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Sample records for air fall dust

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

    PubMed Central

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

    2014-01-01

    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. PMID:24469149

  2. An investigation of dust generation by free falling powders.

    PubMed

    Heitbrink, W A; Baron, P A; Willeke, K

    1992-10-01

    To identify the dust generation processes, aluminum oxide powder was dropped as a free falling slug in a test chamber. The effect of the slug's mass, diameter, and drop height upon the aerosol concentration and size distribution was measured with an aerodynamic particle sizer. To differentiate between aerosol generated during the free fall and at the end of the fall, the slug was dropped either onto a flat surface or into a container of water that suppressed dust generation associated with the impact at the end of the fall. Aerosol generation occurred during the slug's free fall as well as at the end of the fall. The falling solid induced an airflow that followed the falling solid to the end of the fall. This induced airflow contained the aerosol generated during the free fall. At the end of the free fall, the induced airflow, combined with air jets created on impact, dispersed the aerosol throughout the test chamber. Additional measurements were made by using "neutral buoyancy" helium-filled bubbles to visualize the airflow in the test chamber. The airflow and ensuing turbulence were sufficient to keep large, inspirable particles suspended throughout the test chamber for periods greater than 10 min. During experimental work, the effect of drop height, mass, and slug diameter upon aerosol generation by a single slug of powder was studied. The results indicated that the manner in which a powder is handled may be as important as material dustiness as measured by a dustiness tester. Aerosol generation can be reduced by minimizing the contact between the falling powder and the air. PMID:1456205

  3. Characterization of mineralogy and surface zeta potential of atmospheric dust fall in northwest China

    NASA Astrophysics Data System (ADS)

    Dong, Fa-Qin; Chen, Wu; Dai, Qun-Wei; Deng, Yue-Quan; He, Ping; He, Xiao-Chun; Tang, Jun; Liu, Li-Zhu; He, Hua

    2015-06-01

    The mineralogy characterization of dust fall in atmosphere is important in understanding and improving air quality. In this paper, dust fall samples were collected in the suburb of four areas of northwest China during April to May 2012. The size distribution, mineral phase and composition, morphology, and surface charge of dust fall were investigated, respectively, by particle size analyzer, X-ray powder diffraction spectrometer (XRD), scanning electron microscopy (SEM), and zeta potential analyzer. The average volume size of dust fall was from 59.17 to 62.88 μm, and the dust fall in Tuoketuo County of Inner Mongolia Autonomous Region had the finest particles (59.17 μm), while the number percentage of fine particulate matter (<1.0 μm) in dusts was about 88.36 % of total particles. The main minerals of dust fall samples are composed of quartz, calcilte, muscotive, albite, clinochlore, and gypsum. And four dust fall samples had the same main mineral phase. Minerals of surface soil were identified as an important source of atmospheric dust fall. The morphological of the atmospheric dust fall presented irregular square, sphere, agglomerate elongated particles, and granular aggregates. Zeta potentials of four dust fall samples were negative in tested pH range. Moreover, their zeta potentials decreased with increasing pH of the solution. The surface charge of dust fall was strongly affected by the quantity of carbonate minerals (calcite and dolomite) in samples. The simulated zeta potential result of multimineral dusts indicated that the magnitude and tendencies of dust's zeta potential were dominated by the main mineral phase in dust fall.

  4. Perchlorate in dust fall and indoor dust in Malta: An effect of fireworks.

    PubMed

    Vella, Alfred J; Chircop, Cynthia; Micallef, Tamara; Pace, Colette

    2015-07-15

    We report on the presence of perchlorate in the settleable dust of Malta, a small central Mediterranean island. Both dust fall collected directly as it precipitated from atmosphere over a period of one month and deposited indoor dust from domestic residences were studied. Perchlorate was determined by ion chromatography of water extracts of the collected dusts. Dust fall was collected from 43 towns during 2011 to 2013 and indoor dust was sampled from homes in the same localities. Perchlorate was detected in 108 of 153 samples of dust fall (71%) and in 28 of 37 indoor dust samples (76%). Detectable perchlorate in dust fall ranged from 0.52μgg(-1) to 561μgg(-1) with a median value of 6.2μgg(-1); in indoor dust, levels were from 0.79μgg(-1) to 53μgg(-1) with a median value of 7.8μgg(-1), the highest recorded anywhere to date. Statistical analysis suggested that there was no significant difference in perchlorate content of indoor dust and dust fall. Perchlorate levels in dust fall escalate during the summer in response to numerous religious feasts celebrated with fireworks and perchlorate persists at low μgg(-1) concentrations for several months beyond the summer festive period. In Malta, perchlorate derives exclusively from KClO4, imported for fireworks manufacture. Its residue in dust presents an exposure risk to the population, especially via ingestion by hand to mouth transfer. Our results suggest that wherever intensive burning of fireworks takes place, the environmental impact may be much longer lived than realised, mainly due to re-suspension and deposition of contaminated settled dust in the urban environment. PMID:25828411

  5. Using thermal infrared (TIR) data to characterize dust sources, dust fall and the linkage to climate in the Middle East

    NASA Astrophysics Data System (ADS)

    Mohammad, R.; Ramsey, M.; Scheidt, S. P.

    2010-12-01

    Prior to mineral dust deposition affecting albedo, aerosols can have direct and indirect effects on local to regional scale climate by changing both the shortwave and longwave radiative forcing. In addition, mineral dust causes health hazards, such as respiratory-related illnesses and deaths, loss of agricultural soil, and safety hazards to aviation and motorists due to reduced visibility. Previous work utilized satellite and ground-based TIR data to describe the direct longwave radiative effect of the Saharan Air Layer (SAL) over the Atlantic Ocean originating from dust storms in the Western Sahara. TIR emission spectroscopy was used to identify the spectral absorption features of that dust. The current research focuses on Kuwait and utilizes a comprehensive set of spatial, analytical and geological tools to characterize dust emissions and its radiative effects. Surface mineral composition maps for the Kuwait region were created using ASTER images and GIS datasets in order to identify the possible sources of wind-blown dust. Backward trajectory analysis using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests the dust source areas were located in Iraq, Syria, Jordan and Saudi Arabia. Samples collected from two dust storms (May and July 2010) were analyzed for their mineral composition and to validate the dust source areas identified by the modeling and remote sensing analysis. These air fall dust samples were collected in glass containers on a 13 meter high rooftop in the suburb of Rumaithiya in Kuwait. Additional samples will be collected to expand the analysis and their chemical compositions will be characterized by a combination of laboratory X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM) and TIR emission spectroscopy. The overarching objective of this ongoing research is to both characterize the effects of mineral dust on climate as well as establish a predictive tool that can identify dust storm sources and

  6. Wetting Behavior of Hydrophobic Dust and Dust-Fall Theory of Fine Droplets

    NASA Astrophysics Data System (ADS)

    Kou, Bao-Fu; Liu, Qiu-Zu

    2015-12-01

    The wetting behavior of droplets on the surfaces of hydrophobic coal slices is measured with a CCD camera and simulated with the volume of fluid (VOF) numerical method. Experimental results reveal that the contact angle changes exponatially with time and the wettability decreases with the increasing rough microstructures of coal slice surfaces. There is a good agreement between numerical simulations and experimental results. Meanwhile, it is found that droplet with a smaller volume can enhance the hydrophilic. The dust-fall theory of fine droplets is useful to improve the wettability of dust and enlarge the contact ratio between dust and droplets, which can help to design wet-type dust-fall equipment and provide new way for the control of respiratory dust.

  7. Research on flux of dry atmospheric falling dust and its characterization in a subtropical city, Guangzhou, South China

    PubMed Central

    Zhao, Jinping; Song, Jianzhong; Ma, Shexia; Sheng, Guoying; Fu, Jiamo

    2010-01-01

    Guangzhou is the central city in the Pearl River Delta (PRD), China, and is one of the most polluted cities in the world. To characterize the ambient falling dust pollution, two typical sampling sites: urban (Wushan) and suburban (University Town) areas in Guangzhou city were chosen for falling dust collection over 1 year at time intervals of 1 or 2 months. The flux of dry deposition was calculated. In addition, mineral composition and morphology of atmospheric falling dust were studied by X-ray diffraction, scanning electron microscopy, and microscopic observation. The results revealed that the dust flux in Guangzhou city was 3.34–3.78 g/(m2 month) during the study period. The main minerals in the dust were quartz, illite, calcite, kaolinite, gypsum, plagioclase, dolomite, and amorphous matter. The morphological types included grained and flaky individual minerals, chain-like aggregates, spherical flying beads, and irregular aggregates, with the chain-like and spherical aggregates indicators of industrial ash. The major dusts were derived from industrial and construction activities. The gypsum present in the dust collected in winter season was not only derived from cement dust but may also have originated from the reaction of calcic material with sulfuric acids resulting from photooxidation of SOx and NOx, which confirmed serious air pollution due to SOx and NOx in Guangzhou. The abatement of fossil fuel combustion emissions and construction dust will have a significant beneficial effect on dust reduction. PMID:20700381

  8. Air pollution by concrete dust from the Great Hanshin Earthquake.

    PubMed

    Gotoh, Takao; Nishimura, Takashi; Nakata, Minoru; Nakaguchi, Yuzuru; Hiraki, Keizo

    2002-01-01

    Air pollution in the areas affected by the Great Hanshin Earthquake (Hyogo, Japan) of 17 Jan. 1995 was quite serious. We performed three investigations of dust. In the first investigation, we measured the total suspended particulate (TSP) concentration in the greatly damaged areas, located around the Sannomiya Station where a few hundred thousand people walked by during the daytime of 3 February. The maximum concentration at five points reached 150 microg/m3. In the second investigation, eight samples, which were classified into three groups (concrete, mortar, and soil dusts) as sources, were analyzed elementally by X-ray fluorescence. The elements found in concrete dust (Ca and S) were similar to those found in mortar dust. These differed from those found in soil dust (Ti, Fe, and Zr). The elements found in soil dust were important from the viewpoint of heavy metal contamination. In the third investigation, the alkalinity of concrete dust was observed by dissolution. This solution was equivalent to pH 11 to 12 and electrical conductivity 20 to 30 microS/m. We suspect that the alkaline component in the dust from debris in all the devastated areas was approximately comparable with the alkaline solution by which the acid rain falling over the Hanshin district of Osaka Megalopolis in one year could be neutralized into water of pH 7.0. PMID:12026073

  9. Diffusive Plasma Dechucking Method for Wafers to Reduce Falling Dust Particles

    NASA Astrophysics Data System (ADS)

    Jun, Hyun-Su

    2013-06-01

    A plasma dechucking method capable of effectively eliminating dust particles created during the plasma process was developed. Referred to as diffusive plasma dechucking (DPD), the method reduces the plasma potential and includes an argon gas purge to remove dust particles floating on top of the sheath after the main process. Experimental results indicate that DPD reduces the amount of falling dust particles after the process by approximately 50-80%. To analyze these results quantitatively, the Coulomb force and the neutral drag force exerted on the dust particles were considered. In addition, dust particle exhaust conditions were proposed with respect to dust particle size, plasma potential, and spatial electric field.

  10. Lead and Other Heavy Metals in Dust Fall from Single-Family Housing Demolition

    PubMed Central

    Cali, Salvatore; Welch, Alison; Catalin, Bogdan; Dixon, Sherry L.; Evens, Anne; Mucha, Amy P.; Vahl, Nicole; Erdal, Serap; Bartlett, John

    2013-01-01

    Objective We measured lead and other heavy metals in dust during older housing demolition and effectiveness of dust suppression. Methods We used American Public Housing Association Method 502 and U.S. Environmental Protection Agency Methods SW3050B and SW6020 at 97 single-family housing demolition events with intermittent (or no) use of water to suppress dust at perimeter, non-perimeter, and locations without demolition, with nested mixed modeling and tobit modeling with left censoring. Results The geometric mean (GM) lead dust fall during demolition was 6.01 micrograms of lead per square foot per hour (μg Pb/ft2/hour). GM lead dust fall was 14.18 μg Pb/ft2/hour without dust suppression, but declined to 5.48 μg Pb/ft2/hour (p=0.057) when buildings and debris were wetted. Significant predictors included distance, wind direction, and main street location. At 400 feet, lead dust fall was not significantly different from background. GM lead concentration at demolition (2,406 parts per million [ppm]) was significantly greater than background (GM=579 ppm, p=0.05). Arsenic, chromium, copper, iron, and manganese demolition dust fall was significantly higher than background (p<0.001). Demolition of approximately 400 old housing units elsewhere with more dust suppression was only 0.25 μg Pb/ft2/hour. Conclusions Lead dust suppression is feasible and important in single-family housing demolition where distances between houses are smaller and community exposures are higher. Neighbor notification should be expanded to at least 400 feet away from single-family housing demolition, not just adjacent properties. Further research is needed on effects of distance, potential water contamination, occupational exposures, and water application. PMID:24179257

  11. Dust-air pollution dynamics over the eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Abdelkader, M.; Metzger, S.; Mamouri, R. E.; Astitha, M.; Barrie, L.; Levin, Z.; Lelieveld, J.

    2015-08-01

    Interactions of desert dust and air pollution over the eastern Mediterranean (EM) have been studied, focusing on two distinct dust transport events on 22 and 28 September 2011. The atmospheric chemistry-climate model EMAC has been used at about 50 km grid spacing, applying an online dust emission scheme and calcium as a proxy for dust reactivity. EMAC includes a detailed tropospheric chemistry mechanism, aerosol microphysics and thermodynamics schemes to describe dust "aging". The model is evaluated using ground-based observations for aerosol concentrations and aerosol optical depth (AOD) as well as satellite observations. Simulation results and back trajectory analysis show that the development of synoptic disturbances over the EM can enhance dust transport from the Sahara and Arabian deserts in frontal systems that also carry air pollution to the EM. The frontal systems are associated with precipitation that controls the dust removal. Our results show the importance of chemical aging of dust, which increases particle size, dust deposition and scavenging efficiency during transport, overall reducing the lifetime relative to non-aged dust particles. The relatively long travel periods of Saharan dust result in more sustained aging compared to Arabian dust. Sensitivity simulations indicate 3 times more dust deposition of aged relative to pristine dust, which significantly decreases the dust lifetime and loading.

  12. Air compliance falls short without CEMs

    SciTech Connect

    Wagner, G.H. II

    1994-06-01

    Four titles of the Clean Air Act Amendments of 1990 refer to or require the use of continuous emission moniotrs (CEMs). The code of Federal regulations, Title 40, part 60, Appendix B lists the Performance Specifications for the design, installation and initial performance evaluation of CEMs. Emission monitors are required by 40 CFR 503 for sewage sludge incinerators and by 40 CFR 264/266 foir boilers and industrial furnaces. Technology advances of CEMs are discussed.

  13. DDT and detonation waves in dust-air mixtures

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Grönig, H.; van de Ven, A.

    This paper summarizes the studies of DDT and stable detonation waves in dust-air mixtures at the Stosswellenlabor of RWTH Aachen. The DDT process and propagation mechanism for stable heterogeneous dust detonations in air are essentially the same as in the oxygen environment studied previously. The dust DDT process in tubes is composed of a reaction compression stage followed by a reaction shock stage as the pre-detonation process. The transverse waves that couple the shock wave and the chemical energy release are responsible for the propagation of a stable dust-air detonation. However, the transverse wave spacing of dust-air mixtures is much larger. Therefore, DDT and propagation of a stable detonation in most industrial and agricultural, combustible dust-air mixtures require a tube that has a large diameter between 0.1 m and 1 m and a sufficient length-diameter ratio beyond 100, when an appropriately strong initiation energy is used. Two dust detonation tubes, 0.14 m and 0.3 m in diameter, were used for observation of the above-mentioned results in cornstarch, anthraquinone and aluminum dust suspended in air. Smoked-foil technique was also used to measure the cellular structure of dust detonations in the 0.3 m detonation tube.

  14. Spectroscopic Characterization of Dust-Fall Samples Collected from Greater Cairo, Egypt.

    PubMed

    Shaltout, Abdallah A; Allam, Mousa A; Mostafa, Nasser Y; Heiba, Zein K

    2016-04-01

    This work aimed to characterize dust-fall samples collected from street's trees in Greater Cairo (GC), Egypt, and its surroundings by different spectroscopic techniques, namely; X-ray diffraction (XRD), attenuated total-reflection Fourier transform infrared (ATR-FTIR), particle-size analyzer, and scanning electron microscopy (SEM) combined with energy dispersive X-ray measurements. Samples were collected from 19 different locations inside and outside of GC. Quantitative phase analysis of the dust-fall samples was performed using the Rietveld method. Results showed that the most frequently observed phases in the dust-fall samples were calcite (CaCO3), dolomite (CaMg(CO3)2), gypsum (CaSO4·2H2O), and quartz (SiO2) with average concentrations of 39 ± 16, 8 ± 7, 22 ± 13, and 33 ± 14 wt%, respectively. The occurrence of these constituents referred to a combination of different anthropogenic and natural sources. The ATR-FTIR results are in good agreements with XRD data of the different observed phases. Based on the SEM and particle-size measurements, quantitative determination of the particle-size distribution was described. It was found that not only the large-sized particles are deposited but also the small-sized ones (PM10 and PM2.5). In addition, the particle size of the collected dust-fall samples varied from 0.1 to 200 µm with an average particle size of 17.36 µm; however, the particle size ranged from 2.5 to 40 µm predominated in all of the dust-fall samples. PMID:26710766

  15. Efficiency of dust sampling inlets in calm air.

    PubMed

    Breslin, J A; Stein, R L

    1975-08-01

    Measurement of airborne dust concentrations usually involves drawing a sample of the dust-laden air into the measuring instrument through an inlet. Even if the surrounding air is calm, theoretical calculations predict that large particles may not be sampled accurately due to the combined effects of gravity and inertia on the particles near the sampling inlet. Tests were conducted to determine the conditions of particle size, inlet radius, and flow rare necessary for accurate dust sampling. A coal-dust aerosol was sampled simultaneously through inlets of different diameters at the same volume flow-rate and collected on filters. The dust was removed from the filters and the particles were counted and sized with a Coulter counter. Results showed that published criteria for inlet conditions for correct sampling are overly restrictive and that respirable-size particles are sampled correctly in the normal range or operation of most dust sampling instruments. PMID:1227283

  16. Composition and source apportionment of dust fall around a natural lake.

    PubMed

    Latif, Mohd Talib; Ngah, Sofia Aida; Dominick, Doreena; Razak, Intan Suraya; Guo, Xinxin; Srithawirat, Thunwadee; Mushrifah, Idris

    2015-07-01

    The aim of this study was to determine the source apportionment of dust fall around Lake Chini, Malaysia. Samples were collected monthly between December 2012 and March 2013 at seven sampling stations located around Lake Chini. The samples were filtered to separate the dissolved and undissolved solids. The ionic compositions (NO3-, SO4(2-), Cl- and NH4+) were determined using ion chromatography (IC) while major elements (K, Na, Ca and Mg) and trace metals (Zn, Fe, Al, Ni, Mn, Cr, Pb and Cd) were determined using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the average concentration of total solids around Lake Chini was 93.49±16.16 mg/(m2·day). SO4(2-), Na and Zn dominated the dissolved portion of the dust fall. The enrichment factors (EF) revealed that the source of the trace metals and major elements in the rain water was anthropogenic, except for Fe. Hierarchical agglomerative cluster analysis (HACA) classified the seven monitoring stations and 16 variables into five groups and three groups respectively. A coupled receptor model, principal component analysis multiple linear regression (PCA-MLR), revealed that the sources of dust fall in Lake Chini were dominated by agricultural and biomass burning (42%), followed by the earth's crust (28%), sea spray (16%) and a mixture of soil dust and vehicle emissions (14%). PMID:26141887

  17. Air-conditioner filters enriching dust mites allergen.

    PubMed

    Zhan, Xiaodong; Li, Chaopin; Xu, Haifeng; Xu, Pengfei; Zhu, Haibin; Diao, Jidong; Li, Na; Zhao, Beibei

    2015-01-01

    We detected the concentration of dust mites allergen (Der f1 & Der p1) in the air of different places before and after the starting of air-conditioners in Wuhu City, Anhui, China, and to discuss the relation between the dust mites allergen in air-conditioner filters and the asthma attack. The dust samples were collected from the air-conditioner filters in dining rooms, shopping malls, hotels and households respectively. Concentrations of dust mites major group allergen 1 (Der f 1, Der p1) were detected with enzyme linked immunosorbent assay (ELISA), and the dust mite immune activities were determined by dot-ELISA. The concentration of Der f1 in dining rooms, shopping malls, hotels and households was 1.52 μg/g, 1.24 μg/g, 1.31 μg/g and 1.46 μg/g respectively, and the concentration of Der p1 in above-mentioned places was 1.23 μg/g, 1.12 μg/g, 1.16 μg/g and 1.18 μg/g respectively. The concentration of Der f1 & Der p1 in air was higher after the air-conditioners starting one hours later, and the difference was significant (P<0.05, respectively). Additionally, dot-ELISA findings revealed that the allergen extracted from the dust was capable of reacting with IgE from the sera of asthma mice allergic to dust mites. The study concludes that air-conditioner filters can enrich dust mites major group allergen, and the allergens can induce asthma. The air-conditioner filters shall be cleaned or replaced regularly to prevent or reduce accumulation of the dust mites and its allergens. PMID:26064381

  18. Air-conditioner filters enriching dust mites allergen

    PubMed Central

    Zhan, Xiaodong; Li, Chaopin; Xu, Haifeng; Xu, Pengfei; Zhu, Haibin; Diao, Jidong; Li, Na; Zhao, Beibei

    2015-01-01

    We detected the concentration of dust mites allergen (Der f1 & Der p1) in the air of different places before and after the starting of air-conditioners in Wuhu City, Anhui, China, and to discuss the relation between the dust mites allergen in air-conditioner filters and the asthma attack. The dust samples were collected from the air-conditioner filters in dining rooms, shopping malls, hotels and households respectively. Concentrations of dust mites major group allergen 1 (Der f 1, Der p1) were detected with enzyme linked immunosorbent assay (ELISA), and the dust mite immune activities were determined by dot-ELISA. The concentration of Der f1 in dining rooms, shopping malls, hotels and households was 1.52 μg/g, 1.24 μg/g, 1.31 μg/g and 1.46 μg/g respectively, and the concentration of Der p1 in above-mentioned places was 1.23 μg/g, 1.12 μg/g, 1.16 μg/g and 1.18 μg/g respectively. The concentration of Der f1 & Der p1 in air was higher after the air-conditioners starting one hours later, and the difference was significant (P<0.05, respectively). Additionally, dot-ELISA findings revealed that the allergen extracted from the dust was capable of reacting with IgE from the sera of asthma mice allergic to dust mites. The study concludes that air-conditioner filters can enrich dust mites major group allergen, and the allergens can induce asthma. The air-conditioner filters shall be cleaned or replaced regularly to prevent or reduce accumulation of the dust mites and its allergens. PMID:26064381

  19. Associations between PBDEs in office air, dust, and surface wipes.

    PubMed

    Watkins, Deborah J; McClean, Michael D; Fraser, Alicia J; Weinberg, Janice; Stapleton, Heather M; Webster, Thomas F

    2013-09-01

    Increased use of flame-retardants in office furniture may increase exposure to PBDEs in the office environment. However, partitioning of PBDEs within the office environment is not well understood. Our objectives were to examine relationships between concurrent measures of PBDEs in office air, floor dust, and surface wipes. We collected air, dust, and surface wipe samples from 31 offices in Boston, MA. Correlation and linear regression were used to evaluate associations between variables. Geometric mean (GM) concentrations of individual BDE congeners in air and congener specific octanol-air partition coefficients (Koa) were used to predict GM concentrations in dust and surface wipes and compared to the measured concentrations. GM concentrations of PentaBDEs in office air, dust, and surface wipes were 472pg/m(3), 2411ng/g, and 77pg/cm(2), respectively. BDE209 was detected in 100% of dust samples (GM=4202ng/g), 93% of surface wipes (GM=125pg/cm(2)), and 39% of air samples. PentaBDEs in dust and air were moderately correlated with each other (r=0.60, p=0.0003), as well as with PentaBDEs in surface wipes (r=0.51, p=0.003 for both dust and air). BDE209 in dust was correlated with BDE209 in surface wipes (r=0.69, p=0.007). Building (three categories) and PentaBDEs in dust were independent predictors of PentaBDEs in both air and surface wipes, together explaining 50% (p=0.0009) and 48% (p=0.001) of the variation respectively. Predicted and measured concentrations of individual BDE congeners were highly correlated in dust (r=0.98, p<0.0001) and surface wipes (r=0.94, p=002). BDE209 provided an interesting test of this equilibrium partitioning model as it is a low volatility compound. Associations between PentaBDEs in multiple sampling media suggest that collecting dust or surface wipes may be a convenient method of characterizing exposure in the indoor environment. The volatility of individual congeners, as well as physical characteristics of the indoor environment

  20. Associations between PBDEs in Office Air, Dust, and Surface Wipes

    PubMed Central

    Watkins, Deborah J.; McClean, Michael D.; Fraser, Alicia J.; Weinberg, Janice; Stapleton, Heather M.; Webster, Thomas F.

    2013-01-01

    Increased use of flame-retardants in office furniture may increase exposure to PBDEs in the office environment. However, partitioning of PBDEs within the office environment is not well understood. Our objectives were to examine relationships between concurrent measures of PBDEs in office air, floor dust, and surface wipes. We collected air, dust, and surface wipe samples from 31 offices in Boston, MA. Correlation and linear regression were used to evaluate associations between variables. Geometric mean (GM) concentrations of individual BDE congeners in air and congener specific octanol-air partition coefficients (Koa) were used to predict GM concentrations in dust and surface wipes and compared to the measured concentrations. GM concentrations of PentaBDEs in office air, dust, and surface wipes were 472 pg/m3, 2411 ng/g, and 77 pg/cm2, respectively. BDE209 was detected in 100% of dust samples (GM=4202 ng/g), 93% of surface wipes (GM=125 pg/cm2), and 39% of air samples. PentaBDEs in dust and air were moderately correlated with each other (r=0.60, p=0.0003), as well as with PentaBDEs in surface wipes (r=0.51, p=0.003 for both dust and air). BDE209 in dust was correlated with BDE209 in surface wipes (r=0.69, p=0.007). Building (three categories) and PentaBDEs in dust were independent predictors of PentaBDEs in both air and surface wipes, together explaining 50% (p=0.0009) and 48% (p=0.001) of the variation respectively. Predicted and measured concentrations of individual BDE congeners were highly correlated in dust (r=0.98, p<0.0001) and surface wipes (r=0.94, p=002). BDE209 provided an interesting test of this equilibrium partitioning model as it is a low volatility compound. Associations between PentaBDEs in multiple sampling media suggest that collecting dust or surface wipes may be a convenient method of characterizing exposure in the indoor environment. The volatility of individual congeners, as well as physical characteristics of the indoor environment

  1. Deformation of a water shell during free fall in air

    NASA Astrophysics Data System (ADS)

    Nakoryakov, V. E.; Kuznetsov, G. V.; Strizhak, P. A.

    2016-04-01

    The basic regularities of the change in the shape and sizes (the initial volume is 0.05-0.5 L) of a water shell are singled out in its deformation during free fall in air from a height of 3 m. The 3D recording of the basic stages of deformation (flattening of the shell, nucleation, growth, and destruction of bubbles, formation of the droplet cloud) is carried out using high-speed (up to 105 frames per second) Phantom V411 and Phantom Miro M310 video cameras and the program complex Tema Automotive (with the function of continuous tracking). The physical model of destruction of large water bodies is formulated at free fall with the formation of the droplet cloud.

  2. Impact of Asian Dust on Climate and Air Quality

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Tan, Qian; Diehl, Thomas; Yu, Hongbin

    2010-01-01

    Dust generated from Asian permanent desert and desertification areas can be efficiently transported around the globe, making significant radiative impact through their absorbing and scattering solar radiation and through their deposition on snow and ice to modify the surface albedo. Asian dust is also a major concern of surface air quality not only in the source and immediate downwind regions but also areas thousands of miles away across the Pacific. We present here a global model, GOCART, analysis of data from satellite remote sensing instrument (MODIS, MISR, CALIPSO, OMI) and other observations on Asian dust sources, transport, and deposition, and use the model to assess the Asian dust impact on global climate and air quality.

  3. Escaping the regulatory dust bowl: fugitive dust and the Clean Air Act

    SciTech Connect

    Probst, G.L.; Becker, R.E. Jr.

    1982-01-01

    The Environmental Protection Agency's (EPA's) regulatory program, as it relates to particulates, is overly complicated. In attempting to accommodate statutory language insensitive to particulate differences, after becoming aware of the varying effects of different-sized particles, EPA has developed an unworkable program. Although agricultural, recreational, transportation, and industrial activities contribute to the airborne dust (or, in the Clean Air Act vernacular, fugitive dust), this article focuses on mining activities. Surface mining inevitably stirs up considerable fugitive dust, and a description of mining activities in arid conditions, and how they fit in with a developing regulatory program, reveals a story of a national program that fails to provide for rational policy and regional flexibility. The article also recommends some regulatory and statutory solutions that could relatively easily correct EPA's fugitive dust program.

  4. Quantitative estimation of dust fall and smoke particles in Quetta Valley*

    PubMed Central

    Sami, Muhammad; Waseem, Amir; Akbar, Sher

    2006-01-01

    Tightening of air quality standards for populated urban areas has led to increasing attention to assessment of air quality management areas, where violation of air quality standards occurs, and development of control strategies to eliminate such violation of air quality standards. The Quetta urban area is very densely built and has heavy motorized traffic. The increase of emissions mainly from traffic and industry are responsible for the increase in atmospheric pollution levels during the last years. The dust examined in the current study was collected by both deposit gauge and Petri dish methods at various sites of Quetta Valley. Smoke particles were obtained by bladder method from the exhausts of various types of motor vehicles. The concentration of lead found in the smoke ranged from 1.5×10−6 to 4.5×10−6. PMID:16773727

  5. Falls

    MedlinePlus

    ... problems with circulation, thyroid or nervous systems. Some medicines make people dizzy. Eye problems or alcohol can be factors. Any of these things can make a fall more likely. Babies and young children are also at risk of falling - off ...

  6. Manganese and lead in dust fall accumulation in elementary schools near a ferromanganese alloy plant.

    PubMed

    Menezes-Filho, José Antonio; Souza, Karine O Fraga de; Rodrigues, Juliana L Gomes; Santos, Nathália Ribeiro Dos; Bandeira, Matheus de Jesus; Koin, Ng Lai; Oliveira, Sérgio S do Prado; Godoy, Ana Leonor P Campos; Mergler, Donna

    2016-07-01

    Previous studies have shown elevated airborne manganese (Mn) in villages adjacent to a Mn alloy production plant in Brazil and negative associations between biomarkers of Mn and children's cognition and behavior. Since small Mn particles may be carried for long distances, we measured manganese (Mn) and lead (Pb) dust fall accumulation in 15 elementary schools, located between 1.25 and 6.48km from the plant in the municipality of Simões Filho, Bahia, Brazil. Passive samplers (polyethylene Petri dishes) were set in interior and exterior environments. After 30 days, the samplers' content was solubilized with diluted nitric acid and Mn and Pb levels were analyzed by electrothermal absorption spectrometry. The overall geometric mean and range of Mn and Pb accumulation in dust fall (loading rates) were 1582μg Mn/m(2)/30 days (37-37,967) and 43.2μg Pb/m(2)/30 days (2.9-210.4). A logarithmic decrease in interior and exterior Mn loading rates was observed with distance from the ferro-manganese alloy plant. Multiple regression analyses of log-transformed Mn loading rate within the schools showed a positive association with Mn levels in outdoor dust, a negative association with distance from the plant; as well, wind direction (downwind>upwind) and school location (urban>rural) entered significantly into the model. For the interior school environments, located within a 2-km radius from the plant, loading rate was, on average, 190 times higher than the Mn levels reported by Gulson et al., (2014) in daycare centers in Sydney, Australia, using a similar method. Pb loading rates were not associated with distance from the plant and were lower than the rates observed in the same daycare centers in Sydney. Our findings suggest that a significant portion of the children in this town in Brazil may be exposed to airborne Mn at concentrations that may affect their neurodevelopment. PMID:27107708

  7. Dust and Air Quality Forecasting in the Eastern Caribbean

    NASA Astrophysics Data System (ADS)

    Sealy, A. M.; Reyes, A.; Farrell, D. A.

    2015-12-01

    Significant amounts of dust travel across the northern tropical Atlantic to the Caribbean every year from the Sahara region. These dust concentrations in the Caribbean often exceed United States Environmental Protection Agency (EPA) standards for particulate matter of 2.5 microns or less (PM 2.5) which could have serious implications for human health in the region. Air pollution has become a major issue in the Caribbean because of urban development, increased vehicle emissions and growing industrialisation. However, the majority of territories in the Caribbean do not have routine air quality monitoring programmes and several do not have or enforce air quality standards for PM2.5 and PM10. As a result, the Caribbean Institute for Meteorology and Hydrology (CIMH) has taken the initiative to provide dust and air quality forecasts for the Eastern Caribbean using the advanced WRF-Chem modeling system. The applications of the WRF-Chem modelling system at CIMH that are currently being focused on are the coupled weather prediction/dispersion model to simulate the release and transport of constituents, especially Saharan dust transport and concentration; and as a coupled weather/dispersion/air quality model with full interaction of chemical species with prediction of particulate matter (PM2.5 and PM10). This will include future applications in the prediction of ozone (O3) and ultraviolet (UV) radiation as well as examining dust radiative forcing and effects on atmospheric precipitation and dynamics. The simulations are currently initialised at 00Z for a seven day forecast and run at 36 km resolution with a planned second domain (at 12 km) for air quality forecasts. Preliminary results from this study will be presented and compared to other dust forecast models currently used in other regions. This work also complements in situ measurements at Ragged Point, Barbados (oldest dust record since 1965), Martinique, Guadeloupe, French Guiana and Puerto Rico. The goal of this study

  8. Simulation of spectral effects of Asian dusts on the AIRS radiances and its application to retrieval of dust properties

    NASA Astrophysics Data System (ADS)

    Han, Hyo-Jin; Sohn, Byung-Ju; Huang, Hung-Lung; Weisz, Elisabeth

    2010-11-01

    In order to examine the effect of Asian dusts and apply to retrieval of dust properties, radiances measured by AIRS were simulated using the RTTOV-9 model. The model has been implemented with new optical properties for Asian dusts; refractive indices of mineral dust in the OPAC library and size distribution of Asian dusts retrieved from 10 years of skyradiometer measurements at Dunhuang, China. The simulations were performed using the implemented model, but with specification of AOT and height of dust layers obtained from CALIOP measurements. In the simulations, surface and atmospheric temperatures are from AIRS level 2 products while surface emissivity is specified with UW/CIMSS monthly mean global infrared surface emissivity data. Results show that effect of Asian dusts on AIRS spectra is substantial over infrared window regions (i.e.: 3.7 - 4.1 μm, 8.8 - 9.3 μm, 10 - 13 μm) for moderate and strong dust cases (AOT >= 0.5), while surface effect is dominant for weak dust cases (AOT < 0.5). Over 10 - 13 μm and 3.6 - 4.1 μm ranges, the simulation performances are improved when the dust effect is added. However, on the spectral range of 8.8 - 9.3 μm, the simulation overestimates radiances in comparison with AIRS measurements, probably because the mineral dust composition of OPAC does not coincide with the Asian dust. The comparison of simulated radiances with AIRS measurements shows a comparable quality for both clear and dusty conditions on the 10 - 13 μm and 3.6 - 4.1 μm ranges, suggesting that results can be incorporated for developing dust retrieval algorithm from hyperspectral images such as AIRS and IASI.

  9. The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence.

    PubMed

    Mielke, Howard W; Zahran, Sammy

    2012-08-01

    We evaluate air Pb emissions and latent aggravated assault behavior at the scale of the city. We accomplish this by regressing annual Federal Bureau of Investigation aggravated assault rate records against the rise and fall of annual vehicle Pb emissions in Chicago (Illinois), Indianapolis (Indiana), Minneapolis (Minnesota), San Diego (California), Atlanta (Georgia), and New Orleans (Louisiana). Other things held equal, a 1% increase in tonnages of air Pb released 22 years prior raises the present period aggravated assault rate by 0.46% (95% CI, 0.28 to 0.64). Overall our model explains 90% of the variation in aggravated assault across the cities examined. In the case of New Orleans, 85% of temporal variation in the aggravated assault rate is explained by the annual rise and fall of air Pb (total=10,179 metric tons) released on the population of New Orleans 22 years earlier. For every metric ton of Pb released 22 years prior, a latent increase of 1.59 (95% CI, 1.36 to 1.83, p<0.001) aggravated assaults per 100,000 were reported. Vehicles consuming fuel containing Pb additives contributed much larger quantities of Pb dust than generally recognized. Our findings along with others predict that prevention of children's lead exposure from lead dust now will realize numerous societal benefits two decades into the future, including lower rates of aggravated assault. PMID:22484219

  10. Magnetic signature of indoor air pollution: Household dust study

    NASA Astrophysics Data System (ADS)

    Górka-Kostrubiec, Beata; Jeleńska, Maria; Król, Elżbieta

    2014-12-01

    The combination of magnetic and geochemical methods was used to determine the mineralogy, grain size and domain structure of magnetic particles in indoor dust collected in 195 sites in Warsaw, Poland. Data show an asymmetric distribution of magnetic susceptibility (χ) in the wide range of 20-1514 × 10-8 m3 kg-1. Comparison of magnetic parameters shows that the internal dust contains outside pollution characteristic for air and soil. More than 90% of indoor dust samples were characterized by roughly uniform magnetic mineralogy, typical for fine grained magnetite (diameter of 0.2-5 μm), and grain size between pseudo-single-domain and small multi-domain with small contribution of superpara-magnetic particles (˜10%). Samples with χ larger than 220 × 10-8 m3 kg-1 contain mainly magnetite and an anthropogenic metallic Fe with T C > 700°C. The indoor dust contains, characteristic for the urban areas, spherical magnetic particles originated from fossil fuel combustion processes and mixture of irregular angular iron-oxides grains containing other elements, including Na, Ca, Al, Si, K, S, Mn, Cl, and Mg.

  11. 40 CFR 81.85 - Metropolitan Sioux Falls Interstate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Metropolitan Sioux Falls Interstate Air Quality Control Region. 81.85 Section 81.85 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions §...

  12. Mycoflora of air-conditioners dust from Riyadh, Saudi Arabia.

    PubMed

    Bagy, M M; Gohar, Y M

    1988-01-01

    Using the hair baiting technique, 6 genera and 14 species were collected on Sabouraud's dextrose agar from 37 dust samples from air-conditioners. The most common fungi were Chrysosporium tropicum, C. indicum, C. keratinophilum, Aspergillus flavus followed by Acremonium strictum and Scopulariopsis brevicaulis. Using the dilution-plate method, 26 genera and 52 species were collected from 37 dust samples on glucose-(23 genera and 45 species) and cellulose-(18 genera and 34 species) Czapek's agar at 28 degrees C. The most prevalent species were Aspergillus niger, A. flavus, Penicillium chrysogenum, Stachybotrys chartarum, Ulocladium atrum, Mucor racemosus and Fusarium solani and A. niger, A. flavus, Trichoderma viride, P. chrysogenum, Ulocladium atrum, Chaetomium globosum, C. spirale, Stachybotrys chartarum and Mucor racemosus on the two media, respectively. PMID:3236219

  13. Air density measurement with a falling A4 sheet

    NASA Astrophysics Data System (ADS)

    Oladyshkin, Ivan V.; Oladyshkina, Anastasia A.

    2016-09-01

    We propose a simple experiment on the air density measurement which does not require any special equipment: just an A4 sheet of paper, a stopwatch and a ruler. The discussed method uses the most basic air resistance model.

  14. AIRS Detection of Dust: Global Map for July 2003

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The averaged brightness temperature differences between the 961 and 1231 cm-1 AIRS channels for July 2003, reveal long range transport of Sahara Dust across the Atlantic.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  15. 40 CFR 81.85 - Metropolitan Sioux Falls Interstate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Region. The Metropolitan Sioux Falls Interstate Air Quality Control Region (Iowa-South Dakota) has been... delimited): In the State of Iowa: Lyon County. In the State of South Dakota: Lincoln County, McCook...

  16. 40 CFR 81.85 - Metropolitan Sioux Falls Interstate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Region. The Metropolitan Sioux Falls Interstate Air Quality Control Region (Iowa-South Dakota) has been... delimited): In the State of Iowa: Lyon County. In the State of South Dakota: Lincoln County, McCook...

  17. 40 CFR 81.85 - Metropolitan Sioux Falls Interstate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Region. The Metropolitan Sioux Falls Interstate Air Quality Control Region (Iowa-South Dakota) has been... delimited): In the State of Iowa: Lyon County. In the State of South Dakota: Lincoln County, McCook...

  18. 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

  19. Clearing the Martian air - The troubled history of dust storms

    NASA Astrophysics Data System (ADS)

    Martin, L. J.

    1984-03-01

    This note is an attempt to resolve some misconceptions regarding the historical record of the Martian atmospheric phenomena referred to as 'dust storms,' but often called yellow storms, yellow clouds, planetwide dust storms, global dust storms, great dust storms, etc. The known frequency of planet-encircling storms will be specifically addressed. Better knowledge of the sizes, frequencies, and locations of Martian dust storms is needed for atmospheric modeling and for future mission planning.

  20. MEASUREMENT OF AIR ENTRAINMENT AND DUST EMISSION DURING SHELLED CORN RECEIVING OPERATIONS WITH SIMULATED HOPPER BOTTOM GRAIN TRAILERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dust emissions from grain elevator operations can be a safety and health risk, and a nuisance. Dust emission and air entrainment data are needed for designing adequate and effective control methods. This study measured the dust emitted and air entrained during corn receiving operations at an eleva...

  1. Episode simulation of Asian dust storms with an air quality modeling system

    NASA Astrophysics Data System (ADS)

    Ge, Cui; Zhang, Meigen; Han, Zhiwei; Liu, Yanju

    2011-05-01

    A dust deflation module was developed and coupled with the air quality modeling system RAMS-CMAQ to simultaneously treat all the major tropospheric aerosols (i.e., organic and black carbons, sulfate, nitrate, ammonia, soil dust, and sea salt). Then the coupled system was applied to East Asia to simulate Asian dust aerosol generation, transport and dry/wet removal processes during 14-25 March 2002 when two strong dust storms occurred consecutively. To evaluate model performance and to analyze the observed features of dust aerosols over the East Asian region, model results were compared to concentrations of suspended particulate matter of 10 µm or less (PM10; 1-h intervals) at four remote Japanese stations and daily air pollution index (API) values for PM10 at four large Chinese cities. The modeled values were generally in good agreement with observed data, and the model reasonably reproduced two dust storm outbreaks and generally predicted the dust onset and cessation times at each observation site. In addition, hourly averaged values of aerosol optical thickness (AOT) were calculated and compared with observations at four Aerosol Robotic Network (AERONET) stations to assess the model's capability of estimating dust aerosol column burden. Analysis shows that modeled and observed AOT values were generally comparable and that the contribution of dust aerosols to AOT was significant only with regard to their source regions and their transport paths.

  2. Soluble iron dust export in the high altitude Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Ravelo-Pérez, L. M.; Rodríguez, S.; Galindo, L.; García, M. I.; Alastuey, A.; López-Solano, J.

    2016-05-01

    Every summer huge amounts of desert dust particles are exported from the hyperarid subtropical Sahara to the North Atlantic the so-called Saharan Air Layer (SAL), a dry, warm and dust-laden corridor that expands from the North African coast (1-5 km.a.s.l.) to the Americas above the marine boundary layer. Because of the potential impact of the dust deposited on the ocean on marine biogeochemistry and climate, we studied the Fe solubility (in seawater) of atmospheric aerosols samples directly collected in the SAL off the North African coast, i.e. the fresh aerosols recently exported from the Sahara in the SAL. The aerosol sampling was performed at ∼2400 m.a.s.l. in Izaña observatory in Tenerife island. In the total aerosols, we found low Fe concentrations and high fractional Fe solubility (FFS ∼2%) in the North Atlantic free troposphere airflows and high Fe concentrations and low FFS (∼0.7%) within the SAL; the resulting FFS versus total dust (or total Fe) plot shows a hyperbolic trend attributed to the conservative mixing of 'fine combustion aerosols' and 'lithogenic mineral dust'. We then focused on the soluble Fe in the SAL. Our results indicate that ∼70% of soluble Fe is associated with the dissolution of submicron dust particles, probably involving Fe-bearing clays. We found a FFS of submicron dust (∼6%) higher than that typically observed in submicron particles of soil dust samples (<1%). The correlation between FFS and the ammonium-sulphate/dust ratio and the low variability in the Fe/Al ratio in the dust samples, suggests that the increase in the FFS of submicron dust aerosols (with respect to soil dust particles) may be related to the presence of acid pollutants mixed with dust. Previous studies had focused on dust processing and changes of Fe solubility during the trans-Atlantic transport of dust in the SAL. We found that submicron dust exported off the coast of North Africa may have already experienced acid processing over the Sahara, i

  3. Impact of Asian Dust on Global Surface Air Quality and Radiation Budget

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Yu, Hongbin; Ginoux, Paul

    2006-01-01

    Dust originating from Asian deserts and desertification areas can be transported regionally and globally to affect surface air quality, visibility, and radiation budget not only at immediate downwind locations (e.g., eastern Asia) but also regions far away from the sources (e.g., North America). Deposition of Asian dust to the North Pacific Ocean basin influences the ocean productivity. In this study, we will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, remote sensing data form satellite and from the ground-based network, and in-situ data from aircraft and surface observations to address the following questions: - What are the effects of Asian dust on the surface air quality and visibility over Asia and North America? - What are the seasonal and spatial variations of dust deposition to the North Pacific Ocean? How does the Asian dust affect surface radiation budget?

  4. Adapting MODIS Dust Mask Algorithm to Suomi NPP VIIRS for Air Quality Applications

    NASA Astrophysics Data System (ADS)

    Ciren, P.; Liu, H.; Kondragunta, S.; Laszlo, I.

    2012-12-01

    algorithm flags pixels that fall into the glint region so sun glint is not picked up as dust. The algorithm also has a spatial variability test that uses reflectances at 0.86 μm to screen for clouds over water. Analysis of one granule for a known dust event on May 2, 2012 shows that the agreement between VIIRS and MODIS is 82% and VIIRS and CALIPSO is 71%. The probability of detection for VIIRS when compared to MODIS and CALIPSO is 53% and 45% respectively whereas the false alarm ratio for VIIRS when compared to MODIS and CALIPSO is 20% and 37% respectively. The algorithm details, results from the test cases, and the use of the dust flag product in NWS applications will be presented.

  5. Rationing health protection: a proposal to exempt nuisance dust from US Clean Air Act regulations.

    PubMed

    Centner, Terence J; Colson, Gregory

    2013-03-15

    The US House of Representative has passed a bill called the "Farm Dust Regulation Prevention Act" (Dust Act) that would exempt most types of particulate matter (PM) in rural areas from the air quality controls of the US Clean Air Act. The Dust Act would markedly change the country's air quality standards. An examination of the proposed provisions shows that they would exempt non-combustion PM pollutants from mining, smelting, petroleum production, and power generation from existing air quality standards. Persons downwind from pollutants generated in rural areas could be exposed to concentrations of carcinogenic heavy metals, asbestos, and benzene known to adversely affect their health and ecological resources. Existing federal air quality standards based on science would be replaced by a flexible standard that rations health protection. PMID:23376304

  6. Ice Nucleating Particle Properties in the Saharan Air Layer Close to the Dust Source

    NASA Astrophysics Data System (ADS)

    Boose, Y.; Garcia, I. M.; Rodríguez, S.; Linke, C.; Schnaiter, M.; Nickovic, S.; Lohmann, U.; Kanji, Z. A.; Sierau, B.

    2015-12-01

    In August 2013 and 2014 measurements of ice nucleating particle (INP) concentrations, aerosol particle size distributions, chemistry and fluorescence were conducted at the Izaña Atmospheric Observatory located at 2373 m asl on Tenerife, west off the African shore. During summer, the observatory is frequently within the Saharan Air Layer and thus often exposed to dust. Absolute INP concentrations and activated fractions at T=-40 to -15°C and RHi=100-150 % were measured. In this study, we discuss the in-situ measured INP properties with respect to changes in the chemical composition, the biological content, the source regions as well as transport pathways and thus aging processes of the dust aerosol. For the first time, ice crystal residues were also analyzed with regard to biological content by means of their autofluorescence signal close to a major dust source region. Airborne dust samples were collected with a cyclone for additional offline analysis in the laboratory under similar conditions as in the field. Both, in-situ and offline dust samples were chemically characterized using single-particle mass spectrometry. The DREAM8 dust model extended with dust mineral fractions was run to simulate meteorological and dust aerosol conditions for ice nucleation. Results show that the background aerosol at Izaña was dominated by carbonaceous particles, which were hardly ice-active under the investigated conditions. When Saharan dust was present, INP concentrations increased by up to two orders of magnitude even at water subsaturated conditions at T≤-25°C. Differences in the ice-activated fraction were found between different dust periods which seem to be linked to variations in the aerosol chemical composition (dust mixed with changing fractions of sea salt and differences in the dust aerosol itself). Furthermore, two biomass burning events in 2014 were identified which led to very low INP concentrations under the investigated temperature and relative humidity

  7. Origin of reverse-graded bedding in air-fall pumice, Coso Range, California

    USGS Publications Warehouse

    Duffield, W.A.; Bacon, C.R.; Roquemore, G.R.

    1979-01-01

    The origin of reverse grading in air-fall pyroclastic deposits has been ascribed to: (1) changing conditions at an erupting vent; (2) deposition in water; or (3) rolling of large clasts over smaller clasts on the surface of a steep slope. Structural features in a deposit of air-fall pumice lapilli in the Coso Range, California, indicate that reverse grading there formed by a fourth mechanism during flow of pumice. Reverse-graded beds in this deposit occur where pumice lapilli fell on slopes at or near the angle of repose and formed as parts of the blanket of accumulating pumice became unstable and flowed downslope. The process of size sorting during such flow is probably analogous to that which sorts sand grains in a reverse fashion during avalanching on the slip faces of sand dunes, attributed by Bagnold (1954a) to a grain-dispersive pressure acting on particles subjected to a shear stress. In view of the several ways in which air-fall pyroclastic debris may become reverse graded, caution is advised in interpretation of the origin of this structure both in modern and in ancient deposits. ?? 1979.

  8. Aerosol Absorption by Black Carbon and Dust: Implications of Climate Change and Air Quality in Asia

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2010-01-01

    Atmospheric aerosol distributions from 2000 to 2007 are simulated with the global model GOCART to attribute light absorption by aerosol to its composition and sources. We show the seasonal and interannual variations of absorbing aerosols in the atmosphere over Asia, mainly black carbon and dust. and their linkage to the changes of anthropogenic and dust emissions in the region. We compare our results with observations from satellite and ground-based networks, and estimate the importance of black carbon and dust on regional climate forcing and air quality.

  9. Fall 1994 wildlife and vegetation survey, Norton Air Force Base, California

    SciTech Connect

    Not Available

    1994-12-15

    The fall 1994 wildlife and vegetation surveys were completed October 3-7, 1994, at Norton Air Force Base (AFB), California. Two biologists from CDM Federal Programs, the U.S. Environmental Protection Agency (EPA) regional biologist and the Oak Ridge National Laboratory (ORNL) lead biologist conducted the surveys. A habitat assessment of three Installation Restoration Project (IRP) sites at Norton Air Force Base was also completed during the fall survey period. The IRP sites include: Landfill No. 2 (Site 2); the Industrial Wastewater Treatment Plant (IWTP) area; and Former Fire Training Area No. 1 (Site 5). The assessments were designed to qualitatively characterize the sites of concern, identify potential ecological receptors, and provide information for Remedial Design/Remedial Action activities. A Reference Area (Santa Ana River Wash) and the base urban areas were also characterized. The reference area assessment was performed to provide a baseline for comparison with the IRP site habitats. The fall 1994 survey is the second of up to four surveys that may be completed. In order to develop a complete understanding of all plant and animal species using the base, these surveys were planned to be conducted over four seasons. Species composition can vary widely during the course of a year in Southern California, and therefore, seasonal surveys will provide the most complete and reliable data to address changes in habitat structure and wildlife use of the site. Subsequent surveys will focus on seasonal wildlife observations and a spring vegetation survey.

  10. A Photographic Study of Freezing of Water Droplets Falling Freely in Air

    NASA Technical Reports Server (NTRS)

    Dorsch, Robert G.; Levine, Joseph

    1952-01-01

    A photographic technique for investigating water droplets of diameter less than 200 microns falling freely in air at temperatures between 0 C and -50 C has been devised and used to determine: (i) The shape of frozen droplets (2) The occurrence of collisions of partly frozen or of frozen and liquid droplets (3) The statistics on the freezing temperatures of individual free-falling droplets A considerable number of droplets were found to have a nonspherical shape after freezing because of various protuberances and frost growth, and droplet aggregates formed by collision. The observed frequency of collision of partly frozen droplets showed good order of magnitude agreement with the frequency computed from theoretical collection efficiencies. The freezing temperature statistics indicated a general similarity of the data to those obtained for droplets frozen on a metallic surface in previous experiments.

  11. Spectronephelometric methods to determine microphysical characteristics of dust in aspiration air and off-gases in cement plants

    NASA Astrophysics Data System (ADS)

    Lisenko, S. A.; Kugeiko, M. M.

    2012-03-01

    The information value of spectral directional scattering coefficients of cement dust released into both the atmosphere and aspiration air during cement production is analyzed in terms of the concentration and effective dust particle size based on a regression approach to solving the inverse problem. The most effective layouts of dust meters that combine ease of implementation with high accuracy over the entire range of physicochemical properties of dust are considered.

  12. Concentration and determinants of molds and allergens in indoor air and house dust of French dwellings.

    PubMed

    Dallongeville, Arnaud; Le Cann, Pierre; Zmirou-Navier, Denis; Chevrier, Cécile; Costet, Nathalie; Annesi-Maesano, Isabella; Blanchard, Olivier

    2015-12-01

    Molds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factors. PMID:26094801

  13. RADIOLOGICAL RELEASES DUE TO AIR AND SILICA DUST ACTIVATION IN EMPLACEMENT DRIFTS

    SciTech Connect

    J.S. Tang

    2003-05-07

    The purpose of this calculation is to determine the quantity and significance of annual Monitored Geologic Repository (MGR) subsurface normal radiological releases due to neutron activation of air and silica dust in emplacement drifts. This calculation includes the following items: (1) Calculate activation of ventilation airflow through emplacement drifts to quantify radioactive gaseous releases; and (2) Calculate the bounding potential activated silica dust concentration and releases. The sources of silica dust may arise from air supply to emplacement drifts as well as host rock around emplacement drifts. For this calculation, the source of dust is conservatively assumed to be the host rock (Assumption 3.6), which is subject to long-term neutron exposure resulting in saturated radioactivity. The scope of this calculation is limited to releases from activated air and silica dust only, excluding natural radioactive releases such as radon or releases from defective waste packages (breached or contaminated). This work supports the repository ventilation system design and Preclosure Safety Analysis. This includes MGR items classified as Quality Level 1, for example, the Uncanistered Spent Nuclear Fuel Waste Package (CRWMS M&O [Civilian Radioactive Waste Management and Operation Contractor] 1999a, page 7). Therefore, this calculation is subject to the requirements of the ''Quality Assurance Requirements and Description'' (DOE [U.S. Department of Energy] 2003). The performance of the calculation and development of this document are carried out in accordance with AP-3.12Q, ''Design Calculation and Analyses'' and LP-3.30Q-BSC, ''Hazards Analysis System''.

  14. 42 CFR 84.1143 - Dust, fume, and mist air-purifying filter tests; performance requirements; general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Dust, fume, and mist air-purifying filter tests; performance requirements; general. 84.1143 Section 84.1143 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... Efficiency Respirators and Combination Gas Masks § 84.1143 Dust, fume, and mist air-purifying filter...

  15. 42 CFR 84.1143 - Dust, fume, and mist air-purifying filter tests; performance requirements; general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Dust, fume, and mist air-purifying filter tests; performance requirements; general. 84.1143 Section 84.1143 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... Efficiency Respirators and Combination Gas Masks § 84.1143 Dust, fume, and mist air-purifying filter...

  16. 42 CFR 84.1143 - Dust, fume, and mist air-purifying filter tests; performance requirements; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Dust, fume, and mist air-purifying filter tests; performance requirements; general. 84.1143 Section 84.1143 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... Efficiency Respirators and Combination Gas Masks § 84.1143 Dust, fume, and mist air-purifying filter...

  17. 42 CFR 84.1143 - Dust, fume, and mist air-purifying filter tests; performance requirements; general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Dust, fume, and mist air-purifying filter tests; performance requirements; general. 84.1143 Section 84.1143 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... Efficiency Respirators and Combination Gas Masks § 84.1143 Dust, fume, and mist air-purifying filter...

  18. 42 CFR 84.1143 - Dust, fume, and mist air-purifying filter tests; performance requirements; general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Dust, fume, and mist air-purifying filter tests; performance requirements; general. 84.1143 Section 84.1143 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... Efficiency Respirators and Combination Gas Masks § 84.1143 Dust, fume, and mist air-purifying filter...

  19. Synergistic use of AIRS and MODIS for dust top height retrieval over land

    NASA Astrophysics Data System (ADS)

    Yao, Zhigang; Li, Jun; Zhao, Zengliang

    2015-04-01

    It is nontrivial to extract the dust top height (DTH) accurately from passive instruments over land due to the complexity of the surface conditions. The Moderate Resolution Imaging Spectroradiometer (MODIS) deep blue (DB) algorithm can be used to infer the aerosol optical depth (AOD) over high-reflective surfaces. The Atmospheric Infrared Sounder (AIRS) can simultaneously obtain the DTH and optical depth information. This study focuses on the synergistic use of AIRS observations and MODIS DB results for improving the DTH by using a stable relationship between the AIRS infrared and MODIS DB AODs. A one-dimensional variational (1DVAR) algorithm is applied to extract the DTH from AIRS. Simulation experiments indicate that when the uncertainty of the dust optical depth decreases from 50% to 20%, the improvement of the DTH retrieval accuracy from AIRS reaches 200 m for most of the assumed dust conditions. For two cases over the Taklimakan Desert, the results are compared against Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements. The results confirm that the MODIS DB product could help extract the DTH over land from AIRS.

  20. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    PubMed Central

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  1. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    NASA Astrophysics Data System (ADS)

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-07-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface.

  2. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air.

    PubMed

    Hassan, Ghassan; Yilbas, B S; Said, Syed A M; Al-Aqeeli, N; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  3. Chlorinated paraffins in indoor air and dust: concentrations, congener patterns, and human exposure.

    PubMed

    Fridén, Ulrika E; McLachlan, Michael S; Berger, Urs

    2011-10-01

    Chlorinated paraffins (CPs) are large production volume chemicals used in a wide variety of commercial applications. They are ubiquitous in the environment and humans. Human exposure via the indoor environment has, however, been barely investigated. In the present study 44 indoor air and six dust samples from apartments in Stockholm, Sweden, were analyzed for CPs, and indoor air concentrations are reported for the first time. The sumCP concentration (short chain CPs (SCCPs) and medium chain CPs (MCCPs)) in air ranged from <5-210 ng m(-3) as quantified by gas chromatography coupled to electron ionization tandem mass spectrometry (GC/EI-MS/MS). Congener group patterns were studied using GC with electron capture negative ionization MS (GC/ECNI-MS). The air samples were dominated by the more volatile SCCPs compared to MCCPs. SumCPs were quantified by GC/EI-MS/MS in the dust samples at low μg g(-1) levels, with a chromatographic pattern suggesting the prevalence of longer chain CPs compared to air. The median exposure to sumCPs via the indoor environment was estimated to be ~1 μg day(-1) for both adults and toddlers. Adult exposure was dominated by inhalation, while dust ingestion was suggested to be more important for toddlers. Comparing these results to literature data on dietary intake indicates that human exposure to CPs from the indoor environment is not negligible. PMID:21612825

  4. Douglas Battery Mfg. Co. achieves outstanding air quality, energy savings - with dust collection/recirculating system

    SciTech Connect

    Not Available

    1988-08-01

    Douglas Battery Manufacturing Company of Winston-Salem, NC has engineered a filtration system that not only delivers excellent air quality - it also reduces heating costs in the plant, since the filtered air is recirculated through the work area after it leaves the dust-collection unit. Douglas engineers reviewed several alternatives, including pulse jet baghouses, before selecting a Tenkay aspirated cartridge dust collection from Farr Company, El Segundo, CA. At present, Douglas is operating four Tenkay collectors. The average air to filter surface ratio of a Farr cartridge is 1.5:1. Two of the units handle 21,500 cfm each, the others handle 25,000 cfm each. Testing by U.S. EPA Reference Method 12 confirmed that the unit's emissions are significantly lower than those established by federal New Source Performance Standards.

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

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, R.; Rajkumar, P.

    2013-08-01

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

  6. The Impact of Saharan Air Layer Dust on the Intensity and Intensity Change of Hurricane Earl

    NASA Astrophysics Data System (ADS)

    Bucher, G.; Boybeyi, Z.

