40 CFR Table 1a to Subpart Zzzz of... - Emission Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., and Reconstructed Spark Ignition, 4SRB Stationary RICE > 500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE > 500 HP Located at a... stationary RICE >500 HP located at a major source of HAP emissions: For each . . . You must meet the...

Multiscale Spatial Modeling of Human Exposure from Local Sources to Global Intake.

PubMed

Wannaz, Cedric; Fantke, Peter; Jolliet, Olivier

2018-01-16

Exposure studies, used in human health risk and impact assessments of chemicals, are largely performed locally or regionally. It is usually not known how global impacts resulting from exposure to point source emissions compare to local impacts. To address this problem, we introduce Pangea, an innovative multiscale, spatial multimedia fate and exposure assessment model. We study local to global population exposure associated with emissions from 126 point sources matching locations of waste-to-energy plants across France. Results for three chemicals with distinct physicochemical properties are expressed as the evolution of the population intake fraction through inhalation and ingestion as a function of the distance from sources. For substances with atmospheric half-lives longer than a week, less than 20% of the global population intake through inhalation (median of 126 emission scenarios) can occur within a 100 km radius from the source. This suggests that, by neglecting distant low-level exposure, local assessments might only account for fractions of global cumulative intakes. We also study ∼10 000 emission locations covering France more densely to determine per chemical and exposure route which locations minimize global intakes. Maps of global intake fractions associated with each emission location show clear patterns associated with population and agriculture production densities.

An FBG acoustic emission source locating system based on PHAT and GA

NASA Astrophysics Data System (ADS)

Shen, Jing-shi; Zeng, Xiao-dong; Li, Wei; Jiang, Ming-shun

2017-09-01

Using the acoustic emission locating technology to monitor the health of the structure is important for ensuring the continuous and healthy operation of the complex engineering structures and large mechanical equipment. In this paper, four fiber Bragg grating (FBG) sensors are used to establish the sensor array to locate the acoustic emission source. Firstly, the nonlinear locating equations are established based on the principle of acoustic emission, and the solution of these equations is transformed into an optimization problem. Secondly, time difference extraction algorithm based on the phase transform (PHAT) weighted generalized cross correlation provides the necessary conditions for the accurate localization. Finally, the genetic algorithm (GA) is used to solve the optimization model. In this paper, twenty points are tested in the marble plate surface, and the results show that the absolute locating error is within the range of 10 mm, which proves the accuracy of this locating method.

Characterizing and locating air pollution sources in a complex industrial district using optical remote sensing technology and multivariate statistical modeling.

PubMed

Chang, Pao-Erh Paul; Yang, Jen-Chih Rena; Den, Walter; Wu, Chang-Fu

2014-09-01

Emissions of volatile organic compounds (VOCs) are most frequent environmental nuisance complaints in urban areas, especially where industrial districts are nearby. Unfortunately, identifying the responsible emission sources of VOCs is essentially a difficult task. In this study, we proposed a dynamic approach to gradually confine the location of potential VOC emission sources in an industrial complex, by combining multi-path open-path Fourier transform infrared spectrometry (OP-FTIR) measurement and the statistical method of principal component analysis (PCA). Close-cell FTIR was further used to verify the VOC emission source by measuring emitted VOCs from selected exhaust stacks at factories in the confined areas. Multiple open-path monitoring lines were deployed during a 3-month monitoring campaign in a complex industrial district. The emission patterns were identified and locations of emissions were confined by the wind data collected simultaneously. N,N-Dimethyl formamide (DMF), 2-butanone, toluene, and ethyl acetate with mean concentrations of 80.0 ± 1.8, 34.5 ± 0.8, 103.7 ± 2.8, and 26.6 ± 0.7 ppbv, respectively, were identified as the major VOC mixture at all times of the day around the receptor site. As the toxic air pollutant, the concentrations of DMF in air samples were found exceeding the ambient standard despite the path-average effect of OP-FTIR upon concentration levels. The PCA data identified three major emission sources, including PU coating, chemical packaging, and lithographic printing industries. Applying instrumental measurement and statistical modeling, this study has established a systematic approach for locating emission sources. Statistical modeling (PCA) plays an important role in reducing dimensionality of a large measured dataset and identifying underlying emission sources. Instrumental measurement, however, helps verify the outcomes of the statistical modeling. The field study has demonstrated the feasibility of using multi-path OP-FTIR measurement. The wind data incorporating with the statistical modeling (PCA) may successfully identify the major emission source in a complex industrial district.

New approaches for automatic threedimensional source localization of acoustic emissions--Applications to concrete specimens.

PubMed

Kurz, Jochen H

2015-12-01

The task of locating a source in space by measuring travel time differences of elastic or electromagnetic waves from the source to several sensors is evident in varying fields. The new concepts of automatic acoustic emission localization presented in this article are based on developments from geodesy and seismology. A detailed description of source location determination in space is given with the focus on acoustic emission data from concrete specimens. Direct and iterative solvers are compared. A concept based on direct solvers from geodesy extended by a statistical approach is described which allows a stable source location determination even for partly erroneous onset times. The developed approach is validated with acoustic emission data from a large specimen leading to travel paths up to 1m and therefore to noisy data with errors in the determined onsets. The adaption of the algorithms from geodesy to the localization procedure of sources of elastic waves offers new possibilities concerning stability, automation and performance of localization results. Fracture processes can be assessed more accurately. Copyright © 2015 Elsevier B.V. All rights reserved.

40 CFR Table 2b to Subpart Zzzz of... - Operating Limitations for New and Reconstructed 2SLB and Compression Ignition Stationary RICE...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Reconstructed 2SLB and Compression Ignition Stationary RICE >500 HP Located at a Major Source of HAP Emissions, New and Reconstructed 4SLB Stationary RICE â¥250 HP Located at a Major Source of HAP Emissions, Existing Compression Ignition Stationary RICE >500 HP, and Existing 4SLB Stationary RICE >500 HP Located at...

Study of acoustic emission during mechanical tests of large flight weight tank structure

NASA Technical Reports Server (NTRS)

Mccauley, B. O.; Nakamura, Y.; Veach, C. L.

1973-01-01

A PPO-insulated, flight-weight, subscale, aluminum tank was monitored for acoustic emissions during a proof test and during 100 cycles of environmental test simulating space flights. The use of a combination of frequency filtering and appropriate spatial filtering to reduce background noise was found to be sufficient to detect acoustic emission signals of relatively small intensity expected from subcritical crack growth in the structure. Several emission source locations were identified, including the one where a flaw was detected by post-test x-ray inspections. For most source locations, however, post-test inspections did not detect flaws; this was partially attributed to the higher sensitivity of the acoustic emission technique than any other currently available NDT method for detecting flaws. For these non-verifiable emission sources, a problem still remains in correctly interpreting observed emission signals.

Identifying sources of fugitive emissions in industrial facilities using trajectory statistical methods

NASA Astrophysics Data System (ADS)

Brereton, Carol A.; Johnson, Matthew R.

2012-05-01

Fugitive pollutant sources from the oil and gas industry are typically quite difficult to find within industrial plants and refineries, yet they are a significant contributor of global greenhouse gas emissions. A novel approach for locating fugitive emission sources using computationally efficient trajectory statistical methods (TSM) has been investigated in detailed proof-of-concept simulations. Four TSMs were examined in a variety of source emissions scenarios developed using transient CFD simulations on the simplified geometry of an actual gas plant: potential source contribution function (PSCF), concentration weighted trajectory (CWT), residence time weighted concentration (RTWC), and quantitative transport bias analysis (QTBA). Quantitative comparisons were made using a correlation measure based on search area from the source(s). PSCF, CWT and RTWC could all distinguish areas near major sources from the surroundings. QTBA successfully located sources in only some cases, even when provided with a large data set. RTWC, given sufficient domain trajectory coverage, distinguished source areas best, but otherwise could produce false source predictions. Using RTWC in conjunction with CWT could overcome this issue as well as reduce sensitivity to noise in the data. The results demonstrate that TSMs are a promising approach for identifying fugitive emissions sources within complex facility geometries.

Acoustic Emission Source Location Using a Distributed Feedback Fiber Laser Rosette

PubMed Central

Huang, Wenzhu; Zhang, Wentao; Li, Fang

2013-01-01

This paper proposes an approach for acoustic emission (AE) source localization in a large marble stone using distributed feedback (DFB) fiber lasers. The aim of this study is to detect damage in structures such as those found in civil applications. The directional sensitivity of DFB fiber laser is investigated by calculating location coefficient using a method of digital signal analysis. In this, autocorrelation is used to extract the location coefficient from the periodic AE signal and wavelet packet energy is calculated to get the location coefficient of a burst AE source. Normalization is processed to eliminate the influence of distance and intensity of AE source. Then a new location algorithm based on the location coefficient is presented and tested to determine the location of AE source using a Delta (Δ) DFB fiber laser rosette configuration. The advantage of the proposed algorithm over the traditional methods based on fiber Bragg Grating (FBG) include the capability of: having higher strain resolution for AE detection and taking into account two different types of AE source for location. PMID:24141266

An efficient closed-form solution for acoustic emission source location in three-dimensional structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xibing; Dong, Longjun, E-mail: csudlj@163.com; Australian Centre for Geomechanics, The University of Western Australia, Crawley, 6009

This paper presents an efficient closed-form solution (ECS) for acoustic emission(AE) source location in three-dimensional structures using time difference of arrival (TDOA) measurements from N receivers, N ≥ 6. The nonlinear location equations of TDOA are simplified to linear equations. The unique analytical solution of AE sources for unknown velocity system is obtained by solving the linear equations. The proposed ECS method successfully solved the problems of location errors resulting from measured deviations of velocity as well as the existence and multiplicity of solutions induced by calculations of square roots in existed close-form methods.

Remote sensing of a NTC radio source from a Cluster tilted spacecraft pair

NASA Astrophysics Data System (ADS)

Décréau, Pierrette; Kougblénou, Séna; Lointier, Guillaume; Rauch, Jean Louis; Trotignon, Jean Gabriel; Vallières, Xavier; Canu, Patrick; Rochel Grimald, Sandrine; El-Lemdani Mazouz, Farida; Darrouzet, Fabien

2014-05-01

The non-thermal continuum (NTC) radiation is a radio wave produced within the magnetosphere of a planet. It has been observed in space around Earth since the '70s, and within the magnetospheres of other planets since the late '80s. A new study using ESA's Cluster mission has shown improved precision in determining the source of various radio emissions produced by the Earth. The experiment involved tilting one of the four identical Cluster spacecraft to measure the electric field of this emission in three dimensions for the first time. Our analysis of a NTC case event pinpointed a small deviation from the generally assumed (circular) polarization of this emission. We show that classical triangulation, in this case using three of the spacecraft located thousands of kilometres apart, can lead to an erroneous source location. A second method, using the new 3D electric field measurements, indicated a source located along the plasmapause at medium geomagnetic latitude, far away from the source location estimated by triangulation. Cluster observations reveal that this NTC source emits from the flank of the plasmapause towards the polar cap. Understanding the source of NTC waves will help with the broader understanding of their generation, amplification, and propagation.

Characterization of Methane Emission Sources Using Genetic Algorithms and Atmospheric Transport Modeling

NASA Astrophysics Data System (ADS)

Cao, Y.; Cervone, G.; Barkley, Z.; Lauvaux, T.; Deng, A.; Miles, N.; Richardson, S.

2016-12-01

Fugitive methane emission rates for the Marcellus shale area are estimated using a genetic algorithm that finds optimal weights to minimize the error between simulated and observed concentrations. The overall goal is to understand the relative contribution of methane due to Shale gas extraction. Methane sensors were installed on four towers located in northeastern Pennsylvania to measure atmospheric concentrations since May 2015. Inverse Lagrangian dispersion model runs are performed from each of these tower locations for each hour of 2015. Simulated methane concentrations at each of the four towers are computed by multiplying the resulting footprints from the atmospheric simulations by thousands of emission sources grouped into 11 classes. The emission sources were identified using GIS techniques, and include conventional and unconventional wells, different types of compressor stations, pipelines, landfills, farming and wetlands. Initial estimates for each source are calculated based on emission factors from EPA and few regional studies. A genetic algorithm is then used to identify optimal emission rates for the 11 classes of methane emissions and to explore extreme events and spatial and temporal structures in the emissions associated with natural gas activities.

Back-trajectory modeling of high time-resolution air measurement data to separate nearby sources

EPA Science Inventory

Strategies to isolate air pollution contributions from sources is of interest as voluntary or regulatory measures are undertaken to reduce air pollution. When different sources are located in close proximity to one another and have similar emissions, separating source emissions ...

76 FR 66886 - Oil and Natural Gas Sector: New Source Performance Standards and National Emission Standards for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-28

...-AP76 Oil and Natural Gas Sector: New Source Performance Standards and National Emission Standards for... and Natural Gas Sector: New Source Performance Standards and National Emission Standards for Hazardous... be charged for copying. World Wide Web. The EPA Web site for this rulemaking is located at: http...

Nonparametric Trajectory Analysis of R2PIER Data

EPA Science Inventory

Strategies to isolate air pollution contributions from sources is of interest as voluntary or regulatory measures are undertaken to reduce air pollution. When different sources are located in close proximity to one another and have similar emissions, separating source emissions ...

Development of unauthorized airborne emission source identification procedure

NASA Astrophysics Data System (ADS)

Shtripling, L. O.; Bazhenov, V. V.; Varakina, N. S.; Kupriyanova, N. P.

2018-01-01

The paper presents the procedure for searching sources of unauthorized airborne emissions. To make reasonable regulation decisions on airborne pollutant emissions and to ensure the environmental safety of population, the procedure provides for the determination of a pollutant mass emission value from the source being the cause of high pollution level and the search of a previously unrecognized contamination source in a specified area. To determine the true value of mass emission from the source, the minimum of the mean-root-square mismatch criterion between the computed and measured pollutant concentration in the given location is used.

Quantifying co-benefits of source-specific CO2 emission reductions in Canada and the US: An adjoint sensitivity analysis

NASA Astrophysics Data System (ADS)

Zhao, S.; Soltanzadeh, M.; Pappin, A. J.; Hakami, A.; Turner, M. D.; Capps, S.; Henze, D. K.; Percell, P.; Bash, J. O.; Napelenok, S. L.; Pinder, R. W.; Russell, A. G.; Nenes, A.; Baek, J.; Carmichael, G. R.; Stanier, C. O.; Chai, T.; Byun, D.; Fahey, K.; Resler, J.; Mashayekhi, R.

2016-12-01

Scenario-based studies evaluate air quality co-benefits by adopting collective measures introduced under a climate policy scenario cannot distinguish between benefits accrued from CO2 reductions among sources of different types and at different locations. Location and sector dependencies are important factors that can be captured in an adjoint-based analysis of CO2 reduction co-benefits. The present study aims to quantify how the ancillary benefits of reducing criteria co-pollutants vary spatially and by sector. The adjoint of USEPA's CMAQ was applied to quantify the health benefits associated with emission reduction of criteria pollutants (NOX) in on-road mobile, Electric Generation Units (EGUs), and other select sectors on a location-by-location basis across the US and Canada. These health benefits are then converted to CO2 emission reduction co-benefits by accounting for source-specific emission rates of criteria pollutants in comparison to CO2. We integrate the results from the adjoint of CMAQ with emission estimates from 2011 NEI at the county level, and point source data from EPA's Air Markets Program Data and National Pollutant Release Inventory (NPRI) for Canada. Our preliminary results show that the monetized health benefits (due to averted chronic mortality) associated with reductions of 1 ton of CO2 emissions is up to 65/ton in Canada and 200/ton in US for mobile on-road sector. For EGU sources, co-benefits are estimated at up to 100/ton and 10/ton for the US and Canada respectively. For Canada, the calculated co-benefits through gaseous pollutants including NOx is larger than those through PM2.5 due to the official association between NO2 exposure and chronic mortality. Calculated co-benefits show a great deal of spatial variability across emission locations for different sectors and sub-sectors. Implications of such spatial variability in devising control policy options that effectively address both climate and air quality objectives will be discussed.

National Emissions Inventory (NEI), County-Level, US, 2008, 2011, 2014, EPA OAR, OAPQS

EPA Pesticide Factsheets

This US EPA Office of Air and Radiation, Office of Air Quality Planning and Standards, Air Quality Assessment Division, Air Quality Analysis Group (OAR, OAQPS, AQAD, AQAG) web service contains the following layers created from the 2008, 2011 and 2014 National Emissions Inventory (NEI): Carbon Monoxide (CO), Lead, Ammonia (NH3), Nitrogen Oxides (NOx), Particulate Matter 10 (PM10), Particulate Matter 2.5 (PM2.5), Sulfur Dioxide (SO2), Volatile Organic Compounds (VOC). Each of these layers conatin county level emissions for 2008, 2011, and 2014. Layers are drawn at all scales. The National Emission Inventory (NEI) is a comprehensive and detailed estimate of air emissions of criteria pollutants, criteria precursors, and hazardous air pollutants from air emissions sources. The NEI is released every three years based primarily upon data provided by State, Local, and Tribal air agencies for sources in their jurisdictions and supplemented by data developed by the US EPA. The NEI is built using the Emissions Inventory System (EIS) first to collect the data from State, Local, and Tribal air agencies and then to blend that data with other data sources.NEI point sources include emissions estimates for larger sources that are located at a fixed, stationary location. Point sources in the NEI include large industrial facilities and electric power plants, airports, and smaller industrial, non-industrial and commercial facilities. A small number of portable sources such as s

Relating to monitoring ion sources

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore; Bounds, John Alan

2002-01-01

The apparatus and method provide techniques for monitoring the position on alpha contamination in or on items or locations. The technique is particularly applicable to pipes, conduits and other locations to which access is difficult. The technique uses indirect monitoring of alpha emissions by detecting ions generated by the alpha emissions. The medium containing the ions is moved in a controlled manner frog in proximity with the item or location to the detecting unit and the signals achieved over time are used to generate alpha source position information.

40 CFR Table 3 to Subpart Zzzz of... - Subsequent Performance Tests

Code of Federal Regulations, 2011 CFR

2011-07-01

... reconstructed 2SLB stationary RICE with a brake horsepower > 500 located at major sources; new or reconstructed 4SLB stationary RICE with a brake horsepower ≥ 250 located at major sources; and new or reconstructed CI stationary RICE with a brake horsepower > 500 located at major sources Reduce CO emissions and not...

Quantifying methane emission from fugitive sources by combining tracer release and downwind measurements - a sensitivity analysis based on multiple field surveys.

PubMed

Mønster, Jacob G; Samuelsson, Jerker; Kjeldsen, Peter; Rella, Chris W; Scheutz, Charlotte

2014-08-01

Using a dual species methane/acetylene instrument based on cavity ring down spectroscopy (CRDS), the dynamic plume tracer dispersion method for quantifying the emission rate of methane was successfully tested in four measurement campaigns: (1) controlled methane and trace gas release with different trace gas configurations, (2) landfill with unknown emission source locations, (3) landfill with closely located emission sources, and (4) comparing with an Fourier transform infrared spectroscopy (FTIR) instrument using multiple trace gasses for source separation. The new real-time, high precision instrument can measure methane plumes more than 1.2 km away from small sources (about 5 kg h(-1)) in urban areas with a measurement frequency allowing plume crossing at normal driving speed. The method can be used for quantification of total methane emissions from diffuse area sources down to 1 kg per hour and can be used to quantify individual sources with the right choice of wind direction and road distance. The placement of the trace gas is important for obtaining correct quantification and uncertainty of up to 36% can be incurred when the trace gas is not co-located with the methane source. Measurements made at greater distances are less sensitive to errors in trace gas placement and model calculations showed an uncertainty of less than 5% in both urban and open-country for placing the trace gas 100 m from the source, when measurements were done more than 3 km away. Using the ratio of the integrated plume concentrations of tracer gas and methane gives the most reliable results for measurements at various distances to the source, compared to the ratio of the highest concentration in the plume, the direct concentration ratio and using a Gaussian plume model. Under suitable weather and road conditions, the CRDS system can quantify the emission from different sources located close to each other using only one kind of trace gas due to the high time resolution, while the FTIR system can measure multiple trace gasses but with a lower time resolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

40 CFR 63.6612 - By what date must I conduct the initial performance tests or other initial compliance...

Code of Federal Regulations, 2011 CFR

2011-07-01

... stationary RICE with a site rating of less than or equal to 500 brake HP located at a major source of HAP emissions or an existing stationary RICE located at an area source of HAP emissions? 63.6612 Section 63.6612... other initial compliance demonstrations if I own or operate an existing stationary RICE with a site...

40 CFR 63.6612 - By what date must I conduct the initial performance tests or other initial compliance...

Code of Federal Regulations, 2010 CFR

2010-07-01

... stationary RICE with a site rating of less than or equal to 500 brake HP located at a major source of HAP emissions or an existing stationary RICE located at an area source of HAP emissions? 63.6612 Section 63.6612... other initial compliance demonstrations if I own or operate an existing stationary RICE with a site...

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...

Multi-point laser ignition device

DOEpatents

McIntyre, Dustin L.; Woodruff, Steven D.

2017-01-17

A multi-point laser device comprising a plurality of optical pumping sources. Each optical pumping source is configured to create pumping excitation energy along a corresponding optical path directed through a high-reflectivity mirror and into substantially different locations within the laser media thereby producing atomic optical emissions at substantially different locations within the laser media and directed along a corresponding optical path of the optical pumping source. An output coupler and one or more output lenses are configured to produce a plurality of lasing events at substantially different times, locations or a combination thereof from the multiple atomic optical emissions produced at substantially different locations within the laser media. The laser media is a single continuous media, preferably grown on a single substrate.

Composition and source apportionment of PM1 at urban site Kanpur in India using PMF coupled with CBPF

NASA Astrophysics Data System (ADS)

Rai, Pragati; Chakraborty, Abhishek; Mandariya, Anil Kumar; Gupta, Tarun

2016-09-01

This study addresses the three major questions: (1) what are the emission sources of PM1 which are affecting the study area; (2) where do these emission sources come from; and (3) is there any temporal variation in the emission sources. To address these issues, two advanced statistical methods are described in this paper. Identification of emission sources was performed by EPA PMF (v 5.0) and to understand the temporal variability, sampling was done for three winter seasons 2008-09, 2009-10 and 2011-12 within Kanpur city. To identify the possible source directions, Conditional Bivariate Probability function (CBPF) was used. The average PM1 concentration was higher in 2008-09 followed by 2011-12 and 2009-10 winter seasons. 2008-09 winter showed sources such as secondary sources mixed with power plant emission (42.8%), industrial emission (32.3%), coal combustion, brick kilns and vehicular emission (13.2%) and residual oil combustion and road dust (11.7%). The major contributors during winter season 2009-10 were secondary sources (33.1%), biomass burning (23.3%), heavy oil combustion (13%), vehicular emission mixed with crustal dust (11.3%), leather tanning industries (10.3%), industrial emission (4%), coal combustion and brick kilns (3.4%) and solid waste burning and incineration (1.5%) compared to secondary sources mixed with biomass burning (42.3%), industrial emission and crustal dust (35.1%) and vehicular emission and brick kilns (22.6%) during 2011-12 winter season. PMF model revealed that secondary sources were the main contributors for all the three winter seasons followed by biomass burning and power plant emission. The results of CBPF analysis agreed well with the locations of known local point sources., e.g. in the case of industrial emissions, the maximum probability was in the direction between NES direction where almost all the major industries are located in and around Kanpur while in the opposite direction the probability of biomass burning was high due to a rural area in NWS direction.

Development of the Vista Methane Emissions Inventory for Southern California: A GIS-Based Approach for Mapping Methane Emissions

NASA Astrophysics Data System (ADS)

Carranza, V.; Frausto-Vicencio, I.; Rafiq, T.; Verhulst, K. R.; Hopkins, F. M.; Rao, P.; Duren, R. M.; Miller, C. E.

2016-12-01

Atmospheric methane (CH4) is the second most prevalent anthropogenic greenhouse gas. Improved estimates of CH4 emissions from cities is essential for carbon cycle science and climate mitigation efforts. Development of spatially-resolved carbon emissions data sets may offer significant advances in understanding and managing carbon emissions from cities. Urban CH4 emissions in particular require spatially resolved emission maps to help resolve uncertainties in the CH4 budget. This study presents a Geographic Information System (GIS)-based approach to mapping CH4 emissions using locations of infrastructure known to handle and emit methane. We constrain the spatial distribution of sources to the facility level for the major CH4 emitting sources in the South Coast Air Basin. GIS spatial modeling was combined with publicly available datasets to determine the distribution of potential CH4 sources. The datasets were processed and validated to ensure accuracy in the location of individual sources. This information was then used to develop the Vista emissions prior, which is a one-year long, spatially-resolved CH4 emissions estimate. Methane emissions were calculated and spatially allocated to produce 1 km x 1 km gridded CH4 emission map spanning the Los Angeles Basin. In future work, the Vista CH4 emissions prior will be compared with existing, coarser-resolution emissions estimates and will be evaluated in inverse modeling studies using atmospheric observations. The Vista CH4 emissions inventory presents the first detailed spatial maps of CH4 sources and emissions estimates in the Los Angeles Basin and is a critical step towards sectoral attribution of CH4 emissions at local to regional scales.

Study of acoustic emission during mechanical tests of large flight weight tank structure

NASA Technical Reports Server (NTRS)

Nakamura, Y.; Mccauley, B. O.; Veach, C. L.

1972-01-01

A polyphenylane oxide insulated, flight weight, subscale, aluminum tank was monitored for acoustic emissions during a proof test and during 100 cycles of environmental test simulating space flights. The use of a combination of frequency filtering and appropriate spatial filtering to reduce background noise was found to be sufficient to detect acoustic emission signals of relatively small intensity expected from subcritical crack growth in the structure. Several emission source locations were identified, including the one where a flaw was detected by post-test X-ray inspections. For most source locations, however, post-test inspections did not detect flaws; this was partially attributed to the higher sensitivity of the acoustic emission technique than any other currently available NDT method for detecting flaws.

77 FR 11974 - Approval and Promulgation of Implementation Plans; State of Iowa Regional Haze State...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-28

... and beyond. The modeling was based on PM Source Apportionment Technology (PSAT) for the Comprehensive... sources and the State adequately determined the apportionment of those pollutants from sources located... Class I areas caused by emissions of air pollutants from numerous sources located over a wide geographic...

Assessment of background particulate matter concentrations in small cities and rural locations--Prince George, Canada.

PubMed

Veira, Andreas; Jackson, Peter L; Ainslie, Bruce; Fudge, Dennis

2013-07-01

This study investigates the development and application of a simple method to calculate annual and seasonal PM2.5 and PM10 background concentrations in small cities and rural areas. The Low Pollution Sectors and Conditions (LPSC) method is based on existing measured long-term data sets and is designed for locations where particulate matter (PM) monitors are only influenced by local anthropogenic emission sources from particular wind sectors. The LPSC method combines the analysis of measured hourly meteorological data, PM concentrations, and geographical emission source distributions. PM background levels emerge from measured data for specific wind conditions, where air parcel trajectories measured at a monitoring station are assumed to have passed over geographic sectors with negligible local emissions. Seasonal and annual background levels were estimated for two monitoring stations in Prince George, Canada, and the method was also applied to four other small cities (Burns Lake, Houston, Quesnel, Smithers) in northern British Columbia. The analysis showed reasonable background concentrations for both monitoring stations in Prince George, whereas annual PM10 background concentrations at two of the other locations and PM2.5 background concentrations at one other location were implausibly high. For those locations where the LPSC method was successful, annual background levels ranged between 1.8 +/- 0.1 microg/m3 and 2.5 +/- 0.1 microg/m3 for PM2.5 and between 6.3 +/- 0.3 microg/m3 and 8.5 +/- 0.3 microg/m3 for PM10. Precipitation effects and patterns of seasonal variability in the estimated background concentrations were detectable for all locations where the method was successful. Overall the method was dependent on the configuration of local geography and sources with respect to the monitoring location, and may fail at some locations and under some conditions. Where applicable, the LPSC method can provide a fast and cost-efficient way to estimate background PM concentrations for small cities in sparsely populated regions like northern British Columbia. In rural areas like northern British Columbia, particulate matter (PM) monitoring stations are usually located close to emission sources and residential areas in order to assess the PM impact on human health. Thus there is a lack of accurate PM background concentration data that represent PM ambient concentrations in the absence of local emissions. The background calculation method developed in this study uses observed meteorological data as well as local source emission locations and provides annual, seasonal and precipitation-related PM background concentrations that are comparable to literature values for four out of six monitoring stations.

Acoustic emission source location in composite structure by Voronoi construction using geodesic curve evolution.

PubMed

Gangadharan, R; Prasanna, G; Bhat, M R; Murthy, C R L; Gopalakrishnan, S

2009-11-01

Conventional analytical/numerical methods employing triangulation technique are suitable for locating acoustic emission (AE) source in a planar structure without structural discontinuities. But these methods cannot be extended to structures with complicated geometry, and, also, the problem gets compounded if the material of the structure is anisotropic warranting complex analytical velocity models. A geodesic approach using Voronoi construction is proposed in this work to locate the AE source in a composite structure. The approach is based on the fact that the wave takes minimum energy path to travel from the source to any other point in the connected domain. The geodesics are computed on the meshed surface of the structure using graph theory based on Dijkstra's algorithm. By propagating the waves in reverse virtually from these sensors along the geodesic path and by locating the first intersection point of these waves, one can get the AE source location. In this work, the geodesic approach is shown more suitable for a practicable source location solution in a composite structure with arbitrary surface containing finite discontinuities. Experiments have been conducted on composite plate specimens of simple and complex geometry to validate this method.

40 CFR 63.6600 - What emission limitations and operating limitations must I meet if I own or operate a stationary...

Code of Federal Regulations, 2010 CFR

2010-07-01

... operating limitations must I meet if I own or operate a stationary RICE with a site rating of more than 500... RICE with a site rating of more than 500 brake HP located at a major source of HAP emissions... 4SRB stationary RICE with a site rating of more than 500 brake HP located at a major source of HAP...

40 CFR 63.6600 - What emission limitations and operating limitations must I meet if I own or operate a stationary...

Code of Federal Regulations, 2011 CFR

2011-07-01

... operating limitations must I meet if I own or operate a stationary RICE with a site rating of more than 500... RICE with a site rating of more than 500 brake HP located at a major source of HAP emissions... 4SRB stationary RICE with a site rating of more than 500 brake HP located at a major source of HAP...

40 CFR Table 2b to Subpart Zzzz of... - Operating Limitations for New and Reconstructed 2SLB and Compression Ignition Stationary RICE...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Reconstructed 2SLB and Compression Ignition Stationary RICE >500 HP Located at a Major Source of HAP Emissions, Existing Non-Emergency Compression Ignition Stationary RICE >500 HP, and New and Reconstructed 4SLB Burn Stationary RICE â¥250 HP Located at a Major Source of HAP Emissions 2b Table 2b to Subpart ZZZZ of Part 63...

Acoustic emission non-destructive testing of structures using source location techniques.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beattie, Alan G.

2013-09-01

The technology of acoustic emission (AE) testing has been advanced and used at Sandia for the past 40 years. AE has been used on structures including pressure vessels, fire bottles, wind turbines, gas wells, nuclear weapons, and solar collectors. This monograph begins with background topics in acoustics and instrumentation and then focuses on current acoustic emission technology. It covers the overall design and system setups for a test, with a wind turbine blade as the object. Test analysis is discussed with an emphasis on source location. Three test examples are presented, two on experimental wind turbine blades and one onmore » aircraft fire extinguisher bottles. Finally, the code for a FORTRAN source location program is given as an example of a working analysis program. Throughout the document, the stress is on actual testing of real structures, not on laboratory experiments.« less

The importance of source configuration in quantifying footprints of regional atmospheric sulphur deposition.

PubMed

Vieno, M; Dore, A J; Bealey, W J; Stevenson, D S; Sutton, M A

2010-01-15

An atmospheric transport-chemistry model is applied to investigate the effects of source configuration in simulating regional sulphur deposition footprints from elevated point sources. Dry and wet depositions of sulphur are calculated for each of the 69 largest point sources in the UK. Deposition contributions for each point source are calculated for 2003, as well as for a 2010 emissions scenario. The 2010 emissions scenario has been chosen to simulate the Gothenburg protocol emission scenario. Point source location is found to be a major driver of the dry/wet deposition ratio for each deposition footprint, with increased precipitation scavenging of SO(x) in hill areas resulting in a larger fraction of the emitted sulphur being deposited within the UK for sources located near these areas. This reduces exported transboundary pollution, but, associated with the occurrence of sensitive soils in hill areas, increases the domestic threat of soil acidification. The simulation of plume rise using individual stack parameters for each point source demonstrates a high sensitivity of SO(2) surface concentration to effective source height. This emphasises the importance of using site-specific information for each major stack, which is rarely included in regional atmospheric pollution models, due to the difficulty in obtaining the required input data. The simulations quantify how the fraction of emitted SO(x) exported from the UK increases with source magnitude, effective source height and easterly location. The modelled reduction in SO(x) emissions, between 2003 and 2010 resulted in a smaller fraction being exported, with the result that the reductions in SO(x) deposition to the UK are less than proportionate to the emission reduction. This non-linearity is associated with a relatively larger fraction of the SO(2) being converted to sulphate aerosol for the 2010 scenario, in the presence of ammonia. The effect results in less-than-proportional UK benefits of reducing in SO(2) emissions, together with greater-than-proportional benefits in reducing export of UK SO(2) emissions. Copyright 2009 Elsevier B.V. All rights reserved.

National Air Toxic Assessments (NATA) Results

EPA Pesticide Factsheets

The National Air Toxics Assessment was conducted by EPA in 2002 to assess air toxics emissions in order to identify and prioritize air toxics, emission source types and locations which are of greatest potential concern in terms of contributing to population risk. This data source provides downloadable information on emissions at the state, county and census tract level.

Acoustic emission monitoring system

DOEpatents

Romrell, Delwin M.

1977-07-05

Methods and apparatus for identifying the source location of acoustic emissions generated within an acoustically conductive medium. A plurality of acoustic receivers are communicably coupled to the surface of the medium at a corresponding number of spaced locations. The differences in the reception time of the respective sensors in response to a given acoustic event are measured among various sensor combinations prescribed by the monitoring mode employed. Acoustic reception response encountered subsequent to the reception by a predetermined number of the prescribed sensor combinations are inhibited from being communicated to the processing circuitry, while the time measurements obtained from the prescribed sensor combinations are translated into a position measurement representative of the location on the surface most proximate the source of the emission. The apparatus is programmable to function in six separate and five distinct operating modes employing either two, three or four sensory locations. In its preferred arrangement the apparatus of this invention will re-initiate a monitoring interval if the predetermined number of sensors do not respond to a particular emission within a given time period.

A novel multi-segment path analysis based on a heterogeneous velocity model for the localization of acoustic emission sources in complex propagation media.

