyama and Tottori, where frequent precipitation (> 60% days per month) was observed during dusty seasons. For dry deposition among Toyama, Tottori, Fukuoka, and Cape Hedo, the highest and lowest annual dust fluxes were found respectively at Fukuoka (5.2 g m-2 yr-1) and at Cape Hedo (2.0 g m-2 yr-1) as average values in 2009 and 2010. The average ratio of wet and dry deposition fluxes was the highest at Toyama (3.3) and the lowest at Hedo (0.82), showing a larger contribution of the dry process at western sites, probably because of the distance from desert source regions and because of the effectiveness of the wet process in the dusty season. Size distributions of refractory dust particles were obtained using four-stage filtration: > 20, > 10, > 5, and > 1 μm diameter. Weight fractions

  15. Heavy Metal Content in Airborne Dust of Childhood Leukemia Cluster Areas: Even Small Towns Have Air Pollutants

    NASA Astrophysics Data System (ADS)

    Sheppard, P. R.; Witten, M. L.

    2004-12-01

    Currently in the US, there are at least two ongoing clusters of childhood leukemia, where the incidence rate over the last several years has exceeded the national norm. In Fallon, Nevada, a town of 8,000 people, 16 children have been diagnosed with leukemia since 1995, three of whom have died. In Sierra Vista, Arizona, a town of 38,000 people, 12 children have been diagnosed since 1998, two of whom have died. A possible third cluster of childhood leukemia and other cancers is being monitored in Elk Grove, California, a suburb of Sacramento. For the purpose of characterizing the heavy metal content of airborne dust of these three communities, total suspended particulate samples were collected from each town as well as from nearby towns that could be considered as control comparisons. Sampling was done using portable high-volume blowers and glass- or quartz-fiber filter media. Filters were measured for elemental concentrations using inductively coupled plasma mass spectroscopy. To date, our most notable results are from the Nevada region. Compared to other control towns in the region, Fallon had significantly more tungsten in its airborne dust. Uranium was also higher in dust of Fallon than in other control towns. Uranium is a known health hazard, though it is not necessarily specifically related to childhood leukemia. The role of tungsten in childhood leukemia has not been widely studied. However, other research has identified tungsten exposure as an environmental concern in Fallon. A CDC study of human tissue samples from Fallon has shown high tungsten levels in people of Fallon, and a USGS study of drinking water in Fallon also has shown high tungsten there. Tree-ring research on selected trees has shown high tungsten values in recent rings compared to earlier rings. While these multiple indications of tungsten in the Fallon environment do not directly lead to the conclusion that tungsten causes leukemia, they do combine to suggest that biomedical research on the

  16. Respiratory protection provided by N95 filtering facepiece respirators against airborne dust and microorganisms in agricultural farms.

    PubMed

    Lee, Shu-An; Adhikari, Atin; Grinshpun, Sergey A; McKay, Roy; Shukla, Rakesh; Zeigler, Haoyue Li; Reponen, Tiina

    2005-11-01

    A new system was used to determine the workplace protection factors (WPF) for dust and bioaerosols in agricultural environments. The field study was performed with a subject wearing an N95 filtering facepiece respirator while performing animal feeding, grain harvesting and unloading, and routine investigation of facilities. As expected, the geometric means (GM) of the WPFs increased with increasing particle size ranging from 21 for 0.7-1 microm particles to 270 for 5-10 microm particles (p < 0.001). The WPF for total culturable fungi (GM = 35) was significantly greater than for total culturable bacteria (GM = 9) (p = 0.01). Among the different microorganism groups, the WPFs of Cladosporium, culturable fungi, and total fungi were significantly correlated with the WPFs of particles of the same sizes. As compared with the WPFs for dust particles, the WPFs for bioaerosols were found more frequently below 10, which is a recommended assigned protection factor (APF) for N95 filtering facepiece respirators. More than 50% of the WPFs for microorganisms (mean aerodynamic diameter < 5 microm) were less than the proposed APF of 10. Even lower WPFs were calculated after correcting for dead space and lung deposition. Thus, the APF of 10 for N95 filtering facepiece respirators seems inadequate against microorganisms (mean aerodynamic size < 5 microm). These results provide useful pilot data to establish guidelines for respiratory protection against airborne dust and microorganisms on agricultural farms. The method is a promising tool for further epidemiological and intervention studies in agricultural and other similar occupational and nonoccupational environments. PMID:16234218

  17. Multi-year model simulations of mineral dust distribution and transport over the Indian subcontinent during summer monsoon seasons

    NASA Astrophysics Data System (ADS)

    Sijikumar, S.; Aneesh, S.; Rajeev, K.

    2016-08-01

    Aerosol distribution over the Arabian Sea and the Indian subcontinent during the northern hemispheric summer is dominated by mineral dust transport from the West Asian desert regions. The radiative impact of these dust plumes is expected to have a prominent role in regulating the Asian Summer Monsoon circulation. While satellite observations have provided information in the spatial distribution of aerosols over the oceanic regions during the season, their utility over the land is rather limited. This study examines the transport of mineral dust over the West Asian desert, the Indian subcontinent and the surrounding oceanic regions during the summer monsoon season with the help of a regional scale model, WRF-Chem. Geographical locations of prominent dust sources, altitude ranges of mineral dust transport and their inter-annual variations are examined in detail. Multi-year model simulations were carried out during 2007 to 2012 with a model integration from 15 May to 31 August of each year. Six-year seasonal mean (June to August) vertically integrated dust amount from 1000 to 300 hPa level shows prominent dust loading over the eastern parts of Arabian desert and the northwestern part of India which are identified as two major sources of dust production. Large latitudinal gradient in dust amount is observed over the Arabian Sea with the largest dust concentration over the northwestern part and is primarily caused by the prevailing northwesterly wind at 925 hPa level from the Arabian desert. The model simulations clearly show that most of the dust distributed over the Indo-Gangetic plane originates from the Rajasthan desert located in the northwestern part of India, whereas dust observed over the central and south peninsular India and over the Arabian Sea are mainly transported from the Arabian desert. Abnormal dust loading is observed over the north Arabian Sea during June 2008. This has been produced as a result of the low pressure system (associated with the onset of

  18. Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

    NASA Astrophysics Data System (ADS)

    Osada, K.; Ura, S.; Kagawa, M.; Mikami, M.; Tanaka, T. Y.; Matoba, S.; Aoki, K.; Shinoda, M.; Kurosaki, Y.; Hayashi, M.; Shimizu, A.; Uematsu, M.

    2013-08-01

    Data of temporal variations and spatial distributions of mineral dust deposition fluxes are very limited in terms of duration, location, and processes of deposition. To ascertain temporal variations and spatial distributions of mineral dust deposition by wet and dry processes, weekly deposition samples were obtained at Sapporo, Toyama, Nagoya, Tottori, Fukuoka, and Cape Hedo (Okinawa) in Japan during October 2008-December 2010 using automatic wet and dry separating samplers. Mineral dust weights in water-insoluble residue were estimated from Fe contents measured using an X-ray fluorescence analyzer. For wet deposition, highest and lowest annual dust fluxes were found at Toyama (9.6 g m-2 yr-1) and at Cape Hedo (1.7 g m-2 yr-1) as average values in 2009 and 2010. Higher wet deposition fluxes were observed at Toyama and Tottori, where frequent precipitation (>60% days per month) was observed during dusty seasons. For dry deposition among Toyama, Tottori, Fukuoka, and Cape Hedo, the highest and lowest annual dust fluxes were found respectively at Fukuoka (5.2 g m-2 yr-1) and at Cape Hedo (2.0 g m-2 yr-1) as average values in 2009 and 2010. Although the seasonal tendency of the monthly dry deposition amount roughly resembled that of monthly days of Kosa dust events, the monthly amount of dry deposition was not proportional to monthly days of the events. Comparison of dry deposition fluxes with vertical distribution of dust particles deduced from Lidar data and coarse particle concentrations suggested that the maximum dust layer height or thickness is an important factor for controlling the dry deposition amount after long-range transport of dust particles. Size distributions of refractory dust particles were obtained using four-stage filtration: >20, >10, >5, and >1 μm diameter. Weight fractions of the sum of >20 μm and 10-20 μm (giant fraction) were higher than 50% for most of the event samples. Irrespective of the deposition type, the giant dust fractions were

  19. Dust storm contributions to airborne particulate matter in Reykjavík, Iceland

    NASA Astrophysics Data System (ADS)

    Thorsteinsson, Throstur; Gísladóttir, Guđrún; Bullard, Joanna; McTainsh, Grant

    2011-10-01

    Episodes of high levels of particulate matter (PM) in Reykjavík occur several times a year. The main sources of daily variation in PM are traffic or highly localized (e.g. construction) sources, however several episodes have been identified where these are not the cause. Examining PM10 (diameter < 10 μm) levels around the time when dust storms are seen on satellite images, and verifying that the weather conditions are favorable for the duration of the high levels of PM (>50-100 μg m-3; 30-min average), demonstrates that dust storms are the source of these increased levels of PM10. Since satellite coverage is sparse, visual confirmation of many such peaks in PM10 cannot be achieved. The level of pollution measured in Reykjavík during dust storms indicates that at least 200 kg s-1 of PM10 sized material is being eroded and transported away from sand plains ˜110 km away - this equates to an emission rate of 35 g m2 h-1. The source regions for dust storms in Iceland are the sandur areas on the southern coast of Iceland, and regions close to the glaciers. With climate warming, and fast retreating glaciers, the potential source regions in Iceland are rapidly increasing.

  20. Swine confinement buildings: effects of airborne particles and settled dust on airway smooth muscles.

    PubMed

    Demanche, Annick; Bonlokke, Jakob; Beaulieu, Marie-Josee; Assayag, Evelyne; Cormier, Yvon

    2009-01-01

    Swine confinement workers are exposed to various contaminants. These agents can cause airway inflammation and bronchoconstriction. This study was undertaken to evaluate if the bronchoconstrictive effects of swine barn air and settled dust are mediated by endotoxin, and if these effects are directly mediated on airway smooth muscles. Mouse tracheas where isolated and mounted isometrically in organ baths. Tracheas, with or without epithelium, were attached to a force transducer and tension was recorded. Concentrated swine building air at 68 EU/ml or settled dust extract at 0.01 g/ml were added for 20 minutes and tracheal smooth muscle contraction was measured. Direct role of LPS was assessed by removing it from air concentrates with an endotoxin affinity resin. Swine barn air and settled dust extract caused contraction of tracheal smooth muscle by 26 and 20%, respectively, of the maximal induced by methacholine. Removal of epithelium did not affect the contractile effects. LPS alone and LPS with peptidoglycans did not induce contraction. However, when endotoxin was removed from swine barn air concentrates, it lost 24% of its contractile effect. Concentrated swine barn air and settled dust have direct effects on airway smooth muscles. This effect is partially due to LPS but a synergy with other components of the environment of swine confinement buildings is required. PMID:20047256

  1. Transport of mineral dust to Nepal Climate Observatory - Pyramid (5079 m a.s.l., South Himalayas)

    NASA Astrophysics Data System (ADS)

    Duchi, Rocco; Cristofanelli, Paolo; Marinoni, Angela; Calzolari, Francescopiero; Decesari, Stefano; Laj, Paolo; Vuillermoz, Elisa; Sprenger, Michael; Bonasoni, Paolo

    2010-05-01

    Desert dust is one of the greatest sources of natural aerosol in atmosphere, representing about 37% of the total (natural and anthropogenic) emission of atmospheric primary aerosols. Mineral dust can impact climate through many complex processes, i.e. by scattering and absorbing solar and infrared radiation and by affecting the variability of cloud aerosol optical properties. Moreover, mineral dust can also affect the concentrations of other climate-altering species (e.g. surface ozone) in troposphere. South Asia is a region frequently affected by major dust transport from Africa and Asia. In particular, these "dust clouds" can reach the Himalayas also mixed with the heavy anthropogenic pollution present within the so-called Asian Brown Cloud. With the purpose to define the frequency of long-range mineral dust transport towards the Himalayan range and to evaluate their influence on the atmospheric aerosol background level, in this work we analyse the first 2-year (from March 2006 to February 2008) of coarse (Dp > 1 micron) aerosol number concentration observed at the WMO - GAW station "Nepal Climate Observatory - Pyramid" (NCO-P, 5079 m a.s.l., Nepal). This measurement station, part of UNEP-ABC and EV-K2-CNR SHARE projects, is not far from the Everest Base Camp and the observation here conducted can be considered representative for the South-Eastern slope of the Himalayan range. During the investigated period we detect more than 80 days/year as possibly affected by mineral dust transport. As deduced by the NCO-P measurements, these events significantly influenced the seasonal variation of coarse aerosol number concentration as well as the number and volumetric aerosol size distribution over South Himalayas. Due to the combination of the large-scale westerly circulation and the higher frequency of dust out-breaks, the majority of the identified events occurred during the pre-monsoon season. Although of lesser intensity and frequency, a significant amount of dust

  2. Lidar measurements of Raman scattering at ultraviolet wavelength from mineral dust over East Asia.

    PubMed

    Tatarov, Boyan; Müller, Detlef; Shin, Dong Ho; Shin, Sung Kyun; Mattis, Ina; Seifert, Patric; Noh, Young Min; Kim, Y J; Sugimoto, Nobuo

    2011-01-17

    We developed a novel measurement channel that utilizes Raman scattering from silicon dioxide (SiO2) quartz at an ultraviolet wavelength (361 nm). The excitation of the Raman signals is done at the primary wavelength of 355 nm emitted from a lidar instrument. In combination with Raman signals from scattering from nitrogen molecules, we may infer the mineral-quartz-related backscatter coefficient. This technique thus allows us to identify in a comparably direct way the mineral quartz content in mixed pollution plumes that consist, e.g., of a mix of desert dust and urban pollution. We tested the channel for the complex situation of East Asian pollution. We find good agreement of the inferred mineral-quartz-related backscatter coefficient to results obtained with another mineral quartz channel which was operated at 546 nm (primary emission wavelength at 532 nm), the functionality of which has already been shown for a lidar system in Tsukuba (Japan). The advantage of the novel channel is that it provides a better signal-to-noise ratio because of the shorter measurement wavelength.

  3. Emphysema and pulmonary impairment in coal miners: Quantitative relationship with dust exposure and cigarette smoking

    NASA Astrophysics Data System (ADS)

    Kuempel, E. D.; Vallyathan, V.; Green, F. H. Y.

    2009-02-01

    Coal miners have been shown to be at increased risk of developing chronic obstructive pulmonary diseases including emphysema. The objective of this study was to determine whether lifetime cumulative exposure to respirable coal mine dust is a significant predictor of developing emphysema at a clinically-relevant level of severity by the end of life, after controlling for cigarette smoking and other covariates. Clinically-relevant emphysema severity was determined from the association between individuals' lung function during life (forced expiratory volume in one second, FEV1, as a percentage of predicted normal values) and emphysema severity at autopsy (as the proportion of lung tissue affected). In a logistic regression model, cumulative exposure to respirable coal mine dust was a statistically significant predictor of developing clinically-relevant emphysema severity, among both ever-smokers and never-smokers. The odds ratio for developing emphysema associated with FEV1 <80% at the cohort mean cumulative coal dust exposure (87 mg/m3 x yr) was 2.30 (1.46-3.64, 95% confidence limits), and at the cohort mean cigarette smoking (among smokers: 42 pack-years) was 1.95 (1.39-2.79).

  4. Heterogeneous Reaction of SO2 on Authentic Mineral Dusts: Effects of Relative Humidity and H2O2

    NASA Astrophysics Data System (ADS)

    Huang, L.; Li, H.; Zhao, Y.; Chen, Z.

    2014-12-01

    Sulfur dioxide (SO2) is a significant precursor of sulfuric acid and sulfate aerosols in the atmosphere. Field and model studies have revealed that heterogeneous reaction on mineral dusts seem to be an important sink for SO2. However, available kinetic data about heterogeneous reaction of SO2 on authentic mineral dusts are scarce and are mainly limited at low humidity relative (RH). In addition, hydrogen peroxide (H2O2), which is the predominant oxidant of SO2 in the aqueous phase, may be able to promote the heterogeneous oxidation of SO2 on mineral dusts, but little is known about this role that H2O2 may play. In this study, we investigated the uptake kinetics of SO2 on authentic mineral dusts in the absence and presence of H2O2 at different RHs using a filter-based reactor. Three different authentic mineral dusts, i.e., Asian dust storm particles (ADS), Arizona test dust (ATD) and Tengger Desert sand (TDS), were used. The initial gas phase concentration of SO2 and H2O2 is about 5 ppbv and 0.8 ppbv, respectively, the typical concentration in the atmosphere. The values of uptake coefficients, γBET, on these particles are on the order of 10-5 under dry condition. Interestingly, with increasing RH, the γBET decreases on ADS particles, but increases on ATD and TDS particles. The difference in the mineralogy composition of these dust samples seems to rationalize the discrepancy in SO2 uptake. Furthermore, it is found that the presence of H2O2 increases the γBET by 45-90% on ADS, 45-150% on ATD and 40%-105% on TDS as RH increases 0 to 90%. One possible explanation for the observed behavior are that H2O2 can immediately react with SO2 on the surface of mineral dusts. Our results suggest that the role of heterogeneous reaction on mineral dusts as a sink of SO2 or a source of sulfate in the atmosphere may be underestimated due to the excluding of the enhancement effect of H2O2 in current atmospheric models.

  5. Heterogeneous Chemistry of Individual Mineral Dust Particles with Nitric Acid. A Combined CCSEM/EDX, ESEM AND ICP-MS Study

    SciTech Connect

    Laskin, Alexander; Wietsma, Thomas W.; Krueger, Brenda J.; Grassian, Vicki H.

    2005-05-26

    The heterogeneous chemistry of individual dust particles from four authentic dust samples with gas-phase nitric acid was investigated in this study. Morphology and compositional changes of individual particles as they react with nitric acid were observed using conventional scanning electron microscopy with energy dispersive analysis of X-rays (SEM/EDX) and computer controlled SEM/EDX. Environmental Scanning Electron Microscopy (ESEM) was utilized to investigate the hygroscopic behavior of mineral dust particles reacted with nitric acid. Differences in the reactivity of mineral dust particles from these four different dust source regions with nitric acid were observed. Mineral dust from source regions containing high levels of calcium, namely China loess dust and Saudi coastal dust, were found to react to the greatest extent.

  6. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    NASA Astrophysics Data System (ADS)

    Ito, A.; Shi, Z.

    2016-01-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. In this study, for the first time, we interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. Firstly, we determined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate). Then, by using acidity as a master variable, we constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean (i.e., 1-2 orders of magnitude lower Fe solubility in northern-African- than combustion-influenced aerosols). The model results show a positive relationship between Fe solubility and water-soluble organic carbon (WSOC)/Fe molar ratio, which is consistent with previous field measurements. We estimated that deposition of soluble Fe to the ocean increased from 0.05-0.07 Tg Fe yr-1 in the preindustrial era to 0.11-0.12 Tg Fe yr-1 in the present day, due to air pollution. Over the high-nitrate, low-chlorophyll (HNLC) regions of the ocean, the modeled Fe

  7. Chinese mineral dust and anthropogenic aerosol inter-continental transport: a Greenland perspective

    NASA Astrophysics Data System (ADS)

    Bory, A.; Abouchami, W.; Galer, S.; Svensson, A.; Biscaye, P.

    2012-04-01

    Impurities contained in snow and ice layers in Greenland provide a record of the history of atmospheric dustiness and pollution in the Northern Hemisphere. The source of the particles deposited onto the ice cap may be investigated using specific intrinsic tracers. Provenance discrimination may then provide valuable constraints for the validation of atmospheric transport models as well as for the monitoring of natural and anthropogenic aerosols emissions at a global scale. Clay mineralogy combined with the strontium and neodymium isotope composition of the insoluble particles extracted from recent snow deposits at NorthGRIP (75.1°N, 042.3°W), for instance, enabled us to demonstrate that the Taklimakan desert of North-western China was the main source of mineral dust reaching central Greenland at present [Bory et al., EPSL, 2002 ; GRL, 2003a]. Here we report the lead isotopic signature of these snow-pit samples, covering the 1989-1995 and 1998-2001 time periods. Unradiogenic lead isotopic composition of our Greenland samples, compared to Asian dust isotopic fingerprints, implies that most of the insoluble lead reaching the ice cap is of anthropogenic origin. Lead isotopes reveal likely contributions from European/Canadian and, to a lesser extent, US sources, as well as a marked overprinted signature typical of Chinese anthropogenic lead sources. The relative contribution of the latter appears to have been increasing steadily over the last decade of the 20th century. Quantitative estimates suggest that, in addition to providing most of the dust, China may have already become the most important supplier of anthropogenic lead deposited in Greenland by the turn of the 20th to the 21st century. The close timing between dust and anthropogenic particles deposition onto the ice cap provides new insights for our understanding of Chinese aerosols transport to Greenland.

  8. Iron oxide minerals in dust of the Red Dawn event in eastern Australia, September 2009

    NASA Astrophysics Data System (ADS)

    Reynolds, Richard L.; Cattle, Stephen R.; Moskowitz, Bruce M.; Goldstein, Harland L.; Yauk, Kimberly; Flagg, Cody B.; Berquó, Thelma S.; Kokaly, Raymond F.; Morman, Suzette; Breit, George N.

    2014-12-01

    Iron oxide minerals typically compose only a few weight percent of bulk atmospheric dust but are important for potential roles in forcing climate, affecting cloud properties, influencing rates of snow and ice melt, and fertilizing marine phytoplankton. Dust samples collected from locations across eastern Australia (Lake Cowal, Orange, Hornsby, and Sydney) following the spectacular "Red Dawn" dust storm on 23 September 2009 enabled study of the dust iron oxide assemblage using a combination of magnetic measurements, Mössbauer spectroscopy, reflectance spectroscopy, and scanning electron microscopy. Red Dawn was the worst dust storm to have hit the city of Sydney in more than 60 years, and it also deposited dust into the Tasman Sea and onto snow cover in New Zealand. Magnetization measurements from 20 to 400 K reveal that hematite, goethite, and trace amounts of magnetite are present in all samples. Magnetite concentrations (as much as 0.29 wt%) were much higher in eastern, urban sites than in western, agricultural sites in central New South Wales (0.01 wt%), strongly suggesting addition of magnetite from local urban sources. Variable temperature Mössbauer spectroscopy (300 and 4.2 K) indicates that goethite and hematite compose approximately 25-45% of the Fe-bearing phases in samples from the inland sites of Orange and Lake Cowal. Hematite was observed at both temperatures but goethite only at 4.2 K, thereby revealing the presence of nanogoethite (less than about 20 nm). Similarly, hematite particulate matter is very small (some of it d < 100 nm) on the basis of magnetic results and Mössbauer spectra. The degree to which ferric oxide in these samples might absorb solar radiation is estimated by comparing reflectance values with a magnetic parameter (hard isothermal remanent magnetization, HIRM) for ferric oxide abundance. Average visible reflectance and HIRM are correlated as a group (r2 = 0.24), indicating that Red Dawn ferric oxides have capacity to absorb

  9. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    DOE PAGES

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.; Albani, S.

    2015-01-15

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale, using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral componentsmore » in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as + 0.05 Wm−2 for both CAM4 and CAM5 simulations with mineralogy. We compare this to the radiative forcing from simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 Wm−2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, −0.05 and −0.17 Wm−2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.« less

  10. Modeling dust as component minerals in the Community Atmosphere Model: development of framework and impact on radiative forcing

    DOE PAGES

    Scanza, R. A.; Mahowald, N.; Ghan, S.; Zender, C. S.; Kok, J. F.; Liu, X.; Zhang, Y.

    2014-07-02

    The mineralogy of desert dust is important due to its effect on radiation, clouds and biogeochemical cycling of trace nutrients. This study presents the simulation of dust radiative forcing as a function of both mineral composition and size at the global scale using mineral soil maps for estimating emissions. Externally mixed mineral aerosols in the bulk aerosol module in the Community Atmosphere Model version 4 (CAM4) and internally mixed mineral aerosols in the modal aerosol module in the Community Atmosphere Model version 5.1 (CAM5) embedded in the Community Earth System Model version 1.0.5 (CESM) are speciated into common mineral componentsmore » in place of total dust. The simulations with mineralogy are compared to available observations of mineral atmospheric distribution and deposition along with observations of clear-sky radiative forcing efficiency. Based on these simulations, we estimate the all-sky direct radiative forcing at the top of the atmosphere as +0.05 W m−2 for both CAM4 and CAM5 simulations with mineralogy and compare this both with simulations of dust in release versions of CAM4 and CAM5 (+0.08 and +0.17 W m−2) and of dust with optimized optical properties, wet scavenging and particle size distribution in CAM4 and CAM5, −0.05 and −0.17 W m−2, respectively. The ability to correctly include the mineralogy of dust in climate models is hindered by its spatial and temporal variability as well as insufficient global in-situ observations, incomplete and uncertain source mineralogies and the uncertainties associated with data retrieved from remote sensing methods.« less

  11. Global trends in mineral dust aerosol: determining causes and attributing uncertainty with the GEOS-Chem model

    NASA Astrophysics Data System (ADS)

    Ridley, D. A.; Heald, C. L.; Prospero, J. M.