    2012-12-01

    The study of tropical cyclone (TC) intensity and intensity change has become an increasingly important research topic, as the storms pose a significant threat to the lives and property along coastal regions, and maritime interests. The Saharan Air Layer (SAL) is an elevated layer of warm, dry, and dusty air that is formed by intense heating and strong winds over the Sahara desert. This dust, and hot and dry air moves across the Atlantic over the maritime layer. An emerging area of research is the role that the SAL has on the development and intensity of TCs in the North Atlantic tropical basin. In 2010, Hurricane Earl gave us a unique opportunity to study the effects of the SAL during the formative stages of the storm. Using the Weather and Forecasting Model with chemistry (WRF-Chem), this study investigated what the effect of SAL characteristics (thermodynamic and aerosol) had on Earl's intensity and intensity change. We concentrated on the direct and indirect radiative effects of the SAL aerosols, by utilizing the dust-only module in WRF-Chem and comparing results to observations, reanalysis, and a dust-free run. The results show that Earl did not appreciably intensify until it moved out from beneath the influence of the SAL, after which it evolved into a CAT 4 hurricane. This was due mainly to the shear associated with the SAL, but the dust radiative effects also contributed to the slow growth.

  7. Street dust: implications for stormwater and air quality, and environmental through street sweeping.

    PubMed

    Calvillo, Steven J; Williams, E Spencer; Brooks, Bryan W

    2015-01-01

    Street dust represents a source of dual potential risk to stormwater and air quality. It has been well documented that street dust washes into local watersheds and can degrade water quality. Research has also demonstrated that ambient particulate matter (PM10) , which is associated with adverse health outcomes, can arise from resuspension of accumulated street dust. Furthermore, many contaminants, including metals, are present at higher concentrations in the smallest available particles, which are more likely to be resuspended in air and stormwater runoff. Although street cleaning is listed as a best management practice for storm water quality by the EPA, data are limited on the critical parameters (technology, environment, usage), which determine the effectiveness of any street cleaning program, particularly in the peer-reviewed literature. The purpose of the present study was to develop a comprehensive understanding of the efficacy of various street cleaning technologies and practices to protect both water quality and public health. Few studies have compared the effectiveness of street sweeping technologies to remove street dust. Unfortunately, the dearth of comprehensive data on exposure, contaminant concentrations, and efficacy of various sweeping technologies and strategies precludes developing quantitative estimates for potential risk to humans and the environment. Based on the few studies available, regenerative air street sweepers appear to provide the most benefit with regard to collection of small particles and prevention of re-entrainment. It is also clear from the available data that local conditions, climate, and specific needs are critical determinants of the ideal street sweeping strategy (technology, frequency, speed, targeted areas, etc.). Given the critical need for protection of water and air quality in rapidly expanding urban regions (e.g., megacities), further research is necessary to develop best practices for street dust management. Herein

  8. Lessons from Popocatepetl Volcano (Mexico): Ancient Settlement Buried by Lavas, Mudflows, and Air-Fall Deposits

    NASA Technical Reports Server (NTRS)

    Delgado, H.; Panfil, M.; Gonzalez, E. A.; Coyoacan, C. U.; Urangaela, G.; Plunket, P.; Gardner, T.; Abrams, M.

    1994-01-01

    Popocatepetl volcano is 5452 m in altitude and capped by glaciers with a long Late Pleistocene-Holocene history. Volcanic activity has been intense during the last 10 000 years. Therefore, the valleys at the NE foothills of the volcano, covered by air-fall ejecta and drained by the runoff of the glaciers, became very attractive to ancient inhabitants of the Xalizintla Valley (XV) west of Puebla City, because of fertility of soils. The XV was occupied by humans about 2000 years ago who witnessed five events related to volcanic activity related to Popo. These events, described in this paper, are being taken into account for volcanic risk evaluation since several towns with a population of more than 23 000 people reoccupied again the Xalizintla Valley.

  9. Spain as an emergency air traffic hub during volcanic air fall events? Evidence of past volcanic ash air fall over Europe during the late Pleistocene

    NASA Astrophysics Data System (ADS)

    Hardiman, Mark; Lane, Christine; Blockley, Simon P. E.; Moreno, Ana; Valero-Garcés, Blas; Ortiz, José E.; Torres, Trino; Lowe, John J.; Menzies, Martin A.

    2010-05-01

    Past volcanic eruptions often leave visible ash layers in the geological record, for example in marine or lake sedimentary sequences. Recent developments, however, have shown that non-visible volcanic ash layers are also commonly preserved in sedimentary deposits. These augment the record of past volcanic events by demonstrating that past ash dispersals have been more numerous and widely disseminated in Europe than previously appreciated. The dispersal ‘footprints' of some large late Pleistocene European eruptions are examined here in the light of the recent Eyjafjallajökull eruption. For example, the Vedde Ash which was erupted from Iceland around 12 thousand years ago, delivered distal (and non-visible) glass deposits as far south as Switzerland and as far east as the Ural Mountains in Russia, with an overall European distribution remarkably similar to the dominant tracks of the recent Eyjafjallajökull plumes. The Eyjafjallajökull eruption has demonstrated that relatively small amounts of distal volcanic ash in the atmosphere can seriously disrupt aviation activity, with attendant economic and other consequences. It has raised fundamental questions about the likelihood of larger or more prolonged volcanic activity in the near future, and the possibility of even more serious consequences than those experienced recently. Given that there are several other volcanic centres that could cause such disruption in Europe (e.g. Campania and other volcanic centres in Italy; Aegean volcanoes), a key question is whether there are parts of Europe less prone to ash plumes and which could therefore operate as emergency air traffic hubs during times of ash dispersal. Although not generated to answer this question, the recent geological record might provide a basis for seeking the answer. For example, four palaeo-records covering the time frame of 8 - 40 Ka BP that are geographically distributed across Spain have been examined for non-visible distal ash content. All four have

  10. Burning Velocity Measurements in Aluminum-Air Suspensions using Bunsen Type Dust Flames

    NASA Technical Reports Server (NTRS)

    Lee, John; Goroshin, Samuel; Kolbe, Massimiliano

    2001-01-01

    Laminar burning velocity (sometimes also referred in literature as fundamental or normal flame propagation speed) is probably the most important combustion characteristic of the premixed combustible mixture. The majority of experimental data on burning velocities in gaseous mixtures was obtained with the help of the Bunsen conical flame. The Bunsen cone method was found to be sufficiently accurate for gaseous mixtures with burning velocities higher than 10-15 cm/s at normal pressure. Hans Cassel was the first to demonstrate that suspensions of micron-size solid fuel particles in a gaseous oxidizer can also form self-sustained Bunsen flames. He was able to stabilize Bunsen flames in a number of suspensions of different nonvolatile solid fuels (aluminum, carbon, and boron). Using the Bunsen cone method he estimated burning velocities in the premixed aluminum-air mixtures (particle size less than 10 microns) to be in the range of 30-40 cm/s. Cassel also found, that the burning velocity in dust clouds is a function of the burner diameter. In our recent work, we have used the Bunsen cone method to investigate dependence of burning velocity on dust concentration in fuel-rich aluminum dust clouds. Burning velocities in stoichiometric and fuel-rich aluminum dust suspensions with average particle sizes of about 5 microns were found to be in the range of 20-25 cm/s and largely independent on dust concentration. These results raise the question to what degree burning velocities derived from Bunsen flame specifically and other dust flame configurations in general, are indeed fundamental characteristics of the mixture and to what degree are they apparatus dependent. Dust flames in comparison to gas combustion, are thicker, may be influenced by radiation heat transfer in the flame front, respond differently to heat losses, and are fundamentally influenced by the particular flow configuration due to the particles inertia. Since characteristic spatial scales of dust flames are

  11. Detailed cloud resolving model simulations of the impacts of Saharan air layer dust on tropical deep convection - Part 1: Dust acts as ice nuclei

    NASA Astrophysics Data System (ADS)

    Gong, W.; Min, Q.; Li, R.; Teller, A.; Joseph, E.; Morris, V.

    2010-05-01

    Observational studies suggest that the Saharan Air Layer (SAL), an elevated layer (850-500 hPa) of Saharan air and mineral dust, has strong impacts on the microphysical as well as dynamical properties of tropical deep convective cloud systems along its track. In this case study, numerical simulations using a two-dimensional Detailed Cloud Resolving Model (DCRM) were carried out to investigate the dust-cloud interactions in the tropical deep convection, focusing on the dust role as Ice Nuclei (IN). The simulations showed that mineral dust considerably enhanced heterogeneous nucleation and freezing at temperatures warmer than -40 °C, resulting in more ice hydrometeors number concentration and reduced precipitating size of ice particles. Because of the lower in the saturation over ice as well as more droplet freezing, total latent heating increased, and consequently the updraft velocity was stronger. On the other hand, the increased ice deposition consumed more water vapor at middle troposphere, which induces a competition for water vapor between heterogeneous and homogeneous freezing and nucleation. As a result, dust suppressed the homogeneous droplet freezing and nucleation due to the heterogeneous droplet freezing and the weakened transport of water vapor at lower stratosphere, respectively. These effects led to decreased number concentration of ice cloud particles in the upper troposphere, and consequently lowered the cloud top height during the stratus precipitating stage. Acting as IN, mineral dust also influenced precipitation in deep convection. It initiated earlier the collection because dust-related heterogeneous nucleation and freezing at middle troposphere occur earlier than homogeneous nucleation at higher altitudes. Nevertheless, the convective precipitation was suppressed by reduced collection of large graupel particles and insufficient fallout related to decreased sizes of precipitating ice hydrometeors. On the contrary, dust increased the

  12. Comparison of characteristics of aerosol during rainy weather and cold air-dust weather in Guangzhou in late March 2012

    NASA Astrophysics Data System (ADS)

    Chen, Huizhong; Wu, Dui; Yu, Jianzhen

    2016-04-01

    Using the data on aerosol observed hourly by Marga ADI 2080 and Grimm 180, we compared the characteristics of aerosol during rainy weather and cold air-dust weather in Guangzhou in late March 2012. The mass concentration of aerosol appeared distinct between the two weather processes. During rainy weather, the mass concentration of PM and total water-soluble components decreased obviously. During cold air-dust weather, the cleaning effect of cold air occurred much more suddenly and about a half day earlier than the dust effect. As a result, the mass concentration of PM and total water-soluble components first dropped dramatically to a below-normal level and then rose gradually to an above-normal level. The ratio of PM2.5/PM10 and PM1/PM10 decreased, suggesting that dust-storm weather mainly brought in coarse particles. The proportion of Ca2+ in the total water-soluble components significantly increased to as high as 50 % because of the effect of dust weather. We further analysed the ionic equilibrium during rainy and cold air-dust weather, and compared it with that during hazy weather during the same period. The aerosol during rainy weather was slightly acidic, whereas that during hazy weather and cold air-dust weather was obviously alkaline, with that during cold air-dust weather being significantly more alkaline. Most of the anions, including SO4 2- and NO3 -, were neutralised by NH4 + during rainy and hazy weather, and by Ca2+ during cold air-dust weather.

  13. Field-testing a new directional passive air sampler for fugitive dust in a complex industrial source environment.

    PubMed

    Ferranti, E J S; Fryer, M; Sweetman, A J; Garcia, M A Solera; Timmis, R J

    2014-01-01

    Quantifying the sources of fugitive dusts on complex industrial sites is essential for regulation and effective dust management. This study applied two recently-patented Directional Passive Air Samplers (DPAS) to measure the fugitive dust contribution from a Metal Recovery Plant (MRP) located on the periphery of a major steelworks site. The DPAS can collect separate samples for winds from different directions (12 × 30° sectors), and the collected dust may be quantified using several different measurement methods. The DPASs were located up and down-prevailing-wind of the MRP processing area to (i) identify and measure the contribution made by the MRP processing operation; (ii) monitor this contribution during the processing of a particularly dusty material; and (iii) detect any changes to this contribution following new dust-control measures. Sampling took place over a 12-month period and the amount of dust was quantified using photographic, magnetic and mass-loading measurement methods. The DPASs are able to effectively resolve the incoming dust signal from the wider steelworks complex, and also different sources of fugitive dust from the MRP processing area. There was no confirmable increase in the dust contribution from the MRP during the processing of a particularly dusty material, but dust levels significantly reduced following the introduction of new dust-control measures. This research was undertaken in a regulatory context, and the results provide a unique evidence-base for current and future operational or regulatory decisions. PMID:24296778

  14. Fluidized bed heat exchanger with water cooled air distributor and dust hopper

    DOEpatents

    Jukkola, Walfred W.; Leon, Albert M.; Van Dyk, Jr., Garritt C.; McCoy, Daniel E.; Fisher, Barry L.; Saiers, Timothy L.; Karstetter, Marlin E.

    1981-11-24

    A fluidized bed heat exchanger is provided in which air is passed through a bed of particulate material containing fuel. A steam-water natural circulation system is provided for heat exchange and the housing of the heat exchanger has a water-wall type construction. Vertical in-bed heat exchange tubes are provided and the air distributor is water-cooled. A water-cooled dust hopper is provided in the housing to collect particulates from the combustion gases and separate the combustion zone from a volume within said housing in which convection heat exchange tubes are provided to extract heat from the exiting combustion gases.

  15. Transport of desert dust mixed with North African industrial pollutants in the subtropical Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Rodríguez, S.; Alastuey, A.; Alonso-Pérez, S.; Querol, X.; Cuevas, E.; Abreu-Afonso, J.; Viana, M.; Pérez, N.; Pandolfi, M.; de La Rosa, J.

    2011-07-01

    An analysis of chemical composition data of particulate matter samples (TSP, PM10 and PM2.5) collected from 2002 to 2008 in the North Atlantic free troposphere at the Izaña Global Atmospheric Watch (GAW) observatory (Tenerife, Canary Islands) shows that desert dust is very frequently mixed with particulate pollutants in the Saharan Air Layer (SAL). The study of this data set with Median Concentrations At Receptor (MCAR) plots allowed the identification of the potential source regions of the dust and particulate pollutants. Areas located at the south of the southern slope of the Atlas mountains emerge as the most frequent source of the soil desert dust advected to the northern edge of the SAL in summer. Industrial emissions occurring in Northern Algeria, Eastern Algeria, Tunisia and the Atlantic coast of Morocco appear as the most important source of the nitrate, ammonium and a fraction of sulphate (at least 60 % of the sulphate <10 μm transported from some regions) observed in the SAL. These emissions are mostly linked to crude oil refineries, phosphate-based fertilizer industry and power plants. Although desert dust emissions appear as the most frequent source of the phosphorous observed in the SAL, high P concentrations are observed when the SAL is affected by emissions from open mines of phosphate and phosphate based fertilizer industry. The results also show that a significant fraction of the sulphate (up to 90 % of sulphate <10 μm transported from some regions) observed in the SAL may be influenced by soil emissions of evaporite minerals in well defined regions where dry saline lakes (chotts) are present. These interpretations of the MCAR plots are consistent with the results obtained with the Positive Matrix Factorization (PMF2) receptor modelling. The results of this study show that North African industrial pollutants may be mixed with desert dust and exported to the North Atlantic in the Saharan Air Layer.

  16. Transport of desert dust mixed with North African industrial pollutants in the subtropical Saharan Air Layer

    NASA Astrophysics Data System (ADS)

    Rodríguez, S.; Alastuey, A.; Alonso-Pérez, S.; Querol, X.; Cuevas, E.; Abreu-Afonso, J.; Viana, M.; Pandolfi, M.; de La Rosa, J.

    2011-03-01

    The chemical composition of particulate matter samples (TSP, PM10 and PM2.5) collected from 2002 to 2008 in the North Atlantic free troposphere at Izaña Global Atmospheric Watch (GAW) observatory (Tenerife, The Canary Islands) was studied. The analysis of the samples collected in the Saharan Air Layer (SAL) shows that soil desert dust is very frequently mixed with particulate pollutants. An analysis of this data set with Median Concentrations At Receptor (MCAR) plots allowed to identify the potential source regions of the dust and particulate pollutants. Areas located at the south of the Southern slope of Atlas emerge as the most frequent source of the soil desert dust advected to the northern edge of the SAL in summer. Industrial emissions occurring along the Atlantic coast of Morocco, Northern Algeria, Eastern Algeria and Tunisia appear as the most important source of the nitrate, ammonium and a fraction of sulphate (at least a 60% of the sulphate <10 μm transported from some regions) observed in the SAL. These emissions are mostly linked to crude oil refineries, phosphate-based fertilizer industry and power plants. Although desert dust emissions appear as the most frequent source of the phosphorous observed in the SAL, high P concentrations are observed when the SAL is affected by emissions from open mines of phosphate and phosphate based fertilizer industry. The results also show that a significant fraction of the sulphate (up to 90% of sulphate <10 μm transported from some regions) observed in the SAL is linked to soil emissions of evaporite minerals in well defined regions where dry saline lakes (chotts) are present. These interpretations of the MCAR plots are consistent with the results obtained with the Positive Matrix Factorization receptor modelling. The results of this study show that North African industrial pollutants may be mixed with desert dust and exported to the North Atlantic in the Saharan Air Layer.

  17. Effects of South Asian dust storm on air quality over the capital city of India

    NASA Astrophysics Data System (ADS)

    Yarragunta, Y.; Srivastava, S.

    2016-05-01

    In the present study, an intense unseasonal dust storm has been analyzed during third week of March 2012 from multi satellite datasets and from surface measurements over National Capital Region (NCR), Delhi. The intrusion of dust over study region has increased the MODIS Aerosol Optical Depth at 550 nm more than 1.0 whereas significant decrease in Angstrom Exponent (α) has been observed . Very high UV aerosol Index (> 2) over study location indicates the presence of UV absorbing aerosols . Fire activities are found to be negligible over the source region confirming the effect of dust storm. Strong southwesterly winds prevailed over northern Arabian Sea which trans ported the dust plume across the oceanic region towards Indian capital region. In-situ measurements of PM 2.5 and PM10, obtained from CPCB observational site over the IGI airport, NCR Delhi, showed abrupt increase on 20, 21 March. Eight hourly average concentration of the particulate matters less than 10 μm (PM10) is found to be ~990 μg/m3 and particulate matters less than 2.5 μm (PM2.5) is found to be ~900 μg/m3 over IGI Airport, NCR Delhi. These values are remarkably higher as compared to the daily National Ambient Air Quality Standards (NAAQS) i.e. 100 μg/m3 and 60 μg/m3 for PM10 and PM2.5 respectively. In addition, Vertical distribution of dust has been examined using CALIPSO observation. The layer of dust is found to be trapped within lower 3 km in altitude. The Potential Source Contribution Function (PSCF) modeling has been carried out to identify the specific source locations.

  18. Source apportionment of arsenic in atmospheric dust fall out in an urban residential area, Raipur, Central India

    NASA Astrophysics Data System (ADS)

    Balakrishna, G.; Pervez, S.; Bisht, D. S.

    2011-06-01

    The components and quantities of atmospheric dust fallout have been reported to be the pollution indicator of large urban areas. The multiplicity and complexity of sources of atmospheric dusts in urban regions has put forward the need of source apportionment of these sources indicating their contribution to specific environmental receptor. The study presented here is focused on investigation of source contribution estimates of Arsenic in urban dust fallout in an urban-industrial area, Raipur, India. Source-receptor based representative sampling plan using longitudinal study design has been adopted. Six sampling sites have been identified on the basis of land use for development plan of anthropogenic activities and factors related to the transportation and dispersion pattern of atmospheric dusts. Source apportionment has been done using Chemical Mass Balance (CMB 8). Good fit parameters and relative source contribution has been analyzed and documented. Dominance of coal fired industries sources on arsenic levels measured at selected ambient residential receptors compared to line sources has been observed. Road-traffic has shown highest contribution of dust at indoor houses and out door-street automobile exhaust has shows highest contribution for arsenic. The results of CMB output and regression data of source-receptor dust matrices have shown comparable pattern.

  19. Rapid monitoring of soil, smears, and air dusts by direct large-area alpha spectrometry

    SciTech Connect

    Sill, C.W.

    1992-01-01

    Experimental conditions to permit rapid monitoring of soils, smears, and air dusts for transuranic (TRU) radionuclides under field conditions are described. The monitoring technique involves direct measurement of alpha emitters by alpha spectrometry using a large-area detector to identify and quantify the radionuclides present. The direct alpha spectrometry employs a circular gridded ionization chamber 35 cm in diameter which accommodates either a circular sample holder 25 cm in diameter or a rectangular one 20 by 25 cm (8 by 10 in.). Soils or settled dusts are finely ground, suspended in 30% ethanol, and sprayed onto a 25-cm stainless steel dish. Air dusts are collected with a high-volume sampler onto 20- by 25-cm membrane filters. Removable contamination is collected from surfaces onto a 20- by 25-cm filter using an 18-cm (7-in.) paint roller to hold the large filter in contact with the surface during sample collection. All three types of samples are then counted directly in the alpha spectrometer and no other sample preparation is necessary. Some results obtained are described.

  20. the nature of air flow near the inlets of blunt dust sampling probes

    NASA Astrophysics Data System (ADS)

    Vincent, J. H.; Hutson, D.; Mark, D.

    This paper sets out to describe the nature of air flow near blunt dust samplers in a way which allows a relatively simple assessment of their performances for collecting dust particles. Of particular importance is the shape of the limiting stream surface which divides the sampled air from that which passes outside the sampler, and how this is affected by the free-stream air velocity, the sampling flow rate, and the shape of the sampler body. This was investigated for two-dimensional and axially-symmetric sampler systems by means of complementary experiments using electrolytic tank potential flow analogues and a wind tunnel respectively. For extreme conditions the flow of air entering the sampling orifice may be wholly divergent or wholly convergent. For a wide range of intermediate conditions, however, the flow first diverges then converges, exhibiting a so-called "spring onion effect". Whichever of these applies for a particular situation, the flow may be considered to consist of two parts, the outer one dominated by the flow about the sampler body and the inner one dominated by the flow into the sampling orifice. Particle transport in this two-part flow may be assessed using ideas borrowed from thin-walled probe theory.

  1. Rapid monitoring of soil, water, and air dusts by direct large-area alpha spectrometry.

    PubMed

    Sill, C W

    1995-07-01

    During retrieval and disposition of wastes containing transuranium elements, continuous monitoring of the air, water, and soil for alpha emitters was required to ensure that safety limits were not exceeded and that the waste itself was not disturbed unknowingly. Direct measurements by alpha spectrometry were particularly promising because of their potential speed, sensitivity, and their ability to identify transuranium radionuclides under field conditions. Soil samples or settled dusts were finely ground, suspended in 80% ethanol, sprayed onto circular stainless steel pans, and dried on a hotplate. Water samples were mounted directly by spraying. Air dusts were collected with a high-volume air sampler on 20- by 25-cm membrane filters. The samples were then analyzed directly in a large pressurized gridded ionization chamber without further sample preparation. The lower limits of detection for 10-min counting times were 1.5 Bq g-1 (40 pCi g-1) for 100-mg soil samples, and 4 x 10(-2) Bq m-3 (10(-12) microCi mL-1) for a 10-min air sample taken at 0.4 m3 min-1 (14 cubic feet per minute) and counted without waiting for decay of radon progeny. PMID:7790211

  2. Characteristics of tyre dust in polluted air: Studies by single particle mass spectrometry (ATOFMS)

    NASA Astrophysics Data System (ADS)

    Dall'Osto, Manuel; Beddows, David C. S.; Gietl, Johanna K.; Olatunbosun, Oluremi A.; Yang, Xiaoguang; Harrison, Roy M.

    2014-09-01

    There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35 nm and 85 nm were obtained from SMPS/APS measurements over the range 6-20,000 nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000 nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z > 100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.

  3. Dust in the Earth system: the biogeochemical linking of land, air and sea.

    PubMed

    Ridgwell, Andy J

    2002-12-15

    Understanding the response of the Earth's climate system to anthropogenic perturbation has been a pressing priority for society since the late 1980s. However, recent years have seen a major paradigm shift in how such an understanding can be reached. Climate change demands analysis within an integrated 'Earth-system' framework, taken to encompass the suite of interacting physical, chemical, biological and human processes that, in transporting and transforming materials and energy, jointly determine the conditions for life on the whole planet. This is a highly complex system, characterized by multiple nonlinear responses and thresholds, with linkages often between apparently disparate components. The interconnected nature of the Earth system is wonderfully illustrated by the diverse roles played by atmospheric transport of mineral 'dust', particularly in its capacity as a key pathway for the delivery of nutrients essential to plant growth, not only on land, but perhaps more importantly, in the ocean. Dust therefore biogeochemically links land, air and sea. This paper reviews the biogeochemical role of mineral dust in the Earth system and its interaction with climate, and, in particular, the potential importance of both past and possible future changes in aeolian delivery of the micro-nutrient iron to the ocean. For instance, if, in the future, there was to be a widespread stabilization of soils for the purpose of carbon sequestration on land, a reduction in aeolian iron supply to the open ocean would occur. The resultant weakening of the oceanic carbon sink could potentially offset much of the carbon sequestered on land. In contrast, during glacial times, enhanced dust supply to the ocean could have 'fertilized' the biota and driven atmospheric CO(2) lower. Dust might even play an active role in driving climatic change; since changes in dust supply may affect climate, and changes in climate, in turn, influence dust, a 'feedback loop' is formed. Possible feedback

  4. Dust events in Arizona: Long-term satellite and surface observations, and the National Air Quality Forecasting Capability CMAQ simulations

    NASA Astrophysics Data System (ADS)

    Huang, M.; Tong, D.; Lee, P.; Pan, L.; Tang, Y.; Stajner, I.; Pierce, R. B.; McQueen, J.

    2015-12-01

    Dust events in Arizona: An analysis integrating satellite and surface weather and aerosol measurements, and National Air Quality Forecasting Capability CMAQ simulations Dust records in Arizona during 2005-2013 are developed using multiple observation datasets, including level 2 deep blue aerosol product by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the in-situ measurements at the surface Air Quality System (AQS) and Interagency Monitoring of Protected Visual Environments (IMPROVE) sites in Phoenix. The satellite and surface aerosol observations were anti-correlated with three drought indicators (i.e., MODIS vegetation index, a European satellite soil moisture dataset, and Palmer Drought Severity Index). During the dusty year of 2007, we show that the dust events were stronger and more frequent in the afternoon hours than in the morning due to faster winds and drier soil, and the Sonoran and Chihuahuan deserts were important dust source regions during identified dust events in Phoenix as indicated by NOAA's Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model calculations. Based on these findings, we suggested a potential for use of satellite soil moisture and vegetation index products to interpret and predict dust activity. We also emphasized the importance of using hourly observations for better capturing dust events, and expect the hourly geostationary satellite observations in the future to well complement the current surface PM and meteorological observations considering their broader spatial coverage. Additionally, the performance of the National Air Quality Forecasting Capability (NAQFC) 12 km CMAQ model simulation is evaluated during a recent strong dust event in the western US accompanied by stratospheric ozone intrusion. The current modeling system well captured the temporal variability and the magnitude of aerosol concentrations during this event. Directions of integrating satellite weather and vegetation observations

  5. The Possible Role of air Pollution in Dust-Fe Mobilization and its Implications to Global Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Chameides, W. L.; Meskhidze, N.; Nenes, A.; Luo, C.; Mahowald, N.

    2005-12-01

    For iron (Fe) contained in aeolian dust to act as a micronutrient for oceanic phytoplankton, some fraction of it must first be transformed (mobilized) into a form soluble in ocean water. Dust-Fe solubilization in deliquesced mineral aerosols can occur by the incorporation of SO2 into the advecting dust plumes and subsequent acidification of the dust through heterogeneous SO2 oxidation. The possible role of air pollution in dust-Fe mobilization are investigated in two contrasting studies conducted in: (i) subarctic North Pacific (where long-range advected Gobi-dust plumes travel over industrially developed cities of China and therefore have an ample opportunity to entrain high concentrations of anthropogenic air pollutants, i.e., SO2) and (ii) subantarctic South Atlantic (with dust plumes from Patagonia advected over sparsely populated pristine areas). Both regions of the ocean are known as high-nitrate low-chlorophyll (HNLC) areas where net primary productivity is limited by the availability of iron. In the first study, model simulations are carried out for documented Gobi-desert storms that advected mineral dust to Fe-limited regions of subarctic North Pacific. The estimated change in phytoplankton population inferred from the model-calculated inputs of bioavailable Fe is consistent with the satellite-measured chlorophyll a concentrations, suggesting that air pollution from China may actually affect net primary productivity and the associated uptake of atmospheric carbon dioxide in surface waters North Pacific Ocean. By extension, air pollution controls in China which lowered SO2 emissions might depress carbon uptake in these same waters. Contrasting North Pacific, model simulations for subantarctic South Atlantic suggest that the amount of SO2 available to be mixed with dust plumes from Patagonia is not high enough to acidify mineral dust and solubilize dust-Fe into bioavailable form. Analysis of remotely sensed sea surface temperature, ocean chlorophyll a

  6. Association between Ambient Air Pollution and Emergency Room Visits for Respiratory Diseases in Spring Dust Storm Season in Lanzhou, China

    PubMed Central

    Ma, Yuxia; Xiao, Bingshuang; Liu, Chang; Zhao, Yuxin; Zheng, Xiaodong

    2016-01-01

    Background: Air pollution has become a major global public health problem. A number of studies have confirmed the association between air pollutants and emergency room (ER) visits for respiratory diseases in developed countries and some Asian countries, but little evidence has been seen in Western China. This study aims to concentrate on this region. Methods: A time-series analysis was used to examine the specific effects of major air pollutants (PM10, SO2 and NO2) on ER visits for respiratory diseases from 2007 to 2011 in the severely polluted city of Lanzhou. We examined the effects of air pollutants for stratified groups by age and gender, accounting for the modifying effect of dust storms in spring to test the possible interaction. Results: Significant associations were found between outdoor air pollution concentrations and respiratory diseases, as expressed by daily ER visits in Lanzhou in the spring dust season. The association between air pollution and ER visits appeared to be more evident on dust days than non-dust days. Relative risks (RRs) and 95% CIs per 10 µg/m3 increase in 3-day PM10 (L3), 5-day SO2 (L5), and the average of current and previous 2-day NO2 (L01) were 1.140 (1.071–1.214), 1.080 (0.967–1.205), and 1.298 (1.158–1.454), respectively, on dust days. More significant associations between PM10, SO2 and NO2 and ER visits were found on dust days for elderly females, elderly males and adult males, respectively. Conclusions: This study strengthens the evidence of dust-exacerbated ER visits for respiratory diseases in Lanzhou. PMID:27338430

  7. Effect of atmospheric mixing layer depth variations on urban air quality and daily mortality during Saharan dust outbreaks

    PubMed Central

    Pandolfi, M.; Tobias, A.; Alastuey, A.; Sunyer, J.; Schwartz, J.; Lorente, J.; Pey, J.; Querol, X.

    2016-01-01

    Several epidemiological studies have shown that the outbreaks of Saharan dust over southern European countries can cause negative health effects. The reasons for the increased toxicity of airborne particles during dust storms remain to be understood although the presence of biogenic factors carried by dust particles or the interaction between dust and man-made air pollution have been hypothesized as possible causes. Intriguingly, recent findings have also demonstrated that during Saharan dust outbreaks the local man-made particulates can have stronger effects on health than during days without outbreaks. We show that the thinning of the mixing layer (ML) during Saharan dust outbreaks, systematically described here for the first time, can trigger the observed higher toxicity of ambient local air. The mixing layer height (MLH) progressively reduced with increasing intensity of dust outbreaks thus causing a progressive accumulation of anthropogenic pollutants and favouring the formation of new fine particles or specific relevant species likely from condensation of accumulated gaseous precursors on dust particles surface. Overall, statistically significant associations of MLH with all-cause daily mortality were observed. Moreover, as the MLH reduced, the risk of mortality associated with the same concentration of particulate matter increased due to the observed pollutants accumulation. The association of MLH with daily mortality and the effect of ML thinning on particle toxicity exacerbated when Saharan dust outbreaks occurred suggesting a synergic effect of atmospheric pollutants on health which was amplified during dust outbreaks. Moreover, the results may reflect higher toxicity of primary particles which predominate on low MLH days. PMID:25051327

  8. A comparison of the physical and optical properties of anthropogenic air pollutants and mineral dust over Northwest China

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Pu, Wei; Shi, Jinsen; Bi, Jianrong; Zhou, Tian; Zhang, Xueying; Ren, Yong

    2015-04-01

    Emissions of mineral dust and its mixing with anthropogenic air pollutants affect both regional and global climates. Our fieldwork in late spring 2007 (April 25-June 15) measured the physical and optical properties of dust storms mixed with local air pollutants at a rural site about 48 km southeast of central Lanzhou. Levels of air pollutants and aerosol optical properties were observed during the experiment, with concentrations of NOx (6.8 ± 3.3 ppb, average ± standard deviation), CO (694 ± 486 ppb), SO2 (6.2 ± 10 ppb), O3 (50.7 ± 13.1 ppb), and PM10 (172 ± 180 μg m-3), and aerosol scattering coefficient (164 ± 89 Mm-1; 1 Mm = 106 m) and absorption coefficient (11.7 ± 6.6 Mm-1), all much lower than the values observed during air pollution episodes in urban areas. During a major dust storm, the mass concentration of PM10 reached 4072 μg m-3, approximately 21-fold higher than in non-dust storm periods. The mixing ratios of trace gases declined noticeably after a cold front passed through. The observed CO/SO2 and CO/NOx ratios during air pollution episodes were 4.2-18.3 and 13.7-80.5, respectively, compared with the corresponding ratios of 38.1-255.7 and 18.0-245.9 during non-pollution periods. Our investigations suggest that dust storms have a significant influence on air quality in areas far from their source, and this large-scale transport of dust and air pollutants produces major uncertainties in the quantification of the global effects of emissions over Northwest China.

  9. Atmospheric dust and acid rain

    SciTech Connect

    Hedin, L.O.; Likens, G.E.

    1996-12-01

    Why is acid rain still an environmental problem in Europe and North America despite antipollution reforms? The answer really is blowing in the wind: atmospheric dust. These airborne particles can help neutralize the acids falling on forests, but dust levels are unusually low these days. In the air dust particles can neutralize acid rain. What can we do about acid rain and atmospheric dust? Suggestions range from the improbable to the feasible. One reasonable suggestion is to reduce emissions of acidic pollutants to levels that can be buffered by natural quantities of basic compounds in the atmosphere; such a goal would mean continued reductions in sulfur dioxide and nitrogen oxides, perhaps even greater than those prescribed in the 1990 Amendments to the Clean Air Act in the U.S. 5 figs.

  10. Effects of Large-Scale Solar Installations on Dust Mobilization and Air Quality

    NASA Astrophysics Data System (ADS)

    Pratt, J. T.; Singh, D.; Diffenbaugh, N. S.

    2012-12-01

    Large-scale solar projects are increasingly being developed worldwide and many of these installations are located in arid, desert regions. To examine the effects of these projects on regional dust mobilization and air quality, we analyze aerosol product data from NASA's Multi-angle Imaging Spectroradiometer (MISR) at annual and seasonal time intervals near fifteen photovoltaic and solar thermal stations ranging from 5-200 MW (12-4,942 acres) in size. The stations are distributed over eight different countries and were chosen based on size, location and installation date; most of the installations are large-scale, took place in desert climates and were installed between 2006 and 2010. We also consider air quality measurements of particulate matter between 2.5 and 10 micrometers (PM10) from the Environmental Protection Agency (EPA) monitoring sites near and downwind from the project installations in the U.S. We use monthly wind data from the NOAA's National Center for Atmospheric Prediction (NCEP) Global Reanalysis to select the stations downwind from the installations, and then perform statistical analysis on the data to identify any significant changes in these quantities. We find that fourteen of the fifteen regions have lower aerosol product after the start of the installations as well as all six PM10 monitoring stations showing lower particulate matter measurements after construction commenced. Results fail to show any statistically significant differences in aerosol optical index or PM10 measurements before and after the large-scale solar installations. However, many of the large installations are very recent, and there is insufficient data to fully understand the long-term effects on air quality. More data and higher resolution analysis is necessary to better understand the relationship between large-scale solar, dust and air quality.

  11. Semi-volatile organic compounds in heating, ventilation, and air-conditioning filter dust in retail stores.

    PubMed

    Xu, Y; Liang, Y; Urquidi, J R; Siegel, J A

    2015-02-01

    Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories of semi-volatile organic compounds (SVOCs). Filters in heating, ventilation, and air-conditioning (HVAC) system collect particles from large volumes of air and thus potentially provide spatially and temporally integrated SVOC concentrations. This study measured six phthalate and 14 PBDE compounds in HVAC filter dust in 14 retail stores in Texas and Pennsylvania, United States. Phthalates and PBDEs were widely found in the HVAC filter dust in retail environment, indicating that they are ubiquitous indoor pollutants. The potential co-occurrence of phthalates and PBDEs was not strong, suggesting that their indoor sources are diverse. The levels of phthalates and PBDEs measured in HVAC filter dust are comparable to concentrations found in previous investigations of settled dust in residential buildings. Significant correlations between indoor air and filter dust concentrations were found for diethyl phthalate, di-n-butyl phthalate, and benzyl butyl phthalate. Reasonable agreement between measurements and an equilibrium model to describe SVOC partitioning between dust and gas-phase is achieved. PMID:24766478

  12. Inhalable desert dust, urban emissions, and potentially biotoxic metals in urban Saharan-Sahelian air.

    PubMed

    Garrison, V H; Majewski, M S; Konde, L; Wolf, R E; Otto, R D; Tsuneoka, Y

    2014-12-01

    Saharan dust incursions and particulates emitted from human activities degrade air quality throughout West Africa, especially in the rapidly expanding urban centers in the region. Particulate matter (PM) that can be inhaled is strongly associated with increased incidence of and mortality from cardiovascular and respiratory diseases and cancer. Air samples collected in the capital of a Saharan-Sahelian country (Bamako, Mali) between September 2012 and July 2013 were found to contain inhalable PM concentrations that exceeded World Health Organization (WHO) and US Environmental Protection Agency (USEPA) PM2.5 and PM10 24-h limits 58 - 98% of days and European Union (EU) PM10 24-h limit 98% of days. Mean concentrations were 1.2-to-4.5 fold greater than existing limits. Inhalable PM was enriched in transition metals, known to produce reactive oxygen species and initiate the inflammatory response, and other potentially bioactive and biotoxic metals/metalloids. Eroded mineral dust composed the bulk of inhalable PM, whereas most enriched metals/metalloids were likely emitted from oil combustion, biomass burning, refuse incineration, vehicle traffic, and mining activities. Human exposure to inhalable PM and associated metals/metalloids over 24-h was estimated. The findings indicate that inhalable PM in the Sahara-Sahel region may present a threat to human health, especially in urban areas with greater inhalable PM and transition metal exposure. PMID:25243921

  13. Glaciation temperatures of convective clouds ingesting desert dust, air pollution and smoke from forest fires

    NASA Astrophysics Data System (ADS)

    Rosenfeld, Daniel; Yu, Xing; Liu, Guihua; Xu, Xiaohong; Zhu, Yannian; Yue, Zhiguo; Dai, Jin; Dong, Zipeng; Dong, Yan; Peng, Yan

    2011-11-01

    Heavy aerosol loads have been observed to suppress warm rain by reducing cloud drop size and slowing drop coalescence. The ice forming nuclei (IFN) activity of the same aerosols glaciate the clouds and create ice precipitation instead of the suppressed warm rain. Satellite observations show that desert dust and heavy air pollution over East Asia have similar ability to glaciate the tops of growing convective clouds at glaciation temperature of Tg < ˜ -20°C, whereas similarly heavy smoke from forest fires in Siberia without dust or industrial pollution glaciated clouds at Tg ≤ -33°C. The observation that both smoke and air pollution have same effect on reducing cloud drop size implies that the difference in Tg is due to the IFN activity. This dependence of Tg on aerosol types appears only for clouds with re-5 < 12 μm (re-5 is the cloud drop effective radius at the -5°C isotherm, above which ice rarely forms in cloud tops). For the rest of the clouds the glaciation temperature increases strongly with re-5 with little relation to the aerosol types, reaching Tg> ˜ -15°C for the largest re-5, which are typical to marine clouds in pristine atmosphere.

  14. Use of Recirculating Ventilation with Dust Filtration to Improve Wintertime Air Quality in a Swine Farrowing Room

    PubMed Central

    Anthony, T. Renée; Altmaier, Ralph; Jones, Samuel; Gassman, Rich; Park, Jae Hong; Peters, Thomas M.

    2016-01-01

    The performance of a recirculating ventilation system with dust filtration was evaluated to determine its effectiveness to improve the air quality in a swine farrowing room of a concentrated animal feeding operation (CAFO). Air was exhausted from the room (0.47 m3sec−1; 1000 cfm), treated with a filtration unit (Shaker-Dust Collector), and returned to the farrowing room to reduce dust concentrations while retaining heat necessary for livestock health. The air quality in the room was assessed over a winter, during which time limited fresh air is traditionally brought into the building. Over the study period, dust concentrations ranged from 0.005 to 0.31 mg m−3 (respirable) and 0.17 to 2.09 mg m−3 (inhalable). In-room dust concentrations were reduced (41% for respirable and 33% for inhalable) with the system in operation, while gas concentrations (ammonia [NH3], hydrogen sulfide [H2S], carbon monoxide [CO], carbon dioxide [CO2]) were unchanged. The position of the exhaust and return air systems provided reasonably uniform contaminant distributions, although the respirable dust concentrations nearest one of the exhaust ducts was statistically higher than other locations in the room, with differences averaging only 0.05 mg m−3. Throughout the study, CO2 concentrations consistently exceeded 1540 ppm (industry recommendations) and on eight of the 18 study days it exceeded 2500 ppm (50% of the ACGIH TLV), with significantly higher concentrations near a door to a temperature-controlled hallway that was typically often left open. Alternative heaters are recommended to reduce CO2 concentrations in the room. Contaminant concentrations were modeled using production and environmental factors, with NH3 related to the number of sow in the room and outdoor temperatures and CO2 related to the number of piglets and outdoor temperatures. The recirculating ventilation system provided dust reduction without increasing concentrations of hazardous gases. PMID:25950713

  15. Use of Recirculating Ventilation With Dust Filtration to Improve Wintertime Air Quality in a Swine Farrowing Room.

    PubMed

    Anthony, T Renée; Altmaier, Ralph; Jones, Samuel; Gassman, Rich; Park, Jae Hong; Peters, Thomas M

    2015-01-01

    The performance of a recirculating ventilation system with dust filtration was evaluated to determine its effectiveness to improve the air quality in a swine farrowing room of a concentrated animal feeding operation (CAFO). Air was exhausted from the room (0.47 m(3) sec(-1); 1000 cfm), treated with a filtration unit (Shaker-Dust Collector), and returned to the farrowing room to reduce dust concentrations while retaining heat necessary for livestock health. The air quality in the room was assessed over a winter, during which time limited fresh air is traditionally brought into the building. Over the study period, dust concentrations ranged from 0.005-0.31 mg m(-3) (respirable) and 0.17-2.09 mg m(-3) (inhalable). In-room dust concentrations were reduced (41% for respirable and 33% for inhalable) with the system in operation, while gas concentrations (ammonia [NH3], hydrogen sulfide [H2S], carbon monoxide [CO], carbon dioxide [CO2]) were unchanged. The position of the exhaust and return air systems provided reasonably uniform contaminant distributions, although the respirable dust concentrations nearest one of the exhaust ducts was statistically higher than other locations in the room, with differences averaging only 0.05 mg m(-3). Throughout the study, CO2 concentrations consistently exceeded 1540 ppm (industry recommendations) and on eight of the 18 study days it exceeded 2500 ppm (50% of the ACGIH TLV), with significantly higher concentrations near a door to a temperature-controlled hallway that was typically often left open. Alternative heaters are recommended to reduce CO2 concentrations in the room. Contaminant concentrations were modeled using production and environmental factors, with NH3 related to the number of sow in the room and outdoor temperatures and CO2 related to the number of piglets and outdoor temperatures. The recirculating ventilation system provided dust reduction without increasing concentrations of hazardous gases. PMID:25950713

  16. SPM and fungal spores in the ambient air of west Korea during the Asian dust (Yellow sand) period

    NASA Astrophysics Data System (ADS)

    Yeo, Hwan-Goo; Kim, Jong-Ho

    The relationship between suspended particulate matter (SPM) and fungal spore was investigated in Seosan, a rural county along the west coast of Korea, in the spring of 2000. SPM concentrations in the air were 199.8 μg m -3 in the first Asian dust period (23-24 March), 249.4 μg m -3 in the second Asian dust period (7-9 April) and 98.9 μg m -3 in the non-Asian dust period (12-16 May), respectively. The majority of the total SPM were composed of coarse particles sized about 5 μm during the two Asian dust periods. Four molds genera grown from airborne fungal spores were identified in colonies grown from SPM samples taken during the Asian dust periods. All the genera found, Fusarium, Aspergillus, Penicillium and Basipetospora, are hyphomycetes in the division Deuteromycota. Morphologically, more diversified mycelia of hyphomycetes were grown on the sample captured from 1.1 to 2.1 μm sized SPM than on the other sized samples gathered in the dust periods. On the other hand, no mold was observed on the sample of 1.1-2.1 μm sized SPM in the non-Asian dust period. From these results, it seems evident that several sorts of fine sized fungal spores were suspended in the atmospheric environment of this study area during Asian dust periods.

  17. 40 CFR 81.168 - Great Falls Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air... Intrastate Air Quality Control Region (Montana) consists of the territorial area encompassed by the boundaries of the following jurisdictions or described area (including the territorial area of...

  18. Possible Influences of Air Pollution, Dust and Sandstorms on the Indian Monsoon

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.; Kim, Kyu-Myong; Hsu, Christina N.; Holben, Brent N.

    2010-01-01

    reduced precipitation. However, in the presence of increasing moist and warm air, the reduced coalescence/collision may lead to supercooled drops at higher altitudes where ice precipitation falls and melts. The latent heat release from freezing aloft and melting below implies greater upward heat transport in polluted clouds and invigorate deep convection. In this way, aerosols may lead to increased local convection. Hence, depending on the ambient large-scale conditions and dynamical feedback processes, aerosols' effect on precipitation can be positive, negative or mixed. In the Asian monsoon and adjacent regions, the aerosol forcing and responses of the water cycle are even more complex, Both direct and indirect effects may take place locally and simultaneously, interacting with each other. in addition to local effects, monsoon rainfall may be affected by aerosols transported from other regions and intensified through large-scale circulation and moisture feedback. Thus, dust transported by the large-scale circulation from the adjacent deserts to northern India may affect rainfall over the Bay of Bengal; sulphate and black carbon front industrial pollution in central, southern China and northern India may affect the rainfall regime over the Korean peninsula and Japan; organic and black carbon front biomass burning from Indo-China may modulate the pre-monsoon rainfall regime over southern China and coastal regions, contributing to variability in differential heating and cooling of the atmosphere and to the land-sea thermal contrast. During the pre-monsoon season and monsoon breaks, it has been suggested that radiative forcing by absorbing aerosols have nearly the same order of magnitude as the forcing due to latent heating from convection and surface fluxes. The magnitude of the total aerosol radiative cooling due to sulphates and soot is of the order of 20-40 W/m2 over the Asian monsoon land region in the pre-monsoon season, compared to about 1-2 W/m2 for global warng

  19. Modification of Saharan air layer and environmental shear over the eastern Atlantic Ocean by dust-radiation effects

    NASA Astrophysics Data System (ADS)

    Chen, Shu-Hua; Wang, Sheng-Hsiang; Waylonis, Mark

    2010-11-01

    This study investigates the influence of dust-radiation effects on the modification of the Saharan air layer (SAL) and environmental shear. A tracer model based on the Weather Research and Forecast model was developed to examine the influence using a dust outbreak event. Two numerical experiments were conducted with (ON) and without (OFF) the dust-radiation effects. Both simulations reasonably reproduced SAL's features. However, the 700 hPa maximum temperature within SAL was slightly underestimated and shifted northwestward from OFF. These were improved from ON, but the maximum temperature became slightly overestimated, which might be due to inaccurate optical properties. The dust-radiation interactions mainly warmed the dusty air between 750 and 550 hPa because dust shortwave absorption dominated dust longwave cooling. Another major warming area was found near the surface over the ocean due to longwave radiative heating by dust aloft. The modification of temperature resulted in an adjustment of the vertical wind shear. To the south of SAL, where easterly wave disturbances and tropical storms usually occur, the vertical zonal wind shear increased by about 1˜2.5 m s-1 km-1 from 750 to 550 hPa, resulting in a maximum wind change of 3˜5 m s-1, a 30˜40% increase, around the top of this layer. The enhancement of the vertical shear in this layer could potentially have an impact on TC genesis and development. The dust-radiation effects also modified the moisture and dust distribution, which can have a feedback (i.e., a secondary effect) on the heating profile and the vertical shear.

  20. The UK particulate matter air pollution episode of March–April 2014: more than Saharan dust

    NASA Astrophysics Data System (ADS)

    Vieno, M.; Heal, M. R.; Twigg, M. M.; MacKenzie, I. A.; Braban, C. F.; Lingard, J. J. N.; Ritchie, S.; Beck, R. C.; Móring, A.; Ots, R.; Di Marco, C. F.; Nemitz, E.; Sutton, M. A.; Reis, S.

    2016-04-01

    A period of elevated surface concentrations of airborne particulate matter (PM) in the UK in spring 2014 was widely associated in the UK media with a Saharan dust plume. This might have led to over-emphasis on a natural phenomenon and consequently to a missed opportunity to inform the public and provide robust evidence for policy-makers about the observed characteristics and causes of this pollution event. In this work, the EMEP4UK regional atmospheric chemistry transport model (ACTM) was used in conjunction with speciated PM measurements to investigate the sources and long-range transport (including vertical) processes contributing to the chemical components of the elevated surface PM. It is shown that the elevated PM during this period was mainly driven by ammonium nitrate, much of which was derived from emissions outside the UK. In the early part of the episode, Saharan dust remained aloft above the UK; we show that a significant contribution of Saharan dust at surface level was restricted only to the latter part of the elevated PM period and to a relatively small geographic area in the southern part of the UK. The analyses presented in this paper illustrate the capability of advanced ACTMs, corroborated with chemically-speciated measurements, to identify the underlying causes of complex PM air pollution episodes. Specifically, the analyses highlight the substantial contribution of secondary inorganic ammonium nitrate PM, with agricultural ammonia emissions in continental Europe presenting a major driver. The findings suggest that more emphasis on reducing emissions in Europe would have marked benefits in reducing episodic PM2.5 concentrations in the UK.

  1. The UK particulate matter air pollution episode of March-April 2014: more than Saharan dust

    NASA Astrophysics Data System (ADS)

    Vieno, M.; Heal, M. R.; Twigg, M. M.; MacKenzie, I. A.; Braban, C. F.; Lingard, J. J. N.; Ritchie, S.; Beck, R. C.; Móring, A.; Ots, R.; Di Marco, C. F.; Nemitz, E.; Sutton, M. A.; Reis, S.

    2016-04-01

    A period of elevated surface concentrations of airborne particulate matter (PM) in the UK in spring 2014 was widely associated in the UK media with a Saharan dust plume. This might have led to over-emphasis on a natural phenomenon and consequently to a missed opportunity to inform the public and provide robust evidence for policy-makers about the observed characteristics and causes of this pollution event. In this work, the EMEP4UK regional atmospheric chemistry transport model (ACTM) was used in conjunction with speciated PM measurements to investigate the sources and long-range transport (including vertical) processes contributing to the chemical components of the elevated surface PM. It is shown that the elevated PM during this period was mainly driven by ammonium nitrate, much of which was derived from emissions outside the UK. In the early part of the episode, Saharan dust remained aloft above the UK; we show that a significant contribution of Saharan dust at surface level was restricted only to the latter part of the elevated PM period and to a relatively small geographic area in the southern part of the UK. The analyses presented in this paper illustrate the capability of advanced ACTMs, corroborated with chemically-speciated measurements, to identify the underlying causes of complex PM air pollution episodes. Specifically, the analyses highlight the substantial contribution of secondary inorganic ammonium nitrate PM, with agricultural ammonia emissions in continental Europe presenting a major driver. The findings suggest that more emphasis on reducing emissions in Europe would have marked benefits in reducing episodic PM2.5 concentrations in the UK.

  2. Influence of combined dust reducing carpet and compact air filtration unit on the indoor air quality of a classroom.

    PubMed

    Scheepers, Paul T J; de Hartog, Jeroen J; Reijnaerts, Judith; Beckmann, Gwendolyn; Anzion, Rob; Poels, Katrien; Godderis, Lode

    2015-02-01

    Primary schools mostly rely on natural ventilation but also have an interest in affordable technology to improve indoor air quality (IAQ). Laboratory tests show promising results for dust reducing carpets and compact air filtration systems but there is no information available on the performance of these interventions in actual operating classrooms. An exploratory study was performed to evaluate a combination of the two systems in a primary school. Measurements of PM-10 and PM-2.5 were performed by filter sampling and aerosol spectrometry. Other IAQ parameters included black smoke (BS), volatile organic compounds (VOC), nitrogen dioxide (NO2) and formaldehyde. Both interventions were introduced in one classroom during one week, using another classroom as a reference. In a second week the interventions were moved to the other classroom, using the first as a reference (cross-over design). In three remaining weeks the classrooms were compared without interventions. Indoor IAQ parameters were compared to the corresponding outdoor parameters using the indoor/outdoor (I/O) ratio. When the classrooms were occupied (teaching hours) interventions resulted in 27-43% reductions of PM-10, PM-2.5 and BS values. During the weekends the systems reduced these levels by 51-87%. Evaluations using the change in I/O ratios gave comparable results. Levels of VOC, NO2 and formaldehyde were rather low and a contribution of the interventions to the improvement of these gas phase IAQ parameters was inconclusive. PMID:25380291

  3. Dust particle charge screening in the dry-air plasma produced by an external ionization source

    SciTech Connect

    Derbenev, I. N.; Filippov, A. V.

    2015-08-15

    The ionic composition of the plasma produced by an external ionization source in dry air at atmospheric pressure and room temperature and the screening of the electric field of a dust particle in such a plasma have been investigated. The point sink model based on the diffusion-drift approximation has been used to solve the screening problem. We have established that the main species of ions in the plasma under consideration are O{sub 4}{sup +}, O{sub 2}{sup -}, and O{sub 4}{sup -} and that the dust particle potential distribution is described by a superposition of four exponentials with four different constants. We show that the first constant coincides with the inverse Debye length, the second is described by the inverse ambipolar diffusion length of the positive and negative plasma components in the characteristic time of their recombination, the third is determined by the conversion of negative ions, and the fourth is determined by the attachment and recombination of electrons and diatomic ions.

  4. Air Quality in Alternative Housing Systems May Have an Impact on Laying Hen Welfare. Part I—Dust

    PubMed Central

    David, Bruce; Oppermann Moe, Randi; Michel, Virginie; Lund, Vonne; Mejdell, Cecilie

    2015-01-01

    The new legislation for laying hens in the European Union put a ban on conventional cages. Production systems must now provide the hens with access to a nest, a perch, and material for dust bathing. These requirements will improve the behavioral aspects of animal welfare. However, when hens are kept with access to litter, it is a concern that polluted air may become an increased threat to health and therefore also a welfare problem. This article reviews the literature regarding the health and welfare effects birds experience when exposed to barn dust. Dust is composed of inorganic and organic compounds, from the birds themselves as well as from feed, litter, and building materials. Dust may be a vector for microorganisms and toxins. In general, studies indicate that housing systems where laying hens have access to litter as aviaries and floor systems consistently have higher concentrations of suspended dust than caged hens with little (furnished cages) or no access to litter (conventional cages). The higher dust levels in aviaries and floor housing are also caused by increased bird activity in the non-cage systems. There are gaps in both the basic and applied knowledge of how birds react to dust and aerosol contaminants, i.e., what levels they find aversive and/or impair health. Nevertheless, high dust levels may compromise the health and welfare of both birds and their caretakers and the poor air quality often found in new poultry housing systems needs to be addressed. It is necessary to develop prophylactic measures and to refine the production systems in order to achieve the full welfare benefits of the cage ban. PMID:26479370

  5. Dust and Pollution Aerosol Air Mass Mapping from Satellite Multi-angle Imaging

    NASA Astrophysics Data System (ADS)

    Kahn, R. A.; Nelson, D. L.; Yau, K. S.; Martonchik, J.; Diner, D. J.; Gaitley, B. J.; Russell, P.; Livingston, J.; Redemann, J.; Quinn, P. R.; Clarke, A. R.; Howell, S.; McNaughton, C.; Reid, J.; Holben, B.; Wendisch, M.; Petzold, A.

    2006-12-01

    One objective of the NASA Earth Observing System's Multi-angle Imaging SpectroRadiometer (MISR) is to map aerosol air mass types, based on retrieved column-average particle microphysical properties. Early results demonstrated the ability to distinguish three-to-five bins over the 0.1 to 2.5 micron aerosol size range, about two-to-four groupings of single-scattering albedo, and to separate spherical from randomly oriented non- spherical particles, under good but not ideal viewing conditions. These results relied heavily on the MISR Research Aerosol Retrieval algorithm, which allows flexibility in choosing retrieval patch size and location, component aerosol properties and mixtures, and mixture acceptance criteria, compared to early versions of the MISR Standard algorithm, designed to routinely process the entire global data set. Early mid-visible column aerosol optical depth results were validated against surface-based sun photometer measurements. The corresponding particle property results appeared qualitatively promising, but formal validation requires quantitative constraints on component particle properties and mixtures in a range of natural settings, available mainly from the combination of height-resolved and total column data collected by surface and airborne instruments during field campaigns. This presentation will highlight the latest detailed, multi-platform case studies, as well as MISR regional mapping, of smoke, Saharan dust, and mixtures of pollution aerosol and desert dust collected during the INTEX, SAMUM, and UAE-2 campaigns, respectively. The broader implications of these results for global, and especially regional, aerosol climate and air quality studies will also be discussed. This work is performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  6. Incorporation of the Wind Erosion Prediction System (WEPS) for dust into a regional air quality modeling system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion of soil is a major concern of the agricultural community as it removes the most fertile part of the soil and thus degrades soil productivity. Furthermore, suspension of eroded soil particles results in dust emissions into the atmosphere, contributing to poor air quality, reduced visibi...

  7. MCCM-WEPS: A computational tool to study and evaluate air pollution by dust particles over Mexico City

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since natural dust emissions are an important factor in the air quality of Mexico City, a modeling effort to quantify and locate its sources and evaluate their impact on the population is presented. The system obtained from coupling Multiscale Climate and Chemistry Model (MCCM) and Wind Erosion Pred...

  8. Low-flow, long-term air sampling under normal domestic activity to measure house dust mite and cockroach allergens.

    PubMed

    Park, Jung Won; Kim, Cheol Woo; Kang, Dae Bong; Lee, In Young; Choi, Soo Young; Yong, Tai-Soon; Shin, Dong Cheon; Kim, Kyu Earn; Hong, Chein-Soo

    2002-01-01

    Successful applications of air sampling for the quantification of exposure to indoor allergens have been reported, but its efficiency is still controversial. We evaluated whether the low-flow, long-term air sampling in normal domestic activity conditions can quantify the exposure of house dust mites (HDM) and cockroaches (CR) allergens or not. Airborne Der f 1 and Bla g 1 were captured with a personal air sampler in 25 bedrooms during normal domestic activity. Quantification of the major allergens in the reservoir dust and the extraction of the air sampler filters were done with two-site ELISA kits. Airborne Der f 1 was measured above the threshold level of detection in 15 houses (60%). Detection rate of airborne Der f 1 was significantly higher in those houses where D. farinae was microscopically found in the reservoir dusts (76.5% vs. 25%, chi 2 = 6.0, p = 0.014). Airborne Der f 1 was more frequently detected in the houses with higher Der f 1 (> or = 10 micrograms/g dust) in bedding reservoir dust than the other group (91% vs. 35.7%, chi 2 = 7.819, p = 0.005), and the median value of airborne Der f 1 was also significantly higher in that group (14.0 pg/m3 vs. below detection limit, p = 0.002). Airborne Der f 1 was significantly correlated with Der f 1 in bedding reservoir dust (r = 0.591, p < 0.01). Airborne Bla g 1 was measured with ELISA in 16 houses (64%), and it was more frequently detected in the houses where the CRs were captured by adhesive traps (91% vs. 57%, chi 2 = 3,484, p = 0.06). The median concentration of Bla g 1 in the filter was also higher in the houses with captured CRs (0.12 vs. 0.05 mU/m3, p = 0.06), but the level of Bla g 1 did not correlate with that of the bedding dusts or the floor dusts of kitchen. These results suggested that airborne HDM or CR allergens could be measured by low-flow, long-term air sampling, and that it might be one of appropriate modalities for evaluating personal exposure to HDM and CR allergens. PMID:12926189

  9. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean

    USGS Publications Warehouse

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

    2014-01-01

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9–126 ng/m3 (mean = 25 ± 34) at source and 0.05–0.71 ng/m3 (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1–3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses.