PubMed

Gollob, Stephan; Kocur, Georg Karl; Schumacher, Thomas; Mhamdi, Lassaad; Vogel, Thomas

2017-02-01

In acoustic emission analysis, common source location algorithms assume, independently of the nature of the propagation medium, a straight (shortest) wave path between the source and the sensors. For heterogeneous media such as concrete, the wave travels in complex paths due to the interaction with the dissimilar material contents and with the possible geometrical and material irregularities present in these media. For instance, cracks and large air voids present in concrete influence significantly the way the wave travels, by causing wave path deviations. Neglecting these deviations by assuming straight paths can introduce significant errors to the source location results. In this paper, a novel source localization method called FastWay is proposed. It accounts, contrary to most available shortest path-based methods, for the different effects of material discontinuities (cracks and voids). FastWay, based on a heterogeneous velocity model, uses the fastest rather than the shortest travel paths between the source and each sensor. The method was evaluated both numerically and experimentally and the results from both evaluation tests show that, in general, FastWay was able to locate sources of acoustic emissions more accurately and reliably than the traditional source localization methods. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR Table 5 to Subpart Zzzz of... - Initial Compliance With Emission Limitations and Operating Limitations

Code of Federal Regulations, 2011 CFR

2011-07-01

... demonstrated initial compliance if . . . 1. New or reconstructed non-emergency 2SLB stationary RICE >500 HP located at a major source of HAP, new or reconstructed non-emergency 4SLB stationary RICE ≥250 HP located at a major source of HAP, non-emergency stationary CI RICE >500 HP located at a major source of HAP...

40 CFR Table 6 to Subpart Zzzz of... - Continuous Compliance With Emission Limitations, Operating Limitations, Work Practices, and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... major source of HAP a. Reduce CO emissions and using an oxidation catalyst, and using a CPMS i... RICE >500 HP located at a major source of HAP a. Reduce CO emissions and not using an oxidation... and using oxidation catalyst or NSCR i. Conducting semiannual performance tests for formaldehyde to...

40 CFR Table 6 to Subpart Zzzz of... - Continuous Compliance With Emission Limitations, Operating Limitations, Work Practices, and...

Code of Federal Regulations, 2011 CFR

2011-07-01

... major source of HAP a. Reduce CO emissions and using an oxidation catalyst, and using a CPMS i... RICE >500 HP located at a major source of HAP a. Reduce CO emissions and not using an oxidation... and using oxidation catalyst or NSCR i. Conducting semiannual performance tests for formaldehyde to...

Damage source identification of reinforced concrete structure using acoustic emission technique.

PubMed

Panjsetooni, Alireza; Bunnori, Norazura Muhamad; Vakili, Amir Hossein

2013-01-01

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring in loaded structures. This technique was employed for investigation process of damage in reinforced concrete (RC) frame specimens. A number of reinforced concrete RC frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data were analyzed using the AE source location analysis method. The results showed that AE technique is suitable to identify the sources location of damage in RC structures.

Damage Source Identification of Reinforced Concrete Structure Using Acoustic Emission Technique

PubMed Central

Panjsetooni, Alireza; Bunnori, Norazura Muhamad; Vakili, Amir Hossein

2013-01-01

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring in loaded structures. This technique was employed for investigation process of damage in reinforced concrete (RC) frame specimens. A number of reinforced concrete RC frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data were analyzed using the AE source location analysis method. The results showed that AE technique is suitable to identify the sources location of damage in RC structures. PMID:23997681

A Review of Advancements in Particulate Matter Sampling and Analysis and its Application to Identifying Source Impacts at Receptor Locations

EPA Science Inventory

Time-integrated (typically 24-hr) filter-based methods (historical methods) form the underpinning of our understanding of the fate, impact of source emissions at receptor locations (source impacts), and potential health and welfare effects of particulate matter (PM) in air. Over...

Benzene observations and source appointment in a region of oil and natural gas development

NASA Astrophysics Data System (ADS)

Halliday, Hannah Selene

Benzene is a primarily anthropogenic volatile organic compound (VOC) with a small number of well characterized sources. Atmospheric benzene affects human health and welfare, and low level exposure (< 0.5 ppbv) has been connected to measureable increases in cancer rates. Benzene measurements have been increasing in the region of oil and natural gas (O&NG) development located to the north of Denver. High time resolution measurements of VOCs were collected using a proton-transfer-reaction quadrupole mass spectrometry (PTR-QMS) instrument at the Platteville Atmospheric Observatory (PAO) in Colorado to investigate how O&NG development impacts air quality within the Wattenburg Gas Field (WGF) in the Denver-Julesburg Basin. The measurements were carried out in July and August 2014 as part of NASA's DISCOVER-AQ field campaign. The PTR-QMS data were supported by pressurized whole air canister samples and airborne vertical and horizontal surveys of VOCs. Unexpectedly high benzene mixing ratios were observed at PAO at ground level (mean benzene = 0.53 ppbv, maximum benzene = 29.3 ppbv), primarily at night (mean nighttime benzene = 0.73 ppbv). These high benzene levels were associated with southwesterly winds. The airborne measurements indicate that benzene originated from within the WGF, and typical source signatures detected in the canister samples implicate emissions from O&NG activities rather than urban vehicular emissions as primary benzene source. This conclusion is backed by a regional toluene-to-benzene ratio analysis which associated southerly flow with vehicular emissions from the Denver area. Weak benzene-to-CO correlations confirmed that traffic emissions were not responsible for the observed high benzene levels. Previous measurements at the Boulder Atmospheric Observatory (BAO) and our data obtained at PAO allow us to locate the source of benzene enhancements between the two atmospheric observatories. Fugitive emissions of benzene from O&NG operations in the Platteville area are discussed as the most likely causes of enhanced benzene levels at PAO. A limited information source attribution with the PAO dataset was completed using the EPA's positive matrix factorization (PMF) source receptor model. Six VOCs from the PTR-QMS measurement were used along with CO and NO for a total of eight chemical species. Six sources were identified in the PMF analysis: a primarily CO source, an aged vehicle emissions source, a diesel/compressed natural gas emissions source, a fugitive emissions source, and two sources that have the characteristics of a mix of fresh vehicle emissions and condensate fugitive emissions. 70% of the benzene measured at PAO on the PTR-QMS is attributed to fugitive emissions, primarily located to the SW of PAO. Comparing the PMF source attribution to source calculations done with a source array configured from the literature returns a contradictory result, with the expected sources indicting that aged vehicle emissions are the primary benzene source. However, analysis of the contradictory result indicates that the toluene to benzene ratio measured for PAO is much lower than the literature values, suggesting that the O&NG source emissions have a lower ratio of toluene to benzene than anticipated based on studies of other regions. Finally, we propose and investigate an alternative form of the source receptor model using a constrained optimization. Poor results of the proposed method are described with tests on a synthetic testing dataset, and further testing with the observation data from PAO indicate that the proposed method is not able to converge the best global solution to the system.

40 CFR 63.11454 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for.... (1) You must install each sensor of your monitoring system in a location that provides representative...

Characterizing and sourcing ambient PM2.5 over key emission regions in China II: Organic molecular markers and CMB modeling

NASA Astrophysics Data System (ADS)

Zhou, Jiabin; Xiong, Ying; Xing, Zhenyu; Deng, Junjun; Du, Ke

2017-08-01

From November 2012 to July 2013, a sampling campaign was completed for comprehensive characterization of PM2.5 over four key emission regions in China: Beijing-Tianjin-Hebei (BTH), Yangzi River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SB). A multi-method approach, adopting different analytical and receptor modeling methods, was employed to determine the relative abundances of region-specific air pollution constituents and contributions of emission sources. This paper is focused on organic molecular marker based source apportionment using chemical mass balance (CMB) receptor modeling. Analyses of the organic molecular markers revealed that vehicle emission, coal combustion, biomass burning, meat cooking and natural gas combustion were the major contributors to organic carbon (OC) in PM2.5. The vehicle emission dominated the sources contributing to OC in spring at four sampling sites. During wintertime, the coal combustion had highest contribution to OC at BTH site, while the major source contributing to OC at YRD and PRD sites was vehicle emission. In addition, the relative contributions of different emission sources to PM2.5 mass at a specific location site and in a specific season revealed seasonal and spatial variations across all four sampling locations. The largest contributor to PM2.5 mass was secondary sulfate (14-17%) in winter at the four sites. The vehicle emission was found to be the major source (14-21%) for PM2.5 mass at PRD site. The secondary ammonium has minor variation (4-5%) across the sites, confirming the influences of regional emission sources on these sites. The distinct patterns of seasonal and spatial variations of source apportionment observed in this study were consistent with the findings in our previous paper based upon water-soluble ions and carbonaceous fractions. This makes it essential for the local government to make season- and region-specific mitigation strategies for abating PM2.5 pollution in China.

A Jupiter Data Analysis Program (JDAP) research grant on wave accessibility and attributes

NASA Technical Reports Server (NTRS)

Calvert, Wynne

1987-01-01

For more than thirty years the intense decametric radio emissions from Jupiter (DAM) and the corresponding auroral kilometric radiation from the Earth (AKR) have remained major radio science mysteries. Part of the problem, aside from their inherent complexity, has been the difficulty of measuring their source location and emission properties from limited observations. Progress has been made on this problem by locating the source directly, i.e., by analysis of the faraday rotation observed with Voyager as the wave path crossed the Io plasma torus, and indirectly by comparing the peak frequencies of the decametric emission with that at the foot of the Io flux tube. Progress was also made on the general question of how the emissions originate by finding properties of both the AKR and DAM which would imply emission by natural radio lasing.

Identification of specific sources of airborne particles emitted from within a complex industrial (steelworks) site

NASA Astrophysics Data System (ADS)

Beddows, D. C. S.; Harrison, Roy M.

2018-06-01

A case study is provided of the development and application of methods to identify and quantify specific sources of emissions from within a large complex industrial site. Methods include directional analysis of concentrations, chemical source tracers and correlations with gaseous emissions. Extensive measurements of PM10, PM2.5, trace gases, particulate elements and single particle mass spectra were made at sites around the Port Talbot steelworks in 2012. By using wind direction data in conjunction with real-time or hourly-average pollutant concentration measurements, it has been possible to locate areas within the steelworks associated with enhanced pollutant emissions. Directional analysis highlights the Slag Handling area of the works as the most substantial source of elevated PM10 concentrations during the measurement period. Chemical analyses of air sampled from relevant wind directions is consistent with the anticipated composition of slags, as are single particle mass spectra. Elevated concentrations of PM10 are related to inverse distance from the Slag Handling area, and concentrations increase with increased wind speed, consistent with a wind-driven resuspension source. There also appears to be a lesser source associated with Sinter Plant emissions affecting PM10 concentrations at the Fire Station monitoring site. The results are compared with a ME2 study using some of the same data, and shown to give a clearer view of the location and characteristics of emission sources, including fugitive dusts.

Acoustic emission based damage localization in composites structures using Bayesian identification

NASA Astrophysics Data System (ADS)

Kundu, A.; Eaton, M. J.; Al-Jumali, S.; Sikdar, S.; Pullin, R.

2017-05-01

Acoustic emission based damage detection in composite structures is based on detection of ultra high frequency packets of acoustic waves emitted from damage sources (such as fibre breakage, fatigue fracture, amongst others) with a network of distributed sensors. This non-destructive monitoring scheme requires solving an inverse problem where the measured signals are linked back to the location of the source. This in turn enables rapid deployment of mitigative measures. The presence of significant amount of uncertainty associated with the operating conditions and measurements makes the problem of damage identification quite challenging. The uncertainties stem from the fact that the measured signals are affected by the irregular geometries, manufacturing imprecision, imperfect boundary conditions, existing damages/structural degradation, amongst others. This work aims to tackle these uncertainties within a framework of automated probabilistic damage detection. The method trains a probabilistic model of the parametrized input and output model of the acoustic emission system with experimental data to give probabilistic descriptors of damage locations. A response surface modelling the acoustic emission as a function of parametrized damage signals collected from sensors would be calibrated with a training dataset using Bayesian inference. This is used to deduce damage locations in the online monitoring phase. During online monitoring, the spatially correlated time data is utilized in conjunction with the calibrated acoustic emissions model to infer the probabilistic description of the acoustic emission source within a hierarchical Bayesian inference framework. The methodology is tested on a composite structure consisting of carbon fibre panel with stiffeners and damage source behaviour has been experimentally simulated using standard H-N sources. The methodology presented in this study would be applicable in the current form to structural damage detection under varying operational loads and would be investigated in future studies.

Effect of low emission sources on air quality in Cracow

DOE Office of Scientific and Technical Information (OSTI.GOV)

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, butmore » the location of the source and especially packing density of the sources must decide the priority of upgrading actions.« less

Inverse modeling and mapping US air quality influences of inorganic PM2.5 precursor emissions using the adjoint of GEOS-Chem

NASA Astrophysics Data System (ADS)

Henze, D. K.; Seinfeld, J. H.; Shindell, D. T.

2009-08-01

Influences of specific sources of inorganic PM2.5 on peak and ambient aerosol concentrations in the US are evaluated using a combination of inverse modeling and sensitivity analysis. First, sulfate and nitrate aerosol measurements from the IMPROVE network are assimilated using the four-dimensional variational (4D-Var) method into the GEOS-Chem chemical transport model in order to constrain emissions estimates in four separate month-long inversions (one per season). Of the precursor emissions, these observations primarily constrain ammonia (NH3). While the net result is a decrease in estimated US~NH3 emissions relative to the original inventory, there is considerable variability in adjustments made to NH3 emissions in different locations, seasons and source sectors, such as focused decreases in the midwest during July, broad decreases throughout the US~in January, increases in eastern coastal areas in April, and an effective redistribution of emissions from natural to anthropogenic sources. Implementing these constrained emissions, the adjoint model is applied to quantify the influences of emissions on representative PM2.5 air quality metrics within the US. The resulting sensitivity maps display a wide range of spatial, sectoral and seasonal variability in the susceptibility of the air quality metrics to absolute emissions changes and the effectiveness of incremental emissions controls of specific source sectors. NH3 emissions near sources of sulfur oxides (SOx) are estimated to most influence peak inorganic PM2.5 levels in the East; thus, the most effective controls of NH3 emissions are often disjoint from locations of peak NH3 emissions. Controls of emissions from industrial sectors of SOx and NOx are estimated to be more effective than surface emissions, and changes to NH3 emissions in regions dominated by natural sources are disproportionately more effective than regions dominated by anthropogenic sources. NOx controls are most effective in northern states in October; in January, SOx controls may be counterproductive. When considering ambient inorganic PM2.5 concentrations, intercontinental influences are small, though transboundary influences within North America are significant, with SOx emissions from surface sources in Mexico contributing almost a fourth of the total influence from this sector.

Inverse modeling and mapping US air quality influences of inorganic PM2.5 precursor emissions using the adjoint of GEOS-Chem

NASA Astrophysics Data System (ADS)

Henze, D. K.; Seinfeld, J. H.; Shindell, D. T.

2008-08-01

Influences of specific sources of inorganic PM2.5 on peak and ambient aerosol concentrations in the US are evaluated using a combination of inverse modeling and sensitivity analysis. First, sulfate and nitrate aerosol measurements from the IMPROVE network are assimilated using the four-dimensional variational (4D-Var) method into the GEOS-Chem chemical transport model in order to constrain emissions estimates in four separate month-long inversions (one per season). Of the precursor emissions, these observations primarily constrain ammonia (NH3). While the net result is a decrease in estimated US NH3 emissions relative to the original inventory, there is considerable variability in adjustments made to NH3 emissions in different locations, seasons and source sectors, such as focused decreases in the midwest during July, broad decreases throughout the US~in January, increases in eastern coastal areas in April, and an effective redistribution of emissions from natural to anthropogenic sources. Implementing these constrained emissions, the adjoint model is applied to quantify the influences of emissions on representative PM2.5 air quality metrics within the US. The resulting sensitivity maps display a wide range of spatial, sectoral and seasonal variability in the susceptibility of the air quality metrics to absolute emissions changes and the effectiveness of incremental emissions controls of specific source sectors. NH3 emissions near sources of sulfur oxides (SOx) are estimated to most influence peak inorganic PM2.5 levels in the East; thus, the most effective controls of NH3 emissions are often disjoint from locations of peak NH3 emissions. Controls of emissions from industrial sectors of SOx and NOx are estimated to be more effective than surface emissions, and changes to NH3 emissions in regions dominated by natural sources are disproportionately more effective than regions dominated by anthropogenic sources. NOx controls are most effective in northern states in October; in January, SOx controls may be counterproductive. When considering ambient inorganic PM2.5 concentrations, intercontinental influences are small, though transboundary influences within North America are significant, with SOx emissions from surface sources in Mexico contributing almost a fourth of the total influence from this sector.

40 CFR 63.6603 - What emission limitations and operating limitations must I meet if I own or operate an existing...

Code of Federal Regulations, 2010 CFR

2010-07-01

... operating limitations must I meet if I own or operate an existing stationary CI RICE located at an area... and operating limitations must I meet if I own or operate an existing stationary CI RICE located at an... stationary CI RICE located at an area source of HAP emissions, you must comply with the requirements in Table...

Reported emissions of organic gases are not consistent with observations

PubMed Central

Henry, Ronald C.; Spiegelman, Clifford H.; Collins, John F.; Park, EunSug

1997-01-01

Regulatory agencies and photochemical models of ozone rely on self-reported industrial emission rates of organic gases. Incorrect self-reported emissions can severely impact on air quality models and regulatory decisions. We compared self-reported emissions of organic gases in Houston, Texas, to measurements at a receptor site near the Houston ship channel, a major petrochemical complex. We analyzed hourly observations of total nonmethane organic carbon and 54 hydrocarbon compounds from C-2 to C-9 for the period June through November, 1993. We were able to demonstrate severe inconsistencies between reported emissions and major sources as derived from the data using a multivariate receptor model. The composition and the location of the sources as deduced from the data are not consistent with the reported industrial emissions. On the other hand, our observationally based methods did correctly identify the location and composition of a relatively small nearby chemical plant. This paper provides strong empirical evidence that regulatory agencies and photochemical models are making predictions based on inaccurate industrial emissions. PMID:11038551

Characterizing the detectability of emission signals from a North Korean nuclear detonation

DOE PAGES

Werth, David; Buckley, Robert

2017-02-01

Here, the detectability of emission sources, defined by a low-level of mixing with other sources, was estimated for various locations surrounding the Sea of Japan, including a site within North Korea. A high-resolution meteorological model coupled to a dispersion model was used to simulate plume dynamics for four periods, and two metrics of airborne plume mixing were calculated for each source. While emissions from several known sources in this area tended to blend with others while dispersing downwind, the North Korean plume often remained relatively distinct, thereby making it potentially easier to unambiguously ‘backtrack’ it to its source.

Development of a composite line source emission model for traffic interrupted microenvironments and its application in particle number emissions at a bus station

NASA Astrophysics Data System (ADS)

Wang, Lina; Jayaratne, Rohan; Heuff, Darlene; Morawska, Lidia

A composite line source emission (CLSE) model was developed to specifically quantify exposure levels and describe the spatial variability of vehicle emissions in traffic interrupted microenvironments. This model took into account the complexity of vehicle movements in the queue, as well as different emission rates relevant to various driving conditions (cruise, decelerate, idle and accelerate), and it utilised multi-representative segments to capture the accurate emission distribution for real vehicle flow. Hence, this model was able to quickly quantify the time spent in each segment within the considered zone, as well as the composition and position of the requisite segments based on the vehicle fleet information, which not only helped to quantify the enhanced emissions at critical locations, but it also helped to define the emission source distribution of the disrupted steady flow for further dispersion modelling. The model then was applied to estimate particle number emissions at a bi-directional bus station used by diesel and compressed natural gas fuelled buses. It was found that the acceleration distance was of critical importance when estimating particle number emission, since the highest emissions occurred in sections where most of the buses were accelerating and no significant increases were observed at locations where they idled. It was also shown that emissions at the front end of the platform were 43 times greater than at the rear of the platform. Although the CLSE model is intended to be applied in traffic management and transport analysis systems for the evaluation of exposure, as well as the simulation of vehicle emissions in traffic interrupted microenvironments, the bus station model can also be used for the input of initial source definitions in future dispersion models.

Toward a probabilistic acoustic emission source location algorithm: A Bayesian approach

NASA Astrophysics Data System (ADS)

Schumacher, Thomas; Straub, Daniel; Higgins, Christopher

2012-09-01

Acoustic emissions (AE) are stress waves initiated by sudden strain releases within a solid body. These can be caused by internal mechanisms such as crack opening or propagation, crushing, or rubbing of crack surfaces. One application for the AE technique in the field of Structural Engineering is Structural Health Monitoring (SHM). With piezo-electric sensors mounted to the surface of the structure, stress waves can be detected, recorded, and stored for later analysis. An important step in quantitative AE analysis is the estimation of the stress wave source locations. Commonly, source location results are presented in a rather deterministic manner as spatial and temporal points, excluding information about uncertainties and errors. Due to variability in the material properties and uncertainty in the mathematical model, measures of uncertainty are needed beyond best-fit point solutions for source locations. This paper introduces a novel holistic framework for the development of a probabilistic source location algorithm. Bayesian analysis methods with Markov Chain Monte Carlo (MCMC) simulation are employed where all source location parameters are described with posterior probability density functions (PDFs). The proposed methodology is applied to an example employing data collected from a realistic section of a reinforced concrete bridge column. The selected approach is general and has the advantage that it can be extended and refined efficiently. Results are discussed and future steps to improve the algorithm are suggested.

40 CFR 63.11436 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Clay Ceramics... subpart cover? (a) This subpart applies to any existing or new affected source located at a clay ceramics... glazed ceramic ware located at a clay ceramics manufacturing facility. (c) An affected source is existing...

Direction-finding measurements of type 3 radio bursts out of the ecliptic plane

NASA Technical Reports Server (NTRS)

Baumback, M. M.; Kurth, W. S.; Gurnett, D. A.

1975-01-01

Direction-finding measurements with the plasma wave experiments on the HAWKEYE 1 and IMP 8 satellites are used to find the source locations of type 3 solar radio bursts in heliocentric latitude and longitude in a frequency range from 31.1 kHz to 500 kHz. Using an empirical model for the emission frequency as a function of radial distance from the sun the three-dimensional trajectory of the type 3 radio source can be determined from direction-finding measurements at different frequencies. Since the electrons which produce these radio emissions follow the magnetic field lines from the sun these measurements provide information on the three-dimensional structure of the magnetic field in the solar wind. The source locations projected into the ecliptic plane follow an Archimedian spiral. Perpendicular to the ecliptic plane the source locations usually follow a constant heliocentric latitude. With direction-finding measurements of this type it is also possible to determine the source size from the modulation factor of the received signals.

Future-year ozone prediction for the United States using updated models and inputs.

PubMed

Collet, Susan; Kidokoro, Toru; Karamchandani, Prakash; Shah, Tejas; Jung, Jaegun

2017-08-01

The relationship between emission reductions and changes in ozone can be studied using photochemical grid models. These models are updated with new information as it becomes available. The primary objective of this study was to update the previous Collet et al. studies by using the most up-to-date (at the time the study was done) modeling emission tools, inventories, and meteorology available to conduct ozone source attribution and sensitivity studies. Results show future-year, 2030, design values for 8-hr ozone concentrations were lower than base-year values, 2011. The ozone source attribution results for selected cities showed that boundary conditions were the dominant contributors to ozone concentrations at the western U.S. locations, and were important for many of the eastern U.S. Point sources were generally more important in the eastern United States than in the western United States. The contributions of on-road mobile emissions were less than 5 ppb at a majority of the cities selected for analysis. The higher-order decoupled direct method (HDDM) results showed that in most of the locations selected for analysis, NOx emission reductions were more effective than VOC emission reductions in reducing ozone levels. The source attribution results from this study provide useful information on the important source categories and provide some initial guidance on future emission reduction strategies. The relationship between emission reductions and changes in ozone can be studied using photochemical grid models, which are updated with new available information. This study was to update the previous Collet et al. studies by using the most current, at the time the study was done, models and inventory to conduct ozone source attribution and sensitivity studies. The source attribution results from this study provide useful information on the important source categories and provide some initial guidance on future emission reduction strategies.

40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed Spark Ignition 4SRB Stationary RICE...

Code of Federal Regulations, 2012 CFR

2012-07-01

..., and Reconstructed Spark Ignition 4SRB Stationary RICE >500 HP Located at a Major Source of HAP Emissions and Existing Spark Ignition 4SRB Stationary RICE >500 HP Located at an Area Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition 4SRB Stationary RICE >500 HP Located at a...

40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed Spark Ignition 4SRB Stationary RICE...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., New, and Reconstructed Spark Ignition 4SRB Stationary RICE >500 HP Located at a Major Source of HAP Emissions and Existing Spark Ignition 4SRB Stationary RICE >500 HP Located at an Area Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition 4SRB Stationary RICE >500 HP Located at a...

Contributions of projected land use to global radiative forcing ascribed to local sources

NASA Astrophysics Data System (ADS)

Ward, D. S.; Mahowald, N. M.; Kloster, S.

2013-12-01

With global demand for food expected to dramatically increase and put additional pressures on natural lands, there is a need to understand the environmental impacts of land use and land cover change (LULCC). Previous studies have shown that the magnitude and even the sign of the radiative forcing (RF) of biogeophysical effects from LULCC depends on the latitude and forest ecology of the disturbed region. Here we ascribe the contributions to the global RF by land-use related anthropogenic activities to their local sources, organized on a grid of 1.9 degrees latitude by 2.5 degrees longitude. We use RF estimates for the year 2100, using five future LULCC projections, computed from simulations with the National Center for Atmospheric Research Community Land Model and Community Atmosphere Models and additional offline analyses. Our definition of the LULCC RF includes changes to terrestrial carbon storage, methane and nitrous oxide emissions, atmospheric chemistry, aerosol emissions, and surface albedo. We ascribe the RF to gridded locations based on LULCC-related emissions of relevant trace gases and aerosols, including emissions from fires. We find that the largest contributions to the global RF in year 2100 from LULCC originate in the tropics for all future scenarios. In fact, LULCC is the largest tropical source of anthropogenic RF. The LULCC RF in the tropics is dominated by emissions of CO2 from deforestation and methane emissions from livestock and soils. Land surface albedo change is rarely the dominant forcing agent in any of the future LULCC projections, at any location. By combining the five future scenarios we find that deforested area at a specific tropical location can be used to predict the contribution to global RF from LULCC at that location (the relationship does not hold as well in the extratropics). This information could support global efforts like REDD (Reducing Emissions from Deforestation and Forest Degradation), that aim to reduce greenhouse gas emissions from land use, by helping to optimize their effectiveness for climate change mitigation.

Source Regions of the Type II Radio Burst Observed During a CME-CME Interaction on 2013 May 22

NASA Technical Reports Server (NTRS)

Makela, P.; Gopalswamy, N.; Reiner, M. J.; Akiyama, S.; Krupar, V.

2016-01-01

We report on our study of radio source regions during the type II radio burst on 2013 May 22 based on direction finding analysis of the Wind/WAVES and STEREO/WAVES (SWAVES) radio observations at decameter-hectometric wavelengths. The type II emission showed an enhancement that coincided with the interaction of two coronal mass ejections (CMEs) launched in sequence along closely spaced trajectories. The triangulation of the SWAVES source directions posited the ecliptic projections of the radio sources near the line connecting the Sun and the STEREO-A spacecraft. The WAVES and SWAVES source directions revealed shifts in the latitude of the radio source, indicating that the spatial location of the dominant source of the type II emission varies during the CME-CME interaction. The WAVES source directions close to 1MHz frequencies matched the location of the leading edge of the primary CME seen in the images of the LASCO/C3 coronagraph. This correspondence of spatial locations at both wavelengths confirms that the CME-CME interaction region is the source of the type II enhancement. Comparison of radio and white-light observations also showed that at lower frequencies scattering significantly affects radio wave propagation.

Method and apparatus for calibrating a particle emissions monitor

DOEpatents

Flower, W.L.; Renzi, R.F.

1998-07-07

The invention discloses a method and apparatus for calibrating particulate emissions monitors, in particular, sampling probes, and in general, without removing the instrument from the system being monitored. A source of one or more specific metals in aerosol (either solid or liquid) or vapor form is housed in the instrument. The calibration operation is initiated by moving a focusing lens, used to focus a light beam onto an analysis location and collect the output light response, from an operating position to a calibration position such that the focal point of the focusing lens is now within a calibration stream issuing from a calibration source. The output light response from the calibration stream can be compared to that derived from an analysis location in the operating position to more accurately monitor emissions within the emissions flow stream. 6 figs.

Method and apparatus for calibrating a particle emissions monitor

DOEpatents

Flower, William L.; Renzi, Ronald F.

1998-07-07

The instant invention discloses method and apparatus for calibrating particulate emissions monitors, in particular, and sampling probes, in general, without removing the instrument from the system being monitored. A source of one or more specific metals in aerosol (either solid or liquid) or vapor form is housed in the instrument. The calibration operation is initiated by moving a focusing lens, used to focus a light beam onto an analysis location and collect the output light response, from an operating position to a calibration position such that the focal point of the focusing lens is now within a calibration stream issuing from a calibration source. The output light response from the calibration stream can be compared to that derived from an analysis location in the operating position to more accurately monitor emissions within the emissions flow stream.

Measurement of Jovian decametric Io-related source location and beam shape

NASA Technical Reports Server (NTRS)

Maeda, K.; Carr, T. D.

1992-01-01

The paper presents new information on the locations of the Io-related sources A and C (i.e., Io-A and Io-C) and on the shapes of their emission beams on the basis of measurements of the Jovian decametric activity that was recorded by Voyager 1 and 2. In two instances, the same dynamic spectral arc event in the recorded data of the two spacecraft was recorded, providing in each case an opportunity to observe the same emission beam over a wide range of frequencies from two considerably different directions. The propagation-corrected centroid times of each of the Voyager-1 arcs are found to be coincident with those of the corresponding Voyager-2 arc in a particular frequency range, but not at other frequencies. The hypothesis that emission beams are in the form of thin, almost conical sheets, the cone opening angle decreasing with increasing frequency, is confirmed. It is demonstrated that both the Io-A and Io-C sources were located near the northern foot of the magnetic flux tube that was connected to Io.

Aerosol Health Impact Source Attribution Studies with the CMAQ Adjoint Air Quality Model

NASA Astrophysics Data System (ADS)

Turner, M. D.

Fine particulate matter (PM2.5) is an air pollutant consisting of a mixture of solid and liquid particles suspended in the atmosphere. Knowledge of the sources and distributions of PM2.5 is important for many reasons, two of which are that PM2.5 has an adverse effect on human health and also an effect on climate change. Recent studies have suggested that health benefits resulting from a unit decrease in black carbon (BC) are four to nine times larger than benefits resulting from an equivalent change in PM2.5 mass. The goal of this thesis is to quantify the role of emissions from different sectors and different locations in governing the total health impacts, risk, and maximum individual risk of exposure to BC both nationally and regionally in the US. We develop and use the CMAQ adjoint model to quantify the role of emissions from all modeled sectors, times, and locations on premature deaths attributed to exposure to BC. From a national analysis, we find that damages resulting from anthropogenic emissions of BC are strongly correlated with population and premature death. However, we find little correlation between damages and emission magnitude, suggesting that controls on the largest emissions may not be the most efficient means of reducing damages resulting from BC emissions. Rather, the best proxy for locations with damaging BC emissions is locations where premature deaths occur. Onroad diesel and nonroad vehicle emissions are the largest contributors to premature deaths attributed to exposure to BC, while onroad gasoline emissions cause the highest deaths per amount emitted. Additionally, emissions in fall and winter contribute to more premature deaths (and more per amount emitted) than emissions in spring and summer. From a regional analysis, we find that emissions from outside each of six urban areas account for 7% to 27% of the premature deaths attributed to exposure to BC within the region. 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 of reductions to onroad diesel sectors, and provide similar benefits per unit of reduced emission to that of onroad gasoline emissions in the region. While 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. From an analysis of the health impacts of BC emissions on specific demographic populations, we find that emissions in the southern half of the US tend to disproportionally affect persons with a below high school education and persons below 50% of the poverty level. Analysis of national risk (independent of population and mortality rates) shows that the largest risks are associated with drier climates, due to the increased atmospheric lifetime resulting from less wet removal of aerosols. Lastly, analysis of the impacts of BC emissions on maximum individual risk shows that contributions to maximum individual risk are weakly to strongly correlated with emissions (R2 ranging from 0.23 in the San Joaquin Valley to 0.93 in the Dallas region). Overall, this thesis shows the value of high-resolution, adjoint-based source attribution studies for determining the locations, seasons, and sectors that have the greatest estimated impact on human health in air quality models.

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Werth, David; Buckley, Robert

Here, the detectability of emission sources, defined by a low-level of mixing with other sources, was estimated for various locations surrounding the Sea of Japan, including a site within North Korea. A high-resolution meteorological model coupled to a dispersion model was used to simulate plume dynamics for four periods, and two metrics of airborne plume mixing were calculated for each source. While emissions from several known sources in this area tended to blend with others while dispersing downwind, the North Korean plume often remained relatively distinct, thereby making it potentially easier to unambiguously ‘backtrack’ it to its source.

IMPACT OF EMISSION REDUCTIONS ON EXPOSURES AND EXPOSURE DISTRIBUTIONS: APPLICATION OF A GEOGRAPHIC EXPOSURE MODEL

EPA Science Inventory

Anticipated results include the following. (1) We will estimate intake fraction (i.e., the fraction of emissions that are inhaled) for major source categories, over time, and by spatial location. Higher intake fraction indicates a greater exposure reduction per emission reduct...

HIGH METHANE EMISSIONS FROM A MID-LATITUDE AGRICULTURAL RESERVOIR

EPA Science Inventory

To assess the magnitude of methane (CH4) emissions from reservoirs in agricultural regions, we measured CH4 emission rates from William H. Harsha Lake, located in southwestern Ohio, USA, over a thirteen month period. The reservoir was a strong source of CH4¬ throughout the year,...

National Emission Standards for Hazardous Air Pollutants (NESHAP) for Lime Manufacturing Background Information Document (BID): Public Comments and Responses

EPA Pesticide Factsheets

On December 20, 2002, the EPA proposed national emission standards for HAP emissions from lime manufacturing plants located at major source facilities (67 FR 78046). Summaries of the comments, and the EPA's responses, are presented in this BID.

Eagle Ford Shale BTEX and NOx concentrations are dominated by oil and gas industry emissions

NASA Astrophysics Data System (ADS)

Schade, G. W.; Roest, G. S.

2017-12-01

US shale oil and gas exploration has been identified as a major source of greenhouse gases and non-methane hydrocarbon (NMHC) emissions to the atmosphere. Here, we present a detailed analysis of 2015 air quality data acquired by the Texas Commission on Environmental Quality (TCEQ) at an air quality monitoring station in Karnes County, TX, central to Texas' Eagle Ford shale area. Data include time series of hourly measured NMHCs, nitrogen oxides (NOx), and hydrogen sulfide (H2S) alongside meteorological measurements. The monitor was located in Karnes City, and thus affected by various anthropogenic emissions, including traffic and oil and gas exploration sources. Highest mixing ratios measured in 2015 included nearly 1 ppm ethane, 0.8 ppm propane, alongside 4 ppb benzene. A least-squares minimization non-negative matrix factorization (NMF) analysis, tested with prior data analyzed using standard PMF-2 software, showed six major emission sources: an evaporative and fugitive source, a flaring source, a traffic source, an oil field source, a diesel source, and an industrial manufacturing source, together accounting for more than 95% of data set variability, and interpreted using NMHC composition and meteorological data. Factor scores strongly suggest that NOx emissions are dominated by flaring and associated sources, such as diesel compressor engines, likely at midstream facilities, while traffic in this rural area is a minor NOx source. The results support, but exceed existing 2012 emission inventories estimating that local traffic emitted seven times fewer NOx than oil and gas exploration sources in the county. Sources of air toxics such as the BTEX compounds are also dominated by oil and gas exploration sources, but are more equally distributed between the associated factors. Benzene abundance is only 20-40% associated with traffic sources, and may thus be 2.5-5 times higher now than prior to the shale boom in this area. Although the monitor was located relatively far from oil and gas exploration sources, these results suggest that exposure to air toxics in this rural population has likely increased manifold since the start of the regional shale boom in 2008.