    2014-12-01

    Mineral dust aerosol constitutes a large fraction of the total aerosol burden, which presents health risks, alters atmospheric chemistry, and strongly perturbs the radiative balance over large regions. Therefore, it is imperative that we understand what controls the observed trends and changes in variability of dust emissions. Recently, we have shown that the observed reduction in African dust loading over the Atlantic in recent decades is likely driven by large-scale wind changes over source regions rather than changes in vegetation cover. Using an updated dust emission scheme and information from high resolution (0.25 degree) simulations from the NASA GEOS model, we attribute the uncertainty in modeled dust AOD and expand the analysis to other regions of the world, including Asia and the Middle East.

  12. Effect of mineral dust on ocean color retrievals from space: A radiative transfer simulation study

    NASA Astrophysics Data System (ADS)

    Ahmad, Z.; Franz, B. A.

    2014-12-01

    Mineral aerosols (dust) are one of the major components of all aerosols found in the Earth's atmosphere. They are mainly soil particles that originate from arid and semiarid regions of the world that can be carried by winds for thousands of kilometers. They are a major impediment in the remote sensing of the ocean color (spectral water-leaving reflectance), because they absorb solar radiation in the UV and visible part of the spectrum and their micro-physical and optical properties are highly variable. Further, there are no reliable working algorithms to detect their presence from spaceborne ocean color observations alone, when they are present in small amount (optical thickness < 0.2). In this paper we examine effect of mineral dust on ocean color retrieval from space. We use Ahmad-Fraser's vector radiative transfer (RT) code (v3.0) for ocean-atmosphere system to simulate the pseudo observations (top of atmosphere radiance) for models containing different types of aerosols (absorbing and non-absorbing) in the atmosphere. We consider the mineral aerosols as consisting of an external mixture of illite, kaolinite, montmorillonite, quartz, and calcite with a small amount of hematite (as an internal mixture), which provide the spectral dependence of single scattering albedo consistent with the values reported in the literature. We also vary the aerosol layer height in the atmosphere and amount of chlorophyll in the ocean. The simulated pseudo observations were processed through standard NASA algorithms to determine the ocean color (spectral water-leaving reflectance) and derived chlorophyll in the ocean. Results of the RT simulation study for different Sun-satellite viewing geometry, aerosol layer height and chlorophyll amount in the ocean is presented.

  13. Characterisation of mineral dust emission in the Middle EAST using the Spinning Enhanced Visible and Infrared Imager (SEVIRI)

    NASA Astrophysics Data System (ADS)

    Hennen, M.; Shahgedanova, M.; White, K.

    2015-12-01

    Using the Spinning Enhanced Visual and InfraRed Imager (SEVIRI) on-board Meteosat's second generation satellite (MSG), mineral dust emissions from the Middle East were observed at a high temporal and spatial resolution between the years 2006 and 2013. This research provides a subjective derivation of mineral dust source locations in the Middle East using the thermal infrared Dust RGB product. Focusing on the brightness temperature difference around 10.8 µm channel and their spectral contrast with clear sky conditions, the Dust RGB product has been recognised as a major asset in detecting dust. While the product has already been used to map dust emissions in Sahara and south Africa, this research is the first to map dust emissions in the Middle East using SEVIRI, one of the dustiest regions in the world second only to the Sahara Desert. For every dust storm activation within the Middle East, the point of first emission is derived from visual inspection of each 15 minute image, these points were then recorded in a dust source climatology (DSC) database, along with time and direction of dust movement. To take account of potential errors inherent in this subjective detection method, a degree of confidence is associated with each data point with relevance to time of day (which has a strong effect on ability to detect dust in these products) and weather conditions, in particular presence of clouds. These results are compared with an automated retrieval using Aerosol Optical Depth (AOD) measurements form the Moderate Resolution Image Spectrometer (MODIS); which, due to its sun-synchronous orbit allows a measurement of dust in the atmosphere once a day. Differences in the spatial distribution of SEVIRI dust sources and MODIS inferred dust source regions can be explained by inherent transport bias in the latter's low sampling rate and prevailing wind conditions. This database will provide an important tool in further understanding dust emission processes in the region

  14. Global distribution of mineral dust and its impact on radiative fluxes as simulated by WRF-Chem

    NASA Astrophysics Data System (ADS)

    Alizadeh-Choobari, Omid; Sturman, Andrew; Zawar-Reza, Peyman

    2015-12-01

    Dust aerosols make a considerable contribution to the climate system and atmospheric hydrological cycle through their radiative and ice nuclei effects. This underlines the need for investigating the sources of dust aerosols, their transport pathways, and radiative forcing. Seasonal distribution of mineral dust around the globe and its impact on radiation fluxes is estimated using two simulations: a model setup that did not include dust aerosols; and an interactive experiment that included dust aerosols and their feedback to the atmosphere. Simulations were performed by the Weather Research and Forecasting with Chemistry (WRF-Chem) model for a 1-year period. The global annual mean dust optical depth (DOD) at 0.55 \\upmum is estimated to be 0.057, with a spring peak value of 0.081 and an autumn minimum value of 0.039. Seasonal variation of atmospheric dust loading is shown to be associated with similar significant variation in shortwave and longwave direct radiation perturbation by dust, both at the surface and top of the atmosphere (TOA). The presence of mineral dust in the interactive simulation is estimated to exert a maximum net direct radiation perturbation in summer with values of -2.85 and -1.63 W m^{-2} in clear-sky conditions at the surface and TOA, respectively. It also exerts a global annual net direct radiation perturbation of -1.86 and -1.09 W m^{-2} at the surface and TOA, respectively. The surface cooling is attributed to the extinction of incoming solar radiation by dust aerosols, while negative perturbation at the TOA (which demonstrates cooling of the Earth-atmosphere system) is predominantly attributed to an increase in outgoing shortwave radiation.

  15. A global satellite view of the seasonal distribution of mineral dust and its correlation with atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Alizadeh-Choobari, O.; Sturman, A.; Zawar-Reza, P.

    2014-12-01

    Aerosols make a considerable contribution to the climate system through their radiative and cloud condensation nuclei effects, which underlines the need for understanding the origin of aerosols and their transport pathways. Seasonal distribution of mineral dust around the globe and its correlation with atmospheric circulation is investigated using satellite data, and meteorological data from ECMWF. The most important sources of dust are located in North Africa, the Middle East and Southwest Asia with an observed summer maximum, and East Asia with a spring peak. Maximum dust activity over North Africa and the Middle East in summer is attributed to dry convection associated with the summertime low-pressure system, while unstable weather and dry conditions are responsible for the spring peak in dust emission in East Asia. Intercontinental transport of mineral dust by atmospheric circulation has been observed, including trans-Atlantic transport of North African dust, trans-Pacific transport of Asian dust, and transport of dust from the Middle East across the Indian Ocean. The extent of African dust over the Atlantic Ocean and its latitudinal variation with season is related to the large-scale atmospheric circulation, including seasonal changes in the position of the intertropical convergence zone (ITCZ) and variation of wind patterns. North African aerosols extend over longer distances across the North Atlantic in summer because of greater dust emission, an intensified easterly low level jet (LLJ) and strengthening of the Azores-Bermuda anticyclonic circulation. Transport of East Asian aerosol is facilitated by the existence of a LLJ that extends from East Asia to the west coast of North America.

  16. Vertical Structure of Aerosols and Mineral Dust Transport Over the Bay of Bengal Using Multi-Satellite Observations.

    NASA Astrophysics Data System (ADS)

    Naduparambil Bharathan, L.

    2015-12-01

    Bay-of-Bengal (BoB), a small oceanic region Eat to Indian land mass, surrounded by heavily inhabited land masses, experiences different types of air-masses in different seasons of contrasting wind patterns, which makes it a region of large heterogeneity in the context of regional climate forcing due to atmospheric aerosols. Heterogeneity of aerosol system over the Bay of Bengal is mainly determined by three distinct source regions, which are east coast of India/central India, China/east Asia and Arabian region. Continental aerosols transported through higher elevations over BoB lead to significant impacts in regional climate by modifying the vertical thermal structure of the atmosphere and associated circulation dynamics. The study aims at a comprehensive understanding on the spatial and temporal heterogeneity of elevated aerosol over the BoB using the observations of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Being capable of short wave scattering and long wave absorption, mineral dust aerosols can affects the energetics of the atmosphere over any region.Owing to its influence on Indian monsoon rainfall and regional climate, the study aims to comprehend on the spatial and seasonal variation of mineral dust transport over the Bay of Bengal. vertical distribution of the dust extinction coefficient over the Bay of Bengal for all seasons, is derived, using a dust separation scheme that uses the depolarization measurements, a priori information on lidar ratio of dust, depolarization ratio of dust and that of non-dust aerosols. Being highly non-spherical, mineral dust significantly depolarize the radiation and possess distinct range of depolarization ratio. This property of dust is made use to identify and quantify dust over the study region. Seasonal variation of dust fraction over the Bay of Bengal is estimated seperately from CALIPSO back scattering coefficients

  17. Mapped minerals at Questa, New Mexico, using airborne visible-infrared imaging spectrometer (AVIRIS) data -- Preliminary report

    USGS Publications Warehouse

    Livo, K. Eric; Clark, Roger N.

    2002-01-01

    This preliminary study for the First Quarterly Report has spectrally mapped hydrothermally altered minerals useful in assisting in assessment of water quality of the Red River. Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) data was analyzed to characterize mined and unmined ground at Questa, New Mexico. AVIRIS data covers the Red River drainage north of the river, from between the town of Questa on the west, to east of the town of Red River. The data was calibrated and analyzed using U.S. Geological Survey custom software and spectral mineral library. AVIRIS data was tested for spectral features that matched similar features in the spectral mineral library. Goodness-of-fit and band-depth were calculated for each comparison of spectral features and used to identify surface mineralogy. Mineral distribution, mineral associations, and AVIRIS pixel spectra were examined. Mineral maps show the distribution of iron hydroxides, iron sulfates, clays, micas, carbonates, and other minerals. Initial results show a system of alteration suites that overprint each other. Quartz-sericite-pyrite (QSP) alteration grading out to propylitic alteration (epidote and calcite) was identified at the Questa Mine (molybdenum porphyry) and a similar alteration pattern was mapped at the landslide (?scar?) areas. Supergene weathering overprints the altered rock, as shown by jarosite, kaolinite, and gypsum. In the spectral analysis, hydrothermally altered ground appears to be more extensive at the unmined Goat Hill Gulch and the mined ground, than the ?scars? to the east. Though the ?scars? have similar overall altered mineral suites, there are differences between the ?scars? in sericite, kaolinite, jarosite, gypsum, and calcite abundance. Fieldwork has verified the results at the central unmined ?scar? areas.

  18. Contact freezing induced by biological (Snomax) and mineral dust (K-feldspar) particles

    NASA Astrophysics Data System (ADS)

    Hoffmann, N.; Schäfer, M.; Duft, D.; Kiselev, A. A.; Leisner, T.

    2013-12-01

    The contact freezing of supercooled cloud droplets is one of the potentially important and the least investigated heterogeneous mechanism of ice formation in tropospheric clouds [1]. On the time scales of cloud lifetime the freezing of supercooled water droplets via contact mechanism may occur at higher temperature compared to the same IN immersed in the droplet. In our experiment we study single water droplets freely levitated in an Electrodynamic Balance [2]. We have shown previously that the rate of freezing at given temperature is governed only by the rate of droplet -particle collision and by the properties of the contact ice nuclei [2, 3]. Recently, we have extended our experiments to feldspar, being the most abundant component of the atmospheric mineral dust particles, and Snomax, as a proxy for atmospheric biological Ice Nuclei (IN). In this contribution we show that both IN exhibits the same temperature, size and material dependency observed previously in immersion mode [4, 5]. Based on these results, we limit the number of mechanisms that could be responsible for the enhancement of contact nucleation of ice in supercooled water. [1] - Ladino, L. A., Stetzer, O., and Lohmann, U.: Contact freezing: a review, Atmos. Chem. Phys. Discuss., 13, 7811-7869, doi:10.5194/acpd-13-7811-2013, 2013. [2] - Hoffmann, N., Kiselev, A., Rzesanke, D., Duft, D., and Leisner, T.: Experimental quantification of contact freezing in an electrodynamic balance, Atmos. Meas. Tech. Discuss., 6, 3407-3437, doi:10.5194/amtd-6-3407-2013, 2013. [3] - Hoffmann, N., Duft, D., Kiselev, A., and Leisner, T.: Contact freezing efficiency of mineral dust aerosols studied in an electrodynamic balance: quantitative size and temperature dependence for illite particles, Faraday Discuss., doi: 10.1039/C3FD00033H, 2013. [4] - Atkinson, James D., Murray, Benjamin J., Woodhouse, Matthew T., Whale, Thomas F., Baustian, Kelly J., Carslaw, Kenneth S., Dobbie, Steven, O'Sullivan, Daniel, and Malkin, Tamsin

  19. Waveband selection within 400-4000  cm-1 of optical identification of airborne dust in coal mine tunneling face.

    PubMed

    Wang, Wenzheng; Wang, Yanming; Shi, Guoqing

    2016-04-10

    Aimed at the optical evaluation of pollution levels caused by rock dust in an underground coal mine tunneling face, the optimal detection line and optical channel were investigated. The spatial distribution of airborne rock dust under local mining and ventilation conditions was simulated by the computational fluid dynamics method; thus, combined with the scattering and absorption properties of dust particles and gas molecules, the spectral transmission characteristics of a polluted atmosphere, including dust aerosols within 400-4000  cm-1, were obtained. By eliminating the optical background of mine gases, the pure infrared signals of rock dust were further analyzed. Based on the comparison results, the detection line, which is 1.5 m high and 0.3 m away from the right wall, was determined to be the best observation position, and a waveband of 1505-1525  cm-1 was selected to estimate the dust concentration. In addition, a dual-band detection method was presented, which can simultaneously identify the dust distribution and dispersion.

  20. Combined aerosol in-situ measurements during the SALTRACE field experiment for the investigation of Saharan mineral dust microphysical and CCN properties and their spatial-temporal evolution during trans-Atlantic long-range transport

    NASA Astrophysics Data System (ADS)

    Walser, Adrian; Dollner, Maximilian; Sauer, Daniel; Weinzierl, Bernadett

    2015-04-01

    The Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE) was a field experiment conducted in June/July 2013, which aimed to investigate the transport and modification of Saharan mineral dust from the Sahara across the Atlantic Ocean to the Caribbean. In addition to ground-based measurements and satellite remote sensing, the DLR Falcon research aircraft was equipped with a number of aerosol in-situ instruments to gain direct information on the properties of airborne aerosol such as size distributions, microphysical, optical and cloud-condensation nuclei (CCN) properties. For the first time, several outbreaks of Saharan dust were probed with the same airborne instrumentation on both sides of the Atlantic. During transport, various processes may take place that modify the aerosol composition. Dry and wet deposition lead to a size-dependent aerosol removal. In case of wet deposition, the removal additionally depends on the particle's ability to act as CCN. Processes in the aqueous phase in subsequently re-evaporating cloud droplets can further alter microphysical and CCN properties of re-released particles. All resulting changes in the size distribution and particle properties impact the radiative feedback and CCN activity of the aged aerosol. This study aims to use combined airborne in-situ measurements to retrieve and compare vertically resolved aerosol size distributions, microphysical and CCN properties for both, short-range transported Saharan dust in the Cape Verde region and long-range transported dust in the Caribbean. We use this data to investigate the influence of long-range transport and associated processes on those properties. We will present vertical profiles of size-resolved aerosol concentrations and volatile fractions as well as CCN activated fractions and draw conclusions for aerosol mixing state, CCN activation diameters and particle hygroscopicities. We will discuss differences in vertical profiles and

  1. Characterization of minerals in air dust particles in the state of Tamilnadu, India through FTIR, XRD and SEM analyses

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, R.; Rajkumar, P.

    2014-11-01

    The abstract of this paper explains the presence of minerals in air which causes great concern regarding public health issues. The spectroscopic investigation of air dust particles of several samples in various locations in the state of Tamilnadu, India is reported. Qualitative analyses were carried out to determine the major and minor constituent minerals present in the samples based on the FTIR, XRD absorption peaks. This study also identified the minerals like quartz, asbestos, kaolinite, calcite, hematite, montmorillonite, nacrite and several other trace minerals in the air dust particles. The presents of quartz is mainly found in all the samples invariably. Hence the percentage of quartz and its crystalline nature were determined with the help of extinction co-efficient and crystallinity index respectively. The shape and size of the particulates are studied with SEM analysis.

  2. Ice nucleation of bare and sulfuric acid-coated mineral dust particles and implication for cloud properties

    NASA Astrophysics Data System (ADS)

    Kulkarni, Gourihar; Sanders, Cassandra; Zhang, Kai; Liu, Xiaohong; Zhao, Chun

    2014-08-01

    Ice nucleation properties of atmospherically relevant dust minerals coated with soluble materials are not yet well understood. We determined ice nucleation ability of bare and sulfuric acid-coated mineral dust particles as a function of temperature (-25 to -35°C) and relative humidity with respect to water (RHw; 75 to 110%) for five different mineral dust types: (1) Arizona test dust, (2) illite, (3) montmorillonite, (4) K-feldspar, and (5) quartz. The particles were dry dispersed and size selected at 200 nm, and we determined the fraction of dust particles nucleating ice at various temperatures and RHw. Under water-subsaturated conditions, compared to bare dust particles, we found that coated particles showed a reduction in their ice nucleation ability. Under water-supersaturated conditions, however, we did not observe a significant coating effect (i.e., the bare and coated dust particles had nearly similar nucleating properties). X-ray diffraction patterns of the coated particles indicated that acid treatment altered the crystalline nature of the surface and caused structural disorder; thus, we concluded that the lack of such structured order reduced the ice nucleation efficiency of the coated particles in deposition ice nucleation mode. In addition, our single column model results show that coated particles significantly modify cloud properties such as ice crystal number concentration and ice water content compared to bare particles in water-subsaturated conditions. However, in water-supersaturated conditions, cloud properties differ only at warmer temperatures. These modeling results imply that future aged dust particle simulations should implement coating parameterizations to accurately predict cloud properties.

  3. Mass specific optical absorption coefficients of mineral dust components measured by a multi wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2014-09-01

    Mass specific optical absorption coefficients of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at wavelengths of 1064, 532, 355 and 266 nm. These values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. These results are expected to have considerable importance in global radiative forcing calculations. They can also serve as reference for validating calculated wavelength dependent imaginary parts (κ) of complex refractive indices which up to now have been typically deduced from bulk phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk phase measurements.

  4. Mineral dust and NOx promote the conversion of SO2 to sulfate in heavy pollution days

    PubMed Central

    He, Hong; Wang, Yuesi; Ma, Qingxin; Ma, Jinzhu; Chu, Biwu; Ji, Dongsheng; Tang, Guiqian; Liu, Chang; Zhang, Hongxing; Hao, Jiming

    2014-01-01

    Haze in China has been increasing in frequency of occurrence as well as the area of the affected region. Here, we report on a new mechanism of haze formation, in which coexistence with NOx can reduce the environmental capacity for SO2, leading to rapid conversion of SO2 to sulfate because NO2 and SO2 have a synergistic effect when they react on the surface of mineral dust. Monitoring data from five severe haze episodes in January of 2013 in the Beijing-Tianjin-Hebei regions agreed very well with the laboratory simulation. The combined air pollution of motor vehicle exhaust and coal-fired flue gases greatly reduced the atmospheric environmental capacity for SO2, and the formation of sulfate was found to be a main reason for the growth of fine particles, which led to the occurrence of haze. These results indicate that the impact of motor vehicle exhaust on the atmospheric environment might be underestimated. PMID:24566871

  5. Pulmonary mineral dust. A study of ninety patients by electron microscopy, electron microanalysis, and electron microdiffraction.

    PubMed Central

    Berry, J. P.; Henoc, P.; Galle, P.; Pariente, R.

    1976-01-01

    The results of a study of 90 patients are presented. Intrapulmonary mineral deposits were characterized by electron diffraction and electron probe microanalysis. Using this method, pneumoconioses may be distinguidhed from other pneumopathies. In cases of pneumoconiosis, there exists a specific relationship between the etiology of the dust exposure and the crystallographic characteristics of the intrapulmonary deposits. The nature of the deposits may be indicative of a specific type of pneumoconiosis. This method is particularly useful in differentiating between asbestos bodies and ferruginous bodies. The value of the method in general and its importance in the study of pneumoconiosis are discussed. Images Figure 4 Figure 13 Figure 5 Figure 14 Figure 6 Figure 15 Figure 7 Figure 16 Figure 8 Figure 17 Figure 1 Figure 9 Figure 10 Figure 2 Figure 11 Figure 3 Figure 12 PMID:937507

  6. The immersion freezing behavior of mixtures of mineral dust and biological substances

    NASA Astrophysics Data System (ADS)

    Augustin, Stefanie; Schneider, Johannes; Schmidt, Susan; Niedermeier, Dennis; Ebert, Martin; Voigtländer, Jens; Rösch, Michael; Stratmann, Frank; Wex, Heike

    2014-05-01

    Biological particles such as bacteria or pollen are known to be efficient ice nuclei. It is also known that ice nucleating active (INA) macromolecules, i.e. protein complexes in the case of bacteria (e.g. Wolber et al., 1986), and most likely polysaccharides in the case of pollen (Pummer et al., 2012) are responsible for the freezing. Very recently it was suggested that these INA macromolecules maintain their nucleating ability even when they are separated from their original carriers (Hartmann et al., 2013; Augustin et al., 2013). This opens the possibility of accumulation of such INA macromolecules in e.g. soils and the resulting particles could be an internal mixture of mineral dust and INA macromolecules. If such biological IN containing soil particles are then dispersed into the atmosphere due to e.g. wind erosion or agricultural processes they could induce ice nucleation at temperatures higher than -20°C. To explore this hypothesis, we performed a measurement campaign within the research unit INUIT, where we investigated the ice nucleation behavior of mineral dust particles internally mixed with INA macromolecules. Specifically, we mixed pure mineral dust (illite) with INA biological material (SNOMAX and birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). To characterize the mixing state of the produced aerosol we used single mass spectrometry as well as electron microscopy. We found that internally mixed particles which containing ice active biological material show the same ice nucleation behavior as the purely biological particles. That shows that INA macromolecules which are located on a mineral dust particle dominate the freezing process. Acknowledgement: Part of this work was done within the framework of the DFG funded Ice Nucleation research UnIT (INUIT, FOR 1525) under WE 4722/1-1. Augustin, S., Hartmann, S., Pummer, B., Grothe, H

  7. Analysis and differentiation of mineral dust by single particle laser mass spectrometry

    SciTech Connect

    Gallavardin, S. J.; Lohmann, U.; Cziczo, Daniel J.

    2008-05-09

    Abstract This study evaluates the potential of single particle laser desorption/ionization mass spectrometry for the analysis of atmospherically relevant mineral dusts. Samples of hematite, goethite, calcium carbonate, calcium sulfate, silica, quartz, montmorrillonite, kaolinite, illite, hectorite, wollastonite and nephelinsyenit were investigated in positive and negative ion mode with a monopolar time-of-flight mass spectrometer where the desorption/ionization step was performed with a 193 nm excimer laser (~109 W/cm2). Particle size ranged from 500 nm to 3 μm. Positive mass spectra mainly provide elemental composition whereas negative ion spectra provide information on element speciation and of a structural nature. The iron oxide, calcium-rich and aluminosilicate nature of particles is established in positive ion mode. The differentiation of calcium materials strongly relies on the calcium counter-ions in negative mass spectra. Aluminosilicates can be differentiated in both positive and negative ion mode using the relative abundance of various aluminum and silicon ions.