  10. Persistent organic contaminants in Saharan dust air masses in West Africa, Cape Verde and the eastern Caribbean.

    PubMed

    Garrison, V H; Majewski, M S; Foreman, W T; Genualdi, S A; Mohammed, A; Massey Simonich, S L

    2014-01-15

    Anthropogenic semivolatile organic compounds (SOCs) that persist in the environment, bioaccumulate, are toxic at low concentrations, and undergo long-range atmospheric transport (LRT) were identified and quantified in the atmosphere of a Saharan dust source region (Mali) and during Saharan dust incursions at downwind sites in the eastern Caribbean (U.S. Virgin Islands, Trinidad and Tobago) and Cape Verde. More organochlorine and organophosphate pesticides (OCPPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCB) congeners were detected in the Saharan dust region than at downwind sites. Seven of the 13 OCPPs detected occurred at all sites: chlordanes, chlorpyrifos, dacthal, dieldrin, endosulfans, hexachlorobenzene (HCB), and trifluralin. Total SOCs ranged from 1.9-126 ng/m(3) (mean = 25 ± 34) at source and 0.05-0.71 ng/m(3) (mean = 0.24 ± 0.18) at downwind sites during dust conditions. Most SOC concentrations were 1-3 orders of magnitude higher in source than downwind sites. A Saharan source was confirmed for sampled air masses at downwind sites based on dust particle elemental composition and rare earth ratios, atmospheric back trajectory models, and field observations. SOC concentrations were considerably below existing occupational and/or regulatory limits; however, few regulatory limits exist for these persistent organic compounds. Long-term effects of chronic exposure to low concentrations of SOCs are unknown, as are possible additive or synergistic effects of mixtures of SOCs, biologically active trace metals, and mineral dust particles transported together in Saharan dust air masses. PMID:24055669

  11. 40 CFR 81.85 - Metropolitan Sioux Falls Interstate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Clean Air Act, 42 U.S.C. 1857h(f)) geographically located within the outermost boundaries of the area so..., Minnehaha County, Turner County. Note: For purposes of identification, this Region is referred to...

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

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, R.; Rajkumar, P.

    2014-11-01

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

  13. 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. PMID:6885451

  14. Dust Control with Use of Air-Water Spraying System / Redukcja Zapylenia Powietrza Z Wykorzystaniem Zraszania Powietrzno-Wodnego

    NASA Astrophysics Data System (ADS)

    Prostański, Dariusz

    2012-12-01

    Results from testing the dust control efficiency, when using air-water spraying system in comparison to the typical water spraying system are presented in the paper. The tests were carried out in conditions of longwall mining and at the places of run-of-mine transportation. Also the results of stand tests of different types of nozzles both for air-water and for water spaying systems carried out at KOMAG's laboratory and in real conditions are presented. The benefits resulting from air-water spraying system have been determined.

  15. An air quality forecasting system in Beijing--application to the study of dust storm events in China in May 2008.

    PubMed

    Zhang, Qijie; Laurent, Benoit; Velay-Lasry, Fanny; Ngo, Richard; Derognat, Claude; Marticorena, Béatrice; Albergel, Armand

    2012-01-01

    An air pollution forecast system, ARIA Regional, was implemented in 2007-2008 at the Beijing Municipality Environmental Monitoring Center, providing daily forecast of main pollutant concentrations. The chemistry-transport model CHIMERE was coupled with the dust emission model MB95 for restituting dust storm events in springtime so as to improve forecast results. Dust storm events were sporadic but could be extremely intense and then control air quality indexes close to the source areas but also far in the Beijing area. A dust episode having occurred at the end of May 2008 was analyzed in this article, and its impact of particulate matter on the Chinese air pollution index (API) was evaluated. Following our estimation, about 23 Tg of dust were emitted from source areas in Mongolia and in the Inner Mongolia of China, transporting towards southeast. This episode of dust storm influenced a large part of North China and East China, and also South Korea. The model result was then evaluated using satellite observations and in situ data. The simulated daily concentrations of total suspended particulate at 6:00 UTC had a similar spatial pattern with respect to OMI satellite aerosol index. Temporal evolution of dust plume was evaluated by comparing dust aerosol optical depth (AOD) calculated from the simulations with AOD derived from MODIS satellite products. Finally, the comparison of reported Chinese API in Beijing with API calculated from the simulation including dust emissions had showed the significant improvement of the model results taking into account mineral dust correctly. PMID:22783620

  16. Spatiotemporal analysis and human exposure assessment on polycyclic aromatic hydrocarbons in indoor air, settled house dust, and diet: A review.

    PubMed

    Ma, Yuning; Harrad, Stuart

    2015-11-01

    This review summarizes the published literature on the presence of polycyclic aromatic hydrocarbons (PAH) in indoor air, settled house dust, and food, and highlights geographical and temporal trends in indoor PAH contamination. In both indoor air and dust, ΣPAH concentrations in North America have decreased over the past 30 years with a halving time of 6.7±1.9years in indoor air and 5.0±2.3 years in indoor dust. In contrast, indoor PAH concentrations in Asia have remained steady. Concentrations of ΣPAH in indoor air are significantly (p<0.01) higher in Asia than North America. In studies recording both vapor and particulate phases, the global average concentration in indoor air of ΣPAH excluding naphthalene is between 7 and 14,300 ng/m(3). Over a similar period, the average ΣPAH concentration in house dust ranges between 127 to 115,817ng/g. Indoor/outdoor ratios of atmospheric concentrations of ΣPAH have declined globally with a half-life of 6.3±2.3 years. While indoor/outdoor ratios for benzo[a]pyrene toxicity equivalents (BaPeq) declined in North America with a half-life of 12.2±3.2 years, no significant decline was observed when data from all regions were considered. Comparison of the global database, revealed that I/O ratios for ΣPAH (average=4.3±1.3), exceeded significantly those of BaPeq (average=1.7±0.4) in the same samples. The significant decline in global I/O ratios suggests that indoor sources of PAH have been controlled more effectively than outdoor sources. Moreover, the significantly higher I/O ratios for ΣPAH compared to BaPeq, imply that indoor sources of PAH emit proportionally more of the less carcinogenic PAH than outdoor sources. Dietary exposure to PAH ranges from 137 to 55,000 ng/day. Definitive spatiotemporal trends in dietary exposure were precluded due to relatively small number of relevant studies. However, although reported in only one study, PAH concentrations in Chinese diets exceeded those in diet from other parts of the

  17. [Use of dust and air as indicators of environmental pollution in areas adjacent to a source of stationary lead emission].

    PubMed

    Quiterio, S L; da Silva, C R; Vaitsman, D S; Martinhon, P T; Moreira, M F; Araújo, U C; Mattos, R C; Santos, L S

    2001-01-01

    This study measured lead concentrations in both the outdoor air and household dust from houses located around a lead-acid battery repair shop. Such installations are one of the largest sources of lead exposure, since outdated technology is still used, coupled with the lack of strict air-quality control programs. Measurements of the air lead concentration around the repair shop were carried out at 6 points, approximately 25 and 500 m from the shop. Over 50% of the air samples exceeded the limit of 1.5 microg Pb.m-3 (range 0.03 - 183.3 microg Pb.m-3). House dust samples were collected from 6 places in houses located at approximately 25, 50, and 500 m from the repair shop, and the concentration of 1,500 microg Pb.m-2 for lead in house dust was exceeded in 44% of the samples, with results varying from 2.2 to 54,338.9 microg Pb.m-2. PMID:11395788

  18. An Appalachian isochron: a kaolinized Carboniferous air-fall volcanic-ash deposit (tonstein)

    USGS Publications Warehouse

    Lyons, P.C.

    1992-01-01

    The Fire Clay tonstein is a kaolinized, airfall volcanic ash bed that was deposited in a widespread late Carboniferous peat-forming mire. Eleven samples from Kentucky and West Virginia, spanning a distance of 200km, and two samples from Tennessee and Virginia indicate a characteristic mineralogical signature. A high-silica alkalic rhyolitic source is suggested by the geochemistry of immobile elements and by electron-probe analyses of glass inclusions. 40Ar/39Ar sanidine plateau dating indicates an age of 312??1 Ma for the Fire Clay tonstein, which is consistent with previous 40Ar/39Ar dates for this tonstein. A new isopachous map of the Fire Clay ash-fall deposit indicates an area of 37 000km2 and a probable source to the present-day southwest. -from Authors

  19. Chemical compositions and radiative properties of dust and anthropogenic air masses study in Taipei Basin, Taiwan, during spring of 2004

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Yu; Fang, Guor-Cheng; Chou, Charles C.-K.; Chen, Wei-Nai

    Asia is one of the major sources of not only mineral dust but also anthropogenic aerosols. Continental air masses associated with the East Asian winter monsoon always contain high contents of mineral dust and anthropogenic species and transported southeastward to Taiwan, which have significant influences on global atmospheric radiation transfer directly by scattering and absorbing solar radiation in each spring. However, few measurements for the long-range transported aerosol and its optical properties were announced in this area, between the Western Pacific and the southeastern coast of Mainland China. The overall objective of this work is to quantify the optical characteristics of different aerosol types in the Eastern Asian. In order to achieve this objective, meteorological parameters, concentrations of PM 10 and its soluble species, and optical property of atmospheric scattering coefficients were measured continuously with 1 h time-resolved from 11 February to 7 April 2004 in Taipei Basin (25°00'N, 121°32'E). In this work, the dramatic changes of meteorological parameters such as temperature and winds were used to determine the influenced period of each air mass. Continental, strong continental, marine, and stagnant air masses defined by the back-trajectory analysis and local meteorology were further characterized as long-range transport pollution, dust, clean marine, and local pollution aerosols, respectively, according to the diagnostic ratios. The aerosol mass scattering efficiency of continental pollution, dust, clean marine, and local pollution aerosols were ranged from 1.3 to 1.6, 0.7 to 1.0, 1.4 and 1.4 to 2.3 m 2 g -1, respectively. Overall, there are two distinct populations of aerosol mass scattering efficiencies, one for an aerosol chemical composition dominated by dust (<1.0 m 2 g -1) and the other for an aerosol chemical composition dominated by anthropogenic pollutants (1.3-2.3 m 2 g -1), which were similar to the previous measurements with

  20. 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.

  1. Detection of internally mixed Asian dust with air pollution aerosols using a polarization optical particle counter and a polarization-sensitive two-wavelength lidar

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    East Asia is a unique region where mineral dust (Asian dust) sources are located near urban and industrial areas. Asian dust is often mixed with air pollution aerosols during transportation. It is important to understand the mixing states of Asian dust and other aerosols, because the effects on the environment and human health differ depending on the mixing state. We studied the mixing states of Asian dust using a polarization particle counter (POPC) that measures the forward scattering and the two polarization components of backscattering for single particles and a polarization-sensitive (532 nm) two-wavelength (1064 nm and 532 nm) lidar. We conducted the simultaneous observations using the POPC and the lidar in Seoul from March to December 2013 and captured the characteristics of pure Asian dust and internally mixed polluted Asian dust. POPC measurements indicated that the density of large particles was lower in polluted Asian dust that transported slowly over the polluted areas than in pure Asian dust that transported quickly from the dust source region. Moreover, the backscattering depolarization ratio was smaller for all particle sizes in polluted dust. The optical characteristics measured using the lidar were consistent with the POPC measurements. The backscattering color ratio of polluted dust was comparable to that of pure dust, but the depolarization ratio was lower for polluted dust. In addition, coarse non-spherical particles (Asian dust) almost always existed in the background, and the depolarization ratio had seasonal variation with a lower depolarization ratio in the summer. These results suggest background Asian dust particles are internally mixed in the summer.

  2. Investigation of Techniques to Improve Continuous Air Monitors Under Conditions of High Dust Loading in Environmental Settings

    SciTech Connect

    Suilou Huang; Stephen D. Schery; John C. Rodgers

    2002-07-23

    A number of DOE facilities, such as the Los Alamos National Laboratory (LANL) and the Waste Isolation Pilot Plant (WIPP), use alpha-particle environmental continuous air monitors (ECAMs) to monitor air for unwanted releases of radioactive aerosols containing such materials as plutonium and uranium. High sensitivity, ease of operation, and lack of false alarms are all important for ECAMs. The object of the project was to conduct investigations to improve operation of ECAMs, particularly under conditions where a lot of nonradioactive dust may be deposited on the filters (conditions of high dust loading). The presence of such dust may increase the frequency with which filters must be changed and can lead to an increased incidence of false alarms due to deteriorated energy resolution and response specificity to the radionuclides of interest. A major finding of the investigation, not previously documented, was that under many conditions thick layers of underlying nonradioactive dust do not decrease energy resolution and specificity for target radionuclides if the radioactive aerosol arrives as a sudden thin burst deposit, as commonly occurs in the early-warning alarm mode. As a result, operators of ECAMs may not need to change filters as often as previously thought and have data upon which to base more reliable operating procedures.

  3. CALIPSO Satellite Lidar Identification Of Elevated Dust Over Australia Compared With Air Quality Model PM60 Forecasts

    NASA Technical Reports Server (NTRS)

    Young, Stuart A.; Vaughan, Mark; Omar, Ali; Liu, Zhaoyan; Lee, Sunhee; Hu, Youngxiang; Cope, Martin

    2008-01-01

    Global measurements of the vertical distribution of clouds and aerosols have been recorded by the lidar on board the CALIPSO (Cloud Aerosol Lidar Infrared Pathfinder Satellite Observations) satellite since June 2006. Such extensive, height-resolved measurements provide a rare and valuable opportunity for developing, testing and validating various atmospheric models, including global climate, numerical weather prediction, chemical transport and air quality models. Here we report on the initial results of an investigation into the performance of the Australian Air Quality Forecast System (AAQFS) model in forecasting the distribution of elevated dust over the Australian region. The model forecasts of PM60 dust distribution are compared with the CALIPSO lidar Vertical Feature Mask (VFM) data product. The VFM classifies contiguous atmospheric regions of enhanced backscatter as either cloud or aerosols. Aerosols are further classified into six subtypes. By comparing forecast PM60 concentration profiles to the spatial distribution of dust reported in the CALIPSO VFM, we can assess the model s ability to predict the occurrence and the vertical and horizontal extents of dust events within the study area.

  4. Evaluation of Ag nanoparticle coated air filter against aerosolized virus: Anti-viral efficiency with dust loading.

    PubMed

    Joe, Yun Haeng; Park, Dae Hoon; Hwang, Jungho

    2016-01-15

    In this study, the effect of dust loading on the anti-viral ability of an anti-viral air filter was investigated. Silver nanoparticles approximately 11 nm in diameter were synthesized via a spark discharge generation system and were used as anti-viral agents coated onto a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter against aerosolized bacteriophage MS2 virus particles were tested with dust loading. The filtration efficiency and pressure drop increased with dust loading, while the anti-viral ability decreased. Theoretical analysis of anti-viral ability with dust loading was carried out using a mathematical model based on that presented by Joe et al. (J. Hazard. Mater.; 280: 356-363, 2014). Our model can be used to compare anti-viral abilities of various anti-viral agents, determine appropriate coating areal density of anti-viral agent on a filter, and predict the life cycle of an anti-viral filter. PMID:26434534

  5. [Aerosol deposition in nasal passages of burrowing and ground rodents when breathing dust-laden air].

    PubMed

    Moshkin, M P; Petrovskiĭ, D V; Akulov, A E; Romashchenko, A V; Gerlinskaia, L A; Muchnaia, M I; Ganimedov, V L; Sadovskiĭ, A S; Savelov, A A; Koptiug, I V; Troitskiĭ, S Iu; Bukhtiiarov, V I; Kolchanov, N A; Sagdeev, R Z; Fomin, V M

    2014-01-01

    In subterranean rodents, which dig down the passages with frontal teeth, adaptation to the underground mode of life presumes forming of mechanisms that provide protection against inhaling dust particles of different size when digging. One of such mechanisms can be specific pattern of air flow organization in the nasal cavity. To test this assumption, comparative study of geometry and aerodynamics of nasal passages has been conducted with regard to typical representative of subterranean rodents, the mole vole, and a representative of ground rodents, the house mouse. Numerical modeling of air flows and deposition of micro- and nanoparticle aerosols indicates that sedimentation of model particles over the whole surface of nasal cavity is higher in mole vole than in house mouse. On the contrary, particles deposition on the surface of olfactory epithelium turns out to be substantially less in the burrowing rodent as compared to the ground one. Adaptive significance of the latter observation has been substantiated by experimental study on the uptake ofnanoparticles of hydrated manganese oxide MnO x (H2O)x and Mn ions from nasal cavity into brain. It has been shown with use of magnetic resonance tomography method that there is no difference between studied species with respect to intake of particles or ions by olfactory bulb when they are introduced intranasally. Meanwhile, when inhaling nanoparticle aerosol of MnCl2, deposition of Mn in mouse's olfactory bulbs surpasses markedly that in vole's bulbs. Thereby, the morphology of nasal passages as a factor determining the aerodynamics of upper respiratory tract ensures for burrowing rodents more efficient protection of both lungs and brain against inhaled aerosols than for ground ones. PMID:25771679

  6. Characterization, identification of ambient air and road dust polycyclic aromatic hydrocarbons in central Taiwan, Taichung.

    PubMed

    Fang, Guor-Cheng; Chang, Cheng-Nan; Wu, Yuh-Shen; Fu, Peter Pi-Cheng; Yang, I-Lin; Chen, Ming-Hsiang

    2004-07-01

    The concentrations of ambient air polycyclic aromatic hydrocarbons (PAHs) were measured simultaneously in an industrial area (Taichung Industrial Park, TIP) and suburban area (Tunghai University, THU) in central Taiwan, Taichung. A total of samples were collected simultaneously at the two sites between August 2002 and March 2003. Particle-bound PAHs (p-PAHs) were collected on quartz filters and gas-phase PAHs (g-PAHs) on glass cartridges using polyurethane foam sampler, respectively. Both types of samples were extracted with dichloromethane/n-hexane mixture (50/50, v/v) for 24 h, then the extracts were subjected to gas chromatography/mass spectrometric analysis. Moreover, the roadside dust particle PAHs composition were also collected and analyzed at TIP, THU and traffic road sampling sites. The five main road lines in Taichung City were selected as traffic road sampling sites. Correlation studies between PAHs concentrations and meteorological parameters were revealed that temperature has greater effects (P>0.6) than other meteorological parameters such as wind speed, relative humidity and atmospheric pressure on g-PAHs and p-PAHs. PAHs sources were resolved by using principal component analysis and diagnostic ratios. The major sources of PAHs were combustion, traffic vehicle exhaust (diesel and gasoline engine), incinerator and industrial stationary sources at both sampling sites in central Taiwan. PMID:15172577

  7. Cycling of Lead Through Soil, Air, and Household Dust in El Paso, Texas

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    Elimination of leaded gasoline in the US is associated with a dramatic overall decrease in ambient lead in the environment and blood lead levels in our population. However, Pb is such a potent neurotoxin for children during the formative growth years that legislation for additional reduction of airborne lead levels is under consideration. X-ray absorption spectroscopy of a suite of samples of local (El Paso) soil, airborne particulate matter, and household dust reveals that lead humate is the dominant Pb species in these diverse environmental materials. Lead humate is a stable complex of Pb with the humus component of soil, a product of interaction between the humus and such introduced contaminant lead species as lead oxide, lead sulfate, etc. Because lead humate forms only in soil, we conclude that the source of the majority of the lead in El Paso's airborne particulate matter and household dust is local soils. Analysis of lead isotopes in selected samples is consistent with this conclusion. Re-entrainment of low-density (relative to most Pb species) humus soil particles is the apparent pathway from soil to air. Deposition of airborne particulate matter and pedal traction are the presumed mechanisms for transfer to household interiors. Reduction of airborne lead in El Paso by reducing input from its dominant local source may require extensive soil remediation, a tedious and expensive prospect. X-Ray absorption spectroscopy experiments were conducted at the Stanford Synchrotron Radiation Laboratory on beam lines 7-3, 10-2, and 11-2. Spectra were collected at the Pb L-III absorption edge in fluorescence mode using a 13-element or a 30-element Ge solid-state detector. This publication was made possible by grant numbers 1RO1-ES11367 and 1 S11 ES013339-04 from the National Institute of Environmental Health Sciences (NIEHS), NIH. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH. Partial

  8. Stenotrophomonas, Mycobacterium, and Streptomyces in home dust and air: Associations with moldiness and other home/family characteristics

    PubMed Central

    Kettleson, Eric; Kumar, Sudhir; Reponen, Tiina; Vesper, Stephen; Méheust, Delphine; Grinshpun, Sergey A.; Adhikari, Atin

    2013-01-01

    Respiratory illnesses have been linked to children’s exposures to water-damaged homes. Therefore, understanding the microbiome in water-damaged homes is critical to preventing these illnesses. Few studies have quantified bacterial contamination, especially specific species, in water-damaged homes. We collected air and dust samples in twenty-one low-mold homes and twenty-one high-mold homes. The concentrations of three bacteria/genera, Stenotrophomonas maltophilia, Streptomyces sp. and Mycobacterium sp., were measured in air and dust samples using quantitative PCR (QPCR). The concentrations of the bacteria measured in the air samples were not associated with any specific home characteristic based on multiple regression models. However, higher concentrations of S. maltophilia in the dust samples were associated with water damage, i.e. with higher floor surface moisture and higher concentrations of moisture-related mold species. The concentrations of Streptomyces and Mycobacterium sp. had similar patterns and may be partially determined by human and animal occupants and outdoor sources of these bacteria. PMID:23397905

  9. The Influence of African Dust on Air Quality in the Caribbean Basin: An Integrated Analysis of Satellite Retrievals, Ground Observations, and Model Simulations

    NASA Astrophysics Data System (ADS)

    Yu, H.; Prospero, J. M.; Chin, M.; Randles, C. A.; da Silva, A.; Bian, H.

    2015-12-01

    Long-term surface measurements in several locations extending from northeastern coast of South America to Miami in Florida have shown that African dust arrives in the Greater Caribbean Basin throughout a year. This long-range transported dust frequently elevates the level of particulate matter (PM) above the WHO guideline for PM10, which raises a concern of possible adverse impact of African dust on human health in the region. There is also concern about how future climate change might affect dust transport and its influence on regional air quality. In this presentation we provide a comprehensive characterization of the influence of African dust on air quality in the Caribbean Basin via integrating the ground observations with satellite retrievals and model simulations. The ground observations are used to validate and evaluate satellite retrievals and model simulations of dust, while satellite measurements and model simulations are used to extend spatial coverage of the ground observations. An analysis of CALIPSO lidar measurements of three-dimensional distribution of aerosols over 2007-2014 yields altitude-resolved dust mass flux into the region. On a basis of 8-year average and integration over the latitude zone of 0°-30°N, a total of 76 Tg dust is imported to the air above the Greater Caribbean Basin, of which 34 Tg (or 45%) is within the lowest 1 km layer and most relevant to air quality concern. The seasonal and interannual variations of the dust import are well correlated with ground observations of dust in Cayenne, Barbados, Puerto Rico, and Miami. We will also show comparisons of the size-resolved dust amount from both NASA GEOS-5 aerosol simulation and MERRA-2 aerosol reanalysis (i.e., column aerosol loading being constrained by satellite measurements of radiance at the top of atmosphere) with the ground observations and satellite measurement.

  10. Phthalates in German daycare centers: occurrence in air and dust and the excretion of their metabolites by children (LUPE 3).

    PubMed

    Fromme, H; Lahrz, T; Kraft, M; Fembacher, L; Dietrich, S; Sievering, S; Burghardt, R; Schuster, R; Bolte, G; Völkel, W

    2013-11-01

    Phthalates have been used for decades in large quantities, leading to the ubiquitous exposure of the population. In an investigation of 63 German daycare centers, indoor air and dust samples were analyzed for the presence of 10 phthalate diesters. Moreover, 10 primary and secondary phthalate metabolites were quantified in urine samples from 663 children attending these facilities. In addition, the urine specimens of 150 children were collected after the weekend and before they went to daycare centers. Di-isobutyl phthalate (DiBP), dibutyl phthalate (DnBP), and di-2-ethylhexyl phthalate (DEHP) were found in the indoor air, with median values of 468, 227, and 194ng/m(3), respectively. In the dust, median values of 888mg/kg for DEHP and 302mg/kg for di-isononyl phthalate (DiNP) were observed. DnBP and DiBP were together responsible for 55% of the total phthalate concentration in the indoor air, whereas DEHP and DiNP were responsible for 70% and 24% of the total phthalate concentration in the dust. Median concentrations in the urine specimens were 44.7μg/l for the DiBP monoester, 32.4μg/l for the DnBP monoester, and 16.5μg/l and 17.9μg/l for the two secondary DEHP metabolites. For some phthalates, we observed significant correlations between their concentrations in the indoor air and dust and their corresponding metabolites in the urine specimens using bivariate analyses. In multivariate analyses, the concentrations in dust were not associated with urinary metabolite excretion after controlling for the concentrations in the indoor air. The total daily "high" intake levels based on the 95th percentiles calculated from the biomonitoring data were 14.1μg/kg b.w. for DiNP and 11.9μg/kg b.w. for DEHP. Compared with tolerable daily intake (TDI) values, our "high" intake was 62% of the TDI value for DiBP, 49% for DnBP, 24% for DEHP, and 9% for DiNP. For DiBP, the total daily intake exceeded the TDI value for 2.4% of the individuals. Using a cumulative risk

  11. Characterization of the bacterial and fungal microbiome in indoor dust and outdoor air samples: a pilot study.

    PubMed

    Hanson, Blake; Zhou, Yanjiao; Bautista, Eddy J; Urch, Bruce; Speck, Mary; Silverman, Frances; Muilenberg, Michael; Phipatanakul, Wanda; Weinstock, George; Sodergren, Erica; Gold, Diane R; Sordillo, Joanne E

    2016-06-15

    Environmental microbes have been associated with both protective and adverse health effects in children and adults. Epidemiological studies often rely on broad biomarkers of microbial exposure (i.e. endotoxin, 1 → 3-beta-d-glucan), but fail to identify the taxonomic composition of the microbial community. Our aim was to characterize the bacterial and fungal microbiome in different types of environmental samples collected in studies of human health effects. We determined the composition of microbial communities present in home, school and outdoor air samples by amplifying and sequencing regions of rRNA genes from bacteria (16S) and fungi (18S and ITS). Samples for this pilot study included indoor settled dust (from both a Boston area birth cohort study on Home Allergens and Asthma (HAA) (n = 12) and a study of school exposures and asthma symptoms (SICAS) (n = 1)), as well as fine and coarse concentrated outdoor ambient particulate (CAP) samples (n = 9). Sequencing of amplified 16S, 18S, and ITS regions was performed on the Roche-454 Life Sciences Titanium pyrosequencing platform. Indoor dust samples were dominated by Gram-positive bacteria (Firmicutes and Actinobacteria); the most abundant bacterial genera were those related to human flora (Streptococcus, Staphylococcus, Corynebacterium and Lactobacillus). Outdoor CAPs were dominated by Gram-negative Proteobacteria from water and soil sources, in particular the genera Acidovorax, and Brevundimonas (which were present at very low levels or entirely absent in indoor dust). Phylum-level fungal distributions identified by 18S or ITS regions showed very similar findings: a predominance of Ascomycota in indoor dust and Basidiomycota in outdoor CAPs. ITS sequencing of fungal genera in indoor dust showed significant proportions of Aureobasidium and Leptosphaerulina along with some contribution from Cryptococcus, Epicoccum, Aspergillus and the human commensal Malassezia. ITS sequencing detected more than 70 fungal genera

  12. Tri-decabrominated diphenyl ethers and hexabromocyclododecane in indoor air and dust from Stockholm microenvironments 2: indoor sources and human exposure.

    PubMed

    de Wit, Cynthia A; Björklund, Justina Awasum; Thuresson, Kaj

    2012-02-01

    Data on polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) concentrations from Stockholm, Sweden, indoor microenvironments were combined with information from detailed questionnaires regarding the sampling location characteristics, including furnishing and equipment present. These were used to elucidate relationships between possible flame-retarded sources and the contaminant concentrations found in air and dust. Median concentration ranges of ΣPenta-, ΣOcta-, ΣDecaBDE and HBCD from all microenvironments were 19-570, 1.7-280, 29-3200 and <1.6-2 pg/m(3) in air and 22-240, 6.1-80, 330-1400 and 45-340 ng/g in dust, respectively. Significant correlations were found between concentrations of some PBDEs and HBCD in air and/or dust and the presence of electronic/electrical devices, foam furniture, PUF mattresses and synthetic bed pillows in, as well as floor area and construction year of the microenvironment. Car interiors were a source to indoor air in dealership halls. Using median and maximum concentrations of ΣPenta-, ΣOcta-, ΣDecaBDE and HBCD in air and dust, adult and toddler (12-24 months) intakes from inhalation and dust ingestion were estimated. Toddlers had higher estimated intakes of ΣPenta-, ΣDecaBDE and HBCD (7.8, 43, 7.6 ng/d, respectively) from dust ingestion than adults (5.8, 38, 6.0 ng/d, respectively). Air inhalation in offices was also an important exposure pathway for ΣPenta-, ΣOcta- and ΣDecaBDE in adults. For ΣPentaBDE and HBCD, air inhalation and dust ingestion play minor roles when compared to previously published Swedish dietary intakes (median exposures). However, in worst case scenarios using maximum concentrations, dust ingestion may represent 77 and 95% of toddler intake for ΣPentaBDE and HBCD, respectively. PMID:22208754

  13. Comprehensive Study of Human External Exposure to Organophosphate Flame Retardants via Air, Dust, and Hand Wipes: The Importance of Sampling and Assessment Strategy.

    PubMed

    Xu, Fuchao; Giovanoulis, Georgios; van Waes, Sofie; Padilla-Sanchez, Juan Antonio; Papadopoulou, Eleni; Magnér, Jorgen; Haug, Line Småstuen; Neels, Hugo; Covaci, Adrian

    2016-07-19

    We compared the human exposure to organophosphate flame retardants (PFRs) via inhalation, dust ingestion, and dermal absorption using different sampling and assessment strategies. Air (indoor stationary air and personal ambient air), dust (floor dust and surface dust), and hand wipes were sampled from 61 participants and their houses. We found that stationary air contains higher levels of ΣPFRs (median = 163 ng/m(3), IQR = 161 ng/m(3)) than personal air (median = 44 ng/m(3), IQR = 55 ng/m(3)), suggesting that the stationary air sample could generate a larger bias for inhalation exposure assessment. Tris(chloropropyl) phosphate isomers (ΣTCPP) accounted for over 80% of ΣPFRs in both stationary and personal air. PFRs were frequently detected in both surface dust (ΣPFRs median = 33 100 ng/g, IQR = 62 300 ng/g) and floor dust (ΣPFRs median = 20 500 ng/g, IQR = 30 300 ng/g). Tris(2-butoxylethyl) phosphate (TBOEP) accounted for 40% and 60% of ΣPFRs in surface and floor dust, respectively, followed by ΣTCPP (30% and 20%, respectively). TBOEP (median = 46 ng, IQR = 69 ng) and ΣTCPP (median = 37 ng, IQR = 49 ng) were also frequently detected in hand wipe samples. For the first time, a comprehensive assessment of human exposure to PFRs via inhalation, dust ingestion, and dermal absorption was conducted with individual personal data rather than reference factors of the general population. Inhalation seems to be the major exposure pathway for ΣTCPP and tris(2-chloroethyl) phosphate (TCEP), while participants had higher exposure to TBOEP and triphenyl phosphate (TPHP) via dust ingestion. Estimated exposure to ΣPFRs was the highest with stationary air inhalation (median =34 ng·kg bw(-1)·day(-1), IQR = 38 ng·kg bw(-1)·day(-1)), followed by surface dust ingestion (median = 13 ng·kg bw(-1)·day(-1), IQR = 28 ng·kg bw(-1)·day(-1)), floor dust ingestion and personal air inhalation. The median dermal exposure on hand wipes was 0.32 ng·kg bw(-1)·day(-1) (IQR

  14. Evaluation of dust-related health hazards associated with air coring at G-Tunnel, Nevada Test Site

    SciTech Connect

    Skaggs, B.J.; Ortiz, L.W.; Burton, D.J.; Isom, B.L.; Vigil, E.A.

    1991-03-01

    The Yucca Mountain Project was established to evaluate the potential for storing high-level radioactive wastes in geologic formations. Hydrologists recommended that drilling or coring in support of characterization tests be performed dry. Dry drilling, or air coring, presents a concern about health protection for the drilling personnel. The rock generally has a high silica content, and natural zeolites are abundant. Some zeolites are fibrous, leading to concerns that inhalation may result in asbestos-like lung diseases. An industrial hygiene study (IH) was conducted as part of an air coring technical feasibility test. The IH study found the potential for exposures to airborne silica and nuisance dusts to be within regulatory requirements and determined the commercial dust control equipment monitored to be effective when used in conjunction with a good area ventilation system and sound IH practices. Fibrous zeolites were not detected. Recommendations for the Yucca Mountain studies are (1) dust collection and control equipment equivalent or superior to that monitored must be used for any dry drilling activity and must be used with good general dilution ventilation and local exhaust ventilation provided on major emission sources; (2) good industrial hygiene work practices must be implemented, including monitoring any area where zeolitic fibers are suspect; and (3) a study should be conducted to determine the biological effects of the fibrous zeolite, mordenite. 25 refs., 17 figs., 14 tabs.

  15. The influence of the sand-dust environment on air-gap breakdown discharge characteristics of the plate-to-plate electrode

    NASA Astrophysics Data System (ADS)

    He, Bo; Zhang, Gang; Chen, Bangfa; Gao, Naikui; Li, Yaozhong; Peng, Zongren; Jin, Haiyun

    2010-03-01

    The experiments of plane-plane gap discharge was carried out in an environment of artificial sandstorm. By comparing and analyzing the differences in gap breakdown voltage between the sand & dust environment and clean air, some problems were investigated, such as effects of wind speed and particle concentration on the breakdown voltage, differences of gap discharge characteristics between the dust & sand medium and the clean air medium. The results showed that compared with the clean air environment, the dust & sand environment had a decreased gap breakdown voltage. The longer the gap distance, the greater the voltage drop; the breakdown voltage decreased with the increase of particle concentration in flow. With the increase of wind speed, the breakdown voltage decreased at the beginning and rose afterwards. The results of the paper may helpful for further research regarding the unidentified flashover and external insulation characteristics of the HV power grid in the dust & sand environment.

  16. The Impact of African Dust on PM10 Air Quality in the Caribbean Basin

    NASA Astrophysics Data System (ADS)

    Prospero, J. M.

    2015-12-01

    Decades of aerosol measurements on Barbados and Miami have yielded a broad picture of African mineral dust transport to the Caribbean Basin. These measurements show that in summer the aerosol mass is often dominated by dust. At such times over 90% of the dust mass is comprised of particles less than 10 μm aerodynamic diameter and thus fits the EPA criteria for PM10. A number of sites in the Caribbean monitor PM10 using the same instrumentation commonly deployed in European and United States networks. By comparing data from individual islands that have multiple monitoring sites (e.g., Puerto Rico, Martinique, Guadeloupe), it is shown that during dust events PM10 concentrations track very closely and that local sources have a minor impact on PM10 above about 15 to 20 μg m-3. Moreover the PM10 measurements are coherent with the movement of dust clouds over the islands as observed by satellites. In this way dust movement can be tracked at PM10 sites along the Gulf and southeast coasts of the United States. To assess the specific impact of African dust on PM10 in the region, I compare the daily records of dust measurements at Miami and Barbados with concurrent measurements made at proximate PM10 sites. I then use these relationships and the long term dust measurements at Barbados and Miami to assess the long-term variability of PM10 across the region. At Barbados the record goes back 50 years and provides a basis of assessing the effects of climate variability on PM10 transport. This study shows that there is great variability on scales ranging from daily to decadal. The impact of the droughts in the 1970s and 1980s was particularly significant. Across the Caribbean, the rates of exceedances of the WHO PM10 guideline is comparable to those observed in many major urban areas in Europe and the US. The dominance of dust in large PM10 events and the absence of major pollution sources on many islands offers the opportunity to study the health impacts of desert dust in

  17. Survey of air-cure experience on dust control system design for PRB coal

    SciTech Connect

    Harris, M.R.

    1998-07-01

    This paper describes major changes required in features for coal dust control systems when existing coal fired power plants switch to PRB (Powder River Basin) coal. It encompasses all transfer points within the coal handling system from receiving to the plant bunkers or silos. It provides a comparison of bituminous and PRB coal from a dust collection aspect, the major features required for reliability and safety and the reasons for implementation.

  18. A new exposure metric for traffic-related air pollution? An analysis of determinants of hopanes in settled indoor house dust

    PubMed Central

    2013-01-01

    Background Exposure to traffic-related air pollution (TRAP) can adversely impact health but epidemiologic studies are limited in their abilities to assess long-term exposures and incorporate variability in indoor pollutant infiltration. Methods In order to examine settled house dust levels of hopanes, engine lubricating oil byproducts found in vehicle exhaust, as a novel TRAP exposure measure, dust samples were collected from 171 homes in five Canadian cities and analyzed by gas chromatography–mass spectrometry. To evaluate source contributions, the relative abundance of the highest concentration hopane monomer in house dust was compared to that in outdoor air. Geographic variables related to TRAP emissions and outdoor NO2 concentrations from city-specific TRAP land use regression (LUR) models were calculated at each georeferenced residence location and assessed as predictors of variability in dust hopanes. Results Hopanes relative abundance in house dust and ambient air were significantly correlated (Pearson’s r=0.48, p<0.05), suggesting that dust hopanes likely result from traffic emissions. The proportion of variance in dust hopanes concentrations explained by LUR NO2 was less than 10% in Vancouver, Winnipeg and Toronto while the correlations in Edmonton and Windsor explained 20 to 40% of the variance. Modeling with household factors such as air conditioning and shoe removal along with geographic predictors related to TRAP generally increased the proportion of explained variability (10-80%) in measured indoor hopanes dust levels. Conclusions Hopanes can consistently be detected in house dust and may be a useful tracer of TRAP exposure if determinants of their spatiotemporal variability are well-characterized, and when home-specific factors are considered. PMID:23782977

  19. Observation of Dust and Smoke Plume Transport and Impact on Remote Sensing of Air Quality in New York City

    NASA Astrophysics Data System (ADS)

    Moshary, F.; Wu, Y.; Han, Z. T.; Nazmi, C.; Gross, B.

    2015-12-01

    Long-range transport of aloft aerosol plumes affects both air quality and climate on regional and continental scales. Asian dust impacts on the western US and Canada have been extensively analyzed, yet such quantitative demonstrations are not well documented in the northeastern US. Similarly, episodes of continental transport of smoke plumes from forest fires in western US and Canada impact visibility and air quality in the US east coast. In this study, we present the synergistic observation of transported dust and smoke aerosol plumes in New York City (NYC, 40.821ºN, 73.949ºW), using a combination of a ground-based multiple-wavelength lidar, a CIMEL sunphotometer/radiometer, satellite sensors such as CALIOP and MODIS/VIIRS, and NAAPS aerosol forecast model. We show case studies of trans-Pacific Asian dust transport to the northeast US driven by the strong western or polar jets. The potential impact of the plumes on the local air quality is indicated by the plumes mixing down into boundary layer and the coincident increase of the ground PM measurement. Using multi-year lidar and sunphotometer observations, range-resolved monthly occurrence frequency of aloft aerosol plumes and modification of local aerosol optical properties are presented. The transport paths and the optical properties of aerosol for each clustered path are characterized. We further demonstrate the impact of these aloft plumes on the surface PM2.5 estimates from MODIS and VIIRS derived aerosol optical depth (AOD), and observe that when the aloft plumes-layer AODs are filtered out using lidar, the correlation between AOD-PM2.5 is much improved.

  20. Dimethyl sulfide air-sea fluxes and biogenic sulfur as a source of new aerosols in the Arctic fall

    NASA Astrophysics Data System (ADS)

    Rempillo, Ofelia; Seguin, Alison Michelle; Norman, Ann-Lise; Scarratt, Michael; Michaud, Sonia; Chang, Rachel; Sjostedt, Steve; Abbatt, Jon; Else, Brent; Papakyriakou, Tim; Sharma, Sangeeta; Grasby, Steve; Levasseur, Maurice

    2011-09-01

    Dimethyl sulfide (DMS) and its oxidation products, which have been proposed to provide a climate feedback mechanism by affecting aerosol and cloud radiative properties, were measured on board the Canadian Coast Guard ship Amundsen in sampling campaigns in the Arctic in the fall of 2007 and 2008. DMS flux was calculated based on the surface water measurements and yielded 0.1-2.6 μmol m-2 d-1 along the Northwest Passage in 2007 and 0.2-1.3 μmol m-2 d-1 along Baffin Bay in 2008. DMS oxidation products, sulfur dioxide (SO2), methane sulfonic acid (MSA), and sulfate in aerosols were also measured. The amounts of biogenic SO2 and sulfate were approximated using stable isotope apportionment techniques. Calculating the threshold amount of SO2 needed for significant new particle formation from the formulation by Pirjola et al. (1999), the study suggests that instances of elevated biogenic SO2 concentrations (between 8 and 9 September 2008) derived using conservative assumptions may have been sufficient to form new aerosols in clean air conditions in the Arctic region.

  1. Solar-Panel Dust Accumulation and Cleanings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Air-fall dust accumulates on the solar panels of NASA's Mars Exploration Rovers, reducing the amount of sunlight reaching the solar arrays. Pre-launch models predicted steady dust accumulation. However, the rovers have been blessed with occasional wind events that clear significant amounts of dust from the solar panels.

    This graph shows the effects of those panel-cleaning events on the amount of electricity generated by Spirit's solar panels. The horizontal scale is the number of Martian days (sols) after Spirit's Jan. 4, 2005, (Universal Time) landing on Mars. The vertical scale indicates output from the rover's solar panels as a fraction of the amount produced when the clean panels first opened. Note that the gradual declines are interrupted by occasional sharp increases, such as a dust-cleaning event on sol 420.

  2. Intercontinental transport of pollution and dust aerosols: implications for regional air quality

    NASA Astrophysics Data System (ADS)

    Chin, Mian; Diehl, T.; Ginoux, P.; Malm, W.

    2007-06-01

    We use the global model GOCART to examine the impact of pollution and dust aerosols emitted from their major sources on surface fine particulate matter concentrations at regional and hemispheric scales. Focusing on the North America region in 2001, we use measurements from the IMPROVE network in the United States to evaluate the model-simulated surface concentrations of the "reconstructed fine mass" (RCFM) and its components of ammonium sulfate, black carbon (BC), organic matter (OM), and fine mode dust. We then quantify the RCFM budget in terms of the RCFM composition, type, and origin to find that in the eastern U.S., ammonium sulfate is the dominant RCFM component (~60%) whereas in the western U.S., dust and OM are just as important as sulfate but have considerable seasonal variations, especially in the NW. On an annual average, North America regional pollution accounts for nearly 30-40% of the surface RCFM in the western U.S., and for a much higher proportion of 65-70% in the eastern U.S. By contrast, pollution from outside of North America contributes to just 2-6% (~0.2 μg m-3) of the total RCFM over the U.S. on an annual average. In comparison, long-range transport of dust is more efficient than that of pollution, which brings 3 to 4 times more fine particles to the U.S. (0.5-0.8 μg m-3 on an annual average) with a maximum influence in spring and over the NW. Of the major pollution regions, Europe has the largest potential to affect the surface aerosol concentrations in other continents due to its shorter distance from receptor continents and its larger fraction of sulfate-producing precursor gas in the outflow. With the IPCC emission scenario for the year 2000, we find that European emissions increase levels of ammonium sulfate by 1-5 μg m-3 over the surface of northern Africa and western Asia, and its contribution to eastern Asia (≥0.2 μg m-3) is twice as much as the Asian contribution to North America. Asia and North America pollution emissions exert

  3. Contribution of Saharan dust in an integrated air quality system and its on-line assessment

    NASA Astrophysics Data System (ADS)

    Jiménez-Guerrero, Pedro; Pérez, Carlos; Jorba, Oriol; Baldasano, José M.

    2008-02-01

    Nowadays none of the operational daily forecasts in Europe includes the influence of Saharan dust on a non-climatic basis. In order to account for this, the BSC-CNS currently operates daily photochemical forecasts in the Iberian Peninsula with MM5-EMEP-CMAQ modelling system and Saharan dust forecasts over Southern Europe with Eta/DREAM. The necessity of coupling both modelling systems is addressed by the study of a long summer episode combining regional re-circulations and Saharan dust covering from June 19 to July 12, 2006. As a first approach, the natural dust contribution from Eta/DREAM is added on-line to the anthropogenic output of CMAQ. The performance of the model has been quantitatively evaluated with discrete and categorical (skill scores) statistics by a fully operational on-line comparison of the first-layer simulations results of CMAQ and CMAQ+DREAM and the values measured in two different stations located in the Mediterranean part of the domain. The results indicate a remarkable improvement in the discrete and skill-scores evaluation (accuracy, critical success index and probability of detection) of PM10 exceedances set in regulations when using CMAQ+DREAM compared to CMAQ- or DREAM-alone simulations.

  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. PMID:6246327

  5. Anthropogenic Air Pollution Observed Near Dust Source Regions in Northwestern China During Springtime 2008

    NASA Technical Reports Server (NTRS)

    Li, Can; Tsay, Si-Chee; Fu, Joshua S.; Dickerson, Russell R.; Ji, Qiang; Bell, Shaun W.; Gao, Yang; Zhang, Wu; Huang, Jianping; Li, Zhanqing; Chen, Hongbin

    2010-01-01

    Trace gases and aerosols were measured in Zhangye (39.082degN, 100.276degE, 1460 m a.s. 1.), a rural site near the Gobi deserts in northwestern China during spring 2008. Primary trace gases (CO:265 ppb; SO2:3.4 ppb; NO(*y): 4.2 ppb; hereafter results given as means of hourly data) in the area were lower than in eastern China, but still indicative of marked anthropogenic emissions. Sizable aerosol mass concentration (153 micro-g/cu m) and light scattering (159/Mm at 500 nm) were largely attributable to dust emissions, and aerosol light absorption (10.3/Mm at 500 nm) was dominated by anthropogenic pollution. Distinct diurnal variations in meteorology and pollution were induced by the local valley terrain. Strong daytime northwest valley wind cleaned out pollution and was replaced by southeast mountain wind that allowed pollutants to build up overnight. In the afternoon, aerosols had single scattering albedo (SSA, 500 mn) of 0.95 and were mainly of supermicron particles, presumably dust, while at night smaller particles and SSA of 0.89-0.91 were related to Pollution. The diverse local emission sources were characterized: the CO/SO2, CO/NO(y), NO(y)/SO2 (by moles), and BC/CO (by mass) ratios for small point sources such as factories were 24.6-54.2, 25.8-35.9, 0.79-1.31, and 4.1-6.1 x 10(exp -3), respectively, compared to the corresponding inventory ratios of 43.7-71.9, 23.7-25.7, 1.84-2.79, and 3.4-4.0 x 10(exp -3) for the industrial sector in the area. The mixing between dust and pollution can be ubiquitous in this region. During a dust storm shown as an example, pollutants were observed to mix with dust, causing discernible changes in both SSA and aerosol size distribution. Further interaction between dust and pollutants during transport may modify the properties of dust particles that are critical for their large-scale impact on radiation, clouds, and global biogeochemical cycles.

  6. Anthropogenic air pollution observed near dust source regions in northwestern China during springtime 2008

    NASA Astrophysics Data System (ADS)

    Li, Can; Tsay, Si-Chee; Fu, Joshua S.; Dickerson, Russell R.; Ji, Qiang; Bell, Shaun W.; Gao, Yang; Zhang, Wu; Huang, Jianping; Li, Zhanqing; Chen, Hongbin

    2010-04-01

    Trace gases and aerosols were measured in Zhangye (39.082°N, 100.276°E, 1460 m a.s.l.), a rural site near the Gobi deserts in northwestern China during spring 2008. Primary trace gases (CO: 265 ppb; SO2: 3.4 ppb; NOy*: 4.2 ppb; hereafter results given as means of hourly data) in the area were lower than in eastern China, but still indicative of marked anthropogenic emissions. Sizable aerosol mass concentration (153 μg/m3) and light scattering (159 Mm-1 at 500 nm) were largely attributable to dust emissions, and aerosol light absorption (10.3 Mm-1 at 500 nm) was dominated by anthropogenic pollution. Distinct diurnal variations in meteorology and pollution were induced by the local valley terrain. Strong daytime northwest valley wind cleaned out pollution and was replaced by southeast mountain wind that allowed pollutants to build up overnight. In the afternoon, aerosols had single scattering albedo (SSA, 500 nm) of 0.95 and were mainly of supermicron particles, presumably dust, while at night smaller particles and SSA of 0.89-0.91 were related to pollution. The diverse local emission sources were characterized: the CO/SO2, CO/NOy, NOy/SO2 (by moles), and BC/CO (by mass) ratios for small point sources such as factories were 24.6-54.2, 25.8-35.9, 0.79-1.31, and 4.1-6.1 × 10-3, respectively, compared to the corresponding inventory ratios of 43.7-71.9, 23.7-25.7, 1.84-2.79, and 3.4-4.0 × 10-3 for the industrial sector in the area. The mixing between dust and pollution can be ubiquitous in this region. During a dust storm shown as an example, pollutants were observed to mix with dust, causing discernible changes in both SSA and aerosol size distribution. Further interaction between dust and pollutants during transport may modify the properties of dust particles that are critical for their large-scale impact on radiation, clouds, and global biogeochemical cycles.

  7. Air-dust-borne associations of phototrophic and hydrocarbon-utilizing microorganisms: promising consortia in volatile hydrocarbon bioremediation.

    PubMed

    Al-Bader, Dhia; Eliyas, Mohamed; Rayan, Rihab; Radwan, Samir

    2012-11-01

    Aquatic and terrestrial associations of phototrophic and heterotrophic microorganisms active in hydrocarbon bioremediation have been described earlier. The question arises: do similar consortia also occur in the atmosphere? Dust samples at the height of 15 m were collected from Kuwait City air, and analyzed microbiologically for phototrophic and heterotrophic hydrocarbon-utilizing microorganisms, which were subsequently characterized according to their 16S rRNA gene sequences. The hydrocarbon utilization potential of the heterotrophs alone, and in association with the phototrophic partners, was measured quantitatively. The chlorophyte Gloeotila sp. and the two cyanobacteria Nostoc commune and Leptolyngbya thermalis were found associated with dust, and (for comparison) the cynobacteria Leptolyngbya sp. and Acaryochloris sp. were isolated from coastal water. All phototrophic cultures harbored oil vapor-utilizing bacteria in the magnitude of 10(5) g(-1). Each phototrophic culture had its unique oil-utilizing bacteria; however, the bacterial composition in Leptolyngbya cultures from air and water was similar. The hydrocarbon-utilizing bacteria were affiliated with Acinetobacter sp., Aeromonas caviae, Alcanivorax jadensis, Bacillus asahii, Bacillus pumilus, Marinobacter aquaeolei, Paenibacillus sp., and Stenotrophomonas maltophilia. The nonaxenic cultures, when used as inocula in batch cultures, attenuated crude oil in light and dark, and in the presence of antibiotics and absence of nitrogenous compounds. Aqueous and diethyl ether extracts from the phototrophic cultures enhanced the growth of the pertinent oil-utilizing bacteria in batch cultures, with oil vapor as a sole carbon source. It was concluded that the airborne microbial associations may be effective in bioremediating atmospheric hydrocarbon pollutants in situ. Like the aquatic and terrestrial habitats, the atmosphere contains dust-borne associations of phototrophic and heterotrophic hydrocarbon

  8. Polychlorinated dibenzofurans and dibenzo-p-dioxins in subsurface soil, superficial dust, and air extracts from a contaminated landfill.

    PubMed

    Hansen, L G; O'Keefe, P W

    1996-08-01

    Extracts of soil, dust and air from a National Priorities List Landfill have been found to contain distinct profiles of polychlorinated biphenyls (PCBs). The different extracts show subtle differences in toxicities and the soil extract has been shown to cause both Ah receptor mediated effects and Ah receptor independent effects in immature female rats. Evidence of open burning at the site dictated quantitation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) for a more accurate tabulation of dioxin equivalencies. High volume air sampling on XAD-2 resin cartridges captured trace amounts of PCDFs and no detectable PCDDs. Acetone:Hexane (1:1) extracts of soil and dust contained 762 microg/ml and 250 microg/ml PCDFs, respectively, and less than 10% as much PCDD. Subsequent benzene:methylene chloride (1:1) extracts were enriched in coplanar compounds relative to total PCBs. PCDF:PCB ratios in all extracts were higher than in the rice oils contaminated with heated PCBs in the Yusho and Yu-Cheng incidents. No 2,3,7,8-TCDD was detected, and total PCB+PCDD+PCDF toxic equivalencies were dominated by the high proportions of PCDFs. PMID:8785012

  9. Characterizing a persistent Asian dust transport event: Optical properties and impact on air quality through the ground-based and satellite measurements over Nanjing, China

    NASA Astrophysics Data System (ADS)

    Han, Yong; Wu, Yonghua; Wang, Tijian; Xie, Chenbo; Zhao, Kun; Zhuang, Bingliang; Li, Shu

    2015-08-01

    The optical properties, time-height distribution and impact on the local air quality from a heavy Asian dust transport episode are investigated with a synergistic ground-based, satellite sensors and transport model on 1 May, 2011 at Nanjing (32.05° N, 118.78° E, and 94 m ASL) in southeast China. Two dust layers located in the planetary-boundary-layer (PBL, <2.5 km) and free troposphere (3-6 km) are observed by a Polarization Raman-Mie Lidar, with the lower one originating from the Gobi deserts and the higher one from the Taklimakan deserts. The dust aerosol layer shows the depolarization ratios at 0.1-0.2 and strong extinction coefficients of 1.0 km-1 at 532-nm, while the extinction-to-backscatter ratios (e.g. lidar ratios) of dust are 47.3-55 sr below 2.5 km. During this dust intrusion period, the aerosol optical depths (AOD) dramatically increase from 0.7 to 1.6 at 500-nm whereas the Angstrom exponents decrease from 1.2 to 0.2. Meanwhile, surface PM10 and PM2.5 concentrations show a significant and coincident increase with the peak value reaching 767 μg/m3 and 222 μg/m3, respectively, indicating the mixture of dust with the anthropogenic aerosols. Regional influences of the transported dust in east China are further illustrated by the AERONET-sunphotometer at Taihu and Xianghe sites (downwind and upwind from Nanjing), satellites MODIS, CALIPSO and model products. Furthermore, the model product of dust profile and surface concentration are evaluated with the ground-based and CALISPO observation. The results indicate the model is capable of simulating the right timing of dust transport event and most loading below 3-km altitude; normalization of model dust with the PM10 near the Gobi deserts improves modeling surface dust concentration in Nanjing.

  10. Variations in welding characteristics within the Plinian air-fall deposit of the Middle Pumice eruption, Santorini, Greece

    NASA Astrophysics Data System (ADS)

    Boyce, Julie Ann; Gertisser, Ralf

    2012-04-01

    The welded Plinian air-fall deposit of the Middle Pumice A (MP-A) eruption, Santorini, Greece (144.6 ka), was analysed in order to document welding characteristics and determine the factors that control welding due to the sintering of hot ash- to block-sized pyroclasts. There are vertical and lateral variations in welding intensity, with welding increasing upwards within deposit sections and decreasing laterally away from the source. Four welding grades are distinguished: a = densely-welded, b = slightly-welded, c = tack-welded, and d = non-welded. Lateral welding zones are defined by the highest welding grade observed: zone A = densely-welded (< 0.25 km from the source); zone B = slightly-welded (0.25-1.26 km); zone C = tack-welded (1.26-3.7 km), and zone D = non-welded (> 3.7 km). Pumice density increases (and porosity decreases) with welding, with the most densely-welded part having a density of 2290 kg m- 3 and a porosity of 5%. Distal, non-welded pumices have a density of 370 kg m- 3 and porosities of > 75%. Clast oblateness varies from 0.79 in the densely-welded proximal deposit sections to 0.54 in the distal, non-welded deposits in southern Thera. Strain, determined using the Rf/ϕ method, indicates that the deposit is moderately flattened but relatively undeformed. The MP-A deposit is dacitic to andesitic in composition, becoming more mafic with stratigraphic height, where the degree of welding is highest. Welding is controlled by geochemical variations, compactional load and local variations in accumulation rate and clast sizes.

  11. Testing an advanced satellite technique for dust detection as a decision support system for the air quality assessment

    NASA Astrophysics Data System (ADS)

    Falconieri, Alfredo; Filizzola, Carolina; Femiano, Rossella; Marchese, Francesco; Sannazzaro, Filomena; Pergola, Nicola; Tramutoli, Valerio; Di Muro, Ersilia; Divietri, Mariella; Crisci, Anna Maria; Lovallo, Michele; Mangiamele, Lucia; Vaccaro, Maria Pia; Palma, Achille

    2014-05-01

    In order to correctly apply the European directive for air quality (2008/50/CE), local Authorities are often requested to discriminate the possible origin (natural/anthropic) of anomalous concentration of pollutants in the air (art.20 Directive 2008/50/CE). In this framework, it's been focused on PM10 and PM2,5 concentrations and sources. In fact, depending on their origin, appropriate counter-measures can be taken devoted to prevent their production (e.g. by traffic restriction) or simply to reduce their impact on citizen health (e.g. information campaigns). In this context suitable satellite techniques can be used in order to identify natural sources (particularly Saharan dust, but also volcanic ash or forest fire smoke) that can be responsible of over-threshold concentration of PM10/2,5 in populated areas. In the framework of the NIBS (Networking and Internationalization of Basilicata Space Technologies) project, funded by the Basilicata Region within the ERDF 2007-2013 program, the School of Engineering of University of Basilicata, the Institute of Methodologies for Environmental Analysis of National Research Council (IMAA-CNR) and the Regional Agency for the Protection of the Environment of Basilicata Region (ARPAB) have started a collaboration devoted to assess the potential of the use of advanced satellite techniques for Saharan dust events identification to support ARPAB activities related to the application of the European directive for air quality (2008/50/CE) in Basilicata region. In such a joint activity, the Robust Satellite Technique (RST) approach has been assessed and tested as a decision support system for monitoring and evaluating air quality at local and regional level. In particular, RST-DUST products, derived by processing high temporal resolution data provided by SEVIRI (Spinning Enhanced Visible and Infrared Imager) sensor on board Meteosat Second Generation platforms, have been analysed together with PM10 measurements performed by the ground

  12. Escherichia coli in settled-dust and air samples collected in residential environments in Mexico City.

    PubMed Central

    Rosas, I; Salinas, E; Yela, A; Calva, E; Eslava, C; Cravioto, A

    1997-01-01

    Escherichia coli, an important indicator of the presence of fecal material, was isolated from indoor and outdoor environments in Mexico City. The heterogeneity of E. coli was represented by 89 serotypes, most of them coming from settled-dust indoor samples; 21% of them presented antibiotic multiresistance. The numbers of plasmids were higher among the antibiotic-resistant strains. The results of this study suggest that intestinal infections produced by environmental strains could be of more epidemiological impact than previously thought. PMID:9327575

  13. 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. PMID:26491105

  14. Model development of dust emission and heterogeneous chemistry within the Community Multiscale Air Quality modeling system and its application over East Asia

    NASA Astrophysics Data System (ADS)

    Dong, X.; Fu, J. S.; Huang, K.; Tong, D.

    2015-12-01

    The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust aerosols. The default parameterization of threshold friction velocity constants in the CMAQ are revised to avoid double counting of the impact of soil moisture based on the re-analysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is implemented to simulate the reactions involving dust aerosol. The improved dust module in the CMAQ was applied over East Asia for March and April from 2006 to 2010. Evaluation against observations has demonstrated that simulation bias of PM10 and aerosol optical depth (AOD) is reduced from -55.42 and -31.97 % in the original CMAQ to -16.05 and -22.1 % in the revised CMAQ, respectively. Comparison with observations at the nearby Gobi stations of Duolun and Yulin indicates that applying a source-dependent profile helps reduce simulation bias for trace metals. Implementing heterogeneous chemistry is also found to result in better agreement with observations for sulfur dioxide (SO2), sulfate (SO42-), nitric acid (HNO3), nitrous oxides (NOx), and nitrate (NO3-). Investigation of a severe dust storm episode from 19 to 21 March 2010 suggests that the revised CMAQ is capable of capturing the spatial distribution and temporal variations of dust aerosols. Model evaluation indicates potential uncertainties within the excessive soil moisture fraction used by meteorological simulation. The mass contribution of fine mode aerosol in dust emission may be underestimated by 50 %. The revised revised CMAQ provides a useful tool for future studies to investigate the emission, transport, and impact of wind-blown dust over East

  15. Retrieving dust aerosols properties (optical depth and altitude) from very high resolution infrared sounders : from AIRS to IASI.

    NASA Astrophysics Data System (ADS)

    Peyridieu, S.; Chédin, A.; Capelle, V.; Pierangelo, C.; Lamquin, N.; Armante, R.

    2009-04-01

    Observation from space, being global and quasi-continuous, is a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the thermal infrared domain still remains marginal. However, knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing. Infrared remote sensing provides a way to retrieve other aerosol characteristics, including their mean altitude. Moreover, observations are possible at night and day, over ocean and over land. In this context, six years (2003-2008) of the 2nd generation vertical sounder AIRS observations have been processed over the tropical belt (30°N-30°S). Aerosol properties (10 µm infrared optical depth and mean layer altitude) are retrieved using a Look-Up Table (LUT) approach. The forward radiative transfer model 4A (Automatized Atmospheric Absorption Atlas) coupled with the DISORT algorithm accounting for atmospheric diffusion is used to feed the LUTs with simulations of the brightness temperatures of AIRS channels selected for their sensitivity to dust aerosols. LUTs degrees of freedom are : instrument viewing angle, surface pressure and surface emissivity, a parameter particularly important for dust retrieval over bright surfaces, such as deserts. AODs (resp. altitude) are sampled over the range 0.0-0.8 (resp. 0-5800 m). The retrieval algorithm follows two main steps : (i) retrieval of the atmospheric situation observed (temperature and water vapour profiles) ; (ii) retrieval of aerosol properties. Results have been compared to instruments commonly used in aerosol studies and also part of the Aqua Train : MODIS/Aqua and CALIOP/CALIPSO. The agreement obtained from these comparisons is quite satisfactory, demonstrating that our algorithm effectively allows the simultaneous retrieval of dust AOD

  16. Contamination of indoor dust and air by polychlorinated biphenyls and brominated flame retardants and relevance of non-dietary exposure in Vietnamese informal e-waste recycling sites.

