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Sample records for air kerma levels

  1. Evaluation of entrance surface air kerma in pediatric chest radiography

    NASA Astrophysics Data System (ADS)

    Porto, L.; Lunelli, N.; Paschuk, S.; Oliveira, A.; Ferreira, J. L.; Schelin, H.; Miguel, C.; Denyak, V.; Kmiecik, C.; Tilly, J.; Khoury, H.

    2014-11-01

    The objective of this study was to evaluate the entrance surface air kerma in pediatric chest radiography. An evaluation of 301 radiographical examinations in anterior-posterior (AP) and posterior-anterior (PA) (166 examinations) and lateral (LAT) (135 examinations) projections was performed. The analyses were performed on patients grouped by age; the groups included ages 0-1 y, 1-5 y, 5-10 y, and 10-15 y. The entrance surface air kerma was determined with DoseCal software (Radiological Protection Center of Saint George's Hospital, London) and thermoluminescent dosimeters. Two different exposure techniques were compared. The doses received by patients who had undergone LAT examinations were 40% higher, on average, those in AP/PA examinations because of the difference in tube voltage. A large high-dose “tail” was observed for children up to 5 y old. An increase in tube potential and corresponding decrease in current lead to a significant dose reduction. The difference between the average dose values for different age ranges was not practically observed, implying that the exposure techniques are still not optimal. Exposure doses received using the higher tube voltage and lower current-time product correspond to the international diagnostic reference levels.

  2. Air kerma based dosimetry calibration for the Leksell Gamma Knife

    SciTech Connect

    Meltsner, Sheridan Griffin; DeWerd, Larry A.

    2009-02-15

    No accepted official protocol exists for the dosimetry of the Leksell Gamma Knife registered (GK) stereotactic radiosurgery device. Establishment of a dosimetry protocol has been complicated by the unique partial-hemisphere arrangement of 201 individual {sup 60}Co beams simultaneously focused on the treatment volume and by the rigid geometry of the GK unit itself. This article proposes an air kerma based dosimetry protocol using either an in-air or in-acrylic phantom measurement to determine the absorbed dose rate of fields of the 18 mm helmet of a GK unit. A small-volume air ionization chamber was used to make measurements at the physical isocenter of three GK units. The absorbed dose rate to water was determined using a modified version of the AAPM Task Group 21 protocol designed for use with {sup 60}Co-based teletherapy machines. This experimentally determined absorbed dose rate was compared to the treatment planning system (TPS) absorbed dose rate. The TPS used with the GK unit is Leksell GammaPlan. The TPS absorbed dose rate at the time of treatment is the absorbed dose rate determined by the physicist at the time of machine commissioning decay corrected to the treatment date. The TPS absorbed dose rate is defined as absorbed dose rate to water at the isocenter of a water phantom with a radius of 8 cm. Measurements were performed on model B and C Gamma Knife units. The absorbed dose rate to water for the 18 mm helmet determined using air-kerma based calculations is consistently between 1.5% and 2.9% higher than the absorbed dose rate provided by the TPS. These air kerma based measurements allow GK dosimetry to be performed with an established dosimetry protocol and without complications arising from the use of and possible variations in solid phantom material. Measurements were also made with the same ionization chamber in a spherical acrylic phantom for comparison. This methodology will allow further development of calibration methods appropriate for the

  3. Comparison of the NIST and ENEA air kerma standards

    SciTech Connect

    Laitano, R.F.; Toni, M.P.; Lamperti, P.J.

    1998-07-01

    A comparison was made between the National Institute of Standards and Technology (NIST) and Ente per le Nuov Tecnologie l`Energia e l`Ambiente (ENEA) air kerma standards for medium energy x rays and {sup 60}Co gamma rays. The comparison took place at ENEA in June 1994. Two different transfer chambers from NIST were used for the comparison. The measurements were made at radiation qualities similar to those used at the Bureau International des Poids et Mesures (BIPM) (generating voltages of 100 kV, 135 kV, 180 kV and 250 kV, respectively) and with {sup 60}Co gamma radiation. The transfer chamber calibration factors obtained at the NIST and at the ENEA agreed with one another to 0.03% for {sup 60}Co gamma radiation and between 0.1% to 0.8% for the medium energy x-ray beam codes.

  4. Air kerma and absorbed dose standards for reference dosimetry in brachytherapy

    PubMed Central

    2014-01-01

    This article reviews recent developments in primary standards for the calibration of brachytherapy sources, with an emphasis on the currently most common photon-emitting radionuclides. The introduction discusses the need for reference dosimetry in brachytherapy in general. The following section focuses on the three main quantities, i.e. reference air kerma rate, air kerma strength and absorbed dose rate to water, which are currently used for the specification of brachytherapy photon sources and which can be realized with primary standards from first principles. An overview of different air kerma and absorbed dose standards, which have been independently developed by various national metrology institutes over the past two decades, is given in the next two sections. Other dosimetry techniques for brachytherapy will also be discussed. The review closes with an outlook on a possible transition from air kerma to absorbed dose to water-based calibrations for brachytherapy sources in the future. PMID:24814696

  5. The IPEM code of practice for determination of the reference air kerma rate for HDR (192)Ir brachytherapy sources based on the NPL air kerma standard.

    PubMed

    Bidmead, A M; Sander, T; Locks, S M; Lee, C D; Aird, E G A; Nutbrown, R F; Flynn, A

    2010-06-07

    This paper contains the recommendations of the high dose rate (HDR) brachytherapy working party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a Code of Practice (COP) for the UK for measuring the reference air kerma rate (RAKR) of HDR (192)Ir brachytherapy sources. In 2004, the National Physical Laboratory (NPL) commissioned a primary standard for the realization of RAKR of HDR (192)Ir brachytherapy sources. This has meant that it is now possible to calibrate ionization chambers directly traceable to an air kerma standard using an (192)Ir source (Sander and Nutbrown 2006 NPL Report DQL-RD 004 (Teddington: NPL) http://publications.npl.co.uk). In order to use the source specification in terms of either RAKR, Κ(R) (ICRU 1985 ICRU Report No 38 (Washington, DC: ICRU); ICRU 1997 ICRU Report No 58 (Bethesda, MD: ICRU)), or air kerma strength, S(K) (Nath et al 1995 Med. Phys. 22 209-34), it has been necessary to develop algorithms that can calculate the dose at any point around brachytherapy sources within the patient tissues. The AAPM TG-43 protocol (Nath et al 1995 Med. Phys. 22 209-34) and the 2004 update TG-43U1 (Rivard et al 2004 Med. Phys. 31 633-74) have been developed more fully than any other protocol and are widely used in commercial treatment planning systems. Since the TG-43 formalism uses the quantity air kerma strength, whereas this COP uses RAKR, a unit conversion from RAKR to air kerma strength was included in the appendix to this COP. It is recommended that the measured RAKR determined with a calibrated well chamber traceable to the NPL (192)Ir primary standard is used in the treatment planning system. The measurement uncertainty in the source calibration based on the system described in this COP has been reduced considerably compared to other methods based on interpolation techniques.

  6. New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources.

    PubMed

    Seltzer, Stephen M; O'Brien, Michelle; Mitch, Michael G

    2014-01-01

    The new primary standard for low-energy electronic brachytherapy sources for the United States is described. These miniature x-ray tubes are inserted in catheters for interstitial radiation therapy and operate at tube potentials of up to about 50 kV. The standard is based on the realization of the air kerma produced by the x-ray beam at a reference distance in air of 50 cm.

  7. New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources

    PubMed Central

    Seltzer, Stephen M; O’Brien, Michelle; Mitch, Michael G

    2014-01-01

    The new primary standard for low-energy electronic brachytherapy sources for the United States is described. These miniature x-ray tubes are inserted in catheters for interstitial radiation therapy and operate at tube potentials of up to about 50 kV. The standard is based on the realization of the air kerma produced by the x-ray beam at a reference distance in air of 50 cm. PMID:26601044

  8. New National Air-Kerma-Strength Standards for (125)I and (103)Pd Brachytherapy Seeds.

    PubMed

    Seltzer, Stephen M; Lamperti, Paul J; Loevinger, Robert; Mitch, Michael G; Weaver, James T; Coursey, Bert M

    2003-01-01

    The new U.S. measurement standard for the air-kerma strength from low-energy photon-emitting brachytherapy seed sources is formally described in detail. This instrument-based standard was implemented on 1 January 1999, with its salient features and the implications of differences with the previous standard given only through a series of informal communications. The Wide-Angle Free-Air Chamber (WAFAC) is specially designed to realize air kerma from a single-seed source emitting photons with energies up to about 40 keV, and is now used to measure the wide variety of seeds used in prostate-cancer therapy that has appeared in the last few years. For the two (125)I seed models that have been subject to both the old and new standards, the new standard reduces the air-kerma strength by 10.3 %. This change is mainly due to the removal of the influence on the measurement of the Ti K x rays produced in the source encapsulation, a component with no clinical significance.

  9. Effects of aluminum-copper alloy filtration on photon spectra, air kerma rate and image contrast.

    PubMed

    Gonçalves, Andréa; Rollo, João Manuel Domingos de Almeida; Gonçalves, Marcelo; Haiter Neto, Francisco; Bóscolo, Frab Norberto

    2004-01-01

    This study evaluated the performance of aluminum-copper alloy filtration, without the original aluminum filter, for dental radiography in terms of x-ray energy spectrum, air kerma rate and image quality. Comparisons of various thicknesses of aluminum-copper alloy in three different percentages were made with aluminum filtration. Tests were conducted on an intra-oral dental x-ray machine and were made on mandible phantom and on step-wedge. Depending on the thickness of aluminum-copper alloy filtration, the beam could be hardened and filtrated. The use of the aluminum-copper alloy filter resulted in reductions in air kerma rate from 8.40% to 47.33%, and indicated the same image contrast when compared to aluminum filtration. Aluminum-copper alloy filtration may be considered a good alternative to aluminum filtration.

  10. Integration of kerma-area product and cumulative air kerma determination into a skin dose tracking system for fluoroscopic imaging procedures

    NASA Astrophysics Data System (ADS)

    Vijayan, Sarath; Shankar, Alok; Rudin, Stephen; Bednarek, Daniel R.

    2016-03-01

    The skin dose tracking system (DTS) that we developed provides a color-coded mapping of the cumulative skin dose distribution on a 3D graphic of the patient during fluoroscopic procedures in real time. The DTS has now been modified to also calculate the kerma area product (KAP) and cumulative air kerma (CAK) for fluoroscopic interventions using data obtained in real-time from the digital bus on a Toshiba Infinix system. KAP is the integral of air kerma over the beam area and is typically measured with a large-area transmission ionization chamber incorporated into the collimator assembly. In this software, KAP is automatically determined for each x-ray pulse as the product of the air kerma/ mAs from a calibration file for the given kVp and beam filtration times the mAs per pulse times the length and width of the beam times a field nonuniformity correction factor. Field nonuniformity is primarily the result of the heel effect and the correction factor was determined from the beam profile measured using radio-chromic film. Dividing the KAP by the beam area at the interventional reference point provides the area averaged CAK. The KAP and CAK per x-ray pulse are summed after each pulse to obtain the total procedure values in real-time. The calculated KAP and CAK were compared to the values displayed by the fluoroscopy machine with excellent agreement. The DTS now is able to automatically calculate both KAP and CAK without the need for measurement by an add-on transmission ionization chamber.

  11. 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.

  12. Air-over-ground calculations of the neutron, prompt, and secondary-gamma free-in-air tissue kerma from the Hiroshima and Nagasaki devices

    SciTech Connect

    Pace, J.V. III; Knight, J.R.; Bartine, D.E.

    1982-01-01

    This paper reports preliminary results of the two-dimensional discrete-ordinate, calculations for the air-over-ground transport of radiation from the Hiroshima and Nagasaki weapon devices. It was found that the gamma-ray kerma dominated the total kerma for both environments.

  13. Air-kerma strength determination of a miniature x-ray source for brachytherapy applications

    NASA Astrophysics Data System (ADS)

    Davis, Stephen D.

    A miniature x-ray source has been developed by Xoft Inc. for high dose-rate brachytherapy treatments. The source is contained in a 5.4 mm diameter water-cooling catheter. The source voltage can be adjusted from 40 kV to 50 kV and the beam current is adjustable up to 300 muA. Electrons are accelerated toward a tungsten-coated anode to produce a lightly-filtered bremsstrahlung photon spectrum. The sources were initially used for early-stage breast cancer treatment using a balloon applicator. More recently, Xoft Inc. has developed vaginal and surface applicators. The miniature x-ray sources have been characterized using a modification of the American Association of Physicists in Medicine Task Group No. 43 formalism normally used for radioactive brachytherapy sources. Primary measurements of air kerma were performed using free-air ionization chambers at the University of Wisconsin (UW) and the National Institute of Standards and Technology (NIST). The measurements at UW were used to calibrate a well-type ionization chamber for clinical verification of source strength. Accurate knowledge of the emitted photon spectrum was necessary to calculate the corrections required to determine air-kerma strength, defined in vacuo. Theoretical predictions of the photon spectrum were calculated using three separate Monte Carlo codes: MCNP5, EGSnrc, and PENELOPE. Each code used different implementations of the underlying radiological physics. Benchmark studies were performed to investigate these differences in detail. The most important variation among the codes was found to be the calculation of fluorescence photon production following electron-induced vacancies in the L shell of tungsten atoms. The low-energy tungsten L-shell fluorescence photons have little clinical significance at the treatment distance, but could have a large impact on air-kerma measurements. Calculated photon spectra were compared to spectra measured with high-purity germanium spectroscopy systems at both UW and

  14. MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness

    SciTech Connect

    DeLorenzo, M; Wu, D; Rutel, I; Yang, K

    2015-06-15

    Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation

  15. Primary Beam Air Kerma Dependence on Distance from Cargo and People Scanners

    SciTech Connect

    Strom, Daniel J.; Cerra, Frank

    2016-01-01

    The distance dependence of air kerma or dose rate of the primary radiation beam is not obvious for security scanners of cargo and people in which there is relative motion between a collimated source and the person or object being imaged. To study this problem, one fixed line source and three moving-source scan-geometry cases are considered, each characterized by radiation emanating perpendicular to an axis. The cases are 1) a stationary line source of radioactive material, e.g., contaminated solution in a pipe; 2) a moving, uncollimated point source of radiation that is shuttered or off when it is stationary; 3) a moving, collimated point source of radiation that is shuttered or off when it is stationary; and 4) a translating, narrow “pencil” beam emanating in a flying-spot, raster pattern. Each case is considered for short and long distances compared to the line source length or path traversed by a moving source. The short distance model pertains mostly to dose to objects being scanned and personnel associated with the screening operation. The long distance model pertains mostly to potential dose to bystanders. For radionuclide sources, the number of nuclear transitions that occur a) per unit length of a line source, or b) during the traversal of a point source, is a unifying concept. The “universal source strength” of air kerma rate at a meter from the source can be used to describe x-ray machine or radionuclide sources. For many cargo and people scanners with highly collimated fan or pencil beams, dose varies as the inverse of the distance from the source in the near field and with the inverse square of the distance beyond a critical radius. Ignoring the inverse square dependence and using inverse distance dependence is conservative in the sense of tending to overestimate dose.

  16. Comparison of the NIST and BIPM Standards for Air Kerma in Medium-Energy X-Rays.

    PubMed

    Burns, D T; O'Brien, M

    2006-01-01

    A comparison has been made of the air-kerma standards for medium-energy x-rays of the National Institute of Standards and Technology (NIST) and the Bureau International des Poids et Mesures (BIPM). The comparison involved a series of measurements at the BIPM and the NIST using the air-kerma standards and three NIST reference-class transfer ionization chamber standards. Reference beam qualities in the range from 100 kV to 250 kV were used. The results show the standards to be in reasonable agreement within the combined standard uncertainty of the comparison of 0.37 %, although a significant trend with radiation quality is observed and the possible sources discussed.

  17. Key comparison BIPM.RI(I)-K5 of the air kerma standards of the VSL and the BIPM in 137Cs gamma radiation

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Burns, D. T.; Jansen, B. J.; de Pooter, J. A.

    2016-01-01

    A direct comparison of the standards for air kerma of the VSL, Netherlands, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 137Cs radiation beam of the BIPM in April 2016. The comparison result, evaluated as a ratio of the VSL and the BIPM standards for air kerma, is 0.9952 with a combined standard uncertainty of 3.8 × 10-3. The results for an indirect comparison made at the same time are consistent with the direct results at the level of 1 part in 104. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  18. Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the SCK.CEN, Belgium and the BIPM in 60Co gamma radiation

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Burns, D.; Mihailescu, L. C.; Chiriotti, S.

    2017-01-01

    A first key comparison of the standards for air kerma of the Laboratory for Nuclear Calibrations (LNK) from the Studiecentrum voor Kernenergie—Centre d'Etude de l'Energie Nucleaire (SCK.CEN), Belgium and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in September 2016. The comparison result, evaluated as a ratio of the SCK.CEN and the BIPM standards for air kerma, is 1.0021 with a combined standard uncertainty of 2.6 × 10-3. The results for an indirect comparison made at the same time are consistent with the direct results at the level of 7 parts in 104. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  19. APMP key comparison for the measurement of air kerma for 60Co (APMP.RI(I)-K1.1)

    NASA Astrophysics Data System (ADS)

    Webb, D. V.; Lee, J.-H.; Budiantari, C. T.; Laban, J.; Saito, N.; Srimanoroth, S.; Khaled, N. E.

    2016-01-01

    The results are reported for an APMP.R(I)-K1.1 comparison that extends the regional comparison of standards for air kerma APMP.R(I)-K1 to several laboratories unable to participate earlier. The comparison was conducted with the goal of supporting the relevant calibration and measurement capabilities (CMCs) planned for publication by the participant laboratories. The comparison was conducted by the pilot laboratory, the Australian Radiation Protection and Nuclear Safety (ARPANSA), Australia, supported by the Institute of Nuclear Energy Research (INER), Taiwan, in a modified ring-shaped arrangement from September 2009 to November 2010, in parallel with an APMP.R(I)-K4 comparison being piloted by the INER. The laboratories that took part in the comparison were the ARPANSA, the Centre of Technology of Radiation Safety and Metrology (PTKMR-BATAN), Indonesia, the Division of Radiation and Medical Devices (DMSC), Thailand, the INER, the National Centre for Radiation Science (NCRS), New Zealand, the National Institute for Standards (NIS), Egypt and the National Metrology Institute of Japan (NMIJ/AIST), Japan. The two primary laboratories, ARPANSA and NMIJ, were chosen as the linking laboratories. Three ionization chambers were used as transfer instruments to be calibrated in terms of air kerma in 60Co radiotherapy beams. The comparison result is based on the ratio between the air kerma calibration coefficients (NK) determined by the participants and the mean of the results of the linking laboratories. The mean comparison ratio was found to be within 0.5 % of the key comparison reference value KCRV. The largest deviation between any two comparison ratios for the three chambers in terms of air kerma was 2.0 %. An analysis of the participant uncertainty budgets enabled the calculation of degrees of equivalence (DoE) in terms of the deviations of the results and their associated uncertainties. As a result of this APMP comparison, the BIPM key comparison database (KCDB) should

  20. MO-D-BRD-04: NIST Air-Kerma Standard for Electronic Brachytherapy Calibrations

    SciTech Connect

    Mitch, M.

    2015-06-15

    Electronic brachytherapy (eBT) has seen an insurgence of manufacturers entering the US market for use in radiation therapy. In addition to the established interstitial, intraluminary, and intracavitary applications of eBT, many centers are now using eBT to treat skin lesions. It is important for medical physicists working with electronic brachytherapy sources to understand the basic physics principles of the sources themselves as well as the variety of applications for which they are being used. The calibration of the sources is different from vendor to vendor and the traceability of calibrations has evolved as new sources came to market. In 2014, a new air-kerma based standard was introduced by the National Institute of Standards and Technology (NIST) to measure the output of an eBT source. Eventually commercial treatment planning systems should accommodate this new standard and provide NIST traceability to the end user. The calibration and commissioning of an eBT system is unique to its application and typically entails a list of procedural recommendations by the manufacturer. Commissioning measurements are performed using a variety of methods, some of which are modifications of existing AAPM Task Group protocols. A medical physicist should be familiar with the different AAPM Task Group recommendations for applicability to eBT and how to properly adapt them to their needs. In addition to the physical characteristics of an eBT source, the photon energy is substantially lower than from HDR Ir-192 sources. Consequently, tissue-specific dosimetry and radiobiological considerations are necessary when comparing these brachytherapy modalities and when making clinical decisions as a radiation therapy team. In this session, the physical characteristics and calibration methodologies of eBt sources will be presented as well as radiobiology considerations and other important clinical considerations. Learning Objectives: To understand the basic principles of electronic

  1. Comparison of the NIST and PTB Air-Kerma Standards for Low-Energy X-Rays.

    PubMed

    O'Brien, Michelle; Bueermann, Ludwig

    2009-01-01

    A comparison has been made of the air-kerma standards for low-energy x rays at the National Institute of Standards and Technology (NIST) and the Physikalisch-Technische Bundesanstalt (PTB). The comparison involved a series of measurements at the PTB and the NIST using the air-kerma standards and two NIST reference-class transfer ionization chamber standards. Results are presented for the reference radiation beam qualities in the range from 25 kV to 50 kV for low energy x rays, including the techniques used for mammography dose traceability. The tungsten generated reference radiation qualities, between 25 kV and 50 kV used for this comparison, are new to NIST; therefore this comparison will serve as the preliminary comparison for NIST and a verification of the primary standard correction factors. The mammography comparison will repeat two previously unpublished comparisons between PTB and NIST. The results show the standards to be in reasonable agreement within the standard uncertainty of the comparison of about 0.4 %.

  2. Air-kerma strength determination of a new directional {sup 103}Pd source

    SciTech Connect

    Aima, Manik Reed, Joshua L.; DeWerd, Larry A.; Culberson, Wesley S.

    2015-12-15

    Purpose: A new directional {sup 103}Pd planar source array called a CivaSheet™ has been developed by CivaTech Oncology, Inc., for potential use in low-dose-rate (LDR) brachytherapy treatments. The array consists of multiple individual polymer capsules called CivaDots, containing {sup 103}Pd and a gold shield that attenuates the radiation on one side, thus defining a hot and cold side. This novel source requires new methods to establish a source strength metric. The presence of gold material in such close proximity to the active {sup 103}Pd region causes the source spectrum to be significantly different than the energy spectra of seeds normally used in LDR brachytherapy treatments. In this investigation, the authors perform air-kerma strength (S{sub K}) measurements, develop new correction factors for these measurements based on an experimentally verified energy spectrum, and test the robustness of transferring S{sub K} to a well-type ionization chamber. Methods: S{sub K} measurements were performed with the variable-aperture free-air chamber (VAFAC) at the University of Wisconsin Medical Radiation Research Center. Subsequent measurements were then performed in a well-type ionization chamber. To realize the quantity S{sub K} from a directional source with gold material present, new methods and correction factors were considered. Updated correction factors were calculated using the MCNP 6 Monte Carlo code in order to determine S{sub K} with the presence of gold fluorescent energy lines. In addition to S{sub K} measurements, a low-energy high-purity germanium (HPGe) detector was used to experimentally verify the calculated spectrum, a sodium iodide (NaI) scintillating counter was used to verify the azimuthal and polar anisotropy, and a well-type ionization chamber was used to test the feasibility of disseminating S{sub K} values for a directional source within a cylindrically symmetric measurement volume. Results: The UW VAFAC was successfully used to measure the S

  3. Comparison of the NIST and NPL Air Kerma Standards Used for X-Ray Measurements Between 10 kV and 80 kV.

    PubMed

    O'Brien, M; Lamperti, P; Williams, T; Sander, T

    2000-01-01

    A direct comparison was made between the air kerma primary standards used for the measurements of low-energy x rays at the National Institute of Standards and Technology (NIST) and the National Physical Laboratory (NPL). The comparison was conducted at the NPL using NPL reference radiation qualities between 10 kV and 80 kV. The results show the primary air-kerma standards to agree within 0.6 % of their values for beam qualities up to 80 kV.

  4. Influence of photon energy spectra from brachytherapy sources on Monte Carlo simulations of kerma and dose rates in water and air

    SciTech Connect

    Rivard, Mark J.; Granero, Domingo; Perez-Calatayud, Jose; Ballester, Facundo

    2010-02-15

    Purpose: For a given radionuclide, there are several photon spectrum choices available to dosimetry investigators for simulating the radiation emissions from brachytherapy sources. This study examines the dosimetric influence of selecting the spectra for {sup 192}Ir, {sup 125}I, and {sup 103}Pd on the final estimations of kerma and dose. Methods: For {sup 192}Ir, {sup 125}I, and {sup 103}Pd, the authors considered from two to five published spectra. Spherical sources approximating common brachytherapy sources were assessed. Kerma and dose results from GEANT4, MCNP5, and PENELOPE-2008 were compared for water and air. The dosimetric influence of {sup 192}Ir, {sup 125}I, and {sup 103}Pd spectral choice was determined. Results: For the spectra considered, there were no statistically significant differences between kerma or dose results based on Monte Carlo code choice when using the same spectrum. Water-kerma differences of about 2%, 2%, and 0.7% were observed due to spectrum choice for {sup 192}Ir, {sup 125}I, and {sup 103}Pd, respectively (independent of radial distance), when accounting for photon yield per Bq. Similar differences were observed for air-kerma rate. However, their ratio (as used in the dose-rate constant) did not significantly change when the various photon spectra were selected because the differences compensated each other when dividing dose rate by air-kerma strength. Conclusions: Given the standardization of radionuclide data available from the National Nuclear Data Center (NNDC) and the rigorous infrastructure for performing and maintaining the data set evaluations, NNDC spectra are suggested for brachytherapy simulations in medical physics applications.

  5. Dosimetric characteristics, air-kerma strength calibration and verification of Monte Carlo simulation for a new ytterbium-169 brachytherapy source

    SciTech Connect

    Perera, H.; Williamson, J.F.; Li, Zuofeng; Mishra, V.; Meigooni, A.S. )

    1994-03-01

    Ytterbium-169 ([sup 169]Yb) is a promising new isotope for brachytherapy with a half life of 32 days and an average photon energy of 93 KeV. It has an Ir-192-equivalent dose distribution in water but a much smaller half-value layer in lead (0.2 mm), affording improved radiation protection and customized shielding of dose-limiting anatomic structures. The goals of this study are to: (a) experimentally validate Monte Carlo photon transport dose-rate calculations for this energy range, (b) to develop a secondary air-kerma strength standard for [sup 169]Yb, and (c) to present essential treatment planning data including the transverse-axis dose-rate distribution and dose correction factors for a number of local shielding materials. Several interstitial [sup 169]Yb sources (type 6) and an experimental high dose-rate source were made available for this study. Monte Carlo photon-transport (MCPT) simulations, based upon validated geometric models of source structure, were used to calculate dose rates in water. To verify MCPT predictions, the transverse-axis dose distribution in homogeneous water medium was measured using a silicon-diode detector. For use in designing shielded applicators, heterogeneity correction factors (HCF) arising from small cylindrical heterogeneities of lead, aluminum, titanium, steel and air were measured in a water medium. Finally, to provide a sound experimental basis for comparing experimental and theoretical dose-rate distributions, the air-kerma strength of the sources was measured using a calibrated ion chamber. To eliminate the influence of measurement artifacts on the comparison of theory and measurement, simulated detector readings were compared directly to measured diode readings. The final data are presented in the format endorsed by the Interstitial Collaborative Working Group. 33 refs., 8 figs., 3 tabs.

  6. Poster — Thur Eve — 24: Commissioning and preliminary measurements using an Attix-style free air ionization chamber for air kerma measurements on the BioMedical Imaging and Therapy beamlines at the Canadian Light Source

    SciTech Connect

    Anderson, D; McEwen, M; Shen, H; Siegbahn, EA; Fallone, BG; Warkentin, B

    2014-08-15

    Synchrotron facilities, including the Canadian Light Source (CLS), provide opportunities for the development of novel imaging and therapy applications. A vital step progressing these applications toward clinical trials is the availability of accurate dosimetry. In this study, a refurbished Attix-style (cylindrical) free air chamber (FAC) is tested and used for preliminary air kerma measurements on the two BioMedical Imaging and Therapy (BMIT) beamlines at the CLS. The FAC consists of a telescoping chamber that relies on a difference measurement of collected charge in expanded and collapsed configurations. At the National Research Council's X-ray facility, a Victoreen Model 480 FAC was benchmarked against two primary standard FACs. The results indicated an absolute accuracy at the 0.5% level for energies between 60 and 150 kVp. A series of measurements were conducted on the small, non-uniform X-ray beams of the 05B1-1 (∼8 – 100 keV) and 05ID-2 (∼20 – 200 keV) beamlines for a variety of energies, filtrations and beam sizes. For the 05B1-1 beam with 1.1 mm of Cu filtration, recombination corrections of less than 5 % could only be achieved for field sizes no greater than 0.5 mm × 0.6 mm (corresponding to an air kerma rate of ∼ 57 Gy/min). Ionic recombination thus presents a significant challenge to obtaining accurate air kerma rate measurements using this FAC in these high intensity beams. Future work includes measurements using a smaller aperture to sample a smaller and thus more uniform beam area, as well as experimental and Monte Carlo-based investigation of correction factors.

  7. Measurement of air kerma rates for 6- to 7-MeV high-energy gamma-ray field by ionisation chamber and build-up plate.

    PubMed

    Kowatari, Munehiko; Tanimura, Yoshihiko; Tsutsumi, Masahiro

    2014-12-01

    The 6- to 7-MeV high-energy gamma-ray calibration field by the (19)F(p, αγ)(16)O reaction is to be served at the Japan Atomic Energy Agency. For the determination of air kerma rates using an ionisation chamber in the 6- to 7-MeV high-energy gamma-ray field, the establishment of the charged particle equilibrium must be achieved during measurement. In addition to measurement of air kerma rates by the ionisation chamber with a thick build-up cap, measurement using the ionisation chamber and a build-up plate (BUP) was attempted, in order to directly determine air kerma rates under the condition of regular calibration for ordinary survey meters and personal dosemeters. Before measurements, Monte Carlo calculations were made to find the optimum arrangement of BUP in front of the ionisation chamber so that the charged particle equilibrium could be well established. Measured results imply that air kerma rates for the 6- to 7-MeV high-energy gamma-ray field could be directly determined under the appropriate condition using an ionisation chamber coupled with build-up materials.

  8. SU-E-P-15: Technique Factor Modulation and Reference Plane Air Kerma Rates in Response to Simulated Patient Thickness Variations for a Sample of Current Generation Fluoroscopes

    SciTech Connect

    Wunderle, K; Rakowski, J; Dong, F

    2015-06-15

    Purpose: To evaluate and compare approaches to technique factor modulation and air kerma rates in response to simulated patient thickness variations for four state-of-the-art and one previous-generation interventional fluoroscopes. Methods: A polymethyl methacrylate (PMMA) phantom was used as a tissue surrogate for the purposes of determining fluoroscopic reference plane air kerma rates, kVp, mA, and spectral filtration over a wide range of simulated tissue thicknesses. Data were acquired for each fluoroscopic and acquisition dose curve within a default abdomen or body imaging protocol. Results: The data obtained indicated vendor- and model-specific variations in the approach to technique factor modulation and reference plane air kerma rates across a range of tissue thicknesses. Some vendors have made hardware advances increasing the radiation output capabilities of their fluoroscopes; this was evident in the acquisition air kerma rates. However, in the imaging protocol evaluated, all of the state-of-the-art systems had relatively low air kerma rates in the fluoroscopic low-dose imaging mode as compared to the previous-generation unit. Each of the newest-generation systems also employ copper filtration in the selected protocol in the acquisition mode of imaging; this is a substantial benefit, reducing the skin entrance dose to the patient in the highest dose-rate mode of fluoroscope operation. Conclusion: Understanding how fluoroscopic technique factors are modulated provides insight into the vendor-specific image acquisition approach and provides opportunities to optimize the imaging protocols for clinical practice. The enhanced radiation output capabilities of some of the fluoroscopes may, under specific conditions, may be beneficial; however, these higher output capabilities also have the potential to lead to unnecessarily high dose rates. Therefore, all parties involved in imaging, including the clinical team, medical physicists, and imaging vendors, must work

  9. Reference dosimetry at the Australian Synchrotron's imaging and medical beamline using free-air ionization chamber measurements and theoretical predictions of air kerma rate and half value layer

    SciTech Connect

    Crosbie, Jeffrey C.; Rogers, Peter A. W.; Stevenson, Andrew W.; Hall, Christopher J.; Lye, Jessica E.; Nordstroem, Terese; Midgley, Stewart M.; Lewis, Robert A.

    2013-06-15

    Purpose: Novel, preclinical radiotherapy modalities are being developed at synchrotrons around the world, most notably stereotactic synchrotron radiation therapy and microbeam radiotherapy at the European Synchrotron Radiation Facility in Grenoble, France. The imaging and medical beamline (IMBL) at the Australian Synchrotron has recently become available for preclinical radiotherapy and imaging research with clinical trials, a distinct possibility in the coming years. The aim of this present study was to accurately characterize the synchrotron-generated x-ray beam for the purposes of air kerma-based absolute dosimetry. Methods: The authors used a theoretical model of the energy spectrum from the wiggler source and validated this model by comparing the transmission through copper absorbers (0.1-3.0 mm) against real measurements conducted at the beamline. The authors used a low energy free air ionization chamber (LEFAC) from the Australian Radiation Protection and Nuclear Safety Agency and a commercially available free air chamber (ADC-105) for the measurements. The dimensions of these two chambers are different from one another requiring careful consideration of correction factors. Results: Measured and calculated half value layer (HVL) and air kerma rates differed by less than 3% for the LEFAC when the ion chamber readings were corrected for electron energy loss and ion recombination. The agreement between measured and predicted air kerma rates was less satisfactory for the ADC-105 chamber, however. The LEFAC and ADC measurements produced a first half value layer of 0.405 {+-} 0.015 and 0.412 {+-} 0.016 mm Cu, respectively, compared to the theoretical prediction of 0.427 {+-} 0.012 mm Cu. The theoretical model based upon a spectrum calculator derived a mean beam energy of 61.4 keV with a first half value layer of approximately 30 mm in water. Conclusions: The authors showed in this study their ability to verify the predicted air kerma rate and x-ray attenuation

  10. Determination of air-kerma strength for the {sup 192}Ir GammaMedplus iX pulsed-dose-rate brachytherapy source

    SciTech Connect

    Riley, A. D.; Pike, T. L.; Micka, J. A.; Fulkerson, R. K.; DeWerd, L. A.

    2013-07-15

    Purpose: Pulsed-dose-rate (PDR) brachytherapy was originally proposed to combine the therapeutic advantages of high-dose-rate (HDR) and low-dose-rate brachytherapy. Though uncommon in the United States, several facilities employ pulsed-dose-rate brachytherapy in Europe and Canada. Currently, there is no air-kerma strength standard for PDR brachytherapy {sup 192}Ir sources traceable to the National Institute of Standards and Technology. Discrepancies in clinical measurements of the air-kerma strength of the PDR brachytherapy sources using HDR source-calibrated well chambers warrant further investigation.Methods: In this research, the air-kerma strength for an {sup 192}Ir PDR brachytherapy source was compared with the University of Wisconsin Accredited Dosimetry Calibration Laboratory transfer standard well chambers, the seven-distance technique [B. E. Rasmussen et al., 'The air-kerma strength standard for 192Ir HDR sources,' Med. Phys. 38, 6721-6729 (2011)], and the manufacturer's stated value. Radiochromic film and Monte Carlo techniques were also employed for comparison to the results of the measurements.Results: While the measurements using the seven-distance technique were within + 0.44% from the manufacturer's determination, there was a + 3.10% difference between the transfer standard well chamber measurements and the manufacturer's stated value. Results showed that the PDR brachytherapy source has geometric and thus radiological qualities that exhibit behaviors similar to a point source model in contrast to a conventional line source model.Conclusions: The resulting effect of the pointlike characteristics of the PDR brachytherapy source likely account for the differences observed between well chamber and in-air measurements.

  11. Key comparison BIPM.RI(I)-K5 of the air kerma standards of the ININ, Mexico and the BIPM in 137Cs gamma radiation

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Burns, D. T.; Alvarez Romero, J. T.; De la Cruz Hernández, D.; Cabrera Vertti, M. R.; Tovar-Muñoz, V. M.

    2015-01-01

    A direct comparison of the standards for air kerma of the Instituto Nacional de Investigaciones Nucleares (ININ), Mexico, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 137Cs radiation beam of the BIPM in February 2015. The comparison result, evaluated as a ratio of the ININ and the BIPM standards for air kerma, is 1.0048 with a combined standard uncertainty of 2.0 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the ININ, Mexico and the BIPM in 60Co gamma radiation

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Alvarez Romero, J. T.; Tovar-Muñoz, V. M.

    2013-01-01

    A direct comparison of the standards for air kerma of the Instituto Nacional de Investigaciones Nucleares (ININ), Mexico, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in 2012. The comparison result, evaluated as a ratio of the ININ and the BIPM standards for air kerma, is 1.0035 with a combined standard uncertainty of 2.1 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  13. Comparison BIPM.RI(I)-K8 of high dose rate 192Ir brachytherapy standards for reference air kerma rate of the NPL and the BIPM

    NASA Astrophysics Data System (ADS)

    Alvarez, J. T.; Sander, T.; de Pooter, J. A.; Allisy-Roberts, P. J.; Kessler, C.

    2014-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate brachytherapy sources of the National Physical Laboratory (NPL), United Kingdom, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the NPL in June 2010. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NPL and the BIPM standards for reference air kerma rate, is 0.9989 with a combined standard uncertainty of 0.0057. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  14. Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the NIM, China and the BIPM in 60Co gamma radiation

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Burns, D.; Wang, K.; Fan, Y.; Jin, S.; Yang, X.

    2016-01-01

    An indirect comparison of the standards for air kerma of the National Institute of Metrology (NIM), China and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2015. The comparison result, evaluated as a ratio of the NIM and the BIPM standards for air kerma, is 0.9997 with a combined standard uncertainty of 2.7 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  15. Accuracy of Spencer-Attix cavity theory and calculations of fluence correction factors for the air kerma formalism.

    PubMed

    La Russa, D J; Rogers, D W O

    2009-09-01

    EGSnrc calculations of ion chamber response and Spencer-Attix (SA) restricted stopping-power ratios are used to test the assumptions of the SA cavity theory and to assess the accuracy of this theory as it applies to the air kerma formalism for 60Co beams. Consistent with previous reports, the EGSnrc calculations show that the SA cavity theory, as it is normally applied, requires a correction for the perturbation of the charged particle fluence (K(fl)) by the presence of the cavity. The need for K(fl) corrections arises from the fact that the standard prescription for choosing the low-energy threshold delta in the SA restricted stopping-power ratio consistently underestimates the values of delta needed if no perturbation to the fluence is assumed. The use of fluence corrections can be avoided by appropriately choosing delta, but it is not clear how delta can be calculated from first principles. Values of delta required to avoid K(fl) corrections were found to be consistently higher than delta values obtained using the conventional approach and are also observed to be dependent on the composition of the wall in addition to the cavity size. Values of K(fl) have been calculated for many of the graphite-walled ion chambers used by the national metrology institutes around the world and found to be within 0.04% of unity in all cases, with an uncertainty of about 0.02%.

  16. Summary of the BIPM.RI(I)-K5 comparison for air kerma in 137Cs gamma radiation

    NASA Astrophysics Data System (ADS)

    Allisy-Roberts, P. J.; Kessler, C.; Burns, D. T.

    2013-01-01

    International comparisons of air kerma in 137Cs gamma radiation beams have been made at the Bureau International des Poids et Mesures (BIPM) since 1994. Twelve national metrology institutes have taken part, seven of which have repeated the comparison over the intervening years. The key comparison reference value (KCRV) is taken as the BIPM evaluation, each comparison result being the ratio of the national metrology institute (NMI) evaluation to that of the BIPM standard under the same reference conditions. The degrees of equivalence between each NMI and the KCRV and a graphical presentation are given using the most recent published result for eleven NMIs. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  17. Comparison Between the NIST and the KEBS for the Determination of Air Kerma Calibration Coefficients for Narrow X-Ray Spectra and (137)Cs Gamma-Ray Beams.

    PubMed

    O'Brien, Michelle; Minniti, Ronaldo; Masinza, Stanslaus Alwyn

    2010-01-01

    Air kerma calibration coefficients for a reference class ionization chamber from narrow x-ray spectra and cesium 137 gamma-ray beams were compared between the National Institute of Standards and Technology (NIST) and the Kenya Bureau of Standards (KEBS). A NIST reference-class transfer ionization chamber was calibrated by each laboratory in terms of the quantity air kerma in four x-ray reference radiation beams of energies between 80 kV and 150 kV and in a cesium 137 gamma-ray beam. The reference radiation qualities used for this comparison are described in detail in the ISO 4037 publication.[1] The comparison began in September 2008 and was completed in March 2009. The results reveal the degree to which the participating calibration facility can demonstrate proficiency in transferring air kerma calibrations under the conditions of the said facility at the time of the measurements. The comparison of the calibration coefficients is based on the average ratios of calibration coefficients.

  18. Radiological investigations at the "Taiga" nuclear explosion site, part II: man-made γ-ray emitting radionuclides in the ground and the resultant kerma rate in air.

    PubMed

    Ramzaev, V; Repin, V; Medvedev, A; Khramtsov, E; Timofeeva, M; Yakovlev, V

    2012-07-01

    Samples of soil and epigeic lichens were collected from the "Taiga" peaceful nuclear explosion site (61.30°N 56.60°E, the Perm region, Russia) in 2009 and analyzed using high resolution γ-ray spectrometry. For soil samples obtained at six different plots, two products of fission ((137)Cs and (155)Eu), five products of neutron activation ((60)Co, (94)Nb, (152)Eu, (154)Eu, (207)Bi) and (241)Am have been identified and quantified. The maximal activity concentrations of (60)Co, (137)Cs, and (241)Am for the soils samples were measured as 1650, 7100, and 6800 Bq kg(-1) (d.w.), respectively. The deposit of (137)Cs for the top 20 cm of soil on the tested plots at the "Taiga" site ranged from 30 to 1020 kBq m(-2); the maximal value greatly (by almost 3 orders of magnitude) exceeded the regional background (from global fallout) level of 1.4 kBq m(-2). (137)Cs contributes approximately 57% of the total ground inventory of the man-made γ-ray emitters for the six plots tested at the "Taiga" site. The other major radionuclides -(241)Am and (60)Co, constitute around 40%. Such radionuclides as (60)Co, (137)Cs, (241)Am, and (207)Bi have also been determined for the epigeic lichens (genera Cladonia) that colonized certain areas at the ground lip produced by the "Taiga" explosion. Maximal activity concentrations (up to 80 Bq kg(-1) for (60)Co, 580 Bq kg(-1) for (137)Cs, 200 Bq kg(-1) for (241)Am, and 5 Bq kg(-1) for (207)Bi; all are given in terms of d.w.) have been detected for the lower dead section of the organisms. The air kerma rates associated with the anthropogenic sources of gamma radiation have been calculated using the data obtained from the laboratory analysis. For the six plots tested, the kerma rates ranged from 50 to 1200 nGy h(-1); on average, 51% of the dose can be attributed to (137)Cs and 45% to (60)Co. These estimates agree reasonably well with the results of the in situ measurements made during our field survey of the "Taiga" site in August

  19. Calculation of conversion coefficients for air kerma to ambient dose equivalent using transmitted spectra of megavoltage X-rays through concrete.

    PubMed

    Cordeiro, T P V; Silva, A X

    2012-12-01

    With the fast advancement of technology, (60)Co teletherapy units are largely being replaced with medical linear accelerators. In most cases, the linear accelerator tends to be installed in the same room in which the (60)Co teletherapy unit was previously placed. If in-depth structural remodelling is out of the question, high-density concrete is usually used to improve shielding against primary, scatter and leakage radiation originating in the new equipment. This work presents a study based on Monte Carlo simulations of the transmission of some clinical photon spectra (from 6, 10, 15, 18 and 25 MV accelerators) through concrete, considering two different densities. Concrete walls with thickness ranging from 0.70 to 2.0 m were irradiated with 30 cm×30 cm primary beam spectra. The results show that the thickness of the barrier decreases up to ∼65 % when barite (high-density concrete) is used instead of ordinary concrete. The average energies of primary and transmitted beam spectra were also calculated. In addition, conversion coefficients from air kerma to ambient dose equivalent, H*(d)/K(air), and air kerma to effective dose, E/K(air), for photon spectra from the transmitted spectra were calculated and compared. The results suggest that the 10-mm depth is not the best choice to represent the effective dose.

  20. Evaluation of wall correction factor of INER's air-kerma primary standard chamber and dose variation by source displacement for HDR ¹⁹²Ir brachytherapy.

    PubMed

    Lee, J H; Wang, J N; Huang, T T; Su, S H; Chang, B J; Su, C H; Hsu, S M

    2013-01-01

    The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR) ¹⁹²Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the ¹⁹²Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR ¹⁹²Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR ¹⁹²Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity.

  1. Air kerma standard for calibration of well-type chambers in Brazil using {sup 192}Ir HDR sources and its traceability

    SciTech Connect

    Di Prinzio, Renato; Almeida, Carlos Eduardo de

    2009-03-15

    In Brazil there are over 100 high dose rate (HDR) brachytherapy facilities using well-type chambers for the determination of the air kerma rate of {sup 192}Ir sources. This paper presents the methodology developed and extensively tested by the Laboratorio de Ciencias Radiologicas (LCR) and presently in use to calibrate those types of chambers. The system was initially used to calibrate six well-type chambers of brachytherapy services, and the maximum deviation of only 1.0% was observed between the calibration coefficients obtained and the ones in the calibration certificate provided by the UWADCL. In addition to its traceability to the Brazilian National Standards, the whole system was taken to University of Wisconsin Accredited Dosimetry Calibration Laboratory (UWADCL) for a direct comparison and the same formalism to calculate the air kerma was used. The comparison results between the two laboratories show an agreement of 0.9% for the calibration coefficients. Three Brazilian well-type chambers were calibrated at the UWADCL, and by LCR, in Brazil, using the developed system and a clinical HDR machine. The results of the calibration of three well chambers have shown an agreement better than 1.0%. Uncertainty analyses involving the measurements made both at the UWADCL and LCR laboratories are discussed.

  2. Assessment of protocols in cone-beam CT with symmetric and asymmetric beams usingeffective dose and air kerma-area product.

    PubMed

    Batista, Wilson Otto; Soares, Maria Rosangela; de Oliveira, Marcus V L; Maia, Ana F; Caldas, Linda V E

    2015-06-01

    This study aims to evaluate and compare protocols with similar purposes in a cone beam CT scanner using thermoluminescent dosimeter (TLD) and the air kerma-area product (PKA) as the kerma index. The measurements were performed on two protocols used to obtain an image of the maxilla-mandible using the equipment GENDEX GXCB 500: Protocol [GX1] extended diameter and asymmetric beam (14cm×8.5cm-maxilla/mandible) and protocol [GX2] symmetrical beam (8.5cm×8.5cm-maxillary/mandible). LiF dosimeters inserted into a female anthropomorphic phantom were used. For both protocols, the value of PKA was evaluated using a PTW Diamentor E2 meter and the multimeter Radcal Rapidose system. The results obtained for the effective dose/PKA were separated by protocol image. [GX1]: 44.5µSv/478mGycm(2); [GX2]: 54.8µSv/507mGycm(2). Although the ratio of the diameters (14cm/8.5cm)=1.65, the ratio of effective dose values (44.5µSv/54.8µSv)=0.81, that is, the effective dose of the protocol with extended diameter is 19% smaller. The PKA values reveal very similar results between the two protocols. For the cases where the scanner uses an asymmetric beam to obtain images with large diameters that cover the entire face, there are advantages from the point of view of reducing the exposure of patients when compared to the use of symmetrical beam and/or to FOV images with a smaller diameter.

  3. Comparison of air kerma measurements for tungsten anode based mammography x-ray beam qualities (EURAMET.RI(I)-S4.1)

    NASA Astrophysics Data System (ADS)

    Csete, I.; Büermann, L.; Gomola, I.

    2016-01-01

    A comparison of the air kerma standards for x-radiation qualities used in mammography was performed between the PTB and the IAEA. Two reference-class ionization chamber types Radcal RC6M and Magna A650 of the IAEA and tungsten anode based beam qualities with Mo and Al external filtrations (W+Mo, W+Al) established at both laboratories were selected for the comparison. The calibration coefficients, NK_air, were determined for the transfer chambers at the PTB in May 2015 and before and after this at the IAEA Dosimetry Laboratory. The results show good agreement, to be well within the 0.55 % standard uncertainty of the comparison. Correction factors to determine NK_air for these beam qualities based on calibration in RQR-M mammography beam qualities, established according to the IEC 61267 standard, were also calculated for the Radcal RC6M, 10X5-6M, and Magna A650 types of chambers. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  4. Comparison of air kerma standards of LNE-LNHB and NPL for 192Ir HDR brachytherapy sources: EUROMET project no 814.

    PubMed

    Douysset, Guilhem; Sander, Thorsten; Gouriou, Jean; Nutbrown, Rebecca

    2008-03-21

    An indirect comparison has been made in the air kerma standards for high dose rate (HDR) 192Ir brachytherapy sources at the Laboratoire National Henri Becquerel (LNHB) and the National Physical Laboratory (NPL). The measurements were carried out at both laboratories between November and December 2004. The comparison was based on measurements using well-type transfer ionization chambers and two different source types, Nucletron microSelectron HDR Classic and version 2. The results show the reported calibration coefficients to agree within 0.47% to 0.63%, which is within the overall standard uncertainty of 0.65% reported by both laboratories at the time of this comparison. Following this comparison, some of the NPL primary standard correction factors were re-evaluated resulting in a change of +0.17% in the overall correction factor. The new factor was implemented in May 2006. Applying the revised chamber factor to the measurements reported in this comparison report will reduce the difference between the two standards by 0.17%.

  5. Modelling the contribution of individual radionuclides to the total gamma air kerma rate for the sediments of the Ribble Estuary, NW England.

    PubMed

    Brown, J E; McDonald, P; Williams, M; Parker, A; Rae, J E

    1999-12-01

    The aim of this study was to test the performance of a published dose-rate model, investigate the contribution of individual radionuclides to the total gamma air kerma rate (GAKR) and derive external doses to man in the Ribble Estuary, NW England. GAKRs were measured and sediment cores were collected in order to determine radionuclide specific activities with depth. The latter values were used as input data for the external dose-rate model. The model has a slight tendency to over-predict the GAKR, but, on average, the model predictions fall within +/-26% of the measured value. Improvements, in the present case, might be made by accounting for core shortening and variations in soil density in the input data. The model predicted that, for exposed intertidal mud sites, a range of GAKRs between 0.011 and 0.022 microGy h(-1) was attributable to Springfields discharges alone. The contribution due to 234mPa and 234Th ranged between 20 and 60%. An excess GAKR (GAKR arising from anthropogenic emissions alone) of 0.139-0.150 microGy h(-1), used in conjunction with relevant habit-survey data (for a potential critical group) and conversion factors, yielded a dose to man of 0.029-0.031 mSv year(-1).

  6. SU-E-T-552: Monte Carlo Calculation of Correction Factors for a Free-Air Ionization Chamber in Support of a National Air-Kerma Standard for Electronic Brachytherapy

    SciTech Connect

    Mille, M; Bergstrom, P

    2015-06-15

    Purpose: To use Monte Carlo radiation transport methods to calculate correction factors for a free-air ionization chamber in support of a national air-kerma standard for low-energy, miniature x-ray sources used for electronic brachytherapy (eBx). Methods: The NIST is establishing a calibration service for well-type ionization chambers used to characterize the strength of eBx sources prior to clinical use. The calibration approach involves establishing the well-chamber’s response to an eBx source whose air-kerma rate at a 50 cm distance is determined through a primary measurement performed using the Lamperti free-air ionization chamber. However, the free-air chamber measurements of charge or current can only be related to the reference air-kerma standard after applying several corrections, some of which are best determined via Monte Carlo simulation. To this end, a detailed geometric model of the Lamperti chamber was developed in the EGSnrc code based on the engineering drawings of the instrument. The egs-fac user code in EGSnrc was then used to calculate energy-dependent correction factors which account for missing or undesired ionization arising from effects such as: (1) attenuation and scatter of the x-rays in air; (2) primary electrons escaping the charge collection region; (3) lack of charged particle equilibrium; (4) atomic fluorescence and bremsstrahlung radiation. Results: Energy-dependent correction factors were calculated assuming a monoenergetic point source with the photon energy ranging from 2 keV to 60 keV in 2 keV increments. Sufficient photon histories were simulated so that the Monte Carlo statistical uncertainty of the correction factors was less than 0.01%. The correction factors for a specific eBx source will be determined by integrating these tabulated results over its measured x-ray spectrum. Conclusion: The correction factors calculated in this work are important for establishing a national standard for eBx which will help ensure that dose

  7. Comparison between absorbed dose to water standards established by water calorimetry at the LNE-LNHB and by application of international air-kerma based protocols for kilovoltage medium energy x-rays.

    PubMed

    Perichon, N; Rapp, B; Denoziere, M; Daures, J; Ostrowsky, A; Bordy, J-M

    2013-05-07

    Nowadays, the absorbed dose to water for kilovoltage x-ray beams is determined from standards in terms of air-kerma by application of international dosimetry protocols. New standards in terms of absorbed dose to water has just been established for these beams at the LNE-LNHB, using water calorimetry, at a depth of 2 cm in water in accordance with protocols. The aim of this study is to compare these new standards in terms of absorbed dose to water, to the dose values calculated from the application of four international protocols based on air-kerma standards (IAEA TRS-277, AAPM TG-61, IPEMB and NCS-10). The acceleration potentials of the six beams studied are between 80 and 300 kV with half-value layers between 3.01 mm of aluminum and 3.40 mm of copper. A difference between the two methods smaller than 2.1% was reported. The standard uncertainty of water calorimetry being below 0.8%, and the one associated with the values from protocols being around 2.5%, the results are in good agreement. The calibration coefficients of some ionization chambers in terms of absorbed dose to water, established by application of calorimetry and air-kerma based dosimetry protocols, were also compared. The best agreement with the calibration coefficients established by water calorimetry was found for those established with the AAPM TG-61 protocol.

  8. AIR KERMA TO Hp(3) CONVERSION COEFFICIENTS FOR IEC 61267 RQR X-RAY RADIATION QUALITIES: APPLICATION TO DOSE MONITORING OF THE LENS OF THE EYE IN MEDICAL DIAGNOSTICS.

    PubMed

    Principi, S; Guardiola, C; Duch, M A; Ginjaume, M

    2016-09-01

    Recent studies highlight the fact that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens monitoring could be required for these workers. The recommended operational quantity for monitoring of eye lens exposure is the personal dose equivalent at 3 mm depth Hp(3) (ICRU 51). However, there are no available conversion coefficients in international standards, while in the literature coefficients have only been calculated for monoenergetic beams and for ISO 4037-1 X-ray qualities. The aim of this article is to provide air kerma to Hp(3) conversion coefficients for a cylindrical phantom made of ICRU-4 elements tissue-equivalent material for RQR radiation qualities (IEC-61267) from 40 to 120 kV and for angles of incidence from 0 to 180°, which are characteristic of medical workplace. Analytic calculations using interpolation techniques and Monte Carlo modelling have been compared.

  9. Key Comparison APMP.RI(I)-K2 of air kerma standards for the CCRI reference radiation qualities for low-energy x-rays, including a supplementary comparison for the ISO 4037 narrow spectrum series

    NASA Astrophysics Data System (ADS)

    Tanaka, T.; Saito, N.; Bero, M.; Butler, D.; Mahant, A. K.; Meghzifene, A.; Chu, C. H.; Kadni, T. B.; Jinjie, WU; Soodprasert, T.

    2014-01-01

    An indirect comparison was performed between nine national standards for air kerma for the CCRI radiation qualities from 10 kV to 50 kV (APMP.RI(I)-K2) and for the ISO 4037 narrow spectrum series (15 kV and 40 kV). Among the nine institutes that participated in the comparison, seven institutes were APMP member laboratories. Three commercially available thin window parallel plate ionization chambers were used as transfer instruments and circulated among the participants. The pilot laboratory, the NMIJ/AIST, served also as the link to the corresponding BIPM.RI(I)-K2 comparison. The results show general agreement within the combined uncertainties, although certain results for Nuclear Malaysia, the BARC and the OAP show larger differences. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  10. Practical method for determination of air kerma by use of an ionization chamber toward construction of a secondary X-ray field to be used in clinical examination rooms.

    PubMed

    Maehata, Itsumi; Hayashi, Hiroaki; Kimoto, Natsumi; Takegami, Kazuki; Okino, Hiroki; Kanazawa, Yuki; Tominaga, Masahide

    2016-07-01

    We propose a new practical method for the construction of an accurate secondary X-ray field using medical diagnostic X-ray equipment. For accurate measurement of the air kerma of an X-ray field, it is important to reduce and evaluate the contamination rate of scattered X-rays. To determine the rate quantitatively, we performed the following studies. First, we developed a shield box in which an ionization chamber could be set at an inner of the box to prevent detection of the X-rays scattered from the air. In addition, we made collimator plates which were placed near the X-ray source for estimation of the contamination rate by scattered X-rays from the movable diaphragm which is a component of the X-ray equipment. Then, we measured the exposure dose while changing the collimator plates, which had diameters of 25-90 mm(ϕ). The ideal value of the exposure dose was derived mathematically by extrapolation to 0 mm(ϕ). Tube voltages ranged from 40 to 130 kV. Under these irradiation conditions, we analyzed the contamination rate by the scattered X-rays. We found that the contamination rates were less than 1.7 and 2.3 %, caused by air and the movable diaphragm, respectively. The extrapolated value of the exposure dose has been determined to have an uncertainty of 0.7 %. The ionization chamber used in this study was calibrated with an accuracy of 5 %. Using this kind of ionization chamber, we can construct a secondary X-ray field with an uncertainty of 5 %.

  11. In-patient to isocenter KERMA ratios in CT

    SciTech Connect

    Huda, Walter; Ogden, Kent M.; Lavallee, Robert L.; Roskopf, Marsha L.; Scalzetti, Ernest M.

    2011-10-15

    Purpose: To estimate in-patient KERMA for specific organs in computed tomography (CT) scanning using ratios to isocenter free-in-air KERMA obtained using a Rando phantom.Method: A CT scan of an anthropomorphic phantom results in an air KERMA K at a selected phantom location and air kerma K{sub CT} at the CT scanner isocenter when the scan is repeated in the absence of the phantom. The authors define the KERMA ratio (R{sub K}) as K/ K{sub CT}, which were experimentally determined in a Male Rando Phantom using lithium fluoride chips (TLD-100). R{sub K} values were obtained for a total of 400 individual point locations, as well as for 25 individual organs of interest in CT dosimetry. CT examinations of Rando were performed on a GE LightSpeed Ultra scanner operated at 80 kV, 120 kV, and 140 kV, as well as a Siemens Sensation 16 operated at 120 kV. Results: At 120 kV, median R{sub K} values for the GE and Siemens scanners were 0.60 and 0.64, respectively. The 10th percentile R{sub K} values ranged from 0.34 at 80 kV to 0.54 at 140 kV, and the 90th percentile R{sub K} values ranged from 0.64 at 80 kV to 0.78 at 140 kV. The average R{sub K} for the 25 Rando organs at 120 kV was 0.61 {+-} 0.08. Average R{sub K} values in the head, chest, and abdomen showed little variation. Relative to R{sub K} values in the head, chest, and abdomen obtained at 120 kV, R{sub K} values were about 12% lower in the pelvis and about 58% higher in the cervical spine region. Average R{sub K} values were about 6% higher on the Siemens Sensation 16 scanner than the GE LightSpeed Ultra. Reducing the x-ray tube voltage from 120 kV to 80 kV resulted in an average reduction in R{sub K} value of 34%, whereas increasing the x-ray tube voltage to 140 kV increased the average R{sub K} value by 9%. Conclusions: In-patient to isocenter relative KERMA values in Rando phantom can be used to estimate organ doses in similar sized adults undergoing CT examinations from easily measured air KERMA values at the

  12. Comparison of conversion coefficients for equivalent dose in terms of air kerma for photons using a male adult voxel simulator in sitting and standing posture with geometry of irradiation antero-posterior

    NASA Astrophysics Data System (ADS)

    Galeano, D. C.; Cavalcante, F. R.; Carvalho, A. B.; Hunt, J.

    2014-02-01

    The dose conversion coefficient (DCC) is important to quantify and assess effective doses associated with medical, professional and public exposures. The calculation of DCCs using anthropomorphic simulators and radiation transport codes is justified since in-vivo measurement of effective dose is extremely difficult and not practical for occupational dosimetry. DCCs have been published by the ICRP using simulators in a standing posture, which is not always applicable to all exposure scenarios, providing an inaccurate dose estimation. The aim of this work was to calculate DCCs for equivalent dose in terms of air kerma (H/Kair) using the Visual Monte Carlo (VMC) code and the VOXTISS8 adult male voxel simulator in sitting and standing postures. In both postures, the simulator was irradiated by a plane source of monoenergetic photons in antero-posterior (AP) geometry. The photon energy ranged from 15 keV to 2 MeV. The DCCs for both postures were compared and the DCCs for the standing simulator were higher. For certain organs, the difference of DCCs were more significant, as in gonads (48% higher), bladder (16% higher) and colon (11% higher). As these organs are positioned in the abdominal region, the posture of the anthropomorphic simulator modifies the form in which the radiation is transported and how the energy is deposited. It was also noted that the average percentage difference of conversion coefficients was 33% for the bone marrow, 11% for the skin, 13% for the bone surface and 31% for the muscle. For other organs, the percentage difference of the DCCs for both postures was not relevant (less than 5%) due to no anatomical changes in the organs of the head, chest and upper abdomen. We can conclude that is important to obtain DCCs using different postures from those present in the scientific literature.

  13. Comparison of pediatric radiation dose and vessel visibility on angiographic systems using piglets as a surrogate: anti-scatter grid removal vs lower detector air kerma settings with a grid - a preclinical investigation.

    PubMed

    Strauss, Keith J; Racadio, John M; Abruzzo, Todd A; Johnson, Neil D; Patel, Manish N; Kukreja, Kamlesh U; den Hartog, Mark J H; Hoonaert, Bart P A; Nachabe, Rami A

    2015-09-08

    The purpose of this study was to reduce pediatric doses while maintaining or improv-ing image quality scores without removing the grid from X-ray beam. This study was approved by the Institutional Animal Care and Use Committee. Three piglets (5, 14, and 20 kg) were imaged using six different selectable detector air kerma (Kair) per frame values (100%, 70%, 50%, 35%, 25%, 17.5%) with and without the grid. Number of distal branches visualized with diagnostic confidence relative to the injected vessel defined image quality score. Five pediatric interventional radiologists evaluated all images. Image quality score and piglet Kair were statistically compared using analysis of variance and receiver operating curve analysis to define the preferred dose setting and use of grid for a visibility of 2nd and 3rd order vessel branches. Grid removal reduced both dose to subject and imaging quality by 26%. Third order branches could only be visualized with the grid present; 100% detector Kair was required for smallest pig, while 70% detector Kair was adequate for the two larger pigs. Second order branches could be visualized with grid at 17.5% detector Kair for all three pig sizes. Without the grid, 50%, 35%, and 35% detector Kair were required for smallest to largest pig, respectively. Grid removal reduces both dose and image quality score. Image quality scores can be maintained with less dose to subject with the grid in the beam as opposed to removed. Smaller anatomy requires more dose to the detector to achieve the same image quality score.

  14. Comparison of conversion coefficients for equivalent dose in terms of air kerma using a sitting and standing female adult voxel simulators exposure to photons in antero-posterior irradiation geometry

    NASA Astrophysics Data System (ADS)

    Cavalcante, F. R.; Galeano, D. C.; Carvalho Júnior, A. B.; Hunt, J.

    2014-02-01

    Due to the difficulty in implementing invasive techniques for calculations of dose for some exposure scenarios, computational simulators have been created to represent as realistically as possible the structures of the human body and through radiation transport simulations to obtain conversion coefficients (CCs) to estimate dose. In most published papers simulators are implemented in the standing posture and this may not describe a real scenario of exposure. In this work we developed exposure scenarios in the Visual Monte Carlo (VMC) code using a female simulator in standing and sitting postures. The simulator was irradiated in the antero-posterior (AP) geometry by a plane source of monoenergetic photons with energy from 10 keV to 2 MeV. The conversion coefficients for equivalent dose in terms of air kerma (HT/Kair) were calculated for both scenarios and compared. The results show that the percentage difference of CCs for the organs of the head and thorax was not significant (less than 5%) since the anatomic position of the organs is the same in both postures. The percentage difference is more significant to the ovaries (71% for photon energy of 20 keV), to the bladder (39% at 60 keV) and to the uterus (37% at 100 keV) due to different processes of radiation interactions in the legs of the simulator when its posture is changed. For organs and tissues that are distributed throughout the entire body, such as bone (21% at 100 keV) and muscle (30% at 80 keV) the percentage difference of CCs reflects a reduction of interaction of photons with the legs of the simulator. Therefore, the calculation of conversion coefficients using simulators in the sitting posture is relevant for a more accurate dose estimation in real exposures to radiation.

  15. Measurement of the ambient gamma dose equivalent and kerma from the small 252Cf source at 1 meter and the small 60Co source at 2 meters

    SciTech Connect

    Carl, W. F.