  8. Particle Size Distribution of Airborne Microorganisms and Pathogens during an Intense African Dust Event in the Eastern Mediterranean

    PubMed Central

    Polymenakou, Paraskevi N.; Mandalakis, Manolis; Stephanou, Euripides G.; Tselepides, Anastasios

    2008-01-01

    Background The distribution of microorganisms, and especially pathogens, over airborne particles of different sizes has been ignored to a large extent, but it could have significant implications regarding the dispersion of these microorganisms across the planet, thus affecting human health. Objectives We examined the microbial quality of the aerosols over the eastern Mediterranean region during an African storm to determine the size distribution of microorganisms in the air. Methods We used a five-stage cascade impactor for bioaerosol collection in a coastal city on the eastern Mediterranean Sea during a north African dust storm. Bacterial communities associated with aerosol particles of six different size ranges were characterized following molecular culture–independent methods, regardless of the cell culturability (analysis of 16S rRNA genes). Results All 16S rDNA clone libraries were diverse, including sequences commonly found in soil and marine ecosystems. Spore-forming bacteria such as Firmicutes dominated large particle sizes (> 3.3 μm), whereas clones affiliated with Actinobacteria (found commonly in soil) and Bacteroidetes (widely distributed in the environment) gradually increased their abundance in aerosol particles of reduced size (< 3.3 μm). A large portion of the clones detected at respiratory particle sizes (< 3.3 μm) were phylogenetic neighbors to human pathogens that have been linked to several diseases. Conclusions The presence of aerosolized bacteria in small size particles may have significant implications to human health via intercontinental transportation of pathogens. PMID:18335093

  9. Seasonal variations of snow chemistry and mineral dust in the snow pit at GV7, Antarctica

    NASA Astrophysics Data System (ADS)

    Kang, Jung-Ho; Hwang, Heejin; Han, Yongchoul; Hong, Sang Bum; Lee, Khanghyun; Do Hur, Soon; Frezzotti, Massimo; Narcisi, Biancamaria

    2015-04-01

    We conducted the scientific ice coring project led by PNRA and KOPRI during the 2013/2014 Italian-Korean Antarctic Expedition in the framework of International Partnerships in Ice Core Science (IPICS) to understand the climatic variability in the last 2000 years. In the part of project, we collected a 3.0 m-depth snow pit at the site of GV7 (S 70° 41'17.1", E 158° 51'48.9", 1950 m a.s.l.), Antarctica. Here, we present the results obtained from the analysis of the water isotope compositions, the major ion concentrations, and the mineral dust concentrations from the snow pit. Snow densities and temperatures also measured in the field. At KOPRI, the samples were melted, then the stable water isotopes, major ions, and particle size distribution were analyzed with the cavity ring-down spectrometers (L1102-i, Piccaro), ion chromatography (ICS-2100, Thermo), and coulter counter (Multisizer 3, Beckman Coulter), respectively. The δ18O varies between -38.3 and -24.1o with a mean value of -31.0o. The δD ranges between -331 and -186o with a mean value of -243o. Among the ion concentrations (Na+, Ca2+, Mg2+, Cl-, SO42-, CH3SO3-(MSA)) from the snow pit, MSA concentrations show a clear seasonal variation. The mineral dust in the pit characterized with the differences of the concentration and the particle size distribution by the seasonality. These data allow us to assume about 4.5 years of snow deposition covered from 2009 to 2013 by these oscillations of the isotopes and geochemical characteristics.

  10. Knudsen cell and smog chamber study of the heterogeneous uptake of sulfur dioxide on Chinese mineral dust.

    PubMed

    Zhou, Li; Wang, Weigang; Gai, Yanbo; Ge, Maofa

    2014-12-01

    The heterogeneous uptake processes of sulfur dioxide on two types of Chinese mineral dust (Inner Mongolia desert dust and Xinjiang sierozem) were investigated using both Knudsen cell and smog chamber system. The temperature dependence of the uptake coefficients was studied over a range from 253 to 313 K using the Knudsen cell reactor, the initial uptake coefficients decreased with the increasing of temperature for these two mineral dust samples, whereas the steady state uptake coefficients of the Xinjiang sierozem increased with the temperature increasing, and these temperature dependence functions were obtained for the first time. In the smog chamber experiments at room temperature, the steady state uptake coefficients of SO2 decreased evidently with the increasing of sulfur dioxide initial concentration from 1.72 × 10¹² to 6.15 × 10¹² mol/cm³. Humid air had effect on the steady state uptake coefficients of SO₂onto Inner Mongolia desert dust. Consequences about the understanding of the uptake processes onto mineral dust samples and the environmental implication were also discussed.

  11. Knudsen cell and smog chamber study of the heterogeneous uptake of sulfur dioxide on Chinese mineral dust.

    PubMed

    Zhou, Li; Wang, Weigang; Gai, Yanbo; Ge, Maofa

    2014-12-01

    The heterogeneous uptake processes of sulfur dioxide on two types of Chinese mineral dust (Inner Mongolia desert dust and Xinjiang sierozem) were investigated using both Knudsen cell and smog chamber system. The temperature dependence of the uptake coefficients was studied over a range from 253 to 313 K using the Knudsen cell reactor, the initial uptake coefficients decreased with the increasing of temperature for these two mineral dust samples, whereas the steady state uptake coefficients of the Xinjiang sierozem increased with the temperature increasing, and these temperature dependence functions were obtained for the first time. In the smog chamber experiments at room temperature, the steady state uptake coefficients of SO2 decreased evidently with the increasing of sulfur dioxide initial concentration from 1.72 × 10¹² to 6.15 × 10¹² mol/cm³. Humid air had effect on the steady state uptake coefficients of SO₂onto Inner Mongolia desert dust. Consequences about the understanding of the uptake processes onto mineral dust samples and the environmental implication were also discussed. PMID:25499490

  12. Natural Airborne Dust and Heavy Metals: A Case Study for Kermanshah, Western Iran (2005–2011)

    PubMed Central

    PIRSAHEB, Meghdad; ZINATIZADEH, Aliakbar; KHOSRAVI, Touba; ATAFAR, Zahra; DEZFULINEZHAD, Saeed

    2014-01-01

    Abstract Background Dust pollution has become a serious environmental problem especially in recent decades. The present study aim was the investigation of the levels of PM10 concentration in Kermanshah, western Iran and also measured five important heavy metals (Pb, Cd, As, Hg and Cr) in some samples during 2005 to 2011. Methods A total 2277 samples were collected from air pollution measurement station belonging to the Department of Environment in Kermanshah. Furthermore, four samples were collected during dusty days to determine the selected heavy metals concentration. The samples were analyzed statistically using the SPSS Ver.16 Results The highest seasonal average concentration in spring was recorded in 2008 with 216.63μg/m3, and the maximum values of 267.79 and 249.09μg/m3 were observed in summer and winter in 2009, respectively. The maximum concentration of 127.1μg/m3 was in autumn in 2010. The metals concentration (Pb, Cd, As, Hg and Cr) of samples were 42.32±5.40, 37.45±9.29, 3.51±2.07, 1.88±1.64 and 0μg/g in July, 2009, respectively. Conclusion According to National Ambient Air Quality of USEPA guidelines, the most days with non-standard, warning, emergency and critical conditions were related to 2009 (120 days) while the least polluted days were recorded in 2006 (16 days). There are concerns about the increasing frequency and intensity trend of dust storms in recent years as a result of special condition in neighboring Western countries which it could endanger public health and environment. All measured heavy metals except mercury was higher than the standard level of WHO and USEPA. PMID:26005656

  13. An investigation into the relationship between coal workers' pneumoconiosis and dust exposure in U. S. coal miners

    SciTech Connect

    Attfield, M.D.; Morring, K. )

    1992-08-01

    The National Study of Coal Workers' Pneumoconiosis (NSCWP) is a large, continuing epidemiologic study of the respiratory health of U.S. coal miners. By using information from the study, prevalence of coal workers' pneumoconiosis (CWP) was related to indexes of dust exposure obtained from research and compliance sampling data. Clear relationships between prevalences of both simple CWP and progressive massive fibrosis (PMF) and estimated dust exposure were seen. Additional effects independently associated with coal rank (% carbon) and age were also seen. Logistic model fitting indicated that between 2% and 12% of miners exposed to a 2-mg/m3 dust environment in bituminous coal mines would be expected to have Category 2 or greater CWP after a 40-yr working life; PMF would be expected for between 1.3% and 6.7%. The risks for anthracite miners appeared to be greater. There was a suggestion of a background level of abnormality, not associated with dust exposure, but increasing with age. Although there are certain weaknesses in the data used to derive these exposure estimates, the results are in general agreement with, but somewhat greater than, some recent findings for British coal miners.

  14. Modelling direct radiative effect of mineral dust with the NMMB/BSC-CTM for dust outbreak events over the Mediterranean in summer 2012

    NASA Astrophysics Data System (ADS)

    Obiso, Vincezo; Jorba, Oriol; Basart, Sara; Baldasano, Jose M.; Nabat, Pierre

    2014-05-01

    Aerosols interact with the atmospheric system scattering and absorbing solar radiation, with a significant impact on atmospheric energy and hydrologic processes. Radiative forcing associated with these perturbations affects climate and meteorology. In this contribution, we analyse model results of the Direct Radiative Effect (DRE) of mineral dust over the western-Mediterranean during summer 2012. For that, the NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM) is applied on a regional domain at 0.1º horizontal resolution. The NMMB/BSC-CTM is a new on-line chemical weather prediction system coupling atmospheric and chemistry processes. In the radiation module of the model mineral dust is treated as a radiatively active substance interacting both short and longwave radiation. The impact of the mineral dust outbreaks on meteorology is discussed by comparing model forecasts with atmospheric analysis and meteorological observations. The analysis focuses in the vertical structure of the atmosphere and the resulting surface meteorological conditions. The authors acknowledge the support from the grant SEV-2011-00067 of Severo Ochoa Program, awarded by the Spanish Government.

  15. Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

    USGS Publications Warehouse

    Crowley, J.K.; Brickey, D.W.; Rowan, L.C.

    1989-01-01

    Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.

  16. Mapping Weathering and Alteration Minerals in the Comstock and Geiger Grade Areas using Visible to Thermal Infrared Airborne Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Vaughan, Greg R.; Calvin, Wendy M.

    2005-01-01

    To support research into both precious metal exploration and environmental site characterization a combination of high spatial/spectral resolution airborne visible, near infrared, short wave infrared (VNIR/SWIR) and thermal infrared (TIR) image data were acquired to remotely map hydrothermal alteration minerals around the Geiger Grade and Comstock alteration regions, and map the mineral by-products of weathered mine dumps in Virginia City. Remote sensing data from the Airborne Visible Infrared Imaging Spectrometer (AVIRIS), SpecTIR Corporation's airborne hyperspectral imager (HyperSpecTIR), the MODIS-ASTER airborne simulator (MASTER), and the Spatially Enhanced Broadband Array Spectrograph System (SEBASS) were acquired and processed into mineral maps based on the unique spectral signatures of image pixels. VNIR/SWIR and TIR field spectrometer data were collected for both calibration and validation of the remote data sets, and field sampling, laboratory spectral analyses and XRD analyses were made to corroborate the surface mineralogy identified by spectroscopy. The resulting mineral maps show the spatial distribution of several important alteration minerals around each study area including alunite, quartz, pyrophyllite, kaolinite, montmorillonite/muscovite, and chlorite. In the Comstock region the mineral maps show acid-sulfate alteration, widespread propylitic alteration and extensive faulting that offsets the acid-sulfate areas, in contrast to the larger, dominantly acid-sulfate alteration exposed along Geiger Grade. Also, different mineral zones within the intense acid-sulfate areas were mapped. In the Virginia City historic mining district the important weathering minerals mapped include hematite, goethite, jarosite and hydrous sulfate minerals (hexahydrite, alunogen and gypsum) located on mine dumps. Sulfate minerals indicate acidic water forming in the mine dump environment. While there is not an immediate threat to the community, there are clearly sources of

  17. Mineral carbonation for carbon sequestration in cement kiln dust from waste piles.

    PubMed

    Huntzinger, Deborah N; Gierke, John S; Sutter, Lawrence L; Kawatra, S Komar; Eisele, Timothy C

    2009-08-30

    Alkaline earth metals, such as calcium and magnesium oxides, readily react with carbon dioxide (CO(2)) to produce stable carbonate minerals. Carbon sequestration through the formation of carbonate minerals is a potential means to reduce CO(2) emissions. Calcium-rich, industrial solid wastes and residues provide a potential source of highly reactive oxides, without the need for pre-processing. This paper presents the first study examining the feasibility of carbon sequestration in cement kiln dust (CKD), a byproduct generated during the manufacturing of cement. A series of column experiments were conducted on segments of intact core taken from landfilled CKD. Based on stoichiometry and measured consumption of CO(2) during the experiments, degrees of carbonation greater than 70% of the material's potential theoretical extent were achieved under ambient temperature and pressure conditions. The overall extent of carbonation/sequestration was greater in columns with lower water contents. The major sequestration product appears to be calcite; however, more detailed material characterization is need on pre- and post-carbonated samples to better elucidate carbonation pathways and products.

  18. Mineral dust events over the Mediterranean: Multi-platform characterization and comparison with GEOS-Chem simulation

    NASA Astrophysics Data System (ADS)

    Bartlett, K. S.; Luo, G.; Yu, F.; Aerosol Microphysics Research Group

    2011-12-01

    Kevin S. Bartlett, Gan Luo, and Fangqun Yu Atmospheric Sciences Research Center, State University of New York, 251 Fuller Road, Albany, New York 12203, USA Abstract. The Mediterranean Basin (MB) has a population of 210 million with approximately 50% living within the eastern half of the MB where seasonal lows tracking southeastward across Italy transport climate impacting, visibility and air quality reducing mineral dust from North African deserts. Located 1000 km NE of African dust and 400 km SE of Greek population centers, Crete is uniquely located at a crossroads of the seasonal storm track and a mineral dust pathway recording some of the highest average AODs within the region, and is well instrumented to observe this trend. Investigating dust transport using NCEP reanalysis data, surface based METAR, AERONET and SMPS as well as space based MODIS, MISR and CALIPSO observations coupled with nested GEOS-Chem-APM simulations, this study exploits sensor strengths while noting weaknesses to characterize seasonal trends and individual dust events. To verify seasonal trends, METAR, AERONET and NCEP data were collected over Crete from 2003-2010. This 8 year period showed that the majority of large aerosol events occurred during late winter and early spring during passage of transitional low pressure systems. During 2009, newly released, SMPS particle size distribution measurements were acquired from Finokalia. These in situ measurements coupled with the observation collective were key to confirming dust events and for comparing the nested GEOS-Chem's particle size distribution and AOD simulations, which showed some skill capturing dust events as well as the seasonal dust peaks early in the year. In this study we exploited the strengths of the observation collective and model runs to prove seasonal North African dust transport across Crete. We also noted the limitations of surface based: point observations, limited to localized conditions of transport and fallout, where

  19. Variations on morphology and elemental composition of mineral dust particles from local, regional, and long-range transport meteorological scenarios

    NASA Astrophysics Data System (ADS)

    Coz, Esther; Gómez-Moreno, Francisco J.; Casuccio, Gary S.; ArtíñAno, BegoñA.

    2010-06-01

    Mineral dust is the second major source of PM10 in Madrid, reaching up to 80% of the PM10 mass during certain long-range dust transport events. Three different types of scenarios have been found to be associated with the high particle concentration episodes in the city: local anthropogenic, regional recirculation, and African dust transport processes. The present study focuses on the characterization of the individual mineral dust particles related to some chemical and morphological features during these three types of episodes, with special attention to local and regional episodes. To achieve this purpose, four different samples were selectively collected during the 2004-2005 period campaigns, one corresponding to each type of scenario and other sample from an Atlantic ventilated one. Meteorological situation, dust source identification, impact on ambient concentrations, size range distribution, and particle individual analysis have been characterized for each of them. Elemental composition and morphology of more than 30,000 mineral particles were analyzed by computer-controlled scanning electron microscopy. Particles were grouped into clusters based on their elemental composition, and the aspect ratio (AR) of each cluster or category was compared for each type of episode. The AR was related to the mineralogical crystal structure of each chemical cluster. The dates chosen for microscopy analysis were in good agreement in size distribution and chemical composition with the average of the dates in the entire campaign and with those from previous campaigns. Major differences between local/regional and long-range transported mineral dust were found in the relative abundance between carbonates and silicates, with much higher abundance of calcium carbonates in the first ones. These differences between silicate and carbonate contents were consistent with the results found in previous campaigns and were directly related to the composition of the parent topsoil by studying

  20. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE PAGES

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2014-06-27

    Data from both laboratory studies and atmospheric measurements are used to develop a simple parametric description for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken to approximate the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developedmore » follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A correction factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this correction factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization to the immersion

  1. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE PAGES

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2015-01-13

    Data from both laboratory studies and atmospheric measurements are used to develop an empirical parameterization for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken as a measure of the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterizationmore » developed follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A calibration factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this calibration factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization, including calibration

  2. Endotoxin levels in settled airborne dust in European schools: the HITEA school study.

    PubMed

    Jacobs, J H; Krop, E J M; Borras-Santos, A; Zock, J-P; Taubel, M; Hyvarinnen, A; Pekkanen, J; Doekes, G; Heederik, D J J

    2014-04-01

    Indoor exposure to microbial agents is known to influence respiratory health. Besides home exposure, exposure in schools can affect respiratory health. In this study, we measured endotoxin in settled dust in primary schools in three European countries from three different geographical regions with different climates. Our aim was to characterize endotoxin levels in primary schools and evaluate associations with potential determinants. Endotoxin levels were repeatedly assessed in 23 schools in Spain (n = 7), the Netherlands (n = 10), and Finland (n = 6) using electrostatic dustfall collectors. In total, 645 measurements were taken in 237 classrooms. Endotoxin levels differed significantly between countries; Dutch schools had the highest levels, while Finnish schools showed the lowest levels. In each country, differences in endotoxin levels were observed between schools and over the sampling periods. Estimates improved after adjustment for sampling period. Factors affecting endotoxin levels in a school differed per country. In general, endotoxin levels were higher in lower grades and in classrooms with higher occupancy. School endotoxin levels may contribute significantly to total endotoxin exposure in children and teachers. As the correlation between the repeated measurements is reasonable, single endotoxin measurements form a reasonable basis for estimating annual endotoxin levels in schools.

  3. Airborne Fungi in Sahara Dust Aerosols Reaching the Eastern Caribbean: II. Species Identification Using Molecular Techniques

    NASA Astrophysics Data System (ADS)

    de La Mota, A.; Betancourt, C.; Detres, Y.; Armstrong, R.

    2003-12-01

    Fungi samples from filters collected in Castle Bruce, Dominica from March through July 2002, were previously purified and identified to genus level using classic macroscopic and microscopic techniques. A total of 105 isolated colonies were cultured in liquid media and the mycelial mats used for DNA extraction. PCR was used to amplify the ITS region of the rDNA using the ITS1 and ITS4 primers. Both strands of the amplified products were sequenced and the final identification to species level was completed by a GenBank search. Fourteen different species and one fungal endophyte were identified from genders Aspergillus,Penicillium, Fusarium, Cladosporium, Curvularia and Phanerochaete. Some of these species such as A. fumigatus, A. japonicus, P. citrinum and C. cladosporoides are known to cause respiratory disorders in humans. A. fumigatus causes an aggressive pulmonary allergic response that might result in allergic bronchopulmonary aspergillosis. Other species such as F. equiseti and C. brachyspora are plant pathogens affecting economically important crops. Sahara dust is an important source of fungal spores of species that are not common in the Caribbean region.

  4. Airborne Fungi in Sahara Dust Aerosols Reaching the Eastern Caribbean: I. Taxonomic Characterization by Morphological Features

    NASA Astrophysics Data System (ADS)

    Rivera-Denizard, O.; Betancourt, C.; Armstrong, R. A.; Detres, Y.

    2003-12-01

    A wide variety of microorganisms are dispersed into the Caribbean region due to the input of Saharan dust aerosols during the summer months. These microorganisms can cause diseases in plants and animals, and might be responsible for an increase incidence of asthma and respiratory diseases in this region. A PM 2.5 air sampling station was installed in Castle Bruce, Dominica from March through July of 2002. Fourteen filters were obtained by running the air sampler continuously for 24 hour periods. The samples were collected in sterile Teflon filters (47 mm in diameter, 0.2 um pore size), inoculated in Malt Extract Agar (MEA) with lactic acid and incubated at 29° C. Colonies were counted, isolated and cultured on separate Petri dishes. Fungal classification to the genus level used macroscopic features and microscopic evaluation. The Nomarski light microscopy technique was used for identification of reproductive structures. A total of 105 colonies were isolated. Six genera including Aspergillus, Penicillium, Cladosporium, Fusarium, Curvularia,and Nigrospora were identified. The protocol for the molecular characterization to species level is presented as the second part of this work.

  5. On realistic size equivalence and shape of spheroidal Saharan mineral dust particles applied in solar and thermal radiative transfer calculations

    NASA Astrophysics Data System (ADS)

    Otto, S.; Trautmann, T.; Wendisch, M.

    2010-11-01

    Realistic size equivalence and shape of Saharan mineral dust particles are derived from on in-situ particle, lidar and sun photometer measurements during SAMUM-1 in Morocco (19 May 2006), dealing with measured size- and altitude-resolved axis ratio distributions of assumed spheroidal model particles. The data were applied in optical property, radiative effect, forcing and heating effect simulations to quantify the realistic impact of particle non-sphericity. It turned out that volume-to-surface equivalent spheroids with prolate shape are most realistic: particle non-sphericity only slightly affects single scattering albedo and asymmetry parameter but may enhance extinction coefficient by up to 10%. At the bottom of the atmosphere (BOA) the Saharan mineral dust always leads to a loss of solar radiation, while the sign of the forcing at the top of the atmosphere (TOA) depends on surface albedo: solar cooling/warming over a mean ocean/land surface. In the thermal spectral range the dust inhibits the emission of radiation to space and warms the BOA. The most realistic case of particle non-sphericity causes changes of total (solar plus thermal) forcing by 55/5% at the TOA over ocean/land and 15% at the BOA over both land and ocean and enhances total radiative heating within the dust plume by up to 20%. Large dust particles significantly contribute to all the radiative effects reported.

  6. Predicting the mineral composition of dust aerosols - Part 2: Model evaluation and identification of key processes with observations

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Pérez García-Pando, C.; Miller, R. L.

    2015-10-01

    A global compilation of nearly sixty measurement studies is used to evaluate two methods of simulating the mineral composition of dust aerosols in an Earth system model. Both methods are based upon a Mean Mineralogical Table (MMT) that relates the soil mineral fractions to a global atlas of arid soil type. The Soil Mineral Fraction (SMF) method assumes that the aerosol mineral fractions match the fractions of the soil. The MMT is based upon soil measurements after wet sieving, a process that destroys aggregates of soil particles that would have been emitted from the original, undisturbed soil. The second method approximately reconstructs the emitted aggregates. This model is referred to as the Aerosol Mineral Fraction (AMF) method because the mineral fractions of the aerosols differ from those of the wet-sieved parent soil, partly due to reaggregation. The AMF method remedies some of the deficiencies of the SMF method in comparison to observations. Only the AMF method exhibits phyllosilicate mass at silt sizes, where they are abundant according to observations. In addition, the AMF quartz fraction of silt particles is in better agreement with measured values, in contrast to the overestimated SMF fraction. Measurements at distinct clay and silt particle sizes are shown to be more useful for evaluation of the models, in contrast to the sum over all particles sizes that is susceptible to compensating errors, as illustrated by the SMF experiment. Model errors suggest that allocation of the emitted silt fraction of each mineral into the corresponding transported size categories is an important remaining source of uncertainty. Evaluation of both models and the MMT is hindered by the limited number of size-resolved measurements of mineral content that sparsely sample aerosols from the major dust sources. The importance of climate processes dependent upon aerosol mineral composition shows the need for global and routine mineral measurements.

  7. Predicting the Mineral Composition of Dust Aerosols. Part 2; Model Evaluation and Identification of Key Processes with Observations

    NASA Technical Reports Server (NTRS)

    Perlwitz, J. P.; Garcia-Pando, C. Perez; Miller, R. L.