    PubMed

    Tue, Nguyen Minh; Takahashi, Shin; Suzuki, Go; Isobe, Tomohiko; Viet, Pham Hung; Kobara, Yuso; Seike, Nobuyasu; Zhang, Gan; Sudaryanto, Agus; Tanabe, Shinsuke

    2013-01-01

    This study investigated the occurrence of polychlorinated biphenyls (PCBs), and several additive brominated flame retardants (BFRs) in indoor dust and air from two Vietnamese informal e-waste recycling sites (EWRSs) and an urban site in order to assess the relevance of these media for human exposure. The levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) in settled house dust from the EWRSs (130-12,000, 5.4-400, 5.2-620 and 31-1400 ng g(-1), respectively) were significantly higher than in urban house dust but the levels of PCBs (4.8-320 ng g(-1)) were not higher. The levels of PCBs and PBDEs in air at e-waste recycling houses (1000-1800 and 620-720 pg m(-3), respectively), determined using passive sampling, were also higher compared with non-e-waste houses. The composition of BFRs in EWRS samples suggests the influence from high-temperature processes and occurrence of waste materials containing older BFR formulations. Results of daily intake estimation for e-waste recycling workers are in good agreement with the accumulation patterns previously observed in human milk and indicate that dust ingestion contributes a large portion of the PBDE intake (60%-88%), and air inhalation to the low-chlorinated PCB intake (>80% for triCBs) due to their high levels in dust and air, respectively. Further investigation of both indoor dust and air as the exposure media for other e-waste recycling-related contaminants and assessment of health risk associated with exposure to these contaminant mixtures is necessary. PMID:23228866

  17. Not Just a Fall Tree

    ERIC Educational Resources Information Center

    Miller-Hewes, Kathy A.

    2004-01-01

    Trees burst with color in the northern states. Autumn leaves dust the ground. Painting the fall landscape is nothing new. Teachers have been doing it in classrooms for decades. The approach, however, can make the difference between whether the fall landscape is simply painting for fun, or a real learning experience. Students learn best when they…

  18. Model development of dust emission and heterogeneous chemistry within the Community Multiscale Air Quality modeling system and its application over East Asia

    NASA Astrophysics Data System (ADS)

    Dong, Xinyi; Fu, Joshua S.; Huang, Kan; Tong, Daniel; Zhuang, Guoshun

    2016-07-01

    The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust. The default parameterization of initial threshold friction velocity constants are revised to correct the double counting of the impact of soil moisture in CMAQ by the reanalysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is also implemented. The improved dust module in the CMAQ is applied over East Asia for March and April from 2006 to 2010. The model evaluation result shows that the simulation bias of PM10 and aerosol optical depth (AOD) is reduced, respectively, from -55.42 and -31.97 % by the original CMAQ to -16.05 and -22.1 % by the revised CMAQ. Comparison with observations at the nearby Gobi stations of Duolun and Yulin indicates that applying a source-dependent profile helps reduce simulation bias for trace metals. Implementing heterogeneous chemistry also results in better agreement with observations for sulfur dioxide (SO2), sulfate (SO42-), nitric acid (HNO3), nitrous oxides (NOx), and nitrate (NO3-). The investigation of a severe dust storm episode from 19 to 21 March 2010 suggests that the revised CMAQ is capable of capturing the spatial distribution and temporal variation of dust. The model evaluation also indicates potential uncertainty within the excessive soil moisture used by meteorological simulation. The mass contribution of fine-mode particles in dust emission may be underestimated by 50 %. The revised CMAQ model provides a useful tool for future studies to investigate the emission, transport, and impact of wind-blown dust over East Asia and elsewhere.

  19. The Use of OMPS Near Real Time Products in Volcanic Cloud Risk Mitigation and Smoke/Dust Air Quality Assessments

    NASA Astrophysics Data System (ADS)

    Seftor, C. J.; Krotkov, N. A.; McPeters, R. D.; Li, J. Y.; Durbin, P. B.

    2015-12-01

    Near real time (NRT) SO2 and aerosol index (AI) imagery from Aura's Ozone Monitoring Instrument (OMI) has proven invaluable in mitigating the risk posed to air traffic by SO2 and ash clouds from volcanic eruptions. The OMI products, generated as part of NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) NRT system and available through LANCE and both NOAA's NESDIS and ESA's Support to Aviation Control Service (SACS) portals, are used to monitor the current location of volcanic clouds and to provide input into Volcanic Ash (VA) advisory forecasts. NRT products have recently been developed using data from the Ozone Mapping and Profiler Suite onboard the Suomi NPP platform; they are currently being made available through the SACS portal and will shortly be incorporated into the LANCE NRT system. We will show examples of the use of OMPS NRT SO2 and AI imagery to monitor recent volcanic eruption events. We will also demonstrate the usefulness of OMPS AI imagery to detect and track dust storms and smoke from fires, and how this information can be used to forecast their impact on air quality in areas far removed from their source. Finally, we will show SO2 and AI imagery generated from our OMPS Direct Broadcast data to highlight the capability of our real time system.

  20. Hazards of explosives dusts

    NASA Astrophysics Data System (ADS)

    The Bureau of Mines has investigated the hazards of military explosives dispersed as dust clouds in a 20-L test chamber. For purposes of personnel safety, the spark ignitability of the explosives in the form of unconfined dust layers was also studied. The 20-L data show that most of the explosive dusts were capable of sustaining explosions as dust clouds dispersed in air and some dusts were even capable of sustaining explosions when dispersed in nitrogen. The finest sizes of explosive dusts were less reactive than the larger sizes; this is opposite to the particle size effect observed previously for the pure fuel dusts. The data for the explosive dusts were compared to those for pure fuel dusts.

  1. The Effect of Dust Storm on the Microbial Quality of Ambient Air in Sanandaj: A City Located in the West of Iran

    PubMed Central

    Nourmoradi, Heshmatollah; Moradnejadi, Kambiz; Moghadam, Fazel Mohammadi; Khosravi, Behdad; Hemati, Lida; Khoshniyat, Ramin; Kazembeigi, Farogh

    2015-01-01

    Background and Aims: The presence of pathogenic microorganisms in the dust storm can cause diseases such as Asthma, Pneumonia, and respiratory infections. The aim of this study was to determine the relationship between air-borne particles with airborne microorganisms in normal and dusty days in Sanandaj, a city located in the west of Iran. Materials and Methods: Air sampling was conducted during the normal and dusty days through Andersen single-stage impactor (28.3 L/min) for 2.5 min. Air particles concentration (PM10) was measured daily and microbial sampling was also conducted on every six days and on the dusty days. Finally, the data was analyzed by SPSS-16 (ANOVA and paired T-tests). Results: The concentration of airborne microorganisms (bacteria and fungi) was increased by an increase of the airborne particles. Particles concentration in May, June and July (twice per month) was more than of the standard value. The predominant species of bacteria and fungi during the occurrence of Dust storm was Bacillus spp. (56.2% of total bacteria) and Mycosporium spp. (28.6% of total fungi), respectively. Discussion and Conclusion: The results showed that the number of airborne microorganisms (bacteria and fungi) increased during the dust storm. Therefore, the microorganisms in the dust storm can cause biological harmful effects on human health. PMID:26153211

  2. Daily and hourly sourcing of metallic and mineral dust in urban air contaminated by traffic and coal-burning emissions

    NASA Astrophysics Data System (ADS)

    Moreno, T.; Karanasiou, A.; Amato, F.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.; Coz, E.; Artíñano, B.; Lumbreras, J.; Borge, R.; Boldo, E.; Linares, C.; Alastuey, A.; Querol, X.; Gibbons, W.

    2013-04-01

    A multi-analytical approach to chemical analysis of inhalable urban atmospheric particulate matter (PM), integrating particle induced X-ray emission, inductively coupled plasma mass spectrometry/atomic emission spectroscopy, chromatography and thermal-optical transmission methods, allows comparison between hourly (Streaker) and 24-h (High volume sampler) data and consequently improved PM chemical characterization and source identification. In a traffic hot spot monitoring site in Madrid (Spain) the hourly data reveal metallic emissions (Zn, Cu, Cr, Fe) and resuspended mineral dust (Ca, Al, Si) to be closely associated with traffic flow. These pollutants build up during the day, emphasizing evening rush hour peaks, but decrease (especially their coarser fraction PM2.5-10) after nocturnal road washing. Positive matrix factorization (PMF) analysis of a large Streaker database additionally reveals two other mineral dust components (siliceous and sodic), marine aerosol, and minor, transient events which we attribute to biomass burning (K-rich) and industrial (incinerator?) Zn, Pb plumes. Chemical data on 24-h filters allows the measurement of secondary inorganic compounds and carbon concentrations and offers PMF analysis based on a limited number of samples but using fuller range of trace elements which, in the case of Madrid, identifies the continuing minor presence of a coal combustion source traced by As, Se, Ge and Organic Carbon. This coal component is more evident in the city air after the change to the winter heating season in November. Trace element data also allow use of discrimination diagrams such as V/Rb vs. La/Ce and ternary plots to illustrate variations in atmospheric chemistry (such as the effect of Ce-emissions from catalytic converters), with Madrid being an example of a city with little industrial pollution, recently reduced coal emissions, but serious atmospheric contamination by traffic emissions.

  3. Elemental mercury (Hg(0)) in air and surface waters of the Yellow Sea during late spring and late fall 2012: concentration, spatial-temporal distribution and air/sea flux.

    PubMed

    Ci, Zhijia; Wang, Chunjie; Wang, Zhangwei; Zhang, Xiaoshan

    2015-01-01

    The Yellow Sea in East Asia receives great Hg input from regional emissions. However, Hg cycling in this marine system is poorly investigated. In late spring and late fall 2012, we determined gaseous elemental Hg (GEM or Hg(0)) in air and dissolved gaseous Hg (DGM, mainly Hg(0)) in surface waters to explore the spatial-temporal variations of Hg(0) and further to estimate the air/sea Hg(0) flux in the Yellow Sea. The results showed that the GEM concentrations in the two cruises were similar (spring: 1.86±0.40 ng m(-3); fall: 1.84±0.50 ng m(-3)) and presented similar spatial variation pattern with elevated concentrations along the coast of China and lower concentrations in the open ocean. The DGM concentrations of the two cruises were also similar with 27.0±6.8 pg L(-1) in the spring cruise and 28.2±9.0 pg L(-1) in the fall cruise and showed substantial spatial variation. The air/sea Hg(0) fluxes in the spring cruise and fall cruise were estimated to be 1.06±0.86 ng m(-2) h(-1) and 2.53±2.12 ng m(-2) h(-1), respectively. The combination of this study and our previous summer cruise showed that the summer cruise presented enhanced values of GEM, DGM and air/sea Hg(0) flux. The possible reason for this trend was that high solar radiation in summer promoted Hg(0) formation in seawater, and the high wind speed during the summer cruise significantly increased Hg(0) emission from sea surface to atmosphere and subsequently enhanced the GEM levels. PMID:24999267

  4. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  5. Preventing falls

    MedlinePlus

    ... worsened. Improving your vision will help reduce falls. Images ... for preventing falls in older people living in the community. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: ...

  6. 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).

  7. A trans-Pacific Asian dust episode and its impacts to air quality in the east coast of U.S.

    NASA Astrophysics Data System (ADS)

    Wu, Yonghua; Han, Zaw; Nazmi, Chowdhury; Gross, Barry; Moshary, Fred

    2015-04-01

    The transport of an intense trans-Pacific Asian dust episode to the Northeast United States (U.S.) is studied using a synergistic suite of observations and models including a ground-based lidar, AERONET-sunphotometer, satellite measurements and global aerosol transport model for New York City (40.821°N, 73.949°W). During the dust intrusion on March 17-19, 2010, the multi-wavelength lidar observations indicate dense dust plumes (∼80% of total column AOD) located between 3 and 9 km altitudes with the lower layer mixing toward the planetary boundary layer (PBL). The column AOD shows a significant increase from 0.08 to 0.38 at 532-nm while the Angstrom exponent indicates a decrease from 1.3 to 0.7. The linear particle depolarization ratio is estimated to be 0.1-0.15 and the single-scattering-albedo shows the dust-like spectral dependence with the value of 0.9-0.95 at 440-nm. The NOAA-NCEP reanalysis and HYSPLIT model indicate that this long-range transport is driven by the strong western jets and travels for 6 days to arrive the U.S. east coast versus the western and northern U.S. Both the NAAPS aerosol transport model and satellite CALIPSO observations for multiple orbits clearly illustrate the dust-dominated aerosol along the transport path. In addition, coincident increase of both particulate matter (PM) and fine soil concentrations indicate the potential impact of transported dust on the air quality that is found to be associated with a large area of sinking air along the U.S. east coast.

  8. Analysis of heat and mass transfer between air and falling film desiccant for different flow configurations in the presence of ultrafine particles

    NASA Astrophysics Data System (ADS)

    Ali, Ahmad A.

    This work focuses on the enhancement of heat and mass transfer between air and falling desiccant film for different flow channel configurations. Cu-Ultrafine particles are added to the desiccant film to investigate the enhancement in heat and mass transfer between air and desiccant film for dehumidification and cooling processes of the air and regeneration of desiccant film. A detailed comparative study between parallel and counter flow channels is performed using a parametric study to investigate the enhancements in dehumidification, cooling, and regeneration processes in terms of the pertinent parameters. The results reveal that the parallel flow arrangement provides better dehumidification and cooling for the air than the counter flow channel for a wide range of parameters. Next, the inclined parallel and counter flow configurations are investigated using an Alternating Direction Implicit (ADI) and successive over-relaxation methods to discretize the vorticity and stream-function equations, respectively. A parametric study is employed to investigate the inclination angle effects in enhancing the heat and mass transfer in terms of the controlling parameters. It is shown that inclination angle plays a significant role in enhancing the dehumidification, cooling, and regeneration processes. Finally, the enhancements in heat and mass transfer in cross flow channel between air and desiccant film is examined based on a parametric study to investigate the dehumidification and cooling processes of the air in terms of the pertinent controlling parameters. These parameters are air and desiccant Reynolds numbers, dimensions of the channel, volume fraction of Cu-ultrafine particles, and thermal dispersion effects. It is found that an increase in the Cu-volume fraction increases dehumidification and cooling capabilities and produce more stable Cu-desiccant film.

  9. Preventing Falls

    MedlinePlus

    ... from osteoporosis. Lower-body strength exercises and balance exercises can help you prevent falls and avoid the disability that may result from falling. Here are some fall prevention tips from Go4Life : l Have your eyes and hearing tested often. Always wear your glasses when you ...

  10. Levels, distributions and correlations of polybrominated diphenyl ethers in air and dust of household and workplace in Shanghai, China: implication for daily human exposure.

    PubMed

    Xu, Feng; Tang, Weibiao; Zhang, Wei; Liu, Lili; Lin, Kuangfei

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) were measured in air (TSP and PM2.5) and dust samples collected from 16 households and the corresponding workplaces of eight volunteer citizens in Shanghai, China. The PBDEs concentrations in the workplace air (mean: 281 ± 126 pg m(-3)) were over two times higher than those in the household (121 ± 44.0 pg m(-3)), while the mean levels of PBDEs in dust were 995 ± 547 and 544 ± 188 ng g(-1) for workplace and household, respectively. BDE209 was the most abundant congener in all samples. PBDEs appeared to be composed of mostly small particles. The C particle/C dust ratios of less brominated PBDEs in PM2.5 were higher than those in TSP, while the values were approximately constant for the more brominated PBDEs. A correlation analysis by network indicated different sources and behavior of the PBDE congeners. The results of a cluster analysis were displayed on a heat map that specified the source and abundance of each PBDE congener. The daily PBDE exposure via dust ingestion was the predominant part of the total intake and was more than 10 times higher than the intake via inhalation. PMID:26490892

  11. A global Mars dust composition refined by the Alpha-Particle X-ray Spectrometer in Gale Crater

    NASA Astrophysics Data System (ADS)

    Berger, Jeff A.; Schmidt, Mariek E.; Gellert, Ralf; Campbell, John L.; King, Penelope L.; Flemming, Roberta L.; Ming, Douglas W.; Clark, Benton C.; Pradler, Irina; VanBommel, Scott J. V.; Minitti, Michelle E.; Fairén, Alberto G.; Boyd, Nicholas I.; Thompson, Lucy M.; Perrett, Glynis M.; Elliott, Beverley E.; Desouza, Elstan

    2016-01-01

    Modern Martian dust is similar in composition to the global soil unit and bulk basaltic Mars crust, but it is enriched in S and Cl. The Alpha Particle X-ray Spectrometer (APXS) on the Mars Science Laboratory Curiosity rover analyzed air fall dust on the science observation tray (o-tray) in Gale Crater to determine dust oxide compositions. The o-tray dust has the highest concentrations of SO3 and Cl measured in Mars dust (SO3 8.3%; Cl 1.1 wt %). The molar S/Cl in the dust (3.35 ± 0.34) is consistent with previous studies of Martian dust and soils (S/Cl = 3.7 ± 0.7). Fe is also elevated ~25% over average Mars soils and the bulk crust. These enrichments link air fall dust with the S-, Cl-, and Fe-rich X-ray amorphous component of Gale Crater soil. Dust and soil have the same S/Cl, constraining the surface concentrations of S and Cl on a global scale.

  12. Dust Plume off Mauritania

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A thick plume of dust blew off the coast of Mauritania in western Africa on October 2, 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite observed the dust plume as it headed toward the southwest over the Atlantic Ocean. In this image, the dust varies in color from nearly white to medium tan. The dust plume is easier to see over the dark background of the ocean, but the plume stretches across the land surface to the east, as well. The dust plume's structure is clearest along the coastline, where relatively clear air pockets separate distinct puffs of dust. West of that, individual pillows of dust push together to form a more homogeneous plume. Near its southwest tip, the plume takes on yet another shape, with stripes of pale dust fanning out toward the northwest. Occasional tiny white clouds dot the sky overhead, but skies are otherwise clear.

  13. Dust collector

    SciTech Connect

    Nelson, R.T.

    1986-10-21

    This patent describes a dust collector comprising: (a) a housing having inlet means for receiving air to be cleaned; (b) a plurality of filter units within the housing; (c) a first centrifugal fan arranged for drawing air through the units for removing dust from the air; (d) a plurality of ducts each connected to a corresponding one of the units at one end and to the first fan at the other end to provide passages for air from the units to the first fan, the ducts through a portion of their length being arranged in side-by-side relationship; (e) a second centrifugal fan for providing reverse flow of air through the ducts to the units, the second fan providing a high volume of air at low pressure; (f) a transverse duct connected to the second fan and extending transversely of the portion of the plurality of ducts and adjacent thereto: (g) a plurality of openings providing communication between the transverse duct and each of the plurality of ducts; (i) rotatable means engaging the vanes for sequentially moving the vanes between the first and second positions.

  14. Simultaneous heat and mass transfer inside a vertical tube in evaporating a heated falling alcohols liquid film into a stream of dry air

    NASA Astrophysics Data System (ADS)

    Senhaji, S.; Feddaoui, M.; Mediouni, T.; Mir, A.

    2009-03-01

    A numerical study of the evaporation in mixed convection of a pure alcohol liquid film: ethanol and methanol was investigated. It is a turbulent liquid film falling on the internal face of a vertical tube. A laminar flow of dry air enters the vertical tube at constant temperature in the downward direction. The wall of the tube is subjected to a constant and uniform heat flux. The model solves the coupled parabolic governing equations in both phases including turbulent liquid film together with the boundary and interfacial conditions. The systems of equations obtained by using an implicit finite difference method are solved by TDMA method. A Van Driest model is adopted to simulate the turbulent liquid film flow. The influence of the inlet liquid flow, Reynolds number in the gas flow and the wall heat flux on the intensity of heat and mass transfers are examined. A comparison between the results obtained for studied alcohols and water in the same conditions is made.

  15. Principle Component Analysis of the Evolution of the Saharan Air Layer and Dust Transport: Comparisons between a Model Simulation and MODIS Retrievals

    NASA Technical Reports Server (NTRS)

    Wong, S.; Colarco, P. R.; Dessler, A.

    2006-01-01

    The onset and evolution of Saharan Air Layer (SAL) episodes during June-September 2002 are diagnosed by applying principal component analysis to the NCEP reanalysis temperature anomalies at 850 hPa, where the largest SAL-induced temperature anomalies are located. The first principal component (PC) represents the onset of SAL episodes, which are associated with large warm anomalies located at the west coast of Africa. The second PC represents two opposite phases of the evolution of the SAL. The positive phase of the second PC corresponds to the southwestward extension of the warm anomalies into the tropical-subtropical North Atlantic Ocean, and the negative phase corresponds to the northwestward extension into the subtropical to mid-latitude North Atlantic Ocean and the southwest Europe. A dust transport model (CARMA) and the MODIS retrievals are used to study the associated effects on dust distribution and deposition. The positive (negative) phase of the second PC corresponds to a strengthening (weakening) of the offshore flows in the lower troposphere around 10deg - 20degN, causing more (less) dust being transported along the tropical to subtropical North Atlantic Ocean. The variation of the offshore flow indicates that the subseasonal variation of African Easterly Jet is associated with the evolution of the SAL. Significant correlation is found between the second PC time series and the daily West African monsoon index, implying a dynamical linkage between West African monsoon and the evolution of the SAL and Saharan dust transport.

  16. 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)). PMID:24556227

  17. Dust aerosol optical depth and altitude retrieved from 7 years of infrared sounders observations (AIRS, IASI) and comparison with other aerosol datasets (MODIS, CALIOP, PARASOL)

    NASA Astrophysics Data System (ADS)

    Peyridieu, Sophie; Chédin, Alain; Tanré, Didier; Capelle, Virginie; Pierangelo, Clémence; Lamquin, Nicolas; Armante, Raymond

    2010-05-01

    Remote sensing of aerosol properties in the visible domain has been widely used for a better characterization of these particles and of their effect on solar radiation. On the opposite, remote sensing of aerosols in the thermal infrared domain still remains marginal. However, knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing. A key point of infrared remote sensing is its ability to retrieve aerosol optical depth as well as mean dust layer altitude, a variable required for measuring their impact on climate. Moreover, observations are possible night and day, over ocean and over land. Our algorithm is specifically designed to retrieve simultaneously coarse mode dust aerosol 10 µm optical depth (AOD) and mean layer altitude from high spectral resolution infrared sounders observations. Thanks to IASI higher spectral resolution, the selection of finer channels for aerosol detection allows an even more accurate determination of aerosol properties. In this context, results obtained from 7 years (2003-2010) of AIRS/Aqua and more than 2 years (2007-2010) of IASI/Metop observations have been compared to other aerosol sensors. Compared to MODIS/Aqua optical depth product, 10 µm dust optical depth shows a very good agreement, particularly for tropical Atlantic regions downwind of the Sahara during the dust season. Comparisons with PARASOL non-spherical coarse mode product allows explaining small differences observed far from the sources. Time series of the mean aerosol layer altitude are compared to the CALIOP Level-2 products starting June 2006. For regions located downwind of the Sahara, the comparison again shows a good agreement with a mean standard deviation between the two products of about 400 m over the period processed, demonstrating that our algorithm effectively allows retrieving accurate mean dust layer altitude. A 7-year global climatology of the aerosol 10 µm dust optical depth and of the

  18. Vertical variation of optical properties of mixed Asian dust/pollution plumes according to pathway of air mass transport over East Asia

    NASA Astrophysics Data System (ADS)

    Shin, S.-K.; Müller, D.; Lee, C.; Lee, K. H.; Shin, D.; Kim, Y. J.; Noh, Y. M.

    2015-06-01

    We use five years (2009-2013) of multiwavelength Raman lidar measurements at Gwangju, South Korea (35.10° N, 126.53° E) for the identification of changes of optical properties of East Asian dust depending on its transport path over China. Profiles of backscatter and extinction coefficients, lidar ratios, and backscatter-related Ångström exponents (wavelength pair 355/532 nm) were measured at Gwangju. Linear particle depolarization ratios were used to identify East Asian dust layers. We used backward trajectory modeling to identify the pathway and the vertical position of dust-laden air masses over China during long-range transport. Most cases of Asian dust events can be described by the emission of dust in desert areas and subsequent transport over highly polluted regions of China. The Asian dust plumes could be categorized into two classes according to the height above ground at which these plumes were transported: (case I) the dust layers passed over China at high altitude levels (> 3 km) until arrival over Gwangju, and (case II) the Asian dust layers were transported near the surface and within the lower troposphere (< 3 km) over industrialized areas before they arrived over Gwangju. We find that the optical characteristics of these mixed Asian dust layers over Gwangju differ depending on their vertical position above ground over China and the change of height above ground during transport. The mean linear particle depolarization ratio was 0.21 ± 0.06 (at 532 nm), the mean lidar ratios were 52 ± 7 sr at 355 nm and 53 ± 8 sr at 532 nm, and the mean Ångström exponent was 0.74 ± 0.31 for case I. In contrast, plumes transported at lower altitudes (case II) showed low depolarization ratios (0.13 ± 0.04 at 532 nm), and higher lidar ratio (63 ± 9 sr at 355 nm and 62 ± 8 sr at 532 nm) and Ångström exponents (0.98 ± 0.51). These numbers show that the optical characteristics of mixed Asian plumes are more similar to optical characteristics of urban

  19. Desert Dust Air Mass Mapping in the Western Sahara, using Particle Properties Derived from Space-based Multi-angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Fiebig, Marcus; Schladitz, Alexander; von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the SAhara Mineral dUst experiMent (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from Multi-angle Imaging SpectroRadiometer (MISR) observations, and to place the sub-orbital aerosol measurements into the satellite's larger regional context. On three moderately dusty days for which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 to 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR's ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape, and single-scattering albedo. For the three study days, the satellite observations (a) highlight regional gradients in the mix of dust and background spherical particles, (b) identify a dust plume most likely part of a density flow, and (c) show an air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometers away.

  20. Desert Dust Aerosol Air Mass Mapping in the Western Sahara, Using Particle Properties Derived from Space-Based Multi-Angle Imaging

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph; Petzold, Andreas; Wendisch, Manfred; Bierwirth, Eike; Dinter, Tilman; Esselborn, Michael; Fiebig, Marcus; Heese, Birgit; Knippertz, Peter; Mueller, Detlef; Schladitz, Alexander; Von Hoyningen-Huene, Wolfgang

    2008-01-01

    Coincident observations made over the Moroccan desert during the Sahara mineral dust experiment (SAMUM) 2006 field campaign are used both to validate aerosol amount and type retrieved from multi-angle imaging spectroradiometer (MISR) observations, and to place the suborbital aerosol measurements into the satellite s larger regional context. On three moderately dusty days during which coincident observations were made, MISR mid-visible aerosol optical thickness (AOT) agrees with field measurements point-by-point to within 0.05 0.1. This is about as well as can be expected given spatial sampling differences; the space-based observations capture AOT trends and variability over an extended region. The field data also validate MISR s ability to distinguish and to map aerosol air masses, from the combination of retrieved constraints on particle size, shape and single-scattering albedo. For the three study days, the satellite observations (1) highlight regional gradients in the mix of dust and background spherical particles, (2) identify a dust plume most likely part of a density flow and (3) show an aerosol air mass containing a higher proportion of small, spherical particles than the surroundings, that appears to be aerosol pollution transported from several thousand kilometres away.

  1. Polybrominated diphenyl ether (PBDE) concentrations and resulting exposure in homes in California: relationships among passive air, surface wipe and dust concentrations, and temporal variability.

    PubMed

    Bennett, D H; Moran, R E; Wu, X May; Tulve, N S; Clifton, M S; Colón, M; Weathers, W; Sjödin, A; Jones, R; Hertz-Picciotto, I

    2015-04-01

    Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in furniture foam, electronics, and other home furnishings. A field study was conducted that enrolled 139 households from California, which has had more stringent flame retardant requirements than other countries and areas. The study collected passive air, floor and indoor window surface wipes, and dust samples (investigator collected using an HVS3 and vacuum cleaner) in each home. PentaBDE and BDE209 were detected in the majority of the dust samples and many floor wipe samples, but the detection in air and window wipe samples was relatively low. Concentrations of each PBDE congener in different indoor environmental media were moderately correlated, with correlation coefficients ranging between 0.42 and 0.68. Correlation coefficients with blood levels were up to 0.65 and varied between environmental media and age group. Both investigator-collected dust and floor wipes were correlated with serum levels for a wide range of congeners. These two sample types also had a relatively high fraction of samples with adequate mass for reliable quantification. In 42 homes, PBDE levels measured in the same environmental media in the same home 1 year apart were statistically correlated (correlation coefficients: 0.57-0.90), with the exception of BDE209 which was not well correlated longitudinally. PMID:24832910

  2. Particle size distributions of Trade-Wind African dust measured in the air and after dispersal in water

    NASA Astrophysics Data System (ADS)

    Prospero, J. M.; Custals, L.

    2012-12-01

    The paleoclimate community uses dust particle size measurements in ice cores and sediments in an effort to retrieve information about dust sources and transport and the changes that occur with time. These measurements are typically made on particles suspended in water using a Coulter-type (electric zone sensing) instrument or with electro-optical measurements calibrated against a Coulter. In contrast the atmospheric community measures particles suspended in the atmosphere using instruments based on completely different principles. Because dust particles are typically complex agglomerates that can disperse in liquids, the measurements made with Coulter-type instruments cannot be easily related to atmospheric measurements. Consequently many of the assumptions made in the paleoclimate community about dust sources and transport based on particle sizes in cores cannot be readily tested against present-day measurements. We addressed this issue by making measurements of airborne dust in Barbados and Miami using a Coulter Multisizer™ 3. We collected airborne particles in two ways: 1) bulk (total) aerosol samples collected on a membrane filters, and 2) size-separated samples collected with a MOUDI cascade impactor which yields information about the degree of agglomeration of particles in different aerosol size classes. During the summer dust season, the bulk filters yield well-defined dust volume distribution peaks that are relatively stable from event-to-event at both Miami and Barbados. Volume geometric mean diameters (GMD) are centered around 2 μm; the GMD is marginally higher during heavy dust days than low-dust days. The most dramatic changes in size distributions occur during winter-spring dust events when the GMD ranges from around 1 μm to around 3 to 4 μm. It is notable that the size distributions truncate above 4 - 5 μm diameter; there are very few particles above 5 - 6 μm diameter except for single particles which could be due to contamination. We attribute

  3. Dust devils in thin air: Vortex observations at a high-elevation Mars analog site in the Argentinian Puna

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Radebaugh, Jani

    2016-04-01

    We report in situ measurements and field observations of dust devils at ~3800-4200 m elevation in the Argentine desert plateau (Puna). These first quantitative data at elevations where the ambient atmospheric pressure is only ~600-700 mbar support the notion that large and strong dust devils may be systematically more common in low-pressure conditions, although regional meteorology and/or surface thermophysical properties may also contribute.

  4. Investigation of techniques to improve continuous air monitors under conditions of high dust loading in environmental setting. 1998 annual progress report

    SciTech Connect

    Schery, S.D.; Wasiolek, P.T.; Rodgers, J.

    1998-06-01

    'Improvement in understanding of the deposition of ambient dust particles on ECAM (Environmental Continuous Air Monitor) filters, reduction of the alpha-particle interference of radon progeny and other radioactive aerosols in different particle size ranges on filters, and development of ECAM''s with increased sensitivity under dusty outdoor conditions. As of May 1, 1998 (1/2 year into the project) the research-prototype 30-cm pulsed ionization chamber (PIC) is assembled and operational with an alpha particle energy resolution of better than 45 keV for 5-MeV alpha particles. Measurements of spectral resolution for alpha particles from radon decay products have been made as a function of filter type and dust loading conditions. So far, a study of ten filter types has found that the best combination of resolution and throughput is obtained with 3.0 \\265m Millipore fluoropore and 1.0 \\265m Corning FNMB filters. Experiments with gypsum and Portland cement dust in the size range 1 to 20 \\265m indicate significant degradation in alpha particle resolution for dust loading above about 0.5 mg cm{sup -2}. Study of metalized films for possible use as a PIC window indicate a minimum broadening of 5-MeV alpha particle peaks from 43 (no film) to 301 keV (with film) for AVR film type B8 (0.20 mg cm{sup -2} polycarbonate). A modified ECAM sampling head, equipped with an optical microscopy system feeding data to a high resolution video data capture and logging instrument, was constructed. This system will enable time-lapse study of dust build-up on ECAM filters and formation of dendrite structures that can reduce alpha-particle resolution.'

  5. Health risk assessment of exposure to polybrominated diphenyl ethers (PBDEs) contained in residential air particulate and dust in Guangzhou and Hong Kong

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Zheng, Jinshu; Chan, Chuen-Yu; Huang, Min-juan; Cheung, Kwai Chung; Wong, Ming Hung

    2014-06-01

    Polybrominated diphenyl ethers (PBDEs) were measured in air particulate PM2.5 (less than 2.5 μm), TSP (Total Suspend Particle) and dust samples from different households of two major urban centers of Pearl River Delta (PRD). ∑PBDEs in PM2.5 of households in Guangzhou (GZ) (52.9-2.03 × 103 pg m-3 mean 239 pg m-3) were significantly higher than Hong Kong (HK) (0.25-160 pg m-3, mean 43.8 pg m-3). Higher ∑PBDEs occurred in indoor TSP, ranging between 117 and 1.14 × 103 pg m-3, with a median of 333 pg m-3. BDE-209 was the largest contributor to PBDEs contained in household dust, PM2.5 and TSP samples of GZ. Among the particles in household environment, PM2.5 accumulated the highest PBDEs, especially BDE-209. The constant Cparticle/Cdust values suggested that sorption is the dominant mechanism through which PBDEs are associated with settled dust and airborne particles. PBDEs were fairly uniform from urban sites to suburban sites, indicating the predominant indoor sources of PBDEs. Compared with indoor PM2.5, indoor dust ingestion made an important contribution of particle associated PBDEs exposure for adults (25 years old) and toddlers (1-2 years old). Non-dietary exposure dominated total PBDEs exposure, accounting for 91.8-99.0% exposure dose for toddlers and 45.1-82.2% for adults. Dust ingestion (69.3-96.1%) was the predominant PBDEs exposure route for toddlers.

  6. Heart Rate and Heart Rate Variability Assessment Identifies Individual Differences in Fear Response Magnitudes to Earthquake, Free Fall, and Air Puff in Mice

    PubMed Central

    Kuang, Hui; Tsien, Joe Z.; Zhao, Fang

    2014-01-01

    Fear behaviors and fear memories in rodents have been traditionally assessed by the amount of freezing upon the presentation of conditioned cues or unconditioned stimuli. However, many experiences, such as encountering earthquakes or accidental fall from tree branches, may produce long-lasting fear memories but are behaviorally difficult to measure using freezing parameters. Here, we have examined changes in heartbeat interval dynamics as physiological readout for assessing fearful reactions as mice were subjected to sudden air puff, free-fall drop inside a small elevator, and a laboratory-version earthquake. We showed that these fearful events rapidly increased heart rate (HR) with simultaneous reduction of heart rate variability (HRV). Cardiac changes can be further analyzed in details by measuring three distinct phases: namely, the rapid rising phase in HR, the maximum plateau phase during which HRV is greatly decreased, and the recovery phase during which HR gradually recovers to baseline values. We showed that durations of the maximum plateau phase and HR recovery speed were quite sensitive to habituation over repeated trials. Moreover, we have developed the fear resistance index based on specific cardiac response features. We demonstrated that the fear resistance index remained largely consistent across distinct fearful events in a given animal, thereby enabling us to compare and rank individual mouse’s fear responsiveness among the group. Therefore, the fear resistance index described here can represent a useful parameter for measuring personality traits or individual differences in stress-susceptibility in both wild-type mice and post-traumatic stress disorder (PTSD) models. PMID:24667366

  7. Emission of di-2-ethylhexyl phthalate from PVC flooring into air and uptake in dust: emission and sorption experiments in FLEC and CLIMPAQ.

    PubMed

    Clausen, Per Axel; Hansen, Vivi; Gunnarsen, Lars; Afshari, Alireza; Wolkoff, Peder

    2004-05-01

    The emission of di-2-ethylhexyl phthalate (DEHP) from a PVC flooring was studied for up to 472 days in both the FLEC (Field and Laboratory Emission Cell) and the CLIMPAQ (Chamberfor Laboratory Investigations of Materials, Pollution, and Air Quality). The loading of the CLIMPAQs was varied but was constant in the FLECs. The sorption properties of FLEC and CLIMPAQ were investigated using different methods. In addition, the uptake of DEHP by office floor dust on the PVC flooring was studied in CLIMPAQ experiments. The concentration versus time curves in both FLECs and CLIMPAQs increased slowly over about 150 days and reached a quasi-static equilibrium at 1 microg m(-3). The main conclusions were that (i) the emission rate of DEHP was limited by gas-phase mass transport and (ii) the dust layer increased the emission rate by increasing the external concentration gradient above the surface of the PVC. These conclusions were based on the facts that the specific emission rate was inversely proportional to the loading and that the dust had sorbed about four times as much DEHP over a 68-day period as emitted in the gas-phase experiments. About one-half of the emitted DEHP was deposited on the internal surfaces of both the FLEC and the CLIMPAQ. PMID:15180047

  8. Dust Storms: Why Are Dust Storms a Concern?

    MedlinePlus

    ... US Border Regions US Southwest Locations Abandoned Mines Agricultural Runoff Airplanes and Air Travel Algae Blooms Animal ... Links from MedlinePlus (National Library of Medicine) Air Pollution Asthma Valley Fever More Links Dust Control On ...

  9. Geomorphic and Chemical Characteristics of Dust and Soil in the Eastern Great Basin of Utah, U.S.A.

    NASA Astrophysics Data System (ADS)

    Hahnenberger, M.; Nicoll, K.; Perry, K. D.

    2014-12-01

    This study identifies anthropogenically disturbed areas and barren playa surfaces as the two primary dust source types that repeatedly contribute to dust storm events in the eastern Great Basin of western Utah, U.S.A. Further, dust samples were found to be distinctally different elementally compared to soil samples in this region. This analysis used MODIS and USDA Land cover data to identify 4 major and 5 secondary source areas for dust in this region, which produce dust primarily during the spring and fall months and during moderate or greater drought conditions. The largest number of observed dust plumes (~ 60% of all plumes) originated from playas (ephemeral lakes) and are classified as barren land cover with a silty clay soil sediment surface. Anthropogenic disturbance is necessary to produce dust from the vegetated landscape in the eastern Great Basin, as evidenced by the new dust source active from 2008 to 2010 in the area burned by the 2007 Milford Flat Fire; this fire was the largest in Utah's history due to extensive cover of invasive cheatgrass along with drought conditions. Dust and soil samples contain similar enrichments of major soil elements, however, dust samples were significantly more enriched in Na derived from the surface salts of the Sevier Dry Lake. Trace elements were generally more enriched in dust samples and had larger enrichment values than seen in previous studies. Further, for dust and soil samples, the fine fraction (<2.5 μm) was more enriched in trace elements than the coarse fraction (2.5 to 10 μm). Composition of dust transported has influences on human health, ecosystem functioning, and biogeochemical cycling. Dust storms in the eastern Great Basin negatively impact air quality and transportation in the populated regions of Utah; this study details an improved forecasting protocol for dust storm events that will benefit transportation planning and improve public health.

  10. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  11. PARTICULATE CONTROL FOR FUGITIVE DUST

    EPA Science Inventory

    The report gives results of a study of particulate control for fugitive dust. Study results indicate that many Air Quality Control Regions (AQCRs) do not meet ambient air standards for particulates. In a majority of these ACQRs, the emissions from fugitive dust sources are higher...

  12. Saharan dust outbreaks and iberulite episodes

    NASA Astrophysics Data System (ADS)

    Diaz-Hernandez, Jose L.; Sanchez-Navas, Antonio

    2016-06-01

    Mineral dust aerosols coming from the arid and semiarid regions of the world can aggregate and form microspherulites under special atmospheric conditions. This is the case for iberulites, formed in the atmosphere from Saharan dust intrusions into the southern Iberian Peninsula during the summer, prompting a noteworthy case of dust accretion unique in the world. This study consists of a long-term monitoring of Saharan dust outbreaks producing haze that reaches the southern Iberian Peninsula. Aerosol concentration, relative humidity, and temperature time series available at the ground stations in this area indicate sharp variations of these atmospheric variables during the iberulite-forming events. Most of these events occurred during the summer (60%), with 65 episodes for the period 2005-2013, in which 107 plumes reached the Iberian Peninsula. Iberulite episodes lasted 5 days on average, during which an initial increase of particulate matter (PM) levels and temperature, accompanied by a decrease in relative humidity, was registered until the third day. These trends reversed when the plume began to abate. Our data also indicate that iberulites form during dusty episodes when a minimum threshold in the content of large aerosol particles (PM10) reached concentrations above 15 µg × m-3. Surface evaporation due to the sharply rising air temperatures give rise to clouds associated with the plume, where the water droplets that formed from condensation capture large amounts of aerosols as they fall. In this sense, muddy raindrop impacts with variable water:dust ratios recorded during red-rain episodes are interpreted as the precursor of the iberulites. A singular process of dust aggregation is here proposed for the formation of iberulites.

  13. Students fall for Fall Meeting

    NASA Astrophysics Data System (ADS)

    Smedley, Kara

    2012-02-01

    From Boston to Beijing, thousands of students traveled to San Francisco for the 2011 AGU Fall Meeting. Of those who participated, 183 students were able to attend thanks to AGU's student travel grant program, which assists students with travel costs and seeks to enrich the meeting through ethnic and gender diversity. Students at Fall Meeting enjoyed a variety of programs and activities designed to help them better network with their peers, learn about new fields, and disseminate their research to the interested public. More than 800 students attended AGU's first annual student mixer, sharing drinks and ideas with fellow student members and future colleagues as well as forging new friendships and intellectual relationships.

  14. Hazards of explosives dusts: Particle size effects

    SciTech Connect

    Cashdollar, K L; Hertzberg, M; Green, G M

    1992-02-01

    At the request of the Department of Energy, the Bureau of Mines has investigated the hazards of military explosives dispersed as dust clouds in a 20-L test chamber. In this report, the effect of particle size for HMX, HNS, RDX, TATB, and TNT explosives dusts is studied in detail. The explosibility data for these dusts are also compared to those for pure fuel dusts. The data show that all of the sizes of the explosives dusts that were studied were capable of sustaining explosions as dust clouds dispersed in air. The finest sizes (<10 [mu]m) of explosives dusts were less reactive than the intermediate sizes (20 to 60 [mu]m); this is opposite to the particle size effect observed previously for the pure fuel dusts. At the largest sizes studied, the explosives dusts become somewhat less reactive as dispersed dust clouds. The six sizes of the HMX dust were also studied as dust clouds dispersed in nitrogen.

  15. In-depth survey report: control technology for falling solids at Cincinnati Paint and Varnish, Cincinnati, Ohio

    SciTech Connect

    Heitbrink, W.A.

    1988-04-01

    A visit was made to the Cincinnati Paint and Varnish Company, Cincinnati, Ohio, to determine the effectiveness of control measures used to contain dust generated during the manufacturing of custom coatings. Dust arose when 50 pound bags of different powdered materials, titanium dioxide, talc, and crystalline silica, were emptied into 600-gallon mixing tanks by a worker. The worker slit the bags with a knife, lifted the bag, poured the contents into the mixer, and returned the empty bags to the floor. Exterior surfaces of the bags were dusty; handling them released some dust into the atmosphere. A slot hood was used to capture dust generated during the operation. Air velocity toward th slot hood along the lip of the tank where the bags were emptied ranged from 50 to 100 feet per minute. The total dust concentrations determined for crystalline silica during this operation averaged 3.0mg/cum. During a revisit to the site this worker's exposure was below 0.15mg/cum for a time-weighted average of less than 0.004 mg/m/sup 3/. The difference in liquid level in the tank at the time each powdered ingredient was added may have significantly affected the amount of dust released. Measurements of the actual process indicated that the silica had to fall almost 1 meter before reaching any liquid in the mixing tank whereas the talc had to fall only 25 centimeters.

  16. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR EXTRACTION OF METALS FROM SOIL, DUST, AIR FILTER, AND SURFACE AND DERMAL SAMPLES FOR AA (GRAPHITE FURNACE OR FLAME) OR ICP-AES ANALYSIS (BCO-L-3.1)

    EPA Science Inventory

    The purpose of this SOP is to describe the acid digestion of soil, house dust, air filter, and surface or dermal wipe samples for analysis using inductively coupled plasma atomic emissions spectrometry (ICP-AES) and/or graphite furnace atomic absorption spectrometry (GFAAS) or fl...

  17. Applications Using AIRS Data

    NASA Astrophysics Data System (ADS)

    Ray, S. E.; Pagano, T. S.; Fetzer, E. J.; Lambrigtsen, B.; Olsen, E. T.; Teixeira, J.; Licata, S. J.; Hall, J. R.; Thompson, C. K.

    2015-12-01

    The Atmospheric Infrared Sounder (AIRS) on NASA's Aqua spacecraft has been returning daily global observations of Earth's atmospheric constituents and properties since 2002. With a 12-year data record and daily, global observations in near real-time, AIRS data can play a role in applications that fall under many of the NASA Applied Sciences focus areas. For vector-borne disease, research is underway using AIRS near surface retrievals to assess outbreak risk, mosquito incubation periods and epidemic potential for dengue fever, malaria, and West Nile virus. For drought applications, AIRS temperature and humidity data are being used in the development of new drought indicators and improvement in the understanding of drought development. For volcanic hazards, new algorithms using AIRS data are in development to improve the reporting of sulfur dioxide concentration, the burden and height of volcanic ash and dust, all of which pose a safety threat to aircraft. In addition, anomaly maps of many of AIRS standard products are being produced to help highlight "hot spots" and illustrate trends. To distribute it's applications imagery, AIRS is leveraging existing NASA data frameworks and organizations to facilitate archiving, distribution and participation in the BEDI. This poster will communicate the status of the applications effort for the AIRS Project and provide examples of new maps designed to best communicate the AIRS data.

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

  19. The case for a southeastern Australian Dust Bowl, 1895-1945

    NASA Astrophysics Data System (ADS)

    Cattle, Stephen R.

    2016-06-01

    Australia has an anecdotal history of severe wind erosion and dust storm activity, but there has been no lasting public perception of periods of extreme dust storm activity in this country, such as that developed in the USA following the Dust Bowl of the 1930s. Newspaper accounts of droughts and dust storms in southeastern (SE) Australia between 1895 and 1945 suggest that, at various times, the scale of these events was comparable to those experienced in the USA Dust Bowl. During this 50-year period, average annual rainfall values in this region were substantially below long-term averages, air temperatures were distinctly warmer, marginal lands were actively cropped and grazed, and rabbits were a burgeoning grazing pest. From the beginning of the Federation Drought of 1895-1902, dust storm activity increased markedly, with the downwind coastal cities of Sydney and Melbourne experiencing dust hazes, dust storms and falls of red rain relatively regularly. Between 1935 and 1945, Sydney and Melbourne received ten and nine long-distance dust events, respectively, with the years of 1938 and 1944/45 being the most intensely dusty. Entire topsoil horizons were blown away, sand drift was extreme, and crops and sheep flocks were destroyed. Although these periods of extreme dust storm activity were not as sustained as those experienced in the USA in the mid-1930s, there is a strong case to support the contention that SE Australia experienced its own extended, somewhat episodic version of a Dust Bowl, with a similar combination of causal factors and landscape effects.

  20. Dust Detector

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.

    2001-01-01

    We discuss a recent sounding rocket experiment which found charged dust in the Earth's tropical mesosphere. The dust detector was designed to measure small (5000 - 10000 amu.) charged dust particles, most likely of meteoric origin. A 5 km thick layer of positively charged dust was found at an altitude of 90 km, in the vicinity of an observed sporadic sodium layer and sporadic E layer. The observed dust was positively charged in the bulk of the dust layer, but was negatively charged near the bottom.

  1. [Comparison between calculation- and measurement-based assessments of the effects of ambient air dust concentration on the environment and health status of the population living in the vicinity of a mineral mining plant].

    PubMed

    Wiecek, Edward; Woźniak, Helena

    2004-01-01

    Airborne and PM10 fraction dust concentrations were measured at seven measurement points in the area occupied by the plant. A GRIMM 1.105 laser meter was used to determine automatically total dust and PM10 fraction concentrations at 1 min intervals. The measurements were continued for 1 to 3 days at selected measurement points. The results were used to calculate the 30-min and mean 24-h (C24) concentrations. Significant differences were found to exist in the assessment based on the calculated and measured results of the ambient air dust concentrations. The calculation-based assessment did not predict any values above admissible limits, while the measurement-based assessment resulted in dust concentration values dangerous to the exposed population living in the vicinity of the plant, over both short (days) and long (years) time intervals. In emergency situation, when the dust-collection system was inoperative, dust concentrations in the ambient atmosphere of the plant were even 100 times higher than the current admissible values. PMID:15156772

  2. Influence of quarry mining dust on PM2.5 in a city adjacent to a limestone quarry: Seasonal characteristics and source contributions.

    PubMed

    Peng, Xing; Shi, Guo-Liang; Zheng, Jun; Liu, Jia-Yuan; Shi, Xu-Rong; Xu, Jiao; Feng, Yin-Chang

    2016-04-15

    To understand the influence of quarry mining dust on particulate matter, ambient PM2.5 and quarry mining dust source samples were collected in a city near quarry facilities during 2013-2014. Samples were subject to chemical analysis for dust-related species (Al, Si, Ca, Fe, Ti), tracer metals, carbon components and water-soluble ions. Seasonal variations of PM2.5 and its main chemical components were investigated. Distinctive seasonal variations of PM2.5 were observed, with the highest PM2.5 concentrations (112.42μgm(-3)) in fall and lowest concentrations in summer (45.64μgm(-3)). For dust-related species, mass fractions of Si and Al did not show obvious seasonal variations, whereas Ca presented higher fractions in spring and summer and lower fractions in fall and winter. A combined receptor model (PMF-CMB) was applied to quantify the quarry mining dust contribution to PM2.5. Seven sources were identified, including quarry mining dust, soil dust, cement dust, coal combustion vehicles, secondary sulfate and secondary nitrate. On a yearly average basis, the contribution of quarry mining dust to PM2.5 was 6%. The contribution of soil dust to PM2.5 was comparable with cement dust (13% and 13%, respectively). Other identified sources included vehicle, secondary sulfate, secondary nitrate and coal combustion, which contributed 23, 15, 9 and 18% of the total mass, respectively. Air mass residence time (AMRT) analysis showed that northeast and southeast regions might be the major PM2.5 source during the sampling campaign. The findings of this study can be used to understand the characteristics of quarry mining dust and control strategies for PM2.5. PMID:26851880

  3. FINAL REPORT. INVESTIGATIONS OF TECHNIQUES TO IMPROVE CONTINUOUS AIR MONITORS UNDER CONDITIONS OF HIGH DUST LOADING IN ENVIRONMENTAL SETTINGS

    EPA Science Inventory

    The overall objective was to carry out studies to improve the detection of plutonium aerosols by environmental continuous air monitors (ECAMs), particularly in dusty environments. A number of alpha-particle ECAMs are used at DOE sites such as Los Alamos National Laboratory (LANL)...

  4. INVESTIGATION OF TECHNIQUES TO IMPROVE CONTINUOUS AIR MONITORS UNDER CONDITIONS OF HIGH DUST LOADING IN ENVIRONMENTAL SETTINGS

    EPA Science Inventory

    The investigation is an in-depth exploration of environmental influences that can cause degradation of the performance (sensitivity, alarm functionality, etc.) of Continuous Air Monitors (CAMs), such as the LANL/Canberra alpha-particle CAM, and a study of techniques to correct fo...

  5. Dust, Climate, and Human Health

    NASA Astrophysics Data System (ADS)

    Maynard, N. G.

    2003-12-01

    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

  6. 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.

  7. 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.

  8. Cosmic dust

    NASA Technical Reports Server (NTRS)

    Brownlee, Donald E.; Sandford, Scott A.

    1992-01-01

    Dust is a ubiquitous component of our galaxy and the solar system. The collection and analysis of extraterrestrial dust particles is important to exobiology because it provides information about the sources of biogenically significant elements and compounds that accumulated in distant regions of the solar nebula and that were later accreted on the planets. The topics discussed include the following: general properties of interplanetary dust; the carbonaceous component of interplanetary dust particles; and the presence of an interstellar component.

  9. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    article title:  Massive Dust Storm over Australia     View ... at JPL September 22, 2009 - Massive dust storm over Australia. project:  MISR category:  ... Sep 22, 2009 Images:  Dust Storm location:  Australia and New Zealand ...

  10. Sahara Dust

    Atmospheric Science Data Center

    2013-04-15

    article title:  Casting Light and Shadows on a Saharan Dust Storm     ... (nadir) camera. High-altitude cirrus clouds cast shadows on the underlying ocean and dust layer, which are visible in shades of ... was unable to retrieve elevation data. However, the edges of shadows cast by the cirrus clouds onto the dust (indicated by blue and cyan ...

  11. Circumstellar dust

    NASA Technical Reports Server (NTRS)

    Dwek, E.

    1986-01-01

    The presence of dust in the general interstellar medium is inferred from the extinction, polarization, and scattering of starlight; the presence of dark nebulae; interstellar depletions; the observed infrared emission around certain stars and various types of interstellar clouds. Interstellar grains are subject to various destruction mechanisms that reduce their size or even completely destroy them. A continuous source of newly formed dust must therefore be present for dust to exist in the various phases of the interstellar medium (ISM). The working group has the following goals: (1) review the evidences for the formation of dust in the various sources; (2) examine the clues to the nature and composition of the dust; (3) review the status of grain formation theories; (4) examine any evidence for the processing of the dust prior to its injection into the interstellar medium; and (5) estimate the relative contribution of the various sources to the interstellar dust population.

  12. Geomorphic and land cover identification of dust sources in the eastern Great Basin of Utah, U.S.A.

    NASA Astrophysics Data System (ADS)

    Hahnenberger, Maura; Nicoll, Kathleen

    2014-01-01

    This study identifies anthropogenically disturbed areas and barren playa surfaces as the two primary dust source types that repeatedly contribute to dust storm events in the eastern Great Basin of western Utah, U.S.A. This semi-arid desert region is an important contributor to dust production in North America, with this study being the first to specifically identify and characterize regional dust sources. From 2004 to 2010, a total of 51 dust event days (DEDs) affected the air quality in Salt Lake City, UT. MODIS satellite imagery during 16 of these DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas. A total of 168 plumes were identified, and showed mobilization of dust from Quaternary deposits located within the Bonneville Basin. This analysis identifies 4 major and 5 secondary source areas for dust in this region, which produce dust primarily during the spring and fall months and during moderate or greater drought conditions, with a Palmer Drought Index (PDI) of - 2 or less. The largest number of observed dust plumes (~ 60% of all plumes) originated from playas (ephemeral lakes) and are classified as barren land cover with a silty clay soil sediment surface. Playa surfaces in this region undergo numerous recurrent anthropogenic disturbances, including military operations and anthropogenic water withdrawal. Anthropogenic disturbance is necessary to produce dust from the vegetated landscape in the eastern Great Basin, as evidenced by the new dust source active from 2008 to 2010 in the area burned by the 2007 Milford Flat Fire; this fire was the largest in Utah's history due to extensive cover of invasive cheatgrass (Bromus tectorum) along with drought conditions. However, dust mobilization from the Milford Flat Burned Area was limited to regions that had been significantly disturbed by post-fire land management techniques that consisted of seeding, followed by chaining or tilling of the soil. Dust storms in the eastern

  13. A Piece of Paper Falling Faster than Free Fall

    ERIC Educational Resources Information Center

    Vera, F.; Rivera, R.

    2011-01-01

    We report a simple experiment that clearly demonstrates a common error in the explanation of the classic experiment where a small piece of paper is put over a book and the system is let fall. This classic demonstration is used in introductory physics courses to show that after eliminating the friction force with the air, the piece of paper falls…

  14. Middle East Health and Air Quality Utilizing NASA EOS in the Saharan and Arabian Deserts to Examine Dust Particle Size and Mineralogy of Aerosols

    NASA Technical Reports Server (NTRS)

    Keeton, Tiffany; Barrick, Bradley; Cooksey, Kirstin; Cowart, Kevin; Florence, Victoria; Herdy, Claire; Padgett-Vasquez, Steve; Luvall, Jeffrey; Molthan, Andrew

    2012-01-01

    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 2.5micron (PM2.5) can cause long-term damage to the human respiratory system. NASA fs Earth Observing System (EOS) can be used to determine spectral characteristics of dust particles and 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 Angstrom Exponent. Brightness Temperature Difference (BTD) equation was used to determine the area of the dust storm. The Moderate-resolution Imaging Spectroradiometer (MODIS) on Terra satellite was utilized in calculating BTD. Mineral composition of a dust storm that occurred 17 April 2008 near Baghdad was determined using imaging spectrometer data from the JPL 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 Bodele Depression in the Sahara Desert on 7 June 2003.

  15. Installation restoration program. Site investigation report for IRP site No. 12 and 13, South Dakota Air National Guard, 114th Fighter Wing, Joe Foss Field, Sioux Falls, South Dakota - Volume 1. Final report

    SciTech Connect

    1996-02-01

    Site Investigation Report for IRP Site No 12 and 13, South Dakota Air National Guard, 114th Fighter Wing, Joe Foss Field, Sioux Falls, South Dakota, Volume I. This is the first volume of a two volume site investigation report. Two sites (Site 12 - Ramp area and Site 13 - Motor Vehicle Maintenance Facility) was investigated under the Installation Restoration Program. Soil and groundwater samples were collected and analyzed. No further action was recommended on site 13 and quarterly sampling was recommended for site 12. South Dakota Regulators have agreed to both recommendations. Decision documents will be prepared for each site.

  16. Large Aperture Electrostatic Dust Detector

    SciTech Connect

    C.H. Skinner, R. Hensley, and A.L Roquemore

    2007-10-09

    Diagnosis and management of dust inventories generated in next-step magnetic fusion devices is necessary for their safe operation. A novel electrostatic dust detector, based on a fine grid of interlocking circuit traces biased to 30 or 50 ν has been developed for the detection of dust particles on remote surfaces in air and vacuum environments. Impinging dust particles create a temporary short circuit and the resulting current pulse is recorded by counting electronics. Up to 90% of the particles are ejected from the grid or vaporized suggesting the device may be useful for controlling dust inventories. We report measurements of the sensitivity of a large area (5x5 cm) detector to microgram quantities of dust particles and review its applications to contemporary tokamaks and ITER.

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

    PubMed Central

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

    1981-01-01

    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. PMID:7317296

  18. NOVA Fall 2000 Teacher's Guide.

    ERIC Educational Resources Information Center

    Ransick, Kristina; Rosene, Dale; Sammons, Fran Lyons; Sammons, James

    This teacher's guide complements six programs that aired on the Public Broadcasting System (PBS) in the fall of 2000. Programs include: (1) "Lincoln's Secret Weapon"; (2) "Hitler's Lost Sub"; (3) "Runaway Universe"; (4) "Garden of Eden"; (5) "Dying to Be Thin"; and (6) "Japan's Secret Garden". It provides activity set-ups related to the programs…

  19. Improved optical probe for monitoring dust explosions

    NASA Astrophysics Data System (ADS)

    Conti, R. S.; Cashdollar, K. L.; Liebman, I.

    1982-03-01

    An improved optical probe was developed to monitor dust-cloud concentration in explosions even in the presence of dust flame radiation. Principal features of the probe include a pulsed light-emitting diode and a photodetector with optical interference filter to reduce flame radiation. The probe has a U-shaped configuration and air jets to keep the windows dust free. Experimental data are presented for a coal dust explosion.

  20. Selecting baghouse dust collectors

    SciTech Connect

    Moore, S.; Rubak, J.; Jolin, M. |

    1996-10-01

    Control of nuisance or process dusts generated within a plant is a vital concern with today`s growing emphasis on indoor air quality. In the past, many companies simply moved these contaminants away from workers and discharged them into the atmosphere. More stringent pollution control requirements now make this course of action unacceptable. Also, in some cases there is a need to recover high-value dusts, such as chemicals or precious metals. As a result, proper design and selection of a dust collection system are more critical than ever. There are two types of fabric filter dust collection systems commonly used today: baghouses and cartridges. Baghouses were the first collection systems with fabric media (in the form of long tubes, or bags) for removal of contaminants. The versatility of the baghouse--coupled with constant technological refinements--have made it a long-standing favorite among specifiers of pollution control equipment. In fact, baghouses account for more than 80% of all fabric filter dust collection systems in use today. Cartridge dust collectors use rigidly pleated filter elements instead of bags, making it possible to accommodate a large amount of filter surface area in a comparatively small package. Cartridge collectors also offer high efficiency and low pressure drop.

  1. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, Dániel; Lauretta, Dante S.

    2010-01-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  2. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, D.´niel; Lauretta, Dante S.

    2014-02-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  3. 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

  4. Falls and Older Adults

    MedlinePlus

    ... rises with age. Click for more information Falls Lead to Fractures, Trauma Each year, more than 1. ... and injury deaths. Fractures caused by falls can lead to hospital stays and disability. Most often, fall- ...

