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Sample records for airborne dust concentrations

  1. High concentration dust monitor

    NASA Astrophysics Data System (ADS)

    Lilienfeld, P.

    1981-06-01

    The development, design, fabrication, and testing of a portable, self-contained prototype monitoring instrument capable of detecting and measuring airborne coal dust levels as concentrations in the range of 20 to 500 g/cu m is described. The output of the high concentration dust monitor is essentially independent of particle size and composition, with a response time of 10 seconds. Direct concentration readout as well as internal memory or recording capabilities are incorporated in the device. The operation of the instrument is based on direct sensing of the mass concentration of airborne dust by air-path beta radiation attenuation. The monitor is battery operated and incorporates a microprocessor that controls periodic automatic zero referencing, executes the mass computations, records the data for subsequent playback, and performs internal diagnostic checks.

  2. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  3. 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.

  4. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.

  5. 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.

  6. Grain fever syndrome induced by inhalation of airborne grain dust.

    PubMed

    doPico, G A; Flaherty, D; Bhansali, P; Chavaje, N

    1982-05-01

    To study the clinical and physiologic manifestations of the grain fever syndrome and the potentially pathogenic role of complement activation, 12 subjects (six grain workers and six healthy non-grain workers) underwent inhalation provocations with airborne grain dust. The clinical response was characterized by facial warmth, headache, malaise, myalgias, feverish sensation, chilliness, throat and tracheal burning sensation, chest tightness, dyspnea, cough, and expectoration. Fever developed in four grain workers and two controls. Leukocytosis, ranging between 11,700 and 24,300 leukocytes/mm3 with left shift, developed in five grain workers and five controls. There was no evidence of complement activation by the classical or alternate pathway. None of the subjects had serum precipitins to grain dust. The pulmonary response was characterized by a decrease in FEV1, FVC, MMF, Vmax50, and Vmax75, with significant rise in pulmonary resistance and consistent change in dynamic compliance but without changes in static compliance or diffusing capacity. Hence, grain dust inhalation induced diffuse airways obstruction without detectable parenchymal reaction. The airways response to high concentrations of grain dust inhalation were unrelated to the presence of immediate skin hypersensitivity. Although we cannot exclude the etiopathogenetic role of an immunologic reaction to grain dust, our data do not support the hypothesis that the grain fever syndrome is a precipitin-mediated allergic pneumonitis. More likely, the manifestations of grain fever probably reflect the host reaction to grain dust bacterial endotoxins and/or nonallergic mediator release by grain or grain dust constituents.

  7. Mechanical intervention for reducing dust concentration in traditional rice mills

    PubMed Central

    PRANAV, Prabhanjan K.; BISWAS, Mrinmoy

    2016-01-01

    A huge number of workers are employed in traditional rice mills where they are potentially exposed to dust. In this study a dust collection system was developed to capture the airborne dust in the rice mill. The feeding and sieving section of the mill was identified as major dust creating zone. The dust was captured by creating suitable air stream at feeding and sieving sections of the mill and collected in cyclone dust collector. The air stream was created by blower which was selected on the basis to get minimum air speed of 0.5 m/s in the working zones of workers. It was observed that the developed system is successfully collects the significant amount of dust and able to reduce the dust concentration up to 58%. Further, the respirable dust concentration reduced to below 5 mg/m3 throughout the mill which is within the recommended limit of dust exposure. PMID:26829976

  8. 30 CFR 33.33 - Allowable limits 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... test samples collected at each drill operator's position, and the difference shall be designated as the... samples. (b) Under each prescribed test condition, the net concentration of airborne dust at each...

  9. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... test samples collected at each drill operator's position, and the difference shall be designated as the... samples. (b) Under each prescribed test condition, the net concentration of airborne dust at each...

  10. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... test samples collected at each drill operator's position, and the difference shall be designated as the... samples. (b) Under each prescribed test condition, the net concentration of airborne dust at each...

  11. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... test samples collected at each drill operator's position, and the difference shall be designated as the... samples. (b) Under each prescribed test condition, the net concentration of airborne dust at each...

  12. 30 CFR 33.33 - Allowable limits of dust concentration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... test samples collected at each drill operator's position, and the difference shall be designated as the... samples. (b) Under each prescribed test condition, the net concentration of airborne dust at each...

  13. 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

  14. 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.

  15. Airborne Sea of Dust over China

    NASA Technical Reports Server (NTRS)

    2002-01-01

    TDust covered northern China in the last week of March during some of the worst dust storms to hit the region in a decade. The dust obscuring China's Inner Mongolian and Shanxi Provinces on March 24, 2002, is compared with a relatively clear day (October 31, 2001) in these images from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera aboard NASA's Terra satellite. Each image represents an area of about 380 by 630 kilometers (236 by 391 miles). In the image from late March, shown on the right, wave patterns in the yellowish cloud liken the storm to an airborne ocean of dust. The veil of particulates obscures features on the surface north of the Yellow River (visible in the lower left). The area shown lies near the edge of the Gobi desert, a few hundred kilometers, or miles, west of Beijing. Dust originates from the desert and travels east across northern China toward the Pacific Ocean. For especially severe storms, fine particles can travel as far as North America. The Multi-angle Imaging SpectroRadiometer, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., is one of five Earth-observing instruments aboard the Terra satellite, launched in December 1999. The instrument acquires images of Earth at nine angles simultaneously, using nine separate cameras pointed forward, downward and backward along its flight path. The change in reflection at different view angles affords the means to distinguish different types of atmospheric particles, cloud forms and land surface covers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team

  16. Partitioning of phthalates among the gas phase, airborne particles and settled dust in indoor environments

    NASA Astrophysics Data System (ADS)

    Weschler, Charles J.; Salthammer, Tunga; Fromme, Hermann

    A critical evaluation of human exposure to phthalate esters in indoor environments requires the determination of their distribution among the gas phase, airborne particles and settled dust. If sorption from the gas phase is the dominant mechanism whereby a given phthalate is associated with both airborne particles and settled dust, there should be a predictable relationship between its particle and dust concentrations. The present paper tests this for six phthalate esters (DMP, DEP, DnBP, DiBP, BBzP and DEHP) that have been measured in both the air and the settled dust of 30 Berlin apartments. The particle concentration, CParticle, of a given phthalate was calculated from its total airborne concentration and the concentration of airborne particles (PM 4). This required knowledge of the particle-gas partition coefficient, Kp, which was estimated from either the saturation vapor pressure ( ps) or the octanol/air partition coefficient ( KOA). For each phthalate in each apartment, the ratio of its particle concentration to its dust concentration ( CParticle/ CDust) was calculated. The median values of this ratio were within an order of magnitude of one another for five of the phthalate esters despite the fact that their vapor pressures span four orders of magnitude. This indicates that measurements of phthalate ester concentrations in settled dust can provide an estimate of their concentration in airborne particles. When the latter information is coupled with measurements of airborne particle concentrations, the gas-phase concentrations of phthalates can also be estimated and, subsequently, the contribution of each of these compartments to indoor phthalate exposures.

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

    PubMed Central

    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. PMID:26618374

  18. 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.

  19. Saharan Mineral Dust Experiment SAMUM 2006: Airborne observations of dust particle properties and vertical dust profiles

    NASA Astrophysics Data System (ADS)

    Petzold, A.; Weinzierl, B.; Esselborn, M.; Fiebig, M.; Fix, A.; Kiemle, C.; Wirth, M.; Müller, D.; Wendisch, M.; Schuetz, L.; Kandler, K.; Kahn, R.; Wagner, F.; Pereira, S.; Virkkula, A.

    2006-12-01

    The Saharan Mineral Dust Experiment (SAMUM) is an initiative of several German institutes. Its goal is the characterisation of optical, physical, chemical, and radiative properties of Saharan dust at the source region. SAMUM data may serve as ground truth data to validate satellite products and atmospheric transport models, and to support the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) mission. The first SAMUM intensive field phase was carried out in May/June 2006 in Southern Morocco. Ground sites were Ouarzazate (30.93° N, 6.9° W), Zagora (30.15° N, 5.37°), and Evora (38.53°N, 7.90°E) in Portugal for long- range transport studies. Research aircraft were operating from Ouarzazate (Partenavia, local flights) and Casablanca (DLR Falcon) at the Moroccan west coast As part of SAMUM, airborne measurements of dust particle properties were conducted using the German research aircraft Falcon. The DLR Falcon was equipped with an extensive set of aerosol physico-chemical instruments for size, volatility, and absorption measurements, impactor sampling for chemical analyses and with a nadir-looking high spectral resolution lidar (HSRL) for measuring aerosol extinction at 532 nm, and aerosol backscatter and depolarisation at 532 nm and 1064 nm. The field sites were equipped with aerosol sampling devices and instruments for particle size distribution measurements. During the SAMUM core phase, three large-scale dust events were probed which extended from southern Morocco to Portugal. Vertical (0 10 km) and horizontal (Saharan border to southern Portugal) dust plume structures, aerosol optical depth as well as particle microphysical and optical properties were studied for all cases. The upper boundary of the dust layers was found at altitudes between 4 and 6 km above sea level. The internal structure of the dust layers varied from well mixed to stratified. The influence of the Atlas Mountains on the lifting of the dust layers was monitored

  20. Exposure assessment to airborne endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide in open style swine houses.

    PubMed

    Chang, C W; Chung, H; Huang, C F; Su, H J

    2001-08-01

    Information is limited for the exposure levels of airborne hazardous substances in swine feed buildings that are not completely enclosed. Open-style breeding, growing and finishing swine houses in six farms in subtropical Taiwan were studied for the airborne concentrations of endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide. The air in the farrowing and nursery stalls as partially enclosed was also simultaneously evaluated. Three selected gases and airborne dusts were quantified respectively by using Drager diffusion tubes and a filter-weighing method. Endotoxin was analyzed by the Limulus amoebocyte lysate assay. Average concentration of airborne total endotoxin among piggeries was between 36.8 and 298 EU/m(3), while that for respirable endotoxin was 14.1-129 EU/m(3). Mean concentration of total dust was between 0.15 and 0.34 mg/m(3), with average level of respirable dust of 0.14 mg/m(3). The respective concentrations of NH3, CO2 and H2S were less than 5 ppm, 600-895 ppm and less than 0.2 ppm. Airborne concentrations of total dust and endotoxin in the nursery house were higher than in the other types of swine houses. The finishing house presented the highest exposure risk to NH3, CO2 and H2S. Employees working in the finishing stalls were also exposed to the highest airborne levels of respirable endotoxin and dust. On the other hand, the air of the breeding units was the least contaminated in terms of airborne endotoxin, dust, NH3, CO2 and H2S. The airborne concentrations of substances measured in the present study were all lower than most of published studies conducted in mainly enclosed swine buildings. Distinct characteristics, including maintaining swine houses in an open status and frequent spraying water inside the stalls, significantly reduce accumulation of gases and airborne particulates.

  1. 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

  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. 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

  4. 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

  5. Temporal variability in airborne pollen concentrations.

    PubMed

    Raynor, G S; Hayes, J V; Ogden, E C

    1976-06-01

    Tests were conducted to determine the relationship between concentrations of airborne pollens and sampling time, using sequential rotoslide samplers at urban and rural locations. Short-period data showed an increase in variability with time between samples. Two-hour data showed a stronger trend for the first 12 hours but better agreement as the time between samples approached one day.

  6. 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

  7. Airborne Dust Modified the North American Climate During the 1930's Dust Bowl

    NASA Astrophysics Data System (ADS)

    O'Brien, T. A.; Solmon, F.; Sloan, L. C.; Snyder, M. A.

    2007-05-01

    In the 1930's Dust Bowl, drought in Mid-Western North America, in conjunction with wide-scale planting of drought-vulnerable crops, resulted in massive dust storms. The presence of dust in the atmosphere may have directly altered the energy budget of North America by the scattering and absorption of radiation and thus may have acted as a feedback to the regional drought conditions. Through a climate modeling sensitivity study of North American climate investigating the impact of airborne dust during the 1930's (using a regional model, RegCM3), we find that areas with moderate to high dust-loading have reduced surface temperatures (~1K) and reduced evapotranspiration (~0.5 mm/day). We also find spatially-coherent, statistically significant changes in precipitation patterns over eastern North America during Spring, Summer, and Fall: areas gain and lose as much as 2 mm/day of precipitation. We are working on a more detailed analysis to determine the causal relationship(s) between airborne dust and precipitation patterns; we hypothesize that the spatially non-uniform change in the energy budget, caused by dust loading, modifies regional dynamics and indirectly modifies precipitation patterns.

  8. 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

  9. Strong capping inversion over the Tokyo metropolitan area associated with airborne Asian dust

    NASA Astrophysics Data System (ADS)

    Tsunematsu, Nobumitsu; Sakai, Tetsu; Nagai, Tomohiro

    2006-10-01

    Lidar measurements in the Tokyo metropolitan area showed that the optical thickness of airborne Asian dust rapidly increased on the morning of April 28, 2005, owing to the arrival of a thick Asian dust layer (ADL), which settled on the planetary boundary layer (PBL). Radiosonde measurements showed that atmospheric temperature in the lower troposphere increased considerably after the arrival of the ADL to the extent that the increment rate reached 12 K/day. Strong capping inversion (CI) was thus formed between the ADL and the PBL with the maximum rate of 0.1 K/m. It was mainly caused by the appearance of a deep isentropic layer that well corresponded to the ADL, indicating that the Asian dust-laden heated and well-mixed air layer led to the temperature increment and consequently induced the CI. The CI inhibited the PBL evolution and caused a higher aerosol concentration in the PBL in the metropolitan area.

  10. Fungal types and concentrations from settled dust in normal residences.

    PubMed

    Hicks, Jeffrey B; Lu, Elizabeth T; De Guzman, Rachel; Weingart, Michal

    2005-10-01

    Analysis of settled dust collected from carpeting and furnishings is occasionally used by investigators to determine whether an environment contains unusual fungi. Little information is available concerning the types and concentrations of culturable fungi present on textile surfaces in normal residential settings not affected by unusual mold reservoirs, such as from fungal growth sites within the built environment. This study presents the results of the collection and analysis of surface dust from 26 residential environments that were prescreened by interview, physical inspection, and air sampling to limit the surface dust collection to structures in which there was no history of water intrusion, flooding, plumbing leaks, signs of mold growth, or evidence of unusual airborne fungal spore types or concentrations. In those structures found to have no history or indications of water events or unusual fungi, surface dust was vacuumed from prescribed horizontal areas on carpet and textile-covered furnishings. These samples were then subjected to fungal culture, from which viable colonies were enumerated and identified. Based on the study results, it does not appear reasonable that the frequently quoted total fungi concentration exceeding 10(5) CFU/g is definitive evidence that a residential surface is contaminated with unusual amounts of culturable fungi. Collocated samples collected from eight side-by-side carpets sections revealed poor reproducibility. While settled dust sampling may be appropriate for determining the fungal status of a localized area, or as a gross screening tool, using settled dust results alone to establish the presence of unusual fungal types or concentrations within a structure appears to be inappropriate, and using settled dust results with other investigative methods, such as visual observations and air sampling, requires cautious interpretation.

  11. Modeled global effects of airborne desert dust on air quality and premature mortality

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    Fine particulate matter is one of the most important factors contributing to air pollution. Epidemiological studies have related increased levels of atmospheric particulate matter to premature human mortality caused by cardiopulmonary disease and lung cancer. However, a limited number of investigations have focused on the contribution of airborne desert dust particles. Here we assess the effects of dust particles with an aerodynamic diameter smaller than 2.5 μm (DU2.5) on human mortality for the year 2005. We used the EMAC atmospheric-chemistry general circulation model at high resolution to simulate global atmospheric dust concentrations. We applied a health impact function to estimate premature mortality for the global population of 30 yr and older, using parameters from epidemiological studies. We estimate a global cardiopulmonary mortality of about 402 000 in 2005. The associated years of life lost are about 3.47 million per year. We estimate the global fraction of the cardiopulmonary deaths caused by atmospheric desert dust to be about 1.8%, though in the 20 countries most affected by dust this is much higher, about 15-50%. These countries are primarily found in the so-called "dust belt" from North Africa across the Middle East and South Asia to East Asia

  12. Modeled global effects of airborne desert dust on air quality and premature mortality

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    Fine particulate matter is one of the most important factors contributing to air pollution. Epidemiological studies have related increased levels of atmospheric particulate matter to premature human mortality caused by cardiopulmonary disease and lung cancer. However, a limited number of investigations have focused on the contribution of airborne desert dust particles. Here we assess the effects of dust particles with an aerodynamic diameter smaller than 2.5 μm (DU2.5) on human mortality for the year 2005. We used the EMAC atmospheric chemistry general circulation model at high resolution to simulate global atmospheric dust concentrations. We applied a health impact function to estimate premature mortality for the global population of 30 yr and older, using parameters from epidemiological studies. We estimate a global cardiopulmonary mortality of about 402 thousand and about 10 thousand by lung cancer in 2005. The associated years of life lost are about 3.47 million and 96 thousand per year due to cardiopulmonary disease and lung cancer, respectively. We estimate the global fraction of the cardiopulmonary and lung cancer deaths caused by atmospheric desert dust to be about 1.7%, though in the 20 countries most affected by dust this is much higher, about 15-50%. These countries are primarily found in the so-called "dust belt" from North Africa across the Middle East and South Asia to East Asia.

  13. 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

  14. 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

  15. Spatial variability in airborne pollen concentrations.

    PubMed

    Raynor, G S; Ogden, E C; Hayes, J V

    1975-03-01

    Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.

  16. Alterations in the airborne bacterial community during Asian dust events occurring between February and March 2015 in South Korea

    PubMed Central

    Cha, Seho; Lee, Dongwook; Jang, Jun Hyeong; Lim, Sora; Yang, Dahye; Seo, Taegun

    2016-01-01

    During Asian dust events, a relatively high concentration of particulate matter is transported by wind from arid and semi-arid regions, such as the Gobi and Taklamakan deserts, to nearby countries, including China, Korea, and Japan. The dust particles contain various microorganisms, which can affect human health as well as the environmental microbe population. In the current study, we investigated the characteristics of the airborne bacterial community during Asian dust events between February and March 2015 in South Korea. Bacterial diversity indexes such as operational taxonomic units, Chao1 and Inverse Simpson index were increased, along with total 16S rRNA gene copy number during Asian dust events. The bacterial community structure during Asian dust events was clearly distinguishable from that during non-Asian dust days. The genera Bacillus and Modestobacter were increased 3.9- and 2.7-fold, respectively, while Escherichia-Shigella was decreased by 89.8%. A non-metric multidimensional scaling plot with metadata analysis revealed association of particulate matter concentration, but not temperature, humidity or wind speed, with bacterial community structure, suggesting that the newly transported dust particles contain various microorganisms that influence the airborne bacterial environment. PMID:27849049

  17. 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

  18. 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

  19. A Methodology to Monitor Airborne PM10 Dust Particles Using a Small Unmanned Aerial Vehicle

    PubMed Central

    Alvarado, Miguel; Gonzalez, Felipe; Erskine, Peter; Cliff, David; Heuff, Darlene

    2017-01-01

    Throughout the process of coal extraction from surface mines, gases and particles are emitted in the form of fugitive emissions by activities such as hauling, blasting and transportation. As these emissions are diffuse in nature, estimations based upon emission factors and dispersion/advection equations need to be measured directly from the atmosphere. This paper expands upon previous research undertaken to develop a relative methodology to monitor PM10 dust particles produced by mining activities making use of small unmanned aerial vehicles (UAVs). A module sensor using a laser particle counter (OPC-N2 from Alphasense, Great Notley, Essex, UK) was tested. An aerodynamic flow experiment was undertaken to determine the position and length of a sampling probe of the sensing module. Flight tests were conducted in order to demonstrate that the sensor provided data which could be used to calculate the emission rate of a source. Emission rates are a critical variable for further predictive dispersion estimates. First, data collected by the airborne module was verified using a 5.0 m tower in which a TSI DRX 8533 (reference dust monitoring device, TSI, Shoreview, MN, USA) and a duplicate of the module sensor were installed. Second, concentration values collected by the monitoring module attached to the UAV (airborne module) obtaining a percentage error of 1.1%. Finally, emission rates from the source were calculated, with airborne data, obtaining errors as low as 1.2%. These errors are low and indicate that the readings collected with the airborne module are comparable to the TSI DRX and could be used to obtain specific emission factors from fugitive emissions for industrial activities. PMID:28216557

  20. A Methodology to Monitor Airborne PM10 Dust Particles Using a Small Unmanned Aerial Vehicle.

    PubMed

    Alvarado, Miguel; Gonzalez, Felipe; Erskine, Peter; Cliff, David; Heuff, Darlene

    2017-02-14

    Throughout the process of coal extraction from surface mines, gases and particles are emitted in the form of fugitive emissions by activities such as hauling, blasting and transportation. As these emissions are diffuse in nature, estimations based upon emission factors and dispersion/advection equations need to be measured directly from the atmosphere. This paper expands upon previous research undertaken to develop a relative methodology to monitor PM10 dust particles produced by mining activities making use of small unmanned aerial vehicles (UAVs). A module sensor using a laser particle counter (OPC-N2 from Alphasense, Great Notley, Essex, UK) was tested. An aerodynamic flow experiment was undertaken to determine the position and length of a sampling probe of the sensing module. Flight tests were conducted in order to demonstrate that the sensor provided data which could be used to calculate the emission rate of a source. Emission rates are a critical variable for further predictive dispersion estimates. First, data collected by the airborne module was verified using a 5.0 m tower in which a TSI DRX 8533 (reference dust monitoring device, TSI, Shoreview, MN, USA) and a duplicate of the module sensor were installed. Second, concentration values collected by the monitoring module attached to the UAV (airborne module) obtaining a percentage error of 1.1%. Finally, emission rates from the source were calculated, with airborne data, obtaining errors as low as 1.2%. These errors are low and indicate that the readings collected with the airborne module are comparable to the TSI DRX and could be used to obtain specific emission factors from fugitive emissions for industrial activities.

  1. Endotoxin exposure assessment in wood-processing industry: airborne versus settled dust levels.

    PubMed

    Pipinić, Ivana Sabolić; Varnai, Veda Marija; Lucić, Ruzica Beljo; Cavlović, Ankica; Prester, Ljerka; Orct, Tatjana; Macan, Jelena

    2010-06-01

    Wood processing is usually performed in environments with large amounts of endotoxin-rich bioaerosols that are associated with a variety of health effects. The aim of this preliminary study was to assess the relation between endotoxin levels in settled and airborne dust in wood-processing industry. Ten pairs of airborne and settled dust samples were collected in a sawmill and parquet manufacture of two wood-processing plants in Croatia. Endotoxin was assayed with a chromogenic end-point LAL (Limulus amebocyte lysate) method. The results showed that endotoxin levels in airborne respirable dust were above the proposed occupational exposure limit of 125 EU m(-3) and could be considered hazardous for the respiratory system. In settled dust they ranged between 229.7 EU mg(-1) and 604.3 EU mg(-1) and in airborne dust between 166.8 EU mg(-1) and 671.6 EU m(-3), but there was no significant correlation between them (Spearman's rho=0.358, P=0.310). This study points to sawmill settled dust as endotoxin reservoir and suggests that it may add to already high exposure to airborne endotoxins associated with wood processing. Investigations of the relation between settled and airborne endotoxin levels should be continued to better understand the sources and sites of endotoxin contamination in wood-processing industry.

  2. Variations in the structure of airborne bacterial communities in Tsogt-Ovoo of Gobi desert area during dust events.

    PubMed

    Maki, Teruya; Kurosaki, Yasunori; Onishi, Kazunari; Lee, Kevin C; Pointing, Stephen B; Jugder, Dulam; Yamanaka, Norikazu; Hasegawa, Hiroshi; Shinoda, Masato

    2017-01-01

    Asian dust events transport the airborne bacteria in Chinese desert regions as well as mineral particles and influence downwind area varying biological ecosystems and climate changes. However, the airborne bacterial dynamics were rarely investigated in the Gobi desert area, where dust events are highly frequent. In this study, air samplings were sequentially performed at a 2-m high above the ground at the sampling site located in desert area (Tsogt-Ovoo of Gobi desert; Mongolia 44.2304°N, 105.1700°E). During the dust event days, the bacterial cells and mineral particles increased to more than tenfold of concentrations. MiSeq sequencing targeting 16S ribosomal DNA revealed that the airborne bacteria in desert area mainly belonged to the classes Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Bacilli, Alpha-proteobacteria, Beta-proteobacteria, and Gamma-proteobacteria. The bacterial community structures were different between dust events and non-dust events. The air samples collected at the dust events indicated high abundance rates of Alpha-proteobacteria, which were reported to dominate on the leaf surfaces of plants or in the saline lake environments. After the dust events, the members of Firmicutes (Bacilli) and Bacteroidetes, which are known to form endospore and attach with coarse particles, respectively, increased their relative abundances in the air samples. Presumably, the bacterial compositions and diversities in atmosphere significantly vary during dust events, which carry some particles from grassland (phyllo-sphere), dry lake, and sand surfaces, as well as some bacterial populations such as Firmicutes and Bacteroidetes maintain in the atmosphere for longer time.

  3. 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

  4. Spacecraft Maximum Allowable Concentrations for Airborne Contaminants

    NASA Technical Reports Server (NTRS)

    James, John T.

    2008-01-01

    The enclosed table lists official spacecraft maximum allowable concentrations (SMACs), which are guideline values set by the NASA/JSC Toxicology Group in cooperation with the National Research Council Committee on Toxicology (NRCCOT). These values should not be used for situations other than human space flight without careful consideration of the criteria used to set each value. The SMACs take into account a number of unique factors such as the effect of space-flight stress on human physiology, the uniform good health of the astronauts, and the absence of pregnant or very young individuals. Documentation of the values is given in a 5 volume series of books entitled "Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants" published by the National Academy Press, Washington, D.C. These books can be viewed electronically at http://books.nap.edu/openbook.php?record_id=9786&page=3. Short-term (1 and 24 hour) SMACs are set to manage accidental releases aboard a spacecraft and permit risk of minor, reversible effects such as mild mucosal irritation. In contrast, the long-term SMACs are set to fully protect healthy crewmembers from adverse effects resulting from continuous exposure to specific air pollutants for up to 1000 days. Crewmembers with allergies or unusual sensitivity to trace pollutants may not be afforded complete protection, even when long-term SMACs are not exceeded. Crewmember exposures involve a mixture of contaminants, each at a specific concentration (C(sub n)). These contaminants could interact to elicit symptoms of toxicity even though individual contaminants do not exceed their respective SMACs. The air quality is considered acceptable when the toxicity index (T(sub grp)) for each toxicological group of compounds is less than 1, where T(sub grp), is calculated as follows: T(sub grp) = C(sub 1)/SMAC(sub 1) + C(sub 2/SMAC(sub 2) + ...+C(sub n)/SMAC(sub n).

  5. Latex allergens in tire dust and airborne particles.

    PubMed Central

    Miguel, A G; Cass, G R; Weiss, J; Glovsky, M M

    1996-01-01

    The prevalence and severity of latex allergy has increased dramatically in the last 15 years due to exposure to natural rubber products. Although historically this health risk has been elevated in hospital personnel and patients, a recent survey has indicated a significant potential risk for the general population. To obtain a wide-spread source for latex exposure, we have considered tire debris. We have searched for the presence of latex allergens in passenger car and truck tire tread, in debris deposited from the atmosphere near a freeway, and in airborne particulate matter samples representative of the entire year 1993 at two sites in the Los Angeles basin (California). After extraction of the samples with phosphate buffered saline, a modified-ELISA inhibition assay was used to measure relative allergen potency and Western blot analyses were used to identify latex allergens. The inhibition studies with the human IgE latex assay revealed inhibition by the tire tread source samples and ambient freeway dust, as well as by control latex sap and latex glove extracts. Levels of extractable latex allergen per unit of protein extracted were about two orders of magnitude lower for tire tread as compared to latex gloves. Western blot analyses using binding of human IgE from latex-sensitive patients showed a band at 34-36 kDa in all tire and ambient samples. Long Beach and Los Angeles, California, air samples showed four additional bands between 50 and 135 kDa. Alternative Western blot analyses using rabbit IgG raised against latex proteins showed a broad band at 30-50 kDa in all samples, with additional bands in the urban air samples similar to the IgE results. A latex cross-reactive material was identified in mountain cedar. In conclusion, the latex allergens or latex cross-reactive material present in sedimented and airborne particulate material, derived from tire debris, and generated by heavy urban vehicle traffic could be important factors in producing latex allergy

  6. Airborne Dust Monitoring Activities at the National Environmental Satellite, Data and Information Service

    NASA Astrophysics Data System (ADS)

    Stephens, G.; McNamara, D.; Taylor, J.

    2002-12-01

    Wind blown dust can be a hazard to transportation, industrial, and military operations, and much work has been devoted to its analysis and prediction from a meteorological viewpoint. The detection and forecasting of dust outbreaks in near real time is difficult, particularly in remote desert areas with sparse observation networks. The Regional Haze Regulation, passed by Congress in 1999, mandates a reduction in man made inputs to haze in 156 Class I areas (national parks and wilderness areas). Studies have demonstrated that satellite data can be useful in detection and tracking of dust storms. Environmental satellites offer frequent coverage of large geographic areas. The National Environmental Satellite, Data, and Information Service (NESDIS) of the U.S. National Oceanic and Atmospheric Administration (NOAA) operates a system of polar orbiting and geostationary environmental satellites, which sense data in two visible and three infrared channels. Promising results in the detection of airborne dust have been obtained using multispectral techniques to combine information from two or more channels to detect subtle spectral differences. One technique, using a ratio of two thermal channels, detects the presence of airborne dust, and discriminates it from both underlying ground and meteorological clouds. In addition, NESDIS accesses and is investigating for operational use data from several other satellites. The Total Ozone Mapping Spectrometer on board NASA's Earth Probe mission provides an aerosol index product which can detect dust and smoke, and the Moderate Resolution Imaging Spectroradiometer on NASA's Terra and Aqua satellites provide several channels which can detect aerosols in multispectral channel combinations. NESDIS, in cooperation with NOAA's Air Resources Laboratory, produces a daily smoke transport forecast, combining satellite derived smoke source points with a mathematical transport prediction model; such a scheme could be applied to other aerosol

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

    NASA Astrophysics Data System (ADS)

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

    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 (<1.0%) of the actual microbial population in any given environment, dust-borne microorganisms and other associated constituents (organic detritus, toxins, etc.) may play a significant role in the regional human and ecosystem health.

  8. 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.

  9. 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 (

  10. 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.

  11. Assessment of chemical and mineralogical characteristics of airborne dust in the Sistan region, Iran.

    PubMed

    Rashki, A; Eriksson, P G; Rautenbach, C J de W; Kaskaoutis, D G; Grote, W; Dykstra, J

    2013-01-01

    Windblown transport and deposition of dust is widely recognized as an important physical and chemical concern to climate, human health and ecosystems. Sistan is a region located in southeast Iran with extensive wind erosion, severe desertification and intense dust storms, which cause adverse effects in regional air quality and human health. To mitigate the impact of these phenomena, it is vital to ascertain the physical and chemical characteristics of airborne and soil dust. This paper examines for the first time, the mineralogical and chemical properties of dust over Sistan by collecting aerosol samples at two stations established close to a dry-bed lake dust source region, from August 2009 to August 2010. Furthermore, soil samples were collected from topsoil (0-5 cm depth) at several locations in the dry-bed Hamoun lakes and downwind areas. These data were analyzed to investigate the chemical and mineralogical characteristics of dust, relevance of inferred sources and contributions to air pollution. X-ray Diffraction (XRD) analysis of airborne and soil dust samples shows that the dust mineralogy is dominated mainly by quartz (30-40%), calcite (18-23%), muscovite (10-17%), plagioclase (9-12%), chlorite (~6%) and enstatite (~3%), with minor components of dolomite, microcline, halite and gypsum. X-ray Fluorescence (XRF) analyses of all the samples indicate that the most important oxide compositions of the airborne and soil dust are SiO(2), CaO, Al(2)O(3), Na(2)O, MgO and Fe(2)O(3), exhibiting similar percentages for both stations and soil samples. Estimates of Enrichment Factors (EFs) for all studied elements show that all of them have very low EF values, suggesting natural origin from local materials. The results suggest that a common dust source region can be inferred, which is the eroded sedimentary environment in the extensive Hamoun dry lakes lying to the north of Sistan.

  12. 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

  13. Metal and Metalloid Contaminants in Airborne Dust Associated with Mining Operations

    NASA Astrophysics Data System (ADS)

    Betterton, E. A.; Csavina, J. L.; Field, J. P.; Landázuri, A. C.; Felix Villar, O.; Rine, K. P.; Sáez, A.; Pence, J.; Shayan, H.; Russell, M.

    2011-12-01

    Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. In this work, we report the size-resolved chemical characterization of atmospheric aerosols sampled near an inactive Superfund site and at an active mining and smelting site in Arizona. Aerosols were characterized with 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactors (MOUDI), Dustrack monitors, and total suspended particulate (TSP) collectors. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm aerodynamic diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources.

  14. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

    PubMed Central

    Goossens, Dirk

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

  15. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA.

    PubMed

    Goossens, Dirk; Buck, Brenda J; Teng, Yuanxin; McLaurin, Brett T

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g(-1) in topsoil and bedrock, and more than 0.03 μg m(-3) in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m(-3). The results of this study are important because the NDRA is visited by more than 300,000 people annually.

  16. Soluble ferrous iron (Fe (II)) enrichment in airborne dust

    NASA Astrophysics Data System (ADS)

    Bhattachan, Abinash; Reche, Isabel; D'Odorico, Paolo

    2016-09-01

    The input of soluble iron in dust delivered to the ocean and lakes is critical to their biogeochemistry and phytoplankton productivity. Most iron in soils and sediment deposits is insoluble, while only a tiny fraction is soluble and therefore suitable to meet the phytoplankton's requirements for photosynthesis and nitrogen assimilation. Aerosol deposition constitutes a major source of soluble iron to oceans and lakes, and in some regions the low phytoplankton productivity has been related to limitations in the supply of soluble iron from terrestrial sources. It is suggested that during atmospheric transport part of the insoluble iron is converted into soluble form. While the understanding of increased bioavailability of iron during atmospheric transport is improving, there are only a limited number of studies that actually quantify the increase in iron bioavailability in dust. In this study we compare the soluble ferrous iron, Fe (II) content in dust collected at deposition sites in the high-altitude mountains of the Sierra Nevada, Spain, to the source of dust in North Africa. We found that the dust is greatly enriched (on average 15 times) in Fe (II) relative to the fine fraction (<45 µm) of the parent soil collected from North African dust sources.

  17. 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.

  18. Mismatch in aeroallergens and airborne grass pollen concentrations

    NASA Astrophysics Data System (ADS)

    Plaza, M. P.; Alcázar, P.; Hernández-Ceballos, M. A.; Galán, C.

    2016-11-01

    An accurate estimation of the allergen concentration in the atmosphere is essential for allergy sufferers. The major cause of pollinosis all over Europe is due to grass pollen and Phl p 5 has the highest rates of sensitization (>50%) in patients with grass pollen-induced allergy. However, recent research has shown that airborne pollen does not always offer a clear indicator of exposure to aeroallergens. This study aims to evaluate relations between airborne grass pollen and Phl p 5 concentrations in Córdoba (southern Spain) and to study how meteorological parameters influence these atmospheric records. Monitoring was carried out from 2012 to 2014. Hirst-type volumetric spore trap was used for pollen collection, following the protocol recommended by the Spanish Aerobiology Network (REA). Aeroallergen sampling was performed using a low-volume cyclone sampler, and allergenic particles were quantified by ELISA assay. Besides, the influence of main meteorological factors on local airborne pollen and allergen concentrations was surveyed. A significant correlation was observed between grass pollen and Phl p 5 allergen concentrations during the pollen season, but with some sporadic discrepancy episodes. The cumulative annual Pollen Index also varied considerably. A significant correlation has been obtained between airborne pollen and minimum temperature, relative humidity and precipitation, during the three studied years. However, there is no clear relationship between allergens and weather variables. Our findings suggest that the correlation between grass pollen and aeroallergen Phl p 5 concentrations varies from year-to-year probably related to a complex interplay of meteorological variables.

  19. Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash

    SciTech Connect

    Hicks, J.; Yager, J.

    2006-08-15

    This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m{sup 3} to 96 mg/m{sup 3} (mean of 1.8 mg/m{sup 3}). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m{sup 3} (mean value of 0.048 mg/m{sup 3}). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 {mu}m and 8 {mu}m. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected.

  20. Manganese concentrations in soil and settled dust in an area with historic ferroalloy production

    PubMed Central

    Pavilonis, Brian T.; Lioy, Paul J.; Guazzetti, Stefano; Bostick, Benjamin C.; Donna, Filippo; Peli, Marco; Zimmerman, Neil J.; Bertrand, Patrick; Lucas, Erika; Smith, Donald R.; Georgopoulos, Panos G.; Mi, Zhongyuan; Royce, Steven G.; Lucchini, Roberto G.

    2015-01-01

    Ferroalloy production can release a number of metals into the environment, of which manganese (Mn) is of major concern. Other elements include lead, iron, zinc, copper, chromium, and cadmium. Manganese exposure derived from settled dust and suspended aerosols can cause a variety of adverse neurological effects to chronically exposed individuals. To better estimate the current levels of exposure, this study quantified metal levels in dust collected inside homes (n=85), outside homes (n=81), in attics (n=6), and in surface soil (n=252) in an area with historic ferroalloy production. Metals contained in indoor and outdoor dust samples were quantified using inductively coupled plasma optical emission spectroscopy while attic and soil measurements were made with a XRF instrument. Mean Mn concentrations in soil (4600 μg/g) and indoor dust (870 μg/g) collected within 0.5 km of a plant exceeded levels previously found in suburban and urban areas, but did decrease outside 1.0 km to the upper end of background concentrations. Mn concentrations in attic dust were approximately 120 times larger than other indoor dust levels, consistent with historical emissions that yielded high airborne concentrations in the region. Considering the potential health effects that are associated with chronic manganese inhalation and ingestion exposure, remediation of soil near the plants and frequent, on-going hygiene indoors may decrease residential exposure and the likelihood of adverse health effects. PMID:25335867

  1. 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.

  2. Ambrosia airborne pollen concentration modelling and evaluation over Europe

    NASA Astrophysics Data System (ADS)

    Hamaoui-Laguel, Lynda; Vautard, Robert; Viovy, Nicolas; Khvorostyanov, Dmitry; Colette, Augustin

    2014-05-01

    Native from North America, Ambrosia artemisiifolia L. (Common Ragweed) is an invasive annual weed introduced in Europe in the mid-nineteenth century. It has a very high spreading potential throughout Europe and releases very allergenic pollen leading to health problems for sensitive persons. Because of its health effects, it is necessary to develop modelling tools to be able to forecast ambrosia air pollen concentration and to inform allergy populations of allergenic threshold exceedance. This study is realised within the framework of the ATOPICA project (https://www.atopica.eu/) which is designed to provide first steps in tools and estimations of the fate of allergies in Europe due to changes in climate, land use and air quality. To calculate and predict airborne concentrations of ambrosia pollen, a chain of models has been built. Models have been developed or adapted for simulating the phenology (PMP phonological modelling platform), inter-annual production (ORCHIDEE vegetation model), release and airborne processes (CHIMERE chemical transport model) of ragweed pollen. Airborne pollens follow processes similar to air quality pollutants in CHIMERE with some adaptations. The detailed methodology, formulations and input data will be presented. A set of simulations has been performed to simulate airborne concentrations of pollens over long time periods on a large European domain. Hindcast simulations (2000 - 2012) driven by ERA-Interim re-analyses are designed to best simulate past periods airborne pollens. The modelled pollen concentrations are calibrated with observations and validated against additional observations. Then, 20-year long historical simulations (1986 - 2005) are carried out using calibrated ambrosia density distribution and climate model-driven weather in order to serve as a control simulation for future scenarios. By comparison with multi-annual observed daily pollen counts we have shown that the model captures well the gross features of the pollen

  3. Airborne Nicotine Concentrations in the Workplaces of Tobacco Farmers

    PubMed Central

    Yoo, Seok-Ju; Park, Sung-Jun; Kim, Byoung-Seok; Lim, Hyun-Sul; Kim, Jik-Su; Kim, In-Shik

    2014-01-01

    Objectives Nicotine is a natural alkaloid and insecticide in tobacco leaves. Green tobacco sickness (GTS) is known as a disease of acute nicotine intoxication among tobacco farmers. Until now, GTS has been recognized globally as a disease that results from nicotine absorption through the skin. However, we assumed that GTS might also result from nicotine inhalation as well as absorption. We aimed to measure the airborne nicotine concentrations in various work environments of Korean tobacco farmers. Methods We measured the nicotine concentrations in the tobacco fields, private curing barns, and joint curing barns of farmers from July to October 2010. All sampling and analyses of airborne nicotine were conducted according to the National Institute for Occupational Safety and Health manual of analytic methods. Results The airborne nicotine concentrations (geometric mean [geometric standard deviation]) in the tobacco field were 83.4 mg/m3 (1.2) in the upper region and 93.3 mg/m3 (1.2) in the lower region. In addition, the nicotine concentration by personal sampling was 150.1 mg/m3. Similarly, the nicotine concentrations in the private curing barn, workers in curing barns, the front yard of the curing barn, and in the joint curing barn were 323.7 mg/m3 (2.0), 121.0 mg/m3 (1.5), 73.7 mg/m3 (1.7), and 610.3 mg/m3 (1.0), respectively. Conclusions The nicotine concentration in the workplaces of tobacco farmers was very high. Future studies should measure the environmental concentration of nicotine that is inhaled by tobacco farmers. PMID:24921017

  4. Airborne dust and soil particles at the Phoenix landing site, Mars

    NASA Astrophysics Data System (ADS)

    Madsen, M. B.; Drube, L.; Goetz, W.; Leer, K.; Falkenberg, T. V.; Gunnlaugsson, H. P.; Haspang, M. P.; Hviid, S. F.; Ellehøj, M. D.; Lemmon, M. T.

    2009-04-01

    The three iSweep targets on the Phoenix lander instrument deck utilize permanent magnets and 6 different background colors for studies of airborne dust [1]. The name iSweep is short for Improved Sweep Magnet experiments and derives from MER heritage [2, 3] as the rovers carried a sweep magnet, which is a very strong ring magnet built into an aluminum structure. Airborne dust is attracted and held by the magnet and the pattern formed depends on magnetic properties of the dust. The visible/near-infrared spectra acquired of the iSweep are rather similar to typical Martian dust and soil spectra. Because of the multiple background colors of the iSweeps the effect of the translucence of thin dust layers can be studied. This is used to estimate the rate of dust accumulation and will be used to evaluate light scattering properties of the particles. Some particles raised by the retro-rockets during the final descent came to rest on the lander deck and spectra of these particles are studied and compared with those of airborne dust and with spectra obtained from other missions. High resolution images acquired by the Optical Microscope (OM) [4] showed subtle differences between different Phoenix soil samples in terms of particle size and color. Most samples contain orange dust (particles smaller than 10 micrometer) as their major component and silt-sized (50-80 micrometer large) subrounded particles. Both particle types are substantially magnetic. Based on results from the Mars Exploration Rovers, the magnetization of the silt-sized particles is believed to be caused by magnetite. Morphology, texture and color of these particles (ranging from colorless, red-brown to almost black) suggest a multiple origin: The darkest particles probably represent lithic fragments, while the brighter ones could be impact or volcanic glasses. [1] Leer K. et al. (2008) JGR, 113, E00A16. [2] Madsen M.B. et al. (2003) JGR, 108, 8069. [3] Madsen M.B. et al. (2008) JGR (in print). [4] Hecht M.H. et

  5. 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.

  6. 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.

  7. Investigation of coal properties and airborne respirable dust generation. Report of investigations/1998

    SciTech Connect

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

    1998-10-01

    Laboratory crushing experiments were conducted on a range of low- to high-volatile bituminous coals to investigate the various factors influencing airborne respirable dust (ARD) generation. This research was conducted to identify the principles of ARD liberation from the coal product. Five U.S. bituminous coals were uniformly prepared and processed through a double roll crusher located in a low-velocity wind tunnel. Experimental factors studied included inherent coal seam constituents, coal grindability, specific energy of crushing, product size characteristics, dust cloud electrostatic field, and specific ARD generated. The results of this investigation indicate that a combination of several factors are associated with ARD generation. One factor is the effect of coal rank, described by the inherent moist fuel ratio, on the product size characteristics, defined by Schuhmann size function parameters. Another key factor is the effect of air dry loss (ADL) moisture in the coal seam on the breakage-induced electrostatic field of airborne dust. The effect of these factors is that different percentages of <10-micrometers coal particles are dispersed as ARD. A discussion of electrostatic field principles, coal ADL, and its effect on ARD generation is presented.

  8. Vanadium concentrations in settled outdoor dust particles.

    PubMed

    Dundar, Mustafa S

    2006-12-01

    Atmospheric dustfall is an important aspect of urban dust studies. Vanadium is considered as the marker element of air pollution emitted from residual oil and coal combustion. In this study, vanadium levels of outdoor dust particles are determined. The studied area covers the six sites located in Adapazarí (Turkey), which represents an earthquake-hit environment. The mass deposition rate was calculated for each sampling plate over the 30-days collection periods. The deposition rates for the six places in Adapazarí ranged from 20.5 to 84.9 microg/cm2/day. The arithmetic mean deposition rate for all places was 45.3 microg/cm2/day. Total dust deposition and vanadium loadings typically increased in magnitude according to the area order: Kampus > Serdivan > Cark C. > Ozanlar > Erenler > Yeşiltepe and Kampus > Serdivan > Cark C. > Ozanlar > Erenler > Yeşiltepe, respectively. The results suggested that vanadium may be useful for assessing the level of environmental pollution.

  9. 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.

  10. Does cutting of mugwort stands affect airborne pollen concentrations?

    PubMed

    Rantio-Lehtimäki, A; Helander, M L; Karhu, K

    1992-08-01

    Pollen of mugwort (Artemisia vulgaris L.) is the most important allergenic pollen in urban areas of south and central Finland in late summer. The purpose of this study was to investigate, experimentally, whether the cutting of mugwort stands affects its airborne pollen concentrations. Experimental plots were either cut (4 plots) or uncut (4 plots) in 2 previous seasons: 4 of them were small (less than 0.5 hectare) and 4 large (greater than 5 hectares). Finally, the plots were divided randomly into 2 groups according to a third variable, cutting in the study season, 1989. Samples were taken on 2 rainless mornings at the peak mugwort flowering time. Two rotorod type samplers were used at heights of 1 and 2 m from ground level, simulating the inhalation heights of children and adults, respectively. The results indicate that cutting mugwort stands significantly reduces airborne pollen concentrations, but the treated areas have to be large, since in the town area there are plenty of mugwort pollen sources. The pollen concentrations at the 2 heights tested did not differ significantly.

  11. 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.

    2015-04-01

    This study provides an assessment of the chemical composition and global aerosol load of the major inorganic aerosol components and determines the effect of mineral dust on their formation, focusing on aerosol nitrate. To account for this effect, the mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are added to the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers the interactions of K+-Ca2+-Mg2+-NH4+-Na+-SO42--NO3--Cl--H2O aerosol components. Emissions of mineral dust aerosol components (K+-Ca2+-Mg2+-Na+) are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. The presence of the metallic ions on the simulated suite of components can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The updated model improved the nitrate predictions over remote areas and found that the fine aerosol nitrate concentration is highest 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 contribution of mineral dust components to nitrate formation is large in areas with high dust concentrations with impacts that can extend across southern Europe, western USA and northeastern China. The tropospheric burden of aerosol nitrate increases by 44% by considering the interactions of nitrate with mineral dust cations. 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. Sensitivity tests show that nitrate aerosol formation 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

  12. 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.

  13. Diacetyl emissions and airborne dust from butter flavorings used in microwave popcorn production.

    PubMed

    Boylstein, Randy; Piacitelli, Chris; Grote, Ardith; Kanwal, Richard; Kullman, Greg; Kreiss, Kathleen

    2006-10-01

    In microwave popcorn workers, exposure to butter flavorings has been associated with fixed obstructive lung disease resembling bronchiolitis obliterans. Inhalation toxicology studies have shown severe respiratory effects in rats exposed to vapors from a paste butter flavoring, and to diacetyl, a diketone found in most butter flavorings. To gain a better understanding of worker exposures, we assessed diacetyl emissions and airborne dust levels from butter flavorings used by several microwave popcorn manufacturing companies. We heated bulk samples of 40 different butter flavorings (liquids, pastes, and powders) to approximately 50 degrees C and used gas chromatography, with a mass selective detector, to measure the relative abundance of volatile organic compounds emitted. Air sampling was conducted for diacetyl and for total and respirable dust during the mixing of powder, liquid, or paste flavorings with heated soybean oil at a microwave popcorn plant. To further examine the potential for respiratory exposures to powders, we measured dust generated during different simulated methods of manual handling of several powder butter flavorings. Powder flavorings were found to give off much lower diacetyl emissions than pastes or liquids. The mean diacetyl emissions from liquids and pastes were 64 and 26 times larger, respectively, than the mean of diacetyl emissions from powders. The median diacetyl emissions from liquids and pastes were 364 and 72 times larger, respectively, than the median of diacetyl emissions from powders. Fourteen of 16 powders had diacetyl emissions that were lower than the diacetyl emissions from any liquid flavoring and from most paste flavorings. However, simulated handling of powder flavorings showed that a substantial amount of the airborne dust generated was of respirable size and could thus pose its own respiratory hazard. Companies that use butter flavorings should consider substituting flavorings with lower diacetyl emissions and the use of

  14. Determining controls on element concentrations in cement kiln dust leachate

    SciTech Connect

    Duchesne, J.; Reardon, E.J.

    1998-12-31

    Cement kiln dust is a waste residue composed chiefly of oxidized, anhydrous, micron-sized particles generated as a by-product of the manufacture of Portland cement. When cement kiln dust is brought into contact with water, high concentrations of potassium, sulfate and caustic alkalinity are leached. Other constitutents are leached to a lesser extent. The objective of this study was to determine whether the concentration of a given chemical constituent in kiln dust leachate is controlled by the precipitation of a secondary mineral phase or whether its concentration depends on its initial availability to the leachate solution and its subsequent diffusive flux from hydrating particles with time. Differentiating between these two distinctive styles of leaching behavior is necessary to predict the chemical composition of kiln dust leachate under dynamic flow conditions in disposal environments. Evidence of solubility control was found for Si, Ca, Mg, Al, Zn, Ti, Sr, and Ba. The concentrations of Na, Cl, K, Mo, Cr and Se, however, were found to have no solubility control. Because of the observed lack of solubility control and the particularly high concentrations of Cr and Mo in kiln dust leachate, The authors tested two additives to reduce their concentrations: (1) aluminum oxide to promote the precipitation of calcium aluminosulfates and the proxying of chromate and molybdate for sulfate in their structures; and (2) iron metal to promote the reduction of chromate and molybdate to lower valent and less soluble forms. Neither treatment had any effect on the concentration levels of Cr and Mo in solution.

  15. 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.

  16. 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.

  17. 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.

  18. Relationship of airborne trimellitic anhydride concentrations to trimellitic anhydride--induced symptoms and immune responses

    SciTech Connect

    Bernstein, D.I.; Roach, D.E.; McGrath, K.G.; Larsen, R.S.; Zeiss, C.R.; Patterson, R.

    1983-12-01

    Eighteen workers exposed to trimellitic anhydride (TMA) powder were evaluated in 1979. Twelve of these workers were available for longitudinal study until 1982. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to /sup 125/I-TM-HSA were performed. In 1979, five workers had antibody against TM-HSA. Of these, three workers were diagnosed with the late respiratory systemic syndrome (LRSS) and one worker with TMA-induced allergic rhinitis. The LRSS workers had significantly elevated total antibody binding of /sup 125/I-TM-HSA and the worker with rhinitis had significantly elevated specific IgE binding of /sup 125/I-TM-HSA per milliliter of serum. Although TMA handling was intermittent throughout the year, average airborne dust concentrations from 1974 to 1978 at job stations of the two heaviest TMA-exposed occupations, operator and assistant operator, were 2.1 and 0.82 mg/m3, respectively. After local exhaust ventilation had been improved, average airborne dust concentrations of TMA at the two latter job stations fell to levels of 0.03 and 0.01 mg/m3, respectively, in 1982. The decrease in TMA exposure coincided with a gradual fall in total antibody binding of /sup 125/I-TM-HSA per milliliter in 1982 and symptomatic improvement in the three individuals with the LRSS. The continuous low-level exposure of the worker with TMA rhinitis was sufficient to elicit a rise in specific IgE against TM-HSA from 1.1 ng of 125I-TM-HSA bound per milliliter in 1979 to 2.12 in 1982.

  19. 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

  20. Reconstruction of global atmospheric dust concentrations using dust flux measurements in paleoclimatic archives and dust model variables

    NASA Astrophysics Data System (ADS)

    Lambert, F.; Rojas, M.; Gallardo, L.; Mahowald, N. M.; Takemura, T.; KUG, J.; Winckler, G.; Park, R.; Abe-Ouchi, A.

    2013-12-01

    Aerosols are the second most potent agent affecting anthropogenic radiative forcing after greenhouse gases. However, despite some progress in the field, the uncertainty of aerosol impact on present and past climate remains much larger than for other species. The total atmospheric dust load is an important factor for the radiative budget of the atmosphere, and for the micronutrient supply to terrestrial and marine ecosystems. We have collected published dust flux (mass accumulation rate) measurements from marine sediment cores, ice cores, loess fields, and peat bogs. These measurements are interpolated to two global grids of average Holocene and Last Glacial Maximum (LGM) climatic conditions. The interpolation is performed using a kriging algorithm and its uncertainty shows regions where new measurements are most needed. We have developed a new method that combines observational dust flux measurements with dust depositional variables from climate models to reconstruct average Holocene and LGM atmospheric dust concentrations. Here we use dust simulations from two different coupled GCMs (CAM3-CCSM3 and SPRINTARS-MIROC) to give an idea of the uncertainties due to model variables. Our reconstructions give a different perspective on Holocene and LGM atmospheric dust loads from pure model simulations. The discrepancies between modeled and reconstructed dust concentrations and radiative forcing gives insights on regions and variables that may be improved in the models. In addition, this method allows to follow the temporal and spatial evolution of dust loads (and the resulting changes in radiative forcing and iron fertilization) through the glacial-interglacial transition. Top row: Interpolated Mass Accumulation Rates (MAR) for average Holocene (left column) and Last Glacial Maximum (right column) climatic conditions. The second and third row show simulated MAR from two different coupled climate models.

  1. Mold populations and dust mite allergen concentrations in house dust samples from across Puerto Rico.

    PubMed

    Vesper, Stephen; Choi, Hyunok; Perzanowski, Matthew S; Acosta, Luis M; Divjan, Adnan; Bolaños-Rosero, Benjamin; Rivera-Mariani, Felix; Chew, Ginger L

    2016-01-01

    Lifetime childhood asthma prevalence (LCAP) percentages in Puerto Rico Health Regions (HR) are substantially higher in northeastern vs. southwestern HR. Higher average relative humidity in the northeast might promote mold and mite exposures and possibly asthma prevalence. To test this hypothesis, mold contamination, Environmental Relative Moldiness Index (ERMI) values were measured in floor dust (n = 26) and dust mite allergen concentrations in bed dust (n = 14). For this analysis, the eight HR were divided into those with LCAP > 30% (n = 3) and <  30% (n = 5). The average ERMI value was significantly greater (Wilcoxon Rank Sum, p < 0.001) in high than in low LCAP HR (14.5 vs. 9.3). The dust mite antigens Der p 1, Der f 1, and Blo t 5 were detected in 90% of bed samples, but the concentrations were not significantly different in high vs. low LCAP HR. Mold exposures might partially explain the differences in LCAP HR in Puerto Rico.

