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Sample records for air mass factor

  1. On the evaluation of air mass factors for atmospheric near-ultraviolet and visible absorption spectroscopy

    NASA Technical Reports Server (NTRS)

    Perliski, Lori M.; Solomon, Susan

    1993-01-01

    The interpretation of UV-visible twilight absorption measurements of atmospheric chemical constituents is dependent on how well the optical path, or air mass factor, of light collected by the spectrometer is understood. A simple single scattering model and a Monte Carlo radiative transfer scheme have been developed to study the effects of multiple scattering, aerosol scattering, surface albedo and refraction on air mass factors for scattered light observations. At fairly short visible wavelengths (less than about 450 nm), stratospheric air mass factors are found to be relatively insensitive to multiple scattering, surface albedo and refraction, as well as aerosol scattering by background aerosols. Longer wavelengths display greater sensitivity to refraction and aerosol scattering. Tropospheric air mass factors are found to be highly dependent on aerosol scattering, surface albedo and, at long visible wavelengths (about 650 nm), refraction. Absorption measurements of NO2 and O4 are shown to support these conclusions.

  2. Visual Steering and Verification of Mass Spectrometry Data Factorization in Air Quality Research.

    PubMed

    Engel, D; Greff, K; Garth, C; Bein, K; Wexler, A; Hamann, B; Hagen, H

    2012-12-01

    The study of aerosol composition for air quality research involves the analysis of high-dimensional single particle mass spectrometry data. We describe, apply, and evaluate a novel interactive visual framework for dimensionality reduction of such data. Our framework is based on non-negative matrix factorization with specifically defined regularization terms that aid in resolving mass spectrum ambiguity. Thereby, visualization assumes a key role in providing insight into and allowing to actively control a heretofore elusive data processing step, and thus enabling rapid analysis meaningful to domain scientists. In extending existing black box schemes, we explore design choices for visualizing, interacting with, and steering the factorization process to produce physically meaningful results. A domain-expert evaluation of our system performed by the air quality research experts involved in this effort has shown that our method and prototype admits the finding of unambiguous and physically correct lower-dimensional basis transformations of mass spectrometry data at significantly increased speed and a higher degree of ease.

  3. The influence of polarization on box air mass factors for UV/vis nadir satellite observations

    NASA Astrophysics Data System (ADS)

    Hilboll, Andreas; Richter, Andreas; Rozanov, Vladimir V.; Burrows, John P.

    2015-04-01

    Tropospheric abundances of pollutant trace gases like, e.g., NO2, are often derived by applying the differential optical absorption spectroscopy (DOAS) method to space-borne measurements of back-scattered and reflected solar radiation. The resulting quantity, the slant column density (SCD), subsequently has to be converted to more easily interpretable vertical column densities by means of the so-called box air mass factor (BAMF). The BAMF describes the ratio of SCD and VCD within one atmospheric layer and is calculated by a radiative transfer model. Current operational and scientific data products of satellite-derived trace gas VCDs do not include the effect of polarization in their radiative transfer models. However, the various scattering processes in the atmosphere do lead to a distinctive polarization pattern of the observed Earthshine spectra. This study investigates the influence of these polarization patterns on box air mass factors for satellite nadir DOAS measurements of NO2 in the UV/vis wavelength region. NO2 BAMFs have been simulated for a multitude of viewing geometries, surface albedos, and surface altitudes, using the radiative transfer model SCIATRAN. The results show a potentially large influence of polarization on the BAMF, which can reach 10% and more close to the surface. A simple correction for this effect seems not to be feasible, as it strongly depends on the specific measurement scenario and can lead to both high and low biases of the resulting NO2 VCD. We therefore conclude that all data products of NO2 VCDs derived from space-borne DOAS measurements should include polarization effects in their radiative transfer model calculations, or at least include the errors introduced by using linear models in their uncertainty estimates.

  4. Inverse Estimation of SO2 Emissions over China with Local Air Mass Factor Applied

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wang, J.; Xu, X.; Henze, D. K.

    2015-12-01

    Sulfur dioxide (SO2) has significant impacts on human health as it forms sulfate aerosols in the atmosphere. Widespread uncertainty in the magnitude of SO2 emissions hinders efforts to address this issue. In this work we use Ozone Monitoring Instrument (OMI) slant column SO2 observations as constraints to conduct inversion of SO2 emissions over China for April 2008. Local air mass factors are formulated as the integral of the relative vertical distribution of SO2 simulated from GEOS-Chem, weighted by scattering weights computed from VLIDORT. They are applied to convert slant column to vertical column GEOS-Chem SO2. After data assimilation SO2 emissions decrease in Sichuan Basin, South China, and most areas of North China. The posterior SO2 emissions are evaluated with in situ SO2 observation. Besides, we apply the posterior SO2 emissions of April 2008 to April 2009, and it leads to improved agreement of modeled SO2 to the OMI observations. This offers potential to update SO2 emissions in real time.

  5. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; Torres, O.; de Haan, J. F.

    2015-03-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. OMI observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2-O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD). Aerosols implicitly influence the tropospheric air mass factor (AMF) calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the tropospheric NO2 AMF calculation by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD) and single scattering albedo (SSA) retrieved by the OMI near-UV aerosol algorithm (OMAERUV) in the DISAMAR radiative transfer model for cloud-free scenes. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO) retrieval; the mean and standard deviation (SD) of the difference was 0.6 ± 8%. Averaged over three successive South American biomass burning seasons (2006-2008), the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 72% of the daily OMAERUV AOD observations were within 0.3 of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10% higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30%, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and explicit aerosol parameters is on average 6 and 3

  6. Structural uncertainty in air mass factor calculation for NO2 and HCHO satellite retrievals

    NASA Astrophysics Data System (ADS)

    Lorente, Alba; Folkert Boersma, K.; Yu, Huan; Dörner, Steffen; Hilboll, Andreas; Richter, Andreas; Liu, Mengyao; Lamsal, Lok N.; Barkley, Michael; De Smedt, Isabelle; Van Roozendael, Michel; Wang, Yang; Wagner, Thomas; Beirle, Steffen; Lin, Jin-Tai; Krotkov, Nickolay; Stammes, Piet; Wang, Ping; Eskes, Henk J.; Krol, Maarten

    2017-03-01

    Air mass factor (AMF) calculation is the largest source of uncertainty in NO2 and HCHO satellite retrievals in situations with enhanced trace gas concentrations in the lower troposphere. Structural uncertainty arises when different retrieval methodologies are applied within the scientific community to the same satellite observations. Here, we address the issue of AMF structural uncertainty via a detailed comparison of AMF calculation methods that are structurally different between seven retrieval groups for measurements from the Ozone Monitoring Instrument (OMI). We estimate the escalation of structural uncertainty in every sub-step of the AMF calculation process. This goes beyond the algorithm uncertainty estimates provided in state-of-the-art retrievals, which address the theoretical propagation of uncertainties for one particular retrieval algorithm only. We find that top-of-atmosphere reflectances simulated by four radiative transfer models (RTMs) (DAK, McArtim, SCIATRAN and VLIDORT) agree within 1.5 %. We find that different retrieval groups agree well in the calculations of altitude resolved AMFs from different RTMs (to within 3 %), and in the tropospheric AMFs (to within 6 %) as long as identical ancillary data (surface albedo, terrain height, cloud parameters and trace gas profile) and cloud and aerosol correction procedures are being used. Structural uncertainty increases sharply when retrieval groups use their preference for ancillary data, cloud and aerosol correction. On average, we estimate the AMF structural uncertainty to be 42 % over polluted regions and 31 % over unpolluted regions, mostly driven by substantial differences in the a priori trace gas profiles, surface albedo and cloud parameters. Sensitivity studies for one particular algorithm indicate that different cloud correction approaches result in substantial AMF differences in polluted conditions (5 to 40 % depending on cloud fraction and cloud pressure, and 11 % on average) even for low

  7. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; Torres, O.; de Haan, J. F.

    2015-09-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. Satellite observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2-O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD). Aerosols implicitly influence the tropospheric air mass factor (AMF) calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the Ozone Monitoring Instrument (OMI) tropospheric NO2 AMF calculation for cloud-free scenes. We do so by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD) and single scattering albedo (SSA) retrieved by the OMI near-UV aerosol algorithm (OMAERUV) in the DISAMAR radiative transfer model. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO) retrieval; the mean and standard deviation of the difference was 0.6 ± 8 %. Averaged over three successive South American biomass burning seasons (2006-2008), the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 68 % of the daily OMAERUV AOD observations were within 30 % of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10 % higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30 %, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and

  8. Differential optical absorption spectroscopy (DOAS) and air mass factor concept for a multiply scattering vertically inhomogeneous medium: theoretical consideration

    NASA Astrophysics Data System (ADS)

    Rozanov, V. V.; Rozanov, A. V.

    2010-06-01

    The Differential Optical Absorption Spectroscopy (DOAS) technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering. Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS), the modified (MDOAS), and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption. The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as well as of the relationship between

  9. Differential optical absorption spectroscopy (DOAS) and air mass factor concept for a multiply scattering vertically inhomogeneous medium: theoretical consideration

    NASA Astrophysics Data System (ADS)

    Rozanov, V. V.; Rozanov, A. V.

    2010-02-01

    The Differential Optical Absorption Spectroscopy (DOAS) technique is widely used to retrieve amounts of atmospheric species from measurements of the direct solar light transmitted through the Earth's atmosphere as well as of the solar light scattered in the atmosphere or reflected from the Earth's surface. For the transmitted direct solar light the theoretical basis of the DOAS technique represented by the Beer-Lambert law is well studied. In contrast, scarcely investigated is the theoretical basis and validity range of the DOAS method for those cases where the contribution of the multiple scattering processes is not negligible. Our study is intended to fill this gap by means of a theoretical investigation of the applicability of the DOAS technique for the retrieval of amounts of atmospheric species from observations of the scattered solar light with a non-negligible contribution of the multiple scattering. Starting from the expansion of the intensity logarithm in the functional Taylor series we formulate the general form of the DOAS equation. The thereby introduced variational derivative of the intensity logarithm with respect to the variation of the gaseous absorption coefficient, which is often referred to as the weighting function, is demonstrated to be closely related to the air mass factor. Employing some approximations we show that the general DOAS equation can be rewritten in the form of the weighting function (WFDOAS), the modified (MDOAS), and the standard DOAS equations. For each of these forms a specific equation for the air mass factor follows which, in general, is not suitable for other forms of the DOAS equation. Furthermore, the validity range of the standard DOAS equation is quantitatively investigated using a suggested criterion of a weak absorption. The results presented in this study are intended to provide a basis for a better understanding of the applicability range of different forms of the DOAS equation as well as of the relationship between

  10. Graphical mass factorization

    NASA Astrophysics Data System (ADS)

    Humpert, B.; van Neerven, W. L.

    1981-07-01

    We point to the close analogy between (multiplicative) BPHZ-renormalization and mass factorization. Adapation of the forest formula to mass singular graphs allows an alternative proof of mass factorization. A diagrammatic method is developed to carry out diagram-by-diagram mass factorization with the mass singularities being subtracted by counter terms which built up the operator matrix element. The reasoning is exposed for deep-inelastic (DI) scattering and for the Drell-Yan (DY) process.

  11. Retrieval of vertical columns of sulfur dioxide from SCIAMACHY and OMI: Air mass factor algorithm development, validation, and error analysis

    NASA Astrophysics Data System (ADS)

    Lee, Chulkyu; Martin, Randall V.; van Donkelaar, Aaron; O'Byrne, Gray; Krotkov, Nickolay; Richter, Andreas; Huey, L. Gregory; Holloway, John S.

    2009-11-01

    We develop an improved retrieval of sulfur dioxide (SO2) vertical columns from two satellite instruments (SCIAMACHY and OMI) that measure ultraviolet solar backscatter. For each SCIAMACHY and OMI observation, a local air mass factor (AMF) algorithm converts line-of-sight "slant" columns to vertical columns using altitude-dependent scattering weights computed with a radiative transfer model (LIDORT), weighted by relative vertical SO2 profile (shape factor) determined locally with a global atmospheric chemistry model (GEOS-Chem). The scattering weights account for viewing geometry, surface albedo, cloud scattering, absorption by ozone, and scattering and absorption by aerosols. Absorption of radiation by mineral dust can reduce seasonal mean instrument sensitivity by 50%. Mean SO2 shape factors simulated with GEOS-Chem and used in the AMF calculation are highly consistent with airborne in situ measurements (INTEX-A and INTEX-B); differences would affect the retrieved SO2 columns by 10%. The retrieved vertical columns are validated with coincident airborne in situ measurements (INTEX-A, INTEX-B, and a campaign over east China). The annual mean AMF errors are estimated to be 35-70% in polluted regions (e.g., East Asia and the eastern United States) and less than 10% over clear ocean regions. The overall SO2 error assessment is 45-80% for yearly averages over polluted regions. Seasonal mean SO2 columns retrieved from SCIAMACHY and OMI for 2006 are significantly spatially correlated with those from GEOS-Chem, in particular over the United States (r = 0.85 for SCIAMACHY and 0.82 for OMI). A sensitivity study confirms the sensitivity of SCIAMACHY and OMI to anthropogenic SO2 emissions.

  12. Retrieval of Vertical Columns of Sulfur Dioxide From SCIAMACHY and OMI: Air Mass Factor Algorithm Development and Validation

    NASA Astrophysics Data System (ADS)

    Lee, C.; Martin, R. V.; Donkelaar, A. V.; O'Byrne, G.; Krotkov, N.; Richter, A.; Huey, G.; Holloway, J. S.

    2009-05-01

    Sulfur dioxide (SO2) is released into the atmosphere as a result of both anthropogenic activities and natural phenomena. SO2 oxidizes rapidly in the atmosphere, leading to aerosol formation and acid deposition. Outstanding questions exist about SO2 emissions and its atmospheric chemistry. Global mapping of atmospheric SO2 concentrations can provide critical information on its emissions and transport and generally improve scientific understanding of its atmospheric chemistry. Here, we present an improved retrieval of sulfur dioxide (SO2) vertical columns from satellite instruments (SCIAMACHY and OMI) that measure solar backscattered UV radiance. Particular attention is devoted to development of a local air mass factor (AMF) algorithm to convert slant columns to vertical columns. For each SCIAMACHY and OMI observation, we calculate an AMF from the relative vertical SO2 distribution (shape factor) determined locally with a 3-D global model of atmospheric chemistry (GEOS-Chem), weighted by altitude-dependent scattering weights computed with a radiative transfer model (LIDORT). Seasonal mean instrument sensitivity to SO2 (AMF) is generally twice as high over ocean than land. Mineral dust can reduce seasonal mean instrument sensitivity by 50%. Mean relative vertical profiles of SO2 simulated with GEOS-Chem and used in the AMF calculation are highly consistent with airborne in situ measurements (INTEX-A and INTEX-B); differences would affect the retrieved SO2 columns by 10%. The retrieved vertical columns are validated (r = 0.9) with coincident airborne in-situ measurements (INTEX-A, INTEX-B, and a campaign over East China). A global uniform AMF would reduce the correlation with aircraft measurements by 0.1 - 0.2. The overall error assessment leads to 45 - 80% errors for yearly averages over the polluted regions. Seasonal mean SO2 columns retrieved from SCIAMACHY and OMI for 2006 are significantly spatially correlated with those from GEOS-Chem, in particular over the

  13. Intercomparison of OMI NO2 and HCHO air mass factor calculations: recommendations and best practices for retrievals

    NASA Astrophysics Data System (ADS)

    Lorente Delgado, Alba; Klaas Boersma, Folkert; Hilboll, Andreas; Richter, Andreas; Yu, Huan; van Roozendael, Michel; Dörner, Steffen; Wagner, Thomas; Barkley, Michael; Lamsal, Lok; Lin, Jintai; Liu, Mengyao

    2016-04-01

    We present a detailed comparison of the air mass factor (AMF) calculation process used by various research groups for OMI satellite retrievals of NO2 and HCHO. Although satellite retrievals have strongly improved over the last decades, there is still a need to better understand and reduce the uncertainties associated with every retrieval step of satellite data products, such as the AMF calculation. Here we compare and evaluate the different approaches used to calculate AMFs by several scientific groups (KNMI (WUR), IASB-BIRA, IUP-UNI. BREMEN, MPI-C, NASA GSFC, LEICESTER UNI. and PEKING UNI.). Each group calculated altitude dependent (box-) AMFs and clear sky and total tropospheric AMFs for several OMI orbits. First, European groups computed AMFs for one OMI orbit using common settings for the choice of surface albedo data, terrain height, cloud treatment and a priori vertical profile. Second, every group computed AMFs for two complete days in different seasons using preferred settings for the ancillary data and cloud treatment as a part of a Round Robin exercise. Box-AMFs comparison showed good consistency and underlined the importance of a correct treatment of the physical processes affecting the effective light path and the vertical discretization of the atmosphere. Using common settings, tropospheric NO2 AMFs in polluted pixels on average agreed within 4.7% whereas in remote pixels agreed within 3.5%. Using preferred settings relative differences between AMFs increase up to 15-30%. This increase is traced back to the different choices and assumptions made throughout the AMF calculation, which affect the final AMF values and thus the uncertainty in the AMF calculation. Differences between state of the art cloud treatment approaches highlight the importance of an accurate cloud correction: total and clear sky AMFs in polluted conditions differ by up to 40% depending on the retrieval scenario. Based on the comparison results, specific recommendations on best

  14. Air Emissions Factors and Quantification

    EPA Pesticide Factsheets

    Emissions factors are used in developing air emissions inventories for air quality management decisions and in developing emissions control strategies. This area provides technical information on and support for the use of emissions factors.

  15. Relationships between submicrometer particulate air pollution and air mass history in Beijing, China, 2004 2006

    NASA Astrophysics Data System (ADS)

    Wehner, B.; Birmili, W.; Ditas, F.; Wu, Z.; Hu, M.; Liu, X.; Mao, J.; Sugimoto, N.; Wiedensohler, A.

    2008-10-01

    The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Beijing depends to large extent on the history of the synoptic scale air masses. A first approach based on manual back trajectory classification yielded differences in particulate matter mass concentration by a factor of two between four different air mass categories, including three main wind directions plus the case of stagnant air masses. A back trajectory cluster analysis refined these results, yielding a total of six trajectory clusters. Besides the large scale wind direction, the transportation speed of an air mass was found to play an essential role on the PM concentrations in Beijing. Slow-moving air masses were shown to be associated with an effective accumulation of surface-based anthropogenic emissions due to both, an increased residence time over densely populated land, and their higher degree of vertical stability. For the six back trajectory clusters, differences in PM1 mass concentrations by a factor of 3.5, in the mean air mass speed by a factor of 6, and in atmospheric visibility by a factor of 4 were found. The main conclusion is that the air quality in Beijing is not only degraded by anthropogenic aerosol sources from within the megacity, but also by sources across the entire Northwest China plain depending on the meteorological situation.

  16. Relationships between submicrometer particulate air pollution and air mass history in Beijing, China, 2004-2006

    NASA Astrophysics Data System (ADS)

    Wehner, B.; Birmili, W.; Ditas, F.; Wu, Z.; Hu, M.; Liu, X.; Mao, J.; Sugimoto, N.; Wiedensohler, A.

    2008-06-01

    The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Beijing depends to large extent on the history of the synoptic scale air masses. A first approach based on manual back trajectory classification yielded differences in particulate matter mass concentration (PM1 and PM10) by a factor of two between four different air mass categories, including three main wind directions plus the case of stagnant air masses. A back trajectory cluster analysis refined these results, yielding a total of six trajectory clusters. Besides the large scale wind direction, the transportation speed of an air mass was found to play an essential role on the PM concentrations in Beijing. Slow-moving air masses were shown to be associated with an effective accumulation of surface-based anthropogenic emissions due to both, an increased residence time over densely populated land, and their higher degree of vertical stability. For the six back trajectory clusters, differences in PM1 mass concentrations by a factor of 3.5, in the mean air mass speed by a factor of 6, and in atmospheric visibility by a factor of 4 were found. The main conclusion is that the air quality in Beijing is not only degraded by anthropogenic aerosol sources from within the megacity, but also by sources across the entire Northwest China plain depending on the meteorological situation.

  17. The Effective Mass of a Ball in the Air

    ERIC Educational Resources Information Center

    Messer, J.; Pantaleone, J.

    2010-01-01

    The air surrounding a projectile affects the projectile's motion in three very different ways: the drag force, the buoyant force, and the added mass. The added mass is an increase in the projectile's inertia from the motion of the air around it. Here we experimentally measure the added mass of a spherical projectile in air. The results agree well…

  18. Evolution of Southern Hemisphere spring air masses observed by HALOE

    NASA Technical Reports Server (NTRS)

    Pierce, R. Bradley; Grose, William L.; Russell, James M., III; Tuck, Adrian F.

    1994-01-01

    The evolution of Southern Hemisphere air masses observed by the Halogen Occultation Experiment (HALOE) during September 21 through October 15, 1992, is investigated using isentropic trajectories computed from United Kingdom Meteorological Office (UKMO) assimilated winds and temperatures. Maps of constituent concentrations are obtained by accumulation of air masses from previous HALOE occultations. Lagged correlations between initial and subsequent HALOE observations of the same air mass are used to validate the air mass trajectories. High correlations are found for lag times as large as 10 days. Frequency distributions of the air mass constituent concentrations are used to examine constituent distributions in and around the Southern Hemisphere polar vortex.

  19. Air Mass Frequency during Precipitation Events in the United States Northern Plains

    NASA Astrophysics Data System (ADS)

    Loveless, D. M.; Sharr, N. J.; Baum, A.; Contract, J. S.; DePasquale, R.; Godek, M. L.

    2013-12-01

    Since 1980, numerous billion-dollar disasters have affected the Northern Plains of the United States, including nine droughts and four floods. Given the region's large agricultural sector, the ability to accurately forecast the frequency and quantity of precipitation events here is imperative as it has a major impact on the economy of states in the region. The atmospheric environment present during precipitation events can largely be described by the presiding air mass conditions since air masses characterize a multitude of meteorological variables at one time over a large region. Therefore, understanding the relationship between air masses and rainfall episodes can contribute to improved precipitation forecasts. The goal of this research is to add knowledge to current understandings of the factors responsible for precipitation in the Northern Plains through an assessment of synoptic air mass conditions. The Spatial Synoptic Classification is used to categorize 30 years of daily air mass types across the region and daily precipitation is acquired from the United States Historical Climatological Network at stations in close proximity. Air mass frequencies are then analyzed for all regional precipitation events and rainfall categories are developed based on precipitation quantity. Both annual and seasonal air mass frequencies are assessed at the time of precipitation events. Additionally, air mass frequencies are obtained for positive and negative phases of the Pacific/North American Pattern to examine the influence of a teleconnection forcing factor on the air mass types responsible for producing precipitation quantities. Results indicate that the Transitional (TR) air mass, associated with changing air mass conditions commonly related to passing fronts, is not the leading producer of rainfall in the region. The TR is generally responsible for only 10-20% of regional precipitation, which often is classed in a heavy rainfall category. All moist air mass varieties are

  20. Ions in oceanic and continental air masses

    SciTech Connect

    Tanner, D.J.; Eisele, F.L. )

    1991-01-20

    Measurements of tropospheric ions and several trace atmospheric neutral species have been performed at Cheeka Peak Research Station and at Mauna Loa Observatory. Two new positive ion species at masses 114 and 102 have been identified as protonated caprolactam and a saturated 6-carbon primary amine, respectively. In the negative ion spectrum, methane sulfonic acid (MSA) has been identified as the parent species responsible for an ion commonly observed at mass 95 during these two studies. The diurnal variations of gas phase H{sub 2}SO{sub 4} and MSA were also measured at Cheeka Peak and have typically been found to be present in the sub-ppt range. Ion assisted measurements at Mauna Loa Observatory of pyridine and ammonia indicate concentrations of 2.5 and 70 ppt, respectively, with at least a factor of 2 uncertainty. Interesting variations and potential sources of several of the observed ions are also discussed.

  1. Isentropic analysis of polar cold air mass streams

    NASA Astrophysics Data System (ADS)

    Iwasaki, Toshiki; Kanno, Yuki

    2015-04-01

    1. Introduction A diagnostic method is presented of polar cold air mass streams defined below a threshold potential temperature. The isentropic threshold facilitates a Lagrangian view of the cold air mass streams from diabatic generation to disappearance. 2. Mass-weighted isentropic zonal mean (MIM) cold air streams In winter hemispheres, MIM's mass stream functions show a distinct extratropical direct (ETD) cell in addition to the Hadley cell. The mass stream functions have local maxima at around (280K, 45N) for NH winter and, around (280K, 50S) for SH winter. Thus, =280K may be appropriate to a threshold of the polar cold air mass for both hemispheres. The high-latitude downward motion indicates the diabatic generation of cold air mass, whereas the mid-latitude equatorward flow does its outbreak. The strength of equatorward flow is under significant control of wave-mean flow interactions. 3. Geographical distribution of the cold air mass streams in the NH winter In the NH winter, the polar cold air mass flux has two distinct mainstreams, hereafter called as East Asian (EA) stream and the North American (NA) stream. The former grows over the northern part of the Eurasian continent, turns down southeastward toward East Asia and disappears over the western North Pacific Ocean. The latter grows over the Arctic Ocean, flows toward the East Coast of North America and disappears over the western North Atlantic Ocean. These coincide well with main routes of cold surges. 4. Comparison between NH and SH winter streams The cold air mass streams in NH winter are more asymmetric than those in SH winter. The NH total cold air mass below =280K is about 1.5 times greater than the SH one. These come mainly from the topography and land-sea distribution. The mid-latitude mountains steer the cold air mass streams on the northern sides and enhance the residence time over its genesis region.

  2. An objective definition of air mass types affecting Athens, Greece; the corresponding atmospheric pressure patterns and air pollution levels.

    PubMed

    Sindosi, O A; Katsoulis, B D; Bartzokas, A

    2003-08-01

    This work aims at defining characteristic air mass types that dominate in the region of Athens, Greece during the cold (November-March) and the warm (May-September) period of the year and also at evaluating the corresponding concentration levels of the main air pollutants. For each air mass type, the mean atmospheric pressure distribution (composite maps) over Europe and the Mediterranean is estimated in order to reveal the association of atmospheric circulation with air pollution levels in Athens. The data basis for this work consists of daily values of thirteen meteorological and six pollutant parameters covering the period 1993-97. The definition of the characteristic air mass types is attempted objectively by using the methods of Factor Analysis and Cluster Analysis. The results show that during the cold period of the year there are six prevailing air mass types (at least 3% of the total number of days) and six infrequent ones. The examination of the corresponding air pollution concentration levels shows that the primary air pollutants appear with increased concentrations when light or southerly winds prevail. This is usually the case when a high pressure system is located over the central Mediterranean or a low pressure system lays over south Italy, respectively. Low levels of the primary pollutants are recorded under northeasterly winds, mainly caused by a high pressure system over Ukraine. During the warm period of the year, the southwestern Asia thermal low and the subtropical anticyclone of the Atlantic Ocean affect Greece. Though these synoptic systems cause almost stagnant conditions, four main air mass types are dominant and ten others, associated with extreme weather, are infrequent. Despite the large amounts of total solar radiation characterizing this period, ozone concentrations remain at low levels in central Athens because of its destruction by nitric oxide.

  3. Monitoring Trace Contaminants in Air Via Ion Trap Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Palmer, Peter T.; Karr, Dane; Pearson, Richard; Valero, Gustavo; Wong, Carla

    1995-01-01

    Recent passage of the Clean Air Act with its stricter regulation of toxic gas emissions, and the ever-growing number of applications which require faster turnaround times between sampling and analysis are two major factors which are helping to drive the development of new instrument technologies for in-situ, on-line, real-time monitoring. The ion trap, with its small size, excellent sensitivity, and tandem mass spectrometry capability is a rapidly evolving technology which is well-suited for these applications. In this paper, we describe the use of a commercial ion trap instrument for monitoring trace levels of chlorofluorocarbons (CFCs) and volatile organic compounds (VOCs) in air. A number of sample introduction devices including a direct transfer line interface, short column GC, and a cryotrapping interface are employed to achieve increasing levels of sensitivity. MS, MS/MS, and MS/MS/MS methods are compared to illustrate trade-offs between sensitivity and selectivity. Filtered Noise Field (FNF) technology is found to be an excellent means for achieving lower detection limits through selective storage of the ion(s) of interest during ionization. Figures of merit including typical sample sizes, detection limits, and response times are provided. The results indicate the potential of these techniques for atmospheric assessments, the High Speed Research Program, and advanced life support monitoring applications for NASA.

  4. Where do the air masses between double tropopauses come from?

    NASA Astrophysics Data System (ADS)

    Parracho, A. C.; Marques, C. A. F.; Castanheira, J. M.

    2014-01-01

    An analysis of the origin of air masses that end up between double tropopauses (DT) in the subtropics and midlatitudes is presented. The double tropopauses were diagnosed in the ERA-Interim reanalysis (1979-2010), and the origin of air masses was analysed using the Lagrangian model FLEXPART. Different processes for the formation of double tropopauses (DT) have been suggested in the literature. Some studies have suggested that double tropopauses may occur as a response to the vertical profile of adiabatic heating, due to the residual meridional circulation, while others have put forward contradicting explanations. Whereas some studies have suggested that double tropopauses result from poleward excursions of the tropical tropopause over the extratropical one, others have argued that DTs develop in baroclinic unstable processes involving transport of air from high latitudes. In some regions, the DT structure has a semipermanent character which cannot be explained by excursions of the tropical tropopause alone. However, the results presented in this paper confirm that processes involving excursions of the tropical tropopause over the extratropical tropopause, which are therefore accompanied by intrusions of air from the tropical troposphere into the lower extratropical stratosphere, make a significant contribution for the occurrence of DTs in the subtropics and midlatitudes. Specifically, it is shown that the air between double tropopauses comes from equatorward regions, and has a higher percentage of tropospheric particles and a lower mean potential vorticity.

  5. The mass and speed dependence of meteor air plasma temperatures

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  6. The mass and speed dependence of meteor air plasma temperatures.

    PubMed

    Jenniskens, Peter; Laux, Christophe O; Wilson, Michael A; Schaller, Emily L

    2004-01-01

    The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

  7. PROSPECT - GROWTH FACTOR CONTROL OF BONE MASS

    PubMed Central

    Canalis, Ernesto

    2010-01-01

    Bone formation is determined by the number and function of osteoblasts. Cell number is governed by factors that regulate the replication and differentiation of pre-osteoblasts and factors that regulate osteoblastic cell death. Cell function is controlled by signals acting on the mature osteoblast. Platelet derived and fibroblast growth factors are bone cell mitogens. Bone morphogenetic proteins (BMP) and Wnt induce the differentiation of mesenchymal cells toward osteoblasts, and insulin-like growth factor (IGF)-I stimulates the function of mature osteoblasts and prevents their death. The activity of BMP, Wnt and IGF-I is modulated by extracellular antagonists or binding proteins. Changes in growth factor synthesis and activity may play a role in the pathogenesis of selected forms of osteoporosis, and alterations in the expression or binding of the extracellular antagonists can be associated with changes in bone mass. Current approaches to bone anabolic therapies for osteoporosis include the administration of a growth factor, such as IGF-I, or the neutralization of an antagonist. Ideally, the targeting of an anabolic agent should be specific to bone to preclude non-skeletal unwanted side effects. Clinical trials are needed to determine the long-term effectiveness and safety of novel anabolic agents for the management of osteoporosis. PMID:19718659

  8. Enhancement of acidic gases in biomass burning impacted air masses over Canada

    NASA Technical Reports Server (NTRS)

    Lefer, B. L.; Talbot, R. W.; Harriss, R. C.; Bradshaw, J. D.; Sandholm, S. T.; Olson, J. O.; Sachse, G. W.; Collins, J.; Shipham, M. A.; Blake, D. R.

    1994-01-01

    Biomass-burning impacted air masses sampled over central and eastern Canada during the summer of 1990 as part of ABLE 3B contained enhanced mixing ratios of gaseous HNO3, HCOOH, CH3COOH, and what appears to be (COOH)2. These aircraft-based samples were collected from a variety of fresh burning plumes and more aged haze layers from different source regions. Values of the enhancement factor, delta X/delta CO, where X represents an acidic gas, for combustion-impacted air masses sampled both near and farther away from the fires, were relatively uniform. However, comparison of carboxylic acid emission ratios measured in laboratory fires to field plume enhancement factors indicates significant in-plume production of HCOOH. Biomass-burning appears to be an important source of HNO3, HCOOH, and CH3COOH to the troposphere over subarctic Canada.

  9. Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger

    NASA Astrophysics Data System (ADS)

    Dugaria, S.; Moro, L.; Del, D., Col

    2015-11-01

    The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.

  10. High-Altitude Air Mass Zero Calibration of Solar Cells

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Snyder, David B.

    2005-01-01

    Air mass zero calibration of solar cells has been carried out for several years by NASA Glenn Research Center using a Lear-25 aircraft and Langley plots. The calibration flights are carried out during early fall and late winter when the tropopause is at the lowest altitude. Measurements are made starting at about 50,000 feet and continue down to the tropopause. A joint NASA/Wayne State University program called Suntracker is underway to explore the use of weather balloon and communication technologies to characterize solar cells at elevations up to about 100 kft. The balloon flights are low-cost and can be carried out any time of the year. AMO solar cell characterization employing the mountaintop, aircraft and balloon methods are reviewed. Results of cell characterization with the Suntracker are reported and compared with the NASA Glenn Research Center aircraft method.

  11. Temporal and modal characterization of DoD source air toxic emission factors: final report

    EPA Science Inventory

    This project tested three, real-/near real-time monitoring techniques to develop air toxic emission factors for Department of Defense (DoD) platform sources. These techniques included: resonance enhanced multi photon ionization time of flight mass spectrometry (REMPI-TOFMS) for o...

  12. Mass transfer characteristics of bisporus mushroom ( Agaricus bisporus) slices during convective hot air drying

    NASA Astrophysics Data System (ADS)

    Ghanbarian, Davoud; Baraani Dastjerdi, Mojtaba; Torki-Harchegani, Mehdi

    2016-05-01

    An accurate understanding of moisture transfer parameters, including moisture diffusivity and moisture transfer coefficient, is essential for efficient mass transfer analysis and to design new dryers or improve existing drying equipments. The main objective of the present study was to carry out an experimental and theoretical investigation of mushroom slices drying and determine the mass transfer characteristics of the samples dried under different conditions. The mushroom slices with two thicknesses of 3 and 5 mm were dried at air temperatures of 40, 50 and 60 °C and air flow rates of 1 and 1.5 m s-1. The Dincer and Dost model was used to determine the moisture transfer parameters and predict the drying curves. It was observed that the entire drying process took place in the falling drying rate period. The obtained lag factor and Biot number indicated that the moisture transfer in the samples was controlled by both internal and external resistance. The effective moisture diffusivity and the moisture transfer coefficient increased with increasing air temperature, air flow rate and samples thickness and varied in the ranges of 6.5175 × 10-10 to 1.6726 × 10-9 m2 s-1 and 2.7715 × 10-7 to 3.5512 × 10-7 m s-1, respectively. The validation of the Dincer and Dost model indicated a good capability of the model to describe the drying curves of the mushroom slices.

  13. A determination of character and frequency changes in air masses using a spatial synoptic classification

    NASA Astrophysics Data System (ADS)

    Kalkstein, Laurence S.; Sheridan, Scott C.; Graybeal, Daniel Y.

    1998-09-01

    Of the numerous climate change studies which have been performed, few of these have analyzed recent trends using an air mass-based approach. The air mass approach is superior to simple trend analysis, as it can identify patterns which may be too subtle to influence the entire climate record. The recently-developed spatial synoptic classification (SSC) is thus used to identify trends over the contiguous United States for summer and winter seasons from 1948 to 1993. Both trends in air mass frequency and character have been assessed.The most noteworthy trend in frequency is a decline in air mass transitional days (TR) during both seasons. In winter, decreases of up to 1% per decade are noted in parts of the central U.S. Other notable trends include a decrease in moist tropical (MT) air in winter, and an increase in MT in summer over the southeastern states.Numerous national and local air mass character changes have been uncovered. A large overall upward trend in cloudiness is noted in summer. All air masses feature an overnight increase, yet afternoon cloudiness increases are generally limited to the three dry air masses. Also in summer, a significant warming and increase in dew point of MT air has occurred at many locales. The most profound winter trend is a large decrease in dew point (up to 1.5°C per decade) in the dry polar (DP) air mass over much of the eastern states.

  14. Air-to-Air Target Acquisition: Factors and Means of Improvement.

    DTIC Science & Technology

    1980-03-01

    TARGET ACQUISITION: FACTORS AND MEANS OF IMPROVEMENT INTRODUCTION I Air-to-air target detection is a required skill for safety purposes in commercial and...personnel skills and training programs were evaluated in terms of their relation- ship to air-to-ground target detection. Of particular interest is an...highly motivLted, vigilant at the task, and well trained, although no particular form of training is specified. Generally speaking , the parameters related

  15. Emission factors of air toxics from semiconductor manufacturing in Korea.

    PubMed

    Eom, Yun-Sung; Hong, Ji-Hyung; Lee, Suk-Jo; Lee, Eun-Jung; Cha, Jun-Seok; Lee, Dae-Gyun; Bang, Sun-Ae

    2006-11-01

    The development of local, accurate emission factors is very important for the estimation of reliable national emissions and air quality management. For that, this study is performed for pollutants released to the atmosphere with source-specific emission tests from the semiconductor manufacturing industry. The semiconductor manufacturing industry is one of the major sources of air toxics or hazardous air pollutants (HAPs); thus, understanding the emission characteristics of the emission source is a very important factor in the development of a control strategy. However, in Korea, there is a general lack of information available on air emissions from the semiconductor industry. The major emission sources of air toxics examined from the semiconductor manufacturing industry were wet chemical stations, coating applications, gaseous operations, photolithography, and miscellaneous devices in the wafer fabrication and semiconductor packaging processes. In this study, analyses of emission characteristics, and the estimations of emission data and factors for air toxics, such as acids, bases, heavy metals, and volatile organic compounds from the semiconductor manufacturing process have been performed. The concentration of hydrogen chloride from the packaging process was the highest among all of the processes. In addition, the emission factor of total volatile organic compounds (TVOCs) for the packaging process was higher than that of the wafer fabrication process. Emission factors estimated in this study were compared with those of Taiwan for evaluation, and they were found to be of similar level in the case of TVOCs and fluorine compounds.

  16. Microbial air quality in mass transport buses and work-related illness among bus drivers of Bangkok Mass Transit Authority.

    PubMed

    Luksamijarulkul, Pipat; Sundhiyodhin, Viboonsri; Luksamijarulkul, Soavalug; Kaewboonchoo, Orawan

    2004-06-01

    The air quality in mass transport buses, especially air-conditioned buses may affect bus drivers who work full time. Bus numbers 16, 63, 67 and 166 of the Seventh Bus Zone of Bangkok Mass Transit Authority were randomly selected to investigate for microbial air quality. Nine air-conditioned buses and 2-4 open-air buses for each number of the bus (36 air-conditioned buses and 12 open-air buses) were included. Five points of in-bus air samples in each studied bus were collected by using the Millipore A ir Tester Totally, 180 and 60 air samples collected from air-conditioned buses and open-air buses were cultured for bacterial and fungal counts. The bus drivers who drove the studied buses were interviewed towards histories of work-related illness while working. The results revealed that the mean +/- SD of bacterial counts in the studied open-air buses ranged from 358.50 +/- 146.66 CFU/m3 to 506 +/- 137.62 CFU/m3; bus number 16 had the highest level. As well as the mean +/- SD of fungal counts which ranged from 93.33 +/- 44.83 CFU/m3 to 302 +/- 294.65 CFU/m3; bus number 166 had the highest level. Whereas, the mean +/- SD of bacterial counts in the studied air-conditioned buses ranged from 115.24 +/- 136.01 CFU/m3 to 244.69 +/- 234.85 CFU/m3; bus numbers 16 and 67 had the highest level. As well as the mean +/- SD of fungal counts which rangedfrom 18.84 +/- 39.42 CFU/m3 to 96.13 +/- 234.76 CFU/m3; bus number 166 had the highest level. When 180 and 60 studied air samples were analyzed in detail, it was found that 33.33% of the air samples from open-air buses and 6.11% of air samples from air-conditioned buses had a high level of bacterial counts (> 500 CFU/m3) while 6.67% of air samples from open-air buses and 2.78% of air samples from air-conditioned buses had a high level of fungal counts (> 500 CFU/m3). Data from the history of work-related illnesses among the studied bus drivers showed that 91.67% of open-air bus drivers and 57.28% of air-conditioned bus drivers had

  17. Mass gathering medicine: event factors predicting patient presentation rates.

    PubMed

    Locoh-Donou, Samuel; Yan, Guofen; Berry, Thomas; O'Connor, Robert; Sochor, Mark; Charlton, Nathan; Brady, William

    2016-08-01

    This study was conducted to identify the event characteristics of mass gatherings that predict patient presentation rates held in a southeastern US university community. We conducted a retrospective review of all event-based emergency medical services (EMS) records from mass gathering patient presentations over an approximate 23 month period, from October 24, 2009 to August 27, 2011. All patrons seen by EMS were included. Event characteristics included: crowd size, venue percentage filled seating, venue location (inside/outside), venue boundaries (bounded/unbounded), presence of free water (i.e., without cost), presence of alcohol, average heat index, presence of climate control (i.e., air conditioning), and event category (football, concerts, public exhibitions, non-football athletic events). We identified 79 mass gathering events, for a total of 670 patient presentations. The cumulative patron attendance was 917,307 persons. The patient presentation rate (PPR) for each event was calculated as the number of patient presentations per 10,000 patrons in attendance. Overdispersed Poisson regression was used to relate this rate to the event characteristics while controlling for crowd size. In univariate analyses, increased rates of patient presentations were strongly associated with outside venues [rate ratio (RR) = 3.002, p < 0.001], unbounded venues (RR = 2.839, p = 0.001), absence of free water (RR = 1.708, p = 0.036), absence of climate control (RR = 3.028, p < 0.001), and a higher heat index (RR = 1.211 per 10-unit heat index increase, p = 0.003). The presence of alcohol was not significantly associated with the PPR. Football events had the highest PPR, followed sequentially by public exhibitions, concerts, and non-football athletic events. In multivariate models, the strong predictors from the univariate analyses retained their predictive significance for the PPR, together with heat index and percent seating. In the setting of mass event

  18. Mathematical modeling of heat exchange between mine air and rock mass during fire

    SciTech Connect

    A.E. Krasnoshtein; B.P. Kazakov; A.V. Shalimov

    2006-05-15

    Solution of problems on heat exchange between ventilating air and rock mass and on gas admixture propagation in mine workings serve as a base for considering changes in heat-gas-air state at a mine after inflammation. The presented mathematical relations allow calculation of a varied velocity and movement direction of air flows, their temperatures and smoking conditions during fire.

  19. Spatial operator factorization and inversion of the manipulator mass matrix

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo; Kreutz-Delgado, Kenneth

    1992-01-01

    This paper advances two linear operator factorizations of the manipulator mass matrix. Embedded in the factorizations are many of the techniques that are regarded as very efficient computational solutions to inverse and forward dynamics problems. The operator factorizations provide a high-level architectural understanding of the mass matrix and its inverse, which is not visible in the detailed algorithms. They also lead to a new approach to the development of computer programs or organize complexity in robot dynamics.

  20. Bioaccumulation Potential Of Air Contaminants: Combining Biological Allometry, Chemical Equilibrium And Mass-Balances To Predict Accumulation Of Air Pollutants In Various Mammals

    SciTech Connect

    Veltman, Karin; McKone, Thomas E.; Huijbregts, Mark A.J.; Hendriks, A. Jan

    2009-03-01

    In the present study we develop and test a uniform model intended for single compartment analysis in the context of human and environmental risk assessment of airborne contaminants. The new aspects of the model are the integration of biological allometry with fugacity-based mass-balance theory to describe exchange of contaminants with air. The developed model is applicable to various mammalian species and a range of chemicals, while requiring few and typically well-known input parameters, such as the adult mass and composition of the species, and the octanol-water and air-water partition coefficient of the chemical. Accumulation of organic chemicals is typically considered to be a function of the chemical affinity forlipid components in tissues. Here, we use a generic description of chemical affinity for neutral and polar lipids and proteins to estimate blood-air partition coefficients (Kba) and tissue-air partition coefficients (Kta) for various mammals. This provides a more accurate prediction of blood-air partition coefficients, as proteins make up a large fraction of total blood components. The results show that 75percent of the modeled inhalation and exhalation rate constants are within a factor of 2 from independent empirical values for humans, rats and mice, and 87percent of the predicted blood-air partition coefficients are within a factor of 5 from empirical data. At steady-state, the bioaccumulation potential of air pollutants is shown to be mainly a function of the tissue-air partition coefficient and the biotransformation capacity of the species and depends weakly on the ventilation rate and the cardiac output of mammals.

  1. A Comparison of the Red Green Blue Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Folmer, Michael; Dunion, Jason

    2014-01-01

    The Red Green Blue (RGB) Air Mass imagery is derived from multiple channels or paired channel differences. Multiple channel products typically provide additional information than a single channel can provide alone. The RGB Air Mass imagery simplifies the interpretation of temperature and moisture characteristics of air masses surrounding synoptic and mesoscale features. Despite the ease of interpretation of multiple channel products, the combination of channels and channel differences means the resulting product does not represent a quantity or physical parameter such as brightness temperature in conventional single channel satellite imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles of temperature, moisture, and ozone can provide insight about the air mass represented on the RGB Air Mass product and provide confidence in the product and representation of air masses despite the lack of a quantity to reference for interpretation. This study focuses on RGB Air Mass analysis of Hurricane Sandy as it moved north along the U.S. East Coast, while transitioning to a hybrid extratropical storm. Soundings and total column ozone retrievals were analyzed using data from the Cross-track Infrared and Advanced Technology Microwave Sounder Suite (CrIMSS) on the Suomi National Polar Orbiting Partnership satellite and the Atmospheric Infrared Sounder (AIRS) on the National Aeronautics and Space Administration Aqua satellite along with dropsondes that were collected from National Oceanic and Atmospheric Administration and Air Force research aircraft. By comparing these datasets to the RGB Air Mass, it is possible to capture quantitative information that could help in analyzing the synoptic environment enough to diagnose the onset of extratropical transition. This was done by identifying any stratospheric air intrusions (SAIs) that existed in the vicinity of Sandy as the wind

  2. Air Mass Origin in the Arctic and its Response to Future Warming

    NASA Technical Reports Server (NTRS)

    Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

    2014-01-01

    We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

  3. Aerosols in polluted versus nonpolluted air masses Long-range transport and effects on clouds

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Van Valin, C. C.; Castillo, R. C.; Kadlecek, J. A.; Ganor, E.

    1986-01-01

    To assess the influence of anthropogenic aerosols on the physics and chemistry of clouds in the northeastern United States, aerosol and cloud-drop size distributions, elemental composition of aerosols as a function of size, and ionic content of cloud water were measured on Whiteface Mountain, NY, during the summers of 1981 and 1982. In several case studies, the data were cross-correlated with different air mass types - background continental, polluted continental, and maritime - that were advected to the sampling site. The results are the following: (1) Anthropogenic sources hundreds of kilometers upwind cause the small-particle (accumulation) mode number to increase from hundreds of thousands per cubic centimeter and the mass loading to increase from a few to several tens of micrograms per cubic meter, mostly in the form of sulfur aerosols. (2) A significant fraction of anthropogenic sulfur appears to act as cloud condensation nuclei (CCN) to affect the cloud drop concentration. (3) Clouds in Atlantic maritime air masses have cloud drop spectra that are markedly different from those measured in continental clouds. The drop concentration is significantly lower, and the drop size spectra are heavily skewed toward large drops. (4) Effects of anthropogenic pollutants on cloud water ionic composition are an increase of nitrate by a factor of 50, an increase of sulfate by more than one order of magnitude, and an increase of ammonium ion by a factor of 7. The net effect of the changes in ionic concentrations is an increase in cloud water acidity. An anion deficit even in maritime clouds suggests an unknown, possibly biogenic, source that could be responsible for a pH below neutral, which is frequently observed in nonpolluted clouds.

  4. VOC Composition of Air Masses Transported from Asia to the U.S. West Coast

    NASA Astrophysics Data System (ADS)

    de Gouw, J.; Warneke, C.; Kuster, B.; Parrish, D.; Holloway, J.; Huebler, G.; Fehsenfeld, F.

    2002-12-01

    Airborne measurements of volatile organic compounds (VOCs) were performed using a proton-transfer-reaction mass spectrometer (PTR-MS) operated onboard a NOAA WP-3 aircraft during the Intercontinental Transport and Chemical Transformation (ITCT) experiment in 2002. Enhancements of acetone (CH3COCH3), methanol (CH3OH), acetonitrile (CH3CN) and in some cases benzene were observed in air masses that were impacted by outflow from Asia. The enhancement ratios with respect to carbon monoxide are compared to emission factors for fossil fuel combustion and biomass burning, which gives some insight into the sources responsible for the pollution. The observed mixing ratios for acetone, methanol and in particular acetonitrile were generally reduced in the marine boundary layer, suggesting the presence of an ocean uptake sink. The ocean uptake of acetonitrile was found to be particularly efficient in a zone with upwelling water off of the U.S. west coast. Reduced mixing ratios of acetone and methanol were observed in a stratospheric intrusion. This observation gives some information about the lifetime of these VOCs in the stratosphere. Enhanced concentrations of aromatic hydrocarbons were observed in air masses that were impacted by urban sources in California. The ratio between the concentrations of benzene, toluene and higher aromatics indicated the degree of photochemical oxidation. PTR-MS only gives information about the mass of the ions produced by proton-transfer reactions between H3O+ and VOCs in the instrument. The identification of VOCs was confirmed by coupling a gas-chromatographic (GC) column to the instrument and post-flight GC-PTR-MS analyses of canister samples collected during the flights.

  5. Elemental composition of different air masses over Jeju Island, South Korea

    NASA Astrophysics Data System (ADS)

    Kang, Jeongwon; Choi, Man-Sik; Yi, Hi-Il; Jeong, Kap-Sik; Chae, Jung-Sun; Cheong, Chang-Sik

    2013-03-01

    We investigated the characteristics (concentrations and compositional changes) of atmospheric elements in total suspended particulates through source-receptor relationships using cluster analyses to classify air mass back-trajectories arriving at Gosan, Jeju Island, South Korea, from October 2003 to December 2008. Five trajectory clusters were chosen to explain the transport regimes. Continental outflows of natural and anthropogenic aerosols from Asian dust source regions and eastern China during the colder period could increase element concentrations at Gosan. Elemental levels at Gosan decreased in air masses that passed over marine regions (East China Sea, Pacific Ocean/southern side of Kyushu Island in Japan, and East Sea/southern side of South Korea) during the warmer rainy period due to lower source intensity and dilution by the marine air mass. Anthropogenic pollutants were often major components in air masses passing over marine regions. Air mass characterization by elemental concentration and composition revealed that enrichment by non-sea-salt sulfur in the air mass originated from eastern China, indicative of the main sulfur emitter in northeast Asia. The apportionment of V and Ni by principal component analysis as a marker of heavy oil combustion suggested different residence times and deposition rates from other anthropogenic components in the air. Regionally intermediate concentrations of pollutants were found in the atmosphere over the Korean peninsula.

  6. Adolescent obesity, bone mass and cardiometabolic risk factors

    PubMed Central

    Pollock, Norman K; Bernard, Paul J; Gutin, Bernard; Davis, Catherine L; Zhu, Haidong; Dong, Yanbin

    2010-01-01

    Objective To compare bone mass between overweight adolescents with and without cardiometabolic risk factors (CMR). Associations of bone mass with CMR and adiposity were also determined. Study design Overweight adolescents (aged 14–18 years) were classified in Healthy (n=55), 1CMR (n=46) or ≥2CMR (n=42). CMR were measured using standard methods and defined according to pediatric definitions of metabolic syndrome. Total body bone mass, fat mass and fat-free soft tissue mass (FFST) were measured by DXA. Visceral adipose tissue (VAT) and subcutaneous abdominal adipose tissue (SAAT) were assessed using MRI. Results After controlling for age, sex, race, height and FFST, Healthy group had 5.4% and 6.3% greater bone mass than the 1CMR and ≥2CMR groups, respectively (both P<0.04). Multiple linear regression, adjusting for same covariates, revealed that VAT (β=−0.22), waist circumference (β= −0.23), homeostasis model assessment of insulin resistance (β= −0.23) and HDL-cholesterol (β=0.22) were associated with bone mass (all P<0.04). There was a trend towards a significant inverse association between bone mass and fasting glucose (P=0.056). No relations were found between bone mass and fat mass, SAAT, BP or triglycerides. Conclusion Being overweight with metabolic abnormalities, particularly insulin resistance, low HDL-cholesterol and visceral adiposity, may adversely influence adolescent bone mass. PMID:21232765

  7. The Analysis of PPM Levels of Gases in Air by Photoionization Mass Spectrometry

    ERIC Educational Resources Information Center

    Driscoll, John N.; Warneck, Peter

    1973-01-01

    Discusses analysis of trace gases in air by photoionization mass spectrometer. It is shown that the necessary sensitivity can be obtained by eliminating the UV monochromator and using direct ionization with a hydrogen light source. (JP)

  8. [Etiological and exacerbation factors for COPD. Air pollution].

    PubMed

    Ogawa, Kazumasa; Kishi, Kazuma

    2016-05-01

    Recently, it has been found that the number of patients with chronic obstructive pulmonary disease (COPD) who do not have a history of smoking is higher than expected, and a number of factors affect the development of COPD. Although adequate evidence for the relation of ambient air pollution, including the presence of particulate matter (PM2.5), with the development of COPD is lacking, higher mortality from respiratory and cardiovascular diseases has been reported among patients exposed to air pollution for a long time. In addition, several reports have pointed out the possibility that acute exacerbation of COPD can be caused by short-term exposure to air pollution. Tobacco smoke is the main cause of highly concentrated PM2.5 indoors, and second hand smoke is related with the development of COPD and the high mortality from COPD. In developing countries, biomass fuel combustion contributes to COPD, especially among housewives who do not smoke.

  9. Experimental Determination of the Mass of Air Molecules from the Law of Atmospheres.

    ERIC Educational Resources Information Center

    Hayn, Carl H.; Galvin, Vincent, Jr.

    1979-01-01

    A gas pressure gauge has been constructed for use in a student experiment involving the law of atmospheres. From pressure data obtained at selected elevations the average mass of air molecules is determined and compared to that calculated from the molecular weights and percentages of constituents to the air. (Author/BB)

  10. DNAPL REMOVAL MECHANISMS AND MASS TRANSFER CHARACTERISTICS DURING COSOLVENT-AIR FLOODING

    EPA Science Inventory

    The concurrent injection of cosolvent and air, a cosolvent-air (CA) flood was recently suggested for a dense nonaqueous phase liquid (DNAPL) remediation technology. The objectives of this study were to elucidate the DNAPL removal mechanisms of the CA flood and to quantify mass t...

  11. Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

    NASA Astrophysics Data System (ADS)

    Rozwadowska, Anna; Stachlewska, Iwona S.; Makuch, P.; Markowicz, K. M.; Petelski, T.; Strzałkowska, A.; Zieliński, T.

    2013-05-01

    Properties of atmospheric aerosols and solar radiation reaching the Earth's surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.

  12. [Atmospheric air pollution: a risk factor for COPD?].

    PubMed

    Allain, Y-M; Roche, N; Huchon, G

    2010-04-01

    Tobacco smoking is the leading cause of COPD worldwide but other risk factors have been recognized. Air pollution is one of them, but its exact role in the development of COPD is hard to demonstrate. Its physiological effects on lung function have only been studied since the nineties by long and tedious cohort studies. Difficulties arise from the heterogeneity of air pollution (gas and particles); thus, its respiratory effects have to be examined for every component separately, and in different populations. It is also necessary to analyse the effects of atmospheric pollution in the short and the long term, considering both its physiological, clinical and toxicological effects, from childhood to adulthood. These factors make it difficult to obtain statistically significant results. Nevertheless, most studies seem to point to a role of air pollution in the development of COPD via oxydative stress but further studies are needed to confirm the exact effect of each component of air pollution on the respiratory tract. These studies could lead to improved public health policies and results are awaited that would identify at-risk populations, decide appropriate preventive measures and propose documented thresholds in pollution exposure... thereby limiting the spread of COPD.

  13. Fullerene Soot in Eastern China Air: Results from Soot Particle-Aerosol Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Wang, J.; Ge, X.; Chen, M.; Zhang, Q.; Yu, H.; Sun, Y.; Worsnop, D. R.; Collier, S.

    2015-12-01

    In this work, we present for the first time, the observation and quantification of fullerenes in ambient airborne particulate using an Aerodyne Soot Particle - Aerosol Mass Spectrometer (SP-AMS) deployed during 2015 winter in suburban Nanjing, a megacity in eastern China. The laser desorption and electron impact ionization techniques employed by the SP-AMS allow us to differentiate various fullerenes from other aerosol components. Mass spectrum of the identified fullerene soot is consisted by a series of high molecular weight carbon clusters (up to m/z of 2000 in this study), almost identical to the spectral features of commercially available fullerene soot, both with C70 and C60 clusters as the first and second most abundant species. This type of soot was observed throughout the entire study period, with an average mass loading of 0.18 μg/m3, accounting for 6.4% of the black carbon mass, 1.2% of the total organic mass. Temporal variation and diurnal pattern of fullerene soot are overall similar to those of black carbon, but are clearly different in some periods. Combining the positive matrix factorization, back-trajectory and analyses of the meteorological parameters, we identified the petrochemical industrial plants situating upwind from the sampling site, as the major source of fullerene soot. In this regard, our findings imply the ubiquitous presence of fullerene soot in ambient air of industry-influenced area, especially the oil and gas production regions. This study also offers new insights into the characterization of fullerenes from other environmental samples via the advanced SP-AMS technique.

  14. Improving microbial air quality in air-conditioned mass transport buses by opening the bus exhaust ventilation fans.

    PubMed

    Luksamijarulkul, Pipat; Arunchai, Nongphon; Luksamijarulkul, Soavalug; Kaewboonchoo, Orawan

    2005-07-01

    The air quality in air-conditioned mass transport buses may affect bus drivers' health. In-bus air quality improvement with the voluntary participation of bus drivers by opening the exhaust ventilation fans in the bus was implemented in the Seventh Bus Zone of Bangkok Mass Transit Authority. Four bus numbers, including bus numbers 16, 63, 67 and 166, were randomly selected to investigate microbial air quality and to observe the effect of opening the exhaust ventilation fans in the bus. With each bus number, 9 to 10 air-conditioned buses (total, 39 air-conditioned buses) were included. In-bus air samples were collected at 5 points in each studied bus using the Millipore Air Tester. A total of 195 air samples were cultured for bacterial and fungal counts. The results reveal that the exhaust ventilation fans of 17 air-conditioned buses (43.6%) were opened to ventilate in-bus air during the cycle of the bus route. The means +/- SD of bacterial counts and fungal counts in the studied buses with opened exhaust ventilation fans (83.8 +/- 70.7 and 38.0 +/- 42.8 cfu/m3) were significantly lower than those in the studied buses without opened exhaust ventilation fans (199.6 +/- 138.8 and 294.1 +/- 178.7 cfu/m3), p < 0.0005. All the air samples collected from the studied buses with opened exhaust ventilation fans were at acceptable levels (< 500 cfu/m3) compared with 4.6% of the air samples collected from the studied buses without opened exhaust ventilation fans, which had high levels (> 500 cfu/m3). Of the studied buses with opened exhaust ventilation fans (17 buses), the bacterial and fungal counts after opening the exhaust ventilation fans (68.3 +/- 33.8 and 28.3 +/- 19.3 cfu/m3) were significantly lower than those before opening the exhaust ventilation fans (158.3 +/- 116.9 and 85.3 +/- 71.2 cfu/m3), p < 0.005.

  15. Erroneous mass transit system and its tended relationship with motor vehicular air pollution (An integrated approach for reduction of urban air pollution in Lahore).

    PubMed

    Aziz, Amer; Bajwa, Ihsan Ullah

    2008-02-01

    Air pollution is threat to the lives of people living in big cities of Pakistan. In Lahore 1,250 people die annually because of air pollution. Mass transit system that can be put forth as solution to urban air pollution is contingent with right choice of system and its affiliation with motorized vehicles and nature of urban air pollution. Existing mass transit system in Lahore due to untrue operation causes surfeit discharge of motor vehicular carbon monoxide. Tended relationships of mass transit system with motorized vehicles and urban air pollution are quite noteworthy. The growing motor vehicles (a consequence of flawed public mass transit system) are potential source of urban air pollution. This paper attempts to highlight correlations and regression curves of existing mass transit system. Further it recommends a two facet approach for reduction of motor vehicular air pollution in Lahore.

  16. Diaphragm correction factors for free-air chamber standards for air kerma in x-rays.

    PubMed

    Burns, D T; Kessler, C

    2009-05-07

    At present, only a correction factor for photon transmission, k(l), is systematically applied for the entrance diaphragm of free-air chamber standards for air kerma. In the present work, the Monte Carlo code PENELOPE is used to re-evaluate k(l) for the BIPM standards and new correction factors are calculated for photon scatter and for fluorescence production in the diaphragm. An additional effect arising from electrons emitted from the diaphragm is shown to be significant at the highest photon energies. The results for the radiation qualities used for international comparisons give a combined diaphragm correction factor k(dia) = 0.9980(3) for the BIPM medium-energy standard at 250 kV. This is significantly different from the factor k(l) = 0.9996(1) in use at present and it might be concluded that differences are likely to exist for all free-air chamber standards. The effect of using a conical taper at the downstream edge of the diaphragm is shown to be negligible for these radiation qualities.

  17. Monolithic mass sensor fabricated using a conventional technology with attogram resolution in air conditions

    NASA Astrophysics Data System (ADS)

    Verd, J.; Uranga, A.; Abadal, G.; Teva, J.; Torres, F.; Pérez-Murano, F.; Fraxedas, J.; Esteve, J.; Barniol, N.

    2007-07-01

    Monolithic mass sensors for ultrasensitive mass detection in air conditions have been fabricated using a conventional 0.35μm complementary metal-oxide-semiconductor (CMOS) process. The mass sensors are based on electrostatically excited submicrometer scale cantilevers integrated with CMOS electronics. The devices have been calibrated obtaining an experimental sensitivity of 6×10-11g/cm2Hz equivalent to 0.9ag/Hz for locally deposited mass. Results from time-resolved mass measurements are also presented. An evaluation of the mass resolution have been performed obtaining a value of 2.4×10-17g in air conditions, resulting in an improvement of these devices from previous works in terms of sensitivity, resolution, and fabrication process complexity.

  18. Peroxy radicals and ozone photochemistry in air masses undergoing long-range transport

    NASA Astrophysics Data System (ADS)

    Parker, A. E.; Monks, P. S.; Jacob, M. J.; Penkett, S. A.; Lewis, A. C.; Stewart, D. J.; Whalley, L. K.; Methven, J.; Stohl, A.

    2009-09-01

    Concentrations of peroxy radicals (HO2+ΣiRiO2) in addition to other trace gases were measured onboard the UK Meteorological Office/Natural Environment Research Council British Aerospace 146-300 atmospheric research aircraft during the Intercontinental Transport of Ozone and Precursors (ITOP) campaign based at Horta Airport, Faial, Azores (38.58° N, 28.72° W) in July/August 2004. The overall peroxy radical altitude profile displays an increase with altitude that is likely to have been impacted by the effects of long-range transport. The peroxy radical altitude profile for air classified as of marine origin shows no discernable altitude profile. A range of air-masses were intercepted with varying source signatures, including those with aged American and Asian signatures, air-masses of biomass burning origin, and those that originated from the east coast of the United States. Enhanced peroxy radical concentrations have been observed within this range of air-masses indicating that long-range transported air-masses traversing the Atlantic show significant photochemical activity. The net ozone production at clear sky limit is in general negative, and as such the summer mid-Atlantic troposphere is at limit net ozone destructive. However, there is clear evidence of positive ozone production even at clear sky limit within air masses undergoing long-range transport, and during ITOP especially between 5 and 5.5 km, which in the main corresponds to a flight that extensively sampled air with a biomass burning signature. Ozone production was NOx limited throughout ITOP, as evidenced by a good correlation (r2=0.72) between P(O3) and NO. Strong positive net ozone production has also been seen in varying source signature air-masses undergoing long-range transport, including but not limited to low-level export events, and export from the east coast of the United States.

  19. A Synoptic Air Mass Approach to Defining Southwest U.S. Summer Duration and Change

    NASA Astrophysics Data System (ADS)

    Morrill, C.; Wachtel, C. J.; Godek, M. L.