  5. Home Improvements Prevent Falls

    MedlinePlus

    ... on. Feature: Falls and Older Adults Home Improvements Prevent Falls Past Issues / Winter 2014 Table of Contents ... or home modification programs to help older people prevent falls. Check with your local health department, senior ...

  6. Falls in Nursing Homes

    MedlinePlus

    ... for health care providers. Learn More Falls in Nursing Homes Recommend on Facebook Tweet Share Compartir On ... 5 Why do falls occur more often in nursing homes? Falling can be a sign of other ...

  7. Aeolian transport of biota with dust: A wind tunnel experiment

    NASA Astrophysics Data System (ADS)

    Rivas, J. A., Jr.; Gill, T. E.; Van Pelt, R. S.; Walsh, E.

    2015-12-01

    Ephemeral wetlands are ideal sources for dust emission, as well as repositories for dormant stages of aquatic invertebrates. An important component of invertebrate dispersal and colonization to new areas is the ability to be entrained into the atmosphere. Aquatic invertebrate eggs fall within the size of dust and sand grains (30-600μm), are less dense and aerodynamically shaped. We have shown previously that aquatic invertebrates can be dispersed long distances in dust storms but the extent of transport of taxa based on diapausing egg size/morphology has not been investigated. Here, we control the wind erosion process in a wind tunnel to test entrainment of diapausing stages of brine shrimp, clam shrimp, tadpole shrimp, fairy shrimp, Daphnia, and the rotifers Brachionus plicatilis and B. calyciflorus into the air by saltation. Diapausing eggs were mixed with sterilized wind-erodible soil. The soil/egg mixture was moistened with distilled water and air dried to form a crust. Dust was generated in a wind tunnel by releasing sand grains that act as saltator material similar to wind-entrained natural sands. Maximum wind velocity was 10m/s and entrained particles were sampled through an isokinetic horizontal intake opening. Aeolian sediment was collected from three points in the system; transfer section for coarse sediment, the pan subtending a settling chamber for finer saltation-sized sediment, and two paper filters for suspension-sized sediment. Samples were then passed through 250 and 350 μm sieves to remove abrader sand and rehydrated with various sterile media depending on the type of organism. We retrieved viable brine, fairy, and tadpole shrimp, ostracods, Daphnia, and diapausing eggs of the rotifers after hydration. This experiment demonstrates that resting stages of many invertebrates can be wind-eroded due to size and egg morphology and remain viable under controlled conditions mimicking dust emission.

  8. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having...

  9. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having...

  10. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    ... contrast strongly with the dust storm that swept across Iraq and Saudi Arabia on May 13, 2004 (bottom panels). These data products from ... as yellowish ripples that obscure a large part of southern Iraq. The dust is easy to discern over the dark waters of the teardrop-shaped ...

  11. Dust Devils Seen by Spirit

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 Annotated

    At the Gusev site recently, skies have been very dusty, and on its 421st sol (March 10, 2005) NASA's Mars Exploration Rover Spirit spied two dust devils in action. This pair of images is from the rover's rear hazard-avoidance camera. Views of the Gusev landing region from orbit show many dark streaks across the landscape -- tracks where dust devils have removed surface dust to show relatively darker soil below -- but this is the first time Spirit has photographed an active dust devil.

    Scientists are considering several causes of these small phenomena. Dust devils often occur when the Sun heats the surface of Mars. Warmed soil and rocks heat the layer of atmosphere closest to the surface, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado. Another possibility is that a flow structure might develop over craters as wind speeds increase. As winds pick up, turbulence eddies and rotating columns of air form. As these columns grow in diameter they become taller and gain rotational speed. Eventually they become self-sustaining and the wind blows them down range.

    One sol before this image was taken, power output from Spirit's solar panels went up by about 50 percent when the amount of dust on the panels decreased. Was this a coincidence, or did a helpful dust devil pass over Spirit and lift off some of the dust?

    By comparing the separate images from the rover's different cameras, team members estimate that the dust devils moved about 500 meters (1,640 feet) in the 155 seconds between the navigation camera and hazard-avoidance camera frames; that equates to about 3 meters per second (7 miles per hour). The dust devils appear to be about 1,100 meters (almost three-quarters of a mile) from the rover.

  12. Andromeda's dust

    SciTech Connect

    Draine, B. T.; Aniano, G.; Krause, Oliver; Groves, Brent; Sandstrom, Karin; Klaas, Ulrich; Linz, Hendrik; Rix, Hans-Walter; Schinnerer, Eva; Schmiedeke, Anika; Walter, Fabian; Braun, Robert; Leroy, Adam E-mail: ganiano@ias.u-psud.fr

    2014-01-10

    Spitzer Space Telescope and Herschel Space Observatory imaging of M31 is used, with a physical dust model, to construct maps of dust surface density, dust-to-gas ratio, starlight heating intensity, and polycyclic aromatic hydrocarbon (PAH) abundance, out to R ≈ 25 kpc. The global dust mass is M {sub d} = 5.4 × 10{sup 7} M {sub ☉}, the global dust/H mass ratio is M {sub d}/M {sub H} = 0.0081, and the global PAH abundance is (q {sub PAH}) = 0.039. The dust surface density has an inner ring at R = 5.6 kpc, a maximum at R = 11.2 kpc, and an outer ring at R ≈ 15.1 kpc. The dust/gas ratio varies from M {sub d}/M {sub H} ≈ 0.026 at the center to ∼0.0027 at R ≈ 25 kpc. From the dust/gas ratio, we estimate the interstellar medium metallicity to vary by a factor ∼10, from Z/Z {sub ☉} ≈ 3 at R = 0 to ∼0.3 at R = 25 kpc. The dust heating rate parameter (U) peaks at the center, with (U) ≈ 35, declining to (U) ≈ 0.25 at R = 20 kpc. Within the central kiloparsec, the starlight heating intensity inferred from the dust modeling is close to what is estimated from the stars in the bulge. The PAH abundance reaches a peak q {sub PAH} ≈ 0.045 at R ≈ 11.2 kpc. When allowance is made for the different spectrum of the bulge stars, q {sub PAH} for the dust in the central kiloparsec is similar to the overall value of q {sub PAH} in the disk. The silicate-graphite-PAH dust model used here is generally able to reproduce the observed dust spectral energy distribution across M31, but overpredicts 500 μm emission at R ≈ 2-6 kpc, suggesting that at R = 2-6 kpc, the dust opacity varies more steeply with frequency (with β ≈ 2.3 between 200 and 600 μm) than in the model.

  13. "Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Smith, P.; White, B.; Farrell, W.

    1999-01-01

    Dust devils are familiar sites in the and regions of the world: they can produce quite spectacular displays of dust lofting when the vortices scavenge very loose dust from a dry lake bed or from recently disturbed agricultural fields. If one were to arrive at the center of an arid region, take one photograph, or even a series of photographs over a period of several days, then return the images for laboratory analysis, it would be most likely concluded that the region was inactive from an aeolian perspective. No images of general dust movement were obtained, nor were any dust devils "caught on camera" owing to their ephemeral and unpredictable appearance, and the fact that there was deceptively little residue of their actions. If, however, a camera were to take a 360 degree continuous recording over a period of a year, and the film were then to be shown at high speed over a period a several minutes, the impression might be that of a region ravaged by air vorticity and dust movement. Extrapolate this over geological time, and it is possible to visualize dust devils as prime aeolian agents, rather than insignificant vagaries of nature, On Mars, the thin atmosphere permits the surface of the planet to be heated but it does not itself retain heat with the capacity of the earth's atmosphere. This gives rise to greater thermal instability near the surface of Mars as "warm" air pockets diapiritically inject themselves into higher atmospheric layers. Resulting boundary-layer vorticity on Mars might therefore be expected to produce dust devils in abundance, if only seasonally. The spectacular images of dust devils obtained by Pathfinder within its brief functional period on the planet testify to the probability of highly frequent surface vorticity in light of the above reasoning about observational probability. Notably, the Pathfinder devils appeared to be at least a kilometer in height. There are several consequences for the geology of Mars, and for human exploration, if

  14. "Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Smith, P.; White, B.; Farrell, W.

    1999-09-01

    Dust devils are familiar sites in the and regions of the world: they can produce quite spectacular displays of dust lofting when the vortices scavenge very loose dust from a dry lake bed or from recently disturbed agricultural fields. If one were to arrive at the center of an arid region, take one photograph, or even a series of photographs over a period of several days, then return the images for laboratory analysis, it would be most likely concluded that the region was inactive from an aeolian perspective. No images of general dust movement were obtained, nor were any dust devils "caught on camera" owing to their ephemeral and unpredictable appearance, and the fact that there was deceptively little residue of their actions. If, however, a camera were to take a 360 degree continuous recording over a period of a year, and the film were then to be shown at high speed over a period a several minutes, the impression might be that of a region ravaged by air vorticity and dust movement. Extrapolate this over geological time, and it is possible to visualize dust devils as prime aeolian agents, rather than insignificant vagaries of nature, On Mars, the thin atmosphere permits the surface of the planet to be heated but it does not itself retain heat with the capacity of the earth's atmosphere. This gives rise to greater thermal instability near the surface of Mars as "warm" air pockets diapiritically inject themselves into higher atmospheric layers. Resulting boundary-layer vorticity on Mars might therefore be expected to produce dust devils in abundance, if only seasonally. The spectacular images of dust devils obtained by Pathfinder within its brief functional period on the planet testify to the probability of highly frequent surface vorticity in light of the above reasoning about observational probability. Notably, the Pathfinder devils appeared to be at least a kilometer in height. There are several consequences for the geology of Mars, and for human exploration, if

  15. Electret-based passive dust sampler: sampling of organic dusts.

    PubMed

    Brown, R C; Hemingway, M A; Wake, D; Thorpe, A

    1996-09-01

    Passive samplers are light, convenient and cheap. However, the sample size tends to be small and a correlation exercise between the results of a passive sampler and a conventional sampler must be carried out. The design principles and mode of action of an electret-based passive dust sampler are described. The device captures dust particles at a rate independent of the velocity of air except when this is very low but dependent on the electrical properties of the dust being sampled. Experimental results are presented of measurements made in bakeries, pig farms, a dairy farm, an arable farm and a rubber-manufacturing plant. Correlation between measurements made with the passive sampler and measurements of inhalable dust performed by other means are reasonable. The results are interpreted in terms of the physical properties of the dust being sampled. PMID:8831282

  16. Saharan Dust Fertilizing Atlantic Ocean and Amazon Rainforest via Long-range Transport and Deposition: A Perspective from Multiyear Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Yu, H.; Chin, M.; Yuan, T.; Bian, H.; Remer, L. A.; Prospero, J. M.; Omar, A. H.; Winker, D. M.; Yang, Y.; Zhang, Y.; Zhang, Z.; Zhao, C.

    2015-12-01

    Massive dust emitted from Sahara desert is carried by trade winds across the tropical Atlantic Ocean, reaching the Amazon Rainforest and Caribbean Sea. Airborne dust degrades air quality and interacts with radiation and clouds. Dust falling to land and ocean adds essential nutrients that could increase the productivity of terrestrial and aquatic ecosystems and modulate the biogeochemical cycles and climate. The resultant climate change will feed back on the production of dust in Sahara desert and its subsequent transport and deposition. Understanding the connections among the remote ecosystems requires an accurate quantification of dust transport and deposition flux on large spatial and temporal scales, in which satellite remote sensing can play an important role. We provide the first multiyear satellite-based estimates of altitude-resolved across-Atlantic dust transport and deposition based on eight-year (2007-2014) record of aerosol three-dimensional distributions from the CALIPSO lidar. On a basis of the 8-year average, 179 Tg (million tons) of dust leaves the coast of North Africa and is transported across Atlantic Ocean, of which 102, 20, and 28 Tg of dust is deposited into the tropical Atlantic Ocean, Caribbean Sea, and Amazon Rainforest, respectively. The dust deposition adds 4.3 Tg of iron and 0.1 Tg of phosphorus to the tropical Atlantic Ocean and Caribbean Sea where the productivity of marine ecosystem depends on the availability of these nutrients. The 28 Tg of dust provides about 0.022 Tg of phosphorus to Amazon Rainforest yearly that replenishes the leak of this plant-essential nutrient by rains and flooding, suggesting an important role of Saharan dust in maintaining the productivity of Amazon rainforest on timescales of decades or centuries. We will also discuss seasonal and interannual variations of the dust transport and deposition, and comparisons of the CALIOP-based estimates with model simulations.

  17. Fall Enrollment Report. 2014

    ERIC Educational Resources Information Center

    Iowa Department of Education, 2014

    2014-01-01

    This report summarizes and analyzes fall enrollment in Iowa's community colleges. Each year, Iowa's 15 community colleges submit data on enrollment on the 10th business day of the fall semester. Some highlights from this report include: (1) Fall 2014 enrollment was 93,772 students--a decline of 0.49 percent from last fall; (2) Enrollment continues…

  18. Electrostatic Dust Detector with Improved Sensitivity

    SciTech Connect

    D.P. Boyle, C.H. Skinner, and A. L. Roquemore

    2008-06-09

    Methods to measure the inventory of dust particles and to remove dust if it approaches safety limits will be required in next-step tokamaks such as ITER. An electrostatic dust detector, based on a fine grid of interlocking circuit traces, biased to 30 or 50 V, has been developed for the detection of dust on remote surfaces in air and vacuum environments. Gaining operational experience of dust detection on surfaces in tokamaks is important, however the level of dust generated in contemporary short-pulse tokamaks is comparatively low and high sensitivity is necessary to measure dust on a shot-by-shot basis. We report on modifications in the detection electronics that have increased the sensitivity of the electrostatic dust detector by a factor of up to 120, - a level suitable for measurements on contemporary tokamaks.

  19. Dust cyclone technology for gins – A literature review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dust cyclone research leading to more efficient designs has helped the cotton ginning industry to comply with increasingly stringent air quality regulations governing fine particulate emissions. Future changes in regulations may require additional improvements in dust cyclone efficacy. This inter-...

  20. Saharan Dust Export towards the Caribbean: Dust Sources and Atmospheric Circulation over North Africa

    NASA Astrophysics Data System (ADS)

    Schepanski, Kerstin; Heinold, Bernd; Groß, Silke; Schäfler, Andreas; Weinzierl, Bernadett; Sauer, Daniel; Walser, Adrian; Tegen, Ina

    2015-04-01

    Studies analysing satellite observations illustrate the spatial and temporal distribution of emitting dust sources. Results show that high surface wind speeds related to the break-down of the nocturnal low-level jet (LLJ) occurring during the morning hours are frequent driving mechanism for dust uplift in the Sahara desert. Here, we present a study investigating atmospheric circulation pattern over North Africa favouring (a) dust entrainment into the boundary layer and (b) dust export towards the Caribbean Sea. Satellite-based information on the spatio-temporal distribution of dust source activation (DSA) events inferred from 15-minute Meteosat Second Generation (MSG) Spinning Enhanced Visible and InfraRed Imager (SEVIRI) dust observations are linked to atmospheric circulation regimes over North Africa. By means of air-mass trajectories, which map the dust export from North Africa toward the SALTRACE ground observation site at Barbados, cases are selected which link DSA regions with dust events observed at Barbados. These cases are then examined with regard to the atmospheric conditions during dust emission and geomorphologic dust source characteristic. Dust properties inferred from LIDAR observation using the POLIS system and measurements taken during Falcon research flights are compared to the different dust source locations and atmospheric conditions during dust emission. Altogether, the results from this study aim at illustrating the relevance of knowing the dust source locations in concert with the atmospheric circulation. Ultimately, this study addresses the question of what is finally transported across the Atlantic towards the Caribbean from which dust source region.

  1. Particulate and gaseous organic receptor modeling for the southern California Air Quality Study. Final report

    SciTech Connect

    Watson, J.G.; Chow, J.G.; Lu, Z.; Gertler, A.W.

    1993-11-01

    The Chemical Mass Balance (CMB) receptor model was applied to the chemically-speciated diurnal particulate matter samples and volatile organic compound (VOC) acquired during the summer and fall campaigns of the Southern California Air Quality Study (SCAQS). Source profiles applicable to the Los Angeles area were used to apportion PM[sub (2.5)] and PM[sub (10)] to primary paved road dust, primary construction dust, primary motor vehicle exhaust, primary marine aerosol, secondary ammonium nitrate, and secondary ammonium sulfate. Nonmethane hydrocarbon was apportioned to motor vehicle exhaust, liquid fuel, gasoline vapor, gas leaks, architectural and industrial coatings, and biogenic emissions. Suspended dust was the major contributor to PM(10) during the summer, while secondary ammonium nitrate and primary motor vehicle exhaust contributions were high in the fall. Motor vehicle exhaust was the major contributor to nonmethane hydrocarbons, ranging from 30% to 70% of the total.

  2. Magnetism of outdoor and indoor settled dust and its utilization as a tool for revealing the effect of elevated particulate air pollution on cardiovascular mortality

    NASA Astrophysics Data System (ADS)

    Jordanova, Diana; Jordanova, Neli; Lanos, Philippe; Petrov, Petar; Tsacheva, Tsenka

    2012-08-01

    Settled indoor and outdoor dusts in urban environment represent an important source of secondary pollution. Magnetic characteristics of the settled dust from six cities in Bulgaria are explored, allowing comparison on a national (country) scale. Monthly variations of the mass-specific magnetic susceptibilities (χindoor) and (χoutdoor) and calculated dust loading rates for a period of 17 months do not show seasonal variability, probably due to the dominant role of traffic-related emissions and soil-derived particles in the settled dust. The main magnetic mineral is magnetite, present as spherules and irregular particles of pseudo-single-domain grain sizes. Systematically lower remanence coercivities are obtained for outdoor dusts when compared with the corresponding indoor samples, implying that penetration of smaller particles of ambient origin indoors is the main source of the indoor dust. Mean yearly values of the ratio (χindoor/χoutdoor) for each city show statistically significant correlation with mortality due to cardiovascular diseases. This ratio reveals the source- and site-specific importance of the anthropogenically derived toxicogenic fraction. Heavy metal content of the settled dust is related to the contribution from several pollution sources (soil-derived, combustion and industrial), discriminated through analysis of principal components. SEM/EDX analyses reveal abundant presence of anthopogenic Fe-containing spherules, irregular particles and diesel exhaust conglomerates. High molecular weight polyaromatic hydrocarbons (PAH) dominate the total PAH content of the outdoor dust samples. The observed linear correlation between total PAH content, coercivity of remanence and the ratio Mrs/χ suggest either adsorption of PAHs on iron oxide particles and especially magnetite, or emission related increase in total PAH concentration along with a decrease of effective magnetic grain size of the accompanying magnetic fraction.

  3. Exozodiacal dust

    NASA Astrophysics Data System (ADS)

    Kuchner, Marc Jason

    Besides the sun, the most luminous feature of the solar system is a cloud of "zodiacal" dust released by asteroids and comets that pervades the region interior to the asteroid belt. Similar clouds of dust around other stars---exozodiacal clouds---may be the best tracers of the habitable zones of extra-solar planetary systems. This thesis discusses three searches for exozodiacal dust: (1) We observed six nearby main-sequence stars with the Keck telescope at 11.6 microns, correcting for atmosphere-induced wavefront aberrations and deconvolving the point spread function via classical speckle analysis. We compare our data to a simple model of the zodiacal dust in our own system based on COBE DIRBE observations and place upper limits on the density of exozodiacal dust in these systems. (2) We observed Sirius, Altair, and Procyon with the NICMOS Coronagraph on the Hubble Space Telescope to look for scattered light from exozodiacal dust and faint companions within 10 AU from these stars. (3) The planned nulling capability of the Keck Interferometer should allow it to probe the region <200 milliarcsecond from a bright star and to suppress on-axis starlight by factors of 10 -3 to reveal faint circumstellar material. We model the response of the Keck Interferometer to hypothetical exozodiacal clouds to derive detection limits that account for the effects of stellar leakage, photon noise, noise from null depth fluctuations, and the fact that the cloud's shape is not known a priori. We also discuss the interaction of dust with planets. We used the COBE DIRBE Sky and Zodi Atlas and the IRAS Sky Survey Atlas to search for dynamical signatures of three different planets in the solar system dust complex: (1) We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing Mars. We compare the DIRBE images to a model Mars wake based on the empirical model of the Earth's wake as seen by the DIRBE. (2) We searched the COBE DIRRE Sky and Zodi Atlas for Tiojan dust near

  4. Formation of particulate sulfate and nitrate over the Pearl River Delta in the fall: Diagnostic analysis using the Community Multiscale Air Quality model

    NASA Astrophysics Data System (ADS)

    Qin, Momei; Wang, Xuesong; Hu, Yongtao; Huang, Xiaofeng; He, Lingyan; Zhong, Liuju; Song, Yu; Hu, Min; Zhang, Yuanhang

    2015-07-01

    In recent years, fine particulate matter (PM) pollution and visibility degradation have become severe air quality issues in China. In this study, PM2.5 pollution over the Pearl River Delta (PRD) region during January, April, August, and November 2009 was simulated using the Community Multiscale Air Quality (CMAQ) model. An in-depth diagnostic analysis, focused on November 2009, was also conducted to reveal the patterns of sulfate and nitrate distribution, and to identify the main factors that influence the formation of sulfate and nitrate under typical meteorological conditions. The CMAQ model reasonably reproduced the observed concentrations, but showed better performance for January and November than it did for April and August, for which there was light-moderate underestimation of SO2, NOx, O3, PM10, and PM2.5 concentrations, and slight overestimation of daily 8-h maximum concentrations of O3. Utilizing a sulfate tracking technique, it was found that on nearly 20 days in November 2009, characterized by northeasterly winds, cross-boundary transport contributed to >75% of the total sulfate budget, while local gas phase oxidation and primary emissions averaged 10% and 8%, respectively. Aqueous sulfate typically contributed less than 1% of the total sulfate budget, except when the winds were directed from the sea and high humidity favored aqueous oxidation, and the percentage contribution reached up to 46%. NH3 was generally sufficient to fully neutralize H2SO4; however, the formation of nitrate over the PRD was limited by the availability of NH3.

  5. Status and Future of Dust Storm Forecasting

    NASA Astrophysics Data System (ADS)

    Westphal, D. L.

    2002-12-01

    In recent years, increased attention has been given to the large amounts of airborne dust derived from the deserts and desertified areas of the world and transported over scales ranging from local to global. This dust can have positive and negative impacts on human activities and the environment, including modifying cloud formation, fertilizing the ocean, degrading air quality, reducing visibility, transporting pathogens, and inducing respiratory problems. The atmospheric radiative forcing by the dust has implications for global climate change and presently is one of the largest unknowns in climate models. These uncertainties have lead to much of the funding for research into the sources, properties, and fate of atmospheric dust. As a result of advances in numerical weather prediction over the past decades and the recent climate research, we are now in a position to produce operational dust storm forecasts. International organizations and national agencies are developing programs for dust forecasting. The approaches and applications of dust detection and forecasting are as varied as the nations that are developing the models. The basic components of a dust forecasting system include atmospheric forcing, dust production, and dust microphysics. The forecasting applications include air and auto traffic safety, shipping, health, national security, climate and weather. This presentation will summarize the methods of dust storm forecasting and illustrate the various applications. The major remaining uncertainties (e.g. sources and initialization) will be discussed as well as approaches for solving those problems.

  6. Health risk assessment of migrant workers' exposure to polychlorinated biphenyls in air and dust in an e-waste recycling area in China: Indication for a new wealth gap in environmental rights.

    PubMed

    Wang, Yalin; Hu, Jinxing; Lin, Wei; Wang, Ning; Li, Cheng; Luo, Peng; Hashmi, Muhammad Zaffar; Wang, Wenbo; Su, Xiaomei; Chen, Chen; Liu, Yindong; Huang, Ronglang; Shen, Chaofeng

    2016-02-01

    Migrant workers who work and live in polluted environment are a special vulnerable group in the accelerating pace of urbanization and industrialization in China. In the electronic waste (e-waste) recycling area, for example, migrant workers' exposure to pollutants, such as PCBs (polychlorinated biphenyls), is the result of an informal e-waste recycling process. A village in an electronic waste recycling area where migrant workers gather was surveyed. The migrant workers' daily routines were simulated according to the three-space transition: work place-on the road-home. Indoor air and dust in the migrant workers' houses and workplaces and the ambient air on the roads were sampled. The PCB levels of the air and dust in the places corresponding to the migrant workers are higher than those for local residents. The migrant workers have health risks from PCBs that are 3.8 times greater than those of local residents. This is not only caused by the exposure at work but also by their activity patterns and the environmental conditions of their dwellings. These results revealed the reason for the health risk difference between the migrant workers and local residents, and it also indicated that lifestyle and economic status are important factors that are often ignored compared to occupational exposure. PMID:26641519

  7. Southeastward Dust Transport during the 16-24 March 2006 Asian Dust Event

    NASA Astrophysics Data System (ADS)

    Tsai, F.; Liu, T.; Hsu, S.; Chen, W.; Tu, J.

    2012-04-01

    Synoptic analyses and regional dust models are applied to analyze the dust measurements obtained during the Asian dust events from 16 to 24 March, 2006, in order to understand the controlling mechanism leading to the dust transport far southeastward of the continent. The southeastward transported dust concentrations measured over Taiwan are traced back to their source areas. By tracing the dust loaded air parcels, the synoptic characteristics of the dust event during generation, transport, and dissipation are inspected and compared with an eastward transported event. It has been found that the synoptic mechanism, rather than the emission intensity, leads to the high dust concentration far southeastward off the continent. Most southeastward moving dust clouds are generated behind the surface front in the descent regions and then transported behind a deep lower-level trough, in which the prevailing northerlies or northwesterlies lead to the southeastward dust transported into the tropics. Without a deep lower-level trough, the dust clouds tend to be transported eastward. Surface lidar observations also show descent of the dust concentrations during their southeastward transport. After moving offshore, the anticyclonic circulation in the leading edge of the surface high circulates the dust parcels ahead of the high-pressure center in a southwestward direction towards the seashore off the Southeast China. With the deceleration of the wind speed, the dust clouds then slowly dissipate over the tropics of the Western Pacific, thus providing nutrients to the marine phytoplanktons.

  8. 2-DUST: Dust radiative transfer code

    NASA Astrophysics Data System (ADS)

    Ueta, Toshiya; Meixner, Margaret

    2016-04-01

    2-DUST is a general-purpose dust radiative transfer code for an axisymmetric system that reveals the global energetics of dust grains in the shell and the 2-D projected morphologies of the shell that are strongly dependent on the mixed effects of the axisymmetric dust distribution and inclination angle. It can be used to model a variety of axisymmetric astronomical dust systems.

  9. Dust Devils in Gusev Crater, Sol 463

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a several dust devils -- whirlwinds that loft dust into the air -- moving across a plain below the hillside vantage point of NASA's Mars Exploration Rover Spirit. Several of the dust devils are visible at once in some of the frames in this sequence. The local solar time was about 2 p.m., when the ground temperature was high enough to cause turbulence that kicks up dust devils as the wind blows across the plain. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. Spirit's navigation camera took these images on the rover's 463rd martian day, or sol (April 22, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  10. Large Dust Devil on Horizon, Sol 468

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a large, distant dust devil -- a whirlwind that lofts dust into the air -- as a dark shape on the horizon near the right side of the images. This dust devil was about 5 kilometers (3 miles) away from NASA's Mars Exploration Rover Spirit, and may have been up to 200 meters or yards in diameter. Smaller dust devils closer to the rover appear bright against the dark ground. Spirit's navigation camera took these images on the rover's 468th martian day, or sol (April 27, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  11. Falls in the Elderly

    PubMed Central

    Hodgetts, P. Geoffrey

    1992-01-01

    Falls are a significant cause of morbidity and mortality in the elderly. One in three older people will fall every year. Assessing intrinsic (patient) factors and extrinsic (environmental) factors that increase the risk of falling is an important part of caring for the elderly. Physicians can readily assess balance and mobility as part of a preventive approach. PMID:21221300

  12. Hydrologic and chemical data from selected wells and springs in southern Elmore County, including Mountain Home Air Force Base, southwestern Idaho, Fall 1989

    SciTech Connect

    Parliman, D.J.; Young, H.W.

    1990-01-01

    Hydrologic and chemical data were collected during September through November 1989 from 90 wells and 6 springs in southern Elmore County, southwestern Idaho. These data were collected to characterize the chemical quality of water in major water-yielding zones in areas near Mountain Home and Mountain Home Air Force Base. The data include well and spring locations, well-construction and water level information, and chemical analyses of water from each well and spring inventoried. Groundwater in the study area is generally suitable for most uses. In localized areas, water is highly mineralized, and pH, concentrations of dissolved sulfate, chloride, or nitrite plus nitrate and nitrogen exceed national public drinking-water limits. Fecal coliform and fecal streptococci bacteria were detected in separate water samples. One or more volatile organic compounds were detected in water samples from 15 wells, and the concentration of benzene exceeded the national public drinking-water limit in a water sample from one well. 5 refs., 4 figs., 6 tabs.

  13. Dust Obscures Korea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The dust cloud over eastern Asia was so thick on March 21, 2002, that the Korean Peninsula completely disappeared from view in this Sea-viewing Wide Field-of-view Sensor (SeaWiFS) image of the region. Parts of South Korea report that visibility at the surface is less than 50 m (165 feet). Airports throughout the region canceled flights due to the poor visibility. Eyewitnesses in China report that the dust was so thick in Beijing at times that visibility was limited to 100 m (330 feet), while in parts of the Gansu Province visibility was reported at less than 10 m (33 feet). Chinese officials say this is the worst dust storm to hit in more than 10 years. Dust from an earlier event still colors the air to the east of Japan. (The island of Honshu is just peeking out from under the cloud cover in these images.) Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  14. Chemical composition of tropospheric air masses encountered during high altitude flights (>11.5 km) during the 2009 fall Operation Ice Bridge field campaign

    NASA Astrophysics Data System (ADS)

    Yang, Mei Ying Melissa; Vay, Stephanie A.; Stohl, Andreas; Choi, Yonghoon; Diskin, Glenn S.; Sachse, Glen W.; Blake, Donald R.

    2012-09-01

    As part of the 2009 Operation Ice Bridge campaign, the NASA DC-8 aircraft was used to fill the data-time gap in laser observation of the changes in ice sheets, glaciers and sea ice between ICESat-I (Ice, Cloud, and land Elevation Satellite) and ICESat-II. Complementing the cryospheric instrument payload were four in situ atmospheric sampling instruments integrated onboard to measure trace gas concentrations of CO2, CO, N2O, CH4, water vapor and various VOCs (Volatile Organic Compounds). This paper examines two plumes encountered at high altitude (12 km) during the campaign; one during a southbound transit flight (13°S) and the other at 86°S over Antarctica. The data presented are especially significant as the Southern Hemisphere is heavily under-sampled during the austral spring, with few if any high-resolution airborne observations of atmospheric gases made over Antarctica. Strong enhancements of CO, CH4, N2O, CHCl3, OCS, C2H6, C2H2 and C3H8 were observed in the two intercepted air masses that exhibited variations in VOC composition suggesting different sources. The transport model FLEXPART showed that the 13°S plume contained predominately biomass burning emissions originating from Southeast Asia and South Africa, while both anthropogenic and biomass burning emissions were observed at 86°S with South America and South Africa as indicated source regions. The data presented here show evidence that boundary layer pollution is transported from lower latitudes toward the upper troposphere above the South Pole, which may not have been observed in the past.

  15. Allergies, asthma, and dust

    MedlinePlus

    Allergic rhinitis - dust ... make allergies or asthma worse are called triggers. Dust is a common trigger. When your asthma or allergies become worse due to dust, you are said to have a dust allergy. ...

  16. Mining cosmic dust from the blue ice lakes of Greenland

    NASA Technical Reports Server (NTRS)

    Maurette, M.; Brownlee, D. E.; Fehrenback, L.; Hammer, C.; Jehano, C.; Thomsen, H. H.

    1985-01-01

    Extraterrestrial material, most of which invisible settles to Earth's surface as dust particles smaller than a millimeter in size were investigated. Particles of 1/10 millimeter size fall at a rate of one/sq m/yr collection of extraterrestrial dust is important because the recovered cosmic dust particles can provide important information about comets. Comets are the most important source of dust in the solar system and they are probably the major source of extraterrestrial dust that is collectable at the Earth's surface. A new collection site for cosmic dust, in an environment where degradation by weathering is minimal is reported. It is found that the blue ice lakes on the Greenland ice cap provide an ideal location for collection of extraterrestrial dust particles larger than 0.1 mm in size. It is found that the lakes contain large amounts of cosmic dust which is much better preserved than similar particles recovered from the ocean floor.

  17. The great dust storm of 1986

    NASA Technical Reports Server (NTRS)

    Martin, L. J.; James, P. B.

    1987-01-01

    It is reported that on the global scale, no major dust storm activity was seen during telescopic observations of Mars during the several months or so preceeding this conference. However, the corresponding season on Mars was early fall, which is at the beginning of the dust storm season. It was too early to tell, therefore, if a great dust storm was going to occur that year. Current observations and what they show about present atmospheric conditions and the recession of the South Polar Cap is discussed.

  18. Dust Devil in Gusev Crater, Sol 445

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a single dust devil -- a whirlwind that lofts dust into the air -- about 2 kilometers (1 mile) away, moving across a plain inside Mars' Gusev Crater for several minutes. The dust devil appears in 21 frames. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. The navigation camera on NASA's Mars Exploration Rover Spirit took these images on the rover's 445th martian day, or sol (April 14, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  19. EVALUATION OF FUGITIVE DUST EMISSIONS FROM MINING

    EPA Science Inventory

    This evaluation of fugitive dust air pollution from mining operations identifies and compiles currently available information on emission sources and rates, regulatory approaches, control techniques, measuring and monitoring techniques, health and welfare effects, and research pr...

  20. SMART-COMMIT Observations and Deep-Blue Retrievals of Saharan Dust Properties during NAMMA

    NASA Astrophysics Data System (ADS)

    Tsay, S.; Hsu, N. C.; Ji, Q.; Jeong, M.

    2007-05-01

    Monsoon rainfalls sustain the livelihood of more than half of the world's population. The interaction between natural/anthropogenic aerosols, clouds, and precipitation is a critical mechanism that drives the water cycle and fresh water distribution. Analyses of the long-term trend of July-August precipitation anomaly for the last 50 years in the 20th century depict that the largest regional precipitation deficit occurs over the Sahel, where the monsoon water cycle plays an important role. Thus, it is of paramount importance to study how dust aerosols, as well as air pollution and smoke, influence monsoon variability. The NASA African Monsoon Multidisciplinary Activities (NAMMA) was conducted during the international AMMA Special Observation Period (SOP-3) of September 2006 to better comprehend the key attributes of the Saharan Air Layer (SAL) and how they evolve from the source regions to the Atlantic Ocean. The SAL occurs during the late spring through early fall and originates as a result of low-level convergence induced by heat lows over the Sahara that lifts hot, dry, dust laden air aloft into a well mixed layer that extends up to 500mb. This is crucial for understanding the impact of SAL on the key atmospheric processes that determine precipitation over West Africa and tropical cyclogenesis. Results obtained from the synergy of satellite (Deep-Blue) and surface (SMART-COMMIT) observations will be presented and discussed how the physical, optical and radiative properties of the dust in the SAL evolve from the continental to the marine environment.

  1. SMART-COMMIT Observations and Deep-Blue Retrievals of Saharan Dust Properties during NAMMA

    NASA Technical Reports Server (NTRS)

    Tsay, Si-Chee; Hsu, N. Christina; Ji, Qiang; Jeong, Myeong-Jae

    2007-01-01

    Monsoon rainfalls sustain the livelihood of more than half of the world's population. The interaction between natural/anthropogenic aerosols, clouds, and precipitation is a critical mechanism that drives the water cycle and fresh water distribution. Analyses of the longterm trend of July-August precipitation anomaly for the last 50 years in the 20" century depict that the largest regional precipitation deficit occurs over the Sahel, where the monsoon water cycle plays an important role. Thus, it is of paramount importance to study how dust aerosols, as well as air pollution and smoke, influence monsoon variability. The NASA African Monsoon Multidisciplinary Activities (NAMMA) was conducted during the international AMMA Special Observation Period (SOP-3) of September 2006 to better comprehend the key attributes of the Saharan Air Layer (SAL) and how they evolve from the source regions to the Atlantic Ocean. The SAL occurs during the late spring through early fall and originates as a result of low-level convergence induced by heat lows over the Sahara that lifts hot, dry, dust laden air aloft into a well mixed layer that extends up to 500mb. This is crucial for understanding the impact of SAL on the key atmospheric processes that determine precipitation over West Africa and tropical cyclogenesis. Results obtained from the synergy of satellite (Deep- Blue) and surface (SMART-COMMIT) observations will be presented and discussed how the physical, optical and radiative properties of the dust in the SAL evolve from the continental to the marine environment.

  2. A Mid-Summer's Dust Devil

    NASA Technical Reports Server (NTRS)

    2001-01-01

    One objective for the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) in the Extended Mission is to continue looking for changes and dynamic events taking place on the red planet. The feature shown here elicited gasps of excitement among the MOC Operations Staff when it was received in early April 2001.

    The feature is a dust devil. Dust devils are spinning, columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes. Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars. When this dust devil was spied in Amazonis Planitia on April 10th, the MOC was looking straight down. Usually when the camera is looking down the dust devil will appear as a circular, fuzzy patch with a straight shadow indicating its columnar shape. In this case, however, the dust devil is somewhat curved and kinked--its shape is best seen in the shadow it casts to the right. A thin, light-toned track has been left by the dust devil as it moved eastward across the landscape. Usually, such tracks are darker than the surroundings, in this case the light tone might indicate that the dust being removed by the passing dust devil is darker than the surface underneath the thin veneer of dust.

    Dust devils most typically form when the ground heats up during the day, warming the air immediately above the surface. As the warmed air nearest the surface begins to rise, it spins. The spinning column begins to move across the surface and picks up loose dust (if any is present). The dust makes the vortex visible and gives it the 'dust devil' or tornado-like appearance. This dust devil occurred at an optimal time for dust devils whether on Earth or Mars--around 2 p.m. local time in the middle of Northern Hemisphere Summer. North is up, sunlight illuminates the scene from the left (west), and 500 meters is about 547 yards. The shadow cast by the dust devil goes off the edge of the image, but the length shown

  3. Catching a Falling Star

    NASA Astrophysics Data System (ADS)

    2004-07-01

    . Comets are another important source of meteoroids and perhaps the most spectacular. After many visits near the Sun, a comet "dirty-snowball" nucleus of ice and dust decays and fragments, leaving a trail of meteoroids along its orbit. Some "meteoroid streams" cross the earth's orbit and when our planet passes through them, some of these particles will enter the atmosphere. The outcome is a meteor shower - the most famous being the "Perseids" in the month of August [2] and the "Leonids" in November. Thus, although meteors are referred to as "shooting" or "falling stars" in many languages, they are of a very different nature. More information The research presented in this paper is published in the journal Meteoritics and Planetary Science, Vol. 39, Nr. 4, p. 1, 2004 ("Spectroscopic anatomy of a meteor trail cross section with the ESO Very Large Telescope", by P. Jenniskens et al.). Notes [1] The team is composed of Peter Jenniskens (SETI Institute, USA), Emmanuël Jehin (ESO), Remi Cabanac (Pontificia Universidad Catolica de Chile), Christophe Laux (Ecole Centrale de Paris, France), and Iain Boyd (University of Michigan, USA). [2] The maximum of the Perseids is expected on August 12 after sunset and should be easily seen.

  4. Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust

    PubMed Central

    Perera, Inoka E.; Sapko, Michael J.; Harris, Marcia L.; Zlochower, Isaac A.; Weiss, Eric S.

    2015-01-01

    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. PMID:26834390

  5. Reuyl Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2002-01-01

    't the Alps, you will find quite a few avalanches. Avalanches of dust, however, not snow. Martian dust can become so thick in this area that it eventually slides down the steep slopes, creating runaway avalanches of dust. No dedicated, Swiss-like avalanche rescue teams would be needed much on Mars, however. Unlike snow, the dust doesn't pile up and accumulate at the bottom. Instead, dust particles are so small that they get launched into the atmosphere where they remain suspended until . . . poof! They are blown away and distributed lightly elsewhere. For evidence of past avalanches, check out the dark streaks running down the bright, sunlit slopes (western side of the peaks about 1/3 of the way down the image). These avalanche scars are dark because the underlying surface is not as bright as the removed dust. Eventually, new dust will settle over these scars, and the streaks will brighten until they fade into the background. The neat thing is that we'll be able to see all of these changes happening over time. Our current two Mars orbiters (called Mars Global Surveyor and 2001 Mars Odyssey) are showing that avalanche action is happening right now, all of the time on Mars. For example, the camera on Mars Global Surveyor has already taken pictures of the Martian surface in some areas that showed no avalanches - the first time the picture was snapped, that is. The next time around, the camera took a picture of the same area, only voila! New streaks, meaning new avalanches! That's why it can be so exciting to look at the Martian landscape over time to see how it changes. The THEMIS camera on Odyssey will continue to map out the places where the avalanches occur and how often. This information will really help scientists understand how dust is works to shape the terrain and to influence the Martian climate as it constantly swings into the atmosphere, falls down to the ground, and rises back up again. Stay tuned to see if you too can pick out the changes over time!

  6. African dust phosphorus fertilizing the Amazon and the Atlantic Ocean is derived from marine sediments and igneous rocks - no indication for Bodélé diatomite contribution

    NASA Astrophysics Data System (ADS)

    Gross, Avner; Castido, Danilo; Pio, Casimero; Angert, Alon

    2013-04-01

    Dust eroded from West Africa is blown across the Atlantic Ocean towards the tropics and constitutes a major external source of phosphorus (P) to the Amazon and marine surface waters. It is usually assumed that the P concentration in dust is ~700 µg P g/dust based on the average concentrations in crust material. In addition, previous studies have claimed that diatomites from the Bodélé depression in Chad are a major source of P to the equatorial Atlantic Ocean and the Amazon. In this study we have utilized the oxygen isotopes in resin extractable inorganic phosphate (δ18OP) of dust particles to identify their P sources. The data presented here is from over 100 PM10 dust samples, collected during major dust events in October- April 2011 and 2012, as part of the CV-DUST project in Cape-Verde. This archipelago is located downwind of the Sahara and Sahel dust producing areas, and is thus well suited for collecting dust blown out from Africa. Air mass back trajectories computations show that the dust origin can be classified to 3 sectors: the north and west Saharan sector, south and central Saharan sector and the Sahel sector. Dust particles approaching from these 3 sectors shows distinct resin-P concentrations (in the range of 1160 µg P g/dust to 7260 µg P g/dust) and distinct δ18OP values which ranges from 7.2‰ to 21.7‰. Major elements concentrations also showed distinct pattern. Dust particles approaching from the north and west Saharan sector shows the lowest P concentrations and a δ18OP values of ~21‰ which are typical for P originating from marine sediments at the Sahara area. Dust particles from the south west Saharan sector are richest in P and have the lowest δ18OP values of 7.2‰ , which are typical for P originated from igneous source. Dust approaching from the Sahel sector shows mid-range P concentrations and δ18OP values of ~14‰ , and fall on isotopic mixing line (R2=0.91) between the dust samples with igneous and marine sedimentary

  7. Atmospheric transport of mold spores in clouds of desert dust

    USGS Publications Warehouse

    Shinn, E.A.; Griffin, Dale W.; Seba, D.B.

    2003-01-01

    Fungal spores can be transported globally in clouds of desert dust. Many species of fungi (commonly known as molds) and bacteria--including some that are human pathogens--have characteristics suited to long-range atmospheric transport. Dust from the African desert can affect air quality in Africa, Europe, the Middle East, and the Americas. Asian desert dust can affect air quality in Asia, the Arctic, North America, and Europe. Atmospheric exposure to mold-carrying desert dust may affect human health directly through allergic induction of respiratory stress. In addition, mold spores within these dust clouds may seed downwind ecosystems in both outdoor and indoor environments.

  8. Numerical Prediction of Dust. Chapter 10

    NASA Technical Reports Server (NTRS)

    Benedetti, Angela; Baldasano, J. M.; Basart, S.; Benincasa, F.; Boucher, O.; Brooks, M.; Chen, J. P.; Colarco, P. R.; Gong, S.; Huneeus, N.; Jones, L; Lu, S.; Menut, L.; Mulcahy, J.; Nickovic, S.; Morcrette, J.-J.; Perez, C.; Reid, J. S.; Sekiyama, T. T.; Tanaka, T.; Terradellas, E.; Westphal, D. L.; Zhang, X.-Y.; Zhou, C.-H.

    2013-01-01

    Covers the whole breadth of mineral dust research, from a scientific perspective Presents interdisciplinary work including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies Explores the role of dust as a player and recorder of environmental change This volume presents state-of-the-art research about mineral dust, including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies. Dust research is a new, dynamic and fast-growing area of science and due to its multiple roles in the Earth system, dust has become a fascinating topic for many scientific disciplines. Aspects of dust research covered in this book reach from timescales of minutes (as with dust devils, cloud processes, and radiation) to millennia (as with loess formation and oceanic sediments), making dust both a player and recorder of environmental change. The book is structured in four main parts that explore characteristics of dust, the global dust cycle, impacts of dust on the Earth system, and dust as a climate indicator. The chapters in these parts provide a comprehensive, detailed overview of this highly interdisciplinary subject. The contributions presented here cover dust from source to sink and describe all the processes dust particles undergo while travelling through the atmosphere. Chapters explore how dust is lifted and transported, how it affects radiation, clouds, regional circulations, precipitation and chemical processes in the atmosphere, and how it deteriorates air quality. The book explores how dust is removed from the atmosphere by gravitational settling, turbulence or precipitation, how iron contained in dust fertilizes terrestrial and marine ecosystems, and about the role that dust plays in human health. We learn how dust is observed, simulated using computer models and forecast. The book also details the role of dust deposits for climate reconstructions

  9. Dust vertical distribution in the Caribbean during the Puerto Rico Dust Experiment

    NASA Astrophysics Data System (ADS)

    Reid, Jeffrey S.; Westphal, Douglas L.; Livingston, John M.; Savoie, Dennis L.; Maring, Hal B.; Jonsson, Haflidi H.; Eleuterio, Daniel P.; Kinney, James E.; Reid, Elizabeth A.

    2002-04-01

    As part of Puerto Rico Dust Experiment (PRIDE), a Piper Navajo research aircraft, equipped with particle probes and an airborne Sun photometer, was deployed to Puerto Rico in July 2000. During the study, mid-visible optical depths in Puerto Rico due to dust reached 0.5. In the middle of the summer transport season, the vertical distributions of dust were similar to that commonly assumed in the region with dust concentrated in the Saharan Air Layer (SAL) aloft. However, during the first half of the study period, dust had the highest concentrations in the marine and convective boundary layers, with lower dust concentrations above the trade inversion despite the presence of a strong SAL. Supporting meteorology suggests that the state of the monsoon on the coast of Africa influences the nature of the vertical distribution of dust in the Caribbean.

  10. Nepheline rock dust pneumoconiosis: a report of 2 cases

    SciTech Connect

    Olscamp, G.; Herman, S.J.; Weisbrod, G.L.

    1982-01-01

    Two cases of nepheline rock dust pneumoconiosis are presented. Radiologically, this is seen as a diffuse increase in interstitial lung markings, lymphadenopathy air-space disease, and atelectasis secondary to extrinsic compression by enlarged hilar lymph nodes. Major differential diagnoses include carcinoma of the lung, sarcoidosis, and interstitial lung disease caused by other inorganic dusts. Nepheline rock dust pneumoconiosis should be considered when the above radiological changes are observed and an occupational exposure to inorganic dust is documented.

  11. Nepheline rock dust pneumoconiosis. A report of 2 cases

    SciTech Connect

    Olscamp, G.; Herman, S.J.; Weisbrod, G.L.

    1982-01-01

    Two cases of nepheline rock dust pneumoconiosis are presented. Radiologically, this is seen as a diffuse increase in interstitial lung markings, lymphadenopathy, air-space disease, and atelectasis secondary to extrinsic compression by enlarged hilar lymph nodes. Major differential diagnoses include carcinoma of the lung, sarcoidosis, and interstitial lung disease caused by other inorganic dusts. Nepheline rock dust pneumoconiosis should be considered when the above radiological changes are observed and an occupational exposure to inorganic dust is documented.

  12. Fall Leaf Portraits

    ERIC Educational Resources Information Center

    O'Hara, Cristina

    2012-01-01

    In this article, the author describes how students can create a stunning as well as economical mosaic utilizing fall's brilliantly colored leaves, preserved at their peak in color. Start by choosing a beautiful fall day to take students on a nature walk to collect a variety of leaves in different shapes, sizes, and colors. Focus on collecting a…

  13. First Aid: Falls

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Falls KidsHealth > For Parents > First Aid: Falls Print A A A Text Size en ... Floors, Doors & Windows, Furniture, Stairways: Household Safety Checklist First Aid: Broken Bones Head Injuries Preventing Children's Sports Injuries ...

  14. Experiments in Free Fall

    ERIC Educational Resources Information Center

    Art, Albert

    2006-01-01

    A model lift containing a figure of Albert Einstein is released from the side of a tall building and its free fall is arrested by elastic ropes. This arrangement allows four simple experiments to be conducted in the lift to demonstrate the effects of free fall and show how they can lead to the concept of the equivalence of inertial and…

  15. Fall armyworm migration patterns.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), infestations in most of North America arise from annual migrations of populations that overwinter in southern Texas and Florida. Cytochrome Oxidase I haplotype profiles within the fall armyworm corn-strain, the subgroup tha...

  16. Learning From Falling

    ERIC Educational Resources Information Center

    Joh, Amy, S.; Adolph, Karen, E.

    2006-01-01

    Walkers fall frequently, especially during infancy. Children (15, 21, 27, 33, and 39 month-olds) and adults were tested in a novel foam pit paradigm to examine age-related changes in the relationship between falling and prospective control of locomotion. In trial 1, participants walked and fell into a deformable foam pit marked with distinct…

  17. Uranium mill ore dust characterization

    SciTech Connect

    Knuth, R.H.; George, A.C.

    1980-11-01

    Cascade impactor and general air ore dust measurements were taken in a uranium processing mill in order to characterize the airborne activity, the degree of equilibrium, the particle size distribution and the respirable fraction for the /sup 238/U chain nuclides. The sampling locations were selected to limit the possibility of cross contamination by airborne dusts originating in different process areas of the mill. The reliability of the modified impactor and measurement techniques was ascertained by duplicate sampling. The results reveal no significant deviation from secular equilibrium in both airborne and bulk ore samples for the /sup 234/U and /sup 230/Th nuclides. In total airborne dust measurements, the /sup 226/Ra and /sup 210/Pb nuclides were found to be depleted by 20 and 25%, respectively. Bulk ore samples showed depletions of 10% for the /sup 226/Ra and /sup 210/Pb nuclides. Impactor samples show disequilibrium of /sup 226/Ra as high as +-50% for different size fractions. In these samples the /sup 226/Ra ratio was generally found to increase as particle size decreased. Activity median aerodynamic diameters of the airborne dusts ranged from 5 to 30 ..mu..m with a median diameter of 11 ..mu..m. The maximum respirable fraction for the ore dusts, based on the proposed International Commission on Radiological Protection's (ICRP) definition of pulmonary deposition, was < 15% of the total airborne concentration. Ore dust parameters calculated for impactor duplicate samples were found to be in excellent agreement.

  18. Possible influence of dust on hurricane genesis

    NASA Astrophysics Data System (ADS)

    Bretl, Sebastian; Reutter, Philipp; Raible, Christoph C.; Ferrachat, Sylvaine; Lohmann, Ulrike

    2014-05-01

    Tropical Cyclones (TCs) belong to the most extreme events in nature. In the past decade, the possible impact of dust on Atlantic hurricanes receives growing interest. As mineral dust is able to absorb incoming solar radiation and therefore warm the surrounding air, the presence of dust can lead to a reduction of sea surface temperature (SST) and an increase in atmospheric stability. Furthermore, resulting baroclinic effects and the dry Saharan easterly jet lead to an enhanced vertical shear of the horizontal winds. SST, stability, moisture and vertical wind shear are known to potentially impact hurricane activity. But how Saharan dust influences these prerequisites for hurricane formation is not yet clear. Some dynamical mechanisms induced by the SAL might even strengthen hurricanes. An adequate framework for investigating the possible impact of dust on hurricanes is comparing high resolution simulations (~0.5°x0.5°, 31 vertical levels) with and without radiatively active dust aerosols. To accomplish this task, we are using the general circulation model ECHAM6 coupled to a modified version of the aerosol model HAM, ECHAM6-HAM-Dust. Instead of the five aerosol species HAM normally contains, the modified version takes only insoluble dust into account, but modifies the scavenging parameters in order to have a similar lifetime of dust as in the full ECHAM6-HAM. All remaining aerosols are prescribed. To evaluate the effects of dust on hurricanes, a TC detection and tracking method is applied on the results. ECHAM6-HAM-Dust was used in two configurations, one with radiatively active dust aerosols and one with dust being not radiatively active. For both set-ups, 10 Monte-Carlo simulations of the year 2005 were performed. A statistical method which identifies controlling parameters of hurricane genesis was applied on North Atlantic developing and non-developing disturbances in all simulations, comparing storms in the two sets of simulations. Hereby, dust can be assigned

  19. Pre-impact fall detection.

    PubMed

    Hu, Xinyao; Qu, Xingda

    2016-01-01

    Pre-impact fall detection has been proposed to be an effective fall prevention strategy. In particular, it can help activate on-demand fall injury prevention systems (e.g. inflatable hip protectors) prior to fall impacts, and thus directly prevent the fall-related physical injuries. This paper gave a systematical review on pre-impact fall detection, and focused on the following aspects of the existing pre-impact fall detection research: fall detection apparatus, fall detection indicators, fall detection algorithms, and types of falls for fall detection evaluation. In addition, the performance of the existing pre-impact fall detection solutions were also reviewed and reported in terms of their sensitivity, specificity, and detection/lead time. This review also summarized the limitations in the existing pre-impact fall detection research, and proposed future research directions in this field. PMID:27251528

  20. 30 CFR 57.22106 - Dust containing volatile matter (I-C mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Dust containing volatile matter (I-C mines). 57... Dust containing volatile matter (I-C mines). Dust containing volatile matter shall not be allowed to..., if suspended in air, would become an explosive mixture. An explosive mixture of dust...

  1. A critical evaluation of combustible/explosible dust testing methods-part 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tests were conducted by the Center for Agricultural Air Quality Engineering and Science (CAAQES) and by Safety Consulting Engineers Inc. (SCE) to determine if dust found in cotton gins (gin dust) would serve as fuel for dust explosions. In other words, is gin dust explosible? The laboratory tests us...

  2. Dust Studies in DIII-D and TEXTOR

    SciTech Connect

    Rudakov, D L; Litnovsky, A; West, W P; Yu, J H; Boedo, J A; Bray, B D; Brezinsek, S; Brooks, N H; Fenstermacher, M E; Groth, M; Hollmann, E M; Huber, A; Hyatt, A W; Krasheninnikov, S I; Lasnier, C J; Moyer, R A; Pigarov, A Y; Philipps, V; Pospieszczyk, A; Smirnov, R D; Sharpe, J P; Solomon, W M; Watkins, J G; Wong, C C

    2009-02-17

    Studies of naturally occurring and artificially introduced carbon dust are conducted in DIII-D and TEXTOR. In DIII-D, dust does not present operational concerns except immediately after entry vents. Submicron sized dust is routinely observed using Mie scattering from a Nd:Yag laser. The source is strongly correlated with the presence of Type I edge localized modes (ELMs). Larger size (0.005-1 mm diameter) dust is observed by optical imaging, showing elevated dust levels after entry vents. Inverse dependence of the dust velocity on the inferred dust size is found from the imaging data. Direct heating of the dust particles by the neutral beam injection (NBI) and acceleration of dust particles by the plasma flows are observed. Energetic plasma disruptions produce significant amounts of dust. Large flakes or debris falling into the plasma may result in a disruption. Migration of pre-characterized carbon dust is studied in DIII-D and TEXTOR by introducing micron-size dust in plasma discharges. In DIII-D, a sample holder filled with {approx}30 mg of dust is introduced in the lower divertor and exposed to high-power ELMing H-mode discharges with strike points swept across the divertor floor. After a brief exposure ({approx}0.1 s) at the outer strike point, part of the dust is injected into the plasma, raising the core carbon density by a factor of 2-3 and resulting in a twofold increase of the radiated power. In TEXTOR, instrumented dust holders with 1-45 mg of dust are exposed in the scrape-off layer 0-2 cm radially outside of the last closed flux surface in discharges heated with neutral beam injection (NBI) power of 1.4 MW. At the given configuration of the launch, the dust did not penetrate the core plasma and only moderately perturbed the edge plasma, as evidenced by an increase of the edge carbon content.

  3. Injuries sustained by falls.

    PubMed Central

    Rozycki, G S; Maull, K I

    1991-01-01

    During a recent 4-year period, 381 patients were admitted with injuries sustained from falls. Equal numbers of patients were less than and greater than 50 years of age and included 53 children (less than or equal to 16 years) and 214 elderly (greater than or equal to 55 years). Falls from heights occurred predominantly in young males (mean age 34.2 years), were most commonly job or recreation related and resulted in higher injury severity scores (ISS). Falls in the elderly occurred more commonly in women, typically on a flat surface, and were less severe. Despite lower mean ISS, fall victims over 55 years of age had longer hospitalizations (11.4 vs. 4.5 days) and incurred higher hospital charges compared to younger patients. There were 35 deaths (9.2%). In patients under 55 years, deaths resulted from fall-related central nervous system (CNS) injury and/or multisystem trauma. In patients over 55 years, fatalities were most commonly related to pre-existent medical conditions. Based on a review of this experience, we conclude that: (1) unlike other causes of blunt and penetrating trauma, both sexes are equally at risk from fall-related injuries but sex incidence is age related; (2) falls from heights are more common in men; (3) advanced age and pre-existing medical conditions account for the increased morbidity and mortality following falls and; (4) cost containment measures for fall-related trauma must consider not only injury severity, but the age and pre-existent medical conditions of the patient. PMID:1772536

  4. 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.

  5. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... air contamination level less than 0.05 milligram per cubic meter and against radionuclides;...

  6. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... air contamination level less than 0.05 milligram per cubic meter and against radionuclides;...

  7. 42 CFR 84.1152 - Silica dust loading test; respirators designed as protection against dusts, fumes, and mists...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Silica dust loading test; respirators designed as protection against dusts, fumes, and mists having an air contamination level less than 0.05 milligram per... air contamination level less than 0.05 milligram per cubic meter and against radionuclides;...

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

    NASA Astrophysics Data System (ADS)

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

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

  9. Measurement of nicotine in household dust

    SciTech Connect

    Kim, Sungroul Aung, Ther; Berkeley, Emily; Diette, Gregory B.; Breysse, Patrick N.

    2008-11-15

    An analytical method of measuring nicotine in house dust was optimized and associations among three secondhand smoking exposure markers were evaluated, i.e., nicotine concentrations of both house dust and indoor air, and the self-reported number of cigarettes smoked daily in a household. We obtained seven house dust samples from self-reported nonsmoking homes and 30 samples from smoking homes along with the information on indoor air nicotine concentrations and the number of cigarettes smoked daily from an asthma cohort study conducted by the Johns Hopkins Center for Childhood Asthma in the Urban Environment. House dust nicotine was analyzed by isotope dilution gas chromatography-mass spectrometry (GC/MS). Using our optimized method, the median concentration of nicotine in the dust of self-reported nonsmoking homes was 11.7 ng/mg while that of smoking homes was 43.4 ng/mg. We found a substantially positive association (r=0.67, P<0.0001) between house dust nicotine concentrations and the numbers of cigarettes smoked daily. Optimized analytical methods showed a feasibility to detect nicotine in house dust. Our results indicated that the measurement of nicotine in house dust can be used potentially as a marker of longer term SHS exposure.

  10. Dust agglomeration

    NASA Technical Reports Server (NTRS)

    2000-01-01

    John Marshall, an investigator at Ames Research Center and a principal investigator in the microgravity fluid physics program, is studying the adhesion and cohesion of particles in order to shed light on how granular systems behave. These systems include everything from giant dust clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, dust, and powders that we encounter or use on a daily basis. Marshall investigated electrostatic charge in microgravity on the first and second U.S. Microgravity Laboratory shuttle missions to see how grains aggregate, or stick together. With gravity's effects eliminated on orbit, Marshall found that the grains of sand that behaved ever so freely on Earth now behaved like flour. They would just glom together in clumps and were quite difficult to disperse. That led to an understanding of the prevalence of the electrostatic forces. The granules wanted to aggregate as little chains, like little hairs, and stack end to end. Some of the chains had 20 or 30 grains. This phenomenon indicated that another force, what Marshall believes to be an electrostatic dipole, was at work.(The diagram on the right emphasizes the aggregating particles in the photo on the left, taken during the USML-2 mission in 1995.)

  11. Canyon Dust

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03682 Canyon Dust

    These dust slides are located on the wall of Thithonium Chasma.

    Image information: VIS instrument. Latitude -4.1N, Longitude 275.7E. 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.

  12. Dust Slides

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03677 Linear Clouds

    Dust slides are common in the dust covered region called Lycus Sulci. A large fracture is also visible in this image.

    Image information: VIS instrument. Latitude 28.1N, Longitude 226.3E. 18 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.

