Science.gov

Sample records for source emission rate

  1. Comparison of CALPUFF and ISCST3 models for predicting downwind odor and source emission rates

    NASA Astrophysics Data System (ADS)

    Wang, Lingjuan; Parker, David B.; Parnell, Calvin B.; Lacey, Ronald E.; Shaw, Bryan W.

    CALPUFF model and ISCST3 Gaussian dispersion models were evaluated for predicting downwind odor concentrations and back-calculating area source odor emission rates. The comparison between the predicted and field-sampled downwind concentrations indicates that the CALPUFF model could fairly well predict average downwind odor concentrations. However, ISCST3 tended to under predict downwind odor concentrations as compared to the measured concentrations. Both the CALPUFF and ISCST3 models failed to predict peak odor concentrations using the constant average emission rate. Odor emission rates obtained by back-calculating fluxes using CALPUFF and ISC models with the same field measurements of downwind odor concentrations are significantly different. It indicates that back-calculated emission rates are model specific. The modeled emission rates tended to be higher than flux chamber source sampling results. The flux chamber protocol may under-estimate odor emission rates.

  2. Odor emission rate estimation of indoor industrial sources using a modified inverse modeling method.

    PubMed

    Li, Xiang; Wang, Tingting; Sattayatewa, Chakkrid; Venkatesan, Dhesikan; Noll, Kenneth E; Pagilla, Krishna R; Moschandreas, Demetrios J

    2011-08-01

    Odor emission rates are commonly measured in the laboratory or occasionally estimated with inverse modeling techniques. A modified inverse modeling approach is used to estimate source emission rates inside of a postdigestion centrifuge building of a water reclamation plant. Conventionally, inverse modeling methods divide an indoor environment in zones on the basis of structural design and estimate source emission rates using models that assume homogeneous distribution of agent concentrations within a zone and experimentally determined link functions to simulate airflows among zones. The modified approach segregates zones as a function of agent distribution rather than building design and identifies near and far fields. Near-field agent concentrations do not satisfy the assumption of homogeneous odor concentrations; far-field concentrations satisfy this assumption and are the only ones used to estimate emission rates. The predictive ability of the modified inverse modeling approach was validated with measured emission rate values; the difference between corresponding estimated and measured odor emission rates is not statistically significant. Similarly, the difference between measured and estimated hydrogen sulfide emission rates is also not statistically significant. The modified inverse modeling approach is easy to perform because it uses odor and odorant field measurements instead of complex chamber emission rate measurements.

  3. Size-Resolved Source Emission Rates of Indoor Ultrafine Particles Considering Coagulation.

    PubMed

    Rim, Donghyun; Choi, Jung-Il; Wallace, Lance A

    2016-09-20

    Indoor ultrafine particles (UFP, <100 nm) released from combustion and consumer products lead to elevated human exposure to UFP. UFP emitted from the sources undergo aerosol transformation processes such as coagulation and deposition. The coagulation effect can be significant during the source emission due to high concentration and high mobility of nanosize particles. However, few studies have estimated size-resolved UFP source emission strengths while considering coagulation in their theoretical and experimental research work. The primary objective of this study is to characterize UFP source strength by considering coagulation in addition to other indoor processes (i.e., deposition and ventilation) in a realistic setting. A secondary objective is to test a hypothesis that size-resolved UFP source emission rates are unimodal and log-normally distributed for three common indoor UFP sources: an electric stove, a natural gas burner, and a paraffin wax candle. Experimental investigations were performed in a full-scale test building. Size- and time-resolved concentrations of UFP ranging from 2 to 100 nm were monitored using a scanning mobility particle sizer (SMPS). Based on the temporal evolution of the particle size distribution during the source emission period, the size-dependent source emission rate was determined using a material-balance modeling approach. The results indicate that, for a given UFP source, the source strength varies with particle size and source type. The analytical model assuming a log-normally distributed source emission rate could predict the temporal evolution of the particle size distribution with reasonable accuracy for the gas stove and the candle. Including the effect of coagulation was found to increase the estimates of source strengths by up to a factor of 8. This result implies that previous studies on indoor UFP source strengths considering only deposition and ventilation might have largely underestimated the true values of UFP source

  4. Inference of emission rates from multiple sources using Bayesian probability theory.

    PubMed

    Yee, Eugene; Flesch, Thomas K

    2010-03-01

    The determination of atmospheric emission rates from multiple sources using inversion (regularized least-squares or best-fit technique) is known to be very susceptible to measurement and model errors in the problem, rendering the solution unusable. In this paper, a new perspective is offered for this problem: namely, it is argued that the problem should be addressed as one of inference rather than inversion. Towards this objective, Bayesian probability theory is used to estimate the emission rates from multiple sources. The posterior probability distribution for the emission rates is derived, accounting fully for the measurement errors in the concentration data and the model errors in the dispersion model used to interpret the data. The Bayesian inferential methodology for emission rate recovery is validated against real dispersion data, obtained from a field experiment involving various source-sensor geometries (scenarios) consisting of four synthetic area sources and eight concentration sensors. The recovery of discrete emission rates from three different scenarios obtained using Bayesian inference and singular value decomposition inversion are compared and contrasted.

  5. Air pollutant emission rates for sources at the Deaf Smith County repository site

    SciTech Connect

    Not Available

    1985-11-01

    This document summarizes the air-quality source terms used for the Deaf Smith County, Texas environmental assessment report and explains their derivation. The engineering data supporting these source terms appear as appendixes to this report and include summary equipment lists for the repository and detailed equipment lists for the exploratory shaft. Although substantial work has been performed in establishing the current repository design, a greater effort will be required for the final design. Consequently, the repository emission rates presented here should be considered as preliminary estimates. Another set of air pollution emission rates will be calculated after design data are more firmly established. 18 refs., 15 tabs.

  6. Odor Sampling: Techniques and Strategies for the Estimation of Odor Emission Rates from Different Source Types

    PubMed Central

    Capelli, Laura; Sironi, Selena; Rosso, Renato Del

    2013-01-01

    Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. The most important information about an emission source for odor impact assessment is the so-called Odor Emission Rate (OER), which represents the quantity of odor emitted per unit of time, and is expressed in odor units per second (ou·s−1). This paper reviews the different odor sampling strategies adopted depending on source type. The review includes an overview of odor sampling regulations and a detailed discussion of the equipment to be used as well as the mathematical considerations to be applied to obtain the OER in relation to the sampled source typology. PMID:23322098

  7. GAS-PHASE MASS TRANSFER MODEL FOR PREDICTING VOLATILE ORGANIC COMPOUND (VOC) EMISSION RATES FROM INDOOR POLLUTANT SOURCES

    EPA Science Inventory

    Analysis of the impact of sources on indoor pollutant concentrations and occupant exposure to indoor pollutants requires knowledge of the emission rates from the sources. Emission rates are often determined by chamber testing and the data from the chamber test are fitted to an em...

  8. Observed Barium Emission Rates

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  9. Optimizing the Point-Source Emission Rates and Geometries of Pheromone Mating Disruption Mega-Dispensers.

    PubMed

    Baker, T C; Myrick, A J; Park, K C

    2016-09-01

    High-emission-rate "mega-dispensers" have come into increasing use for sex pheromone mating disruption of moth pests over the past two decades. These commercially available dispensers successfully suppress mating and reduce crop damage when they are deployed at very low to moderate densities, ranging from 1 to 5/ha to 100-1000/ha, depending on the dispenser types and their corresponding pheromone emission rates. Whereas traditionally the emission rates for successful commercial mating disruption formulations have been measured in terms of amounts (usually milligram) emitted by the disruptant application per acre or hectare per day, we suggest that emission rates should be measured on a per-dispenser per-minute basis. In addition we suggest, because of our knowledge concerning upwind flight of male moths being dependent on contact with pheromone plume strands, that more attention needs to be paid to optimizing the flux within plume strands that shear off of any mating disruption dispenser's surface. By measuring the emission rates on a per-minute basis and measuring the plume strand concentrations emanating from the dispensers, it may help improve the ability of the dispensers to initiate upwind flight from males and initiate their habituation to the pheromone farther downwind than can otherwise be achieved. In addition, by optimizing plume strand flux by paying attention to the geometries and compactness of mating disruption mega-dispensers may help reduce the cost of mega-dispenser disruption formulations by improving their behavioral efficacy while maintaining field longevity and using lower loading rates per dispenser.

  10. Estimation of point source fugitive emission rates from a single sensor time series: a conditionally-sampled Gaussian plume reconstruction

    EPA Science Inventory

    This paper presents a technique for determining the trace gas emission rate from a point source. The technique was tested using data from controlled methane release experiments and from measurement downwind of a natural gas production facility in Wyoming. Concentration measuremen...

  11. Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a SingleDownwind High-Frequency Gas Sensor

    EPA Science Inventory

    Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a Single Downwind High-Frequency Gas Sensor With the tremendous advances in onshore oil and gas exploration and production (E&P) capability comes the realization that new tools are needed to support env...

  12. Measurement of the emission rate of an aerosol source--comparison of aerosol and gas transport coefficients.

    PubMed

    Bémer, D; Callé, S; Godinot, S; Régnier, R; Dessagne, J M

    2000-12-01

    A measuring method of the emission rate of an atmospheric pollutant source, based on the use of a tracer gas (helium) and developed in the case of a gaseous source, was tested for an aerosol source. The influence of both particle sedimentation and wall depositions was studied. The transport coefficients of the tracer gas and of alumina particles of various particle sizes (MMAD from 8 to 36 microns) were measured on a vertical axis close to the source, in a 71 m3 room swept by a piston flow. The measurements clearly demonstrated the predominant influence of sedimentation in the case of particles with aerodynamic diameters greater than 10 microns. Particle wall deposition was determined by measuring the gas and particle concentration decay in the ventilated room. To do this, a new tracing method using a fluorescent aerosol was developed. The measured aerosol deposition rates are much higher than those calculated from the formula of Corner for a cubical volume. Aerosol sedimentation and wall deposition are two phenomena limiting the use of a tracer gas to measure the aerosol emission rate. The chemical substances and materials used in work premises are likely to be released into the atmosphere and lead to the formation of pollutants. These emissions stem from either physical or chemical processes (evaporation of a solvent) or from mechanical processes (dispersion of oil droplets at the source of mists).

  13. Analysis of available ambient and stationary source HAP sampling results to verify emission rate estimates for sources in Ambos Nogales

    SciTech Connect

    Powers, B.; Fernandez, C.; Oliver, B.; Dickson, R.

    1996-12-31

    The Arizona Department of Environmental Quality (ADEQ) is funding a project to develop comprehensive hazardous air pollutant (HAP) emissions inventories for the cross-border communities of Nogales, Arizona and Nogales, Sonora, Mexico. Ambient VOC and PAH data were collected in downtown Nogales, Sonora in July 1994 by the ADEQ. This paper addresses the analysis of the ambient HAP data performed by the project team. The ambient HAP data evaluation will serve as a cross-check of the accuracy of the RAP emission estimates developed for each source type included in the HAP emissions inventory. The data show that benzene, toluene, xylene, ethylbenzene (BTXE) and aldehydes are the dominant volatile organic compound (VOC) HAPs in the ambient air. The quantity of BTXE in the ambient air, and ratio of these compounds to each other, implies that mobile sources are the principal source of BTXE in Nogales, Sonora. Significant levels of olefinic VOCs were also detected. Ambient test data also indicate ethane, propane, butane, pentane are the predominant VOC species in the ambient air. Liquified petroleum gas (LPG) cylinders are the probable source of these VOCs. Almost all residential and commercial cooking performed in Nogales, Sonora is done from LPG cylinders containing a mixture of propane (primarily) and butane. These cylinders are ubiquitous, and many are equipped with potentially leaky valves. VOC and VOC HAP test protocols are currently being developed by the Mexican National Institute of Ecology for these cylinders and associated cooking ranges. Periodic open burning of municipal solid waste (MSW) is performed at a site located on the border in Nogales, Sonora. Ambient VOC HAP data collected in July 1994 during both MSW burning periods and {open_quotes}no burn{close_quotes} periods is being evaluated to determine if the contribution of open burning to the ambient HAP burden can be estimated for both particulate and VOC HAPs from the ambient data. 7 refs.

  14. The content of 250Cf and 248Cm in 252Cf neutron sources and the effect on the neutron emission rate.

    PubMed

    Roberts, N J; Jones, L N

    2007-01-01

    One of the most common radionuclide neutron sources used for the calibration of detectors is (252)Cf. However, these sources also contain (250)Cf, which is present in the material from which the sources are made, and (248)Cm, which is formed as the daughter of (252)Cf via alpha-decay. Both decay by spontaneous fission with longer half-lives than (252)Cf. Consequently, as the source becomes older, the emission rate does not follow the decay curve of (252)Cf. Fits have been made to emission rate measurements of (252)Cf sources at NPL spanning over 30 y to deduce their (250)Cf and (248)Cm content. The emission rate of a source can be significantly underestimated if the presence of (250)Cf and (248)Cm is not taken into account, and this has been investigated for a typical (252)Cf source. The importance of this problem to other calibration laboratories and users of (252)Cf sources is emphasised.

  15. Field emission electron source

    DOEpatents

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  16. Global Scale Attribution of Anthropogenic and Natural Dust Sources and their Emission Rates Based on MODIS Deep Blue Aerosol Products

    NASA Technical Reports Server (NTRS)

    Ginoux, Paul; Prospero, Joseph M.; Gill, Thomas E.; Hsu, N. Christina; Zhao, Ming

    2012-01-01

    Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Here we present a global-scale high-resolution (0.1 deg) mapping of sources based on Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue estimates of dust optical depth in conjunction with other data sets including land use. We ascribe dust sources to natural and anthropogenic (primarily agricultural) origins, calculate their respective contributions to emissions, and extensively compare these products against literature. Natural dust sources globally account for 75% of emissions; anthropogenic sources account for 25%. North Africa accounts for 55% of global dust emissions with only 8% being anthropogenic, mostly from the Sahel. Elsewhere, anthropogenic dust emissions can be much higher (75% in Australia). Hydrologic dust sources (e.g., ephemeral water bodies) account for 31% worldwide; 15% of them are natural while 85% are anthropogenic. Globally, 20% of emissions are from vegetated surfaces, primarily desert shrublands and agricultural lands. Since anthropogenic dust sources are associated with land use and ephemeral water bodies, both in turn linked to the hydrological cycle, their emissions are affected by climate variability. Such changes in dust emissions can impact climate, air quality, and human health. Improved dust emission estimates will require a better mapping of threshold wind velocities, vegetation dynamics, and surface conditions (soil moisture and land use) especially in the sensitive regions identified here, as well as improved ability to address small-scale convective processes producing dust via cold pool (haboob) events frequent in monsoon regimes.

  17. Exploiting dual otoacoustic emission sources

    NASA Astrophysics Data System (ADS)

    Abdala, Carolina; Kalluri, Radha

    2015-12-01

    Two distinct processes generate otoacoustic emissions (OAEs). Reflection-source emissions, here recorded as stimulus frequency OAEs, are optimally informative at low sound levels and are more sensitive to slight hearing loss; they have been linked to cochlear amplifier gain and tuning. Distortion-source emissions are strongest at moderate-high sound levels and persist despite mild hearing loss; they likely originate in the nonlinear process of hair cell transduction. In this preliminary study, we exploit the unique features of each by generating a combined reflection-distortion OAE profile in normal hearing and hearing-impaired ears. Distortion-product (DP) and stimulus-frequency (SF) OAEs were recorded over a broad range of stimulus levels and frequencies. Individual I/O and transfer functions were generated for both emission types in each ear, and OAE peak strength, compression threshold, and rate of compression were calculated. These combined SFOAE and DPOAE features in normal and hearing-impaired ears may provide a potentially informative and novel index of hearing loss. This is an initial step toward utilizing OAE source in characterizing cochlear function and dysfunction.

  18. Minimization of nitrous oxide emission from CASS process treating low carbon source domestic wastewater: Effect of feeding strategy and aeration rate.

    PubMed

    Liang, Weihao; Yu, Chao; Ren, Hongqiang; Geng, Jinju; Ding, Lili; Xu, Ke

    2015-12-01

    Nitrous oxide (N2O) emission during wastewater treatment can be mitigated by improving operational conditions, e.g., organic carbon supply and dissolved oxygen. To evaluate the control parameters for N2O emission in the low carbon source domestic wastewater treatment process, N2O emissions from Cyclic Activated Sludge System (CASS) under different feeding strategies and aeration rates were investigated. Results showed that continuous feeding enhanced nitrogen removal and reduced N2O emission compared to batch feeding, while a higher aeration rate led to less N2O emission. N2O was mainly produced during non-aeration phases in batch feeding CASS and the amount of N2O generated from denitrification decreased under continuous feeding, indicating that carbon source in the continuous influent relieved the electron competition between denitrification reductases during non-aeration phase. Moreover, taxonomic analysis based on high-throughput 16S rRNA gene sequencing revealed higher abundance of denitrifying bacteria, especially N2O-reducing bacteria in continuous feeding CASS.

  19. VOCs emission rate estimate for complicated industrial area source using an inverse-dispersion calculation method: A case study on a petroleum refinery in Northern China.

    PubMed

    Wei, Wei; Lv, Zhaofeng; Yang, Gan; Cheng, Shuiyuan; Li, Yue; Wang, Litao

    2016-11-01

    This study aimed to apply an inverse-dispersion calculation method (IDM) to estimate the emission rate of volatile organic compounds (VOCs) for the complicated industrial area sources, through a case study on a petroleum refinery in Northern China. The IDM was composed of on-site monitoring of ambient VOCs concentrations and meteorological parameters around the source, calculation of the relationship coefficient γ between the source's emission rate and the ambient VOCs concentration by the ISC3 model, and estimation of the actual VOCs emission rate from the source. Targeting the studied refinery, 10 tests and 8 tests were respectively conducted in March and in June of 2014. The monitoring showed large differences in VOCs concentrations between background and downwind receptors, reaching 59.7 ppbv in March and 248.6 ppbv in June, on average. The VOCs increases at receptors mainly consisted of ethane (3.1%-22.6%), propane (3.8%-11.3%), isobutane (8.5%-10.2%), n-butane (9.9%-13.2%), isopentane (6.1%-12.9%), n-pentane (5.1%-9.7%), propylene (6.1-11.1%) and 1-butylene (1.6%-5.4%). The chemical composition of the VOCs increases in this field monitoring was similar to that of VOCs emissions from China's refineries reported, which revealed that the ambient VOCs increases were predominantly contributed by this refinery. So, we used the ISC3 model to create the relationship coefficient γ for each receptor of each test. In result, the monthly VOCs emissions from this refinery were calculated to be 183.5 ± 89.0 ton in March and 538.3 ± 281.0 ton in June. The estimate in June was greatly higher than in March, chiefly because the higher environmental temperature in summer produced more VOCs emissions from evaporation and fugitive process of the refinery. Finally, the VOCs emission factors (g VOCs/kg crude oil refined) of 0.73 ± 0.34 (in March) and 2.15 ± 1.12 (in June) were deduced for this refinery, being in the same order with previous direct

  20. Measuring the emission rate of an aerosol source placed in a ventilated room using a tracer gas: influence of particle wall deposition.

    PubMed

    Bémer, D; Lecler, M T; Régnier, R; Hecht, G; Gerber, J M

    2002-04-01

    A method to measure the emission rate of an airborne pollutant source using a tracer gas was tested in the case of an aerosol source. The influence of particle deposition on the walls of a test room of 72 m3 was studied. The deposition rate of an aerosol of MgCl2 was determined by means of two methods: one based on measuring the aerosol concentration decay inside the ventilated room, the other based on calculation of the material mass balance. The concentration decay was monitored by optical counting and the aerosol mass concentration determined by means of sampling on a filter and analysis of the mass deposited by atomic absorption spectrometry. Four series of measurements were carried out. The curve giving the deposition rate according to the particle aerodynamic diameter (d(ae)) was established and shows deposition rates higher than those predicted using the model of Corner. The decay method gives the best results. The study carried out has shown that the phenomenon of deposition has little effect on the measurement of the aerosol source emission rate using a tracer gas for particles of aerodynamic diameter < 5 microm (underestimation < 25%). For particles of a greater diameter, wall deposition is an extremely limiting factor for the method, the influence of which can, however, be limited by using a test booth of small volume and keeping the sampling duration as short as possible.

  1. Long term observations of halogenated greenhouse gases in a European continental background station for assessing atmospheric trends, annual growth rates and emission sources

    NASA Astrophysics Data System (ADS)

    Maione, M.; Arduini, J.; Uguccioni, F.; Giostra, U.; Furlani, F.; Belfiore, L.; Cava, D.

    2009-04-01

    Climate altering halocarbons are continuously monitored at the atmospheric research station "O. Vittori" located on the top of Monte Cimone, Northern Apennines, Italy ( 2165 m asl), in the frame of the SOGE (System for Observation of halogenated Greenhouse gases in Europe) network, an integrated system based on a combination of observations and models aimed at assessing atmospheric trends, annual growth rates and at estimating European halocarbon emissions. The use of such a top-down approach is useful to ascertain compliance to International Protocols regulating production/emission of halogenated greenhouse gases. Establishing the baseline is essential both for estimating annual growth rates and because back attribution techniques are based on the clear identification of "above the background" data. That is particularly challenging in a Station like Monte Cimone characterised by a complex meteorological and source field. The approach proposed is based on the identification of the lowest concentration values in a given temporal range to which a ∆c representing variation due to instrumental error is added. Trends are evaluated by using a non-linear regression function, able to take into account both annual and seasonal variation. In order to identify source, regions baseline data are subtracted from the full data set and an inversion modelling cascade, which makes use of MM5 model to reproduce meteorological fields and of FLEXPART to simulate tracer dispersion, is used to find the best emissions map that fits the observations.

  2. International key comparison of measurements of neutron source emission rate (1999-2005): CCRI(III)-K9.AmBe

    NASA Astrophysics Data System (ADS)

    Roberts, N. J.; Jones, L. N.; Wang, Z.; Liu, Y.; Wang, Q.; Chen, X.; Luo, H.; Rong, C.; Králik, M.; Park, H.; Choi, K. O.; Pereira, W. W.; da Fonseca, E. S.; Cassette, P.; Dewey, M. S.; Moiseev, N. N.; Kharitonov, I. A.

    2011-01-01

    Section III (neutron measurements) of the Comité Consultatif des Rayonnements Ionisants, CCRI, conducted a key comparison of primary measurements of the neutron emission rate of an 241Am-Be(α,n) radionuclide source. A single 241Am-Be(α,n) source was circulated to all the participants between 1999 and 2005. Eight laboratories participated—the CIAE (China), CMI (Czech Republic), KRISS (Republic of Korea), LNMRI (Brazil), LNE-LNHB (France), NIST (USA), NPL (UK) and the VNIIM (Russian Federation)—with the NPL making their measurements at the start and repeating them near the end of the exercise to verify the stability of the source. Each laboratory reported the emission rate into 4π sr together with a detailed uncertainty budget. All participants used the manganese bath technique, with the VNIIM also making measurements using an associated particle technique. The CMI, KRISS, VNIIM, and later the NPL, also measured the anisotropy of the source although this was not a formal part of the comparison. The first draft report was released in May 2006 and having been discussed and modified by the participants and subsequently reviewed by the CCRI(III), the present paper is now the final report of the comparison. 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 Section III, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  3. MAMAP - a new spectrometer system for column-averaged methane and carbon dioxide observations from aircraft: retrieval algorithm and first inversions for point source emission rates

    NASA Astrophysics Data System (ADS)

    Krings, T.; Gerilowski, K.; Buchwitz, M.; Reuter, M.; Tretner, A.; Erzinger, J.; Heinze, D.; Burrows, J. P.; Bovensmann, H.

    2011-04-01

    MAMAP is an airborne passive remote sensing instrument designed for measuring columns of methane (CH4) and carbon dioxide (CO2). The MAMAP instrument consists of two optical grating spectrometers: One in the short wave infrared band (SWIR) at 1590-1690 nm to measure CO2 and CH4 absorptions and another one in the near infrared (NIR) at 757-768 nm to measure O2 absorptions for reference purposes. MAMAP can be operated in both nadir and zenith geometry during the flight. Mounted on an airplane MAMAP can effectively survey areas on regional to local scales with a ground pixel resolution of about 29 m × 33 m for a typical aircraft altitude of 1250 m and a velocity of 200 km h-1. The retrieval precision of the measured column relative to background is typically ≲ 1% (1σ). MAMAP can be used to close the gap between satellite data exhibiting global coverage but with a rather coarse resolution on the one hand and highly accurate in situ measurements with sparse coverage on the other hand. In July 2007 test flights were performed over two coal-fired powerplants operated by Vattenfall Europe Generation AG: Jänschwalde (27.4 Mt CO2 yr-1) and Schwarze Pumpe (11.9 Mt CO2 yr-1), about 100 km southeast of Berlin, Germany. By using two different inversion approaches, one based on an optimal estimation scheme to fit Gaussian plume models from multiple sources to the data, and another using a simple Gaussian integral method, the emission rates can be determined and compared with emissions as stated by Vattenfall Europe. An extensive error analysis for the retrieval's dry column results (XCO2 and XCH4) and for the two inversion methods has been performed. Both methods - the Gaussian plume model fit and the Gaussian integral method - are capable of delivering reliable estimates for strong point source emission rates, given appropriate flight patterns and detailed knowledge of wind conditions.

  4. Global-scale attribution of anthropogenic and natural dust sources and their emission rates based on MODIS Deep Blue aerosol products

    NASA Astrophysics Data System (ADS)

    Ginoux, Paul; Prospero, Joseph M.; Gill, Thomas E.; Hsu, N. Christina; Zhao, Ming

    2012-09-01

    Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Here we present a global-scale high-resolution (0.1°) mapping of sources based on Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue estimates of dust optical depth in conjunction with other data sets including land use. We ascribe dust sources to natural and anthropogenic (primarily agricultural) origins, calculate their respective contributions to emissions, and extensively compare these products against literature. Natural dust sources globally account for 75% of emissions; anthropogenic sources account for 25%. North Africa accounts for 55% of global dust emissions with only 8% being anthropogenic, mostly from the Sahel. Elsewhere, anthropogenic dust emissions can be much higher (75% in Australia). Hydrologic dust sources (e.g., ephemeral water bodies) account for 31% worldwide; 15% of them are natural while 85% are anthropogenic. Globally, 20% of emissions are from vegetated surfaces, primarily desert shrublands and agricultural lands. Since anthropogenic dust sources are associated with land use and ephemeral water bodies, both in turn linked to the hydrological cycle, their emissions are affected by climate variability. Such changes in dust emissions can impact climate, air quality, and human health. Improved dust emission estimates will require a better mapping of threshold wind velocities, vegetation dynamics, and surface conditions (soil moisture and land use) especially in the sensitive regions identified here, as well as improved ability to address small-scale convective processes producing dust via cold pool (haboob) events frequent in monsoon regimes.

  5. MAMAP - a new spectrometer system for column-averaged methane and carbon dioxide observations from aircraft: retrieval algorithm and first inversions for point source emission rates

    NASA Astrophysics Data System (ADS)

    Krings, T.; Gerilowski, K.; Buchwitz, M.; Reuter, M.; Tretner, A.; Erzinger, J.; Heinze, D.; Pflüger, U.; Burrows, J. P.; Bovensmann, H.

    2011-09-01

    MAMAP is an airborne passive remote sensing instrument designed to measure the dry columns of methane (CH4) and carbon dioxide (CO2). The MAMAP instrument comprises two optical grating spectrometers: the first observing in the short wave infrared band (SWIR) at 1590-1690 nm to measure CO2 and CH4 absorptions, and the second in the near infrared (NIR) at 757-768 nm to measure O2 absorptions for reference/normalisation purposes. MAMAP can be operated in both nadir and zenith geometry during the flight. Mounted on an aeroplane, MAMAP surveys areas on regional to local scales with a ground pixel resolution of approximately 29 m × 33 m for a typical aircraft altitude of 1250 m and a velocity of 200 km h-1. The retrieval precision of the measured column relative to background is typically ≲ 1% (1σ). MAMAP measurements are valuable to close the gap between satellite data, having global coverage but with a rather coarse resolution, on the one hand, and highly accurate in situ measurements with sparse coverage on the other hand. In July 2007, test flights were performed over two coal-fired power plants operated by Vattenfall Europe Generation AG: Jänschwalde (27.4 Mt CO2 yr-1) and Schwarze Pumpe (11.9 Mt CO2 yr-1), about 100 km southeast of Berlin, Germany. By using two different inversion approaches, one based on an optimal estimation scheme to fit Gaussian plume models from multiple sources to the data, and another using a simple Gaussian integral method, the emission rates can be determined and compared with emissions reported by Vattenfall Europe. An extensive error analysis for the retrieval's dry column results (XCO2 and XCH4) and for the two inversion methods has been performed. Both methods - the Gaussian plume model fit and the Gaussian integral method - are capable of deriving estimates for strong point source emission rates that are within ±10% of the reported values, given appropriate flight patterns and detailed knowledge of wind conditions.

  6. Ultrafast spontaneous emission source using plasmonic nanoantennas

    PubMed Central

    Hoang, Thang B.; Akselrod, Gleb M.; Argyropoulos, Christos; Huang, Jiani; Smith, David R.; Mikkelsen, Maiken H.

    2015-01-01

    Typical emitters such as molecules, quantum dots and semiconductor quantum wells have slow spontaneous emission with lifetimes of 1–10 ns, creating a mismatch with high-speed nanoscale optoelectronic devices such as light-emitting diodes, single-photon sources and lasers. Here we experimentally demonstrate an ultrafast (<11 ps) yet efficient source of spontaneous emission, corresponding to an emission rate exceeding 90 GHz, using a hybrid structure of single plasmonic nanopatch antennas coupled to colloidal quantum dots. The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core–shell quantum dots, a stable and technologically relevant emitter. We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ∼50%. The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission. PMID:26212857

  7. Ultrafast spontaneous emission source using plasmonic nanoantennas.

    PubMed

    Hoang, Thang B; Akselrod, Gleb M; Argyropoulos, Christos; Huang, Jiani; Smith, David R; Mikkelsen, Maiken H

    2015-07-27

    Typical emitters such as molecules, quantum dots and semiconductor quantum wells have slow spontaneous emission with lifetimes of 1-10 ns, creating a mismatch with high-speed nanoscale optoelectronic devices such as light-emitting diodes, single-photon sources and lasers. Here we experimentally demonstrate an ultrafast (<11 ps) yet efficient source of spontaneous emission, corresponding to an emission rate exceeding 90 GHz, using a hybrid structure of single plasmonic nanopatch antennas coupled to colloidal quantum dots. The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core-shell quantum dots, a stable and technologically relevant emitter. We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ∼50%. The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission.

  8. Ultrafast spontaneous emission source using plasmonic nanoantennas

    NASA Astrophysics Data System (ADS)

    Hoang, Thang B.; Akselrod, Gleb M.; Argyropoulos, Christos; Huang, Jiani; Smith, David R.; Mikkelsen, Maiken H.

    2015-07-01

    Typical emitters such as molecules, quantum dots and semiconductor quantum wells have slow spontaneous emission with lifetimes of 1-10 ns, creating a mismatch with high-speed nanoscale optoelectronic devices such as light-emitting diodes, single-photon sources and lasers. Here we experimentally demonstrate an ultrafast (<11 ps) yet efficient source of spontaneous emission, corresponding to an emission rate exceeding 90 GHz, using a hybrid structure of single plasmonic nanopatch antennas coupled to colloidal quantum dots. The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core-shell quantum dots, a stable and technologically relevant emitter. We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ~50%. The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission.

  9. Endocrine disrupting chemical emissions from combustion sources: diesel particulate emissions and domestic waste open burn emissions

    NASA Astrophysics Data System (ADS)

    Sidhu, Sukh; Gullett, Brian; Striebich, Richard; Klosterman, Joy; Contreras, Jesse; DeVito, Michael

    Emissions of endocrine disrupting chemicals (EDCs) from combustion sources are poorly characterized due to the large number of compounds present in the emissions, the complexity of the analytical separations required, and the uncertainty regarding identification of chemicals with endocrine effects. In this work, multidimensional gas chromatographic-mass spectrometry (MDGC-MS) was used to characterize emissions from both controlled (diesel engine) and uncontrolled (open burning of domestic waste) combustion sources. The results of this study suggest that, by using MDGC-MS, one can resolve a much greater percentage of the chromatogram and identify about 84% of these resolved compounds. This increase in resolution helped to identify and quantify various classes of polycyclic aromatic hydrocarbons (PAHs) in the combustion emissions that had not been identified previously. Significant emissions (when compared to industrial sources) of known EDCs, dioctyl phthalate (over ˜2,500,000 kg year -1) and bisphenol A (over ˜75,000 kg year -1) were estimated from uncontrolled domestic waste burning. Emissions of several suspected EDCs (oxygenated PAHs) were observed in both diesel soot and the uncontrolled domestic waste burn samples. The emission rates of known and suspected EDCs estimated in this study suggest that combustion emissions need to be characterized for EDCs to further assess its importance as a source of EDC exposure.

  10. Other Production Emissions Sources- September 2012 Workshop

    EPA Pesticide Factsheets

    View a presentation on other production emissions sources, presented at the Stakeholder Workshop on Natural Gas in the Inventory of U.S. Greenhouse Gas (GHG) Emissions and Sinks on Thursday September, 13, 2012.

  11. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    PubMed

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  12. Atmospheric process evaluation of mobile source emissions

    SciTech Connect

    1995-07-01

    During the past two decades there has been a considerable effort in the US to develop and introduce an alternative to the use of gasoline and conventional diesel fuel for transportation. The primary motives for this effort have been twofold: energy security and improvement in air quality, most notably ozone, or smog. The anticipated improvement in air quality is associated with a decrease in the atmospheric reactivity, and sometimes a decrease in the mass emission rate, of the organic gas and NO{sub x} emissions from alternative fuels when compared to conventional transportation fuels. Quantification of these air quality impacts is a prerequisite to decisions on adopting alternative fuels. The purpose of this report is to present a critical review of the procedures and data base used to assess the impact on ambient air quality of mobile source emissions from alternative and conventional transportation fuels and to make recommendations as to how this process can be improved. Alternative transportation fuels are defined as methanol, ethanol, CNG, LPG, and reformulated gasoline. Most of the discussion centers on light-duty AFVs operating on these fuels. Other advanced transportation technologies and fuels such as hydrogen, electric vehicles, and fuel cells, will not be discussed. However, the issues raised herein can also be applied to these technologies and other classes of vehicles, such as heavy-duty diesels (HDDs). An evaluation of the overall impact of AFVs on society requires consideration of a number of complex issues. It involves the development of new vehicle technology associated with engines, fuel systems, and emission control technology; the implementation of the necessary fuel infrastructure; and an appropriate understanding of the economic, health, safety, and environmental impacts associated with the use of these fuels. This report addresses the steps necessary to properly evaluate the impact of AFVs on ozone air quality.

  13. Radiation source with shaped emission

    DOEpatents

    Kubiak, Glenn D.; Sweatt, William C.

    2003-05-13

    Employing a source of radiation, such as an electric discharge source, that is equipped with a capillary region configured into some predetermined shape, such as an arc or slit, can significantly improve the amount of flux delivered to the lithographic wafers while maintaining high efficiency. The source is particularly suited for photolithography systems that employs a ringfield camera. The invention permits the condenser which delivers critical illumination to the reticle to be simplified from five or more reflective elements to a total of three or four reflective elements thereby increasing condenser efficiency. It maximizes the flux delivered and maintains a high coupling efficiency. This architecture couples EUV radiation from the discharge source into a ring field lithography camera.

  14. Jovian S emission: Model of radiation source

    NASA Astrophysics Data System (ADS)

    Ryabov, B. P.

    1994-04-01

    A physical model of the radiation source and an excitation mechanism have been suggested for the S component in Jupiter's sporadic radio emission. The model provides a unique explanation for most of the interrelated phenomena observed, allowing a consistent interpretation of the emission cone structure, behavior of the integrated radio spectrum, occurrence probability of S bursts, location and size of the radiation source, and fine structure of the dynamic spectra. The mechanism responsible for the S bursts is also discussed in connection with the L type emission. Relations are traced between parameters of the radio emission and geometry of the Io flux tube. Fluctuations in the current amplitude through the tube are estimated, along with the refractive index value and mass density of the plasma near the radiation source.

  15. Evaluation of Mobile Source Emissions and Trends

    NASA Astrophysics Data System (ADS)

    Dallmann, Timothy Ryan

    Mobile sources contribute significantly to air pollution problems. Relevant pollutants include numerous gaseous and particle-phase species that can affect human health, ecosystems, and climate. Accurate inventories of emissions from these sources are needed to help understand possible adverse impacts, and to develop effective air quality management strategies. Unfortunately large uncertainties persist in the understanding of mobile source emissions, and how these emissions are changing over time. This dissertation aims to evaluate long-term trends in mobile source emissions in the United States, and to make detailed measurements of emissions from present-day fleets of on-road vehicles operating in California. Long-term trends in mobile source emissions of nitrogen oxides (NO x) and fine particulate matter (PM2.5) in the United States were investigated through development of a fuel-based emission inventory. Annual emissions from on- and off-road gasoline and diesel engines were quantified for the years 1996-2006. Diesel engines were found to be the dominant mobile source of NOx and PM2.5, and on-road diesel vehicles were identified as the single largest anthropogenic source of NOx emissions in the United States as of 2005. The importance of diesel engines as a source of exhaust particulate matter emissions has led to the recent introduction of advanced emission control technologies in the United States, such as diesel particle filters (DPF), which have been required since 2007 for all new on-road heavy-duty (HD) diesel engines. In addition to national requirements for the use of such control devices on new engines, California has mandated accelerated clean-up of statewide emissions from older in-use diesel engines. The plume capture method was further applied to measure emissions from a more diverse population of trucks observed at the Caldecott tunnel in summer 2010. Emissions from hundreds of individual trucks were measured, and emission factor distributions were

  16. Controlling NOx emission from industrial sources

    SciTech Connect

    Srivastava, R.K.; Nueffer, W.; Grano, D.; Khan, S.; Staudt, J.E.; Jozewicz, W.

    2005-07-01

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other bills in the Congress are focusing on additional reductions of NOx. Industrial combustion sources accounted for about 18016 of NOx emissions in the United States in 2000 and constituted the second largest emitting source category within stationary sources, only behind electric utility sources. Based on these data, reduction of NOx emissions from industrial combustion sources is an important consideration in efforts undertaken to address the environmental concerns associated with NOx. This paper discusses primary and secondary NOx control technologies applicable to various major categories of industrial sources. The sources considered in this paper include large boilers, furnaces and fired heaters, combustion turbines, large IC engines, and cement kilns. For each source category considered in this paper, primary NOx controls are discussed first, followed by a discussion of secondary NOx controls.

  17. 40 CFR 74.23 - 1985 Allowable SO2 emissions rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.23 1985 Allowable SO2 emissions rate. (a) Data requirements. (1) The designated representative of the combustion source shall... data: (i) Allowable SO2 emissions rate of the combustion source expressed in lbs/mmBtu as defined...

  18. Polychlorinated Biphenyl Sources, Emissions, and Environmental Levels in school Buildings (PCB Workshop presentation)

    EPA Science Inventory

    Measure PCB emission rates from primary sources in laboratory chambersMeasure transport and sorption by materials and dust in laboratory chambersCharacterize PCBs in school building materialsEstimate PCB emission rates from sources in schoolsExamine congener patterns in sources a...

  19. Calendar Year 2016 Stationary Source Emissions Inventory

    SciTech Connect

    Evelo, Stacie

    2017-01-01

    The City of Albuquerque (COA) Environmental Health Department Air Quality Program has issued stationary source permits and registrations the Department of Energy/Sandia Field Office for operations at the Sandia National Laboratories/New Mexico. This emission inventory report meets the annual reporting compliance requirements for calendar year (CY) 2016 as required by the COA.

  20. Synchro-Compton emission from superluminal sources

    NASA Technical Reports Server (NTRS)

    Marscher, Alan P.

    1987-01-01

    The application of synchro-Compton theory to real compact radio sources, the question of a self-Compton origin of the X-rays in radio-loud quasars and active galactic nuclei, and the phenomenology of superluminal motion are discussed in a review of research concerning synchro-Compton emission from superluminal sources. After examining the basic synchro-Compton theory of ideal sources, applications of the theory to real sources is discussed. It is concluded that the Compton problem and total energy requirements are not substantially mitigated by considering source structures more complicated than the multiple, uniform-component model used by most investigators. Also, alternatives to the standard model of superluminal motion are discussed, focusing on the assumptions usually made when interpreting superluminal sources.

  1. Radio frequency glow discharge source with integrated voltage and current probes used for sputtering rate and emission yield measurements at insulating samples.

    PubMed

    Wilken, L; Hoffmann, V; Wetzig, K

    2005-10-01

    Radio frequency glow discharge optical emission spectroscopy (RF-GD-OES) is routinely used for the chemical analysis of solid samples. Two independent electrical signals from the discharge are required for quantification. When sputtering insulating samples, the voltage over the discharge is not directly measurable. The coupling capacity of the sample is required in order to calculate the discharge voltage. A procedure is outlined where the coupling capacity is determined using an electrical measurement without discharge. The calculated time-dependent discharge voltage and current are evaluated using a plasma equivalent circuit. An insulating sample is sputtered at constant cathode voltage and current. The emission yield for an aluminium line is comparable to that of conducting reference material.

  2. Source emission-pattern polynomial representation

    NASA Astrophysics Data System (ADS)

    Flores-Hernandez, Ricardo; De Villa, Francisco

    1990-12-01

    A method to obtain accurate thickness data to characterize the emission patterns of evaporation sources is described. Thickness data is obtained through digital image processing algorithms applied to the monochromatic transmission bands digitized from a set of multilayer Fabry-Perot filters deposited on large flat circular substrates. These computer image-processed taper-thickness patterns are reduced to orthonormal polynomial series expansions in two steps, using Tschebyshev and associated Legendre polynomials. The circular glass substrates employed to characterize each type of evaporation source are kept stationary during the evaporation process of evaporation of each layer to obtain the specific thickness distribution for each type of source.

  3. Modeling study of natural emissions, source apportionment, and emission control of atmospheric mercury

    NASA Astrophysics Data System (ADS)

    Shetty, Suraj K.

    ) and CAMNet (Canadian Atmospheric Mercury Measurement Network). The model estimated a total deposition of 474 Mg yr-1 to the CONUS (Contiguous United States) domain, with two-thirds being dry deposited. Reactive gaseous mercury contributed the most to 60% of deposition. Emission speciation distribution is a key factor for local deposition as contribution from large point sources can be as high as 75% near (< 100 km) the emission sources, indicating that emission reduction may result in direct deposition decrease near the source locations. Among the sources, BC contributes to about 68% to 91% of total deposition. Excluding the BC's contribution, EGU contributes to nearly 50% of deposition caused by CONUS emissions in the Northeast, Southeast and East Central regions, while emissions from natural processes are more important in the Pacific and West Central regions (contributing up to 40% of deposition). The modeling results implies that implementation of the new emission standards proposed by USEPA (United States Environmental Protection Agency) would significantly benefit regions that have larger contributions from EGU sources. Control of mercury emissions from coal combustion processes has attracted great attention due to its toxicity and the emission-control regulations and has lead to advancement in state-of-the-art control technologies that alleviate the impact of mercury on ecosystem and human health. This part of the work applies a sorption model to simulate adsorption of mercury in flue gases, onto a confined-bed of activated carbon. The model's performances were studied at various flue gas flow rates, inlet mercury concentrations and adsorption bed temperatures. The process simulated a flue gas, with inlet mercury concentration of 300 ppb, entering at a velocity of 0.3 m s-1 from the bottom into a fixed bed (inside bed diameter of 1 m and 3 m bed height; bed temperature of 25 °C) of activated carbon (particle size of 0.004 m with density of 0.5 g cm-3 and

  4. Krakow conference on low emissions sources: Proceedings

    SciTech Connect

    Pierce, B.L.; Butcher, T.A.

    1995-12-31

    The Krakow Conference on Low Emission Sources presented the information produced and analytical tools developed in the first phase of the Krakow Clean Fossil Fuels and Energy Efficiency Program. This phase included: field testing to provide quantitative data on missions and efficiencies as well as on opportunities for building energy conservation; engineering analysis to determine the costs of implementing pollution control; and incentives analysis to identify actions required to create a market for equipment, fuels, and services needed to reduce pollution. Collectively, these Proceedings contain reports that summarize the above phase one information, present the status of energy system management in Krakow, provide information on financing pollution control projects in Krakow and elsewhere, and highlight the capabilities and technologies of Polish and American companies that are working to reduce pollution from low emission sources. It is intended that the US reader will find in these Proceedings useful results and plans for control of pollution from low emission sources that are representative of heating systems in central and Eastern Europe. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  5. NMHC emissions from Asia: sources and transport

    NASA Astrophysics Data System (ADS)

    Shirai, T.; Blake, D. R.; Barletta, B.; Meinardi, S.; Rowland, F. S.; Chan, J. C.; Takegawa, N.; Kondo, Y.; Koike, M.; Kita, K.; Takigawa, M.; Kawakami, S.; Ogawa, T.

    2002-12-01

    Recent rapid industrialization and economic growth in Asia changed the industrial structure, land use, and people's lifestyle resulting in a dramatic change in the amount and composition of the gas emissions from Asia. Because emissions can be transported very rapidly once convected to the free troposphere, Asian emissions can affect both local and regional air quality and climate. To access the impact of changing emission from Asia, an airborne observation campaign PEACE (the Pacific Exploration of Asian Continental Emission) phase-A and B were conducted in January and April - May 2002, respectively, sponsored by NASDA (National Space Development Agency of Japan). The concentrations of NMHCs (nonmethanehydrocarbons) and halocarbons were obtained by whole air sampling and subsequent gas chromatography analyses in the laboratory. Quantified onboard the aircraft were CO, CO2, O3, NO, NO2, NOy, H2O, SO2, aerosols, and condensation nuclei. The experiment was conducted in the vicinity of Japan and PEACE-A and B represent the local winter and spring weather conditions. The trace gas distributions in the lower troposphere were often influenced by local pollution (i.e. from Japan, Korea) while those of the long-range transport (i.e. from Europe) were occasionally seen in the upper troposphere. This is confirmed by the airmass age estimation using the ratios of short-lived gases (i.e. C2H4) vs. more stable compounds (i.e. CO). Emissions from China were distinguished using data obtained from ground-based sampling and measurements. Transport from China was seen both in the lower troposphere and upper troposphere. Some case studies on source identification will be discussed.

  6. VOC emission rates and emission factors for a sheetfed offset printing shop.

    PubMed

    Wadden, R A; Scheff, P A; Franke, J E; Conroy, L M; Javor, M; Keil, C B; Milz, S A

    1995-04-01

    Emission rates were determined during production for a sheetfed offset printing shop by combining the measured concentrations and ventilation rates with mass balance models that characterized the printing space. Air samples were collected simultaneously on charcoal tubes for 12 separate 1-hour periods at 6 locations. Air samples and cleaning solvents were analyzed by gas chromatography for total volatile organic compounds (VOC) and 13 hydrocarbons. The average VOC emission rate was 470 g/hr with a range of 160-1100 g/hr. These values were in good agreement with the amounts of VOC, hexane, toluene, and aromatic C9s determined from estimated solvent usage and measured solvent compositions. Comparison of the emission rates with source activities indicated an emission factor of 30-51 g VOC/press cleaning. Based on the test observations it was estimated that this typical small printing facility was likely to release 1-2 T VOC/year. The methodology also may be useful for the surface coating industry, as emission rates in this study were determined without recourse to a temporary total enclosure and without interfering with worker activities, increasing worker exposure, or increasing safety and explosion hazards.

  7. Framework for Assessing Biogenic CO2 Emissions from Stationary Sources

    EPA Science Inventory

    This revision of the 2011 report, Accounting Framework for Biogenic CO2 Emissions from Stationary Sources, evaluates biogenic CO2 emissions from stationary sources, including a detailed study of the scientific and technical issues associated with assessing biogenic carbon dioxide...

  8. Measuring Greenhouse-Gas Emissions from a Synthetic Tracer Source

    NASA Astrophysics Data System (ADS)

    Wang, W.; Liu, W.; Zhang, T.; Lu, Y.

    2014-05-01

    This paper describes a controlled tracer-release experiment in which methane was released from a synthetic source at known rates. An open-path Fourier transform infrared (OP-FTIR) spectroscopy system was used to measure line-averaged methane concentrations downwind of the source. A Lagrangian stochastic (LS) dispersion model was employed to infer emission rates from downwind gas concentrations. The main purpose of our study was to investigate the ability of our open-path FTIR system combined with the LS dispersion model to accurately measure greenhouse gas emissions. In our study, the average ratio of the estimated emissions to actual release rates QLS/Q for CH4 was about 0.86 (σQLS/Q = 0.2, n = 6) and 0.84 (σQLS/Q = 0.22, n = 3) after data fi ltering for a 15- and a 30- min period, respectively. Although there is a limited amount of data in this experiment, the results demonstrate the potential of the measurement system for accurate quantifi cation of greenhouse gas emissions.

  9. Denitrification as a Source of NO Emissions using Isotope Techniques

    NASA Astrophysics Data System (ADS)

    Cardenas, Laura; Loick, Nadine; Abalos, Diego; Dixon, Liz; Vallejo, Antonio; Watson, Catherine; McGeough, Karen; Well, Reinhard; Matthews, Peter

    2015-04-01

    Agricultural soils are a major source of nitric- (NO) and nitrous oxide (N2O) which are produced and consumed by biotic and abiotic soil processes. The dominant sources of NO and N2O are microbial nitrification and denitrification. Depending on the environmental conditions such as substrate availability, pH and water filled pore space (WFPS) N2O emissions have been attributed to both processes, whereas NO emissions are thought to predominantly derive from nitrification. This is due to the fact that the environmental factors which promote denitrifying conditions also restrict gaseous diffusivity causing consumption of the highly reactive NO. Recent findings however challenge this assumption indicating that denitrification can be a significant source of NO. Attributing gaseous emissions to specific soil processes is still difficult; however, advanced isotopic methods show great potential. Labelling methods rely on the use of 15N enriched substrates, whereas isotopomer analyses rely on differences in the utilisation of heavy vs light N and O isotopes at natural abundance. The present study analysed the effect of different enrichment levels on gaseous emissions using the gas-flow-soil-core technique (Cardenas et al 2003). This system provides continuous measurements of NO, N2O as well as N2 fluxes by exchanging the normal atmosphere with a mixture of He:O2 (80:20). This was combined with 15N labelled isotopic techniques and isotopomer measurements to determine the source and processes responsible for the measured N-emissions. Nutrient solutions were applied containing KNO3 with 15N at natural abundance, 5 atom% and 20 atom% enrichment at a rate of 75 kg N ha-1 together with glucose at a rate of 400 kg C ha-1. Results showed that at the higher level of enrichment gaseous emissions were affected by showing an increase in emissions of NO and N2O. Additionally, under denitrifying conditions (high WFPS and NO3- availability) denitrification played a key role in NO emissions

  10. Source gases: Concentrations, emissions, and trends

    NASA Technical Reports Server (NTRS)

    Fraser, Paul J.; Harriss, Robert; Penkett, Stuart A.; Makide, Yoshihiro; Sanhueza, Eugenio; Alyea, Fred N.; Rowland, F. Sherwood; Blake, Don; Sasaki, Toru; Cunnold, Derek M.

    1991-01-01

    Source gases are defined as those gases that influence levels of stratospheric ozone (O3) by transporting species containing halogen, hydrogen, and nitrogen to the stratosphere. Examples are the CFC's, methane (CH4), and nitrous oxide (N2O). Other source gases that also come under consideration in an atmospheric O3 context are those that are involved in the O3 or hydroxyl (OH) radical chemistry of the troposphere. Examples are CH4, carbon monoxide (CO), and nonmethane hydrocarbons (NMHC's). Most of the source gases, along with carbon dioxide (CO2) and water vapor (H2O), are climatically significant and thus affect stratospheric O3 levels by their influence on stratospheric temperatures. Carbonyl sulphide (COS) could affect stratospheric O3 through maintenance of the stratospheric sulphate aerosol layer, which may be involved in heterogeneous chlorine-catalyzed O3 destruction. The previous reviews of trends and emissions of source gases, either from the context of their influence on atmospheric O3 or global climate change, are updated. The current global abundances and concentration trends of the trace gases are given in tabular format.

  11. Source characteristics of Jovian hectometric radio emissions

    NASA Technical Reports Server (NTRS)

    Reiner, M. J.; Fainberg, J.; Stone, R. G.

    1993-01-01

    Direct confirmation that low-frequency Jovian hectometric (HOM) radio emissions centered near 0 deg central meridian longitude consist of distinct, oppositely polarized northern and southern beams has been achieved using data from the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in early February 1992. Distinct northern and southern beams were observed in the frequency range from approximately 300 kHz to 1 MHz for at least eight Jovian rotations during the Ulysses inbound pass at distances from 100 to 40 R(sub j). The radiation from the two magnetic hemispheres was measured from different Jovigraphic longitudes and magnetic (or centrifugal) latitudes. Observed temporal variations in the radio intensities, with time scales on the order of 30 min, may result either from longitudinal variations of the HOM sources or from longitudinal density variations in the Io plasma torus. Using the URAP direction-finding capabilities and assuming a tilted dipole planetary magnetic field model, the three-dimensional HOM source locations, the L shell through these source locations, and the beam opening angles were independently deduced. The HOM sources were found to originate at approximately 3 R(sub j) and on low L shells (L approximately 4 to 6), with beam opening angles ranging from 10 to 50 deg.

  12. 40 CFR 74.24 - Current allowable SO2 emissions rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Current allowable SO2 emissions rate... PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.24 Current allowable SO2 emissions rate. The designated representative shall submit the following data: (a)...

  13. GAMMA DOSE RATE NEAR A NEW (252)Cf BRACHYTHERAPY SOURCE

    SciTech Connect

    Fortune, Eugene C; Gauld, Ian C; Wang, C

    2011-01-01

    A new generation of medical grade (252)Cf sources was developed in 2002 at the Oak Ridge National Laboratory. The combination of small size and large activity of (252)Cf makes the new source suitable to be used with the conventional high-dose-rate remote afterloading system for interstitial brachytherapy. A recent in-water calibration experiment showed that the measured gamma dose rates near the new source are slightly greater than the neutron dose rates, contradicting the well established neutron-to-gamma dose ratio of approximately 2:1 at locations near a (252)Cf brachytherapy source. Specifically, the MCNP-predicted gamma dose rate is a factor of two lower than the measured gamma dose rate at the distance of I cm, and the differences between the two results gradually diminish at distances farther away from the source. To resolve this discrepancy, we updated the source gamma spectrum by including in the ORIGEN-S data library the experimentally measured (252)Cf prompt gamma spectrum as well as the true (252)Cf spontaneous fission yield data to explicitly model delayed gamma emissions from fission products. We also investigated the bremsstrahlung X-rays produced by the beta particles emitted from fission product decays. The results show that the discrepancy of gamma dose rates is mainly caused by the omission of the bremsstrahlung X-rays in the MCNP runs. By including the bremsstrahlung X-rays, the MCNP results show that the gamma dose rates near a new (252)Cf source agree well with the measured results and that the gamma dose rates are indeed greater than the neutron dose rates.

  14. Constraining Emission Models of Luminous Blazar Sources

    SciTech Connect

    Sikora, Marek; Stawarz, Lukasz; Moderski, Rafal; Nalewajko, Krzysztof; Madejski, Greg; /KIPAC, Menlo Park /SLAC

    2009-10-30

    Many luminous blazars which are associated with quasar-type active galactic nuclei display broad-band spectra characterized by a large luminosity ratio of their high-energy ({gamma}-ray) and low-energy (synchrotron) spectral components. This large ratio, reaching values up to 100, challenges the standard synchrotron self-Compton models by means of substantial departures from the minimum power condition. Luminous blazars have also typically very hard X-ray spectra, and those in turn seem to challenge hadronic scenarios for the high energy blazar emission. As shown in this paper, no such problems are faced by the models which involve Comptonization of radiation provided by a broad-line-region, or dusty molecular torus. The lack or weakness of bulk Compton and Klein-Nishina features indicated by the presently available data favors production of {gamma}-rays via up-scattering of infrared photons from hot dust. This implies that the blazar emission zone is located at parsec-scale distances from the nucleus, and as such is possibly associated with the extended, quasi-stationary reconfinement shocks formed in relativistic outflows. This scenario predicts characteristic timescales for flux changes in luminous blazars to be days/weeks, consistent with the variability patterns observed in such systems at infrared, optical and {gamma}-ray frequencies. We also propose that the parsec-scale blazar activity can be occasionally accompanied by dissipative events taking place at sub-parsec distances and powered by internal shocks and/or reconnection of magnetic fields. These could account for the multiwavelength intra-day flares occasionally observed in powerful blazars sources.

  15. Emission of polycyclic aromatic hydrocarbons and their carcinogenic potencies from cooking sources to the urban atmosphere.

    PubMed Central

    Li, Chun-The; Lin, Yuan-Chung; Lee, Wen-Jhy; Tsai, Perng-Jy

    2003-01-01

    Traffic has long been recognized as the major contributor to polycyclic aromatic hydrocarbon (PAH) concentrations. However, this does not consider the contribution of cooking sources of PAHs. This study set out, first, to assess the characteristics of PAHs and their corresponding benzo[a]pyrene equivalent (B[a]Peq) emissions from cooking sources to the urban atmosphere. To illustrate the importance of cooking sources, PAH emissions from traffic sources were then calculated and compared. The entire study was conducted on a city located in southern Taiwan. PAH samples were collected from the exhaust stacks of four types of restaurant: Chinese, Western, fast food, and Japanese. For total PAHs, results show that the fractions of gaseous PAHs (range, 75.9-89.9%) were consistently higher than the fractions of particulate PAHs (range, 10.1-24.1%) in emissions from the four types of restaurant. But for total B[a]Peq, we found that the contributions of gaseous PAHs (range, 15.7-21.9%) were consistently lower than the contributions of particulate PAHs (range, 78.1-84.3%). For emission rates of both total PAHs and total B[a]Peq, a consistent trend was found for the four types of restaurant: Chinese (2,038 and 154 kg/year, respectively) > Western (258 and 20.4 kg/year, respectively) > fast food (31.4 and 0.104 kg/year, respectively) > Japanese (5.11 and 0.014 kg/year, respectively). By directly adapting the emission data obtained from Chinese restaurants, we found that emission rates on total PAHs and total B[a]Peq for home kitchen sources were 6,639 and 501 kg/year, respectively. By combining both restaurant sources and home kitchen sources, this study yielded emission rates of total PAHs and total B[a]Peq from cooking sources of the studied city of 8,973 and 675 kg/year, respectively. Compared with PAH emissions from traffic sources in the same city, we found that although the emission rates of total PAHs for cooking sources were significantly less than those for traffic

  16. Emissivity Tuned Emitter for RTPV Power Sources

    SciTech Connect

    Carl M. Stoots; Robert C. O'Brien; Troy M. Howe

    2012-03-01

    Every mission launched by NASA to the outer planets has produced unexpected results. The Voyager I and II, Galileo, and Cassini missions produced images and collected scientific data that totally revolutionized our understanding of the solar system and the formation of the planetary systems. These missions were enabled by the use of nuclear power. Because of the distances from the Sun, electrical power was produced using the radioactive decay of a plutonium isotope. Radioisotopic Thermoelectric Generators (RTGs) used in the past and currently used Multi-Mission RTGs (MMRTGs) provide power for space missions. Unfortunately, RTGs rely on thermocouples to convert heat to electricity and are inherently inefficient ({approx} 3-7% thermal to electric efficiency). A Radioisotope Thermal Photovoltaic (RTPV) power source has the potential to reduce the specific mass of the onboard power supply by increasing the efficiency of thermal to electric conversion. In an RTPV, a radioisotope heats an emitter, which emits light to a photovoltaic (PV) cell, which converts the light into electricity. Developing an emitter tuned to the desired wavelength of the photovoltaic is a key part in increasing overall performance. Researchers at the NASA Glenn Research Center (GRC) have built a Thermal Photovoltaic (TPV) system, that utilizes a simulated General Purpose Heat Source (GPHS) from a MMRTG to heat a tantalum emitter. The GPHS is a block of graphite roughly 10 cm by 10 cm by 5 cm. A fully loaded GPHS produces 250 w of thermal power and weighs 1.6 kgs. The GRC system relies on the GPHS unit radiating at 1200 K to a tantalum emitter that, in turn, radiates light to a GaInAs photo-voltaic cell. The GRC claims system efficiency of conversion of 15%. The specific mass is around 167 kg/kWe. A RTPV power source that utilized a ceramic or ceramic-metal (cermet) matrix would allow for the combination of the heat source, canister, and emitter into one compact unit, and allow variation in size

  17. The Power Source(s) of Nearby Low-Ionization Nuclear Emission Regions

    NASA Astrophysics Data System (ADS)

    Molina, Mallory; Eracleous, Michael; Maoz, Dan; Barth, Aaron J.; Walsh, Jonelle; Ho, Luis C.; Shields, Joseph C.