    2015-07-30

    NASA Langley Research Center requested a measurement and determination of the ambient gamma dose equivalent rate and kerma at 100 cm from the 252Cf source and determination of the ambient gamma dose equivalent rate and kerma at 200 cm from the 60Co source for the Radiation Budget Instrument Experiment (Rad-X). An Exradin A6 ion chamber with Shonka air-equivalent plastic walls in combination with a Supermax electrometer were used to measure the exposure rate and free-in-air kerma rate of the two sources at the requested distances. The measured gamma exposure, kerma, and dose equivalent rates are tabulated.

  16. Photon extremity absorbed dose and kerma conversion coefficients for calibration geometries.

    PubMed

    Veinot, K G; Hertel, N E

    2007-02-01

    Absorbed dose and dose equivalent conversion coefficients are routinely used in personnel dosimetry programs. These conversion coefficients can be applied to particle fluences or to measured air kerma values to determine appropriate operational monitoring quantities such as the ambient dose equivalent or personal dose equivalent for a specific geometry. For personnel directly handling materials, the absorbed dose to the extremities is of concern. This work presents photon conversion coefficients for two extremity calibration geometries using finger and wrist/arm phantoms described in HPS N13.32. These conversion coefficients have been calculated as a function of photon energy in terms of the kerma and the absorbed dose using Monte Carlo techniques and the calibration geometries specified in HPS N13.32. Additionally, kerma and absorbed dose conversion coefficients for commonly used x-ray spectra and calibration source fields are presented. The kerma values calculated in this work for the x-ray spectra and calibration sources compare well to those listed in HPS N13.32. The absorbed dose values, however, differ significantly for higher energy photons because charged particle equilibrium conditions have not been satisfied for the shallow depth. Thus, the air-kerma-to-dose and exposure-to-dose conversion coefficients for Cs and Co listed in HPS N13.32 overestimate the absorbed dose to the extremities. Applying the conversion coefficients listed in HPS N13.32 for Cs, for example, would result in an overestimate of absorbed dose of 62% for the finger phantom and 55% for the wrist phantom.

  17. Kerma factors for use in 37-group neutron spectrum calculations

    NASA Astrophysics Data System (ADS)

    Zeman, G. H.; Bice, W. S., Jr.

    1983-12-01

    Neutron kerma factors have been regrouped from the format of the International Commission on Radiation Units and Measurements Report 26 (ICRU-26) to supplement those available in the 37-group format of the Oak Ridge Data Library Collection 31 (DLC-31). Lists of regrouped neutron kerma factors are presented for eight elements and for seven compounds and mixtures. For several elements, disagreements in excess of 15% were observed between those neutron kerma factors available in DLC-31 and the regrouped neutron kerma factors of ICRU-26.

  18. Processing AIRS Scientific Data Through Level 3

    NASA Technical Reports Server (NTRS)

    Granger, Stephanie; Oliphant, Robert; Manning, Evan

    2010-01-01

    The Atmospheric Infra-Red Sounder (AIRS) Science Processing System (SPS) is a collection of computer programs, known as product generation executives (PGEs). The AIRS SPS PGEs are used for processing measurements received from the AIRS suite of infrared and microwave instruments orbiting the Earth onboard NASA's Aqua spacecraft. Early stages of the AIRS SPS development were described in a prior NASA Tech Briefs article: Initial Processing of Infrared Spectral Data (NPO-35243), Vol. 28, No. 11 (November 2004), page 39. In summary: Starting from Level 0 (representing raw AIRS data), the AIRS SPS PGEs and the data products they produce are identified by alphanumeric labels (1A, 1B, 2, and 3) representing successive stages or levels of processing. The previous NASA Tech Briefs article described processing through Level 2, the output of which comprises geo-located atmospheric data products such as temperature and humidity profiles among others. The AIRS Level 3 PGE samples selected information from the Level 2 standard products to produce a single global gridded product. One Level 3 product is generated for each day s collection of Level 2 data. In addition, daily Level 3 products are aggregated into two multiday products: an eight-day (half the orbital repeat cycle) product and monthly (calendar month) product.

  19. Acetabular pneumatocyst containing air-fluid level.

    PubMed

    Narváez, J A; Narváez, J; Rodríguez-Mijarro, M; Quintero, J C

    1999-01-01

    The presence of intraosseous gas most commonly occurs in osteomyelitis, vacuum phenomenon, and postsurgery or posttraumatic states. Several cases of subchondral gas-filled lesions, called pneumatocysts, have also been described in the sacroiliac joint and clavicle, none of them with intralesional air-fluid level. These pneumatocysts are innocuous lesions of uncertain origin. We describe one case of acetabular pneumatocyst containing air-fluid level in a 62-year-old man with long-standing ankylosing spondylitis involving hip joint. To our knowledge, this is the first reported case of a pneumatocyst in an acetabular location containing air-fluid level.

  20. Elucidating inequality in Nubia: an examination of entheseal changes at Kerma (Sudan).

    PubMed

    Schrader, Sarah A

    2015-02-01

    Located 10 km south of the Third Cataract of the Nile River, the ancient city of Kerma was once capital to the second largest state in Africa. The Eastern Cemetery at Kerma (∼4 km east of city center) encompasses 80+ hectares and was used over a period of 1,500 years (3,200-1,500 BC). Excavated in the early 20th century by George Reisner, the cemetery contained an estimated 20,000-40,000 individuals. Reisner classified these burials into multiple categories, including chiefs and human sacrifices, based on burial position and grave goods. This study investigates the skeletal embodiment of social inequality by examining variation in entheseal severity between the Kerma burial classifications. Seventeen entheses were examined using the Hawkey and Merbs (1995) scoring method (n = 205 individuals); age, sex, and body size variables were considered by employing Mann-Whitney U tests and partial Spearman's correlations. This analysis suggests that significant differences in entheseal changes existed between select burial types. Specifically, "corridor sacrifices" had significantly higher rates of entheseal changes while "chiefs" and "subsidiary burials" had similar entheseal changes; furthermore, within these burial categories, males had higher entheseal scores despite body size controls. The elevated entheseal changes in the sacrificial burials may be due to an intensive agro-pastoral lifestyle or other demanding forms of manual labor. In conclusion, the disparity of entheseal markers between burial subgroups at Kerma might reflect a degree of social inequality within this state level society. This bioarchaeological research informs our understanding of socially-defined categories of persons as well as everyday life in Ancient Kerma.

  1. Processing AIRS Scientific Data Through Level 2

    NASA Technical Reports Server (NTRS)

    Oliphant, Robert; Lee, Sung-Yung; Chahine, Moustafa; Susskind, Joel; arnet, Christopher; McMillin, Larry; Goldberg, Mitchell; Blaisdell, John; Rosenkranz, Philip; Strow, Larrabee

    2007-01-01

    The Atmospheric Infrared Spectrometer (AIRS) Science Processing System (SPS) is a collection of computer programs, denoted product generation executives (PGEs), for processing the readings of the AIRS suite of infrared and microwave instruments orbiting the Earth aboard NASA s Aqua spacecraft. AIRS SPS at an earlier stage of development was described in "Initial Processing of Infrared Spectral Data' (NPO-35243), NASA Tech Briefs, Vol. 28, No. 11 (November 2004), page 39. To recapitulate: Starting from level 0 (representing raw AIRS data), the PGEs and their data products are denoted by alphanumeric labels (1A, 1B, and 2) that signify the successive stages of processing. The cited prior article described processing through level 1B (the level-2 PGEs were not yet operational). The level-2 PGEs, which are now operational, receive packages of level-1B geolocated radiance data products and produce such geolocated geophysical atmospheric data products such as temperature and humidity profiles. The process of computing these geophysical data products is denoted "retrieval" and is quite complex. The main steps of the process are denoted microwave-only retrieval, cloud detection and cloud clearing, regression, full retrieval, and rapid transmittance algorithm.

  2. Procedures for establishing and maintaining consistent air-kerma strength standards for low-energy, photon-emitting brachytherapy sources: recommendations of the Calibration Laboratory Accreditation Subcommittee of the American Association of Physicists in Medicine.

    PubMed

    DeWerd, Larry A; Huq, M Saiful; Das, Indra J; Ibbott, Geoffrey S; Hanson, William F; Slowey, Thomas W; Williamson, Jeffrey F; Coursey, Bert M

    2004-03-01

    Low dose rate brachytherapy is being used extensively for the treatment of prostate cancer. As of September 2003, there are a total of thirteen 125I and seven 103Pd sources that have calibrations from the National Institute of Standards and Technology (NIST) and the Accredited Dosimetry Calibration Laboratories (ADCLs) of the American Association of Physicists in Medicine (AAPM). The dosimetry standards for these sources are traceable to the NIST wide-angle free-air chamber. Procedures have been developed by the AAPM Calibration Laboratory Accreditation Subcommittee to standardize quality assurance and calibration, and to maintain the dosimetric traceability of these sources to ensure accurate clinical dosimetry. A description of these procedures is provided to the clinical users for traceability purposes as well as to provide guidance to the manufacturers of brachytherapy sources and ADCLs with regard to these procedures.

  3. The US radiation dosimetry standards for 60Co therapy level beams, and the transfer to the AAPM accredited dosimetry calibration laboratories.

    PubMed

    Minniti, R; Chen-Mayer, H; Seltzer, S M; Huq, M Saiful; Bryson, L; Slowey, T; Micka, J A; DeWerd, L A; Wells, N; Hanson, W F; Ibbott, G S

    2006-04-01

    This work reports the transfer of the primary standard for air kerma from the National Institute of Standards and Technology (NIST) to the secondary laboratories accredited by the American Association of Physics in Medicine (AAPM). This transfer, performed in August of 2003, was motivated by the recent revision of the NIST air-kerma standards for 60Co gamma-ray beams implemented on July 1, 2003. The revision involved a complete recharacterization of the two NIST therapy-level 60Co gamma-ray beam facilities, resulting in new values for the air-kerma rates disseminated by the NIST. Some of the experimental aspects of the determination of the new air-kerma rates are briefly summarized here; the theoretical aspects have been described in detail by Seltzer and Bergstrom ["Changes in the U.S. primary standards for the air-kerma from gamma-ray beams," J. Res. Natl. Inst. Stand. Technol. 108, 359-381 (2003)]. The standard was transferred to reference-class chambers submitted by each of the AAPM Accredited Dosimetry Calibration Laboratories (ADCLs). These secondary-standard instruments were then used to characterize the 60Co gamma-ray beams at the ADCLs. The values of the response (calibration coefficient) of the ADCL secondary-standard ionization chambers are reported and compared to values obtained prior to the change in the NIST air-kerma standards announced on July 1, 2003. The relative change is about 1.1% for all of these chambers, and this value agrees well with the expected change in chambers calibrated at the NIST or at any secondary-standard laboratory traceable to the new NIST standard.

  4. Kerma Factors for Use in 37-Group Neutron Spectrum Calculations

    DTIC Science & Technology

    1983-12-01

    PFPPI TECHNICAL REPORT Kerma factors for use in 37-group neutron spectrum calculations en en CO G. H. Zeman W. S. Bice, Jr. DEFENSE NUCLEAR...AGENCY ARMED FORCES RADIOBIOLOGY RESEARCH INSTITUTE BETHESDA, MARYLAND 20814 APPRCVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED REVIEWED AND...FACTORS FOR USE IN 37-GROUP NEUTRON SPECTRUM CALCULATIONS 7. AUTHORfs; G. H. Zeman and W. S. Bice, Jr. 9. PERFORMING

  5. SU-E-I-27: Estimating KERMA Area Product for CT Localizer Images

    SciTech Connect

    Ogden, K; Greene-Donnelly, K; Bennett, R; Thorpe, M

    2015-06-15

    Purpose: To estimate the free-in-air KERMA-Area Product (KAP) incident on patients due to CT localizer scans for common CT exams. Methods: In-plane beam intensity profiles were measured in localizer acquisition mode using OSLs for a 64 slice MDCT scanner (Lightspeed VCT, GE Medical Systems, Waukesha WI). The z-axis beam width was measured as a function of distance from isocenter. The beam profile and width were used to calculate a weighted average air KERMA per unit mAs as a function of intercepted x-axis beam width for objects symmetric about the localizer centerline.Patient areas were measured using manually drawn regions and divided by localizer length to determine average width. Data were collected for 50 head exams (lateral localizer only), 15 head/neck exams, 50 chest exams, and 50 abdomen/pelvis exams. Mean patient widths and acquisition techniques were used to calculate the weighted average free-in-air KERMA, which was multiplied by the patient area to estimate KAP. Results: Scan technique was 120 kV tube voltage, 10 mA current, and table speed of 10 cm/s. The mean ± standard deviation values of KAP were 120 ± 11.6, 469 ± 62.6, 518 ± 45, and 763 ± 93 mGycm{sup 2} for head, head/neck, chest, and abdomen/pelvis exams, respectively. For studies with AP and lateral localizers, the AP/lateral area ratio was 1.20, 1.33, and 1.24 for the head/neck, chest, and abdomen/pelvis exams, respectively. However, the AP/lateral KAP ratios were 1.12, 1.08, and 1.07, respectively. Conclusion: Calculation of KAP in CT localizers is complicated by the non-uniform intensity profile and z-axis beam width. KAP values are similar to those for simple radiographic exams such as a chest radiograph and represent a small fraction of the x-ray exposure at CT. However, as CT doses are reduced the localizer contribution will be a more significant fraction of the total exposure.

  6. Air Assault - Rapid Response at the Operational Level.

    DTIC Science & Technology

    1988-03-30

    visualize a number of operational applications for air assault units on the European battlefield. The key to their employment at this level is for...concept, one can visualize a number of operational applications for air assault units on the European battlefield. The key to their employment at this level...combat troop carrying and fire support roles for the helicopter. In 1969, the Soviet Union realized a need for this new combat helicopter technology

  7. Secondary bremsstrahlung and the energy-conservation aspects of kerma in photon-irradiated media.

    PubMed

    Kumar, Sudhir; Nahum, Alan E

    2016-02-07

    Kerma, collision kerma and absorbed dose in media irradiated by megavoltage photons are analysed with respect to energy conservation. The user-code DOSRZnrc was employed to compute absorbed dose D, kerma K and a special form of kerma, K ncpt, obtained by setting the charged-particle transport energy cut-off very high, thereby preventing the generation of 'secondary bremsstrahlung' along the charged-particle paths. The user-code FLURZnrc was employed to compute photon fluence, differential in energy, from which collision kerma, K col and K were derived. The ratios K/D, K ncpt/D and K col/D have thereby been determined over a very large volumes of water, aluminium and copper irradiated by broad, parallel beams of 0.1 to 25 MeV monoenergetic photons, and 6, 10 and 15 MV 'clinical' radiotherapy qualities. Concerning depth-dependence, the 'area under the kerma, K, curve' exceeded that under the dose curve, demonstrating that kerma does not conserve energy when computed over a large volume. This is due to the 'double counting' of the energy of the secondary bremsstrahlung photons, this energy being (implicitly) included in the kerma 'liberated' in the irradiated medium, at the same time as this secondary bremsstrahlung is included in the photon fluence which gives rise to kerma elsewhere in the medium. For 25 MeV photons this 'violation' amounts to 8.6%, 14.2% and 25.5% in large volumes of water, aluminium and copper respectively but only 0.6% for a 'clinical' 6 MV beam in water. By contrast, K col/D and K ncpt/D, also computed over very large phantoms of the same three media, for the same beam qualities, are equal to unity within (very low) statistical uncertainties, demonstrating that collision kerma and the special type of kerma, K ncpt, do conserve energy over a large volume. A comparison of photon fluence spectra for the 25 MeV beam at a depth of  ≈51 g cm−2 for both very high and very low charged-particle transport cut-offs reveals the considerable

  8. Secondary bremsstrahlung and the energy-conservation aspects of kerma in photon-irradiated media

    NASA Astrophysics Data System (ADS)

    Kumar, Sudhir; Nahum, Alan E.

    2016-02-01

    Kerma, collision kerma and absorbed dose in media irradiated by megavoltage photons are analysed with respect to energy conservation. The user-code DOSRZnrc was employed to compute absorbed dose D, kerma K and a special form of kerma, K ncpt, obtained by setting the charged-particle transport energy cut-off very high, thereby preventing the generation of ‘secondary bremsstrahlung’ along the charged-particle paths. The user-code FLURZnrc was employed to compute photon fluence, differential in energy, from which collision kerma, K col and K were derived. The ratios K/D, K ncpt/D and K col/D have thereby been determined over a very large volumes of water, aluminium and copper irradiated by broad, parallel beams of 0.1 to 25 MeV monoenergetic photons, and 6, 10 and 15 MV ‘clinical’ radiotherapy qualities. Concerning depth-dependence, the ‘area under the kerma, K, curve’ exceeded that under the dose curve, demonstrating that kerma does not conserve energy when computed over a large volume. This is due to the ‘double counting’ of the energy of the secondary bremsstrahlung photons, this energy being (implicitly) included in the kerma ‘liberated’ in the irradiated medium, at the same time as this secondary bremsstrahlung is included in the photon fluence which gives rise to kerma elsewhere in the medium. For 25 MeV photons this ‘violation’ amounts to 8.6%, 14.2% and 25.5% in large volumes of water, aluminium and copper respectively but only 0.6% for a ‘clinical’ 6 MV beam in water. By contrast, K col/D and K ncpt/D, also computed over very large phantoms of the same three media, for the same beam qualities, are equal to unity within (very low) statistical uncertainties, demonstrating that collision kerma and the special type of kerma, K ncpt, do conserve energy over a large volume. A comparison of photon fluence spectra for the 25 MeV beam at a depth of  ≈51 g cm-2 for both very high and very low charged-particle transport cut

  9. [Field investigations of the air pollution level of populated territories].

    PubMed

    Vinokurov, M V

    2014-01-01

    The assessment and management of air quality of settlements is one of the priorities in the field of environmental protection. In the management of air quality the backbone factor is the methodology of the organization, performance and interpretation of data of field investigations. The present article is devoted to the analysis of the existing methodological approaches and practical aspects of their application in the organization and performance of field investigations with the aim to confirm the adequacy of the boundaries of the sanitary protection zone in the old industrial regions, hygienic evaluation of the data of field investigations of the air pollution level.

  10. Cross sections and partial kerma factors for elastic and inelastic neutron scattering from nitrogen, oxygen and calcium at En = 21.6 MeV.

    PubMed

    Olsson, N; Ramström, E; Trostell, B

    1990-09-01

    The Studsvik high-resolution, low-background time-of-flight facility has been used to measure differential neutron scattering cross sections for nitrogen, oxygen and calcium at a neutron energy of 21.6 MeV. Angular distributions in the range 10 degrees-160 degrees have been measured for both elastic and inelastic scattering from some low-lying levels in the three nuclei. Angle-integrated cross sections have been determined by fitting Legendre polynomial expansions to the differential data. Partial kerma factors for elastic and inelastic scattering have been deduced from these fits. Analyses in terms of the spherical optical model and the distorted-wave Born approximation have provided information on potential parameters and deformations, which have been used to calculate cross sections and partial kerma factors. Comparisons have been made with other recent data sets and model predictions, as well as with the evaluated neutron data file ENDF/B-V.

  11. Higher fuel prices are associated with lower air pollution levels.

    PubMed

    Barnett, Adrian G; Knibbs, Luke D

    2014-05-01

    Air pollution is a persistent problem in urban areas, and traffic emissions are a major cause of poor air quality. Policies to curb pollution levels often involve raising the price of using private vehicles, for example, congestion charges. We were interested in whether higher fuel prices were associated with decreased air pollution levels. We examined an association between diesel and petrol prices and four traffic-related pollutants in Brisbane from 2010 to 2013. We used a regression model and examined pollution levels up to 16 days after the price change. Higher diesel prices were associated with statistically significant short-term reductions in carbon monoxide and nitrogen oxides. Changes in petrol prices had no impact on air pollution. Raising diesel taxes in Australia could be justified as a public health measure. As raising taxes is politically unpopular, an alternative political approach would be to remove schemes that put a downward pressure on fuel prices, such as industry subsidies and shopping vouchers that give fuel discounts.

  12. BOREAS AFM-5 Level-1 Upper Air Network Data

    NASA Technical Reports Server (NTRS)

    Barr, Alan; Hrynkiw, Charmaine; Newcomer, Jeffrey A. (Editor); Hall, Forrest G. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-5 team collected and processed data from the numerous radiosonde flights during the project. The goals of the AFM-05 team were to provide large-scale definition of the atmosphere by supplementing the existing Atmospheric Environment Service (AES) aerological network, both temporally and spatially. This data set includes basic upper-air parameters collected from the network of upper-air stations during the 1993, 1994, and 1996 field campaigns over the entire study region. The data are contained in tabular ASCII files. The level-1 upper-air network data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files also are available on a CD-ROM (see document number 20010000884).

  13. Air quality and thermal comfort levels under extreme hot weather

    NASA Astrophysics Data System (ADS)

    Papanastasiou, D. K.; Melas, D.; Kambezidis, H. D.

    2015-01-01

    Meteorological (T and RH values) and air pollution data (PM10, NO2 and O3 concentrations) observed in Athens, Thessaloniki and Volos were analyzed to assess the air quality and the thermal comfort conditions and to study their synergy, when extreme hot weather prevailed in Greece during the period 2001-2010. The identification of a heat wave day was based on the suggestion made by the IPCC to define an extreme weather event. According to it, a heat wave day is detected when the daily maximum hourly temperature value exceeds its 90th percentile. This temperature criterion was applied to the data recorded at the cities center. Air quality was assessed at three sites in Athens (city center, near the city center, suburb), at two sites in Thessaloniki (city center, suburb) and at one site in Volos (city center), while thermal comfort conditions were assessed at the cities center. Mean pollution levels during the heat wave days and the non-heat wave days were calculated in order to examine the impact of the extreme hot weather on air quality. For this purpose, the distributions of the common air quality index and the exceedances of the air quality standards in force during the heat wave days and the non-heat wave days were also studied. Additionally, the variation of the daily maximum hourly value of Thom's discomfort index was studied in order to investigate the effect of extreme hot weather on people's thermal comfort. Moreover, the values of the common air quality index and Thom's discomfort index were comparatively assessed so as to investigate their synergy under extreme hot weather.

  14. Correlation of air temperature above water-air sections with the forecasted low level clouds

    NASA Astrophysics Data System (ADS)

    Huseynov, N. Sh.; Malikov, B. M.

    2009-04-01

    As a case study approach the development of low clouds forecasting methods in correlation with air temperature transformational variations on the sections "water-air" is surveyed. It was evident, that transformational variations of air temperature mainly depend on peculiarities and value of advective variations of temperature. DT is the differences of initial temperature on section water-air in started area, from contrast temperature of water surface along a trajectory of movement of air masses and from the temperature above water surface in a final point of a trajectory. Main values of transformational variations of air temperature at advection of a cold masses is 0.530C•h, and at advection of warm masses is -0.370C•h. There was dimensionless quantity K determined and implemented into practice which was characterized with difference of water temperature in forecasting point and air temperature in an initial point in the ratio of dew-points deficiency at the forecasting area. It follows, that the appropriate increasing or decreasing of K under conditions of cold and warm air masses advection, contributes decreasing of low clouds level. References: Abramovich K.G.: Conditions of development and forecasting of low level clouds. vol. #78, 124 pp., Hydrometcenter USSR 1973. Abramovich K.G.: Variations of low clouds level // Meteorology and Hydrology, vol. # 5, 30-41, Moscow, 1968. Budiko M.I.: Empirical assessment of climatic changes toward the end of XX century // Meteorology and Hydrology, vol. #12, 5-13, Moscow, 1999. Buykov M.V.: Computational modeling of daily evolutions of boundary layer of atmosphere at the presence of clouds and fog // Meteorology and Hydrology, vol. # 4, 35-44, Moscow, 1981. Huseynov N.Sh. Transformational variations of air temperature above Caspian Sea / Proceedings of Conference On Climate And Protection of Environment, 118-120, Baku, 1999. Huseynov N.Sh.: Consideration of advective and transformational variations of air temperature in

  15. Mixing layer height and air pollution levels in urban area

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Wagner, Patrick; Emeis, Stefan; Jahn, Carsten; Muenkel, Christoph; Suppan, Peter

    2012-10-01

    Ceilometers are applied by KIT/IMK-IFU to detect layering of the lower atmosphere continuously. This is necessary because not only wind speed and direction but also atmospheric layering and especially the mixing layer height (MLH) influence exchange processes of ground level emissions. It will be discussed how the ceilometer monitoring information is used to interpret the air pollution near the ground. The information about atmospheric layering is continuously monitored by uninterrupted remote sensing measurements with the Vaisala ceilometer CL51 which is an eye-safe commercial mini-lidar system. Special software for this ceilometer provides routine retrievals of lower atmosphere layering from vertical profiles of laser backscatter data. An intensive measurement period during the winter 2011/2012 is studied. The meteorological influences upon air pollutant concentrations are investgated and the correlations of air pollutant concentrations with ceilometer MLH are determined. Benzene was detected by department of Applied Climatology and Landscape Ecology, University of Duisburg-Essen (UDE) with a gas chromatograph during the measurement period. The meteorological data are collected by UDE and the monitoring station Essen of the German national meteorological service DWD. The concentrations of the air pollutants NO, NO2 and PM10 are provided by the national air pollution network LANUV.

  16. Gestational Diabetes and Preeclampsia in Association with Air Pollution at Levels below Current Air Quality Guidelines

    PubMed Central

    Jakobsson, Kristina; Tinnerberg, Håkan; Rignell-Hydbom, Anna; Rylander, Lars

    2013-01-01

    Background: Several studies have estimated associations between air pollution and birth outcomes, but few have evaluated potential effects on pregnancy complications. Objective: We investigated whether low-level exposure to air pollution is associated with gestational diabetes and preeclampsia. Methods: High-quality registry information on 81,110 singleton pregnancy outcomes in southern Sweden during 1999–2005 was linked to individual-level exposure estimates with high spatial resolution. Modeled exposure to nitrogen oxides (NOx), expressed as mean concentrations per trimester, and proximity to roads of different traffic densities were used as proxy indicators of exposure to combustion-related air pollution. The data were analyzed by logistic regression, with and without adjusting for potential confounders. Results: The prevalence of gestational diabetes increased with each NOx quartile, with an adjusted odds ratio (OR) of 1.69 (95% CI: 1.41, 2.03) for the highest (> 22.7 µg/m3) compared with the lowest quartile (2.5–8.9 µg/m3) of exposure during the second trimester. The adjusted OR for acquiring preeclampsia after exposure during the third trimester was 1.51 (1.32, 1.73) in the highest quartile of NOx compared with the lowest. Both outcomes were associated with high traffic density, but ORs were significant for gestational diabetes only. Conclusion: NOx exposure during pregnancy was associated with gestational diabetes and preeclampsia in an area with air pollution levels below current air quality guidelines. PMID:23563048

  17. Level-1C Product from AIRS: Principal Component Filtering

    NASA Technical Reports Server (NTRS)

    Manning, Evan M.; Jiang, Yibo; Aumann, Hartmut H.; Elliott, Denis A.; Hannon, Scott

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS), launched on the EOS Aqua spacecraft on May 4, 2002, is a grating spectrometer with 2378 channels in the range 3.7 to 15.4 microns. In a grating spectrometer each individual radiance measurement is largely independent of all others. Most measurements are extremely accurate and have very low noise levels. However, some channels exhibit high noise levels or other anomalous behavior, complicating applications needing radiances throughout a band, such as cross-calibration with other instruments and regression retrieval algorithms. The AIRS Level-1C product is similar to Level-1B but with instrument artifacts removed. This paper focuses on the "cleaning" portion of Level-1C, which identifies bad radiance values within spectra and produces substitute radiances using redundant information from other channels. The substitution is done in two passes, first with a simple combination of values from neighboring channels, then with principal components. After results of the substitution are shown, differences between principal component reconstructed values and observed radiances are used to investigate detailed noise characteristics and spatial misalignment in other channels.

  18. Determinants of elite-level air rifle shooting performance.

    PubMed

    Ihalainen, S; Kuitunen, S; Mononen, K; Linnamo, V

    2016-03-01

    This study focused on identifying the most important factors determining performance in elite-level air rifle shooting technique. Forty international- and national-level shooters completed a simulated air rifle shooting competition series. From a total of 13 795 shots in 319 tests, shooting score and 17 aiming point trajectory variables were measured with an optoelectronic device and six postural balance variables were measured with force platform. Principal component analysis revealed six components in the air rifle shooting technique: aiming time, stability of hold, measurement time, cleanness of triggering, aiming accuracy, and timing of triggering. Multiple regression analysis identified four of those, namely stability of hold, cleanness of triggering, aiming accuracy, and timing of triggering as the most important predictors of shooting performance, accounting for 81% of the variance in shooting score. The direct effect of postural balance on performance was small, accounting for less than 1% of the variance in shooting score. Indirectly, the effect can be greater through a more stable holding ability, to which postural balance was correlated significantly (R = 0.55, P < 0.001). The results of the present study can be used in assessing athletes' technical strengths and weaknesses and in directing training programs on distinct shooting technical components.

  19. An air quality balance index estimating the total amount of air pollutants at ground level.

    PubMed

    Trivero, Paolo; Biamino, Walter; Borasi, Maria; Cavagnero, Marco; Musa, Maya; Rinaudo, Caterina; Sesia, Veronica

    2012-07-01

    A new index named Air Quality Balance Index (AQBI), which is able to characterise the amount of pollution level in a selected area, is proposed. This index is a function of the ratios between pollutant concentration values and their standards; it aims at identifying all situations in which there is a possible environmental risk even when several pollutants are below their limit values but air quality is reduced. AQBI is evaluated by using a high-resolution three-dimensional dispersion model: the air concentration for each substance is computed starting from detailed emissions sources: point, line and area emissions hourly modulated. This model is driven with accurate meteorological data from ground stations and remote sensing systems providing vertical profiles of temperature and wind; these data are integrated with wind and temperature profiles at higher altitudes obtained by a Local Area Model. The outputs of the dispersion model are compared with pollutant concentrations provided by measuring stations, in order to recalibrate emission data. A three-dimensional high resolution grid of AQBI data is evaluated for an industrial area close to Alessandria (Northern Italy), assessing air quality and environmental conditions. Performance of AQBI is compared with the Air Quality Index (AQI) developed by the U.S. Environmental Protection Agency. AQBI, computed taking into account all pollutants, is able to point out situations not evidenced by AQI, based on a preset limited number of substances; therefore, AQBI is a good tool for evaluating the air quality either in urban and in industrial areas. The AQBI values at ground level, in selected points, are in agreement with in situ observations.

  20. Modelled air pollution levels versus EC air quality legislation - results from high resolution simulation.

    PubMed

    Chervenkov, Hristo

    2013-12-01

    An appropriate method for evaluating the air quality of a certain area is to contrast the actual air pollution levels to the critical ones, prescribed in the legislative standards. The application of numerical simulation models for assessing the real air quality status is allowed by the legislation of the European Community (EC). This approach is preferable, especially when the area of interest is relatively big and/or the network of measurement stations is sparse, and the available observational data are scarce, respectively. Such method is very efficient for similar assessment studies due to continuous spatio-temporal coverage of the obtained results. In the study the values of the concentration of the harmful substances sulphur dioxide, (SO2), nitrogen dioxide (NO2), particulate matter - coarse (PM10) and fine (PM2.5) fraction, ozone (O3), carbon monoxide (CO) and ammonia (NH3) in the surface layer obtained from modelling simulations with resolution 10 km on hourly bases are taken to calculate the necessary statistical quantities which are used for comparison with the corresponding critical levels, prescribed in the EC directives. For part of them (PM2.5, CO and NH3) this is done for first time with such resolution. The computational grid covers Bulgaria entirely and some surrounding territories and the calculations are made for every year in the period 1991-2000. The averaged over the whole time slice results can be treated as representative for the air quality situation of the last decade of the former century.

  1. Air quality in Moscow megacity: basic level and extreme cases

    NASA Astrophysics Data System (ADS)

    Pankratova, N.; Skorokhod, A.; Moiseenko, K.

    2012-04-01

    Moscow is one of the largest megacities in the world. Total annual emissions of polluting substances into the atmosphere in Moscow is likely to be about 2,0 mln. t. More than 90% of pollutants are emitted by traffic. Problem of air quality assessment is very urgent for Moscow both to alarm population and to compare with other world megacities. To study contemporary structure of atmospheric pollution over Moscow megacity data on air composition (including CO, NO, NO2, O3, CH4, CO2, SO2, NMHC, aerosol) obtained since 2002 has been analyzed. The monitoring site is located at Moscow State University meteorological observatory on South-West of Moscow. All observations are provided by A.M. Obukhov Institute of Atmospheric Physics RAS. Due to these continuous measurements typical (basic) level of pollution as well as extreme cases have been studied. The relationship between O3, NOx and VOCs were analyzed as well. Due to weather conditions (cyclonic regime is dominated) concentrations of pollutants usually do not reach dangerous levels but sometimes they are high. The case of abnormal hot and dry weather in the summer of 2010 was investigated. Many Russians were suffering from the record-breaking heat and the worst drought in 40 years. The heat was caused by very intensive and stable blocking anticyclone that established in Moscow since June, 18 till August, 18. Anticyclone of such strength has been never observed before. During 33 days in succession surface air temperature exceeded 30°C. During these 2 months troposphere over ETR was almost closed for western winds. Hot weather led to numerous forest and peat fires (about 29,000 cases) with total covered area about 12,000 km2. One of aftermaths was significant change of atmospheric composition. Many cities and settlements were covered by dense haze from fires. Evident presence of high amount of aerosol in the ambient air caused anxiety and application of safeguards. Meanwhile, less obvious increase of concentrations of

  2. Air Quality Planning Unit | Ground-level Ozone | New England ...

    EPA Pesticide Factsheets

    2017-04-10

    Looking for answers about a specific air quality issue? Here's a list of topics and programs related to air quality and Air Quality Planning (AQP) staff who can answer questions and provide information about them.

  3. Air Quality Planning Unit | Ground-level Ozone | New England ...

    EPA Pesticide Factsheets

    2017-02-16

    Looking for answers about a specific air quality issue? Here's a list of topics and programs related to air quality and Air Quality Planning (AQP) staff who can answer questions and provide information about them.

  4. Energy absorption buildup factors, exposure buildup factors and Kerma for optically stimulated luminescence materials and their tissue equivalence for radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Singh, Vishwanath P.; Badiger, N. M.

    2014-11-01

    Optically stimulated luminescence (OSL) materials are sensitive dosimetric materials used for precise and accurate dose measurement for low-energy ionizing radiation. Low dose measurement capability with improved sensitivity makes these dosimeters very useful for diagnostic imaging, personnel monitoring and environmental radiation dosimetry. Gamma ray energy absorption buildup factors and exposure build factors were computed for OSL materials using the five-parameter Geometric Progression (G-P) fitting method in the energy range 0.015-15 MeV for penetration depths up to 40 mean free path. The computed energy absorption buildup factor and exposure buildup factor values were studied as a function of penetration depth and incident photon energy. Effective atomic numbers and Kerma relative to air of the selected OSL materials and tissue equivalence were computed and compared with that of water, PMMA and ICRU standard tissues. The buildup factors and kerma relative to air were found dependent upon effective atomic numbers. Buildup factors determined in the present work should be useful in radiation dosimetry, medical diagnostics and therapy, space dosimetry, accident dosimetry and personnel monitoring.

  5. KERMA-based radiation dose management system for real-time patient dose measurement

    NASA Astrophysics Data System (ADS)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  6. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  7. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  8. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  9. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  10. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  11. The advantages and disadvantages of centralized control of air power at operational level

    NASA Astrophysics Data System (ADS)

    Arisoy, Uǧur

    2014-05-01

    People do not want to see and hear a war. In today's world, if war is inevitable, the use of air power is seen as the preferable means of conducting operations instead of financially burdensome land battles which are more likely to cause heavy loss of life. The use of Air Power has gained importance in NATO operations in the Post-Cold War era. For example, air power has undertaken a decisive role from the beginning to the end of the operation in Libya. From this point of view, the most important issue to consider is how to direct air power more effectively at operational level. NATO's Core JFAC (Joint Force Air Command) was established in 2012 to control joint air power at operational level from a single center. US had experienced JFAC aproach in the Operation Desert Storm in 1991. UK, France, Germany, Italy and Spain are also directing their air power from their JFAC structures. Joint air power can be directed from a single center at operational level by means of JFAC. JFAC aproach provides complex planning progress of Air Power to be controled faster in a single center. An Air Power with a large number of aircrafts, long range missiles of cutting-edge technology may have difficulties in achieving results unless directed effectively. In this article, directing air power more effectively at operational level has been studied in the framework of directing air power from a single center carried out by SWOT analysis technique. "Directing Air Power at operational level from a single center similar to JFAC-like structure" is compared with "Directing Air Power at operational level from two centers similar to AC (Air Command) + CAOC (Combined Air Operations Center) structure" As a result of this study, it is assessed that directing air power at operational level from a single center would bring effectiveness to the air campaign. The study examines directing air power at operational level. Developments at political, strategic and tactical levels have been ignored.

  12. 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...

  13. Entrainment of Upper Level Dry Air Into Hurricane Earl

    NASA Technical Reports Server (NTRS)

    Guillory, Anthony R.; Jedlovec, Gary J.; Hood, Robbie E.; Atkinson, Robert J.; LaFontaine, Frank J.

    1999-01-01

    Hurricane Earl formed in the Gulf of Mexico in September 1998. It quickly was upgraded from a tropical disturbance to tropical storm status and then to a hurricane. Earl possessed hybrid (tropical and extratropical) characteristics throughout its lifetime. The system maintained and erratic track, which led to wide variability in the operational track forecasts. It eventually made landfall on the Florida panhandle on 2 September and raced northeastward. During August and September 1998, NASA conducted the third Convection and Moisture Experiment (CAMEX-3). The experiment was focused on studying hurricanes with an emphasis toward developing a better understanding of their intensification and motion. Earl provides a unique opportunity to utilize high spatial and temporal resolution data collected from the DC-8 and high altitude ER-2 NASA platforms, which flew over Earl as it made landfall. These data can also be put into broader view provided by other instruments from the Geosynchronous Operational Environmental Satellites (GOES) and the Tropical Rainfall Measuring Mission (TRMM) satellites. Hurricane Earl was affected by entrainment of dry air from the northwest. Hurricane Isis was intensifying and approaching the Mexican Pacific coast with its associated outflow potentially affecting the inflow into Earl as the storm neared Florida. In addition, a longwave synoptic trough circulation was present over the eastern U.S. Either or both of these could be responsible for the dry air into the system. This paper will focus on identifying the source of the dry by using upper-level wind and moisture fields derived from the GOES 6.7 um water vapor imagery. We will attempt to relate the large-scale observations to those from the NASA aircraft. An infrared instrument onboard the ER-2 also has a similar wavelength and may be able to confirm some of the GOES findings. In addition, a microwave radiometer with 4 channels focused on measuring precipitation and its associated ice

  14. Radiological background levels found on glass fiber filters used for low-level environmental surveillance air sampling

    SciTech Connect

    Althouse, P. E.

    1998-09-16

    Environmental surveillance of low-level radioactive particles in air requires a thorough understanding of low-level techniques and air sample collection media. High-volume air sampling for radioactive particles around Lawrence Livermore National Laboratory (LLNL) employs glass-fiber filters that are analyzed for gross alpha and gross beta activity and for specific isotopes. This study was conducted to determine the activities of radionuclides contained in blank glass-fiber filters. Data from this study provided a partial explanation of differences between current reported concentrations of radionuclides in air and those reported historically when cellulose filters were used in the LLNL monitoring effort.

  15. Illinois - High-Level Commitment Key to Air Quality Success

    SciTech Connect

    Not Available

    2007-12-01

    This fact sheet highlights how renewable energy and energy efficiency technologies can and are being used to reduce air emissions and meet environmental goals, showcasing case studies and technology-specific topics.

  16. Vandenberg Air Force Base Upper Level Wind Launch Weather Constraints

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Wheeler, Mark M.

    2012-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman III ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The maximum wind speed and 1000-ft shear values for each sounding in each subseason were determined. To accurately calculate the PoV, the AMU determined the theoretical distributions that best fit the maximum wind speed and maximum shear datasets. Ultimately it was discovered that the maximum wind speeds follow a Gaussian distribution while the maximum shear values follow a lognormal distribution. These results were applied when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition to the requirements outlined in the original task plan, the AMU also included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on day of launch. The interactive graphical user interface (GUI) for this project was developed in

  17. 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.

  18. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  19. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  20. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  1. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  2. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  3. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  4. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  5. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  6. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  7. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  8. MEASUREMENT OF LOW LEVEL AIR TOXICS WITH MODIFIED UV DOAS

    EPA Science Inventory

    To further understand near source impacts, EPA is working to develop open-path optical techniques for spatiotemporal-resolved measurement of air pollutants. Of particular interest is near real time quantification of mobile-source generated CO, Nox and hydrocarbons measured in cl...

  9. RELATIONSHIPS BETWEEN LEVELS OF VOLATILE ORGANIC COMPOUNDS IN AIR AND BLOOD FROM THE GENERAL POPULATION

    EPA Science Inventory

    Background: The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at ppb levels. Objectives: This study investigates relationships between ...

  10. Carbon Monoxide | Air Quality Planning Unit | Ground-level ...

    EPA Pesticide Factsheets

    2017-04-10

    Carbon monoxide (CO) is a colorless, odorless gas that can increase the severity of lung ailments, cause dizziness, fatigue, nausea, and even death. EPA has defined the national ambient air quality standard (NAAQS) for carbon monoxide as nine parts per million averaged over an eight-hour period, and this threshold cannot be exceeded more than once a year or an area would be violating the standard.

  11. Development of Level 3 (gridded) products for the Atmospheric Infrared Sounder (AIRS)

    NASA Technical Reports Server (NTRS)

    Granger, Stephanie L.; Leroy, Stephen S.; Manning, Evan M.; Fetzer, Eric J.; Oliphant, Robert B.; Braverman, Amy; Lee, Sung-Yung; Lambrigtsen, Bjom H.

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) sounding system is a suite of infrared and microwave instruments flown as part of NASA's Earth Observing System (EOS) onboard the Aqua platform. The AIRS dataset provides a daily, global view of Earth processes at a finer vertical resolution than ever before. However, analysis of the AIRS data is a daunting task given the sheer volume and complexity of the data. The volume of data produced by the EOS project is unprecedented; the AIRS project alone will produce many terabytes of data over the lifetime of the mission. This paper describes development of AIRS Level 3 data products that will help to alleviate problems of access and usability.

  12. 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 ...

  13. Conduction and Utilization of Research: The Relationship Between Air Force Nurses’ Attitudes, Levels of Education, and Rank

    DTIC Science & Technology

    1999-05-01

    Respondents 22 Table 5. Highest Level of Non- Nursing Education of the Air Force Nurse Respondents 23 Table 6. Overall Highest Level of Education...Force Rank (Good Attitude vs Bad Attitude 41 Table 13. Air Force Nurse Respondents’ Attitudes by Highest Level of Nursing Education 44 Table 14. Air...Figure 2. Research Experience of Air Force Nurse Respondents by Highest Level of Nursing Education (Excellent, Fair or Poor Experience 38 Figure 3. Air

  14. Ground level air convection produces frost damage patterns in turfgrass.

    PubMed

    Ackerson, Bruce J; Beier, Richard A; Martin, Dennis L

    2015-11-01

    Frost injury patterns are commonly observed on the warm-season turfgrass species bermudagrass (Cynodon species Rich.), zoysiagrass (Zoysia species Willd.), and buffalograss [Bouteloua dactyloides (Nutt.) J.T. Columbus] in cool-temperate and subtropical zones. Qualitative observations of these injury patterns are presented and discussed. A model for the formation of such patterns based on thermal instability and convection of air is presented. The characteristic length scale of the observed frost pattern injury requires a temperature profile that decreases with height from the soil to the turfgrass canopy surface followed by an increase in temperature with height above the turfgrass canopy. This is justified by extending the earth temperature theory to include a turf layer with atmosphere above it. Then the theory for a thermally unstable layer beneath a stable region by Ogura and Kondo is adapted to a turf layer to include different parameter values for pure air, as well as for turf, which is treated as a porous medium. The earlier porous medium model of Thompson and Daniels proposed to explain frost injury patterns is modified to give reasonable agreement with observed patterns.

  15. Ground level air convection produces frost damage patterns in turfgrass

    NASA Astrophysics Data System (ADS)

    Ackerson, Bruce J.; Beier, Richard A.; Martin, Dennis L.

    2015-11-01

    Frost injury patterns are commonly observed on the warm-season turfgrass species bermudagrass ( Cynodon species Rich.), zoysiagrass ( Zoysia species Willd.), and buffalograss [ Bouteloua dactyloides (Nutt.) J.T. Columbus] in cool-temperate and subtropical zones. Qualitative observations of these injury patterns are presented and discussed. A model for the formation of such patterns based on thermal instability and convection of air is presented. The characteristic length scale of the observed frost pattern injury requires a temperature profile that decreases with height from the soil to the turfgrass canopy surface followed by an increase in temperature with height above the turfgrass canopy. This is justified by extending the earth temperature theory to include a turf layer with atmosphere above it. Then the theory for a thermally unstable layer beneath a stable region by Ogura and Kondo is adapted to a turf layer to include different parameter values for pure air, as well as for turf, which is treated as a porous medium. The earlier porous medium model of Thompson and Daniels proposed to explain frost injury patterns is modified to give reasonable agreement with observed patterns.

  16. 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.

  17. SOSIE: A pragmatic approach to the simulation of Broad Air Defense applied to the theater level

    NASA Astrophysics Data System (ADS)

    Tanter, A.; Deas, M.

    1995-01-01

    The SOSIE concept rests on an approach consisting of using existing simulation models of various systems and subsystems and automatically integrating them with minimum modifications within a center of simulation. The defense simulation against ballistic missiles on the theater level calls upon three levels of simulation: DIAMS; TACSIT, and SPOOK. DIAMS presents a fine level system simulation of weapon ground-to-air average carry, TACSIT presents a level of site defense (base air for example), and SPOOK deals with the theater level itself. SOSIE enables users to use the same detailed simulators, developed by an originator of weapon systems or information and communications, without having to know in detail the models of the simulation. Envisioned in the future is the integration of other models of simulations relating to the air-to-air combat, in particular, the networks of command, controls and communications.

  18. Quantification of ozone levels in indoor environments generated by ionization and ozonolysis air purifiers.

    PubMed

    Britigan, Nicole; Alshawa, Ahmad; Nizkorodov, Sergey A

    2006-05-01

    Indoor air purifiers are advertised as safe household products for health-conscious individuals, especially for those suffering from allergies and asthma. However, certain air purifiers produce ozone (O3) during operation, either intentionally or as a byproduct of air ionization. This is a serious concern, because O3 is a criteria air pollutant regulated by health-related federal and state standards. Several types of air purifiers were tested for their ability to produce ozone in various indoor environments at 40-50% relative humidity, including office rooms, bathrooms, bedrooms, and cars. O3 levels generated by personal wearable air purifiers were also tested. In many cases, O3 concentrations were well in excess of public and/or industrial safety levels established by U.S. Environmental Protection Agency, California Air Resources Board, and Occupational Safety and Health Administration. Simple kinetic equations were obtained that can predict the steady-state level of O3 in a room from the O3 emission rate of the air purifier and the first-order decay rate of O3 in the room. The additivity of O3 levels generated by independent O3 generators was experimentally demonstrated.

  19. Source levels of northern elephant seal vocalizations in-air

    NASA Astrophysics Data System (ADS)

    Insley, Stephen J.; Southall, Brandon L.

    2005-09-01

    Accurate measurements of vocalization sound-pressure levels are necessary to determine the acoustical active space of animals in natural and human-altered ambient noise conditions. Despite this basic need, such data are limited or nonexistent for most species. Our study characterized aerial ambient noise and vocalization source levels for northern elephant seals during the breeding season. Subjects were adult males, lactating females, and dependent offspring (pups) at An~o Nuevo State Reserve. Source level measurements were made using a Type 1 sound level meter and calibrated microphones on-axis: (1) at 1 m; (2) at several known distances (laser measured); and (3) simultaneously at 1 m and a second known distance. Concurrent ambient noise conditions were measured in situ (non-weighted 5 min Leq integrated averages) and recorded for later spectral analysis. Measurements were made at two sites, one relatively noisy and the other relatively quiet, to determine whether animals compensate for higher noise conditions by increasing source levels (Lombard effect). Results indicate a wide range in signal strength, particularly for adult males whose vocalization source levels appear to be correlated with dominance rank and related to ambient noise conditions. The Lombard effect was not observed for adult females or elephant seal pups.

  20. Implementing an Air Force Major Command-Level EMS

    DTIC Science & Technology

    2011-05-01

    n c e 7 Required ISO Elements for AF Organizational-Level EMS  MAJCOMs Are Required to Have the Following ISO Elements:  Scope and Policy...systems - Satisfy requirements of Execut ive Orders 13423 and 13514 and the I SO 14001 environmental management standard - Integrate ESOH tools and

  1. Stress and physiological, behavioral and performance patterns of children under varied air ion levels

    NASA Astrophysics Data System (ADS)

    Fornof, K. T.; Gilbert, G. O.

    1988-12-01

    The possibility that individual differences in reactivity to stressors are a major factor underlying discordant results reported for air ion studies prompted an investigation of response patterns in school children under both normal indoor air ion levels and moderately increased negative air ion levels (4000±500/cm3). It was hypothesized that the impact of stressors is reduced with high negative air ionization, and that resultant changes in stress effects would be differentially exhibited according to the children's normal degree of stimulus reactivity. A counter-balanced, replicative, withinssubject design was selected, and the subjects were 12 environmentally sensitive, 1st 4th grade school children. In addition to monitoring stress effects on activity level, attention span, concentration to task and conceptual performance, measures were also made of urinary 5-hydroxyindole acetic acid levels and skin resistance response (SRR) to determine if changes extended to the physiological state. The cold water test was used to add physical stress and enable calculations of Lacey's autonomic lability scores (ALS) as indicators of individual reactivity. The results show main effects for air ions on both physiological parameters, with 48% less change in %SRR ( P<0.01) and 46% less change in urinary 5-HIAA levels ( P<0.055) during negative air ions, indicating increased stress tolerance. Strong interactive effects for ALS x air ion condition appeared, with high and low ALS children reacting oppositely to negative air ions in measures of skin resistance level ( P<0.01), wrist activity ( P<0.01) and digit span backwards ( P<0.004). Thus individual differences in autonomic reactivity and the presence or absence of stressors appear as critical elements for internal validity, and in preventing consequent skewed results from obscuring progress in air ion research.

  2. Variations of the ambient dose equivalent rate in the ground level air.

    PubMed

    Lebedyte, M; Butkus, D; Morkŭnas, G

    2003-01-01

    The ambient dose equivalent rate is caused by ionizing radiation of radionuclides in the atmosphere and on the ground surface as well as by cosmic radiation. Seasonal and diurnal variations of the ambient dose equivalent rate (ADER) in the ground level air are influenced by the concentration of 222Rn daughters. The 222Rn concentration in the ground level atmosphere, in turn, depends on the rate of the 222Rn exhalation from soil and turbulent air mixing. Its diurnal and seasonal variations depend on meteorological conditions. The aim of this study is to estimate the influence of variations of the rate of the 222Rn exhalation from soil and its concentrations in the ground level air on variations of ADER in the ground level air, as well as the dependence of these parameters on meteorological conditions. The 222Rn diffusion coefficient and its exhalation rate in undisturbed loamy soil have been determined. The 222Rn concentration in the soil air and its concentration in the ground level air correlate inversely (correlation coefficient is r = -0.62). The main factors determining the 222Rn exhalation from soil are: the soil temperature (r = 0.64), the difference in temperature of soil and air (r = 0.57), and the precipitation amount (r = 0.50). The intensity of gamma radiation in the ground level air is mostly related to the 222Rn concentration in the air (r = 0.62), while the effect of the exhalation rate from soil is relatively low (r = 0.36). It has been shown that ADER due to 222Rn progeny causes only 7-16% of the total ADER and influences its variation. The comparison of variations of ADER due to 222Rn progeny and the total ADER during several years shows that these parameters correlate positively.

  3. Use of an indoor air quality model (IAQM) to estimate indoor ozone levels.

    PubMed

    Hayes, S R

    1991-02-01

    Currently, outdoor ozone levels in many U.S. cities exceed the primary health-based national ambient air quality standard. While outdoor ozone levels are an important measure of the severity of those exceedances, people typically spend more than 80 percent of their time indoors, where ozone levels are lower. Indoor ozone levels range from 10 to 80 percent of outdoor levels, with many people receiving a substantial portion of their ozone exposure while indoors. This paper uses an indoor air quality model (IAQM) to estimate indoor ozone levels by microenvironment type (home, office, and vehicle) and configuration (windows open, windows closed, older construction, weatherized, and air conditioned). The formulation of IAQM is discussed, along with specification of model parameters for ozone. The multicompartment version of IAQM is described, with a single-compartment version used for the analyses. IAQM-calculated ozone indoor-outdoor ratios compare well with research-reported values. Results indicate that ozone peak-concentration indoor-outdoor ratios range as follows: home--0.65 (windows open), 0.36 (air conditioned), 0.23 (typical construction, windows closed), and 0.05 (energy-efficient construction, windows closed); office--0.82 (heating, ventilation and air conditioning systems supplying 100 percent outdoor air), 0.60 (typical HVAC), and 0.32 (energy-efficient HVAC); and vehicle--0.41 (85 mph), 0.33 (55 mph), and 0.21 (10 mph). Analysis results are presented to characterize IAQM's sensitivity to assumed model parameters.

  4. Tissue kerma vs distance relationships for initial nuclear radiation from the atomic devices detonated over Hiroshima and Nagasaki

    SciTech Connect

    Kerr, G.D.; Pace, J.V. III; Scott, W.H. Jr.

    1983-06-01

    Initial nuclear radiation is comprised of prompt neutrons and prompt primary gammas from an exploding nuclear device, prompt secondary gammas produced by neutron interactions in the environment, and delayed neutrons and delayed fission-product gammas from the fireball formed after the nuclear device explodes. These various components must all be considered in establishing tissue kerma vs distance relationships which describe the decrease of initial nuclear radiation with distance in Hiroshima and in Nagasaki. The tissue kerma at ground evel from delayed fission-product gammas and delayed neutrons was investigated using the NUIDEA code developed by Science Applications, Inc. This code incorporates very detailed models which can take into account such features as the rise of the fireball, the rapid radioactive decay of fission products in it, and the perturbation of the atmosphere by the explosion. Tissue kerma vs distance relationships obtained by summing results of these current state-of-the-art calculations will be discussed. Our results clearly show that the prompt secondary gammas and delayed fission-product gammas are the dominant components of total tissue kerma from initial nuclear radiation in the cases of the atomic (or pure-fission) devices detonated over Hiroshima and Nagasaki.

  5. 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

  6. Microbial counts and particulate matter levels in roadside air samples under skytrain stations, Bangkok, Thailand.

    PubMed

    Luksamijarulkul, Pipat; Kongtip, Pornpimol

    2010-05-01

    In conditions with heavy traffic and crowds of people on roadside areas under skytrain stations in Bangkok, the natural air ventilation may be insufficient and air quality may be poor. A study of 350 air samples collected from the roadside, under skytrain stations in Bangkok, was carried out to assess microbial counts (210 air samples) and particulate matter (PM10) levels (140 samples). The results reveal the mean +/- standard deviation bacterial counts and fungal counts were 406.8 +/- 302.7 cfu/m3 and 128.9 +/- 89.7 cfu/m3, respectively. The PM10 level was 186.1 +/- 188.1 microg/m3. When compared to recommended levels, 4.8% of air samples (10/210 samples) had bacterial counts more than recommended levels (> 1,000 cfu/ m3) and 27.1% (38/140 samples) had PM10 levels more than recommended levels (> 120 microg/m3). These may affect human health, especially of street venders who spend most of their working time in these areas.

  7. BOREAS AFM-5 Level-2 Upper Air Network Standard Pressure Level Data

    NASA Technical Reports Server (NTRS)

    Barr, Alan; Hrynkiw, Charmaine; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS AFM-5 team collected and processed data from the numerous radiosonde flights during the project. The goals of the AFM-05 team were to provide large-scale definition of the atmosphere by supplementing the existing AES aerological network, both temporally and spatially. This data set includes basic upper-air parameters interpolated at 0.5 kiloPascal increments of atmospheric pressure from data collected from the network of upper-air stations during the 1993, 1994, and 1996 field campaigns over the entire study region. The data are contained in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  8. [Study on feasible emission control level of air pollutions for cement industry ].

    PubMed

    Ren, Chun; Jiang, Mei; Zou, Lan; Li, Xiao-qian; Wei, Yu-xia; Zhao, Guo-hua; Zhang, Guo-ning

    2014-09-01

    The revised National Emission Standard of Air Pollutions for Cement Industry has been issued, which will be effective for the new enterprises and the existing enterprises on Mar. 1st, 2014 and July 1st, 2015, respectively. In the process of revision, the key technical issues on determination of standard limits was how to determine the feasible emission control level of air pollutions. Feasible emission control requirements were put forward, according to air pollutants emission, technologies, environmental management requirements and foreign standards, etc. The main contents of the revised standard include expanding the scope of application, increasing the pollutants, improving the particulate and NO emissions control level, and increasing special emission limits applied to key areas of air pollutants. The standard will become the gripper of pollution prevention, total emission reduction, structural adjustment and optimization of the layout, and will promote scientific and technical progression for the cement industry.

  9. Dependence of radon levels in Postojna Cave on outside air temperature

    NASA Astrophysics Data System (ADS)

    Gregorič, A.; Zidanšek, A.; Vaupotič, J.

    2011-05-01

    Postojna Cave is the largest of 21 show caves in Slovenia. The radon concentration there was measured continuously in the Great Mountain hall from July 2005 to October 2009 and ranged from about 200 Bq m-3 in winter to about 3 kBq m-3 in summer. The observed seasonal pattern of radon concentration is governed by air movement due to the difference in external and internal air densities, controlled mainly by air temperature. The cave behaves as a large chimney and in the cold period, the warmer cave air is released vertically through cracks and fissures to the colder outside atmosphere, enabling the inflow of fresh air with low radon levels. In summer the ventilation is minimal or reversed and the air flows from the higher to the lower openings of the cave. Our calculations have shown that the effect of the difference between outside and cave air temperatures on radon concentration is delayed for four days, presumably because of the distance of the measurement point from the lower entrance (ca. 2 km). A model developed for predicting radon concentration on the basis of outside air temperature has been checked and found to be successful.

  10. Search for tachyons associated with extensive air showers in the ground level cosmic radiation

    NASA Technical Reports Server (NTRS)

    Masjed, H. F.; Ashton, F.

    1985-01-01

    Events detected in a shielded plastic scintillation counter occurring in the 26 microsec preceding the arrival of an extensive air shower at ground level with local electron density or = 20 m to the -2 power and the 240 microsec after its arrival have been studied. No significant excess of events (tachyons) arriving in the early time domain have been observed in a sample of 11,585 air shower triggers.

  11. Urban air quality and carboxyhemoglobin levels in a group of traffic policemen.

    PubMed

    Bono, R; Piccioni, P; Traversi, D; Degan, R; Grosa, M; Bosello, G; Gilli, G; Arossa, W; Bugiani, M

    2007-04-15

    Toxicological potential of carbon monoxide (CO) on humans is well known. Nevertheless, CO is still considered as a useful marker to detect some environmental and occupational human risk factors typical of cities. The role played by traffic pollution, indoor air quality in offices and tobacco smoke on the expression of carboxyhemoglobin (COHb%) levels was investigated in a large group of traffic policemen in Torino city (North-Western Italy). At the end of the working shift, 228 policemen responded to a questionnaire, weight and height recorded, urine spot samples collected to measure cotinine as biomarker of tobacco smoke exposure, and an arterial blood sample was taken to measure COHb levels. Data of outdoor urban air-CO were collected and to each subject a "CO outdoor air measurement" was related to his/her COHb level. Considering the annual trend of air-CO pollution from 2002 to 2004, one can assume that a general improvement of air quality in Torino was evident. Taking into account the environments where policemen work (urban outdoor and indoor), and analyzing their COHb% content, the traffic-congested areas, and, in general, the outdoor urban environment were equally risky as offices. Furthermore, if compared to CO arising from traffic-congested areas or other outdoor environments, the traffic policemen in Torino city demonstrate COHb% levels largely due to smoking habits.

  12. The Effect of Air Tourniquet on Interleukin-6 Levels in Total Knee Arthroplasty

    PubMed Central

    Tsunoda, Kenji; Sonohata, Motoki; Kugisaki, Hajime; Someya, Shinsuke; Honke, Hidefumi; Komine, Mitsunori; Izumi, Masataka; Ide, Shuya; Mawatari, Masaaki

    2017-01-01

    Background: Air tourniquet-induced skeletal muscle injury increases the concentrations of some cytokines such as interleukin-6 (IL-6) in plasma. However, the effect of an air tourniquet on the IL-6 concentrations after total knee arthroplasty (TKA) is unclear. We therefore investigated the impact of tourniquet-induced ischemia and reperfusion injury in TKA using the IL-6 level as an index. Methods: Ten patients with primary knee osteoarthrosis who underwent unilateral TKA without an air tourniquet were recruited (Non-tourniquet group). We also selected 10 age- and sex-matched control patients who underwent unilateral TKA with an air tourniquet (Tourniquet group). Venous blood samples were obtained at 3 points; before surgery, 24 h after surgery, and 7 days after surgery. The following factors were compared between the two groups; IL-6, C-reactive protein (CRP), creatine phosphokinase (CPK), the mean white blood cell (WBC) counts, and the maximum daily body temperatures. Results: The IL-6 level at 24 h after surgery was significantly higher than that at any other point (p<0.01). No significant differences were observed in the WBC count, the body temperature, or the CRP, CPK, or IL-6 levels of the two groups at any of the time points. Conclusion: The effect of ischemia and reperfusion due to the use of an air tourniquet on increasing the IL-6 level was much smaller than that induced by surgical stress in TKA. PMID:28217217

  13. GSOD Based Daily Global Mean Surface Temperature and Mean Sea Level Air Pressure (1982-2011)

    SciTech Connect

    Xuan Shi, Dali Wang

    2014-05-05

    This data product contains all the gridded data set at 1/4 degree resolution in ASCII format. Both mean temperature and mean sea level air pressure data are available. It also contains the GSOD data (1982-2011) from NOAA site, contains station number, location, temperature and pressures (sea level and station level). The data package also contains information related to the data processing methods

  14. Determination of radionuclide concentrations in ground level air using the ASS-500 high volume sampler

    SciTech Connect

    Frenzel, E.; Arnold, D.; Wershofen, H.

    1996-06-01

    A method for determination of radionuclide concentrations in air aerosol samples collected by the high volume aerosol sampler ASS-500 was elaborated. The aerosol sampling station ASS-500 is a Stand alone, all-weather proofed instrument. It is designed for representative sampling of airborne radionuclides from ground level air at a height of about 1.5 m above ground level. The ASS-500 station enables continuous air monitoring both normal and emergency Situations. The collection of aerosols on the Petrianov FPP-15-1.5 type filter out of an air volume of about 100,000 m{sup 3} (sampling period 1 wk) or of about 250,000 m{sup 3} (sampling period 3 wk) admits accurate spectrometric low level measurements of natural and artificial radionuclides. The achieved detection limit is 0.5 {mu}Bq m{sup -3} and 0.2 {mu}Bq m{sup -3} for {sup 137}Cs, respectively. A new developed air flow Meter system allows to enhance the collected air volume to about 150,000 m{sup 3} per week and lowers the detection limit to <0.4 {mu}Bq m{sup -3} for {sup 137}Cs for weekly collected aerosol samples. In Poland the CLOR uses 9 Stations ASS-500 at different sites as atmospheric radioactivity control system. On the basis of spectrometric measurements of natural and artificial radionuclides in the collected aerosol samples at the different sites, CLOR establishes a weekly report about the radiological situation at Poland for responsible authorities. The very low achievable detection limit of the Station ASS-500 due 10 the high air flow fate and the long possible sampling period were the key argument for other government radiation protection authorities in Europe to introduce the Station ASS-500 into their low level radionuclide atmospheric monitoring programs (Austria, Belarus, France, Germany, Iceland, Spain, Switzerland, Ukraine).

  15. Air levels of carcinogenic polycyclic aromatic hydrocarbons after the World Trade Center disaster.

    PubMed

    Pleil, Joachim D; Vette, Alan F; Johnson, Brent A; Rappaport, Stephen M

    2004-08-10

    The catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, created an immense dust cloud followed by fires that emitted soot into the air of New York City (NYC) well into December. The subsequent cleanup used diesel equipment that further polluted the air until the following June. The particulate air pollutants contained mutagenic and carcinogenic polycyclic aromatic hydrocarbons (PAHs). By using an assay developed for archived samples of fine particles, we measured nine PAHs in 243 samples collected at or near Ground Zero from September 23, 2001, to March 27, 2002. Based on temporal trends of individual PAH levels, we differentiated between fire and diesel sources and predicted PAH levels between 3 and 200 d after the disaster. Predicted PAH air concentrations on September 14, 2001, ranged from 1.3 to 15 ng/m(3); these values are among the highest reported from outdoor sources. We infer that these high initial air concentrations resulted from fires that rapidly diminished over 100 d. Diesel sources predominated for the next 100 d, during which time PAH levels declined slowly to background values. Because elevated PAH levels were transient, any elevation in cancer risk from PAH exposure should be very small among nonoccupationally exposed residents of NYC. However, the high initial levels of PAHs may be associated with reproductive effects observed in the offspring of women who were (or became) pregnant shortly after September 11, 2001. Because no PAH-specific air sampling was conducted, this work provides the only systematic measurements, to our knowledge, of ambient PAHs after the WTC disaster.