Aerosol Microphysics and Radiation Integration

DTIC Science & Technology

2003-09-30

656-4769 email: reidj@nrlmry.navy.mil Award Number: N0001403WX20570 http://www.nrlmry.navy.mil/aerosol/ http://www.nrlmry.navy.mil/ flambe ...Fire Locating and Modeling of Burning Emissions ( FLAMBE ) project, which also provides NAAPS with a real-time biomass burning source function. In...Locating and Modeling of Burning Emissions ( FLAMBE ) project are currently being utilized by internet community, Air quality/human health research

40 CFR Table 1a to Subpart Zzzz of... - Emission Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a... emission limitations for existing, new and reconstructed 4SRB stationary RICE at 100 percent load plus or...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

Source identification and apportionment of halogenated compounds observed at a remote site in East Asia.

PubMed

Li, Shanlan; Kim, Jooil; Park, Sunyoung; Kim, Seung-Kyu; Park, Mi-Kyung; Mühle, Jens; Lee, Gangwoong; Lee, Meehye; Jo, Chun Ok; Kim, Kyung-Ryul

2014-01-01

The sources of halogenated compounds in East Asia associated with stratospheric ozone depletion and climate change are relatively poorly understood. High-precision in situ measurements of 18 halogenated compounds and carbonyl sulfide (COS) made at Gosan, Jeju Island, Korea, from November 2007 to December 2011 were analyzed by a positive matrix factorization (PMF). Seven major industrial sources were identified from the enhanced concentrations of halogenated compounds observed at Gosan and corresponding concentration-based source contributions were also suggested: primary aluminum production explaining 37% of total concentration enhancements, solvent usage of which source apportionment is 25%, fugitive emissions from HCFC/HFC production with 11%, refrigerant replacements (9%), semiconductor/electronics industry (9%), foam blowing agents (6%), and fumigation (3%). Statistical trajectory analysis was applied to specify the potential emission regions for seven sources using back trajectories. Primary aluminum production, solvent usage and fugitive emission sources were mainly contributed by China. Semiconductor/electronics sources were dominantly located in Korea. Refrigerant replacement, fumigation and foam blowing agent sources were spread throughout East Asian countries. The specified potential source regions are consistent with country-based consumptions and emission patterns, verifying the PMF analysis results. The industry-based emission sources of halogenated compounds identified in this study help improve our understanding of the East Asian countries' industrial contributions to halogenated compound emissions.

Controlling VOCs and odor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zmuda, J.

1994-07-01

Few environmental issues attract more attention than odor emissions. The odor source can quickly be identified, coming under immediate public scrutiny. Often, odor is not merely a public nuisance problem but can be indicative of volatile organic compound (VOC) control needs at the facility. In some cases, odor-producing compounds are VOCs regulated under different sections of federal, state or local law. Specific requirements for VOC or odor control depend on many factors, including the source and nature of the emissions, the quantity of emissions and the location of the facility. Many states impose specific odor-control requirements, in addition to themore » regulations of the Clean Air Act Amendments of 1990 (CAAA), under which odor-causing emissions may be regulated under Titles 1 and/or 3. Under Title 1, the non-attainment title, facilities located in major metropolitan areas not in attainment of the National Ambient Air Quality Standards (NAAQS) for ozone likely will be required to reduce emissions of VOCs.« less

40 CFR Table 3 to Subpart Zzzz of... - Subsequent Performance Tests

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Existing non-emergency, non-black start CI stationary RICE with a brake horsepower >500 that are not... 4SLB stationary RICE with a brake horsepower >500 located at major sources and new or reconstructed CI stationary RICE with a brake horsepower >500 located at major sources Reduce CO emissions and not using a...

Uncertainties and implications of applying aggregated data for spatial modelling of atmospheric ammonia emissions.

PubMed

Hellsten, S; Dragosits, U; Place, C J; Dore, A J; Tang, Y S; Sutton, M A

2018-05-09

Ammonia emissions vary greatly at a local scale, and effects (eutrophication, acidification) occur primarily close to sources. Therefore it is important that spatially distributed emission estimates are located as accurately as possible. The main source of ammonia emissions is agriculture, and therefore agricultural survey statistics are the most important input data to an ammonia emission inventory alongside per activity estimates of emission potential. In the UK, agricultural statistics are collected at farm level, but are aggregated to parish level, NUTS-3 level or regular grid resolution for distribution to users. In this study, the Modifiable Areal Unit Problem (MAUP), associated with such amalgamation, is investigated in the context of assessing the spatial distribution of ammonia sources for emission inventories. England was used as a test area to study the effects of the MAUP. Agricultural survey data at farm level (point data) were obtained under license and amalgamated to different areal units or zones: regular 1-km, 5-km, 10-km grids and parish level, before they were imported into the emission model. The results of using the survey data at different levels of amalgamation were assessed to estimate the effects of the MAUP on the spatial inventory. The analysis showed that the size and shape of aggregation zones applied to the farm-level agricultural statistics strongly affect the location of the emissions estimated by the model. If the zones are too small, this may result in false emission "hot spots", i.e., artificially high emission values that are in reality not confined to the zone to which they are allocated. Conversely, if the zones are too large, detail may be lost and emissions smoothed out, which may give a false impression of the spatial patterns and magnitude of emissions in those zones. The results of the study indicate that the MAUP has a significant effect on the location and local magnitude of emissions in spatial inventories where amalgamated, zonal data are used. Copyright © 2018 Elsevier Ltd. All rights reserved.

Differences Between Magnitudes and Health Impacts of BC ...

EPA Pesticide Factsheets

Recent assessments have analyzed the health impacts of PM2.5 from emissions from different locations and sectors using simplified or reduced-form air quality models. Here we present an alternative approach using the adjoint of the Community Multiscale Air Quality (CMAQ) model, which provides source–receptor relationships at highly resolved sectoral, spatial, and temporal scales. While damage resulting from anthropogenic emissions of BC is strongly correlated with population and premature death, we found little correlation between damage and emission magnitude, suggesting that controls on the largest emissions may not be the most efficient means of reducing damage resulting from anthropogenic BC emissions. Rather, the best proxy for locations with damaging BC emissions is locations where premature deaths occur. Onroad diesel and nonroad vehicle emissions are the largest contributors to premature deaths attributed to exposure to BC, while onroad gasoline emissions cause the highest deaths per amount emitted. Emissions in fall and winter contribute to more premature deaths (and more per amount emitted) than emissions in spring and summer. Overall, these results show the value of the high-resolution source attribution for determining the locations, seasons, and sectors for which BC emission controls have the most effective health benefits. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mis

SOURCE REGIONS OF THE TYPE II RADIO BURST OBSERVED DURING A CME–CME INTERACTION ON 2013 MAY 22

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mäkelä, P.; Reiner, M. J.; Akiyama, S.

2016-08-20

We report on our study of radio source regions during the type II radio burst on 2013 May 22 based on direction-finding analysis of the Wind /WAVES and STEREO /WAVES (SWAVES) radio observations at decameter–hectometric wavelengths. The type II emission showed an enhancement that coincided with the interaction of two coronal mass ejections (CMEs) launched in sequence along closely spaced trajectories. The triangulation of the SWAVES source directions posited the ecliptic projections of the radio sources near the line connecting the Sun and the STEREO-A spacecraft. The WAVES and SWAVES source directions revealed shifts in the latitude of the radiomore » source, indicating that the spatial location of the dominant source of the type II emission varies during the CME–CME interaction. The WAVES source directions close to 1 MHz frequencies matched the location of the leading edge of the primary CME seen in the images of the LASCO/C3 coronagraph. This correspondence of spatial locations at both wavelengths confirms that the CME–CME interaction region is the source of the type II enhancement. Comparison of radio and white-light observations also showed that at lower frequencies scattering significantly affects radio wave propagation.« less

Acoustic emission source location in complex structures using full automatic delta T mapping technique

NASA Astrophysics Data System (ADS)

Al-Jumaili, Safaa Kh.; Pearson, Matthew R.; Holford, Karen M.; Eaton, Mark J.; Pullin, Rhys

2016-05-01

An easy to use, fast to apply, cost-effective, and very accurate non-destructive testing (NDT) technique for damage localisation in complex structures is key for the uptake of structural health monitoring systems (SHM). Acoustic emission (AE) is a viable technique that can be used for SHM and one of the most attractive features is the ability to locate AE sources. The time of arrival (TOA) technique is traditionally used to locate AE sources, and relies on the assumption of constant wave speed within the material and uninterrupted propagation path between the source and the sensor. In complex structural geometries and complex materials such as composites, this assumption is no longer valid. Delta T mapping was developed in Cardiff in order to overcome these limitations; this technique uses artificial sources on an area of interest to create training maps. These are used to locate subsequent AE sources. However operator expertise is required to select the best data from the training maps and to choose the correct parameter to locate the sources, which can be a time consuming process. This paper presents a new and improved fully automatic delta T mapping technique where a clustering algorithm is used to automatically identify and select the highly correlated events at each grid point whilst the "Minimum Difference" approach is used to determine the source location. This removes the requirement for operator expertise, saving time and preventing human errors. A thorough assessment is conducted to evaluate the performance and the robustness of the new technique. In the initial test, the results showed excellent reduction in running time as well as improved accuracy of locating AE sources, as a result of the automatic selection of the training data. Furthermore, because the process is performed automatically, this is now a very simple and reliable technique due to the prevention of the potential source of error related to manual manipulation.

Correlating DMSP and NOAA Ion Precipitation Observations with Low Altitude ENA Emissions During the Declining Phase of Solar Cycle 23

NASA Astrophysics Data System (ADS)

Mackler, D. A.; Jahn, J. M.; Perez, J. D.; Pollock, C. J.

2014-12-01

Plasma sheet particles with sufficiently low mirror points will interact with thermospheric neutrals through charge exchange. The resulting ENAs are no longer magnetically bound and can therefore be detected by remote platforms outside the ionosphere/lower atmosphere. These ENAs closely associated with ion precipitation are termed Low Altitude Emissions (LAEs). They are non-isotropic in velocity space and mimic the corresponding ion pitch angle distribution. In this study we present a statistical correlation between remote observations of the LAE emission characteristics and ion precipitation maps determined in situ over the declining phase of solar cycle 23 (2000-2005). We discuss the strength and derived location (MLT, iMLAT) of LAEs as a function of geomagnetic activity levels in relation to the simultaneously measured strength, location, and spectral characteristics of in situ ion precipitation. These comparisons may allow us to use ENA images to assess where and how much energy is deposited during any type of enhanced geomagnetic activity. The precipitating ion differential directional flux maps are built up from combining NOAA-14/15/16 TED and DMSP-13/14/15 SSJ4 data. Low altitude ENA source locations are identified algorithmically using IMAGE/MENA images. ENA flux maps are derived by computing the LAE source locations assuming an ENA emission altitude (h) of 650 km, then projecting each image pixel onto a sphere with radius Re+h to determine the local time and latitude extent of the ENA source. The IGRF magnetic field model is used in combination with the Solar Magnetic coordinates of LAE pixels to compute the pitch angle of the escaping neutrals (previously ion before charge exchanging). Pitch angles larger than 90° will have a mirror point further into the atmosphere than the assumed emission altitude.

Dust emissions from undisturbed and disturbed, crusted playa surfaces: cattle trampling effects

USDA-ARS?s Scientific Manuscript database

Dry playa lake beds can be significant sources of fine dust emission. This study used a portable field wind tunnel to quantify the PM10 emissions from a bare, fine-textured playa surface located in the far northern Chihuahua Desert. The natural, undisturbed crust and its subjection to two levels of ...

Comparison of transport pathways and potential sources of PM10 in two cities around a large Chinese lake using the modified trajectory analysis

NASA Astrophysics Data System (ADS)

Kong, Xiangzhen; He, Wei; Qin, Ning; He, Qishuang; Yang, Bin; Ouyang, Huiling; Wang, Qingmei; Xu, Fuliu

2013-03-01

Trajectory cluster analysis, including the two-stage cluster method based on Euclidean metrics and the one-stage clustering method based on Mahalanobis metrics and self-organizing maps (SOM), was applied and compared to identify the transport pathways of PM10 for the cities of Chaohu and Hefei, both located near Lake Chaohu in China. The two-stage cluster method was modified to further investigate the long trajectories in the second stage in order to eliminate the observed disaggregation among them. Twelve trajectory clusters were identified for both cities. The one-stage clustering method based on Mahalanobis metrics gives the best performance regarding the variances within clusters. The results showed that local PM10 emission was one of the most important sources in both cities and that the local emission in Hefei was higher than in Chaohu. In addition, Chaohu suffered greater effects from the eastern region (Yangtze River Delta, YRD) than Hefei. On the other hand, the long-range transportation from the northwestern pathway had a higher influence on the PM10 level in Hefei. Receptor models, including potential source contribution function (PSCF) and residence time weighted concentrations (RTWC), were utilized to identify the potential source locations of PM10 for both cities. However, the combined PSCF and RTWC results for the two cities provided PM10 source locations that were more consistent with the results of transport pathways and the total anthropogenic PM10 emission inventory. This indicates that the combined method's ability to identify the source regions is superior to that of the individual PSCF or RTWC methods. Henan and Shanxi Provinces and the YRD were important PM10 source regions for the two cities, but the Henan and Shanxi area was more important for Hefei than for Chaohu, while the YRD region was less important. In addition, the PSCF, RTWC and the combined results all had higher correlation coefficients with PM10 emission from traffic than from industry, electricity generation or residential sources, suggesting the relatively higher contribution of traffic emissions to the PM10 pollution in Lake Chaohu.

Basilar membrane vibration is not involved in the reverse propagation of otoacoustic emissions

PubMed Central

He, W.; Ren, T.

2013-01-01

To understand how the inner ear-generated sound, i.e., otoacoustic emission, exits the cochlea, we created a sound source electrically in the second turn and measured basilar membrane vibrations at two longitudinal locations in the first turn in living gerbil cochleae using a laser interferometer. For a given longitudinal location, electrically evoked basilar membrane vibrations showed the same tuning and phase lag as those induced by sounds. For a given frequency, the phase measured at a basal location led that at a more apical location, indicating that either an electrical or an acoustical stimulus evoked a forward travelling wave. Under postmortem conditions, the electrically evoked emissions showed no significant change while the basilar membrane vibration nearly disappeared. The current data indicate that basilar membrane vibration was not involved in the backward propagation of otoacoustic emissions and that sounds exit the cochlea probably through alternative media, such as cochlear fluids. PMID:23695199

Spectral characteristics of VLF sferics associated with TGFs

NASA Astrophysics Data System (ADS)

Mezentsev, Andrew; Lehtinen, Nikolai; Ostgaard, Nikolai; Perez-Invernon, Javier; Cummer, Steven

2017-04-01

A detailed analysis of RHESSI TGFs is performed in association with WWLLN sources and VLF sferics recorded at Duke University. The analysis of the TGF-WWLLN matches allowed to evaluate RHESSI clock systematic offsets [1], which allows to perform a more precise timing analysis involving TGF data comparisons with the VLF sferics recorded at Duke University. In this work we analyzed the energy spectra of 35 VLF sferics, which were identified as candidates to be emitted by the TGF source, based on the simultaneity and location coincidence between the TGF and radio sources. 20 events have WWLLN detections, which provides a reliable source location of the event. For the other 15 events several selection criteria were used: source location should be consistent with the simultaneity of the TGF and VLF sferic within ±200 μs uncertainty; source location should lay within the azimuthal ±4° cone defined by the ratio of the radial and azimuthal magnetic field components of the VLF sferic; source location should lay within 800 km circle around the RHESSI foot-point; source location should lay within a cluster of a current lightning activity validated by WWLLN (or any other lightning detection network). The energy spectra of 35 VLF sferics related to TGFs were analyzed in the context of the TGF radio emission model developed in [2]. Proposed model represents a TGF at source as a sequence of Np seeding pulses of energetic particles which develop into runaway avalanches in the strong ambient field. These relativistic electrons ionize air along their propagation path which results in secondary currents of low energy electrons and light ions in the ambient electric field. These secondary currents produce radio emissions that can be detected by the ground based sensors. Proposed model allows to express the TGF source current moment energy spectrum using the T50 TGF duration measured by RHESSI. This gives the opportunity to establish and validate empirically the functional link between the satellite measurements and radio recordings of TGFs. Distances from the analyzed TGF sources to the Duke VLF receiver range from 2000 to 4000 km. This involves the consideration of the propagation effects in the Earth-ionosphere wave guide (EIWG). The EIWG transfer function was calculated for each event using the full wave propagation method. Thus, the modeled energy spectrum of the TGF source current moment can be transformed into how it would look like for the Duke VLF receiver. Comparative analysis of the energy spectra of modeled TGF radio emission and associated VLF sferics for 20 events with WWLLN confirmed location and 15 events without WWLLN detection shows that 31 of these 35 events exhibit a good fit between the modeled and observed spectra, with only 4 exceptions, that look inconsistent with the proposed model. The second cutoff frequency fB with the number of avalanches Np define the shape of the observed energy spectrum of the sferic emitted by a TGF. Multiplicity of the TGF serves as another important discriminative factor that shows the consistency between the modeled and observed spectra. The results show that the number of avalanches Np should be relatively small, of the order of 30-300, to make the modeled TGF radio emission consistent with the observed VLF sferics. These small values of Np give an argument in favor of the leader model of the TGF production, and also might refer to streamers in the streamer zone of the leader tip, as candidates, producing initial seeding pulses that develop into RREAs, generating a TGF. [1]. Mezentsev, A., Østgaard, N., Gjesteland, T., Albrechtsen, K., Lehtinen, N., Marisaldi, M., Smith, D., and Cummer, S. (2016), Radio emissions from double RHESSI TGFs, J. Geophys. Res., 121, doi:10.1002/2016JD025111 [2]. Dwyer, J. R., and S. A. Cummer (2013), Radio emissions from terrestrial gamma ray flashes, J. Geophys. Res., 118, doi:10.1002/jgra.50188.

Combined analysis of modeled and monitored SO2 concentrations at a complex smelting facility.

PubMed

Rehbein, Peter J G; Kennedy, Michael G; Cotsman, David J; Campeau, Madonna A; Greenfield, Monika M; Annett, Melissa A; Lepage, Mike F

2014-03-01

Vale Canada Limited owns and operates a large nickel smelting facility located in Sudbury, Ontario. This is a complex facility with many sources of SO2 emissions, including a mix of source types ranging from passive building roof vents to North America's tallest stack. In addition, as this facility performs batch operations, there is significant variability in the emission rates depending on the operations that are occurring. Although SO2 emission rates for many of the sources have been measured by source testing, the reliability of these emission rates has not been tested from a dispersion modeling perspective. This facility is a significant source of SO2 in the local region, making it critical that when modeling the emissions from this facility for regulatory or other purposes, that the resulting concentrations are representative of what would actually be measured or otherwise observed. To assess the accuracy of the modeling, a detailed analysis of modeled and monitored data for SO2 at the facility was performed. A mobile SO2 monitor sampled at five locations downwind of different source groups for different wind directions resulting in a total of 168 hr of valid data that could be used for the modeled to monitored results comparison. The facility was modeled in AERMOD (American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model) using site-specific meteorological data such that the modeled periods coincided with the same times as the monitored events. In addition, great effort was invested into estimating the actual SO2 emission rates that would likely be occurring during each of the monitoring events. SO2 concentrations were modeled for receptors around each monitoring location so that the modeled data could be directly compared with the monitored data. The modeled and monitored concentrations were compared and showed that there were no systematic biases in the modeled concentrations. This paper is a case study of a Combined Analysis of Modelled and Monitored Data (CAMM), which is an approach promulgated within air quality regulations in the Province of Ontario, Canada. Although combining dispersion models and monitoring data to estimate or refine estimates of source emission rates is not a new technique, this study shows how, with a high degree of rigor in the design of the monitoring and filtering of the data, it can be applied to a large industrial facility, with a variety of emission sources. The comparison of modeled and monitored SO2 concentrations in this case study also provides an illustration of the AERMOD model performance for a large industrial complex with many sources, at short time scales in comparison with monitored data. Overall, this analysis demonstrated that the AERMOD model performed well.

Pasture-scale measurement of methane emissions of grazing cattle

USDA-ARS?s Scientific Manuscript database

Quantifying methane emission of cattle grazing on southern Great Plains pastures using micrometeorology presents several challenges. Cattle are elevated, mobile point sources of methane, so that knowing their location in relation to atmospheric methane concentration measurements becomes critical. St...

SPod Progress Summary Slides

EPA Science Inventory

This presentation describes the draft “open source” design package for the SPod fenceline sensor. The SPod is a low cost, solar-powered system that combines wind field and air pollutant concentration measurements to detect emission plumes and help locate the source of emissions....

Comparison of precipitation chemistry in the Central Rocky Mountains, Colorado, USA

USGS Publications Warehouse

Heuer, K.; Tonnessen, K.A.; Ingersoll, G.P.

2000-01-01

Volume-weighted mean concentrations of nitrate (NO3-), ammonium (NH4+), and sulfate (SO42-) in precipitation were compared at high-elevation sites in Colorado from 1992 to 1997 to evaluate emission source areas to the east and west of the Rocky Mountains. Precipitation chemistry was measured by two sampling methods, the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) and snowpack surveys at maximum accumulation. Concentrations of NO3- and SO42- in winter precipitation were greater on the western slope of the Rockies, and concentrations of NO3- and NH4+ in summer precipitation were greater on the eastern slope. Summer concentrations in general were almost twice as high as winter concentrations. Seasonal weather patterns in combination with emission source areas help to explain these differences. This comparison shows that high-elevation ecosystems in Colorado are influenced by air pollution emission sources located on both sides of the Continental Divide. It also suggests that sources of nitrogen and sulfur located east of the Divide have a greater influence on precipitation chemistry in the Colorado Rockies. Copyright (C) 2000.

The global distribution of ammonia emissions from seabird colonies

NASA Astrophysics Data System (ADS)

Riddick, S. N.; Dragosits, U.; Blackall, T. D.; Daunt, F.; Wanless, S.; Sutton, M. A.

2012-08-01

Seabird colonies represent a significant source of atmospheric ammonia (NH3) in remote maritime systems, producing a source of nitrogen that may encourage plant growth, alter terrestrial plant community composition and affect the surrounding marine ecosystem. To investigate seabird NH3 emissions on a global scale, we developed a contemporary seabird database including a total seabird population of 261 million breeding pairs. We used this in conjunction with a bioenergetics model to estimate the mass of nitrogen excreted by all seabirds at each breeding colony. The results combined with the findings of mid-latitude field studies of volatilization rates estimate the global distribution of NH3 emissions from seabird colonies on an annual basis. The largest uncertainty in our emission estimate concerns the potential temperature dependence of NH3 emission. To investigate this we calculated and compared temperature independent emission estimates with a maximum feasible temperature dependent emission, based on the thermodynamic dissociation and solubility equilibria. Using the temperature independent approach, we estimate global NH3 emissions from seabird colonies at 404 Gg NH3 per year. By comparison, since most seabirds are located in relatively cold circumpolar locations, the thermodynamically dependent estimate is 136 Gg NH3 per year. Actual global emissions are expected to be within these bounds, as other factors, such as non-linear interactions with water availability and surface infiltration, moderate the theoretical temperature response. Combining sources of error from temperature (±49%), seabird population estimates (±36%), variation in diet composition (±23%) and non-breeder attendance (±13%), gives a mid estimate with an overall uncertainty range of NH3 emission from seabird colonies of 270 [97-442] Gg NH3 per year. These emissions are environmentally relevant as they primarily occur as "hot-spots" in otherwise pristine environments with low anthropogenic emissions.

Relating to ion detection

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore

2001-01-01

The apparatus and method provide a technique for improving detection of alpha and/or beta emitting sources on items or in locations using indirect means. The emission forms generate ions in a medium surrounding the item or location and the medium is then moved to a detecting location where the ions are discharged to give a measure of the emission levels. To increase the level of ions generated and render the system particularly applicable for narrow pipes and other forms of conduits, the medium pressure is increased above atmospheric pressure. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Development of a Flight Instrument for in situ Measurements of Ethane and Methane

NASA Astrophysics Data System (ADS)

Wilkerson, J. P.; Sayres, D. S.; Anderson, J. G.

2015-12-01

Methane emissions data for natural gas and oil fields have high uncertainty. Better quantifying these emissions is crucial to establish an accurate methane budget for the United States. One obstacle is that these emissions often occur in areas near livestock facilities where biogenic methane abounds. Measuring ethane, which has no biogenic source, along with methane can tease these sources apart. However, ethane is typically measured by taking whole-air samples. This tactic has lower spatial resolution than making in situ measurements and requires the measurer to anticipate the location of emission plumes. This leaves unexpected plumes uncharacterized. Using Re-injection Mirror Integrated Cavity Output Spectroscopy (RIM-ICOS), we can measure both methane and ethane in flight, allowing us to establish more accurate fugitive emissions data that can more readily distinguish between different sources of this greenhouse gas.

Pasture-scale methane emissions of grazing cattle

USDA-ARS?s Scientific Manuscript database

Grazing cattle are mobile point sources of methane and present challenges to quantify emissions using noninterfering micrometeorological methods. Stocking density is low and cattle can bunch up or disperse over a wide area, so knowing cattle locations is critical. The methane concentration downwind ...

Plasma and radio waves from Neptune: Source mechamisms and propagation

NASA Technical Reports Server (NTRS)

Menietti, J. Douglas

1994-01-01

The purpose of this project was to conduct a comprehensive investigation of the radio wave emission observed by the planetary radio astronomy (PRA) instrument on board Voyager 2 as it flew by Neptune. The study has included data analysis, theoretical and numerical calculations, and ray tracing to determine the possible source mechanisms and locations of the radiation, including the narrowband bursty and smooth components of the Neptune radio emission.

Quantifying methane emissions from coal and natural gas sources along the northwestern Appalachian

NASA Astrophysics Data System (ADS)

Barkley, Z.; Lauvaux, T.; Davis, K. J.; Fried, A.

2017-12-01

According to the EPA's 2012 gridded inventory (Maasakkers et al., 2016), more than 10% of all CH4 emissions in the U.S. are located along the western edge of the Appalachian with the majority of these emissions coming from natural gas infrastructure and coal mines. However, top-down studies of unconventional wells in southwestern Pennsylvania have found emission rates to be much higher than EPA estimates (Caulton et al., 2014, Ren et al., 2017). Furthermore, although 9 of the 10 largest sources of CH4 in the EPA Greenhouse Gas Reporting Program are coal mines located in this region, no top down studies have been performed to assess the accuracy of these enormous point sources. This study uses aircraft data from the ACT-America flight campaign in conjunction with techniques previously used to solve for CH4 emissions from the northeastern Marcellus (Barkley et al., 2017) to quantify the total CH4 flux from the western Pennsylvania/West Virginia region and constrain emissions from natural gas and coal with an upper limit for each source. We use the WRF-Chem mesoscale model at 3 km resolution to simulate CH4 enhancements from a customized emissions inventory and compare the modelled enhancements to observations from 7 flights that were downwind of coal and gas sources. Coal and natural gas emissions are adjusted in the model to minimize a cost function that accounts for the difference between the modelled and observed CH4 values, and a range of likely combinations for natural gas and coal emission rates are obtained for each flight. We then overlap this range of likely emission rates across all flights to further limit the range of possible emission rates. Influence functions created using a lagrangian particle dispersion model for segments of each flight provide information on what area emissions are being optimized for. Preliminary results find that CH4 emissions from gas and coal along the northwestern Appalachian are lower than EPA estimates by 20-50%. In particular, upper limits on CH4 emissions from unconventional natural gas are less than 1% of total production, significantly lower than previous top-down estimates in the region. Future work will use ethane data to better distinguish between coal and natural gas emissions, and expand these analyses to other study regions explored in the ACT-America aircraft campaign.

Mercury emissions from coal combustion in Silesia, analysis using geostatistics

NASA Astrophysics Data System (ADS)

Zasina, Damian; Zawadzki, Jaroslaw

2015-04-01

Data provided by the UNEP's report on mercury [1] shows that solid fuel combustion in significant source of mercury emission to air. Silesia, located in southwestern Poland, is notably affected by mercury emission due to being one of the most industrialized Polish regions: the place of coal mining, production of metals, stone mining, mineral quarrying and chemical industry. Moreover, Silesia is the region with high population density. People are exposed to severe risk of mercury emitted from both: industrial and domestic sources (i.e. small household furnaces). Small sources have significant contribution to total emission of mercury. Official and statistical analysis, including prepared for international purposes [2] did not provide data about spatial distribution of the mercury emitted to air, however number of analysis on Polish public power and energy sector had been prepared so far [3; 4]. The distribution of locations exposed for mercury emission from small domestic sources is interesting matter merging information from various sources: statistical, economical and environmental. This paper presents geostatistical approach to distibution of mercury emission from coal combustion. Analysed data organized in 2 independent levels: individual, bottom-up approach derived from national emission reporting system [5; 6] and top down - regional data calculated basing on official statistics [7]. Analysis, that will be presented, will include comparison of spatial distributions of mercury emission using data derived from sources mentioned above. Investigation will include three voivodeships of Poland: Lower Silesian, Opole (voivodeship) and Silesian using selected geostatistical methodologies including ordinary kriging [8]. References [1] UNEP. Global Mercury Assessment 2013: Sources, Emissions, Releases and Environmental Transport. UNEP Chemicals Branch, Geneva, Switzerland, 2013. [2] NCEM. Poland's Informative Inventory Report 2014. NCEM at the IEP-NRI, 2014. http://www.ceip.at/. [3] Zyśk J., Wyrwa A. and Pluta M. Emissions of mercury from the power sector in Poland. Atmospheric Environment, 45:605-610, 2011. http://dx.doi.org/10.1016/j.atmosenv.2010.10.041/. [4] Głodek A., Pacyna J. Mercury emission from coal-fired power plants in Poland. Atmospheric Environment, 43:5668-5673, 2009. http://dx.doi.org/10.1016/j.atmosenv.2009.07.041. [5] NCEM. National emission database, 2014. NCEM Management at the IEP-NRI. [6] Zasina D. and Zawadzki J. Disaggregation problems using data derived from polish air pollutant emission management system, Systems Supporting Production Engineering. Review of Problems and Solutions, ISBN 978-83-937845-9-2, pp. 128-137, 2014. [7] EUROSTAT. EUROSTAT Energy Database, 2014. [8] Wackernagel H. Basics in Geostatistics 3 Geostatistical Monte-Carlo methods: Conditional simulation, 2013.

An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array.

PubMed

Yan, Gang; Zhou, Li

2018-02-21

This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method.

An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array

PubMed Central

Zhou, Li

2018-01-01

This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method. PMID:29466310

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

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-09

... for Existing Sources: Commercial and Industrial Solid Waste Incineration Units; Identification of Non-Hazardous Secondary Materials That Are Solid Waste AGENCY: Environmental Protection Agency. ACTION: Notice... Institutional Boilers located at area sources; and Commercial and Industrial Solid Waste Incineration Units. On...

Source profiles for nonmethane organic compounds in the atmosphere of Cairo, Egypt.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doskey, P. V.; Fukui, Y.; Sultan, M.

1999-07-01

Profiles of the sources of nonmethane organic compounds (NMOCs) were developed for emissions from vehicles, petroleum fuels (gasoline, liquefied petroleum gas (LPG), and natural gas), a petroleum refinery, a smelter, and a cast iron factory in Cairo, Egypt. More than 100 hydrocarbons and oxygenated hydrocarbons were tentatively identified and quantified. Gasoline-vapor and whole-gasoline profiles could be distinguished from the other profiles by high concentrations of the C{sub 5} and C{sub 6} saturated hydrocarbons. The vehicle emission profile was similar to the whole-gasoline profile, with the exception of the unsaturated and aromatic hydrocarbons, which were present at higher concentrations in themore » vehicle emission profile. High levels of the C{sub 2}-C{sub 4} saturated hydrocarbons, particularly n-butane, were characteristic features of the petroleum refinery emissions. The smelter and cast iron factory emissions were similar to the refinery emissions; however, the levels of benzene and toluene were greater in the former two sources. The LPG and natural gas emissions contained high concentrations of n-butane and ethane, respectively. The NMOC source profiles for Cairo were distinctly different from profiles for U.S. sources, indicating that NMOC source profiles are sensitive to the particular composition of petroleum fuels that are used in a location.« less

An integrated WRF/HYSPLIT modeling approach for the assessment of PM(2.5) source regions over the Mississippi Gulf Coast region.

PubMed

Yerramilli, Anjaneyulu; Dodla, Venkata Bhaskar Rao; Challa, Venkata Srinivas; Myles, Latoya; Pendergrass, William R; Vogel, Christoph A; Dasari, Hari Prasad; Tuluri, Francis; Baham, Julius M; Hughes, Robert L; Patrick, Chuck; Young, John H; Swanier, Shelton J; Hardy, Mark G

2012-12-01

Fine particulate matter (PM(2.5)) is majorly formed by precursor gases, such as sulfur dioxide (SO(2)) and nitrogen oxides (NO(x)), which are emitted largely from intense industrial operations and transportation activities. PM(2.5) has been shown to affect respiratory health in humans. Evaluation of source regions and assessment of emission source contributions in the Gulf Coast region of the USA will be useful for the development of PM(2.5) regulatory and mitigation strategies. In the present study, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model driven by the Weather Research & Forecasting (WRF) model is used to identify the emission source locations and transportation trends. Meteorological observations as well as PM(2.5) sulfate and nitric acid concentrations were collected at two sites during the Mississippi Coastal Atmospheric Dispersion Study, a summer 2009 field experiment along the Mississippi Gulf Coast. Meteorological fields during the campaign were simulated using WRF with three nested domains of 36, 12, and 4 km horizontal resolutions and 43 vertical levels and validated with North American Mesoscale Analysis. The HYSPLIT model was integrated with meteorological fields derived from the WRF model to identify the source locations using backward trajectory analysis. The backward trajectories for a 24-h period were plotted at 1-h intervals starting from two observation locations to identify probable sources. The back trajectories distinctly indicated the sources to be in the direction between south and west, thus to have origin from local Mississippi, neighboring Louisiana state, and Gulf of Mexico. Out of the eight power plants located within the radius of 300 km of the two monitoring sites examined as sources, only Watson, Cajun, and Morrow power plants fall in the path of the derived back trajectories. Forward dispersions patterns computed using HYSPLIT were plotted from each of these source locations using the hourly mean emission concentrations as computed from past annual emission strength data to assess extent of their contribution. An assessment of the relative contributions from the eight sources reveal that only Cajun and Morrow power plants contribute to the observations at the Wiggins Airport to a certain extent while none of the eight power plants contribute to the observations at Harrison Central High School. As these observations represent a moderate event with daily average values of 5-8 μg m(-3) for sulfate and 1-3 μg m(-3) for HNO(3) with differences between the two spatially varied sites, the local sources may also be significant contributors for the observed values of PM(2.5).