  2. A literature review of concentrations and size distributions of ambient airborne Pb-containing particulate matter

    NASA Astrophysics Data System (ADS)

    Cho, Seung-Hyun; Richmond-Bryant, Jennifer; Thornburg, Jonathan; Portzer, Jeff; Vanderpool, Robert; Cavender, Kevin; Rice, Joann

    2011-09-01

    The final 2008 lead (Pb) national ambient air quality standards (NAAQS) revision maintains Pb in total suspended particulate matter as the indicator. However, the final rule permits the use of low-volume PM 10 (particulate matter sampled with a 50% cut-point of 10 μm) Federal Reference Method (FRM) monitors in lieu of total suspended particulate (TSP) monitors for some non-source-oriented monitoring. PM 10 FRM monitors are known to provide more reliable concentration measurements than TSP samplers because they are omni-directional samplers and so are not biased by wind conditions. However, by design they exclude the upper tail of the particle size distribution. Hence, each monitor produces uncertainties about measured concentrations of Pb-bearing PM. Uncertainties in reported Pb data are also related to spatiotemporal variation of the concentration and size distribution of Pb-bearing PM. Therefore, a comprehensive literature review was performed to summarize the current knowledge regarding the concentration and size distribution of Pb particles in the atmosphere. The objectives of this review were to compile data that could shed light on these uncertainties, to provide insights useful during future Pb NAAQS reviews, and to identify areas where more research is needed. Results of this review indicated that Pb size distribution data are relatively limited and often outdated. Thirty-nine articles were found to have sufficiently detailed information regarding airborne Pb concentrations, study location, sample collection methods, and analytical techniques; only 16 of those papers reported Pb concentration data for multiple size fractions. For the most part, U.S. and European studies from the last forty years illustrate that the largest mode of the size distribution of airborne particle-bound Pb has shifted to larger sizes while airborne Pb concentrations have decreased in urban areas. This shift occurred as tetraethyl Pb additives in gasoline were phased out and

  3. An environmental nuisance: odor concentrated and transported by dust.

    PubMed

    Bottcher, R W

    2001-03-01

    Intensive swine production generates odorous emissions which flow from the buildings housing the animals. High ventilation rates bring in fresh air, remove heat and moisture and enhance pork productivity. Numerous compounds contribute to the uniquely offensive odors from swine facilities, including fatty acids, amines, aromatics and sulfur compounds. Dust particles, which originate predominantly from feces and feed, can adsorb and concentrate odorants in swine facilities. In addition, organic particles can decay and generate odorous compounds. Odorants can exist in much higher concentrations in the dust particles than in equivalent volumes of air. Thus, inhalation of odorous dust and deposition of the dust particles in the mucus overlying the olfactory mucosa are likely responsible for some odor-related complaints by swine farm neighbors. Accurate prediction of odor transport and dispersion downwind from swine farms may require models of dust dispersion and correlation between dust and odorant levels. Unfortunately, many approaches to estimating odor impact currently incorporate filtering of air to remove particulate matter before sensing by humans or electronic sensors. Accelerated progress in understanding this and other 'real world' odor control problems will require methodological innovations that allow quantification of odor in response to air streams containing vapor and particulate phases.

  4. Airborne particle concentrations at schools measured at different spatial scales

    NASA Astrophysics Data System (ADS)

    Buonanno, G.; Fuoco, F. C.; Morawska, L.; Stabile, L.

    2013-03-01

    Potential adverse effects on children health may result from school exposure to airborne particles. To address this issue, measurements in terms of particle number concentration, particle size distribution and black carbon (BC) concentrations were performed in three school buildings in Cassino (Italy) and its suburbs, outside and inside of the classrooms during normal occupancy and use. Additional time resolved information was gathered on ventilation condition, classroom activity, and traffic count data around the schools were obtained using a video camera. Across the three investigated school buildings, the outdoor and indoor particle number concentration monitored down to 4 nm and up to 3 μm ranged from 2.8 × 104 part cm-3 to 4.7 × 104 part cm-3 and from 2.0 × 104 part cm-3 to 3.5 × 104 part cm-3, respectively. The total particle concentrations were usually higher outdoors than indoors, because no indoor sources were detected. I/O measured was less than 1 (varying in a relatively narrow range from 0.63 to 0.74), however one school exhibited indoor concentrations higher than outdoor during the morning rush hours. Particle size distribution at the outdoor site showed high particle concentrations in different size ranges, varying during the day; in relation to the starting and finishing of school time two modes were found. BC concentrations were 5 times higher at the urban school compared with the suburban and suburban-to-urban differences were larger than the relative differences of ultrafine particle concentrations.

  5. Airborne Nanoparticle Concentrations in the Manufacturing of Polytetrafluoroethylene (PTFE) Apparel

    PubMed Central

    Vosburgh, Donna J.H.; Boysen, Dane A.; Oleson, Jacob J.; Peters, Thomas M.

    2016-01-01

    One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric, using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600°C). This study addressed the potential for exposure to particulate matter from this sealing process, by characterizing airborne particles in a facility that produces over 1,000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm−3) compared to that measured in the office area (12,100 particles cm−3). Respirable mass concentrations were negligible throughout the facility (GM=0.002 mg m−3 in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p<0.0001). The sealing workers’ breathing zone concentrations ranged from 147,000 particles cm−3 to 798,000 particles cm−3, and their seam responsibility significantly influenced their breathing zone concentrations (p=0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations. PMID:21347955

  6. Airborne nanoparticle concentrations in the manufacturing of polytetrafluoroethylene (PTFE) apparel.

    PubMed

    Vosburgh, Donna J H; Boysen, Dane A; Oleson, Jacob J; Peters, Thomas M

    2011-03-01

    One form of waterproof, breathable apparel is manufactured from polytetrafluoroethylene (PTFE) membrane laminated fabric using a specific process to seal seams that have been sewn with traditional techniques. The sealing process involves applying waterproof tape to the seam by feeding the seam through two rollers while applying hot air (600 °C). This study addressed the potential for exposure to particulate matter from this sealing process by characterizing airborne particles in a facility that produces more than 1000 lightweight PTFE rain jackets per day. Aerosol concentrations throughout the facility were mapped, breathing zone concentrations were measured, and hoods used to ventilate the seam sealing operation were evaluated. The geometric mean (GM) particle number concentrations were substantially greater in the sewing and sealing areas (67,000 and 188,000 particles cm⁻³)) compared with that measured in the office area (12,100 particles cm⁻³). Respirable mass concentrations were negligible throughout the facility (GM = 0.002 mg m⁻³) in the sewing and sealing areas). The particles exiting the final discharge of the facility's ventilation system were dominated by nanoparticles (number median diameter = 25 nm; geometric standard deviation of 1.39). The breathing zone particle number concentrations of the workers who sealed the sewn seams were highly variable and significantly greater when sealing seams than when conducting other tasks (p < 0.0001). The sealing workers' breathing zone concentrations ranged from 147,000 particles cm⁻³ to 798,000 particles cm⁻³, and their seam responsibility significantly influenced their breathing zone concentrations (p = 0.03). The finding that particle number concentrations were approximately equal outside the hood and inside the local exhaust duct indicated poor effectiveness of the canopy hoods used to ventilate sealing operations.

  7. Distribution analysis of airborne nicotine concentrations in hospitality facilities.

    PubMed

    Schorp, Matthias K; Leyden, Donald E

    2002-02-01

    A number of publications report statistical summaries for environmental tobacco smoke (ETS) concentrations. Despite compelling evidence for the data not being normally distributed, these publications typically report the arithmetic mean and standard deviation of the data, thereby losing important information related to the distribution of values contained in the original data. We were interested in the frequency distributions of reported nicotine concentrations in hospitality environments and subjected available data to distribution analyses. The distribution of experimental indoor airborne nicotine concentration data taken from hospitality facilities worldwide was fit to lognormal, Weibull, exponential, Pearson (Type V), logistic, and loglogistic distribution models. Comparison of goodness of fit (GOF) parameters and indications from the literature verified the selection of a lognormal distribution as the overall best model. When individual data were not reported in the literature, statistical summaries of results were used to model sets of lognormally distributed data that are intended to mimic the original data distribution. Grouping the data into various categories led to 31 frequency distributions that were further interpreted. The median values in nonsmoking environments are about half of the median values in smoking sections. When different continents are compared, Asian, European, and North American median values in restaurants are about a factor of three below levels encountered in other hospitality facilities. On a comparison of nicotine concentrations in North American smoking sections and nonsmoking sections, median values are about one-third of the European levels. The results obtained may be used to address issues related to exposure to ETS in the hospitality sector.

  8. Retrospective view of airborne dust levels in workplace of a chrysotile mine in Ural, Russia.

    PubMed

    Kashansky, S V; Domnin, S G; Kochelayev, V A; Monakhov, D D; Kogan, F M

    2001-04-01

    The Bazhenovskoye chrysotile asbestos deposit has been exploited for 115 years. All the technological operations in the quarry are accompanied by the formation of high-dispersion asbestos-containing aerosols. The dust concentrations at the miner's working places for the last 30 years (1970-2000) were at or below the Russian MACs(m.s.) level (4.0 mg/m3). The seasonal precipitation amount in the deposit area causes a rise in dust content in certain periods. The maximum density of asbestos respirable fibres exceeded 2.7 f/cm3. All the identified fibres belonged to chrysotile asbestos, and no amphibole asbestos, such as tremolite asbestos, has been identified. An excessive dust level remains, despite the dust content level decrease, at the work sites of oversized lump drillers and unloaders, and oncopathology heightened risk remains in these occupational groups, as a result.

  9. Compact Dust Concentration in the MWC 758 Protoplanetary Disk

    NASA Astrophysics Data System (ADS)

    Marino, S.; Casassus, S.; Perez, S.; Lyra, W.; Roman, P. E.; Avenhaus, H.; Wright, C. M.; Maddison, S. T.

    2015-11-01

    The formation of planetesimals requires that primordial dust grains grow from micron- to kilometer-sized bodies. Dust traps caused by gas pressure maxima have been proposed as regions where grains can concentrate and grow fast enough to form planetesimals, before radially migrating onto the star. We report new VLA Ka and Ku observations of the protoplanetary disk around the Herbig Ae/Be star MWC 758. The Ka image shows a compact emission region in the outer disk, indicating a strong concentration of big dust grains. Tracing smaller grains, archival ALMA data in band 7 continuum shows extended disk emission with an intensity maximum to the northwest of the central star, which matches the VLA clump position. The compactness of the Ka emission is expected in the context of dust trapping, as big grains are trapped more easily than smaller grains in gas pressure maxima. We develop a nonaxisymmetric parametric model inspired by a steady-state vortex solution with parameters adequately selected to reproduce the observations, including the spectral energy distribution. Finally, we compare the radio continuum with SPHERE scattered light data. The ALMA continuum spatially coincides with a spiral-like feature seen in scattered light, while the VLA clump is offset from the scattered light maximum. Moreover, the ALMA map shows a decrement that matches a region devoid of scattered polarized emission. Continuum observations at a different wavelength are necessary to conclude whether the VLA-ALMA difference is an opacity or a real dust segregation.

  10. COMPACT DUST CONCENTRATION IN THE MWC 758 PROTOPLANETARY DISK

    SciTech Connect

    Marino, S.; Casassus, S.; Perez, S.; Avenhaus, H.; Lyra, W.; Roman, P. E.; Wright, C. M.; Maddison, S. T.

    2015-11-01

    The formation of planetesimals requires that primordial dust grains grow from micron- to kilometer-sized bodies. Dust traps caused by gas pressure maxima have been proposed as regions where grains can concentrate and grow fast enough to form planetesimals, before radially migrating onto the star. We report new VLA Ka and Ku observations of the protoplanetary disk around the Herbig Ae/Be star MWC 758. The Ka image shows a compact emission region in the outer disk, indicating a strong concentration of big dust grains. Tracing smaller grains, archival ALMA data in band 7 continuum shows extended disk emission with an intensity maximum to the northwest of the central star, which matches the VLA clump position. The compactness of the Ka emission is expected in the context of dust trapping, as big grains are trapped more easily than smaller grains in gas pressure maxima. We develop a nonaxisymmetric parametric model inspired by a steady-state vortex solution with parameters adequately selected to reproduce the observations, including the spectral energy distribution. Finally, we compare the radio continuum with SPHERE scattered light data. The ALMA continuum spatially coincides with a spiral-like feature seen in scattered light, while the VLA clump is offset from the scattered light maximum. Moreover, the ALMA map shows a decrement that matches a region devoid of scattered polarized emission. Continuum observations at a different wavelength are necessary to conclude whether the VLA-ALMA difference is an opacity or a real dust segregation.

  11. Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants. Volume 2

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The National Aeronautics and Space Administration (NASA) is aware of the potential toxicological hazards to humans that might be associated with prolonged spacecraft missions. Despite major engineering advances in controlling the atmosphere within spacecraft, some contamination of the air appears inevitable. NASA has measured numerous airborne contaminants during space missions. As the missions increase in duration and complexity, ensuring the health and well-being of astronauts traveling and working in this unique environment becomes increasingly difficult. As part of its efforts to promote safe conditions aboard spacecraft, NASA requested the National Research Council (NRC) to develop guidelines for establishing spacecraft maximum allowable concentrations (SMACs) for contaminants, and to review SMACs for various space-craft contaminants to determine whether NASA's recommended exposure limits are consistent with the guidelines recommended by the subcommittee. In response to NASA's request, the NRC organized the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants within the Committee On Toxicology (COT). In the first phase of its work, the subcommittee developed the criteria and methods for preparing SMACs for spacecraft contaminants. The subcommittee's report, entitled Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants, was published in 1992. The executive summary of that report is reprinted as Appendix A of this volume. In the second phase of the study, the Subcommittee on Spacecraft Maximum Allowable Concentrations reviewed reports prepared by NASA scientists and contractors recommending SMACs for approximately 35 spacecraft contaminants. The subcommittee sought to determine whether the SMAC reports were consistent with the 1992 guidelines. Appendix B of this volume contains the SMAC reports for 12 chemical contaminants that have been reviewed for

  12. Modelling airborne concentration and deposition rate of maize pollen

    NASA Astrophysics Data System (ADS)

    Jarosz, Nathalie; Loubet, Benjamin; Huber, Laurent

    2004-10-01

    The introduction of genetically modified (GM) crops has reinforced the need to quantify gene flow from crop to crop. This requires predictive tools which take into account meteorological conditions, canopy structure as well as pollen aerodynamic characteristics. A Lagrangian Stochastic (LS) model, called SMOP-2D (Stochastic Mechanistic model for Pollen dispersion and deposition in 2 Dimensions), is presented. It simulates wind dispersion of pollen by calculating individual pollen trajectories from their emission to their deposition. SMOP-2D was validated using two field experiments where airborne concentration and deposition rate of pollen were measured within and downwind from different sized maize (Zea mays) plots together with micrometeorological measurements. SMOP-2D correctly simulated the shapes of the concentration profiles but generally underestimated the deposition rates in the first 10 m downwind from the source. Potential explanations of this discrepancy are discussed. Incorrect parameterisation of turbulence in the transition from the crop to the surroundings is probably the most likely reason. This demonstrates that LS models for particle transfer need to be coupled with air-flow models under complex terrain conditions.

  13. Saharan Dust Particle Size And Concentration Distribution In Central Ghana

    NASA Astrophysics Data System (ADS)

    Sunnu, A. K.

    2010-12-01

    A.K. Sunnu*, G. M. Afeti* and F. Resch+ *Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology (KNUST) Kumasi, Ghana. E-mail: albertsunnu@yahoo.com +Laboratoire Lepi, ISITV-Université du Sud Toulon-Var, 83162 La Valette cedex, France E-mail: resch@univ-tln.fr Keywords: Atmospheric aerosol; Saharan dust; Particle size distributions; Particle concentrations. Abstract The Saharan dust that is transported and deposited over many countries in the West African atmospheric environment (5°N), every year, during the months of November to March, known locally as the Harmattan season, have been studied over a 13-year period, between 1996 and 2009, using a location at Kumasi in central Ghana (6° 40'N, 1° 34'W) as the reference geographical point. The suspended Saharan dust particles were sampled by an optical particle counter, and the particle size distributions and concentrations were analysed. The counter gives the total dust loads as number of particles per unit volume of air. The optical particle counter used did not discriminate the smoke fractions (due to spontaneous bush fires during the dry season) from the Saharan dust. Within the particle size range measured (0.5 μm-25 μm.), the average inter-annual mean particle diameter, number and mass concentrations during the northern winter months of January and February were determined. The average daily number concentrations ranged from 15 particles/cm3 to 63 particles/cm3 with an average of 31 particles/cm3. The average daily mass concentrations ranged from 122 μg/m3 to 1344 μg/m3 with an average of 532 μg/m3. The measured particle concentrations outside the winter period were consistently less than 10 cm-3. The overall dust mean particle diameter, analyzed from the peak representative Harmattan periods over the 13-year period, ranged from 0.89 μm to 2.43 μm with an average of 1.5 μm ± 0.5. The particle size distributions exhibited the typical distribution pattern for

  14. Measurement of airborne particle concentrations near the Sunset Crater volcano, Arizona.

    PubMed

    Benke, Roland R; Hooper, Donald M; Durham, James S; Bannon, Donald R; Compton, Keith L; Necsoiu, Marius; McGinnis, Ronald N

    2009-02-01

    Direct measurements of airborne particle mass concentrations or mass loads are often used to estimate health effects from the inhalation of resuspended contaminated soil. Airborne particle mass concentrations were measured using a personal sampler under a variety of surface-disturbing activities within different depositional environments at both volcanic and nonvolcanic sites near the Sunset Crater volcano in northern Arizona. Focused field investigations were performed at this analog site to improve the understanding of natural and human-induced processes at Yucca Mountain, Nevada. The level of surface-disturbing activity was found to be the most influential factor affecting the measured airborne particle concentrations, which increased over three orders of magnitude relative to ambient conditions. As the surface-disturbing activity level increased, the particle size distribution and the majority of airborne particle mass shifted from particles with aerodynamic diameters less than 10 mum (0.00039 in) to particles with aerodynamic diameters greater than 10 mum (0.00039 in). Under ambient conditions, above average wind speeds tended to increase airborne particle concentrations. In contrast, stronger winds tended to decrease airborne particle concentrations in the breathing zone during light and heavy surface-disturbing conditions. A slight increase in the average airborne particle concentration during ambient conditions was found above older nonvolcanic deposits, which tended to be finer grained than the Sunset Crater tephra deposits. An increased airborne particle concentration was realized when walking on an extremely fine-grained deposit, but the sensitivity of airborne particle concentrations to the resuspendible fraction of near-surface grain mass was not conclusive in the field setting when human activities disturbed the bulk of near-surface material. Although the limited sample size precluded detailed statistical analysis, the differences in airborne particle

  15. Species-specific Fungal DNA in Airborne Dust as Surrogate for Occupational Mycotoxin Exposure?

    PubMed Central

    Halstensen, Anne Straumfors

    2008-01-01

    Possible health risks associated with occupational inhalation of mycotoxin-containing dust remain largely unknown, partly because methods for mycotoxin detection are not sensitive enough for the small dust masses obtained by personal sampling, which is needed for inhalable exposure measurements. Specific and sensitive PCR detection of fungi with mycotoxin-producing potential seem to be a good surrogate for occupational exposure measurements that include all fungal structures independent of morphology and cultivability. Results should, however, be interpreted with caution due to variable correlations with mycotoxin concentrations. PMID:19330091

  16. Concentrations and size distribution of inhalable and respirable dust among sugar industry workers: a pilot study in Khon Kaen, Thailand.

    PubMed

    Sakunkoo, Pornpun; Chaiear, Naesinee; Chaikittiporn, Chalermchai; Sadhra, Steven

    2011-11-01

    There has been very limited information regarding bagasse exposure among workers in sugar industries as well as on health outcomes. The authors determined the occupational exposure of sugar industry workers in Khon Kaen to airborne bagasse dust. The size of the bagasse dust ranged from 0.08 to 9 µm with the highest size concentration of 2.1 to 4.7 µm. The most common size had a geometric mean diameter of 5.2 µm, with a mass concentration of 6.89 mg/m(3)/log µm. The highest mean values of inhalable and respirable dust were found to be 9.29 mg/m(3) from February to April in bagasse storage, 5.12 mg/m(3) from May to September, and 4.12 mg/m(3) from October to January. Inhalable dust concentrations were 0.33, 0.47, and 0.41 mg/m(3), respectively. Workers are likely to be exposed to high concentrations of bagasse dust and are at risk of respiratory diseases. Preventive measures, both in the form of engineering designs and personal protective devices, should be implemented.

  17. Characteristics of airborne ultrafine and coarse particles during the Australian dust storm of 23 September 2009

    NASA Astrophysics Data System (ADS)

    Jayaratne, E. R.; Johnson, G. R.; McGarry, P.; Cheung, H. C.; Morawska, L.

    2011-08-01

    Particle number concentrations and size distributions, visibility and particulate mass concentrations and weather parameters were monitored in Brisbane, Australia, on 23 September 2009, during the passage of a dust storm that originated 1400 km away in the dry continental interior. The dust concentration peaked at about mid-day when the hourly average PM 2.5 and PM 10 values reached 814 and 6460 μg m -3, respectively, with a sharp drop in atmospheric visibility. A linear regression analysis showed a good correlation between the coefficient of light scattering by particles (Bsp) and both PM 10 and PM 2.5. The particle number in the size range 0.5-20 μm exhibited a lognormal size distribution with modal and geometrical mean diameters of 1.6 and 1.9 μm, respectively. The modal mass was around 10 μm with less than 10% of the mass carried by particles smaller than 2.5 μm. The PM 10 fraction accounted for about 68% of the total mass. By mid-day, as the dust began to increase sharply, the ultrafine particle number concentration fell from about 6 × 10 3 cm -3 to 3 × 10 3 cm -3 and then continued to decrease to less than 1 × 10 3 cm -3 by 14 h, showing a power-law decrease with Bsp with an R2 value of 0.77 ( p < 0.01). Ultrafine particle size distributions also showed a significant decrease in number during the dust storm. This is the first scientific study of particle size distributions in an Australian dust storm.

  18. 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.

  19. Kaolin dust concentrations and pneumoconiosis at a kaolin mine.

    PubMed Central

    Altekruse, E B; Chaudhary, B A; Pearson, M G; Morgan, W K

    1984-01-01

    Kaolin is removed from underground seams in the mining area to a processing area, where it is sliced, dried, and pulverised to make the finished product. A study was undertaken to determine the dust concentrations in various work areas and to assess the prevalence of radiographic and pulmonary function abnormalities in 65 workers at a Georgia kaolin mine. Respirable dust concentrations were higher in the processing area than in the mine or maintenance areas for all determinations from 1977 to 1981. The mean respirable dust level in the processing area in 1981 was 1.74 mg/m3 and 0.14 mg/m3 in the mine area. Five workers, all of whom had worked at the processing area, had radiographic evidence of kaolin pneumoconiosis. The mean values of forced vital capacity (FVC) and FEV1 of the entire group were within the normal range. When the spirometric values were expressed as a percentage of the predicted values, the FVC and FEV1 were significantly lower in the workers with kaolinosis than in other workers in the processing area. The FVC and FEV1 also declined significantly with increasing years of work in the processing area. The FEV1/FVC%, however, was not significantly altered either by the presence of kaolinosis or by an increasing number of years of work, indicating that the impairment was restrictive and hence likely to be a consequence of dust inhalation rather than smoking. In this study the highest dust concentrations occurred in the processing area, and kaolin pneumoconiosis was limited to those who had worked there. Kaolin exposure appeared to have a small but significant effect on ventilatory capacity in those with kaolin pneumoconiosis and in workers with a longer exposure. There was no association between the radiographic appearances of kaolinosis and cigarette smoking or between the presence of radiographic abnormalities and reduced arterial blood gas tensions. Images PMID:6463912

  20. 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

  1. Concentrations, sources and geochemistry of airborne particulate matter at a major European airport.

    PubMed

    Amato, Fulvio; Moreno, Teresa; Pandolfi, Marco; Querol, Xavier; Alastuey, Andrés; Delgado, Ana; Pedrero, Manuel; Cots, Nuria

    2010-04-01

    Monitoring of aerosol particle concentrations (PM(10), PM(2.5), PM(1)) and chemical analysis (PM(10)) was undertaken at a major European airport (El Prat, Barcelona) for a whole month during autumn 2007. Concentrations of airborne PM at the airport were close to those at road traffic hotspots in the nearby Barcelona city, with means measuring 48 microg PM(10)/m(3), 21 microg PM(2.5)/m(3) and 17 microg PM(1)/m(3). Meteorological controls on PM at El Prat are identified as cleansing daytime sea breezes with abundant coarse salt particles, alternating with nocturnal land-sourced winds which channel air polluted by industry and traffic (PM(1)/PM(10) ratios > 0.5) SE down the Llobregat Valley. Chemical analyses of the PM(10) samples show that crustal PM is dominant (38% of PM(10)), followed by total carbon (OC + EC, 25%), secondary inorganic aerosols (SIA, 20%), and sea salt (6%). Local construction work for a new airport terminal was an important contributor to PM(10) crustal levels. Source apportionment modelling PCA-MLRA identifies five factors: industrial/traffic, crustal, sea salt, SIA, and K(+) likely derived from agricultural biomass burning. Whereas most of the atmospheric contamination concerning ambient air PM(10) levels at El Prat is not attributable directly to aircraft movement, levels of carbon are unusually high (especially organic carbon), as are metals possibly sourced from tyre detritus/smoke in runway dust (Ba, Zn, Mo) and from brake dust in ambient PM(10) (Cu, Sb), especially when the airport is at its most busy. We identify microflakes of aluminous alloys in ambient PM(10) filters derived from corroded fuselage and wings as an unequivocal and highly distinctive tracer for aircraft movement.

  2. Dust Transport Across the Atlantic Studied by Airborne Doppler Wind Lidar During the Saltrace Experiment in 2013

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Rahm, Stephan; Weinzierl, Bernadett

    2016-06-01

    During the SALTRACE field experiment, conducted during June/July 2013, the Saharan dust transport across the Atlantic was analyzed by a set of ground based, in-situ and airborne instruments, including a 2-μm coherent DWL (Doppler wind lidar) mounted onboard the DLR Falcon 20 research aircraft. An overview of the measurements of aerosol backscatter and extinction, horizontal and vertical winds retrieved from the DWL are presented together with a brief description of the applied methods. The retrieved measurements provide direct observation of Saharan dust transport mechanisms across the Atlantic as well as island induced lee waves in the Barbados region.

  3. Determination of airborne wood dust in Button samples by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).

    PubMed

    Kwon, Cheol-Woong; Chirila, Madalina M; Lee, Taekhee; Harper, Martin; Rando, Roy J

    2013-01-01

    Emerging concerns regarding the toxicity of inhaled wood dust support the need for techniques to quantitate wood content of mixed industrial dusts. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis technique was applied to the determination of wood content of 181 inhalable dust samples (geometric mean concentration: 0.895 mg/m(3); geometric standard deviation: 2.73) collected from six wood product industry factories using 25mm glass fibre filters with the Button aerosol sampler. Prior to direct DRIFTS analysis the filter samples were treated with ethyl acetate and re-deposited uniformly. Standards ranging from 125 μg to 4000 μg were prepared for red oak, southern yellow pine, and red cedar and used for quantitation of samples depending upon the wood materials present at a given factory. The oak standards spectra were quantitated by linear regression of response in Kubelka-Munk units at 1736 cm(-1), whereas the pine standards and the cedar standards spectra were quantitated by polynomial regression of response in log 1/R units at 1734 cm(-1), with the selected wavenumbers corresponding to stretching vibration of free C=O from cellulose and hemicelluloses. For one factory which used both soft- and hardwoods, a separate polynomial standard curve was created by proportionally combining the oak and pine standards polynomial regression equations based on response (log 1/R) at 1734 cm(-1). The analytical limits of detection were approximately 52 μg of oak, 20 μg of pine, 30 μg of cedar, and 16 μg of mixed oak and pine for the factory with mixed woods. Overall, the average of dry wood dust percentage of inhalable dust was approximately 56% and the average dry wood dust weight was 0.572mg for the Button samples. Across factories, there were statistically significant differences (p<0.001) for the percentage of dry wood dust in inhalable dust with factory averages ranging from 33.5 to 97.6%.

  4. Determination of airborne wood dust in Button samples by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)

    PubMed Central

    Kwon, Cheol-Woong; Chirila, Madalina M.; Lee, Taekhee; Harper, Martin; Rando, Roy J.

    2015-01-01

    Emerging concerns regarding the toxicity of inhaled wood dust support the need for techniques to quantitate wood content of mixed industrial dusts. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis technique was applied to the determination of wood content of 181 inhalable dust samples (geometric mean concentration: 0.895 mg/m3; geometric standard deviation: 2.73) collected from six wood product industry factories using 25mm glass fibre filters with the Button aerosol sampler. Prior to direct DRIFTS analysis the filter samples were treated with ethyl acetate and re-deposited uniformly. Standards ranging from 125 μg to 4000 μg were prepared for red oak, southern yellow pine, and red cedar and used for quantitation of samples depending upon the wood materials present at a given factory. The oak standards spectra were quantitated by linear regression of response in Kubelka-Munk units at 1736 cm−1, whereas the pine standards and the cedar standards spectra were quantitated by polynomial regression of response in log 1/R units at 1734 cm−1, with the selected wavenumbers corresponding to stretching vibration of free C=O from cellulose and hemicelluloses. For one factory which used both soft- and hardwoods, a separate polynomial standard curve was created by proportionally combining the oak and pine standards polynomial regression equations based on response (log 1/R) at 1734 cm−1. The analytical limits of detection were approximately 52 μg of oak, 20 μg of pine, 30 μg of cedar, and 16 μg of mixed oak and pine for the factory with mixed woods. Overall, the average of dry wood dust percentage of inhalable dust was approximately 56% and the average dry wood dust weight was 0.572mg for the Button samples. Across factories, there were statistically significant differences (p<0.001) for the percentage of dry wood dust in inhalable dust with factory averages ranging from 33.5 to 97.6%. PMID:26526539

  5. 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.

  6. Effect of Wind Speed and Relative Humidity on Atmospheric Dust Concentrations in Semi-Arid Climates

    PubMed Central

    Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y.; Sáez, A. Eduardo; Betterton, Eric A.

    2014-01-01

    Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (> 4 m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport. PMID:24769193

  7. Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates.

    PubMed

    Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y; Sáez, A Eduardo; Betterton, Eric A

    2014-07-15

    Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (>4m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport.

  8. 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.

  9. Atmospheric and surface temperatures and airborne dust amounts during late southern summer from Mariner 9 IRIS data

    NASA Technical Reports Server (NTRS)

    Santee, M.; Crisp, D.

    1992-01-01

    The temperature structure and dust loading of the Martian atmosphere are investigated using thermal emission spectra recorded in 1972 by the Mariner 9 infrared interferometer spectrometer (IRIS). The analysis focuses on a subset of data consisting of approximately 2400 spectra obtained near the end of the southern summer season (L(sub s) equal to 343 deg to 348 deg), after the global dust storm had largely abated and airborne dust amounts were subsiding to background values. Simultaneous retrieval of the vertical distribution of both atmospheric temperature and dust optical depth is accomplished through an iterative procedure which is performed on each individual spectrum. The atmospheric transmittances are calculated using a Voigt quasi-random band model, which includes absorption by CO2 and dust, but neglects the effects of multiple scattering. Vertical profiles of temperature and dust optical depth are obtained using modified algorithms. These profiles are used to construct global maps of temperature and dust optical depth as functions of latitude (+/- 90 deg), altitude (approximately 0-50 km), and local time of day.

  10. Modeling of surface dust concentrations using neural networks and kriging

    NASA Astrophysics Data System (ADS)

    Buevich, Alexander G.; Medvedev, Alexander N.; Sergeev, Alexander P.; Tarasov, Dmitry A.; Shichkin, Andrey V.; Sergeeva, Marina V.; Atanasova, T. B.

    2016-12-01

    Creating models which are able to accurately predict the distribution of pollutants based on a limited set of input data is an important task in environmental studies. In the paper two neural approaches: (multilayer perceptron (MLP)) and generalized regression neural network (GRNN)), and two geostatistical approaches: (kriging and cokriging), are using for modeling and forecasting of dust concentrations in snow cover. The area of study is under the influence of dust emissions from a copper quarry and a several industrial companies. The comparison of two mentioned approaches is conducted. Three indices are used as the indicators of the models accuracy: the mean absolute error (MAE), root mean square error (RMSE) and relative root mean square error (RRMSE). Models based on artificial neural networks (ANN) have shown better accuracy. When considering all indices, the most precision model was the GRNN, which uses as input parameters for modeling the coordinates of sampling points and the distance to the probable emissions source. The results of work confirm that trained ANN may be more suitable tool for modeling of dust concentrations in snow cover.

  11. Factors affecting vegetable growers' exposure to fungal bioaerosols and airborne dust.

    PubMed

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

    2012-03-01

    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.

  12. Gas and dust hydrodynamical simulations of massive lopsided transition discs - II. Dust concentration

    NASA Astrophysics Data System (ADS)

    Baruteau, Clément; Zhu, Zhaohuan

    2016-06-01

    We investigate the dynamics of large dust grains in massive lopsided transition discs via 2D hydrodynamical simulations including both gas and dust. Our simulations adopt a ring-like gas density profile that becomes unstable against the Rossby-wave instability and forms a large crescent-shaped vortex. When gas self-gravity is discarded, but the indirect force from the displacement of the star by the vortex is included, we confirm that dust grains with stopping times of order the orbital time, which should be typically a few centimetres in size, are trapped ahead of the vortex in the azimuthal direction, while the smallest and largest grains concentrate towards the vortex centre. We obtain maximum shift angles of about 25°. Gas self-gravity accentuates the concentration differences between small and large grains. At low to moderate disc masses, the larger the grains, the farther they are trapped ahead of the vortex. Shift angles up to 90° are reached for 10 cm-sized grains, and we show that such large offsets can produce a double-peaked continuum emission observable at mm/cm wavelengths. This behaviour comes about because the large grains undergo horseshoe U-turns relative to the vortex due to the vortex's gravity. At large disc masses, since the vortex's pattern frequency becomes increasingly slower than Keplerian, small grains concentrate slightly beyond the vortex and large grains form generally non-axisymmetric ring-like structures around the vortex's radial location. Gas self-gravity therefore imparts distinct trapping locations for small and large dust grains, which may be probed by current and future observations.

  13. Microbial analyses of airborne dust collected from dormitory rooms predict the sex of occupants.

    PubMed

    Luongo, J C; Barberán, A; Hacker-Cary, R; Morgan, E E; Miller, S L; Fierer, N

    2017-03-01

    We have long known that human occupants are a major source of microbes in the built environment, thus raising the question: How much can we learn about the occupants of a building by analyzing the microbial communities found in indoor air? We investigated bacterial and fungal diversity found in airborne dust collected onto heating, ventilation, and air-conditioning (HVAC) air filters and settling plates from 91 rooms within a university dormitory. The sex of the room occupants had the most significant effect on the bacterial communities, while the room occupants had no significant effect on fungal communities. By examining the abundances of bacterial genera, we could predict the sex of room occupants with 79% accuracy, a finding that demonstrates the potential forensic applications of studying indoor air microbiology. We also identified which bacterial taxa were indicators of female and male rooms, and found that those taxa often identified as members of the vaginal microbiome were more common in female-occupied rooms while taxa associated with human skin or the male urogenital microbiota were more common in male-occupied rooms.

  14. 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.

  15. A Quantitative Dynamic Simulation of Bremia lactucae Airborne Conidia Concentration above a Lettuce Canopy

    PubMed Central

    Fall, Mamadou Lamine; Van der Heyden, Hervé; Carisse, Odile

    2016-01-01

    Lettuce downy mildew, caused by the oomycete Bremia lactucae Regel, is a major threat to lettuce production worldwide. Lettuce downy mildew is a polycyclic disease driven by airborne spores. A weather-based dynamic simulation model for B. lactucae airborne spores was developed to simulate the aerobiological characteristics of the pathogen. The model was built using the STELLA platform by following the system dynamics methodology. The model was developed using published equations describing disease subprocesses (e.g., sporulation) and assembled knowledge of the interactions among pathogen, host, and weather. The model was evaluated with four years of independent data by comparing model simulations with observations of hourly and daily airborne spore concentrations. The results show an accurate simulation of the trend and shape of B. lactucae temporal dynamics of airborne spore concentration. The model simulated hourly and daily peaks in airborne spore concentrations. More than 95% of the simulation runs, the daily-simulated airborne conidia concentration was 0 when airborne conidia were not observed. Also, the relationship between the simulated and the observed airborne spores was linear. In more than 94% of the simulation runs, the proportion of the linear variation in the hourly-observed values explained by the variation in the hourly-simulated values was greater than 0.7 in all years except one. Most of the errors came from the deviation from the 1:1 line, and the proportion of errors due to the model bias was low. This model is the only dynamic model developed to mimic the dynamics of airborne inoculum and represents an initial step towards improved lettuce downy mildew understanding, forecasting and management. PMID:26953691

  16. 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.

  17. 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.

  18. Magnetic properties and element concentrations in lichens exposed to airborne pollutants released during cement production.

    PubMed

    Paoli, Luca; Winkler, Aldo; Guttová, Anna; Sagnotti, Leonardo; Grassi, Alice; Lackovičová, Anna; Senko, Dušan; Loppi, Stefano

    2016-02-15

    The content of selected elements (Al, As, Ca, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, S, Ti, V and Zn) was measured in samples of the lichen Evernia prunastri exposed for 30, 90 and 180 days around a cement mill, limestone and basalt quarries and urban and agricultural areas in SW Slovakia. Lichens transplanted around the investigated quarries and the cement mill rapidly (30 days) reflected the deposition of dust-associated elements, namely Ca (at the cement mill and the limestone quarry) and Fe, Ti and V (around the cement mill and the basalt quarry), and their content remained significantly higher throughout the whole period (30-180 days) with respect to the surrounding environment. Airborne pollutants (such as S) progressively increased in the study area from 30 to 180 days. The magnetic properties of lichen transplants exposed for 180 days have been characterized and compared with those of native lichens (Xanthoria parietina) and neighbouring bark, soil and rock samples, in order to test the suitability of native and transplanted samples as air pollution magnetic biomonitors. The magnetic mineralogy was homogeneous in all samples, with the exception of the samples from the basalt quarry. The transplants showed excellent correlations between the saturation remanent magnetization (Mrs) and the content of Fe. Native samples had a similar magnetic signature, but the values of the concentration-dependent magnetic parameters were up to two orders of magnitude higher, reflecting higher concentrations of magnetic particles. The concentrations of As, Ca and Cr in lichens correlated with Mrs values after neglecting the samples from the basalt quarry, which showed distinct magnetic properties, suggesting the cement mill as a likely source. Conversely, Ti and Mn were mostly (but not exclusively) associated with dust from the basalt quarry. It is suggested that the natural geological characteristics of the substrate may strongly affect the magnetic properties of lichen thalli

  19. Comparison of Lead Species in Household Dust Wipes, Soil, and Airborne Particulate Matter in El Paso, Texas, by X-Ray Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Clague, J.; Amaya, M. A.

    2006-12-01

    Understanding the interplay of indoor and outdoor sources of lead in an urban setting is one foundation in establishing risk for lead exposure in children in our cities. A household may be the source for lead contamination due to the deterioration of interior lead-based paint, or a sink if lead particles are tracked or blown into the home from such potential ambient sources as yard soil or urban street dust. In addressing this issue, X-Ray Absorption Spectroscopy (XAS) presents the opportunity to directly and quantitatively speciate lead at low concentrations in bulk samples. We performed XAS analyses on dust wipes from window sills or floors from 8 houses that exceeded Federal standards for lead in dust. We entered these data into a Principal Components Analysis (PCA) that also included El Paso environmental samples: lead-based paints, soils, and airborne particulate matter. A simple two-component mixing system accounted for more than 95% of the variance of this data set. Paint and lead oxide appear to be the principal components, with all the samples falling in a compositional range from pure paint to 75% paint, 25% lead oxide. Note that several different lead compounds are possible constituents of a given lead-based paint. The paints spread from one end out along perhaps a fifth of the range of the compositional axis, followed closely, but not overlapped, by the soil samples, which covered the remainder of the compositional range. Two of the dust wipes plotted within the paint range, and the remaining 6 dust wipes plotted randomly through the soil range. Samples of airborne particulate matter plotted in both the paint and soil ranges. These observations suggest that the lead on most of the dust wipes originated outside the house, probably from deteriorated exterior lead-based paint deposited in adjacent yards. This paint mixed with lead oxide present in the soil and entered the houses by the airborne route. The probable source of the oxide in the soil is former

  20. 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.

  1. Absolute tracer dye concentration using airborne laser-induced water Raman backscatter

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1981-01-01

    The use of simultaneous airborne-laser-induced dye fluorescence and water Raman backscatter to measure the absolute concentration of an ocean-dispersed tracer dye is discussed. Theoretical considerations of the calculation of dye concentration by the numerical comparison of airborne laser-induced fluorescence spectra with laboratory spectra for known dye concentrations using the 3400/cm OH-stretch water Raman scatter as a calibration signal are presented which show that minimum errors are obtained and no data concerning water mass transmission properties are required when the laser wavelength is chosen to yield a Raman signal near the dye emission band. Results of field experiments conducted with an airborne conical scan lidar over a site in New York Bight into which rhodamine dye had been injected in a study of oil spill dispersion are then indicated which resulted in a contour map of dye concentrations, with a minimum detectable dye concentration of approximately 2 ppb by weight.

  2. How reliable are crystalline silica dust concentration measurements?

    PubMed

    Cox, L A; Van Orden, D R; Lee, R J; Arlauckas, S M; Kautz, R A; Warzel, A L; Bailey, K F; Ranpuria, A K

    2015-10-01

    To determine how reliably commercial laboratories measure crystalline silica concentrations corresponding to OSHA's proposed limits, 105 filters were prepared with known masses of 20, 40, and 80 μg of respirable quartz corresponding to airborne silica concentrations of 25, 50, and 100 μg/m(3) and were submitted, in a blind test, to qualified commercial laboratories over a nine month period. Under these test conditions, the reported results indicated a lack of accuracy and precision needed to reliably inform regulatory compliance decisions. This was true even for filters containing only silica, without an interfering matrix. For 36 filters loaded with 20 or more micrograms of silica, the laboratories reported non-detected levels of silica. Inter-laboratory variability in this performance test program was so high that the reported results could not be used to reliably discriminate among filters prepared to reflect 8-h exposures to respirable quartz concentrations of 25, 50 and 100 μg/m(3). Moreover, even in intra-laboratory performance, there was so much variability in the reported results that 2-fold variations in exposure concentrations could not be reliably distinguished. Part of the variability and underreporting may result from the sample preparation process. The results of this study suggest that current laboratory methods and practices cannot necessarily be depended on, with high confidence, to support proposed regulatory standards with reliable data.

  3. Validation of LIRIC aerosol concentration retrievals using airborne measurements during a biomass burning episode over Athens

    NASA Astrophysics Data System (ADS)

    Kokkalis, Panagiotis; Amiridis, Vassilis; Allan, James D.; Papayannis, Alexandros; Solomos, Stavros; Binietoglou, Ioannis; Bougiatioti, Aikaterini; Tsekeri, Alexandra; Nenes, Athanasios; Rosenberg, Philip D.; Marenco, Franco; Marinou, Eleni; Vasilescu, Jeni; Nicolae, Doina; Coe, Hugh; Bacak, Asan; Chaikovsky, Anatoli

    2017-01-01

    In this paper we validate the Lidar-Radiometer Inversion Code (LIRIC) retrievals of the aerosol concentration in the fine mode, using the airborne aerosol chemical composition dataset obtained over the Greater Athens Area (GAA) in Greece, during the ACEMED campaign. The study focuses on the 2nd of September 2011, when a long-range transported smoke layer was observed in the free troposphere over Greece, in the height range from 2 to 3 km. CIMEL sun-photometric measurements revealed high AOD ( 0.4 at 532 nm) and Ångström exponent values ( 1.7 at 440/870 nm), in agreement with coincident ground-based lidar observations. Airborne chemical composition measurements performed over the GAA, revealed increased CO volume concentration ( 110 ppbv), with 57% sulphate dominance in the PM1 fraction. For this case, we compare LIRIC retrievals of the aerosol concentration in the fine mode with the airborne Aerosol Mass Spectrometer (AMS) and Passive Cavity Aerosol Spectrometer Probe (PCASP) measurements. Our analysis shows that the remote sensing retrievals are in a good agreement with the measured airborne in-situ data from 2 to 4 km. The discrepancies observed between LIRIC and airborne measurements at the lower troposphere (below 2 km), could be explained by the spatial and temporal variability of the aerosol load within the area where the airborne data were averaged along with the different time windows of the retrievals.

  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. 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

  6. 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.

  7. Environmental determinants of polychlorinated biphenyl concentrations in residential carpet dust

    PubMed Central

    DellaValle, Curt T.; Wheeler, David C.; Deziel, Nicole C.; De Roos, Anneclaire J.; Cerhan, James R.; Cozen, Wendy; Severson, Richard K.; Flory, Abigail R.; Locke, Sarah J.; Colt, Joanne S.; Hartge, Patricia; Ward, Mary H.

    2014-01-01

    Polychlorinated biphenyls (PCBs), banned in the United Sates in the late 1970s, are still found in indoor and outdoor environments. Little is known about the determinants of PCB levels in homes. We measured concentrations of 5 PCB congeners (105, 138, 153, 170, 180) in carpet dust collected between 1998–2000 from 1,187 homes in four sites: Detroit, Iowa, Los Angeles, and Seattle. Home characteristics, occupational history, and demographic information were obtained by interview. We used a geographic information system to geocode addresses and determine distances to the nearest major road, freight route, and railroad, percentage of developed land, number of industrial facilities within 2 km of residences, and population density. Ordinal logistic regression was used to estimate the associations between the covariates of interest and the odds of PCB detection in each site separately. Total PCBs levels (all congeners < maximum practical quantitation limit [MPQL] vs. at least one congener ≥ MPQL to < median concentration vs. at least one congener >median concentration) were positively associated with either percentage of developed land (ORrange: 1.01-1.04 for each percentage increase) or population density (OR: 1.08 for every 1,000/mi2) in each site. The number of industrial facilities within 2 km of a home was associated with PCB concentrations; however, facility type and the direction of the association varied by site. Our findings suggest that outdoor sources of PCBs may be significant determinants of indoor concentrations. PMID:23952055

  8. Ambient airborne solids concentrations including volcanic ash at Hanford, Washington sampling sites subsequent to the Mount St. Helens eruption

    NASA Technical Reports Server (NTRS)

    Sehmel, G. A.

    1982-01-01

    Airborne solids concentrations were measured on a near daily basis at two Hanford, Washington sites after the eruption of Mount St. Helens on May 18, 1980. These sites are about 211 km east of Mount St. Helens. Collected airborne solids included resuspended volcanic ash plus normal ambient solids. Average airborne solids concentrations were greater at the Hanford meteorological station sampling site which is 24 km northwest of the Horn Rapids dam sampling site. These increased concentrations reflect the sampling site proximity to greater ash fallout depths. Both sites are in low ash fallout areas although the Hanford meteorological station site is closer to the greater ash fallout areas. Airborne solids concentrations were decreased by rain, but airborne solids concentrations rapidly increased as surfaces dried. Airborne concentrations tended to become nearly the same at both sampling sites only for July 12 and 13.

  9. Quantitative analysis on windblown dust concentrations of PM10 (PM2.5) during dust events in Mongolia

    NASA Astrophysics Data System (ADS)

    Jugder, Dulam; Shinoda, Masato; Kimura, Reiji; Batbold, Altangerel; Amarjargal, Danzansambuu

    2014-09-01

    Dust concentration, wind speed and visibility, measured at four sites in the Gobi Desert and at a site in the steppe zone of Mongolia over a period of 4.5 years (January 2009 to May 2013), have been analyzed for their relationships, their effects on visibility, and for an estimate of the threshold wind necessary for dust emission in the region. Based on quantitative analysis on measurements, we evaluated that dust emission concentrations of 41-61 (20-24) μg m-3 of PM10 (PM2.5) are as the criterion between normal and hazy atmospheric conditions. With the arrival of dust events, wind-borne soil particulate matter (PM10, PM2.5) that originates in the Gobi Desert is changed dramatically. PM10 (PM2.5) concentrations increase by at least double or by several tens of times during severe dust events in comparison with the normal atmospheric condition. Ratio (PM2.5/PM10) between monthly means of PM10 and PM2.5 concentrations showed that anthropogenic particles were dominant in the ambient air of province centers in cool months (November to February). Threshold values of the onset of dust events were determined for PM10 (PM2.5) concentrations. According to the definition of dust storms, dust concentrations of PM10 corresponding to visibility of 1 km or less were determined at sites in the Gobi Desert and the steppe region. The threshold wind speeds during days with dust events were estimated at four sites in the Gobi Desert and compared each other. The threshold wind was higher at Sainshand and its cause might be due to smaller silt and clay fractions of soil.

  10. Methods for reducing particle concentrations of Aspergillus fumigatus conidia and mouldy hay dust.

    PubMed

    Edwards, J H; Trotman, D M; Mason, O F

    1985-08-01

    The effectiveness of commercially available domestic air purifiers to reduce airborne Aspergillus fumigatus conidia and mouldy hay dust was investigated. It was found that the rate of particle clearance is a function of the volume of air passing through the purifiers but that the low throughflow of air makes their use of little value in clearing particles from a normal sized room. Vacuum cleaners were more effective than air purifiers because of their higher air throughput, so too were high volume fan systems in conjunction with simple filtration units. Ionizers had no effect but steam condensation was very efficient at clearing airborne particles.

  11. Concentrations of airborne endotoxin and microorganisms at a 10,000-cow open-freestall dairy.

    PubMed

    Dungan, R S; Leytem, A B; Bjorneberg, D L

    2011-10-01

    Confined animal production systems produce increased bioaerosol concentrations, which are a potential respiratory health risk to individuals on site and downwind. In this longitudinal study, airborne endotoxin and microorganisms were collected during the spring, summer, and fall at a large, open-freestall dairy in southern Idaho. Compared with the background ambient atmosphere, both endotoxin and culturable heterotrophic bacteria concentrations were up to several-hundred-fold greater 50 m downwind from the facility, then decreased to near background concentrations at 200 m. However, downwind fungi concentrations were not increased above background concentrations. At 50 m downwind, the average inhalable endotoxin concentration ranged from 5 to 4,243 endotoxin units per m⁻³, whereas bacteria concentrations ranged from 10² to 10⁴ cfu per m⁻³ of air. Although the bioaerosol concentrations did not follow a seasonal trend, they did significantly correlate with meteorological factors. Increasing temperature was found to be positively correlated with increasing bacteria (r = 0.15, P < 0.05), fungi (r = 0.14, P < 0.05), and inhalable endotoxin (r = 0.32, P < 0.001) concentrations, whereas an inverse relationship occurred between the concentration and solar radiation. The airborne concentrations at 50 m were also found to be greatest at night, which can likely be attributed to changes in animal activity and wind speed and reduced exposure of the airborne microorganisms to UV radiation.

  12. Concentration and size distribution of total airborne microbes in hazy and foggy weather.

    PubMed

    Dong, Lijie; Qi, Jianhua; Shao, Congcong; Zhong, Xi; Gao, Dongmei; Cao, Wanwan; Gao, Jiawei; Bai, Ran; Long, Gaoyuan; Chu, Congcong

    2016-01-15

    Atmospheric bioaerosol particles were collected using a bioaerosol sampler from Oct. 2013 to Aug. 2014 in the coastal region of Qingdao. The total microbes were measured using an epifluorescence microscope after staining with DAPI (4',6-diamidino-2-phenylindole). The concentration of total airborne microbes showed seasonal variation, with the highest value in winter and the lowest in summer. The mean concentration of total microbes was 6.55 × 10(5)Cells/m(3) on non-hazy days. The total microbe concentration increased to 7.09 × 10(5) and 9.00 × 10(5)Cells/m(3) on hazy and foggy days, respectively. The particle sizes of the total microbes presented a bimodal distribution on sunny days, with one peak at 1.1-2.1 μm and another at 4.7-7.0 μm. The size distribution of total microbes showed an increase in the fine fraction on hazy days and an increase in the coarse fraction on foggy days. However, the size distribution became unimodal during a heating period. Spearman correlation analysis showed that temperature and O3 had a significant negative correlation with the airborne microbe concentration, while PM2.5, SO2, NO2, CO and the air quality index (AQI) had significant positive correlations with the airborne microbe concentration during hazy days. The increased number of airborne microbes will affect the air quality on hazy days.

  13. Cow allergen (Bos d2) and endotoxin concentrations are higher in the settled dust of homes proximate to industrial-scale dairy operations

    PubMed Central

    Williams, D' Ann L; McCormack, Meredith C; Matsui, Elizabeth C; Diette, Gregory B; McKenzie, Shawn E; Geyh, Alison S; Breysse, Patrick N

    2016-01-01

    Airborne contaminants produced by industrial agricultural facilities contain chemical and biological compounds that can impact the health of residents living in close proximity. Settled dust can be a reservoir for these contaminants and can influence long-term exposures. In this study, we sampled the indoor- and outdoor-settled dust from 40 homes that varied in proximity to industrial-scale dairies (ISD; industrial-scale dairy, a term used in this paper to describe a large dairy farm and adjacent waste sprayfields, concentrated animal feeding operation or animal feeding operation, that uses industrial processes) in the Yakima Valley, Washington. We analyzed settled dust samples for cow allergen (Bos d2, a cow allergen associated with dander, hair, sweat and urine, it is a member of the lipocalin family of allergens associated with mammals), mouse allergen (Mus m1; major mouse allergen, a mouse urinary allergen, in the lipocalin family), dust mite allergens (Der p1 (Dermatophagoides pteronissinus 1) and Der f1 (Dermatophagoides farinae 1)), and endotoxin (a component of the cell walls of gram negative bacteria, lipopolysaccharide, which can be found in air and dust and can produce a strong inflammatory response). A concentration gradient was observed for Bos d2 and endotoxin measured in outdoor-settled dust samples based on proximity to ISD. Indoor-settled dust concentrations of Bos d2 and endotoxin were also highest in proximal homes. While the associated health effects of exposure to cow allergen in settled dust is unknown, endotoxin at concentrations observed in these proximal homes (100 EU/mg) has been associated with increased negative respiratory health effects. These findings document that biological contaminants emitted from ISDs are elevated in indoor- and outdoor-settled dust samples at homes close to these facilities and extend to as much as three miles (4.8 km) away. PMID:25138294

  14. 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

  15. A study of local electrostatic filtration and main pre-filtration on airborne and surface dust levels in air-conditioned office premises.

    PubMed

    Croxford, B; Tham, K W; Young, A; Oreszczyn, T; Wyon, D

    2000-09-01

    The impact of electrostatic precipitation as a useful form of particulate filtration in the breathing zone is investigated in an intervention study in an air-conditioned commercial office in central London. Surface dust deposition and airborne dust levels are measured in the open plan zones of two floors--a control floor and a floor where the intervention is effected. The intervention consists of a sequence of weekly scenarios where the main pre-filters of the air-handling unit are switched between new and old filters, and where the electrostatic filters, located as uniformly as practicable on the open plan areas, are switched on or off. This 2 x 2 set of interventions is repeated over 4 cycles. It was found that the breathing zone filtration (BZF) by electrostatic precipitators reduces airborne dust significantly and appears to be more efficient in reducing smaller sized particles. No significant effect of BZF filters in reducing surface dust deposition was detected.

  16. Airborne concentrations of organophosphorus pesticides in Korean pesticide manufacturing/formulation workplaces.

    PubMed

    Han, Don-Hee

    2011-01-01

    Pesticide manufacturing/formulation workers rather than farmers or applicators or people living with them are primarily exposed to organophosphorus pesticides (OPs). However, airborne concentrations in the workplace have rarely been determined. A total of 121 air samples (personal or area sampling) were collected at 4 factories where chlorpyrifos, EPN, parathion, and phorate, were manufactured/formulated from March through July, 2007-2008. Samples were collected by the National Institute for Occupational Safety and Health (NIOSH) method and were analyzed by GC-MS. The geometric mean (GM) level of airborne chlorpyrifos was 0.17 mg/m(3), 85% Korean Occupational Exposure Limit (KOEL) of 0.2 mg/m(3), and at 95% confidence, airborne concentrations exceeded the KOEL 58.8% of the time or less, indicating that this concentration level was unacceptable according to exposure assessment using a LogNorm2(®). However, compared with levels of TLV and/or PEL and/or WEL, the GM concentration levels of other OPs were remarkably low (range, 0.1-15.0%) and that these levels of concentrations to the other OPs were acceptable. The levels of airborne concentrations of OPs depended on isolation of the process; in other words, the levels depended on the extent to which the process was automated. The reason that the airborne concentration levels, except for those of chlorpyrifos, were very much lower than expected may be attributable to the fact that there was not exposed to 100% toxic active ingredients in pesticide formulation workplaces because of the use of supplemental agents or additives to produce complete pesticides. This study is limited since there were seldom or neither any data of previous studies to be compared with the study results nor dermal exposure data. The results were used to revise KOELs for OPs in 2010.