  16. Australia’s first national level quantitative environmental justice assessment of industrial air pollution

    NASA Astrophysics Data System (ADS)

    Chakraborty, Jayajit; Green, Donna

    2014-04-01

    This study presents the first national level quantitative environmental justice assessment of industrial air pollution in Australia. Specifically, our analysis links the spatial distribution of sites and emissions associated with industrial pollution sources derived from the National Pollution Inventory, to Indigenous status and social disadvantage characteristics of communities derived from Australian Bureau of Statistics indicators. Our results reveal a clear national pattern of environmental injustice based on the locations of industrial pollution sources, as well as volume, and toxicity of air pollution released at these locations. Communities with the highest number of polluting sites, emission volume, and toxicity-weighted air emissions indicate significantly greater proportions of Indigenous population and higher levels of socio-economic disadvantage. The quantities and toxicities of industrial air pollution are particularly higher in communities with the lowest levels of educational attainment and occupational status. These findings emphasize the need for more detailed analysis in specific regions and communities where socially disadvantaged groups are disproportionately impacted by industrial air pollution. Our empirical findings also underscore the growing necessity to incorporate environmental justice considerations in environmental planning and policy-making in Australia.

  17. Some insights into the relationship between urban air pollution and noise levels.

    PubMed

    Kim, Ki-Hyun; Ho, Duy Xuan; Brown, Richard J C; Oh, J-M; Park, Chan Goo; Ryu, In Cheol

    2012-05-01

    The relationship between noise and air pollution was investigated in eight different districts across Seoul, Korea, between September and November 2010. The noise levels in each district were measured at both roadside and non-roadside locations. It was found that the maximum levels of noise were generally at frequencies of around 1000 Hz. The equivalent noise levels (L(eq)), over all districts, averaged 61.4 ± 7.36 dB which is slightly lower than the noise guidelines set by the World Health Organization (WHO) of 70 dB for industrial, commercial, traffic, and outdoor areas. Comparison of L(eq) levels in each district consistently indicates that noise levels are higher at roadside sites than non-roadside sites. In addition the relative dominance of noise during daytime as compared to nighttime was also apparent. Moreover, the results of an analysis relating sound levels with air pollutant levels indicate strongly that the correlation between these two parameters is the strongest at roadside sites (relative to non-roadside sites) and during nighttime (relative to daytime). The results of our data analysis point to a positive, but complex, correlation between noise levels and air pollution.

  18. Decline of Ambient Air Pollution Levels and Improved Respiratory Health in Swiss Children

    PubMed Central

    Bayer-Oglesby, Lucy; Grize, Leticia; Gassner, Markus; Takken-Sahli, Kathy; Sennhauser, Felix H.; Neu, Urs; Schindler, Christian; Braun-Fahrländer, Charlotte

    2005-01-01

    The causality of observed associations between air pollution and respiratory health in children is still subject to debate. If reduced air pollution exposure resulted in improved respiratory health of children, this would argue in favor of a causal relation. We investigated whether a rather moderate decline of air pollution levels in the 1990s in Switzerland was associated with a reduction in respiratory symptoms and diseases in school children. In nine Swiss communities, 9,591 children participated in cross-sectional health assessments between 1992 and 2001. Their parents completed identical questionnaires on health status and covariates. We assigned to each child an estimate of regional particles with an aerodynamic diameter < 10 μg/m3 (PM10) and determined change in PM10 since the first survey. Adjusted for socioeconomic, health-related, and indoor factors, declining PM10 was associated in logistic regression models with declining prevalence of chronic cough [odds ratio (OR) per 10-μg/m3 decline = 0.65, 95% confidence interval (CI), 0.54–0.79], bronchitis (OR = 0.66; 95% CI, 0.55–0.80), common cold (OR = 0.78; 95% CI, 0.68–0.89), nocturnal dry cough (OR = 0.70; 95% CI, 0.60–0.83), and conjunctivitis symptoms (OR = 0.81; 95% CI, 0.70–0.95). Changes in prevalence of sneezing during pollen season, asthma, and hay fever were not associated with the PM10 reduction. Our findings show that the reduction of air pollution exposures contributes to improved respiratory health in children. No threshold of adverse effects of PM10 was apparent because we observed the beneficial effects for relatively small changes of rather moderate air pollution levels. Current air pollution levels in Switzerland still exceed limit values of the Swiss Clean Air Act; thus, children’s health can be improved further. PMID:16263523

  19. Decline of ambient air pollution levels and improved respiratory health in Swiss children.

    PubMed

    Bayer-Oglesby, Lucy; Grize, Leticia; Gassner, Markus; Takken-Sahli, Kathy; Sennhauser, Felix H; Neu, Urs; Schindler, Christian; Braun-Fahrländer, Charlotte

    2005-11-01

    The causality of observed associations between air pollution and respiratory health in children is still subject to debate. If reduced air pollution exposure resulted in improved respiratory health of children, this would argue in favor of a causal relation. We investigated whether a rather moderate decline of air pollution levels in the 1990s in Switzerland was associated with a reduction in respiratory symptoms and diseases in school children. In nine Swiss communities, 9,591 children participated in cross-sectional health assessments between 1992 and 2001. Their parents completed identical questionnaires on health status and covariates. We assigned to each child an estimate of regional particles with an aerodynamic diameter < 10 microg/m3 (PM10) and determined change in PM10 since the first survey. Adjusted for socioeconomic, health-related, and indoor factors, declining PM10 was associated in logistic regression models with declining prevalence of chronic cough [odds ratio (OR) per 10-microg/m3 decline = 0.65, 95% confidence interval (CI), 0.54-0.79], bronchitis (OR = 0.66; 95% CI, 0.55-0.80), common cold (OR = 0.78; 95% CI, 0.68-0.89), nocturnal dry cough (OR = 0.70; 95% CI, 0.60-0.83), and conjunctivitis symptoms (OR = 0.81; 95% CI, 0.70-0.95). Changes in prevalence of sneezing during pollen season, asthma, and hay fever were not associated with the PM10 reduction. Our findings show that the reduction of air pollution exposures contributes to improved respiratory health in children. No threshold of adverse effects of PM10 was apparent because we observed the beneficial effects for relatively small changes of rather moderate air pollution levels. Current air pollution levels in Switzerland still exceed limit values of the Swiss Clean Air Act; thus, children's health can be improved further.

  20. Microorganism levels in air near spray irrigation of municipal waste water: The Lubbock Infection Surveillance Study

    SciTech Connect

    Camann, D.E.; Moore, B.E.; Harding, H.J.; Sorber, C.A.

    1988-01-01

    The Lubbock Infection Surveillance Study (LISS) investigated possible adverse effects on human health from slow-rate land application of municipal wastewater. Extensive air sampling was conducted to characterize the irrigation site as a source of infectious microbial aerosols. Spray irrigation of poor-quality waste water received directly from the treatment plant significantly elevated air densities of fecal coliforms, fecal streptococci, mycobacteria, and coliphage above ambient background levels for at least 200 m downwind. Enteroviruses were repeatedly recovered at 44 to 60 m downwind at a higher level (geometric mean = 0.05 pfu/m3) than observed at other waste water aerosol sites in the U.S. and in Israel. Waste water storage in reservoirs reduced downwind air densities of indicator organisms by two orders of magnitude.

  1. K{sub Air} and H*(10) Rate Constants for Gamma Emitters

    SciTech Connect

    Vega-Carrillo, H. R.; Juarez, R. Rodriguez; Manzanares-Acuna, E.; Davila, V. M. Hernandez; Mercado, G. A.

    2008-08-11

    Monte Carlo calculations have been carried out to estimate the Air Kerma rate constant and the Ambient dose equivalent rate constant for 139 monoenergetic photon sources. The factor that relates activity to air kerma rate or to ambient dose equivalent is useful to estimate the dose from a photon emitter source. Here 139 point-like and monoenergetic gamma-ray sources, ranging from 0.01 to 10 MeV were utilized in Monte Carlo calculations to estimate both gamma factors. These factors were utilized to calculate the air kerma-and-ambient dose equivalent rate constants for {sup 137}Cs-{sup 137m}Ba, {sup 198}Au, {sup 60}Co, and {sup 131}I, whose values were compared with those published in the literature.

  2. Indoor air quality levels in a University Hospital in the Eastern Province of Saudi Arabia

    PubMed Central

    El-Sharkawy, Mahmoud F.; Noweir, Mohamed E. H.

    2014-01-01

    Aim of the Study: The complex hospital environment requires special attention to ensure a healthy indoor air quality (IAQ) to protect patients and healthcare workers against hospital-acquired infections and occupational diseases. Poor hospital IAQ may cause outbreaks of building-related illness such as headaches, fatigue, eye, and skin irritations, and other symptoms. The general objective for this study was to assess IAQ inside a large University hospital at Al-Khobar City in the Eastern Province of Saudi Arabia. Materials and Methods: Different locations representing areas where most activities and tasks are performed were selected as sampling points for air pollutants in the selected hospital. In addition, several factors were studied to determine those that were most likely to affect the IAQ levels. The temperature and relative percent humidity of different air pollutants were measured simultaneously at each location. Results: The outdoor levels of all air pollutant levels, except volatile organic compounds (VOCs), were higher than the indoor levels which meant that the IAQ inside healthcare facilities (HCFs) were greatly affected by outdoor sources, particularly traffic. The highest levels of total suspended particulates (TSPs) and those less than 10 microns (PM10) inside the selected hospital were found at locations that are characterized with m4ore human activity. Conclusions: Levels of particulate matter (both PM10 and TSP) were higher than the Air Quality Guidelines (AQGs). The highest concentrations of the fungal species recorded were Cladosporium and Penicillium. Education of occupants of HCF on IAQ is critical. They must be informed about the sources and effects of contaminants and the proper operation of the ventilation system. PMID:24696632

  3. Air-powder polishing on self-ligating brackets after clinical use: effects on debris levels

    PubMed Central

    Aragón, Mônica L. S. Castro; Lima, Leandro Santiago; Normando, David

    2016-01-01

    ABSTRACT Introduction: Debris buildup on brackets and arch surfaces is one of the main factors that can influence the intensity of friction between bracket and orthodontic wire. Objective: This study sought to evaluate the effect of air-powder polishing cleaning on debris levels of self-ligating ceramic brackets at the end of orthodontic treatment, compared to the behavior of conventional brackets. Methods: Debris levels were evaluated in metal conventional orthodontic brackets (n = 42) and ceramic self-ligating brackets (n = 42) on canines and premolars, arranged in pairs. There were brackets with and without air-powder polishing. At the end of orthodontic treatment, a hemiarch served as control and the contralateral hemiarch underwent prophylaxis with air-powder polishing. Debris buildup in bracket slots was assessed through images, and Wilcoxon test was used to analyze the results. Results: The median debris levels were statistically lower in the conventional metal brackets compared to self-ligating ones (p = 0.02), regarding brackets not submitted to air-powder polishing. Polishing significantly reduced debris buildup to zero in both systems, without differences between groups. Conclusions: Ceramic self-ligating brackets have a higher debris buildup in comparison to conventional metal brackets in vivo, but prophylaxis with sodium bicarbonate jet was effective in reducing debris levels in self-ligating and also in conventional brackets. PMID:27901234

  4. Trends in motor neuron disease: association with latitude and air lead levels in Spain.

    PubMed

    Santurtún, Ana; Villar, Alejandro; Delgado-Alvarado, Manuel; Riancho, Javier

    2016-08-01

    Motor neuron diseases (MND) are a group of disorders characterized by motor neuron degeneration. Among them, amyotrophic lateral sclerosis (ALS) is by far the most common in adulthood. This paper assesses the trend and geographical pattern in MND incidence in Spain and the possible air lead levels effect on this pathology. To confirm this concept, we performed a retrospective analysis of the deaths due to MND in Spain during 2000 and 2013, determined the geographical differences, and explored the relationship between MND and the air levels of lead. Overall, between 2000 and 2013, 11,355 people died in Spain because of MND. Disease mortality significantly increased in recent years (2007-2013) when compared with the first time of the period. Spearman's rank correlation coefficient also showed a statistically significant positive trend (CC = 0.824, p = 0.0002). Among people over 65 years, mortality rates were higher in Northern provinces. Moreover, we found a significant association of MND mortality with higher air lead levels (CC = 0.457, p = 0.01). Our study confirms that MND mortality is increasing in Spain, with a significant latitude gradient, which suggests an important role of environmental exposures. This ecological study suggests that air lead levels may be implicated in ALS pathogenesis.

  5. Surveillance programme on dioxin levels in ambient air sites in Catalonia (Spain).

    PubMed

    Abad, Esteban; Caixach, Josep; Rivera, Josep; Gustems, Lluís; Massagué, Guillem; Puig, Oriol

    2002-11-01

    As part of a survey programme conducted by the Environment Department of the Autonomous Government of Catalonia in collaboration with the Spanish Council for Scientific Research (CSIC), dioxin concentrations in ambient air were measured in the four provinces of Catalonia (Spain). The study was also performed with the intention of providing data as a basis for future monitoring and evaluation of temporal trends in ambient air. Thus, 91 samples were collected in 25 different sites (rural, urban, suburban and industrial) between 1994 and 2000. The levels revealed a variable content of PCDDs/PCDFs depending both on the area and the contamination source. In particular, industrial areas presented levels ranging from 18 to 954 fg I-TEQ/m3. However, findings in urban and suburban sites varied between 13 and 357 fg I-TEQ/m3. As expected, the lowest levels were found in rural areas with levels between 5 and 125 fg I-TEQ/m3.

  6. Precipitation and Air Temperature Impact on Seasonal Variations of Groundwater Levels

    NASA Astrophysics Data System (ADS)

    Vitola, Ilva; Vircavs, Valdis; Abramenko, Kaspars; Lauva, Didzis; Veinbergs, Arturs

    2012-12-01

    The aim of this study is to clarify seasonal effects of precipitation and temperature on groundwater level changes in monitoring stations of the Latvia University of Agriculture - Mellupīte, Bērze and Auce. Groundwater regime and level fluctuations depend on climatic conditions such as precipitation intensity, evapotranspiration, surface runoff and drainage, as well as other hydrological factors. The relationship between precipitation, air temperature and groundwater level fluctuations could also lead and give different perspective of possible changes in groundwater quality. Using mathematical statistics and graphic-analytic methods it is concluded that autumn and winter precipitation has the dominant impact on groundwater level fluctuations, whereas spring and summer season fluctuations are more dependent on the air temperature.

  7. 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

  8. Benzene levels in ambient air and breath of smokers and nonsmokers in urban and pristine environments

    SciTech Connect

    Wester, R.C.; Maibach, H.I.; Gruenke, L.D.; Craig, J.C.

    1986-01-01

    Benzene levels in human breath and in ambient air were compared in the urban area of San Francisco (SF) and in a more remote coastal pristine setting of Stinson Beach, Calif. (SB). Benzene analysis was done by gas chromatography-mass spectroscopy (GC-MS). Ambient benzene levels were sevenfold higher in SF (2.6 +/- 1.3 ppb, n = 25) than SB (0.38 +/- 0.39 ppb, n = 21). In SF, benzene in smokers' breath (6.8 +/- 3.0 ppb) was greater than in nonsmokers' breath (2.5 +/- 0.8 ppb) and smokers' ambient air (3.3 +/- 0.8 ppb). In SB the same pattern was observed: benzene in smokers' breath was higher than in nonsmokers' breath and ambient air. Benzene in SF nonsmokers' breath was greater than in SB nonsmokers' breath. Marijuana-only smokers had benzene breath levels between those of smokers and nonsmokers. There was little correlation between benzene in breath and number of cigarettes smoked, or with other benzene exposures such as diet. Of special interest was the finding that benzene in breath of SF nonsmokers (2.5 +/- 0.8 ppb) was greater than that in nonsmokers ambient air (1.4 +/- 0.1 ppb). The same was true in SB, where benzene in nonsmokers breath was greater than ambient air (1.8 +/- 0.2 ppb versus 1.0 +/- 0.1 ppb on d 1 and 1.3 +/- 0.3 ppb versus 0.23 +/- 0.18 ppb on d 2). This suggests an additional source of benzene other than outdoor ambient air.

  9. On evaluating compliance with air pollution levels 'not to be exceeded more than once per year'

    NASA Technical Reports Server (NTRS)

    Neustadter, H. E.; Sidik, S. M.

    1974-01-01

    The point of view taken is that the Environmental Protection Agency (EPA) Air Quality Standards (AQS) represent conditions which must be made to exist in the ambient environment. The statistical techniques developed should serve as tools for measuring the closeness to achieving the desired quality of air. It is shown that the sampling frequency recommended by EPA is inadequate to meet these objectives when the standard is expressed as a level not to be exceeded more than once per year and sampling frequency is once every three days or less frequent.

  10. 77 FR 66595 - U.S. Air Force Broadcast of Consent Order, and Determination of Interest Level for a United...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-06

    ... Under Secretary of the Air Force (Space). ACTION: Publicize Consent Order, and Determine Level of... Deputy Under Secretary of the Air Force (Space), as the Compliance Officer under the Federal Trade... current Compliance Officer is the Deputy Under Secretary of the Air Force (Space), Mr. Richard...

  11. Influence of air exposure and storage condition on serum ionized magnesium level.

    PubMed

    Baek, E J; Park, I K

    2005-01-01

    The aim of this study was to evaluate whether reporting serum level of ionized magnesium (iMg) is appropriate when affected by various conditions such as exposure to air and delayed measurement. Serum levels of pH, iMg and normalized magnesium (nMg, normalized or adjusted concentration of iMg to pH 7.40) from 28 inpatients were measured at intervals of 3 min after exposing the samples to air at room temperature. Serum from 30 inpatients was stored in closed tubes at 4 degrees C and -20 degrees C and iMg and nMg levels were measured after 2 days. It was found that serum iMg and nMg concentrations exposed to air were decreased by 0.0023 mmol/l and 0.0001 mmol/l per minute, respectively. nMg did not display any significant changes compared with iMg at 0 min, whereas iMg showed significant changes, which exceeded between-day precision. For the stored serum, only iMg of serum at -20 degrees C showed no statistically significant changes (p = 0.169). It is concluded that to report the result as iMg, the sample should be kept anaerobically, and if exposed to air, the result should be reported as nMg. For storage, iMg of serum kept anaerobically at -20 degrees C is reliable.

  12. Making air quality indices comparable--assessment of 10 years of air pollutant levels in western Europe.

    PubMed

    Lokys, Hanna Leona; Junk, Jürgen; Krein, Andreas

    2015-01-01

    To address the incomparability of the large number of existing air quality indices, we propose a new normalization method that is suited to directly compare air quality indices based on the common European World Health Organization (WHO) air quality guidelines for NO2, O3, and PM10. Using this method, we compared three air quality indices based on the European guidelines, related them to another air quality index based on the relative risk concept, and used them to assess the air quality and its trends in northwest central Europe. The average air quality in the area of investigation is below the recommended European guidelines. The majority of index values exceeding this threshold are caused by PM10, which is also, in most cases, responsible for the degrading trends in air quality. Eleven out of 29 stations tested showed significant trends, of which eight indicated trends towards better air quality.

  13. A proposed methodology for the assessment of arsenic, nickel, cadmium and lead levels in ambient air.

    PubMed

    Santos, Germán; Fernández-Olmo, Ignacio

    2016-06-01

    Air quality assessment, required by the European Union (EU) Air Quality Directive, Directive 2008/50/EC, is part of the functions attributed to Environmental Management authorities. Based on the cost and time consumption associated with the experimental works required for the air quality assessment in relation to the EU-regulated metal and metalloids, other methods such as modelling or objective estimation arise as competitive alternatives when, in accordance with the Air Quality Directive, the levels of pollutants permit their use at a specific location. This work investigates the possibility of using statistical models based on Partial Least Squares Regression (PLSR) and Artificial Neural Networks (ANNs) to estimate the levels of arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb) in ambient air and their application for policy purposes. A methodology comprising the main steps that should be taken into consideration to prepare the input database, develop the model and evaluate their performance is proposed and applied to a case of study in Santander (Spain). It was observed that even though these approaches present some difficulties in estimating the individual sample concentrations, having an equivalent performance they can be considered valid for the estimation of the mean values - those to be compared with the limit/target values - fulfilling the uncertainty requirements in the context of the Air Quality Directive. Additionally, the influence of the consideration of input variables related to atmospheric stability on the performance of the studied statistical models has been determined. Although the consideration of these variables as additional inputs had no effect on As and Cd models, they did yield an improvement for Pb and Ni, especially with regard to ANN models.

  14. Background information on sources of low-level radionuclide emissions to air

    SciTech Connect

    Corbit, C.D.; Herrington, W.N.; Higby, D.P.; Stout, L.A.; Corley, J.P.

    1983-09-01

    This report provides a general description and reported emissions for eight low-level radioactive source categories, including facilties that are licensed by the Nuclear Regulatory Commission (NRC) and Agreement States, and non-Department of Energy (DOE) federal facilities. The eight categories of low-level radioactive source facilities covered by this report are: research and test reactors, accelerators, the radiopharmaceutical industry, source manufacturers, medical facilities, laboratories, naval shipyards, and low-level commercial waste disposal sites. Under each category five elements are addressed: a general description, a facility and process description, the emission control systems, a site description, and the radionuclides released to air (from routine operations).

  15. Techno-Economic Analysis of Indian Draft Standard Levels for RoomAir Conditioners

    SciTech Connect

    McNeil, Michael A.; Iyer, Maithili

    2007-03-01

    The Indian Bureau of Energy Efficiency (BEE) finalized its first set of efficiency standards and labels for room air conditioners in July of 2006. These regulations followed soon after the publication of levels for frost-free refrigerators in the same year. As in the case of refrigerators, the air conditioner program introduces Minimum Efficiency Performance Standards (MEPS) and comparative labels simultaneously, with levels for one to five stars. Also like the refrigerator program, BEE defined several successive program phases of increasing stringency. In support of BEE's refrigerator program, Lawrence Berkeley National Laboratory (LBNL) produced an analysis of national impacts of standards in collaboration with the Collaborative Labeling and Standards Program (CLASP). That analysis drew on LBNL's experience with standards programs in the United States, as well as many other countries. Subsequently, as part of the process for setting optimal levels for air conditioner regulations, CLASP commissioned LBNL to provide support to BEE in the form of a techno-economic evaluation of air conditioner efficiency technologies. This report describes the methodology and results of this techno-economic evaluation. The analysis consists of three components: (1) Cost effectiveness to consumers of efficiency technologies relative to current baseline. (2) Impacts on the current market from efficiency regulations. (3) National energy and financial impacts. The analysis relied on detailed and up-to-date technical data made available by BEE and industry representatives. Technical parameters were used in conjunction with knowledge about air conditioner use patterns in the residential and commercial sectors, and prevailing marginal electricity prices, in order to give an estimate of per-unit financial impacts. In addition, the overall impact of the program was evaluated by combining unit savings with market forecasts in order to yield national impacts. LBNL presented preliminary results

  16. Combining regression analysis and air quality modelling to predict benzene concentration levels

    NASA Astrophysics Data System (ADS)

    Vlachokostas, Ch.; Achillas, Ch.; Chourdakis, E.; Moussiopoulos, N.

    2011-05-01

    State of the art epidemiological research has found consistent associations between traffic-related air pollution and various outcomes, such as respiratory symptoms and premature mortality. However, many urban areas are characterised by the absence of the necessary monitoring infrastructure, especially for benzene (C 6H 6), which is a known human carcinogen. The use of environmental statistics combined with air quality modelling can be of vital importance in order to assess air quality levels of traffic-related pollutants in an urban area in the case where there are no available measurements. This paper aims at developing and presenting a reliable approach, in order to forecast C 6H 6 levels in urban environments, demonstrated for Thessaloniki, Greece. Multiple stepwise regression analysis is used and a strong statistical relationship is detected between C 6H 6 and CO. The adopted regression model is validated in order to depict its applicability and representativeness. The presented results demonstrate that the adopted approach is capable of capturing C 6H 6 concentration trends and should be considered as complementary to air quality monitoring.

  17. Spatially-varying surface roughness and ground-level air quality in an operational dispersion model.

    PubMed

    Barnes, M J; Brade, T K; MacKenzie, A R; Whyatt, J D; Carruthers, D J; Stocker, J; Cai, X; Hewitt, C N

    2014-02-01

    Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness.

  18. Air pollution critical levels in central México protected natural areas

    NASA Astrophysics Data System (ADS)

    Ruiz Suarez, L.; Andraca Ayala, G.; Mar Morales, B.; Garcia-reynoso, J.; Torres-JArdon, R.

    2013-05-01

    All the Natural Protected Areas (NPA) within the Central Mexico City Belt comprising five metropolitan areas including MCMA are under strong impact from air pollution. Ozone, nitrogen oxides and sulfur dioxide exceed critical levels for several types of vegetation. In this work we show the critical level maps for ozone, nitrogen oxides and sulfur dioxide for Sierra of Chichinautzin, the mountain that acts as the physical barrier to air pollution dispersion south of Mexico City Metropolitan Area, what makes of it a receptor area to MCMA pollution. Maps were made combining model outputs from WRF-Chem and passive samplers. We also describe a proposal to extend the observation network to all natural protected areas within the Central Mexico City Belt.

  19. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  20. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 2 2012-01-01 2012-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  1. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  2. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  3. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  4. Impact of natural gas extraction on Pah levels in ambient air

    PubMed Central

    Paulik, L. Blair; Donald, Carey E.; Smith, Brian W.; Tidwell, Lane G.; Hobbie, Kevin A.; Kincl, Laurel; Haynes, Erin N.; Anderson, Kim A.

    2015-01-01

    Natural gas extraction, often referred to as “fracking,” has increased rapidly in the U.S. in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. PAH levels were highest when samplers were closest to active wells. Additionally, PAH levels closest to natural gas activity were an order of magnitude higher than levels previously reported in rural areas. Sourcing ratios indicate that PAHs were predominantly petrogenic, suggesting that elevated PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. Closest to active wells, the risk estimated for maximum residential exposure was 2.9 in 10,000, which is above the U.S. EPA's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest. This work suggests that natural gas extraction may be contributing significantly to PAHs in air, at levels that are relevant to human health. PMID:25810398

  5. Impact of natural gas extraction on PAH levels in ambient air.

    PubMed

    Paulik, L Blair; Donald, Carey E; Smith, Brian W; Tidwell, Lane G; Hobbie, Kevin A; Kincl, Laurel; Haynes, Erin N; Anderson, Kim A

    2015-04-21

    Natural gas extraction, often referred to as "fracking," has increased rapidly in the U.S. in recent years. To address potential health impacts, passive air samplers were deployed in a rural community heavily affected by the natural gas boom. Samplers were analyzed for 62 polycyclic aromatic hydrocarbons (PAHs). Results were grouped based on distance from each sampler to the nearest active well. PAH levels were highest when samplers were closest to active wells. Additionally, PAH levels closest to natural gas activity were an order of magnitude higher than levels previously reported in rural areas. Sourcing ratios indicate that PAHs were predominantly petrogenic, suggesting that elevated PAH levels were influenced by direct releases from the earth. Quantitative human health risk assessment estimated the excess lifetime cancer risks associated with exposure to the measured PAHs. Closest to active wells, the risk estimated for maximum residential exposure was 2.9 in 10 000, which is above the U.S. EPA's acceptable risk level. Overall, risk estimates decreased 30% when comparing results from samplers closest to active wells to those farthest. This work suggests that natural gas extraction may be contributing significantly to PAHs in air, at levels that are relevant to human health.

  6. Does shift in oxygen level in soil air affect the trace gases emissions?

    NASA Astrophysics Data System (ADS)

    malghani, S.; Gleixner, G.; Trumbore, S.

    2013-12-01

    Biogenic processes in soil such as, trace gasses emissions are influenced by presence or absence of oxygen as it is a dominant final acceptor of electrons for number of biochemical processes. However, it is unknown that trace gases emissions from soil are influenced by the level of oxygen or not. To understand the impact of oxygen level on CO2, CH4 and N2O emissions, five contrasting soils which differ in land use and other properties, were incubated at constant temperature and moisture in an automated chamber measurement system. Automated system continuously (30 mL/min) flushed the chambers holding soil samples with inlet air of known composition and the outlet air, sampling the headspace of the column, was connected to an automated multiport stream selection valve (Valco) that directed the air stream from different columns sequentially to instrumental part (LiCOR6262,PICARRO2101i and PICCARO2301). Other greenhouse gases and isotopes (δ13C & D) of CH4 were sampled weekly using 2L flasks. Oxygen levels in inlet air were switched weekly, started from 20% followed by 10, 5, 2.5, 1, 0%, and all levels were repeated in reverse fashion (from 1 to 20%).The results showed that soil respiration was higher in soils that were rich in soil organic matter with higher microbial biomass. Three out of five soils exhibited a gradual decrease in soil respiration while shifting higher to lower O2 levels but no such impact was recorded during gradual increase in O2 level. The lowest respiration rates in all soil types were recorded under anaerobic conditions. Forest soils were rich in soil organic carbon and respired more CO2 than grassland or cropland soils. All soils oxidized CH4, except one grassland soil which was acidic in nature (pH=4.1), in the presence of O2 at all levels. Amount of CH4 oxidized varied among soil types and was highest in forest soils. Under anaerobic condition CH4 oxidation was not observed in any soil, while two soils (cropland and one grassland) emitted

  7. Non-Radiological Air Quality Modeling for the High-Level Waste Salt Disposition

    SciTech Connect

    Hunter, C.H.

    1999-11-29

    Dispersion modeling of non-radiological airborne emissions associated with the construction and operation of three alternatives for high-level waste salt disposition at the Savannah River Site has been completed. The results will be used by Department of Energy-Savannah River in the preparation of the salt disposition supplemental environmental impact statement. Estimated maximum ground-level concentrations of applicable regulated air pollutants of the site boundary and at the distance to a hypothetical, co-located onsite worker are summarized in tables. In all cases, model estimated ambient concentrations are less than regulatory standards.

  8. Relationships between estimated flame retardant emissions and levels in indoor air and house dust.

    PubMed

    Liagkouridis, I; Cequier, E; Lazarov, B; Palm Cousins, A; Thomsen, C; Stranger, M; Cousins, I T

    2016-09-10

    A significant number of consumer goods and building materials can act as emission sources of flame retardants (FRs) in the indoor environment. We investigate the relationship between the emission source strength and the levels of 19 brominated flame retardants (BFRs) and seven organophosphate flame retardants (OPFRs) in air and dust collected in 38 indoor microenvironments in Norway. We use modeling methods to back-calculate emission rates from indoor air and dust measurements and identify possible indications of an emission-to-dust pathway. Experimentally based emission estimates provide a satisfactory indication of the relative emission strength of indoor sources. Modeling results indicate an up to two orders of magnitude enhanced emission strength for OPFRs (median emission rates of 0.083 and 0.41 μg h(-1) for air-based and dust-based estimates) compared to BFRs (0.52 and 0.37 ng h(-1) median emission rates). A consistent emission-to-dust signal, defined as higher dust-based than air-based emission estimates, was identified for four of the seven OPFRs, but only for one of the 19 BFRs. It is concluded, however, that uncertainty in model input parameters could potentially lead to the false identification of an emission-to-dust signal.

  9. Quantile-based Bayesian maximum entropy approach for spatiotemporal modeling of ambient air quality levels.

    PubMed

    Yu, Hwa-Lung; Wang, Chih-Hsin

    2013-02-05

    Understanding the daily changes in ambient air quality concentrations is important to the assessing human exposure and environmental health. However, the fine temporal scales (e.g., hourly) involved in this assessment often lead to high variability in air quality concentrations. This is because of the complex short-term physical and chemical mechanisms among the pollutants. Consequently, high heterogeneity is usually present in not only the averaged pollution levels, but also the intraday variance levels of the daily observations of ambient concentration across space and time. This characteristic decreases the estimation performance of common techniques. This study proposes a novel quantile-based Bayesian maximum entropy (QBME) method to account for the nonstationary and nonhomogeneous characteristics of ambient air pollution dynamics. The QBME method characterizes the spatiotemporal dependence among the ambient air quality levels based on their location-specific quantiles and accounts for spatiotemporal variations using a local weighted smoothing technique. The epistemic framework of the QBME method can allow researchers to further consider the uncertainty of space-time observations. This study presents the spatiotemporal modeling of daily CO and PM10 concentrations across Taiwan from 1998 to 2009 using the QBME method. Results show that the QBME method can effectively improve estimation accuracy in terms of lower mean absolute errors and standard deviations over space and time, especially for pollutants with strong nonhomogeneous variances across space. In addition, the epistemic framework can allow researchers to assimilate the site-specific secondary information where the observations are absent because of the common preferential sampling issues of environmental data. The proposed QBME method provides a practical and powerful framework for the spatiotemporal modeling of ambient pollutants.

  10. Groundwater level and nitrate concentration trends on Mountain Home Air Force Base, southwestern Idaho

    USGS Publications Warehouse

    Williams, Marshall L.

    2014-01-01

    Mountain Home Air Force Base in southwestern Idaho draws most of its drinking water from the regional aquifer. The base is located within the State of Idaho's Mountain Home Groundwater Management Area and is adjacent to the State's Cinder Cone Butte Critical Groundwater Area. Both areas were established by the Idaho Department of Water Resources in the early 1980s because of declining water levels in the regional aquifer. The base also is listed by the Idaho Department of Environmental Quality as a nitrate priority area. The U.S. Geological Survey, in cooperation with the U.S. Air Force, began monitoring wells on the base in 1985, and currently monitors 25 wells for water levels and 17 wells for water quality, primarily nutrients. This report provides a summary of water-level and nitrate concentration data collected primarily between 2001 and 2013 and examines trends in those data. A Regional Kendall Test was run to combine results from all wells to determine an overall regional trend in water level. Groundwater levels declined at an average rate of about 1.08 feet per year. Nitrate concentration trends show that 3 wells (18 percent) are increasing in nitrate concentration trend, 3 wells (18 percent) show a decreasing nitrate concentration trend, and 11 wells (64 percent) show no nitrate concentration trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).

  11. Air radioactivity levels following the Fukushima reactor accident measured at the Laboratoire Souterrain de Modane, France.

    PubMed

    Loaiza, P; Brudanin, V; Piquemal, F; Reyss, J-L; Stekl, I; Warot, G; Zampaolo, M

    2012-12-01

    The radioactivity levels in the air of the radionuclides released by the Fukushima accident were measured at the Laboratoire Souterrain de Modane, in the South-East of France, during the period 25 March-18 April 2011. Air-filters from the ventilation system exposed for one or two days were measured using low-background gamma-ray spectrometry. In this paper we present the activity concentrations obtained for the radionuclides (131)I, (132)Te, (134)Cs, (137)Cs, (95)Nb, (95)Zr, (106)Ru, (140)Ba/La and (103)Ru. The activity concentration of (131)I was of the order of 100 μBq/m(3), more than 100 times higher than the activities of other fission products. The highest activities of (131)I were measured as a first peak on 30 March and a second peak on 3-4 April. The activity concentrations of (134)Cs and (137)Cs varied from 5 to 30 μBq/m(3). The highest activity concentration recorded for Cs corresponded to the same period as for (131)I, with a peak on 2-3 April. The results of the radioactivity concentration levels in grass and mushrooms exposed to the air in the Modane region were also measured. Activity concentrations of (131)I of about 100 mBq/m(2) were found in grass.

  12. Air levels and mutagenicity of PM-10 in an indoor ice arena

    SciTech Connect

    Georghiou, P.E.; Blagden, P.A. ); Snow, D.A.; Winsor, L. ); Williams, D.T. )

    1989-12-01

    The authors report here their results from a preliminary study to evaluate a methodology for surveying air quality by measuring concentrations of PM-10 and the corresponding concentrations of mutagenic activity. The PM-10 was collected, during several hockey games at an ice arena using an Indoor Air Sampling Impactor (IASI) developed by Marple et al. During the course of the study, smoking restrictions were imposed in the stadium and the impact of these restrictions on PM-10 levels was also evaluated. The mutagenic activities of solvent extracts of the PM-10 were determined using the microsuspension modification of the Samonella typhimurium/microsome test. Mutagenic activity has often been used as a rough index of exposure to potential carcinogens and mutagens and to help define their sources.

  13. [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.

  14. Exposure to air pollution in critical prenatal time windows and IgE levels in newborns.

    PubMed

    Herr, Caroline E W; Ghosh, Rakesh; Dostal, Miroslav; Skokanova, Venuse; Ashwood, Paul; Lipsett, Michael; Joad, Jesse P; Pinkerton, Kent E; Yap, Poh-Sin; Frost, Joshua D; Sram, Radim; Hertz-Picciotto, Irva

    2011-02-01

    The objective of this study was to analyze the mechanisms by which exposure to ambient air pollutants influences respiratory health may include altered prenatal immune development. To analyze associations between elevated cord serum Immunoglobulin E (IgE) levels and maternal air pollution exposure during each month of gestation. Total cord serum IgE was determined by the CAP system and mothers' total IgE levels by nephelometry for 459 births in the Czech Republic from May 1994 to mid-January 1997. Concentrations of polycyclic aromatic hydrocarbons (PAHs) and particulate matter <2.5 microns in diameter (PM(2.5) ) were measured in ambient air, and arithmetic means were calculated for each gestational month. Log binomial regression models were used to estimate prevalence ratios (PR) for elevated cord serum IgE (≥0.9 IU/ml) adjusting for district of residence, year of birth, and in further models, for maternal IgE (a surrogate for atopy) and gestational season. Heterogeneity by maternal atopy status was evaluated for associations of air pollution and of cigarette smoke. In adjusted models, PAH and PM(2.5) exposures in the second month of gestation were each associated with a lower prevalence of elevated cord serum IgE. For an average increase of 100 ng/m(3) of PAHs, the PR was 0.69 (95% confidence interval (CI): 0.50, 0.95); for 25 μg/m(3) increase in PM(2.5) , the PR was 0.77 (95% CI: 0.55, 1.07). Conversely, exposures later in gestation were associated with a higher prevalence of elevated cord IgE: in the fifth month, the PR for PAH exposure was 1.64 (95% CI: 1.29, 2.08), while for PM(2.5) in the sixth month, it was 1.66 (95% CI: 1.30, 2.13). In analyses stratified by maternal atopy, air pollutants were associated with altered cord serum IgE only among neonates with non-atopic mothers. Similarly, an association of cigarette smoke with elevated cord serum IgE was found only in non-atopic mothers. PAHs and PM(2.5) , constituents of both ambient air pollution and

  15. Passive inhalation of marijuana smoke: urinalysis and room air levels of delta-9-tetrahydrocannabinol

    SciTech Connect

    Cone, E.J.; Johnson, R.E.; Darwin, W.D.; Yousefnejad, D.; Mell, L.D.; Paul, B.D.; Mitchell, J.

    1987-05-01

    In two separate studies, 5 drug-free male volunteers with a history of marijuana use were passively exposed to the sidestream smoke of 4 and 16 marijuana cigarettes (2.8% delta-9-tetrahydrocannabinol (THC)) for 1 h each day for 6 consecutive days. A third study was similarly performed with 2 marijuana-naive subjects passively exposed to the smoke of 16 marijuana cigarettes. Passive smoke exposure was conducted in a small, unventilated room. Room air levels of THC and CO were monitored frequently. All urine specimens were collected and analyzed by EMIT d.a.u. assay, Abuscreen radioimmunoassay and GC/MS. The studies show that significant amounts of THC were absorbed by all subjects at the higher level of passive smoke exposure (eg., smoke from 16 marijuana cigarettes), resulting in urinary excretion of significant amounts of cannabinoid metabolites. However, it seems improbable that subjects would unknowingly tolerate the noxious smoke conditions produced by this exposure. At the lower level of passive marijuana-smoke exposure, specimens tested positive only infrequently or were negative. Room air levels of THC during passive smoke exposure appeared to be the most critical factor in determining whether a subject produced cannabinoid-positive urine specimens.

  16. Study on particulate matter air pollution in Beijing with MODIS aerosol level 2 products

    NASA Astrophysics Data System (ADS)

    Mao, Jietai; Li, Chengcai; Lau, Alexis K.

    2004-09-01

    In the run-up to the 2008 Olympic Games in Beijing, Chinese government officials at both the central and municipal levels are keenly aware that they must transform Beijing into a world-class city. According to the Beijing Municipal Environmental Protection Bureau (BJEPB) to improve its air quality some actions are adopting, including taking steps to increase the forested area surrounding the city preventing dust storms, reducing the automotive vehicles, moving polluting factories now inside the fourth ring road ringing the inner city to locations outside of the fourth ring road, and switching the fuel of public buses and taxis from diesel to natural gas, etc. Will they eliminate most serious environmental problems in Beijing? MODIS aerosol products are helping us to answer this kind of questions. A long-term validation has been finished by sun-photometer observations, and the results proved the relative error of MODIS level 2 products was slightly larger than the estimation of Chu et al. (2002) from the results in most AERONET sites. However, the comparison between the products and moisture-corrected air pollution index (API) data, which were daily released to public by EPB, showed a high correlation coefficient. An air pollution episode in 2003 was investigated by the usage of satellite products. Our conclusion for the air pollution control strategy in Beijing is that only reducing the pollution sources from inner city can't fully solve the pollution problems in Beijing and the regional transports from the nearby southern provinces are contributing a lot to the pollution situation in Beijing.

  17. Effect of Different Levels of Pressure Relieving Air-Mattress Firmness on Cough Strength.

    PubMed

    Kamikawa, Norimichi; Taito, Shunsuke; Takahashi, Makoto; Sekikawa, Kiyokazu; Hamada, Hironobu

    2016-01-01

    Cough is an important host-defense mechanism. The elderly and patients who are severely ill cannot cough effectively when lying in the supine position. Furthermore, pressure relieving air-mattresses are recommended for preventing the development of pressure ulcers. In this study, we clarified whether or not the cough peak flow (CPF), an index of cough strength, is affected by different firmness levels of a pressure relieving air-mattress in healthy volunteers in the supine position. Fifty-two healthy young men participated. All the measurements were carried out on each participant in the supine position on a pressure relieving air-mattress. The participants were assessed at two firmness levels, a "hard" and "soft" mode. The CPF, forced vital capacity (FVC), maximal expiratory pressure (PEmax), and maximal inspiratory pressure (PImax) were determined for each mode. The sinking distance of the body into the mattress was measured without any activity and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax, and PImax were determined for each mode. The sinking distance of the body into the mattress was measured and the difference between the sinking distances of the two firmness levels was determined. The CPF, FVC, PEmax and PImax values of the participants coughing on the mattress were significantly lower when the mattress was in "soft" than in "hard" mode. The differences between the sinking distances of the mattress in "soft" and "hard" modes were larger for the anterior superior iliac spine. A harder mattress may lead to increased CPF in healthy young men lying in the supine position, and increased CPF may be important for host defense.

  18. Correlations between health status and OralChroma™-determined volatile sulfide levels in mouth air of the elderly.

    PubMed

    Awano, Shuji; Takata, Yutaka; Soh, Inho; Yoshida, Akihiro; Hamasaki, Tomoko; Sonoki, Kazuo; Ohsumi, Tomoko; Nishihara, Tatsuji; Ansai, Toshihiro

    2011-12-01

    Dimethyl sulfide (DMS), a volatile sulfur compound (VSC) found in mouth air, is thought to be associated with systemic diseases; this in contrast to the two other VSCs found in mouth air: hydrogen sulfide and methyl mercaptan (MM). This study aimed to validate the relationship between DMS in mouth air and oral and systemic factors. The subjects were 393 elderly Japanese volunteers participating in an oral and systemic health survey. They were surveyed for the concentration of VSC components in their mouth air and for their oral and systemic health status. Using logistic regression models, the prevalence of DMS in mouth air above the organoleptic threshold level (OTL) was found to be significantly associated with high-density lipoprotein (HDL) cholesterol level, medical history of colon polyps and asthma, being female, and the presence of MM in mouth air above the OTL. Our data suggest that systemic factors, such as a high serum HDL cholesterol level and a medical history of asthma and colon polyps, might be more prominent in subjects with elevated DMS. The differences, although statistically significant, are quite small. They also indicate that an oral factor, such as a high MM mouth-air level also influences the DMS mouth-air level in addition to systemic factors.

  19. 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

  20. A real time sorbent based air monitoring system for determining low level airborne exposure levels to Lewisite

    SciTech Connect

    Lattin, F.G.; Paul, D.G.; Jakubowski, E.M.

    1994-12-31

    The Real Time Analytical Platform (RTAP) is designed to provide mobile, real-time monitoring support to ensure protection of worker safety in areas where military unique compounds are used and stored, and at disposal sites. Quantitative analysis of low-level vapor concentrations in air is accomplished through sorbent-based collection with subsequent thermal desorption into a gas chromatograph (GC) equipped with a variety of detectors. The monitoring system is characterized by its sensitivity (ability to measure at low concentrations), selectivity (ability to filter out interferences), dynamic range and linearity, real time mode (versus methods requiring extensive sample preparation procedures), and ability to interface with complimentary GC detectors. This presentation describes an RTAP analytical method for analyzing lewisite, an arsenical compound, that consists of a GC screening technique with an Electron Capture Detector (ECD), and a confirmation technique using an Atomic Emission Detector (AED). Included in the presentation is a description of quality assurance objectives in the monitoring system, and an assessment of method accuracy, precision and detection levels.

  1. Genetic effects of an air discharge plasma on Staphylococcus aureus at the gene transcription level

    NASA Astrophysics Data System (ADS)

    Xu, Zimu; Wei, Jun; Shen, Jie; Liu, Yuan; Ma, Ronghua; Zhang, Zelong; Qian, Shulou; Ma, Jie; Lan, Yan; Zhang, Hao; Zhao, Ying; Xia, Weidong; Sun, Qiang; Cheng, Cheng; Chu, Paul K.

    2015-05-01

    The dynamics of gene expression regulation (at transcription level) in Staphylococcus aureus after different doses of atmospheric-pressure room-temperature air plasma treatments are investigated by monitoring the quantitative real-time polymerase chain reaction. The plasma treatment influences the transcription of genes which are associated with several important bio-molecular processes related to the environmental stress resistance of the bacteria, including oxidative stress response, biofilm formation, antibiotics resistance, and DNA damage protection/repair. The reactive species generated by the plasma discharge in the gas phase and/or induced in the liquid phase may account for these gene expression changes.

  2. Proposal for a Vehicle Level Test Procedure to Measure Air Conditioning Fuel Use

    SciTech Connect

    Rugh, J. P.

    2010-04-01

    The air-conditioning (A/C) compressor load significantly impacts the fuel economy of conventional vehicles and the fuel use/range of plug-in hybrid electric vehicles (PHEV). A National Renewable Energy Laboratory (NREL) vehicle performance analysis shows the operation of the air conditioner reduces the charge depletion range of a 40-mile range PHEV from 18% to 30% in a worst case hot environment. Designing for air conditioning electrical loads impacts PHEV and electric vehicle (EV) energy storage system size and cost. While automobile manufacturers have climate control procedures to assess A/C performance, and the U.S. EPA has the SCO3 drive cycle to measure indirect A/C emissions, there is no automotive industry consensus on a vehicle level A/C fuel use test procedure. With increasing attention on A/C fuel use due to increased regulatory activities and the development of PHEVs and EVs, a test procedure is needed to accurately assess the impact of climate control loads. A vehicle thermal soak period is recommended, with solar lamps that meet the SCO3 requirements or an alternative heating method such as portable electric heaters. After soaking, the vehicle is operated over repeated drive cycles or at a constant speed until steady-state cabin air temperature is attained. With this method, the cooldown and steady-state A/C fuel use are measured. This method can be run at either different ambient temperatures to provide data for the GREEN-MAC-LCCP model temperature bins or at a single representative ambient temperature. Vehicles with automatic climate systems are allowed to control as designed, while vehicles with manual climate systems are adjusted to approximate expected climate control settings. An A/C off test is also run for all drive profiles. This procedure measures approximate real-world A/C fuel use and assess the impact of thermal load reduction strategies.

  3. Using Mobile Monitoring to Assess Spatial Variability in Urban Air Pollution Levels: Opportunities and Challenges (Invited)

    NASA Astrophysics Data System (ADS)

    Larson, T.

    2010-12-01

    Measuring air pollution concentrations from a moving platform is not a new idea. Historically, however, most information on the spatial variability of air pollutants have been derived from fixed site networks operating simultaneously over space. While this approach has obvious advantages from a regulatory perspective, with the increasing need to understand ever finer scales of spatial variability in urban pollution levels, the use of mobile monitoring to supplement fixed site networks has received increasing attention. Here we present examples of the use of this approach: 1) to assess existing fixed-site fine particle networks in Seattle, WA, including the establishment of new fixed-site monitoring locations; 2) to assess the effectiveness of a regulatory intervention, a wood stove burning ban, on the reduction of fine particle levels in the greater Puget Sound region; and 3) to assess spatial variability of both wood smoke and mobile source impacts in both Vancouver, B.C. and Tacoma, WA. Deducing spatial information from the inherently spatio-temporal measurements taken from a mobile platform is an area that deserves further attention. We discuss the use of “fuzzy” points to address the fine-scale spatio-temporal variability in the concentration of mobile source pollutants, specifically to deduce the broader distribution and sources of fine particle soot in the summer in Vancouver, B.C. We also discuss the use of principal component analysis to assess the spatial variability in multivariate, source-related features deduced from simultaneous measurements of light scattering, light absorption and particle-bound PAHs in Tacoma, WA. With increasing miniaturization and decreasing power requirements of air monitoring instruments, the number of simultaneous measurements that can easily be made from a mobile platform is rapidly increasing. Hopefully the methods used to design mobile monitoring experiments for differing purposes, and the methods used to interpret those

  4. 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.

  5. 24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... particleboard is produced or surface-finished, whichever is later, the panels must be dead-stacked or air-tight... with the Standard Test Method for Determining Formaldehyde Levels from Wood Products Under Defined...

  6. 24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... particleboard is produced or surface-finished, whichever is later, the panels must be dead-stacked or air-tight... with the Standard Test Method for Determining Formaldehyde Levels from Wood Products Under Defined...

  7. Assessment of air pollution tolerance levels of selected plants around cement industry, Coimbatore, India.

    PubMed

    Radhapriya, P; NavaneethaGopalakrishnan, A; Malini, P; Ramachandran, A

    2012-05-01

    Being the second largest manufacturing industry in India, cement industry is one of the major contributors of suspended particulate matter (SPM). Since plants are sensitive to air pollution, introducing suitable plant species as part of the greenbelt around cement industry was the objective of the present study. Suitable plant species were selected based on the Air pollution tolerance index (APTI) calculated by analyzing ascorbic acid (AA), pH, relative water content (RWC) and total chlorophyll (TChl) of the plants occuring in the locality. Plants were selected within a 6 km radius from the industry and were graded as per their tolerance levels by analyzing the biochemical parameters. From the statistical analysis at 0.05 level of significance a difference in the APTI values among the 27 plant species was observed, but they showed homogenous results when analysed zone wise using one-way analyses of variance. Analyses of individual parameters showed variation in the different zones surrounding the cement industry, whereas the APTI value (which is a combination of the parameter viz. AA, RWC, TChl, pH) showed more or less same gradation. Significant variation in individual parameters and APTI was seen with in the species. All the plants surrounding the cement industry are indicative of high pollution exposure comparable to the results obtain for control plants. Based on the APTI value, it was observed that about 37% of the plant species were tolerant. Among them Mangifera indica, Bougainvillea species, Psidum quajava showed high APTI values. 33% of the species were highly susceptible to the adverse effects of SPM, among which Thevetia neriifolia, Saraca indica, Phyllanthus emblica and Cercocarpus ledifolius showed low APTI values. 15% each of the species were at the intermediary and moderate tolerance levels.

  8. Low-level air pollution and upper respiratory infections in children.

    PubMed Central

    Jaakkola, J J; Paunio, M; Virtanen, M; Heinonen, O P

    1991-01-01

    Effects of low-level air pollution were studied in one polluted city and two reference cities in northern Finland by comparing the frequency of upper respiratory infections over a 12-month period in 1982 as reported by parents of children ages 14 through 18 months (n = 679) and 6 years (n = 759). A similar comparison was carried out between children living in the more polluted and less polluted areas of the polluted city. The annual mean and the greatest half-hour concentrations of sulfur dioxide (23 and 807 micrograms/m3), particulates (31 and 291 micrograms/m3), nitrogen oxides (15 and 160 micrograms/m3), and hydrogen sulfide (2 and 177 micrograms/m3) in the polluted city were mainly due to industrial sources. In the reference cities, air pollution was produced mainly by traffic and heating. Adjusted odds ratios (OR) for one or more upper respiratory infections of residents in the polluted city vs those in the reference cities were 2.0 (95% confidence interval [CI] = 1.3-3.2) in the younger age group and 1.6 (95% CI = 1.1-2.1) in the older age group. Within the polluted city, OR calculated for living in more vs less polluted areas were 2.0 (95% CI = 1.0-4.0) in the younger and 1.6 (95% CI = 1.0-2.7) in the older children. The present results suggests that, for children, air pollution can be hazardous in concentrations lower than those recorded in earlier studies from Britain and central Europe. The synergistic effect of sulfur dioxide, particulates, nitrogen oxides, hydrogen sulfide, and other pollutants may be a contributing factor. PMID:1854003

  9. Dependence with air density of the response of the PTW SourceCheck ionization chamber for low energy brachytherapy sources

    SciTech Connect

    Tornero-López, Ana M.; Guirado, Damián; Ruiz-Arrebola, Samuel; Perez-Calatayud, Jose; Simancas, Fernando; Lallena, Antonio M.; Gazdic-Santic, Maja

    2013-12-15

    Purpose: Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is corrected to standard atmospheric conditions using the usual temperature and pressure correction factor. Nevertheless, when assessing low energy sources, the ionization chambers may not fulfill that condition and a residual density dependence still remains after correction. In this work, the authors examined the behavior of the PTW 34051 SourceCheck ionization chamber when measuring the air kerma strength of {sup 125}I seeds.Methods: Four different SourceCheck chambers were analyzed. With each one of them, two series of measurements of the air kerma strength for {sup 125}I selectSeed{sup TM} brachytherapy sources were performed inside a pressure chamber and varying the pressure in a range from 747 to 1040 hPa (560 to 780 mm Hg). The temperature and relative humidity were kept basically constant. An analogous experiment was performed by taking measurements at different altitudes above sea level.Results: Contrary to other well-known ionization chambers, like the HDR1000 PLUS, in which the temperature-pressure correction factor overcorrects the measurements, in the SourceCheck ionization chamber they are undercorrected. At a typical atmospheric situation of 933 hPa (700 mm Hg) and 20 °C, this undercorrection turns out to be 1.5%. Corrected measurements show a residual linear dependence on the density and, as a consequence, an additional density dependent correction must be applied. The slope of this residual linear density dependence is different for each SourceCheck chamber investigated. The results obtained by taking measurements at different altitudes are compatible with those obtained with the pressure chamber.Conclusions: Variations of the altitude and

  10. Sea level oscillations in coastal waters of the Buenos Aires province, Argentina

    NASA Astrophysics Data System (ADS)

    Dragani, W. C.; Mazio, C. A.; Nuñez, M. N.

    2002-03-01

    Sea level oscillations, with periods ranging from a few minutes to almost 2 h, have been observed at various tide stations located on the coast of Buenos Aires. Simultaneous records of sea level elevation measured in Mar de Ajó, Pinamar and Mar del Plata during 1982 have been spectrally analyzed. Significant spectral energy has been detected between 0.85 and 4.69 cycles per hour (cph) and the most energetic peaks have frequencies between 1.17 and 1.49 cph. Spectra, coherence, and phase difference have been analyzed for the most energetic event of the year. During that event, the most intensive spectral peak is at 1.17 cph for Mar de Ajó and Pinamar, and at 1.49 cph for Mar del Plata. Simultaneous total energy peaks at Mar de Ajó, Pinamar and Mar del Plata, and the coherence function estimated between Mar de Ajó and Pinamar suggests that sea level oscillations could be a regional phenomenon. The analyzed data suggest that sea level oscillations could be forced by atmospheric gravity waves associated with frontal passages.

  11. Indoor air pollution levels in public buildings in Thailand and exposure assessment.

    PubMed

    Klinmalee, Aungsiri; Srimongkol, Kasama; Kim Oanh, Nguyen Thi

    2009-09-01

    Levels of pollutants including PM2.5 and PM2.5 composition (black carbon and water soluble ions), SO(2), NO(2), CO, CO(2), and BTEX (benzene, toluene, ethylbenzene, xylene) were monitored for indoor and outdoor air at a university campus and a shopping center, both located in the Northern suburb of Bangkok. Sampling was done during December 2005-February 2006 on both weekdays and weekends. At the university, indoor monitoring was done in two different air conditioned classrooms which shows the I/O ratios for all pollutants to be below 0.5-0.8 during the weekends. However, on weekdays the ratios for CO(2) and most detected BTEX were above 1.0. The concept of classroom occupancy was defined using a function of the student number in a lecture hour and the number of lecture hours per day. Classroom 2, which had a higher occupancy than classroom 1, was characterized by higher concentrations of most pollutants. PM2.5 was an exception and was higher in classroom 1 (37 microg/m(3), weekdays) as compared to classroom 2 (26 microg/m(3), weekdays) which was likely linked to the dust resuspension from the carpeted floor in the former. Monitoring was also done in the shopping mall at three different sites. Indoor pollutants levels and the I/O ratios at the shopping mall were higher than at the university. Levels of all pollutants measured at the car park, except for toluene and CO(2), were the highest. I/O ratios of the pollutants at the mall were above 1.0, which indicates the relatively higher influence of the indoor sources. However, the black carbon content in PM2.5 outdoor is higher than indoor, which suggest the important contribution from outdoor combustion sources such as the traffic. Major sources of outdoor air pollution in the areas were briefly discussed. Exposure modeling was applied using the time activity and measured pollutant concentrations to assess the exposure of different groups of people in the study areas. High exposure to PM2.5, especially for the people

  12. Theater-Level Stochastic Air-to-Air Engagement Modeling via Event Occurrence Networks Using Piecewise Polynomial Approximation

    DTIC Science & Technology

    2001-09-01

    light weight low recoil machine gun developed by Samuel Neal McClean with later improvement by Colonel USA Issac In reality air combat is far from...Forecast International Radar Forecast Forecast International Newton Conn Fowler Bruce W De Physica Belli An Introduction to

  13. A Well-Mixed Computational Model for Estimating Room Air Levels of Selected Constituents from E-Vapor Product Use

    PubMed Central

    Rostami, Ali A.; Pithawalla, Yezdi B.; Liu, Jianmin; Oldham, Michael J.; Wagner, Karl A.; Frost-Pineda, Kimberly; Sarkar, Mohamadi A.

    2016-01-01

    Concerns have been raised in the literature for the potential of secondhand exposure from e-vapor product (EVP) use. It would be difficult to experimentally determine the impact of various factors on secondhand exposure including, but not limited to, room characteristics (indoor space size, ventilation rate), device specifications (aerosol mass delivery, e-liquid composition), and use behavior (number of users and usage frequency). Therefore, a well-mixed computational model was developed to estimate the indoor levels of constituents from EVPs under a variety of conditions. The model is based on physical and thermodynamic interactions between aerosol, vapor, and air, similar to indoor air models referred to by the Environmental Protection Agency. The model results agree well with measured indoor air levels of nicotine from two sources: smoking machine-generated aerosol and aerosol exhaled from EVP use. Sensitivity analysis indicated that increasing air exchange rate reduces room air level of constituents, as more material is carried away. The effect of the amount of aerosol released into the space due to variability in exhalation was also evaluated. The model can estimate the room air level of constituents as a function of time, which may be used to assess the level of non-user exposure over time. PMID:27537903

  14. Developing Community-Level Policy and Practice to Reduce Traffic-Related Air Pollution Exposure

    PubMed Central

    Brugge, Doug; Patton, Allison P.; Bob, Alex; Reisner, Ellin; Lowe, Lydia; Bright, Oliver-John M.; Durant, John L.; Newman, Jim; Zamore, Wig

    2016-01-01

    The literature consistently shows associations of adverse cardiovascular and pulmonary outcomes with residential proximity to highways and major roadways. Air monitoring shows that traffic-related pollutants (TRAP) are elevated within 200–400 m of these roads. Community-level tactics for reducing exposure include the following: 1) HEPA filtration; 2) Appropriate air-intake locations; 3) Sound proofing, insulation and other features; 4) Land-use buffers; 5) Vegetation or wall barriers; 6) Street-side trees, hedges and vegetation; 7) Decking over highways; 8) Urban design including placement of buildings; 9) Garden and park locations; and 10) Active travel locations, including bicycling and walking paths. A multidisciplinary design charrette was held to test the feasibility of incorporating these tactics into near-highway housing and school developments that were in the planning stages. The resulting designs successfully utilized many of the protective tactics and also led to engagement with the designers and developers of the sites. There is a need to increase awareness of TRAP in terms of building design and urban planning. PMID:27413416

  15. Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana.

    PubMed

    Adu-Kumi, Sam; Kareš, Radovan; Literák, Jaromír; Borůvková, Jana; Yeboah, Philip O; Carboo, Derick; Akoto, Osei; Darko, Godfred; Osae, Shiloh; Klánová, Jana

    2012-07-01

    Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p'- and p,p'-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m(-3) (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p'-DDT/p,p'-DDE ratio suggested recent inputs of fresh technical DDT.

  16. Developing Community-Level Policy and Practice to Reduce Traffic-Related Air Pollution Exposure.

    PubMed

    Brugge, Doug; Patton, Allison P; Bob, Alex; Reisner, Ellin; Lowe, Lydia; Bright, Oliver-John M; Durant, John L; Newman, Jim; Zamore, Wig

    2015-06-01

    The literature consistently shows associations of adverse cardiovascular and pulmonary outcomes with residential proximity to highways and major roadways. Air monitoring shows that traffic-related pollutants (TRAP) are elevated within 200-400 m of these roads. Community-level tactics for reducing exposure include the following: 1) HEPA filtration; 2) Appropriate air-intake locations; 3) Sound proofing, insulation and other features; 4) Land-use buffers; 5) Vegetation or wall barriers; 6) Street-side trees, hedges and vegetation; 7) Decking over highways; 8) Urban design including placement of buildings; 9) Garden and park locations; and 10) Active travel locations, including bicycling and walking paths. A multidisciplinary design charrette was held to test the feasibility of incorporating these tactics into near-highway housing and school developments that were in the planning stages. The resulting designs successfully utilized many of the protective tactics and also led to engagement with the designers and developers of the sites. There is a need to increase awareness of TRAP in terms of building design and urban planning.

  17. Association between State Assistance on the Topic of Indoor Air Quality and School District-Level Policies That Promote Indoor Air Quality in Schools

    ERIC Educational Resources Information Center

    Everett Jones, Sherry; Doroski, Brenda; Glick, Sherry

    2015-01-01

    Nationally representative data from the 2012 School Health Policies and Practices Study examined whether state assistance on indoor air quality (IAQ) was associated with district-level policies and practices related to IAQ and integrated pest management (IPM). Districts in states that provided assistance on IAQ were more likely than districts not…

  18. Low levels of air pollution induce changes of lung function in a panel of schoolchildren.

    PubMed

    Moshammer, H; Hutter, H-P; Hauck, H; Neuberger, M

    2006-06-01

    In search of sensitive screening parameters for assessing acute effects of ambient air pollutants in young schoolchildren, the impact of 8-h average air pollution before lung function testing was investigated by oscillatory measurements of resistance and spirometry with flow-volume loops. At a central elementary school in Linz, the capital of Upper Austria, 163 children aged 7-10 yrs underwent repeated examinations at the same time of day during 1 school year, yielding a total of 11-12 lung function tests per child. Associations to mass concentrations of particulate matter and nitrogen dioxide (NO(2)) measured continuously at a nearby monitoring station were tested, applying the Generalised Estimating Equations model. Reductions per 10 microg.m(-3) (both for particles and for NO(2)) were in the magnitude of 1% for most lung function parameters. The most sensitive indicator for acute effects of combustion-related pollutants was a change in maximal expiratory flow in small airways. NO(2) at concentrations below current standards reduced (in the multipollutant model) the forced expiratory volume in one second by 1.01%, maximal instantaneous forced flow when 50% of the forced vital capacity remains to be exhaled (MEF(50%)) by 1.99% and MEF(25%) by 1.96%. Peripheral resistance increased by 1.03% per 10 microg.m(-3) of particulate matter with a 50% cut-off aerodynamic diameter of 2.5 mum (PM(2.5)). Resistance is less influenced by the child's cooperation and should be utilised more often in environmental epidemiology when screening for early signs of small airway dysfunction from urban air pollution, but cannot replace the measurement of MEF(50%) and MEF(25%). In the basic model, the reduction of these parameters per 10 microg.m(-3) was highest for NO(2), followed by PM(1), PM(2.5) and PM(10), while exposure to coarse dust (PM(10)-PM(2.5)) did not change end-expiratory flow significantly. All acute effects of urban air pollution found on the lung function of healthy

  19. Recoil proton, alpha particle, and heavy ion impacts on microdosimetry and RBE of fast neutrons: analysis of kerma spectra calculated by Monte Carlo simulation.