    2015-01-01

    The majority of low-ionization nuclear emission regions (LINERs) harbor supermassive black holes (SMBHs) with very low accretion rates. Since SMBHs spend most of their lifetimes in these low-accretion rate states, understanding LINERs is important for understanding active galactic nuclei (AGN) in the context of galaxy evolution. On scales of ~100 pc, the energy budget of LINERs appears to be deficient when the only source of power considered is the AGN. Thus, other energy sources are likely to contribute to the excitation of the emission-line gas. To probe these sources, we observed three nearby, bright LINERs, NGC 1052, NGC 4278 and NGC 4579, with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). We specifically looked at the 0.1-1 arcsecond (corresponding to 5-50 pc) scale to find what and how far from the nucleus these other energy sources are. After subtracting both the unresolved nuclear light and the spatially-extended starlight, we measured a number of diagnostic emission line ratios. We find that line ratios, such as [O III]/[O II] and [O III]/H-beta change as a function of distance from the nucleus. Within 5 pc, the line ratios suggest AGN photoionization. At larger distances the line ratios seem to be inconsistent with AGN photoionization, but they appear to be consistent with excitation by hot stars or shocks.

  18. Mapping methane sources and emissions over California from direct airborne flux and VOC source tracer measurements

    NASA Astrophysics Data System (ADS)

    Guha, A.; Misztal, P. K.; Peischl, J.; Karl, T.; Jonsson, H. H.; Woods, R. K.; Ryerson, T. B.; Goldstein, A. H.

    2013-12-01

    Quantifying the contributions of methane (CH4) emissions from anthropogenic sources in the Central Valley of California is important for validation of the statewide greenhouse gas (GHG) inventory and subsequent AB32 law implementation. The state GHG inventory is largely based on activity data and emission factor based estimates. The 'bottom-up' emission factors for CH4 have large uncertainties and there is a lack of adequate 'top-down' measurements to characterize emission rates. Emissions from non-CO2 GHG sources display spatial heterogeneity and temporal variability, and are thus, often, poorly characterized. The Central Valley of California is an agricultural and industry intensive region with large concentration of dairies and livestock operations, active oil and gas fields and refining operations, as well as rice cultivation all of which are known CH4 sources. In order to gain a better perspective of the spatial distribution of major CH4 sources in California, airborne measurements were conducted aboard a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of low-altitude and mixed layer airborne CH4 and CO2 measurements alongside coincident VOC measurements. Transects during eight unique flights covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. We report direct quantification of CH4 fluxes using real-time airborne Eddy Covariance measurements. CH4 and CO2 were measured at 1-Hz data rate using an instrument based on Cavity Ring Down Spectroscopy (CRDS) along with specific VOCs (like isoprene, methanol, acetone etc.) measured at 10-Hz using Proton Transfer Reaction Mass Spectrometer - Eddy Covariance (PTRMS-EC) flux system. Spatially resolved eddy covariance

  19. Estimating gas emissions from multiple sources using a backward Lagrangian stochastic model.

    PubMed

    Gao, Zhiling; Desjardins, Raymond L; van Haarlem, Ronald P; Flesch, Thomas K

    2008-11-01

    Manure storage tanks and animals in barns are important agricultural sources of methane. To examine the possibility of using an inverse dispersion technique based on a backward Lagrangian Stochastic (bLS) model to quantify methane (CH4) emissions from multiple on-farm sources, a series of tests were carried out with four possible source configurations and three controlled area sources. The simulated configurations were: (C1) three spatially separate ground-level sources, (C2) three spatially separate sources with wind-flow disturbance, (C3) three adjacent ground-level sources to simulate a group of adjacent sources with different emission rates, and (C4) a configuration with a ground level and two elevated sources. For multiple ground-level sources without flow obstructions (C1 and C3), we can use the condition number (K, the ratio of the uncertainty in the calculated emission rate to the uncertainty in the predicted ratio of concentration to emission rate) to evaluate the applicability of this inverse dispersion technique and a preliminary threshold of K <10 is recommended. For multiple sources with wind disturbance (C2) or an even more complex configuration including ground level and elevated sources (C4), a low kappa is not sufficient to provide reasonable discrete and total emission rates. The effect of flow obstructions can be neglected as long as the distance between the source and the measurement location is greater than approximately 10 times the height of the flow obstructions. This study shows that the bLS model has the potential to provide accurate discrete emission rates from multiple on-farm emissions of gases provided that certain conditions are met.

  20. RESEARCH ON EMISSIONS AND MITIGATION OF POP'S FROM COMBUSTION SOURCES

    EPA Science Inventory

    Chapter summarizes EPA's research on emissions and control of persistent organic pollutants (POPS) from combustion sources, with emphasis on source characterization and measurement, formation and destruction mechanisms, formation prevention, and flue gas cleaning. Laboratory exp...

  1. Atmospheric measurement of point source fossil CO2 emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Baisden, T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2014-05-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m above ground level. We also determined the surface CO2ff content averaged over several weeks from the 14C content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~ one week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14C sampling strategies.

  2. Atmospheric measurement of point source fossil fuel CO2 emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Baisden, W. T.; Brailsford, G.; Bromley, T.; Norris, M.; Zondervan, A.

    2013-11-01

    We use the Kapuni Gas Treatment Plant to examine methodologies for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes CO2 from locally extracted natural gas and vents that CO2 to the atmosphere, at a rate of ~0.1 Tg carbon per year. The plant is located in a rural dairy farming area, with no other significant CO2ff sources nearby, but large, diurnally varying, biospheric CO2 fluxes from the surrounding highly productive agricultural grassland. We made flask measurements of CO2 and 14CO2 (from which we derive the CO2ff component) and in situ measurements of CO2 downwind of the Kapuni plant, using a Helikite to sample transects across the emission plume from the surface up to 100 m a.g.l. We also determined the surface CO2ff content averaged over several weeks from the 14CO2 content of grass samples collected from the surrounding area. We use the WindTrax plume dispersion model to compare the atmospheric observations with the emissions reported by the Kapuni plant, and to determine how well atmospheric measurements can constrain the emissions. The model has difficulty accurately capturing the fluctuations and short-term variability in the Helikite samples, but does quite well in representing the observed CO2ff in 15 min averaged surface flask samples and in ~1 week integrated CO2ff averages from grass samples. In this pilot study, we found that using grass samples, the modeled and observed CO2ff emissions averaged over one week agreed to within 30%. The results imply that greater verification accuracy may be achieved by including more detailed meteorological observations and refining 14CO2 sampling strategies.

  3. REGIONAL ASSESSMENT OF METHANE EMISSION RATES FROM RESERVOIRS IN THE MIDWESTERN UNITED STATES

    EPA Science Inventory

    Reservoirs are a globally significant source of methane (CH4) to the atmosphere, but regional and global emission estimates are poorly constrained due to high variability in emission rates among reservoirs and a lack of measurements in some areas geographic areas. Methane emissi...

  4. N-bursty emission from Uranus: A cyclotron maser source?

    NASA Technical Reports Server (NTRS)

    Curran, D. B.; Menietti, J. D.

    1993-01-01

    Ray tracing studies of RX-mode emission from the north polar regions of Uranus indicate that the n-bursty radio emission may have a source along field lines with footprints near the northern magnetic pole (perhaps in the cusp), but not necessarily associated with regions of strong UV emission. This is in contrast with similar studies for the Uranus nightside smooth radio emission, which are believed to be due to the cyclotron maser instability. Source regions can be found for both hollow and filled emission cones and for frequencies well above the local gyrofreuquency implying that mechanisms other than the cyclotron maser mechanism may be operating.

  5. Locating and estimating air emissions from sources of epichlorohydrin

    SciTech Connect

    Not Available

    1985-09-01

    To assist groups interested in inventorying air emissions of various potentially toxic substances, EPA is preparing a series of documents such as this to compile available information on sources and emissions of these substances. This document deals specifically with epichlorohydrin. Its intended audience includes Federal, State and local air pollution personnel and others interested in locating potential emitters of epichlorohydrin in making gross estimates of air emissions therefrom. This document presents information on 1) the types of sources that may emit epichlorohydrin; 2) process variations and release points that may be expected within these sources; and 3) available emissions information indicating the potential for epichlorohydrin release into the air from each operation.

  6. Area Source Emission Measurements Using EPA OTM 10

    EPA Science Inventory

    Measurement of air pollutant emissions from area and non-point sources is an emerging environmental concern. Due to the spatial extent and non-homogenous nature of these sources, assessment of fugitive emissions using point sampling techniques can be difficult. To help address th...

  7. Source sampling of particulate matter emissions from cotton harvesting - System field testing and emission factor development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emission factors are used in the air pollution regulatory process to quantify the mass of pollutants emitted from a source. Accurate emission factors must be used in the air pollution regulatory process to ensure fair and appropriate regulation for all sources. Agricultural sources, including cotton...

  8. Statistics of Isolated Emission Sources in Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Tappert, C.; Hanuschik, R.

    The strong emission lines in cataclysmic variables are the primary source of information on physical parameters of and the accretion process in these systems. Many examples show that the lines are composed not only from (symmetrical) disc emission, but that additional contribution is provided by isolated, i.e. asymmetric emission sources, distorting the original line profile. In this paper, we study the distribution of these additional components with several system parameters.

  9. High dose rate brachytherapy source measurement intercomparison.

    PubMed

    Poder, Joel; Smith, Ryan L; Shelton, Nikki; Whitaker, May; Butler, Duncan; Haworth, Annette

    2017-03-24

    This work presents a comparison of air kerma rate (AKR) measurements performed by multiple radiotherapy centres for a single HDR (192)Ir source. Two separate groups (consisting of 15 centres) performed AKR measurements at one of two host centres in Australia. Each group travelled to one of the host centres and measured the AKR of a single (192)Ir source using their own equipment and local protocols. Results were compared to the (192)Ir source calibration certificate provided by the manufacturer by means of a ratio of measured to certified AKR. The comparisons showed remarkably consistent results with the maximum deviation in measurement from the decay-corrected source certificate value being 1.1%. The maximum percentage difference between any two measurements was less than 2%. The comparisons demonstrated the consistency of well-chambers used for (192)Ir AKR measurements in Australia, despite the lack of a local calibration service, and served as a valuable focal point for the exchange of ideas and dosimetry methods.

  10. 40 CFR 1036.530 - Calculating greenhouse gas emission rates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Calculating greenhouse gas emission rates. 1036.530 Section 1036.530 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Procedures § 1036.530 Calculating greenhouse gas emission rates. This section describes how to...

  11. Registration for the Hanford Site: Sources of radioactive emissions

    SciTech Connect

    Silvia, M.J.

    1993-04-01

    This Registration Application serves to renew the registration for all Hanford Site sources of radioactive air emissions routinely reported to the State of Washington Department of Health (DOH). The current registration expires on August 15, 1993. The Application is submitted pursuant to the Washington Administrative Code (WAC) Chapter 246--247, and is consistent with guidance provided by DOH for renewal. The Application subdivides the Hanford Site into six major production, processing or research areas. Those six areas are in the 100 Area, 200 East Area, 200 West Area, 300 Area, 400 Area, and 600 Area. Each major group of point sources within the six areas listed above is represented by a Source Registration for Radioactive Air Emissions form. Annual emissions. for the sources are listed in the ``Radionuclide Air Emissions Report for the Hanford Site,`` published annually. It is a requirement that the following Statement of Compliance be provided: ``The radioactive air emissions from the above sources do meet the emissions standards contained in Chapter 173-480-040 WAC, Ambient Air Quality Standards and Emissions Limits for Radionuclides. As the Statement of Compliance pertains to this submittal, the phrase ``above sources`` is to be understood as meaning the combined air emissions from all sources registered by this submittal.

  12. Russia's black carbon emissions: focus on diesel sources

    NASA Astrophysics Data System (ADS)

    Kholod, Nazar; Evans, Meredydd; Kuklinski, Teresa

    2016-09-01

    Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25-30 % of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60 % of the on-road BC emissions, while cars represent only 5 % (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58 % of all diesel BC in Russia.

  13. Russia's black carbon emissions: focus on diesel sources

    SciTech Connect

    Kholod, Nazar; Evans, Meredydd; Kuklinski, Teresa

    2016-01-01

    Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25–30% of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60% of the on-road BC emissions, while cars represent only 5% (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58% of all diesel BC in Russia.

  14. Field Measurements of Isoprene and Monoterpene Emission Rates from Trees.

    NASA Astrophysics Data System (ADS)

    Dilts, Stephen Blair

    Monoterpene emission rates were measured by a branch enclosure technique from Pinus ponderosa in central Oregon in the early summer and fall along with photosynthesis and monoterpene needle concentrations. beta -pinene, Delta^3-carene, and alpha-pinene were the major constituents of the emissions with smaller amounts of myrcene, limonene, and beta-phellandrene. The emission rates of alpha-pinene and beta-pinene were highly correlated with their needle concentrations, while those of Delta ^3-carene were not. There was no discernible effect on emissions when photosynthesis was water stress limited in the fall, and monoterpene emissions appear to be distinct from short term photosynthetic carbon assimilation. Isoprene emission rates were measured from a Quercus robur on the Washington State University campus in the fall of 1989 and throughout the 1990 growing season, and from a Quercus rubra during most of the 1991 season and occasionally in 1992. The measured emission rates showed distinct seasonal patterns which could not be explained by temperature or light. Emission rates were initially low early in the season when the leaves were immature. Rates increased rapidly after leaf maturity to a maximum value and then declined over the rest of the season. Evidence suggests that the rate and magnitude of this decline depends on stresses on the tree. Isoprene emission rates were measured from several species near Oak Ridge, Tennessee. The mean normalized isoprene emission rate from the branch enclosure was compared to the rate measured from a Q. alba leaf in a light and temperature controlled cuvette. The branch enclosure result for Q. alba was about 65% lower than the mean leaf cuvette measurement. This difference appears be due to shading of leaves within the branch enclosure. A comparison was also made between the normalized branch enclosure results and normalized canopy isoprene flux measured by a micrometeorological gradient method with generally good agreement.

  15. Calculated emission rates for barium releases in space

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.

    1989-01-01

    The optical emissions from barium releases in space are caused by resonance and fluorescent scattering of sunlight. Emission rates for the dominant ion and neutral lines are calculated assuming the release to be optically thin and the barium to be in radiative equilibrium with the solar radiation. The solar spectrum has deep Fraunhofer absorption lines at the primary barium ion resonances. A velocity component toward or away from the sun will Doppler shift the emission lines relative to the absorption lines and the emission rates will increase many-fold over the rest value. The Doppler brightening is important in shaped charge or satellite releases where the barium is injected at high velocities. Emission rates as a function of velocity are calculated for the 4554, 4934, 5854, 6142 and 6497 A ion emission lines and the dominant neutral line at 5535 A. Results are presented for injection parallel to the ambient magnetic field, B, and for injection at an angle to B.

  16. Characterization of emissions from combustion sources: controlled studies

    SciTech Connect

    Tucker, W.G.

    1987-01-01

    This paper summarizes Session I papers (given at the EPA Workshop on Characterization of Contaminant Emissions from Indoor Sources, Chapel Hill, NC, May 1985) that illustrate the progress made to date on characterizing indoor-combustion emissions from unvented space heaters, gas appliances, and sidestream cigarette smoke. The state of knowledge of such emissions and their controllability is summarized by four general statements: (1) Unvented gas-fired appliances are important sources of indoor CO and NOx, but not of organic emissions; (2) Important combustion sources of indoor organics, include smoking and possibly kerosene heaters; (3) The extent of the problems of leakage from vented appliances is simply not known; (4) Indoor combustion sources do not appear to present major problems with controllability, if source removal is an acceptable alternative. From an engineering standpoint, the most-challenging issue is burner design changes for unvented appliances.

  17. Dust from southern Africa: rates of emission and biogeochemical properties

    NASA Astrophysics Data System (ADS)

    Bhattachan, A.; D'Odorico, P.; Zobeck, T. M.; Okin, G. S.; Dintwe, K.

    2012-12-01

    The stabilized linear dunefields in the southern Kalahari show signs of reactivation due to reduced vegetation cover owing to drought and/or overgrazing. It has been demonstrated with a laboratory dust generator that the southern Kalahari soils are good emitters of dust and that large-scale dune reactivation can potentially make the region an important dust source in the relatively low-dust Southern Hemisphere. We show that emergence of the southern Kalahari as a new dust source may affect ocean biogeochemistry as the soils are rich in soluble iron and the dust from the southern Kalahari commonly reaches the Southern Ocean. We investigate the biogeochemical properties of the fine fraction of soil from the Kalahari dunes and compare them to those of currently active dust sources such as the Makgadikgadi and the Etosha pans as well as other smaller pans in the region. Using field measurements of sediment fluxes and satellite images, we calculate the rates of dust emission from the southern Kalahari under different land cover scenarios. To assess the reversibility of dune reactivation in the southern Kalahari, we investigate the resilience of dunefield vegetation by looking at changes in soil nutrients, fine soil fractions, and seed bank in areas affected by intense denudation.

  18. [Odor emission rate of municipal solid waste from landfill working area].

    PubMed

    Qiang, Ning; Wang, Hong-Yu; Zhao, Ai-Hua; Yuan, Wen-Xiang; Tai, Jun; Chen, Meng

    2014-02-01

    Emission rates of volatile organic compounds (VOCs), H2S and odor unit from the surface of a municipal solid waste (MSW) landfill working area were measured with a wind tunnel sampler. The results show that the emission rate of odor from the non-point source of landfill is the function of environmental temperature and surface sweeping velocity. The emission rate measured in the high temperature season can be 6 times higher of that in the low temperature season. Within the experimental range of 0.6-4 m x s(-1) wind sweeping velocity, the emission rate shows a linear relationship with wind sweeping velocity. In summer, the emission rates of VOCs (measured by PID as isobutylene), H2S and odor unit are 385-680 microg x (m(2) x s)(-1), 4-7 microg x (m(2) x s)(-1), and 46.5-136 OU x (m(2) x s)(-1) respectively. The continuous sweeping experiment shows that the emission rate measured with clean air sweeping is the maximum possible emission rate, which needs to be adjusted when it is used to estimate the odor concentration of more than 10 min sample time or an area emission load.

  19. User access to the MAP3S source emissions inventory

    SciTech Connect

    Benkovitz, C M; Evans, V A

    1981-03-01

    An emissions inventory based on data obtained from the National Emissions Data System (NEDS), the Federal Power Commission (FPC), Environment Canada, and other agencies was compiled by the MAP3S Central Data Coordination at Brookhaven National Laboratory. Pertinent data was brought together, collated, and loaded into computerized data bases using SYSTEM 2000 as the data base management system. These data bases are available to interested users for interactive scanning or batch retrieval. The emissions inventory consists of two distinct sections: a point source inventory and an area source inventory. The point source inventory covers the continental US and Canada; information is kept at the individual source level. The area source inventory covers the continental US; information is kept on a county basis. Work is in progress to obtain a Canadian area source inventory based on census divisions.

  20. MICROBIAL VOLATILE ORGANIC COMPOUND EMISSION RATES AND EXPOSURE MODEL

    EPA Science Inventory

    This paper presents the results from a study that examined microbial volatile organic compound (MVOC) emissions from six fungi and one bacterial species (Streptomyces spp.) commonly found in indoor environments. Data are presented on peak emission rates from inoculated agar plate...

  1. Comparison of carbon emission and accumulation rates in sub-arctic lakes

    NASA Astrophysics Data System (ADS)

    Lundin, Erik; Bastviken, David; Klaminder, Jonatan; Olid Garcia, Carolina; Karlsson, Jan

    2013-04-01

    Lakes play an important role for the carbon cycling in the sub-arctic landscape by both storing carbon in sediments and by releasing carbon to the atmosphere. Still, our knowledge regarding the importance of carbon accumulation rates vs. carbon emissions in lakes is poor, restricting large scale assessment of source sink potential of lakes in the landscape. In this study we compare annual carbon accumulation rates and CO2 and CH4 emissions to the atmosphere for six Swedish subarctic lakes. We measured the partial pressure of CO2 (every second hour) during the ice free season. CH4 emissions were measured using floating chambers. Furthermore, we sampled sediment cores from each lake (one to three cores per lake depending on lakes sizes) and calculated the recent accumulation rate of carbon into sediments by dating each core, using 210Pb. Total annual carbon emissions (CO2 + CH4) ranged between 5 to 54 g C m-2 yr-1; hence, all lakes were atmospheric net sources of carbon. Carbon emissions were overall dominated by CO2 which made up to over 90 % of the total annual carbon emission in all lakes except one, having low CO2 emission, where CH4 counted for 40% of the annual carbon emission. Sediment carbon accumulation rates were of comparable magnitudes as the emissions, counting for rates of 30 to 60% of the total carbon emission to the atmosphere. This results stress the dual role of subarctic lakes as they are acting both as atmospheric sources of CO2 and CH4 and as significant storages of carbon in sediments.

  2. 40 CFR 63.1157 - Emission standards for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Facilities and Hydrochloric Acid Regeneration Plants § 63.1157 Emission standards for existing sources. (a... percent. (b) Hydrochloric acid regeneration plants. (1) No owner or operator of an existing affected...

  3. Effect of outside air ventilation rate on VOC concentrations and emissions in a call center

    SciTech Connect

    Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.; DiBartolomeo, D.L.; Russell, M.L.; Fisk, W.J.

    2002-01-01

    A study of the relationship between outside air ventilation rate and concentrations of VOCs generated indoors was conducted in a call center. Ventilation rates were manipulated in the building's four air handling units (AHUs). Concentrations of VOCs in the AHU returns were measured on 7 days during a 13-week period. Indoor minus outdoor concentrations and emission factors were calculated. The emission factor data was subjected to principal component analysis to identify groups of co-varying compounds based on source type. One vector represented emissions of solvents from cleaning products. Another vector identified occupant sources. Direct relationships between ventilation rate and concentrations were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.

  4. Ammonia emissions from non-agricultural sources in the UK

    NASA Astrophysics Data System (ADS)

    Sutton, M. A.; Dragosits, U.; Tang, Y. S.; Fowler, D.

    A detailed literature review has been undertaken of the magnitude of non-agricultural sources of ammonia (NH 3) in the United Kingdom. Key elements of the work included estimation of nitrogen (N) excreted by different sources (birds, animals, babies, human sweat), review of miscellaneous combustion sources, as well as identification of industrial sources and use of NH 3 as a solvent. Overall the total non-agricultural emission of NH 3 from the UK in 1996 is estimated here as 54 (27-106) kt NH 3-N yr -1, although this includes 11 (6-23) kt yr -1 from agriculture related sources (sewage sludge spreading, biomass burning and agro-industry). Compared with previous estimates for 1990, component source magnitudes have changed both because of revised average emissions per source unit (emission factors) and changes in the source activity between 1990 and 1996. Sources with larger average emission factors than before include horses, wild animals and sea bird colonies, industry, sugar beet processing, household products and non-agricultural fertilizer use, with the last three sources being included for the first time. Sources with smaller emission factors than before include: land spreading of sewage sludge, direct human emissions (sweat, breath, smoking, infants), pets (cats and dogs) and fertilizer manufacture. Between 1990 and 1996 source activities increased for sewage spreading (due to reduced dumping at sea) and transport (due to increased use of catalytic converters), but decreased for coal combustion. Combined with the current UK estimates of agricultural NH 3 emissions of 229 kt N yr -1 (1996), total UK NH 3 emissions are estimated at 283 kt N yr -1. Allowing for an import of reduced nitrogen (NH x) of 30 kt N yr -1 and deposition of 230 kt N yr -1, these figures imply an export of 83 kt NH 3-N yr -1. Although export is larger than previously estimated, due to the larger contribution of non-agricultural NH 3 emissions, it is still insufficient to balance the UK

  5. Atmospheric Verification of Point Source Fossil Fuel CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Norris, M. W.; Wiltshire, R.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.

    2015-12-01

    Large point sources (electricity generation and large-scale industry) make up roughly one third of all fossil fuel CO2 (CO2ff) emissions. Currently, these emissions are determined from self-reported inventory data, and sometimes from smokestack emissions monitoring, and the uncertainty in emissions from individual power plants is about 20%. We examine the utility of atmospheric 14C measurements combined with atmospheric transport modelling as a tool for independently quantifying point source CO2ff emissions, to both improve the accuracy of the reported emissions and for verification as we move towards a regulatory environment. We use the Kapuni Gas Treatment Facility as a test case. It is located in rural New Zealand with no other significant fossil fuel CO2 sources nearby, and emits CO2ff at ~0.1 Tg carbon per year. We use several different sampling methods to determine the 14C and hence the CO2ff content downwind of the emission source: grab flask samples of whole air; absorption of CO2 into sodium hydroxide integrated over many hours; and plant material which faithfully records the 14C content of assimilated CO2. We use a plume dispersion model to compare the reported emissions with our observed CO2ff mole fractions. We show that the short-term variability in plume dispersion makes it difficult to interpret the grab flask sample results, whereas the variability is averaged out in the integrated samples and we obtain excellent agreement between the reported and observed emissions, indicating that the 14C method can reliably be used to evaluated point source emissions.

  6. Photocathodes for High Repetition Rate Light Sources

    SciTech Connect

    Ben-Zvi, Ilan

    2014-04-20

    This proposal brought together teams at Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL) and Stony Brook University (SBU) to study photocathodes for high repetition rate light sources such as Free Electron Lasers (FEL) and Energy Recovery Linacs (ERL). Below details the Principal Investigators and contact information. Each PI submits separately for a budget through his corresponding institute. The work done under this grant comprises a comprehensive program on critical aspects of the production of the electron beams needed for future user facilities. Our program pioneered in situ and in operando diagnostics for alkali antimonide growth. The focus is on development of photocathodes for high repetition rate Free Electron Lasers (FELs) and Energy Recovery Linacs (ERLs), including testing SRF photoguns, both normal-­conducting and superconducting. Teams from BNL, LBNL and Stony Brook University (SBU) led this research, and coordinated their work over a range of topics. The work leveraged a robust infrastructure of existing facilities and the support was used for carrying out the research at these facilities. The program concentrated in three areas: a) Physics and chemistry of alkali-­antimonide cathodes (BNL – LBNL) b) Development and testing of a diamond amplifier for photocathodes (SBU -­ BNL) c) Tests of both cathodes in superconducting RF photoguns (SBU) and copper RF photoguns (LBNL) Our work made extensive use of synchrotron radiation materials science techniques, such as powder-­ and single-­crystal diffraction, x-­ray fluorescence, EXAFS and variable energy XPS. BNL and LBNL have many complementary facilities at the two light sources associated with these laboratories (NSLS and ALS, respectively); use of these will be a major thrust of our program and bring our understanding of these complex materials to a new level. In addition, CHESS at Cornell will be used to continue seamlessly throughout the NSLS dark period and

  7. Cumulative carbon emissions, emissions floors and short-term rates of warming: implications for policy.

    PubMed

    Bowerman, Niel H A; Frame, David J; Huntingford, Chris; Lowe, Jason A; Allen, Myles R

    2011-01-13

    A number of recent studies have found a strong link between peak human-induced global warming and cumulative carbon emissions from the start of the industrial revolution, while the link to emissions over shorter periods or in the years 2020 or 2050 is generally weaker. However, cumulative targets appear to conflict with the concept of a 'floor' in emissions caused by sectors such as food production. Here, we show that the introduction of emissions floors does not reduce the importance of cumulative emissions, but may make some warming targets unachievable. For pathways that give a most likely warming up to about 4°C, cumulative emissions from pre-industrial times to year 2200 correlate strongly with most likely resultant peak warming regardless of the shape of emissions floors used, providing a more natural long-term policy horizon than 2050 or 2100. The maximum rate of CO(2)-induced warming, which will affect the feasibility and cost of adapting to climate change, is not determined by cumulative emissions but is tightly aligned with peak rates of emissions. Hence, cumulative carbon emissions to 2200 and peak emission rates could provide a clear and simple framework for CO(2) mitigation policy.

  8. Global inventory of volatile organic compound emissions from anthropogenic sources

    SciTech Connect

    Piccot, S.D.; Watson, J.J.; Jones, J.W.

    1992-01-01

    The paper discusses the development of a global inventory of anthropogenic volatile organic compound (VOC) emissions. It includes VOC estimates for seven classes of VOCs: paraffins, olefins, aromatics (benzene, toluene, xylene), formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds. These classes represent general classes of VOC compounds that possess different chemical reactivities in the atmosphere. The inventory shows total global anthropogenic VOC emissions of about 110,000 Gg/yr, about 10% lower than global VOC inventories developed by other researchers. The study identifies the U.S. as the largest emitter (21% of the total global VOC), followed by the USSR, China, India, and Japan. Globally, fuel wood combustion and savanna burning were among the largest VOC emission sources, accounting for over 35% of the total global VOC emissions. The production and use of gasoline, refuse disposal activities, and organic chemical and rubber manufacturing were also found to be significant sources of global VOC emissions.

  9. Source Emissions in Multipollutant Air Quality Management

    EPA Science Inventory

    Human activities and natural processes that emit pollutants into the ambient atmosphere are the underlying cause of all air quality problems. In a technical sense, we refer to these activities and processes as pollutant sources. Although air quality management is usually concerne...

  10. Spectra and rates of bremsstrahlung neutrino emission in stars

    NASA Astrophysics Data System (ADS)

    Guo, Gang; Qian, Yong-Zhong

    2016-08-01

    We calculate the energy-differential rate for neutrino emission from electron-nucleus bremsstrahlung in stellar interiors taking into account the effects of electron screening and ionic correlations. We compare the energy-differential and the net rates, as well as the average ν¯e and ν¯x(x =μ ,τ ) energies, for this process with those for e± pair annihilation, plasmon decay, and photoneutrino emission over a wide range of temperature and density. We also compare our updated energy loss rates for the above thermal neutrino emission processes with the fitting formulas widely used in stellar evolution models and determine the temperature and density domain in which each process dominates. We discuss the implications of our results for detection of ν¯e from massive stars during their presupernova evolution and find that pair annihilation makes the predominant contribution to the signal from the thermal emission processes.

  11. Effect of low emission sources on air quality in Cracow

    SciTech Connect

    Nedoma, J.

    1995-12-31

    The paper presents calculation of power engineering low emission and results of stimulation of the effect of this emission on air quality in Cracow, Poland. It has been stated that the segment of low emission in central areas of the town makes up ca. 40% of the observed concentration of sulfur dioxide. Furthermore it has been stated that the capital investment must be concentrated in the central part of the town in order to reach noticeable improvement of air quality in Cracow. Neither the output of a separate power source nor the emission level and its individual harmful effect, but the location of the source and especially packing density of the sources must decide the priority of upgrading actions.

  12. Classification of nutrient emission sources in the Vistula River system.

    PubMed

    Kowalkowski, Tomasz

    2009-06-01

    Eutrophication of the Baltic sea still remains one of the biggest problems in the north-eastern area of Europe. Recognizing the sources of nutrient emission, classification of their importance and finding the way towards reduction of pollution are the most important tasks for scientists researching this area. This article presents the chemometric approach to the classification of nutrient emission with respect to the regionalisation of emission sources within the Vistula River basin (Poland). Modelled data for mean yearly emission of nitrogen and phosphorus in 1991-2000 has been used for the classification. Seventeen subcatchements in the Vistula basin have been classified according to cluster and factor analyses. The results of this analysis allowed determination of groups of areas with similar pollution characteristics and indicate the need for spatial differentiation of policies and strategies. Three major factors indicating urban, erosion and agricultural sources have been identified as major discriminants of the groups.

  13. Aerostat-Lofted Instrument Platform and Sampling Method for Determination of Emissions from Open Area Sources

    EPA Science Inventory

    Sampling emissions from open area sources, particularly sources of open burning, is difficult due to fast dilution of emissions and safety concerns for personnel. Representative emission samples can be difficult to obtain with flaming and explosive sources since personnel safety ...

  14. Locating and quantifying gas emission sources using remotely obtained concentration data

    NASA Astrophysics Data System (ADS)

    Hirst, Bill; Jonathan, Philip; González del Cueto, Fernando; Randell, David; Kosut, Oliver

    2013-08-01

    We describe a method for detecting, locating and quantifying sources of gas emissions to the atmosphere using remotely obtained gas concentration data; the method is applicable to gases of environmental concern. We demonstrate its performance using methane data collected from aircraft. Atmospheric point concentration measurements are modelled as the sum of a spatially and temporally smooth atmospheric background concentration, augmented by concentrations due to local sources. We model source emission rates with a Gaussian mixture model and use a Markov random field to represent the atmospheric background concentration component of the measurements. A Gaussian plume atmospheric eddy dispersion model represents gas dispersion between sources and measurement locations. Initial point estimates of background concentrations and source emission rates are obtained using mixed ℓ2 - ℓ1 optimisation over a discretised grid of potential source locations. Subsequent reversible jump Markov chain Monte Carlo inference provides estimated values and uncertainties for the number, emission rates and locations of sources unconstrained by a grid. Source area, atmospheric background concentrations and other model parameters, including plume model spreading and Lagrangian turbulence time scale, are also estimated. We investigate the performance of the approach first using a synthetic problem, then apply the method to real airborne data from a 1600 km2 area containing two landfills, then a 225 km2 area containing a gas flare stack.

  15. WORKSHOP ON SOURCE EMISSION AND AMBIENT AIR MONITORING OF MERCURY

    EPA Science Inventory

    AN EPA/ORD Workshop on Source Emission and Ambient Air Monitoring of Mercury was held on 9/13-14/99, Bloomington, Minnesota. The purpose of the workshop was to discuss the state-of-the-science in source and ambient air mercury monitoring as well as mercury monitoring research and...

  16. Neptune's non-thermal radio emissions - Phenomenology and source locations

    NASA Technical Reports Server (NTRS)

    Rabl, Gerald K. F.; Ladreiter, H.-P.; Rucker, Helmut O.; Kaiser, Michael L.

    1992-01-01

    During the inbound and the outbound leg of Voyager 2's encounter with Neptune, the Planetary Radio Astronomy (PRA) experiment aboard the spacecraft detected short radio bursts at frequencies within the range of about 500-1300 kHz, and broad-banded smoothly varying emission patterns within the frequency range from about 40-800 kHz. Both emissions can be described in terms of a period of 16.1 hours determining Neptune's rotation period. Furthermore, just near closest approach, a narrow-banded smoothly varying radio component was observed occurring between 600 and 800 kHz. After giving a brief overview about some general characteristics of Neptune's nonthermal radio emission, the source locations of Neptune's emission components are determined, using an offset tilted dipole model for Neptune's magnetic field. Assuming that the emission originates near the electron gyrofrequency a geometrical beaming model is developed in order to fit the observed emission episodes.

  17. Quantification of Methane Source Locations and Emissions in AN Urban Setting

    NASA Astrophysics Data System (ADS)

    Crosson, E.; Richardson, S.; Tan, S. M.; Whetstone, J.; Bova, T.; Prasad, K. R.; Davis, K. J.; Phillips, N. G.; Turnbull, J. C.; Shepson, P. B.; Cambaliza, M. L.

    2011-12-01

    The regulation of methane emissions from urban sources such as landfills and waste-water treatment facilities is currently a highly debated topic in the US and in Europe. This interest is fueled, in part, by recent measurements indicating that urban emissions are a significant source of Methane (CH4) and in fact may be substantially higher than current inventory estimates(1). As a result, developing methods for locating and quantifying emissions from urban methane sources is of great interest to industries such as landfill and wastewater treatment facility owners, watchdog groups, and the governmental agencies seeking to evaluate or enforce regulations. In an attempt to identify major methane source locations and emissions in Boston, Indianapolis, and the Bay Area, systematic measurements of CH4 concentrations and meteorology data were made at street level using a vehicle mounted cavity ringdown analyzer. A number of discrete sources were detected at concentration levels in excess of 15 times background levels. Using Gaussian plume models as well as tomographic techniques, methane source locations and emission rates will be presented. In addition, flux chamber measurements of discrete sources such as those found in natural gas leaks will also be presented. (1) Wunch, D., P.O. Wennberg, G.C. Toon, G. Keppel-Aleks, and Y.G. Yavin, Emissions of Greenhouse Gases from a North American Megacity, Geophysical Research Letters, Vol. 36, L15810, doi:10.1029/2009GL)39825, 2009.

  18. Influence of light and temperature on monoterpene emission rates from slash pine

    SciTech Connect

    Tingey, D.T.; Manning, M.; Grothaus, L.C.; Burns, W.F.

    1980-05-01

    There is a growing awareness of vegetation's role as a source of potentially reactive hydrocarbons that may serve as photochemical oxidant precursors. This study assessed the influence of light and temperature, independently, on monoterpene emissions from slash pine (Pinus elliottii Engelm). Plants were preconditioned in0a growth chamber, then transferred to an environmentally controlled gas exchange chamber. Samples of the chamber atmosphere were collected; the monoterpenes were concentrated cryogenically and measured by gas chromatography. Five monoterpenes (..cap alpha..-pinene, ..beta..-pinene, myrcene, limonene, and ..beta..-phellandrene) were present in the vapor phase surrounding the plants in sufficient quantity for reliable measurement. Light did not directly influence monoterpene emission rates since the emissions were similar in both the dark and at various light intensities. Monoterpene emission rates increased exponentially with temperature (i.e. emissions depend on temperature in a log-linear manner). The summed emissions of the five monoterpenes ranged from 3 to 21 micrograms C per grams dry weight per hour as temperature was increased from 20 to 46 C. Initially, emission rates from heat-stressed needles were similar to healthy needles, but rates decreased 11% per day. Daily carbon loss through monoterpene emissions accounted for approximately 0.4% of the carbon fixed during photosynthesis.

  19. Pulsed, atmospheric pressure plasma source for emission spectrometry

    DOEpatents

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2004-05-11

    A low-power, plasma source-based, portable molecular light emission generator/detector employing an atmospheric pressure pulsed-plasma for molecular fragmentation and excitation is described. The average power required for the operation of the plasma is between 0.02 W and 5 W. The features of the optical emission spectra obtained with the pulsed plasma source are significantly different from those obtained with direct current (dc) discharge higher power; for example, strong CH emission at 431.2 nm which is only weakly observed with dc plasma sources was observed, and the intense CN emission observed at 383-388 nm using dc plasma sources was weak in most cases. Strong CN emission was only observed using the present apparatus when compounds containing nitrogen, such as aniline were employed as samples. The present apparatus detects dimethylsulfoxide at 200 ppb using helium as the plasma gas by observing the emission band of the CH radical. When coupled with a gas chromatograph for separating components present in a sample to be analyzed, the present invention provides an apparatus for detecting the arrival of a particular component in the sample at the end of the chromatographic column and the identity thereof.

  20. Volatile organic compound concentrations and emission rates in new manufactured and site-built houses.

    PubMed

    Hodgson, A T; Rudd, A F; Beal, D; Chandra, S

    2000-09-01

    Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2-9.5 months following installation and in seven new site-built houses 1-2 months after completion. The houses were in four projects located in hot-humid and mixed-humid climates. They were finished and operational, but unoccupied. Ventilation rates ranged from 0.14-0.78 h-1. Several of the site-built houses had ventilation rates below the ASHRAE recommended value. In both manufactured and site-built houses, the predominant airborne compounds were alpha-pinene, formaldehyde, hexanal, and acetic acid. Formaldehyde concentrations were below or near 50 ppb with a geometric mean value for all houses of 40 ppb. Similarities in the types of VOCs and in VOC concentrations indicated that indoor air quality in the houses was impacted by the same or similar sources. Major identified sources included plywood flooring, latex paint and sheet vinyl flooring. One site-built house was operated at ventilation rates of 0.14 and 0.32 h-1. VOC emission rates calculated at the two conditions agreed within +/- 10% for the most volatile compounds. Generally, the ratios of emission rates at the low and high ventilation rates decreased with decreasing compound volatility. Changes in VOC emission rates in the manufactured houses over 2-9.5 months after installation varied by compound. Only several compounds showed a consistent decrease in emission rate over this period.

  1. Aircraft-Based Measurements of Point Source Methane Emissions in the Barnett Shale Basin.

    PubMed

    Lavoie, Tegan N; Shepson, Paul B; Cambaliza, Maria O L; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Yacovitch, Tara I; Herndon, Scott C; Lan, Xin; Lyon, David

    2015-07-07

    We report measurements of methane (CH4) emission rates observed at eight different high-emitting point sources in the Barnett Shale, Texas, using aircraft-based methods performed as part of the Barnett Coordinated Campaign. We quantified CH4 emission rates from four gas processing plants, one compressor station, and three landfills during five flights conducted in October 2013. Results are compared to other aircraft- and surface-based measurements of the same facilities, and to estimates based on a national study of gathering and processing facilities emissions and 2013 annual average emissions reported to the U.S. EPA Greenhouse Gas Reporting Program (GHGRP). For the eight sources, CH4 emission measurements from the aircraft-based mass balance approach were a factor of 3.2-5.8 greater than the GHGRP-based estimates. Summed emissions totaled 7022 ± 2000 kg hr(-1), roughly 9% of the entire basin-wide CH4 emissions estimated from regional mass balance flights during the campaign. Emission measurements from five natural gas management facilities were 1.2-4.6 times larger than emissions based on the national study. Results from this study were used to represent "super-emitters" in a newly formulated Barnett Shale Inventory, demonstrating the importance of targeted sampling of "super-emitters" that may be missed by random sampling of a subset of the total.

  2. 40 CFR 63.1505 - Emission standards for affected sources and emission units.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... monitoring option. (f) Sweat furnace. The owner or operator of a sweat furnace shall comply with the emission... operator of a sweat furnace at a secondary aluminum production facility that is a major or area source...

  3. 40 CFR 63.1505 - Emission standards for affected sources and emission units.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... monitoring option. (f) Sweat furnace. The owner or operator of a sweat furnace shall comply with the emission... operator of a sweat furnace at a secondary aluminum production facility that is a major or area source...

  4. 40 CFR 63.1505 - Emission standards for affected sources and emission units.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... monitoring option. (f) Sweat furnace. The owner or operator of a sweat furnace shall comply with the emission... operator of a sweat furnace at a secondary aluminum production facility that is a major or area source...

  5. 40 CFR 63.1505 - Emission standards for affected sources and emission units.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... monitoring option. (f) Sweat furnace. The owner or operator of a sweat furnace shall comply with the emission... operator of a sweat furnace at a secondary aluminum production facility that is a major or area source...

  6. 40 CFR 63.1505 - Emission standards for affected sources and emission units.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... monitoring option. (f) Sweat furnace. The owner or operator of a sweat furnace shall comply with the emission... operator of a sweat furnace at a secondary aluminum production facility that is a major or area source...

  7. Control for NOx Emissions from Combustion Sources

    NASA Technical Reports Server (NTRS)

    PozodeFernandez, Maria E.; Collins, Michelle M.

    2000-01-01

    The Environmental Program Office at the Kennedy Space Center is interested in finding solutions and to promote research and development (R&D) that could contribute to solve the problems of air, soil, and groundwater contamination. This study is undertaken as part of NASA's environmental stewardship program. The objective of this study involves the removal of nitrogen oxides from the flue gases of the boilers at KSC using hydrogen peroxide. Phase 1 of this study have shown the potential of this process to be used as an alternative to the current methods of treatment used in the power industry. This report summarizes the research done during the ten-week summer program. During this period, support has been given to implement the modifications suggested for Phase 2 of the project, which focus on oxidation reactions carried at lower temperatures using an ultraviolet source. The redesign and assembly of the modifications for the scrubbing system was the main objective of this research.

  8. TRANSIT BUS LOAD-BASED MODAL EMISSION RATE MODEL DEVELOPMENT

    EPA Science Inventory

    Heavy-duty diesel vehicles (HDDVs) operations are a major source of oxides of nitrogen (NOx) and particulate matter (PM) emissions in metropolitan area nationwide. Although HD¬DVs constitute a small portion of the on-road fleet, they typically contribute more than 45% of NOx and ...

  9. Studies of acoustic emission from point and extended sources

    NASA Technical Reports Server (NTRS)

    Sachse, W.; Kim, K. Y.; Chen, C. P.

    1986-01-01

    The use of simulated and controlled acoustic emission signals forms the basis of a powerful tool for the detailed study of various deformation and wave interaction processes in materials. The results of experiments and signal analyses of acoustic emission resulting from point sources such as various types of indentation-produced cracks in brittle materials and the growth of fatigue cracks in 7075-T6 aluminum panels are discussed. Recent work dealing with the modeling and subsequent signal processing of an extended source of emission in a material is reviewed. Results of the forward problem and the inverse problem are presented with the example of a source distributed through the interior of a specimen.

  10. Emission rates of organics from vegetation in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Winer, Arthur M.; Arey, Janet; Atkinson, Roger; Aschmann, Sara M.; Long, William D.; Morrison, C. Lynn; Olszyk, David M.

    Rates of emission of speciated hydrocarbons have been determined for more than 30 of the most dominant (based on acreage) agricultural and natural plant types found in California's Central Valley. These measurements employed flow-through Teflon chambers, sample collection on solid adsorbent and thermal desorption gas chromatography (GC) and GC-mass spectrometry analysis to identify more than 40 individual organic compounds. In addition to isoprene and the monoterpenes, we observed sesquiterpenes, alcohols, acetates, aldehydes, ketones, ethers, esters, alkanes, alkenes and aromatics as emissions from these plant species. Mean emission rates for total monoterpenes ranged from none detected in the case of beans, grapes, rice and wheat, to as high as 12-30 μg h -1 g -1 for pistachio and tomato (normalized to dry leaf and total biomass, respectively). Other agricultural species exhibiting substantial rates of emission of monoterpenes included carrot, cotton, lemon, orange and walnut. All of the plant species studied showed total assigned compound emission rates in the range between 0.1 and 36 νg h -1 g -1.

  11. Monoterpene emission rate measurements from a Monterey pine

    SciTech Connect

    Juuti, S. ); Arey, J.; Atkinson, R. )

    1990-05-20

    The monoterpenes emitted from a Monterey pine (pinus radiata) were investigated using a dynamic flow-through enclosure technique. The monoterpenes identified and quantified were {alpha}- and {beta}-pinene, d-limonene + {beta} phellandrene, myrcene, camphene and {Delta}{sup 3}-carene, with {alpha}- and {beta}-pinene accounting for over 80% of the total monoterpene emissions. The monoterpene emission rate increased with temperature, in good agreement with previous data for other coniferous species. The absence of added CO{sub 2} to the synthetic air flow stream, exposure to elevated levels (300-500 ppb mixing ratio) of O{sub 3} for 3-4 hours, and increased air movement within the enclosure, had no observable effect on the monoterpene emission rate at a given temperature. In contrast, rough handling of the pine during the sampling protocol resulted in increases in the monoterpene emission rate by factors of 10-50. These results will be useful to those designing enclosure sampling protocols for the determination of the emission rates of biogenic organic compounds from vegetation.

  12. Discrimination of particulate matter emission sources using stochastic methods

    NASA Astrophysics Data System (ADS)

    Szczurek, Andrzej; Maciejewska, Monika; Wyłomańska, Agnieszka; Sikora, Grzegorz; Balcerek, Michał; Teuerle, Marek

    2016-12-01

    Particulate matter (PM) is one of the criteria pollutants which has been determined as harmful to public health and the environment. For this reason the ability to recognize its emission sources is very important. There are a number of measurement methods which allow to characterize PM in terms of concentration, particles size distribution, and chemical composition. All these information are useful to establish a link between the dust found in the air, its emission sources and influence on human as well as the environment. However, the methods are typically quite sophisticated and not applicable outside laboratories. In this work, we considered PM emission source discrimination method which is based on continuous measurements of PM concentration with a relatively cheap instrument and stochastic analysis of the obtained data. The stochastic analysis is focused on the temporal variation of PM concentration and it involves two steps: (1) recognition of the category of distribution for the data i.e. stable or the domain of attraction of stable distribution and (2) finding best matching distribution out of Gaussian, stable and normal-inverse Gaussian (NIG). We examined six PM emission sources. They were associated with material processing in industrial environment, namely machining and welding aluminum, forged carbon steel and plastic with various tools. As shown by the obtained results, PM emission sources may be distinguished based on statistical distribution of PM concentration variations. Major factor responsible for the differences detectable with our method was the type of material processing and the tool applied. In case different materials were processed by the same tool the distinction of emission sources was difficult. For successful discrimination it was crucial to consider size-segregated mass fraction concentrations. In our opinion the presented approach is very promising. It deserves further study and development.

  13. Independent evaluation of point source fossil fuel CO2 emissions to better than 10%

    PubMed Central

    Turnbull, Jocelyn Christine; Keller, Elizabeth D.; Norris, Margaret W.; Wiltshire, Rachael M.

    2016-01-01

    Independent estimates of fossil fuel CO2 (CO2ff) emissions are key to ensuring that emission reductions and regulations are effective and provide needed transparency and trust. Point source emissions are a key target because a small number of power plants represent a large portion of total global emissions. Currently, emission rates are known only from self-reported data. Atmospheric observations have the potential to meet the need for independent evaluation, but useful results from this method have been elusive, due to challenges in distinguishing CO2ff emissions from the large and varying CO2 background and in relating atmospheric observations to emission flux rates with high accuracy. Here we use time-integrated observations of the radiocarbon content of CO2 (14CO2) to quantify the recently added CO2ff mole fraction at surface sites surrounding a point source. We demonstrate that both fast-growing plant material (grass) and CO2 collected by absorption into sodium hydroxide solution provide excellent time-integrated records of atmospheric 14CO2. These time-integrated samples allow us to evaluate emissions over a period of days to weeks with only a modest number of measurements. Applying the same time integration in an atmospheric transport model eliminates the need to resolve highly variable short-term turbulence. Together these techniques allow us to independently evaluate point source CO2ff emission rates from atmospheric observations with uncertainties of better than 10%. This uncertainty represents an improvement by a factor of 2 over current bottom-up inventory estimates and previous atmospheric observation estimates and allows reliable independent evaluation of emissions. PMID:27573818

  14. Independent evaluation of point source fossil fuel CO2 emissions to better than 10.

    PubMed

    Turnbull, Jocelyn Christine; Keller, Elizabeth D; Norris, Margaret W; Wiltshire, Rachael M

    2016-09-13

    Independent estimates of fossil fuel CO2 (CO2ff) emissions are key to ensuring that emission reductions and regulations are effective and provide needed transparency and trust. Point source emissions are a key target because a small number of power plants represent a large portion of total global emissions. Currently, emission rates are known only from self-reported data. Atmospheric observations have the potential to meet the need for independent evaluation, but useful results from this method have been elusive, due to challenges in distinguishing CO2ff emissions from the large and varying CO2 background and in relating atmospheric observations to emission flux rates with high accuracy. Here we use time-integrated observations of the radiocarbon content of CO2 ((14)CO2) to quantify the recently added CO2ff mole fraction at surface sites surrounding a point source. We demonstrate that both fast-growing plant material (grass) and CO2 collected by absorption into sodium hydroxide solution provide excellent time-integrated records of atmospheric (14)CO2 These time-integrated samples allow us to evaluate emissions over a period of days to weeks with only a modest number of measurements. Applying the same time integration in an atmospheric transport model eliminates the need to resolve highly variable short-term turbulence. Together these techniques allow us to independently evaluate point source CO2ff emission rates from atmospheric observations with uncertainties of better than 10%. This uncertainty represents an improvement by a factor of 2 over current bottom-up inventory estimates and previous atmospheric observation estimates and allows reliable independent evaluation of emissions.

  15. TEST METHODS TO CHARACTERIZE PARTICULATE MATTER EMISSIONS AND DEPOSITION RATES IN A RESEARCH HOUSE

    EPA Science Inventory

    The paper discusses test methods to characterize particulate matter (PM) emissions and deposition rates in a research house. In a room in the research house, specially configured for PM source testing, a high-efficiency particulate air (HEPA)-filtered air supply system, used for...

  16. Vacuum cleaner emissions as a source of indoor exposure to airborne particles and bacteria.

    PubMed

    Knibbs, Luke D; He, Congrong; Duchaine, Caroline; Morawska, Lidia

    2012-01-03

    Vacuuming can be a source of indoor exposure to biological and nonbiological aerosols, although there are few data that describe the magnitude of emissions from the vacuum cleaner itself. We therefore sought to quantify emission rates of particles and bacteria from a large group of vacuum cleaners and investigate their potential determinants, including temperature, dust bags, exhaust filters, price, and age. Emissions of particles between 0.009 and 20 μm and bacteria were measured from 21 vacuums. Ultrafine (<100 nm) particle emission rates ranged from 4.0 × 10(6) to 1.1 × 10(11) particles min(-1). Emission of 0.54-20 μm particles ranged from 4.0 × 10(4) to 1.2 × 10(9) particles min(-1). PM(2.5) emissions were between 2.4 × 10(-1) and 5.4 × 10(3) μg min(-1). Bacteria emissions ranged from 0 to 7.4 × 10(5) bacteria min(-1) and were poorly correlated with dust bag bacteria content and particle emissions. Large variability in emission of all parameters was observed across the 21 vacuums, which was largely not attributable to the range of determinant factors we assessed. Vacuum cleaner emissions contribute to indoor exposure to nonbiological and biological aerosols when vacuuming, and this may vary markedly depending on the vacuum used.

  17. 2-.mu.m fiber amplified spontaneous emission (ASE) source

    NASA Technical Reports Server (NTRS)

    Jiang, Shibin (Inventor); Wu, Jianfeng (Inventor); Geng, Jihong (Inventor)

    2007-01-01

    A 2-.mu.m fiber Amplified Spontaneous Emission (ASE) source provides a wide emission bandwidth and improved spectral stability/purity for a given output power. The fiber ASE source is formed from a heavy metal oxide multicomponent glass selected from germanate, tellurite and bismuth oxides and doped with high concentrations, 0.5-15 wt. %, thulium oxides (Tm.sub.2O.sub.3) or 0.1-5 wt% holmium oxides (Ho.sub.2O.sub.3) or mixtures thereof. The high concentration of thulium dopants provide highly efficient pump absorption and high quantum efficiency. Co-doping of Tm and Ho can broaden the ASE spectrum.

  18. Characterization of gaseous pollutant and particulate matter emission rates from a commercial broiler operation part II: Correlated emission rates

    NASA Astrophysics Data System (ADS)

    Roumeliotis, Taylor S.; Dixon, Brad J.; Van Heyst, Bill J.

    2010-10-01

    Emission rates of ammonia, acid gases, inorganic aerosols, methane, and size fractionated particulate matter were measured from a commercial broiler facility. This paper discusses the statistically influential parameters on numerous pollutants' emission from a broiler chicken facility and generates emission correlations to fill data gaps and develop averaged emission factors. Live mass of the birds was commonly a significant variable to each pollutant's emission. Some variables significantly impacted the pollutants' emissions, such as litter moisture content, but were measured discretely and cannot be used for filling in data gaps. House parameter correlations were, therefore, developed using parameters measured at the facility, such as indoor temperature, relative humidity, and the live mass of the birds, and relied on the mutual behaviour of discretely measured explanatory parameters and continuously monitored confounding variables. The live mass and the difference in the indoor temperature and the house set-point temperature were the most significant variables in each pollutant's correlation. The correlations predicted each pollutants emission to within 20% (total mass basis) over most broiler production cycles. Their validation on independent datasets also successfully estimated the flocks' emissions to within 3%. Emission factors (EFs) were developed for methane, ammonia, and size fractionated particulate matter using measured data and correlated emissions to fill in data gaps. PM 10 (particulate matter ≤10 microns) EFs were estimated to be 4.6 and 5.9 g d -1 [Animal Unit, AU] -1 for five and six week production cycles, respectively. PM 2.5 (PM ≤ 2.5 microns) EFs were 0.8 and 1.4 g d -1 AU -1 for five and six week cycles, respectively. Ammonia and methane emission factors were estimated at 120.8 and 197.0 g d -1 AU -1, respectively for a five week production cycle.

  19. Particulate matter composition and emission rates from the disk incorporation of class B biosolids into soil

    NASA Astrophysics Data System (ADS)

    Paez-Rubio, Tania; Xin, Hua; Anderson, James; Peccia, Jordan

    Biosolids contain metal, synthetic organic compound, endotoxin, and pathogen concentrations that are greater than concentrations in the agricultural soils to which they are applied. Once applied, biosolids are incorporated into soils by disking and the aerosols produced during this process may pose an airborne toxicological and infectious health hazard to biosolids workers and nearby residents. Field studies at a Central Arizona biosolids land application site were conducted to characterize the physical, chemical, and biological content of the aerosols produced during biosolids disking and the content of bulk biosolids and soils from which the aerosols emanate. Arrayed samplers were used to estimate the vertical source aerosol concentration profile to enable plume height and associated source emission rate calculations. Source aerosol concentrations and calculated emission rates reveal that disking is a substantial source of biosolids-derived aerosols. The biosolids emission rate during disking ranged from 9.91 to 27.25 mg s -1 and was greater than previously measured emission rates produced during the spreading of dewatered biosolids or the spraying of liquid biosolids. Adding biosolids to dry soils increased the moisture content and reduced the total PM 10 emissions produced during disking by at least three times. The combination of bulk biosolids and aerosol measurements along with PM 10 concentrations provides a framework for estimating aerosol concentrations and emission rates by reconstruction. This framework serves to eliminate the difficulty and inherent limitations associated with monitoring low aerosol concentrations of toxic compounds and pathogens, and can promote an increased understanding of the associated biosolids aerosol health risks to workers and nearby residents.

  20. Acidic and total primary sulfates: development of emission factors for major stationary combustion sources

    SciTech Connect

    Goklany, I.M.; Hoffnagle, G.F.; Brackbill, E.A.

    1984-01-01

    ''Best estimates'' of emission factors for major sources of acidic and total primary sulfates are developed for use in the compilation of emission inventories for the eastern U.S. These may, in turn, be used for modeling of acidic or sulfate deposition. The factors are based upon a critical evaluation of the generic measurement methods used to quantify total and acidic primary sulfate emissions, and an exhaustive review and critique of individual papers and studies available in the open literature which present measurement data on primary sulfate emissions. It develops a qualitative rating scheme which specifies the level of confidence that should be attached to the emission factor determinations. The paper concludes that much of the existing data on primary sulfates from stationary combustion sources are, probably, significantly biased upward and, therefore, inappropriate for the derivation of emission factors. Therefore, existing estimates of primary sulfate emissions for these source categories are, probably, substanitally inflated. It also concludes that, for most source categories, very little confidence can be attached to the best estimates because of the paucity of data obtained from measurement techniques which are likely to be free of systematic bias. 68 references.

  1. Identification of surface NOx emission sources on a regional scale using OMI NO2

    NASA Astrophysics Data System (ADS)

    Zyrichidou, I.; Κoukouli, M. E.; Balis, D.; Markakis, K.; Poupkou, A.; Katragkou, E.; Kioutsioukis, I.; Melas, D.; Boersma, K. F.; van Roozendael, M.

    2015-01-01

    In this study, an inverse modeling technique is applied to obtain, at a regional scale, top-down emission estimates for nitrogen oxides utilizing tropospheric nitrogen dioxide (NO2) columns retrieved by the OMI/Aura instrument and estimated by the Comprehensive Air Quality Model with extensions (CAMx). The main idea, applied previously using models with coarse spatial resolution, is to combine the a priori information from the bottom up emission inventory used in an air quality simulation that covers the Balkan peninsula in a high resolution grid (0.1° × 0.1°) with the tropospheric NO2 quantities estimated for one complete year by CAMx and the tropospheric NO2 columns retrieved by satellite observations in order to identify missing emissions sources on a regional scale. The results have identified biases between the a priori and a posteriori emission inventories due to the missing emission sources or over-estimation of the spread and quantity of certain emission sources. In such a fine resolution grid we have also analyzed and considered the horizontal transport on the a posteriori NOx emissions. The deduced a posteriori NOx emissions, dominated by the fossil fuel emissions, were found to be1.11 ± 0.30 Tg N/y, compared to 0.87 ± 0.43 Tg N/y found in the a priori Balkan emission inventory. Soil emissions over the extended Greek domain, omitted in the a priori inventory, were estimated to account for almost 20% of the total emitted amount, while for the year 2009 the biomass burning NOx emission flux was also estimated and the average rate accounted for 0.5 × 10-6 Tg N/km2.

  2. UV emissions from low energy artificial light sources.

    PubMed

    Fenton, Leona; Moseley, Harry

    2014-01-01

    Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses.

  3. Large spontaneous emission rate enhancement in grating coupled hyperbolic metamaterials.

    PubMed

    Sreekanth, Kandammathe Valiyaveedu; Krishna, Koduru Hari; De Luca, Antonio; Strangi, Giuseppe

    2014-09-11

    Hyperbolic metamaterial (HMM), a sub-wavelength periodic artificial structure with hyperbolic dispersion, can enhance the spontaneous emission of quantum emitters. Here, we demonstrate the large spontaneous emission rate enhancement of an organic dye placed in a grating coupled hyperbolic metamaterial (GCHMM). A two-dimensional (2D) silver diffraction grating coupled with an Ag/Al2O3 HMM shows 18-fold spontaneous emission decay rate enhancement of dye molecules with respect to the same HMM without grating. The experimental results are compared with analytical models and numerical simulations, which confirm that the observed enhancement of GCHMM is due to the outcoupling of non-radiative plasmonic modes as well as strong plasmon-exciton coupling in HMM via diffracting grating.