  17. On the dust-equivalent series resistance of a photovoltaic concentrator

    NASA Astrophysics Data System (ADS)

    Zakzouk, A. K. M.

    1984-02-01

    A new concept for treating the effects of dust on the electrical performance of photovoltaic concentrators is presented in the paper. The dust concentration in the atmospheric air around the concentrator is measured continuously during the test period. The rate of dust accumulation on the concentrator surface is determined. The concentrator performance degradation, as a result of dust accumulation, is related to the amount of dust accumulated per unit area of the collector surface (in g/sq m) rather than the exposure time. It has been shown that major reductions in the short-circuit current and the efficiency are observed for dust accumulations up to 5.4 g/sq m. The accumulation of dust on the photovoltaic concentrator causes a successively larger 'rounding' of the I/V characteristic at constant incident direct normal radiation intensity and constant cell temperature. This effect is equivalent to an increase in the internal series resistance of the concentrator. This dust-equivalent series resistance increases with increasing dust accumulation.

  18. AIRBORNE ASBESTOS CONCENTRATIONS DURING BUFFING, BURNISHING, AND STRIPPING OF RESILIENT FLOOR TILE

    EPA Science Inventory

    The study was conducted to evaluate airborne asbestos concentrations during low-speed spray-buffing, ultra high-speed burnishing, and wet-stripping of asbestos-containing resilient floor tile under pre-existing and prepared levels of floor care maintenance. Low-speed spray-buffin...

  19. Concentrations of airborne endotoxin and microorganisms at a 10,000 cow open-freestall dairy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confined animal production systems produce elevated bioaerosol concentrations, which are a potential respiratory health risk to individuals on site and downwind. In this study, airborne endotoxin and microorganisms were collected during the spring, summer, and fall at a large open-freestall dairy i...

  20. Airborne asbestos concentration from brake changing does not exceed permissible exposure limit.

    PubMed

    Blake, Charles L; Van Orden, Drew R; Banasik, Marek; Harbison, Raymond D

    2003-08-01

    The use in the past, and to a lesser extent today, of chrysotile asbestos in automobile brake systems causes health concerns among professional mechanics. Therefore, we conducted four separate tests in order to evaluate an auto mechanic's exposure to airborne asbestos fibers while performing routine brake maintenance. Four nearly identical automobiles from 1960s having four wheel drum brakes were used. Each automobile was fitted with new replacement asbestos-containing brake shoes and then driven over a predetermined public road course for about 2253 km. Then, each car was separately brought into a repair facility; the brakes removed and replaced with new asbestos-containing shoes. The test conditions, methods, and tools were as commonly used during the 1960s. The mechanic was experienced in brake maintenance, having worked in the automobile repair profession beginning in the 1960s. Effects of three independent variables, e.g., filing, sanding, and arc grinding of the replacement brake shoe elements, were tested. Personal and area air samples were collected and analyzed for the presence of fibers, asbestos fibers, total dust, and respirable dust. The results indicated a presence in the air of only chrysotile asbestos and an absence of other types of asbestos. Airborne chrysotile fiber exposures for each test remained below currently applicable limit of 0.1 fiber/ml (eight-hour time-weighted average).

  1. 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.

  2. A method to quantify infectious airborne pathogens at concentrations below the threshold of quantification by culture.

    PubMed

    Cutler, Timothy D; Wang, Chong; Hoff, Steven J; Zimmerman, Jeffrey J

    2013-04-01

    In aerobiology, dose-response studies are used to estimate the risk of infection to a susceptible host presented by exposure to a specific dose of an airborne pathogen. In the research setting, host- and pathogen-specific factors that affect the dose-response continuum can be accounted for by experimental design, but the requirement to precisely determine the dose of infectious pathogen to which the host was exposed is often challenging. By definition, quantification of viable airborne pathogens is based on the culture of micro-organisms, but some airborne pathogens are transmissible at concentrations below the threshold of quantification by culture. In this paper we present an approach to the calculation of exposure dose at microbiologically unquantifiable levels using an application of the "continuous-stirred tank reactor (CSTR) model" and the validation of this approach using rhodamine B dye as a surrogate for aerosolized microbial pathogens in a dynamic aerosol toroid (DAT).

  3. Spacecraft maximum allowable concentrations for selected airborne contaminants, volume 1

    NASA Technical Reports Server (NTRS)

    1994-01-01

    As part of its efforts to promote safe conditions aboard spacecraft, NASA requested the National Research Council (NRC) to develop guidelines for establishing spacecraft maximum allowable concentrations (SMAC's) for contaminants, and to review SMAC's for various spacecraft contaminants to determine whether NASA's recommended exposure limits are consistent with the guidelines recommended by the subcommittee. In response to NASA's request, the NRC organized the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants within the Committee on Toxicology (COT). In the first phase of its work, the subcommittee developed the criteria and methods for preparing SMAC's for spacecraft contaminants. The subcommittee's report, entitled Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants, was published in 1992. The executive summary of that report is reprinted as Appendix A of this volume. In the second phase of the study, the Subcommittee on Spacecraft Maximum Allowable Concentrations reviewed reports prepared by NASA scientists and contractors recommending SMAC's for 35 spacecraft contaminants. The subcommittee sought to determine whether the SMAC reports were consistent with the 1992 guidelines. Appendix B of this volume contains the first 11 SMAC reports that have been reviewed for their application of the guidelines developed in the first phase of this activity and approved by the subcommittee.

  4. Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants. Volume 5

    NASA Technical Reports Server (NTRS)

    2008-01-01

    To protect space crews from air contaminants, NASA requested that the National Research Council (NRC) provide guidance for developing spacecraft maximum allowable concentrations (SMACs) and review NASA's development of exposure guidelines for specific chemicals. The NRC convened the Committee on Spacecraft Exposure Guidelines to address this task. The committee published Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants (NRC 1992). The reason for the review of chemicals in Volume 5 is that many of them have not been examined for more than 10 years, and new research necessitates examining the documents to ensure that they reflect current knowledge. New knowledge can be in the form of toxicologic data or in the application of new approaches for analysis of available data. In addition, because NASA anticipates longer space missions beyond low Earth orbit, SMACs for 1,000-d exposures have also been developed.

  5. Observations of Saharan dust microphysical and optical properties from the Eastern Atlantic during NAMMA airborne field campaign

    NASA Astrophysics Data System (ADS)

    Chen, G.; Ziemba, L. D.; Chu, D. A.; Thornhill, K. L.; Schuster, G. L.; Winstead, E. L.; Diskin, G. S.; Ferrare, R. A.; Burton, S. P.; Ismail, S.; Kooi, S. A.; Omar, A. H.; Slusher, D. L.; Kleb, M. M.; Reid, J. S.; Twohy, C. H.; Zhang, H.; Anderson, B. E.

    2011-01-01

    As part of the international project entitled "African Monsoon Multidisciplinary Analysis (AMMA)", NAMMA (NASA AMMA) aimed to gain a better understanding of the relationship between the African Easterly Waves (AEWs), the Sahara Air Layer (SAL), and tropical cyclogenesis. The NAMMA airborne field campaign was based out of the Cape Verde Islands during the peak of the hurricane season, i.e., August and September 2006. Multiple Sahara dust layers were sampled during 62 encounters in the eastern portion of the hurricane main development region, covering both the eastern North Atlantic Ocean and the western Saharan desert (i.e., 5-22° N and 10-35° W). The centers of these layers were located at altitudes between 1.5 and 3.3 km and the layer thickness ranged from 0.5 to 3 km. Detailed dust microphysical and optical properties were characterized using a suite of in-situ instruments aboard the NASA DC-8 that included a particle counter, an Ultra-High Sensitivity Aerosol Spectrometer, an Aerodynamic Particle Sizer, a nephelometer, and a Particle Soot Absorption Photometer. The NAAMA sampling inlet has a size cut (i.e., 50% transmission efficiency size) of approximately 4 μm in diameter for dust particles, which limits the representativeness of the NAMMA observational findings. The NAMMA dust observations showed relatively low particle number densities, ranging from 268 to 461 cm-3, but highly elevated volume density with an average at 45 μm3 cm-3. NAMMA dust particle size distributions can be well represented by tri-modal lognormal regressions. The estimated volume median diameter (VMD) is averaged at 2.1 μm with a small range of variation regardless of the vertical and geographical sampling locations. The Ångström Exponent assessments exhibited strong wavelength dependence for absorption but a weak one for scattering. The single scattering albedo was estimated at 0.97 ± 0.02. The imaginary part of the refractive index for Sahara dust was estimated at 0.0022, with a

  6. [Effect of low concentration of asbestos-containing dust].

    PubMed

    Kogan, F M; Kashanskiĭ, S V; Plotko, E G; Berzin, S A; Bogdanov, G B

    1993-01-01

    Dust, particularly fibrous, in atmosphere of Asbest town was characterized. Pulmonary cancer mortality in Asbest town and towns of nearby area were compared and no significant difference was found. Overall pulmonary cancer mortality was higher in the region than in Asbest. Obtained data served as a basis for discussion on the action threshold of asbestos-containing dust. MAC for asbestos fibers in atmosphere is reported to be 0.06 respirable fibers per ml.

  7. Total dust, respirable dust, and microflora toxin concentrations in Colorado corn storage facilities.

    PubMed

    Todd, Brit E; Buchan, Roy M

    2002-06-01

    To aid in the process of characterizing corn dust exposures on farms and in elevators in northeastern Colorado, several parameters were examined. Total dust and respirable dust samples were collected and evaluated. Potentially dangerous dust components evaluated were respirable silica, endotoxin, and mycotoxin levels. Many of the total dust samples (58%) would have exceeded 8-hour time-weighted average (TWA) had sampling been conducted for 8 hours; on farms the operation takes between two and four hours. The same statement may be made for respirable dust samples collected for this project. Nearly 33 percent of the respirable dust samples collected would have exceeded the Occupational Safety and Health Administration (OSHA) TWA had sampling been conducted over an 8-hour period. Respirable silica standards were exceeded at 25 percent of the sampling locations. Presence of mycotoxins at all sites was confirmed by the use of ELISA kits. The most significant finding of this study was high levels of endotoxin at several of the sampling sites. Eighty-five percent of the sampling locations had endotoxin levels above 500 EU/m3. One location, Farm 4, had endotoxin levels of above 1.7 million EU/m3.

  8. Concentrations of airborne pollen grains in Sivrihisar (Eskisehir), Turkey.

    PubMed

    Erkara, Ismuhan Potoglu

    2008-03-01

    Pollen grains in the atmosphere of Sivrihisar were studied for a continuous period of 2 years (1 January 2005-31 December 2006) using a Durham sampler. During this period, pollen grains belonging to 41 taxa were recorded, 24 of which belonged to arboreal plants and 17 to non-arboreal. From these, 23,219 were identified in 2005 and 34,154 in 2006. Of the total pollen grains, 90.46% were arboreal, 9.43% non-arboreal, and 0.1% unidentifiable. The majority of the investigated allergic pollen grains were from Pinaceae, Cupressaceae, Fraxinus spp., Cedrus spp., Artemisia spp., Poaceae, Chenopodiaceae/Amaranthaceae, Populus spp., Quercus spp., Urticaceae and Asteraceae, respectively. Pollen concentrations reached their highest levels in May. This information was then established into a calendar form according to the pollens determined in 2005-2006, in terms of annual, monthly and weekly numbers of taxa fall per cm2. A comparison between the results and the meteorological factors revealed a close relationship between pollen concentrations in the air and meteorological conditions. An increase in pollination was also linked to increasing temperatures and the wind. It was therefore concluded that high temperatures and relative humidity were also effective in increasing the number of pollens in the air.

  9. Determination of coal dust in airborne particulate materials by automated optical microscopy

    SciTech Connect

    McQuaker, N.R.; Sandberg, D.K.

    1984-11-01

    An automated optical technique for the determination of coal in airborne particulate materials is described. The technique may be used over the interval 1-5% (wt) coal when the sample is uniformly deposited as a monolayer on a cellulose acetate filter. The analytical precision is found to be acceptable. The accuracy for reference samples is shown to be either +/- 0.5% (by weight) or +/- 10% over the analytical range. The application of the method to authentic samples of airborne particulate materials is also discussed.

  10. Influence of dust-particle concentration on gas-discharge plasma

    SciTech Connect

    Sukhinin, G. I.; Fedoseev, A. V.

    2010-01-15

    A self-consistent kinetic model of a low-pressure dc glow discharge with dust particles based on Boltzmann equation for the electron energy distribution function is presented. The ions and electrons production in ionizing processes as well as their recombination on the dust-particle surface and on the discharge tube wall were taken into account. The influence of dust-particle concentration N{sub d} on gas discharge and dust particles parameters was investigated. It is shown that the increase of N{sub d} leads to the increase of an averaged electric field and ion density, and to the decrease of a dust-particle charge and electron density in the dusty cloud. The results were obtained in a wide region of different discharge and dusty plasma parameters: dust particles density 10{sup 2}-10{sup 8} cm{sup -3}, discharge current density 10{sup -1}-10{sup 1} mA/cm{sup 2}, and dust particles radius 1, 2, and 5 mum. The scaling laws for dust-particle surface potential and electric filed dependencies on dust-particle density, particle radius and discharge currents were revealed. It is shown that the absorption of electrons and ions on the dust particles surface does not lead to the electron energy distribution function depletion due to a self-consistent adjustment of dust particles and discharge parameters.

  11. Influence of dust-particle concentration on gas-discharge plasma.

    PubMed

    Sukhinin, G I; Fedoseev, A V

    2010-01-01

    A self-consistent kinetic model of a low-pressure dc glow discharge with dust particles based on Boltzmann equation for the electron energy distribution function is presented. The ions and electrons production in ionizing processes as well as their recombination on the dust-particle surface and on the discharge tube wall were taken into account. The influence of dust-particle concentration N(d) on gas discharge and dust particles parameters was investigated. It is shown that the increase of N(d) leads to the increase of an averaged electric field and ion density, and to the decrease of a dust-particle charge and electron density in the dusty cloud. The results were obtained in a wide region of different discharge and dusty plasma parameters: dust particles density 10(2)-10(8) cm(-3), discharge current density 10(-1)-10(1) mA/cm(2), and dust particles radius 1, 2, and 5 microm. The scaling laws for dust-particle surface potential and electric filed dependencies on dust-particle density, particle radius and discharge currents were revealed. It is shown that the absorption of electrons and ions on the dust particles surface does not lead to the electron energy distribution function depletion due to a self-consistent adjustment of dust particles and discharge parameters.

  12. Indoor and outdoor measurements of vertical concentration profiles of airborne particulate matter.

    PubMed

    Micallef, A; Deuchar, C N; Colls, J J

    1998-05-04

    Vertical concentration profiles of various particle size ranges of airborne particulate matter were measured from ground level up to 3 m, in outdoor and indoor environments. Indoor measurements were carried out in an electronics workshop, while two outdoor environments were chosen: a street canyon cutting across a town and an open field situated in a semi-rural environment. The novel measurement technique employed in this experimental work, which can also be used to determine vertical concentration gradients of pollutants other than airborne particles in different environments, is given particular attention. Analyses of the collected data for the environments considered are presented and some conclusions and plausible explanations of the profiles are discussed. The workshop and street canyon environments exhibited larger concentrations and vertical concentration gradients as compared to the sports field. This indicates that people breathing at different heights are subjected to different concentrations of airborne particulate matter, which has implications for sitting air pollution monitors intended for protection of public health and estimation of human exposure.

  13. Concentration and characterization of airborne particles in Tehran's subway system.

    PubMed

    Kamani, Hosein; Hoseini, Mohammad; Seyedsalehi, Mahdi; Mahdavi, Yousef; Jaafari, Jalil; Safari, Gholam Hosein

    2014-06-01

    Particulate matter is an important air pollutant, especially in closed environments like underground subway stations. In this study, a total of 13 elements were determined from PM10 and PM2.5 samples collected at two subway stations (Imam Khomeini and Sadeghiye) in Tehran's subway system. Sampling was conducted in April to August 2011 to measure PM concentrations in platform and adjacent outdoor air of the stations. In the Imam Khomeini station, the average concentrations of PM10 and PM2.5 were 94.4 ± 26.3 and 52.3 ± 16.5 μg m(-3) in the platform and 81.8 ± 22.2 and 35 ± 17.6 μg m(-3) in the outdoor air, respectively. In the Sadeghiye station, mean concentrations of PM10 and PM2.5 were 87.6 ± 23 and 41.3 ± 20.4 μg m(-3) in the platform and 73.9 ± 17.3 and 30 ± 15 μg m(-3), in the outdoor air, respectively. The relative contribution of elemental components in each particle fraction were accounted for 43% (PM10) and 47.7% (PM2.5) in platform of Imam Khomeini station and 15.9% (PM10) and 18.5% (PM2.5) in the outdoor air of this station. Also, at the Sadeghiye station, each fraction accounted for 31.6% (PM10) and 39.8% (PM2.5) in platform and was 11.7% (PM10) and 14.3% (PM2.5) in the outdoor. At the Imam Khomeini station, Fe was the predominant element to represent 32.4 and 36 % of the total mass of PM10 and PM2.5 in the platform and 11.5 and 13.3% in the outdoor, respectively. At the Sadeghiye station, this element represented 22.7 and 29.8% of total mass of PM10 and PM2.5 in the platform and 8.7 and 10.5% in the outdoor air, respectively. Other major crustal elements were 5.8% (PM10) and 5.3% (PM2.5) in the Imam Khomeini station platform and 2.3 and 2.4% in the outdoor air, respectively. The proportion of other minor elements was significantly lower, actually less than 7% in total samples, and V was the minor concentration in total mass of PM10 and PM2.5 in both platform stations.

  14. Airborne Sun photometer measurements of aerosol optical depth and columnar water vapor during the Puerto Rico Dust Experiment and comparison with land, aircraft, and satellite measurements

    NASA Astrophysics Data System (ADS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey S.; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Smirnov, Alexander; Dubovik, Oleg; Welton, Ellsworth J.; Campbell, James R.; Wang, Jun; Christopher, Sundar A.

    2003-10-01

    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 above sea level (asl) reproduce the vertical structure measured by coincident aircraft in situ measurements of total aerosol number concentration. AATS-6 extinction retrievals also agree with corresponding values derived from ground-based lidar measurements for altitudes above the trade inversion. The spectral behavior of AOD within specific layers beneath the top of the aircraft profile is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt, with mean Ångström wavelength exponents of ˜0.20. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in situ measurements agree to within ˜4% (0.13 g/cm2). 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 0.004-0.030 with coincident data obtained with an AERONET Sun/sky radiometer located on Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by ˜21%. AATS-6 AOD values measured during low-altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the Moderate-Resolution Imaging Spectroradiometer (MODIS), Total Ozone Mapping Spectrometer (TOMS), and GOES 8 Imager satellite sensors, with mixed results.

  15. The Martian polar cap - Radiative effects of ozone, clouds, and airborne dust

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1990-01-01

    The solar and thermal flux striking the polar cap of Mars is computed for various ozone, dust, and cloud abundances and for three solar zenith angles. Ozone does not significantly affect the total energy budget of the polar cap. Hence the observed hemispherical asymmetry in ozone abundance causes only an insignificant hemispherical asymmetry in the polar caps. Vertical optical depths of dust and cloud ranging from zero to 1 cause little change in the total flux absorbed by the polar cap near its edge but increase the absorbed flux significantly as one travels poleward. Hemispherical asymmetries in dust abundance, cloud cover, and surface pressure combine to cause a significant hemispherical asymmetry in the total flux absorbed by the residual polar caps, which helps to explain the dichotomy in the residual polar caps on Mars. Other processes which affect the energy budget of the polar cap are proposed and reviewed, particularly with respect to their interaction with the radiative effects of clouds and dust.

  16. Observations of Saharan dust microphysical and optical properties from the Eastern Atlantic during NAMMA airborne field campaign

    NASA Astrophysics Data System (ADS)

    Chen, G.; Ziemba, L. D.; Chu, D. A.; Thornhill, K. L.; Schuster, G. L.; Winstead, E. L.; Diskin, G. S.; Ferrare, R. A.; Burton, S. P.; Ismail, S.; Kooi, S. A.; Omar, A. H.; Slusher, D. L.; Kleb, M. M.; Reid, J. S.; Twohy, C. H.; Zhang, H.; Anderson, B. E.

    2010-05-01

    As part of the international project entitled "African Monsoon Multidisciplinary Analysis (AMMA)", NAMMA (NASA AMMA) aimed to gain a better understanding of the relationship between the African Easterly Waves (AEWs), the Sahara Air Layer (SAL), and tropical cyclogenesis. The NAMMA airborne field campaign was based out of the Cape Verde Islands during the peak of the hurricane season, i.e., August and September 2006. Multiple Sahara dust layers were sampled during 62 encounters in the eastern portion of the hurricane main development region, covering both the eastern North Atlantic Ocean and the western Saharan desert (i.e., 5-22° N and 10-35° W). The centers of these layers were located at altitudes between 1.5 and 3.3 km and the layer thickness ranged from 0.5 to 3 km. Detailed dust microphysical and optical properties were characterized using a suite of in situ instruments aboard the NASA DC-8 that included a particle counter, an Ultra-High Sensitivity Aerosol Spectrometer, an Aerodynamic Particle Sizer, nephelometer, and Particle Soot Absorption Photometer. The NAMMA dust observations showed relatively low particle number densities, ranging from 268 to 461 cm-3, but highly elevated volume density with an average at 45 μm3 cm-3. NAMMA dust particle size distributions were well represented by tri-modal lognormal regressions. The estimated volume median diameter (VMD) is averaged at 2.1 μm with a small range of variation regardless of the vertical and geographical sampling locations. The absorption coefficient measurements exhibited a strong wavelength dependence for absorption but a weak one for scattering. The single scattering albedo was estimated at 0.97±0.02. Closure analyses showed that observed scattering and absorption coefficients are highly correlated with those calculated from spherical Mie-Theory and observed dust particle size distributions. The imaginary part of the refractive index for Sahara dust was estimated at 0.0022, with a range from 0

  17. 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

  18. Dust deposition and ambient PM10 concentration in northwest China: spatial and temporal variability

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Xiao; Sharratt, Brenton; Chen, Xi; Wang, Zi-Fa; Liu, Lian-You; Guo, Yu-Hong; Li, Jie; Chen, Huan-Sheng; Yang, Wen-Yi

    2017-02-01

    Eolian dust transport and deposition are important geophysical processes which influence global bio-geochemical cycles. Currently, reliable deposition data are scarce in central and east Asia. Located at the boundary of central and east Asia, Xinjiang Province of northwestern China has long played a strategic role in cultural and economic trade between Asia and Europe. In this paper, we investigated the spatial distribution and temporal variation in dust deposition and ambient PM10 (particulate matter in aerodynamic diameter ≤ 10 µm) concentration from 2000 to 2013 in Xinjiang Province. This variation was assessed using environmental monitoring records from 14 stations in the province. Over the 14 years, annual average dust deposition across stations in the province ranged from 255.7 to 421.4 t km-2. Annual dust deposition was greater in southern Xinjiang (663.6 t km-2) than northern (147.8 t km-2) and eastern Xinjiang (194.9 t km-2). Annual average PM10 concentration across stations in the province varied from 100 to 196 µg m-3 and was 70, 115 and 239 µg m-3 in northern, eastern and southern Xinjiang, respectively. The highest annual dust deposition (1394.1 t km-2) and ambient PM10 concentration (352 µg m-3) were observed in Hotan, which is located in southern Xinjiang and at the southern boundary of the Taklamakan Desert. Dust deposition was more intense during the spring and summer than other seasons. PM10 was the main air pollutant that significantly influenced regional air quality. Annual average dust deposition increased logarithmically with ambient PM10 concentration (R2 ≥ 0.81). While the annual average dust storm frequency remained unchanged from 2000 to 2013, there was a positive relationship between dust storm days and dust deposition and PM10 concentration across stations. This study suggests that sand storms are a major factor affecting the temporal variability and spatial distribution of dust deposition in northwest China.

  19. Impacts of the East Asian Monsoon on springtime dust concentrations over China: IMPACTS OF MONSOON ON DUST

    SciTech Connect

    Lou, Sijia; Russell, Lynn M.; Yang, Yang; Xu, Li; Lamjiri, Maryam A.; DeFlorio, Michael J.; Miller, Arthur J.; Ghan, Steven J.; Liu, Ying; Singh, Balwinder

    2016-07-12

    We use 150 year preindustrial simulations of the Community Earth System Model to quantify the impacts of the East Asian Monsoon strength on interannual variations of springtime dust concentrations over China. The simulated interannual variations in March-April-May (MAM) dust column concentrations range between 20–40% and 10–60% over eastern and western China, respectively. The dust concentrations over eastern China correlate negatively with the East Asian Monsoon (EAM) index, which represents the strength of monsoon, with a regionally averaged correlation coefficient of 0.64. Relative to the strongest EAM years, MAMdust concentrations in the weakest EAM years are higher over China, with regional relative differences of 55.6%, 29.6%, and 13.9% in the run with emissions calculated interactively and of 33.8%, 10.3%, and 8.2% over eastern, central, and western China, respectively, in the run with prescribed emissions. Both interactive run and prescribed emission run show the similar pattern of climate change between the weakest and strongest EAM years. Strong anomalous northwesterly and westerly winds over the Gobi and Taklamakan deserts during the weakest EAM years result in larger transport fluxes, and thereby increase the dust concentrations over China. These differences in dust concentrations between the weakest and strongest EAM years (weakest-strongest) lead to the change in the net radiative forcing by up to 8 and 3Wm2 at the surface, compared to 2.4 and +1.2Wm2 at the top of the atmosphere over eastern and western China, respectively.

  20. Influence of the Latitudinal Temperature Gradient on Soil Dust Concentration and Deposition in Greenland

    NASA Technical Reports Server (NTRS)

    Tegen, Ina; Rind, David

    2000-01-01

    To investigate the effects of changes in the latitudinal temperature gradient and the global mean temperature on dust concentration in the Northern Hemisphere, experiments with the GISS GCM (Goddard Institute for Space Studies General Circulation Model) are performed. The dust concentration over Greenland is calculated from sources in central and eastern Asia, which are integrated on-line in the model. The results show that an increase in the latitudinal temperature gradient increases both the Asian dust source strength and the concentration over Greenland. The source increase is the result of increased surface winds, and to a minor extent, the increase in Greenland dust is also associated with increased northward transport. Cooling the climate in addition to this increased gradient leads to a decrease in precipitation scavenging, which helps produce a further (slight) increase in Greenland dust in this experiment. Reducing the latitudinal gradient reduces the surface wind and hence the dust source, with a subsequent reduction in Greenland dust concentrations. Warming the climate in addition to this reduced gradient leads to a further reduction in Greenland dust due to enhanced precipitation scavenging. These results can be used to evaluate the relationship of Greenland ice core temperature changes to changes in the latitudinal and global temperatures.

  1. Influence of the Latitudinal Temperature Gradient on Soil Dust Concentration and Deposition in Greenland

    NASA Technical Reports Server (NTRS)

    Tegen, Ina; Rind, David

    2000-01-01

    To investigate the effects of changes in the latitudinal temperature gradient and the global mean temperature on dust concentration in the Northern Hemisphere, experiments with the Goddard Institute for Space Studies General Circulation Model (GISS GCM) are performed. The dust concentration over Greenland is calculated from sources in central and eastern Asia, which are integrated on-line in the model. The results show that an increase in the latitudinal temperature gradient increases both the Asian dust source strength and the concentration over Greenland. The source increase is the result of increased surface winds, and to a minor extent, the increase in Greenland dust is also associated with increased northward transport. Cooling the climate in addition to this increased gradient leads to a decrease in precipitation scavenging, which helps produce a further (slight) increase in Greenland dust in this experiment. Reducing the latitudinal gradient reduces the surface wind and hence the dust source, with a subsequent reduction in Greenland dust concentrations. Warming the climate in addition to this reduced gradient leads to a further reduction in Greenland dust due to enhanced precipitation scavenging. These results can be used to evaluate the relationship of Greenland ice core temperature changes to changes in the latitudinal and global temperatures.

  2. Particle size and metals concentrations of dust from a paint manufacturing plant.

    PubMed

    Huang, Siew Lai; Yin, Chun-Yang; Yap, Siaw Yang

    2010-02-15

    In this study, the particle size distribution and concentration of metallic elements of solvent- and water-based paint dust from bulk dust collected from dust-collecting hoppers were determined. The mean particle size diameter over a 12-week sampling period was determined using a particle size analyzer. The metals composition and concentration of the dust were determined via acid digestion technique followed by concentration analysis using inductively coupled plasma. The volume weighted mean particle diameters were found to be 0.941+/-0.016 and 8.185+/-0.201 microm for solvent- and water-based paint dust, respectively. The mean concentrations of metals in solvent-based paint dust were found to be 100+/-20.00 microg/g (arsenic), 1550+/-550.00 microg/g (copper), 15,680+/-11,780.00 microg/g (lead) and 30,460+/-10,580.00 microg/g (zinc) while the mean concentrations of metals in water-based paint dust were found to be 20.65+/-6.11 microg/g (arsenic), 9.14+/-14.65 microg/g (copper), 57.46+/-22.42 microg/g (lead) and 1660+/-1260 microg/g (zinc). Both paint dust types could be considered as hazardous since almost all of the dust particles were smaller than 10 microm. Particular emphasis on containment of solvent-based paint dust particles should be given since it was shown that they were very fine in size (<1 microm) and had high lead and zinc concentrations.

  3. The evaluation and quantification of respirable coal and silica dust concentrations: a task-based approach.

    PubMed

    Grové, T; Van Dyk, T; Franken, A; Du Plessis, J

    2014-01-01

    Silicosis and coal worker's pneumoconiosis are serious occupational respiratory diseases associated with the coal mining industry and the inhalation of respirable dusts containing crystalline silica. The purpose of this study (funded by the Mine Health and Safety Council of South Africa) was to evaluate the individual contributions of underground coal mining tasks to the respirable dust and respirable silica dust concentrations in an underground section by sampling the respirable dust concentrations at the intake and return of each task. The identified tasks were continuous miner (CM) cutting, construction, transfer of coal, tipping, and roof bolting. The respirable dust-generating hierarchy of the tasks from highest to lowest was: transfer of coal > CM right cutting > CM left cutting > CM face cutting > construction > roof bolting > tipping; and for respirable silica dust: CM left cutting > construction > transfer of coal > CM right cutting. Personal exposure levels were determined by sampling the exposures of workers performing tasks in the section. Respirable dust concentrations and low concentrations of respirable silica dust were found at the intake air side of the section, indicating that air entering the section is already contaminated. The hierarchy for personal respirable dust exposures was as follows, from highest to lowest: CM operator > cable handler > miner > roof bolt operator > shuttle car operator, and for respirable silica dust: shuttle car operator > CM operator > cable handler > roof bolt operator > miner. Dust control methods to lower exposures should include revision of the position of workers with regard to the task performed, positioning of the tasks with regard to the CM cutting, and proper use of the line curtains to direct ventilation appropriately. The correct use of respiratory protection should also be encouraged.

  4. Device and method for accurately measuring concentrations of airborne transuranic isotopes

    DOEpatents

    McIsaac, C.V.; Killian, E.W.; Grafwallner, E.G.; Kynaston, R.L.; Johnson, L.O.; Randolph, P.D.

    1996-09-03

    An alpha continuous air monitor (CAM) with two silicon alpha detectors and three sample collection filters is described. This alpha CAM design provides continuous sampling and also measures the cumulative transuranic (TRU), i.e., plutonium and americium, activity on the filter, and thus provides a more accurate measurement of airborne TRU concentrations than can be accomplished using a single fixed sample collection filter and a single silicon alpha detector. 7 figs.

  5. Device and method for accurately measuring concentrations of airborne transuranic isotopes

    DOEpatents

    McIsaac, Charles V.; Killian, E. Wayne; Grafwallner, Ervin G.; Kynaston, Ronnie L.; Johnson, Larry O.; Randolph, Peter D.

    1996-01-01

    An alpha continuous air monitor (CAM) with two silicon alpha detectors and three sample collection filters is described. This alpha CAM design provides continuous sampling and also measures the cumulative transuranic (TRU), i.e., plutonium and americium, activity on the filter, and thus provides a more accurate measurement of airborne TRU concentrations than can be accomplished using a single fixed sample collection filter and a single silicon alpha detector.

  6. [The airborne 1,3-butadiene concentrations in rubber and plastic processing plants].

    PubMed

    Yoshida, Toshiaki; Tainaka, Hidetsugu; Matsunaga, Ichiro; Goto, Sumio

    2002-03-01

    Environment pollution by 1,3-butadiene had considerably increased in Japan. The main cause of the pollution is the automotive exhaust gas, and leaks from factories, smoking, and burning of rubber and plastic products are considered to be minor sources. The object of this study was to determine the contamination levels of airborne 1,3-butadiene in factories processing rubber and plastics containing 1,3-butadiene. The concentrations of airborne 1,3-butadiene were measured in 21 plants (10 rubber processing plants and 11 plastics processing plants) in Osaka. 1,3-Butadiene in air was collected for 10 minutes with a charcoal tube and a portable small pump adjusted to a 250 ml/min flow rate. In each plant, indoor air samples at five points and an outdoor air sample at one point outside the plant were collected. The samples were subjected to gas chromatography/mass spectrometry after thermal desorption from the charcoal. The concentrations of airborne 1,3-butadiene in the rubber processing plants and the plastics processing plants were 0.14-2.20 micrograms/m3 (geometric mean: 0.48 microgram/m3) and 0.23-4.51 micrograms/m3 (geometric mean: 0.80 microgram/m3), respectively. In all plants examined, indoor 1,3-butadiene concentrations were higher than the outdoor concentrations around the plants. Therefore, 1,3-butadiene was considered to arise from the processing of rubber or plastics, but the indoor 1,3-butadiene concentrations were much lower than the PEL-TWA (1 ppm = 2.21 mg/m3) of OSHA and the TLV-TWA (2 ppm) of ACGIH. The concentrations in the plants with closed room conditions without ventilation were higher than the concentrations in the other plants. It was suggested that ventilation affected the 1,3-butadiene concentration in the plants.

  7. Non-Seasonal Variation of Airborne Aspergillus Spore Concentration in a Hospital Building

    PubMed Central

    Oberle, Michael; Reichmuth, Markus; Laffer, Reto; Ottiger, Cornelia; Fankhauser, Hans; Bregenzer, Thomas

    2015-01-01

    Nosocomial fungal infections are gaining increased attention from infectiologists. An adequate investigation into the levels of airborne Aspergillus and other fungal spores in hospital settings, under normal conditions, is largely unknown. We monitored airborne spore contamination in a Swiss hospital building in order to establish a seasonally-dependent base-line level. Air was sampled using an impaction technique, twice weekly, at six different locations over one year. Specimens were seeded in duplicate on Sabouraud agar plates. Grown colonies were identified to genus levels. The airborne Aspergillus spore concentration was constantly low throughout the whole year, at a median level of 2 spores/m3 (inter-quartile range = IQR 1–4), and displayed no seasonal dependency. The median concentration of other fungal spores was higher and showed a distinct seasonal variability with the ambient temperature change during the different seasons: 82 spores/m3 (IQR 26–126) in summer and 9 spores/m3 (IQR 6–15) in winter. The spore concentration varied considerably between the six sampling sites in the building (10 to 26 spores/m3). This variability may explain the variability of study results in the literature. PMID:26516890

  8. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... particles (5 microns or less in diameter) per cubic foot of air sampled. (b) Before a drilling test is... breathing zone of the drill operators during the drilling of each test hole. Time consumed in changing...

  9. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... particles (5 microns or less in diameter) per cubic foot of air sampled. (b) Before a drilling test is... breathing zone of the drill operators during the drilling of each test hole. Time consumed in changing...

  10. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... particles (5 microns or less in diameter) per cubic foot of air sampled. (b) Before a drilling test is... breathing zone of the drill operators during the drilling of each test hole. Time consumed in changing...

  11. 30 CFR 33.32 - Determination of dust concentration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL... particles (5 microns or less in diameter) per cubic foot of air sampled. (b) Before a drilling test is... breathing zone of the drill operators during the drilling of each test hole. Time consumed in changing...

  12. 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... particles (5 microns or less in diameter) per cubic foot of air sampled. (b) Before a drilling test is... breathing zone of the drill operators during the drilling of each test hole. Time consumed in changing...

  13. Practical aspects of sampling for organic dusts and microorganisms.

    PubMed

    Morey, P R

    1990-01-01

    Air sampling for organic dusts and microorganisms was carried out in silos when moldy silage was discarded through the discharge chute. Concentrations of respirable dust and airborne viable microorganisms exceeded 20 mg/m3 and 1 x 10(9)/m3, respectively, when dry silage was removed from silos. Much lower concentrations of dust and microorganisms were present when wet silage was discarded. Impinger and filter cassette samplers were equally effective in collecting the hardy spores present in silage dusts.

  14. Determination of heavy metal concentrations in street dusts in Istanbul E-5 highway.

    PubMed

    Sezgin, Naim; Ozcan, H Kurtulus; Demir, Goksel; Nemlioglu, Semih; Bayat, Cuma

    2004-01-01

    Components and quantity of street dust are environmental pollution indicators especially in big cities. Street dust is generally composed of car exhaust gas originated particles and wind-transported particles. Heavy metals, which are found in street dust, such as Pb, Cu, Mn, Zn, Cd and Ni are significant for environmental pollution. According to the kind of vehicle in traffic, quantity and type of heavy metals vary in street dust. The use of leaded gasoline gives a boost to the importance of lead level especially in street dust even at the start of 21st century. These metals possess bioaccumulation property, and the possibility of the amount of these metals reaching a critical value and threatening human health increases the importance of this issue. In this study, street dusts have been collected from E-5 Highway from Topkapi to Avcilar regions that spans about 18 km in Istanbul, Turkey, and Pb, Cu, Mn, Zn, Cd and Ni concentrations have been detected in street dust. Twenty-two street dust samples were taken from a total of 22 different points at previously decided 14 main areas. Analyses were conducted using Leeds Public Analyst method. According to the results of this study, Pb, Cu and Zn concentrations in E-5 Highway between Topkapi and Avcilar region in Istanbul were higher than maximum concentration levels of these heavy metals in normal soil. This situation indicates that there is heavy metal pollution in the inspected area in E-5 Highway in Istanbul.

  15. Increase in dust storm related PM10 concentrations: A time series analysis of 2001-2015.

    PubMed

    Krasnov, Helena; Katra, Itzhak; Friger, Michael

    2016-06-01

    Over the last decades, changes in dust storms characteristics have been observed in different parts of the world. The changing frequency of dust storms in the southeastern Mediterranean has led to growing concern regarding atmospheric PM10 levels. A classic time series additive model was used in order to describe and evaluate the changes in PM10 concentrations during dust storm days in different cities in Israel, which is located at the margins of the global dust belt. The analysis revealed variations in the number of dust events and PM10 concentrations during 2001-2015. A significant increase in PM10 concentrations was identified since 2009 in the arid city of Beer Sheva, southern Israel. Average PM10 concentrations during dust days before 2009 were 406, 312, and 364 μg m(-3) (median 337, 269,302) for Beer Sheva, Rehovot (central Israel) and Modi'in (eastern Israel), respectively. After 2009 the average concentrations in these cities during dust storms were 536, 466, and 428 μg m(-3) (median 382, 335, 338), respectively. Regression analysis revealed associations between PM10 variations and seasonality, wind speed, as well as relative humidity. The trends and periodicity are stronger in the southern part of Israel, where higher PM10 concentrations are found. Since 2009 dust events became more extreme with much higher daily and hourly levels. The findings demonstrate that in the arid area variations of dust storms can be quantified easier through PM10 levels over a relatively short time scale of several years.

  16. Setting Spacecraft Maximum Allowable Concentrations for 1 hour or 24 hour contingency exposures to airborne chemicals

    NASA Technical Reports Server (NTRS)

    Garcia, Hector D.; Limero, Thomas F.; James, John T.

    1992-01-01

    Since the early years of the manned space program, NASA has developed and used exposure limits called Spacecraft Maximum Allowable Concentrations (SMACs) to help protect astronauts from airborne toxicants. Most of these SMACS are based on an exposure duration of 7 days, since this is the duration of a 'typical' mission. A set of 'contingency SMACs' is also being developed for scenarios involving brief (1-hour or 24- hour) exposures to relatively high levels of airborne toxicants from event-related 'contingency' releases of contaminants. The emergency nature of contingency exposures dictates the use of different criteria for setting exposure limits. The NASA JSC Toxicology Group recently began a program to document the rationales used to set new SMACs and plans to review the older, 7-day SMACs. In cooperation with the National Research Council's Committee on Toxicology, a standard procedure has been developed for researching, setting, and documenting SMAC values.

  17. Climate change effects on airborne pathogenic bioaerosol concentrations: a scenario analysis.

    PubMed

    van Leuken, J P G; Swart, A N; Droogers, P; van Pul, A; Heederik, D; Havelaar, A H

    2016-01-01

    The most recent IPCC report presented further scientific evidence for global climate change in the twenty-first century. Important secondary effects of climate change include those on water resource availability, agricultural yields, urban healthy living, biodiversity, ecosystems, food security, and public health. The aim of this explorative study was to determine the range of expected airborne pathogen concentrations during a single outbreak or release in a future climate compared to a historical climatic period (1981-2010). We used five climate scenarios for the periods 2016-2045 and 2036-2065 defined by the Royal Netherlands Meteorological Institute and two conversion tools to create hourly future meteorological data sets. We modelled season-averaged airborne pathogen concentrations by means of an atmospheric dispersion model and compared these data to historical (1981-2010) modelled concentrations. Our results showed that modelled concentrations were modified several percentage points on average as a result of climate change. On average, concentrations were reduced in four out of five scenarios. Wind speed and global radiation were of critical importance, which determine horizontal and vertical dilution. Modelled concentrations decreased on average, but large positive and negative hourly averaged effects were calculated (from -67 to +639 %). This explorative study shows that further research should include pathogen inactivation and more detailed probability functions on precipitation, snow, and large-scale circulation.

  18. Evaluation of SEVIRI Thermal Infra-Red data for airborne dust detection in an arid regions: the UAE case study

    NASA Astrophysics Data System (ADS)

    Gherboudj, I.; Parajuli, S. P.; Ghedira, H.

    2011-12-01

    Our interest in the study of the dust emission cycle over arid area results from the impacts that they have on the climate and atmospheric processes. Large dust concentration emitted even naturally or anthropogenic may reduce surface insolation by extinction of solar radiation. In addition, the knowledge of its spatio-temporal distribution is essential for monitoring several applications such as solar energy potential and health effect. Satellite-based remote sensing is an efficient tool to improve our understanding of the interaction of the desert dust and surrounding climate over regional and global scales with high frequency measurements. Thermal infrared (TIR) channels (3μm -15μm) of different satellites (MVIRI, AVHRR, MODIS, ADEOS-2/POLDER, TOMS, and MSG/SERIVI) were widely used for dust detection. Several dust detection and forecasting algorithms have been proposed based on these satellite data. However, the spatial and temporal variability of the physical characteristics of dust (concentrations, particle size distribution, location in the atmosphere, and chemical composition) has limited their estimations particularly with the dependence of the dust emission on the wind, soil water content, vegetation, and sediment availability. This study focuses on the analysis of the sensitivity of the MSG/SEVIRI TIR observation to dust generation, surface wind, soil moisture, and surface emissivity over the United Arab Emirates (UAE). SEVIRI observations were acquired in 2009 with temporal and spatial resolutions of 30 minutes and about 3km respectively. While the soil moisture is extracted from the AMSR-E data (1:30 AM and 1:30 PM) at spatial resolution of 25 km, the surface emissivity and Aerosol Optical Thickness were extracted from the MODIS products at spatial resolutions of 1 km and 100 km respectively. In coincidence with the satellites acquisitions, meteorological measurements were collected from seven met stations distributed over the selected study area (wind

  19. The effects of transported Asian dust on the composition and concentration of ambient fungi in Taiwan

    NASA Astrophysics Data System (ADS)

    Chao, H. Jasmine; Chan, Chang-Chuan; Rao, Carol Y.; Lee, Chung-Te; Chuang, Ying-Chih; Chiu, Yueh-Hsiu; Hsu, Hsiao-Hsien; Wu, Yi-Hua

    2012-03-01

    This study was conducted to evaluate the effects of transported Asian dust and other environmental parameters on the levels and compositions of ambient fungi in the atmosphere of northern Taiwan. We monitored Asian dust events in Taipei County, Taiwan from January 2003 to June 2004. We used duplicate Burkard portable air samplers to collect ambient fungi before, during, and after dust events. Six transported Asian dust events were monitored during the study period. Elevated concentrations of Aspergillus ( A. niger, specifically), Coelomycetes, Rhinocladiella, Sporothrix and Verticillium were noted ( p < 0.05) during Asian dust periods. Botryosporium and Trichothecium were only recovered during dust event days. Multiple regression analysis showed that fungal levels were positively associated with temperature, wind speed, rainfall, non-methane hydrocarbons and particulates with aerodynamic diameters ≤10 μm (PM10), and negatively correlated with relative humidity and ozone. Our results demonstrated that Asian dust events affected ambient fungal concentrations and compositions in northern Taiwan. Ambient fungi also had complex dynamics with air pollutants and meteorological factors. Future studies should explore the health impacts of ambient fungi during Asian dust events, adjusting for the synergistic/antagonistic effects of weather and air pollutants.

  20. A COMPACT CONCENTRATION OF LARGE GRAINS IN THE HD 142527 PROTOPLANETARY DUST TRAP

    SciTech Connect

    Casassus, Simon; Marino, Sebastian; Pérez, Sebastian; Christiaens, Valentin; Plas, Gerrit van der; Wright, Chris M.; Maddison, Sarah T.; Wootten, Al; Roman, Pablo; Moral, Victor; Pinilla, Paola; Wyatt, Mark; Ménard, Francois

    2015-10-20

    A pathway to the formation of planetesimals, and eventually giant planets, may occur in concentrations of dust grains trapped in pressure maxima. Dramatic crescent-shaped dust concentrations have been seen in recent radio images at submillimeter wavelengths. These disk asymmetries could represent the initial phases of planet formation in the dust trap scenario, provided that grain sizes are spatially segregated. A testable prediction of azimuthal dust trapping is that progressively larger grains should be more sharply confined and should follow a distribution that is markedly different from the gas. However, gas tracers such as {sup 12}CO and the infrared emission from small grains are both very optically thick where the submillimeter continuum originates, so previous observations have been unable to test the trapping predictions or to identify compact concentrations of larger grains required for planet formation by core accretion. Here we report multifrequency observations of HD 142527, from 34 to 700 GHz, that reveal a compact concentration of grains approaching centimeter sizes, with a few Earth masses, embedded in a large-scale crescent of smaller, submillimeter-sized particles. The emission peaks at wavelengths shorter than ∼1 mm are optically thick and trace the temperature structure resulting from shadows cast by the inner regions. Given this temperature structure, we infer that the largest dust grains are concentrated in the 34 GHz clump. We conclude that dust trapping is efficient enough for grains observable at centimeter wavelengths to lead to compact concentrations.

  1. A Compact Concentration of Large Grains in the HD 142527 Protoplanetary Dust Trap

    NASA Astrophysics Data System (ADS)

    Casassus, Simon; Wright, Chris M.; Marino, Sebastian; Maddison, Sarah T.; Wootten, Al; Roman, Pablo; Pérez, Sebastian; Pinilla, Paola; Wyatt, Mark; Moral, Victor; Ménard, Francois; Christiaens, Valentin; Cieza, Lucas; van der Plas, Gerrit

    2015-10-01

    A pathway to the formation of planetesimals, and eventually giant planets, may occur in concentrations of dust grains trapped in pressure maxima. Dramatic crescent-shaped dust concentrations have been seen in recent radio images at submillimeter wavelengths. These disk asymmetries could represent the initial phases of planet formation in the dust trap scenario, provided that grain sizes are spatially segregated. A testable prediction of azimuthal dust trapping is that progressively larger grains should be more sharply confined and should follow a distribution that is markedly different from the gas. However, gas tracers such as 12CO and the infrared emission from small grains are both very optically thick where the submillimeter continuum originates, so previous observations have been unable to test the trapping predictions or to identify compact concentrations of larger grains required for planet formation by core accretion. Here we report multifrequency observations of HD 142527, from 34 to 700 GHz, that reveal a compact concentration of grains approaching centimeter sizes, with a few Earth masses, embedded in a large-scale crescent of smaller, submillimeter-sized particles. The emission peaks at wavelengths shorter than ∼1 mm are optically thick and trace the temperature structure resulting from shadows cast by the inner regions. Given this temperature structure, we infer that the largest dust grains are concentrated in the 34 GHz clump. We conclude that dust trapping is efficient enough for grains observable at centimeter wavelengths to lead to compact concentrations.

  2. Elemental concentrations in deposited dust on leaves along an urbanization gradient.

    PubMed

    Simon, Edina; Baranyai, Edina; Braun, Mihály; Cserháti, Csaba; Fábián, István; Tóthmérész, Béla

    2014-08-15

    Environmental health is an essential component of the quality of life in modern societies. Monitoring of environmental quality and the assessment of environmental risks are often species based on the elemental concentration of deposited dust. Our result suggested that stomata size and distribution were the most important factors influencing the accumulation of air contaminants in leaves. We found that the leaves' surfaces of Acer negundo and Celtis occidentalis were covered by a large number of trichomes, and these species have proven to be suitable biomonitors for atmospheric pollution difficult; these can be overcome using bioindicator species. Leaves of Padus serotina, Acer campestre, A. negundo, Quercus robur and C. occidentalis were used to assess the amount of deposited dust and the concentration of contaminants in deposited dust in and around the city of Debrecen, Hungary. Samples were collected from an urban, suburban and rural area along an urbanization gradient. The concentrations of Ba, Cu, Fe, Mn, Ni, Pb, S, Sr and Zn were determined in deposited dust using ICP-OES. Scanning electron microscopy (SEM) was used to explore the morphological structure and dust absorbing capacity of leaves. We found significant differences in dust deposition among species, and dust deposition correlated with trichomes' density. Principal component analysis (PCA) also showed a total separation of tree.

  3. 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.

  4. Airborne concentrations of asbestos onboard maritime shipping vessels (1978-1992).

    PubMed

    Murbach, Dana M; Madl, Amy K; Unice, Ken M; Knutsen, Jeffrey S; Chapman, Pamela S; Brown, Jay L; Paustenbach, Dennis J

    2008-06-01

    The exposure of shipyard workers to asbestos has been frequently investigated during the installation, repair or removal of asbestos insulation. The same level of attention, however, has not been directed to asbestos exposure of maritime seamen or sailors. In this paper, we assemble and analyze historical industrial hygiene (IH) data quantifying airborne asbestos concentrations onboard maritime shipping vessels between 1978 and 1992. Air monitoring and bulk sampling data were compiled from 52 IH surveys conducted on 84 different vessels, including oil tankers and cargo vessels, that were docked and/or at sea, but these were not collected during times when there was interaction with asbestos-containing materials (ACMs). One thousand and eighteen area air samples, 20 personal air samples and 24 air samples of unknown origin were analyzed by phase contrast microscopy (PCM); 19 area samples and six samples of unknown origin were analyzed by transmission electron microscopy (TEM) and 13 area air samples were analyzed by scanning electron microscopy (SEM). In addition, 482 bulk samples were collected from suspected ACMs, including insulation, ceiling panels, floor tiles, valve packing and gaskets. Fifty-three percent of all PCM and 4% of all TEM samples were above their respective detection limits. The average airborne concentration for the PCM area samples (n = 1018) was 0.008 fibers per cubic centimeter (f cc(-1)) (95th percentile of 0.040 f cc(-1)). Air concentrations in the living and recreational areas of the vessels (e.g. crew quarters, common rooms) averaged 0.004 f cc(-1) (95th percentile of 0.014 f cc(-1)), while air concentrations in the engine rooms and machine shops averaged 0.010 f cc(-1) (95th percentile of 0.068 f cc(-1)). Airborne asbestos concentrations were also classified by vessel type (cargo, tanker or Great Lakes), transport status (docked or underway on active voyage) and confirmed presence of ACM. Approximately 1.3 and 0% of the 1018 area samples

  5. Ambient airborne-solids concentrations including volcanic ash at Hanford, Washington sampling sites subsequent to the Mount St. Helens eruption

    SciTech Connect

    Sehmel, G.A.

    1981-06-01

    A major eruption of Mount St. Helens, state of Washington, USA, occurred on May 18, 1980. The resulting volcanic ash plume was transported to the east. The Hanford area, northwest of Richland, Washington, was within the southern edge of the fallout plume. Airborne solid concentrations and airborne particle size distributions were measured at two sites in the Hanford area, a southern and northern site. During the initial sampling day (May 19), the average concentration for respirable particles, < 5.5-..mu..m diameter, was 1430-..mu..g/m/sup 3/ at the southern site; the total collection was 2610-..mu..g/m/sup 3/. The respirable content of the total airborne solids was 55%. At both sites average airborne solid concentrations decreased to 10- to 20-..mu..g/m/sup 3/ in December.

  6. Airborne endotoxin concentrations in indoor and outdoor particulate matter and their predictors in an urban city.

    PubMed

    Yoda, Y; Tamura, K; Shima, M

    2017-02-04

    Endotoxins are an important biological component of particulate matter and have been associated with adverse effects on human health. There have been some recent studies on airborne endotoxin concentrations. We collected fine (PM2.5 ) and coarse (PM10-2.5 ) particulate matter twice on weekdays and weekends each for 48 hour, inside and outside 55 homes in an urban city in Japan. Endotoxin concentrations in both fractions were measured using the kinetic Limulus Amebocyte Lysate assay. The relationships between endotoxin concentrations and household characteristics were evaluated for each fraction. Both indoor and outdoor endotoxin concentrations were higher in PM2.5 than in PM10-2.5 . In both PM2.5 and PM10-2.5 , indoor endotoxin concentrations were higher than outdoor concentrations, and the indoor endotoxin concentrations significantly correlated with outdoor concentrations in each fraction (R(2) =0.458 and 0.198, respectively). Indoor endotoxin concentrations in PM2.5 were significantly higher in homes with tatami or carpet flooring and in homes with pets, and lower in homes that used air purifiers. Indoor endotoxin concentrations in PM10-2.5 were significantly higher in homes with two or more children and homes with tatami or carpet flooring. These results showed that the indoor endotoxin concentrations were associated with the household characteristics in addition to outdoor endotoxin concentrations.

  7. Relating urban airborne particle concentrations to shipping using carbon based elemental emission ratios

    NASA Astrophysics Data System (ADS)

    Johnson, Graham R.; Juwono, Alamsyah M.; Friend, Adrian J.; Cheung, Hing-Cho; Stelcer, Eduard; Cohen, David; Ayoko, Godwin A.; Morawska, Lidia

    2014-10-01

    This study demonstrates a novel method for testing the hypothesis that variations in primary and secondary particle number concentration (PNC) in urban air are related to residual fuel oil combustion at a coastal port lying 30 km upwind, by examining the correlation between PNC and airborne particle composition signatures chosen for their sensitivity to the elemental contaminants present in residual fuel oil. Residual fuel oil combustion indicators were chosen by comparing the sensitivity of a range of concentration ratios to airborne emissions originating from the port. The most responsive were combinations of vanadium and sulphur concentration ([S], [V]) expressed as ratios with respect to black carbon concentration ([BC]). These correlated significantly with ship activity at the port and with the fraction of time during which the wind blew from the port. The average [V] when the wind was predominantly from the port was 0.52 ng m-3 (87%) higher than the average for all wind directions and 0.83 ng m-3 (280%) higher than that for the lowest vanadium yielding wind direction considered to approximate the natural background. Shipping was found to be the main source of V impacting urban air quality in Brisbane. However, contrary to the stated hypothesis, increases in PNC related measures did not correlate with ship emission indicators or ship traffic. Hence at this site ship emissions were not found to be a major contributor to PNC compared to other fossil fuel combustion sources such as road traffic, airport and refinery emissions.

  8. 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.