    PubMed

    Pignol, J P; Slabbert, J

    2001-02-01

    Fast neutrons (FN) have a higher radio-biological effectiveness (RBE) compared with photons, however the mechanism of this increase remains a controversial issue. RBE variations are seen among various FN facilities and at the same facility when different tissue depths or thicknesses of hardening filters are used. These variations lead to uncertainties in dose reporting as well as in the comparisons of clinical results. Besides radiobiology and microdosimetry, another powerful method for the characterization of FN beams is the calculation of total proton and heavy ion kerma spectra. FLUKA and MCNP Monte Carlo code were used to simulate these kerma spectra following a set of microdosimetry measurements performed at the National Accelerator Centre. The calculated spectra confirmed major classical statements: RBE increase is linked to both slow energy protons and alpha particles yielded by (n,alpha) reactions on carbon and oxygen nuclei. The slow energy protons are produced by neutrons having an energy between 10 keV and 10 MeV, while the alpha particles are produced by neutrons having an energy between 10 keV and 15 MeV. Looking at the heavy ion kerma from <15 MeV and the proton kerma from neutrons <10 MeV, it is possible to anticipate y* and RBE trends.

  20. SPONTANEOUS CATALYTIC WET AIR OXIDATION DURING PRE-TREATMENT OF HIGH-LEVEL RADIOACTIVE WASTE SLUDGE

    SciTech Connect

    Koopman, D.; Herman, C.; Pareizs, J.; Bannochie, C.; Best, D.; Bibler, N.; Fellinger, T.

    2009-10-01

    Savannah River Remediation, LLC (SRR) operates the Defense Waste Processing Facility for the U.S. Department of Energy at the Savannah River Site. This facility immobilizes high-level radioactive waste through vitrification following chemical pretreatment. Catalytic destruction of formate and oxalate ions to carbon dioxide has been observed during qualification testing of non-radioactive analog systems. Carbon dioxide production greatly exceeded hydrogen production, indicating the occurrence of a process other than the catalytic decomposition of formic acid. Statistical modeling was used to relate the new reaction chemistry to partial catalytic wet air oxidation of both formate and oxalate ions driven by the low concentrations of palladium, rhodium, and/or ruthenium in the waste. Variations in process conditions led to increases or decreases in the total oxidative destruction, as well as partially shifting the preferred species undergoing destruction from oxalate ion to formate ion.

  1. The influence of gravity levels on soot formation for the combustion of ethylene-air mixture

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Liu, D.; Li, S.; Li, Y.; Lou, C.

    2014-12-01

    The reduced mechanism coupled with 2D flame code using CHEMKIN II to investigate the effect of gravity on flame structure and soot formation in diffusion flames. The results show that the gravity has a rather significant effect on flame structure and soot formation. The visible flame height and peak soot volume fraction in general increases with the gravity from 1 g decreased to 0 g. The peak flame temperature decreases with decreasing gravity level. Comparing the calculated results from 1 g to 0 g, the flame shape becomes wider, the high temperature zone becomes shorter, the mixture velocity has a sharp decrease, the soot volume fraction has a sharp increase and CO and unprovided species distribution becomes wider along radial direction. At normal and half gravity, the flame is buoyancy controlled and the axial velocity is largely independent of the coflow air velocity. At microgravity (0 g), the flame is momentum controlled.

  2. Impacts of traffic-induced lead emissions on air, soil and blood lead levels in Beirut.

    PubMed

    Hashisho, Z; El-Fadel, M

    2004-01-01

    Lead is a purely toxic heavy metal which induces a wide variety of adverse physiologic effects. Nevertheless, it has been mined and used for more than 8,000 years. Among the different contemporary sources of lead pollution, traffic-induced emissions from the combustion of leaded gasoline is of particular concern, as it can constitute more than 90 percent of total lead emissions into the atmosphere in congested urban areas where no phase-out activities have been adopted. Gasoline lead content and traffic volume are strongly correlated with concentrations of lead in various environmental media. In the absence of policies to reduce the use of lead in gasoline or to favor the use of unleaded gasoline, leaded gasoline remains the predominant grade in many countries. This paper assesses the status of lead pollution from the combustion of leaded gasoline in Beirut based on field measurements of lead in air and roadside dust of urban and rural/suburban areas and recent data on soil and blood lead levels. Average atmospheric lead concentrations was about 1.86 microg m(-3) at urban locations and 0.147 microg m(-3) at suburban locations. The analysis of roadside dust revealed an average lead level of 353 microg g(-1) along urban streets and 125 microg g(-1) along rural/suburban roads. Blood lead levels were also relatively high in comparison to countries where leaded gasoline has been phased-out.

  3. Polycyclic aromatic hydrocarbons in air on small spatial and temporal scales - I. Levels and variabilities

    NASA Astrophysics Data System (ADS)

    Lammel, Gerhard; Klánová, Jana; Ilić, Predrag; Kohoutek, Jiří; Gasić, Bojan; Kovacić, Igor; Lakić, Nataša; Radić, Ranka

    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 the spatial and temporal variabilities and to explore the significance of averaging effects inherent to 24 h-sampling. Measurement uncertainty was quantified on basis of three independent side-by-side samplers, deployed at one of the sites. PAH abundances in the urban and rural environments differed largely. Levels at the urban sites exceeded the levels at the rural site by >100%. The discrepancy was largely dominated by emission of 3-4 ring PAHs in the city, while 5-6 ring PAHs were more evenly distributed between city sites and the hill site. During the night a higher fraction of the semivolatile PAHs might have been stored in the soil or sorbed to surfaces. PAH patterns were undistinguishable across the three sites. However, concentrations of more particle-associated substances differed significantly between the urban sites than between one of the urban sites and the rural site (3 σ uncertainty). Time-averaging (on a 24 h-basis) would have masked the significant inter-site differences of half of the substances which were found at different levels (on a 4 h-basis).

  4. Indoor air quality in Portuguese schools: levels and sources of pollutants.

    PubMed

    Madureira, J; Paciência, I; Pereira, C; Teixeira, J P; Fernandes, E de O

    2016-08-01

    Indoor air quality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM2.5 , PM10 , bacteria and fungi, carbon dioxide (CO2 ), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO2 and occupancy data. Concentrations of CO2 exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 μg/m(3) ) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations, and CO2 levels between schools exceeded the variability within schools. These findings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behavior, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools.

  5. An improved mathematical model for prediction of air quantity to minimise radiation levels in underground uranium mines.

    PubMed

    Panigrahi, Durga Charan; Sahu, Patitapaban; Mishra, Devi Prasad

    2015-02-01

    Ventilation is the primary means of controlling radon and its daughter concentrations in an underground uranium mine environment. Therefore, prediction of air quantity is the vital component for planning and designing of ventilation systems to minimise the radiation exposure of miners in underground uranium mines. This paper comprehensively describes the derivation and verification of an improved mathematical model for prediction of air quantity, based on the growth of radon daughters in terms of potential alpha energy concentration (PAEC), to reduce the radiation levels in uranium mines. The model also explains the prediction of air quantity depending upon the quality of intake air to the stopes. This model can be used to evaluate the contribution of different sources to radon concentration in mine atmosphere based on the measurements of radon emanation and exhalation. Moreover, a mathematical relationship has been established for quick prediction of air quantity to achieve the desired radon daughter concentration in the mines.

  6. Urban morphology and air quality in dense residential environments in Hong Kong. Part I: District-level analysis

    NASA Astrophysics Data System (ADS)

    Edussuriya, P.; Chan, A.; Ye, A.

    2011-09-01

    The link between urban morphology and air quality in various dense residential environments of Hong Kong are investigated through field measurements and statistical analysis. With regard to the myriads of parameters available in the literature, this study aims to identify the most important urban morphological parameters in the street-level and district levels that affect air quality dispersion in Hong Kong. The study postulates that there is an association between urban morphology and urban air quality and a statistical model is developed to explain the relationship amongst urban air quality, micro-meteorology and urban morphological dimension. The study considered 20 different urban residential areas in five major districts of Hong Kong and real-time street-level air pollutant and microclimatic data are collected. 21 morphological variables are identified and calculated based on the geometry of the urban fabric. This study is the first part of a series which focuses to identify whether district demarcation is correlated with air quality. According to the findings of statistical analysis, only 6 out of 21 morphological variables (complete aspect ratio, occlusivity, roughness height, zero-plane displacement height, total building volume/number of buildings, and standard deviation of height) report distinguishable variability at the district level. Their R2 (correlation coefficient) values vary from 0.2937 (plan area index) to 0.5457 (occlusivity) which is considered moderate to high. All these parameters describe the overall feature of the site rather than the specific geometric features of the street. It translates to the fact that in spite of the large in-district variations in morphological variables amongst the five districts, air pollution variations are insignificant for most of the variables and it means that air quality in Hong Kong are distinguishable not by district-level variable but rather in-site fabrics.

  7. Exploring EKC, trends of growth patterns and air pollutants concentration level in Malaysia: A Nemerow Index Approach

    NASA Astrophysics Data System (ADS)

    Bekhet, Hussain A.; >Tahira Yasmin,

    2013-06-01

    The present study examines an Environmental Kuznets Curve (EKC) hypothesis by analyzing annual data of air pollutants concentartion and per capita GDP as economic indicator over the (1996-2010) period in Malaysia. Nemerow Index Approach (I) used to generate a measures of air pollution. The results show that ambient air quality indicators supports the EKC hypothesis which stated that pollution levels increase as a country develops, but begin to decrease as rising incomes pass beyond a turning poin. Also, the I result is justifying that most pollutants are showing value less than 1.

  8. Distribution of air and serum PCDD/F levels of electric arc furnaces and secondary aluminum and copper smelters.

    PubMed

    Lee, Ching-Chang; Shih, Tung-Seng; Chen, Hsiu-Ling

    2009-12-30

    Metallurgical processes, such as smelting, can generate organic impurities such as organic chloride chemicals, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The objective of this study was to elucidate the serum PCDD/F levels of 134 workers and ambient air levels around electric arc furnaces (EAF), secondary copper smelters and secondary aluminum smelters (ALSs) in Taiwan. The highest serum PCDD/F levels were found in the ALSs workers (21.9 pg WHO-TEQ/g lipid), with lower levels in copper smelter workers (21.5 pg WHO-TEQ/g lipid), and the lowest in the EAF plant workers (18.8 pg WHO-TEQ/g lipid). This was still higher than the levels for residents living within 5 km of municipal waste incinerators (14.0 pg WHO-TEQ/g lipid). For ambient samples, the highest ambient air PCDD/F level was in the copper smelters (12.4 pg WHO-TEQ/Nm(3)), with lower levels in ALSs (7.2 pg WHO-TEQ/Nm(3)), and the lowest in the EAF industry (1.8 pg WHO-TEQ/Nm(3)). The congener profiles were consistent in serum and in air samples collected in the copper smelters, but not for ALSs and EAF. In secondary copper smelters, the air PCDD/Fs levels might be directly linked to the PCDD/Fs accumulated in the workers due to the exceedingly stable congener pattern of the PCDD/F emission.

  9. Peak Sound Pressure Levels and Associated Auditory Risk from an H[subscript 2]-Air "Egg-Splosion"

    ERIC Educational Resources Information Center

    Dolhun, John J.

    2016-01-01

    The noise level from exploding chemical demonstrations and the effect they could have on audiences, especially young children, needs attention. Auditory risk from H[subscript 2]- O2 balloon explosions have been studied, but no studies have been done on H[subscript 2]-air "eggsplosions." The peak sound pressure level (SPL) was measured…

  10. NIST gravimetrically prepared atmospheric level methane in dry air standards suite.

    PubMed

    Rhoderick, George C; Carney, Jennifer; Guenther, Franklin R

    2012-04-17

    The Gas Metrology Group at the National Institute of Standards and Technology was tasked, by a congressional climate change act, to support the atmospheric measurement community through standards development of key greenhouse gases. This paper discusses the development of a methane (CH(4)) primary standard gas mixture (PSM) suite to support CH(4) measurement needs over a large amount-of-substance fraction range 0.3-20,000 μmol mol(-1), but with emphasis at the atmospheric level 300-4000 nmol mol(-1). Thirty-six CH(4) in dry air PSMs were prepared in 5.9 L high-pressure aluminum cylinders with use of a time-tested gravimetric technique. Ultimately 14 of these 36 PSMs define a CH(4) standard suite covering the nominal ambient atmospheric range of 300-4000 nmol mol(-1). Starting materials of pure CH(4) and cylinders of dry air were exhaustively analyzed to determine the purity and air composition. Gas chromatography with flame-ionization detection (GC-FID) was used to determine a CH(4) response for each of the 14 PSMs where the reproducibility of average measurement ratios as a standard error was typically (0.04-0.26) %. An ISO 6134-compliant generalized least-squares regression (GenLine) program was used to analyze the consistency of the CH(4) suite. All 14 PSMs passed the u-test with residuals between the gravimetric and the GenLine solution values being between -0.74 and 1.31 nmol mol(-1); (0.00-0.16)% relative absolute. One of the 14 PSMs, FF4288 at 1836.16 ± 0.75 nmol mol(-1) (k = 1) amount-of-substance fraction, was sent to the Korea Research Institute of Standards and Science (KRISS), the Republic of Korea's National Metrology Institute, for comparison. The same PSM was subsequently sent to the National Oceanic and Atmospheric Administration (NOAA) for analysis to their standards. Results show agreement between KRISS-NIST of +0.13% relative (+2.3 nmol mol(-1)) and NOAA-NIST of -0.14% relative (-2.54 nmol mol(-1)).

  11. Estimating Causal Effects of Local Air Pollution on Daily Deaths: Effect of Low Levels

    PubMed Central

    Schwartz, Joel; Bind, Marie-Abele; Koutrakis, Petros

    2016-01-01

    further control efforts. Citation: Schwartz J, Bind MA, Koutrakis P. 2017. Estimating causal effects of local air pollution on daily deaths: effect of low levels. Environ Health Perspect 125:23–29; http://dx.doi.org/10.1289/EHP232 PMID:27203595

  12. On evaluating compliance with air pollution levels not to be exceeded more than once per year

    NASA Technical Reports Server (NTRS)

    Neustadter, H. E.; Sidik, S. M.

    1974-01-01

    The adequacy is considered of currently practiced monitoring and data reduction techniques for assessing compliance with 24-hour Air Quality Standards (AQS) not to be exceeded more than once per year. The present situation for suspended particulates is discussed. The following conclusions are reached: (1) For typical less than daily sampling (i.e., 60 to 120 24-hour samples per year) the deviation from independence of the data set should not be substantial. (2) The interchange of exponentiation and expectation operations in the EPA data reduction model, underestimates the second highest level by about 4 to 8 percent for typical sigma values. (3) Estimates of the second highest pollution level have associated with them a large statistical variability arising from the finite size of the sample. The 0.95 confidence interval ranges from + or - 40 percent for 120 samples per year to + or - 84 percent for 30 samples per year. (4) The design value suggested by EPA for abatement and/or control planning purposes typically gives a margin of safety of 60 to 120 percent.

  13. Physical Activity- and Alcohol-dependent Association Between Air Pollution Exposure and Elevated Liver Enzyme Levels: An Elderly Panel Study

    PubMed Central

    Kim, Kyoung-Nam; Lee, Hyemi; Kim, Jin Hee; Jung, Kweon; Lim, Youn-Hee; Hong, Yun-Chul

    2015-01-01

    Objectives: The deleterious effects of air pollution on various health outcomes have been demonstrated. However, few studies have examined the effects of air pollution on liver enzyme levels. Methods: Blood samples were drawn up to three times between 2008 and 2010 from 545 elderly individuals who regularly visited a community welfare center in Seoul, Korea. Data regarding ambient air pollutants (particulate matter ≤2.5 μm [PM2.5], nitrogen dioxide [NO2], ozone [O3], carbon monoxide, and sulfur dioxide) from monitoring stations were used to estimate air pollution exposure. The effects of the air pollutants on the concentrations of three liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], and γ-glutamyltranspeptidase [γ-GTP)]) were evaluated using generalized additive and linear mixed models. Results: Interquartile range increases in the concentrations of the pollutants showed significant associations of PM2.5 with AST (3.0% increase, p=0.0052), ALT (3.2% increase, p=0.0313), and γ-GTP (5.0% increase, p=0.0051) levels; NO2 with AST (3.5% increase, p=0.0060) and ALT (3.8% increase, p=0.0179) levels; and O3 with γ-GTP (5.3% increase, p=0.0324) levels. Significant modification of these effects by exercise and alcohol consumption was found (p for interaction <0.05). The effects of air pollutants were greater in non-exercisers and heavy drinkers. Conclusions: Short-term exposure to air pollutants such as PM2.5, NO2, and O3 is associated with increased liver enzyme levels in the elderly. These adverse effects can be reduced by exercising regularly and abstinence from alcohol. PMID:26081652

  14. Household-level disparities in cancer risks from vehicular air pollution in Miami

    NASA Astrophysics Data System (ADS)

    Collins, Timothy W.; Grineski, Sara E.; Chakraborty, Jayajit

    2015-09-01

    Environmental justice (EJ) research has relied on ecological analyses of socio-demographic data from areal units to determine if particular populations are disproportionately burdened by toxic risks. This article advances quantitative EJ research by (a) examining whether statistical associations found for geographic units translate to relationships at the household level; (b) testing alternative explanations for distributional injustices never before investigated; and (c) applying a novel statistical technique appropriate for geographically-clustered data. Our study makes these advances by using generalized estimating equations to examine distributive environmental inequities in the Miami (Florida) metropolitan area, based on primary household-level survey data and census block-level cancer risk estimates of hazardous air pollutant (HAP) exposure from on-road mobile emission sources. In addition to modeling determinants of on-road HAP cancer risk among all survey participants, two subgroup models are estimated to examine whether determinants of risk differ based on disadvantaged minority (Hispanic and non-Hispanic Black) versus non-Hispanic white racial/ethnic status. Results reveal multiple determinants of risk exposure disparities. In the model including all survey participants, renter-occupancy, Hispanic and non-Hispanic black race/ethnicity, the desire to live close to work/urban services or public transportation, and higher risk perception are associated with greater on-road HAP cancer risk; the desire to live in an amenity-rich environment is associated with less risk. Divergent subgroup model results shed light on the previously unexamined role of racial/ethnic status in shaping determinants of risk exposures. While lower socioeconomic status and higher risk perception predict significantly greater on-road HAP cancer risk among disadvantaged minorities, the desire to live near work/urban services or public transport predict significantly greater risk among

  15. Ground-level air pollution changes during a boreal wildland mega-fire.

    PubMed

    Bytnerowicz, Andrzej; Hsu, Yu-Mei; Percy, Kevin; Legge, Allan; Fenn, Mark E; Schilling, Susan; Frączek, Witold; Alexander, Diane

    2016-12-01

    The 2011 Richardson wildland mega-fire in the Athabasca Oil Sands Region (AOSR) in northern Alberta, Canada had large effects on air quality. At a receptor site in the center of the AOSR ambient PM2.5, O3, NO, NO2, SO2, NH3, HONO, HNO3, NH4(+) and NO3(-) were measured during the April-August 2011 period. Concentrations of NH3, HNO3, NO2, SO2 and O3 were also monitored across the AOSR with passive samplers, providing monthly summer and bi-monthly winter average values in 2010, 2011 and 2012. During the fire, hourly PM2.5 concentrations >450μgm(-3) were measured at the AMS 1 receptor site. The 24-h National Ambient Air Quality Standard (NAAQS) of 35μgm(-3) and the Canada Wide Standard (CWS) of 30μgm(-3) were exceeded on 13days in May and 7days in June. During the fire emission periods, sharp increases in NH3, HONO, HNO3, NH4(+), NO3(-) and total inorganic reactive N concentrations occurred, all closely correlated with the PM2.5 changes. There were large differences in the relative contribution of various N compounds to total inorganic N between the no-fire emission and fire emission periods. While in the absence of fires NO and NO2 dominated, their relative contribution during the fires was ~2 fold smaller, mainly due to increased NH3, NH4(+) and NO3(-). Concentrations of HONO and HNO3 also greatly increased during the fires, but their contribution to the total inorganic N pool was relatively small. Elevated NH3 and HNO3 concentrations affected large areas of northern Alberta during the Richardson Fire. While NH3 and HNO3 concentrations were not at levels considered toxic to plants, these gases contributed significantly to atmospheric N deposition. Generally, no significant changes in O3 and SO2 concentrations were detected and their ambient concentrations were below levels harmful to human health or sensitive vegetation.

  16. A novel multi-level interconnect scheme with air as low K inter-metal dielectric for ultradeep submicron application

    NASA Astrophysics Data System (ADS)

    Chen, Chung-Hui; Fang, Yean-Kuen; Lin, Chun-Sheng; Yang, Chih-Wei; Hsieh, Jang-Cheng

    2001-01-01

    In this letter, a novel multi-level interconnect scheme with air as the low K inter-metal dielectric for ultra large scale integrated circuit (ULSI) application in ultradeep submicron (UDSM) range is proposed. The detailed process integration with copper dual damascene processing is described. The feasibility of the scheme is examined by trimethylaluminum Raphael simulation for the effective dielectric constant and the cutoff frequency in a standard divide by three counter. The simulation results are also compared with these reported air gap formation technologies. The results show the developed multi-level interconnect system is suitable for UDSM application.

  17. Effects of bleed air extraction on thrust levels on the F404-GE-400 turbofan engine

    NASA Technical Reports Server (NTRS)

    Yuhas, Andrew J.; Ray, Ronald J.

    1992-01-01

    A ground test was performed to determine the effects of compressor bleed flow extraction on the performance of F404-GE-400 afterburning turbofan engines. The two engines were installed in the F/A-18 High Alpha Research Vehicle at the NASA Dryden Flight Research Facility. A specialized bleed ducting system was installed onto the aircraft to control and measure engine bleed airflow while the aircraft was tied down to a thrust measuring stand. The test was conducted on each engine and at various power settings. The bleed air extraction levels analyzed included flow rates above the manufacturer's maximum specification limit. The measured relationship between thrust and bleed flow extraction was shown to be essentially linear at all power settings with an increase in bleed flow causing a corresponding decrease in thrust. A comparison with the F404-GE-400 steady-state engine simulation showed the estimation to be within +/- 1 percent of measured thrust losses for large increases in bleed flow rate.

  18. Effects of bleed air extraction of thrust levels on the F404-GE-400 turbofan engine

    NASA Technical Reports Server (NTRS)

    Yuhas, Andrew J.; Ray, Ronald J.

    1992-01-01

    A ground test was performed to determine the effects of compressor bleed flow extraction on the performance of F404-GE-400 afterburning turbofan engines. The two engines were installed in the F/A-18 High Alpha Research Vehicle at the NASA Dryden Flight Research Facility. A specialized bleed ducting system was installed onto the aircraft to control and measure engine bleed airflow while the aircraft was tied down to a thrust measuring stand. The test was conducted on each engine and at various power settings. The bleed air extraction levels analyzed included flow rates above the manufacturer's maximum specification limit. The measured relationship between thrust and bleed flow extraction was shown to be essentially linear at all power settings with an increase in bleed flow causing a corresponding decrease in thrust. A comparison with the F404-GE-400 steady-state engine simulation showed the estimation to be within +/- 1 percent of measured thrust losses for large increases is bleed flow rate.

  19. Respiratory Health Symptoms among Students Exposed to Different Levels of Air Pollution in a Turkish City

    PubMed Central

    Gül, Hülya; Gaga, Eftade O.; Döğeroğlu, Tuncay; Özden, Özlem; Ayvaz, Özkan; Özel, Sevda; Güngör, Günay

    2011-01-01

    In this study, we aimed to investigate the frequency of respiratory health symptoms among high school students attending schools at industrial, urban and rural areas in a Turkish city. Three schools located in different zones of the city having different pollution characteristics were chosen based on the pollutant distribution maps using Geographical Information Systems (GIS) software. A cross-sectional survey was performed among 667 high school students in the schools. Outdoor and indoor nitrogen dioxide (NO2) and ozone (O3) concentrations were also measured by passive samplers in the same schools to investigate possible routes of exposure. Chronic pulmonary disease (OR = 1.49; 95%CI: 1.11–1.99; p = 0.008), tightness in the chest (OR = 1.57; 95%CI: 1.22–2.02; p = 0.001), morning cough (OR = 1.81 95%CI: 1.19–2.75; p = 0.006) were higher among students in the industrial zone where nitrogen dioxide and ozone levels were also highest. There were no indoor sources of nitrogen dioxide and ozone exists in the schools except for the dining hall. As a conclusion, this study has noticed that air pollution and respiratory health problems among high school students are high in industrial zones and the use of passive samplers combined with GIS is an effective tool that may be used by public health researchers to identify pollutant zones and persons at risk. PMID:21695031

  20. 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.

  1. Role of persistent low-level clouds in mitigating air quality impacts of wintertime cold pool conditions

    NASA Astrophysics Data System (ADS)

    VanReken, Timothy M.; Dhammapala, Ranil S.; Jobson, B. Thomas; Bottenus, Courtney L.; VanderSchelden, Graham S.; Kaspari, Susan D.; Gao, Zhongming; Zhu, Qiurui; Lamb, Brian K.; Liu, Heping; Johnston, Jeff

    2017-04-01

    The Yakima Air Wintertime Nitrate Study (YAWNS) was conducted in January 2013 to investigate the drivers of elevated levels of fine particulate matter (PM2.5) frequently present in the region during winter stagnation periods. An extended stagnation period occurred during the study. For the first four days of the event, skies were clear and the strong diel variation in air pollution patterns were consistent with the expected effects of strong low-level nighttime temperature inversions with moderate mixing during daylight hours. Later in the event a low-level cloud layer formed that persisted over the Yakima Valley for the next seven days while regional conditions remained stagnant. Coincident with the onset of cloud, the levels of all measured primary pollutants, including CO2, CO, NOx, particle number concentration, and black carbon, dropped dramatically and remained low with negligible diel variation for as long as the cloud layer was present. The observed patterns for these air pollutants are consistent with decreased stability and enhanced mixing associated with the cloud-topped boundary layer. Interestingly, levels of secondary pollutants, most notably particulate ammonium nitrate, did not exhibit the same decline. This difference may be due to shifts in the chemical production of secondary pollutants during cloudy conditions, or may merely reflect a further influence of mixing. The results imply that the best strategies for managing wintertime air quality during episodes of persistent cloud are likely different from those needed during clear-sky stagnation events.

  2. Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints.

    PubMed

    Som, Sanjoy M; Catling, David C; Harnmeijer, Jelte P; Polivka, Peter M; Buick, Roger

    2012-03-28

    According to the 'Faint Young Sun' paradox, during the late Archaean eon a Sun approximately 20% dimmer warmed the early Earth such that it had liquid water and a clement climate. Explanations for this phenomenon have invoked a denser atmosphere that provided warmth by nitrogen pressure broadening or enhanced greenhouse gas concentrations. Such solutions are allowed by geochemical studies and numerical investigations that place approximate concentration limits on Archaean atmospheric gases, including methane, carbon dioxide and oxygen. But no field data constraining ground-level air density and barometric pressure have been reported, leaving the plausibility of these various hypotheses in doubt. Here we show that raindrop imprints in tuffs of the Ventersdorp Supergroup, South Africa, constrain surface air density 2.7 billion years ago to less than twice modern levels. We interpret the raindrop fossils using experiments in which water droplets of known size fall at terminal velocity into fresh and weathered volcanic ash, thus defining a relationship between imprint size and raindrop impact momentum. Fragmentation following raindrop flattening limits raindrop size to a maximum value independent of air density, whereas raindrop terminal velocity varies as the inverse of the square root of air density. If the Archaean raindrops reached the modern maximum measured size, air density must have been less than 2.3 kg m(-3), compared to today's 1.2 kg m(-3), but because such drops rarely occur, air density was more probably below 1.3 kg m(-3). The upper estimate for air density renders the pressure broadening explanation possible, but it is improbable under the likely lower estimates. Our results also disallow the extreme CO(2) levels required for hot Archaean climates.

  3. Indoor Air Quality in Schools (IAQ): The Importance of Monitoring Carbon Dioxide Levels.

    ERIC Educational Resources Information Center

    Sundersingh, David; Bearg, David W.

    This article highlights indoor air quality and exposure to pollutants at school. Typical air pollutants within schools include environmental tobacco smoke, formaldehyde, volatile organic compounds, nitrogen oxides, carbon monoxide, carbon dioxide, allergens, pathogens, radon, pesticides, lead, and dust. Inadequate ventilation, inefficient…

  4. AIR LEVELS OF CARCINOGENIC POLYCYCLIC AROMATIC HYDROCARBONS FOLLOWING THE WORLD TRADE CENTER DISASTER

    EPA Science Inventory

    The catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, created an immense dust cloud followed by fires that emitted soot into the air of New York City (NYC) well into December. The subsequent cleanup used diesel equipment that further polluted the air un...

  5. ANTIOXIDANT SUPPLEMENTATION AND LUNG FUNCTIONS AMONG ASTHMATIC CHILDREN EXPOSED TO HIGH LEVELS OF AIR POLLUTANTS

    EPA Science Inventory

    Abstract

    Air pollutant exposure has been related to adverse respiratory effects, in particular, in asthmatics. This effect could be the consequence of the oxidative stress caused by air pollutants on the lung. Antioxidant vitamins are free- radical scavengers, and could ha...

  6. Levels of persistent organic pollutants in air in China and over the Yellow Sea

    NASA Astrophysics Data System (ADS)

    Lammel, Gerhard; Ghim, Young-Sung; Grados, Amélie; Gao, Huiwang; Hühnerfuss, Heinrich; Lohmann, Rainer

    The occurrence of persistent toxic substances (PTS) in China and possibly their regional transport in the Yellow and East China Seas region was studied. Organochlorines in atmospheric gas-phase and particulate matter were collected by high-volume sampling (filters and polyurethane foams) during 2 weeks in June 2003 (dry season) simultaneously at a Yellow Sea coastal site in an urban area, Qingdao, China, and a rural island site, Gosan, Jeju Island, Korea. Using GC methods, the samples were analysed for 9 persistent organic pollutants (POPs) regulated under the global POP convention, namely aldrin, chlordane ( cis- and trans-isomers CC and TC), DDT and metabolites ( o, p'-DDT, p, p'-DDD, and p, p'-DDE), dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex and PCB (congeners number 28, 52, 101, 153 and 180), and for hexachlorocyclohexane ( α-, β- and γ-isomers), a PTS and now considered for regulation under the convention, too. At the coastal site additionally o, p'-DDE and -DDD, β-endosulfan, isodrin, heptachlorepoxide and δ-HCH, and at the island site additionally p, p'-DDT and 12 additional PCB congeners were analysed. 9 samples were collected at the coastal and 15 (for PCBs 5) at the island site. Long-range advection pathways were determined based on analysed back-trajectory calculations. The mean concentrations of DDT and its metabolites, HCB, HCH, and PCB at the coast were in the 100-1000 pg m -3 range. Higher concentrations prevailed during nighttime. The levels were in general lower at the island site, but not for DDT. Local sources are likely. PCBs were even 2 orders of magnitude lower, suggesting that PCBs are not subject to regional transport but elevated concentrations in air are limited to the source areas. Organochlorine pesticide levels on the other hand were seemingly determined by regional transport over Mainland China rather than by emissions in the coastal area. The currently used pesticides mirex and chlordane were found at elevated

  7. Air pressure effects on sea level changes during the twentieth century

    NASA Astrophysics Data System (ADS)

    Piecuch, Christopher G.; Thompson, Philip R.; Donohue, Kathleen A.

    2016-10-01

    Interpretation of tide gauge data in terms sea level (η) and ocean dynamics requires estimates of air pressure (pa) to determine the ocean's isostatic response—the inverted barometer effect (ηib). Three gridded pa products (HadSLP2, NOAA-20CRv2, and ERA-20C) are used alongside meteorological station pa and tide gauge η records to evaluate the contribution of ηib to η changes over the twentieth century. Agreement between gridded products is better during more recent periods and over regions with good historical data coverage, whereas it is worse for earlier time periods or in ocean areas with poor observational data coverage. Comparison against station data reveals the presence of systematic errors in the gridded products, for example, such that uncertainties estimated through differencing the gridded products underestimate the true errors by roughly 40% on interannual and decadal time scales. Notwithstanding such correlated errors, gridded products are still useful for interpretation of tide gauge data. Removing gridded estimates of ηib from η records reduces spatial variance in centennial trends across tide gauges by 10-30%, formal errors in centennial trends from individual gauges by ˜5%, and the temporal variance in detrended records by 10-15% on average (depending on choice of gridded product). Results here advocate for making the ηib correction to tide gauge records in studies of ocean circulation and global η over long, multidecadal, and centennial time scales using an ensemble mean taken across several gridded ηib products.

  8. Influence of synoptic and local atmospheric patterns on PM10 air pollution levels: a model application to Naples (Italy)

    NASA Astrophysics Data System (ADS)

    Fortelli, Alberto; Scafetta, Nicola; Mazzarella, Adriano

    2016-10-01

    We investigate the relationship between synoptic/local meteorological patterns and PM10 air pollution levels in the metropolitan area of Naples, Italy. We found that severe air pollution crises occurred when the 850 and 500 hpa geopotential heights and their relative temperatures present maximum values above the city. The most relevant synoptic parameter was the 850 hPa geopotential height, which is located about 1500 m of altitude. We compared local meteorological conditions (specifically wind stress, rain amount and thermal inversion) against the urban air pollution levels from 2009 to 2013. We found several empirical criteria for forecasting high daily PM10 air pollution levels in Naples. Pollution crises occurred when (a) the wind stress was between 1 and 2 m/s, (b) the thermal inversion between two strategic locations was at least 3°C/200 m and (c) it did not significantly rain for at least 7 days. Beside these meteorological conditions, severe pollution crises occurred also during festivals when fireworks and bonfires are lighted, and during anomalous breeze conditions and severe fire accidents. Finally, we propose a basic model to predict PM10 concentration levels from local meteorological conditions that can be easily forecast a few days in advance. The synthetic PM10 record predicted by the model was found to correlate with the PM10 observations with a correlation coefficient close to 0.80 with a confidence level greater than 99%. The proposed model is expected to provide reliable information to city officials to carry out practical strategies to mitigate air pollution effects. Although the proposed model equation is calibrated on the topographical and meteorological conditions of Naples, it should be easily adaptable to alternative locations.

  9. 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)

  10. Energetic delayed hadrons in large air showers observed at 5200m above sea level

    NASA Technical Reports Server (NTRS)

    Kaneko, T.; Hagiwara, K.; Yoshii, H.; Martinic, N.; Siles, L.; Miranda, P.; Kakimoto, F.; Tsuchimoto, I.; Inoue, N.; Suga, K.

    1985-01-01

    Energetic delayed hadrons in air showers with electron sizes in the range 10 to the 6th power to 10 to the 9th power were studied by observing the delayed bursts produced in the shield of nine square meter scintillation detectors in the Chacaltaya air-shower array. The frequency of such delayed burst is presented as a function of electron size, core distance and sec theta.

  11. When the Balloon Goes Up: Barrage Balloons for Low-Level Air Defense.

    DTIC Science & Technology

    1988-04-01

    the British and the Argentines in the Falkland Islands War offer a fairly recent example of fast, ultra low-flying aircraft negating air defenses and...34 (11:45) Against ground targets the Argentine pilots used the same tactics, hugging the contours of the land to shield them against early warning...bottoms for the last two to three hours of daylight. . . .(25:88) The Argentine Air Force scored some noticeable victories during the war despite the long

  12. Air Force Working Capital Fund: Actions Needed to Manage Cash Balances to Required Levels

    DTIC Science & Technology

    2014-07-01

    on receiving daily cash balances. • Because airlift rates are set to compete with private sector rates , they do not cover the full cost. The...the maximum cash requirement for fiscal year 2009. Air Force headquarters officials informed us that when they set the rates to be charged to CSAG and... Rates Too High for Supply Items Monthly Cash Balances Fluctuated Because of the Cyclical Nature of Events Page 12 GAO-14-480 Air Force

  13. SU-E-I-53: Comparison of Kerma-Area-Product Between the Micro-Angiographic Fluoroscope (MAF) and a Flat Panel Detector (FPD) as Used in Neuro-Endovascular Procedures

    SciTech Connect

    Vijayan, S; Rana, V; Nagesh, S Setlur; Xiong, Z; Rudin, S; Bednarek, D

    2015-06-15

    Purpose: To determine the reduction of integral dose to the patient when using the micro-angiographic fluoroscope (MAF) compared to when using the standard flat-panel detector (FPD) for the techniques used during neurointerventional procedures. Methods: The MAF is a small field-of-view, high resolution x-ray detector which captures 1024 x 1024 pixels with an effective pixel size of 35μm and is capable of real-time imaging up to 30 frames per second. The MAF was used in neuro-interventions during those parts of the procedure when high resolution was needed and the FPD was used otherwise. The technique parameters were recorded when each detector was used and the kerma-area-product (KAP) per image frame was determined. KAP values were calculated for seven neuro interventions using premeasured calibration files of output as a function of kVp and beam filtration and included the attenuation of the patient table for the frontal projections to be more representative of integral patient dose. The air kerma at the patient entrance was multiplied by the beam area at that point to obtain the KAP values. The ranges of KAP values per frame were determined for the range of technique parameters used during the clinical procedures. To appreciate the benefit of the higher MAF resolution in the region of interventional activity, DA technique parameters were generally used with the MAF. Results: The lowest and highest values of KAP per frame for the MAF in DA mode were 4 and 50 times lower, respectively, compared to those of the FPD in pulsed fluoroscopy mode. Conclusion: The MAF was used in those parts of the clinical procedures when high resolution and image quality was essential. The integral patient dose as represented by the KAP value was substantially lower when using the MAF than when using the FPD due to the much smaller volume of tissue irradiated. This research was supported in part by Toshiba Medical Systems Corporation and NIH Grant R01EB002873.

  14. Artificial neural networks as a useful tool to predict the risk level of Betula pollen in the air

    NASA Astrophysics Data System (ADS)

    Castellano-Méndez, M.; Aira, M. J.; Iglesias, I.; Jato, V.; González-Manteiga, W.

    2005-05-01

    An increasing percentage of the European population suffers from allergies to pollen. The study of the evolution of air pollen concentration supplies prior knowledge of the levels of pollen in the air, which can be useful for the prevention and treatment of allergic symptoms, and the management of medical resources. The symptoms of Betula pollinosis can be associated with certain levels of pollen in the air. The aim of this study was to predict the risk of the concentration of pollen exceeding a given level, using previous pollen and meteorological information, by applying neural network techniques. Neural networks are a widespread statistical tool useful for the study of problems associated with complex or poorly understood phenomena. The binary response variable associated with each level requires a careful selection of the neural network and the error function associated with the learning algorithm used during the training phase. The performance of the neural network with the validation set showed that the risk of the pollen level exceeding a certain threshold can be successfully forecasted using artificial neural networks. This prediction tool may be implemented to create an automatic system that forecasts the risk of suffering allergic symptoms.

  15. Carbonyl levels in indoor and outdoor air in Mexico City and Xalapa, Mexico.

    PubMed

    Báez, Armando; Padilla, Hugo; García, Rocío; Torres, Ma del Carmen; Rosas, Irma; Belmont, Raúl

    2003-01-20

    Carbonyl compounds in air were measured at two houses, three museums, and two offices. All sites lacked air-conditioning systems. Although indoor and outdoor air was measured simultaneously at each site, the sites themselves were sampled in different dates. Mean concentrations were higher in indoor air. Outdoor means concentrations of acetone were the highest in all sites, ranging from 12 to 60 microg m(-3). In general, formaldehyde and acetaldehyde had similar mean concentrations, ranging from 4 to 32 and 6 to 28 microg m(-3), respectively. Formaldehyde and acetone mean indoor concentrations were the highest, ranging from 11 to 97 and 17 to 89 microg m(-3), respectively, followed by acetaldehyde with 5 to 47 microg m(-3). Formaldehyde and acetaldehyde had the highest mean concentration in the offices where there were smokers. Propionaldehyde and butyraldehyde concentrations did not show definite differences between indoor and outdoor air. In general, the highest outdoor and indoor hourly concentrations were observed from 10:00 to 15:00 h. Mean indoor/outdoor ratios of carbonyls exceeded 1. Formaldehyde and acetaldehyde risks were higher in smoking environments.

  16. Proinflammatory and anti-inflammatory cytokines in adolescents from Southeast Bulgarian cities with different levels of air pollution.

    PubMed

    Dobreva, Zlatka Georgieva; Kostadinova, Gergana Stoianova; Popov, Borislav Nikolov; Petkov, Georgi Stefanov; Stanilova, Spaska Angelova

    2015-12-01

    Epidemiological studies demonstrated that the exposure of different air pollutants including particulate matter (PM) has been related to adverse effect on immune system. Current study was designed to investigate cytokines in blood plasma of adolescent persons continuously exposed to different degrees of ambient air pollutions. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), IL-12p40, and IL-10 were chosen as cytokines of proinflammatory and anti-inflammatory immune response. The peripheral venous blood was taken from adolescents living in the cities of Stara Zagora region, Southeast Bulgaria, that is, in Stara Zagora, Kazanlak, and Chirpan. The quantity of cytokines in plasma samples was determined by enzyme-linked immunosorbent assay. Results demonstrated that youths living in Stara Zagora showed significantly smaller quantity of TNF-α, compared with adolescents from Kazanlak and Chirpan. Moreover, adolescents living in Stara Zagora showed significantly higher quantity of IL-10 than students from Kazanlak and Chirpan. Analysis of the data of air quality gives reason to assert that PM10 and PM2.5 have been the main atmospheric pollutants around the monitoring points. The complex air quality assessment based on these criteria determined that the highest air pollution was in the city of Stara Zagora, followed by Chirpan and the relatively unpolluted town was Kazanlak. We concluded that air pollutants, mostly PM2.5, can modulate cytokine production and can change the balance between proinflammatory TNF-α and anti-inflammatory IL-10 production. Increased levels of IL-10 combined with decreased level of TNF-α in adolescents living in Stara Zagora can serve as a biomarker for suppression of T helper 1 (Th1) cell-mediated immunity and exacerbation of Th2 humoral immune response and could be a prerequisite for the development of allergic and autoimmune diseases.

  17. A piloted simulation investigation of yaw dynamics requirements for turreted gun use in low-level helicopter air combat

    NASA Technical Reports Server (NTRS)

    Decker, William A.; Morris, Patrick M.; Williams, Jeffrey N.

    1988-01-01

    A piloted, fixed-base simulation study was conducted to investigate the handling qualities requirements for helicopter air-to-air combat using turreted guns in the near-terrain environment. The study used a version of the helicopter air combat system developed at NASA Ames Research Center for one-on-one air combat. The study focused on the potential trade-off between gun angular movement capability and required yaw axis response. Experimental variables included yaw axis response frequency and damping and the size of the gun-movement envelope. A helmet position and sighting system was used for pilot control of gun aim. Approximately 340 simulated air combat engagements were evaluated by pilots from the Army and industry. Results from the experiment indicate that a highly-damped, high frequency yaw response was desired for Level I handling qualities. Pilot preference for those characteristics became more pronounced as gun turret movement was restricted; however, a stable, slow-reacting platform could be used with a large turret envelope. Most pilots preferred to engage with the opponent near the own-ship centerline. Turret elevation restriction affected the engagement more than azimuth restrictions.

  18. Personal exposures, indoor-outdoor relationships, and breath levels of toxic air pollutants measured for 355 persons in New Jersey

    NASA Astrophysics Data System (ADS)

    Wallace, Lance A.; Pellizzari, Edo D.; Hartwell, Ty D.; Sparacino, Charles M.; Sheldon, Linda S.; Zelon, Harvey

    EPA's TEAM Study has measured exposures to 20 volatile organic compounds in personal air, outdoor air, drinking water and the breath of 355 persons in NJ, in the fall of 1981. The NJ residents were selected by a probability sampling scheme to represent 128,000 inhabitants of Elizabeth and Bayonne. Participants carried a personal monitor to collect two 12-h air samples and gave a breath sample at the end of the day. Two consecutive 12-h outdoor air samples were also collected on identical Tenax cartridges in the back yards of 90 of the participants. About 3000 samples were collected, of which 1000 were quality control samples. Eleven compounds were often present in air. Personal exposures were consistently higher than outdoor concentrations for these chemicals, and were sometimes ten times the outdoor concentrations. Indoor sources appeared responsible for much of the difference. Breath concentrations also usually exceed outdoor concentrations, and correlated more strongly with personal exposures than with outdoor concentrations. Some activities (smoking, driving, visiting dry cleaners or service stations) and occupations (chemical, paint and plastics plants) were associated with significantly elevated exposures and breath levels for certain toxic chemicals.

  19. Residential heating contribution to level of air pollutants (PAHs, major, trace, and rare earth elements): a moss bag case study.

    PubMed

    Vuković, Gordana; Aničić Urošević, Mira; Pergal, Miodrag; Janković, Milan; Goryainova, Zoya; Tomašević, Milica; Popović, Aleksandar

    2015-12-01

    In areas with moderate to continental climates, emissions from residential heating system lead to the winter air pollution peaks. The EU legislation requires only the monitoring of airborne concentrations of particulate matter, As, Cd, Hg, Ni, and B[a]P. Transition metals and rare earth elements (REEs) have also arisen questions about their detrimental health effects. In that sense, this study examined the level of extensive set of air pollutants: 16 polycyclic aromatic hydrocarbons (PAHs), and 41 major elements, trace elements, and REEs using Sphagnum girgensohnii moss bag technique. During the winter of 2013/2014, the moss bags were exposed across Belgrade (Serbia) to study the influence of residential heating system to the overall air quality. The study was set as an extension to our previous survey during the summer, i.e., non-heating season. Markedly higher concentrations of all PAHs, Sb, Cu, V, Ni, and Zn were observed in the exposed moss in comparison to the initial values. The patterns of the moss REE concentrations normalized to North American Shale Composite and Post-Archean Australian Shales were identical across the study area but enhanced by anthropogenic activities. The results clearly demonstrate the seasonal variations in the moss enrichment of the air pollutants. Moreover, the results point out a need for monitoring of air quality during the whole year, and also of various pollutants, not only those regulated by the EU Directive.

  20. Flying-qualities criteria for wings-level-turn maneuvering during an air-to-ground weapon delivery task

    NASA Technical Reports Server (NTRS)

    Sammonds, R. I.; Bunnell, J. W., Jr.

    1980-01-01

    A moving-base simulator experiment conducted at Ames Research Center demonstrated that a wings-level-turn control mode improved flying qualities for air-to-ground weapons delivery compared with those of a conventional aircraft. Evaluations of criteria for dynamic response for this system have shown that pilot ratings correlate well on the basis of equivalent time constant of the initial response. Ranges of this time constant, as well as digital-system transport delays and lateral-acceleration control authorities that encompassed Level I through Level III handling qualities, were determined.

  1. Burden of Outdoor Air Pollution in Kerala, India—A First Health Risk Assessment at State Level.

    PubMed

    Tobollik, Myriam; Razum, Oliver; Wintermeyer, Dirk; Plass, Dietrich

    2015-08-28

    Ambient air pollution causes a considerable disease burden, particularly in South Asia. The objective of the study is to test the feasibility of applying the environmental burden of disease method at state level in India and to quantify a first set of disease burden estimates due to ambient air pollution in Kerala. Particulate Matter (PM) was used as an indicator for ambient air pollution. The disease burden was quantified in Years of Life Lost (YLL) for the population (30 + years) living in urban areas of Kerala. Scenario analyses were performed to account for uncertainties in the input parameters. 6108 (confidence interval (95% CI): 4150-7791) of 81,636 total natural deaths can be attributed to PM, resulting in 96,359 (95% CI: 65,479-122,917) YLLs due to premature mortality (base case scenario, average for 2008-2011). Depending on the underlying assumptions the results vary between 69,582 and 377,195 YLLs. Around half of the total burden is related to cardiovascular deaths. Scenario analyses show that a decrease of 10% in PM concentrations would save 15,904 (95% CI: 11,090-19,806) life years. The results can be used to raise awareness about air quality standards at a local level and to support decision-making processes aiming at cleaner and healthier environments.

  2. Lacrimal Cytokines Assessment in Subjects Exposed to Different Levels of Ambient Air Pollution in a Large Metropolitan Area

    PubMed Central

    Matsuda, Monique; Bonatti, Rodolfo; Marquezini, Mônica V.; Garcia, Maria L. B.; Santos, Ubiratan P.; Braga, Alfésio L. F.; Alves, Milton R.

    2015-01-01

    Background Air pollution is one of the most environmental health concerns in the world and has serious impact on human health, particularly in the mucous membranes of the respiratory tract and eyes. However, ocular hazardous effects to air pollutants are scarcely found in the literature. Design Panel study to evaluate the effect of different levels of ambient air pollution on lacrimal film cytokine levels of outdoor workers from a large metropolitan area. Methods Thirty healthy male workers, among them nineteen professionals who work on streets (taxi drivers and traffic controllers, high pollutants exposure, Group 1) and eleven workers of a Forest Institute (Group 2, lower pollutants exposure compared to group 1) were evaluated twice, 15 days apart. Exposure to ambient PM2.5 (particulate matter equal or smaller than 2.5 μm) was 24 hour individually collected and the collection of tears was performed to measure interleukins (IL) 2, 4, 5 and 10 and interferon gamma (IFN-γ) levels. Data from both groups were compared using Student’s t test or Mann- Whitney test for cytokines. Individual PM2.5 levels were categorized in tertiles (lower, middle and upper) and compared using one-way ANOVA. Relationship between PM2.5 and cytokine levels was evaluated using generalized estimating equations (GEE). Results PM2.5 levels in the three categories differed significantly (lower: ≤22 μg/m3; middle: 23–37.5 μg/m3; upper: >37.5 μg/m3; p<0.001). The subjects from the two groups were distributed unevenly in the lower category (Group 1 = 8%; Group 2 = 92%), the middle category (Group 1 = 89%; Group 2 = 11%) and the upper category (Group 1 = 100%). A significant relationship was found between IL-5 and IL-10 and PM2.5 levels of the group 1, with an average decrease of 1.65 pg/mL of IL-5 level and of 0.78 pg/mL of IL-10 level in tear samples for each increment of 50 μg/m3 of PM2.5 (p = 0.01 and p = 0.003, respectively). Conclusion High levels of PM2.5 exposure is associated

  3. International comparison CCQM-K82: methane in air at ambient level (1800 to 2200) nmol/mol

    NASA Astrophysics Data System (ADS)

    Flores, Edgar; Viallon, Joële; Choteau, Tiphaine; Moussay, Philippe; Wielgosz, Robert I.; Kang, Namgoo; Kim, Byung Moon; Zalewska, Ewelina; H van der Veen, Adriaan (A. M.; Konopelko, Leonid; Wu, Hai; Han, Qiao; Rhoderick, George; Guenther, Franklin R.; Watanabe, Takuro; Shimosaka, Takuya; Kato, Kenji; Hall, Brad; Brewer, Paul

    2015-01-01

    The CCQM-K82 comparison was designed to evaluate the degrees of equivalence of NMI capabilities for methane in air primary reference mixtures in the range (1800 to 2200) nmol/mol. The balance gas for the standards was either scrubbed dry real air or synthetic air. CH4 in air standards have been produced by a number of laboratories for many years, with more recent developments focused on standards at atmospheric measurement concentrations and aimed at obtaining agreement between independently produced standards. A comparison of the differences in primary gas standards for methane in air was previously performed in 2003 (CCQM-P41 Greenhouse gases. 1 and 2) with a standard deviation of results around the reference value of 30 nmol/mol and 10 nmol/mol for a more limited set of standards. This can be contrasted with the level of agreement required from field laboratories routinely measuring atmospheric methane levels, set by Data Quality Objectives (DQO) established by the World Meteorological Organization (WMO) to reflect the scientifically desirable level of compatibility for CH4 measurements at the global scale, currently set at 2 nmol/mol (1 sigma). The measurements of this key comparison took place from May 2012 to June 2012. Eight laboratories took part in this comparison coordinated by the BIPM and NIST. Key comparison reference values were calculated based on Cavity Ring Down Spectroscopy Measurements performed at the BIPM, combined with participant's gravimetric values to identify a consistent set of standards. Regression analysis allowed predicted values for each standard to be calculated which acted as the KCRVs. In this comparison reported standard uncertainties by participants ranged from 0.50 nmol/mol to 2.4 nmol/mol and the uncertainties of individual KCRVs ranged from 0.68 nmol/mol to 0.71 nmol/mol. The standard deviation of the ensemble of standards about the KCRV value was 1.70 nmol/mol. This represents a greater than tenfold improvement in the level

  4. Understanding the Relationships between Air Pollution Levels and Human Health Outcomes

    EPA Science Inventory

    As mandated by the CAA, EPA established National Ambient Air Quality Standards (NAAQS) for criteria pollutants and conducts periodic review of the NAAQS to assess if they need to be revised. The CAA then provides for implementation of the NAAQS based on a combination of local con...

  5. Understanding the structure of hydrophobic surfactants at the air/water interface from molecular level.

    PubMed

    Zhang, Li; Liu, Zhipei; Ren, Tao; Wu, Pan; Shen, Jia-Wei; Zhang, Wei; Wang, Xinping

    2014-11-25

    Understanding the behavior of fluorocarbon surfactants at the air/water interface is crucial for many applications, such as lubricants, paints, cosmetics, and fire-fighting foams. In this study, molecular dynamics (MD) simulations were employed to investigate the microscopic properties of non-ionic fluorocarbon surfactants at the air/water interface. Several properties, including the distribution of head groups, the distribution probability of the tilt angle between hydrophobic tails with respect to the xy plane, and the order parameter of surfactants, were computed to probe the structure of hydrophobic surfactants at the air/water interface. The effects of the monomer structure on interfacial phenomena of non-ionic surfactants were investigated as well. It is observed that the structure of fluorocarbon surfactants at the air/water interface is more ordered than that of hydrocarbons, which is dominated by the van der Waals interaction between surfactants and water molecules. However, replacing one or two CF2 with one or two CH2 group does not significantly influence the interfacial structure, suggesting that hydrocarbons may be promising alternatives to perfluorinated surfactants.

  6. Air-climate-energy investigations with a state-level Integrated Assessment Model: GCAM-USA

    EPA Science Inventory

    The Global Change Assessment Model (GCAM) is a global integrated assessment model used for exploring future scenarios and examining strategies that address air pollution, climate change, and energy goals.  GCAM includes technology-rich representations of the energy, transportatio...

  7. But will I be re-elected? What happens to local level policy makers who support clean indoor air laws?

    PubMed

    Eisenberg, Merrill; McCotter, Orion; Sciacca, John

    2010-11-01

    This research was conducted to determine the impact of voting for clean indoor air ordinance on a local-level policy maker's re-election status. Secondary data were used to identify local tobacco ordinances in Arizona proposed between 2001 and 2005, score ordinance content for comprehensiveness, identify policy makers who voted and how they voted, and determine if the measure passed or failed. Participation in and outcomes of subsequent elections were documented from public records. Ninety-two local-level policy makers in 15 local jurisdictions considered clean indoor air laws between 2001 and 2005. Policy makers who voted for these ordinances were more likely to be re-elected than those who voted against them. Structured interviews revealed that policy makers did not believe the issue had an impact on re-election results and believed that although the issue may have been contentious, it was no longer salient in the community.

  8. [Noise level measurements of the air noise during drilling and grinding on the fresh isolated temporal bone (author's transl)].

    PubMed

    Paulsen, K; Vietor, K

    1975-10-01

    Aerial sound measurements with different drilling instruments were performed during dry running and preparations of the bone. Registered were the values of the small drilling instruments Sirona, Dentatus-Air, and Electro-Torque-Ritter. Also tested were the KaVo-Technique-machine, the Hall-machine, the Air-Orbit-turbine, and the Sirona-turbine. During dry running most of them already reached the allowed marginal value of noise nuisance for the ear of 85 dB (A) at a distance of 35 cm. Only the Air-Orbit-machine showed a slightly lower value of 80 dB (A). The level increases with the used handpieces. Normal handpieces 1:1 exert only a minimal influence, gear handpieces 2:1, however, markedly increase the level. The verticity is of no importance in the range of normal rotations between 10,000 r/min. and 80,000 r/min. Only rotations in the lower frequency range of 2,000 r/min. markedly decrease the noise level. During bone drilling, the kind and size of the drilling bit have an influence on the intensity of the noise level. Quadruple wing milling cutters create a very high noise level (at a distance of 15 cm still above 110 dB [A!]), big rose cutters (R 16) create noise levels of 95 dB (A) and above, and only diamond round bits create less noise (approximately 88 db [A]). Small drilling bits make such a faint noise, that it is overroared by the drilling instrument. The turbines create only slightly higher levels than during dry running. Larger drilling bits cannot be employed here on principle. Wing milling cutters can lead to persistent damages of the inner ear. The frequent use of dental drilling instruments for bone preparations can also lead to a hearing loss of the operator in the long run.

  9. The Development of a Computer-Directed Training Subsystem and Computer Operator Training Material for the Air Force Phase II Base Level System. Final Report.

    ERIC Educational Resources Information Center

    System Development Corp., Santa Monica, CA.

    The design, development, and evaluation of an integrated Computer-Directed Training Subsystem (CDTS) for the Air Force Phase II Base Level System is described in this report. The development and evaluation of a course to train computer operators of the Air Force Phase II Base Level System under CDTS control is also described. Detailed test results…

  10. Variation of annual effective dose due to radon level in indoor air in Marwar region of Rajasthan, India

    SciTech Connect

    Rani, Asha; Mittal, Sudhir; Mehra, Rohit

    2015-08-28

    In the present work, indoor radon and thoron measurements have been carried out from different locations of Jodhpur and Nagaur districts of Northern Rajasthan, India using RAD7, a solid state alpha detector. The radon and thoron concentration in indoor air varies from 8.75 to 61.25 Bq m{sup −3} and 32.7 to 147.2 Bq m{sup −3} with the mean value of 32 and 73 Bq m{sup −3} respectively. The observed indoor radon concentration values are well below the action level recommended by International Commission on Radiological Protection (200-300 Bq m{sup −3}) and Environmental Protection Agency (148 Bq m{sup −3}). The survey reveals that the thoron concentration values in the indoor air are well within the International Commission on Radiological Protection (2005). The calculated total annual effective dose due to radon level in indoor air varies from 0.22 to 1.54 mSv y{sup −1} with the mean value of 0.81 mSv y{sup −1} which is less than even the lower limit of action level 3-10 mSv y{sup −1} recommended by International Commission on Radiological Protection (2005)

  11. Mathematical estimation of the level of microbial contamination on spacecraft surfaces by volumetric air sampling

    NASA Technical Reports Server (NTRS)

    Oxborrow, G. S.; Roark, A. L.; Fields, N. D.; Puleo, J. R.

    1974-01-01

    Microbiological sampling methods presently used for enumeration of microorganisms on spacecraft surfaces require contact with easily damaged components. Estimation of viable particles on surfaces using air sampling methods in conjunction with a mathematical model would be desirable. Parameters necessary for the mathematical model are the effect of angled surfaces on viable particle collection and the number of viable cells per viable particle. Deposition of viable particles on angled surfaces closely followed a cosine function, and the number of viable cells per viable particle was consistent with a Poisson distribution. Other parameters considered by the mathematical model included deposition rate and fractional removal per unit time. A close nonlinear correlation between volumetric air sampling and airborne fallout on surfaces was established with all fallout data points falling within the 95% confidence limits as determined by the mathematical model.

  12. The Air Force Chief of Staff Logistics Review. Improving Wing-Level Logistics

    DTIC Science & Technology

    2005-01-01

    Force CSC2 Combat Support Execution Planning and Control CSL Core Support Location CWT Customer Wait Time DCM Deputy Commander for Maintenance DIFM Due In...Deputy Commander for Main- tenance ( DCM ) days, but this was not an option.3 Thus, major reor- ganization options were not within the scope of this effort.4...improved, and course durations increased. The senior workforce and management experience increased. The Air Force F-4 Phantom series aircraft was

  13. Flying-qualities criteria for wings-level-turn maneuvering during an air-to-ground weapon delivery task

    NASA Technical Reports Server (NTRS)

    Sammonds, R. I.; Bunnell, J. W.

    1981-01-01

    A moving base simulator experiment demonstrated that a wings-level-turn control mode improved flying qualities for air to ground weapon delivery compared with those of a conventionally controlled aircraft. Evaluations of criteria for dynamic response for this system have shown that pilot ratings correlate well on the basis of equivalent time constant of the initial response. Ranges of this time constant, as well as digital system transport delays and lateral acceleration control authorities that encompassed level 1 through 3 handling qualities, were determined.

  14. Air pollution and survival within the Washington University-EPRI Veterans Cohort: risks based on modelled estimates of ambient levels of hazardous and criteria air pollutants

    SciTech Connect

    Frederick W. Lipfert; Ronald E. Wyzga; Jack D. Baty; J. Philip Miller

    2009-04-15

    For this paper, we considered relationships between mortality, vehicular traffic density, and ambient levels of 12 hazardous air pollutants, elemental carbon (EC), oxides of nitrogen (NOx), sulfur dioxide (SO{sub 2}), and sulfate (SO{sub 4}{sup -2}). These pollutant species were selected as markers for specific types of emission sources, including vehicular traffic, coal combustion, smelters, and metal-working industries. Pollutant exposures were estimated using emissions inventories and atmospheric dispersion models. We analyzed associations between county ambient levels of these pollutants and survival patterns among approximately 70,000 U.S. male veterans by mortality period (1976-2001 and subsets), type of exposure model, and traffic density level. We found significant associations between all-cause mortality and traffic-related air quality indicators and with traffic density per se, with stronger associations for benzene, formaldehyde, diesel particulate, NOx, and EC. The maximum effect on mortality for all cohort subjects during the 26-yr follow-up period is approximately 10%, but most of the pollution-related deaths in this cohort occurred in the higher-traffic counties, where excess risks approach 20%. However, mortality associations with diesel particulates are similar in high- and low-traffic counties. Sensitivity analyses show risks decreasing slightly over time and minor differences between linear and logarithmic exposure models. We conclude that tailpipe emissions of both gases and particles are among the most significant and robust predictors of mortality in this cohort and that most of those associations have weakened over time. There may be concerns associated with large stationary sources burning coal, residual fuel oil and municipal solid wastes. Nickel and arsenic have been identified in coal fly ash and residual oil. 81 refs., 3 figs., 7 tabs.

  15. Assessing levels of POPs in air over the South Atlantic Ocean off the coast of South America.

    PubMed

    Pegoraro, César N; Harner, Tom; Su, Ky; Chiappero, Malisa S

    2016-11-15

    The occurrence of persistent organic pollutants (POPs) in the atmosphere of the near-coast South Atlantic Ocean was studied. Air samples were collected using a high-volume air sampler (filter and polyurethane foam) on board the Argentinean research cruise R/V Puerto Deseado (CONICET). Samples were analyzed for 50 polychlorinated biphenyl (PCBs), 22 organochlorine pesticides (OCPs) and 14 polybrominated diphenyl ethers (PBDEs). These POPs classes showed a trend of decreasing levels from near-shore to open ocean sites. OCPs and PCBs were in the same order of magnitude (2.71-87.1pg/m(3) and 9.56-130pg/m(3), respectively) while PBDEs levels were significantly lower (0.69-2.58pg/m(3)). Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, chlordanes, hexachlorocyclohexanes (HCHs) and heptachlors were between 0.20 and 17.8pg/m(3), while drines and hexachlorobenzene (HCB) were at lower levels (0.28-3.71pg/m(3)). The most frequently detected PCBs were congeners 32, 28, 44, 52, 95, representing >50% of the total. The PBDEs congener pattern was dominated by congener 209 (70%), followed by 47 and 99 (16% and 7%, respectively). Air parcel back trajectories for the study period provided few insights as trajectories mainly stemmed from the open ocean with limited inputs from continental sources. These results indicate that the concentration of POPs (namely PCBs, OCPs, and PBDEs) in air remain elevated in the near-shore environment and then drop-off substantially beyond a distance of about 400km. This has implications for the loading of POPs and delivery to the marine environment in the near coastal zone.

  16. A gravimetric approach to providing SI traceability for concentration measurement results of mercury vapor at ambient air levels

    NASA Astrophysics Data System (ADS)

    Ent, Hugo; van Andel, Inge; Heemskerk, Maurice; van Otterloo, Peter; Bavius, Wijnand; Baldan, Annarita; Horvat, Milena; Brown, Richard J. C.; Quétel, Christophe R.

    2014-11-01

    Current measurement and calibration capabilities for mercury vapor in air are maintained at levels of 0.2-40 μg Hg m-3. In this work, a mercury vapor generator has been developed to establish metrological traceability to the international system of units (SI) for mercury vapor measurement results ≤15 ng Hg m-3, i.e. closer to realistic ambient air concentrations (1-2 ng Hg m-3) [1]. Innovations developed included a modified type of diffusion cell, a new measurement method to weigh the loss in (mercury) mass of these diffusion cells during use (ca. 6-8 μg mass difference between successive weighings), and a new housing for the diffusion cells to maximize flow characteristics and to minimize temperature variations and adsorption effects. The newly developed mercury vapor generator system was tested by using diffusion cells generating 0.8 and 16 ng Hg min-1. The results also show that the filter system, to produce mercury free air, is working properly. Furthermore, and most importantly, the system is producing a flow with a stable mercury vapor content. Some additional improvements are still required to allow the developed mercury vapor generator to produce SI traceable mercury vapor concentrations, based upon gravimetry, at much lower concentration levels and reduced measurement uncertainties than have been achieved previously. The challenges to be met are especially related to developing more robust diffusion cells and better mass measurement conditions. The developed mercury vapor generator will contribute to more reliable measurement results of mercury vapor at ambient and background air levels, and also to better safety standards and cost reductions in industrial processes, such as the liquefied natural gas field, where aluminum main cryogenic heat exchangers are used which are particularly prone to corrosion caused by mercury.