  4. Emission rates of sulfur dioxide, trace gases and metals from Mount Erebus, Antarctica

    NASA Astrophysics Data System (ADS)

    Kyle, Philip R.; Meeker, Kimberley; Finnegan, David

    1990-11-01

    SO2 emission rates have been measured annually since 1983 at Mount Erebus, Antarctica by correlation spectrometer (COSPEC V). Following a 4 month period of sustained strombolian activity in late 1984, SO2 emissions declined from 230 Mg/day in 1983 to 25 Mg/day and then slowly increased from 16 Mg/day in 1985 to 51 Mg/day in 1987. Nine sets of filter packs containing particle and (Li-7)OH treated filters were collected in the plume in 1986 and analyzed by neutron activation. Using the COSPEC data and measured element/S ratios on the filters, emission rates have been determined for trace gases and metals. HCl and HF emissions in 1983 are inferred to be about 1200 and 500 Mg/day, respectively. Mt. Erebus has therefore been an important source of halogens to the Antarctic atmosphere and could be responsible for excess Cl found in central Antarctica snow.

  5. Source Attribution of Methane Emissions in Northeastern Colorado Using Ammonia to Methane Emission Ratios

    NASA Astrophysics Data System (ADS)

    Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; Perring, A. E.; Robinson, E. S.; Holloway, M.; Trainer, M.

    2015-12-01

    Due to recent advances in extraction technology, oil and natural gas extraction and processing in the Denver-Julesburg basin has increased substantially in the past decade. Northeastern Colorado is also home to over 250 concentrated animal feeding operations (CAFOs), capable of hosting over 2 million head of ruminant livestock (cattle and sheep). Because of methane's high Global Warming Potential, quantification and attribution of methane emissions from oil and gas development and agricultural activity are important for guiding greenhouse gas emission policy. However, due to the co-location of these different sources, top-down measurements of methane are often unable to attribute emissions to a specific source or sector. In this work, we evaluate the ammonia:methane emission ratio directly downwind of CAFOs using a mobile laboratory. Several CAFOs were chosen for periodic study over a 12-month period to identify diurnal and seasonal variation in the emission ratio as well as differences due to livestock type. Using this knowledge of the agricultural ammonia:methane emission ratio, aircraft measurements of ammonia and methane over oil and gas basins in the western US during the Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in March and April 2015 can be used for source attribution of methane emissions.

  6. Mapping methane emission sources over California based on airborne measurements

    NASA Astrophysics Data System (ADS)

    Karl, T.; Guha, A.; Peischl, J.; Misztal, P. K.; Jonsson, H.; Goldstein, A. H.; Ryerson, T. B.

    2011-12-01

    The California Global Warming Solutions Act of 2006 (AB 32) has created a need to accurately characterize the emission sources of various greenhouse gases (GHGs) and verify the existing state GHG inventory. Methane (CH4) is a major GHG with a global warming potential of 20 times that of CO2 and currently constitutes about 6% of the total statewide GHG emissions on a CO2 equivalent basis. Some of the major methane sources in the state are area sources where methane is biologically produced (e.g. dairies, landfills and waste treatment plants) making bottom-up estimation of emissions a complex process. Other potential sources include fugitive emissions from oil extraction processes and natural gas distribution network, emissions from which are not well-quantified. The lack of adequate field measurement data to verify the inventory and provide independently generated estimates further contributes to the overall uncertainty in the CH4 inventory. In order to gain a better perspective of spatial distribution of major CH4 sources in California, a real-time measurement instrument based on Cavity Ring Down Spectroscopy (CRDS) was installed in a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of airborne CH4 and CO2 measurements during eight unique flights which covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. The coincident VOC measurements, obtained through a high frequency proton transfer reaction mass spectrometer (PTRMS), aid in CH4 source identification. High mixing ratios of CH4 (> 2000 ppb) are observed consistently in all the flight transects above the Central Valley. These high levels of CH4 are accompanied by high levels of methanol which is an important

  7. Identification of emission sources of umbral flashes using phase congruency

    NASA Astrophysics Data System (ADS)

    Feng, Song; Yu, Lan; Yang, Yun-Fei; Ji, Kai-Fan

    2014-08-01

    The emission sources of umbral flashes (UFs) are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively novel model of shape perception, namely phase congruency (PC), uses phase information in the Fourier domain to identify the geometrical shape of the region of interest in different intensity levels, rather than intensity or gradient. Previous studies indicate that the model is suitable for identifying features with low contrast and low luminance. In the present paper, we applied the PC model to identify the emission sources of UFs and to locate their positions. For illustrating the high performance of our proposed method, two time sequences of Ca II H images derived from the Hinode/SOT on 2010 August 10 and 2013 August 20 were used. Furthermore, we also compared these results with the analysis results that are identified by the traditional/classical identification methods, including the gray-scale adjusted technique and the running difference technique. The result of our analysis demonstrates that our proposed method is more accurate and effective than the traditional identification methods when applied to identifying the emission sources of UFs and to locating their positions.

  8. 40 CFR 60.25 - Emission inventories, source surveillance, reports.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... previous progress reports. (6) Submission of copies of technical reports on all performance testing on... surveillance, reports. 60.25 Section 60.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... State Plans for Designated Facilities § 60.25 Emission inventories, source surveillance, reports....

  9. 40 CFR 60.25 - Emission inventories, source surveillance, reports.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... previous progress reports. (6) Submission of copies of technical reports on all performance testing on... surveillance, reports. 60.25 Section 60.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... State Plans for Designated Facilities § 60.25 Emission inventories, source surveillance, reports....

  10. 40 CFR 60.25 - Emission inventories, source surveillance, reports.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... previous progress reports. (6) Submission of copies of technical reports on all performance testing on... surveillance, reports. 60.25 Section 60.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... State Plans for Designated Facilities § 60.25 Emission inventories, source surveillance, reports....

  11. 40 CFR 60.25 - Emission inventories, source surveillance, reports.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... previous progress reports. (6) Submission of copies of technical reports on all performance testing on... surveillance, reports. 60.25 Section 60.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... State Plans for Designated Facilities § 60.25 Emission inventories, source surveillance, reports....

  12. 40 CFR 60.25 - Emission inventories, source surveillance, reports.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... previous progress reports. (6) Submission of copies of technical reports on all performance testing on... surveillance, reports. 60.25 Section 60.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... State Plans for Designated Facilities § 60.25 Emission inventories, source surveillance, reports....

  13. Sources of variation in waterfowl survival rates

    USGS Publications Warehouse

    Krementz, D.G.; Barker, R.J.; Nichols, J.D.

    1997-01-01

    Because of the need to manage hunted populations of waterfowl (Anatidae), biologists have studied many demographic traits of waterfowl by analyzing band recoveries. These analyses have produced the most extensive and best estimates of survival available for any group of birds. Using these data, we examined several factors that might explain variation among annual survival rates to explore large-scale patterns that might be useful in understanding waterfowl population dynamics. We found that geography, body mass, and tribe (i.e. phylogeny) were important in explaining variation in average waterfowl survival rates.

  14. Acidifier application rate impacts on ammonia emissions from US roaster chicken houses

    NASA Astrophysics Data System (ADS)

    Shah, Sanjay B.; Grimes, Jesse L.; Oviedo-Rondón, Edgar O.; Westerman, Philip W.

    2014-08-01

    Due to its potential environmental and public health impacts, emissions of ammonia (NH3) as well as several other gases from US livestock farms may be regulated. Broiler houses are important sources of NH3 emissions. However, there are no emissions data from roaster (8-12 wk old broilers, ˜4 kg ea.) houses. Producers treat the litter in broiler houses with acidifiers, such as sodium bisulfate (SBS, NaHSO4) to reduce ammonia production and protect bird health. However, there is very little data on the effect of acidifiers, particularly at high application rates on ammonia emissions. The impact of different SBS application rates [High (0.95-1.46 kg m-2, whole house), Medium (0.73 kg m-2, whole house), Low (0.37-0.49 kg m-2, whole house), and Control (0.37-0.49 kg m-2, brood chamber)] on ammonia emissions was evaluated in commercial roaster houses over 22 months spanning eight flocks. Ammonia emission from each fan was measured with an acid scrubber that operated only when the fan operated. Emissions were calculated using >95% measured data with the rest being estimated using robust methods. Exhaust ammonia-N concentrations were inversely correlated with the SBS application rates. Emission rates on animal unit (AU, where 1 AU = 500 kg live-mass) basis (ER, g d-1 AU-1) were reduced by 27, 13, and 5%, respectively, in the High, Medium, and Low treatments vs. the Control treatment (mean: 100 g d-1 AU-1, range: 86-114 g d-1 AU-1). Emission rates for the Control treatment measured in this study on roasters were mostly higher than ERs in the literature. Differences in ERs are not only due to diet, environmental and management conditions, but also due to measurement methods.

  15. Characterization of publication rotogravure press emission rates and compositions.

    PubMed

    Wadden, R A; Suero, M; Conroy, L M; Franke, J E; Scheff, P A

    2001-04-01

    Emission compositions and rates were determined during production for a publication rotogravure press room at a large rotogravure printing company. The press room housed a single 4-color, 8-print-stand press, with an 84" paper web. Average press speed was 1800 feet per minute. Data were collected over a 2-day period and included measurements of ventilation, room area concentrations, duct exhaust compositions, amount and composition of inks used, and worker exposures. These data were used with mass balance models that were appropriate for the workspace. Toluene comprised more than 90 percent of the inks and solvents and accounted for more than 90 percent of the press emissions. Average toluene emissions during press operation and press off conditions were 222 kg/hr and 8-38 kg/hr, respectively. The uncontrolled toluene emission on the basis of printed paper throughput was 3 g/m2. Of the total toluene released, 90 percent was captured by the local exhaust ventilation. The measured control efficiency was much lower than the average efficiency of 97 percent for the month of the test reported by the plant. A mass balance model evaluation demonstrated that only the lower efficiency was consistent with measured room concentrations. Using the measured emission rates and actual monthly press on and press off conditions, the difference in efficiency for the plant (10 rotogravure presses) extrapolates to the additional release to the workspace and ambient environment of over 700 tons/yr of toluene.

  16. Airborne reduced nitrogen: ammonia emissions from agriculture and other sources.

    PubMed

    Anderson, Natalie; Strader, Ross; Davidson, Cliff

    2003-06-01

    Ammonia is a basic gas and one of the most abundant nitrogen-containing compounds in the atmosphere. When emitted, ammonia reacts with oxides of nitrogen and sulfur to form particles, typically in the fine particle size range. Roughly half of the PM(2.5) mass in eastern United States is ammonium sulfate, according to the US EPA. Results from recent studies of PM(2.5) show that these fine particles are typically deposited deep in the lungs and may lead to increased morbidity and/or mortality. Also, these particles are in the size range that will degrade visibility. Ammonia emission inventories are usually constructed by multiplying an activity level by an experimentally determined emission factor for each source category. Typical sources of ammonia include livestock, fertilizer, soils, forest fires and slash burning, industry, vehicles, the oceans, humans, pets, wild animals, and waste disposal and recycling activities. Livestock is the largest source category in the United States, with waste from livestock responsible for about 3x10(9) kg of ammonia in 1995. Volatilization of ammonia from livestock waste is dependent on many parameters, and thus emission factors are difficult to predict. Despite a seasonal variation in these values, the emission factors for general livestock categories are usually annually averaged in current inventories. Activity levels for livestock are from the USDA Census of Agriculture, which does not give information about animal raising practices such as housing types and grazing times, waste handling systems, and approximate animal slurry spreading times or methods. Ammonia emissions in the United States in 1995 from sources other than livestock are much lower; for example, annual emissions are roughly 8x10(8) kg from fertilizer, 7x10(7) kg from industry, 5x10(7) kg from vehicles and 1x10(8) kg from humans. There is considerable uncertainty in the emissions from soil and vegetation, although this category may also be significant

  17. Source characteristics of Jovian narrow-band kilometric radio emissions

    NASA Astrophysics Data System (ADS)

    Reiner, M. J.; Fainberg, J.; Stone, R. G.; Kaiser, M. L.; Desch, M. D.; Manning, R.; Zarka, P.; Pedersen, B.-M.

    1993-07-01

    New observations of Jovian narrow-band kilometric (nKOM) radio emissions were made by the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in early February 1992. These observations have demonstrated the unique capability of the URAP instrument for determining both the direction and polarization of nKOM radio sources. An important result is the discovery that nKOM radio emission originates from a number of distinct sources located at different Jovian longitudes and at the inner and outermost regions of the Io plasma torus. These sources have been tracked for several Jovian rotations, yielding their corotational lags, their spatial and temporal evolution, and their radiation characteristics at both low latitudes far from Jupiter and at high latitudes near the planet. Both right-hand and left-hand circularly polarized nKOM sources were observed. The polarizations observed for sources in the outermost regions of the torus seem to favor extraordinary mode emission.

  18. ALMA Band 8 Continuum Emission from Orion Source I

    NASA Astrophysics Data System (ADS)

    Hirota, Tomoya; Machida, Masahiro N.; Matsushita, Yuko; Motogi, Kazuhito; Matsumoto, Naoko; Kim, Mi Kyoung; Burns, Ross A.; Honma, Mareki

    2016-12-01

    We have measured continuum flux densities of a high-mass protostar candidate, a radio source I in the Orion KL region (Orion Source I) using the Atacama Large Millimeter/Submillimeter Array (ALMA) at band 8 with an angular resolution of 0.″1. The continuum emission at 430, 460, and 490 GHz associated with Source I shows an elongated structure along the northwest-southeast direction perpendicular to the so-called low-velocity bipolar outflow. The deconvolved size of the continuum source, 90 au × 20 au, is consistent with those reported previously at other millimeter/submillimeter wavelengths. The flux density can be well fitted to the optically thick blackbody spectral energy distribution, and the brightness temperature is evaluated to be 700-800 K. It is much lower than that in the case of proton-electron or H- free-free radiations. Our data are consistent with the latest ALMA results by Plambeck & Wright, in which the continuum emission was proposed to arise from the edge-on circumstellar disk via thermal dust emission, unless the continuum source consists of an unresolved structure with a smaller beam filling factor.

  19. Footprint methods to separate N2O emission rates from adjacent paddock areas

    NASA Astrophysics Data System (ADS)

    Mukherjee, Sandipan; McMillan, Andrew M. S.; Sturman, Andrew P.; Harvey, Mike J.; Laubach, Johannes

    2015-03-01

    Using micrometeorological techniques to measure greenhouse gas emissions from differently treated adjacent plots is a promising avenue to verify the effect of mitigation strategies at the field scale. In pursuing such an approach, it is crucial to accurately characterize the source area of the fluxes measured at each sampling point. Hence, a comprehensive footprint analysis method is required so that emission rates can be obtained for a specific field within a biochemically heterogeneous area. In this study, a footprint analysis method is developed to estimate the emission for an experiment where the flux of N2O is measured from several control and treated plots. The emission rate of an individual plot is estimated using an inverse footprint fraction approach where the footprint fractions are obtained from an analytical footprint model. A numerical solution for obtaining the background flux for such a multiplot measurement system is also provided. Results of the footprint analysis method are assessed, first, by comparing footprint fractions obtained from both an analytical footprint model and a "forward" simulation of a backward Lagrangian stochastic (bLs) model; and second, by comparing the emission rates of a control plot obtained from the footprint analysis method and from the "backward" simulation of the bLs model. It is found that the analytical footprint fractions compare well with the values obtained from the bLs model (correlation coefficient of 0.58 and 0.66 within p value <0.001). An average of 4.3 % of the measured fluxes is found to be contributed by sources outside the measured area and, excluding this outside area contribution to the measured flux, footprint corrected emission rates within the defined domain are found to increase by 2.1 to 5.8 % of the measured flux. Also, the proposed method of emission rate estimation is found to work well under a wide range of atmospheric stability.

  20. Suppression of emission rates improves sonar performance by flying bats.

    PubMed

    Adams, Amanda M; Davis, Kaylee; Smotherman, Michael

    2017-01-31

    Echolocating bats face the challenge of actively sensing their environment through their own emissions, while also hearing calls and echoes of nearby conspecifics. How bats mitigate interference is a long-standing question that has both ecological and technological implications, as biosonar systems continue to outperform man-made sonar systems in noisy, cluttered environments. We recently showed that perched bats decreased calling rates in groups, displaying a behavioral strategy resembling the back-off algorithms used in artificial communication networks to optimize information throughput at the group level. We tested whether free-tailed bats (Tadarida brasiliensis) would employ such a coordinated strategy while performing challenging flight maneuvers, and report here that bats navigating obstacles lowered emission rates when hearing artificial playback of another bat's calls. We measured the impact of acoustic interference on navigation performance and show that the calculated reductions in interference rates are sufficient to reduce interference and improve obstacle avoidance. When bats flew in pairs, each bat responded to the presence of the other as an obstacle by increasing emissions, but hearing the sonar emissions of the nearby bat partially suppressed this response. This behavior supports social cohesion by providing a key mechanism for minimizing mutual interference.

  1. Suppression of emission rates improves sonar performance by flying bats

    PubMed Central

    Adams, Amanda M.; Davis, Kaylee; Smotherman, Michael

    2017-01-01

    Echolocating bats face the challenge of actively sensing their environment through their own emissions, while also hearing calls and echoes of nearby conspecifics. How bats mitigate interference is a long-standing question that has both ecological and technological implications, as biosonar systems continue to outperform man-made sonar systems in noisy, cluttered environments. We recently showed that perched bats decreased calling rates in groups, displaying a behavioral strategy resembling the back-off algorithms used in artificial communication networks to optimize information throughput at the group level. We tested whether free-tailed bats (Tadarida brasiliensis) would employ such a coordinated strategy while performing challenging flight maneuvers, and report here that bats navigating obstacles lowered emission rates when hearing artificial playback of another bat’s calls. We measured the impact of acoustic interference on navigation performance and show that the calculated reductions in interference rates are sufficient to reduce interference and improve obstacle avoidance. When bats flew in pairs, each bat responded to the presence of the other as an obstacle by increasing emissions, but hearing the sonar emissions of the nearby bat partially suppressed this response. This behavior supports social cohesion by providing a key mechanism for minimizing mutual interference. PMID:28139707

  2. EPA's mobile monitoring of source emissions and near-source impact

    EPA Science Inventory

    Real-time ambient monitoring onboard a moving vehicle is a unique data collection approach applied to characterize large-area sources, such as major roadways, and detect fugitive emissions from distributed sources, such as leaking oil wells. EPA's Office of Research and Developme...

  3. Determination of VOC emission rates and compositions for offset printing.

    PubMed

    Wadden, R A; Scheff, P A; Franke, J E; Conroy, L M; Keil, C B

    1995-07-01

    The release rates of volatile organic compounds (VOC) as fugitive emissions from offset printing are difficult to quantify, and the compositions are usually not known. Tests were conducted at three offset printing shops that varied in size and by process. In each case, the building shell served as the test "enclosure," and air flow and concentration measurements were made at each air entry and exit point. Emission rates and VOC composition were determined during production for (1) a small shop containing three sheetfed presses and two spirit duplicators (36,700 sheets, 47,240 envelopes and letterheads), (2) a medium-size industrial in-house shop with two webfed and three sheetfed presses, and one spirit duplicator (315,130 total sheets), and (3) one print room of a large commercial concern containing three webfed, heatset operations (1.16 x 10(6) ft) served by catalytic air pollution control devices. Each test consisted of 12 one-hour periods over two days. Air samples were collected simultaneously during each period at 7-14 specified locations within each space. The samples were analyzed by gas chromatography (GC) for total VOC and for 13-19 individual organics. Samples of solvents used at each shop were also analyzed by GC. Average VOC emission rates were 4.7-6.1 kg/day for the small sheetfed printing shop, 0.4-0.9 kg/day for the industrial shop, and 79-82 kg/day for the commercial print room. Emission compositions were similar and included benzene, toluene, xylenes, ethylbenzene, and hexane. Comparison of the emission rates with mass balance estimates based on solvent usage and composition were quite consistent.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Acoustic emission strand burning technique for motor burning rate prediction

    NASA Technical Reports Server (NTRS)

    Christensen, W. N.

    1978-01-01

    An acoustic emission (AE) method is being used to measure the burning rate of solid propellant strands. This method has a precision of 0.5% and excellent burning rate correlation with both subscale and large rocket motors. The AE procedure burns the sample under water and measures the burning rate from the acoustic output. The acoustic signal provides a continuous readout during testing, which allows complete data analysis rather than the start-stop clockwires used by the conventional method. The AE method helps eliminate such problems as inhibiting the sample, pressure increase and temperature rise, during testing.

  5. EPA`s emissions models for general nonroad sources

    SciTech Connect

    Fieber, J.; Rosenbaum, A.; Vranka, R.; Kleinhesselink, D.

    1996-12-31

    Under the sponsorship of the US EPA`s Office of Mobile Sources, SAI has developed a computer model for nonroad mobile sources. Although data and methodologies continue to be revisited, the alpha version of the model has been completed and is currently under review at EPA. The model contains modules for estimating equipment populations, activity, emission factors, and total emissions. It adjusts these estimates to predict total emissions for the calendar year and at a level of detail specified by the user (e.g., average annual estimates at a national level, hourly estimates for a specific county). The EPA`s nonroad model provides estimates for the following general classes of nonroad equipment: General Nonroad Sources: (1) Lawn and garden equipment; (2) Airport service equipment; (3) Recreational; (4) Light Commercial; (5) Industrial; (6) Construction; (7) Agricultural; and (8) Logging. Special Nonroad Sources: (1) Locomotives; (2) Aircraft; and (3) Marine Vessels. With the exception of locomotives, aircraft, and marine vessels, the methodologies used within the model are quite similar for all these source groupings. Information for specific equipment types (e.g., 15-25 horsepower, gasoline 2-stroke engine commercial turf equipment) will also be provided if the user requests this level of detail. Written in FORTRAN and designed for personal computers (though it can be ported to workstations), this new emissions tool includes an interface to improve its ease of use and flexibility. We present here some of the features of the model and provide an overview of the internal methods used for the equipment groups listed under general nonroad sources.

  6. Indoor aldehydes concentration and emission rate of formaldehyde in libraries and private reading rooms

    NASA Astrophysics Data System (ADS)

    Kim, Jeonghoon; Kim, Seojin; Lee, Kiyoung; Yoon, Dongwon; Lee, Jiryang; Ju, DaeYoung

    2013-06-01

    Aldehydes are of particularly interest due to their potential adverse impact on human health. Formaldehyde is one of the most abundant indoor pollutants. To improve indoor air quality, identifying and removing the major emission sources of formaldehyde would be desirable. The purposes of this study were to determine aldehyde concentrations in libraries and reading rooms and to identify emission sources of formaldehyde in private reading rooms. Indoor aldehyde concentrations were quantified at 66 facilities, including public libraries, children's libraries, public reading rooms, and private reading rooms, in the Seoul metropolitan area. Emission fluxes of formaldehyde from the surfaces of desks, chairs, floors, walls, and ceilings in 19 private reading rooms were measured using a passive emission colorimetric sensor. Indoor aldehyde (formaldehyde, acetaldehyde, propioaldehyde, benzaldehyde, and hexaldehyde) levels were significantly higher than outdoor levels. Indoor formaldehyde geometric mean concentrations in private reading rooms (119.3 μg m-3) were significantly higher than in public libraries (29.2 μg m-3), children's libraries (29.3 μg m-3), and public reading rooms (40.8 μg m-3). Indoor formaldehyde levels were associated with relative humidity. In private reading rooms, the emission rates from desks (255.5 ± 214.8 μg h-1) and walls (231.7 ± 192.3 μg h-1) were significantly higher than that from chairs (79.6 ± 88.5 μg h-1). Desks (31%) and walls (29%) were the major emission sources of formaldehyde in 14 facilities in which measurements exceeded the indoor standard of 100 μg m-3. The age of interior materials was a significant factor for indoor formaldehyde emission flux. Controlling the emission rates of desks and walls is recommended to improve formaldehyde concentrations in private reading rooms.

  7. Study Pinpoints Sources of Polluting Vehicle Emissions (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    aftertreatment, high-molecular-weight fuel components and unburned lubricant were emitted at higher rates than in vehicles in good repair, with functioning emissions systems. Light-duty gasoline, medium-duty diesel, and heavy-duty natural gas vehicles produced more particles with fresh oil than with aged oil. The opposite trend was observed in light- and medium-duty high PM emitters. This effect was not readily apparent with heavy-duty diesel vehicles, perhaps because the lubricant represented a much smaller fraction of the total PM in those trucks.

  8. HVAC SYSTEMS AS EMISSION SOURCES AFFECTING INDOOR AIR QUALITY: A CRITICAL REVIEW

    EPA Science Inventory

    The study evaluates heating, ventilating, and air-conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). Various literature sources and methods for characterizing HVAC emission sources are reviewed. Available methods include in situ test...

  9. Modeling Atmospheric Emissions and Calculating Mortality Rates Associated with High Volume Hydraulic Fracturing Transportation

    NASA Astrophysics Data System (ADS)

    Mathews, Alyssa

    Emissions from the combustion of fossil fuels are a growing pollution concern throughout the global community, as they have been linked to numerous health issues. The freight transportation sector is a large source of these emissions and is expected to continue growing as globalization persists. Within the US, the expanding development of the natural gas industry is helping to support many industries and leading to increased transportation. The process of High Volume Hydraulic Fracturing (HVHF) is one of the newer advanced extraction techniques that is increasing natural gas and oil reserves dramatically within the US, however the technique is very resource intensive. HVHF requires large volumes of water and sand per well, which is primarily transported by trucks in rural areas. Trucks are also used to transport waste away from HVHF well sites. This study focused on the emissions generated from the transportation of HVHF materials to remote well sites, dispersion, and subsequent health impacts. The Geospatial Intermodal Freight Transport (GIFT) model was used in this analysis within ArcGIS to identify roadways with high volume traffic and emissions. High traffic road segments were used as emissions sources to determine the atmospheric dispersion of particulate matter using AERMOD, an EPA model that calculates geographic dispersion and concentrations of pollutants. Output from AERMOD was overlaid with census data to determine which communities may be impacted by increased emissions from HVHF transport. The anticipated number of mortalities within the impacted communities was calculated, and mortality rates from these additional emissions were computed to be 1 in 10 million people for a simulated truck fleet meeting stricter 2007 emission standards, representing a best case scenario. Mortality rates due to increased truck emissions from average, in-use vehicles, which represent a mixed age truck fleet, are expected to be higher (1 death per 341,000 people annually).

  10. Isoprene and terpenoid emissions from Abies alba: Identification and emission rates under ambient conditions

    NASA Astrophysics Data System (ADS)

    Pokorska, Olga; Dewulf, Jo; Amelynck, Crist; Schoon, Niels; Šimpraga, Maja; Steppe, Kathy; Van Langenhove, Herman

    2012-11-01

    In this study, biogenic volatile organic compound (BVOC) emissions from Abies alba were studied under ambient conditions in Flanders (Belgium). Emission patterns and rates were investigated from April till November 2010 by using the dynamic branch enclosure technique. The present work revealed that A. alba is an isoprene emitter, with isoprene accounting for 86-93% of total BVOC emissions, except during budburst (67%) in May. The emission spectrum of A. alba consisted of 27 compounds. Next to isoprene, the main emitted compounds were α-pinene, β-pinene, camphene and limonene. BVOC emissions showed a peak in June after development of the young needles, followed by a constant emission during summer months and September and a decrease in October. In all the samples isoprene was the most abundant compound with standardized emission rates between 27 μg g(dw)-1 h-1 in June and 4.6 μg g(dw)-1 h-1 in October, while the total standardized terpenoid emission rates ranged from 2.85 μg g(dw)-1 h-1 in June to 0.26 μg g(dw)-1 h-1 in October. The obtained average β coefficients according to the temperature dependent algorithm of Guenther et al. (1993) during April-June, July, August and September-October were as follows: for terpenoids 0.12 ± 0.03, 0.11 ± 0.05, 0.12 ± 0.04, 0.24 ± 0.01 K-1 and sesquiterpenes (SQTs) 0.09 ± 0.02, 0.11 ± 0.01, 0.10 ± 0.05, 0 K-1, respectively. Overall, isoprene detected in this study was never quantified in previous studies on A. alba and this finding could have a significant impact on the regional BVOCs budget. Therefore, the result of this study is very important for modeling and local air quality.

  11. A global gas flaring black carbon emission rate dataset from 1994 to 2012.

    PubMed

    Huang, Kan; Fu, Joshua S

    2016-11-22

    Global flaring of associated petroleum gas is a potential emission source of particulate matters (PM) and could be notable in some specific regions that are in urgent need of mitigation. PM emitted from gas flaring is mainly in the form of black carbon (BC), which is a strong short-lived climate forcer. However, BC from gas flaring has been neglected in most global/regional emission inventories and is rarely considered in climate modeling. Here we present a global gas flaring BC emission rate dataset for the period 1994-2012 in a machine-readable format. We develop a region-dependent gas flaring BC emission factor database based on the chemical compositions of associated petroleum gas at various oil fields. Gas flaring BC emission rates are estimated using this emission factor database and flaring volumes retrieved from satellite imagery. Evaluation using a chemical transport model suggests that consideration of gas flaring emissions can improve model performance. This dataset will benefit and inform a broad range of research topics, e.g., carbon budget, air quality/climate modeling, and environmental/human exposure.

  12. A global gas flaring black carbon emission rate dataset from 1994 to 2012

    PubMed Central

    Huang, Kan; Fu, Joshua S.

    2016-01-01

    Global flaring of associated petroleum gas is a potential emission source of particulate matters (PM) and could be notable in some specific regions that are in urgent need of mitigation. PM emitted from gas flaring is mainly in the form of black carbon (BC), which is a strong short-lived climate forcer. However, BC from gas flaring has been neglected in most global/regional emission inventories and is rarely considered in climate modeling. Here we present a global gas flaring BC emission rate dataset for the period 1994–2012 in a machine-readable format. We develop a region-dependent gas flaring BC emission factor database based on the chemical compositions of associated petroleum gas at various oil fields. Gas flaring BC emission rates are estimated using this emission factor database and flaring volumes retrieved from satellite imagery. Evaluation using a chemical transport model suggests that consideration of gas flaring emissions can improve model performance. This dataset will benefit and inform a broad range of research topics, e.g., carbon budget, air quality/climate modeling, and environmental/human exposure. PMID:27874852

  13. A global gas flaring black carbon emission rate dataset from 1994 to 2012

    NASA Astrophysics Data System (ADS)

    Huang, Kan; Fu, Joshua S.

    2016-11-01

    Global flaring of associated petroleum gas is a potential emission source of particulate matters (PM) and could be notable in some specific regions that are in urgent need of mitigation. PM emitted from gas flaring is mainly in the form of black carbon (BC), which is a strong short-lived climate forcer. However, BC from gas flaring has been neglected in most global/regional emission inventories and is rarely considered in climate modeling. Here we present a global gas flaring BC emission rate dataset for the period 1994-2012 in a machine-readable format. We develop a region-dependent gas flaring BC emission factor database based on the chemical compositions of associated petroleum gas at various oil fields. Gas flaring BC emission rates are estimated using this emission factor database and flaring volumes retrieved from satellite imagery. Evaluation using a chemical transport model suggests that consideration of gas flaring emissions can improve model performance. This dataset will benefit and inform a broad range of research topics, e.g., carbon budget, air quality/climate modeling, and environmental/human exposure.

  14. Polychlorinated Biphenyl Sources, Emissions, and Environmental Levels in School Buildings

    EPA Science Inventory

    Building materials and components containing polychlorinated biphenyls (PCBs) were used in some U.S. school buildings until the late 1970s and may be present today. PCB emission rates from caulk and fluorescent light ballasts were measured in laboratory chambers. PCB concentrat...

  15. Accurate Simulation of Acoustic Emission Sources in Composite Plates

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Gorman, M. R.

    1994-01-01

    Acoustic emission (AE) signals propagate as the extensional and flexural plate modes in thin composite plates and plate-like geometries such as shells, pipes, and tubes. The relative amplitude of the two modes depends on the directionality of the source motion. For source motions with large out-of-plane components such as delaminations or particle impact, the flexural or bending plate mode dominates the AE signal with only a small extensional mode detected. A signal from such a source is well simulated with the standard pencil lead break (Hsu-Neilsen source) on the surface of the plate. For other sources such as matrix cracking or fiber breakage in which the source motion is primarily in-plane, the resulting AE signal has a large extensional mode component with little or no flexural mode observed. Signals from these type sources can also be simulated with pencil lead breaks. However, the lead must be fractured on the edge of the plate to generate an in-plane source motion rather than on the surface of the plate. In many applications such as testing of pressure vessels and piping or aircraft structures, a free edge is either not available or not in a desired location for simulation of in-plane type sources. In this research, a method was developed which allows the simulation of AE signals with a predominant extensional mode component in composite plates requiring access to only the surface of the plate.

  16. Air quality assessment and control of emission rates.

    PubMed

    Skiba, Yuri N; Parra-Guevara, David; Belitskaya, Davydova Valentina

    2005-12-01

    Mathematical methods based on the adjoint model approach are given for the air-pollution estimation and control in an urban region. A simple advection-diffusion-reaction model and its adjoint are used to illustrate the application of the methods. Dual pollution concentration estimates in ecologically important zones are derived and used to develop two non-optimal strategies and one optimal strategy for controlling the emission rates of enterprises. A linear convex combination of these strategies represents a new sufficient strategy. A method for detecting the enterprises, which violate the emission rates prescribed by a control, is given. A method for determining an optimal position for a new enterprise in the region is also described.

  17. The infrared emission bands. III. Southern IRAS sources.

    PubMed

    Cohen, M; Tielens, A G; Bregman, J; Witteborn, F C; Rank, D M; Allamandola, L J; Wooden, D H; de Muizon, M

    1989-06-01

    We present airborne 5-8 micrometers spectra of southern IRAS sources which reveal strong polycyclic aromatic hydrocarbon (PAH) emission features. The good correlation between the bands, in particular the dominant 6.2 and "7.7" micrometers features, strongly imply a common carrier, reinforcing the PAH hypothesis. However, small but detectable spectral variations exist. Planetaries have a distinctly different ratio of I(6.2)/I(7.7) than other nebulae, accompanied by a redward shift in the actual wavelength of the "7.7" micrometers peak. Further, we have detected a new feature, previously predicted from laboratory spectra of PAH molecules, at 5.2 micrometers in many of these sources. Spectra of two rare [WC 10] planetary nebular nuclei indicate a very prominent plateau of emission, linking the 6.2 and 7.7 micrometers bands. Several of our sources show definite evidence for emission structure between 14 and 23 micrometers in their IRAS Low-Resolution Spectral Atlas spectra: we attribute this structure to PAH bands. too. We have defined the "generic" spectrum of emission bands relating the mean intensities of each band to that of the strongest, near 7.7 micrometers. We have added three more planetary or protoplanetary nebulae to our correlation between 7.7 micrometers band intensity and nebular gas phase C/O ratio, namely NGC 6302, HR 4049, and the highly carbon-rich [WC 10] nucleus, CPD--56 degrees 8032. For the latter we have determined a ratio for C/O of approximately 4.8 from IUE observations. The good correlation between the intensity ratio of the "7.7" micrometers feature relative to the far-infrared dust continuum and nebular C/O also supports a carbonaceous carrier for these emission features.

  18. Measurement of roadway PM10 emission rates using tracer techniques. Final technical report

    SciTech Connect

    Kantamaneni, R.; Claiborn, C.

    1996-03-01

    In the work, stationary and mobile point source tracer release techniques were used to determine PM10 emission rates from 4-lane commercia/residential paved roads under sanded and unsanded conditions, and from unpaved roads relative to site specific vehicular and ambient parameters. Measured stress (4+ lanes; > or = to 10,000 vehicles/day) emission factors for unsanded and sanded roads were respectively 40% and 10% lower than the EPA approved reference value. Preliminary results indicate a consistent relationship between PM10 and relative humidity under unsanded conditions. Evidence suggests that street sweeping has a negligible effect on PM10 emission reduction. Considerable uncertainties were observed with the empirical emission factor equation.

  19. Volatile organic compound emission rates from mixed deciduous and coniferous forests in Northern Wisconsin, USA

    NASA Astrophysics Data System (ADS)

    Isebrands, J. G.; Guenther, A. B.; Harley, P.; Helmig, D.; Klinger, L.; Vierling, L.; Zimmerman, P.; Geron, C.

    Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regions of the world to understand regional and global impacts and to implement possible mitigation strategies. The mixed deciduous and coniferous forests of northern Wisconsin, USA, were predicted to have significant VOC emission rates because they are comprised of many genera (i.e. Picea, Populus, Quercus, Salix) known to be high VOC emitters. In July 1993, a study was conducted on the Chequamegon National Forest near Rhinelander, WI, to identify and quantify VOC emitted from major trees, shrubs, and understory herbs in the mixed northern forests of this region. Emission rates were measured at various scales - at the leaf level with cuvettes, the branch level with branch enclosures, the canopy level with a tower based system, and the landscape level with a tethered balloon air sampling system. Area-average emission rates were estimated by scaling, using biomass densities and species composition along transects representative of the study site. Isoprene (C 5H 8) was the primary VOC emitted, although significant quantities of monoterpenes (C 10H 16) were also emitted. The highest emission rates of isoprene (at 30°C and photosynthetically active radiation of 1000 μmol m -2 s -1) were from northern red oak ( Quercus rubra, >110 μg(C) g -1 h -1); aspen ( Populus tremuloides, >77); willow ( Salix spp., >54); and black spruce ( Picea mariana, >10). Emission rates of hybrid poplar clones ranged from 40 to 90 μg(C) g -1 h -1 at 25°C; those of Picea provenances were generally <10, and emission rates of a hybrid between North American and European spruces were intermediate to parental rates. More than 30 species of plants were surveyed from the sites, including several from previously unstudied

  20. Global High-Resolution Emission Inventories from Combustion Sources

    NASA Astrophysics Data System (ADS)

    Tao, S.; Huang, Y.; Chen, H.; Shen, H.

    2014-12-01

    A series efforts have been made to reduce uncertainty of emission inventories from combustion sources. The inventories developed are highly resolved spatially (0.1 degree), temporally (monthly or daily), and sectorically (over 60 combustion sources). Sub-national, instead of national fuel data are used to reduce spatial bias due to uneven distribution of per person energy consumption within large countries. Space-for-time substitution method was developed to model the dependence of residential energy consumptions on a series of meteorological and socioeconomic conditions. The regression models were used to project temporal variation of energy consumption, subsequently emissions of greenhouse gases and air pollutants. The models can also be used to downscale spatial distribution of residential emissions. By using this approach, global emission inventories of black carbon, polycyclic aromatic hydrocarbons, mercury, TSP, PM10, and PM2.5 have been established. The inventories were used to potential health impact assessment, atmospheric transport and long-range transport modeling, as well as exposure and health impact modeling.

  1. Field measurement of greenhouse gas emission rates and development of emission factors for wastewater treatment. Final report, September 1994-March 1997

    SciTech Connect

    Eklund, B.; LaCosse, J.

    1997-09-01

    The report gives results of field testing to develop more reliable greenhouse gas (GHG) emission estimates for Wastewater treatment (WWT) lagoons. Field tests of emissions were conducted for WWT lagoons that use anaerobic processes to treat large volumes of wastewater with large biological oxygen demand (BOD) loadings. Air emissions and wastewater were measured at anaerobic lagoons at three meat processing plants and two publicly owned treatment works. The overall emission rates of CH4, carbon dioxide, carbon monoxide, nitrous oxide, ammonia (NH3), and chlorofluorocarbons were measured from each source using an open-path monitoring approach. The emitted compounds were identified and quantified by Fourier-Transform Infrared spectroscopy. Emission factors were developed for CH4 and NH3 as a function of the plant production rate, wastewater parameters (e.g., influent BOD and chemical oxygen demand (COD) loadings), and WWT system performance (e.g., BOD and COD removal rates).

  2. Mitigation strategies for methane emissions from agricultural sources

    SciTech Connect

    Duxbury, J.M.

    1993-12-31

    Anthropogenic emissions of CH{sub 4} account for 70% of total global emissions of this greenhouse gas. Current anthropogenic emissions of CH{sub 4} in the US are estimated to be between 24-30 Tg CH{sub 4} or 7-9% of the global anthropogenic total. By comparison the US is responsible for 27% of anthropogenic emissions of CO{sub 2} from fossil fuel use. Table 1 shows that the major anthropogenic sources of CH{sub 4} in the US are landfills (37%), domestic livestock and livestock waste (31%) and the coal mining/natural gas/petroleum industries (28%). On a global basis it is estimated that US landfills contribute 30% to the global landfill total, whereas livestock (including waste) and the coal mining/natural gas/petroleum industries each contribute about 8% to their respective global totals. The US is an insignificant contributor (< 1%) to global emissions of CH{sub 4} from rice paddies.

  3. Carbonyl emissions from vehicular exhausts sources in Hong Kong.

    PubMed

    Ho, Steven Sai Hang; Ho, Kin Fai; Lee, Shun Cheng; Cheng, Yan; Yu, Jian Zhen; Lam, Ka Man; Feng, Natale Sin Yau; Huang, Yu

    2012-02-01

    Vehicular emission (VE) is one of the important anthropogenic sources for airborne carbonyls in urban area. Six types of VE-dominated samples were collected at representative locations in Hong Kong where polluted by a particular fueled type of vehicles, including (i) a gas refilling taxis station (liquefied petroleum gas [LPG] emission); (ii) a light-duty passenger car park (gasoline emission); (iii) a minibus station (diesel emission); (iv) a single-deck-bus depot (diesel emission); (v) a double-deck-bus depot (diesel emission); and (vi) a whole-food market entrance for light- and heavy-duty vehicles (diesel emission). A total of 15 carbonyls in the samples were quantified. Formaldehyde was the most abundant carbonyl among the VE-dominated samples, and its contribution to the total quantified amount on a molar basis ranged from 54.8% to 60.8%. Acetaldehyde and acetone were the next two abundant carbonyls. The carbonyls were quantified at three roadside locations in Hong Kong. The highest concentrations of formaldehyde and acetaldehyde, 22.7 +/- 8.4 and 6.0 +/- 2.8 microg/m3, respectively, were determined in the samples collected at a main transportation gate for goods between Hong Kong and Mainland China. The total quantified carbonyl concentration, 37.9 +/- 9.3 microg/m3, was the highest at an entrance of a cross-harbor tunnel in downtown area. The theoretical carbonyls compositions of the three roadside locations were estimated according to the VE-dominated sample profiles and the statistics on vehicle numbers and types during the sampling period. The measured compositions of formaldehyde were much higher than the theoretical compositions in summer, demonstrating that photochemical reactions significantly contributed to the formaldehyde production in the roadsides.

  4. Plasma emission spectroscopy for operating and developing the Spallation Neutron Source (SNS) H- ion sources

    SciTech Connect

    Han, Baoxi; Welton, Robert F; Murray Jr, S N; Pennisi, Terry R; Santana, Manuel; Stockli, Martin P

    2014-01-01

    An RF-driven, Cs-enhanced H- ion source feeds the SNS accelerator with a high current (typically >50 mA), ~1.0 ms pulsed beam at 60 Hz. To achieve the persistent high current beam for several weeks long service cycles, each newly installed ion source undergoes a rigorous conditioning and cesiation processes. Plasma conditioning outgases the system and sputter-cleans the ion conversion surfaces. A cesiation process immediately following the plasma conditioning releases Cs to provide coverage on the ion conversion surfaces. The effectiveness of the ion source conditioning and cesiation is monitored with plasma emission spectroscopy using a high-sensitivity optical spectrometer. Plasma emission spectroscopy is also used to provide a mean for diagnosing and confirming a failure of the insulating coating of the ion source RF antenna which is immersed in the plasma. Emissions of composition elements of the antenna coating material, Na emission being the most significant, drastically elevate to signal a failure when it happens. Plasma spectra of the developmental ion source with an AlN chamber and an external RF antenna are also briefly discussed.

  5. Webinar Presentation: Characterization of Emissions from Small, Variable Solid Fuel Combustion Sources for Determining Global Emissions and Climate Impact

    EPA Pesticide Factsheets

    This presentation, Characterization of Emissions from Small, Variable Solid Fuel Combustion Sources for Determining Global Emissions and Climate Impact, was given at the STAR Black Carbon 2016 Webinar Series.

  6. Sulfur Dioxide Emission Rates from Kilauea Volcano, Hawai`i, an Update: 2002-2006

    USGS Publications Warehouse

    Elias, Tamar; Sutton, A.J.

    2007-01-01

    Introduction Sulfur dioxide (SO2) emission rates from Kilauea Volcano were first measured by Stoiber and Malone (1975) and have been measured on a regular basis since 1979 (Greenland and others, 1985; Casadevall and others, 1987; Elias and others, 1998; Sutton and others, 2001, Elias and Sutton, 2002, Sutton and others, 2003). Compilations of SO2 emission-rate and wind-vector data from 1979 through 2001 are available on the web. (Elias and others, 1998 and 2002). This report updates the database through 2006, and documents the changes in data collection and processing that have occurred during the interval 2002-2006. During the period covered by this report, Kilauea continued to release SO2 gas predominantly from its summit caldera and east rift zone (ERZ) (Elias and others, 1998; Sutton and others, 2001, Elias and others, 2002, Sutton and others, 2003). These two distinct sources are always measured independently (fig.1). Sulphur Banks is a minor source of SO2 and does not contribute significantly to the total emissions for Kilauea (Stoiber and Malone, 1975). From 1979 until 2003, summit and east rift zone emission rates were derived using vehicle- and tripod- based Correlation Spectrometry (COSPEC) measurements. In late 2003, we began to augment traditional COSPEC measurements with data from one of the new generation of miniature spectrometer systems, the FLYSPEC (Horton and others, 2006; Elias and others, 2006, Williams-Jones and others, 2006).

  7. Microwave subsecond pulses in solar flares - source localization, emission mechanism

    NASA Astrophysics Data System (ADS)

    Altyntsev, A. T.; Kardapolova, N. N.; Kuznetsov, A. A.; Lesovoi, S. V.; Meshalkina, N. S.; Yan, Y.

    The observations of bursts with fine temporal structures is one of few ways to study the primary energy release sites in solar flares. The localization of their sources in a flare region using the Siberian Solar Radio Telescope data (5.7 GHz) provide us with the unique possibility to determine plasma parameters, and to verify emission mechanisms. The simultaneous spectral observations (5.2 - 7.7 GHz) were provided by National Astronomical Observatories/Beijing spectropolarimeters. An analysis is made of the subsecond pulses of different types: short duration wide band pulses, U-type cm-bursts, the bursts with the "zebra" pattern. The suggestion is justified that in many cases the frequency drifts are response to the plasma density dynamics in the local sites in flare loops. It is argued that the conditions of emission escaping from the source strongly influent the apparent source sizes and the polarization degree of the subsecond sources. This research was supported by Grants 02-02-39030 and 03-02-16229 of RFBR, and E02-3.2-489 of Education department of Russia.

  8. Updated emission inventories for speciated atmospheric mercury from anthropogenic sources in China.

    PubMed

    Zhang, Lei; Wang, Shuxiao; Wang, Long; Wu, Ye; Duan, Lei; Wu, Qingru; Wang, Fengyang; Yang, Mei; Yang, Hai; Hao, Jiming; Liu, Xiang

    2015-03-03

    China is the largest contributor to global atmospheric mercury (Hg), and accurate emission inventories in China are needed to reduce large gaps existing in global Hg mass balance estimates and assess Hg effects on various ecosystems. The China Atmospheric Mercury Emission (CAME) model was developed in this study using probabilistic emission factors generated from abundant on-site measurements and literature data. Using this model, total anthropogenic Hg emissions were estimated to be continuously increasing from 356 t in 2000 to 538 t in 2010 with an average annual increase rate of 4.2%. Industrial coal combustion, coal-fired power plants, nonferrous metal smelting, and cement production were identified to be the dominant Hg emission sources in China. The ten largest contributing provinces accounted for nearly 60% of the total Hg emissions in 2010. Speciated Hg emission inventory was developed over China with a grid-resolution of 36 × 36 km, providing needed emission fields for Hg transport models. In this new inventory, the sectoral Hg speciation profiles were significantly improved based on the latest data from field measurements and more detailed technology categorization. The overall uncertainties of the newly developed inventory were estimated to be in the range of -20% to +23%.

  9. Quantification of methane emission rates from coal mine ventilation shafts using airborne remote sensing data

    NASA Astrophysics Data System (ADS)

    Krings, T.; Gerilowski, K.; Buchwitz, M.; Hartmann, J.; Sachs, T.; Erzinger, J.; Burrows, J. P.; Bovensmann, H.

    2012-10-01

    The quantification of emissions of the greenhouse gas methane is essential for attributing the roles of anthropogenic activity and natural phenomena in global climate change. Our current measurement systems and networks whilst having improved during the last decades, are deficient in many respects. For example, the emissions from localised and point sources such as landfills or fossil fuel exploration sites are not readily assessed. A tool developed to better understand point sources of the greenhouse gases carbon dioxide and methane is the optical remote sensing instrument MAMAP, operated from aircraft. After a recent instrument modification, retrievals of the column averaged dry air mole fractions for methane XCH4 (or for carbon dioxide XCO2) derived from MAMAP data, have a precision of about 0.4% or better and thus can be used to infer emission rate estimates using an optimal estimation inverse Gaussian plume model or a simple integral approach. CH4 emissions from two coal mine ventilation shafts in Western Germany surveyed during the AIRMETH 2011 measurement campaign are used as examples to demonstrate and assess the value of MAMAP data for quantifying CH4 from point sources. While the knowledge of the wind is an important input parameter in the retrieval of emissions from point sources and is generally extracted from models, additional information from a turbulence probe operated on-board the same aircraft was utilised to enhance the quality of the emission estimates. Although flight patterns were optimised for remote sensing measurements, data from an in-situ analyser for CH4 were found to be in good agreement with retrieved dry columns of CH4 from MAMAP and could be used to investigate and refine underlying assumptions for the inversion procedures. With respect to the total emissions of the mine at the time of the overflight, the inferred emission rate of 50.4 kt CH4 yr-1 has a difference of less than 1% compared to officially reported values by the mine

  10. Quantification of methane emission rates from coal mine ventilation shafts using airborne remote sensing data

    NASA Astrophysics Data System (ADS)

    Krings, T.; Gerilowski, K.; Buchwitz, M.; Hartmann, J.; Sachs, T.; Erzinger, J.; Burrows, J. P.; Bovensmann, H.

    2013-01-01

    The quantification of emissions of the greenhouse gas methane is essential for attributing the roles of anthropogenic activity and natural phenomena in global climate change. Our current measurement systems and networks, whilst having improved during the last decades, are deficient in many respects. For example, the emissions from localised and point sources such as landfills or fossil fuel exploration sites are not readily assessed. A tool developed to better understand point sources of the greenhouse gases carbon dioxide and methane is the optical remote sensing instrument MAMAP (Methane airborne MAPper), operated from aircraft. After a recent instrument modification, retrievals of the column-averaged dry air mole fractions for methane XCH4 (or for carbon dioxide XCO2) derived from MAMAP data have a precision of about 0.4% or better and thus can be used to infer emission rate estimates using an optimal estimation inverse Gaussian plume model or a simple integral approach. CH4 emissions from two coal mine ventilation shafts in western Germany surveyed during the AIRMETH 2011 measurement campaign are used as examples to demonstrate and assess the value of MAMAP data for quantifying CH4 from point sources. While the knowledge of the wind is an important input parameter in the retrieval of emissions from point sources and is generally extracted from models, additional information from a turbulence probe operated on-board the same aircraft was utilised to enhance the quality of the emission estimates. Although flight patterns were optimised for remote sensing measurements, data from an in situ analyser for CH4 were found to be in good agreement with retrieved dry columns of CH4 from MAMAP and could be used to investigate and refine underlying assumptions for the inversion procedures. With respect to the total emissions of the mine at the time of the overflight, the inferred emission rate of 50.4 kt CH4 yr-1 has a difference of less than 1% compared to officially

  11. The Sources of F10.7 Emission

    NASA Astrophysics Data System (ADS)

    Schonfeld, S.; White, S. M.; Henney, C. J.; Mcateer, R.; Arge, C. N.

    2013-12-01

    The solar radio flux at a wavelength of 10.7 cm, F10.7, serves as a proxy for the Sun's ionizing flux striking the Earth and is a heavily used index for space weather studies. In principle both the coronal sources of ionizing flux and strong coronal magnetic fields contribute to F10.7 via different emission mechanisms. Recently the Expanded Very Large Array (EVLA) has added the capability to make high-spatial-resolution images of the Sun at 10.7 cm. In this work we compare a trial F10.7 image from the EVLA with the radio emission predicted to be present from EUV images of the Sun acquired by the AIA telescope on the Solar Dynamics Observatory at 6 wavelengths covering the coronal temperature range. Photospheric magnetograms are used to identify likely regions of strong coronal magnetic field, and the circular polarization measured by the EVLA is used as a tracer of gyroresonance contributions to F10.7. We discuss the conversion of the EUV data to bremsstrahlung radio fluxes via the construction of differential emission measure images, and analyze the relative contributions of the different sources of F10.7 flux.

  12. The Sources of F10.7 Emission

    NASA Astrophysics Data System (ADS)

    Schonfeld, Samuel J.; White, Stephen M.; Henney, Carl John; McAteer, James; Arge, Charles

    2014-06-01

    The solar radio flux at a wavelength of 10.7 cm, F10.7, serves as a proxy for the Sun’s ionizing flux striking the Earth and is a heavily used index for space weather studies. In principal both the coronal sources of ionizing flux and strong coronal magnetic fields contribute to F10.7 via different emission mechanisms. Recently the Expanded Very Large Array (EVLA) has added the capability to make high-spatial-resolution images of the Sun at 10.7 cm. In this work we compare a trial F10.7 image from the EVLA with the radio emission predicted to be present from EUV images of the Sun acquired by the AIA telescope on the Solar Dynamics Observatory at 6 wavelengths covering the coronal temperature range. Photospheric magnetograms are used to identify likely regions of strong coronal magnetic field, and the circular polarization measured by the EVLA is used as a tracer of gyroresonance contributions to F10.7. We discuss the conversion of the EUV data to bremsstrahlung radio fluxes via the construction of differential emission measure images, and analyze the relative contributions of the different sources of F10.7 flux.

  13. Scenarios of global mercury emissions from anthropogenic sources

    NASA Astrophysics Data System (ADS)

    Rafaj, P.; Bertok, I.; Cofala, J.; Schöpp, W.

    2013-11-01

    This paper discusses the impact of air quality and climate policies on global mercury emissions in the time horizon up to 2050. Evolution of mercury emissions is based on projections of energy consumption for a scenario without any global greenhouse gas mitigation efforts, and for a 2 °C climate policy scenario, which assumes internationally coordinated action to mitigate climate change. The assessment takes into account current air quality legislation in each country, as well as provides estimates of maximum feasible reductions in mercury through 2050. Results indicate significant scope for co-benefits of climate policies for mercury emissions. Atmospheric releases of mercury from anthropogenic sources under the global climate mitigation regime are reduced in 2050 by 45% when compared to the case without climate measures. Around one third of world-wide co-benefits for mercury emissions by 2050 occur in China. An annual Hg-abatement of about 800 tons is estimated for the coal combustion in power sector if the current air pollution legislation and climate policies are adopted in parallel.

  14. A fast source for quantitative acoustic emission and its application

    NASA Astrophysics Data System (ADS)

    Masaki, Ryuji; Takemoto, Mikio; Ono, Kanji

    1999-12-01

    We demonstrate a new artificial fracture source for quantitative acoustic emission (AE) characterization. The source utilizes the break-down of silicone oil (or other liquids) placed inside a crack (or a slit). This is a dipole source with a rise time under 0.1 μs. It is much faster than a pencil-lead-break source and allows the calibration of a sensor-structure system to 7-10 MHz. We irradiated a focused Q-switched Nd-YAG laser beam (15 to 90 mJ energy) on silicon placed in a slit on a cylindrical block. The out-of-plane displacement produced by the resultant bulk waves was monitored on the outside surface using a heterodyne-type laser interferometer. This break-down source was employed to determine the transfer functions of an AE transducer and propagation medium. Finally, we studied AE signals due to the delayed fracture of a butt-welded dual-phase stainless steel, using the break-down source for calibration. Brittle-fracture events were successfully characterized.

  15. 75 FR 63259 - Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-14

    ... improve data accessibility and increase the ease and efficiency of reporting for sources. Specifically, we... data to WebFIRE electronically is that these data would improve greatly the overall quality of the..., time and money and work to improve the quality of emission inventories and related regulatory...

  16. 76 FR 15371 - Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-21

    ...This action promulgates EPA's new source performance standards and emission guidelines for sewage sludge incineration units located at wastewater treatment facilities designed to treat domestic sewage sludge. This final rule sets limits for nine pollutants under section 129 of the Clean Air Act: Cadmium, carbon monoxide, hydrogen chloride, lead, mercury, nitrogen oxides, particulate matter,......

  17. What could have caused pre-industrial biomass burning emissions to exceed current rates?

    NASA Astrophysics Data System (ADS)

    van der Werf, G. R.; Peters, W.; van Leeuwen, T. T.; Giglio, L.

    2012-08-01

    Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. Here we have analyzed how emissions from several biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary fire emissions and the TM5 chemical transport model, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g. fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture matching current levels despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation; we show that the majority of savannas have not burned in the past 10 yr, even in Africa which

  18. What could have caused pre-industrial biomass burning emissions to exceed current rates?

    NASA Astrophysics Data System (ADS)

    van der Werf, G. R.; Peters, W.; van Leeuwen, T. T.; Giglio, L.

    2013-01-01

    Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary landscape fire emissions and the TM5 chemical transport model driven by present-day atmospheric transport and OH concentrations, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various landscape biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g., fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data, all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture exceeding current levels, despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation

  19. Current Methodologies in Preparing Mobile Source Port-Related Emission Inventories Final Report April 2009

    EPA Pesticide Factsheets

    This report focuses on mobile emission sources at ports, including oceangoing vessels (OGVs), harbor craft, and cargo handling equipment (CHE), as well as other land-side mobile emission sources at ports, such as locomotives and on-highway vehicles.

  20. REVISED EMISSIONS ESTIMATION METHODOLOGIES FOR INDUSTRIAL, RESIDENTIAL, AND ELECTRIC UTILITY STATIONARY COMBUSTION SOURCES

    EPA Science Inventory

    The report describes the development of improved and streamlined EPA emission estimation methods for stationary combustion area sources by the Joint Emissions Inventory Oversight Group (JEIOG) research program. These sources include categories traditionally labeled "other statio...

  1. Odd-even staggering of heavy cluster spontaneous emission rates

    NASA Astrophysics Data System (ADS)

    Poenaru, D. N.; Greiner, W.; Ivaşcu, M.; Mazilu, D.; Plonski, I. H.

    1986-12-01

    Experimentally observed enhanced14C and24Ne emission rates from even-even parents in comparison with that from even-odd or odd-even nuclei are explained in the framework of the analytical superasymmetric fission model, by taking various prescriptions for the zero point vibration energy of even-even, even-odd, odd-even and odd-odd emitters. Longer half-lives than previously computed are obtained by extrapolating the present prescriptions to emitted clusters heavier than24Ne.

  2. 76 FR 15553 - National Emission Standards for Hazardous Air Pollutants for Area Sources: Industrial, Commercial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-21

    ...EPA is promulgating national emission standards for control of hazardous air pollutants from two area source categories: Industrial boilers and commercial and institutional boilers. The final emission standards for control of mercury and polycyclic organic matter emissions from coal-fired area source boilers are based on the maximum achievable control technology. The final emission standards......

  3. Effects of mass airflow rate through an open-circuit gas quantification system when measuring carbon emissions.

    PubMed

    Gunter, Stacey A; Bradford, James A; Moffet, Corey A

    2017-01-01

    Methane (CH) and carbon dioxide (CO) represent 11 and 81%, respectively, of all anthropogenic greenhouse gas emissions. Agricultural CH emissions account for approximately 43% of all anthropogenic CH emissions. Most agricultural CH emissions are attributed to enteric fermentation within ruminant livestock; hence, the heightened interest in quantifying and mitigating this source. The automated, open-circuit gas quantification system (GQS; GreenFeed, C-Lock, Inc., Rapid City, SD) evaluated here can be placed in a pasture with grazing cattle and can measure their CH and CO emissions with spot sampling. However, improper management of the GQS can have an erroneous effect on emission estimates. One factor affecting the quality of emission estimates is the airflow rates through the GQS to ensure a complete capture of the breath cloud emitted by the animal. It is hypothesized that at lower airflow rates this cloud will be incompletely captured. To evaluate the effect of airflow rate through the GQS on emission estimates, a data set was evaluated with 758 CO and CH emission estimates with a range in airflows of 10.7 to 36.6 L/s. When airflow through the GQS was between 26.0 and 36.6 L/s, CO and CH emission estimates were not affected ( = 0.14 and 0.05, respectively). When airflow rates were less than 26.0 L/s, CO and CH emission estimates were lower and decreased as airflow rate decreased ( < 0.0001). We hypothesize that when airflow through the GQS decreases below 26 L/s, breath capture was incomplete and CO and CH emissions are underestimated. Maintaining mass airflow through a GQS at rates greater than 26 L/s is important for producing high quality CO and CH emission estimates.

  4. 75 FR 42676 - National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters; National... Boilers; Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources... Boilers and Process Heaters located at major sources; Industrial, Commercial, and Institutional...