  9. From Source to City: Particulate Matter Concentration and Size Distribution Data from an Icelandic Dust Storm

    NASA Astrophysics Data System (ADS)

    Thorsteinsson, T.; Mockford, T.; Bullard, J. E.

    2015-12-01

    Dust storms are the source of particulate matter in 20%-25% of the cases in which the PM10health limit is exceeded in Reykjavik; which occurred approximately 20 times a year in 2005-2010. Some of the most active source areas for dust storms in Iceland, contributing to the particulate matter load in Reykjavik, are on the south coast of Iceland, with more than 20 dust storm days per year (in 2002-2011). Measurements of particle matter concentration and size distribution were recorded at Markarfljot in May and June 2015. Markarfljot is a glacial river that is fed by Eyjafjallajokull and Myrdalsjokull, and the downstream sandur areas have been shown to be significant dust sources. Particulate matter concentration during dust storms was recorded on the sandur area using a TSI DustTrak DRX Aerosol Monitor 8533 and particle size data was recorded using a TSI Optical Particle Sizer 3330 (OPS). Wind speed was measured using cup anemometers at five heights. Particle size measured at the source area shows an extremely fine dust creation, PM1 concentration reaching over 5000 μg/m3 and accounting for most of the mass. This is potentially due to sand particles chipping during saltation instead of breaking uniformly. Dust events occurring during easterly winds were captured by two permanent PM10 aerosol monitoring stations in Reykjavik (140 km west of Markarfljot) suggesting the regional nature of these events. OPS measurements from Reykjavik also provide an interesting comparison of particle size distribution from source to city. Dust storms contribute to the particular matter pollution in Reykjavik and their small particle size, at least from this source area, might be a serious health concern.

  10. Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit

    PubMed Central

    Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J.; Banfield, Jillian F.; Nazaroff, William W.

    2016-01-01

    Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses’ station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3–1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3–10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37–81%. Near-room indoor emissions and outdoor sources contributed 18–59% and 1–5%, respectively. Airborne particle levels in the size range 1–10 μm showed strong dependence on human activities, indicating the importance of indoor

  11. Causes of variability in concentrations and diastereomer patterns of hexabromocyclododecanes in indoor dust.

    PubMed

    Harrad, Stuart; Abdallah, Mohamed Abou-Elwafa; Covaci, Adrian

    2009-04-01

    The temporal evolution of concentrations of alpha-, beta-, and gamma-hexabromocyclododecanes (HBCDs), and pentabromocyclododecenes (PBCDs--degradation products of HBCDs) was studied in separate aliquots of a well-homogenized indoor dust sample. These were: (a) exposed to natural light, and (b) kept in the dark. Results revealed a rapid photolytically-mediated shift from gamma-HBCD to alpha-HBCD that was complete after 1 week of exposure, and a slower degradative loss of HBCDs via elimination of HBr. Under the specific conditions studied in this experiment, calculated half-lives (t(1/2)) showed the decay in SigmaHBCDs concentration was faster in light-exposed samples (t(1/2)=12 weeks), than in light-shielded dust (t(1/2)=26 weeks). Within-room spatial and temporal variability in concentrations and diastereomer patterns were studied in six and three rooms respectively. While in some rooms, little variability was detected, in others it was substantial. In one room, concentrations of SigmaHBCDs and the relative abundance of gamma-HBCD declined dramatically with increasing distance from a TV. The same TV appears to have influenced strongly the temporal variation in that room; with higher concentrations observed in its presence and when the TV was moved closer to the area sampled. Significant negative correlation was observed in one room between concentrations of SigmaHBCDs and dust loading (g dust m(-2) floor), implying "dilution" occurs at higher dust loadings.

  12. Empirical Model for Evaluating PM10 Concentration Caused by River Dust Episodes.

    PubMed

    Lin, Chao-Yuan; Chiang, Mon-Ling; Lin, Cheng-Yu

    2016-06-02

    Around the estuary of the Zhuo-Shui River in Taiwan, the waters recede during the winter, causing an increase in bare land area and exposing a large amount of fine earth and sand particles that were deposited on the riverbed. Observations at the site revealed that when northeastern monsoons blow over bare land without vegetation or water cover, the fine particles are readily lifted by the wind, forming river dust, which greatly endangers the health of nearby residents. Therefore, determining which factors affect river dust and constructing a model to predict river dust concentration are extremely important in the research and development of a prototype warning system for areas at risk of river dust emissions. In this study, the region around the estuary of the Zhuo-Shui River (from the Zi-Qiang Bridge to the Xi-Bin Bridge) was selected as the research area. Data from a nearby air quality monitoring station were used to screen for days with river dust episodes. The relationships between PM10 concentration and meteorological factors or bare land area were analyzed at different temporal scales to explore the factors that affect river dust emissions. Study results showed that no single factor alone had adequate power to explain daily average or daily maximum PM10 concentration. Stepwise regression analysis of multiple factors showed that the model could not effectively predict daily average PM10 concentration, but daily maximum PM10 concentration could be predicted by a combination of wind velocity, temperature, and bare land area; the coefficient of determination for this model was 0.67. It was inferred that river dust episodes are caused by the combined effect of multiple factors. In addition, research data also showed a time lag effect between meteorological factors and hourly PM10 concentration. This characteristic was applied to the construction of a prediction model, and can be used in an early warning system for local residents.

  13. Empirical Model for Evaluating PM10 Concentration Caused by River Dust Episodes

    PubMed Central

    Lin, Chao-Yuan; Chiang, Mon-Ling; Lin, Cheng-Yu

    2016-01-01

    Around the estuary of the Zhuo-Shui River in Taiwan, the waters recede during the winter, causing an increase in bare land area and exposing a large amount of fine earth and sand particles that were deposited on the riverbed. Observations at the site revealed that when northeastern monsoons blow over bare land without vegetation or water cover, the fine particles are readily lifted by the wind, forming river dust, which greatly endangers the health of nearby residents. Therefore, determining which factors affect river dust and constructing a model to predict river dust concentration are extremely important in the research and development of a prototype warning system for areas at risk of river dust emissions. In this study, the region around the estuary of the Zhuo-Shui River (from the Zi-Qiang Bridge to the Xi-Bin Bridge) was selected as the research area. Data from a nearby air quality monitoring station were used to screen for days with river dust episodes. The relationships between PM10 concentration and meteorological factors or bare land area were analyzed at different temporal scales to explore the factors that affect river dust emissions. Study results showed that no single factor alone had adequate power to explain daily average or daily maximum PM10 concentration. Stepwise regression analysis of multiple factors showed that the model could not effectively predict daily average PM10 concentration, but daily maximum PM10 concentration could be predicted by a combination of wind velocity, temperature, and bare land area; the coefficient of determination for this model was 0.67. It was inferred that river dust episodes are caused by the combined effect of multiple factors. In addition, research data also showed a time lag effect between meteorological factors and hourly PM10 concentration. This characteristic was applied to the construction of a prediction model, and can be used in an early warning system for local residents. PMID:27271642

  14. Effects of airborne World Trade Center dust on cytokine release by primary human lung cells in vitro.

    PubMed

    Payne, J P; Kemp, S J; Dewar, A; Goldstraw, P; Kendall, M; Chen, L C; Tetley, T D

    2004-05-01

    There are continuing concerns regarding the respiratory health effects of airborne particulate matter (PM) after the destruction of the World Trade Centre (WTC). We examined cytokine (interleukin [IL]-8, IL-6, tumor necrosis factor-alpha) release by primary human lung alveolar macrophages (AM) and type II epithelial cells after exposure to WTC PM2.5 (indoor and outdoor), PM10-2.5 (indoor), and PM53-10 (outdoor), fractionated from settled dusts within 2 months of the incident. There was an increase in AM cytokine/chemokine release at 5 and/or 50 microg/well WTC PM, which fell at 500 microg/well. Type II cells did not release tumor necrosis factor-alpha, and the increase in IL-8 and IL-6, although significant, was lower than that of AM. Respirable PM generated by the WTC collapse stimulates inflammatory mediator release by lung cells, which may contribute to the increased incidence of respiratory illness since September 11th 2001.

  15. Inactivation of Airborne Bacteria and Viruses Using Extremely Low Concentrations of Chlorine Dioxide Gas.

    PubMed

    Ogata, Norio; Sakasegawa, Miyusse; Miura, Takanori; Shibata, Takashi; Takigawa, Yasuhiro; Taura, Kouichi; Taguchi, Kazuhiko; Matsubara, Kazuki; Nakahara, Kouichi; Kato, Daisuke; Sogawa, Koushirou; Oka, Hiroshi

    2016-01-01

    Infectious airborne microbes, including many pathological microbes that cause respiratory infections, are commonly found in medical facilities and constitute a serious threat to human health. Thus, an effective method for reducing the number of microbes floating in the air will aid in the minimization of the incidence of respiratory infectious diseases. Here, we demonstrate that chlorine dioxide (ClO2) gas at extremely low concentrations, which has no detrimental effects on human health, elicits a strong effect to inactivate bacteria and viruses and significantly reduces the number of viable airborne microbes in a hospital operating room. In one set of experiments, a suspension of Staphylococcus aureus, bacteriophage MS2, and bacteriophage ΦX174 were released into an exposure chamber. When ClO2 gas at 0.01 or 0.02 parts per million (ppm, volume/volume) was present in the chamber, the numbers of surviving microbes in the air were markedly reduced after 120 min. The reductions were markedly greater than the natural reductions of the microbes in the chamber. In another experiment, the numbers of viable airborne bacteria in the operating room of a hospital collected over a 24-hour period in the presence or absence of 0.03 ppm ClO2 gas were found to be 10.9 ± 6.7 and 66.8 ± 31.2 colony-forming units/m3 (n = 9, p < 0.001), respectively. Taken together, we conclude that ClO2 gas at extremely low concentrations (≤0.03 ppm) can reduce the number of viable microbes floating in the air in a room. These results strongly support the potential use of ClO2 gas at a non-toxic level to reduce infections caused by the inhalation of pathogenic microbes in nursing homes and medical facilities.

  16. Airborne Mold and Endotoxin Concentrations in New Orleans, Louisiana, after Flooding, October through November 2005

    PubMed Central

    Solomon, Gina M.; Hjelmroos-Koski, Mervi; Rotkin-Ellman, Miriam; Hammond, S. Katharine

    2006-01-01

    Background The hurricanes and flooding in New Orleans, Louisiana, in October and November 2005 resulted in damp conditions favorable to the dispersion of bioaerosols such as mold spores and endotoxin. Objective Our objective in this study was to assess potential human exposure to bioaerosols in New Orleans after the flooding of the city. Methods A team of investigators performed continuous airborne sampling for mold spores and endotoxin outdoors in flooded and nonflooded areas, and inside homes that had undergone various levels of remediation, for periods of 5–24 hr during the 2 months after the flooding. Results The estimated 24-hr mold concentrations ranged from 21,000 to 102,000 spores/m3 in outdoor air and from 11,000 to 645,000 spores/m3 in indoor air. The mean outdoor spore concentration in flooded areas was roughly double the concentration in nonflooded areas (66,167 vs. 33,179 spores/m3; p < 0.05). The highest concentrations were inside homes. The most common mold species were from the genera of Cladosporium and Aspergillus/Penicillium; Stachybotrys was detected in some indoor samples. The airborne endotoxin concentrations ranged from 0.6 to 8.3 EU (endo-toxin units)/m3 but did not vary with flooded status or between indoor and outdoor environments. Conclusions The high concentration of mold measured indoors and outdoors in the New Orleans area is likely to be a significant respiratory hazard that should be monitored over time. Workers and returning residents should use appropriate personal protective equipment and exposure mitigation techniques to prevent respiratory morbidity and long-term health effects. PMID:16966092

  17. The effect of dust emissions from open storage piles to particle ambient concentration and human exposure.

    PubMed

    Chalvatzaki, E; Aleksandropoulou, V; Glytsos, T; Lazaridis, M

    2012-12-01

    The current study focus on the determination of dust emissions from piles in open storage yards of a municipal solid waste (MSW) composting site and the subsequent atmospheric dust dispersion. The ISC3-ST (Industrial Source Complex Version 3 - Short Term) model was used for the evaluation of the PM(10) ambient concentrations associated with the dispersion of MSW compost dust emissions in air. Dust emission rates were calculated using the United States Environmental Protection Agency proposed dust resuspension formulation from open storage piles using local meteorological data. The dispersion modelling results on the spatial distribution of PM(10) source depletion showed that the maximum concentrations were observed at a distance 25-75 m downwind of the piles in the prevailing wind direction. Sensitivity calculations were performed also to reveal the effect of the compost pile height, the friction velocity and the receptor height on the ambient PM(10) concentration. It was observed that PM(10) concentrations (downwind in the prevailing wind direction) increased with increasing the friction velocity, increasing the pile height (for distances greater than 125 m from the source) and decreasing the receptor height (for distances greater than 125 m from the source). Furthermore, the results of ISC3-ST were analysed with the ExDoM (Exposure Dose Model) human exposure model. The ExDoM is a model for calculating the human exposure and the deposition dose, clearance, and finally retention of aerosol particles in the human respiratory tract (RT). PM(10) concentration at the composting site was calculated as the sum of the concentration from compost pile dust resuspension and the background concentration. It was found that the exposure to PM(10) and deposited lung dose for an adult Caucasian male who is not working at the composting site is less by 20-74% and 29-84%, respectively, compared to those for a worker exposed to PM concentrations at the composting site.

  18. Assessing the performance of methods to detect and quantify African dust in airborne particulates.

    PubMed

    Viana, Mar; Salvador, Pedro; Artíñano, Begoña; Querol, Xavier; Alastuey, Andrés; Pey, Jorge; Latz, Achim J; Cabañas, Mercè; Moreno, Teresa; García dos Santos, Saúl; Herce, María Dolores; Diez Hernández, Pablo; Romero García, Dolores; Fernández-Patier, Rosalía

    2010-12-01

    African dust (AD) contributions to particulate matter (PM) levels may be reported by Member States to the European Commission during justification of exceedances of the daily limit value (DLV). However, the detection and subsequent quantification of the AD contribution to PM levels is complex, and only two measurement-based methods are available in the literature: the Spanish-Portuguese reference method (SPR), and the Tel Aviv University method (TAU). In the present study, both methods were assessed. The SPR method was more conservative in the detection of episodes (71 days identified as AD by SPR, vs 81 by TAU), as it is less affected by interferences with local dust sources. The mean annual contribution of AD was lower with the TAU method than with SPR (2.7 vs 3.5 ± 1.5 μg/m(3)). The SPR and TAU AD time series were correlated with daily aluminum levels (a known tracer of AD), as well as with an AD source identified by the Positive Matrix Factorization (PMF) receptor model. Higher r(2) values were obtained with the SPR method than with TAU in both cases (r(2) = 0.72 vs 0.56, y = 0.05x vs y = 0.06x with aluminum levels; r(2)=0.79 vs 0.43, y = 0.8x vs y = 0.4x with the PMF source). We conclude that the SPR method is more adequate from an EU policy perspective (justification of DLV exceedances) due to the fact that it is more conservative than the TAU method. Based on our results, the TAU method requires adaptation of the thresholds in the algorithm to refine detection of low-impact episodes and avoid misclassification of local events as AD.

  19. [Concentrations and health risks of toxic metals in surface dust in kindergartens of Beijing].

    PubMed

    Duan, Heng-Yi; Wu, Ya-Tao; Wang, Jue; Liu, Zhao-Rong

    2014-08-01

    Dust intake is an important source of children's metal exposure. To explore the contamination level and health risk of toxic metals in kindergartens, surface dust samples were collected with self-made sampler in representative kindergartens in urban Beijing and concentrations of Pb, Hg, Cd, As were analyzed. It was found that Cd, Hg, Pb accumulated in indoor dust in different degrees with a significant seasonal variation. The geometric means of Pb, Cd, Hg, As concentrations were 63.12 microg x g(-1), 1.67 microg x g(-1), 0.06 microg x g(-1), 0.22 microg x g(-1) in summer and 117.40 microg x g(-1), 4.52 microg x g(-1), 0.95 microg x g(-1), 0.88 microg x g(-1) in winter, respectively. Geo-accumulation indexes calculated for each metal showed a severe contamination of Pb and Cd in indoor surface dusts. The results of exposure and health risk assessment of target substances displayed that the oral intake of dust metals was much higher than that of dermal pathways for children. However, no obvious carcinogenic and non-carcinogenic risks were found for all metals. The Pb, against other species, had the highest non-carcinogenic risk to children, Hazard Index of which was 0.12. Therefore, the health risk of Ph in indoor dust should raise the concern.

  20. Survival of Airborne Bacteria in a High Urban Concentration of Carbon Monoxide1

    PubMed Central

    Lighthart, Bruce

    1973-01-01

    Vegetative cells of Serratia marcescens 8UK, Sarcina lutea, and spores of Bacillus subtilus var. niger were held in aerosols, with and without an urban concentration of CO (85 μliters per liter or ppm), for up to 6 hr at 15 C and a relative humidity (RH) of approximately 0, 25, 50, 75, and 95%. It was found that CO enhanced the death rate of S. marcescens 8UK at least four- to sevenfold at low RH (ca. 1 to 25%), but protected the cells at high RH (ca. 90%). Death rates of S. lutea, with or without added CO, were comparatively low over the entire RH range. However, in the first hour, airborne S. lutea held in CO-containing air were more stable than those in air without added CO (i.e., CO protection). A marked increase in the death rate (up to 70-fold) occurred in the subsequent 5 hr within the RH range of approximately 0 to 75%. Statistical analysis indicated that aerosol decay rates of B. subtilus var. niger spores decreased significantly, when held in a CO-containing as compared to a non-CO-containing atmosphere, in the 0 to 85% RH range. Thus, the data presented indicate that CO in the urban environment may have a protective or lethal effect on airborne bacteria, dependent upon at least the microbial species, aerosol age, and relative humidity. A mechanism for CO death enhancement and protection of airborne S. marcescens 8UK is suggested to involve CO uncoupling of an energy-requiring death mechanism and an energy-requiring maintenance mechanism at high and low RH, respectively. PMID:4631439

  1. Airborne particle concentration and meteorologic conditions associated with pneumonia incidence in feedlot cattle

    SciTech Connect

    MacVean, D.W.; Franzen, D.K.; Keefe, T.J.; Bennett, B.W.

    1986-12-01

    To elucidate the role of air quality on the occurrence of pneumonia in feedlot cattle, the following environmental values were measured at a feedlot: suspended particulates in 5 particle-size fractions, relative humidity, air temperature, and barometric pressure. Pneumonia incidence data were classified by the number of days the cattle had been at the feedlot (days on feed). The concentration of airborne particles, range of temperature, days on feed, and season of the year were associated with incidence of pneumonia in cattle. Pneumonia incidence rates were greatest both within 15 days of arrival at the feedlot and during the fall sampling periods. The incidence of pneumonia in the 16 to 30 days-on-feed group was closely associated with the concentration of particles 2.0 to 3.3 microns in diameter and the range of daily temperature when exposure occurred 15 days before the onset of disease in the fall and 10 days before in the spring.

  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. Polyfluorinated compounds in dust from homes, offices, and vehicles as predictors of concentrations in office workers’ serum

    PubMed Central

    Fraser, Alicia J; Webster, Thomas F; Watkins, Deborah J; Strynar, Mark J; Kato, Kayoko; Calafat, Antonia M; Vieira, Verónica M; McClean, Michael D

    2013-01-01

    We aimed to characterize levels of polyfluorinated compounds (PFCs) in indoor dust from offices, homes, and vehicles; to investigate factors that may affect PFC levels in dust; and to examine the associations between PFCs in dust and office workers’ serum. Dust samples were collected in 2009 from offices, homes, and vehicles of 31 individuals in Boston, MA and analyzed for nineteen PFCs, including perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), fluorotelomer alcohols (FTOHs), and sulfonamidoethanols (FOSEs). Serum was collected from each participant and analyzed for eight PFCs including PFOA and PFOS. Perfluorononanoate, PFOA, perfluoroheptanoate, perfluorohexanoate, PFOS and 8:2 FTOH had detection frequencies >50% in dust from all three microenvironments. The highest geometric mean concentration in office dust was for 8:2 FTOH (309 ng/g), while PFOS was highest in homes (26.9 ng/g) and vehicles (15.8 ng/g). Overall, offices had the highest PFC concentrations, particularly for longer-chain carboxylic acids and FTOHs. Perfluorobutyrate was prevalent in homes and vehicles, but not offices. PFOA serum concentrations were not associated with PFC dust levels after adjusting for PFC concentrations in office air. Dust concentrations of most PFCs are higher in offices than in homes and vehicles. However, indoor dust may not be a significant source of exposure to PFCs for office workers. This finding suggests that our previously published observation of an association between FTOH concentrations in office air and PFOA concentrations in office workers was not due to confounding by PFCs in dust. PMID:24041736

  6. The effect of a fireworks event on the amount and elemental concentration of deposited dust collected in the city of Debrecen, Hungary.

    PubMed

    Baranyai, Edina; Simon, Edina; Braun, Mihály; Tóthmérész, Béla; Posta, József; Fábián, István

    Many social celebrations in urban areas are followed by fireworks show. The organic and inorganic pollutants emitted during detonations are expected to affect the ambient air quality of these celebration sites. The environmental aspects of fireworks events are usually investigated by analyzing the concentration and composition of airborne particulate matter, while there is limited information regarding the effect of fireworks on the elemental concentration of deposited dust. In this study, foliage dust samples were collected in the city of Debrecen (Hungary) before and after the fireworks show, organized on the 20th of August for the celebration of a historical event. Leaf samples (Tilia tomentosa) were collected around the location of the area of festivities. The sampling sites were further divided into five areas: city center (center), Southeast (SE), Southwest (SW), Northeast (NE), and Northwest (NW). We found that the amount of deposited dust particles increased significantly after the fireworks show compared to the background; we also found significant differences in the amount of dust deposition between the different locations of the city. A statistically higher level of Ca, Mg, and Sr was detected in samples collected after the display compared to those collected during the previous days, while the concentration of other studied elements were not statistically different from the background level. Our study confirmed previous findings that the relatively high altitude of detonations allows chemicals to disperse in the fine and ultrafine aerosol fractions; thus, the emitted pollutants by fireworks shows do not increase the level of elements as markedly in deposited dust as in the inhalable fraction.

  7. African dust outbreaks over the Mediterranean Basin during 2001-2011: concentrations, phenomenology and trends

    NASA Astrophysics Data System (ADS)

    Pey, Jorge; Querol, Xavier; Alastuey, Andres; Forastiere, Franceso; Stafoggia, Massimo

    2013-04-01

    Concentrations, phenomenology and trends of African dust outbreaks over the whole Mediterranean Basin werestudied on an 11-year period (2001-2011). This work has been performed in the context of the MED-PARTICLES (LIFE programme, EU) project, devoted to quantify short-term health effects of particulate matter over the Mediterranean region by distinguishing different particle sizes, chemical components and sources, with emphasis in the effects of African dust. In order to evaluate conduct this investigation, PM10 data from 19 regional and suburban background sites West to East in the Mediterranean area were compiled. After identifying the daily occurrence of African dust outbreaks, a methodology for estimating natural dust contributions on daily PM10 concentrations was applied. Our findings point out that African dust outbreaks are sensibly more frequent in southern sitesacross the Mediterranean, from 30 to 37 % of the annual days, whereas they occur less than 20% of the annual days in northern sites. The central Mediterranean emerges as a transitional area, with slightly higher frequency of dust episodes in its lower extreme when compared to similar latitudinal positions in western and eastern sides of the Basin. A decreasing south to north gradient of African dust contribution to PM10, driven by the latitudinal position of the monitoring sites at least 25°E westwards across the Basin,is patent across the Mediterranean. From 25°E eastwards, higher annual dust contributions are encountered due to the elevated annual occurrence of severe episodesof dust but also because of inputs from Middle Eastern deserts. Concerning seasonality patterns and intensity characteristics, a clear summer prevalence is observed in the western part, with low occurrence of severe episodes (daily dust averages over 100 µg m-3 in PM10); no seasonal trend is detected in the central region, with moderate-intensity episodes; and significantly higher contributions are common in autumn

  8. Concentrations and identification of culturable airborne fungi in underground stations of the Seoul metro.

    PubMed

    Hwang, Sung Ho; Jang, Soojin; Park, Wha Me; Park, Jae Bum

    2016-10-01

    The purpose of this study was to measure the culturable airborne fungi (CAF) concentrations in the underground subway stations of Seoul, Korea at two time points. This study measured the CAF concentrations in enclosed environments at 16 underground stations of the Seoul Metro in 2006 and 2013 and investigated the effects of various environmental factors, including the presence of platform screen doors, temperature, relative humidity, and number of passengers. CAF concentrations at the stations in 2006 were significantly higher than that at the same stations in 2013 (p < 0.001). Furthermore, there was a significant correlation between CAF concentration and relative humidity (r = 0.311, p < 0.05). Geotrichum and Penicillium were the predominant genera. The CAF concentrations in stations with an operating supply air were significantly higher than that in stations with no supply air (p < 0.001). Therefore, it is recommended that special attention be given to stations with clean supplied air to improve the indoor air quality of these subway stations.

  9. Concentrations and properties of airborne particles in the Mexico City subway system

    NASA Astrophysics Data System (ADS)

    Mugica-Álvarez, V.; Figueroa-Lara, J.; Romero-Romo, M.; Sepúlveda-Sánchez, J.; López-Moreno, T.

    2012-03-01

    Samples of PM10 and PM2.5 were collected using High Vol and MiniVol devices on the platform of a subway station in Mexico City and in an outdoor location close to it, using such devices. Soluble extractable organic matter (SEOM) and water solubility of metals were determined. Elemental composition and solubility of trace metals were determined and individual aerosol particles were studied with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX). The concentration levels in both sizes were similar during all days with the exception of weekends, especially on Sunday when activity decreases due to lower trains' frequency. The largest particles concentrations in the subway were found from 06:00 to 14:00 and the lowest concentrations were registered from 22:00 to 06:00. Concentrations of PM2.5 ranging between 60 μg m-3 and 93 μg m-3 (10% and 90% percentile) in the subway were 6% larger than outside, whereas PM10 were 20% larger than outside ranging from 88 μg m-3 to 145 μg m-3. Greater Fe, Cu, Ni, Cr and Mn concentrations were quantified in the subway samples as compared to the airborne particles by up to 2.5, 9, 1.8, 2.0 and 2.6 times, respectively. Even when the solubility percent of these metals in the subway PM was smaller than in the outdoor airborne particles, metals' concentrations were greater. SEM and EDS exhibit the presence of many individual particles with a large metal content in the subway samples. Correlation analysis showed the influence of outdoor PM in the subway aerosols, but characterization revealed also important differences in the presence of metals and SEOM, due to underground sources such as friction, brake system, and metals from sparking. This means that a large number of commuters are exposed during labor days to large toxic metals concentrations as they transit.

  10. Imaging-based dust sensors: equipment and methods

    NASA Astrophysics Data System (ADS)

    Bonifazi, Giuseppe; Greco, Sonia

    2004-05-01

    Dust detection and control in real time, represent one of the most challenging problem in all those environments where fine and ultrafine airborne particulate solids products are present. The presence of such products can be linked to several factors, often directly related and influenced by the working-production actions performed. Independently from the causes generating dust, airborne contaminants are an occupational problem of increasing interest as they are related to a wide number of diseases. In particular, airborne dusts are well known to be associated with several classical occupational lung diseases, such as the pneumoconiosis, especially at high levels of exposure. Nowadays there is also an increasing interest in other dust related diseases, from the most serious as cancer and asthma, to those related with allergies or irritation and other illnesses, also occurring at lower levels of exposure. Among the different critical factors influencing health risk for airborne dust exposure, mainly four have to be considered, that is: i) nature of the dust resulting from working in terms of presence of specific poisoning material, i.e. free silica, and morphological and morphometrical attributes of particulates constituting airborne dust; ii) size of the particles, iii) duration of exposure time and, finally, iv) airborne dust concentration in the breathing zone where the worker performs his activity. A correct dust detection is not easy, especially if some of the previous mentioned factors, have to be detected and quantified in real time in order to define specific "on-line" control actions aimed to reduce the level of the exposure to dust of the workers, as for example: i) modification of aspirating devices operating condition, change of filtering cleaning sequence, etc. . The more severe are the environmental conditions, in terms of dust presence (in quantity and quality) more difficult is to utilize efficient sampling devices. Detection devices, in fact, tend

  11. 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

  12. Investigation of bacterial effects of Asian dust events through comparison with seasonal variability in outdoor airborne bacterial community

    NASA Astrophysics Data System (ADS)

    Park, Jonguk; Ichijo, Tomoaki; Nasu, Masao; Yamaguchi, Nobuyasu

    2016-10-01

    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.

  13. Deriving the concentration of airborne ash with a CAS-DPOL instrument: assessing uncertainties introduced by the instrument design

    NASA Astrophysics Data System (ADS)

    Spanu, Antonio; Weinzierl, Bernadett; Freudenthaler, Volker; Sauer, Daniel; Gasteiger, Josef

    2016-04-01

    Explosive volcanic eruptions inject large amounts of gas and particles into the atmosphere resulting in strong impacts on anthropic systems and climate. Fine ash particles in suspension, even if at low concentrations, are a serious aviation safety hazard. A key point to predict the dispersion and deposition of volcanic ash is the knowledge of emitted mass and its particle size distribution. Usually the deposit is used to characterize the source but a large uncertainty is present for fine and very fine ash particles which are usually not well preserved. Conversely, satellite observations provide only column-integrated information and are strongly sensitive to cloud conditions above the ash plumes. Consequently, in situ measurements are fundamental to extend our knowledge on ash clouds, their properties, and interactions over the vertical extent of the atmosphere. Different in-situ instruments are available covering different particle size ranges using a variety of measurement techniques. Depending on the measurement technique, artefacts due to instrument setup and ambient conditions can strongly modify the measured number concentration and size distribution of the airborne particles. It is fundamental to correct for those effects to quantify the uncertainty associated with the measurement. Here we evaluate the potential of our optical light-scattering spectrometer CAS-DPOL to detect airborne mineral dust and volcanic ash (in the size range between 0.7μm and 50μm) and to provide a reliable estimation of the mass concentration, investigating the associate uncertainty. The CAS-DPOL instrument sizes particles by detecting the light scattered off the particle into a defined angle. The associated uncertainty depends on the optical instrument design and on unknown particles characteristics such as shape and material. Indirect measurements of mass concentrations are statistically reconstructed using the air flow velocity. Therefore, the detected concentration is strongly

  14. Correlation between polycyclic aromatic hydrocarbons concentration and airborne particle mutagenicity in the rubber factory.

    PubMed

    Barański, B; Palus, J; Rogaczewska, T; Szymczak, W; Spiechowicz, E

    1992-01-01

    The study was undertaken to evaluate the correlation between benzo[a]pyrene and coal tar pitch volatiles concentrations and mutagenic activity of airborne particles sampled at different workplaces of the factory producing various types of tires. The solid phase of aerosols was collected on Whatman glass-fibers filters using Staplex pumps. Coal tar pitch volatiles (CTPVs) were extracted from sample filters using ultrasonic-benzene extraction and determined by the gravimetric method. Benzo[a]pyrene (BaP) analysis was performed using high performance liquid chromatography with a spectrofluorimetric detector. The mutagenic substances were extracted from collected material with acetone. The mutagenic properties were estimated with the Ames' test using S. typhimurium strain TA98 without and with S9 fraction. At nearly all workplaces the concentrations of BaP and CTPVs were within the range of 4-61 ng/m3 and 0.11-1.26 mg/m3, respectively. Only at weighing were they much higher and amounted to 172-2261 ng/m3 for BaP and 3.05-4.07 mg/m3 for CTPVs. The highest exposure to mutagenic airborne particulate matter was found at weighing (1500 rev/m3), the mixers loading level (> 500 rev/m3) and the carbon black station (> 150 rev/m3). The air mutagenic activity at other workplaces, especially at the extruder mill of the mixer (> 90 rev/m3), the two-roll mill of mixers (> 70 rev/m3), mixer I loading (> 70 rev/m3), calendering (> 70 rev/m3) and fender vulcanizing (> 80 rev/m3) was even much more higher than that found in the urban indoor and outdoor air (2-9 rev/m3).(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Potential artifacts associated with historical preparation of joint compound samples and reported airborne asbestos concentrations.

    PubMed

    Brorby, G P; Sheehan, P J; Berman, D W; Bogen, K T; Holm, S E

    2011-05-01

    Airborne samples collected in the 1970s for drywall workers using asbestos-containing joint compounds were likely prepared and analyzed according to National Institute of Occupational Safety and Health Method P&CAM 239, the historical precursor to current Method 7400. Experimentation with a re-created, chrysotile-containing, carbonate-based joint compound suggested that analysis following sample preparation by the historical vs. current method produces different fiber counts, likely because of an interaction between the different clearing and mounting chemicals used and the carbonate-based joint compound matrix. Differences were also observed during analysis using Method 7402, depending on whether acetic acid/dimethylformamide or acetone was used during preparation to collapse the filter. Specifically, air samples of sanded chrysotile-containing joint compound prepared by the historical method yielded fiber counts significantly greater (average of 1.7-fold, 95% confidence interval: 1.5- to 2.0-fold) than those obtained by the current method. In addition, air samples prepared by Method 7402 using acetic acid/dimethylformamide yielded fiber counts that were greater (2.8-fold, 95% confidence interval: 2.5- to 3.2-fold) than those prepared by this method using acetone. These results indicated (1) there is an interaction between Method P&CAM 239 preparation chemicals and the carbonate-based joint compound matrix that reveals fibers that were previously bound in the matrix, and (2) the same appeared to be true for Method 7402 preparation chemicals acetic acid/dimethylformamide. This difference in fiber counts is the opposite of what has been reported historically for samples of relatively pure chrysotile dusts prepared using the same chemicals. This preparation artifact should be considered when interpreting historical air samples for drywall workers prepared by Method P&CAM 239.

  16. High concentrations of regional dust from deserts to plains across the central Rocky Mountains, USA

    NASA Astrophysics Data System (ADS)

    Reynolds, R. L.; Munson, S. M.; Fernandez, D. P.; Neff, J. C.

    2015-12-01

    Regional mineral dust in the American Southwest affects snow-melt rates, biogeochemical cycling, visibility, and public health. We measured total suspended particulates (TSP) across a 500-km-long sampling network of five remote sites in Utah and Colorado, USA, forming a gradient in distance from major dust emitting areas. The two westernmost sites on the Colorado Plateau desert had similar TSP concentrations (2008-2012, daily average=126 μg m-3; max. daily average over a two-week period=700 μg m-3 at Canyonlands National Park, Utah), while the easternmost High Plains site, close to cropped and grazed areas in northeastern Colorado, had an average concentration of 143 μg m-3 in 2011-2012 (max. daily average=656 μg m-3). Such concentrations rank comparably with those of TSP in several African and Asian cities in the paths of frequent dust storms. Dust loadings at the two intervening montane sites decreased from the western slope of the Rocky Mountains (Telluride, daily average=68 μg m-3) to an eastern site (Niwot Ridge, daily average=58 μg m-3). Back-trajectory analyses and satellite retrievals indicated that the three westernmost sites received most dust from large desert-source regions as far as 300 km to their southwest. These sources also sometimes sent dust to the two easternmost sites, which additionally captured dust from sources north and northwest of the central Rocky Mountains as well as locally at the Plains site. The PM10 fraction accounted for <15% of TSP, but most TSP is only slightly larger (typical median size, 15-20 μm) after about 100-800 km transport distances. Correlations between TSP and PM10 values indicate increases in both fractions during regional wind storms, especially related to Pacific frontal systems during late winter to late spring. These measurements and observations indicate that most dust deposition and associated air-quality problems in the interior American West are connected to regional dust sources and not to those in

  17. Influence of population density on the concentration and speciation of metals in the soil and street dust from urban areas.

    PubMed

    Acosta, J A; Gabarrón, M; Faz, A; Martínez-Martínez, S; Zornoza, R; Arocena, J M

    2015-09-01

    Street dust and soil from high, medium and low populated cities and natural area were analysed for selected physical-chemical properties, total and chemical speciation of Zn, Pb, Cu, Cr, Cd, Co, Ni to understand the influence of human activities on metal accumulation and mobility in the environment. The pH, salinity, carbonates and organic carbon contents were similar between soil and dust from the same city. Population density increases dust/soil salinity but has no influence on metals concentrations in soils. Increases in metal concentrations with population density were observed in dusts. Cu, Zn, Pb, Cr can be mobilized more easily from dust compared to the soil. In addition, population density increase the percentage of Pb and Zn associated to reducible and carbonate phase in the dust. The behaviour of metals except Cd in soil is mainly affected by physico-chemical properties, while total metal influenced the speciation except Cr and Ni in dusts.

  18. The roles of non-extensivity and dust concentration as bifurcation parameters in dust-ion acoustic traveling waves in magnetized dusty plasma

    SciTech Connect

    Narayan Ghosh, Uday; Kumar Mandal, Pankaj Chatterjee, Prasanta

    2014-03-15

    Dust ion-acoustic traveling waves are studied in a magnetized dusty plasma in presence of static dust and non-extensive distributed electrons in the framework of Zakharov-Kuznesstov-Burgers (ZKB) equation. System of coupled nonlinear ordinary differential equations is derived from ZKB equation, and equilibrium points are obtained. Nonlinear wave phenomena are studied numerically using fourth order Runge-Kutta method. The change from unstable to stable solution and consequently to asymptotic stable of dust ion acoustic traveling waves is studied through dynamical system approach. It is found that some dramatical features emerge when the non-extensive parameter and the dust concentration parameters are varied. Behavior of the solution of the system changes from unstable to stable and stable to asymptotic stable depending on the value of the non-extensive parameter. It is also observed that when the dust concentration is increased the solution pattern is changed from oscillatory shocks to periodic solution. Thus, non-extensive and dust concentration parameters play crucial roles in determining the nature of the stability behavior of the system. Thus, the non-extensive parameter and the dust concentration parameters can be treated as bifurcation parameters.

  19. 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.

  20. 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

  1. Metagenomic Analysis of Airborne Bacterial Community and Diversity in Seoul, Korea, during December 2014, Asian Dust Event

    PubMed Central

    Cha, Seho; Srinivasan, Sathiyaraj; Jang, Jun Hyeong; Lee, Dongwook; Lim, Sora; Kim, Kyung Sang; Jheong, Weonhwa; Lee, Dong-Won; Park, Eung-Roh; Chung, Hyun-Mi; Choe, Joonho; Kim, Myung Kyum; Seo, Taegun

    2017-01-01

    Asian dust or yellow sand events in East Asia are a major issue of environmental contamination and human health, causing increasing concern. A high amount of dust particles, especially called as particulate matter 10 (PM10), is transported by the wind from the arid and semi-arid tracks to the Korean peninsula, bringing a bacterial population that alters the terrestrial and atmospheric microbial communities. In this study, we aimed to explore the bacterial populations of Asian dust samples collected during November–December 2014. The dust samples were collected using the impinger method, and the hypervariable regions of the 16S rRNA gene were amplified using PCR followed by pyrosequencing. Analysis of the sequencing data were performed using Mothur software. The data showed that the number of operational taxonomic units and diversity index during Asian dust events were higher than those during non-Asian dust events. At the phylum level, the proportions of Proteobacteria, Actinobacteria, and Firmicutes were different between Asian dust and non-Asian dust samples. At the genus level, the proportions of the genus Bacillus (6.9%), Arthrobacter (3.6%), Blastocatella (2%), Planomicrobium (1.4%) were increased during Asian dust compared to those in non-Asian dust samples. This study showed that the significant relationship between bacterial populations of Asian dust samples and non-Asian dust samples in Korea, which could significantly affect the microbial population in the environment. PMID:28122054

  2. Recent and past dust concentrations and fluxes from a developing array of Antarctic ice cores

    NASA Astrophysics Data System (ADS)

    McConnell, J. R.; Anschütz, H.; Baggenstos, D.; Das, S. B.; Isaksson, E. D.; Lawrence, R.; Layman, L.; Maselli, O.; Severinghaus, J. P.; Sigl, M.; Petit, J. R.; Grente, B.

    2012-12-01

    Continental dust is an important component of climate forcing, both because of its interaction with incoming solar and outgoing long wave radiation and because of its impact on albedo when deposited on bright surfaces such as fresh snow. Continental dust may also play an important role in ocean fertilization and carbon sequestration. Because the lifetime of dust aerosol in the atmosphere is only on the order of days to weeks, spatial and temporal variability in concentrations and fluxes is high and understanding of recent and long term changes is limited. Here we present and discuss detailed continuous, high depth resolution measurements of a range of dust proxies in a developing array of Antarctic ice cores. Included are traditional proxies such as non-sea-salt (nss) calcium and insoluble particle number and size distribution as well as less traditional proxies such as aluminum, vanadium, manganese, rare earth elements, and nss uranium which together provide important insights into how dust sources and transport may have changed in the past. The array includes a number of new shallow ice core records from East and West Antarctica spanning recent centuries to millennia, as well as Last Glacial Maximum to early Holocene records from the deep WAIS Divide and Taylor Glacier Horizontal ice cores.

  3. A CONCENTRATION OF CENTIMETER-SIZED GRAINS IN THE OPHIUCHUS IRS 48 DUST TRAP

    SciTech Connect

    Marel, N. van der; Pinilla, P.; Tobin, J.; Kempen, T. van; Andrews, S.; Ricci, L.; Birnstiel, T.

    2015-09-01

    Azimuthally asymmetric dust distributions observed with the Atacama Large Millimeter/submillimeter Array (ALMA) in transition disks have been interpreted as dust traps. We present Very Large Array Ka band (34 GHz or 0.9 cm) and ALMA Cycle 2 Band 9 (680 GHz or 0.45 mm) observations at a 0.″2 resolution of the Oph IRS 48 disk, which suggest that larger particles could be more azimuthally concentrated than smaller dust grains, assuming an axisymmetric temperature field or optically thin 680 GHz emission. Fitting an intensity model to both data demonstrates that the azimuthal extent of the millimeter emission is 2.3 ± 0.9 times as wide as the centimeter emission, marginally consistent with the particle trapping mechanism under the above assumptions. The 34 GHz continuum image also reveals evidence for ionized gas emission from the star. Both the morphology and the spectral index variations are consistent with an increase of large particles in the center of the trap, but uncertainties remain due to the continuum optical depth at 680 GHz. Particle trapping has been proposed in planet formation models to allow dust particles to grow beyond millimeter sizes in the outer regions of protoplanetary disks. The new observations in the Oph IRS 48 disk provide support for the dust trapping mechanism for centimeter-sized grains, although additional data are required for definitive confirmation.

  4. Integrating nephelometer measurements for the airborne fine particulate matter (PM 2.5) mass concentrations

    NASA Astrophysics Data System (ADS)

    Shendrikar, Arun D.; Steinmetz, William K.

    This work describes the application of integrating nephelometer measurements for the determination of airborne fine particulate matter (PM 2.5) mass concentrations. In response to over 150 complaints (spanning a period of 20 years) from local citizens of irritant fogs and pungent odors, the North Carolina Division of Air Quality conducted a monitoring program, in collaboration with the Washington Regional Air Quality Office and PCS Phosphate, Inc., to characterize air quality in the Pamlico River airshed of eastern North Carolina. The continuous monitoring from 1 May through 31 October 2000 at four sites, involved collection of air samples and subsequent quantification for reactive acidic and basic gases, aerosols and fine particulate matter (PM 2.5) using a 7-day Annular Denuder System (ADS). Additionally, the airborne concentration of the fine particulate matter (PM 2.5) was concurrently (to the ADS) monitored using a tapered element oscillating micro-balance (TEOM). Relevant meteorological data were obtained from conventional sensors installed at each sampling site. An integrating nephelometer was used for the regional visibility measurements. An integrating nephelometer was used to measure light scattering (a surrogate for visibility) continuously for 24-h per day over a 6-month period at the four sites. A linear relationship has been found for the nephelometer (Beta scat) measurements and mass data (PM 2.5) obtained both from the TEOM and ADS. The calculated correlation coefficient results between nephelometer and ADS and nephelometer and TEOM are satisfactory and close to one. This indicates that in this region, the nephelometer measurements have the potential to be a surrogate for the determination of regional airborne fine particle (PM 2.5) mass concentrations. The ratios for each of the four sampling sites using 24-h averages of nephelometer data and PM 2.5 concentrations from the ADS units and the TEOM gave an average ratio of 0.32±0.02. This value

  5. EVALUATION OF THREE CLEANING METHODS FOR REMOVING ASBESTOS FROM CARPET. DETERMINATION OF AIRBORNE ASBESTOS CONCENTRATIONS ASSOCIATED WITH EACH METHOD

    EPA Science Inventory

    This study was conducted to compare the effectiveness of three cleaning methods to remove asbestos from contaminated carpet and to determine the airborne asbestos concentrations associated with the use of each method. The carpet on which the methods were tested was naturally cont...

  6. Ambient Airborne Solids Concentrations Including Volcanic Ash at Hanford, Washington Sampling Sites Subsequent to the Mount St. Helens Eruption

    SciTech Connect

    Sehmel, G.A.

    1982-12-20

    A major eruption of Mount St. Helens occurred on May 18, 1980. Subsequently, airborne solid concentrations were measured as a function of time at two sites within the southern edge of the fallout plume about 211 km east of Mount St. Helens. This ash was a source for investigating area-wide resuspension. Rain had a variable effect on decreasing airborne concentrations from resuspension. From 0.5 to 1.5 cm of rain were required to significantly reduce airborne solid concentrations through July. For a more aged resuspension source in September, a rain of 2.0 cm had a negligible effect. A monthly average threshold-wind speed for resuspension was defined as 3.6 m/s. For monthly-average wind speeds less than the threshold wind speed, monthly-average airborne concentrations tended to decrease with time. A decrease was recorded between September and October. For this 4-month time period, the half-life was on the order of 50 days, corresponding to a weathering rate of 5.1 year/sup -1/.

  7. 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 ...

  8. Concentrations of polybrominated diphenyl ethers (PBDEs) in matched samples of human milk, dust and indoor air.

    PubMed

    Toms, Leisa-Maree L; Hearn, Laurence; Kennedy, Karen; Harden, Fiona; Bartkow, Michael; Temme, Christian; Mueller, Jochen F

    2009-08-01

    Polybrominated diphenyl ethers (PBDEs) are lipophilic, persistent pollutants found worldwide in environmental and human samples. Exposure pathways for PBDEs remain unclear but may include food, air and dust. The aim of this study was to conduct an integrated assessment of PBDE exposure and human body burden using 10 matched samples of human milk, indoor air and dust collected in 2007-2008 in Brisbane, Australia. In addition, temporal analysis was investigated comparing the results of the current study with PBDE concentrations in human milk collected in 2002-2003 from the same region. PBDEs were detected in all matrices and the median concentrations of BDEs -47 and -209 in human milk, air and dust were: 4.2 and 0.3 ng/g lipid; 25 and 7.8 pg/m(3); and 56 and 291 ng/g dust, respectively. Significant correlations were observed between the concentrations of BDE-99 in air and human milk (r=0.661, p=0.038) and BDE-153 in dust and BDE-183 in human milk (r=0.697, p=0.025). These correlations do not suggest causal relationships - there is no hypothesis that can be offered to explain why BDE-153 in dust and BDE-183 in milk are correlated. The fact that so few correlations were found in the data could be a function of the small sample size, or because additional factors, such as sources of exposure not considered or measured in the study, might be important in explaining exposure to PBDEs. There was a slight decrease in PBDE concentrations from 2002-2003 to 2007-2008 but this may be due to sampling and analytical differences. Overall, average PBDE concentrations from these individual samples were similar to results from pooled human milk collected in Brisbane in 2002-2003 indicating that pooling may be an efficient, cost-effective strategy of assessing PBDE concentrations on a population basis. The results of this study were used to estimate an infant's daily PBDE intake via inhalation, dust ingestion and human milk consumption. Differences in PBDE intake of individual

  9. Elevated house dust and serum concentrations of PBDEs in California: unintended consequences of furniture flammability standards?

    PubMed

    Zota, Ami R; Rudel, Ruthann A; Morello-Frosch, Rachel A; Brody, Julia Green

    2008-11-01

    Studies show higher house dust and body burden levels of PBDE flame retardants in North America than Europe; but little is known about exposure variation within North America, where California's furniture flammability standard affects PBDE use. We compared dust samples from 49 homes in two California communities with 120 Massachusetts homes and with other published studies. Dust concentrations [median (range) ng/g] in California homes of BDE-47, -99, and -100 were 2700 (112-107,000), 3800 (102-170,000), and 684 (concentrations were the highest ever reported in indoor dust. We then investigated whether human serum PBDE levels were also higher in California compared to other North American regions by analyzing the 2003-2004 National Health and Nutrition Examination Survey (NHANES), the only data set available with serum from a representative sample of the U.S. population (n=2040). California residence was significantly associated with nearly 2-fold higher sigma PBDE serum levels [least square geometric mean (LSGM) ng/g lipid, 73.0 vs 38.5 (p = 0.002)]. Elevated PBDE exposures in California may result from the state's furniture flammability standards; our results suggest the need for further research in a larger representative sample.

  10. Assessing inhalation exposure from airborne soil contaminants

    SciTech Connect

    Shinn, J.H.

    1998-04-01

    A method of estimation of inhalation exposure to airborne soil contaminants is presented. this method is derived from studies of airborne soil particles with radioactive tags. The concentration of contaminants in air (g/m{sup 3}) can be derived from the product of M, the suspended respirable dust mass concentration (g/m{sup 3}), S, the concentration of contaminant in the soil (g/g), and E{sub f}, an enhancement factor. Typical measurement methods and values of M, and E{sub f} are given along with highlights of experiences with this method.

  11. Wood dust particle and mass concentrations and filtration efficiency in sanding of wood materials.

    PubMed

    Welling, Irma; Lehtimäki, Matti; Rautio, Sari; Lähde, Tero; Enbom, Seppo; Hynynen, Pasi; Hämeri, Kaarle

    2009-02-01

    The importance of fine particles has become apparent as the knowledge of their effects on health has increased. Fine particle concentrations have been published for outside air, plasma arc cutting, welding, and grinding, but little data exists for the woodworking industry. Sanding was evaluated as the producer of the woodworking industry's finest particles, and was selected as the target study. The number of dust particles in different particle size classes and the mass concentrations were measured in the following environments: workplace air during sanding in plywood production and in the inlet and return air; in the dust emission chamber; and in filter testing. The numbers of fine particles were low, less than 10(4) particles/cm(3) (10(7) particles/L). They were much lower than typical number concentrations near 10(6) particles/cm(3) measured in plasma arc cutting, grinding, and welding. Ultrafine particles in the size class less than 100 nm were found during sanding of MDF (medium density fiberboard) sheets. When the cleaned air is returned to the working areas, the dust content in extraction systems must be monitored continuously. One way to monitor the dust content in the return air is to use an after-filter and measure pressure drop across the filter to indicate leaks in the air-cleaning system. The best after-filtration materials provided a clear increase in pressure drop across the filter in the loading of the filter. The best after-filtration materials proved to be quite effective also for fine particles. The best mass removal efficiencies for fine particles around 0.3 mum were over 80% for some filter materials loaded with sanding wood dust.

  12. Modeling breathing-zone concentrations of airborne contaminants generated during compressed air spray painting.

    PubMed

    Flynn, M R; Gatano, B L; McKernan, J L; Dunn, K H; Blazicko, B A; Carlton, G N

    1999-01-01

    This paper presents a mathematical model to predict breathing-zone concentrations of airborne contaminants generated during compressed air spray painting in cross-flow ventilated booths. The model focuses on characterizing the generation and transport of overspray mist. It extends previous work on conventional spray guns to include exposures generated by HVLP guns. Dimensional analysis and scale model wind-tunnel studies are employed using non-volatile oils, instead of paint, to produce empirical equations for estimating exposure to total mass. Results indicate that a dimensionless breathing zone concentration is a nonlinear function of the ratio of momentum flux of air from the spray gun to the momentum flux of air passing through the projected area of the worker's body. The orientation of the spraying operation within the booth is also very significant. The exposure model requires an estimate of the contaminant generation rate, which is approximated by a simple impactor model. The results represent an initial step in the construction of more realistic models capable of predicting exposure as a mathematical function of the governing parameters.

  13. The Continuous Monitoring of Desert Dust using an Infrared-based Dust Detection and Retrieval Method

    NASA Technical Reports Server (NTRS)

    Duda, David P.; Minnis, Patrick; Trepte, Qing; Sun-Mack, Sunny

    2006-01-01

    Airborne dust and sand are significant aerosol sources that can impact the atmospheric and surface radiation budgets. Because airborne dust affects visibility and air quality, it is desirable to monitor the location and concentrations of this aerosol for transportation and public health. Although aerosol retrievals have been derived for many years using visible and near-infrared reflectance measurements from satellites, the detection and quantification of dust from these channels is problematic over bright surfaces, or when dust concentrations are large. In addition, aerosol retrievals from polar orbiting satellites lack the ability to monitor the progression and sources of dust storms. As a complement to current aerosol dust retrieval algorithms, multi-spectral thermal infrared (8-12 micron) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Meteosat-8 Spinning Enhanced Visible and Infrared Imager (SEVIRI) are used in the development of a prototype dust detection method and dust property retrieval that can monitor the progress of Saharan dust fields continuously, both night and day. The dust detection method is incorporated into the processing of CERES (Clouds and the Earth s Radiant Energy System) aerosol retrievals to produce dust property retrievals. Both MODIS (from Terra and Aqua) and SEVERI data are used to develop the method.

  14. Biodiversity and concentrations of airborne fungi in large US office buildings from the BASE study

    NASA Astrophysics Data System (ADS)

    Tsai, Feng C.; Macher, Janet M.; Hung, Yun-Yi

    The Building Assessment Survey and Evaluation (BASE) study measured baseline concentrations of airborne fungi in 100 representative US office buildings in 1994-1998. Multiple samples for different sampling durations, sites, and times of the day were aggregated into building-wide indoor and outdoor average concentrations. Fungal concentrations were compared between locations (indoor vs. outdoor), sampling and analytical methods (culture vs. microscopy), and season (summer vs. winter). The arithmetic means (standard deviations) of the indoor/outdoor concentrations of culturable fungi and fungal spores were 100/680 (230/840) CFUm-3 and 270/6540 (1190/6780) sporem-3, respectively. Although fewer groups were observed indoors than outdoors, at lower average concentrations (except in two buildings), site-specific and building-wide indoor measurements had higher coefficients of variation. More groups were seen in summer, and aggregated concentrations tended to be higher than in winter except for culturable Aureobasidium spp. and Botrytis spp. outdoors and non-sporulating fungi in both locations. Rankings of the predominant fungi identified by both methods were similar, but overall indoor and outdoor spore concentrations were approximately 3 and 10 times higher, respectively, than concentrations of culturable fungi. In the 44 buildings with both measurements, the indoor and outdoor total culturable fungi to fungal spore ratios (total C/S ratios) were 1.27 and 0.25, with opposite seasonal patterns. The indoor C/S ratio was higher in summer than in winter (1.47 vs. 0.86; N=29 and 15, respectively), but the outdoor ratio was lower in summer (0.19 vs. 0.36, respectively). Comparison of the number of different fungal groups and individual occurrence in buildings and samples indicated that the outdoor environment and summer season were more diverse, but the proportional contributions of the groups were very similar suggesting that the indoor and outdoor environments were related

  15. Airborne Lidar Measurements of Atmospheric Column CO2 Concentration to Cloud Tops

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ramanathan, A. K.; Abshire, J. B.; Kawa, S. R.; Riris, H.; Allan, G. R.; Hasselbrack, W. E.