  17. Investigation of indoor air volatile organic compounds concentration levels in dental settings and some related methodological issues.

    PubMed

    Santarsiero, Anna; Fuselli, Sergio; Piermattei, Alessandro; Morlino, Roberta; De Blasio, Giorgia; De Felice, Marco; Ortolani, Emanuela

    2009-01-01

    The assessment of indoor air volatile organic compounds (VOCs) concentration levels in dental settings has a big health relevance for the potentially massive occupational exposure to a lot of diverse contaminants. The comparison of the VOCs profile relative to indoor conditions and to the corresponding outdoor concentrations, as well as the discovery of possible correlations between specific dental activities and VOCs concentration variations are of utmost importance for offering a reliable characterization of risk for dentists and dental staff health. In this study we review the most relevant environmental studies addressing the VOCs contamination level in dental settings. We analyze the methodological problems this kind of study must face and we report preliminary results of an indoor air investigation, carried out at dental hospital in Italy, the "Ospedale odontoiatrico George Eastman" of Rome, in which general lines for the analysis of dental settings in environmental terms are sketched. The aim of this work is to identify the kind of problems a typical enclosed (non-industrial) environment indoor air investigation has to cope with by means of the analysis of a case study.

  18. Comparison of background levels of culturable fungal spore concentrations in indoor and outdoor air in southeastern Austria

    NASA Astrophysics Data System (ADS)

    Haas, D.; Habib, J.; Luxner, J.; Galler, H.; Zarfel, G.; Schlacher, R.; Friedl, H.; Reinthaler, F. F.

    2014-12-01

    Background concentrations of airborne fungi are indispensable criteria for an assessment of fungal concentrations indoors and in the ambient air. The goal of this study was to define the natural background values of culturable fungal spore concentrations as reference values for the assessment of moldy buildings. The concentrations of culturable fungi were determined outdoors as well as indoors in 185 dwellings without visible mold, obvious moisture problems or musty odor. Samples were collected using the MAS-100® microbiological air sampler. The study shows a characteristic seasonal influence on the background levels of Cladosporium, Penicillium and Aspergillus. Cladosporium sp. had a strong outdoor presence, whereas Aspergillus sp. and Penicillium sp. were typical indoor fungi. For the region of Styria, the median outdoor concentrations are between 100 and 940 cfu/m³ for culturable xerophilic fungi in the course of the year. Indoors, median background levels are between 180 and 420 cfu/m³ for xerophilic fungi. The I/O ratios of the airborne fungal spore concentrations were between 0.2 and 2.0. For the assessment of indoor and outdoor air samples the dominant genera Cladosporium, Penicillium and Aspergillus should receive special consideration.

  19. China's air pollution reduction efforts may result in an increase in surface ozone levels in highly polluted areas.

    PubMed

    Anger, Annela; Dessens, Olivier; Xi, Fengming; Barker, Terry; Wu, Rui

    2016-03-01

    China, as a fast growing fossil-fuel-based economy, experiences increasing levels of air pollution. To tackle air pollution, China has taken the first steps by setting emission-reduction targets for nitrogen oxides (NO x ) and sulphur dioxide (SO2) in the 11th and 12th Five Year Plans. This paper uses two models-the Energy-Environment-Economy Model at the Global level (E3MG) and the global Chemistry Transport Model pTOMCAT-to test the effects of these policies. If the policy targets are met, then the maximum values of 32 % and 45 % reductions below 'business as usual' in the monthly mean NO x and SO2 concentrations, respectively, will be achieved in 2015. However, a decrease in NO x concentrations in some highly polluted areas of East, North-East and South-East China can lead to up to a 10% increase in the monthly mean concentrations in surface ozone in 2015. Our study demonstrates an urgent need for the more detailed analysis of the impacts and designs of air pollution reduction guidelines for China.

  20. Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate.

    PubMed

    Johnston, J D; Kruman, B A; Nelson, M C; Merrill, R M; Graul, R J; Hoybjerg, T G; Tuttle, S C; Myers, S J; Cook, R B; Weber, K S

    2017-01-31

    Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m(2) ) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m(2) were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes.

  1. Piloted simulation of one-on-one helicopter air combat at NOE flight levels

    NASA Technical Reports Server (NTRS)

    Lewis, M. S.; Aiken, E. W.

    1985-01-01

    A piloted simulation designed to examine the effects of terrain proximity and control system design on helicopter performance during one-on-one air combat maneuvering (ACM) is discussed. The NASA Ames vertical motion simulator (VMS) and the computer generated imagery (CGI) systems were modified to allow two aircraft to be independently piloted on a single CGI data base. Engagements were begun with the blue aircraft already in a tail-chase position behind the red, and also with the two aircraft originating from positions unknown to each other. Maneuvering was very aggressive and safety requirements for minimum altitude, separation, and maximum bank angles typical of flight test were not used. Results indicate that the presence of terrain features adds an order of complexiaty to the task performed over clear air ACM and that mix of attitude and rate command-type stability and control augmentation system (SCAS) design may be desirable. The simulation system design, the flight paths flown, and the tactics used were compared favorably by the evaluation pilots to actual flight test experiments.

  2. School-based exposure to hazardous air pollutants and grade point average: A multi-level study.

    PubMed

    Grineski, Sara E; Clark-Reyna, Stephanie E; Collins, Timothy W

    2016-05-01

    The problem of environmental health hazards around schools is serious but it has been neglected by researchers and analysts. This is concerning because children are highly susceptible to the effects of chemical hazards. Some ecological studies have demonstrated that higher school-level pollution is associated with lower aggregate school-level standardized test scores likely, related to increased respiratory illnesses and/or impaired cognitive development. However, an important question remains unexamined: How do school-level exposures impact individual children's academic performance? To address this, we obtained socio-demographic and grades data from the parents of 1888 fourth and fifth grade children in the El Paso (Texas, USA) Independent School District in 2012. El Paso is located on the US-side of the Mexican border and has a majority Mexican-origin population. School-based hazardous air pollution (HAP) exposure was calculated using census block-level US Environmental Protection Agency National Air Toxics Assessment risk estimates for respiratory and diesel particulate matter (PM). School-level demographics were obtained from the school district. Multi-level models adjusting for individual-level covariates (e.g., age, sex, race/ethnicity, English proficiency, and economic deprivation) and school-level covariates (e.g., percent of students economically disadvantaged and student-teacher ratio) showed that higher school-level HAPs were associated with lower individual-level grade point averages. An interquartile range increase in school-level HAP exposure was associated with an adjusted 0.11-0.40 point decrease in individual students' grade point averages (GPAs), depending on HAP type and emission source. Respiratory risk from HAPs had a larger effect on GPA than did diesel PM risk. Non-road mobile and total respiratory risk had the largest effects on children's GPA of all HAP variables studied and only mother's level of education had a larger effect than those

  3. Levels and pattern of alkyl nitrates, multifunctional alkyl nitrates, and halocarbons in the air over the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Fischer, Ralf G.; Kastler, Jürgen; Ballschmiter, Karlheinz

    2000-06-01

    The Albatross Campaign was a research cruise of the German research vessel RV Polarstern (cruise ANT XFV/1) in October and November 1996 across the Atlantic Ocean. The cruise started in Bremerhaven, Germany, reached the polar region at 67°N, followed the 30°W meridian longitude, crossed the equatorial region, and ended at 50°S at Punta Quilla, Argentina. A second cruise leg closer to the African continent started from Capetown, South Africa, passed the Canary Island, and ended through the English Channel at Bremerhaven, Germany, in May/June 1998. Measurements of atmospheric levels of C1-C13 alkyl mononitrates, 24 alkyl dinitrates (C3-C6), 19 hydroxy alkyl nitrates (C2-C6), and benzyl nitrate, as well as the halocarbons tetrachloroethene, hexachloroethane, and bromoform are presented in this work. The halocarbons are used to assess the origin of the air parcels analyzed. Levels and patterns of multifunctional alkyl nitrates in the marine air are described here for the first time. The air masses include polluted air from the northern Europe, as well as highly degraded air masses of the South Atlantic trade wind region that represent global baseline levels. Two independent analytical methods were used in combination to cover the whole range of organic nitrates. First, the low-volume adsorptive enrichment of organic traces on Tenax, followed by thermodesorption cold trap HRGC-ECD and thermodesorption cold trap HRGC-(EI)MSD was used. Second, high-volume adsorptive enrichment of organic traces on silica gel was applied followed by solvent desorption, NP-HPLC group separation, and HRGC-(EI)-MSD. Short-chain alkyl nitrates (C4-C6) showed mixing ratios in the range of 0.2-2.5 parts per trillion by volume (pptv), with a local minimum for the tropical regions and significantly lower ratios for the Southern Hemisphere. The mixing ratio of the sum of 36 long-chain alkyl mononitrates (C7-C13) ranged from 0.02-0.43 pptv, the mixing ratio of the sum of 23 alkyl dinitrates (C3-C

  4. Modeling the global levels and distribution of polychlorinated biphenyls in air under a climate change scenario.

    PubMed

    Lamon, Lara; Von Waldow, Harald; Macleod, Matthew; Scheringer, Martin; Marcomini, Antonio; Hungerbühler, Konrad

    2009-08-01

    We used the multimedia chemical fate model BETR Global to evaluate changes in the global distribution of two polychlorinated biphenyls, PCB 28 and PCB 153, under the influence of climate change. This was achieved by defining two climate scenarios based on results from a general circulation model, one scenario representing the last twenty years of the 20th century (20CE scenario) and another representing the global climate under the assumption of strong future greenhouse gas emissions (A2 scenario). The two climate scenarios are defined by four groups of environmental parameters: (1) temperature in the planetary boundary layer and the free atmosphere, (2) wind speeds and directions in the atmosphere, (3) current velocities and directions in the surface mixed layer of the oceans, and (4) rate and geographical pattern of precipitation. As a fifth parameter in our scenarios, we considerthe effect of temperature on primary volatilization emissions of PCBs. Comparison of dynamic model results using environmental parameters from the 20CE scenario against historical long-term monitoring data of concentrations of PCB 28 and PCB 153 in air from 16 different sites shows satisfactory agreement between modeled and measured PCBs concentrations. The 20CE scenario and A2 scenario were compared using steady-state calculations and assuming the same source characteristics of PCBs. Temperature differences between the two scenarios is the dominant factor that determines the difference in PCB concentrations in air. The higher temperatures in the A2 scenario drive increased primary and secondary volatilization emissions of PCBs, and enhance transport from temperate regions to the Arctic. The largest relative increase in concentrations of both PCB congeners in air under the A2 scenario occurs in the high Arctic and the remote Pacific Ocean. Generally, higher wind speeds under the A2 scenario result in more efficient intercontinental transport of PCB 28 and PCB 153 compared to the 20CE

  5. Assessment of health-cost externalities of air pollution at the national level using the EVA model system

    NASA Astrophysics Data System (ADS)

    Brandt, J.; Frohn, L. M.; Christensen, J. H.; Andersen, M. S.; Hertel, O.; Geels, C.; Buus Hansen, A.; Hansen, K. M.; Hedegaard, G. B.; Skjøth, C. A.

    2009-04-01

    An integrated model system EVA (Economic Valuation of Air pollution) has been developed to assess external costs related to air pollution from individual sources as specific power plants or different emission sectors, as e.g. power production, road traffic, farming etc. The EVA system is based on the impact pathway chain and consists of a regional scale non-linear Eulerian atmospheric transport-chemistry model including detailed emissions inventories (the Danish Eulerian Hemispheric Model, DEHM), address-level or gridded population data, state-of-the-art exposure-response functions and monetary valuation of the impacts from air pollution. The first general assessment of health-cost externalities at the national level using the EVA system is presented here. Health-cost externalities from different emission sectors in Denmark e.g. power production, road traffic, as well as all sectors simultaneously have been calculated. Furthermore, the heath-cost externalities based on emissions from international ship traffic in the Baltic Sea as well as the North Sea have been estimated. Examples of delta functions, human exposure levels and the total costs of impacts from different chemical species are given. The work is partly carried out within the Centre for Energy, Environment and Health (www.CEEH.dk), which is a Danish strategic research centre funded by the Danish Council for Strategic Research. The mission of the centre is to develop a system to support planning of future energy systems in Denmark, where both direct and indirect costs related to environment, climate and health are considered.

  6. An inorganic carbon transport system responsible for acclimation specific to air levels of CO2 in Chlamydomonas reinhardtii.

    PubMed

    Wang, Yingjun; Spalding, Martin H

    2006-06-27

    Many photosynthetic microorganisms acclimate to CO(2) limited environments by induction and operation of CO(2)-concentrating mechanisms (CCMs). Despite their central role in CCM function, inorganic carbon (Ci) transport systems never have been identified in eukaryotic photosynthetic organisms. In the green alga Chlamydomonas reinhardtii, a mutant, pmp1, was described in 1983 with deficiencies in Ci transport, and a Pmp1 protein-associated Ci uptake system has been proposed to be responsible for Ci uptake in low CO(2) (air level)-acclimated cells. However, even though pmp1 represents the only clear genetic link to Ci transport in microalgae and is one of only a very few mutants directly affecting the CCM itself, the identity of Pmp1 has remained unknown. Physiological analyses indicate that C. reinhardtii possesses multiple Ci transport systems responsible for acclimation to different levels of limiting CO(2) and that the Pmp1-associated transport system is required specifically for low (air level) CO(2) acclimation. In the current study, we identified and characterized a pmp1 allelic mutant, air dier 1 (ad1) that, like pmp1, cannot grow in low CO(2) (350 ppm) but can grow either in high CO(2) (5% CO(2)) or in very low CO(2) (<200 ppm). Molecular analyses revealed that the Ad1/Pmp1 protein is encoded by LciB, a gene previously identified as a CO(2)-responsive gene. LciB and three related genes in C. reinhardtii compose a unique gene family that encode four closely related, apparently soluble plastid proteins with no clearly identifiable conserved motifs.

  7. Evaluation of elemental content in air-borne particulate matter in low-level atmosphere of Bratislava

    NASA Astrophysics Data System (ADS)

    Merešová, J.; Florek, M.; Holý, K.; Ješkovský, M.; Sýkora, I.; Frontasyeva, M. V.; Pavlov, S. S.; Bujdoš, M.

    A one-year study on total air-borne particulate matter has been undertaken in the framework of air pollution project in Bratislava. The 16 filter samples were collected in 2004 in order to evaluate the level of pollution and assess the potential environmental hazards in Bratislava. As a result of two irradiations with neutrons and four gamma-spectrometric measurements the concentrations of 30 chemical elements (Na, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Ga, As, Se, Br, Rb, In, Sb, I, Cs, Ba, La, Sm, Dy, Tm, W, Au, Hg, Th, U) were determined using instrumental neutron activation analysis (INAA). Additionally the concentrations of other six elements (Cr, Ni, Cu, Zn, Cd, Pb) were measured by atomic absorption spectrometry (AAS). The comparison with other European cities was carried out. Crustal enrichment factors were calculated in order to distinguish the possible sources of air-borne particulate matter. For some elements elevated concentrations were observed for the summer months. The other concentrations were relatively stable over the year.

  8. Patient radiation doses in interventional cardiology in the U.S.: Advisory data sets and possible initial values for U.S. reference levels

    SciTech Connect

    Miller, Donald L.; Hilohi, C. Michael; Spelic, David C.

    2012-10-15

    Purpose: To determine patient radiation doses from interventional cardiology procedures in the U.S and to suggest possible initial values for U.S. benchmarks for patient radiation dose from selected interventional cardiology procedures [fluoroscopically guided diagnostic cardiac catheterization and percutaneous coronary intervention (PCI)]. Methods: Patient radiation dose metrics were derived from analysis of data from the 2008 to 2009 Nationwide Evaluation of X-ray Trends (NEXT) survey of cardiac catheterization. This analysis used deidentified data and did not require review by an IRB. Data from 171 facilities in 30 states were analyzed. The distributions (percentiles) of radiation dose metrics were determined for diagnostic cardiac catheterizations, PCI, and combined diagnostic and PCI procedures. Confidence intervals for these dose distributions were determined using bootstrap resampling. Results: Percentile distributions (advisory data sets) and possible preliminary U.S. reference levels (based on the 75th percentile of the dose distributions) are provided for cumulative air kerma at the reference point (K{sub a,r}), cumulative air kerma-area product (P{sub KA}), fluoroscopy time, and number of cine runs. Dose distributions are sufficiently detailed to permit dose audits as described in National Council on Radiation Protection and Measurements Report No. 168. Fluoroscopy times are consistent with those observed in European studies, but P{sub KA} is higher in the U.S. Conclusions: Sufficient data exist to suggest possible initial benchmarks for patient radiation dose for certain interventional cardiology procedures in the U.S. Our data suggest that patient radiation dose in these procedures is not optimized in U.S. practice.

  9. Intra-urban spatial variability in wintertime street-level concentrations of multiple combustion-related air pollutants: the New York City Community Air Survey (NYCCAS).

    PubMed

    Clougherty, Jane E; Kheirbek, Iyad; Eisl, Holger M; Ross, Zev; Pezeshki, Grant; Gorczynski, John E; Johnson, Sarah; Markowitz, Steven; Kass, Daniel; Matte, Thomas

    2013-01-01

    Although intra-urban air pollution differs by season, few monitoring networks provide adequate geographic density and year-round coverage to fully characterize seasonal patterns. Here, we report winter intra-urban monitoring and land-use regression (LUR) results from the New York City Community Air Survey (NYCCAS). Two-week integrated samples of fine particles (PM(2.5)), black carbon (BC), nitrogen oxides (NO(x)) and sulfur dioxide (SO(2)) were collected at 155 city-wide street-level locations during winter 2008-2009. Sites were selected using stratified random sampling, randomized across sampling sessions to minimize spatio-temporal confounding. LUR was used to identify GIS-based source indicators associated with higher concentrations. Prediction surfaces were produced using kriging with external drift. Each pollutant varied twofold or more across sites, with higher concentrations near midtown Manhattan. All pollutants were positively correlated, particularly PM(2.5) and BC (Spearman's r=0.84). Density of oil-burning boilers, total and truck traffic density, and temporality explained 84% of PM(2.5) variation. Densities of total traffic, truck traffic, oil-burning boilers and industrial space, with temporality, explained 65% of BC variation. Temporality, built space, bus route location, and traffic density described 67% of nitrogen dioxide variation. Residual oil-burning units, nighttime population and temporality explained 77% of SO(2) variation. Spatial variation in combustion-related pollutants in New York City was strongly associated with oil-burning and traffic density. Chronic exposure disparities and unique local sources can be identified through year-round saturation monitoring.

  10. On evaluating compliance with air pollution levels 'not to be exceeded more than once a year'

    NASA Technical Reports Server (NTRS)

    Neustadter, H. E.; Sidik, S. M.

    1974-01-01

    Under a sampling program operated in conformity with EPA guidelines, calculational procedures are described for estimating the corresponding ambient pollution level. The statistical independence of the data, the commutativity of expectation and exponential operations, and the statistical variability of the calculated results are quantitatively evaluated. It is shown that the recommended sampling frequencies of every third to every sixth day are inadequate in determining conformity when the standards are expressed as levels not to be exceeded more than once a year.

  11. ETS levels in hospitality environments satisfying ASHRAE standard 62-1989: "ventilation for acceptable indoor air quality"

    NASA Astrophysics Data System (ADS)

    Moschandreas, D. J.; Vuilleumier, K. L.

    Prior to this study, indoor air constituent levels and ventilation rates of hospitality environments had not been measured simultaneously. This investigation measured indoor Environmental Tobacco Smoke-related (ETS-related) constituent levels in two restaurants, a billiard hall and a casino. The objective of this study was to characterize ETS-related constituent levels inside hospitality environments when the ventilation rates satisfy the requirements of the ASHRAE 62-1989 Ventilation Standard. The ventilation rate of each selected hospitality environment was measured and adjusted. The study advanced only if the requirements of the ASHRAE 62-1989 Ventilation Standard - the pertinent standard of the American Society of Heating, Refrigeration and Air Conditioning Engineers - were satisfied. The supply rates of outdoor air and occupant density were measured intermittently to assure that the ventilation rate of each facility satisfied the standard under occupied conditions. Six ETS-related constituents were measured: respirable suspended particulate (RSP) matter, fluorescent particulate matter (FPM, an estimate of the ETS particle concentrations), ultraviolet particulate matter (UVPM, a second estimate of the ETS particle concentrations), solanesol, nicotine and 3-ethenylpyridine (3-EP). ETS-related constituent levels in smoking sections, non-smoking sections and outdoors were sampled daily for eight consecutive days at each hospitality environment. This study found that the difference between the concentrations of ETS-related constituents in indoor smoking and non-smoking sections was statistically significant. Differences between indoor non-smoking sections and outdoor ETS-related constituent levels were identified but were not statistically significant. Similarly, differences between weekday and weekend evenings were identified but were not statistically significant. The difference between indoor smoking sections and outdoors was statistically significant. Most

  12. Reduction of air pollution levels downwind of a road with an upwind noise barrier

    NASA Astrophysics Data System (ADS)

    Enayati Ahangar, Faraz; Heist, David; Perry, Steven; Venkatram, Akula

    2017-04-01

    We propose a dispersion model to estimate the impact of a solid noise barrier upwind of a highway on air pollution concentrations downwind of the road. The model, based on data from wind tunnel experiments conducted by Heist et al. (2009), assumes that the upwind barrier has two main effects: 1) it creates a recirculation zone behind the barrier that sweeps the emissions from the highway back towards the wall, and 2) it enhances vertical dispersion and initial mixing. By combining the upwind barrier model with the mixed wake model for a downwind barrier described in Schulte et al. (2014), we are able to model dispersion of emissions from a highway with noise barriers on both sides. The model provides a good description of measurements made in the wind tunnel. The presence of an upwind barrier causes reductions in concentrations relative to those measured downwind of a road with no barriers. The reduction can be as large as that caused by a downwind barrier if the recirculation zone covers the width of the highway. Barriers on both sides of the highway result in larger reductions downwind of the barriers than those caused by a single barrier either upwind or downwind. As expected, barrier effects are small beyond 10 barrier heights downwind of the highway. We also propose a tentative model to estimate on-road concentrations within the recirculation zone induced by the upwind barrier.

  13. Effects of air pollution on Pinus halepensis (Mill.): pollution levels in Attica, Greece

    NASA Astrophysics Data System (ADS)

    Velissariou, D.; Davison, A. W.; Barnes, J. D.; Pfirrmann, T.; Maclean, D. C.; Holevas, C. D.

    Air quality in the Athens basin is well known to be poor, damaging building materials and human health, but there is no information available on concentrations or the impact of oxidants on ecosystems in rural areas outside the basin. A short-term monitoring campaign, coupled with a survey using the O 3 bioindicator Bel-W3 tobacco demonstrated that phytotoxic concentrations of O 3 occurred throughout Attica, within a 75 km radius of the city. There was relatively little injury produced in the industrial centre of the city and maximum injury was found about 40 km to the SE. Visible lesions identical to those of O 3 injury were found on Aleppo pine at all sites in the cooler months. In the summer the needles were very chlorotic, possibly due to photo-oxidation of chlorophylls mediated by heat or drought. This chlorosis may mask oxidant symptoms in the summer. NO 2 diffusion tube data and needle analysis suggested that the effects of sulphur and NO 2 are probably confined to the Athens basin.

  14. Air Nicotine Levels in Public Places in Ahmedabad, India: Before and After Implementation of the Smoking Ban

    PubMed Central

    Yang, Jingyan; Modi, Bhavesh V.; Tamplin, Stephen A.; Aghi, Mira B.; Dave, Paresh V.; Cohen, Joanna E.

    2015-01-01

    Aim: To compare air nicotine levels in public places in Ahmedabad, India, before (June 2008) and after (January, 2010) the implementation of a comprehensive smoking ban which was introduced in October 2008. Materials and Methods: Air nicotine concentrations were measured by sampling of vapor-phase nicotine using passive monitors. In 2008 (baseline), monitors were placed for 5-7 working days in 5 hospitals, 10 restaurants, 5 schools, 5 government buildings, and 10 entertainment venues, of which 6 were hookah bars. In 2010 (follow-up), monitors were placed in 35 similar venues for the same duration. Results: Comparison of the overall median nicotine concentration at baseline (2008) (0.06 μg/m3 Interquartile range (IQR): 0.02-0.22) to that of follow-up (2010) (0.03 μg/m3 IQR: 0.00-0.13), reflects a significant decline (% decline = 39.7, P = 0.012) in exposure to second-hand smoke (SHS). The percent change in exposure varied by venue-type. The most significant decrease occurred in hospitals, from 0.04 μg/m3 at baseline to concentrations under the limit of detection at follow-up (%decline = 100, P < 0.001). In entertainment venues, government offices, and restaurants, decreases in SHS exposure also appeared evident. However, in hookah bars, air nicotine levels appeared to increase (P = 0.160). Conclusion: Overall, SHS exposure was significantly reduced in public places after the smoke-free legislation came into force. However, nicotine concentrations were still detected in most of the venues indicating imperfect compliance with the comprehensive ban. PMID:25657509

  15. Air and blood lead levels in lead acid battery recycling and manufacturing plants in Kenya.

    PubMed

    Were, Faridah H; Kamau, Geoffrey N; Shiundu, Paul M; Wafula, Godfrey A; Moturi, Charles M

    2012-01-01

    The concentration of airborne and blood lead (Pb) was assessed in a Pb acid battery recycling plant and in a Pb acid battery manufacturing plant in Kenya. In the recycling plant, full-shift area samples taken across 5 days in several production sections showed a mean value ± standard deviation (SD) of 427 ± 124 μg/m(3), while area samples in the office area had a mean ± SD of 59.2 ± 22.7 μg/m(3). In the battery manufacturing plant, full-shift area samples taken across 5 days in several production areas showed a mean value ± SD of 349 ± 107 μg/m(3), while area samples in the office area had a mean ± SD of 55.2 ± 33.2 μg/m(3). All these mean values exceed the U.S. Occupational Safety and Health Administration's permissible exposure limit of 50 μg/m(3) as an 8-hr time-weighted average. In the battery recycling plant, production workers had a mean blood Pb level ± SD of 62.2 ± 12.7 μg/dL, and office workers had a mean blood Pb level ± SD of 43.4 ± 6.6 μg/dL. In the battery manufacturing plant, production workers had a mean blood Pb level ± SD of 59.5 ± 10.1 μg/dL, and office workers had a mean blood Pb level ± SD of 41.6 ± 7.4 μg/dL. All the measured blood Pb levels exceeded 30 μg/dL, which is the maximum blood Pb level recommended by the ACGIH(®). Observations made in these facilities revealed numerous sources of Pb exposure due to inadequacies in engineering controls, work practices, respirator use, and personal hygiene.

  16. Human occupations and environmental changes in the Nile valley during the Holocene: The case of Kerma in Upper Nubia (northern Sudan)

    NASA Astrophysics Data System (ADS)

    Honegger, Matthieu; Williams, Martin

    2015-12-01

    Our article presents a detailed Holocene archaeological sequence from the Nile Valley at Kerma in Upper Nubia, northern Sudan. This sequence retraces the evolution of human populations thanks to the study of several sites, supported by 90 14C dates. Reconstruction of the environmental changes was supported by a study of dated stratigraphic sections located near the archaeological sites studied, and illustrates the effects on human occupation of changes in river flow and floods, which are in turn forced by climatic changes. The results shed new light on the evolutionary dynamics of the Holocene populations in Nile Valley, little known due to the numerous hiatuses in occupation. When compared with the situation in the Sahara and the rest of the Nile Valley, they confirm that the initial occupation took place ca. 10.5 kyr BP after the start of the African Humid Period, followed by a migration towards the banks of the Nile commencing 7.3 kyr BP. They also confirm the appearance of the Neolithic by ca. 8.0 kyr BP. The Kerma stratigraphic sequences show two prosperous periods (10-8 and 7-6 kyr BP) and two hiatuses in the occupation of the sites (7.5-7.1 and 6.0-5.4 kyr BP), resulting from increased aridity.

  17. Photon and neutron fluence-to-kerma conversion factors for ICRP-1975 reference man using improved elemental compositions for bone and marrow of the skeleton

    SciTech Connect

    Kerr, G.D.

    1982-11-01

    A twelve-element approximation of the total-body, soft-tissue and skeletal components of ICRP-1975 Reference Man is used to investigate particle fluence-to-kerma conversion factors for photons with energies between 1 keV and 20 MeV and neutrons with energies between 0.0253 eV and 20 MeV. Several recent ICRP revisions to the elemental composition of Reference Man, which have not been included in other kerma-factor calculations, are taken into account. This work suggests some additional revisions to the major-element content (i.e., H, C, N, and O) and to the mineral and trace-element content (i.e., Na, Mg, P, S, Cl, K, Ca, and Fe) of various total-body, soft-tissue, and skeletal components of Reference Man. The revisions to the bone and red marrow of the skeleton offer significant new refinements in red-bone-marrow dosimetry.

  18. Regional Joint-Integrated Air and Missile Defense (RF-IAMD): An Operational Level Integrated Air and Missile Defense (IAMD) Command and Control (C2) Organization

    DTIC Science & Technology

    2015-05-15

    attempt to balance various competing interests against the commander’s guidance and stated objectives. In this process targets are nominated...apportionment recommendations and decisions: the Joint Air Operations Plan (JAOP) and Air Operations Directive ( AOD ). 12...the JFACC’s plan to integrate and coordinate operations across all the phases of air power (0 through 5). The AOD is the JFACC’s written guidance which

  19. The Effects of Organizational Level, Sex, and Race on Air Force Organizational Effectiveness.

    DTIC Science & Technology

    1981-09-01

    for their invaluable assistance with the data analysis aspects of this research, To my wife, Barbara, and my daughter, Erin Michelle , I express my...Advancement to a higher level may not be a motivator if the individual’s needs, interests, or abilities are not congruent with the job ( Hulin , 1971; Holland

  20. Map of the Field--Higher Education Research at the State Level. AIR Forum 1982 Paper.

    ERIC Educational Resources Information Center

    Crosson, Patricia H.; Adams, Charles S.

    A map of the field of higher education at the state level is presented that defines theoretical and conceptual frameworks, approaches to analysis, research designs, and methodologies that have been used in the study of the relationships between state governments and institutions of higher education or of state policy structures and processes.…

  1. A Comprehensive Technique for Forecasting University Enrollment, Instructional Workloads and Funding Levels. AIR Forum 1980 Paper.

    ERIC Educational Resources Information Center

    Lasher, William F.; And Others

    Analytical techniques developed by the University of Texas at Austin to deal with problems of forecasting future enrollments, instructional workloads, and funding levels are considered. In order to project university enrollments, Texas public high school graduates were projected. In-migration rates were separated from survival rates,…

  2. Nanosecond-level time synchronization of autonomous radio detector stations for extensive air showers

    SciTech Connect

    Aab, Alexander

    2016-01-29

    To exploit the full potential of radio measurements of cosmic-ray air showers at MHz frequencies, a detector timing synchronization within 1 ns is needed. Large distributed radio detector arrays such as the Auger Engineering Radio Array (AERA) rely on timing via the Global Positioning System (GPS) for the synchronization of individual detector station clocks. Unfortunately, GPS timing is expected to have an accuracy no better than about 5 ns. In practice, in particular in AERA, the GPS clocks exhibit drifts on the order of tens of ns. We developed a technique to correct for the GPS drifts, and an independent method used for cross-checks that indeed we reach nanosecond-scale timing accuracy by this correction. First, we operate a “beacon transmitter” which emits defined sine waves detected by AERA antennas recorded within the physics data. The relative phasing of these sine waves can be used to correct for GPS clock drifts. In addition to this, we observe radio pulses emitted by commercial airplanes, the position of which we determine in real time from Automatic Dependent Surveillance Broadcasts intercepted with a software-defined radio. From the known source location and the measured arrival times of the pulses we determine relative timing offsets between radio detector stations. We demonstrate with a combined analysis that the two methods give a consistent timing calibration with an accuracy of 2 ns or better. Consequently, the beacon method alone can be used in the future to continuously determine and correct for GPS clock drifts in each individual event measured by AERA.

  3. Nanosecond-level time synchronization of autonomous radio detector stations for extensive air showers

    DOE PAGES

    Aab, Alexander

    2016-01-29

    To exploit the full potential of radio measurements of cosmic-ray air showers at MHz frequencies, a detector timing synchronization within 1 ns is needed. Large distributed radio detector arrays such as the Auger Engineering Radio Array (AERA) rely on timing via the Global Positioning System (GPS) for the synchronization of individual detector station clocks. Unfortunately, GPS timing is expected to have an accuracy no better than about 5 ns. In practice, in particular in AERA, the GPS clocks exhibit drifts on the order of tens of ns. We developed a technique to correct for the GPS drifts, and an independentmore » method used for cross-checks that indeed we reach nanosecond-scale timing accuracy by this correction. First, we operate a “beacon transmitter” which emits defined sine waves detected by AERA antennas recorded within the physics data. The relative phasing of these sine waves can be used to correct for GPS clock drifts. In addition to this, we observe radio pulses emitted by commercial airplanes, the position of which we determine in real time from Automatic Dependent Surveillance Broadcasts intercepted with a software-defined radio. From the known source location and the measured arrival times of the pulses we determine relative timing offsets between radio detector stations. We demonstrate with a combined analysis that the two methods give a consistent timing calibration with an accuracy of 2 ns or better. Consequently, the beacon method alone can be used in the future to continuously determine and correct for GPS clock drifts in each individual event measured by AERA.« less

  4. Biomass burning contribution to ambient air particulate levels at Navrongo in the Savannah zone of Ghana.

    PubMed

    Ofosu, Francis G; Hopke, Philip K; Aboh, Innocent J K; Bamford, Samuel A

    2013-09-01

    The concentrations of airborne particulate matter (PM) in Navrongo, a town in the Sahel Savannah Zone of Ghana, have been measured and the major sources have been identified. This area is prone to frequent particulate pollution episodes due to Harmattan dust and biomass burning, mostly from annual bushfires. The contribution of combustion emissions, particularly from biomass and fossil fuel, to ambient air particulate loadings was assessed. Sampling was conducted from February 2009 to February 2010 in Navrongo. Two Gent samplers were equipped to collect PM10 in two size fractions, coarse (PM10-2.5) and fine (PM2.5). Coarse particles are collected on a coated, 8-microm-pore Nuclepore filter. Fine particle samples were sampled with 47-mm-diameter Nuclepore and quartz filters. Elemental carbon (EC) and organic carbon (OC) concentrations were determined from the quartz filters using thermal optical reflectance (IMPROVE/TOR) methods. Elements were measured on the fine-particle Nuclepore filters using energy-dispersive x-ray fluorescence. The average PM2.5 mass concentration obtained at Navrongo was 32.3 microg/m. High carbonaceous concentrations were obtained from November to March, the period of Harmattan dust and severe bush fires. Total carbon was found to contribute approximately 40% of the PM2.5 particulate mass. Positive matrix factorization (PMF) suggested six major sources contributing to the PM2.5 mass. They are two stroke engines, gasoline emissions, soil dust, diesel emissions, biomass burning, and resuspended soil dust. Biomass combustion (16.0%) was identified as second most important source next to soil dust at Navrongo.

  5. Altered Methylation in Tandem Repeat Element and Elemental Component Levels in Inhalable Air Particles

    PubMed Central

    Hou, Lifang; Zhang, Xiao; Zheng, Yinan; Wang, Sheng; Dou, Chang; Guo, Liqiong; Byun, Hyang-Min; Motta, Valeria; McCracken, John; Díaz, Anaité; Kang, Choong-Min; Koutrakis, Petros; Bertazzi, Pier Alberto; Li, Jingyun; Schwartz, Joel; Baccarelli, Andrea A.

    2014-01-01

    Exposure to particulate matter (PM) has been associated with lung cancer risk in epidemiology investigations. Elemental components of PM have been suggested to have critical roles in PM toxicity, but the molecular mechanisms underlying their association with cancer risks remain poorly understood. DNA methylation has emerged as a promising biomarker for environmental-related diseases, including lung cancer. In this study, we evaluated the effects of PM elemental components on methylation of three tandem repeats in a highly-exposed population in Beijing, China. The Beijing Truck Driver Air Pollution Study was conducted shortly before the 2008 Beijing Olympic Games (June 15-July 27, 2008) and included 60 truck drivers and 60 office workers. On two days separated by 1-2 weeks, we measured blood DNA methylation of SATα, NBL2, D4Z4, and personal exposure to eight elemental components in PM2.5, including aluminum (Al), silicon (Si), sulfur (S), potassium (K), calcium (Ca) titanium (Ti), iron (Fe), and zinc (Zn). We estimated the associations of individual elemental component with each tandem repeat methylation in generalized estimating equations (GEE) models adjusted for PM2.5 mass and other covariates. Out of the eight examined elements, NBL2 methylation was positively associated with concentrations of Si (0.121, 95%CI: 0.030; 0.212, FDR=0.047) and Ca (0.065, 95%CI: 0.014; 0.115, FDR=0.047) in truck drivers. In office workers, SATα methylation was positively associated with concentrations of S (0.115, 95%CI: 0.034; 0.196, FDR=0.042). PM-associated differences in blood tandem-repeat methylation may help detect biological effects of the exposure and identify individuals who may eventually experience higher lung cancer risk. PMID:24273195

  6. Nanosecond-level time synchronization of autonomous radio detector stations for extensive air showers

    NASA Astrophysics Data System (ADS)

    The Pierre Auger Collaboration

    2016-01-01

    To exploit the full potential of radio measurements of cosmic-ray air showers at MHz frequencies, a detector timing synchronization within 1 ns is needed. Large distributed radio detector arrays such as the Auger Engineering Radio Array (AERA) rely on timing via the Global Positioning System (GPS) for the synchronization of individual detector station clocks. Unfortunately, GPS timing is expected to have an accuracy no better than about 5 ns. In practice, in particular in AERA, the GPS clocks exhibit drifts on the order of tens of ns. We developed a technique to correct for the GPS drifts, and an independent method is used to cross-check that indeed we reach a nanosecond-scale timing accuracy by this correction. First, we operate a ``beacon transmitter'' which emits defined sine waves detected by AERA antennas recorded within the physics data. The relative phasing of these sine waves can be used to correct for GPS clock drifts. In addition to this, we observe radio pulses emitted by commercial airplanes, the position of which we determine in real time from Automatic Dependent Surveillance Broadcasts intercepted with a software-defined radio. From the known source location and the measured arrival times of the pulses we determine relative timing offsets between radio detector stations. We demonstrate with a combined analysis that the two methods give a consistent timing calibration with an accuracy of 2 ns or better. Consequently, the beacon method alone can be used in the future to continuously determine and correct for GPS clock drifts in each individual event measured by AERA.

  7. An electrical impedance sensor for water level measurements in air-water two-phase stratified flows

    NASA Astrophysics Data System (ADS)

    Ko, Min Seok; Lee, Sung Yong; Lee, Bo An; Yun, Byong Jo; Kim, Kyung Youn; Kim, Sin

    2013-09-01

    We report a design of an optimized ring-type impedance sensor for water level measurements in air-water stratified flows through horizontal pipes. The ring-type sensor is optimized in view of the sensor linearity. In order to determine an optimal electrode and gap size of a ring-type sensor which generates a linear relationship between the impedance (resistance and/or reactance) and the water level, systematic numerical calculations are performed, and a ring-type impedance sensor of electrode width-to-diameter ratio 0.25 and gap-to-diameter ratio 0.2 has been selected as optimal. Lab-scale static experiments have been conducted to verify the sensor performance in terms of the linearity. Finally, this proposed sensor is installed in a horizontal loop 40 mm in diameter and roughly 5200 mm in length and measures water levels for various stratified flow conditions. The comparisons of water level measurements between the proposed sensor and the high-speed camera images post-processed by the edge detection scheme show that the maximum deviation in dimensionless water level is roughly 0.037, which corresponds to 1.5 mm over the range 40 mm.

  8. Absenteeism and respiratory disease among children and adults in Helsinki in relation to low-level air pollution and temperature

    SciTech Connect

    Poenkae, A. )

    1990-06-01

    The weekly changes in ambient sulfur dioxide, nitrogen dioxide, and temperature were compared with the figures for respiratory infection in children and adults and for absenteeism from day-care centers (DCC), schools, and workplaces during a 1-year period in Helsinki. The annual average level of sulfur dioxide was 21 micrograms/m3 and of nitrogen dioxide 47 micrograms/m3; the average temperature was +3.1 degrees C. The levels of these pollutants and the temperature were significantly correlated with the number of upper respiratory infections reported from health centers. Low temperature also correlated with increased frequency of acute tonsillitis, of lower respiratory tract infection among DCC children, and of absenteeism from day-care centers, schools and workplaces. Furthermore, a significant association was found between levels of sulfur dioxide and absenteeism. After statistical standardization for temperature, no other correlations were observed apart from that between high levels of sulfur dioxide and numbers of upper respiratory tract infections diagnosed at health centers (P = 0.04). When the concentrations of sulfur dioxide were above the mean, the frequency of the upper respiratory tract infections was 15% higher than that during the periods of low concentration. The relative importance of the effects of low-level air pollution and low temperature on health is difficult to assess.

  9. Remote detection of air pollution stress to vegetation - Laboratory-level studies

    NASA Technical Reports Server (NTRS)

    Westman, Walter E.; Price, Curtis V.

    1987-01-01

    An experimental investigation of the role of leaf chemistry, anatomy, moisture content, and canopy density on spectral reflectance in healthy and pollution stressed western conifer needles and broad-leafed species of California coastal sage scrub is presented. Acid mist at a level of pH 2.0 is found to more severely effect chlorophyll loss and leaf death than ozone at a level of 0.2 ppm for a four-week period. Both pollutants cause water loss, affecting Bands 4 and 5 in nonlinear ways. The infrared bands initially rise as free water is lost, and subsequently, scattering and reflectance decline. The net effect is shown to be a reduction in TM 4/3 and a rise in TM 5/4 with pollution stress. Under more severe pollution stresses, the decline of leaf area indices due to accelerated leaf drop accentuates the expected TM 4/3 and TM 5/4 changes.

  10. A novel approach to produce road-level inventories of on-road greenhouse gas and air pollutant emissions

    NASA Astrophysics Data System (ADS)

    Powell, J.; Butenhoff, C. L.

    2015-12-01

    Emissions inventories are an important tool often built by governments tomanage and assess greenhouse gases and other air pollutants. High resolutioninventories, both in space and time, are necessary to capture localcharacteristics of on-road transportation emissions in particular. Emissionsvary widely due to the local nature of the fleet, fuel, and roads and thisheterogeneity must inform effective emissions modeling on the urban level. Inaddition, widespread availability of low-cost computing now makes highresolution climate and air quality modeling feasible, but efforts to improveinventories have not kept pace. There currently is a lack of inventories atcomparable resolutions. This motivated similar work such as the VULCAN projectwhich used county-level data to estimate on-road emissions. We are motivatedto improve upon this by using site-level traffic count data where available.Here we show a new high resolution model of CO2 emissions for the Portland,OR metropolitan region. The backbone is an archive of traffic counterrecordings taken by the Portland Bureau of Transportation intermittently at9,352 sites over 21 years and continuing today (1986-2006 data are summarizedhere) and by The Portland Regional Transportation Archive Listing at 309freeway sites. We constructed a regression model to fill in traffic networkgaps using GIS data such as road class and population density. After stepwisetesting of each of eighteen road classes (from minor streets to freeway), wewere able to select ten variables that are significant (P < 0.001) predictorsof traffic; particularly freeway, unimproved road, and minor streets. Themodel was tested by holding back one-third of the data. The R2 for the linearmodel (based on road class and land use) is 0.84. The EPA MOVES model was thenused to estimate transportation CO2 emissions using local fleet, traffic, andmeteorology data.

  11. The influence of electrodialytic remediation on dioxin (PCDD/PCDF) levels in fly ash and air pollution control residues.

    PubMed

    Dias-Ferreira, Celia; Kirkelund, Gunvor M; Jensen, Pernille E

    2016-04-01

    Fly ash and Air Pollution Control (APC) residues collected from three municipal solid waste incinerators in Denmark and Greenland were treated by electrodialytic remediation at pilot scale for 8-10 h. This work presents for the first time the effect of electrodialytic treatment on polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), and how these levels impact on the valorization options for fly ash and APC residue. PCDD/PCDF levels in the original residues ranged between 4.85 and 197 ng g(-1), being higher for the electrostatic precipitator fly ash. The toxic equivalent (TEQ) varied ten fold, ranging 0.18-2.0 ng g(-1) I-TEQ, with penta and hexa-homologs being most significant for toxicity. After the electrodialytic treatment PCDD/PCDF levels increased in the residues (between 1.4 and 2.0 times). This does not mean PCDD/PCDF were synthesized, but else that soluble materials dissolve, leaving behind the non-water soluble compounds, such as PCDD/PCDF. According to the Basel Convention, PCDD/PCDF levels in these materials is low (<15 μg WHO-TEQ kg(-1)) and the fly ash and APC residue could eventually be valorized, for instance as construction material, provided end-of-waste criteria are set and that a risk assessment of individual options is carried out, including the end-of-life stage when the materials become waste again.

  12. [METHODOLOGY FOR THE ASSESSMENT OF THE IMPACT OF THE ATMOSPHERIC AIR POLLUTION ON THE FORMATION OF THE LEVELS OF OVERALL MORBIDITY RATE OF BRONCHIAL ASTHMA].

    PubMed

    Veremchuk, L V; Cherpack, N A; Gvozdenko, T A; Volkova, M V

    2015-01-01

    In large cities with strong air pollution the formation of the levels of morbidity rate of bronchial asthma has a complex causation that requires the search for informative methods for identification of causes and consequences of this dependence. Method for the assessment of the dependence of overall levels of morbidity rate of bronchial asthma on the degree of air pollution allows you to select a "useful information" of the direct impact of air pollution on a background of random processes and latent relationship between human and environment. The use of the method of the information entropy analysis allowed us to estimate the total and the individual contribution of the separate components of air pollution on the formation of levels of total morbidity rate of bronchial asthma in the population of the city of Vladivostok. Levels of total incidence of this pathology were established to differ in various age groups. The adult population is more adapted to air pollution, but retains a high sensitivity to the impact of nitrogen dioxide. Levels of overall l morbidity rate of bronchial asthma in children and adolescents depend on the total air pollution with some dominance of the influence of suspended matter and carbon monoxide.

  13. Air pollution and blood lipid markers levels: Estimating short and long-term effects on elderly hypertension inpatients complicated with or without type 2 diabetes.

    PubMed

    Xiao, Sanhua; Liu, Ranran; Wei, Youxiu; Feng, Lin; Lv, Xuemin; Tang, Fei

    2016-08-01

    With the development of society and the economy, many Chinese cities are shrouded in pollution haze for much of the year. Scientific studies have identified various adverse effects of air pollutants on human beings. However, the relationships between air pollution and blood lipid levels are still unclear. The objective of this study is to explore the short and long-term effects of air pollution on eight blood lipid markers among elderly hypertension inpatients complicated with or without type 2 diabetes (T2D). Blood lipid markers which met the pre-established inclusion criteria were exported from the medical record system. Air pollution data were acquired from the official environmental protection website. Associations between the air quality index and the blood lipid indexes were analyzed by one-way ANOVA and further Bonferroni correction. In an exposure time of 7 days or longer, blood lipid markers were somewhat affected by poor air quality. However, the results could not predict whether atherosclerosis would be promoted or inhibited by poorer air condition. Changes of blood lipid markers of hypertension inpatients with or without T2D were not completely the same, but no blood lipid markers had an opposite trend between the two populations. The air quality index was associated with changes to blood lipid markers to some extent in a population of hypertension inpatients with or without T2D. Further studies are needed to investigate the potential mechanism by which air pollutants induce blood lipids changes.

  14. Levels and spatial distribution of gaseous polychlorinated biphenyls and polychlorinated naphthalenes in the air over the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Qilu; Xu, Yue; Li, Jun; Pan, Xiaohui; Liu, Xiang; Zhang, Gan

    2012-09-01

    Monitoring marine persistent organic pollutants (POPs) is important because oceans play a significant role in the cycling of POPs. The South China Sea (SCS) is surrounded by developing countries in Southeast Asia which are centers of e-waste recycling and the ship dismantling industry. In this study, shipboard air samples collected over the SCS between September 6 and 22, 2005 were analyzed for polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). The levels of ∑12PCBs ranged from 32.3 to 167 pg m-3, with a mean value of 98.4 ± 36.0 pg m-3. Tetra-CBs were the predominant congeners. The concentrations of ∑18PCNs ranged from N.D. to 26.0 pg m-3, with a mean value of 10.5 ± 7.16 pg m-3, and tri-CNs were predominant. The gaseous concentrations of PCBs and PCNs over the SCS were consistent with those over other seas and oceans. Compared with previous studies, it was found that the concentrations of PCBs exhibited an obviously declining trend. The measured PCB and PCN concentrations in the atmosphere over the SCS were influenced by their proximity to source regions and air mass origins. The highest gaseous PCB and PCN concentrations were found at sampling sites adjacent to the continental South China. E-waste recycling, ship dismantling and combustion in South China and some Southeast Asian countries might contribute PCBs and PCNs to the atmosphere of the SCS.

  15. Blood circulation in rat lungs under conditions of reduced oxygen level in inhaled air.

    PubMed

    Ivanov, K P; Mel'nikova, N N

    2012-12-01

    According to some authors, reduction in oxygen level in the lung alveoli results in constriction of afferent vessels, while others observed no vessel constriction. The issue is of principle importance in relation to the lung involvement in body adaptation to hypoxia. Conventional methods are inefficient to solve it, therefore we used a contact microscope allowing observation of lung circulatory system structure and condition of the lung circulatory system in whole, virtually intact animal, on whole undamaged lungs in situ, at normal physiological lung position in the thorax. We found that large vessels carrying blood to the alveoli do not constrict or dilate at reduced Po(2)in lung alveoli. These vessels with a diameter of 15 to 40 μ and more are the only blood source for alveoli.

  16. Within- and Between-Home Variability in Indoor-Air Insecticide Levels during Pregnancy among an Inner-City Cohort from New York City

    PubMed Central

    Whyatt, Robin M.; Garfinkel, Robin; Hoepner, Lori A.; Holmes, Darrell; Borjas, Mejico; Williams, Megan K.; Reyes, Andria; Rauh, Virginia; Perera, Frederica P.; Camann, David E.

    2007-01-01

    Background Residential insecticide use is widespread in the United States, but few data are available on the persistence and variability in levels in the indoor environment. Objective The study aim was to assess within- and between-home variability in indoor-air insecticides over the final 2 months of pregnancy among a cohort of African-American and Dominican women from New York City. Methods Women not employed outside the home were enrolled between February 2001 and May 2004 (n = 102); 9 insecticides and an adjuvant were measured in 48-hr personal air samples and 2-week integrated indoor air samples collected sequentially for 7.0 ± 2.3 weeks (n = 337 air samples). Results Sixty-one percent of the women reported using pest control during the air samplings. Chlorpyrifos, diazinon, and propoxur were detected in 99–100% of personal and indoor samples (range, 0.4–641 ng/m3). Piperonyl butoxide (a pyrethroid adjuvant) was detected in 45.5–68.5% (0.2–608 ng/m3). There was little within-home variability and no significant difference in air concentrations within homes over time (p ≥ 0.2); between-home variability accounted for 88% of the variance in the indoor air levels of propoxur, 92% in chlorpyrifos, 94% in diazinon, and 62% in piperonyl butoxide (p < 0.001). Indoor and maternal personal air insecticide levels were highly correlated (r = 0.7–0.9, p < 0.001). Diazinon and chlorpyrifos levels declined 5-fold between 2001 and 2004 but were detected in all homes 1.5 and 2.5 years, respectively, after the U.S. Environmental Protection Agency ban on their residential use. Conclusion Results showed that the insecticides were persistent in the home with little variability in air concentrations over the 2 months and contributed to chronic maternal inhalation exposures during pregnancy. PMID:17431487

  17. Fungal microcolonies on indoor surfaces — an explanation for the base-level fungal spore counts in indoor air

    NASA Astrophysics Data System (ADS)

    Pasanen, A.-L.; Heinonen-Tanski, H.; Kalliokoski, P.; Jantunen, M. J.

    In the subarctic winter, fungal spores are found in indoor air even when outdoor spore levels are very low. The results of this study support an explanation that some indoor airborne fungal spores are derived from unnoticeable fungal microcolonies, which may develop on temporarily wet surfaces. Laboratory experiments on Penicillium verrucosum indicated that the fungus germinated on new wallpaper very quickly (about half an hour) under moist conditions. Hyphal growth and sporulation of the fungus on moist wallpaper occured within one day of incubation. In gravity-settling tape samples from occasionally wet surfaces in a suburban home, large spore aggregates, hyphal fragments with some spores and spores in the germination stage were found, indicating fungal growth. These experiments showed that fungal microcolonies can develop within a week on occasionally wet indoor surfaces.

  18. Mercury poisoning dentistry: high-level indoor air mercury contamination at selected dental sites.

    PubMed

    Khwaja, Mahmood A; Abbasi, Maryam Shabbir

    2014-01-01

    Mercury (Hg), also known as quick silver, is an essential constituent of dental amalgam. It is a toxic substance of global concern. Children are more at risk from mercury poisoning which affects their neurological development and brain. In the past, a number of studies at dental sites in many countries have been carried out and reported. The present report briefly describes and discusses our recent investigations carried out at 34 dental sites (teaching institutions, hospitals and private clinics) in Pakistan. It is evident from the data that at many sites the indoor mercury vapor levels exceed far above the permissible limit recommended for safe physical and mental health. At these sites, public in general and the medical, paramedical staff and vulnerable population in particular, are at most serious risk to health resulting from exposure to toxic and hazardous mercury. To minimize such risk, some of the recommendations are, best in-house environmental practices for occupational health and safety, mercury contaminated waste reduction at source, mercury specific legislation and ratification of Minamata convention on mercury by Pakistan and other world governments at the earliest time possible.

  19. Highly Integrated Polysulfone/polyacrylonitrile/polyamide-6 Air Filter for Multi-level Physical Sieving Airborne Particles.

    PubMed

    Zhang, Shichao; Tang, Ning; Cao, Leitao; Yin, Xia; Yu, Jianyong; Ding, Bin

    2016-10-04

    Rational structural design involving controlled pore size, high porosity, and particle-targeted function is critical to the realization of highly efficient air filters, and the filter with absolute particle-screen ability has significant technological implications for applications including individual protection, industrial security, and environmental governance; however, it remains an ongoing challenge. In this study, we first report a facile and scalable strategy to fabricate the highly integrated polysulfone/polyacrylonitrile/polyamide-6 (PSU/PAN/PA-6) air filter for multi-level physical sieving airborne particles via sequential electrospinning. Our strategy causes the PSU microfiber (diameter of ~1 μm) layer, PAN nanofiber (diameter of ~200 nm) layer, and PA-6 nanonets (diameter of ~20 nm) layer to orderly assemble into the integrated filter with gradually varied pore structures and high porosity; thus enables the filter to work efficiently by employing different layers to cut off penetration of particles with certain size that exceeds the designed threshold level. By virtue of its elaborate gradient structure, robust hydrophobicity (WCA of ~130o), and superior mechanical property (5.6 MPa), our PSU/PAN/PA-6 filter even can filtrate the 300 nm particles with a high removal efficiency of 99.992% and a low pressure drop of 118 Pa in the way of physical sieving manner, which completely gets rid of the negative impact from high airflow speed, electret failure, and high humidity. It is expected that our highly integrated filter has wider applications for filtration and separation, and design of 3D functional structure in the future.

  20. Nationally representative levels of selected volatile organic compounds in Canadian residential indoor air: population-based survey.

    PubMed

    Zhu, Jiping; Wong, Suzy L; Cakmak, Sabit

    2013-01-01

    A comprehensive, population-based national indoor air survey was conducted in 2009-2011 in Canada. A total of 84 volatile organic carbons (VOCs) from 3218 houses, 546 apartments, and 93 other dwelling types were measured using passive sampling followed by thermal desorption GC/MS. A total of 12 VOCs were measured in both this study and the 1992 Canadian national study. Arithmetic means of VOCs in this study were 2-5 times lower than those in the 1992 study with the exception of a higher styrene level (1.13 μg · m(-3)). Comparing the geometric means of the 24 VOCs showed that levels for the VOCs in this study were comparable to those reported in Europe. They were generally within a factor of 2; 1,4-dichlorobenzene (0.21 μg · m(-3)) and 1,2,4-trimethylbenzene (0.51 μg · m(-3)) were noticeably lower in this study than in the European studies. There were 47 VOCs detected in more than 50% of Canadian households; 33 of them were higher in houses than in apartments for all nonsmoking homes, while only 4 were lower in houses than in apartments. A total of 11 of 47 VOCs were higher in smoking homes compared to nonsmoking homes, while the rest had similar levels. Principal component analysis identified several groups of VOCs with possible common sources.

  1. Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels

    NASA Astrophysics Data System (ADS)

    Som, Sanjoy M.; Buick, Roger; Hagadorn, James W.; Blake, Tim S.; Perreault, John M.; Harnmeijer, Jelte P.; Catling, David C.

    2016-06-01

    How the Earth stayed warm several billion years ago when the Sun was considerably fainter is the long-standing problem of the `faint young Sun paradox'. Because of negligible O2 and only moderate CO2 levels in the Archaean atmosphere, methane has been invoked as an auxiliary greenhouse gas. Alternatively, pressure broadening in a thicker atmosphere with a N2 partial pressure around 1.6-2.4 bar could have enhanced the greenhouse effect. But fossilized raindrop imprints indicate that air pressure 2.7 billion years ago (Gyr) was below twice modern levels and probably below 1.1 bar, precluding such pressure enhancement. This result is supported by nitrogen and argon isotope studies of fluid inclusions in 3.0-3.5 Gyr rocks. Here, we calculate absolute Archaean barometric pressure using the size distribution of gas bubbles in basaltic lava flows that solidified at sea level ~2.7 Gyr in the Pilbara Craton, Australia. Our data indicate a surprisingly low surface atmospheric pressure of Patm = 0.23 +/- 0.23 (2σ) bar, and combined with previous studies suggests ~0.5 bar as an upper limit to late Archaean Patm. The result implies that the thin atmosphere was rich in auxiliary greenhouse gases and that Patm fluctuated over geologic time to a previously unrecognized extent.

  2. [Rationale for the permissible level of carbon dioxide in indoor air in residential and public buildings with the permanent human presence].

    PubMed

    Gubernskiĭ, Iu D

    2014-01-01

    On the base of the analysis of domestic and foreign data on the issue of rating of carbon dioxide in the indoor air of residential and public buildings and results of own research there is justified an permissible level of carbon dioxide in the indoor air of residential and public buildings with a permanent human presence. The concentration of carbon dioxide in the air space, not higher 1000 ppm (0.1%) was established to have no negative impact on the human health and performance, with this content of carbon dioxide there is no accumulation of toxic chemicals and registered by devices reducing of the oxygen content in the air of spaces, it meets the regulatory requirements for content dioxide carbon in the indoor air, applicable in most of foreign countries.

  3. Micronuclei levels in mothers and their newborns from regions with different types of air pollution.

    PubMed

    Rossnerova, Andrea; Spatova, Milada; Pastorkova, Anna; Tabashidze, Nana; Veleminsky, Milos; Balascak, Ivan; Solansky, Ivo; Sram, Radim J

    2011-10-01

    The aim of this study was to analyze genetic damage in human lymphocytes measured using automated image analysis of micronuclei (MN) in a group of 178 mothers and their newborns from two locations in the Czech Republic. The concentrations of benzo[a]pyrene (B[a]P), particulate matter of aerodynamic diameter <2.5 μm (PM2.5) and benzene were measured by stationary monitoring in the winter season of 2008/2009 in the capital city of Prague and in Ceske Budejovice, a regional city in a rural area. The 3-month mean concentration of B[a]P before delivery was lower in Prague in comparison with Ceske Budejovice: 1.9 ± 0.5ng/m³ vs. 3.2 ± 0.2ng/m³ (p<0.001). The opposite trend was found for PM2.5 and benzene: 27.0 ± 2.5μg/m³ and 2.5 ± 0.5μg/m³ vs. 24.5 ± 0.7μg/m³ and 2.1 ± 0.8μg/m³ (p<0.001) for Prague vs. Ceske Budejovice, respectively. The average age of the mothers was 31 years (range, 18-49 years). The frequencies of MN per 1000 binucleated cells were 8.35 ± 3.06 vs. 6.47 ± 2.35 (p<0.001) for mothers from Prague and Ceske Budejovice, respectively, and 2.17 ± 1.32 vs. 3.82 ± 2.43 (p<0.001) for newborns from Prague and Ceske Budejovice, respectively. Other factors, including vitamin intake, exposure to tobacco smoke, body mass index (BMI) before pregnancy, the education level of the mothers and the impact of the mothers' and fathers' ages were analyzed in our study. The results suggest that the different sensitivity of the study groups to various mixtures of carcinogenic pollutants could be affected by significant differences in lifestyle factors. Possible higher genetic damage was analyzed in newborns of smoking mothers, and the birth weight of this group was 7.4% lower (p<0.05) in comparison with the newborns of nonsmoking mothers. No impact of the age of the mothers or fathers on MN frequency in the newborns was observed.

  4. BAERLIN2014 - the influence of land surface types on and the horizontal heterogeneity of air pollutant levels in Berlin

    NASA Astrophysics Data System (ADS)

    Bonn, Boris; von Schneidemesser, Erika; Andrich, Dorota; Quedenau, Jörn; Gerwig, Holger; Lüdecke, Anja; Kura, Jürgen; Pietsch, Axel; Ehlers, Christian; Klemp, Dieter; Kofahl, Claudia; Nothard, Rainer; Kerschbaumer, Andreas; Junkermann, Wolfgang; Grote, Rüdiger; Pohl, Tobias; Weber, Konradin; Lode, Birgit; Schönberger, Philipp; Churkina, Galina; Butler, Tim M.; Lawrence, Mark G.

    2016-06-01

    Urban air quality and human health are among the key aspects of future urban planning. In order to address pollutants such as ozone and particulate matter, efforts need to be made to quantify and reduce their concentrations. One important aspect in understanding urban air quality is the influence of urban vegetation which may act as both emitter and sink for trace gases and aerosol particles. In this context, the "Berlin Air quality and Ecosystem Research: Local and long-range Impact of anthropogenic and Natural hydrocarbons 2014" (BAERLIN2014) campaign was conducted between 2 June and 29 August in the metropolitan area of Berlin and Brandenburg, Germany. The predominant goals of the campaign were (1) the characterization of urban gaseous and particulate pollution and its attribution to anthropogenic and natural sources in the region of interest, especially considering the connection between biogenic volatile organic compounds and particulates and ozone; (2) the quantification of the impact of urban vegetation on organic trace gas levels and the presence of oxidants such as ozone; and (3) to explain the local heterogeneity of pollutants by defining the distribution of sources and sinks relevant for the interpretation of model simulations. In order to do so, the campaign included stationary measurements at urban background station and mobile observations carried out from bicycle, van and airborne platforms. This paper provides an overview of the mobile measurements (Mobile BAERLIN2014) and general conclusions drawn from the analysis. Bicycle measurements showed micro-scale variations of temperature and particulate matter, displaying a substantial reduction of mean temperatures and particulate levels in the proximity of vegetated areas compared to typical urban residential area (background) measurements. Van measurements extended the area covered by bicycle observations and included continuous measurements of O3, NOx, CO, CO2 and point-wise measurement of volatile

  5. Internet Use Patterns, Acceptance Levels. and Policy Recommendations: An Information Technology Infusion Approach to the Internet and the United States Air Force.

    DTIC Science & Technology

    1996-12-01

    well as policy recommendations regarding Internet use in the Air Force. The research provides substantial evidence that Internet technology is not being...highly infused at the headquaners-level than it is at base-level. This research also demonstrates that supervisory support for Internet use positively

  6. Ambient air benzene at background sites in China's most developed coastal regions: exposure levels, source implications and health risks.

    PubMed

    Zhang, Zhou; Wang, Xinming; Zhang, Yanli; Lü, Sujun; Huang, Zhonghui; Huang, Xinyu; Wang, Yuesi

    2015-04-01

    Benzene is a known human carcinogen causing leukemia, yet ambient air quality objectives for benzene are not available in China. The ambient benzene levels at four background sites in China's most developed coastal regions were measured from March 2012 to February 2013. The sites are: SYNECP, in the Northeast China Plain (NECP); YCNCP, in the North China Plain (NCP); THYRD, in the Yangtze River Delta (YRD) and DHPRD, in the Pearl River Delta (PRD). It was found that the mean annual benzene levels (578-1297 ppt) at the background sites were alarmingly higher, especially when compared to those of 60-480 pptv monitored in 28 cities in the United States. Wintertime benzene levels were significantly elevated at both sites (SYNECP and YCNCP) in northern China due to heating with coal/biofuels. Even at these background sites, the lifetime cancer risks of benzene (1.7-3.7E-05) all exceeded 1E-06 set by USEPA as acceptable for adults. At both sites in northern China, good correlations between benzene and CO or chloromethane, together with much lower toluene/benzene (T/B) ratios, suggested that benzene was largely related to coal combustion and biomass/biofuel burning. At the DHPRD site in the PRD, benzene revealed a highly significant correlation with methyl tert-butyl ether (MTBE), indicating that its source was predominantly from vehicle emissions. At the THYRD site in the YRD, higher T/B ratios and correlations between benzene and tetrachloroethylene, or MTBE, implied that benzene levels were probably affected by both traffic-related and industrial emissions.