    2015-12-01

    As the past decade was the warmest in the 110-year active record, and future Southwest warming is expected to be most intense in the summer season, it is important to have an updated atmospheric definition of what constitutes a Southwest summer. This is particularly true given the intensity of current drought conditions and that summers may be changing. Using weather-type data from the Spatial Synoptic Classification, this research aims to synoptically define the summer season in the Southwest since 1950. The Southwest is spatially described here by sub-region and 28 air mass stations within are chosen for air mass analysis. Daily air mass frequencies are examined to determine the dominant and less prevalent types annually and seasonally, from May to September. Then, frequencies in the middle of summer are compared to those in the seasonal fringe months to explore the possibility of a synoptic shift in the timing of the region's summer season. Finally, to further scrutinize how regional air mass frequencies have changed with time, the data are subdivided and evaluated for the 'Early record' (years prior to 1975) and 'Modern record' (post 1975). Frequency departures are tested for practical and statistical significance to characterize the strength of summer season variability. Results indicate that Dry Moderate air masses are the most common annually and in summer. Moist and transitional air masses tend to less frequent throughout the Southwest; however, frequencies vary greatly by sub-region. Wet and dry conditions are observed in accordance with the monsoon in some sub-regions, but not throughout the region. Significant changes in sub-regional air mass tendencies are identified that show the Early record experienced cooler air mass conditions (fewer tropical types and more moderate and cool types) than the Modern record. From a long-term synoptic air mass perspective, typical Southwest summers likely last from May to August. However, in the Modern record May

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

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

    2012-04-01

    . In all air masses passing the continent the organic aerosol fraction dominated the total NR-PM1. For this reason, using Positive Matrix Factorization (PMF) four organic aerosol (OA) classes that can be associated with various aerosol sources and components were identified: a highly-oxygenated OA is the major component (43% OA) while semi-volatile OA accounts for 23%. A hydrocarbon-like OA mainly resulting from industries, traffic and shipping emissions as well as particles from wood burning emissions also contribute to total OA and depend on the air mass origin. A significant variability of ozone was observed that depends on the impact of different air mass types and solar radiation.

  1. Road construction: Emissions Factors and Air Quality Impacts

    NASA Astrophysics Data System (ADS)

    Font Font, Anna M.; Baker, Timothy; Mudway, Ian; Fuller, Gary W.

    2014-05-01

    Very few studies have investigated the air pollution impacts of road construction. Over a 17 month period a congested main road in south east London was widened from two lanes to four. Emissions factors for road construction were determined and a notable deterioration in residential air quality was found with the final expanded road layout. Air quality monitoring sites measuring PM10, PM2.5, NOX, NO2 and meteorological variables were deployed on both sides of the road construction to quantify ambient air quality before, during and after the completion of the road works, with additional measurements from a nearby background site. PM10 samples were collected for oxidative potential measurements. PM10 was the only pollutant to increase during the construction; mean PM10 from the road increased by 15 µg m-3 during working hours; weekdays between 6 am and 5 pm; and on Saturdays between 6 am and 12 pm, compared to concentrations before the road works. During the construction the number of days with daily mean PM10 concentrations greater than 50 µg m-3 was more than 35 for both sides of the road, breaching the European Union Limit Value (LV). Downwind-upwind differences were used to calculate real-world PM10 emissions associated to the construction activity by means of box modelling. The quantity of PM10 emitted per area and month of construction was 0.0009 kg PM10 m-2 month-1 for the construction period. This emission factor was similar to the one used in the UK National Atmospheric Emissions Inventory (NAEI). Worst case construction emissions factors were 0.0105 kg PM10 m-2 month-1, compared to 0.0448 kg PM10 m-2 month-1 and 0.1038 kg PM10 m-2 month-1 used in current European and US inventories, respectively. After the completion of the road widening an increase in all pollutants was measured during rush hour peaks: 2-4 µg m-3 for PM10; 1 µg m-3 for PM2.5; 20 and 4 ppbv (40 and 8 µg m-3) for NOX and NO2, respectively, leading to a breach of the NO2 annual mean LV

  2. Use of exhaled breath condensate endpoints for examination of Body Mass Index as a susceptibility factor to diesel exhaust.

    EPA Science Inventory

    High and low Body Mass Index (BMI) is a risk factor for effects (e.g., premature mortality) induced by exposure to common air pollutants such as ozone and particulate matter. Diesel exhaust contributes to particulate matter levels. We examined lung responses using the exhaled bre...

  3. The Influence of Declining Air Lead Levels on Blood Lead-Air Lead Slope Factors in Children

    EPA Science Inventory

    This presentation describes calculation of blood lead-air lead slope factor within an analysis of the relationship between blood lead levels and air lead levels among participants in the National Health and Nutrition Examination Survey (NHANES). The slope factors are compared wi...

  4. Is Household Air Pollution a Risk Factor for Eye Disease?

    PubMed Central

    West, Sheila K.; Bates, Michael N.; Lee, Jennifer S.; Schaumberg, Debra A.; Lee, David J.; Adair-Rohani, Heather; Chen, Dong Feng; Araj, Houmam

    2013-01-01

    In developing countries, household air pollution (HAP) resulting from the inefficient burning of coal and biomass (wood, charcoal, animal dung and crop residues) for cooking and heating has been linked to a number of negative health outcomes, mostly notably respiratory diseases and cancers. While ocular irritation has been associated with HAP, there are sparse data on adverse ocular outcomes that may result from acute and chronic exposures. We consider that there is suggestive evidence, and biological plausibility, to hypothesize that HAP is associated with some of the major blinding, and painful, eye conditions seen worldwide. Further research on this environmental risk factor for eye diseases is warranted. PMID:24284355

  5. Thin-Film Air-Mass-Flow Sensor of Improved Design Developed

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.

    2003-01-01

    Researchers at the NASA Glenn Research Center have developed a new air-mass-flow sensor to solve the problems of existing mass flow sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other air-mass-flow sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film air-mass-flow sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-flow rate. The following figure shows a schematic of this sensor with air flowing around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no flow, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is flow, the air passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the air has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated air raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of air passing by the sensor. A current application for air-mass-flow sensors is as part of the intake system for an internal combustion engine. A mass-flow sensor is

  6. Northern East Asian Monsoon Precipitation Revealed by Air Mass Variability and Its Prediction

    NASA Astrophysics Data System (ADS)

    Son, J. H.; Seo, K. H.

    2015-12-01

    This work provides a new perspective on the major factors controlling the East Asian summer monsoon (EASM) in July, and a promising physical-statistical forecasting of the EASM ahead of summer. Dominant modes of the EASM are revealed from the variability of large-scale air masses discerned by equivalent potential temperature, and are found to be dynamically connected with the anomalous sea surface temperatures (SSTs) over the three major oceans of the world and their counterparts of prevailing atmospheric oscillation or teleconnection patterns. Precipitation over Northeast Asia (NEA) during July is enhanced by the tropical central Indian Ocean warming and central Pacific El Niño-related SST warming, the northwestern Pacific cooling off the coast of NEA, and the North Atlantic Ocean warming. Using these factors and data from the preceding spring seasons, the authors build a multiple linear regression model for seasonal forecasting. The cross-validated correlation skill predicted for the period 1994 to 2012 is up to 0.84, which far exceeds the skill level of contemporary climate models.

  7. Interaction of mid-latitude air masses with the polar dome area during RACEPAC and NETCARE

    NASA Astrophysics Data System (ADS)

    Bozem, Heiko; Hoor, Peter; Koellner, Franziska; Kunkel, Daniel; Schneider, Johannes; Schulz, Christiane; Herber, Andreas; Borrmann, Stephan; Wendisch, Manfred; Ehrlich, Andre; Leaitch, Richard; Willis, Megan; Burkart, Julia; Thomas, Jennie; Abbatt, Jon

    2016-04-01

    We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories as well as Flexpart particle dispersion modeling we analyze the transport regimes of mid-latitude air masses traveling to the high Arctic prevalent during spring (RACEPAC 2014, NETCARE 2015) and summer (NETCARE 2014). In general more northern parts of the high Arctic (Lat > 75°N) were relatively unaffected from mid-latitude air masses. In contrast, regions further south are influenced by air masses from Asia and Russia (eastern part of Canadian Arctic and European Arctic) as well as from North America (central and western parts of Canadian Arctic). The transition between the mostly isolated high Arctic and more southern regions indicated by tracer gradients is remarkably sharp. This allows for a chemical definition of the Polar dome based on the variability of CO and CO2 as a marker. Isentropic surfaces that slope from the surface to higher altitudes in the high Arctic form the polar dome that represents a transport barrier for mid-latitude air masses to enter the lower troposphere in the high Arctic. Synoptic-scale weather systems frequently disturb this transport barrier and foster the exchange between air masses from the mid-latitudes and polar regions. This can finally lead to enhanced pollution levels in the lower polar troposphere. Mid-latitude pollution plumes from biomass burning or flaring entering the polar dome area lead to an enhancement of 30% of the observed CO mixing ratio within the polar dome area.

  8. Is air pollution a risk factor for rheumatoid arthritis?

    PubMed

    Essouma, Mickael; Noubiap, Jean Jacques N

    2015-01-01

    Rheumatoid arthritis is a chronic inflammatory debilitating disease triggered by a complex interaction involving genetic and environmental factors. Active smoking and occupational exposures such as silica increase its risk, suggesting that initial inflammation and generation of rheumatoid arthritis-related autoantibodies in the lungs may precede the clinical disease. This hypothesis paved the way to epidemiological studies investigating air pollution as a potential determinant of rheumatoid arthritis. Studies designed for epidemiology of rheumatoid arthritis found a link between traffic, a surrogate of air pollution, and this disease. Furthermore, a small case-control study recently found an association between wood smoke exposure and anticyclic citrullinated protein/peptide antibody in sera of patients presenting wood-smoke-related chronic obstructive pulmonary disease. However, reports addressing impact of specific pollutants on rheumatoid arthritis incidence and severity across populations are somewhat conflicting. In addition to the link reported between other systemic autoimmune rheumatic diseases and particulate matters/gaseous pollutants, experimental observation of exacerbated rheumatoid arthritis incidence and severity in mice models of collagen-induced arthritis after diesel exhaust particles exposure as well as hypovitaminosis D-related autoimmunity can help understand the role of air pollution in rheumatoid arthritis. All these considerations highlight the necessity to extend high quality epidemiological researches investigating different sources of atmospheric pollution across populations and particularly in low-and-middle countries, in order to further explore the biological plausibility of air pollution's effect in the pathogenesis of rheumatoid arthritis. This should be attempted to better inform policies aiming to reduce the burden of rheumatoid arthritis.

  9. Total-reflection X-ray fluorescence — a tool to obtain information about different air masses and air pollution

    NASA Astrophysics Data System (ADS)

    Schmeling, Martina

    2001-11-01

    Atmospheric aerosols are solid particles dissolved in air and change their chemical composition frequently depending on various parameters. In order to identify regional air circulation atmospheric aerosol filter samples were taken at Loyola University Chicago's Lake Shore Campus during the months of July and August 2000 with sampling times ranging between 1 and 2 h. The samples were digested in a microwave oven and analyzed by total-reflection X-ray fluorescence (TXRF) spectrometry. One diurnal variation comprising five consecutive sampling events was selected and discussed as well as 4 days experiencing different meteorology were compared to exemplify the variation in trace elemental concentration according to air mass movements and highlight the capability of total-reflection X-ray fluorescence analysis. It was found that due to changes in meteorological conditions particularly wind direction and wind speed, trace elemental compositions varied rapidly and could be used to distinguish between 'Lake Michigan air' and 'metropolitan Chicago air' on such short-term time scale like one hour. Back trajectory analysis was applied to support and corroborate the results. The outcome of this study clearly shows that total-reflection X-ray fluorescence is an optimal tool for analysis of atmospheric aerosols.

  10. The Use of Red Green Blue (RGB) Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Zavodsky, Bradley; Molthan, Andrew; Jedlovec, Gary

    2013-01-01

    AIRS ozone and model PV analysis confirm the stratospheric air in RGB Air Mass imagery. Trajectories confirm winds south of the low were distinct from CCB driven winds. Cross sections connect the tropopause fold, downward motion, and high nearsurface winds. Comparison to conceptual models show Shapiro-Keyser features and sting jet characteristics were observed in a storm that impacted the U.S. East Coast. RGB Air Mass imagery can be used to identify stratospheric air and regions susceptible to tropopause folding and attendant non-convective winds.

  11. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Ceburnis, D.; Martucci, G.; Bialek, J.; Dupuy, R.; Jennings, S. G.; Berresheim, H.; Wenger, J. C.; Sodeau, J. R.; Healy, R. M.; Facchini, M. C.; Rinaldi, M.; Giulianelli, L.; Finessi, E.; Worsnop, D.; O'Dowd, C. D.

    2009-12-01

    As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the NE Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm-3, while background marine air aerosol concentrations were between 400-600 cm-3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm-3, was observed and attributed to open ocean particle formation. Black carbon concentrations in polluted air were between 300-400 ng m-3, and in clean marine air were less than 50 ng m-3. Continental air submicron chemical composition (excluding refractory sea salt) was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF) and cloud condensation nuclei (CCN) to total condensation nuclei (CN) concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40-50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water

  12. Technical note: Air compared to nitrogen as nebulizing and drying gases for electrospray ionization mass spectrometry.

    PubMed

    Mielczarek, P; Silberring, J; Smoluch, M

    2016-01-01

    In the present study we tested the application of compressed air instead of pure nitrogen as the nebulizing and drying gas, and its influence on the quality of electrospray ionization (ESI) mass spectra. The intensities of the signals corresponding to protonated molecules were significantly (twice) higher when air was used. Inspection of signal-to-noise (S/N) ratios revealed that, in both cases, sensitivity was comparable. A higher ion abundance after the application of compressed air was followed by a higher background. Another potential risk of using air in the ESI source is the possibility for sample oxidation due to the presence of oxygen. To test this, we selected five easily oxidizing compounds to verify their susceptibility to oxidation. In particular, the presence of methionine was of interest. For all the compounds studied, no oxidation was observed. Amodiaquine oxidizes spontaneously in water solutions and its oxidized form can be detected a few hours after preparation. Direct comparison of the spectra where nitrogen was used with the corresponding spectra obtained when air was applied did not show significant differences. The only distinction was slightly different patterns of adducts when air was used. The difference concerns acetonitrile, which forms higher signals when air is the nebulizing gas. It is also important that the replacement of nitrogen with air does not affect quantitative data. The prepared calibration curves also visualize an intensity twice as high (independent of concentration within tested range) of the signal where air was applied. We have used our system continuously for three months with air as the nebulizing and drying gas and have not noticed any unexpected signal deterioration caused by additional source contamination from the air. Moreover, compressed air is much cheaper and easily available using oil-free compressors or pumps.

  13. Improvement of modal scaling factors using mass additive technique

    NASA Technical Reports Server (NTRS)

    Zhang, Qiang; Allemang, Randall J.; Wei, Max L.; Brown, David L.

    1987-01-01

    A general investigation into the improvement of modal scaling factors of an experimental modal model using additive technique is discussed. Data base required by the proposed method consists of an experimental modal model (a set of complex eigenvalues and eigenvectors) of the original structure and a corresponding set of complex eigenvalues of the mass-added structure. Three analytical methods,i.e., first order and second order perturbation methods, and local eigenvalue modification technique, are proposed to predict the improved modal scaling factors. Difficulties encountered in scaling closely spaced modes are discussed. Methods to compute the necessary rotational modal vectors at the mass additive points are also proposed to increase the accuracy of the analytical prediction.

  14. Elemental composition and radical formation potency of PM10 at an urban background station in Germany in relation to origin of air masses

    NASA Astrophysics Data System (ADS)

    Hellack, Bryan; Quass, Ulrich; Beuck, Henning; Wick, Gabriele; Kuttler, Wilhelm; Schins, Roel P. F.; Kuhlbusch, Thomas A. J.

    2015-03-01

    At an urban background station in Mülheim-Styrum, North Rhine Westphalia, Germany, a set of 75 PM10 samples was collected over a one year period, followed by analyses for mass, chemical composition and hydroxyl radical (OHrad) formation potency. Additionally, the origin of air masses for the sampling days was calculated by 48-h backward trajectories, subdivided into the four cardinal sectors. Significant lower PM10 mass concentrations were observed for summertime air masses from the west compared to the other seasons and cardinal sectors. For the OHrad formation potency higher values were detected if air masses originate from east and south, thus predominantly being of continental origin. From the elevated OHrad formation potencies in fall and winter a seasonal trend with low potencies in summers is assumed. Furthermore, source apportionment was performed by a positive matrix factor analysis, separating seven plausible factors which could be attributed to mineral dust, secondary nitrate, industry, non-exhaust traffic, fossil fuel combustion, marine aerosol and secondary aerosol factors. The intrinsic OHrad formation potency was found to be associated mainly with the fossil fuel combustion factor (45%) and industry factor (22%).

  15. Remote mass spectrometric sampling of electrospray- and desorption electrospray-generated ions using an air ejector.

    PubMed

    Dixon, R Brent; Bereman, Michael S; Muddiman, David C; Hawkridge, Adam M

    2007-10-01

    A commercial air ejector was coupled to an electrospray ionization linear ion trap mass spectrometer (LTQ) to transport remotely generated ions from both electrospray (ESI) and desorption electrospray ionization (DESI) sources. We demonstrate the remote analysis of a series of analyte ions that range from small molecules and polymers to polypeptides using the AE-LTQ interface. The details of the ESI-AE-LTQ and DESI-AE-LTQ experimental configurations are described and preliminary mass spectrometric data are presented.

  16. Detection of Hydrazine in Air Using Electron Transfer Ionization Mass Spectrometry.

    DTIC Science & Technology

    1981-02-15

    is in tI qualitative agreement with American Petroleum Institute (API) 6 data. Unequivocal identification and monitoring of N2H4 fuels at the launch...N2H4 in air. At even lower concentrations, the delay time 61ndex of Mass Spectral Data, American Petroleum Institute , Research Project 44, NBS

  17. Toward a better understanding of the impact of mass transit air pollutants on human health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern mass transit systems, based on roads, rail, water, and air, generate toxic airborne pollutants throughout the developed world. This has become one of the leading concerns about the use of modern transportation, particularly in densely-populated urban areas where their use is enormous and inc...

  18. Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters

    SciTech Connect

    Gupta, A.; Biswas, P. ); Monson, P.R. ); Novick, V.J. )

    1993-07-01

    The effect of humidity, particle hygroscopicity, and size on the mass loading capacity of glass fiber high efficiency particulate air filters was studied. Above the deliquescent point, the pressure drop across the filter increased nonlinearly with areal loading density (mass collected/filtration area) of a NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or nonhygroscopic particle mass loadings. The specific cake resistance K[sub 2] was computed for different test conditions and used as a measure of the mass loading capacity. K[sub 2] was found to decrease with increasing humidity for nonhygroscopic aluminum oxide particles and for hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K[sub 2] for lognormally distributed aerosols (parameters obtained from impactor data) was derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the nonhygroscopic aluminum oxide, the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor. 17 refs., 6 figs., 3 tabs.

  19. Matrix Factorization Techniques for Analysis of Imaging Mass Spectrometry Data

    PubMed Central

    Siy, Peter W.; Moffitt, Richard A.; Parry, R. Mitchell; Chen, Yanfeng; Liu, Ying; Sullards, M. Cameron; Merrill, Alfred H.; Wang, May D.

    2016-01-01

    Imaging mass spectrometry is a method for understanding the molecular distribution in a two-dimensional sample. This method is effective for a wide range of molecules, but generates a large amount of data. It is difficult to extract important information from these large datasets manually and automated methods for discovering important spatial and spectral features are needed. Independent component analysis and non-negative matrix factorization are explained and explored as tools for identifying underlying factors in the data. These techniques are compared and contrasted with principle component analysis, the more standard analysis tool. Independent component analysis and non-negative matrix factorization are found to be more effective analysis methods. A mouse cerebellum dataset is used for testing.

  20. Low-CCN concentration air masses over the eastern North Atlantic: Seasonality, meteorology, and drivers

    NASA Astrophysics Data System (ADS)

    Wood, Robert; Stemmler, Jayson D.; Rémillard, Jasmine; Jefferson, Anne

    2017-01-01

    A 20 month cloud condensation nucleus concentration (NCCN) data set from Graciosa Island (39°N, 28°W) in the remote North Atlantic is used to characterize air masses with low cloud condensation nuclei (CCN) concentrations. Low-CCN events are defined as 6 h periods with mean NCCN<20 cm-3 (0.1% supersaturation). A total of 47 low-CCN events are identified. Surface, satellite, and reanalysis data are used to explore the meteorological and cloud context for low-CCN air masses. Low-CCN events occur in all seasons, but their frequency was 3 times higher in December-May than during June-November. Composites show that many of the low-CCN events had a common meteorological basis that involves southerly low-level flow and rather low wind speeds at Graciosa. Anomalously low pressure is situated to the west of Graciosa during these events, but back trajectories and lagged SLP composites indicate that low-CCN air masses often originate as cold air outbreaks to the north and west of Graciosa. Low-CCN events were associated with low cloud droplet concentrations (Nd) at Graciosa, but liquid water path (LWP) during low-CCN events was not systematically different from that at other times. Satellite Nd and LWP estimates from MODIS collocated with Lagrangian back trajectories show systematically lower Nd and higher LWP several days prior to arrival at Graciosa, consistent with the hypothesis that observed low-CCN air masses are often formed by coalescence scavenging in thick warm clouds, often in cold air outbreaks.

  1. Factors controlling air quality in different European subway systems.

    PubMed

    Martins, Vânia; Moreno, Teresa; Mendes, Luís; Eleftheriadis, Konstantinos; Diapouli, Evangelia; Alves, Célia A; Duarte, Márcio; de Miguel, Eladio; Capdevila, Marta; Querol, Xavier; Minguillón, María Cruz

    2016-04-01

    Sampling campaigns using the same equipment and methodology were conducted to assess and compare the air quality at three South European subway systems (Barcelona, Athens and Oporto), focusing on concentrations and chemical composition of PM2.5 on subway platforms, as well as PM2.5 concentrations inside trains. Experimental results showed that the mean PM2.5 concentrations widely varied among the European subway systems, and even among different platforms within the same underground system, which might be associated to distinct station and tunnel designs and ventilation systems. In all cases PM2.5 concentrations on the platforms were higher than those in the urban ambient air, evidencing that there is generation of PM2.5 associated with the subway systems operation. Subway PM2.5 consisted of elemental iron, total carbon, crustal matter, secondary inorganic compounds, insoluble sulphate, halite and trace elements. Of all metals, Fe was the most abundant, accounting for 29-43% of the total PM2.5 mass (41-61% if Fe2O3 is considered), indicating the existence of an Fe source in the subway system, which could have its origin in mechanical friction and wear processes between rails, wheels and brakes. The trace elements with the highest enrichment in the subway PM2.5 were Ba, Cu, Mn, Zn, Cr, Sb, Sr, Ni, Sn, Co, Zr and Mo. Similar PM2.5 diurnal trends were observed on platforms from different subway systems, with higher concentrations during subway operating hours than during the transport service interruption, and lower levels on weekends than on weekdays. PM2.5 concentrations depended largely on the operation and frequency of the trains and the ventilation system, and were lower inside the trains, when air conditioning system was operating properly, than on the platforms. However, the PM2.5 concentrations increased considerably when the train windows were open. The PM2.5 levels inside the trains decreased with the trains passage in aboveground sections.

  2. Airborne mass spectrometers: four decades of atmospheric and space research at the Air Force research laboratory.

    PubMed

    Viggiano, A A; Hunton, D E

    1999-11-01

    Mass spectrometry is a versatile research tool that has proved to be extremely useful for exploring the fundamental nature of the earth's atmosphere and ionosphere and in helping to solve operational problems facing the Air Force and the Department of Defense. In the past 40 years, our research group at the Air Force Research Laboratory has flown quadrupole mass spectrometers of many designs on nearly 100 sounding rockets, nine satellites, three Space Shuttles and many missions of high-altitude research aircraft and balloons. We have also used our instruments in ground-based investigations of rocket and jet engine exhaust, combustion chemistry and microwave breakdown chemistry. This paper is a review of the instrumentation and techniques needed for space research, a summary of the results from many of the experiments, and an introduction to the broad field of atmospheric and space mass spectrometry in general.

  3. Turbulent heat and mass transfers across a thermally stratified air-water interface

    NASA Technical Reports Server (NTRS)

    Papadimitrakis, Y. A.; Hsu, Y.-H. L.; Wu, J.

    1986-01-01

    Rates of heat and mass transfer across an air-water interface were measured in a wind-wave research facility, under various wind and thermal stability conditions (unless otherwise noted, mass refers to water vapor). Heat fluxes were obtained from both the eddy correlation and the profile method, under unstable, neutral, and stable conditions. Mass fluxes were obtained only under unstable stratification from the profile and global method. Under unstable conditions the turbulent Prandtl and Schmidt numbers remain fairly constant and equal to 0.74, whereas the rate of mass transfer varies linearly with bulk Richardson number. Under stable conditions the turbulent Prandtl number rises steadily to a value of 1.4 for a bulk Richardson number of about 0.016. Results of heat and mass transfer, expressed in the form of bulk aerodynamic coefficients with friction velocity as a parameter, are also compared with field data.

  4. Measuring Air-water Interfacial Area for Soils Using the Mass Balance Surfactant-tracer Method

    PubMed Central

    Araujo, Juliana B.; Mainhagu, Jon; Brusseau, Mark L.

    2015-01-01

    There are several methods for conducting interfacial partitioning tracer tests to measure air-water interfacial area in porous media. One such approach is the mass balance surfactant tracer method. An advantage of the mass-balance method compared to other tracer-based methods is that a single test can produce multiple interfacial area measurements over a wide range of water saturations. The mass-balance method has been used to date only for glass beads or treated quartz sand. The purpose of this research is to investigate the effectiveness and implementability of the mass-balance method for application to more complex porous media. The results indicate that interfacial areas measured with the mass-balance method are consistent with values obtained with the miscible-displacement method. This includes results for a soil, for which solid-phase adsorption was a significant component of total tracer retention. PMID:25950136

  5. Isolation and mass spectrometry of transcription factor complexes.

    PubMed

    Sebastiaan Winkler, G; Lacomis, Lynne; Philip, John; Erdjument-Bromage, Hediye; Svejstrup, Jesper Q; Tempst, Paul

    2002-03-01

    Protocols are described that enable the isolation of novel proteins associated with a known protein and the subsequent identification of these proteins by mass spectrometry. We review the basics of nanosample handling and of two complementary approaches to mass analysis, and provide protocols for the entire process. The protein isolation procedure is rapid and based on two high-affinity chromatography steps. The method does not require previous knowledge of complex composition or activity and permits subsequent biochemical characterization of the isolated factor. As an example, we provide the procedures used to isolate and analyze yeast Elongator, a histone acetyltransferase complex important for transcript elongation, which led to the identification of three novel subunits.

  6. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Ceburnis, D.; Martucci, G.; Bialek, J.; Dupuy, R.; Jennings, S. G.; Berresheim, H.; Wenger, J.; Healy, R.; Facchini, M. C.; Rinaldi, M.; Giulianelli, L.; Finessi, E.; Worsnop, D.; Ehn, M.; Mikkilä, J.; Kulmala, M.; O'Dowd, C. D.

    2010-09-01

    As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June, 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the N. E. Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm-3, while background marine air aerosol concentrations were between 400-600 cm-3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm-3, was observed and attributed to open ocean particle formation. Continental air submicron chemical composition (excluding refractory sea salt) was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF) and cloud condensation nuclei (CCN) to total condensation nuclei (CN) concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40-50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water soluble organic carbon, which, in turn, was dominated by methanesulphonic acid (MSA). Sulphate concentrations were

  7. Establishing Lagrangian Connections between Observations within Air Masses Crossing the Atlantic during the ICARTT Experiment

    NASA Technical Reports Server (NTRS)

    Methven, J.; Arnold, S. R.; Stohl, A.; Evans, M. J.; Avery, M.; Law, K.; Lewis, A. C.; Monks, P. S.; Parrish, D.; Reeves, C.; Schlager, H.; Atlas, E.; Blake, D.; Coe, H.; Cohen, R. C.; Crosier, J.; Flocke, F.; Holloway, J. S.; Hopkins, J. R.; Huber, G.; McQuaid, J.; Purvis, R.; Rappengluck, B.; Ryerson, T. B.; Sachse, G. W.

    2006-01-01

    The International Consortium for Atmospheric Research on Transport and Transformation (ICARTT)-Lagrangian experiment was conceived with an aim to quantify the effects of photochemistry and mixing on the transformation of air masses in the free troposphere away from emissions. To this end attempts were made to intercept and sample air masses several times during their journey across the North Atlantic using four aircraft based in New Hampshire (USA), Faial (Azores) and Creil (France). This article begins by describing forecasts using two Lagrangian models that were used to direct the aircraft into target air masses. A novel technique is then used to identify Lagrangian matches between flight segments. Two independent searches are conducted: for Lagrangian model matches and for pairs of whole air samples with matching hydrocarbon fingerprints. The information is filtered further by searching for matching hydrocarbon samples that are linked by matching trajectories. The quality of these coincident matches is assessed using temperature, humidity and tracer observations. The technique pulls out five clear Lagrangian cases covering a variety of situations and these are examined in detail. The matching trajectories and hydrocarbon fingerprints are shown and the downwind minus upwind differences in tracers are discussed.

  8. MISR Aerosol Air Mass Type Mapping over Mega-City: Validation and Applications

    NASA Astrophysics Data System (ADS)

    Patadia, F.; Kahn, R. A.

    2010-12-01

    Most aerosol air-quality monitoring in mega-city environments is done from scattered ground stations having detailed chemical and optical sampling capabilities. Satellite instruments such as the Multi-angle Imaging SpectroRadiometer (MISR) can retrieve total-column Aerosol Optical Depth (AOD), along with some information about particle microphysical properties. Although the particle property information from MISR is much less detailed than that obtained from the ground sampling stations, the coverage is extensive, making it possible to put individual surface observations into the context of regional aerosol air mass types. This paper presents an analysis of MISR aerosol observations made coincident with aircraft and ground-based instruments during the INTEX-B field campaign. These detailed comparisons of satellite aerosol property retrievals against dedicated field measurements provide the opportunity to validate the retrievals quantitatively at a regional level, and help to improve aerosol representation in retrieval algorithms. Validation of MISR retrieved AOD and other aerosol properties over the INTEX-B study region in and around Mexico City will be presented. MISR’s ability to distinguish among aerosol air mass types will be discussed. The goal of this effort is to use the MISR aerosol property retrievals for mapping both aerosol air mass type and AOD gradients in mega-city environments over the decade-plus that MISR has made global observations.

  9. Drug confirmation by mass spectrometry: Identification criteria and complicating factors.

    PubMed

    Yuan, Chao; Chen, Derrick; Wang, Sihe

    2015-01-01

    Drug confirmation by mass spectrometry coupled with chromatography is essential to toxicology, doping control, pain management, and workplace drug testing. High confidence in this technology is due to its superior specificity and sensitivity. However, there are challenges associated with drug confirmation, and proper setup and validation of these assays are important in assuring high-quality results. In this article, assay parameters required for drug confirmation are summarized based on recent scientific publications, various established guidelines, and our own practical experience. Factors affecting the result quality and correct results interpretation are critically reviewed. Several emerging technologies and their potential applications are briefly explored.

  10. Stable isotope composition of waters in the Great Basin, United States 1. Air-mass trajectories

    USGS Publications Warehouse

    Friedman, I.; Harris, J.M.; Smith, G.I.; Johnson, C.A.

    2002-01-01

    Isentropic trajectories, calculated using the NOAA/Climate Monitoring and Diagnostics Laboratory's isentropic transport model, were used to determine air-parcel origins and the influence of air mass trajectories on the isotopic composition of precipitation events that occurred between October 1991 and September 1993 at Cedar City, Utah, and Winnemucca, Nevada. Examination of trajectories that trace the position of air parcels backward in time for 10 days indicated five distinct regions of water vapor origin: (1) Gulf of Alaska and North Pacific, (2) central Pacific, (3) tropical Pacific, (4) Gulf of Mexico, and (5) continental land mass. Deuterium (??D) and oxygen-18 (??18O) analyses were made of precipitation representing 99% of all Cedar City events. Similar analyses were made on precipitation representing 66% of the precipitation falling at Winnemucca during the same period. The average isotopic composition of precipitation derived from each water vapor source was determined. More than half of the precipitation that fell at both sites during the study period originated in the tropical Pacific and traveled northeast to the Great Basin; only a small proportion traversed the Sierra Nevada. The isotopic composition of precipitation is determined by air-mass origin and its track to the collection station, mechanism of droplet formation, reequilibration within clouds, and evaporation during its passage from cloud to ground. The Rayleigh distillation model can explain the changes in isotopic composition of precipitation as an air mass is cooled pseudo-adiabatically during uplift. However, the complicated processes that take place in the rapidly convecting environment of cumulonimbus and other clouds that are common in the Great Basin, especially in summer, require modification of this model because raindrops that form in the lower portion of those clouds undergo isotopic change as they are elevated to upper levels of the clouds from where they eventually drop to the

  11. Source areas and trajectories of nucleating air masses within and near the Carpathian Basin

    NASA Astrophysics Data System (ADS)

    Németh, Z.; Salma, I.

    2014-04-01

    Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6-1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeast Central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28+6/-4) % and (27+9/-4) %, respectively. Total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate if there are any specific tracks and/or separable source regions for the nucleating air masses within or near the basin. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation, and end time parameter of the particle growth were derived by a standardized procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each air mass trajectory that is associated with the track of the nucleating air mass. The results indicated that the nucleation events happened in the continental boundary layer mostly within the Carpathian Basin but the most distant trajectories originated outside of the basin. The tracks of the nucleating air masses were predominantly associated with NW and SE geographical fields, while the source areas that could be separated were frequently situated in the NW and NE quarters. Many of them were within or close to large forested territories. The results also emphasize that the new particle formation and growth phenomenon that occurs in the region influences larger territories than the Carpathian Basin.

  12. Seasonal air and water mass redistribution effects on LAGEOS and Starlette

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roberto; Wilson, Clark R.

    1987-01-01

    Zonal geopotential coefficients have been computed from average seasonal variations in global air and water mass distribution. These coefficients are used to predict the seasonal variations of LAGEOS' and Starlette's orbital node, the node residual, and the seasonal variation in the 3rd degree zonal coefficient for Starlette. A comparison of these predictions with the observed values indicates that air pressure and, to a lesser extent, water storage may be responsible for a large portion of the currently unmodeled variation in the earth's gravity field.

  13. Particulate Air Pollution and Clinical Cardiovascular Disease Risk Factors

    PubMed Central

    Shanley, Ryan P; Hayes, Richard B; Cromar, Kevin R; Ito, Kazuhiko; Gordon, Terry; Ahn, Jiyoung

    2016-01-01

    BACKGROUND Long-term exposure to ambient particulate matter (PM) air pollution is associated with increased cardiovascular disease (CVD); however, the impact of PM on clinical risk factors for CVD in healthy subjects is unclear. We examined the relationship of PM with levels of circulating lipids and blood pressure in the Third National Health and Nutrition Examination Survey (NHANES III), a large nationally-representative US survey. METHODS This study was based on 11,623 adult participants of NHANES III (1988–1994; median age 41.0). Serum lipids and blood pressure were measured during the NHANES III examination. Average exposure for 1988–1994 to particulate matter <10µm in aerodynamic diameter (PM10) at the residences of participants was estimated based on measurements from U.S. Environmental Protection Agency monitors. Multivariate linear regression was used to estimate the associations of PM10 with lipids and blood pressure. RESULTS An interquartile range width (IQRw) increase in PM10 exposure (11.1 µg/m3) in the study population was associated with 2.42 percent greater serum triglycerides (95% confidence interval [CI]: 1.09–3.76); multivariate adjusted means of triglycerides according to increasing quartiles of PM10 were 137.6, 142.5, 142.6, and 148.9 mg/dL, respectively. An IQRw increase in PM10 was associated with 1.43 percent greater total cholesterol (95% CI: 1.21–1.66). These relationships with triglycerides and total cholesterol did not differ by age or region. Associations of PM10 with blood pressure were modest. CONCLUSIONS Findings from this large diverse study indicate that greater long-term PM10 exposure is associated with elevated serum triglycerides and total cholesterol, potentially mediating air pollution-related effects on CVD. PMID:26605815

  14. Improving Hydrological Models by Applying Air Mass Boundary Identification in a Precipitation Phase Determination Scheme

    NASA Astrophysics Data System (ADS)

    Feiccabrino, James; Lundberg, Angela; Sandström, Nils

    2013-04-01

    Many hydrological models determine precipitation phase using surface weather station data. However, there are a declining number of augmented weather stations reporting manually observed precipitation phases, and a large number of automated observing systems (AOS) which do not report precipitation phase. Automated precipitation phase determination suffers from low accuracy in the precipitation phase transition zone (PPTZ), i.e. temperature range -1° C to 5° C where rain, snow and mixed precipitation is possible. Therefore, it is valuable to revisit surface based precipitation phase determination schemes (PPDS) while manual verification is still widely available. Hydrological and meteorological approaches to PPDS are vastly different. Most hydrological models apply surface meteorological data into one of two main PPDS approaches. The first is a single rain/snow threshold temperature (TRS), the second uses a formula to describe how mixed precipitation phase changes between the threshold temperatures TS (below this temperature all precipitation is considered snow) and TR (above this temperature all precipitation is considered rain). However, both approaches ignore the effect of lower tropospheric conditions on surface precipitation phase. An alternative could be to apply a meteorological approach in a hydrological model. Many meteorological approaches rely on weather balloon data to determine initial precipitation phase, and latent heat transfer for the melting or freezing of precipitation falling through the lower troposphere. These approaches can improve hydrological PPDS, but would require additional input data. Therefore, it would be beneficial to link expected lower tropospheric conditions to AOS data already used by the model. In a single air mass, rising air can be assumed to cool at a steady rate due to a decrease in atmospheric pressure. When two air masses meet, warm air is forced to ascend the more dense cold air. This causes a thin sharp warming (frontal

  15. Stability of reference masses: VII. Cleaning methods in air and vacuum applied to a platinum mass standard similar to the international and national kilogram prototypes

    NASA Astrophysics Data System (ADS)

    Cumpson, Peter J.; Sano, Naoko; Barlow, Anders J.; Portoles, Jose F.

    2013-10-01

    Mercury contamination and the build-up of carbonaceous contamination are two contributing factors to the instability observed in kilogram prototype masses. The kilogram prototypes that lie at the core of the dissemination of the SI base unit were manufactured in the late 19th century, and have polished surfaces. In papers IV and V of this series we developed a method for cleaning noble metal mass standards in air to remove carbonaceous contamination. At the core of this ‘UVOPS’ protocol is the application of UV light and ozone gas generated in situ in air. The precise nature of the carbonaceous contamination that builds up on such surfaces is difficult to mimic demonstrably or quickly on new test surfaces, yet data from such tests are needed to provide the final confidence to allow UVOPS to be applied to a real 19th century kilogram prototype. Therefore, in the present work we have applied the UVOPS method to clean a platinum avoirdupois pound mass standard, ‘RS2’, manufactured in the mid-19th century. This is thought to have been polished in a similar manner to the kilogram prototypes. To our knowledge this platinum surface has not previously been cleaned by any method. We used x-ray photoelectron spectroscopy to identify organic contamination, and weighing to quantify the mass lost at each application of the UVOPS procedure. The UVOPS procedure is shown to be very effective. It is likely that the redefinition of the kilogram will require mass comparisons in vacuum in the years to come. Therefore, in addition to UVOPS a cleaning method for use in vacuum will also be needed. We introduce and evaluate gas cluster ion-beam (GCIB) treatment as a potential method for cleaning reference masses in vacuum. Again, application of this GCIB cleaning to a real artefact, RS2, allows us to make a realistic evaluation of its performance. While it has some attractive features, we cannot recommend it for cleaning mass standards in its present form.

  16. 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 ...

  17. Mixing of stratospheric and tropospheric air-masses detected with CRISTA-NF during AMMA

    NASA Astrophysics Data System (ADS)

    Weigel, K.; Guenther, G.; Hoffmann, L.; Konopka, P.; Riese, M.

    2009-04-01

    CRISTA-NF (CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere - New Frontiers) is an infrared limb sounding instrument installed onbord the high-flying research aircraft M55-Geophysica and took part in the AMMA-SCOUT measurement campaign in Summer 2006. During the test flight on 29th of July 2006, CRISTA-NF detected a sharp boundary between ozone rich air over northernItaly and ozone poor air over southern Italy and the Mediterranean Sea. The structure is also clearly visible in the HNO3 distribution. The air mass boundary extends from about 10km altitude to the thermal tropopause at about 16km altitude with indication for mixing in the lower part of this altitude range. This is supported by enhanced values of PAN and water vapour found. The observed structure is also visible in the CLaMS (Chemical Lagrangian Model of the Stratosphere) ozone distribution but hardly resolved in ECMWF forecast data. Backward trajectories show that the ozone rich air is originated westwards, between 40 and 60oN while the ozone poor air is coming from the south-east, at about 0-20oN and has a younger age of air. In the presentation details of the CRISTA-NF measurements and retrieval procedures as well as the origin of the trace gas structures will be discussed.

  18. Factors that influence the tribocharging of pulverulent materials in compressed-air devices

    NASA Astrophysics Data System (ADS)

    Das, S.; Medles, K.; Mihalcioiu, A.; Beleca, R.; Dragan, C.; Dascalescu, L.

    2008-12-01

    Tribocharging of pulverulent materials in compressed-air devices is a typical multi-factorial process. This paper aims at demonstrating the interest of using the design of experiments methodology in association with virtual instrumentation for quantifying the effects of various process varaibles and of their interactions, as a prerequisite for the development of new tribocharging devices for industrial applications. The study is focused on the tribocharging of PVC powders in compressed-air devices similar to those employed in electrostatic painting. A classical 2 full-factorial design (3 factors at two levels) was employed for conducting the experiments. The response function was the charge/mass ratio of the material collected in a modified Faraday cage, at the exit of the tribocharging device. The charge/mass ratio was found to increase with the injection pressure and the vortex pressure in the tribocharging device, and to decrease with the increasing of the feed rate. In the present study an in-house design of experiments software was employed for statistical analysis of experimental data and validation of the experimental model.

  19. Overview of aerosol properties associated with air masses sampled by the ATR-42 during the EUCAARI campaign (2008)

    NASA Astrophysics Data System (ADS)

    Crumeyrolle, S.; Schwarzenboeck, A.; Sellegri, K.; Burkhart, J. F.; Stohl, A.; Gomes, L.; Quennehen, B.; Roberts, G.; Weigel, R.; Roger, J. C.; Villani, P.; Pichon, J. M.; Bourrianne, T.; Laj, P.

    2012-04-01

    Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) project the Météo-France aircraft ATR-42 performed 22 research flights, over central Europe and the North Sea during the intensive observation period in May 2008. For the campaign, the ATR-42 was equipped in order to study aerosol physical, chemical and optical properties, as well as cloud microphysics. During the campaign, continental air masses from Eastern and Western Europe were encountered, along with polar and Scandinavian air masses. For the 22 research flights, retroplume analyses along the flight tracks were performed with FLEXPART in order to classify air masses into five sectors of origin which allows for a qualitative evaluation of emission influence on the respective air parcel. In the polluted boundary layer (BL), typical concentrations of particles with diameters larger than 10 nm (N10) are of the order of 5000-6000 cm-3, whereas N10 concentrations of clean air masses were lower than 1300 cm-3. The detection of the largest particle number concentrations occurred in air masses coming from Polar and Scandinavian regions for which an elevated number of nucleation mode (25-28 nm) particles was observed and attributed to new particle formation over open sea. In the free troposphere (FT), typical observed N10 are of the order of 900 cm-3 in polluted air masses and 400-600 cm-3 in clean air masses, respectively. In both layers, the chemical composition of submicron aerosol particles is dominated by organic matter and nitrate in polluted air masses, while, sulphate and ammonium followed by organics dominate the submicron aerosols in clean air masses. The highest CCN/CN ratios were observed within the polar air masses while the CCN concentration values are the highest within the polluted air masses. Within the five air mass sectors defined and the two layers (BL and FT), observations have been distinguished into anticyclonic (first half of May 2008) and cyclonic

  20. Ozone and Trace Gas Trends in the UK and Links to Changing Air Mass Pathways

    NASA Astrophysics Data System (ADS)

    Fleming, Z.; Monks, P. S.; Reeves, C.; Bohnenstengel, S.

    2014-12-01

    Trace gas measurements from UK measurement sites on the North Sea coast and in central London reveal a complicated relationship between NO2, CO, hydrocarbons and ozone. Due to the location of the sites, they receive air masses from the UK, Europe, the North sea, Scandinavia and the Arctic and Atlantic Seas and any seasonality is hard to discern. The transport pathway of air masses that can change on an hourly timescale clearly influences the trace gas levels. Investigations into how the transport pathways have changed over the years, using the NAME dispersion model try to elucidate whether it is the 'where' (transport pathway) or the 'what' (trace gas emissions) that is leading to the ozone trends recorded over the past few years.

  1. Toward a better understanding of the impact of mass transit air pollutants on human health.

    PubMed

    Kim, Ki-Hyun; Kumar, Pawan; Szulejko, Jan E; Adelodun, Adedeji A; Junaid, Muhammad Faisal; Uchimiya, Minori; Chambers, Scott

    2017-05-01

    Globally, modern mass transport systems whether by road, rail, water, or air generate airborne pollutants in both developing and developed nations. Air pollution is the primary human health concern originating from modern transportation, particularly in densely-populated urban areas. This review will specifically focus on the origin and the health impacts of carbonaceous traffic-related air pollutants (TRAP), including particulate matter (PM), volatile organic compounds (VOCs), and elemental carbon (EC). We conclude that the greatest current challenge regarding urban TRAP is understanding and evaluating the human health impacts well enough to set appropriate pollution control measures. Furthermore, we provide a detailed discussion regarding the effects of TRAP on local environments and pedestrian health in low and high traffic-density environments.

  2. Estimation of whole lemon mass transfer parameters during hot air drying using different modelling methods

    NASA Astrophysics Data System (ADS)

    Torki-Harchegani, Mehdi; Ghanbarian, Davoud; Sadeghi, Morteza

    2015-08-01

    To design new dryers or improve existing drying equipments, accurate values of mass transfer parameters is of great importance. In this study, an experimental and theoretical investigation of drying whole lemons was carried out. The whole lemons were dried in a convective hot air dryer at different air temperatures (50, 60 and 75 °C) and a constant air velocity (1 m s-1). In theoretical consideration, three moisture transfer models including Dincer and Dost model, Bi- G correlation approach and conventional solution of Fick's second law of diffusion were used to determine moisture transfer parameters and predict dimensionless moisture content curves. The predicted results were then compared with the experimental data and the higher degree of prediction accuracy was achieved by the Dincer and Dost model.

  3. Spatial variability of hailfalls in France: an analysis of air mass retro-trajectories

    NASA Astrophysics Data System (ADS)

    Hermida, Lucía; Merino, Andrés; Sánchez, José Luis; Berthet, Claude; Dessens, Jean; López, Laura; Fernández-González, Sergio; Gascón, Estíbaliz; García-Ortega, Eduardo

    2014-05-01

    Hail is the main meteorological risk in south-west France, with the strongest hailfalls being concentrated in just a few days. Specifically, this phenomenon occurs most often and with the greatest severity in the Midi-Pyrénées area. Previous studies have revealed the high spatial variability of hailfall in this part of France, even leading to different characteristics being recorded on hailpads that were relatively close together. For this reason, an analysis of the air mass trajectories was carried out at ground level and at altitude, which subsequently led to the formation of the hail recorded by these hailpads. It is already known that in the study zone, the trajectories of the storms usually stretch for long distances and are oriented towards the east, leading to hailstones with diameters in excess of 3 cm, and without any change in direction above 3 km. We analysed different days with hail precipitation where there was at least one stone with a diameter of 3 cm or larger. Using the simulations from these days, an analysis of the backward trajectories of the air masses was carried out. We used the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) to determine the origin of the air masses, and tracked them toward each of the hailpads that were hit during the day studied. The height of the final points was the height of the impacted hailpads. Similarly, the backward trajectories for different heights were also established. Finally, the results show how storms that affect neighbouring hailpads come from very different air masses; and provide a deeper understanding of the high variability that affects the characteristics of hailfalls. Acknowledgements The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2. This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22).

  4. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity.

    PubMed

    Bugbee, B; Monje, O; Tanner, B

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  5. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; Monje, O.; Tanner, B.

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  6. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways

    NASA Astrophysics Data System (ADS)

    Liu, D. X.; Liu, Z. C.; Chen, C.; Yang, A. J.; Li, D.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2016-04-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H+, nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2- and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios.

  7. Aqueous reactive species induced by a surface air discharge: Heterogeneous mass transfer and liquid chemistry pathways

    PubMed Central

    Liu, D. X.; Liu, Z. C.; Chen, C.; Yang, A. J.; Li, D.; Rong, M. Z.; Chen, H. L.; Kong, M. G.

    2016-01-01

    Plasma-liquid interaction is a critical area of plasma science and a knowledge bottleneck for many promising applications. In this paper, the interaction between a surface air discharge and its downstream sample of deionized water is studied with a system-level computational model, which has previously reached good agreement with experimental results. Our computational results reveal that the plasma-induced aqueous species are mainly H+, nitrate, nitrite, H2O2 and O3. In addition, various short-lived aqueous species are also induced, regardless whether they are generated in the gas phase first. The production/loss pathways for aqueous species are quantified for an air gap width ranging from 0.1 to 2 cm, of which heterogeneous mass transfer and liquid chemistry are found to play a dominant role. The short-lived reactive oxygen species (ROS) and reactive nitrogen species (RNS) are strongly coupled in liquid-phase reactions: NO3 is an important precursor for short-lived ROS, and in turn OH, O2− and HO2 play a crucial role for the production of short-lived RNS. Also, heterogeneous mass transfer depends strongly on the air gap width, resulting in two distinct scenarios separated by a critical air gap of 0.5 cm. The liquid chemistry is significantly different in these two scenarios. PMID:27033381

  8. Influence of drying air parameters on mass transfer characteristics of apple slices

    NASA Astrophysics Data System (ADS)

    Beigi, Mohsen

    2016-10-01

    To efficiently design both new drying process and equipment and/or to improve the existing systems, accurate values of mass transfer characteristics are necessary. The present study aimed to investigate the influence of drying air parameters (i.e. temperature, velocity and relative humidity) on effective diffusivity and convective mass transfer coefficient of apple slices. The Dincer and Dost model was used to determine the mass transfer characteristics. The obtained Biot number indicated that the moisture transfer in the apple slices was controlled by both internal and external resistance. The effective diffusivity and mass transfer coefficient values obtained to be in the ranges of 7.13 × 10-11-7.66 × 10-10 and 1.46 × 10-7-3.39 × 10-7 m s-1, respectively and the both of them increased with increasing drying air temperature and velocity, and decreasing relative humidity. The validation of the model showed that the model predicted the experimental drying curves of the samples with a good accuracy.

  9. Small-size mass spectrometer for determining gases and volatile compounds in air during breathing

    NASA Astrophysics Data System (ADS)

    Kogan, V. T.; Kozlenok, A. V.; Chichagov, Yu. V.; Antonov, A. S.; Lebedev, D. S.; Bogdanov, A. A.; Moroshkin, V. S.; Berezina, A. V.; Viktorova-Leclerc, O. S.; Vlasov, S. A.; Tubol'tsev, Yu. V.

    2015-10-01

    We describe an automated mass spectrometer for diagnostics of deceases from the composition of exhaled air. It includes a capillary system, which performs a rapid direct feeding of the sample to the instrument without changing substantially its composition and serves for studying the dynamics of variation of the ratio between various components of exhaled air. The membrane system for introducing the sample is intended for determining low concentrations of volatile organic compounds which are biomarkers of pathologies. It is characterized by selective transmittance and ensures the detection limits of target compounds at the parts per million-parts per billion (ppm-ppb) level. A static mass analyzer operating on permanent magnets possesses advantages important for mobile devices as compared to its dynamic analogs: it is more reliable in operation, has a larger dynamic range, and can be used for determining the concentration of components in the mixture one-by-one or simultaneously. The curvilinear output boundary of the magnetic lens of the mass analyzer makes it possible to reduce its weight and size by 2.5 times without deteriorating the mass resolution. We report on the results of testing of the instrument and consider the possibility of its application for early detection of deceases of respiratory and blood circulation system, gastrointestinal tract, and endocrine system.

  10. 76 FR 19913 - Compliance Testing Procedures: Correction Factor for Room Air Conditioners

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-11

    ... that as atmospheric pressure drops, so does the air density and, therefore, the mass of air in a room. As atmospheric pressure drops, the efficiency of a unit would also drop because there would be less... (Atmospheric Pressure Inputs). Condenser Inlet Pressure psia 14.695 14.204 13.713 13.222 12.731...

  11. Variability of aerosol, gaseous pollutants and meteorological characteristics associated with continental, urban and marine air masses at the SW Atlantic coast of Iberia

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

    2011-12-01

    air masses passing the continent the organic aerosol fraction dominated the total NR-PM1. For this reason, using Positive Matrix Factorization (PMF) four organic aerosol (OA) classes that can be associated with various aerosol sources and components were identified: a highly-oxygenated OA is the major component contributing an average of 43% of the particulate organic mass while the semi-volatile OA accounts for 23%. A hydrocarbon-like OA mainly resulting from industries, traffic and shipping emissions as well as particles from wood burning emissions also contribute to total OA dependent on the air mass origin. The variability of ozone is not only affected by different types of air masses but also significantly by the diurnal variation as a consequence of the solar radiation as well as local meteorological parameters.

  12. On the origin and destination of atmospheric moisture and air mass over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xu, Xiang-De; Yang, Shuai; Zhang, Wei

    2012-12-01

    The Tibet Plateau (TP) is a key region that imposes profound impacts on the atmospheric water cycle and energy budget of Asia, even the global climate. In this work, we develop a climatology of origin (destination) of air mass and moisture transported to (from) the TP using a Lagrangian moisture diagnosis combined with the forward and backward atmospheric tracking schemes. The climatology is derived from 6-h particle positions based on 5-year (2005-2009) seasonal summer trajectory dataset from the Lagrangian particle dispersion model FLEXPART using NCEP/GFS data as input, where the regional model atmosphere was globally filled with particles. The results show that (1) the dominant origin of the moisture supplied to the TP is a narrow tropical-subtropical band in the extended Arabian Sea covering a long distance from the Indian subcontinent to the Southern Hemisphere. Two additional moisture sources are located in the northwestern part of TP and the Bay of Bengal and play a secondary role. This result indicates that the moisture transporting to the TP more depends on the Indian summer monsoon controlled by large-scale circulation. (2) The moisture departing from the TP can be transported rapidly to East Asia, including East China, Korea, Japan, and even East Pacific. The qualitative similarity between the regions of diagnosed moisture loss and the pattern of the observed precipitation highlights the robustness of the role of the TP on precipitation over East Asia. (3) In contrast to the moisture origin confined in the low level, the origin and fate of whole column air mass over the TP is largely controlled by a strong high-level Asian anticyclone. The results show that the TP is a crossroad of air mass where air enters mainly from the northwest and northeast and continues in two separate streams: one goes southwestwards over the Indian Ocean and the other southeastwards through western North Pacific. Both of them partly enter the trade wind zone, which manifests the

  13. Influence of air mass origin on aerosol properties at a remote Michigan forest site

    NASA Astrophysics Data System (ADS)

    VanReken, T. M.; Mwaniki, G. R.; Wallace, H. W.; Pressley, S. N.; Erickson, M. H.; Jobson, B. T.; Lamb, B. K.

    2015-04-01

    The northern Great Lakes region of North America is a large, relatively pristine area. To date, there has only been limited study of the atmospheric aerosol in this region. During summer 2009, a detailed characterization of the atmospheric aerosol was conducted at the University of Michigan Biological Station (UMBS) as part of the Community Atmosphere-Biosphere Interactions Experiment (CABINEX). Measurements included particle size distribution, water-soluble composition, and CCN activity. Aerosol properties were strongly dependent on the origin of the air masses reaching the site. For ∼60% of the study period, air was transported from sparsely populated regions to the northwest. During these times aerosol loadings were low, with mean number and volume concentrations of 1630 cm-3 and 1.91 μm3 cm-3, respectively. The aerosol during clean periods was dominated by organics, and exhibited low hygroscopicities (mean κ = 0.18 at s = 0.3%). When air was from more populated regions to the east and south (∼29% of the time), aerosol properties reflected a stronger anthropogenic influence, with 85% greater particle number concentrations, 2.5 times greater aerosol volume, six times more sulfate mass, and increased hygroscopicity (mean k = 0.24 at s = 0.3%). These trends are have the potential to influence forest-atmosphere interactions and should be targeted for future study.

  14. Optimization of solar cells for air mass zero operation and a study of solar cells at high temperatures, phase 2

    NASA Technical Reports Server (NTRS)

    Hovel, H.; Woodall, J. M.

    1976-01-01

    Crystal growth procedures, fabrication techniques, and theoretical analysis were developed in order to make GaAlAs-GaAs solar cell structures which exhibit high performance at air mass 0 illumination and high temperature conditions.

  15. Calibration of Dissolved Noble Gas Mass Spectrometric Measurements by an Air-Water Equilibration System

    NASA Astrophysics Data System (ADS)

    Hillegonds, Darren; Matsumoto, Takuya; Jaklitsch, Manfred; Han, Liang-Feng; Klaus, Philipp; Wassenaar, Leonard; Aggarwal, Pradeep

    2013-04-01

    Precise measurements by mass spectrometry of dissolved noble gases (He, Ar, Ne, Kr, Xe) in water samples require careful calibration against laboratory standards with known concentrations. Currently, air pipettes are used for day-to-day calibrations, making estimation of overall analytical uncertainties for dissolved noble gas measurements in water difficult. Air equilibrated water (AEW) is often used as a matrix-equivalent laboratory standard for dissolved gases in groundwater, because of the well-known and constant fractions of noble gases in the atmosphere. AEW standards, however, are only useful if the temperature and pressure of the gas-water equilibrium can be controlled and measured precisely (i.e., to better than 0.5%); contamination and partial sample degassing must also be prevented during sampling. Here we present the details of a new custom air-water equilibration system which consists of an insulated 600 liter tank filled with deionized water, held isothermally at a precise target temperature (<0.05 °C) through the use of a heat exchanger. The temperature and total dissolved gas of the water in the tank are monitored continually, as are atmospheric pressure and air temperature in the laboratory. Different noble gas concentration standards can be reliably produced by accurately controlling the water temperature of the equilibration system. Equilibration characteristics and reproducibility of this system for production of copper tubes containing known amounts of noble gases will be presented.

  16. Determination of the effect of transfer between vacuum and air on mass standards of platinum-iridium and stainless steel

    NASA Astrophysics Data System (ADS)

    Davidson, Stuart

    2010-08-01

    This paper reports work undertaken to assess the change in the mass values of stainless steel and platinum-iridium weights transferred between air and vacuum and to determine the repeatability of this change. Sets of kilogram transfer standards, manufactured from stainless steel and platinum-iridium and with different surface areas, were used to determine the effect of transfer between air and vacuum on the values of the mass standards. The SI unit of mass is the only unit of the seven base SI quantities which is still defined in terms of an artefact rather than by relation to a fundamental physical constant. Work is underway to identify a means of deriving the SI unit of mass from fundamental constants and at present the two principal approaches are the International Avogadro Coordination and the watt balance projects. Both of these approaches involve realizing a kilogram in vacuum and therefore the traceability from a kilogram realized in vacuum to mass standards in air is crucial to the effective dissemination of the mass scale. The work reported here characterizes the changes in mass values of standards on transfer between air and vacuum and thus will enable traceability to be established for an in-air mass scale based on a definition of the unit in vacuum.

  17. Effect of the relative optical air mass and the clearness index on solar erythemal UV irradiance.

    PubMed

    Moreno, J C; Serrano, M A; Cañada, J; Gurrea, G; Utrillas, M P

    2014-09-05

    This paper analyses the effects of the clearness index (Kt) and the relative optical air mass (mr) on erythemal UV irradiance (UVER). The UVER measurements were made in Valencia (Spain) from 6:00 am to 6:00 pm between June 2003 and December 2012 and (140,000 data points). Firstly, two models were used to calculate values for the erythemal ultraviolet irradiance clearness index (KtUVER) as a function of the global irradiance clearness index (Kt). Secondly, a potential regression model to measure the KtUVER as a function of the relative optical air mass was studied. The coefficients of this regression were evaluated for clear and cloudy days, as well as for days with high and low ozone levels. Thirdly, an analysis was made of the relationship between the two effects in the experimental database, with it being found that the highest degree of agreement, or the joint highest frequencies, are located in the optical mass range mr∈[1.0, 1.2] and the clearness index range of Kt∈[0.8, 1.0]. This is useful for establishing the ranges of parameters where models are more efficient. Simple equations have been tested that can provide additional information for the engineering projects concerning thermal installations. Fourthly, a high dispersion of radiation data was observed for intermediate values of the clearness for UV and UVER.

  18. The effect of long-range air mass transport pathways on PM10 and NO2 concentrations at urban and rural background sites in Ireland: Quantification using clustering techniques.

    PubMed

    Donnelly, Aoife A; Broderick, Brian M; Misstear, Bruce D

    2015-01-01

    The specific aims of this paper are to: (i) quantify the effects of various long range transport pathways nitrogen dioxide (NO2) and particulate matter with diameter less than 10μm (PM10) concentrations in Ireland and identify air mass movement corridors which may lead to incidences poor air quality for application in forecasting; (ii) compare the effects of such pathways at various sites; (iii) assess pathways associated with a period of decreased air quality in Ireland. The origin of and the regions traversed by an air mass 96h prior to reaching a receptor is modelled and k-means clustering is applied to create air-mass groups. Significant differences in air pollution levels were found between air mass cluster types at urban and rural sites. It was found that easterly or recirculated air masses lead to higher NO2 and PM10 levels with average NO2 levels varying between 124% and 239% of the seasonal mean and average PM10 levels varying between 103% and 199% of the seasonal mean at urban and rural sites. Easterly air masses are more frequent during winter months leading to higher overall concentrations. The span in relative concentrations between air mass clusters is highest at the rural site indicating that regional factors are controlling concentration levels. The methods used in this paper could be applied to assist in modelling and forecasting air quality based on long range transport pathways and forecast meteorology without the requirement for detailed emissions data over a large regional domain or the use of computationally demanding modelling techniques.

  19. Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

    NASA Technical Reports Server (NTRS)

    Shirley, John A.; Winter, Michael

    1993-01-01

    An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

  20. Seasonal, anthropogenic, air mass, and meteorological influences on the atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs): Evidence for the importance of diffuse combustion sources

    SciTech Connect

    Lee, R.G.M.; Green, N.J.L.; Lohmann, R.; Jones, K.C.

    1999-09-01

    Sampling programs were undertaken to establish air polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations at a semirural site on the northwest coast of England in autumn and summer and to investigate factors causing their variability. Changing source inputs, meteorological parameters, air masses, and the impact of a festival when it is customary to light fireworks and bonfires were investigated. Various lines of evidence from the study point to diffuse, combustion-related sources being a major influence on ambient air concentrations. Higher PCDD/F concentrations were generally associated with air masses that had originated and moved over land, particularly during periods of low ambient temperature. Low concentrations were associated with air masses that had arrived from the Atlantic Ocean/Irish Sea to the west of the sampling site and had little or no contact with urban/industrialized areas. Concentrations in the autumn months were 2 to 10 times higher than those found in the summer.

  1. Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry.

    PubMed

    Benmakhlouf, Hamza; Bouchard, Hugo; Fransson, Annette; Andreo, Pedro

    2011-11-21

    Backscatter factors, B, and mass energy-absorption coefficient ratios, (μ(en)/ρ)(w, air), for the determination of the surface dose in diagnostic radiology were calculated using Monte Carlo simulations. The main purpose was to extend the range of available data to qualities used in modern x-ray techniques, particularly for interventional radiology. A comprehensive database for mono-energetic photons between 4 and 150 keV and different field sizes was created for a 15 cm thick water phantom. Backscattered spectra were calculated with the PENELOPE Monte Carlo system, scoring track-length fluence differential in energy with negligible statistical uncertainty; using the Monte Carlo computed spectra, B factors and (μ(en)/ρ)(w, air) were then calculated numerically for each energy. Weighted averaging procedures were subsequently used to convolve incident clinical spectra with mono-energetic data. The method was benchmarked against full Monte Carlo calculations of incident clinical spectra obtaining differences within 0.3-0.6%. The technique used enables the calculation of B and (μ(en)/ρ)(w, air) for any incident spectrum without further time-consuming Monte Carlo simulations. The adequacy of the extended dosimetry data to a broader range of clinical qualities than those currently available, while keeping consistency with existing data, was confirmed through detailed comparisons. Mono-energetic and spectra-averaged values were compared with published data, including those in ICRU Report 74 and IAEA TRS-457, finding average differences of 0.6%. Results are provided in comprehensive tables appropriated for clinical use. Additional qualities can easily be calculated using a designed GUI interface in conjunction with software to generate incident photon spectra.

  2. Ozone Modulation/Membrane Introduction Mass Spectrometry for Analysis of Hydrocarbon Pollutants in Air

    NASA Astrophysics Data System (ADS)

    Atkinson, D. B.