  5. Biosolid stockpiles are a significant point source for greenhouse gas emissions.

    PubMed

    Majumder, Ramaprasad; Livesley, Stephen J; Gregory, David; Arndt, Stefan K

    2014-10-01

    The wastewater treatment process generates large amounts of sewage sludge that are dried and then often stored in biosolid stockpiles in treatment plants. Because the biosolids are rich in decomposable organic matter they could be a significant source for greenhouse gas (GHG) emissions, yet there are no direct measurements of GHG from stockpiles. We therefore measured the direct emissions of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) on a monthly basis from three different age classes of biosolid stockpiles at the Western Treatment Plant (WTP), Melbourne, Australia, from December 2009 to November 2011 using manual static chambers. All biosolid stockpiles were a significant point source for CH4 and N2O emissions. The youngest biosolids (<1 year old) had the greatest CH4 and N2O emissions of 60.2 kg of CO2-e per Mg of biosolid per year. Stockpiles that were between 1 and 3 years old emitted less overall GHG (∼29 kg CO2-e Mg(-1) yr(-1)) and the oldest stockpiles emitted the least GHG (∼10 kg CO2-e Mg(-1) yr(-1)). Methane emissions were negligible in all stockpiles but the relative contribution of N2O and CO2 changed with stockpile age. The youngest stockpile emitted two thirds of the GHG emission as N2O, while the 1-3 year old stockpile emitted an equal amount of N2O and CO2 and in the oldest stockpile CO2 emissions dominated. We did not detect any seasonal variability of GHG emissions and did not observe a correlation between GHG flux and environmental variables such as biosolid temperature, moisture content or nitrate and ammonium concentration. We also modeled CH4 emissions based on a first order decay model and the model based estimated annual CH4 emissions were higher as compared to the direct field based estimated annual CH4 emissions. Our results indicate that labile organic material in stockpiles is decomposed over time and that nitrogen decomposition processes lead to significant N2O emissions. Carbon decomposition favors CO2 over

  6. Mapping Fugitive Gas Emission Sources and Severity Across Southeastern Saskatchewan

    NASA Astrophysics Data System (ADS)

    Baillie, J.; Risk, D. A.; Lavoie, M.; Williams, J. P.

    2015-12-01

    Southeastern Saskatchewan, Canada contains a 10,000 km2 region heavily developed by oil and gas activity that has been struggling with air quality issues, arising from hundreds or thousands of oil and gas leak points. The region is also very diverse in terms of oilfield operators, who use extraction techniques including conventional, enhanced oil recovery (EOR), and fracking. As regulators and operators need more knowledge about emission patterns locally, we undertook comprehensive mapping and characterization of leak sources at the regional scale using vehicle-based data collection, together with computational techniques. We measured the presence and source of fugitive emissions from infrastructure and oilfield activities in eight 100 km2 survey domains. These included two controls with no oil and gas activity, and otherwise the domains were selected to capture the diversity of development; targeting primarily conventional and EOR activities in the Weyburn-Midale beds, and unconventional activities in the Bakken play. A total of 25 unique operators fell within the survey domains. Each domain was surveyed multiple times for CO2, CH4, and H2S, allowing us to identify persistent leaks and to screen out one-time events. The multiple gas targets also provided opportunities for discriminating one type of fugitive emission from another (i.e. flares from storage tanks) using ratios of excess (above ambient) concentrations, after correcting for natural background variability with a signal-processing routine. Fugitive emissions were commonly observed in all study domains. Most emissions were associated with oil and gas infrastructure, as opposed to drilling and other short-term activities. There were obvious emissions at many well pads, storage tanks, and flares. We also observed high geochemical variability around flares, with some being very effective in combusting toxic gases, and others less so. Almost all observed concentrations fell below regulatory limits, but have a

  7. Urban sources and emissions of nitrous oxide and methane in southern California, USA

    NASA Astrophysics Data System (ADS)

    Townsend-Small, A.; Pataki, D.; Tyler, S. C.; Czimczik, C. I.; Xu, X.; Christensen, L. E.

    2012-12-01

    Anthropogenic activities have resulted in increasing levels of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. While global and regional emissions sources of carbon dioxide are relatively well understood, methane and nitrous oxide are less constrained, particularly at regional scales. Here we present the results of an investigation of sources and emissions of methane and nitrous oxide in Los Angeles, California, USA, one of Earth's largest urban areas. The original goal of the project was to determine whether isotopes are useful tracers of agricultural versus urban nitrous oxide and methane sources. For methane, we found that stable isotopes (carbon-13 and deuterium) and radiocarbon are good tracers of biogenic versus fossil fuel sources. High altitude observations of methane concentration, measured continuously using tunable laser spectroscopy, and isotope ratios, measured on discrete flask samples using mass spectrometry, indicate that the predominant methane source in Los Angeles is from fossil fuels, likely from "fugitive" emissions from geologic formations, natural gas pipelines, oil refining, or power plants. We also measured nitrous oxide emissions and isotope ratios from urban (landscaping and wastewater treatment) and agricultural sources (corn and vegetable fields). There was no difference in nitrous oxide isotope ratios between the different types of sources, although stable isotopes did differ between nitrous oxide produced in oxic and anoxic wastewater treatment tanks. Our nitrous oxide flux data indicate that landscaped turfgrass emits nitrous oxide at rates equivalent to agricultural systems, indicating that ornamental soils should not be disregarded in regional nitrous oxide budgets. However, we also showed that wastewater treatment is a much greater source of nitrous oxide than soils regionally. This work shows that global nitrous oxide and methane budgets are not easily downscaled to regional, urban settings, which has

  8. Characterizing the isotopic composition of atmospheric ammonia emission sources using passive samplers and a combined oxidation-bacterial denitrifier approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ammonia (NH3) emissions are a substantial source of nitrogen pollution to sensitive terrestrial, aquatic, and marine ecosystems. Dependable quantification of NH3 sources is of growing importance due to recently observed increases in ammonium (NH4+) deposition rates that are directly proportional to ...

  9. 40 CFR 63.5984 - What emission limits must I meet for tire production affected sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... tire production affected sources? 63.5984 Section 63.5984 Protection of Environment ENVIRONMENTAL... POLLUTANTS FOR SOURCE CATEGORIES National Emissions Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984 What emission limits must I...

  10. Near-field beamforming analysis for acoustic emission source localization.

    PubMed

    He, Tian; Pan, Qiang; Liu, Yaoguang; Liu, Xiandong; Hu, Dayong

    2012-07-01

    This paper attempts to introduce a near-field acoustic emission (AE) beamforming method to estimate the AE source locations by using a small array of sensors closely placed in a local region. The propagation characteristics of AE signals are investigated based on guided wave theory to discuss the feasibility of using beamforming techniques in AE signal processing. To validate the effectiveness of the AE beamforming method, a series of pencil lead break tests at various regions of a thin steel plate are conducted. The potential of this method for engineering applications are explored through rotor-stator rubbing tests. The experimental results demonstrate that the proposed method can effectively determine the region where rubbing occurs. It is expected that the work of this paper may provide a helpful analysis tool for near-field AE source localization.

  11. Measurements of Point Source Methane Emissions in the Barnett Shale and Eagle Ford Basins

    NASA Astrophysics Data System (ADS)

    Lavoie, T. N.; Shepson, P. B.; Cambaliza, M. O. L.; Karion, A.; Sweeney, C.; Kort, E. A.; Hirst, B.; Wolter, S.; Conley, S. A.; Faloona, I. C.; Lyon, D.; Alvarez, R.

    2014-12-01

    The global average temperature is rising as a result of anthropogenic emissions of greenhouse gases. The two organic carbon gases that contribute most to this warming are carbon dioxide (CO2) and methane (CH4). CH4, however, is 34 times more potent as a greenhouse gas than CO2 on a 100-year timescale, and 86 times more potent on a 20-year timescale. The ~12 year lifetime of CH4 means that measures to control methane emissions on the near-term time scale may have a relatively large climate benefit. The past decade has witnessed a dramatic increase in the reliance on natural gas (NG) to meet the energy needs of the U.S. To enable informed greenhouse gas policy and mitigation efforts, a comprehensive understanding of the nature and magnitude of CH4 emissions for various related NG technologies and engineering practices is required. Here we report results of our recent studies of the CH4 emission rate observed at eight different biogenic and NG point sources in the Barnett shale basin and a dozen well pads in the Eagle Ford shale region of Texas. We compare our field measurements to reported inventory estimates from the Greenhouse Gas Reporting Program (GHGRP). Using an aircraft-based mass balance approach, we found that the summed observed CH4 emission rates for our study sites were a factor of 2.5 to 4.5 greater than the GHGRP-based estimates, for the 8 sources we investigated in the Barnett shale region. The sum of the 5 Barnett NG sources we quantified had on average CH4 emissions 17.5X higher than the GHGRP inventory indicates. The sum of the 3 landfill emission rates were on average 1.5X greater than the inventory values. In the Eagle Ford shale region, high variability was observed in repeated measurements at the same well pads, highlighting the difficulty of assessing the character and statistics of the distribution of emissions from individual pads. These results indicate a need for better methods of emissions monitoring and reporting and highlight the

  12. The Sources of F10.7 Emission

    NASA Astrophysics Data System (ADS)

    Schonfeld, Samuel; White, Stephen; Henney, Carl; Arge, Nick; McAteer, James

    2015-04-01

    The solar radio flux at a wavelength of 10.7 cm, F10.7, serves as a proxy for the Sun’s ionizing flux striking the Earth and is a heavily used index for space weather studies. In principal both the coronal sources of ionizing flux and strong coronal magnetic fields contribute to F10.7 via the bremsstrahlung and gyroresonance mechanisms respectively. Recently the Karl G. Jansky Very Large Array (JVLA) has added the capability to make high-spatial-resolution images of the Sun at 10.7 cm. We present the results of a trial study comparing an F10.7 image from the JVLA with the bremsstrahlung emission predicted to be present. The predicted bremsstrahlung image is calculated with spatially resolved differential emission measures derived from extreme ultra-violet images of the Sun acquired by the Atmospheric Imaging Assembly. Photospheric magnetograms are used to identify likely regions of strong coronal magnetic field, and the circular polarization measured by the JVLA is used as a tracer of gyroresonance contributions. We find that only a small fraction of the variable F10.7 flux can be attributed to gyroresonance emission.

  13. PAH Clusters as Sources of Interstellar Infrared Emission

    NASA Astrophysics Data System (ADS)

    Roser, J. E.; Ricca, A.

    2015-03-01

    Polycyclic aromatic hydrocarbons (or PAHs) have been the subject of astrochemical research for several decades as principal sources of the interstellar aromatic infrared emission bands. PAH clusters could possibly contribute to these emission bands, but a lack of data on their infrared properties has made this hypothesis difficult to evaluate. Here we investigate homogeneous neutral PAH clusters by measuring the mid-infrared absorption spectra of the five nonlinear PAH molecules phenanthrene, chrysene, pyrene, perylene, and benzo[ghi]perylene within solid argon ice at a fixed temperature of 5 K. We attribute observed spectral shifts in their principal absorption bands as a function of argon/PAH ratio to clustering of the PAH molecules within the argon matrix. These shifts are related to the cluster structures forming in the matrix and the topology of the monomer PAH molecule. We predict that interstellar PAH molecules that are relatively large (no fewer than 50 carbon atoms per molecule) and compact will have clusters that contribute to the asymmetrically red-shaded profile of the interstellar 11.2 μm emission band.

  14. Sources and emission of greenhouse gases in Danube Delta lakes.

    PubMed

    Pavel, Alina; Durisch-Kaiser, Edith; Balan, Sorin; Radan, Silviu; Sobek, Sebastian; Wehrli, Bernhard

    2009-08-01

    Production of methane and carbon dioxide as well as methane concentrations in surface waters and emissions to the atmosphere were investigated in two flow-through lake complexes (Uzlina-Isac and Puiu-Rosu-Rosulet) in the Danube Delta during post-flood conditions in May and low water level in September 2006. Retained nutrients fueled primary production and remineralization of bioavailable organic matter. This led to an observable net release of methane, particularly in the lakes Uzlina, Puiu and Rosu in May. Input from the Danube River, from redbuds and benthic release contributed to CH(4) concentrations in surface waters. In addition to significant river input of CO(2), this trace gas was released via aerobic remineralization within the water column and in top sediments. Emission patterns of CO(2) widely overlapped with those of CH(4). Generally, greenhouse gas emissions peaked in the lake complex adjacent to the Danube River in May due to strong winds and decreased with increasing hydrological distance from the Danube River. Intense remineralization of organic matter in the Danube Delta lakes results in a net source of atmospheric greenhouse gases.

  15. POLYCYCLIC AROMATIC HYDROCARBON CLUSTERS AS SOURCES OF INTERSTELLAR INFRARED EMISSION

    SciTech Connect

    Roser, J. E.; Ricca, A.

    2015-03-10

    Polycyclic aromatic hydrocarbons (or PAHs) have been the subject of astrochemical research for several decades as principal sources of the interstellar aromatic infrared emission bands. PAH clusters could possibly contribute to these emission bands, but a lack of data on their infrared properties has made this hypothesis difficult to evaluate. Here we investigate homogeneous neutral PAH clusters by measuring the mid-infrared absorption spectra of the five nonlinear PAH molecules phenanthrene, chrysene, pyrene, perylene, and benzo[ghi]perylene within solid argon ice at a fixed temperature of 5 K. We attribute observed spectral shifts in their principal absorption bands as a function of argon/PAH ratio to clustering of the PAH molecules within the argon matrix. These shifts are related to the cluster structures forming in the matrix and the topology of the monomer PAH molecule. We predict that interstellar PAH molecules that are relatively large (no fewer than 50 carbon atoms per molecule) and compact will have clusters that contribute to the asymmetrically red-shaded profile of the interstellar 11.2 μm emission band.

  16. Characterization of gaseous pollutant and particulate matter emission rates from a commercial broiler operation part I: Observed trends in emissions

    NASA Astrophysics Data System (ADS)

    Roumeliotis, Taylor S.; Dixon, Brad J.; Van Heyst, Bill J.

    2010-10-01

    This paper characterizes the emission rates of size fractionated particulate matter, inorganic aerosols, acid gases, ammonia and methane measured over four flocks at a commercial broiler chicken facility. Mean emission rates of each pollutant, along with sampling notes, were reported in this paper, the first in a series of two. Sampling notes were needed because inherent gaps in data may bias the mean emission rates. The mean emission rates of PM 10 and PM 2.5 were 5.0 and 0.78 g day -1 [Animal Unit, AU] -1, respectively, while inorganic aerosols mean emission rates ranged from 0.15 to 0.46 g day -1 AU -1 depending on the season. The average total acid gas emission rate was 0.43 g day -1 AU -1 with the greatest contribution from nitrous and nitric acids and little contribution from sulfuric acid (as SO 2). Ammonia emissions were seasonally dependent, with a mean emission rate of 66.0 g day -1 AU -1 in the cooler seasons and 94.5 g day -1 AU -1 during the warmer seasons. Methane emissions were relatively consistent with a mean emission rate of 208 g day -1 AU -1. The diurnal pattern in each pollutant's emission rate was relatively consistent after normalizing the hourly emissions according to each daily mean emission rate. Over the duration of a production cycle, all the measured pollutants' emissions increased proportionally to the total live mass of birds in the house, with the exception of ammonia. Interrelationships between pollutants provide evidence of mutually dependent release mechanisms, which suggests that it may be possible to fill data gaps with minimal data requirements. In the second paper (Roumeliotis, T.S., Dixon, B.J., Van Heyst, B.J. Characterization of gaseous pollutants and particulate matter emission rates from a commercial broiler operation part II: correlated emission rates. Atmospheric Environment, 2010.), regression correlations are developed to estimate daily mean emission rates for data gaps and, using the normalized hourly diurnal

  17. Nitrogen placement and source effects on nitrous oxide emissions and yields of irrigated corn.

    PubMed

    Halvorson, Ardell D; Del Grosso, Stephen J

    2013-01-01

    Limited information is available on how N fertilizer placement affects soil nitrous oxide (NO) emissions under irrigated conditions in the semiarid western United States. Our objective was to compare surface banding near corn row and broadcasting of three N sources (urea, polymer-coated urea [PCU], and stabilized urea [SU] containing urease and nitrification inhibitors) on NO emissions from a clay loam soil under sprinkler-irrigated continuous corn production. The N fertilizers were applied at a rate of 202 kg N ha to strip-till (2010 and 2011) and no-till (2011) corn at crop emergence, with ∼19 mm irrigation water applied the next day. Band-applied N had a 1.46-fold greater NO emission than broadcast N averaged over N sources and three studies. Soil NO-N emissions from urea were 1.48- and 1.74-fold greater than from PCU and SU, respectively, when averaged over N placement and studies. The N placement × source interaction was not significant. Averaged across studies, grain yield and N uptake did not vary with N placement, whereas grain yields were greater for SU than PCU but were not different from urea. Nitrous oxide emissions per unit of N applied, per unit of grain yield, and per unit N uptake were 59, 49, and 47% greater, respectively, with banded than with broadcast N fertilizer. These studies show that N placement and N source selection are important manageable factors that can affect NO emissions and need to be considered when developing NO mitigation practices in irrigated cropping systems in the semiarid western United States.

  18. Atmospheric Modeling and Verification of Point Source Fossil Fuel CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Keller, E. D.; Turnbull, J. C.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.; Norris, M. W.; Zondervan, A.

    2014-12-01

    Emissions from large point sources (electricity generation and large-scale industry) of fossil fuel CO2 (CO2ff) emissions are currently determined from self-reported "bottom-up" inventory data, with an uncertainty of about 20% for individual power plants. As the world moves towards a regulatory environment, there is a need for independent, objective measurements of these emissions both to improve the accuracy of and to verify the reported amounts. "Top-down" atmospheric methods have the potential to independently constrain point source emissions, combining observations with atmospheric transport modeling to derive emission estimates. We use the Kapuni Gas Treatment Plant to examine methodologies and model sensitivities for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes and vents CO2 from locally extracted natural gas at a rate of ~0.1 Tg carbon per year. We measured the CO2ff content in three different types of observations: air samples collected in flasks over a period of a few minutes, sodium hydroxide solution exposed the atmosphere, and grass samples from the surrounding farmland, the latter two representing ~1 week integrated averages. We use the WindTrax Lagrangian plume dispersion model to compare these atmospheric observations with "expected" values given the emissions reported by the Kapuni plant. The model has difficulty accurately capturing the short-term variability in the flask samples but does well in representing the longer-term averages from grass samples, suggesting that passive integrated-sampling methods have the potential to monitor long-term emissions. Our results indicate that using this method, point source emissions can be verified to within about 30%. Further improvements in atmospheric transport modelling are needed to reduce uncertainties. In view of this, we discuss model strengths and weaknesses and explore model sensitivity to meteorological conditions

  19. Neutron-emission measurements at a white neutron source

    SciTech Connect

    Haight, Robert C

    2010-01-01

    Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

  20. High rates of anaerobic methane oxidation in freshwater wetlands reduce potential atmospheric methane emissions.

    PubMed

    Segarra, K E A; Schubotz, F; Samarkin, V; Yoshinaga, M Y; Hinrichs, K-U; Joye, S B

    2015-06-30

    The role of anaerobic oxidation of methane (AOM) in wetlands, the largest natural source of atmospheric methane, is poorly constrained. Here we report rates of microbially mediated AOM (average rate=20 nmol cm(-3) per day) in three freshwater wetlands that span multiple biogeographical provinces. The observed AOM rates rival those in marine environments. Most AOM activity may have been coupled to sulphate reduction, but other electron acceptors remain feasible. Lipid biomarkers typically associated with anaerobic methane-oxidizing archaea were more enriched in (13)C than those characteristic of marine systems, potentially due to distinct microbial metabolic pathways or dilution with heterotrophic isotope signals. On the basis of this extensive data set, AOM in freshwater wetlands may consume 200 Tg methane per year, reducing their potential methane emissions by over 50%. These findings challenge precepts surrounding wetland carbon cycling and demonstrate the environmental relevance of an anaerobic methane sink in ecosystems traditionally considered strong methane sources.

  1. Modal acoustic emission source determination in silicon carbide matrix composites

    NASA Astrophysics Data System (ADS)

    Morscher, G. N.

    2000-05-01

    Modal acoustic emission has been used to monitor damage accumulation in woven silicon carbide (SiC) fiber reinforced SiC matrix composites during tensile testing. There are several potential sources of damage in these systems including transverse matrix cracking, fiber/matrix interphase debonding and sliding, longitudinal cracks in between plies, and fiber breakage. In the past, it has been shown that modal AE is excellent at detecting when damage occurs and subsides, where the damage occurs along the length of the sample, and the loss in material stiffness as a consequence of damage accumulation. The next step is to determine the extent that modal AE can be used to identify specific physical sources. This study will discuss the status of this aim for this composite system. Individual events were analyzed and correlated to specific sources based on the characteristics of the received waveforms, e.g., frequency spectrum and energy, and when the event occurred during the stress-history of the tensile test. Post-test microstructural examination of the test specimens enabled some correlation between specific types of AE events and damage sources.

  2. Smog O3 Production Rate in California Air: Marker Compounds Allow Checks on Source Attribution to Fire and Other Sources

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Esswein, R. F.; Cai, C.; Kaduwela, A.; Kulkarni, S.; Blake, D. R.; Weinheimer, A. J.; Fried, A.; Huey, L. G.

    2012-12-01

    We are able to attribute sources of both radical reactivity and NO that determined the smog-chemical production rate of ozone, P(O3), for NASA's wide-ranging sampling of California air in June, 2008, part of the ARCTAS intensive. We relate formaldehyde, HCHO, and reactive nitrogen oxides, NOx, to a variety of distinct "marker" species that identify origins. We have labeled the sources and markers as (i) Fire emissions (CH3CN), (ii) Biogenic emissions (Isoprene), (iii) Urban/business emissions (CHCl3), (iv) Transport-related fuel consumption, (SO2), and (v) Refining/Port emissions ("residual" toluene). We use multiple linear regression with some appropriate restrictions. We achieve R-squared or explained variance of 88% for HCHO (VOC's) and 60% for NOx. HCHO and NOx are slowly evolving measures of potential ozone generation. The two related but radiation-influenced measures j (HCHO->H+HCO) x [HCHO] and [NO] quantitatively, but non-linearly, relate to instantaneous ozone production in California air, with R-squared of 86-93%, just as in New York City (Chatfield et al., Atmos. Environ., 2010). Maps of attribution for 650 samples from the Port of San Diego to the Northern Sierra foothills, and offshore -— all show huge variability in source attributions for VOCs and NOx. They indicate a widespread fire-emission influence on VOCs as they produce peroxy radicals, but show no positive influence on NOx, in fact consuming NOx from other sources. Comparisons with simulations help to refine our attribution classes and also to check balances of VOC emissions in available inventories. The use of the P(O3) measures is directly translatable to a method for estimate smog-ozone production rate from space, as data from another intensive, DISCOVER-AQ, show. (Left) A rare example where all sources contribute significantly, with markers and tentative attributions marked. (Right) Three different situations describing the control of smog ozone production, all from the same geographic

  3. Mercury emissions to the atmosphere from natural and anthropogenic sources in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Pirrone, N.; Costa, P.; Pacyna, J. M.; Ferrara, R.

    This report discusses past, current and projected mercury emissions to the atmosphere from major industrial sources, and presents a first assessment of the contribution to the regional mercury budget from selected natural sources. Emissions (1995 estimates) from fossil fuels combustion (29.8 t yr -1) , cement production (28.8 t yr -1) and incineration of solid wastes (27.6 t yr -1) , all together account for about 82% of the regional anthropogenic total (105.7 t yr -1) . Other industrial sources in the region are smelters (4.8 t yr -1) , iron-steel plants (4.8 t yr -1) and other minor sources (chlor-alkali plants, crematoria, chemicals production) that have been considered together in the miscellaneous category (9.6 t yr -1) . Regional emissions from anthropogenic sources increased at a rate of 3% yr-1 from 1983 to 1995 and are projected to increase at a rate of 1.9% yr-1 in the next 25 years, if no improvement in emission control policy occurs. On a country-by-country basis, France is the leading emitter country with 22.6 t yr -1 followed by Turkey (16.1 t yr -1) , Italy (11.4 t yr -1) , Spain (9.1 t yr -1) , the former Yugoslavia 7.9 ( t yr -1) , Morocco (6.9 t yr -1) , Bulgaria (6.8 t yr -1) , Egypt (6.1 t yr -1) , Syria (3.6 t yr -1) , Libya (2.9 t yr -1) , Tunisia (2.8 t yr -1) and Greece (2.7 t yr -1) , whereas the remaining countries account for less than 7% of the regional total. The annual emission from natural sources is 110 t yr -1, although this figure only includes the volatilisation of elemental mercury from surface waters and emissions from volcanoes, whereas the contribution due to the degassing of mercury from top soil and vegetation has not been included in this first assessment. Therefore, natural and anthropogenic sources in the Mediterranean region release annually about 215 t of mercury, which represents a significant contribution to the total mercury budget released in Europe and to the global atmosphere.

  4. Atmospheric dispersion modeling with AERMOD for comparative impact assessment of different pollutant emission sources in an Alpine context

    NASA Astrophysics Data System (ADS)

    Antonacci, Gianluca; Giovannini, Lorenzo; Tomasi, Elena; Zardi, Dino

    2015-04-01

    High-resolution simulations are performed with the AERMOD model to analyze the impact on air quality of different pollutant emission sources in the area surrounding the town of Vipiteno in the northeastern Italian Alps. In this area the environmental burden of pollutant emissions is particularly high because of both its complex terrain and the presence of specific pollutant sources. In this study the effects of the main sources are analyzed and compared: the A22 motorway, which leads to the Brenner pass, the town of Vipiteno, mainly characterized by intensive use of biomass for house heating, three major plants with high emission rates, and a parking lot located near the motorway, offering park spaces for up to 260 trucks and 50 cars. To assess the impact of these pollution sources the AERMOD model is run with a spatial resolution of 25 m and with meteorological input data obtained from different datasets, such as annual series of standard meteorological variables taken from local weather stations and a set of vertical soundings. During the simulations the sources are modeled in different ways depending on the type of the emissions: the motorway is modeled as a linear source, the village as a diffuse source, the local companies as point sources and the parking lot is modeled as a composition of a diffuse source, representing the idling vehicles inside the park, and of a linear source, representing the access routes to the parking. For each type of source, specific emission factors are chosen, and hourly and seasonal emission patterns are set with particular attention to the analysis of idling vehicle emission factors. The results of the simulations are analyzed in terms of NO2 and PM10 and the impact of each source is discussed.

  5. Identifying and characterizing major emission point sources as a basis for geospatial distribution of mercury emissions inventories

    NASA Astrophysics Data System (ADS)

    Steenhuisen, Frits; Wilson, Simon J.

    2015-07-01

    Mercury is a global pollutant that poses threats to ecosystem and human health. Due to its global transport, mercury contamination is found in regions of the Earth that are remote from major emissions areas, including the Polar regions. Global anthropogenic emission inventories identify important sectors and industries responsible for emissions at a national level; however, to be useful for air transport modelling, more precise information on the locations of emission is required. This paper describes the methodology applied, and the results of work that was conducted to assign anthropogenic mercury emissions to point sources as part of geospatial mapping of the 2010 global anthropogenic mercury emissions inventory prepared by AMAP/UNEP. Major point-source emission sectors addressed in this work account for about 850 tonnes of the emissions included in the 2010 inventory. This work allocated more than 90% of these emissions to some 4600 identified point source locations, including significantly more point source locations in Africa, Asia, Australia and South America than had been identified during previous work to geospatially-distribute the 2005 global inventory. The results demonstrate the utility and the limitations of using existing, mainly public domain resources to accomplish this work. Assumptions necessary to make use of selected online resources are discussed, as are artefacts that can arise when these assumptions are applied to assign (national-sector) emissions estimates to point sources in various countries and regions. Notwithstanding the limitations of the available information, the value of this procedure over alternative methods commonly used to geo-spatially distribute emissions, such as use of 'proxy' datasets to represent emissions patterns, is illustrated. Improvements in information that would facilitate greater use of these methods in future work to assign emissions to point-sources are discussed. These include improvements to both national

  6. 40 CFR Appendix C to Part 60 - Determination of Emission Rate Change

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... emission rate to the atmosphere. The method used is the Student's t test, commonly used to make inferences... difference between E b and E a is significant, and an increase in emission rate to the atmosphere has... significant, and there has been an increase in emission rate to the atmosphere. 6.Continuous Monitoring Data...

  7. 40 CFR Appendix C to Part 60 - Determination of Emission Rate Change

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... emission rate to the atmosphere. The method used is the Student's t test, commonly used to make inferences... difference between E b and E a is significant, and an increase in emission rate to the atmosphere has... significant, and there has been an increase in emission rate to the atmosphere. 6.Continuous Monitoring Data...

  8. Environmental tobacco smoke: mutagenic emission rates and their relationship to other emission factors

    SciTech Connect

    Lewtas, J.; Williams, K.; Lofroth, G.; Hammond, K.; Leaderer, B.

    1987-05-01

    The objective of this study was to evaluate the emission rates and exposure concentrations of mutagens, nicotine, and particles from cigarettes. Studies were conducted under controlled laboratory and chamber conditions as well as in personal residences. The mutagenicity of environmental tobacco smoke (ETS) was evaluated in three bioassays using two strains of Salmonella typhimurium. Strain TA98 was used in the standard plate-incorporation and microsuspension histidine reversion assays; and strain TM677 in a microsuspension forward mutation assay. The mutagenicity, expressed either per Ug particle or per Ug nicotine, appeared to be a relatively constant factor that did not vary significantly between various cigarette brands. These data are being used to model the emissions of mutagens to predict mutagenic exposure concentrations under various conditions.

  9. Assessment of corrosion rate in prestressed concrete with acoustic emission

    NASA Astrophysics Data System (ADS)

    Mangual, Jesé; ElBatanouny, Mohamed K.; Vélez, William; Ziehl, Paul; Matta, Fabio; González, Miguel

    2011-04-01

    Acoustic Emission (AE) sensing was employed to assess the rate of corrosion of steel strands in small scale concrete block specimens. The corrosion process was accelerated in a laboratory environment using a potentiostat to supply a constant potential difference with a 3% NaCl solution as the electrolyte. The embedded prestressing steel strand served as the anode, and a copper plate served as the cathode. Corrosion rate, half-cell potential measurements, and AE activity were recorded continuously throughout each test and examined to assess the development of corrosion and its rate. At the end of each test the steel strands were cleaned and re-weighed to determine the mass loss and evaluate it vis-á-vis the AE data. The initiation and propagation phases of corrosion were correlated with the percentage mass loss of steel and the acquired AE signals. Results indicate that AE monitoring may be a useful aid in the detection and differentiation of the steel deterioration phases, and estimation of the locations of corroded areas.

  10. Joint source-channel rate allocation in parallel channels.

    PubMed

    Pu, Lingling; Marcellin, Michael W; Djordjevic, Ivan; Vasic, Bane; Bilgin, Ali

    2007-08-01

    A fast rate-optimal rate allocation algorithm is proposed for parallel transmission of scalable images in multichannel systems. Scalable images are transmitted via fixed-length packets. The proposed algorithm selects a subchannel, as well as a channel code rate for each packet, based on the signal-to-noise ratios (SNRs) of the subchannels. The resulting scheme provides unequal error protection of source bits and significant gains are obtained over equal error protection schemes. An application of the proposed algorithm to JPEG2000 transmission shows the advantages of exploiting differences in SNRs between subchannels. Multiplexing of multiple sources is also considered, and additional gains are achieved by exploiting information diversity among the sources.

  11. Quantifying Molecular Hydrogen Emissions and an Industrial Leakage Rate for the South Coast Air Basin of California

    NASA Astrophysics Data System (ADS)

    Irish, M. C.; Schroeder, J.; Beyersdorf, A. J.; Blake, D. R.

    2015-12-01

    The poorly understood atmospheric budget and distribution of molecular hydrogen (H2) have invited further research since the discovery that emissions from a hydrogen-based economy could have negative impacts on the global climate system and stratospheric ozone. The burgeoning fuel cell electric vehicle industry in the South Coast Air Basin of California (SoCAB) presents an opportunity to observe and constrain urban anthropogenic H2 emissions. This work presents the first H2 emissions estimate for the SoCAB and calculates an upper limit for the current rate of leakage from production and distribution infrastructure within the region. A top-down method utilized whole air samples collected during the Student Airborne Research Program (SARP) onboard the NASA DC-8 research aircraft from 23-25 June 2015 to estimate H2 emissions from combustion and non-combustion sources. H2:carbon monoxide (CO) and H2:carbon dioxide ratios from airborne observations were compared with experimentally established ratios from pure combustion source ratios and scaled with the well-constrained CO emissions inventory to yield H2 emissions of 24.9 ± 3.6 Gg a-1 (1σ) from combustion engines and 8.2 ± 4.7 Gg a-1 from non-combustion sources. Total daily production of H2 in the SoCAB was compared with the top-down results to estimate an upper limit leakage rate (5%) where all emissions not accounted for by incomplete combustion in engines were assumed to be emitted from H2 infrastructure. For bottom-up validation, the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory dispersion model was run iteratively with all known stationary sources in attempt to constrain emissions. While this investigation determined that H2 emissions from non-combustion sources in the SoCAB are likely significant, more in-depth analysis is required to better predict the atmospheric implications of a hydrogen economy.

  12. VOC emissions of Grey poplar leaves as affected by salt stress and different N sources.

    PubMed

    Teuber, M; Zimmer, I; Kreuzwieser, J; Ache, P; Polle, A; Rennenberg, H; Schnitzler, J-P

    2008-01-01

    Nitrogen nutrition and salt stress experiments were performed in a greenhouse with hydroponic-cultured, salt-sensitive Grey poplar (Populus x canescens) plants to study the combined influence of different N sources (either 1 mm NO(3) (-) or NH(4)(+)) and salt (up to 75 mm NaCl) on leaf gas exchange, isoprene biosynthesis and VOC emissions. Net assimilation and transpiration proved to be highly sensitive to salt stress and were reduced by approximately 90% at leaf sodium concentrations higher than 1,800 microg Na g dry weight (dw)(-1). In contrast, emissions of isoprene and oxygenated VOC (i.e. acetaldehyde, formaldehyde and acetone) were unaffected. There was no significant effect of combinations of salt stress and N source, and neither NO(3)(-) or NH(4)(+) influenced the salt stress response in the Grey poplar leaves. Also, transcript levels of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (PcDXR) and isoprene synthase (PcISPS) did not respond to the different N sources and only responded slightly to salt application, although isoprene synthase (PcISPS) activity was negatively affected at least in one of two experiments, despite high isoprene emission rates. A significant salt effect was the strong reduction of leaf dimethylallyl diphosphate (DMADP) content, probably due to restricted availability of photosynthates for DMADP biosynthesis. Further consequences of reduced photosynthetic gas exchange and maintaining VOC emissions are a very high C loss, up to 50%, from VOC emissions related to net CO(2) uptake and a strong increase in leaf internal isoprene concentrations, with maximum mean values up to 6.6 microl x l(-1). Why poplar leaves maintain VOC biosynthesis and emission under salt stress conditions, despite impaired photosynthetic CO(2) fixation, is discussed.

  13. Final LDRD report : enhanced spontaneous emission rate in visible III-nitride LEDs using 3D photonic crystal cavities.

    SciTech Connect

    Fischer, Arthur Joseph; Subramania, Ganapathi S.; Coley, Anthony J.; Lee, Yun-Ju; Li, Qiming; Wang, George T.; Luk, Ting Shan; Koleske, Daniel David; Fullmer, Kristine Wanta

    2009-09-01

    The fundamental spontaneous emission rate for a photon source can be modified by placing the emitter inside a periodic dielectric structure allowing the emission to be dramatically enhanced or suppressed depending on the intended application. We have investigated the relatively unexplored realm of interaction between semiconductor emitters and three dimensional photonic crystals in the visible spectrum. Although this interaction has been investigated at longer wavelengths, very little work has been done in the visible spectrum. During the course of this LDRD, we have fabricated TiO{sub 2} logpile photonic crystal structures with the shortest wavelength band gap ever demonstrated. A variety of different emitters with emission between 365 nm and 700 nm were incorporated into photonic crystal structures. Time-integrated and time-resolved photoluminescence measurements were performed to measure changes to the spontaneous emission rate. Both enhanced and suppressed emission were demonstrated and attributed to changes to the photonic density of states.

  14. Indoor acrolein emission and decay rates resulting from domestic cooking events

    NASA Astrophysics Data System (ADS)

    Seaman, Vincent Y.; Bennett, Deborah H.; Cahill, Thomas M.

    2009-12-01

    Acrolein (2-propenal) is a common constituent of both indoor and outdoor air, can exacerbate asthma in children, and may contribute to other chronic lung diseases. Recent studies have found high indoor levels of acrolein and other carbonyls compared to outdoor ambient concentrations. Heated cooking oils produce considerable amounts of acrolein, thus cooking is likely an important source of indoor acrolein. A series of cooking experiments were conducted to determine the emission rates of acrolein and other volatile carbonyls for different types of cooking oils (canola, soybean, corn and olive oils) and deep-frying different food items. Similar concentrations and emission rates of carbonyls were found when different vegetable oils were used to deep-fry the same food product. The food item being deep-fried was generally not a significant source of carbonyls compared to the cooking oil. The oil cooking events resulted in high concentrations of acrolein that were in the range of 26.4-64.5 μg m -3. These concentrations exceed all the chronic regulatory exposure limits and many of the acute exposure limits. The air exchange rate and the decay rate of the carbonyls were monitored to estimate the half-life of the carbonyls. The half-life for acrolein was 14.4 ± 2.6 h, which indicates that indoor acrolein concentrations can persist for considerable time after cooking in poorly-ventilated homes.

  15. Emission rates of sulfur dioxide, trace gases and metals from Mount Erebus, Antartica

    SciTech Connect

    Kyle, P.R.; Meeker, K. ); Finnegan, D. )

    1990-11-01

    SO{sub 2} emission rates have been measured annually since 1983 at Mount Erebus, Antarctica by correlation spectrometer (COSPEC V). Following a 4 month period of sustained strombolian activity in late 1984, SO{sub 2} emissions declined from 230 Mg/day in 1983 to 25 Mg/day and then slowly increased from 16 Mg/day in 1985 to 51 Mg/day in 1987. Nine sets of filter packs containing partcle and {sup 7}LiOH treated filters were collected in the plume in 1986 and analyzed by neutron activation. Using the COSPEC data and measured element/S ratios on the filters, emission rates have been determined for trace gases and metals. The authors infer HCl and HF emissions in 1983 to be about 1200 and 500 Mg/day, respectively. Mt Erebus has therefore been an important source of halogens to the Anarctic atmosphere and could be responsible for excess Cl found in Central Antarctica snow.

  16. X-ray Emission from the Sombrero Galaxy: Discrete Sources

    NASA Astrophysics Data System (ADS)

    Li, Zhiyuan; Spitler, Lee R.; Jones, Christine; Forman, William R.; Kraft, Ralph P.; Di Stefano, Rosanne; Tang, Shikui; Wang, Q. Daniel; Gilfanov, Marat; Revnivtsev, Mikhail

    2010-10-01

    We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L X ≈ 1037 erg s-1 and a field of view covering a galactocentric radius of ~30 kpc (11farcm5), 383 sources are detected. Cross-correlation with Spitler et al.'s catalog of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-ray sources in GCs, presumably low-mass X-ray binaries (LMXBs). Metal-rich GCs are found to have a higher probability of hosting these LMXBs, a trend similar to that found in elliptical galaxies. On the other hand, the four most luminous GC LMXBs, with apparently super-Eddington luminosities for an accreting neutron star, are found in metal-poor GCs. We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-law indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC-LF at fainter luminosities down to 1035 erg s-1. The derived index rules out a faint-end slope flatter than 1.1 at a 2σ significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1037 erg s-1. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic active galactic nuclei (52 ± 11 [1σ]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of

  17. 40 CFR 49.128 - Rule for limiting particulate matter emissions from wood products industry sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... operation. PM10 emissions from wood particle dryers must not exceed a total of 0.4 pounds per 1000 square... emissions from wood products industry sources. 49.128 Section 49.128 Protection of Environment ENVIRONMENTAL... Region 10 § 49.128 Rule for limiting particulate matter emissions from wood products industry sources....

  18. 40 CFR 49.128 - Rule for limiting particulate matter emissions from wood products industry sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... operation. PM10 emissions from wood particle dryers must not exceed a total of 0.4 pounds per 1000 square... emissions from wood products industry sources. 49.128 Section 49.128 Protection of Environment ENVIRONMENTAL... Region 10 § 49.128 Rule for limiting particulate matter emissions from wood products industry sources....

  19. 40 CFR 49.128 - Rule for limiting particulate matter emissions from wood products industry sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... PM10 emissions from wood particle dryers must not exceed a total of 0.4 pounds per 1000 square feet of... emissions from wood products industry sources. 49.128 Section 49.128 Protection of Environment ENVIRONMENTAL... Rule for limiting particulate matter emissions from wood products industry sources. (a) What is...

  20. 77 FR 26476 - Standards of Performance for Greenhouse Gas Emissions for New Stationary Sources: Electric...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-04

    ... AGENCY 40 CFR Part 60 Standards of Performance for Greenhouse Gas Emissions for New Stationary Sources... proposed rule, ``Standards of Performance for Greenhouse Gas Emissions for New Stationary Sources: Electric... for the proposed Standards of Performance for Greenhouse Gas Emissions for New Stationary...

  1. 40 CFR 75.83 - Calculation of Hg mass emissions and heat input rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Calculation of Hg mass emissions and... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Hg Mass Emission Provisions § 75.83 Calculation of Hg mass emissions and heat input rate. The owner or operator shall calculate Hg mass...

  2. Sequential multi-nuclide emission rate estimation method based on gamma dose rate measurement for nuclear emergency management.

    PubMed

    Zhang, Xiaole; Raskob, Wolfgang; Landman, Claudia; Trybushnyi, Dmytro; Li, Yu

    2017-03-05

    In case of a nuclear accident, the source term is typically not known but extremely important for the assessment of the consequences to the affected population. Therefore the assessment of the potential source term is of uppermost importance for emergency response. A fully sequential method, derived from a regularized weighted least square problem, is proposed to reconstruct the emission and composition of a multiple-nuclide release using gamma dose rate measurement. The a priori nuclide ratios are incorporated into the background error covariance (BEC) matrix, which is dynamically augmented and sequentially updated. The negative estimations in the mathematical algorithm are suppressed by utilizing artificial zero-observations (with large uncertainties) to simultaneously update the state vector and BEC. The method is evaluated by twin experiments based on the JRodos system. The results indicate that the new method successfully reconstructs the emission and its uncertainties. Accurate a priori ratio accelerates the analysis process, which obtains satisfactory results with only limited number of measurements, otherwise it needs more measurements to generate reasonable estimations. The suppression of negative estimation effectively improves the performance, especially for the situation with poor a priori information, where it is more prone to the generation of negative values.

  3. Volatile organic compound emissions from unconventional natural gas production: Source signatures and air quality impacts

    NASA Astrophysics Data System (ADS)

    Swarthout, Robert F.

    Advances in horizontal drilling and hydraulic fracturing over the past two decades have allowed access to previously unrecoverable reservoirs of natural gas and led to an increase in natural gas production. Intensive unconventional natural gas extraction has led to concerns about impacts on air quality. Unconventional natural gas production has the potential to emit vast quantities of volatile organic compounds (VOCs) into the atmosphere. Many VOCs can be toxic, can produce ground-level ozone or secondary organic aerosols, and can impact climate. This dissertation presents the results of experiments designed to validate VOC measurement techniques, to quantify VOC emission rates from natural gas sources, to identify source signatures specific to natural gas emissions, and to quantify the impacts of these emissions on potential ozone formation and human health. Measurement campaigns were conducted in two natural gas production regions: the Denver-Julesburg Basin in northeast Colorado and the Marcellus Shale region surrounding Pittsburgh, Pennsylvania. An informal measurement intercomparison validated the canister sampling methodology used throughout this dissertation for the measurement of oxygenated VOCs. Mixing ratios of many VOCs measured during both campaigns were similar to or higher than those observed in polluted cities. Fluxes of natural gas-associated VOCs in Colorado ranged from 1.5-3 times industry estimates. Similar emission ratios relative to propane were observed for C2-C6 alkanes in both regions, and an isopentane:n-pentane ratio ≈1 was identified as a unique tracer for natural gas emissions. Source apportionment estimates indicated that natural gas emissions were responsible for the majority of C2-C8 alkanes observed in each region, but accounted for a small proportion of alkenes and aromatic compounds. Natural gas emissions in both regions accounted for approximately 20% of hydroxyl radical reactivity, which could hinder federal ozone standard

  4. Evaluation of PM 10 emission rates from paved and unpaved roads using tracer techniques

    NASA Astrophysics Data System (ADS)

    Claiborn, Candis; Mitra, Arundhati; Adams, Glenn; Bamesberger, Lee; Allwine, Gene; Kantamaneni, Ravi; Lamb, Brian; Westberg, Hal

    Spokane, WA, is a nonattainment area for airborne particulate matter smaller than 10μm (PM 10), so that a detailed emission inventory for PM 10 is needed to evaluate various control strategies. It is thought that emissions from paved and unpaved roads in Spokane contribute three-fourths of the anthropogenic PM 10 (neglecting wind-blown dust from agricultural areas). A study was conducted in the summer and fall of 1992 and again in the spring and summer of 1994 to measure PM 10 emission rates from paved and unpaved roads in Eastern Washington state using a novel tracer technique. A known amount of an inert tracer (SF 6) was released and concentrations of PM 10 and SF 6 downwind of the road, along with meteorological parameters and traffic volume, were measured. The results of the tracer experiments showed that within experimental uncertainties the PM 10 and the tracer gas disperse in the same manner, suggesting that the use of a tracer in a line source to simulate roadway PM 10 emissions can provide a tool for improving the existing emission inventories from roads. The emission factors obtained from two unpaved road experiments (136 g per vehicle per kilometer traveled, or g VKT -1, and 336 g VKT -1) were similar in magnitude to those predicted using currently accepted empirical algorithms. The factors determined from six paved road experiments were approximately 80% higher than that predicted using current formulae (6.7 ± 3.7 g VKT -1 compared to 3.7 g VKT -1) for two-lane roads with daily traffic less than 10,000 vehicles. For major highways (4 + lanes and traffic in excess of 10,000 vehicles per day) the emission factors obtained from the tracer experiments were, on average, 44% lower than those predicted using standard formulae (1.0 ± 0.5 g VKT -1 compared to 1.8 g VKT -1). The calculated emission factors for paved roads exhibited a wide range of variability, suggesting that in order to quantify PM 10 emission rates from paved roads, more investigation is

  5. Source limitation of carbon gas emissions in high-elevation mountain streams and lakes

    NASA Astrophysics Data System (ADS)

    Crawford, John T.; Dornblaser, Mark M.; Stanley, Emily H.; Clow, David W.; Striegl, Robert G.

    2015-05-01

    Inland waters are an important component of the global carbon cycle through transport, storage, and direct emissions of CO2 and CH4 to the atmosphere. Despite predictions of high physical gas exchange rates due to turbulent flows and ubiquitous supersaturation of CO2—and perhaps also CH4—patterns of gas emissions are essentially undocumented for high mountain ecosystems. Much like other headwater networks around the globe, we found that high-elevation streams in Rocky Mountain National Park, USA, were supersaturated with CO2 during the growing season and were net sources to the atmosphere. CO2 concentrations in lakes, on the other hand, tended to be less than atmospheric equilibrium during the open water season. CO2 and CH4 emissions from the aquatic conduit were relatively small compared to many parts of the globe. Irrespective of the physical template for high gas exchange (high k), we found evidence of CO2 source limitation to mountain streams during the growing season, which limits overall CO2 emissions. Our results suggest a reduced importance of aquatic ecosystems for carbon cycling in high-elevation landscapes having limited soil development and high CO2 consumption via mineral weathering.

  6. Source limitation of carbon gas emissions in high-elevation mountain streams and lakes

    USGS Publications Warehouse

    Crawford, John T.; Dornblaser, Mark M.; Stanley, Emily H.; Clow, David W.; Striegl, Robert G.

    2015-01-01

    Inland waters are an important component of the global carbon cycle through transport, storage, and direct emissions of CO2 and CH4 to the atmosphere. Despite predictions of high physical gas exchange rates due to turbulent flows and ubiquitous supersaturation of CO2—and perhaps also CH4—patterns of gas emissions are essentially undocumented for high mountain ecosystems. Much like other headwater networks around the globe, we found that high-elevation streams in Rocky Mountain National Park, USA, were supersaturated with CO2 during the growing season and were net sources to the atmosphere. CO2concentrations in lakes, on the other hand, tended to be less than atmospheric equilibrium during the open water season. CO2 and CH4 emissions from the aquatic conduit were relatively small compared to many parts of the globe. Irrespective of the physical template for high gas exchange (high k), we found evidence of CO2 source limitation to mountain streams during the growing season, which limits overall CO2emissions. Our results suggest a reduced importance of aquatic ecosystems for carbon cycling in high-elevation landscapes having limited soil development and high CO2 consumption via mineral weathering.

  7. Next Generation Emission Measurements for Fugitive, Area Source, and Fence Line Applications?

    EPA Science Inventory

    Next generation emissions measurements (NGEM) is an EPA term for the rapidly advancing field of air pollutant sensor technologies, data integration concepts, and associated geospatial modeling strategies for source emissions measurements. Ranging from low coat sensors to satelli...

  8. Emissions from Combustion of Open Area Sources: Prescribed Forest and Agricultural Burns

    EPA Science Inventory

    Emissions from wildfires and prescribed forest and agricultural burns generate a variety of emissions that can cause adverse health effects for humans, contribute to climate change, and decrease visibility. Only limited pollutant data are available for these sources, particularly...

  9. Contribution of Changing Sources and Sinks to the Growth Rate of Atmospheric Methane Concentrations for the Last Two Decades

    NASA Technical Reports Server (NTRS)

    Matthews, Elaine; Walter, B.; Bogner, J.; Sarma, D.; Portney, B.; Hansen, James (Technical Monitor)

    2000-01-01

    In situ measurements of atmospheric methane concentrations begun in the early 1980s show decadal trends, as well as large interannual variations, in growth rate. Recent research indicates that while wetlands can explain several of the large growth anomalies for individual years, the decadal trend may be the combined effect of increasing sinks, due to increases in tropospheric OH, and stabilizing sources. We discuss new 20-year histories of annual, global source strengths for all major methane sources, i.e., natural wetlands, rice cultivation, ruminant animals, landfills, fossil fuels, and biomass burning, and present estimates of the temporal pattern of the sink required to reconcile these sources and atmospheric concentrations over the time period. Analysis of the individual emission sources, together with model-derived estimates of the OH sink strength, indicates that the growth rate of atmospheric methane observed over the last 20 years can only be explained by a combination of changes in source emissions and an increasing tropospheric sink.

  10. COMBINING RATE-BASED AND CAP-AND-TRADE EMISSIONS POLICIES. (R828628)

    EPA Science Inventory

    Rate-based emissions policies (like tradable performance standards, TPS) fix average emissions intensity, while cap-and-trade (CAT) policies fix total emissions. This paper shows that unfettered trade between rate-based and cap-and-trade programs always raises combined emissio...

  11. Exhaust Emission Rates for Heavy-Duty Onroad Vehicles in the Next Version of MOVES

    EPA Science Inventory

    Derivation of the exhaust and crankcase emission rates for HC, CO, NOx, and PM emissions from medium and heavy-duty diesel, gasoline, and compressed natural gas vehicles. Including updates for emission rates for 2007 and later model year diesel vehicles

  12. Characterization of helium/argon working gas systems in a radiofrequency glow discharge atomic emission source. Part I: Optical emission, sputtering and electrical characteristics

    NASA Astrophysics Data System (ADS)

    Christopher, Steven J.; Hartenstein, Matthew L.; Marcus, R. Kenneth; Belkin, Mikhail; Caruso, Joseph A.

    1998-08-01

    Studies are performed to determine the influence of discharge gas composition (helium/argon working gas mixtures) on the analyte emission signal intensities, sputtering rates, and DC-bias characteristics of an analytical radiofrequency glow discharge atomic emission spectroscopy (RF-GD-AES) source. As the partial pressure of He is increased from 0 to 15 torr, increased emission intensity is observed for a range of bulk and trace elements in NIST 1250 SRM (low alloy steel), regardless of the base pressure of Ar in the source (5 and 9 torr). In contrast to increases in analyte emission intensity of up to 300%, counterindicative decreases in the sputtering rates on the order of about 30-50% are observed. The magnitude of these effects depends on both the partial pressure of helium introduced to the source and the total pressure of the He and Ar gases. Use of relative emission yield (REY) to normalize changes in emission intensity to sputtering rates indicates that excitation efficiencies increase under these conditions. Increases in average electron energy and temperature appear to control this response. Decreases in both analyte emission intensities and sputter rates occur with increasing He partial pressure when the total pressure in the cell remains fixed (11 torr in these studies). Emission yields for the fixed pressure, mixed gas plasmas decrease as the partial pressure of He (He/Ar ratio) in the RF-GD source increases. In this case, decreases in electron number densities appear to dictate the lower REYs. Measurement of DC-bias values at the sample surface provide understanding with respect to the observed changes in sputtering rates as well as suggest the origins of changes in plasma electron energetics. Use of a diamond stylus profilometer provides both the quantitative sputter rate information as well as qualitative insights into the use of mixed gas plasmas for enhanced depth profiling capabilities. The analyte emission characteristics of these mixed gas

  13. 40 CFR 63.1316 - PET and polystyrene affected sources-emissions control provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutant Emissions: Group IV Polymers.... Compliance can be based on either organic HAP or TOC. (1) The owner or operator of an affected source...) through (b)(1)(iv) of this section. (i) The owner or operator of an existing affected source with...

  14. HVAC SYSTEMS AS EMISSION SOURCES AFFECTING INDOOR AIR QUALITY: A CRITICAL REVIEW

    EPA Science Inventory

    The paper discusses results of an evaluation of literature on heating, ventilating, and air-conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). The various literature sources and methods for characterizing HVAC emission sources are re...

  15. EMISSION FACTORS FOR IRON AND STEEL SOURCES: CRITERIA AND TOXIC POLLUTANTS

    EPA Science Inventory

    The report provides a comprehensive set of emission factors for sources of both criteria and toxic air pollutants in integrated iron and steel plants and specialty electric arc shops (minimills). Emission factors are identified for process sources, and process and open source fug...

  16. A smart repetitive-rate wideband high power microwave source

    SciTech Connect

    Li, Wei; Zhang, Jun; Qian, Bao-liang; Yang, Han-wu; Zhang, Zi-cheng

    2016-01-15

    A smart repetitive-rate wideband High Power Microwave (HPM) source based on the A6 Magnetron with Diffraction Output is described in this paper. The length of the HPM source is 30 cm and its weight is 35 kg. Computer simulations show that the source can produce microwave with central frequency of 1.91 GHz and bandwidth of about 11%. Experimental measurements show that the output microwave power from the source reaches in maximum 110 MW when the input electric power from the pulsed driver is ∼500 MW, which gives the power conversion efficiency 22%. Central frequency of the output HPM in the experiment is 1.94 GHz with the bandwidth ranging from 1.82 GHz to 2.02 GHz. The jitter of the output HPM power is lower than 3 dB when the source operates in the repetition mode with 50 Hz rate.

  17. A Global Catalogue of Large SO2 Sources and Emissions Derived from the Ozone Monitoring Instrument

    NASA Technical Reports Server (NTRS)

    Fioletov, Vitali E.; McLinden, Chris A.; Krotkov, Nickolay; Li, Can; Joiner, Joanna; Theys, Nicolas; Carn, Simon; Moran, Mike D.

    2016-01-01

    Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr(exp -1) to more than 4000 kt yr(exp -1) of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smelters (53); and sources related to the oil and gas industry (65). The sources were identified using different methods, including through OMI measurements themselves applied to a new emission detection algorithm, and their evolution during the 2005- 2014 period was traced by estimating annual emissions from each source. For volcanic sources, the study focused on continuous degassing, and emissions from explosive eruptions were excluded. Emissions from degassing volcanic sources were measured, many for the first time, and collectively they account for about 30% of total SO2 emissions estimated from OMI measurements, but that fraction has increased in recent years given that cumulative global emissions from power plants and smelters are declining while emissions from oil and gas industry remained nearly constant. Anthropogenic emissions from the USA declined by 80% over the 2005-2014 period as did emissions from western and central Europe, whereas emissions from India nearly doubled, and emissions from other large SO2-emitting regions (South Africa, Russia, Mexico, and the Middle East) remained fairly constant. In total, OMI-based estimates account for about a half of total reported anthropogenic SO2 emissions; the remaining half is likely related to sources emitting less than 30 kt yr(exp -1) and not detected by OMI.

  18. A global catalogue of large SO2 sources and emissions derived from the Ozone Monitoring Instrument

    NASA Astrophysics Data System (ADS)

    Fioletov, Vitali E.; McLinden, Chris A.; Krotkov, Nickolay; Li, Can; Joiner, Joanna; Theys, Nicolas; Carn, Simon; Moran, Mike D.

    2016-09-01

    Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor processed with the new principal component analysis (PCA) algorithm were used to detect large point emission sources or clusters of sources. The total of 491 continuously emitting point sources releasing from about 30 kt yr-1 to more than 4000 kt yr-1 of SO2 per year have been identified and grouped by country and by primary source origin: volcanoes (76 sources); power plants (297); smelters (53); and sources related to the oil and gas industry (65). The sources were identified using different methods, including through OMI measurements themselves applied to a new emission detection algorithm, and their evolution during the 2005-2014 period was traced by estimating annual emissions from each source. For volcanic sources, the study focused on continuous degassing, and emissions from explosive eruptions were excluded. Emissions from degassing volcanic sources were measured, many for the first time, and collectively they account for about 30 % of total SO2 emissions estimated from OMI measurements, but that fraction has increased in recent years given that cumulative global emissions from power plants and smelters are declining while emissions from oil and gas industry remained nearly constant. Anthropogenic emissions from the USA declined by 80 % over the 2005-2014 period as did emissions from western and central Europe, whereas emissions from India nearly doubled, and emissions from other large SO2-emitting regions (South Africa, Russia, Mexico, and the Middle East) remained fairly constant. In total, OMI-based estimates account for about a half of total reported anthropogenic SO2 emissions; the remaining half is likely related to sources emitting less than 30 kt yr-1 and not detected by OMI.

  19. VOLATILE ORGANIC COMPOUND EMISSION RATES FROM MIXED DECIDUOUS AND CONIFEROUS FORESTS IN NORTHERN WISCONSIN, USA

    EPA Science Inventory

    Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regio...

  20. Emission of volatile organic compounds from silage: Compounds, sources, and implications

    NASA Astrophysics Data System (ADS)

    Hafner, Sasha D.; Howard, Cody; Muck, Richard E.; Franco, Roberta B.; Montes, Felipe; Green, Peter G.; Mitloehner, Frank; Trabue, Steven L.; Rotz, C. Alan

    2013-10-01

    Silage, fermented cattle feed, has recently been identified as a significant source of volatile organic compounds (VOCs) to the atmosphere. A small number of studies have measured VOC emission from silage, but not enough is known about the processes involved to accurately quantify emission rates and identify practices that could reduce emissions. Through a literature review, we have focused on identifying the most important compounds emitted from corn silage (the most common type of silage in the US) and the sources of these compounds by quantifying their production and emission potential in silage and describing production pathways. We reviewed measurements of VOC emission from silage and assessed the importance of individual silage VOCs through a quantitative analysis of VOC concentrations within silage. Measurements of VOC emission from silage and VOCs present within silage indicated that alcohols generally make the largest contribution to emission from corn silage, in terms of mass emitted and potential ozone formation. Ethanol is the dominant alcohol in corn silage; excluding acids, it makes up more than half of the mean mass of VOCs present. Acids, primarily acetic acid, may be important when emission is high and all VOCs are nearly depleted by emission. Aldehydes and esters, which are more volatile than acids and alcohols, are important when exposure is short, limiting emission of more abundant but less volatile compounds. Variability in silage VOC concentrations is very high; for most alcohols and acids, tolerance intervals indicate that 25% of silages have concentrations a factor of two away from median values, and possibly much further. This observation suggests that management practices can significantly influence VOC concentrations. Variability also makes prediction of emissions difficult. The most important acids, alcohols, and aldehydes present in silage are probably produced by bacteria (and, in the case of ethanol, yeasts) during fermentation and

  1. The nuclear region of low luminosity flat radio spectrum sources. II. Emission-line spectra

    NASA Astrophysics Data System (ADS)

    Gonçalves, A. C.; Serote Roos, M.

    2004-01-01

    We report on the spectroscopic study of 19 low luminosity Flat Radio Spectrum (LL FRS) sources selected from Marchã's et al. (\\cite{March96}) 200 mJy sample. In the optical, these objects are mainly dominated by the host galaxy starlight. After correcting the data for this effect, we obtain a new set of spectra clearly displaying weak emission lines; such features carry valuable information concerning the excitation mechanisms at work in the nuclear regions of LL FRS sources. We have used a special routine to model the spectra and assess the intensities and velocities of the emission lines; we have analyzed the results in terms of diagnostic diagrams. Our analysis shows that 79% of the studied objects harbour a Low Ionization Nuclear Emission-line Region (or LINER) whose contribution was swamped by the host galaxy starlight. The remaining objects display a higher ionization spectrum, more typical of Seyferts; due to the poor quality of the spectra, it was not possible to identify any possible large Balmer components. The fact that we observe a LINER-type spectrum in LL FRS sources supports the idea that some of these objects could be undergoing an ADAF phase; in addition, such a low ionization emission-line spectrum is in agreement with the black hole mass values and sub-Eddington accretion rates published for some FRS sources. Based on observations collected at the Multiple Mirror Telescope on Mt. Hopkins. Full Fig. 1 is only available in electronic form at http://www.edpsciences.org

  2. A waveguide electron cyclotron resonance source of X-ray emission for low-dose introscopy

    NASA Astrophysics Data System (ADS)

    Sergeichev, K. F.; Ionidi, V. Yu.; Karfidov, D. M.; Lukina, N. A.