Waveform Based Acoustic Emission Detection and Location of Matrix Cracking in Composites

NASA Technical Reports Server (NTRS)

Prosser, W. H.

1995-01-01

The operation of damage mechanisms in a material or structure under load produces transient acoustic waves. These acoustic waves are known as acoustic emission (AE). In composites they can be caused by a variety of sources including matrix cracking, fiber breakage, and delamination. AE signals can be detected and analyzed to determine the location of the acoustic source by triangulation. Attempts are also made to analyze the signals to determine the type and severity of the damage mechanism. AE monitoring has been widely used for both laboratory studies of materials, and for testing the integrity of structures in the field. In this work, an advanced, waveform based AE system was used in a study of transverse matrix cracking in cross-ply graphite/epoxy laminates. This AE system featured broad band, high fidelity sensors, and high capture rate digital acquisition and storage of acoustic signals. In addition, analysis techniques based on plate wave propagation models were employed. These features provided superior source location and noise rejection capabilities.

Mapping Terpenes over the Teakettle Experimental Forest

NASA Astrophysics Data System (ADS)

Tycner, J.; Ustin, S.; Grigsby, S.

2015-12-01

Terpenes are a category of biogenic volatile organic compounds (BVOC) produced by many plants, most notably coniferous plants. Commonly, these terpenes are aromatic compounds. The intensity of terpene emission varies depending greatly on light and temperature. Through remote sensing data as well as ASD spectroradiometry data this study focuses on locating sources of terpene emissions in the Teakettle Experimental Forest. These emissions are of particular concern because of their influence on the chemical concentration of the lower troposphere, as well as being an indicator of tree health. A novel approach has been designed through this study in order to locate and further understand these terpene emissions. Terpenes such as camphene have been reported to have subtle spectral features located at around 1.7 μm. For the first time, a map of terpene sources has been constructed by accentuating this particular feature. A continuum interpolated band ratio (CIBR) was used in order to compute a relative abundance of terpenes from the AVIRIS data. The CIBR equation showed promise, as terpenes were most strongly concentrated in areas of coniferous vegetation (a primary source of terpenes) and were less prominent over bodies of water or industrialized areas. The greatest concentrations were focused over treetops and other woody vegetation. Although it is known that terpenes have weak absorption features in the SWIR, there is little information available regarding the mapping of terpene emissions. This project addresses a novel approach to observing biochemical components in the lower troposphere and could potentially give more information to explain the health of forest ecosystems.

A probabilistic framework for single-sensor acoustic emission source localization in thin metallic plates

NASA Astrophysics Data System (ADS)

Ebrahimkhanlou, Arvin; Salamone, Salvatore

2017-09-01

Tracking edge-reflected acoustic emission (AE) waves can allow the localization of their sources. Specifically, in bounded isotropic plate structures, only one sensor may be used to perform these source localizations. The primary goal of this paper is to develop a three-step probabilistic framework to quantify the uncertainties associated with such single-sensor localizations. According to this framework, a probabilistic approach is first used to estimate the direct distances between AE sources and the sensor. Then, an analytical model is used to reconstruct the envelope of edge-reflected AE signals based on the source-to-sensor distance estimations and their first arrivals. Finally, the correlation between the probabilistically reconstructed envelopes and recorded AE signals are used to estimate confidence contours for the location of AE sources. To validate the proposed framework, Hsu-Nielsen pencil lead break (PLB) tests were performed on the surface as well as the edges of an aluminum plate. The localization results show that the estimated confidence contours surround the actual source locations. In addition, the performance of the framework was tested in a noisy environment simulated by two dummy transducers and an arbitrary wave generator. The results show that in low-noise environments, the shape and size of the confidence contours depend on the sources and their locations. However, at highly noisy environments, the size of the confidence contours monotonically increases with the noise floor. Such probabilistic results suggest that the proposed probabilistic framework could thus provide more comprehensive information regarding the location of AE sources.

Tracking the Spatial Fate of PCDD/F Emissions from a Cement Plant by Using Lichens as Environmental Biomonitors.

PubMed

Augusto, Sofia; Pinho, Pedro; Santos, Artur; Botelho, Maria João; Palma-Oliveira, José; Branquinho, Cristina

2016-03-01

In an area with multiple sources of air pollution, it is difficult to evaluate the spatial impact of a minor source. Here, we describe the use of lichens to track minor sources of air pollution. The method was tested by transplanting lichens from a background area to the vicinity of a cement manufacturing plant that uses alternative fuel and is located in a Natural Park in an area surrounded by other important sources of pollution. After 7 months of exposure, the lichens were collected and analyzed for 17 PCDD/F congeners. The PCDD/F profiles of the exposed lichens were dominated by TCDF (50%) and OCDD (38%), which matched the profile of the emissions from the cement plant. The similarity in the profiles was greatest for lichens located northeast of the plant (i.e., in the direction of the prevailing winds during the study period), allowing us to evaluate the spatial impact of this source. The best match was found for sites located on the tops of mountains whose slopes faced the cement plant. Some of the sites with highest influence of the cement plant were the ones with the highest concentrations, whereas others were not. Thus, our newly developed lichen-based method provides a tool for tracking the spatial fate of industrially emitted PCDD/Fs regardless of their concentrations. The results showed that the method can be used to validate deposition models for PCDD/F industrial emissions in sites with several sources and characterized by complex orography.

Characterizing CO and NOy Sources and Relative Ambient Ratios in the Baltimore Area Using Ambient Measurements and Source Attribution Modeling

NASA Astrophysics Data System (ADS)

Simon, Heather; Valin, Luke C.; Baker, Kirk R.; Henderson, Barron H.; Crawford, James H.; Pusede, Sally E.; Kelly, James T.; Foley, Kristen M.; Chris Owen, R.; Cohen, Ronald C.; Timin, Brian; Weinheimer, Andrew J.; Possiel, Norm; Misenis, Chris; Diskin, Glenn S.; Fried, Alan

2018-03-01

Modeled source attribution information from the Community Multiscale Air Quality model was coupled with ambient data from the 2011 Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality Baltimore field study. We assess source contributions and evaluate the utility of using aircraft measured CO and NOy relationships to constrain emission inventories. We derive ambient and modeled ΔCO:ΔNOy ratios that have previously been interpreted to represent CO:NOy ratios in emissions from local sources. Modeled and measured ΔCO:ΔNOy are similar; however, measured ΔCO:ΔNOy has much more daily variability than modeled values. Sector-based tagging shows that regional transport, on-road gasoline vehicles, and nonroad equipment are the major contributors to modeled CO mixing ratios in the Baltimore area. In addition to those sources, on-road diesel vehicles, soil emissions, and power plants also contribute substantially to modeled NOy in the area. The sector mix is important because emitted CO:NOx ratios vary by several orders of magnitude among the emission sources. The model-predicted gasoline/diesel split remains constant across all measurement locations in this study. Comparison of ΔCO:ΔNOy to emitted CO:NOy is challenged by ambient and modeled evidence that free tropospheric entrainment, and atmospheric processing elevates ambient ΔCO:ΔNOy above emitted ratios. Specifically, modeled ΔCO:ΔNOy from tagged mobile source emissions is enhanced 5-50% above the emitted ratios at times and locations of aircraft measurements. We also find a correlation between ambient formaldehyde concentrations and measured ΔCO:ΔNOy suggesting that secondary CO formation plays a role in these elevated ratios. This analysis suggests that ambient urban daytime ΔCO:ΔNOy values are not reflective of emitted ratios from individual sources.

A Bayesian Multivariate Receptor Model for Estimating Source Contributions to Particulate Matter Pollution using National Databases.

PubMed

Hackstadt, Amber J; Peng, Roger D

2014-11-01

Time series studies have suggested that air pollution can negatively impact health. These studies have typically focused on the total mass of fine particulate matter air pollution or the individual chemical constituents that contribute to it, and not source-specific contributions to air pollution. Source-specific contribution estimates are useful from a regulatory standpoint by allowing regulators to focus limited resources on reducing emissions from sources that are major contributors to air pollution and are also desired when estimating source-specific health effects. However, researchers often lack direct observations of the emissions at the source level. We propose a Bayesian multivariate receptor model to infer information about source contributions from ambient air pollution measurements. The proposed model incorporates information from national databases containing data on both the composition of source emissions and the amount of emissions from known sources of air pollution. The proposed model is used to perform source apportionment analyses for two distinct locations in the United States (Boston, Massachusetts and Phoenix, Arizona). Our results mirror previous source apportionment analyses that did not utilize the information from national databases and provide additional information about uncertainty that is relevant to the estimation of health effects.

CS Emission Near MIR-bubbles

NASA Astrophysics Data System (ADS)

Watson, C.; Devine, Kathryn; Quintanar, N.; Candelaria, T.

2016-02-01

We survey 44 young stellar objects located near the edges of mid-IR-identified bubbles in CS (1-0) using the Green Bank Telescope. We detect emission in 18 sources, indicating young protostars that are good candidates for being triggered by the expansion of the bubble. We calculate CS column densities and abundances. Three sources show evidence of infall through non-Gaussian line-shapes. Two of these sources are associated with dark clouds and are promising candidates for further exploration of potential triggered star formation. We obtained on-the-fly maps in CS (1-0) of three sources, showing evidence of significant interactions between the sources and the surrounding environment.

Uncertainty in gridded CO 2 emissions estimates

DOE PAGES

Hogue, Susannah; Marland, Eric; Andres, Robert J.; ...

2016-05-19

We are interested in the spatial distribution of fossil-fuel-related emissions of CO 2 for both geochemical and geopolitical reasons, but it is important to understand the uncertainty that exists in spatially explicit emissions estimates. Working from one of the widely used gridded data sets of CO 2 emissions, we examine the elements of uncertainty, focusing on gridded data for the United States at the scale of 1° latitude by 1° longitude. Uncertainty is introduced in the magnitude of total United States emissions, the magnitude and location of large point sources, the magnitude and distribution of non-point sources, and from themore » use of proxy data to characterize emissions. For the United States, we develop estimates of the contribution of each component of uncertainty. At 1° resolution, in most grid cells, the largest contribution to uncertainty comes from how well the distribution of the proxy (in this case population density) represents the distribution of emissions. In other grid cells, the magnitude and location of large point sources make the major contribution to uncertainty. Uncertainty in population density can be important where a large gradient in population density occurs near a grid cell boundary. Uncertainty is strongly scale-dependent with uncertainty increasing as grid size decreases. In conclusion, uncertainty for our data set with 1° grid cells for the United States is typically on the order of ±150%, but this is perhaps not excessive in a data set where emissions per grid cell vary over 8 orders of magnitude.« less

The Deployment of Sensor Network Intelligent Emission Locator (SENTINEL) for Fenceline Emission Measurements

EPA Science Inventory

Abstract: As part of the Petroleum Refinery Risk and Technology Review, New Source Performance Standards rule, US EPA is proposing use of two-week passive sorbant tube fenceline monitoring for benzene. With recent technological advances, low-cost time-resolved sensors may become...

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This... operate a stationary combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication...

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This... operate a stationary combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication...

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This... operate a stationary combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all equipment, including but not limited to the turbine, the fuel, air, lubrication...

40 CFR 63.1404 - Storage vessel provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Storage vessel provisions. 63.1404... Standards for Hazardous Air Pollutant Emissions: Manufacture of Amino/Phenolic Resins § 63.1404 Storage vessel provisions. (a) Emission standards. For each storage vessel located at a new affected source that...

40 CFR 63.1404 - Storage vessel provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Storage vessel provisions. 63.1404... Standards for Hazardous Air Pollutant Emissions: Manufacture of Amino/Phenolic Resins § 63.1404 Storage vessel provisions. (a) Emission standards. For each storage vessel located at a new affected source that...

Long-term trends of ambient particulate matter emission source contributions and the accountability of control strategies in Hong Kong over 1998-2008

NASA Astrophysics Data System (ADS)

Yuan, Zibing; Yadav, Varun; Turner, Jay R.; Louie, Peter K. K.; Lau, Alexis Kai Hon

2013-09-01

Despite extensive emission control measures targeting motor vehicles and to a lesser extent other sources, annual-average PM10 mass concentrations in Hong Kong have remained relatively constant for the past several years and for some air quality metrics, such as the frequency of poor visibility days, conditions have degraded. The underlying drivers for these long-term trends were examined by performing source apportionment on eleven years (1998-2008) of data for seven monitoring sites in the Hong Kong PM10 chemical speciation network. Nine factors were resolved using Positive Matrix Factorization. These factors were assigned to emission source categories that were classified as local (operationally defined as within the Hong Kong Special Administrative Region) or non-local based on temporal and spatial patterns in the source contribution estimates. This data-driven analysis provides strong evidence that local controls on motor vehicle emissions have been effective in reducing motor vehicle-related ambient PM10 burdens with annual-average contributions at neighborhood- and larger-scale monitoring stations decreasing by ˜6 μg m-3 over the eleven year period. However, this improvement has been offset by an increase in annual-average contributions from non-local contributions, especially secondary sulfate and nitrate, of ˜8 μg m-3 over the same time period. As a result, non-local source contributions to urban-scale PM10 have increased from 58% in 1998 to 70% in 2008. Most of the motor vehicle-related decrease and non-local source driven increase occurred over the period 1998-2004 with more modest changes thereafter. Non-local contributions increased most dramatically for secondary sulfate and secondary nitrate factors and thus combustion-related control strategies, including but not limited to power plants, are needed for sources located in the Pearl River Delta and more distant regions to improve air quality conditions in Hong Kong. PMF-resolved source contribution estimates were also used to examine differential contributions of emission source categories during high PM episodes compared to study-average behavior. While contributions from all source categories increased to some extent on high PM days, the increases were disproportionately high for the non-local sources. Thus, controls on emission sources located outside the Hong Kong Special Administrative Region will be needed to effectively decrease the frequency and severity of high PM episodes.

A portable neutron spectroscope (NSPECT) for detection, imaging and identification of nuclear material

NASA Astrophysics Data System (ADS)

Ryan, James M.; Bancroft, Christopher; Bloser, Peter; Bravar, Ulisse; Fourguette, Dominique; Frost, Colin; Larocque, Liane; McConnell, Mark L.; Legere, Jason; Pavlich, Jane; Ritter, Greg; Wassick, Greg; Wood, Joshua; Woolf, Richard

2010-08-01

We have developed, fabricated and tested a prototype imaging neutron spectrometer designed for real-time neutron source location and identification. Real-time detection and identification is important for locating materials. These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other forms of radiation (e.g. gamma rays), penetrating neutron emission is very uncommon. The instrument detects these neutrons, constructs images of the emission pattern, and reports the neutron spectrum. The device will be useful for security and proliferation deterrence, as well as for nuclear waste characterization and monitoring. The instrument is optimized for imaging and spectroscopy in the 1-20 MeV range. The detection principle is based upon multiple elastic neutron-proton scatters in organic scintillator. Two detector panel layers are utilized. By measuring the recoil proton and scattered neutron locations and energies, the direction and energy spectrum of the incident neutrons can be determined and discrete and extended sources identified. Event reconstruction yields an image of the source and its location. The hardware is low power, low mass, and rugged. Its modular design allows the user to combine multiple units for increased sensitivity. We will report the results of laboratory testing of the instrument, including exposure to a calibrated Cf-252 source. Instrument parameters include energy and angular resolution, gamma rejection, minimum source identification distances and times, and projected effective area for a fully populated instrument.

40 CFR 63.6603 - What emission limitations and operating limitations must I meet if I own or operate an existing...

Code of Federal Regulations, 2011 CFR

2011-07-01

... operating limitations must I meet if I own or operate an existing stationary RICE located at an area source... operating limitations must I meet if I own or operate an existing stationary RICE located at an area source... procedures in § 63.6620 and Table 4 to this subpart. (a) If you own or operate an existing stationary RICE...

Volcanic gas emissions and their effect on ambient air character

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutton, A.J.; Elias, T.

1994-01-01

This bibliography was assembled to service an agreement between Department of Energy and the USGS to provide a body of references and useful annotations for understanding background gas emissions from Kilauea volcano. The current East Rift Zone (ERZ) eruption of Kilauea releases as much as 500,000 metric tonnes of SO{sub 2} annually, along with lesser amounts of other chemically and radiatively active species including H{sub 2}S, HCl, and HF. Primary degassing locations on Kilauea are located in the summit caldera and along the middle ERZ. The effects of these emissions on ambient air character are a complex function of chemicalmore » reactivity, source geometry and effusivity, and local meteorology. Because of this complexity, we organized the bibliography into three main sections: (1) characterizing gases as they leave the edifice; (2) characterizing gases and chemical reaction products away from degassing sources; and (3) Hawaii Island meteorology.« less

40 CFR 62.6110 - Identification of sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Sulfuric Acid Mist from Existing Sulfuric Acid Plants § 62.6110 Identification of sources. The plan applies to existing plants at the following locations: Sulfur burning plant and oleum plant of Mississippi Chemical Corporation in Pascagoula. Fluoride Emissions From Phosphate Fertilizer Plants ...

40 CFR 62.6110 - Identification of sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Sulfuric Acid Mist from Existing Sulfuric Acid Plants § 62.6110 Identification of sources. The plan applies to existing plants at the following locations: Sulfur burning plant and oleum plant of Mississippi Chemical Corporation in Pascagoula. Fluoride Emissions From Phosphate Fertilizer Plants ...

40 CFR 62.6110 - Identification of sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Sulfuric Acid Mist from Existing Sulfuric Acid Plants § 62.6110 Identification of sources. The plan applies to existing plants at the following locations: Sulfur burning plant and oleum plant of Mississippi Chemical Corporation in Pascagoula. Fluoride Emissions From Phosphate Fertilizer Plants ...

40 CFR 62.6110 - Identification of sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Sulfuric Acid Mist from Existing Sulfuric Acid Plants § 62.6110 Identification of sources. The plan applies to existing plants at the following locations: Sulfur burning plant and oleum plant of Mississippi Chemical Corporation in Pascagoula. Fluoride Emissions From Phosphate Fertilizer Plants ...

40 CFR 62.6110 - Identification of sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Sulfuric Acid Mist from Existing Sulfuric Acid Plants § 62.6110 Identification of sources. The plan applies to existing plants at the following locations: Sulfur burning plant and oleum plant of Mississippi Chemical Corporation in Pascagoula. Fluoride Emissions From Phosphate Fertilizer Plants ...

Characterization of Industrial Emission Sources and Photochemistry in Houston, Texas

NASA Astrophysics Data System (ADS)

Washenfelder, R. A.; Atlas, E. L.; Degouw, J.; Flocke, F. M.; Fried, A.; Frost, G. J.; Holloway, J.; Richter, D.; Ryerson, T. B.; Schauffler, S.; Trainer, M.; Walega, J.; Warneke, C.; Weibring, P.; Zheng, W.

2009-12-01

The Houston-Galveston urban area contains a number of large industrial petrochemical emission sources that produce volatile organic compounds and nitrogen oxides. These co-located emissions result in rapid and efficient ozone production downwind. Unlike a single large power plant, the industrial complexes consist of numerous sources that can be difficult to quantify in emission inventories. During September - October 2006, the NOAA WP-3 aircraft conducted research flights as part of the second Texas Air Quality Study (TexAQS II). We examine measurements of NOx, SO2, and speciated hydrocarbons from the Houston Ship Channel, which contains a dense concentration of industrial petrochemical sources, and isolated petrochemical facilities. These measurements are used to derive source emission estimates, which are then compared to available emission inventories. We find that high hydrocarbon emissions are typical for the Houston Ship Channel and isolated petrochemical facilities. Ethene and propene are found to be major contributors to ozone formation. Ratios of C2H4 / NOx and C3H6 / NOx exceed emission inventory values by factors of 10 - 50. These findings are consistent with the first TexAQS study in 2000. We examine trends in C2H4 / NOx and C3H6 / NOx ratios between 2000 and 2006, and determine that day-to-day variability and within-plume variability exceeds any long-term reduction in ethene and propene emissions for the isolated petrochemical sources. We additionally examine downwind photochemical products formed by these alkenes.

Coupling a Neural Network with Atmospheric Flow Simulations to Locate and Quantify CH4 Emissions at Well Pads

NASA Astrophysics Data System (ADS)

Travis, B. J.; Sauer, J.; Dubey, M. K.

2017-12-01

Methane (CH4) leaks from oil and gas production fields are a potentially significant source of atmospheric methane. US DOE's ARPA-E office is supporting research to locate methane emissions at 10 m size well pads to within 1 m. A team led by Aeris Technologies, and that includes LANL, Planetary Science Institute and Rice University has developed an autonomous leak detection system (LDS) employing a compact laser absorption methane sensor, a sonic anemometer and multiport sampling. The LDS system analyzes monitoring data using a convolutional neural network (cNN) to locate and quantify CH4 emissions. The cNN was trained using three sources: (1) ultra-high-resolution simulations of methane transport provided by LANL's coupled atmospheric transport model HIGRAD, for numerous controlled methane release scenarios and methane sampling configurations under variable atmospheric conditions, (2) Field tests at the METEC site in Ft. Collins, CO., and (3) Field data from other sites where point-source surface methane releases were monitored downwind. A cNN learning algorithm is well suited to problems in which the training and observed data are noisy, or correspond to complex sensor data as is typical of meteorological and sensor data over a well pad. Recent studies with our cNN emphasize the importance of tracking wind speeds and directions at fine resolution ( 1 second), and accounting for variations in background CH4 levels. A few cases illustrate the importance of sufficiently long monitoring; short monitoring may not provide enough information to determine accurately a leak location or strength, mainly because of short-term unfavorable wind directions and choice of sampling configuration. Length of multiport duty cycle sampling and sample line flush time as well as number and placement of monitoring sensors can significantly impact ability to locate and quantify leaks. Source location error at less than 10% requires about 30 or more training cases.

Impact of Urban, Agricultural and Industrial Emissions on the Atmospheric Reactive Nitrogen in the Columbia River Gorge Scenic Area

NASA Astrophysics Data System (ADS)

Mainord, J.; George, L. A.; Orlando, P.

2015-12-01

Secondary inorganic aerosol (SIA) formation is not fully characterized due to inadequate knowledge of pre-cursor emissions (ammonia, NH3, and nitrogen oxides, NOx) and from incomplete understanding of reactions in model predictions involving the precursors and the chemical products such as nitric acid (HNO3). The Columbia River Gorge (CRG), located between Oregon and Washington states, has unique sources of reactive nitrogen located at both ends and experiences bimodal winds: winter easterlies and summer westerlies. Because of the unique winds, this project will utilize the CRG as an environmental flow tube as we monitor for atmospheric reactive nitrogen species at two locations within the CRG: one located on the western side and one on the east. Measurements will include total oxidized nitrogen, NOx, NH3 and HNO3 using annular denuders, and a novel method using ion exchange resins for particulate ammonium, nitrate, and sulfates. In addition, an ozone gas analyzer and meteorological conditions of temperature, relative humidity, wind speed and direction will be measured. Our December 2012- June 2014 NOx measurements located near the eastern end of the CRG show significantly different (p<<0.05) levels of NO2 with easterly (8.1 ppb) versus westerly (5.7 ppb) wind conditions. This suggests an eastern NOx source - potentially the 550 megawatt Boardman Coal Power Plant 100 km to the east. These measurements in the near-source environment will provide insight into uncertainties in HNO3 formation, regional ammonia levels, and the best strategy for managers to reduce NOx or NH3 emissions to minimize SIA formation.

Fugitive coke oven gas emission profile by continuous line averaged open-path Fourier transform infrared monitoring.

PubMed

Lin, Chitsan; Liou, Naiwei; Chang, Pao-Erh; Yang, Jen-Chin; Sun, Endy

2007-04-01

Although most coke oven research is focused on the emission of polycyclic aromatic hydrocarbons, well-known carcinogens, little has been done on the emission of volatile organic compounds, some of which are also thought to be hazardous to workers and the environment. To profile coke oven gas (COG) emissions, we set up an open-path Fourier transform infrared (OP-FTIR) system on top of a battery of coke ovens at a steel mill located in Southern Taiwan and monitored average emissions in a coke processing area for 16.5 hr. Nine COGs were identified, including ammonia, CO, methane, ethane, ethylene, acetylene, propylene, cyclohexane, and O-xylene. Time series plots indicated that the type of pollutants differed over time, suggesting that different emission sources (e.g., coke pushing, quench tower, etc.) were involved at different times over the study period. This observation was confirmed by the low cross-correlation coefficients of the COGs. It was also found that, with the help of meteorological analysis, the data collected by the OP-FTIR system could be analyzed effectively to characterize differences in the location of sources. Although the traditional single-point samplings of emissions involves sampling various sources in a coke processing area at several different times and is a credible profiling of emissions, our findings strongly suggest that they are not nearly as efficient or as cost-effective as the continuous line average method used in this study. This method would make it easier and cheaper for engineers and health risk assessors to identify and to control fugitive volatile organic compound emissions and to improve environmental health.

Time-resolved tomography using acoustic emissions in the laboratory, and application to sandstone compaction

NASA Astrophysics Data System (ADS)

Brantut, Nicolas

2018-02-01

Acoustic emission and active ultrasonic wave velocity monitoring are often performed during laboratory rock deformation experiments, but are typically processed separately to yield homogenised wave velocity measurements and approximate source locations. Here I present a numerical method and its implementation in a free software to perform a joint inversion of acoustic emission locations together with the three-dimensional, anisotropic P-wave structure of laboratory samples. The data used are the P-wave first arrivals obtained from acoustic emissions and active ultrasonic measurements. The model parameters are the source locations and the P-wave velocity and anisotropy parameter (assuming transverse isotropy) at discrete points in the material. The forward problem is solved using the fast marching method, and the inverse problem is solved by the quasi-Newton method. The algorithms are implemented within an integrated free software package called FaATSO (Fast Marching Acoustic Emission Tomography using Standard Optimisation). The code is employed to study the formation of compaction bands in a porous sandstone. During deformation, a front of acoustic emissions progresses from one end of the sample, associated with the formation of a sequence of horizontal compaction bands. Behind the active front, only sparse acoustic emissions are observed, but the tomography reveals that the P-wave velocity has dropped by up to 15%, with an increase in anisotropy of up to 20%. Compaction bands in sandstones are therefore shown to produce sharp changes in seismic properties. This result highlights the potential of the methodology to image temporal variations of elastic properties in complex geomaterials, including the dramatic, localised changes associated with microcracking and damage generation.

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.

Ambient ammonia and related amines in and around a mink production facility

USDA-ARS?s Scientific Manuscript database

In areas where ammonia is a significant air pollutant or nuisance concern, knowledge of all potential source locations and strengths is paramount. The USEPA’s 2014 National Emissions Inventory estimates that nearly 80% of the national ammonia emissions are attributable to the agricultural sector an...

40 CFR 63.1406 - Reactor batch process vent provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions by...

40 CFR 63.1406 - Reactor batch process vent provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions by...

40 CFR 52.1183 - Visibility protection.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Regulation for visibility monitoring and new source review. The provisions of §§ 52.26 and 52.28 are hereby... Cement facility located in Charlevoix, Michigan, shall operate continuous emission monitoring systems to... section shall be use of a continuous emission monitoring system operated in conformance with 40 CFR part...

40 CFR 63.2131 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast What This... operate a nutritional yeast manufacturing facility that is, is located at, or is part of a major source of hazardous air pollutants (HAP) emissions. (1) A manufacturer of nutritional yeast is a facility that makes...

40 CFR 63.2131 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast What This... operate a nutritional yeast manufacturing facility that is, is located at, or is part of a major source of hazardous air pollutants (HAP) emissions. (1) A manufacturer of nutritional yeast is a facility that makes...

40 CFR 63.2131 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast What This... operate a nutritional yeast manufacturing facility that is, is located at, or is part of a major source of hazardous air pollutants (HAP) emissions. (1) A manufacturer of nutritional yeast is a facility that makes...

User's guide for RAM. Volume II. Data preparation and listings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, D.B.; Novak, J.H.

1978-11-01

The information presented in this user's guide is directed to air pollution scientists having an interest in applying air quality simulation models. RAM is a method of estimating short-term dispersion using the Gaussian steady-state model. These algorithms can be used for estimating air quality concentrations of relatively nonreactive pollutants for averaging times from an hour to a day from point and area sources. The algorithms are applicable for locations with level or gently rolling terrain where a single wind vector for each hour is a good approximation to the flow over the source area considered. Calculations are performed for eachmore » hour. Hourly meteorological data required are wind direction, wind speed, temperature, stability class, and mixing height. Emission information required of point sources consists of source coordinates, emission rate, physical height, stack diameter, stack gas exit velocity, and stack gas temperature. Emission information required of area sources consists of southwest corner coordinates, source side length, total area emission rate and effective area source-height. Computation time is kept to a minimum by the manner in which concentrations from area sources are estimated using a narrow plume hypothesis and using the area source squares as given rather than breaking down all sources into an area of uniform elements. Options are available to the user to allow use of three different types of receptor locations: (1) those whose coordinates are input by the user, (2) those whose coordinates are determined by the model and are downwind of significant point and area sources where maxima are likely to occur, and (3) those whose coordinates are determined by the model to give good area coverage of a specific portion of the region. Computation time is also decreased by keeping the number of receptors to a minimum. Volume II presents RAM example outputs, typical run streams, variable glossaries, and Fortran source codes.« less

40 CFR 55.7 - Exemptions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... offsets are not required in the COA, a new source shall comply with an offset ratio of 1:1. (iii) An existing OCS source shall comply with an offset at a ratio of 1:1. (3) An OCS source located beyond 25 miles from States' seaward boundaries shall obtain emission reductions at a ratio determined by the...

40 CFR 55.7 - Exemptions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... offsets are not required in the COA, a new source shall comply with an offset ratio of 1:1. (iii) An existing OCS source shall comply with an offset at a ratio of 1:1. (3) An OCS source located beyond 25 miles from States' seaward boundaries shall obtain emission reductions at a ratio determined by the...

40 CFR 55.7 - Exemptions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... offsets are not required in the COA, a new source shall comply with an offset ratio of 1:1. (iii) An existing OCS source shall comply with an offset at a ratio of 1:1. (3) An OCS source located beyond 25 miles from States' seaward boundaries shall obtain emission reductions at a ratio determined by the...

40 CFR 55.7 - Exemptions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... offsets are not required in the COA, a new source shall comply with an offset ratio of 1:1. (iii) An existing OCS source shall comply with an offset at a ratio of 1:1. (3) An OCS source located beyond 25 miles from States' seaward boundaries shall obtain emission reductions at a ratio determined by the...

Evaluation of the inverse dispersion modelling method for estimating ammonia multi-source emissions using low-cost long time averaging sensor

NASA Astrophysics Data System (ADS)

Loubet, Benjamin; Carozzi, Marco

2015-04-01

Tropospheric ammonia (NH3) is a key player in atmospheric chemistry and its deposition is a threat for the environment (ecosystem eutrophication, soil acidification and reduction in species biodiversity). Most of the NH3 global emissions derive from agriculture, mainly from livestock manure (storage and field application) but also from nitrogen-based fertilisers. Inverse dispersion modelling has been widely used to infer emission sources from a homogeneous source of known geometry. When the emission derives from different sources inside of the measured footprint, the emission should be treated as multi-source problem. This work aims at estimating whether multi-source inverse dispersion modelling can be used to infer NH3 emissions from different agronomic treatment, composed of small fields (typically squares of 25 m side) located near to each other, using low-cost NH3 measurements (diffusion samplers). To do that, a numerical experiment was designed with a combination of 3 x 3 square field sources (625 m2), and a set of sensors placed at the centre of each field at several heights as well as at 200 m away from the sources in each cardinal directions. The concentration at each sensor location was simulated with a forward Lagrangian Stochastic (WindTrax) and a Gaussian-like (FIDES) dispersion model. The concentrations were averaged over various integration times (3 hours to 28 days), to mimic the diffusion sampler behaviour with several sampling strategy. The sources were then inferred by inverse modelling using the averaged concentration and the same models in backward mode. The sources patterns were evaluated using a soil-vegetation-atmosphere model (SurfAtm-NH3) that incorporates the response of the NH3 emissions to surface temperature. A combination emission patterns (constant, linear decreasing, exponential decreasing and Gaussian type) and strengths were used to evaluate the uncertainty of the inversion method. Each numerical experiment covered a period of 28 days. The meteorological dataset of the fluxnet FR-Gri site (Grignon, FR) in 2008 was employed. Several sensor heights were tested, from 0.25 m to 2 m. The multi-source inverse problem was solved based on several sampling and field trial strategies: considering 1 or 2 heights over each field, considering the background concentration as known or unknown, and considering block-repetitions in the field set-up (3 repetitions). The inverse modelling approach demonstrated to be adapted for discriminating large differences in NH3 emissions from small agronomic plots using integrating sensors. The method is sensitive to sensor heights. The uncertainties and systematic biases are evaluated and discussed.

Constraining the location of rapid gamma-ray flares in the flat spectrum radio quasar 3C 273 [Constraining the location of rapid gamma-ray flares in the FSRQ 3C 273

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rani, B.; Lott, B.; Krichbaum, T. P.

2013-09-02

Here, we present a γ-ray photon flux and spectral variability study of the flat-spectrum radio quasar 3C 273 over a rapid flaring activity period between September 2009 to April 2010. Five major flares were observed in the source during this period. The most rapid flare observed in the source has a flux doubling time of 1.1 hr. The rapid γ-ray flares allow us to constrain the location and size of the γ-ray emission region in the source. The γγ-opacity constrains the Doppler factor δ γ ≥ 10 for the highest energy (15 GeV) photon observed by the Fermi-Large Area Telescopemore » (LAT). Causality arguments constrain the size of the emission region to 1.6 × 10 15 cm. The γ-ray spectra measured over this period show clear deviations from a simple power law with a break in the 1–2 GeV energy range. We discuss possible explanations for the origin of the γ-ray spectral breaks. Our study suggests that the γ-ray emission region in 3C 273 is located within the broad line region (< 1.6 pc). As a result, the spectral behavior and temporal characteristics of the individual flares indicate the presence of multiple shock scenarios at the base of the jet.« less

Anthropogenic fugitive, combustion and industrial dust is a significant, underrepresented fine particulate matter source in global atmospheric models

NASA Astrophysics Data System (ADS)

Philip, Sajeev; Martin, Randall V.; Snider, Graydon; Weagle, Crystal L.; van Donkelaar, Aaron; Brauer, Michael; Henze, Daven K.; Klimont, Zbigniew; Venkataraman, Chandra; Guttikunda, Sarath K.; Zhang, Qiang

2017-04-01

Global measurements of the elemental composition of fine particulate matter across several urban locations by the Surface Particulate Matter Network reveal an enhanced fraction of anthropogenic dust compared to natural dust sources, especially over Asia. We develop a global simulation of anthropogenic fugitive, combustion, and industrial dust which, to our knowledge, is partially missing or strongly underrepresented in global models. We estimate 2-16 μg m-3 increase in fine particulate mass concentration across East and South Asia by including anthropogenic fugitive, combustion, and industrial dust emissions. A simulation including anthropogenic fugitive, combustion, and industrial dust emissions increases the correlation from 0.06 to 0.66 of simulated fine dust in comparison with Surface Particulate Matter Network measurements at 13 globally dispersed locations, and reduces the low bias by 10% in total fine particulate mass in comparison with global in situ observations. Global population-weighted PM2.5 increases by 2.9 μg m-3 (10%). Our assessment ascertains the urgent need of including this underrepresented fine anthropogenic dust source into global bottom-up emission inventories and global models.