    2001-12-01

    Modulation of volatile hydrocarbons in two-component mixtures is demonstrated using an ozonolysis pretreatment with membrane introduction mass spectrometry (MIMS). The MIMS technique allows selective introduction of volatile and semivolatile analytes into a mass spectrometer via processes known collectively as pervaporation [Kotiaho and Cooks, 1992]. A semipermeable polymer membrane acts as an interface between the sample (vapor or solution) and the vacuum of the mass spectrometer. This technique has been demonstrated to allow for sensitive analysis of hydrocarbons and other non-polar volatile organic compounds (VOC`s) in air samples[Cisper et al., 1995] . The methodology has the advantages of no sample pretreatment and short analysis time, which are promising for online monitoring applications but the chief disadvantage of lack of a separation step for the different analytes in a mixture. Several approaches have been investigated to overcome this problem including use of selective chemical ionization [Bier and Cooks, 1987] and multivariate calibration techniques[Ketola et al., 1999] . A new approach is reported for the quantitative measurement of VOCs in complex matrices. The method seeks to reduce the complexity of mass spectra observed in hydrocarbon mixture analysis by selective pretreatment of the analyte mixture. In the current investigation, the rapid reaction of ozone with alkenes is used, producing oxygenated compounds which are suppressed by the MIMS system. This has the effect of removing signals due to unsaturated analytes from the compound mass spectra, and comparison of the spectra before and after the ozone treatment reveals the nature of the parent compounds. In preliminary investigations, ozone reacted completely with cyclohexene from a mixture of cylohexene and cyclohexane, and with β -pinene from a mixture of toluene and β -pinene, suppressing the ion signals from the olefins. A slight attenuation of the cyclohexane and toluene in those

  3. Evidence for widespread tropospheric Cl chemistry in free tropospheric air masses from the South China Sea

    NASA Astrophysics Data System (ADS)

    Baker, Angela K.; Sauvage, Carina; Thorenz, Ute R.; Brenninkmeijer, Carl A. M.; Oram, David E.; van Velthoven, Peter; Zahn, Andreas; Williams, Jonathan

    2015-04-01

    While the primary global atmospheric oxidant is the hydroxyl radical (OH), under certain circumstances chlorine radicals (Cl) can compete with OH and perturb the oxidative cycles of the troposphere. During flights between Bangkok, Thailand and Kuala Lumpur, Malaysia conducted over two fall/winter seasons (November 2012 - March 2013 and November 2013 - January 2014) the IAGOS-CARIBIC (www.caribic-atmospheric.com) observatory consistently encountered free tropospheric air masses (9-11 km) originating over the South China Sea which had non-methane hydrocarbon (NMHC) signatures characteristic of processing by Cl. These signatures were observed in November and December of both years, but were not seen in other months, suggesting that oxidation by Cl is a persistent seasonal feature in this region. These Cl signatures were observed over a range of ~1500 km indicating a large-scale phenomenon. In this region, where transport patterns facilitate global redistribution of pollutants and persistent deep convection creates a fast-track for cross-tropopause transport, there exists the potential for regional chemistry to have impacts further afield. Here we use observed relationships between NMHCs to estimate the significance and magnitude of Cl oxidation in this region. From the relative depletions of NMHCs in these air masses we infer OH to Cl ratios of 83±28 to 139±40 [OH]/[Cl], which we believe represents an upper limit, based on the technique employed. At a predicted average [OH] of 1.5×106 OH cm-3 this corresponds to an average (minimum) [Cl] exposure of 1-2×104 Cl cm-3 during air mass transport. Lastly, in addition to estimating Cl abundances we have used IAGOS-CARIBIC observations to elucidate whether the origin of this Cl is predominantly natural or anthropogenic.

  4. Characterization of key aerosol, trace gas and meteorological properties and particle formation and growth processes dependent on air mass origins in coastal Southern Spain

    NASA Astrophysics Data System (ADS)

    Diesch, J.; Drewnick, F.; Sinha, V.; Williams, J.; Borrmann, S.

    2011-12-01

    acid was found to be the main particle formation contributor. The AMS analysis showed inorganic sulfate species being substantially higher during the growth stages of urban compared to continentally influenced events that are characterized by lower PM1 mass concentrations mainly composed of oxidized organics. The lowest average PM1 mass and number concentrations (2 μg m-3, 1000 cm-3) were found in marine air mass types characterized by the highest sulfate PM1-fraction (54%, 0.91 μg m-3) and volume size distributions probably dominated by sodium chloride particles from sea spray. Two to five times higher submicron aerosol mass concentrations were observed in continental (2.5 μg m-3) and urban (4.2 μg m-3) air mass types mainly consisting of organic species that were further evaluated using Positive Matrix Factorization (PMF). Zhang, Q. et al. (2004), Environ. Sci. Technol., 38, 4797-4809.

  5. Air mass characterization during the DAURE field campaign by PTR-TOF

    NASA Astrophysics Data System (ADS)

    Metzger, Axel; Schallhart, Simon; Müller, Markus; Hansel, Armin

    2010-05-01

    Volatile organic compounds (VOCs) are emitted into the atmosphere from a wide variety of biogenic and anthropogenic sources. Although some of the sources are well characterized, many uncertainties remain about the fate of these compounds in the atmosphere and their role in organic aerosol formation. Here we present measurements using Proton Transfer Reaction Time-of-Flight (PTR-TOF) Mass Spectrometry during the DAURE field campaign ("Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean") obtained during February and March 2009. Measurements were performed at a rural mountain site located in the Montseny Natural Park 40 km to the NNE of the city of Barcelona, and 25 km from the Mediterranean coast. Volatile organic compounds where identified and quantified using PTR-TOF with 1 minute time resolution. The instruments mass resolving power of 4000 - 5000 and a mass accuracy of 5 ppm allows for the unambiguous sum-formula identification of e.g. hydrocarbons (HCs) or oxygenated VOCs (OVOCs). The high time resolution allows separating out on site pollution events. Air masses impacted by biomass-burning, urban, marine and vegetation emissions are characterized using tracers like acetonitrile, aromatics, dimethyl sulfide or biogenic compounds (terpenoids) and the degree of photochemical processing is inferred from the data.

  6. Air mass distribution and the heterogeneity of the climate change signal in the Hudson Bay/Foxe Basin region, Canada

    NASA Astrophysics Data System (ADS)

    Leung, Andrew; Gough, William

    2016-08-01

    The linkage between changes in air mass distribution and temperature trends from 1971 to 2010 is explored in the Hudson Bay/Foxe Basin region. Statistically significant temperature increases were found of varying spatial and temporal magnitude. Concurrent statistically significant changes in air mass frequency at the same locations were also detected, particularly in the declining frequency of dry polar (DP) air. These two sets of changes were found to be linked, and we thus conclude that the heterogeneity of the climatic warming signal in the region is at least partially the result of a fundamental shift in the concurrent air mass frequency in addition to global and regional changes in radiative forcing due to increases in long-lived greenhouse gases.

  7. Mixture model-based atmospheric air mass classification: a probabilistic view of thermodynamic profiles

    NASA Astrophysics Data System (ADS)

    Pernin, Jérôme; Vrac, Mathieu; Crevoisier, Cyril; Chédin, Alain

    2016-10-01

    Air mass classification has become an important area in synoptic climatology, simplifying the complexity of the atmosphere by dividing the atmosphere into discrete similar thermodynamic patterns. However, the constant growth of atmospheric databases in both size and complexity implies the need to develop new adaptive classifications. Here, we propose a robust unsupervised and supervised classification methodology of a large thermodynamic dataset, on a global scale and over several years, into discrete air mass groups homogeneous in both temperature and humidity that also provides underlying probability laws. Temperature and humidity at different pressure levels are aggregated into a set of cumulative distribution function (CDF) values instead of classical ones. The method is based on a Gaussian mixture model and uses the expectation-maximization (EM) algorithm to estimate the parameters of the mixture. Spatially gridded thermodynamic profiles come from ECMWF reanalyses spanning the period 2000-2009. Different aspects are investigated, such as the sensitivity of the classification process to both temporal and spatial samplings of the training dataset. Comparisons of the classifications made either by the EM algorithm or by the widely used k-means algorithm show that the former can be viewed as a generalization of the latter. Moreover, the EM algorithm delivers, for each observation, the probabilities of belonging to each class, as well as the associated uncertainty. Finally, a decision tree is proposed as a tool for interpreting the different classes, highlighting the relative importance of temperature and humidity in the classification process.

  8. Impact of maritime air mass trajectories on the Western European coast urban aerosol.

    PubMed

    Almeida, S M; Silva, A I; Freitas, M C; Dzung, H M; Caseiro, A; Pio, C A

    2013-01-01

    Lisbon is the largest urban area in the Western European coast. Due to this geographical position the Atlantic Ocean serves as an important source of particles and plays an important role in many atmospheric processes. The main objectives of this study were to (1) perform a chemical characterization of particulate matter (PM2.5) sampled in Lisbon, (2) identify the main sources of particles, (3) determine PM contribution to this urban area, and (4) assess the impact of maritime air mass trajectories on concentration and composition of respirable PM sampled in Lisbon. During 2007, PM2.5 was collected on a daily basis in the center of Lisbon with a Partisol sampler. The exposed Teflon filters were measured by gravimetry and cut into two parts: one for analysis by instrumental neutron activation analysis (INAA) and the other by ion chromatography (IC). Principal component analysis (PCA) and multilinear regression analysis (MLRA) were used to identify possible sources of PM2.5 and determine mass contribution. Five main groups of sources were identified: secondary aerosols, traffic, calcium, soil, and sea. Four-day backtracking trajectories ending in Lisbon at the starting sampling time were calculated using the HYSPLIT model. Results showed that maritime transport scenarios were frequent. These episodes were characterized by a significant decrease of anthropogenic aerosol concentrations and exerted a significant role on air quality in this urban area.

  9. Precipitation chemistry and corresponding transport patterns of influencing air masses at Huangshan Mountain in East China

    NASA Astrophysics Data System (ADS)

    Shi, ChunE; Deng, Xueliang; Yang, Yuanjian; Huang, Xiangrong; Wu, Biwen

    2014-09-01

    One hundred and ten samples of rainwater were collected for chemical analysis at the summit of Huangshan Mountain, a high-altitude site in East China, from July 2010 to June 2011. The volume-weighted-mean (VWM) pH for the whole sampling period was 5.03. SO{4/2-} and Ca2+ were the most abundant anion and cation, respectively. The ionic concentrations varied monthly with the highest concentrations in winter/spring and the lowest in summer. Evident inter-correlations were found among most ions, indicating the common sources for some species and fully mixing characteristics of the alpine precipitation chemistry. The VWM ratio of [SO{4/2-}]/[NO{3/-}] was 2.54, suggesting the acidity of rainwater comes from both nitric and sulfuric acids. Compared with contemporary observations at other alpine continental sites in China, the precipitation at Huangshan Mountain was the least polluted, with the lowest ionic concentrations. Trajectories to Huangshan Mountain on rainy days could be classified into six groups. The rainwater with influencing air masses originating in Mongolia was the most polluted with limited effect. The emissions of Jiangxi, Anhui, Zhejiang and Jiangsu provinces had a strong influence on the overall rain chemistry at Huangshan Mountain. The rainwater with influencing air masses from Inner Mongolia was heavily polluted by anthropogenic pollutants.

  10. The impact of air mass advection on aerosol optical properties over Gotland (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Zdun, Agnieszka; Rozwadowska, Anna; Kratzer, Susanne

    2016-12-01

    In the present paper, measurements of aerosol optical properties from the Gotland station of the AERONET network, combined with a two-stage cluster analysis of back trajectories of air masses moving over Gotland, were used to identify the main paths of air mass advection to the Baltic Sea and to relate them to aerosol optical properties, i.e. the aerosol optical thickness at the wavelength λ = 500 nm, AOT (500) and the Ångström exponent for the spectral range from 440 to 870 nm, α(440,870). One- to six-day long back trajectories ending at 300, 500 and 3000 m above the station were computed using the HYSPLIT model. The study shows that in the Gotland region, variability in aerosol optical thickness AOT(500) is more strongly related to advections in the boundary layer than to those in the free troposphere. The observed variability in AOT(500) was best explained by the advection speeds and directions given by clustering of 4-day backward trajectories of air arriving in the boundary layer at 500 m above the station. 17 clusters of 4-day trajectories arriving at altitude 500 m above the Gotland station (sea level) derived using two-stage cluster analysis differ from each other with respect to trajectory length, the speed of air mass movement and the direction of advection. They also show different cluster means of AOT(500) and α(440,870). The cluster mean AOT(500) ranges from 0.342 ± 0.012 for the continental clusters M2 (east-southeast advection with moderate speed) and 0.294 ± 0.025 for S5 (slow south-southeast advection) to 0.064 ± 0.002 and 0.069 ± 0.002 for the respective marine clusters L3 (fast west-northwest advection) and M3 (north-northwest advection with moderate speed). The cluster mean α(440,870) varies from 1.65-1.70 for the short-trajectory clusters to 0.98 ± 0.03 and 1.06 ± 0.03 for the Arctic marine cluster L4 (fast inflow from the north) and marine cluster L5 (fast inflow from the west) respectively.

  11. Factors Affecting Scholarly Research among Mass Communications Faculty.

    ERIC Educational Resources Information Center

    Schweitzer, John C.

    1989-01-01

    Identifies factors that contribute most to productive scholars' success as published researchers. Finds that personal motivation is the strongest factor contributing to an individual researcher's productivity. (RS)

  12. Research report on the physiological effects of air ions and their significance as environmental factors

    NASA Technical Reports Server (NTRS)

    Varga, A.

    1978-01-01

    The series of experiments performed have shown that small air ions generated artificially using radioactive materials produced physiological effects in all test subjects, which are described. These results show that the air ions were important climatic factors in the production of comfortable and healthy room climates.

  13. Use of stable lead isotopes and trace metals to characterize air mass sources into the eastern North Atlantic

    NASA Astrophysics Data System (ADS)

    VéRon, Alain J.; Church, Thomas M.

    1997-12-01

    Stable lead isotopes (204Pb, 206Pb, 207Pb, 208Pb) and trace metals (Mn, Al, Fe, Ni, Cu, Cd, Zn, Pb) have been analyzed in aerosol collected during the Atlantic Stratocumulus Transition Experiment-Marine Aerosol and Gas Exchange (ASTEX-MAGE) cruise that transited between Miami and the Azores from May to July 1992. Our goal was to define the continental signatures of the air masses encountered between the Azores and the subtropical regions. The combination of air mass trajectories, trace metal concentrations and stable lead isotopes allowed us to characterize the anthropogenic character of encountered air masses. The average 206Pb/207Pb ratio was 1.148±0.021 and corresponded to a mixing between well defined European (such as Great Britain with 1.115<206Pb/207Pb<1.125 and France with 206Pb/207Pb=1.141±0.000) and North American sources (with 206Pb/207Pb=1.184±0.000). On the basis of air mass trajectories and trace metal concentrations, the background isotopic signature associated with the trade winds (206Pb/207Pb=1.161±0.004) is consistent with previous reports by Church et al. [1990] such as 206Pb/207Pb=1.154±0.004 in 1988, (Véron et al., 1993), 206Pb/207Pb=1.155±0.004 in 1989, and Hamelin et al. [1996] (206Pb/207Pb=1.158±0.006) in 1991. Short-term variations of continental air mass sources was particularly investigated by considering the anthropogenic character of aerosols collected during two Lagrangian experiments conducted as part of the ASTEX-MAGE cruise. We demonstrated the utility of stable lead isotopes to assign a "continental source signature" (or mixture thereof) to air masses beyond that normally possible by conventional air mass trajectory analysis in remote oceanic regions.

  14. Trends and sources vs air mass origins in a major city in South-western Europe: Implications for air quality management.

    PubMed

    Fernández-Camacho, R; de la Rosa, J D; Sánchez de la Campa, A M

    2016-05-15

    This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air mass origins. Hourly, daily and seasonal variation of PM10 and gaseous pollutant concentrations (CO, NO2 and SO2), all of them showing negative trends during the study period, point to the traffic as one of the main sources of air pollution in Seville. Mineral dust, secondary inorganic compounds (SIC) and trace elements showed higher concentrations under North African (NAF) air mass origins than under Atlantic. We observe a decreasing trend in all chemical components of PM10 under both types of air masses, NAF and Atlantic. Principal component analysis using more frequent air masses in the area allows the identification of five PM10 sources: crustal, regional, marine, traffic and industrial. Natural sources play a more relevant role during NAF events (20.6 μg · m(-3)) than in Atlantic episodes (13.8 μg · m(-3)). The contribution of the anthropogenic sources under NAF doubles the one under Atlantic conditions (33.6 μg · m(-3) and 15.8 μg · m(-3), respectively). During Saharan dust outbreaks the frequent accumulation of local anthropogenic pollutants in the lower atmosphere results in poor air quality and an increased risk of mortality. The results are relevant when analysing the impact of anthropogenic emissions on the exposed population in large cities. The increase in potentially toxic elements during Saharan dust outbreaks should also be taken into account when discounting the number of exceedances attributable to non-anthropogenic or natural origins.

  15. PTRAC File Utilization for Calculation of Free-Air Ionization Chamber Correction Factors by MCNPX

    NASA Astrophysics Data System (ADS)

    Šolc, Jaroslav; Sochor, Vladimír

    2014-06-01

    A free-air ionization chamber is used as a standard of photon air-kerma. Several correction factors are applied to the air-kerma value. Correction factors for electron loss (kloss) and for additional ionization current caused by photon scatter (ksc), photon fluorescence (kfl), photon transmission through diaphragm edge (kdtr), and photon scatter from the surface of the diaphragm aperture (kdsc) were determined by the MCNPX code utilizing information stored in Particle Track (PTRAC) output files. Individual steps of the procedure are described and the calculated values of the correction factors are presented. The values are in agreement with the correction factors published in a literature for similar free-air chambers.

  16. The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-Convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Zavodsky, B. T.; Moltham, A. L.; Folmer, M. J.; Jedlovec, G. J.

    2014-01-01

    The investigation of non-convective winds associated with passing extratropical cyclones and the formation of the sting jet in North Atlantic cyclones that impact Europe has been gaining interest. Sting jet research has been limited to North Atlantic cyclones that impact Europe because it is known to occur in Shapiro-Keyser cyclones and theory suggests it does not occur in Norwegian type cyclones. The global distribution of sting jet cyclones is unknown and questions remain as to whether cyclones with Shapiro-Keyser characteristics that impact the United States develop features similar to the sting jet. Therefore unique National Aeronautics and Space Administration (NASA) products were used to analyze an event that impacted the Northeast United States on 09 February 2013. Moderate Resolution Imaging Spectroradiometer (MODIS) Red Green Blue (RGB) Air Mass imagery and Atmospheric Infrared Sounder (AIRS) ozone data were used in conjunction with NASA's global Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis and higher-resolution regional 13-km Rapid Refresh (RAP) data to analyze the role of stratospheric air in producing high winds. The RGB Air Mass imagery and a new AIRS ozone anomaly product were used to confirm the presence of stratospheric air. Plan view and cross sectional plots of wind, potential vorticity, relative humidity, omega, and frontogenesis were used to analyze the relationship between stratospheric air and high surface winds during the event. Additionally, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to plot trajectories to determine the role of the conveyor belts in producing the high winds. Analyses of new satellite products, such as the RGB Air Mass imagery, show the utility of future GOES-R products in forecasting non-convective wind events.

  17. An effective indicator of continental scale cold air outbreaks in northern winter: the intensity variation of the meridional mass circulation

    NASA Astrophysics Data System (ADS)

    Ren, R.; Yu, Y.; Cai, M.

    2015-12-01

    This study reports that the intensity variation of the meridional mass circulation can be an effective leading indicator of cold air outbreaks (CAOs) over midlatitudes in northern winter. It is found that continental-scale coldness by cold air outbreaks (CAOs) tend to preferentially occur within a week after stronger mass circulation events defined as the peak time when the net mass transport across 60°N in the upper warm or the lower cold air branch exceeds ~88×109 kg s-1. During weaker mass circulation events when the net mass transport across 60°N is below ~71.6×109 kg s-1, most areas of the mid-latitudes are generally in mild condition except the northern part of Western Europe. Composite pattern of circulation anomalies during stronger mass circulation events greatly resemble that of the winter-mean, with the two main routes of anomalous cold air outbreaks being along the climatological routes of polar cold air, namely, via East Asia and North America. The Siberian High shifts westward during stronger mass circulation events, opening up a third route of cold air outbreaks through Eastern Europe. The relationship of CAOs with Arctic Oscillation (AO) is less robust because temporal changes of AO are resulted from a small imbalance between the poleward and equatorward branches of the mass circulation. Only when the poleward branch leads the equatorward branch (44% of all cases), CAOs tend to take place within a week after a negative phase of AO. The daily ERA-Interim reanalysis data set for the 32 winters in 1979-2011 were used in this study.

  18. Exogenous factors contributing to column bed heterogeneity: Part 1: Consequences of 'air' injections in liquid chromatography.

    PubMed

    Samuelsson, Jörgen; Fornstedt, Torgny; Shalliker, Andrew

    2015-08-07

    It has been shown that not only the packing homogeneity, but also factors external to the column bed, such as, frits and distributors can have important effects on the column performance. This current communication is the first in a series focusing on the impact of exogenous factors on the column bed heterogeneity. This study is based on several observations by us and others that chromatographic runs often, for technical reasons, include more or less portions of air in the injections. It is therefore extremely important to find out the impact of air on the column performance, the reliability of the results derived from analyses where air was injected, and the effect on the column homogeneity. We used a photographic approach for visualising the air transport phenomena, and found that the air transport through the column is comprised of many different types of transport phenomena, such as laminal flow, viscous fingering like flows, channels and bulbs, and pulsations. More particularly, the air clouds within the column definitely interact in the adsorption, i.e. mobile phase adsorbed to the column surface is displaced. In addition, irrespective of the type of air transport phenomena, the air does not penetrate the column homogeneously. This process is strongly flow dependent. In this work we study air transport both in an analytical scale and a semi-prep column.

  19. The collision cross sections of iodide salt cluster ions in air via differential mobility analysis-mass spectrometry.

    PubMed

    Ouyang, Hui; Larriba-Andaluz, Carlos; Oberreit, Derek R; Hogan, Christopher J

    2013-12-01

    To date, most collision cross section (CCS) predictions have invoked gas molecule impingement-reemission rules in which specular and elastic scattering of spherical gas molecules from rigid polyatomic surfaces are assumed. Although such predictions have been shown to agree well with CCSs measured in helium bath gas, a number of studies reveal that these predictions do not agree with CCSs for ions in diatomic gases, namely, air and molecular nitrogen. To further examine the validity of specular-elastic versus diffuse-inelastic scattering models, we measured the CCSs of positively charged metal iodide cluster ions of the form [MI]n[M(+)]z, where M = Na, K, Rb, or Cs, n = 1 - 25, and z = 1 - 2. Measurements were made in air via differential mobility analysis mass spectrometry (DMA-MS). The CCSs measured are compared with specular-elastic as well as diffuse-inelastic scattering model predictions with candidate ion structures determined from density functional theory. It is found that predictions from diffuse-inelastic collision models agree well (within 5%) with measurements from sodium iodide cluster ions, while specular-elastic collision model predictions are in better agreement with cesium iodide cluster ion measurements. The agreement with diffuse-inelastic and specular-elastic predictions decreases and increases, respectively, with increasing cation mass. However, even when diffuse-inelastic cluster ion predictions disagree with measurements, the disagreement is of a near-constant factor for all ions, indicating that a simple linear rescaling collapses predictions to measurements. Conversely, rescaling cannot be used to collapse specular-elastic predictions to measurements; hence, although the precise impingement reemission rules remain ambiguous, they are not specular-elastic.

  20. The Collision Cross Sections of Iodide Salt Cluster Ions in Air via Differential Mobility Analysis-Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ouyang, Hui; Larriba-Andaluz, Carlos; Oberreit, Derek R.; Hogan, Christopher J.

    2013-12-01

    To date, most collision cross section (CCS) predictions have invoked gas molecule impingement-reemission rules in which specular and elastic scattering of spherical gas molecules from rigid polyatomic surfaces are assumed. Although such predictions have been shown to agree well with CCSs measured in helium bath gas, a number of studies reveal that these predictions do not agree with CCSs for ions in diatomic gases, namely, air and molecular nitrogen. To further examine the validity of specular-elastic versus diffuse-inelastic scattering models, we measured the CCSs of positively charged metal iodide cluster ions of the form [MI]n[M+]z, where M = Na, K, Rb, or Cs, n = 1 - 25, and z = 1 - 2. Measurements were made in air via differential mobility analysis mass spectrometry (DMA-MS). The CCSs measured are compared with specular-elastic as well as diffuse-inelastic scattering model predictions with candidate ion structures determined from density functional theory. It is found that predictions from diffuse-inelastic collision models agree well (within 5 %) with measurements from sodium iodide cluster ions, while specular-elastic collision model predictions are in better agreement with cesium iodide cluster ion measurements. The agreement with diffuse-inelastic and specular-elastic predictions decreases and increases, respectively, with increasing cation mass. However, even when diffuse-inelastic cluster ion predictions disagree with measurements, the disagreement is of a near-constant factor for all ions, indicating that a simple linear rescaling collapses predictions to measurements. Conversely, rescaling cannot be used to collapse specular-elastic predictions to measurements; hence, although the precise impingement reemission rules remain ambiguous, they are not specular-elastic.

  1. Examination of the mass media process and personal factors affecting the assessment of mass media-disseminated health information.

    PubMed

    Avcı, Kadriye; Çakır, Tülin; Avşar, Zakir; Üzel Taş, Hanife

    2015-06-01

    This study examined the mass media and personal characteristics leading to health communication inequality as well as the role of certain factors in health communication's mass media process. Using both sociodemographic variables and Maletzke's model as a basis, we investigated the relationship between selected components of the mass communication process, the receiving of reliable health information as a result of health communication, and the condition of its use. The study involved 1853 people in Turkey and was structured in two parts. The first part dealt with questions regarding sociodemographic characteristics, the use of the mass media and the public's ability to obtain health information from it, the public's perception of the trustworthiness of health information, and the state of translating this information into health-promoting behaviours. In the second part, questions related to the mass communication process were posed using a five-point Likert scale. This section tried to establish structural equation modelling using the judgements prepared on the basis of the mass media model. Through this study, it has been observed that sociodemographic factors such as education and age affect individuals' use of and access to communication channels; individuals' trust in and selection of health information from the programme content and their changing health behaviours (as a result of the health information) are related to both their perception of the mass communication process and to sociodemographic factors, but are more strongly related to the former.

  2. Air mass modification over Europe: EARLINET aerosol observations from Wales to Belarus

    NASA Astrophysics Data System (ADS)

    Wandinger, Ulla; Mattis, Ina; Tesche, Matthias; Ansmann, Albert; BöSenberg, Jens; Chaikovski, Anatoly; Freudenthaler, Volker; Komguem, Leonce; Linné, Holger; Matthias, Volker; Pelon, Jacques; Sauvage, Laurent; Sobolewski, Piotr; Vaughan, Geraint; Wiegner, Matthias

    2004-12-01

    For the first time, the vertically resolved aerosol optical properties of western and central/eastern European haze are investigated as a function of air mass transport. Special emphasis is put on clean maritime air masses that cross the European continent from the west and become increasingly polluted on their way into the continent. The study is based on observations at seven lidar stations (Aberystwyth, Paris, Hamburg, Munich, Leipzig, Belsk, and Minsk) of the European Aerosol Research Lidar Network (EARLINET) and on backward trajectory analysis. For the first time, a lidar network monitored continent-scale haze air masses for several years (since 2000). Height profiles of the particle backscatter coefficient and the particle optical depth of the planetary boundary layer (PBL) at 355-nm wavelength are analyzed for the period from May 2000 to November 2002. From the observations at Aberystwyth, Wales, the aerosol reference profile for air entering Europe from pristine environments was determined. A mean 355-nm optical depth of 0.05 and a mean PBL height of 1.5 km was found for clean maritime summer conditions. The particle optical depth and PBL height increased with increasing distance from the North Atlantic. Mean summer PBL heights were 1.9-2.8 km at the continental sites of Leipzig, Belsk, and Minsk. Winter mean PBL heights were mostly between 0.7 and 1.3 km over the seven EARLINET sites. Summer mean 355-nm optical depths increased from 0.17 (Hamburg, northwesterly airflow from the North Sea) and 0.21 (Paris, westerly flow from the Atlantic) over 0.33 (Hamburg, westerly flow) and 0.35 (Leipzig, westerly flow) to 0.59 (Belsk, westerly flow), and decreased again to 0.37 (westerly flow) at Minsk. Winter mean optical depths were, on average, 10-30% lower than the respective summer values. PBL-mean extinction coefficients were of the order of 200 Mm-1 at 355 nm at Hamburg and Leipzig, Germany, and close to 600 Mm-1 at Belsk, Poland, in winter for westerly flows

  3. An Air Mass Based Approach to the Establishment of Spring Season Synoptic Characteristics in the Northeast United States

    NASA Astrophysics Data System (ADS)

    Zander, R.; Messina, A.; Godek, M. L.

    2012-12-01

    The spring season is indicative of marked meteorological, ecological, and biological changes across the Northeast United States. The onset of spring coincides with distinct meteorological phenomena including an increase in severe weather events and snow meltwaters that can cause localized flooding and other costly damages. Increasing and variable springtime temperatures also influence Northeast tourist operations and agricultural productivity. Even with the vested interest of industry in the season and public awareness of the dynamic characteristics of spring, the definition of spring remains somewhat arbitrary. The primary goal of this research is to obtain a synoptic meteorological definition of the spring season through an assessment of air mass frequency over the past 60 years. A secondary goal examines the validity of recent speculations that the onset and termination of spring has changed in recent decades, particularly since 1975. The Spatial Synoptic Classification is utilized to define daily air masses over the region. Annual and seasonal baseline frequencies are identified and their differences are acquired to characterize the season. Seasonal frequency departures of the early and late segments of the period of record around 1975 are calculated and examined for practical and statistical significance. The daily boundaries of early and late spring are then isolated and frequencies are obtained for these periods. Boundary frequencies are assessed across the period of record to identify important changes in the season's initiation and termination through time. Results indicate that the Northeast spring season is dominated by dry air masses, mainly the Dry Moderate and Dry Polar types. Significant differences in seasonal air mass frequency are also observed through time. Prior to 1975, higher frequencies of polar air mass types are detected while after 1975 there is an increase in the frequencies of both moderate and tropical types. This finding is also

  4. Susceptibility Factors Relevant for the Association Between Long-Term Air Pollution Exposure and Incident Asthma.

    PubMed

    Burte, Emilie; Nadif, Rachel; Jacquemin, Bénédicte

    2016-03-01

    In this review, we identified 15 studies in children and 10 studies in adults that assessed the association between long-term exposure to air pollution and incident asthma and that conducted stratified analyses to explore potential susceptibility factors. Overall, adult never-/former smokers seem to be at higher risk of incident asthma due to air pollution. Children without atopy and children from low socioeconomic status families also seem to be at higher risk of incident asthma due to air pollution. While interaction between air pollution and genes involved in the response to oxidative stress pathways have been explored, results are somewhat inconsistent and in need of replication. To evaluate interactions, large sample sizes are necessary, and much more research, including data pooling from existing studies, is needed to further explore susceptibility factors for asthma incidence due to long-term air pollution exposure.

  5. [Estimation of average traffic emission factor based on synchronized incremental traffic flow and air pollutant concentration].

    PubMed

    Li, Run-Kui; Zhao, Tong; Li, Zhi-Peng; Ding, Wen-Jun; Cui, Xiao-Yong; Xu, Qun; Song, Xian-Feng

    2014-04-01

    On-road vehicle emissions have become the main source of urban air pollution and attracted broad attentions. Vehicle emission factor is a basic parameter to reflect the status of vehicle emissions, but the measured emission factor is difficult to obtain, and the simulated emission factor is not localized in China. Based on the synchronized increments of traffic flow and concentration of air pollutants in the morning rush hour period, while meteorological condition and background air pollution concentration retain relatively stable, the relationship between the increase of traffic and the increase of air pollution concentration close to a road is established. Infinite line source Gaussian dispersion model was transformed for the inversion of average vehicle emission factors. A case study was conducted on a main road in Beijing. Traffic flow, meteorological data and carbon monoxide (CO) concentration were collected to estimate average vehicle emission factors of CO. The results were compared with simulated emission factors of COPERT4 model. Results showed that the average emission factors estimated by the proposed approach and COPERT4 in August were 2.0 g x km(-1) and 1.2 g x km(-1), respectively, and in December were 5.5 g x km(-1) and 5.2 g x km(-1), respectively. The emission factors from the proposed approach and COPERT4 showed close values and similar seasonal trends. The proposed method for average emission factor estimation eliminates the disturbance of background concentrations and potentially provides real-time access to vehicle fleet emission factors.

  6. Datalink in air traffic management: Human factors issues in communications.

    PubMed

    Stedmon, Alex W; Sharples, Sarah; Littlewood, Robert; Cox, Gemma; Patel, Harshada; Wilson, John R

    2007-07-01

    This paper examines issues underpinning the potential move in aviation away from real speech radiotelephony (R/T) communications towards datalink communications involving text and synthetic speech communications. Using a novel air traffic control (ATC) task, two experiments are reported. Experiment 1 compared the use of speech and text while Experiment 2 compared the use of real and synthetic speech communications. Results indicated that generally there were no significant differences between speech and text communications and that either type could be used without any main effects on performance. However, a number of specific differences were observed across the different phases of the scenarios indicating that workload levels may be more varied when speech communications are used. Experiment 2 illustrated that participants placed a greater level of trust in real speech than synthetic speech, and trusted true communications more than false communications (regardless of whether they were real or synthetic voices). The findings are considered in terms of datalink initiatives for future air traffic management, the importance placed on real speech R/T communications, and the need to develop more natural synthetic speech in this application area.

  7. AUTOMATED DECONVOLUTION OF COMPOSITE MASS SPECTRA OBTAINED WITH AN OPEN-AIR IONIZATIONS SOURCE BASED ON EXACT MASSES AND RELATIVE ISOTIPIC ABUNDANCES

    EPA Science Inventory

    Chemicals dispersed by accidental, deliberate, or weather-related events must be rapidly identified to assess health risks. Mass spectra from high levels of analytes obtained using rapid, open-air ionization by a Direct Analysis in Real Time (DART®) ion source often contain

  8. Factors that Alter Body Fat, Body Mass, and Fat-Free Mass in Pediatric Obesity.

    ERIC Educational Resources Information Center

    LeMura, Linda M.; Maziekas, Michael T.

    2002-01-01

    Investigated the effects of exercise programs on changes in body mass, fat-free mass, and body fat in obese children and adolescents. Research review indicated that exercise effectively helped reduce children's and adolescents' body composition variables. The most favorable body alterations occurred with low- intensity, long-duration exercise;…

  9. Operational factors of air service to small communities

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The feasibility of using 30-passenger jet aircraft to service low density, short haul markets was analyzed. Aircraft characteristics, market potential, and economic factors were among the areas evaluated.

  10. Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2012-01-01

    The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

  11. Composition of air masses in Fuerteventura (Canary Islands) according to their origins

    SciTech Connect

    Patier, R.F.; Diez Hernandez, P.; Diaz Ramiro, E.; Ballesteros, J.S.; Santos-Alves, S.G. dos

    1994-12-31

    The Centro Nacional de Sanidad Ambiental has among their duties the background atmospheric pollution monitoring in Spain. To do so, the laboratory has set up 6 field stations in the Iberian Peninsula. In these stations, both gaseous and particulate pollutants are currently analyzed. However, there is a lack of data about the atmospheric pollution in the Canary, where they are a very strong influence of natural emissions from sea and the Saharan desert, mixed with anthropogenic ones. Therefore, during the ASTEX/MAGE project the CNSA established a station in Fuerteventura island, characterized by the nonexistence of man-made emissions, to measure some atmospheric pollutants, in order to foresee their origins. In this study, the authors analyzed some pollutants that are used to obtain a clue about the sources of air masses such as gaseous ozone and metallic compounds (vanadium, iron and manganese) in the atmospheric aerosol fractionated by size.

  12. Emphysema and fibrosis: risk factors in responsiveness to air pollution

    SciTech Connect

    Costa, D.L.; Lehmann, J.R.

    1984-01-01

    Episodic and epidemiologic data appear to support the belief that chronic non-specific lung disease imposes an additional risk to affected individuals when challenged by air pollution. While this concept has been implicitly enacted into law, little knowledge or understanding of the tenets of disease-based hyper-susceptibility exists. The clinical and animal experimental data show trends, but in general, have provided little substance to defend or challenge the legitimacy of the margins of safety incorporated into the standards of the EPA regulated pollutants. As more data on so-called normal individuals are being collected, many of these safety margins appear to be eroding, thus offering little encouragement that susceptible subgroups of the population are actually being protected. 39 references, 8 tables.

  13. [Characteristics and influencing factors of air pollution in and out of the highway toll gates].

    PubMed

    Chen, Ke-Jun; Chen, Ke-Liang; Zhang, Lan-Jun; Leng, Guang-Yi

    2007-08-01

    During June and July 2003, CO, NO2, THC and PM10 were sampled at the four highway toll gates in Chongqing. Air temperature, air pressure, wind velocity and traffic flow were also monitored simultaneously. The relation between air pollution parameters and influencing factors was analyzed by applying the methods of bivariate correlation and partial correlation. As shown in the monitoring result, the outdoor average concentrations of CO and PM10 exceed indoor ones, but NO2 and THC are reverse. The average concentrations of CO and NO2 at the toll gates don't exceed the indoor and outdoor air quality standards except for the toll gate in Chongqing and Chayuan. One-hour average concentrations of outdoor and indoor THC are 7.728 mg/m3 and 7.216 mg/m3 respectively, and exceed ten times of the indoor air quality standard. One-hour average concentrations of indoor and outdoor PM10 change acutely respectively, and the their maximum concentrations are 0.631 mg/m3 and 0.217 mg/m3 which exceed indoor air quality standard and the second class of ambient air quality standard. Polluting state of Chongqing toll is the worst among the four sampled tolls, and three indexes are bigger than others. Indoor and outdoor air pollutants have correlativity. Correlations of CO, PM10 and NO2 are significant at the 0.01 level respectively, and correlations between indoor and outdoor THC are significant at the 0.05 level. In the influencing factors analysis, traffic flow is significantly correlative with NO2, THC and PM10 (p < 0.01 or 0.01 < p < 0.05), and not significantly correlative with CO (p > 0.01). Air pressure and ambient temperature are predominating factors which influencing the concentration variation, and wind speed is a minor meteorological factor influencing the fluctuations of the data.

  14. A Comparison of Two Methods for Initiating Air Mass Back Trajectories

    NASA Astrophysics Data System (ADS)

    Putman, A.; Posmentier, E. S.; Faiia, A. M.; Sonder, L. J.; Feng, X.

    2014-12-01

    Lagrangian air mass tracking programs in back cast mode are a powerful tool for estimating the water vapor source of precipitation events. The altitudes above the precipitation site where particle's back trajectories begin influences the source estimation. We assume that precipitation comes from water vapor in condensing regions of the air column, so particles are placed in proportion to an estimated condensation profile. We compare two methods for estimating where condensation occurs and the resulting evaporation sites for 63 events at Barrow, AK. The first method (M1) uses measurements from a 35 GHz vertically resolved cloud radar (MMCR), and algorithms developed by Zhao and Garrett1 to calculate precipitation rate. The second method (M2) uses the Global Data Assimilation System reanalysis data in a lofting model. We assess how accurately M2, developed for global coverage, will perform in absence of direct cloud observations. Results from the two methods are statistically similar. The mean particle height estimated by M2 is, on average, 695 m (s.d. = 1800 m) higher than M1. The corresponding average vapor source estimated by M2 is 1.5⁰ (s.d. = 5.4⁰) south of M1. In addition, vapor sources for M2 relative to M1 have ocean surface temperatures averaging 1.1⁰C (s.d. = 3.5⁰C) warmer, and reported ocean surface relative humidities 0.31% (s.d. = 6.1%) drier. All biases except the latter are statistically significant (p = 0.02 for each). Results were skewed by events where M2 estimated very high altitudes of condensation. When M2 produced an average particle height less than 5000 m (89% of events), M2 estimated mean particle heights 76 m (s.d. = 741 m) higher than M1, corresponding to a vapor source 0.54⁰ (s.d. = 4.2⁰) south of M1. The ocean surface at the vapor source was an average of 0.35⁰C (s.d. = 2.35⁰C) warmer and ocean surface relative humidities were 0.02% (s.d. = 5.5%) wetter. None of the biases was statistically significant. If the vapor source

  15. Factors Affecting Parent's Perception on Air Quality-From the Individual to the Community Level.

    PubMed

    Guo, Yulin; Liu, Fengfeng; Lu, Yuanan; Mao, Zongfu; Lu, Hanson; Wu, Yanyan; Chu, Yuanyuan; Yu, Lichen; Liu, Yisi; Ren, Meng; Li, Na; Chen, Xi; Xiang, Hao

    2016-05-12

    The perception of air quality significantly affects the acceptance of the public of the government's environmental policies. The aim of this research is to explore the relationship between the perception of the air quality of parents and scientific monitoring data and to analyze the factors that affect parents' perceptions. Scientific data of air quality were obtained from Wuhan's environmental condition reports. One thousand parents were investigated for their knowledge and perception of air quality. Scientific data show that the air quality of Wuhan follows an improving trend in general, while most participants believed that the air quality of Wuhan has deteriorated, which indicates a significant difference between public perception and reality. On the individual level, respondents with an age of 40 or above (40 or above: OR = 3.252; 95% CI: 1.170-9.040), a higher educational level (college and above: OR = 7.598; 95% CI: 2.244-25.732) or children with poor healthy conditions (poor: OR = 6.864; 95% CI: 2.212-21.302) have much more negative perception of air quality. On the community level, industrial facilities, vehicles and city construction have major effects on parents' perception of air quality. Our investigation provides baseline information for environmental policy researchers and makers regarding the public's perception and expectation of air quality and the benefits to the environmental policy completing and enforcing.

  16. Effect Measure Modification of Blood Lead-Air Lead Slope Factors

    EPA Science Inventory

    Background: There is abundant literature finding that blood lead (PbB) levels are directly influenced by susceptibility factors including race and ethnicity, age, and housing. However, no study has explored how susceptibility factors influence the PbB-air lead (PbA) relationship...

  17. EFFECT MEASURE MODIFICATION OF BLOOD LEAD-AIR LEAD SLOPE FACTORS

    EPA Science Inventory

    Background: There is abundant literature finding that blood lead (PbB) levels are directly influenced by susceptibility factors including race and ethnicity, age, and housing. However, no study has explored how susceptibility factors influence the PbB-air lead (PbA) relationship...

  18. Mitigating factors on air concentrations of radon emanating from different granite samples

    SciTech Connect

    Qari, T.M.; Mamoon, A.M.; Abdul-Fattah, A.F. )

    1991-11-01

    Continuous exposure to increased air concentrations of radon in living areas is to be avoided according to the Environmental Protection Agency (EPA) and several published reports. Radon concentrations in ambient air are influenced by several factors related to the nature of the radon source itself, environmental conditions, and the presence of mitigating factors, if any. In this study, crushed granite samples of different types, particle diameters, and moisture contents were compared in simplified test systems with regard to radon emanation from the samples. The effects of selected mitigating factors, namely, ventilation and different barriers to diffusion of emanated radon were determined.

  19. Study Case of Air-Mass Modification over Poland and Romania Observed by the Means of Multiwavelength Raman Depolarization Lidars

    NASA Astrophysics Data System (ADS)

    Costa-Surós, Montserrat; Janicka, Lucja; Stachlewska, Iwona S.; Nemuc, Anca; Talianu, Camelia; Heese, Birgit; Engelmann, Ronny

    2016-06-01

    An air-mass modification, on its way from Poland to Romania, observed between 19-21 July 2014 is discussed. The air-mass was investigated using data of two multi-wavelength lidars capable of performing regular elastic, depolarization and Raman measurements in Warsaw, Poland, and in Magurele, Romania. The analysis was focused on evaluating optical properties of aerosol in order to search for similarities and differences in the vertical profiles describing the atmospheric layers above the two stations within given period.

  20. Large-scale transport of a CO-enhanced air mass from Europe to the Middle East

    NASA Technical Reports Server (NTRS)

    Connors, V. S.; Miles, T.; Reichle, H. G., Jr.

    1989-01-01

    On November 14, 1981, the shuttle-borne Measurement of Air Pollution from Satellites (MAPS) experiment observed a carbon monoxide (CO) enhanced air mass in the middle troposphere over the Middle East. The primary source of this polluted air was estimated by constructing adiabatic isentropic trajectories backwards from the MAPS measurement location over a 36 h period. The isentropic diagnostics indicate that CO-enhanced air was transported southeastward over the Mediterranean from an organized synoptic-scale weather regime, albeit of moderate intensity, influencing central Europe on November 12. Examination of the evolving synoptic scale vertical velocity and precipitation patterns during this period, in conjuction with Meteosat visible, infrared, and water vapor imagery, suggests that the presence of this disturbed weather system over Europe may have created upward transport of CO-enhanced air between the boundary-layer and midtropospheric levels, and subsequent entrainment in the large-scale northwesterly jet stream flow over Europe and the Mediterranean.

  1. Recent trends of persistent organic pollutants in air in central Europe - Air monitoring in combination with air mass trajectory statistics as a tool to study the effectivity of regional chemical policy

    NASA Astrophysics Data System (ADS)

    Dvorská, A.; Lammel, G.; Holoubek, I.

    We use air mass back trajectory analysis of persistent organic pollutant (POP) levels monitored at a regional background site, Košetice, Czech Republic, as a tool to study the effectiveness of emission reduction measures taken in the last decade in the region. The representativity of the chosen trajectory starting height for air sampling near ground was ensured by excluding trajectories starting at time of inversions lower than their starting height. As the relevant pollutant sources are exclusively located in the atmospheric boundary layer, trajectory segments above this layer were also excluded from the analysis. We used a linear time weight to account for the influence of dispersion and deposition on trace components abundances and to quantify the ground source loading, a continuous measure for the influence of surface emissions. Hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), DDT, and two time periods, the years 1997-1999 and 2004-2006, were studied. The pollutant levels transported to Košetice decreased for all substances except HCB. Except for lindane seasonal emissions were insignificant. Increasing emissions of HCB were at least partly linked to the 2002 floods in the Danube basin. Major emissions of 1997-1999 which decreased significantly were in France (lindane), western Poland, Hungary and northern ex-Yugoslavia (technical HCH), and the Czech Republic (DDT). Emissions remaining in 2004-2006 include HCB and DDT in the northern Czech Republic, HCB and PCBs in Germany. Besides changes in emission strength meteorological factors influence the level of transported pollutant concentrations. The prevailing air flow pattern limits the geographic coverage of this analysis to central Europe and parts of western Europe. However, no POP monitoring stations exist in areas suitable for a possible extension of the study area.

  2. Numerical Simulation of Air Mass Modification Over the East China Sea during the Winter Season

    NASA Astrophysics Data System (ADS)

    Hsu, Wu-Ron

    Air mass modification over the East China Sea during cold air outbreaks in the winter season was simulated by utilizing a high-resolution numerical model. The model includes most of the major physical processes, such as, surface exchange of heat and moisture between water and air; condensation and evaporation; and vertical turbulent transfer of heat, moisture, and momentum. The simulated convective boundary layer (CBL) consists of a surface layer, a subcloud layer, and a cloud layer. It is capped by an inversion with strong temperature and moisture gradients. Mesoscale cellular convection (MCC) embedded within the convective layer moves along with the mean wind. The average aspect ratio of the cells is 17.5, which agrees with observed aspect ratios for convective cells over the East China Sea. The upward convective motion correlates very well with the appearance of clouds, higher temperature, and higher moisture content in the CBL. The effects of diabatic heating were found to be very important in driving the thermal convection. Without the release of latent heat, the convective layer would be very shallow, and the convective motion would be greatly suppressed. Even though the formulation and dissipation of a cloud is associated with the movement of the resolvable scale MCC, the vertical transport of heat and moisture is achieved mainly by the unresolvable turbulent eddies. The distribution of specific humidity during the passage of the surface front reveals the moisture being pushed upward along the frontal surface as observed. The cold and dry air behind the cold front is quickly modified by strong convection over the warm water surface, especially over the Kuroshio Current. A cloud-free region exists near the coast where the CBL is too shallow for clouds to develop. A layer of stratocumulus forms downstream from the cloud-free region. The depth of the CBL increases toward the Kuroshio Current due to strong heat and moisture fluxes from the water surface. The CBL

  3. 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.

  4. Air/water subchannel measurements of the equilibrium quality and mass-flux distribution in a rod bundle. [BWR

    SciTech Connect

    Sterner, R.W.; Lahey, R.T. Jr.

    1983-07-01

    Subchannel measurements were performed in order to determine the equilibrium quality and mass flux distribution in a four rod bundle, using air/water flow. An isokinetic technique was used to sample the flow in the center, side and corner subchannels of this test section. Flow rates of the air and water in each sampled subchannel were measured. Experiments were performed for two test-section-average mass fluxes (0.333x10/sup 6/ and 0.666x10/sup 6/ lb/sub m//h-ft/sup 2/), and the test-section-average quality was varied from 0% to 0.54% for each mass flux. Single-phase liquid, bubbly, slug and churn-turbulent two-phase flow regimes were achieved. The observed data trends agreed with previous diabatic measurements in which the center subchannel had the highest quality and mass flux, while the corner subchannel had the lowest.

  5. A Distributed Simulation Facility to Support Human Factors Research in Advanced Air Transportation Technology

    NASA Technical Reports Server (NTRS)

    Amonlirdviman, Keith; Farley, Todd C.; Hansman, R. John, Jr.; Ladik, John F.; Sherer, Dana Z.

    1998-01-01

    A distributed real-time simulation of the civil air traffic environment developed to support human factors research in advanced air transportation technology is presented. The distributed environment is based on a custom simulation architecture designed for simplicity and flexibility in human experiments. Standard Internet protocols are used to create the distributed environment, linking all advanced cockpit simulator, all Air Traffic Control simulator, and a pseudo-aircraft control and simulation management station. The pseudo-aircraft control station also functions as a scenario design tool for coordinating human factors experiments. This station incorporates a pseudo-pilot interface designed to reduce workload for human operators piloting multiple aircraft simultaneously in real time. The application of this distributed simulation facility to support a study of the effect of shared information (via air-ground datalink) on pilot/controller shared situation awareness and re-route negotiation is also presented.

  6. Cockpit Resource Management (CRM) and human factors training: What Air New Zealand is doing about it

    NASA Technical Reports Server (NTRS)

    Scott-Milligan, Fionna; Wyness, Bryan

    1987-01-01

    The authors have played an integral role in Air New Zealand's evaluation of CRM and Human Factors training options available to date. As the final decision as to which course is best suited to Air New Zealand's needs has yet to be made, briefly outlined are: (1) why this form of training was considered necessary; (2) the approach taken to evaluating the options available; (3) some of the problems encountered on the way; and (4) some plans for the future.

  7. Diffusion of Innovation: Factors Promoting Interest in Solar Photovoltaic Generation Systems Within Air Force Installations

    DTIC Science & Technology

    2007-03-01

    Q42c. How likely is it that your base will request funding in these systems in the next 10 years? (large scale) Q43a.How beneficial do you think it...DIFFUSION OF INNOVATION: FACTORS PROMOTING INTEREST IN SOLAR PHOTOVOLTAIC GENERATION SYSTEMS WITHIN AIR...SOLAR PHOTOVOLTAIC GENERATION SYSTEMS WITHIN AIR FORCE INSTALLATIONS THESIS Presented to the Faculty Department of Systems and Engineering

  8. U.S. Civil Air Show Crashes, 1993 to 2013: Burden, Fatal Risk Factors, and Evaluation of a Risk Index for Aviation Crashes.

    PubMed

    Ballard, Sarah-Blythe; Osorio, Victor B

    2015-01-01

    This study provides new public health data about U.S. civil air shows. Risk factors for fatalities in civil air show crashes were analyzed. The value of the FIA score in predicting fatal outcomes was evaluated. With the use of the FAA's General Aviation and Air Taxi Survey and the National Transportation Safety Board's data, the incidence of civil air show crashes from 1993 to 2013 was calculated. Fatality risk factors for crashes were analyzed by means of regression methods. The FIA index was validated to predict fatal outcomes by using the factors of fire, instrument conditions, and away-from-airport location, and was evaluated through receiver operating characteristic (ROC) curves. The civil air show crash rate was 31 crashes per 1,000 civil air events. Of the 174 civil air show crashes that occurred during the study period, 91 (52%) involved at least one fatality; on average, 1.1 people died per fatal crash. Fatalities were associated with four major risk factors: fire [adjusted odds ratio (AOR) = 7.1, 95% confidence interval (CI) = 2.4 to 20.6, P < .001], pilot error (AOR = 5.2, 95% CI = 1.8 to 14.5, P = .002), aerobatic flight (AOR = 3.6, 95% CI = 1.6 to 8.2, P = .002), and off-airport location (AOR = 3.4, 95% CI = 1.5 to 7.5, P = .003). The area under the FIA score's ROC curve was 0.71 (95% CI = 0.64 to 0.78). Civil air show crashes were marked by a high risk of fatal outcomes to pilots in aerobatic performances but rare mass casualties. The FIA score was not a valid measurement of fatal risk in civil air show crashes.

  9. Hamilton study: distribution of factors confounding the relationship between air quality and respiratory health

    SciTech Connect

    Pengelly, L.D.; Kerigan, A.T.; Goldsmith, C.H.; Inman, E.M.

    1984-10-01

    Hamilton, Ontario is an industrial city with a population of 300,000 which is situated at the western end of Lake Ontario. Canada's two largest iron and steel mills are located here; the city historically has had relatively poor air quality, which has improved markedly in the last 25 years. Concern about the health effects of current air quality recently led us to carry out an epidemiological study of the effects of air pollution on the respiratory health of over 3500 school children. Respiratory health was measured by pulmonary function testing of each child, and by an assessment of each child's respiratory symptoms via a questionnaire administered to the parents. Previous studies had shown that other environmental factors (e.g. parental smoking, parental cough, socioeconomic level, housing, and gas cooking) might also affect respiratory health, and thus confound any potential relationships between health and air pollution. The questionnaire also collected information on many of these confounding factors. For the purposes of initial analysis, the city was divided into five areas in which differences in air quality were expected. In general, factors which have been associated with poor respiratory health were observed to be more prevalent in areas of poorer air quality.

  10. Ambient air quality trends and driving factor analysis in Beijing, 1983-2007.

    PubMed

    Zhang, Ju; Ouyang, Zhiyun; Miao, Hong; Wang, Xiaoke

    2011-01-01

    The rapid development in Beijing, the capital of China, has resulted in serious air pollution problems. Meanwhile great efforts have been made to improve the air quality, especially since 1998. The variation in air quality under the interaction of pollution and control in this mega city has attracted much attention. We analyzed the changes in ambient air quality in Beijing since the 1980's using the Daniel trend test based on data from long-term monitoring stations. The results showed that different pollutants displayed three trends: a decreasing trend, an increasing trend and a flat trend. SO2, dustfall, B[a]P, NO2 and PM10 fit decreasing trend pattern, while NOx showed an increasing trend, and CO, ozone pollution, total suspended particulate (TSP), as well as Pb fit the flat trend. The cause of the general air pollution in Beijing has changed from being predominantly related to coal burning to mixed traffic exhaust and coal burning related pollution. Seasonally, the pollution level is typically higher during the heating season from November to the following March. The interaction between pollution sources change and implementation of air pollution control measures was the main driving factor that caused the variation in air quality. Changes of industrial structure and improved energy efficiency, the use of clean energy and preferred use of clean coal, reduction in pollution sources, and implementation of advanced environmental standards have all contributed to the reduction in air pollution, particularly since 1998.

  11. Investigation of earthquake factor for optimum tuned mass dampers

    NASA Astrophysics Data System (ADS)

    Nigdeli, Sinan Melih; Bekdaş, Gebrail

    2012-09-01

    In this study the optimum parameters of tuned mass dampers (TMD) are investigated under earthquake excitations. An optimization strategy was carried out by using the Harmony Search (HS) algorithm. HS is a metaheuristic method which is inspired from the nature of musical performances. In addition to the HS algorithm, the results of the optimization objective are compared with the results of the other documented method and the corresponding results are eliminated. In that case, the best optimum results are obtained. During the optimization, the optimum TMD parameters were searched for single degree of freedom (SDOF) structure models with different periods. The optimization was done for different earthquakes separately and the results were compared.

  12. Optimization of solar cells for air mass zero operation and a study of solar cells at high temperatures, phase 3

    NASA Technical Reports Server (NTRS)

    Blakeslee, A. E.; Hovel, H. J.; Woodall, J. M.

    1977-01-01

    The etch-back epitaxy process is described for producing thin, graded composition GaAlAs layers. The palladium-aluminum contact system is discussed along with its associated problems. Recent solar cell results under simulated air mass zero light and at elevated temperatures are reported and the growth of thin polycrystalline GaAs films on foreign substrates is developed.

  13. On the association between daily mortality and air mass types in Athens, Greece during winter and summer.

    PubMed

    Kassomenos, Pavlos A; Gryparis, Alexandros; Katsouyanni, Klea

    2007-03-01

    In this study, we examined the short-term effects of air mass types on mortality in Athens, Greece. An objective air mass types classification was used, based on meteorological parameters measured at the surface. Mortality data were treated with generalized additive models (GAM) and extending Poisson regression, using a LOESS smoother to control for the confounding effects of seasonal patterns, adjusting also for temperature, long-term trends, day of the week, and ambient particle concentrations. The introduced air mass classification explains the daily variation of mortality to a statistically significant degree. The highest daily mortality was observed on days characterized by southerly flow conditions for both the cold (increase in relative risk for mortality 9%; with a 95% confidence interval: 3-14%), and the warm period (7%; with a 95% confidence interval: 2-13%) of the year. The northeasterly flow is associated with the lowest mortality. Effects on mortality, independent of temperature, are observed mainly for lag 0 during the cold period, but persist longer during the warm period. Not adjusting for temperature and/or ambient particle levels slightly alters the results, which then reflect the known temperature and particle effects, already reported in the literature. In conclusion, we find that air mass types have independent effects on mortality for both the cold and warm season and may be used to predict weather-related adverse health effects.

  14. The Influence of Declining Air Lead Levels on Blood Lead–Air Lead Slope Factors in Children

    PubMed Central

    Richmond-Bryant, Jennifer; Davis, Allen; Cohen, Jonathan; Lu, Shou-En; Svendsgaard, David; Brown, James S.; Tuttle, Lauren; Hubbard, Heidi; Rice, Joann; Kirrane, Ellen; Vinikoor-Imler, Lisa C.; Kotchmar, Dennis; Hines, Erin P.; Ross, Mary

    2014-01-01

    Background: It is difficult to discern the proportion of blood lead (PbB) attributable to ambient air lead (PbA), given the multitude of lead (Pb) sources and pathways of exposure. The PbB–PbA relationship has previously been evaluated across populations. This relationship was a central consideration in the 2008 review of the Pb national ambient air quality standards. Objectives: The objectives of this study were to evaluate the relationship between PbB and PbA concentrations among children nationwide for recent years and to compare the relationship with those obtained from other studies in the literature. Methods: We merged participant-level data for PbB from the National Health and Nutrition Examination Survey (NHANES) III (1988–1994) and NHANES 9908 (1999–2008) with PbA data from the U.S. Environmental Protection Agency. We applied mixed-effects models, and we computed slope factor, d[PbB]/d[PbA] or the change in PbB per unit change in PbA, from the model results to assess the relationship between PbB and PbA. Results: Comparing the NHANES regression results with those from the literature shows that slope factor increased with decreasing PbA among children 0–11 years of age. Conclusion: These findings suggest that a larger relative public health benefit may be derived among children from decreases in PbA at low PbA exposures. Simultaneous declines in Pb from other sources, changes in PbA sampling uncertainties over time largely related to changes in the size distribution of Pb-bearing particulate matter, and limitations regarding sampling size and exposure error may contribute to the variability in slope factor observed across peer-reviewed studies. Citation: Richmond-Bryant J, Meng Q, Davis A, Cohen J, Lu SE, Svendsgaard D, Brown JS, Tuttle L, Hubbard H, Rice J, Kirrane E, Vinikoor-Imler LC, Kotchmar D, Hines EP, Ross M. 2014. The Influence of declining air lead levels on blood lead–air lead slope factors in children. Environ Health Perspect 122:754

  15. PM2.5 chemical composition at a rural background site in Central Europe, including correlation and air mass back trajectory analysis

    NASA Astrophysics Data System (ADS)

    Schwarz, Jaroslav; Cusack, Michael; Karban, Jindřich; Chalupníčková, Eva; Havránek, Vladimír; Smolík, Jiří; Ždímal, Vladimír

    2016-07-01

    PM2.5 mass concentrations and chemical compositions sampled over a 13-month period at a Central European rural background site (Košetice) are presented in this work. A comprehensive chemical analysis of PM2.5 was performed, which provided elemental composition (Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, and Pb) and the concentration of water-soluble inorganic anions (SO42 -, NO3-. Cl-, NO2-, Br-, and H2PO4-) and cations (Na+, NH4+, K+, Ca2 +, and Mg2 +), elemental and organic carbon (EC and OC), and levoglucosan. Spearman correlation coefficients between individual chemical species and particle number concentrations were calculated for the following six size ranges: 10-25 nm (N10-25), 25-50 nm (N25-50), 50-80 nm (N50-80), 80-150 nm (N80-150), 150-300 nm (N150-300), and 300-800 nm (N300-800). Average concentrations of individual species were comparable with concentrations reported from similar sites across Central Europe. Organic matter (OM) accounted for 45% of the PM2.5 mass (calculated from OC by a factor of 1.6), while the second most common component were secondary aerosols (SO42 -: 19%, NO3-: 14%, NH4+: 10%), which accounted for 43% of the mass. Based on levoglucosan analysis, 31% of OM was attributed to emissions associated with biomass burning (OMBB). EC concentrations, determined using the EUSAAR_2 thermal optical protocol, contributed 4% to PM2.5 mass. A total of 1% of the mass was attributed to a mineral matter source, while the remaining 6% was from an undetermined mass. Seasonal variations showed highest concentrations of NO3- and OMBB in winter, nitrate share in spring, and an increase in percentage of SO42 - and mineral matter in summer. The largest seasonal variation was found for species associated with wood and coal combustion (levoglucosan, K+, Zn, Pb, As), which had clear maxima during winter. Correlation analysis of different size fraction particle number concentrations was used to distinguish the influence

  16. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    NASA Astrophysics Data System (ADS)

    Hoseeinzadeh, Sepideh; Gorji-Bandpy, Mofid

    2012-04-01

    This paper presents a computational fluid dynamics (CFD) calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  17. Political Factors Affecting the Enactment of State-Level Clean Indoor Air Laws

    PubMed Central

    Vernick, Jon S.; Stuart, Elizabeth A.; Webster, Daniel W.

    2014-01-01

    Objectives. We examined the effects of key political institutional factors on the advancement of state-level clean indoor air laws. Methods. We performed an observational study of state-level clean indoor air law enactment among all 50 US states from 1993 to 2010 by using extended Cox hazard models to assess risk of enacting a relevant law. Results. During the 18-year period from 1993 to 2010, 28 states passed a law covering workplaces, 33 states passed a law covering restaurants, 29 states passed a law covering bars, and 16 states passed a law covering gaming facilities. States with term limits had a 2.15 times greater hazard (95% confidence interval [CI] = 1.27, 3.65; P = .005) of enacting clean indoor air laws. The presence of state-level preemption of local clean indoor air laws was associated with a 3.26 times greater hazard (95% CI = 1.11, 9.53; P = .031) of state-level policy enactment. In the presence of preemption, increased legislative professionalism was strongly associated (hazard ratio = 3.28; 95% CI = 1.10, 9.75; P = .033) with clean indoor air law enactment. Conclusions. Political institutional factors do influence state-level clean indoor air law enactment and may be relevant to other public health policy areas. PMID:24825239

  18. Background NO/sub x/ mixing ratios in air masses over the North Atlantic ocean

    SciTech Connect

    Helas, G.; Warneck, P.

    1981-08-20

    A chemiluminescence analyzer was used to measure NO/sub x/ mixing ratios at the west coast of Ireland. Two measurement modes allowed the determination of NO and NO/sub x/ = NO+NO/sub 2/. In a third mode using a molybdenum converter, higher signals were observed than was in the second mode indicating that nitrogen compounds other than NO+NO/sub 2/ are registered. They are denoted 'excess NO/sub x/'. The average NO/sub 2/ mixing ratio for a week period was 101 +- 87 pptv. In pure marine air masses identified by means of trajectory calculations, the NO/sub 2/ mixing ratios were lower and exhibited in addition a diurnal variation with nighttime values of 37 +- 6 pptv and average values of 87 +- 47 pptv. Possible origins of the diurnal variation are discussed. For such conditions, the NO mixing ratio generally was unmeasurably small, certainly less than 10 pptv. The excess NO/sub x/ is also higher during the day compared with nighttime values of about 70 pptv. Further studies are required to identify the compounds involved.

  19. Variations of the glacio-marine air mass front in West Greenland through water vapor isotopes

    NASA Astrophysics Data System (ADS)

    Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.