    2013-12-01

    It is shown that a "point" target in a conventional evacuated waveguide in the magnetic field of a mirror trap formed by two disk magnets axially magnetized in the direction perpendicular to the electric field vector represents a source of X-ray bremsstrahlung of electrons accelerated in an ECR discharge with a broad range of photon energies up to 0.8 MeV. The dosage rate of the source is ˜1 R/h. The source fed from a conventional microwave oven has small dimensions and a low weight. It is easy-to-use and is suitable as a laboratory tool, in particular, in radiobiology and introscopy. After passing through the object, X-ray emission is recorded by a digital camera with the help of a highly sensitive X-ray fluorescent screen, which converts it into an optical image.

  3. Impact of routine episodic emissions on the expected frequency distribution of emissions from oil and gas production sources.

    NASA Astrophysics Data System (ADS)

    Smith, N.; Blewitt, D.; Hebert, L. B.

    2015-12-01

    In coordination with oil and gas operators, we developed a high resolution (< 1 min) simulation of temporal variability in well-pad oil and gas emissions over a year. We include routine emissions from condensate tanks, dehydrators, pneumatic devices, fugitive leaks and liquids unloading. We explore the variability in natural gas emissions from these individual well-pad sources, and find that routine short-term episodic emissions such as tank flashing and liquids unloading result in the appearance of a skewed, or 'fat-tail' distribution of emissions, from an individual well-pad over time. Additionally, we explore the expected variability in emissions from multiple wells with different raw gas composition, gas/liquids production volumes and control equipment. Differences in well-level composition, production volume and control equipment translate into differences in well-level emissions leading to a fat-tail distribution of emissions in the absence of operational upsets. Our results have several implications for recent studies focusing on emissions from oil and gas sources. Time scale of emission estimates are important and have important policy implications. Fat tail distributions may not be entirely driven by avoidable mechanical failures, and are expected to occur under routine operational conditions from short-duration emissions (e.g., tank flashing, liquid unloading). An understanding of the expected distribution of emissions for a particular population of wells is necessary to evaluate whether the observed distribution is more skewed than expected. Temporal variability in well-pad emissions make comparisons to annual average emissions inventories difficult and may complicate the interpretation of long-term ambient fenceline monitoring data. Sophisticated change detection algorithms will be necessary to identify when true operational upsets occur versus routine short-term emissions.

  4. Estimates of solid waste disposal rates and reduction targets for landfill gas emissions

    NASA Astrophysics Data System (ADS)

    Powell, Jon T.; Townsend, Timothy G.; Zimmerman, Julie B.

    2016-02-01

    Landfill disposal of municipal solid waste represents one of the largest anthropogenic global methane emission sources, and recent policy approaches have targeted significant reductions of these emissions to combat climate change in the US (ref. ). The efficacy of active gas collection systems in the US was examined by analysing performance data, including fire occurrence, from more than 850 landfills. A generalized linear model showed that the operating status of a landfill--open and actively receiving waste or closed--was the most significant predictor of collection system performance. Gas collection systems at closed landfills were statistically significantly more efficient (p < 0.001) and on average 17 percentage points more efficient than those at open landfills, but open landfills were found to represent 91% of all landfill methane emissions. These results demonstrate the clear need to target open landfills to achieve significant near-term methane emission reductions. This observation is underscored by landfill disposal rates in the US significantly exceeding previously reported national estimates, with this study reporting 262 million tonnes in the year 2012 compared with 122 million tonnes in 2012 as estimated by the US Environmental Protection Agency.

  5. Source fingerprint monitoring of air pollutants from petrochemical industry and the determination of their annual emission flux using open path Fourier transform infrared spectroscopy

    SciTech Connect

    Yih-Shiaw Huang; Shih-Yi Chang; Tai-Ly Tso

    1996-12-31

    Toxic air pollutants were investigated in several petrochemical industrial park in Taiwan using a movable open-path Fourier-transform infrared spectroscopy (FTIR). The results show the qualitative and quantitative analysis of emission gases from plants, and also provide the emission rates of various compounds. More than twenty compounds under usual operation were found from these industrial park. The concentration variation with time could be correlated exactly with the distances from the emission source along the wind direction. This means that by changing the measuring points the source of emission could be unambiguously identified. The point, area and line source (PAL) plume dispersion model has been applied to estimate the emission rate of either a point or an area source. The local atmospheric stability was determined by releasing an SF{sub 6} tracer. The origin of errors came mainly from the uncertainty of the source configuration and the variation of the meteorological condition. Through continuous measurement using a portable open-path Fourier transform infrared (POP-FTIR) spectrometer, the maximum value of the emission rate and the annual amount of emission could be derived. The emission rate of the measured toxic gases was derived by the model technique, and the results show that the emission amount is on the order of ten to hundred tons per year.

  6. Global sources of non-CO2 greenhouse gas emissions: regional trends, uncertainties and options for emission reductions

    NASA Astrophysics Data System (ADS)

    Olivier, J. G.; van Aardenne, J. A.; Peters, J. A.

    2005-05-01

    An overview will be presented of sources and trends of global emissions of direct non-CO2 greenhouse gases CH4, N2O and the fluorinated gases HFCs, PFCs and SF6, which are addressed in the Kyoto protocol. Special attention will be given to regional source trends, estimated uncertainties and most recent global emission trends. In addition, the most significant options for emission reductions will be discussed in view of medium term emission scenarios that were meant to illustrate future trends without the effects climate policy. For estimating the recent global emission trends a special approach was used to compile fast annual updates of the EDGAR global emission inventories, based on the more detailed previous version. We present an overview of the approaches used for this `Fast Track' for the different source sectors. Results are presented for 1995-2002 for various anthropogenic sources at regional scales including an estimate of the accuracies achieved. A similar overview will be provided for the emissions of the ozone precursors NOx, CO and NMVOC and of black carbon. Tropospheric ozone and black carbon are both greenhouse gases, which are not considered in the Kyoto protocol, but in industrialised countries the emissions that cause them are often part of environmental policy on local and regional air quality.

  7. Component Failure Rate Data Sources for Probabilistic Safety and Reliability

    SciTech Connect

    L. C. Cadwallader; S. A. Eide

    2010-09-01

    Probabilistic safety methods are being used in several industries, including chemical, manufacturing, and energy. When performing reliability studies or using probabilistic safety approaches, a basic need arises for input data on failure rates of the mechanical, electrical, instrumentation and control, and other components that comprise the engineering systems in the facility. Some companies have many types of data stored and can retrieve these in-house data for such uses. Other companies hire consultants to perform safety assessments; the consulting firms often use their own data bases. For those analysts who do not have either of those options available, this paper presents some data sources that are retrievable from the literature. These data sources have been evaluated with a basic rating of usefulness for analysis work, and each has a description of what data can be found in the citation that can be used to support assessments in industry. The accessibility of data documents via the internet is also described.

  8. Evaluation of backward Lagrangian stochastic (bLS) model to estimate gas emissions from complex sources based on numerical simulations

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Liu, Wenqing; Zhang, Tianshu; Ren, Manyan

    2013-03-01

    The focus of the paper is application of an inverse-dispersion technique based on a backward Lagrangian stochastic (bLS) model in order to calculate gas-emission rates from industrial complexes. While the bLS technique is attractive for these types of sources, the bLS calculation must assume a spatial configuration for the source. Therefore, results are presented herein of numerical simulations designed to study the sensitivity of emissions calculations to the assumption of source configuration for complex industrial sources. We discuss how measurement fetch, concentration sensor height, and optical path length influence the accuracy of emission estimation. Through simulations, we identify an improved sensor configuration in order to reduce emission-calculation errors caused by an incorrect source-configuration assumption. It is concluded that, with respect to our defined source, the optimal measurement fetch may be between 200 m and 300 m; also, the ideal measurement height is probably between 2.0 m and 2.5 m. With choices within these two ranges, a path length of about 200 m is adequate, and greater path lengths, above 200 m, result in no substantial improvement in emission calculations.

  9. Film dosimetry calibration method for pulsed-dose-rate brachytherapy with an 192Ir source.

    PubMed

    Schwob, Nathan; Orion, Itzhak

    2007-05-01

    192Ir sources have been widely used in clinical brachytherapy. An important challenge is to perform dosimetric measurements close to the source despite the steep dose gradient. The common, inexpensive silver halide film is a classic two-dimensional integrator dosimeter and would be an attractive solution for these dose measurements. The main disadvantage of film dosimetry is the film response to the low-energy photon. Since the photon energy spectrum is known to vary with depth, the sensitometric curves are expected to be dependent on depth. The purpose of this study is to suggest a correction method for silver halide film dosimetry that overcomes the response changes at different depths. Sensitometric curves have been obtained at different depths with verification film near a 1 Ci 192Ir pulsed-dose-rate source. The depth dependence of the film response was observed and a correction function was established. The suitability of the method was tested through measurement of the radial dose profile and radial dose function. The results were compared to Monte Carlo-simulated values according to the TG43 formalism. Monte Carlo simulations were performed separately for the beta and gamma source emissions, using the EGS4 code system, including the low-energy photon and electron transport optimization procedures. The beta source emission simulation showed that the beta dose contribution could be neglected and therefore the film-depth dependence could not be attributed to this part of the source radioactivity. The gamma source emission simulations included photon-spectra collection at several depths. The results showed a depth-dependent softening of the photon spectrum that can explain the film-energy dependence.

  10. Sources of variability in distortion product otoacoustic emissions

    PubMed Central

    Garner, Cassie A.; Neely, Stephen T.; Gorga, Michael P.

    2008-01-01

    The goal of this study was to determine the extent to which the variability seen in distortion product otoacoustic emissions (DPOAEs), among ears with normal hearing, could be accounted for. Several factors were selected for investigation, including behavioral threshold, differences in middle-ear transmission characteristics either in the forward or the reverse direction, and differences in contributions from the distortion and reflection sources. These variables were assessed after optimizing stimulus parameters for individual ears at each frequency. A multiple-linear regression was performed to identify whether the selected variables, either individually or in combination, explained significant portions of variability in DPOAE responses. Behavioral threshold at the f2 frequency and behavioral threshold squared at that same frequency explained the largest amount of variability in DPOAE level, compared to the other variables. The combined model explained a small, but significant, amount of variance in DPOAE level at five frequencies. A large amount of residual variability remained, even at frequencies where the model accounted for significant amounts of variance. PMID:18681596

  11. Modelling the NO emissions from wildfires at the source level

    NASA Astrophysics Data System (ADS)

    Pérez-Ramirez, Y.; Santoni, P.-A.; Darabiha, N.

    2014-05-01

    There is a growing interest to characterize fire plumes in order to control air quality during wildfire episodes and to estimate the carbon and ozone balance of fire emissions. A numerical approach has been used to study the mechanisms of NO formation at the source level in wildfires given that NO plays an important role in the formation of ground-level ozone. The major reaction mechanisms involved in NO chemistry have been identified using reaction path analysis. Accordingly, a two-step global kinetic scheme in the gas phase has been proposed herein to account for the volatile fuel-bound nitrogen (fuel-N) conversion to NO, considering that the volatile fraction of fuel-N is released as NH3. Data from simulations using the perfectly stirred reactor (PSR) code from CHEMKIN-II package with a detailed kinetic mechanism (GDF-Kin® 3.0) have been used to calibrate and evaluate the global model under typical wildfire conditions in terms of the composition of the degradation gases of vegetation, the equivalence ratio, the range of temperatures and the residence time.

  12. Nine years of global hydrocarbon emissions based on source inversion of OMI formaldehyde observations

    NASA Astrophysics Data System (ADS)

    Bauwens, Maite; Stavrakou, Trissevgeni; Müller, Jean-François; De Smedt, Isabelle; Van Roozendael, Michel; van der Werf, Guido R.; Wiedinmyer, Christine; Kaiser, Johannes W.; Sindelarova, Katerina; Guenther, Alex

    2016-08-01

    are suggested in Indochina and during the 2007 fires in southern Europe. Moreover, changes in fire seasonal patterns are suggested; e.g., the seasonal amplitude is reduced over southeast Asia. In Africa, the inversion indicates increased fluxes due to agricultural fires and decreased maxima when natural fires are dominant. The top-down fire emissions are much better correlated with MODIS fire counts than the a priori inventory in regions with small and agricultural fires, indicating that the OMI-based inversion is well-suited to assess the associated emissions. Regarding biogenic sources, significant reductions in isoprene fluxes are inferred in tropical ecosystems (30-40 %), suggesting overestimated basal emission rates in those areas in the bottom-up inventory, whereas strongly positive isoprene emission updates are derived over semiarid and desert areas, especially in southern Africa and Australia. This finding suggests that the parameterization of the soil moisture stress used in MEGAN greatly exaggerates the flux reduction due to drought in those regions. The isoprene emission trends over 2005-2013 are often enhanced after optimization, with positive top-down trends in Siberia (4.2 % year-1) and eastern Europe (3.9 % year-1), likely reflecting forest expansion and warming temperatures, and negative trends in Amazonia (-2.1 % year-1), south China (-1 % year-1), the United States (-3.7 % year-1), and western Europe (-3.3 % year-1), which are generally corroborated by independent studies, yet their interpretation warrants further investigation.

  13. Quantifying Spatial and Temporal Variability of Methane Emissions from a Complex Area Source: Case Study of a Central Indiana Landfill

    NASA Astrophysics Data System (ADS)

    Cambaliza, M. O. L.; Bogner, J. E.; Green, R. B.; Shepson, P. B.; Thoma, E. D.; Foster-wittig, T. A.; Spokas, K.

    2014-12-01

    Atmospheric methane is a powerful greenhouse gas that is responsible for about 17% of the total direct radiative forcing from long-lived greenhouse gases (IPCC 2013). While the global emission of methane is relatively well quantified, the temporal and spatial variability of methane emissions from individual area or point sources are still poorly understood. Using 4 field methods (aircraft-based mass balance, tracer correlation, vertical radial plume mapping, and static chambers) and a new field-validated process-based model (California Landfill Methane Inventory Model, CALMIM 5.4), we investigated both the total emissions from a central Indiana landfill as well as the partitioned emissions inclusive of methanotrophic oxidation for the various cover soils. This landfill is an upwind source for the city of Indianapolis, so the resolution of m2 to km2 scale emissions, as well as understanding the temporal variability for this complex area source, contributes to improved regional inventory calculations. Emissions for the site as a whole were measured using both an aircraft-based mass balance approach as well as a ground-based tracer correlation method, permitting direct comparison of the strengths, limitations, and uncertainties of these two approaches. Because US landfills are highly-engineered and composed of daily, intermediate, and final cover areas with differing thicknesses, composition, and implementation of gas recovery, we also expected different emission signatures and strengths from the various cover areas. Thus we also deployed static chambers and vertical radial plume mapping to quantify the spatial variability of emissions from the thinner daily and intermediate cover areas. Understanding the daily, seasonal and annual emission rates from a landfill is not trivial, and usually requires a combination of measurement and modeling approaches. Thus, our unique data set provides an opportunity to gain an improved understanding of the emissions from a complex

  14. Particulate metals and organic compounds from electronic and tobacco-containing cigarettes: comparison of emission rates and secondhand exposure.

    PubMed

    Saffari, Arian; Daher, Nancy; Ruprecht, Ario; De Marco, Cinzia; Pozzi, Paolo; Boffi, Roberto; Hamad, Samera H; Shafer, Martin M; Schauer, James J; Westerdahl, Dane; Sioutas, Constantinos

    2014-01-01

    In recent years, electronic cigarettes have gained increasing popularity as alternatives to normal (tobacco-containing) cigarettes. In the present study, particles generated by e-cigarettes and normal cigarettes have been analyzed and the degree of exposure to different chemical agents and their emission rates were quantified. Despite the 10-fold decrease in the total exposure to particulate elements in e-cigarettes compared to normal cigarettes, specific metals (e.g. Ni and Ag) still displayed a higher emission rate from e-cigarettes. Further analysis indicated that the contribution of e-liquid to the emission of these metals is rather minimal, implying that they likely originate from other components of the e-cigarette device or other indoor sources. Organic species had lower emission rates during e-cigarette consumption compared to normal cigarettes. Of particular note was the non-detectable emission of polycyclic aromatic hydrocarbons (PAHs) from e-cigarettes, while substantial emission of these species was observed from normal cigarettes. Overall, with the exception of Ni, Zn, and Ag, the consumption of e-cigarettes resulted in a remarkable decrease in secondhand exposure to all metals and organic compounds. Implementing quality control protocols on the manufacture of e-cigarettes would further minimize the emission of metals from these devices and improve their safety and associated health effects.

  15. Opacity meter for monitoring exhaust emissions from non-stationary sources

    DOEpatents

    Dec, John Edward

    2000-01-01

    Method and apparatus for determining the opacity of exhaust plumes from moving emissions sources. In operation, a light source is activated at a time prior to the arrival of a diesel locomotive at a measurement point, by means of a track trigger switch or the Automatic Equipment Identification system, such that the opacity measurement is synchronized with the passage of an exhaust plume past the measurement point. A beam of light from the light source passes through the exhaust plume of the locomotive and is detected by a suitable detector, preferably a high-rate photodiode. The light beam is well-collimated and is preferably monochromatic, permitting the use of a narrowband pass filter to discriminate against background light. In order to span a double railroad track and provide a beam which is substantially stronger than background, the light source, preferably a diode laser, must provide a locally intense beam. A high intensity light source is also desirable in order to increase accuracy at the high sampling rates required. Also included is a computer control system useful for data acquisition, manipulation, storage and transmission of opacity data and the identification of the associated diesel engine to a central data collection center.

  16. 75 FR 32682 - National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ..., Commercial, and Institutional Boilers and Process Heaters; National Emission Standards for Hazardous Air Pollutants for Area Sources: Industrial, Commercial, and Institutional Boilers; Standards of Performance for... the following source categories: Industrial, Commercial, and Institutional Boilers and Process...

  17. Local to regional emission sources affecting mercury fluxes to New York lakes

    NASA Astrophysics Data System (ADS)

    Bookman, Revital; Driscoll, Charles T.; Engstrom, Daniel R.; Effler, Steven W.

    Lake-sediment records across the Northern Hemisphere show increases in atmospheric deposition of anthropogenic mercury (Hg) over the last 150 years. Most of the previous studies have examined remote lakes affected by the global atmospheric Hg reservoir. In this study, we present Hg flux records from lakes in an urban/suburban setting of central New York affected also by local and regional emissions. Sediment cores were collected from the Otisco and Skaneateles lakes from the Finger Lakes region, Cross Lake, a hypereutrophic lake on the Seneca River, and Glacial Lake, a small seepage lake with a watershed that corresponds with the lake area. Sediment accumulation rates and dates were established by 210Pb. The pre-anthropogenic regional atmospheric Hg flux was estimated to be 3.0 μg m -2 yr -1 from Glacial Lake, which receives exclusively direct atmospheric deposition. Mercury fluxes peaked during 1971-2001, and were 3 to more than 30 times greater than pre-industrial deposition. Land use change and urbanization in the Otisco and Cross watersheds during the last century likely enhanced sediment loads and Hg fluxes to the lakes. Skaneateles and Glacial lakes have low sediment accumulation rates, and thus are excellent indicators for atmospheric Hg deposition. In these lakes, we found strong correlations with emission records for the Great Lakes region that markedly increased in the early 1900s, and peaked during WWII and in the early 1970s. Declines in modern Hg fluxes are generally evident in the core records. However, the decrease in sediment Hg flux at Glacial Lake was interrupted and has increased since the early 1990s probably due to the operation of new local emission sources. Assuming the global Hg reservoir tripled since the pre-industrial period, the contribution of local and regional emission sources to central New York lakes was estimated to about 80% of the total atmospheric Hg deposition.

  18. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    NASA Astrophysics Data System (ADS)

    Pirrone, N.; Cinnirella, S.; Feng, X.; Finkelman, R. B.; Friedli, H. R.; Leaner, J.; Mason, R.; Mukherjee, A. B.; Stracher, G. B.; Streets, D. G.; Telmer, K.

    2010-07-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr-1), artisanal small scale gold mining (400 Mg yr-1), non-ferrous metals manufacturing (310 Mg yr-1), cement production (236 Mg yr-1), waste disposal (187 Mg yr-1) and caustic soda production (163 Mg yr-1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions + re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  19. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    NASA Astrophysics Data System (ADS)

    Pirrone, N.; Cinnirella, S.; Feng, X.; Finkelman, R. B.; Friedli, H. R.; Leaner, J.; Mason, R.; Mukherjee, A. B.; Stracher, G. B.; Streets, D. G.; Telmer, K.

    2010-02-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr-1), artisanal small scale gold mining (400 Mg yr-1), non-ferrous metals manufacturing (310 Mg yr-1), cement production (236 Mg yr-1), waste disposal (187 Mg yr-1) and caustic soda production (163 Mg yr-1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions+re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  20. Historic emissions from deforestation and forest degradation in Mato Grosso, Brazil: 1) source data uncertainties

    PubMed Central

    2011-01-01

    Background Historic carbon emissions are an important foundation for proposed efforts to Reduce Emissions from Deforestation and forest Degradation and enhance forest carbon stocks through conservation and sustainable forest management (REDD+). The level of uncertainty in historic carbon emissions estimates is also critical for REDD+, since high uncertainties could limit climate benefits from credited mitigation actions. Here, we analyzed source data uncertainties based on the range of available deforestation, forest degradation, and forest carbon stock estimates for the Brazilian state of Mato Grosso during 1990-2008. Results Deforestation estimates showed good agreement for multi-year periods of increasing and decreasing deforestation during the study period. However, annual deforestation rates differed by > 20% in more than half of the years between 1997-2008, even for products based on similar input data. Tier 2 estimates of average forest carbon stocks varied between 99-192 Mg C ha-1, with greatest differences in northwest Mato Grosso. Carbon stocks in deforested areas increased over the study period, yet this increasing trend in deforested biomass was smaller than the difference among carbon stock datasets for these areas. Conclusions Estimates of source data uncertainties are essential for REDD+. Patterns of spatial and temporal disagreement among available data products provide a roadmap for future efforts to reduce source data uncertainties for estimates of historic forest carbon emissions. Specifically, regions with large discrepancies in available estimates of both deforestation and forest carbon stocks are priority areas for evaluating and improving existing estimates. Full carbon accounting for REDD+ will also require filling data gaps, including forest degradation and secondary forest, with annual data on all forest transitions. PMID:22208947

  1. Soil carbon dioxide emissions from the Mojave desert: Isotopic evidence for a carbonate source

    NASA Astrophysics Data System (ADS)

    Soper, Fiona M.; McCalley, Carmody K.; Sparks, Kimberlee; Sparks, Jed P.

    2017-01-01

    Arid soils represent a substantial carbonate pool and may participate in surface-atmosphere CO2 exchange via a diel cycle of carbonate dissolution and exsolution. We used a Keeling plot approach to determine the substrate δ13C of CO2 emitted from carbonate-dominated soils in the Mojave desert and found evidence for a nonrespiratory source that increased with surface temperature. In dry soils at 25-30°C, the CO2 substrate had δ13C values of -19.4 ± 4.2‰, indicative of respiration of organic material (soil organic matter = -23.1 ± 0.8‰). CO2 flux increased with temperature; maximum fluxes occurred above 60°C, where δ13CO2 substrate (-7.2‰ ± 2.8‰) approached soil carbonate values (0.2 ± 0.2‰). In wet soils, CO2 emissions were not temperature dependent, and δ13CO2 substrate was lower in vegetated soils with higher flux rates, higher organic C content, and potential root respiration. These data provide the first direct evidence of CO2 emissions from alkaline desert soils derived from an abiotic source and that diurnal emission patterns are strongly driven by surface temperature.

  2. Methane emissions in the US and Canada: contributions of various source sectors and evolution of emissions over time

    NASA Astrophysics Data System (ADS)

    Miller, S. M.; Michalak, A. M.; Wofsy, S. C.; Andrews, A. E.; Biraud, S.; Dlugokencky, E. J.; Fischer, M. L.; Janssens-Maenhout, G.; Kort, E. A.; Miller, B. R.; Miller, J. B.; Montzka, S. A.; Worthy, D. E. J.

    2014-12-01

    In this presentation, we quantify several aspects of methane emissions in the US and Canada using concentration data collected in the atmosphere. First, how much methane in total is emitted from the US and Canada? Second, how much methane is emitted from each individual source across these countries? Third, and finally, how have each of these sources changed in magnitude over the past ten to twenty years? To answer these questions, we use a geostatistical model-data fusion framework and spatial data on land use and economic activity. Using this approach, we estimate the contribution of different source types to methane emissions in the US and compare the magnitude of those anthropogenic emissions against natural fluxes from major wetlands like those near Hudson Bay, Canada. Furthermore, we examine the time-evolution of methane concentrations over regions dominated by agriculture and natural gas extraction and investigate what this data indicates about changes in emissions over time.

  3. 40 CFR Table 2 to Subpart Xxxx of... - Emission Limits for Tire Cord Production Affected Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Emission Limits for Tire Cord... POLLUTANTS FOR SOURCE CATEGORIES National Emissions Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX, Table 2 Table 2 to Subpart XXXX of Part 63—Emission Limits for Tire...

  4. Modeling and Electrostatic Focusing for a Field Emission Electron Source

    DTIC Science & Technology

    2013-06-01

    mechanisms of the beam formation, transport, field emission energy distributions, the effects of the emission properties, and parametric studies are...metals, the valence electrons possess the conduction energy band and are described by Sommerfeld free electron gas model with Fermi- Dirac statistics...which defines the electrons energy distribution. For the emission from not electrical conductors the Sommerfeld theory of metals with Fermi- Dirac

  5. RATE OF ACCLIMATION OF THE CAPACITY FOR ISOPRENE EMISSION IN RESPONSE TO LIGHT AND TEMPERATURE

    EPA Science Inventory

    Isoprene emission from plants accounts for nearly half of all non-methane hydrocarbons entering the atmosphere. Light and temperature regulate the instantaneous rate of isoprene emission, but there is increasing evidence that they also affect the capacity for isoprene emission (i...

  6. Is CO radio line emission a reliable mass-loss-rate estimator for AGB stars?

    NASA Astrophysics Data System (ADS)

    Ramstedt, Sofia; Scḧier, Frederik; Olofsson, Hans

    The final evolutionary stage of low- to intermediate-mass stars, as they evolve along the asymptotic giant branch (AGB), is characterized by mass loss so intense (10-8-10-4 Msol yr-1) that eventually the AGB life time is determined by it. The material lost by the star is enriched in nucleo-synthesized material and thus AGB stars play an important role in the chemical evolution of galaxies. A reliable mass-loss-rate estimator is of utmost importance in order to increase our understanding of late stellar evolution and to reach conclusions about the amount of enriched material recycled by AGB stars. For low-mass-loss-rate AGB stars, modelling of observed rotational CO radio line emission has proven to be a good tool for estimating mass-loss rates [Olofsson et al. (2002) for M-type stars and Schöier & Olofsson (2001) for carbon stars], but several lines are needed to get good constraints. For high-mass-loss-rate objects the situation is more complicated, the main reason being saturation of the optically thick CO lines. Moreover, Kemper et al. (2003) introduced temporal changes in the mass-loss rate, or alternatively, spatially varying turbulent motions, in order to explain observed line-intensity ratios. This puts into question whether it is possible to model the circumstellar envelope using a constant mass-loss rate, or whether the physical structure of the outflow is more complex than normally assumed. We present observations of CO radio line emission for a sample of intermediate- to high-mass-loss-rate AGB stars. The lowest rotational transition line (J =1-0) was observed at OSO and the higher-frequency lines (J =2-1, 3-2, 4-3 and in some cases 6-5) were observed at the JCMT. Using a detailed, non-LTE, radiative transfer model we are able to reproduce observed line ratios (Figure 1) and constrain the mass-loss rates for the whole sample, using a constant mass-loss rate and a "standard" circumstellar envelope model. However, for some objects only a lower limit to

  7. Gaseous mercury emissions from natural sources in Canadian landscapes

    NASA Astrophysics Data System (ADS)

    Schroeder, W. H.; Beauchamp, S.; Edwards, G.; Poissant, L.; Rasmussen, P.; Tordon, R.; Dias, G.; Kemp, J.; van Heyst, B.; Banic, C. M.

    2005-09-01

    Field measurements of mercury air-surface exchange from natural settings were made in various Canadian landscapes. Soil and water samples were analyzed for mercury concentrations, and air-surface exchange fluxes from these substrates were determined using dynamic chamber, micrometeorological, or modeling methods. Environmental variables, including air and soil/water temperature, solar radiation, humidity, and wind speed, were monitored concurrently with the air-surface exchange to better understand the processes affecting the environmental cycling of mercury. Average mercury fluxes from aquatic landscapes ranged from 0.0 to 5.0 ng m-2 h-1 with total mercury concentration in water ranging from 0.3 to 6.5 ng L-1. A significant correlation (R2 = 0.47) was found between gaseous Hg fluxes and total Hg concentration in water. Mean gaseous Hg fluxes from forest soils varied from -0.4 to 2.2 ng m-2 h-1, while those from agricultural fields ranged from 1.1 to 2.9 ng m-2 h-1. Non-mineralized bedrock, sand, and till sites yielded fluxes ranging from -0.03 to 5.9 ng m-2 h-1. Mean fluxes from mercuriferous geological substrates at various locations were large compared to non-mercuriferous sites, ranging from 9.1 to 1760 ng m-2 h-1, and represent natural emissions. The corresponding total mercury substrate concentrations ranged from 0.360 to 180 ppm. A significant correlation (R2 = 0.66) was found between Hg fluxes and total Hg concentrations in mineralized and non-mineralized substrates. These gaseous Hg flux measurements represent a significant contribution to understanding natural mercury cycling, but there are still insufficient data and knowledge of processes to properly scale up fluxes from natural sources in Canada.

  8. Emission characteristics of H- ion source with inverse gas magnetron geometrya)

    NASA Astrophysics Data System (ADS)

    Baturin, V. A.; Litvinov, P. A.; Pustovoitov, S. A.; Karpenko, A. Yu.

    2010-02-01

    The work is dedicated to the experimental investigation of the intense volume-plasma H- ion source. Preliminary experimental researches of two parameters of the upgraded source—emission density of H- ions and gas flow—are represented below. In plasma volume of noncesium H- ion source, the conditions for obtaining of increased density of H- ions in the field of adjoining to the emission aperture were realized. The advancing of electrode system of the emission chamber of a source has allowed receiving the value of an emission density of H- ions equal to 600 mA/cm2.

  9. 76 FR 35744 - Amendments to National Emission Standards for Hazardous Air Pollutants for Area Sources: Plating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ...On June 12, 2008, EPA issued national emission standards for control of hazardous air pollutants (HAP) for the plating and polishing area source category under section 112 of the Clean Air Act (CAA). In today's action, EPA is taking direct final action to amend the national emission standards for HAP (NESHAP) for the plating and polishing area source category. These final amendments clarify......

  10. RERANKING OF AREA SOURCES IN LIGHT OF SEASONAL/ REGIONAL EMISSION FACTORS AND STATE/LOCAL NEEDS

    EPA Science Inventory

    The report gives results of an effort to provide a better understanding of air pollution area sources and their emissions, to prioritize their importance as emitters of volatile organic compounds (VOCs), and to identify sources for which better emission estimation methodologies a...

  11. GLOBAL METHANE EMISSIONS FROM MINOR ANTHROPOGENIC SOURCES AND BIOFUEL COMBUSTION IN RESIDENTIAL STOVES (JOURNAL)

    EPA Science Inventory

    Most global methane (CH4) budgets have failed to include emissions from a diverse group of minor anthropogenic sources. Individually, these minor sources emit small quantities of CH4, but collectively, their contributions to the budget may be significant. In this paper, CH4 emiss...

  12. Emission Spectroscopy measurement of hybrid ECR-Helicon plasma source parameters

    NASA Astrophysics Data System (ADS)

    Hala, Ahmed

    2015-09-01

    Optical emission spectroscopy measurement of plasma temperature and density were conducted on KACST hybrid plasma source. The hybrid source involves ECR and helicon source operated simultanously. The results indicate that the ECR alone density is higher than the density of the combined sources while the combined temperature is lower.

  13. 40 CFR 63.843 - Emission limits for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., operate, and maintain equipment to capture and control POM emissions from each paste production plant. (1) The emission capture system shall be installed and operated to meet the generally accepted engineering... alternative control device to the applicable regulatory authority for review and approval. The request...

  14. 40 CFR 63.843 - Emission limits for existing sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., operate, and maintain equipment to capture and control POM emissions from each paste production plant. (1) The emission capture system shall be installed and operated to meet the generally accepted engineering... alternative control device to the applicable regulatory authority for review and approval. The request...

  15. 40 CFR 63.843 - Emission limits for existing sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., operate, and maintain equipment to capture and control POM emissions from each paste production plant. (1) The emission capture system shall be installed and operated to meet the generally accepted engineering... alternative control device to the applicable regulatory authority for review and approval. The request...

  16. [Status and needs research for on-line monitoring of VOCs emissions from stationary sources].

    PubMed

    Wang, Qiang; Zhou, Gang; Zhong, Qi; Zhao, Jin-Bao; Yang, Kai

    2013-12-01

    Based on atmospheric volatile organic compounds (VOCs) pollution control requirements during the twelfth-five year plan and the current status of monitoring and management in the world, instrumental architecture and technical characteristics of continuous emission monitoring systems (CEMS) for VOCs emission from stationary sources are investigated and researched. Technological development needs of VOCs emission on-line monitoring techniques for stationary sources in China are proposed from the system sampling pretreatment technology and analytical measurement techniques.

  17. Volatile organic compound concentrations and emission rates measured over one year in a new manufactured house

    SciTech Connect

    Hodgson, Alfred T.; Nabinger, Steven J.; Persily, Andrew K.

    2004-09-01

    A study to measure indoor concentrations and emission rates of volatile organic compounds (VOCs), including formaldehyde, was conducted in a new, unoccupied manufactured house installed at the National Institute of Standards and Technology (NIST) campus. The house was instrumented to continuously monitor indoor temperature and relative humidity, heating and air conditioning system operation, and outdoor weather. It also was equipped with an automated tracer gas injection and detection system to estimate air change rates every 2 h. Another automated system measured indoor concentrations of total VOCs with a flame ionization detector every 30 min. Active samples for the analysis of VOCs and aldehydes were collected indoors and outdoors on 12 occasions from August 2002 through September 2003. Individual VOCs were quantified by thermal desorption to a gas chromatograph with a mass spectrometer detector (GC/MS). Formaldehyde and acetaldehyde were quantified by high performance liquid chromatography (HPLC). Weather conditions changed substantially across the twelve active sampling periods. Outdoor temperatures ranged from 7 C to 36 C. House air change rates ranged from 0.26 h{sup -1} to 0.60 h{sup -1}. Indoor temperature was relatively constant at 20 C to 24 C for all but one sampling event. Indoor relative humidity (RH) ranged from 21% to 70%. The predominant and persistent indoor VOCs included aldehydes (e.g., formaldehyde, acetaldehyde, pentanal, hexanal and nonanal) and terpene hydrocarbons (e.g., a-pinene, 3-carene and d-limonene), which are characteristic of wood product emissions. Other compounds of interest included phenol, naphthalene, and other aromatic hydrocarbons. VOC concentrations were generally typical of results reported for other new houses. Measurements of total VOCs were used to evaluate short-term changes in indoor VOC concentrations. Most of the VOCs probably derived from indoor sources. However, the wall cavity was an apparent source of

  18. Crowd-Sourcing Management Activity Data to Drive GHG Emission Inventories in the Land Use Sector

    NASA Astrophysics Data System (ADS)

    Paustian, K.; Herrick, J.

    2015-12-01

    Greenhouse gas (GHG) emissions from the land use sector constitute the largest source category for many countries in Africa. Enhancing C sequestration and reducing GHG emissions on managed lands in Africa has to potential to attract C financing to support adoption of more sustainable land management practices that, in addition to GHG mitigation, can provide co-benefits of more productive and climate-resilient agroecosystems. However, robust systems to measure and monitor C sequestration/GHG reductions are currently a significant barrier to attracting more C financing to land use-related mitigation efforts.Anthropogenic GHG emissions are driven by a variety of environmental factors, including climate and soil attributes, as well as human-activities in the form of land use and management practices. GHG emission inventories typically use empirical or process-based models of emission rates that are driven by environmental and management variables. While a lack of field-based flux and C stock measurements are a limiting factor for GHG estimation, we argue that an even greater limitation may be availabiity of data on the management activities that influence flux rates, particularly in developing countries in Africa. In most developed countries there is a well-developed infrastructure of agricultural statistics and practice surveys that can be used to drive model-based GHG emission estimations. However, this infrastructure is largely lacking in developing countries in Africa. While some activity data (e.g. land cover change) can be derived from remote sensing, many key data (e.g., N fertilizer practices, residue management, manuring) require input from the farmers themselves. The explosive growth in cellular technology, even in many of the poorest parts of Africa, suggests the potential for a new crowd-sourcing approach and direct engagement with farmers to 'leap-frog' the land resource information model of developed countries. Among the many benefits of this approach

  19. GHG emissions during the high-rate production of compost using standard and advanced aeration strategies.

    PubMed

    Puyuelo, B; Gea, T; Sánchez, A

    2014-08-01

    In this study, we have evaluated different strategies for the optimization of the aeration during the active thermophilic stage of the composting process of source-selected Organic Fraction of Municipal Solid Waste (or biowaste) using reactors at bench scale (50L). These strategies include: typical cyclic aeration, oxygen feedback controller and a new self-developed controller based on the on-line maximization of the oxygen uptake rate (OUR) during the process. Results highlight differences found in the emission of most representative greenhouse gases (GHG) emitted from composting (methane and nitrous oxide) as well as in gases typically related to composting odor problems (ammonia as typical example). Specifically, the cyclic controller presents emissions that can double that of OUR controller, whereas oxygen feedback controller shows a better performance with respect to the cyclic controller. A new parameter, the respiration index efficiency, is presented to quantitatively evaluate the GHG emissions and, in consequence, the main negative environmental impact of the composting process. Other aspects such as the stability of the compost produced and the consumption of resources are also evaluated for each controller.

  20. Natural gas fugitive emissions rates constrained by global atmospheric methane and ethane.

    PubMed

    Schwietzke, Stefan; Griffin, W Michael; Matthews, H Scott; Bruhwiler, Lori M P

    2014-07-15

    The amount of methane emissions released by the natural gas (NG) industry is a critical and uncertain value for various industry and policy decisions, such as for determining the climate implications of using NG over coal. Previous studies have estimated fugitive emissions rates (FER)--the fraction of produced NG (mainly methane and ethane) escaped to the atmosphere--between 1 and 9%. Most of these studies rely on few and outdated measurements, and some may represent only temporal/regional NG industry snapshots. This study estimates NG industry representative FER using global atmospheric methane and ethane measurements over three decades, and literature ranges of (i) tracer gas atmospheric lifetimes, (ii) non-NG source estimates, and (iii) fossil fuel fugitive gas hydrocarbon compositions. The modeling suggests an upper bound global average FER of 5% during 2006-2011, and a most likely FER of 2-4% since 2000, trending downward. These results do not account for highly uncertain natural hydrocarbon seepage, which could lower the FER. Further emissions reductions by the NG industry may be needed to ensure climate benefits over coal during the next few decades.

  1. Feed Preparation for Source of Alkali Melt Rate Tests

    SciTech Connect

    Stone, M. E.; Lambert, D. P.

    2005-02-26

    The purpose of the Source of Alkali testing was to prepare feed for melt rate testing in order to determine the maximum melt-rate for a series of batches where the alkali was increased from 0% Na{sub 2}O in the frit (low washed sludge) to 16% Na{sub 2}O in the frit (highly washed sludge). This document summarizes the feed preparation for the Source of Alkali melt rate testing. The Source of Alkali melt rate results will be issued in a separate report. Five batches of Sludge Receipt and Adjustment Tank (SRAT) product and four batches of Slurry Mix Evaporator (SME) product were produced to support Source of Alkali (SOA) melt rate testing. Sludge Batch 3 (SB3) simulant and frit 418 were used as targets for the 8% Na{sub 2}O baseline run. For the other four cases (0% Na{sub 2}O, 4% Na{sub 2}O, 12% Na{sub 2}O, and 16% Na{sub 2}O in frit), special sludge and frit preparations were necessary. The sludge preparations mimicked washing of the SB3 baseline composition, while frit adjustments consisted of increasing or decreasing Na and then re-normalizing the remaining frit components. For all batches, the target glass compositions were identical. The five SRAT products were prepared for testing in the dry fed melt-rate furnace and the four SME products were prepared for the Slurry-fed Melt-Rate Furnace (SMRF). At the same time, the impacts of washing on a baseline composition from a Chemical Process Cell (CPC) perspective could also be investigated. Five process simulations (0% Na{sub 2}O in frit, 4% Na{sub 2}O in frit, 8% Na{sub 2}O in frit or baseline, 12% Na{sub 2}O in frit, and 16% Na{sub 2}O in frit) were completed in three identical 4-L apparatus to produce the five SRAT products. The SRAT products were later dried and combined with the complementary frits to produce identical glass compositions. All five batches were produced with identical processing steps, including off-gas measurement using online gas chromatographs. Two slurry-fed melter feed batches, a 4% Na

  2. Using an Explicit Emission Tagging Method in Global Modeling of Source-Receptor Relationships for Black Carbon in the Arctic: Variations, Sources and Transport Pathways

    SciTech Connect

    Wang, Hailong; Rasch, Philip J.; Easter, Richard C.; Singh, Balwinder; Zhang, Rudong; Ma, Po-Lun; Qian, Yun; Ghan, Steven J.; Beagley, Nathaniel

    2014-11-27

    We introduce an explicit emission tagging technique in the Community Atmosphere Model to quantify source-region-resolved characteristics of black carbon (BC), focusing on the Arctic. Explicit tagging of BC source regions without perturbing the emissions makes it straightforward to establish source-receptor relationships and transport pathways, providing a physically consistent and computationally efficient approach to produce a detailed characterization of the destiny of regional BC emissions and the potential for mitigation actions. Our analysis shows that the contributions of major source regions to the global BC burden are not proportional to the respective emissions due to strong region-dependent removal rates and lifetimes, while the contributions to BC direct radiative forcing show a near-linear dependence on their respective contributions to the burden. Distant sources contribute to BC in remote regions mostly in the mid- and upper troposphere, having much less impact on lower-level concentrations (and deposition) than on burden. Arctic BC concentrations, deposition and source contributions all have strong seasonal variations. Eastern Asia contributes the most to the wintertime Arctic burden. Northern Europe emissions are more important to both surface concentration and deposition in winter than in summer. The largest contribution to Arctic BC in the summer is from Northern Asia. Although local emissions contribute less than 10% to the annual mean BC burden and deposition within the Arctic, the per-emission efficiency is much higher than for major non-Arctic sources. The interannual variability (1996-2005) due to meteorology is small in annual mean BC burden and radiative forcing but is significant in yearly seasonal means over the Arctic. When a slow aging treatment of BC is introduced, the increase of BC lifetime and burden is source-dependent. Global BC forcing-per-burden efficiency also increases primarily due to changes in BC vertical distributions. The

  3. Nonlinear Source -" Receptor Relationship due to Interactions between Atmospheric Constituents, Water Cycle and Biogenic Emissions

    NASA Astrophysics Data System (ADS)

    Kinne, S.; Feichter, J.; Rast, S.; Bey, I.; Folberth, G.; Pozzoli, L.; Kloster, S.; Stier, P.

    2007-05-01

    Specific economic sectors or source regions emit a wide variety of air pollutants which influence climate and air quality. This includes emissions of greenhouse gases, chemical species which affect the oxidation capacity of the atmosphere and the concentrations of ozone and methane, and aerosol particles or aerosol precursors. Regional climate respectively weather controls transport and removal of pollutants, chemical transformation pathways, particle formation rate and sink processes as well as emissions from natural sources. Interactions between aerosols and trace gases modify their global and regional distributions. Thus, climatic and environmental impacts are not only controlled by amount and chemical composition of pollutant emissions but in addition also by their interactions and the local meteorological conditions in the source region. For the development of mitigation strategies to minimize adverse conditions attributed to climate change and air pollution we need a better understanding of the role of source location, impact of interactions and feedbacks and of the influence of climate change on the chemical composition of the atmosphere. To demonstrate interactions and feedbacks between the cycles of gaseous and particulate atmospheric constituents, the water cycle, the biosphere and the changing climate we will present results of a series of numerical model simulations. Investigations include interactions between greenhouse gas warming, water cycle and aerosol cycle (Feichter et al., 2004), between aerosol cycles (Stier et al., 2006), between marine biogeochemistry and aerosol cycles (Kloster et al., 2006), and between gas-phase air chemistry and aerosol constituents (Pozzoli et al., 2007). The presentation discusses possible interactions and feedbacks and emphasizes the need for a better integration of the different Earth system components in climate and air quality models. Finally, the question whether anthropogenic emissions from different regions

  4. What Is the Source of Quiet Sun Transition Region Emission?

    NASA Astrophysics Data System (ADS)

    Schmit, D. J.; De Pontieu, Bart

    2016-11-01

    Dating back to the first observations of the on-disk corona, there has been a qualitative link between the photosphere’s magnetic network and enhanced transition-temperature plasma emission. These observations led to the development of a general model that describes emission structures through the partitioning of the atmospheric volume with different magnetic loop geometries that exhibit different energetic equilibria. Does the internetwork produce transition-temperature emission? What fraction of network flux connects to the corona? How does quiet Sun emission compare with low-activity Sun-like stars? In this work, we revisit the canonical model of the quiet Sun, with high-resolution observations from the Interface Region Imaging Spectrograph (IRIS) and HMI in hand, to address those questions. We use over 900 deep exposures of Si iv 1393 Å from IRIS along with nearly simultaneous HMI magnetograms to quantify the correlation between transition-temperature emission structures and magnetic field concentrations through a number of novel statistics. Our observational results are coupled with analysis of the Bifrost MHD model and a large-scale potential field model. Our results paint a complex portrait of the quiet Sun. We measure an emission signature in the distant internetwork that cannot be attributed to network contribution. We find that the dimmest regions of emission are not linked to the local vertical magnetic field. Using the MHD simulation, we categorize the emission contribution from cool mid-altitude loops and high-altitude coronal loops and discuss the potential emission contribution of spicules. Our results provide new constraints on the coupled solar atmosphere so that we can build on our understanding of how dynamic thermal and magnetic structures generate the observed phenomena in the transition region.

  5. Comparison of emissions from on-road sources using a mobile laboratory under various driving and operational sampling modes

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Herndon, S. C.; Wood, E. C.; Jayne, J. T.; Nelson, D. D.; Trimborn, A. M.; Dunlea, E.; Knighton, W. B.; Mendoza, A.; Allen, D. T.; Kolb, C. E.; Molina, M. J.; Molina, L. T.

    2009-01-01

    Mobile sources produce a significant fraction of the total anthropogenic emissions burden in large cities and have harmful effects on air quality at multiple spatial scales. Mobile emissions are intrinsically difficult to estimate due to the large number of parameters affecting the emissions variability within and across vehicles types. The MCMA-2003 Campaign in Mexico City has showed the utility of using a mobile laboratory to sample and characterize specific classes of motor vehicles to better quantify their emissions characteristics as a function of their driving cycles. The technique clearly identifies "high emitter" vehicles via individual exhaust plumes, and also provides fleet average emission rates. We have applied this technique to Mexicali during the Border Ozone Reduction and Air Quality Improvement Program (BORAQIP) for the Mexicali-Imperial Valley in 2005. We analyze the variability of measured emission ratios for emitted NOx, CO, specific VOCs, NH3, and some primary fine particle components and properties by deploying a mobile laboratory in roadside stationary sampling, chase and fleet average operational sampling modes. The measurements reflect various driving modes characteristic of the urban fleets. The observed variability for all measured gases and particle emission ratios is greater for the chase and roadside stationary sampling than for fleet average measurements. The fleet average sampling mode captured the effects of traffic conditions on the measured on-road emission ratios, allowing the use of fuel-based emission ratios to assess the validity of traditional "bottom-up" emissions inventories. Using the measured on-road emission ratios, we estimate CO and NOx mobile emissions of 175±62 and 10.4±1.3 metric tons/day, respectively, for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road emissions data from Mexico City indicated that fleet average NO emission ratios were around 20% higher in Mexicali than in Mexico City

  6. Comparison of emission ratios from on-road sources using a mobile laboratory under various driving and operational sampling modes

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Herndon, S. C.; Wood, E. C.

    2008-04-01

    Mobile sources produce a significant fraction of the total anthropogenic emissions burden in large cities and have harmful effects on air quality at multiple spatial scales. Mobile emissions are intrinsically difficult to estimate due to the large number of parameters affecting the emissions variability within and across vehicles types. The MCMA-2003 Campaign in Mexico City has showed the utility of using a mobile laboratory to sample and characterize specific classes of motor vehicles to better quantify their emissions characteristics as a function of their driving cycles. The technique clearly identifies "high emitter" vehicles via individual exhaust plumes, and also provides fleet average emission rates. We have applied this technique to Mexicali during the Border Ozone Reduction and Air Quality Improvement Program for the Mexicali-Imperial Valley in 2005. In this paper we analyze the variability of measured emission ratios for emitted NOx, CO, specific VOCs, NH3, and some primary fine particle components and properties obtained during the Border Ozone Reduction and Air Quality Improvement Program for the Mexicali-Imperial Valley in 2005 by deploying a mobile laboratory in roadside stationary sampling, chase and fleet average operational sampling modes. The measurements reflect various driving modes characteristic of the urban fleets. The observed variability for all measured gases and particle emission ratios is greater for the chase and roadside stationary sampling than for fleet average measurements. The fleet average sampling mode captured the effects of traffic conditions on the measured on-road emission ratios, allowing the use of fuel-based emission ratios to assess the validity of traditional "bottom-up" emissions inventories. Using the measured on-road emission ratios, we estimate CO and NOx mobile emissions of 175±62 and 10.4±1.3 metric tons/day, respectively, for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road emissions data

  7. Source emission and model evaluation of formaldehyde from composite and solid wood furniture in a full-scale chamber

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyu; Mason, Mark A.; Guo, Zhishi; Krebs, Kenneth A.; Roache, Nancy F.

    2015-12-01

    This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber at different ventilation rates for up to 4000 h using ASTM D 6670-01 (2007). Tests were performed on four types of furniture constructed of different materials and from different manufacturers. The data were used to evaluate two empirical emission models, i.e., a first-order and power-law decay model. The experimental results showed that some furniture tested in this study, made only of solid wood and with less surface area, had low formaldehyde source emissions. The effect of ventilation rate on formaldehyde emissions was also examined. Model simulation results indicated that the power-law decay model showed better agreement than the first-order decay model for the data collected from the tests, especially for long-term emissions. This research was limited to a laboratory study with only four types of furniture products tested. It was not intended to comprehensively test or compare the large number of furniture products available in the market place. Therefore, care should be taken when applying the test results to real-world scenarios. Also, it was beyond the scope of this study to link the emissions to human exposure and potential health risks.

  8. Characterization, concentrations and emission rates of polycyclic aromatic hydrocarbons in the exhaust emissions from in-service vehicles in Damascus

    NASA Astrophysics Data System (ADS)

    Alkurdi, Farouk; Karabet, François; Dimashki, Marwan

    2013-02-01

    Motor vehicles are significant sources of polycyclic aromatic hydrocarbon (PAH) emissions to the urban atmosphere. Improved understanding of PAH emission profiles in mobile sources is the key to determining the viable approach for reducing PAH emissions from motor vehicles. Very limited data is available on the levels of PAH emissions in the urban atmospheres in Syria and no data are currently available on the level of PAH emissions from different combustion sources in the country. The aim of this study was to determine the profile and concentration of PAH in exhaust emissions of light and heavy-duty vehicles running on the roads of Damascus city. Three different types of vehicles (passenger cars, minivans and buses) were selected along with different age groups. Vapor- and particulate-phase PAH were collected from the vehicular exhausts of six in-service vehicles (with/without catalytic converters). High-performance liquid chromatography system, equipped with UV-Visible and fluorescence detectors, was used for the identification and quantification of PAH compounds in the cleaned extracts of the collected samples. The mean concentration of total PAH emissions (sum of 15 compounds) from all types of studied vehicles ranged between 69.28 ± 1.06 μg/m3 for passenger cars equipped with catalytic converters and 2169.41 ± 5.17 μg/m3 for old diesel buses without pollution controls. Values of total benzo(a)pyrene equivalent (∑ B[a]Peq) ranged between 1.868 μg/m3and 37.652 μg/m3. The results obtained in this study showed that the use of catalytic converters resulted into cleaner exhaust compositions and emissions with characteristics that are distinct from those obtained in the absence of catalytic converters.

  9. Dosimetric Study of a Low-Dose-Rate Brachytherapy Source

    NASA Astrophysics Data System (ADS)

    Rodríguez-Villafuerte, M.; Arzamendi, S.; Díaz-Perches, R.

    Carcinoma of the cervix is the most common malignancy - in terms of both incidence and mortality - in Mexican women. Low dose rate (LDR) intracavitary brachytherapy is normally prescribed for the treatment of this disease to the vast majority of patients attending public hospitals in our country. However, most treatment planning systems being used in these hospitals still rely on Sievert integral dose calculations. Moreover, experimental verification of dose distributions are hardly ever done. In this work we present a dosimetric characterisation of the Amersham CDCS-J 137Cs source, an LDR brachytherapy source commonly used in Mexican hospitals. To this end a Monte Carlo simulation was developed, that includes a realistic description of the internal structure of the source embedded in a scattering medium. The Monte Carlo results were compared to experimental measurements of dose distributions. A lucite phantom with the same geometric characteristics as the one used in the simulation was built. Dose measurements were performed using thermoluminescent dosimeters together with commercial RadioChromic dye film. A comparison between our Monte Carlo simulation, the experimental data, and results reported in the literature is presented.

  10. Black carbon emissions from Russian diesel sources: case study of Murmansk

    NASA Astrophysics Data System (ADS)

    Evans, M.; Kholod, N.; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-02-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), fishing and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emission in Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 70% of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source emitting about 12% of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 56.7 Gg in 2010, and on-road transport contributed 55% of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  11. Black carbon emissions from Russian diesel sources: case study of Murmansk

    NASA Astrophysics Data System (ADS)

    Evans, M.; Kholod, N.; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-07-01

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), ships and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emissions in the Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 69 % of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source, emitting about 13 % of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 50.8 Gg in 2010, and on-road transport contributed 49 % of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  12. Black carbon emissions from Russian diesel sources. Case study of Murmansk

    DOE PAGES

    Evans, M.; Kholod, N.; Malyshev, V.; ...

    2015-07-27

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), ships and diesel generators. For on-road transport, we conducted several surveys tomore » understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emissions in the Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 69 % of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source, emitting about 13 % of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 50.8 Gg in 2010, and on-road transport contributed 49 % of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.« less

  13. Black carbon emissions from Russian diesel sources. Case study of Murmansk

    SciTech Connect

    Evans, M.; Kholod, N.; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2015-07-27

    Black carbon (BC) is a potent pollutant because of its effects on climate change, ecosystems and human health. Black carbon has a particularly pronounced impact as a climate forcer in the Arctic because of its effect on snow albedo and cloud formation. We have estimated BC emissions from diesel sources in the Murmansk Region and Murmansk City, the largest city in the world above the Arctic Circle. In this study we developed a detailed inventory of diesel sources including on-road vehicles, off-road transport (mining, locomotives, construction and agriculture), ships and diesel generators. For on-road transport, we conducted several surveys to understand the vehicle fleet and driving patterns, and, for all sources, we also relied on publicly available local data sets and analysis. We calculated that BC emissions in the Murmansk Region were 0.40 Gg in 2012. The mining industry is the largest source of BC emissions in the region, emitting 69 % of all BC emissions because of its large diesel consumption and absence of emissions controls. On-road vehicles are the second largest source, emitting about 13 % of emissions. Old heavy duty trucks are the major source of emissions. Emission controls on new vehicles limit total emissions from on-road transportation. Vehicle traffic and fleet surveys show that many of the older cars on the registry are lightly or never used. We also estimated that total BC emissions from diesel sources in Russia were 50.8 Gg in 2010, and on-road transport contributed 49 % of diesel BC emissions. Agricultural machinery is also a significant source Russia-wide, in part because of the lack of controls on off-road vehicles.

  14. Historic Emissions from Deforestation and Forest Degradation in Mato Grosso, Brazil: 1. Source Data Uncertainties

    NASA Technical Reports Server (NTRS)

    Morton, Douglas C.; Sales, Marcio H.; Souza, Carlos M., Jr.; Griscom, Bronson

    2011-01-01

    Historic carbon emissions are an important foundation for proposed efforts to Reduce Emissions from Deforestation and forest Degradation and enhance forest carbon stocks through conservation and sustainable forest management (REDD+). The level of uncertainty in historic carbon emissions estimates is also critical for REDD+, since high uncertainties could limit climate benefits from mitigation actions. Here, we analyzed source data uncertainties based on the range of available deforestation, forest degradation, and forest carbon stock estimates for the Brazilian state of Mato Grosso during 1990-2008. Results: Deforestation estimates showed good agreement for multi-year trends of increasing and decreasing deforestation during the study period. However, annual deforestation rates differed by >20% in more than half of the years between 1997-2008, even for products based on similar input data. Tier 2 estimates of average forest carbon stocks varied between 99-192 Mg C/ha, with greatest differences in northwest Mato Grosso. Carbon stocks in deforested areas increased over the study period, yet this increasing trend in deforested biomass was smaller than the difference among carbon stock datasets for these areas. Conclusions: Patterns of spatial and temporal disagreement among available data products provide a roadmap for future efforts to reduce source data uncertainties for estimates of historic forest carbon emissions. Specifically, regions with large discrepancies in available estimates of both deforestation and forest carbon stocks are priority areas for evaluating and improving existing estimates. Full carbon accounting for REDD+ will also require filling data gaps, including forest degradation and secondary forest, with annual data on all forest transitions.

  15. Identifying sensitive sources and key control handles for the reduction of greenhouse gas emissions from wastewater treatment.

    PubMed

    Sweetapple, Christine; Fu, Guangtao; Butler, David

    2014-10-01

    This research investigates the effects of adjusting control handle values on greenhouse gas emissions from wastewater treatment, and reveals critical control handles and sensitive emission sources for control through the combined use of local and global sensitivity analysis methods. The direction of change in emissions, effluent quality and operational cost resulting from variation of control handles individually is determined using one-factor-at-a-time sensitivity analysis, and corresponding trade-offs are identified. The contribution of each control handle to variance in model outputs, taking into account the effects of interactions, is then explored using a variance-based sensitivity analysis method, i.e., Sobol's method, and significant second order interactions are discovered. This knowledge will assist future control strategy development and aid an efficient design and optimisation process, as it provides a better understanding of the effects of control handles on key performance indicators and identifies those for which dynamic control has the greatest potential benefits. Sources with the greatest variance in emissions, and therefore the greatest need to monitor, are also identified. It is found that variance in total emissions is predominantly due to changes in direct N2O emissions and selection of suitable values for wastage flow rate and aeration intensity in the final activated sludge reactor is of key importance. To improve effluent quality, costs and/or emissions, it is necessary to consider the effects of adjusting multiple control handles simultaneously and determine the optimum trade-off.

  16. GLOBAL INVENTORY OF VOLATILE COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    The report describes a global inventory anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds....

  17. Non-point source mercury emission from the Idrija Hg-mine region: GIS mercury emission model.

    PubMed

    Kocman, David; Horvat, Milena

    2011-08-01

    A mercury emission model was developed to estimate non-point source mercury (Hg) emissions occurring over the year from the Idrijca River catchment, draining the area of the world's second largest Hg mine in Idrija, Slovenia. Site-specific empirical correlations between the measured Hg emission fluxes and the parameters controlling the emission (comprising substrate Hg content, soil temperature, solar radiation and soil moisture) were incorporated into the mercury emission model developed using Geographic Information System technology. In this way, the spatial distribution and significance of the most polluted sites that need to be properly managed was assessed. The modelling results revealed that annually approximately 51 kg of mercury are emitted from contaminated surfaces in the catchment (640 km(2)), highlighting that emission from contaminated surfaces contributes significantly to the elevated Hg concentrations in the ambient air of the region. Very variable meteorological conditions in the modelling domain throughout the year resulted in the high seasonal and spatial variations of mercury emission fluxes observed. Moreover, it was found that mercury emission fluxes from surfaces in the Idrija region are 3-4 fold higher than the values commonly used in models representing emissions from global mercuriferous belts. Sensitivity and model uncertainty analysis indicated the importance of knowing not only the amount but also the type of mercury species and their binding in soils in future model development.

  18. Megacity and country emissions from combustion sources-Buenos Aires-Argentina

    NASA Astrophysics Data System (ADS)

    Dawidowski, L.; Gomez, D.; Matranga, M.; D'Angiola, A.; Oreggioni, G.