    2015-12-01

    Globally distributed atmospheric CO2 measurements with high precision, low bias and full seasonal sampling are crucial to advance carbon cycle sciences. However, two thirds of the Earth's surface is typically covered by clouds, and passive remote sensing approaches from space, e.g., OCO-2 and GOSAT, are limited to cloud-free scenes. They are unable to provide useful retrievals in cloudy areas where the photon path-length can't be well characterized. Thus, passive approaches have limited global coverage and poor sampling in cloudy regions, even though some cloudy regions have active carbon surface fluxes. NASA Goddard is developing a pulsed integrated-path, differential absorption (IPDA) lidar approach to measure atmospheric column CO2 concentrations from space as a candidate for NASA's ASCENDS mission. Measurements of time-resolved laser backscatter profiles from the atmosphere also allow this technique to estimate column CO2 and range to cloud tops in addition to those to the ground with precise knowledge of the photon path-length. This allows retrievals of column CO2 concentrations to cloud tops, providing much higher spatial coverage and some information about vertical structure of CO2. This is expected to benefit atmospheric transport process studies, carbon data assimilation in models, and global and regional carbon flux estimation. We show some preliminary results of the all-sky retrieval capability using airborne lidar measurements from the 2011, 2013 and 2014 ASCENDS airborne campaigns on the NASA DC-8. These show retrievals of atmospheric CO2 over low-level marine stratus clouds, cumulus clouds at the top of planetary boundary layer, some mid-level clouds and visually thin high-level cirrus clouds. The CO2 retrievals from the lidar are validated against in-situ measurements and compared to Goddard PCTM model simulations. Lidar cloud slicing to derive CO2 abundance in the planetary boundary layer and free troposphere also has been demonstrated. The

  16. [Chemical characteristics in airborne particulate matter (PM10) during a high pollution spring dust storm episode in Beijing, Tianjin and Zhangjiakou, China].

    PubMed

    Liu, Qing-Yang; Liu, Yan-Ju; Zhao, Qiang; Zhang, Ting-Ting; Zhang, Mei-Gen; Wang, Cun-Mei

    2014-08-01

    Atmospheric particulate matter (PM10) was collected at sampling locations of Beijing, Tianjin and Zhangjiakou from April 1st to May 24th, 2012. The mass concentration of PM10 and concentrations of ions, elemental carbon (EC) and organic carbon (OC) in PM10 were determined. The results showed that average mass concentration of PM10 were 233.82 microg x m(-3) for Beijing, 279.64 microg x (-3) for Tianjin and 238.13 microg x m(-3) for Zhangjiakou, respectively. Backward trajectories results confirmed dust storm events occurred from 27th to 29th April. The maximum daily mass concentrations of PM10 were 755.54 microg x m(-3) for Beijing, 831.32 microg x m(-3) for Tianjin and 582.82 microg x m(-3) for Zhangjiakou during the dust storm episodes, respectively. Water-soluble ions (Na+, NH4+, Ca2+, K+, F-, Cl-, NO3-, SO4(2-)), organic carbon (OC) and elemental carbon (EC) were major aerosol components during the dust storm episodes, and their concentrations were higher than non-dust storm days. In addition, dust storm caused increases in NO3-, SO4(2-) and enrichment of secondary organic carbon (SOC) concentration relative to OC, suggesting that chemical reaction processes involving gas-particle conversion occurred during the long-distance transport of aerosol particles.

  17. Concentration and composition variations of metals in the outdoor PM10 of elementary schools during river dust episodes.

    PubMed

    Kuo, Chung-Yih; Yang, Hao-Jan; Chiang, Yi-Chen; Lai, Dian-Jheng; Shen, Ying-Hsuan; Liu, Pang-Min

    2014-11-01

    Aeolian river dust can seriously affect the air quality in central Taiwan. The main purpose of this study was to assess the concentration variations of PM10 and metals at different elementary schools during river dust episodes. River dust samples were taken from eight sites in the main bare soil areas of the Choshui River. PM10 aerosols from four elementary schools in Yulin County were collected by means of high-volume samplers. Fifteen elements (Fe, Al, Ca, Mg, Mn, Zn, Ti, Ni, V, Cr, As, Pb, Cu, Co, and Cd) in the river dust and PM10 were analyzed in this study. The coefficients of divergence (CDs) were obtained by comparing the metal compositions in PM10 aerosols at the four schools on the sampling days with the mean metal contents in the river soil samples as reference. The CD values showed that metal compositions in the aerosols at high-exposure sites during river dust episodes were similar to those compositions in the river dust. The concentrations of PM10 at the high-exposure schools during river dust episodes were much higher than those during non-river-dust episodes. This study also indicated that at the high-exposure sites, both the PM10 and metal concentrations were higher than at the low-exposure and control sites, not only during the river dust episodes, but also after the river dust episodes. The concentrations of toxic metals (Ni, Cr, As, and Cd) at the high-exposure sites were about 11.3 times higher during the river dust episodes (189 ng/m(3)) than during non-river-dust episodes (16.7 ng/m(3)) and about 8.9 times higher during the same periods at the control site (21.3 ng/m(3)).

  18. Airborne Pollen Concentrations and Emergency Room Visits for Myocardial Infarction: A Multicity Case-Crossover Study in Ontario, Canada.

    PubMed

    Weichenthal, Scott; Lavigne, Eric; Villeneuve, Paul J; Reeves, François

    2016-04-01

    Few studies have examined the acute cardiovascular effects of airborne allergens. We conducted a case-crossover study to evaluate the relationship between airborne allergen concentrations and emergency room visits for myocardial infarction (MI) in Ontario, Canada. In total, 17,960 cases of MI were identified between the months of April and October during the years 2004-2011. Daily mean aeroallergen concentrations (pollen and mold spores) were assigned to case and control periods using central-site monitors in each city along with daily measurements of meteorological data and air pollution (nitrogen dioxide and ozone). Odds ratios and their 95% confidence intervals were estimated using conditional logistic regression models adjusting for time-varying covariates. Risk of MI was 5.5% higher (95% confidence interval (CI): 3.4, 7.6) on days in the highest tertile of total pollen concentrations compared with days in the lowest tertile, and a significant concentration-response trend was observed (P < 0.001). Higher MI risk was limited to same-day pollen concentrations, with the largest risks being observed during May (odds ratio = 1.16, 95% CI: 1.00, 1.35) and June (odds ratio = 1.10, 95% CI: 1.00, 1.22), when tree and grass pollen are most common. Mold spore concentrations were not associated with MI. Our findings suggest that airborne pollen might represent a previously unidentified environmental risk factor for myocardial infarction.

  19. Estimating PM 10 air concentrations from dust storms in Iraq, Kuwait and Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Draxler, Roland R.; Gillette, Dale A.; Kirkpatrick, Jeffrey S.; Heller, Jack

    A model for the emission of PM 10 dust has been constructed using the concept of a threshold friction velocity which is dependent on surface roughness. Surface roughness in turn was correlated with geomorphology or soil properties for Kuwait, Iraq, part of Syria, Saudi Arabia, the United Arab Emirates and Oman. The PM 10 emission algorithm was incorporated into a Lagrangian transport and dispersion model. PM 10 air concentrations were computed from August 1990 through August 1991. The model predicted about the right number of dust events over Kuwait (events occur 18% of the time). The model results agreed quantitatively with measurements at four locations in Saudi Arabia and one in Kuwait for one major dust event (>1000 μg/m 3). However, for smaller scale dust events (200-1000 μg/m 3), especially at the coastal sampling locations, the model substantially over-predicted the air concentrations. Part of the over-prediction was attributed to the entrainment of dust-free air by the sea breeze, a flow feature not represented by the large-scale gridded meteorological data fields used in the model computation. Another part of the over-prediction was the model's strong sensitivity to threshold friction velocity and the surface soil texture coefficient (the soil emission factor), and the difficulty in accurately representing these parameters in the model. A comparison of the model predicted PM 10 spatial pattern with the TOMS satellite aerosol index (AI) yielded a spatial pattern covering a major portion of Saudi Arabia that was quite similar to the observed AI pattern.

  20. Airborne hyperspectral imaging for sensing phosphorus concentration in the Lake Okeechobee drainage basin

    NASA Astrophysics Data System (ADS)

    Bogrekci, Ismail; Lee, Won Suk; Jordan, Jonathan D.

    2005-05-01

    Eutrophication disturbs the ecological balance in the Lake Okeechobee due to high concentration of phosphorus emanated from the regions in the lake's drainage basin. Ability of measuring phosphorus (P) concentrations of water in the Lake Okeechobee itself is very important. Furthermore, monitoring P in its drainage basins is crucial in order to find the cause of P loading and contributing regions. Also, inexpensive real-time sensing capability for a large area in a short time would help scientist, government agents, and civilians to understand the causes, spot the high-risk areas, and develop management practices for restoring the natural equilibrium. In order to measure P concentrations in the Lake Okeechobee drainage basin, airborne hyperspectral images were taken from five representative target sites by deploying a modified queen air twin engine aircraft. Each flight line covered a swath of approximately 365 m wide. Spatial resolution was about 1 m. Spectral range covered was between 412.65 and 991.82 nm with an approximate of 5 nm spectral resolution. Ground truthing was conducted to collect soil and vegetation samples, GPS coordinates of each location, and reflectance measurement of each sample. On the ground, spectral reflectance was measured using a handheld spectrometer in 400-2500 nm. The samples were sent to a laboratory for chemical analysis. Also diffuse reflectance of the samples was measured in a laboratory setting using a spectrophotometer with an integrating sphere. Images were geocorrected and rectified to reduce geometric effect. Calibration of images was conducted to obtain actual reflectance of the target area. Score, SAM (Spectral Angle Mapping), SFF (Spectral Feature Fitting) were computed for spectral matching with image derived spectral library.

  1. Apparatus and methods for monitoring the concentrations of hazardous airborne substances, especially lead

    DOEpatents

    Zaromb, Solomon

    2004-07-13

    Air is sampled at a rate in excess of 100 L/min, preferably at 200-300 L/min, so as to collect therefrom a substantial fraction, i.e., at least 20%, preferably 60-100%, of airborne particulates. A substance of interest (analyte), such as lead, is rapidly solubilized from the the collected particulates into a sample of liquid extractant, and the concentration of the analyte in the extractant sample is determined. The high-rate air sampling and particulate collection may be effected with a high-throughput filter cartridge or with a recently developed portable high-throughput liquid-absorption air sampler. Rapid solubilization of lead is achieved by a liquid extractant comprising 0.1-1 M of acetic acid or acetate, preferably at a pH of 5 or less and preferably with inclusion of 1-10% of hydrogen peroxide. Rapid determination of the lead content in the liquid extractant may be effected with a colorimetric or an electroanalytical analyzer.

  2. No Concentration Decrease of House Dust Mite Allergens With Rising Altitude in Alpine Regions

    PubMed Central

    Grafetstätter, Carina; Prossegger, Johanna; Braunschmid, Herbert; Sanovic, Renata; Hahne, Penelope; Pichler, Christina; Thalhamer, Josef

    2016-01-01

    Purpose Several studies over the past 4 decades have indicated a significant reduction in house dust mite (HDM) and HDM allergen concentration in areas higher than 1,500 m above sea level. These have served as basis of allergen avoidance therapies for HDM allergy and asthma. However, modern construction techniques used in the insulation, heating, and glazing of buildings as well as global warming have changed the environmental parameters for HDM living conditions. The present study revisits the paradigm of decreasing HDM allergen concentrations with increasing altitude in the alpine region of Germany and Austria. Methods A total of 122 dust samples from different abodes (hotels, privates and mountain huts) at different altitudes (400-2,600 m) were taken, and concentrations of HDM allergens were analyzed. Humidity and temperature conditions, and numerous indoor environmental parameters such as fine dust, type of flooring, age of building, and frequency of cleaning were determined. Results HDM allergen concentrations did not significantly change with increasing altitude or relative humidity. At the level of indoor parameters, correlations could be found for different flooring types and the concentration of HDM allergens. Conclusions In contrast to the widespread view of the relationship between altitude and HDM allergen concentrations, clinically relevant concentrations of HDM allergens could be detected in high-lying alpine regions in Austria and Germany. These results indicate that improvement in conditions of asthmatic patients sensitized against HDMs during a stay at high altitude can no longer be ascribed to decreased levels of HDM allergens, instead, other mechanisms may trigger the beneficial effect. PMID:27126724

  3. Concentration, Size Distribution, and Infectivity of Airborne Particles Carrying Swine Viruses

    PubMed Central

    Alonso, Carmen; Raynor, Peter C.; Davies, Peter R.; Torremorell, Montserrat

    2015-01-01

    When pathogens become airborne, they travel associated with particles of different size and composition. Particle size determines the distance across which pathogens can be transported, as well as the site of deposition and the survivability of the pathogen. Despite the importance of this information, the size distribution of particles bearing viruses emitted by infectious animals remains unknown. In this study we characterized the concentration and size distribution of inhalable particles that transport influenza A virus (IAV), porcine reproductive and respiratory syndrome virus (PRRSV), and porcine epidemic diarrhea virus (PEDV) generated by acutely infected pigs and assessed virus viability for each particle size range. Aerosols from experimentally infected pigs were sampled for 24 days using an Andersen cascade impactor able to separate particles by size (ranging from 0.4 to 10 micrometer (μm) in diameter). Air samples collected for the first 9, 20 and the last 3 days of the study were analyzed for IAV, PRRSV and PEDV, respectively, using quantitative reverse transcription polymerase chain reaction (RT-PCR) and quantified as geometric mean copies/m3 within each size range. IAV was detected in all particle size ranges in quantities ranging from 5.5x102 (in particles ranging from 1.1 to 2.1μm) to 4.3x105 RNA copies/m3 in the largest particles (9.0–10.0μm). PRRSV was detected in all size ranges except particles between 0.7 and 2.1μm in quantities ranging from 6x102 (0.4–0.7μm) to 5.1x104 RNA copies/m3 (9.0–10.0μm). PEDV, an enteric virus, was detected in all particle sizes and in higher quantities than IAV and PRRSV (p < 0.0001) ranging from 1.3x106 (0.4–0.7μm) to 3.5x108 RNA copies/m3 (9.0–10.0μm). Infectious status was demonstrated for the 3 viruses, and in the case of IAV and PRRSV, viruses were isolated from particles larger than 2.1μm. In summary, our results indicated that airborne PEDV, IAV and PRRSV can be found in a wide range of

  4. DIFFERENTIAL LUNG GENE EXPRESSION IN IMMUNOLOGICALLY-CHALLENGED RATS EXPOSED TO CONCENTRATED AIRBORNE PARTICULATES

    EPA Science Inventory

    Children residing in urbanized areas suffer disproportionately higher asthma-related morbidity and mortality. One explanation is that inner city children are exposured to higher levels of environmental asthma triggers such as airborne particulate matter. To elucidate gene-environ...

  5. Pulsed Lidar Measurements of Atmospheric CO2 Column Concentration in the ASCENDS 2014 Airborne Campaign

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.; Ramanathan, A. K.; Mao, J.; Riris, H.; Allan, G. R.; Hasselbrack, W. E.; Chen, J. R.

    2015-12-01

    We report progress in demonstrating a pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. The CO2 lidar flies on NASA's DC-8 aircraft and measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line by using 30 wavelength samples distributed across the lube. Our post-flight analysis estimates the lidar range and pulse energies at each wavelength 10 times per second. The retrievals solve for the optimum CO2 absorption line shape and the column average CO2 concentrations using radiative transfer calculations based on HITRAN, the aircraft altitude, range to the scattering surface, and the atmospheric conditions. We compare these to CO2 concentrations sampled by in-situ sensors on the aircraft. The number of wavelength samples can be reduced in the retrievals. During the ASCENDS airborne campaign in 2013 two flights were made in February over snow in the Rocky Mountains and the Central Plains allowing measurement of snow-covered surface reflectivity. Several improvements were made to the lidar for the 2014 campaign. These included using a new step-locked laser diode source, and incorporating a new HgCdTe APD detector and analog digitizer into the lidar receiver. Testing showed this detector had higher sensitivity, analog response, and a more linear dynamic range than the PMT detector used previously. In 2014 flights were made in late August and early September over the California Central Valley, the redwood forests along the California coast, two desert areas in Nevada and California, and two flights above growing agriculture in Iowa. Two flights were also made under OCO-2 satellite ground tracks. Analyses show the retrievals of lidar range and CO2 column absorption, and mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, and through thin clouds and aerosol scattering. The lidar measurements clearly

  6. Culturability and concentration of indoor and outdoor airborne fungi in six single-family homes

    NASA Astrophysics Data System (ADS)

    Lee, Taekhee; Grinshpun, Sergey A.; Martuzevicius, Dainius; Adhikari, Atin; Crawford, Carlos M.; Reponen, Tiina

    In this study, the culturability of indoor and outdoor airborne fungi was determined through long-term sampling (24-h) using a Button Personal Inhalable Aerosol Sampler. The air samples were collected during three seasons in six Cincinnati area homes that were free from moisture damage or visible mold. Cultivation and total microscopic enumeration methods were employed for the sample analysis. The geometric means of indoor and outdoor culturable fungal concentrations were 88 and 102 colony-forming units (CFU) m -3, respectively, with a geometric mean of the I/ O ratio equal to 0.66. Overall, 26 genera of culturable fungi were recovered from the indoor and outdoor samples. For total fungal spores, the indoor and outdoor geometric means were 211 and 605 spores m -3, respectively, with a geometric mean of I/ O ratio equal to 0.32. The identification revealed 37 fungal genera from indoor and outdoor samples based on the total spore analysis. Indoor and outdoor concentrations of culturable and total fungal spores showed significant correlations ( r=0.655, p<0.0001 and r=0.633, p<0.0001, respectively). The indoor and outdoor median viabilities of fungi were 55% and 25%, respectively, which indicates that indoor environment provides more favorable survival conditions for the aerosolized fungi. Among the seasons, the highest indoor and outdoor culturability of fungi was observed in the fall. Cladosporium had a highest median value of culturability (38% and 33% for indoor and outdoor, respectively) followed by Aspergillus/Penicillium (9% and 2%) among predominant genera of fungi. Increased culturability of fungi inside the homes may have important implications because of the potential increase in the release of allergens from viable spores and pathogenicity of viable fungi on immunocompromised individuals.

  7. Airborne concentrations of chrysotile asbestos in serpentine quarries and stone processing facilities in Valmalenco, Italy.

    PubMed

    Cattaneo, Andrea; Somigliana, Anna; Gemmi, Mauro; Bernabeo, Ferruccio; Savoca, Domenico; Cavallo, Domenico M; Bertazzi, Pier A

    2012-07-01

    Asbestos may be naturally present in rocks and soils. In some cases, there is the possibility of releasing asbestos fibres into the atmosphere from the rock or soil, subsequently exposing workers and the general population, which can lead to an increased risk of developing asbestos-related diseases. In the present study, air contaminated with asbestos fibres released from serpentinites was investigated in occupational settings (quarries and processing factories) and in the environment close to working facilities and at urban sites. The only naturally occurrence of asbestos found in Valmalenco area was chrysotile; amphibole fibres were never detected. An experimental cut-off diameter of 0.25 μm was established for distinguishing between Valmalenco chrysotile and antigorite single fibres using selected area electron diffraction analyses. Air contamination from chrysotile fibres in the examined occupational settings was site-dependent as the degree of asbestos contamination of Valmalenco serpentinites is highly variable from place to place. Block cutting of massive serpentinites with multiple blades or discs and drilling at the quarry sites that had the highest levels of asbestos contamination generated the highest exposures to (i.e. over the occupational exposure limits) asbestos. Conversely, working activities on foliated serpentinites produced airborne chrysotile concentrations comparable with ambient levels. Environmental chrysotile concentrations were always below the Italian limit for life environments (0.002 f ml(-1)), except for one sample collected at a quarry property boundary. The present exposure assessment study should encourage the development of an effective and concordant policy for proper use of asbestos-bearing rocks and soils as well as for the protection of public health.

  8. Ventilatory function in workers exposed to tea and wood dust.

    PubMed

    Al Zuhair, Y S; Whitaker, C J; Cinkotai, F F

    1981-11-01

    Changes in ventilatory capacity during the work shift were studied in workers exposed to tea dust in tea-packing plants, wood dust in two furniture factories, and virtually no dust in an inoperational power station. The FEV1 and FVC in workers exposed to dust were found to decline during the work shift by a small but significant volume. The MMFR, Vmax 50% and Vmax 75% were to variable to display any trend. No dose-response relationship could be discerned between the fall in workers' ventilatory capacity and the concentrations of airborne dust or microbes to which they were exposed. Bronchodilators could reverse the fall in FEV1.

  9. Radon in indoor concentrations and indoor concentrations of metal dust particles in museums and other public buildings.

    PubMed

    Carneiro, G L; Braz, D; de Jesus, E F; Santos, S M; Cardoso, K; Hecht, A A; Dias da Cunha, Moore K

    2013-06-01

    The aim of this study was to evaluate the public and occupational exposure to radon and metal-bearing particles in museums and public buildings located in the city of Rio de Janeiro, Brazil. For this study, four buildings were selected: two historic buildings, which currently house an art gallery and an art museum; and two modern buildings, a chapel and a club. Integrated radon concentration measurements were performed using passive radon detectors with solid state nuclear track detector-type Lexan used as nuclear track detector. Air samplers with a cyclone were used to collect the airborne particle samples that were analyzed by the particle-induced X-ray emission technique. The average unattached-radon concentrations in indoor air in the buildings were above 40 Bq/m(3), with the exception of Building D as measured in 2009. The average radon concentrations in indoor air in the four buildings in 2009 were below the recommended reference level by World Health Organization (100 Bq/m(3)); however, in 2011, the average concentrations of radon in Buildings A and C were above this level, though lower than 300 Bq/m(3). The average concentrations of unattached radon were lower than 148 Bq/m(3) (4pCi/L), the USEPA level recommended to take action to reduce the concentrations of radon in indoor air. The unattached-radon average concentrations were also lower than the value recommended by the European Union for new houses. As the unattached-radon concentrations were below the international level recommended to take action to reduce the radon concentration in air, it was concluded that during the period of sampling, there was low risk to human health due to the inhalation of unattached radon in these four buildings.

  10. Seasonal concentrations of lead in outdoor and indoor dust and blood of children in Riyadh, Saudi Arabia.

    PubMed

    El-Desoky, Gaber E; Aboul-Soud, Mourad A M; Al-Othman, Zeid A; Habila, Mohamed; Giesy, John P

    2014-06-01

    Because detrimental effects of exposure to lead (Pb) on human health have been observed, we previously investigated concentrations of Pb in water supplies and blood of adult residents of Riyadh, Saudi Arabia. The objectives of the present study were to: (1) examine seasonal rates of deposition of Pb in dust in several areas of Riyadh city, (2) measure concentrations of Pb in both outdoor and indoor dust, (3) compare concentrations of Pb in dust in Riyadh with those reported for other cities, and (4) quantify Pb in blood of children living in Riyadh. Mean, monthly deposition of PB in outdoor dust was 4.7 × 10(1) ± 3.6 tons km(-2), with a mean Pb concentration of 2.4 × 10(2) ± 4.4 × 10(1) μg/g. Mean, monthly deposition of Pb in indoor dust was 2.7 ± 0.70 tons km(-2), with a mean concentration of 2.9 × 10(1) ± 1.5 × 10(1) μg Pb/g. There was a significant (P < 0.01) correlation between concentrations of Pb in outdoor and indoor dust. There was no correlation between concentrations of Pb in indoor dust and that in blood of children of Riyadh, whereas there was a weakly significant (P < 0.05) correlation between concentrations of Pb in outdoor dust and that in blood of children. The mean (±SD) concentration of Pb in blood of children in Riyadh was 5.2 ± 1.7, with a range of 1.7-1.6 × 10(1) μg/dl. Concentrations of Pb in blood of 17.8 % of children in Riyadh were greater than 10 μg/dl, which is the CDC's level of concern.

  11. Airborne in-situ spectral characterization and concentration estimates of fluorescent organics as a function of depth

    NASA Technical Reports Server (NTRS)

    Tittle, R. A.

    1988-01-01

    The primary purpose of many in-situ airborne light scattering experiments in natural waters is to spectrally characterize the subsurface fluorescent organics and estimate their relative concentrations. This is often done by shining a laser beam into the water and monitoring its subsurface return signal. To do this with the proper interpretation, depth must be taken into account. If one disregards depth dependence when taking such estimates, both their spectral characteristics and their concentrations estimates can be rather ambiguous. A simple airborne lidar configuration is used to detect the subsurface return signal from a particular depth and wavelength. Underwater scatterometer were employed to show that in-situ subsurface organics are very sensitive to depth, but they also require the use of slow moving boats to cover large sample areas. Also, their very entry into the water disturbs the sample it is measuring. The method described is superior and simplest to any employed thus far.

  12. Differences in metal concentration by particle size in house dust and soil.

    PubMed

    Beamer, Paloma I; Elish, Christina A; Roe, Denise J; Loh, Miranda M; Layton, David W

    2012-03-01

    The majority of particles that adhere to hands are <63 μm in diameter yet risk assessments for soil remediation are typically based on soil samples sieved to <250 μm. The objective of our study was to determine if there is a significant difference in metal concentration by particle size in both house dust and soil. We obtained indoor dust and yard soil samples from 10 houses in Tucson, Arizona. All samples were sieved to <63 μm and 63 to <150 μm and analyzed for 30 elements via ICP-MS following nitric acid digestion. We conducted t-tests of the log-transformed data to assess for significant differences that were adjusted with a Bonferroni correction to account for multiple comparisons. In house dust, significant differences in concentration were observed for Be, Al, and Mo between particles sizes, with a higher concentration observed in the smaller particle sizes. Significant differences were also determined for Mg, Ca, Cr, Co, Cu, Ge, Zr, Ag, Ba, and Pb concentration in yard soil samples, with the higher concentration observed in the smaller particles size for each element. The results of this exploratory study indicate that current risk assessment practices for soil remediation may under estimate non-dietary ingestion exposure. This is of particular concern for young children who are more vulnerable to this exposure route due to their high hand mouthing frequencies. Additional studies with a greater number of samples and wider geographic distribution with different climates and soil types should be completed to determine the most relevant sampling practices for risk assessment.

  13. Differences in Metal Concentration by Particle Size in House Dust and Soil

    PubMed Central

    Elish, Christina A.; Roe, Denise J.; Loh, Miranda; Layton, David W.

    2013-01-01

    The majority of particles that adhere to hands are <63 μm in diameter yet risk assessments for soil remediation are typically based on soil samples sieved to <250 μm. The objective of our study was to determine if there is a significant difference in metal concentration by particle size in both house dust and soil. We obtained indoor dust and yard soil samples from 10 houses in Tucson, Arizona. All samples were sieved to <63 μm and 63 to <150 μm and analyzed for 30 elements via ICP-MS following nitric acid digestion. We conducted t-tests of the log-transformed data to assess for significant differences that were adjusted with a Bonferroni correction to account for multiple comparisons. In house dust significant differences in concentration were observed for Be, Al, and Mo between particles sizes, with a higher concentration observed in the smaller particles size. Significant differences were also determined for Mg, Ca, Cr, Co, Cu, Ge, Zr, Ag, Ba, and Pb concentration in yard soil samples, with the higher concentration observed in the smaller particles size for each element. The results of this exploratory study indicate that current risk assessment practices for soil remediation may under estimate non-dietary ingestion exposure. This is of particular concern for young children who are more vulnerable to this exposure route due to their high hand mouthing frequencies. Additional studies with a greater number of samples and wider geographic distribution with different climates and soil types should be completed to determine the most relevant sampling practices for risk assessment. PMID:22245917

  14. Measurement of airborne concentrations of tire and road wear particles in urban and rural areas of France, Japan, and the United States

    NASA Astrophysics Data System (ADS)

    Panko, Julie M.; Chu, Jennifer; Kreider, Marisa L.; Unice, Ken M.

    2013-06-01

    In addition to industrial facilities, fuel combustion, forest fires and dust erosion, exhaust and non-exhaust vehicle emissions are an important source of ambient air respirable particulate matter (PM10). Non-exhaust vehicle emissions are formed from wear particles of vehicle components such as brakes, clutches, chassis and tires. Although the non-exhaust particles are relatively minor contributors to the overall ambient air particulate load, reliable exposure estimates are few. In this study, a global sampling program was conducted to quantify tire and road wear particles (TRWP) in the ambient air in order to understand potential human exposures and the overall contribution of these particles to the PM10. The sampling was conducted in Europe, the United States and Japan and the sampling locations were selected to represent a variety of settings including both rural and urban core; and within each residential, commercial and recreational receptors. The air samples were analyzed using validated chemical markers for rubber polymer based on a pyrolysis technique. Results indicated that TRWP concentrations in the PM10 fraction were low with averages ranging from 0.05 to 0.70 μg m-3, representing an average PM10 contribution of 0.84%. The TRWP concentration in air was associated with traffic load and population density, but the trend was not statistically significant. Further, significant differences across days were not observed. This study provides a robust dataset to understand potential human exposures to airborne TRWP.

  15. A study of airborne chrysotile concentrations associated with handling, unpacking, and repacking boxes of automobile clutch discs.

    PubMed

    Jiang, George C T; Madl, Amy K; Ingmundson, Kelsey J; Murbach, Dana M; Fehling, Kurt A; Paustenbach, Dennis J; Finley, Brent L

    2008-06-01

    Although automotive friction products (brakes and manual clutches) historically contained chrysotile asbestos, industrial hygiene surveys and epidemiologic studies of auto mechanics have consistently shown that these workers are not at an increased risk of developing asbestos-related diseases. Airborne asbestos levels during brake repair and brake parts handling have been well-characterized, but the potential exposure to airborne asbestos fibers during the handling of clutch parts has not been examined. In this study, breathing zone samples on the lapel of a volunteer worker (n=100) and area samples at bystander (n=50), remote area (n=25), and ambient (n=9) locations collected during the stacking, unpacking, and repacking of boxes of asbestos-containing clutches, and the subsequent cleanup and clothes handling, were analyzed by phase contrast microscopy (PCM) and transmission electron microscopy (TEM). In addition, fiber morphology and size distribution was evaluated using X-ray diffraction, polarized light microscopy, and ISO analytical methods. It was observed that the (1) airborne asbestos concentrations increased with the number of boxes unpacked and repacked, (2) repetitive stacking of unopened boxes of clutches resulted in higher asbestos concentrations than unpacking and repacking the boxes of clutches, (3) cleanup and clothes handling tasks yielded very low asbestos concentrations. Fiber size and morphology analyses showed that amphibole fibers were not detected in the clutches and that the vast majority (>95%) of the airborne chrysotile fibers were less than 20 microm in length. Applying the ratio of asbestos fibers:total fibers (including non-asbestos) as determined by TEM to the PCM results, it was found that 30-min average airborne chrysotile concentrations (PCM adjusted) were 0.026+/-0.004 f/cc or 0.100+/-0.017 f/cc for a worker unpacking and repacking 1 or 2 boxes of clutches, respectively. The 30-min PCM adjusted average airborne asbestos

  16. Human Occupancy as a Source of Indoor Airborne Bacteria

    PubMed Central

    Hospodsky, Denina; Qian, Jing; Nazaroff, William W.; Yamamoto, Naomichi; Bibby, Kyle; Rismani-Yazdi, Hamid; Peccia, Jordan

    2012-01-01

    Exposure to specific airborne bacteria indoors is linked to infectious and noninfectious adverse health outcomes. However, the sources and origins of bacteria suspended in indoor air are not well understood. This study presents evidence for elevated concentrations of indoor airborne bacteria due to human occupancy, and investigates the sources of these bacteria. Samples were collected in a university classroom while occupied and when vacant. The total particle mass concentration, bacterial genome concentration, and bacterial phylogenetic populations were characterized in indoor, outdoor, and ventilation duct supply air, as well as in the dust of ventilation system filters and in floor dust. Occupancy increased the total aerosol mass and bacterial genome concentration in indoor air PM10 and PM2.5 size fractions, with an increase of nearly two orders of magnitude in airborne bacterial genome concentration in PM10. On a per mass basis, floor dust was enriched in bacterial genomes compared to airborne particles. Quantitative comparisons between bacterial populations in indoor air and potential sources suggest that resuspended floor dust is an important contributor to bacterial aerosol populations during occupancy. Experiments that controlled for resuspension from the floor implies that direct human shedding may also significantly impact the concentration of indoor airborne particles. The high content of bacteria specific to the skin, nostrils, and hair of humans found in indoor air and in floor dust indicates that floors are an important reservoir of human-associated bacteria, and that the direct particle shedding of desquamated skin cells and their subsequent resuspension strongly influenced the airborne bacteria population structure in this human-occupied environment. Inhalation exposure to microbes shed by other current or previous human occupants may occur in communal indoor environments. PMID:22529946

  17. Human occupancy as a source of indoor airborne bacteria.

    PubMed

    Hospodsky, Denina; Qian, Jing; Nazaroff, William W; Yamamoto, Naomichi; Bibby, Kyle; Rismani-Yazdi, Hamid; Peccia, Jordan

    2012-01-01

    Exposure to specific airborne bacteria indoors is linked to infectious and noninfectious adverse health outcomes. However, the sources and origins of bacteria suspended in indoor air are not well understood. This study presents evidence for elevated concentrations of indoor airborne bacteria due to human occupancy, and investigates the sources of these bacteria. Samples were collected in a university classroom while occupied and when vacant. The total particle mass concentration, bacterial genome concentration, and bacterial phylogenetic populations were characterized in indoor, outdoor, and ventilation duct supply air, as well as in the dust of ventilation system filters and in floor dust. Occupancy increased the total aerosol mass and bacterial genome concentration in indoor air PM(10) and PM(2.5) size fractions, with an increase of nearly two orders of magnitude in airborne bacterial genome concentration in PM(10). On a per mass basis, floor dust was enriched in bacterial genomes compared to airborne particles. Quantitative comparisons between bacterial populations in indoor air and potential sources suggest that resuspended floor dust is an important contributor to bacterial aerosol populations during occupancy. Experiments that controlled for resuspension from the floor implies that direct human shedding may also significantly impact the concentration of indoor airborne particles. The high content of bacteria specific to the skin, nostrils, and hair of humans found in indoor air and in floor dust indicates that floors are an important reservoir of human-associated bacteria, and that the direct particle shedding of desquamated skin cells and their subsequent resuspension strongly influenced the airborne bacteria population structure in this human-occupied environment. Inhalation exposure to microbes shed by other current or previous human occupants may occur in communal indoor environments.

  18. Temporal Variability of the Bioaerosol Background at a Subway Station: Concentration Level, Size Distribution, and Diversity of Airborne Bacteria

    PubMed Central

    Dybwad, Marius; Skogan, Gunnar

    2014-01-01

    Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 103 CFU m−3 and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents. PMID:24162566

  19. Airborne concentrations of benzene and mineral spirits (stoddard solvent) during cleaning of a locomotive generator and traction motor.

    PubMed

    Madl, Amy K; Paustenbach, Dennis J

    2002-12-13

    Mineral spirits (also called Stoddard solvent), a petroleum distillate, is often used as a degreaser or an industrial cleaning agent. Although several studies measured airborne concentrations of mineral spirits in various occupational settings, none have characterized the airborne concentrations of benzene from use of mineral spirits. Recent case reports have suggested that benzene, as a contaminant in mineral spirits, might be responsible for adverse health effects. Because some claims of health effects in the railroad industry have been attributed to potential historical exposures to mineral spirits and little information is available regarding air concentrations in this type of occupational setting, a simulation study was conducted to quantitate historical exposures a railroad worker might have experienced while spraying mineral spirits on locomotive engine parts in the 1970s. To quantitate potential historical exposures, worker tasks were simulated under worst-case exposure conditions by spraying minerals spirits on a locomotive generator and traction motor. The results of both generator and traction motor cleaning events produced concentrations of mineral spirits ranging from 34 to 221 ppm and an average 1-h concentration of 121 ppm, whereas benzene concentrations associated with the spraying and drying tasks were less than the limit of detection (0.002-0.006 ppm). Results indicate that a railroad worker who cleaned a locomotive traction motor and generator with mineral spirits for 2 h each workday under worst-case exposure conditions would be exposed to an 8-h time-weighted average (based on lapel measurements) of 30.4 ppm airborne mineral spirits. On the basis of the conditions under which these concentrations were obtained, the results should be the reasonable maximum values that can be achieved in a modern-era (post-1970) workplace in the United States.

  20. Desert Dust Outbreaks in Southern Europe: Contribution to Daily PM10 Concentrations and Short-Term Associations with Mortality and Hospital Admissions

    PubMed Central

    Stafoggia, Massimo; Zauli-Sajani, Stefano; Pey, Jorge; Samoli, Evangelia; Alessandrini, Ester; Basagaña, Xavier; Cernigliaro, Achille; Chiusolo, Monica; Demaria, Moreno; Díaz, Julio; Faustini, Annunziata; Katsouyanni, Klea; Kelessis, Apostolos G.; Linares, Cristina; Marchesi, Stefano; Medina, Sylvia; Pandolfi, Paolo; Pérez, Noemí; Querol, Xavier; Randi, Giorgia; Ranzi, Andrea; Tobias, Aurelio; Forastiere, Francesco

    2015-01-01

    Background: Evidence on the association between short-term exposure to desert dust and health outcomes is controversial. Objectives: We aimed to estimate the short-term effects of particulate matter ≤ 10 μm (PM10) on mortality and hospital admissions in 13 Southern European cities, distinguishing between PM10 originating from the desert and from other sources. Methods: We identified desert dust advection days in multiple Mediterranean areas for 2001–2010 by combining modeling tools, back-trajectories, and satellite data. For each advection day, we estimated PM10 concentrations originating from desert, and computed PM10 from other sources by difference. We fitted city-specific Poisson regression models to estimate the association between PM from different sources (desert and non-desert) and daily mortality and emergency hospitalizations. Finally, we pooled city-specific results in a random-effects meta-analysis. Results: On average, 15% of days were affected by desert dust at ground level (desert PM10 > 0 μg/m3). Most episodes occurred in spring–summer, with increasing gradient of both frequency and intensity north–south and west–east of the Mediterranean basin. We found significant associations of both PM10 concentrations with mortality. Increases of 10 μg/m3 in non-desert and desert PM10 (lag 0–1 days) were associated with increases in natural mortality of 0.55% (95% CI: 0.24, 0.87%) and 0.65% (95% CI: 0.24, 1.06%), respectively. Similar associations were estimated for cardio-respiratory mortality and hospital admissions. Conclusions: PM10 originating from the desert was positively associated with mortality and hospitalizations in Southern Europe. Policy measures should aim at reducing population exposure to anthropogenic airborne particles even in areas with large contribution from desert dust advections. Citation: Stafoggia M, Zauli-Sajani S, Pey J, Samoli E, Alessandrini E, Basagaña X, Cernigliaro A, Chiusolo M, Demaria M, Díaz J, Faustini A

  1. 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.

  2. Variability in the Correlation between Asian Dust Storms and Chlorophyll a Concentration from the North to Equatorial Pacific

    PubMed Central

    Tan, Sai-Chun; Yao, Xiaohong; Gao, Hui-Wang; Shi, Guang-Yu; Yue, Xu

    2013-01-01

    A long-term record of Asian dust storms showed seven high-occurrence-frequency centers in China. The intrusion of Asian dust into the downwind seas, including the China seas, the Sea of Japan, the subarctic North Pacific, the North Pacific subtropical gyre, and the western and eastern Equatorial Pacific, has been shown to add nutrients to ocean ecosystems and enhance their biological activities. To explore the relationship between the transported dust from various sources to the six seas and oceanic biological activities with different nutrient conditions, the correlation between monthly chlorophyll a concentration in each sea and monthly dust storm occurrence frequencies reaching the sea during 1997–2007 was examined in this study. No correlations were observed between dust and chlorophyll a concentration in the <50 m China seas because atmospheric deposition is commonly believed to exert less impact on coastal seas. Significant correlations existed between dust sources and many sea areas, suggesting a link between dust and chlorophyll a concentration in those seas. However, the correlation coefficients were highly variable. In general, the correlation coefficients (0.54–0.63) for the Sea of Japan were highest, except for that between the subarctic Pacific and the Taklimakan Desert, where it was as high as 0.7. For the >50 m China seas and the North Pacific subtropical gyre, the correlation coefficients were in the range 0.32–0.57. The correlation coefficients for the western and eastern Equatorial Pacific were relatively low (<0.36). These correlation coefficients were further interpreted in terms of the geographical distributions of dust sources, the transport pathways, the dust deposition, the nutrient conditions of oceans, and the probability of dust storms reaching the seas. PMID:23460892

  3. Fungal Spore Concentrations and Ergosterol Content in Aerosol Samples in the Caribbean During African Dust Events

    NASA Astrophysics Data System (ADS)

    Santos-Figueroa, G.; Bolaños-Rosero, B.; Mayol-Bracero, O. L.

    2015-12-01

    Fungal spores are a major component of primary biogenic aerosol particles that are emitted to the atmosphere, are ubiquitous, and play an important role in the chemistry and physics of the atmosphere, climate, and public health. Every year, during summer months, African dust (AD) particles are transported to the Caribbean region causing an increase in the concentrations of particulate matter in the atmosphere. AD is one of the most important natural sources of mineral particulate matter at the global scale, and many investigations suggest that it has the ability to transport dust-associated biological particles through long distances. The relationship between AD incursions and the concentration of fungal spores in the Caribbean region is poorly understood. In order to investigate the effects of AD incursions on fungal spore's emissions, fungal spore concentrations were monitored using a Burkard spore trap at the tropical montane cloud forest of Pico del Este at El Yunque National Forest, Puerto Rico. The presence of AD was supported with satellite images of aerosol optical thickness, and with the results from the air masses backward trajectories calculated with the NOAA HYSPLIT model. Basidiospores and Ascospores comprised the major components of the total spore's concentrations, up to a maximum of 98%, during both AD incursions and background days. A considerably decrease in the concentration of fungal spores during AD events was observed. Ergosterol, biomarker for measuring fungal biomass, concentrations were determined in aerosols that were sampled at a marine site, Cabezas de San Juan Nature Reserve, in Fajardo Puerto Rico, and at an urban site, Facundo Bueso building at the University of Puerto Rico. Additional efforts to understand the relationship between the arrival of AD to the Caribbean and a decrease in spore's concentrations are needed in order to investigate changes in local spore's vs the contribution of long-range spores transported within the AD.

  4. Improving Simulations of Fine Dust Surface Concentrations over the Western United States by Optimizing the Particle Size Distribution

    SciTech Connect

    Zhang, Li; Kok, Jasper F.; Henze, Daven; Li, Qinbin; Zhao, Chun

    2013-06-28

    To improve estimates of remote contributions of dust to fine particulate matter (PM2.5) in the western United States, new dust particle size distributions (PSDs) based upon scale-invariant fragmentation theory (Kok_PSD) with constraints from in situ measurements (IMP_PSD) are implemented in a chemical transport model (GEOS-Chem). Compared to initial simulations, this leads to reductions in the mass of emitted dust particles with radii <1.8 mm by 40%-60%. Consequently, the root-mean-square error in simulated fine dust concentrations compared to springtime surface observations in the western United States is reduced by 67%-81%. The ratio of simulated fine to coarse PM mass is also improved, which is not achievable by reductions in total dust emissions. The IMP_PSD best represents the PSD of dust transported from remote sources and reduces modeled PM2.5 concentrations up to 5 mg/m3 over the western United States, which is important when considering sources contributing to nonattainment of air quality standards. Citation: Zhang, L., J. F. Kok, D. K. Henze, Q. Li, and C. Zhao (2013), Improving simulations of fine dust surface concentrations over the western United States by optimizing the particle size distribution, Geophys. Res. Lett., 40, 3270-3275, doi:10.1002/grl.50591.

  5. Estimation of collection efficiency depended on feed particle concentration for axial flow cyclone dust collector

    NASA Astrophysics Data System (ADS)

    Ogawa, Akira

    1999-09-01

    A cyclone dust collector is applied in many industries. Especially the axial flow cyclone is the most simple construction and it keeps high reliability for maintenance. On the other hand, the collection efficiency of the cyclone depends not only on the inlet gas velocity but also on the feed particle concentration. The collection efficiency increases with increasing feed particle concentration. However until now the problem of how to estimate the collection efficiency depended on the feed particle concentration is remained except the investigation by Muschelknautz & Brunner[6]. Therefore in this paper one of the estimate method for the collection efficiency of the axial flow cyclones is proposed. The application to the geometrically similar type of cyclone of the body diameters D 1=30, 50, 69 and 99 mm showed in good agreement with the experimental results of the collection efficiencies which were described in detail in the paper by Ogawa & Sugiyama[8].

  6. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    PubMed

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV.

  7. The effects of a newsletter on bedding control on house dust mite allergen concentrations in childcare centers in Korea

    PubMed Central

    Kim, Jeonghoon; Jeong, Kyoung Yong; Kwon, Ho-Jang; Yang, Heasuk; Yum, Hye Yung; Lee, Seon Ah; Kim, Chae-Bong; Kim, Hyunjung; Lim, Wan Ryung; Hong, Soyoung; Kim, Kyoosang

    2015-01-01

    Objectives Bedding in childcare centers (CCCs) can hold house dust mite (HDM) allergens. This study examined whether HDM allergen levels can be reduced through the distribution of an educational newsletter on bedding control to parents of CCC children in Korea. Methods All 38 CCCs were measured for Der 1 (sum of Der f 1 and Der p 1) concentrations on classroom floors and bedding before the intervention. Educational newsletters on children’s bedding control were sent to 21 CCCs by mail, and teachers were asked to distribute the newsletters to the parents of the children (intervention group). The remaining 17 CCCs were not sent newsletters (control group). The measurement of Der 1 concentrations in 38 CCCs was repeated after the intervention. Dust samples were collected with a vacuum cleaner and analyzed using enzyme-linked immunosorbent assay methods. Results The Der 1 concentrations on the bedding were significantly higher than those on the floors in 38 CCCs at baseline (p<0.05). Although changes of the Der 1 concentrations for the control group (n=17) were not significant, Der 1 concentrations for the intervention group (n=21) decreased significantly from 2077.9 ng/g dust to 963.5 ng/g dust on the floors and from 3683.9 ng/g dust to 610.4 ng/g dust on bedding (p<0.05). Conclusions The distribution of educational newsletters on bedding control to parents may be an effective means of controlling HDMs in CCCs. PMID:26602559

  8. Effect of manual feeding on the level of farmer's exposure to airborne contaminants in the confinement nursery pig house.

    PubMed

    Kim, Ki-Youn; Ko, Han-Jong; Kim, Hyeon-Tae; Kim, Chi-Nyon; Kim, Yoon-Shin; Roh, Young-Man

    2008-04-01

    The objective of the study is to demonstrate an effect of manual feeding on the level of farmer's exposure to airborne contaminants in the confinement nursery pig house. The levels of all the airborne contaminants besides respirable dust, total airborne fungi and ammonia were significantly higher in the treated nursery pig house with feeding than the control nursery pig house without feeding. Although there is no significant difference in respirable dust and total airborne fungi between the treatment and the control, their concentrations in the treated nursery pig house were also higher than the control nursery pig house. The result that the level of ammonia in the treated nursery pig house is lower than the control nursery pig house would be reasoned by the mechanism of ammonia generation in the pig house and adsorption property of ammonia to dust particles. In conclusion, manual feeding by farmer increased the exposure level of airborne contaminants compared to no feeding activity.

  9. A coupled model of the airborne and surface concentration of radionuclides considering the resuspension-deposition process

    NASA Astrophysics Data System (ADS)

    Ichige, Hiroyuki; Hatano, Yuko; Onda, Yuichi

    2014-05-01

    We propose a new model of estimating the long-term behavior of both the airborne and the surface concentrations of radionuclides in the vicinity of 30 km of Fukushima plant. Our model consists of the following simultaneous equations: δC- = viδC-+ ΛupS - ΛdownC - ΛdecC (1) δt δxi δS- = - Λ S + Λ C - Λ S, (2) δt up down env where C is the airborne concentration of a specific nuclide, S the surface concentration, the suffix i is 1 or 2 (2 dimensional), v the effective wind velocity which migrates the radionuclides in the air, Λup the rate constant of resuspension process, Λdown of deposition process, Λdec the decay constant, and Λenv is the rate constant of the surface concentration decrease due to environmental factors such as runoff, washoff, infiltrations, and the vegetation effects. These equations are based on our former study (Hatano and Hatano, 1997; Hatano et al., 1998) which successfully reproduce the long-term decrease of airborne concentration of the Chernobyl data such as Cs-137, Cs-134, Ce-144, and Ru-106 over nearly a decade. The first equation of the present study is essentially the same as our previous studies, besides that we added a new term for deposition. The second equation is newly added in the present study which describes the behavior of the surface concentration. In Fukushima case, we found that the radiation risk is much higher than the airborne concentration. That is why we add the second equation. Since the new model requires parameter values of Λs we need to estimate these values from actual data. In order to do so, we apply the method of inverse problem and thereby estimate the values. We also do the spectral analysis of the dose rate (mainly from Cs-137, -134) and study if it is possible to estimate the resuspended amount from the ground surface.

  10. Dust radiative forcing in snow of the Upper Colorado River Basin: 1. A 6 year record of energy balance, radiation, and dust concentrations

    NASA Astrophysics Data System (ADS)

    Painter, Thomas H.; Skiles, S. Mckenzie; Deems, Jeffrey S.; Bryant, Ann C.; Landry, Christopher C.

    2012-07-01

    Dust in snow accelerates snowmelt through its direct reduction of snow albedo and its further indirect reduction of albedo by accelerating the growth of snow grains. Since the westward expansion of the United States that began in the mid-19th century, the mountain snow cover of the Colorado River Basin has been subject to five-fold greater dust loading, largely from the Colorado Plateau and Great Basin. Radiative forcing of snowmelt by dust is not captured by conventional micrometeorological measurements, and must be monitored by a more comprehensive suite of radiation instruments. Here we present a 6 year record of energy balance and detailed radiation measurements in the Senator Beck Basin Study Area, San Juan Mountains, Colorado, USA. Data include broadband irradiance, filtered irradiance, broadband reflected flux, filtered reflected flux, broadband and visible albedo, longwave irradiance, wind speed, relative humidity, and air temperatures. The gradient of the snow surface is monitored weekly and used to correct albedo measurements for geometric effects. The snow is sampled weekly for dust concentrations in plots immediately adjacent to each tower over the melt season. Broadband albedo in the last weeks of snow cover ranged from 0.33 to 0.55 across the 6 years and two sites. Total end of year dust concentration in the top 3 cm of the snow column ranged from 0.23 mg g-1 to 4.16 mg g-1. These measurements enable monitoring and modeling of dust and climate-driven snowmelt forcings in the Upper Colorado River Basin.

  11. 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.

  12. Assessment of chlorophyll-a concentration in the Gulf of Riga using hyperspectral airborne and simulated Sentinel-3 OLCI data

    NASA Astrophysics Data System (ADS)

    Jakovels, Dainis; Brauns, Agris; Filipovs, Jevgenijs; Taskovs, Juris; Fedorovicha, Dagnija; Paavel, Birgot; Ligi, Martin; Kutser, Tiit

    2016-08-01

    Remote sensing has proved to be an accurate and reliable tool in clear water environments like oceans or the Mediterranean Sea. However, the current algorithms and methods usually fail on optically complex waters like coastal and inland waters. The whole Baltic Sea can be considered as optically complex coastal waters. Remote assessment of water quality parameters (eg., chlorophyll-a concentration) is of interest for monitoring of marine environment, but hasn't been used as a routine approach in Latvia. In this study, two simultaneous hyperspectral airborne data and in situ measurement campaigns were performed in the Gulf of Riga near the River Daugava mouth in summer 2015 to simulate Sentinel-3 data and test existing algorithms for retrieval of Level 2 Water products. Comparison of historical data showed poor overall correlation between in situ measurements and MERIS chlorophyll-a data products. Better correlation between spectral chl-a data products and in situ water sampling measurements was achieved during simultaneous airborne and field campaign resulting in R2 up to 0.94 for field spectral data, R2 of 0.78 for airborne data. Test of all two band ratio combinations showed that R2 could be improved from 0.63 to 0.94 for hyperspectral airborne data choosing 712 and 728 nm bands instead of 709 and 666 nm, and R2 could be improved from 0.61 to 0.83 for simulated Sentinel-3 OLCI data choosing Oa10 and Oa8 bands instead of Oa11 and Oa8. Repeated campaigns are planned during spring and summer blooms 2016 in the Gulf of Riga to get larger data set for validation and evaluate repeatability. The main challenges remain to acquire as good data as possible within rapidly changing environment and often cloudy weather conditions.

  13. Exposure to Hexabromocyclododecanes (HBCDs) via Dust Ingestion, but Not Diet, Correlates with Concentrations in Human Serum: Preliminary Results

    PubMed Central

    Roosens, Laurence; Abdallah, Mohamed Abou-Elwafa; Harrad, Stuart; Neels, Hugo; Covaci, Adrian

    2009-01-01

    Background Hexabromocyclododecane (HBCD) is a high-production-volume chemical used as flame retardant in polystyrene insulation and textiles. Because it is not chemically bound to the polymer, HBCD can migrate into the environment, contaminating indoor dust and foodstuff. Objectives We examined for the first time the relationship between combined exposure to three HBCD isomers (∑HBCDs) via ingestion of food (duplicate diets) and indoor dust and HBCD concentrations in serum for 16 Belgian adults (20–25 years of age). We also determined the chiral signatures of HBCDs to advance understanding of source-to-human enantioselective degradation and/or metabolism. Methods Concentrations and chiral signatures of α-, β-, and γ-HBCD in duplicate diets, dust, and serum were measured by liquid chromatography/tandem mass spectrometry. Results Dietary intakes of ∑HBCDs were 1.2–20 ng/day (average, 7.2 ng/day), whereas those estimated under average (20 mg dust/day) and high (50 mg dust/day) dust ingestion scenarios were 1.1–15 ng/day (average intake, 3.2 ng/day) and 2.8–38 ng/day (average intake, 8.0 ng/day), respectively. Concentrations of ∑HBCDs measured in blood serum were < 0.5 to 11 ng/g lipid weight (lw) (average, 2.9 ng/g lw). γ-HBCD dominated in food, whereas α-HBCD dominated in dust and was the sole isomer in serum. Although exposure via dust ingestion correlated significantly (p < 0.01) with concentrations in serum, no such correlation was evident with dietary exposure (p > 0.1). Although no enantioselective enrichment was detected in either dust or diet, substantial enrichment of (−)α-HBCD was observed in serum. Conclusions Serum concentrations of HBCDs were correlated with the exposure via dust, but not via dietary ingestion. The enrichment of the (−)α-HBCD enantiomer in humans appears to be due to in vivo enantioselective metabolism/excretion rather than ingestion of dust or diet. PMID:20049121

  14. House dust in seven Danish offices

    NASA Astrophysics Data System (ADS)

    Mølhave, L.; Schneider, T.; Kjærgaard, S. K.; Larsen, L.; Norn, S.; Jørgensen, O.

    Floor dust from Danish offices was collected and analyzed. The dust was to be used in an exposure experiment. The dust was analyzed to show the composition of the dust which can be a source of airborne dust indoors. About 11 kg of dust from vacuum cleaner bags from seven Danish office buildings with about 1047 occupants (12 751 m 2) was processed according to a standardized procedure yielding 5.5 kg of processed bulk dust. The bulk dust contained 130.000-160.000 CFU g -1 microorganisms and 71.000-90.000 CFU g -1 microfungi. The content of culturable microfungi was 65-123 CFU 30 g -1 dust. The content of endotoxins ranged from 5.06-7.24 EU g -1 (1.45 ng g -1 to 1.01 ng g -1). Allergens (ng g -1) were from 147-159 (Mite), 395-746 (dog) and 103-330 (cat). The macro molecular organic compounds (the MOD-content) varied from 7.8-9.8 mg g -1. The threshold of release of histamine from basophil leukocytes provoked by the bulk dust was between 0.3 and 1.0 mg ml -1. The water content was 2% (WGT) and the organic fraction 33%. 6.5-5.9% (dry) was water soluble. The fiber content was less than 0.2-1.5% (WGT) and the desorbable VOCs was 176-319 μg g -1. Most of the VOC were aldehydes. However, softeners for plastic (DBP and DEHP) were present. The chemical composition includes human and animal skin fragments, paper fibers, glass wool, wood and textilefibers and inorganic and metal particles. The sizes ranged from 0.001-1 mm and the average specific density was 1.0 g m -3. The bulk dust was resuspended and injected into an exposure chamber. The airborne dust was sampled and analyzed to illustrate the exposures that can result from sedimented dirt and dust. The airborne dust resulting from the bulk dust reached concentrations ranging from 0.26-0.75 mg m -3 in average contained 300-170 CFU m -3. The organic fraction was from 55-70% and the water content about 2.5% (WGT). The content of the dust was compared to the similar results reported in the literature and its toxic potency is

  15. Comparison of surface-coal-mine respirable dust concentrations measured with MRE and personal gravimetric sampling equipment

    SciTech Connect

    Alvarez, J.J.; Tomb, T.F.; Gadomski, R.R.; Custer, J.L.