Near-source air pollution and mitigation strategies

EPA Science Inventory

Abstract. Local-scale air pollution impact is of concern for populations located in close proximity to transit sources, including highway, port, rail, and other areas of concentrated diesel emissions. Previous near-road air monitoring research has prompted the U.S. EPA to implem...

Source apportionment by PMF on elemental concentrations obtained by PIXE analysis of PM10 samples collected at the vicinity of lignite power plants and mines in Megalopolis, Greece

NASA Astrophysics Data System (ADS)

Manousakas, M.; Diapouli, E.; Papaefthymiou, H.; Migliori, A.; Karydas, A. G.; Padilla-Alvarez, R.; Bogovac, M.; Kaiser, R. B.; Jaksic, M.; Bogdanovic-Radovic, I.; Eleftheriadis, K.

2015-04-01

Particulate matter (PM) is an important constituent of atmospheric pollution especially in areas under the influence of industrial emissions. Megalopolis is a small city of 10,000 inhabitants located in central Peloponnese in close proximity to three coal opencast mines and two lignite fired power plants. 50 PM10 samples were collected in Megalopolis during the years 2009-11 for elemental and multivariate analysis. For the elemental analysis PIXE was used as one of the most effective techniques in APM analytical characterization. Altogether, the concentrations of 22 elements (Z = 11-33), whereas Black Carbon was also determined for each sample using a reflectometer. Factorization software was used (EPA PMF 3.0) for source apportionment analysis. The analysis revealed that major emission sources were soil dust 33% (7.94 ± 0.27 μg/m3), biomass burning 19% (4.43 ± 0.27 μg/m3), road dust 15% (3.63 ± 0.37 μg/m3), power plant emissions 13% (3.01 ± 0.44 μg/m3), traffic 12% (2.82 ± 0.37 μg/m3), and sea spray 8% (1.99 ± 0.41 μg/m3). Wind trajectories have suggested that metals associated with emission from the power plants came mainly from west and were connected with the locations of the lignite mines located in this area. Soil resuspension, road dust and power plant emissions increased during the warm season of the year, while traffic/secondary, sea spray and biomass burning become dominant during the cold season.

Assessing the Accuracy of the Tracer Dilution Method with Atmospheric Dispersion Modeling

NASA Astrophysics Data System (ADS)

Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

2015-12-01

Landfill methane emissions are difficult to estimate due to limited observations and data uncertainty. The mobile tracer dilution method is a widely used and cost-effective approach for predicting landfill methane emissions. The method uses a tracer gas released on the surface of the landfill and measures the concentrations of both methane and the tracer gas downwind. Mobile measurements are conducted with a gas analyzer mounted on a vehicle to capture transects of both gas plumes. The idea behind the method is that if the measurements are performed far enough downwind, the methane plume from the large area source of the landfill and the tracer plume from a small number of point sources will be sufficiently well-mixed to behave similarly, and the ratio between the concentrations will be a good estimate of the ratio between the two emissions rates. The mobile tracer dilution method is sensitive to different factors of the setup such as placement of the tracer release locations and distance from the landfill to the downwind measurements, which have not been thoroughly examined. In this study, numerical modeling is used as an alternative to field measurements to study the sensitivity of the tracer dilution method and provide estimates of measurement accuracy. Using topography and wind conditions for an actual landfill, a landfill emissions rate is prescribed in the model and compared against the emissions rate predicted by application of the tracer dilution method. Two different methane emissions scenarios are simulated: homogeneous emissions over the entire surface of the landfill, and heterogeneous emissions with a hot spot containing 80% of the total emissions where the daily cover area is located. Numerical modeling of the tracer dilution method is a useful tool for evaluating the method without having the expense and labor commitment of multiple field campaigns. Factors tested include number of tracers, distance between tracers, distance from landfill to transect path, and location of tracers with respect to the hot spot. Results show that location of the tracers relative to the hot spot of highest landfill emissions makes the largest difference in accuracy of the tracer dilution method.

40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed SI 4SRB Stationary RICE >500 HP...

Code of Federal Regulations, 2013 CFR

2013-07-01

..., New, and Reconstructed SI 4SRB Stationary RICE >500 HP Located at a Major Source of HAP Emissions 1b... Limitations for Existing, New, and Reconstructed SI 4SRB Stationary RICE >500 HP Located at a Major Source of... 15 percent O2 and using NSCR; a. maintain your catalyst so that the pressure drop across the catalyst...

40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed SI 4SRB Stationary RICE >500 HP...

Code of Federal Regulations, 2014 CFR

2014-07-01

..., New, and Reconstructed SI 4SRB Stationary RICE >500 HP Located at a Major Source of HAP Emissions 1b... Limitations for Existing, New, and Reconstructed SI 4SRB Stationary RICE >500 HP Located at a Major Source of... 15 percent O2 and using NSCR; a. maintain your catalyst so that the pressure drop across the catalyst...

Biomass Burning Emissions of Black Carbon from African Sources

NASA Astrophysics Data System (ADS)

Aiken, A. C.; Leone, O.; Nitschke, K. L.; Dubey, M. K.; Carrico, C.; Springston, S. R.; Sedlacek, A. J., III; Watson, T. B.; Kuang, C.; Uin, J.; McMeeking, G. R.; DeMott, P. J.; Kreidenweis, S. M.; Robinson, A. L.; Yokelson, R. J.; Zuidema, P.

2016-12-01

Biomass burning (BB) emissions are a large source of carbon to the atmosphere via particles and gas phase species. Carbonaceous aerosols are emitted along with gas-phase carbon monoxide (CO) and carbon dioxide (CO2) that can be used to determine particulate emission ratios and modified combustion efficiencies. Black carbon (BC) aerosols are potentially underestimated in global models and are considered to be one of the most important global warming factors behind CO2. Half or more BC in the atmosphere is from BB, estimated at 6-9 Tg/yr (IPCC, 5AR) and contributing up to 0.6 W/m2 atmospheric warming (Bond et al., 2013). With a potential rise in drought and extreme events in the future due to climate change, these numbers are expected to increase. For this reason, we focus on BC and organic carbon aerosol species that are emitted from forest fires and compare their emission ratios, physical and optical properties to those from controlled laboratory studies of single-source BB fuels to understand BB carbonaceous aerosols in the atmosphere. We investigate BC in concentrated BB plumes as sampled from the new U.S. DOE ARM Program campaign, Layered Atlantic Smoke Interactions with Clouds (LASIC). The ARM Aerosol Mobile Facility 1 (AMF1) and Mobile Aerosol Observing System (MAOS) are currently located on Ascension Island in the South Atlantic Ocean, located midway between Angola and Brazil. The location was chosen for sampling maximum aerosol outflow from Africa. The far-field aged BC from LASIC is compared to BC from indoor generation from single-source fuels, e.g. African grass, sampled during Fire Lab At Missoula Experiments IV (FLAME-IV). BC is measured with a single-particle soot photometer (SP2) alongside numerous supporting instrumentation, e.g. particle counters, CO and CO2 detectors, aerosol scattering and absorption measurements, etc. FLAME-IV includes both direct emissions and well-mixed aerosol samples that have undergone dilution, cooling, and condensation. BC physical and optical properties change as particles are transported in the atmosphere due to oxidation, coagulation, and condensation which is observed in the laboratory BC data. Laboratory BC emissions and emission ratios are compared with those from LASIC to improve model treatment of BB BC emissions and aging in global climate models.

Correlation of stress-wave-emission characteristics with fracture aluminum alloys

NASA Technical Reports Server (NTRS)

Hartbower, C. E.; Reuter, W. G.; Morais, C. F.; Crimmins, P. P.

1972-01-01

A study to correlate stress wave emission characteristics with fracture in welded and unwelded aluminum alloys tested at room and cryogenic temperature is reported. The stress wave emission characteristics investigated were those which serve to presage crack instability; viz., a marked increase in:(1) signal amplitude; (2) signal repetition rate; and (3) the slope of cumulative count plotted versus load. The alloys were 7075-T73, 2219-T87 and 2014-T651, welded with MIG and TIG using 2319 and 4043 filler wire. The testing was done with both unnotched and part-through-crack (PTC) tension specimens and with 18-in.-dia subscale pressure vessels. In the latter testing, a real time, acoustic emission, triangulation system was used to locate the source of each stress wave emission. With such a system, multiple emissions from a given location were correlated with defects found by conventional nondestructive inspection.

Infrasonic emissions from local meteorological events: A summary of data taken throughout 1984

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J.

1986-01-01

Records of infrasonic signals, propagating through the Earth's atmosphere in the frequency band 2 to 16 Hz, were gathered on a three microphone array at Langley Research Center throughout the year 1984. Digital processing of these records fulfilled three functions: time delay estimation, based on an adaptive filter; source location, determined from the time delay estimates; and source identification, based on spectral analysis. Meteorological support was provided by significant meteorological advisories, lightning locator plots, and daily reports from the Air Weather Service. The infrasonic data are organized into four characteristic signatures, one of which is believed to contain emissions from local meteorological sources. This class of signature prevailed only on those days when major global meteorological events appeared in or near to eastern United States. Eleven case histories are examined. Practical application of the infrasonic array in a low level wing shear alert system is discussed.

Calculated occultation profiles of Io and the hot spots

NASA Technical Reports Server (NTRS)

Mcewen, A. S.; Soderblom, L. A.; Matson, D. L.; Johnson, T. V.; Lunine, J. I.

1986-01-01

Occultations of Io by other Galilean satellites in 1985 provide a means to locate volcanic hot spots and to model their temperatures. The expected time variations in the integral reflected and emitted radiation of the occultations are computed as a function of wavelength (visual to 8.7 microns). The best current ephemerides were used to calculate the geometry of each event as viewed from earth. Visual reflectances were modeled from global mosaics of Io. Thermal emission from the hot spots was calculated from Voyager 1 IRIS observations and, for regions unobserved by IRIS, from a model based on the distribution of low-albedo features. The occultations may help determine (1) the location and temperature distribution of Loki; (2) the source(s) of excess emission in the region from long 50 deg to 200 deg and (3) the distribution of small, high-temperature sources.

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

... other health care 325411 facilities, commercial 325412 research laboratories, 562213 commercial waste... hearing is held, it will be held at EPA's Campus located at 109 T.W. Alexander Drive in Research Triangle... (E143-03), [[Page 27250

Trends in PM2.5 emissions, concentrations and apportionments in Detroit and Chicago

NASA Astrophysics Data System (ADS)

Milando, Chad; Huang, Lei; Batterman, Stuart

2016-03-01

PM2.5 concentrations throughout much of the U.S. have decreased over the last 15 years, but emissions and concentration trends can vary by location and source type. Such trends should be understood to inform air quality management and policies. This work examines trends in emissions, concentrations and source apportionments in two large Midwest U.S. cities, Detroit, Michigan, and Chicago, Illinois. Annual and seasonal trends were investigated using National Emission Inventory (NEI) data for 2002 to 2011, speciated ambient PM2.5 data from 2001 to 2014, apportionments from positive matrix factorization (PMF) receptor modeling, and quantile regression. Over the study period, county-wide data suggest emissions from point sources decreased (Detroit) or held constant (Chicago), while emissions from on-road mobile sources were constant (Detroit) or increased (Chicago), however changes in methodology limit the interpretation of inventory trends. Ambient concentration data also suggest source and apportionment trends, e.g., annual median concentrations of PM2.5 in the two cities declined by 3.2-3.6%/yr (faster than national trends), and sulfate concentrations (due to coal-fired facilities and other point source emissions) declined even faster; in contrast, organic and elemental carbon (tracers of gasoline and diesel vehicle exhaust) declined more slowly or held constant. The PMF models identified nine sources in Detroit and eight in Chicago, the most important being secondary sulfate, secondary nitrate and vehicle emissions. A minor crustal dust source, metals sources, and a biomass source also were present in both cities. These apportionments showed that the median relative contributions from secondary sulfate sources decreased by 4.2-5.5% per year in Detroit and Chicago, while contributions from metals sources, biomass sources, and vehicles increased from 1.3 to 9.2% per year. This first application of quantile regression to trend analyses of speciated PM2.5 data reveals that source contributions to PM2.5 varied as PM2.5 concentrations decreased, and that the fraction of PM2.5 due to emissions from vehicles and other local emissions has increased. Each data source has uncertainties, but emissions, monitoring and PMF data provide complementary information that can help to discern trends and identify contributing sources. Study results emphasize the need to target specific sources in policies and regulations aimed at decreasing PM2.5 concentrations in urban areas.

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 sources (13,500 kg/year), the emission rates of total B[a]Peq for cooking sources were much higher than those for traffic sources (61.4 kg/year). The above results clearly indicate that although cooking sources are less important than traffic sources in contributing to total PAH emissions, PAH emissions from cooking sources might cause much more serious problems than traffic sources, from the perspective of carcinogenic potency. PMID:12676603

Two reduced form air quality modeling techniques for rapidly calculating pollutant mitigation potential across many sources, locations and precursor emission types

EPA Science Inventory

Due to the computational cost of running regional-scale numerical air quality models, reduced form models (RFM) have been proposed as computationally efficient simulation tools for characterizing the pollutant response to many different types of emission reductions. The U.S. Envi...

Key issues in the design of NO{sub x} emission trading programs to reduce ground-level ozone. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nichols, A.; Harrison, D.

1994-07-01

This report is the first product of a study being conducted by National Economic Research Associates for the Electric Power Research Institute to evaluate various market-based alternatives for managing emissions of nitrogen oxides (NO{sub x}) as part of strategies to achieve the ambient ozone standard. The report focuses on choices in the design of relatively broad, ambitious emission trading programs, rather than on more modest programs designed to generate offsets within a regulatory framework that continues to rely primarily on traditional emission standards and nontransferable permits. After a brief introductory chapter, Chapter 2 reviews both the conceptual underpinnings of emissionmore » trading and prior experience. This review suggests the need for clear initial allocations-generally based on emission caps-to simplify trading while assuring the achievement of emission-reduction goals. Chapter 3 lays out the basic choices required in establishing an emission trading program. For concreteness, the basic design is discussed in terms of trading among utilities and other large stationary sources of NO{sub x}, generally the most promising candidates for trading. Chapter 4 discusses various ways in which a basic trading program could be extended to other source categories and to volatile organic compounds (VOCs), the other major precursor of ozone. Chapter 5 analyzes various ways in which trading programs can be refined to focus control efforts on those times and at those locations where ozone problems are most severe. Although highly refined targeting programs are unlikely to be worth the effort, modest differentials can be implemented by making the number of allowances required for each ton of emissions vary with the time and location of emissions. Chapter 6 reviews various alternatives for making the initial allocation of emission allowances among sources in the trading program, breaking the process into two components, an emission rate and an activity level.« less

Emissions of mercury from the power sector in Poland

NASA Astrophysics Data System (ADS)

Zyśk, J.; Wyrwa, A.; Pluta, M.

2011-01-01

Poland belongs to the European Union countries with the highest mercury emissions. This is mainly related to coal combustion. This paper presents estimates of mercury emissions from power sector in Poland. In this work, the bottom-up approach was applied and over 160 emission point sources were analysed. For each, the characteristics of the whole technological chain starting from fuel quality, boiler type as well as emission controls were taken into account. Our results show that emissions of mercury from brown coal power plants in 2005 were nearly four times greater than those of hard coal power plants. These estimates differ significantly from national statistics and some possible reasons are discussed. For the first time total mercury emissions from the Polish power sector were differentiated into its main atmospheric forms: gaseous elemental (GEM), reactive gaseous (RGM) and particulate-bound mercury. Information on emission source location and the likely vertical distribution of mercury emissions, which can be used in modelling of atmospheric dispersion of mercury is also provided.

Nitrogen isotopes as indicators of NOx source contributions to atmospheric nitrate deposition across the midwestern and northeastern United States

USGS Publications Warehouse

Elliott, E.M.; Kendall, C.; Wankel, Scott D.; Burns, Douglas A.; Boyer, E.W.; Harlin, K.; Bain, D.J.; Butler, T.J.

2007-01-01

Global inputs of NOx are dominated by fossil fuel combustion from both stationary and vehicular sources and far exceed natural NOx sources. However, elucidating NOx sources to any given location remains a difficult challenge, despite the need for this information to develop sound regulatory and mitigation strategies. We present results from a regional-scale study of nitrogen isotopes (??15N) in wet nitrate deposition across 33 sites in the midwestern and northeastern U.S. We demonstrate that spatial variations in ??15N are strongly correlated with NOx emissions from surrounding stationary sources and additionally that ??15N is more strongly correlated with surrounding stationary source NOx emissions than pH, SO 42-, or NO3- concentrations. Although emission inventories indicate that vehicle emissions are the dominant NOx source in the eastern U.S., our results suggest that wet NO 3- deposition at sites in this study is strongly associated with NOx emissions from stationary sources. This suggests that large areas of the landscape potentially receive atmospheric NOy deposition inputs in excess of what one would infer from existing monitoring data alone. Moreover, we determined that spatial patterns in ??15N values are a robust indicator of stationary NOx contributions to wet NO3- deposition and hence a valuable complement to existing tools for assessing relationships between NO 3- deposition, regional emission inventories, and for evaluating progress toward NOx reduction goals. ?? 2007 American Chemical Society.

AKARI Near-infrared Spectroscopy of the Extended Green Object G318.05+0.09: Detection of CO Fundamental Ro-vibrational Emission

NASA Astrophysics Data System (ADS)

Onaka, Takashi; Mori, Tamami; Sakon, Itsuki; Ardaseva, Aleksandra

2016-10-01

We present the results of near-infrared (2.5-5.4 μm) long-slit spectroscopy of the extended green object (EGO) G318.05+0.09 with AKARI. Two distinct sources are found in the slit. The brighter source has strong red continuum emission with H2O ice, CO2 ice, and CO gas and ice absorption features at 3.0, 4.25 μm, 4.67 μm, respectively, while the other greenish object shows peculiar emission that has double peaks at around 4.5 and 4.7 μm. The former source is located close to the ultra compact H II region IRAS 14498-5856 and is identified as an embedded massive young stellar object (YSO). The spectrum of the latter source can be interpreted by blueshifted (-3000 ˜ -6000 km s-1) optically thin emission of the fundamental ro-vibrational transitions (v=1{--}0) of CO molecules with temperatures of 12000-3700 K without noticeable H2 and H I emission. We discuss the nature of this source in terms of outflow associated with the young stellar object and supernova ejecta associated with a supernova remnant.

40 CFR 63.7985 - Am I subject to the requirements in this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...)(1) through (4) of this section. (1) Are located at or are part of a major source of hazardous air... as defined in § 63.8105. (3) Process, use, or produce HAP. (4) Are not part of an affected source...

40 CFR 63.7985 - Am I subject to the requirements in this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...)(1) through (4) of this section. (1) Are located at or are part of a major source of hazardous air... as defined in § 63.8105. (3) Process, use, or produce HAP. (4) Are not part of an affected source...

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.

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.

Preliminary Study on the Location Selection of Microalgae Cultivation In Nusa Tenggara Region As A Potential Feedstock For Bioavtur

NASA Astrophysics Data System (ADS)

Anggraini, Citrae Permata Kusuma; Sasongko, Nugroho Adi; Kuntjoro, Yanif Dwi

2018-02-01

NTT is a province located in strategic areas between Bali and South Sulawesi which has economic growth 5,08% in 2016. This causes air transportation in NTT to grow rapidly so the need for avtur is increased by 6% per year. To meet the needs of avtur in NTT would require energy diversification with bioavtur development in which one of them comes from microalgae. The content of lipid and hydrocarbon in microalgae can be used as a source of bioavtur feedstock. The suitability of location for cultivation will influence the success of microalgae cultivation that will be used as a source of bioavtur feedstock. The purpose of this research is to choose the best location for microalgae cultivation in NTT by AHP method. The criteria used in this research are nutrient, water and technology. Sub criteria of nutrient elements are coal power plant emission, cement industry emission and synthetic fertilizers, sub criteria from water that is sea water, brackish water and fresh water, while sub criteria of technology are Photobioreactor, Open Raceway Pond and membrane. The result of AHP analysis shows the selection of microalgae cultivation location in Kupang with the weight of 0.308, with the source of nutrient derived from coal power plant emission, the type of water used is sea water and the technology used is Photobioreactor. Microalgae species used were Nannochloropsis sp with a lipid content of 31-68%. Based on the author assumption, microalgae have the productivity for bioavtur manufacture which amount of 24.489kL/ha/ yr. That can be used to meet the needs of 2% avtur in NTT which amount of 1.052,22 kL/yr and the area requirement for microalgae cultivation is 2,14 hectare.

Discovery of an extended source of gamma-ray emission in the Southern hemisphere

NASA Astrophysics Data System (ADS)

Araya, Miguel

2018-02-01

We report the discovery of a ˜3.4°-wide region of high-energy emission in data from the Fermi LAT satellite. The centroid of the emission is located in the Southern hemisphere sky, a few degrees away from the plane of the Galaxy at the Galactic coordinates l = 350.6°, b = -4.7°. It shows a hard spectrum that is compatible with a simple power law, dN/dE∝ E^{-Γ }, in the energy range 0.7-500 GeV, with a spectral index Γ = 1.68 ± 0.04stat ± 0.1sys. The integrated source photon flux above 0.7 GeV is (4.71 ± 0.49stat ± 2.13sys) × 10-9 cm-2 s-1. We discuss several hypotheses for the nature of the source, particularly that the emission comes from the shell of an unknown supernova remnant.

Relation Between Sprite Distribution and Source Locations of VHF Pulses Derived From JEM- GLIMS Measurements

NASA Astrophysics Data System (ADS)

Sato, Mitsuteru; Mihara, Masahiro; Ushio, Tomoo; Morimoto, Takeshi; Kikuchi, Hiroshi; Adachi, Toru; Suzuki, Makoto; Yamazaki, Atsushi; Takahashi, Yukihiro

2015-04-01

JEM-GLIMS is continuing the comprehensive nadir observations of lightning and TLEs using optical instruments and electromagnetic wave receivers since November 2012. For the period between November 20, 2012 and November 30, 2014, JEM-GLIMS succeeded in detecting 5,048 lightning events. A total of 567 events in 5,048 lightning events were TLEs, which were mostly elves events. To identify the sprite occurrences from the transient optical flash data, it is necessary to perform the following data analysis: (1) a subtraction of the appropriately scaled wideband camera data from the narrowband camera data; (2) a calculation of intensity ratio between different spectrophotometer channels; and (3) an estimation of the polarization and CMC for the parent CG discharges using ground-based ELF measurement data. From a synthetic comparison of these results, it is confirmed that JEM-GLISM succeeded in detecting sprite events. The VHF receiver (VITF) onboard JEM-GLIMS uses two patch-type antennas separated by a 1.6-m interval and can detect VHF pulses emitted by lightning discharges in the 70-100 MHz frequency range. Using both an interferometric technique and a group delay technique, we can estimate the source locations of VHF pulses excited by lightning discharges. In the event detected at 06:41:15.68565 UT on June 12, 2014 over central North America, sprite was distributed with a horizontal displacement of 20 km from the peak location of the parent lightning emission. In this event, a total of 180 VHF pulses were simultaneously detected by VITF. From the detailed data analysis of these VHF pulse data, it is found that the majority of the source locations were placed near the area of the dim lightning emission, which may imply that the VHF pulses were associated with the in-cloud lightning current. At the presentation, we will show detailed comparison between the spatiotemporal characteristics of sprite emission and source locations of VHF pulses excited by the parent lightning discharges of sprites.

Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collier, Sonya; Zhou, Shan; Onasch, Timothy B.

Abstract Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, wildfire emissions in the Pacific Northwest region of the United States were characterized using real-time measurements near their sources using an aircraft, and farther downwind from a fixed ground site located at the Mt. Bachelor Observatory (~ 2700 m a.s.l.). The characteristics of aerosol emissions were found to depend strongly on the modified combustion efficiency (MCE), a qualitative index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereasmore » the carbon oxidation state of organic aerosol increased with MCE. The relationships between the aerosol properties and MCE were consistent between fresher emissions (~1 hour old) and emissions sampled after atmospheric transport (6 - 45 hours), suggesting that organic aerosol mass loading and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. These results suggest that MCE can be a useful metric for describing aerosol properties of regionally transported wildfire emissions and their impacts on regional air quality and global climate.« less

Prioritizing environmental justice and equality: diesel emissions in southern California.

PubMed

Marshall, Julian D; Swor, Kathryn R; Nguyen, Nam P

2014-04-01

Existing environmental policies aim to reduce emissions but lack standards for addressing environmental justice. Environmental justice research documents disparities in exposure to air pollution; however, little guidance currently exists on how to make improvements or on how specific emission-reduction scenarios would improve or deteriorate environmental justice conditions. Here, we quantify how emission reductions from specific sources would change various measures of environmental equality and justice. We evaluate potential emission reductions for fine diesel particulate matter (DPM) in Southern California for five sources: on-road mobile, off-road mobile, ships, trains, and stationary. Our approach employs state-of-the-science dispersion and exposure models. We compare four environmental goals: impact, efficiency, equality, and justice. Results indicate potential trade-offs among those goals. For example, reductions in train emissions produce the greatest improvements in terms of efficiency, equality, and justice, whereas off-road mobile source reductions can have the greatest total impact. Reductions in on-road emissions produce improvements in impact, equality, and justice, whereas emission reductions from ships would widen existing population inequalities. Results are similar for complex versus simplified exposure analyses. The approach employed here could usefully be applied elsewhere to evaluate opportunities for improving environmental equality and justice in other locations.

Measurements of Carbon Dioxide in the Portland, Oregon Metropolitan Region

NASA Astrophysics Data System (ADS)

Bostrom, G. A.; Rice, A. L.

2009-12-01

Urban centers provide large sources of carbon dioxide (CO2) to the atmosphere through intensive use of fossil fuels. Due to a lack of federal regulatory framework in the United States, a patchwork of regional and statewide approaches to reducing CO2 emissions has emerged. The City of Portland together with Multnomah County established itself as an early frontier in this regard by creating greenhouse gas emissions inventories in 1990 and adopting a regional plan to reduce emissions in 1993. Most recent emissions inventories suggest that County-wide emissions of CO2 are near 1990 levels, despite a growing population, with an ambitious goal of reducing emissions 80% by 2050. However, there has been no validation of either emissions inventories or their trends in time. Here, we detail preliminary results of a study aimed at testing regional CO2 emissions inventories through measurements of CO2 concentrations and its 13C isotopic composition. In collaboration with Oregon Department of Environmental Quality three test sites were established: a downtown Portland location on the campus of Portland State University; a residential Southeast Portland location; and at Sauvie Island, located ~30km northwest (upwind, rural) of Portland in the Columbia River Gorge. Continuous measurements of summertime CO2 concentrations since late July, 2009 range from approximately 370ppm to 420ppm (±2.7σ) for downtown and residential sites, and 360ppm to 420ppm for Sauvie Island, while maximum outlier levels at all three sites exceed 480ppm. Measurements at all three sites show a marked diurnal cycle averaging 25-35ppm. Maximum CO2 concentrations typically occur 6-8 am and minimum concentrations 5-7 pm. The two dominant forcing mechanisms of this strong diurnal cycle are varying biological sources and sinks and the dynamics of the planetary boundary layer. There is also a significant enhancement of ~7ppm in the average measured concentrations at the two urban sites (~395ppm) compared with the upwind Sauvie Island site (~388ppm). We interpret these results in terms of CO2 emissions inventories and sinks of CO2 in the Portland region. We also present preliminary measurements of the 13C isotopic composition of CO2 as a means of source apportionment with which to better refine emissions inventories.

Planar location of the simulative acoustic source based on fiber optic sensor array

NASA Astrophysics Data System (ADS)

Liang, Yi-Jun; Liu, Jun-feng; Zhang, Qiao-ping; Mu, Lin-lin

2010-06-01

A fiber optic sensor array which is structured by four Sagnac fiber optic sensors is proposed to detect and locate a simulative source of acoustic emission (AE). The sensing loops of Sagnac interferometer (SI) are regarded as point sensors as their small size. Based on the derived output light intensity expression of SI, the optimum work condition of the Sagnac fiber optic sensor is discussed through the simulation of MATLAB. Four sensors are respectively placed on a steel plate to structure the sensor array and the location algorithms are expatiated. When an impact is generated by an artificial AE source at any position of the plate, the AE signal will be detected by four sensors at different times. With the help of a single chip microcomputer (SCM) which can calculate the position of the AE source and display it on LED, we have implemented an intelligent detection and location.

Source Characterization of Volatile Organic Compounds Affecting the Air Quality in a Coastal Urban Area of South Texas

PubMed Central

Sanchez, Marciano; Karnae, Saritha; John, Kuruvilla

2008-01-01

Selected Volatile Organic Compounds (VOC) emitted from various anthropogenic sources including industries and motor vehicles act as primary precursors of ozone, while some VOC are classified as air toxic compounds. Significantly large VOC emission sources impact the air quality in Corpus Christi, Texas. This urban area is located in a semi-arid region of South Texas and is home to several large petrochemical refineries and industrial facilities along a busy ship-channel. The Texas Commission on Environmental Quality has setup two continuous ambient monitoring stations (CAMS 633 and 634) along the ship channel to monitor VOC concentrations in the urban atmosphere. The hourly concentrations of 46 VOC compounds were acquired from TCEQ for a comprehensive source apportionment study. The primary objective of this study was to identify and quantify the sources affecting the ambient air quality within this urban airshed. Principal Component Analysis/Absolute Principal Component Scores (PCA/APCS) was applied to the dataset. PCA identified five possible sources accounting for 69% of the total variance affecting the VOC levels measured at CAMS 633 and six possible sources affecting CAMS 634 accounting for 75% of the total variance. APCS identified natural gas emissions to be the major source contributor at CAMS 633 and it accounted for 70% of the measured VOC concentrations. The other major sources identified at CAMS 633 included flare emissions (12%), fugitive gasoline emissions (9%), refinery operations (7%), and vehicle exhaust (2%). At CAMS 634, natural gas sources were identified as the major source category contributing to 31% of the observed VOC. The other sources affecting this site included: refinery operations (24%), flare emissions (22%), secondary industrial processes (12%), fugitive gasoline emissions (8%) and vehicle exhaust (3%). PMID:19139530

Removal of Atmospheric Ethanol by Wet Deposition: A Global Flux Estimate

NASA Astrophysics Data System (ADS)

Felix, J. D. D.; Willey, J. D.; Avery, B.; Thomas, R.; Mullaugh, K.; Kieber, R. J.; Mead, R. N.; Helms, J. R.; Campos, L.; Shimizu, M. S.; Guibbina, F.

2017-12-01

Global ethanol fuel consumption has increased exponentially over the last two decades and the US plans to double annual renewable fuel production in the next five years as required by the renewable fuel standard. Regardless of the technology or feedstock used to produce the renewable fuel, the primary end product will be ethanol. Increasing ethanol fuel consumption will have an impact on the oxidizing capacity of the atmosphere and increase atmospheric concentrations of the secondary pollutant peroxyacetyl nitrate as well a variety of VOCs with relatively high ozone reactivities (e.g. ethanol, formaldehyde, acetaldehyde). Despite these documented effects of ethanol emissions on atmospheric chemistry, current global atmospheric ethanol budget models have large uncertainties in the magnitude of ethanol sources and sinks. The presented work investigates the global wet deposition sink by providing the first estimate of the global wet deposition flux of ethanol (2.4 ± 1.6 Tg/yr) based on empirical wet deposition data (219 samples collected at 12 locations). This suggests the wet deposition sink removes between 6 and 17% of atmospheric ethanol annually. Concentrations of ethanol in marine wet deposition (25 ± 6 nM) were an order of magnitude less than in the majority of terrestrial deposition (345 ± 280 nM). Terrestrial deposition collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to deposition collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources and ethanol emission impacts on air quality may be more significant in highly populated areas. As established and developing countries continue to rapidly increase ethanol fuel consumption and subsequent emissions, understanding the magnitude of all ethanol sources and sinks and impacts on the atmosphere is essential.

SCO X-1: Origin of the radio and hard X-ray emissions

NASA Technical Reports Server (NTRS)

Ramaty, R.; Cheng, C. C.; Tsuruta, S.

1973-01-01

The consequences of models for the central radio source and the hard X-ray ( 30 keV) emitting region in Sco X-1 are examined. It was found that the radio emission could result from noncoherent synchrotron radiation and that the X-rays may be produced by bremsstrahlung. It is shown that both mechanisms require a mass outflow from Sco X-1. The radio source is located at r approximately 3x10 to the 12th power cm from the center of the star, and its linear dimensions do not exceed 3x10 to the 13th power cm. The magnetic field in the radio source is on the order of 1 gauss. If the hard X-rays are produced by thermal bremsstrahlung, their source is located at 10 to the 9th power approximately r approximately 5x10 to the 9th power cm, the temperature is 2x10 to the 9th power K, and the emission measure is 2x10 to the 56th power/cu cm. This hot plasma loses energy inward by conduction and outward by supersonic expansion. The rates of energy loss for both processes are about 10 to the 36th power erg/s, comparable to the total luminosity of Sco X-1.

Implications of RCP emissions for future changes in vegetative exposure to ozone in the western U.S.

NASA Astrophysics Data System (ADS)

Lapina, Kateryna; Henze, Daven K.; Milford, Jana B.; Cuvelier, Cornelis; Seltzer, Michael

2015-05-01

Future changes in anthropogenic emissions of ozone precursors will likely impact seasonal vegetative ozone exposure, W126, in the western U.S. To investigate this, source-receptor relationships are calculated with the GEOS-Chem adjoint model and are separated by location, species, and sector. These are used to project changes in W126 through midcentury following representative concentration pathway (RCP) emissions. The overall behavior of W126 is governed by declining domestic emissions. However, foreign emissions of NOx, non-methane volatile organic compounds, and CO and CH4 abundance can either slow or enhance this trend, depending on scenario. The relative importance of foreign emissions increases as U.S. emissions decline, and, in some cases, the contribution of foreign sources exceeds that of domestic as early as 2020. In 2050, W126 in the western U.S. contributed by Chinese emissions alone, dominated by the industrial sector, is up to 15% higher than in 2000, although such estimates are strongly dependent on scenario.