    2015-01-01

    A global compilation of nearly sixty measurement studies is used to evaluate two methods of simulating the mineral composition of dust aerosols in an Earth system model. Both methods are based upon a Mean Mineralogical Table (MMT) that relates the soil mineral fractions to a global atlas of arid soil type. The Soil Mineral Fraction (SMF) method assumes that the aerosol mineral fractions match the fractions of the soil. The MMT is based upon soil measurements after wet sieving, a process that destroys aggregates of soil particles that would have been emitted from the original, undisturbed soil. The second method approximately reconstructs the emitted aggregates. This model is referred to as the Aerosol Mineral Fraction (AMF) method because the mineral fractions of the aerosols differ from those of the wet-sieved parent soil, partly due to reaggregation. The AMF method remedies some of the deficiencies of the SMF method in comparison to observations. Only the AMF method exhibits phyllosilicate mass at silt sizes, where they are abundant according to observations. In addition, the AMF quartz fraction of silt particles is in better agreement with measured values, in contrast to the overestimated SMF fraction. Measurements at distinct clay and silt particle sizes are shown to be more useful for evaluation of the models, in contrast to the sum over all particles sizes that is susceptible to compensating errors, as illustrated by the SMF experiment. Model errors suggest that allocation of the emitted silt fraction of each mineral into the corresponding transported size categories is an important remaining source of uncertainty. Evaluation of both models and the MMT is hindered by the limited number of size-resolved measurements of mineral content that sparsely sample aerosols from the major dust sources. The importance of climate processes dependent upon aerosol mineral composition shows the need for global and routine mineral measurements.

  8. Predicting the mineral composition of dust aerosols - Part 2: Model evaluation and identification of key processes with observations

    NASA Astrophysics Data System (ADS)

    Perlwitz, J. P.; Pérez García-Pando, C.; Miller, R. L.

    2015-02-01

    A global compilation from nearly sixty measurement studies is used to evaluate two methods of simulating the mineral composition of dust aerosols in an Earth system model. Both methods are based upon a Mean Mineralogical Table (MMT) that relates the soil mineral fractions to a global atlas of arid soil type. The Soil Mineral Fraction (SMF) method assumes that the aerosol mineral fractions match those of the soil. The MMT is based upon soil measurements after wet sieving, where soil aggregates are broken into smaller particles. The second method approximately reconstructs the aggregates and size distribution of the original soil that is subject to wind erosion. This model is referred to as the Aerosol Mineral Fraction (AMF) method because the mineral fractions of the aerosols differ from those of the wet-sieved parent soil, partly due to reaggregation. The AMF method remedies some of the deficiencies of the SMF method in comparison to observation. Only the AMF method restores phyllosilicate mass to silt sizes, where they are abundant according to observations. In addition, the AMF quartz fraction of silt particles is in closer agreement with measured values, in contrast to the overestimated SMF fraction. Measurements at separate clay and silt particle sizes are shown to be more useful for evaluation of the models, compared to the sum over all particles sizes that is susceptible to compensating errors in the SMF experiment. Model errors suggest that apportionment of the emitted silt fraction of each mineral into the corresponding transported size categories is an important remaining uncertainty. Substantial uncertainty remains in evaluating both models and the MMT due to the limited number of size-resolved measurements of mineral content that sparsely sample aerosols from the major dust sources. The importance of climate processes dependent upon aerosol mineral composition shows the need for global and routine mineral measurements.

  9. Atmospheric transport of mineral dust from the Indo-Gangetic Plain: Temporal variability, acid processing, and iron solubility

    NASA Astrophysics Data System (ADS)

    Srinivas, Bikkina; Sarin, M. M.; Rengarajan, R.

    2014-08-01

    transport of chemical constituents from the Indo-Gangetic Plain (IGP) to the Bay of Bengal is a conspicuous seasonal feature that occurs during the late NE-monsoon (December-March). With this perspective, aerosol composition and abundance of mineral dust have been studied during November 2009 to March 2010 from a sampling site (Kharagpur: 22.3°N, 87.3°E) in the IGP, representing the atmospheric outflow to the Bay of Bengal. The chemical composition of PM2.5 suggests the dominance of nss-SO42- (6.9-24.3 µg m-3); whereas the abundance of mineral dust varied from 3 to 18 µg m-3. The concentration of aerosol iron (FeTot) and its fractional solubility (Fews % = Fews/FeTot *100, where Fews is the water-soluble fraction of FeTot) varied from 60 to 1144 ng m-3 and from 6.7 to 26.5%, respectively. A striking similarity in the temporal variability of total inorganic acidity (TIA = NO3- + nss-SO42-) and Fews (%) provides evidence for acid processing of mineral dust (alluvium) during atmospheric transport from the IGP. The contribution of TIA to water-soluble inorganic species [(nss-SO42- + NO3-)/ΣWSIS], mass ratios of Ca/Al and Fe/Al, and abundance of dust (%) and Fews (%) in the IGP-outflow are similar to the aerosol composition over the Bay of Bengal. With the rapid increase in anthropogenic activities over south and south-east Asia, the enhanced fractional solubility of aerosol iron (attributed to acid processing of mineral dust) has implications to further increase in the air-sea deposition of Fe to the Ocean surface.

  10. Parameterization of heterogeneous ice nucleation on mineral dust particles: An application in a regional scale model

    NASA Astrophysics Data System (ADS)

    Niemand, M.; Vogel, B.; Vogel, H.; Connolly, P.; Klein, H.; Bingemer, H.; Hoose, C.; Moehler, O.; Leisner, T.

    2010-12-01

    In climate and weather models, the quantitative description of aerosol and cloud processes relies on simplified assumptions. This contributes major uncertainties to the prediction of global and regional climate change. The parameterization of heterogeneous ice nucleation is a step towards improving our current knowledge of the importance of the cloud ice phase in weather and climate models and can aid in the theoretical understanding of such processes. This contribution presents a new parameterization derived from a large number of experiments carried out at the aerosol and cloud chamber facility AIDA [1] of Karlsruhe Institute of Technology. AIDA is especially suitable to study ice nucleation processes at tropospheric and stratospheric cloud conditions covering a wide range of temperature and pressure. During pumping expansion, cooling rates between -0.3 and -5.0 K/min, equating to vertical wind velocities of 0.5 to 8 m/s, and a relative humidity range of up to more than 200% with respect to ice can be reached. The parameterization is valid for the temperature range -35°C to -15°C. In order to derive and test the parameterization a parameter called the ice-active surface site density was calculated for a number of different experiments with mineral dust acting as ice nuclei in the immersion and/or deposition mode. An exponential function was fitted to this data of ice-active surface site density vs. temperature. The curve fit was then used within the bin microphysical model ACPIM [2] to simulate the ice formation rates from the experiments. The major dust outbreak over the Sahara in May 2008 which was followed by a dust transport over the Mediterranean and Western Europe was simulated using the regional scale online coupled model system COSMO-ART (Vogel et al., 2009). Based on the model results the exponential curve fit was used to calculate the ice nuclei number concentration at Kleiner Feldberg (Germany). The results will be compared to measurements from

  11. A stable downward continuation of airborne magnetic data: A case study for mineral prospectivity mapping in Central Iran

    NASA Astrophysics Data System (ADS)

    Abedi, Maysam; Gholami, Ali; Norouzi, Gholam-Hossain

    2013-03-01

    Previous studies have shown that a well-known multi-criteria decision making (MCDM) technique called Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE II) to explore porphyry copper deposits can prioritize the ground-based exploratory evidential layers effectively. In this paper, the PROMETHEE II method is applied to airborne geophysical (potassium radiometry and magnetometry) data, geological layers (fault and host rock zones), and various extracted alteration layers from remote sensing images. The central Iranian volcanic-sedimentary belt is chosen for this study. A stable downward continuation method as an inverse problem in the Fourier domain using Tikhonov and edge-preserving regularizations is proposed to enhance magnetic data. Numerical analysis of synthetic models show that the reconstructed magnetic data at the ground surface exhibits significant enhancement compared to the airborne data. The reduced-to-pole (RTP) and the analytic signal filters are applied to the magnetic data to show better maps of the magnetic anomalies. Four remote sensing evidential layers including argillic, phyllic, propylitic and hydroxyl alterations are extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images in order to map the altered areas associated with porphyry copper deposits. Principal component analysis (PCA) based on six Enhanced Thematic Mapper Plus (ETM+) images is implemented to map iron oxide layer. The final mineral prospectivity map based on desired geo-data set indicates adequately matching of high potential zones with previous working mines and copper deposits.

  12. Investigation of bacterial effects of Asian dust events through comparison with seasonal variability in outdoor airborne bacterial community

    PubMed Central

    Park, Jonguk; Ichijo, Tomoaki; Nasu, Masao; Yamaguchi, Nobuyasu

    2016-01-01

    Atmospheric bacterial dispersion with aeolian dust has been reported to have a potential impact on public health and ecosystems. Asian dust is a major aeolian event that results in an estimated 4 million tons of Asian dust particles falling in Japan annually, 3,000–5,000 km away from their source regions. However, most studies have only investigated the effects of Asian dust during dust seasons. Therefore, in this study, outdoor bacterial abundance and community composition were determined by 16S rRNA quantitative PCR and amplicon sequencing, respectively, and compared on Asian and non-Asian dust days (2013–2015; 44 samples over four seasons). Seasonal variations in bacterial abundance of non-Asian dust days were not observed. Bacterial abundance of individual samples collected on non-Asian dust days changed dynamically relative to Asian dust days, with bacterial abundance occasionally reaching those of Asian dust days. The bacterial community composition on non-Asian dust days was rather stable seasonally, and did not differ from that on Asian dust days. These results indicate that bacteria in Asian dust does not immediately influence indigenous bacterial communities at the phylum/class level in distant downwind areas; accordingly, further studies of bacterial communities in downwind areas closer to the dust source are warranted. PMID:27761018

  13. Chest radiography in dust-exposed miners: Promise and problems, potential and imperfections

    SciTech Connect

    Wagner, G.R.; Attfield, M.D.; Parker, J.E. )

    1993-01-01

    Since the early 1900s, it was recognized that many dust-exposed workers developed abnormal radiographs during life. Chest radiography remains the primary means of determining the presence and extent of dust-induced pneumoconiosis, although it is ineffective for detecting airways obstructions from mine dust exposure. This chapter reviews the uses and limitations of chest radiography in the study, surveillance, screening, clinical diagnosis, and disability determinations of occupational lung diseases in dust-exposed workers. 70 refs.

  14. Imaginary refractive index and other microphysical properties of volcanic ash, Sarahan dust, and other mineral aerosols

    NASA Astrophysics Data System (ADS)

    Rocha Lima, A.; Martins, J.; Krotkov, N. A.; Artaxo, P.; Todd, M.; Ben Ami, Y.; Dolgos, G.; Espinosa, R.

    2013-12-01

    Aerosol properties are essential to support remote sensing measurements, atmospheric circulation and climate models. This research aims to improve the understanding of the optical and microphysical properties of different types of aerosols particles. Samples of volcanic ash, Saharan dust and other mineral aerosols particles were analyzed by different techniques. Ground samples were sieved down to 45um, de-agglomerated and resuspended in the laboratory using a Fluidized Bed Aerosol Generator (FBAG). Particles were collected on Nuclepore filters into PM10, PM2.5, or PM1.0. and analyzed by different techniques, such as Scanning Electron Microscopy (SEM) for determination of size distribution and shape, spectral reflectance for determination of the optical absorption properties as a function of the wavelength, material density, and X-Ray fluorescence for the elemental composition. The spectral imaginary part of refractive index from the UV to the short wave infrared (SWIR) wavelength was derived empirically from the measurements of the spectral mass absorption coefficient, size distribution and density of the material. Some selected samples were also analyzed with the Polarized Imaging Nephelometer (PI-Neph) instrument for the characterization of the aerosol polarized phase function. This work compares results of the spectral refractive index of different materials obtained by our methodology with those available in the literature. In some cases there are significant differences both in magnitude and spectral dependence of the imaginary refractive index. These differences are evaluated and discussed in this work.

  15. Mineral phases and metals in baghouse dust from secondary aluminum production.

    PubMed

    Huang, Xiao-Lan; El Badawy, Amro M; Arambewela, Mahendranath; Adkins, Renata; Tolaymat, Thabet

    2015-09-01

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 μg L(-1) As; >1000 μg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities). PMID:25898346

  16. CYTOTOXIC EFFECTS OF SOME MINERAL DUSTS ON SYRIAN HAMSTER PERITONEAL MACROPHAGES

    PubMed Central

    Bey, Elke; Harington, J. S.

    1971-01-01

    Hamster peritoneal macrophages were grown in cell culture and their response to various conditions was examined. The cultures responded favorably to high concentrations of serum and to medium which had been preconditioned by contact with tumor cells. After 2–3 days of adaptation, they entered into a period of stability which lasted from the 4th to the 9th day. Macrophage cultures in this stable phase were treated with various samples of mineral dusts and their response determined by counting the number of viable macrophages/cm2 at intervals over a period of 72 hr. Crystalline silica Snowit was found to be nontoxic. Amorphous silica Fransil caused a characteristic cytotoxic effect and a rapid decline in cell population at doses less than 150 µg/5 x 105 cells. Of the three different kinds of asbestos used, chrysotile was toxic and amosite and crocidolite nontoxic at equivalent concentrations. A comparison of two preparations of chrysotile which differed in surface area showed that weight rather than surface area determines toxicity. Pretreatment of chrysotile with tryptose phosphate broth under drastic conditions accelerated but did not increase the final intensity of the cytotoxic effect. PMID:4101804

  17. Mineral phases and metals in baghouse dust from secondary aluminum production.

    PubMed

    Huang, Xiao-Lan; El Badawy, Amro M; Arambewela, Mahendranath; Adkins, Renata; Tolaymat, Thabet

    2015-09-01

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 μg L(-1) As; >1000 μg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities).

  18. Synchrotron FTIR Examination of Interplanetary Dust Particles: An Effort to Determine the Compounds and Minerals in Interstellar and Circumstellar Dust

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Keller, L. P.

    2002-01-01

    Some interplanetary dust particles (IDPs), collected by NASA from the Earth's stratosphere, are the most primitive extraterrestrial material available for laboratory analysis. Many exhibit isotopic anomalies in H, N, and O, suggesting they contain preserved interstellar matter. We report the preliminary results of a comparison of the infrared absorption spectra of subunits of the IDPs with astronomical spectra of interstellar grains.

  19. An Assessment of the Surface Longwave Direct Radiative Effect of Airborne Dust in Zhangye China During the Asian Monsoon Year Field Experiment (2008)

    NASA Technical Reports Server (NTRS)

    Hansell, Richard A.; Tsay, Si-Chee; Hsu, N. Christina; Ji, Qiang; Bell, Shaun W.; Holben, Brent N.; Ellsworth, Welton J.; Roush, Ted L.; Zhang, Wu; Huang, J.; Li, Zhanquing; Chen, Hongbin

    2012-01-01

    Tiny suspensions of solid particles or liquid droplets, called aerosols, hover in earth's atmosphere and can be found over just about anywhere including oceans, deserts, vegetated areas, and other global regions. Aerosols come in a variety of sizes, shapes, and compositions which depend on such factors as their origin and how long they have been in the atmosphere (i.e., their residence time). Some of the more common types of aerosols include mineral dust and sea salt which get lifted from the desert and ocean surfaces, respectively by mechanical forces such as strong winds. Depending on their size, aerosols will either fall out gravitationally, as in the case of larger particles, or will remain resident in the atmosphere where they can undergo further change through interactions with other aerosols and cloud particles. Not only do aerosols affect air quality where they pose a health risk, they can also perturb the distribution of radiation in the earth-atmosphere system which can inevitably lead to changes in our climate. One aerosol that has been in the forefront of many recent studies, particularly those examining its radiative effects, is mineral dust. The large spatial coverage of desert source regions and the fact that dust can radiatively interact with such a large part of the electromagnetic spectrum due to its range in particle size, makes it an important aerosol to study. Dust can directly scatter and absorb solar and infrared radiation which can subsequently alter the amount of radiation that would otherwise be present in the absence of dust at any level of the atmosphere like the surface. This is known as radiative forcing. At the surface dust can block incoming solar energy, however at infrared wavelengths, dust acts to partially compensate the solar losses. Evaluating the solar radiative effect of dust aerosols is relatively straightforward due in part to the relatively large signal-to-noise ratio in the measurements. At infrared wavelengths, on the

  20. On realistic size equivalence and shape of spheroidal Saharan mineral dust particles applied in solar and thermal radiative transfer calculations

    NASA Astrophysics Data System (ADS)

    Otto, S.; Trautmann, T.; Wendisch, M.

    2011-05-01

    Realistic size equivalence and shape of Saharan mineral dust particles are derived from in-situ particle, lidar and sun photometer measurements during SAMUM-1 in Morocco (19 May 2006), dealing with measured size- and altitude-resolved axis ratio distributions of assumed spheroidal model particles. The data were applied in optical property, radiative effect, forcing and heating effect simulations to quantify the realistic impact of particle non-sphericity. It turned out that volume-to-surface equivalent spheroids with prolate shape are most realistic: particle non-sphericity only slightly affects single scattering albedo and asymmetry parameter but may enhance extinction coefficient by up to 10 %. At the bottom of the atmosphere (BOA) the Saharan mineral dust always leads to a loss of solar radiation, while the sign of the forcing at the top of the atmosphere (TOA) depends on surface albedo: solar cooling/warming over a mean ocean/land surface. In the thermal spectral range the dust inhibits the emission of radiation to space and warms the BOA. The most realistic case of particle non-sphericity causes changes of total (solar plus thermal) forcing by 55/5 % at the TOA over ocean/land and 15 % at the BOA over both land and ocean and enhances total radiative heating within the dust plume by up to 20 %. Large dust particles significantly contribute to all the radiative effects reported. They strongly enhance the absorbing properties and forward scattering in the solar and increase predominantly, e.g., the total TOA forcing of the dust over land.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  3. Vertical mass impact and features of Saharan dust intrusions derived from ground-based remote sensing in synergy with airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Córdoba-Jabonero, Carmen; Andrey-Andrés, Javier; Gómez, Laura; Adame, José Antonio; Sorribas, Mar; Navarro-Comas, Mónica; Puentedura, Olga; Cuevas, Emilio; Gil-Ojeda, Manuel

    2016-10-01

    A study of the vertical mass impact of Saharan dust intrusions is presented in this work. Simultaneous ground-based remote-sensing and airborne in-situ measurements performed during the AMISOC-TNF campaign over the Tenerife area (Canary Islands) in summertime from 01 July to 11 August 2013 were used for that purpose. A particular dusty (DD) case, associated to a progressively arriving dust intrusion lasting for two days on 31 July (weak incidence) and 01 August (strong incidence), is especially investigated. AERONET AOD and AEx values were ranging, respectively, from 0.2 to 1.4 and 0.35 to 0.05 along these two days. Vertical particle size distributions within fine and coarse modes (0.16-2.8 μm range) were obtained from aircraft aerosol spectrometer measurements. Extinction profiles and Lidar Ratio (LR) values were derived from MPLNET/Micro Pulse Lidar observations. MAXDOAS measurements were also used to retrieve the height-resolved aerosol extinction for evaluation purposes in comparison to Lidar-derived profiles. The synergy between Lidar observations and airborne measurements is established in terms of the Mass Extinction Efficiency (MEE) to calculate the vertical mass concentration of Saharan dust particles. Both the optical and microphysical profilings show dust particles mostly confined in a layer of 4.3 km thickness from 1.7 to 6 km height. LR ranged between 50 and 55 sr, typical values for Saharan dust particles. In addition, this 2-day dust event mostly affected the Free Troposphere (FT), being less intense in the Boundary Layer (BL). In particular, rather high Total Mass Concentrations (TMC) were found on the stronger DD day (01 August 2013): 124, 70 and 21 μg m-3 were estimated, respectively, at FT and BL altitudes and on the near-surface level. This dust impact was enhanced due to the increase of large particles affecting the FT, but also the BL, likely due to their gravitational settling. However, the use of an assumed averaged MEE value can be

  4. Analysis of Measurements of Saharan Dust by Airborne and Ground-based Remote Sensing Methods during the Puerto Rico Dust Experiment (PRIDE)

    NASA Technical Reports Server (NTRS)

    Reid, Jeffrey S.; Kinney, James E.; Westphal, Douglas L.; Holben, Brent N.; Welton, E. Judd; Tsay, Si-Chee; Eleuterio, Daniel P.; Campbell, James; Christopher, Sundar A.; Jonsson, Haflidi H.

    2003-01-01

    For 26 days in mid-June and July 2000, a research group comprised of U.S. Navy, NASA, and university scientists conducted the Puerto Rico Dust Experiment (PRIDE). In this paper we give a brief overview of mean meteorological conditions during the study. We focus on findings on African dust transported into the Caribbean utilizing Navajo aircraft and AERONET Sun photometer data. During the study midvisible aerosol optical thickness (AOT) in Puerto Rico averaged 0.25, with a maximum less than 0.5 and with clean marine periods of _0.08. Dust AOTs near the coast of Africa (Cape Verde Islands and Dakar) averaged _0.4, 30% less than previous years. By analyzing dust vertical profiles in addition to supplemental meteorology and MPLNET lidar data we found that dust transport cannot be easily categorized into any particular conceptual model. Toward the end of the study period, the vertical distribution of dust was similar to the commonly assumed Saharan Air Layer (SAL) transport. During the early periods of the study, dust had the highest concentrations in the marine and convective boundary layers with only a, weak dust layer in the SAL being present, a state usually associated with wintertime transport patterns. We corroborate the findings of Maring et al. that in most cases, there was an unexpected lack of vertical stratification of dust particle size. We systematically analyze processes which may impact dust vertical distribution and determine and speculate that dust vertical distribution predominately influenced by flow patterns over Africa and differential advection couple with mixing by easterly waves and regional subsidence.

  5. Clear Sky Column Closure Studies of Urban-Marine and Mineral-Dust Aerosols Using Aircraft, Ship, Satellite and Ground-Based Measurements in ACE-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Russell, Philip B.; Livingston, John M.; Gasso, Santiago; Hegg, Dean A.; Collins, Donald R.; Flagan, Richard C.; Seinfeld, John H.; Oestroem, Elisabeth; Noone, Kevin J.; Durkee, Philip A.; Jonsson, Haflidi H.; Welton, Ellsworth J.; Voss, Kenneth J.; Gordon, Howard R.; Formenti, Paola; Andreae, Meinrat O.; Kapustin, Vladimir N.; Bates, Timothy S.; Quinn, Patricia K.

    2000-01-01

    As part of the second Aerosol Characterization Experiment (ACE-2), European urban-marine and African mineral-dust aerosols were measured aboard the Pelican aircraft, the Research Vessel Vodyanitskiy from the ground and from satellites.

  6. Airborne manganese as dust vs. fume determining blood levels in workers at a manganese alloy production plant.

    PubMed

    Park, Robert M; Baldwin, Mary; Bouchard, Maryse F; Mergler, Donna

    2014-12-01

    The appropriate exposure metrics for characterizing manganese (Mn) exposure associated with neurobehavioral effects have not been established. Blood levels of Mn (B-Mn) provide a potentially important intermediate marker of Mn airborne exposures. Using data from a study of a population of silicon- and ferro-manganese alloy production workers employed between 1973 and 1991, B-Mn levels were modeled in relation to prior Mn exposure using detailed work histories and estimated respirable Mn concentrations from air-sampling records. Despite wide variation in exposure levels estimated for individual jobs, duration of employment (exposure) was itself a strong predictor of B-Mn levels and strongest when an 80-day half-life was applied to contributions over time (t=6.95, 7.44, respectively; p<10(-5)). Partitioning exposure concentrations based on process origin into two categories: (1) "large" respirable particulate (Mn-LRP) derived mainly from mechanically generated dust, and (2) "small" respirable particulate (Mn-SRP) primarily electric furnace condensation fume, revealed that B-Mn levels largely track the small, fume exposures. With a half-life of 65 days applied in a model with cumulative exposure terms for both Mn-LRP (t=-0.16, p=0.87) and Mn-SRP (t=6.45, p<10(-5)), the contribution of the large-size fraction contribution was negligible. Constructing metrics based on the square root of SRP exposure concentrations produced a better model fit (t=7.87 vs. 7.44, R(2)=0.2333 vs. 0.2157). In a model containing both duration (t=0.79, p=0.43) and (square root) fume (t=2.47, p=0.01) metrics, the duration term was a weak contributor. Furnace-derived, small respirable Mn particulate appears to be the primary contributor to B-Mn levels, with a dose-rate dependence in a population chronically exposed to Mn, with air-concentrations declining in recent years. These observations may reflect the presence of homeostatic control of Mn levels in the blood and other body tissues and be

  7. Mineral magnetism of atmospheric dust over southwest coast of India: Impact of anthropogenic activities and implications to public health

    NASA Astrophysics Data System (ADS)

    Warrier, Anish Kumar; Shankar, R.; Manjunatha, B. R.; Harshavardhana, B. G.