    1980-01-01

    All coal mine respirable dust concentrations measured with approved personal respirable dust sampling instruments are converted to equivalent MRE sampler concentrations by multiplying by the factor 1.38. This conversion factor was determined from comparison measurements made in underground coal mine environments. This report describes the results of the Mine Safety and Health Administration's (MSHA) sampling of surface mining operations to determine if 1.38 is a valid factor for converting surface coal mine dust samples collected with approved personal samplers to equivalent MRE concentrations. Comparative measurements were obtained with the MRE and personal gravimetric dust samplers at a variety of surface mining operations and coal preparation plants. Regression analysis was used to derive a relationship between measurements obtained with the MRE and personal respirable dust samplers. The factor derived for surface measurements was within 9 percent of that derived for underground measurements. It was concluded that 1.38 is the most applicable factor to use for converting personal respirable dust measurements to equivalent MRE measurements.

  16. Integration for Airborne Dust Prediction Systems and Vegetation Phenology to Track Pollen for Asthma Alerts in Public Health Decision Support Systems

    NASA Technical Reports Server (NTRS)

    Luvall, J. C.; Sprigg, W. A.; Nickovic, S.; Huete, A.; Budge, A.; Flowers, L.

    2008-01-01

    The objective of the program is to assess the feasibility of combining a dust transport model with MODIS derived phenology to study pollen transport for integration with a public health decision support system. The use of pollen information has specifically be identified as a critical need by the New Mexico State Health department for inclusion in the Environmental Public Health Tracking (EPHT) program. Material and methods: Pollen can be transported great distances. Local observations of plan phenology may be consistent with the timing and source of pollen collected by pollen sampling instruments. The Dust REgional Atmospheric Model (DREAM) is an integrated modeling system designed to accurately describe the dust cycle in the atmosphere. The dust modules of the entire system incorporate the state of the art parameterization of all the major phases of the atmospheric dust life such as production, diffusion, advection, and removal. These modules also include effects of the particles size distribution on aerosol dispersion. The model was modified to use pollen sources instead of dust. Pollen release was estimated based on satellite-derived phenology of key plan species and vegetation communities. The MODIS surface reflectance product (MOD09) provided information on the start of the plant growing season, growth stage, and pollen release. The resulting deterministic model is useful for predicting and simulating pollen emission and downwind concentration to study details of phenology and meteorology and their dependencies. The proposed linkage in this project provided critical information on the location timing and modeled transport of pollen directly to the EPHT> This information is useful to support the centers for disease control and prevention (CDC)'s National EPHT and the state of New Mexico environmental public health decision support for asthma and allergies alerts.

  17. Correlation between airborne Olea europaea pollen concentrations and levels of the major allergen Ole e 1 in Córdoba, Spain, 2012-2014

    NASA Astrophysics Data System (ADS)

    Plaza, M. P.; Alcázar, P.; Galán, C.

    2016-12-01

    Olea europaea L. pollen is the second-largest cause of pollinosis in the southern Iberian Peninsula. Airborne-pollen monitoring networks provide essential data on pollen dynamics over a given study area. Recent research, however, has shown that airborne pollen levels alone do not always provide a clear indicator of actual exposure to aeroallergens. This study sought to evaluate correlations between airborne concentrations of olive pollen and Ole e 1 allergen levels in Córdoba (southern Spain), in order to determine whether atmospheric pollen concentrations alone are sufficient to chart changes in hay fever symptoms. The influence of major weather-related variables on local airborne pollen and allergen levels was also examined. Monitoring was carried out from 2012 to 2014. Pollen sampling was performed using a Hirst-type sampler, following the protocol recommended by the Spanish Aerobiology Network. A multi-vial cyclone sampler was used to collect aeroallergens, and allergenic particles were quantified by ELISA assay. Significant positive correlations were found between daily airborne allergen levels and atmospheric pollen concentrations, although there were occasions when allergen was detected before and after the pollen season and in the absence of airborne pollen. The correlation between the two was irregular, and pollen potency displayed year-on-year variations and did not necessarily match pollen-season-intensity.

  18. Airborne Particulate Matter in Two Multi-Family Green Buildings: Concentrations and Effect of Ventilation and Occupant Behavior

    PubMed Central

    Patton, Allison P.; Calderon, Leonardo; Xiong, Youyou; Wang, Zuocheng; Senick, Jennifer; Sorensen Allacci, MaryAnn; Plotnik, Deborah; Wener, Richard; Andrews, Clinton J.; Krogmann, Uta; Mainelis, Gediminas

    2016-01-01

    There are limited data on air quality parameters, including airborne particulate matter (PM) in residential green buildings, which are increasing in prevalence. Exposure to PM is associated with cardiovascular and pulmonary diseases, and since Americans spend almost 90% of their time indoors, residential exposures may substantially contribute to overall airborne PM exposure. Our objectives were to: (1) measure various PM fractions longitudinally in apartments in multi-family green buildings with natural (Building E) and mechanical (Building L) ventilation; (2) compare indoor and outdoor PM mass concentrations and their ratios (I/O) in these buildings, taking into account the effects of occupant behavior; and (3) evaluate the effect of green building designs and operations on indoor PM. We evaluated effects of ventilation, occupant behaviors, and overall building design on PM mass concentrations and I/O. Median PMTOTAL was higher in Building E (56 µg/m3) than in Building L (37 µg/m3); I/O was higher in Building E (1.3–2.0) than in Building L (0.5–0.8) for all particle size fractions. Our data show that the building design and occupant behaviors that either produce or dilute indoor PM (e.g., ventilation systems, combustion sources, and window operation) are important factors affecting residents’ exposure to PM in residential green buildings. PMID:26805862

  19. Airborne Particulate Matter in Two Multi-Family Green Buildings: Concentrations and Effect of Ventilation and Occupant Behavior.

    PubMed

    Patton, Allison P; Calderon, Leonardo; Xiong, Youyou; Wang, Zuocheng; Senick, Jennifer; Sorensen Allacci, MaryAnn; Plotnik, Deborah; Wener, Richard; Andrews, Clinton J; Krogmann, Uta; Mainelis, Gediminas

    2016-01-20

    There are limited data on air quality parameters, including airborne particulate matter (PM) in residential green buildings, which are increasing in prevalence. Exposure to PM is associated with cardiovascular and pulmonary diseases, and since Americans spend almost 90% of their time indoors, residential exposures may substantially contribute to overall airborne PM exposure. Our objectives were to: (1) measure various PM fractions longitudinally in apartments in multi-family green buildings with natural (Building E) and mechanical (Building L) ventilation; (2) compare indoor and outdoor PM mass concentrations and their ratios (I/O) in these buildings, taking into account the effects of occupant behavior; and (3) evaluate the effect of green building designs and operations on indoor PM. We evaluated effects of ventilation, occupant behaviors, and overall building design on PM mass concentrations and I/O. Median PMTOTAL was higher in Building E (56 µg/m³) than in Building L (37 µg/m³); I/O was higher in Building E (1.3-2.0) than in Building L (0.5-0.8) for all particle size fractions. Our data show that the building design and occupant behaviors that either produce or dilute indoor PM (e.g., ventilation systems, combustion sources, and window operation) are important factors affecting residents' exposure to PM in residential green buildings.

  20. Airborne concentrations of trivalent and hexavalent chromium from contaminated soils at unpaved and partially paved commercial/industrial sites

    SciTech Connect

    Falerios, M.; Schild, K. ); Sheehan, P.; Paustenbach, D.J. )

    1992-01-01

    This method described was used to quantify airborne Cr(VI) levels at both indoor and outdoor locations at 21 sites in Hudson County, New Jersey which have soils containing chromite ore processing residue. Of the 21 sites evaluated, nine were unpaved or partially paved industrial/commercial sites or roadways with a moderate to high level of heavy truck traffic. Most of the remainder were commercial facilities with partially paved or unpaved parking lots and only light vehicle traffic. In addition, 15 residential sites in the area which do not have contaminated soil were sampled to characterized background levels of Cr(VI). The overall arithmetic mean values for indoor and outdoor Cr(VI) in total suspended particulates at the 12 industrial sites were 3.0 ng/m{sup 3} and 9.9ng/m{sup 3}, respectively. The indoor Cr(VI) concentrations measured at the 15 residential sites ranged from 0.38 to 3.3 ng/m{sup 3}. Airborne Cr(VI) levels outdoors at sites with chromite ore residue appear to be primarily influenced by the level of local vehicle traffic. Measured outdoor concentrations at sites with light vehicle traffic were generally low, within the range of levels measured indoors at the residential sites, and not strongly influenced by Cr(VI) concentrations in surface soils. At sites with a high rate of vehicle traffic, outdoor Cr(VI) concentrations exceeded background levels only on days when surface soils were dry. The average concentrations measured at these sites were more than 5,000-times lower than the current occupational exposure limit for Cr(VI) (TLV = 0.05 mg/m{sup 3}).

  1. 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.

  2. Evaluation of ultraviolet germicidal irradiation in reducing the airborne cultural bacteria concentrations in an elementary school in the Midwestern United States.

    PubMed

    Su, Chunxiao; Lau, Josephine; Gibbs, Shawn G

    2015-05-01

    This article describes a casestudythe authors conducted in an elementary school in the Midwest. The objective was to evaluate the performance of ultraviolet germicidal irradiation (UGVI) to reduce the bioaerosol concentration in a classroom. Two fourth grade classrooms with the same dimensions were studied. One classroom was designated as the UVGI group and the other as the control group. Two-stage Tisch culturable impactors were utilized for collecting airborne bacteria with monthly samples collected from October 2012 to January 2013. Nonparametric methods were applied and p-values smaller than .05 were deemed significant. The concentrations of airborne cultural bacteria with a smaller size (1-8 pm) and the total bacterial concentrations from the UVGI classroom were significantly lower than those of the control room in three of four sampling months. These results could provide the preliminary results necessary to determine the effectiveness of upper-room UVGI in reducing the concentration of airborne cultural bacteria in classrooms and other buildings.

  3. Quantitative detection of mass concentration of sand-dust storms via wind-profiling radar and analysis of Z-M relationship

    NASA Astrophysics Data System (ADS)

    Wang, Minzhong; Ming, Hu; Ruan, Zheng; Gao, Lianhui; Yang, Di

    2016-12-01

    With the aim to achieve quantitative monitoring of sand-dust storms in real time, wind-profiling radar is applied to monitor and study the process of four sand-dust storms in the Tazhong area of the Taklimakan Desert. Through evaluation and analysis of the spatial-temporal distribution of reflectivity factor, it is found that reflectivity factor ranges from 2 to 18 dBz under sand-dust storm weather. Using echo power spectrum of radar vertical beams, sand-dust particle spectrum and sand-dust mass concentration at the altitude of 600 ˜ 1500 m are retrieved. This study shows that sand-dust mass concentration reaches 700 μg/m3 under blowing sand weather, 2000 μg/m3 under sand-dust storm weather, and 400 μg/m3 under floating dust weather. The following equations are established to represent the relationship between the reflectivity factor and sand-dust mass concentration: Z = 20713.5 M 0.995 under floating dust weather, Z = 22988.3 M 1.006 under blowing sand weather, and Z = 24584.2 M 1.013 under sand-dust storm weather. The retrieval results from this paper are almost consistent with previous monitoring results achieved by former researchers; thus, it is implied that wind-profiling radar can be used as a new reference device to quantitatively monitor sand-dust storms.

  4. Assessment of EOS Aqua AMSR-E Arctic Sea Ice Concentrations using Landsat-7 and Airborne Microwave Imagery

    NASA Technical Reports Server (NTRS)

    Cavalieri, Donald J.; Markus, Thorsten; Hall, Dorothy K.; Gasiewski, Albin J.; Klein, Marian; Ivanoff, Alvaro

    2006-01-01

    An assessment of Advanced Microwave Scanning Radiometer Earth Observing System (AMSR-E) sea ice concentrations under winter conditions using ice concentrations derived from Landsat-7 Enhanced Thematic Mapper Plus (ETM+) imagery obtained during the March 2003 Arctic sea ice validation field campaign is presented. The National Oceanic and Atmospheric Administration Environmental Technology Laboratory's Airborne Polarimetric Scanning Radiometer Measurements, which were made from the National Aeronautics and Space Administration P 3B aircraft during the campaign, were used primarily as a diagnostic tool to understand the comparative results and to suggest improvements to the AMSR-E ice concentration algorithm. Based on the AMSR-E/ETM+ comparisons, a good overall agreement with little bias (approx. 1%) for areas of first year and young sea ice was found. Areas of new ice production result in a negative bias of about 5% in the AMSR-E ice concentration retrievals, with a root mean square error of 8%. Some areas of deep snow also resulted in an underestimate of the ice concentration (approx. 10%). For all ice types combined and for the full range of ice concentrations, the bias ranged from 0% to 3%, and the rms errors ranged from 1% to 7%, depending on the region. The new-ice and deep-snow biases are expected to be reduced through an adjustment of the new-ice and ice-type C algorithm tie points.

  5. Sensitivities of five alpha continuous air monitors for detection of airborne {sup 239}Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  6. Sensitivities of five alpha continuous air monitors for detection of airborne sup 239 Pu

    SciTech Connect

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  7. Vertically-resolved profiles of mass concentrations and particle backscatter coefficients of Asian dust plumes derived from lidar observations of silicon dioxide.

    PubMed

    Noh, Youngmin; Müller, Detlef; Shin, Sung-Kyun; Shin, Dongho; Kim, Young J

    2016-01-01

    This study presents a method to retrieve vertically-resolved profiles of dust mass concentrations by analyzing Raman lidar signals of silicon dioxide (quartz) at 546nm. The observed particle plumes consisted of mixtures of East Asian dust with anthropogenic pollution. Our method for the first time allows for extracting the contribution of the aerosol component "pure dust" contained in the aerosol type "polluted dust". We also propose a method that uses OPAC (Optical Properties of Aerosols and Clouds) and the mass concentrations profiles of dust in order to derive profiles of backscatter coefficients of pure dust in mixed dust/pollution plumes. The mass concentration of silicon dioxide (quartz) in the atmosphere can be estimated from the backscatter coefficient of quartz. The mass concentration of dust is estimated by the weight percentage (38-77%) of mineral quartz in Asian dust. The retrieved dust mass concentrations are classified into water soluble, nucleation, accumulation, mineral-transported and coarse mode according to OPAC. The mass mixing ratio of 0.018, 0.033, 0.747, 0.130 and 0.072, respectively, is used. Dust extinction coefficients at 550nm were calculated by using OPAC and prescribed number concentrations for each of the 5 components. Dust backscatter coefficients were calculated from the dust extinction coefficients on the basis of a lidar ratio of 45±3sr at 532nm. We present results of quartz-Raman measurements carried out on the campus of the Gwangju Institute of Science and Technology (35.10°N, 126.53°E) on 15, 16, and 21 March 2010.

  8. Airborne black carbon concentrations over an urban region in western India-temporal variability, effects of meteorology, and source regions.

    PubMed

    Bapna, Mukund; Sunder Raman, Ramya; Ramachandran, S; Rajesh, T A

    2013-03-01

    This study characterizes over 5 years of high time resolution (5 min), airborne black carbon (BC) concentrations (July 2003 to December 2008) measured over Ahmedabad, an urban region in western India. The data were used to obtain different time averages of BC concentrations, and these averages were then used to assess the diurnal, seasonal, and annual variability of BC over the study region. Assessment of diurnal variations revealed a strong association between BC concentrations and vehicular traffic. Peaks in BC concentration were co-incident with the morning (0730 to 0830, LST) and late evening (1930 to 2030, LST) rush hour traffic. Additionally, diurnal variability in BC concentrations during major festivals (Diwali and Dushera during the months of October/November) revealed an increase in BC concentrations due to fireworks displays. Maximum half hourly BC concentrations during the festival days were as high as 79.8 μg m(-3). However, the high concentrations rapidly decayed suggesting that local meteorology during the festive season was favorable for aerosol dispersion. A multiple linear regression (MLR) model with BC as the dependent variable and meteorological parameters as independent variables was fitted. The variability in temperature, humidity, wind speed, and wind direction accounted for about 49% of the variability in measured BC concentrations. Conditional probability function (CPF) analysis was used to identify the geographical location of local source regions contributing to the effective BC measured (at 880 nm) at the receptor site. The east north-east (ENE) direction to the receptor was identified as a major source region. National highway (NH8) and two coal-fired thermal power stations (at Gandhinagar and Sabarmati) were located in the identified direction, suggesting that local traffic and power plant emissions were likely contributors to the measured BC.

  9. Concentrations and bioaccessibility of metals in vegetation and dust near a mining haul road, Cape Krusenstern National Monument, Alaska

    USGS Publications Warehouse

    Brumbaugh, W.G.; Morman, S.A.; May, T.W.

    2011-01-01

    Vegetation, sub-surface peat, and road dust were sampled near the Delong Mountain Transportation System (DMTS) haul road in northwest Alaska in 2005-2006 to document aluminum, barium, cadmium, lead, and zinc concentrations, and to evaluate bioaccessibility of these metals. The DMTS haul road is the transport corridor between Red Dog Mine (a large-scale, lead-zinc mine and mill) and the coastal shipping port, and it traverses National Park Service lands. Compared to reference locations, total metal concentrations in four types of vegetation (birch, cranberry, and willow leaves, and cotton grass blades/stalks) collected 25 m from the haul road were enriched on average by factors of 3.5 for zinc, 8.0 for barium, 20 for cadmium, and 150 for lead. Triple rinsing of vegetation with a water/methanol mixture reduced metals concentrations by at most 50%, and cadmium and zinc concentrations were least affected by rinsing. Cadmium and zinc bioaccessibility was greater in vegetation (50% to 100%) than in dust (15% to 20%); whereas the opposite pattern was observed for lead bioaccessibility (<30% in vegetation; 50% in dust). Barium exhibited low-to-intermediate bioaccessibility in dust and vegetation (20% to 40%), whereas aluminum bioaccessibility was relatively low (<6%) in all sample types. Our reconnaissance-level study indicates that clean-up and improvements in lead/zinc concentrate transfer activities have been effective; however, as of 2006, metal dispersion from past and/or present releases of fugitive dusts along the DMTS road still may have been contributing to elevated metals in surface vegetation. Vegetation was most enriched in lead, but because bioaccessibility of cadmium was greater, any potential risks to animals that forage near the haul road might be equally important for both of these metals. ?? 2011 Springer Science+Business Media B.V. (outside the USA).

  10. Concentrations and bioaccessibility of metals in vegetation and dust near a mining haul road, Cape Krusenstern National Monument, Alaska

    USGS Publications Warehouse

    Brumbaugh, William G.; Morman, Suzette A.; May, Thomas W.

    2011-01-01

    Vegetation, sub-surface peat, and road dust were sampled near the Delong Mountain Transportation System (DMTS) haul road in northwest Alaska in 2005-2006 to document aluminum, barium, cadmium, lead, and zinc concentrations, and to evaluate bioaccessibility of these metals. The DMTS haul road is the transport corridor between Red Dog Mine (a large-scale, lead-zinc mine and mill) and the coastal shipping port, and it traverses National Park Service lands. Compared to reference locations, total metal concentrations in four types of vegetation (birch, cranberry, and willow leaves, and cotton grass blades/stalks) collected 25 m from the haul road were enriched on average by factors of 3.5 for zinc, 8.0 for barium, 20 for cadmium, and 150 for lead. Triple rinsing of vegetation with a water/methanol mixture reduced metals concentrations by at most 50%, and cadmium and zinc concentrations were least affected by rinsing. Cadmium and zinc bioaccessibility was greater in vegetation (50% to 100%) than in dust (15% to 20%); whereas the opposite pattern was observed for lead bioaccessibility (<30% in vegetation; 50% in dust). Barium exhibited low-to-intermediate bioaccessibility in dust and vegetation (20% to 40%), whereas aluminum bioaccessibility was relatively low (<6%) in all sample types. Our reconnaissance-level study indicates that clean-up and improvements in lead/zinc concentrate transfer activities have been effective; however, as of 2006, metal dispersion from past and/or present releases of fugitive dusts along the DMTS road still may have been contributing to elevated metals in surface vegetation. Vegetation was most enriched in lead, but because bioaccessibility of cadmium was greater, any potential risks to animals that forage near the haul road might be equally important for both of these metals.

  11. Mining in subarctic Canada: airborne PM2.5 metal concentrations in two remote First Nations communities.

    PubMed

    Liberda, Eric N; Tsuji, Leonard J S; Peltier, Richard E

    2015-11-01

    Airborne particulate matter arising from upwind mining activities is a concern for First Nations communities in the western James Bay region of Ontario, Canada. Aerosol chemical components were collected in 2011 from two communities in northern Ontario. The chemical and mass concentration data of particulate matter collected during this study shows a significant difference in PM2.5 in Attawapiskat compared to Fort Albany. Elemental profiles indicate enhanced levels of some tracers thought to arise from mining activities, such as, K, Ni, and crustal materials. Both communities are remote and isolated from urban and industrial pollution sources, however, Attawapiskat First Nation has significantly enhanced levels of particulate matter, and it is likely that some of this arises from upwind mining activities.

  12. Alternative statistical methods for interpreting airborne Alder ( Alnus glutimosa (L.) Gaertner) pollen concentrations

    NASA Astrophysics Data System (ADS)

    González Parrado, Zulima; Valencia Barrera, Rosa M.; Fuertes Rodríguez, Carmen R.; Vega Maray, Ana M.; Pérez Romero, Rafael; Fraile, Roberto; Fernández González, Delia

    2009-01-01

    This paper reports on the behaviour of Alnus glutinosa (alder) pollen grains in the atmosphere of Ponferrada (León, NW Spain) from 1995 to 2006. The study, which sought to determine the effects of various weather-related parameters on Alnus pollen counts, was performed using a volumetric method. The main pollination period for this taxon is January-February. Alder pollen is one of the eight major airborne pollen allergens found in the study area. An analysis was made of the correlation between pollen counts and major weather-related parameters over each period. In general, the strongest positive correlation was with temperature, particularly maximum temperature. During each period, peak pollen counts occurred when the maximum temperature fell within the range 9°C-14°C. Finally, multivariate analysis showed that the parameter exerting the greatest influence was temperature, a finding confirmed by Spearman correlation tests. Principal components analysis suggested that periods with high pollen counts were characterised by high maximum temperature, low rainfall and an absolute humidity of around 6 g m-3. Use of this type of analysis in conjunction with other methods is essential for obtaining an accurate record of pollen-count variations over a given period.

  13. Concentrations of polycyclic aromatic hydrocarbons in resuspendable fraction of settled bus dust and its implications for human exposure.

    PubMed

    Gao, Peng; Liu, Sa; Feng, Yujie; Lin, Nan; Lu, Binyu; Zhang, Zhaohan; Cui, Fuyi; Xing, Baoshan; Hammond, S Katharine

    2015-03-01

    This preliminary study measured Polycyclic Aromatic Hydrocarbons (PAHs) concentrations in the resuspendable fraction of settled dust on 39 bus lines, to evaluate the impact of engine type (gasoline and compressed natural gas) on exposure for commuters and drivers. Benzo(b)fluoranthene(BbF) was the predominant PAH in resuspendable fraction of settled bus dust. The concentration of total PAHs was 92.90 ± 116.00 μg/g (range: 0.57-410) in gasoline buses and 3.97 ± 1.81 (range: 2.01-9.47) in compressed natural gas (CNG) buses. Based on Benzo[a]pyrene (BaP) equivalent concentrations for the sum of 16 PAHs, the average daily dose (ADD) via dust ingestion and dermal contact was calculated. The ADD of PAHs was higher for commuters and drivers in gasoline-powered buses than in buses using CNG buses. For both short and long duration journeys, young commuters were exposed to higher levels of PAHs via dust ingestion and dermal contact than adult commuters.

  14. Concentrations of "legacy" and novel brominated flame retardants in matched samples of UK kitchen and living room/bedroom dust.

    PubMed

    Kuang, Jiangmeng; Ma, Yuning; Harrad, Stuart

    2016-04-01

    Concentrations of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs) and 5 novel brominated flame retardants (NBFRs) were measured in paired samples of kitchen and living room/bedroom dust sampled in 2015 from 30 UK homes. BDE-209 was most abundant (22-170,000 ng/g), followed by γ-HBCDD (1.7-21,000 ng/g), α-HBCDD (5.2-4,900 ng/g), β-HBCDD (2.3-1,600 ng/g), BDE-99 (2.6-1,440 ng/g), BDE-47 (0.4-940 ng/g), decabromodiphenyl ethane (DBDPE) (nd-680 ng/g) and bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP) (2.7-630 ng/g). The concentrations in kitchens and living rooms/bedrooms are moderate compared with previous studies. Concentrations of BDE-209 in living room/bedroom dust were significantly lower and those of DBDPE significantly higher (p < 0.05) compared to concentrations recorded in UK house dust in 2006 and 2007. This may reflect changes in UK usage of these BFRs. All target BFRs were present at higher concentrations in living rooms/bedrooms than kitchens. With the exception of BDE-28, pentabromoethylbenzene (PBEB) and DBDPE, these differences were significant (p < 0.05). No specific source was found that could account for the higher concentrations in living rooms/bedrooms.

  15. Cloud ice caused by atmospheric mineral dust - Part 1: Parameterization of ice nuclei concentration in the NMME-DREAM model

    NASA Astrophysics Data System (ADS)

    Nickovic, Slobodan; Cvetkovic, Bojan; Madonna, Fabio; Rosoldi, Marco; Pejanovic, Goran; Petkovic, Slavko; Nikolic, Jugoslav

    2016-09-01

    Dust aerosols are very efficient ice nuclei, important for heterogeneous cloud glaciation even in regions distant from desert sources. A new generation of ice nucleation parameterizations, including dust as an ice nucleation agent, opens the way towards a more accurate treatment of cold cloud formation in atmospheric models. Using such parameterizations, we have developed a regional dust-atmospheric modelling system capable of predicting, in real time, dust-induced ice nucleation. We executed the model with the added ice nucleation component over the Mediterranean region, exposed to moderate Saharan dust transport, over two periods lasting 15 and 9 days, respectively. The model results were compared against satellite and ground-based cloud-ice-related measurements, provided by SEVIRI (Spinning Enhanced Visible and InfraRed Imager) and the CNR-IMAA Atmospheric Observatory (CIAO) in Potenza, southern Italy. The predicted ice nuclei concentration showed a reasonable level of agreement when compared against the observed spatial and temporal patterns of cloud ice water. The developed methodology permits the use of ice nuclei as input into the cloud microphysics schemes of atmospheric models, assuming that this approach could improve the predictions of cloud formation and associated precipitation.

  16. Personal indium exposure concentration in respirable dusts and serum indium level

    PubMed Central

    IWASAWA, Satoko; NAKANO, Makiko; MIYAUCHI, Hiroyuki; TANAKA, Shigeru; KAWASUMI, Yaeko; HIGASHIKUBO, Ichiro; TANAKA, Akiyo; HIRATA, Miyuki; OMAE, Kazuyuki

    2016-01-01

    The aim of this study was to assess the relationship between indium exposure concentration in the respirable dust fraction (In-E) and indium in serum (In-S) in workers. Methods: A total of 39 workers were studied. The study subjects were categorized into 3 groups, namely, smelting workers (n=7), ITO workers (n=6) in an ITO grinding plant, and other workers (n=26). In-E and In-S ranged from 0.004–24.0 μg/m3 and 0.1–8.50 μg/L, respectively. The simple regression equation was log(In-S)=0.322×log(In-E)−0.443. The simple correlation coefficients for the smelting workers, ITO workers and other workers were 0.489, 0.812 and 0.163, respectively. The differences in the relationships among the three groups suggest that In-S may vary with the chemical form to which the workers were exposed. In-E and In-S seem to be positively correlated. The correlation coefficient was higher for both smelting and ITO workers than for other workers. PMID:27644848

  17. Use of a directional spray system design to control respirable dust and face gas concentrations around a continuous mining machine.

    PubMed

    Goodman, Gerrit V R; Pollock, Douglas E

    2004-12-01

    A laboratory study assessed the impacts of water spray pressure, face ventilation quantity, and line brattice setback distance on respirable dust and SF6 tracer gas concentrations around a continuous mining machine using a sprayfan or directional spray system. Dust levels were measured at locations representing the mining machine operator and the standard and off-standard shuttle car operators, and in the return airway. The results showed that changes in all three independent variables significantly affected log-transformed dust levels at the three operator sampling locations. Changes in setback distance impacted return airway dust levels. Laboratory testing also identified numerous variable interactions affecting dust levels. Tracer gas levels were measured on the left and right sides of the cutting drum and in the return. Untransformed gas levels around the cutting drum were significantly affected by changes in water pressure, face ventilation quantity, and setback distance. Only a few interactions were identified that significantly affected these concentrations. Gas levels in the return airway were grouped by face ventilation quantity. Return gas levels measured at the low curtain quantity were generally unaffected by changes in water pressure or curtain setback distance. At the high curtain quantity, return airway gas levels were affected by curtain setback distance. A field study was conducted to assess the impact of these parameters in an actual mining operation. These data showed that respirable dust levels may have been impacted by a change in water pressure and, to a lesser extent, by an increase in curtain setback distance. A series of tracer gas pulse tests were also conducted during this study. The results showed that effectiveness of the face ventilation was impacted by changes in curtain flow quantity and setback distance. Laboratory testing supported similar conclusions.

  18. The role of dust storms in total atmospheric particle concentrations at two sites in the western U.S.

    USGS Publications Warehouse

    Neff, Jason C.; Reynolds, Richard L.; Munson, Seth M.; Fernandez, Daniel; Belnap, Jayne

    2013-01-01

    Mineral aerosols are produced during the erosion of soils by wind and are a common source of particles (dust) in arid and semiarid regions. The size of these particles varies widely from less than 2 µm to larger particles that can exceed 50 µm in diameter. In this study, we present two continuous records of total suspended particle (TSP) concentrations at sites in Mesa Verde and Canyonlands National Parks in Colorado and Utah, USA, respectively, and compare those values to measurements of fine and coarse particle concentrations made from nearby samplers. Average annual concentrations of TSP at Mesa Verde were 90 µg m−3 in 2011 and at Canyonlands were 171 µg m−3 in 2009, 113 µg m−3 in 2010, and 134 µg m−3 in 2011. In comparison, annual concentrations of fine (diameter of 2.5 µm and below) and coarse (2.5–10 µm diameter) particles at these sites were below 10 µg m−3 in all years. The high concentrations of TSP appear to be the result of regional dust storms with elevated concentrations of particles greater than 10 µm in diameter. These conditions regularly occur from spring through fall with 2 week mean TSP periodically in excess of 200 µg m−3. Measurement of particles on filters indicates that the median particle size varies between approximately 10 µm in winter and 40 µm during the spring. These persistently elevated concentrations of large particles indicate that regional dust emission as dust storms and events are important determinants of air quality in this region.

  19. Historical ambient airborne asbestos concentrations in the United States - an analysis of published and unpublished literature (1960s-2000s).

    PubMed

    Abelmann, Anders; Glynn, Meghan E; Pierce, Jennifer S; Scott, Paul K; Serrano, Samantha; Paustenbach, Dennis J

    2015-01-01

    Outdoor concentrations of airborne asbestos have been measured throughout the US over time. However, a thorough review and analysis of these data has not been conducted. The purpose of this study is to characterize asbestos concentrations in ambient air by environment type (urban, rural) and by decade, using measurements collected in the absence of known asbestos emission sources. A total of 17 published and unpublished studies and datasets were identified that reported the results of 2058 samples collected from the 1960s through the 2000s across the US. Most studies did not report asbestos fiber type, and data based on different analytical methods (e.g. Phase Contrast Microscopy, Transmission Electron Microscopy, etc.) were combined in the dataset; however, only fibers ≥5 μm in length were considered. For a small subset of the measurements (n = 186, 9.0%), a conversion factor was used to convert mass-based data (e.g. ng/m(3)) to count-based values (i.e. f/cc ≥5 μm). The estimated overall mean and median ambient asbestos concentrations for the 1960s through 2000s were 0.00093 f/cc and 0.00022 f/cc, respectively. Concentrations generally increased from the 1960s through the early 1980s, after which they declined considerably. While asbestos use decreased throughout the 1970s, these results indicate that ambient concentrations peaked during the early 1980s, which suggests the possible contribution of abatement or demolition activities. Lastly, ambient asbestos concentrations were higher in urban than rural settings, which is consistent with the greater use of asbestos-containing materials in more densely populated areas.

  20. Defining an Abrasion Index for Lunar Surface Systems as a Function of Dust Interaction Modes and Variable Concentration Zones

    NASA Technical Reports Server (NTRS)

    Kobrick, Ryan L.; Klaus, David M.; Street, Kenneth W., Jr.

    2010-01-01

    Unexpected issues were encountered during the Apollo era of lunar exploration due to detrimental abrasion of materials upon exposure to the fine-grained, irregular shaped dust on the surface of the Moon. For critical design features involving contact with the lunar surface and for astronaut safety concerns, operational concepts and dust tolerance must be considered in the early phases of mission planning. To systematically define material selection criteria, dust interaction can be characterized by two-body or three-body abrasion testing, and subcategorically by physical interactions of compression, rolling, sliding and bending representing specific applications within the system. Two-body abrasion occurs when a single particle or asperity slides across a given surface removing or displacing material. Three-body abrasion occurs when multiple particles interact with a solid surface, or in between two surfaces, allowing the abrasives to freely rotate and interact with the material(s), leading to removal or displacement of mass. Different modes of interaction are described in this paper along with corresponding types of tests that can be utilized to evaluate each configuration. In addition to differential modes of abrasion, variable concentrations of dust in different zones can also be considered for a given system design and operational protocol. These zones include: (1) outside the habitat where extensive dust exposure occurs, (2) in a transitional zone such as an airlock or suitport, and (3) inside the habitat or spacesuit with a low particle count. These zones can be used to help define dust interaction frequencies, and corresponding risks to the systems and/or crew can be addressed by appropriate mitigation strategies. An abrasion index is introduced that includes the level of risk, R, the hardness of the mineralogy, H, the severity of the abrasion mode, S, and the frequency of particle interactions, F.

  1. Statistical distributions of airborne PCB and pesticide concentrations measured at regional sites on the Great Lakes

    SciTech Connect

    Gatz, D.F.; Sweet, C.W.; Basu, I.; Harlin, K.S.

    1994-12-31

    The purpose of this paper is to report results of testing measured concentrations of total PCBs and ten chlorinated pesticides in air and precipitation in the Great Lakes area for goodness-of-fit to the log normal distribution. Samples were collected at sites on Lakes Superior, Michigan, Erie, and Ontario in 1991--1993. With very few exceptions, distributions of concentrations in the gas and particle phases and in precipitation were not significantly different from log normal.

  2. National and regional distributions of airborne radon concentrations in US homes

    SciTech Connect

    Marcinowski, F.; Lucas, R.M.; Yeager, W.M.

    1994-06-01

    The National Residential Radon Survey was conducted during 1989 and 1990 to provide data on the frequency distribution of annual average radon concentrations in U.S. residences nationwide, in U.S. Environmental Protection Agency defined Regions, and in subgroups of the housing stock. The National Residential Radon Survey also provided housing and demographic data and a preliminary assessment of the relationship of housing and geographical characteristics to residential radon concentrations. This paper focuses solely on the national and regional estimates of annual average radon concentrations. A stratified, three-stage sampling procedure was used to select housing units for the survey. Data were collected through personal interviews with residents and placement of alpha track detectors in each level of the residences for 12 mo. The survey found an arithmetic annual average radon concentration in U.S. homes of 46.3 {plus_minus} 4.4 Bq m{sup {minus}3} (1.25 {plus_minus} 0.12 pCi L{sup {minus}}). About 6.0 {plus_minus} 1.4% of homes (5.8 million) had radon levels greater than the U.S. Environmental Protection Agency`s action level for mitigation of 148 Bq m{sup {minus}3} (4 pCi L{sup {minus}1}). Concentrations varied significantly across Environmental Protection Agency Regions. A lognormal distribution was found to closely approximate the major distributions of radon concentrations. 9 refs., 2 figs., 8 tabs.

  3. Spatial variations in airborne microorganism and endotoxin concentrations at green waste composting facilities.

    PubMed

    Pankhurst, L J; Deacon, L J; Liu, J; Drew, G H; Hayes, E T; Jackson, S; Longhurst, P J; Longhurst, J W S; Pollard, S J T; Tyrrel, S F

    2011-09-01

    The emission and dispersal of bioaerosols from open-air commercial composting facilities continues to be contentious. A meta-dataset enumerating cultivable microorganism emission and downwind concentrations is not yet available. A dataset derived from repeated and replicated field studies over a period of two years at two commercial composting facilities is presented. The data characterises patterns in Aspergillus fumigatus, actinomycetes, Gram-negative bacteria and endotoxin emission and downwind concentrations. For all bioaerosols, compost agitation activities had a significant impact on concentrations; levels were variable up to 600 m downwind from site. Bioaerosols declined rapidly from source and exhibited a secondary peak 100-150 m from site boundary. All bioaerosols were found downwind from site in elevated concentrations. Compared to those found 100 m upwind, levels were significantly higher at 180 m downwind for A. fumigatus; at 300-400 m for actinomycetes and Gram negative bacteria, and at 100 m for endotoxins. Periodically, elevated concentrations could be found for all bioaerosols at distances further downwind. The evidence provided by this data set provides operators and regulators of facilities with reliable data to inform the location, risk assessment and bioaerosol sampling strategies of commercial composting facilities.

  4. Is It Possible to Distinguish Between Dust and Salt Aerosol Over Waters with Unknown Chlorophyll Concentrations Using Spectral Remote Sensing?

    NASA Technical Reports Server (NTRS)

    Levy, R. C.; Kaufman, Y. J.

    1999-01-01

    Atmospheric aerosol has uncertain impacts on the global climate system, as well as on atmospheric and bio-geo-chemical processes of regional and local scales. EOS-MODIS is one example of a satellite sensor designed to improve understanding of the aerosols' type, size and distribution at all temporal and spatial scales. Ocean scientists also plan to use data from EOS-MODIS to assess the temporal and spatial coverage of in-water chlorophyll. MODIS is the first sensor planned to observe the combined ocean-atmosphere system with a wide spectral range (from 410 to 2200 nm). Dust aerosol and salt aerosol have similar spectral signals for wavelengths longer than 550 nm, but because dust selectively absorbs blue light, they have divergent signals in the blue wavelength regions (412 to 490 nm). Chlorophyll also selectively absorbs blue radiation, so that varying chlorophyll concentrations produces a highly varying signal in the blue regions, but less variability in the green, and almost no signal in the red to mid-infrared regions. Thus, theoretically, it may be difficult to differentiate dust and salt in the presence of unknown chlorophyll in the ocean. This study attempts to address the cases in which aerosol and chlorophyll signals can and cannot be separated. For the aerosol spectra, we use the aerosol lookup table from the operational MODIS aerosol-over-ocean algorithm, and for chlorophyll spectra, we use the SeaBAM data set (created for SeaWiFS). We compare the signals using Principal Component Analysis and attempt to retrieve both chlorophyll and aerosol properties using a variant of the operational MODIS aerosol-over-ocean algorithm. Results show that for small optical depths, less than 0.5, it is not possible to differentiate between dust and salt and to determine the chlorophyll concentration at the same time. For larger aerosol optical depths, the chlorophyll signals are comparatively insignificant, and we can hope to distinguish between dust and salt.

  5. 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

  6. Instituting a filtration/pressurization system to reduce dust concentrations in a control room at a mineral processing plant.

    PubMed

    Noll, J; Cecala, A; Hummer, J

    2015-12-01

    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.

  7. Vertical distribution of aerosol number concentration in the troposphere over Siberia derived from airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail Yu.; Belan, Boris D.; Paris, Jean-Daniel; Machida, Toshinobu; Kozlov, Alexandr; Malyskin, Sergei; Simonenkov, Denis; Davydov, Denis; Fofonov, Alexandr

    2016-04-01

    Knowledge of the vertical distribution of aerosols particles is very important when estimating aerosol radiative effects. To date there are a lot of research programs aimed to study aerosol vertical distribution, but only a few ones exist in such insufficiently explored region as Siberia. Monthly research flights and several extensive airborne campaigns carried out in recent years in Siberian troposphere allowed the vertical distribution of aerosol number concentration to be summarized. In-situ aerosol measurements were performed in a wide range of particle sizes by means of improved version of the Novosibirsk-type diffusional particle sizer and GRIMM aerosol spectrometer Model 1.109. The data on aerosol vertical distribution enabled input parameters for the empirical equation of Jaenicke (1993) to be derived for Siberian troposphere up to 7 km. Vertical distributions of aerosol number concentration in different size ranges averaged for the main seasons of the year will be presented. This work was supported by Interdisciplinary integration projects of the Siberian Branch of the Russian Academy of Science No. 35, No. 70 and No. 131; the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); and Russian Foundation for Basic Research (grant No. 14-05-00526). Jaenicke R. Tropospheric aerosols, in Aerosol-Cloud-Climate Interactions, edited by P.V. Hobs. -Academic Press, San Diego, CA, 1993.- P. 1-31.

  8. Large-scale radon hazard evaluation in the Oslofjord region of Norway utilizing indoor radon concentrations, airborne gamma ray spectrometry and geological mapping.

    PubMed

    Smethurst, Mark Andrew; Strand, Terje; Sundal, Aud Venke; Rudjord, Anne Liv

    2008-12-15

    We test whether airborne gamma ray spectrometer measurements can be used to estimate levels of radon hazard in the Oslofjord region of Norway. We compile 43,000 line kilometres of gamma ray spectrometer data from 8 airborne surveys covering 10,000 km2 and compare them with 6326 indoor radon measurements. We find a clear spatial correlation between areas with elevated concentrations of uranium daughters in the near surface of the ground and regions with high incidence of elevated radon concentrations in dwellings. This correlation permits cautious use of the airborne data in radon hazard evaluation where direct measurements of indoor radon concentrations are few or absent. In radon hazard evaluation there is a natural synergy between the mapping of radon in indoor air, bedrock and drift geology mapping and airborne gamma ray surveying. We produce radon hazard forecast maps for the Oslofjord region based on a spatial union of hazard indicators from all four of these data sources. Indication of elevated radon hazard in any one of the data sets leads to the classification of a region as having an elevated radon hazard potential. This approach is inclusive in nature and we find that the majority of actual radon hazards lie in the assumed elevated risk regions.

  9. Measurement of Polycyclic Aromatic Hydrocarbons in Airborne Particulate Matter at Low Concentrations

    DTIC Science & Technology

    2012-03-01

    Soil & Water Colorimetric (diphenylcarbazide) 7199 Hexavalent Chromium by Ion Chromatography 218.6 Low level chelation & extraction NATTS...Hexane:Dichloromethane:Methanol Dionex ASE 200 Sample Concentration Evaporation in Ultrapure Nitrogen Stream Zymark Turbovap Solid Phase Extraction Supelco Custom...Glass Silica SPE Cartridge 1% Dichloromethane + 1% Acetone in Hexane GCMS Analysis Conventional Splitless Injection Selective Ion Monitoring

  10. Integrity of Lichen Cell Membranes in Relation to Concentration of Airborne Elements

    PubMed

    Garty; Kloog; Cohen

    1998-02-01

    This study dealt with the impact of air pollution on the integrity of cell membranes in the lichen Ramalina duriaei. The lichen was transplanted from a relatively unpolluted site in Israel to more polluted sites, adjacent to a 40-year-old town, for a period of 10 months. The concentrations of K, B, Al, Cr, Fe, Si, Ti, Zn, P, Ba, Cu, Mg, Na, Pb, Ca, Mn, Sr, and S in lichen thalli were compared with injury caused to the cell membranes. The study indicates that electric conductivity reflects adequately cellular injury to lichen thalli transplanted to sites near a motorway, an oil-fueled power plant and a rural community (a kibbutz). The concentrations of S, B, Al, Cr, Fe, Si, Ti, and Zn correlated with injury in cell membranes of R. duriaei retrieved from the biomonitoring sites, whereas the concentration of K in the thalli correlated inversely with the electric conductivity parameter. Leakage of K from lichen thalli as a result of air pollutants is suggested. This K leakage correlates positively with concentrations of S and Cr in transplants of R. duriaei to the Ashdod region.

  11. An improved filter pack technique for airborne measurement of low concentrations of SO2

    NASA Astrophysics Data System (ADS)

    Ferek, Ronald J.; Hegg, Dean A.; Herring, John A.; Hobbs, Peter V.

    1991-12-01

    Recent improvements to the carbonate-impregnated filter technique for measuring low-level SO2concentrations have resulted in dramatically improved performance. The improvements are (1) a better cleaning procedure for the paper filter substrates, resulting in approximately 60% reduction of their sulfate blank, (2) the use of an ion-exchange resin to remove the carbonate matrix from the sample extract, resulting in a 100% increase in the signal-to-noise ratio, (3) the use of high-purity glycerol in the filter impregnate, resulting in approximately 10% further reduction of blanks, and (4) improved Chromatographic and standardization procedures for more accurate quantification of sample peaks. Combined, these improvements allow measurements to be made of SO2 concentrations in marine background air with a 2σ uncertainty of ±6 parts per trillion by volume (pptv) and, based on this, a 3σ detection limit of 9 pptv for air volumes of 4 m3 (which can be collected in 15 min aboard our research aircraft). Measurements in polluted air show better than 95% collection efficiency, even at concentrations as high as 100 ppbv. Vertical profiles of SO2 measured during three research flights off the Washington coast (one in clean marine air) showed concentrations ranging from 15 to 86 pptv in the mixed layer and from 40 to 93 pptv in the free troposphere.

  12. Trends and threshold exceedances analysis of airborne pollen concentrations in Metropolitan Santiago Chile

    PubMed Central

    Toro A., Richard; Córdova J., Alicia; Canales, Mauricio; Morales S., Raul G. E.; Mardones P., Pedro; Leiva G., Manuel A.

    2015-01-01

    Pollen is one of the primary causes of allergic rhinoconjunctivitis in urban centers. In the present study, the concentrations of 39 different pollens in the Santiago de Chile metropolitan area over the period 2009–2013 are characterized. The pollen was monitored daily using Burkard volumetric equipment. The contribution of each type of pollen and the corresponding time trends are evaluated. The concentrations of the pollens are compared with the established threshold levels for the protection of human health. The results show that the total amount of pollen grains originating from trees, grasses, weeds and indeterminate sources throughout the period of the study was 258,496 grains m-3, with an annual average of 51,699 ± 3,906 grains m-3 year-1. The primary source of pollen is Platanus orientalis, which produces 61.8% of the analyzed pollen. Grass pollen is the third primary component of the analyzed pollen, with a contribution of 5.82%. Among the weeds, the presence of Urticacea (3.74%) is remarkable. The pollination pattern of the trees is monophasic, and the grasses have a biphasic pattern. The trends indicate that the total pollen and tree pollen do not present a time trend that is statistically significant throughout the period of the study, whereas the grass pollen and weed pollen concentrations in the environment present a statistically significant decreasing trend. The cause of this decrease is unclear. The pollen load has doubled over the past decade. When the observed concentrations of the pollens were compared with the corresponding threshold levels, the results indicated that over the period of the study, the pollen concentrations were at moderate, high and very high levels for an average of 293 days per year. Systematic counts of the pollen grains are an essential method for diagnosing and treating patients with pollinosis and for developing forestation and urban planning strategies. PMID:25946339

  13. Trends and threshold exceedances analysis of airborne pollen concentrations in Metropolitan Santiago Chile.

    PubMed

    Toro A, Richard; Córdova J, Alicia; Canales, Mauricio; Morales S, Raul G E; Mardones P, Pedro; Leiva G, Manuel A

    2015-01-01

    Pollen is one of the primary causes of allergic rhinoconjunctivitis in urban centers. In the present study, the concentrations of 39 different pollens in the Santiago de Chile metropolitan area over the period 2009-2013 are characterized. The pollen was monitored daily using Burkard volumetric equipment. The contribution of each type of pollen and the corresponding time trends are evaluated. The concentrations of the pollens are compared with the established threshold levels for the protection of human health. The results show that the total amount of pollen grains originating from trees, grasses, weeds and indeterminate sources throughout the period of the study was 258,496 grains m-3, with an annual average of 51,699 ± 3,906 grains m-3 year-1. The primary source of pollen is Platanus orientalis, which produces 61.8% of the analyzed pollen. Grass pollen is the third primary component of the analyzed pollen, with a contribution of 5.82%. Among the weeds, the presence of Urticacea (3.74%) is remarkable. The pollination pattern of the trees is monophasic, and the grasses have a biphasic pattern. The trends indicate that the total pollen and tree pollen do not present a time trend that is statistically significant throughout the period of the study, whereas the grass pollen and weed pollen concentrations in the environment present a statistically significant decreasing trend. The cause of this decrease is unclear. The pollen load has doubled over the past decade. When the observed concentrations of the pollens were compared with the corresponding threshold levels, the results indicated that over the period of the study, the pollen concentrations were at moderate, high and very high levels for an average of 293 days per year. Systematic counts of the pollen grains are an essential method for diagnosing and treating patients with pollinosis and for developing forestation and urban planning strategies.

  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. PM10 Concentration levels at an urban and background site in Cyprus: The impact of urban sources and dust storms

    PubMed Central

    Achilleos, Souzana; Evans, John S.; Yiallouros, Panayiotis K.; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

    2016-01-01

    Air quality in Cyprus is influenced by both local and transported pollution including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993 through December 11, 2008, and Ayia Marina (rural background representative) from January 1, 1999 through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records and satellite data were used to identify dust storm days. We investigated long term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year. A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000–2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact of dust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. PMID:25562931

  16. Magnetic characterization of airborne particulates

    NASA Astrophysics Data System (ADS)

    Kim, W.; Doh, S.; Yu, Y.

    2010-12-01

    Burning fossil fuels from vehicles, domestics, industries and power plants in the large urban or industrial areas emit significant quantity of anthropogenic particulates which become a potential threat to human health. Here, we present temporal variability of particulate pollution associated with compositional differences, using magnetic measurements and electron microscopic observations. Six different grain-sizes of airborne particulates have been collected by filtering from 10 precipitation events in Seoul, Korea from February 2009 to June 2009. Magnetic concentration proxies show relatively better (R2 >0.6) and poorer correlations (R2 <0.3) with the masses of samples filtered by >0.45 μm and <0.45 μm sizes, respectively, suggesting the usefulness of magnetic characterization for the >0.45 μm particulates. Temporally, magnetic concentrations are higher in the cold season than the warm season. In particular, a significant increase of magnetic concentration is observed in 3 μm and 1 μm filters after the Chinese wind-blown dust events, indicating additional influx of fine-grained anthropogenic particulates into Seoul. Microscopic observations identify that increase of magnetic concentration is highly linked with the frequent occurrence of combustion derived particulates (i.e., carbon and/or sulfur mixed particles) than natural alumino-silicates. Overall, the present study demonstrates that magnetic measurements efficiently reflect the concentration of particulates produced from fossil-fuel combustion among the airborne particles from various sources.

  17. Modeling airborne benzo(a)pyrene concentrations in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Zalel, Amir; Yuval; Svecova, Vlasta; Sram, Radim J.; Bartonova, Alena; Broday, David M.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are complex hazardous organic compounds that are introduced into the atmosphere as by-products of partial combustion processes. For common atmospheric conditions, the large molecular weight PAHs, such as benzo(a)pyrene (B[a]P), are found in the particulate phase and are believed to account for a considerable amount of the fine particulate matter toxic potential. Nonetheless, unlike meteorological variables and criteria pollutants, PAHs are very rarely monitored on a routine basis in most parts of the world. We present methodology for development and evaluation of a model for estimation of daily and monthly ambient B[a]P concentrations. The model utilizes a very large ambient B[a]P database from three sites in the Czech Republic. The difficulties faced when dealing with ambient PAH data are discussed. Model performance was evaluated by a complete internal-, external-, and temporal cross validations. The models reproduced very accurately monthly mean ambient B[a]P concentrations and provided acceptable daily mean B[a]P concentrations. Spatial extrapolations resulted in small deterioration of the models' performance. The temporal backward extrapolation revealed comparable errors to the spatial extrapolations in spite of the dramatic emissions reduction in the early years of the study period.

  18. Climate impact on airborne particulate matter concentrations in California using seven year analysis periods

    NASA Astrophysics Data System (ADS)

    Mahmud, A.; Hixson, M.; Hu, J.; Zhao, Z.; Chen, S.; Kleeman, M. J.

    2010-02-01

    The effect of global climate change on the annual average concentration of fine particulate matter (PM2.5) in California was studied using a climate - air quality modeling system composed of global through regional models. Output from the NCAR/DOE Parallel Climate Model (PCM) generated under the "business as usual" global emissions scenario was downscaled using the Weather Research and Forecasting (WRF) model followed by air quality simulations using the UCD/CIT airshed model. The air quality simulations were carried out for the entire state of California with a resolution of 8-km for the years 2000-2006 (present climate) and 2047-2053 (future climate). The 7-year windows were chosen to properly account for annual variability with the added benefit that the air quality predictions under the present climate could be compared to actual measurements. The climate - air quality modeling system successfully predicted the spatial pattern of present climate PM2.5 concentrations in California but the absolute magnitude of the annual average PM2.5 concentrations were under-predicted by ~35-40% in the major air basins. The majority of this under-prediction was caused by excess ventilation predicted by PCM-WRF that should be present to the same degree in the current and future time periods so that the net bias introduced into the comparison is minimized. Surface temperature, relative humidity (RH), rain rate, and wind speed were predicted to increase in the future climate while the ultra violet (UV) radiation was predicted to decrease in major urban areas in the San Joaquin Valley (SJV) and South Coast Air Basin (SoCAB). These changes resulted in a ~0.6-1.9 μg m-3 decrease in predicted PM2.5 concentrations in coastal and central Los Angeles. Annual average PM2.5 concentrations were predicted to increase at certain locations within the SJV and the Sacramento Valley due to the effects of climate change, but a corresponding analysis of the annual variability showed that these

  19. The effect of meteorological factors on airborne Betula pollen concentrations in Lublin (Poland).

    PubMed

    Piotrowska, Krystyna; Kubik-Komar, Agnieszka

    2012-12-01

    The present study investigated the pattern of the birch atmospheric pollen seasons in Lublin in the period 2001-2010. Pollen monitoring was conducted using a Lanzoni VPPS 2000 sampler. The atmospheric pollen seasons were determined with the 98% method. Regression analysis was used to determine correlations between meteorological conditions and the pattern of the birch pollen season. On average, the birch pollen season started on 12 April, ended on 13 May, and lasted 32 days. The peak value and the Seasonal Pollen Index showed the greatest variation in particular years. All the seasons were right-skewed. During the study years, a trend was found towards earlier occurrence of the seasonal peak. Regression equations were developed for the following parameters of the atmospheric pollen season: start, duration, peak value and average pollen concentration during the season. The obtained model fit was at a level of 64-81%. Statistical analysis shows that minimum temperature of February and March and total rainfall in June in the year preceding pollen release have the greatest effect on the birch atmospheric pollen season in Lublin. Low temperatures in February promote the occurrence of high pollen concentrations.

  20. Transport of Alaskan Dust into the Gulf of Alaska and Comparison with Similar High-Latitude Dust Environments

    NASA Technical Reports Server (NTRS)

    Crusium, John; Levy, Rob; Wang, Jun; Campbell, Rob; Schroth, Andrew W.

    2012-01-01

    Transport of Alaskan dust into the Gulf of Alaska and comparison with similar high-latitude dust environments. An airborne flux of the micronutrient iron, derived from dust originating from coastal regions may be an important contributor of iron to the Gulf of Alaska's (GoA) oligotrophic waters. Dust blowing off glacier termini and dry riverbeds is a recurring phenomenon in Alaska, usually occurring in the autumn. Since previous studies assumed that dust originating in the deserts of Asia was the largest source of . airborne iron to the GoA, the budget of aeolian deposition of iron needs to be reassessed. Since late 20 I 0, our group has been monitoring dust activity using satellites over the Copper River Delta (CRD) where the most vigorous dust plumes have been observed. Since 2011, sample aerosol concentration and their composition are being collected at Middleton Island (100km off shore of CRD). This presentation will show a summary of the ongoing dust observations and compare with other similar environments (Patagonia, Iceland) by showing case studies. Common features will be highlighted

  1. 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.

  2. Climate impact on airborne particulate matter concentrations in California using seven year analysis periods

    NASA Astrophysics Data System (ADS)

    Mahmud, A.; Hixson, M.; Hu, J.; Zhao, Z.; Chen, S.-H.; Kleeman, M. J.