    2012-12-01

    While the isotopic distribution of precipitation has been widely used for research in hydrology, paleoclimatology, and ecology for decades, intensive isotopic studies of atmospheric water vapor has only recently been made possible by spectral-based technology. New instrumentation based on this technology opens up many opportunities to investigate short-term atmospheric dynamics involving the water cycle and moisture transport. We deployed a Los Gatos Water Vapor Isotope Analyzer (WVIA) at Kangerlussuaq, Greenland from July 21 to August 15, and measured the water vapor concentration and its isotopic ratios continuously at 10s intervals. A Danish Meteorological Institute site is located about 1 km from the site of the deployment, and meteorological data is collected at 30 min intervals. During the observation period, the vapor concentration of the ambient air ranges from 5608.4 to 11189.4 ppm; dD and d18O range from -254.5 to -177.7 ‰ and -34.2 to -23.2 ‰, respectively. The vapor content (dew point) and the isotopic ratios are both strongly controlled by the wind direction. The easterly winds are associated with dry, isotopically depleted air masses formed over the glacier, while westerly winds are associated with moist and isotopically enriched air masses from the marine/fjord surface. This region typically experiences katabatic winds off of the ice sheet to the east. However, during some afternoons, the wind shifts 180 degrees, blowing off the fjord to the west. This wind switch marks the onset of a sea breeze, and significant isotopic enrichment results. Enrichment in deuterium is up to 60 ‰ with a mean of 15‰, and oxygen-18 is enriched by 3‰ on average and up to 8 ‰. Other afternoons have no change in wind, and only small changes in humidity and vapor isotopic ratios. The humidity and isotopic variations suggest the local atmosphere circulation is dominated by relatively high-pressure systems above the cold glaciers and cool sea surface, and diurnal

  20. US Commercial Air Tour Crashes, 2000–2011: Burden, Fatal Risk Factors, and FIA Score Validation

    PubMed Central

    Ballard, Sarah-Blythe; Beaty, Leland P.; Baker, Susan P.

    2013-01-01

    Introduction This study provides new public health data concerning the US commercial air tour industry. Risk factors for fatality in air tour crashes were analyzed to determine the value of the FIA score in predicting fatal outcomes. Methods Using the Federal Aviation Administration’s (FAA) General Aviation and Air Taxi Survey and National Transportation Safety Board data, the incidence of commercial air tour crashes from 2000 through 2010 was calculated. Fatality risk factors for crashes occurring from 2000 through 2011 were analyzed using regression methods. The FIA score, Li and Baker’s fatality risk index, was validated using receiver operating characteristic (ROC) curves. Results The industry-wide commercial air tour crash rate was 2.7 per 100,000 flight hours. The incidence rates of Part 91 and 135 commercial air tour crashes were 3.4 and 2.3 per 100,000 flight hours, respectively (relative risk [RR] 1.5, 95% confidence interval [CI] 1.1–2.1, P=0.015). Of the 152 air tour crashes that occurred from 2000 through 2011, 30 (20%) involved at least one fatality and, on average, 3.5 people died per fatal crash. Fatalities were associated with three major risk factors: fire (Adjusted odds ratio [AOR] 5.1, 95% CI 1.5–16.7, P=0.008), instrument meteorological conditions (AOR 5.4, 95% CI 1.1–26.4, P=0.038), and off-airport location (AOR 7.2, 95% CI 1.6–33.2, P=0.011). The area under the FIA Score’s ROC curve was 0.79 (95% CI 0.71–0.88). Discussion Commercial air tour crash rates were high relative to similar commercial aviation operations. Disparities between Part 91 and 135 air tour crash rates reflect regulatory disparities that require FAA action. The FIA Score appeared to be a valid measurement of fatal risk in air tour crashes. The FIA should prioritize interventions that address the three major risk factors identified by this study. PMID:23631935

  1. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m < altitudes < 3450 m) with what was observed at the closest lowland location. The vertical distribution of 137Cs peak level was not uniform even after a long travel time/distance from Japan. This being true at least in the atmospheric boundary layer and in the lower free troposphere. Moreover the relation '137Csmax vs. altitude' shows a decreasing trend (Fig. 2). Results and discussion : Comparison of 137Cs and 7Be levels shows simultaneous increases at least when the 137Cs airborne level rose for the first time (Fig. 3). Zugspitze and Jungfraujoch stations attest of a time shift between 7Be and 137Cs peak that can be due to the particular dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground

  2. Improvement of vibration energy harvesters mechanical Q-factor through high density proof mass integration

    NASA Astrophysics Data System (ADS)

    Dompierre, A.; Fréchette, L. G.

    2016-11-01

    This paper reports on improvement of the mechanical Q-factor of resonant energy harvesters at ambient pressure via the use of tungsten proof masses by evaluating the impact of the mass size and density on the squeeze film damping. To this end, a simplified model is first proposed to evaluate cantilever beams deflection and the resulting fluid pressure build up between the mass and a near surface. The model, which accounts for simultaneous transverse and rotational motion of very long tip masses as well as for 2D fluid flow in the gap, is used to extract a scaling law for the device fluidic Q-factor Qf. This law states that Qf can be improved by either increasing the linear mass density of the tip mass or by reducing the side lengths compared to the gap height. The first approach is validated experimentally by adding a tungsten proof mass on a silicon based device and observing an improvement of the Q-factor by 103%, going from 430 to 871, while the resonance frequency drops from 457 to 127 Hz. In terms of fluidic Q-factor, this represents an increase from 562 to 1673. These results successfully demonstrate the benefits of integrating a tungsten mass to reduce the fluid losses while potentially reducing the device footprint.

  3. Air gap sparkover and gap factors: Analysis of published data. Final report

    SciTech Connect

    Gela, G.

    1994-12-01

    This report is an account of a literature search on air gap sparkover which was conducted as part of the Live Working 2000 project. The objective of this literature search was to locate and analyze published data on sparkover of air gaps which are relevant to live working. The sparkover data form the basis for determination of gap factors for live working situations. Data dating back to 1930`s were located in published papers and reports, extracted and analyzed for a variety of air gaps, including: rod-to-plane, rod-to-rod, sphere-to-plane, bundle-to-plane, hoop-to-plane, bundle-to-tower window, bundle-to-tower outside phase, and worker-to-tower air gap. The rod-to-plane air gap has been analyzed extensively in the literature, and several accurate empirical formulae have been developed to calculate the 50% sparkover voltage of the gap when subjected to transient overvoltages with the critical wave shape. The terms, such as gap factor, transient overvoltage (TOV), critical wave shape, and other relevant terms, are defined in this report for completeness. The CRIEPI formula is used as the reference in this report, since this formula has been adopted by several technical organizations (IEC, IEEE). Comparisons are also made with the second popular formula, the Gallet formula. All sparkover data obtained from the literature are presented in tables and graphs. In addition, where applicable and available, data for the critical wave shape are identified and placed in separate tables for ready reference. The calculated gap factors are based on the CRIEPI formula. Detailed comparisons of the CRIEPI and the Gallet formulae allow easy determination of the gap factors based on the Gallet formula, should one desire to compute these numbers. The calculated gap factors are summarized in tables and compared with the gap factor values tentatively suggested for use by IEC TC 78 WG 10.

  4. [FACTORS WHICH INFLUENCE THE LEAN MASS LOSS IN CANCER PATIENTS].

    PubMed

    Sánchez Sánchez, Eduardo; Muñoz Alferez, Maria José

    2015-10-01

    Introducción: el cáncer es una enfermedad de gran importancia sanitaria debido a las consecuencias físicas y funcionales que conlleva. Entre estas consecuencias está la desnutrición, que puede provocar una pérdida de masa magra y con ello una disminución de la calidad de vida, aumento de las estancias hospitalarias, costes sanitarios, etc. El objetivo de este estudio es conocer qué factores influyen en la pérdida de masa magra. Material y métodos: se trata de un estudio transversal en una muestra de 72 pacientes que reciben tratamiento radioterápico con finalidad curativa en un período comprendido entre el 7 de febrero y el 14 de mayo de 2014. Resultados: del total de pacientes se estudiaron 64, de los cuales el 43,7% presentan pérdida de masa magra, siendo el porcentaje de 21,8% los pacientes que pierden < 2%, el 4,7% los que presentan una pérdida entre el 2-5% y > 5%, el 17,2% de los pacientes. De entre los factores estudiados que pueden influir en la pérdida de masa magra, solo la presencia de síntomas digestivos poseen significación estadísitca (OR = 3,3 o 6,6, según tomemos como referencia el porcentaje de pérdida). Conclusiones: el objetivo del personal sanitario que trabaja con estos pacientes de evitar las consecuencias que acompañan a la pérdida de masa magra. Por todo esto, es importante actuar antes de la aparición de síntomas digestivos, mediante la prevención de los mismos, o la aplicación precoz de una intervención nutricional individualizada.

  5. DEVELOPMENT OF AN AIR-TO-LEAF VAPOR PHASE TRANSFER FACTOR FOR DIOXINS AND FURANS

    EPA Science Inventory

    Results of an experiment in which grass was grown in a greenhouse and outdoors, and in soils of different concentration levels of dioxins and furans, were used in a modeling exercise to derive an air-to-leaf vapor phase transfer factor. The purpose of the experiment was to under...

  6. Highly sensitive determination of polycyclic aromatic hydrocarbons in ambient air dust by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction.

    PubMed

    Krupadam, Reddithota J; Bhagat, Bhagyashree; Khan, Muntazir S

    2010-08-01

    A method based on solid--phase extraction with a molecularly imprinted polymer (MIP) has been developed to determine five probable human carcinogenic polycyclic aromatic hydrocarbons (PAHs) in ambient air dust by gas chromatography-mass spectrometry (GC-MS). Molecularly imprinted poly(vinylpyridine-co-ethylene glycol dimethacrylate) was chosen as solid-phase extraction (SPE) material for PAHs. The conditions affecting extraction efficiency, for example surface properties, concentration of PAHs, and equilibration times were evaluated and optimized. Under optimum conditions, pre-concentration factors for MIP-SPE ranged between 80 and 93 for 10 mL ambient air dust leachate. PAHs recoveries from MIP-SPE after extraction from air dust were between 85% and 97% and calibration graphs of the PAHs showed a good linearity between 10 and 1000 ng L(-1) (r = 0.99). The extraction efficiency of MIP for PAHs was compared with that of commercially available SPE materials--powdered activated carbon (PAC) and polystyrene-divinylbenzene resin (XAD)--and it was shown that the extraction capacity of the MIP was better than that of the other two SPE materials. Organic matter in air dust had no effect on MIP extraction, which produced a clean extract for GC-MS analysis. The detection limit of the method proposed in this article is 0.15 ng L(-1) for benzo[a]pyrene, which is a marker molecule of air pollution. The method has been applied to the determination of probable carcinogenic PAHs in air dust of industrial zones and satisfactory results were obtained.

  7. Ozone-surface interactions: Investigations of mechanisms, kinetics, mass transport, and implications for indoor air quality

    SciTech Connect

    Morrison, Glenn Charles

    1999-12-01

    -7, 10-5, and 10-5 respectively. To understand how internal surface area influences the equivalent reaction probability of whole carpet, a model of ozone diffusion into and reaction with internal carpet components was developed. This was then used to predict apparent reaction probabilities for carpet. He combines this with a modified model of turbulent mass transfer developed by Liu, et al. to predict deposition rates and indoor ozone concentrations. The model predicts that carpet should have an equivalent reaction probability of about 10-5, matching laboratory measurements of the reaction probability. For both carpet and duct materials, surfaces become progressively quenched (aging), losing the ability to react or otherwise take up ozone. He evaluated the functional form of aging and find that the reaction probability follows a power function with respect to the cumulative uptake of ozone. To understand ozone aging of surfaces, he developed several mathematical descriptions of aging based on two different mechanisms. The observed functional form of aging is mimicked by a model which describes ozone diffusion with internal reaction in a solid. He shows that the fleecy nature of carpet materials in combination with the model of ozone diffusion below a fiber surface and internal reaction may explain the functional form and the magnitude of power function parameters observed due to ozone interactions with carpet. The ozone induced aldehyde emissions, measured from duct materials, were combined with an indoor air quality model to show that concentrations of aldehydes indoors may approach odorous levels. He shows that ducts are unlikely to be a significant sink for ozone due to the low reaction probability in combination with the short residence time of air in ducts.

  8. Urban air pollution and climate change as environmental risk factors of respiratory allergy: an update.

    PubMed

    D'Amato, G; Cecchi, L; D'Amato, M; Liccardi, G

    2010-01-01

    The incidence of allergic respiratory diseases and bronchial asthma appears to be increasing worldwide, and people living in urban areas more frequently experience these conditions than those living in rural areas. One of the several causes of the rise in morbidity associated with allergic respiratory diseases is the increased presence of outdoor air pollutants resulting from more intense energy consumption and exhaust emissions from cars and other vehicles. Urban air pollution is now a serious public health hazard. Laboratory studies confirm epidemiologic evidence that air pollution adversely affects lung function in asthmatics. Damage to airway mucous membranes and impaired mucociliary clearance caused by air pollution may facilitate access of inhaled allergens to the cells of the immune system, thus promoting sensitization of the airway. Consequently, a more severe immunoglobulin (Ig) E-mediated response to aeroallergens and airway inflammation could account for increasing prevalence of allergic respiratory diseases in polluted urban areas. The most abundant components of urban air pollution in urban areas with high levels of vehicle traffic are airborne particulate matter, nitrogen dioxide, and ozone. In addition, the earth's temperature is increasing, mainly as a result of anthropogenic factors (e.g., fossil fuel combustion and greenhouse gas emissions from energy supply, transport, industry, and agriculture), and climate change alters the concentration and distribution of air pollutants and interferes with the seasonal presence of allergenic pollens in the atmosphere by prolonging these periods.

  9. Change of microbial communities in glaciers along a transition of air masses in western China

    NASA Astrophysics Data System (ADS)

    Xiang, Shu-Rong; Chen, Yong; Shang, Tian-Cui; Jing, Ze-Fan; Wu, Guangjian

    2010-12-01

    Microbial community dynamics across glaciers in different climatic zones provide important information about the sources, transportation pathways, and deposition of microorganisms. To better understand the possible driving forces of microbial community shifts in glacier ice at a large spatial scale, 16S rRNA gene amplification was used to establish clone libraries containing 95 bacterial sequences from three different habitats in the Qiangyong Gacier in 2005. The libraries were used in phylogenetic comparison with 149 previously reported sequences from the surface samples collected from the Kuytun 51, and East Rongbuk glaciers in the same year. The results showed the presence of cosmopolitan and endemic species, and displayed a tendency of zonal distribution of bacterial communities at genera and community levels, corresponding to the geographic placement of the three glaciers. Data also showed a significant difference in the proportion of dominant phylogenetic groups in the three glaciers. Comamonadaceae/Polaromonas (Betaproteobacteria) and Flexibacteraceae (Bacteroidetes) were dominant in the Qiangyong Glacier, Cyanobacteria, Comamonadaceae/Polaromonas, and Rhodoferax (Betaproteobacteria) were dominant in the Kuytun 51 Glacier, and Acinetobacteria (Gammaproteobacteria) were dominant in the Rongbuk Glacier. In conclusion, the current study provides evidence of microbial biogeography in glacier ice at both the fine lineage and whole community levels. The biogeographical patterns were generally associated with the hydrological transition over the glaciers in the northern periphery and southern part of the Tibetan plateau. This supports our hypothesis of air mass behavior being one of the main drivers determining the zonal distribution of microbial communities across the mountain glaciers in western China.

  10. Climatology of wintertime long-distance transport of surface-layer air masses arriving urban Beijing in 2001-2012

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xiang-De, XU

    2017-02-01

    In this study, the FLEXPART-WRF coupled modeling system is used to conduct 12-year Lagrangian modeling over Beijing, China, for the winters of 2001-2012. Based on large trajectory tracking ensembles, the long-range air transport properties, in terms of geographic source regions within the atmospheric planetary boundary layer (PBL) and large-scale ventilation, and its association with air quality levels were quantified from a climatological perspective. The results show the following: (1) The air masses residing in the near-surface layer over Beijing potentially originate from broader atmospheric boundary-layer regions, which cover vast areas with the backward tracking time elapsed. However, atmospheric transport from northeastern China and, to a lesser extent, from the surrounding regions of Beijing is important. (2) The evolution of air quality over Beijing is negatively correlated with large-scale ventilation conditions, particularly at a synoptic timescale. Thus, the simple but robust backward-trajectory ventilation (BV) index defined in this study could facilitate operational forecasting of severe air pollution events. (3) By comparison, the relatively short-range transport occurring over transport timescales of less than 3 days from southern and southeastern Beijing and its surrounding areas plays a vital role in the formation of severe air pollution events during the wintertime. (4) Additionally, an interannual trend analysis suggests that the geographic sources and ventilation conditions also changed, at least over the last decade, corresponding to the strength variability of the winter East Asian monsoon.

  11. Seasonal origins of air masses transported to Mount Wrangell, Alaska, and comparison with the past atmospheric dust and tritium variations in its ice core

    NASA Astrophysics Data System (ADS)

    Yasunari, T. J.; Shiraiwa, T.; Kanamori, S.; Fujii, Y.; Igarashi, M.; Yamazaki, K.; Benson, C. S.; Hondoh, T.

    2006-12-01

    The North Pacific region is subject to various climatic phenomena such as the Pacific Decadal Oscillation (PDO), the El Niño-Southern Oscillation (ENSO), and the Arctic Oscillation (AO), significantly affecting the ocean and the atmosphere. Additionally, material circulation is also very active in this region such as spring dust storms in the desert and arid regions of East Asia and forest fires in Siberia and Alaska. Understanding the complex connections among the climatic phenomena and the material circulation would help in attempts to predict future climate changes. For this subject, we drilled a 50-m ice core at the summit of Mount Wrangell, which is located near the coast of Alaska (62°162'170"162°171'N, 144°162'170"162;°171'W, and 4100-m). We analyzed dust particle number density, tritium concentration, and 171 171 171 171 170 162 171 D in the core. The ice core spanned the years from 1992 to 2002 and we finally divided the years into five parts (early-spring; late-spring; summer; fall; winter). Dust and tritium amounts varied annually and intra-annually. For further understanding of the factors on those variations, we should know the origins of the seasonal dust and tritium. Hence, we examined their origins by the calculation of everyday 10-days backward trajectory analysis from January 1992 to August 2002 with 3-D wind data of the European Center for Medium-Range Weather Forecast (ECMWF). In early spring, the air mass from East Asia increased and it also explained dust increases in springtime, although the air contribution in winter increased too. In late spring, the air mass from the stratosphere increased, and it also corresponded to the stratospheric tritium increase in the ice core. The air masses from Siberia and the North Pacific in the mid-latitude always significantly contributed to Mount Wrangell, although those maximum contributions were fall and summer, respectively. The air mass originating in the interior of Alaska and North America did

  12. Importance of air quality and related factors in the prevention of infection in orthopaedic implant surgery.

    PubMed

    Gosden, P E; MacGowan, A P; Bannister, G C

    1998-07-01

    Small numbers of organisms can cause orthopaedic implant infections, which give rise to a considerable degree of morbidity and also mortality. The periprosthetic infection rates have been shown to correlate with the number of airborne bacteria within 30 cm of the wound. This is influenced by factors such as the number of operating theatre personnel, their clothing and the type of ventilation system used. Guidance on routine bacteriological monitoring of ultraclean air theatres, based on the Department of Health document Health Technical Memorandum 2025, is discussed. Factors important in minimizing the number of postoperative implant infections such as the use of ultraclean air, ultraviolet radiation, different types of surgical clothing, prophylactic antibiotics and host-related factors are also discussed. The importance of proper scientific investigation into the effectiveness of practical preventative measures in the operating room is emphasized.

  13. Effects of meteorological factors on the composition of selected fungal spores in the air.

    PubMed

    Grinn-Gofroń, Agnieszka; Bosiacka, Beata

    The aim of the study was to determine functional relationships between composition of air spora and meteorological factors, using multivariate statistical technique: canonical correspondence analysis (CCA). Analyses were conducted for the data collected during the 4 year (2007-2010) and, in order to show the dynamics of such relationships, for each year separately. The CCA results indicated that all statistically significant variables accounted for 15.3 % of the total variance in the spore data in the 4 years. The largest amount of the total variance was explained in this period by the mean air temperature (9.2 %). The meteorological factors impacted spore composition differently in different years, when analysis was done for each year separately. The highest values of the total variance in the spore data, explained by the statistically significant variables, were found in 2010 (32.3 %), with the highest contribution of mean air temperature (23.8 %). In that year, the above-mentioned parameter had the lowest value in comparison to other years. Canonical correspondence analysis provides not only a comprehensive assessment of the impact of meteorological factors on specific spore combinations in the air, but also informative graphical presentations of the results, illustrating the correlation between the occurrence of particular spore taxa and meteorological variables.

  14. Prediction of Excess Air Factor in Automatic Feed Coal Burners by Processing of Flame Images

    NASA Astrophysics Data System (ADS)

    Talu, Muhammed Fatih; Onat, Cem; Daskin, Mahmut

    2017-03-01

    In this study, the relationship between the visual information gathered from the flame images and the excess air factor λ in coal burners is investigated. In conventional coal burners the excess air factor λ. can be obtained using very expensive air measurement instruments. The proposed method to predict λ for a specific time in the coal burners consists of three distinct and consecutive stages; a) online flame images acquisition using a CCD camera, b) extraction meaningful information (flame intensity and brightness)from flame images, and c) learning these information (image features) with ANNs and estimate λ. Six different feature extraction methods have been used: CDF of Blue Channel, Co-Occurrence Matrix, L ∞-Frobenius Norms, Radiant Energy Signal (RES), PCA and Wavelet. When compared prediction results, it has seen that the use of co-occurrence matrix with ANNs has the best performance (RMSE = 0.07) in terms of accuracy. The results show that the proposed predicting system using flame images can be preferred instead of using expensive devices to measure excess air factor in during combustion.

  15. Automatic Speech Recognition in Air Traffic Control: a Human Factors Perspective

    NASA Technical Reports Server (NTRS)

    Karlsson, Joakim

    1990-01-01

    The introduction of Automatic Speech Recognition (ASR) technology into the Air Traffic Control (ATC) system has the potential to improve overall safety and efficiency. However, because ASR technology is inherently a part of the man-machine interface between the user and the system, the human factors issues involved must be addressed. Here, some of the human factors problems are identified and related methods of investigation are presented. Research at M.I.T.'s Flight Transportation Laboratory is being conducted from a human factors perspective, focusing on intelligent parser design, presentation of feedback, error correction strategy design, and optimal choice of input modalities.

  16. Study of the Tropospheric Aerosol Structure Under Changing of the Air Mass Type from Lidar Observations in Tomsk

    NASA Astrophysics Data System (ADS)

    Samoilova, S. V.; Balin, Yu. S.; Kokhanenko, G. P.; Penner, I. É.

    2016-04-01

    The aerosol optical characteristics in the main tropospheric layers are investigated based on joint interpretation of data of multi-frequency lidar sensing (110 sessions) and results of modeling of back air mass trajectories. Methodical problems for separating layers with different scattering properties and estimating their vertical boundaries are considered. Three optical criteria are simultaneously used to distinguish aerosol layers from cloud formations, including the gradient of the backscattering coefficient, optical depth, and the depolarization ratio. High values of the lidar ratio (66 sr) and of the Angstrom exponent (1.62) in the shortwavelength spectral range are observed in the boundary layer for Arctic transport. At the same time, low values of these optical parameters are characteristic for Asian transport: the lidar ratio is 54 sr and the Angstrom exponent is 1.1, which is explained by different relative contributions of the coarse and fine aerosol fractions to the air mass.

  17. Simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters by gas chromatography-mass spectrometry

    NASA Astrophysics Data System (ADS)

    Akyüz, Mehmet

    2008-05-01

    A gas chromatography-mass spectrometry (GC-MS) method has been proposed for the simultaneous determination of aliphatic and aromatic amines in ambient air and airborne particulate matters (PMs). The method includes collection of the particulate matters (PM2.5 and PM10) using dichotomous Partisol 2025 sampler followed by extraction of the compounds into acidic solution, and pre-concentration of the compounds by percolating the air samples through the acidic solution, then ion-pair extraction of amines with bis-2-ethylhexylphosphate and derivatisation with isobutyl chloroformate prior to their GC-MS analysis in both electron impact and positive and negative ion chemical ionisation mode as their isobutyloxycarbonyl (isoBOC) derivatives. In the present study, ambient air and airborne particulate samples collected in Zonguldak province during summer and winter times of 2006-2007 were analysed for aliphatic and aromatic amines by the proposed method and the method was shown to be suitable for the simultaneous determination of these compounds at the levels of pg m-3 in air and airborne particulate samples. The seasonal distributions of bioactive amines in concentrations in ambient air and airborne PMs were evaluated as they are significant for the estimation of their effects on the environment and human health. The concentration levels of water soluble amines fluctuate significantly within a year with higher means and peak concentrations, probably due to the increased emissions from coal-fired domestic and central heating, in the winter times compared to the summer times. The results indicated that the relative amine content in particulates modulates with molecular mass and time of the year and the relative amine content especially in fine fractions of inhalable airborne particulates increases with the molecular mass of species but decreases with temperature.

  18. Calculations of relative optical air masses for various aerosol types and minor gases in Arctic and Antarctic atmospheres

    NASA Astrophysics Data System (ADS)

    Tomasi, Claudio; Petkov, Boyan H.

    2014-02-01

    The dependence functions of relative optical air mass on apparent solar zenith angle θ have been calculated over the θ < 87° range for the vertical profiles of wet-air molecular number density in the Arctic and Antarctic atmospheres, extinction coefficients of different aerosol types, and molecular number density of water vapor, ozone, nitrogen dioxide, and oxygen dimer. The calculations were made using as weight functions the seasonal average vertical profiles of (i) pressure and temperature derived from multiyear sets of radiosounding measurements performed at Ny-Ålesund, Alert, Mario Zucchelli, and Neumayer stations; (ii) volume extinction coefficients of background summer aerosol, Arctic haze, and Kasatochi and Pinatubo volcanic aerosol measured with lidars or balloon-borne samplings; and (iii) molecular number concentrations of the above minor gases, derived from radiosonde, ozonesonde, and satellite-based observations. The air mass values were determined using a formula based on a realistic atmospheric air-refraction model. They were systematically checked by comparing their mutual differences with the uncertainties arising from the seasonal and daily variations in pressure and temperature conditions within the various ranges, where aerosol and gases attenuate the solar radiation most efficiently. The results provide evidence that secant-approximated and midlatitude air mass values are inappropriate for analyzing the Sun photometer measurements performed at polar sites. They indicate that the present evaluations can be reliably used to estimate the aerosol optical depth from the Arctic and Antarctic measurements of total optical depth, after appropriate corrections for the Rayleigh scattering and gaseous absorption optical depths.

  19. Screening for sarin in air and water by solid-phase microextraction-gas chromatography-mass spectrometry.

    PubMed

    Schneider, J F; Boparai, A S; Reed, L L

    2001-10-01

    A method of screening air and water samples for the chemical-warfare agent Sarin is developed using solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS). The SPME field kit sampler is ideal for collecting air and water samples in the field and transporting samples safely to the laboratory. The sampler also allows the sample to be introduced into the GC-MS system without further sample preparation. Results of the tests with Sarin using the SPME technique indicate that a sample collection time of 5 min is sufficient to detect 100 ng/L of Sarin in air. For water samples, Sarin is detected at a concentration of 12 microg/mL or higher. This method is ideal for screening samples for quick response situations.

  20. Screening for sarin in air and water by solid-phase microextraction-gas chromatography/mass spectrometry.

    SciTech Connect

    Schneider, J. F.; Boparai, A. S.; Reed, L. L.

    2001-10-01

    A method of screening air and water samples for the chemical-warfare agent Sarin is developed using solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS). The SPME field kit sampler is ideal for collecting air and water samples in the field and transporting samples safely to the laboratory. The sampler also allows the sample to be introduced into the GC-MS system without further sample preparation. Results of the tests with Sarin using the SPME technique indicate that a sample collection time of 5 min is sufficient to detect 100 ng/L of Sarin in air. For water samples, Sarin is detected at a concentration of 12 {mu}g/mL or higher. This method is ideal for screening samples for quick response situations.

  1. Quantitation of Insulin-Like Growth Factor 1 in Serum by Liquid Chromatography High Resolution Accurate-Mass Mass Spectrometry.

    PubMed

    Ketha, Hemamalini; Singh, Ravinder J

    2016-01-01

    Insulin-like growth factor 1 (IGF-1) is a 70 amino acid peptide hormone which acts as the principal mediator of the effects of growth hormone (GH). Due to a wide variability in circulating concentration of GH, IGF-1 quantitation is the first step in the diagnosis of GH excess or deficiency. Majority (>95 %) of IGF-1 circulates as a ternary complex along with its principle binding protein insulin-like growth factor 1 binding protein 3 (IGFBP-3) and acid labile subunit. The assay design approach for IGF-1 quantitation has to include a step to dissociate IGF-1 from its ternary complex. Several commercial assays employ a buffer containing acidified ethanol to achieve this. Despite several modifications, commercially available immunoassays have been shown to have challenges with interference from IGFBP-3. Additionally, inter-method comparison between IGF-1 immunoassays has been shown to be suboptimal. Mass spectrometry has been utilized for quantitation of IGF-1. In this chapter a liquid chromatography high resolution accurate-mass mass spectrometry (LC-HRAMS) based method for IGF-1 quantitation has been described.

  2. Mass

    SciTech Connect

    Quigg, Chris

    2007-12-05

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  3. On the relationship between Arctic ice clouds and polluted air masses over the north slope of Alaska in April 2008

    NASA Astrophysics Data System (ADS)

    Jouan, C.; Pelon, J.; Girard, E.; Ancellet, G.; Blanchet, J. P.; Delanoë, J.

    2013-02-01

    Recently, two Types of Ice Clouds (TICs) properties have been characterized using ISDAC airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (<10 L-1) and larger (>110 μm) ice crystals, a larger ice supersaturation (>15%) and a fewer ice nuclei (IN) concentration (<2 order of magnitude) when compared to TIC-1/2A. It has been hypothesized that emissions of SO2 may reduce the ice nucleating properties of IN through acidification, resulting to a smaller concentration of larger ice crystals and leading to precipitation (e.g. cloud regime TIC-2B) because of the reduced competition for the same available moisture. Here, the origin of air masses forming the ISDAC TIC-1/2A (1 April 2008) and TIC-2B (15 April 2008) is investigated using trajectory tools and satellite data. Results show that the synoptic conditions favor air masses transport from the three potentials SO2 emission areas to Alaska: eastern China and Siberia where anthropogenic and biomass burning emission respectively are produced and the volcanic region from the Kamchatka/Aleutians. Weather conditions allow the accumulation of pollutants from eastern China/Siberia over Alaska, most probably with the contribution of acid volcanic aerosol during the TIC-2B period. OMI observations reveal that SO2 concentrations in air masses forming the TIC-2B were larger than in air masses forming the TIC-1/2A. Airborne measurements show high acidity near the TIC-2B flight where humidity was low. These results strongly support the hypothesis that acidic coating on IN are at the origin of the formation of TIC-2B.

  4. On the relationship between Arctic ice clouds and polluted air masses over the North Slope of Alaska in April 2008

    NASA Astrophysics Data System (ADS)

    Jouan, C.; Pelon, J.; Girard, E.; Ancellet, G.; Blanchet, J. P.; Delanoë, J.

    2014-02-01

    Recently, two types of ice clouds (TICs) properties have been characterized using the Indirect and Semi-Direct Aerosol Campaign (ISDAC) airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (< 10 L-1) and larger (> 110 μm) ice crystals, and a larger ice supersaturation (> 15%) compared to TIC-1/2A. It has been hypothesized that emissions of SO2 may reduce the ice nucleating properties of ice nuclei (IN) through acidification, resulting in a smaller concentration of larger ice crystals and leading to precipitation (e.g., cloud regime TIC-2B). Here, the origin of air masses forming the ISDAC TIC-1/2A (1 April 2008) and TIC-2B (15 April 2008) is investigated using trajectory tools and satellite data. Results show that the synoptic conditions favor air masses transport from three potential SO2 emission sources into Alaska: eastern China and Siberia where anthropogenic and biomass burning emissions, respectively, are produced, and the volcanic region of the Kamchatka/Aleutians. Weather conditions allow the accumulation of pollutants from eastern China and Siberia over Alaska, most probably with the contribution of acidic volcanic aerosol during the TIC-2B period. Observation Monitoring Instrument (OMI) satellite observations reveal that SO2 concentrations in air masses forming the TIC-2B were larger than in air masses forming the TIC-1/2A. Airborne measurements show high acidity near the TIC-2B flight where humidity was low. These results support the hypothesis that acidic coating on IN could be at the origin of the formation of TIC-2B.

  5. Association of body mass index and aerobic physical fitness with cardiovascular risk factors in children☆

    PubMed Central

    Gonçalves, Reginaldo; Szmuchrowski, Leszek Antony; Damasceno, Vinícius Oliveira; de Medeiros, Marcelo Lemos; Couto, Bruno Pena; Lamounier, Joel Alves

    2014-01-01

    Objective: To identify the association between both, body mass index and aerobic fitness, with cardiovascular disease risk factors in children. Methods: Cross-sectional study, carried out in Itaúna-MG, in 2010, with 290 school children ranging from 6 to 10 years-old of both sexes, randomly selected. Children from schools located in the countryside and those with medical restrctions for physical activity were not included. Blood sample was collected after a 12-hour fasting period. Blood pressure, stature and weight were evaluated in accordance with international standards. The following were considered as cardiovascular risk factors: high blood pressure, high total cholesterol, LDL, triglycerides and insulin levels, and low HDL. The statistical analysis included the Spearman's coefficient and the logistic regression, with cardiovascular risk factors as dependent variables. Results: Significant correlations were found, in both sexes, among body mass index and aerobic fitness with most of the cardiovascular risk factors. Children of both sexes with body mass index in the fourth quartile demonstrated increased chances of having high blood insulin and clustering cardiovascular risk factors. Moreover, girls with aerobic fitness in the first quartile also demonstrated increased chances of having high blood insulin and clustering cardiovascular risk factors. Conclusion: The significant associations and the increased chances of having cardiovascular risk factors in children with less aerobic fitness and higher levels of body mass index justify the use of these variables for health monitoring in Pediatrics. PMID:25479851

  6. Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall

    PubMed Central

    Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

    2014-01-01

    Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005–2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination. PMID:24722630

  7. Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall.

    PubMed

    Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

    2014-11-01

    Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005-2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination.

  8. Air pollution and anemia as risk factors for pneumonia in ecuadorian children: a retrospective cohort analysis

    PubMed Central

    2011-01-01

    Background Ambient air pollution and malnutrition, particularly anemia, are risk factors for pneumonia, a leading cause of death in children under five. We simultaneously assessed these risk factors in Quito, Ecuador. Methods In 2005, we studied two socioeconomically similar neighborhoods in Quito: Lucha de los Pobres (LP) and Jaime Roldos (JR). LP had relatively high levels of air pollution (annual median PM2.5 = 20.4 μg/m3; NO2 = 29.5 μg/m3) compared to JR (annual median PM2.5 = 15.3 μg/m3; NO2 = 16.6 μg/m3). We enrolled 408 children from LP (more polluted) and 413 children from JR (less polluted). All subjects were aged 18-42 months. We obtained medical histories of prior physician visits and hospitalizations during the previous year, anthropometric nutrition data, hemoglobin levels, and hemoglobin oxygen saturation via oximetry. Results In anemic children, higher pollution exposure was significantly associated with pneumonia hospitalization (OR = 6.82, 95%CI = 1.45-32.00; P = 0.015). In non-anemic children, no difference in hospitalizations by pollution exposure status was detected (OR = 1.04, NS). Children exposed to higher levels of air pollution had more pneumonia hospitalizations (OR = 3.68, 1.09-12.44; P = 0.036), total respiratory illness (OR = 2.93, 95% CI 1.92-4.47; P < 0.001), stunting (OR = 1.88, 1.36-2.60; P < 0.001) and anemia (OR = 1.45, 1.09-1.93; P = 0.013) compared to children exposed to lower levels of air pollution. Also, children exposed to higher levels of air pollution had significantly lower oxygen saturation (92.2% ± 2.6% vs. 95.8% ± 2.2%; P < 0.0001), consistent with air pollution related dyshemoglobinemia. Conclusions Ambient air pollution is associated with rates of hospitalization for pneumonia and with physician's consultations for acute respiratory infections. Anemia may interact with air pollution to increase pneumonia hospitalizations. If confirmed in larger studies, improving nutrition-related anemia, as well as decreasing

  9. Constraining aerosol optical models using ground-based, collocated particle size and mass measurements in variable air mass regimes during the 7-SEAS/Dongsha experiment

    NASA Astrophysics Data System (ADS)

    Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Hsu, N. Christina; Lin, Neng-Huei; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

    2013-10-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment (λ = 550 nm) for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulfate, nitrate, and elemental carbon. Achieving full optical closure is hampered by limitations in accounting for the role of water vapor in the system, uncertainties in the instruments and the need for further knowledge in the source apportionment of the model's major chemical components. Nonetheless, our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulfate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Consistency between the measured and modeled optical parameters serves as an

  10. Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

    NASA Technical Reports Server (NTRS)

    Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

    2012-01-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote

  11. New air Cherenkov light detectors to study mass composition of cosmic rays with energies above knee region

    NASA Astrophysics Data System (ADS)

    Tsunesada, Yoshiki; Katsuya, Ryoichi; Mitsumori, Yu; Nakayama, Keisuke; Kakimoto, Fumio; Tokuno, Hisao; Tajima, Norio; Miranda, Pedro; Salinas, Juan; Tavera, Wilfredo

    2014-11-01

    We have installed a hybrid detection system for air showers generated by cosmic rays with energies greater than 3 ×1015 eV at Mount Chacaltaya (5200 m above the sea level), in order to study the mass composition of cosmic rays above the knee region. This detection system comprises an air shower array with 49 scintillation counters in an area of 500 m×650 m, and seven new Cherenkov light detectors installed in a radial direction from the center of the air shower array with a separation of 50 m. It is known that the longitudinal development of a particle cascade in the atmosphere strongly depends on the type of the primary nucleus, and an air shower initiated by a heavier nucleus develops faster than that by a lighter primary of the same energy, because of the differences in the interaction cross-section and the energy per nucleon. This can be measured by detecting the Cherenkov radiation emitted from charged particles in air showers at higher altitudes. In this paper we describe the design and performance of our new non-imaging Cherenkov light detectors at Mount Chacaltaya that are operated in conjunction with the air shower array. The arrival directions and energies of air showers are determined by the shower array, and information about the primary masses is obtained from the Cherenkov light data including the time profiles and lateral distributions. The detector consists of photomultiplier tube (PMT), high-speed ADCs, other control modules, and data storage device. The Cherenkov light signals from an air shower are typically 10-100 ns long, and the waveforms are digitized with a sampling frequency of 1 GHz and recorded in situ without long-distance analog signal transfers. All the Cherenkov light detectors record their time-series data by receiving a triggering signal transmitted from the trigger module of the air shower array, which is fired by a coincidence of shower signals in four neighboring scintillation counters. The optical characteristics of the

  12. A piloted simulation investigation of the normal load factor and longitudinal thrust required for air-to-air acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Whalley, Matthew S.

    1993-01-01

    A piloted simulation study was performed by the U.S. Army Aeroflighydynamics Directorate to develop insight into the maneuverability requirements for aggressive helicopter maneuvering tasks such as air-to-air combat. Both a conventional helicopter and a helicopter with auxiliary thrust were examined. The aircraft parameters of interest were the normal and longitudinal load factor envelopes. Of particular interest were the mission performance and handling qualities tradeoffs with the parameters of interest. Two air-to-air acquisition and tracking tasks and a return-to-cover task were performed to assess mission performance. Results indicate that without auxiliary thrust, the ownship normal load factor capability needs to match that of the adversary in order to provide satisfactory handling qualities. Auxiliary thrust provides significant handling qualities advantages and can be substituted to some extent for normal load factor capability. Auxiliary thrust levels as low as 0.2 thrust/weight can provide significant handling qualities advantages.

  13. Linear and cyclic methylsiloxanes in air by concurrent solvent recondensation-large volume injection-gas chromatography-mass spectrometry.

    PubMed

    Companioni-Damas, E Y; Santos, F J; Galceran, M T

    2014-01-01

    In the present work, a simple and fast method for the analysis of linear and cyclic methylsiloxanes in ambient air based on active sampling combined with gas chromatography - mass spectrometry (GC-MS) was developed. The retention efficiency of five sampling sorbents (activated coconut charcoal, Carbopack B, Cromosorb 102, Cromosorb 106 and Isolute ENV+) was evaluated and Isolute ENV+ was found to be the most effective. A volume of 2700 L of air can be sampled without significant losses of the most volatile methylsiloxanes. To improve the sensitivity of the GC-MS method, concurrent solvent recondensation - large volume injection (CSR-LVI), using volumes up to 30 µl of sample extract, is proposed and limits of quantification down to 0.03-0.45 ng m(-3), good linearity (r>0.999) and precision (RSD %<9%) were obtained. The developed method was applied to the analysis of ambient air. Concentrations of linear and cyclic methylsiloxanes in indoor air ranging from 3.9 to 319 ng m(-3) and between 48 and 292668 ng m(-3), were obtained, respectively, while levels from 6 to 22 ng m(-3) for linear and between 2.2 and 439 ng m(-3) for cyclic methylsiloxanes in outdoor air from Barcelona (Spain), were found.

  14. Influences of Vehicle Size and Mass and Selected Driver Factors on Odds of Driver Fatality

    PubMed Central

    Padmanaban, Jeya

    2003-01-01

    Research was undertaken to determine vehicle size parameters influencing driver fatality odds, independent of mass, in two-vehicle collisions. Forty vehicle parameters were evaluated for 1,500 vehicle groupings. Logistic regression analyses show driver factors (belt use, age, drinking) collectively contribute more to fatality odds than vehicle factors, and that mass is the most important vehicular parameter influencing fatality odds for all crash configurations. In car crashes, other vehicle parameters with statistical significance had a second order effect compared to mass. In light truck-to-car crashes, “vehicle type-striking vehicle is light truck” was the most important parameter after mass, followed by vehicle height and bumper height, with second order effect. To understand the importance of “vehicle type” variable, further investigation of vehicle “stiffness” and other passenger car/light truck differentiating parameters is warranted. PMID:12941244

  15. International system of units traceable results of Hg mass concentration at saturation in air from a newly developed measurement procedure.

    PubMed

    Quétel, Christophe R; Zampella, Mariavittoria; Brown, Richard J C; Ent, Hugo; Horvat, Milena; Paredes, Eduardo; Tunc, Murat

    2014-08-05

    Data most commonly used at present to calibrate measurements of mercury vapor concentrations in air come from a relationship known as the "Dumarey equation". It uses a fitting relationship to experimental results obtained nearly 30 years ago. The way these results relate to the international system of units (SI) is not known. This has caused difficulties for the specification and enforcement of limit values for mercury concentrations in air and in emissions to air as part of national or international legislation. Furthermore, there is a significant discrepancy (around 7% at room temperature) between the Dumarey data and data calculated from results of mercury vapor pressure measurements in the presence of only liquid mercury. As an attempt to solve some of these problems, a new measurement procedure is described for SI traceable results of gaseous Hg concentrations at saturation in milliliter samples of air. The aim was to propose a scheme as immune as possible to analytical biases. It was based on isotope dilution (ID) in the liquid phase with the (202)Hg enriched certified reference material ERM-AE640 and measurements of the mercury isotope ratios in ID blends, subsequent to a cold vapor generation step, by inductively coupled plasma mass spectrometry. The process developed involved a combination of interconnected valves and syringes operated by computer controlled pumps and ensured continuity under closed circuit conditions from the air sampling stage onward. Quantitative trapping of the gaseous mercury in the liquid phase was achieved with 11.5 μM KMnO4 in 2% HNO3. Mass concentrations at saturation found from five measurements under room temperature conditions were significantly higher (5.8% on average) than data calculated from the Dumarey equation, but in agreement (-1.2% lower on average) with data based on mercury vapor pressure measurement results. Relative expanded combined uncertainties were estimated following a model based approach. They ranged from 2

  16. Respiratory syncytial virus infection in infants and correlation with meteorological factors and air pollutants

    PubMed Central

    2013-01-01

    Background Respiratory Syncytial Virus (RSV) is the most important cause of severe respiratory infections in infants with seasonal epidemics. Environmental factors (temperature, humidity, air pollution) could influence RSV epidemics through their effects on virus activity and diffusion. Methods We conducted a retrospective study on a paediatric population who referred to our Paediatric Emergency Unit in order to analyze the correlation between weekly incidence of RSV positive cases during winter season in Bologna and meteorological factors and air pollutants concentration. Results We observed a significant correlation between the incidence of RSV infections and the mean minimum temperature registered during the same week and the previous weeks. The weekly number of RSV positive cases was also correlated to the mean PM10 concentration of the week before. Conclusions RSV epidemic trend in Bologna (Italy) is related to the mean minimum temperature, and the mean PM10 concentration. PMID:23311474

  17. Using full-mission simulation for human factors research in air transport operations

    NASA Technical Reports Server (NTRS)

    Orlady, Harry W.; Hennessy, Robert W.; Obermayer, Richard; Vreuls, Donald; Murphy, Miles R.

    1988-01-01

    This study examined state-of-the-art mission oriented simulation and its use in human factors research. Guidelines were developed for doing full-mission human factors research on crew member behavior during simulated air transport operations. The existing literature was reviewed. However, interviews with experienced investigators provided the most useful information. The fundamental scientific and practical issues of behavioral research in a simulation environment are discussed. Guidelines are presented for planning, scenario development, and the execution of behavioral research using full-mission simulation in the context of air transport flight operations . Research is recommended to enhance the validity and productivity of full-mission research by: (1) validating the need for high-fidelity simulation of all major elements in the operational environment, (2) improving methods for conducting full-mission research, and (3) examining part-task research on specific problems through the use of vehicles which contain higher levels of abstraction (and lower fidelity) of the operational environment.

  18. A Comparison of the Red Green Blue (RGB) Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles and NOAA G-IV Dropsondes

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Folmer, Michael; Dunion, Jason

    2014-01-01

    RGB air mass imagery is derived from multiple channels or paired channel differences. The combination of channels and channel differences means the resulting imagery does not represent a quantity or physical parameter such as brightness temperature in conventional single channel imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles and NOAA G-IV dropsondes provide insight about the vertical structure of the air mass represented on the RGB air mass imagery and are a first step to validating the imagery.

  19. An Investigation of Reproductive Health Outcomes and Potential Risk Factors in Air Force Women

    DTIC Science & Technology

    1999-10-01

    descriptions of natality and adverse reproductive outcome rates from 1975-1994; (2) projected rates stratified by AF Command and geographic region; and (3) two case - control studies examining the etiology of adverse outcomes.... control studies evaluate ADAF women from 1990-1998. Causal hypotheses evaluate possible effects of occupational exposures and operational factors on...are needed. The results provide a framework within which to interpret the reproductive consequences of future Air Force deployments. Phase II case

  20. Indoor air quality in a middle school, Part II: Development of emission factors for particulate matter and bioaerosols.

    PubMed

    Scheff, P A; Paulius, V K; Curtis, L; Conroy, L M

    2000-11-01

    A middle school (grades 6 to 8) in a residential section of Springfield, Illinois, with no known air quality problems, was selected for a baseline indoor air quality survey. The study was designed to measure and evaluate air quality at the middle school with the objective of providing a benchmark for comparisons with measurements in schools with potential air quality problems. The focus of this article is on the development of emission factors for particulate matter and bioaerosols. The school was characterized as having no health complaints and good maintenance schedules. Four indoor locations including the cafeteria, a science classroom, an art classroom, the lobby outside the main office, and one outdoor location were sampled for various environmental comfort and pollutant parameters for one week in February 1997. Integrated samples (eight-hour sampling time) for respirable and total particulate matter, and short-term measurements (two-minute samples, three times per day) for bioaerosols were collected on three consecutive days at each of the sampling sites. Continuous measurements of carbon dioxide were logged at all locations for five days. Continuous measurements of respirable particulate matter were also collected in the lobby area. A linear relationship between occupancy and corresponding carbon dioxide and particle concentrations was seen. A completely mixed space, one compartment mass balance model with estimated CO2 generation rates and actual CO2 and particulate matter concentrations was used to model ventilation and pollutant emission rates. Emission factors for occupancy were represented by the slope of emission rate versus occupancy scatter plots. The following particle and bioaerosol emission factors were derived from the indoor measurements: total particles: 1.28 mg/hr/person-hr; respirable particles: 0.154 g/hr/person-hr; total fungi: 167 CFU/hr/person-min; thermophilic fungi: 35.8 CFU/hr/person-min; mesophilic fungi: 119 CFU/hr/person-min; total

  1. Surface analysis using a new plasma assisted desorption/ionisation source for mass spectrometry in ambient air

    NASA Astrophysics Data System (ADS)

    Bowfield, A.; Barrett, D. A.; Alexander, M. R.; Ortori, C. A.; Rutten, F. M.; Salter, T. L.; Gilmore, I. S.; Bradley, J. W.

    2012-06-01

    The authors report on a modified micro-plasma assisted desorption/ionisation (PADI) device which creates plasma through the breakdown of ambient air rather than utilising an independent noble gas flow. This new micro-PADI device is used as an ion source for ambient mass spectrometry to analyse species released from the surfaces of polytetrafluoroethylene, and generic ibuprofen and paracetamol tablets through remote activation of the surface by the plasma. The mass spectra from these surfaces compare favourably to those produced by a PADI device constructed using an earlier design and confirm that the new ion source is an effective device which can be used to achieve ambient mass spectrometry with improved spatial resolution.

  2. Air leakage on the postoperative day: powerful factor of postoperative recurrence after thoracoscopic bullectomy

    PubMed Central

    Jeon, Hyun Woo; Kye, Yeo Kon; Kim, Kyung Soo

    2016-01-01

    Background Primary spontaneous pneumothorax (PSP) is a relatively common disorder in young patients. Although various surgical techniques have been introduced, recurrence after video-assisted thoracoscopic surgery (VATS) remains high. The aim of study was to identify the risk factors for postoperative recurrence after thoracoscopic bullectomy in the spontaneous pneumothorax. Methods From January 2011 through March 2013, two hundreds and thirty two patients underwent surgery because of pneumothorax. Patients with a secondary pneumothorax, as well as cases of single port surgery, an open procedure, additional pleural procedure (pleurectomy, pleural abrasion) or lack of medical records were excluded. The records of 147 patients with PSP undergoing 3-port video-assisted thoracoscopic bullectomy with staple line coverage using an absorbable polyglycolic acid (PGA) sheet were retrospectively reviewed. Results The median age was 19 years (range, 11−34 years) with male predominance (87.8%). Median postoperative hospital stay was 3 days (range, 1−10 days) without mortality. Complications were developed in five patients. A total of 24 patients showed postoperative recurrence (16.3%). Younger age less than 17 years old and immediate postoperative air leakage were risk factors for postoperative recurrence after thoracoscopic bullectomy by multivariate analysis. Conclusions Immediate postoperative air leakage was the risk factor for postoperative recurrence. However, further study will be required for the correlation of air leakage with recurrence. PMID:26904217

  3. Quantifying baseline emission factors of air pollutants in China's regional power grids.

    PubMed

    Cai, Wenjia; Wang, Can; Jin, Zhugang; Chen, Jining

    2013-04-16

    Drawing lessons from the clean development mechanism (CDM), this paper developed a combined margin methodology to quantify baseline emission factors of air pollutants in China's regional power grids. The simple average of baseline emission factors of SO2, NOX, and PM2.5 in China's six power grids in 2010 were respectively 1.91 kg/MWh, 1.83 kg/MWh and 0.32 kg/MWh. Several low-efficient mitigation technologies, such as low nitrogen oxide burner (LNB), were suggested to be replaced or used together with other technologies in order to virtually decrease the grid's emission factor. The synergies between GHG and air pollution mitigation in China's power sector was also notable. It is estimated that in 2010, that every 1% CO2 reduction in China's power generation sector resulted in the respective coreduction of 1.1%, 0.5%, and 0.8% of SO2, NOX, and PM2.5. Wind is the best technology to achieve the largest amount of coabatement in most parts of China. This methodology is recommended to be used in making comprehensive air pollution control strategies and in cobenefits analysis in future CDM approval processes.

  4. Air Superiority at Red Flag: Mass, Technology, and Winning the Next War

    DTIC Science & Technology

    2009-10-01

    improved their estimate. In The Art of Wargaming, Peter Perla suggests that adding exercise analysis could help. He recommends a “continuous cycle...Survey, 44. 45. Ibid., 27–28. 46. “Desert Shield Tactical Air Force Combat Losses, Damage, and Muni- tions Consumption.” 47. Ibid. 48. Perla , Art of...Williamson. Strategy for Defeat: The Luftwaffe, 1933– 1945, 1983. Reprint. Maxwell AFB, AL: Air University Press, 2007. Perla , Peter P. The Art of Wargaming

  5. Effective Mass and g Factor of Four-Flux-Quanta Composite Fermions

    SciTech Connect

    Yeh, A.S.; Tsui, D.C.; Stormer, H.L.; Pfeiffer, L.N.; Baldwin, K.W.; West, K.W.; Stormer, H.L.; Tsui, D.C.

    1999-01-01

    We investigate the properties of composite fermions with four attached flux quanta through tilted-field experiments near Landau level filling factor {nu}=3/4 . The observed collapse of fractional quantum Hall gaps in the vicinity of this quarter-filling state can be comprehensively understood in terms of composite fermions with mass and spin. Remarkably, the effective mass and g factor of these four-flux-quanta composite fermions around {nu}=3/4 are very similar to those of two-flux-quanta composite fermions around {nu}=3/2 . {copyright} {ital 1999} {ital The American Physical Society }

  6. Factors on green service industry: Case study at AirAsia

    NASA Astrophysics Data System (ADS)

    Abdullah, Muhammad-Azfar; Chew, Boon-Cheong; Hamid, Syaiful-Rizal

    2017-03-01

    Presently service organizations are challenged by fierce global competition, new technology and changing customer demands. These trends force service sectors to adapt environmental factors and places innovation at the core of their competitive strategy. On the other hand, service sectors challenge to deliver value memorable experiences and complete "service solutions" while lowering costs and keep sustainable. Despite, many studies have attempted to explore the factors that help toward environmental sustainability in the manufacturing sector, the service sector has not yet received a considerable attention in all world countries generally and in developing countries particularly. Thus, this paper aims to explore the factors that help to attain environmental sustainability in the service sector. A qualitative case study through semi-structured interview conducted with twenty managers from AirAsia to explore the factors that are related to environmental sustainability and green services. Besides, secondary data from document analysis was reviewed to gain more comprehensive understanding and triangulate the interview data. The finding of this paper emphasizes to three important factors namely institutional factors, process factors and result factors that each factor contain sustainability and innovations to promote competitive green service in the marketplace.

  7. Evaluating near highway air pollutant levels and estimating emission factors: Case study of Tehran, Iran.

    PubMed

    Nayeb Yazdi, Mohammad; Delavarrafiee, Maryam; Arhami, Mohammad

    2015-12-15

    A field sampling campaign was implemented to evaluate the variation in air pollutants levels near a highway in Tehran, Iran (Hemmat highway). The field measurements were used to estimate road link-based emission factors for average vehicle fleet. These factors were compared with results of an in tunnel measurement campaign (in Resalat tunnel). Roadside and in-tunnel measurements of carbon monoxide (CO) and size-fractionated particulate matter (PM) were conducted during the field campaign. The concentration gradient diagrams showed exponential decay, which represented a substantial decay, more than 50-80%, in air pollutants level in a distance between 100 and 150meters (m) of the highway. The changes in particle size distribution by distancing from highway were also captured and evaluated. The results showed particle size distribution shifted to larger size particles by distancing from highway. The empirical emission factors were obtained by using the roadside and in tunnel measurements with a hypothetical box model, floating machine model, CALINE4, CT-EMFAC or COPERT. Average CO emission factors were estimated to be in a range of 4 to 12g/km, and those of PM10 were 0.1 to 0.2g/km, depending on traffic conditions. Variations of these emission factors under real working condition with speeds were determined.

  8. Physical activity and dark skin tone: protective factors against low bone mass in Mexican men.

    PubMed

    Vivanco-Muñoz, Nalleli; Jo, Talavera; Gerardo, Huitron-Bravo; Juan, Tamayo; Clark, Patricia

    2012-01-01

    A cross-sectional study was conducted on 268 Mexican men between the ages of 13 and 80 yr to evaluate the association of clinical factors related with bone mass. Men from high schools, universities, and retirement homes were invited to participate. Body mass index (BMI) was measured, and bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry for L1-L4 and total hip. Factors related to bone mass were assessed by questionnaire and analyzed using a logistic regression model. Demographic factors (age, education, and occupation), clinical data (BMI, skin tone, previous fracture, history of osteoporosis [OP], and history of fractures), and lifestyle variables (diet, physical activity, sun exposure, and smoking) were evaluated. Physical activity (≥ 60 min/5 times a week) reduced the risk for low BMD for age, osteopenia, and OP at the spine and total hip (odds ratio [OR]: 0.276; 95% confidence interval [CI]: 0.099-0.769; p=0.014; and OR: 0.184; 95% CI: 0.04-0.849; p=0.03, respectively). Dark skin tone was a protective factor, decreasing the risk by up to 70%. In this population of healthy Mexican men (aged 13-80 yr), dark skin and physical activity were protective factors against low bone mass.

  9. EPA Air Method, Toxic Organics - 15 (TO-15): Determination of Volatile Organic Compounds (VOCs) in Air Collected in Specially-Prepared Canisters and Analyzed by Gas Chromatography/Mass Spectrometry (GC/MS)

    EPA Pesticide Factsheets

    Method T)-15 describes procedures for for preparation and analysis of air samples containing volatile organic compounds collected in specially-prepared canisters, using gas chromatography-mass spectrometry.

  10. Air mass origin and its influence on radionuclide activities ( 7Be and 210Pb) in aerosol particles at a coastal site in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Dueñas, C.; Orza, J. A. G.; Cabello, M.; Fernández, M. C.; Cañete, S.; Pérez, M.; Gordo, E.

    2011-07-01

    Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of 7Be and 210Pb in aerosols at Málaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2000-2006 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory clusters. The average concentration values of 7Be and 210Pb over the 7 year period have been found to be 4.6 and 0.58 mBq m -3, respectively, with mean aerosol mass concentration of 53.6 μg m -3. The identified air flow types arriving at Málaga reflect the transitional location of the Iberian Peninsula and show significant differences in radionuclide activities. Air concentrations of both nuclides and the aerosol mass concentration are controlled predominantly by the synoptic scenarios leading to the entrance of dust-laden continental flows from northern Africa and the arrival of polar maritime air masses, as implied by the strong correlations found between the monthly frequencies of the different air masses and the specific activities of both radionuclides. Correlations between activity concentrations and precipitation are significant though lower than with air masses.

  11. Influence of trans-boundary biomass burning impacted air masses on submicron particle number concentrations and size distributions

    NASA Astrophysics Data System (ADS)

    Betha, Raghu; Zhang, Zhe; Balasubramanian, Rajasekhar

    2014-08-01

    Submicron particle number concentration (PNC) and particle size distribution (PSD) in the size range of 5.6-560 nm were investigated in Singapore from 27 June 2009 through 6 September 2009. Slightly hazy conditions lasted in Singapore from 6 to 10 August. Backward air trajectories indicated that the haze was due to the transport of biomass burning impacted air masses originating from wild forest and peat fires in Sumatra, Indonesia. Three distinct peaks in the morning (08:00-10:00), afternoon (13:00-15:00) and evening (16:00-20:00) were observed on a typical normal day. However, during the haze period no distinct morning and afternoon peaks were observed and the PNC (39,775 ± 3741 cm-3) increased by 1.5 times when compared to that during non-haze periods (26,462 ± 6017). The morning and afternoon peaks on the normal day were associated with the local rush hour traffic while the afternoon peak was induced by new particle formation (NPF). Diurnal profiles of PNCs and PSDs showed that primary particle peak diameters were large during the haze (60 nm) period when compared to that during the non-haze period (45.3 nm). NPF events observed in the afternoon period on normal days were suppressed during the haze periods due to heavy particle loading in atmosphere caused by biomass burning impacted air masses.

  12. Thermal desorption-gas chromatography-mass spectrometry method to determine phthalate and organophosphate esters from air samples.

    PubMed

    Aragón, M; Borrull, F; Marcé, R M

    2013-08-16

    A method based on thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) has been developed to determine four organophosphate esters, seven phthalate esters, and bis(2-ethylhexyl) adipate in the gas phase from harbour and urban air samples. The method involves the sampling of 1.5L of air in a Tenax TA sorbent tube followed by thermal desorption (using a Tenax TA cryogenic trap) coupled to gas chromatography-mass spectrometry. The repeatability of the method expressed as %RSD (n=3) is less than 15% and the MQLs are between 0.007μgm(-3) (DMP, TBP, BBP, TPP and DnOP) and 6.7μgm(-3) (DEHP). The method was successfully applied in two areas (urban and harbour) testing two and three points in each one, respectively. Some of these compounds were found in both urban and harbour samples. Di-(2-ethylhexyl)phthalate was the most abundant compound found in both areas at concentration levels between 6.7μgm(-3) and 136.4μgm(-3). This study demonstrates that thermal desorption is an efficient method for the determination of these semi-volatile compounds in the gas phase fraction of air samples.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  14. Air Pollution, Neighbourhood Socioeconomic Factors and Neural Tube Defects in the San Joaquin Valley of California

    PubMed Central

    Padula, Amy M.; Yang, Wei; Carmichael, Suzan L.; Tager, Ira B.; Lurmann, Frederick; Hammond, S. Katharine; Shaw, Gary M.

    2015-01-01

    Background Environmental pollutants and neighbourhood socioeconomic factors have been associated with neural tube defects, but the potential impact of interaction between ambient air pollution and neighbourhood socioeconomic factors on the risks of neural tube defects is not well understood. Methods We used data from the California Center of the National Birth Defects Study and the Children’s Health and Air Pollution Study to investigate whether associations between air pollutant exposure in early gestation and neural tube defects were modified by neighbourhood socioeconomic factors in the San Joaquin Valley of California, 1997–2006. Five pollutant exposures, three outcomes and 9 neighbourhood socioeconomic factors were included for a total of 135 investigated associations. Estimates were adjusted for maternal race-ethnicity, education and multivitamin use. Results We present below odds ratios that exclude 1 and a chi-square test of homogeneity p-value of <0.05. We observed increased odds of spina bifida comparing the highest to lowest quartile of particulate matter <10 micrometres (PM10) among those living in a neighbourhood with: a) median household income of less than $30,000 per year (OR 5.1, 95% CI 1.7, 15.3); b) more than 20% living below the federal poverty level (OR 2.6, 95% CI 1.1, 6.0); and c) more than 30% with less than or equal to a high school education (OR 3.2, 95% CI 1.4, 7.4). The ORs were not statistically significant among those higher SES neighbourhoods. Conclusions Our results demonstrate effect modification by neighbourhood socioeconomic factors in the association of particulate matter and neural tube defects in California. PMID:26443985

  15. Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

    PubMed

    Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

    2015-12-01

    Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

  16. Numerical study of coupled transfer of heat and mass between air and water inside a geothermal water cooling tower

    NASA Astrophysics Data System (ADS)

    Bassem, Mohamed Mehdi; Bourouni, Karim; Thameur Chaibi, Mohamed

    2006-11-01

    In the south of Tunisia, geothermal water is used to irrigate cultures. Since its temperature is very high (70 C), geothermal water is cooled by cooling towers. These towers are sized empirically and present many operating problems such as excessive energy consumption, big loss of vapour and low cooling efficiency. The aim of our work is modelling the coupled heat and mass transfer between air and water inside the cooling tower. The most important results obtained are that the evaporative potential is dominating the convective one in the cooling process. That's why the cooling is more efficient in summer than in hibernal period when humidity of ambient air reaches high values. In other hand, the negative convective phenomenon is illustrated. In fact, at the bottom of the tower, water temperature reaches the air one; the two fluids begin to cooling simultaneously. Air is cooled by convection and water by evaporation. We demonstrate also that there is no point in putting fans in working during cold weather. We studied also the effect of the variation of heat transfer coefficient on the efficiency of cooling.

  17. Modulus Ratio and Joint Factor Concepts to Predict Rock Mass Response

    NASA Astrophysics Data System (ADS)

    Ramamurthy, T.; Latha, G. Madhavi; Sitharam, T. G.

    2017-02-01

    The commonly adopted rock mass classifications, namely RMR, Q and GSI, are used to estimate compressive strength and modulus of rock masses. These values have been examined as per modulus ratio concept, M rj , for their reliability. The design parameters adopted in some of the recent case studies based on these classifications indicate that the M rj values for rock masses are higher than those of the corresponding intact rocks. The joint factor, J f, which is defined as a weakness coefficient in rock mass suggests that modulus ratio of rock mass ( M rj ) has to be less than the modulus ratio of the corresponding intact rock ( M ri ), on the basis of extensive experimental evidence. With joint factor, compressive strength, elastic modulus, cohesion and friction angle were estimated and applied in the analyses of a few cases. The predictions of deformations with this approach agreed well with the field measurements by adapting equivalent continuum approach. The modulus ratio concept is considered to present a unified classification for intact rocks and rock masses. Soil-rock boundary, standup time in under ground excavations and also penetration rate of TBM estimates have been linked to M rj .