    2014-03-01

    We have used rock magnetic techniques in this study to assess atmospheric pollution at five stations in and around Mangalore city on the southwestern coast of India. Samples of dust were collected from two suburban areas (Thokkottu and Pumpwell located respectively ~ 10 km and 3 km from the city center), the city center itself (Milagres) and industrial/port areas (Panambur and Mangalore Refinery and Petrochemicals Limited (MRPL)). Low-frequency magnetic susceptibility (χlf), frequency-dependent susceptibility (χfd), susceptibility of anhysteretic remanent magnetization (χARM) and isothermal remanent magnetization (IRM 20 to 1000 mT) were determined on 23 dust samples and inter-parametric ratios calculated. Results show that samples from suburban areas (particularly Thokkottu) are characterized by low χlf (< 314.1 × 10- 8 m3 kg- 1) and up to 6% χfd, suggesting low levels of pollution and the presence of pedogenic magnetite possibly derived from soils by wind erosion. However, the average χlf of Milagres, Panambur and MRPL dust samples is high by factors of 9.2, 3.3 and 2.6 compared to that of the Thokkottu sample. The Milagres sample contains magnetically "soft" minerals like magnetite, possibly indicating its derivation from motor vehicle exhaust. In contrast, the Panambur dust sample is characterized by magnetically "hard" minerals such as hematite and goethite as it has an 8-fold higher HIRM value compared to the Thokkottu sample. This magnetic signature is perhaps the result of dust particles derived from the grinding of hematite-rich iron ore by the Kudremukh Iron Ore Company Limited (KIOCL) at Panambur and its storage and export through the nearby New Mangalore Port. However, the dust sample from MRPL has magnetically "soft" minerals like magnetite. This magnetic mineral may have originated from petroleum refining processes at MRPL. Particulate pollution from industrial activities and motor vehicle exhaust is a threat to human health and is known to

  8. Characterizing Geology and Mineralization at High Latitudes in Alaska Using Airborne and Field-Based Imaging Spectrometer Data

    NASA Astrophysics Data System (ADS)

    Hoefen, T. M.; Kokaly, R. F.; Graham, G. E.; Kelley, K. D.; Buchhorn, M.; Johnson, M. R.; Hubbard, B. E.; Goldfarb, R. J.; Prakash, A.

    2015-12-01

    Passive optical remote sensing of high latitude regions faces many challenges including a short acquisition season and poor illumination. Identification of surface minerals can be complicated by steep terrain and vegetation cover. In July 2014, the HyMap* imaging spectrometer was flown over two study areas in Alaska. Contemporaneously, field spectra and samples of geologic units were collected, including altered and unaltered parts of intrusions hosting mid-Cretaceous porphyry copper deposits at Orange Hill and Bond Creek in the eastern Alaska Range. The HyMap radiance data were converted to surface reflectance using a radiative transfer correction program and reflectance spectra of calibration sites. Reflectance data were analyzed with the Material Identification and Characterization Algorithm (MICA), a module of USGS PRISM (Processing Routines in IDL for Spectroscopic Measurements; speclab.cr.usgs.gov). Large areas of abundant epidote/chlorite, muscovite/illite, calcite, kaolinite, montmorillonite, and (or) pyrophyllite were mapped, which are minerals typically formed during alteration of host rocks surrounding porphyry copper deposits. A map showing the wavelength position of the muscovite/illite absorption feature was made. Shifts in wavelength position have been related to the aluminum composition of micas and areas of high metal concentrations in past studies. In July 2015, rock and spectral sampling was continued in areas with surface exposures of copper- and molybdenum-bearing sulfides. Also, high-spatial resolution (~6 cm pixel size) imaging spectrometer data were collected at the Orange Hill deposit using the University of Alaska, Fairbanks (UAF) HySpex imaging spectrometer (www.hyperspectral.alaska.edu). Laboratory, field, and airborne spectra are being examined to define indicators of mineralization. The study results will be used to assess the effectiveness of spectroscopic remote sensing for geologic mapping and exploration targeting in Alaska and

  9. China Dust

    Atmospheric Science Data Center

    2013-04-16

    ... SpectroRadiometer (MISR) nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a ... arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the ...

  10. Scavenging of pollutant acid substances by Asian mineral dust particles - article no. L07816

    SciTech Connect

    Matsumoto, J.; Takahashi, K.; Matsumi, Y.; Yabushita, A.; Shimizu, A.; Matsui, I.; Sugimoto, N.

    2006-04-13

    Uptakes of sulfate and nitrate onto Asian dust particles during transport from the Asian continent to the Pacific Ocean were analyzed by using a single-particle time-of-flight mass spectrometer. Observation was conducted at Tsukuba in Japan in the springtime of 2004. Sulfate-rich dust particles made their largest contribution during the 'dust event' in the middle of April 2004. As a result of detailed analysis including backward trajectory calculations, it was confirmed that sulfate components originating from coal combustion in the continent were internally mixed with dust particles. Even in the downstream of the outflow far from the continental coastline, significant contribution of Asian dust to sulfate was observed. Asian dust plays critical roles as the carrier of sulfate over the Pacific Ocean.

  11. Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

    SciTech Connect

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    2014-06-15

    Radioactive fission product {sup 131}I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, {sup 134}Cs and {sup 137}Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m{sup -3} in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of {sup 134}Cs and {sup 137}Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m{sup -3}) variation of stable cesium ({sup 133}Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  12. Correlation between Asian Dust and Specific Radioactivities of Fission Products Included in Airborne Samples in Tokushima, Shikoku Island, Japan, Due to the Fukushima Nuclear Accident

    NASA Astrophysics Data System (ADS)

    Sakama, M.; Nagano, Y.; Kitade, T.; Shikino, O.; Nakayama, S.

    2014-06-01

    Radioactive fission product 131I released from the Fukushima Daiichi Nuclear Power Plants (FD-NPP) was first detected on March 23, 2011 in an airborne aerosol sample collected at Tokushima, Shikoku Island, located in western Japan. Two other radioactive fission products, 134Cs and 137Cs were also observed in a sample collected from April 2 to 4, 2011. The maximum specific radioactivities observed in this work were about 2.5 to 3.5 mBq×m-3 in a airborne aerosol sample collected on April 6. During the course of the continuous monitoring, we also made our first observation of seasonal Asian Dust and those fission products associated with the FDNPP accident concurrently from May 2 to 5, 2011. We found that the specific radioactivities of 134Cs and 137Cs decreased drastically only during the period of Asian Dust. And also, it was found that this trend was very similar to the atmospheric elemental concentration (ng×m-3) variation of stable cesium (133Cs) quantified by elemental analyses using our developed ICP-DRC-MS instrument.

  13. Optical properties of mineral dust aerosol including analysis of particle size, composition, and shape effects, and the impact of physical and chemical processing

    NASA Astrophysics Data System (ADS)

    Alexander, Jennifer Mary

    Atmospheric mineral dust has a large impact on the earth's radiation balance and climate. The radiative effects of mineral dust depend on factors including, particle size, shape, and composition which can all be extremely complex. Mineral dust particles are typically irregular in shape and can include sharp edges, voids, and fine scale surface roughness. Particle shape can also depend on the type of mineral and can vary as a function of particle size. In addition, atmospheric mineral dust is a complex mixture of different minerals as well as other, possibly organic, components that have been mixed in while these particles are suspended in the atmosphere. Aerosol optical properties are investigated in this work, including studies of the effect of particle size, shape, and composition on the infrared (IR) extinction and visible scattering properties in order to achieve more accurate modeling methods. Studies of particle shape effects on dust optical properties for single component mineral samples of silicate clay and diatomaceous earth are carried out here first. Experimental measurements are modeled using T-matrix theory in a uniform spheroid approximation. Previous efforts to simulate the measured optical properties of silicate clay, using models that assumed particle shape was independent of particle size, have achieved only limited success. However, a model which accounts for a correlation between particle size and shape for the silicate clays offers a large improvement over earlier modeling approaches. Diatomaceous earth is also studied as an example of a single component mineral dust aerosol with extreme particle shapes. A particle shape distribution, determined by fitting the experimental IR extinction data, used as a basis for modeling the visible light scattering properties. While the visible simulations show only modestly good agreement with the scattering data, the fits are generally better than those obtained using more commonly invoked particle shape

  14. MISR Decadal Observations of Mineral Dust: Property Characterization and Climate Applications

    NASA Technical Reports Server (NTRS)

    Kalashnikova, Olga V.; Garay, Michael J.; Sokolik, Irina; Kahn, Ralph A.; Lyapustin, A.; Diner, David J.; Lee, Jae N.; Torres, Omar; Leptoukh, Gregory G.; Sabbah, Ismail

    2012-01-01

    The Multi-angle Imaging SpectroRadiometer (MISR) provides a unique, independent source of data for studying dust emission and transport. MISR's multiple view angles allow the retrieval of aerosol properties over bright surfaces, and such retrievals have been shown to be sensitive to the non-sphericity of dust aerosols over both land and water. MISR stereographic views of thick aerosol plumes allow height and instantaneous wind derivations at spatial resolutions of better than 1.1 km horizontally and 200m vertically. We will discuss the radiometric and stereo-retrieval capabilities of MISR specifically for dust, and demonstrate the use of MISR data in conjunction with other available satellite observations for dust property characterization and climate studies.First, we will discuss MISR non-spherical (dust) fraction product over the global oceans. We will show that over the Atlantic Ocean, changes in the MISR-derived non-spherical AOD fraction illustrate the evolution of dust during transport. Next, we will present a MISR satellite perspective on dust climatology in major dust source regions with a particular emphasis on the West Africa and Middle East and discuss MISR's unique strengths as well as current product biases. Finally, we will discuss MISR dust plume product and climatological applications.

  15. Expert system-based mineral mapping in northern Death Valley, California/Nevada, using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

    NASA Technical Reports Server (NTRS)

    Kruse, F. A.; Lefkoff, A. B.; Dietz, J. B.

    1993-01-01

    Integrated analysis of imaging spectrometer data and field spectral measurements were used in conjunction with conventional geologic field mapping to characterize bedrock and surficial geology at the northern end of Death Valley, California and Nevada. A knowledge-based expert system was used to automatically produce image maps showing the principal surface mineralogy from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data. Linear spectral unmixing of the AVIRIS data allowed further determination of relative mineral, abundances and identification of mineral assemblages and mixtures. The imaging spectrometer data show the spatial distribution of spectrally distinct minerals occurring both as primary rockforming minerals and as alteration and weathering products. Field spectral measurements were used to verify the mineral maps and field mapping was used to extend the remote sensing results. Geographically referenced image maps produced from these data form new base maps from which to develop improved understanding of the processes of deposition and erosion affecting the present land surface.

  16. Abrupt Late Holocene Shift in Atmospheric Circulation Recorded by Mineral Dust in the Siple Dome Ice Core, Antarctica

    NASA Astrophysics Data System (ADS)

    Koffman, B. G.; Goldstein, S. L.; Kaplan, M. R.; Winckler, G.; Bory, A. J. M.; Biscaye, P.

    2015-12-01

    Atmospheric dust directly influences Earth's climate by altering the radiative balance and by depositing micronutrients in the surface ocean, affecting global biogeochemical cycling. In addition, mineral dust particles provide observational evidence constraining past atmospheric circulation patterns. Because dust can originate from both local and distant terrestrial sources, knowledge of dust provenance can substantially inform our understanding of past climate history, atmospheric transport pathways, and differences in aerosol characteristics between glacial and interglacial climate states. Dust provenance information from Antarctic ice cores has until now been limited to sites in East Antarctica. Here we present some of the first provenance data from West Antarctica. We use Sr-Nd isotopes to characterize dust extracted from late Holocene ice (~1000-1800 C.E.) from the Siple Dome ice core. The data form a tight array in Sr-Nd isotope space, with 87Sr/86Sr ranging between ~0.7087 and 0.7102, and ɛNd ranging between ~ -7 and -16. This combination is unique for Antarctica, with low Nd and low Sr isotope ratios compared to high-elevation East Antarctic sites, requiring a dust source from ancient (Archean to early Proterozoic) and unweathered continental crust, which mixes with young volcanic material. Both components are likely sourced from Antarctica. We also observe significant, systematic variability in Sr and Nd isotopic signatures through time, reflecting changes in the mixing ratio of these sources, and hypothesize that these changes are driven by shifts in circulation patterns. A large change occurs over about 10 years at ca. 1125 C.E. (ΔɛNd = +3 and Δ87Sr/86Sr = -0.0014). This shift coincides with changes in climate proxies in Southern Hemisphere paleoclimate records reflecting variability in the Westerlies. We therefore interpret the shift in dust provenance at Siple Dome to be related to larger-scale circulation changes. In general, the observed shifts

  17. A comparison of the physical and optical properties of anthropogenic air pollutants and mineral dust over Northwest China

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Pu, Wei; Shi, Jinsen; Bi, Jianrong; Zhou, Tian; Zhang, Xueying; Ren, Yong

    2015-04-01

    Emissions of mineral dust and its mixing with anthropogenic air pollutants affect both regional and global climates. Our fieldwork in late spring 2007 (April 25-June 15) measured the physical and optical properties of dust storms mixed with local air pollutants at a rural site about 48 km southeast of central Lanzhou. Levels of air pollutants and aerosol optical properties were observed during the experiment, with concentrations of NOx (6.8 ± 3.3 ppb, average ± standard deviation), CO (694 ± 486 ppb), SO2 (6.2 ± 10 ppb), O3 (50.7 ± 13.1 ppb), and PM10 (172 ± 180 μg m-3), and aerosol scattering coefficient (164 ± 89 Mm-1; 1 Mm = 106 m) and absorption coefficient (11.7 ± 6.6 Mm-1), all much lower than the values observed during air pollution episodes in urban areas. During a major dust storm, the mass concentration of PM10 reached 4072 μg m-3, approximately 21-fold higher than in non-dust storm periods. The mixing ratios of trace gases declined noticeably after a cold front passed through. The observed CO/SO2 and CO/NOx ratios during air pollution episodes were 4.2-18.3 and 13.7-80.5, respectively, compared with the corresponding ratios of 38.1-255.7 and 18.0-245.9 during non-pollution periods. Our investigations suggest that dust storms have a significant influence on air quality in areas far from their source, and this large-scale transport of dust and air pollutants produces major uncertainties in the quantification of the global effects of emissions over Northwest China.

  18. Minerals

    MedlinePlus

    Minerals are important for your body to stay healthy. Your body uses minerals for many different jobs, including building bones, making ... regulating your heartbeat. There are two kinds of minerals: macrominerals and trace minerals. Macrominerals are minerals your ...

  19. Airborne mineral components and trace metals in Paris region: spatial and temporal variability.

    PubMed

    Poulakis, E; Theodosi, C; Bressi, M; Sciare, J; Ghersi, V; Mihalopoulos, N

    2015-10-01

    A variety of mineral components (Al, Fe) and trace metals (V, Cr, Mn, Ni, Cu, Zn, Cd, Pb) were simultaneously measured in PM2.5 and PM10 fractions at three different locations (traffic, urban, and suburban) in the Greater Paris Area (GPA) on a daily basis throughout a year. Mineral species and trace metal levels measured in both fractions are in agreement with those reported in the literature and below the thresholds defined by the European guidelines for toxic metals (Cd, Ni, Pb). Size distribution between PM2.5 and PM10 fractions revealed that mineral components prevail in the coarse mode, while trace metals are mainly confined in the fine one. Enrichment factor analysis, statistical analysis, and seasonal variability suggest that elements such as Mn, Cr, Zn, Fe, and Cu are attributed to traffic, V and Ni to oil combustion while Cd and Pb to industrial activities with regional origin. Meteorological parameters such as rain, boundary layer height (BLH), and air mass origin were found to significantly influence element concentrations. Periods with high frequency of northern and eastern air masses (from high populated and industrialized areas) are characterized by high metal concentrations. Finally, inner city and traffic emissions were also evaluated in PM2.5 fraction. Significant contributions (>50 %) were measured in the traffic site for Mn, Fe, Cr, Zn, and Cu, confirming that vehicle emissions contribute significantly to their levels, while in the urban site, the lower contributions (18 to 33 %) for all measured metals highlight the influence of regional sources on their levels.

  20. Colloidal stability of nanoparticles derived from simulated cloud-processed mineral dusts.

    PubMed

    Kadar, Enikö; Fisher, Andrew; Stolpe, Björn; Calabrese, Sergio; Lead, Jamie; Valsami-Jones, Eugenia; Shi, Zongbo

    2014-01-01

    Laboratory simulation of cloud processing of three model dust types with distinct Fe-content (Moroccan dust, Libyan dust and Etna ash) and reference goethite and ferrihydrite were conducted in order to gain a better understanding of natural nanomaterial inputs and their environmental fate and bioavailability. The resulting nanoparticles (NPs) were characterised for Fe dissolution kinetics, aggregation/size distribution, micromorphology and colloidal stability of particle suspensions using a multi-method approach. We demonstrated that the: (i) acid-leachable Fe concentration was highest in volcanic ash (1 m Mg(-1) dust) and was followed by Libyan and Moroccan dust with an order of magnitude lower levels; (ii) acid leached Fe concentration in the<20 nm fraction was similar in samples processed in the dark with those under artificial sunlight, but average hydrodynamic diameter of NPs after cloud-processing (pH~6) was larger in the former; iii) NPs formed at pH~6 were smaller and less poly-disperse than those at low pH, whilst unaltered zeta potentials indicated colloidal instability; iv) relative Fe percentage in the finer particles derived from cloud processing does not reflect Fe content of unprocessed dusts (e.g. volcanic ash>Libyan dust). The common occurrence of Fe-rich "natural nanoparticles" in atmospheric dust derived materials may indicate their more ubiquitous presence in the marine environment than previously thought.

  1. Radiative impact of mineral dust on monsoon precipitation variability over West Africa

    SciTech Connect

    Zhao, Chun; Liu, Xiaohong; Leung, Lai-Yung R.; Hagos, Samson M.

    2011-03-01

    The radiative forcing of dust and its impact on precipitation over the West Africa monsoon (WAM) region is simulated using a coupled meteorology and aerosol/chemistry model (WRF-Chem). During the monsoon season, dust is a dominant contributor to AOD over West Africa. In the standard simulation, on 24-hour domain average, dust has a cooling effect (-6.11 W/m2) at the surface, a warming effect (6.94 W/m2) in the atmosphere, and a relatively small TOA forcing (0.83 W/m2). Dust modifies the surface energy budget and atmospheric diabatic heating and hence causes lower atmospheric cooling in the daytime but warming in the nighttime. As a result, atmospheric stability is increased in the daytime and reduced in the nighttime, leading to a reduction of late afternoon precipitation by up to 0.14 mm/hour (30%) and an increase of nocturnal and early morning precipitation by up to 0.04 mm/hour (23%) over the WAM region. Dust-induced reduction of diurnal precipitation variation improves the simulated diurnal cycle of precipitation when compared to measurements. However, daily precipitation is only changed by a relatively small amount (-0.14 mm/day or -4%). On the other hand, sensitivity simulations show that, for weaker-to-stronger absorbing dust, dust longwave warming effect in the nighttime surpasses its shortwave cooling effect in the daytime at the surface, leading to a less stable atmosphere associated with more convective precipitation in the nighttime. As a result, the dust-induced change of daily WAM precipitation varies from a significant reduction of -0.40 mm/day (-12%, weaker absorbing dust) to a small increase of 0.05 mm/day (1%, stronger absorbing dust). This variation originates from the competition between dust impact on daytime and nighttime precipitation, which depends on dust shortwave absorption. Dust reduces the diurnal variation of precipitation regardless of its absorptivity, but more reduction is associated with stronger absorbing dust.

  2. Evaluation of a regional mineral dust model over Northern Africa, Southern Europe and Middle East with AERONET data

    NASA Astrophysics Data System (ADS)

    Basart, S.; Pérez, C.; Cuevas, E.; Baldasano, J. M.

    2009-04-01

    the model to reproduce AOD (at 550nm) associated to mineral dust 24, 48 and 72h ahead. A suit of discrete statistics as Mean Normalized Bias Error (MNBE), Mean Normalized Gross Error (MNGE) and Root Mean Square Error (RMSE) has been used in order to evaluate the model behaviour. Categorical statistics or skill scores, as model accuracy, bias, probability of detection, false alarm rate and critical success index have been implemented to test the capability of the model to simulate AOD exceeding thresholds defined by the quartiles of each AERONET site. A previous aerosol characterization of AERONET data has been performed for our study region in order to discriminate desert dust contributions (Basart et al., 2008). The first results of the comparison reveal that the modelled dust field agrees in general reasonably well with sun photometer data. Since dust long-range transport is mainly driven by smaller dust particles, the results of this new 8-bins version (with increased number of dust size bins) is considerably better, since the small particle size range (<10µm effective radius) is well described. The best scores are found in North Africa and Middle East. In the Sahel region, an important sub-estimation is observed in wintertime, when the Atlantic outflow transport is important. This is partially due to the more complex processes associated to dust generation in this region (Warren et al., 2007), not well parameterized in dust models yet. Other causes, such as the correct simulation of regional winds or the threshold friction velocity are under research. Moreover, the interaction of mineral dust and biomass burning aerosols from Savannah fires is at its maximum over the region in this season. In southern Europe, the relative errors are higher than in the rest of our study domain mainly due to the presence of different types of aerosols (such as fine pollution aerosols) which appear well-mixed with desert dust. References: Basart, S., C. Pérez, E. Cuevas and J

  3. Effects on health of non-occupational exposure to airborne mineral fibres.

    PubMed

    Gardner, M J; Saracci, R

    1989-01-01

    The most prominent potential marker of disease-related non-occupational exposure to mineral fibres is mesothelioma. Although many cases of mesothelioma have resulted from occupational exposure to asbestos, some have been associated with para-occupational domestic and/or neighbourhood exposure and have been reported in case series, case-control studies and a cohort study among non-occupationally exposed subjects. However, little information is available on mesothelioma as a direct consequence of general environmental asbestos exposure. Such cases of mesothelioma related to non-occupational exposure to asbestos as have occurred to date are likely to have resulted from past exposures much higher than those prevailing at the present time (in the developed countries); numbers will therefore probably decrease in the future. Very high rates of mesothelioma have been reported as a result of exposure to erionite. No studies are available on the effects of non-occupational exposure to man-made mineral fibres but, among occupationally exposed workers, a risk of mesothelioma is not apparent. There are suggestions of raised lung cancer rates among household contacts of asbestos workers and among individuals exposed to erionite. Non-malignant parenchymal and pleural abnormalities have been observed in subjects exposed non-occupationally to asbestos and erionite, but these are not necessarily associated with malignant lesions. Quantitative risk estimates of adverse effects on health have not been derived from these studies, essentially because of the absence of fibre exposure measurements.

  4. Optical dust sensor for the mining industry

    NASA Astrophysics Data System (ADS)

    Sierakowski, Marek W.; Wolinski, Tomasz R.; Domanski, Andrzej W.; Osinska, Katarzyna

    2003-04-01

    One of many hazards in mining industry is presence of airborne dust on underground boards. Hazards caused by dust generated and spread in mines are of the two types: (1) health risk for miners from airborne dust produced from rocks, coal, soluble minerals (pneumoconiosis, toxicity), (2) danger of explosion of carbon dust. Dust particles produced in mines underground range from 0 to about 400 micrometers, have irregular shapes and prevailingly are strongly light absorbing. It is assumed that the most health-risky are particles between 1 μm and 5 μm in size. They are not visible with naked eyes, so their control and measurement need technical equipment. As a standard in polish mines, gravimetric measurement method is used at present. This method works well in post-event evaluation of total health-risk factor, but is not much useful for instantaneous risk warning. In order to recognize and possibly prevent the dust risk as it appears, other methods have to be used, like optical method. Looking towards this demand, an experimental optical dust sensor is demonstrated. The sensor is based on light scattering effect by dust particles, as usual do devices of this type. Originality of this solution lies in construction details of the sensor. Scattering is a complex function of dust kind, size, shape and concentration. Moreover, operating conditions of such a device are cruel -- humidity, elevated temperature, vibrations, and over-all contact with dust -- are harmful for optics. Thus, to achieve reliable indications of the sensor is really a challenge. This paper describes optical construction attempting to overcome difficulties in obtaining dust concentration sensor intended for mining industry and similar applications. First laboratory and operational tests are also reported.