  7. Investigation of levels in ambient air near sources of Polychlorinated Biphenyls (PCBs) in Kanpur, India, and risk assessment due to inhalation.

    PubMed

    Goel, Anubha; Upadhyay, Kritika; Chakraborty, Mrinmoy

    2016-05-01

    Polychlorinated biphenyls (PCBs) are a class of organic compounds listed as persistent organic pollutant and have been banned for use under Stockholm Convention (1972). They were used primarily in transformers and capacitors, paint, flame retardants, plasticizers, and lubricants. PCBs can be emitted through the primary and secondary sources into the atmosphere, undergo long-range atmospheric transport, and hence have been detected worldwide. Reported levels in ambient air are generally higher in urban areas. Active sampling of ambient air was conducted in Kanpur, a densely populated and industrialized city in the Indo-Gangetic Plain, for detection of 32 priority PCBs, with the aim to determine the concentration in gas/particle phase and assess exposure risk. More than 50 % of PCBs were detected in air. Occurrence in particles was dominated by heavier congeners, and levels in gas phase were below detection. Levels determined in this study are lower than the levels in Coastal areas of India but are at par with other Asian countries where majority of sites chosen for sampling were urban industrial areas. Human health risk estimates through air inhalation pathway were made in terms of lifetime average daily dose (LADD) and incremental lifetime cancer risks (ILCR). The study found lower concentrations of PCBs than guideline values and low health risk estimates through inhalation within acceptable levels, indicating a minimum risk to the adults due to exposure to PCBs present in ambient air in Kanpur.

  8. Prototype development and test results of a continuous ambient air monitoring system for hydrazine at the 10 ppb level

    NASA Astrophysics Data System (ADS)

    Meneghelli, Barry; Parrish, Clyde; Barile, Ron; Lueck, Dale E.

    1995-01-01

    A Hydrazine Vapor Area Monitor (HVAM) system is currently being field tested as a detector for the presence of hydrazine in ambient air. The MDA/Polymetron Hydrazine Analyzer has been incorporated within the HVAM system as the core detector. This analyzer is a three-electrode liquid analyzer typically used in boiler feed water applications. The HVAM system incorporates a dual-phase sample collection/transport method which simultaneously pulls ambient air samples containing hydrazine and a very dilute sulfuric acid solution (0.0001 M) down a length of 1/4 inch outside diameter (OD) tubing from a remote site to the analyzer. The hydrazine-laden dilute acid stream is separated from the air and the pH is adjusted by addition of a dilute caustic solution to a pH greater than 10.2 prior to analysis. Both the dilute acid and caustic used by the HVAM are continuously generated during system operation on an "as needed" basis by mixing a metered amount of concentrated acid/base with dilution water. All of the waste water generated by the analyzer is purified for reuse by Barnstead ion-exchange cartridges so that the entire system minimizes the generation of waste materials. The pumping of all liquid streams and mixing of the caustic solution and dilution water with the incoming sample are done by a single pump motor fitted with the appropriate mix of peristaltic pump heads. The signal to noise (S/N) ratio of the analyzer has been enhanced by adding a stirrer in the MDA liquid cell to provide mixing normally generated by the high liquid flow rate designed by the manufacturer. An onboard microprocessor continuously monitors liquid levels, sample vacuum, and liquid leak sensors, as well as handles communications and other system functions (such as shut down should system malfunctions or errors occur). The overall system response of the HVAM can be automatically checked at regular intervals by measuring the analyzer response to a metered amount of calibration standard injected

  9. Prototype development and test results of a continuous ambient air monitoring system for hydrazine at the 10 ppb level

    NASA Technical Reports Server (NTRS)

    Meneghelli, Barry; Parrish, Clyde; Barile, Ron; Lueck, Dale E.

    1995-01-01

    A Hydrazine Vapor Area Monitor (HVAM) system is currently being field tested as a detector for the presence of hydrazine in ambient air. The MDA/Polymetron Hydrazine Analyzer has been incorporated within the HVAM system as the core detector. This analyzer is a three-electrode liquid analyzer typically used in boiler feed water applications. The HVAM system incorporates a dual-phase sample collection/transport method which simultaneously pulls ambient air samples containing hydrazine and a very dilute sulfuric acid solution (0.0001 M) down a length of 1/4 inch outside diameter (OD) tubing from a remote site to the analyzer. The hydrazine-laden dilute acid stream is separated from the air and the pH is adjusted by addition of a dilute caustic solution to a pH greater than 10.2 prior to analysis. Both the dilute acid and caustic used by the HVAM are continuously generated during system operation on an "as needed" basis by mixing a metered amount of concentrated acid/base with dilution water. All of the waste water generated by the analyzer is purified for reuse by Barnstead ion-exchange cartridges so that the entire system minimizes the generation of waste materials. The pumping of all liquid streams and mixing of the caustic solution and dilution water with the incoming sample are done by a single pump motor fitted with the appropriate mix of peristaltic pump heads. The signal to noise (S/N) ratio of the analyzer has been enhanced by adding a stirrer in the MDA liquid cell to provide mixing normally generated by the high liquid flow rate designed by the manufacturer. An onboard microprocessor continuously monitors liquid levels, sample vacuum, and liquid leak sensors, as well as handles communications and other system functions (such as shut down should system malfunctions or errors occur). The overall system response of the HVAM can be automatically checked at regular intervals by measuring the analyzer response to a metered amount of calibration standard injected

  10. Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level

    NASA Astrophysics Data System (ADS)

    Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

    2016-09-01

    The emission of isoprene and other biogenic volatile organic compounds from vegetation plays an important role in tropospheric ozone (O3) formation. The potentially large expansion of isoprene emitting species (e.g., poplars) for bioenergy production might, therefore, impact tropospheric O3 formation. Using the eddy covariance technique we have simultaneously measured fluxes isoprene, O3 and of CO2 from a poplar (Populus) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground level O3 concentrations. Our findings suggest that isoprene emissions from existing poplar-for-bioenergy plantations do not significantly affect the ground level of O3 concentration. Indeed the overall land in Europe covered with poplar plantations has not significantly changed over the last two decades despite policy incentives to produce bioenergy crops. The current surface area of isoprene emitting poplars-for-bioenergy remains too limited to significantly enhance O3 concentrations and thus to be considered a potential threat for air quality and human health.

  11. Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level

    PubMed Central

    Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

    2016-01-01

    The emission of isoprene and other biogenic volatile organic compounds from vegetation plays an important role in tropospheric ozone (O3) formation. The potentially large expansion of isoprene emitting species (e.g., poplars) for bioenergy production might, therefore, impact tropospheric O3 formation. Using the eddy covariance technique we have simultaneously measured fluxes isoprene, O3 and of CO2 from a poplar (Populus) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground level O3 concentrations. Our findings suggest that isoprene emissions from existing poplar-for-bioenergy plantations do not significantly affect the ground level of O3 concentration. Indeed the overall land in Europe covered with poplar plantations has not significantly changed over the last two decades despite policy incentives to produce bioenergy crops. The current surface area of isoprene emitting poplars-for-bioenergy remains too limited to significantly enhance O3 concentrations and thus to be considered a potential threat for air quality and human health. PMID:27615148

  12. Boundary-Layer Development and Low-level Baroclinicity during High-Latitude Cold-Air Outbreaks: A Simple Model

    NASA Astrophysics Data System (ADS)

    Chechin, Dmitry G.; Lüpkes, Christof

    2017-01-01

    A new quasi-analytical mixed-layer model is formulated describing the evolution of the convective atmospheric boundary layer (ABL) during cold-air outbreaks (CAO) over polar oceans downstream of the marginal sea-ice zones. The new model is superior to previous ones since it predicts not only temperature and mixed-layer height but also the height-averaged horizontal wind components. Results of the mixed-layer model are compared with dropsonde and aircraft observations carried out during several CAOs over the Fram Strait and also with results of a 3D non-hydrostatic (NH3D) model. It is shown that the mixed-layer model reproduces well the observed ABL height, temperature, low-level baroclinicity and its influence on the ABL wind speed. The mixed-layer model underestimates the observed ABL temperature only by about 10 %, most likely due to the neglect of condensation and subsidence. The comparison of the mixed-layer and NH3D model results shows good agreement with respect to wind speed including the formation of wind-speed maxima close to the ice edge. It is concluded that baroclinicity within the ABL governs the structure of the wind field while the baroclinicity above the ABL is important in reproducing the wind speed. It is shown that the baroclinicity in the ABL is strongest close to the ice edge and slowly decays further downwind. Analytical solutions demonstrate that the e-folding distance of this decay is the same as for the decay of the difference between the surface temperature of open water and of the mixed-layer temperature. This distance characterizing cold-air mass transformation ranges from 450 to 850 km for high-latitude CAOs.

  13. Community air monitoring for pesticides. Part 3: using health-based screening levels to evaluate results collected for a year.

    PubMed

    Wofford, Pamela; Segawa, Randy; Schreider, Jay; Federighi, Veda; Neal, Rosemary; Brattesani, Madeline

    2014-03-01

    The CA Department of Pesticide Regulation (CDPR) and the CA Air Resources Board monitored 40 pesticides, including five degradation products, in Parlier, CA, to determine if its residents were exposed to any of these pesticides and, if so, in what amounts. They included 1,3-dichloropropene, acrolein, arsenic, azinphos-methyl, carbon disulfide, chlorpyrifos and its degradation product, chlorthalonil, copper, cypermethrin, diazinon and its degradation product, dichlorvos, dicofol, dimethoate and its degradation product, diuron, endosulfan and its degradation product, S-ethyl dipropylcarbamothioate (EPTC), formaldehyde, malathion and its degradation product, methyl isothiocyanate (MITC), methyl bromide, metolachlor, molinate, norflurazon, oryzalin, oxyfluorfen, permethrin, phosmet, propanil, propargite, simazine, SSS-tributylphosphorotrithioate, sulfur, thiobencarb, trifluralin, and xylene. Monitoring was conducted 3 days per week for a year. Twenty-three pesticides and degradation products were detected. Acrolein, arsenic, carbon disulfide, chlorpyrifos, copper, formaldehyde, methyl bromide, MITC, and sulfur were detected in more than half the samples. Since no regulatory ambient air standards exist for these pesticides, CDPR developed advisory, health-based non-cancer screening levels (SLs) to assess acute, subchronic, and chronic exposures. For carcinogenic pesticides, CDPR assessed risk using cancer potency values. Amongst non-carcinogenic agricultural use pesticides, only diazinon exceeded its SL. For carcinogens, 1,3-dichloropropene concentrations exceeded its cancer potency value. Based on these findings, CDPR has undertaken a more comprehensive evaluation of 1,3-dichloropropene, diazinon, and the closely related chlorpyrifos that was frequently detected. Four chemicals-acrolein, arsenic, carbon disulfide, and formaldehyde-sometimes used as pesticides were detected, although no pesticidal use was reported in the area during this study. Their presence was most

  14. Generalized water-level contours, September-October 2000 and March-April 2001, and long-term water-level changes, at the U.S. Air Force Plant 42 and vicinity, Palmdale, California

    USGS Publications Warehouse

    Christensen, Allen H.

    2005-01-01

    Historically, the U.S. Air Force Plant 42 has relied on ground water as the primary source of water owing, in large part, to the scarcity of surface water in the region. Groundwater withdrawal for municipal, industrial, and agricultural use has affected ground-water levels at U.S. Air Force Plant 42, and vicinity. A study to document changes in groundwater gradients and to present historical water-level data was completed by the U.S. Geological Survey in cooperation with the U.S. Air Force. This report presents historical water-level data, hydrographs, and generalized seasonal water-level and water-level contours for September?October 2000 and March?April 2001. The collection and interpretation of ground-water data helps local water districts, military bases, and private citizens gain a better understanding of the ground-water flow systems, and consequently water availability. During September?October 2000 and March?April 2001 the U.S. Geological Survey and other agencies made a total of 102 water-level measurements, 46 during September?October 2000 and 56 during March?April 2001. These data document recent conditions and, when compared with historical data, document changes in ground-water levels. Two water-level contour maps were drawn: the first depicts water-level conditions for September?October 2000 map and the second depicts water-level conditions for March?April 2001 map. In general, the water-level contour maps show water-level depressions formed as result of ground-water withdrawal. One hundred sixteen long-term hydrographs, using water-level data from 1915 through 2000, were constructed to show water-level trends in the area. The hydrographs indicate that water-level decline occurred throughout the study area, with the greatest declines south of U.S. Air Force Plant 42.

  15. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    NASA Astrophysics Data System (ADS)

    Ibrayev, R. A.; Özsoy, E.; Schrum, C.; Sur, H. I.

    2010-03-01

    A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December-January; Eckman south-, south-westward drift in February-July embedded by western and eastern southward coastal currents and transition type in August-November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  16. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    NASA Astrophysics Data System (ADS)

    Ibrayev, R. A.; Özsoy, E.; Schrum, C.; Sur, H. İ.

    2009-09-01

    A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December-January; Eckman south-, south-westward drift in February-July embedded by western and eastern southward coastal currents and transition type in August-November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. Model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  17. 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

  18. SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

    SciTech Connect

    Jiang, H; Lee, Y; Pokhrel, D; Badkul, R

    2015-06-15

    Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators.

  19. An Evaluation of the Implied Shortage Factor and Its Effect on the Air Force Logistics Command’s Economic Order Quantity (EOQ) Variable Safety Level.

    DTIC Science & Technology

    Order Quantity (EOQ) model and a derivation of the Presutti and Trepp Model IV to establish inventory variable safety levels. The safety level (SL...implied shortage factor, lambda is an arbitrary value that has a major effect on the SL formula and inventory levels at each wholesale supply depot, the...Air Logistics Center. The objective of this thesis was to determine the effectiveness of the process by which lambda has been previously determined at

  20. Contactless electroreflectance studies of the Fermi level position at the air/GaN interface: Bistable nature of the Ga-polar surface

    NASA Astrophysics Data System (ADS)

    Janicki, Łukasz; Gładysiewicz, Marta; Misiewicz, Jan; Klosek, Kamil; Sobanska, Marta; Kempisty, Paweł; Zytkiewicz, Zbigniew R.; Kudrawiec, Robert

    2017-02-01

    In this paper we show that the surface Fermi level of Ga-polar GaN exhibits a bistable behavior allowing it to be located at two distinct energetic positions at the air/GaN interface which is unusual for other III-V semiconductors such as GaAs or GaSb. To determine the Fermi level position at the air/GaN interface we perform contactless electroreflectance measurements on specially designed UD+ structures [GaN(undoped)/GaN(highly doped)/substrate] doped by Si and Mg. Analyzing the period of Franz-Keldysh oscillation we determine the built-in electric field in the undoped (U) layer. These studies coupled with numerical solutions of the Poisson equation allowed us to determine the position of the Fermi level at the air/GaN interface. We observe a change in the band bending correlated to different Fermi level positions in the doped (D+) layer. We show that depending on the doping type in the D+ layer the Fermi level at the air/GaN interface is located in the upper or lower singularity of surface density of states (SDOS) for Si or Mg doping of D+ layer, respectively. We support our findings with the density functional theory calculations of the SDOS and the dependence of the Fermi level position on the doping concentration in the bulk of a GaN slab.

  1. Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers.

    PubMed

    Estellano, Victor H; Pozo, Karla; Efstathiou, Christos; Pozo, Katerine; Corsolini, Simonetta; Focardi, Silvano

    2015-10-01

    Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3-5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC-MS. The organophosphates insecticides; chlorpyrifos (3-580 pg m(-3)) and chlorpyrifos-methyl (below detection limit - to 570 pg m(-3)) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk.

  2. Prevalence rates of respiratory symptoms in Italian general population samples exposed to different levels of air pollution

    SciTech Connect

    Viegi, G. Univ. of Arizona, Tucson ); Paoletti, P.; Carrozzi, L.; Vellutini, M.; Diviggiano, E.; Pistelli, G.; Giutini, G. ); Di Pede, C. Occupational Medicine Service, Toscana ); Lebowitz, M.D. )

    1991-08-01

    The authors surveyed two general population samples aged 8 to 64 living in the unpolluted, rural area of the Po Delta (northern Italy) and in the urban area of Pisa (central Italy). Each subject filled out a standardized interviewer-administered questionnaire. The Pisa sample was divided into three groups according to their residence in the urban-suburban areas and to outdoor air pollution exposure (automobile exhaust only or industrial fumes as well). Significantly higher prevalence rates of all the respiratory symptoms and diseases were found in Pisa compared with the Po Delta. Current smoking was more frequent in the rural area, but the urban smokers had a higher lifetime cigarette consumption. Childhood respiratory trouble and recurrent respiratory illnesses were evenly distributed. Exposure to parental smoking in childhood and lower educational level were more frequent in Po Delta, whereas familial history of respiratory/allergic disorders and work and indoor exposures were more often reported in the city. Multiple logistic regression models estimating independently the role of the various risk factors showed significant odds ratios associated with residence in Pisa for all the symptoms but chronic phlegm. The conclusion, these preliminary analyses indicate an urban factor related to the rates of respiratory symptoms and diseases in Italy in the 1980s.

  3. Lead exposure in starter battery production: investigation of the correlation between air lead and blood lead levels.

    PubMed

    Kentner, M; Fischer, T

    1994-01-01

    The threshold limit value (TLV) for lead (in Germany, the MAK value) is based on a certain blood lead concentration (in Germany BAT value = biological tolerance value for working materials) that is not to be exceeded; thereby a statistically significant association between air lead (PbA) and blood lead (PbB) is assumed. On the basis of a 10-year period of (1982-1991) biological and ambient monitoring of 134 battery factory staff and their workplaces, a PbA/PbB correlation with the regression equation PbB = 62.183 + 21.242 x Log 10 (PbA) (n = 1089, r = 0.274, P < 0.001) was calculated. These results are in line with those of several other investigations. The shape of the regression curve and the wide scattering of values led to the assumption that PbA values above the MAK value (0.1 mg/m3) do not necessarily result in increased PbB values. Similarly, PbA values lower than the MAK value do not guarantee PbB levels below the BAT value in every case. These observations are influenced by numerous confounders and intervening variables. It is concluded that lowering MAK values as a consequence of lowering BAT values is not mandatory.

  4. Prevalence of respiratory conditions among schoolchildren exposed to different levels of air pollutants in the Haifa Bay area, Israel.

    PubMed Central

    Goren, A I; Hellman, S; Brenner, S; Egoz, N; Rishpon, S

    1990-01-01

    During spring 1984, 2334 second and 2000 fifth-grade schoolchildren living in three Haifa Bay areas on the eastern Mediterranean coast with different levels of air pollution were studied. The parents of these children filled out American Thoracic Society and National Heart and Lung Institute health questionnaires, and the children performed the following pulmonary function tests (PFT); FVC, FEV1, FEV1/FEV, PEF, FEF50, and FEF75. A trend of higher prevalence of most reported respiratory symptoms was found for schoolchildren growing up in the medium and high pollution areas as compared with the low pollution area. Part of the reported respiratory diseases were significantly more common among children from the high pollution area. Models fitted for the respiratory conditions that differed significantly among the three areas of residence also included background variables that could be responsible for these differences. Relative risk values, which were calculated from the logistic models, were in the range of 1.38 for sputum with cold and 1.81 for sputum without cold for children from the high pollution area as compared with 1.00 for children from the low pollution area. All the measured values of PFT were within the normal range. There was no consistent trend of reduced pulmonary function that characterized any residential area. PMID:2088751

  5. [Air quality in schools - classroom levels of carbon dioxide (CO2), volatile organic compounds (VOC), aldehydes, endotoxins and cat allergen].

    PubMed

    Fromme, H; Heitmann, D; Dietrich, S; Schierl, R; Körner, W; Kiranoglu, M; Zapf, A; Twardella, D

    2008-02-01

    Children are assumed to be more vulnerable to health hazards and spend a large part of their time in schools. To assess the exposure situation in this microenvironment, we evaluated the indoor air quality in winter 2004/5 in 92 classrooms, and in 75 classrooms in summer 2005 in south Bavaria, Germany. Indoor air climate parameters (temperature, relative humidity), carbon dioxide (CO2) and various volatile organic compounds, aldehydes and ketones were measured. Additionally, cat allergen (Fel d1) and endotoxin (LAL-test) were analysed in the settled dust of school rooms. Data on room and building characteristics were collected by use of a standardised form. Only data collected during teaching hours were considered in analysis. The median indoor CO2 concentration in the classrooms ranged in the winter and summer period from 598 to 4 172 ppm and 480 to 1 875 ppm, respectively. While during the winter period in 92% of the classrooms the CO2 daily medians went above 1 000 ppm, the percentage of classrooms with increased CO2 concentration fell to 28% in summer. In winter, in 60% of classes the daily median CO2 concentration exceeded 1 500 ppm, while in summer this threshold was reached by only 9%. A high concentration of CO2 was associated with a high number of pupils, a low room surface area and a low room volume. The levels of total volatile organic compounds (TVOC) in classrooms ranged between 110 and 1 000 microg/m3 (median in winter 345 microg/m3, in summer 260 microg/m3). Acetone, formaldehyde and acetaldehyde were measured in concentrations from 14.0 to 911 microg/m3, from 3.1 to 46.1 microg/m3, and from 2.9 to 78 microg/m3, respectively. The other aldehydes were detected in minor amounts only. The median Fel d1 level in winter was 485 ng/g dust (20 to 45 160 ng/g) and in summer it was 417 ng/g (40-7 470 ng/g). We observed no marked differences between the two sampling periods and between smooth floors and rooms with carpeted floors. No differences were found

  6. Trends of road dust emissions contributions on ambient air particulate levels at rural, urban and industrial sites in southern Spain

    NASA Astrophysics Data System (ADS)

    Amato, F.; Alastuey, A.; de la Rosa, J.; Sánchez de la Campa, A. M.; Pandolfi, M.; Lozano, A.; Contreras González, J.; Querol, X.

    2014-04-01

    The impact of road dust emissions on PM10 and PM2.5 (atmospheric particulate matter with diameteer < 10 μm and 2.5 μm mass concentrations recorded from 2003 to 2010 at 11 locations (rural, urban and industrial) in southern Spain was estimated based on the chemical characterization of PM and the use of a constrained Positive Matrix Factorization, where the chemical profile of local road dust samples is used as a priori knowledge. Results indicate that road dust increased PM10 levels on average by 21-35% at traffic sites, 29-34% at urban background sites heavily affected by road traffic emissions, 17-22% at urban-industrial sites and 9-22% at rural sites. Road dust contributions to ambient PM levels show a marked seasonality with maxima in summer and minima in winter, likely due to the rainfall frequency. Decreasing concentration trends over the sampling years were found at some traffic and urban sites but in most cases the decreases were less significant than for vehicle exhaust emissions, while concentrations increased at industrial sites, probably due to local peculiarities. Concerning PM2.5, road dust contributions were lower than in PM10, as expected but still important (21-31%, 11-31%, 6-16% and 7% for traffic, urban background, urban-industrial and rural sites, respectively). In addition the three main sources of road dust (carbonaceous particles, brake wear and road wear/mineral) were identified and their contributions to road dust mass loadings estimated, supporting the idea that air quality managers should drive measures aimed at preventing the build-up of road dust particles on roads.

  7. 24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HOME CONSTRUCTION AND SAFETY STANDARDS Testing § 3280.406 Air chamber test method for certification and... wrapped until preconditioning is initiated. (2) Panels selected for testing in the air chamber shall not be taken from the top or bottom of the stack. (b) Testing. Testing must be conducted in...

  8. 24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HOME CONSTRUCTION AND SAFETY STANDARDS Testing § 3280.406 Air chamber test method for certification and... wrapped until preconditioning is initiated. (2) Panels selected for testing in the air chamber shall not be taken from the top or bottom of the stack. (b) Testing. Testing must be conducted in...

  9. 24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HOME CONSTRUCTION AND SAFETY STANDARDS Testing § 3280.406 Air chamber test method for certification and... wrapped until preconditioning is initiated. (2) Panels selected for testing in the air chamber shall not be taken from the top or bottom of the stack. (b) Testing. Testing must be conducted in...

  10. Estimation of exposure to atmospheric pollutants during pregnancy integrating space-time activity and indoor air levels: Does it make a difference?

    PubMed

    Ouidir, Marion; Giorgis-Allemand, Lise; Lyon-Caen, Sarah; Morelli, Xavier; Cracowski, Claire; Pontet, Sabrina; Pin, Isabelle; Lepeule, Johanna; Siroux, Valérie; Slama, Rémy

    2015-11-01

    Studies of air pollution effects during pregnancy generally only consider exposure in the outdoor air at the home address. We aimed to compare exposure models differing in their ability to account for the spatial resolution of pollutants, space-time activity and indoor air pollution levels. We recruited 40 pregnant women in the Grenoble urban area, France, who carried a Global Positioning System (GPS) during up to 3 weeks; in a subgroup, indoor measurements of fine particles (PM2.5) were conducted at home (n=9) and personal exposure to nitrogen dioxide (NO2) was assessed using passive air samplers (n=10). Outdoor concentrations of NO2, and PM2.5 were estimated from a dispersion model with a fine spatial resolution. Women spent on average 16 h per day at home. Considering only outdoor levels, for estimates at the home address, the correlation between the estimate using the nearest background air monitoring station and the estimate from the dispersion model was high (r=0.93) for PM2.5 and moderate (r=0.67) for NO2. The model incorporating clean GPS data was less correlated with the estimate relying on raw GPS data (r=0.77) than the model ignoring space-time activity (r=0.93). PM2.5 outdoor levels were not to moderately correlated with estimates from the model incorporating indoor measurements and space-time activity (r=-0.10 to 0.47), while NO2 personal levels were not correlated with outdoor levels (r=-0.42 to 0.03). In this urban area, accounting for space-time activity little influenced exposure estimates; in a subgroup of subjects (n=9), incorporating indoor pollution levels seemed to strongly modify them.

  11. Estimation of exposure to atmospheric pollutants during pregnancy integrating space-time activity and indoor air levels: does it make a difference?

    PubMed Central

    Marion, OUIDIR; Lise, GIORGIS-ALLEMAND; Sarah, LYON-CAEN; Xavier, MORELLI; Claire, CRACOWSKI; Sabrina, PONTET; Isabelle, PIN; Johanna, LEPEULE; Valérie, SIROUX; Rémy, SLAMA

    2016-01-01

    Studies of air pollution effects during pregnancy generally only consider exposure in the outdoor air at the home address. We aimed to compare exposure models differing in their ability to account for the spatial resolution of pollutants, space-time activity and indoor air pollution levels. We recruited 40 pregnant women in the Grenoble urban area, France, who carried a Global Positioning System (GPS) during up to 3 weeks; in a subgroup, indoor measurements of fine particles (PM2.5) were conducted at home (n=9) and personal exposure to nitrogen dioxide (NO2) was assessed using passive air samplers (n=10). Outdoor concentrations of NO2, and PM2.5 were estimated from a dispersion model with a fine spatial resolution. Women spent on average 16 h per day at home. Considering only outdoor levels, for estimates at the home address, the correlation between the estimate using the nearest background air monitoring station and the estimate from the dispersion model was high (r=0.93) for PM2.5 and moderate (r=0.67) for NO2. The model incorporating clean GPS data was less correlated with the estimate relying on raw GPS data (r=0.77) than the model ignoring space-time activity (r=0.93). PM2.5 outdoor levels were not to moderately correlated with estimates from the model incorporating indoor measurements and space-time activity (r=−0.10 to 0.47), while NO2 personal levels were not correlated with outdoor levels (r=−0.42 to 0.03). In this urban area, accounting for space-time activity little influenced exposure estimates; in a subgroup of subjects (n=9), incorporating indoor pollution levels seemed to strongly modify them. PMID:26300245

  12. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

    PubMed

    Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-02-01

    This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications.

  13. Leveling

    USGS Publications Warehouse

    1966-01-01

    Geodetic leveling by the U.S. Geological Survey provides a framework of accurate elevations for topographic mapping. Elevations are referred to the Sea Level Datum of 1929. Lines of leveling may be run either with automatic or with precise spirit levels, by either the center-wire or the three-wire method. For future use, the surveys are monumented with bench marks, using standard metal tablets or other marking devices. The elevations are adjusted by least squares or other suitable method and are published in lists of control.

  14. The south Karelia air pollution study: Effects of low-level expsoure to malodorous sulfur compounds on symptoms

    SciTech Connect

    Partti-Pellinen, K.; Marttila, O.; Vilkka, V.; Jaakkola, J.J. |

    1996-07-01

    Exposure to very low levels of ambient-air malodorous sulfur compounds and their effect on eye irritation, respiratory-tract symptoms, and central nervous system symptoms in adults were assessed. A cross-sectional self-administered questionnaire (response rate = 77%) was distributed during March and April 1992 to adults (n = 336) who lived in a neighborhood that contained a pulp mill and in a nonpolluted reference community (n = 380). In the exposed community, the measured annual mean concentrations of total reduced sulfur compounds and sulfur dioxide measured in two stations were 2 to 3 {mu}g/m{sup 3} and 1 {mu}g/m{sup 3}, respectively. In the reference community, the annual mean concentration of sulfur dioxide was 1 {mu}g/m{sup 3}. The residents of the community near the pulp mill reported an excess of cough, respiratory infections, and headache during the previous 4 wk, as well as during the preceding 12 mo. The relative risk for headache was increased significantly in the exposed community, compared with the reference area: the adjusted odds ratio (aOR) was 1.83 (95% confidence interval [95% Cl] = 1.06-3.15) during the previous 4 wk and 1.70 (95% Cl = 1.05-2.73) during the preceding 12 mo. The relative risk for cough was also increased during the preceding 12 mo (aOR = 1.64, 95% Cl = 1.01-2.64). These results indicated that adverse health effects of malodorous sulfur compounds occur at lower concentrations than reported previously. 25 refs., 3 tabs.

  15. An in situ-based analysis of the relationship between land surface "skin" and screen-level air temperatures

    NASA Astrophysics Data System (ADS)

    Good, Elizabeth Jane

    2016-08-01

    This paper presents an analysis of the relationship between land surface temperatures (LST) and screen-level air temperatures (T2m) using in situ observations from 19 Atmospheric Radiation Measurement (ARM) deployments located in a range of geographical regimes. The diurnal cycle is resolved using 1 min observations: a particular focus of the study is on the relationship between daily extremes of LST (LSTmax, LSTmin) and T2m (Tmax, Tmin). Temperature differences are analyzed with respect to cloud, wind speed, and snow cover. Under cloud-free, low wind speed conditions, daytime LST is often several degrees Celsius (°C) higher than T2m at low-to-middle latitudes and at high latitudes during the summer months. In contrast, LST and T2m are often close (e.g., within 2°C) under cloudy and/or moderate-to-high wind speed conditions or when solar insolation is low or absent. LSTmin and Tmin are generally well correlated (r > 0.8, often r > 0.9), while seasonal correlations between LSTmax and Tmax are weaker (r > 0.6, often r > 0.8). At high latitudes, LST and T2m are well coupled in spring/autumn/winter; the relationship between LST and T2m tends to weaken with decreasing latitude. The timing of daily extremes is also investigated and it is found that LSTmin and Tmin typically occur close to sunrise, with Tmin occurring slightly after LSTmin. LSTmax occurs close to solar noon, with Tmax typically occurring 1-3 hours later. This study will inform temperature data users on differences between LST and T2m and aid development of methods to estimate T2m using satellite LSTs.

  16. Pollution level, phase distribution and health risk of polycyclic aromatic hydrocarbons in indoor air at public places of Hangzhou, China.

    PubMed

    Lu, Hao; Zhu, Lizhong; Chen, Shuguang

    2008-04-01

    PAHs pollution survey in air of public places was conducted in Hangzhou, China. The most serious PAHs pollution was observed in indoor air of shopping centers and the slightest was in train stations. The molecular weight of chrysene (MW 228) appeared to be the dividing line for the PAHs with a larger or smaller distribution in the vapor or particulate phase. Concentrations of 15 PAHs on PM2.5 accounted for 71.3% of total particulate PAHs, and followed by PM2.5-10 fraction (17.6%) and >PM10 fraction (11.1%). In shopping centers and supermarkets, emission of 2-4 rings PAHs occurred from indoor sources, whereas 5-6 rings PAHs predominantly originated from transport of outdoor air. In temples, PAHs in indoor air mainly originated from incense burning. Health risks associated with the inhalation of PAHs were assessed, and naphthalene made the greatest contribution (62.4%) to the total health risks.

  17. Field controlled experiments on the physiological responses of maize (Zea mays L.) leaves to low-level air and soil mercury exposures.

    PubMed

    Niu, Zhenchuan; Zhang, Xiaoshan; Wang, Sen; Zeng, Ming; Wang, Zhangwei; Zhang, Yi; Ci, Zhijia

    2014-01-01

    Thousands of tons of mercury (Hg) are released from anthropogenic and natural sources to the atmosphere in a gaseous elemental form per year, yet little is known regarding the influence of airborne Hg on the physiological activities of plant leaves. In the present study, the effects of low-level air and soil Hg exposures on the gas exchange parameters of maize (Zea mays L.) leaves and their accumulation of Hg, proline, and malondialdehyde (MDA) were examined via field open-top chamber and Hg-enriched soil experiments, respectively. Low-level air Hg exposures (<50 ng m(-3)) had little effects on the gas exchange parameters of maize leaves during most of the daytime (p > 0.05). However, both the net photosynthesis rate and carboxylation efficiency of maize leaves exposed to 50 ng m(-3) air Hg were significantly lower than those exposed to 2 ng m(-3) air Hg in late morning (p < 0.05). Additionally, the Hg, proline, and MDA concentrations in maize leaves exposed to 20 and 50 ng m(-3) air Hg were significantly higher than those exposed to 2 ng m(-3) air Hg (p < 0.05). These results indicated that the increase in airborne Hg potentially damaged functional photosynthetic apparatus in plant leaves, inducing free proline accumulation and membrane lipid peroxidation. Due to minor translocation of soil Hg to the leaves, low-level soil Hg exposures (<1,000 ng g(-1)) had no significant influences on the gas exchange parameters, or the Hg, proline, and MDA concentrations in maize leaves (p > 0.05). Compared to soil Hg, airborne Hg easily caused physiological stress to plant leaves. The effects of increasing atmospheric Hg concentration on plant physiology should be of concern.

  18. Materials, processes, and characterization of extended air-gaps for the intra-level interconnection of integrated circuits

    NASA Astrophysics Data System (ADS)

    Park, Seongho

    The integration of an air-gap as an ultra low dielectric constant material in an infra-metal dielectric region of interconnect structure in integrated circuits was investigated in terms of material properties of a thermally decomposable sacrificial polymer, fabrication processes and electrical performance. Extension of the air-gap into the inter-layer dielectric region reduces the interconnect capacitance. In order to enhance the hardness of a polymer for the better process reliabilities, a conventional norbornene-based sacrificial polymer was electron-beam irradiated. Although the hardness of the polymer increased, the thermal properties degraded. A new high modulus tetracyclododecene-based sacrificial polymer was characterized and compared to the norbornene-based polymer in terms of hardness, process reliability and thermal properties. The tetracyclododecene-based polymer was harder and showed better process reliability than the norbomene-based sacrificial polymer. Using the tetracyclododecene-based sacrificial polymer, a single layer Cu/air-gap and extended Culair-gap structures were fabricated. The effective dielectric constant of the air-gap and extended air-gap structures were 2.42 and 2.17, respectively. This meets the requirements for the 32 nm node. Moisture uptake of the extended Cu/air-gap structure increased the effective dielectric constant. The exposure of the structure to hexamethyldisilazane vapor removed the absorbed moisture and changed the structure hydrophobic, improving the integration reliability. The integration processes of the air-gap and the extended air-gap into a dual damascene Cu metallization process has been proposed and compared to state-of-the-art integration approaches.

  19. In pursuit of clean air: a data book of problems and strategies at the state level. Supplement

    SciTech Connect

    Garvey, D.B.; Moser, S.B.; Streets, D.G.

    1980-08-01

    The Clean Air Act Amendments of 1977 and EPA regulations set stringent requirements for the control of emissions in areas where the National Ambient Air Quality Standards were being exceeded. This supplement updates a previous five-volume summary of nonattainment area designations and attainment strategies of the states as of July 1, 1980. It also contains maps of PSD Class I areas and additional information on coal production, coal reserves, and coal quality.

  20. Conception and realization of a parallel-plate free-air ionization chamber for the absolute dosimetry of an ultrasoft X-ray beam

    NASA Astrophysics Data System (ADS)

    Groetz, J.-E.; Ounoughi, N.; Mavon, C.; Belafrites, A.; Fromm, M.

    2014-08-01

    We report the design of a millimeter-sized parallel plate free-air ionization chamber (IC) aimed at determining the absolute air kerma rate of an ultra-soft X-ray beam (E = 1.5 keV). The size of the IC was determined so that the measurement volume satisfies the condition of charged-particle equilibrium. The correction factors necessary to properly measure the absolute kerma using the IC have been established. Particular attention was given to the determination of the effective mean energy for the 1.5 keV photons using the PENELOPE code. Other correction factors were determined by means of computer simulation (COMSOL™and FLUKA). Measurements of air kerma rates under specific operating parameters of the lab-bench X-ray source have been performed at various distances from that source and compared to Monte Carlo calculations. We show that the developed ionization chamber makes it possible to determine accurate photon fluence rates in routine work and will constitute substantial time-savings for future radiobiological experiments based on the use of ultra-soft X-rays.

  1. Conception and realization of a parallel-plate free-air ionization chamber for the absolute dosimetry of an ultrasoft X-ray beam

    SciTech Connect

    Groetz, J.-E. Mavon, C.; Fromm, M.; Ounoughi, N.; Belafrites, A.

    2014-08-15

    We report the design of a millimeter-sized parallel plate free-air ionization chamber (IC) aimed at determining the absolute air kerma rate of an ultra-soft X-ray beam (E = 1.5 keV). The size of the IC was determined so that the measurement volume satisfies the condition of charged-particle equilibrium. The correction factors necessary to properly measure the absolute kerma using the IC have been established. Particular attention was given to the determination of the effective mean energy for the 1.5 keV photons using the PENELOPE code. Other correction factors were determined by means of computer simulation (COMSOL™and FLUKA). Measurements of air kerma rates under specific operating parameters of the lab-bench X-ray source have been performed at various distances from that source and compared to Monte Carlo calculations. We show that the developed ionization chamber makes it possible to determine accurate photon fluence rates in routine work and will constitute substantial time-savings for future radiobiological experiments based on the use of ultra-soft X-rays.

  2. Outdoor air pollution, subtypes and severity of ischemic stroke – a small-area level ecological study

    PubMed Central

    2014-01-01

    Background Evidence linking outdoor air pollution and incidence of ischemic stroke subtypes and severity is limited. We examined associations between outdoor PM10 and NO2 concentrations modeled at a fine spatial resolution and etiological and clinical ischemic stroke subtypes and severity of ischemic stroke. Methods We used a small-area level ecological study design and a stroke register set up to capture all incident cases of first ever stroke (1995–2007) occurring in a defined geographical area in South London (948 census output areas; population of 267839). Modeled PM10 and NO2 concentrations were available at a very fine spatial scale (20 meter by 20 meter grid point resolution) and were aggregated to output area level using postcode population weighted averages. Ischemic stroke was classified using the Oxford clinical classification, the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiological classification, National Institutes of Health Stroke Scale (NIHSS) score and a pragmatic clinical severity classification based on Glasgow coma score, ability to swallow, urinary continence and death <2 days of stroke onset. Results Mean (SD) concentrations were 25.1 (1.2) ug/m3 (range 23.3-36.4) for PM10 and 41.4 (3.0) ug/m3 (range 35.4-68.0) for NO2. There were 2492 incident cases of ischemic stroke. We found no evidence of association between these pollutants and the incidence of ischemic stroke subtypes classified using the Oxford and TOAST classifications. We found no significant association with stroke severity using NIHSS severity categories. However, we found that outdoor concentrations of both PM10 and NO2 appeared to be associated with increased incidence of mild but not severe ischemic stroke, classified using the pragmatic clinical severity classification. For mild ischemic stroke, the rate ratio in the highest PM10 category by tertile was 1.20 (1.05-1.38) relative to the lowest category. The rate ratio in the highest NO2 category was 1.22 (1

  3. Report on sampling and analysis of air at trenches 218-W-4C and218-W-5 {number_sign}31 of the low level burial grounds

    SciTech Connect

    Stauffer, M.

    1997-10-06

    This report presents analytical results of air samples collected from trenches at the Low Level Burial Grounds. The samples were collected with SUMMA canisters and were analyzed by gas chromatography-mass spectrometry using a modified EPA TO-14 procedure. The data suggest that the vent pipes of the 218-W-4C trenches had elevated concentrations of volatile organic compounds. The ambient air samples collected at the 218-W-5 {number_sign}31 facility, an open trench that does not contain any waste at this time, did not show any target compounds above the method detection limit.

  4. The oxidation behavior of a model molybdenum/tungsten-containing alloy in air alone and in air with trace levels of NaCl(g)

    NASA Technical Reports Server (NTRS)

    Smeggil, J. G.; Bornstein, N. S.

    1983-01-01

    Thermogravimetric, metallographic, and X-ray studies of a model alloy, Ni-(17 a/o)Al-(10 a/o)Mo+W, oxidized in dry air at 600-1200 C and in air with 10 ppm NaCl gas at 900 C, are reported. The alloy was melted under Ar and pretreated in flowing H2 for 24 h at 1300 C. Polished 1.3 x 1.3 x 0.2-cm specimens were washed and degreased prior to oxidation in a quartz tube within a furnace for up to 120 hr. The oxidation activation energy of the alloy is determined to be about 30 kcal/mole. The specimens oxidized at 900 C and hotter exhibited oxidized and nitrided phases covered by complex NiMoO4, NiWO4, and NiAl2O4 scales and a porous, nonprotective outer layer of NiO. The oxidation behavior is found to be determined by the formation and growth of the scale, especially the (Mo,W)O2 component. Al2O3 scale layers were not formed, and further runs with pure O2 or Ar-(20 percent)O2 ruled out an explanation of this phenomenon based on aluminum nitride formation. The oxidation was accelerated by the addition of NaCl gas, a finding attributed to the reaction of NaCl with external locally protective Al2O3 scales and with the internal(Mo, W)O2 layers.

  5. Changes of plasma vWF level in response to the improvement of air quality: an observation of 114 healthy young adults.

    PubMed

    Yuan, Zhonghai; Chen, Yan; Zhang, Ying; Liu, Hui; Liu, Qian; Zhao, Jun; Hu, Min; Huang, Wei; Wang, Guangfa; Zhu, Tong; Zhang, Jim; Zhu, Ping

    2013-04-01

    Plasma von Willebrand factor (vWF) is an important factor involving in hemostasis and various cardiovascular diseases. Air pollution is related to many respiratory and cardiovascular diseases. During the Olympic Games Beijing 2008 period (August 8 to September 17, 2008) when air quality in Beijing improved greatly, we studied the relationship between plasma vWF level and the factors of air pollution index (API), ABO blood group, and polymorphisms in vWF gene in healthy young adults. We recruited 114 healthy medical students. In a period of more than 4 months around the period of Olympic Games Beijing 2008, six blood samples at stages 1 and 2 (before Olympic Games), stages 3 and 4 (during Olympic Games), and stages 5 and 6 (after Olympic Games) were taken from every participant for the measurement of plasma vWF level and genotyping of three SNPs (rs7954855, rs7965413, and rs216311) in vWF gene. Daily air pollution index near their living places was obtained from the officially published data. The average API began to decrease from stage 2, reached to nadir in stages 3 and 4, and increased but was still lower in stages 5 and 6. Plasma vWF decreased during the experimental period in all participants. The average plasma vWF decreased from stage 2 and remained lower in stages 3-6. vWF level varied greatly among the participants (from 30 to 170 %) but decreased proportionately when we analyzed their levels individually. Participants with O blood type had lower plasma vWF level than those with A, B, and AB blood types. Those with the SNP in vWF gene causing homozygous threonine at codon 1381 had lower plasma vWF level than those with homozygous alanine or heterozygous alanine/threonine. In the 114 normal individuals, the average plasma vWF level decreased during the period of Olympic Games Beijing 2008 when air quality improved greatly. This suggests that control of air pollution may be useful to prevent some diseases such as cardiovascular diseases.

  6. Drought and air warming affect the species-specific levels of stress-related foliar metabolites of three oak species on acidic and calcareous soil.

    PubMed

    Hu, Bin; Simon, Judy; Rennenberg, Heinz

    2013-05-01

    Climate change as projected for Central Europe will lead to prolonged periods of summer drought and enhanced air temperature. Thus, forest management practices are required to take into account how species performance is adapted to cope with these climate changes. Oak trees may play a major role in future forests because of their relative drought-tolerance compared with other species like beech. Therefore, this study investigated the stress responses (i.e., anti-oxidants, free amino acids) in the leaves of three widely distributed oak species in Central Europe (i.e., Quercus robur L., Q. petraea [Matt.] Libel., Q. pubescens Willd.) to drought, air warming and the combination of drought plus air warming under controlled conditions after periods of spring drought, a short rewetting and summer drought. We quantified foliar levels of thiols, ascorbate, and free amino compounds in Q robur, Q. petraea and Q. pubescens. Our study showed that oak saplings had increased levels of γ-glutamylcysteine and total glutathione and proline with drought and air warming. Foliar ascorbate, glutathione disulfide and dehydroascorbic acid levels were not affected. The comparison of stress responses to drought and/or air warming between the three species showed higher foliar thiol levels in Q. robur and Q. pubescens compared with Q. petraea. For total and reduced ascorbic acid and γ-aminobutyric acid, the highest levels were found in Q. robur. In conclusion, our study showed that foliar anti-oxidant and free amino acid levels were significantly affected by drought plus air warming; however, this effect was species-dependent with the drought-tolerant species of Q. pubescens having the highest reactive oxygen species scavenging capacity among three tested oak species. Furthermore, stress responses as shown by increased levels of foliar anti-oxidants and free amino acids differ between calcareous and acidic soil indicating that the capacities of anti-oxidative defense and osmotic stress

  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. Using community level strategies to reduce asthma attacks triggered by outdoor air pollution: a case crossover analysis

    PubMed Central

    2014-01-01

    Background Evidence indicates that asthma attacks can be triggered by exposure to ambient air pollutants, however, detailed pollution information is missing from asthma action plans. Asthma is commonly associated with four criteria pollutants with standards derived by the United States Environmental Protection Agency. Since multiple pollutants trigger attacks and risks depend upon city-specific mixtures of pollutants, there is lack of specific guidance to reduce exposure. Until multi-pollutant statistical modeling fully addresses this gap, some guidance on pollutant attack risk is required. This study examines the risks from exposure to the asthma-related pollutants in a large metropolitan city and defines the city-specific association between attacks and pollutant mixtures. Our goal is that city-specific pollution risks be incorporated into individual asthma action plans as additional guidance to prevent attacks. Methods Case-crossover analysis and conditional logistic regression were used to measure the association between ozone, fine particulate matter, nitrogen dioxide, sulfur dioxide and carbon monoxide pollution and 11,754 emergency medical service ambulance treated asthma attacks in Houston, Texas from 2004-2011. Both single and multi-pollutant models are presented. Results In Houston, ozone and nitrogen dioxide are important triggers (RR = 1.05; 95% CI: 1.00, 1.09), (RR = 1.10; 95% CI: 1.05, 1.15) with 20 and 8 ppb increase in ozone and nitrogen dioxide, respectively, in a multi-pollutant model. Both pollutants are simultaneously high at certain times of the year. The risk attributed to these pollutants differs when they are considered together, especially as concentrations increase. Cumulative exposure for ozone (0-2 day lag) is of concern, whereas for nitrogen dioxide the concern is with single day exposure. Persons at highest risk are aged 46-66, African Americans, and males. Conclusions Accounting for cumulative and concomitant outdoor

  9. Impact of the 2008 Global Recession on Air Quality over the United States: Implications for Surface Ozone Levels from Changes in NOx Emissions

    NASA Technical Reports Server (NTRS)

    Tong, Daniel; Pan, Li; Chen, Weiwei; Lamsal, Lok; Lee, Pius; Tang, Youhua; Kim, Hyuncheol; Kondragunta, Shobha; Stajner, Ivanka

    2016-01-01

    Satellite and ground observations detected large variability in nitrogen oxides (NOx) during the 2008 economic recession, but the impact of the recession on air quality has not been quantified. This study combines observed NOx trends and a regional chemical transport model to quantify the impact of the recession on surface ozone (O3) levels over the continental United States. The impact is quantified by simulating O3 concentrations under two emission scenarios: business-as-usual (BAU) and recession. In the BAU case, the emission projection from the Cross-State Air Pollution Rule is used to estimate the would-be NOx emission level in 2011. In the recession case, the actual NO2 trends observed from Air Quality System ground monitors and the Ozone Monitoring Instrument on the Aura satellite are used to obtain realistic changes in NOx emissions. The model prediction with the recession effect agrees better with ground O3 observations over time and space than the prediction with the BAU emission. The results show that the recession caused a 12ppbv decrease in surface O3 concentration over the eastern United States, a slight increase (0.51ppbv) over the Rocky Mountain region, and mixed changes in the Pacific West. The gain in air quality benefits during the recession, however, could be quickly offset by the much slower emission reduction rate during the post-recession period.

  10. Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone levels from changes in NOx emissions

    NASA Astrophysics Data System (ADS)

    Tong, Daniel; Pan, Li; Chen, Weiwei; Lamsal, Lok; Lee, Pius; Tang, Youhua; Kim, Hyuncheol; Kondragunta, Shobha; Stajner, Ivanka

    2016-09-01

    Satellite and ground observations detected large variability in nitrogen oxides (NOx) during the 2008 economic recession, but the impact of the recession on air quality has not been quantified. This study combines observed NOx trends and a regional chemical transport model to quantify the impact of the recession on surface ozone (O3) levels over the continental United States. The impact is quantified by simulating O3 concentrations under two emission scenarios: business-as-usual (BAU) and recession. In the BAU case, the emission projection from the Cross-State Air Pollution Rule is used to estimate the "would-be" NOx emission level in 2011. In the recession case, the actual NO2 trends observed from Air Quality System ground monitors and the Ozone Monitoring Instrument on the Aura satellite are used to obtain "realistic" changes in NOx emissions. The model prediction with the recession effect agrees better with ground O3 observations over time and space than the prediction with the BAU emission. The results show that the recession caused a 1-2 ppbv decrease in surface O3 concentration over the eastern United States, a slight increase (0.5-1 ppbv) over the Rocky Mountain region, and mixed changes in the Pacific West. The gain in air quality benefits during the recession, however, could be quickly offset by the much slower emission reduction rate during the post-recession period.

  11. Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus.

    PubMed

    Lefevre, Sjannie; Jensen, Frank B; Huong, Do T T; Wang, Tobias; Phuong, Nguyen T; Bayley, Mark

    2011-07-01

    In this study we investigated nitrite (NO₂⁻) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO(2max)) and critical swimming speed (U(crit)) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC₅₀ of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO(2max) and U(crit). The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO(2max) and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish.

  12. Comparison of Indoor Air Quality Management Strategies between the School and District Levels in New York State

    ERIC Educational Resources Information Center

    Lin, Shao; Kielb, Christine L.; Reddy, Amanda L.; Chapman, Bonnie R.; Hwang, Syni-An

    2012-01-01

    Background: Good school indoor air quality (IAQ) can affect the health and functioning of school occupants. Thus, it is important to assess the degree to which schools and districts employ strategies to ensure good IAQ management. We examined and compared the patterns of IAQ management strategies between public elementary schools and their school…

  13. Fuel consumption and CO2/pollutant emissions of mobile air conditioning at fleet level - new data and model comparison.

    PubMed

    Weilenmann, Martin F; Alvarez, Robert; Keller, Mario

    2010-07-01

    Mobile air conditioning (MAC) systems are the second-largest energy consumers in cars after driving itself. While different measurement series are available to illustrate their behavior in hot ambient conditions, little data are available for lower temperatures. There are also no data available on diesel vehicles, despite these being quite common in Europe (up to 70% of the fleet in some countries). In the present study, six representative modern diesel passenger cars were tested. In combination with data from previous measurements on gasoline cars, a new model was developed - EEMAC = Empa Emission model for Mobile Air Conditioning systems - to predict emissions from air conditioning. The measurements obtained show that A/C activity still occurs at temperatures below the desired interior temperature. The EEMAC model was applied to the average meteorological year of a central European region and compared with the US EPA MOBILE6 model. As temperatures in central Europe are often below 20 degrees C (the point below which the two models differ), the overall results differ clearly. The estimated average annual CO(2) output according to EEMAC is six times higher than that of MOBILE6. EEMAC also indicates that around two-thirds of the fuel used for air conditioning could be saved by switching the MAC system off below 18 degrees C.

  14. Generalized water-table and water-level data at the US Air Force plant 42 and vicinity, Palmdale, California, March-April, 1997

    USGS Publications Warehouse

    Christensen, Allen H.

    1999-01-01

    The U.S. Air Force Plant 42 (Plant 42) which is in the Antelope Valley about 1.5 miles northeast of Palmdale and 3 miles southeast of Lancaster in Los Angeles County. Historically, ground water has been the primary source of water owing, in large part, to the scarcity of surface water in the region. Since 1972, supplemental surface water has been imported from the California Water Project to help meet the demand for water. Despite the importation of surface water, ground-water withdrawal for both municipal and agricultural uses is affecting ground-water levels in the vicinity of Plant 42. To better understand the effects of ground-water withdrawal on ground-water levels and movement in the area, the U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force, constructed a generalized water-table-contour map of the aquifer system underlying Plant 42 and the surrounding area.

  15. Establishment of diagnostic reference levels for dental panoramic radiography in Greece.

    PubMed

    Manousaridis, G; Koukorava, C; Hourdakis, C J; Kamenopoulou, V; Yakoumakis, E; Tsiklakis, K

    2015-07-01

    The purpose of the present study was to present the national diagnostic reference levels (DRL) established for panoramic dental examinations in Greece. The establishment of DRL, as a tool for the optimisation of radiological procedures, is a requirement of national regulations. Measurements performed by the Greek Atomic Energy Commission on 90 panoramic systems have been used for the derivation of DRL values. DRL values have been proposed for exposure settings of different patient types (child, small adult and standard adult), both for film and digital imaging. The DRLs for different patient types are grouped in three categories: children, small adults (corresponding to female) and average adults (corresponding to male). Proposed DRLs for these groups are 2.2, 3.3 and 4.1 mGy, respectively. In order to investigate the correlation of DRLs with the available imaging modalities (CR, DR and film), this parameter was taken into account. DR imaging DRL is the lowest at 3.5 mGy, CR imaging the highest at 4.2 mGy and film imaging at 3.7 mGy. In order to facilitate comparison with other studies, kerma-width product values were calculated from Ki, air and field size.

  16. An accurate derivation of the air dose-rate and the deposition concentration distribution by aerial monitoring in a low level contaminated area

    NASA Astrophysics Data System (ADS)

    Nishizawa, Yukiyasu; Sugita, Takeshi; Sanada, Yukihisa; Torii, Tatsuo

    2015-04-01

    Since 2011, MEXT (Ministry of Education, Culture, Sports, Science and Technology, Japan) have been conducting aerial monitoring to investigate the distribution of radioactive cesium dispersed into the atmosphere after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), Tokyo Electric Power Company. Distribution maps of the air dose-rate at 1 m above the ground and the radioactive cesium deposition concentration on the ground are prepared using spectrum obtained by aerial monitoring. The radioactive cesium deposition is derived from its dose rate, which is calculated by excluding the dose rate of the background radiation due to natural radionuclides from the air dose-rate at 1 m above the ground. The first step of the current method of calculating the dose rate due to natural radionuclides is calculate the ratio of the total count rate of areas where no radioactive cesium is detected and the count rate of regions with energy levels of 1,400 keV or higher (BG-Index). Next, calculate the air dose rate of radioactive cesium by multiplying the BG-Index and the integrated count rate of 1,400 keV or higher for the area where the radioactive cesium is distributed. In high dose-rate areas, however, the count rate of the 1,365-keV peak of Cs-134, though small, is included in the integrated count rate of 1,400 keV or higher, which could cause an overestimation of the air dose rate of natural radionuclides. We developed a method for accurately evaluating the distribution maps of natural air dose-rate by excluding the effect of radioactive cesium, even in contaminated areas, and obtained the accurate air dose-rate map attributed the radioactive cesium deposition on the ground. Furthermore, the natural dose-rate distribution throughout Japan has been obtained by this method.

  17. An Analysis of the Impact of Variation in Mean Time Between Demand on Air Force Fleet Level Aircraft Parts Inventories

    DTIC Science & Technology

    2014-05-22

    21 vi OIM Operating Requirement (OIM OPERATING RQMT) ....................................... 21 Total Base Stock Level TOT BASE STK LVL (FULL...21 Depot Safety Level DEPOT SAFETY LVL (FULL) .................................................... 22...2008). Total Base Stock Level TOT BASE STK LVL (FULL) For each pick-off point, the Total Base Stock Level is the sum of the OIM base Order &Shipping

  18. Time-series ground-water-level and aquifer-system compaction data, Edwards Air Force Base, Antelope Valley, California, January 1991 through September 1993

    USGS Publications Warehouse

    Freeman, L.A.

    1996-01-01

    As part of a study by the U.S. Geological Survey, a monitoring program was implemented to collect time-series ground-water-level and aquifer-system compaction data at Edwards Air Force Base, California. The data presented in this report were collected from 18 piezometers, 3 extensometers, 1 barometer, and 1 rain gage from January 1991 through September 1993. The piezometers and extensometers are at eight sites in the study area. This report discusses the ground-water-level and aquifer-system compaction monitoring networks, and presents the recorded data in graphs. The data reported are available in the data base of the U.S. Geological Survey.

  19. Polybrominated diphenyl ethers in air and fallouts from an e-waste polluted region in southeast China: insight into levels, compositional profiles, and seasonal variation.

    PubMed

    Xu, Feng; Zhang, Gang; Wang, Junxia; Zhang, Wei; Liu, Lili; Lin, Kuangfei

    2015-12-01

    Air and fallout samples were collected seasonally in an e-waste polluted region in southeast of China in 2013-2014. The annual polybrominated diphenyl ethers (PBDEs) concentrations in air and fallout samples were 200 ± 162 pg m(-3) and 320 ± 255 ng g(-1), respectively. The deposition flux calculated from the fallout concentration was 110 ± 77.3 ng m(-2) day(-1). The PBDE levels and deposition fluxes of the samples deployed within the e-waste central area were three to four times higher than those in the surrounding area. The congener profiles in the air samples could be commonly found in commercial penta-BDE mixtures. BDE209 was the most dominant congener in fallout samples. Debromination processes were confirmed to occur both in the air and fallouts due to the minor amounts or inexistence of some congeners in technical PBDE products. The highest gaseous PBDE concentration was found during the summer while lowest during the autumn. PBDE concentration in fallouts turned up higher in the cold months while lower in the warm months. The similarity of deposition fluxes at sites in the e-waste central area indicated a steady PBDE emission source, whereas the significant relationship between deposition fluxes and particle weights at sites in the e-waste surrounding area suggested the scavenging of PBDEs in this area was largely associated with particles.

  20. Association between unemployment, income, education level, population size and air pollution in Czech cities: evidence for environmental inequality? A pilot national scale analysis.

    PubMed

    Branis, Martin; Linhartova, Martina

    2012-09-01

    We analyzed differentials in exposure to SO(2), PM(10) and NO(2) among Czech urban populations categorized according to education level, unemployment rate, population size and average annual salary. Altogether 39 cities were included in the analysis. The principal component analysis revealed two factors explaining 72.8% of the data variability. The first factor explaining 44.7% of the data variability included SO(2), PM(10), low education level and high unemployment, documenting that inhabitants with unfavorable socioeconomic status mainly reside in smaller cities with higher concentration levels of combustion-related air pollutants. The second factor explaining 28.1% of the data variability included NO(2), high salary, high education level and large population, suggesting that large cities with residents with higher socioeconomic status are exposed to higher levels of traffic-related air pollution. We conclude that, after more than a decade of free-market economy, the Czech Republic, a former Soviet satellite with a centrally planned economy, displays signs of a certain kind of environmental inequality, since environmental hazards are unevenly distributed among the Czech urban populations.

  1. Changes in Air CO2 Concentration Differentially Alter Transcript Levels of NtAQP1 and NtPIP2;1 Aquaporin Genes in Tobacco Leaves

    PubMed Central

    Secchi, Francesca; Schubert, Andrea; Lovisolo, Claudio

    2016-01-01

    The aquaporin specific control on water versus carbon pathways in leaves is pivotal in controlling gas exchange and leaf hydraulics. We investigated whether Nicotiana tabacum aquaporin 1 (NtAQP1) and Nicotiana tabacum plasma membrane intrinsic protein 2;1 (NtPIP2;1) gene expression varies in tobacco leaves subjected to treatments with different CO2 concentrations (ranging from 0 to 800 ppm), inducing changes in photosynthesis, stomatal regulation and water evaporation from the leaf. Changes in air CO2 concentration ([CO2]) affected net photosynthesis (Pn) and leaf substomatal [CO2] (Ci). Pn was slightly negative at 0 ppm air CO2; it was one-third that of ambient controls at 200 ppm, and not different from controls at 800 ppm. Leaves fed with 800 ppm [CO2] showed one-third reduced stomatal conductance (gs) and transpiration (E), and their gs was in turn slightly lower than in 200 ppm– and in 0 ppm–treated leaves. The 800 ppm air [CO2] strongly impaired both NtAQP1 and NtPIP2;1 gene expression, whereas 0 ppm air [CO2], a concentration below any in vivo possible conditions and specifically chosen to maximize the gene expression alteration, increased only the NtAQP1 transcript level. We propose that NtAQP1 expression, an aquaporin devoted to CO2 transport, positively responds to CO2 scarcity in the air in the whole range 0–800 ppm. On the contrary, expression of NtPIP2;1, an aquaporin not devoted to CO2 transport, is related to water balance in the leaf, and changes in parallel with gs. These observations fit in a model where upregulation of leaf aquaporins is activated at low Ci, while downregulation occurs when high Ci saturates photosynthesis and causes stomatal closure. PMID:27089333

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

    PubMed

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

    2000-09-01

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

  3. 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.

  4. Incidence and severity of acute respiratory illness in families exposed to different levels of air pollution, New York metropolitan area, 1971-1972

    SciTech Connect

    Love, G.J.; Lan, S.P.; Shy, C.M.; Struba, R.J.

    1981-03-01

    The incidence and severity of acute respiratory disease was studied in families in three New York communities with different ambient levels of SO/sub 2/ and particulate air pollution. Upper, lower, and total respiratory disease rates in fathers, mothers, and school children tended to be higher in the communities with higher pollution levels. Similar higher rates, however, were not observed among preschool children. Regression analyses were used to adjust rates for socioeconomic status, parental smoking, chronic bronchitis in parents, and possible indoor pollution resulting from the use of a gas stove for cooking. After these adjustments the community differences were still significant (P < .01), for school children. The indoor pollution related to gas stoves was a significant covariate among children. The effects of smoking were inconsistent. It was not possible to attribute the higher rates observed to any specific pollutant, since both SO/sub 2/ and particulate matter levels were higher in the high pollution communities, nor was it possible to attribute the excesses to current levels of exposure or to a residual effect of previous higher exposure concentrations. The fact that young children did not follow the patern suggests the latter. It was concluded, however, that current or previous exposures to the complexity of air pollutants in New York City was at least partially responsible for increased incidences of acute respiratory disease.

  5. Determination of mercaptans at microgram-per-cubic-meter levels in air by gas chromatography with photoionization detection

    SciTech Connect

    Stein, V.B.; Narang, R.S.

    1982-05-01

    A method for the gas chromatographic (GC) determination of ethyl, tert-butyl, propyl, sec-butyl, and n-butyl mercaptans in air using a photoionization detector (PID) was established by using air sampling bags. Up to 5 mL of sample was injected into a Hewlett-Packard Model 588OA GC fitted with a 9 ft glass column packed with 100/120 mesh Chromosorb W AW DMCS and coated with 15% SF-96 and 6% OV-225. The oven was held at 65 /sup 0/C and the nitrogen flow rate was 30 mL/min. The photoionization detector was attached to the GC and held at 200 /sup 0/C. The GC detection limit was determined to be 0.06 ng for n-butyl mercaptan and 0.02 ng for the remaining mercaptans with precisions (n = 8, 1sigma, 4 ng) of +/- 7.3, +/- 8.5, +/- 8.1, and +/- 10% for ethyl, tert-butyl, propyl, sec-butyl, and n-butyl mercaptan, respectively. With a 5-mL injection volume, sensitivity is about 2 ..mu..g/m/sup 3/ which is as sensitive as detection by smell since the oder threshold is about 2-4 ..mu..g/m/sup 3/.

  6. Are the residents of former Yugoslavia still exposed to elevated PCB levels due to the Balkan wars? Part 1: Air sampling in Croatia, Serbia, Bosnia and Herzegovina.

    PubMed

    Klánová, Jana; Kohoutek, Jirí; Kostrhounová, Romana; Holoubek, Ivan

    2007-08-01

    Persistent organic pollutants (POPs) spilled into the environment as a result of damaged industrial and military targets, natural resources, and infrastructure during the Balkan wars still pose a problem several years later. The aim of this project was to investigate an extent to which the residents of former Yugoslavia are exposed to elevated levels of POPs as a consequence of the wars. The atmospheric as well as the soil levels of PCBs, OCPs and PAHs were determined in Croatia, Serbia, Bosnia and Herzegovina during five high volume air sampling campaigns in 2003 and 2004. A considerable contamination of several sites was detected (PCB concentrations in the atmosphere ranged between 67 pg m(-3) and 40 ng m(-3) for the sum of 7 indicator congeners) and the levels are reported in this article.