    2010-12-01

    Historic time series (1970-2006) emissions of greenhouse gases and air pollutants arising from stationary and mobile combustion sources were estimated at national level for Argentina and at regional level for the metropolitan area of Buenos Aires (MABA). All emissions were estimated using a bottom-up approach following the IPCC good practice guidance. For mobile sources, national emissions include all transport categories. Regional emissions account thus far only for on-road. For national emissions, methodologies and guidance by the IPCC were employed, applying the highest possible tier and using: i)country-specific emission factors for carbon and sulphur and technology-based information for other species, ii)activity data from energy balance series (1970-2007), and iii)complementary information concerning the non-energy use of fuels. Regional emissions in 2006 were estimated in-depth using a technology-based approach for the city of Buenos Aires (CBA) and the 24 neighboring districts composing the MABA. A regional emissions factors database was developed to better characterize Latin American fleets and driving conditions employing COPERT III-IV algorithms and emission factors measured in dynamometers and circulating vehicles in Argentina, Brazil, Chile and Colombia. Past emissions were back estimated from 2005 to 1970 using the best available information, which differs greatly among categories, spatial disaggregation and time periods. The time series of stationary and mobile combustion sources at the national and regional level allowed the identification of distinct patterns. National greenhouse gas emissions in 2006 amounted to ~ 150 million ton CO2-equivalent, 70% of which were contributed by stationary sources. On-road transport was the major contributor within mobile sources (28.1 %). The increasing emissions trends are dominated by on-road transport, agriculture and residential categories while the variability is largely associated with energy industries

  19. Sources of persistent organic pollutants emission on the territory of Belarus

    NASA Astrophysics Data System (ADS)

    Kakareka, Sergey V.

    The paper considers selected persistent organic pollutants (POPs) atmospheric emission evaluation on the territory of Belarus for main source categories. The procedure applied was based on the UNECE EMEP methodology. Data of industrial statistics, production processes analysis and relevant emission factors were used. For a number of sources, only quality and semi-quality emission evaluation was conducted, due to the lack of information for the selection of emission factors or statistical data relevant. In the paper, emissions of the following groups of pollutants are discussed: dioxins/furans (PCDD/PCDF) and polychlorinated biphenyls (PCB) as requested for EMEP database (Protocol on Persistent Organic Pollutants to the convention of 1979 on Long-range Transboundary Air Pollution in Europe and Annexes I, II, or III to the Protocol, 1998). PAH emission and selected chlorinated pesticides input also requested by EMEP will be described in other issues. Estimations have showed that Belarus as a whole is not a large emission source of such POPs as dioxins. Its share in European emissions is significantly below 1%. This can be explained by the fact that in Belarus there are no such large dioxin emission sources like sintering, waste incineration, non-ferrous industry. But some important sources of dioxins/furans for instance, open burning are not included in quantitative estimation now. The main contribution to dioxin emissions is by firewood and peat combustion. Only electric steel smelting plant can be considered as a large emission point source. Leakage from transformers and damaged capacitors was estimated as the main source of polychlorinated biphenyls (PCB) discharged into the environment: dielectric fluids with PCB are still in use in electrical equipment.

  20. PM 2.5 source profiles for black and organic carbon emission inventories

    NASA Astrophysics Data System (ADS)

    Chow, Judith C.; Watson, John G.; Lowenthal, Douglas H.; Antony Chen, L.-W.; Motallebi, Nehzat

    2011-10-01

    Emission inventories for black or elemental (BC or EC) and organic (OC) carbon can be derived by multiplying PM 2.5 emission estimates by mass fractions of these species in representative source profiles. This study examines the variability of source profiles and its effect on EC emission estimates. An examination of available profiles shows that EC and OC ranged from 6-13% and 35-40% for agricultural burning, 4-33% and 22-68% for residential wood combustion, 6-38% and 24-75% for on-road gasoline vehicles, and 33-74% and 20-47% for on-road heavy-duty diesel vehicles, respectively. Source profiles from the U.S. EPA SPECIATE data base were applied to PM 2.5 emissions from the U.S. EPA National Emissions Inventory for 2005. The total estimated EC emissions of 432 Gg yr -1 was apportioned as 42.5% from biomass burning, 35.4% from non-road mobile sources, 15% from on-road mobile sources, 5.4% from fossil fuel (e.g., coal, oil, and natural gas) combustion in stationary sources, 1% from other stationary industrial sources, and 0.5% from fugitive dust. Considering the variability in available source profiles, BC emission estimates for major sources such as open fires and non-road diesels ranged from 42 to 133 (a factor of 3) and 25 to 100 (a factor of 4) Gg yr -1, respectively. The choice of source profiles can be a major source of uncertainty in national and global BC/EC emission inventories.

  1. High resolution European emission grids for anthropogenic sources for the years 2003-2007

    NASA Astrophysics Data System (ADS)

    Denier van der Gon, Hugo; Visschedijk, Antoon; Kuenen, Jeroen; van der Brugh, Hans; Dröge, Rianne; Schaap, Martijn

    2010-05-01

    To develop atmospheric services such as forecasting atmospheric composition a combination of meteorological models, atmospheric chemical transport models, satellite observational data and emission grids are needed. The latter are input for the predictive models and need to be as accurate as possible both in time and space. To support the new EU FP7 MACC (Monitoring Atmospheric Composition and Climate) we developed high resolution (1/8 degree x 1/16 degree lon-lat or ~ 7 x7 km) emission grids for UNECE-Europe for the years 2003-2007. These years are the focus of a reanalysis exercise within MACC. Reanalysis datasets are produced with data assimilation and modelling systems applied to the best available observational datasets. Such reanalysed fields of climate and atmospheric composition can be used in other studies (e.g. IPCC) to make more accurate assessments. For the MACC reanalysis years we use a combination of official reported emission data as available from EMEP, the IIASA GAINS model and expert estimates resulting in a consistent emission data set by country by source category for these years. From 2003-2007 emissions of air pollutants decreased by about 5%, although the reduction of NH3 emission was less (2.3%) and SO2 reduction was more (13%). However, more remarkable than the overall changes are the regional differences as well as source sector differences. For example, NOx emissions changed by -12% in the EU15+NOR+CHE, -8% in the EU12 and + 6 % in the non-EU countries. The emissions are distributed using our newly developed year 2005 emission database which is partly developed in EU FP7 MEGAPOLI. This database distinguishes itself from previous emission databases by a much improved spatial allocation of emissions. To this end we checked and updated our point source database by adding new point sources and removing obsolete entries for power plants, refineries and industrial installations. For diffuse sources like transport, residential combustion and

  2. Premature deaths attributed to source-specific BC emissions in six urban US regions

    NASA Astrophysics Data System (ADS)

    Turner, Matthew D.; Henze, Daven K.; Capps, Shannon L.; Hakami, Amir; Zhao, Shunliu; Resler, Jaroslav; Carmichael, Gregory R.; Stanier, Charles O.; Baek, Jaemeen; Sandu, Adrian; Russell, Armistead G.; Nenes, Athanasios; Pinder, Rob W.; Napelenok, Sergey L.; Bash, Jesse O.; Percell, Peter B.; Chai, Tianfeng

    2015-11-01

    Recent studies have shown that exposure to particulate black carbon (BC) has significant adverse health effects and may be more detrimental to human health than exposure to PM2.5 as a whole. Mobile source BC emission controls, mostly on diesel-burning vehicles, have successfully decreased mobile source BC emissions to less than half of what they were 30 years ago. Quantification of the benefits of previous emissions controls conveys the value of these regulatory actions and provides a method by which future control alternatives could be evaluated. In this study we use the adjoint of the Community Multiscale Air Quality (CMAQ) model to estimate highly-resolved spatial distributions of benefits related to emission reductions for six urban regions within the continental US. Emissions from outside each of the six chosen regions account for between 7% and 27% of the premature deaths attributed to exposure to BC within the region. While we estimate that nonroad mobile and onroad diesel emissions account for the largest number of premature deaths attributable to exposure to BC, onroad gasoline is shown to have more than double the benefit per unit emission relative to that of nonroad mobile and onroad diesel. Within the region encompassing New York City and Philadelphia, reductions in emissions from large industrial combustion sources that are not classified as EGUs (i.e., non-EGU) are estimated to have up to triple the benefits per unit emission relative to reductions to onroad diesel sectors, and provide similar benefits per unit emission to that of onroad gasoline emissions in the region. While onroad mobile emissions have been decreasing in the past 30 years and a majority of vehicle emission controls that regulate PM focus on diesel emissions, our analysis shows the most efficient target for stricter controls is actually onroad gasoline emissions.

  3. Bayesian analysis of energy and count rate data for detection of low count rate radioactive sources.

    PubMed

    Klumpp, John; Brandl, Alexander

    2015-03-01

    A particle counting and detection system is proposed that searches for elevated count rates in multiple energy regions simultaneously. The system analyzes time-interval data (e.g., time between counts), as this was shown to be a more sensitive technique for detecting low count rate sources compared to analyzing counts per unit interval (Luo et al. 2013). Two distinct versions of the detection system are developed. The first is intended for situations in which the sample is fixed and can be measured for an unlimited amount of time. The second version is intended to detect sources that are physically moving relative to the detector, such as a truck moving past a fixed roadside detector or a waste storage facility under an airplane. In both cases, the detection system is expected to be active indefinitely; i.e., it is an online detection system. Both versions of the multi-energy detection systems are compared to their respective gross count rate detection systems in terms of Type I and Type II error rates and sensitivity.

  4. Fast pulsed operation of a small non-radioactive electron source with continuous emission current control

    SciTech Connect

    Cochems, P.; Kirk, A. T.; Bunert, E.; Runge, M.; Goncalves, P.; Zimmermann, S.

    2015-06-15

    Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron current due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.

  5. Quantitative analysis of directional spontaneous emission spectra from light sources in photonic crystals

    SciTech Connect

    Nikolaev, Ivan S.; Lodahl, Peter; Vos, Willem L.

    2005-05-15

    We have performed angle-resolved measurements of spontaneous-emission spectra from laser dyes and quantum dots in opal and inverse opal photonic crystals. Pronounced directional dependencies of the emission spectra are observed: angular ranges of strongly reduced emission adjoin with angular ranges of enhanced emission. It appears that emission from embedded light sources is affected both by the periodicity and by the structural imperfections of the crystals: the photons are Bragg diffracted by lattice planes and scattered by unavoidable structural disorder. Using a model comprising diffuse light transport and photonic band structure, we quantitatively explain the directional emission spectra. This work provides detailed understanding of the transport of spontaneously emitted light in real photonic crystals, which is essential in the interpretation of quantum optics in photonic-band-gap crystals and for applications wherein directional emission and total emission power are controlled.

  6. The Role of the Jet Emission in Young Radio Sources

    NASA Astrophysics Data System (ADS)

    Migliori, Giulia

    2014-07-01

    We investigated the contribution of the jet to the observed high energy emission in a sample of young and compact radio quasars. For the first time, we compared the Fermi-LAT and Chandra observations of the sample to γ-ray and X-ray luminosities predicted assuming a jet synchrotron and inverse Compton radiative model. The simulations performed for a reasonable set of model parameters and assumptions provide constraints on the minimum jet power (Ljet,kin/Ldisk >0.01), on the contribution of the jet to the X-ray emission, and on the particles to magnetic field energy density ratios.

  7. Source location of the smooth high-frequency radio emissions from Uranus

    SciTech Connect

    Farrell, W.M.; Calvert, W. )

    1989-05-01

    The source location of the smooth high-frequency (SHF) radio emissions from Uranus has been determined using a technique differing from those applied previously. Specifically, by fitting the signal dropouts which occurred as Voyager traversed the hollow center for the emission pattern to a symmetrical cone centered on the source magnetic field direction at the cyclotron frequency, a southern-hemisphere (nightside) source was found at approximately 56{degree} S, 219{degree} W. The half-angle for the hollow portion of the emission pattern was found to be 13{degree}.

  8. Contribution of Changing Sources and Sinks to the Growth Rate of Atmospheric Methane Concentrations for the Last Two Decades

    NASA Technical Reports Server (NTRS)

    Matthews, Elaine; Walter, B.; Bogner, J.; Sarma, D.; Portmey, G.; Travis, Larry (Technical Monitor)

    2001-01-01

    In situ measurements of atmospheric methane concentrations begun in the early 1980s show decadal trends, as well as large interannual variations, in growth rate. Recent research indicates that while wetlands can explain several of the large growth anomalies for individual years, the decadal trend may be the combined effect of increasing sinks, due to increases in tropospheric OH, and stabilizing sources. We discuss new 20-year histories of annual, global source strengths for all major methane sources, i.e., natural wetlands, rice cultivation, ruminant animals, landfills, fossil fuels, and biomass burning. We also present estimates of the temporal pattern of the sink required to reconcile these sources and atmospheric concentrations over this time period. Analysis of the individual emission sources, together with model-derived estimates of the OH sink strength, indicates that the growth rate of atmospheric methane observed over the last 20 years can only be explained by a combination of changes in source emissions and an increasing tropospheric sink. Direct validation of the global sources and the terrestrial sink is not straightforward, in part because some sources/sinks are relatively small and diffuse (e.g., landfills and soil consumption), as well as because the atmospheric record integrates multiple and substantial sources and tropospheric sinks in regions such as the tropics. We discuss ways to develop and test criteria for rejecting and/or accepting a suite of scenarios for the methane budget.

  9. Compilation of a source profile database for hydrocarbon and OVOC emissions in China

    NASA Astrophysics Data System (ADS)

    Mo, Ziwei; Shao, Min; Lu, Sihua

    2016-10-01

    Source profiles are essential for quantifying the role of volatile organic compound (VOC) emissions in air pollution. This study compiled a database of VOC source profiles in China, with 75 species drawn from five major categories: transportation, solvent use, biomass burning, fossil fuel burning, and industrial processes. Source profiles were updated for diesel vehicles, biomass burning, and residential coal burning by measuring both hydrocarbons and oxygenated VOCs (OVOCs), while other source profiles were derived from the available literature. The OVOCs contributed 53.8% of total VOCs in the profiles of heavy - duty diesel vehicle exhaust and 12.4%-46.3% in biomass and residential coal burning, which indicated the importance of primary OVOCs emissions from combustion-related sources. Taking the national emission inventory from 2008 as an example, we established an approach for assigning source profiles to develop a speciation-specific VOC and OVOC emission inventory. The results showed that aromatics contributed 30% of the total 26 Tg VOCs, followed by alkanes (24%), alkenes (19%) and OVOCs (12%). Aromatics (7.9 Tg) were much higher than in previous results (1.1 Tg and 3.4 Tg), while OVOCs (3.1 Tg) were comparable with the 3.3 Tg and 4.3 Tg reported in studies using profiles from the US. The current emission inventories were built based on emission factors from non-methane hydrocarbon measurements, and therefore the proportions from OVOC emissions was neglected, leading to up to 30% underestimation of total VOC emissions. As a result, there is a need to deploy appropriate emission factors and source profiles that include OVOC measurements to reduce the uncertainty of estimated emissions and chemical reactivity potential.

  10. Modeling Ozone in the Eastern United States Using a Fuel-Based Mobile Source Emissions Inventory

    NASA Astrophysics Data System (ADS)

    Mcdonald, B. C.; Ahmadov, R.; McKeen, S. A.; Kim, S. W.; Frost, G. J.; Trainer, M.

    2015-12-01

    A fuel-based mobile source emissions inventory of nitrogen oxides (NOx) and carbon monoxide (CO) is developed for the continental US. Emissions are mapped for the year 2013, including emissions from on-road gasoline and diesel vehicles, and off-road engines. We find that mobile source emissions of NOx in the National Emissions Inventory 2011 (NEI11) are 50-60% higher than results from this study; mobile sources contribute around half of total US anthropogenic NOx emissions. We model chemistry and transport of emissions from the NEI11 and our fuel-based inventory during the Southeast Nexus (SENEX) Study period in the summer of 2013, using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. In the Eastern US, there is a consistent over-prediction of tropospheric ozone (O3) levels when simulating emissions from the NEI11, with the largest biases located in the Southeastern US. Using our fuel-based inventory, we test O3 sensitivity to lower NOx emissions. We highlight results in the Southeast, a region with significant interactions between anthropogenic and biogenic emissions of ozone precursors. Model results of NOy, CO, and O3 are compared with aircraft measurements made during SENEX.

  11. A Global inventory of volatile organic compound emissions from anthropogenic sources

    NASA Astrophysics Data System (ADS)

    Piccot, Stephen D.; Watson, Joel J.; Jones, Julian W.

    1992-06-01

    As part of an effort to assess the potential impacts associated with global climate change, the U.S. Environmental Protection Agency's Office of Research and Development is supporting global atmospheric chemistry research by developing global scale estimates of volatile organic compound (VOC) emissions (excluding methane). Atmospheric chemistry models require, as one input, an emissions inventory of VOCs. Consequently, a global inventory of anthropogenic VOC emissions has been developed. The inventory includes VOC estimates for seven classes of VOCs: paraffins, olefins, aromatics (benzene, toluene, xylene), formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds. These classes represent general classes of VOC compounds which possess different chemical reactivities in the atmosphere. The technical approach used to develop this inventory involved four major steps. The first step was to identify the major anthropogenic sources of VOC emissions in the United States and to group these sources into 28 general source groups. Source groups were developed to represent general categories such as "sources associated with oil and natural gas production" and more specific categories such as savanna buming. Emission factors for these source groups were then developed using different techniques and data bases. For example, emission factors for oil and natural gas production were estimated by dividing the United States' emissions from oil and gas production operations by the amount of oil and natural gas produced in the United States. Multiplication of these emission factors by production/consumption statistics for other countries yielded global VOC emission estimates for specific source groups within those countries. The final step in development of the VOC inventory was to distribute emissions into 10° by 10° grid cells using detailed maps of population and industrial activity. The results of this study show total global anthropogenic VOC emissions of

  12. Diffuse gas in retired galaxies: nebular emission templates and constraints on the sources of ionization

    NASA Astrophysics Data System (ADS)

    Johansson, Jonas; Woods, Tyrone E.; Gilfanov, Marat; Sarzi, Marc; Chen, Yan-Mei; Oh, Kyuseok

    2016-10-01

    We present emission-line templates for passively-evolving (`retired') galaxies, useful for investigation of the evolution of the interstellar medium in these galaxies, and characterization of their high-temperature source populations. The templates are based on high signal-to-noise (>800) co-added spectra (3700-6800 Å) of ˜11 500 gas-rich Sloan Digital Sky Survey galaxies devoid of star formation and active galactic nuclei. Stacked spectra are provided for the entire sample and sub-samples binned by mean stellar age. In our previous paper, Johansson et al., these spectra provided the first measurements of the He II 4686 Å line in passively-evolving galaxies, and the observed He II/Hβ ratio constrained the contribution of accreting white dwarfs (the `single-degenerate' scenario) to the Type Ia supernova rate. In this paper, the full range of unambiguously detected emission lines are presented. Comparison of the observed [O I] 6300 Å/Hα ratio with photoionization models further constrains any high-temperature single-degenerate scenario for Type Ia supernovae (with 1.5 ≲ T/105 K ≲ 10) to ≲3-6 per cent of the observed rate in the youngest age bin (i.e. highest SN Ia rate). Hence, for the same temperatures, in the presence of an ambient population of post-asymptotic giant branch stars, we exclude additional high-temperature sources with a combined ionizing luminosity of ≈1.35 × 1030 L⊙/M⊙,* for stellar populations with mean ages of 1-4 Gyr. Furthermore, we investigate the extinction affecting both the stellar and nebular continuum. The latter shows about five times higher values. This contradicts isotropically distributed dust and gas that renders similar extinction values for both cases.

  13. Handling high data rate detectors at Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Pedersen, U. K.; Rees, N.; Basham, M.; Ferner, F. J. K.

    2013-03-01

    An increasing number of area detectors, in use at Diamond Light Source, produce high rates of data. In order to capture, store and process this data High Performance Computing (HPC) systems have been implemented. This paper will present the architecture and usage for handling high rate data: detector data capture, large volume storage and parallel processing. The EPICS area Detector frame work has been adopted to abstract the detectors for common tasks including live processing, file format and storage. The chosen data format is HDF5 which provides multidimensional data storage and NeXuS compatibility. The storage system and related computing infrastructure include: a centralised Lustre based parallel file system, a dedicated network and a HPC cluster. A well defined roadmap is in place for the evolution of this to meet demand as the requirements and technology advances. For processing the science data the HPC cluster allow efficient parallel computing, on a mixture of ×86 and GPU processing units. The nature of the Lustre storage system in combination with the parallel HDF5 library allow efficient disk I/O during computation jobs. Software developments, which include utilising optimised parallel file reading for a variety of post processing techniques, are being developed in collaboration as part of the Pan-Data EU Project (www.pan-data.eu). These are particularly applicable to tomographic reconstruction and processing of non crystalline diffraction data.

  14. Solar Source Regions of Energetic 3He Emission

    NASA Astrophysics Data System (ADS)

    Mason, G. M.; Nitta, N. V.; Cohen, C. M.; Wiedenbeck, M. E.

    2012-12-01

    One of the surprising observations from the ACE mission has been the detection of energetic 3He emission occurring over multi-day periods. Previously observations of solar energetic 3He had detected short-lived "impulsive" energetic particle events which were associated with type III bursts and energetic electrons. The ACE observations were able to detect 3He at very low levels (<1% of 4He compared to ~10% in most earlier work) and this showed that the impulsive events often occurred during seemingly continuous multi-day periods of 3He emission. During solar active periods, 3He was present at 1 AU the majority of the time, giving evidence for either semi-continuous processes or else unresolved multiple small injections. The obvious injections during such periods were strongly associated with jet activity By adding STEREO and SDO observations we are seeking to extend the observational picture for these events. First, by following single 3He emitting regions from STEREO-B to ACE to STEREO-A we seek to examine for how long the 3He emission can continue, since any single spacecraft can be magnetically connected to a single region for only a few days and ACE often sees emission periods of that length. Second, by using SDO-AIA we seek to probe further the properties of the emitting regions to see if the previously reported association with jets is seen in events which we can now observe with greater resolution, sensitivity, and cadence than previously possible.

  15. Cotton harvesting emission factors based on source sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Air quality regulation across the U.S. is intensifying due to increasing public concern for environmental protection. Non-attainment status with Federal particulate matter (PM) air quality standards has forced air pollution regulators in some states to focus emission reduction efforts on previously ...

  16. Cotton harvesting emission factors based on source sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton producers in some states across the US cotton belt are facing increased regulatory pressure from state air pollution regulatory agencies. This increased pressure is due in part to inaccurate emission factors for many agricultural operations and poor regional air quality. The objective of this...

  17. Biofluorescence and the Extended Red Emission in Astrophysical Sources

    NASA Astrophysics Data System (ADS)

    Hoyle, F.; Wickramasinghe, N. C.

    1996-01-01

    A broad emission band over the wavelength range ˜ 6000 7500 Å in submicron dust in the galaxy and in M82 can be explained by fluorescence phenomena in low-temperature chloroplasts and bacterial pigments. Alternative explanations do not appear to be promising.

  18. Biofluorescence and The Extended Red Emission in Astrophysical Sources

    NASA Astrophysics Data System (ADS)

    Hoyle, F.; Wickramasinghe, N. C.

    A broad emission band over the wavelength range ~ 6000-7500 Å in submicron dust in the galaxy and in M82 can be explained by fluorescence phenomena in low-temperature chloroplasts and bacterial pigments. Alternative explanations do not appear to be promising.

  19. 40 CFR Table 1 to Subpart Nnnnnn... - HAP Emissions Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Chromium Compounds Pt. 63, Subpt. NNNNNN, Table 1 Table 1 to Subpart NNNNNN of Part 63—HAP Emissions.... Secondary rotary kiln used to recycle and refine residues containing chromium compounds. e. Residue dryer... roasting kiln. g. Quench tanks. 5. Chromium hydrate production a. Furnace used to produce chromium...

  20. 40 CFR Table 1 to Subpart Nnnnnn... - HAP Emissions Sources

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Chromium Compounds Pt. 63, Subpt. NNNNNN, Table 1 Table 1 to Subpart NNNNNN of Part 63—HAP Emissions.... Secondary rotary kiln used to recycle and refine residues containing chromium compounds. e. Residue dryer... roasting kiln. g. Quench tanks. 5. Chromium hydrate production a. Furnace used to produce chromium...

  1. 40 CFR Table 1 to Subpart Nnnnnn... - HAP Emissions Sources

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Chromium Compounds Pt. 63, Subpt. NNNNNN, Table 1 Table 1 to Subpart NNNNNN of Part 63—HAP Emissions.... Secondary rotary kiln used to recycle and refine residues containing chromium compounds. e. Residue dryer... roasting kiln. g. Quench tanks. 5. Chromium hydrate production a. Furnace used to produce chromium...

  2. 40 CFR Table 1 to Subpart Nnnnnn... - HAP Emissions Sources

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Chromium Compounds Pt. 63, Subpt. NNNNNN, Table 1 Table 1 to Subpart NNNNNN of Part 63—HAP Emissions.... Secondary rotary kiln used to recycle and refine residues containing chromium compounds. e. Residue dryer... roasting kiln. g. Quench tanks. 5. Chromium hydrate production a. Furnace used to produce chromium...

  3. 40 CFR Table 1 to Subpart Nnnnnn... - HAP Emissions Sources

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Chromium Compounds Pt. 63, Subpt. NNNNNN, Table 1 Table 1 to Subpart NNNNNN of Part 63—HAP Emissions.... Secondary rotary kiln used to recycle and refine residues containing chromium compounds. e. Residue dryer... roasting kiln. g. Quench tanks. 5. Chromium hydrate production a. Furnace used to produce chromium...

  4. Pulsar polarization: weak sources and emission features at 430 MHz

    SciTech Connect

    Rankin, J.M.; Benson, J.M.

    1981-03-01

    We have measured the Stokes parameters of the average profiles of 31 pulsars at 430 MHz. The three pulsars in our sample with interpulse emission (0823+26, 0950+08, and 1929+10) have measurable linear polarization angles. In particular, PSR 0950+08 exhibits a polarization angle signature that rotates smoothly and continuously through 180/sup 0/ across the interpulse-- main pulse waveform. Of the remaining 28 pulsars, 17 have simple profile shapes and 11 have double or complex profiles. The highest levels of linear polarization (60% to 83%) are found in four pulsars with simple profiles. The remaining 24 objects have linear polarizations more or less evenly distributed between 0% and 45%, and show no correlation of linear emission with pulse shape. Switching between dominant linear emission modes is revealed through sudden 90/sup 0/ shifts in the linear polarization angle, usually at the leading and/or trailing edges of the profiles. Interference between orthogonal emission states apparently causes much of the linear depolarization in this sample of objects. We further measure levels of circular polarization between 0% and 25% in these objects. Approximately one-half of the objects have circular levels less than approx.10%. The circular polarization fractions appear to be independent of both pulse shape and linear polarization level.

  5. Characterization of Acoustic Emission Source to Identify Fracture in Concrete

    DTIC Science & Technology

    1993-04-01

    Hardy, "An Approach to Acoustic Emission Signal Analysis," Materials Evaluation, 35, 1977 , pp. 100-106. [5] Hsu, N.N. and F.R. Breckenridge...Measurements," Journal of Applied Mechanics, 53, 1986, pp. 61-68. [17] Mindess , S., "The Fracture Process Zone in Concrete," Toughening Mechanisms in

  6. Biofluorescence and the Extended Red Emission in Astrophysical Sources

    NASA Astrophysics Data System (ADS)

    Hoyle, F.; Wickramasinghe, N. C.

    A broad emission band over the wavelength range ~6000-7500 Å in submicron dust in the galaxy and in M82 can be explained by fluorescence phenomena in low-temperature chloroplasts and bacterial pigments. Alternative explanations do not appear to be promising.

  7. Passive emission colorimetric sensor (PECS) for measuring emission rates of formaldehyde based on an enzymatic reaction and reflectance photometry.

    PubMed

    Shinohara, Naohide; Kajiwara, Tomohisa; Ohnishi, Masato; Kodama, Kenichi; Yanagisawa, Yukio

    2008-06-15

    A coin-sized passive emission colorimetric sensor (PECS) based on an enzymatic reaction and a portable reflectance photometry device were developed to determine the emission rates of formaldehyde from building materials and other materials found indoors in only 30 minutes on-site. The color change of the PECS linearly correlated to the concentration of formaldehyde aqueous solutions up to 28 microg/mL. The correlation between the emission rates measured by using the PECS and those measured by using a desiccator method or by using a chamber method was fitted with a linear function and a power function, and the determination coefficients were more than 0.98. The reproducible results indicate that the emission rates could be obtained with the correlation equations from the data measured by using the PECS and the portable reflectance photometry device. Limits of detection (LODs) were 0.051 mg/L for the desiccator method and 3.1 microg/m2/h for the chamber method. Thus, it was confirmed that the emission rates of formaldehyde from the building materials classified as F four-star (< 0.3 mg/L (desiccator method) or < 5.0 microg/m2/h (chamber method)), based on Japanese Industrial Standards (JIS), could be measured with the PECS. The measurement with PECS was confirmed to be precise (RSD < 10%). Other chemicals emitted from indoor materials, such as methanol, ethanol, acetone, toluene, and xylene, interfered little with the measurement of formaldehyde emission rates by using the PECS.

  8. Long-term variation of OH peak emission altitude and volume emission rate over Indian low latitudes

    NASA Astrophysics Data System (ADS)

    Sivakandan, M.; Ramkumar, T. K.; Taori, A.; Rao, Venkateshwara; Niranjan, K.

    2016-02-01

    Using 13 (April 2002-December 2014) years of Sounding of the Atmosphere using Broadband Emission Radiometry (SABER/TIMED) 1.6 μm OH airglow emission data, we have studied the long-term variation of OH peak emission altitude and volume emission rate (VER) for 0-10°N latitude and 70-90°E longitude grid. We have noted that, during day time the OH peak emission altitude is varying from 80 to 87 km with mean value of 83.5 km and from 82 to 88 km with mean value of 85 km during night time. The signature of semi-annual oscillation (SAO), annual oscillation (AO) and quasi-biennial oscillation (QBO) in the OH peak emission altitude as well as the VER is evident. Our analysis reveals that the SAO and QBO signatures but not the AO signature are very strong in the equatorial region during night time. Apart from the SAO, AO and QBO signatures, the presence of oscillation related to the El Niño oscillation (ENSO) is also noted. After the removal of these oscillations, we find the evidence of the influence of solar activity and a long term trend in the OH emission layer. It is also found good correlation between the mesospheric and stratospheric variations (ECMWF data).

  9. Long-term variation of OH peak emission altitude and volume emission rate over Indian low latitudes

    NASA Astrophysics Data System (ADS)

    Sivakandan, Mani; Thokuluwa, Ramkumar; Kandula, Niranjan; Taori, Alok

    2016-07-01

    Using 13 (April 2002 -December 2014) years of Sounding of the Atmosphere using Broadband Emission Radiometry (SABER/TIMED) 1.6µm OH airglow emission data, we have studied the long-term variation of OH peak emission altitude and volume emission rate (VER) for 0-10 N latitude and 70-90 E longitude grid. We have noted that, during day time the OH peak emission altitude is varying from 80 to 87 km with mean value of 83.5 km and from 82 to 88 km with mean value of 85 km during night time. The signature of semi-annual oscillation (SAO), annual oscillation (AO) and quasi-biennial oscillation (QBO) in the OH peak emission altitude as well as the VER is evident. Our analysis reveals that the SAO and QBO signatures but not the AO signature are very strong in the equatorial region during night time. Apart from the SAO, AO and QBO signatures, the presence of oscillation related to the El Niño oscillation (ENSO) is also noted. After the removal of these oscillations, we find the evidence of the influence of solar activity and a long term trend in the OH emission layer. It is also found good correlation between the mesospheric and stratospheric variations (ECMWF data).

  10. Emissions of alkaline elements calcium, magnesium, potassium, and sodium from open sources in the contiguous United States

    SciTech Connect

    Gillette, D.A. ); Stensland, G.J.; Williams, A.L.; Barnard, W.; Gatz, D. ); Sinclair, P.C. ); Johnson, T.C. )

    1992-12-01

    Models of dust emissions by wind erosion (including winds associated with regional activity as well as dust devils) and vehicular disturbances of unpaved roads were developed, calibrated, and used to estimate alkaline dust emissions from elemental soil and road composition data. Emissions from tillage of soils were estimated form the work of previous researchers. The area of maximum dust production by all of those sources is the area of the old Dust Bowl' of the 1930s (the panhandles of Texas and Oklahoma, eastern New Mexico and Colorado, and western Kansas). The areas of maximum alkaline dust production are the arid southwest, the Dust Bowl,' and the midwestern-mideastern states from Iowa to Pennsylvania. Our calculations show that calcium is the dominant alkaline element produced by open sources' (sources too great in extent to be controlled by enclosure or ducting). Although the largest dust mass source is wind erosion (by winds associated with regional activity and convective activity), the largest producer of the alkaline component is road dust because the abundance of alkaline materials in road coverings (which include crushed limestone) is significantly higher than for soils. Comparing the above estimated sources of alkaline material with inventories of SO[sub 2] and NO[sub x] emissions by previous investigators gives the rough approximation that alkaline emission rates are of the order of the SO[sub 2] + NO[sub x] emissions in the western United States and that they are much smaller than SO[sub 2] + NO[sub x] in the eastern United States. This approximation is substantiated by data on Ca/(SO[sub 4] + NO[sub 3]) for wet deposition for National Atmospheric Deposition Program sites. 53 refs., 9 figs., 2 tabs.

  11. Do vehicular emissions dominate the source of C6-C8 aromatics in the megacity Shanghai of eastern China?

    PubMed

    Wang, Hongli; Wang, Qian; Chen, Jianmin; Chen, Changhong; Huang, Cheng; Qiao, Liping; Lou, Shengrong; Lu, Jun

    2015-01-01

    The characteristic ratios of volatile organic compounds (VOCs) to i-pentane, the indicator of vehicular emissions, were employed to apportion the vehicular and non-vehicular contributions to reactive species in urban Shanghai. Two kinds of tunnel experiments, one tunnel with more than 90% light duty gasoline vehicles and the other with more than 60% light duty diesel vehicles, were carried out to study the characteristic ratios of vehicle-related emissions from December 2009 to January 2010. Based on the experiments, the characteristic ratios of C6-C8 aromatics to i-pentane of vehicular emissions were 0.53 ± 0.08 (benzene), 0.70 ± 0.12 (toluene), 0.41 ± 0.09 (m,p-xylenes), 0.16 ± 0.04 (o-xylene), 0.023 ± 0.011 (styrene), and 0.15 ± 0.02 (ethylbenzene), respectively. The source apportionment results showed that around 23.3% of C6-C8 aromatics in urban Shanghai were from vehicular emissions, which meant that the non-vehicular emissions had more importance. These findings suggested that emission control of non-vehicular sources, i.e. industrial emissions, should also receive attention in addition to the control of vehicle-related emissions in Shanghai. The chemical removal of VOCs during the transport from emissions to the receptor site had a large impact on the apportionment results. Generally, the overestimation of vehicular contributions would occur when the VOC reaction rate constant with OH radicals (kOH) was larger than that of the vehicular indicator, while for species with smaller kOH than the vehicular indicator, the vehicular contribution would be underestimated by the method of characteristic ratios.

  12. Collection and evaluation of modal traffic data for determination of vehicle emission rates under certain driving conditions. Research report

    SciTech Connect

    Yu, L.

    1997-09-01

    This report presents a research effort for collecting the on-road vehicle emission data, developing the ONROAD emission estimation model and evaluating existing emission estimation models including the emission factor models MOBILE and EMFAC. The on-road emission data were collected from highway locations in Houston using a Remote Emission Sensor (RES) called Smog Dog, which was developed by the Santa Barbara Research Center (SBRC). The SMOG DOG is used to collect the emission concentrations of CO, HC, and NO{sub x}, as well as to simultaneously record a vehicle`s instantaneous speed value and acceleration/deceleration rates while its emission is detected. During the emission data collection, the ambient temperature and humidity were periodically recorded. The collected emission data are used to develop the ONROAD emission estimation model, which consists of a series of emission estimation equations. In these emission estimation equations, the emission rates are made functions of a vehicle`s instantaneous speed, acceleration/deceleration rate, ambient temperature and humidity. The emission factors that are derived from MOBILE and EMFAC are compared with the collected on-road emission data by emulating the standard FTP driving cycles using the ONROAD emission rates. Efforts are also made to compare the emission estimates in traffic simulation models with the on-road emission data. It is found that traffic simulation models considerably underestimate the on-road emissions, and thus these models are not recommended for use in performing any field vehicle emission analysis.

  13. Collection and evaluation of modal traffic data for determination of vehicle emission rates under certain driving conditions. Final report

    SciTech Connect

    Yu, L.

    1997-08-01

    This report presents a research effort for collecting the on-road vehicle emission data, developing the ONROAD emission estimation model and evaluating existing emission estimation models including the emission factor models MOBILE and EMFAC. The on-road emission data were collected from highway locations in Houston using a Remote Emission Sensor (RES) called Smog Dog, which was developed by the Santa Barbara Research Center (SBRC). The SMOG DOG is used to collect the emission concentrations of CO, HC, and NO{sub x}, as well as to simultaneously record a vehicle`s instantaneous speed value and acceleration/deceleration rates while its emission is detected. During the emission data collection, the ambient temperature and humidity were periodically recorded. The collected emission data are used to develop the ONROAD emission estimation model, which consists of a series of emission estimation equations. In these emission estimation equations, the emission rates are made functions of a vehicle`s instantaneous speed, acceleration/deceleration rate, ambient temperature and humidity. The emission factors that are derived from MOBILE and EMFAC are compared with the collected on-road emission data by emulating the standard FTP driving cycles using the ONROAD emission rates. Efforts are also made to compare the emission estimates in traffic simulation models with the on-road emission data. It is found that traffic simulation models considerably underestimate the on-road emissions, and thus these models are not recommended for use in performing any field vehicle emission analysis.

  14. Sources of CO emissions in an HCCI engine: A numerical analysis

    SciTech Connect

    Bhave, Amit; Kraft, Markus; Montorsi, Luca; Mauss, Fabian

    2006-02-01

    Factors influencing a reliable prediction of CO emissions in a homogeneous charge compression ignition (HCCI) engine are investigated using an improved probability density function (PDF)-based engine cycle model. A previously validated PDF-based stochastic reactor model is utilized to identify critical sources of CO emissions numerically. The full cycle model includes detailed chemical kinetics, accounts for the inhomogeneities in temperature and composition, and has been demonstrated to provide sufficiently reliable predictions of the combustion and engine parameters and emissions.

  15. Quantifying natural source mercury emissions from the Ivanhoe Mining District, north-central Nevada, USA

    NASA Astrophysics Data System (ADS)

    Engle, Mark A.; Gustin, Mae Sexauer; Zhang, Hong

    In order to assess the importance of mercury emissions from naturally enriched sources relative to anthropogenic point sources, data must be collected that characterizes mercury emissions from representative areas and quantifies the influence of various environmental parameters that control emissions. With this information, we will be able to scale up natural source emissions to regional areas. In this study in situ mercury emission measurements were used, along with data from laboratory studies and statistical analysis, to scale up mercury emissions for the naturally enriched Ivanhoe Mining District, Nevada. Results from stepwise multi-variate regression analysis indicated that lithology, soil mercury concentration, and distance from the nearest fault were the most important factors controlling mercury flux. Field and lab experiments demonstrated that light and precipitation enhanced mercury emissions from alluvium with background mercury concentrations. Diel mercury emissions followed a Gaussian distribution. The Gaussian distribution was used to calculate an average daily emission for each lithologic unit, which were then used to calculate an average flux for the entire area of 17.1 ng Hg m -2 h -1. An annual emission of ˜8.7×10 4 g of mercury to the atmosphere was calculated for the 586 km 2 area. The bulk of the Hg released into the atmosphere from the district (˜89%) is from naturally enriched non-point sources and ˜11% is emitted from areas of anthropogenic disturbance where mercury was mined. Mercury emissions from this area exceed the natural emission factor applied to mercury rich belts of the world (1.5 ng m -2 h -1) by an order of magnitude.

  16. Experimental Development of Low-emittance Field-emission Electron Sources

    SciTech Connect

    Lueangaranwong, A.; Buzzard, C.; Divan, R.; Korampally, V.; Piot, P.

    2016-10-10

    Field emission electron sources are capable of extreme brightness when excited by static or time-dependent electro- magnetic fields. We are currently developing a cathode test stand operating in DC mode with possibility to trigger the emission using ultra-short (~ 100-fs) laser pulses. This contribution describes the status of an experiment to investigate field-emission using cathodes under development at NIU in collaboration with the Argonne’s Center for Nanoscale Materials.

  17. July 2010: Call for Information on GHG Emissions Associated with Bioenegy and Other Biogenic Sources

    EPA Pesticide Factsheets

    Data about biogenic sources of carbon dioxide, technical comments on accounting for biogenic CO2, and comments on developing an approach for such emissions under the Prevention of Significant Deterioration and Title V Programs under the Clean Air Act.

  18. Municipal Solid Waste Landfill New Source Performance Standards (NSPS) and Emission Guidelines (EG) -- Questions and Answers

    EPA Pesticide Factsheets

    This November 1998 document of questions and answers are provided as a guide for those subject to the new source performance standards (NSPS) or emission guidelines (EG), as well as those implementing the NSPS or EG.

  19. Comparing two micrometeorological techniques for estimating trace gas emissions from distributed sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring trace gas emission from distributed sources such as treatment lagoons, treatment wetlands, land spread of manure, and feedlots requires micrometeorological methods. In this study, we tested the accuracy of two relatively new micrometeorological techniques, vertical radial plume mapping (VR...

  20. Chemical composition of emissions from urban sources of fine organic aerosol

    SciTech Connect

    Hildemann, L.M.; Markowski, G.R.; Cass, G.R. )

    1991-04-01

    A dilution source sampling system was used to collect primary fine aerosol emissions from important sources of urban organic aerosol, including a boiler burning No. 2 fuel oil, a home fireplace, a fleet of catalyst-equipped and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations. Alternative dilution sampling techniques were used to collect emissions from cigarette smoking and a roofing tar pot, and grab sample techniques were employed to characterize paved road dust, brake lining wear, and vegetative detritus. Organic aerosol constituted the majority of the fine aerosol mass emitted from many of the sources tested. Fine primary organic aerosol emissions within the heavily urbanized western portion of the Los Angeles Basin were determined to total 29.8 metric ton/day. Over 40% of these organic aerosol emissions are from anthropogenic pollution sources that are expected to emit contemporary (nonfossil) aerosol carbon, in good agreement with the available ambient monitoring data.

  1. Acidic and total primary sulfates: development of emission factors for major stationary combustion sources

    SciTech Connect

    Goklamy, I.M.

    1984-02-01

    This paper develops 'best estimates' of emission factors for major sources of acidic and total primary sulphates for use in the compilation of emission inventories for the eastern US, which may, in turn, be used for modelling acidic or sulphate deposition. The authors conclude that much of the existing data on primary sulphates from stationary combustion sources are probably significantly biased upward and, therefore, inappropriate for the derivation of emission factors. Existing estimates of primary sulphate emissions for these source categories are probably substantially inflated. It also concludes that for most source categories, very little confidence can be attached to the best estimates because of the paucity of data obtained from measurement techniques which are likely to be free of systematic bias.

  2. Impact of various operating modes on performance and emission parameters of small heat source

    NASA Astrophysics Data System (ADS)

    Vician, Peter; Holubčík, Michal; Palacka, Matej; Jandačka, Jozef

    2016-06-01

    Thesis deals with the measurement of performance and emission parameters of small heat source for combustion of biomass in each of its operating modes. As the heat source was used pellet boiler with an output of 18 kW. The work includes design of experimental device for measuring the impact of changes in air supply and method for controlling the power and emission parameters of heat sources for combustion of woody biomass. The work describes the main factors that affect the combustion process and analyze the measurements of emissions at the heat source. The results of experiment demonstrate the values of performance and emissions parameters for the different operating modes of the boiler, which serve as a decisive factor in choosing the appropriate mode.

  3. Incorporating Voluntary Mobile Source Emission Reduction Programs in State Implementation Plans (SIPs)

    EPA Pesticide Factsheets

    This EPA memorandum provides guidance and sets forth policy and interpretation regarding the granting of explicit State Implementation Plan (SIP) credit for Voluntary Mobile Source Emission Reduction Programs (VMEPs) under section 110 of the Clean Air Act.

  4. 77 FR 41146 - Delegation of National Emission Standards for Hazardous Air Pollutants for Source Categories...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-12

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 Delegation of National Emission Standards for Hazardous Air Pollutants for Source... delegation of specific national emission standards for hazardous air pollutants (NESHAP) to the Gila...

  5. NATIONAL- AND STATE-LEVEL EMISSIONS ESTIMATES OF RADIATIVELY IMPORTANT TRACE GASES (RITGS) FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    The report documents the development of national- and state- level emissions estimates of radiatively important trace gases (RlTGs). Emissions estimates are presented for the principal anthropogenic sources of carbon dioxide (CO2), methane (CH4), chlorofluorocarbons (CFCs), and o...

  6. 78 FR 24073 - Reconsideration of Certain New Source Issues: National Emission Standards for Hazardous Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... referred to as the Mercury and Air Toxics Standards (MATS) NESHAP, and the New Source Performance Standards... ), lead (Pb), and selenium emission limits for all new coal-fired EGUs; the mercury (Hg) emission limit... EGUs Filterable particulate Hydrogen chloride, lb/ Subcategory matter, lb/MWh MWh Mercury, lb/GWh...

  7. Simulation of rail yard emissions transport to the near-source environment

    EPA Science Inventory

    Rail yards are critical nodes in the freight transportation network and locations of clustered emission sources. When people reside in close proximity to an active rail yard, the near-field effect of rail yard emissions is of concern. Field characterization of near-rail yard ai...

  8. Emission of volatile organic compounds from silage: compounds, sources, and implications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silage, fermented cattle feed, has recently been identified as a significant source of volatile organic compounds (VOCs) emitted to the atmosphere. A small number of studies have measured VOC emission from silage, but not enough is known about the processes involved to accurately quantify emission r...

  9. Source Emission Test of Gas Turbine Engine Test Facility

    DTIC Science & Technology

    1990-04-01

    emission testing be conducted in accordance with Appendix A and B to Title 40, Code of Federal Regulations, Part 60 (40 CFR 60). Determination of gas...recovery, calculations and quality assurance were done in accordance with the methods and procedures outlined in 40 CFR 60 and 87. Five sampling...hook probe nozzle, heated inconel probe, heated glass filter, impingers and a pumping and metering device. The nozzle was sized prior to each stack test

  10. Measuring trace gas emission from multi-distributed sources using vertical radial plume mapping (VRPM) and backward Lagrangian stochastic (bLS) techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two micrometeorological techniques for measuring trace gas emission rates from distributed area sources were evaluated using a variety of synthetic area sources. The accuracy of the vertical radial plume mapping (VRPM) and the backward Lagrangian (bLS) techniques with an open-path optical spectrosco...

  11. 40 CFR 63.5986 - What emission limits must I meet for tire cord production affected sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... tire cord production affected sources? 63.5986 Section 63.5986 Protection of Environment ENVIRONMENTAL... POLLUTANTS FOR SOURCE CATEGORIES National Emissions Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources § 63.5986 What emission limits must...

  12. 40 CFR 63.5987 - What are my alternatives for meeting the emission limits for tire cord production affected sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the emission limits for tire cord production affected sources? 63.5987 Section 63.5987 Protection of... Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Cord Production Affected Sources § 63.5987 What are my alternatives for meeting the emission limits for tire cord production affected sources?...

  13. Plasma emission spectroscopy for operating and developing the Spallation Neutron Source (SNS) H{sup −} ion sources

    SciTech Connect

    Han, B. X. Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Stockli, M. P.

    2014-02-15

    A RF-driven, Cs-enhanced H{sup −} ion source feeds the SNS accelerator with a high current (typically >50 mA), ∼1.0 ms pulsed beam at 60 Hz. To achieve the persistent high current beam for several weeks long service cycles, each newly installed ion source undergoes a rigorous conditioning and cesiation processes. Plasma conditioning outgases the system and sputter-cleans the ion conversion surfaces. A cesiation process immediately following the plasma conditioning releases Cs to provide coverage on the ion conversion surfaces. The effectiveness of the ion source conditioning and cesiation is monitored with plasma emission spectroscopy using a high-sensitivity optical spectrometer. Plasma emission spectroscopy is also used to provide a means for diagnosing and confirming a failure of the insulating coating of the ion source RF antenna which is immersed in the plasma. Emissions of composition elements of the antenna coating material, Na emission being the most significant, drastically elevate to signal a failure when it happens. Plasma spectra of the developmental ion source with an AlN (aluminum nitrite) chamber and an external RF antenna are also briefly discussed.

  14. Comparison of atmospheric stability methods for calculating ammonia and methane emission rates with WindTrax

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inverse dispersion models are useful tools for estimating emissions from animal feeding operations, waste storage ponds, and manure application fields. Atmospheric stability is an important input parameter to such models. The objective of this study was to compare emission rates calculated with a ba...

  15. Estimation of dairy particulate matter emission rates by lidar and inverse modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Particulate matter (PM) emissions from agricultural operations are an important issue for air quality and human health and a topic of interest to government regulators. PM emission rates from a dairy in the San Joaquin Valley of California were investigated during June 2008. The facility had 1,885 t...

  16. Determination of Lowest Achievable Emission Rate for Coors Container Corporation

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  17. Vehicle Emissions as an Important Urban Ammonia Source in the United States and China.

    PubMed

    Sun, Kang; Tao, Lei; Miller, David J; Pan, Da; Golston, Levi M; Zondlo, Mark A; Griffin, Robert J; Wallace, H W; Leong, Yu Jun; Yang, M Melissa; Zhang, Yan; Mauzerall, Denise L; Zhu, Tong

    2017-02-21

    Ammoniated aerosols are important for urban air quality, but emissions of the key precursor NH3 are not well quantified. Mobile laboratory observations are used to characterize fleet-integrated NH3 emissions in six cities in the U.S. and China. Vehicle NH3:CO2 emission ratios in the U.S. are similar between cities (0.33-0.40 ppbv/ppmv, 15% uncertainty) despite differences in fleet composition, climate, and fuel composition. While Beijing, China has a comparable emission ratio (0.36 ppbv/ppmv) to the U.S. cities, less developed Chinese cities show higher emission ratios (0.44 and 0.55 ppbv/ppmv). If the vehicle CO2 inventories are accurate, NH3 emissions from U.S. vehicles (0.26 ± 0.07 Tg/yr) are more than twice those of the National Emission Inventory (0.12 Tg/yr), while Chinese NH3 vehicle emissions (0.09 ± 0.02 Tg/yr) are similar to a bottom-up inventory. Vehicle NH3 emissions are greater than agricultural emissions in counties containing near half of the U.S. population and require reconsideration in urban air quality models due to their colocation with other aerosol precursors and the uncertainties regarding NH3 losses from upwind agricultural sources. Ammonia emissions in developing cities are especially important because of their high emission ratios and rapid motorizations.

  18. Calculations on decay rates of various proton emissions

    NASA Astrophysics Data System (ADS)

    Qian, Yibin; Ren, Zhongzhou

    2016-03-01

    Proton radioactivity of neutron-deficient nuclei around the dripline has been systematically studied within the deformed density-dependent model. The crucial proton-nucleus potential is constructed via the single-folding integral of the density distribution of daughter nuclei and the effective M3Y nucleon-nucleon interaction or the proton-proton Coulomb interaction. After the decay width is obtained by the modified two-potential approach, the final decay half-lives can be achieved by involving the spectroscopic factors from the relativistic mean-field (RMF) theory combined with the BCS method. Moreover, a simple formula along with only one adjusted parameter is tentatively proposed to evaluate the half-lives of proton emitters, where the introduction of nuclear deformation is somewhat discussed as well. It is found that the calculated results are in satisfactory agreement with the experimental values and consistent with other theoretical studies, indicating that the present approach can be applied to the case of proton emission. Predictions on half-lives are made for possible proton emitters, which may be useful for future experiments.

  19. Odour emission inventory of German wastewater treatment plants--odour flow rates and odour emission capacity.

    PubMed

    Frechen, F-B

    2004-01-01

    Wastewater Treatment plants can cause odour emissions that may lead to significant odour annoyance in their vicinity. Thus, over the past 20 years, several measurements were taken of the odour emissions that occur at WWTPs of different sizes, treatment technology, plant design and under different operating conditions. The specific aspects of odour sampling and measurement have to be considered. I presented some of the results of my odour emission measurements 11 years ago. However, it is now necessary to update the figures by evaluating newer measurement results obtained from measurements taken from 1994 to 2003. These are presented in this paper. Also, the paper highlights the odour emission capacity (OEC) measurement technique which characterises liquids and can be used to assess the results achieved by different types of treatment in the liquid phase, e.g. in a sewerage system. In addition, the OEC is a suitable parameter to set standards for the odorant content of industrial wastewaters that are discharged into the publicly owned sewerage system.

  20. FIELD MEASUREMENT OF GREENHOUSE GAS EMISSION RATES AND DEVELOPMENT OF EMISSION FACTORS FOR WASTEWATER TREATMENT

    EPA Science Inventory

    The report gives results of field testing to develop more reliable green house gas (GHG) emission estimates for Wastewater treatment (WWT) lagoons. (NOTE: Estimates are available for the amount of methane (CH4) emitted from certain types of waste facilities, but there is not adeq...

  1. Ground-based measurements of the emission rate and composition of gases from the Holuhraun eruption

    NASA Astrophysics Data System (ADS)

    Pfeffer, Melissa A.; Stefánsdóttir, Gerður; Bergsson, Baldur; Barsotti, Sara; Galle, Bo; Conde, Vladimir; Donovan, Amy; Aiuppa, Alessandro; Burton, Mike; Keller, Nicole S.; Askew, Robert A.; Ilyinskaya, Evgenia; La Spina, Alessandro; Sigurðardóttir, Guðmunda M.; Jónasdóttir, Elín B.; Snorrason, Árni; Stefánsson, Andri; Tsanev, Vitchko

    2015-04-01

    The ongoing fissure eruption at Holuhraun is distinguished by high concentrations of gases being released both from the vent(s) where lava is being extruded and from the cooling lava. The conditions for making ground-based measurements of the gases are particularly challenging: remote location, optically dense plume with high SO2 column amounts, low UV intensity, frequent clouds and precipitation, an extensive and hot lava field, and ramparts around the main vent. Three scanning DOASes capable of streaming data in almost real-time have been installed less than 15 km from the fissure. As of writing, there are two scanning DOASes operating while one unrecoverable instrument has been trapped by the lava. Traverses with a car-mounted DOAS are made along the ring road down-wind from the eruption when conditions are favorable. The SO2 emission rate is greater in the long-range traverses than from the near-source DOAS measurements. The data is being examined so that the uncertainty in the DOAS measurements can be constrained. Preliminary SO2 emission rates for the first month and a half of the eruption are ~400 kg/s with some days greater than 1000 kg/s. Plume composition measurements were made by FTIR, MultiGAS, DOAS and filter pack during multiple campaigns in the first two months of the eruption. The FTIR measurements indicated a significantly drier plume than the MultiGAS measurements. The CO2/SO2 ratio measured by MultiGAS and FTIR agree very well. Mobile DOAS traverses indicate that 80-90 % of the SO2 emissions came from the main vent with the remainder being released by the cooling lava. FTIR measured higher HCl/SO2 ratios from the cooling lava than from the main vent. The last campaign that successfully collected data (in October) showed with both FTIR and MultiGAS a drop in CO2/SO2. Since then, there have been no successful campaign measurements. Further ground-based measurements to determine the relative contribution of the lava field to the total emissions and

  2. High resolution carbon dioxide emission gridded data for China derived from point sources.

    PubMed

    Wang, Jinnan; Cai, Bofeng; Zhang, Lixiao; Cao, Dong; Liu, Lancui; Zhou, Ying; Zhang, Zhansheng; Xue, Wenbo

    2014-06-17

    A high spatial resolution carbon dioxide (CO2) emission map of China is proving to be essential for China's carbon cycle research and carbon reduction strategies given the current low quality of CO2 emission data and the inconsistencies in data quality between different regions. Ten km resolution CO2 emission gridded data has been built up for China based on point emission sources and other supporting data. The predominance of emissions from industrial point sources (84% of total emissions) in China supports the use of bottom-up methodology. The resultant emission map is informative and proved to be more spatially accurate than the EDGAR data. Spatial distribution of CO2 emissions in China is highly unbalanced and has positive spatial autocorrelation. The spatial pattern is mainly influenced by key cities and key regions, i.e., the Jing-Jin-Ji region, the Yangtze River delta region, and the Pearl River delta region. The emission map indicated that the supervision of 1% of total land could enable the management of about 70% of emissions in China.

  3. Nitrogen source effects on soil nitrous oxide emissions from strip-till corn.

    PubMed

    Halvorson, Ardell D; Del Grosso, Stephen J; Jantalia, Claudia Pozzi

    2011-01-01

    Nitrogen (N) application to crops generally results in increased nitrous oxide (NO) emissions. Commercially available, enhanced-efficiency N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated strip-till (ST) corn ( L.) production system. Enhanced-efficiency N fertilizers evaluated were a controlled-release, polymer-coated urea (ESN), stabilized urea, and UAN products containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus), and UAN containing a slow-release N source (Nfusion). Each N source was surface-band applied (202 kg N ha) at corn emergence and watered into the soil the next day. A subsurface-band ESN treatment was included. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. All N sources had significantly lower growing season NO emissions than granular urea, with UAN+AgrotainPlus and UAN+Nfusion having lower emissions than UAN. Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Loss of NO-N per kilogram of N applied was <0.8% for all N sources. Corn grain yields were not different among N sources but greater than treatments with no N applied. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in strip-till, irrigated corn in semiarid areas.

  4. [Compositions of organic acids in PM10 emission sources in Xiamen urban atmosphere].

    PubMed

    Yang, Bing-Yu; Huang, Xing-Xing; Zheng, An; Liu, Bi-Lian; Wu, Shui-Ping

    2013-01-01

    The possible organic acid emission sources in PM10 in Xiamen urban atmosphere such as cooking, biomass burning, vehicle exhaust and soil/dust were obtained using a re-suspension test chamber. A total of 15 organic acids including dicarboxylic acids, fatty acids and aromatic acids were determined using GC/MS after derivatization with BF3/n-butanol. The results showed that the highest total concentration of 15 organic acids (53%) was found in cooking emission and the average concentration of the sum of linoleic acid and oleic acid was 24% +/- 14%. However, oxalic acid was the most abundant species followed by phthalic acid in gasoline vehicle exhaust. The ratios of adipic to azelaic acid in gasoline combustion emissions were significantly higher than those in other emission sources, which can be used to qualitatively differentiate anthropogenic and biological source of dicarboxylic acids in atmospheric samples. The ratios of malonic to succinic acid in source emissions (except gasoline generator emissions) were lower (0.07-0.44) than ambient PM10 samples (0.61-3.93), which can be used to qualitatively differentiate the primary source and the secondary source of dicarboxylic acids in urban PM10.

  5. Volatile Organic Compound Concentrations and Emission Rates in New Manufactured and Site-Built Houses

    SciTech Connect

    Armin Rudd

    2008-10-30

    This study was conducted with the primary objective of characterizing and comparing the airborne concentrations and the emission rates of total VOCs and selected individual VOCs, including formaldehyde, among a limited number of new manufactured and site-built houses.

  6. Nonlocal effects: relevance for the spontaneous emission rates of quantum emitters coupled to plasmonic structures.

    PubMed

    Filter, Robert; Bösel, Christoph; Toscano, Giuseppe; Lederer, Falk; Rockstuhl, Carsten

    2014-11-01

    The spontaneous emission rate of dipole emitters close to plasmonic dimers are theoretically studied within a nonlocal hydrodynamic model. A nonlocal model has to be used since quantum emitters in the immediate environment of a metallic nanoparticle probe its electronic structure. Compared to local calculations, the emission rate is significantly reduced. The influence is mostly pronounced if the emitter is located close to sharp edges. We suggest to use quantum emitters to test nonlocal effects in experimentally feasible configurations.

  7. Does nitrogen fertilizer application rate to corn affect nitrous oxide emissions from the rotated soybean crop?

    PubMed

    Iqbal, Javed; Mitchell, David C; Barker, Daniel W; Miguez, Fernando; Sawyer, John E; Pantoja, Jose; Castellano, Michael J

    2015-05-01

    Little information exists on the potential for N fertilizer application to corn ( L.) to affect NO emissions during subsequent unfertilized crops in a rotation. To determine if N fertilizer application to corn affects NO emissions during subsequent crops in rotation, we measured NO emissions for 3 yr (2011-2013) in an Iowa, corn-soybean [ (L.) Merr.] rotation with three N fertilizer rates applied to corn (0 kg N ha, the recommended rate of 135 kg N ha, and a high rate of 225 kg N ha); soybean received no N fertilizer. We further investigated the potential for a winter cereal rye ( L.) cover crop to interact with N fertilizer rate to affect NO emissions from both crops. The cover crop did not consistently affect NO emissions. Across all years and irrespective of cover crop, N fertilizer application above the recommended rate resulted in a 16% increase in mean NO flux rate during the corn phase of the rotation. In 2 of the 3 yr, N fertilizer application to corn (0-225 kg N ha) did not affect mean NO flux rates from the subsequent unfertilized soybean crop. However, in 1 yr after a drought, mean NO flux rates from the soybean crops that received 135 and 225 kg N ha N application in the corn year were 35 and 70% higher than those from the soybean crop that received no N application in the corn year. Our results are consistent with previous studies demonstrating that cover crop effects on NO emissions are not easily generalizable. When N fertilizer affects NO emissions during a subsequent unfertilized crop, it will be important to determine if total fertilizer-induced NO emissions are altered or only spread across a greater period of time.