Weekly agricultural emissions and ambient concentrations of ammonia: Validation of an emission inventory

NASA Astrophysics Data System (ADS)

Bittman, Shabtai; Jones, Keith; Vingarzan, Roxanne; Hunt, Derek E.; Sheppard, Steve C.; Tait, John; So, Rita; Zhao, Johanna

2015-07-01

Weekly inventories for emissions of agricultural ammonia were calculated for 139 4 × 4 km grid cells over 52 weeks in the intensely farmed Lower Fraser Valley, BC. The grid cells were located both inside and outside an area that had been depopulated of poultry due to an outbreak of Avian Influenza prior to the start of the study. During the study period, ambient ammonia concentrations were measured hourly at two locations outside the cull area and one location inside the cull area. Large emission differences between grid cells and differences in temporal variation between cells were related to farming practices and meteorological factors such as temperature and rainfall. Weekly average ambient concentrations at the three sampling locations were significantly correlated with estimates of weekly emissions for many of the grid cells in the study area. Inside the cull area, ambient concentrations during the cull (week 1) were 37% of the concentrations after the cull (week 52), while outside the cull there was almost no difference between week 1 and week 52, suggesting that in normal (non-cull) conditions, about 60% of the ambient ammonia was due to poultry farms. Estimated emissions in weeks 1 and 52 for grid cells affected by the cull indicated that over 90% of the emissions came from poultry. The discrepancy in difference between week 1 and 52 for emissions and ambient concentrations could be due to atmospheric factors like transport, atmospheric reactions, dispersion or deposition; to errors in the inventory including farming data, emission factors; and omission of some non-poultry emission sources. Overall the study supports the ammonia emission inventory estimates. Detailed emission data helps in modeling ammonia in the atmosphere and is useful for developing abatement policy.

Monitoring fossil fuel sources of methane in Australia

NASA Astrophysics Data System (ADS)

Loh, Zoe; Etheridge, David; Luhar, Ashok; Hibberd, Mark; Thatcher, Marcus; Noonan, Julie; Thornton, David; Spencer, Darren; Gregory, Rebecca; Jenkins, Charles; Zegelin, Steve; Leuning, Ray; Day, Stuart; Barrett, Damian

2017-04-01

CSIRO has been active in identifying and quantifying methane emissions from a range of fossil fuel sources in Australia over the past decade. We present here a history of the development of our work in this domain. While we have principally focused on optimising the use of long term, fixed location, high precision monitoring, paired with both forward and inverse modelling techniques suitable either local or regional scales, we have also incorporated mobile ground surveys and flux calculations from plumes in some contexts. We initially developed leak detection methodologies for geological carbon storage at a local scale using a Bayesian probabilistic approach coupled to a backward Lagrangian particle dispersion model (Luhar et al. JGR, 2014), and single point monitoring with sector analysis (Etheridge et al. In prep.) We have since expanded our modelling techniques to regional scales using both forward and inverse approaches to constrain methane emissions from coal mining and coal seam gas (CSG) production. The Surat Basin (Queensland, Australia) is a region of rapidly expanding CSG production, in which we have established a pair of carefully located, well-intercalibrated monitoring stations. These data sets provide an almost continuous record of (i) background air arriving at the Surat Basin, and (ii) the signal resulting from methane emissions within the Basin, i.e. total downwind methane concentration (comprising emissions including natural geological seeps, agricultural and biogenic sources and fugitive emissions from CSG production) minus background or upwind concentration. We will present our latest results on monitoring from the Surat Basin and their application to estimating methane emissions.

Emission Sectoral Contributions of Foreign Emissions to Particulate Matter Concentrations over South Korea

NASA Astrophysics Data System (ADS)

Kim, E.; Kim, S.; Kim, H. C.; Kim, B. U.; Cho, J. H.; Woo, J. H.

2017-12-01

In this study, we investigated the contributions of major emission source categories located upwind of South Korea to Particulate Matter (PM) in South Korea. In general, air quality in South Korea is affected by anthropogenic air pollutants emitted from foreign countries including China. Some studies reported that foreign emissions contributed 50 % of annual surface PM total mass concentrations in the Seoul Metropolitan Area, South Korea in 2014. Previous studies examined PM contributions of foreign emissions from all sectors considering meteorological variations. However, little studies conducted to assess contributions of specific foreign source categories. Therefore, we attempted to estimate sectoral contributions of foreign emissions from China to South Korea PM using our air quality forecasting system. We used Model Inter-Comparison Study in Asia 2010 for foreign emissions and Clean Air Policy Support System 2010 emission inventories for domestic emissions. To quantify contributions of major emission sectors to South Korea PM, we applied the Community Multi-scale Air Quality system with brute force method by perturbing emissions from industrial, residential, fossil-fuel power plants, transportation, and agriculture sectors in China. We noted that industrial sector was pre-dominant over the region except during cold season for primary PMs when residential emissions drastically increase due to heating demand. This study will benefit ensemble air quality forecasting and refined control strategy design by providing quantitative assessment on seasonal contributions of foreign emissions from major source categories.

An Overview of Three-year JEM-GLIMS Nadir Observations of Lightning and TLEs

NASA Astrophysics Data System (ADS)

Sato, M.; Ushio, T.; Morimoto, T.; Adachi, T.; Kikuchi, H.; Suzuki, M.; Yamazaki, A.; Takahashi, Y.; Inan, U.; Linscott, I.; Hobara, Y.

2015-12-01

JEM-GLIMS nadir observations of lightning and TLEs at the ISS started from November 2012 and successfully ended on August 2015. For three-year observation period, JEM-GLIMS succeeded in detecting over 8,000 lightning events and 670 TLEs. The detected optical emissions of sprites showed clear horizontal displacement with the range of 10-20 km from the peak location of the +CG emissions and from the +CG locations detected by NLDN and WWLLN. Using VITF electric field waveform data, source locations of VHF pulses excited by the parent CG discharges are estimated. It is found that the possible VHF source locations were mostly located within the area of the parent lightning emissions. These facts may imply that the center region of the neutralized charge by CG discharges in the thundercloud located near the return stroke point and that the some seed conditions were established in advance at the sprite location before the occurrence of sprites. The global occurrence distributions and rates of lightning discharges and TLEs are also estimated. The estimated mean global occurrence rate of lightning discharges is ~1.5 events/s, which is smaller number than that derived from MicroLab-1/OTD and TRMM/LIS measurements. This may be originated in the fact that JEM-GLISM detected only intense lightning optical events due to the high threshold level for the event triggering. To the contrary, the estimated mean global occurrence rate of TLEs is ~9.8 events/min, which is two times higher than the ISUAL result. It is likely that JEM-GLIMS could detect dimmer optical emissions of TLEs than ISUAL since the distance between the JEM-GLIMS instruments and TLEs is much closer. At the presentation, we will summarize the results derived from three-year JEM-GLIMS nadir observations. We will discuss possible occurrence conditions of sprites, properties of global occurrence rates of lightning and TLEs, and their LT dependences more in detail.

40 CFR 70.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... section 183(f) of the Act; (11) Any standard or other requirement of the program to control air pollution... emissions which could not reasonably pass through a stack, chimney, vent, or other functionally-equivalent... means any stationary source (or any group of stationary sources that are located on one or more...

EFFECT OF SAMPLING LOCATION ON CONCENTRATION IN LARGE CHAMBER INVESTIGATION OF EMISSIONS FROM MARKERS

EPA Science Inventory

Markers were selected for evaluation in this study because (1) they are widely used in schools, offices, and homes; (2) they are a known source of volatile organic compounds (VOCs) in nonoccupational indoor environments; and (3) according to the Source Ranking Database developed ...

Acoustic emission testing on an F/A-18 E/F titanium bulkhead

NASA Astrophysics Data System (ADS)

Martin, Christopher A.; Van Way, Craig B.; Lockyer, Allen J.; Kudva, Jayanth N.; Ziola, Steve M.

1995-04-01

An important opportunity recently transpired at Northrop Grumman Corporation to instrument an F/A - 18 E/F titanium bulkhead with broad band acoustic emission sensors during a scheduled structural fatigue test. The overall intention of this effort was to investigate the potential for detecting crack propagation using acoustic transmission signals for a large structural component. Key areas of experimentation and experience included (1) acoustic noise characterization, (2) separation of crack signals from extraneous noise, (3) source location accuracy, and (4) methods of acoustic transducer attachment. Fatigue cracking was observed and monitored by strategically placed acoustic emission sensors. The outcome of the testing indicated that accurate source location still remains enigmatic for non-specialist engineering personnel especially at this level of structural complexity. However, contrary to preconceived expectations, crack events could be readily separated from extraneous noise. A further dividend from the investigation materialized in the form of close correspondence between frequency domain waveforms of the bulkhead test specimen tested and earlier work with thick plates.

Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT

NASA Astrophysics Data System (ADS)

Hanabata, Y.; Katagiri, H.; Hewitt, J. W.; Ballet, J.; Fukazawa, Y.; Fukui, Y.; Hayakawa, T.; Lemoine-Goumard, M.; Pedaletti, G.; Strong, A. W.; Torres, D. F.; Yamazaki, R.

2014-05-01

We present a detailed investigation of the γ-ray emission in the vicinity of the supernova remnant (SNR) W28 (G6.4-0.1) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. We detected significant γ-ray emission spatially coincident with TeV sources HESS J1800-240A, B, and C, located outside the radio boundary of the SNR. Their spectra in the 2-100 GeV band are consistent with the extrapolation of the power-law spectra of the TeV sources. We also identified a new source of GeV emission, dubbed Source W, which lies outside the boundary of TeV sources and coincides with radio emission from the western part of W28. All of the GeV γ-ray sources overlap with molecular clouds in the velocity range from 0 to 20 km s-1. Under the assumption that the γ-ray emission toward HESS J1800-240A, B, and C comes from π0 decay due to the interaction between the molecular clouds and cosmic rays (CRs) escaping from W28, they can be naturally explained by a single model in which the CR diffusion coefficient is smaller than the theoretical expectation in the interstellar space. The total energy of the CRs escaping from W28 is constrained through the same modeling to be larger than ~2 × 1049 erg. The emission from Source W can also be explained with the same CR escape scenario.

Detailed Investigation of the Gamma-Ray Emission in the Vicinity of SNR W28 with FERMI-LAT

NASA Technical Reports Server (NTRS)

Hanabata, Y.; Katagiri, H.; Hewitt, John William; Ballet, J.; Fukazawa, Y.; Fukui, Y.; Hayakawa, T.; Lemoine-Goumard, M.; Pedaletti, G.; Strong, A. W.;

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benkovitz, C.M.

Sulfur emissions from volcanoes are located in areas of volcanic activity, are extremely variable in time, and can be released anywhere from ground level to the stratosphere. Previous estimates of global sulfur emissions from all sources by various authors have included estimates for emissions from volcanic activity. In general, these global estimates of sulfur emissions from volcanoes are given as global totals for an ``average`` year. A project has been initiated at Brookhaven National Laboratory to compile inventories of sulfur emissions from volcanoes. In order to complement the GEIA inventories of anthropogenic sulfur emissions, which represent conditions circa specific years,more » sulfur emissions from volcanoes are being estimated for the years 1985 and 1990.« less

ANS hard X-ray experiment development program. [emission from X-ray sources

NASA Technical Reports Server (NTRS)

Parsignault, D.; Gursky, H.; Frank, R.; Kubierschky, K.; Austin, G.; Paganetti, R.; Bawdekar, V.

1974-01-01

The hard X-ray (HXX) experiment is one of three experiments included in the Dutch Astronomical Netherlands Satellite, which was launched into orbit on 30 August 1974. The overall objective of the HXX experiment is the detailed study of the emission from known X-ray sources over the energy range 1.5-30keV. The instrument is capable of the following measurements: (1) spectral content over the full energy range with an energy resolution of approximately 20% and time resolution down to 4 seconds; (2) source time variability down to 4 milliseconds; (3) silicon emission lines at 1.86 and 2.00keV; (4) source location to a limit of one arc minute in ecliptic latitude; and (5) spatial structure with angular resolution of the arc minutes. Scientific aspects of experiment, engineering design and implementation of the experiment, and program history are included.

Differences Between Magnitudes and Health Impacts of BC Emissions Across the United States Using 12 km Scale Seasonal Source Apportionment

EPA Science Inventory

Recent assessments have analyzed the health impacts of PM2.5 from emissions from different locations and sectors using simplified or reduced-form air quality models. Here we present an alternative approach using the adjoint of the Community Multiscale Air Quality (CMAQ) model, wh...

40 CFR Table 6 to Subpart Zzzz of... - Continuous Compliance With Emission Limitations, and Other Requirements

Code of Federal Regulations, 2014 CFR

2014-07-01

... >500 HP located at a major source of HAP a. Reduce CO emissions and using an oxidation catalyst, and... not using an oxidation catalyst, and using a CPMS i. Conducting semiannual performance tests for CO to... RICE exhaust and using oxidation catalyst or NSCR i. Conducting semiannual performance tests for...

40 CFR Table 6 to Subpart Zzzz of... - Continuous Compliance With Emission Limitations, and Other Requirements

Code of Federal Regulations, 2013 CFR

2013-07-01

... >500 HP located at a major source of HAP a. Reduce CO emissions and using an oxidation catalyst, and... not using an oxidation catalyst, and using a CPMS i. Conducting semiannual performance tests for CO to... RICE exhaust and using oxidation catalyst or NSCR i. Conducting semiannual performance tests for...

40 CFR Table 6 to Subpart Zzzz of... - Continuous Compliance With Emission Limitations and Operating Limitations

Code of Federal Regulations, 2010 CFR

2010-07-01

... stationary RICE >500 HP located at a major source a. Reduce CO emissions and using an oxidation catalyst, and... percent reduction is achieved a; and ii. Collecting the catalyst inlet temperature data according to § 63... rolling averages within the operating limitations for the catalyst inlet temperature; and v. Measuring the...

Quantification of uncertainty associated with United States high resolution fossil fuel CO2 emissions: updates, challenges and future plans

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Chandrasekaran, V.; Mendoza, D. L.; Geethakumar, S.

2010-12-01

The Vulcan Project has estimated United States fossil fuel CO2 emissions at the hourly time scale and at spatial scales below the county level for the year 2002. Vulcan is built from a wide variety of observational data streams including regulated air pollutant emissions reporting, traffic monitoring, energy statistics, and US census data. In addition to these data sets, Vulcan relies on a series of modeling assumptions and constructs to interpolate in space, time and transform non-CO2 reporting into an estimate of CO2 combustion emissions. The recent version 2.0 of the Vulcan inventory has produced advances in a number of categories with particular emphasis on improved temporal structure. Onroad transportation emissions now avail of roughly 5000 automated traffic count monitors allowing for much improved diurnal and weekly time structure in our onroad transportation emissions. Though the inventory shows excellent agreement with independent national-level CO2 emissions estimates, uncertainty quantification has been a challenging task given the large number of data sources and numerous modeling assumptions. However, we have now accomplished a complete uncertainty estimate across all the Vulcan economic sectors and will present uncertainty estimates as a function of space, time, sector and fuel. We find that, like the underlying distribution of CO2 emissions themselves, the uncertainty is also strongly lognormal with high uncertainty associated with a relatively small number of locations. These locations typically are locations reliant upon coal combustion as the dominant CO2 source. We will also compare and contrast Vulcan fossil fuel CO2 emissions estimates against estimates built from DOE fuel-based surveys at the state level. We conclude that much of the difference between the Vulcan inventory and DOE statistics are not due to biased estimation but mechanistic differences in supply versus demand and combustion in space/time.

Numerical simulations for the sources apportionment and control strategies of PM2.5 over Pearl River Delta, China, part I: Inventory and PM2.5 sources apportionment.

PubMed

Huang, Yeqi; Deng, Tao; Li, Zhenning; Wang, Nan; Yin, Chanqin; Wang, Shiqiang; Fan, Shaojia

2018-09-01

This article uses the WRF-CMAQ model to systematically study the source apportionment of PM 2.5 under typical meteorological conditions in the dry season (November 2010) in the Pearl River Delta (PRD). According to the geographical location and the relative magnitude of pollutant emission, Guangdong Province is divided into eight subdomains for source apportionment study. The Brute-Force Method (BFM) method was implemented to simulate the contribution from different regions to the PM 2.5 pollution in the PRD. Results show that the industrial sources accounted for the largest proportion. For emission species, the total amount of NO x and VOC in Guangdong Province, and NH 3 and VOC in Hunan Province are relatively larger. In Guangdong Province, the emission of SO 2 , NO x and VOC in the PRD are relatively larger, and the NH 3 emissions are higher outside the PRD. In northerly-controlled episodes, model simulations demonstrate that local emissions are important for PM 2.5 pollution in Guangzhou and Foshan. Meanwhile, emissions from Dongguan and Huizhou (DH), and out of Guangdong Province (SW) are important contributors for PM 2.5 pollution in Guangzhou. For PM 2.5 pollution in Foshan, emissions in Guangzhou and DH are the major contributors. In addition, high contribution ratio from DH only occurs in severe pollution periods. In southerly-controlled episode, contribution from the southern PRD increases. Local emissions and emissions from Shenzhen, DH, Zhuhai-Jiangmen-Zhongshan (ZJZ) are the major contributors. Regional contribution to the chemical compositions of PM 2.5 indicates that the sources of chemical components are similar to those of PM 2.5 . In particular, SO 4 2- is mainly sourced from emissions out of Guangdong Province, while the NO 3- and NH 4+ are more linked to agricultural emissions. Copyright © 2018 Elsevier B.V. All rights reserved.

Mapping methane emissions using the airborne imaging spectrometer AVIRIS-NG

NASA Astrophysics Data System (ADS)

Thorpe, A. K.; Frankenberg, C.; Thompson, D. R.; Duren, R. M.; Bue, B. D.; Green, R. O.

2017-12-01

The next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) has been used to survey large regions and map methane plumes with unambiguous identification of emission source locations. This capability is aided by real time detection and geolocation of gas plumes, permitting adaptive surveys and communication to ground teams for rapid follow up. We present results from AVIRIS-NG flight campaigns in Colorado, New Mexico, and California. Hundreds of plumes were observed, reflecting emissions from the energy sector that include hydraulic fracturing, gas processing plants, tanks, pumpjacks, and pipeline leaks. In some cases, plumes observed by AVIRIS-NG resulted in mitigation. Additional examples will be shown for methane from dairy lagoons, landfills, natural emissions, as well as carbon dioxide from power plants and refineries. We describe the unique capabilities of airborne imaging spectrometers to augment other measurement techniques by efficiently surveying key regions for methane point sources and supporting timely assessment and mitigation. We summarize the outlook for near- and longer-term monitoring capabilities including future satellite systems. Figure caption. AVIRIS-NG true color image subset with superimposed methane plume showing retrieved gas concentrations. Plume extends 200 m downwind of the southern edge of the well pad. Google Earth imagery with finer spatial resolution is also included (red box), indicating that tanks in the inset scene as the source of emissions. Five wells are located at the center of this well pad and all use horizontal drilling to produce mostly natural gas.

Husbandry Emissions at the Sub-Facility Scale by Fused Mobile Surface In Situ and Airborne Remote Sensing

NASA Astrophysics Data System (ADS)

Leifer, I.; Melton, C.; Tratt, D. M.; Hall, J. L.; Buckland, K. N.; Frash, J.; Leen, J. B.; Lundquist, T.; Vigil, S. A.

2017-12-01

Husbandry methane (CH4) and ammonia (NH3) are strong climate and air pollution drivers. Husbandry emission factors have significant uncertainty and can differ from lab estimates as real-world practices affect emissions including where and how husbandry activities occur, their spatial and temporal relationship to micro-climate (winds, temperature, insolation, rain, and lagoon levels, which vary diurnally and seasonally), and animal care. Research dairies provide a unique opportunity to combine insights on sub-facility scale emissions to identify best practices. Two approaches with significant promise for quantifying husbandry emissions are airborne remote sensing and mobile in situ trace gas with meteorological measurements. Both capture snapshot data to allow deconvolution of temporal and spatial variability, which challenges stationary measurements, while also capturing micro-scale processes, allowing connection of real-world practices to emissions. Mobile in situ concentration data on trace gases and meteorology were collected by AMOG (AutoMObile trace Gas) Surveyor on 10 days spanning 31 months at the California Polytechnic State University Research Dairy, San Luis Obispo, CA. AMOG Surveyor is a commuter vehicle modified for atmospheric science. CH4, NH3, H2O, COS, CO, CO2, H2S, O3, NO, NO2, SO2, NOX, solar spectra, temperature, and winds were measured. The airborne hyperspectral thermal infrared sensor, Mako, collected data on 28 Sept. 2015. Research dairies allow combining insights on sub-facility scale emissions to identify best practices holistically - i.e., considering multiple trace gases. In situ data were collected while transecting plumes, approximately orthogonal to winds. Emission strength and source location were estimated by Gaussian plume inversion, validated by airborne data. Good agreement was found on source strength and location at meter length-scales. Data revealed different activities produced unique emissions with distinct trace gas fingerprints - for example, a mostly empty holding lagoon (LE, Fig. 1) was a stronger H2S source than a full holding lagoon (LW, Fig. 1), and an area in a corral (S1, Fig. 1) where cows congregated was a strong, focused NH3 source. Mako data mapped out micro-scale variability in transport that agreed with AMOG winds and plume inversions.

Anthropogenic emissions of nonmethane hydrocarbons in the northeastern United States: Measured seasonal variations from 1992-1996 and 1999-2001

NASA Astrophysics Data System (ADS)

Lee, Ben H.; Munger, J. William; Wofsy, Steven C.; Goldstein, Allen H.

2006-10-01

Harvard Forest, a rural site located in central Massachusetts downwind of major urban-industrial centers, provides an excellent location to observe a typical regional mixture of anthropogenic trace gases. Air that arrives at Harvard Forest from the southwest is affected by emissions from the U.S. east coast urban corridor and may have residual influence from emissions in the upper Ohio Valley and Great Lakes region farther to the west. Because of its relatively long distance from large individual emission sources, pollution plumes reaching the site are a homogenized mixture of regional anthropogenic emissions. Concentrations of C2-C6 hydrocarbons along with CO and NOy were measured nearly continuously from August 1992 through July 1996 and from June 1999 through November 2001. By correlating observed concentrations to acetylene, which is almost solely produced during combustion, we are able to detect seasonal trends in relative emissions for this series of trace gases. Seasonal changes in n-butane and i-butane emissions may largely be influenced by different gasoline formulations in late spring and summer. Shifts in evaporation rates due to the annual temperature cycle could induce a seasonal pattern for n-pentane, i-pentane and n-hexane emissions. Emissions of ethane and propane lack clear seasonality relative to acetylene emissions and also correlate less with acetylene than other gases, indicating that emissions of these two gases are strongly influenced by sources not associated with fuel combustion. Changes in the observed correlations of CO2 and CO relative to acetylene are consistent with published changes in the estimated emissions of CO2 and CO over the past decade, though variability in the observations makes it difficult to precisely quantify these changes.

Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

NASA Astrophysics Data System (ADS)

Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

2008-12-01

Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of combustion-derived PM and BC to the atmosphere and have started to replace coal as the major source in some surficial reservoirs. This increased urban influence of gasoline and diesel combustion on BC emissions was also observed in Europe both from model estimates as well as from measured fluxes in recent lake sediments.

Impact assessment of biomass-based district heating systems in densely populated communities. Part II: Would the replacement of fossil fuels improve ambient air quality and human health?

NASA Astrophysics Data System (ADS)

Petrov, Olga; Bi, Xiaotao; Lau, Anthony

2017-07-01

To determine if replacing fossil fuel combustion with biomass gasification would impact air quality, we evaluated the impact of a small-scale biomass gasification plant (BRDF) at a university campus over 5 scenarios. The overall incremental contribution of fine particles (PM2.5) is found to be at least one order of magnitude lower than the provincial air quality objectives. The maximum PM2.5 emission from the natural gas fueled power house (PH) could adversely add to the already high background concentration levels. Nitrogen dioxide (NO2) emissions from the BRDF with no engineered pollution controls for NOx in place exceeded the provincial objective in all seasons except during summer. The impact score, IS, was the highest for NO2 (677 Disability Adjusted Life Years, DALY) when biomass entirely replaced fossil fuels, and the highest for PM2.5 (64 DALY) and CO (3 DALY) if all energy was produced by natural gas at PH. Complete replacement of fossil fuels by one biomass plant can result in almost 28% higher health impacts (708 DALY) compared to 513 DALY when both the current BRDF and the PH are operational mostly due to uncontrolled NO2 emissions. Observations from this study inform academic community, city planners, policy makers and technology developers on the impacts of community district heating systems and possible mitigation strategies: a) community energy demand could be met either by splitting emissions into more than one source at different locations and different fuel types or by a single source with the least-impact-based location selection criteria with biomass as a fuel; b) advanced high-efficiency pollution control devices are essential to lower emissions for emission sources located in a densely populated community; c) a spatial and temporal impact assessment should be performed in developing bioenergy-based district heating systems, in which the capital and operational costs should be balanced with not only the benefit to greenhouse gas emission reduction but also the health impact to the local community.

Sources and sinks of selected trace gases in the tropospheric boundary layer of the eastern United States

NASA Astrophysics Data System (ADS)

White, Marguerite L.

This dissertation describes three major research projects with the common goal of characterizing sources and sinks of trace gases of strong relevance to regional air quality and global climate issues. In the first study, volatile organic compound (VOC) measurements collected at a marine and continental site in northern New England were compared and examined for evidence of regional VOC sources. Biogenic VOCs, including isoprene, monoterpenes, and oxygenated VOCs, were significant components of the total reactivity at both locations. However, very different VOC distributions were observed for each site. The impact of local anthropogenic hydrocarbon sources such as liquefied petroleum gas (LPG) leakage was also evident at both sites. During the campaign, a propane flux of 9 (+/-2) x 109 molecules cm-2 s-1 was calculated for the continental site. In the second study, three hydrocarbon sources were investigated for their potential contributions to the summertime atmospheric toluene enhancements observed at a rural location in southern New Hampshire. These sources included: (1) warm season fuel evaporation emissions, (2) local industrial emissions, and (3) local vegetative emissions. The estimated contribution of fuel evaporation emissions (16-30 pptv d-1) could not fully account for observed summertime toluene enhancements (20-50 pptv d-1). Vegetation enclosure measurements suggested biogenic toluene emissions (5 and 12 pptv d-1 for alfalfa and pine trees) made significant contributions to summertime enhancements. Industrial toluene emissions, estimated at 7 pptv d-1, most likely occurred year round rather than seasonally. Finally, controls over carbonyl sulfide (COS) uptake in a temperate loblolly pine forest grown under ambient and elevated CO2 were examined in the third study. Vegetative consumption dominated net ecosystem COS uptake (10 to 40 pmol m-2 s-1) under both CO2 regimes. Environmental controls over vegetation stomatal conductance and photosynthetic capacity were the major factors influencing COS uptake rates. The loblolly pines exhibited substantial COS consumption overnight (50% of daytime rates) that was independent of CO2 assimilation. This suggests current estimates of the global vegetative COS sink, which assume that COS and CO2 are consumed simultaneously, may need to be reevaluated.

Atmospheric aerosols in Rome, Italy: sources, dynamics and spatial variations during two seasons

NASA Astrophysics Data System (ADS)

Struckmeier, Caroline; Drewnick, Frank; Fachinger, Friederike; Gobbi, Gian Paolo; Borrmann, Stephan

2016-12-01

Investigations on atmospheric aerosols and their sources were carried out in October/November 2013 and May/June 2014 consecutively in a suburban area of Rome (Tor Vergata) and in central Rome (near St Peter's Basilica). During both years a Saharan dust advection event temporarily increased PM10 concentrations at ground level by about 12-17 µg m-3. Generally, in October/November the ambient aerosol was more strongly influenced by primary emissions, whereas higher relative contributions of secondary particles (sulfate, aged organic aerosol) were found in May/June. Absolute concentrations of anthropogenic emission tracers (e.g. NOx, CO2, particulate polycyclic aromatic hydrocarbons, traffic-related organic aerosol) were generally higher at the urban location. Positive matrix factorization was applied to the PM1 organic aerosol (OA) fraction of aerosol mass spectrometer (HR-ToF-AMS) data to identify different sources of primary OA (POA): traffic, cooking, biomass burning and (local) cigarette smoking. While biomass burning OA was only found at the suburban site, where it accounted for the major fraction of POA (18-24 % of total OA), traffic and cooking were more dominant sources at the urban site. A particle type associated with cigarette smoke emissions, which is associated with a potential characteristic marker peak (m/z 84, C5H10N+, a nicotine fragment) in the mass spectrum, was only found in central Rome, where it was emitted in close vicinity to the measurement location. Regarding secondary OA, in October/November, only a very aged, regionally advected oxygenated OA was found, which contributed 42-53 % to the total OA. In May/June total oxygenated OA accounted for 56-76 % of the OA. Here a fraction (18-26 % of total OA) of a fresher, less oxygenated OA of more local origin was also observed. New particle formation events were identified from measured particle number concentrations and size distributions in May/June 2014 at both sites. While they were observed every day at the urban location, at the suburban location they were only found under favourable meteorological conditions, but were independent of advection of the Rome emission plume. Particles from sources in the metropolitan area of Rome and particles advected from outside Rome contributed 42-70 and 30-58 % to the total measured PM1, respectively. Apart from the general aerosol characteristics, in this study the properties (e.g. emission strength) and dynamics (e.g. temporal behaviour) of each identified aerosol type is investigated in detail to provide a better understanding of the observed seasonal and spatial differences.

Localizing sources of acoustic emission during the martensitic transformation

NASA Astrophysics Data System (ADS)

Niemann, R.; Kopeček, J.; Heczko, O.; Romberg, J.; Schultz, L.; Fähler, S.; Vives, E.; Mañosa, L.; Planes, A.

2014-06-01

Acoustic avalanches are a general feature of solids under stress, e.g., evoked by external compression or arising from internal processes like martensitic phase transformations. From integral measurements, it is usually concluded that nucleation, phase boundary pinning, or interface incompatibilities during this first-order phase transition all may generate acoustic emission. This paper studies the local sources of acoustic emission to enlight the microscopic mechanisms. From two-dimensional spatially resolved acoustic emission measurement and simultaneous optical observation of the surface, we can identify microstructural events at the phase boundary that lead to acoustic emission. A resolution in the 100-μm range was reached for the location of acoustic emission sources on a coarse-grained Ni-Mn-Ga polycrystal. Both, the acoustic activity and the size distribution of the microstructural transformation events, exhibit power-law behavior. The origin of the acoustic emission are elastically incompatible areas, such as differently oriented martensitic plates that meet each other, lamellae growing up to grain boundaries, and grain boundaries in proximity to transforming grains. Using this result, we propose a model to explain the decrease of the critical exponent under a mechanical stress or magnetic field.

ROSAT PSPC and HRI observations of the composite starburst/Seyfert 2 galaxy NGC 1672

NASA Technical Reports Server (NTRS)

Brandt, W. N.; Halpern, Jules P.; Iwasawa, K.

1995-01-01

The nearby barred spiral galaxy NGC 1672 has been observed with the Position Sensitive Proportional Counter (PSPC) and High Resolution Imager (HRI) instruments on board the ROSAT X-ray satellite. NGC 1672 is thought to have an obscured Seyfert nucleus, and it has strong starburst activity as well. Three bright X-ray sources with luminosities 1-2 x 10(exp 40) erg/s are clearly identified with NGC 1672. The strongest lies at the nucleus, and the other two lie at the ends of NGC 1672's prominent bar, locations that are also bright in H alpha and near-infrared images. The nuclear source is resolved by the HRI on about the scale of the recently identified nuclear ring, and one of the sources at the ends of the bar is also probably resolved. The X-ray spectrum of the nuclear source is quite soft, having a Raymond-Smith plasma temperature of approximately equals 0.7 keV and little evidence for intrinsic absorption. The ROSAT band X-ray flux of the nuclear source appears to be dominated not by X-ray binary emission but rather by diffuse gas emission. The absorption and emission properties of the sources, as well as their spatial extents, lead us to models of superbubbles driven by supernovae. However, the large density and emission measure of the nuclear X-ray source stretch the limits that can be comfortably accommodated by these models. We do not detect direct emission from the putative Seyfert nucleus, although an alternative model for the nuclear source is thermal emission from gas that is photoionized by a hidden Seyfert nucleus. The spectra of the other two X-ray sources are harder than that of the nuclear source, and have similar difficulties with regard to superbubble models.

76 FR 15607 - National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-21

...On September 13, 2004, under authority of section 112 of the Clean Air Act, EPA promulgated national emission standards for hazardous air pollutants for new and existing industrial/commercial/ institutional boilers and process heaters. On June 19, 2007, the United States Court of Appeals for the District of Columbia Circuit vacated and remanded the standards. In response to the Court's vacatur and remand, EPA is, in this action, establishing emission standards that will require industrial/ commercial/institutional boilers and process heaters located at major sources to meet hazardous air pollutants standards reflecting the application of the maximum achievable control technology. This rule protects air quality and promotes public health by reducing emissions of the hazardous air pollutants listed in section 112(b)(1) of the Clean Air Act.

Estimating State-Specific Contributions to PM2.5- and O3-Related Health Burden from Residential Combustion and Electricity Generating Unit Emissions in the United States.

PubMed

Penn, Stefani L; Arunachalam, Saravanan; Woody, Matthew; Heiger-Bernays, Wendy; Tripodis, Yorghos; Levy, Jonathan I

2017-03-01

Residential combustion (RC) and electricity generating unit (EGU) emissions adversely impact air quality and human health by increasing ambient concentrations of fine particulate matter (PM 2.5 ) and ozone (O 3 ). Studies to date have not isolated contributing emissions by state of origin (source-state), which is necessary for policy makers to determine efficient strategies to decrease health impacts. In this study, we aimed to estimate health impacts (premature mortalities) attributable to PM 2.5 and O 3 from RC and EGU emissions by precursor species, source sector, and source-state in the continental United States for 2005. We used the Community Multiscale Air Quality model employing the decoupled direct method to quantify changes in air quality and epidemiological evidence to determine concentration-response functions to calculate associated health impacts. We estimated 21,000 premature mortalities per year from EGU emissions, driven by sulfur dioxide emissions forming PM 2.5 . More than half of EGU health impacts are attributable to emissions from eight states with significant coal combustion and large downwind populations. We estimate 10,000 premature mortalities per year from RC emissions, driven by primary PM 2.5 emissions. States with large populations and significant residential wood combustion dominate RC health impacts. Annual mortality risk per thousand tons of precursor emissions (health damage functions) varied significantly across source-states for both source sectors and all precursor pollutants. Our findings reinforce the importance of pollutant-specific, location-specific, and source-specific models of health impacts in design of health-risk minimizing emissions control policies. Citation: Penn SL, Arunachalam S, Woody M, Heiger-Bernays W, Tripodis Y, Levy JI. 2017. Estimating state-specific contributions to PM 2.5 - and O 3 -related health burden from residential combustion and electricity generating unit emissions in the United States. Environ Health Perspect 125:324-332; http://dx.doi.org/10.1289/EHP550.

Approach to identifying pollutant source and matching flow field

NASA Astrophysics Data System (ADS)

Liping, Pang; Yu, Zhang; Hongquan, Qu; Tao, Hu; Wei, Wang

2013-07-01

Accidental pollution events often threaten people's health and lives, and it is necessary to identify a pollutant source rapidly so that prompt actions can be taken to prevent the spread of pollution. But this identification process is one of the difficulties in the inverse problem areas. This paper carries out some studies on this issue. An approach using single sensor information with noise was developed to identify a sudden continuous emission trace pollutant source in a steady velocity field. This approach first compares the characteristic distance of the measured concentration sequence to the multiple hypothetical measured concentration sequences at the sensor position, which are obtained based on a source-three-parameter multiple hypotheses. Then we realize the source identification by globally searching the optimal values with the objective function of the maximum location probability. Considering the large amount of computation load resulting from this global searching, a local fine-mesh source search method based on priori coarse-mesh location probabilities is further used to improve the efficiency of identification. Studies have shown that the flow field has a very important influence on the source identification. Therefore, we also discuss the impact of non-matching flow fields with estimation deviation on identification. Based on this analysis, a method for matching accurate flow field is presented to improve the accuracy of identification. In order to verify the practical application of the above method, an experimental system simulating a sudden pollution process in a steady flow field was set up and some experiments were conducted when the diffusion coefficient was known. The studies showed that the three parameters (position, emission strength and initial emission time) of the pollutant source in the experiment can be estimated by using the method for matching flow field and source identification.