  7. Integrating causal reasoning at different levels of abstraction. [in problem-solving system functioning as pilot assistant in commercial air transport emergencies

    NASA Technical Reports Server (NTRS)

    Hudlicka, Eva; Corker, Kevin

    1988-01-01

    In this paper, a problem-solving system which uses a multilevel causal model of its domain is described. The system functions in the role of a pilot's assistant in the domain of commercial air transport emergencies. The model represents causal relationships among the aircraft subsystems, the effectors (engines, control surfaces), the forces that act on an aircraft in flight (thrust, lift), and the aircraft's flight profile (speed, altitude, etc.). The causal relationships are represented at three levels of abstraction: Boolean, qualitative, and quantitative, and reasoning about causes and effects can take place at each of these levels. Since processing at each level has different characteristics with respect to speed, the type of data required, and the specificity of the results, the problem-solving system can adapt to a wide variety of situations. The system is currently being implemented in the KEE(TM) development environment on a Symbolics Lisp machine.

  8. Cumulative effects and threshold levels in air pollution mortality: data analysis of nine large US cities using the NMMAPS dataset.

    PubMed

    Stylianou, Mario; Nicolich, Mark J

    2009-01-01

    We examined the existence of thresholds, cumulative effects and the homogeneity of five air pollutants on the relative risk of three mortality outcomes using data from nine major US cities using data from NMMAPS. Overall, PM(10) (usually 200-day accumulation) and ozone (3-day accumulation) were the two important predictors of outcome but their effect was not uniform across the nine cities. Many models exhibited thresholds (25-45 microm g/m(3) for PM(10), and 10-45 ppb for O(3)). Our preliminary exploratory analyses suggest that the use of a linear, no threshold, model for pollution studies is not consistent with the observed data. The heterogeneity in the risk estimates across the nine cities suggests combining the local risk estimates to obtain a national risk estimate may not be justifiable and the estimate is likely to be confounded.

  9. 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.

  10. Prevalence of asthma and mean levels of air pollution: results from the French PAARC survey. Pollution Atomosphérique et Affections Respiratoires Chroniques.

    PubMed

    Baldi, I; Tessier, J F; Kauffmann, F; Jacqmin-Gadda, H; Nejjari, C; Salamon, R

    1999-07-01

    Among the possible explanations for the recent increase in the prevalence of asthma in several countries, air pollution is one of the foremost public health concerns. Data from the "Pollution Atmosphérique et Affections Respiratoires Chroniques" (PAARC) survey collected in 24 areas of seven French towns during 1974-1976 were reanalysed to assess the relationship between the prevalence of asthma and the following air pollutants: sulphur dioxide (specific (SO2) and acidimetric methods), total suspended particles (TSP), black smoke (BS), nitrogen dioxide and nitric oxide. Correlation coefficients between annual mean levels of pollution and prevalence of asthma in the different areas were first calculated. Random-effects models were then estimated. Of the 20,310 adults aged 25-59 yrs, 1,291 (6.4%) were found to be asthmatics as well as 195 (6.1%) of the 3,193 children aged 5-9 yrs. A geographical correlation between asthma and annual mean level of SO2 (ranging 17-85 microg x m(-3)) was found (r=0.45, p=0.01) in adults. No relationship was found in children. After controlling for age, educational level, smoking, and geographical clustering with a multivariate random-effects model, the relationship remained significant in adults for SO2 (odds ratio for a 50 microg x m(-3) increase=1.24, confidence interval 1.08-1.44, p=0.0035). It also remained significant when taking into account only the people reporting their last asthma attack occurring after settling in the study area. These results are consistent with the known short-term effects of SO2 in asthma and demonstrate the necessity for further studies on delayed effects of air pollution in respiratory diseases.

  11. The impact of an urban park on air pollution and noise levels in the Mediterranean city of Tel-Aviv, Israel.

    PubMed

    Cohen, Pninit; Potchter, Oded; Schnell, Izhak

    2014-12-01

    This study examines the influence of urban parks on air quality and noise in the city of Tel-Aviv, Israel, by investigation of an urban park, an urban square and a street canyon. Simultaneous monitoring of several air pollutants and noise levels were conducted. The results showed that urban parks can reduce NOx, CO and PM10 and increase O3 concentrations and that park's mitigation effect is greater at higher NOx and PM10 levels. During extreme events, mean values of 413 ppb NOx and 80 μG/m3 PM10 were measured in the street while mean values of 89 ppb NOx and 24 μG/m3 PM10 were measured in the park. Whereas summer highest O3 values of 84 ppb were measured in the street, 94 ppb were measured in the park. The benefit of the urban park in reducing NOx and PM10 concentrations is more significant than the disadvantage of increased O3 levels. Furthermore, urban parks can reduce noise by ∼5 dB(A).

  12. Capillary thermal desorption unit for near real-time analysis of VOCs at sub-trace levels. Application to the analysis of environmental air contamination and breath samples.

    PubMed

    Alonso, Mónica; Castellanos, Mar; Martín, José; Sanchez, Juan M

    2009-05-15

    A capillary microtrap thermal desorption module is developed for near real-time analysis of volatile organic compounds (VOCs) at sub-ppbv levels in air samples. The device allows the direct injection of the thermally desorbed VOCs into a chromatographic column. It does not use a second cryotrap to focalize the adsorbed compounds before entering the separation column so reducing the formation of artifacts. The connection of the microtrap to a GC-MS allows the quantitative determination of VOCs in less than 40 min with detection limits of between 5 and 10 pptv (25 degrees C and 760 mm Hg), which correspond to 19-43 ng m(-3), using sampling volumes of 775 cm(3). The microtrap is applied to the analysis of environmental air contamination in different laboratories of our faculty. The results obtained indicate that most volatile compounds are easily diffused through the air and that they also may contaminate the surrounding areas when the habitual safety precautions (e.g., working under fume hoods) are used during the manipulation of solvents. The application of the microtrap to the analysis of VOCs in breath samples suggest that 2,5-dimethylfuran may be a strong indicator of a person's smoking status.

  13. Impacts of air pollution on cultural heritage corrosion at European level: What has been achieved and what are the future scenarios.

    PubMed

    Di Turo, Francesca; Proietti, Chiara; Screpanti, Augusto; Fornasier, M Francesca; Cionni, Irene; Favero, Gabriele; De Marco, Alessandra

    2016-11-01

    The interaction of pollutants with Cultural Heritage materials leads to artworks and materials degradation and loss, causing an unpriceless damage. This works aims to estimate the impacts of air pollution and meteorological conditions on limestone, copper and bronze and represents the European risk assessment for corrosion of Cultural Heritage materials. The measures and policies for atmospheric pollution reduction have cut off the SO2 concentration and consequently its impact on materials is drastically reduced. Indeed, in 1980 the number of UNESCO sites in danger was extremely high (94% for limestone, 54% for copper and 1% for bronze) while in 2010 these sites did not exceed the tolerable value of surface recession and corrosion. However, some problem related to air pollution persists. In particular, Random Forest Analysis (RFA), highlights PM10 as the main responsible for materials corrosion, in 2010. Two scenarios in 2030 have been tested, highlighting that the corrosion levels of limestone, copper and bronze exceed the tolerable limits only in the Balkan area and Turkey. Our results show the importance in the air quality modelling as a powerful tool for the UNESCO sites conservation.

  14. Structural Impacts on Thallus and Algal Cell Components of Two Lichen Species in Response to Low-Level Air Pollution in Pacific Northwest Forests

    NASA Astrophysics Data System (ADS)

    Ra, Hyung-Shim Y.; Rubin, Laura; Crang, Richard F. E.

    2004-04-01

    Lichens have long been regarded as bioindicators of air pollution, and structural studies typically have indicated negative impacts in highly polluted areas. In this research, Parmelia sulcata and Platismatia glauca were collected from one clean and two polluted sites in the Pacific Northwest forests of the United States to investigate the anatomical and ultrastructural responses of relatively resistant lichens to moderate air pollution. Light microscopy of polluted materials revealed only slight increases in the algal cell proportions of the thallus, and a decrease in the fungal cells of the medulla. Using transmission electron microscopy, increased lipid droplets in the cytoplasm and an increase in the cell wall thickness of the photobionts were found in the polluted lichens. These results were compared with physiological data in which the net carbon uptake did not show any significant differences; however, the total chlorophyll content was heightened in the polluted samples. The increased total chlorophyll content and the absence of any changes in the algal cell proportions of the polluted samples suggest that the photobionts possessed a higher chlorophyll content per unit volume of the photobiont at polluted sites. The results also indicate that lichens have altered their storage allocation in different cellular compartments. This may be a result of symbiotic readjustment(s) between the photobiont and the mycobiont. In comparison with the physiological results from these two species, these changes do not represent damaging effects by low-level air pollution.

  15. Groundwater levels time series sensitivity to pluviometry and air temperature: a geostatistical approach to Sfax region, Tunisia.

    PubMed

    Triki, Ibtissem; Trabelsi, Nadia; Hentati, Imen; Zairi, Moncef

    2014-03-01

    In this paper, the pattern of groundwater level fluctuations is investigated by statistical techniques for 24 monitoring wells located in an unconfined coastal aquifer in Sfax (Tunisia) for a time period from 1997 to 2006. Firstly, a geostatistical study is performed to characterize the temporal behaviors of data sets in terms of variograms and to make predictions about the value of the groundwater level at unsampled times. Secondly, multivariate statistical methods, i.e., principal component analysis (PCA) and cluster analysis (CA) of time series of groundwater levels are used to classify groundwater hydrographs regard to identical fluctuation pattern. Three groundwater groups (A, B, and C) were identified. In group "A," water level decreases continuously throughout the study periods with rapid annual cyclic variation, whereas in group "B," the water level contains much less high-frequency variation. The wells of group "C" represents a steady and gradual increase of groundwater levels caused by the aquifer artificial recharge. Furthermore, a cross-correlation analysis is used to investigate the aquifer response to local rainfall and temperature records. The result revealed that the temperature is more affecting the variation of the groundwater level of group A wells than the rainfall. However, the second and the third groups are less affected by rainfall or temperature.

  16. Serum Lipid Levels in Selected Air Force Officers during the First Four Years after Graduation from the USAF Academy.

    DTIC Science & Technology

    1981-12-01

    cardiovascular disease . Since an earlier study of West Point cadets found that serum levels of cholesterol and lipoproteins rose to peak levels 2 years after graduation from the United States Military Academy, this study also followed the subjects in the study through their years at the USAF Academy and for almost 4 years thereafter. During the years at the USAF Academy, only transient elevations in serum cholesterol and uric acid levels were found, but these were apparently related to short-term stress. During the 3 1/2 to 4 years after graduation, serum cholesterol

  17. Particulate air pollution and chronic ischemic heart disease in the eastern United States: a county level ecological study using satellite aerosol data

    PubMed Central

    2009-01-01

    Background There are several known factors that cause ischemic heart disease. However, the part played by air pollution still remains something of a mystery. Recent attention has focused on the chronic effect of particulate matter on heart disease. Satellite-derived aerosol optical depth (AOD) was found to be correlated with PM2.5 in the eastern US. The objective of this study was to examine if there is an association between aerosol air pollution as indicated by AOD and chronic ischemic heart disease (CIHD) in the eastern US. Methods An ecological geographic study method was employed. Race and age standardized mortality rate (SMR) of CIHD was computed for each of the 2306 counties for the time period 2003–2004. A mean AOD raster grid for the same period was derived from Moderate Resolution Imaging Spectrometer (MODIS) aerosol data and the average AOD was calculated for each county. A bivariate Moran's I scatter plot, a map of local indicator of spatial association (LISA) clusters, and three regression models (ordinary least square, spatial lag, and spatial error) were used to analyze the relationship between AOD and CIHD SMR. Results The global Moran's I value is 0.2673 (p = 0.001), indicating an overall positive spatial correlation of CIHD SMR and AOD. The entire study area is dominated by spatial clusters of AOD against SMR (high AOD and high SMR in the east, and low AOD and low SMR in the west) (permutations = 999, p = 0.05). Of the three regression models, the spatial error model achieved the best fit (R2 = 0.28). The effect of AOD is positive and significant (beta = 0.7774, p = 0.01). Conclusion Aerosol particle pollution has adverse effect on CIHD mortality risk in the eastern US. High risk of CIHD mortality was found in areas with elevated levels of outdoor aerosol air pollution as indicated by satellite derived AOD. The evidence of the association would support targeting of policy interventions on such areas to reduce air pollution levels. Remote sensing

  18. Using improved neural network model to analyze RSP, NOx and NO2 levels in urban air in Mong Kok, Hong Kong.

    PubMed

    Lu, W Z; Wang, W J; Wang, X K; Xu, Z B; Leung, A Y T

    2003-09-01

    As the health impact of air pollutants existing in ambient addresses much attention in recent years, forecasting of air pollutant parameters becomes an important and popular topic in environmental science. Airborne pollution is a serious, and will be a major problem in Hong Kong within the next few years. In Hong Kong, Respirable Suspended Particulate (RSP) and Nitrogen Oxides NOx and NO2 are major air pollutants due to the dominant diesel fuel usage by public transportation and heavy vehicles. Hence, the investigation and prediction of the influence and the tendency of these pollutants are of significance to public and the city image. The multi-layer perceptron (MLP) neural network is regarded as a reliable and cost-effective method to achieve such tasks. The works presented here involve developing an improved neural network model, which combines the principal component analysis (PCA) technique and the radial basis function (RBF) network, and forecasting the pollutant levels and tendencies based in the recorded data. In the study, the PCA is firstly used to reduce and orthogonalize the original input variables (data), these treated variables are then used as new input vectors in RBF neural network model established for forecasting the pollutant tendencies. Comparing with the general neural network models, the proposed model possesses simpler network architecture, faster training speed, and more satisfactory predicting performance. This improved model is evaluated by using hourly time series of RSP, NOx and NO2 concentrations collected at Mong Kok Roadside Gaseous Monitory Station in Hong Kong during the year 2000. By comparing the predicted RSP. NOx and NO2 concentrations with the actual data of these pollutants recorded at the monitory station, the effectiveness of the proposed model has been proven. Therefore, in authors' opinion, the model presented in the paper is a potential tool in forecasting air quality parameters and has advantages over the traditional

  19. The Regulation of Photosynthesis in Leaves of Field-Grown Spring Wheat (Triticum aestivum L., cv Albis) at Different Levels of Ozone in Ambient Air.

    PubMed

    Lehnherr, B; Mächler, F; Grandjean, A; Fuhrer, J

    1988-12-01

    Wheat (Triticum aestivum L. cv Albis) was grown in open-top chambers in the field and fumigated daily with charcoal-filtered air (0.015 microliters per liter O(3)), nonfiltered air (0.03 microliters per liter O(3)), and air enriched with either 0.07 or 0.10 microliters per liter ozone (seasonal 8 hour/day [9 am-5 pm] mean ozone concentration from June 1 until July 10, 1987). Photosynthetic (14)CO(2) uptake was measured in situ. Net photosynthesis, dark respiration, and CO(2) compensation concentration at 2 and 21% O(2) were measured in the laboratory. Leaf segments were freeze-clamped in situ for the determination of the steady state levels of ribulose 1,5-bisphosphate, 3-phosphoglycerate, triose-phosphate, ATP, ADP, AMP, and activity of ribulose, 1,5-bisphosphate carboxylase/oxygenase. Photosynthesis of flag leaves was highest in filtered air and decreased in response to increasing mean ozone concentration. CO(2) compensation concentration and the ratio of dark respiration to net photosynthesis increased with ozone concentration. The decrease in photosynthesis was associated with a decrease in chlorophyll, soluble protein, ribulose bisphosphate carboxylase/oxygenase activity, ribulose bisphosphate, and adenylates. No decrease was found for triose-phosphate and 3-phosphoglycerate. The ratio of ATP to ADP and of triosephosphate to 3-phosphoglycerate were increased suggesting that photosynthesis was limited by pentose phosphate reductive cycle activity. No limitation occurred due to decreased access of CO(2) to photosynthetic cells since the decrease in stomatal conductance with increasing ozone concentration did not account for the decrease in photosynthesis. Ozonestressed leaves showed an increased degree of activation of ribulose bisphosphate carboxylase/oxygenase and a decreased ratio of ribulose bisphosphate to initial activity of ribulose bisphosphate carboxylase/oxygenase. Nevertheless, it is suggested that photosynthesis in ozone stressed leaves is limited by

  20. Regulatory Impact Analysis of the Final Revisions to the National Ambient Air Quality Standards for Ground-Level Ozone

    EPA Pesticide Factsheets

    The EPA performed an illustrative analysis of the potential costs, human health benefits, and welfare benefits of nationally attaining a revised primary ozone standard of 70 ppb and a primary alternative ozone standard level of 65 ppb.

  1. Relationships between mild PM10 and ozone urban air levels and spontaneous abortion: clues for primary prevention.

    PubMed

    Di Ciaula, Agostino; Bilancia, Massimo

    2015-01-01

    The effects of environmental pollution on spontaneous abortion (SAB) are still unclear. Records of SAB were collected from five cities (514,996 residents) and correlated with PM10, NO(2) and ozone levels. Median pollutant concentrations were below legal limits. Monthly SABs positively correlated with PM10 and ozone levels but not with NO(2) levels. The mean monthly SAB rate increase was estimated equal to 19.7 and 33.6 % per 10 μg/m(3) increase in PM10 or ozone concentration, respectively. Higher values of PM10 and SABs were evident in cities with- than in those without pollutant industries, with a number of SABs twofolds higher in the former group. In conclusion, SAB occurrence is affected by PM10 (particularly if industrial areas are present) and ozone concentrations, also at levels below the legal limits. Thus, SAB might be considered, at least in part, a preventable condition.

  2. Screening-level models to estimate partition ratios of organic chemicals between polymeric materials, air and water.

    PubMed

    Reppas-Chrysovitsinos, Efstathios; Sobek, Anna; MacLeod, Matthew

    2016-06-15

    Polymeric materials flowing through the technosphere are repositories of organic chemicals throughout their life cycle. Equilibrium partition ratios of organic chemicals between these materials and air (KMA) or water (KMW) are required for models of fate and transport, high-throughput exposure assessment and passive sampling. KMA and KMW have been measured for a growing number of chemical/material combinations, but significant data gaps still exist. We assembled a database of 363 KMA and 910 KMW measurements for 446 individual compounds and nearly 40 individual polymers and biopolymers, collected from 29 studies. We used the EPI Suite and ABSOLV software packages to estimate physicochemical properties of the compounds and we employed an empirical correlation based on Trouton's rule to adjust the measured KMA and KMW values to a standard reference temperature of 298 K. Then, we used a thermodynamic triangle with Henry's law constant to calculate a complete set of 1273 KMA and KMW values. Using simple linear regression, we developed a suite of single parameter linear free energy relationship (spLFER) models to estimate KMA from the EPI Suite-estimated octanol-air partition ratio (KOA) and KMW from the EPI Suite-estimated octanol-water (KOW) partition ratio. Similarly, using multiple linear regression, we developed a set of polyparameter linear free energy relationship (ppLFER) models to estimate KMA and KMW from ABSOLV-estimated Abraham solvation parameters. We explored the two LFER approaches to investigate (1) their performance in estimating partition ratios, and (2) uncertainties associated with treating all different polymers as a single "bulk" polymeric material compartment. The models we have developed are suitable for screening assessments of the tendency for organic chemicals to be emitted from materials, and for use in multimedia models of the fate of organic chemicals in the indoor environment. In screening applications we recommend that KMA and KMW be

  3. [Development of the 60Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water (N(D,w))].

    PubMed

    Fukumura, Akifumi; Mizuno, Hideyuki; Fukahori, Mai; Sakata, Suoh

    2012-01-01

    A primary standard for the absorbed dose rate to water in a 60Co gamma-ray field was established at National Metrology Institute of Japan (NMIJ) in fiscal year 2011. Then, a 60Co gamma-ray standard field for therapy-level dosimeter calibration in terms of absorbed dose to water was developed at National Institute of Radiological Sciences (NIRS) as a secondary standard dosimetry laboratory (SSDL). The results of an IAEA/WHO TLD SSDL audit demonstrated that there was good agreement between NIRS stated absorbed dose to water and IAEA measurements. The IAEA guide based on the ISO standard was used to estimate the relative expanded uncertainty of the calibration factor for a therapy-level Farmer type ionization chamber in terms of absorbed dose to water (N(D,w)) with the new field. The uncertainty of N(D,w) was estimated to be 1.1% (k = 2), which corresponds to approximately one third of the value determined in the existing air kerma field. The dissemination of traceability of the calibration factor determined in the new field is expected to diminish the uncertainty of dose delivered to patients significantly.

  4. Impact of urbanization level on urban air quality: a case of fine particles (PM(2.5)) in Chinese cities.

    PubMed

    Han, Lijian; Zhou, Weiqi; Li, Weifeng; Li, Li

    2014-11-01

    We examined and compared PM2.5 concentrations in urban and the surrounding regions, and further investigated the impact of urbanization on urban PM2.5 concentrations at the Chinese prefectures. Annual PM2.5 concentrations in most prefectures were greater than 10 μg/m(3), the air quality guideline of the World Health Organization. Those prefectures were mainly distributed along the east coast and southeast of Sichuan province; The urban PM2.5 concentrations ( [Formula: see text] ) in 85 cities were greater than (>10 μg/m(3)) those in the surrounding area. Those cities were mainly located in the Beijing-Sichuan and Shanghai-Guangxi belts. In addition, [Formula: see text] was less than (<0 μg/m(3)) that in surrounding areas in only 41 prefectures, which were located in western China or nearby mega cities; Significant positive correlations were found between [Formula: see text] and urban population (R(2) = 0.99, P < 0.05), and between [Formula: see text] and urban second industry fraction (R(2) = 0.71, P < 0.05), suggesting that urbanization had considerable impact on PM2.5 concentrations.

  5. Comparison of Air Pollution in Metropolises in China (Beijing) and Japan (Osaka and Nagoya) on the Basis of the Levels of Contaminants and Mutagenicity.

    PubMed

    Coulibaly, Souleymane; Minami, Hiroki; Abe, Maho; Furukawa, Nami; Ono, Ryo; Hasei, Tomohiro; Toriba, Akira; Tang, Ning; Hayakawa, Kazuichi; Funasaka, Kunihiro; Asakawa, Daichi; Ikemori, Fumikazu; Watanabe, Masanari; Honda, Naoko; Wakabayashi, Keiji; Watanabe, Tetsushi

    2016-01-01

    Public concern regarding the transport of air pollutants from mainland East Asia to the leeward area by the prevailing westerlies in spring and winter monsoon has been growing in recent years. We collected total suspended particle (TSP) in Beijing, a metropolis of China located windward of Japan, in spring (late February 2011-May 2011) and in winter (November 2012-early February 2013), then analyzed metals, ions, and organic compounds and mutagenicity, and compared the pollution levels with samples collected at two Japanese metropolises (Osaka and Nagoya) during the same periods. The medians of concentration of TSP and other factors in Beijing were much larger than those in the Japanese metropolises. Especially, the concentrations of polycyclic aromatic hydrocarbons (PAHs) were remarkably high in Beijing in winter, and the median of total PAHs concentration in Beijing was 62-63 times larger than that in the Japanese sites. The mutagenicity of TSP from Beijing toward Salmonella typhimurium YG1024, with and without a mammalian metabolic system (S9 mix), was 13-25 times higher than that from the Japanese sites in winter. These results suggest that air pollution levels in Beijing are very high compared with those at the two Japanese metropolises we evaluated. The diagnostic ratios of PAHs and nitrated polycyclic aromatic hydrocarbons (NPAHs) suggest that the major sources of PAHs and NPAHs in Beijing are different from those at the two Japanese sites in winter, and that the major source in Beijing is coal/biomass combustion.

  6. Sensitivity of Fermi level position at Ga-polar, N-polar, and nonpolar m-plane GaN surfaces to vacuum and air ambient

    NASA Astrophysics Data System (ADS)

    Janicki, Łukasz; Ramírez-López, Manolo; Misiewicz, Jan; Cywiński, Grzegorz; Boćkowski, Michał; Muzioł, Grzegorz; Chèze, Caroline; Sawicka, Marta; Skierbiszewski, Czesław; Kudrawiec, Robert

    2016-05-01

    Ga-polar, N-polar, and nonpolar m-plane GaN UN+ structures have been examined in air and vacuum ambient by contactless electroreflectance (CER). This technique is very sensitive to the surface electric field that varies with the Fermi level position at the surface. For UN+ GaN structures [i.e., GaN (undoped)/GaN (n-type)/substrate], a homogeneous built-in electric field is expected in the undoped GaN layer that is manifested by Franz-Keldysh oscillation (FKO) in CER spectra. A clear change in FKO has been observed in CER spectra for N-polar and nonpolar m-plane structures when changing from air to vacuum ambient. This means that those surfaces are very sensitive to ambient atmosphere. In contrast to that, only a small change in FKO can be seen in the Ga-polar structure. This clearly shows that the ambient sensitivity of the Fermi level position at the GaN surface varies with the crystallographic orientation and is very high for N-polar and nonpolar m-plane surfaces. This feature of the N-polar and nonpolar m-plane surfaces can be very important for GaN-based devices grown on these crystallographic orientations and can be utilized in some of the devices, e.g., sensors.

  7. Determining the Probability of Violating Upper-Level Wind Constraints for the Launch of Minuteman Ill Ballistic Missiles At Vandenberg Air Force Base

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Brock, Tyler M.

    2013-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman Ill ballistic missile. The 30 OSSWF requested the Applied Meteorology Unit (AMU) analyze VAFB sounding data to determine the probability of violating (PoV) upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a graphical user interface (GUI) that will calculate the PoV of each constraint on the day of launch. The AMU suggested also including forecast sounding data from the Rapid Refresh (RAP) model. This would provide further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours, and help to improve the overall upper winds forecast on launch day.

  8. AMC’s FSS Leveling Policy - How to Include in the Air Force’s Requirements System

    DTIC Science & Technology

    1999-06-01

    Two Year Demand Accommodation. If DDR = 0, yet 0 < Days Since Last Demand ( DSLD ) <= 730, then set DDR= 1/365 2. Primary Algorithm Summary. a. For NSNs...b. If DDR = 0 and 0 < DaysSinceLastDemand ( DSLD ) < 730, make DDR = 1/365 PRIMARY ALGORITHM 5. For each FSL, calculate AnticipatedRequiredLevel (ARL

  9. Development of temporally refined land-use regression models predicting daily household-level air pollution in a panel study of lung function among asthmatic children.

    PubMed

    Johnson, Markey; Macneill, Morgan; Grgicak-Mannion, Alice; Nethery, Elizabeth; Xu, Xiaohong; Dales, Robert; Rasmussen, Pat; Wheeler, Amanda

    2013-01-01

    Regulatory monitoring data and land-use regression (LUR) models have been widely used for estimating individual exposure to ambient air pollution in epidemiologic studies. However, LUR models lack fine-scale temporal resolution for predicting acute exposure and regulatory monitoring provides daily concentrations, but fails to capture spatial variability within urban areas. This study coupled LUR models with continuous regulatory monitoring to predict daily ambient nitrogen dioxide (NO(2)) and particulate matter (PM(2.5)) at 50 homes in Windsor, Ontario. We compared predicted versus measured daily outdoor concentrations for 5 days in winter and 5 days in summer at each home. We also examined the implications of using modeled versus measured daily pollutant concentrations to predict daily lung function among asthmatic children living in those homes. Mixed effect analysis suggested that temporally refined LUR models explained a greater proportion of the spatial and temporal variance in daily household-level outdoor NO(2) measurements compared with daily concentrations based on regulatory monitoring. Temporally refined LUR models captured 40% (summer) and 10% (winter) more of the spatial variance compared with regulatory monitoring data. Ambient PM(2.5) showed little spatial variation; therefore, daily PM(2.5) models were similar to regulatory monitoring data in the proportion of variance explained. Furthermore, effect estimates for forced expiratory volume in 1 s (FEV(1)) and peak expiratory flow (PEF) based on modeled pollutant concentrations were consistent with effects based on household-level measurements for NO(2) and PM(2.5). These results suggest that LUR modeling can be combined with continuous regulatory monitoring data to predict daily household-level exposure to ambient air pollution. Temporally refined LUR models provided a modest improvement in estimating daily household-level NO(2) compared with regulatory monitoring data alone, suggesting that this

  10. Multi-year levels and trends of non-methane hydrocarbon concentrations observed in ambient air in France

    NASA Astrophysics Data System (ADS)

    Waked, Antoine; Sauvage, Stéphane; Borbon, Agnès; Gauduin, Julie; Pallares, Cyril; Vagnot, Marie-Pierre; Léonardis, Thierry; Locoge, Nadine

    2016-09-01

    Measurements of 31 non-methane hydrocarbons (NMHCs) were carried out at three urban (Paris, 2003-2014, Strasbourg, 2002-2014 and Lyon, 2007-2014) sites in France over the period of a decade. A trend analysis was applied by means of the Mann-Kendall non-parametric test to annual and seasonal mean concentrations in order to point out changes in specific emission sources and to assess the impact of emission controls and reduction strategies. The trends were compared to those from three rural sites (Peyrusse-Vieille, 2002-2013, Tardière, 2003-2013 and Donon, 1997-2007). The results obtained showed a significant yearly decrease in pollutant concentrations over the study period and for the majority of species in the range of -1 to -7% in accordance with the decrease of NMHC emissions in France (-5 to -9%). Concentrations of long-lived species such as ethane and propane which are recognized as tracers of distant sources and natural gas remained constant. Compounds associated with combustion processes such as acetylene, propene, ethylene and benzene showed a significant decline in the range of -2% to -5% yr-1. These trends are consistent with those recently described at urban and background sites in the northern mid-latitudes and with emission inventories. C7-C9 aromatics such as toluene and xylenes as well as C4-C5 alkanes such as isopentane and isobutane also showed a significant decrease in the range of -3% to -7% yr-1. The decreasing trends in terms of % yr-1 observed at these French urban sites were typically higher for acetylene, ethylene and benzene than those reported for French rural sites of the national observatory of Measurement and Evaluation in Rural areas of trans-boundary Air pollution (MERA). The study also highlighted the difficult choice of a long term sampling site representative of the general trends of pollutant concentrations.

  11. Data from stratigraphic test holes drilled at the U.S. Marine Corps Air Station, Cherry Point, North Carolina, 1994-2001, and periodic water levels, 2000-2003

    USGS Publications Warehouse

    Wrege, Beth M.; Jen, Philip S.

    2004-01-01

    Nine stratigraphic test holes, from 158 to 305 feet deep, were drilled at the U.S. Marine Corps Air Station at Cherry Point, North Carolina, between 1994 and 2001 by the U.S. Geological Survey. These test holes and subsequent wells provide information about the lithology, stratigraphy, and geology at the Marine Corps Air Station. In addition, ground-water-level data were collected at the Air Station through 2003. The U.S. Geological Survey also conducted high-resolution marine and land seismic surveys during this investigation. The ground-water-level data and locations of the seismic survey lines are included in this report. The stratigraphic data combined with the seismic data provide a basis for the delineation of paleochannels beneath the Air Station as well as information for the management of water resources at the Air Station.

  12. Association Between Changes in Air Pollution Levels During the Beijing Olympics and Biomarkers of Inflammation and Thrombosis in Healthy Young Adults

    PubMed Central

    Rich, David Q.; Kipen, Howard M.; Huang, Wei; Wang, Guangfa; Wang, Yuedan; Zhu, Ping; Ohman-Strickland, Pamela; Hu, Min; Philipp, Claire; Diehl, Scott R.; Lu, Shou-En; Tong, Jian; Gong, Jicheng; Thomas, Duncan; Zhu, Tong; Zhang, Junfeng (Jim)

    2014-01-01

    Context Air pollution is a risk factor for cardiovascular diseases (CVD), but the underlying biological mechanisms are not well understood. Objective To determine whether markers related to CVD pathophysiological pathways (biomarkers for systemic inflammation and thrombosis, heart rate, and blood pressure) are sensitive to changes in air pollution. Design, Setting, and Participants Using a quasi-experimental opportunity offered by greatly restricted air pollution emissions during the Beijing Olympics, we measured pollutants daily and the outcomes listed below in 125 healthy young adults before, during, and after the 2008 Olympics (June 2-October 30). We used linear mixed-effects models to estimate the improvement in outcome levels during the Olympics and the anticipated reversal of outcome levels after pollution controls ended to determine whether changes in outcome levels were associated with changes in pollutant concentrations. Main Outcome Measures C-reactive protein (CRP), fibrinogen, von Willebrand factor, soluble CD40 ligand (sCD40L), soluble P-selectin (sCD62P) concentrations; white blood cell count (WBC); heart rate; and blood pressure. Results Concentrations of particulate and gaseous pollutants decreased substantially (−13% to −60%) from the pre-Olympic period to the during-Olympic period. Using 2-sided tests conducted at the .003 level, we observed statistically significant improvements in sCD62P levels by −34.0% (95% CI, −38.4% to −29.2%; P<.001) from a pre-Olympic mean of 6.29 ng/mL to a during-Olympic mean of 4.16 ng/mL and von Willebrand factor by −13.1% (95% CI, −18.6% to −7.5%; P<.001) from 106.4% to 92.6%. After adjustments for multiple comparisons, changes in the other outcomes were not statistically significant. In the post-Olympic period when pollutant concentrations increased, most outcomes approximated pre-Olympic levels, but only sCD62P and systolic blood pressure were significantly worsened from the during-Olympic period

  13. Passive Badge Assessment for Long-term, Low-level Air Monitoring on Submarines: Nitrogen Dioxide Badge Validation

    DTIC Science & Technology

    2005-10-31

    SO2NH2 + HN NH2 HN NH2 N N SO2NH2 Red color developement Sulfanilamide NEDA Derivative Product Figure 5. Chemistry... naphthyl ) ethylenediamine dihydrochloride (NEDA) solution were added, mixing thoroughly between each reagent addition. The flask was filled to the 50...levels being extracted, relative to the 6014 method. One milliliter of hydrogen peroxide solution, 10 mL sulfanilamide solution, and 1.4 mL N -(1

  14. Issues in RF propagation modeling in an urban environment using the Extended Air Defense Simulation (EADSIM) mission level model.

    SciTech Connect

    Booher, Stephen R.; Bacon, Larry Donald

    2006-02-01

    As military operations in urban environments become more numerous, the ability of combat units to communicate, jam enemy communications, or employ RF weapons within this environment must be evaluated. To perform this evaluation in a mission level model requires a capability to evaluate the contributions of both terrain and man-made structures (interior and exterior) to RF propagation. The present study is an analysis of the adequacy of a mission level model (EADSIM) to perform these RF propagation calculations in an urban environment. Three basic environments must be assessed. The first environment consists entirely of terrain, with no man-made features impacting propagation values. The second environment includes terrain, but also includes the contribution of solid structures with abrupt edges, which may obstruct/influence LOS paths. The third environment includes not only terrain and structures, but also contains structures with interior features which must be evaluated to determine the propagation levels within and around these structures. EADSIM was used as the model for evaluation in view of its suite of propagation tools which can be used for analysis of RF propagation between transmitters and receivers including terrain. To assess EADSIM's capability to perform in these environments, flat terrain maps with an obstruction were created to permit comparison of EADSIM's propagation models with analytical calculations and with measurements. Calculations from the Terrain Integrated Rough Earth Model (TIREM) and the Spherical Earth Knife Edge (SEKE) propagation models included within EADSIM showed that the ability of the models to calculate knife-edge diffraction agreed favorably with analytical values. The representation of multipath effects was less encouraging. SEKE only models multipath when Fresnel clearance exists. TIREM models multipath, but the cyclical characteristics of multipath are not represented, and only subtractive path loss is considered. Multipath

  15. Environmental Noise Assessment for Military Aircraft Training Routes. Volume 1. SAC (Strategic Air Command) Low-Level Routes.

    DTIC Science & Technology

    1987-04-01

    Det 24 IR-986 43 SW Andersen AFB GU 2000/1000 320 Det 24 IR-982 43 SW Osan AB, Korea 1000 320 Det 9 Bann STR HQ USAFE/DOOB Bann , Germany Det 4 STRC HQ...operates under the MS-DOS operating system. A BASIC program was used to initialize and program the LD-700s, and to read data and store them for subsequent...dB (L eq) Interval Data Interval Period I Hour Basic Data Stored Leq , SEL, Lmax Lmi n Statistical Levels L01 , L10 , L50 , L9 0 Exceedance Counts RMS

  16. Ground-water-level monitoring, basin boundaries, and potentiometric surfaces of the aquifer system at Edwards Air Force Base, California, 1992

    USGS Publications Warehouse

    Rewis, D.L.

    1995-01-01

    A ground-water-level monitoring program was implemented at Edwards Air Force Base, California, from January through December 1992 to monitor spatial and temporal changes in poten-tiometric surfaces that largely are affected by ground-water pumping. Potentiometric-surface maps are needed to determine the correlation between declining ground- water levels and the distribution of land subsidence. The monitoring program focused on areas of the base where pumping has occurred, especially near Rogers Lake, and involved three phases of data collection: (1) well canvassing and selection, (2) geodetic surveys, and (3) monthly ground-water-level measurements. Construction and historical water- level data were compiled for 118 wells and pi-ezometers on or near the base, and monthly ground-water-level measurements were made in 82 wells and piezometers on the base. The compiled water-level data were used in conjunction with previously collected geologic data to identify three types of no-flow boundaries in the aquifer system: structural boundaries, a principal-aquifer boundary, and ground-water divides. Heads were computed from ground-water-level measurements and land-surface altitudes and then were used to map seasonal potentiometric surfaces for the principal and deep aquifers underlying the base. Pumping has created a regional depression in the potentiometric surface of the deep aquifer in the South Track, South Base, and Branch Park well-field area. A 15-foot decline in the potentiometric surface from April to September 1992 and 20- to 30-foot drawdowns in the three production wells in the South Track well field caused locally unconfined conditions in the deep aquifer.

  17. Air Quality Guide for Ozone

    MedlinePlus

    Local Air Quality Conditions Zip Code: State : My Current Location Air Quality Guide for Ozone Ground-level ozone is one ... exposure and protect your health. For your local air quality, visit www.airnow.gov View or print guide ...

  18. Relation of ST-Segment Elevation Myocardial Infarction to Daily Ambient Temperature and Air Pollutant Levels in a Japanese Nationwide Percutaneous Coronary Intervention Registry.

    PubMed

    Yamaji, Kyohei; Kohsaka, Shun; Morimoto, Takeshi; Fujii, Kenshi; Amano, Tetsuya; Uemura, Shiro; Akasaka, Takashi; Kadota, Kazushige; Nakamura, Masato; Kimura, Takeshi

    2017-03-15

    Effects of daily fluctuation of ambient temperature and concentrations of air pollutants on acute cardiovascular events have not been well studied. From January 2011 to December 2012, a total of 56,863 consecutive ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention were registered from 929 institutes with median interinstitutional distance of 2.6 km. We constructed generalized linear mixed models in which the presence or absence of patients with STEMI per day per institute was included as a binomial response variable, with daily meteorologic and environmental data obtained from their respective observatories nearest to the institutes (median distance of 9.7 and 5.6 km) as the explanatory variables. Both lower mean temperature and increase in maximum temperature from the previous day were independently associated with the STEMI occurrence throughout the year (odds ratio [OR] 0.925, 95% confidence interval [CI] 0.915 to 0.935, per 10°C, p <0.001; and OR 1.012, 95% CI 1.009 to 1.015, per °C, p <0.001, respectively). Decrement in minimum temperature from -4 days to -3 days before the event date was marginally associated with the STEMI occurrence, only during the wintertime (OR 0.991, 95% CI 0.982 to 0.999, per °C, p = 0.03). As for the air pollutants, nitrogen oxides and suspended particle matter were not correlated with the occurrence of STEMI after adjusting for the meteorologic and livelihood variables. Both the absolute value and relative change in the ambient temperature were associated with the occurrence of STEMI; the associations with the air pollutant levels were less clear after adjustment for these meteorologic variables in Japan.

  19. Characteristics of air quality and sources affecting fine particulate matter (PM2.5) levels in the City of Red Deer, Canada.

    PubMed

    Bari, Md Aynul; Kindzierski, Warren B

    2017-02-01

    With concern about levels and exceedances of Canadian and provincial standards and objectives for fine particulate matter (PM2.5) in recent years, an investigation of air quality characteristics and potential local and long-range sources influencing PM2.5 concentrations was undertaken in the City of Red Deer, Alberta. The study covered the period May 2009 to December 2015. Comparatively higher concentrations of PM2.5 were observed in winter (mean: 11.6 μg/m(3), median: 10 μg/m(3)) than in summer (mean: 9.0 μg/m(3), median: 7.0 μg/m(3)). Exceedances of the 1 h Alberta Ambient Air Quality objective (3-31 times per year > 80 μg/m(3)) and the 24 h Canada-Wide Standard (2-11 times per year > 30 μg/m(3)) were found at the Red Deer Riverside air monitoring station, particularly in 2010, 2011 and 2015. Positive matrix factorization (PMF) followed by multiple linear regression (MLR) analysis identified a mixed industry/agriculture factor as the dominant contributor to PM2.5 (39.3%), followed by an O3-rich (biogenic) factor (26.4%), traffic (19.3%), biomass burning (10.5%) and a mixed urban factor (4.4%). In addition to local traffic, the mixed industry/agriculture factor - inferred as mostly upstream oil and gas emission sources surrounding Red Deer - was identified as another potentially important source contributing to wintertime high PM2.5 pollution days. These findings offer useful preliminary information about current PM2.5 sources and their potential contributions in Red Deer; and this information can support policy makers in the development of particulate matter control strategies if required.

  20. High-resolution simulation of link-level vehicle emissions and concentrations for air pollutants in a traffic-populated eastern Asian city

    NASA Astrophysics Data System (ADS)

    Zhang, Shaojun; Wu, Ye; Huang, Ruikun; Wang, Jiandong; Yan, Han; Zheng, Yali; Hao, Jiming

    2016-08-01

    Vehicle emissions containing air pollutants created substantial environmental impacts on air quality for many traffic-populated cities in eastern Asia. A high-resolution emission inventory is a useful tool compared with traditional tools (e.g. registration data-based approach) to accurately evaluate real-world traffic dynamics and their environmental burden. In this study, Macau, one of the most populated cities in the world, is selected to demonstrate a high-resolution simulation of vehicular emissions and their contribution to air pollutant concentrations by coupling multimodels. First, traffic volumes by vehicle category on 47 typical roads were investigated during weekdays in 2010 and further applied in a networking demand simulation with the TransCAD model to establish hourly profiles of link-level vehicle counts. Local vehicle driving speed and vehicle age distribution data were also collected in Macau. Second, based on a localized vehicle emission model (e.g. the emission factor model for the Beijing vehicle fleet - Macau, EMBEV-Macau), this study established a link-based vehicle emission inventory in Macau with high resolution meshed in a temporal and spatial framework. Furthermore, we employed the AERMOD (AMS/EPA Regulatory Model) model to map concentrations of CO and primary PM2.5 contributed by local vehicle emissions during weekdays in November 2010. This study has discerned the strong impact of traffic flow dynamics on the temporal and spatial patterns of vehicle emissions, such as a geographic discrepancy of spatial allocation up to 26 % between THC and PM2.5 emissions owing to spatially heterogeneous vehicle-use intensity between motorcycles and diesel fleets. We also identified that the estimated CO2 emissions from gasoline vehicles agreed well with the statistical fuel consumption in Macau. Therefore, this paper provides a case study and a solid framework for developing high-resolution environment assessment tools for other vehicle-populated cities

  1. Levels of short chain chlorinated paraffins in pine needles and bark and their vegetation-air partitioning in urban areas.

    PubMed

    Wang, Thanh; Yu, Junchao; Han, Shanlong; Wang, Yawei; Jiang, Guibin

    2015-01-01

    Short chain chlorinated paraffins (SCCPs) have been of considerable concern in recent years due to their high production volumes, environmental persistency and potential for long range atmospheric transport. Vegetation can take up considerable amounts of semivolatile organic compounds from the atmosphere and can act as indicators of local contamination. Paired pine needles and bark were sampled around Beijing during winter and summertime to investigate the distribution of SCCPs in urban areas. Levels in bark samples ranged 5.79-37.5 μg/g on a lipid normalized basis (lw) with a geometric mean (GM) of 16.9 μg/g lw whereas levels were 3.03-40.8 (GM 11.8) μ/g lw for needles. Average congener group abundance profiles showed equal contribution of all four carbon groups (C(10-13)) in wintertime where as higher abundances of C(10) and C(11) groups were found during summer. Uptake of SCCPs occurred mainly via kinetically limited gaseous deposition and particle bound deposition in the investigated area.

  2. Excretion of N-mononitrosopiperazine after low level exposure to piperazine in air: effects of dietary nitrate and ascorbate

    SciTech Connect

    Bellander, T.; Osterdahl, B.G.; Hagmar, L.

    1988-04-01

    The secondary amine piperazine may be nitrosated in vivo, following oral intake or occupational exposure by inhalation. The suspected carcinogen N-mononitrosopiperazine could be formed in the human stomach, and in part excreted in the urine. In this study, 0.4 microgram N-mononitrosopiperazine, determined by gas chromatography-Thermal Energy Analysis, was observed in the urine in one of four volunteers, at an experimental exposure by inhalation of 0.3 mg piperazine/m3. The intake of spinach and beetroot caused an increased nitrosation of piperazine, and up to 1.7 microgram N-mononitrosopiperazine was excreted in the urine in the four individuals. This excretion indicates that about 5% of the absorbed piperazine dose was converted to N-mononitrosopiperazine. With the same nitrate-rich diet, but with the addition of citrus fruits and fresh vegetables, the highest excretion was 0.6 microgram N-mononitrosopiperazine. The excretion was significantly correlated with the ratio between the maximum level of nitrite in saliva and the ascorbate level in plasma. There was also a significant interindividual variation. N,N'-Dinitrosopiperazine was not found in any sample of urine.

  3. Influence of a municipal solid waste incinerator on ambient air PCDD/F levels: a comparison of running and non-running periods.

    PubMed

    Zhang, Manwen; Zhang, Sukun; Zhang, Zhengquan; Xu, Zhengcheng; Feng, Guixian; Ren, Mingzhong

    2014-09-01

    The concentration of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the ambient air of a municipal solid waste incinerator (MSWI) during its running and non-running periods was monitored in this study to investigate the contribution of the MSWI to PCDD/F pollution in the vicinal environment. Results show that the PCDD/F levels for the normal MSWI running period and after shut-down ranged 0.156-1.44 pg I-TEQ/m(3) (0.514 pg I-TEQ/m(3)) and 0.158-0.648 pg I-TEQ/m(3) (0.345 pg I-TEQ/m(3)), respectively. Significant differences were found between the results of the two surveys in 2011 and 2012. High PCDD/F levels were observed in two of the seven study sites in 2011, and these levels directly declined in 2012. A dramatic increase in PCDD/F concentrations was observed in two sites in 2012. Comparison of congener and homologue fingerprint characteristics in the two surveys, together with principal component analysis, revealed that the PCDD/F levels in all of the samples collected in 2012 and in three of the samples collected in 2011 are mainly influenced by heavy traffic. MSWI is the primary PCDD/F emission sources of the PCDD/Fs detected in the remaining samples collected in 2011.

  4. Microenvironmental air and soil monitoring of contaminants: An evaluation of indoor and outdoor levels in Chihuahua City

    NASA Astrophysics Data System (ADS)

    Delgado-Rios, Marcos

    Like most of the cities around the world Chihuahua City suffers atmospheric and soil pollution. This is a problem that requires immediate attention from both public authorities and the scientific community. Although it is known that high levels of heavy metals are present in the airborne particulate matter, soil and dust in many urban regions, the information about personal exposure to these pollutants in Chihuahua City is nonexistent. This study focuses on the analysis and characterization of lead and arsenic in the airborne and soil particulate matter present in the interiors of households and their surrounding outdoor environments in the southern part of Chihuahua City. The sampling area chosen for this study was located in the southern part of Chihuahua City. An atmospheric sampling point selected by the Centro de Investigacion en Materiales Avanzados (CIMAV) was selected as a geographical center, with a 2 km radius forming the sampling area. The households selected for analyses were located on Lombardo Toledano Street, a high-traffic street. The main objectives of this study were to establish the maximum exposure level in outdoor and indoor environments for particulate matter less than 10 mum (PM 10), Pb, and As, to determine the background level of Chihuahua City for these same elements, to determine the isotopic ratios of Pb206 and Pb207 in the indoor and outdoor atmospheric samples, and to verify if the source of the pollution is from anthropogenic and/or natural sources. Additionally, a comparison of the analytical data from X-ray fluorescence (XRF) versus the analytical data from inductively coupled plasma with optical emission spectroscopy (ICP-OES) was conducted. The comparison of these techniques was based on sample preparation, speed of analysis, and accuracy of results. In the case of sample preparation, two extraction techniques were performed for a comparison of the extraction/leaching of Pb and As from the samples. These microwave

  5. The level of air pollution in the impact zone of coal-fired power plant (Karaganda City) using the data of geochemical snow survey (Republic of Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Adil'bayeva, T. E.; Talovskaya, A. V.; Yazikov, Ye G.; Matveenko, I. A.

    2016-09-01

    Coal-fired power plants emissions impact the air quality and human health. Of great significance is assessment of solid airborne particles emissions from those plants and distance of their transportation. The article presents the results of air pollution assessment in the zone of coal-fired power plant (Karaganda City) using snow survey. Based on the mass of solid airborne particles deposited in snow, time of their deposition on snow at the distance from 0.5 to 4.5 km a value of dust load has been determined. It is stated that very high level of pollution is observed at the distance from 0.5 to 1 km. there is a trend in decrease of dust burden value with the distance from the stacks of coal-fired power plant that may be conditioned by the particle size and washing out smaller ash particles by ice pellets forming at freezing water vapour in stacks of the coal-fired power plant. Study in composition of solid airborne particles deposited in snow has shown that they mainly contain particulates of underburnt coal, Al-Si- rich spheres, Fe-rich spheres, and coal dust. The content of the particles in samples decreases with the distance from the stacks of the coal-fired power plant.

  6. Hydrogeologic setting, water levels, and quality of water from supply wells at the US Marine Corps Air Station, Cherry Point, North Carolina

    USGS Publications Warehouse

    Lloyd, O.B.; Daniel, C. C.

    1988-01-01

    The Marine Corps Air Station is located in the Coastal Plain province of North Carolina. Four freshwater aquifers of sand and limestone underlie the area to a depth of about 500 feet. Saline water occurs below this depth. The aquifers are separated by three confining units that are thin and discontinuous in the southern part. Water supply is obtained from 195- to 330 feet wells in the Castle Hayne aquifer. Many wells are near landfills that have received hazardous wastes. Groundwater withdrawals have reduced hydraulic heads in the Castle Hayne some 20 feet around active production wells, creating potential for downward movement of contaminated water from the surface and for upward movement of saline water that occurs at depth. Chemical analyses of water from the Castle Hayne aquifer indicate median concentrations of iron and manganese are 0.78 and 0.08 milligrams per liter, respectively, and lead and (or) nickel exceed drinking water standards in three wells. Chloride increased from 10 to more than 40 milligrams per liter in the deepest operating well over a 45-year period. Benzene concentrations range from 0.5 to 1.9 milligrams per liter in the southern part of the Air Station but were below the 5 milligrams per liter maximum contaminant level for drinking water. Fatty acids were found in concentrations as much as 28 micrograms per liter in water from wells in an area centered around the intersection of Roosevelt Boulevard and Slocum Road. Resampling is needed to verify all constituents that indicate contamination.

  7. A kinematic investigation of the influence of anvil air flow over convective nephsystems on high-level horizontal flow

    NASA Technical Reports Server (NTRS)

    Balogun, E. E.

    1977-01-01

    The interactions between horizontal ambient flow and divergent wind fields, such as those that obtain atop cumulonimbus complexes, were investigated (theoretically) kinematically. The following were observed from the results of the analyses. First, for a particular divergent field, the relative mass flux over the area of the nephsystem decreased as the strength of the horizontal flow increased. Secondly, while in some of the cases analyzed the interaction between the two flows only resulted in the fanning out of streamlines and a slight redistribution in the wind speed, in many cases backflows and a total reorganization of the wind field occurred. Backflows have a blocking effect on the horizontal flow. Some of the computed patterns were compared with upper level cloud vectors (from geostationary satellite photographs). The comparison indicated that the computed resultant wind field could be used to explain some features of such satellite-derived wind fields.

  8. [Investigation of mold fungi in air samples of elementary schools and evaluation of allergen-specific IgE levels in students' sera].

    PubMed

    Ovet, Habibe; Ergin, Cağrı; Kaleli, Ilknur

    2012-04-01

    Atmospheric fungal spores play important role in allergic reactions in atopic individuals. Monitorization of those spores found in the environment of atopic cases is crucial for the choice of the antigens that will be included in allergen screening procedures and precautions to be taken against mold-originated health problems. Since most of the people spend plenty of time indoors in recent years, the effects of exposure to indoor air fungi on human health have gained importance. This study was aimed to investigate the indoor air mold distribution of elementary schools in Denizli province (located in west Anatolia, Turkey) and to compare the allergen-specific IgE levels of children against the most frequently detected mold genus. A questionnaire (MM080) was distributed to the 4967 students (6-8 year-old) attending first and second degrees of 16 different elementary schools with scattered locations in city center. This questionnaire form included the questions related to the general information about the child, school environment, allergic complaints since last year, home environment and nutrition. Response rate to the questionnaire was 51.6% (2565/4967). Air samples were collected from 18 classrooms in March 2009, during which high rates of allergic symptoms were observed according to the questionnaire results. Mold fungi belonging to 10 different genera (Penicillium spp. 46%; Aspergillus spp. 18%; Cladosporium spp. 17%; Alternaria spp. 15%; Drechslera spp. 1%; Chrysosporium, Fusarium, Conidiobolus and Cladothecium species 0.5%; unidentified 1%) were isolated from indoor air of classrooms. Since the most frequently detected mold was Penicillium spp. (46%), the 48 children with atopic symptoms were called to the hospital for the determination of total IgE and Penicillium specific IgE in their sera. Twenty two students accepted the invitation and serum total IgE (Immulite 2000; Diagnostic Product Corporation, USA) and allergen-specific IgE (Penicillium brevicompactum

  9. Levels, isomer profiles and chiral signatures of particle-bound hexabromocyclododecanes in ambient air around Shanghai, China.

    PubMed

    Li, Huiru; Mo, Ligui; Yu, Zhiqiang; Sheng, Guoying; Fu, Jiamo

    2012-06-01

    Hexabromocyclododecanes (HBCDs) have been considered candidate persistent organic pollutants, however, environmental data on their presence in China, a major world market, are limited. In this study, airborne particle-bound HBCDs in Shanghai, China were quantified with liquid chromatography-tandem mass spectrometry, and their total concentrations varied from 3.21 to 123 pg/m(3). The industrial area showed about three times higher HBCD levels than the urban areas. Gamma-HBCD dominated in particle-associated HBCDs in the industrial area, while α-HBCD was the major diastereomer of the urban areas, which is quite different from the pattern of technical products. Besides α-, β- and γ-HBCDs, δ-HBCD was also detected in all samples (0.09-6.31 pg/m(3)), while no ɛ-HBCD was found. Airborne β- and γ-HBCDs were racemic in most studied areas due to their chiral signatures showing no significant difference from commercial mixture. Fractions of (+)-α-HBCD (0.417-0.467), however, suggested the enrichment of (-)-α-HBCD and the involvement of enantioselective bioprocesses.

  10. Air Research

    EPA Pesticide Factsheets

    EPA's air research provides the critical science to develop and implement outdoor air regulations under the Clean Air Act and puts new tools and information in the hands of air quality managers and regulators to protect the air we breathe.

  11. Traffic-related air pollution and circulating levels of total and allergen-specific IgE among children in Detroit, Michigan

    EPA Science Inventory

    Introduction: There is a growing body of literature suggesting a relationship between traffic-related air pollution and allergic health outcomes. Animal studies have demonstrated that air pollution, particularly diesel exhaust particles, may stimulate or enhance atopic responses...

  12. Ground-Water Levels and Water-Quality Data for Wells in the Crumpton Creek Area near Arnold Air Force Base, Tennessee, November 2001 to January 2002

    USGS Publications Warehouse

    Williams, Shannon D.

    2003-01-01

    From November 2001 to January 2002, a study of the ground-water resources in the Crumpton Creek area of Middle Tennessee was conducted to determine whether volatile organic compounds (VOCs) from Arnold Air Force Base (AAFB) have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. VOC samples were collected from private wells that were not included in previous sampling efforts conducted in the Crumpton Creek area near AAFB. Ground-water-flow directions were investigated by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 68 private wells, 82 monitoring wells, and 1 cave during the period of study. Ground-water levels were determined for 42 of the private wells and for all 82 monitoring wells. Of the 82 monitoring wells, 81 withdraw water from the Manchester aquifer and 1 well withdraws water from the overlying shallow aquifer. The Manchester aquifer wells range in depth from 20 to 150 feet. Water-level altitudes for the Manchester aquifer ranged from 956 to 1,064 feet above the National Geodetic Vertical Datum of 1929. Water levels ranged from approximately 6 feet above land surface to 94 feet below land surface. Water-quality samples were collected from all 68 private wells, 8 of the monitoring wells, and the 1 cave. Of the 55 VOCs analyzed, 42 were not detected. Thirteen VOCs were detected; however, only tetrachloroethylene (PCE), methylene chloride, and toluene were detected at concentrations equal to or above reporting levels for the analytical method used. PCE was detected in water samples from 15 private wells and was the only VOC that exceeded drinking water maximum contaminant levels for public water systems. PCE concentrations in samples from five of the wells were below the reporting level and ranged from estimated concentrations of 0.46 to 0.80 microgram per liter (?g/L). Samples from 10

  13. Multi-Level Wild Land Fire Fighting Management Support System for an Optimized Guidance of Ground and Air Forces

    NASA Astrophysics Data System (ADS)

    Almer, Alexander; Schnabel, Thomas; Perko, Roland; Raggam, Johann; Köfler, Armin; Feischl, Richard

    2016-04-01

    -fighting missions. The ongoing development focuses on the following topics: (1) Development of a multi-level management solution to coordinate and guide different airborne and terrestrial deployed firefighting modules as well as related data processing and data distribution activities. (2) Further, a targeted control of the thermal sensor based on a rotating mirror system to extend the "area performance" (covered area per hour) in time critical situations for the monitoring requirements during forest fire events. (3) Novel computer vision methods for analysis of thermal sensor signatures, which allow an automatic classification of different forest fire types and situations. (4) A module for simulation-based decision support for planning and evaluation of resource usage and the effectiveness of performed fire-fighting measures. (5) Integration of wearable systems to assist ground teams in rescue operations as well as a mobile information system into innovative command and fire-fighting vehicles. In addition, the paper gives an outlook on future perspectives including a first concept for the integration of the near real-time multilevel forest fire fighting management system into an "EU Civil Protection Team" to support the EU civil protection modules and the Emergency Response Coordination Centre in Brussels. Keywords: Airborne sensing, multi sensor imaging, near real-time fire monitoring, simulation-based decision support, forest firefighting management, firefighting impact analysis.

  14. Micronucleus formation, DNA damage and repair in premenopausal women chronically exposed to high level of indoor air pollution from biomass fuel use in rural India.

    PubMed

    Mondal, Nandan Kumar; Mukherjee, Bidisha; Das, Debangshu; Ray, Manas Ranjan

    2010-03-29

    Genotoxicity of indoor air pollution from biomass fuel use has been examined in 132 biomass users (median age 34 years) and 85 age-matched control women from eastern India who used the cleaner fuel liquefied petroleum gas (LPG) to cook. Micronucleus (MN) frequency was evaluated in buccal (BEC) and airway epithelial cells (AEC); DNA damage was examined by comet assay in peripheral blood lymphocytes (PBL); and expressions of gamma-H2AX, Mre11 and Ku70 proteins were localized in AEC and PBL by immunocytochemistry. Reactive oxygen species (ROS) generation in leukocytes was measured by flow cytometry, and the levels of superoxide dismutase (SOD) and total antioxidant status (TAS) in blood were measured by spectrophotometry. Real-time aerosol monitor was used to measure particulate pollutants in indoor air. Compared with controls, biomass users had increased frequencies of micronucleated cells in BEC (3.5 vs. 1.7, p<0.001) and AEC (4.54 vs. 1.86, p<0.001), and greater comet tail % DNA (18.6 vs. 11.7%, p<0.01), tail length (45.5 vs. 31.4mum, p<0.01) and olive tail moment (4.0 vs. 1.4, p<0.01) in PBL. Moreover, biomass users had more gamma-H2AX-positive nuclei in PBL (49.5 vs. 8.5%, p<0.01) and AEC (11.3 vs. 2.9%, p<0.01) along with higher expression of DNA repair proteins Mre11 and Ku70 in these cells, suggesting stimulation of DNA repair mechanism. Biomass users showed rise in ROS generation and depletion of SOD and TAS. Biomass-using households had 2-4 times more particulate matter with diameter less than 10 and 2.5mum in indoor air, and MN frequency and comet tail % DNA were positively associated with these pollutants after controlling potential confounders. Thus, chronic exposure to biomass smoke causes chromosomal and DNA damage and upregulation of DNA repair mechanism.

  15. Prediction of the air-water partition coefficient for perfluoro-2-methyl-3-pentanone using high-level Gaussian-4 composite theoretical methods.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2014-09-19

    The air-water partition coefficient (Kaw) of perfluoro-2-methyl-3-pentanone (PFMP) was estimated using the G4MP2/G4 levels of theory and the SMD solvation model. A suite of 31 fluorinated compounds was employed to calibrate the theoretical method. Excellent agreement between experimental and directly calculated Kaw values was obtained for the calibration compounds. The PCM solvation model was found to yield unsatisfactory Kaw estimates for fluorinated compounds at both levels of theory. The HENRYWIN Kaw estimation program also exhibited poor Kaw prediction performance on the training set. Based on the resulting regression equation for the calibration compounds, the G4MP2-SMD method constrained the estimated Kaw of PFMP to the range 5-8 × 10(-6) M atm(-1). The magnitude of this Kaw range indicates almost all PFMP released into the atmosphere or near the land-atmosphere interface will reside in the gas phase, with only minor quantities dissolved in the aqueous phase as the parent compound and/or its hydrate/hydrate conjugate base. Following discharge into aqueous systems not at equilibrium with the atmosphere, significant quantities of PFMP will be present as the dissolved parent compound and/or its hydrate/hydrate conjugate base.

  16. The composition of cosmic rays near the Bend (10 to the 15th power eV) from a study of muons in air showers at sea level

    NASA Technical Reports Server (NTRS)

    Goodman, J. A.; Gupta, S. C.; Freudenreich, H. T.; Sivaprasad, K.; Tonwar, S. C.; Yodh, G. B.; Ellsworth, R. W.; Goodman, M. C.; Bogert, M. C.; Burnstein, R.

    1985-01-01

    The distribution of muons near shower cores was studied at sea level at Fermilab using the E594 neutrino detector to sample the muon with E testing 3 GeV. These data are compared with detailed Monte Carlo simulations to derive conclusions about the composition of cosmic rays near the bend in the all particle spectrum. Monte Carlo simulations generating extensive air showers (EAS) with primary energy in excess of 50 TeV are described. Each shower record contains details of the electron lateral distribution and the muon and hadron lateral distributions as a function of energy, at the observation level of 100g/cm. The number of detected electrons and muons in each case was determined by a Poisson fluctuation of the number incident. The resultant predicted distribution of muons, electrons, the rate events are compared to those observed. Preliminary results on the rate favor a heavy primary dominated cosmic ray spectrum in energy range 50 to 1000 TeV.

  17. The impact of ground-level fireworks (13 km long) display on the air quality during the traditional Yanshui Lantern Festival in Taiwan.

    PubMed

    Chang, Shuenn-Chin; Lin, Ta-Hsiung; Young, Chea-Yuan; Lee, Chung-Te

    2011-01-01

    In this study, the concentrations of CO, non-methane hydrocarbons, NO(X), SO(2), benzene, toluene, ethylbenzene, xylene (BTEX), PM₁₀, and PM₂.₅ were continuously monitored before and after the fireworks display during the traditional Lantern Festival from March 2-7, 2007 in Yanshui Town, Taiwan. Major roads in Yanshui Town were surrounded by fireworks 13 km in length, with the display lasting for 45 min. More than 200 small firecracker towers popped up randomly in town, resulting in exceedingly inhomogeneous air quality until the end of display at 03:00 the next day, March 5. During the fireworks display, the hourly concentration of PM₁₀ and PM₂.₅ at Yanshui Primary School reached about 429 and 250 μg m⁻³, respectively, which is 10 times the normal level, and 6 s values even went as high as 1,046 and 842 μg m⁻³, respectively. Similarly, BTEX concentration went up to about five to 10 times its normal value during the fireworks display. As indicated by the distribution of submicron particle sizes, the number of particles with a diameter less than 100 nm increased abruptly during the event period. Metal components with concentrations of more than 10 times higher than the normal value at Yanshui Primary School were Sr, K, Ba, Pb, Al, Mg, and Cu, in sequence. Among water-soluble ions, the content of K( + ), Mg²( + ), and Cl( - ) increased the most, all of which were related to the materials used in the fireworks. The results of this study indicate that fireworks can cause an abrupt increase in the concentration of trace substances in the air within a short period. Although the risks of these trace substances on public health remain to be further assessed, the study results can be utilized in the management of folk events.