  18. Petroleum mass removal from low permeability sediment using air sparging/soil vapor extraction: impact of continuous or pulsed operation

    NASA Astrophysics Data System (ADS)

    Kirtland, Brian C.; Aelion, C. Marjorie

    2000-02-01

    Air sparging and soil vapor extraction (AS/SVE) are innovative remediation techniques that utilize volatilization and microbial degradation to remediate petroleum spills from soils and groundwater. This in situ study investigated the use of AS/SVE to remediate a gasoline spill from a leaking underground storage tank (UST) in the low permeability, clayey soil of the Appalachian Piedmont. The objectives of this study were to evaluate AS/SVE in low permeability soils by quantifying petroleum mass removal rates, monitoring vadose zone contaminant levels, and comparing the mass extraction rates of continuous AS/SVE to 8 and 24 h pulsed operation. The objectives were met by collecting AS/SVE exhaust gas samples and vadose zone air from multi-depth soil vapor probes. Samples were analyzed for O 2, CO 2, BTEX (benzene, toluene, ethylbenzene, xylene), and total combustible hydrocarbon (TCH) concentrations using portable hand meters and gas chromatography. Continuous AS/SVE was effective in removing 608 kg of petroleum hydrocarbons from low permeability soil in 44 days (14.3 kg day -1). Mass removal rates ranged from 2.6 times higher to 5.1 times lower than other AS/SVE studies performed in sandy sediments. BTEX levels in the vadose zone were reduced from about 5 ppm to 1 ppm. Ten pulsed AS/SVE tests removed 78 kg in 23 days and the mean mass removal rate (17.6 kg day -1) was significantly higher than the last 15 days of continuous extraction. Pulsed operation may be preferable to continuous operation because of increased mass removal and decreased energy consumption.

  19. [Spatiotemporal distribution of negative air ion concentration in urban area and related affecting factors: a review].

    PubMed

    Huang, Xiang-Hua; Wang, Jian; Zeng, Hong-Da; Chen, Guang-Shui; Zhong, Xian-Fang

    2013-06-01

    Negative air ion (NAI) concentration is an important indicator comprehensively reflecting air quality, and has significance to human beings living environment. This paper summarized the spatiotemporal distribution features of urban NAI concentration, and discussed the causes of these features based on the characteristics of the environmental factors in urban area and their effects on the physical and chemical processes of NAI. The temporal distribution of NAI concentration is mainly controlled by the periodic variation of solar radiation, while the spatial distribution of NAI concentration along the urban-rural gradient is mainly affected by the urban aerosol distribution, underlying surface characters, and urban heat island effect. The high NAI concentration in urban green area is related to the vegetation life activities and soil radiation, while the higher NAI concentration near the water environment is attributed to the water molecules that participate in the generation of NAI through a variety of ways. The other environmental factors can also affect the generation, life span, component, translocation, and distribution of NAI to some extent. To increase the urban green space and atmospheric humidity and to maintain the soil natural attributes of underlying surface could be the effective ways to increase the urban NAI concentration and improve the urban air quality.

  20. Ambient air analyses using nonspecific flame ionization and electron capture detection compared to specific detection by mass spectroscopy

    SciTech Connect

    Pleil, J.D.; Oliver, K.D.; McClenny, W.A.

    1988-08-01

    Ambient air samples from various studies were analyzed for a specific set of trace-level volatile organic compounds by using a gas chromatograph (GC) equipped with a flame ionization detector (FID) in parallel with an electron capture detector (ECD). The samples were then reanalyzed on a second GC system equipped with a mass selective detector (MSD). GC-FID/ECD data were compared to the nominally correct GC-MSD data to determine the accuracy of the nonspecific detectors, which often do not differentiate the targeted compound from interfering compounds. Qualitative accuracy (capability for correctly identifying compounds on the basis of retention time only) and quantitative accuracy (capability for correctly measuring the concentration of an identified compound on the basis of peak area) were evaluated. Data are presented on a per-compound basis to provide the combined typical results from air samples collected in three geographic regions: Kanawha Valley, WV; Los Angeles, CA, area; and Houston, TX.

  1. Modeling 3D conjugate heat and mass transfer for turbulent air drying of Chilean papaya in a direct contact dryer

    NASA Astrophysics Data System (ADS)

    Lemus-Mondaca, Roberto A.; Vega-Gálvez, Antonio; Zambra, Carlos E.; Moraga, Nelson O.

    2017-01-01

    A 3D model considering heat and mass transfer for food dehydration inside a direct contact dryer is studied. The k- ɛ model is used to describe turbulent air flow. The samples thermophysical properties as density, specific heat, and thermal conductivity are assumed to vary non-linearly with temperature. FVM, SIMPLE algorithm based on a FORTRAN code are used. Results unsteady velocity, temperature, moisture, kinetic energy and dissipation rate for the air flow are presented, whilst temperature and moisture values for the food also are presented. The validation procedure includes a comparison with experimental and numerical temperature and moisture content results obtained from experimental data, reaching a deviation 7-10 %. In addition, this turbulent k- ɛ model provided a better understanding of the transport phenomenon inside the dryer and sample.

  2. Parent/Student Risk and Protective Factors in Understanding Early Adolescent's Body Mass Index

    ERIC Educational Resources Information Center

    Fitzpatrick, Kevin M.; Willis, Don

    2016-01-01

    This article's aim is to examine correlates of middle school students' body mass index (BMI). Little research simultaneously has considered both child and parent correlates in predicting child's BMI; we examine the interrelationships between middle school students and their parent's risks and protective factors and their impact on the child's BMI.…

  3. [Body mass of pregnant females, as a risk factor for the development of obstetric complications].

    PubMed

    Shelia, G P; Beshkenadze, M G

    2012-10-01

    To elucidate the specific courses of the course of pregnancy and labor in patients with obesity and inadequate body mass. 280 women (pregnant females aged 17-38) clinically followed up for pregnancy and labor. The nutritional status was estimated by the Quetle index (QI). Complications of pregnancy were more common in females with insufficient and excessive body mass. There are gestational diabetes, gestoses,uterine inertia,fetal macrosomy and perinatal mortality was observed in 67 % of the obese women , total number of spontaneous abortions was 9 % cases, in females with inadequete body mass. The neonatal outcomes of pregnancy and complications of labor were better in the pregnant females, who had normal QI. Thus, insufficient and/or excersive body mass is premorbid negative background and risk factor for the development of obstetric complications. Further studies will allow us to get answers to some of the issues raised and to the management of pregnant women with obesity and low levels of IQ.

  4. Identifying tropospheric baseline air masses at Mauna Loa Observatory between 2004 and 2010 using Radon-222 and back trajectories

    NASA Astrophysics Data System (ADS)

    Chambers, Scott D.; Zahorowski, Wlodek; Williams, Alastair G.; Crawford, Jagoda; Griffiths, Alan D.

    2013-01-01

    We use 7 years of hourly radon observations at Mauna Loa Observatory (MLO), together with 10-day back trajectories, to identify baseline air masses at the station. The amplitude of the annual MLO radon cycle, based on monthly means, was 98 mBq m-3 (39 -137 mBq m-3), with maximum values in February (90th percentile 330 mBq m-3) and minimum values in August (10th percentile 8.1 mBq m-3). The composite diurnal radon cycle (amplitude 49 mBq m-3) is discussed with reference to the influences of local flow features affecting the site, and a 3-hour diurnal sampling window (0730-1030 HST) is proposed for observing the least terrestrially influenced tropospheric air masses. A set of 763 baseline events is selected, using the proposed sampling window together with trajectory information, and presented along with measured radon concentrations as a supplement. This data set represents a resource for the selection of baseline events at MLO for use with a range of trace species. A reduced set of 196 "deep baseline" events occurring in the July-September window is also presented and discussed. The distribution (10th/50th/90th percentile) of radon in deep-baseline events (8.7/29.2/66.1 mBq m-3) was considerably lower than that for the overall set of 763 baseline events (12.3/40.8/104.1 mBq m-3). Results from a simple budget calculation, using sonde-derived mixing depths and literature-based estimates of oceanic radon flux and radon concentrations in the marine boundary layer, indicate that the main source of residual radon in the lower troposphere under baseline conditions at MLO is downward mixing from aged terrestrial air masses in the upper troposphere.

  5. Continental Land Mass Air Traffic Control (COLM ATC). [using three artificial satellite configurations

    NASA Technical Reports Server (NTRS)

    Pecar, J. A.; Henrich, J. E.

    1973-01-01

    The application of various satellite systems and techniques relative to providing air traffic control services for the continental United States was studied. Three satellite configurations were reviewed. The characteristics and capabilities of the satellites are described. The study includes consideration for the various ranging waveforms, multiple access alternatives, and the power and bandwidth required as a function of the number of users.

  6. Exposures to road traffic, noise, and air pollution as risk factors for type 2 diabetes: A feasibility study in Bulgaria

    PubMed Central

    Dzhambov, Angel M; Dimitrova, Donka D

    2016-01-01

    Type 2 diabetes mellitus (T2DM) is a growing public health problem in Bulgaria. While individual and lifestyle determinants have been researched; till date there has been no study on environmental risks such as road traffic, noise, and air pollution. As a first step toward designing a large-scale population-based survey, we aimed at exploring the overall associations of prevalent T2DM with exposures to road traffic, noise, and air pollution. A total of 513 residents of Plovdiv city, Bulgaria were recruited. Individual data on self-reported doctor-diagnosed T2DM and confounding factors were linked to objective and self-rated exposure indicators. Logistic and log-link Poisson regressions were conducted. In the fully adjusted logistic models, T2DM was positively associated with exposures to Lden 71-80 dB (odds ratio (OR) = 4.49, 95% confidence interval (CI): 1.38, 14.68), fine particulate matter (PM)2.5 25.0-66.8 μg/m3 (OR = 1.32, 95% CI: 0.28, 6.24), benzo alpha pyrene 6.0-14.02 ng/m3 (OR = 1.76, 95% CI: 0.52, 5.98) and high road traffic (OR = 1.40, 95% CI: 0.48, 4.07). Lden remained a significant risk factor in the: Poisson regression model. Other covariates with consistently high multivariate effects were age, gender, body mass index, family history of T2DM, subjective sleep disturbance, and especially bedroom location. We concluded that residential noise exposure might be associated with elevated risk of prevalent T2DM. The inferences made by this research and the lessons learned from its limitations could guide the designing of a longitudinal epidemiological survey in Bulgaria. PMID:27157686

  7. Exposures to road traffic, noise, and air pollution as risk factors for type 2 diabetes: A feasibility study in Bulgaria.

    PubMed

    Dzhambov, Angel M; Dimitrova, Donka D

    2016-01-01

    Type 2 diabetes mellitus (T2DM) is a growing public health problem in Bulgaria. While individual and lifestyle determinants have been researched; till date there has been no study on environmental risks such as road traffic, noise, and air pollution. As a first step toward designing a large-scale population-based survey, we aimed at exploring the overall associations of prevalent T2DM with exposures to road traffic, noise, and air pollution. A total of 513 residents of Plovdiv city, Bulgaria were recruited. Individual data on self-reported doctor-diagnosed T2DM and confounding factors were linked to objective and self-rated exposure indicators. Logistic and log-link Poisson regressions were conducted. In the fully adjusted logistic models, T2DM was positively associated with exposures to L(den) 71-80 dB (odds ratio (OR) = 4.49, 95% confidence interval (CI): 1.38, 14.68), fine particulate matter (PM) 2.5 25.0-66.8 μg/m 3 (OR = 1.32, 95% CI: 0.28, 6.24), benzo alpha pyrene 6.0-14.02 ng/m 3 (OR = 1.76, 95% CI: 0.52, 5.98) and high road traffic (OR = 1.40, 95% CI: 0.48, 4.07). L(den) remained a significant risk factor in the: Poisson regression model. Other covariates with consistently high multivariate effects were age, gender, body mass index, family history of T2DM, subjective sleep disturbance, and especially bedroom location. We concluded that residential noise exposure might be associated with elevated risk of prevalent T2DM. The inferences made by this research and the lessons learned from its limitations could guide the designing of a longitudinal epidemiological survey in Bulgaria.

  8. Air pollution from gas flaring: new emission factor estimates and detection in a West African aerosol remote-sensing climatology

    NASA Astrophysics Data System (ADS)

    MacKenzie, Rob; Fawole, Olusegun Gabriel; Levine, James; Cai, Xiaoming

    2016-04-01

    Gas flaring, the disposal of gas through stacks in an open-air flame, is a common feature in the processing of crude oil, especially in oil-rich regions of the world. Gas flaring is a prominent source of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAH), CO, CO2, nitrogen oxides (NOx), SO2 (in "sour" gas only), and soot (black carbon), as well as the release of locally significant amounts of heat. The rates of emission of these pollutants from gas flaring depend on a number of factors including, but not limited to, fuel composition and quantity, stack geometry, flame/combustion characteristics, and prevailing meteorological conditions. Here, we derive new estimated emission factors (EFs) for carbon-containing pollutants (excluding PAH). The air pollution dispersion model, ADMS5, is used to simulate the dispersion of the pollutants from flaring stacks in the Niger delta. A seasonal variation of the dispersion pattern of the pollutant within a year is studied in relation to the movements of the West Africa Monsoon (WAM) and other prevailing meteorological factors. Further, we have clustered AERONET aerosol signals using trajectory analysis to identify dominant aerosol sources at the Ilorin site in West Africa (4.34 oE, 8.32 oN). A 10-year trajectory-based analysis was undertaken (2005-2015, excluding 2010). Of particular interest are air masses that have passed through the gas flaring region in the Niger Delta area en-route the AERONET site. 7-day back trajectories were calculated using the UK Universities Global Atmospheric Modelling Programme (UGAMP) trajectory model which is driven by analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF). From the back-trajectory calculations, dominant sources are identified, using literature classifications: desert dust (DD); Biomass burning (BB); and Urban-Industrial (UI). We use a combination of synoptic trajectories and aerosol optical properties to distinguish a fourth source

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

    SciTech Connect

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

    2006-03-16

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

  10. Bedding factors and E values for buried pipe installations backfilled with air-modified CLSM

    SciTech Connect

    McGrath, T.J.; Hoopes, R.J.

    1998-10-01

    The use of controlled low strength material (CLSM) as a pipe bedding and backfill material requires characterization in terms of traditional design parameters such as bedding factors for rigid pipe and modulus of soil reaction, or E, values for flexible pipe. Triaxial compression and one-dimensional consolidation tests were conducted on two mixes of air-modified CLSM to establish parameters for use in finite element analyses of buried pipe installations. Both trial mixes contained 25 to 30% entrained air to provide flowability. The tests were conducted at ages of 16 hours, 7 days and 28 days to evaluate the change in strength and stiffness with time. Results of the tests were analyzed to fit parameters to the Duncan hyperbolic soil model with the Selig bulk modulus model. These parameters were then used in analyses of flexible and rigid pipe installations, backfilled with CLSM, to determine traditional installation design parameters. The finite element analyses indicate that bedding factors for rigid pipe installations range from 1.8, for trench installations backfilled at an age of 16 hours, to 2.5 for trench installations backfilled at an age of 28 days. Bedding factors for embankment installations of rigid pipe range from 2.5 to 4.8 for ages from 16 hours to 28 days, respectively. Values for the modulus of soil reaction (E) for installation of flexible pipe range from 7 MPa to 21 MPa (1,000 psi to 3,000 psi) for ages from 16 hours to 28 days respectively.

  11. Factors affecting storage of compressed air in solution mined salt cavities

    SciTech Connect

    Allen, R.D.; Doherty, T.J.; Thoms, R.L.

    1982-08-01

    Geologic factors affecting a salt deposit's acceptability for compressed air energy storage include diameter, depth, thickness, mineralogy, strength, presence of gas, faulting, seismic susceptibility, caprock quality, and rate of dissolution by ground water. Assessment of a potential site involves analyzing existing information, seismic surveying, exploratory drilling, examining salt and caprock, geophysical logging, measuring in situ stress, and determining hydrologic impact. Geologic exploration at Huntorf, Federal Republic of Germany, is discussed. Criteria are presented for cavern design parameters, which include octahedral shear strength, excess lateral stress, depth to cavern top, lateral salt thickness, vertical salt thickness, span, and height-todiameter ratio. Cavern, borehole and surface monitoring methods are discussed.

  12. Intermedia transfer factors for fifteen toxic pollutants released to air basins in California

    SciTech Connect

    McKone, T.E.; Daniels, J.I.; Chiao, F.F.; Hsieh, D.P.H.

    1993-10-01

    This report provides a summary definition of the intermedia-transfer factors (ITFs). Methods are discussed for estimating these parameters in the absence of measured values, and the estimation errors inherent in these estimation methods are considered. A detailed summary is provided of measured and estimated ITF values for fifteen air contaminants. They include: 1,3 butadiene; cadmium; cellosolve; cellosolve acetate; chloroform; di-2-ethylhexylphthalate; 1,4-dioxame; hexachlorobenzene; inorganic arsenic; inorganic lead; nickel; tetrachloroethylene; toluene; toluene-2,4-diisocyanate; and 1,3-xylene. Recommendations are made regarding the expected value and variance in these values for use in exposure models.

  13. Factors Affecting the Corporate Decision-Making Process of Air Transport Manufacturers

    NASA Technical Reports Server (NTRS)

    Ollila, R. G.; Hill, J. D.; Noton, B. R.; Duffy, M. A.; Epstein, M. M.

    1976-01-01

    Fuel economy is a pivotal question influencing the future sale and utilization of commercial aircraft. The NASA Aircraft Energy Efficiency (ACEE) Program Office has a program intended to accelerate the readiness of advanced technologies for energy efficient aircraft. Because the decision to develop a new airframe or engine is a major financial hazard for manufacturers, it is important to know what factors influence the decision making process. A method is described for identifying and ranking individuals and organizations involved at each stage of commercial air transport development, and the barriers that must be overcome in adopting new technologies.

  14. Facility monitoring of chemical warfare agent simulants in air using an automated, field-deployable, miniature mass spectrometer.

    PubMed

    Smith, Jonell N; Noll, Robert J; Cooks, R Graham

    2011-05-30

    Vapors of four chemical warfare agent (CWA) stimulants, 2-chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field-deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual-tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components.

  15. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    SciTech Connect

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-18

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  16. Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

    NASA Astrophysics Data System (ADS)

    Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

    2006-09-01

    An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22cm diameter and 30cm length, purifies an airflow rate of 5000lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application.

  17. Identification of European Air Masses Using an Interactive Computer Technique for Separating Mixed Normal Distributions.

    DTIC Science & Technology

    1982-01-01

    classifying a maritime surface, he refers to the Pacific, Atlantic, or Gulf of Mexico using the general term "maritime" only when the exact origin is...portions of North Atlantic NPA PA air modified over warm North Atlantic TC Southern U.S. and Northern Mexico TG Gulf of Mexico and Caribbean NTG TG...Bergeron, T., 1928: " Uber Die Dreidimensional Verknupfende Wetteranalyse, Teil I." Geofys. Pub!., Vol. 5, No. 6. Berggren, R., 1953: "On Temperature

  18. Properties of individual aerosol particles and their relation to air mass origins in a south China coastal city

    NASA Astrophysics Data System (ADS)

    Shi, Zongbo; He, Kebin; Xue, Zhigang; Yang, Fumo; Chen, Yanju; Ma, Yongliang; Luo, Jiaojiao

    2009-05-01

    Atmospheric particles in urban and rural areas in Shenzhen city were collected in summer and winter 2004. The particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. The fine particles (<1 μm) were categorized into chain-like, elongated, rounded, and others on the basis of their morphology. Chain-like particles were likely soot aggregates. In summer and winter, chain-like particles accounted for 43% and 42% of total particles in the urban area, and 22% and 43% in the rural area, respectively. The elongated particles were mixtures of aged sea salts and ammonium sulfate, suggesting an aqueous phase reaction mechanism, i.e., in-cloud sulfate formation. Such particles occupied 12% of total particles in the urban area in the summer and were rarely observed in the wintertime samples. The rounded particles were mainly composed of sulfate and/or carbon. Their number concentration in the urban area was more than three times higher in the winter. In addition, we found that air masses from northern inland contained much higher concentrations of particles than those from the ocean. This was particularly evident in the rural area, where concentrations of chain-like and rounded particles were eight times higher in the continental air masses. These results suggest the strong influence of regional pollution on the particle number concentrations in the coastal city.

  19. 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.

  20. An improved, automated whole air sampler and gas chromatography mass spectrometry analysis system for volatile organic compounds in the atmosphere

    NASA Astrophysics Data System (ADS)

    Lerner, Brian M.; Gilman, Jessica B.; Aikin, Kenneth C.; Atlas, Elliot L.; Goldan, Paul D.; Graus, Martin; Hendershot, Roger; Isaacman-VanWertz, Gabriel A.; Koss, Abigail; Kuster, William C.; Lueb, Richard A.; McLaughlin, Richard J.; Peischl, Jeff; Sueper, Donna; Ryerson, Thomas B.; Tokarek, Travis W.; Warneke, Carsten; Yuan, Bin; de Gouw, Joost A.

    2017-01-01

    Volatile organic compounds were quantified during two aircraft-based field campaigns using highly automated, whole air samplers with expedited post-flight analysis via a new custom-built, field-deployable gas chromatography-mass spectrometry instrument. During flight, air samples were pressurized with a stainless steel bellows compressor into electropolished stainless steel canisters. The air samples were analyzed using a novel gas chromatograph system designed specifically for field use which eliminates the need for liquid nitrogen. Instead, a Stirling cooler is used for cryogenic sample pre-concentration at temperatures as low as -165 °C. The analysis system was fully automated on a 20 min cycle to allow for unattended processing of an entire flight of 72 sample canisters within 30 h, thereby reducing typical sample residence times in the canisters to less than 3 days. The new analytical system is capable of quantifying a wide suite of C2 to C10 organic compounds at part-per-trillion sensitivity. This paper describes the sampling and analysis systems, along with the data analysis procedures which include a new peak-fitting software package for rapid chromatographic data reduction. Instrument sensitivities, uncertainties and system artifacts are presented for 35 trace gas species in canister samples. Comparisons of reported mixing ratios from each field campaign with measurements from other instruments are also presented.

  1. The Interaction Effects of Meteorological Factors and Air Pollution on the Development of Acute Coronary Syndrome

    PubMed Central

    Huang, Ching-Hui; Lin, Heng-Cheng; Tsai, Chen-Dao; Huang, Hung-Kai; Lian, Ie-Bin; Chang, Chia-Chu

    2017-01-01

    This study investigated the interaction effects of meteorological factors and air pollutants on the onset of acute coronary syndrome (ACS). Data of ACS patients were obtained from the Taiwan ACS Full Spectrum Registry and comprised 3164 patients with a definite onset date during the period October 2008 and January 2010 at 39 hospitals. Meteorological conditions and air pollutant concentrations at the 39 locations during the 488-day period were obtained. Time-lag Poisson and logistic regression were used to explore their association with ACS incidence. One-day lag atmospheric pressure (AP), humidity, particulate matter (PM2.5, and PM10), and carbon monoxide (CO) all had significant interaction effects with temperature on ACS occurrence. Days on which high temperatures (>26 °C) and low AP (<1009 hPa) occurred the previous day were associated with a greater likelihood of increased incidence of developing ACS. Typhoon Morakot was an example of high temperature with extremely low AP associated with higher ACS incidence than the daily average. Combinations of high concentrations of PM or CO with low temperatures (<21 °C) and high humidity levels with low temperatures were also associated with increased incidence of ACS. Atmospheric pollution and weather factors have synergistic effects on the incidence of ACS. PMID:28276507

  2. The Interaction Effects of Meteorological Factors and Air Pollution on the Development of Acute Coronary Syndrome

    NASA Astrophysics Data System (ADS)

    Huang, Ching-Hui; Lin, Heng-Cheng; Tsai, Chen-Dao; Huang, Hung-Kai; Lian, Ie-Bin; Chang, Chia-Chu

    2017-03-01

    This study investigated the interaction effects of meteorological factors and air pollutants on the onset of acute coronary syndrome (ACS). Data of ACS patients were obtained from the Taiwan ACS Full Spectrum Registry and comprised 3164 patients with a definite onset date during the period October 2008 and January 2010 at 39 hospitals. Meteorological conditions and air pollutant concentrations at the 39 locations during the 488-day period were obtained. Time-lag Poisson and logistic regression were used to explore their association with ACS incidence. One-day lag atmospheric pressure (AP), humidity, particulate matter (PM2.5, and PM10), and carbon monoxide (CO) all had significant interaction effects with temperature on ACS occurrence. Days on which high temperatures (>26 °C) and low AP (<1009 hPa) occurred the previous day were associated with a greater likelihood of increased incidence of developing ACS. Typhoon Morakot was an example of high temperature with extremely low AP associated with higher ACS incidence than the daily average. Combinations of high concentrations of PM or CO with low temperatures (<21 °C) and high humidity levels with low temperatures were also associated with increased incidence of ACS. Atmospheric pollution and weather factors have synergistic effects on the incidence of ACS.

  3. Cardiovascular risk factors and food consumption of cadets from the Brazilian Air Force Academy.

    PubMed

    Hilgenberg, Fernanda Elisabete; Santos, Annelisa Silva E Alves de Carvalho; Silveira, Erika Aparecida; Cominetti, Cristiane

    2016-04-01

    This article aims to investigate the prevalence of cardiovascular risk factors and food intake inadequacies in cadets from the Brazilian Air Force Academy and the association with sex and year of graduation. Cross-sectional study with 166 adult cadets from the Air Force Academy, placed in Pirassununga - SP, from June to December 2013. Anthropometric measures, biochemical and clinical parameters, physical activity level, smoking habit and food intake were evaluated. Pearson's Chi-square and Fisher's exact tests were used. Overweight prevalence (BMI > 25.0 kg/m2) was 29.7% in men and 16.7% in women. Hypertension was observed in 15.2% of men. Hypercholesterolemia was detected in 50.7% of the cadets; 24.3% presented high levels of low-density lipoprotein and 11.2%, low levels of high-density lipoprotein. There was association between the time spent in the Academy and low levels of high-density lipoprotein. High intake of saturated fat (87.2%) and cholesterol (42.7%) were observed. Inadequate intake of fibers was verified in 92.7% of the sample. There was considerable prevalence of cardiovascular risk factors among the cadets, especially hypercholesterolemia and inadequate food intake.

  4. Copper-dependent inflammation and nuclear factor-kappaB activation by particulate air pollution.

    PubMed

    Kennedy, T; Ghio, A J; Reed, W; Samet, J; Zagorski, J; Quay, J; Carter, J; Dailey, L; Hoidal, J R; Devlin, R B

    1998-09-01

    Particulate air pollution causes increased cardiopulmonary morbidity and mortality, but the chemical determinants responsible for its biologic effects are not understood. We studied the effect of total suspended particulates collected in Provo, Utah, an area where an increase in respiratory symptoms in relation to levels of particulate pollution has been well documented. Provo particulates caused cytokine-induced neutrophil chemoattractant-dependent inflammation of rat lungs. Provo particulates stimulated interleukin-6 (IL-6) and IL-8 production, increased IL-8 messenger RNA (mRNA) and enhanced expression of intercellular adhesion molecule-1 (ICAM-1) in cultured BEAS-2B cells, and stimulated IL-8 secretion in primary cultures of human bronchial epithelium. Cytokine secretion was preceded by activation of the transcription factor nuclear factor-kappaB (NF-kappaB) and was reduced by treatment of cultures with superoxide dismutase, deferoxamine, or N-acetylcysteine. These biologic effects were replicated by culturing BEAS cells with quantities of Cu2+ found in Provo extract. IL-8 secretion by BEAS cells could be modified by addition of normal constituents of airway lining fluid to the culture medium. Mucin significantly reduced IL-8 secretion, and ceruloplasmin significantly increased IL-8 secretion and activation of NF-kappaB. These findings suggest that copper ions may cause some of the biologic effects of inhaled particulate air pollution in the Provo region of the United States, and may provide an explanation for the sensitivity of asthmatic individuals to Provo particulates that has been observed in epidemiologic studies.

  5. Identification of oxidation products of solanesol produced during air sampling for tobacco smoke by electrospray mass spectrometry and HPLC.

    PubMed

    Tucker, Samuel P; Pretty, Jack R

    2005-10-01

    Solanesol, a 45-carbon, trisesquiterpenoid alcohol found in tobacco leaves and tobacco smoke, has been used as a quantitative marker for tobacco smoke for years. However, solanesol appears to be unreliable as a quantitative marker for tobacco smoke during environmental air sampling because it can be degraded substantially when present as a component of tobacco smoke and by as much as 100% when present as pure solanesol on fortified filters during air sampling. Since there is strong evidence that ozone is the agent responsible for the degradation, solanesol appears to be unreliable as a quantitative marker during indoor air sampling when indoor levels of ozone are greater than about 15 ppb. The degree of loss of pure solanesol is directly proportional to the concentration of ozone and the length of the sampling period and depends on the type of 37 mm membrane filter used for air sampling (PTFE or quartz fiber). While the degree of loss of solanesol is inversely proportional to the relative humidity of the air at a sampling rate of 1.7 L min(-1), the degree of loss is virtually independent of relative humidity at a lower sampling rate; i.e., 0.25 L min(-1). A curve of loss of solanesol on a filter versus concentration of ozone from an ozone generator is virtually identical to a curve segment based on atmospheric ozone under the same conditions of air sampling. Oxidation of solanesol by ozone to approximately 25 to 60% completion produces at least three series of products for a total of at least 26 compounds: (1) isoprenoid acetones, (2)omega-hydroxyisoprenoid acetaldehydes, and (3) isoprenoid oxoaldehydes. All products in each series were tentatively identified as their derivatives with 2-(p-aminophenyl)ethanol (APE) by electrospray mass spectrometry (ES-MS). Ten ozonation products were detected as their 2,4-dinitrophenylhydrazine derivatives by HPLC at 360 nm: 4-oxopentanal and nine isoprenoid acetones (acetone, 6-methyl-5-hepten-2-one, geranylacetone

  6. Operational Use of the AIRS Total Column Ozone Retrievals Along with the RGB Air Mass Product as Part of the GOES-R Proving Ground

    NASA Technical Reports Server (NTRS)

    Folmer, Michael; Zavodsky, Bradley; Molthan, Andrew

    2012-01-01

    The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) Hydrometeorological Prediction Center (HPC) and Ocean Prediction Center (OPC) provide short-term and medium-range forecast guidance of heavy precipitation, strong winds, and other features often associated with mid-latitude cyclones over both land and ocean. As a result, detection of factors that lead to rapid cyclogenesis and high wind events is key to improving forecast skill. One phenomenon that has been identified with these events is the stratospheric intrusion that occurs near tropopause folds. This allows for deep mixing near the top of the atmosphere where dry air high in ozone concentrations and potential vorticity descends (sometimes rapidly) deep into the mid-troposphere. Observations from satellites can aid in detection of these stratospheric air intrusions (SAI) regions. Specifically, multispectral composite imagery assign a variety of satellite spectral bands to the red, green, and blue (RGB) color components of imagery pixels and result in color combinations that can assist in the detection of dry stratospheric air associated with PV advection, which in turn may alert forecasters to the possibility of a rapidly strengthening storm system. Single channel or RGB satellite imagery lacks quantitative information about atmospheric moisture unless the sampled brightness temperatures or other data are converted to estimates of moisture via a retrieval process. Thus, complementary satellite observations are needed to capture a complete picture of a developing storm system. Here, total column ozone retrievals derived from a hyperspectral sounder are used to confirm the extent and magnitude of SAIs. Total ozone is a good proxy for defining locations and intensity of SAIs and has been used in studies evaluating that phenomenon (e.g. Tian et al. 2007, Knox and Schmidt 2005). Steep gradients in values of total ozone seen by satellites have been linked

  7. Dependence of exhaled breath composition on exogenous factors, smoking habits and exposure to air pollutants*

    PubMed Central

    Mochalski, P; Filipiak, A; Bajtarevic, A; Ager, C; Denz, H; Hilbe, W; Jamnig, H; Hackl, M; Dzien, A; Amann, A

    2013-01-01

    Non-invasive disease monitoring on the basis of volatile breath markers is a very attractive but challenging task. Several hundreds of compounds have been detected in exhaled air using modern analytical techniques (e.g. proton-transfer reaction mass spectrometry, gas chromatography-mass spectrometry) and have even been linked to various diseases. However, the biochemical background for most of compounds detected in breath samples has not been elucidated; therefore, the obtained results should be interpreted with care to avoid false correlations. The major aim of this study was to assess the effects of smoking on the composition of exhaled breath. Additionally, the potential origin of breath volatile organic compounds (VOCs) is discussed focusing on diet, environmental exposure and biological pathways based on other’s studies. Profiles of VOCs detected in exhaled breath and inspired air samples of 115 subjects with addition of urine headspace derived from 50 volunteers are presented. Samples were analyzed with GC-MS after preconcentration on multibed sorption tubes in case of breath samples and solid phase micro-extraction (SPME) in the case of urine samples. Altogether 266 compounds were found in exhaled breath of at least 10% of the volunteers. From these, 162 compounds were identified by spectral library match and retention time (based on reference standards). It is shown that the composition of exhaled breath is considerably influenced by exposure to pollution and indoor-air contaminants and particularly by smoking. More than 80 organic compounds were found to be significantly related to smoking, the largest group comprising unsaturated hydrocarbons (29 dienes, 27 alkenes and 3 alkynes). On the basis of the presented results, we suggest that for the future understanding of breath data it will be necessary to carefully investigate the potential biological origin of volatiles, e.g., by means of analysis of tissues, isolated cell lines or other body fluids. In

  8. Statistical Characteristics of Experimental Geysers: Factors Controlling Mass and Style of Eruption

    NASA Astrophysics Data System (ADS)

    Toramaru, A.; Maeda, K.

    2011-12-01

    to volume of empty at the conduit top. Once the eruption is triggered, mass proportional to number fraction φ D of parcels with temperature higher than decompression boiling point under free of conduit water is erupted. Assuming that the rectangular area from the top to the depth n (φ S}+φ {D) of square flask is erupted, the erupted mass is calculated by n ± n (φ S}+φ {D). The sum of φ S}+φ {D and the enclosed area is defined as explosive mass which contributes to the explosivity of eruption, and the explosivity index (EI) is calculated by the mass ratio of (explosive mass)/(erupted mass). Presuming a specific system, we carried out Monte Carlo simulations with varying average and variance of temperature PDF as parameters to obtain the statistical properties of erupted mass and EI. As a result, we find that a system with higher average temperature and smaller variance produces mostly explosive eruptions with larger mass with Gaussian type of frequency distribution. Thus, from results of laboratory experiments and simulations, we conclude that the spatial heterogeneity of supersaturated state or temperature in chamber is a key factor to control the eruption style and erupted mass.

  9. Upper air relaxation in regional climate model improves resolved interannual variability of the surface mass balance of Antarctica

    NASA Astrophysics Data System (ADS)

    van de Berg, Willem Jan; Medley, Brooke; van Meijgaard, Erik

    2015-04-01

    The surface mass balance (SMB) determines the variability of the mass balance of the Antarctic Ice sheet on sub-decadal timescales. Since continent-wide SMB cannot be measured, it must be modeled and regional climate models (RCMs) generally outperform global reanalyses in the representation of total mass flux and the spatial distribution of SMB. However, if RCMs are only forced with reanalysis on their lateral boundaries, the representation of the interannual variability of SMB deteriorates significantly. In this study we show how to improve the resolved interannual variability in RCM modeled SMB. For this purpose we use annual SMB observations in the Thwaites drainage basin in Antarctica derived from airborne radar reflections and the RCM RACMO2. RACMO2, driven by ERA-Interim, better represents the mean spatial SMB pattern in this basin than ERA-Interim. However, without relaxation in the interior, RACMO2 poorly resolves the observed interannual SMB variability. If we gently relax the temperature and wind field in the upper atmosphere in RACMO2 to ERA-Interim, RACMO2 gets the best of both. Upper air relaxation little changes the mean SMB and spatial pattern compared to the original RACMO2 output, but allows RACMO2 to resolve the observed interannual SMB as good as ERA-Interim.

  10. Assessment of the Losses Due to Self Absorption by Mass Loading on Radioactive Particulate Air Stack Sample Filters

    SciTech Connect

    Smith, Brian M.; Barnett, J. Matthew; Ballinger, Marcel Y.

    2011-01-18

    This report discusses the effect of mass loading of a membrane filter on the self absorption of radioactive particles. A relationship between mass loading and percent loss of activity is presented. Sample filters were collected from Pacific Northwest National Laboratory (PNNL) facilities in order to analyze the current self absorption correction factor of 0.85 that is being used for both alpha and beta particles. Over an eighteen month period from February 2009 to July 2010, 116 samples were collected and analyzed from eight different building stacks in an effort coordinated by the Effluent Management group. Eleven unused filters were also randomly chosen to be analyzed in order to determine background radiation. All of these samples were collected and analyzed in order to evaluate the current correction factor being used.

  11. Decomposing the profile of PM in two low polluted German cities--mapping of air mass residence time, focusing on potential long range transport impacts.

    PubMed

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2014-07-01

    This paper aims to decompose the profile of particulates in Karlsruhe and Potsdam (Germany), focusing on the localization of PM potential transboundary sources. An air mass cluster analysis was implemented, followed by a study of air mass residence time on a grid of a 0.5° × 0.5° resolution. Particulate/gaseous daily air pollution and meteorological data were used to indicate PM local sources. Four Principal Component Analysis (PCA) components were produced: traffic, photochemical, industrial/domestic and particulate. PM2.5/PM10 ratio seasonal trends, indicated production of PMCOARSE (PM10-PM2.5) from secondary sources in Potsdam during warm period (WP). The residing areas of incoming slow moving air masses are potential transboundary PM sources. For Karlsruhe those areas were mainly around the city. An air mass residence time secondary peak was observed over Stuttgart. For Potsdam, areas with increased dwelling time of the arriving air parcels were detected particularly above E/SE Germany.

  12. PAHs pollution from traffic sources in air of Hangzhou, China: trend and influencing factors.

    PubMed

    Zhu, Li-Zhong; Wang, Jing

    2005-01-01

    PAHs pollution in air of arterial roads was investigated from October 1998 to October 2001 in Hangzhou, China. The results showed that sigma10 PAHs was 13-36 microg/m3, among which, BaP, a strong carcinogenic kind ranged from 0.034 microg/m3 to 0.12 microg/m3. PAHs pollutions in four seasons were winter > autumn > spring-summer. The annual averages of sigmaPAHs concentration were 25 microg/m3 for 1999, 28 microg/m3 for 2000, and 29 microg/m3 for 2001, respectively. Leaded gasoline was banned in December 1998 in Hangzhou, thus comparative measurements with PAHs in leaded and lead-free gasoline powered motor exhausts made it certain that the use of lead-free gasoline leaded to a heavier PAHs pollution in roadside air from December, 1998, in China, and sigmaPAHs in air samples after the lead-banning were more than twice of that in samples before the action. For the large contribution of vehicle discharge to air pollution in roadside, further research was performed to suggest the factors influencing PAHs distribution in vehicle exhaust in order to control air pollution effectively. Compared to gasoline engines, emissions from diesel engines were less toxic, although they might produce more PAHs. Of the same vehicular and oil type, automobiles of longer mileages produced more toxic PAHs. PAHs distributions in the vehicular exhausts were related to the oil type. Large difference was found in the abundance of 3-, 5- and 6-ring PAHs between exhausts from gasoline and diesel oil engines. Diesel oil engines produced relative lighter PAHs such as NAPH, ACEN, FLUOR, while gasoline engines emitted heavier kinds such as BkF, IN and BP. The automobile produced more PAHs with the increase of mileage especially FLUR, PY, BaP, BP. Some significant ratios for traffic source in Hangzhou such as PHEN/AN, FLUR/PY, IN/BP were 0.50-4.3, 0.58-7.4, 0.51-1.5, respectively. A source fingerprint for vehicle exhausts of a mixture of vehicle and oil types in the city district for light

  13. Correction factors for the INER-improved free-air ionization chambers calculated with the Monte Carlo method.

    PubMed

    Lin, Uei-Tyng; Chu, Chien-Hau

    2006-05-01

    Monte Carlo method was used to simulate the correction factors for electron loss and scattered photons for two improved cylindrical free-air ionization chambers (FACs) constructed at the Institute of Nuclear Energy Research (INER, Taiwan). The method is based on weighting correction factors for mono-energetic photons with X-ray spectra. The newly obtained correction factors for the medium-energy free-air chamber were compared with the current values, which were based on a least-squares fit to experimental data published in the NBS Handbook 64 [Wyckoff, H.O., Attix, F.H., 1969. Design of free-air ionization chambers. National Bureau Standards Handbook, No. 64. US Government Printing Office, Washington, DC, pp. 1-16; Chen, W.L., Su, S.H., Su, L.L., Hwang, W.S., 1999. Improved free-air ionization chamber for the measurement of X-rays. Metrologia 36, 19-24]. The comparison results showed the agreement between the Monte Carlo method and experimental data is within 0.22%. In addition, mono-energetic correction factors for the low-energy free-air chamber were calculated. Average correction factors were then derived for measured and theoretical X-ray spectra at 30-50 kVp. Although the measured and calculated spectra differ slightly, the resulting differences in the derived correction factors are less than 0.02%.

  14. Air-sea fluxes and satellite-based estimation of water masses formation

    NASA Astrophysics Data System (ADS)

    Sabia, Roberto; Klockmann, Marlene; Fernandez-Prieto, Diego; Donlon, Craig

    2015-04-01

    Recent work linking satellite-based measurements of sea surface salinity (SSS) and sea surface temperature (SST) with traditional physical oceanography has demonstrated the capability of generating routinely satellite-derived surface T-S diagrams [1] and analyze the distribution/dynamics of SSS and its relative surface density with respect to in-situ measurements. Even more recently [2,3], this framework has been extended by exploiting these T-S diagrams as a diagnostic tool to derive water masses formation rates and areas. A water mass describes a water body with physical properties distinct from the surrounding water, formed at the ocean surface under specific conditions which determine its temperature and salinity. The SST and SSS (and thus also density) at the ocean surface are largely determined by fluxes of heat and freshwater. The surface density flux is a function of the latter two and describes the change of the density of seawater at the surface. To obtain observations of water mass formation is of great interest, since they serve as indirect observations of the thermo-haline circulation. The SSS data which has become available through the SMOS [4] and Aquarius [5] satellite missions will provide the possibility of studying also the effect of temporally-varying SSS fields on water mass formation. In the present study, the formation of water masses as a function of SST and SSS is derived from the surface density flux by integrating the latter over a specific area and time period in bins of SST and SSS and then taking the derivative of the total density flux with respect to density. This study presents a test case using SMOS SSS, OSTIA SST, as well as Argo ISAS SST and SSS for comparison, heat fluxes from the NOCS Surface Flux Data Set v2.0, OAFlux evaporation and CMORPH precipitation. The study area, initially referred to the North Atlantic, is extended over two additional ocean basins and the study period covers the 2011-2012 timeframe. Yearly, seasonal

  15. A Comparison of Mass-Based Emission Factors from Laboratory Combustion of Boreal and Sub-Tropical Peat

    NASA Astrophysics Data System (ADS)

    Knue, J.; Yatavelli, R. L. N.; Chen, L. W. A. A.; Samburova, V.; Gyawali, M. S.; Watts, A.; Chakrabarty, R. K.; Moosmuller, H.; Wang, X.; Zielinska, B.; Chow, J. C.; Watson, J. G.; Tsibart, A.

    2014-12-01

    Peatlands cover approximately 3% of the Earth's surface, but account for approximately one-third of terrestrial soil carbon. This carbon is also much older, collected over hundreds to thousands of years, than other commonly encountered wildfire fuels such as Ponderosa Pine (i.e., years to decades). Due to the moisture and mineral content of peat it has a propensity to smolder, unlike Ponderosa Pine which has an intense flaming period when burning. To better understand the emission from peat fires, in comparison to Ponderosa Pine, a series of experiments were performed in the 8 m3 combustion chamber located at the Desert Research Institute in Reno, NV. Peat from Alaska and Florida (USA) and Siberia (Russia) were burned at two moisture content levels (25 & 50%). Ponderosa Pine needles from Sierra Nevada sites were burned at one moisture content level (8.2%). Real-time measurements included gaseous carbon monoxide (CO), carbon dioxide (CO2), oxides of nitrogen (NOx = NO + NO2), and ozone (O3) concentration, as well as particulate matter (PM) mass, size distribution, and black carbon concentration. In addition, Teflon-membrane and quartz-fiber filters as well as Teflon-impregnated glass fiber (TIGF) filters followed by XAD-4 cartridges were collected for detailed PM chemical speciation. Changes in fuel mass and combustion temperature were continuously monitored during each experiment. We will present a comparison of mass-based emission factors of inorganic gases, PM and black carbon mass concentrations, organic and elemental carbon, and a number of intermediate-volatility (300mass concentration, C*<3x106 μg m-3) and semi-volatile (0.3

  16. Factors Affecting Parent’s Perception on Air Quality—From the Individual to the Community Level

    PubMed Central

    Guo, Yulin; Liu, Fengfeng; Lu, Yuanan; Mao, Zongfu; Lu, Hanson; Wu, Yanyan; Chu, Yuanyuan; Yu, Lichen; Liu, Yisi; Ren, Meng; Li, Na; Chen, Xi; Xiang, Hao

    2016-01-01

    The perception of air quality significantly affects the acceptance of the public of the government’s environmental policies. The aim of this research is to explore the relationship between the perception of the air quality of parents and scientific monitoring data and to analyze the factors that affect parents’ perceptions. Scientific data of air quality were obtained from Wuhan’s environmental condition reports. One thousand parents were investigated for their knowledge and perception of air quality. Scientific data show that the air quality of Wuhan follows an improving trend in general, while most participants believed that the air quality of Wuhan has deteriorated, which indicates a significant difference between public perception and reality. On the individual level, respondents with an age of 40 or above (40 or above: OR = 3.252; 95% CI: 1.170–9.040), a higher educational level (college and above: OR = 7.598; 95% CI: 2.244–25.732) or children with poor healthy conditions (poor: OR = 6.864; 95% CI: 2.212–21.302) have much more negative perception of air quality. On the community level, industrial facilities, vehicles and city construction have major effects on parents’ perception of air quality. Our investigation provides baseline information for environmental policy researchers and makers regarding the public’s perception and expectation of air quality and the benefits to the environmental policy completing and enforcing. PMID:27187432

  17. Evaluating heterogeneity in indoor and outdoor air pollution using land-use regression and constrained factor analysis.

    PubMed

    Levy, Jonathan I; Clougherty, Jane E; Baxter, Lisa K; Houseman, E Andres; Paciorek, Christopher J

    2010-12-01

    Previous studies have identified associations between traffic exposures and a variety of adverse health effects, but many of these studies relied on proximity measures rather than measured or modeled concentrations of specific air pollutants, complicating interpretability of the findings. An increasing number of studies have used land-use regression (LUR) or other techniques to model small-scale variability in concentrations of specific air pollutants. However, these studies have generally considered a limited number of pollutants, focused on outdoor concentrations (or indoor concentrations of ambient origin) when indoor concentrations are better proxies for personal exposures, and have not taken full advantage of statistical methods for source apportionment that may have provided insight about the structure of the LUR models and the interpretability of model results. Given these issues, the primary objective of our study was to determine predictors of indoor and outdoor residential concentrations of multiple traffic-related air pollutants within an urban area, based on a combination of central site monitoring data; geographic information system (GIS) covariates reflecting traffic and other outdoor sources; questionnaire data reflecting indoor sources and activities that affect ventilation rates; and factor-analytic methods to better infer source contributions. As part of a prospective birth cohort study assessing asthma etiology in urban Boston, we collected indoor and/or outdoor 3-to-4 day samples of nitrogen dioxide (NO2) and fine particulate matter with an aerodynamic diameter or = 2.5 pm (PM2.5) at 44 residences during multiple seasons of the year from 2003 through 2005. We performed reflectance analysis, x-ray fluorescence spectroscopy (XRF), and high-resolution inductively coupled plasma-mass spectrometry (ICP-MS) on particle filters to estimate the concentrations of elemental carbon (EC), trace elements, and water-soluble metals, respectively. We derived

  18. Effect of ozone and open air factor against aerosolized Micrococcus luteus.

    PubMed

    Bailey, Roger; Fielding, Louise; Young, Andy; Griffith, Chris

    2007-12-01

    Because of increased concerns over failures in cleaning, the role of bioaerosols, and the environmental and clinical persistence of pathogens, the evaluation of novel decontaminants is increasingly important. The bactericidal properties of open air factor (OAF; a collection of highly reactive chemical species) were identified in the 1970s; however, the potential practical applications of artificially generated OAF have been considered only recently. In this study, the effects of OAF against Micrococcus luteus were investigated. OAF was generated and distributed in a bioaerosol test chamber by delivery of monoterpenes into ozonated air (0.1 ppm) at concentrations of 2.0 (high), 0.75 (medium), or 0.3 (low) mgm(-3) h(-1). M. luteus was aerosolized, and the number of culturable survivors was determined after 2, 5, 10, 20, and 60 min. Culturable bacteria were enumerated by aerobic plate counts in all-glass impinger fluid. Data were analyzed for statistical significance using one- or two-way analyses of variance. When aerosolized bacteria were exposed to ozone alone (0.05, 0.1, and 2 ppm), a significant (up to 3-log) reduction was observed at all concentrations, and the effect was time dependent. When exposed to the cyclic monoterpene alone, there were no significant differences between test samples and controls. When exposed to OAF (high and medium concentrations in 0.1 ppm ozone) there were significant differences after 20 min. These reductions were significantly greater than those achieved with ozone alone at 0.1 ppm. OAF is potentially an effective antibacterial agent that can reduce the microbial load in air. Because the technology uses reaction compounds naturally found in the environment, risks to health may be lower than those associated with ozone or other gaseous treatments. However, this hypothesis needs further investigation.

  19. MTHFR Gene Polymorphism-Mutations and Air Pollution as Risk Factors for Breast Cancer

    PubMed Central

    Gonzales, Mildred C.; Yu, Pojui; Shiao, S. Pamela K.

    2017-01-01

    Background The methylenetetrahydrofolate reductase gene (MTHFR) is one of the most investigated genes associated with breast cancer for its role in epigenetic pathways. Objectives The objectives of this metaprediction study were to examine the polymorphism-mutation risk subtypes of MTHFR and air pollution as contributing factors for breast cancer. Methods For triangulation purposes in metapredictive analyses, we used a recursive partition tree, nonlinear association curve fit, and heat maps for data visualization, in addition to the conventional comparison procedure and pooled analyses. Results We included 36,683 breast cancer cases and 40,689 controls across 82 studies for MTHFR 677 and 23,252 cases and 27,094 controls across 50 studies for MTHFR 1298. MTHFR 677 TT was a risk genotype for breast cancer (p = .0004) and in the East Asian subgroup (p = .005). On global maps, the most polymorphism-mutations on MTHFR 677 TT were found in the Middle East, Europe, Asia, and the Americas, whereas the most mutations on MTHFR 1298 CC were located in Europe and the Middle East for the control group. The geographic information system maps further revealed that MTHFR 677 TT mutations yielded a higher risk of breast cancer for Australia, East Asia, the Middle East, South Europe, Morocco, and the Americas and that MTHFR 1298 CC mutations yielded a higher risk in Asia, the Middle East, South Europe, and South America. Metapredictive analysis revealed that air pollution level was significantly associated with MTHFR 677 TT polymorphism-mutation genotype. Discussion We present the most comprehensive analyses to date of MTHFR polymorphism-mutations and breast cancer risk. Future nursing studies are needed to investigate the health impact on breast cancer of epigenetics and air pollution across populations. PMID:28114181

  20. Indentifying the major air pollutants base on factor and cluster analysis, a case study in 74 Chinese cities

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Zhang, Lan-yue; Du, Ming; Zhang, Wei; Huang, Xin; Zhang, Ya-qi; Yang, Yue-yi; Zhang, Jian-min; Deng, Shi-huai; Shen, Fei; Li, Yuan-wei; Xiao, Hong

    2016-11-01

    This article investigated the major air pollutants and its spatial and seasonal distribution in 74 Chinese cities. Factor analysis and Cluster analysis are employed to indentify major factors of air pollutants. The following results are obtained (1) major factors are obtained in spring, summer, autumn, and winter. The first factor in spring includes NO2, PM10, CO, and PM2.5; the first factor in summer and autumn includes PM10, PM2.5, CO and SO2; in winter, the first factor includes NO2, PM10, PM2.5, and SO2. (2) In spring, cities of cluster 5 are the severest polluted by emission sources of SO2, CO, PM10, and PM2.5; the emission sources of O3 would significantly influence the air quality in cities of cluster 2; the emission sources of NO2 could significantly influence the air quality in cities of cluster 3 and cluster 5. (3) In summer, cities of cluster 5 are the severest polluted by automotive emissions and coal flue gas. Cities of cluster 1 are the lightest polluted. Cities of cluster 3 and cluster 2 are polluted by emission sources of SO2 and O3. (4) In Autumn, cities of cluster 3 and 4 are the severest polluted by the emission sources of SO2, CO, PM10, and PM2.5; the emission sources of NO2 would significantly influence the air quality in cities of cluster 5; the emission sources of O3 could significantly influence the air quality in cities of cluster 1 and cluster 4. (5) In winter, cities of cluster 5 are the severest polluted by the emission sources of SO2, CO, PM10, PM2.5, and CO; the emission sources of O3 could significantly influence the air quality in cities of cluster 1 and cluster 5.

  1. Variations of karst underground air temperature induced by various factors (Cave of Županova jama, Central Slovenia)

    NASA Astrophysics Data System (ADS)

    Ravbar, Natasa; Kosutnik, Jure

    2014-04-01

    On the basis of air temperature ( T) monitoring, basic statistical and time series analysis was employed to evaluate thermal states of cave atmosphere variations. Long-term, seasonal and event comparative analysis as well as spectral and cross-correlation analysis was conducted. The results show the relative stability of air T in the isolated part of the cave, whereas variable air T was observed in the parts close to entrances and the surface. The distinctive seasonality in this part of the cave demonstrates that air convection is a driving force for the heat exchange between the cave and the surrounding environment. External air T and heat conducted through the rock walls are also an important factor influencing the cave climate, while heat released by the ice deposit and by water infiltrating through the cave ceiling has a negligible effect. Occasional irregular variations in daily patterns are caused by human impact.

  2. Distinct synoptic patterns and air masses responsible for long-range desert dust transport and sea spray in Palermo, Italy

    NASA Astrophysics Data System (ADS)

    Dimitriou, K.; Paschalidou, A. K.; Kassomenos, P. A.

    2016-09-01

    Undoubtedly, anthropogenic emissions carry a large share of the risk posed on public health by particles exposure in urban areas. However, natural emissions, in the form of desert dust and sea spray, are well known to contribute significantly to the PM load recorded in many Mediterranean environments, posing an extra risk burden on public health. In the present paper, we examine the synoptic climatology in a background station in Palermo, Italy, through K-means clustering of the mean sea-level pressure (MSLP) maps, in an attempt to associate distinct synoptic patterns with increased PM10 levels. Four-day backward trajectory analysis is then applied, in order to study the origins and pathways of air masses susceptible of PM10 episodes. It is concluded that a number of atmospheric patterns result in several kind of flows, namely south, west, and slow-moving/stagnant flows, associated with long-range dust transport and sea spray.

  3. Seasonal variability of tritium and ion concentrations in rain at Kumamoto, Japan and back-trajectory analysis of air mass

    SciTech Connect

    Momoshima, N.; Sugihara, S.; Toyoshima, T.; Nagao, Y.; Takahashi, M.; Nakamura, Y.

    2008-07-15

    Tritium and major ion concentrations in rain were analyzed in Kumamoto (Japan)) between 2001 and 2006 to examine present tritium concentration and seasonal variation. The average tritium concentration was 0.36 {+-} 0.19 Bq/L (n=104) and higher tritium concentrations were observed in spring than the other seasons. Among the ions, non-sea-salt (nss) SO{sub 4}{sup 2}'- showed higher concentration in winter while other ions did not show marked increase in winter. Based on the back-trajectory analyses of air masses, the increase in tritium concentrations in spring arises from downward movement of naturally produced tritium from stratosphere to troposphere, while the increase of the nss-SO{sub 4}{sup 2-} concentrations in winter is due to long range transport of pollutants from China to Japan. (authors)

  4. Air pollution and DNA methylation: interaction by psychological factors in the VA Normative Aging Study.

    PubMed

    Madrigano, Jaime; Baccarelli, Andrea; Mittleman, Murray A; Sparrow, David; Spiro, Avron; Vokonas, Pantel S; Cantone, Laura; Kubzansky, Laura; Schwartz, Joel

    2012-08-01

    DNA methylation is a potential pathway linking air pollution to disease. Studies indicate that psychological functioning modifies the association between pollution and morbidity. The authors estimated the association of DNA methylation with ambient particulate matter less than 2.5 µm in diameter (PM(2.5)) and black carbon, using mixed models. DNA methylation of the inducible nitric oxide synthase gene, iNOS, and the glucocorticoid receptor gene, GCR, was measured by quantitative polymerase chain reaction pyrosequencing of 1,377 blood samples from 699 elderly male participants in the VA Normative Aging Study (1999-2009). The authors also investigated whether this association was modified by psychological factors including optimism or pessimism, anxiety, and depression. iNOS methylation was decreased after acute exposure to both black carbon and PM(2.5). A 1-μg/m(3) increase in exposure to black carbon in the 4 hours preceding the clinical examination was associated with a 0.9% decrease in 5-methylcytosine (95% CI: 0.4, 1.4) in iNOS, and a 10-μg/m(3) increase in exposure to PM(2.5) was associated with a 0.6% decrease in 5-methylcytosine (95% CI: 0.03, 1.1) in iNOS. Participants with low optimism and high anxiety had associations that were 3-4 times larger than those with high optimism or low anxiety. GCR methylation was not associated with particulate air pollution exposure.

  5. Support loss and Q factor enhancement for a rocking mass microgyroscope.

    PubMed

    Wang, Xiong; Xiao, Dingbang; Zhou, Zelong; Wu, Xuezhong; Chen, Zhihua; Li, Shengyi

    2011-01-01

    A rocking mass gyroscope (RMG) is a kind of vibrating mass gyroscope with high sensitivity, whose driving mode and sensing mode are completely uniform. MEMS RMG devices are a research hotspot now because they have the potential to be used in space applications. Support loss is the dominant energy loss mechanism influencing their high sensitivity. An accurate analytical model of support loss for RMGs is presented to enhance their Q factors. The anchor type and support loss mechanism of an RMG are analyzed. Firstly, the support loads, powers flowing into support structure, and vibration energy of an RMG are all developed. Then the analytical model of support loss for the RMG is developed, and its sensitivities to the main structural parameters are also analyzed. High-Q design guidelines for rocking mass microgyroscopes are deduced. Finally, the analytical model is validated by the experimental data and the data from the existing literature. The thicknesses of the prototypes are reduced from 240 μm to 60 μm, while Q factors increase from less than 150 to more than 800. The derived model is general and applicable to various beam resonators, providing significant insight to the design of high-Q MEMS devices.

  6. Characterisation of a smartphone image sensor response to direct solar 305nm irradiation at high air masses.

    PubMed

    Igoe, D P; Amar, A; Parisi, A V; Turner, J

    2017-06-01

    This research reports the first time the sensitivity, properties and response of a smartphone image sensor that has been used to characterise the photobiologically important direct UVB solar irradiances at 305nm in clear sky conditions at high air masses. Solar images taken from Autumn to Spring were analysed using a custom Python script, written to develop and apply an adaptive threshold to mitigate the effects of both noise and hot-pixel aberrations in the images. The images were taken in an unobstructed area, observing from a solar zenith angle as high as 84° (air mass=9.6) to local solar maximum (up to a solar zenith angle of 23°) to fully develop the calibration model in temperatures that varied from 2°C to 24°C. The mean ozone thickness throughout all observations was 281±18 DU (to 2 standard deviations). A Langley Plot was used to confirm that there were constant atmospheric conditions throughout the observations. The quadratic calibration model developed has a strong correlation between the red colour channel from the smartphone with the Microtops measurements of the direct sun 305nm UV, with a coefficient of determination of 0.998 and very low standard errors. Validation of the model verified the robustness of the method and the model, with an average discrepancy of only 5% between smartphone derived and Microtops observed direct solar irradiances at 305nm. The results demonstrate the effectiveness of using the smartphone image sensor as a means to measure photobiologically important solar UVB radiation. The use of ubiquitous portable technologies, such as smartphones and laptop computers to perform data collection and analysis of solar UVB observations is an example of how scientific investigations can be performed by citizen science based individuals and groups, communities and schools.

  7. 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.

  8. Development of portable mass spectrometer with electron cyclotron resonance ion source for detection of chemical warfare agents in air.

    PubMed

    Urabe, Tatsuya; Takahashi, Kazuya; Kitagawa, Michiko; Sato, Takafumi; Kondo, Tomohide; Enomoto, Shuichi; Kidera, Masanori; Seto, Yasuo

    2014-01-01

    A portable mass spectrometer with an electron cyclotron resonance ion source (miniECRIS-MS) was developed. It was used for in situ monitoring of trace amounts of chemical warfare agents (CWAs) in atmospheric air. Instrumental construction and parameters were optimized to realize a fast response, high sensitivity, and a small body size. Three types of CWAs, i.e., phosgene, mustard gas, and hydrogen cyanide were examined to check if the mass spectrometer was able to detect characteristic elements and atomic groups. From the results, it was found that CWAs were effectively ionized in the miniECRIS-MS, and their specific signals could be discerned over the background signals of air. In phosgene, the signals of the 35Cl+ and 37Cl+ ions were clearly observed with high dose-response relationships in the parts-per-billion level, which could lead to the quantitative on-site analysis of CWAs. A parts-per-million level of mustard gas, which was far lower than its lethal dosage (LCt50), was successfully detected with a high signal-stability of the plasma ion source. It was also found that the chemical forms of CWAs ionized in the plasma, i.e., monoatomic ions, fragment ions, and molecular ions, could be detected, thereby enabling the effective identification of the target CWAs. Despite the disadvantages associated with miniaturization, the overall performance (sensitivity and response time) of the miniECRIS-MS in detecting CWAs exceeded those of sector-type ECRIS-MS, showing its potential for on-site detection in the future.

  9. Identification of water-soluble polar organics in air and vehicular emitted particulate matter using ultrahigh resolution mass spectrometry and Capillary electrophoresis - mass spectrometry.

    NASA Astrophysics Data System (ADS)

    Schmitt-Kopplin, P.; Yassine, M.; Gebefugi, I.; Hertkorn, N.; Dabek-Zlotorzynska, E.

    2009-04-01

    The effects of aerosols on human health, atmospheric chemistry, and climate are among the central topics in current environmental health research. Detailed and accurate measurements of the chemical composition of air particulate matter (PM) represent a challenging analytical task. Minute sample amounts are usually composed of several main constituents and hundreds of minor and trace constituents. Moreover, the composition of individual particles can be fairly uniform or very different (internally or externally mixed aerosols), depending on their origin and atmospheric aging processes (coagulation, condensation / evaporation, chemical reaction). The aim of the presentation was the characterization of the organic matter (OM) fraction of environmental aerosols which is not accessible by GC-methods, either because of their high molecular weight, their polarity or due to thermal instability. We also describe the main chemical characteristics of complexe oligomeric organic fraction extracted from different aerosols collected in urban and rural area in Germany and Canada. Mass spectrometry (MS) became an essential tool used by many prominent leaders of the biological research community and the importance of MS to the future of biological research is now clearly evident as in the fields of Proteomics and Metabolomics. Especially Fourier Transform Ion Cyclotron Mass Spectrometry (ICR-FT/MS) is an ultrahigh resolution MS that allows new approach in the analysis of complex mixtures. The mass resolution (< 200 ppb) allowed assigning the elemental composition (C, H, O, N, S…) to each of the obtained mass peaks and thus already a description of the mixture in terms of molecular composition. This possibility is used by the authors together with a high resolution separation method of charged compounds: capillary electrophoresis. A CE-ESI-MS method using an ammonium acetate based background electrolyte (pH 4.7) was developed for the determination of isomeric benzoic acids in

  10. Large-Scale Air Mass Characteristics Observed Over the Remote Tropical Pacific Ocean During March-April 1999: Results from PEM-Tropics B Field Experiment

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Fenn, Marta A.; Butler, Carolyn F.; Grant, William B.; Ismail, Syed; Ferrare, Richard A.; Kooi, Susan A.; Brackett, Vincent G.; Clayton, Marian B.; Avery, Melody A.