  13. U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR EXTRACTION OF METALS FROM SOIL, DUST, AIR FILTER, AND SURFACE AND DERMAL WIPE SAMPLES FOR AA (GRAPHITE FURNACE OR FLAME) OR ICP-AES ANALYSIS (BCO-L-3.1)

    EPA Science Inventory

    The purpose of this SOP is to describe the acid digestion of soil, house dust, air filter, and surface or dermal wipe samples for analysis using inductively coupled plasma atomic emissions spectrometry (ICP-AES) and/or graphite furnace atomic absorption spectrometry (GFAAS) or fl...

  14. Survival of falling robots

    NASA Technical Reports Server (NTRS)

    Cameron, Jonathan M.; Arkin, Ronald C.

    1992-01-01

    As mobile robots are used in more uncertain and dangerous environments, it will become important to design them so that they can survive falls. In this paper, we examine a number of mechanisms and strategies that animals use to withstand these potentially catastrophic events and extend them to the design of robots. A brief survey of several aspects of how common cats survive falls provides an understanding of the issues involved in preventing traumatic injury during a falling event. After outlining situations in which robots might fall, a number of factors affecting their survival are described. From this background, several robot design guidelines are derived. These include recommendations for the physical structure of the robot as well as requirements for the robot control architecture. A control architecture is proposed based on reactive control techniques and action-oriented perception that is geared to support this form of survival behavior.

  15. Osteoporosis: Preventing Falls

    MedlinePlus

    ... of this page please turn Javascript on. Feature: Osteoporosis Preventing Falls Past Issues / Winter 2011 Table of ... next to your bed Free NIH Videos About Osteoporosis The NIHSeniorHealth Web site features five brief, informative ...

  16. Editors' Fall Picks

    ERIC Educational Resources Information Center

    Hoffert, Barbara; Heilbrun, Margaret; Kuzyk, Raya; Kim, Ann; McCormack, Heather; Katterjohn, Anna; Burns, Ann; Williams, Wilda

    2008-01-01

    From the fall's cascade of great new books, "Library Journal's" editors select their favorites--a dark rendition of Afghan life, a look at the "self-esteem trap," a celebration of Brooklyn activism, and much more.

  17. Survival of falling robots

    NASA Astrophysics Data System (ADS)

    Cameron, Jonathan M.; Arkin, Ronald C.

    1992-02-01

    As mobile robots are used in more uncertain and dangerous environments, it will become important to design them so that they can survive falls. In this paper, we examine a number of mechanisms and strategies that animals use to withstand these potentially catastrophic events and extend them to the design of robots. A brief survey of several aspects of how common cats survive falls provides an understanding of the issues involved in preventing traumatic injury during a falling event. After outlining situations in which robots might fall, a number of factors affecting their survival are described. From this background, several robot design guidelines are derived. These include recommendations for the physical structure of the robot as well as requirements for the robot control architecture. A control architecture is proposed based on reactive control techniques and action-oriented perception that is geared to support this form of survival behavior.

  18. Siena, 1794: History's Most Consequential Meteorite Fall

    NASA Astrophysics Data System (ADS)

    Marvin, U. B.

    1995-09-01

    In the mythos of meteoritics, the fall of stones at L'Aigle in Normandy at 1 p. m. on April 26, 1803, is commonly regarded as the event that turned skeptics into believers and opened the way for the new science. A strong case can be made, however, that the fall of stones at Siena at 7:00 p.m. on June 16, 1794, established the authenticity of meteorite falls and set in motion the reexaminations of entrenched beliefs that led to the founding of the new science. The Siena fall was heralded by the appearance of an extraordinarily high, dark cloud emitting smoke, sparks like rockets, and bolts of unusually slow-moving red lightning. With a tremendous explosion a shower of stones, ranging in weight from a few milligrams to 3 kg, fell southeast of Siena. This was the first meteorite fall to occur in the vicinity of a sizeable European city and the first to be witnessed by so many people, including English visitors, that the fall of the stones from the sky could not be denied. It also was the first fall to be seriously investigated by scholars, at several universities in Italy, who collected eye-witness reports and specimens and formulated hypotheses of origin. Their task was greatly complicated by the timing of the fall which occurred 18 hours after Mt. Vesuvius sprang into full eruption. Some believed that the two events were entirely coincidental; others thought that the stones either were ejecta from the volcano (which lay about 320 km to the southeast of Siena) or had consolidated in the fiery masses of dust and ash expelled by the mountain. No explanations seemed entirely satisfactory, but, in an age when the very possibility of falling stones had been decisively ruled out by savants of the Enlightenment, the well-observed fall at Siena opened a new dialog on this subject. The Siena fall occurred only two months after the publication in Riga and Leipzig of Ernst F. F. Chladni's book On the Origin of Ironmasses in which he concluded from historical records that

  19. Dust Storm Hits Canary Islands

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A thick pall of sand and dust blew out from the Sahara Desert over the Atlantic Ocean yesterday (January 6, 2002), engulfing the Canary Islands in what has become one of the worst sand storms ever recorded there. In this scene, notice how the dust appears particularly thick in the downwind wake of Tenerife, the largest of the Canary Islands. Perhaps the turbulence generated by the air currents flowing past the island's volcanic peaks is churning the dust back up into the atmosphere, rather than allowing it to settle toward the surface. This true-color image was captured by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on January 7, 2002. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  20. Interstellar Dust: Contributed Papers

    NASA Technical Reports Server (NTRS)

    Tielens, Alexander G. G. M. (Editor); Allamandola, Louis J. (Editor)

    1989-01-01

    A coherent picture of the dust composition and its physical characteristics in the various phases of the interstellar medium was the central theme. Topics addressed included: dust in diffuse interstellar medium; overidentified infrared emission features; dust in dense clouds; dust in galaxies; optical properties of dust grains; interstellar dust models; interstellar dust and the solar system; dust formation and destruction; UV, visible, and IR observations of interstellar extinction; and quantum-statistical calculations of IR emission from highly vibrationally excited polycyclic aromatic hydrocarbon (PAH) molecules.

  1. Effects of airborne dust collected from Kuwait on human erythrocytes

    SciTech Connect

    Siddiqui, S.M.; Khan, S.A.; Ahmad, S.; Beg, M.U.

    1992-01-01

    Air borne dust as deposited on air conditioner's filter was collected from most polluted regions of Kuwait and for comparison also from Dubai. Kuwait dust samples were found to contain high concentrations of Ni, Mn and Pb and a number of organic compounds different from the oil samples collected from the oil pool in the oil fields. Toxicity evaluation against human erythrocytes showed strong hemolytic nature of the dust. Treatment of erythrocytes with the dust exhibited peroxidative damage of the membrane. The dust collected from Dubai was innocuous. The present data suggest that erythrocyte damaging potential of the dust can be used as a marker of toxicity and provide information about the dissipation of toxic factors from airborne dust with time. 15 refs., 2 figs., 3 tabs.

  2. Dust events, pulmonary diseases and immune system

    PubMed Central

    Esmaeil, Nafiseh; Gharagozloo, Marjan; Rezaei, Abbas; Grunig, Gabriele

    2014-01-01

    Incidences of sand storms have increased in recent years and there is evidence that these dusts can move across long distances. Sand dusts have different adverse effects on health, but one of the most important of them is pulmonary disease. After inhalation of dust, many dust particles are moved to the airways. Dust particles can be sensed by airways epithelial cells, activate macrophages, dendritic cells and innate immune cells and then initiate responses in various populations of specific immune cells such as T helper cells subsets (Th1, Th2, Th17), T cytotoxic cells and B cells. Initiation of inflammatory immune responses, activation of immune cells and releases of many cytokines, chemokines and other inflammatory molecules, have variable pathologic affects on lung in different respiratory diseases. Unfortunately control of desert dusts is more difficult than control of air pollution. For prevention and treatment of respiratory diseases that are caused by desert dusts, researchers need well-designed epidemiological studies, combined with analysis of the precise composition of sand dusts, and the precise mechanisms of the immune responses. Recognizing the exact cellular and molecular immune mechanisms would be very useful to find new approaches for treatment of desert dust associated pulmonary diseases. PMID:24660118

  3. Effects of large-scale Amazon forest degradation on climate and air quality through fluxes of carbon dioxide, water, energy, mineral dust and isoprene.

    PubMed

    Betts, Richard; Sanderson, Michael; Woodward, Stephanie

    2008-05-27

    Loss of large areas of Amazonian forest, through either direct human impact or climate change, could exert a number of influences on the regional and global climates. In the Met Office Hadley Centre coupled climate-carbon cycle model, a severe drying of this region initiates forest loss that exerts a number of feedbacks on global and regional climates, which magnify the drying and the forest degradation. This paper provides an overview of the multiple feedback process in the Hadley Centre model and discusses the implications of the results for the case of direct human-induced deforestation. It also examines additional potential effects of forest loss through changes in the emissions of mineral dust and biogenic volatile organic compounds. The implications of ecosystem-climate feedbacks for climate change mitigation and adaptation policies are also discussed. PMID:18267906

  4. Dust studies in DIII-D and TEXTOR

    SciTech Connect

    Rudakov, D.L.; Litnovsky, A; West, W. P.; Yu, J.H.; Boedo, J.A.; McLean, Adam G

    2009-01-01

    Studies of naturally occurring and artificially introduced carbon dust are conducted in DIII-D and TEXTOR. In DIII-D, dust does not present operational concerns except immediately after entry vents. Submicrometre sized dust is routinely observed using Mie scattering from a Nd: Yag laser. The source is strongly correlated with the presence of type I edge localized modes (ELMs). Larger size (0.005-1 mm diameter) dust is observed by optical imaging, showing elevated dust levels after entry vents. Inverse dependence of the dust velocity on the inferred dust size is found from the imaging data. Heating of the dust particles by the neutral beam injection (NBI) and acceleration of dust particles by the plasma flows are observed. Energetic plasma disruptions produce significant amounts of dust; on the other hand, large flakes or debris falling into the plasma may induce a disruption. Migration of pre-characterized carbon dust is studied in DIII-D and TEXTOR by introducing micrometre-size particles into plasma discharges. In DIII-D, a sample holder filled with 30-40 mg of dust is inserted in the lower divertor and exposed, via sweeping of the strike points, to the diverted plasma flux of high-power ELMing H-mode discharges. After a brief dwell (similar to 0.1 s) of the outer strike point on the sample holder, part of the dust penetrates into the core plasma, raising the core carbon density by a factor of 2-3 and resulting in a twofold increase in the radiated power. In TEXTOR, instrumented dust holders with 1-45 mg of dust are exposed in the scrape-off-layer 0-2 cm radially outside of the last closed flux surface in discharges heated with 1.4 MW of NBI. Launched in this configuration, the dust perturbed the edge plasma, as evidenced by a moderate increase in the edge carbon content, but did not penetrate into the core plasma.

  5. Atmospheric microbiology in the northern Caribbean during African dust events

    USGS Publications Warehouse

    Griffin, Dale W.; Kellogg, C.A.; Garrison, V.H.; Lisle, J.T.; Borden, T.C.; Shinn, E.A.

    2003-01-01

    Between July 2000 and August 2001 forty-three air samples were collected in the northern Caribbean: Twenty-six in the US Virgin Islands, and 17 samples aboard ship during two 1-week cruises. Samples were collected during African dust events and non-dust conditions and screened for the presence of culturable bacteria and fungi. A total of 3,652 liters of air were collected during non-dust conditions, with 19 bacteria and 28 fungi being recovered. During dust conditions a total of 2,369 liters of air were screened resulting in the recovery of 171 bacteria and 76 fungi. A statistically significant difference was found between the two data sets. These results support previous African dust research and further demonstrate that dust particles can serve as a vessel for the global dispersion of bacteria and fungi. Dustborne microorganisms may play a significant role in the ecology and health of downwind ecosystems.

  6. Turbulence Modeling in Dust Forming Media

    NASA Astrophysics Data System (ADS)

    Helling, Ch.; Lüttke, M.; Sedlmayr, E.; Oeverman, M.; Klein, R.

    The process of dust formation is considered in a turbulent medium. The modeling for hydro- and thermodynamics follows the classical approach for an inviscid, compressible fluid and the dust formation process is described as a two step process, nucleation and growth, including element conservation. Our approach is to combine asymptotic techniques and multi-dimensional direct numerical simulations (DNS). The turbulence modeling will be performed by the simulation of regime-wise increased scales allowing for a detailed study of the corresponding behavior of the dust forming gas flow. Our investigations have been started in the microscopic scale regime (Kolmogoroff scale << lref << density scale height) where acoustic waves are continuously generated by turbulent motions caused by large-scale convection. We show that the local gas temperature can fall below a temperature threshold for efficient dust nucleation by the superposition of acoustic expansion waves. As the formed seed particles subsequently grow, radiation cooling is intensified causing new dust to form and a runaway effect sets in. An asymptotic model serves as an independent test of our DNS results and allows an investigation of the long term behavior of our dust forming system. Adopting the example of a brown dwarf atmosphere, intermittent dust distributions in space and time (clouds) are predicted by asymptotic calculations of stochastic acoustic interaction and have been studied further by 1D and 2D DNS.

  7. Global potential of dust devil occurrence

    NASA Astrophysics Data System (ADS)

    Jemmett-Smith, Bradley; Marsham, John; Knippertz, Peter; Gilkeson, Carl

    2014-05-01

    Mineral dust is a key constituent in the climate system. Airborne mineral dust forms the largest component of the global aerosol budget by mass and subsequently affects climate, weather and biogeochemical processes. There remains large uncertainty in the quantitative estimates of the dust cycle. Dry boundary-layer convection serves as an effective mechanism for dust uplift, typically through a combination of rotating dust devils and non-rotating larger and longer-lived convective plumes. These microscale dry-convective processes occur over length scales of several hundred metres or less. They are difficult to observe and model, and therefore their contribution to the global dust budget is highly uncertain. Using an analytical approach to extrapolate limited observations, Koch and Renno (2006) suggest that dust devils and plumes could contribute as much as 35%. Here, we use a new method for quantifying the potential of dust devil occurrence to provide an alternative perspective on this estimate. Observations have shown that dust devil and convective plume occurrence is favoured in hot arid regions under relatively weak background winds, large ground-to-air temperature gradients and deep dry convection. By applying such known constraints to operational analyses from the European Centre for Medium Range Weather Forecasts (ECMWF), we provide, to the best of the authors' knowledge, the first hourly estimates of dust devil occurrence including an analysis of sensitivity to chosen threshold uplift. The results show the expected diurnal variation and allow an examination of the seasonal cycle and day-to-day variations in the conditions required for dust devil formation. They confirm that desert regions are expected to have by far the highest frequency of dry convective vortices, with winds capable of dust uplift. This approach is used to test the findings of Koch and Renno (2006). Koch J., Renno N. (2006). The role of convective plumes and vortices on the global aerosol

  8. Dust Measurements in Tokamaks

    SciTech Connect

    Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M

    2008-04-23

    Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

  9. Dust storm events over Delhi: verification of dust AOD forecasts with satellite and surface observations

    NASA Astrophysics Data System (ADS)

    Singh, Aditi; Iyengar, Gopal R.; George, John P.

    2016-05-01

    Thar desert located in northwest part of India is considered as one of the major dust source. Dust storms originate in Thar desert during pre-monsoon season, affects large part of Indo-Gangetic plains. High dust loading causes the deterioration of the ambient air quality and degradation in visibility. Present study focuses on the identification of dust events and verification of the forecast of dust events over Delhi and western part of IG Plains, during the pre-monsoon season of 2015. Three dust events have been identified over Delhi during the study period. For all the selected days, Terra-MODIS AOD at 550 nm are found close to 1.0, while AURA-OMI AI shows high values. Dust AOD forecasts from NCMRWF Unified Model (NCUM) for the three selected dust events are verified against satellite (MODIS) and ground based observations (AERONET). Comparison of observed AODs at 550 nm from MODIS with NCUM predicted AODs reveals that NCUM is able to predict the spatial and temporal distribution of dust AOD, in these cases. Good correlation (~0.67) is obtained between the NCUM predicted dust AODs and location specific observations available from AERONET. Model under-predicted the AODs as compared to the AERONET observations. This may be mainly because the model account for only dust and no anthropogenic activities are considered. The results of the present study emphasize the requirement of more realistic representation of local dust emission in the model both of natural and anthropogenic origin, to improve the forecast of dust from NCUM during the dust events.

  10. Free fall of a cat—freshman physics exercise

    NASA Astrophysics Data System (ADS)

    Studnička, Filip; Šlégr, Jan; Štegner, David

    2016-07-01

    This paper describes theoretical calculation of the terminal velocity of falling cat, taking the air drag into account. The results show that a fall from the seventh floor is critical for the cat so we introduce a new quantity called the ‘coefficient of the cat’s fear’ during free fall. A subsequent experiment with a model of a cat carrying the accelerometer confirmed this conclusion. This calculation and experiment can act as a strong motivational factor during introductory physics courses.

  11. Fugitive dust emission source profiles and assessment of selected control strategies for particulate matter at gravel processing sites in Taiwan.

    PubMed

    Chang, Chang-Tang; Chang, Yu-Min; Lin, Wen-Yinn; Wu, Ming-Ching

    2010-10-01

    Particles emitted from gravel processing sites are one contributor to worsening air quality in Taiwan. Major pollution sources at gravel processing sites include gravel and sand piles, unpaved roads, material crushers, and bare ground. This study analyzed fugitive dust emission characteristics at each pollution source using several types of particle samplers, including total suspended particulates (TSP), suspended particulate (PM10), fine suspended particulate (PM2.5), particulate sizer, and dust-fall collectors. Furthermore, silt content and moisture in the gravel were measured to develop particulate emission factors. The results showed that TSP (< 100 microm) concentrations at the boundary of gravel sites ranged from 280 to 1290 microg/m3, which clearly exceeds the Taiwan hourly air quality standard of 500 microg/m3. Moreover, PM10 concentrations, ranging from 135 to 550 microg/m3, were also above the daily air quality standard of 125 microg/m3 and approximately 1.2 and 1.5 times the PM2.5 concentrations, ranging from 105 to 470 microg/m3. The size distribution analysis reveals that mass mean diameter and geometric standard deviation ranged from 3.2 to 5.7 microm and from 2.82 to 5.51, respectively. In this study, spraying surfactant was the most effective control strategy to abate windblown dust from unpaved roads, having a control efficiency of approximately 93%, which is significantly higher than using paved road strategies with a control efficiency of approximately 45%. For paved roads, wet suppression provided the best dust control efficiencies ranging from 50 to 83%. Re-vegetation of disturbed ground had dust control efficiencies ranging from 48 to 64%. PMID:21090554

  12. EVALUATION OF A NEW METHOD OF DUST CONTROL

    PubMed Central

    Harris, M. Coleman; Shure, Norman

    1952-01-01

    Microscopic dust sampling was done to determine the amount of dust in the homes of six patients who were sensitive to house dust and who had allergic disease that was intractable to treatment. One case was subsequently excluded from the study because of extraordinary circumstances. The remaining five cases were studied with repeated dust counts before and after a water-and-oil emulsion was sprayed in the patient's bedroom to immobilize house dust. In all five cases, the patients had dramatic relief of symptoms after the spraying was done. In four out of five, there was concomitant reduction of the amount of dust in the air as determined by microscopic counting of the dust particles on a glycerincoated slide. In the fifth case, relief of symptoms was not accompanied by reduction of dust on slides, but investigation revealed an error in control of exposure of the slides. PMID:14886758

  13. Simulating Dust Cycling during the Late Paleozoic Ice Age

    NASA Astrophysics Data System (ADS)

    Heavens, N. G.; Mahowald, N. M.; Soreghan, G. S.; Soreghan, M. J.; Shields, C. A.; Albani, S.

    2012-12-01

    Upper Carboniferous and Lower Permian strata preserve evidence for significant deposition of mineral dust, an aerosol with strong potential influence on the climate. Some equatorial marine carbonate records from this interval appear to record massive influxes of fine dust (diameter < 10 μm) after rapid sea level fall, suggesting that the pacing of dust deposition was connected to the expansion and contraction of ice sheets during the important icehouse climate interval of Carboniferous and Permian time. Nearby continental strata record high accumulations of coarse dust (loess) during periods of increasing aridity (apparent glacial intervals) and of fine dust (paleosols) during periods of increasing humidity (apparent interglacial intervals), though the pacing of this deposition may be more strongly associated with orbital forcing than ice sheet dynamics. Significant dust deposition continued in many of these areas during the emergence of the Earth's climate from icehouse conditions during Middle Permian time. Understanding the dynamics of dust cycling during the depths of the icehouse is the first step to investigating dust records from the most recent icehouse termination of Earth's history. Here, we attempt to reconstruct the cycling and some of the potential climate impacts of mineral dust during this interval, using version 3 of the Community Climate System Model (CCSM3) and the best available records of dust deposition. Modeled sensitivity simulations suggest that climatic controls on dust cycling that act on relatively short timescales (primarily meteorological and vegetation-related) cannot explain the large variability in dust deposition rates inferred from marine carbonate records. Processes acting on longer timescales, particularly those that control the availability of wind-erodible sediment, likely are more important. We also consider whether exposure of sedimentary basins during sea level fall and glaciogenic dust production could modulate dust

  14. Terminal Velocity of a Shuttlecock in Vertical Fall.

    ERIC Educational Resources Information Center

    Peastrel, Mark; And Others

    1980-01-01

    Describes a straightforward vertical fall experiment using a badminton shuttlecock, a tape measure, and a millisecond timer. The effects of air resistance are important and directly measurable. The experimental data best fit a predictive model which assumes a resistive force quadratic in the instantaneous speed of the falling object. (GS)

  15. RELATIVE CONGENER SCALING OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS TO ESTIMATE BUILDING FIRE CONTRIBUTIONS IN AIR, SURFACE WIPES, AND DUST SAMPLES

    EPA Science Inventory

    EPA collected ambient air samples in lower Manhattan for about nine months following the September 11, 2001 (9/11) World Trade Center (WTC) attacks. Measurements were made of a host of airborne contaminants including volatile organic compounds (VOCs), polycyclic aromatic hydroca...

  16. Experiments on Injection of Dust Jets into Plasma

    SciTech Connect

    Dubinov, Alexander E.; Lvov, Igor L.; Sadovoi, Sergey A.; Selemir, Victor D.; Vyalykh, Dmitry V.

    2005-10-31

    Experimental technique for studying the injection of dust jets into plasma of a glow discharge in air based on a needle injector is developed. The velocity and flight time of a dust jet is measured under different initial conditions by laser method. Imprints of dust jets on adhesive films are obtained. It is shown that the propagation of 20-{mu}m dust grains in plasma is accompanied by self-contraction instability along and across the discharge, which leads to the dust agglomeration.

  17. Glass Frit Clumping And Dusting

    SciTech Connect

    Steimke, J. L.

    2013-09-26

    DWPF mixes a slurry of glass frit (Frit 418) and dilute (1.5 wt%) formic acid solution with high level waste in the Slurry Mix Evaporator (SME). There would be advantages to introducing the frit in a non-slurry form to minimize water addition to the SME, however, adding completely dry frit has the potential to generate dust which could clog filters or condensers. Prior testing with another type of frit, Frit 320, and using a minimal amount of water reduced dust generation, however, the formation of hard clumps was observed. To examine options and behavior, a TTQAP [McCabe and Stone, 2013] was written to initiate tests that would address these concerns. Tests were conducted with four types of glass frit; Frit 320, DWPF Frit 418, Bekeson Frit 418 and Multi-Aspirator Frit 418. The last two frits are chemically identical to DWPF Frit 418 but smaller particles were removed by the respective vendors. Test results on Frit Clumping and Dusting are provided in this report. This report addresses the following seven questions. Short answers are provided below with more detailed answers to follow. 1. Will the addition of a small amount of water, 1.5 wt%, to dry DWPF Frit 418 greatly reduce the dust generation during handling at DWPF? a. Yes, a small scale test showed that adding a little water to the frit greatly reduced dust generation during handling. 2. Will the addition of small amounts of water to the frit cause clumping that will impair frit handling at DWPF? a. No, not with Frit 418. Although clumps were observed to form when 1.5 wt% water was mixed with DWPF Frit 418, then compressed and air-dried overnight, the clumps were easily crushed and did not form the hardened material noted when Frit 320 was tested. 3. What is the measured size distribution of dust generated when dry frit is handled? (This affects the feasibility and choice of processing equipment for removing the dust generating fraction of the frit before it is added to the SME.) a. The size distribution for

  18. Dust feed mechanism

    DOEpatents

    Milliman, Edward M.

    1984-01-01

    The invention is a dust feed device for delivery of a uniform supply of dust for long periods of time to an aerosolizing means for production of a dust suspension. The device utilizes at least two tandem containers having spiral brushes within the containers which transport the dust from a supply to the aerosolizer means.

  19. Aeolian dust as a transport hazard

    NASA Astrophysics Data System (ADS)

    Baddock, M. C.; Strong, C. L.; Murray, P. S.; McTainsh, G. H.

    2013-06-01

    The effects of blowing dust on transport operations are often mentioned as one of the significant impacts of aeolian processes on human welfare. However, few studies have been presented to demonstrate this impact. This research examined official air traffic incident reports in Australia for inclusively 1969-2010 to characterise the hazard of blowing dust to aviation in the country, the first such study of its kind. For the 42 year record, 61 incidents were identified (mean 1.4 per annum), with the large majority occurring in the first half of the 1970s. Only 20% of incidents occurred from 1984 onwards. Australian dust activity has not decreased over time, and the reduction in incidents is partly explained by improvements in aviation technology. The centralisation of Air Traffic Control operations to major coastal cities may however have reduced pilot reporting of dust-induced aviation incidents. By type of dust activity, dust storms were associated with nearly half of the reported incidents and dust hazes produced around a quarter. Only 5% of incidents resulted in any physical damage to aircraft and only one case involving personal injury was reported. The majority of the adverse effects on aviation due to dust (nearly 60% of reported incidents) were related to difficulties for navigation and completion of scheduled journey. Since aircraft damage and bodily harm were rare, the impact of dust in Australia is mostly that of inconvenience and associated raised economic costs. From 1990, the temporal pattern of incidents does not show any significant increase despite several intensely dusty years associated with recent droughts. This suggests that Australian aviation safety may be relatively resistant to the adverse effects of atmospheric dust as a hazard.

  20. Electric Dust Devils and Dust Storms

    NASA Astrophysics Data System (ADS)

    Renno, N. O.; Yana, C.

    2004-12-01

    Electrical fields measurements in terrestrial dust devils show that they maintain tremendous charge separation and that their electric fields exceeds the breakdown potential (~10 kV/m) of the Martian atmosphere (Farrell et al., 2002, 2003; Krauss et al., 2002; Renno et al., 2004). Typical Martian dust devils are be up to 100 times larger and much stronger than the small terrestrial analogues. Martian dust devils have higher dust content and may produce even stronger electrical fields. Indeed, the dust devils observed in the Pathfinder images have about 700 times the dust content of the local background atmosphere (Metzger et al., 1999). Thus, strong charge separations and electric-field breakdown are likely to occur on Martian dust devils and dust storms. Our theory (Renno et al., 2004) and laboratory experiments in a Mars chamber shows that collisions between sand and dust particles produce non-thermal microwave radiation. The non-thermal microwave emission allows not only the indirect detection of electric activity but also the determination of the physical properties of Martian sand and dust by remote sensing. Besides being geologically important, electrically charged Martian dust devils and dust storms are potential hazards to Landers and will be dangerous to future astronauts exploring its surface. Indeed, the design of adequate mechanical and electrical systems for these Landers cannot progress effectively without a better understanding of Martian dust devils and dust storms. Moreover, ancillary phenomena associated with electrically charged vortices can ionize atmospheric gases and might have important implications for atmosphere chemistry and even habitability.

  1. Lunar dust: The Hazard and Astronaut Exposure Risks

    NASA Astrophysics Data System (ADS)

    Cain, John R.

    2010-12-01

    This paper reviews the characterisation of lunar dust or regolith, the toxicity of the dust and associated health effects, the techniques for assessing the health risks from dust exposure and describes the measures used or being developed to mitigate exposure. Lunar dust is formed from micrometeorite impacts onto the Moon's surface. The hypervelocity impacts result in communition and the formation of sharp and clingy agglutinates. The dust particles vary in size with the smallest being less than 10 μm. If the chemical reactive particles are deposited in the lungs, they may cause respiratory disease. During lunar exploration, the astronaut's spacesuits will become contaminated with lunar dust. The dust will be released into the atmosphere when the suits are removed. The exposure risks to health will need to be assessed by relating to a permissible exposure limit. During the Apollo missions, the astronauts were exposed to lunar dust. Acute health effects from dust inhalation exposure included sore throat, sneezing and coughing. Long-term exposure to the dust may cause a more serious respiratory disease similar to silicosis. On future missions the methods used to mitigate exposure will include providing high air recirculation rates in the airlock, the use of a "Double Shell Spacesuit" so that contaminated spacesuits are removed before entering the airlock, the use of dust shields to prevent dust accumulating on surfaces, the use of high gradient magnetic separation to remove surface dust and the use of solar flux to sinter and melt the regolith around the spacecraft.

  2. Urban dust in the Guanzhong basin of China, part II: A case study of urban dust pollution using the WRF-Dust model.

    PubMed

    Li, Nan; Long, Xin; Tie, Xuexi; Cao, Junji; Huang, Rujin; Zhang, Rong; Feng, Tian; Liu, Suixin; Li, Guohui

    2016-01-15

    We developed a regional dust dynamical model (WRF-Dust) to simulate surface dust concentrations in the Guanzhong (GZ) basin of China during two typical dust cases (19th Aug. and 26th Nov., 2013), and compared model results with the surface measurements at 17 urban and rural sites. The important improvement of the model is to employ multiple high-resolution (0.5-500 m) remote sensing data to construct dust sources. The new data include the geographic information of constructions, croplands, and barrens over the GZ basin in summer and winter of 2013. For the first time, detailed construction dust emissions have been introduced in a regional dust model in large cities of China. Our results show that by including the detailed dust sources, model performance at simulating dust pollutions in the GZ basin is significantly improved. For example, the simulated dust concentration average for the 17 sites increases from 28 μg m(-3) to 59 μg m(-3), closing to the measured concentration of 66 μg m(-3). In addition, the correlation coefficient (r) between the calculated and measured dust concentrations is also improved from 0.17 to 0.57, suggesting that our model better presents the spatial variation. Further analysis shows that urban construction activities are the crucial source in controlling urban dust pollutions. It should be considered by policy makers for mitigating particulate air pollution in many Chinese cities. PMID:26475241

  3. African Dust Aerosols as Atmospheric Ice Nuclei

    NASA Technical Reports Server (NTRS)

    DeMott, Paul J.; Brooks, Sarah D.; Prenni, Anthony J.; Kreidenweis, Sonia M.; Sassen, Kenneth; Poellot, Michael; Rogers, David C.; Baumgardner, Darrel

    2003-01-01

    Measurements of the ice nucleating ability of aerosol particles in air masses over Florida having sources from North Africa support the potential importance of dust aerosols for indirectly affecting cloud properties and climate. The concentrations of ice nuclei within dust layers at particle sizes below 1 pn exceeded 1/cu cm; the highest ever reported with our device at temperatures warmer than homogeneous freezing conditions. These measurements add to previous direct and indirect evidence of the ice nucleation efficiency of desert dust aerosols, but also confirm their contribution to ice nuclei populations at great distances from source regions.

  4. The role of unbalanced mesoscale circulations in dust storms

    NASA Astrophysics Data System (ADS)

    Kaplan, Michael L.; Vellore, Ramesh K.; Lewis, John M.; Young, Matthew

    2011-12-01

    In this study, two dust storms in northwestern Nevada (February 2002 and April 2004) are investigated through the use of Weather Research and Forecasting (WRF) model simulations. The focus of the study is twofold: (1) Examination of dynamic processes on the meso-β scale for both cases, and (2) analysis of extreme upper-air cooling prior to storm formation and the development of a nearly discontinuous gust front in the 2002 case that could not be validated in an earlier synoptic-scale study. Results of the simulations suggest that the driving mechanism for dust storm dynamics derives from the breakdown and subsequent balance between the advection of geostrophic wind and total wind in the exit region of the polar jet. In this process, the deviation from quasi-geostrophic (Q-G) balance creates a plume of ascent along and to the right of the jet's exit region. The cold pool generation in the mid-lower troposphere in consequence of this adjustment sets up the kinetic energy in the planetary boundary layer and creates a forward leaning (slope from north to south) cold front under the jet exit region. Surface heating is coupled with this frontal structure, and rapid surface pressure falls (rises) occur initially (later) in response to diabatic (adiabatic) processes. The adjustments occur at fast time scales, scales that are radically different from those in studies that followed the Q-G tenets of the Danielsen paradigm. The results of this study indicate that meso-β scale features associated with subgeostrophy in the exit region of the curved jet aloft and associated thermal wind imbalance (700-500 hPa) lead to significant velocity divergence aloft. Mass/momentum adjustments and the associated cooling strengthen the baroclinic zone aloft. The restoration to thermal wind balance accompanying this cooling resulted in a narrow zone of surface pressure rise and strong low-level isallobaric winds. The turbulent momentum for dust ablation comes from this sequence of processes.

  5. Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Crater wall dust avalanches in southern Arabia Terra.

    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.

    Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (335.5 West). 19 meter/pixel resolution.

  6. Dust particle dynamics in atmospheric dust devils

    NASA Astrophysics Data System (ADS)

    Izvekova, Yulia; Popel, Sergey

    2016-04-01

    Dust particle dynamics is modeled in the Dust Devils (DDs). DD is a strong, well-formed, and relatively long-lived whirlwind, ranging from small (half a meter wide and a few meters tall) to large (more than 100 meters wide and more than 1000 meters tall) in Earth's atmosphere. We develop methods for the description of dust particle charging in DDs, discuss the ionization processes in DDs, and model charged dust particle motion. Our conclusions are consistent with the fact that DD can lift a big amount of dust from the surface of a planet into its atmosphere. On the basis of the model we perform calculations and show that DDs are important mechanism for dust uplift in the atmospheres of Earth and Mars. Influence of DD electric field on dynamics of dust particles is investigated. It is shown that influence of the electric field on dust particles trajectories is significant near the ground. At some altitude (more then a quarter of the height of DD) influence of the electric field on dust particles trajectories is negligible. For the calculation of the dynamics of dust electric field can be approximated by effective dipole located at a half of the height of DD. This work was supported by the Russian Federation Presidential Program for State Support of Young Scientists (project no. MK-6935.2015.2).

  7. Wind modeling of Chihuahuan Desert dust outbreaks

    NASA Astrophysics Data System (ADS)

    Rivera Rivera, Nancy I.; Gill, Thomas E.; Gebhart, Kristi A.; Hand, Jennifer L.; Bleiweiss, Max P.; Fitzgerald, Rosa M.

    The Chihuahuan Desert region of North America is a significant source of mineral aerosols in the Western Hemisphere, and Chihuahuan Desert dust storms frequently impact the Paso del Norte (El Paso, USA/Ciudad Juarez, Mexico) metropolitan area. A statistical analysis of HYSPLIT back trajectory residence times evaluated airflow into El Paso on all days and on days with synoptic (non-convective) dust events in 2001-2005. The incremental probability—a measure of the areas most likely to have been traversed by air masses arriving at El Paso during dusty days—was only strongly positively associated with the region west-southwest of the city, a zone of known dust source areas. Focused case studies were made of major dust events on 15 April and 15 December 2003. Trajectories approached the surface and MM5 (NCAR/Penn State Mesoscale Model) wind speeds increased at locations consistent with dust sources observed in satellite imagery on those dates. Back trajectory and model analyses suggested that surface cyclones adjacent to the Chihuahuan Desert were associated with the extreme dust events, consistent with previous studies of dust storms in the Southern High Plains to the northeast. The recognition of these meteorological patterns serves as a forecast aid for prediction of dust events likely to impact the Paso del Norte.

  8. Student Enrollments, Fall 1995.

    ERIC Educational Resources Information Center

    Arkansas State Dept. of Higher Education, Little Rock.

    This document presents demographic information about enrollment at public and independent institutions of higher education in Arkansas as of fall 1995. A listing of abbreviations for the public four-year, public two-year, and independent institutions is followed by a map of their locations. An executive summary identifies highlights such as the…

  9. Falling into Winter.

    ERIC Educational Resources Information Center

    Harrington, Carolyn Lang

    2000-01-01

    Presents an activity that connects art, science, and nature in which elementary school students learn about deciduous trees. Explains that students create a torn-tissue collage, using fall colors for a background and drawing a silhouette of a tree without leaves on top of the background with black crayon. (CMK)

  10. Editors' Fall Picks

    ERIC Educational Resources Information Center

    Heilbrun, Margaret; McCormack, Heather; Katterjohn, Anna; Kuzyk, Raya; Roncevic, Mirela; Fox, Bette-Lee; Hoffert, Barbara

    2009-01-01

    "Library Journal's" review editors select fall titles readers won't want to miss--"Waiting on a Train: The Embattled Future of Passenger Rail Service" (James McCommons); "Happy" (Alex Lemon); "Free for All: Joe Papp, the Public, and the Greatest Theater Story Ever Told" (Kenneth Turan & Joseph Papp); "In My Father's Shadow: A Daughter Remembers…

  11. Fall 2013 International Comparisons

    ERIC Educational Resources Information Center

    Northwest Evaluation Association, 2014

    2014-01-01

    This Fall report is an aggregated statistical analysis of Measures of Academic Progress® (MAP®) data from international schools. The report provides a consistent means of comparisons of specific sub-groups by subject and grade, which allows partners to compare their MAP® results with other schools within their region or membership organization.…

  12. The News, Fall 2002.

    ERIC Educational Resources Information Center

    Giles, Ray, Ed.

    2002-01-01

    This fall 2002 newsletter from the Community College League of California contains several articles, news stories, and the brochure from the 2002 Annual Convention, "Celebrating the Way California LEARNS." Articles include: (1) "Nursing Shortage Poses Dilemma for Colleges: Access vs. Efficiency," a discussion of the debate over how to increase the…

  13. Freshmen Survey. Fall 1985.

    ERIC Educational Resources Information Center

    Goodyear, Don

    In 1985, College of the Sequoias (COS) was asked by the Cooperative Institutional Research Program (conducted jointly by the American Council on Education and the University of California, Los Angeles) to participate in a survey of incoming freshmen for the fall 1985 semester. During the summer counseling session, 259 new COS freshmen were…

  14. 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 (

  15. Detection of anthropogenic dust using CALIPSO lidar measurements

    NASA Astrophysics Data System (ADS)

    Huang, J. P.; Liu, J. J.; Chen, B.; Nasiri, S. L.

    2015-10-01

    Anthropogenic dusts are those produced by human activities on disturbed soils, which are mainly cropland, pastureland, and urbanized regions, and are a subset of the total dust load which includes natural sources from desert regions. Our knowledge of anthropogenic dusts is still very limited due to a lack of data. To understand the contribution of anthropogenic dust to the total global dust load, it is important to identify it apart from total dust. In this study, a new technique for distinguishing anthropogenic dust from natural dust is proposed by using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) dust and planetary boundary layer (PBL) height retrievals along with a land use data set. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Results reveal that local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 25 % of the global continental dust load. Of these anthropogenic dust aerosols, more than 53 % come from semi-arid and semi-wet regions. Annual mean anthropogenic dust column burden (DCB) values range from 0.42 g m-2, with a maximum in India, to 0.12 g m-2, with a minimum in North America. A better understanding of anthropogenic dust emission will enable us to focus on human activities in these critical regions and with such knowledge we will be more able to improve global dust models and to explore the effects of anthropogenic emission on radiative forcing, climate change, and air quality in the future.

  16. Detection of anthropogenic dust using CALIPSO lidar measurements

    NASA Astrophysics Data System (ADS)

    Huang, J.; Liu, J.; Chen, B.; Nasiri, S. L.

    2015-04-01

    Anthropogenic dusts are those produced by human activities on disturbed soils, which are mainly cropland, pasture, and urbanized regions and are a subset of the total dust load which includes natural sources from desert regions. Our knowledge of anthropogenic dusts is still very limited due to a lack of data on source distribution and magnitude, and on their effect on radiative forcing which may be comparable to other anthropogenic aerosols. To understand the contribution of anthropogenic dust to the total global dust load and its effect on radiative transfer and climate, it is important to identify them from total dust. In this study, a new technique for distinguishing anthropogenic dust from natural dust is proposed by using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) dust and planetary boundary layer (PBL) height retrievals along with a land use dataset. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Results reveal that local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 25% of the global continental dust load. Of these anthropogenic dust aerosols, more than 53% come from semi-arid and semi-wet regions. Annual mean anthropogenic dust column burden (DCB) values range from 0.42 g m-2 with a maximum in India to 0.12 g m-2 with a minimum in North America. A better understanding of anthropogenic dust emission will enable us to focus on human activities in these critical regions and with such knowledge we will be better able to improve global dust models and to explore the effects of anthropogenic emission on radiative forcing, climate change and air quality in the future.

  17. Direct observations of the atmospheric processing of Asian mineral dust

    NASA Astrophysics Data System (ADS)

    Sullivan, R. C.; Guazzotti, S. A.; Sodeman, D. A.; Prather, K. A.

    2006-05-01

    The accumulation of secondary acid products and ammonium on individual mineral dust particles during ACE-Asia has been measured in real-time using ATOFMS. Changes in the amounts of sulphate, nitrate, and chloride mixed with dust particles corresponded to different air mass source regions. During volcanically influenced periods, dust mixed with sulphate dominated. This rapidly switched to dust predominantly mixed with chloride when the first Asian dust front reached the R/V Ronald Brown. We hypothesise that the high degree of mixing of dust with chloride was caused by the prior reaction of NOy(g) and volcanic SO2(g) with sea salt particles, reducing the availability of nitrate and sulphate precursors while releasing HCl(g), which then reacted with the incoming dust front. The segregation of sulphate from nitrate and chloride in individual dust particles is demonstrated for the first time. This is likely caused by the dust plume encountering elevated SO2(g) in the Chinese interior before reaching coastal urban areas polluted by both SO2(g) and NOx(g). This caused the fractions of dust mixed with nitrate and/or chloride to be strongly dependent on the total dust loadings, whereas dust mixed with sulphate did not show this same dust concentration dependence. Ammonium was also significantly mixed with dust and the amount correlated strongly with the total amount of secondary acid reaction products in the dust. Submicron dust and ammonium sulphate were internally mixed, contrary to frequent statements that they exist as an external mixture. The size distribution of the mixing state of dust with these secondary species validates previous models and mechanisms of the atmospheric processing of dust. The uptake of secondary acids was also dependent on the individual dust particle mineralogy; nitrate accumulated on calcium-rich dust while sulphate accumulated on aluminosilicate-rich dust. Oxidation of S(IV) to S(VI) by iron in the aluminosilicate-rich dust is a probable

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  19. Gusev Dust Devil Movie, Sol 459 (Enhanced)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 459th martian day, or sol (April 18, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera, and the contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    The images were processed in three steps. All images were calibrated to remove known camera artifacts. The images were then processed to remove stationary objects. The result is a gray scene showing only features that change with time. The final step combined the original image with the image that shows only moving features, showing the martian scene and the enhanced dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface

  20. Gusev Dust Devil Movie, Sol 456 (Enhanced)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 456th martian day, or sol (April 15, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera, and the contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    The images were processed in three steps. All images were calibrated to remove known camera artifacts. The images were then processed to remove stationary objects. The result is a gray scene showing only features that change with time. The final step combined the original image with the image that shows only moving features, showing the martian scene and the enhanced dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface

  1. The role of entrainment by falling raindrops in microbursts

    NASA Technical Reports Server (NTRS)

    Krueger, Steven K.

    1988-01-01

    The numerical model of Krueger et al. (1986) for dry microburst simulations is used to study the role of entrainment by falling raindrops. Two series of numerical simulations were conducted: a control series, and a series with the raindrop fall speed set to zero so that the rain moved with the air instead of falling through it. The results show that entrainment due to falling raindrops helps microbursts with large raindrop mixing ratios to form in stable stratifications. It is found that entrainment appears to contribute to the small spatial and temporal scales that characterize microburst outflows.

  2. Cosmic dust and the comet connection

    NASA Astrophysics Data System (ADS)

    Knacke, R.

    1984-09-01

    Spacecraft flybys, direct collection at earth, and new instrumentation for earth-based telescopes may soon make it possible to interpret the physical and chemical properties of fine cometary dust particles. Spectral studies have shown that a comet's diffuse curved tail reveals a solar spectrum probably due to sunlight reflected by particles approximately one micron in size. Model studies have shown that a distant comet may be a solid mixture of ices and granular rocky material without a tail. As the comet approaches the sun, longer infrared wavelengths reflect falling dust temperatures, and only silicates seem to emit strongly. The dust may be mainly made up of Si with Mg and Fe, and O. The rest of the nucleus may be composed of H2O, CO2, CO and perhaps CH4 and NH3. Interplanetary dust collected by the Helios spacecraft reveals a low density, fragile structure, and chemical analysis of bright meteors shows a similarity to carbonaceous chondrites. Because of interstellar dust resembling in some aspects the silicate structure of comets, and because these particles are found in regions of recent star formation, the question is raised whether comets containing this dust could be forming at such locations. Missions to Halley's comet in 1986 by ESA's Giotto spacecraft, and the Soviet Union's Vega spacecraft are outlined.

  3. Impact Produced and Mobilized Dust in the Martian Atmosphere

    NASA Astrophysics Data System (ADS)

    Nemtchinov, I. V.; Shuvalov, V. V.; Greeley, R.

    2001-12-01

    The objective of this work is to study possible mechanisms of new dust production and existing dust entrainment after impacts of meteoroids onto Mars and to assess the possible relationship to dust clouds. We use detailed numerical simulations based on the SOVA multi-dimensional multi-material hydrocode [1]. In the first run of simulations, partially described in [2], only the dust ejected from the crater was taken into account. In the process of ejection soil density decreases near the cavity boundary. At the moment when the density falls below some critical value the solid material is replaced by a set of discrete particles (dust, boulders) of equivalent mass [3]. The distribution of particles by sizes was taken according experimental data obtained in the course of large-scale TNT and nuclear explosions on the Earth's ground [4]. The radius of impactor was varied from 1 to 100 m. The lowest value corresponds to high strength meteoroids passing through the rarefied Martian atmosphere without substantial fragmentation and deceleration. The impact velocity was taken to be 11 and 20 km/s. In all the variants the mass of the dust ejected from the forming craters was about 10 M, where M is the impactor mass. It was suggested [5] that the dust may be mobilized even if the impactor does not reach the ground surface. To check this idea the code was modified to take into account blast produced impulsive winds blowing the preexisting dust from the surface by mechanism similarly to that of the stationary winds [6]. Turbulent viscosity and diffusion were taken into acount. Some portions of dust are deposited on the surface due to gravity. The particles striking the surface increase a flux of the suspended dust. The saltation thresholds were taken according [7-8]. For a 1 m radius stony asteroid releasing its energy (0.15 kt TNT) at an altitude of about 100 m above the surface after first two seconds the mass of the dust in the air was 3.5 M, and after 15 s it decreased to 2

  4. "Dust Devils": Gardening Agents on the Surface of Mars, and Hidden Hazards to Human Exploration?

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Smith, P.; White, B.; Farrell, W.

    1999-01-01

    Dust devils are familiar sites in the and regions of the world: they can produce quite spectacular displays of dust lofting when the vortices scavenge very loose dust from a dry lake bed or from recently disturbed agricultural fields. If one were to arrive at the center of an arid region, take one photograph, or even a series of photographs over a period of several days, then return the images for laboratory analysis, it would be most likely concluded that the region was inactive from an aeolian perspective. No images of general dust movement were obtained, nor were any dust devils "caught on camera" owing to their ephemeral and unpredictable appearance, and the fact that there was deceptively little residue of their actions. If, however, a camera were to take a 360 degree continuous recording over a period of a year, and the film were then to be shown at high speed over a period a several minutes, the impression might be that of a region ravaged by air vorticity and dust movement. Extrapolate this over geological time, and it is possible to visualize dust devils as prime aeolian agents, rather than insignificant vagaries of nature, On Mars, the thin atmosphere permits the surface of the planet to be heated but it does not itself retain heat with the capacity of the earth's atmosphere. This gives rise to greater thermal instability near the surface of Mars as "warm" air pockets diapiritically inject themselves into higher atmospheric layers. Resulting boundary-layer vorticity on Mars might therefore be expected to produce dust devils in abundance, if only seasonally. The spectacular images of dust devils obtained by Pathfinder within its brief functional period on the planet testify to the probability of highly frequent surface vorticity in light of the above reasoning about observational probability. Notably, the Pathfinder devils appeared to be at least a kilometer in height. There are several consequences for the geology of Mars, and for human exploration, if

  5. Dust emission: small-scale processes with global consequences

    USGS Publications Warehouse

    Okin, Gregory S.; Bullard, Joanna E.; Reynolds, Richard L.; Ballantine, John-Andrew C.; Schepanski, Kerstin; Todd, Martin C.; Belnap, Jayne; Baddock, Matthew C.; Gill, Thomas E.; Miller, Mark E.

    2011-01-01

    Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored.

  6. Experimental research on dust lifting by propagating shock wave

    NASA Astrophysics Data System (ADS)

    Żydak, P.; Oleszczak, P.; Klemens, R.

    2016-05-01

    The aim of the presented work was to study the dust lifting process from a layer of dust behind a propagating shock wave. The experiments were conducted with the use of a shock tube and a specially constructed, five-channel laser optical device enabling measurements at five positions located in one vertical plane along the height of the tube. The system enabled measurements of the delay in lifting up of the dust from the layer, and the vertical velocity of the dust cloud was calculated from the dust concentration measurements. The research was carried out for various initial conditions and for three fractions of black coal dust. In the presented tests, three shock wave velocities: 450, 490 and 518 m/s and three dust layer thicknesses, equal to 1.0, 1.5 and 2.0 mm, were taken into consideration. On the grounds of the obtained experimental results, it was assumed that the vertical component of the lifted dust velocity is a function of the dust particle diameter, the velocity of the air flow in the channel, the layer thickness and the dust bulk density. It appeared, however, that lifting up of the dust from the thick layers, thicker than 1 mm, is a more complex process than that from thin layers and still requires further research. A possible explanation is that the shock wave action upon the thick layer results in its aggregation in the first stage of the dispersing process, which suppresses the dust lifting process.

  7. Dust: Small-scale processes with global consequences

    NASA Astrophysics Data System (ADS)

    Okin, Gregory S.; Bullard, Joanna E.; Reynolds, Richard L.; Ballantine, John-Andrew C.; Schepanski, Kerstin; Todd, Martin C.; Belnap, Jayne; Baddock, Matthew C.; Gill, Thomas E.; Miller, Mark E.

    2011-07-01

    Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored.

  8. Dust: Small-scale processes with global consequences

    USGS Publications Warehouse

    Okin, G.S.; Bullard, J.E.; Reynolds, R.L.; Ballantine, J.-A.C.; Schepanski, K.; Todd, M.C.; Belnap, J.; Baddock, M.C.; Gill, T.E.; Miller, M.E.

    2011-01-01

    Desert dust, both modern and ancient, is a critical component of the Earth system. Atmospheric dust has important effects on climate by changing the atmospheric radiation budget, while deposited dust influences biogeochemical cycles in the oceans and on land. Dust deposited on snow and ice decreases its albedo, allowing more light to be trapped at the surface, thus increasing the rate of melt and influencing energy budgets and river discharge. In the human realm, dust contributes to the transport of allergens and pathogens and when inhaled can cause or aggravate respiratory diseases. Dust storms also represent a significant hazard to road and air travel. Because it affects so many Earth processes, dust is studied from a variety of perspectives and at multiple scales, with various disciplines examining emissions for different purposes using disparate strategies. Thus, the range of objectives in studying dust, as well as experimental approaches and results, has not yet been systematically integrated. Key research questions surrounding the production and sources of dust could benefit from improved collaboration among different research communities. These questions involve the origins of dust, factors that influence dust production and emission, and methods through which dust can be monitored. ?? Author(s) 2011.

  9. Several Dust Devils in Gusev Crater, Sol 461

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a several dust devils -- whirlwinds that loft dust into the air -- moving across a plain below the hillside vantage point of NASA's Mars Exploration Rover Spirit. Several of the dust devils are visible at once in some of the 21 frames in this sequence. The local solar time was about 2 p.m., when the ground temperature was high enough to cause turbulence that kicks up dust devils as the wind blows across the plain. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames. Spirit's navigation camera took these images on the rover's 461st martian day, or sol (April 20, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  10. Deflagration to detonation transition fueled by dust layers

    NASA Astrophysics Data System (ADS)

    Li, Y.-C.; Harbaugh, A. S.; Alexander, C. G.; Kauffman, C. W.; Sichel, M.

    1995-12-01

    The roles which dust layers play in severe dust explosions were investigated in a 70 m long and 30 cm inside diameter horizontal Flame Acceleration Tube (FAT) with one end closed and the other end open to the atmosphere. A variety of dusts such as corn dust, cornstarch, Mira Gel starch, wheat dust, and wood flour were layered on the bottom half of the FAT. To initiate the combustion process, a detonation tube filled with a stoichiometric H2/O2 mixture at room temperature and 1 atm pressure was used to ignite a short presuspended dust cloud with a dust concentration of 500 600 g/m3. Combustion waves generated by this dust cloud travel toward the open end of the FAT and are continuously fueled by the dust/air mixtures. Flame propagation processes in the FAT were closely monitored by a variety of measuring instruments at different locations. The study demonstrates that stable quasi-detonation were reached in some runs, but self-sustained Chapman-Jouguet detonations were not observed possibly due to the limitation of the tube length. Attempts were made to determine the structure of dust detonations fueled by a dust layer. Preliminary evidence indicates that for Mira Gel starch the leading shock is essentially a triple shock configuration which involves a Mach stem and for wheat and wood dusts there possibly exists a multi-headed spin structure.

  11. Orbital Observations of Dust Lofted by Daytime Convective Turbulence

    NASA Astrophysics Data System (ADS)

    Fenton, Lori; Reiss, Dennis; Lemmon, Mark; Marticorena, Béatrice; Lewis, Stephen; Cantor, Bruce

    2016-03-01

    Over the past several decades, orbital observations of lofted dust have revealed the importance of mineral aerosols as a climate forcing mechanism on both Earth and Mars. Increasingly detailed and diverse data sets have provided an ever-improving understanding of dust sources, transport pathways, and sinks on both planets, but the role of dust in modulating atmospheric processes is complex and not always well understood. We present a review of orbital observations of entrained dust on Earth and Mars, particularly that produced by the dust-laden structures produced by daytime convective turbulence called "dust devils". On Earth, dust devils are thought to contribute only a small fraction of the atmospheric dust budget; accordingly, there are not yet any published accounts of their occurrence from orbit. In contrast, dust devils on Mars are thought to account for several tens of percent of the planet's atmospheric dust budget; the literature regarding martian dust devils is quite rich. Because terrestrial dust devils may temporarily contribute significantly to local dust loading and lowered air quality, we suggest that martian dust devil studies may inform future studies of convectively-lofted dust on Earth. As on Earth, martian dust devils form most commonly when the insolation reaches its daily and seasonal peak and where a source of loose dust is plentiful. However this pattern is modulated by variations in weather, albedo, or topography, which produce turbulence that can either enhance or suppress dust devil formation. For reasons not well understood, when measured from orbit, martian dust devil characteristics (dimensions, and translational and rotational speeds) are often much larger than those measured from the ground on both Earth and Mars. Studies connecting orbital observations to those from the surface are needed to bridge this gap in understanding. Martian dust devils have been used to remotely probe conditions in the PBL (e.g., CBL depth, wind velocity

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

    USGS Publications Warehouse

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

    2014-01-01

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

  13. 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.

  14. Falling film evaporator

    DOEpatents

    Bruns, Lester E.

    1976-01-01

    A falling film evaporator including a vertically oriented pipe heated exteriorly by a steam jacket and interiorly by a finned steam tube, all heating surfaces of the pipe and steam tube being formed of a material wet by water such as stainless steel, and packing within the pipe consisting of Raschig rings formed of a material that is not wet by water such as polyvinylidene fluoride.

  15. Observational study of formation mechanism, vertical structure, and dust emission of dust devils over the Taklimakan Desert, China

    NASA Astrophysics Data System (ADS)

    Liu, Chong; Zhao, Tianliang; Yang, Xinghua; Liu, Feng; Han, Yongxiang; Luan, Zhaopeng; He, Qing; Rood, Mark; Yuen, Wangki

    2016-04-01

    A field observation of dust devils was conducted at Xiaotang over the Taklimakan Desert (TD), China, from 7 to 14 July 2014. The measurements of dust devil opacity with the digital optical method and the observed atmospheric boundary layer conditions were applied to investigate the dust devils' formation mechanism, vertical structure, and dust emissions. The critical conditions in the atmospheric boundary layer for dust devil formation were revealed with the land-air surface temperature difference of higher than 15°C, the enhanced momentum flux and sensible heat flux up to 0.54 kg m-1 s-2 and 327 W m-2, respectively, the weak vertical wind shear with the low wind shear index α < 0.10, and the unstable stratification in the lower atmosphere. Based on observed dust opacities, it is identified that a typical dust devil was vertically structured with central updrafts and peripheral downdrafts of dust particles with the asymmetrically horizontal distribution of dust in a rotating dust column. The vertical flux of near-surface dust emissions was also estimated in a range from 5.4 × 10-5 to 9.6 × 10-5 kg m-2 s-1 for a typical dust devil event over TD.

  16. Lead in Chinese villager house dust

    NASA Astrophysics Data System (ADS)

    Bi, Xiangyang; Liu, Jinling; Han, Zhixuan

    2016-04-01

    House dust has been recognized as an important contributor to children's blood Pb. Here we conducted a comprehensive study to investigate geographical variation of Pb in Chinese villager house dust. The concentrations of Pb in 477 house dust samples collected from twenty eight areas throughout China varied from 12 to 2510 mg/kg, with geometric mean and median concentration of 54 mg/kg and 42 mg/kg, respectively. The median Pb concentrations in different geographical areas ranged from 16 (Zhangjiakou, Hebei) to 195 mg/kg (Loudi, Hunan). The influences of outdoor soil Pb concentrations, dates of construction, house decorative materials, heating types, and site specific pollution on Pb concentrations in house dust were evaluated. No correlations were found between the house dust Pb concentrations and the age of houses, as well as house decorative materials. Whereas outdoor soil, coal combustion, and site specific pollution may be potential Pb sources. The results of scanning electron microscopy (SEM) showed that Pb bearing particles appeared as cylindrical, flaky and irregular aggregates with the particle size ranging from about 10 to 800 μm. The energy dispersive X-ray microanalysis (EDX) suggested that Pb in the dust particles may be associated with calcium compounds. But the major fraction of Pb in the household dust samples was found to be strongly bound to Fe-Mn oxide phases (37%) while Pb present in minor fractions individually making up between 14 and 18% was characterized in falling order as residual, carbonate, organic/sulphide and exchangeable fractions by the sequential extraction method applied. Bioaccessible Pb making up an average proportion of 53% in the household dusts was significantly correlated to the Fe-Mn oxide phases of Pb.

  17. Direct observations of the atmospheric processing of Asian mineral dust

    NASA Astrophysics Data System (ADS)

    Sullivan, R. C.; Guazzotti, S. A.; Sodeman, D. A.; Prather, K. A.

    2007-02-01

    The accumulation of secondary acids and ammonium on individual mineral dust particles during ACE-Asia has been measured with an online single-particle mass spectrometer, the ATOFMS. Changes in the amounts of sulphate, nitrate, and chloride mixed with dust particles correlate with air masses from different source regions. The uptake of secondary acids depended on the individual dust particle mineralogy; high amounts of nitrate accumulated on calcium-rich dust while high amounts of sulphate accumulated on aluminosilicate-rich dust. Oxidation of S(IV) to S(VI) by iron in the aluminosilicate dust is a possible explanation for this enrichment of sulphate, which has important consequences for the fertilization of remote oceans by soluble iron. This study shows the segregation of sulphate from nitrate and chloride in individual aged dust particles for the first time. A transport and aging timeline provides an explanation for the observed segregation. Our data suggests that sulphate became mixed with the dust first. This implies that the transport pathway is more important than the reaction kinetics in determining which species accumulate on mineral dust. Early in the study, dust particles in volcanically influenced air masses were mixed predominately with sulphate. Dust mixed with chloride then dominated over sulphate and nitrate when a major dust front reached the R. V. Ronald Brown. We hypothesize that the rapid increase in chloride on dust was due to mixing with HCl(g) released from acidified sea salt particles induced by heterogeneous reaction with volcanic SO2(g), prior to the arrival of the dust front. The amount of ammonium mixed with dust correlated strongly with the total amount of secondary acid reaction products in the dust. Submicron dust and ammonium sulphate were internally mixed, contrary to frequent reports that they exist as external mixtures. The size distribution of the mixing state of dust with these secondary species validates previous mechanisms of

  18. Soil physical and chemical parameter effects on dust generation potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fugitive dust is the most visible evidence of wind erosion. Fugitive dust obscures visibility, pollutes the air, fouls machinery, imperils animal and human health, and carries a disproportionate amount of plant nutrients and trace elements. As part of a laboratory pilot study in preparation for fi...

  19. House-Dust Allergy

    PubMed Central

    Johnson, C. A.

    1982-01-01

    House-dust allergy is a common cause of perennial allergic rhinitis and extrinsic asthma. Symptoms tend to be worse when the patient is in bed. A positive skin test properly performed and interpreted confirms the diagnosis. The house-dust mite is the most important antigenic component of house-dust. Treatment consists of environmental control directed at reducing the mite content of bedroom dust, plus control of symptoms with drugs. Immunotherapy is controversial. ImagesFig. 1 PMID:21286201

  20. China Dust and Sand

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Dust and Sand Sweep Over Northeast China     View Larger Image ... these views of the dust and sand that swept over northeast China on March 10, 2004. Information on the height of the dust and an ...