  18. Use of electronic cigarettes (e-cigarettes) impairs indoor air quality and increases FeNO levels of e-cigarette consumers.

    PubMed

    Schober, Wolfgang; Szendrei, Katalin; Matzen, Wolfgang; Osiander-Fuchs, Helga; Heitmann, Dieter; Schettgen, Thomas; Jörres, Rudolf A; Fromme, Hermann

    2014-07-01

    Despite the recent popularity of e-cigarettes, to date only limited data is available on their safety for both users and secondhand smokers. The present study reports a comprehensive inner and outer exposure assessment of e-cigarette emissions in terms of particulate matter (PM), particle number concentrations (PNC), volatile organic compounds (VOC), polycyclic aromatic hydrocarbons (PAH), carbonyls, and metals. In six vaping sessions nine volunteers consumed e-cigarettes with and without nicotine in a thoroughly ventilated room for two hours. We analyzed the levels of e-cigarette pollutants in indoor air and monitored effects on FeNO release and urinary metabolite profile of the subjects. For comparison, the components of the e-cigarette solutions (liquids) were additionally analyzed. During the vaping sessions substantial amounts of 1,2-propanediol, glycerine and nicotine were found in the gas-phase, as well as high concentrations of PM2.5 (mean 197 μg/m(3)). The concentration of putative carcinogenic PAH in indoor air increased by 20% to 147 ng/m(3), and aluminum showed a 2.4-fold increase. PNC ranged from 48,620 to 88,386 particles/cm(3) (median), with peaks at diameters 24-36 nm. FeNO increased in 7 of 9 individuals. The nicotine content of the liquids varied and was 1.2-fold higher than claimed by the manufacturer. Our data confirm that e-cigarettes are not emission-free and their pollutants could be of health concern for users and secondhand smokers. In particular, ultrafine particles formed from supersaturated 1,2-propanediol vapor can be deposited in the lung, and aerosolized nicotine seems capable of increasing the release of the inflammatory signaling molecule NO upon inhalation. In view of consumer safety, e-cigarettes and nicotine liquids should be officially regulated and labeled with appropriate warnings of potential health effects, particularly of toxicity risk in children.

  19. Biomarkers for exposure to ambient air pollution--comparison of carcinogen-DNA adduct levels with other exposure markers and markers for oxidative stress.

    PubMed

    Autrup, H; Daneshvar, B; Dragsted, L O; Gamborg, M; Hansen, M; Loft, S; Okkels, H; Nielsen, F; Nielsen, P S; Raffn, E; Wallin, H; Knudsen, L E

    1999-03-01

    Human exposure to genotoxic compounds present in ambient air has been studied using selected biomarkers in nonsmoking Danish bus drivers and postal workers. A large interindividual variation in biomarker levels was observed. Significantly higher levels of bulky carcinogen-DNA adducts (75.42 adducts/10(8) nucleotides) and of 2-amino-apidic semialdehyde (AAS) in plasma proteins (56.7 pmol/mg protein) were observed in bus drivers working in the central part of Copenhagen, Denmark. In contrast, significantly higher levels of AAS in hemoglobin (55.8 pmol/mg protein), malondialdehyde in plasma (0. 96 nmol/ml plasma), and polycyclic aromatic hydrocarbon (PAH)-albumin adduct (3.38 fmol/ microg albumin) were observed in the suburban group. The biomarker levels in postal workers were similar to the levels in suburban bus drivers. In the combined group of bus drivers and postal workers, negative correlations were observed between bulky carcinogen-DNA adduct and PAH-albumin levels (p = 0.005), and between DNA adduct and [gamma]-glutamyl semialdehyde (GGS) in hemoglobin (p = 0.11). Highly significant correlations were found between PAH-albumin adducts and AAS in plasma (p = 0.001) and GGS in hemoglobin (p = 0.001). Significant correlations were also observed between urinary 8-oxo-7, 8-dihydro-2'-deoxyguanosine and AAS in plasma (p = 0.001) and PAH-albumin adducts (p = 0.002). The influence of the glutatione S-transferase (GST) M1 deletion on the correlation between the biomarkers was studied in the combined group. A significant negative correlation was only observed between bulky carcinogen-DNA adducts and PAH-albumin adducts (p = 0.02) and between DNA adduct and urinary mutagenic activity (p = 0.02) in the GSTM1 null group, but not in the workers who were homozygotes or heterozygotes for GSTM1. Our results indicate that some of the selected biomarkers can be used to distinguish between high and low exposure to environmental genotoxins.

  20. Air Pollution

    MedlinePlus

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

  1. Precision liquid level sensor

    DOEpatents

    Field, M.E.; Sullivan, W.H.

    A precision liquid level sensor utilizes a balanced bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge.

  2. Geohydrologic units and water-level conditions in the Terrace alluvial aquifer and Paluxy Aquifer, May 1993 and February 1994, near Air Force Plant 4, Fort Worth area, Texas

    USGS Publications Warehouse

    Rivers, Glen A.; Baker, Ernest T.; Coplin, L.S.

    1996-01-01

    The terrace alluvial aquifer underlying Air Force Plant 4 and the adjacent Naval Air Station (formerly Carswell Air Force Base) in the Fort Worth area, Texas, is contaminated locally with organic and metal compounds. Residents south and west of Air Force Plant 4 and the Naval Air Station are concerned that contaminants might enter the underlying Paluxy aquifer, which provides water to the city of White Settlement, south of Air Force Plant 4, and to residents west of Air Force Plant 4. The U.S. Environmental Protection Agency has qualified Air Force Plant 4 for Superfund cleanup. The pertinent geologic units include -A~rom oldest to youngest the Glen Rose, Paluxy, and Walnut Formations, Goodland Limestone, and terrace alluvial deposits. Except for the Glen Rose Formation, all units crop out at or near Air Force Plant 4 and the Naval Air Station. The terrace alluvial deposits, which nearly everywhere form the land surface, range from 0 to about 60 feet thick. These deposits comprise a mostly unconsolidated mixture of gravel, sand, silt, and clay. Mudstone and sandstone of the Paluxy Formation crop out north, west, and southwest of Lake Worth and total between about 130 and about 175 feet thick. The terrace alluvial deposits and the Paluxy Formation comprise the terrace alluvial aquifer and the Paluxy aquifer, respectively. These aquifers are separated by the Goodland-Walnut confining unit, composed of the Goodland Limestone and (or) Walnut Formation. Below the Paluxy aquifer, the Glen Rose Formation forms the Glen Rose confining unit. Water-level measurements during May 1993 and February 1994 from wells in the terrace alluvial aquifer indicate that, regionally, ground water flows toward the east-southeast beneath Air Force Plant 4 and the Naval Air Station. Locally, water appears to flow outward from ground-water mounds maintained by the localized infiltration of precipitation and reportedly by leaking water pipes and sanitary and (or) storm sewer lines beneath the

  3. Well-construction, water-level, geophysical, and water-quality data for ground-water monitoring wells for Arnold Air Force Base, Tennessee

    USGS Publications Warehouse

    Hough, C.J.; Mahoney, E.N.; Robinson, J.A.

    1992-01-01

    Sixty-five wells were installed at 39 sites in the Arnold Air Force Base area in Coffee and Franklin Counties, Tennessee. The wells were installed to provide information on subsurface lithology, aquifer characteristics, ground-water levels, and ground-water quality. Well depths ranged from 11 to 384 feet. Water-quality samples were collected from 60 wells and analyzed for common inorganic ions, trace metals, and volatile organic compounds. The median dissolved-solids concentrations were 60 milligrams per liter in the shallow aquifer, 48 million gallons per liter in the Manchester aquifer, 1,235 milligrams per liter in the Fort Payne aquifer, and 1,712 milligrams per liter in the upper Central Basin aquifer. Caliper, temperature, natural gamma, electric, neutron porosity, gamma-gamma density, and acoustic velocity borehole-geophysical logs were obtained for the six deep wells completed below the Chattanooga Shale. Petrographic and modal analysis were performed on rock samples from each deep well. These six deep wells provide the first information in the study area on hydraulic head and water quality from below the Chattanooga Shale.

  4. Influence of avenue-trees on air quality at the urban neighborhood scale. Part II: traffic pollutant concentrations at pedestrian level.

    PubMed

    Gromke, Christof; Blocken, Bert

    2015-01-01

    Flow and dispersion of traffic-emitted pollutants were studied in a generic urban neighborhood for various avenue-tree layouts by employing 3D steady RANS simulations with the realizable k-ε turbulence model. In comparison to the tree-free situation quantitative and qualitative changes with flow reversal in the wind field were observed. Low to moderate increases (<13.2%) in the neighborhood-averaged pollutant concentration were found at pedestrian level. An approximately 1% increase in the neighborhood-averaged concentration was obtained with each percent of the street canyon volumes being occupied by vegetation for occupation fractions between 4 and 14%. The overall pattern of concentration changes relative to the tree-free situation was similar for all avenue-tree layouts. However, pronounced locally restricted decreases or increases in concentration (-87 to +1378%) occurred. The results indicate the necessity to account for existing or planned avenue-trees in neighborhood scaled is dispersion studies. Their consideration is prerequisite for reliable urban air quality assessment.

  5. A review of low-level air pollution and adverse effects on human health: implications for epidemiological studies and public policy

    PubMed Central

    Olmo, Neide Regina Simões; do Nascimento Saldiva, Paulo Hilário; Braga, Alfésio Luís Ferreira; Lin, Chin An; de Paula Santos, Ubiratan; Pereira, Luiz Alberto Amador

    2011-01-01

    The aim of this study was to review original scientific articles describing the relationship between atmospheric pollution and damage to human health. We also aimed to determine which of these studies mentioned public policy issues. Original articles relating to atmospheric pollution and human health published between 1995 and 2009 were retrieved from the PubMed database and analyzed. This study included only articles dealing with atmospheric pollutants resulting primarily from vehicle emissions. Three researchers were involved in the final selection of the studies, and the chosen articles were approved by at least two of the three researchers. Of the 84 non-Brazilian studies analyzed, 80 showed an association between atmospheric pollution and adverse effects on human health. Moreover, 66 showed evidence of adverse effects on human health, even at levels below the permitted emission standards. Three studies mentioned public policies aimed at changing emission standards. Similarly, the 29 selected Brazilian studies reported adverse associations with human health, and 27 showed evidence of adverse effects even at levels below the legally permitted emission standards. Of these studies, 16 mentioned public policies aimed at changing emission standards. Based on the Brazilian and non-Brazilian scientific studies that have been conducted, it can be concluded that, even under conditions that are compliant with Brazilian air quality standards, the concentration of atmospheric pollutants in Brazil can negatively affect human health. However, as little discussion of this topic has been generated, this finding demonstrates the need to incorporate epidemiological evidence into decisions regarding legal regulations and to discuss the public policy implications in epidemiological studies. PMID:21655765

  6. A review of low-level air pollution and adverse effects on human health: implications for epidemiological studies and public policy.

    PubMed

    Olmo, Neide Regina Simoes; Saldiva, Paulo Hilário do Nascimento; Braga, Alfésio Luís Ferreira; Lin, Chin An; Santos, Ubiratan de Paula; Pereira, Luiz Alberto Amador

    2011-01-01

    The aim of this study was to review original scientific articles describing the relationship between atmospheric pollution and damage to human health. We also aimed to determine which of these studies mentioned public policy issues. Original articles relating to atmospheric pollution and human health published between 1995 and 2009 were retrieved from the PubMed database and analyzed. This study included only articles dealing with atmospheric pollutants resulting primarily from vehicle emissions. Three researchers were involved in the final selection of the studies, and the chosen articles were approved by at least two of the three researchers. Of the 84 non-Brazilian studies analyzed, 80 showed an association between atmospheric pollution and adverse effects on human health. Moreover, 66 showed evidence of adverse effects on human health, even at levels below the permitted emission standards. Three studies mentioned public policies aimed at changing emission standards. Similarly, the 29 selected Brazilian studies reported adverse associations with human health, and 27 showed evidence of adverse effects even at levels below the legally permitted emission standards. Of these studies, 16 mentioned public policies aimed at changing emission standards. Based on the Brazilian and non-Brazilian scientific studies that have been conducted, it can be concluded that, even under conditions that are compliant with Brazilian air quality standards, the concentration of atmospheric pollutants in Brazil can negatively affect human health. However, as little discussion of this topic has been generated, this finding demonstrates the need to incorporate epidemiological evidence into decisions regarding legal regulations and to discuss the public policy implications in epidemiological studies.

  7. U.S. ENVIRONMENTAL PROTECTION AGENCY'S PM SUPERSITES PROGRAM - A MAJOR SUCCESSFUL COLLABORATIVE AIR QUALITY PROGRAM SUPPORTING STATES AND REGIONAL ORGANIZATIONS IN THEIR APPROACHES TO REDUCE PM LEVELS IN AIR ON URBAN AND REGIONAL SCALES

    EPA Science Inventory

    The U.S. Environmental Protection Agency's Particulate Matter (PM) Supersites Program (Program) is a nationwide air quality methods, measurement, modeling, and data analysis program initiated through cooperative agreements with leading universities in the United States. The Progr...

  8. Ground-water levels and water-quality data for wells in the Spring Creek area near Arnold Air Force Base, Tennessee, April and May 2000

    USGS Publications Warehouse

    Williams, Shannon D.; Aycock, Robert A.

    2001-01-01

    Arnold Air Force Base (AAFB) occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. Numerous site-specific ground-water contamination investigations have been conducted at designated solid waste management units (SWMU?s) at AAFB. Several synthetic volatile organic compounds (VOC?s), primarily chlorinated solvents, have been identified in groundwater samples collected from monitoring wells near SWMU 8 in the Spring Creek area. During April and May 2000, a study of the groundwater resources in the Spring Creek area was conducted to determine if VOC?s from AAFB have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. The study focused on sampling private wells located within the Spring Creek area that are used as a source of drinking water. Ground-water-flow directions were determined by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 35 private wells and 22 monitoring wells during the period of study. Depths to ground water were determined for 22 of the private wells and all 22 of the monitoring wells. The wells ranged in depth from 21 to 105 feet. Water-level altitudes ranged from 930 to 1,062 feet above sea level. Depths to water ranged from 8 to 83 feet below land surface. Water-quality samples were collected from 29 private wells which draw water from either gravel zones in the upper part of the Manchester aquifer, fractured bedrock in the lower part of the Manchester aquifer, or a combination of these two zones. Concentrations of 50 of the 55 VOC?s analyzed for were less than method detection limits. Chloroform, acetone, chloromethane, 2-butanone, and tetrachloroethylene were detected in concentrations exceeding the method detection limits. Only chloroform and acetone were detected in concentrations equal to or exceeding reporting limits. Chloroform was detected in a sample

  9. A COMPARISON OF GROUND-LEVEL AIR QUALITY DATA WITH NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION MONITORING STATIONS DATA IN SOUTH BRONX, NY. (R827351)

    EPA Science Inventory

    The South Bronx is a low-income, minority community in New York City. It has one of the highest asthma rates in the country, which community residents feel is related to poor air quality. Community residents also feel that the air quality data provided by the New York State D...

  10. Determining the Probability of Violating Upper-Level Wind Constraints for the Launch of Minuteman III Ballistic Missiles at Vandenberg Air Force Base

    NASA Technical Reports Server (NTRS)

    Shafer, Jaclyn A.; Brock, Tyler M.

    2012-01-01

    The 30th Operational Support Squadron Weather Flight (30 OSSWF) provides comprehensive weather services to the space program at Vandenberg Air Force Base (VAFB) in California. One of their responsibilities is to monitor upper-level winds to ensure safe launch operations of the Minuteman Ill ballistic missile. The 30 OSSWF tasked the Applied Meteorology Unit (AMU) to analyze VAFB sounding data with the goal of determining the probability of violating (PoV) their upper-level thresholds for wind speed and shear constraints specific to this launch vehicle, and to develop a tool that will calculate the PoV of each constraint on the day of launch. In order to calculate the probability of exceeding each constraint, the AMU collected and analyzed historical data from VAFB. The historical sounding data were retrieved from the National Oceanic and Atmospheric Administration Earth System Research Laboratory archive for the years 1994-2011 and then stratified into four sub-seasons: January-March, April-June, July-September, and October-December. The AMU determined the theoretical distributions that best fit the maximum wind speed and maximum wind shear datasets and applied this information when calculating the averages and standard deviations needed for the historical and real-time PoV calculations. In addition, the AMU included forecast sounding data from the Rapid Refresh model. This information provides further insight for the launch weather officers (LWOs) when determining if a wind constraint violation will occur over the next few hours on the day of launch. The AMU developed an interactive graphical user interface (GUI) in Microsoft Excel using Visual Basic for Applications. The GUI displays the critical sounding data easily and quickly for LWOs on day of launch. This tool will replace the existing one used by the 30 OSSWF, assist the LWOs in determining the probability of exceeding specific wind threshold values, and help to improve the overall upper winds forecast for

  11. Evaluation of the Mesoscale Meteorological Model (MM5)-Community Multi-Scale Air Quality Model (CMAQ) performance in hindcast and forecast of ground-level ozone.

    PubMed

    Nghiem, Le Hoang; Kim Oanh, Nguyen Thi

    2008-10-01

    This paper presents the first attempt to apply the Mesoscale Meteorological Model (MM5)-Community Multi-Scale Air Quality Model (CMAQ) model system to simulate ground-level ozone (O3) over the continental Southeast Asia (CSEA) region for both hindcast and forecast purposes. Hindcast simulation was done over the CSEA domain for two historical O3 episodes, January 26-29, 2004 (January episode, northeast monsoon) and March 24-26, 2004 (March episode, southwest monsoon). Experimental forecast was done for next-day hourly O3 during January 2006 over the central part of Thailand (CENTHAI). Available data from 20 ambient monitoring stations in Thailand and 3 stations in Ho Chi Minh City, Vietnam, were used for the episode analysis and for the model performance evaluation. The year 2000 anthropogenic emission inventory prepared by the Center for Global and Regional Environmental Research at the University of Iowa was projected to the simulation year on the basis of the regional average economic growth rate. Hourly emission in urban areas was prepared using ambient carbon monoxide concentration as a surrogate for the emission intensity. Biogenic emissions were estimated based on data from the Global Emissions Inventory Activity. Hindcast simulations (CSEA) were performed with 0.5 degree x 0.5 degree resolution, whereas forecast simulations (CENTHAI) were done with 0.1 degree x 0.1 degree hourly emission input data. MM5-CMAQ model system performance during the selected episodes satisfactorily met U.S. Environmental Protection Agency criteria for O3 for most simulated days. The experiment forecast for next-day hourly O3 in January 2006 yielded promising results. Modeled plumes of ozone in both hindcast and forecast cases agreed with the main wind fields and extended over considerable downwind distances from large urban areas.

  12. Determination of benzo[a]pyrene levels in ambient air and the source of polycyclic aromatic hydrocarbons using a diagnostic ratio method in Ghana.

    PubMed

    Bortey-Sam, Nesta; Akoto, Osei; Ikenaka, Yoshinori; Nakayama, Shouta M M; Ishizuka, Mayumi

    2013-02-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants produced from incomplete combustion of fuel or vegetation fires. Their presence in air deserves attention because they can produce carcinogenic and mutagenic effects. As an industrialized and economically significant city in Ghana, Kumasi has been subject to heavy anthropogenic influences due to rapid economic development and urbanization leading to a greater fuel combustion rate. Airborne particulate samples were collected on filters using a Sibata air sampler and analyzed by gas chromatography-mass spectrometry (GC-MS). Our results indicated that air from the city center can be classified as highly polluted with benzo[a] pyrene (B[a]P). The diagnostic ratios of the results showed that PAHs in the air samples were mainly from fuel combustion.

  13. Measurement of sub-parts-per-billion levels of carbonyl compounds in marine air by a simple cartridge trapping procedure followed by liquid chromatography

    SciTech Connect

    Xianliang, Zhou; Mopper, K. )

    1990-10-01

    Carbonyl compounds in clean marine air were trapped onto 2,4-dinitrophenylhydrazine- (DNPH-) coated cartridges, and their hydrazone derivatives were separated by HPLC and detected by UV absorbance. More than 20 carbonyl compounds were isolated from marine air with >92% collection efficiency. The technique employs a highly effective reagent purification procedure, which results in much lower blanks compared to previously reported trapping techniques for carbonyl compounds. Blanks were routinely <0.07 ppb for formaldehyde and acetone and <0.02 ppb for the others. Humidity and reactive gases have no detectable effect on collection efficiencies. Carbonyl-DNPH derivatives eluted from the cartridges are stable in acetonitrile for at least 2 weeks, which facilitates field studies. Several previously undetected unknown carbonyl compounds were found in marine air by this technique. Typical results for open ocean and coastal marine air are shown.

  14. Application of an Integrated Assessment Model with state-level resolution for examining strategies for addressing air, climate and energy goals

    EPA Science Inventory

    The Global Climate Assessment Model (GCAM) is a global integrated assessment model used for exploring future scenarios and examining strategies that address air pollution, climate change, and energy goals. GCAM includes technology-rich representations of the energy, transportati...

  15. Impact of Saharan dust events on radionuclide levels in Monaco air and in the water column of the northwest Mediterranean Sea.

    PubMed

    Pham, Mai Khanh; Chamizo, Elena; Mas Balbuena, José Luis; Miquel, Juan-Carlos; Martín, Jacobo; Osvath, Iolanda; Povinec, Pavel P

    2017-01-01

    Characterization of atmospheric aerosols collected in Monaco (2004-2008) and in sediment traps at 200 m and 1000 m water depths at the DYFAMED (Dynamics of Atmospheric Fluxes in the Mediterranean Sea) station (2004) was carried out to improve our understanding of the impact of Saharan dust on ground-level air and on the water column. Activity concentrations of natural ((210)Pb, (210)Po, uranium and radium isotopes) and anthropogenic ((137)Cs, (239)Pu, (240)Pu, and (239+240)Pu) radionuclides and their isotopic ratios confirmed a Saharan impact on the investigated samples. In association with a large particulate matter deposition event in Monaco on 20 February 2004, the (137)Cs (∼40 Bq kg(-1)) and (239+240)Pu (∼1 Bq kg(-1)) activities were almost a factor of two higher than other Saharan deposition dust events. This single-day particle flux represented 72% of the annual atmospheric deposition in Monaco. The annual deposition of Saharan dust on the sea was 232-407 mBq m(-2) for (137)Cs and 6.8-9.8 mBq m(-2) for (239+240)Pu and contributed significantly (28-37% for (137)Cs and 34-45% for (239+240)Pu) to the total annual atmospheric input to the northwest Mediterranean Sea. The (137)Cs/(239+240)Pu activity ratios in dust samples collected during different Saharan dust events confirmed their global fallout origin or mixing with local re-suspended soil particles. In the sediment trap samples the (137)Cs activity varied by a factor of two, while the (239+240)Pu activity was constant, confirming the different behaviors of Cs (dissolved) and Pu (particle reactive) in the water column. The (137)Cs and (239+240)Pu activities of sinking particles during the period of the highest mass flux collected in 20 February 2004 at the 200 m and 1000 m water depths represented about 10% and 15%, respectively, of annual deposition from Saharan dust events.

  16. Hydrogeologic, water-level, and water-quality data from monitoring wells at the US Marine Corps Air Station, Cherry Point, North Carolina

    USGS Publications Warehouse

    Murray, L.C.; Keoughan, K.M.

    1990-01-01

    Unlined hazardous-waste disposal sites at the U.S. Marine Corps Air Station, Cherry Point, North Carolina, are located near drinking-water supply wells that tap the Castle Hayne aquifer. Hydrogeologic and water-quality data were collected near 2 of these sites from 12 monitoring wells installed in May through June 1987. Near the northernmost landfill site, differences in hydraulic head between the surficial, intermediate Yorktown, and Castle Hayne aquifers indicate a potential for migration of contaminants downward into the intermediate Yorktown and Castle Hayne aquifers. Movement would be impeded, however, by two confining units of silty sand to sandy clay that separate these aquifers. Geophysical and lithologic data show the upper confining unit to be approximately 26 feet thick near this landfill. Near the southernmost landfill, these confining units are thin and discontinuous in an area that coincides with the location of a buried paleochannel. Static water-level data collected in this area indicate that both the Castle Hayne and Yorktown aquifers discharge into the surficial aquifer, minimizing the potential for downward contaminant movement. Ground water in the surficial aquifer at both landfills moves laterally away from nearby drinking-water supply wells and toward Slocum Creek, a tributary of the Neuse River. Concentrations of organic compounds and trace inorganic constituents included on the U.S. Environmental Protection Agency?s list of priority pollutants were determined for water samples from the surficial and Yorktown aquifers. High concentrations of two purgeable organic compounds, trichloroethylene and 1,2-dichloroethene (4,600 and 4,800 micrograms per liter, respectively), were detected in water samples collected from the surficial aquifer near the southernmost landfill; much smaller concentrations of trichloroethylene and 1,2-dichloroethene were detected in samples from wells in the Yorktown aquifer (up to 16 and 12 micrograms per liter

  17. Meeting 2006, outdoor noise directive (OND) noise levels for a diesel engine driven air compressor: A case study in noise reduction

    NASA Astrophysics Data System (ADS)

    Rowe, David F.

    2005-09-01

    In January 2006, the noise limits for many products in the European Union will drop by 2-3 dBA, as directed by 2000/14/EC ``Noise Emission in the Environment by Equipment Used Outdoors,'' commonly called the ``Outdoor Noise Directive,'' or ``OND.'' Air compressors are among the products addressed by this directive. At Ingersoll-Rand, significant effort has been directed at meeting the challenge of reducing noise on a variety of diesel engine driven air compressor platforms, ranging from 15 to 350 kW diesel engine power ratings. This paper presents a case study of the noise reduction on a 750 cfm (21 m3/min) air compressor operating at 300 psig (21 bar), to meet the 2006 OND noise limit of 100 LwA.

  18. Ozone, Air Quality, and Asthma (For Parents)

    MedlinePlus

    ... How Poor Air Quality Affects People With Asthma Air pollution is a problem for everyone — not just people ... asthma. Studies have shown that high levels of air pollution can be associated with decreased lung function and ...

  19. Bad Air For Children

    ERIC Educational Resources Information Center

    Kane, Dorothy Noyes

    1976-01-01

    Children are especially sensitive to air pollution and consequences to them maybe of longer duration than to adults. The effects of low-level pollution on children are the concern of this article. The need for research on the threat of air pollution to childrens' health is emphasized. (BT)

  20. Discriminatory Air Pollution

    ERIC Educational Resources Information Center

    McCaull, Julian

    1976-01-01

    Described are the patterns of air pollution in certain large urban areas. Persons in poverty, in occupations below the management or professional level, in low-rent districts, and in black population are most heavily exposed to air pollution. Pollution paradoxically is largely produced by high energy consuming middle-and upper-class households.…

  1. Hearing Levels of Noise-Exposed U.S. Air Force Personnel Compared to Those in the Total U. S. Population

    DTIC Science & Technology

    1976-09-01

    the U.S. Public Health Service and the U.S. Air K • J Force use TDH -39 earphones with MX-41/AR cushions. In Table 4, the distribution of hearing...Association, 1951. 6. Cox, J. R., Jr., and R. C. Bilger. Suggestion relative to the standardi- zation of loudness-balance data for the telephonics TDH

  2. The Correlation between Sex, Age, Educational Background, and Hours of Service on Vigilance Level of ATC Officers in Air Nav Surabaya, Indonesia

    ERIC Educational Resources Information Center

    Saleh, Lalu Muhammad; Suwandi, Tjipto; Hamidah

    2016-01-01

    The vigilance of an Air Traffic Control (ATC) officer determines aviation safety. The number of aviation accidents tends to be increasing in recent years. Aviation accidents may be caused by human errors (i.e. errors made by pilot or ATC officer) or unsafe work condition. Sex, age, educational background, and hours of service might affect…

  3. Impacts of Hazardous Air Pollutants Emitted from Phosphate Fertilizer Production Plants on their Ambient Concentration Levels in the Tampa Bay Area

    EPA Science Inventory

    The concentrations and distribution of Hazardous Air Pollutants (HAPs) metals emitted from four phosphate fertilizer plants in Central Florida, as well as their environmental and health impacts, were assessed. The dominant HAP metals emitted from the stacks of these plants were M...

  4. Concepts of a Higher Hierarchical Level Require More Dual Situated Learning Events for Conceptual Change: A Study of Air Pressure and Buoyancy.

    ERIC Educational Resources Information Center

    She, Hsiao-Ching

    2002-01-01

    Examines the process of students' conceptual changes with regard to air pressure and buoyancy as a result of teaching with the dual situated learning model. Uses a model designed according to the students' ontological viewpoint on science concepts as well as the nature of these concepts. (Contains 40 references.) (Author/YDS)

  5. Motor transport related harmful PM2.5 and PM10: from onroad measurements to the modelling of air pollution by neural network approach on street and urban level

    NASA Astrophysics Data System (ADS)

    Lozhkina, O.; Lozhkin, V.; Nevmerzhitsky, N.; Tarkhov, D.; Vasilyev, A.

    2016-11-01

    The level of PM10 and PM2.5 concentrations in the air on seven roads in St. Petersburg, Russia, were investigated using gravimetry and nephelometry measurement techniques in 2013-2015. The effects of meteorological conditions (temperature, relative humidity, wind direction, and speed) and the intensity of traffic flows on the results of the measurements were also evaluated. On the base of the measurements, there was developed a neural network modelling approach that allowed to quantify exhaust / non-exhaust PM10 and PM 2.5 emissions and carry out numerical investigations of air pollution by transport related PM2.5 and PM10 on street and urban level in St. Petersburg.

  6. Air Traffic Network Project

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The high level requirement of the Air Traffic Network (ATN) project is to provide a mechanism for evaluating the impact of router scheduling modifications on a networks efficiency, without implementing the modifications in the live network.

  7. In pursuit of clean air: a data book of problems and strategies at the state level. Volume 3: Federal Regions IV and VI

    SciTech Connect

    Garvey, D.B.; Streets, D.G.

    1980-02-01

    This is the third volume of a five-volume report, designed to provide useful information for policy analysis in the Department of Energy, especially for the examination of possible areas of conflict between the implementation of a national energy policy calling for the increased use of coal and the pursuit of clean air. Information is presented for each state in Federal Regions IV and VI under the following section headings: state title page (includes a summary of air quality data); revised state implementation plan outline; maps of nonattainment areas, as designated; Storage and Retrieval of Aerometric Data (SAROAD); SAROAD data maps; power plant data; power plant maps; and county maps. States in Federal Region IV include: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee. Those in Federal Region VI include: Arkansas, Louisiana, New Mexico, Oklahoma, and Texas. (JGB)

  8. Longitudinal development of muons in large air showers studies from the arrival time distributions measured at 900m above sea level

    NASA Technical Reports Server (NTRS)

    Kakimoto, F.; Tsuchimoto, I.; Enoki, T.; Suga, K.; Nishi, K.

    1985-01-01

    The arrival time distributions of muons with energies above 1.0GeV and 0.5GeV have been measured in the Akeno air-shower array to study the longitudinal development of muons in air showers with primary energies in the range 10 to the 17th power to 10 to the 18th power ev. The average rise times of muons with energies above 1.0GeV at large core distances are consistent with those expected from very high multiplicity models and, on the contrary, with those expected from the low multiplicity models at small core distances. This implies that the longitudinal development at atmospheric depth smaller than 500 cm square is very fast and that at larger atmospheric depths is rather slow.

  9. Requirements Definition for Force Level Command and Control in the Tactical Air Control System: An Evolutionary Approach Toward Meeting Near Term and Future Operational Needs.

    DTIC Science & Technology

    1985-01-01

    numerous major exercises, such as WINTEX- CIMEX , REFORGER, CRESTED EAGLE, and BRIGHT STAR. USAFE is now actively planning an evolutionary approach toward C2...during WINTEX- CIMEX 85, we have been investigating a number of approaches to enhancing joint air-ground operations and providing a means for better...throughout the ground battle elements. The USAREUR Distributed Decision Aid System (UD[1AS) was initially deployed in Exercise WINTEX- CIMEX 84. During

  10. Photochemical model evaluation of the ground-level ozone impacts on ambient air quality and vegetation health in the Alberta oil sands region: Using present and future emission scenarios

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, Krish; Cho, Sunny; Morris, Ralph; Spink, David; Jung, Jaegun; Pauls, Ron; Duffett, Katherine

    2016-09-01

    One of the potential environmental issues associated with oil sands development is increased ozone formation resulting from NOX and volatile organic compound emissions from bitumen extraction, processing and upgrading. To manage this issue in the Athabasca Oil Sands Region (AOSR) in northeast Alberta, a regional multi-stakeholder group, the Cumulative Environmental Management Association (CEMA), developed an Ozone Management Framework that includes a modelling based assessment component. In this paper, we describe how the Community Multi-scale Air Quality (CMAQ) model was applied to assess potential ground-level ozone formation and impacts on ambient air quality and vegetation health for three different ozone precursor cases in the AOSR. Statistical analysis methods were applied, and the CMAQ performance results met the U.S. EPA model performance goal at all sites. The modelled 4th highest daily maximum 8-h average ozone concentrations in the base and two future year scenarios did not exceed the Canada-wide standard of 65 ppb or the newer Canadian Ambient Air Quality Standards of 63 ppb in 2015 and 62 ppb in 2020. Modelled maximum 1-h ozone concentrations in the study were well below the Alberta Ambient Air Quality Objective of 82 ppb in all three cases. Several ozone vegetation exposure metrics were also evaluated to investigate the potential impact of ground-level ozone on vegetation. The chronic 3-months SUM60 exposure metric is within the CEMA baseline range (0-2000 ppb-hr) everywhere in the AOSR. The AOT40 ozone exposure metric predicted by CMAQ did not exceed the United Nations Economic Commission for Europe (UN/ECE) threshold of concern of 3000 ppb-hr in any of the cases but is just below the threshold in high-end future emissions scenario. In all three emission scenarios, the CMAQ predicted W126 ozone exposure metric is within the CEMA baseline threshold of 4000 ppb-hr. This study outlines the use of photochemical modelling of the impact of an industry (oil

  11. Air Quality Index (AQI) -- A Guide to Air Quality and Your Health

    MedlinePlus

    ... the AQI value, the greater the level of air pollution and the greater the health concern. For example, ... to 50. Air quality is considered satisfactory, and air pollution poses little or no risk. "Moderate" AQI is ...

  12. [A chromatographic method of determining the levels of organic solvents in the air, the components of the offset lacquer LO-2].

    PubMed

    Dobecki, M; Czerczak, S

    1987-01-01

    A gas chromatographic method was worked out to determine the mixture of ethyl acetate, toluene, buthyl acetate, p,m-xylene, o-xylene and ethyl ethylene glycol vapours. These solvents are used as some components of offset lacquer LO-2. Optimum separation conditions were achieved on 3-metre SS column filled with 10% FFAP on Chormosorb W AW DMCS 80-100 mesh. Air samples were collected on activated charcoal placed in glass tubes. The components tested were desorbed from the sorbent material by 10% acetone solution in CS2. The method enables to determine the concentrations of each compound, corresponding to one fifth of their TLVs.

  13. The Glass Ceiling Effect and Its Impact on Mid-Level Female Military Officer Career Progression in the United States Marine Corps and Air Force

    DTIC Science & Technology

    2004-03-01

    society . The Defense Department assured the committee that there would be no attempt to remove restrictions on the kind of military duties women ...lower than the men. Nevertheless more women are entering the Air 0 10 20 30 40 50 60 70 80 Pe rc en t Ac ad em y RO TC Di rec t A pp t OC S / OT S Ot he...Stay. Womens ’ Enews. Retrieved from http://www.womensenews.org Rostker, B., Thie, H., Lacy, J. L., Kawata, J. H., & Purnell, S . W.(1993). The

  14. Correction factors for the NMi free-air ionization chamber for medium-energy x-rays calculated with the Monte Carlo method.

    PubMed

    Grimbergen, T W; van Dijk, E; de Vries, W

    1998-11-01

    A new method is described for the determination of x-ray quality dependent correction factors for free-air ionization chambers. The method is based on weighting correction factors for mono-energetic photons, which are calculated using the Monte Carlo method, with measured air kerma spectra. With this method, correction factors for electron loss, scatter inside the chamber and transmission through the diaphragm and front wall have been calculated for the NMi free-air chamber for medium-energy x-rays for a wide range of x-ray qualities in use at NMi. The newly obtained correction factors were compared with the values in use at present, which are based on interpolation of experimental data for a specific set of x-ray qualities. For x-ray qualities which are similar to this specific set, the agreement between the correction factors determined with the new method and those based on the experimental data is better than 0.1%, except for heavily filtered x-rays generated at 250 kV. For x-ray qualities dissimilar to the specific set, differences up to 0.4% exist, which can be explained by uncertainties in the interpolation procedure of the experimental data. Since the new method does not depend on experimental data for a specific set of x-ray qualities, the new method allows for a more flexible use of the free-air chamber as a primary standard for air kerma for any x-ray quality in the medium-energy x-ray range.

  15. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

  16. Air Pollution

    MedlinePlus

    ... of Climate Change on Children's Health: Session Two: Air Quality Impacts MODERATOR: Susan Anenberg, EPA Meredith McCormack, Johns ... University • Effects of Climate Change on Children’s Health: Air Quality Impacts Frederica Perera, Columbia University • Air quality Impacts ...

  17. Chemistry of snow cover and acidic snowfall during a season with a high level of air pollution on the Hans Glacier, Spitsbergen

    NASA Astrophysics Data System (ADS)

    Nawrot, Adam P.; Migała, Krzysztof; Luks, Bartłomiej; Pakszys, Paulina; Głowacki, Piotr

    2016-09-01

    The central Arctic is within the range of air pollution transported from industrial areas of Eurasia and North America. A poor network of weather stations means that there is limited information available about air quality and contaminant deposition in the Arctic environment. For this reason seasonal snow cover is an important source of information. Chemical properties of precipitation, snow cover and fresh snow were monitored at the Hornsund Polish Polar Station (Spitsbergen) and in the altitude profile of the Hans Glacier. Meteorological data from the coast and the glacier helped to examine in detail the impact of atmospheric processes on snow cover contamination. The episode with extremely acidic precipitation was recognized in snow cover analysed in spring 2006. The source area of pollution and type of synoptic situation which enhanced transfer of pollution to the European Arctic were identified. Changes in snow chemistry in the altitude profile demonstrated the impact of the atmospheric boundary layer on chemical properties of precipitation and snow cover. Non-sea salt SO2 emissions and the role of nitrate in acidification should be considered a serious threat to the Arctic environment.

  18. Molecular typing of Treponema pallidum isolates from Buenos Aires, Argentina: Frequent Nichols-like isolates and low levels of macrolide resistance.

    PubMed

    Gallo Vaulet, Lucía; Grillová, Linda; Mikalová, Lenka; Casco, Ricardo; Rodríguez Fermepin, Marcelo; Pando, María A; Šmajs, David

    2017-01-01

    A total of 54 clinical samples, including genital lesion swabs, whole blood and cerebrospinal fluid from patients diagnosed with syphilis were collected in 2006 and in 2013 in Buenos Aires, Argentina. Treponemal DNA was detected in 43 of the analyzed samples (79.6%) and further analyzed using Sequencing-based molecular typing (SBMT) and Enhanced CDC-typing (ECDCT). By SBMT, 10 different Treponema pallidum subsp. pallidum (TPA) genotypes were found, of which six were related to the TPA SS14 strain, and four to the TPA Nichols strain. The 23S rRNA gene was amplified in samples isolated from 42 patients, and in six of them (14.3%), either the A2058G (four patients, 9.5%) or the A2059G (two patients, 4.8%) mutations were found. In addition to Taiwan, Madagascar and Peru, Argentina is another country where the prevalence of Nichols-like isolates (26.8%) is greater than 10%.

  19. On Development and Characterisation of a Mobile and Metrologically Traceable Reference Gas Generator for Ammonia and Other Reactive Species in Ambient Air Levels

    NASA Astrophysics Data System (ADS)

    Leuenberger, Daiana; Pascale, Céline; Guillevic, Myriam; Ackermann, Andreas; Niederhauser, Bernhard

    2016-04-01

    Ammonia NH3 in the atmosphere is the major precursor for neutralising atmospheric acids and is thus affecting not only the long-range transport of sulphur dioxide and nitrogen oxides but also stabilies secondary particulate matter. These aerosols have negative impacts on air quality and human health. Moreover, they negatively affect terrestrial ecosystems after deposition. NH3 has been included in the air quality monitoring networks and emission reduction directives of European nations. Atmospheric concentrations are in the order of 0.5-500 nmol/mol. However, the lowest substance amount fraction of available certified reference material (CRM) is 30 μmol/mol. The EMRP JRP ENV55 MetNH3 aims at overcoming this discrepancy by assessing and developing novel approaches for the production of CRM and measurement methods. The Federal Institute of Metrology METAS has developed a mobile and metrologically traceable reference gas generator for reactive gases (ReGaS1). This device is based on the specific temperature dependent permeation of the reference substance through a membrane into a flow of carrier gas and subsequent dynamic dilution to desired amount fractions. The characteristics of individual components lead to the uncertainty estimation for the generated NH3 gas mixture according to GUM, which is aimed to be <3 %. Here we present insights into the development of said instrument and results of the first performance tests. Moreover, we include results of the study on adsorption/desorption effects in dry as well as humidified matrix gas into the discussion on the generation of reference gas mixtures.

  20. ASSESSMENT OF THE IMPACTS OF GLOBAL CHANGE ON REGIONAL U.S. AIR QUALITY: A SYNTHESIS OF CLIMATE CHANGE IMPACTS ON GROUND-LEVEL OZONE (AN INTERIM REPORT OF THE U.S. EPA GLOBAL CHANGE RESEARCH PROGRAM)

    EPA Science Inventory

    The Air Quality Assessment Final Report is intended for managers and scientists working on air quality to provide them with information on the potential effects of climate change on regional air quality in the United States.

  1. Application of low-cost Gallium Arsenide light-emitting-diodes as kerma dosemeter and fluence monitor for high-energy neutrons.

    PubMed

    Mukherjee, B; Simrock, S; Khachan, J; Rybka, D; Romaniuk, R

    2007-01-01

    Displacement damage (DD) caused by fast neutrons in unbiased Gallium Arsenide (GaAs) light emitting diodes (LED) resulted in a reduction of the light output. On the other hand, a similar type of LED irradiated with gamma rays from a (60)Co source up to a dose level in excess of 1.0 kGy (1.0 x 10(5) rad) was found to show no significant drop of the light emission. This phenomenon was used to develop a low cost passive fluence monitor and kinetic energy released per unit mass dosemeter for accelerator-produced neutrons. These LED-dosemeters were used to assess the integrated fluence of photoneutrons, which were contaminated with a strong bremsstrahlung gamma-background generated by the 730 MeV superconducting electron linac driving the free electron laser in Hamburg (FLASH) at Deutsches Elektronen-Synchrotron. The applications of GaAs LED as a routine neutron fluence monitor and DD precursor for the electronic components located in high-energy accelerator environment are highlighted.

  2. Identifying Best Bet Entry-Level Selection Measures for US Air Force Remotely Piloted Aircraft (RPA) Pilot and Sensor Operator (SO) Occupations

    DTIC Science & Technology

    2011-12-01

    between Male and Female Enlisted Basic Trainees .................................................................................................... 45...Table 8. Section A: Rating Your Ideal Job – Scale-Level Comparison between Male and Female Enlisted Basic Trainees...between Male and Female Officer Trainees (OTS) .................................................................................................... 49

  3. Air Policing

    DTIC Science & Technology

    2009-05-01

    Iraq. To provide a background for understanding why Britain commenced the policy of air policing, this paper begins with a review of contemporary...7 Omissi, Air Power, XV. 8 policing actions or the pushing home of advantages gained by the air.” Within the context of this paper , the...control operations, and therefore within the context of this paper , the term coercive airpower refers to the threat of harming a population or the threat

  4. Air Force standards for nickel hydrogen battery

    NASA Technical Reports Server (NTRS)

    Hwang, Warren; Milden, Martin

    1994-01-01

    The topics discussed are presented in viewgraph form and include Air Force nickel hydrogen standardization goals, philosophy, project outline, cell level standardization, battery level standardization, and schedule.

  5. Emission sources sensitivity study for ground-level ozone and PM2.5 due to oil sands development using air quality modeling system: Part I- model evaluation for current year base case simulation

    NASA Astrophysics Data System (ADS)

    Cho, Sunny; McEachern, Preston; Morris, Ralph; Shah, Tejas; Johnson, Jeremiah; Nopmongcol, Uarporn

    2012-08-01

    The Community Multiscale Air Quality (CMAQ) and the Sparse Matrix Operator Kernel Emissions (SMOKE) modeling systems were used to simulate emissions and air quality in North Eastern Alberta where a rapid rise in oil sands development has caused air quality concerns over the last decade. The models were run on a 36/12/4 km domain for the four month period of May through August 2002. A model performance evaluation was conducted by comparing the CMAQ model estimates against ambient air quality measurements. In the Alberta oil sands region, the model tended to achieve or nearly achieve ozone model performance goals, albeit with an underestimation bias. The magnitudes of the observed PM2.5 concentrations were matched by the modeling system, except when the observed PM2.5 concentrations were influenced by emissions from forest fires in which case the model underestimated the observed PM2.5 concentrations. The CMAQ-estimated 4th highest daily maximum 8-hour ozone concentrations in the oil sands region were below the 65 ppb Canada Wide Standard (CWS) as well as the 58 ppb Alberta Management Plan Trigger Level. The highest estimated ozone concentrations occurred near the oil sands development area just north of Fort McMurray with values approaching, but below, the 58 ppb Management Plan Trigger Level; estimated ozone concentrations are much lower in the farther northern portions of the oil sands region. The acute (i.e., maximum 3-day value) SUM60 vegetative ozone exposure metric was mostly less than 100 ppb h, which is below the threshold of concern for crops. However, just north of Fort McMurray there were small areas where the acute SUM60 metric exceeded the 500-700 ppb h threshold of concern for crops with maximum values in plumes from sources in the oil sands mine area of ˜900 ppb h. The maximum chronic (three-month average) SUM60 ozone exposure metric was below the thresholds of concern. The CMAQ-estimated maximum 98th percentile 24-hour average PM2.5 concentration

  6. Molecular typing of Treponema pallidum isolates from Buenos Aires, Argentina: Frequent Nichols-like isolates and low levels of macrolide resistance

    PubMed Central

    Gallo Vaulet, Lucía; Grillová, Linda; Mikalová, Lenka; Casco, Ricardo; Rodríguez Fermepin, Marcelo; Pando, María A.; Šmajs, David

    2017-01-01

    A total of 54 clinical samples, including genital lesion swabs, whole blood and cerebrospinal fluid from patients diagnosed with syphilis were collected in 2006 and in 2013 in Buenos Aires, Argentina. Treponemal DNA was detected in 43 of the analyzed samples (79.6%) and further analyzed using Sequencing-based molecular typing (SBMT) and Enhanced CDC-typing (ECDCT). By SBMT, 10 different Treponema pallidum subsp. pallidum (TPA) genotypes were found, of which six were related to the TPA SS14 strain, and four to the TPA Nichols strain. The 23S rRNA gene was amplified in samples isolated from 42 patients, and in six of them (14.3%), either the A2058G (four patients, 9.5%) or the A2059G (two patients, 4.8%) mutations were found. In addition to Taiwan, Madagascar and Peru, Argentina is another country where the prevalence of Nichols-like isolates (26.8%) is greater than 10%. PMID:28235102

  7. Precision liquid level sensor

    DOEpatents

    Field, M.E.; Sullivan, W.H.

    1985-01-29

    A precision liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge. 2 figs.

  8. Precision liquid level sensor

    DOEpatents

    Field, Michael E.; Sullivan, William H.

    1985-01-01

    A precision liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge.

  9. Incorporating Air Pollutant Emission Factors and State-Level Controls and Energy Policies within the GCAM-USA Integrated Assessment Model

    EPA Science Inventory

    The Global Change Assessment Model (GCAM) is an integrated assessment model that links representations of the economy, energy sector, land use, and climate within an integrated modeling environment. GCAM-USA, which is an extension of GCAM, provides U.S. state-level resolution wit...

  10. Grade Inflation: Reality or Myth? Student Preparation Level vs. Grades at Brigham Young University, 1975-1994. AIR 1997 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Olsen, Danny R.

    This study was designed to investigate the extent to which grade inflation has existed at Brigham Young University (BYU) after accounting for increased preparation levels of entering students over time. Analyses were conducted for the university at large and individual colleges. The study first developed a model to forecast student grade point…

  11. Air transport

    NASA Technical Reports Server (NTRS)

    Page, F Handley

    1924-01-01

    I purpose (sic) in this paper to deal with the development in air transport which has taken place since civil aviation between England and the Continent first started at the end of August 1919. A great deal of attention has been paid in the press to air services of the future, to the detriment of the consideration of results obtained up to the present.

  12. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  13. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  14. AIR Model Preflight Analysis

    NASA Technical Reports Server (NTRS)

    Tai, H.; Wilson, J. W.; Maiden, D. L.

    2003-01-01

    The atmospheric ionizing radiation (AIR) ER-2 preflight analysis, one of the first attempts to obtain a relatively complete measurement set of the high-altitude radiation level environment, is described in this paper. The primary thrust is to characterize the atmospheric radiation and to define dose levels at high-altitude flight. A secondary thrust is to develop and validate dosimetric techniques and monitoring devices for protecting aircrews. With a few chosen routes, we can measure the experimental results and validate the AIR model predictions. Eventually, as more measurements are made, we gain more understanding about the hazardous radiation environment and acquire more confidence in the prediction models.

  15. Well-construction, water-level, and water-quality data for ground-water monitoring wells for the J4 hydrogeologic study, Arnold Air Force Base, Tennessee

    USGS Publications Warehouse

    Haugh, C.J.

    1996-01-01

    Between December 1993 and March 1994, 27 wells were installed at 12 sites near the J4 test cell at Arnold Engineering Development Center in Coffee County, Tennessee. The wells ranged from 28 to 289 feet deep and were installed to provide information on subsurface lithology, aquifer characteristics, ground-water levels, and ground-water quality. This information will be used to help understand the effects of dewatering operations at the J4 test cell on the local ground-water-flow system. The J4 test cell, extending approximately 250 feet below land surface, is used in the testing of rocket motors. Ground water must be pumped continuously from around the test cell to keep it structurally intact. The amount of water discharged from the J4 test cell was monitored to estimate the average rate of ground-water withdrawal at the J4 test cell. Ground- water levels were monitored continuously at 14 wells for 12 months. Water-quality samples were collected from 26 of the new wells, 9 existing wells, and the ground-water discharge from the J4 test cell. All samples were analyzed for common inorganic ions, trace metals, and volatile organic compounds.

  16. Bridging the scales in a eulerian air quality model to assess the impact of megacity pollution export at the regional level

    NASA Astrophysics Data System (ADS)

    Siour, Guillaume; Colette, Augustin; Bessagnet, Bertrand; Coll, Isabelle; Meleux, Frederik; Menut, Laurent

    2010-05-01

    Investigations of the impact of megacities on the atmospheric environment benefit from a multiscale approach, because megacities provide a large part of the total anthropogenic emissions of trace species that have an impact on air quality at all scales. At the local scale, the accumulation of these primary compounds is responsible for severe respiratory problems and for the alteration of buildings. At the regional scale, they lead to the formation of secondary compounds such as ozone or organic particulate matter witch - in addition to their adverse effects of health - have an impact on the climate equilibrium. Bridging the local and regional scales in a dynamic fashion would thus improve the characterisation of local pollution export from megacities and their regional impact. One of the main objectives of the CityZen project is to assess the interactions between spatial scales. This paper contributes to this activity with a focus on local to regional exchanges. The spatial interactions are often represented through off-line coupling of Chemistry Transport Models (CTM). The interactions from the global to the regional scale are well represented by state-of-the-art nested models. However the off-line coupling from the local to the regional and continental scales introduces a bias in the representation of local plumes on the chemistry of the larger scale. Such phenomena can be captured by means of two way nesting in a coupled model or data assimilation. But these approaches remain relatively costly. We present here the development and the results of an alternative multiscale approach making use of a horizontal stretched grid in the Eulerian CTM CHIMERE. This method consists in the introduction of local zooms over megacities in a continental chemistry-transport simulation within a single grid with variable resolution. It allows bridging online the spatial scales from the city (~1km resolution) to the continental area (~50km resolution). The CHIMERE grid being regular

  17. Evaluating ammonia (NH3) predictions in the NOAA National Air Quality Forecast Capability (NAQFC) using in situ aircraft, ground-level, and satellite measurements from the DISCOVER-AQ Colorado campaign

    NASA Astrophysics Data System (ADS)

    Battye, William H.; Bray, Casey D.; Aneja, Viney P.; Tong, Daniel; Lee, Pius; Tang, Youhua

    2016-09-01

    The U.S. National Oceanic and Atmospheric Administration (NOAA) is responsible for forecasting elevated levels of air pollution within the National Air Quality Forecast Capability (NAQFC). The current research uses measurements gathered in the DISCOVER-AQ Colorado field campaign and the concurrent Front Range Air Pollution and Photochemistry Experiment (FRAPPE) to test performance of the NAQFC CMAQ modeling framework for predicting NH3. The DISCOVER-AQ and FRAPPE field campaigns were carried out in July and August 2014 in Northeast Colorado. Model predictions are compared with measurements of NH3 gas concentrations and the NH4+ component of fine particulate matter concentrations measured directly by the aircraft in flight. We also compare CMAQ predictions with NH3 measurements from ground-based monitors within the DISCOVER-AQ Colorado geographic domain, and from the Tropospheric Emission Spectrometer (TES) on the Aura satellite. In situ aircraft measurements carried out in July and August of 2014 suggest that the NAQFC CMAQ model underestimated the NH3 concentration in Northeastern Colorado by a factor of ∼2.7 (NMB = -63%). Ground-level monitors also produced a similar result. Average satellite-retrieved NH3 levels also exceeded model predictions by a factor of 1.5-4.2 (NMB = -33 to -76%). The underestimation of NH3 was not accompanied by an underestimation of particulate NH4+, which is further controlled by factors including acid availability, removal rate, and gas-particle partition. The average measured concentration of NH4+ was close to the average predication (NMB = +18%). Seasonal patterns measured at an AMoN site in the region suggest that the underestimation of NH3 is not due to the seasonal allocation of emissions, but to the overall annual emissions estimate. The underestimation of NH3 varied across the study domain, with the largest differences occurring in a region of intensive agriculture near Greeley, Colorado, and in the vicinity of Denver. The

  18. Air Toxics in New England | US EPA

    EPA Pesticide Factsheets

    2017-04-10

    Find general information about air toxics, what EPA is doing to reduce ambient air toxics levels, information on the reductions we have seen to date from large New England manufacturing companies, as well as links to other related websites.

  19. Establishment of trigger levels to steer the follow-up of radiation effects in patients undergoing fluoroscopically-guided interventional procedures in Belgium.

    PubMed

    Struelens, L; Bacher, K; Bosmans, H; Bleeser, F; Hoornaert, M T; Malchair, F; Balter, S

    2014-12-01

    The accumulated dose to the skin of the patient during fluoroscopically-guided procedures can exceed the thresholds for tissue reactions. In practice, interventionalists have no direct information about the local procedure-related skin doses in their patient, causing suboptimal or delayed treatment. In current study, the accumulated Kerma-Area-Product (KAP) values were registered, as well as the reference air kerma (Ka,r) values, if available, for almost 200 cases undergoing seven different procedures. A sheet filled with 50 thermoluminescent dosemeters was wrapped around each patient to measure the peak skin dose. In a significant part of the Transjugular Intrahepatic Portosystemic Shunt (TIPSS) procedures, chemo-embolizations of the liver and cerebral embolizations, the threshold values for deterministic skin damage (2 Gy) were attained. Trigger values in terms of KAP, corresponding to a peak skin dose of 2 Gy, were determined. In general, our results comply reasonably well with the values proposed in the NCRP 168 report, with a KAP value of 425 Gy cm² and a Ka,r value of 3 Gy, corresponding to a peak skin dose of 3 Gy. Only for the TIPSS procedure a considerably lower value of 2 Gy was obtained at the published Ka,r and for the RF ablations we obtained a considerably lower value of 250 Gy cm² in terms of KAP.

  20. Air Apparent.

    ERIC Educational Resources Information Center

    Harbster, David A.

    1988-01-01

    Explains the principle upon which a barometer operates. Describes how to construct two barometric devices for use in the classroom that show air's changing pressure. Cites some conditions for predicting weather. (RT)

  1. Air Abrasion

    MedlinePlus

    ... information you need from the Academy of General Dentistry Sunday, April 9, 2017 About | Contact InfoBites Quick ... general dentist, who has been trained in restorative dentistry techniques, will perform any procedures that use air- ...

  2. Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO2) in a medium size city in Northern Spain.

    PubMed

    Parra, M A; Elustondo, D; Bermejo, R; Santamaría, J M

    2009-01-15

    Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO2) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO2 samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO(2) were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 microg m(-3) respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO2 occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO2 exceeded the European limits at some of the monitored points.

  3. 2016 Targeted Air Shed Grant Program - Closed Announcement FY 2016

    EPA Pesticide Factsheets

    Targeted Air Shed Grant Program proposal for FY 2016. The overall goal of the program is to reduce air pollution in the Nation’s areas with the highest levels of ozone and PM2.5 ambient air concentrations.

  4. AIR POLLUTION AND HUMMINGBIRDS

    EPA Science Inventory

    A multidisciplinary team of EPA-RTP ORD pulmonary toxicologists, engineers, ecologists, and statisticians have designed a study of how ground-level ozone and other air pollutants may influence feeding activity of the ruby-throated hummingbird (Archilochus colubris). Be...

  5. Breathing Easy over Air Quality.

    ERIC Educational Resources Information Center

    Greim, Clifton; Turner, William

    1991-01-01

    School systems should test the air in every school building for the presence and level of contaminants such as radon and asbestos and whether the ventilation system is circulating the proper amount of air. Periodic maintenance is required for all mechanical systems. (MLF)

  6. Air/fuel ratio controller

    SciTech Connect

    Schechter, M.M.; Simko, A.O.

    1980-12-23

    An internal combustion engine has a fuel injection pump and an air/fuel ratio controller. The controller has a lever that is connected to the pump lever. An aneroid moves the controller lever as a function of changes in intake manifold vacuum to maintain a constant air/fuel ratio to the mixture charge. A fuel enrichment linkage is provided that modifies the movement of the fuel flow control lever by the aneroid in response to changes in manifold gas temperature levels and exhaust gas recirculation to maintain the constant air/fuel ratio. A manual override is provided to obtain a richer air/fuel ratio for maximum acceleration.

  7. Environmental control: operating room air quality.

    PubMed

    Bartley, J M

    1993-01-01

    1. OR staff members should familiarize themselves with basic air handling system terminology to better manage their own environment (eg, HVAC, air changes, air balancing, HEPA filtration). A working relationship with building engineers is an important skill for the OR nurse. 2. Knowledge of the standards on which air quality in the OR is based should assist in the process of planning for improved design--as well as in monitoring existing air quality. 3. Current standards balance energy savings with air changes and high levels of filtration to achieve optimum outcomes. Recommendations from design and engineering authorities (even for implant surgery) are based on average air changes and HEPA filtration, not laminar air flow. 4. The daily, operational role of the OR staff in maintaining high air quality includes managing traffic, using low-lint barrier materials, monitoring air quality indicators, and investigating unusual variances with the engineering staff for appropriate follow-up (eg, filter changes).

  8. Hazardous Air Pollutants

    MedlinePlus

    ... Air Toxics Website Rules and Implementation Related Information Air Quality Data and Tools Clean Air Act Criteria Air ... Resources Visibility and Haze Voluntary Programs for Improving Air Quality Contact Us to ask a question, provide feedback, ...

  9. Space Derived Air Monitor

    NASA Technical Reports Server (NTRS)

    1983-01-01

    COPAMS, Commonwealth of Pennsylvania Air Monitoring System, derives from technology involved in building unmanned spacecraft. The Nimbus spacecraft carried experimental sensors to measure temperature, pressure, ozone, and water vapor, and instruments for studying solar radiation and telemetry. The process which relayed these findings to Earth formed the basis for COPAMS. The COPAMS system consists of data acquisition units which measure and record pollution level, and sense wind speed and direction, etc. The findings are relayed to a central station where the information is computerized. The system is automatic and supplemented by PAQSS, PA Air Quality Surveillance System.

  10. Air surveillance

    SciTech Connect

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  11. Air Cleaning Technologies

    PubMed Central

    2005-01-01

    evaluated an in-room air cleaner with combined UVGI lights and HEPA filtration under 2 conditions: UVGI lights on and UVGI lights off. Experiments were performed using different ventilation rates and using an aerosolized pathogen comprised of Mycobaterium parafortuitum, a surrogate for the bacterium that causes tuberculosis. Effectiveness was measured as equivalent air changes per hour (eACH). This single study formed the body of evidence for our systematic review research question. Experimental Results The eACH rate for the HEPA-UVGI in-room air cleaner was statistically significantly greater when the UV lights were on compared with when the UV lights were off. (P < .05). However, subsequent experiments could not attribute this to the UVGI. Consequently, the results are inconclusive and an estimate of effect (benefit) is uncertain. The study was reviewed by a scientific expert and rated moderate for quality. Further analysis determined that there was some uncertainty in the directness of the outcome measure (eACH); thus, the GRADE level for the quality of the evidence was low indicating that an estimate of effect is very uncertain. There is uncertainty in the benefits of using in-room air cleaners with combined UVGI lights and HEPA filtration over systems that use HEPA filtration alone. However, there are no known risks to using systems with combined UVGI and HEPA technology compared with those with HEPA alone. There is an increase in the burden of cost including capital costs (cost of the device), operating costs (electricity usage), and maintenance costs (cleaning and replacement of UVGI lights) to using an in-room air cleaner with combined UVGI and HEPA technology compared with those with HEPA alone. Given the uncertainty of the estimate of benefits, an in-room air cleaner with HEPA technology only may be an equally reasonable alternative to using one with combined UVGI and HEPA technology Conclusions In-room air cleaners may be used to protect health care staff from

  12. Air Sparging Design Paradigm

    DTIC Science & Technology

    2002-08-12

    that the air distribution in the aquifer is non-uniform about the air injection, exhibiting tendencies to flow along the axis defined by MP6 , MP12...MW2 MW9 MW7 MW1 MW3 MP9, N9 MP11, N11 MP5, N5 MP7, N7 MP12, N12 MP6 , N6 MP3, N3MP1, N1 - Multi-level sampler and neutron access tube - Air...MP9 and MP12. This hypothesis is supported by the high saturations at MP3, MP6 , MP9 and MP12 in the upper part of the aquifer (3 to 4 m BGS) and low

  13. /Air Atmospheres

    NASA Astrophysics Data System (ADS)

    Emami, Samar; Sohn, Hong Yong; Kim, Hang Goo

    2014-08-01

    Molten magnesium oxidizes rapidly when exposed to air causing melt loss and handling difficulties. The use of certain additive gases such as SF6, SO2, and CO2 to form a protective MgO layer over a magnesium melt has been proposed. The oxidation behavior of molten magnesium in air containing various concentrations of SF6 was investigated. Measurements of the kinetics of the oxide layer growth at various SF6 concentrations in air and temperatures were made. Experiments were performed using a thermogravimetric analysis unit in the temperature range of 943 K to 1043 K (670 °C to 770 °C). Results showed that a thin, coherent, and protective MgF2 layer was formed under SF6/Air mixtures, with a thickness ranging from 300 nm to 3 μm depending on SF6 concentration, temperature, and exposure time. Rate parameters were calculated and a model for the process was developed. The morphology and composition of the surface films were studied using scanning electron microscope and energy-dispersive spectroscope.

  14. Air Pollution.

    ERIC Educational Resources Information Center

    Scorer, Richard S.

    The purpose of this book is to describe the basic mechanisms whereby pollution is transported and diffused in the atmosphere. It is designed to give practitioners an understanding of basic mechanics and physics so they may have a correct basis on which to formulate their decisions related to practical air pollution control problems. Since many…

  15. Skin dosimetry of patients during interventional cardiology procedures in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Sukupova, Lucie; Novak, Leos

    2008-01-01

    The aim of the study is to determine distribution of air kerma-area product, fluoro time and number of frames values for the two most frequent procedures in the interventional cardiology, to reconstruct skin dose distributions for some patients undergoing coronarography and percutaneous transluminal coronary angioplasty procedures. Patient dose data were obtained from X-ray unit dose monitoring software report from one hospital and the reconstructions were performed in MATLAB. Dependence of maximum skin dose on air kerma-area product, fluoro time and number of frames was determined to assess trigger levels of these quantities, which can indicate possible exceeding of the 2 Gy skin dose threshold.

  16. The Crisis in Air Pollution Manpower Development

    ERIC Educational Resources Information Center

    Moeller, Dade W.

    1974-01-01

    Three studies conducted by the National Air Pollution Manpower Development Advisory Committee concluded there is a crisis in air pollution manpower development within the United States today. The studies investigated the existing federal manpower program, air pollution educational requirements and the quality of graduate level university programs.…

  17. CRITICAL HEALTH ISSUES OF CRITERIA AIR POLLUTANTS

    EPA Science Inventory

    This chapter summarizes the key health information on ubiquitous outdoor air pollutants that can cause adverse health effects at current or historical ambient levels in the United States. Of the thousands of air pollutants, very few meet this definition. The Clean Air Act (CA...