Source-to-exposure assessment with the Pangea multi-scale framework - case study in Australia.

PubMed

Wannaz, Cedric; Fantke, Peter; Lane, Joe; Jolliet, Olivier

2018-01-24

Effective planning of airshed pollution mitigation is often constrained by a lack of integrative analysis able to relate the relevant emitters to the receptor populations at risk. Both emitter and receptor perspectives are therefore needed to consistently inform emission and exposure reduction measures. This paper aims to extend the Pangea spatial multi-scale multimedia framework to evaluate source-to-receptor relationships of industrial sources of organic pollutants in Australia. Pangea solves a large compartmental system in parallel by block to determine arrays of masses at steady-state for 100 000+ compartments and 4000+ emission scenarios, and further computes population exposure by inhalation and ingestion. From an emitter perspective, radial spatial distributions of population intakes show high spatial variation in intake fractions from 0.68 to 33 ppm for benzene, and from 0.006 to 9.5 ppm for formaldehyde, contrasting urban, rural, desert, and sea source locations. Extending analyses to the receptor perspective, population exposures from the combined emissions of 4101 Australian point sources are more extended for benzene that travels over longer distances, versus formaldehyde that has a more local impact. Decomposing exposure per industrial sector shows petroleum and steel industry as the highest contributing industrial sectors for benzene, whereas the electricity sector and petroleum refining contribute most to formaldehyde exposures. The source apportionment identifies the main sources contributing to exposure at five locations. Overall, this paper demonstrates high interest in addressing exposures from both an emitter perspective well-suited to inform product oriented approaches such as LCA, and from a receptor perspective for health risk mitigation.

Arctic Black Carbon Initiative: Reducing Emissions of Black Carbon from Power & Industry in Russia

NASA Astrophysics Data System (ADS)

Cresko, J.; Hodson, E. L.; Cheng, M.; Fu, J. S.; Huang, K.; Storey, J.

2012-12-01

Deposition of black carbon (BC) on snow and ice is widely considered to have a climate warming effect by reducing the surface albedo and promoting snowmelt. Such positive climate feedbacks in the Arctic are especially problematic because rising surface temperatures may trigger the release of large Arctic stores of terrestrial carbon, further amplifying current warming trends. Recognizing the Arctic as a vulnerable region, the U.S. government committed funds in Copenhagen in 2009 for international cooperation targeting Arctic BC emissions reductions. As a result, the U.S. Department of State has funded three research and demonstration projects with the goal to better understand and mitigate BC deposition in the Russian Arctic from a range of sources. The U.S. Department of Energy's (DOE) Arctic BC initiative presented here is focused on mitigating BC emissions resulting from heat and power generation as well as industrial applications. A detailed understanding of BC sources and its transport and fate is required to prioritize efforts to reduce BC emissions from sources that deposit in the Russian Arctic. Sources of BC include the combustion of fossil fuels (e.g. coal, fuel oil, diesel) and the combustion of biomass (e.g. wildfires, agricultural burning, residential heating and cooking). Information on fuel use and associated emissions from the industrial and heat & power sectors in Russia is scarce and difficult to obtain from the open literature. Hence, our project includes a research component designed to locate Arctic BC emissions sources in Russia and determine associated BC transport patterns. We use results from the research phase to inform a subsequent assessment/demonstration phase. We use a back-trajectory modeling method (potential source contribution function - PSCF), which combines multi-year, high-frequency measurements with knowledge about atmospheric transport patterns. The PSCF modeling allows us to map the probability (by season and year) at course resolution (2.5° x 2.5° spatial resolution) that a particular region emits BC which deposits in the Russian Arctic. We utilize data from three Arctic measurement stations during the most recent decade: Alert, Northwest Territories, Canada; Barrow, Alaska; and Tiksi Bay, Russia. To understand more about individual Arctic BC sources, we conduct further research to improve inventory estimates of Russian industrial and energy sector BC emissions. By comparing inventory data on power plant locations and emissions from two publically-available databases (EDGAR-HTAP and CARMA databases) to each other and to additional observations from satellites and the AERONET observation network in Russia, we assess the accuracy of the Russian BC emission inventory in EDGAR-HTAP, a commonly used database for atmospheric transport modeling. We then use a global (GEOS-CHEM) atmospheric transport model to quantify the finer spatial distribution of BC within the Arctic. Lastly, we use data on Russian fuel use combined with published emissions factors to build a national-scale model of energy use and associated emissions from critical industrial and heat & power sources of BC. We use this model to estimate the technical potential of reducing BC emissions through proven mitigation efforts such as improvements in energy efficiency and in emission control technologies.

Modeling mobile source emissions during traffic jams in a micro urban environment.

PubMed

Kondrashov, Valery V; Reshetin, Vladimir P; Regens, James L; Gunter, James T

2002-01-01

Urbanization typically involves a continuous increase in motor vehicle use, resulting in congestion known as traffic jams. Idling emissions due to traffic jams combine with the complex terrain created by buildings to concentrate atmospheric pollutants in localized areas. This research simulates emissions concentrations and distributions for a congested street in Minsk, Belarus. Ground-level (up to 50-meters above the street's surface) pollutant concentrations were calculated using STAR (version 3.10) with emission factors obtained from the U.S. Environmental Protection Agency, wind speed and direction, and building location and size. Relative emissions concentrations and distributions were simulated at 1-meter and 10-meters above street level. The findings demonstrate the importance of wind speed and direction, and building size and location on emissions concentrations and distributions, with the leeward sides of buildings retaining up to 99 percent of the emitted pollutants within 1-meter of street level, and up to 77 percent 10-meters above the street.

Ray tracing study of rising tone EMIC-triggered emissions

NASA Astrophysics Data System (ADS)

Hanzelka, Miroslav; Santolík, Ondřej; Grison, Benjamin; Cornilleau-Wehrlin, Nicole

2017-04-01

ElectroMagnetic Ion Cyclotron (EMIC) triggered emissions have been subject of extensive theoretical and experimental research in last years. These emissions are characterized by high coherence values and a frequency range of 0.5 - 2.0 Hz, close to local helium gyrofrequency. We perform ray tracing case studies of rising tone EMIC-triggered emissions observed by the Cluster spacecraft in both nightside and dayside regions off the equatorial plane. By comparison of simulated and measured wave properties, namely wave vector orientation, group velocity, dispersion and ellipticity of polarization, we determine possible source locations. Diffusive equilibrium density model and other, semi-empirical models are used with ion composition inferred from cross-over frequencies. Ray tracing simulations are done in cold plasma approximation with inclusion of Landau and cyclotron damping. Various widths, locations and profiles of plasmapause are tested.

Contribution of biogenic emissions to the formation of ozone and particulate matter in the eastern United States.

PubMed

Pun, Betty K; Wu, Shiang-Yuh; Seigneur, Christian

2002-08-15

As anthropogenic emissions of ozone (O3) precursors, fine particulate matter (PM2.5), and PM2.5 precursors continue to decrease in the United States, the fraction of O3 and PM2.5 attributable to natural sources may become significant in some locations, reducing the efficacy that can be expected from future controls of anthropogenic sources. Modeling studies were conducted to estimate the contribution of biogenic emissions to the formation of O3 and PM2.5 in Nashville/TN and the northeastern United States. Two approaches were used to bound the estimates. In an anthropogenic simulation, biogenic emissions and their influence at the domain boundaries were eliminated. Contributions of biogenic compounds to the simulated concentrations of O3 and PM2.5 were determined by the deviation of the concentrations in the anthropogenic case from those in the base case. A biogenic simulation was used to assess the amounts of O3 and PM2.5 produced in an environment free from anthropogenic influences in emissions and boundary conditions. In both locations, the contribution of biogenic emissions to O3 was small (<23%) on a domain-wide basis, despite significant biogenic volatile organic compounds (VOC) emissions (65-89% of total VOC emissions). However, the production of O3 was much more sensitive to biogenic emissions in urban areas (22-34%). Therefore, the effects of biogenic emissions on O3 manifested mostly via their interaction with anthropogenic emissions of NOx. In the anthropogenic simulations, the average contribution of biogenic and natural sources to PM2.5 was estimated at 9% in Nashville/TN and 12% in the northeast domain. Because of the long atmospheric lifetimes of PM2.5, the contribution of biogenic/natural PM2.5 from the boundary conditions was higher than the contribution of biogenic aerosols produced within the domain. The elimination of biogenic emissions also affected the chemistry of other secondary PM2.5 components. Very little PM2.5 was formed in the biogenic simulations.

Quantification of methane and nitrous oxide emissions from various waste treatment facilities by tracer dilution method

NASA Astrophysics Data System (ADS)

Mønster, Jacob; Rella, Chris; Jacobson, Gloria; Kjeldsen, Peter; Scheutz, Charlotte

2013-04-01

Urban activities generate solid and liquid waste, and the handling and aftercare of the waste results in the emission of various compounds into the surrounding environment. Some of these compounds are emitted as gasses into the atmosphere, including methane and nitrous oxide. Methane and nitrous oxide are strong greenhouse gases and are considered to have 25 and 298 times the greenhouse gas potential of carbon dioxide on a hundred years term (Solomon et al. 2007). Global observations of both gasses have shown increasing concentrations that significantly contribute to the greenhouse gas effect. Methane and nitrous oxide are emitted from both natural and anthropogenic sources and inventories of source specific fugitive emissions from the anthropogenic sources of methane and nitrous oxide of are often estimated on the basis of modeling and mass balance. Though these methods are well-developed, actual measurements for quantification of the emissions is a very useful tool for verifying the modeling and mass balance as well as for validation initiatives done for lowering the emissions of methane and nitrous oxide. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001, Scheutz et al. 2011), where the exact location of the source is located and a tracer gas is released at this source location at a known flow. The ratio of downwind concentrations of the tracer gas and the methane and nitrous oxide gives the emissions rates of the greenhouse gases. This tracer dilution method can be performed using both stationary and mobile measurements and in both cases, real-time measurements of both tracer and quantified gas are required, placing high demands on the analytical detection method. To perform the methane and nitrous oxide measurements, two robust instruments capable of real-time measurements were used, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. One instrument measured the methane and tracer gas concentrations while another measured the nitrous oxide concentration. We present the performance of these instruments at different waste treatment facilities (waste water treatment plants, composting facilities, sludge mineralization beds, anaerobic digesters and landfills) in Denmark, and discuss the strengths and limitations of the method of the method for quantifying methane and nitrous oxide emissions from the different sources. Furthermore, we have measured the methane emissions from 10 landfills with emission rates ranging from 5 to 135 kg/h depending on the age, state, content and aftercare of the landfill. In addition, we have studied 3 waste water treatment plants, and found nitrous oxide emission of 200 to 700 g/h from the aeration tanks and a total methane emission ranging from 2 to 15 kg/h, with the primary emission coming from the sludge treatment. References Galle, B., Samuelsson, J., Svensson, B.H., and Börjesson, G. (2001). Measurements of methane emissions from landfills using a time correlation tracer method based on FTIR absorption spectroscopy. Environmental Science & Technology 35 (1), 21-25 Scheutz, C., Samuelsson, J., Fredenslund, A. M., and Kjeldsen, P. (2011). Quantification of multiple methane emission sources at landfills using a double tracer technique. Waste Management, 31(5), 1009-17 Solomon, S., D. Qin, M. Manning, R.B. Alley, T. Berntsen, N.L. Bindoff, Z. Chen, A. Chidthaisong, J.M. Gregory, G.C. Hegerl, M. Heimann, B. Hewitson, B.J. Hoskins, F. Joos, J. Jouzel, V. Kattsov, U. Lohmann, T.Matsuno, M. Molina, N. Nicholls, J.Overpeck, G. Raga, V. Ramaswamy, J. Ren, M. Rusticucci, R. Somerville, T.F. Stocker, P. Whetton, R.A.Wood and D. Wratt, 2007: Technical Summary. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Acoustic Location of Lightning Using Interferometric Techniques

NASA Astrophysics Data System (ADS)

Erives, H.; Arechiga, R. O.; Stock, M.; Lapierre, J. L.; Edens, H. E.; Stringer, A.; Rison, W.; Thomas, R. J.

2013-12-01

Acoustic arrays have been used to accurately locate thunder sources in lightning flashes. The acoustic arrays located around the Magdalena mountains of central New Mexico produce locations which compare quite well with source locations provided by the New Mexico Tech Lightning Mapping Array. These arrays utilize 3 outer microphones surrounding a 4th microphone located at the center, The location is computed by band-passing the signal to remove noise, and then computing the cross correlating the outer 3 microphones with respect the center reference microphone. While this method works very well, it works best on signals with high signal to noise ratios; weaker signals are not as well located. Therefore, methods are being explored to improve the location accuracy and detection efficiency of the acoustic location systems. The signal received by acoustic arrays is strikingly similar to th signal received by radio frequency interferometers. Both acoustic location systems and radio frequency interferometers make coherent measurements of a signal arriving at a number of closely spaced antennas. And both acoustic and interferometric systems then correlate these signals between pairs of receivers to determine the direction to the source of the received signal. The primary difference between the two systems is the velocity of propagation of the emission, which is much slower for sound. Therefore, the same frequency based techniques that have been used quite successfully with radio interferometers should be applicable to acoustic based measurements as well. The results presented here are comparisons between the location results obtained with current cross correlation method and techniques developed for radio frequency interferometers applied to acoustic signals. The data were obtained during the summer 2013 storm season using multiple arrays sensitive to both infrasonic frequency and audio frequency acoustic emissions from lightning. Preliminary results show that interferometric techniques have good potential for improving the lightning location accuracy and detection efficiency of acoustic arrays.

Emitter location errors in electronic recognition system

NASA Astrophysics Data System (ADS)

Matuszewski, Jan; Dikta, Anna

2017-04-01

The paper describes some of the problems associated with emitter location calculations. This aspect is the most important part of the series of tasks in the electronic recognition systems. The basic tasks include: detection of emission of electromagnetic signals, tracking (determining the direction of emitter sources), signal analysis in order to classify different emitter types and the identification of the sources of emission of the same type. The paper presents a brief description of the main methods of emitter localization and the basic mathematical formulae for calculating their location. The errors' estimation has been made to determine the emitter location for three different methods and different scenarios of emitters and direction finding (DF) sensors deployment in the electromagnetic environment. The emitter has been established using a special computer program. On the basis of extensive numerical calculations, the evaluation of precise emitter location in the recognition systems for different configuration alignment of bearing devices and emitter was conducted. The calculations which have been made based on the simulated data for different methods of location are presented in the figures and respective tables. The obtained results demonstrate that calculation of the precise emitter location depends on: the number of DF sensors, the distances between emitter and DF sensors, their mutual location in the reconnaissance area and bearing errors. The precise emitter location varies depending on the number of obtained bearings. The higher the number of bearings, the better the accuracy of calculated emitter location in spite of relatively high bearing errors for each DF sensor.

40 CFR 96.76 - Additional requirements to provide heat input data for allocations purposes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Monitoring and Reporting § 96.76 Additional requirements... to monitor and report NOX Mass emissions using a NOX concentration system and a flow system shall... chapter for any source located in a state developing source allocations based upon heat input. (b) The...

40 CFR 63.6590 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Existing spark ignition 2 stroke lean burn (2SLB) stationary RICE with a site rating of more than 500 brake HP located at a major source of HAP emissions; (ii) Existing spark ignition 4 stroke lean burn (4SLB... emissions; (4) A new or reconstructed spark ignition 4 stroke rich burn (4SRB) stationary RICE with a site...

40 CFR 63.6590 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Existing spark ignition 2 stroke lean burn (2SLB) stationary RICE with a site rating of more than 500 brake HP located at a major source of HAP emissions; (ii) Existing spark ignition 4 stroke lean burn (4SLB... emissions; (4) A new or reconstructed spark ignition 4 stroke rich burn (4SRB) stationary RICE with a site...

Statistical atmospheric inversion of local gas emissions by coupling the tracer release technique and local-scale transport modelling: a test case with controlled methane emissions

NASA Astrophysics Data System (ADS)

Ars, Sébastien; Broquet, Grégoire; Yver Kwok, Camille; Roustan, Yelva; Wu, Lin; Arzoumanian, Emmanuel; Bousquet, Philippe

2017-12-01

This study presents a new concept for estimating the pollutant emission rates of a site and its main facilities using a series of atmospheric measurements across the pollutant plumes. This concept combines the tracer release method, local-scale atmospheric transport modelling and a statistical atmospheric inversion approach. The conversion between the controlled emission and the measured atmospheric concentrations of the released tracer across the plume places valuable constraints on the atmospheric transport. This is used to optimise the configuration of the transport model parameters and the model uncertainty statistics in the inversion system. The emission rates of all sources are then inverted to optimise the match between the concentrations simulated with the transport model and the pollutants' measured atmospheric concentrations, accounting for the transport model uncertainty. In principle, by using atmospheric transport modelling, this concept does not strongly rely on the good colocation between the tracer and pollutant sources and can be used to monitor multiple sources within a single site, unlike the classical tracer release technique. The statistical inversion framework and the use of the tracer data for the configuration of the transport and inversion modelling systems should ensure that the transport modelling errors are correctly handled in the source estimation. The potential of this new concept is evaluated with a relatively simple practical implementation based on a Gaussian plume model and a series of inversions of controlled methane point sources using acetylene as a tracer gas. The experimental conditions are chosen so that they are suitable for the use of a Gaussian plume model to simulate the atmospheric transport. In these experiments, different configurations of methane and acetylene point source locations are tested to assess the efficiency of the method in comparison to the classic tracer release technique in coping with the distances between the different methane and acetylene sources. The results from these controlled experiments demonstrate that, when the targeted and tracer gases are not well collocated, this new approach provides a better estimate of the emission rates than the tracer release technique. As an example, the relative error between the estimated and actual emission rates is reduced from 32 % with the tracer release technique to 16 % with the combined approach in the case of a tracer located 60 m upwind of a single methane source. Further studies and more complex implementations with more advanced transport models and more advanced optimisations of their configuration will be required to generalise the applicability of the approach and strengthen its robustness.

Mercury deposition in snow near an industrial emission source in the western U.S. and comparison to ISC3 model predictions

USGS Publications Warehouse

Abbott, M.L.; Susong, D.D.; Krabbenhoft, D.P.; Rood, A.S.

2002-01-01

Mercury (total and methyl) was evaluated in snow samples collected near a major mercury emission source on the Idaho National Engineering and Environmental Laboratory (INEEL) in southeastern Idaho and 160 km downwind in Teton Range in western Wyoming. The sampling was done to assess near-field (<12 km) deposition rates around the source, compare them to those measured in a relatively remote, pristine downwind location, and to use the measurements to develop improved, site-specific model input parameters for precipitation scavenging coefficient and the fraction of Hg emissions deposited locally. Measured snow water concentrations (ng L-1) were converted to deposition (ug m-2) using the sample location snow water equivalent. The deposition was then compared to that predicted using the ISC3 air dispersion/deposition model which was run with a range of particle and vapor scavenging coefficient input values. Accepted model statistical performance measures (fractional bias and normalized mean square error) were calculated for the different modeling runs, and the best model performance was selected. Measured concentrations close to the source (average = 5.3 ng L-1) were about twice those measured in the Teton Range (average = 2.7 ng L-1) which were within the expected range of values for remote background areas. For most of the sampling locations, the ISC3 model predicted within a factor of two of the observed deposition. The best modeling performance was obtained using a scavenging coefficient value for 0.25 ??m diameter particulate and the assumption that all of the mercury is reactive Hg(II) and subject to local deposition. A 0.1 ??m particle assumption provided conservative overprediction of the data, while a vapor assumption resulted in highly variable predictions. Partitioning a fraction of the Hg emissions to elemental Hg(0) (a U.S. EPA default assumption for combustion facility risk assessments) would have underpredicted the observed fallout.

Diagnostic Air Quality Model Evaluation of Source-Specific ...

EPA Pesticide Factsheets

Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004–February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of −0.55 μgC/m3 was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (−0.46 μgC/m3 on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others. The National Exposure Research L

Diagnostic air quality model evaluation of source-specific primary and secondary fine particulate carbon.

PubMed

Napelenok, Sergey L; Simon, Heather; Bhave, Prakash V; Pye, Havala O T; Pouliot, George A; Sheesley, Rebecca J; Schauer, James J

2014-01-01

Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004-February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of -0.55 μgC/m(3) was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (-0.46 μgC/m(3) on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others.

A quantitative acoustic emission study on fracture processes in ceramics based on wavelet packet decomposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ning, J. G.; Chu, L.; Ren, H. L., E-mail: huilanren@bit.edu.cn

2014-08-28

We base a quantitative acoustic emission (AE) study on fracture processes in alumina ceramics on wavelet packet decomposition and AE source location. According to the frequency characteristics, as well as energy and ringdown counts of AE, the fracture process is divided into four stages: crack closure, nucleation, development, and critical failure. Each of the AE signals is decomposed by a 2-level wavelet package decomposition into four different (from-low-to-high) frequency bands (AA{sub 2}, AD{sub 2}, DA{sub 2}, and DD{sub 2}). The energy eigenvalues P{sub 0}, P{sub 1}, P{sub 2}, and P{sub 3} corresponding to these four frequency bands are calculated. Bymore » analyzing changes in P{sub 0} and P{sub 3} in the four stages, we determine the inverse relationship between AE frequency and the crack source size during ceramic fracture. AE signals with regard to crack nucleation can be expressed when P{sub 0} is less than 5 and P{sub 3} more than 60; whereas AE signals with regard to dangerous crack propagation can be expressed when more than 92% of P{sub 0} is greater than 4, and more than 95% of P{sub 3} is less than 45. Geiger location algorithm is used to locate AE sources and cracks in the sample. The results of this location algorithm are consistent with the positions of fractures in the sample when observed under a scanning electronic microscope; thus the locations of fractures located with Geiger's method can reflect the fracture process. The stage division by location results is in a good agreement with the division based on AE frequency characteristics. We find that both wavelet package decomposition and Geiger's AE source locations are suitable for the identification of the evolutionary process of cracks in alumina ceramics.« less

X-ray illumination of globular cluster puzzles. [globular cluster X ray sources as clues to Milky Way Galaxy age and evolution

NASA Technical Reports Server (NTRS)

Lightman, A. P.; Grindlay, J. E.

1982-01-01

Globular clusters are thought to be among the oldest objects in the Galaxy, and provide, in this connection, important clues for determining the age and process of formation of the Galaxy. The present investigation is concerned with puzzles relating to the X-ray emission of globular clusters, taking into account questions regarding the location of X-ray emitting clusters (XEGC) unusually near the galactic plane and/or galactic center. An adopted model is discussed for the nature, formation, and lifetime of X-ray sources in globular clusters. An analysis of the available data is conducted in connection with a search for correlations between binary formation time scales, central relaxation times, galactic locations, and X-ray emission. The positive correlation found between distance from galactic center and two-body binary formation time for globular clusters, explanations for this correlation, and the hypothesis that X-ray sources in globular clusters require binary star systems provide a possible explanation of the considered puzzles.

40 CFR 63.6590 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2011 CFR

2011-07-01

... existing, new, or reconstructed stationary RICE located at a major or area source of HAP emissions, excluding stationary RICE being tested at a stationary RICE test cell/stand. (1) Existing stationary RICE. (i) For stationary RICE with a site rating of more than 500 brake horsepower (HP) located at a major...

40 CFR 63.6590 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2010 CFR

2010-07-01

... existing, new, or reconstructed stationary RICE located at a major or area source of HAP emissions, excluding stationary RICE being tested at a stationary RICE test cell/stand. (1) Existing stationary RICE. (i) For stationary RICE with a site rating of more than 500 brake horsepower (HP) located at a major...

Detailed investigation of the gamma-ray emission in the vicinity of SNR W28 with Fermi-LAT

DOE PAGES

Hanabata, Y.; Katagiri, H.; Hewitt, J. W.; ...

2014-04-25

Here, we present a detailed investigation of the γ-ray emission in the vicinity of the supernova remnant (SNR) W28 (G6.4–0.1) observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. We detected significant γ-ray emission spatially coincident with TeV sources HESS J1800–240A, B, and C, located outside the radio boundary of the SNR. Their spectra in the 2-100 GeV band are consistent with the extrapolation of the power-law spectra of the TeV sources. We also identified a new source of GeV emission, dubbed Source W, which lies outside the boundary of TeV sources and coincides withmore » radio emission from the western part of W28. All of the GeV γ-ray sources overlap with molecular clouds in the velocity range from 0 to 20 km s –1. Under the assumption that the γ-ray emission toward HESS J1800–240A, B, and C comes from π 0 decay due to the interaction between the molecular clouds and cosmic rays (CRs) escaping from W28, they can be naturally explained by a single model in which the CR diffusion coefficient is smaller than the theoretical expectation in the interstellar space. Furthermore, we constrain the total energy of the CRs escaping from W28 through the same modeling to be larger than ~2 × 10 49 erg. The emission from Source W can also be explained with the same CR escape scenario.« less

Bootstrap inversion technique for atmospheric trace gas source detection and quantification using long open-path laser measurements

NASA Astrophysics Data System (ADS)

Alden, Caroline B.; Ghosh, Subhomoy; Coburn, Sean; Sweeney, Colm; Karion, Anna; Wright, Robert; Coddington, Ian; Rieker, Gregory B.; Prasad, Kuldeep

2018-03-01

Advances in natural gas extraction technology have led to increased activity in the production and transport sectors in the United States and, as a consequence, an increased need for reliable monitoring of methane leaks to the atmosphere. We present a statistical methodology in combination with an observing system for the detection and attribution of fugitive emissions of methane from distributed potential source location landscapes such as natural gas production sites. We measure long (> 500 m), integrated open-path concentrations of atmospheric methane using a dual frequency comb spectrometer and combine measurements with an atmospheric transport model to infer leak locations and strengths using a novel statistical method, the non-zero minimum bootstrap (NZMB). The new statistical method allows us to determine whether the empirical distribution of possible source strengths for a given location excludes zero. Using this information, we identify leaking source locations (i.e., natural gas wells) through rejection of the null hypothesis that the source is not leaking. The method is tested with a series of synthetic data inversions with varying measurement density and varying levels of model-data mismatch. It is also tested with field observations of (1) a non-leaking source location and (2) a source location where a controlled emission of 3.1 × 10-5 kg s-1 of methane gas is released over a period of several hours. This series of synthetic data tests and outdoor field observations using a controlled methane release demonstrates the viability of the approach for the detection and sizing of very small leaks of methane across large distances (4+ km2 in synthetic tests). The field tests demonstrate the ability to attribute small atmospheric enhancements of 17 ppb to the emitting source location against a background of combined atmospheric (e.g., background methane variability) and measurement uncertainty of 5 ppb (1σ), when measurements are averaged over 2 min. The results of the synthetic and field data testing show that the new observing system and statistical approach greatly decreases the incidence of false alarms (that is, wrongly identifying a well site to be leaking) compared with the same tests that do not use the NZMB approach and therefore offers increased leak detection and sizing capabilities.

Quantifying Volatile Organic Compound Emissions from Solvents and their Impacts on Urban Air Quality

NASA Astrophysics Data System (ADS)

Mcdonald, B. C.; De Gouw, J. A.; Gilman, J.; Ahmadov, R.; Cappa, C. D.; Frost, G. J.; Goldstein, A. H.; Jathar, S.; Jimenez, J. L.; Kim, S. W.; McKeen, S. A.; Roberts, J. M.; Trainer, M.

2016-12-01

Solvents, which consist of personal care products, paints, degreasing agents, and other chemical products, are an important anthropogenic source of volatile organic compound (VOC) emissions. Yet there are many unresolved questions related to their emission rates, chemical composition, and relative importance on urban air quality problems. Using atmospheric measurements of speciated VOCs collected at a ground site located in the Los Angeles basin during the California Nexus (CalNex) Study in 2010, and utilizing data on the composition of solvent emissions from the California Air Resources Board (CARB), we are able to reconcile solvent emissions with ambient observations. Our analysis indicates that solvent emissions are underestimated by a factor of 2-3 in the CARB inventory. We then estimate the reactivity of solvent emissions with the hydroxyl (OH) radical, and also estimate the propensity of solvent emissions to form secondary organic aerosol (SOA). Solvents contain significant fractions of oxygenated compounds, including intermediate volatility compounds, which if released to the atmosphere are potentially reactive and can lead to the formation of SOA. Overall, our results suggest that in the Los Angeles basin, solvents are now the largest anthropogenic source of VOC emissions, OH reactivity, and SOA formation, and larger than the contribution from motor vehicles. This suggests that more research is needed in better constraining this potentially important source of urban VOC emissions.

A New Global Open Source Marine Hydrocarbon Emission Site Database

NASA Astrophysics Data System (ADS)

Onyia, E., Jr.; Wood, W. T.; Barnard, A.; Dada, T.; Qazzaz, M.; Lee, T. R.; Herrera, E.; Sager, W.

2017-12-01

Hydrocarbon emission sites (e.g. seeps) discharge large volumes of fluids and gases into the oceans that are not only important for biogeochemical budgets, but also support abundant chemosynthetic communities. Documenting the locations of modern emissions is a first step towards understanding and monitoring how they affect the global state of the seafloor and oceans. Currently, no global open source (i.e. non-proprietry) detailed maps of emissions sites are available. As a solution, we have created a database that is housed within an Excel spreadsheet and use the latest versions of Earthpoint and Google Earth for position coordinate conversions and data mapping, respectively. To date, approximately 1,000 data points have been collected from referenceable sources across the globe, and we are continualy expanding the dataset. Due to the variety of spatial extents encountered, to identify each site we used two different methods: 1) point (x, y, z) locations for individual sites and; 2) delineation of areas where sites are clustered. Certain well-known areas, such as the Gulf of Mexico and the Mediterranean Sea, have a greater abundance of information; whereas significantly less information is available in other regions due to the absence of emission sites, lack of data, or because the existing data is proprietary. Although the geographical extent of the data is currently restricted to regions where the most data is publicly available, as the database matures, we expect to have more complete coverage of the world's oceans. This database is an information resource that consolidates and organizes the existing literature on hydrocarbons released into the marine environment, thereby providing a comprehensive reference for future work. We expect that the availability of seafloor hydrocarbon emission maps will benefit scientific understanding of hydrocarbon rich areas as well as potentially aiding hydrocarbon exploration and environmental impact assessements.

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.

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.

Volcanoes as emission sources of atmospheric mercury in the Mediterranean basin

PubMed

Ferrara; Mazzolai; Lanzillotta; Nucaro; Pirrone

2000-10-02

Emissions from volcanoes, fumaroles and solfataras as well as contributions from widespread geological anomalies could represent an important source of mercury released to the atmosphere in the Mediterranean basin. Volcanoes located in this area (Etna, Stromboli and Vulcano) are the most active in Europe; therefore, it is extremely important to know their mercury contributions to the regional atmospheric budget. Two main methods are used for the evaluation of volcanic mercury flux: a direct determination of the flux (by measuring in the plume) and an indirect one derived from the determination of the Hg/SO2 (or Hg/S) ratio value, as SO2 emissions are constantly monitored by volcanologists. An attempt to estimate mercury flux from the Vulcano volcano and to establish the Hg/S ratio value has been made along three field campaigns carried out in October 1998, in February and May 1999 sampling several fumaroles. Traditional sampling methods were used to collect both total Hg and S. The average Hg/S ratio value resulted to be 1.2 x 10(-7). From the Hg/S value we derived the Hg/SO2 value, and by assuming that all the volcanoes located in this area have the same Hg/SO2 ratio, mercury emissions from Vulcano and Stromboli were estimated to be in the range 1.3-5.5 kg/year and 7.3-76.6 kg/year respectively, while for Etna mercury flux ranged from 61.8 to 536.5 kg/year. Data reported in literature appear to be overestimated (Fitzgerald WF. Mercury emission from volcanos. In: 4th International conference on mercury as a global pollutant, August 4-8 1996, Hamburg, Germany), volcanic mercury emission does not constitute the main natural source of the metal.

Enhancing weak transient signals in SEVIRI false color imagery: Application to dust source detection in southern Africa

NASA Astrophysics Data System (ADS)

Murray, J. E.; Brindley, H. E.; Bryant, R. G.; Russell, J. E.; Jenkins, K. F.; Washington, R.

2016-09-01

A method is described to significantly enhance the signature of dust events using observations from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI). The approach involves the derivation of a composite clear-sky signal for selected channels on an individual time step and pixel basis. These composite signals are subtracted from each observation in the relevant channels to enhance weak transient signals associated with either (a) low levels of dust emission or (b) dust emissions with high salt or low quartz content. Different channel combinations, of the differenced data from the steps above, are then rendered in false color imagery for the purpose of improved identification of dust source locations and activity. We have applied this clear-sky difference (CSD) algorithm over three (globally significant) source regions in southern Africa: the Makgadikgadi Basin, Etosha Pan, and the Namibian and western South African coast. Case study analyses indicate three notable advantages associated with the CSD approach over established image rendering methods: (i) an improved ability to detect dust plumes, (ii) the observation of source activation earlier in the diurnal cycle, and (iii) an improved ability to resolve and pinpoint dust plume source locations.

Influence of different emission sources on atmospheric organochlorine patterns in Germany

NASA Astrophysics Data System (ADS)

Wenzel, Klaus-Dieter; Hubert, Andreas; Weissflog, Ludwig; Kühne, Ralph; Popp, Peter; Kindler, Annegret; Schüürmann, Gerrit

The concentrations of organochlorine parent substances such as p,p'-DDT (2,2-bis(chlorophenyl)-1,1,1-trichloroethane) and lindane ( γ-hexachlorocyclohexane (HCH)) as well as of their metabolites and conversion products, chlorobenzenes (CBz) and polychlorinated biphenyl congeners (PCBs), were determined both in the gas phase and in the particle bound fraction at 10 locations in Germany. The ratios between parent substances and possible degradation products were influenced by different gaseous point-source emissions. Factors of site-related degradation products are dependent on the emission source. Surprisingly, the highest degradation ratios of p,p'-DDT to DDE and DDD were not calculated at +20 °C, but at -19 °C. This indicates that heavy metals, black carbon and other organic substances such as PAHs may catalyse degradation reactions on particles because of higher condensation of all these substances at lower temperatures. To detect hidden characteristic of pollutant patterns that are dependent on the specific emission source and on typical degradation processes, the principal component analysis (PCA) results suggested that the organochlorines appear to be associated. Comparatively higher concentrations of DDX and HCH isomers mean at some sites also higher concentrations of CBz and PCBs, without an additional source being recognizable.