  5. Modeling of the mineral contribution of dust to PM10 directly from the measurements of VIIRS Aerosol Optical Thickness

    NASA Astrophysics Data System (ADS)

    Albina, D. T.

    2015-12-01

    Northern Africa is well known as the largest producing region of dust, which is transported across the Atlantic to the Caribbean, under specific weather conditions. Saharan dust was observed, over the Caribbean Basin, to try to determine the roles they may play in human health, and in the fertilization of Amazon Forest. Scientists have not only used the satellite sensors MODIS and VIIRS to measure the volume of dust that makes this trans-Atlantic journey, but also the AERONET network of photometers, and PM10 Suspended Particulate Matter. We have successfully compared and shown a high correlation between the measurements from VIIRS aerosol optical thickness (AOT) and PM10 so that to be able to determine an accurate modeling of the mineral contribution of dust to PM10 directly from the measurements of VIIRS. The aim of this work is to show that it is possible to accurately forecast the daily mean concentration of PM10 using linear regression models. In this way, countries of the Caribbean region which cannot afford Particle Sensor for Pm10 will be able to have a precise idea of the PM10 daily forecast upon there region.

  6. Cross-shift peak expiratory flow changes are unassociated with respirable coal dust exposure among South African coal miners

    SciTech Connect

    Naidoo, R.N.; Robins, T.G.; Becklake, M.; Seixas, N.; Thompson, M.L.

    2007-12-15

    he objectives of this study were to determine whether cross-shift changes in peak expiratory flow rate (PEFR) were related to respirable dust exposure in South African coalminers. Fifty workers were randomly selected from a cohort of 684 miners from 3 bituminous coal mines in Mpumalanga, South Africa. Peak expiratory efforts were measured prior to the commencement of the shift, and at the end of the shift on at least two occasions separated by at least 2 weeks, with full shift personal dust sampling being conducted on each occasion for each participant. Interviews were conducted, work histories were obtained and cumulative exposure estimates were constructed. Regression models examined the associations of cross-shift changes in PEFR with current and cumulative exposure, controlling for shift, smoking and past history of tuberculosis. There were marginal differences in cross-shift PEFR (ranging from 0.1 to 2 L/min). Linear regression analyses showed no association between cross-shift change in PEFR and current or cumulative exposure. The specific shift worked by participants in the study showed no effect. Our study showed no association between current respirable dust exposure and cross-shift changes in PEFR. There was a non-significant protective effect of cumulative dust exposure on the outcome, suggesting the presence of a 'healthy worker survivor effect' in this data.

  7. Detection of hidden mineral deposits by airborne spectral analysis of forest canopies. [Spirit Lake, Washington; Catheart Mountain, Maine; Blacktail Mountain, Montana; and Cotter Basin, Montana

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.; Kuo, J. T.

    1984-01-01

    Data from field surveys and biogeochemical tests conducted in Maine, Montana, and Washington strongly correlate with results obtained using high resolution airborne spectroradiometer which detects an anomalous spectral waveform that appears definitely associated with sulfide mineralization. The spectral region most affected by mineral stress is between 550 nm and 750 nm. Spectral variations observed in the field occur on the wings of the red chlorophyll band centered at about 690 nm. The metal-stress-induced variations on the absorption band wing are most successfully resolved in the high spectral resolution field data using a waveform analysis technique. The development of chlorophyll pigments was retarded in greenhouse plants doped with copper and zinc in the laboratory. The lowered chlorophyll production resulted in changes on the wings of the chlorophyll bands of reflectance spectra of the plants. The airborne spectroradiometer system and waveform analysis remains the most sensitive technique for biogeochemical surveys.

  8. Iron oxide minerals in dust-source sediments from the Bodélé Depression, Chad: Implications for radiative properties and Fe bioavailability of dust plumes from the Sahara

    NASA Astrophysics Data System (ADS)

    Moskowitz, Bruce M.; Reynolds, Richard L.; Goldstein, Harland L.; Berquó, Thelma S.; Kokaly, Raymond F.; Bristow, Charlie S.

    2016-09-01

    Atmospheric mineral dust can influence climate and biogeochemical cycles. An important component of mineral dust is ferric oxide minerals (hematite and goethite) which have been shown to influence strongly the optical properties of dust plumes and thus affect the radiative forcing of global dust. Here we report on the iron mineralogy of dust-source samples from the Bodélé Depression (Chad, north-central Africa), which is estimated to be Earth's most prolific dust producer and may be a key contributor to the global radiative budget of the atmosphere as well as to long-range nutrient transport to the Amazon Basin. By using a combination of magnetic property measurements, Mössbauer spectroscopy, reflectance spectroscopy, chemical analysis, and scanning electron microscopy, we document the abundance and relative amounts of goethite, hematite, and magnetite in dust-source samples from the Bodélé Depression. The partition between hematite and goethite is important to know to improve models for the radiative effects of ferric oxide minerals in mineral dust aerosols. The combination of methods shows (1) the dominance of goethite over hematite in the source sediments, (2) the abundance and occurrences of their nanosize components, and (3) the ubiquity of magnetite, albeit in small amounts. Dominant goethite and subordinate hematite together compose about 2% of yellow-reddish dust-source sediments from the Bodélé Depression and contribute strongly to diminution of reflectance in bulk samples. These observations imply that dust plumes from the Bodélé Depression that are derived from goethite-dominated sediments strongly absorb solar radiation. The presence of ubiquitous magnetite (0.002-0.57 wt%) is also noteworthy for its potentially higher solubility relative to ferric oxide and for its small sizes, including PM < 0.1 μm. For all examined samples, the average iron apportionment is estimated at about 33% in ferric oxide minerals, 1.4% in magnetite, and 65% in

  9. Seasonal variations of sugars in atmospheric particulate matter from Gosan, Jeju Island: Significant contributions of airborne pollen and Asian dust in spring

    NASA Astrophysics Data System (ADS)

    Fu, Pingqing; Kawamura, Kimitaka; Kobayashi, Minoru; Simoneit, Bernd R. T.

    2012-08-01

    Sugars are important water-soluble organic constituents of atmospheric particulate matter (PM). In order to better understand the sources and seasonal variations of sugars in aerosols, primary saccharides (fructose, glucose, sucrose, and trehalose) and sugar alcohols (arabitol and mannitol), together with levoglucosan, have been studied in ambient aerosols at Gosan, Jeju Island in the western North Pacific, the downwind region of the Asian outflow, using gas chromatography-mass spectrometry. The results showed that the sugar composition varied seasonally with a total concentration range of 6.8-1760 ng m-3 (mean 246 ng m-3). The total identified sugars had the highest concentration in April, the spring bloom season at Jeju Island, when sucrose contributed up to 80% of the total sugars. The dominance of sucrose was also detected in pollen samples, suggesting that pollen can contribute significantly to sucrose in aerosols during the spring bloom. The seasonal variation of trehalose is consistent with those of non-sea-salt Ca2+ and δ13C of total carbon with elevated levels during the Asian dust storm events. This study indicates that sugar compounds in atmospheric PM over East Asia can be derived from biomass burning, Asian dust, and primary biological aerosols such as fungal spores and pollen. Furthermore, this study supports the idea that sucrose could be used as a tracer for airborne pollen grains, and trehalose as a tracer for Asian dust outflow.

  10. Optical and microphysical properties of mineral dust and biomass burning aerosol observed over Warsaw on 10th July 2013

    NASA Astrophysics Data System (ADS)

    Janicka, Lucja; Stachlewska, Iwona; Veselovskii, Igor; Baars, Holger

    2016-04-01

    Biomass burning aerosol originating from Canadian forest fires was widely observed over Europe in July 2013. Favorable weather conditions caused long-term westward flow of smoke from Canada to Western and Central Europe. During this period, PollyXT lidar of the University of Warsaw took wavelength dependent measurements in Warsaw. On July 10th short event of simultaneous advection of Canadian smoke and Saharan dust was observed at different altitudes over Warsaw. Different origination of both air masses was indicated by backward trajectories from HYSPLIT model. Lidar measurements performed with various wavelength (1064, 532, 355 nm), using also Raman and depolarization channels for VIS and UV allowed for distinguishing physical differences of this two types of aerosols. Optical properties acted as input for retrieval of microphysical properties. Comparisons of microphysical and optical properties of biomass burning aerosols and mineral dust observed will be presented.

  11. Field Observation of Heterogeneous Formation of Secondary Organic Aerosols on Asian Mineral Dust Surfaces

    NASA Astrophysics Data System (ADS)

    Wang, G.

    2014-12-01

    This study investigated the heterogeneous formation mechanism of secondary organic aerosols (SOA) on dust surfaces by characterizing molecular compositions and size distributions of dicarboxylic acids, keto-carboxylic acids, a-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) in the urban atmosphere of Xi'an, China during dust storm periods and comparing with those in non-dust storm periods. In the presence of a dust storm, all the above mentioned SOA species in Xi'an are predominantly enriched on coarse particles (>2.1 µm). Oxalic acid well correlated with NO3- (r2=0.72, p<0.01) rather than SO42-. This phenomenon differs greatly from the observed particles during a non-dust storm period, which is characterized by an enrichment of the SOA on fine particles (<2.1 µm) with a strong correlation between C2 and SO42-. We propose a three-step formation pathway to explain these observations as follows. First, nitric acid and nitrogen oxides react with dust to form a liquid film on the surface via water vapor-absorption of calcium nitrate. Second, gaseous Gly and mGly partition into the aqueous-phase. Finally, the aqueous-phase Gly and mGly oxidize into glyoxylic acid (wC2), followed by a further oxidation into C2. To the best of our knowledge, we found for the first time the enrichments of glyoxal (Gly) and methylglyoxal (mGly) on dust surfaces. Our data indicate a more critical role of nitrate than sulfate in the heterogeneous formation process of SOA on dust surfaces. Mass ratio of C2 to wC2 was found to be higher in coarse particles than in fine particles during the dust storm events, which is due to low acidity condition of large particles that is favorable for conversion of wC2 to C2.

  12. Theoretical investigation on the role of mineral dust aerosol in atmospheric reaction: A case of the heterogeneous reaction of formaldehyde with NO2 onto SiO2 dust surface

    NASA Astrophysics Data System (ADS)

    Ji, Yuemeng; Wang, Honghong; Li, Guiying; An, Taicheng

    2015-02-01

    The role of mineral dusts on the heterogeneous reaction of formaldehyde with NO2 was investigated using a quantum chemical approach. SiO2 was selected as a model of mineral dust to investigate the heterogeneous reaction mechanism and kinetics because the mineral dust is comprised of ∼60% of SiO2. Compared with NO2, formaldehyde was easily adsorbed onto SiO2 model, indicating SiO2 was a sink for formaldehyde. Further data showed that the presence of SiO2 reduced the reaction barrier, but did not change reaction mechanism. The kinetics calculation using the canonical variational transition state theory plus small curvature tunneling correction showed that the presence of SiO2 could accelerate the atmospheric reaction rate of formaldehyde with NO2 to produce HONO. The effect of the altitudes was also considered, and the heterogeneous reaction rate decreased with increasing the altitude due to the atmospheric temperature decrease, suggesting that the degradation of atmospheric HCHO onto available mineral dusts might be competitive with the corresponding homogeneous reaction, especially in dusty urban and desert environments. This work can lay the foundation on the atmospheric heterogeneous reaction of VOCs, probe the role of mineral dust and establish the atmospheric transformation models, to better understand pollution mechanism.

  13. Separating Continental Mineral Dust from Cosmic Dust using Platinum Group Element Concentrations and Osmium Isotopes in Ancient Polar Ice

    NASA Astrophysics Data System (ADS)

    Seo, J. H.; Jackson, B.; Osterberg, E. C.; Sharma, M.

    2015-12-01

    The platinum group element (PGEs: Pt, Pd, Rh, Ir, Os, and Ru) accumulation in ancient polar archives have been argued to trace cosmic dust and "smoke" from larger meteors but the PGE concentration data lack specificity. For example, the extent to which the terrestrial volcanism/dust has contributed to the PGE inventory of polar ice cannot be readily evaluated. Since the Os isotope compositions (187Os/188Os ratio) of the terrestrial and extraterrestrial sources are distinctly different from each other, the PGE concentrations when combined with Os isotope composition have the potential to untangle contributions from these sources. Platinum group element concentration determinations in polar ice cores are highly challenging due to their extremely low concentrations (down to 10-15 g/g or fg/g). Here, a new procedure is presented that allows PGEs and Os isotope compositions to be determined from a ~50 g sample of polar ice. Decontaminated ice-melt is spiked with 101Ru, 106Pd, 190Os, 191Ir, and 198Pt and frozen at -20 °C in quartz-glass ampoules. A mixture of purified HNO3 and H2O2 is then added and the sample is heated to 300 °C at 128bar using a High Pressure Asher. This allows all spikes to be equilibrated with the sample PGEs and all Os species are oxidized to OsO4. The resulting OsO4 is extracted using distillation, purified, and measured using negative thermal ionization mass spectrometry. PGEs are then separated and purified using two stage column chromatography and their concentrations determined by isotope dilution using a triple quadruople inductively coupled plasma mass spectrometer coupled to an Apex de-solvation nebulizer. The developed method was applied to modern Greenland firn and snow. The PGE concentrations of the firn are 4.0 fg/g for Ir, 20 fg/g for Ru, 590 fg/g for Pt, 38 fg/g for Pd, and 1.3 fg/g for Os, while those of the snow are 3.0 fg/g for Ir, 53 fg/g for Ru, 360 fg/g for Pt, 32 fg/g for Pd, and 0.4 fg/g for Os, respectively. A comparison

  14. An empirical equation to estimate mineral dust concentrations from visibility observations in Northern Africa

    NASA Astrophysics Data System (ADS)

    Camino, C.; Cuevas, E.; Basart, S.; Alonso-Pérez, S.; Baldasano, J. M.; Terradellas, E.; Marticorena, B.; Rodríguez, S.; Berjón, A.

    2015-03-01

    This paper presents a new empirical equation relating horizontal visibility and PM10 dust concentrations. The new empirical equation (IZO-Eq) is derived from observations performed at the Izaña Atmospheric Observatory (IZO, 28.30°N, 16.49°W, 2367 m a.s.l., Tenerife, Spain), recorded during Saharan dust outbreaks from 2003 to 2010. A filter based on relative humidity, present-weather and aerosol optical properties is applied to identify dust events. IZO-Eq is validated in the Sahel region during the dry and wet seasons (2006-2008) using data from two PM10 monitoring stations from the African Monsoon Multidisciplinary Analysis (AMMA) International Project, and data from the nearest meteorological synoptic stations. The estimated PM10 derived from IZO-Eq is compared against that those obtained by other empirical equations and dust surface concentrations from NMMB/BSC-Dust model. IZO-Eq presents better performance than the other equations in both dry and wet seasons when compared with observed PM10 at two Sahelian sites. IZO-Eq is also able to reproduce the surface concentration variability simulated by NMMB/BSC-Dust. Above 10 km of horizontal visibility, empirical equations cannot be used to estimate PM10, since above this threshold equations estimate a nearly constant PM10 value, regardless of the visibility range. A comparison between the PM10 spatial distributions derived from visibility SYNOP observations through IZO-Eq, the modelled values from the NMMB/BSC-Dust model and aerosol optical depth (AOD) retrieved from MODIS is performed for the 2006-2008 period. The different spatial distributions present a rather good agreement among them as well as to reproduce the characteristic seasonal dust features over North Africa.

  15. Instituting a filtration/pressurization system to reduce dust concentrations in a control room at a mineral processing plant

    PubMed Central

    Noll, J.; Cecala, A.; Hummer, J.

    2016-01-01

    The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent. PMID:26834293

  16. Heterogeneous freezing of droplets with immersed surface modified mineral dust particles

    NASA Astrophysics Data System (ADS)

    Hartmann, Susan

    2010-05-01

    In the framework of the international measurement campaign FROST II (FReezing Of duST), the heterogeneous freezing of droplets with an immersed surface modified size-segregated mineral dust particles was investigated at LACIS (Leipzig Aerosol Cloud Interaction Simulator, Stratmann et al. 2004). The following measurements were done: LACIS, CFDC (Continuous Flow thermal gradient Diffusion Chamber, Rogers (1988)) and FINCH (Fast Ice Nucleus Chamber Counter, Bundke et al (2008)) were used to analyze the immersion freezing behavior of the treated Arizona Test Dust (ATD) particles at different temperature regimes. The ability to act as IN (Ice Nucleus) in the deposition nucleation mode was quantified by the PINC (Portable Ice Nucleation Chamber) and the CFDC instrument. AMS (Aerosol Mass Spectrometers, e.g. Schneider et al. (2005)) and ATOFMS (Aerosol Time-Of-Flight Mass Spectrometer) measurements were applied to determine particle composition. The hygroscopic growth and the critical super-saturations needed for droplet activation were determined by means of an H-TDMA (Humidity-Tandem Differential Mobility Analyzer) and CCN counter (Cloud Condensation Nucleus counter, Droplet Measurement Technologies, Roberts and Nenes (2005)). The 300 nm ATD particles were chemically and physically treated by coating with sulphuric acid (H2SO4, three different coating thicknesses) and ammonium sulphate ((NH4)2SO4) or by thermal treatment with a thermodenuder operating at 250°C. The H2SO4 coating modified the particles by reacting with particle material, forming soluble sulfates and therefore changing surface properties. AMS showed free H2SO4 only for thick H2SO4 coatings. In the heated section of the thermodenuder coating materials were evaporated partly and the surface properties of the particles were additionally altered. Uncoated particles and those coated with thin coatings of H2SO4, showed almost no hygroscopic growth. Particles coated with thicker coatings of H2SO4 and of (NH4

  17. Diagnostic evaluation of the Community Earth System Model in simulating mineral dust emission with insight into large-scale dust storm mobilization in the Middle East and North Africa (MENA)

    NASA Astrophysics Data System (ADS)

    Parajuli, Sagar Prasad; Yang, Zong-Liang; Lawrence, David M.

    2016-06-01

    Large amounts of mineral dust are injected into the atmosphere during dust storms, which are common in the Middle East and North Africa (MENA) where most of the global dust hotspots are located. In this work, we present simulations of dust emission using the Community Earth System Model Version 1.2.2 (CESM 1.2.2) and evaluate how well it captures the spatio-temporal characteristics of dust emission in the MENA region with a focus on large-scale dust storm mobilization. We explicitly focus our analysis on the model's two major input parameters that affect the vertical mass flux of dust-surface winds and the soil erodibility factor. We analyze dust emissions in simulations with both prognostic CESM winds and with CESM winds that are nudged towards ERA-Interim reanalysis values. Simulations with three existing erodibility maps and a new observation-based erodibility map are also conducted. We compare the simulated results with MODIS satellite data, MACC reanalysis data, AERONET station data, and CALIPSO 3-d aerosol profile data. The dust emission simulated by CESM, when driven by nudged reanalysis winds, compares reasonably well with observations on daily to monthly time scales despite CESM being a global General Circulation Model. However, considerable bias exists around known high dust source locations in northwest/northeast Africa and over the Arabian Peninsula where recurring large-scale dust storms are common. The new observation-based erodibility map, which can represent anthropogenic dust sources that are not directly represented by existing erodibility maps, shows improved performance in terms of the simulated dust optical depth (DOD) and aerosol optical depth (AOD) compared to existing erodibility maps although the performance of different erodibility maps varies by region.

  18. Molecular epidemiology of coal worker's pneumoconiosis: Application to risk assessment of oxidant and monokine generation by mineral dusts

    SciTech Connect

    Borm, P.J.; Meijers, J.M.; Swaen, G.M. )

    1990-01-01

    It is generally accepted that fibrotic lung diseases are mediated by macrophage-derived cytokines and growth factors. Basic research continues to find new factors involved in these disease processes to incorporate into new hypotheses. Two hypotheses implicitly generated by recent findings were tested in an epidemiologic approach among workers in coal mines. This approach is described as molecular epidemiology and is exemplified by two studies focused on different mechanistic aspects of coal workers' pneumoconiosis (CWP): antioxidants in red blood cells of miners with CWP and generation of tumor necrosis factor (TNF) by blood monocytes of miners with CWP. Most findings in the antioxidant study may merely be reflections of pulmonary inflammatory processes. Some data in the TNF study indicate, however, that TNF release is a risk factor for the development of lung fibrosis after prolonged exposure to coal mine dust.

  19. Airborne spectrophotometry of SN 1987A from 1.7 to 12.6 microns - Time history of the dust continuum and line emission

    NASA Technical Reports Server (NTRS)

    Wooden, Diane H.; Rank, David M.; Bregman, Jesse D.; Witteborn, Fred C.; Tielens, A. G. G. M.; Cohen, Martin; Pinto, Philip A.; Axelrod, Timothy S.

    1993-01-01

    Spectrophotometric observations of SN 1987A from the Kuiper Airborne Observatory are presented for five epochs at 60, 260, 415, 615, and 775 days after the explosion. The low-resolution (lambda/Delta lambda = 50-100) spectra of SN 1987A are combined with data from other wavelengths to model the continuum, subtract the continuum from the spectra to determine line strengths and reveal molecular bands, separate the atomic continuum radiation from the dust continuum, and derive constraints on the grain temperatures and optical depths. A scenario for the evolution of SN 1987A and that of the ejecta from which it arises is obtained on the basis of the analysis of the continuum emission.

  20. Assessment of MODIS-Derived Visible and Near-IR Aerosol Optical Properties and their Spatial Variability in the Presence of Mineral Dust

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Zhang, Q.; Schmid, B.; Russell, P. B.; Livingston, J. M.; Jonsson, H.; Remer, L. A.

    2006-01-01

    Mineral dust aerosol is among the most difficult aerosol species to measure quantitatively from space. In this paper, we evaluate MODIS retrievals of spectral aerosol optical depth (AOD) from the visible to the near-IR off the US West Coast using measurements taken by the NASA Ames Airborne Tracking Sunphotometer, AATS-14, during the EVE (Extended-MODIS-lambda Validation Experiment, 2004) campaign in April of 2004. In EVE, a total of 35 and 49 coincident over-ocean suborbital measurements at the nominal level-2 retrieval scale of 10 km x 10 km were collected for Terra and Aqua, respectively. For MODIS-Terra about 80% of the AOD retrievals are within the estimated uncertainty, DELTA tau = plus or minus 0.03 plus or minus 0.05 tau; this is true for both the visible (here defined to include 466-855 nm) and near-IR (here defined to include 1243-2119 nm) retrievals. For MODIS-Aqua about 45% of the AOD retrievals are within DELTA tau = plus or minus 0.03 plus or minus 0.05 tau; the fraction of near-IR retrievals that fall within this uncertainty range is about 27%. We found an rms difference of 0.71 between the sunphotometer snd MODIS-Aqua estimates of the visible (553-855 nm) Angstrom exponent, while the MODIS-Terra visible Angstrom exponents show an rms difference of only 0.29 when compared to AATS. The cause of the differences in performance between MODIS-Terra and MODIS-Aqua could be instrument calibration and needs to be explored further. The spatial variability of AOD between retrieval boxes as derived by MODIS is generally larger than that indicated by the sunphotometer data.

  1. Elevated Airborne Exposures of Teenagers to Manganese, Chromium, and Iron from Steel Dust and New York City’s Subway System

    PubMed Central

    CHILLRUD, STEVEN N.; EPSTEIN, DAVID; ROSS, JAMES M.; SAX, SONJA N.; PEDERSON, DEE; SPENGLER, JOHN D.; KINNEY, PATRICK L.