    2001-01-01

    Eighteen long-range flights over the Pacific Ocean between 38 S to 20 N and 166 E to 90 W were made by the NASA DC-8 aircraft during the NASA Pacific Exploratory Mission (PEM) Tropics B conducted from March 6 to April 18, 1999. Two lidar systems were flown on the DC-8 to remotely measure vertical profiles of ozone (O3), water vapor (H2O), aerosols, and clouds from near the surface to the upper troposphere along their flight track. In situ measurements of a wide range of gases and aerosols were made on the DC-8 for comprehensive characterization of the air and for correlation with the lidar remote measurements. The transition from northeasterly flow of Northern Hemispheric (NH) air on the northern side of the Intertropical Convergence Zone (ITCZ) to generally easterly flow of Southern Hemispheric (SH) air south of the ITCZ was accompanied by a significant decrease in O3, carbon monoxide, hydrocarbons, and aerosols and an increase in H2O. Trajectory analyses indicate that air north of the ITCZ came from Asia and/or the United States, while the air south of the ITCZ had a long residence time over the Pacific, perhaps originating over South America several weeks earlier. Air south of the South Pacific Convergence Zone (SPCZ) came rapidly from the west originating over Australia or Africa. This air had enhanced O3 and aerosols and an associated decrease in H2O. Average latitudinal and longitudinal distributions of O3 and H2O were constructed from the remote and in situ O3 and H2O data, and these distributions are compared with results from PEM-Tropics A conducted in August-October 1996. During PEM-Tropics B, low O3 air was found in the SH across the entire Pacific Basin at low latitudes. This was in strong contrast to the photochemically enhanced O3 levels found across the central and eastern Pacific low latitudes during PEM-Tropics A. Nine air mass types were identified for PEM-Tropics B based on their O3, aerosols, clouds, and potential vorticity characteristics. The

  11. Development of a thermal desorption-gas chromatography-mass spectrometry method for determining personal care products in air.

    PubMed

    Ramírez, Noelia; Marcé, Rosa Maria; Borrull, Francesc

    2010-06-25

    This study describes the development of a new analytical method for determining 14 personal care products (PCPs) - nine synthetic musks, four parabens and one insect repellent - in air samples. The method is based on active sampling on sorbent tubes and thermal desorption-gas chromatography-mass spectrometry analysis, and is rapid, sensitive and drastically reduces the risk of sample contamination. Three kinds of tubes and traps were tested, those filled with Tenax TA being the most suitable for this study. Method validation showed good repeatability and reproducibility, low detection limits (between 0.03 ng m(-3) for DPMI and 12.5 ng m(-3) for propyl paraben) and good linearity for all compounds. Stability during storage indicated that samples must be kept refrigerated at 4 degrees C and analysed within 1 week of collection. The applicability of the technique to real samples was tested in different indoor and outdoor atmospheres. The total PCP values for indoor air ranged from 135 ng m(-3) in a pharmacy to 2838 ng m(-3) in a hairdresser's, whereas the values for outdoor air ranged from 14 ng m(-3) for a suburban environment to 26 ng m(-3) for an urban environment. In general, the most abundant synthetic musks were galaxolide (5.9-1256 ng m(-3)), musk xylene (1.6-766 ng m(-3)) and tonalide (1.1-138 ng m(-3)). Methyl and ethyl paraben (2.4-313 ng m(-3) and 1.8-117 ng m(-3), respectively) were the most abundant parabens. Although thermal desorption methods have been widely used for determining volatile organic compounds, they are rarely used with semi-volatile compounds. This study thus demonstrates that the thermal desorption method performs well with semi-volatile compounds and, for the first time, that it can be used for determining PCPs.

  12. Association between indoor air pollutant exposure and blood pressure and heart rate in subjects according to body mass index.

    PubMed

    Jung, Chien-Cheng; Su, Huey-Jen; Liang, Hsiu-Hao

    2016-01-01

    This study investigates the effects of high body mass index (BMI) of subjects on individual who exhibited high cardiovascular disease indexes with blood pressure (BP) and heart rate (HR) when exposed to high levels of indoor air pollutants. We collected 115 office workers, and measured their systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR at the end of the workday. The subjects were divided into three groups according to BMI: 18-24 (normal weight), 24-27 (overweight) and >27 (obese). This study also measured the levels of carbon dioxide (CO2), total volatile organic compounds (TVOC), particulate matter with an aerodynamic diameter less than 2.5μm (PM2.5), as well as the bacteria and fungi in the subjects' work-places. The pollutant effects were divided by median. Two-way analysis of variance (ANOVA) was used to analyze the health effects of indoor air pollution exposure according to BMI. Our study showed that higher levels of SBP, DBP and HR occurred in subjects who were overweight or obese as compared to those with normal weight. Moreover, there was higher level of SBP in subjects who were overweight or obese when they were exposed to higher levels of TVOC and fungi (p<0.05). We also found higher value for DBP and HR with increasing BMI to be associated with exposure to higher TVOC levels. This study suggests that individuals with higher BMI have higher cardiovascular disease risk when they are exposed to poor indoor air quality (IAQ), and specifically in terms of TVOC.

  13. Volatile N-nitrosamines in environmental tobacco smoke: Sampling, analysis, emission factors, and indoor air exposures

    SciTech Connect

    Mahanama, K.R.R.; Daisey, J.M.

    1996-05-01

    A more convenient sampling and analysis method for the volatile N-nitrosamines (VNA) in environmental tobacco smoke (ETS), using commercially available Thermosorb/N cartridges, was developed and validated. Using the method, emission factors for the two major VNA in ETS were determined in a room-sized environmental chamber for six commercial cigarette brands, which together accounted for 62.5% of the total market in California in 1990. The average emission factors were 565{+-}115 and 104{+-}20 ng per cigarette for N-nitrosodimethylamine and N-nitrosopyrrolidine, respectively. The emission factors were used to estimate VNA exposures from ETS in a typical office building and an average residence. Indoor concentrations of N,N-dimethylnitrosamine from ETS for these modeled scenarios were less than 10% of the reported median outdoor concentration. This median outdoor concentration, however, includes many measurements made in source-dominated areas and may be considerably higher than one based on more representative sampling of outdoor air. 35 refs., 4 tabs.

  14. Factors Affecting Indoor Air Concentrations of Volatile Organic Compounds at a Site of Subsurface Gasoline Contamination

    SciTech Connect

    Fischer, M.L.; Bentley, A.J.; Dunkin, K.A.; Hodgson, A.T.; Nazaroff, W.W.; Sextro, R.G.; Daisey, J.M.

    1995-11-01

    We report a field study of soil gas transport of volatile organic compounds (VOCs) into a slab-on-grade building found at a site contaminated with gasoline. Although the high VOC concentrations (30-60 g m{sup -3}) measured in the soil gas at depths of 0.7 m below the building suggest a potential for high levels of indoor VOC, the measured indoor air concentrations were lower than those in the soil gas by approximately six orders of magnitude ({approx} 0.03 mg m{sup -3}). This large ratio is explained by (1) the expected dilution of soil gas entering the building via ambient building ventilation (a factor of {approx}1000), and (2) an unexpectedly sharp gradient in soil gas VOC concentration between the depths of 0.1 and 0.7 m (a factor of {approx}1000). Measurements of the soil physical and biological characteristics indicate that a partial physical barrier to vertical transport in combination with microbial degradation provides a likely explanation for this gradient. These factors are likely to be important to varying degrees at other sites.

  15. Scalar K{pi} form factor and light-quark masses

    SciTech Connect

    Jamin, Matthias; Oller, Jose Antonio; Pich, Antonio

    2006-10-01

    Recent experimental improvements on K-decay data allow for a precise extraction of the strangeness-changing scalar K{pi} form factor and the related strange scalar spectral function. On the basis of this scalar as well as the corresponding pseudoscalar spectral function, the strange quark mass is determined to be m{sub s}(2 GeV)=92{+-}9 MeV. Further taking into account chiral perturbation theory mass ratios, the light up and down quark masses turn out to be m{sub u}(2 GeV)=2.7{+-}0.4 MeV as well as m{sub d}(2 GeV)=4.8{+-}0.5 MeV. As a by-product, we also find a value for the Cabibbo angle |V{sub us}|=0.2236(29) and the ratio of meson decay constants F{sub K}/F{sub {pi}}=1.203(16). Performing a global average of the strange mass by including extractions from other channels as well as lattice QCD results yields m{sub s}(2 GeV)=94{+-}6 MeV.

  16. Air flow-assisted ionization imaging mass spectrometry method for easy whole-body molecular imaging under ambient conditions.

    PubMed

    Luo, Zhigang; He, Jiuming; Chen, Yi; He, Jingjing; Gong, Tao; Tang, Fei; Wang, Xiaohao; Zhang, Ruiping; Huang, Lan; Zhang, Lianfeng; Lv, Haining; Ma, Shuanggang; Fu, Zhaodi; Chen, Xiaoguang; Yu, Shishan; Abliz, Zeper

    2013-03-05

    Whole-body molecular imaging is able to directly map spatial distribution of molecules and monitor its biotransformation in intact biological tissue sections. Imaging mass spectrometry (IMS), a label-free molecular imaging method, can be used to image multiple molecules in a single measurement with high specificity. Herein, a novel easy-to-implement, whole-body IMS method was developed with air flow-assisted ionization in a desorption electrospray ionization mode. The developed IMS method can effectively image molecules in a large whole-body section in open air without sample pretreatment, such as chemical labeling, section division, or matrix deposition. Moreover, the signal levels were improved, and the spatial assignment errors were eliminated; thus, high-quality whole-body images were obtained. With this novel IMS method, in situ mapping analysis of molecules was performed in adult rat sections with picomolar sensitivity under ambient conditions, and the dynamic information of molecule distribution and its biotransformation was provided to uncover molecular events at the whole-animal level. A global view of the differential distribution of an anticancer agent and its metabolites was simultaneously acquired in whole-body rat and model mouse bearing neuroglioma along the administration time. The obtained drug distribution provided rich information for identifying the targeted organs and predicting possible tumor spectrum, pharmacological activity, and potential toxicity of drug candidates.

  17. Simulation of solid oxide iron-air battery: Effects of heat and mass transfer on charge/discharge characteristics

    NASA Astrophysics Data System (ADS)

    Ohmori, Hiroko; Iwai, Hiroshi

    2015-07-01

    A time-dependent 2-D numerical simulation was performed on a solid oxide iron-air battery (SOIAB) to reveal the fundamental characteristics of this new system. The SOIAB is a rechargeable battery consisting of a solid oxide electrochemical cell (SOEC) and iron as a redox metal. A simple battery configuration was employed assuming a system with a small capacity. A simulation model for a unit element was developed considering heat and mass transfer in the system, taking both electrochemical and redox reactions into account. The numerical results showed the spatial and temporal changes in the temperature field in the charge and discharge operations, which were due to the combined effects of heat generation/absorption by the electrochemical and redox reactions and heat exchange with the air supplied through convective heat transfer. As the reaction rates are functions of the local temperature, the predicted results show the importance of considering the heat transfer phenomena in this system. It was also found that the active reaction region in the redox metal evolves with time. The nonuniform distribution of iron utilization is affected by the effective gas diffusion coefficients in the porous redox metal, and consequently the change in the current density distribution in the SOEC.

  18. Meteorological factors and air pollution in Lithuanian forests: possible effects on tree condition.

    PubMed

    Ozolincius, Remigijus; Stakenas, Vidas; Serafinaviciute, Brigita

    2005-10-01

    This study investigates changes in tree condition and environmental factors in Lithuania during the active growing season in 1991-2001. The average crown defoliation and the proportion of healthy trees of Pinus sylvestris, Picea abies, Betula sp., Fraxinus excelsior, Alnus incana, Alnus glutinosa, Populus tremula, and Quercus robur, meteorological (average temperature, amount of precipitation, hydrothermal coefficient) and air pollution data (acidity of precipitation, concentrations of SO2, NO2 and exposure of O3) were analysed. During the period 1991-2001 the condition of Pinus sylvestris, Populus tremula showed a tendency of improvement, while defoliation of Fraxinus excelsior significantly increased. The proportion of healthy trees correlated well with the average temperature and O3 (AOT40), while defoliation correlated well with the acidity of precipitation and the concentrations of SO2 and NO2. Deciduous species appeared to be more sensitive to O3 exposure and conifers to the concentrations of SO2 and NO2.

  19. Supplement B to compilation of air pollutant emission factors, volume 1. Stationary point and area sources

    SciTech Connect

    1996-11-01

    This document contains emission factors and process information for more than 200 air pollution source categories. This Supplement to AP-42 addresses pollutant-generating activity from Bituminous And Subbituminous Coal Combustion, Anthracite Coal Combustion, Fuel Oil Combustion, Natural Gas Combustion, Liquefied Petroleum Gas Combustion, Wood Waste Combustion In Boilers, Lignite Combustion, Bagasse Combustion In Sugar Mills, Residential Fireplaces, Residential Wood Stoves, Waste Oil Combustion, Stationary Gas Turbines For Electricity Generation, Heavy-duty Natural Gas-fired Pipeline Compressor Engines And Turbines, Gasoline and Diesel Industrial Engines, Large Stationary Diesel And All Stationary Dual-fuel Engines, Adipic Acid, Cotton Ginning, Alfafalfa Dehydrating, Malt Beverages, Ceramic Products Manufacturing, Electroplating, Wildfires And Prescribed Burning, Emissions From Soils-Greenhouse Gases, Termites-Greenhouse Gases, and Lightning Emissions-Greenhouse Gases.

  20. Prenatal Exposure to Residential Air Pollution and Infant Mental Development: Modulation by Antioxidants and Detoxification Factors

    PubMed Central

    Aguilera, Inmaculada; Ballester, Ferran; Estarlich, Marisa; Fernández-Somoano, Ana; Lertxundi, Aitana; Lertxundi, Nerea; Mendez, Michelle A.; Tardón, Adonina; Vrijheid, Martine; Sunyer, Jordi

    2011-01-01

    Background: Air pollution effects on children’s neurodevelopment have recently been suggested to occur most likely through the oxidative stress pathway. Objective: We aimed to assess whether prenatal exposure to residential air pollution is associated with impaired infant mental development, and whether antioxidant/detoxification factors modulate this association. Methods: In the Spanish INfancia y Medio Ambiente (INMA; Environment and Childhood) Project, 2,644 pregnant women were recruited during their first trimester. Nitrogen dioxide (NO2) and benzene were measured with passive samplers covering the study areas. Land use regression models were developed for each pollutant to predict average outdoor air pollution levels for the entire pregnancy at each residential address. Maternal diet was obtained at first trimester through a validated food frequency questionnaire. Around 14 months, infant mental development was assessed using Bayley Scales of Infant Development. Results: Among the 1,889 children included in the analysis, mean exposure during pregnancy was 29.0 μg/m3 for NO2 and 1.5 μg/m3 for benzene. Exposure to NO2 and benzene showed an inverse association with mental development, although not statistically significant, after adjusting for potential confounders [β (95% confidence interval) = –0.95 (–3.90, 1.89) and –1.57 (–3.69, 0.56), respectively, for a doubling of each compound]. Stronger inverse associations were estimated for both pollutants among infants whose mothers reported low intakes of fruits/vegetables during pregnancy [–4.13 (–7.06, –1.21) and –4.37 (–6.89, –1.86) for NO2 and benzene, respectively], with little evidence of associations in the high-intake group (interaction p-values of 0.073 and 0.047). Inverse associations were also stronger in non-breast-fed infants and infants with low maternal vitamin D, but effect estimates and interactions were not significant. Conclusions: Our findings suggest that prenatal

  1. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  2. Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath.

    PubMed

    Spesyvyi, Anatolii; Smith, David; Španěl, Patrik

    2015-12-15

    A selected ion flow-drift tube mass spectrometric analytical technique, SIFDT-MS, is described that extends the established selected ion flow tube mass spectrometry, SIFT-MS, by the inclusion of a static but variable E-field along the axis of the flow tube reactor in which the analytical ion-molecule chemistry occurs. The ion axial speed is increased in proportion to the reduced field strength E/N (N is the carrier gas number density), and the residence/reaction time, t, which is measured by Hadamard transform multiplexing, is correspondingly reduced. To ensure a proper understanding of the physics and ion chemistry underlying SIFDT-MS, ion diffusive loss to the walls of the flow-drift tube and the mobility of injected H3O(+) ions have been studied as a function of E/N. It is seen that the derived diffusion coefficient and mobility of H3O(+) ions are consistent with those previously reported. The rate coefficient has been determined at elevated E/N for the association reaction of the H3O(+) reagent ions with H2O molecules, which is the first step in the production of H3O(+)(H2O)1,2,3 reagent hydrate ions. The production of hydrated analyte ion was also experimentally investigated. The analytical performance of SIFDT-MS is demonstrated by the quantification of acetone and isoprene in exhaled breath. Finally, the essential features of SIFDT-MS and SIFT-MS are compared, notably pointing out that a much lower speed of the flow-drive pump is required for SIFDT-MS, which facilitates the development of smaller cost-effective analytical instruments for real time breath and fluid headspace analyses.

  3. Measurement error models in chemical mass balance analysis of air quality data

    NASA Astrophysics Data System (ADS)

    Christensen, William F.; Gunst, Richard F.

    The chemical mass balance (CMB) equations have been used to apportion observed pollutant concentrations to their various pollution sources. Typical analyses incorporate estimated pollution source profiles, estimated source profile error variances, and error variances associated with the ambient measurement process. Often the CMB model is fit to the data using an iteratively re-weighted least-squares algorithm to obtain the effective variance solution. We consider the chemical mass balance model within the framework of the statistical measurement error model (e.g., Fuller, W.A., Measurement Error Models, Wiley, NewYork, 1987), and we illustrate that the models assumed by each of the approaches to the CMB equations are in fact special cases of a general measurement error model. We compare alternative source contribution estimators with the commonly used effective variance estimator when standard assumptions are valid and when such assumptions are violated. Four approaches for source contribution estimation and inference are compared using computer simulation: weighted least squares (with standard errors adjusted for source profile error), the effective variance approach of Watson et al. (Atmos, Environ., 18, 1984, 1347), the Britt and Luecke (Technometrics, 15, 1973, 233) approach, and a method of moments approach given in Fuller (1987, p. 193). For the scenarios we consider, the simplistic weighted least-squares approach performs as well as the more widely used effective variance solution in most cases, and is slightly superior to the effective variance solution when source profile variability is large. The four estimation approaches are illustrated using real PM 2.5 data from Fresno and the conclusions drawn from the computer simulation are validated.

  4. Characterisation of the rubber elongation factor from ammoniated latex by electrophoresis and mass spectrometry.

    PubMed

    Dürauer, A; Csaszar, E; Mechtler, K; Jungbauer, A; Schmid, E

    2000-08-18

    Rubber elongation factor (REF) is considered as one of the major allergens present in latex. An extraction and purification protocol for preparation of REF standards has been modified. A protein fraction was extracted from ammoniated latex sap and purified by gel filtration chromatography. The purified and concentrated proteins were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis into two major bands. These bands were further characterised by matrix-assisted laser desorption/ionisation time-of-flight and nano-electrospray ionization mass spectrometry. REF and a truncated form could be ascertained by the mass and fragmentation pattern of the tryptic peptides. In the faster migrating band an additional peptide could be identified. This peptide is also present in Hevb3 and a Mr 27000 latex allergen. Our findings indicate that conventional REF preparations as standards may contain additional allergenic proteins.

  5. Predictors of perceived ambiguity about cancer prevention recommendations: sociodemographic factors and mass media exposures.

    PubMed

    Han, Paul K J; Moser, Richard P; Klein, William M P; Beckjord, Ellen Burke; Dunlavy, Andrea C; Hesse, Bradford W

    2009-12-01

    Cancer prevention recommendations reaching the public today are often ambiguous-that is, of uncertain reliability, credibility, or adequacy-yet little is known about the factors that influence public perceptions of this ambiguity. We used data from the 2005 Health Information National Trends Survey, conducted by the U.S. National Cancer Institute, to explore how sociodemographic characteristics and self-reported mass media exposures relate to perceptions of ambiguity regarding recommendations for the prevention of colon, skin, and lung cancer. Various sociodemographic characteristics (age, education, race) and mass media exposures (television, radio, Internet, health news) were found to be associated with perceived ambiguity about cancer prevention recommendations, and many of these associations varied by cancer type. These findings have important implications for future health communication research and practice.

  6. Pion mass dependence of the K l3 semileptonic scalar form factor within finite volume

    NASA Astrophysics Data System (ADS)

    Ghorbani, K.; Yazdanpanah, M. M.; Mirjalili, A.

    2011-06-01

    We calculate the scalar semileptonic kaon decay in finite volume at the momentum transfer t m =( m K - m π )2, using chiral perturbation theory. At first we obtain the hadronic matrix element to be calculated in finite volume. We then evaluate the finite size effects for two volumes with L=1.83 fm and L=2.73 fm and find that the difference between the finite volume corrections of the two volumes are larger than the difference as quoted in Boyle et al. (Phys. Rev. Lett. 100:141601, 2008). It appears then that the pion masses used for the scalar form factor in ChPT are large which result in large finite volume corrections. If appropriate values for pion mass are used, we believe that the finite size effects estimated in this paper can be useful for lattice data to extrapolate at large lattice size.

  7. Chemical composition of air masses transported from Asia to the U.S. West Coast during ITCT 2K2: Fossil fuel combustion versus biomass-burning signatures

    NASA Astrophysics Data System (ADS)

    de Gouw, J. A.; Cooper, O. R.; Warneke, C.; Hudson, P. K.; Fehsenfeld, F. C.; Holloway, J. S.; Hübler, G.; Nicks, D. K., Jr.; Nowak, J. B.; Parrish, D. D.; Ryerson, T. B.; Atlas, E. L.; Donnelly, S. G.; Schauffler, S. M.; Stroud, V.; Johnson, K.; Carmichael, G. R.; Streets, D. G.

    2004-12-01

    As part of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2), a National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft was used to study the long-range transport of Asian air masses toward the west coast of North America. During research flights on 5 and 17 May, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on 5 and 17 May and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) to propane (C3H8), and, on May 5, the percentage of particles measured by the particle analysis by laser mass spectrometry (PALMS) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast over a range of latitudes and altitudes for the entire ITCT 2K2 period, showed that air masses from Southeast Asia and China were generally observed at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for Southeast Asia. Combined with the origin of the air masses versus altitude, this qualitatively explains the increase with altitude, averaged over the whole ITCT 2K2 period, of the different biomass-burning indicators.

  8. The influence of air temperature inversions on snowmelt and glacier mass-balance simulations, Ammassalik island, SE Greenland

    SciTech Connect

    Mernild, Sebastian Haugard; Liston, Glen

    2009-01-01

    In many applications, a realistic description of air temperature inversions is essential for accurate snow and glacier ice melt, and glacier mass-balance simulations. A physically based snow-evolution modeling system (SnowModel) was used to simulate eight years (1998/99 to 2005/06) of snow accumulation and snow and glacier ice ablation from numerous small coastal marginal glaciers on the SW-part of Ammassalik Island in SE Greenland. These glaciers are regularly influenced by inversions and sea breezes associated with the adjacent relatively low temperature and frequently ice-choked fjords and ocean. To account for the influence of these inversions on the spatiotemporal variation of air temperature and snow and glacier melt rates, temperature inversion routines were added to MircoMet, the meteorological distribution sub-model used in SnowModel. The inversions were observed and modeled to occur during 84% of the simulation period. Modeled inversions were defined not to occur during days with strong winds and high precipitation rates due to the potential of inversion break-up. Field observations showed inversions to extend from sea level to approximately 300 m a.s.l., and this inversion level was prescribed in the model simulations. Simulations with and without the inversion routines were compared. The inversion model produced air temperature distributions with warmer lower elevation areas and cooler higher elevation areas than without inversion routines due to the use of cold sea-breeze base temperature data from underneath the inversion. This yielded an up to 2 weeks earlier snowmelt in the lower areas and up to 1 to 3 weeks later snowmelt in the higher elevation areas of the simulation domain. Averaged mean annual modeled surface mass-balance for all glaciers (mainly located above the inversion layer) was -720 {+-} 620 mm w.eq. y{sup -1} for inversion simulations, and -880 {+-} 620 mm w.eq. y{sup -1} without the inversion routines, a difference of 160 mm w.eq. y

  9. Air mass 1.5 global and direct solar simulation and secondary reference cell calibration using a filtered large area pulsed solar simulator

    NASA Technical Reports Server (NTRS)

    Mueller, Robert L.

    1985-01-01

    Spectral mismatch between a solar simulator and a desired spectrum can result in nearly 20 percent measurement error in the output of photovoltaic devices. This occurs when a crystalline silicon cell monitors the intensity of an unfiltered large area pulsed solar simulator (LAPSS) simulating the ASTM air mass 1.5 direct spectrum and the test device is amorphous silicon. The LAPSS spectral irradiance is modified with readily available glass UV filters to closely match either the ASTM air mass 1.5 direct or global spectrum. Measurement error is reduced to about 1 percent when using either filter if the reference cell and test device are the same general type.

  10. First day of an oil spill on the open sea: early mass transfers of hydrocarbons to air and water.

    PubMed

    Gros, Jonas; Nabi, Deedar; Würz, Birgit; Wick, Lukas Y; Brussaard, Corina P D; Huisman, Johannes; van der Meer, Jan R; Reddy, Christopher M; Arey, J Samuel

    2014-08-19

    During the first hours after release of petroleum at sea, crude oil hydrocarbons partition rapidly into air and water. However, limited information is available about very early evaporation and dissolution processes. We report on the composition of the oil slick during the first day after a permitted, unrestrained 4.3 m(3) oil release conducted on the North Sea. Rapid mass transfers of volatile and soluble hydrocarbons were observed, with >50% of ≤C17 hydrocarbons disappearing within 25 h from this oil slick of <10 km(2) area and <10 μm thickness. For oil sheen, >50% losses of ≤C16 hydrocarbons were observed after 1 h. We developed a mass transfer model to describe the evolution of oil slick chemical composition and water column hydrocarbon concentrations. The model was parametrized based on environmental conditions and hydrocarbon partitioning properties estimated from comprehensive two-dimensional gas chromatography (GC×GC) retention data. The model correctly predicted the observed fractionation of petroleum hydrocarbons in the oil slick resulting from evaporation and dissolution. This is the first report on the broad-spectrum compositional changes in oil during the first day of a spill at the sea surface. Expected outcomes under other environmental conditions are discussed, as well as comparisons to other models.

  11. Polycyclic aromatic hydrocarbons in air on small spatial and temporal scales - II. Mass size distributions and gas-particle partitioning

    NASA Astrophysics Data System (ADS)

    Lammel, Gerhard; Klánová, Jana; Ilić, Predrag; Kohoutek, Jiří; Gasić, Bojan; Kovacić, Igor; Škrdlíková, Lenka

    2010-12-01

    Polycyclic aromatic hydrocarbons (PAHs) were measured together with inorganic air pollutants at two urban sites and one rural background site in the Banja Luka area, Bosnia and Hercegovina, during 72 h in July 2008 using a high time resolution (5 samples per day) with the aim to study gas-particle partitioning, aerosol mass size distributions and to explore the potential of a higher time resolution (4 h-sampling). In the particulate phase the mass median diameters of the PAHs were found almost exclusively in the accumulation mode (0.1-1.0 μm of size). These were larger for semivolatile PAHs than for non-volatile PAHs. Gas-particle partitioning of semivolatile PAHs was strongly influenced by temperature. The results suggest that the Junge-Pankow model is inadequate to explain the inter-species variation and another process must be significant for phase partitioning which is less temperature sensitive than adsorption. Care should be taken when interpreting slopes m of plots of the type log K p = m log p L0 + b based on 24 h means, as these are found sensitive to the time averaging, i.e. tend to be higher than when based on 12 h-mean samples.

  12. The influence of fuel mass load, oxygen supply and burning rate on emission factor and size distribution of carbonaceous particulate matter from indoor corn straw burning

    PubMed Central

    Shen, Guofeng; Xue, Miao; Wei, Siye; Chen, Yuanchen; Wang, Bing; Wang, Rong; Shen, Huizhong; Li, Wei; Zhang, Yanyan; Huang, Ye; Chen, Han; Wei, Wen; Zhao, Qiuyue; Li, Bin; Wu, Haisuo; Tao, Shu

    2014-01-01

    The uncertainty in emission estimation is strongly associated with the variation in emission factor which could be influenced by a variety of factors, like fuel property, stove type, fire management and even methods used in measurements. The impacts of these factors were usually complicated and often interacted with each other. In the present study, controlled burning experiments were conducted to investigate the influence of fuel mass load, air supply and burning rate on the emission of carbonaceous particulate matter (PM) from indoor corn straw burning. Their impacts on PM size distribution were also studied. The results showed that EFs of PM (EFPM), organic carbon (EFOC) and element carbon (EFEC) was independent of the fuel mass load. The differences among them under different burning rates or air supply amounts were also found to be insignificant (p > 0.05) in the tested circumstances. PM from the indoor corn straw burning was dominated by fine PM, and PM with diameter less than 2.1 μm contributed about 86.4±3.9% of the total. The size distribution of PM was also influenced by the burning rate and changed air supply conditions. On average, EFPM, EFOC and EFEC for corn straw burned in a residential cooking stove were 3.84±1.02, 0.846±0.895 and 0.391±0.350 g/kg, respectively. EFPM, EFOC and EFEC were found to be positively correlated with each other, but they were not significantly correlated with EF of co-emitted CO, suggesting a special attention should be paid to the use of CO acting as a surrogate for other incomplete pollutants. PMID:23923424

  13. Relative sensitivity factors for submicron secondary ion mass spectrometry with gallium primary ion beam

    NASA Astrophysics Data System (ADS)

    Satosh, Hitomi; Owari, Masanori; Nihei, Yoshimasa

    1993-08-01

    Relative sensitivity factors (RSFs) of thirteen elements in the oxide glass matrix in secondary ion mass spectrometry (SIMS) excited by a gallium focused ion beam were determined. RSFs were obtained by analyzing powder particles of standard glass samples. Whole volumes of each particles were analyzed in the 'shave-off' mode in order to avoid topographic effects. Reproducibility of RSFs was good, and sample-to-sample scattering of values was relatively small. Dependence of RSFs on the first ionization potential was shown to be reasonable. In order to with the data obtained through the bulk chemical analysis.

  14. Cyclic organic peroxides identification and trace analysis by Raman microscopy and open-air chemical ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pena-Quevedo, Alvaro Javier

    The persistent use of cyclic organic peroxides in explosive devices has increased the interest in study these compounds. Development of methodologies for the detection of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) has become an urgent priority. However, differences in physical properties between cyclic organic peroxides make difficult the development of a general method for peroxide analysis and detection. Following this urgency, the first general technique for the analysis of any peroxide, regarding its structural differences is reported. Characterization and detection of TATP and HMTD was performed using an Open-Air Chemical Ionization High-Resolution Time-of-Flight Mass Spectrometer. The first spectrometric analysis for tetramethylene diperoxide dicarbamide (TMDD) and other nitrogen based peroxides using Raman Microscopy and Mass Spectrometry is reported. Analysis of cyclic peroxides by GC-MS was also conducted to compare results with OACI-HRTOF data. In the OACI mass spectrum, HMTD showed a clear signal at m/z 209 MH + and a small adduct peak at m/z 226 [M+NH4]+ that allowed its detection in commercial standard solutions and lab made standards. TMDD presented a molecular peak of m/z 237 MH+ and an adduct peak of m/z 254 [M+NH4]+. TATP showed a single peak at m/z 240 [M+NH4]+, while the peak of m/z 223 or 222 was completely absent. This evidence suggests that triperoxides are stabilized by the ammonium ion. TATP samples with deuterium enrichment were analyzed to compare results that could differentiate from HMTD. Raman microscopy was used as a complementary characterization method and was an essential tool for cyclic peroxides identification, particularly for those which could not be extensively purified. All samples were characterized by Raman spectroscopy to confirm the Mass Spectrometry results. Peroxide O-O vibrations were observed around 750-970 cm-1. D18-TATP studies had identified ketone triperoxide nu(O-O) vibration around

  15. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  16. PMF receptor modelling of fine and coarse PM 10 in air masses governing monsoon conditions in Hanoi, northern Vietnam

    NASA Astrophysics Data System (ADS)

    Hien, P. D.; Bac, V. T.; Thinh, N. T. H.

    Fine and coarse PM 10 samples collected in Hanoi in 1999-2001 were analysed for black carbon (BC) and water soluble ions (WSI) and measured data were disaggregated according to three types of back trajectories, namely (1) northerly, over inland China, (2) northeasterly, over East China Sea and, (3) southwesterly over Indochina peninsula. Trajectories of types 1, 2 and 3 prevail in September/October-December, January-March/April and May-August, respectively. A source-receptor modelling was performed for each type of trajectories individually using the Positive Matrix Factorisation (PMF) technique. Six or seven sources were extracted for each trajectory type, including soil dust, primary and secondary emissions from local burning (LB), vehicle/road dust, sea salt, Cl-depleted marine aerosols and long-range transport (LRT). LRT contributes little to the coarse mass, but accounts for 50%, 34% and 33% of the fine mass in trajectories of types 1, 2 and 3, respectively. More than two-thirds of the fine mode sulphate are attributed to LRT and associated with ammonium. The comparison of LRT and LB source profiles suggests that air masses arriving from north-northeasterly trajectories are more polluted than those coming from the southwest. Therefore the contribution of LRT's aerosols further enhances the seasonal contrast in the particulate concentration with maximum in winter and minimum in summer. Various mechanisms of sulphate formation in LRT and LB were suggested based on the concentration ratios of [SO 42-]/[K +], [SO 42-]/[BC] and [NH 4+]/[SO 42-] for the two sources.

  17. Soil erosion and causative factors at Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Butterworth, Joel B.

    1988-01-01

    Areas of significant soil erosion and unvegetated road cuts were identified and mapped for Vandenberg Air Force Base. One hundred forty-two eroded areas (most greater than 1.2 ha) and 51 road cuts were identified from recent color infrared aerial photography and ground truthed to determine the severity and causes of erosion. Comparison of the present eroded condition of soils (as shown in the 1986 photography) with that in historical aerial photography indicates that most erosion on the base took place prior to 1928. However, at several sites accelerated rates of erosion and sedimentation may be occurring as soils and parent materials are eroded vertically. The most conspicuous erosion is in the northern part of the base, where severe gully, sheet, and mass movement erosion have occurred in soils and in various sedimentary rocks. Past cultivation practices, compounded by highly erodible soils prone to subsurface piping, are probably the main causes. Improper range management practices following cultivation may have also increased runoff and erosion. Aerial photography from 1986 shows that no appreciable headward erosion or gully sidewall collapse have occurred in this area since 1928.

  18. Influence of Different Factors on Relative Air Humidity in Zaragoza, Spain

    NASA Astrophysics Data System (ADS)

    Cuadrat, José M.

    2015-03-01

    In this study, the spatial patterns of relative air humidity and its relation to urban, geographical and meteorological factors in the city of Zaragoza (Spain) is discussed. We created a relative humidity database by means of 32 urban transects. Data were taken on different days and with different weather types. This data set was used to map the mean spatial distribution of urban dry island (UDI). Using stepwise multiple regression analysis and Landsat ETM+ images the relationships between mean UDI and the main geographic-urban factors: topography, land cover and surface reflectivity, have been analyzed. Different spatial patterns of UDI were determined using Principal Component Analysis (Varimax rotation). The three components extracted accounted for 91% of the total variance. PC1 accounted for the most general patterns (similar to mean UDI); PC2 showed a shift of dry areas to the SE and PC3 a shift to NW. Using data on wind direction in Zaragoza, we have found that the displacement of dry areas to the SE (PC 2) was greater during NW winds while the shift to the NW (PC 3) was produced mainly by SE winds.

  19. Analysis of Factors for Incorporating User Preferences in Air Traffic Management: A system Perspective

    NASA Technical Reports Server (NTRS)

    Sheth, Kapil S.; Gutierrez-Nolasco, Sebastian

    2010-01-01

    This paper presents an analysis of factors that impact user flight schedules during air traffic congestion. In pre-departure flight planning, users file one route per flight, which often leads to increased delays, inefficient airspace utilization, and exclusion of user flight preferences. In this paper, first the idea of filing alternate routes and providing priorities on each of those routes is introduced. Then, the impact of varying planning interval and system imposed departure delay increment is discussed. The metrics of total delay and equity are used for analyzing the impact of these factors on increased traffic and on different users. The results are shown for four cases, with and without the optional routes and priority assignments. Results demonstrate that adding priorities to optional routes further improves system performance compared to filing one route per flight and using first-come first-served scheme. It was also observed that a two-hour planning interval with a five-minute system imposed departure delay increment results in highest delay reduction. The trend holds for a scenario with increased traffic.

  20. The effects of meteorological factors on the occurrence of Ganoderma sp. spores in the air

    NASA Astrophysics Data System (ADS)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2011-03-01

    Ganoderma sp. is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we analysed fungal spore circulation in Szczecin, Poland, and its dependence on meteorological conditions. Statistical models for the airborne spore concentrations of Ganoderma sp.—one of the most abundant fungal taxa in the area—were developed. Aerobiological sampling was conducted over 2004-2008 using a volumetric Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation, maximum and average wind speed, relative humidity and maximum, minimum, average and dew point temperatures. These data were used as the explaining variables. Due to the non-linearity and non-normality of the data set, the applied modelling techniques were artificial neural networks (ANN) and mutlivariate regression trees (MRT). The obtained classification and MRT models predicted threshold conditions above which Ganoderma sp. appeared in the air. It turned out that dew point temperature was the main factor influencing the presence or absence of Ganoderma sp. spores. Further analysis of spore seasons revealed that the airborne fungal spore concentration depended only slightly on meteorological factors.

  1. [Factors associated with academic success of medical students at Buenos Aires University].

    PubMed

    Borracci, Raúl A; Pittaluga, Roberto D; Álvarez Rodríguez, Juan E; Arribalzaga, Eduardo B; Poveda Camargo, Ricardo L; Couto, Juan L; Provenzano, Sergio L

    2014-01-01

    The aim of this study was to identify common factors relating to the academic success of medical students who were distinguished with honors at the Buenos Aires University. In 2011, 142 graduates were surveyed; the questionnaire included 59 questions on their sociodemographic environment, living conditions and social integration, motivation to study, learning capacity and health quality during their career. Compared to other students, these distinguished students more often lived in the city, far from their families; had been educated at private or universitary high schools, their economic needs were financed by their parents, who were on the whole professionals. Most of them were single and childless. The possibility of future employment oportunities (work) did not influence their choice of a medical career, academic success was important to them and they believed that success depended largely on personal effort; they knew how to handle anxiety, were sociable but independent and preferred solid experience to abstract conceptuality in order to obtain information. Our conclusion, within the current system of candidate selection, these results serve to calculate the covert self-selection mechanisms during the career, or in a more restrictive regime, to select those likely to reach academic success due to their privileged ambience. The analysis of demographic factors indicates some degree of inequality for socially disadvantaged students. Perhaps, a selection system based only on intellectual abilities would help identify and support the best candidates regardless of their social context.

  2. Factors associated with H pylori epidemiology in symptomatic children in Buenos Aires, Argentina

    PubMed Central

    Goldman, Cinthia; Barrado, Andrés; Janjetic, Mariana; Balcarce, Norma; Rua, Eduardo Cueto; Oshiro, Masaru; Calcagno, María L; Sarrasague, Margarita Martinez; Fuda, Julián; Weill, Ricardo; Zubillaga, Marcela; Perez-Perez, Guillermo I; Boccio, José

    2006-01-01

    AIM: To determine prevalence of H pylori infection in symptomatic children in Buenos Aires, Argentina, and to investigate factors associated with H pylori positivity. METHODS: A total of 395 children with upper gastrointestinal symptoms referred to the Gastroente-rology Unit of the Children Hospital “Sor Maria Ludovica” were evaluated for the presence of H pylori by the 13C-Urea Breath Test (13C-UBT). A questionnaire was applied to the recruited population. RESULTS: Prevalence of H pylori infection was 40.0% in this population (mean age 9.97 ± 3.1 years). The factors associated with H pylori positivity were number of siblings (P < 0.001), presence of pet cats (P = 0.03) and birds (P = 0.04) in the household, and antecedents of gastritis among family members (P = 0.01). After multivariate analysis, number of siblings [Odds ratio (OR) = 1.39; 95% CI, 1.20-1.61] and contact with pet cats (OR = 1.76; 95% CI, 1.00-3.09) remained as variables associated with H pylori infection. CONCLUSION: The prevalence of H pylori infection in children with upper gastrointestinal symptoms in Argentina was similar to that reported in developed countries. Children from families with a higher crowding index and presence of pet cats have a higher risk of being colonized with H pylori. PMID:16981273

  3. Near-Road Air Quality Monitoring: Factors Affecting Network Design and Interpretation of Data

    EPA Science Inventory

    The growing number of health studies identifying adverse health effects for populations spending significant amounts of time near large roadways has increased the interest in monitoring air quality in this microenvironment. Designing near-road air monitoring networks or interpret...

  4. Emission rates of particle number, mass and black carbon by the Los Angeles International Airport (LAX) and its impact on air quality in Los Angeles

    NASA Astrophysics Data System (ADS)

    Shirmohammadi, Farimah; Sowlat, Mohammad H.; Hasheminassab, Sina; Saffari, Arian; Ban-Weiss, George; Sioutas, Constantinos

    2017-02-01

    This study describes a series of air monitoring measurements of particle number (PN), black carbon (BC) and PM2.5 mass concentrations in the vicinity of the Los Angeles International Airport (LAX) (roughly 150 m downwind of the LAX's south runways) as well as on-road measurements of the aforementioned pollutants using a mobile platform on three major freeways (i.e., I-110, I-105, and I-405) during May-July 2016. All measurements were performed in the "impact zone" of LAX with the predominant westerly winds from coast to inland. The overall impact of aircraft emissions from the LAX airport and its facilities in comparison to vehicular emissions from freeways on air quality was evaluated on a local scale (i.e. areas in the vicinity of the airport). PN concentration was, on average, 4.1 ± 1.2 times greater at the LAX site than on the studied freeways. Particle number emission factors for takeoffs and landings were comparable, with average values of 8.69 ×1015 particles/kg fuel and 8.16 ×1015 particles/kg fuel, respectively, and indicated a nearly 4-fold statistically significant reduction in PN emission factors for takeoffs during the past decade. BC emission factors were 0.12 ± 0.02 and 0.11 ± 0.01 g/kg fuel during takeoffs and landings, respectively. Additionally, the mean PM2.5 emission factor values for takeoffs and landings were also comparable, with values of 0.38 ± 0.04 and 0.40 ± 0.05 g/kg fuel, respectively. Within the impact zone of the airport, an area of roughly 100 km2 downwind of the LAX, measurements indicated that the LAX daily contributions to PN, BC, and PM2.5 were approximately 11, 2.5, and 1.4 times greater than those from the three surrounding freeways. These results underscore the significance of the LAX airport as a major source of pollution within its zone of impact comparing to freeway emissions.

  5. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  6. Urban air pollution and meteorological factors affect emergency department visits of elderly patients with chronic obstructive pulmonary disease in Taiwan.

    PubMed

    Ding, Pei-Hsiou; Wang, Gen-Shuh; Guo, Yue-Leon; Chang, Shuenn-Chin; Wan, Gwo-Hwa

    2017-05-01

    Both air pollution and meteorological factors in metropolitan areas increased emergency department (ED) visits from people with chronic obstructive pulmonary disease (COPD). Few studies investigated the associations between air pollution, meteorological factors, and COPD-related health disorders in Asian countries. This study aimed to investigate the relationship between the environmental factors and COPD-associated ED visits of susceptible elderly population in the largest Taiwanese metropolitan area (Taipei area, including Taipei city and New Taipei city) between 2000 and 2013. Data of air pollutant concentrations (PM10, PM2.5, O3, SO2, NO2 and CO), meteorological factors (daily temperature, relative humidity and air pressure), and daily COPD-associated ED visits were collected from Taiwan Environmental Protection Administration air monitoring stations, Central Weather Bureau stations, and the Taiwan National Health Insurance database in Taipei area. We used a case-crossover study design and conditional logistic regression models with odds ratios (ORs), and 95% confidence intervals (CIs) for evaluating the associations between the environmental factors and COPD-associated ED visits. Analyses showed that PM2.5, O3, and SO2 had significantly greater lag effects (the lag was 4 days for PM2.5, and 5 days for O3 and SO2) on COPD-associated ED visits of the elderly population (65-79 years old). In warmer days, a significantly greater effect on elderly COPD-associated ED visits was estimated for PM2.5 with coexistence of O3. Additionally, either O3 or SO2 combined with other air pollutants increased the risk of elderly COPD-associated ED visits in the days of high relative humidity and air pressure difference, respectively. This study showed that joint effect of urban air pollution and meteorological factors contributed to the COPD-associated ED visits of the susceptible elderly population in the largest metropolitan area in Taiwan. Government authorities should review

  7. Biomass Burning versus Fossil Fuel Combustion Signatures of Air Masses Transported from Asia to the U.S. West Coast during ITCT2k2

    NASA Astrophysics Data System (ADS)

    de Gouw, J.; Cooper, O.; Warneke, C.; Hudson, P.; Brock, C.; Fehsenfeld, F.; Holloway, J.; Huebler, G.; Murphy, D.; Nowak, J.; Parrish, D.; Ryerson, T.; Trainer, M.; Atlas, E.

    2003-12-01

    The goal of the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT2k2) was to study the transport of air pollution from Asia across the Pacific Ocean, and the implications for the background atmospheric composition at the surface in North America. During research flights of the NOAA WP-3 research aircraft on May 5 and 17, strong enhancements of carbon monoxide (CO) and other species were observed in air masses that had been transported from Asia in the free troposphere to North America. The hydrocarbon composition of the air masses indicated that the highest CO levels were related to fossil fuel use. During the flights on May 5, 17 and other days, the levels of several biomass-burning indicators increased with altitude. This was true for acetonitrile (CH3CN), methyl chloride (CH3Cl), the ratio of acetylene (C2H2) versus propane (C3H8), and the percentage of particles measured by the PALMS (particle analysis by laser mass spectrometry) instrument that were attributed to biomass burning based on their carbon and potassium content. An ensemble of back-trajectories, calculated from the U.S. west coast at various latitudes and pressures during the entire ITCT2k2 period, showed that air masses from South-East Asia and China were generally transported at higher altitudes than air from Japan and Korea. Emission inventories estimate the contribution of biomass burning to the total emissions to be low for Japan and Korea, higher for China, and the highest for South-East Asia. Combined with the origin of the air masses versus altitude determined by the back-trajectories, this explains the measured altitude profiles of the biomass burning indicators.

  8. [Variation characteristics and influencing factors of air pollution index in China].

    PubMed

    Li, Xiao-Fei; Zhang, Ming-Jun; Wang, Sheng-Jie; Zhao, Ai-Fang; Ma, Qian

    2012-06-01

    Based on the daily air pollution index (API), primary pollutant, air quality level and status of 42 cities in China during 2001-2010, the characteristics of air quality were analyzed. The results showed that the atmosphere was significantly influenced by consumption of coal. The primary pollutant was PM10, and the air quality status was excellent (0 < API < 50), good (50 < API <100) and slightly polluted (100 < API < 150) in the majority. The air pollution status varied seasonally, which was the most serious in winter, and slightest in summer. The air quality was better and better in the observed period generally; The spatial distribution of urban air environment displayed a worsening trend from the south to the north and from the coasts to the inland; The local emission and natural dust transmission from the Northwest China was the main sources of urban air pollution; The air pollutants were impacted by the meteorological elements, and the air pollution index correlated linearly with precipitation, wind speed and temperature inversion; The distribution of weather conditions, which was affected by the terrain, also could influence the air quality; In addition, the human activities had both positive and negative functions on the urban air quality.

  9. Factors influencing indoor air quality in an urban high rise apartment building (retitled as "Air Pollution and air exchange in an urban high rise apartment building")

    EPA Science Inventory

    The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EP...

  10. Two-loop matching factors for light quark masses and three-loop mass anomalous dimensions in the RI/SMOM schemes

    SciTech Connect

    Sturm, C.; Almeida, L.

    2010-04-26

    Light quark masses can be determined through lattice simulations in regularization invariant momentum-subtraction (RI/MOM) schemes. Subsequently, matching factors, computed in continuum perturbation theory, are used in order to convert these quark masses from a RI/MOM scheme to the {ovr MS} scheme. We calculate the two-loop corrections in QCD to these matching factors as well as the three-loop mass anomalous dimensions for the RI/SMOM and RI/SMOM{sub {gamma}{mu}} schemes. These two schemes are characterized by a symmetric subtraction point. Providing the conversion factors in the two different schemes allows for a better understanding of the systematic uncertainties. The two-loop expansion coefficients of the matching factors for both schemes turn out to be small compared to the traditional RI/MOM schemes. For n{sub f} = 3 quark flavors they are about 0.6%-0.7% and 2%, respectively, of the leading order result at scales of about 2 GeV. Therefore, they will allow for a significant reduction of the systematic uncertainty of light quark mass determinations obtained through this approach. The determination of these matching factors requires the computation of amputated Green's functions with the insertions of quark bilinear operators. As a by-product of our calculation we also provide the corresponding results for the tensor operator.

  11. Two-loop matching factors for light quark masses and three-loop mass anomalous dimensions in the regularization invariant symmetric momentum-subtraction schemes

    SciTech Connect

    Almeida, Leandro G.; Sturm, Christian

    2010-09-01

    Light quark masses can be determined through lattice simulations in regularization invariant momentum-subtraction (RI/MOM) schemes. Subsequently, matching factors, computed in continuum perturbation theory, are used in order to convert these quark masses from a RI/MOM scheme to the MS scheme. We calculate the two-loop corrections in QCD to these matching factors as well as the three-loop mass anomalous dimensions for the RI/SMOM and RI/SMOM{sub {gamma}{sub {mu}} }schemes. These two schemes are characterized by a symmetric subtraction point. Providing the conversion factors in the two different schemes allows for a better understanding of the systematic uncertainties. The two-loop expansion coefficients of the matching factors for both schemes turn out to be small compared to the traditional RI/MOM schemes. For n{sub f}=3 quark flavors they are about 0.6%-0.7% and 2%, respectively, of the leading order result at scales of about 2 GeV. Therefore, they will allow for a significant reduction of the systematic uncertainty of light quark mass determinations obtained through this approach. The determination of these matching factors requires the computation of amputated Green's functions with the insertions of quark bilinear operators. As a by-product of our calculation we also provide the corresponding results for the tensor operator.

  12. Aromatic compound emissions from municipal solid waste landfill: Emission factors and their impact on air pollution

    NASA Astrophysics Data System (ADS)

    Liu, Yanjun; Lu, Wenjing; Guo, Hanwen; Ming, Zhongyuan; Wang, Chi; Xu, Sai; Liu, Yanting; Wang, Hongtao

    2016-08-01

    Aromatic compounds (ACs) are major components of volatile organic compounds emitted from municipal solid waste (MSW) landfills. The ACs emissions from the working face of a landfill in Beijing were studied from 2014 to 2015 using a modified wind tunnel system. Emission factors (EFs) of fugitive ACs emissions from the working face of the landfill were proposed according to statistical analyses to cope with their uncertainty. And their impacts on air quality were assessed for the first time. Toluene was the dominant AC with an average emission rate of 38.8 ± 43.0 μg m-2 s-1 (at a sweeping velocity of 0.26 m s-1). An increasing trend in AC emission rates was observed from 12:00 to 18:00 and then peaked at 21:00 (314.3 μg m-2 s-1). The probability density functions (PDFs) of AC emission rates could be classified into three distributions: Gaussian, log-normal, and logistic. EFs of ACs from the working face of the landfill were proposed according to the 95th percentile cumulative emission rates and the wind effects on ACs emissions. The annual ozone formation and secondary organic aerosol formation potential caused by AC emissions from landfills in Beijing were estimated to be 8.86 × 105 kg year-1 and 3.46 × 104 kg year-1, respectively. Toluene, m + p-xylene, and 1,3,5-trimethylbenzene were the most significant contributors to air pollution. Although ACs pollutions from landfills accounts for less percentage (∼0.1%) compared with other anthropogenic sources, their fugitive emissions which cannot be controlled efficiently deserve more attention and further investigation.

  13. Satellite-based identification of tropopause folding signatures along air mass boundaries

    NASA Astrophysics Data System (ADS)

    Wimmers, Anthony James

    Tropopause folding is a significant though frequently underestimated source of mass exchange between the stratosphere and the troposphere. Although tropopause folds are inherently three-dimensional phenomena, empirical evidence shows that certain signature features in two-dimensional satellite products that are sensitive to tropopause height can be used to infer the vertical layering that characterizes tropopause folds. Both Altered Water Vapor (AWV) imagery and Total Ozone Mapping Spectrometer (TOMS) total ozone reveal significant gradients at the "openings" of tropopause folds, and the direction of the gradient indicates the direction of the intrusion. This is demonstrated empirically with a comparison of the satellite imagery to a data set of aircraft-based ozone lidar transects from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment. Using the data set to optimize the parameters of this empirical relationship, a statistical model is developed to predict the location of tropopause folds based solely on the properties of AWV imagery, which operates on a hemispheric-scale domain and at the approximately 10-km resolution of the GOES water vapor channel. Validation of this model with evidence of tropopause folding from operational radiosonde data was only partially successful; the validation was not reliable enough to provide precise confirmation of the model parameter values, but it did provide some confirmation that the model was well calibrated. Application of this model over a February to May, 2000 time period provides a four-month "climatology" of tropopause folding activity around North America. During this time period, tropopause folding activity was strongest over the northeast Pacific and northwest Atlantic, and at a minimum in the high latitudes around Hudson Bay. Over the entire domain (25--63° N, 40--165° W), tropopause folding activity was greatest in March. This result does not prove that downward vertical transport from

  14. Eutrophication, Ammonia Intoxication, and Infectious Diseases: Interdisciplinary Factors of Mass Mortalities in Cultured Nile Tilapia.

    PubMed

    Abu-Elala, Nermeen M; Abd-Elsalam, Reham M; Marouf, Sherif; Abdelaziz, Mohamed; Moustafa, Mohamed

    2016-09-01

    The present study was designed to assess the possible causes of the mass mortalities of Nile Tilapia Oreochromis niloticus at El-Behera Governorate, Egypt, in relationship to environmental and microbiotic factors. Water samples were collected from fish farms at different locations and from Lake Edku to analyze water temperature, water pH, salinity, biological oxygen demand, dissolved oxygen, total ammonia nitrogen, and un-ionized ammonia. A number of moribund and freshly dead fish were sampled and submitted to our laboratory for microbiological, molecular, and histopathological examination. Water analysis of the fish farms revealed noticeable increases in the previously mentioned physicochemical parameters. Clinical examinations of moribund fish showed severe gill rot and massive external and internal hemorrhages. Ordinary and molecular laboratory findings confirmed the presence of Branchiomyces sp. in gill tissue and mixed bacterial fish pathogens (Streptococcus agalactiae, Vibrio alginolyticus, V. parahaemolyticus, Pseudomonas anguilliseptica, and P. aeruginosa) in visceral organs. The histopathological and transmission electron microscopic examinations revealed severe necrosis of gill filaments and blockage of branchial blood vessels and lamellar capillaries with Branchiomyces sp. hyphae and spores mixed with different shapes of bacteria. Severe inflammations were detected in liver, kidney, heart, and brain tissues. Ultimately, we can conclude that the syndrome of mass fish kills in this area is a consequence of ecological damage to the aquatic environment, which is mainly related to natural and anthropogenic factors, as well as to the presence of infectious agents. Received September 30, 2015; accepted April 12, 2016.

  15. Regulation of pancreatic islet beta-cell mass by growth factor and hormone signaling.

    PubMed

    Huang, Yao; Chang, Yongchang

    2014-01-01

    Dysfunction and destruction of pancreatic islet beta cells is a hallmark of diabetes. Better understanding of cellular signals in beta cells will allow development of therapeutic strategies for diabetes, such as preservation and expansion of beta-cell mass and improvement of beta-cell function. During the past several decades, the number of studies analyzing the molecular mechanisms, including growth factor/hormone signaling pathways that impact islet beta-cell mass and function, has increased exponentially. Notably, somatolactogenic hormones including growth hormone (GH), prolactin (PRL), and insulin-like growth factor-1 (IGF-1) and their receptors (GHR, PRLR, and IGF-1R) are critically involved in beta-cell growth, survival, differentiation, and insulin secretion. In this chapter, we focus more narrowly on GH, PRL, and IGF-1 signaling, and GH-IGF-1 cross talk. We also discuss how these signaling aspects contribute to the regulation of beta-cell proliferation and apoptosis. In particular, our novel findings of GH-induced formation of GHR-JAK2-IGF-1R protein complex and synergistic effects of GH and IGF-1 on beta-cell signaling, proliferation, and antiapoptosis lead to a new concept that IGF-1R may serve as a proximal component of GH/GHR signaling.

  16. QCD factorization for B → ππℓν decays at large dipion masses

    NASA Astrophysics Data System (ADS)

    Böer, Philipp; Feldmann, Thorsten; van Dyk, Danny

    2017-02-01

    We introduce a factorization formula for semi-leptonic b → u transitions in the exclusive decay mode {B}-to {π}+{π}-{ℓ}-{overline{ν}}_{ℓ } in the limit of large pion energies and large dipion invariant mass. One contribution can be described in terms of a universal B → π form factor and the convolution of a short-distance kernel T I with the respective light-cone distribution amplitudes (LCDAs) of the positively charged pion. The second contribution, at leading power, completely factorizes, with a short-distance kernel T II convoluted with the leading-twist LCDAs for both pions and the B-meson. We calculate the leading contributions to the short-distance kernels T I and T II in fixed-order perturbation theory, and discuss the approximate relations among the resulting B → ππ partial-wave form factors. Our results provide useful theoretical constraints for phenomenological models that aim to analyze the complete B → ππℓν phase space.

  17. [Air negative charge ion concentration and its relationships with meteorological factors in different ecological functional zones of Hefei City].

    PubMed

    Wei, Chaoling; Wang, Jingtao; Jiang, Yuelin; Zhang, Qingguo

    2006-11-01

    Air negative charge ion concentration (ANCIC) has a close relationship with air quality. The observations on the ANCIC, sunlight intensity, air temperature, and air relative humidity in different ecological functional zones of Hefei City from 2003 to 2004 showed that the diurnal change pattern of ANCIC was of single peak in sightseeing and habitation zones, dual peak in industrial zone, and complicated in commercial zone. Different ecological functional zones had different appearance time of their daily ANCIC extremum. The diurnal fluctuation of ANCIC was in the order of commercial zone > industrial zone > habitation zone and sightseeing zone. The annual change pattern of ANCIC in these zones was similar, being the highest in summer and lowest in winter, and the mean annual ANCIC was 819, 340, 149 and 126 ions x cm(-3), respectively. The most important meteorological factor affecting the ANCIC in Hefei City was air relative humidity, followed by sunlight intensity and air temperature. There was an exponential relationship between ANCIC and air relative humidity.

  18. Socio-economic factors, lifestyle and gender differences in body mass index in rural India

    PubMed Central

    Barker, Mary; Chorghade, Ginny; Crozier, Sarah; Leary, Sam; Fall, Caroline

    2007-01-01

    A survey of the nutritional status of women in six villages in the Pune district of Maharashtra, India found young women to have significantly lower body mass index (BMI) than their male peers. The purpose of this study was to identify social and economic factors associated with this difference in thinness, and to explore the behaviour in men and women that might underlie these associations. We compared men and women in 90 families in this part of Maharashtra, recording social and economic details, fasting practices and oil consumption, and took measurements of the height and weight of a married couple of child-bearing age in each family. In this agricultural community, women were thinner in joint, land-owning families where the main occupation was farming, than they did in non-farming families. This was not true of men in this type of family. Men in ‘cash-rich’ families had higher BMIs than men in families without this characteristic. There was no corresponding difference in women’s body mass index. We then examined the lifestyles of men and women in a sub-set of 45 of these families. Women were more likely to work full-time in farming than men, to carry the burden of all household chores, to have less sleep and to eat less food away from home than men. Women fasted more frequently and more strictly than men. Despite identifying significant differences in behaviour between men and women in the same household, we could find no direct link between behaviour and body mass index. We conclude that being married into a farming family is an important factor in determining the thinness of a woman in rural Maharashtra. PMID:17116720

  19. Validation and Application of the Mass Balance Model To Determine the Effectiveness of Portable Air Purifiers in Removing Ultrafine and Submicrometer Particles in an Apartment.

    PubMed

    Lee, Wan-Chen; Catalano, Paul J; Yoo, Jun Young; Park, Chan Jung; Koutrakis, Petros

    2015-08-18

    We validated the use of the mass balance model to determine the effectiveness of portable air purifiers in removing ultrafine (<0.10 μm) and submicrometer particles (0.10-0.53 μm) in an apartment. We evaluated two identical portable air purifiers, equipped with high efficiency particulate air filters, for their performance under three different air flow settings and three target air exchange rates: 0.60, 0.90, and 1.20 h(-1). We subsequently used a mixed effects model to estimate the slope between the measured and modeled effectiveness by particle size. Our study showed that effectiveness was highly particle size-dependent. For example, at the lowest target air exchange rate, it ranged from 0.33 to 0.56, 0.51 to 0.75, and 0.60 to 0.81 for the three air purifier flow settings, respectively. Our findings suggested that filtration was the dominant removal mechanism for submicrometer particles, whereas deposition could play a more important role in ultrafine particle removal. We found reasonable agreement between measured and modeled effectiveness with size-resolved slopes ranging from 1.11 ± 0.06 to 1.25 ± 0.07 (mean ± SE), except for particles <35 nm. Our study design can be applied to investigate the performances of other portable air purifiers as well as the influences of various parameters on effectiveness in different residential settings.

  20. Hygroscopic growth of particles nebulized from water-soluble extracts of PM2.5 aerosols over the Bay of Bengal: Influence of heterogeneity in air masses and formation pathways.

    PubMed

    Boreddy, S K R; Kawamura, Kimitaka; Bikkina, Srinivas; Sarin, M M

    2016-02-15

    Hygroscopic properties of water-soluble matter (WSM) extracted from fine-mode aerosols (PM2.5) in the marine atmospheric boundary layer of the Bay of Bengal (BoB) have been investigated during a cruise from 27th December 2008 to 30th January 2009. Hygroscopic growth factors were measured on particles generated from the WSM using an H-TDMA system with an initial dry size of 100 nm in the range of 5-95% relative humidity (RH). The measured hygroscopic growth of WSM at 90% RH, g(90%)WSM, were ranged from 1.11 to 1.74 (mean: 1.43 ± 0.19) over the northern BoB and 1.12 to 1.38 (mean: 1.25 ± 0.09) over the southern BoB. A key finding is that distinct hygroscopic growth factors are associated with the air masses from the Indo-Gangetic plains (IGP), which are clearly distinguishable from those associated with air masses from Southeast Asia (SEA). We found higher (lower) g(90%)WSM over the northern (southern) BoB, which were associated with an IGP (SEA) air masses, probably due the formation of high hygroscopic salts such as (NH4)2SO4. On the other hand, biomass burning influenced SEA air masses confer the low hygroscopic salts such as K2SO4, MgSO4, and organic salts over the southern BoB. Interestingly, mass fractions of water-soluble organic matter (WSOM) showed negative and positive correlations with g(90%)WSM over the northern and southern BoB, respectively, suggesting that the mixing state of organic and inorganic fractions could play a major role on the g(90%)WSM over the BoB. Further, WSOM/SO4(2-) mass ratios suggest that SO4(2-) dominates the g(90%)WSM over the northern BoB whereas WSOM fractions were important over the southern BoB. The present study also suggests that aging process could significantly alter the hygroscopic growth of aerosol particles over the BoB, especially over the southern BoB.

  1. Remote sensing observations for monitoring and mathematical simulations of transboundary air pollutants migration from Siberian mass wildfires to Kazakhstan

    NASA Astrophysics Data System (ADS)

    Kaipov, I. V.

    2017-03-01

    Anthropogenic and natural factors have increased the power of wildfires in massive Siberian woodlands. As a consequence, the expansion of burned areas and increase in the duration of the forest fire season have led to the release of significant amounts of gases and aerosols. Therefore, it is important to understand the impact of wildland fires on air quality, atmospheric composition, climate and accurately describe the distribution of combustion products in time and space. The most effective research tool is the regional hydrodynamic model of the atmosphere, coupled with the model of pollutants transport and chemical interaction. Taking into account the meteorological parameters and processes of chemical interaction of impurities, complex use of remote sensing techniques for monitoring massive forest fires and mathematical modeling of long-range transport of pollutants in the atmosphere, allow to evaluate spatial and temporal scale of the phenomenon and calculate the quantitative characteristics of pollutants depending on the height and distance of migration.

  2. Air mass origin signals in δ 18O of tree-ring cellulose revealed by back-trajectory modeling at the monsoonal Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Wernicke, Jakob; Hochreuther, Philipp; Grießinger, Jussi; Zhu, Haifeng; Wang, Lily; Bräuning, Achim

    2016-12-01

    A profound consideration of stable oxygen isotope source water origins is a precondition for an unambiguous palaeoenvironmental interpretation of terrestrial δ 18O archives. To stress the influence of air mass origins on widely used δ 18O tree-ring chronologies, we conducted correlation analyses between six annually resolved δ 18O tree-ring cellulose ( δ ^{18}O_{TC}) chronologies and mean annual air package origins obtained from backward trajectory modeling. This novel approach has been tested for a transect at the southeastern Tibetan plateau (TP), where air masses with different isotopic composition overlap. Detailed examinations of daily precipitation amounts and monthly precipitation δ 18O values ( δ ^{18}OP) were conducted with the ERA Interim and Laboratoire de Météorologie Dynamique General Circulation Model (LMDZiso) data, respectively. Particularly the southernmost study sites are influenced by a distinct amount effect. Here, air package origin δ ^{18}O_{TC} relations are generally weaker in contrast to our northern located study sites. We found that tree-ring isotope signatures at dry sites with less rain days per year tend to be influenced stronger by air mass origin than tree-ring isotope values at semi-humid sites. That implies that the local hydroclimate history inferred from δ ^{18}O_{TC} archives is better recorded at semi-humid sites.