  8. Are diffuse sources responsible for the ARCADE excess emission?

    NASA Astrophysics Data System (ADS)

    Norris, Ray; Wall, Jasper; Mao, Minnie; Condon, Jim; Seymour, Nick; Vernstrom, Tessa

    2013-10-01

    We propose to observe a patch of sky at 2.6 GHz at low resolution to try to identify the origin of the anomalous excess in the sky background temperature obtained with the ARCADE2 experiment. The proposed observation will obtain a significant detection if the excess is due to a diffuse component, such as that predicted from dark matter annihilation. We propose to conduct this experiment in the ATLAS-ELAIS S1 field, where we already have excellent high-resolution data to subtract the compact sources. We successfully proposed and observed this in 2012APRS, but the result was marred by the difficulty of correctly subtracting the compact sources. Based on our learning from this experience, we believe we can now redesign the observation which will either detect the alleged diffuse sources or else rule them out to a very stringent limit.

  9. Atmospheric cycles of nitrogen oxides and ammonia. [source strengths and destruction rates

    NASA Technical Reports Server (NTRS)

    Bottger, A.; Ehhalt, D. H.; Gravenhorst, G.

    1981-01-01

    The atmospheric cycles of nitrogenous trace compounds for the Northern and Southern Hemispheres are discussed. Source strengths and destruction rates for the nitrogen oxides: NO, NO2 and HNO3 -(NOX) and ammonia (NH3) are given as a function of latitude over continents and oceans. The global amounts of NOX-N and NH3-N produced annually in the period 1950 to 1975 (34 + 5 x one trillion g NOx-N/yr and 29 + or - 6 x one trillion g NH3-N/yr) are much less than previously assumed. Globally, natural and anthropogenic emissions are of similar magnitude. The NOx emission from anthropogenic sources is 1.5 times that from natural processes in the Northern Hemisphere, whereas in the Southern Hemisphere, it is a factor of 3 or 4 less. More than 80% of atmospheric ammonia seems to be derived from excrements of domestic animals, mostly by bulk deposition: 24 + or - 9 x one trillion g NO3 -N/yr and 21 + or - 9 x one trillion g NH4+-N/yr. Another fraction may be removed by absorption on vegetation and soils.

  10. Tropical Lake as a Source Ofgreenhouse Gas Emissions

    NASA Astrophysics Data System (ADS)

    dos Santos, M. A.; Amorim, M. A.; Marcelino, A. A.; dos Santos, E. O.; Bezerra, C. S.

    2013-12-01

    Tropical lakes, just like other water systems, present permanent exchanges of trace gases with the atmosphere. Environmental factors, connected with seasonal climate variations in the regions where they are located, have great influence on the variability of these gas exchanges. At Lagoa de Cima (Brazil), the object of this study, it was observed that in dry periods there is greater absorption of CO2 than in the other seasons. In the case of CH4 the opposite occurs: there is great emission in the dry period. In the rainy period, there is a total inversion of the previous pattern, that is, greater absorption of CH4 and greater emission of CO2. Based on correlation with data relating to the speciation of allochthonous carbon (POC, DOC, DIC) and physicochemical parameters, situations based on the seasonal periods, i.e. dry, rainy and transitional - including therefore the influence of these factors - were studied and analyzed. It was observed that the inflow of organic matter brought by tributaries, and the surface outflow resulting from rainfall, constitute the greatest factors influencing the modulation of the main components that effect the exchanges of the gases studied.

  11. Control of mercury emissions from stationary coal combustion sources in China: Current status and recommendations.

    PubMed

    Hu, Yuanan; Cheng, Hefa

    2016-11-01

    Coal burning in power plants and industrial boilers is the largest combustion source of mercury emissions in China. Together, power plants and industrial boilers emit around 250 tonnes of mercury each year, or around half of atmospheric mercury emissions from anthropogenic sources in the country. Power plants in China are generally equipped with multi-pollutant control technologies, which offer the co-benefit of mercury removal, while mercury-specific control technologies have been installed in some facilities. In contrast, most industrial boilers have only basic or no flue gas cleaning. A combination of measures, including energy conservation, coal switching and blending, reducing the mercury contents of coals through washing, combustion controls, and flue gas cleaning, can be used to reduce mercury emissions from these stationary combustion sources. More stringent emission standards for the major air pollutants from coal-fired power plants and industrial boiler, along with standards for the previously unregulated mercury, were implemented recently, which is expected to bring significant reduction in their mercury emissions through the necessary upgrades of multi-pollutant and mercury-specific control technologies. Meanwhile, strong monitoring capacity and strict enforcement are necessary to ensure that the combustion sources operate in compliance with the new emission standards and achieve significant reduction in the emissions of mercury and other air pollutants.

  12. Estimating dispersed and point source emissions of methane in East Anglia: results and implications

    NASA Astrophysics Data System (ADS)

    Harris, Neil; Connors, Sarah; Hancock, Ben; Jones, Pip; Murphy, Jonathan; Riddick, Stuart; Robinson, Andrew; Skelton, Robert; Manning, Alistair; Forster, Grant; Oram, David; O'Doherty, Simon; Young, Dickon; Stavert, Ann; Fisher, Rebecca; Lowry, David; Nisbet, Euan; Zazzeri, Guilia; Allen, Grant; Pitt, Joseph

    2016-04-01

    We have been investigating ways to estimate dispersed and point source emissions of methane. To do so we have used continuous measurements from a small network of instruments at 4 sites across East Anglia since 2012. These long-term series have been supplemented by measurements taken in focussed studies at landfills, which are important point sources of methane, and by measurements of the 13C:12C ratio in methane to provide additional information about its sources. These measurements have been analysed using the NAME InTEM inversion model to provide county-level emissions (~30 km x ~30 km) in East Anglia. A case study near a landfill just north of Cambridge was also analysed using a Gaussian plume model and the Windtrax dispersion model. The resulting emission estimates from the three techniques are consistent within the uncertainties, despite the different spatial scales being considered. A seasonal cycle in emissions from the landfill (identified by the isotopic measurements) is observed with higher emissions in winter than summer. This would be expected from consideration of the likely activity of methanogenic bacteria in the landfill, but is not currently represented in emission inventories such as the UK National Atmospheric Emissions Inventory. The possibility of assessing North Sea gas field emissions using ground-based measurements will also be discussed.

  13. Estimating methane emissions from biological and fossil-fuel sources in the San Francisco Bay Area

    NASA Astrophysics Data System (ADS)

    Jeong, Seongeun; Cui, Xinguang; Blake, Donald R.; Miller, Ben; Montzka, Stephen A.; Andrews, Arlyn; Guha, Abhinav; Martien, Philip; Bambha, Ray P.; LaFranchi, Brian; Michelsen, Hope A.; Clements, Craig B.; Glaize, Pierre; Fischer, Marc L.

    2017-01-01

    We present the first sector-specific analysis of methane (CH4) emissions from the San Francisco Bay Area (SFBA) using CH4 and volatile organic compound (VOC) measurements from six sites during September - December 2015. We apply a hierarchical Bayesian inversion to separate the biological from fossil-fuel (natural gas and petroleum) sources using the measurements of CH4 and selected VOCs, a source-specific 1 km CH4 emission model, and an atmospheric transport model. We estimate that SFBA CH4 emissions are 166-289 Gg CH4/yr (at 95% confidence), 1.3-2.3 times higher than a recent inventory with much of the underestimation from landfill. Including the VOCs, 82 ± 27% of total posterior median CH4 emissions are biological and 17 ± 3% fossil fuel, where landfill and natural gas dominate the biological and fossil-fuel CH4 of prior emissions, respectively.

  14. A method to estimate emission rates from industrial stacks based on neural networks.

    PubMed

    Olcese, Luis E; Toselli, Beatriz M

    2004-11-01

    This paper presents a technique based on artificial neural networks (ANN) to estimate pollutant rates of emission from industrial stacks, on the basis of pollutant concentrations measured on the ground. The ANN is trained on data generated by the ISCST3 model, widely accepted for evaluation of dispersion of primary pollutants as a part of an environmental impact study. Simulations using theoretical values and comparison with field data are done, obtaining good results in both cases at predicting emission rates. The application of this technique would allow the local environment authority to control emissions from industrial plants without need of performing direct measurements inside the plant.

  15. Locating and estimating air emissions from sources of perchloroethylene and trichloroethylene. Final report

    SciTech Connect

    Most, C.C.

    1989-08-01

    To assist groups interested in inventorying air emissions of various potentially toxic substances, EPA is preparing a series of documents to compile available information on sources and emissions of these substances. This document deals specifically with perchloroethylene and trichloroethylene. Its intended audience includes Federal, State, and local air-pollution personnel and others in locating potential emitters of perchloroethylene and trichloroethylene and in making gross estimates of air emissions therefrom. The document presents information on the types of sources that may emit perchloroethylene and trichloroethylene, process variations and release points that may be expected within these sources, and available emissions information indicating the potential for trichloroethylene and perchloroethylene releases into the air from each operation.

  16. New emission deterioration rates for gasoline cars - Results from long-term measurements

    NASA Astrophysics Data System (ADS)

    Borken-Kleefeld, Jens; Chen, Yuche

    2015-01-01

    Vehicle emission control systems have been found to degrade with use resulting in increasing emission rates with vehicle age. Standard European data for deterioration factors have only been based on a sample of vehicles with limited high mileage ranges, with only few Euro 3 and Euro 4 vehicles, and on laboratory tests only. Here we present deterioration rates derived from more than 110‧000 records collected over the past thirteen years from on-road emission remote sensing in Zurich/Switzerland. Deterioration rates for hot NOx and CO emissions of older gasoline vehicles are much lower than assumed so far, but significantly higher for Euro 3 and Euro 4 cars. There is no evidence of high emitters but equipment gradually degrades across the fleet. Deterioration rates do not seem to depend on engine load. Routine idle emission tests have not resulted in measurable emission reductions of the inspected vehicles. National emission inventories should be updated in the light of this new data.

  17. 40 CFR 63.843 - Emission limits for existing sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standards for minimum exhaust rates as published by the American Conference of Governmental Industrial Hygienists in Chapters 3 and 5 of “Industrial Ventilation: A Handbook of Recommended Practice”...

  18. 40 CFR 63.843 - Emission limits for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... standards for minimum exhaust rates as published by the American Conference of Governmental Industrial Hygienists in Chapters 3 and 5 of “Industrial Ventilation: A Handbook of Recommended Practice”...

  19. Characteristics and reactivity of volatile organic compounds from non-coal emission sources in China

    NASA Astrophysics Data System (ADS)

    He, Qiusheng; Yan, Yulong; Li, Hongyan; Zhang, Yiqiang; Chen, Laiguo; Wang, Yuhang

    2015-08-01

    Volatile organic compounds (VOCs) were sampled from non-coal emission sources including fuel refueling, solvent use, industrial and commercial activities in China, and 62 target species were determined by gas chromatography-mass selective detector (GC-MSD). Based on the results, source profiles were developed and discussed from the aspects of composition characteristics, potential tracers, BTEX (benzene, toluene, ethylbenzene and xylene) diagnostic ratios and chemical reactivity. Compared with vehicle exhausts and liquid fuels, the major components in refueling emissions of liquefied petroleum gas (LPG), gasoline and diesel were alkenes and alkanes. Oppositely, aromatics were the most abundant group in emissions from auto-painting, book binding and plastic producing. Three groups contributed nearly equally in printing and commercial cooking emissions. Acetone in medical producing, chloroform and tetrachloroethylene in wet- and dry-cleaning, as well as TEX in plastic producing etc. were good tracers for the respective sources. BTEX ratios showed that some but not all VOCs sources could be distinguished by B/T, B/E and B/X ratios, while T/E, T/X and E/X ratios were not suitable as diagnostic indicators of different sources. The following reactivity analysis indicated that emissions from gasoline refueling, commercial cooking, auto painting and plastic producing had high atmospheric reactivity, and should be controlled emphatically to prevent ozone pollution, especially when there were large amounts of emissions for them.

  20. Studies of HT and HTO Behavior in the Vicinity of Long-Term Emission Source: Model - Experiment Intercomparison

    SciTech Connect

    Golubev, A. V.; Aleinikov, A. Y.; Golubeva, V. N.; Khabibulin, M. M.; Glagolev, M. V.; Misatyuk, S. E.; Mavrin, S. V.; Belot, Y. A.; Raskob, W.; Tate, P. J.

    2003-02-24

    There are presented in the research results of HT and HTO deposition and the model of HT (HTO) atmosphere concentration in the vicinity of a long-term HT and HTO emission source. Scavenging of HTO by precipitations was studied in 6 field experiments. The site of the scavenging experiments was around a 30 m emission source. The sampling arcs were chosen at 150-300 m from the base of the source to minimize dry deposition on the precipitation collectors. Data of the scavenging experiments are presented. Kinetics of HT deposition to soil through its oxidation has been studied in laboratory conditions. The activity of HTO converted in the soil sample during a certain period of time was used to determine the oxidation rate. This rate varies, depending on the catalytic and/or biological activity of the soil material. Theoretical considerations have shown that the deposition rate can be expressed by the effective rate of oxidation, which formally corresponds to the first-order HT oxidation. HT deposition rates are reported. The model, used for assessments, takes into account atmospheric dispersion, deposition and reemission. The model of HTO wet deposition is taken into account kinetics of HTO exchange between vapor and liquid phase with parameters such as rain drop spectra, rain intensity, condensation-evaporation on drop's interface. Gauss type formulae for continuous emission source is used to calculate HTO atmospheric concentration. Meteorological data are used as input parameters for modeling. The data presented on HT deposition to soil and HTO washout by precipitation is required for assessment of consequences of HT (HTO) release into the atmosphere.

  1. Global inventory of volatile organic compound emissions from anthropogenic sources. Final report, March 1988-September 1990

    SciTech Connect

    Watson, J.J.; Probert, J.A.; Piccot, S.D.

    1991-01-01

    The report describes a global inventory of anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds. The inventory, one input to atmospheric chemistry models required to estimate the global atmospheric concentration of ozone, is part of an assessment of the potential environmental impacts associated with global climate change. Study results show total global anthropogenic emissions of about 121 million short tons of VOCs per year. The U.S. is the largest emitter with 21% of the total. Globally, fuelwood combustion and savanna burning are the largest sources, together accounting for over 35% of global VOC emissions. The approach used to develop the inventory involved: (1) identifying the major anthropogenic sources of VOC emissions in the U.S. and grouping them into categories; (2) developing emission factors by dividing the U.S. emissions by the amount of production or consumption of the related commodity in the U.S.; (3) multiplying the U.S. emission factors by production/consumption statistics for other countries to yield global VOC emission estimates; and (4) geographically distributing the emissions.

  2. Development of molecular marker source profiles for emissions from on-road gasoline and diesel vehicle fleets.

    PubMed

    Lough, Glynis C; Christensen, Charles G; Schauer, James J; Tortorelli, James; Mani, Erin; Lawson, Douglas R; Clark, Nigel N; Gabele, Peter A

    2007-10-01

    As part of the Gasoline/Diesel PM Split Study, relatively large fleets of gasoline vehicles and diesel vehicles were tested on a chassis dynamometer to develop chemical source profiles for source attribution of atmospheric particulate matter in California's South Coast Air Basin. Gasoline vehicles were tested in cold-start and warm-start conditions, and diesel vehicles were tested through several driving cycles. Tailpipe emissions of particulate matter were analyzed for organic tracer compounds, including hopanes, steranes, and polycyclic aromatic hydrocarbons. Large intervehicle variation was seen in emission rate and composition, and results were averaged to examine the impacts of vehicle ages, weight classes, and driving cycles on the variation. Average profiles, weighted by mass emission rate, had much lower uncertainty than that associated with intervehicle variation. Mass emission rates and elemental carbon/organic carbon (EC/OC) ratios for gasoline vehicle age classes were influenced most by use of cold-start or warm-start driving cycle (factor of 2-7). Individual smoker vehicles had a large range of mass and EC/OC (factors of 40 and 625, respectively). Gasoline vehicle age averages, data on vehicle ages and miles traveled in the area, and several assumptions about smoker contributions were used to create emissions profiles representative of on-road vehicle fleets in the Los Angeles area in 2001. In the representative gasoline fleet profiles, variation was further reduced, with cold-start or warm-start and the representation of smoker vehicles making a difference of approximately a factor of two in mass emission rate and EC/OC. Diesel vehicle profiles were created on the basis of vehicle age, weight class, and driving cycle. Mass emission rate and EC/OC for diesel averages were influenced by vehicle age (factor of 2-5), weight class (factor of 2-7), and driving cycle (factor of 10-20). Absolute and relative emissions of molecular marker compounds showed

  3. Bidirectional exchange of biogenic volatiles with vegetation: emission sources, reactions, breakdown and deposition

    PubMed Central

    Niinemets, Ülo; Fares, Silvano; Harley, Peter; Jardine, Kolby J.

    2014-01-01

    Biogenic volatile organic compound (BVOC) emissions are widely modeled as inputs to atmospheric chemistry simulations. However, BVOC may interact with cellular structures and neighboring leaves in a complex manner during volatile diffusion from the sites of release to leaf boundary layer and during turbulent transport to the atmospheric boundary layer. Furthermore, recent observations demonstrate that the BVOC emissions are bidirectional, and uptake and deposition of BVOC and their oxidation products are the rule rather than the exception. This review summarizes current knowledge of within-leaf reactions of synthesized volatiles with reactive oxygen species (ROS), uptake, deposition and storage of volatiles and their oxidation products as driven by adsorption on leaf surface and solubilization and enzymatic detoxification inside leaves. The available evidence indicates that due to reactions with ROS and enzymatic metabolism, the BVOC gross production rates are much larger than previously thought. The degree to which volatiles react within leaves and can be potentially taken up by vegetation depends on compound reactivity, physicochemical characteristics, as well as their participation in leaf metabolism. We argue that future models should be based on the concept of bidirectional BVOC exchange and consider modification of BVOC sink/source strengths by within-leaf metabolism and storage. PMID:24635661

  4. Mercury in soil near a long-term air emission source in southeastern Idaho

    USGS Publications Warehouse

    Abbott, M.L.; Susong, D.D.; Olson, M.; Krabbenhoft, D.P.

    2003-01-01

    At the Idaho National Engineering and Environmental Laboratory in southeastern Idaho, a 500??C fluidized bed calciner was intermittently operated for 37 years, with measured Hg emission rates of 9-11 g/h. Surface soil was sampled at 57 locations around the facility to determine the spatial distribution of Hg fallout and surface Hg variability, and to predict the total residual Hg mass in the soil from historical emissions. Measured soil concentrations were slightly higher (p<0.05) within 5 km of the source but were overall very low (15-20 ng/g) compared to background Hg levels published for similar soils in the USA (50-70 ng/g). Concentrations decreased 4%/cm with depth and were found to be twice as high under shrubs and in depressions. Mass balance calculations accounted for only 2.5-20% of the estimated total Hg emitted over the 37-year calciner operating history. These results suggest that much of the Hg deposited from calciner operations may have been reduced in the soil and re-emitted as Hg(0) to the global atmospheric pool.

  5. Patch antenna microcavity terahertz sources with enhanced emission

    NASA Astrophysics Data System (ADS)

    Madéo, J.; Todorov, Y.; Gilman, A.; Frucci, G.; Li, L. H.; Davies, A. G.; Linfield, E. H.; Sirtori, C.; Dani, K. M.

    2016-10-01

    We study the emission properties of an electroluminescent THz frequency quantum cascade structure embedded in an array of patch antenna double-metal microcavities. We show that high photon extraction efficiencies can be obtained by adjusting the active region thickness and array periodicity as well as high Purcell factors (up to 65), leading to an enhanced overall emitted power. Up to a 44-fold increase in power is experimentally observed in comparison with a reference device processed in conventional mesa geometry. Estimation of the Purcell factors using electromagnetic simulations and the theoretical extraction efficiency are in agreement with the observed power enhancement and show that, in these microcavities, the overall enhancement solely depends on the square of the total quality factor.

  6. Nitrogen Source Effects on Soil Nitrous Oxide Emissions from No-Till Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of N fertilizer source on soil nitrous oxide (N2O) emissions from a no-till, irrigated continuous corn field was evaluated near Fort Collins, CO in 2009 and 2010. Five N sources (urea, ESN, SuperU, UAN, UAN+AgrotainPlus) were surface band applied at 202 kg N/ha at corn emergence, includi...

  7. Nitrogen Source Effects on Nitrous Oxide Emissions from a Strip-Tilled Corn Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of N source on nitrous oxide (N2O) emissions from a strip-till, irrigated continuous corn field was evaluated near Fort Collins, CO. Six N fertilizer sources (urea, ESN, SuperU, UAN, UAN+AgrotainPlus, UAN+Nfusion) were surface band applied at 202 kg N/ha near the corn row at corn emerge...

  8. 75 FR 77799 - National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-14

    ... AGENCY 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing... Hazardous Air Pollutants for Chemical Manufacturing Area Sources. Among the provisions that EPA is... Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources on October 29, 2009. 40...

  9. ASSESSING THE PERFORMANCE OF FULL-SCALE ENVIRONMENTAL CHAMBERS USING AN INDEPENDENTLY MEASURED EMISSION SOURCE

    EPA Science Inventory

    The paper discusses the assessment of the performance of full-scale environmental chambers using an independently measured emission source. To assess the overall performance of an environmental test chamber, it is necessary to subject the chamber to a test with a reference sourc...

  10. Sulfur dioxide emission rates from Kīlauea Volcano, Hawai‘i, 2007–2010

    USGS Publications Warehouse

    Elias, T.; Sutton, A.J.

    2012-01-01

    Kīlauea Volcano has one of the longest running volcanic sulfur dioxide (SO2) emission rate databases on record. Sulfur dioxide emission rates from Kīlauea Volcano were first measured by Stoiber and Malone (1975) and have been measured on a regular basis since 1979 (Elias and Sutton, 2007, and references within). Compilations of SO2 emission-rate and wind-vector data from 1979 through 2006 are available on the USGS Web site (Elias and others, 1998; Elias and Sutton, 2002; Elias and Sutton, 2007). This report updates the database, documents the changes in data collection and processing methods, and highlights how SO2 emissions have varied with eruptive activity at Kīlauea Volcano for the interval 2007–2010.

  11. Source characteristics and locations of hectometric radio emissions from the northern Jovian hemisphere

    NASA Technical Reports Server (NTRS)

    Reiner, M. J.; Fainberg, J.; Stone, R. G.

    1993-01-01

    Northern Jovian hectometric (HOM) radio emissions, detected from high Jovian latitudes by the Unified Radio and Plasma Wave experiment on the Ulysses spacecraft, were observed at all Jovian longitudes. This emission was observed to be predominantly right-hand circularly polarized, but some left-hand circular polarization was observed implying the presence of O mode emissions from the northern Jovian hemisphere. Intense HOM emissions, with well-defined directions and polarizations, were often confined to similar longitudinal regions where intense HOM emissions were previously observed at low latitudes. The present analysis confirms that these northern HOM sources lie in the Jovian polar regions on magnetic field lines that pass through the Io plasma torus. The observations may be consistent with emission from either a filled cone beam or a longitudinal distribution of thin hollow cones.

  12. Mobile source hazardous air pollutant emissions in the Seattle-Tacoma urban area. Report for February 1993-November 1994

    SciTech Connect

    Mangino, J.; Jones, J.W.

    1994-12-31

    This paper describes mobile source hazardous air pollutant (HAP) emissions in the Seattle-Tacoma, Washington, urban area. Included in this inventory are mobile source emissions from both on-road (e.g., highway vehicles) and non-road (e.g., agricultural equipment) mobile sources. These mobile source emission estimates, summarized in this paper, were developed based on volatile organic compound (VOC) emissions and activity level data from the Seattle-Tacoma 1990 base year State Implementation Plan (SIP) emission inventory. The contribution of mobile source HAP emissions was compared to that of stationary area sources in the Seattle-Tacoma area. Mobile sources contributed about 83% of the benzene, 74% of the formaldehyde, and 88% of the 1,3-butadiene emissions.

  13. Mobile source emission control cost-effectiveness: Issues, uncertainties, and results

    SciTech Connect

    Wang, M.Q.

    1994-12-01

    Emissions from mobile sources undoubtedly contribute to US urban air pollution problems. Consequently, mobile source control measures, ranging from vehicle emission standards to reducing vehicle travel, have been adopted or proposed to help attain air quality standards. To rank various mobile source control measures, various government agencies and private organizations calculate cost-effectiveness in dollars per ton of emissions reduced. Arguments for or against certain control measures are often made on the basis of the calculated cost-effectiveness. Yet, different studies may yield significantly different cost-effectiveness results, because of the various methodologies used and assumptions regarding the values of costs and emission reductions. Because of the methodological differences, the cost-effectiveness results may not be comparable between studies. Use of incomparable cost-effectiveness results may result in adoption of ineffective control measures. This paper first discusses some important methodological issues involved in cost-effectiveness calculation for mobile sources and proposes appropriate, systematic methods for dealing with these issues. Various studies have been completed recently to evaluate the cost-effectiveness of mobile source emission control measures. These studies resulted in wide variations in the cost-effectiveness for same control measures. Methodological assumptions used in each study are presented and, based on the proposed methods for cost-effectiveness calculation, adjustments are applied to the original estimates in each study to correct inappropriate methodological assumptions and to make the studies comparable. Finally, mobile source control measures are ranked on the basis of the adjusted cost-effectiveness estimates.

  14. Enhanced Atlantic sea-level rise relative to the Pacific under high carbon emission rates

    NASA Astrophysics Data System (ADS)

    Krasting, J. P.; Dunne, J. P.; Stouffer, R. J.; Hallberg, R. W.

    2016-03-01

    Thermal expansion of the ocean in response to warming is an important component of historical sea-level rise. Observational studies show that the Atlantic and Southern oceans are warming faster than the Pacific Ocean. Here we present simulations using a numerical atmospheric-ocean general circulation model with an interactive carbon cycle to evaluate the impact of carbon emission rates, ranging from 2 to 25 GtC yr-1, on basin-scale ocean heat uptake and sea level. For simulations with emission rates greater than 5 GtC yr-1, sea-level rise is larger in the Atlantic than Pacific Ocean on centennial timescales. This basin-scale asymmetry is related to the shorter flushing timescales and weakening of the overturning circulation in the Atlantic. These factors lead to warmer Atlantic interior waters and greater thermal expansion. In contrast, low emission rates of 2 and 3 GtC yr-1 will cause relatively larger sea-level rise in the Pacific on millennial timescales. For a given level of cumulative emissions, sea-level rise is largest at low emission rates. We conclude that Atlantic coastal areas may be particularly vulnerable to near-future sea-level rise from present-day high greenhouse gas emission rates.

  15. 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).

  16. Novel techniques for characterization of hydrocarbon emission sources in the Barnett Shale

    NASA Astrophysics Data System (ADS)

    Nathan, Brian Joseph

    Changes in ambient atmospheric hydrocarbon concentrations can have both short-term and long-term effects on the atmosphere and on human health. Thus, accurate characterization of emissions sources is critically important. The recent boom in shale gas production has led to an increase in hydrocarbon emissions from associated processes, though the exact extent is uncertain. As an original quantification technique, a model airplane equipped with a specially-designed, open-path methane sensor was flown multiple times over a natural gas compressor station in the Barnett Shale in October 2013. A linear optimization was introduced to a standard Gaussian plume model in an effort to determine the most probable emission rate coming from the station. This is shown to be a suitable approach given an ideal source with a single, central plume. Separately, an analysis was performed to characterize the nonmethane hydrocarbons in the Barnett during the same period. Starting with ambient hourly concentration measurements of forty-six hydrocarbon species, Lagrangian air parcel trajectories were implemented in a meteorological model to extend the resolution of these measurements and achieve domain-fillings of the region for the period of interest. A self-organizing map (a type of unsupervised classification) was then utilized to reduce the dimensionality of the total multivariate set of grids into characteristic one-dimensional signatures. By also introducing a self-organizing map classification of the contemporary wind measurements, the spatial hydrocarbon characterizations are analyzed for periods with similar wind conditions. The accuracy of the classification is verified through assessment of observed spatial mixing ratio enhancements of key species, through site-comparisons with a related long-term study, and through a random forest analysis (an ensemble learning method of supervised classification) to determine the most important species for defining key classes. The hydrocarbon

  17. Influence of electrode separation and gas curtain on extreme ultraviolet emission of a gas jet z-pinch source

    NASA Astrophysics Data System (ADS)

    Mohanty, S. R.; Sakamoto, T.; Kobayashi, Y.; Izuka, N.; Kishi, N.; Song, I.; Watanabe, M.; Kawamura, T.; Okino, A.; Horioka, K.; Hotta, E.

    2006-07-01

    Extreme ultraviolet (EUV) emission from a gas jet z-pinch source has been examined by employing a photodiode and pinhole camera. Visible images of the pinched plasma have been also recorded. A current pulse of 10kA is used to heat the gas jet, which emits radiation around 13.5nm. Experimental parameters such as electrode separation and gas flow rate are varied to optimize EUV emission. The maximum EUV energy is obtained for 12mm electrode separation and 20Torr xenon pressure and it is estimated to 10.95mJ/sr per 2% bandwidth per pulse. The presence of gas curtain improves EUV emission by 30%.

  18. Estimating source regions of European emissions of trace gases from observations at Mace Head

    NASA Astrophysics Data System (ADS)

    Ryall, D. B.; Derwent, R. G.; Manning, A. J.; Simmonds, P. G.; O'Doherty, S.

    A technique is described for identifying probable source locations for a range of greenhouse and ozone-depleting trace gases from the long-term measurements made at Mace Head, Ireland. The Met. Office's dispersion model NAME is used to predict concentrations at Mace Head from all possible sources in Europe, then source regions identified as those which consistently lead to elevated concentrations at Mace Head. Estimates of European emissions and their distribution are presented for a number of trace gases for the period 1995-1998. Estimated emission patterns are realistic, given the nature and varied applications of the species considered. The results indicate that whilst there are limitations, useful information about source distribution can be extracted from continuous measurements at a remote site. It is probable that much improved estimates could be derived if observations were available from a number of sites. The ability to assess emissions has obvious implications in monitoring compliance with internationally agreed quota and protocols.

  19. Short-chain oxygenated VOCs: Emission and uptake by plants and atmospheric sources, sinks, and concentrations

    NASA Astrophysics Data System (ADS)

    Seco, Roger; Peñuelas, Josep; Filella, Iolanda

    Emissions of volatile organic compounds (VOCs) have multiple atmospheric implications and play many roles in plant physiology and ecology. Among these VOCs, growing interest is being devoted to a group of short-chain oxygenated VOCs (oxVOCs). Technology improvements such as proton transfer reaction-mass spectrometry are facilitating the study of these hydrocarbons and new data regarding these compounds is continuously appearing. Here we review current knowledge of the emissions of these oxVOCs by plants and the factors that control them, and also provide an overview of sources, sinks, and concentrations found in the atmosphere. The oxVOCs reviewed here are formic and acetic acids, acetone, formaldehyde, acetaldehyde, methanol, and ethanol. In general, because of their water solubility (low gas-liquid partitioning coefficient), the plant-atmosphere exchange is stomatal-dependent, although it can also take place via the cuticle. This exchange is also determined by atmospheric mixing ratios. These compounds have relatively long atmospheric half-lives and reach considerable concentrations in the atmosphere in the range of ppbv. Likewise, under non-stressed conditions plants can emit all of these oxVOCs together at fluxes ranging from 0.2 up to 4.8 μg(C)g -1(leaf dry weight)h -1 and at rates that increase several-fold when under stress. Gaps in our knowledge regarding the processes involved in the synthesis, emission, uptake, and atmospheric reactivity of oxVOCs precludes the clarification of exactly what is conditioning plant-atmosphere exchange—and also when, how, and why this occurs—and these lacunae therefore warrant further research in this field.

  20. The use of satellite-measured aerosol optical depth to constrain biomass burning emissions source strength in the global model GOCART

    NASA Astrophysics Data System (ADS)

    Petrenko, Mariya; Kahn, Ralph; Chin, Mian; Soja, Amber; Kucsera, Tom; Harshvardhan, null

    2012-09-01

    Simulations of biomass burning (BB) emissions in chemistry transport models strongly depend on the inventories that define emission source location and strength. We use 13 global biomass burning emission estimates, including the widely used Global Fire Emission Database (GFED) monthly and daily versions, Fire Radiative Power (FRP)-based Quick Fire Emission Data set QFED, and 11 calculated emissions from different combinations of burned area based on the Moderate Resolution Imaging Spectroradiometer (MODIS) products, effective fuel load, and species emission factors as alternative inputs to the global Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. The resultant simulated aerosol optical depth (AOD) and its spatial distribution are compared to AOD snapshots measured by the MODIS instrument for 124 fire events occurring between 2006 and 2007. This comparison exposes the regional biases of each emission option. GOCART average fire AOD values compare best to MODIS-measured AOD when the daily GFED inventory is used as input to GOCART. Even though GFED-based emission options provide the lowest emissions in the tropics, GFED-based GOCART AOD compares best with MODIS AOD in tropical cases. Fire-counts-based emission options give the largest emission estimates in the boreal regions, and the model performs best at higher latitudes with these inputs when compared to MODIS. Comparison of total annual BB emissions by all inventories suggests that burned area estimates are usually the largest source of disagreement. It is also shown that the quantitative relationship between BB aerosol emission rate and model-simulated AOD is related to the horizontal plume dispersion, which can be approximated by the wind speed in the planetary boundary layer in most cases. Thus, given average wind speed of the smoke plume environment, MODIS-measured AOD can provide a constraint to the strength of BB sources at the level of individual plumes.

  1. Source-receptor relationships between East Asian sulfur dioxide emissions and Northern Hemisphere sulfate concentrations

    NASA Astrophysics Data System (ADS)

    Liu, J.; Mauzerall, D. L.; Horowitz, L. W.

    2008-07-01

    We analyze the effect of varying East Asian (EA) sulfur emissions on sulfate concentrations in the Northern Hemisphere, using a global coupled oxidant-aerosol model (MOZART-2). We conduct a base and five sensitivity simulations, in which sulfur emissions from each continent are tagged, to establish the source-receptor (S-R) relationship between EA sulfur emissions and sulfate concentrations over source and downwind regions. We find that from west to east across the North Pacific, EA sulfate contributes approximately 80% 20% of sulfate at the surface, but at least 50% at 500 hPa. Surface sulfate concentrations are dominated by local anthropogenic sources. Of the sulfate produced from sources other than local anthropogenic emissions (defined here as "background" sulfate), EA sources account for approximately 30% 50% (over the Western US) and 10% 20% (over the Eastern US). The surface concentrations of sulfate from EA sources over the Western US are highest in MAM (up to 0.15 μg/m3), and lowest in DJF (less than 0.06 μg/m3). Reducing EA SO2 emissions will significantly decrease the spatial extent of the EA sulfate influence (represented by the areas where at least 0.1 μg m-3 of sulfate originates from EA) over the North Pacific both at the surface and at 500 hPa in all seasons, but the extent of influence is insensitive to emission increases, particularly in DJF and JJA. We find that EA sulfate concentrations over most downwind regions respond nearly linearly to changes in EA SO2 emissions, but sulfate concentrations over the EA source region increase more slowly than SO2 emissions, particularly at the surface and in winter, due to limited availability of oxidants (in particular of H2O2, which oxidizes SO2 to sulfate in the aqueous phase). We find that similar estimates of the S-R relationship for trans-Pacific transport of EA sulfate would be obtained using either sensitivity (i.e., varying emissions from a region to examine the effects on downwind concentrations

  2. Particulate matter emission rates from beef cattle feedlots in Kansas-reverse dispersion modeling.

    PubMed

    Bonifacio, Henry F; Maghirang, Ronaldo G; Auvermann, Brent W; Razote, Edna B; Murphy, James P; Harner, Joseph P

    2012-03-01

    Open beef cattle feedlots emit various air pollutants, including particulate matter (PM) with equivalent aerodynamic diameter of 10 microm or less (PM10); however limited research has quantified PM10 emission rates from feedlots. This research was conducted to determine emission rates of PM10 from large cattle feedlots in Kansas. Concentrations of PM10 at the downwind and upwind edges of two large cattle feedlots (KS1 and KS2) in Kansas were measured with tapered element oscillating microbalance (TEOM) PM10 monitors from January 2007 to December 2008. Weather conditions at the feedlots were also monitored. From measured PM10 concentrations and weather conditions, PM10 emission rates were determined using reverse modeling with the American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model (AERMOD). The two feedlots differed significantly in median PM10 emission flux (1.60 g/m2-day for KS1 vs. 1.10 g/m2-day for KS2) but not in PM10 emission factor (27 kg/1000 head-day for KS1 and 30 kg/1000 head-day KS2). These emission factors were smaller than published U.S. Environmental Protection Agency (EPA) emission factor for cattle feedlots.

  3. Modeled and observed ozone sensitivity to mobile-source emissions in Mexico City

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Lei, W.; Molina, M. J.; Molina, L. T.

    2009-01-01

    The emission characteristics of mobile sources in the Mexico City Metropolitan Area (MCMA) have changed significantly over the past few decades in response to emission control policies, advancements in vehicle technologies and improvements in fuel quality, among others. Along with these changes, concurrent non-linear changes in photochemical levels and criteria pollutants have been observed, providing a unique opportunity to understand the effects of perturbations of mobile emission levels on the photochemistry in the region using observational and modeling approaches. The observed historical trends of ozone (O3), carbon monoxide (CO) and nitrogen oxides (NOx) suggest that ozone production in the MCMA has changed from a low to a high VOC-sensitive regime over a period of 20 years. Comparison of the historical emission trends of CO, NOx and hydrocarbons derived from mobile-source emission studies in the MCMA from 1991 to 2006 with the trends of the concentrations of CO, NOx, and the CO/NOx ratio during peak traffic hours also indicates that fuel-based fleet average emission factors have significantly decreased for CO and VOCs during this period whereas NOx emission factors do not show any strong trend, effectively reducing the ambient VOC/NOx ratio. This study presents the results of model analyses on the sensitivity of the observed ozone levels to the estimated historical changes in its precursors. The model sensitivity analyses used a well-validated base case simulation of a high pollution episode in the MCMA with the mathematical Decoupled Direct Method (DDM) and the standard Brute Force Method (BFM) in the 3-D CAMx chemical transport model. The model reproduces adequately the observed historical trends and current photochemical levels. Comparison of the BFM and the DDM sensitivity techniques indicates that the model yields ozone values that increase linearly with NOx emission reductions and decrease linearly with VOC emission reductions only up to 30% from the

  4. Modeled and observed ozone sensitivity to mobile-source emissions in Mexico City

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Lei, W. F.; Molina, M. J.; Molina, L. T.

    2008-08-01

    The emission characteristics of mobile sources in the Mexico City Metropolitan Area (MCMA) have changed significantly over the past few decades in response to emission control policies, advancements in vehicle technologies and improvements in fuel quality, among others. Along with these changes, concurrent non-linear changes in photochemical levels and criteria pollutants have been observed, providing a unique opportunity to understand the effects of perturbations of mobile emission levels on the photochemistry in the region using observational and modeling approaches. The observed historical trends of ozone (O3), carbon monoxide (CO) and nitrogen oxides (NOx) suggest that ozone production in the MCMA has changed from a low to a high VOC-sensitive regime over a period of 20 years. Comparison of the historical emission trends of CO, NOx and hydrocarbons derived from mobile-source emission studies in the MCMA from 1991 to 2006 with the trends of the concentrations of CO, NOx, and the CO/NOx ratio during peak traffic hours also indicates that fuel-based fleet average emission factors have significantly decreased for CO and VOCs during this period whereas NOx emission factors do not show any strong trend, effectively reducing the ambient VOC/NOx ratio. This study presents the results of model analyses on the sensitivity of the observed ozone levels to the estimated historical changes in its precursors. The model sensitivity analyses used a well-validated base case simulation of a high pollution episode in the MCMA with the mathematical Decoupled Direct Method (DDM) and the standard Brute Force Method (BFM) in the 3-D CAMx chemical transport model. The model reproduces adequately the observed historical trends and current photochemical levels. Comparison of the BFM and the DDM sensitivity techniques indicates that the model yields ozone values that increase linearly with NOx emission reductions and decrease linearly with VOC emission reductions only up to 30% from the

  5. BLACK Carbon Emissions from Diesel Sources in the Largest Arctic City: Case Study of Murmansk

    NASA Astrophysics Data System (ADS)

    Evans, M.; Kholod, N.; Malyshev, V.; Tretyakova, S.; Gusev, E.; Yu, S.; Barinov, A.

    2014-12-01

    Russia has very little data on its black carbon (BC) emissions. Because Russia makes up such a large share of the Arctic, understanding Russian emissions will improve our understanding of overall BC levels, BC in the Arctic and the link between BC and climate change. This paper provides a detailed, bottom-up inventory of BC emissions from diesel sources in Murmansk, Russia, along with uncertainty estimates associated with these emissions. The research team developed a detailed data collection methodology. The methodology involves assessing the vehicle fleet and activity in Murmansk using traffic, parking lot and driver surveys combined with an existing database from a vehicle inspection station and statistical data. The team also assessed the most appropriate emission factors, drawing from both Russian and international inventory methodologies. The researchers also compared fuel consumption using statistical data and bottom-up fuel calculations. They then calculated emissions for on-road transportation, off-road transportation (including mines), diesel generators, fishing and other sources. The article also provides a preliminary assessment of Russia-wide emissions of black carbon from diesel sources.

  6. Characterization of emissions sources in the California-Mexico Border Region during Cal-Mex 2010

    NASA Astrophysics Data System (ADS)

    Zavala, M. A.; Lei, W.; Li, G.; Bei, N.; Barrera, H.; Tejeda, D.; Molina, L. T.; Cal-Mex 2010 Emissions Team

    2010-12-01

    The California-Mexico border region provides an opportunity to evaluate the characteristics of the emission processes in rapidly expanding urban areas where intensive international trade and commerce activities occur. Intense anthropogenic activities, biomass burning, as well as biological and geological sources significantly contribute to high concentration levels of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides (NOx), volatile organic compounds (VOCs), air toxics, and ozone observed in the California-US Baja California-Mexico border region. The continued efforts by Mexico and US for improving and updating the emissions inventories in the sister cities of San Diego-Tijuana and Calexico-Mexicali has helped to understand the emission processes in the border region. In addition, the recent Cal-Mex 2010 field campaign included a series of measurements aimed at characterizing the emissions from major sources in the California-Mexico border region. In this work we will present our analyzes of the data obtained during Cal-Mex 2010 for the characterization of the emission sources and their use for the evaluation of the recent emissions inventories for the Mexican cities of Tijuana and Mexicali. The developed emissions inventories will be implemented in concurrent air quality modeling efforts for understanding the physical and chemical transformations of air pollutants in the California-Mexico border region and their impacts.

  7. Need for Emission Cap on Complex Netting Sources

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  8. Consideration of Fugitive Emissions in Major Source Determinations

    EPA Pesticide Factsheets

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  9. Toxicological evaluation of realistic emission source aerosols (TERESA): summary and conclusions

    PubMed Central

    Godleski, John J.; Rohr, Annette C.; Coull, Brent A.; Kang, Choong-Min; Diaz, Edgar A.; Koutrakis, Petros

    2013-01-01

    The toxicological evaluation of realistic emissions of source aerosols (TERESA) study seeks to delineate health effects of aerosols formed from emissions of particulate matter sources. This series of papers reports the findings of experiments using coal-fired power plants as the source of emissions and this paper summarizes the findings and knowledge acquired from these studies. Emissions were drawn directly from the stacks of three coal-fired power plants in the US, and photochemically aged in a mobile laboratory to simulate downwind power plant plume processing. The power plants used different sources of coal and had different emission controls. Exposure scenarios included primary particles, secondary particles and mixtures of these with common atmospheric constituents (α-pinene and ammonia). Extensive exposure characterization was carried out, and toxicological outcomes were evaluated in Sprague-Dawley rats exposed to different emission scenarios. Breathing pattern, pulmonary inflammatory responses, in vivo pulmonary and cardiac chemiluminescence and cardiac response in a model of acute myocardial infarction were assessed. The results showed no response or relatively mild responses to the inhaled aerosols studied; complex scenarios which included oxidized emissions and α-pinene to simulate biogenic secondary organic aerosol tended to induce more statistically significant responses than scenarios of oxidized and non-oxidized emissions alone. Relating adverse effects to specific components did not consistently identify a toxic constituent. These findings are consistent with most of the previously published studies using pure compounds to model secondary power plant emissions, but importantly add substantial complexity and thus have considerable merit in defining toxicological responses. PMID:21913822

  10. Application of optical emission spectroscopy for the SNS H- ion source plasma studies

    NASA Astrophysics Data System (ADS)

    Han, B. X.; Stockli, M. P.; Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.

    2015-04-01

    The SNS H- ion source is a dual-frequency RF-driven (13.56-MHz low power continuous RF superimposed by 2-MHz high power pulsed RF with ˜1.0 ms pulse length at 60 Hz), Cs-enhanced ion source. This paper discusses the applications of optical emission spectroscopy for the ion source plasma conditioning, cesiation, failure diagnostics, and studies of plasma build-up and outage issues.

  11. Source apportionment of traffic emissions of particulate matter using tunnel measurements

    NASA Astrophysics Data System (ADS)

    Lawrence, Samantha; Sokhi, Ranjeet; Ravindra, Khaiwal; Mao, Hongjun; Prain, Hunter Douglas; Bull, Ian D.

    2013-10-01

    This study aims to quantify exhaust/non-exhaust emissions and the uncertainties associated with them by combining innovative motorway tunnel sampling and source apportionment modelling. Analytical techniques ICP-AES and GC-MS were used to identify the metallic and organic composition of PM10, respectively. Good correlation was observed between Fe, Cu, Mn, Ni, Pb and Sb and change in traffic volume. The concentration of polycyclic aromatic hydrocarbons and other organics varies significantly at the entrance and exit site of the tunnel, with fluoranthene, pyrene, benzo[a]pyrene, chrysene and benzothiazole having the highest incremented concentrations. The application of Principal Component Analysis and Multiple Linear Regression Analysis helped to identify the emission sources for 82% of the total PM10 mass inside the tunnel. Identified sources include resuspension (27%), diesel exhaust emissions (21%), petrol exhaust emissions (12%), brake wear emissions (11%) and road surface wear (11%). This study shows that major health related chemical species of PM10 originate from non-exhaust sources, further signifying the need for legislation to reduce these emissions.

  12. Quantitative acoustic emission from localized sources in material fatigue processes

    NASA Astrophysics Data System (ADS)

    Shi, Zhiqiang; Jarzynski, Jacek; Jacobs, Laurence

    2000-05-01

    Fretting fatigue is the phenomenon where two contacting bodies undergoing a cyclic fatigue loading experience small amplitude oscillatory motion. Fretting fatigue is characterized by crack nucleation and the subsequent propagation of these cracks. The coupling of fatigue with fretting leads to the premature nucleation and acceleration of the early growth of fatigue cracks, resulting in a significant reduction in a structure's service life. A better understanding of the mechanics of fretting fatigue is needed to prevent and reduce the severe consequences of such damage. This research uses quantitative acoustic emission (AE) techniques to study the fretting fatigue of PH 13-8 stainless steel under different loading conditions. Specifically, this work correlates AE signals to specific fretting characteristics such as frictional force history and frictional force-displacement hysteresis loops. These results indicate a close correlation between the various stages of fretting fatigue with the frequency of AE events. For example, AE waveform characteristics (such as amplitude, energy, and frequency spectrum) enable the identification and characterization of the different stages of fatigue. As a result, it is possible to establish a relationship between AE observations and fretting crack initiation and growth.

  13. Source-receptor relationships between East Asian sulfur dioxide emissions and Northern Hemisphere sulfate concentrations

    NASA Astrophysics Data System (ADS)

    Liu, J.; Mauzerall, D. L.; Horowitz, L. W.

    2008-03-01

    We analyze the effect of varying East Asian (EA) sulfur emissions on sulfate concentrations in the Northern Hemisphere, using a global coupled oxidant-aerosol model (MOZART-2). We conduct a base and five sensitivity simulations, in which sulfur emissions from each continent are tagged, to establish the source-receptor (S-R) relationship between EA sulfur emissions and sulfate concentrations over source and downwind regions. We find that from west to east across the North Pacific, EA sulfate contributes approximately 80%-20% of sulfate at the surface, but at least 50% at 500 hPa. In addition, EA SO2 emissions account for approximately 30%-50% and 10%-20% of North American background sulfate over the western and eastern US, respectively. The contribution of EA sulfate to the western US at the surface is highest in MAM and JJA, but is lowest in DJF. Reducing EA SO2 emissions will significantly decrease the spatial extent of the EA sulfate influence over the North Pacific both at the surface and at 500 mb in all seasons, but the extent of influence is insensitive to emission increases, particularly in DJF and JJA. We find that EA sulfate concentrations over most downwind regions respond nearly linearly to changes in EA SO2 emissions, but sulfate concentrations over the EA source region increase more slowly than SO2 emissions, particularly at the surface and in winter, due to limited availability of oxidants (mostly H2O2). We find that similar estimates of the S-R relationship for trans-Pacific transport of EA sulfate would be obtained using either sensitivity or tagging techniques. Our findings suggest that future changes in EA sulfur emissions may cause little change in the sulfate induced health impact over downwind continents but SO2 emission reductions may significantly reduce the sulfate related climate cooling over the North Pacific and the United States.

  14. Atmospheric mercury emissions in Australia from anthropogenic, natural and recycled sources

    NASA Astrophysics Data System (ADS)

    Nelson, Peter F.; Morrison, Anthony L.; Malfroy, Hugh J.; Cope, Martin; Lee, Sunhee; Hibberd, Mark L.; Meyer, C. P. (Mick); McGregor, John

    2012-12-01

    The United Nations Environment Programme (UNEP) has begun a process of developing a legally binding instrument to manage emissions of mercury from anthropogenic sources. The UNEP Governing Council has concluded that there is sufficient evidence of significant global adverse impacts from mercury to warrant further international action; and that national, regional and global actions should be initiated as soon as possible to identify populations at risk and to reduce human generated releases. This paper describes the development of, and presents results from, a comprehensive, spatially and temporally resolved inventory of atmospheric mercury emissions from the Australian landmass. Results indicate that the best estimate of total anthropogenic emissions of mercury to the atmosphere in 2006 was 15 ± 5 tonnes. Three industrial sectors contribute substantially to Australian anthropogenic emissions: gold smelting (˜50%, essentially from a single site/operation), coal combustion in power plants (˜15%) and alumina production from bauxite (˜12%). A diverse range of other sectors contribute smaller proportions of the emitted mercury, but industrial emissions account for around 90% of total anthropogenic mercury emissions. The other sectors include other industrial sources (mining, smelting, and cement production) and the use of products containing mercury. It is difficult to determine historical trends in mercury emissions given the large uncertainties in the data. Estimates for natural and re-emitted emissions from soil, water, vegetation and fires are made using meteorological models, satellite observations of land cover and soil and vegetation type, fuel loading, fire scars and emission factors which account for the effects of temperature, insolation and other environmental variables. These natural and re-emitted sources comfortably exceed the anthropogenic emissions, and comprise 4-12 tonnes per year from vegetation, 70-210 tonnes per year from soils, and 21-63 tonnes

  15. Using a dispersion model to estimate emission rates of particulate matter from paved roads

    NASA Astrophysics Data System (ADS)

    Venkatram, Akula; Fitz, Dennis; Bumiller, Kurt; Du, Shuming; Boeck, Michael; Ganguly, Chandragupta

    From January 1996 to June 1997, we carried out a series of measurements to estimate emissions of PM 10 from paved roads in Riverside County, California. The program involved the measurement of upwind and downwind vertical profiles of PM 10, in addition to meteorological variables such as wind speed and vertical turbulent intensity. This information was analyzed using a new dispersion model that incorporates current understanding of micrometeorology and dispersion. The emission rate was inferred by fitting model predictions to measurements. The inferred emission factors ranged from 0.2 g VKT -1 for freeways to about 3 g VKT -1 for city roads. The uncertainty in these factors is estimated to be approximately a factor of two since the contributions of paved road PM 10 emissions to ambient concentrations were comparable to the uncertainty in the mean value of the measurement. At this stage, our best estimate of emission factor lies between 0.1 and 10 g VKT -1; there is some indication that it is about 0.1 g VKT -1 for heavily traveled freeways, and is an order of magnitude higher for older city roads. We found that measured silt loadings were poor predictors of emission factors. The measured emission factors imply that paved road emissions may contribute about 30% to the total PM 10 emissions from a high traffic area such as Los Angeles. This suggests that it is necessary to develop methods that are more reliable than the upwind-downwind concentration difference technique.

  16. Global organic carbon emissions from primary sources from 1960 to 2009

    NASA Astrophysics Data System (ADS)

    Huang, Ye; Shen, Huizhong; Chen, Yilin; Zhong, Qirui; Chen, Han; Wang, Rong; Shen, Guofeng; Liu, Junfeng; Li, Bengang; Tao, Shu

    2015-12-01

    In an attempt to reduce uncertainty, global organic carbon (OC) emissions from a total of 70 sources were compiled at 0.1° × 0.1° resolution for 2007 (PKU-OC-2007) and country scale from 1960 to 2009. The compilation took advantage of a new fuel-consumption data product (PKU-Fuel-2007) and a series of newly published emission factors (EFOC) in developing countries. The estimated OC emissions were 32.9 Tg (24.1-50.6 Tg as interquartile range), of which less than one third was anthropogenic in origin. Uncertainty resulted primarily from variations in EFOC. Asia, Africa, and South America had high emissions mainly because of residential biomass fuel burning or wildfires. Per-person OC emission in rural areas was three times that of urban areas because of the relatively high EFOC of residential solid fuels. Temporal trend of anthropogenic OC emissions depended on rural population, and was influenced primarily by residential crop residue and agricultural waste burning. Both the OC/PM2.5 ratio and emission intensity, defined as quantity of OC emissions per unit of fuel consumption for all sources, of anthropogenic OC followed a decreasing trend, indicating continuous improvement in combustion efficiency and control measures.

  17. Extraction of Emission Source Images in d+Au and

    NASA Astrophysics Data System (ADS)

    Chung, Paul

    2004-10-01

    Relativistic heavy ion collisions at RHIC, produce a fireball of nuclear matter with extremely high energy density. The dynamical evolution of this fireball is driven by such fundamental properties as the nuclear Equation of State (EOS) and possibly by a phase transition, e.g., to a Quark Gluon Plasma (QGP). Two-particle correlation studies, for various particle species,provide an important probe of the space-time extent of this fireball. In recent measurements the PHENIX collaboration has used a model-independent imaging technique proposed by Brown and Danielewicz(D.Brown and P.Danieliwicz, Phys.Rev.C 64, 014902 (2001))to extract two-particle source functions directly from Au+Au and d+Au collisions at √sNN=200 GeV. Source images obtained from these two systems for various particle species for several centality and kt selections will be presented and compared/contrasted. The implications of these results for the decay dynamics of the fireball created at RHIC will also be dicussed.

  18. COS-B gamma ray sources beyond the predicted diffuse emission

    NASA Technical Reports Server (NTRS)

    Mayer-Hasselwander, H. A.; Simpson, G.

    1990-01-01

    COS-B data were reanalyzed using for background subtraction the modeled galactic diffuse gamma-ray emission based on HI- and CO-line surveys and the gamma-ray data itself. A methodology was developed for this purpose with the following three features: automatic generation of source catalogs using correlation analysis, simulation of trials to derive significance thresholds for source detection, and bootstrap sampling to drive error boxes and confidence intervals for source parameters. The analysis shows that about half of the 2CG sources are explained by concentrations in the distribution of molecular hydrogen. Indication for a few weak new sources is also obtained.

  19. THE EFFECT OF VENTILATION ON EMISSION RATES OF WOOD FINISHING MATERIALS

    EPA Science Inventory

    The rate of emission of organic compounds from building materials varies according to: type of material, material loading (area of material/volume of room), compound emitted, temperature, humidity, and ventilation rate. For some compounds and materials (e.g., formaldehyde from pa...

  20. Legal and financial methods for reducing low emission sources: Options for incentives

    SciTech Connect

    Samitowski, W.

    1995-12-31

    There are two types of the so-called low emission sources in Cracow: over 1,000 local boiler houses and several thousand solid fuel-fired stoves. The accomplishment of each of 5 sub-projects offered under the American-Polish program entails solving the technical, financial, legal and public relations-related problems. The elimination of the low emission source requires, therefore, a joint effort of the following pairs: (a) local authorities, (b) investors, (c) owners and users of low emission sources, and (d) inhabitants involved in particular projects. The results of the studies developed by POLINVEST indicate that the accomplishment of the projects for the elimination of low emission sources will require financial incentives. Bearing in mind the today`s resources available from the community budget, this process may last as long as a dozen or so years. The task of the authorities of Cracow City is making a long-range operational strategy enabling reduction of low emission sources in Cracow.

  1. Detection of trace gas emissions from point sources using shortwave infrared imaging spectrometry

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Roberts, D. A.; Dennison, P. E.; Bradley, E. S.; Funk, C. C.

    2011-12-01

    Existing spaceborne remote sensing provides an effective means of detecting continental-scale variation in trace gas concentrations, but does not permit mapping of local emissions from point sources. Point source emissions of methane (CH4), nitrous oxide (N2O) and particulates, often associated with combustion and carbon dioxide (CO2) emissions, have significant impacts on air quality. Using Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) data and a cluster-tuned matched filter technique, we have mapped local CH4, N2O and CO2 emissions from terrestrial sources in the Los Angeles basin. CH4 anomalies were in close proximity to known and probable emission sources, including hydrocarbon storage tanks and gas flares. Multiple N2O and CH4 anomalies were detected at a wastewater treatment facility, while CH4 and CO2 anomalies were also identified at a large oil refinery. We discuss ongoing efforts to estimate CH4 concentrations using radiative transfer modeling and potential application of this technique to additional trace gasses with distinct absorption features. This method could be applied to data from existing airborne sensors and planned satellite missions like HyspIRI, thereby improving high resolution mapping of trace gasses and better constraining local sources.

  2. Control for NO(x) Emissions from Combustion Sources

    NASA Technical Reports Server (NTRS)

    PozodeFernandez, Maria E.

    2001-01-01

    The Environmental Program Office at the Kennedy Space Center is interested in finding solutions and to promote R&D that could contribute to solve the problems of air, soil and groundwater contamination. This study is undertaken as part of NASA's environmental stewardship program. The objective of this study involves the removal of nitrogen oxides from the flue gases of the boilers at KSC using hydrogen peroxide. Phases 1 and 2 of this study have shown the potential of this process to be used as an alternative to the current methods of treatment used in the power industry. This report summarizes the research done during the 10-week summer program. During this period, support has been given to implement the modifications suggested for Phase 3 of the project, which focus on oxidation reactions carried at lower to medium temperatures using UV lights as a source for the hydrogen peroxide dissociation and the effect on the NO conversion.

  3. Semiconductor light source with electrically tunable emission wavelength

    DOEpatents

    Belenky, Gregory; Bruno, John D.; Kisin, Mikhail V.; Luryi, Serge; Shterengas, Leon; Suchalkin, Sergey; Tober, Richard L.

    2011-01-25

    A semiconductor light source comprises a substrate, lower and upper claddings, a waveguide region with imbedded active area, and electrical contacts to provide voltage necessary for the wavelength tuning. The active region includes single or several heterojunction periods sandwiched between charge accumulation layers. Each of the active region periods comprises higher and lower affinity semiconductor layers with type-II band alignment. The charge carrier accumulation in the charge accumulation layers results in electric field build-up and leads to the formation of generally triangular electron and hole potential wells in the higher and lower affinity layers. Nonequillibrium carriers can be created in the active region by means of electrical injection or optical pumping. The ground state energy in the triangular wells and the radiation wavelength can be tuned by changing the voltage drop across the active region.

  4. Source apportionment vs. emission inventories of non-methane hydrocarbons (NMHC) in an urban area of the Middle East: local and global perspectives

    NASA Astrophysics Data System (ADS)

    Salameh, Thérèse; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

    2016-03-01

    We applied the positive matrix factorization model to two large data sets collected during two intensive measurement campaigns (summer 2011 and winter 2012) at a sub-urban site in Beirut, Lebanon, in order to identify NMHC (non-methane hydrocarbons) sources and quantify their contribution to ambient levels. Six factors were identified in winter and five factors in summer. PMF-resolved source profiles were consistent with source profiles established by near-field measurements. The major sources were traffic-related emissions (combustion and gasoline evaporation) in winter and in summer accounting for 51 and 74 wt %, respectively, in agreement with the national emission inventory. The gasoline evaporation related to traffic source had a significant contribution regardless of the season (22 wt % in winter and 30 wt % in summer). The NMHC emissions from road transport are estimated from observations and PMF results, and compared to local and global emission inventories. The PMF analysis finds reasonable differences on emission rates, of 20-39 % higher than the national road transport inventory. However, global inventories (ACCMIP, EDGAR, MACCity) underestimate the emissions up to a factor of 10 for the transportation sector. When combining emission inventory to our results, there is strong evidence that control measures in Lebanon should be targeted on mitigating the NMHC emissions from the traffic-related sources. From a global perspective, an assessment of VOC (volatile organic compounds) anthropogenic emission inventories for the Middle East region as a whole seems necessary as these emissions could be much higher than expected at least from the road transport sector.