    2011-01-01

    There is increasing interest in potential health effects of airborne exposures to hazardous air pollutants at relatively low levels. This study focuses on sources, levels, and exposure pathways of manganese, chromium, and iron among inner-city high school students in New York City (NYC) and the contribution of subways. Samples of fine particulate matter (PM2.5) were collected during winter and summer over 48 h periods in a variety of settings including inside homes, outdoors, and personal samples (i.e., sampling packs carried by subjects). PM2.5 samples were also collected in the NYC subway system. For NYC, personal samples had significantly higher concentrations of iron, manganese, and chromium than did home indoor and ambient samples. The ratios and strong correlations between pairs of elements suggested steel dust as the source of these metals for a large subset of the personal samples. Time–activity data suggested NYC subways as a likely source of these elevated personal metals. In duplicate PM2.5 samples that integrated 8 h of underground subway exposure, iron, manganese, and chromium levels (>2 orders of magnitude above ambient levels) and their ratios were consistent with the elevated personal exposures. Steel dust in the NYC subway system was the dominant source of airborne exposures to iron, manganese, and chromium for many young people enrolled in this study, with the same results expected for other NYC subway riders who do not have occupational exposures to these metals. However, there are currently no known health effects at the exposure levels observed in this study. PMID:14968857

  2. Atmospheric dry deposition of mineral dust to the Gulf of Aqaba, Red Sea: rate and trace elements.

    PubMed

    Al-Taani, Ahmed A; Rashdan, Maen; Khashashneh, Safaa

    2015-03-15

    Atmospheric dry deposition to the Gulf of Aqaba (GoA) is particularly a significant source of trace elements. Amid desert regions, the Gulf receives high fluxes of mineral dust with an average rate of 34.68 g/m(2)/year measured in 2012. Patterns of dry deposition showed seasonal fluxes with highest rates observed in summer and lowest in winter. The observed variations were attributed to wind direction, timing of deposition and sources of dust. The average dry fluxes of Al, Fe, Mn, Cr, Cd, Cu, Pb and Zn were 551, 440, 10.29, 1.42, 0.04, 0.68, 1.42 and 4.02 mg/m(2)/year, respectively. While the dry deposition fluxes were enriched in Cd, Cu, Pb and Zn indicating their dominant anthropogenic sources, they appeared to be less influenced compared to the neighboring Mediterranean area and other industrial countries, but were similar to or slightly higher than those in remote areas. The enrichment values for Fe and Mn were low, consistent with their crustal origin. The fluxes of all elements suggested the impacts of both crustal (due to climate change) and anthropogenic sources became stronger in this region. The Sahara dust was probably a minor contributor to dry deposition in the GoA.

  3. Investigating the Heterogeneous Interaction of VOCs with Natural Atmospheric Particles: Adsorption of Limonene and Toluene on Saharan Mineral Dusts.

    PubMed

    Romanías, Manolis N; Ourrad, Habib; Thévenet, Frédéric; Riffault, Véronique

    2016-03-01

    The heterogeneous interaction of limonene and toluene with Saharan dusts was investigated under dark conditions, pressure of 1 atm, and temperature 293 K. The mineral dust samples were collected from six different regions along the Sahara desert, extending from Tunisia to the western Atlantic coastal areas of Morocco, and experiments were carried out with the smallest sieved fractions, that is, inferior to 100 μm. N2 sorption measurements, granulometric analysis, and X-ray fluorescence and diffraction (XRF and XRD) measurements were conducted to determine the physicochemical properties of the particles. The chemical characterization showed that dust originating from mideastern Sahara has a significantly higher SiO2 content (∼ 82%) than dust collected from the western coastal regions where the SiO2 relative abundance was ∼ 50%. A novel experimental setup combining diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), selected-ion flow-tube mass spectrometry (SIFT-MS), and long path transmission Fourier transform infrared spectroscopy (FTIR) allowed us to follow both the adsorbed and gas phases. The kinetic adsorption/desorption measurements were performed using purified dry air as bath gas, exposing each dust surface to 10 ppm of the selective volatile organic compound (VOC). The adsorption of limonene was independent of the SiO2 content, given the experimental uncertainties, and the coverage measurements ranged between (10 and 18) × 10(13) molecules cm(-2). Experimental results suggest that other metal oxides that could possibly influence dust acidity may enhance the adsorption of limonene. On the contrary, in the case of toluene, the adsorption capacities of the Saharan samples increased with decreasing SiO2 content; however, the coverage measurements were significantly lower than those of limonene and ranged between (2 and 12) × 10(13) molecules cm(-2). Flushing the surface with purified dry air showed that VOC desorption is not a

  4. Investigating the Heterogeneous Interaction of VOCs with Natural Atmospheric Particles: Adsorption of Limonene and Toluene on Saharan Mineral Dusts.

    PubMed

    Romanías, Manolis N; Ourrad, Habib; Thévenet, Frédéric; Riffault, Véronique

    2016-03-01

    The heterogeneous interaction of limonene and toluene with Saharan dusts was investigated under dark conditions, pressure of 1 atm, and temperature 293 K. The mineral dust samples were collected from six different regions along the Sahara desert, extending from Tunisia to the western Atlantic coastal areas of Morocco, and experiments were carried out with the smallest sieved fractions, that is, inferior to 100 μm. N2 sorption measurements, granulometric analysis, and X-ray fluorescence and diffraction (XRF and XRD) measurements were conducted to determine the physicochemical properties of the particles. The chemical characterization showed that dust originating from mideastern Sahara has a significantly higher SiO2 content (∼ 82%) than dust collected from the western coastal regions where the SiO2 relative abundance was ∼ 50%. A novel experimental setup combining diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), selected-ion flow-tube mass spectrometry (SIFT-MS), and long path transmission Fourier transform infrared spectroscopy (FTIR) allowed us to follow both the adsorbed and gas phases. The kinetic adsorption/desorption measurements were performed using purified dry air as bath gas, exposing each dust surface to 10 ppm of the selective volatile organic compound (VOC). The adsorption of limonene was independent of the SiO2 content, given the experimental uncertainties, and the coverage measurements ranged between (10 and 18) × 10(13) molecules cm(-2). Experimental results suggest that other metal oxides that could possibly influence dust acidity may enhance the adsorption of limonene. On the contrary, in the case of toluene, the adsorption capacities of the Saharan samples increased with decreasing SiO2 content; however, the coverage measurements were significantly lower than those of limonene and ranged between (2 and 12) × 10(13) molecules cm(-2). Flushing the surface with purified dry air showed that VOC desorption is not a

  5. Proxies and measurement techniques for mineral dust in Antarctic ice cores.

    PubMed

    Ruth, Urs; Barbante, Carlo; Bigler, Matthias; Delmonte, Barbara; Fischer, Hubertus; Gabrielli, Paolo; Gaspari, Vania; Kaufmann, Patrik; Lambert, Fabrice; Maggi, Valter; Marino, Federica; Petit, Jean-Robert; Udisti, Roberto; Wagenbach, Dietmar; Wegner, Anna; Wolff, Eric W

    2008-08-01

    To improve quantitative interpretation of ice core aeolian dust records, a systematic methodological comparison was made. This involved methods for water-insoluble particle counting (Coulter counter and laser-sensing particle detector), soluble ion analysis (ion chromatography and continuous flow analysis), elemental analysis (inductively coupled plasma mass spectroscopy at pH 1 and after full acid digestion), and water-insoluble elemental analysis (proton induced X-ray emission). Antarctic ice core samples covering the last deglaciation from the EPICA Dome C (EDC) and the EPICA Dronning Maud Land (EDML) cores were used. All methods correlate very well among each other, but the ratios of glacial age to Holocene concentrations, which are typically a factor approximately 100, differ between the methods by up to a factor of 2 with insoluble particles showing the largest variability. The recovery of ICP-MS measurements depends on the digestion method and is differentfor different elements and during different climatic periods. EDC and EDML samples have similar dust composition, which suggests a common dust source or a common mixture of sources for the two sites. The analyzed samples further reveal a change of dust composition during the last deglaciation.

  6. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  7. Levels and risk assessment for humans and ecosystems of platinum-group elements in the airborne particles and road dust of some European cities.

    PubMed

    Gómez, B; Palacios, M A; Gómez, M; Sanchez, J L; Morrison, G; Rauch, S; McLeod, C; Ma, R; Caroli, S; Alimonti, A; Petrucci, E; Bocca, B; Schramel, P; Zischka, M; Petterson, C; Wass, U

    2002-11-01

    Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3-13.1 pg m(-3). The ring roads of these cities have values in the range 4.1-17.7 pg m(-3). In Munich, a lower Pt content was found in airborne particles (4.1 pg m(-3)). The same tendency has been noted for downtown Rh, with contents in the range 2.2-2.8 pg m(-3), and in the range 0.8-3.0 and 0.3 pg m(-3) for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles

  8. Effects of Saharan Mineral Dust Aerosols on the Dynamics of an Idealized African Easterly Jet-African Easterly Wave System over North Africa

    NASA Astrophysics Data System (ADS)

    Grogan, Dustin Francis Phillip

    The central objective of this work is to examine the direct radiative effects of Saharan mineral dust aerosols on the dynamics of African easterly waves (AEWs) and the African easterly jet (AEJ). Achieving this objective is built around two tasks that use the Weather Research and Forecasting (WRF) model coupled to an online dust model (WRF-dust model). The first task (Chapter 2) examines the linear dynamics of AEWs; the second task (Chapter 3) examines the nonlinear evolution of AEWs and their interactions with the AEJ. In Chapter 2, the direct radiative effects of dust on the linear dynamics of AEWs are examined analytically and numerically. The analytical analysis combines the thermodynamic equation with a dust continuity equation to form an expression for the generation of eddy available potential energy (APE) by the dust field. The generation of eddy APE is a function of the transmissivity and spatial gradients of the dust, which are modulated by the Doppler-shifted frequency. The expression predicts that for a fixed dust distribution, the wave response will be largest in regions where the dust gradients are maximized and the Doppler-shifted frequency vanishes. The numerical analysis calculates the linear dynamics of AEWs using zonally averaged basic states for wind, temperature and dust consistent with summertime conditions over North Africa. For the fastest growing AEW, the dust increases the growth rate from ~15% to 90% for aerosol optical depths ranging from tau=1.0 to tau=2.5. A local energetics analysis shows that for tau=1.0, the dust increases the maximum barotropic and baroclinic energy conversions by ~50% and ~100%, respectively. The maxima in the generation of APE and conversions of energy are co-located and occur where the meridional dust gradient is maximized near the critical layer, i.e., where the Doppler-shifted frequency is small, in agreement with the prediction from the analytical analysis. In Chapter 3, the direct radiative effects of dust

  9. Mineral dust archive in Taylor Dome ice core as evidence for shifting coastal east Antarctic climate during the LGM-Holocene transition

    NASA Astrophysics Data System (ADS)

    Aarons, S. M.; Aciego, S.; Gabrielli, P.; Delmonte, B.; Koornneef, J.; Bouman, C.; Wegner, A.

    2014-12-01

    Ice cores from ice sheets in Antarctica provide valuable records of past climates encompassing hundreds of thousands of years. Chemical and mineralogical characterization of aerosol mineral particles (dust) transported through the atmosphere and deposited on ice sheets and glaciers provide insight into the regional and global climate conditions during a time period. Elemental and isotopic analysis of dust entrapped in ice aids in determining provenance, with variations signifying changes in dust production, sources and transport pathways, indicating an evolving local and/or global climate. We present radiogenic isotope and elemental compositions of insoluble dust entrained in a coastal Antarctic ice core during the transition from the Last Glacial Maximum (LGM) to the Holocene. A series of 15 samples from the Taylor Dome ice core, 113-391 m in depth covering a time period of 1.8-31.5 ka were analyzed using traditional Thermal Ionization Mass Spectrometry (TIMS) equipped with 10-11 Ohm resistors (87Sr/86Sr) and 10-13 Ohm resistors (143Nd/144Nd). We determined trace (TE) and rare earth element (REE) concentrations by Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP-SFMS) and dust concentration and size distribution by Coulter Counter. The radiogenic isotopic compositions of glacial dust agrees with previously measured Antarctic dust: 87Sr/86Sr= 0.7052 - 0.7124 and ɛNd= -0.9 - -4.7, whereas Holocene dust displays a broader range from 87Sr/86Sr= 0.7054 - 0.7163 and ɛNd= -0.9 - -7.1, suggesting a shift from globally transported dust to more variable local input following the LGM to Holocene transition. The REE and TE concentrations display typical East Antarctic ice core dust patterns. The average dust particle diameter increases from ~1.8 to ~3 μm with decreasing depositional age, supporting the alteration in dust transport mechanism hypothesis. Our results display dust concentrations of >500 and <15 ppb during glacial and interglacial periods

  10. Global potential of dust devil occurrence

    NASA Astrophysics Data System (ADS)

    Jemmett-Smith, Bradley; Marsham, John; Knippertz, Peter; Gilkeson, Carl

    2014-05-01

    Mineral dust is a key constituent in the climate system. Airborne mineral dust forms the largest component of the global aerosol budget by mass and subsequently affects climate, weather and biogeochemical processes. There remains large uncertainty in the quantitative estimates of the dust cycle. Dry boundary-layer convection serves as an effective mechanism for dust uplift, typically through a combination of rotating dust devils and non-rotating larger and longer-lived convective plumes. These microscale dry-convective processes occur over length scales of several hundred metres or less. They are difficult to observe and model, and therefore their contribution to the global dust budget is highly uncertain. Using an analytical approach to extrapolate limited observations, Koch and Renno (2006) suggest that dust devils and plumes could contribute as much as 35%. Here, we use a new method for quantifying the potential of dust devil occurrence to provide an alternative perspective on this estimate. Observations have shown that dust devil and convective plume occurrence is favoured in hot arid regions under relatively weak background winds, large ground-to-air temperature gradients and deep dry convection. By applying such known constraints to operational analyses from the European Centre for Medium Range Weather Forecasts (ECMWF), we provide, to the best of the authors' knowledge, the first hourly estimates of dust devil occurrence including an analysis of sensitivity to chosen threshold uplift. The results show the expected diurnal variation and allow an examination of the seasonal cycle and day-to-day variations in the conditions required for dust devil formation. They confirm that desert regions are expected to have by far the highest frequency of dry convective vortices, with winds capable of dust uplift. This approach is used to test the findings of Koch and Renno (2006). Koch J., Renno N. (2006). The role of convective plumes and vortices on the global aerosol

  11. Using NASA EOS in the Arabian and Saharan Deserts to Examine Dust Particle Size and Spectral Signature of Aerosols

    NASA Astrophysics Data System (ADS)

    Brenton, J. C.; Keeton, T.; Barrick, B.; Cowart, K.; Cooksey, K.; Florence, V.; Herdy, C.; Luvall, J. C.; Vasquez, S.

    2012-12-01

    Exposure to high concentrations of airborne particulate matter can have adverse effects on the human respiratory system. Ground-based studies conducted in Iraq have revealed the presence of potential human pathogens in airborne dust. According to the Environmental Protection Agency (EPA), airborne particulate matter below 2.5μm (PM2.5) can cause long-term damage to the human respiratory system. Given the relatively high incidence of new-onset respiratory disorders experienced by US service members deployed to Iraq, this research offers a new glimpse into how satellite remote sensing can be applied to questions related to human health. NASA's Earth Observing System (EOS) can be used to determine spectral characteristics of dust particles, the depth of dust plumes, as well as dust particle sizes. Comparing dust particle size from the Sahara and Arabian Deserts gives insight into the composition and atmospheric transport characteristics of dust from each desert. With the use of NASA SeaWiFS DeepBlue Aerosol, dust particle sizes were estimated using Angström exponent. Brightness Temperature Difference (BTD) equation was used to determine the distribution of particle sizes, the area of the dust storm, and whether silicate minerals were present in the dust. The Moderate-resolution Imaging Spectroradiometer (MODIS) on Terra satellite was utilized in calculating BTD. Minimal research has been conducted on the spectral characteristics of airborne dust in the Arabian and Sahara Deserts. Mineral composition of a dust storm that occurred 17 April 2008 near Baghdad was determined using imaging spectrometer data from the Jet Propulsion Laboratory Spectral Library and EO-1 Hyperion data. Mineralogy of this dust storm was subsequently compared to that of a dust storm that occurred over the Bodélé Depression in the Sahara Desert on 7 June 2003.

  12. Laboratory measurements of contact nucleation by mineral dusts, bacteria, and soluble salts

    NASA Astrophysics Data System (ADS)

    Niehaus, Joseph

    We present results from experiments that emulate atmospheric ice nucleation by aerosols. We have refined experimental techniques to improve measurements of ice forming nuclei in the contact mode. Our results show that atmospherically relevant dusts such as kaolinite, feldspar, rhyolitic ash, and Arizona Test Dust have efficiencies in the contact mode that are higher than the immersion mode. Experiments with bacteria show that biological material has the potential to contribute significantly to ice concentrations, but has large variability. By choosing a soluble compound as an ice nucleus, we are able to place bounds on the timescale for contact freezing and estimate the nucleation time from impact to be 10--9 seconds. Finally, we conclude that the contact mode can increase nucleation rates in two ways: by the creation of a triple-phase line with an insoluble nucleus, or by the collision event.

  13. Small airways involvement in coal mine dust lung disease.

    PubMed

    Long, Joshua; Stansbury, Robert C; Petsonk, Edward L

    2015-06-01

    Inhalation of coal mine dust results in a spectrum of symptoms, dysfunction, and pathological changes in the respiratory tract that collectively have been labeled coal mine dust lung disease. Recent reports from periodic health surveillance among underground and surface coal miners in the United States have demonstrated an increasing prevalence and severity of dust diseases, and have also documented that some miners experience rapid disease progression. The coal macule is an inflammatory lesion associated with deposited dust, and occurs in the region of the most distal conducting airways and proximal respiratory bronchioles. Inflammatory changes in the small airways have long been recognized as the signature lung pathology among coal miners. Human and laboratory studies have suggested oxidant injury, and increased recruitment and activity of macrophages play important roles in dust-induced lung injury. However, the functional importance of the small airway changes was debated for many years. We reviewed published literature that documents a pervasive occurrence of both physiologic and structural abnormalities in small airways among coal miners and other workers exposed to airborne particulates. There is increasing evidence supporting an important association of abnormalities in the small peripheral airways with the development of respiratory symptoms, deficits in spirometry values, and accelerated declines in ventilatory lung function. Pathologic changes associated with mineral dust deposition in the small airways may be of particular importance in contemporary miners with rapidly progressive respiratory impairment.

  14. Composition, size distribution, optical properties and radiative effects of re-suspended local mineral dust of Rome area by individual-particle microanalysis and radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Pietrodangelo, A.; Salzano, R.; Bassani, C.; Pareti, S.; Perrino, C.

    2015-05-01

    New information on the PM10 mineral dust from site-specific (Rome area, Latium) outcropped rocks, and on the microphysics, optical properties and radiative effects of mineral dust at local level were gained in this work. A multi-disciplinary approach was used, based on individual-particle scanning electron microscopy with X-ray energy-dispersive microanalysis (SEM XEDS), X-ray diffraction (XRD) analysis of dust, size distribution of mineral particles, and radiative transfer modelling (RTM).The mineral composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals and one exclusively composed of calcite. The first is obtained from volcanic lithotypes, the second from travertine or limestones; lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones of Rome area. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are evidenced by the diversity of volume distributions, within either dust types, or mineral species. Further differences are observed between volume distributions of calcite from travertine (natural source) and from road dust (anthropic source), specifically on the width, shape and enrichment of the fine fraction (unimodal at 5 μm a.d. for travertine, bimodal at 3.8 and 1.8 μm a.d. for road dust). Log-normal probability density functions of volcanics and travertine dusts affect differently the single scattering albedo (SSA) and the asymmetry parameter (g) in the VISible and Near Infrared (NIR) regions, depending also on the absorbing/non-absorbing character of volcanics and travertine, respectively. The downward component of the BOA solar irradiance simulated by RTM for a volcanics-rich or travertine-rich atmosphere shows that volcanics contribution to the solar

  15. Coordinated Analyses of Mineral-organic Matter Associations in Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Nakamura-Messenger, K.; Herzog, G. F.; Smith, T.; Keller, L. P.; Flynn, G. J.; Khodja, H.; Taylor, S.; Wirick, S.; Messenger, S.

    2012-01-01

    Little is known about the timing and processes involved in the incorporation of organic matter with inorganic materials in early Solar System bodies. Recently, X-ray absorption near-edge spectroscopy (XANES) studies showed carbon-rich rims surrounding individual mineral grains in anhydrous IDPs [1,2]. These carbonaceous rims are believed to have formed prior to parent body formation and likely served to bond mineral grains during accretion into larger aggregates. We are exploring the nature of these carbonaceous rims through coordinated analyses of their chemistry, mineralogy, spectroscopy and isotopic characteristics. Here we report our preliminary mineralogical observations.

  16. [Hygienic regulation of dust of magnesium-silicate minerals and fireproof materials].

    PubMed

    Kislitsina, N S; Privalova, L I; Sharapova, N E

    1993-01-01

    Chronic experiments on rats showed that the dust of silicomagnesian refractory and dunite (a raw material for refractory production) extracted in Kytlym differ insignificantly in fibrogenic activity, but rank below the quartzite extracted in Pervouralsk (MAC-1 mg/cu m). The short study analyzing the cytologic changes of bronchoalveolar lavage determined the cytotoxicity of silicomagnesian refractory and 4 other types of dunite. The estimated cytotoxicity also ranked below that of quartzite from Pervouralsk. The MAC equal to 4 mg/cu m was suggested for the group of aerosols produced by dunite and silicomagnesian refractories. These aerosols are assigned to the 3rd jeopardy class and possess basically fibrogenic activity.

  17. [Hygienic regulation of dust of magnesium-silicate minerals and fireproof materials].

    PubMed

    Kislitsina, N S; Privalova, L I; Sharapova, N E

    1993-01-01

    Chronic experiments on rats showed that the dust of silicomagnesian refractory and dunite (a raw material for refractory production) extracted in Kytlym differ insignificantly in fibrogenic activity, but rank below the quartzite extracted in Pervouralsk (MAC-1 mg/cu m). The short study analyzing the cytologic changes of bronchoalveolar lavage determined the cytotoxicity of silicomagnesian refractory and 4 other types of dunite. The estimated cytotoxicity also ranked below that of quartzite from Pervouralsk. The MAC equal to 4 mg/cu m was suggested for the group of aerosols produced by dunite and silicomagnesian refractories. These aerosols are assigned to the 3rd jeopardy class and possess basically fibrogenic activity. PMID:7921832

  18. Chemical fate and settling of mineral dust in surface seawater after atmospheric deposition observed from dust seeding experiments in large mesocosms

    NASA Astrophysics Data System (ADS)

    Desboeufs, K.; Leblond, N.; Wagener, T.; Bon Nguyen, E.; Guieu, C.

    2014-10-01

    We report here the elemental composition of sinking particles in sediment traps and in the water column following four artificial dust seeding experiments (each representing a flux of 10 g m-2). Dry or wet dust deposition were simulated during two large mesocosms field campaigns that took place in the coastal water of Corsica (NW Mediterranean Sea) representative of oligotrophic conditions. The dust additions were carried out with fresh or artificially aged dust (i.e., enriched in nitrate and sulfate by mimicking cloud processing) for various biogeochemical conditions, enabling us to test the effect of these parameters on the chemical composition and settling of dust after deposition. The rates and mechanisms of total mass, particulate organic carbon (POC) and chemical elements (Al, Ba, Ca, Co, Cu, Fe, K, Li, Mg, Mn, Mo, N, Nd, P, S, Sr and Ti) transfer from the mesocosm surface to the sediment traps installed at the base of the mesocosms after dust deposition show that (1) 15% of the initial dust mass was dissolved in the water column in the first 24 h after seeding. Except for Ca, S and N, the elemental composition of dust particles was constant during their settling, showing the relevance of using interelemental ratios, such as Ti/Al as proxy of lithogenic fluxes. (2) Whatever the type of seeding (using fresh dust to simulate dry deposition or artificially aged dust to simulate wet deposition), the particulate phase both in the water column and in the sediment traps was dominated by dust particles. (3) Due to the high Ba content in dust, Ba/Al cannot be used as productivity proxy in the case of high dust input in the sediment traps. Instead, our data suggests that the ratio Co/Al could be a good productivity proxy in this case. (4) After 7 days, between 30 and 68% of added dust was still in suspension in the mesocosms. This difference in the dust settling was directly associated with a difference in POC export, since POC fluxes were highly correlated to dust

  19. Effects of Palagonitic Dust Coatings on Thermal Emission Spectra of Rocks and Minerals: Implications for Mineralogical Characterization of the Martian Surface by MGS-TES

    NASA Technical Reports Server (NTRS)

    Graff, T. G.; Morris, R.; Christensen, P.

    2001-01-01

    Thermal emission measurements on dust-coated rocks and minerals show that a 300 5m thick layer is required to mask emission from the substrate and that non-linear effects are present. Additional information is contained in the original extended abstract.

  20. Effects of Palagonitic Dust Coatings on Visible, Near-IR, and Mossbauer Spectra of Rocks and Minerals: Implication for Mineralogical Remote Sensing of Mars

    NASA Technical Reports Server (NTRS)

    Morris, R.; Graff, T. G.; Shelfer, T. D.; Bell, J. F., III

    2001-01-01

    Visible, near-IR, and Mossbauer measurements on dust coated rocks and minerals show that a 300 5m thick layer is required to obscure the substrate for VNIR measurements and that a greater than 2000-micron-thick layer is required to obscure the substrate for Mossbauer measurements. Additional information is contained in the original extended abstract.