    2010-11-01

    The effect of global climate change on the annual average concentration of fine particulate matter (PM2.5) in California was studied using a climate-air quality modeling system composed of global through regional models. Output from the NCAR/DOE Parallel Climate Model (PCM) generated under the "business as usual" global emissions scenario was downscaled using the Weather Research and Forecasting (WRF) model followed by air quality simulations using the UCD/CIT airshed model. The system represents major atmospheric processes acting on gas and particle phase species including meteorological effects on emissions, advection, dispersion, chemical reaction rates, gas-particle conversion, and dry/wet deposition. The air quality simulations were carried out for the entire state of California with a resolution of 8-km for the years 2000-2006 (present climate with present emissions) and 2047-2053 (future climate with present emissions). Each of these 7-year analysis periods was analyzed using a total of 1008 simulated days to span a climatologically relevant time period with a practical computational burden. The 7-year windows were chosen to properly account for annual variability with the added benefit that the air quality predictions under the present climate could be compared to actual measurements. The climate-air quality modeling system successfully predicted the spatial pattern of present climate PM2.5 concentrations in California but the absolute magnitude of the annual average PM2.5 concentrations were under-predicted by ~4-39% in the major air basins. The majority of this under-prediction was caused by excess ventilation predicted by PCM-WRF that should be present to the same degree in the current and future time periods so that the net bias introduced into the comparison is minimized. Surface temperature, relative humidity (RH), rain rate, and wind speed were predicted to increase in the future climate while the ultra violet (UV) radiation was predicted to decrease

  3. Use of dust fall filters as passive samplers for metal concentrations in air for communities near contaminated mine tailings.

    PubMed

    Beamer, P I; Sugeng, A J; Kelly, M D; Lothrop, N; Klimecki, W; Wilkinson, S T; Loh, M

    2014-05-01

    Mine tailings are a source of metal exposures in many rural communities. Multiple air samples are necessary to assess the extent of exposures and factors contributing to these exposures. However, air sampling equipment is costly and requires trained personnel to obtain measurements, limiting the number of samples that can be collected. Simple, low-cost methods are needed to allow for increased sample collection. The objective of our study was to assess if dust fall filters can serve as passive air samplers and be used to characterize potential exposures in a community near contaminated mine tailings. We placed filters in cylinders, concurrently with active indoor air samplers, in 10 occupied homes. We calculated an estimated flow rate by dividing the mass on each dust fall filter by the bulk air concentration and the sampling duration. The mean estimated flow rate for dust fall filters was significantly different during sampling periods with precipitation. The estimated flow rate was used to estimate metal concentration in the air of these homes, as well as in 31 additional homes in another rural community impacted by contaminated mine tailings. The estimated air concentrations had a significant linear association with the measured air concentrations for beryllium, manganese and arsenic (p < 0.05), whose primary source in indoor air is resuspended soil from outdoors. In the second rural community, our estimated metal concentrations in air were comparable to active air sampling measurements taken previously. This passive air sampler is a simple low-cost method to assess potential exposures near contaminated mining sites.

  4. [Evaluation of working environment in the textile industry. IV. Dust concentration in the air of the flax spinning and weaving plants].

    PubMed

    Gościcki, J; Wiecek, E; Matecki, W; Bielichowska, G

    1980-01-01

    Evaluation of dust concentration in the air of spinning and weaving rooms was made by gravimetric sampling of dust in 3 flax plants, where short flax fibres (flax--tow) and long flax fibres were manufactured. Besides, the dispersion of dusts and concentration of free silica were determined. The highest concentration of dust (10 mg/m3) was found in hackling room, mixing mill, and the one where spreading machines are operated, while in the carding room it was - 7.0 mg/m3. In other shops the concentration was - 5.5 mg/m3. The dust in the air of spinning rooms contained 2.3% of free silica and 53% of its particles were smaller than 5 micrometers. In the weaving rooms it contained 1.6% of free silica and 57% particles were smaller than 5 micrometers. The geometric mean of dust concentration higher than MAC for vegetable dusts (4 mg/m3) was found in hackling mill, mixing mill and the one where spreading machines are operated.

  5. Comparison of direct and indirect methods of measuring airborne chrysotile fibre concentration.

    PubMed

    Eypert-Blaison, Celine; Veissiere, Sylvie; Rastoix, Olivier; Kauffer, Edmond

    2010-01-01

    Transmission electron microscopy observations most frequently form a basis for estimating asbestos fibre concentration in the environment and in buildings with asbestos-containing materials. Sampled fibres can be transferred to microscope grids by applying either a direct [ISO (1995) Draft International ISO/DIS 10312. Ambient air. Determination of asbestos fibres. Direct transfer transmission electron microscopy procedure. Geneva, Switzerland: International Standardization Organization] or an indirect [AFNOR (1996) Détermination de la concentration en fibres d'amiante par microscopie électronique à transmission-Méthode indirecte. Cedex, France: AFNOR, p. 42; ISO (1997) Draft International ISO/DIS 13794. Ambient air. Determination of asbestos fibres. Indirect-transfer transmission electron microscopy procedure. Geneva, Switzerland: International Standardization Organization] method. In the latter case, ISO Standard 13794 recommends filtering calcination residues either on a polycarbonate (PC) filter (PC indirect method) or on a cellulose ester (CE) membrane (CE indirect method). The PC indirect method requires that fibres deposited on a PC filter be covered by a carbon layer, whereas in the CE indirect method, the CE membrane has to be directly processed using a method described in ISO Standard 10312. The purpose of this study was to compare results obtained using, on the one hand, direct preparation methods and, on the other hand, PC indirect or CE indirect methods, for counting asbestos fibres deposited on filters as a result of liquid filtration or air sampling. In direct method-based preparation, we observed that an etching time of 6-14 min does not affect the measured densities, except for fibres <1 microm deposited by liquid filtration. Moreover, in all cases, the direct method gives higher densities than the PC indirect method because of possible fibre disappearance when using the carbon evaporator implemented in the PC indirect method. The CE membrane

  6. Saharan dust aerosol over the central Mediterranean Sea: PM10 chemical composition and concentration versus optical columnar measurements

    NASA Astrophysics Data System (ADS)

    Marconi, M.; Sferlazzo, D. M.; Becagli, S.; Bommarito, C.; Calzolai, G.; Chiari, M.; di Sarra, A.; Ghedini, C.; Gómez-Amo, J. L.; Lucarelli, F.; Meloni, D.; Monteleone, F.; Nava, S.; Pace, G.; Piacentino, S.; Rugi, F.; Severi, M.; Traversi, R.; Udisti, R.

    2014-02-01

    This study aims to determine the mineral contribution to PM10 in the central Mediterranean Sea, based on 7 yr of daily PM10 samplings made on the island of Lampedusa (35.5° N, 12.6° E). The chemical composition of the PM10 samples was determined by ion chromatography for the main ions, and, on selected samples, by particle-induced X-ray emission (PIXE) for the total content of crustal markers. Aerosol optical depth measurements were carried out in parallel to the PM10 sampling. The average PM10 concentration at Lampedusa over the period June 2004-December 2010 is 31.5 μg m-3, with low interannual variability. The annual means are below the EU annual standard for PM10, but 9.9% of the total number of daily data exceeds the daily threshold value established by the European Commission for PM (50 μg m-3, European Community, EC/30/1999). The Saharan dust contribution to PM10 was derived by calculating the contribution of Al, Si, Fe, Ti, non-sea-salt (nss) Ca, nssNa, and nssK oxides in samples in which PIXE data were available. Cases in which crustal content exceeded the 75th percentile of the crustal oxide content distribution were identified as elevated dust events. Using this threshold, we obtained 175 events. Fifty-five elevated dust events (31.6%) displayed PM10 higher than 50 μg m-3, with dust contributing by 33% on average. The crustal contribution to PM10 has an annual average value of 5.42 μg m-3, and reaches a value as high as 67.9 μg m-3 (corresponding to 49% of PM10) during an intense Saharan dust event. The crustal content estimated from a single tracer, such as Al or Ca, is in good agreement with the one calculated as the sum of the metal oxides. Conversely, larger crustal contents are derived by applying the EU guidelines for demonstration and subtraction of exceedances in PM10 levels due to high background of natural aerosol. The crustal aerosol amount and contribution to PM10 showed a very small seasonal dependence; conversely, the dust columnar

  7. Effect of filtration velocity and dust concentration on cake formation and filter operation in a pilot scale jet pulsed bag filter.

    PubMed

    Saleem, Mahmood; Krammer, Gernot

    2007-06-18

    Bag filters are used for the removal of fine solid particles from process gases. Thus, understanding the filter cake build up and its properties is a subject of interest. The filter cakes properties may depend on many factors like, for example, filtration velocity and dust concentration. The effect of dust concentration and filtration velocity on filtration time, specific cake resistance and mean cake density is investigated in a pilot scale jet pulsed bag filter. An in situ optical system is used to measure cake thickness distributions on the filter surface. Additionally, the operation is simulated using a one-dimensional model and results are compared with experiments. The experimental results indicate that cake density and specific resistance increase with increasing velocity at constant dust concentration. The effect of dust concentration on filter cake density and specific resistance is small.

  8. 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.

  9. patterns of dust transport to the Grand Canyon

    NASA Astrophysics Data System (ADS)

    de P. Vasconcelos, Luis A.; Kahl, Jonathan D. W.; Liu, Desong; Macias, Edward S.; White, Warren H.

    Dust particles in the 2.5 µm to 15 µm diameter range contribute to regional haze that sometimes impairs visibility at the Grand Canyon and other National Parks in the southwestern U.S. The proportion of airborne dust that is attributable to land modification is unknown, but can be expected to increase as a consequence of the region's rapid population growth. This note examines the upwind histories of air masses bringing high coarse-particle concentrations to the Grand Canyon over a five-year monitoring period. Although arid and semi-arid lands extend in all directions, and the fastest airflows generally have a northerly component, high dust concentrations are most common in air arriving from the southwest, where development has been concentrated. This empirical association suggests that the expansion of suburban and agricultural lands is raising dust levels at the Grand Canyon.

  10. The contribution of Saharan dust in PM(10) concentration levels in Anatolian Peninsula of Turkey.

    PubMed

    Kabatas, B; Unal, A; Pierce, R B; Kindap, T; Pozzoli, L

    2014-08-01

    Sahara-originated dust is the most significant natural source of particulate matter; however, this contribution is still unclear in the Eastern Mediterranean especially in Western Turkey, where significant industrial sources and metropolitan areas are located. The Real-time Air Quality Modeling System (RAQMS) is utilized to explore the possible effects of Saharan dust on high levels of PM10 measured in Turkey. RAQMS model is compared with 118-air quality stations distributed throughout Turkey (81 cities) for April 2008. MODIS aerosol product (MOD04 for Terra and MYD04 for Aqua) is used to see columnar aerosol loading of the atmosphere at 550 nm (Aerosol optical depth (AOD) values found to be between 0.6 and 0.8 during the episode). High-resolution vertical profiles of clouds and aerosols are provided from CALIOP, on board of CALISPO satellite. The results suggest a significant contribution of Sahara dust to high levels of PM10 in Turkey with RAQMS and in situ time series showing similar patterns. The two data sets are found to be in agreement with a correlation of 0.87.

  11. Dioxin furan blood lipid and attic dust concentrations in populations living near four wood treatment facilities in the United States.

    PubMed

    Feng, L; Wu, C; Tam, L; Sutherland, A J; Clark, J J; Rosenfeld, P E

    2011-01-01

    To evaluate historical exposure from wood treatment facilities, attic dust samples were collected from residential structures and blood samples were collected from current and past residents of four communities surrounding wood treatment facilities throughout the United States. The pattern of dioxin/furan congeners detected in both attic dust and blood samples was found to be consistent with exposure to contaminants generated during the wood treatment process. Levels in the U.S. population of 2,3,7,8-tetrachloro-p-dibenzodioxin toxic equivalents (2,3,7,8-TCDD TEQs) for all 17 carcinogenic dioxin/furan congeners as well as octa-chlorinated dibenzo-p-dioxin (OCDD) adjusted to its TEQ value and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (1,2,3,4,6,7,8-HpCDD) adjusted to its TEQ value were compared to the TEQ levels in the combined data set for all four communities and in the data sets for each individual community. TEQ concentrations in these communities were found to be significantly greater than in the general U.S. population. The levels of dioxins in attic dust were compared to the U.S. Environmental Protection Agency's regional screening levels and found to far exceed the levels that are regarded as safe for the general population. These findings reveal that a very significant potential for contaminant-related health risks exists in communities surrounding wood treatment facilities.

  12. Pulmonary Toxicity Studies of Lunar Dusts in Rodents

    NASA Technical Reports Server (NTRS)

    Lam, Chiu-wing; James, John T.; Taylor, Larry

    2008-01-01

    NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. NASA established the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Because the toxicity of lunar dust is not known, LADTAG has recommended investigating its toxicity in the lungs of laboratory animals. After receiving this recommendation, NASA directed the JSC Toxicology Laboratory to determine the pulmonary toxicity of lunar dust in exposed rodents. The rodent pulmonary toxicity studies proposed here are the same as those proposed by the LADTAG. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal instillation (ITI). This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. We succeeded in completing an ITI study on JSC-1 lunar dust simulant in mice (Lam et al., Inhalation Toxicology 14:901-916, 2002, and Inhalation Toxicology 14: 917-928, 2002), and have conducted a pilot ITI study to examine the acute toxicity of an Apollo lunar (highland) dust sample. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies have been planned to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The ITI results will also be

  13. The use of an experimental room for monitoring of airborne concentrations of microorganisms, glass fibers, and total particles

    SciTech Connect

    Buttner, M.P.; Stetzenbach, L.D.

    1996-12-31

    An experimental room was used as a microcosm for studies of airborne particles and microorganisms in indoor environments. The interior of the room measures 4 by 4 by 2.2 m high and has a hardwood floor and the walls and ceiling are sheetrocked and coated with interior latex paint. Exterior walls are 11.4-cm thick plywood panels consisting of two outer sections of plywood insulated with fiber glass batts. The ceiling is of similar construction with 17.1-cm thick panels. Attached to the room entrance is an anteroom equipped with a HEPA-filtered air shower to reduce mixing of air resulting from entering and exiting during experiments. The room is equipped with a computer-controlled heating, ventilation, and cooling system. Temperature, relative humidity, air flow, and room pressure can be continuously monitored by probes located in the room and air handling system components. Several research projects have been conducted using this room including monitoring the potential for airborne glass fibers released from rigid fibrous ductboard, comparisons of commercially available samplers for monitoring of airborne fungal spores, and a study on the efficacy of vacuum bags to minimize dispersal of particles, including fungal spores from fungal-contaminated carpet. During studies designed to monitor airborne fiberglass, air samples were taken in the room serviced by new rigid fibrous glass ductwork, and the results were compared to those obtained in the room with bare metal ductwork installed. Monitoring of airborne fungal spores using the Andersen six-stage sampler, the high flow Spiral Biotech sampler, the Biotest RCS Plus sampler, and the Burkard spore trap sampler was performed following the release of Penicillium spores into the room through the supply register. Dispersal of carpet-associated particles and fungal spores was measured after vacuuming using conventional cellulose vacuum bags in comparison to recently developed bags.

  14. Retrieval of Atmospheric CO2 Concentration above Clouds and Cloud Top Pressure from Airborne Lidar Measurements during ASCENDS Science Campaigns

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ramanathan, A. K.; Rodriguez, M.; Allan, G. R.; Hasselbrack, W. E.; Abshire, J. B.; Riris, H.; Kawa, S. R.

    2014-12-01

    NASA Goddard is developing an integrated-path, differential absorption (IPDA) lidar approach to measure atmospheric CO2 concentrations from space as a candidate for NASA's ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission. The approach uses pulsed lasers to measure both CO2 and O2 absorption simultaneously in the vertical path to the surface at a number of wavelengths across a CO2 line at 1572.335 nm and an O2 line doublet near 764.7 nm. Measurements of time-resolved laser backscatter profiles from the atmosphere allow the technique to estimate column CO2 and O2 number density and range to cloud tops in addition to those to the ground. This allows retrievals of CO2 column above clouds and cloud top pressure, and all-sky measurement capability from space. This additional information can be used to evaluate atmospheric transport processes and other remote sensing carbon data in the free atmosphere, improve carbon data assimilation in models and help global and regional carbon flux estimates. We show some preliminary results of this capability using airborne lidar measurements from the summers of 2011 and 2014 ASCENDS science campaigns. These show simultaneous retrievals of CO2 and O2 column densities for laser returns from low-level marine stratus clouds in the west coast of California. This demonstrates the supplemental capability of the future space carbon mission to measure CO2 above clouds, which is valuable particularly for the areas with persistent cloud covers, e.g, tropical ITCZ, west coasts of continents with marine layered clouds and southern ocean with highest occurrence of low-level clouds, where underneath carbon cycles are active but passive remote sensing techniques using the reflected short wave sunlight are unable to measure accurately due to cloud scattering effect. We exercise cloud top pressure retrieval from O2 absorption measurements during the flights over the low-level marine stratus cloud decks, which is one of

  15. Concentrations of trace elements and compounds in the airborne suspended particulate matter in Cleveland, Ohio, from August 1971 to August 1972 and their dependence on wind direction: Complete data listing and concentration roses

    NASA Technical Reports Server (NTRS)

    King, R. B.; Neustadter, H. E.

    1976-01-01

    Concentrations of 75 chemical constituents in the airborne particulate matter were measured in Cleveland, Ohio during 1971 and 1972. Daily values, maxima, geometric means and their standard deviations covering a 1-year period (45 to 50 sampling days) at each of 16 sites are presented on microfiche for 60 elements, and for a lesser number of days for 10 polycyclic aromatic hydrocarbon compounds (PAH), the aliphatic hydrocarbon compounds (AH) as a group and carbon. In addition, concentration roses showing directional properties are presented for 39 elements, 10 PAH and the AH as a group. The elements (except carbon) are shown both in terms of concentration and percentage of the suspended particulate matter.

  16. Optimization of regimes for the feed of highly concentrated culm-anthracite coal dust for burning in a TPP-210A boiler

    SciTech Connect

    L.V. Golyshev; G.A. Dovgoteles

    2007-05-15

    Results are presented for regime adjustment of feed systems for a TPP-210A boiler for the burning of highly concentrated culm-anthracite coal dust. As compared with nonoptimal regimes, optimal regimes of high-concentration-feed systems improve the economy of the boiler by 1.7% on average.

  17. 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

  18. Comparative occupational exposures to formaldehyde released from inhaled wood product dusts versus that in vapor form.

    PubMed

    Gosselin, Nathalie H; Brunet, Robert C; Carrier, Gaétan

    2003-05-01

    Particle boards and other wood boards are usually made with formaldehyde-based resins. Woodworkers are thus exposed to formaldehyde in vapor form as well as from airborne dust once it enters their respiratory tract. These workers remain exposed to formaldehyde released from the dust still present in their upper respiratory tract, even after their work shift. In assessing the risk associated with formaldehyde exposure, one needs to consider the relative importance of these two sources of exposure. This study proposes two kinetic models to estimate and compare the exposures. For various exposure scenarios, one model predicts the amount of formaldehyde absorbed from the ambient vapor form and the other predicts the amount absorbed by the respiratory tract upon its release from wood product dust. Model parameters are determined using data from published studies. Based on a daily work shift of 8 hr, with a dust concentration in air of 5 mg/m(3) and a formaldehyde concentration bound to dust of 9 microg/mg, model simulations predict that the amount of absorbed formaldehyde released from wood dust is approximately 1/100 of the amount absorbed from the ambient vapor form at a concentration level of 0.38 mg/m(3) (0.3 ppm). Since the formaldehyde concentration in wood dust used above is much higher than usually observed while the dust and vapor form formaldehyde concentrations are of the order of acceptable upper values, these results indicate that the formaldehyde exposure from wood dust is comparatively negligible.

  19. Tracing geogenic and anthropogenic sources in urban dusts: Insights from lead isotopes

    NASA Astrophysics Data System (ADS)

    Del Rio-Salas, R.; Ruiz, J.; De la O-Villanueva, M.; Valencia-Moreno, M.; Moreno-Rodríguez, V.; Gómez-Alvarez, A.; Grijalva, T.; Mendivil, H.; Paz-Moreno, F.; Meza-Figueroa, D.

    2012-12-01

    Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechanism, surface soil samples were collected, as well as wind-transported dust trapped at 1 and 2 m height at seven different locations including residential, industrial, high-traffic and rural sites. Samples of dust deposited on roofs from 24 schools were also obtained and analyzed for Pb isotope ratios. Spatial distribution of Pb of airborne and sedimented dust suggests a process dominated by re-suspension/sedimentation, which was controlled by erosion, traffic and topography of the urban area. Anthropogenic lead input in the city grades outward the urban zone toward geogenic values. Our results shows that Pb-isotopic signatures of leaded gasoline are imprinted in dust sedimented on roofs. Considering that leaded-gasoline has not been in use in Mexico since two decades ago, this signature shows not only a Pb-legacy in soil, but also a re-suspension process affecting air column below 3 m in height. The combination of the 207Pb/206Pb data of the surrounding rocks and urban dust, reveal three well-defined zones with remarkable anthropogenic influence, which correspond to the oldest urban sectors. This work highlights the importance of spatial characterization of metals in particles suspended below a height of 3 m of the airborne column, a fact that should be considered to identify exposure paths to humans and the potential risks. Lead isotope signatures allowed the identification of geogenic and anthropogenic emission sources for dust, a matter that deserves consideration in the efforts to control airborne metal emissions.

  20. Concentration of Bacterial Aerosols Associated with Particles: Observations at a Southwestern Coastal Site of Japan in the Spring of 2013-2014

    NASA Astrophysics Data System (ADS)

    Murata, K.; Zhang, D.

    2015-12-01

    Airborne bacteria are the major group of bioaerosols in the air and are considered to have important climate effects by acting as ice nuclei. To investigate the dependence of bacteria on particles in the air, we enumerated bacterial cells in size-segregated airborne particle samples that were collected at a rural seaside site on the southwestern coast of Japan during dust and non-dust periods in the spring of 2013-2014. Proportion of particle-attached bacteria was 75-84% of total airborne bacterial concentration during dust periods and 27-76% during non-dust periods, both of which were equal to approximately 12% of >1 µm aerosol particle concentrations. The concentration of particle-attached bacteria was 3.2 times higher during dust periods, compared with that during non-dust periods. The viability, which is referring to the ratio of viable cells to total cells, of particle-attached bacteria was 33-82% during dust periods and 45-98% during non-dust periods. The predominance of particle-associated viable/non-viable bacteria during dust periods demonstrates a potential of bacteria to cooperate with dust in influencing the climate, ecosystems, and health where they arrive.

  1. Temporal variability of mineral dust in southern Tunisia: analysis of 2 years of PM10 concentration, aerosol optical depth, and meteorology monitoring

    NASA Astrophysics Data System (ADS)

    Bouet, Christel; Taieb Labiadh, Mohamed; Bergametti, Gilles; Rajot, Jean Louis; Marticorena, Béatrice; Sekrafi, Saâd; Ltifi, Mohsen; Féron, Anaïs; des Tureaux, Thierry Henry

    2016-04-01

    The south of Tunisia is a region very prone to wind erosion. During the last decades, changes in soil management have led to an increase in wind erosion. In February 2013, a ground-based station dedicated to the monitoring of mineral dust (that can be seen in this region as a proxy of the erosion of soils by wind) was installed at the Institut des Régions Arides (IRA) of Médenine (Tunisia) to document the temporal variability of mineral dust concentrations. This station allows continuous measurements of surface PM10 concentration (TEOM™), aerosol optical depth (CIMEL sunphotometer), and total atmospheric deposition of insoluble dust (CARAGA automatic sampler). The simultaneous monitoring of meteorological parameters (wind speed and direction, relative humidity, air temperature, atmospheric pressure, and precipitations) allows to analyse the factors controlling the variations of mineral dust concentration from the sub-daily to the annual scale. The results from the two first years of measurements of PM10 concentration are presented and discussed. In average on year 2014, PM10 concentration is 56 μg m-3. However, mineral dust concentration highly varies throughout the year: very high PM10 concentrations (up to 1,000 μg m-3 in daily mean) are frequently observed during wintertime and springtime, hardly ever in summer. These episodes of high PM10 concentration (when daily average PM10 concentration is higher than 240 μg m-3) sometimes last several days. By combining local meteorological data, air-masses trajectories, sunphotometer measurements, and satellite imagery, the part of the high PM10concentration due to local emissions and those linked to an advection of dusty air masses by medium and long range transport from the Sahara desert is quantified.

  2. MAP3S/RAINE modeling abstracts, 1980. [Concise descriptions of models and availability for calculation of airborne concentration of sulfur dioxide and sulfate

    SciTech Connect

    Michael, P.

    1980-07-01

    The MultiState Atmospheric Power Production Pollution Study (MAP3S) has produced as a primary research output a number of numerical models for the calculation of airborne concentrations of sulfur dioxide and sulfate resulting from anthropogenic sources. Concise descriptions of these models, and of related modeling developments, are collected in this report. For each model, or model component, there is included a listing of the authors, a summary of what it is the model calculates and the method used, a list of references, and a statement of availability.

  3. Long-Range Atmospheric Transport of Soil Dust from Asia to the Tropical North Pacific: Temporal Variability

    NASA Astrophysics Data System (ADS)

    Duce, R. A.; Unni, C. K.; Ray, B. J.; Prospero, J. M.; Merrill, J. T.

    1980-09-01

    The concentration of airborne soil dust at Enewetak Atoll (11 degrees N, 162 degrees E) in April 1979 was 2.3 micrograms per cubic meter but decreased steadily to 0.02 microgram per cubic meter over the next 5 months. The spring dust is probably derived from China; its deposition rate (~ 0.3 millimeter per 1000 years) suggests that it may be a significant contributor to the deep-sea sediments of the North Pacific.

  4. Long-range atmospheric transport of soil dust from Asia to the tropical north pacific: temporal variability.

    PubMed

    Duce, R A; Unni, C K; Ray, B J; Prospero, J M; Merrill, J T

    1980-09-26

    The concentration of airborne soil dust at Enewetak Atoll(11 degrees N, 162 degrees E) in April 1979 was 2.3 micrograms per cubic meter but decreased steadily to 0.02 microgram per cubic meter over the next 5 months. The spring dust is probably derived from China; its deposition rate ( approximately 0.3 millimeter per 1000 years) suggests that it may be a significant contributor to the deep-sea sediments of the North Pacific.

  5. Effect of plateout, air motion and dust removal on radon decay product concentration in a simulated residence.

    PubMed

    Rudnick, S N; Hinds, W C; Maher, E F; First, M W

    1983-08-01

    The effectiveness of increased air motion and dust removal in reducing radon decay product concentration in residences subject to radon intrusion was evaluated in a 78-m3 room under steady-state conditions for air infiltration rates between 0.2 and 0.9 air changes per hour. Room-size, portable electrostatic precipitators and high-efficiency fibrous filters were tested as typical residential air cleaning devices; a portable box fan and a ceiling fan were employed as typical residential air movers. Reductions in working levels of 40-90% were found. The fate of radon decay products, with and without mixing fans, was determined by direct measurement. When mixing fans were used, most of the nonairborne potential alpha-energy was plated out on the room surfaces; less than 10% was deposited on the fan blades or housing. Results were compared to a mathematical model based on well-mixed room air, and good agreement was obtained.

  6. Reducing float coal dust

    PubMed Central

    Patts, J.R.; Colinet, J.F.; Janisko, S.J.; Barone, T.L.; Patts, L.D.

    2016-01-01

    Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal dust levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal dust levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. PMID:28018004

  7. Coal dust contiguity-induced changes in the concentration of TNF- and NF- B p65 on the ocular surface

    SciTech Connect

    Sun, Z.Y.; Hong, J.; Liu, Z.Y.; Jin, X.D.; Gu, C.H.

    2009-07-01

    To observe the influence of coal dust on ocular surface of coal miners and rabbits with coal dust contiguity on expression TNF- and NF- Bp65 and dry eye occurrence. Expression TNF- and NF- Bp65 in ocular surface were determined. Results showed tear production, BUT and lysozyme decreased for coal miners and rabbits with coal dust contiguity. Coal dust exposure was linked to development of xerophthalmia, and induced a higher expression of NF- B p65 and TNF- perhaps as a mechanism to resist coal dust ocular surface injury.

  8. Metals in dust fractions emitted at mechanical workstations.

    PubMed

    Kondej, Dorota; Gawęda, Ewa

    2012-01-01

    Workers at metal machining workstations are exposed to airborne dust particles containing metals and their compounds. Their harmful impact on the workers' health depends on both their chemical composition and their distribution. The aim of this study was to determine the content of metals in dust fractions emitted in the process of mechanical machining of products made of brass, steel and cast iron. Samples taken during grinding, turning and drilling were tested. The concentration of metals in dust fractions was determined with atomic absorption spectrometry. The content of iron, manganese, chromium, zinc, lead, copper and nickel in the dust fractions was highly differentiated depending on the size of the particles, the material and the processes used.

  9. Impact of dust filter installation in ironworks and construction on brownfield area on the toxic metal concentration in street and house dust (Celje, Slovenia).

    PubMed

    Zibret, Gorazd

    2012-05-01

    This article presents the impact of the ecological investment in ironworks (dust filter installation) and construction works at a highly contaminated brownfield site on the chemical composition of household dust (HD) and street sediment (SS) in Celje, Slovenia. The evaluation is based on two sampling campaigns: the first was undertaken 1 month before the ecological investment became operational and the second 3 years later. The results show that dust filter installations reduced the content of Co, Cr, Fe, Mn, Mo, W and Zn on average by 58% in HD and by 51% in SS. No reduction was observed at sampling points in the upwind direction from the ironworks. By contrast, the impact of the construction works on the highly contaminated brownfield site was detected by a significant increase (on average by 37%) of elements connected to the brownfield contamination in SS. Such increase was not detected in HD.

  10. Application of neutral electrolyzed water spray for reducing dust levels in a layer breeding house.

    PubMed

    Zheng, Weichao; Li, Baoming; Cao, Wei; Zhang, Guoqiang; Yang, Zhanyong

    2012-11-01

    Reducing airborne dust is an essential process for improving hen housing environment. Dust reduction effects of neutral electrolyzed water (pH 8.2) spray were investigated in a commercial tunnel-ventilated layer breeding house during production in northern China. A multipoint sampler was used to measure airborne dust concentration to study the dust reduction effects and distribution in the house. Compared with the control treatment (without spray), airborne dust level was reduced 34% in the 3 hr after spraying 216 mL m(-2) neutral electrolyzed water in the breeding house. The dust concentration was significantly higher during the periods of feed distribution (1.13 +/- 0.13 mg m(-3)) and artificial insemination (0.72 +/- 0.13 mg m(-3)) compared with after spray (0.47 +/- 0.09 mg m(-3)) and during lights-off period (0.29 +/- 0.08 mg m(-3)) in the three consecutive testing days (P <0.05). The experimental cage area was divided into four zones along the length of the house, with zone 1 nearest to the evaporative cooling pad and zone 4 nearest to the fans. The air temperature, relative humidity, airflow rate, and dust concentration were measured at the sampling points of the four zones in 3 consecutive days and mortality of the birds for the duration of a month were investigated. The results showed that the air temperature, airflow rate, dust concentration, and number of dead birds increase from zone 1 to zone 4 in the tunnel-ventilated layer breeding house.

  11. Evaluation of the area factor used in the RESRAD code for the estimation of airborne contaminant concentrations of finite area sources

    SciTech Connect

    Chang, Y.S.; Yu, C.; Wang, S.K.

    1998-07-01

    The area factor is used in the RESRAD code to estimate the airborne contaminant concentrations for a finite area of contaminated soils. The area factor model used in RESRAD version 5.70 and earlier (referred to as the old area factor) was a simple, but conservative, mixing model that tended to overestimate the airborne concentrations of radionuclide contaminants. An improved and more realistic model for the area factor (referred to here as the new area factor) is described in this report. The new area factor model is designed to reflect site-specific soil characteristics and meteorological conditions. The site-specific parameters considered include the size of the source area, average particle diameter, and average wind speed. Other site-specific parameters (particle density, atmospheric stability, raindrop diameter, and annual precipitation rate) were assumed to be constant. The model uses the Gaussian plume model combined with contaminant removal processes, such as dry and wet deposition of particulates. Area factors estimated with the new model are compared with old area factors that were based on the simple mixing model. In addition, sensitivity analyses are conducted for parameters assumed to be constant. The new area factor model has been incorporated into RESRAD version 5.75 and later.

  12. A STUDY OF FISCHER 344 RATS EXPOSED TO SILICA DUST FOR SIX MONTHS AT CONCENTRATIONS OF 0, 2, 10 OR 20 MG / M3.

    SciTech Connect

    KUTZMAN,R.S.

    1984-02-01

    The major objective of this study was to relate the results of a series of functional tests to the compositional and structural alterations in the rat lung induced by subchronic exposure to silica dust. Fischer-344 rats were exposed for 6 hours/day, 5 days/week for 6 months to either 0, 2, 10, or 20 mg SiO{sub 2}/m{sup 3}. The general appearance of the exposed rats was not different from that of the controls. Interestingly, female rats exposed to silica dust, at all tested concentrations, gained more weight than the controls. The lung weight and the lung-to-body weight ratio was greater in the male rats exposed to the highest concentration of silica dust.

  13. Increase in African dust flux at the onset of commercial agriculture in the Sahel region.

    PubMed

    Mulitza, Stefan; Heslop, David; Pittauerova, Daniela; Fischer, Helmut W; Meyer, Inka; Stuut, Jan-Berend; Zabel, Matthias; Mollenhauer, Gesine; Collins, James A; Kuhnert, Henning; Schulz, Michael

    2010-07-08

    The Sahara Desert is the largest source of mineral dust in the world. Emissions of African dust increased sharply in the early 1970s (ref. 2), a change that has been attributed mainly to drought in the Sahara/Sahel region caused by changes in the global distribution of sea surface temperature. The human contribution to land degradation and dust mobilization in this region remains poorly understood, owing to the paucity of data that would allow the identification of long-term trends in desertification. Direct measurements of airborne African dust concentrations only became available in the mid-1960s from a station on Barbados and subsequently from satellite imagery since the late 1970s: they do not cover the onset of commercial agriculture in the Sahel region approximately 170 years ago. Here we construct a 3,200-year record of dust deposition off northwest Africa by investigating the chemistry and grain-size distribution of terrigenous sediments deposited at a marine site located directly under the West African dust plume. With the help of our dust record and a proxy record for West African precipitation we find that, on the century scale, dust deposition is related to precipitation in tropical West Africa until the seventeenth century. At the beginning of the nineteenth century, a sharp increase in dust deposition parallels the advent of commercial agriculture in the Sahel region. Our findings suggest that human-induced dust emissions from the Sahel region have contributed to the atmospheric dust load for about 200 years.

  14. Modeling of dust deposition in central Asia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The deposition of dust particles has a significant influence on the global bio-geochemical cycle. Currently, the lack of spatiotemporal data creates great uncertainty in estimating the global dust budget. To improve our understanding of the fate, transport and cycling of airborne dust, there is a ne...

  15. The concentrations of phthalates in settled dust in Bulgarian homes in relation to building characteristic and cleaning habits in the family

    NASA Astrophysics Data System (ADS)

    Kolarik, Barbara; Bornehag, Carl-Gustaf; Naydenov, Kiril; Sundell, Jan; Stavova, Petra; Nielsen, Ole Faurskov

    Phthalate esters are chemical compounds with a broad range of applications. Recently, we have shown that significantly higher dust concentration of di(2-ethylhexyl) phthalate (DEHP) was found in Bulgarian homes of children with asthma or allergies compared to healthy children. The concentration of DEHP was found to be significantly associated with wheezing in the last 12 months as reported by parents. The objective of the current study was to examine the associations between concentrations of phthalates in settled dust collected in Bulgarian homes and building characteristics and cleaning habits. Dust samples from the child's bedroom were collected in 177 homes and analysed for the content of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBzP), di- n-octyl phthalate (DnOP) and DEHP. Information on building characteristics and family habits were collected from parental reports in questionnaires and from inspectors' observations in the homes. Significantly higher concentrations of BBzP, DEHP and DnOP in indoor dust were found in homes where polishing agents were used, compared to homes where such products were not used. The highest concentrations of DEHP, BBzP and DnOP were found in homes with the combination of a low frequency of dusting and the use of polish. There was no difference in phthalate concentrations between inspector-observed balatum flooring (PVC or linoleum) and wood flooring as well as between PVC, as determined by Raman spectra, and wood flooring. However, in a sub-group of homes with no use of polish, the concentration of DEHP was higher in homes with inspector-observed balatum compared with wood flooring but the difference was not significant may be due to a too small sample size.

  16. An assessment of the surface longwave direct radiative effect of airborne dust in Zhangye, China, during the Asian Monsoon Years field experiment (2008)

    NASA Astrophysics Data System (ADS)

    Hansell, Richard A.; Tsay, Si-Chee; Hsu, N. Christina; Ji, Qiang; Bell, Shaun W.; Holben, Brent N.; Welton, Ellsworth J.; Roush, Ted L.; Zhang, W.; Huang, J.; Li, Zhanqing; Chen, H.

    2012-08-01

    In April-June 2008, NASA Goddard's ground-based mobile laboratories (SMART-COMMIT) were deployed to Zhangye China (39.0°N; 101°W) to support the Asian Monsoon Years field experiment and the East Asian Study of Tropospheric Aerosols and Impact on Regional Climate. One of the primary objectives at Zhangye, a semi-arid region located between the Taklimakan and Gobi Deserts, was to capture and characterize dust aerosols near the source and to quantify their direct radiative effects (DRE). A regional dust optical model was constructed by combining previously measured soil mineralogy data at Zhangye with COMMIT's particle microphysical measurements. During a 2-week period of heightened dust activity, retrieved longwave (LW) aerosol optical thickness (τ) from SMART's Atmospheric Emitted Radiance Interferometer was used in the Fu-Liou radiative transfer model to derive LW instantaneous DRE (DRELW) at the surface, top of atmosphere, and heating rate profiles for cloud-free conditions. Conservatively, surface instantaneous DRELW and LW forcing efficiency range from about 2-20 Wm-2 and 31-35 Wm-2τ-1 (0 ≤ τ ≤ 0.83), respectively. The significance of DRELWrelative to its shortwave counterpart was estimated to be between 51 and 58%, but of opposite sign, partly compensating shortwave surface cooling. Compared to Saharan dust observed during the NAMMA-2006 field experiment at Cape Verde, dust LW forcing efficiency for this study was found to be a factor of two larger stemming from differences in environmental and surface conditions, aerosol absorption, and Zhangye's close proximity to major desert sources. Relative to observed and modeled ranges in surface DRELW for clouds (˜30-80 Wm-2) and greenhouse gases (˜2 Wm-2), this study's upper range in DRELW represents a significant perturbation to the climate system with important implications for better understanding regional changes in surface temperatures and moisture budgets.

  17. Impacts of Asian dust events on atmospheric fungal communities

    NASA Astrophysics Data System (ADS)

    Jeon, Eun Mi; Kim, Yong Pyo; Jeong, Kweon; Kim, Ik Soo; Eom, Suk Won; Choi, Young Zoo; Ka, Jong-Ok

    2013-12-01

    The composition of atmospheric fungi in Seoul during Asian dust events were assessed by culturing and by molecular methods such as mold specific quantitative PCR (MSQPCR) and internal transcribed spacer cloning (ITS cloning). Culturable fungal concentrations in the air were monitored from May 2008 to July 2011 and 3 pairs of ITS clone libraries, one during Asian dust (AD) day and the other during the adjacent non Asian dust (NAD) day for each pair, were constructed after direct DNA extraction from total suspended particles (TSP) samples. In addition, six aeroallergenic fungi in the atmosphere were also assessed by MSQPCR from October, 2009 to November, 2011. The levels of the airborne culturable fungal concentrations during AD days was significantly higher than that of NAD days (P < 0.005). In addition, the correlation of culturable fungal concentrations with particulate matters equal to or less than 10 μm in aerodynamic diameter (PM10) concentrations was observed to be high (0.775) for the AD days while correlation coefficients of PM10 as well as other particulate parameters with airborne fungal concentrations were significantly negative for the NAD days during intensive monitoring periods (May to June, 2008). It was found that during AD days several airborne allergenic fungal levels measured with MSQPCR increased up to 5-12 times depending on the species. Comparison of AD vs. NAD clones showed significant differences (P < 0.05) in all three cases using libshuff. In addition, high proportions of uncultured soil fungus isolated from semi-arid regions were observed only in AD clone libraries. Thus, it was concluded that AD impacts not only airborne fungal concentrations but also fungal communities.

  18. Concentrations of Semivolatile Organic Compounds Associated with African Dust Air Masses in Mali, Cape Verde, Trinidad and Tobago, and the U.S. Virgin Islands, 2001-2008

    USGS Publications Warehouse

    Garrison, Virginia H.; Foreman, William T.; Genualdi, Susan A.; Majewski, Michael S.; Mohammed, Azad; Simonich, Staci Massey

    2011-01-01

    Every year, billions of tons of fine particles are eroded from the surface of the Sahara Desert and the Sahel of West Africa, lifted into the atmosphere by convective storms, and transported thousands of kilometers downwind. Most of the dust is carried west to the Americas and the Caribbean in the Saharan Air Layer (SAL). Dust air masses predominately impact northern South America during the Northern Hemisphere winter and the Caribbean and Southeastern United States in summer. Dust concentrations vary considerably temporally and spatially. In a dust source region (Mali), concentrations range from background levels of 575 micrograms per cubic meter (mu/u g per m3) to 13,000 mu/u g per m3 when visibility degrades to a few meters (Gillies and others, 1996). In the Caribbean, concentrations of 200 to 600 mu/u g per m3 in the mid-Atlantic and Barbados (Prospero and others, 1981; Talbot and others, 1986), 3 to 20 mu/u g per m3 in the Caribbean (Prospero and Nees, 1986; Perry and others, 1997); and >100 mu/u g per m3 in the Virgin Islands (this dataset) have been reported during African dust conditions. Mean dust particle size decreases as the SAL traverses from West Africa to the Caribbean and Americas as a result of gravitational settling. Mean particle size reaching the Caribbean is <1 micrometer (mu/u m) (Perry and others, 1997), and even finer particles are carried into Central America, the Southeastern United States, and maritime Canada. Particles less than 2.5 mu/u m diameter (termed PM2.5) can be inhaled deeply into human lungs. A large body of literature has shown that increased PM2.5 concentrations are linked to increased cardiovascular/respiratory morbidity and mortality (for example, Dockery and others, 1993; Penn and others, 2005).

  19. A principal component regression model to forecast airborne concentration of Cupressaceae pollen in the city of Granada (SE Spain), during 1995-2006.

    PubMed

    Ocaña-Peinado, Francisco M; Valderrama, Mariano J; Bouzas, Paula R

    2013-05-01

    The problem of developing a 2-week-on ahead forecast of atmospheric cypress pollen levels is tackled in this paper by developing a principal component multiple regression model involving several climatic variables. The efficacy of the proposed model is validated by means of an application to real data of Cupressaceae pollen concentration in the city of Granada (southeast of Spain). The model was applied to data from 11 consecutive years (1995-2005), with 2006 being used to validate the forecasts. Based on the work of different authors, factors as temperature, humidity, hours of sun and wind speed were incorporated in the model. This methodology explains approximately 75-80% of the variability in the airborne Cupressaceae pollen concentration.

  20. An investigation on factors influencing dust accumulation on CSP mirrors

    NASA Astrophysics Data System (ADS)

    Pennetta, S.; Yu, S.; Borghesani, P.; Cholette, M.; Barry, John; Guan, Z.

    2016-05-01

    The profitability of a CSP plant is highly affected by the efficiency of the solar field: it is essential to maintain mirrors' reflectivity at high level to avoid thermal power loss. Dust fouling is the main cause of reflectivity loss and cleaning of mirrors is a crucial activity to restore economical level of reflectivity. However, the high cost of cleaning operations requires the study and identification of a balanced plan for the dust removal. The dust generation and transport to the plant site is the first mechanism that needs to be modelled to identify the optimal schedule for cleaning operations and it is highly dependent on weather conditions. Several studies have suggested a dependency of reflectors performance with humidity level, frequency of rainfalls, wind and mirrors' tilting angle, however rarely quantitative correlation studies have been performed to validate these hypotheses. The aim of this research is to provide an in-depth insight on interaction between the main parameters and airborne dust concentration, providing quantitative information for the development of future mirror dusting models. Outcomes evidence the crucial role of high winds responsible of dust concentration in conjunction with higher wind direction frequencies in the range 60-120°. Actually, in this scenario a perfectly monotonic increase of dust accumulation in the air has been observed with high correspondence of wind direction. A very low effect is provided by the ambient temperature as the contribution of the barometric pressure.

  1. Determination of heavy metals concentrations in airborne particulates matter (APM) from Manjung district, Perak using energy dispersive X-ray fluorescence (EDXRF) spectrometer

    NASA Astrophysics Data System (ADS)

    Arshad, Nursyairah; Hamzah, Zaini; Wood, Ab. Khalik; Saat, Ahmad; Alias, Masitah

    2015-04-01

    Airborne particulates trace metals are considered as public health concern as it can enter human lungs through respiratory system. Generally, any substance that has been introduced to the atmosphere that can cause severe effects to living things and the environment is considered air pollution. Manjung, Perak is one of the development districts that is active with industrial activities. There are many industrial activities surrounding Manjung District area such as coal fired power plant, quarries and iron smelting which may contribute to the air pollution into the environment. This study was done to measure the concentrations of Hg, U, Th, K, Cu, Fe, Cr, Zn, As, Se, Pb and Cd in the Airborne Particulate Matter (APM) collected at nine locations in Manjung District area within 15 km radius towards three directions (North, North-East and South-East) in 5 km intervals. The samples were collected using mini volume air sampler with cellulose filter through total suspended particulate (TSP). The sampler was set up for eight hours with the flow rate of 5 L/min. The filter was weighed before and after sample collection using microbalance, to get the amount of APM and kept in desiccator before analyzing. The measurement was done using calibrated Energy Dispersive X-Ray Fluorescence (EDXRF) Spectrometer. The air particulate concentrations were found below the Malaysia Air Quality Guidelines for TSP (260 µg/m3). All of the metals concentrations were also lower than the guidelines set by World Health Organization (WHO), Ontario Ministry of the Environment and Argonne National Laboratory, USA NCRP (1975). From the concentrations, the enrichment factor were calculated.

  2. Dust storms - Great Plains, Africa, and Mars

    NASA Technical Reports Server (NTRS)

    Woiceshyn, P. M.; Krauss, R.; Minzner, R.; Shenk, W.

    1977-01-01

    Dust storms in the Great Plains of North America and in the Sahara Desert are analyzed on the basis of imagery from the geostationary Synchronous Meteorological Satellite. The onset time, location and areal extent of the dust storms are studied. Over land surfaces, contrast enhancement techniques are needed to obtain an adequate picture of dust storm development. In addition, infrared imagery may provide a means of monitoring the strong horizontal temperature gradients characteristic of dust cloud boundaries. Analogies between terrestrial dust storms and the airborne rivers of dust created by major Martian dust storms are also drawn.

  3. Characterizing Dust from Cutting Corian®, a Solid-Surface Composite Material, in a Laboratory Testing System.

    PubMed

    Qi, Chaolong; Echt, Alan; Murata, Taichi K

    2016-06-01

    We conducted a laboratory test to characterize dust from cutting Corian(®), a solid-surface composite material, with a circular saw. Air samples were collected using filters and direct-reading instruments in an automatic laboratory testing system. The average mass concentrations of the total and respirable dusts from the filter samples were 4.78±0.01 and 1.52±0.01mg cm(-3), respectively, suggesting about 31.8% mass of the airborne dust from cutting Corian(®) is respirable. Analysis of the metal elements on the filter samples reveals that aluminum hydroxide is likely the dominant component of the airborne dust from cutting Corian(®), with the total airborne and respirable dusts containing 86.0±6.6 and 82.2±4.1% aluminum hydroxide, respectively. The results from the direct-reading instruments confirm that the airborne dust generated from cutting Corian(®) were mainly from the cutting process with very few particles released from the running circular saw alone. The number-based size distribution of the dusts from cutting Corian(®) had a peak for fine particles at 1.05 µm with an average total concentration of 871.9 particles cm(-3), and another peak for ultrafine particles at 11.8nm with an average total concentration of 1.19×10(6) particles cm(-3) The small size and high concentration of the ultrafine particles suggest additional investigation is needed to study their chemical composition and possible contribution to pulmonary effect.

  4. Symptoms, spirometry, and serum antibody concentrations among compost workers exposed to organic dust.

    PubMed

    van Kampen, Vera; Deckert, Anja; Hoffmeyer, Frank; Taeger, Dirk; Brinkmann, Elmar; Brüning, Thomas; Raulf-Heimsoth, Monika; Bünger, Jürgen

    2012-01-01

    Work-related symptoms and diseases of 190 currently exposed compost workers, 59 former compost workers, and 38 nonexposed control subjects were investigated in a cross-sectional study. Using a standardized questionnaire, participants were asked for work-related symptoms, exposures to bioaerosols, atopic diseases, and smoking habits. The subjects underwent a physical examination and a lung function test. In addition, total immunoglobulin (Ig) E, IgE specific to environmental allergens and moulds, and IgG specific to molds and actinomycetes were quantified. Compared to controls, compost workers suffered more often from cough and irritation of the eyes in terms of mucosal membrane irritation (MMI). Former compost workers reported similar work-related complaints, but most MMI symptoms had improved after termination of bioaerosol exposure. In contrast, cough and dyspnea persisted, indicating a chronic process. Lung function parameters of compost workers were within the reference ranges. Nevertheless, forced vital capacity (FVC) was significantly lower than for controls. Specific IgE to environmental allergens and molds was positive in 25.3% and 7.4%, respectively, of currently exposed compost workers. There were no marked differences in IgE and IgG concentrations among the three groups. Compost workers suffered with a higher frequency from cough and MMI symptoms. The findings that MMI symptoms improved in former compost workers after leaving the job confirmed the association with bioaerosol exposure. Further, the reduced FVC may be produced by this exposure. There was no higher frequency of mold sensitization in the group of compost workers compared to controls, which may be an indication of a healthy worker survivor effect.

  5. A method for computing the damage level due to the exposure to an airborne chemical with a time-varying concentration.

    PubMed

    Acquesta, Alejandro D; Sánchez, Erica Yanina; Porta, Andres; Jacovkis, Pablo M

    2011-09-01

    The calculation of damage level due to the exposure to a toxic cloud is usually not included in most popular software, or it is included using techniques that do not take into account the variation in concentration over a period of time. In this work, a method is introduced for calculating the temporal evolution of the potential damage level and to obtain a more precise and descriptive estimation of this level. The proposed goal is: to estimate the maximum and minimum damage level experienced by a population due to the exposure to an airborne chemical with a time-varying concentration; to be able to assess the damage level experienced in a progressive way, as the exposure to the airborne chemical occurs. The method relies on transformations of time-concentration pairs on a continuum of damage level curves based on the available guideline levels, obtaining maximum and minimum approximations of the expected damage level for any exposure duration. Consequently, applying this method to transport model output data and demographic information, damage evolution in relation to time and space can be predicted, as well as its effect on the local population, which enables the determination of threat zones. The comparison between the proposed method and the current (Spanish and ALOHA) ones showed that the former can offer a more precise estimation and a more descriptive approach of the potential damage level. This method can be used by atmospheric dispersion models to compute damage level and graphically display the regions exposed to each guideline level on area maps.

  6. Airborne polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and dechlorane plus (DP) in concentrated vehicle parking areas.

    PubMed

    Li, Huiru; Liu, Hehuan; Mo, Ligui; Sheng, Guoying; Fu, Jiamo; Peng, Ping'an

    2016-06-01

    This study investigated polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and dechlorane plus (DP) in air around three concentrated vehicle parking areas (underground, indoor, and outdoor) in a metropolitan of South China. The parking areas showed higher concentrations of PBDEs, PBDD/Fs, and DP than their adjacent urban area or distinct congener/isomer profiles, which indicate their local emission sources. The highest PBDE and DP concentrations were found in the outdoor parking lot, which might be related to the heating effect of direct sunlight exposure. Multi-linear regression analysis results suggest that deca-BDEs without noticeable transformation contributed most to airborne PBDEs in all studied areas, followed by penta-BDEs. The statistically lower anti-DP fractions in the urban area than that of commercial product signified its degradation/transformation during transportation. Neither PBDEs nor vehicle exhaust contributed much to airborne PBDD/Fs in the parking areas. There were 68.1-100 % of PBDEs, PBDD/Fs, and DP associated with particles. Logarithms of gas-particle distribution coefficients (K ps) of PBDEs were significantly linear-correlated with those of their sub-cooled vapor pressures (p Ls) and octanol-air partition coefficients (K OAs) in all studied areas. The daily inhalation doses of PBDEs, DP, and PBDD/Fs were individually estimated as 89.7-10,741, 2.05-39.4, and 0.12-4.17 pg kg(-1) day(-1) for employees in the parking areas via Monte Carlo simulation.

  7. Comparison of two direct-reading instruments (FM-7400 and Fibrecheck FC-2) with phase contrast optical microscopy to measure the airborne fibre number concentration.

    PubMed

    Kauffer, E; Martin, P; Grzebyk, M; Villa, M; Vigneron, J C

    2003-07-01

    The use of direct-reading instruments to measure the airborne fibre number concentration is on the increase. The response of two of these instruments (FM-7400 and Fibrecheck FC-2) was compared with the conventional method of sampling on filters and counting by phase contrast microscopy. Four types of fibres were studied at different concentrations and relative humidity levels. The FM-7400 can be calibrated by the manufacturer for two different levels of sensitivity (standard and high). For the tests where it was set to the sensitivity level with which it had been calibrated, the ratio of the concentration measured by the instrument to the concentration obtained by the conventional method varied in the range 0.5-1 for the different types of fibres studied (chrysotile, glass wool and ceramic fibres). The Fibrecheck FC-2 is a much less versatile instrument. On the basis of a calibration allowing correct detection of asbestos fibres, it greatly overestimated the concentration of man-made mineral fibres. In its normal calibration state a fine chrysotile aerosol was poorly detected. For man-made mineral fibres, the response was highly dependent on the nature of the fibres. These instruments require calibration with the type of fibres to be studied. Unfortunately, this operation is not always accessible to the user and may require the services of a specialized laboratory, as the manufacturer is not always in a position to carry this out.

  8. Pulmonary toxicity of dust generated during weaving of carpets.

    PubMed

    Ameen, M; Ahmad, I; Rahman, Q

    2002-12-01

    The dust generated during weaving (carpet dust) tibbati, knotted and tuffted carpets in carpet industry was studied for its toxicity in vitro and in vivo. Carpet dust (0.5, 1.0, 2.5 and 5.0 mg/1 x 10(6) cells) caused in vitro cytotoxicity in rat alveolar macrophages (AM) in a concentration-dependent manner. The cytotoxic, inflammatory and oxidative responses were observed in bronchoalveolar lavage fluid (BALF) of rats at 1, 4, 8 and 16 days after exposure. Rats were intratracheally exposed at 5 mg/rat individually to all three types of carpet dust. All types of carpet dusts produced increased AM, lymphocytes (PMN) population in BALF suggesting their inflammatory reactions. Cytotoxic nature of carpet dust was shown by the increased activities of lactate dehydrogenase (LDH) and acid phosphatase (AP) in BALF. Increased AM population and in vitro cytotoxicity due to carpet dusts have shown some correlation with the levels of LDH and AP activities in BALF. The gradual enhanced profile of hydrogen peroxide (H2O2) and nitric oxide (NO) along with depletion of reduced glutathione (GSH) in AM due to these carpet dusts are suggestive of their oxidant nature. The enzyme activities of both glutathione peroxidase (GPx) and glutathione reductase (GR) in AM were marginally reduced in exposed rats. In conclusion, the data suggest the cytotoxic, inflammatory and oxidant nature of carpet dusts. It is extrapolated that health effects on carpet weavers would be associated with the concentration and nature of airborne dust generated during weaving of carpets.