  1. Middle East Dust

    Atmospheric Science Data Center

    2013-04-16

    ... only some of the dust over eastern Syria and southeastern Turkey can be discerned. The dust is much more obvious in the center panel, ... 18, 2002 - A large dust plume extends across Syria and Turkey. project:  MISR category:  gallery ...

  2. Dust in the Universe

    ERIC Educational Resources Information Center

    Hemenway, Mary Kay; Armosky, Brad J.

    2004-01-01

    Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even dust is getting its due, but not the dust everyone is familiar with. People seldom consider the dust in…

  3. Niamey Dust Observations

    DOE Data Explorer

    Flynn, Connor

    2008-10-01

    Niamey aerosol are composed of two main components: dust due to the proximity of the Sahara Desert, and soot from local and regional biomass burning. The purpose of this data product is to identify when the local conditions are dominated by the dust component so that the properties of the dust events can be further studied.

  4. Infrared emission from interplanetary dust

    NASA Astrophysics Data System (ADS)

    Temi, P.; de Bernardis, P.; Masi, S.; Moreno, G.; Salama, A.

    1989-02-01

    Standard models of the interplanetary dust emission fail to account satisfactorily for IR observations. A new model of the dust, based on very simple assumptions on the grain structure (spherical and homogeneous) and chemical composition (astronomical silicates, graphite, blackbodies) is developed. Updated values of the refractive indexes have been included in the analysis. The predictions of the model (absolute values of the fluxes, spectral shape, elongation dependence of the emission) have then been compared with all the available IR observations performed by the ARGO (balloon-borne experiment by University of Rome), AFGL and Zodiacal Infrared Project (ZIP) (rocket experiments by Air Force Geophysics Laboratory, Bedford, Mass.), and IRAS satellite. Good agreement is found when homogeneous data sets from single experiments (e.g., ZIP and ARGO) are considered separately.

  5. Advances in Dust Detection and Removal for Tokamaks

    NASA Astrophysics Data System (ADS)

    Campos, A.; Skinner, C. H.; Roquemore, A. L.; Leisure, J. O. V.; Wagner, S.

    2008-11-01

    Dust diagnostics and removal techniques are vital for the safe operation of next step fusion devices such as ITER. An electrostatic dust detector[1] developed in the laboratory is being applied to NSTX. In the tokamak environment, large particles or fibres can fall on the grid potentially causing a permanent short. We report on the development of a gas puff system that uses helium to clear such particles from the detector. Experiments with varying nozzle designs, backing pressures, puff durations, and exit flow orientations have obtained an optimal configuration that effectively removes particles from a 25 cm^2 area. Dust removal from next step tokamaks will be required to meet regulatory dust limits. A tripolar grid of fine interdigitated traces has been designed that generates an electrostatic travelling wave for conveying dust particles to a ``drain.'' First trials have shown particle motion in optical microscope images. [1] C. H. Skinner et al., J. Nucl. Mater., 376 (2008) 29.

  6. `In free fall'

    NASA Astrophysics Data System (ADS)

    Beijerinck, Herman C. W.

    2014-01-01

    Physicists in the lead of a fiction book or a play, that's a rare event! Writers in general do not understand physics, while physicists seldom have the talent of writing for a large audience. So when it happens, we should rejoice. The up-and-coming German author Juli Zeh [1] (1974), who studied law, has succeeded in combining beautiful prose, psychological drama, crime and physics in a challenging book `In free fall' [2]. A good friend of hers, Bettina Bruinier, has put the core message of the book into a compelling play in the `Volkstheater' in Munich [1]. Yes, it can be done.

  7. [Quality of interior air: biological contaminants and their effects on health; bioaerosols and gathering techniques].

    PubMed

    Bălan, Gabriela

    2007-01-01

    Indoor Air Quality: biological contaminants and health effects; airborne organisms and sampling instruments. Biological contaminants include bacteria, molds, viruses, animal dander and cat saliva, house dust, mites, cockroaches and pollen. Symptoms of health problems caused by biological pollutants include sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fevers. Children, elderly people with breathing problems, allergies and lung diseases are particularly susceptible to disease-causing biological agents in the indoor air. It is convenient to consider microbiological samplers for collecting organisms in air as falling into several broad categories. Many popular microbiological air samplers use the principle of impaction to trap the organisms by impacting them directly on to agar. Further distinct groups are the impingers, which operate by impinging organisms into liquid. PMID:18441954

  8. Interstellar Dust Instrumentation

    NASA Astrophysics Data System (ADS)

    Sternovsky, Zoltan; Gruen, E.; Horanyi, M.; Drake, K.; Collette, A.; Kempf, S.; Srama, R.; Postberg, F.; Krueger, H.; Auer, S.

    2010-10-01

    Interstellar grains traversing the inner planetary system have been identified by the Ulysses dust detector. Space dust detectors on other missions confirmed this finding. Analysis of the Stardust collectors is under way to search for and analyze such exotic grains. Interstellar dust particles can be detected and analyzed in the near-Earth space environment. New instrumentation has been developed to determine the origin of dust particles and their elemental composition. A Dust Telescope is a combination of a Dust Trajectory Sensor (DTS, Rev. Sci. Instrum. 79, 084501, 2008) together with a high mass resolution mass analyzer for the chemical composition of dust particles in space. Dust particles' trajectories are determined by the measurement of induced electric signals when a charged grain flies through a position sensitive electrode system. A modern DTS can measure dust particles as small as 0.2 micron in radius and dust speeds up to 100 km/s. Large area chemical analyzers of 0.1 m2 sensitive area have been tested at a dust accelerator and it was demonstrated that they have sufficient mass resolution to resolve ions with atomic mass number up to >100 (Earth, Moon and Planets, DOI: 10.1007/s11038-005-9040-z, 2005; Rev. Sci. Instrum. 78, 014501, 2007). The advanced Dust Telescope is capable of identifying interstellar and interplanetary grains, and measuring their mass, velocity vector, charge, elemental and isotopic compositions. An Active Dust Collector combines a DTS with an aerogel or other dust collector materials, e.g. like the ones used on the Stardust mission. The combination of a DTS with a dust collector provides not only individual trajectories of the collected particles but also their impact time and position on the collector which proves essential in finding collected sub-micron sized grains on the collector.

  9. Gusev Dust Devil Movie, Sol 456 (Plain and Isolated)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 456th martian day, or sol (April 15, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera. Each frame in this movie has the raw image on the top half and a processed version in the lower half that enhances contrast and removes stationary objects, producing an image that is uniformly gray except for features that change from frame to frame.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection should trigger dust devils.

    Scientists will use the images to study several things. Tracking the dust devils tells which way the wind blows at different times

  10. Gusev Dust Devil Movie, Sol 459 (Plain and Isolated)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a dust devil scooting across a plain inside Gusev Crater on Mars as seen from the NASA rover Spirit's hillside vantage point during the rover's 459th martian day, or sol (April 18, 2005). The individual images were taken about 20 seconds apart by Spirit's navigation camera. Each frame in this movie has the raw image on the top half and a processed version in the lower half that enhances contrast and removes stationary objects, producing an image that is uniformly gray except for features that change from frame to frame.

    The movie results from a new way of watching for dust devils, which are whirlwinds that hoist dust from the surface into the air. Spirit began seeing dust devils in isolated images in March 2005. At first, the rover team relied on luck. It might catch a dust devil in an image or it might miss by a few minutes. Using the new detection strategy, the rover takes a series of 21 images. Spirit sends a few of them to Earth, as well as little thumbnail images of all of them. Team members use the 3 big images and all the small images to decide whether the additional big images have dust devils. For this movie, they specifically told Spirit to send back frames that they knew had dust devils.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection should trigger dust devils.

    Scientists will use the images to study several things. Tracking the dust devils tells which way the wind blows at different times

  11. Dust and Planetary Rings

    NASA Astrophysics Data System (ADS)

    Siddiqui, Muddassir

    ABSTRACT Space is not empty it has comic radiations (CMBR), dust etc. Cosmic dust is that type of dust which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of dust is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains dust grains and when these dust grains starts compacting then it turns to dense clouds, planetary ring dust and circumstellar dust. Dust grains are mainly silicate particles. Dust plays a major role in our solar system, for example in zodiacal light, Saturn's B ring spokes, planetary rings at Jovian planets and comets. Observations and measurements of cosmic dust in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider dust in its most recycled state. Cosmic dust have radiative properties by which they can be detected. Cosmic dusts are classified as intergalactic dusts, interstellar dusts and planetary rings. A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have rings. But the most notable one is the Saturn's ring which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous ring system. The ring swirling around Saturn consists of chunks of ice and dust. Most rings were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's rings might be older than that. The dust particles in the ring collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the rings. Pluto is not known to have any ring system but some Astronomers believe that New Horizons probe might find a ring system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary ring

  12. Saxon Falls Dam rehabilitation

    SciTech Connect

    Rudolph, R.M.; Quist, J.E.

    1995-12-31

    The Saxon Falls Hydro Project is a high-head hydro owned and operated by Northern States Power Company (NSP) in northwest Wisconsin. Saxon Falls comprises a concrete buttress overflow spillway; mass-concrete tainter gate spillway, conduit intake, and nonoverflow section; earth dam; 1,600-foot-long, 72-inch-diameter steel conduit; two 150-foot-long, 54-inch-diameter penstocks; steel surge tank; and reinforced concrete powerhouse. All structures are founded on bedrock. Engineering inspections revealed severe concrete deterioration and leakage within the intake and deterioration of the middle nonoverflow section. Subsequent to the inspection, concrete cores confirmed the level of deterioration and indicated that immediate measures were necessary to correct the deficiencies and restore project integrity. Because the dam is located on the border between Michigan and Wisconsin, coordination with the respective Departments of Natural Resources was crucial to obtain permits to construct the repairs. Due to concerns regarding a sensitive fishery, a reservoir drawdown was not allowed. To accomplish the work and allow for a suitable construction area, a special braced sheetpile cofferdam was required to complete the project. NSP elected to complete the construction using its own special-construction crews. Close coordination allowed construction personnel, the owner, and the engineer to overcome difficulties encountered during construction.

  13. [Can falls be prevented?].

    PubMed

    Dubousset, Jean

    2014-06-01

    Most recommendations and measures intended to prevent falls focus on the elderly (see HAS guideline of April 2009) but, in our opinion, this isfar too late: prevention must begin much earlier, not only by identifying persons at risk, but also by providing personalized lifestyle advice adapted to each individual's biomechanical, somatic, neurological and biological characteristics. The first preventive measure is to identify a possible deterioration of balance, starting with a physical examination at the age of 45 and repeated regularly throughout life. Extrinsic preventive measures focusing on the domestic and external environments are clearly necessary. But what is most important is to detect and, if necessary, correct any degradation of intrinsic (intracorporeal or somatic) factors starting at the age of 45 years; these include vision, vestibular function and balance, proprioception, and psychological and neurological status. Chronic illnesses and their treatments must also be taken into account: treatment must be limited to indispensable drugs; sedative psychotropics must be avoided if possible; and polymedication must be tightly controlled, as it is a major risk factor for falls. Prevention also requires a diet sufficiently rich in protein, calcium and vitamin D3 (to prevent osteoporosis), and regular daily exercise adapted to the individual, if possible associated with a simultaneous cognitive task. The last key point is the absolute need for thorough functional rehabilitation after any accidental or medical trauma, regardless of age, with the aim of restoring functional status to that existing prior to the accident. PMID:26983186

  14. Asian dust events of April 1998

    NASA Astrophysics Data System (ADS)

    Husar, R. B.; Tratt, D. M.; Schichtel, B. A.; Falke, S. R.; Li, F.; Jaffe, D.; Gassó, S.; Gill, T.; Laulainen, N. S.; Lu, F.; Reheis, M. C.; Chun, Y.; Westphal, D.; Holben, B. N.; Gueymard, C.; McKendry, I.; Kuring, N.; Feldman, G. C.; McClain, C.; Frouin, R. J.; Merrill, J.; Dubois, D.; Vignola, F.; Murayama, T.; Nickovic, S.; Wilson, W. E.; Sassen, K.; Sugimoto, N.; Malm, W. C.

    2001-08-01

    On April 15 and 19, 1998, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest. The windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring, and through serendipitous observations. The April 15 dust cloud was recirculating, and it was removed by a precipitating weather system over east Asia. The April 19 dust cloud crossed the Pacific Ocean in 5 days, subsided to the surface along the mountain ranges between British Columbia and California, and impacted severely the optical and the concentration environments of the region. In east Asia the dust clouds increased the albedo over the cloudless ocean and land by up to 10-20%, but it reduced the near-UV cloud reflectance, causing a yellow coloration of all surfaces. The yellow colored backscattering by the dust eludes a plausible explanation using simple Mie theory with constant refractive index. Over the West Coast the dust layer has increased the spectrally uniform optical depth to about 0.4, reduced the direct solar radiation by 30-40%, doubled the diffuse radiation, and caused a whitish discoloration of the blue sky. On April 29 the average excess surface-level dust aerosol concentration over the valleys of the West Coast was about 20-50 μg/m3 with local peaks >100 μg/m3. The dust mass mean diameter was 2-3 μm, and the dust chemical fingerprints were evident throughout the West Coast and extended to Minnesota. The April 1998 dust event has impacted the surface aerosol concentration 2-4 times more than any other dust event since 1988. The dust events were observed and interpreted by an ad hoc international web-based virtual community. It would be useful to set up a community-supported web-based infrastructure to monitor the global aerosol pattern for such extreme aerosol events, to alert and to inform the interested communities, and to facilitate collaborative

  15. Asian dust events of April 1998

    USGS Publications Warehouse

    Husar, R.B.; Tratt, D.M.; Schichtel, B.A.; Falke, S.R.; Li, F.; Jaffe, D.; Gasso, S.; Gill, T.; Laulainen, N.S.; Lu, F.; Reheis, M.C.; Chun, Y.; Westphal, D.; Holben, B.N.; Gueymard, C.; McKendry, I.; Kuring, N.; Feldman, G.C.; McClain, C.; Frouin, R.J.; Merrill, J.; DuBois, D.; Vignola, F.; Murayama, T.; Nickovic, S.; Wilson, W.E.; Sassen, K.; Sugimoto, N.; Malm, W.C.

    2001-01-01

    On April 15 and 19, 1998, two intense dust storms were generated over the Gobi desert by springtime low-pressure systems descending from the northwest. The windblown dust was detected and its evolution followed by its yellow color on SeaWiFS satellite images, routine surface-based monitoring, and through serendipitous observations. The April 15 dust cloud was recirculating, and it was removed by a precipitating weather system over east Asia. The April 19 dust cloud crossed the Pacific Ocean in 5 days, subsided to the surface along the mountain ranges between British Columbia and California, and impacted severely the optical and the concentration environments of the region. In east Asia the dust clouds increased the albedo over the cloudless ocean and land by up to 10-20%, but it reduced the near-UV cloud reflectance, causing a yellow coloration of all surfaces. The yellow colored backscattering by the dust eludes a plausible explanation using simple Mie theory with constant refractive index. Over the West Coast the dust layer has increased the spectrally uniform optical depth to about 0.4, reduced the direct solar radiation by 30-40%, doubled the diffuse radiation, and caused a whitish discoloration of the blue sky. On April 29 the average excess surface-level dust aerosol concentration over the valleys of the West Coast was about 20-50 ??g/m3 with local peaks >100 ??g/m3. The dust mass mean diameter was 2-3 ??m, and the dust chemical fingerprints were evident throughout the West Coast and extended to Minnesota. The April 1998 dust event has impacted the surface aerosol concentration 2-4 times more than any other dust event since 1988. The dust events were observed and interpreted by an ad hoc international web-based virtual community. It would be useful to set up a community-supported web-based infrastructure to monitor the global aerosol pattern for such extreme aerosol events, to alert and to inform the interested communities, and to facilitate collaborative

  16. 42 CFR 84.1147 - Silica mist test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Silica mist test for dust, fume, and mist... Efficiency Respirators and Combination Gas Masks § 84.1147 Silica mist test for dust, fume, and mist... nor more than 25 milligrams of silica mist, weighed as silica dust, per cubic meter of air. (d)...

  17. 42 CFR 84.1147 - Silica mist test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Silica mist test for dust, fume, and mist... Efficiency Respirators and Combination Gas Masks § 84.1147 Silica mist test for dust, fume, and mist... nor more than 25 milligrams of silica mist, weighed as silica dust, per cubic meter of air. (d)...

  18. 42 CFR 84.1147 - Silica mist test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Silica mist test for dust, fume, and mist... Efficiency Respirators and Combination Gas Masks § 84.1147 Silica mist test for dust, fume, and mist... nor more than 25 milligrams of silica mist, weighed as silica dust, per cubic meter of air. (d)...

  19. 42 CFR 84.1147 - Silica mist test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Silica mist test for dust, fume, and mist... Efficiency Respirators and Combination Gas Masks § 84.1147 Silica mist test for dust, fume, and mist... nor more than 25 milligrams of silica mist, weighed as silica dust, per cubic meter of air. (d)...

  20. 42 CFR 84.1149 - Airflow resistance tests; all dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Airflow resistance tests; all dust, fume, and mist... RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84.1149 Airflow resistance tests; all dust, fume, and...

  1. 42 CFR 84.1140 - Dust, fume, and mist respirators; performance requirements; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Dust, fume, and mist respirators; performance... PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84.1140 Dust, fume, and mist respirators; performance...

  2. 42 CFR 84.1147 - Silica mist test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Silica mist test for dust, fume, and mist... Efficiency Respirators and Combination Gas Masks § 84.1147 Silica mist test for dust, fume, and mist... nor more than 25 milligrams of silica mist, weighed as silica dust, per cubic meter of air. (d)...

  3. Dust adhesion on Viking lander camera window

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1978-01-01

    Studies of dust impingement on a duplicate Viking Lander camera window indicated the possibility of window obscuration after several days of exposure even at low dust concentration levels. As a result the following corrective measures were recommended: (1) The clearance between the housing surface and the camera post should be eliminated by using an appropriately designed plastic skirt: (2) The three horizontal ledges below the window inside the cavity act as bases for pile-up of dust that slides down the window surface; they should be replaced by a single inclined plane down which the dust will slide and fall out on the ground: (3) Adhered dust on the window surface can be removed by high pressure CO2 jets directed down against the window; the amount of CO2 gas needed for the entire mission can be carried in a 3 1/2-inch diameter sphere equipped with a remotely programable valve. These measures were incorporated in the design of the lander camera system. The continued high quality of photographs transmitted from the Viking spacecraft several months after landing attests to their effectiveness.

  4. Simulating Mars' Dust Cycle with a Mars General Circulation Model: Effects of Water Ice Cloud Formation on Dust Lifting Strength and Seasonality

    NASA Technical Reports Server (NTRS)

    Kahre, Melinda A.; Haberle, Robert; Hollingsworth, Jeffery L.

    2012-01-01

    The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere [1,2,3]. Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer [4]. Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across [5]. Regional storm activity is enhanced before northern winter solstice (Ls200 degrees - 240 degrees), and after northern solstice (Ls305 degrees - 340 degrees ), which produces elevated atmospheric dust loadings during these periods [5,6,7]. These pre- and post- solstice increases in dust loading are thought to be associated with transient eddy activity in the northern hemisphere with cross-equatorial transport of dust leading to enhanced dust lifting in the southern hemisphere [6]. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles [8,9,10]. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading.

  5. Interstellar Dust - A Review

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2012-01-01

    The study of the formation and the destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic materials. Although dust with all its components plays an important role in the evolution of interstellar physics and chemistry and in the formation of organic materials, little is known on the formation and destruction processes of carbonaceous dust. Laboratory experiments that are performed under conditions that simulate interstellar and circumstellar environments to provide information on the nature, the size and the structure of interstellar dust particles, the growth and the destruction processes of interstellar dust and the resulting budget of extraterrestrial organic molecules. A review of the properties of dust and of the laboratory experiments that are conducted to study the formation processes of dust grains from molecular precursors will be given.

  6. Light Dust Devil Tracks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    14 October 2004 Many Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images exhibit wild patterns of dark streaks thought to have formed by the passage of many dust devils. The dust devils disrupt the dust coating the martian surface, leaving behind a streak. However, not all dust devils make streaks, and not all dust devil streaks are dark. Some are light---it simply depends upon which is darker, the substrate or the dust that the spinning vortex disrupts. The example of light-toned dust devil streaks shown here is located in southern Schiaparelli Basin near 5.3oS, 343.3oW. The image covers an area about 3 km (1.9 mi) across; sunlight illuminates the scene from the left/upper left.

  7. [Falls in patients with dementia].

    PubMed

    Yamaguchi, Kiyoshi

    2008-11-01

    People with cognitive impairment are at about 2 to 3 times higher risk of falling compared with cognitively intact elderly. Incidence of falls among patients with Alzheimer's disease (AD) is high, nevertheless the clinical feature common in patients with mild to moderate AD is the absence of motor impairment. Recent studies suggest that the divided attention markedly impairs the ability of patients with AD to regulate the gait. Falls are particularly common in Dementia with Lewy bodies (DLB) patients and may aid diagnosis, and the falls are associated with parkinsonism and other unclear factors. Treatment studies evaluating fall reduction strategies in dementia patients are a priority. PMID:18974447

  8. Sidebar: DUSTRAN Predicts Dust Dispersion from Military Training Exercises

    SciTech Connect

    Rutz, Frederick C.; Allwine, K Jerry

    2006-01-01

    In 2001, the U.S. Department of Energy’s Pacific Northwest Laboratory in Richland, Washington, began a four-year project to create an atmospheric dispersion modeling system known as DUSTRAN, (an acronym for dust transport), for the Department of Defense. DUSTRAN purpose is assessing the impact of military training and testing on local and regional air quality managing dust-generating activities and developing dust-mitigation strategies. The primary users of the DUSTRAN system are officials of military bases where windblown dust is a concern.

  9. Mineral dust transport toward Hurricane Helene (2006)

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  10. Retrospective analysis of fatal falls.

    PubMed

    Thierauf, Annette; Preuss, Johanna; Lignitz, Eberhard; Madea, Burkhard

    2010-05-20

    Fatal falls are frequent and inhomogeneous events and affect every age. The criminalistic classification can often only be done on the basis of extensive investigations and the autopsy results. We retrospectively surveyed 291 cases of fatal falls on which a post-mortem examination had been carried out in the institutes of Forensic Medicine in Bonn and Greifswald. In large part, these cases are falls from height (n=123) and ground-level falls (n=122). These are compared to fatal falls down a stairs (n=46); the analysis is confined to injuries to the cranium. In ground-level falls the injury pattern in falls under the influence of alcohol differs from that of falls with no alcohol in the case history: all injuries are seen in higher relative frequency in casualties after the consumption of alcohol. In falls from height, the previous consumption of alcohol did not influence the injury pattern; the intracranial traumas are seen in decreasing frequency with increasing heights. The aim of this retrospective analysis is to present injury patterns and influencing factors like fall heights and alcohol for the different kinds of falls on the basis of our collective and to demonstrate similarities and differences between the subgroups. PMID:20176452

  11. How to catch a falling fruit

    NASA Astrophysics Data System (ADS)

    Marantan, Andrew; Mahadevan, Lakshminarayanan

    2015-03-01

    A variety of fish engage in complex hunting behaviors involving catching airborne prey falling to the surface of the water. In principle this requires that the fish develop internal models describing both the falling prey and its own motion relative to that prey. However learning such models is complicated by the fact that the fish must also account for noise in optical measurements and the refraction occurring at the air/water interface. Inspired by experimental observations, we describe how one such species (Brycon guatemalensis) might feasibly overcome these obstacles and learn a model accurate enough to catch falling fruit. Instead of learning a model for how the fruit falls and a model for how it moves in the water and a model accounting for refraction, we argue that the fish could instead learn one approximate linear model relating a set of measured inputs to a set of measured outputs valid in a limited domain of initial conditions. The fish could then make its control decisions based on the outcome predicted by this combined linear model. We also discuss how the fish can leverage neural transformations of raw data to learn a model with a larger domain of validity and yet more sensitive to noise due to nontrivial Jacobians arising from the neural transformations.

  12. An aerosol generator for the resuspension of cotton dust.

    PubMed

    Weyel, D A; Ellakkani, M; Alarie, Y; Karol, M

    1984-12-01

    An aerosol generator, the Pitt 3 model, was designed, fabricated, and characterized for the resuspension of inhalable particles from bulk cotton dust. The generator was constructed around a loudspeaker whose energy is transferred into an air column through latex rubber dams. This action tumbles the bulk dust, and small particles are loosened which can then be carried out of the column with the air passing through it. Thirty to forty grams of bulk cotton dust produced a stable aerosol concentration for at least 90 min. The maximum output of about 100 mg/m3 can be reduced to lower concentrations by adding dilution air. In one application, the generator produced a stable aerosol cloud in the range of 2 to 30 mg/m3 with a mass median aerodynamic diameter (MMAD) of about 3 microns and a geometric standard deviation (sigma g) of about 1.5. In another application the concentration in an animal exposure chamber was kept at 20.8 mg/m3 with an MMAD = 2.5 microns and a sigma g = 1.8 for over 6 months. The Pitt 3 generator proved to be trouble-free and produced large amounts of inhalable particles from bulk cotton dust. The generator was also used to generate dust clouds from silica powder, fly ash, and cellulose dust. The only requirement for successful resuspension of any dust with this generator is the presence of small particles in the bulk feed dust. PMID:6506079

  13. Energy Matters - Fall 2002

    SciTech Connect

    2002-09-01

    Quarterly newsletter from DOE's Industrial Technologies Program to promote the use of energy-efficient industrial systems. This issue focus of this edition of the Energy Matters Newsletter is on energy and environmental issues. Read more about compressed air's role in productivity, making good motor decisions, and more.

  14. Haul road dust control

    SciTech Connect

    Reed, W.R.; Organiscak, J.A.

    2007-10-15

    A field study was conducted to measure dust from haul trucks at a limestone quarry and a coal preparation plant waste hauling operation. The study found that primarily wind, distance and road treatment conditions notably affected the dust concentrations at locations next to, 50 ft from, and 100 ft away from the unpaved haulage road. Airborne dust measured along the unpaved haul road showed that high concentrations of fugitive dust can be generated with these concentrations rapidly decreasing to nearly background levels within 100 ft of the road. Instantaneous respirable dust measurements illustrated that the trucks generate a real-time dust cloud that has a peak concentration with a time-related decay rate as the dust moves past the sampling locations. The respirable dust concentrations and peak levels were notably diminished as the dust cloud was transported, diluted, and diffused by the wind over the 100 ft distance from the road. Individual truck concentrations and peak levels measured next to the dry road surface test section were quite variable and dependent on wind conditions, particularly wind direction, with respect to reaching the sampling location. The vast majority of the fugitive airborne dust generated from unpaved and untreated haulage roads was non-respirable. 6 figs.

  15. Laboratory study of PCB transport from primary sources to settled dust.

    PubMed

    Liu, Xiaoyu; Guo, Zhishi; Krebs, Kenneth A; Greenwell, Dale J; Roache, Nancy F; Stinson, Rayford A; Nardin, Joshua A; Pope, Robert H

    2016-04-01

    Dust is an important sink for indoor air pollutants, such as polychlorinated biphenyls (PCBs) that were used in building materials and products. In this study, two types of dust, house dust and Arizona Test Dust, were tested in a 30-m(3) stainless steel chamber with two types of panels. The PCB-containing panels were aluminum sheets coated with a PCB-spiked primer or caulk. The PCB-free panels were coated with the same materials but without PCBs. The dust evenly spread on each panel was collected at different times to determine its PCB content. The data from the PCB panels were used to evaluate the PCB migration from the source to the dust through direct contact, and the data from the PCB-free panels were used to evaluate the sorption of PCBs through the dust/air partition. Settled dust can adsorb PCBs from air. The sorption concentration was dependent on the congener concentration in the air and favored less volatile congeners. When the house dust was in direct contact with the PCB-containing panel, PCBs migrated into the dust at a much faster rate than the PCB transfer rate due to the dust/air partition. The dust/source partition was not significantly affected by the congener's volatility. For a given congener, the ratio between its concentration in the dust and in the source was used to estimate the dust/source partition coefficient. The estimated values ranged from 0.04 to 0.16. These values are indicative of the sink strength of the tested house dust being in the middle or lower-middle range. PMID:26849196

  16. Lunar Dust Separation for Toxicology Studies

    NASA Technical Reports Server (NTRS)

    Cooper, Bonnie L.; McKay, D. S.; Riofrio, L. M.; Taylor, L. A.; Gonzalex, C. P.

    2010-01-01

    During the Apollo missions, crewmembers were briefly exposed to dust in the lunar module, brought in after extravehicular activity. When the lunar ascent module returned to micro-gravity, the dust that had settled on the floor now floated into the air, causing eye discomfort and occasional respiratory symptoms. Because our goal is to set an exposure standard for 6 months of episodic exposure to lunar dust for crew on the lunar surface, these brief exposures of a few days are not conclusive. Based on experience with industrial minerals such as sandblasting quartz, an exposure of several months may cause serious damage, while a short exposure may cause none. The detailed characteristics of sub-micrometer lunar dust are only poorly known, and this is the size range of particles that are of greatest concern. We have developed a method for extracting respirable dust (<2.5 micron) from Apollo lunar soils. This method meets stringent requirements that the soil must be kept dry, exposed only to pure nitrogen, and must conserve and recover the maximum amount of both respirable dust and coarser soil. In addition, we have developed a method for grinding coarser lunar soil to produce sufficient respirable soil for animal toxicity testing while preserving the freshly exposed grain surfaces in a pristine state.

  17. Dual measurement terminal fall speeds and multiple Doppler winds

    NASA Technical Reports Server (NTRS)

    Grosh, R. C.

    1983-01-01

    It is shown that radar-derived terminal fall speed measurements can be useful in determining vertical air velocity in the middle troposphere by means of a network of Doppler radars. The theoretical principles of the dual measurement technique are described, and the relationship between measurement accuracies and theoretical estimates of terminal fall speeds is discussed. It is demonstrated that the use of differential reflectivity to estimate terminal fall speeds can reduce the standard error of vertical velocity estimates by 40-50 percent.

  18. Novel approach for suppressing cutting dust using foam on a fully mechanized face with hard parting.

    PubMed

    Wang, Hetang; Wang, Deming; Wang, Qingguo; Jia, Zhiqiang

    2014-01-01

    The cutting dust created by the shearer drum is the main source of dust on a fully mechanized coal face. However, overexposure to respirable dust may cause pneumoconiosis in coal workers, while coal dust may lead to serious explosions. The fully mechanized face known as II1051 Face, found at the Zhuxianzhuang Coal Mine located in east China, generates dust by way of the drum on a high-power shear. The coal seam involves hard rock parting so there is a high concentration of cutting dust when the shearer is working. Thus, we developed a new foam dust suppression method with an air self-suction system based on an analysis of the dust generation characteristics that suppressed the shearer cutting dust level. The new foam system was evaluated in a field test where the dust concentration was measured at two points. The results showed that the foam reduced the cutting dust concentration significantly. The respirable dust exposure levels were reduced from 378.4 mg/m(3)to 53.5 mg/m(3)and the visibility was enhanced dramatically. Thus, we conclude that our new foam system is highly efficient at capturing cutting dust, and it has a much lower water consumption. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: Contact angle of cutting dust sample, migration trajectory of cutting dust, technological process for suppressing shearer cutting dust using foam, the layout of the foam dust suppression system on coal face, real object of the air self-suction type foam generator, the special foam nozzle used for shearers, relevant experimental results of the air self-suction foam system.]. PMID:24521065

  19. Downflow dust filter

    SciTech Connect

    Richard, K.L.

    1986-09-09

    This patent describes an industrial dust filter apparatus comprising: a housing including upper, intermediate and lower sections, the upper section having a top opening inlet for particulate laden gases and the lower section tapering downwardly to a particulate outlet; a plurality of vertically arranged substantially cylindrical filters supported in substantially parallel relationship to each other in the intermediate section of the housing, the filters being closed at their upper ends and having their exterior filter surfaces exposed to particulate laden gases from the inlet; at least one horizontal duct extending across the housing beneath the filters, closed at one end and opening at its other end to a clean gas outlet through a side wall of the intermediate housing section; means communicating the lower open end of the filters through the upper walls of the duct so that the duct functions as a clean gas plenum; a plurality of verturis, vertically supported in the duct, on aligned with each filter; and means in the duct for pulse firing a jet of air upwardly through the venturis into the interior of the filters to remove particulates from the outer surfaces thereof.

  20. 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

  1. Temperature controlled icy dust reservoir of sodium: A possible mechanism for the formation of sporadic sodium layers

    NASA Astrophysics Data System (ADS)

    Qiu, Shican; Tang, Yihuan; Dou, Xiankang

    2015-06-01

    Using seven years, from 2006 to 2013, sodium lidar observations over Hefei, China (31.80°N, 117.3°E), we attempt to propose a possible mechanism for the formation of sporadic sodium layers (SSLs or NaS). We analyze the relationship between low temperature (<150 K) and SSL occurrence and detect a statistically significant link that the low temperature (<150 K) occur in three days before an SSL with an occurrence rate of 93.4% (57/61). The sharp decrease of water vapor concentration nearby before an SSL and the recover after the SSL are also detected frequently. Based upon these evidences and some case studies, we propose an icy dust reservoir in the formation of an SSL. The icy dust could form in the extremely cold mesopause region where the temperature falls below 150 K and it will absorb sodium atoms to form a solid sodium metal film as a sodium reservoir. The icy dust will then sublimate rapidly when meeting with warm air (e.g., 150 K < T < 190 K) and leave behind the solid metal atom film. The remanent sodium film might release vapor sodium atoms finally by some means through high temperature (e.g., >190 K and sometimes even >230 K) and form a sporadic sodium layer. Although not conclusive and highly uncertain, the icy dust reservoir model not only provides a good explanation for the observed characteristics of SSLs; it is also in good agreement with many other observations, such as the simultaneous sporadic sodium and iron layers, the behavior of SSLs on small time scale, the deviation of the sodium density profile of SSLs from the normal one, and the sharply decreased scale height above the peak of the sodium layer. These results further suggest that the icy dust might be a viable option of sodium reservoir for the formation of SSLs.

  2. DUST FORMATION IN MACRONOVAE

    SciTech Connect

    Takami, Hajime; Ioka, Kunihito; Nozawa, Takaya E-mail: kunihito.ioka@kek.jp

    2014-07-01

    We examine dust formation in macronovae (as known as kilonovae), which are the bright ejecta of neutron star binary mergers and one of the leading sites of r-process nucleosynthesis. In light of information about the first macronova candidate associated with GRB 130603B, we find that dust grains of r-process elements have difficulty forming because of the low number density of the r-process atoms, while carbon or elements lighter than iron can condense into dust if they are abundant. Dust grains absorb emission from ejecta with an opacity even greater than that of the r-process elements, and re-emit photons at infrared wavelengths. Such dust emission can potentially account for macronovae without r-process nucleosynthesis as an alternative model. This dust scenario predicts a spectrum with fewer features than the r-process model and day-scale optical-to-ultraviolet emission.

  3. Bright Dust Devil Tracks

    NASA Technical Reports Server (NTRS)

    2004-01-01

    9 June 2004 Martian dust devils sometimes disrupt thin coatings of surface dust to create dark streak patterns on the surface. However, not all dust devils make streaks, and not all dust devil streaks are dark. In Syria Planum, the streaks are lighter than the surrounding plains. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows an example from Syria near 8.8oS, 103.6oW. The thin coating of surface dust in this region is darker than the substrate beneath it. This is fairly unusual for Mars, because most dust is bright. This image covers an area about 3 km (1.9 mi) across and is illuminated by sunlight from the left/lower left.

  4. Sources and Evolution of Dust in the High Redshift Universe

    NASA Astrophysics Data System (ADS)

    Dwek, Eli

    2015-08-01

    Understanding the sources and evolution of dust in the very high redshift universe (z > 8-9) poses unique challenges to observers and theorists alike.The peak of the infrared emission from the dust falls in the ~ 80-120 micron region in the rest frame of the galaxy, or about 850 micron to 2 mm in the observers' frame. Sensitivity and background confusion are the main obstacles for the detection of these high-z galaxies and their association with optical and near-IR counterparts. Observations with instruments such as the SCUBA-2, AzTEC, Mambo, Laboca, and GISMO2 offer the best hope for detecting such sources.On the theoretical side, the sources of dust in these galaxies are confined to massive stars with main sequence lifetimes that are shorter than the age of the universe. This leaves core collapse supernovae (CCSNe) as the main source of thermally-condensed dust in these objects. Dust is not only produced by CCSNe, but also destroyed by them in the remnant phase of their evolution. Accounting for the mass of dust inferred from the far-IR/millimeter observations requires therefore an understanding of the various physical processes affecting the evolution of dust in the very high-z universe, and a carefull evaluation of the balance between their different dust formation and destruction mechanisms.

  5. The influence of soil remediation on lead in house dust.

    PubMed

    von Lindern, Ian H; Spalinger, Susan M; Bero, Bridget N; Petrosyan, Varduhi; von Braun, Margrit C

    2003-02-15

    Lead in house dust has long been recognized as a principal source of excess lead absorption among children at the Bunker Hill Superfund Site (BHSS) in northern Idaho. House dust lead concentration from homeowner's vacuum cleaner bags has been monitored since the epidemic of childhood lead poisoning in 1974. Geometric mean house dust lead concentrations decreased from >10000 mg/kg in 1974 to approximately 4000 mg/kg in 1975, in response to air pollution control initiatives at the defective primary lead smelter. After smelter closure, 1983 mean dust lead concentrations were near 3000 mg/kg and were most dependent on soil sources. Following emergency soil removals from public areas and roadsides and fugitive dust control efforts in the mid-1980s, house dust lead decreased by approximately 40-60% to 1200-1500 mg/kg. In 1992, a cleanup goal of 500 mg/kg dust lead community average, with no individual home exceeding 1000 mg/kg, was adopted. This goal was to be achieved by a combination of contaminated soil removals and fugitive dust control efforts throughout the 21 square mile BHSS. Continual reductions in house dust lead concentrations have been noted throughout the residential area soil cleanup. Geometric mean house dust lead concentrations averaged approximately 500-600 mg/kg from 1996 to 1999 and dropped below 500 mg/kg in 2000. Analysis of these data indicates that approximately 20% of the variance in dust lead concentrations is attributed to yard, neighborhood, and community soil lead concentrations. Since 1996, dust lead concentrations and dust and lead loading rates have also been measured by dust mats placed at entryways into the homes. Neighborhood soil lead concentrations, household hygiene, the number of adults living in the home, and the number of hours a child spends outdoors in summer explain approximately 26% of the variance in mat dust lead loading rates. It is estimated that post-remedial house dust lead concentrations will stabilize at 400-500 mg

  6. Overall characterization of cork dust explosion.

    PubMed

    Pilão, R; Ramalho, E; Pinho, C

    2006-05-20

    Explosibility and ignitability studies of air/cork dust mixtures were conducted in a near-spherical 22.7 L explosibility test chamber using pyrotechnic ignitors and in a furnace of 1.23 L. The suspension dust burned as air-dispersed dust clouds and the uniformity of the dispersion inside the chamber was evaluated through optical dust probes. The range of tested particle sizes went from a mass median diameter of 47.4 to 438.3 microm and the covered dust cloud concentration was up to 700-800 g/m(3). Measured explosion parameters included minimum explosible concentration, maximum explosion pressure, maximum rate of pressure rise and minimum autoignition temperature. The effect of dust particle size on flammability was evaluated and it was found that the minimum explosible concentration is around 40 g/m(3) and it is relatively independent of particle size below 180 microm. Maximum explosion pressure of 7.2 bar and maximum rate of pressure rise of 179 bar/s were detected for the smallest tested sizes. The limitations on the rates of devolatilization of the solid particles became rate controlling at high burning velocities, at high dust loadings and for large particle sizes. The effect of initial pressure on the characteristic parameters of the explosion was studied by varying the initial absolute pressure from 0.9 bar to 2.2 bar, and it was found that as initial pressure increases, there is a proportional increase of minimum explosion limit, maximum explosion pressure, and maximum rate of pressure rise. The influence of the intensity of the ignition energy on the development of the explosion was evaluated using ignition energies of 1000 J, 2500 J and 5000 J, and the experimental data showed that the value of 2500 J is the most convenient to use in the determination of minimum explosion concentration. The behavior of the cork dust explosion in hybrid methane air mixtures was studied for atmospheres with 2% and 3.5% (v/v) of methane. The effect of methane content on the

  7. Martian Arctic Dust Devil, Phoenix Sol 104

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Surface Stereo Imager on NASA's Phoenix Mars Lander caught this dust devil in action west-southwest of the lander at 11:16 a.m. local Mars time on Sol 104, or the 104th Martian day of the mission, Sept. 9, 2008.

    Dust devils have not been detected in any Phoenix images from earlier in the mission, but at least six were observed in a dozen images taken on Sol 104.

    Dust devils are whirlwinds that often occur when the Sun heats the surface of Mars, or some areas on Earth. The warmed surface heats the layer of atmosphere closest to it, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado.

    The dust devil visible in the center of this image just below the horizon is estimated to be about 400 meters (about 1,300 feet) from Phoenix, and 4 meters (13 feet) in diameter. It is much smaller than dust devils that have been observed by NASA's Mars Exploration Rover Spirit much closer to the equator. It is closer in size to dust devils seen from orbit in the Phoenix landing region, though still smaller than those.

    The image has been enhanced to make the dust devil easier to see.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  8. An experimental study of deflagration to detonation transition supported by dust layers

    SciTech Connect

    Li, Y.C.; Kauffman, C.W.; Sichel, M.

    1995-02-01

    The roles which dust layers play in severe dust explosions were investigated in a 70-m-long and 30-cm-diameter horizontal Flame Acceleration Tube (FAT) with one end closed and the other end open to the atmosphere. A variety of dusts such as corn dust, cornstarch, Mira Gel starch, wheat dust, and wood flour were layered on the bottom half of the FAT. Flame and detonation propagation parameters were closely monitored at different locations along the FAT. The study demonstrated that the moisture content of the dust, the exposed area of the dust layers to the convective flow, and the physical characteristics of the dust are the factors that most determine the severity of layered dust explosions, indicating that prelayered dust combustion is dominated by the dust/air mixing process. While the dust explosion rate constant K{sub st} can be used to characterize dust explosibility in predispersed dust in constant volume enclosures, it does not appear to characterize the behavior of layered dust explosions. Qualitative measurements of the variation of dust concentration during a layered dust explosion were obtained. The measurements indicated that the dust concentration at the time of flame arrival is highly nonuniform. The maximum pressure rise (P{sub max} {minus} P{sub 0}) within the FAT during a layered dust explosion was found to vary linearly with the flame velocity V{sub f} when V{sub f} is subsonic. As V{sub f} reaches supersonic values the maximum pressure increase was found to vary with the V{sub f}{sup 2}, the square of the flame velocity. This result was found to be independent of dust type and concentration.

  9. How Can Older Adults Prevent Falls?

    MedlinePlus

    ... Falls and Older Adults How Can Older Adults Prevent Falls? Past Issues / Winter 2014 Table of Contents ... healthy and happy. There are simple ways to prevent most falls. "Injuries from falls are a major ...

  10. Mars Global Surveyor TES Results: Observations of Atmospheric Dust During Mapping

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Pearl, J. C.; Conrath, B. J.; Christensen, P. R.

    1999-01-01

    The Mars Global Surveyor entered mapping orbit around Mars in March 1999. Infrared spectra returned by the Thermal Emission Spectrometer (TES) are very well suited for monitoring column-integrated infrared dust opacity. A global view of dust opacity is possible on a daily basis allowing the detailed study of the evolution of dust storms and the seasonal trend of the background dust opacity. Information about the vertical distribution of dust in the atmosphere can be obtained by examination of TES spectra taken in a limb-viewing geometry. We report here on 1) the observed horizontal distribution of dust aerosols and their evolution with time during the mapping phase of the Mars Global Surveyor mission so far (roughly covering northern hemisphere summer and early fall), and 2) the vertical distribution of dust aerosols as determined from TES spectra taken in the limb-viewing geometry.

  11. Dust Devil Tracks

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 8 May 2002) The Science This image, centered near 50.0 S and 17.7 W displays dust devil tracks on the surface. Most of the lighter portions of the image likely have a thin veneer of dust settled on the surface. As a dust devil passes over the surface, it acts as a vacuum and picks up the dust, leaving the darker substrate exposed. In this image there is a general trend of many of the tracks running from east to west or west to east, indicating the general wind direction. There is often no general trend present in dust devil tracks seen in other images. The track patterns are quite ephemeral and can completely change or even disappear over the course of a few months. Dust devils are one of the mechanisms that Mars uses to constantly pump dust into the ubiquitously dusty atmosphere. This atmospheric dust is one of the main driving forces of the present Martian climate. The Story Vrrrrooooooooom. Think of a tornado, the cartoon Tasmanian devil, or any number of vacuum commercials that powerfully suck up swirls of dust and dirt. That's pretty much what it's like on the surface of Mars a lot of the time. Whirlpools of wind called

  12. Cometary dust composition

    NASA Technical Reports Server (NTRS)

    Gehrz, R. D.; Hanner, M. S.

    1988-01-01

    The earth based measurements and in situ sampling of Comet Halley have provided new data about the chemical composition of cometary grains. Recent progress in laboratory studies of interplanetary dust particles (IDPs) complement the comet data, allowing inferences about the mineralogy and physical structure of the comet dust to be drawn from the observed elemental composition and infrared spectra. The in situ dust composition measurements at Halley, the composition of IDPs and their relation to comet dust, and the origin of the 3.4 micron hydrocarbon feature is discussed. Related discussion is also presented on aromatic components in comets and the 3.4 micron feature. These topics are briefly summarized.

  13. Operational Dust Prediction

    NASA Technical Reports Server (NTRS)

    Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; Jones, Luke; Lu, Sarah; Menut, Laurent; Morcrette, Jean-Jacques; Mulcahy, Jane; Nickovic, Slobodan; Garcia-Pando, Carlos P.; Reid, Jeffrey S.; Sekiyama, Thomas T.; Tanaka, Taichu Y.; Terradellas, Enric; Westphal, Douglas L.; Zhang, Xiao-Ye; Zhou, Chun-Hong

    2014-01-01

    Over the last few years, numerical prediction of dust aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. Dust prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to dust. Another limiting factor is the paucity of suitable dust observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of dust with examples from systems that are currently providing dust forecasts in near real-time or are part of international efforts to establish daily provision of dust forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of dust prediction activities and a historical perspective. Assimilation and evaluation aspects in dust prediction are also discussed.

  14. Tailored Prevention of Inpatient Falls

    PubMed Central

    ZUYEV, LYUBOV; BENOIT, ANGELA N.; CHANG, FRANK Y.; DYKES, PATRICIA C.

    2011-01-01

    Patient falls and fall-related injuries are serious problems in hospitals. The Fall TIPS application aims to prevent patient falls by translating routine nursing fall risk assessment into a decision support intervention that communicates fall risk status and creates a tailored evidence-based plan of care that is accessible to the care team, patients, and family members. In our design and implementation of the Fall TIPS toolkit, we used the Spiral Software Development Life Cycle model. Three output tools available to be generated from the toolkit are bed poster, plan of care, and patient education handout. A preliminary design of the application was based on initial requirements defined by project leaders and informed by focus groups with end users. Preliminary design partially simulated the paper version of the Morse Fall Scale currently used in hospitals involved in the research study. Strengths and weaknesses of the first prototype were identified by heuristic evaluation. Usability testing was performed at sites where research study is implemented. Suggestions mentioned by end users participating in usability studies were either directly incorporated into the toolkit and output tools, were slightly modified, or will be addressed during training. The next step is implementation of the fall prevention toolkit on the pilot testing units. PMID:20975543

  15. 1991 Fall Meeting Report

    NASA Astrophysics Data System (ADS)

    Chapman, David S.

    The AGU 1991 Fall Meeting, held in San Francisco December 9-13, was the largest national AGU meeting ever held. Meeting participation continued the steady growth trend set throughout the previous decade. A total of 4,037 papers and posters were presented, and by Friday noon of the meeting over 5,500 members had registered.Several special events were scheduled to inform and engage members on societal and programmatic aspects of our science. AGU's Committee on Education and Human Resources sponsored an open forum that addressed opportunities and problems associated with dual-career couples. A discussion of NASA's strategic plan by Berrien Moore and Joseph Alexander drew a large audience, and a special session on societal aspects of the Mt. Pinatubo eruption drew an overflow crowd. Two special lectures— “Plumes, Plates, and Deep Earth Structure” by Don L. Anderson and “New Frontiers in Aeronomy: Effects of Global Atmospheric Change” by P. M. Banks-also drew overflow crowds.

  16. 42 CFR 84.1142 - Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts, fumes, and mists having an air contamination level less... dusts, fumes, and mists having an air contamination level less than 0.05 milligram per cubic meter,...

  17. 42 CFR 84.1142 - Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts, fumes, and mists having an air contamination level less... dusts, fumes, and mists having an air contamination level less than 0.05 milligram per cubic meter,...

  18. 42 CFR 84.1142 - Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts, fumes, and mists having an air contamination level less... dusts, fumes, and mists having an air contamination level less than 0.05 milligram per cubic meter,...

  19. 42 CFR 84.1142 - Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts, fumes, and mists having an air contamination level less... dusts, fumes, and mists having an air contamination level less than 0.05 milligram per cubic meter,...

  20. 42 CFR 84.1142 - Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Isoamyl acetate tightness test; respirators designed for respiratory protection against dusts, fumes, and mists having an air contamination level less... dusts, fumes, and mists having an air contamination level less than 0.05 milligram per cubic meter,...

  1. ACAA 2006 fall meeting

    SciTech Connect

    2006-07-01

    The seven presentations (in pdf format) on the CD-ROM are: Amended Silicates{trademark}: mercury control without harming fly ash (J. Butz and others); benefits of gypsum in agriculture (L.D. Norton); co-firing biomass in pc fired units (C. Meijer and others); minimizing the impact of air pollution control equipment retrofits on saleability of fly ash (C.Weilert); new power plant construction - CCP readiness (T. Jansen); recent utilization of fly ash in coal plant construction (J. Liljegren and T. Hart); and resource conservation challenge (C. McLaughlin).

  2. Saharan dust levels in Greece and received inhalation doses

    NASA Astrophysics Data System (ADS)

    Mitsakou, C.; Kallos, G.; Papantoniou, N.; Spyrou, C.; Solomos, S.; Astitha, M.; Housiadas, C.

    2008-06-01

    The desert of Sahara is one of the major sources of mineral dust on Earth, producing around 2×108 tons/yr. Under certain weather conditions, dust particles from Saharan desert get transported over the Mediterranean Sea and most of Europe. The limiting values set by the directive EC/30/1999 of European Union can easily be exceeded by the transport of desert dust particles in all south European areas and especially urban. In this study, the effects of dust transport on air quality in several Greek urban areas are quantified. PM10 concentration values from stationary monitoring stations are compared to dust concentrations for the 4-year period 2003-2006. The dust concentration values in the Greek areas were estimated by the SKIRON modelling system coupled with embedded algorithms describing the dust cycle. The mean annual dust contribution to daily-averaged PM10 concentration values was found to be around or even greater than 10% in the urban areas throughout the years examined. Natural dust transport may contribute by much more than 20% to the annual number of exceedances - PM10 values greater than EU limits - depending on the specific monitoring location. In a second stage of the study, the inhaled lung dose received by the residents in various Greek locations is calculated. The particle deposition efficiency of mineral dust at the different parts of the human respiratory tract is determined by applying a lung dosimetry numerical model, which incorporates inhalation dynamics and aerosol physical processes. The inhalation dose from mineral dust particles was greater in the upper respiratory system (extrathoracic region) and less significant in the lungs, especially in the sensitive alveolar region. However, in cases of dust episodes, the amounts of mineral dust deposited along the human lung are comparable to those received during exposure in heavily polluted urban or smoking areas.

  3. Saharan dust levels in Greece and received inhalation doses

    NASA Astrophysics Data System (ADS)

    Mitsakou, C.; Kallos, G.; Papantoniou, N.; Spyrou, C.; Solomos, S.; Astitha, M.; Housiadas, C.

    2008-12-01

    The desert of Sahara is one of the major sources of mineral dust on Earth, producing around 2×108 tons/yr. Under certain weather conditions, dust particles from Saharan desert get transported over the Mediterranean Sea and most of Europe. The limiting values set by the directive EC/30/1999 of European Union can easily be exceeded by the transport of desert dust particles in the south European Region and especially in urban areas, where there is also significant contribution from anthropogenic sources. In this study, the effects of dust transport on air quality in several Greek urban areas are quantified. PM10 concentration values from stationary monitoring stations are compared to dust concentrations for the 4-year period 2003-2006. The dust concentration values in the Greek areas were estimated by the SKIRON modelling system coupled with embedded algorithms describing the dust cycle. The mean annual dust contribution to daily-averaged PM10 concentration values was found to be around or even greater than 10% in the urban areas throughout the years examined. Natural dust transport may contribute by more than 20% to the annual number of exceedances - PM10 values greater than EU limits - depending on the specific monitoring location. In a second stage of the study, the inhaled lung dose received by the residents in various Greek locations is calculated. The particle deposition efficiency of mineral dust at the different parts of the human respiratory tract is determined by applying a lung dosimetry numerical model, which incorporates inhalation dynamics and aerosol physical processes. The inhalation dose from mineral dust particles was greater in the upper respiratory system (extrathoracic region) and less significant in the lungs, especially in the sensitive alveolar region. However, in cases of dust episodes, the amounts of mineral dust deposited along the human lung are comparable to those received during exposure in heavily polluted urban or smoking areas.

  4. Desert Dust Satellite Retrieval Intercomparison

    NASA Technical Reports Server (NTRS)

    Carboni, E.; Thomas, G. E.; Sayer, A. M.; Siddans, R.; Poulsen, C. A.; Grainger, R. G.; Ahn, C.; Antoine, D.; Bevan, S.; Braak, R.; Brindley, H.; DeSouza-Mchado, S.; Deuze, J. L.; Diner, D.; Ducos, F.; Grey, W.; Hsu, C.; Kalashnikova, O. V.; Kahn, R.; North, P. R. J.; Salustro, C.; Smith, A.; Tanre, D.; Torres, O.; Veihelmann, B.

    2012-01-01

    This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim is to identify and understand the differences between current algorithms, and hence improve future retrieval algorithms. The satellite instruments considered are AATSR, AIRS, MERIS, MISR, MODIS, OMI, POLDER, and SEVIRI. An interesting aspect is that the different algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. These include multi-angle approaches (MISR, AATSR), polarisation measurements (POLDER), single-view approaches using solar wavelengths (OMI, MODIS), and the thermal infrared spectral region (SEVIRI, AIRS). Differences between instruments, together with the comparison of different retrieval algorithms applied to measurements from the same instrument, provide a unique insight into the performance and characteristics of the various techniques employed. As well as the intercomparison between different satellite products, the AODs have also been compared to co-located AERONET data. Despite the fact that the agreement between satellite and AERONET AODs is reasonably good for all of the datasets, there are significant differences between them when compared to each other, especially over land. These differences are partially due to differences in the algorithms, such as as20 sumptions about aerosol model and surface properties. However, in this comparison of spatially and temporally averaged data, at least as significant as these differences are sampling issues related to the actual footprint of each instrument on the heterogeneous aerosol field, cloud identification and the quality control flags of each dataset.

  5. Whither Cometary Dust?

    NASA Astrophysics Data System (ADS)

    Lisse, Carey M.

    2010-10-01

    In this paper I will discuss recent findings that have important implications for our understanding of the formation and evolution of primitive solar system dust, including: - Nesvorny et al. (2010), following up on their dynamical analyses of the zodiacal dust bands as sourced by the breakup of the Karin (5Mya) and Veritas (8Mya) asteroid families, argue that over 90% of the interplanetary dust cloud at 1 AU comes from JFC comets with near-circularized, low inclination orbits. This implies that the noted IPD collections of anhydrous and hydrous dust particles are likely to be from Oort cloud and JFC comets, respectively, not from asteroids and comets as thought in the past. Hydrous dust particles from comets like 85P/Wild2 and 9P/Tempel 1 would be consistent with results from the STARDUST and Deep Impact experiments. - Estimates of the dust particle size distributions (PSDs) in the comae of 85P/Wild2 (Green et al. 2004, 2007) and 73P/SW-3 (Sitko et al. 2010, Vaubaillon & Reach 2010) and in the trails of comets (Reach et al. 2007) have broken power law structure, with a plateau enhancement of particles of 1 mm - 1 cm in size. This size is also the size of most chondritic inclusions, and the predicted size range of the "aggregational barrier", where collisions between dust particles become destructive. - Studies of the albedo and polarization properties of cometary dust (Kolokolova et al. 2007) suggest there are 2 major groupings, one with low scattering capability and one with high. While these families could possibly have been explained by systematics in the PSDs of the emitted dust, independent work by Lisse et al. (2008) on the mineralogy of a number of highly dusty comets has shown evidence for one family of comets with highly crystalline dust and another with highly amorphous dust.

  6. Mixing of Asian dust with pollution aerosol and the transformation of aerosol components during the dust storm over China in spring 2007

    NASA Astrophysics Data System (ADS)

    Huang, Kan; Zhuang, Guoshun; Li, Juan; Wang, Qiongzhen; Sun, Yele; Lin, Yanfen; Fu, Joshua S.

    2010-04-01

    An intensive spring aerosol sampling campaign over northwestern and northern China and a megacity in eastern China was conducted in the spring of 2007 to investigate the mixing of Asian dust with pollution aerosol during its long-range transport. On the basis of the results of the three sites near dust source regions (Tazhong, Yulin, and Duolun) and a metropolitan city (Shanghai), three dust sources, i.e., the western high-Ca dust in the Taklimakan Desert, the northwestern high-Ca dust and the northeastern low-Ca dust in Mongolia Gobi, were identified on the basis of the air mass trajectories and the elemental tracer analysis (e.g., Ca/Al, SO42-/S, Ca2+/Ca, and Na+/Na). The western dust was least polluted in comparison to the other two dust sources. The results evidently indicated that the dust could have already mixed with pollution aerosol even in near dust source regions. The concentrations of As, Cd, Cu, Pb, Zn, and S were elevated several times at all sites during dust days, showing the entrainment of pollution elements by dust. The secondary SO42- was observed to show much higher concentration due to the heterogeneous reaction on the alkaline dust during dust storm, while the concentrations of NO3- and NH4+ decreased owing to the dilution of the local pollution by the invaded dust. The western dust contained relatively low anthropogenic aerosols, and it mainly derived from the Taklimakan Desert, a paleomarine source. The northwestern dust had a considerable chemical reactivity and mixing with sulfur precursors emitted from the coal mines on the pathway of the long-range transport of dust. The northeastern dust reached Shanghai with high acidity, and it became the mixed aerosol with the interaction among dust, local pollutants, and sea salts. Comparison of the speciation of the water-soluble ions on both nondust and dust days at all sites illustrated the evolution of major ion species from different dust sources during the long-range transport of dust. The

  7. Investigating the causes of airborne dust in Western United States

    NASA Astrophysics Data System (ADS)

    Kavouras, I. G.; Etyemezian, V.; Xu, J.; Dubois, D.; Pitchford, M.; Green, M.

    2005-12-01

    Dust is a principal component of haze at many of the Western Class I Areas as defined by the Clean Air Act (CAA) adopted by the US congress on 1977. The magnitude of the impact of dust on haze varies by region as well as by season due to source variations in spatial scale, time, location, and causes of emission. Windblown dust emissions occur on both local and regional scales and the magnitude of dust emissions depends on man-made activities, soil properties and meteorology. On a transcontinental scale, enormous, regional dust storms can be transported across oceans and continents and impact the entire western United States. The target of this study was to specifically identify the causes of dust measured in the Class I areas of the western states by developing a methodology for assigning worst-case visibility days when dust was the major component at IMPROVE monitors within the WRAP domain to a set of source-categories over the period 2001 - 2003. The methodology included the development and implementation of the following tools: (i) concentration diagnostic ratios; (ii) multivariate linear regression analysis; (iii) air masses backward trajectories analysis; (iv) land use characteristics and; (v) soil properties. Each day was attributed to: (i) Transcontinental transport of large scale events from Asia; (ii) Small scale local windblown dust events; (iii) A combination of local and regional windblown dust events; (iv) Upwind transport and (v) Other unknown sources. The study included 71 sites from the IMPROVE network located in the Western Regional Air Partnership (WRAP) domain. Meteorological data including wind speed and direction and, precipitation (if available) were retrieved from meteorological stations in the vicinity of the IMPROVE monitors and used to estimate the contribution of "locally" generated windblown dust to visibility impairment. The spatial and temporal variation of the number of days attributed to the aforementioned source-categories was

  8. The Nature of Interstellar Dust

    NASA Technical Reports Server (NTRS)

    Huss, G. R.

    2003-01-01

    The STARDUST mission is designed to collect dust the coma of comet Wild 2 and to collect interstellar dust on a second set of collectors. We have a reasonable idea of what to expect from the comet dust collection because the research community has been studying interplanetary dust particles for many years. It is less clear what we should expect from the interstellar dust. This presentation discusses what we might expect to find on the STARDUST interstellar dust collector.

  9. A consideration of the effects of dust aerosol and surface dust on Snowball Earth deglaciation

    NASA Astrophysics Data System (ADS)

    Abbot, D. S.; Halevy, I.; Pierrehumbert, R.