  1. Observation of the simultaneous transport of Asian mineral dust aerosols with anthropogenic pollutants using a POPC during a long-lasting dust event in late spring 2014

    NASA Astrophysics Data System (ADS)

    Pan, Xiaole; Uno, Itsushi; Hara, Yukari; Kuribayashi, Masatoshi; Kobayashi, Hiroshi; Sugimoto, Nobuo; Yamamoto, Shigekazu; Shimohara, Takaaki; Wang, Zifa

    2015-03-01

    We observed a long-lasting dust event from 25 May to 2 June 2014, using a polarization optical particle counter (POPC). The transport of dust plumes over East Asia was verified on the basis of observations of Moderate Resolution Imaging Spectroradiometer, a lidar network, and surface synoptic observation stations. Mixing of dust and anthropogenic pollutants was investigated according to the variation in the depolarization ratio as a function of particle size. The nonsphericity of dust particles varied due to the impact of anthropogenic pollutants on their pathway. In the coarse mode, dust particles always had a clear nonspherical configuration, although large amounts of nitrate were also present. Supermicron particles are occasionally present in a spherical configuration, possibly due to the complex mixing of natural dust and anthropogenic particles. Statistically, ~64% of the total nitrate mass was deemed to be transported from outside of Japan due to a trapping effect in the dust plume.

  2. Laboratory-generated mixtures of mineral dust particles with biological substances: characterization of the particle mixing state and immersion freezing behavior

    NASA Astrophysics Data System (ADS)

    Augustin-Bauditz, Stefanie; Wex, Heike; Denjean, Cyrielle; Hartmann, Susan; Schneider, Johannes; Schmidt, Susann; Ebert, Martin; Stratmann, Frank

    2016-05-01

    Biological particles such as bacteria, fungal spores or pollen are known to be efficient ice nucleating particles. Their ability to nucleate ice is due to ice nucleation active macromolecules (INMs). It has been suggested that these INMs maintain their nucleating ability even when they are separated from their original carriers. This opens the possibility of an accumulation of such INMs in soils, resulting in an internal mixture of mineral dust and INMs. If particles from such soils which contain biological INMs are then dispersed into the atmosphere due to wind erosion or agricultural processes, they could induce ice nucleation at temperatures typical for biological substances, i.e., above -20 up to almost 0 °C, while they might be characterized as mineral dust particles due to a possibly low content of biological material. We conducted a study within the research unit INUIT (Ice Nucleation research UnIT), where we investigated the ice nucleation behavior of mineral dust particles internally mixed with INM. Specifically, we mixed a pure mineral dust sample (illite-NX) with ice active biological material (birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). A very important topic concerning the investigations presented here as well as for atmospheric application is the characterization of the mixing state of aerosol particles. In the present study we used different methods like single-particle aerosol mass spectrometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), and a Volatility-Hygroscopicity Tandem Differential Mobility Analyser (VH-TDMA) to investigate the mixing state of our generated aerosol. Not all applied methods performed similarly well in detecting small amounts of biological material on the mineral dust particles. Measuring the hygroscopicity/volatility of the mixed particles with the VH-TDMA was the most

  3. Quaternary dust sources on the Chinese Loess Plateau: a view from single zircon grains, heavy minerals and quartz luminescence

    NASA Astrophysics Data System (ADS)

    Stevens, T.; Carter, A.; Vermeesch, P.; Bird, A.; Rittner, M.; Lu, H.; Andò, S.; Garzanti, E.; Nie, J.; Adamiec, G.; Zeng, L.; Zhang, H.; Xu, Z.

    2013-12-01

    The origin of loess deposits on the Chinese Loess Plateau (CLP), one of the most valuable Cenozoic climate archives on land, is the subject of considerable debate. A large number of sources have been proposed for the vast quantity of dust that forms the up to 400 m thick loess sequences that cover the c. 640,000 km2 the CLP, including deserts, alluvial fans and mountain regions. There is also debate over whether sources shift across the CLP, within loess units, between units and across the Quaternary/Pliocene boundary. Furthermore, the role of river systems in sediment supply to the CLP has not previously been substantively addressed. Geochemical analysis of bulk sediment from loess is limited by mixing of different source influences and so here we apply a variety of techniques to Quaternary sequences on the CLP. We use single-grain based techniques on zircons and heavy mineral analyses in an attempt to discriminate between potential multiple sources and to test the influence of proximal deserts and major rivers on CLP dust. In addition, we utilise information from detailed optically stimulated luminescence dating of quartz from loess to identify rapid shifts in source region on the CLP. Provenance signatures from samples from the eastern Mu Us and the Tengger deserts can be explained by local sources and recycling of the underlying Cretaceous rock. However, the western Mu Us desert as well as Quaternary loess shows different zircon U-Pb age spectra and heavy mineral distributions, indicative of strong influence from northeastern Tibet. Further, samples from the Yellow River are close to identical to these western Mu Us samples and crucially, also to Quaternary samples from the Loess Plateau. This suggests that the Tibetan-derived sediments are unlikely to have been transported from Tibet by wind, but rather may have been delivered by the Yellow River. This provides the first evidence of a possible genetic link between the Yellow River and the CLP. However, there

  4. Analysis of In-Situ of Ozone Measurements in Saharan Mineral Dust during AEROSE Cruises

    NASA Astrophysics Data System (ADS)

    Roper, E. D.; Morris, V. R.; Nalli, N. R.; Joseph, E.

    2012-12-01

    The trans-Atlantic Aerosol and Oceanographic Science Expeditions (AEROSE) are a series of experiments that began in 2004 and take place in the tropical Atlantic Ocean. AEROSE collects a unique set of critical measurements to characterize the microphysical and chemical evolution of the Saharan dust aerosols during long-range transport. Continuous in-situ surface level measurements over the tropical Atlantic allows for accurate determination of lower tropospheric ozone concentrations, and its effects on the regional environment and climate that may be used to validate satellite observations. Ozone is instrumental in regulating the atmosphere's oxidizing capacity and can influence background levels of trace chemical species which affect the composition of the atmosphere and create climatic variations. Several studies have shown that ozone concentrations diminish with increased loading of dust particles from the Sahara. Current theories indicate that decomposition of ozone may be due to NOx titrations, decreased radiation, photocatalysis, interactions with organics, or heterogeneous reactions. In effort to understand the response of marine boundary layer ozone with coarse aerosols, analyses of ozone concentrations and aerosol correlations found in dusty Saharan air masses from various cruises will be presented.

  5. Mineral dust and cell recovery from the bronchoalveolar lavage of healthy Vermont granite workers.

    PubMed

    Christman, J W; Emerson, R J; Graham, W G; Davis, G S

    1985-08-01

    We characterized the bronchoalveolar lavage (BAL) from healthy Vermont granite workers to investigate the pulmonary response to a chronic exposure to an injurious agent. Nine granite workers with 4 to 36 yr of employment in the industry and 27 unexposed volunteers were normal by history, physical examination, electrocardiogram, blood count, spirometry, and chest radiograph. Lavage cell recovery and percent neutrophils were not different. Lymphocyte recovery in BAL was increased in the granite-exposed population. Granite dust was present within the majority of alveolar macrophages from granite workers compared with those from control subjects, as determined by polarizing light microscopy and confirmed by scanning electron microscopy with X-ray energy spectrometry. There were no differences in phagocytic function or viability of macrophages from granite workers compared with those from unexposed volunteers. We conclude that in exposed populations, granite dust can be detected and semiquantitated in lavage specimens within the alveolar macrophages, macrophage function is preserved, and the response to this exposure involves an influx of lymphocytes.

  6. Alteration mineral mapping and metallogenic prediction using CASI/SASI airborne hyperspectral data in Mingshujing area of Gansu Province, NW China

    NASA Astrophysics Data System (ADS)

    Sun, Yu; Zhao, Yingjun; Qin, Kai; Tian, Feng

    2016-04-01

    Hyperspectral remote sensing is a frontier of remote sensing. Due to its advantage of integrated image with spectrum, it can realize objects identification, superior to objects classification of multispectral remote sensing. Taken the Mingshujing area in Gansu Province of China as an example, this study extracted the alteration minerals and thus to do metallogenic prediction using CASI/SASI airborne hyperspectral data. The Mingshujing area, located in Liuyuan region of Gansu Province, is dominated by middle Variscan granites and Indosinian granites, with well developed EW- and NE-trending faults. In July 2012, our project team obtained the CASI/SASI hyperspectral data of Liuyuan region by aerial flight. The CASI hyperspectral data have 32 bands and the SASI hyperspectral data have 88 bands, with spectral resolution of 15nm for both. The hyperspectral raw data were first preprocessed, including radiometric correction and geometric correction. We then conducted atmospheric correction using empirical line method based on synchronously measured ground spectra to obtain hyperspectral reflectance data. Spectral dimension of hyperspectral data was reduced by the minimum noise fraction transformation method, and then purity pixels were selected. After these steps, image endmember spectra were obtained. We used the endmember spectrum election method based on expert knowledge to analyze the image endmember spectra. Then, the mixture tuned matched filter (MTMF) mapping method was used to extract mineral information, including limonite, Al-rich sericite, Al-poor sericite and chlorite. Finally, the distribution of minerals in the Mingshujing area was mapped. According to the distribution of limonite and Al-rich sericite mapped by CASI/SASI hyperspectral data, we delineated five gold prospecting areas, and further conducted field verification in these areas. It is shown that there are significant gold mineralized anomalies in surface in the Baixianishan and Xitan prospecting

  7. Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India.

    NASA Astrophysics Data System (ADS)

    Sharma, Disha; Kulshrestha, Umesh

    Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India. The Critical Load approach alongwith integrated assessment models has been used in the European nations for policy formations to reduce acidic emissions. This unique approach was applied to assess the of vulnerability of natural systems to the present day atmospheric pollution scenario. The calculated values of critical loads of sulphur ( 225 - 275 eq/ha/yr) and nitrogen (298 - 303 eq/ha/yr), for the soil system in Delhi, were calculated with respect to Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S) = 26.40 eq/ha/yr) and nitrogen (PL(N) = 36.51 eq/ha/yr) were found to be much lower than their critical loads without posing any danger of atmospheric acidic deposition on the soil systems. The study indicated that the system is still protective due to high pH of soil. The nature of buffering capability of calcium derived from soil dust can be considered as a natural tool to combat acidification in the Indian region. The results showed that the pollution status in Delhi is still within the safe limits. However, at the pace at which the city is growing, it is likely that in coming decades, it may exceed these critical values. In order to set deposition limits and avoid adverse effects of acidic deposition this approach can be applied in India too. Such approach is very useful, not only in abating pollution but also in devising means of cost optimal emission abatement strategies.

  8. Synergistic formation of sulfate and ammonium resulting from reaction between SO2 and NH3 on typical mineral dust.

    PubMed

    Yang, Weiwei; He, Hong; Ma, Qingxin; Ma, Jinzhu; Liu, Yongchun; Liu, Pengfei; Mu, Yujing

    2016-01-14

    The heterogeneous reactions of SO2 and NH3 on typical mineral oxides were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). A new sulfate formation pathway was proposed where NH3 accelerated the formation of sulfate species. The results revealed that surface hydroxyls and oxygen played principal roles in the conversion of SO2 to sulfate. It was proposed that NH3 adsorbed onto Lewis acid sites, and hydroxyls and water molecules adsorbed on the surfaces of mineral dust. The enhancement of surface Lewis basicity by NH3 induced more SO2 molecules to adsorb on the surface, which were further oxidized to sulfate by interacting with surface hydroxyls and oxygen atoms. The formation of sulfate, in turn, contributed to the adsorption of NH3, mainly as NH4(+) due to enhanced Brønsted acid sites. The IC results showed that the synergistic effect between SO2 and NH3 was more significant on acidic oxides like γ-Al2O3 and α-Fe2O3 compared to basic oxides like MgO.

  9. Pulmonary epithelial response in the rat lung to instilled Montserrat respirable dusts and their major mineral components

    PubMed Central

    Housley, D; Berube, K; Jones, T; Anderson, S; Pooley, F; Richards, R

    2002-01-01

    Background: The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. Aims: To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz). Methods: Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes. Results: Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage. Conclusion: Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation. PMID:12107295

  10. Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

    PubMed

    Zhang, Yifeng; Shotyk, William; Zaccone, Claudio; Noernberg, Tommy; Pelletier, Rick; Bicalho, Beatriz; Froese, Duane G; Davies, Lauren; Martin, Jonathan W

    2016-02-16

    Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks.

  11. Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

    PubMed

    Zhang, Yifeng; Shotyk, William; Zaccone, Claudio; Noernberg, Tommy; Pelletier, Rick; Bicalho, Beatriz; Froese, Duane G; Davies, Lauren; Martin, Jonathan W

    2016-02-16

    Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks. PMID:26771587

  12. Airborne microorganisms in the African desert dust corridor over the mid-Atlantic ridge, Ocean Drilling Program, Leg 209

    USGS Publications Warehouse

    Griffin, Dale W.; Westphal, Douglas L.; Gray, Michael A.

    2006-01-01

    The objective of this study was to enhance our understanding of the fate and trans-Atlantic transport of dustborne microorganisms from Northern Africa to the Caribbean and Americas, and more specifically to determine if culturable populations could be detected at a mid-ocean site, closer to the source of dust relative to land-based Caribbean sites, during the early summer months of May and June. Between the dates of 22 May and 30 June 2003, daily air samples were collected and evaluated for the presence of culturable bacterial and fungal colony-forming units (CFU). Here we report a statistically significant correlation between daily atmospheric CFU counts at a mid-ocean research site (???15??N, 45??W) and daily desert dust concentrations as determined by the U.S. Navy's Naval Aerosol Analysis and Prediction System (NAAPS) Global Aerosol Model (Honrath et al. (2004). Journal of Geophysical Research, 109; Johnson et al. (2003). Global Biogeochemical Cycles, 17, 1063; Reid et al. (2004). Geophysical Research Letters, 31; Schollaert, Yoder, Westphal, & O'Reilly (2003). Journal of Geophysical Research, 108, 3191). ?? Springer Science+Business Media B.V. 2006.

  13. Kinetics of deposition and clearance of inhaled mineral dusts during chronic exposure.

    PubMed Central

    Vincent, J H; Johnston, A M; Jones, A D; Bolton, R E; Addison, J

    1985-01-01

    New inhalation studies have been carried out with rats exposed to UICC (Union International Contre le Cancer) amosite asbestos, with the main aim of further elucidating the factors the influence the accumulation of dust in the lung during prolonged chronic exposure. The results show that, for exposure times beyond a few weeks, the lung burden rises linearly and does not level off as predicted by simple models based on ideas taken from the 1966 report of the Task Group on Lung Dynamics. Furthermore, the lung burden is found to scale directly in proportion to the exposure concentration in a way that seems to contradict the overload hypothesis stated earlier. Nevertheless, the general pattern exhibited by our results for asbestos is markedly similar to that found elsewhere for rats inhaling diesel fume, leading to the suggestion that it is general (and not specific to fibrous dust); and the hypothesis that, whereas overload of clearance can take place at high lung burdens after exposure has ceased, it is cancelled by the sustained stimulus to clearance mechanisms provided by the continuous challenge of chronic exposure. The linearity of the increase in lung burden is explained in terms of a kinetic model involving sequestration of some inhaled material to parts of the lung where it is difficult to clear. The particular sequestration model favoured is one where, the longer a particle remains in the lung without being cleared, the more likely it will be sequestrated (and therefore less likely cleared). It is believed that such ideas may eventually be useful in forming exposure-dose relations for epidemiology. PMID:2864076

  14. Characterization of dust emission from alluvial sediments using aircraft observations and modeling

    NASA Astrophysics Data System (ADS)

    Schepanski, K.; Flamant, C.; Chaboureau, J.; Kocha, C.; Banks, J.; Brindley, H. E.; Lavaysse, C.; Marnas, F.; Pelon, J.; Tulet, P.

    2013-12-01

    Recent studies using satellite observations show that numerous dust sources are located in the foothills of arid and semi-arid mountain regions such as over North Africa. Alluvial sediments deposited on the valley bottoms and flood plains are very prone to wind erosion and frequently serve as dust source. High surface wind speeds related to the break-down of the nocturnal low-level jet (LLJ) during the morning hours are identified as a frequent driving mechanism for dust uplift. We investigate dust emission from alluvial dust sources located within the upland region in northern Mauritania and discuss the impact of valleys with regard to their role as dust source. Measures for local atmospheric dust burden were retrieved from airborne observations, MSG SEVIR dust AOD fields and MesoNH model simulations, and analyzed in order to provide complementary information on dust source activation and local dust transport at different horizontal scales. Vertical distribution of atmospheric mineral dust was obtained from the LNG backscatter lidar system flying aboard the French Falcon-20 aircraft. Lidar extinction coefficients were compared to topography, aerial photographs, and dust AOD fields to confirm the relevance of alluvial sediments at the valley bottoms as dust source. The observed dust emission event was further evaluated using the regional model MesoNH. A sensitivity study on the impact of the horizontal grid spacing highlights the importance of the spatial resolution on simulated dust loadings. The results further illustrate the importance of an explicit representation of alluvial dust sources in such models to better capture the spatial-temporal distribution of airborne dust concentrations.

  15. Repetitive Immunoassay with a Surface Acoustic Wave Device and a Highly Stable Protein Monolayer for On-Site Monitoring of Airborne Dust Mite Allergens.

    PubMed

    Toma, Koji; Miki, Daisuke; Kishikawa, Chisato; Yoshimura, Naoyuki; Miyajima, Kumiko; Arakawa, Takahiro; Yatsuda, Hiromi; Mitsubayashi, Kohji

    2015-10-20

    This work describes a sensor to be incorporated into the on-site monitoring system of airborne house dust mite (HDM) allergens. A surface acoustic wave (SAW) device was combined with self-assembled monolayers of a highly stable antibody capture protein on the SAW surface that have high resistance to pH change. A sandwich assay was used to measure a HDM allergen, Der f 1 derived from Dermatophagoides farinae. Capture antibodies were cross-linked to a protein G based capture layer (ORLA85) on the sensor surface, thereby only Der f 1 and detection antibodies were regenerated by changing pH, resulting in fast repetition of the measurement. The sensor was characterized through 10 repetitive measurements of Der f 1, which demonstrated high reproducibility of the sensor with the coefficient of variation of 5.6%. The limit of detection (LOD) of the sensor was 6.1 ng·mL(-1), encompassing the standard (20 ng·mL(-1)) set by the World Health Organization. Negligible sensor outputs were observed for five different major allergens including other HDM allergens which tend to have cross-reactivity to Der f 1 and their mixtures with Der f 1. Finally, the sensor lifetime was evaluated by conducting three measurements per day, and the sensor output did not substantially change for 4 days. These characteristics make the SAW immunosensor a promising candidate for incorporation into on-site allergen monitoring systems.

  16. Fingerprints in the Dust

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These MISR nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a spectacularly dusty spring view from April 7, 2001 (middle). The left-hand and middle images are from Terra orbits 2967 and 6928, respectively, and extend from central Manchuria near the top to portions of North and South Korea at the bottom. They are approximately 380 kilometers in width.

    Asia's desert areas are prone to soil erosion, as underground water tables are lowered by prolonged drought and by industrial and agricultural water use. Heavy winds blowing eastward across the arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the April 2001 storm blew across the Pacific Ocean and were carried as far as North America. The minerals transported in this manner are believed to provide nutrients for both oceanic and land ecosystems.

    According to the Xinhua News Agency in China, nearly one million tons of Gobi Desert dust blow into Beijing each year. During a similar dust outbreak last year, the Associated Press reported that the visibility in Beijing had been reduced the point where buildings were barely visible across city streets, and airline schedules were significantly disrupted. The dust has also been implicated in adverse health effects such as respiratory discomfort and eye irritation.

    The image on the right is a higher resolution MISR nadir-camera view of a portion of the April 7, 2001 dust cloud. It covers an area roughly 250 kilometers wide by 470 kilometers high. When viewed at full magnification, a number of atmospheric wave features, like the ridges and valleys of a fingerprint, are apparent. These are probably induced by surface topography, which can disturb the wind flow. A few small cumulus clouds are also visible, and are casting shadows on the thick lower dust layer.

    Analyses of images such as these constitute one phase of MISR

  17. Incidence and progression of pneumoconiosis over nine years in US coal miners: II. Relationship with dust exposure and other potential causative factors

    SciTech Connect

    Attfield, M.; Reger, R.; Glenn, R.

    1984-01-01

    Examination of the incidence and progression of pneumoconiosis over 9 years in 1,261 nationally distributed US coal miners has been undertaken in relationship to potential causative factors. Use has been made of a large body of data on dust levels collected by the Mine Safety and Health Administration principally for compliance purposes. Reported dust levels were low and generally under the current 2 mg/m3 standard. No link between dust level and disease progression could be detected. Some evidence was seen that radiological change was related to dust exposures prior to the study in both coal and noncoal mines, and thus experienced before the current dust standards were mandated. Neither migration of miners nor mining method appeared to be associated with disease incidence or progression. None of these findings can be taken as final, as the period of study is short and the number of cases of pneumoconiosis few. Further study is under way to obtain more reliable information over a longer period of follow-up.

  18. Pneumoconiosis from Agricultural Dust Exposure among Young California Farmworkers

    PubMed Central

    Schenker, Marc B.; Pinkerton, Kent E.; Mitchell, Diane; Vallyathan, Val; Elvine-Kreis, Brenda; Green, Francis H.Y.

    2009-01-01

    Background Agricultural workers are exposed to airborne pollutants, including organic and inorganic (mineral) dusts. Objectives Lung autopsy specimens from consecutive coroner’s cases of Hispanic males in Fresno County, California, (n = 112) were obtained to determine whether mineral dust exposure in agricultural work leads to pneumoconiosis. Methods The left lung was fixed by inflation. We evaluated airway and parenchymal pathology using standardized diagnostic criteria and semiquantitative grading schemata, including the grading of small airways for fibrosis and birefringent mineral dust particles. We analyzed lung dust burden on a subset of 37 lungs following bleach digestion, using scanning electron microscopy (SEM), X-ray spectrometry (XRS) and image analysis, and by X-ray diffraction for crystalline silica (CSi). Farmworkers comprised 51.5% and nonfarmworkers 48.5% of the samples. Results Proximal airways demonstrated little mineral dust accumulation, but membranous and respiratory bronchioles had wall thickening, remodeling, and inflammation associated with carbonaceous and mineral dust deposition. These changes were independently associated with agricultural work, cigarette smoking, and increased age. Mineral dust small airways disease, pneumoconiosis (macules and nodules), and pathologic changes consistent with chronic bronchitis, emphysema, and interstitial fibrosis predominated in farmworkers compared with nonfarmworkers. CSi, determined gravimetrically, and aluminum silicate particles, determined by SEM/XRS, were increased in the lungs of farmworkers compared with nonfarmworkers and were significantly (p < 0.05) associated with small airway disease and pneumoconiosis. Conclusion Mineral dust exposure is associated with increased small airway disease and pneumoconiosis among California farmworkers; however, the clinical significance and natural history of these changes remains to be determined. PMID:19590695

  19. Loss of lung function associated with exposure to silica dust and with smoking and its relation to disability and mortality in South African gold miners.

    PubMed Central

    Hnizdo, E

    1992-01-01

    The data from a lung function study on 2209 white 45-54 year old South African gold miners in 1968-71 and at a five year follow up examination, were analysed to establish the actual loss of lung function associated with exposure to silica dust and with smoking. Ex-smokers were excluded from the analysis. Of the remaining 1625 subjects, 1249 had the five year follow up test of lung function. The estimated excess loss of lung function for a 50 year old gold miner, associated with 24 years of underground dust exposure of an average respirable dust concentration of 0.30 mg m-3 (14.4 ghm-3) was 236 ml of FEV1 (95% confidence interval (95% CI 134-337) and 217 ml of FVC (95% CI 110-324). By comparison, the effect of smoking one packet of cigarettes a day over 30 years was associated with an estimated loss of 552 ml of FEV1 (95% CI 461-644) and 335 ml of FVC (95% CI 170-500). The cumulative dust exposure was not associated with the longitudinal loss of FEV1 or FVC when the initial FEV1 and FVC were adjusted in the models. According to the predicted values, however, gold miners appear to have a greater loss of lung function from 50 to 55 years of age than that predicted for a general population. PMID:1322158

  20. Identifying errors