  5. Emissions of CO2 and criteria air pollutants from mobile sources: Insights from integrating real-time traffic data into local air quality models

    NASA Astrophysics Data System (ADS)

    Gately, Conor; Hutyra, Lucy

    2016-04-01

    In 2013, on-road mobile sources were responsible for over 26% of U.S. fossil fuel carbon dioxide (ffCO2) emissions, and over 34% of both CO and NOx emissions. However, accurate representations of these emissions at the scale of urban areas remains a difficult challenge. Quantifying emissions at the scale of local streets and highways is critical to provide policymakers with the information needed to develop appropriate mitigation strategies and to guide research into the underlying process that drive mobile emissions. Quantification of vehicle ffCO2 emissions at high spatial and temporal resolutions requires a detailed synthesis of data on traffic activity, roadway attributes, fleet characteristics and vehicle speeds. To accurately characterize criteria air pollutant emissions, information on local meteorology is also critical, as the temperature and relative humidity can affect emissions rates of these pollutants by as much as 400%. As the health impacts of air pollutants are more severe for residents living in close proximity (<500m) to road sources, it is critical that inventories of these emissions rely on highly resolved source data to locate potential hot-spots of exposure. In this study we utilize real-time GPS estimates of vehicle speeds to estimate ffCO2 and criteria air pollutant emissions at multiple spatial and temporal scales across a large metropolitan area. We observe large variations in emissions associated with diurnal activity patterns, congestion, sporting and civic events, and weather anomalies. We discuss the advantages and challenges of using highly-resolved source data to quantify emissions at a roadway scale, and the potential of this methodology for forecasting the air quality impacts of changes in infrastructure, urban planning policies, and regional climate.

  6. Emissions of CO2 and criteria air pollutants from mobile sources: Insights from integrating real-time traffic data into local air quality models

    NASA Astrophysics Data System (ADS)

    Gately, C.; Hutyra, L.; Sue Wing, I.; Peterson, S.; Janetos, A.

    2015-12-01

    In 2013, on-road mobile sources were responsible for over 26% of U.S. fossil fuel carbon dioxide (ffCO2) emissions, and over 34% of both CO and NOx emissions. However, accurate representations of these emissions at the scale of urban areas remains a difficult challenge. Quantifying emissions at the scale of local streets and highways is critical to provide policymakers with the information needed to develop appropriate mitigation strategies and to guide research into the underlying process that drive mobile emissions. Quantification of vehicle ffCO2 emissions at high spatial and temporal resolutions requires a detailed synthesis of data on traffic activity, roadway attributes, fleet characteristics and vehicle speeds. To accurately characterize criteria air pollutant emissions, information on local meteorology is also critical, as the temperature and relative humidity can affect emissions rates of these pollutants by as much as 400%. As the health impacts of air pollutants are more severe for residents living in close proximity (<500m) to road sources, it is critical that inventories of these emissions rely on highly resolved source data to locate potential hot-spots of exposure. In this study we utilize real-time GPS estimates of vehicle speeds to estimate ffCO2 and criteria air pollutant emissions at multiple spatial and temporal scales across a large metropolitan area. We observe large variations in emissions associated with diurnal activity patterns, congestion, sporting and civic events, and weather anomalies. We discuss the advantages and challenges of using highly-resolved source data to quantify emissions at a roadway scale, and the potential of this methodology for forecasting the air quality impacts of changes in infrastructure, urban planning policies, and regional climate.

  7. Emission rates of particulate matter and elemental and organic carbon from in-use diesel engines.

    PubMed

    Shah, Sandip D; Cocker, David R; Miller, J Wayne; Norbeck, Joseph M

    2004-05-01

    Elemental carbon (EC), organic carbon (OC), and particulate matter (PM) emission rates are reported for a number of heavy heavy-duty diesel trucks (HHDDTs) and back-up generators (BUGs) operating under real-world conditions. Emission rates were determined using a unique mobile emissions laboratory (MEL) equipped with a total capture full-scale dilution tunnel connected directly to the diesel engine via a snorkel. This paper shows that PM, EC, and OC emission rates are strongly dependent on the mode of vehicle operation; highway, arterial, congested, and idling conditions were simulated by following the speed trace from the California Air Resources Board HHDDT cycle. Emission rates for BUGs are reported as a function of engine load at constant speed using the ISO 8178B Cycle D2. The EC, OC, and PM emission rates were determined to be highly variable for the HHDDTs. It was determined that the per mile emission rate of OC from a HHDDT in congested traffic is 8.1 times higher than that of an HHDDT in cruise or highway speed conditions and 1.9 times higher for EC. EC/OC ratios for BUGs (which generally operate at steady states) and HHDDTs show marked differences, indicating that the transient nature of engine operation dictates the EC/OC ratio. Overall, this research shows that the EC/OC ratio varies widely for diesel engines in trucks and BUGs and depends strongly on the operating cycle. The findings reported here have significant implications in the application of chemical mass balance modeling, diesel risk assessment, and control strategies such as the Diesel Risk Reduction Program.

  8. Ozone formation potentials of organic compounds from different emission sources in the South Coast Air Basin of California

    NASA Astrophysics Data System (ADS)

    Chen, Jianjun; Luo, Dongmin

    2012-08-01

    Different organic compounds exhibit different propensities for ozone formation. Two approaches were used to study the ozone formation potentials or source reactivities of different anthropogenic organic compounds emission categories in California's South Coast Air Basin (SoCAB). The first approach was based on the combination of total organic gases (TOG) emission speciation profiles and the maximum incremental reactivity (MIR) scale of organic species. The second approach quantified ozone impacts from different emission sources by performing 3-dimensional air quality model sensitivity analysis involving increased TOG emissions from particular sources. The source reactivities derived from these two approaches agree reasonably well for 58 anthropogenic organic compounds emission categories in the SoCAB. Both approaches identify TOG emissions from mobile sources as having the highest reactivity. Source reactivities from both approaches were also combined with TOG emissions from each source category to produce a 2005 reactivity-based anthropogenic TOG emission inventory for the SoCAB. The top five reactivity-based anthropogenic TOG emission sources in the SoCAB during 2005 were: light-duty passenger cars, off-road equipment, consumer products, light-duty trucks category 2 (i.e., 3751-5750 lb), and recreational boats. This is in contrast to the mass-based TOG emission inventory, which indicates that livestock waste and composting emission categories were two of the five largest mass-based anthropogenic TOG emission sources. The reactivity-based TOG emission inventory is an important addition to the mass-based TOG emission inventory because it represents the ozone formation potentials from emission sources and can be used to assist in determining targeted sources for developing organic compounds reduction policies.

  9. Contribution of Point Sources to the Soft Gamma-Ray Galactic Emission

    NASA Astrophysics Data System (ADS)

    Terrier, R.; Lebrun, F.; Bélanger, G.; Goldwurm, A.; Strong, A. W.; Schoenfelder, V.; Bouchet, L.; Roques, J. P.; Parmar, A.

    2004-10-01

    The nature of the soft gamma-ray (20-200 keV) Galactic emission has been a matter of debate for a long time. Previous experiments have tried to sep- arate the point source contribution from the real in- terstellar emission, but with a rather poor spatial res- olution, they concluded that the interstellar emission could be a large fraction of the total Galactic emis- sion. INTEGRAL, having both high resolution and high sensitivity, is well suited to reassess more pre- cisely this problem. Using the INTEGRAL core pro- gram Galactic Center Deep Exposure (GCDE), we estimate the contribution of detected point sources to the total Galactic flux. Key words: Interstellar emission; INTEGRAL; IBIS/ISGRI.

  10. Tradable permit system for PM(2.5) emissions from residential and industrial sources.

    PubMed

    Mardones, Cristian; Sanhueza, Leonardo

    2015-07-01

    Residential wood combustion is a significant source of air pollution in urban areas of many countries with cold weather and low cost of firewood. These conditions worsen in urban areas where atmospheric emissions from industrial activities are present. This study addresses this problem and extends the existing literature to develop an optimization model that simulates a system of tradable permits for fine particulate matter emissions, which includes different options to reduce emissions for both industrial and residential sources. Results show that replacing wood heaters in urban areas is highly desirable from an economic and environmental perspective regardless if the expenses originate from each household, public programs or emission compensation mechanisms from the industrial sector.

  11. Red Sprites as the source of ELF emission from lightning

    NASA Astrophysics Data System (ADS)

    Rai, J.

    2013-12-01

    Jagdish Rai Invertis University, NH-24, Bareilly, India and Manoj K. Paras Department of Applied Sciences, DIT University, Dehradun, India. ABSTRACT Rai (1974) discussed the possibility of upper atmospheric lightning discharges. These discharges were observed experimentally by sertman et al (1995), Lyons (1996), Stenback- Nielsen and Mc Harg (2008) and many others. Cummer et al (1998) and Cummer (2003) observed that the radiation from red sprites lie in the ELF range. From the knowledge of velocity and current expressions obtained by Paras and Rai (2011) for red sprites, authors obtained the frequency spectrum of emitted radiation. The radiation lies mainly in ELF range and peaks around 40Hz. A comparative study of radio emissions from red sprite and return stroke- lateral corona current system shows that the power radiated from the former is higher than the later. When subjected to the propagation in earth -ionosphere waveguide, authors find that the Schumann resonances are caused by red sprites and not by return strokes. References:- 1. Cummer, S.A., U.S. Inan, T.F. Bell and C.P. Barrington-Leigh, 1998, ELF radiation produced by electrical currents in sprites, Geophys. Res. Letters 25, 8. 2. Cummer, S.A. 2003, Current moment in sprite producing lightning , J. Atmos. Solar Terr. Phys., 65, 499-908. 3. Lyons W.A., 1996 Sprite observations above the U.S. high plains in relation to their parent thunderstorm systems, J. Geophys. Res. D101, 29641. 4. Paros M.K. and J. Rai, 2011 Electric and magnetic fields from return stroke- lateral corona system and red sprites J. Electromagnetic Analysis and Applications, 3. 5. Rai J., 1974 some studies on lighting, Ph.D. Thesis Banaras Hindu University, Varanasi, India. 6. Sentman D.D., E.M. Wescott, D.L. Osborne, D.L. Hampton and M.J. Heazener, 1995, Preliminary results from the sprites 94 Campaign, Red Sprites, Geophy. Res. Letters, 22, 1205. 7. Stenback- Nielson H.C. and Mc Harg M.G., 2008, High time resolution sprite imaging

  12. Model estimate of mercury emission from natural sources in East Asia

    NASA Astrophysics Data System (ADS)

    Shetty, Suraj K.; Lin, Che-Jen; Streets, David G.; Jang, Carey

    East Asia is one of the largest source regions that release mercury into the atmosphere. Although extensive studies have been devoted to estimating the anthropogenic mercury emission, little is known about mercury emission from natural sources in the region. In this study, we adapt the algorithms developed previously, coupled with detailed GIS data and satellite LAI products, to estimate mercury emission from natural sources including vegetation, soil, and water surfaces in an East Asian domain containing 164 × 97 grid cells at a spatial resolution of 36 km. Seasonal simulations were performed to project the annual emission quantity. The simulated emission shows strong diurnal and seasonal variations due to meteorology and vegetation coverage. The annual emission in the form of gaseous elemental mercury (GEM) from the domain in 2001 is estimated to be 834 Mg, with 462 Mg contributed from China. The estimated GEM emission is comparable to the reported anthropogenic emission of 575 ± 261 Mg (56% GEM, 32% reactive gaseous mercury, 12% particulate mercury; Wu, Y., Wang, S., Streets, D.G., Hao, J., Chan, M., Jiang, J., 2006. Trends in anthropogenic mercury emissions in China from 1995 to 2003. Environmental Science & Technology 40, 5312-5318) in China for the year 2001, and dominates the anthropogenic emission during the warm season. Combining the anthropogenic and natural emission estimates, the total mercury emission from China is 776-1298 Mg, with GEM being in the range of 660-1000 Mg. The latter is similar to the GEM emission quantity inferred from aircraft measurement (765 Mg; Friedli, H.R., Radke, L.F., Prescott, R., Li, P., Woo, J.-H., Carmichael, G.R., 2004. Mercury in the atmosphere around Japan, Korea and China as observed during the 2001 ACE Asia field campaign: measurements, distributions, sources, and implications. Journal of Geophysical Research 109, D19 S25) and modeling estimate (1140 Mg; Pan, L., Chai, T., Carmichael, G.R., Tang, Y., Streets, G

  13. An Acetylene Tracer-Based Approach to Quantifying Methane Emissions from Distributed Sources Using Wavelength-Scanned Cavity Ring-Down Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rella, C.; Crosson, E.; Thoma, E.; Hater, G.; Merrill, R.; Tan, S.; Green, R.

    2009-12-01

    The quantification of fugitive methane emissions from extended sources such as landfills is problematic due to the high temporal variability and spatial inhomogeneity of the emission. Additionally, the relationship between the emission rate and the gas concentration at a given location is dependent on the meteorological conditions and local topography, preventing accurate quantification of the emission rate. When the total source emission is of interest, tracer methods allow quantitative measurements to be made using a single, mobile gas analyzer located in the far field of the source (i.e., at a distance that is large compared with the size of the extended source). Making measurements in the far field enables both the extended source and the tracer to be approximated as point sources. By releasing a tracer gas at a known rate at or near the center of the extended area source, the far-field measurement of the ratio of concentrations yields the ratio of emission rates, since the effects of atmospheric dispersion are the same for both species. An ultra-sensitive, dual species gas analyzer based on wavelength scanned cavity ring-down spectroscopy has been developed to measure the concentrations of methane and acetylene with the required sensitivity and speed. Acetylene has been selected as a tracer gas due to its low concentration in the environment and the high detection sensitivity that can be achieved. We present field measurements of landfill methane plumes and overlapped acetylene plumes using this new instrument. Both mobile and fixed-point field data obtained with this analyzer are presented that demonstrate simplicity and robustness of the method. Both the strengths and the limitations of the acetylene tracer-based method are discussed.

  14. Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

    SciTech Connect

    Mazurek, M.A. ); Hildemann, L.M. . Dept. of Civil Engineering); Cass, G.R.; Rogge, W.F. . Dept. of Environmental Engineering Science); Simoneit, B.R.T. . Coll. of Oceanography)

    1990-04-01

    Extractable organic compounds having between 6 to 40 carbon atoms comprise an important mass fraction of the fine particulate matter samples from major urban emission sources. Depending on the emission source type, this solvent-soluble fraction accounts for <20% to 100% of the total organic aerosol mass, as measured by quantitative high-resolution has chromatography (HRGC) with flame ionization detection. In addition to total extract quantitation, HRGC can be applied to further analyses of the mass distributions of elutable organics present in the complex aerosol extract mixtures, thus generating profiles that serve as fingerprints'' for the sources of interest. This HRGC analytical method is applied to emission source samples that contain between 7 to 12,000 {mu}g/filter organic carbon. It is shown to be a sensitive technique for analysis of carbonaceous aerosol extract mixtures having diverse mass loadings and species distributions. This study describes the analytical chemical methods that have been applied to: the construction of chemical mass balances based on the mass of fine organic aerosol emitted for major urban sources of particulate carbon; and the generation of discrete emission source chemical profiles derived from chromatographic characteristics of the organic aerosol components. 21 refs., 1 fig., 2 tabs.

  15. Source of O mode radio emissions from the dayside of Uranus

    SciTech Connect

    Menietti, J.D.; Curran, D.B. )

    1990-09-01

    During the inbound trajectory toward Uranus the Planetary Radio Astronomy instrument on board the Voyager 2 spacecraft observed narrowband smooth (n-smooth) emission at frequencies centered near 60 kHz and O mode emission (the dayside source) in a frequency range narrowly confined around 160 kHz. By assuming empirical models of the plasma density for the dayside magnetosphere of Uranus, and by using cold plasma theory together with observational constraints, the authors have performed ray-tracing calculations to determine the source lcoation of the O mode emission. The dayside source appears to originate along magnetic field lines with a footprint near the north magnetic pole. Sources of nightside, high-frequency, broadband smooth (b-smooth) emission observed by Voyager after encounter are believed to exist near the conjugate footprint of these same field lines. This would indicate that the particle population supplying the free energy source has energies at least as high as a few keV and the density in the source region satisfies the condition 0.3 < f{sub p}/f{sub ce} < 1.0 where f{sub p} and f{sub ce} are the electron plasma frequency and gyrofrequency, respectively.

  16. Source characterization of major emission sources in the imperial and Mexicali Valleys along the US/Mexico border.

    PubMed

    Watson, J G; Chow, J C

    2001-08-10

    Chemical profiles for particle emissions are needed for source apportionment studies using the chemical mass balance (CMB) receptor model. Source measurements of geological sources, motor vehicle exhaust, vegetative burning (e.g. asparagus, field burning, charbroil cooking), and industrial sources (e.g. oil-fueled glass plant, manure-fueled power plants) were acquired as part of the Imperial/Mexicali Valley Cross Border PM10 Transport Study in 1992. Six different source sampling techniques (i.e. hot- and diluted-exhaust sampling, ground-based source sampling, particle sweeping/grab sampling, vacuum sampling, and laboratory resuspension sampling) were applied to acquire filter samples of PM 2.5 and PM10 (particulate matter with aerodynamic diameters < 2.5 and 10 microm, respectively). Filter samples were analyzed for mass by gravimetry, elements (Na to U) by X-ray fluorescence, anions (Cl(-), NO3(-), SO4(=)) by ion chromatography, ammonium (NH4(+)) by automated colorimetry, soluble sodium (Na+) and potassium (K+) by atomic absorption spectrophotometry, and organic and elemental carbon (OC, EC) by thermal/optical reflectance. Concentration data were acquired for a total of approximately 50 chemical species. Elevated abundances of crustal components (Al, Si, K, Ca, Fe) from geological material, carbon (OC, EC) and trace elements (Br, Pb) from vehicle exhausts, carbon (OC, EC) and ions (K(+), Cl(-)) from vegetative burning, ions (SO4(=), NH4(+), Na(+), K(+), Cl(-)) and elements (Cl, Se) from a manure-fueled power plants, and sulfur and trace elements (Na(+), Pb, Se, Ni, V) from an oil-fueled glass plant were found in the resulting source profiles. Abundances of crustal species (e.g. Al, Si, Ca) in the Imperial/Mexicali Valley geological profiles are more than twice those found in central and southern California. Abundances of lead in motor vehicle exhausts indicate different vehicle fleets in border cities. Emission profiles from field burning and charbroil cooking

  17. Near-source mobile methane emission estimates using EPA Method33a and a novel probabilistic approach as a basis for leak quantification in urban areas

    NASA Astrophysics Data System (ADS)

    Albertson, J. D.

    2015-12-01

    Methane emissions from underground pipeline leaks remain an ongoing issue in the development of accurate methane emission inventories for the natural gas supply chain. Application of mobile methods during routine street surveys would help address this issue, but there are large uncertainties in current approaches. In this paper, we describe results from a series of near-source (< 30 m) controlled methane releases where an instrumented van was used to measure methane concentrations during both fixed location sampling and during mobile traverses immediately downwind of the source. The measurements were used to evaluate the application of EPA Method 33A for estimating methane emissions downwind of a source and also to test the application of a new probabilistic approach for estimating emission rates from mobile traverse data.

  18. Characterizing Methane Emissions and Sources from Abandoned Oil and Gas Wells in the United States

    NASA Astrophysics Data System (ADS)

    Ferrara, T.; Townsend-Small, A.; Lyon, D. R.; Lamb, B. K.; Fries, A.

    2015-12-01

    Recent work indicates that methane (CH4) inventories for the United States are underestimated. We made direct measurements of CH4 emissions from 144 abandoned oil and gas wells, a source currently missing from inventories. Most abandoned wells do not emit CH4, but about 2% of wells surveyed contributed 95% of the observed emissions, particularly unplugged wells. Isotopic analyses indicate that wells emit CH4 from natural gas and/or coal bed CH4. Using emission factors developed from these measurements we provide basin wide estimates of CH4 emissions from abandoned wells in the Uintah and Denver-Julesburg basins. Extrapolated nationally, leakage from abandoned wells may contribute significantly to the current CH4 inventory for oil and gas activities. Additional data on emissions and activity factors are needed to accurately determine the contribution of abandoned wells to CH4 budgets, particularly a better characterization of the distribution of high emitters.

  19. Strong photoluminescence emission from GaN grown on amorphous silica substrates by gas source MBE

    NASA Astrophysics Data System (ADS)

    Iwata, K.; Asahi, H.; Asami, K.; Kuroiwa, R.; Gonda, S.

    1998-06-01

    GaN layers are grown on amorphous fused silica glass substrates by gas source MBE using an ion removed electron cyclotron resonance (ECR) radical cell. Reflection high-energy electron diffraction (RHEED) and X-ray diffraction measurements reveal that they are polycrystalline. However, they show a strong photoluminescence emission peak without deep level emission. The emission peak is red-shifted by about 150 meV from that of the excitonic emission peak of GaN grown on a sapphire substrate and has wide spectral half-width (˜250 meV at 77 K). The peak is not corresponding to the donor-acceptor pair (DAP) emission but is excitonic from the excitation power and temperature dependence of PL spectrum. These optical properties indicate that GaN layers grown on a glass substrate are promising for fabrication of large area and low cost light emitting devices and solar cells.

  20. Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies.

    PubMed

    Behera, Sailesh N; Sharma, Mukesh; Aneja, Viney P; Balasubramanian, Rajasekhar

    2013-11-01

    Gaseous ammonia (NH3) is the most abundant alkaline gas in the atmosphere. In addition, it is a major component of total reactive nitrogen. The largest source of NH3 emissions is agriculture, including animal husbandry and NH3-based fertilizer applications. Other sources of NH3 include industrial processes, vehicular emissions and volatilization from soils and oceans. Recent studies have indicated that NH3 emissions have been increasing over the last few decades on a global scale. This is a concern because NH3 plays a significant role in the formation of atmospheric particulate matter, visibility degradation and atmospheric deposition of nitrogen to sensitive ecosystems. Thus, the increase in NH3 emissions negatively influences environmental and public health as well as climate change. For these reasons, it is important to have a clear understanding of the sources, deposition and atmospheric behaviour of NH3. Over the last two decades, a number of research papers have addressed pertinent issues related to NH3 emissions into the atmosphere at global, regional and local scales. This review article integrates the knowledge available on atmospheric NH3 from the literature in a systematic manner, describes the environmental implications of unabated NH3 emissions and provides a scientific basis for developing effective control strategies for NH3.

  1. Qualities of Judgmental Ratings by Four Rater Sources.

    ERIC Educational Resources Information Center

    Tsui, Anne S.

    Quality of performance data yielded by subjective judgment is of major concern to researchers in performance appraisal. However, some confusion exists in the analysis of quality on ratings obtained from different rating scale formats and from different raters. To clarify this confusion, a study was conducted to assess the quality of judgmental…

  2. Emission of volatile organic compounds as affected by rate of application of cattle manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef cattle manure can serve as a valuable nutrient source for crop production. However, emissions of volatile organic compounds (VOCs) following land application may pose a potential off-site odor concern. This study was conducted to evaluate the effects of land application method, N- application...

  3. 75 FR 27249 - Standards of Performance for New Stationary Sources and Emissions Guidelines for Existing Sources...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-14

    ... inadvertent drafting errors in the emissions limits for nitrogen oxides and sulfur dioxide promulgated for... consider as I prepare my comments? II. Background III. Summary of Proposed Amendments A. Nitrogen Oxides..., chlorinated dibenzo-p-dioxins/dibenzofurans, carbon monoxide, nitrogen oxides, hydrogen chloride and...

  4. Nitrogen source and placement effects on soil nitrous oxide emissions from no-till corn.

    PubMed

    Halvorson, Ardell D; Del Grosso, Stephen J

    2012-01-01

    A nitrogen (N) source comparison study was conducted to further evaluate the effects of inorganic N source and placement on growing-season and non-crop period soil nitrous oxide (NO). Commercially available controlled-release N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn ( L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (SuperU and AgrotainPlus contain nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha) near the corn row at emergence and watered into the soil the next day. Subsurface banded ESN (ESNssb) and check (no N applied) treatments were included. Nitrous oxide fluxes were measured during two growing seasons and after harvest using static, vented chambers. All N sources had significantly lower growing-season NO emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources but were greater than the check. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in NT, irrigated corn in semiarid areas. In our study, UAN+AgrotainPlus consistently had the lowest level of NO emissions with no yield loss.

  5. Examining Long-Term Trends in Mobile Source Related Pollutants through Analysis of Emissions, Observations and Model Simulations

    EPA Science Inventory

    Anthropogenic emissions from a variety of sectors including mobile sources have decreased substantially over the past decades despite continued growth in population and economic activity. In this study, we analyze 1990-2010 trends in emission inventories, ambient observations and...

  6. Search for continuous and single day emission from ultra-high-energy sources

    SciTech Connect

    Chen, Mei-Li.

    1993-01-01

    Data from the CYGNUS experiment has been used to search the northern sky for point sources of continuous ultra-high-energy gamma radiation and to examine 51 candidate sources on a daily basis to search for episodic emission. In this paper, we make use of our most recent data to update our previously published results from these searches. The data sample is approximately twice as large as the published data set for continuous emission, and contains an additional year for the daily search. The latest results, up to the time of the conference, will be presented at the meeting.

  7. Search for ultra-high energy emission from Geminga and five unidentified EGRET sources

    SciTech Connect

    Not Available

    1993-01-01

    Data from the CYGNUS extensive air shower array were searched for continuous ultra-high energy (UHE) gamma radiation from five unidentified EGRET sources and from the Geminga pulsar. No evidence for continuous emission from any of these objects was found. Data in the Geminga source bin were also searched for pulsed emission using the recent EGRET ephemeris (237 ms period). No evidence of a periodic signal was found. The 90% confidence level upper limit on the continuous gamma-ray flux above 80 TeV for Geminga is 7.9 [times] 10[sup [minus]14] cm[sup [minus]2] s[sup [minus]1].

  8. Search for ultra-high energy emission from Geminga and five unidentified EGRET sources

    SciTech Connect

    The CYGNUS Collaboration

    1993-05-01

    Data from the CYGNUS extensive air shower array were searched for continuous ultra-high energy (UHE) gamma radiation from five unidentified EGRET sources and from the Geminga pulsar. No evidence for continuous emission from any of these objects was found. Data in the Geminga source bin were also searched for pulsed emission using the recent EGRET ephemeris (237 ms period). No evidence of a periodic signal was found. The 90% confidence level upper limit on the continuous gamma-ray flux above 80 TeV for Geminga is 7.9 {times} 10{sup {minus}14} cm{sup {minus}2} s{sup {minus}1}.

  9. Sources and sinks of methane in the African savanna. CH sub 4 emissions from biomass burning

    SciTech Connect

    Delmas, R.A.; Marenco, A. ); Tathy, J.P.; Cros, B. ); Baudet, J.G.R. )

    1991-04-20

    Sources and sinks of atmospheric methane are studied in savanna regions of west and central Africa. Flux measured over dry savanna soils, using static chambers, is always negative, the average uptake rate being 2 {times} 10{sup 10} molecules/cm{sup 2}/s. In these regions, sources are linked to biomass burning. Methane and CO{sub 2} emission from combustion of savanna plants and wood is studied by both field experiments and laboratory experiments using a combustion chamber. For savanna plants most of the carbon (85%) contained in the biomaterial is volatilized as CO{sub 2} and 0.1 to 0.25% as methane. For graminaceous plants like loudetia simplex the ratio C-CH{sub 4}/C-CO{sub 2} is 0.11%; it is 0.28% for hyparrhenia the other main type of savanna plants and it attains 1.4% for the combustion of wood. In natural fire plumes this ratio is around 0.26% for savanna fires and 0.56 to 2.22% for forest fires. These results show that methane release is highly dependent on the type of combustion. Methane to CO{sub 2} ratios are also studied in vertical profiles in the troposphere taken during the TROPOZ I campaign, an aerial research expedition carried out over west Africa during the bushfire period. Within polluted layers, the average ratio of CH{sub 4} to CO{sub 2} excess over ambient air concentration is 0.34%. These results show that biomass burning in tropical Africa constitutes an important source of atmospheric methane estimated to about 9.2 {times} 10{sup 6} T (CH{sub 4})/yr.

  10. Characterization of decay and emission rates of ultrafine particles in indoor ice rink.

    PubMed

    Kim, J; Lee, K

    2013-08-01

    The purposes of this study were to determine indoor ultrafine particle (UFP, diameter <100 nm) levels in ice rinks and to characterize UFP decay and emission rates. All 15 public ice rinks in Seoul were investigated for UFP and carbon monoxide (CO) concentrations. Three ice rinks did not show peaks in UFP concentrations, and one ice rink used two resurfacers simultaneously. High peaks of UFP and CO concentrations were observed when the resurfacer was operated. The average air change rate in the 11 ice rinks was 0.21 ± 0.13/h. The average decay rates of UFP number concentrations measured by the P-Trak and DiSCmini were 0.54 ± 0.21/h and 0.85 ± 0.34/h, respectively. The average decay rate of UFP surface area concentration was 0.33 ± 0.15/h. The average emission rates of UFP number concentrations measured by P-Trak and DiSCmini were 1.2 × 10(14) ± 6.5 × 10(13) particles/min and 3.3 × 10(14) ± 2.4 × 10(14) particles/min, respectively. The average emission rate of UFP surface area concentration was 3.1 × 10(11) ± 2.0 × 10(11) μm(2)/min. UFP emission rate was associated with resurfacer age. DiSCmini measured higher decay and emission rates than P-Trak due to their different measuring mechanisms and size ranges.

  11. 40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for puncture sealant application affected sources? 63.5988 Section 63.5988 Protection of Environment... Tire Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63.5988 What emission limitations must I meet for puncture sealant application affected sources? (a) You...

  12. 40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for puncture sealant application affected sources? 63.5988 Section 63.5988 Protection of Environment... Tire Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63.5988 What emission limitations must I meet for puncture sealant application affected sources? (a) You...

  13. Ozone Formation Potentials from Different Anthropogenic Emission Sources of Volatile Organic Compounds in California's South Coast Air Basin

    NASA Astrophysics Data System (ADS)

    Chen, J.; Luo, D.; Croes, B.

    2010-12-01

    Different volatile organic compounds (VOC) exhibit different propensities for ozone formation. Two approaches were used to study the relative ozone formation potentials (source reactivities) of different anthropogenic VOC emission source categories in California’s South Coast Air Basin (SoCAB). The first approach combined emission speciation profiles for total organic gases (TOG) with maximum incremental reactivity (MIR) scales for VOC species. The second approach quantified ozone impacts from different sources by performing 3-dimensional air quality model sensitivity analyses involving increased TOG emissions from particular sources. The source reactivities for 58 VOC emission categories in SoCAB derived from these two approaches agree reasonably well (R2 = ~0.9). Both approaches revealed the two emissions source types with the highest TOG reactivity were mobile sources and managed forest burning. Also, a reactivity-based TOG emission inventory for SoCAB in 2005 was produced by combining the source reactivities from both approaches with TOG emissions from anthropogenic source categories. The top five reactivity-based source categories are: light-duty passenger cars, off-road equipments, consumer products, light-duty trucks, and recreational boats. This is in contrast to the mass-based TOG emission inventory, which indicates that farming operations (mainly from animal waste) was one of the five largest mass-based anthropogenic TOG emission sources. Compared to the mass-based TOG emission inventory, the reactivity-based TOG emission inventory more appropriately represents the ozone formation potentials from emission sources, and highlights those sources that should be targeted for future regulations.

  14. Measurement of emissions from air pollution sources. 5. C1-C32 organic compounds from gasoline-powered motor vehicles.

    PubMed

    Schauer, James J; Kleeman, Michael J; Cass, Glen R; Simoneit, Bernd R T

    2002-03-15

    Gas- and particle-phase organic compounds present in the tailpipe emissions from an in-use fleet of gasoline-powered automobiles and light-duty trucks were quantified using a two-stage dilution source sampling system. The vehicles were driven through the cold-start Federal Test Procedure (FTP) urban driving cycle on a transient dynamometer. Emission rates of 66 volatile hydrocarbons, 96 semi-volatile and particle-phase organic compounds, 27 carbonyls, and fine particle mass and chemical composition were quantified. Six isoprenoids and two tricyclic terpanes, which are quantified using new source sampling techniques for semi-volatile organic compounds, have been identified as potential tracers for gasoline-powered motor vehicle emissions. A composite of the commercially distributed California Phase II Reformulated Gasoline used in these tests was analyzed by several analytical methods to quantify the gasoline composition, including some organic compounds that are found in the atmosphere as semi-volatile and particle-phase organic compounds. These results allow a direct comparison of the semi-volatile and particle-phase organic compound emissions from gasoline-powered motor vehicles to the gasoline burned by these vehicles. The distribution of n-alkanes and isoprenoids emitted from the catalyst-equipped gasoline-powered vehicles is the same as the distribution of these compounds found in the gasoline used, whereas the distribution of these compounds in the emissions from the noncatalyst vehicles is very different from the distribution in the fuel. In contrast, the distribution of the polycyclic aromatic hydrocarbons and their methylated homologues in the gasoline is significantly different from the distribution of the PAH in the tailpipe emissions from both types of vehicles.

  15. Monitoring Oilfield Operations and GHG Emissions Sources Using Object-based Image Analysis of High Resolution Spatial Imagery

    NASA Astrophysics Data System (ADS)

    Englander, J. G.; Brodrick, P. G.; Brandt, A. R.

    2015-12-01

    Fugitive emissions from oil and gas extraction have become a greater concern with the recent increases in development of shale hydrocarbon resources. There are significant gaps in the tools and research used to estimate fugitive emissions from oil and gas extraction. Two approaches exist for quantifying these emissions: atmospheric (or 'top down') studies, which measure methane fluxes remotely, or inventory-based ('bottom up') studies, which aggregate leakage rates on an equipment-specific basis. Bottom-up studies require counting or estimating how many devices might be leaking (called an 'activity count'), as well as how much each device might leak on average (an 'emissions factor'). In a real-world inventory, there is uncertainty in both activity counts and emissions factors. Even at the well level there are significant disagreements in data reporting. For example, some prior studies noted a ~5x difference in the number of reported well completions in the United States between EPA and private data sources. The purpose of this work is to address activity count uncertainty by using machine learning algorithms to classify oilfield surface facilities using high-resolution spatial imagery. This method can help estimate venting and fugitive emissions sources from regions where reporting of oilfield equipment is incomplete or non-existent. This work will utilize high resolution satellite imagery to count well pads in the Bakken oil field of North Dakota. This initial study examines an area of ~2,000 km2 with ~1000 well pads. We compare different machine learning classification techniques, and explore the impact of training set size, input variables, and image segmentation settings to develop efficient and robust techniques identifying well pads. We discuss the tradeoffs inherent to different classification algorithms, and determine the optimal algorithms for oilfield feature detection. In the future, the results of this work will be leveraged to be provide activity

  16. 78 FR 6318 - SourceGas Distribution LLC; Notice of Petition for Rate Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission SourceGas Distribution LLC; Notice of Petition for Rate Approval Take notice that on January 15, 2013, SourceGas Distribution LLC (SourceGas) filed a rate election pursuant...

  17. Volcanic gas emissions: constraining magma degassing and volatile sources (Invited)

    NASA Astrophysics Data System (ADS)

    Fischer, T. P.; de Moor, M. J.

    2013-12-01

    the gas phase of < 3 likely imply open-system degassing at pressures > 300MPa (12 km), assuming a starting H2O and CO2 content of 7 and 0.5 wt%, respectively. H2O/CO2 ratios > 10 imply degassing at shallower levels (< 250 MPa) (VolatileCALC). Therefore, degassing can explain some of the observed variations in H2O/CO2 ratios of high T fumaroles, consistent with the loss of volatiles due to magma stalling and saturation at mid-crustal depths. However, source volatile compositions likely also affect these ratios and can be further evaluated using stable isotopes. Combination of approaches provide complimentary information to that from melt inclusions and gas fluxes to arrive at global volatile budgets and to distinguish differences in mantle volatile compositions. 1. Andres, R.J. and A.D. Kasgnoc, 1998. 103: p. 25,251-25,261. 2. Berresheim, H. and W. Jaeschke, JGR, 1983. 88: p. 3732-3740. 3. Plank, T., et al., 2013. EPSL 364: p. 168-179. 4. Rose, W.I., R.E. Stoiber, and L.L. Malinconico, in Andesites: 1982, p. 669-676. 5. Fischer, T.P., Geochemical J., , 2008. 42: p. 21-38. 6. Gerlach, T.M., JGR, 1986. 91(B12): p. 12,177-12,185.

  18. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    SciTech Connect

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-05-01

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions.

  19. Controls on the emission of plant volatiles through stomata: Differential sensitivity of emission rates to stomatal closure explained

    NASA Astrophysics Data System (ADS)

    Niinemets, ÜLo; Reichstein, Markus

    2003-04-01

    Volatile (VOC) flux from leaves may be expressed as GSΔP, where GS is stomatal conductance to specific compound and ΔP partial pressure gradient between the atmosphere and substomatal cavities. It has been suggested that decreases in GS are balanced by increases in ΔP such that stomata cannot control VOC emission. Yet, responses of emission rates of various volatiles to experimental manipulations of stomatal aperture are contrasting. To explain these controversies, a dynamic emission model was developed considering VOC distribution between gas and liquid phases using Henry's law constant (H, Pa m3 mol-1). Our analysis demonstrates that highly volatile compounds such as isoprene and monoterpenes with H values on the order of 103 have gas and liquid pool half-times of a few seconds, and thus cannot be controlled by stomata. More soluble compounds such as alcohols and carboxylic acids with H values of 10-2-101 are controlled by stomata with the degree of stomatal sensitivity varying with H. Inability of compounds with high solubility to support a high partial pressure, and thus to balance ΔP in response to a decrease in GS is the primary explanation for different stomatal sensitivities. For compounds with low H, the analysis predicts bursts of emission after stomatal opening that accord with experimental observations, but that cannot be currently explained. Large within-leaf VOC pool sizes in compounds with low H also increase the system inertia to environmental fluctuations. In conclusion, dynamic models are necessary to simulate diurnal variability of the emissions of compounds that preferably partition to aqueous phase.

  20. Impact of the differential fluence distribution of brachytherapy sources on the spectroscopic dose-rate constant

    SciTech Connect

    Malin, Martha J.; Bartol, Laura J.; DeWerd, Larry A. E-mail: ladewerd@wisc.edu

    2015-05-15

    the spectroscopic technique affect the accuracy of Λ{sub spec}. Results: For all sources studied, the angular and spatial distributions of φ{sub full} were more complex than the distributions used in φ{sub spec}. Differences between Λ{sub spec} and Λ{sub full} ranged from −0.6% to +6.4%, confirming the discrepancies found by Rodriguez and Rogers. The largest contribution to the discrepancy was the assumption of isotropic emission in φ{sub spec}, which caused differences in Λ of up to +5.3% relative to Λ{sub full}. Use of the approximated spatial and energy distributions caused smaller average discrepancies in Λ of −0.4% and +0.1%, respectively. The water-only model introduced an average discrepancy in Λ of −0.4%. Conclusions: The approximations used in φ{sub spec} caused discrepancies between Λ{sub approx,i} and Λ{sub full} of up to 7.8%. With the exception of the energy distribution, the approximations used in φ{sub spec} contributed to this discrepancy for all source models studied. To improve the accuracy of Λ{sub spec}, the spatial and angular distributions of φ{sub full} could be measured, with the measurements replacing the approximated distributions. The methodology used in this work could be used to determine the resolution that such measurements would require by computing the dose-rate constants from phase spaces modified to reflect φ{sub full} binned at different spatial and angular resolutions.

  1. Near-infrared spectroscopy of faint discrete X-ray point sources constituting the Galactic ridge X-ray emission

    NASA Astrophysics Data System (ADS)

    Morihana, Kumiko; Tsujimoto, Masahiro; Dubath, Pierre; Yoshida, Tessei; Suzuki, Kensuke; Ebisawa, Ken

    2016-08-01

    The Galactic Ridge X-ray Emission (GRXE) is an apparently extended X-ray emission along the Galactic plane. The X-ray spectrum is characterized by a hard continuum with a strong Fe K emission feature in the 6-7 keV band. A substantial fraction (˜80%) of the GRXE in the Fe band was resolved into point sources by deep Chandra imaging observations; thus GRXE is mostly composed of dim Galactic X-ray point sources, at least in this energy band. To investigate the populations of these dim X-ray point sources, we carried out near-infrared (NIR) follow-up spectroscopic observations in two deep Chandra fields located in the Galactic plane at (l, b) = (0.1°, -1.4°) and (28.5°, 0.0°) using NTT/SofI and Subaru/MOIRCS. We obtained well-exposed NIR spectra from 65 objects and found that there are three main classes of Galactic sources based on the X-ray color and NIR spectral features: those having (A) hard X-ray spectra and NIR emission features such as H I (Brγ), He I, and He II (2 objects), (B) soft X-ray spectra and NIR absorption features such as H I, Na I, Ca I, and CO (46 objects), and (C) hard X-ray spectra and NIR absorption features such as H I, Na I, Ca I, and CO (17 objects). From these features, we argue that class A sources are cataclysmic variables (CVs), and class B sources are late-type stars with enhanced coronal activity, which is in agreement with current knowledge. Class C sources possibly belong to a new group of objects, which has been poorly studied so far. We argue that the candidate sources for class C are the binary systems hosting white dwarfs and late-type companions with very low accretion rates. It is likely that this newly recognized class of sources contribute to a non-negligible fraction of the GRXE, especially in the Fe K band.

  2. Chemical composition of major VOC emission sources in the Seoul atmosphere.

    PubMed

    Na, Kwangsam; Kim, Yong Pyo; Moon, Il; Moon, Kil-Choo

    2004-04-01

    This paper describes a chemical analysis of volatile organic compounds (VOCs) for five emission sources in Seoul. The source categories included motor vehicle exhaust, gasoline evaporation, paint solvents, natural gas and liquefied petroleum gas (LPG). These sources were selected because they have been known to emit significant quantities of VOCs in the Seoul area (more than 5% of the total emission inventory). Chemical compositions of the five emission sources are presented for a group of 45 C2-C9 VOCs. Motor vehicle exhaust profiles were developed by conducting an urban tunnel study. These emissions profiles were distinguished from the other emission profiles by a high weight percentage of butanes over seasons and propane in the wintertime. It was found that this is due to the wide use of butane-fueled vehicles. To obtain gasoline vapor profiles, gasoline samples from five major brands for each season were selected. The brands were blended on the basis of the marketshare of these brands in Seoul area. Raoult's law was used to calculate gasoline evaporative compositions based on the liquid gasoline compositions. The measured and estimated gasoline vapor compositions were found to be in good agreement. Vehicle and gasoline evaporation profiles were made over seasons because of the seasonal change in their compositions. Paint solvent emissions profiles were produced based on a product-use survey and sales figures. These profiles are a composite of four major oil-based paints and thinning solvent. The source profile of natural gas was made on a methane-free basis. It was found that Ethane and propane were the most abundant compounds accounting for 95% of the natural gas composition. LPG was largely composed of propane and ethane and the remaining components were minor contributors.

  3. K-alpha x-ray source using high energy and high repetition rate laser system for phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Serbanescu, Cristina; Fourmaux, Sylvain; Kieffer, Jean-Claude; Kincaid, Russell; Krol, Andrzej

    2009-08-01

    K-alpha x-ray sources from laser produced plasmas provide completely new possibilities for x-ray phase-contrast imaging applications. By tightly focusing intense femtosecond laser pulses onto a solid target, K-alpha x-ray pulses are generated through the interaction of energetic electrons created in the plasma with the bulk target. In this paper, we present a continuous and efficient Mo K-alpha x-ray source produced by a femtosecond laser system operating at 100 Hz repetition rate with maximum pulse energy of 110 mJ before compression. The source has x-ray conversion efficiency greater than 10-5 into K-alpha line emission. In preparation for phase contrast imaging applications, the size of the resultant K-alpha x-ray emission spot has been also characterized. The source exhibits sufficient spatial coherence to observe phase contrast. We observe a relatively small broadening of the K-alpha source size compared to the size of the laser beam itself. Detailed characterization of the source including the x-ray spectrum and the x-ray average yield along with phase contrast images of test objects will be presented.

  4. Investigating Sources and Emissions of Volatile Organic Compounds in California's San Joaquin Valley

    NASA Astrophysics Data System (ADS)

    Gentner, D. R.; Harley, R. A.; Weber, R.; Karlik, J. F.; Goldstein, A. H.

    2011-12-01

    Emissions of Volatile Organic Compounds (VOCs) are regulated both as primary air pollutants and as precursors to the formation of secondary organic aerosol and tropospheric ozone. The San Joaquin Valley, a non-attainment area for ozone and PM2.5, contains a variety of point, area, and mobile VOC sources that contribute to both primary and secondary pollution. Using ambient measurements of over 100 different VOCs and Intermediate Volatility Organic Compounds (IVOCs) made at multiple field sites, we assess the magnitude and importance of various VOC sources in the San Joaquin Valley. Hourly measurements were made during the spring and summer of 2010 via in-situ gas chromatography in Bakersfield, CA as part of the CalNex experiment and also at a rural site located 100 km north of Bakersfield. Additionally, in-situ measurements of fresh motor vehicle exhaust were made in Oakland's Caldecott tunnel during the summer of 2010. Measurements include a broad array of anthropogenic and biogenic VOCs ranging in size from 1 to 17 carbon atoms, including many compounds with functional groups or substituents (e.g. aldehydes, ketones, alcohols, halogens, sulfur, & nitrogen). Using statistical methods of source apportionment, covariance, source receptor modeling, and air parcel back trajectories, we assess the impact of various sources on observed VOC concentrations at our field sites in the San Joaquin Valley. Prevalent sources include gasoline and diesel-vehicle exhaust, petroleum extraction/refining, biogenic emissions from agricultural crops and natural vegetation, and emissions from dairy operations and animal husbandry. We use measurements of fresh motor vehicle emissions from the Caldecott tunnel to constrain apportionment of gasoline and diesel-related VOCs and IVOCs in the San Joaquin Valley. Initial results from Bakersfield show substantial influence from local anthropogenic VOC sources, but there is evidence for transport of emissions from both anthropogenic and biogenic

  5. Source location determination of Uranian kilometric radiation from ray tracing and emission lobe modelling

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.

    1991-01-01

    We use an analytical fit to an emission lobe profile together with three-dimensional ray tracing to model the broad-banded smooth Uranian kilometric radiation (UKR). We assume the radiation is gyroemission from sources along magnetic field lines. Using an iterative technique that modifies the lobe function and source region, the results are compared to observations at a frequency of 481 kHz. The best-fit calculations are compared to previously published models and to recent ultraviolet (UV) observations.

  6. 7 CFR 1822.268 - Rates, terms, and source of funds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... under Public Law 103-354 will be the lower of the interest rates in effect at the time of loan approval... 7 Agriculture 12 2011-01-01 2011-01-01 false Rates, terms, and source of funds. 1822.268 Section... Site Loan Policies, Procedures, and Authorizations § 1822.268 Rates, terms, and source of funds....

  7. 7 CFR 1822.268 - Rates, terms, and source of funds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... under Public Law 103-354 will be the lower of the interest rates in effect at the time of loan approval... 7 Agriculture 12 2014-01-01 2013-01-01 true Rates, terms, and source of funds. 1822.268 Section... Site Loan Policies, Procedures, and Authorizations § 1822.268 Rates, terms, and source of funds....

  8. Enhancing spontaneous emission rates of molecules using nanopatterned multilayer hyperbolic metamaterials.

    PubMed

    Lu, Dylan; Kan, Jimmy J; Fullerton, Eric E; Liu, Zhaowei

    2014-01-01

    Plasmonic nanostructures have been extensively used to manipulate the spontaneous light emission rate of molecules and their radiative efficiency. Because molecules near a metallic surface experience a different environment than in free space, their spontaneous radiative emission rate is generally enhanced. Such enhancement, measured by means of the Purcell factor, arises as a consequence of the overlap between the surface plasmon mode frequency and the emission spectrum of the molecule. However, such overlap is available only for a few narrow bands of frequency due to the limited plasmonic materials existing in nature. Although this limitation can be overcome by using hyperbolic metamaterials (HMMs)—a type of nanoscale artificial material with hyperbolic dispersion relations—the Purcell factor and the radiative power have remained relatively low. Here, we show that by nanopatterning a hyperbolic metamaterial made of Ag and Si multilayers, the spontaneous emission rate of rhodamine dye molecules is enhanced 76-fold at tunable frequencies and the emission intensity of the dye increases by ~80-fold compared with the same hyperbolic metamaterial without nanostructuring. We explain these results using a dynamic Lorentzian model in the time domain.

  9. Nanoparticle emissions from 11 non-vehicle exhaust sources - A review

    NASA Astrophysics Data System (ADS)

    Kumar, Prashant; Pirjola, Liisa; Ketzel, Matthias; Harrison, Roy M.

    2013-03-01

    Nanoparticle emissions from road vehicles have been studied extensively in the recent past due to their dominant contribution towards the total airborne particle number concentrations (PNCs) found in the urban atmospheric environment. In view of upcoming tighter vehicle emission standards and adoption of cleaner fuels in many parts of the world, the contribution to urban nanoparticles from non-vehicle exhaust sources (NES) may become more pronounced in future. As of now, only limited information exists on nanoparticle emissions from NES through the discretely published studies. This article presents critically synthesised information in a consolidated manner on 11 NES (i.e. road-tyre interaction, construction and demolition, aircraft, ships, municipal waste incineration, power plants, domestic biomass burning, forest fires, cigarette smoking, cooking, and secondary formation). Source characteristics and formation mechanisms of nanoparticles emitted from each NES are firstly discussed, followed by their emission strengths, airborne concentrations and physicochemical characteristics. Direct comparisons of the strengths of NES are not straightforward but an attempt has been made to discuss their importance relative to the most prominent source (i.e. road vehicles) of urban nanoparticles. Some interesting comparisons emerged such as 1 kg of fast and slow wood burning produces nearly the same number of particles as for each km driven by a heavy duty vehicle (HDV) and a light duty vehicle, respectively. About 1 min of cooking on gas can produce the similar particle numbers generated by ˜10 min of cigarette smoking or 1 m travel by a HDV. Apportioning the contribution of numerous sources from the bulk measured airborne PNCs is essential for determining their relative importance. Receptor modelling methods for estimation of source emission contributions are discussed. A further section evaluates the likely exposure risks, health and regulatory implications associated with

  10. Direct oceanic emissions unlikely to account for the missing source of atmospheric carbonyl sulfide

    NASA Astrophysics Data System (ADS)

    Lennartz, Sinikka T.; Marandino, Christa A.; von Hobe, Marc; Cortes, Pau; Quack, Birgit; Simo, Rafel; Booge, Dennis; Pozzer, Andrea; Steinhoff, Tobias; Arevalo-Martinez, Damian L.; Kloss, Corinna; Bracher, Astrid; Röttgers, Rüdiger; Atlas, Elliot; Krüger, Kirstin

    2017-01-01

    The climate active trace-gas carbonyl sulfide (OCS) is the most abundant sulfur gas in the atmosphere. A missing source in its atmospheric budget is currently suggested, resulting from an upward revision of the vegetation sink. Tropical oceanic emissions have been proposed to close the resulting gap in the atmospheric budget. We present a bottom-up approach including (i) new observations of OCS in surface waters of the tropical Atlantic, Pacific and Indian oceans and (ii) a further improved global box model to show that direct OCS emissions are unlikely to account for the missing source. The box model suggests an undersaturation of the surface water with respect to OCS integrated over the entire tropical ocean area and, further, global annual direct emissions of OCS well below that suggested by top-down estimates. In addition, we discuss the potential of indirect emission from CS2 and dimethylsulfide (DMS) to account for the gap in the atmospheric budget. This bottom-up estimate of oceanic emissions has implications for using OCS as a proxy for global terrestrial CO2 uptake, which is currently impeded by the inadequate quantification of atmospheric OCS sources and sinks.

  11. Household materials as emission sources of naphthalene in Canadian homes and their contribution to indoor air

    NASA Astrophysics Data System (ADS)

    Kang, Dong Hwa; Choi, Dong Hee; Won, Doyun; Yang, Wenping; Schleibinger, Hans; David, Jacinthe

    2012-04-01

    The objective of this study was to identify household materials that may contribute to the indoor naphthalene concentration in Canadian homes. Ninety-nine household materials including building materials, furnishings, and consumer products were tested. These materials included well-known naphthalene-containing products such as mothballs as well as building and consumer products where naphthalene could have been either added as part of a liquid formulation or used as a chemical intermediate in the manufacture of solid materials and product components. A fast screening method was used to determine the naphthalene concentration in a micro-scale test chamber. The tested materials were ranked based on the naphthalene emission strength combined with the amount of products typically used in homes. As expected, the results showed that mothballs, which had the highest emission factor, are one of the predominant sources. Interestingly, vinyl and wooden furniture with high emission factors and painted walls and ceiling with large surface areas were found to be important sources with the source strength even larger than those of mothballs when maximum emission factors were assumed for these building materials and furnishings. This suggests that some building materials and furnishings could be significant contributors to indoor naphthalene concentrations. This study shows that selecting materials with lower naphthalene emission factors could be one of many ways to reduce the indoor naphthalene concentration.

  12. Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol

    NASA Astrophysics Data System (ADS)

    Sihota, Natasha J.; Mayer, K. Ulrich; Toso, Mark A.; Atwater, Joel F.

    2013-08-01

    The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation—related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur—even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 9 μmol m- 2 s- 1. At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 393 μmol m- 2 s- 1. Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or

  13. Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol.

    PubMed

    Sihota, Natasha J; Mayer, K Ulrich; Toso, Mark A; Atwater, Joel F

    2013-08-01

    The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation-related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur-even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 9 μmol m(-2) s(-1). At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 393 μmol m(-2) s(-1). Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion

  14. Calculated ionization rates, ion densities, and airglow emission rates due to precipitating electrons in the nightside ionosphere of Mars

    NASA Technical Reports Server (NTRS)

    Haider, S. A.; Kim, J.; Nagy, A. F.; Keller, C. N.; Verigin, M. I.; Gringauz, K. I.; Shutte, N. M.; Szego, K.; Kiraly, P.

    1992-01-01

    The calculations presented in this paper clearly establish that the electron fluxes measured by the HARP instrument, carried on board Phobos 2, could cause significant electron impact ionization and excitation in the nightside atmosphere of Mars, if these electrons actually do precipitate. The calculated peak electron densities were found to be about a factor of 2 larger than the mean observed nightside densities, indicating that if a significant fraction of the measured electrons actually precipitate, they could be the dominant mechanism responsible for maintaining the nightside ionosphere. The calculated zenith column emission rates of the O I 5577-A and 6300-A and CO Cameron band emissions, due to electron impact and dissociative recombination mechanisms, were found to be significant.

  15. Development of a Mobile Tracer Correlation Method for Assessment of Air Emissions from Landfills and Other Area Sources

    EPA Science Inventory

    Information form the previously approved extended abstract A standardized area source measurement method based on mobile tracer correlation was used for methane emissions assessment in 52 field deployments...

  16. Quantifying Atmospheric Mercury Emissions Sources in coastal California from Shipboard Measurements During CalNex 2010

    NASA Astrophysics Data System (ADS)

    Weiss-Penzias, P. S.; Lerner, B. M.; Williams, E. J.; Bates, T. S.; Gaston, C. J.; Prather, K. A.

    2011-12-01

    Mercury is a neurotoxin that can bioaccumulate in aquatic ecosystems to levels that are unsafe for humans and biota. It has both natural and anthropogenic sources to the atmosphere, where it can be transported and undergo transformations that lead to its deposition in both wet and dry forms. Due to recent surveys of mercury in fish in California that show widespread contamination, there is great interest in knowing the source of this mercury, whether it be from local, regional, or global emissions. In this study we made simultaneous measurements of gaseous elemental mercury (GEM), CO2, CO, NOx, SO2, O3, and meteorology during the spring of 2010 (May 14-June 8) on board the research vessel Atlantis during the CalNex campaign. The goal of this study was to observe and quantify emissions of GEM from known and potential sources along the California coast, including an incinerator, oil refineries, cargo ships, and natural ocean emissions. Additionally, an understanding of the behavior of GEM in the marine boundary layer under land-sea breeze conditions was sought. Our results indicate that on at least one occasion when the ship was located in the San Pedro harbor, emissions from an incinerator were observed, as indicated by high concentrations of GEM and unique single particle chemical composition. Using the ratio of the enhancements in GEM and CO and the CO emissions inventory for this facility, it was estimated that the annual GEM emissions were 11 +/- 5 kg. This is a factor of 5 lower than the reported total mercury emissions inventory for this facility in 2008. The discrepancy may be explained if a significant fraction of the emissions were gaseous oxidized and particulate mercury, since only GEM was measured. Additionally, a plume from a cargo ship was intercepted and the GEM/CO2 enhancement ratio indicated that approximately 13 tonnes of GEM are emitted from shipping worldwide, assuming values for global fuel usage and a CO2/fuel burned mass ratio. In spite of

  17. Volatile organic compounds from vegetation in southern Yunnan Province, China: Emission rates and some potential regional implications

    NASA Astrophysics Data System (ADS)

    Geron, Chris; Owen, Sue; Guenther, Alex; Greenberg, Jim; Rasmussen, Rei; Hui Bai, Jian; Li, Qing-Jun; Baker, Brad

    Little information is currently available regarding emissions of biogenic volatile organic compounds (BVOCs) in southern Asia. To address the need for BVOC emission estimates in regional atmospheric chemistry simulations, 95 common plant species were screened for emissions of BVOC in and near the Xishuangbanna Tropical Biological Gardens in southern Yunnan Province, Peoples' Republic of China in February 2003. In situ measurements with leaf cuvettes and branch bag enclosures were used in combination with portable gas chromatography, flame ionization, photoionization, and mass spectral detection to identify and quantify BVOC emissions. Forty-four of the species examined emitted isoprene at rates exceeding 20 μg C g -1 (leaf dry weight) h -1. An emphasis was placed on the genus Ficus, which is important in the region and occupies a wide range of ecological niches. Several species in the footprint of a nearby flux tower were also examined. Several palm species and an abundant fern ( Cyclosorus parasiticus) emitted substantial amounts of isoprene, and probably accounted for observed daytime mean isoprene fluxes from the understory of a Hevea brasiliensis plantation of 1.0 and 0.15 mg C m -2 h -1 during the wet and dry seasons, respectively. These measurements verify that both the forest floor and canopy in this region can be sources of isoprene. Monoterpene emissions exceeded 1.0 μg-C g -1 (leaf dry weight) h -1 from only 4 of 38 species surveyed, including some Ficus species and H. brasiliensis. However most of the trees of the latter species were sparsely foliated due to dry season senescence, and emission factors are approximately an order of magnitude lower than those reported during the wet season. BVOC emission rates and physiology of many species are impacted by reduced moisture availability, especially Mangifera indica. South Asia is a region undergoing rapid landuse change and forest plantation establishment, with large increases in area of high BVOC

  18. Source apportionment of stack emissions from research and development facilities using positive matrix factorization

    NASA Astrophysics Data System (ADS)

    Ballinger, Marcel Y.; Larson, Timothy V.

    2014-12-01

    Research and development (R&D) facility emissions are difficult to characterize due to their variable processes, changing nature of research, and large number of chemicals. Positive matrix factorization (PMF) was applied to volatile organic compound (VOC) concentrations measured in the main exhaust stacks of four different R&D buildings to identify the number and composition of major contributing sources. PMF identified between 9 and 11 source-related factors contributing to stack emissions, depending on the building. Similar factors between buildings were major contributors to trichloroethylene (TCE), acetone, and ethanol emissions; other factors had similar profiles for two or more buildings but not all four. At least one factor for each building was identified that contained a broad mix of many species and constraints were used in PMF to modify the factors to resemble more closely the off-shift concentration profiles. PMF accepted the constraints with little decrease in model fit.

  19. Inventory of emissions from non-automotive vehicular sources. Final report

    SciTech Connect

    Taback, H.J.; Macko, J.F.; Parker, N.R.; Dale, D.A.; Erlich, S.

    1980-02-01

    The report presents the results of a program to develop methodologies for the inventory of emissions from nonautomotive vehicular sources, which are applicable in all areas of California; and using these methods, compile an inventory of emissions for 1977 for the four counties comprising the South Coast Air Basin. In this study, nonautomotive vehicular sources were defined as construction equipment, farm vehicles, industrial vehicles, and small boats. The general approach was to determine total annual fuel consumption by vehicle type, then multiply each total by the appropriate EPA emission factors. For construction equipment, the method is based upon the level of construction activity, miles of roadway constructed, and human population. For farm vehicles, the method is based upon the annual number of harvested acres of each type of crop. For industrial vehicles, the method is based upon the vehicle population and usage factors. Boats are separated into pleasure and commercial categories, with usage and fuel consumption factors for each group.

  20. Theory of light emission from a dipole source embedded in a chiral sculptured thin film.

    PubMed

    Mackay, Tom G; Lakhtakia, A