  3. Combining Experiments and Simulation of Gas Absorption for Teaching Mass Transfer Fundamentals: Removing CO2 from Air Using Water and NaOH

    ERIC Educational Resources Information Center

    Clark, William M.; Jackson, Yaminah Z.; Morin, Michael T.; Ferraro, Giacomo P.

    2011-01-01

    Laboratory experiments and computer models for studying the mass transfer process of removing CO2 from air using water or dilute NaOH solution as absorbent are presented. Models tie experiment to theory and give a visual representation of concentration profiles and also illustrate the two-film theory and the relative importance of various…

  4. REAL TIME, ON-LINE CHARACTERIZATION OF DIESEL GENERATOR AIR TOXIC EMISSIONS BY RESONANCE ENHANCED MULTI-PHOTON IONIZATION TIME OF FLIGHT MASS SPECTROMETRY

    EPA Science Inventory

    The laser based resonance, enhanced multi-photon ionization time-of-flight mass spectrometry (REMPI-TOFMS) technique has been applied to the exhaust gas stream of a diesel generator to measure, in real time, concentration levels of aromatic air toxics. Volatile organic compounds ...

  5. The aryl hydrocarbon receptor AhR links atopic dermatitis and air pollution via induction of the neurotrophic factor artemin.

    PubMed

    Hidaka, Takanori; Ogawa, Eisaku; Kobayashi, Eri H; Suzuki, Takafumi; Funayama, Ryo; Nagashima, Takeshi; Fujimura, Taku; Aiba, Setsuya; Nakayama, Keiko; Okuyama, Ryuhei; Yamamoto, Masayuki

    2017-01-01

    Atopic dermatitis is increasing worldwide in correlation with air pollution. Various organic components of pollutants activate the transcription factor AhR (aryl hydrocarbon receptor). Through the use of AhR-CA mice, whose keratinocytes express constitutively active AhR and that develop atopic-dermatitis-like phenotypes, we identified Artn as a keratinocyte-specific AhR target gene whose product (the neurotrophic factor artemin) was responsible for epidermal hyper-innervation that led to hypersensitivity to pruritus. The activation of AhR via air pollutants induced expression of artemin, alloknesis, epidermal hyper-innervation and inflammation. AhR activation and ARTN expression were positively correlated in the epidermis of patients with atopic dermatitis. Thus, AhR in keratinocytes senses environmental stimuli and elicits an atopic-dermatitis pathology. We propose a mechanism of air-pollution-induced atopic dermatitis via activation of AhR.

  6. Determination of trichloroanisole and trichlorophenol in wineries' ambient air by passive sampling and thermal desorption-gas chromatography coupled to tandem mass spectrometry.

    PubMed

    Camino-Sánchez, F J; Bermúdez-Peinado, R; Zafra-Gómez, A; Ruíz-García, J; Vílchez-Quero, J L

    2015-02-06

    The present paper describes the calibration of selected passive samplers used in the quantitation of trichlorophenol and trichloroanisole in wineries' ambient air, by calculating the corresponding sampling rates. The method is based on passive sampling with sorbent tubes and involves thermal desorption-gas chromatography-triple quadrupole mass spectrometry analysis. Three commercially available sorbents were tested using sampling cartridges with a radial design instead of axial ones. The best results were found for Tenax TA™. Sampling rates (R-values) for the selected sorbents were determined. Passive sampling was also used for accurately determining the amount of compounds present in the air. Adequate correlation coefficients between the mass of the target analytes and exposure time were obtained. The proposed validated method is a useful tool for the early detection of trichloroanisole and its precursor trichlorophenol in wineries' ambient air while avoiding contamination of wine or winery facilities.

  7. Determination of benzene at trace levels in air by a novel method based on solid-phase microextraction gas chromatography/mass spectrometry.

    PubMed

    Saba, A; Cuzzola, A; Raffaelli, A; Pucci, S; Salvadori, P

    2001-01-01

    A new method for the determination of benzene at trace levels in air is presented. The method consists of the collection of air samples on adsorbent cartridges with simultaneous adsorption of pre-established amounts of D6-labeled internal standard. Desorption from the cartridge is performed by solid-phase microextraction (SPME) with analysis by gas chromatography/mass spectrometry (GC/MS) using an ion trap mass spectrometer. The influence of several parameters (type of SPME fiber, temperature, time, for example) was investigated, and good linearity in the range 10-400 ng of C6D6, with a coefficient of variance (CV) around 3-5%, was obtained. The method was tested by sampling air in a town center in Italy, and a benzene concentration of approximately 50 microg/m(3) was determined. The maximum limit recommended by the European Community is 10 microg/m(3).

  8. Transport Regimes of Air Masses Affecting the Tropospheric Composition of the Canadian and European Arctic During RACEPAC 2014 and NETCARE 2014/2015

    NASA Astrophysics Data System (ADS)

    Bozem, H.; Hoor, P. M.; Koellner, F.; Kunkel, D.; Schneider, J.; Schulz, C.; Herber, A. B.; Borrmann, S.; Wendisch, M.; Ehrlich, A.; Leaitch, W. R.; Willis, M. D.; Burkart, J.; Thomas, J. L.; Abbatt, J.

    2015-12-01

    The Arctic is warming much faster than any other place in the world and undergoes a rapid change dominated by a changing climate in this region. The impact of polluted air masses traveling to the Arctic from various remote sources significantly contributes to the observed climate change, in contrast there are additional local emission sources contributing to the level of pollutants (trace gases and aerosol). Processes affecting the emission and transport of these pollutants are not well understood and need to be further investigated. We present aircraft based trace gas measurements in the Arctic during RACEPAC (2014) and NETCARE (2014 and 2015) with the Polar 6 aircraft of Alfred Wegener Institute (AWI) covering an area from 134°W to 17°W and 68°N to 83°N. We focus on cloud, aerosol and general transport processes of polluted air masses into the high Arctic. Based on CO and CO2 measurements and kinematic 10-day back trajectories we analyze the transport regimes prevalent during spring (RACEPAC 2014 and NETCARE 2015) and summer (NETCARE 2014) in the observed region. Whereas the eastern part of the Canadian Arctic is affected by air masses with their origin in Asia, in the central and western parts of the Canadian and European Arctic air masses from North America are predominant at the time of the measurement. In general the more northern parts of the Arctic were relatively unaffected by pollution from mid-latitudes since air masses mostly travel within the polar dome, being quite isolated. Associated mixing ratios of CO and CO2 fit into the seasonal cycle observed at NOAA ground stations throughout the Arctic, but show a more mid-latitudinal characteristic at higher altitudes. The transition is remarkably sharp and allows for a chemical definition of the polar dome. At low altitudes, synoptic disturbances transport polluted air masses from mid-latitudes into regions of the polar dome. These air masses contribute to the Arctic pollution background, but also

  9. Comparison of road traffic emission factors and testing by comparison of modelled and measured ambient air quality data.

    PubMed

    Peace, H; Owen, B; Raper, D W

    2004-12-01

    This paper describes a comparison of three different sets of road traffic emission factors released by the UK government for use in air quality review and assessment. The air quality management process of review and assessment began in 1997 in the UK. During this period of ongoing review and assessment, a number of changes have been made to the emission factors provided by the government. The use of different sets of emission factors during the assessment process has lead to some inconsistencies between results from neighbouring local authorities and also between different modelling exercises undertaken by the same local authorities. One purpose of this study has been to compare three different sets of emission factors, including the most recent set, and to some degree highlight the uncertainty associated with the use of factors, such as the shift of emphasis in terms of emissions from cars to heavy goods vehicles. The most recently released emission factors are the most comprehensive to date, and theoretically more accurate than previous sets due to the larger database of emission measurements that they have been based on. Therefore, the most recent set of emission factors have been additionally used in a validation exercise between modelled and monitored data. Comparison has been undertaken with monitoring data at a variety of urban background, urban centre and roadside sites. This work has shown some differences between the predicted trends in emission factors and measured trends in ambient air pollution levels, especially at roadside sites, indicating an under-prediction of the air pollution contribution from road traffic.

  10. A Study of the Physiological Factors Affecting the Nature of the Adult Learner in the Phoenix Air National Guard.

    ERIC Educational Resources Information Center

    Torbert, James Brison

    An investigation reviewed current literature in the field of physiological factors affecting the adult learning environment. These findings were compared to the academic learning environment at the Phoenix Air National Guard. The end product was a set of recommendations for management to implement in order to improve the learning climate for the…

  11. Formic and Acetic Acid Observations over Colorado by Chemical Ionization Mass Spectrometry and Organic Acids' Role in Air Quality

    NASA Astrophysics Data System (ADS)

    Treadaway, V.; O'Sullivan, D. W.; Heikes, B.; Silwal, I.; McNeill, A.

    2015-12-01

    Formic acid (HFo) and acetic acid (HAc) have both natural and anthropogenic sources and a role in the atmospheric processing of carbon. These organic acids also have an increasing importance in setting the acidity of rain and snow as precipitation nitrate and sulfate concentrations have decreased. Primary emissions for both organic acids include biomass burning, agriculture, and motor vehicle emissions. Secondary production is also a substantial source for both acids especially from biogenic precursors, secondary organic aerosols (SOAs), and photochemical production from volatile organic compounds (VOCs) and oxygenated volatile organic compounds (OVOCs). Chemical transport models underestimate organic acid concentrations and recent research has sought to develop additional production mechanisms. Here we report HFo and HAc measurements during two campaigns over Colorado using the peroxide chemical ionization mass spectrometer (PCIMS). Iodide clusters of both HFo and HAc were recorded at mass-to-charge ratios of 173 and 187, respectively. The PCIMS was flown aboard the NCAR Gulfstream-V platform during the Deep Convective Clouds and Chemistry Experiment (DC3) and aboard the NCAR C-130 during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE). The DC3 observations were made in May and June 2012 extending from the surface to 13 km over the central and eastern United States. FRAPPE observations were made in July and August 2014 from the surface to 7 km over Colorado. DC3 measurements reported here are focused over the Colorado Front Range and complement the FRAPPE observations. DC3 HFo altitude profiles are characterized by a decrease up to 6 km followed by an increase either back to boundary layer mixing ratio values or higher (a "C" shape). Organic acid measurements from both campaigns are interpreted with an emphasis on emission sources (both natural and anthropogenic) over Colorado and in situ photochemical production especially ozone precursors.

  12. Polybrominated diphenyl ethers in sewage sludge and treated biosolids: effect factors and mass balance.

    PubMed

    Kim, M; Guerra, P; Theocharides, M; Barclay, K; Smyth, S A; Alaee, M

    2013-11-01

    Polybrominated diphenyl ether (PBDE) flame retardants have been consistently detected in sewage sludge and treated biosolids. Two hundred and eighty-eight samples including primary sludge (PS), waste biological sludge (WBS) and treated biosolids from fifteen wastewater treatment plants (WWTPs) in Canada were analyzed to investigate the factors affecting accumulation of PBDEs in sludge and biosolids. Factors examined included environmental/sewershed conditions and operational parameters of the WWTPs. PBDE concentrations in PS, WBS and treated biosolids were 230-82,000 ng/g, 530-8800 ng/g and 420-6000 ng/g, respectively; BDE-209,-99, and -47 were the predominant congeners. Concentrations were influenced by industrial input, leachate, and temperature. Several examinations including the measurement of BDE-202 indicated minimal debromination during wastewater treatment. Estimated solids-liquid distribution coefficients were moderately correlated to hydraulic retention time, solids loading rate, mixed liquor suspended solids, solids retention time, and removal of organic solids, indicating that PBDE partitioning to solids can be optimized by WWTPs' operational conditions. Solids treatment type strongly affected PBDE levels in biosolids: 1.5 times increase after solids digestion, therefore, digestion efficiency could be a potential factor for variability of PBDEs concentration. In contrast, alkaline treatment reduced PBDE concentrations in biosolids. Overall, mass balance approaches confirmed that PBDEs were removed from the liquid stream through partitioning to solids. Variability of PBDE levels in biosolids could result in different PBDEs burdens to agricultural land, and different exposure levels to soil organisms.

  13. Influencing Factors of the Body Mass Index of Elementary Students in Southern Taiwan

    PubMed Central

    Chou, Li-Na; Chen, Min-Li

    2017-01-01

    The body mass index (BMI) of school children in Taiwan is markedly increasing. According to statistical data from the Taiwan Ministry of Education, the prevalence of obesity in school children from the southern part of the country is the highest in Taiwan. Thus, exploring the factors influencing BMI in elementary school children from southern Taiwan is crucial. This study investigated the influencing factors including physical activity levels, sedentary behaviors, dietary habits, and perceived body shape on the BMIs of elementary school children from southern Taiwan. A cross-sectional design was used, and the participants consisted of 3251 fifth-grade students (1628 boys, 50.1%; 1623 girls, 49.9%). The average BMI values for boys and girls were 19.69 and 18.70 (kg/cm) respectively. Statistically significant associations were observed between BMI and sex, 31–60 min of daily vigorous or moderate physical activities levels, length of time spent watching television, time spent on video games or the computer, and intake of vegetable or meat gravy with rice (p < 0.001). Perceived body shape also affected the BMI of school children. The results of this study enable educational institutions in Taiwan to understand the factors affecting the BMI of school children and use this information as the basis for future healthy body weight policies. PMID:28241506

  14. Human factors issues in the use of artificial intelligence in air traffic control. October 1990 Workshop

    NASA Technical Reports Server (NTRS)

    Hockaday, Stephen; Kuhlenschmidt, Sharon (Editor)

    1991-01-01

    The objective of the workshop was to explore the role of human factors in facilitating the introduction of artificial intelligence (AI) to advanced air traffic control (ATC) automation concepts. AI is an umbrella term which is continually expanding to cover a variety of techniques where machines are performing actions taken based upon dynamic, external stimuli. AI methods can be implemented using more traditional programming languages such as LISP or PROLOG, or they can be implemented using state-of-the-art techniques such as object-oriented programming, neural nets (hardware or software), and knowledge based expert systems. As this technology advances and as increasingly powerful computing platforms become available, the use of AI to enhance ATC systems can be realized. Substantial efforts along these lines are already being undertaken at the FAA Technical Center, NASA Ames Research Center, academic institutions, industry, and elsewhere. Although it is clear that the technology is ripe for bringing computer automation to ATC systems, the proper scope and role of automation are not at all apparent. The major concern is how to combine human controllers with computer technology. A wide spectrum of options exists, ranging from using automation only to provide extra tools to augment decision making by human controllers to turning over moment-by-moment control to automated systems and using humans as supervisors and system managers. Across this spectrum, it is now obvious that the difficulties that occur when tying human and automated systems together must be resolved so that automation can be introduced safely and effectively. The focus of the workshop was to further explore the role of injecting AI into ATC systems and to identify the human factors that need to be considered for successful application of the technology to present and future ATC systems.

  15. Overweight, air and noise pollution: Universal risk factors for pediatric pre-hypertension

    PubMed Central

    Kelishadi, Roya; Poursafa, Parinaz; Keramatian, Kasra

    2011-01-01

    Pediatric pre-hypertension (pre-HTN) has a complex multifactorial etiology. Although most cases are secondary to other disorders, a substantial number of children and adolescents have primary or essential HTN and pre-HTN. The gene-gene and gene-environment interactions should be considered in this context. The strong relationship of pre-HTN with environmental factors such as air pollution, noise pollution and passive smoking and obesity suggest that its prevalence will be escalating. Exposure to ambient particulate matters may increase blood pressure (BP) within hours to days. The underlying biologic pathways include autonomic nervous system imbalance and arterial vascular dysfunction or vasoconstriction because of systemic oxidative stress and inflammation. Likewise, tobacco smoke exposure of pregnant mothers increases systolic BP of their offspring in early infancy. Parental smoking also independently affects systolic BP among healthy preschool children. Noise exposure, notably in night, is associated with catecholamine secretion, increased BP and a pre-HTN state even in pre-school age children. Excess weight is associated with dysfunction of the adipose tissue, consisting of enlarged hypertrophied adipocytes, increased infiltration by macrophages and variations in secretion of adipokines and free fatty acids. These changes would result in chronic vascular inflammation, oxidative stress, activation of the renin-angiotensin-aldosterone system and sympathetic response, and ultimately to pre-HTN from childhood. Prevention and control of the modifiable risk factors of pre-HTN from prenatal period can have long-term health impact on primordial and primary prevention of chronic non-communicable diseases. This review presents a general view on the diagnosis, prevalence and etiology of pre-HTN along with practical measures for its prevention and control. PMID:22973395

  16. Optimization of automated gas sample collection and isotope ratio mass spectrometric analysis of delta(13)C of CO(2) in air.

    PubMed

    Zeeman, Matthias J; Werner, Roland A; Eugster, Werner; Siegwolf, Rolf T W; Wehrle, Günther; Mohn, Joachim; Buchmann, Nina

    2008-12-01

    The application of (13)C/(12)C in ecosystem-scale tracer models for CO(2) in air requires accurate measurements of the mixing ratios and stable isotope ratios of CO(2). To increase measurement reliability and data intercomparability, as well as to shorten analysis times, we have improved an existing field sampling setup with portable air sampling units and developed a laboratory setup for the analysis of the delta(13)C of CO(2) in air by isotope ratio mass spectrometry (IRMS). The changes consist of (a) optimization of sample and standard gas flow paths, (b) additional software configuration, and (c) automation of liquid nitrogen refilling for the cryogenic trap. We achieved a precision better than 0.1 per thousand and an accuracy of 0.11 +/- 0.04 per thousand for the measurement of delta(13)C of CO(2) in air and unattended operation of measurement sequences up to 12 h.

  17. Assessment of climatic factors influence on interannual changes in the global surface air temperature

    NASA Astrophysics Data System (ADS)

    Gusakova, Maria; Karlin, Lev

    2014-05-01

    A model to assess a number of factors such as TSI, albedo, cloudiness and greenhouse gases including water vapour affecting global surface air temperature (SAT) changes has been developed. To develop the model solar energy transformation in the atmosphere and the other radiation fluxes transformation were investigated. It's a common knowledge that some part of the incoming solar energy is reflected into space by the Earth's surface, aerosol and cloud particles. A contribution of these components to changes in the reflected solar energy was assessed on the basis of developed linear parameterization. During the period of 2001 - 2010, clouds were found to be the basic contributor to the changes in reflected shortwave radiation. Some part of outgoing terrestrial radiation is retained in the atmosphere by greenhouse gases, water vapour and cloudiness. A contribution of these components to changes in the absorbed longwave radiation was assessed on the basis of developed linear parameterization. It was estimated that the contribution of water vapour was dominant during the analyzed period. The developed parameterization of global albedo made it possible to assess the contribution of TSI to global SAT changes. Making use of the parameterizations listed above the model has been improved. The model calculations showed that the our projections of global SAT to 2030 were lower than IPCC estimates.

  18. Perpetual factors involved in performance of air traffic controllers using a microwave landing system

    NASA Technical Reports Server (NTRS)

    Gershzohn, G.

    1978-01-01

    The task involved the control of two simulated aircraft targets per trial, in a 37.0 -km radius terminal area, by means of conventional radar vectoring and/or speed control. The goal was to insure that the two targets crossed the Missed Approach Point (MAP) at the runway threshold exactly 60 sec apart. The effects on controller performance of the MLS configuration under wind and no-wind conditions were examined. The data for mean separation time between targets at the MAP and the range about that mean were analyzed by appropriate analyses of variance. Significant effects were found for mean separation times as a result of the configuration of the MLS and for interaction between the configuration and wind conditions. The analysis of variance for range indicated significantly poorer performance under the wind condition. These findings are believed to be a result of certain perceptual factors involved in radar air traffic control (ATC) using the MLS with separation of targets in time.

  19. Student understanding of the volume, mass, and pressure of air within a sealed syringe in different states of compression

    NASA Astrophysics Data System (ADS)

    de Berg, Kevin Charles

    Problem-solving strategies in the physical sciences have been characterized by a dependence on algorithmic techniques often devoid of any reasoning skills. The purpose of this study was to examine student responses to a task relating to Boyle's Law for gases, which did not demand the use of a mathematical equation for its solution. Students (17- to 18-year-olds) in lower sixth form from two colleges in the Leeds district of Yorkshire in England were asked to respond to a task relating to pressure and volume measurements of air within a sealed syringe in different states of compression. Both qualitative and quantitative tasks for the sealed syringe system were examined. It was found that 34% to 38% of students did not understand the concepts of volume and mass, respectively, of a gas under such circumstances. Performance on an inverse ratio (2:1) task was shown to depend on gender and those students who performed well on the 2:1 inverse ratio task did not necessarily perform well on a different inverse ratio task when an arithmetic averaging principle was present. Tasks which draw upon qualitative knowledge as well as quantitative knowledge have the potential to reduce dependence on algorithms, particularly equation substitution and solution. The implications for instructional design are discussed.Received: 14 April 1993; Revised: 29 June 1994;

  20. The Effect of Isotopic Composition on the Uncertainty of Routine Metal Mass Concentration Measurements in Ambient Air

    PubMed Central

    Brown, Richard J. C.; Goddard, Sharon L.; Brown, Andrew S.; Yardley, Rachel E.

    2008-01-01

    The main sources of uncertainty encountered during the analysis of the mass concentration of metals in ambient air as part of the operation of the UK Heavy Metals Monitoring Network are presented. It is observed that the uncertainty contribution from possible variation in the isotopic composition of the sample depends on the element in question, but can be significant (e.g., for Pb, Cd, and Hg). The working curve method for the ICP-MS analysis of metals in solution, with a low resolution, high throughput instrument measuring at one m/z ratio per element, relies on the relative abundance of the isotopes under consideration being the same in both the sample and the calibration solution. Calculation of the uncertainty in this analysis assumes that the isotopic composition variation within the sample and calibration solution is limited to a defined range. Therefore, in order to confirm the validity of this quantification methodology and its uncertainty budget, the isotopic composition of the calibration standards used for quantification has been determined. The results of this analysis are presented here. PMID:19223968

  1. Total ozone seasonal and interannual variations in the principal air masses of the Northern Hemisphere in 1975-1990

    NASA Technical Reports Server (NTRS)

    Karol, Igor L.; Klyagina, L. P.; Shalamyansky, A. M.; Jagovkina, S. V.

    1994-01-01

    The diurnally mean total ozone X from the Northern Hemisphere ground based 90 stations for 1975-1990 are averaged over the Arctic (bar X (sub A)) Intermediate (bar X (sub I)) and Tropical (bar X (sub T)) air mass areas, divided by the jet stream axes on the isobaric surfaces 300 and 200 mb. The mean square variations of the so averaged X are considerably smaller than of the X, averaged over the corresponding zonal belts. This property allows one to improve considerably the statistical significance of X trends and changes over various time periods, taking into account the time correlation of data for adjacent time intervals. Bar X (sub A), bar X (sub I), and bar X (sub T) trends are estimated over the periods of solar activity rise and fall in its 21st and rise in its 22nd 11 year cycles and over the periods of west and east phases of the known over the periods of west and east phases of the known quasibiennial oscillation (QBO). Solar activity variations affect mostly bar X (sub T), bar X (sub I) trends in summer months, while QBO phases influence the X changes mostly during the cold half year. X are lower in the west QBO phase and their trend is negative during almost all periods considered. The anthropogenic effects on the X is also estimated.

  2. Urban air pollution, poverty, violence and health--Neurological and immunological aspects as mediating factors.

    PubMed

    Kristiansson, Marianne; Sörman, Karolina; Tekwe, Carmen; Calderón-Garcidueñas, Lilian

    2015-07-01

    Rapid rural-urban migration has created overcrowded areas characterized by concentrated poverty and increases in indoor and outdoor air pollutants. These "hotspots" constitute an increased risk of violence and disease outbreaks. We hypothesize that the effects of poverty and associated air pollution-related stress on impaired cognitive skills are mediated by inflammatory cytokines. A research framework is proposed, encompassing (i) an epidemiological investigation of associations between poverty, high concentrations of air pollutants, violence and health, (ii) a longitudinal follow-up of working memory capacities and inflammatory markers, and (iii) intervention programs aiming to strengthen employability and decreased exposures to toxic air pollutants.

  3. Relative Sensitivity Factors for Submicron Secondary Ion Mass Spectrometry with Gallium Primary Ion Beam

    NASA Astrophysics Data System (ADS)

    Satoh, Hitomi; Owari, Masanori; Nihei, Yoshimasa

    1993-08-01

    Relative sensitivity factors (RSFs) of thirteen elements in the oxide glass matrix in secondary ion mass spectrometry (SIMS) excited by a gallium focused ion beam were determined. RSFs were obtained by analyzing powder particles of standard glass samples. Whole volumes of each particles were analyzed in the “shave-off” mode in order to avoid topographic effects. Reproducibility of RSFs was good, and sample-to-sample scattering of values was relatively small. Dependence of RSFs on the first ionization potential was shown to be reasonable. In order to check the validity of the RSFs, coal fly ash particles were analyzed. The results were in reasonable agreement with the data obtained through the bulk chemical analysis.

  4. Charge/mass dynamic structure factors of water and applications to dielectric friction and electroacoustic conversion

    NASA Astrophysics Data System (ADS)

    Sedlmeier, Felix; Shadkhoo, Shahriar; Bruinsma, Robijn; Netz, Roland R.

    2014-02-01

    We determine time correlation functions and dynamic structure factors of the number and charge density of liquid water from molecular dynamics simulations. Using these correlation functions we consider dielectric friction and electro-acoustic coupling effects via linear response theory. From charge-charge correlations, the drag force on a moving point charge is derived and found to be maximal at a velocity of around 300 m/s. Strong deviations in the resulting friction coefficients from approximate theory employing a single Debye relaxation mode are found that are due to non-Debye-like resonances at high frequencies. From charge-mass cross-correlations the ultrasonic vibration potential is derived, which characterizes the conversion of acoustic waves into electric time-varying potentials. Along the dispersion relation for normal sound waves in water, the ultrasonic vibration potential is shown to strongly vary and to increase for larger wavelengths.

  5. Charge/mass dynamic structure factors of water and applications to dielectric friction and electroacoustic conversion.

    PubMed

    Sedlmeier, Felix; Shadkhoo, Shahriar; Bruinsma, Robijn; Netz, Roland R

    2014-02-07

    We determine time correlation functions and dynamic structure factors of the number and charge density of liquid water from molecular dynamics simulations. Using these correlation functions we consider dielectric friction and electro-acoustic coupling effects via linear response theory. From charge-charge correlations, the drag force on a moving point charge is derived and found to be maximal at a velocity of around 300 m/s. Strong deviations in the resulting friction coefficients from approximate theory employing a single Debye relaxation mode are found that are due to non-Debye-like resonances at high frequencies. From charge-mass cross-correlations the ultrasonic vibration potential is derived, which characterizes the conversion of acoustic waves into electric time-varying potentials. Along the dispersion relation for normal sound waves in water, the ultrasonic vibration potential is shown to strongly vary and to increase for larger wavelengths.

  6. Body mass index of married Bangladeshi women: trends and association with socio-demographic factors.

    PubMed

    Hossain, M G; Bharati, P; Aik, Saw; Lestrel, Pete E; Abeer, Almasri; Kamarul, T

    2012-07-01

    Body mass index (BMI) is a good indicator of nutritional status in a population. In underdeveloped countries like Bangladesh, this indicator provides a method that can assist intervention to help eradicate many preventable diseases. This study aimed to report on changes in the BMI of married Bangladeshi women who were born in the past three decades and its association with socio-demographic factors. Data for 10,115 married and currently non-pregnant Bangladeshi women were extracted from the 2007 Bangladesh Demographic and Health Survey (BDHS). The age range of the sample was 15-49 years. The mean BMI was 20.85 ± 3.66 kg/m(2), and a decreasing tendency in BMI was found among birth year cohorts from 1972 to 1992. It was found that the proportion of underweight females has been increasing in those born during the last 20 years of the study period (1972 to 1992). Body mass index increased with increasing age, education level of the woman and her husband, wealth index, age at first marriage and age at first delivery, and decreased with increasing number of ever-born children. Lower BMI was especially pronounced among women who were living in rural areas, non-Muslims, employed women, women not living with their husbands (separated) or those who had delivered at home or non-Caesarean delivery.

  7. Body mass index as a prognostic factor in organophosphate-poisoned patients.

    PubMed

    Lee, Duk Hee; Jung, Koo Young; Choi, Yoon Hee; Cheon, Young Jin

    2014-07-01

    Organophosphate poisoning is a serious clinical entity and considerable morbidity and mortality. Several factors have been identified to predict outcomes of organophosphate poisoning. Organophosphates are lipophilic and therefore predicted to have a large volume of distribution and to rapidly distribute into tissue and fat. Thus, toxic effects of organophosphate would be expected to last longer in obese patients. We investigated the relationship between obesity and clinical course in 112 acute organophosphate-poisoned patients from an initial medical record review of 234 patients. One hundred twenty-two patients were excluded: 6 were children, 14 had an uncertain history of exposure and of uncertain agent, 10 were transferred to another hospital, 67 were discharged from the emergency department because their toxicity was mild, 21 had carbamate poisoning, and 4 did not have height or weight checked. Clinical features, body mass index, Glasgow Coma Scale, laboratory findings, serum cholinesterase activity, electrocardiogram finding, management, and outcomes were examined. The lipid solubility of the implicated organophosphate was characterized by its octanol/water coefficient. Forty of 112 patients were obese. Obese patients who were poisoned by high lipophilicity organophosphate compounds had a need for longer use of mechanical ventilation, intensive care unit care, and total length of admission. Body mass index can provide a guide to physicians in predicting clinical course and management in organophosphate-poisoned patients.

  8. Factors behind change in knowledge after a mass media campaign targeting periodontitis.

    PubMed

    Mårtensson, C; Söderfeldt, B; Andersson, P; Halling, A; Renvert, S

    2006-02-01

    The aim of this study was to investigate changes in knowledge before and after a mass media campaign, in relation to social attributes, care system attributes and oral health aspects. The study was based on a questionnaire in a cohort design, sent out to 900 randomly sampled people aged 50-75 in Sweden. The response rate to the questionnaire before and after the campaign was 70% and 65% respectively. Sixty-four percent answered both questionnaires. Two questions addressed knowledge, while 10 questions aimed to measure social attributes, care system attributes and oral health aspects. Data were analysed for bivariate relations as to change in knowledge and social attributes, care system attributes and oral health aspects. Data were also analysed in multiple regression analysis with knowledge before, knowledge after and knowledge differences as dependent variables. The results showed that there were a number of independent variables with influence on the dependent variables. Of the social attributes, secondary education gave almost 10% (P < 0.001) better knowledge both before and after the campaign. Among care system attributes, high care utilization was related to knowledge both before and after the campaign. The most important factors for knowledge about periodontitis were education, care utilization and perceived importance of oral health. In conclusion, this study demonstrates that mass media might increase knowledge about periodontitis as a health promotion strategy.

  9. Storage Stability of Keratinocyte Growth Factor-2 in Lyophilized Formulations: Effects of Formulation Physical Properties and Protein Fraction at the Solid-Air Interface

    PubMed Central

    Devineni, Dilip; Gonschorek, Christoph; Cicerone, Marcus T; Xu, Yemin; Carpenter, John F.; Randolph, Theodore W.

    2014-01-01

    Lyophilized formulations of keratinocyte growth factor-2 (KGF-2) were prepared with a range of disaccharide (sucrose or trehalose) and hydroxyethyl starch (HES) mass ratios. Protein degradation was assessed as a function of time of storage of the dried formulations at 40, 50 and 60 °C. Lyophilized and stored samples were rehydrated, and protein degradation was quantified by measuring loss of monomeric protein with size exclusion chromatography and by determining chemical degradation in the soluble fraction with reverse-phase chromatography. The secondary structure of the protein in the lyophilized formulations was studied with infrared spectroscopy. The magnitudes of degradation were compared the key physical properties of the formulations including retention of protein native secondary structure, glass transition temperature (Tg), inverse mean square displacements −1 for hydrogen atoms (fast β relaxation), and the relaxation time τβ, which correlates with relaxation due to fast Johari-Goldstein motions in the glass[1]. In addition, specific surface areas of the lyophilized formulations were determined by Brunauer-Emmet-Teller analysis of krypton adsorption isotherms and used to estimate the fraction of the KGF-2 molecules residing at the solid-air interface. KGF-2 degradation rates were highest in formulations wherein the protein’s structure was most perturbed, and wherein β relaxations were fastest, but the dominant factor governing KGF-2 degradation in freeze-dried formulations was the fraction of the protein found at the glass solid-air interface. PMID:24859390

  10. Air pollution, a rising environmental risk factor for cognition, neuroinflammation and neurodegeneration: The clinical impact on children and beyond.

    PubMed

    Calderón-Garcidueñas, L; Leray, E; Heydarpour, P; Torres-Jardón, R; Reis, J

    2016-01-01

    Air pollution (indoors and outdoors) is a major issue in public health as epidemiological studies have highlighted its numerous detrimental health consequences (notably, respiratory and cardiovascular pathological conditions). Over the past 15 years, air pollution has also been considered a potent environmental risk factor for neurological diseases and neuropathology. This review examines the impact of air pollution on children's brain development and the clinical, cognitive, brain structural and metabolic consequences. Long-term potential consequences for adults' brains and the effects on multiple sclerosis (MS) are also discussed. One challenge is to assess the effects of lifetime exposures to outdoor and indoor environmental pollutants, including occupational exposures: how much, for how long and what type. Diffuse neuroinflammation, damage to the neurovascular unit, and the production of autoantibodies to neural and tight-junction proteins are worrisome findings in children chronically exposed to concentrations above the current standards for ozone and fine particulate matter (PM2.5), and may constitute significant risk factors for the development of Alzheimer's disease later in life. Finally, data supporting the role of air pollution as a risk factor for MS are reviewed, focusing on the effects of PM10 and nitrogen oxides.

  11. Size-Segregated Aerosol Composition and Mass Loading of Atmospheric Particles as Part of the Pacific Northwest 2001(PNW2001) Air Quality Study In Puget Sound

    NASA Astrophysics Data System (ADS)

    Disselkamp, R. S.; Barrie, L. A.; Shutthanadan, S.; Cliff, S.; Cahill, T.

    2001-12-01

    In mid-August, 2001, an aircraft-based air-quality study was performed in the Puget Sound, WA, area entitled PNW2001 (http://www.pnl.gov/pnw2001). The objectives of this field campaign were the following: 1. reveal information about the 3-dimensional distribution of ozone, its gaseous precursors and fine particulate matter during weather conditions favoring air pollution; 2. derive information about the accuracy of urban and biogenic emissions inventories that are used to drive the air quality forecast models; and 3. examine the accuracy of modeled ozone concentration with that observed. In support of these efforts, we collected time-averaged ( { ~}10 minute averages), size-segregated, aerosol composition and mass-loading information using ex post facto analysis techniques of synchrotron x-ray fluorescence (s-XRF), proton induced x-ray emissions(PIXE), proton elastic scattering (PESA), and scanning transmission ion microscopy (STIM). This is the first time these analysis techniques have been used together on samples collected from aircraft using an optimized 3-stage rotating drum impactor. In our presentation, we will discuss the aerosol components in three aerosol size fractions as identified by statistical analysis of multielemental data (including total mass, H, Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Pb) and relate variations in these components to physical aerosol properties, other gaseous trace constituents and to air mass origin.

  12. Measurements of δ13C in CH4 and using particle dispersion modeling to characterize sources of Arctic methane within an air mass

    NASA Astrophysics Data System (ADS)

    France, J. L.; Cain, M.; Fisher, R. E.; Lowry, D.; Allen, G.; O'Shea, S. J.; Illingworth, S.; Pyle, J.; Warwick, N.; Jones, B. T.; Gallagher, M. W.; Bower, K.; Le Breton, M.; Percival, C.; Muller, J.; Welpott, A.; Bauguitte, S.; George, C.; Hayman, G. D.; Manning, A. J.; Myhre, C. Lund; Lanoisellé, M.; Nisbet, E. G.

    2016-12-01

    A stratified air mass enriched in methane (CH4) was sampled at 600 m to 2000 m altitude, between the north coast of Norway and Svalbard as part of the Methane in the Arctic: Measurements and Modelling campaign on board the UK's BAe-146-301 Atmospheric Research Aircraft. The approach used here, which combines interpretation of multiple tracers with transport modeling, enables better understanding of the emission sources that contribute to the background mixing ratios of CH4 in the Arctic. Importantly, it allows constraints to be placed on the location and isotopic bulk signature of the emission source(s). Measurements of δ13C in CH4 in whole air samples taken while traversing the air mass identified that the source(s) had a strongly depleted bulk δ13C CH4 isotopic signature of -70 (±2.1)‰. Combined Numerical Atmospheric-dispersion Modeling Environment and inventory analysis indicates that the air mass was recently in the planetary boundary layer over northwest Russia and the Barents Sea, with the likely dominant source of methane being from wetlands in that region.

  13. Formaldehyde quantitation in air samples by thiazolidine derivatization: Factors affecting analysis

    SciTech Connect

    Yasuhara, A.; Shibamoto, T. )

    1989-11-01

    A new method for the determination of trace levels of formaldehyde in air was developed and validated. The method is based on the reaction of formaldehyde with cysteamine to form thiazolidine. Air samples containing trace levels of formaldehyde were prepared from paraformaldehyde. The percent yield of formaldehyde from paraformaldehyde was 85.1 +/- 1.14%. Air samples were bubbled into an aqueous cysteamine trap. Thiazolidine formed from formaldehyde and cysteamine in the trap was determined by gas chromatography with a fused silica capillary column and a nitrogen-phosphorus detector (NPD). The lowest detection level for thiazolidine was 17.2 pg, equivalent to 5.80 pg formaldehyde. The recovery efficiency of trace gas phase formaldehyde in air was greater than 90%. Formaldehyde levels in ambient laboratory air were 48.9-56.2 ppb (v/v).

  14. The quantification of carbon dioxide in humid air and exhaled breath by selected ion flow tube mass spectrometry.

    PubMed

    Smith, David; Pysanenko, Andriy; Spanel, Patrik

    2009-05-01

    The reactions of carbon dioxide, CO(2), with the precursor ions used for selected ion flow tube mass spectrometry, SIFT-MS, analyses, viz. H(3)O(+), NO(+) and O(2) (+), are so slow that the presence of CO(2) in exhaled breath has, until recently, not had to be accounted for in SIFT-MS analyses of breath. This has, however, to be accounted for in the analysis of acetaldehyde in breath, because an overlap occurs of the monohydrate of protonated acetaldehyde and the weakly bound adduct ion, H(3)O(+)CO(2), formed by the slow association reaction of the precursor ion H(3)O(+) with CO(2) molecules. The understanding of the kinetics of formation and the loss rates of the relevant ions gained from experimentation using the new generation of more sensitive SIFT-MS instruments now allows accurate quantification of CO(2) in breath using the level of the H(3)O(+)CO(2) adduct ion. However, this is complicated by the rapid reaction of H(3)O(+)CO(2) with water vapour molecules, H(2)O, that are in abundance in exhaled breath. Thus, a study has been carried out of the formation of this adduct ion by the slow three-body association reaction of H(3)O(+) with CO(2) and its rapid loss in the two-body reaction with H(2)O molecules. It is seen that the signal level of the H(3)O(+)CO(2) adduct ion is sensitively dependent on the humidity (H(2)O concentration) of the sample to be analysed and a functional form of this dependence has been obtained. This has resulted in an appropriate extension of the SIFT-MS software and kinetics library that allows accurate measurement of CO(2) levels in air samples, ranging from very low percentage levels (0.03% typical of tropospheric air) to the 6% level that is about the upper limit in exhaled breath. Thus, the level of CO(2) can be traced through single time exhalation cycles along with that of water vapour, also close to the 6% level, and of trace gas metabolites that are present at only a few parts-per-billion. This has added a further dimension to

  15. Maternal insulin-like growth factor binding protein-1, body mass index, and fetal growth

    PubMed Central

    Holmes, R.; Holly, J; Soothill, P.

    2000-01-01

    AIM—To examine the hypothesis that the maternal insulin-like growth factor system may constrain fetal growth.
METHODS—A prospective observational study of maternal serum insulin-like growth factor binding protein-1 (IGFBP-1) and fetal growth was undertaken in neonates with birthweights below the 5th centile. They had been classified either as having fetal growth restriction (FGR) due to placental dysfunction (increased umbilical artery Doppler pulsatility index (PI); n = 25) or as being small for gestational age (SGA; normal umbilical artery PI, growth velocity and amniotic fluid; n = 27). Eighty nine controls had normal birthweights (5th-95th centile), umbilical artery PI, growth velocity, and amniotic fluid. IGFBP-1 was measured by radioimmunoassay.
RESULTS—Among the controls, there was no significant correlation between IGFBP-1 and birthweight after allowing for body mass index (BMI). Maternal BMI was high in FGR and after adjusting for this, IGFBP-1 was increased (109 ng/ml) compared with SGA babies (69ng/ml) and controls (57 ng/ml) and correlated with the umbilical artery PI.
CONCLUSIONS—Maternal IGFBP-1 is probably not part of normal placental function. Its increase in FGR could be the cause or consequence of impaired placental perfusion, but high IGFBP-1 concentrations might further reduce the availability of maternal IGF-I to the placenta. This could worsen placental function and so adversely affect fetal growth.
 PMID:10685983

  16. Characterization of ion processes in a GC/DMS air quality monitor by integration of the instrument to a mass spectrometer.

    PubMed

    Limero, T F; Nazarov, E G; Menlyadiev, M; Eiceman, G A

    2015-02-07

    The air quality monitor (AQM), which included a portable gas chromatograph (GC) and a detector was interfaced to a mass spectrometer (MS) by introducing flow from the GC detector to the atmospheric pressure ion source of the MS. This small GC system, with a gas recirculation loop for carrier and detector make-up gases, comprised an inlet to preconcentrate volatile organic compounds (VOCs) in air, a thermal desorber before the GC column, a differential mobility spectrometer (DMS), and another DMS as an atmospheric pressure ionization source for the MS. Return flow to the internally recirculated air system of the AQM's DMS was replenished using purified air. Although ions and unreacted neutral vapors flowed from the detector through Viton® tubing into the source of the MS, ions were not detected in the MS without the auxillary ion source, (63)Ni as in the mobility detector. The GC-DMS-MS instrument provided a 3-D measurement platform (GC, DMS, and MS analysis) to explore the gas composition inside the GC-DMS recirculation loop and provide DMS-MS measurement of the components of a complex VOC mixture with performance significantly enhanced by mass-analysis, either with mass spectral scans or with an extracted ion chromatogram. This combination of a mobility spectrometer and a mass spectrometer was possible as vapors and ions are carried together through the DMS analyzer, thereby preserving the chromatographic separation efficiency. The critical benefit of this instrument concept is that all flows in and through the thoroughly integrated GC-DMS analyzer are kept intact allowing a full measure of the ion and vapor composition in the complete system. Performance has been evaluated using a synthetic air sample and a sample of airborne vapors in a laboratory. Capabilities and performance values are described using results from AQM-MS analysis of purified air, ambient air from a research laboratory in a chemistry building, and a sample of synthetic air of known composition

  17. Quantitative comparison of a flared and a standard heated metal capillary inlet with a voltage-assisted air amplifier on an electrospray ionization linear ion trap mass spectrometer.

    PubMed

    Dixon, R Brent; Muddiman, David C

    2007-01-01

    The performance characteristics (i.e., ion abundance and electrospray ion current) of a flared and blunt-ended heated metal capillary were evaluated with a voltage-assisted air amplifier on a linear ion trap mass spectrometer (LTQ-MS). The results demonstrated that a standard capillary afforded higher ion abundance than a flared capillary, thus further work is necessary to investigate conditions for which significant benefits with the flared capillary will be observed. The compatibility of a voltage-assisted air amplifier is explored for both types of capillaries and in all cases resulted in improved ion abundance and spray current.

  18. Relationship between the merit factor of thermoelectric materials and the air conditioning unit of urban electric cars

    NASA Astrophysics Data System (ADS)

    Buffet, Jean

    1994-08-01

    The main benefit of electric cars is to reduce air pollution in cities that is thus desirable to equip them with non polluting air conditioning units and this rules out frigorific compressors operating with CFC. The planned replacement of CFC by HFC is at best an interim solution. The best solution is certainly to use thermoelectric air conditioning units, which are inherently pollution-free. However, these have a fairly low COPF when compared to traditional compressor units. We study the relationship between the cooling of the interior of urban electric cars and the merit factor of the thermoelectric material in their Peltier unit. This should help provide concrete target properties of future T E materials.

  19. Measurement and analysis of aerosol and black carbon in the southwestern United States and Panama and their dependence on air mass origin

    NASA Astrophysics Data System (ADS)

    Junker, C.; Sheahan, J. N.; Jennings, S. G.; O'Brien, P.; Hinds, B. D.; Martinez-Twary, E.; Hansen, A. D. A.; White, C.; Garvey, D. M.; Pinnick, R. G.

    2004-07-01

    Total aerosol mass loading, aerosol absorption, and black carbon (BC) content were determined from aerosol collected on 598 quartz fiber filters at a remote, semiarid site near Orogrande, New Mexico from December 1989 to October 1995. Aerosol mass was determined by weighing filters before and after exposure, and aerosol absorption was determined by measuring the visible light transmitted through loaded filter samples and converting these measurements to aerosol absorption. BC content was determined by measuring visible light transmitted through filter samples before and after firing and converting the absorption to BC mass, assuming a BC absorption cross section of 19 m2/g in the fiber filter medium. Two analyses were then performed on each of the logged variables: an autoregressive integrating moving average (ARIMA) analysis and a decomposition analysis using an autoregressive model to accommodate first-order autocorrelation. The two analyses reveal that BC mass has no statistically significant seasonal dependence at the 5% level of significance but only random fluctuations varying around an average annual value that has a long-term decreasing trend (from 0.16 to 0.11 μg/m3 during 1990-1995). Aerosol absorption, which is dominated by BC, also displays random fluctuations about an average value, and decreases from 1.9 Mm-1 to 1.3 Mm-1 during the same period. Unlike BC, aerosol mass at the Orogrande site displays distinctly different character. The analyses reveal a pronounced seasonal dependence, but no long-term trend for aerosol mass. The seasonal indices resulting from the autoregression analysis have a minimum in January (-0.78) and maximum in June (+0.58). The geometric mean value over the 1990-1995 period for aerosol mass is 16.0 μg/m3. Since BC aerosol at the Orogrande site is a product of long-range atmospheric transport, a back trajectory analysis of air masses was conducted. Back trajectory analyses indicate that air masses traversing high population

  20. Patient and procedural factors associated with an increased risk of harm or death in the first 4,000 incidents reported to webAIRS.

    PubMed

    Gibbs, N M; Culwick, M D; Merry, A F

    2017-03-01

    This report describes an analysis of patient and procedural factors associated with a higher proportion of harm or death versus no harm in the first 4,000 incidents reported to webAIRS. The report is supplementary to a previous cross-sectional report on the first 4,000 incidents reported to webAIRS. The aim of this analysis was to identify potential patient or procedural factors that are more common in incidents resulting in harm or death than in incidents with more benign outcomes. There was a >50% higher proportion of harm (versus no harm) for incidents in which the patient's body mass index (BMI) was <18.5 kg/m2, for incidents in post-anaesthesia care units and non-theatre procedural areas, and for incidents under the main category of cardiovascular or neurological. The proportion of incidents associated with death was also higher (risk ratio >1.5) for BMI <18.5 kg/m2, incidents in non-theatre procedural areas, and incidents under the main category of cardiovascular or neurological. In addition, the proportion of incidents associated with death was higher for incidents in which the patient's age was >80 years, the American Society of Anesthesiologists physical status was 4 or 5, incidents involving non-elective procedures, and incidents occurring after hours (1800 to 0800 hours). When faced with incidents with these potential risk factors, anaesthetists should consider earlier interventions and request assistance at an earlier stage. Educational strategies on incident prevention and management should place even further emphasis on scenarios involving these factors.

  1. Interlaboratory evaluation of trace element determination in workplace air filter samples by inductively coupled plasma mass spectrometry†‡

    PubMed Central

    Shulman, Stanley A.; Brisson, Michael J.; Howe, Alan M.

    2015-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is becoming more widely used for trace elemental analysis in the occupational hygiene field, and consequently new ICP-MS international standard procedures have been promulgated by ASTM International and ISO. However, there is a dearth of interlaboratory performance data for this analytical methodology. In an effort to fill this data void, an interlaboratory evaluation of ICP-MS for determining trace elements in workplace air samples was conducted, towards fulfillment of method validation requirements for international voluntary consensus standard test methods. The study was performed in accordance with applicable statistical procedures for investigating interlaboratory precision. The evaluation was carried out using certified 37-mm diameter mixed-cellulose ester (MCE) filters that were fortified with 21 elements of concern in occupational hygiene. Elements were spiked at levels ranging from 0.025 to 10 μg filter−1, with three different filter loadings denoted “Low”, “Medium” and “High”. Participating laboratories were recruited from a pool of over fifty invitees; ultimately twenty laboratories from Europe, North America and Asia submitted results. Triplicates of each certified filter with elemental contents at three different levels, plus media blanks spiked with reagent, were conveyed to each volunteer laboratory. Each participant was also provided a copy of the test method which each participant was asked to follow; spiking levels were unknown to the participants. The laboratories were requested to prepare the filters by one of three sample preparation procedures, i.e., hotplate digestion, microwave digestion or hot block extraction, which were described in the test method. Participants were then asked to analyze aliquots of the prepared samples by ICP-MS, and to report their data in units of μg filter−1. Most interlaboratory precision estimates were acceptable for medium- and high

  2. sup 222 Rn, sup 222 Rn progeny and sup 220 Rn progeny as atmospheric tracers of air masses at the Mauno Loa Observatory

    SciTech Connect

    Hutter, A.R.; George, A.C.; Maiello, M.L.; Fisenne, I.M.; Larsen, R.J.; Beck, H.L.; Wilson, F.C.

    1990-03-01

    {sup 222}Rn, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations in air were measured at the Mauna Loa Observatory (MLO) in Hawaii during March 1989 in order to investigate the feasibility of using them as atmospheric tracers to help determine local air mass flow patterns. Charcoal traps, cooled to dry ice temperatures, were used to collect {sup 222}Rn, which was subsequently measured in pulse ionization chambers at the Environmental Measurements Laboratory (EML). {sup 222}Rn progeny and {sup 220}Rn progeny for 37 samples were measured at the Observatory by sampling high volumes of air through filters, which were counted for up to 11 h in alpha scintillation counters. Individual progeny concentrations were calculated using both least squares and maximum likelihood techniques. In general, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations were low when free tropospheric air was present (downslope and tradewind conditions), and consistently higher when surface air from the island broke through the trade wind inversion layer (upslope conditions). The data suggest that {sup 222}Rn, {sup 222}Rn progeny, or {sup 220}Rn progeny monitoring may provide new and useful information to help indicate the different air flow patterns present at MLO. 17 refs., 5 figs., 2 tabs.

  3. Mobile selected ion flow tube mass spectrometry (SIFT-MS) devices and their use for pollution exposure monitoring in breath and ambient air-pilot study.

    PubMed

    Storer, Malina; Salmond, Jennifer; Dirks, Kim N; Kingham, Simon; Epton, Michael

    2014-09-01

    Studies of health effects of air pollution exposure are limited by inability to accurately determine dose and exposure of air pollution in field trials. We explored the feasibility of using a mobile selected ion flow tube mass spectrometry (SIFT-MS) device, housed in a van, to determine ambient air and breath levels of benzene, xylene and toluene following exercise in areas of high motor vehicle traffic. The breath toluene, xylene and benzene concentration of healthy subjects were measured before and after exercising close to a busy road. The concentration of the volatile organic compounds (VOCs), in ambient air were also analysed in real time. Exercise close to traffic pollution is associated with a two-fold increase in breath VOCs (benzene, xylene and toluene) with levels returning to baseline within 20 min. This effect is not seen when exercising away from traffic pollution sources. Situating the testing device 50 m from the road reduced any confounding due to VOCs in the inspired air prior to the breath testing manoeuvre itself. Real-time field testing for air pollution exposure is possible using a mobile SIFT-MS device. This device is suitable for exploring exposure and dose relationships in a number of large scale field test scenarios.

  4. Measurement of Pressure Dependent Fluorescence Yield of Air: Calibration Factor for UHECR Detectors

    SciTech Connect

    Belz, J.W.; Burt, G.W.; Cao, Z.; Chang, F.Y.; Chen, C.C.; Chen, C.W.; Chen, P.; Field, C.; Findlay, J.; Huntemeyer, Petra; Huang, M.A.; Hwang, W.-Y.P.; Iverson, R.; Jones, B.F.; Jui, C.C.H.; Kirn, M.; Lin, G.-L.; Loh, E.C.; Maestas, M.M.; Manago, N.; Martens, K.; /Montana U. /Utah U. /Taiwan, Natl. Taiwan U. /SLAC /Rutgers U., Piscataway

    2005-07-06

    In a test experiment at the Final Focus Test Beam of the Stanford Linear Accelerator Center, the fluorescence yield of 28.5 GeV electrons in air and nitrogen was measured. The measured photon yields between 300 and 400 nm at 1 atm and 29 C are Y(760 Torr){sup air} = 4.42 {+-} 0.73 and Y(760 Torr){sup N{sub 2}} = 29.2 {+-} 4.8 photons per electron per meter. Assuming that the fluorescence yield is proportional to the energy deposition of a charged particle traveling through air, good agreement with measurements at lower particle energies is observed.

  5. Sparkover performance and gap factors of air gaps below 1 meter: Analysis of published data. Final report

    SciTech Connect

    Gela, G.

    1998-03-01

    This report is an account of a literature search on sparkover performance of various air gaps shorter than 1 meter. The report is a part of the Live Working 2000 project. The objective of the literature search was to locate and analyze published data on sparkover performance of air gaps below 1 meter, with special emphasis on live working. Published data dating back to 1930`s are analyzed for a variety of air gaps: rod-to-plane; rod-to-rod; sphere-to-plane; bundle-to-plane; hoop-to-plane, conductor-to-rod; and worker-to-tower. Data for all voltage types, and both polarities (where applicable) are analyzed: power frequency alternating current; direct current; lightning; fast front impulse; and switching impulse. As is the case for longer air gaps and higher voltages, several accurate empirical formulae for calculation of the sparkover voltage have been developed, and are analyzed. Also, the rod-to-plane air gap is used in this report as the reference gap for calculation of gap factors.

  6. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations.

    PubMed

    Fernández-Somoano, Ana; Llop, Sabrina; Aguilera, Inmaculada; Tamayo-Uria, Ibon; Martínez, María Dolores; Foraster, Maria; Ballester, Ferran; Tardón, Adonina

    2015-06-18

    This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (none) to 10 (strong and unbearable); a level of 8 to 10 was considered high. The reported prevalence of high annoyance levels from air pollution was 11.2% and 15.0% from noise; the two variables were moderately correlated (0.606). Significant correlations between NO2 and annoyance from air pollution (0.154) and that from noise (0.181) were observed. Annoyance owing to noise and air pollution had a low prevalence in our Spanish population compared with other European populations. Both factors were associated with proximity to traffic. In multivariate models, annoyance from air pollution was related to NO2, building age, and country of birth; annoyance from noise was only related to the first two. The health burden of these exposures can be increased by stress caused by the perception of pollution sources.

  7. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations

    PubMed Central

    Fernández-Somoano, Ana; Llop, Sabrina; Aguilera, Inmaculada; Tamayo-Uria, Ibon; Martínez, María Dolores; Foraster, Maria; Ballester, Ferran; Tardón, Adonina

    2015-01-01

    This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (none) to 10 (strong and unbearable); a level of 8 to 10 was considered high. The reported prevalence of high annoyance levels from air pollution was 11.2% and 15.0% from noise; the two variables were moderately correlated (0.606). Significant correlations between NO2 and annoyance from air pollution (0.154) and that from noise (0.181) were observed. Annoyance owing to noise and air pollution had a low prevalence in our Spanish population compared with other European populations. Both factors were associated with proximity to traffic. In multivariate models, annoyance from air pollution was related to NO2, building age, and country of birth; annoyance from noise was only related to the first two. The health burden of these exposures can be increased by stress caused by the perception of pollution sources. PMID:26095869

  8. Characteristics of particle number and mass emissions during heavy-duty diesel truck parked active DPF regeneration in an ambient air dilution tunnel

    NASA Astrophysics Data System (ADS)

    Yoon, Seungju; Quiros, David C.; Dwyer, Harry A.; Collins, John F.; Burnitzki, Mark; Chernich, Donald; Herner, Jorn D.

    2015-12-01

    Diesel particle number and mass emissions were measured during parked active regeneration of diesel particulate filters (DPF) in two heavy-duty diesel trucks: one equipped with a DPF and one equipped with a DPF + SCR (selective catalytic reduction), and compliant with the 2007 and 2010 emission standards, respectively. The emission measurements were conducted using an ambient air dilution tunnel. During parked active regeneration, particulate matter (PM) mass emissions measured from a 2007 technology truck were significantly higher than the emissions from a 2010 technology truck. Particle number emissions from both trucks were dominated by nucleation mode particles having a diameter less than 50 nm; nucleation mode particles were orders of magnitude higher than accumulation mode particles having a diameter greater than 50 nm. Accumulation mode particles contributed 77.8 %-95.8 % of the 2007 truck PM mass, but only 7.3 %-28.2 % of the 2010 truck PM mass.

  9. Prediction of Mass Spectral Response Factors from Predicted Chemometric Data for Druglike Molecules

    NASA Astrophysics Data System (ADS)

    Cramer, Christopher J.; Johnson, Joshua L.; Kamel, Amin M.

    2017-02-01

    A method is developed for the prediction of mass spectral ion counts of drug-like molecules using in silico calculated chemometric data. Various chemometric data, including polar and molecular surface areas, aqueous solvation free energies, and gas-phase and aqueous proton affinities were computed, and a statistically significant relationship between measured mass spectral ion counts and the combination of aqueous proton affinity and total molecular surface area was identified. In particular, through multilinear regression of ion counts on predicted chemometric data, we find that log10(MS ion counts) = -4.824 + c 1•PA + c 2•SA, where PA is the aqueous proton affinity of the molecule computed at the SMD(aq)/M06-L/MIDI!//M06-L/MIDI! level of electronic structure theory, SA is the total surface area of the molecule in its conjugate base form, and c 1 and c 2 have values of -3.912 × 10-2 mol kcal-1 and 3.682 × 10-3 Å-2. On a 66-molecule training set, this regression exhibits a multiple R value of 0.791 with p values for the intercept, c 1, and c 2 of 1.4 × 10-3, 4.3 × 10-10, and 2.5 × 10-6, respectively. Application of this regression to an 11-molecule test set provides a good correlation of prediction with experiment ( R = 0.905) albeit with a systematic underestimation of about 0.2 log units. This method may prove useful for semiquantitative analysis of drug metabolites for which MS response factors or authentic standards are not readily available.

  10. Factors controlling precision and accuracy in isotope-ratio-monitoring mass spectrometry

    NASA Technical Reports Server (NTRS)

    Merritt, D. A.; Hayes, J. M.

    1994-01-01

    The performance of systems in which picomole quantities of sample are mixed with a carrier gas and passed through an isotope-ratio mass spectrometer system was examined experimentally and theoretically. Two different mass spectrometers were used, both having electron-impact ion sources and Faraday cup collector systems. One had an accelerating potential of 10kV and accepted 0.2 mL of He/min, producing, under those conditions, a maximum efficiency of 1 CO2 molecular ion collected per 700 molecules introduced. Comparable figures for the second instrument were 3 kV, 0.5 mL of He/min, and 14000 molecules/ion. Signal pathways were adjusted so that response times were <200 ms. Sample-related ion currents appeared as peaks with widths of 3-30 s. Isotope ratios were determined by comparison to signals produced by standard gases. In spite of rapid variations in signals, observed levels of performance were within a factor of 2 of shot-noise limits. For the 10-kV instrument, sample requirements for standard deviations of 0.1 and 0.5% were 45 and 1.7 pmol, respectively. Comparable requirements for the 3-kV instrument were 900 and 36 pmol. Drifts in instrumental characteristics were adequately neutralized when standards were observed at 20-min intervals. For the 10-kV instrument, computed isotopic compositions were independent of sample size and signal strength over the ranges examined. Nonlinearities of <0.04%/V were observed for the 3-kV system. Procedures for observation and subtraction of background ion currents were examined experimentally and theoretically. For sample/ background ratios varying from >10 to 0.3, precision is expected and observed to decrease approximately 2-fold and to depend only weakly on the precision with which background ion currents have been measured.

  11. Heat transfer and friction factor correlations for a solar air heater duct roughened artificially with multiple v-ribs

    SciTech Connect

    Hans, V.S.; Saini, R.P.; Saini, J.S.

    2010-06-15

    The use of artificial roughness on the underside of the absorber plate is an effective and economic way to improve the thermal performance of a solar air heater. Several experimental investigations, involving different types of roughness elements, have been carried out to improve the heat transfer from the absorber plate to air flowing in solar air heaters. This paper presents an experimental investigation carried out to study the effect of multiple v-rib roughness on heat transfer coefficient and friction factor in an artificially roughened solar air heater duct. The experiment encompassed Reynolds number (Re) from 2000 to 20000, relative roughness height (e/D) values of 0.019-0.043, relative roughness pitch (P/e) range of 6-12, angle of attack ({alpha}) range of 30-75 and relative roughness width (W/w) range of 1-10. Extensive experimentation has been conducted to collect data on heat transfer and fluid flow characteristics of a rectangular duct roughened with multiple v-ribs. Using these experimental data, correlations for Nusselt number and friction factor in terms of roughness geometry and flow parameters have been developed. (author)

  12. Risk Factors for Incident Postdeployment Mental Health Conditions Among U.S. Air Force Medical Service Personnel.

    PubMed

    Maupin, Genny M; Tvaryanas, Anthony P; White, Edward D; Lysfjord, Heather J

    2017-03-01

    The prevalence of postdeployment mental health (PDMH) conditions in military health care personnel appears to be on par with that of other military personnel. However, there is no comprehensive analysis of incident PDMH conditions within the overall population of U.S. Air Force Medical Service personnel. This study explored the epidemiology of incident PDMH conditions among Air Force Medical Service personnel returning from deployment. A cohort survival analysis was conducted of 24,409 subjects without preexisting mental health conditions and at least one deployment during 2003-2013. Electronic health record data were used to ascertain the diagnosis of a PDMH condition. The primary outcome measure was an incident PDMH condition defined as a mental health diagnosis on at least two separate clinical encounters. The incidence of PDMH conditions was 59.74 per 1,000 person-years. Adjustment, anxiety, mood, sleep, and post-traumatic stress disorders accounted for 78% diagnoses. Protective factors included officer, surgeon, specific enlisted career fields, Air National Guard or Air Force Reserve, and multiple deployments. Risk factors included nurse, other specific enlisted career fields, female, and unmarried with dependents. Most subjects (73%) were diagnosed within the standard 30-month surveillance time period; median time to diagnosis was 13 months.

  13. Air pollution, PM2.5 composition, source factors, and respiratory symptoms in asthmatic and nonasthmatic children in Santiago, Chile.

    PubMed

    Prieto-Parra, Laura; Yohannessen, Karla; Brea, Cecilia; Vidal, Daniella; Ubilla, Carlos A; Ruiz-Rudolph, Pablo

    2017-04-01

    The objective of this study was to determine the association of respiratory symptoms and medication use and exposure to various air pollutants, PM2.5 components, and source factors in a panel of asthmatic and nonasthmatic children in Santiago, Chile. To this end, 174 children (90 asthmatics and 84 nonasthmatics) were followed throughout the winter months of 2010 and 2011. During the study period, children filled out daily diaries to record respiratory symptoms and medication use. Air pollution data were obtained from government central site measurements and a PM2.5 characterization campaign. PM2.5 source factors were obtained using positive matrix factorization (PMF). Associations of symptoms and exposure to pollutants and source-factor daily scores were modeled separately for asthmatic and nonasthmatic children using mixed logistic regression models with random intercepts, controlling for weather, day of the week, year, and viral outbreaks. Overall, high concentrations of air pollutants and PM2.5 components were observed. Six source factors were identified by PMF (motor vehicles, marine aerosol, copper smelter, secondary sulfates, wood burning, and soil dust). Overall, single pollutant models showed significant and strong associations between 7-day exposures for several criteria pollutants (PM2.5, NO2, O3), PM2.5 components (OC, K, S, Se, V), and source factors (secondary sulfate) and coughing, wheezing and three other respiratory symptoms in both in asthmatic and nonasthmatic children. No associations were found for use of rescue inhalers in asthmatics. Two-pollutant models showed that several associations remained significant after including PM2.5, and other criteria pollutants, in the models, particularly components and source factors associated with industrial sources. In conclusion, exposure to air pollutants, especially PM2.5, NO2, and O3, were found to exacerbate respiratory symptoms in both asthmatic and nonasthmatic children. Some of the results suggest

  14. COPPER-DEPENDENT INFLAMMATION AND NUCLEAR FACTOR-KB ACTIVATION BY PARTICULATE AIR POLLUTION

    EPA Science Inventory

    Particulate air pollution causes increased cardiopulmonary morbidity and mortality, but the chemical determinants responsible for its biologic effects are not understood. We studied the effect of total suspended particulates collected in Provo, Utah, an area where an increase in ...