  9. Exposure to wood dust and heavy metals in workers using CCA pressure-treated wood.

    PubMed

    Decker, Paul; Cohen, Beverly; Butala, John H; Gordon, Terry

    2002-01-01

    Chemical pesticide treatment enables relatively nonresistant woods to be used in outdoor construction projects. The most prevalent procedure used to protect these woods is pressure treatment with chromium, copper, and arsenic (CCA). This pilot study examined the airborne concentration and particle size distribution of wood particles, chromium, copper, and arsenic at both outdoor (measured over the whole work day) and indoor (measured during the performance of specific tasks) work sites. At the outdoor residential deck construction sites, the arithmetic mean total dust concentration, measured using personal filter cassette samplers, was 0.57 mg/m3. The mass median aerodynamic diameter (da) of the outdoor wood dust was greater than 20 microm. Indoor wood dust concentrations were significantly greater than those measured outdoor and were job category-dependent. The highest mean breathing zone dust concentration, 49.0 mg/m3, was measured at the indoor sanding operation. Personal impactor sampling demonstrated that the mean total airborne concentration of arsenic, but not chromium or copper, was consistently above recommended occupational exposure levels at the indoor work site, and occasionally at the outdoor work sites. At the indoor sanding operation, the mean total chromium, copper, and arsenic concentrations were 345, 170, and 342 microg/m3, respectively. Thus, significant exposure to airborne heavy metals can occur as a result of indoor and outdoor exposure to CCA pressure-treated wood dust. Therefore, current standards for wood dust may not adequately protect workers from the heavy metals commonly used in CCA pressure-treated wood.

  10. Assessment and determinants of airborne bacterial and fungal concentrations in different indoor environments: Homes, child day-care centres, primary schools and elderly care centres

    NASA Astrophysics Data System (ADS)

    Madureira, Joana; Paciência, Inês; Rufo, João Cavaleiro; Pereira, Cristiana; Teixeira, João Paulo; de Oliveira Fernandes, Eduardo

    2015-05-01

    Until now the influence of risk factors resulting from exposure to biological agents in indoor air has been far less studied than outdoor pollution; therefore the uncertainty of health risks, and how to effectively prevent these, remains. This study aimed (i) to quantify airborne cultivable bacterial and fungal concentrations in four different types of indoor environment as well as to identify the recovered fungi; (ii) to assess the impact of outdoor bacterial and fungal concentrations on indoor air; (iii) to investigate the influence of carbon dioxide (CO2), temperature and relative humidity on bacterial and fungal concentrations; and (iv) to estimate bacterial and fungal dose rate for children (3-5 years old and 8-10 years old) in comparison with the elderly. Air samples were collected in 68 homes, 9 child day-care centres, 20 primary schools and 22 elderly care centres, in a total of 264 rooms with a microbiological air sampler and using tryptic soy agar and malt extract agar culture media for bacteria and fungi growth, respectively. For each building, one outdoor representative location were identified and simultaneously studied. The results showed that child day-care centres were the indoor microenvironment with the highest median bacterial and fungal concentrations (3870 CFU/m3 and 415 CFU/m3, respectively), whereas the lowest median concentrations were observed in elderly care centres (222 CFU/m3 and 180 CFU/m3, respectively). Indoor bacterial concentrations were significantly higher than outdoor concentrations (p < 0.05); whereas the indoor/outdoor ratios for the obtained fungal concentrations were approximately around the unit. Indoor CO2 levels were associated with the bacterial concentration, probably due to occupancy and insufficient ventilation. Penicillium and Cladosporium were the most frequently occurring fungi. Children's had two times higher dose rate to biological pollutants when compared to adult individuals. Thus, due to children

  11. Trace-metal concentrations in African dust: effects of long-distance transport and implications for human health

    USGS Publications Warehouse

    Garrison, Virginia; Lamothe, Paul; Morman, Suzette; Plumlee, Geoffrey S.; Gilkes, Robert; Prakongkep, Nattaporn

    2010-01-01

    The Sahara and Sahel lose billions of tons of eroded mineral soils annually to the Americas and Caribbean, Europe and Asia via atmospheric transport. African dust was collected from a dust source region (Mali, West Africa) and from downwind sites in the Caribbean [Trinidad-Tobago (TT) and U.S. Virgin Islands (VI)] and analysed for 32 trace-elements. Elemental composition of African dust samples was similar to that of average upper continental crust (UCC), with some enrichment or depletion of specific trace-elements. Pb enrichment was observed only in dust and dry deposition samples from the source region and was most likely from local use of leaded gasoline. Dust particles transported long-distances (VI and TT) exhibited increased enrichment of Mo and minor depletion of other elements relative to source region samples. This suggests that processes occurring during long-distance transport of dust produce enrichment/depletion of specific elements. Bioaccessibility of trace-metals in samples was tested in simulated human fluids (gastric and lung) and was found to be greater in downwind than source region samples, for some metals (e.g., As). The large surface to volume ratio of the dust particles (<2.5 µm) at downwind sites may be a factor.

  12. Application phenomena and efficacy of concentrated acaricide dusts for northern fowl mite control on caged laying hens.

    PubMed

    Hall, R D; Foehse, M C; Vandepopuliere, J M

    1981-06-01

    Fluorescent pigments were used to measure plumage coverage when caged laying hens were dusted for northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), control. Carriage type electrostatic or high velocity backpack equipment produced superior coverage 2 hr posttreatment when the rates of 454 g (1 lb) dust per 100 or 500 hens was employed. A redistribution of dust was noted 48 hr posttreatment, and a subsequent experiment demonstrated that this phenomenon resulted from intracage cross contamination dependent upon bird caging density. Carbaryl 80% wettable powder (WP) at 454 g/1600 hens and tetrachlorvinphos 50% WP at 454 g/1000 hens provided northern fowl mite control for 11 and 5 weeks posttreatment, respectively.

  13. Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites.

    PubMed

    Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

    2015-08-12

    Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R(2)) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning.

  14. Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites

    PubMed Central

    Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

    2015-01-01

    Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R2) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning. PMID:26274959

  15. Concentrations of polybrominated diphenyl ethers (PBDEs) in central air-conditioner filter dust and relevance of non-dietary exposure in occupational indoor environments in Greece.

    PubMed

    Besis, Athanasios; Katsoyiannis, Athanasios; Botsaropoulou, Elisavet; Samara, Constantini

    2014-05-01

    Polybrominated Diphenyl Ethers (PBDEs) are ubiquitous in the indoor environment owing to their use in consumer products and various studies around the world have found higher concentrations indoors than outdoors. Central air conditioner (A/C) systems have been widely used in many workplaces, therefore, studying of PBDEs in central A/C filter dust is useful to better understand the occurrences and health implications of PBDEs in indoor environments. The present study examined the occurrence of PBDEs in central A/C filter dust collected from various workplaces (n = 20) in Thessaloniki, Greece. The sum concentrations of 21 target congeners (∑21PBDE) in A/C dust ranged between 84 and 4062 ng g(-1) with a median value of 1092 ng g(-1), while BDE-209 was found to be the most abundant BDE congener. The daily intake via dust ingestion of PBDEs estimated for the employees of the occupational settings ranged from 3 to 45 ng day(-1) (median 12 ng day(-1)).

  16. Dust, Climate, and Human Health

    NASA Technical Reports Server (NTRS)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. Ths paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  17. Dust, Climate, and Human Health

    NASA Technical Reports Server (NTRS)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  18. Comparison of direct (X-ray diffraction and infrared spectrophotometry) and indirect (infrared spectrophotometry) methods for the analysis of alpha-quartz in airborne dusts.

    PubMed

    Kauffer, E; Masson, A; Moulut, J C; Lecaque, T; Protois, J C

    2005-11-01

    In this study, the alpha-quartz contents measured by different analytical techniques (X-ray diffraction, direct method; and infrared spectrophotometry, direct and indirect methods) were compared. The analyses were carried out on filters sampled in an industrial setting by means of a Dorr-Oliver cyclone. To verify the methodology used, filters loaded with pure alpha-quartz were also analysed. By and large, the agreement between the two direct methods was close on average, but on the basis of a comparison of the individual results, considerable differences exist. In absolute value, the mean relative deviation between the two techniques was <25% in only 47.8% of the cases. The results obtained by the indirect method (infrared) were on average 13% lower than the results obtained by the two direct methods with a more important difference (23%) for samples where calcite was identified by X-ray diffraction in comparison with those where it was not (8%). This underestimation, which was not owing to dust losses during preparation, is probably explained by the elimination of organic compounds during dust calcinations or by the transformation of mineral compounds. The indirect method introduces additional sample handling operations with more risk of material loss. When the quantity of calcined material was <0.4 mg, the weighing operations necessary to correct any losses of material resulted in considerable variability. In terms of overall uncertainty, it would be better in this case not to carry out correction and to employ an operating mode favouring the recovery of a maximum of material while accepting a bias of about 5-7%.

  19. Muramic acid, endotoxin, 3-hydroxy fatty acids, and ergosterol content explain monocyte and epithelial cell inflammatory responses to agricultural dusts.

    PubMed

    Poole, Jill A; Dooley, Gregory P; Saito, Rena; Burrell, Angela M; Bailey, Kristina L; Romberger, Debra J; Mehaffy, John; Reynolds, Stephen J

    2010-01-01

    In agricultural and other environments, inhalation of airborne microorganisms is linked to respiratory disease development. Bacterial endotoxins, peptidoglycans, and fungi are potential causative agents, but relative microbial characterization and inflammatory comparisons amongst agricultural dusts are not well described. The aim of this study was to determine the distribution of microbial endotoxin, 3-hydroxy fatty acids (3-OHFA), muramic acid, and ergosterol and evaluate inflammatory responses in human monocytes and bronchial epithelial cells with various dust samples. Settled surface dust was obtained from five environments: swine facility, dairy barn, grain elevator, domestic home (no pets), and domestic home with dog. Endotoxin concentration was determined by recombinant factor C (rFC). 3-OHFA, muramic acid, and ergosterol were measured using gas chromatography-mass spectrometry. Dust-induced inflammatory cytokine secretion in human monocytes and bronchial epithelial cells was evaluated. Endotoxin-independent dust-induced inflammatory responses were evaluated. Endotoxin and 3-OHFA levels were highest in agricultural dusts. Muramic acid, endotoxin, 3-OHFA, and ergosterol were detected in dusts samples. Muramic acid was highest in animal farming dusts. Ergosterol was most significant in grain elevator dust. Agricultural dusts induced monocyte tumor necrosis factor (TNF) alpha, interleukin (IL)-6, IL-8, and epithelial cell IL-6 and IL-8 secretion. Monocyte and epithelial IL-6 and IL-8 secretion was not dependent on endotoxin. House dust(s) induced monocyte TNFalpha, IL-6, and IL-8 secretion. Swine facility dust generally produced elevated responses compared to other dusts. Agricultural dusts are complex with significant microbial component contribution. Large animal farming dust(s)-induced inflammation is not entirely dependent on endotoxin. Addition of muramic acid to endotoxin in large animal farming environment monitoring is warranted.

  20. Treated and untreated rock dust: Quartz content and physical characterization.

    PubMed

    Soo, Jhy-Charm; Lee, Taekhee; Chisholm, William P; Farcas, Daniel; Schwegler-Berry, Diane; Harper, Martin

    2016-11-01

    Rock dusting is used to prevent secondary explosions in coal mines, but inhalation of rock dusts can be hazardous if the crystalline silica (e.g., quartz) content in the respirable fraction is high. The objective of this study is to assess the quartz content and physical characteristics of four selected rock dusts, consisting of limestone or marble in both treated (such as treatment with stearic acid or stearates) and untreated forms. Four selected rock dusts (an untreated and treated limestone and an untreated and treated marble) were aerosolized in an aerosol chamber. Respirable size-selective sampling was conducted along with particle size-segregated sampling using a Micro-Orifice Uniform Deposit Impactor. Fourier Transform Infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analyses were used to determine quartz mass and particle morphology, respectively. Quartz percentage in the respirable dust fraction of untreated and treated forms of the limestone dust was significantly higher than in bulk samples, but since the bulk percentage was low the enrichment factor would not have resulted in any major change to conclusions regarding the contribution of respirable rock dust to the overall airborne quartz concentration. The quartz percentage in the marble dust (untreated and treated) was very low and the respirable fractions showed no enrichment. The spectra from SEM-EDX analysis for all materials were predominantly from calcium carbonate, clay, and gypsum particles. No free quartz particles were observed. The four rock dusts used in this study are representative of those presented for use in rock dusting, but the conclusions may not be applicable to all available materials.

  1. Treated and Untreated Rock Dust: Quartz Content and Physical Characterization

    PubMed Central

    Soo, Jhy-Charm; Lee, Taekhee; Chisholm, William P.; Farcas, Daniel; Schwegler-Berry, Diane; Harper, Martin

    2016-01-01

    SUMMARY Rock dusting is used to prevent secondary explosions in coal mines, but inhalation of rock dusts can be hazardous if the crystalline silica (e.g., quartz) content in the respirable fraction is high. The objective of this study is to assess the quartz content and physical characteristics of four selected rock dusts, consisting of limestone or marble in both treated (such as treatment with stearic acid or stearates) and untreated forms. Four selected rock dusts (an untreated and treated limestone and an untreated and treated marble) were aerosolized in an aerosol chamber. Respirable size-selective sampling was conducted along with particle size-segregated sampling using a Micro-Orifice Uniform Deposit Impactor. Fourier Transform Infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) analyses were used to determine quartz mass and particle morphology, respectively. Quartz percentage in the respirable dust fraction of untreated and treated forms of the limestone dust was significantly higher than in bulk samples, but since the bulk percentage was low the enrichment factor would not have resulted in any major change to conclusions regarding the contribution of respirable rock dust to the overall airborne quartz concentration. The quartz percentage in the marble dust (untreated and treated) was very low and the respirable fractions showed no enrichment. The spectra from SEM-EDX analysis for all materials were predominantly from calcium carbonate, clay, and gypsum particles. No free quartz particles were observed. The four rock dusts used in this study are representative of those presented for use in rock dusting, but the conclusions may not be applicable to all available materials. PMID:27314444

  2. Airborne Measurements of Aerosol Size Distributions During PACDEX

    NASA Astrophysics Data System (ADS)

    Rogers, D. C.; Gandrud, B.; Campos, T.; Kok, G.; Stith, J.

    2007-12-01

    The Pacific Dust Experiment (PACDEX) is an airborne project that attempts to characterize the indirect aerosol effect by tracing plumes of dust and pollution across the Pacific Ocean. This project occurred during April-May 2007 and used the NSF/NCAR HIAPER research aircraft. When a period of strong generation of dust particles and pollution was detected by ground-based and satellite sensors, then the aircraft was launched from Colorado to Alaska, Hawaii, and Japan. Its mission was to intercept and track these plumes from Asia, across the Pacific Ocean, and ultimately to the edges of North America. For more description, see the abstract by Stith and Ramanathan (this conference) and other companion papers on PACDEX. The HIAPER aircraft carried a wide variety of sensors for measuring aerosols, cloud particles, trace gases, and radiation. Sampling was made in several weather regimes, including clean "background" air, dust and pollution plumes, and regions with cloud systems. Altitude ranges extended from 100 m above the ocean to 13.4 km. This paper reports on aerosol measurements made with a new Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), a Radial Differential Mobility Analyzer (RDMA), a water-based CN counter, and a Cloud Droplet Probe (CDP). These cover the size range 10 nm to 10 um diameter. In clear air, dust was detected with the UHSAS and CDP. Polluted air was identified with high concentrations of carbon monoxide, ozone, and CN. Aerosol size distributions will be presented, along with data to define the context of weather regimes.

  3. The Martian Dust Cycle: Observations and Modeling

    NASA Technical Reports Server (NTRS)

    Kahre, Melinda A.

    2013-01-01

    The dust cycle is critically important for Mars' current climate system. Suspended atmospheric dust affects the radiative balance of the atmosphere, and thus greatly influences the thermal and dynamical state of the atmosphere. Evidence for the presence of dust in the Martian atmosphere can be traced back to yellow clouds telescopically observed as early as the early 19th century. The Mariner 9 orbiter arrived at Mars in November of 1971 to find a planet completely enshrouded in airborne dust. Since that time, the exchange of dust between the planet's surface and atmosphere and the role of airborne dust on Mars' weather and climate has been studied using observations and numerical models. The goal of this talk is to give an overview of the observations and to discuss the successes and challenges associated with modeling the dust cycle. Dust raising events on Mars range in size from meters to hundreds of kilometers. During some years, regional storms merge to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by tens of kelvin. The interannual variability of planet encircling dust storms is poorly understood. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. A low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading are generally observed: one peak occurs before northern winter solstice and one peak occurs after northern winter solstice. Numerical modeling studies attempting to interactively simulate the Martian dust cycle with general circulation models (GCMs) include the lifting, transport, and sedimentation of radiatively active dust. Two dust lifting processes are commonly represented in

  4. Relationships between airborne fungal spore concentration of Cladosporium and the summer climate at two sites in Britain

    NASA Astrophysics Data System (ADS)

    Hollins, P. D.; Kettlewell, P. S.; Atkinson, M. D.; Stephenson, D. B.; Corden, J. M.; Millington, W. M.; Mullins, J.

    Cladosporium conidia have been shown to be important aeroallergens in many regions throughout the world, but annual spore concentrations vary considerably between years. Understanding these annual fluctuations may be of value in the clinical management of allergies. This study investigates the number of days in summer when spore concentration exceeds the allergenic threshold in relation to regional temperature and precipitation at two sites in England and Wales over 27 years. Results indicate that number of days in summer when the Cladosporium spores are above the allergenic concentration is positively correlated with regional temperature and negatively correlated with precipitation for both sites over the study period. Further analysis used a winter North Atlantic Oscillation index to explore the potential for long-range forecasting of the aeroallergen. For both spore measurement sites, a positive correlation exists between the winter North Atlantic Oscillation index and the number of days in summer above the allergenic threshold for Cladosporium spore concentration.

  5. Spatial and temporal variabilities of spring Asian dust events and their impacts on chlorophyll-a concentrations in the western North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Yoon, Joo-Eun; Kim, Kitae; Macdonald, Alison M.; Park, Ki-Tae; Kim, Hyun-Cheol; Yoo, Kyu-Cheul; Yoon, Ho-Il; Yang, Eun Jin; Jung, Jinyoung; Lim, Jae-Hyun; Kim, Ju-Hyoung; Lee, Jiyoung; Choi, Tae-Jun; Song, Jae-Min; Kim, Il-Nam

    2017-02-01

    As the western North Pacific Ocean is located downwind of the source regions for spring Asian dust, it is an ideal location for determining the response of open waters to these events. Spatial analysis of spring Asian dust events from source regions to the western North Pacific, using long-term daily aerosol index data, revealed three different transport pathways supported by the westerly wind system: one passing across the northern East/Japan Sea (40°N-50°N), a second moving over the entire East/Japan Sea (35°N-55°N), and a third flowing predominantly over the Siberian continent (>50°N). Our results indicate that strong spring Asian dust events can increase ocean primary productivity by more than 70% (>2-fold increase in chlorophyll-a concentrations) compared to weak/nondust conditions. Therefore, attention should be paid to the recent downturn in the number of spring Asian dust events and to the response of primary production in the western North Pacific to this change.

  6. Source Identification Of Airborne Antimony On The Basis Of The Field Monitoring And The Source Profiling

    NASA Astrophysics Data System (ADS)

    Iijima, A.; Sato, K.; Fujitani, Y.; Fujimori, E.; Tanabe, K.; Ohara, T.; Shimoda, M.; Kozawa, K.; Furuta, N.

    2008-12-01

    The results of the long-term monitoring of airborne particulate matter (APM) in Tokyo indicated that APM have been extremely enriched with antimony (Sb) compared to crustal composition. This observation suggests that the airborne Sb is distinctly derived from human activities. According to the material flow analysis, automotive brake abrasion dust and fly ash from waste incinerator were suspected as the significant Sb sources. To clarify the emission sources of the airborne Sb, elemental composition, particle size distribution, and morphological profiles of dust particles collected from two possible emission sources were characterized and compared to the field observation data. Brake abrasion dust samples were generated by using a brake dynamometer. During the abrasion test, particle size distribution was measured by an aerodynamic particle sizer spectrometer. Concurrently, size- classified dust particles were collected by an Andersen type air sampler. Fly ash samples were collected from several municipal waste incinerators, and the bulk ash samples were re-dispersed into an enclosed chamber. The measurement of particle size distribution and the collection of size-classified ash particles were conducted by the same methodologies as described previously. Field observations of APM were performed at a roadside site and a residential site by using an Andersen type air sampler. Chemical analyses of metallic elements were performed by an inductively coupled plasma atomic emission spectrometry and an inductively coupled plasma mass spectrometr. Morphological profiling of the individual particle was conducted by a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. High concentration of Sb was detected from both of two possible sources. Particularly, Sb concentrations in a brake abrasion dust were extremely high compared to that in an ambient APM, suggesting that airborne Sb observed at the roadside might have been largely derived from

  7. 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.

  8. Influence of regional biomass burning on the highly elevated organic carbon concentrations observed at Gosan, South Korea during a strong Asian dust period.

    PubMed

    Nguyen, Duc Luong; Kim, Jin Young; Ghim, Young Sung; Shim, Shang-Gyoo

    2015-03-01

    PM2.5 carbonaceous particles were measured at Gosan, South Korea during 29 March-11 April 2002 which includes a pollution period (30 March-01 April) when the highest concentrations of major anthropogenic species (nss-SO4 (2-), NO3 (-), and NH4 (+)) were observed and a strong Asian dust (AD) period (08-10 April) when the highest concentrations of mainly dust-originated trace elements (Al, Ca, Mg, and Fe) were seen. The concentrations of elemental carbon (EC) measured in the pollution period were higher than those measured in the strong AD period, whereas an inverse variation in the concentrations of organic carbon (OC) was observed. Based on the OC/EC ratios, the possible source that mainly contributed to the highly elevated OC concentrations measured in the strong AD period was biomass burning. The influence of the long-range transport of smoke plumes emitted from regional biomass burning sources was evaluated by using MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data for fire locations and the potential source contribution function analysis. The most potential source regions of biomass burning were the Primorsky and Amur regions in Far Eastern Russia and southeastern and southwestern Siberia, Russia. Further discussion on the source characteristics suggested that the high OC concentrations measured in the strong AD period were significantly affected by the smoldering phase of biomass burning. In addition to biomass burning, secondary OC (SOC) formed during atmospheric long-range transport should be also considered as an important source of OC concentration measured at Gosan. Although this study dealt with the episodic case of the concurrent increase of dust and biomass burning particles, understanding the characteristics of heterogeneous mixing aerosol is essential in assessing the radiative forcing of aerosol.

  9. The application of a multi-wavelength Aethalometer to estimate iron dust and black carbon concentrations in the marine boundary layer of Cape Verde

    NASA Astrophysics Data System (ADS)

    Fialho, P.; Cerqueira, M.; Pio, C.; Cardoso, J.; Nunes, T.; Custódio, D.; Alves, C.; Almeida, S. M.; Almeida-Silva, M.; Reis, M.; Rocha, F.

    2014-11-01

    The two-component model (Fialho et al., 2006) was used to decouple the contributions of black carbon (BC) and iron oxides, present in dust, to the aerosol attenuation coefficient, measured with a multi-wavelength Aethalometer. The model results were compared with the elemental carbon (EC) and iron concentrations determined in the laboratory from the analysis of aerosol particles collected with conventional samplers. The comparison was based on one year of data obtained at Praia, Santiago Island, Cape Verde, after side by side operation of the aerosol monitoring instruments. The linear regression equation that best describes the relationship between BC concentrations, derived from the Aethalometer, and EC concentrations, derived from a PM10 high-volume sampler after filter analysis with a thermal optical method, presents a slope of 1.01 ± 0.05 and a correlation coefficient (r) of 0.90, showing that the model worked as intended to describe BC concentrations without interferences from iron dust. On the other hand, the linear regression equation that best describes the relationship between the iron concentrations derived from the Aethalometer and elemental iron concentrations, derived from a PM10 low-volume sampler after filter analysis by k0 - Instrumental Neutron Activation Analysis, presents a slope of 0.495 ± 0.014 and a correlation coefficient (r) of 0.96. These results show that the two-component model underestimated the iron concentrations in dust aerosol, which was explained by differences in the size range of particles sampled with the Aethalometer and the PM10 low-volume sampler together with differences in the size distribution of iron oxides.

  10. The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level.

    PubMed

    Oliveira, M; Ribeiro, H; Delgado, J L; Abreu, I

    2009-01-01

    Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005-2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores (Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores (Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.

  11. Vinyl flooring in the home is associated with children’s airborne butylbenzyl phthalate and urinary metabolite concentrations

    PubMed Central

    Just, Allan C.; Miller, Rachel L.; Perzanowski, Matthew S.; Rundle, Andrew G.; Chen, Qixuan; Jung, Kyung Hwa; Hoepner, Lori; Camann, David E.; Calafat, Antonia M.; Perera, Frederica P.; Whyatt, Robin M.

    2015-01-01

    Prior studies have shown that vinyl flooring, as well as the vinyl-softening plasticizers butylbenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP), are associated with asthma and airway inflammation. While DEHP exposure is primarily dietary, whether home vinyl flooring contributes to indoor air and urinary metabolite concentrations for these two phthalates is unclear. Exposures to BBzP and DEHP were examined in a prospective birth cohort of New York City children (n=239) using: (1) visual observation of potential phthalate containing flooring, (2) a two-week home indoor air sample, and (3) concurrent urinary metabolites in a subset (n=193). The category “vinyl or linoleum” flooring was observed in 135 (56%) of monitored rooms; these rooms had statistically significantly higher indoor air geometric mean concentrations of BBzP (23.9 ng/m3) than rooms with wood or carpet flooring (10.6 ng/m3). Children from homes with “vinyl or linoleum” flooring also had significantly higher urinary BBzP metabolite concentrations than other children. Indoor air BBzP and urinary metabolite concentrations were correlated positively (Spearman’s rho 0.40). By contrast, indoor air DEHP was not associated with flooring type nor with its urinary metabolite concentrations. Vinyl flooring in the home may be an important source of children’s exposure to BBzP via indoor air. PMID:25690585

  12. The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level

    NASA Astrophysics Data System (ADS)

    Oliveira, M.; Ribeiro, H.; Delgado, J. L.; Abreu, I.

    2009-01-01

    Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005-2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores ( Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores ( Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.

  13. Day-time and night-time concentrations of airborne iron particles in the atmosphere of Madrid.

    PubMed

    Valero, F; Mura, M C

    1991-01-01

    Specific measurements of iron aerosol have been made over a 70 days period at a semi-urban site of Madrid. Measurements were made with the idea of assessing the relative contributions of day-time and night-time concentrations to daily ones. Statistics of day-time, night-time, daily and survey time period concentrations are given. Time variations were studied as well, clearly showing daily cyclical pattern identified by applying time spectral analysis. This periodicity is undoubtedly due to level differences between day-time and night-time concentrations of aerosol. Day-time average level ranged from 0.23 to 5.13 micrograms/m3 over the entire survey period (70 days) in contrast with night-times ones ranging from 0.17 to 3.04 micrograms/m3. Night-time/day-time concentration ratio shows a highly consistent value, 0.430 + 0.25 (sigma) during this period. On occasion when diffusion conditions are similar, this ratio increases to 0.518 + 0.18 (sigma). Day-time, night-time and daily concentrations correlation matrix suggests that former is the best daily level indicator.

  14. Airborne concentrations of PM(2.5) and diesel exhaust particles on Harlem sidewalks: a community-based pilot study.

    PubMed

    Kinney, P L; Aggarwal, M; Northridge, M E; Janssen, N A; Shepard, P

    2000-03-01

    Residents of the dense urban core neighborhoods of New York City (NYC) have expressed increasing concern about the potential human health impacts of diesel vehicle emissions. We measured concentrations of particulate matter [less than/equal to] 2.5 micro in aerodynamic diameter (PM(2.5)) and diesel exhaust particles (DEP) on sidewalks in Harlem, NYC, and tested whether spatial variations in concentrations were related to local diesel traffic density. Eight-hour (1000-1800 hr) air samples for PM(2.5 )and elemental carbon (EC) were collected for 5 days in July 1996 on sidewalks adjacent to four geographically distinct Harlem intersections. Samples were taken using portable monitors worn by study staff. Simultaneous traffic counts for diesel trucks, buses, cars, and pedestrians were carried out at each intersection on [Greater/equal to] 2 of the 5 sampling days. Eight-hour diesel vehicle counts ranged from 61 to 2,467 across the four sites. Mean concentrations of PM(2.5) exhibited only modest site-to-site variation (37-47 microg/m(3)), reflecting the importance of broader regional sources of PM(2.5). In contrast, EC concentrations varied 4-fold across sites (from 1.5 to 6 microg/m(3)), and were associated with bus and truck counts on adjacent streets and, at one site, with the presence of a bus depot. A high correlation (r = 0.95) was observed between EC concentrations measured analytically and a blackness measurement based on PM(2.5) filter reflectance, suggesting the utility of the latter as a surrogate measure of DEP in future community-based studies. These results show that local diesel sources in Harlem create spatial variations in sidewalk concentrations of DEP. The study also demonstrates the feasibility of a new paradigm for community-based research involving full and active partnership between academic scientists and community-based organizations.

  15. Implementation of a near-real time cross-border web-mapping platform on airborne particulate matter (PM) concentration with open-source software

    NASA Astrophysics Data System (ADS)

    Knörchen, Achim; Ketzler, Gunnar; Schneider, Christoph

    2015-01-01

    Although Europe has been growing together for the past decades, cross-border information platforms on environmental issues are still scarce. With regard to the establishment of a web-mapping tool on airborne particulate matter (PM) concentration for the Euregio Meuse-Rhine located in the border region of Belgium, Germany and the Netherlands, this article describes the research on methodical and technical backgrounds implementing such a platform. An open-source solution was selected for presenting the data in a Web GIS (OpenLayers/GeoExt; both JavaScript-based), applying other free tools for data handling (Python), data management (PostgreSQL), geo-statistical modelling (Octave), geoprocessing (GRASS GIS/GDAL) and web mapping (MapServer). The multilingual, made-to-order online platform provides access to near-real time data on PM concentration as well as additional background information. In an open data section, commented configuration files for the Web GIS client are being made available for download. Furthermore, all geodata generated by the project is being published under public domain and can be retrieved in various formats or integrated into Desktop GIS as Web Map Services (WMS).

  16. Retrieval of Vertical Structure of Atmospheric CO2 Concentration from Airborne Lidar Measurements during the 2011 and 2013 ASCENDS Science Campaigns

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ramanathan, A.; Rodriguez, M.; Allan, G. R.; Hasselbrack, W.; Abshire, J. B.; Riris, H.; Kawa, S. R.; Weaver, C. J.; Browell, E. V.

    2013-12-01

    NASA Goddard is developing an integrated-path, differential absorption (IPDA) lidar approach to measure atmospheric CO2 concentrations from space as a candidate for NASA's ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission. The approach uses pulsed lasers to measure both CO2 and O2 absorption simultaneously in the vertical path to the surface at a number of wavelengths across a CO2 line at 1572.335 nm and the O2 line doublet near 764.7 nm. Measurements of time-resolved laser backscatter profiles from the atmosphere allow the technique to estimate column CO2 and O2 number density and range to cloud tops in addition to those to the ground. This allows sampling the vertical structure of CO2 and O2 when broken and/or thin clouds are present. This additional information can improve absorption line fits and estimates of column-averaged CO2 and O2 number density, and help isolate and identify sources/sinks of CO2 near the surface. We show some preliminary results of this capability using airborne lidar measurements from the summer 2011 and winter 2013 ASCENDS campaigns. These show simultaneous retrievals of CO2 and O2 column densities for laser returns from ground, low-altitude clouds and cirrus clouds. CO2 concentration in the planetary boundary layer, free troposphere, and lower stratosphere are estimated and compared to those from in-situ CO2 profiles measured during the campaigns.

  17. Conveyor dust control

    SciTech Connect

    Goldbeck, L.

    1999-11-01

    In the past, three different approaches have been used to control dust arising at conveyor load zones. They are: Dust Containment consists of those mechanical systems employed to keep material inside the transfer point with the main material body. Dust Suppression systems increase the mass of suspended dust particles, allowing them to fall from the air stream. Dust Collection is the mechanical capture and return of airborne material after it becomes airborne from the main material body. Previously, these three approaches have always been seen as separate entities. They were offered by separate organizations competing in the marketplace. The three technologies vied for their individual piece of the rock, at the expense of the other technologies (and often at the expense of overall success). There have been considerable amounts of I`m better selling, as well as finger pointing at the other systems when problems arose. Each system claimed its own technology was the best, providing the most effective, most cost-efficient, most maintenance-free solution to fugitive material.

  18. Comparison of industrial emissions and carpet dust concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in a multi-center U.S. study.

    PubMed

    Deziel, Nicole C; Nuckols, John R; Jones, Rena R; Graubard, Barry I; De Roos, Anneclaire J; Pronk, Anjoeka; Gourley, Chris; Colt, Joanne S; Ward, Mary H

    2017-02-15

    Proximity to facilities emitting polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) has been associated with increased risk of non-Hodgkin lymphoma (NHL). There is limited information about whether proximity to industrial sources leads to indoor PCDD/F contamination of homes. We measured carpet dust concentrations (pg/g) of 17 toxic PCDD/F congeners and calculated their toxic equivalence (TEQ) in 100 homes in a population-based case-control study of NHL in Detroit, Los Angeles, Seattle, and Iowa (1998-2000). We took global positioning system readings at residences and obtained coordinates and PCDD/F emissions (ng TEQ/yr) from an Environmental Protection Agency database for 6 facility types: coal-fired electricity generating plants, cement kilns burning non-hazardous waste, hazardous waste incinerators, medical waste incinerators, municipal solid waste incinerators, and sewage sludge incinerators. For each residence, we computed an inverse distance-squared weighted average emission index (AEI [pg TEQ/km(2)/yr]) for all facilities within 5km from 1983 to 2000. We also computed AEIs for each of the 6 facility types. We evaluated relationships between PCDD/F dust concentrations and the all-facility AEI or categories of facility-type AEIs using multivariable linear regression, adjusting for study center, demographics, and home characteristics. A doubling of the all-facility AEI was associated with a 4-8% increase in PCDD/F dust concentrations of 7 of 17 PCDD/F congeners and the TEQ (p-value<0.1). We also observed positive associations between PCDD/F dust concentrations and facility-type AEIs (highest vs. lowest exposure category) for municipal solid waste incinerators (9 PCDD/F, TEQ), and medical waste incinerators (7 PCDD/F, TEQ) (p<0.1). Our results from diverse geographical areas suggest that industrial PCDD/F emission sources contribute to residential PCDD/F dust concentrations. Our emissions index could be improved by incorporating local

  19. Airborne asbestos in buildings.

    PubMed

    Lee, R J; Van Orden, D R

    2008-03-01

    The concentration of airborne asbestos in buildings nationwide is reported in this study. A total of 3978 indoor samples from 752 buildings, representing nearly 32 man-years of sampling, have been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result the presence of asbestos-containing materials (ACM). The average concentration of all airborne asbestos structures was 0.01structures/ml (s/ml) and the average concentration of airborne asbestos > or = 5microm long was 0.00012fibers/ml (f/ml). For all samples, 99.9% of the samples were <0.01 f/ml for fibers longer than 5microm; no building averaged above 0.004f/ml for fibers longer than 5microm. No asbestos was detected in 27% of the buildings and in 90% of the buildings no asbestos was detected that would have been seen optically (> or = 5microm long and > or = 0.25microm wide). Background outdoor concentrations have been reported at 0.0003f/ml > or = 5microm. These results indicate that in-place ACM does not result in elevated airborne asbestos in building atmospheres approaching regulatory levels and that it does not result in a significantly increased risk to building occupants.

  20. Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust.

    PubMed

    Perera, Inoka E; Sapko, Michael J; Harris, Marcia L; Zlochower, Isaac A; Weiss, Eric S

    2016-01-01

    Dispersible rock dust must be applied to the surfaces of entries in underground coal mines in order to inert the coal dust entrained or made airborne during an explosion and prevent propagating explosions. 30 CFR. 75.2 states that "… [rock dust particles] when wetted and dried will not cohere to form a cake which will not be dispersed into separate particles by a light blast of air …" However, a proper definition or quantification of "light blast of air" is not provided. The National Institute for Occupational Safety and Health (NIOSH) has, consequently, designed a dust dispersion chamber to conduct quantitative laboratory-scale dispersibility experiments as a screening tool for candidate rock dusts. A reproducible pulse of air is injected into the chamber and across a shallow tray of rock dust. The dust dispersed and carried downwind is monitored. The mass loss of the dust tray and the airborne dust measurements determine the relative dispersibility of the dust with respect to a Reference rock dust. This report describes the design and the methodology to evaluate the relative dispersibility of rock dusts with and without anti-caking agents. Further, the results of this study indicate that the dispersibility of rock dusts varies with particle size, type of anti-caking agent used, and with the untapped bulk density. Untreated rock dusts, when wetted and dried forming a cake that was much less dispersible than the reference rock dust used in supporting the 80% total incombustible content rule.

  1. Pulmonary Toxicity Studies of Lunar Dust in Rodents

    NASA Technical Reports Server (NTRS)

    Lam, Chiu-Wing; James, John T.

    2012-01-01

    NASA has been contemplating returning astronauts to the moon for long-duration habitation and research and using it as a stepping-stone to Mars. Other spacefaring nations are planning to send humans to the moon for the first time. The surface of the moon is covered by a layer of fine dust. Fine terrestrial dusts, if inhaled, are known to pose a health risk to humans. Some Apollo crews briefly exposed to moon dust that adhered to spacesuits and became airborne in the Lunar Module reported eye and throat irritation. The habitable area of any lunar landing vehicle or outpost would inevitably become contaminated with lunar dust. To assess the health risks of exposure of humans to airborne lunar dust, we evaluated the toxicity of Apollo 14 moon dust in animal lungs. Studies of the pulmonary toxicity of a dust are generally first done by intratracheal instillation (ITI) of aqueous suspensions of the test dust into the lungs of rodents. If a test dust is irritating or cytotoxic to the lungs, the alveolar macrophages, after phagocytizing the dust particles, will release cellular messengers to recruit white blood cells (WBCs) and to induce dilation of blood capillary walls to make them porous, allowing the WBCs to gain access to the alveolar space. The dilation of capillary walls also allows serum proteins and water entering the lung. Besides altering capillary integrity, a toxic dust can also directly kill the cells that come into contact with it or ingest it, after which the dead cells would release their contents, including lactate dehydrogenase (a common enzyme marker of cell death or tissue damage). In the treated animals, we lavaged the lungs 1 and 4 weeks after the dust instillation and measured the concentrations of these biomarkers of toxicity in the bronchioalveolar lavage fluids to determine the toxicity of the dust. To assess whether the inflammation and cellular injury observed in the biomarker study would lead to persistent or progressive histopathological

  2. Investigation of Airborne Chemical Concentrations in Certain Work Areas of Naval Air Rework Facility at North Island, California

    DTIC Science & Technology

    1976-12-01

    and leading edge abrasive strips, etc. In the process of doing these jobs, it is necessary to strip and clean surfaces and to prepare them for...cyanide sump i3 another possible source of hydrogen cyanide. The possibility of "accidents" or human failure could lead to conditions where appreciable...termining concentrations of toxic gases and vapors. It has been proven through extensive use by leading industrial companies and government agencies

  3. Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City.

    PubMed

    Ríos, B; Torres-Jardón, R; Ramírez-Arriaga, E; Martínez-Bernal, A; Rosas, I

    2016-05-01

    Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized

  4. Use of Cokriging to Improve Spatial Resolution of Ambient Airborne Contaminant Concentration Estimates in Detroit and Windsor

    NASA Astrophysics Data System (ADS)

    Lemke, L. D.; Bobryk, S. M.; Xu, X.

    2010-12-01

    A combination of active and passive air sampling devices was deployed to measure ambient air quality over a two-week period during September 2008 in Detroit, Michigan, USA and Windsor, Ontario, Canada. Passive diffusion monitors were used to measure nitrogen dioxide (NO2), sulfur dioxide (SO2) and 26 volatile organic compounds (VOCs) at 100 sampling sites with an approximate spacing of 1 per 5 km2. Active samplers utilizing a pump were collocated at 50 of the passive sites to sample particulate matter (PM) and 23 polycyclic aromatic hydrocarbons (PAHs) at an approximate sample density of 1 per 10 km2. The field campaign yielded acceptable data at 98 of the 100 passive monitoring sites. However, pump failures and power outages limited acceptable data to only 38 out of 50 active sites and the intended spatial coverage was not achieved. The utility of cokriging was therefore investigated as a means of improving PAH and PM concentration estimates by using more densely spaced passive sampler analyte concentrations as secondary information. Moderate positive correlation coefficients (p<0.05) were observed between total PAHs and NO2 (0.603), total PAHs and benzene (0.502), and PM1-2.5 and NO2 (0.555) in the study area, suggesting that NO2 and benzene could be used as non-exhaustive secondary data for cokriging. Variogram analysis was performed to specify the cross-covariance structure between each pair of pollutants using a linear model of coregionalization. Concentration maps produced through both ordinary kriging (OK) and ordinary cokriging (OCK) were compared and statistical metrics were used to quantify improvement in estimates for sampled points attributable to cokriging. Scatter plots of measured vs. estimated values indicate that both OK and OCK were able to reliably predict concentrations near measurement points. Modest improvement in cross validation correlation coefficients and residual error statistics were observed for PAH cokriged with NO2 and benzene

  5. Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City

    NASA Astrophysics Data System (ADS)

    Ríos, B.; Torres-Jardón, R.; Ramírez-Arriaga, E.; Martínez-Bernal, A.; Rosas, I.

    2016-05-01

    Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized

  6. Airborne observed and receptor-oriented modelled urban increments of anthropogenic CO2, CO and NOX concentrations in the megacity of London in summer 2012

    NASA Astrophysics Data System (ADS)

    Font Font, Anna Maria; Morguí, Josep Anton; Lee, James; McQuaid, Jim B.; Barratt, Benjamin

    2014-05-01

    A better characterization of the emissions and the dynamics of anthropogenic CO2 in large-urban centres are needed to implement more effective mitigation measures to combat climate change. This study aims to establish a representative emissions ratio of anthropogenic CO2 (CO2ff) in the megacity of London using CO and NOX as tracers. Observations of CO2, CO and NOX mixing ratios obtained onboard the NERC-ARSF aircraft undertaken on 12 July 2012 over the city of London were used. Airborne observations were taken at ~380 m along four transects crossing London, two in the morning (10:30 to 12:30 GMT) and two in the afternoon (15:30-16:30 GMT). The ratio of the amounts of CO and CO2 in excess of natural abundances (denoted as ΔCO and ΔCO2, respectively) from the airborne observations was used to determine the fraction of CO2 derived from burning fossil fuels (CO2ff). Total observations of CO and CO2 were compared to NOX observations and background concentrations were determined as the intercept when NOX mixing ratios equalled zero derived from standardised major axis linear regression. Excess concentrations were calculated by subtracting total amounts minus the background. ΔCO showed good correlation with ΔCO2 in the morning transects (R=0.95) but not in the afternoon (R=-0.50). The mean (±1σ) CO/CO2ff was derived from linear regression using the morning measurements and valued 5.0±0.4 ppb ppm-1. Lagrangian Particle Dispersion (LPD) simulations in backward mode were undertaken to model urban increments of anthropogenic CO2 and CO and to calculate the emissions ratio from the emissions inventory EDGAR v4.2. The LPD model FLEXPART was run with the meteorological data from the European Centre for Medium-Range Weather Forecasts (spatial resolution of 0.2 x 0.2 degrees; 91 vertical levels) and multiplied with the EDGAR emissions inventory (spatial resolution 0.1 x 0.1 degrees) to obtain an increment at each receptor point along the transects. Annual and temporal

  7. Respirable dust control in grinding gray iron castings.

    PubMed

    O'Brien, D; Baron, P; Willeke, K

    1987-02-01

    High speed grinding of gray iron castings long has been associated with excessive exposure to crystalline silica. Not all workers engaged in these operations are protected by conventional ventilation techniques. Dust in the air that has been entrained by the spinning grinding wheel and not captured in the grinder hood has been postulated to be a major exposure source. A pilot grinding operation was constructed, and the size distribution and concentration of airborne particles were measured with the aerodynamic particle sizer (APS). Various control measures proved effective in reducing the respirable dust concentration: increased exhaust ventilation, and installation of baffles and/or the use of an air jet to deflect the entrained air stream. The concentration of respirable dust is the breathing zone was reduced approximately 20-fold through the combined use of increased ventilation, interior baffles, and an air jet. The air jet and baffle utilized at the base ventilation rate reduced the respirable dust concentration by a factor of three to four, whereas the baffle alone halved the concentration.

  8. Airborne Measurements of CO2 Column Concentration and Range Using a Pulsed Direct-Detection IPDA Lidar

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Ramanathan, Anand; Riris, Haris; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Weaver, Clark J.; Browell, Edward V.

    2013-01-01

    We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The lidar measures the atmospheric backscatter profiles and samples the shape of the 1,572.33 nm CO2 absorption line. We participated in the ASCENDS science flights on the NASA DC-8 aircraft during August 2011 and report here lidar measurements made on four flights over a variety of surface and cloud conditions near the US. These included over a stratus cloud deck over the Pacific Ocean, to a dry lake bed surrounded by mountains in Nevada, to a desert area with a coal-fired power plant, and from the Rocky Mountains to Iowa, with segments with both cumulus and cirrus clouds. Most flights were to altitudes >12 km and had 5-6 altitude steps. Analyses show the retrievals of lidar range, CO2 column absorption, and CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds, between cumulus clouds, and to stratus cloud tops. The retrievals shows the decrease in column CO2 due to growing vegetation when flying over Iowa cropland as well as a sudden increase in CO2 concentration near a coal-fired power plant. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption lineshape (averaged for 50 s) matched the predicted shapes to better than 1% RMS error. For 10 s averaging, the scatter in the retrievals was typically 2-3 ppm and was limited by the received signal photon count. Retrievals were made using atmospheric parameters from both an atmospheric model and from in situ temperature and pressure from the aircraft. The retrievals had no free parameters and did not use empirical adjustments, and >70% of the measurements passed screening and were used in analysis. The differences between the lidar-measured retrievals and in situ measured average CO2 column concentrations were <1.4 ppm for flight measurement altitudes >6 km.

  9. Improve dust capture on your surface drill

    SciTech Connect

    Page, S.J.; Listak, J.M.; Reed, R.

    2008-09-15

    Researchers have developed a model to describe airborne respirable dust (ARD) generation on surface coal mine drills. By measuring a few basic parameters and using a graph, a drill operator or engineer can estimate the relative severity of drill dust emissions as well as how much of a reduction in ARD can be obtained by changing any given parameter. 4 refs., 2 figs.

  10. WMO Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS): Research Implementation Status

    NASA Astrophysics Data System (ADS)

    Nickovic, Slobodan; Barrie, Leonard

    2010-05-01

    Strong winds cause lifting of large amounts of sand and dust from bare, dry soils into the atmosphere. For countries in and downwind of arid regions, airborne sand and dust presents serious risks to the environment, property and human health. Impacts on health include respiratory and cardio-vascular problems, eye infections and in some regions, diseases such as meningitis and valley fever. Dust can efficiently carry irritating spores, bacteria, viruses and persistent organic pollutants. It can also efficiently transport nutrients to parts of the world oceans and affect marine biomass production. Other impacts include negative effects on the ground transport, aviation, agriculture and visibility. The Inter-governmental Panel on Climate Change (IPCC) recognizes dust as a major component of the atmospheric aerosol that is an essential climate variable. Dust aerosol has important effects on weather through feedback on atmospheric dynamics, clouds and precipitation formation. Approximately 15 centres around the world provide sand and dust research operational forecasts. Many are operated by national meteorological services of the World Meteorological Organization (WMO). Sand and dust storm models can substantially reduce risk by providing dust concentration predictions for several days in advance. Numerical weather prediction systems that drive these models use complex parameterizations and assimilation of satellite, and surface-based observations to predict winds, clouds, precipitation and dust mobilization, transport, and removal from the atmosphere. Sand and dust forecast products contribute to the mitigation and reduction of risk through research based advances in understanding and forecasting products. Observations of sand and dust are made by many agencies and some of them are being coordinated globally through the WMO Global Atmosphere Watch (GAW) programme. In 2006, WMO and partners initiated the implementation of the Sand and Dust Storm Warning Advisory and

  11. Concentration and emission sources of airborne metals in particulate matter in the industrial district of Médio Paraíba, state of Rio de Janeiro, Brazil.

    PubMed

    Loyola, Josiane; de Almeida, Pierre Batista; Quiterio, Simone Lorena; Sousa, Célia Regina; Arbilla, Graciela; Escaleira, Viviane; de Carvalho, Maria Isabel; dos Santos Amaral Gomes da Silva, Alzira

    2006-11-01

    Total suspended particles and 12 airborne metals were determined in 4 sampling sites in the industrial region of Médio Paraíba, Brazil. The geometrical means for the four sampling locals were (in units of microg/m3): 65.9 in Barra Mansa, 57.3 in Jardim Paraíba (Volta Redonda), 41.7 in Resende, and 48.9 in Volta Grande (Volta Redonda). These values are lower than levels previously determined in urban and industrial locals of the Metropolitan Area of Rio de Janeiro. For metals, the higher concentrations were obtained for Ca, Zn, Al, Fe, and Mg. Ca, Zn, and Al levels are higher than those determined in other industrial areas. These three metals are used in steel manufacturing, the main economical activity of the region. Enrichment factors for Zn, Cu, Cd, and Pb are higher than 10, suggesting an industrial input. Statistical analysis show a high correlation among Ca, Mg, Zn, Cr, Al, Mn, and Fe, all of them used as raw materials in steel manufacturing and/or accumulated as industrial blast furnace slag and steelworks slag.

  12. Assessment of bioaerosols and inhalable dust exposure in Swiss sawmills.

    PubMed

    Oppliger, Anne; Rusca, Sophie; Charrière, Nicole; Vu Duc, Trinh; Droz, Pierre-Olivier

    2005-07-01

    An assessment of wood workers' exposure to airborne cultivable bacteria, fungi, inhalable endotoxins and inhalable organic dust was performed at 12 sawmills that process mainly coniferous wood species. In each plant, samples were collected at four or five different work sites (debarking, sawing, sorting, planing and sawing cockpit) and the efficiency of sampling devices (impinger or filter) for determining endotoxins levels was evaluated. Results show that fungi are present in very high concentrations (up to 35 000 CFU m(-3)) in all sawmills. We also find that there are more bioaerosols at the sorting work site (mean +/- SD: 7723 +/- 9919 CFU m(-3) for total bacteria, 614 +/- 902 CFU m(-3) for Gram-negative, 19 438 +/- 14 246 CFU m(-3) for fungi, 7.0 +/- 9.0 EU m(-3) for endotoxin and 2.9 +/- 4.8 g m(-3) for dust) than at the sawing station (mean +/- SD: 1938 +/- 2478 CFU m(-3) for total bacteria, 141 +/- 206 CFU m(-3) for Gram-negative, 12 207 +/- 10 008 CFU m(-3) for fungi, 2.1 +/- 1.9 EU m(-3) for endotoxin and 0.75 +/- 0.49 mg m(-3) for dust). At the same time, the species composition and concentration of airborne Gram-negative bacteria were studied. Penicillinium sp. were the predominant fungi, while Bacillus sp. and the Pseudomonadacea family were the predominant Gram-positive and Gram-negative bacteria encountered, respectively.

  13. Parameterization of gaseous constituencies concentration profiles in the planetary boundary layer as required in support of airborne and satellite borne sensors

    NASA Technical Reports Server (NTRS)

    Kindle, E. C.; Condon, E.; Casas, J.

    1976-01-01

    The research to develop the capabilities for sensing air pollution constituencies using satellite or airborne remote sensors is reported. Sensor evaluation and calibration are analyzed including data reduction. The proposed follow-on research is presented.

  14. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  15. 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.

  16. Dust mite, cockroach, cat, and dog allergen concentrations in homes of asthmatic children in the northeastern United States: impact of socioeconomic factors and population density.

    PubMed

    Leaderer, Brian P; Belanger, Kathleen; Triche, Elizabeth; Holford, Theodore; Gold, Diane R; Kim, Young; Jankun, Thomas; Ren, Ping; McSharry Je, Jean-ellen; Platts-Mills, Thomas A E; Chapman, Martin D; Bracken, Michael B

    2002-04-01

    Home exposures to aeroallergens are an important environmental factor in allergic sensitization and in the development and exacerbation of asthma. We assessed variations in home concentrations of dust mite, cockroach, cat, and dog allergens in dust collected in the main living areas of asthmatics' homes by family income, mother's education, dwelling type, population density, household population density, and ethnicity in Connecticut and south-central Massachusetts. Dust samples were collected at the time of home interview in 999 homes as part of an ongoing longitudinal birth cohort study of 1,002 infants and their asthmatic siblings. The analysis employed lower and upper cut points for group 1 dust mite (> or = 2.0 microg/g and > or = 10 microg/g), cockroach (> or = 1.0 U/g and > or = 4.0 U/g), cat (> or = 1.0 microg/g and > or = 8.0 ug/g), and dog (> or = 2.0 microg/g and > or = 10.0 microg/g) allergens. Subject residences were geocoded to assess population density from the U.S. Census, and multiple logistic regression was used to control for confounding. The portion of homes at the lower cut point for dust mite, cockroach, cat, and dog allergens were 46.9%, 24.9%, 42.2%, and 35.6%, respectively; the upper cut point for each of the allergens was reached in 22.4%, 13.4%, 21.0%, and 22.9% of the homes, respectively. In all, 86.0% of the homes had at least one allergen at the lower cut point, and 58.0% had at least one allergen at the upper cut point. Forty-nine percent of the homes had two or more allergens at the lower cut point, and 19.7% had two or more allergens at the upper cut point. Higher education of the mother, higher household income, living in a single-family home in a less densely populated area with fewer people per room, and being a white household were associated with elevated dust mite, cat, and dog allergens and low cockroach allergen. In contrast, low income, living in a multifamily home in a high population density area with a higher occupancy

  17. Relative Contributions of Agricultural Drift, Para-Occupational, and Residential Use Exposure Pathways to House Dust Pesticide Concentrations: Meta-Regression of Published Data

    PubMed Central

    Deziel, Nicole C.; Freeman, Laura E. Beane; Graubard, Barry I.; Jones, Rena R.; Hoppin, Jane A.; Thomas, Kent; Hines, Cynthia J.; Blair, Aaron; Sandler, Dale P.; Chen, Honglei; Lubin, Jay H.; Andreotti, Gabriella; Alavanja, Michael C. R.; Friesen, Melissa C.

    2016-01-01

    Background: Increased pesticide concentrations in house dust in agricultural areas have been attributed to several exposure pathways, including agricultural drift, para-occupational, and residential use. Objective: To guide future exposure assessment efforts, we quantified relative contributions of these pathways using meta-regression models of published data on dust pesticide concentrations. Methods: From studies in North American agricultural areas published from 1995 to 2015, we abstracted dust pesticide concentrations reported as summary statistics [e.g., geometric means (GM)]. We analyzed these data using mixed-effects meta-regression models that weighted each summary statistic by its inverse variance. Dependent variables were either the log-transformed GM (drift) or the log-transformed ratio of GMs from two groups (para-occupational, residential use). Results: For the drift pathway, predicted GMs decreased sharply and nonlinearly, with GMs 64% lower in homes 250 m versus 23 m from fields (interquartile range of published data) based on 52 statistics from seven studies. For the para-occupational pathway, GMs were 2.3 times higher [95% confidence interval (CI): 1.5, 3.3; 15 statistics, five studies] in homes of farmers who applied pesticides more recently or frequently versus less recently or frequently. For the residential use pathway, GMs were 1.3 (95% CI: 1.1, 1.4) and 1.5 (95% CI: 1.2, 1.9) times higher in treated versus untreated homes, when the probability that a pesticide was used for the pest treatment was 1–19% and ≥ 20%, respectively (88 statistics, five studies). Conclusion: Our quantification of the relative contributions of pesticide exposure pathways in agricultural populations could improve exposure assessments in epidemiologic studies. The meta-regression models can be updated when additional data become available. Citation: Deziel NC, Beane Freeman LE, Graubard BI, Jones RR, Hoppin JA, Thomas K, Hines CJ, Blair A, Sandler DP, Chen H, Lubin

  18. 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

  19. 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

  20. Hebes Chasma Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located in Hebes Chasma.

    Image information: VIS instrument. Latitude -1.4, Longitude 286.6 East (73.4 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.