    2009-12-01

    Most previous global climate model simulations could only produce the termination of Snowball Earth episodes at CO2 partial pressures of several tenths of a bar, which is roughly an order of magnitude higher than recent estimates of CO2 levels during and shortly after Snowball events. These simulations have neglected the impact of surface dust on the ice albedo and dust aerosols on radiative transfer, which is an assumption of potentially grave importance. We argue, using the Dust Entrainment and Deposition (DEAD) box model driven by GCM results, that increased dust source and decreased dust sink during Snowball Earth events would have combined to produce atmospheric dust aerosol concentrations one to two orders of magnitude higher than today. We perform calculations using NCAR's Single Column Atmospheric Model (SCAM), a radiative-convective model with sophisticated aerosol, cloud, and radiative parameterizations, that show that when the surface albedo is high, increases of roughly one order of magnitude in dust aerosol loading can produce several times more surface warming than an increase in pCO2 from 10^-4 to 10^-1 bar. Additionally, we argue that over the lifetime of a Snowball event, ice dynamics should lead to the development of a layer of continental and volcanic dust at the ice surface in the tropics that would significantly lower the tropical surface albedo and encourage deglaciation. We test this idea by running the FOAM and CAM GCMs with an added tropical dust layer of different sizes and albedos and find that the tropical dust layer causes Snowball deglaciation at pCO2 values consistent with observations in a reasonable regime of these parameters. Therefore we conclude that including dust processes in simulations can reconcile the CO2 levels required for Snowball termination in climate models with observations. Surface air temperature as a function of the surface albedo, pCO2 and dust loading. The dust profile is either the modern tropical average

  10. Combustible dust tests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sugar dust explosion in Georgia on February 7, 2008 killed 14 workers and injured many others (OSHA, 2009). As a consequence of this explosion, OSHA revised its Combustible Dust National Emphasis (NEP) program. The NEP targets 64 industries with more than 1,000 inspections and has found more tha...

  11. Pathfinder Spies Dust Devils

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This set of images from NASA's 1997 Pathfinder mission highlight the dust devils that gust across the surface of Mars. The right image shows the dusty martian sky as our eye would see it. The left image has been enhanced to expose the dust devils that lurk in the hazy sky.

  12. Dust resuspension without saltation

    PubMed Central

    Loosmore, Gwen A.; Hunt, James R.

    2010-01-01

    Wind resuspension (or entrainment) provides a source of dust and contaminants for the atmosphere. Conventional wind erosion models parameterize dust resuspension flux with a threshold velocity or with a horizontal abrasion flux; in the absence of abrasion the models assume dust flux is transient only. Our experiments with an uncrusted, fine material at relative humidities exceeding 40% show a long-term steady dust flux in the absence of abrasion, which fits the approximate form: Fd = 3.6(u*)3, where Fd is the dust flux (in μg/m2 s), and u* is the friction velocity (in m/s). These fluxes are generally too small to be significant sources of dust in most models of dust emission. However, they provide a potential route to transport contaminants into the atmosphere. In addition, dust release is substantial during the initial transient phase. Comparison with field data suggests that the particle friction Reynolds number may prove a better parameter than u* for correlating fluxes and understanding the potential for abrasion. PMID:20336175

  13. Toxicity of lunar dust

    NASA Astrophysics Data System (ADS)

    Linnarsson, Dag; Carpenter, James; Fubini, Bice; Gerde, Per; Karlsson, Lars L.; Loftus, David J.; Prisk, G. Kim; Staufer, Urs; Tranfield, Erin M.; van Westrenen, Wim

    2012-12-01

    The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of substantial research efforts, lunar dust properties, and therefore lunar dust toxicity may differ substantially. In this contribution, past and ongoing work on dust toxicity is reviewed, and major knowledge gaps that prevent an accurate assessment of lunar dust toxicity are identified. Finally, a range of studies using ground-based, low-gravity, and in situ measurements is recommended to address the identified knowledge gaps. Because none of the curated lunar samples exist in a pristine state that preserves the surface reactive chemical aspects thought to be present on the lunar surface, studies using this material carry with them considerable uncertainty in terms of fidelity. As a consequence, in situ data on lunar dust properties will be required to provide ground truth for ground-based studies quantifying the toxicity of dust exposure and the associated health risks during future manned lunar missions.

  14. Automatic Fall Monitoring: A Review

    PubMed Central

    Pannurat, Natthapon; Thiemjarus, Surapa; Nantajeewarawat, Ekawit

    2014-01-01

    Falls and fall-related injuries are major incidents, especially for elderly people, which often mark the onset of major deterioration of health. More than one-third of home-dwelling people aged 65 or above and two-thirds of those in residential care fall once or more each year. Reliable fall detection, as well as prevention, is an important research topic for monitoring elderly living alone in residential or hospital units. The aim of this study is to review the existing fall detection systems and some of the key research challenges faced by the research community in this field. We categorize the existing platforms into two groups: wearable and ambient devices; the classification methods are divided into rule-based and machine learning techniques. The relative merit and potential drawbacks are discussed, and we also outline some of the outstanding research challenges that emerging new platforms need to address. PMID:25046016

  15. Nature, structure, and properties of asbestos cement dust

    PubMed Central

    Baeten, J; Helsen, J; Deruyttere, A

    1980-01-01

    ABSTRACT Total dust samples produced by machining three commercial asbestos-cement products (autoclaved sheet, non-autoclaved sheet, pipe) were examined for their dimensional, surface, and physicochemical characteristics. Microscopic inspection of dust fractions with different settling characteristics in air allowed determination of the simple dimensional features that apply to respirable fibres—that is, the true diameter, length, and aspect ratio and the coil diameter, coil length, and coil aspect ratio. The respirable fraction as a percentage of the total dust varied with the type of machined product: 8·5% for non-autoclaved sheet, 10·5% for autoclaved sheet, and 35% for pipe. Quantitative x-ray diffraction of different granulometric fractions showed that the asbestos content decreases with fraction size (thus the asbestos content will change with distance from the dust source). Electron microscopic examination of fine dust (aerodynamic diameter < 7 μm) showed that only about 10% of the inspected particles were optically virgin. From these observations it has been calculated that the threshold limit value of 2 fibres per cm3 of air corresponds to a total dust concentration of 1·2, 0·6, and 0·1 mg/m3 and to a maximum admissible respirable dust content of 0·1, 0·06, and 0·04 mg/m3 for non-autoclaved sheet, autoclaved sheet, and pipe respectively. The surface of optically virgin fibres may still be contaminated by calcium containing particles, as shown by analytical transmission and scanning electron microscope. Dust from the autoclaved product contains fewer calcium coated fibres. The physicochemical behaviour of dust, as shown by dissolution kinetics and absorption of carcinogens from tobacco smoke, is comparable to the behaviour of cement rather than of pure asbestos. In general, asbestos cement dust differs consistently from pure asbestos. Conclusions, drawn from studies on pure asbestos, cannot be applied as such to asbestos cement dust. Images PMID

  16. Spirit Captures Two Dust Devils On the Move

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1 Annotated

    At the Gusev site recently, skies have been very dusty, and on its 421st sol (March 10, 2005) NASA's Mars Exploration Rover Spirit spied two dust devils in action. This is an image from the rover's navigation camera.

    Views of the Gusev landing region from orbit show many dark streaks across the landscape -- tracks where dust devils have removed surface dust to show relatively darker soil below -- but this is the first time Spirit has photographed an active dust devil.

    Scientists are considering several causes of these small phenomena. Dust devils often occur when the Sun heats the surface of Mars. Warmed soil and rocks heat the layer of atmosphere closest to the surface, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado. Another possibility is that a flow structure might develop over craters as wind speeds increase. As winds pick up, turbulence eddies and rotating columns of air form. As these columns grow in diameter they become taller and gain rotational speed. Eventually they become self-sustaining and the wind blows them down range.

    One sol before this image was taken, power output from Spirit's solar panels went up by about 50 percent when the amount of dust on the panels decreased. Was this a coincidence, or did a helpful dust devil pass over Spirit and lift off some of the dust?

    By comparing the separate images from the rover's different cameras, team members estimate that the dust devils moved about 500 meters (1,640 feet) in the 155 seconds between the navigation camera and hazard-avoidance camera frames; that equates to about 3 meters per second (7 miles per hour). The dust devils appear to be about 1,100 meters (almost three-quarters of a mile) from the rover.

  17. Transmission through air as a possible route of exposure for MRSA.

    PubMed

    Bos, Marian E H; Verstappen, Koen M; van Cleef, Brigitte A G L; Dohmen, Wietske; Dorado-García, Alejandro; Graveland, Haitske; Duim, Birgitta; Wagenaar, Jaap A; Kluytmans, Jan A J W; Heederik, Dick J J

    2016-05-01

    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is highly prevalent in pigs and veal calves. The environment and air in pig and veal calf barns is often contaminated with LA-MRSA, and can act as a transmission source for humans. This study explores exposure-response relationships between sequence type 398 (ST398) MRSA air exposure level and nasal ST398 MRSA carriage in people working and/or living on farms. Samples and data were used from three longitudinal field studies in pig and veal calf farm populations. Samples consisted of nasal swabs from the human participants and electrostatic dust fall collectors capturing airborne settled dust in barns. In both multivariate and mutually adjusted analyses, a strong association was found between nasal ST398 MRSA carriage in people working in the barns for >20 h per week and MRSA air levels. In people working in the barns < 20 h per week there was a strong association between nasal carriage and number of working hours. Exposure to ST398 MRSA in barn air seems to be an important determinant for nasal carriage, especially in the highly exposed group of farmers, next to duration of contact with animals. Intervention measures should therefore probably also target reduction of ST398 MRSA air levels. PMID:25515375

  18. Direct Observations of Heterogeneous Dust Processing in the Troposphere: Ambient Measurements, Source Compositions and Laboratory Studies

    NASA Astrophysics Data System (ADS)

    Sullivan, R. C.; Guazzotti, S.; Sodeman, D.; Coffee, K.; Holecek, J.; Spencer, M.; Prather, K. A.

    2004-12-01

    The size and chemical composition of single dust particles in both background marine air and during dust events was determined using Aerosol Time-of-Flight Mass Spectrometry (ATOFMS) throughout the Indian and Pacific Oceans and Pacific coast during three major field campaigns: INDOEX, ACE-Asia and CIFEX. In general the chemical associations within individual particle spectra for the major dust particle types were very similar in all sampling locations. The dust mass spectra were dominated by various combinations of potassium, calcium, iron, and aluminum, with contributions from silicates, sodium, chloride and titanium oxides. The relative ion intensities often differed suggesting that the dust is a complex, externally mixed aggregate of varying mineral origins. Evidence of heterogeneous processing of the dust particles was also observed with ATOFMS using markers for nitrate, sulphate, and organic species. Aging of dust particles can dramatically alter their radiative and cloud-forming properties, changing the effects that dust will have on global climate. The dust spectra were also compared with those measured from collected dust, sand and soil samples in Asia and the United States. In general the mass spectra of the ambient and source dust particles were very similar, except that for the most part the source samples lacked evidence of atmospheric aging. Preliminary lab studies examining heterogeneous processing of dust in a flow tube will be presented. These studies investigate the relative reactivity of the different types of dust observed in the atmosphere and the competitive heterogeneous chemistry of dust and sea salt particles.

  19. Dust Spectroscopy and the Nature of Grains

    NASA Technical Reports Server (NTRS)

    Tielens, A. G. G. M.

    2006-01-01

    Ground-based, air-borne and space-based, infrared spectra of a wide variety of objects have revealed prominent absorption and emission features due to large molecules and small dust grains. Analysis of this data reveals a highly diverse interstellar and circumstellar grain inventory, including both amorphous materials and highly crystalline compounds (silicates and carbon). This diversity points towards a wide range of physical and chemical birthsites as well as a complex processing of these grains in the interstellar medium. In this talk, I will review the dust inventory contrasting and comparing both the interstellar and circumstellar reservoirs. The focus will be on the processes that play a role in the lifecycle of dust in the interstellar medium.

  20. Automatic fall detectors and the fear of falling.

    PubMed

    Brownsell, Simon; Hawley, Mark S

    2004-01-01

    We studied the effect of automatic fall detection units on the fear of falling. Participants were community alarm users living in the community aged over 75 years or those aged 60-74 years who had experienced a fall in the previous six months. Of those approached, 31% consented to take part; the main reason given for potential participants declining involvement was that they were happy with the technology they already had. Subjects were assigned to a control group (n = 21) or intervention group (n = 34) based on age, the number of self-reported falls in the previous six months and their score on the self-administered Falls Efficacy Scale (FES), which measures fear of falling on a scale of 0-100, with higher scores indicating less fear. The monitoring period lasted a mean of 17 weeks (SD 3.1). There was no significant difference between the intervention and control groups in their mean ratings of fear of falls (40.3 vs 37.5, difference 2.8, 95% CI 6.2 to 11.8), health-related quality of life or morale. Differences in fear of falling between an intervention subgroup who wore their detector at least occasionally (62%) and those who did not (38%) suggested that some people may benefit from a fall detector while others may lose confidence if they are provided with one. Most users who wore their detectors at least occasionally felt more confident and independent and considered that the detector improved their safety. PMID:15494083

  1. The lunar dust pendulum

    NASA Astrophysics Data System (ADS)

    Collier, Michael R.; Farrell, William M.; Stubbs, Timothy J.

    2013-07-01

    An analytic model for the motion of a positively charged lunar dust grain in the presence of a shadowed crater at a negative potential in vacuum is presented. It is shown that the dust grain executes oscillatory trajectories, and an expression is derived for the period of oscillation. Simulations used to verify the analytic expression also show that because the trajectories are unstable, dust grains are either ejected from the crater's vicinity or deposited into the crater forming "dust ponds." The model also applies to other airless bodies in the solar system, such as asteroids, and predicts that under certain conditions, particularly near lunar sunset, oscillating dust "canopies" or "swarms" will form over negatively charged craters.

  2. Dust escape from Io

    NASA Astrophysics Data System (ADS)

    Flandes, Alberto

    2004-08-01

    The Dust ballerina skirt is a set of well defined streams composed of nanometric sized dust particles that escape from the Jovian system and may be accelerated up to >=200 km/s. The source of this dust is Jupiter's moon Io, the most volcanically active body in the Solar system. The escape of dust grains from Jupiter requires first the escape of these grains from Io. This work is basically devoted to explain this escape given that the driving of dust particles to great heights and later injection into the ionosphere of Io may give the particles an equilibrium potential that allow the magnetic field to accelerate them away from Io. The grain sizes obtained through this study match very well to the values required for the particles to escape from the Jovian system.

  3. Lunar Dust Mitigation Screens

    NASA Astrophysics Data System (ADS)

    Knutson, Shawn; Holloway, Nancy

    With plans for the United States to return to the moon, and establish a sustainable human presence on the lunar surface many issues must be successfully overcome. Lunar dust is one of a number of issues with the potential to create a myriad of problems if not adequately addressed. Samples of dust brought back from Apollo missions show it to be soft, yet sharp and abrasive. The dust consists of a variety of morphologies including spherical, angular blocks, shards, and a number of irregular shapes. One of the main issues with lunar dust is its attraction to stick to anything it comes in contact with (i.e. astronauts, equipment, habitats, etc.). Ionized radiation from the sun strikes the moon's surface and creates an electrostatic charge on the dust. Further, the dust harbors van der Waals forces making it especially difficult to separate once it sticks to a surface. During the Apollo missions, it was discovered that trying to brush the lunar dust from spacesuits was not effective, and rubbing it caused degradation of the suit material. Further, when entering the lunar module after moonwalks, the astronauts noted that the dust was so prolific inside the cabin that they inhaled and ingested it, causing at least one of them, Harrison "Jack" Schmidt, to report irritation of the throat and lungs. It is speculated that the dust could also harm an astronaut's nervous and cardiovascular systems, especially during an extended stay. In addition to health issues, the dust can also cause problems by scouring reflective coatings off of thermal blankets, and roughening surfaces of windows and optics. Further, panels on solar cells and photovoltaics can also be compromised due to dust sticking on the surfaces. Lunar dust has the capacity to penetrate seals, interfere with connectors, as well as mechanisms on digging machines, all of which can lead to problems and failure. To address lunar dust issues, development of electrostatic screens to mitigate dust on sur-faces is currently

  4. Loire Dust Devil

    NASA Technical Reports Server (NTRS)

    2005-01-01

    25 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an active dust devil making its way across the rugged terrain of the Loire Vallis system. The dust devil, seen as a fuzzy, nearly-circular bright feature near the center of the picture, is casting a shadow toward the right/upper right (east/northeast). Unlike some martian dust devils, this one did not make a dark streak on the ground. Many more dust devils occur on Mars than there are dust devil streaks observed on the planet's surface.

    Location near: 18.2oS, 16.5oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Spring

  5. Isidis Dust Devil

    NASA Technical Reports Server (NTRS)

    2004-01-01

    10 March 2004 This arrow in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image points to an active dust devil observed in Isidis Planitia near 18.3oN, 268.9oW. The columnar shadow of the dust devil is visible, as is a pencil-thin (at least, pencil-thin at the scale of the image) line created by the vortex as it disrupted the dust that coats the surface. The streak indicates that the dust devil had already traveled more than 3 kilometers (1.9 miles), over craters, large ripples, and ridges, before the MOC took this picture. The dust devil was moving from the northeast (upper right) toward the southwest (lower left). Sunlight illuminates the scene from the lower left; the image covers an area 3 km (1.9 mi) wide.

  6. Far-Reaching Impacts of African Dust- A Calipso Perspective

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Chin, Mian; Yuan, Tianle; Bian, Huisheng; Prospero, Joseph; Omar, Ali; Remer, Lorraine; Winker, David; Yang, Yuekui; Zhang, Yan; Zhang, Zhibo

    2014-01-01

    .6 and 2.5 for the deposition to the tropical Atlantic and Amazon, respectively. The MODIS-based estimates appear to fall within the range of CALIPSO-based estimates; and the difference between MODIS and CALIPSO estimates can be largely attributed to the interannual variability, which is corroborated by long-term surface dust concentration observations in the tropical Atlantic. Considering that CALIPSO generally tends to underestimate the aerosol loading, our estimate is likely to represent a low bound for the dust transport and deposition estimate. The finding suggests that models have substantial biases and considerable effort is needed to improve model simulations of dust cycle.

  7. Cowlitz Falls Fish Passage.

    SciTech Connect

    1995-09-01

    The upper Cowlitz was once home to native salmon and steelhead. But the combined impacts of overharvest, farming, logging and road building hammered fish runs. And in the 1960s, a pair of hydroelectric dams blocked the migration path of ocean-returning and ocean-going fish. The lower Cowlitz still supports hatchery runs of chinook, coho and steelhead. But some 200 river miles in the upper river basin--much of it prime spawning and rearing habitat--have been virtually cut off from the ocean for over 26 years. Now the idea is to trap-and-haul salmon and steelhead both ways and bypass previously impassable obstacles in the path of anadromous fish. The plan can be summarized, for the sake of explanation, in three steps: (1) trap and haul adult fish--collect ocean-returning adult fish at the lowermost Cowlitz dam, and truck them upstream; (2) reseed--release the ripe adults above the uppermost dam, and let them spawn naturally, at the same time, supplement these runs with hatchery born fry that are reared and imprinted in ponds and net pens in the watershed; (3) trap and haul smolts--collection the new generation of young fish as they arrive at the uppermost Cowlitz dam, truck them past the three dams, and release them to continue their downstream migration to the sea. The critical part of any fish-collection system is the method of fish attraction. Scientists have to find the best combination of attraction system and screens that will guide young fish to the right spot, away from the turbine intakes. In the spring of 1994 a test was made of a prototype system of baffles and slots on the upriver face of the Cowlitz Falls Dam. The prototype worked at 90% efficiency in early tests, and it worked without the kind of expensive screening devices that have been installed on other dams. Now that the success of the attraction system has been verified, Harza engineers and consultants will design and build the appropriate collection part of the system.

  8. Signaling Pathways Involved in Lunar Dust Induced Cytotoxicity

    NASA Technical Reports Server (NTRS)

    Zhang, Ye; Lam, Chiu-Wing; Scully, Robert R.; Williams, Kyle; Zalesak, Selina; Wu, Honglu; James, John T.

    2014-01-01

    The Moon's surface is covered by a layer of fine, reactive dust. Lunar dust contain about 1-2% of very fine dust (< 3 micron), that is respirable. The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dust-induced changes of the expression of fibrosis-related genes, and to identify specific signaling pathways involved in lunar dust-induced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose-only inhalation chambers to concentrations of 0 (control air), 2.1, 6.1, 21, and 61 mg/m(exp 3) of lunar dust. Five rats per group were euthanized 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The total RNAs were isolated from the blood or lung tissue after being lavaged, using the Qigen RNeasy kit. The Rat Fibrosis RT2 Profile PCR Array was used to profile the expression of 84 genes relevant to fibrosis. The genes with significant expression changes are identified and the gene expression data were further analyzed using IPA pathway analysis tool to determine the signaling pathways with significant changes.

  9. Desert dust suppressing precipitation: A possible desertification feedback loop

    PubMed Central

    Rosenfeld, Daniel; Rudich, Yinon; Lahav, Ronen

    2001-01-01

    The effect of desert dust on cloud properties and precipitation has so far been studied solely by using theoretical models, which predict that rainfall would be enhanced. Here we present observations showing the contrary; the effect of dust on cloud properties is to inhibit precipitation. Using satellite and aircraft observations we show that clouds forming within desert dust contain small droplets and produce little precipitation by drop coalescence. Measurement of the size distribution and the chemical analysis of individual Saharan dust particles collected in such a dust storm suggest a possible mechanism for the diminished rainfall. The detrimental impact of dust on rainfall is smaller than that caused by smoke from biomass burning or anthropogenic air pollution, but the large abundance of desert dust in the atmosphere renders it important. The reduction of precipitation from clouds affected by desert dust can cause drier soil, which in turn raises more dust, thus providing a possible feedback loop to further decrease precipitation. Furthermore, anthropogenic changes of land use exposing the topsoil can initiate such a desertification feedback process. PMID:11353821

  10. The Influence of Dust-radiation-microphysics Processes on Tropical Cyclone Development

    NASA Astrophysics Data System (ADS)

    Chen, S.; Cheng, C.; Chen, J.; Lin, Y.; Lee, H.; Tsai, I.

    2011-12-01

    Saharan dust can modify the Saharan Air Layer (SAL) and its environment by changing the energy budget through direct and indirect radiative forcing. Scattering and absorption of radiation by suspended dust directly modifies the energy budget in the atmosphere and at the surface. Smaller dust particles can remain suspended in the air for prolonged periods and propagate over the Atlantic Ocean along with SAL. These fine particles can reach an altitude of 8-9 km, where they nucleate ice crystals and transform cloud microphysical properties, indirectly changing the energy budget. Thus, the dust within the air mass is likely to affect the evolution of hurricane properties, life cycles, and the corresponding cloud systems through the dust-cloud-radiation interactions. A tracer model based on the Weather Research and Forecasting model (named WRFT) was developed to study the influence of dust-radiation-microphysics effects on hurricane activities. The dust-radiation effects and a two-moment microphysics scheme with dust particles acting as ice nuclei were implemented into WRFT. In this work, two easterly waves, which were precursors of Tropical Storm Debby and Hurricane Ernesto, during 18-25 August 2006 were studied. Four high-resolution numerical experiments were conducted with the combinations of activating/deactivating dust-radiation and/or dust-microphysics processes. Results from these four experiments are compared to investigate the influence of dust-radiation-microphysics processes on these two storm developments.

  11. Measurement of Fugitive Dust Emissions and Visible Emissions.

    ERIC Educational Resources Information Center

    McKee, Herbert C.

    The method of measuring fugitive dust emission utilized by the Texas Air Control Board is described in this presentation for the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971. The measuring procedure, precautions, expected results, and legal acceptance of the method are…

  12. 40 CFR 63.1544 - Standards for fugitive dust sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants for Primary Lead Smelting § 63.1544 Standards for fugitive dust sources. (a) Each owner or operator of a primary lead smelter shall prepare, and at all times...

  13. 40 CFR 63.1544 - Standards for fugitive dust sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants for Primary Lead Smelting § 63.1544 Standards for fugitive dust sources. (a) Each owner or operator of a primary lead smelter shall prepare, and at all times...

  14. Ultraviolet Radiative Transfer Modeling of Nearby Galaxies with Extraplanar Dusts

    NASA Astrophysics Data System (ADS)

    Shinn, Jong-Ho; Seon, Kwang-Il

    2015-12-01

    In order to examine their relation to the host galaxy, the extraplanar dusts of six nearby galaxies are modeled, employing a three-dimensional Monte Carlo radiative transfer code. The targets are from the highly inclined galaxies that show dust-scattered ultraviolet halos, and the archival Galaxy Evolution Explorer FUV band images were fitted with the model. The observed images are generally well-reproduced by two dust layers and one light source layer, whose vertical and radial distributions have exponential profiles. We obtained several important physical parameters, such as star formation rate (SFRUV), face-on optical depth, and scale-heights. Three galaxies (NGC 891, NGC 3628, and UGC 11794) show clear evidence for the existence of an extraplanar dust layer. However, it is found that the remaining three targets (IC 5249, NGC 24, and NGC 4173) do not necessarily need a thick dust disk to model the ultraviolet (UV) halo, because its contribution is too small and the UV halo may be caused by the wing part of the GALEX point spread function. This indicates that the galaxy samples reported to have UV halos may be contaminated by galaxies with negligible extraplanar (halo) dust. The galaxies showing evidence of an extraplanar dust layer fall within a narrow range on the scatter plots between physical parameters such as SFRUV and extraplanar dust mass. Several mechanisms that could possibly produce the extraplanar dust are discussed. We also found a hint that the extraplanar dust scale-height might not be much different from the polycyclic aromatic hydrocarbon emission characteristic height.

  15. Dust Combustion Safety Issues for Fusion Applications

    SciTech Connect

    L. C. Cadwallader

    2003-05-01

    This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

  16. Radar fall detectors: a comparison

    NASA Astrophysics Data System (ADS)

    Erol, Baris; Amin, Moeness; Ahmad, Fauzia; Boashash, Boualem

    2016-05-01

    Falls are a major cause of accidents in elderly people. Even simple falls can lead to severe injuries, and sometimes result in death. Doppler fall detection has drawn much attention in recent years. Micro-Doppler signatures play an important role for the Doppler-based radar systems. Numerous studies have demonstrated the offerings of micro-Doppler characteristics for fall detection. In this respect, a plethora of micro-Doppler signature features have been proposed, including those stemming from speech recognition and wavelet decomposition. In this work, we consider four different sets of features for fall detection. These can be categorized as spectrogram based features, wavelet based features, mel-frequency cepstrum coefficients, and power burst curve features. Support vector machine is employed as the classifier. Performance of the respective fall detectors is investigated using real data obtained with the same radar operating resources and under identical sensing conditions. For the considered data, the spectrogram based feature set is shown to provide superior fall detection performance.

  17. Martian Dust Devil Movie, Phoenix Sol 104

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Surface Stereo Imager on NASA's Phoenix Mars Lander caught this dust devil in action west of the lander in four frames shot about 50 seconds apart from each other between 11:53 a.m. and 11:56 a.m. local Mars time on Sol 104, or the 104th Martian day of the mission, Sept. 9, 2008.

    Dust devils have not been detected in any Phoenix images from earlier in the mission, but at least six were observed in a dozen images taken on Sol 104.

    Dust devils are whirlwinds that often occur when the Sun heats the surface of Mars, or some areas on Earth. The warmed surface heats the layer of atmosphere closest to it, and the warm air rises in a whirling motion, stirring dust up from the surface like a miniature tornado.

    The dust devil visible in this sequence was about 1,000 meters (about 3,300 feet) from the lander when the first frame was taken, and had moved to about 1,700 meters (about 5,600 feet) away by the time the last frame was taken about two and a half minutes later. The dust devil was moving westward at an estimated speed of 5 meters per second (11 miles per hour), which is similar to typical late-morning wind speed and direction indicated by the telltale wind gauge on Phoenix.

    This dust devil is about 5 meters (16 feet) in diameter. This is much smaller than dust devils that have been observed by NASA's Mars Exploration Rover Spirit much closer to the equator. It is closer in size to dust devils seen from orbit in the Phoenix landing region, though still smaller than those..

    The image has been enhanced to make the dust devil easier to see. Some of the frame-to-frame differences in the appearance of foreground rocks is because each frame was taken through a different color filter.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  18. [RESULTS OF DUST FACTOR IN COPPER PYROMETALLURGY].

    PubMed

    Adrianovskiy, V I; Lipatov, G Ya; Zebzeeva, N V; Kuzmina, E A

    2016-01-01

    The dust entering the air of the working zone of metallurgical shops was shown to be presented by a disintegration aerosols originating in crushing and transporting ore materials and condensation occurring in the course of smelting, converting and fire-refining copper. The overwhelming majority of the grains have a size of 2.1-5.0 mm, which determines a fixed condition of the presence of given dust in the working area, its long presence in the deeper parts of the respiratory system. At the preparatory stages in the composition of the dust there are presented significant amounts of crystalline silicon dioxide possessing of the fibrogenic impact on the body. In the dust the presence of the crystalline silicon dioxide, arsenic, nickel, cadmium determines its carcinogenic hazard. The elevated dustiness of the air is noted with the reflective and especially mine melting, due to the imperfection of the technological equipment and sanitary technical devices. Autogenous smelting processes have demonstrated their hygienic advantage over outdated methods of producing blister copper mining and smelting reflectivity. PMID:27430065

  19. Coupling the Mars Dust and Water Cycles: Investigating the Role of Clouds in Controlling the Vertical Distribution of Dust During N. H. Summer

    NASA Technical Reports Server (NTRS)

    Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Wilson, R. J.

    2014-01-01

    The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere (Gierasch and Goody, 1968; Haberle et al., 1982; Zurek et al., 1992). Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer (Smith, 2004). Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across (Cantor et al., 2001). During some years, regional storms combine to produce hemispheric or planet encircling dust clouds that obscure the surface and raise atmospheric temperatures by as much as 40 K (Smith et al., 2002). Key recent observations of the vertical distribution of dust indicate that elevated layers of dust exist in the tropics and sub-tropics throughout much of the year (Heavens et al., 2011). These observations have brought particular focus on the processes that control the vertical distribution of dust in the Martian atmosphere. The goal of this work is to further our understanding of how clouds in particular control the vertical distribution of dust, particularly during N. H. spring and summer

  20. Dust in circumstellar disks

    NASA Astrophysics Data System (ADS)

    Rodmann, Jens

    2006-02-01

    This thesis presents observational and theoretical studies of the size and spatial distribution of dust particles in circumstellar disks. Using millimetre interferometric observations of optically thick disks around T Tauri stars, I provide conclusive evidence for the presence of millimetre- to centimetre-sized dust aggregates. These findings demonstrate that dust grain growth to pebble-sized dust particles is completed within less than 1 Myr in the outer disks around low-mass pre-main-sequence stars. The modelling of the infrared spectral energy distributions of several solar-type main-sequence stars and their associated circumstellar debris disks reveals the ubiquity of inner gaps devoid of substantial amounts of dust among Vega-type infrared excess sources. It is argued that the absence of circumstellar material in the inner disks is most likely the result of the gravitational influence of a large planet and/or a lack of dust-producing minor bodies in the dust-free region. Finally, I describe a numerical model to simulate the dynamical evolution of dust particles in debris disks, taking into account the gravitational perturbations by planets, photon radiation pressure, and dissipative drag forces due to the Poynting-Robertson effect and stellar wind. The validity of the code it established by several tests and comparison to semi-analytic approximations. The debris disk model is applied to simulate the main structural features of a ring of circumstellar material around the main-sequence star HD 181327. The best agreement between model and observation is achieved for dust grains a few tens of microns in size locked in the 1:1 resonance with a Jupiter-mass planet (or above) on a circular orbit.

  1. Analysis of dust cloud combustion using FAST Infrared Imaging

    NASA Astrophysics Data System (ADS)

    Marcotte, Frederick; Farley, Vincent; Savary, Simon

    2013-05-01

    Dust cloud combustion is unfortunately at risk in many working environments, jeopardizing several workers. The heat and shock waves resulting from the flame propagation into the dust cloud are harmful and lead to major endangerment or casualties. More precisely, dust cloud (small particles) explosions are even more malicious since they often result from ordinary materials such as coal, flour or pollen. Also, many metal powdered (such as aluminum oxide and magnesium) can form dangerous dust cloud when they are in suspensions in air. The understanding of this particular type of combustion is critical for the preventive care of sites and workers afflicted to such conditions. This paper presents the results of a dynamic flow analysis of metal particles combustion in a dust cloud. The ignition points, the flow rate as well as the propagation direction of the flow have been characterized using fast infrared imagery.

  2. Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover

    SciTech Connect

    Sobrado, J. M. Martín-Soler, J.; Martín-Gago, J. A.

    2015-10-15

    We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration.

  3. Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover.

    PubMed

    Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

    2015-10-01

    We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration. PMID:26520990

  4. Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover

    NASA Astrophysics Data System (ADS)

    Sobrado, J. M.; Martín-Soler, J.; Martín-Gago, J. A.

    2015-10-01

    We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration.

  5. Size-resolved dust flux measurements in a fallow wheat field from the Japan-Australia Dust Experiment (JADE)

    NASA Astrophysics Data System (ADS)

    Ishizuka, Masahide; Mikami, Masao; Leys, John F.; Shao, Yaping; Yamada, Yutaka; Heidenreich, Stephan

    2013-04-01

    The time- and size-resolved dust flux was observed by using optical particle counters and profile measurements of wind speed and air temperature on a dry, non-crusted fallow wheat field in Australia during the Japan-Australia Dust Experiment (JADE). Mineral dust emitted from the ground surface into the atmosphere by strong winds is transported around the globe and can have effects on cloud properties and thus on climate. Therefore not only on the amount of dust but also on the size of the dust particles is important. To evaluate the power n of the law linking dust flux to friction velocity according to the particle size, the time- and size-resolved number and mass concentrations were measured and dust flux along with the friction velocity was evaluated by a gradient method. This observation shows the simple relationship between diffusion dust flux and friction velocity using power law to address questions: what is the best value to use for the power n? Does the n has the particle size dependency? The dust concentration and dust flux fluctuated greatly with time, and the fluctuations corresponded well with fluctuations in u*. The trend of the relationship between friction velocity and dust flux was similar across all measured particle sizes. Size distributions of suspended dust particles at two different heights (1 and 3.5 m) had a similar shape and modal behavior. This is different from saltation sand particles. This result indicates that dust particles were transported by vertical turbulent eddy motions. As for dust mass flux, particles ranging in size from 2.0 to 8.4 μm composed 90% and particles from 0.6 to 2.0 μm composed 10%. While, finer dusts are dominant for number concentration. Number concentration and mass flux behave differently. The dust flux integrated from 0.6 to 8.4 μm in six bins fluctuated greatly, depending on friction velocity. When the power law equation was fitted to the data for each particle size range, the power n should be determined

  6. Dust control for Enabler

    NASA Technical Reports Server (NTRS)

    Hilton, Kevin; Karl, Chad; Litherland, Mark; Ritchie, David; Sun, Nancy

    1992-01-01

    The dust control group designed a system to restrict dust that is disturbed by the Enabler during its operation from interfering with astronaut or camera visibility. This design also considers the many different wheel positions made possible through the use of artinuation joints that provide the steering and wheel pitching for the Enabler. The system uses a combination of brushes and fenders to restrict the dust when the vehicle is moving in either direction and in a turn. This design also allows for each of maintenance as well as accessibility of the remainder of the vehicle.

  7. Dust control for Enabler

    NASA Technical Reports Server (NTRS)

    Hilton, Kevin; Karl, Chad; Litherland, Mark; Ritchie, David; Sun, Nancy

    1992-01-01

    The dust control group designed a system to restrict dust that is disturbed by the Enabler during its operation from interfering with astronaut or camera visibility. This design also considers the many different wheel positions made possible through the use of artinuation joints that provide the steering and wheel pitching for the Enabler. The system uses a combination of brushes and fenders to restrict the dust when the vehicle is moving in either direction and in a turn. This design also allows for ease of maintenance as well as accessibility of the remainder of the vehicle.

  8. Dust torus around Mars

    NASA Technical Reports Server (NTRS)

    Juhasz, Antal; Horanyi, Mihaly

    1995-01-01

    We investigate the orbital dynamics of small dust particles generated via the continuous micrometeoroid bombardment of the Martian moons. In addition to Mar's oblateness, we also consider the radiation pressure perturbation that is complicated by the planet's eccentric orbit and tilted rotational axis. Considering the production rates and the lifetimes of dust grains, we show that particles from Deimos with radii of about 15 micrometers are expected to dominate the population of a permanently present and tilted dust torus. This torus has an estimated peak number density of approximately equals 5 x 10(exp -12)/cu cm and an optical depth of approximately equals 4 x 10(exp -8).

  9. Dust in the Mediterranean

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On July 24, the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), acquired this true-color image of a large cloud of dust blowing from northern Africa across the Mediterranean Sea. The dust storm has persisted in the region for at least a week. In this image, the brownish dust plume appears to originate about 260 miles (400 km) east of Algiers, Algeria, and is blowing toward the northwest coast of Sardinia, Italy. SeaWiFS flies aboard the OrbView-2 Satellite. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center and ORBIMAGE

  10. Electrostatic dust detector

    DOEpatents

    Skinner, Charles H.

    2006-05-02

    An apparatus for detecting dust in a variety of environments which can include radioactive and other hostile environments both in a vacuum and in a pressurized system. The apparatus consists of a grid coupled to a selected bias voltage. The signal generated when dust impacts and shorts out the grid is electrically filtered, and then analyzed by a signal analyzer which is then sent to a counter. For fine grids a correlation can be developed to relate the number of counts observed to the amount of dust which impacts the grid.

  11. Characterization of aerosolized bacteria and fungi from desert dust events in Mali, West Africa

    USGS Publications Warehouse

    Kellogg, C.A.; Griffin, Dale W.; Garrison, V.H.; Peak, K.K.; Royall, N.; Smith, R.R.; Shinn, E.A.

    2004-01-01

    Millions of metric tons of African desert dust blow across the Atlantic Ocean each year, blanketing the Caribbean and southeastern United States. Previous work in the Caribbean has shown that atmospheric samples collected during dust events contain living microbes, including plant and opportunistic human pathogens. To better understand the potential downwind public health and ecosystem effects of the dust microbes, it is important to characterize the source population. We describe 19 genera of bacteria and 3 genera of fungi isolated from air samples collected in Mali, a known source region for dust storms, and over which large dust storms travel.

  12. Exercises to help prevent falls

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000493.htm Exercises to help prevent falls To use the sharing ... and easily. Do not hold your breath. Balance exercises You can do some balance exercises during everyday ...

  13. Highlights of 2012 Fall Meeting

    NASA Astrophysics Data System (ADS)

    Finn, Carol

    2013-01-01

    This past December the streets of San Francisco, Calif., surrounding the Moscone Center were awash with a sea of Earth and space scientists attending the 45th consecutive AGU Fall Meeting, eager to share and expand their knowledge "for the benefit of humanity." As it has for many years, attendance at AGU's Fall Meeting—the largest gathering of Earth and space scientists in the world—continued to increase, this year passing the 24,000 mark. Attendees at the meeting, which took place on 3-7 December 2012, hailed from 97 countries; nearly 7000 of them were students. News from the Fall Meeting was carried in newspapers and on Web sites around the world, and the social media sphere lit up with talk of AGU and the Fall Meeting. It's even reported that for a short time we were a trending topic on Twitter.

  14. Community College Estimated Growth: Fall 2010

    ERIC Educational Resources Information Center

    Phillippe, Kent; Mullin, Christopher M.

    2011-01-01

    A survey from the American Association of Community Colleges (AACC) found that enrollment growth in fall 2010 slowed its pace at community colleges, increasing 3.2% from the previous year. This contrasts with more dramatic increases in recent years: more than 11% between fall 2008 and fall 2009, and nearly 17% between fall 2007 and fall 2009,…

  15. The Sky is Falling: An air deposition/stormwater runoff model simulating the pathways of five heavy metals from their status as mobile and stack exhaust constituents to their delivery to the Elizabeth River

    SciTech Connect

    Barrett-McDaniels, J.; Barrett, M.

    1997-12-31

    Recent studies by the Environmental Protection Agency (EPA) indicate that air emissions contribute a major portion of the total loading of toxic metals to the waters of the Chesapeake Bay and its tributaries. According to the Chesapeake Executive Council of the interstate Chesapeake Bay Program, five of these metals, cadmium, chromium, copper, lead, and zinc, have been observed to have a negative impact on the waters of the Elizabeth River, which is within the Chesapeake Bay watershed. In order to better define the sources and processes which contribute to concentrations of these metals in the Elizabeth River, this analysis simulates the pathway of these metals from their status as mobile and stack exhaust constituents to their delivery to the river. EPA`s ISCST3 model was used to predict deposition loading on the Elizabeth River water and watershed surfaces, using regional annual meteorological data. Air emissions input to the ISCST3 model were derived from stationary and mobile sources: stationary source emissions were estimated using Virginia Department of Environmental Quality inventories and EPA-approved emissions factors for major sources with the potential to impact the watershed, while mobile source emissions were estimated using traffic volumes provided by the Department of Transportation and EPA-approved emissions factors. EPA`s SWMM model was then used to predict maximum short term and average annual build up and wash off rates for these metals using recorded rainfall data and existing land use and impervious cover for the watershed. The results are compared to water quality monitoring data from the municipal NPDES stormwater wet weather monitoring permit program.

  16. Molecular mechanisms of dust-induced toxicity in human corneal epithelial cells: Water and organic extract of office and house dust.

    PubMed

    Xiang, Ping; Liu, Rong-Yan; Sun, Hong-Jie; Han, Yong-He; He, Rui-Wen; Cui, Xin-Yi; Ma, Lena Q

    2016-01-01

    Human corneal epithelial (HCE) cells are continually exposed to dust in the air, which may cause corneal epithelium damage. Both water and organic soluble contaminants in dust may contribute to cytotoxicity in HCE cells, however, the associated toxicity mechanisms are not fully elucidated. In this study, indoor dust from residential houses and commercial offices in Nanjing, China was collected and the effects of organic and water soluble fraction of dust on primary HCE cells were examined. The concentrations of heavy metals in the dust and dust extracts were determined by ICP-MS and PAHs by GC-MS, with office dust having greater concentrations of heavy metals and PAHs than house dust. Based on LC50, organic extract was more toxic than water extract, and office dust was more toxic than house dust. Accordingly, the organic extracts induced more ROS, malondialdehyde, and 8-Hydroxydeoxyguanosine and higher expression of inflammatory mediators (IL-1β, IL-6, and IL-8), and AhR inducible genes (CYP1A1, and CYP1B1) than water extracts (p<0.05). Extracts of office dust presented greater suppression of superoxide dismutase and catalase activity than those of house dust. In addition, exposure to dust extracts activated NF-κB signal pathway except water extract of house dust. The results suggested that both water and organic soluble fractions of dust caused cytotoxicity, oxidative damage, inflammatory response, and activation of AhR inducible genes, with organic extracts having higher potential to induce adverse effects on primary HCE cells. The results based on primary HCE cells demonstrated the importance of reducing contaminants in indoor dust to reduce their adverse impacts on human eyes. PMID:27131017

  17. The influence of absorbed solar radiation by Saharan dust on hurricane genesis

    NASA Astrophysics Data System (ADS)

    Bretl, Sebastian; Reutter, Philipp; Raible, Christoph C.; Ferrachat, Sylvaine; Poberaj, Christina Schnadt; Revell, Laura E.; Lohmann, Ulrike

    2015-03-01

    To date, the radiative impact of dust and the Saharan air layer (SAL) on North Atlantic hurricane activity is not yet known. According to previous studies, dust stabilizes the atmosphere due to absorption of solar radiation but thus shifts convection to regions more conducive for hurricane genesis. Here we analyze differences in hurricane genesis and frequency from ensemble sensitivity simulations with radiatively active and inactive dust in the aerosol-climate model ECHAM6-HAM. We investigate dust burden and other hurricane-related variables and determine their influence on disturbances which develop into hurricanes (developing disturbances, DDs) and those which do not (nondeveloping disturbances, NDDs). Dust and the SAL are found to potentially have both inhibiting and supporting influences on background conditions for hurricane genesis. A slight southward shift of DDs is determined when dust is active as well as a significant warming of the SAL, which leads to a strengthening of the vertical circulation associated with the SAL. The dust burden of DDs is smaller in active dust simulations compared to DDs in simulations with inactive dust, while NDDs contain more dust in active dust simulations. However, no significant influence of radiatively active dust on other variables in DDs and NDDs is found. Furthermore, no substantial change in the DD and NDD frequency due to the radiative effects of dust can be detected.

  18. 2. Credit BG. View down dust ditch at northeast side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Credit BG. View down dust ditch at northeast side of A Street, looking north northwest in "the loop". Note culverts used to give vehicular and pedestrian access to buildings northeast of A Street, some foundations of which may be seen at right of view. Structures in background belong to Jet Propulsion Laboratory Edwards Facility. - Edwards Air Force Base, North Base, Dust Ditch System, Traversing North Base, Boron, Kern County, CA

  19. Comparison of Contributions of Wind-blown and Anthropogenic Fugitive Dust Particles to Atmospheric Particulate Matter

    NASA Astrophysics Data System (ADS)

    Park, S.; Gong, S.

    2010-12-01

    A new wind-blown-dust emissions module was recently implemented into AURAMS, a Canadian regional air quality model (Park et al., 2009; Park et al., 2007), to investigate the relative impact of wind-blown dust vs. anthropogenic fugitive dust on air quality in North America. In order to apply the wind-blown dust emissions module to the entire North American continent, a soil-grain-size-distribution map was developed using the outputs of four monthly runs of AURAMS for 2002 and available PM2.5 dust-content observations. The simulation results using the new soil-grain-size-distribution map showed that inclusion of wind-blown dust emissions is essential to predict the impact of dust aerosols on air quality in North America, especially in the western U.S.. The wind-blown dust emissions varied widely by season, whereas the anthropogenic fugitive dust emissions did not change significantly. In the spring (April), the continental monthly average emissions rate of wind-blown dust was much higher than that of anthropogenic fugitive dust. The total amount of wind-blown dust emissions in North America predicted by the model for 2002 was comparable to that of anthropogenic fugitive dust emissions. Even with the inclusion of wind-blown dust emissions, however, the model still had difficulty simulating dust concentrations. Further improvements are needed, in terms of both limitations of the wind-blown-dust emission module and uncertainties in the anthropogenic fugitive dust emissions inventories, for improved dust modelling. References Park, S.H., S.L. Gong, W. Gong, P.A. Makar, M.D. Moran, C.A. Stroud, and J. Zhang, Sensitivity of surface characteristics on the simulation of wind-blown dust source in North America, Atmospheric Environment, 43 (19), 3122-3129, 2009. Park, S.H., S.L. Gong, T.L. Zhao, R.J. Vet, V.S. Bouchet, W. Gong, P.A. Makar, M.D. Moran, C. Stroud, and J. Zhang, Simulation of entrainment and transport of dust particles within North America in April 2001 ("Red

  20. Air ejector augmented compressed air energy storage system

    DOEpatents

    Ahrens, Frederick W.; Kartsounes, George T.

    1980-01-01

    Energy is stored in slack demand periods by charging a plurality of underground reservoirs with air to the same peak storage pressure, during peak demand periods throttling the air from one storage reservoir into a gas turbine system at a constant inlet pressure until the air pressure in the reservoir falls to said constant inlet pressure, thereupon permitting air in a second reservoir to flow into said gas turbine system while drawing air from the first reservoir through a variable geometry air ejector and adjusting said variable geometry air ejector, said air flow being essentially at the constant inlet pressure of the gas turbine system.

  1. Air ejector augmented compressed air energy storage system

    DOEpatents

    Ahrens, F.W.; Kartsounes, G.T.

    Energy is stored in slack demand periods by charging a plurality of underground reservoirs with air to the same peak storage pressure, during peak demand periods throttling the air from one storage reservoir into a gas turbine system at a constant inlet pressure until the air presure in the reservoir falls to said constant inlet pressure, thereupon permitting air in a second reservoir to flow into said gas turbine system while drawing air from the first reservoir through a variable geometry air ejector and adjusting said variable geometry air ejector, said air flow being essentially at the constant inlet pressure of the gas turbine system.

  2. Dust mite (image)

    MedlinePlus

    This is a magnified photograph of a dust mite. Mites are carriers (vectors) of many important diseases including typhus (scrub and murine) and rickettsialpox. (Image courtesy of the Centers for Disease ...

  3. Dusts and Molds

    MedlinePlus

    ... of dust can result in sensitization. Symptoms include chills, fever, cough, chest congestion, fatigue, and shortness of ... grain and forage products. Symptoms include cough, fever, chills, body aches, and fatigue. These symptoms appear from ...

  4. 1983 Transatlantic Dust Event

    NASA Video Gallery

    This visualization (prepared in 2001) shows dust being blown westward over the Atlantic from northern Africa in early 1983, from aerosol measurements taken by Nimbus 7's TOMS instrument. Saharan du...

  5. Adhesion of Lunar Dust

    NASA Astrophysics Data System (ADS)

    Walton, Otis R.

    2007-04-01

    This paper reviews the physical characteristics of lunar dust and the effects of various fundamental forces acting on dust particles on surfaces in a lunar environment. There are transport forces and adhesion forces after contact. Mechanical forces (i.e., from rover wheels, astronaut boots and rocket engine blast) and static electric effects (from UV photo-ionization and/or tribo-electric charging) are likely to be the major contributors to the transport of dust particles. If fine regolith particles are deposited on a surface, then surface energy-related (e.g., van der Walls) adhesion forces and static-electric-image forces are likely to be the strongest contributors to adhesion. Some measurement techniques are offered to quantify the strength of adhesion forces. And finally some dust removal techniques are discussed.

  6. The Lunar Dust Pendulum

    NASA Technical Reports Server (NTRS)

    Collier, Michael R.; Stubbs, Timothy J.; Farrell, William M.

    2011-01-01

    Shadowed regions on the lunar surface acquire a negative potential. In particular, shadowed craters can have a negative potential with respect to the surrounding lunar regolith in sunlight, especially near the terminator regions. Here we analyze the motion of a positively charged lunar dust grain in the presence of a shadowed crater at a negative potential in vacuum. Previous models describing the transport of charged lunar dust close to the surface have typically been limited to one-dimensional motion in the vertical direction, e.g. electrostatic levitation; however, the electric fields in the vicinity of shadowed craters will also have significant components in the horizontal directions. We propose a model that includes both the horizontal and vertical motion of charged dust grains near shadowed craters. We show that the dust grains execute oscillatory trajectories and present an expression for the period of oscillation drawing an analogy to the motion of a pendulum.

  7. The Lunar Dust Pendulum

    NASA Technical Reports Server (NTRS)

    Kuntz, Kip; Collier, Michael R.; Stubbs, Timothy J.; Farrell, William M.

    2011-01-01

    Shadowed regions on the lunar surface acquire a negative potential. In particular, shadowed craters can have a negative potential with respect to the surrounding lunar regolith in sunlight, especially near the terminator regions. Here we analyze the motion of a positively charged lnnar dust grain in the presence of a shadowed crater at a negative potential in vacuum. Previous models describing the transport of charged lunar dust close to the surface have typically been limited to one-dimensional motion in the vertical direction, e.g. electrostatic levitation; however. the electric fields in the vicinity of shadowed craters will also have significant components in the horizontal directions. We propose a model that includes both the horizontal and vertical motion of charged dust grains near shadowed craters. We show that the dust grains execute oscillatory trajectories and present an expression for the period of oscillation drawing an analogy to the motion of a pendulum.

  8. Adhesion of Lunar Dust

    NASA Technical Reports Server (NTRS)

    Walton, Otis R.

    2007-01-01

    This paper reviews the physical characteristics of lunar dust and the effects of various fundamental forces acting on dust particles on surfaces in a lunar environment. There are transport forces and adhesion forces after contact. Mechanical forces (i.e., from rover wheels, astronaut boots and rocket engine blast) and static electric effects (from UV photo-ionization and/or tribo-electric charging) are likely to be the major contributors to the transport of dust particles. If fine regolith particles are deposited on a surface, then surface energy-related (e.g., van der Walls) adhesion forces and static-electric-image forces are likely to be the strongest contributors to adhesion. Some measurement techniques are offered to quantify the strength of adhesion forces. And finally some dust removal techniques are discussed.

  9. Dust and Smoke

    Atmospheric Science Data Center

    2014-05-15

    ... dust, the most common non-spherical aerosol type, from pollution and forest fire particles. Determining aerosol characteristics is a ... higher, indicating the relative abundance of small pollution particles, especially over the Atlantic where the aerosol optical ...

  10. Reducing dust emissions at OAO Alchevskkoks coke battery 10A

    SciTech Connect

    T.F. Trembach; E.N. Lanina

    2009-07-15

    Coke battery 10A with rammed batch is under construction at OAO Alchevskkoks. The design documentation developed by Giprokoks includes measures for reducing dust emissions to the atmosphere. Aspiration systems with dry dust trapping are employed in the new components of coke battery 10A and in the existing coke-sorting equipment. Two-stage purification of dusty air in cyclones and bag filters is employed for the coke-sorting equipment. This system considerably reduces coke-dust emissions to the atmosphere.

  11. The Galileo dust detector

    NASA Technical Reports Server (NTRS)

    Gruen, E.; Fechtig, H.; Hanner, M. S.; Kissel, J.; Lindblad, B. A.; Linkert, D.; Maas, D.; Morfill, G. E.; Zook, H. A.

    1990-01-01

    The Galileo Dust Detector is intended to provide direct observations of dust grains with masses between 10(sup -19) kg and 10(sup -9) kg in interplanetary space and in the Jovian system, to investigate their physical and dynamical properties as functions of the distances to the Sun, to Jupiter and to its satellites, to study its interaction with the Galilean satellites and the Jovian magnetosphere. Surface phenomena of the satellites (like albedo variations), which might be effects of meteoroid impacts will be compared with the dust environment. Electric charges of particulate matter in the magnetosphere and its consequences will be studied; e.g. the effects of the magnetic field on the trajectories of dust particles and fragmentation of particles due to electrostatic disruption. The investigation is performed with an instrument that measures the mass, speed, flight direction and electric charge of individual dust particles. It is a multi-coincidence detector with a mass sensitivity 10(sup 6) times higher than that of previous in-situ experiments which measured dust in the outer solar system. The instrument weighs 4.2 kg, consumes 2.4 W, and has a normal data transmission rate of 24 bits/s in nominal spacecraft tracking mode. On December 29, 1989 the instrument was switched-on. After the instrument had been configured to flight conditions cruise science data collection started immediately. In the period to May 18, 1990 at least 168 dust impacts have been recorded. For 81 of these dust grains, masses and impact speeds have been determined. First flux values are also given.

  12. 42 CFR 84.1158 - Dust, fume, and mist tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Respirator types Pressure tightness test 1 Isoamyl acetate test 84.1141 84.1142 Dusts: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Fumes: Air Contamination Level not less than 0.05 mg/M3 X X Mists: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Dusts, Fumes, and Mists:...

  13. 42 CFR 84.1158 - Dust, fume, and mist tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Respirator types Pressure tightness test 1 Isoamyl acetate test 84.1141 84.1142 Dusts: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Fumes: Air Contamination Level not less than 0.05 mg/M3 X X Mists: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Dusts, Fumes, and Mists:...

  14. 42 CFR 84.1158 - Dust, fume, and mist tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Respirator types Pressure tightness test 1 Isoamyl acetate test 84.1141 84.1142 Dusts: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Fumes: Air Contamination Level not less than 0.05 mg/M3 X X Mists: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Dusts, Fumes, and Mists:...

  15. 42 CFR 84.1158 - Dust, fume, and mist tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Respirator types Pressure tightness test 1 Isoamyl acetate test 84.1141 84.1142 Dusts: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Fumes: Air Contamination Level not less than 0.05 mg/M3 X X Mists: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Dusts, Fumes, and Mists:...

  16. 42 CFR 84.1158 - Dust, fume, and mist tests; respirators with filters; minimum requirements; general.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Respirator types Pressure tightness test 1 Isoamyl acetate test 84.1141 84.1142 Dusts: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Fumes: Air Contamination Level not less than 0.05 mg/M3 X X Mists: Air Contamination Level not less than 0.05 mg/M3 or 2 mppcf X Dusts, Fumes, and Mists:...

  17. Barometric pressure and triaxial accelerometry-based falls event detection.

    PubMed

    Bianchi, Federico; Redmond, Stephen J; Narayanan, Michael R; Cerutti, Sergio; Lovell, Nigel H

    2010-12-01

    Falls and fall related injuries are a significant cause of morbidity, disability, and health care utilization, particularly among the age group of 65 years and over. The ability to detect falls events in an unsupervised manner would lead to improved prognoses for falls victims. Several wearable accelerometry and gyroscope-based falls detection devices have been described in the literature; however, they all suffer from unacceptable false positive rates. This paper investigates the augmentation of such systems with a barometric pressure sensor, as a surrogate measure of altitude, to assist in discriminating real fall events from normal activities of daily living. The acceleration and air pressure data are recorded using a wearable device attached to the subject's waist and analyzed offline. The study incorporates several protocols including simulated falls onto a mattress and simulated activities of daily living, in a cohort of 20 young healthy volunteers (12 male and 8 female; age: 23.7 ±3.0 years). A heuristically trained decision tree classifier is used to label suspected falls. The proposed system demonstrated considerable improvements in comparison to an existing accelerometry-based technique; showing an accuracy, sensitivity and specificity of 96.9%, 97.5%, and 96.5%, respectively, in the indoor environment, with no false positives generated during extended testing during activities of daily living. This is compared to 85.3%, 75%, and 91.5% for the same measures, respectively, when using accelerometry alone. The increased specificity of this system may enhance the usage of falls detectors among the elderly population. PMID:20805056

  18. Dust coatings on basaltic rocks and implications for thermal infrared spectroscopy of Mars

    USGS Publications Warehouse

    Johnson, J. R.; Christensen, P.R.; Lucey, P.G.

    2002-01-01

    Thin coatings of atmospherically deposited dust can mask the spectral characteristics of underlying surfaces on Mars from the visible to thermal infrared wavelengths, making identification of substrate and coating mineralogy difficult from lander and orbiter spectrometer data. To study the spectral effects of dust coatings, we acquired thermal emission and hemispherical reflectance spectra (5-25 ??m; 2000-400 cm-1) of basaltic andesite coated with different thicknesses of air fall-deposited palagonitic soils, fine-grained ceramic clay powders, and terrestrial loess. The results show that thin coatings (10-20 ??m) reduce the spectral contrast of the rock substrate substantially, consistent with previous work. This contrast reduction continues linearly with increasing coating thickness until a "saturation thickness" is reached, after which little further change is observed. The saturation thickness of the spectrally flat palagonite coatings is ??? 100-120 ??m, whereas that for coatings with higher spectral contrast is only ??? 50-75 ??m. Spectral differences among coated and uncoated samples correlate with measured coating thicknesses in a quadratic manner, whereas correlations with estimated surface area coverage are better fit by linear functions. Linear mixture modeling of coated samples using the rock substrate and coating materials as end-members is also consistent with their measured coating thicknesses and areal coverage. A comparison of ratios of Thermal Emission Spectrometer (TES) spectra of dark and bright intracrater and windstreak deposits associated with Radau crater suggests that the dark windstreak material may be coated with as much as 90% areal coverage of palagonitic dust. The data presented here also will help improve interpretations of upcoming mini-TES and Thermal Emission Imaging System (THEMIS) observations of coated Mars surface materials.

  19. Fall prevention in the elderly

    PubMed Central

    Ungar, Andrea; Rafanelli, Martina; Iacomelli, Iacopo; Brunetti, Maria Angela; Ceccofiglio, Alice; Tesi, Francesca; Marchionni, Niccolò

    2013-01-01

    Summary Falls are frequent in the elderly and affect mortality, morbidity, loss of functional capacity and institutionalization. In the older patient the incidence of falls can sometimes be underestimated, even in the absence of a clear cognitive impairment, because it is often difficult to reconstruct the dynamics. It is quite common that forms due to syncope are associated with retrograde amnesia and in 40 to 60% of the cases falls happen in the absence of witnesses. The pathogenesis of falls is often multifactorial, due to physiological age-related changes or more properly pathological factors, or due to the environment. The identification of risk factors is essential in the planning of preventive measures. Syncope is one of major causes of falls. About 20% of cardiovascular syncope in patients older than 70 appears as a fall and more than 20% of older people with Carotid Sinus Syndrome complain of falls as well as syncope. These data clearly state that older patients with history of falls should undergo a cardiovascular and neuroautonomic assessment besides the survey of other risk factors. Multifactorial assessment requires a synergy of various specialists. The geriatrician coordinates the multidisciplinary intervention in order to make the most effective evaluation of the risk of falling, searching for all predisposing factors, aiming towards a program of prevention. In clear pathological conditions it is possible to enact a specific treatment. Particular attention must indeed be paid to the re-evaluation of drug therapy, with dose adjustments or withdrawal especially for antihypertensive, diuretics and benzodiazepines. The Guidelines of the American Geriatrics Society recommend modification of environmental hazards, training paths, hip protectors and appropriate use of support tools (sticks, walkers), which can be effective elements of a multifactorial intervention program. Balance exercises are also recommended. In conclusion, an initial assessment

  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.