  15. Relationship of body mass index and other life style factors with hypertension in adolescents

    PubMed Central

    Goel, Manjusha; Pal, Pankaj; Agrawal, Amit; Ashok, Chandrasekaran

    2016-01-01

    Background: Over the past two decades, it has been observed that hypertension shows an increasing trend in children and adolescents. Various factors are contributing to this upward trend, and they primarily include changes in lifestyle and dietary habits. Objectives: The aim of this study was to evaluate the prevalence of hypertension in school going adolescent children and to study the associated risk factors. Materials and Methods: This prospective cross-sectional observational study was conducted over a period of one year on apparently healthy adolescents of randomly selected urban schools of Bhopal district of Madhya Pradesh, Central India. A pretested and prevalidated questionnaire was used to collect the details including present or past history of illness, family history of hypertension, socioeconomic status, and sleep pattern and birth weight of the children. This was followed by anthropometric and blood pressure (BP) measurements and thorough systemic examination. Results: Out of 1221 children recruited in the study, 618 were boys, and 603 were girls. 22.7%, body mass index (BMI) of majority (85%) of the students was between 5th and 84th percentile, 5.65% were obese (BMI ≥95th) and 9.18% children were overweight (85th-95th percentile). Systolic and diastolic hypertension (BP >95th percentile) was seen in 61 (4.1%) and 48 (3.9%) participants, respectively. Both systolic and diastolic hypertension was seen in 30 (2.45%) participants. Systolic and diastolic prehypertension (BP 90th to <95th percentile) was seen in 88 (7.3%) and 68 (5.6%) participants, respectively. A highly significant association (P < 0.01) of sex, BMI, systolic BP, family history of hypertension, and birth weight with diastolic BP was seen. Conclusion: There is a significant positive correlation of BMI with both systolic and diastolic BP. The family history of hypertension appears to be an important risk factor for the increase in both systolic and diastolic BP. Low birth weight and male

  16. Characterizing the chemical evolution of air masses via multi-platform measurements of volatile organic compounds (VOCs) during CalNEX: Composition, OH reactivity, and potential SOA formation

    NASA Astrophysics Data System (ADS)

    Gilman, J. B.; Kuster, W. C.; Bon, D.; Warneke, C.; Lerner, B. M.; Williams, E. J.; Holloway, J. S.; Pollack, I. B.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Herndon, S. C.; Zahniser, M. S.; Vlasenko, A. L.; Li, S.; Alvarez, S. L.; Rappenglueck, B.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; De Gouw, J. A.

    2011-12-01

    Volatile organic compounds (VOCs) are critical components in the photochemical production of ozone (O3) and secondary organic aerosol (SOA). During the CalNex 2010 field campaign, an extensive set of VOCs were measured at the Pasadena ground site, and aboard the NOAA WP-3D aircraft and the WHOI Research Vessel Atlantis. The measurements from each platform provide a unique perspective into the emissions, transport, and atmospheric processing of VOCs within the South Coast Air Basin (SoCAB). The observed enhancement ratios of the hydrocarbons measured on all three platforms are in good agreement and are generally well correlated with carbon monoxide (CO), indicating the prevalence of on-road VOC emission sources throughout the SoCAB. Offshore measurements aboard the ship and aircraft are used to characterize the air mass composition as a function of the land/sea-breeze effect. VOC ratios and other trace gases are used to identify air masses containing relatively fresh emissions that were often associated with offshore flow and re-circulated continental air associated with onshore flow conditions. With the prevailing southwesterly airflow pattern in the LAB throughout the daytime, the Pasadena ground site effectively functions as a receptor site and is used to characterize primary VOC emissions from downtown Los Angeles and to identify the corresponding secondary oxidation products. The chemical evolution of air masses as a function of the time of day is investigated in order to determine the relative impacts of primary emissions vs. secondary VOC products on OH reactivity and potential SOA formation. The reactivity of VOCs with the hydroxyl radical (OH) at the Pasadena site was dominated by the light hydrocarbons, isoprene, and oxygenated VOCs including aldehydes (secondary products) and alcohols (primary anthropogenic emissions). Toluene and benzaldehyde, both of which are associated with primary anthropogenic emissions, are the predominant VOC precursors to the

  17. Measurement of the mass energy-absorption coefficient of air for x-rays in the range from 3 to 60 keV.

    PubMed

    Buhr, H; Büermann, L; Gerlach, M; Krumrey, M; Rabus, H

    2012-12-21

    For the first time the absolute photon mass energy-absorption coefficient of air in the energy range of 10 to 60 keV has been measured with relative standard uncertainties below 1%, considerably smaller than those of up to 2% assumed for calculated data. For monochromatized synchrotron radiation from the electron storage ring BESSY II both the radiant power and the fraction of power deposited in dry air were measured using a cryogenic electrical substitution radiometer and a free air ionization chamber, respectively. The measured absorption coefficients were compared with state-of-the art calculations and showed an average deviation of 2% from calculations by Seltzer. However, they agree within 1% with data calculated earlier by Hubbell. In the course of this work, an improvement of the data analysis of a previous experimental determination of the mass energy-absorption coefficient of air in the range of 3 to 10 keV was found to be possible and corrected values of this preceding study are given.

  18. Who should take responsibility for decisions on internationally recommended datasets? The case of the mass concentration of mercury in air at saturation

    NASA Astrophysics Data System (ADS)

    Brown, Richard J. C.; Brewer, Paul J.; Ent, Hugo; Fisicaro, Paola; Horvat, Milena; Kim, Ki-Hyun; Quétel, Christophe R.

    2015-10-01

    This paper considers how decisions on internationally recommended datasets are made and implemented and, further, how the ownership of these decisions comes about. Examples are given of conventionally agreed data and values where the responsibility is clear and comes about through official designation or by common usage and practice over long time periods. The example of the dataset describing the mass concentration of mercury in air at saturation is discussed in detail. This is a case where there are now several competing datasets that are in disagreement with each other, some with historical authority and some more recent but, arguably, with more robust metrological traceability to the SI. Further, it is elaborated that there is no body charged with the responsibility to make a decision on an international recommendation for such a dataset. This has led to the situation where several competing datasets are in use simultaneously. Close parallels are drawn with the current debate over changes to the ozone absorption cross section, which has equal importance to the measurement of ozone amount fraction in air and to subsequent compliance with air quality legislation. It is noted that in the case of the ozone cross section there is already a committee appointed to deliberate over any change. We make the proposal that a similar committee, under the auspices of IUPAC or the CIPM’s CCQM (if it adopted a reference data function) could be formed to perform a similar role for the mass concentration of mercury in air at saturation.

  19. Influence of seasonality, air mass origin and particulate matter chemical composition on airborne bacterial community structure in the Po Valley, Italy.

    PubMed

    Innocente, Elena; Squizzato, Stefania; Visin, Flavia; Facca, Chiara; Rampazzo, Giancarlo; Bertolini, Valentina; Gandolfi, Isabella; Franzetti, Andrea; Ambrosini, Roberto; Bestetti, Giuseppina

    2017-03-28

    The integration of chemical and biological data in aerosol studies represents a new challenge in atmospheric science. In this perspective it will be possible to gain a clearer and deeper comprehension of biogeochemical cycles in the atmosphere. In this view, this study aimed to investigate the relationships occurring between bacterial populations and PM chemical composition in one of the most polluted and urbanized areas in Europe: the Po Valley (Italy). Moreover, seasonality, long- and short-range transports were also evaluated to investigate the influence on airborne bacterial communities. PM samples were collected in two cities of the Po Valley (Milan and Venice) characterized by different meteorological conditions and atmospheric pollutant sources. Samples were analysed for water-soluble inorganic ions (WSIIs) and bacterial community structure. Chemical and biological data were jointly processed by using redundancy discriminate analysis (RDA), while the influence of atmospheric circulation was evaluated by using wind ground data and back-trajectories analysis. Results showed strong seasonal shifts of bacterial community structure in both cities, while a different behaviour was observed for air mass circulation at Milan ad Venice sites: long-range transport significantly affected bacterial populations in Milan whereas local ground wind had more influence in the Venice area. Moreover, difference in taxonomic composition can be mostly addressed to the characteristics of sampling sites. This evidence could suggest that, while PM composition is influenced by long-range transport, bacterial populations are affected, besides transport, by other factors (i.e., season and sampling site location). This perspective allow to better understand and explain airborne bacterial community behaviour.

  20. Regression analysis in modeling of air surface temperature and factors affecting its value in Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim Mohammed; Jafri, Mohd. Zubir Mat; Lim, Hwee San; Abdullah, Khiruddin

    2012-10-01

    This study encompasses air surface temperature (AST) modeling in the lower atmosphere. Data of four atmosphere pollutant gases (CO, O3, CH4, and H2O) dataset, retrieved from the National Aeronautics and Space Administration Atmospheric Infrared Sounder (AIRS), from 2003 to 2008 was employed to develop a model to predict AST value in the Malaysian peninsula using the multiple regression method. For the entire period, the pollutants were highly correlated (R=0.821) with predicted AST. Comparisons among five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the southwest monsoon (SWM) season, within 1.3 K, and for in situ data, within 1 to 2 K. The validation results of AST with AST from AIRS showed high correlation coefficient (R=0.845 to 0.918), indicating the model's efficiency and accuracy. Statistical analysis in terms of β showed that H2O (0.565 to 1.746) tended to contribute significantly to high AST values during the northeast monsoon season. Generally, these results clearly indicate the advantage of using the satellite AIRS data and a correlation analysis study to investigate the impact of atmospheric greenhouse gases on AST over the Malaysian peninsula. A model was developed that is capable of retrieving the Malaysian peninsulan AST in all weather conditions, with total uncertainties ranging between 1 and 2 K.

  1. Measurement of the x-ray mass energy-absorption coefficient of air using 3 keV to 10 keV synchrotron radiation.

    PubMed

    Büermann, L; Grosswendt, B; Kramer, H-M; Selbach, H-J; Gerlach, M; Hoffmann, M; Krumrey, M

    2006-10-21

    For the first time absolute photon mass energy-absorption coefficients of air in the energy range 3 keV to 10 keV have been measured with relative standard uncertainties less than 1%, significantly smaller than those of up to 5% assumed hitherto for calculated data. Monochromatized synchrotron radiation was used to measure both the total radiant energy by means of silicon photodiodes calibrated against a cryogenic radiometer and the fraction of radiant energy that is deposited in dry air by means of a free air ionization chamber. The measured ionization charge was converted into energy absorbed in air by calculated effective W values of photons as a function of their energy based on new measurements of the W values in dry air for electron kinetic energies between 1 keV and 7 keV, also presented in this work. The measured absorption coefficients were compared with state-of-the art calculations and found to agree within 0.7% with data calculated earlier by Hubbell at energies above 4 keV but were found to differ by values up to 2.1% at 10 keV from more recent calculations of Seltzer.

  2. Bone Mineral Density in Sheehan's Syndrome; Prevalence of Low Bone Mass and Associated Factors.

    PubMed

    Chihaoui, Melika; Yazidi, Meriem; Chaker, Fatma; Belouidhnine, Manel; Kanoun, Faouzi; Lamine, Faiza; Ftouhi, Bochra; Sahli, Hela; Slimane, Hedia

    2016-10-01

    Hypopituitarism is a known cause of bone mineral loss. This study aimed to evaluate the frequency of osteopenia and osteoporosis in patients with Sheehan's syndrome (SS) and to determine the risk factors. This is a retrospective study of 60 cases of SS that have had a bone mineral density (BMD) measurement. Clinical, biological, and therapeutic data were collected. The parameters of osteodensitometry at the femoral neck and the lumbar spine of 60 patients with SS were compared with those of 60 age-, height-, and weight-matched control women. The mean age at BMD measurement was 49.4 ± 9.9 yr (range: 25-76 yr). The mean duration of SS was 19.3 ± 8.5 yr (range: 3-41 yr). All patients had corticotropin deficiency and were treated with hydrocortisone at a mean daily dose of 26.3 ± 4.1 mg. Fifty-seven patients (95%) had thyrotropin deficiency and were treated with thyroxine at a mean daily dose of 124.3 ± 47.4 µg. Thirty-five of the 49 patients, aged less than 50 yr at diagnosis and having gonadotropin deficiency (71.4%), had estrogen-progesterone substitution. Osteopenia was present in 25 patients (41.7%) and osteoporosis in 21 (35.0%). The BMD was significantly lower in the group with SS than in the control group (p < 0.001). The odds ratio of osteopenia-osteoporosis was 3.1 (95% confidence interval: 1.4-6.8) at the femoral neck and 3.7 (95% confidence interval: 1.7-7.8) at the lumbar spine. The lumbar spine was more frequently affected by low bone mineral mass (p < 0.05). The duration of the disease and the daily dose of hydrocortisone were independently and inversely associated with BMD at the femoral neck. The daily dose of thyroxine was independently and inversely associated with BMD at the lumbar spine. Estrogen-progesterone replacement therapy was not associated with BMD. Low bone mineral mass was very common in patients with SS. The lumbar spine was more frequently affected. The duration of the disease and the doses of

  3. Geotechnical factors and guidelines for storage of compressed air in solution-mined salt cavities

    NASA Astrophysics Data System (ADS)

    Allen, R. D.; Doherty, T. J.; Thoms, R. L.

    1982-05-01

    The state of knowledge about utilization of solution mined salt cavities for CAES including laboratory experiments, numerical modeling, field characterization, solution mining experience, and operating parameters is outlined. Topics evaluated include: cavern geometry and size; long term creep and creep rupture of rock salt; effects of pressure and temperature loading rates; low frequency fatigue; progressive deterioration of salt fabric with possible air penetration; cavern monitoring methods; and salt properties at nonambient conditions. The only CAES operational facility in the world uses two solution mined salt cavern for air storage and is operating successfully. Stability critera for solution mined salt caverns.

  4. Determinative factors of competitive advantage between aerobic bacteria for niches at the air-liquid interface.

    PubMed

    Yamamoto, Kyosuke; Haruta, Shin; Kato, Souichiro; Ishii, Masaharu; Igarashi, Yasuo

    2010-01-01

    We focused on bacterial interspecies relationships at the air-liquid interface where the formation of pellicles by aerobes was observed. Although an obligate aerobe (Brevibacillus sp. M1-5) was initially dominant in the pellicle population, a facultative aerobe (Pseudoxanthomonas sp. M1-3) emerged and the viability of M1-5 rapidly decreased due to severe competition for oxygen. Supplementation of the medium with carbohydrates allowed the two species to coexist at the air-liquid interface. These results indicate that the population dynamics within pellicles are primarily governed by oxygen utilization which was affected by a combination of carbon sources.

  5. Effects of Thermal Mass, Window Size, and Night-Time Ventilation on Peak Indoor Air Temperature in the Warm-Humid Climate of Ghana

    PubMed Central

    Amos-Abanyie, S.; Akuffo, F. O.; Kutin-Sanwu, V.

    2013-01-01

    Most office buildings in the warm-humid sub-Saharan countries experience high cooling load because of the predominant use of sandcrete blocks which are of low thermal mass in construction and extensive use of glazing. Relatively, low night-time temperatures are not harnessed in cooling buildings because office openings remain closed after work hours. An optimization was performed through a sensitivity analysis-based simulation, using the Energy Plus (E+) simulation software to assess the effects of thermal mass, window size, and night ventilation on peak indoor air temperature (PIAT). An experimental system was designed based on the features of the most promising simulation model, constructed and monitored, and the experimental data used to validate the simulation model. The results show that an optimization of thermal mass and window size coupled with activation of night-time ventilation provides a synergistic effect to obtain reduced peak indoor air temperature. An expression that predicts, indoor maximum temperature has been derived for models of various thermal masses. PMID:23878528

  6. Factors affecting decay of Salmonella Birkenhead and coliphage MS2 during mesophilic anaerobic digestion and air drying of sewage sludge.

    PubMed

    Mondal, Tania; Rouch, Duncan A; Thurbon, Nerida; Smith, Stephen R; Deighton, Margaret A

    2015-06-01

    Factors affecting the decay of Salmonella Birkenhead and coliphage, as representatives of bacterial and viral pathogens, respectively, during mesophilic anaerobic digestion (MAD) and air drying treatment of anaerobically digested sewage sludge were investigated. Controlled concentrations of S. Birkenhead were inoculated into non-sterile, autoclaved, γ-irradiated and nutrient-supplemented sludge and cultures were incubated at 37 °C (MAD sludge treatment temperature) or 20 °C (summer air drying sludge treatment temperature). Nutrient limitation caused by microbial competition was the principal mechanism responsible for the decay of S. Birkenhead by MAD and during air drying of digested sludge. The effects of protease activity in sludge on MS2 coliphage decay in digested and air dried sludge were also investigated. MS2 coliphage showed a 3.0-3.5 log10 reduction during incubation with sludge-protease extracts at 37 °C for 25 h. Proteases produced by indigenous microbes in sludge potentially increase coliphage inactivation and may therefore have a significant role in the decay of enteric viruses in sewage sludge. The results help to explain the loss of viability of enteric bacteria and viral pathogens with treatment process time and contribute to fundamental understanding of the various biotic inactivation mechanisms operating in sludge treatment processes at mesophilic and ambient temperatures.

  7. Low Bone Mass Is a Risk Factor in Periodontal Disease-Related Tooth Loss in Patients with Intellectual Disability

    PubMed Central

    Numoto, Yoko; Mori, Takayuki; Maeda, Shigeru; Tomoyasu, Yumiko; Higuchi, Hitoshi; Egusa, Masahiko; Miyawaki, Takuya

    2013-01-01

    Teeth are fundamental to maintaining good quality of life, but are often lost prematurely in individuals with intellectual disability. Furthermore, since bone mass decreases in menopausal women, women with intellectual disability have an augmented risk of losing their teeth. However, the relationship between periodontal disease-related tooth loss and bone mass has never been studied specifically in patients with intellectual disability. This study evaluated this relationship in a retrospective cohort study. Participants were female dental patients aged between 20 and 50 years and with an intellectual disability, who were treated in the Special Needs Dentistry unit of the Okayama University Hospital from January 2009 to March 2010. Logistic regression analysis was used to analyze which factors affect periodontal disease-related tooth loss. Information relating to 12 predictor variables, including age and bone mass level, was derived from medical records. The 27 subjects had a total of 704 teeth at the time of initial examination, but 20 teeth (2.8%) had been lost owing to periodontal disease by the time bone mass measurements were recorded. Results of the multinomial logistic regression analysis indicated a significant odds ratio for three items: number of missing teeth at the time of initial examination, bone mass, and living environment. This result suggests that low bone mass is an independent risk factor in tooth loss secondary to periodontal disease in patients with intellectual disability. Dentists should thus take account of this heightened risk of tooth loss when caring for post-menopausal women with intellectual disability. PMID:24358063

  8. Simultaneous factor analysis of organic particle and gas mass spectra: AMS and PTR-MS measurements at an urban site

    NASA Astrophysics Data System (ADS)

    Slowik, J. G.; Vlasenko, A.; McGuire, M.; Evans, G. J.; Abbatt, J. P. D.

    2009-03-01

    During the winter component of the SPORT (Seasonal Particle Observations in the Region of Toronto) field campaign, particulate non-refractory chemical composition and concentration of selected volatile organic compounds (VOCs) were measured by an Aerodyne time-of-flight aerosol mass spectrometer (AMS) and a proton transfer reaction-mass spectrometer (PTR-MS), respectively. Sampling was performed in downtown Toronto ~15 m from a major road. The mass spectra from the AMS and PTR-MS were combined into a unified dataset, which was analyzed using positive matrix factorization (PMF). The two instruments were given equal weight in the PMF analysis by application of a scaling factor to the uncertainties of each instrument. A residual based metric, Δesc, was used to evaluate the relative weight. The PMF analysis yielded a 5-factor solution that included factors characteristic of regional transport, local traffic emissions, charbroiling, and oxidative processing. The unified dataset provides information on particle and VOC sources and atmospheric processing that cannot be obtained from the datasets of the individual instruments, such as apportionment of oxygenated VOCs to direct emission sources vs. secondary reaction products, improved correlation of oxygenated aerosol factors with photochemical age, and increased detail regarding the composition of oxygenated organic aerosol factors. This analysis represents the first application of PMF to a unified AMS/PTR-MS dataset.

  9. Simultaneous factor analysis of organic particle and gas mass spectra: AMS and PTR-MS measurements at an urban site

    NASA Astrophysics Data System (ADS)

    Slowik, J. G.; Vlasenko, A.; McGuire, M.; Evans, G. J.; Abbatt, J. P. D.

    2010-02-01

    During the winter component of the SPORT (Seasonal Particle Observations in the Region of Toronto) field campaign, particulate non-refractory chemical composition and concentration of selected volatile organic compounds (VOCs) were measured by an Aerodyne time-of-flight aerosol mass spectrometer (AMS) and a proton transfer reaction-mass spectrometer (PTR-MS), respectively. Sampling was performed in downtown Toronto ~15 m from a major road. The mass spectra from the AMS and PTR-MS were combined into a unified dataset, which was analysed using positive matrix factorization (PMF). The two instruments were given balanced weight in the PMF analysis by the application of a scaling factor to the uncertainties of each instrument. A residual based metric, Δesc, was used to evaluate the instrument relative weight within each solution. The PMF analysis yielded a 6-factor solution that included factors characteristic of regional transport, local traffic emissions, charbroiling and oxidative processing. The unified dataset provides information on emission sources (particle and VOC) and atmospheric processing that cannot be obtained from the datasets of the individual instruments: (1) apportionment of oxygenated VOCs to either direct emission sources or secondary reaction products; (2) improved correlation of oxygenated aerosol factors with photochemical age; and (3) increased detail regarding the composition of oxygenated organic aerosol factors. This analysis represents the first application of PMF to a unified AMS/PTR-MS dataset.

  10. Workplace protection factor measurements on powered air-purifying respirators at a secondary lead smelter: results and discussion.

    PubMed

    Myers, W R; Peach, M J; Cutright, K; Iskander, W

    1984-10-01

    A study was conducted at a secondary lead smelter to evaluate the workplace performance of the 3M W-344 and Racal AH3 powered air-purifying respirators equipped with helmets and high efficiency filters. The research protocol developed for the study has been described in a companion paper. The results of the study indicate that the mean lead concentrations, measured inside the facepiece of both PAPRs, were significantly less than the OSHA lead exposure limit of 50 micrograms/m3. The means of the workplace protection factor measurements on both PAPRs were significantly less than the PAPR selection guide protection factor classification of 1000. Correlation analysis of preshift quantitative fit factors and corresponding workplace protection factors indicated no linear association between these two measures of performance. This finding suggests that for PAPRs equipped with helmets and high efficiency filters quantitative fit factors as presently determined are not indicative of the workplace protection which the respirators provide. Since the PAPR protection factor classification of 1000 was originally based on quantitative fit factors, the lack of a demonstrated association between quantitative fit factors and workplace protection as found in this study may explain why their performance was significantly less than expected.

  11. Levels of 25 trace elements in high-volume air filter samples from Seville (2001-2002): Sources, enrichment factors and temporal variations

    NASA Astrophysics Data System (ADS)

    Enamorado-Báez, S. M.; Gómez-Guzmán, J. M.; Chamizo, E.; Abril, J. M.

    2015-03-01

    The measurement of trace element concentration in aerosols is of interest for environmental studies and for human health assessment. The temporal variability of total suspended particles (TSP) and its elemental composition in Seville, in SW Spain, is of particular complexity since Atlantic air masses and Saharan Dust Intrusions (SDI) overlap to local natural and anthropogenic sources. This paper is aimed to study the temporal evolution (in a monthly basis) of the concentrations of 25 trace elements, determined by ICP-MS, in high-volume air filter samples from Seville, covering a two-year period: 2001-2002. The mean TSP value for this period was 79.7 μg m- 3 and showed peak values in August 2001 and June 2002, likely related to SDI. Enrichment factors (EF) for Se, Sb and Zn and Pb were above 100, which revealed their anthropogenic sources. The comparison among EF from Seville and Huelva, a highly industrialized city nearby Seville, showed higher levels of anthropogenic elements there than in Seville. Simulations of the transport/dispersion of pollutants starting in Huelva confirm that air pollutants can reach Seville in the course of around 6 hours although they do not contribute significantly to the levels found in this city. A significant temporal correlation was found between elements which have a common source, being crustal (Al, Ti, Be, Co, Cs, Fe, Cr, Mn, U, Sr and Th) or anthropogenic sources (Zn, Pb, Cd). The temporal variations of those crustal elements are similar and related with the TSP levels for both years, with the clearly visible peaks probably related with the Saharan dust intrusion.

  12. Left Ventricular Mass and Arterial Compliance: Relation to Coronary Heart Disease and its Risk Factors in South Indian Adults

    PubMed Central

    Kumaran, K; Fall, Caroline HD; Martyn, Christopher N; Vijayakumar, M; Stein, Claudia E; Shier, Rosie

    2017-01-01

    Structured Abstract Background Rates of coronary heart disease (CHD) in India are rising, and are now similar to those in Western countries. The prevalence of conventional CHD risk factors such as hypercholesterolaemia, hypertension, smoking and obesity, tend to be lower in Indian than Western populations, and fail to explain these high rates of disease. Increased left ventricular mass (LV mass) and decreased arterial compliance predict a higher risk of CHD in Western populations, but there are no published data from India. We have measured LV mass and arterial compliance, and examined their relation to CHD and other known risk factors, in men and women living in Mysore, South India. Methods We examined 435 men and women born in Mysore during 1934-1953. LV mass was measured by echocardiography and arterial compliance (derived from pulse wave velocity {PWV}) was measured by a non-invasive optical method in three arterial segments. Results The mean LV mass was 149g (SD 37) in men and 125g (SD 32) in women. The mean PWV was 4.14m/s in the aorto-radial, 3.28m/s in the aorto-femoral and 13.59m/s in the femoro-popliteal-posterior tibial segments. LV mass and PWV were positively correlated with each other and with systolic and diastolic blood pressures, non-insulin dependant diabetes mellitus, fasting plasma glucose, insulin, proinsulin concentrations and serum triglyceride concentrations (p<0.05 for all), independently of age, sex and body size. In addition, LV mass correlated negatively with fasting serum HDL-cholesterol (p=0.02). Higher LV mass was associated with an increased risk of CHD (p=0.05). Conclusions The mean LV mass in this Indian population is low compared with Western populations, though as in the West, increased LV mass is associated with an increased risk of CHD. Greater LV mass and reduced arterial compliance are associated with higher levels of many known CHD risk factors especially with those which form the Insulin Resistance Syndrome. PMID:11959376

  13. SOURCE APPORTIONMENT OF PM 2.5 AND CARBON IN SEATTLE USING CHEMICAL MASS BALANCE AND POSITIVE MATRIX FACTORIZATION

    EPA Science Inventory

    Three years of PM2.5 speciated data were collected and chemically analyzed using the IMPROVE protocol at the Beacon Hill site in Seattle. The data were analyzed by the Chemical Mass Balance Version 8 (CMB8) and Positive Matrix Factorization (PMF) source apportionment models. T...

  14. Socio-Cognitive and Nutritional Factors Associated with Body Mass Index in Children and Adolescents: Possibilities for Childhood Obesity Prevention

    ERIC Educational Resources Information Center

    O'Dea, Jennifer A.; Wilson, Rachel

    2006-01-01

    A large national study of schoolchildren aged 6-18 years was conducted to assess nutritional and socio-cognitive factors associated with body mass index (BMI). A questionnaire was used to assess nutritional quality of breakfast, importance of physical activity and food variety score, among 4441 students from randomly selected schools in all states…

  15. 75 FR 72739 - Compliance Testing Procedures: Correction Factor for Room Air Conditioners

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-26

    ... of Energy November 15, 2010 Petition for Rulemaking Petition of the Association of the Home Appliance... terms of energy efficiency and environmental protection. New appliances often represent the most... air conditioner has technically incorrect ratings, does not qualify for Energy Star, or fails to...

  16. Factors Affecting the Transfer of Basic Combat Skills Training in the Air Force

    DTIC Science & Technology

    2006-03-01

    In 2004 civilian corporations spent $80 billion on formal training programs (Clark & Kwinn, 2005). In 2005, the USAF planned to spend over $9M in...Studies, Vol. 9, 1-16. Beck, G. M. (2004). An analysis of the Air Force Basic Comunications Officer Training course : the impact of trainee and

  17. Air Traffic Communication in a Second Language: Implications of Cognitive Factors for Training and Assessment

    ERIC Educational Resources Information Center

    Farris, Candace; Trofimovich, Pavel; Segalowitz, Norman; Gatbonton, Elizabeth

    2008-01-01

    This study investigated the effects of second language (L2) proficiency and task-induced cognitive workload on participants' speech production and retention of information in an environment designed to simulate the demands faced by pilots receiving instructions from air-traffic controllers. Three groups of 20 participants (one…

  18. Blood pressure, dyslipidemia and inflammatory factors are related to body mass index in scholar adolescents

    PubMed Central

    Ghomari-Boukhatem, Hanane; Bouchouicha, Assia; Mekki, Khedidja; Chenni, Karima; Belhadj, Mohamed

    2016-01-01

    Introduction Obesity is associated with increased occurrence of numerous diseases, including hypertension, dyslipidemia, insulin resistance, diabetes, and atherosclerosis. Blood pressure (BP), dyslipidemia, and inflammation markers and their relationships with body mass index (BMI) were determined in scholar adolescents. Material and methods Adolescents (n = 210) (sex ratio G/B = 106/104; 11 to 16 years) were recruited in three colleges of Oran city. Anthropometric parameters were measured to classify adolescents as thin (T), normal weight (NW), overweight (OW), or obese (O). Waist circumference (WC) and BP were measured, and serum glucose, uric acid, urea, lipid parameters, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), C-reactive protein (CRP), insulin, leptin, and adiponectin were analyzed. Results Adolescents were classified according to their BMI as T (15%), NW (63%), OW (13%), and O (9%). Compared to NW, increased values of WC, BP (p < 0.001), and glucose (p < 0.01) were noted in OW and O groups. Total cholesterol (TC) level was elevated in O adolescents (p < 0.01). Increased low-density lipoprotein cholesterol (LDL-C) in OW (p < 0.05) and O (p < 0.01), and reduced high-density lipoprotein cholesterol (HDL-C) concentrations were noted in both OW and O groups (p < 0.05), compared to NW. Elevated triglyceride (TG) values and TG : HDL-C ratio were observed in OW (p < 0.05) and O (p < 0.01). High values of uric acid were noted in OW and O adolescents (p < 0.01). Compared to NW, there was no significant difference in IL-1β whereas IL-6 was elevated in T (p < 0.05), OW (p < 0.01) and O (p < 0.001). Leptin, TNF-α, and CRP concentrations were significantly increased (p < 0.001), whereas adiponectin values were decreased in both OW and O groups (p < 0.01), compared to NW. Conclusions Significant associations were noted between WC, BP, dyslipidemia, inflammation markers, and BMI, indicating that both OW and O adolescents have a

  19. Salivary nerve growth factor response to intense stress: effect of sex and body mass index.

    PubMed

    Taylor, Marcus K; Laurent, Heidemarie K; Larson, Gerald E; Rauh, Mitchell J; Hiller Lauby, Melissa D; Granger, Douglas A

    2014-05-01

    Ample evidence links stress to psychiatric and neurological disease. Although many studies examine stress hormone secretion and receptor activity, exciting new developments signify a shift in focus to neuromodulatory systems influencing neuronal development, survival, and neuroplasticity. The purpose of this study was to characterize salivary nerve growth factor (sNGF) responses to intense stress exposure in healthy military members undergoing survival training. A second purpose was to explore effects of age, sex, education, and body mass index (BMI). One hundred sixteen military members (80% male) were studied before, during, and 24 h after a stressful mock-captivity exercise. sNGF was measured at all three time points. Reactivity, recovery, and residual elevation of sNGF were computed. General linear modeling with repeated measures evaluated effect of stress exposure, as well as the roles of age, sex, education, and BMI. sNGF increased 137% from baseline to intense stress. During recovery, sNGF remained elevated an average of 67% above baseline (i.e., residual elevation). Men showed greater sNGF reactivity than women quantified by larger absolute T1-T2Δ (+148.1 pg/mL vs. +64.9 pg/mL, p<0.017). A noteworthy trend of higher sNGF concentrations in low BMI participants was observed (p=0.058). No effects of age or education were shown. This study shows substantial reactivity and residual elevation of sNGF in response to intense stress exposure in healthy humans. Further research is needed to refine the sNGF assay, fully characterize the sNGF stress response, delineate correlates and mechanisms, and validate therapeutic applications.

  20. Glycan structure of Gc Protein-derived Macrophage Activating Factor as revealed by mass spectrometry.

    PubMed

    Borges, Chad R; Rehder, Douglas S

    2016-09-15

    Disagreement exists regarding the O-glycan structure attached to human vitamin D binding protein (DBP). Previously reported evidence indicated that the O-glycan of the Gc1S allele product is the linear core 1 NeuNAc-Gal-GalNAc-Thr trisaccharide. Here, glycan structural evidence is provided from glycan linkage analysis and over 30 serial glycosidase-digestion experiments which were followed by analysis of the intact protein by electrospray ionization mass spectrometry (ESI-MS). Results demonstrate that the O-glycan from the Gc1F protein is the same linear trisaccharide found on the Gc1S protein and that the hexose residue is galactose. In addition, the putative anti-cancer derivative of DBP known as Gc Protein-derived Macrophage Activating Factor (GcMAF, which is formed by the combined action of β-galactosidase and neuraminidase upon DBP) was analyzed intact by ESI-MS, revealing that the activating E. coli β-galactosidase cleaves nothing from the protein-leaving the glycan structure of active GcMAF as a Gal-GalNAc-Thr disaccharide, regardless of the order in which β-galactosidase and neuraminidase are applied. Moreover, glycosidase digestion results show that α-N-Acetylgalactosamindase (nagalase) lacks endoglycosidic function and only cleaves the DBP O-glycan once it has been trimmed down to a GalNAc-Thr monosaccharide-precluding the possibility of this enzyme removing the O-glycan trisaccharide from cancer-patient DBP in vivo.

  1. [Determination of short-chain chlorinated paraffins in ambient air using high-volume sampling combined with high resolutimi gas chromatography-electron capture negative ion-low resolution mass spectrometry].

    PubMed

    Shi, Loimeng; Gao, Yuan; Hou, Xiaohong; Zhang, Haijun; Zhang, Yichi; Chen, Jiping

    2016-02-01

    An analytical method for quantifying short-chain chlorinated paraffins (SCCPs) in ambient air using high-volume sampling combined with high resolution gas chromatography-electron capture negative ion-low resolution mass spectrometry ( HRGC-ECNI-LRMS) was developed. An acidified silica gel column and a basic alumina column were used to optimize the cleanup procedures. The results showed a good linearity (R2>0. 99) between the total response factors and the degree of chlorination of SCCPs in the content range of 58. 1%-63. 3%. The limits of detection (S/N ≥3) and the limits of quantification (S/N ≥ 10) were 4. 2 and 12 µg, respectively. The method detection limit (MDL) for SCCPs was 0. 34 ng/m3 (n = 7). The recoveries of SCCPs in air samples were in the range of 81. 9% to 94. 2%. It is demonstrated that the method is suitable for the quantitative analysis of SCCPs in air samples.

  2. Detection of Free Tropospheric Air Masses With High So2 and Aerosol Concentrations: Evidence For New Aerosol Particle Formation By H2so4/h2o Nucleation

    NASA Astrophysics Data System (ADS)

    Katragkou, E.; Wilhelm, S.; Kiendler, A.; Arnold, F.; Minikin, A.; Schlager, H.; van Velthoven, P.

    Sulfur dioxide and aerosol measurements were performed in the free troposphere (FT) and the Planetary Boundary Layer (PBL) above continental Europe. The measure- ments took place on board of the German research aircraft "Falcon" in 18 April 2001 as a part of the SCAVEX campaign. A novel aircraft based CIMS (Chemical Ion- ization Mass Spectrometry) instrument equipped with an ion trap mass spectrometer (ITMS) with a low detection limit (50pptv) and a high time resolution (1.3s) operated by MPI-K was used to perform the SO2 measurements. For the aerosol measurements DLR-IPA operated a Condensation Particle Size Analyzer, detecting particles with diameters d > 4, 7, 9 and 20nm and a PCASP-100X aerosol spectrometer probe (d > 100nm). In the measurements made mostly around 5000m altitude SO2 rich air masses were occasionally observed with SO2 VMR of up to 2900pptv. The strong SO2 pollu- tion was due to fast vertical transport of polluted continental PBL air and small-scale deep convection, as indicated by the 5-day backward 3D trajectories. These observa- tions of strong SO2 pollution have interesting implications for aerosol processes, in- cluding efficient formation of gaseous sulfuric acid (GSA) and new aerosol particles. They also imply fast growth of freshly nucleated aerosol particles, which increases the chance for new particles to grow to the size of a CCN. Our analysis indicates the occurrence of new particle formation by H2SO4/H2O nucleation and fast new particle growth by H2SO4/H2O condensation and self-coagulation in the different air masses encountered during the flight.

  3. Programmed for Failure? The Colonial Factor in the Mass Literacy Campaign in Nigeria, 1946-1956

    ERIC Educational Resources Information Center

    Omolewa, Michael

    2008-01-01

    This paper is an account of the earliest attempt in Africa to make education available to all within the context of what has been called fundamental education or a mass education programme. The paper draws attention to how the demand for mass education during the Second World War years was met by the British government, which, following what…

  4. The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations.

    PubMed

    Weaver, C M; Gordon, C M; Janz, K F; Kalkwarf, H J; Lappe, J M; Lewis, R; O'Karma, M; Wallace, T C; Zemel, B S

    2016-04-01

    Lifestyle choices influence 20-40 % of adult peak bone mass. Therefore, optimization of lifestyle factors known to influence peak bone mass and strength is an important strategy aimed at reducing risk of osteoporosis or low bone mass later in life. The National Osteoporosis Foundation has issued this scientific statement to provide evidence-based guidance and a national implementation strategy for the purpose of helping individuals achieve maximal peak bone mass early in life. In this scientific statement, we (1) report the results of an evidence-based review of the literature since 2000 on factors that influence achieving the full genetic potential for skeletal mass; (2) recommend lifestyle choices that promote maximal bone health throughout the lifespan; (3) outline a research agenda to address current gaps; and (4) identify implementation strategies. We conducted a systematic review of the role of individual nutrients, food patterns, special issues, contraceptives, and physical activity on bone mass and strength development in youth. An evidence grading system was applied to describe the strength of available evidence on these individual modifiable lifestyle factors that may (or may not) influence the development of peak bone mass (Table 1). A summary of the grades for each of these factors is given below. We describe the underpinning biology of these relationships as well as other factors for which a systematic review approach was not possible. Articles published since 2000, all of which followed the report by Heaney et al. [1] published in that year, were considered for this scientific statement. This current review is a systematic update of the previous review conducted by the National Osteoporosis Foundation [1]. [Table: see text] Considering the evidence-based literature review, we recommend lifestyle choices that promote maximal bone health from childhood through young to late adolescence and outline a research agenda to address current gaps in knowledge

  5. Observation of the transport of polluted air masses from the northeastern United States to Cape Sable Island, Nova Scotia, Canada, during the 1993 NARE summer intensive

    NASA Astrophysics Data System (ADS)

    Knapp, K. G.; Balsley, B. B.; Jensen, M. L.; Hanson, H. P.; Birks, J. W.

    1998-06-01

    Vertical profiles of ozone, temperature, pressure, and water vapor mass mixing ratio obtained using a parafoil kite platform during the North Atlantic Regional Experiment (NARE) 1993 summer intensive at Cape Sable Island, Nova Scotia, Canada, demonstrate the of use of kite platforms for the collection of vertically and temporally resolved data over a fixed location. During the period August 8-28, 1993, 39 profiles of the lower atmosphere were collected. Data collected as part of this field campaign illustrate the complex vertical stratification and temporal variability of pollutants transported into the Maritime Provinces of Canada. Transport phenomena resulted in pollution events in which ozone at the ground level remained in the 20-40 parts per billion by volume (ppbv) range, while mixing ratios of 90-130 ppbv were observed above ˜300 m. Back trajectories indicate that these highly elevated levels of ozone are attributable to source regions in the heavily industrialized northeastern United States. Vertical stratification of the lower atmosphere was also present during transport of Canadian air to the sampling site, with layers of both elevated and diminished ozone observed, while marine air did not exhibit layering characteristic of air masses originating from continental source regions.

  6. Development of a thermal desorption gas chromatography-mass spectrometry method for quantitative determination of haloanisoles and halophenols in wineries' ambient air.

    PubMed

    Camino-Sánchez, F J; Ruiz-García, J; Zafra-Gómez, A

    2013-08-30

    An analytical method for the detection and quantification of haloanisoles and their corresponding halophenols in wineries' ambient air was developed. The target analytes were haloanisoles and halophenols, reported by previous scientific literature as responsible for wine taint. A calibrated pump and active tubes filled with Tenax GR™ were used for sampling. These tubes were thermally desorbed and analyzed using gas chromatography-triple quadrupole mass spectrometry in the selected reaction monitoring mode. The adsorption efficiencies of five commercial sampling tubes filled with different materials were evaluated. The efficiencies of the selected adsorbent were close to 100% for all sampled compounds. Desorption, chromatographic and mass spectrometric conditions were accurately optimized allowing very low limits of quantification and wide linear ranges. The limits of quantification in ambient air ranged from 0.8pgtube(-1) for 2,4,6-trichlorophenol, to 28pgtube(-1) for pentachlorophenol. These results are of great importance because human sensory threshold for haloanisoles is very low. The chromatographic method was also validated and the instrumental precision and trueness were established, a maximum RSD of 9% and a mean recovery of 91-106% were obtained. The proposed method involves an easy and sensitive technique for the early detection of haloanisoles and their precursor halophenols in ambient air avoiding contamination of wine or winery facilities.

  7. Ambient air particle transport into the effluent of a cold atmospheric-pressure argon plasma jet investigated by molecular beam mass spectrometry

    NASA Astrophysics Data System (ADS)

    Dünnbier, M.; Schmidt-Bleker, A.; Winter, J.; Wolfram, M.; Hippler, R.; Weltmann, K.-D.; Reuter, S.

    2013-10-01

    Ambient air species, which are transported into the active effluent of an atmospheric-pressure plasma jet result in highly reactive oxygen and nitrogen species (RONS). Especially for the envisaged application field of plasma medicine, these RONS are responsible for strong biological responses. In this work, the effect of ambient air transport into the effluent of an atmospheric-pressure plasma argon jet on the on-axis densities of nitrogen, oxygen and argon was investigated by means of absolutely calibrated molecular beam mass spectrometry (MBMS). According to biomedical experiments a (bottomless) Petri dish was installed in front of the MBMS. In the following, the near flow field is referring to the region close to the nozzle exit and the far flow field is referring to the region beyond that. The absolute on-axis densities were obtained by three different methods, for the near flow field with VUV-absorption technique, for the far flow field with the MBMS and the total flow field was calculated with a computational fluid dynamics (CFD) simulation. The results of the ambient air particle densities of all independent methods were compared and showed an excellent agreement. Therefore the transport processes of ambient air species can be measured for the whole effluent of an atmospheric-pressure plasma jet. Additionally, with the validation of the simulation it is possible in future to calculate the ambient species transport for various gas fluxes in the same turbulent flow regime. Comparing the on-axis densities obtained with an ignited and with a non-ignited plasma jet shows that for the investigated parameters, the main influence on the ambient air species transport is due to the increased temperature in the case when the jet is switched on. Moreover, the presence of positive ions (e.g. ArN_{2}^{+} ) formed due to the interaction of plasma-produced particles and ambient air species, which are transported into the effluent, is shown.

  8. Geotechnical factors and guidelines for storage of compressed air in solution-mined salt cavities

    SciTech Connect

    Allen, R.D.; Doherty, T.J.; Thoms, R.L.

    1982-05-01

    The state of knowledge about utilization of solution-mined salt cavities for CAES including laboratory experiments, numerical modeling, field characterization, solution mining experience, and operating parameters is outlined in this report. Topics evaluated in recent studies include: cavern geometry and size; long-term creep and creep rupture of rock salt; effects of pressure and temperature loading rates; low frequency fatigue; progressive deterioration of salt fabric with possible air penetration; cavern monitoring methods; and salt properties at nonambient conditions. Currently, the only CAES operational facility in the world is located at Huntorf, West Germany. This CAES facility uses two solution-mined salt caverns for air storage and has been operating successfully for more than 2 years. Stability criteria for solution-mined salt caverns from the Huntorf facility and recent field and laboratory studies are included in this report.

  9. Stationwide environmental baseline survey and related environmental factors, Ontario Air National Guard Station, California

    SciTech Connect

    1996-11-26

    This Environmental Baseline Survey (EBS) has been prepared to document the environmental condition of real property at Ontario Air National Guard Station (ANGS), California, resulting from the storage, release, and disposal of hazardous substances and petroleum products and their derivatives over the installations history. This EBS is also used by the Air Force to meet its obligations under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), 42 United States Code Section 9620(h), as amended by the Community Environmental Response Facilitation Act (CERFA) (Public Law 102-426). Table ES-1 list all uncontaminated property based on information obtained through a records search, interviews, and visual site inspections at Ontario ANGS. Figure ES-1 depicts their respective locations.

  10. [Analysing noise levels in dental environment. Air turbine sound response to various physical factors].

    PubMed

    Oka, S

    1989-10-01

    Dental Air Turbine sound depends on the mechanical performance such as rotation and it is impossible to neglect connections of the sound with fluid mechanics and acoustics. Turbine sound must be considered from the standpoint of the sound pressure level and frequency component. In this study, the sound samples was measured and analysed in octave band spectrum. Turbine sound has three resonance bands of the frequency with the range from 0 to 1,600 Hz and the resonance band increased as air pressure increased. The frequency of the second resonance band decreased as the cutting load and cutting point diameter increased. Damping of the second resonance band frequency shifted downward by polishing point.

  11. An Investigation of Environmental Factors that Influence Knowledge Transfer in the Air Force

    DTIC Science & Technology

    2007-11-02

    Another view of knowledge sees it as either explicit or tacit. First described by Michael Polanyi (1958) in his book, Personal Knowledge, and further...1998b). “People,” Air Force Magazine, 84: 44 (May 2001). 130 Polanyi , Michael . Personal Knowledge. Chicago: University of Chicago Press...1958. Polanyi , Michael . The Tacit Dimension. New York: Doubleday & Company, 1966. Rueve, Ryan J. Knowledge Management in the Cost Analysis

  12. Development of an empirical model to estimate real-world fine particulate matter emission factors: the traffic air quality model.

    PubMed

    Soliman, Ahmed S M; Jacko, Robert B; Palmer, George M

    2006-11-01

    The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds < 50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds > 80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold.

  13. Sensitive and comprehensive detection of chemical warfare agents in air by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow introduction.

    PubMed

    Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Yamashiro, Shigeharu; Sano, Yasuhiro; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Sekiguchi, Hiroyuki; Iura, Kazumitsu; Nagashima, Hisayuki; Nagoya, Tomoki; Tsuge, Kouichiro; Ohsawa, Isaac; Okumura, Akihiko; Takada, Yasuaki; Ezawa, Naoya; Watanabe, Susumu; Hashimoto, Hiroaki

    2014-05-06

    A highly sensitive and specific real-time field-deployable detection technology, based on counterflow air introduction atmospheric pressure chemical ionization, has been developed for a wide range of chemical warfare agents (CWAs) comprising gaseous (two blood agents, three choking agents), volatile (six nerve gases and one precursor agent, five blister agents), and nonvolatile (three lachrymators, three vomiting agents) agents in air. The approach can afford effective chemical ionization, in both positive and negative ion modes, for ion trap multiple-stage mass spectrometry (MS(n)). The volatile and nonvolatile CWAs tested provided characteristic ions, which were fragmented into MS(3) product ions in positive and negative ion modes. Portions of the fragment ions were assigned by laboratory hybrid mass spectrometry (MS) composed of linear ion trap and high-resolution mass spectrometers. Gaseous agents were detected by MS or MS(2) in negative ion mode. The limits of detection for a 1 s measurement were typically at or below the microgram per cubic meter level except for chloropicrin (submilligram per cubic meter). Matrix effects by gasoline vapor resulted in minimal false-positive signals for all the CWAs and some signal suppression in the case of mustard gas. The moisture level did influence the measurement of the CWAs.

  14. Improved detection of low vapor pressure compounds in air by serial combination of single-sided membrane introduction with fiber introduction mass spectrometry (SS-MIMS-FIMS).

    PubMed

    Cotte-Rodríguez, Ismael; Handberg, Eric; Noll, Robert J; Kilgour, David P A; Cooks, R Graham

    2005-05-01

    The use of two methods in tandem, single-sided membrane introduction mass spectrometry (SS-MIMS) and fiber introduction mass spectrometry (FIMS), is presented as a technique for field analysis. The combined SS-MIMS-FIMS technique was employed in both a modified commercial mass spectrometer and a miniature mass spectrometer for the selective preconcentration of the explosive simulant o-nitrotoluene (ONT) and the chemical warfare agent simulant, methyl salicylate (MeS), in air. A home-built FIMS inlet was fabricated to allow introduction of the solid-phase microextraction (SPME) fiber into the mass spectrometer chamber and subsequent desorption of the trapped compounds using resistive heating. The SS-MIMS preconcentration system was also home-built from commercial vacuum parts. Optimization experiments were done separately for each preconcentration system to achieve the best extraction conditions prior to use of the two techniques in combination. Improved limits of detection, in the low ppb range, were observed for the combination compared to FIMS alone, using several SS-MIMS preconcentration cycles. The SS-MIMS-FIMS response for both instruments was found to be linear over the range 50 to 800 ppb. Other parameters studied were absorption time profiles, effects of sample flow rate, desorption temperature, fiber background, memory effects, and membrane fatigue. This simple, sensitive, accurate, robust, selective, and rapid sample preconcentration and introduction technique shows promise for field analysis of low vapor pressure compounds, where analyte concentrations will be extremely low and the compounds are difficult to extract from a matrix like air.

  15. Small field diode correction factors derived using an air core fibre optic scintillation dosimeter and EBT2 film.

    PubMed

    Ralston, Anna; Liu, Paul; Warrener, Kirbie; McKenzie, David; Suchowerska, Natalka

    2012-05-07

    There is no commercially available real-time dosimeter that can accurately measure output factors for field sizes down to 4 mm without the use of correction factors. Silicon diode detectors are commonly used but are not dosimetrically water equivalent, resulting in energy dependence and fluence perturbation. In contrast, plastic scintillators are nearly dosimetrically water equivalent. A fibre optic dosimeter (FOD) with a 0.8 mm(3) plastic scintillator coupled to an air core light guide was used to measure the output factors for Novalis/BrainLab stereotactic cones of diameter 4-30 mm and Novalis MLC fields of width 5-100 mm. The FOD data matched the output factors measured by a 0.125 cm(3) Semiflex ion chamber for the MLC fields above 30 mm and those measured with the EBT2 radiochromic film for the cones and MLC fields below 30 mm. Relative detector readings were obtained with four diode types (IBA SFD, EFD, PFD, PTW 60012) for the same fields. Empirical diode correction factors were determined by taking the ratio of FOD output factors to diode relative detector readings. The diodes were found to over-respond by 3%-16% for the smallest field. There was good agreement between different diodes of the same model number.

  16. The effects of air mass transport, seasonality, and meteorology on pollutant levels at the Iskrba regional background station (1996-2014)

    NASA Astrophysics Data System (ADS)

    Poberžnik, Matevž; Štrumbelj, Erik

    2016-06-01

    Our main goal was to estimate the effects of long-range air transport on pollutant concentrations measured at the Iskrba regional background station (Slovenia). We cluster back-trajectories into categories and simultaneously model the effects of meteorology, seasonality, trends, and air mass trajectory clusters using a Bayesian statistical approach. This simplifies the interpretation of results and allows us to better identify the effects of individual variables, which is important, because pollutant concentrations, meteorology, and trajectories are seasonal and correlated. Similar to related work from other European sites, we find that slow and faster moving trajectories from eastern Europe and the northern part of the Balkan peninsula are associated with higher pollutant levels, while fast-moving trajectories from the Atlantic are associated with lower pollutant concentration. Overall, pollutant concentrations have decreased in the studied period.

  17. Neurohumoral and mechanical factors in the modulation of left ventricular mass

    NASA Technical Reports Server (NTRS)

    Franklin, Eleanor I.; Hawthorne, Edward W.

    1987-01-01

    The goals for the research were to define, describe, and study those neuroendocrine and mechanical mechanisms that may play a role in the initiation and maintenance of an increase in, or cause regression of, the mass of the left ventricle. Dynamic changes in heart mass have been observed to occur in man and animals: (1) enlargement of the heart is frequently encountered in patients with hypertensive disease, and (2) decrease in heart mass has been reported for men exposed to prolonged space flight. The basic physiologic processes which may explain how these changes occur, and the effects of gain or loss of myocardial mass on cardiac performance were considered significant questions to be answered for the benefit of the National Aeronautics and Space Administration.

  18. Ambient Air Pollution, Meteorological Factors and Outpatient Visits for Eczema in Shanghai, China: A Time-Series Analysis

    PubMed Central

    Li, Qiao; Yang, Yingying; Chen, Renjie; Kan, Haidong; Song, Weimin; Tan, Jianguo; Xu, Feng; Xu, Jinhua

    2016-01-01

    Environmental irritants are important risk factors for skin diseases, but little is known about the influence of environmental factors on eczema incidence. In this time-series study, our objective was to examine the associations of environmental factors with outpatient visits for eczema. Daily outpatient visits between 2007 and 2011 (1826 days) were collected from Huashan Hospital in Shanghai, China. We used an overdispersed generalized additive model to investigate the short-term association between environmental factors and outpatient visits for eczema. Daily outpatient visits for eczema were significantly associated with air pollution and meteorological factors. For example, a 10 μg/m3 increase of 7-day (lag 06) average concentrations of PM10 (particulate matter no greater than 10 microns), SO2, NO2 was associated with 0.81% (95% confidence intervals (CI) 0.39%, 1.22%), 2.22% (95% CI: 1.27%, 3.16%) and 2.31% (95% CI: 1.17%, 3.45%) increase in outpatient visits for eczema, respectively. A 10 °C elevation of temperature on lag 0 day were associated with 8.44% (95% CI: 4.66%, 12.22%) increase in eczema visits, whereas 10 unit decrease of 7-day average relative humidity were associated with 10.86% (95% CI: 8.83%, 12.89%) increase in eczema visits. This study provided clear evidence of ambient air pollution, high temperature and low relative humidity on increasing the incidence of eczema in Shanghai, China. PMID:27834842

  19. The Use of Red Green Blue Air Mass Imagery to Investigate the Role of Stratospheric Air in a Non-convective Wind Event

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Zavodsky, B. T.; Jedlovec, G. J.; Molthan, A. L.

    2013-01-01

    Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses.

  20. Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

    PubMed Central

    Batterman, Stuart; Cook, Richard; Justin, Thomas

    2015-01-01

    Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates. PMID:25844042

  1. Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses.

    PubMed

    Batterman, Stuart; Cook, Richard; Justin, Thomas

    2015-04-01

    Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates.

  2. Temporal variation of traffic on highways and the development of accurate temporal allocation factors for air pollution analyses

    NASA Astrophysics Data System (ADS)

    Batterman, Stuart; Cook, Richard; Justin, Thomas

    2015-04-01

    Traffic activity encompasses the number, mix, speed and acceleration of vehicles on roadways. The temporal pattern and variation of traffic activity reflects vehicle use, congestion and safety issues, and it represents a major influence on emissions and concentrations of traffic-related air pollutants. Accurate characterization of vehicle flows is critical in analyzing and modeling urban and local-scale pollutants, especially in near-road environments and traffic corridors. This study describes methods to improve the characterization of temporal variation of traffic activity. Annual, monthly, daily and hourly temporal allocation factors (TAFs), which describe the expected temporal variation in traffic activity, were developed using four years of hourly traffic activity data recorded at 14 continuous counting stations across the Detroit, Michigan, U.S. region. Five sites also provided vehicle classification. TAF-based models provide a simple means to apportion annual average estimates of traffic volume to hourly estimates. The analysis shows the need to separate TAFs for total and commercial vehicles, and weekdays, Saturdays, Sundays and observed holidays. Using either site-specific or urban-wide TAFs, nearly all of the variation in historical traffic activity at the street scale could be explained; unexplained variation was attributed to adverse weather, traffic accidents and construction. The methods and results presented in this paper can improve air quality dispersion modeling of mobile sources, and can be used to evaluate and model temporal variation in ambient air quality monitoring data and exposure estimates.

  3. Simulation of heat and mass transfer processes in the experimental section of the air-condensing unit of Scientific Production Company "Turbocon"

    NASA Astrophysics Data System (ADS)

    Artemov, V. I.; Minko, K. B.; Yan'kov, G. G.; Kiryukhin, A. V.

    2016-05-01

    A mathematical model was developed to be used for numerical analysis of heat and mass transfer processes in the experimental section of the air condenser (ESAC) created in the Scientific Production Company (SPC) "Turbocon" and mounted on the territory of the All-Russia Thermal Engineering Institute. The simulations were performed using the author's CFD code ANES. The verification of the models was carried out involving the experimental data obtained in the tests of ESAC. The operational capability of the proposed models to calculate the processes in steam-air mixture and cooling air and algorithms to take into account the maldistribution in the various rows of tube bundle was shown. Data on the influence of temperature and flow rate of the cooling air on the pressure in the upper header of ESAC, effective heat transfer coefficient, steam flow distribution by tube rows, and the dimensions of the ineffectively operating zones of tube bundle for two schemes of steam-air mixture flow (one-pass and two-pass ones) were presented. It was shown that the pressure behind the turbine (in the upper header) increases significantly at increase of the steam flow rate and reduction of the flow rate of cooling air and its temperature rise, and the maximum value of heat transfer coefficient is fully determined by the flow rate of cooling air. Furthermore, the steam flow rate corresponding to the maximum value of heat transfer coefficient substantially depends on the ambient temperature. The analysis of the effectiveness of the considered schemes of internal coolant flow was carried out, which showed that the two-pass scheme is more effective because it provides lower pressure in the upper header, despite the fact that its hydraulic resistance at fixed flow rate of steam-air mixture is considerably higher than at using the one-pass schema. This result is a consequence of the fact that, in the two-pass scheme, the condensation process involves the larger internal surface of tubes

  4. Application of high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for determination of chromium compounds in the air at the workplace.

    PubMed

    Stanislawska, Magdalena; Janasik, Beata; Wasowicz, Wojciech

    2013-12-15

    The toxicity and bioavailability of chromium species are highly dependable on the form or species, therefore determination of total chromium is insufficient for a complete toxicological evaluation and risk assessment. An analytical method for determination of soluble and insoluble Cr (III) and Cr (VI) compounds in welding fume at workplace air has been developed. The total chromium (Cr) was determined by using quadruple inductively coupled plasma mass spectrometry (ICP-MS) equipped with a dynamic reaction cell (DRC(®)). Soluble trivalent and hexavalent chromium compounds were determined by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). A high-speed, reversed-phase CR C8 column (PerkinElmer, Inc., Shelton, CT, USA) was used for the speciation of soluble Cr (III) and soluble Cr (VI). The separation was accomplished by interaction of the chromium species with the different components of the mobile phase. Cr (III) formed a complex with EDTA, i.e. retained on the column, while Cr (VI) existed in the solutions as dichromate. Alkaline extraction (2% KOH and 3% Na2CO3) and anion exchange column (PRP-X100, PEEK, Hamilton) were used for the separation of the total Cr (VI). The results of the determination of Cr (VI) were confirmed by the analysis of the certified reference material BCR CRM 545 (Cr (VI) in welding dust). The results obtained for the certified material (40.2±0.6 g kg(-1)) and the values recorded in the examined samples (40.7±0.6 g kg(-1)) were highly consistent. This analytical method was applied for the determination of chromium in the samples in the workplace air collected onto glass (Whatman, Ø 37 mm) and membrane filters (Sartorius, 0.8 μm, Ø 37 mm). High performance liquid chromatography with inductively coupled plasma mass spectrometry is a remarkably powerful and versatile technique for determination of chromium species in welding fume at workplace air.

  5. Heat and mass transfer in a dissociated laminar boundary layer of air with consideration of the finite rate of chemical reaction

    NASA Technical Reports Server (NTRS)

    Oyegbesan, A. O.; Algermissen, J.

    1986-01-01

    A numerical investigation of heat and mass transfer in a dissociated laminar boundary layer of air on an isothermal flat plate is carried out for different degrees of cooling of the wall. A finite-difference chemical model is used to study elementary reactions involving NO2 and N2O. The analysis is based on equations of continuity, momentum, energy, conservation and state for the two-dimensional viscous flow of a reacting multicomponent mixtures. Attention is given to the effects of both catalyticity and noncatalyticity of the wall.

  6. Design and preliminary tests of a blade tip air mass injection system for vortex modification and possible noise reduction on a full-scale helicopter rotor

    NASA Technical Reports Server (NTRS)

    Pegg, R. J.; Hosier, R. N.; Balcerak, J. C.; Johnson, H. K.

    1975-01-01

    Full-scale tests were conducted on the Langley helicopter rotor test facility as part of a study to evaluate the effectiveness of a turbulent blade tip air mass injection system in alleviating the impulsive noise (blade slap) caused by blade-vortex interaction. Although blade-slap conditions could not be induced during these tests, qualitative results from flow visualization studies using smoke showed that the differential velocity between the jet velocity and the rotor tip speed was a primary parameter controlling the vortex modification.

  7. Determination of Hazardous Air Pollutant Surrogates Using Resonance Enhanced Multi Photon Ionization - Time of Flight Mass Spectrometry

    EPA Science Inventory

    EPA?s preferred approach for regulatory emissions compliance is based upon real-time monitoring of individual hazardous air pollutants (HAPs). Real-time, continuous monitoring not only provides the most comprehensive assurance of emissions compliance, but also can serve as a pro...

  8. Monitoring of Hazardous Air Pollutant Surrogates Using Resonance Enhanced Multiphoton Ionization/Time of Flight Mass Spectrometry

    EPA Science Inventory

    EPA’s preferred approach for regulatory emissions compliance is based upon real-time monitoring of individual hazardous air pollutants (HAPs). Real-time, continuous monitoring not only provides the most comprehensive assurance of emissions compliance, but also can serve as...

  9. The Environmental Factor: Driving the Onset and Early Evolution of High-Mass Stars and Clusters

    NASA Astrophysics Data System (ADS)

    Rivera-Ingraham, Alana; Marston, Anthony; Martin, Peter; Ristorcelli, Isabelle; Juvela, Mika

    2015-08-01

    While the process leading to the formation of low-mass stars is reasonably well established, the origin of their high-mass counterparts, and in particular, the link with the properties and evolution of the parental structures, remains poorly understood. The key role that high-mass stars and massive clusters play in driving the evolution of the ISM, from planetary to galactic scales, makes this study, however, particularly critical.Here we present the latest results from an ongoing Herschel-based project of high-mass star formation in the Outer Galaxy, and which aims to quantify the complex dependence between the final characteristics of young high-mass stars and the early evolution of their local environment.Datasets from the Herschel imaging survey of OB Young Stellar objects (HOBYS; PI. F. Motte) and the Herschel infrared Galactic Plane Survey (Hi-Gal; PI. S. Molinari) Key Programmes are used as a base to carry out an in-depth examination of the cloud physical characteristics, compact source population, and star formation history of those regions with the potential for (and on-going) high-mass star and cluster formation. Results from this study are compelling evidence for the requirement of local external processes, such as stellar feedback (e.g., Convergent Constructive Feedback model; Rivera-Ingraham et al. 2013), in order to counteract the limitations of gravity in the formation and evolution of dense and exotic environments. We will describe how such processes could drive the formation and evolution of the parental host, and therefore influence the final characteristics of the young high-mass stars and clusters (Rivera-Ingraham, et al. 2015a; 2015b, in prep). Our conclusions are further supported by an extensive independent analysis of filamentary properties as a function of Galactic environment (Rivera-Ingraham et al. 2015c; subm), and which we will present as part of the Galactic Cold Cores Key Programme (PI. M. Juvela).

  10. Inter-annual variability of air mass and acidified pollutants transboundary exchange in the north-eastern part of the EANET region

    NASA Astrophysics Data System (ADS)

    Gromov, Sergey A.; Trifonova-Yakovleva, Alisa; Gromov, Sergey S.

    2016-04-01

    Anthropogenic emissions, be it exhaust gases or aerosols, stem from multitude of sources and may survive long-range transport within the air masses they were emitted into. So they follow regional and global transport pathways varying under different climatological regimes. Transboundary transfer of pollutants occurs this way and has a significant impact on the ecological situation of the territories neighbouring those of emission sources, as found in a few earlier studies examining the environmental monitoring data [1]. In this study, we employ a relatively facile though robust technique for estimating the transboundary air and concomitant pollutant fluxes us