Airborne remote sensing and in situ measurements of atmospheric CO2 to quantify point source emissions

NASA Astrophysics Data System (ADS)

Krings, Thomas; Neininger, Bruno; Gerilowski, Konstantin; Krautwurst, Sven; Buchwitz, Michael; Burrows, John P.; Lindemann, Carsten; Ruhtz, Thomas; Schüttemeyer, Dirk; Bovensmann, Heinrich

2018-02-01

Reliable techniques to infer greenhouse gas emission rates from localised sources require accurate measurement and inversion approaches. In this study airborne remote sensing observations of CO2 by the MAMAP instrument and airborne in situ measurements are used to infer emission estimates of carbon dioxide released from a cluster of coal-fired power plants. The study area is complex due to sources being located in close proximity and overlapping associated carbon dioxide plumes. For the analysis of in situ data, a mass balance approach is described and applied, whereas for the remote sensing observations an inverse Gaussian plume model is used in addition to a mass balance technique. A comparison between methods shows that results for all methods agree within 10 % or better with uncertainties of 10 to 30 % for cases in which in situ measurements were made for the complete vertical plume extent. The computed emissions for individual power plants are in agreement with results derived from emission factors and energy production data for the time of the overflight.

BTEX exposures in an area impacted by industrial and mobile sources: Source attribution and impact of averaging time.

PubMed

Presto, Albert A; Dallmann, Timothy R; Gu, Peishi; Rao, Unnati

2016-04-01

The impacts of emissions plumes from major industrial sources on black carbon (BC) and BTEX (benzene, toluene, ethyl benzene, xylene isomers) exposures in communities located >10 km from the industrial source areas were identified with a combination of stationary measurements, source identification using positive matrix factorization (PMF), and dispersion modeling. The industrial emissions create multihour plume events of BC and BTEX at the measurement sites. PMF source apportionment, along with wind patterns, indicates that the observed pollutant plumes are the result of transport of industrial emissions under conditions of low boundary layer height. PMF indicates that industrial emissions contribute >50% of outdoor exposures of BC and BTEX species at the receptor sites. Dispersion modeling of BTEX emissions from known industrial sources predicts numerous overnight plumes and overall qualitative agreement with PMF analysis, but predicts industrial impacts at the measurement sites a factor of 10 lower than PMF. Nonetheless, exposures associated with pollutant plumes occur mostly at night, when residents are expected to be home but are perhaps unaware of the elevated exposure. Averaging data samples over long times typical of public health interventions (e.g., weekly or biweekly passive sampling) misapportions the exposure, reducing the impact of industrial plumes at the expense of traffic emissions, because the longer samples cannot resolve subdaily plumes. Suggestions are made for ways for future distributed pollutant mapping or intervention studies to incorporate high time resolution tools to better understand the potential impacts of industrial plumes. Emissions from industrial or other stationary sources can dominate air toxics exposures in communities both near the source and in downwind areas in the form of multihour plume events. Common measurement strategies that use highly aggregated samples, such as weekly or biweekly averages, are insensitive to such plume events and can lead to significant under apportionment of exposures from these sources.

Signature of inverse Compton emission from blazars

NASA Astrophysics Data System (ADS)

Gaur, Haritma; Mohan, Prashanth; Wierzcholska, Alicja; Gu, Minfeng

2018-01-01

Blazars are classified into high-, intermediate- and low-energy-peaked sources based on the location of their synchrotron peak. This lies in infra-red/optical to ultra-violet bands for low- and intermediate-peaked blazars. The transition from synchrotron to inverse Compton emission falls in the X-ray bands for such sources. We present the spectral and timing analysis of 14 low- and intermediate-energy-peaked blazars observed with XMM-Newton spanning 31 epochs. Parametric fits to X-ray spectra help constrain the possible location of transition from the high-energy end of the synchrotron to the low-energy end of the inverse Compton emission. In seven sources in our sample, we infer such a transition and constrain the break energy in the range 0.6-10 keV. The Lomb-Scargle periodogram is used to estimate the power spectral density (PSD) shape. It is well described by a power law in a majority of light curves, the index being flatter compared to general expectation from active galactic nuclei, ranging here between 0.01 and 1.12, possibly due to short observation durations resulting in an absence of long-term trends. A toy model involving synchrotron self-Compton and external Compton (EC; disc, broad line region, torus) mechanisms are used to estimate magnetic field strength ≤0.03-0.88 G in sources displaying the energy break and infer a prominent EC contribution. The time-scale for variability being shorter than synchrotron cooling implies steeper PSD slopes which are inferred in these sources.

Modeling of pesticide emissions from agricultural ecosystems

NASA Astrophysics Data System (ADS)

Li, Rong

2012-04-01

Pesticides are applied to crops and soils to improve agricultural yields, but the use of pesticides has become highly regulated because of concerns about their adverse effects on human health and environment. Estimating pesticide emission rates from soils and crops is a key component for risk assessment for pesticide registration, identification of pesticide sources to the contamination of sensitive ecosystems, and appreciation of transport and fate of pesticides in the environment. Pesticide emission rates involve processes occurring in the soil, in the atmosphere, and on vegetation surfaces and are highly dependent on soil texture, agricultural practices, and meteorology, which vary significantly with location and/or time. To take all these factors into account for simulating pesticide emissions from large agricultural ecosystems, this study coupled a comprehensive meteorological model with a dynamic pesticide emission model. The combined model calculates hourly emission rates from both emission sources: current applications and soil residues resulting from historical use. The coupled modeling system is used to compute a gridded (36 × 36 km) hourly toxaphene emission inventory for North America for the year 2000 using a published U.S. toxaphene residue inventory and a Mexican toxaphene residue inventory developed using its historical application rates and a cropland inventory. To my knowledge, this is the first such hourly toxaphene emission inventory for North America. Results show that modeled emission rates have strong diurnal and seasonal variations at a given location and over the entire domain. The simulated total toxaphene emission from contaminated agricultural soils in North America in 2000 was about 255 t, which compares reasonably well to a published annual estimate. Most emissions occur in spring and summer, with domain-wide emission rates in April, May and, June of 36, 51, and 35 t/month, respectively. The spatial distribution of emissions depends on the distribution of toxaphene soil residues, and high emission rates coincide with heavily contaminated areas.

Detection of very high energy gamma-ray emission from the gravitationally lensed blazar QSO B0218+357 with the MAGIC telescopes

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Arcaro, C.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Buson, S.; Carosi, A.; Chatterjee, A.; Clavero, R.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Toyama, T.; Treves, A.; Vanzo, G.; Verguilov, V.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Zanin, R.; Desiante, R.

2016-11-01

Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components that are spatially indistinguishable by gamma-ray instruments, but separated by a 10-12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. Aims: The spectral energy distribution of QSO B0218+357 can give information on the energetics of z 1 very high energy gamma-ray sources. Moreover the gamma-ray emission can also be used as a probe of the extragalactic background light at z 1. Methods: MAGIC performed observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data obtained by Fermi-LAT and MAGIC are used to set constraints on the extragalactic background light. Results: Very high energy gamma-ray emission was detected from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray source detected to date. The observed emission spans the energy range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broadband emission can be modeled in the framework of a two-zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.

Detection of very high energy gamma-ray emission from the gravitationally lensed blazar QSO B0218+357 with the MAGIC telescopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.

QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components that are spatially indistinguishable by gamma-ray instruments, but separated by a 10–12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. The spectral energy distribution of QSO B0218+357 can give information on the energetics of z ~ 1 very high energy gamma-ray sources. Furthermore, the gamma-ray emission can also be used as a probe of the extragalactic background light at z ~ 1. MAGIC performedmore » observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data obtained by Fermi-LAT and MAGIC are used to set constraints on the extragalactic background light. We detected very high energy gamma-ray emission from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray source detected to date. We also observed emission spans the energy range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broadband emission can be modeled in the framework of a two-zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.« less

Detection of very high energy gamma-ray emission from the gravitationally lensed blazar QSO B0218+357 with the MAGIC telescopes

DOE PAGES

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; ...

2016-11-04

QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components that are spatially indistinguishable by gamma-ray instruments, but separated by a 10–12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. The spectral energy distribution of QSO B0218+357 can give information on the energetics of z ~ 1 very high energy gamma-ray sources. Furthermore, the gamma-ray emission can also be used as a probe of the extragalactic background light at z ~ 1. MAGIC performedmore » observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data obtained by Fermi-LAT and MAGIC are used to set constraints on the extragalactic background light. We detected very high energy gamma-ray emission from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray source detected to date. We also observed emission spans the energy range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broadband emission can be modeled in the framework of a two-zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.« less

Attributing Methane and Carbon Dioxide Emissions from Anthropogenic and Natural Sources Using AVIRIS-NG

NASA Astrophysics Data System (ADS)

Thorpe, A. K.; Frankenberg, C.; Thompson, D. R.; Duren, R. M.; Aubrey, A. D.; Bue, B. D.; Green, R. O.; Gerilowski, K.; Krings, T.; Borchardt, J.; Kort, E. A.; Sweeney, C.; Conley, S. A.; Roberts, D. A.; Dennison, P. E.; Ayasse, A.

2016-12-01

Imaging spectrometers like the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) can map large regions with the high spatial resolution necessary to resolve methane (CH4) and carbon dioxide (CO2) emissions. This capability is aided by real time detection and geolocation of gas plumes, permitting unambiguous identification of individual emission source locations and communication to ground teams for rapid follow up. We present results from AVIRIS-NG flight campaigns in the Four Corners region (Colorado and New Mexico) and the San Joaquin Valley (California). Over three hundred plumes were observed, reflecting emissions from anthropogenic and natural sources. Examples of plumes will be shown for a number of sources, including CH4 from well completions, gas processing plants, tanks, pipeline leaks, natural seeps, and CO2 from power plants. Despite these promising results, an imaging spectrometer built exclusively for quantitative mapping of gas plumes would have improved sensitivity compared to AVIRIS-NG. For example, an instrument providing a 1 nm spectral sampling (2,000-2,400 micron) would permit mapping CH4, CO2, H2O, CO, and N2O from more diffuse sources using both airborne and orbital platforms. The ability to identify emission sources offers the potential to constrain regional greenhouse gas budgets and improve partitioning between anthropogenic and natural emission sources. Because the CH4 lifetime is only about 9 years and CH4 has a Global Warming Potential 86 times that of CO2 for a 20 year time interval, mitigating these emissions is a particularly cost-effective approach to reduce overall atmospheric radiative forcing. Fig. 1. True color image subset with superimposed gas plumes showing concentrations in ppmm. Left: AVIRIS-NG observed CH4 plumes from natural gas processing plant extending over 500 m downwind of multiple emissions sources. Right: Multiple CO2 plumes observed from coal-fired power plant.

Analysis of land surface and synoptic conditions during dust storm events in the Middle East via a new high resolution inventory of mineral dust derived from SEVIRI.

NASA Astrophysics Data System (ADS)

Hennen, Mark

2017-04-01

This paper provides the most up-to-date dust climatology for the Middle East, presenting a new high resolution inventory of over 27,000 dust emission events observed over the Middle East in 2006 - 2013. The inventory was derived from the dust RGB product of the Spinning Enhanced Visual and InfraRed Imager (SEVIRI) on-board Meteosat's second generation satellite (MSG). Mineral dust emissions were derived from visual inspection of the SEVIRI scenes which have 4-5 km2 spatial and 15-minute temporal resolution. The location of every emission event was recorded in a database, along with time and trajectory of dust movement. This is an improvement on previous studies, which derive dust source areas from the daily observations of Aerosol Optical Depth whose maxima do not necessarily coincide with sources of emissions and produces more accurate information on the location of the key dust sources in the region. Results showed that dust sources are constrained to relatively small areas, with 21% of dust emission generated from just 0.9% of total surface area of the Middle East, mainly from eight source regions including the Tigris-Euphrates flood plains of Iraq and Syria, Western and Northern Saudi Arabia and the Sistan Basin in Eastern Iran. The Tigris-Euphrates flood plain was the most active dust region, producing 41% of all dust events with a peak activity in 2009. The southern areas of the Arabian Peninsula recorded very few dust emission observations, in contrast to many previous studies which do not use such high temporal resolution data. The activation and frequency of dust emissions are characterised by strong seasonality developing in response to specific synoptic conditions. To characterise synoptic conditions conducive to the development of dust storms, dust days' emission thresholds, based on number of dust emission events per day / per region and specific to each of the eight main dust emitting regions, were determined. ERA Interim reanalysis data were used to characterise synoptic conditions on the identified dust days. With vegetation cover dictating the ability for surface areas to deflate, Normalised Difference Vegetation Index (NDVI) data was acquired from the Moderate Resolution Imaging Spectrodiometer (MODIS) (MOD13A2) 1km database and correlated with dust emission frequency data in the region of greatest dust activity, the Tigris and Euphrates flood plain in Iraq and Syria.

Source identification of individual soot agglomerates in Arctic air by transmission electron microscopy

NASA Astrophysics Data System (ADS)

Weinbruch, S.; Benker, N.; Kandler, K.; Schütze, K.; Kling, K.; Berlinger, B.; Thomassen, Y.; Drotikova, T.; Kallenborn, R.

2018-01-01

Individual soot agglomerates collected at four different locations on the Arctic archipelago Svalbard (Norway) were characterised by transmission electron microscopy and energy-dispersive X-ray microanalysis. For source identification of the ambient soot agglomerates, samples from different local sources (coal burning power plants in Longyearbyen and Barentsburg, diesel and oil burning for power generation in Sveagruva and Ny Ålesund, cruise ship) as well as from other sources which may contribute to Arctic soot concentrations (biomass burning, aircraft emissions, diesel engines) were investigated. Diameter and graphene sheet separation distance of soot primary particles were found to be highly variable within each source and are not suited for source identification. In contrast, concentrations of the minor elements Si, P, K, Ca and Fe showed significant differences which can be used for source attribution. The presence/absence of externally mixed particle groups (fly ashes, tar balls, mercury particles) gives additional hints about the soot sources. Biomass/wood burning, ship emissions and coal burning in Barentsburg can be excluded as major source for ambient soot at Svalbard. The coal power plant in Longyearbyen is most likely a major source of soot in the settlement of Longyearbyen but does not contribute significantly to soot collected at the Global Atmosphere Watch station Zeppelin Mountain near Ny Ålesund. The most probable soot sources at Svalbard are aircraft emissions and diesel exhaust as well as long range transport of coal burning emissions.

Leak localization and quantification with a small unmanned aerial system

NASA Astrophysics Data System (ADS)

Golston, L.; Zondlo, M. A.; Frish, M. B.; Aubut, N. F.; Yang, S.; Talbot, R. W.

2017-12-01

Methane emissions from oil and gas facilities are a recognized source of greenhouse gas emissions, requiring cost-effective and reliable monitoring systems to support leak detection and repair programs. We describe a set of methods for locating and quantifying natural gas leaks using a small unmanned aerial system (sUAS) equipped with a path-integrated methane sensor along with ground-based wind measurements. The algorithms are developed as part of a system for continuous well pad scale (100 m2 area) monitoring, supported by a series of over 200 methane release trials covering multiple release locations and flow rates. Test measurements include data obtained on a rotating boom platform as well as flight tests on a sUAS. The system is found throughout the trials to reliably distinguish between cases with and without a methane release down to 6 scfh (0.032 g/s). Among several methods evaluated for horizontal localization, the location corresponding to the maximum integrated methane reading have performed best with a median error of ± 1 m if two or more flights are averaged, or ± 1.2 m for individual flights. Additionally, a method of rotating the data around the estimated leak location is developed, with the leak magnitude calculated as the average crosswind integrated flux in the region near the source location. Validation of these methods will be presented, including blind test results. Sources of error, including GPS uncertainty, meteorological variables, and flight pattern coverage, will be discussed.

Local and regional factors affecting atmospheric mercury speciation at a remote location

USGS Publications Warehouse

Manolopoulos, H.; Schauer, J.J.; Purcell, M.D.; Rudolph, T.M.; Olson, M.L.; Rodger, B.; Krabbenhoft, D.P.

2007-01-01

Atmospheric concentrations of elemental (Hg0), reactive gaseous (RGM), and particulate (PHg) mercury were measured at two remote sites in the midwestern United States. Concurrent measurements of Hg0, PHg, and RGM obtained at Devil's Lake and Mt. Horeb, located approximately 65 km apart, showed that Hg0 and PHg concentrations were affected by regional, as well as local sources, while RGM was mainly impacted by local sources. Plumes reaching the Devil's Lake site from a nearby coal-fired power plant significantly impacted SO2 and RGM concentrations at Devil's Lake, but had little impact on Hg0. Our findings suggest that traditional modeling approaches to assess sources of mercury deposited that utilize source emissions and large-scale grids may not be sufficient to predict mercury deposition at sensitive locations due to the importance of small-scale sources and processes. We suggest the use of a receptor-based monitoring to better understand mercury source-receptor relationships. ?? 2007 NRC Canada.

Multiband counterparts of two eclipsing ultraluminous X-ray sources in M 51

NASA Astrophysics Data System (ADS)

Urquhart, R.; Soria, R.; Johnston, H. M.; Pakull, M. W.; Motch, C.; Schwope, A.; Miller-Jones, J. C. A.; Anderson, G. E.

2018-04-01

We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images, we found an elongated, 100-pc-long emission-line structure associated with one X-ray source (CXOM51 J132940.0+471237; ULX-1 for simplicity), and a more circular, ionized nebula at the location of the second source (CXOM51 J132939.5+471244; ULX-2 for simplicity). We observed both nebulae with the Large Binocular Telescope's Multi-Object Double Spectrograph. From our analysis of the optical spectra, we argue that the gas in the ULX-1 bubble is shock-ionized, consistent with the effect of a jet with a kinetic power of ≈2 × 1039 erg s-1. Additional X-ray photoionization may also be present, to explain the strength of high-ionization lines such as He II λ4686 and [Ne V] λ3426. On the other hand, the emission lines from the ULX-2 bubble are typical for photoionization by normal O stars suggesting that the nebula is actually an H II region not physically related to the ULX but is simply a chance alignment. From archival Very Large Array data, we also detect spatially extended, steep-spectrum radio emission at the location of the ULX-1 bubble (consistent with its jet origin), but no radio counterpart for ULX-2 (consistent with the lack of shock-ionized gas around that source).

Development of a stationary carbon emission inventory for Shanghai using pollution source census data

NASA Astrophysics Data System (ADS)

Li, Xianzhe; Jiang, Ping; Zhang, Yan; Ma, Weichun

2016-12-01

This study utilizes 521,631 activity data points from the 2007 Shanghai Pollution Source Census to compile a stationary carbon emission inventory for Shanghai. The inventory generated from our dataset shows that a large portion of Shanghai's total energy use consists of coal-oriented energy consumption. The electricity and heat production industries, iron and steel mills, and the petroleum refining industry are the main carbon emitters. In addition, most of these industries are located in Baoshan District, which is Shanghai's largest contributor of carbon emissions. Policy makers can use the enterpriselevel carbon emission inventory and the method designed in this study to construct sound carbon emission reduction policies. The carbon trading scheme to be established in Shanghai based on the developed carbon inventory is also introduced in this paper with the aim of promoting the monitoring, reporting and verification of carbon trading. Moreover, we believe that it might be useful to consider the participation of industries, such as those for food processing, beverage, and tobacco, in Shanghai's carbon trading scheme. Based on the results contained herein, we recommend establishing a comprehensive carbon emission inventory by inputting data from the pollution source census used in this study.

User's guide: Minerals management service outer continental shelf activity database (moad). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steiner, C.K.; Causley, M.C.; Yocke, M.A.

1994-04-01

The 1990 Clean Air Act Amendments require the Minerals Management Service (MMS) to conduct a research study to assess the potential onshore air quality impact from the development of outer continental shelf (OCS) petroleum resources in the Gulf of Mexico. The need for this study arises from concern about the cumulative impacts of current and future OCS emissions on ozone concentrations on nonattainment areas, particularly in Texas and Louisiana. To make quantitative assessments of these impacts, MMS has commissioned an air quality study which includes as a major component the development of a comprehensive emission inventory for photochemical grid modeling.more » The emission inventories prepared in this study include both onshore and offshore emissions. All relevant emissions from anthropogenic and biogenic sources are considered, with special attention focused on offshore anthropogenic sources, including OCS oil and gas production facilities, crew and supply vessels and helicopters serving OCS facilities, commercial shipping and fishing, recreational boating, intercoastal barge traffic and other sources located in the adjacent state waters. This document describes the database created during this study that contains the activity information collected for the development of the OCS platform, and crew/supply vessel and helicopter emission inventories.« less

Spatiotemporal Modelling of Dust Storm Sources Emission in West Asia

NASA Astrophysics Data System (ADS)

Khodabandehloo, E.; Alimohamdadi, A.; Sadeghi-Niaraki, A.; Darvishi Boloorani, A.; Alesheikh, A. A.

2013-09-01

Dust aerosol is the largest contributor to aerosol mass concentrations in the troposphere and has considerable effects on the air quality of spatial and temporal scales. Arid and semi-arid areas of the West Asia are one of the most important regional dust sources in the world. These phenomena directly or indirectly affecting almost all aspects life in almost 15 countries in the region. So an accurate estimate of dust emissions is very crucial for making a common understanding and knowledge of the problem. Because of the spatial and temporal limits of the ground-based observations, remote sensing methods have been found to be more efficient and useful for studying the West Asia dust source. The vegetation cover limits dust emission by decelerating the surface wind velocities and therefore reducing the momentum transport. While all models explicitly take into account the change of wind speed and soil moisture in calculating dust emissions, they commonly employ a "climatological" land cover data for identifying dust source locations and neglect the time variation of surface bareness. In order to compile the aforementioned model, land surface features such as soil moisture, texture, type, and vegetation and also wind speed as atmospheric parameter are used. Having used NDVI data show significant change in dust emission, The modeled dust emission with static source function in June 2008 is 17.02 % higher than static source function and similar result for Mach 2007 show the static source function is 8.91 % higher than static source function. we witness a significant improvement in accuracy of dust forecasts during the months of most soil vegetation changes (spring and winter) compared to outputs resulted from static model, in which NDVI data are neglected.

Methane Emissions in the London Region: Deciphering Regional Sources with Mobile Measurements

NASA Astrophysics Data System (ADS)

Zazzeri, G.; Lowry, D.; Fisher, R. E.; France, J. L.; Lanoisellé, M.; Bjorkegren, A.; Nisbet, E. G.

2014-12-01

Methane stable isotope analysis, coupled with mole fraction measurement, has been used to link isotopic signature to methane emissions from the leading methane sources in the London region, such as landfills and gas leaks. A mobile Picarro G2301 CRDS analyser was installed in a vehicle, together with an anemometer and a Hemisphere GPS receiver, to measure atmospheric methane mole fractions and their relative location. When methane plumes were located and intercepted, air samples were collected in Tedlar bags, for δ13C-CH4 isotopic analysis by CF-GC-IRMS (Continous Flow-Gas Chromatography-Isotopic Ratio Mass Spectroscopy). This method provides high precision isotopic values, determining δ13C-CH4 to ±0.05 per mil. The bulk signature of the methane plume into the atmosphere from the whole source area was obtained by Keeling plot analysis, and a δ13C-CH4 signature, with the relative uncertainty, allocated to each methane source investigated. The averaged δ13C-CH4 signature for landfill sites around the London region is - 58 ± 3 ‰, whereas the δ13C-CH4 signature for gas leaks is fairly constant at -36 ± 2 ‰, a value characteristic of North Sea supply. The Picarro G2301 analyser was installed also on the roof of King's College London, located in the centre of the city, and connected to an air inlet located 7 meters above roof height. An auto-sampler was connected to the same air inlet and launched remotely when a high nocturnal build up was expected, allowing up to twenty air bags to be collected for methane isotopic analysis over a 24 hour period. The main source contributing to overnight methane build up in central London is fugitive gas, in agreement with inventories. From the isotopic characterisation of urban methane sources and the source mix in London, the contribution to the urban methane budget and the local distribution of the methane sources given in inventories can be validated.

National Air Toxics Assessment

EPA Pesticide Factsheets

NATA is an ongoing comprehensive evaluation of air toxics in the U.S. As a screening tool, it helps air agencies prioritize pollutants, emission sources and locations of interest for further study to gain a better understanding of risks.

Climate Forcing by Particles from Specific Sources, With Implications for No-regrets Scenarios

NASA Astrophysics Data System (ADS)

Bond, T. C.; Roden, C. A.; Subramanian, R.; Rasch, P. J.

2006-12-01

Mitigation-- the act of reducing human effects on climate and atmosphere by changing practices-- occurs one source at a time, one country at a time. Examining climate forcing produced by individual sources could be instructive. Two sectors contribute the largest fraction of black carbon aerosols from energy-related combustion: diesel engines and residential biofuel. We examine direct climate forcing by aerosols from these sources in four locations. Because source characterization is lacking, global emission inventories that include chemical composition of particles have often relied on expert judgment. We are gaining information on emission rates and climate- relevant properties through partnerships with projects related to air quality and health in Thailand and Honduras. Despite the presence of organic carbon, black carbon's constant companion, particles from both diesel and biofuel exert net climate warming. In particular, solid-fuel combustion produces material with weak light absorption and strong absorption spectral dependence. We discuss the expected emissions and properties of this material. Revised emission rates and properties are implemented in the Community Atmosphere Model, housed at the National Center for Atmospheric Research, and we tag particles emitted from individual sources. Which sources feed high-forcing regions, such as the area above the low-cloud deck in the North Pacific? Which particles might have been scavenged, and how does uncertainty in removal rates affect single-source forcing? Using model experiments, we estimate central values and uncertainties of direct radiative forcing from each source. Finally, we discuss the potential for reducing climate forcing by mitigating these individual sources. What is the range of benefits expected by addressing these sources, and what are the costs and obstacles? Only by representing uncertainty can we determine the likelihood that reducing these emissions represents a "no- regret" scenario for climate.

Comparison of two trajectory based models for locating particle sources for two rural New York sites

NASA Astrophysics Data System (ADS)

Zhou, Liming; Hopke, Philip K.; Liu, Wei

Two back trajectory-based statistical models, simplified quantitative transport bias analysis and residence-time weighted concentrations (RTWC) have been compared for their capabilities of identifying likely locations of source emissions contributing to observed particle concentrations at Potsdam and Stockton, New York. Quantitative transport bias analysis (QTBA) attempts to take into account the distribution of concentrations around the directions of the back trajectories. In full QTBA approach, deposition processes (wet and dry) are also considered. Simplified QTBA omits the consideration of deposition. It is best used with multiple site data. Similarly the RTWC approach uses concentrations measured at different sites along with the back trajectories to distribute the concentration contributions across the spatial domain of the trajectories. In this study, these models are used in combination with the source contribution values obtained by the previous positive matrix factorization analysis of particle composition data from Potsdam and Stockton. The six common sources for the two sites, sulfate, soil, zinc smelter, nitrate, wood smoke and copper smelter were analyzed. The results of the two methods are consistent and locate large and clearly defined sources well. RTWC approach can find more minor sources but may also give unrealistic estimations of the source locations.

Black Carbon and Sulfate Aerosols in the Arctic: Long-term Trends, Radiative Impacts, and Source Attributions

NASA Astrophysics Data System (ADS)

Wang, H.; Zhang, R.; Yang, Y.; Smith, S.; Rasch, P. J.

2017-12-01

The Arctic has warmed dramatically in recent decades. As one of the important short-lived climate forcers, aerosols affect the Arctic radiative budget directly by interfering radiation and indirectly by modifying clouds. Light-absorbing particles (e.g., black carbon) in snow/ice can reduce the surface albedo. The direct radiative impact of aerosols on the Arctic climate can be either warming or cooling, depending on their composition and location, which can further alter the poleward heat transport. Anthropogenic emissions, especially, BC and SO2, have changed drastically in low/mid-latitude source regions in the past few decades. Arctic surface observations at some locations show that BC and sulfate aerosols had a decreasing trend in the recent decades. In order to understand the impact of long-term emission changes on aerosols and their radiative effects, we use the Community Earth System Model (CESM) equipped with an explicit BC and sulfur source-tagging technique to quantify the source-receptor relationships and decadal trends of Arctic sulfate and BC and to identify variations in their atmospheric transport pathways from lower latitudes. The simulation was conducted for 36 years (1979-2014) with prescribed sea surface temperatures and sea ice concentrations. To minimize potential biases in modeled large-scale circulations, wind fields in the simulation are nudged toward an atmospheric reanalysis dataset, while atmospheric constituents including water vapor, clouds, and aerosols are allowed to evolve according to the model physics. Both anthropogenic and open fire emissions came from the newly released CMIP6 datasets, which show strong regional trends in BC and SO2 emissions during the simulation time period. Results show that emissions from East Asia and South Asia together have the largest contributions to Arctic sulfate and BC concentrations in the upper troposphere, which have an increasing trend. The strong decrease in emissions from Europe, Russia and North America contributed significantly to the overall decreasing trend in Arctic BC and sulfate, especially, in the lower troposphere. The long-term changes in the spatial distributions of aerosols, their radiative impacts and source attributions, along with implications for the Arctic warming trend, will be discussed.

The missing GeV γ-ray binary: Searching for HESS J0632+057 with Fermi-LAT

DOE PAGES

Caliandro, G. A.; Hill, A. B.; Torres, D. F.; ...

2013-09-25

The very high energy (VHE; >100 GeV) source HESS J0632+057 has been recently confirmed as a γ-ray binary, a subclass of the high-mass X-ray binary population, through the detection of an orbital period of 321 d. We performed a deep search for the emission of HESS J0632+057 in the GeV energy range using data from the Fermi Large Area Telescope (LAT). The analysis was challenging due to the source being located in close proximity to the bright γ-ray pulsar PSR J0633+0632 and lying in a crowded region of the Galactic plane where there is prominent diffuse emission. We formulated amore » Bayesian block algorithm adapted to work with weighted photon counts, in order to define the off-pulse phases of PSR J0633+0632. A detailed spectral-spatial model of a 5° circular region centred on the known location of HESS J0632+057 was generated to accurately model the LAT data. No significant emission from the location of HESS J0632+057 was detected in the 0.1–100 GeV energy range integrating over ~3.5 yr of data, with a 95 per cent flux upper limit of F0.1-100 GeV < 3 × 10 –8 ph cm –2 s –1. A search for emission over different phases of the orbit also yielded no significant detection. A search for source emission on shorter time-scales (days–months) did not yield any significant detections. We also report the results of a search for radio pulsations using the 100-m Green Bank Telescope. No periodic signals or individual dispersed bursts of a likely astronomical origin were detected. We estimated the flux density limit of < 90/40 μJy at 2/9 GHz. Furthermore, the LAT flux upper limits combined with the detection of HESS J0632+057 in the 136–400 TeV energy band by the MAGIC collaboration imply that the VHE spectrum must turn over at energies <136 GeV placing constraints on any theoretical models invoked to explain the γ-ray emission.« less

40 CFR 52.233 - Review of new sources and modifications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... requiring the source to be provided with: (i) Sampling ports of a size, number, and location as the Administrator may require, (ii) Safe access to each port, (iii) Instrumentation to monitor and record emission... more than 1 MBtu/h (250 Mg-cal/h) and burns only distillate oil; or has a heat input of not more than...

40 CFR 52.233 - Review of new sources and modifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... requiring the source to be provided with: (i) Sampling ports of a size, number, and location as the Administrator may require, (ii) Safe access to each port, (iii) Instrumentation to monitor and record emission... more than 1 MBtu/h (250 Mg-cal/h) and burns only distillate oil; or has a heat input of not more than...

Formaldehyde Source Attribution in Houston during TexAQS II and TRAMP

NASA Astrophysics Data System (ADS)

Guven, B.; Olaguer, E. P.

2010-12-01

To determine the relative importance of primary vs secondary formaldehyde in Houston, source apportionment was performed on continuous online measurements of VOCs, formaldehyde (HCHO), CO, SO2, and HONO at one urban and two industrial sites. The results of source apportionment were used in conjunction with the meteorological, emission inventory, emission event, and back trajectory data catalogued in Air Research Information Infrastructure (ARII) to determine the dominant source regions and evaluate the accuracy of reported regular and upset emissions from industrial facilities. The contribution of industrial sources such as flares from petrochemical plants and refineries to total atmospheric formaldehyde concentrations at the urban site is estimated to be 17% compared to 23% for mobile sources, amounting to 40% for the total contribution of primary HCHO sources. The relative contribution of industrial sources to HCHO concentration at the urban site increased to about 66% on some mornings coinciding with the HCHO peak concentrations. Secondary formation of HCHO during the day and night resulted from the reactions of industrial olefins and other VOCs with OH or ozone was a significant contributor to HCHO concentrations at the urban site. An analysis of emission event, back trajectory and ambient concentration data in ARII showed that a large percentage of emission events were associated with trajectories that passed through the two industrial sites when peaks in concentrations were detected at those sites. Some peak HCHO concentrations can also be linked to emission events of other VOCs, while a significant portion remained unexplained by the reported events. It is likely, based on the results from the SHARP campaign and our analysis, that some episodic emission events containing HCHO are unreported to the TCEQ. Overlaid CPF plots for nighttime (green) and daytime (red) HCHO concentrations measured at three sites and the locations of the largest emitting point sources around the sites. Average contributions to formaldehyde concentrations.

Organic compounds in aerosols from selected European sites - Biogenic versus anthropogenic sources

NASA Astrophysics Data System (ADS)

Alves, Célia; Vicente, Ana; Pio, Casimiro; Kiss, Gyula; Hoffer, Andras; Decesari, Stefano; Prevôt, André S. H.; Minguillón, María Cruz; Querol, Xavier; Hillamo, Risto; Spindler, Gerald; Swietlicki, Erik

2012-11-01

Atmospheric aerosol samples from a boreal forest (Hyytiälä, April 2007), a rural site in Hungary (K-puszta, summer 2008), a polluted rural area in Italy (San Pietro Capofiume, Po Valley, April 2008), a moderately polluted rural site in Germany located on a meadow (Melpitz, May 2008), a natural park in Spain (Montseny, March 2009) and two urban background locations (Zurich, December 2008, and Barcelona, February/March 2009) were collected. Aliphatics, polycyclic aromatic hydrocarbons, carbonyls, sterols, n-alkanols, acids, phenolic compounds and anhydrosugars in aerosols were chemically characterised by gas chromatography-mass spectrometry, along with source attribution based on the carbon preference index (CPI), the ratios between the unresolved and the chromatographically resolved aliphatics, the contribution of wax n-alkanes, n-alkanols and n-alkanoic acids from plants, diagnostic ratios of individual target compounds and source-specific markers to organic carbon ratios. In spite of transboundary pollution episodes, Hyytiälä registered the lowest levels among all locations. CPI values close to 1 for the aliphatic fraction of the Montseny aerosol suggest that the anthropogenic input may be associated with the transport of aged air masses from the surrounding industrial/urban areas, which superimpose the locally originated hydrocarbons with biogenic origin. Aliphatic and aromatic hydrocarbons in samples from San Pietro Capofiume reveal that fossil fuel combustion is a major source influencing the diel pattern of concentrations. This source contributed to 25-45% of the ambient organic carbon (OC) at the Po Valley site. Aerosols from the German meadow presented variable contributions from both biogenic and anthropogenic sources. The highest levels of vegetation wax components and biogenic secondary organic aerosol (SOA) products were observed at K-puszta, while anthropogenic SOA compounds predominated in Barcelona. The primary vehicular emissions in the Spanish city accounted for around 25-30% of the OC in aerosols. Besides the traffic input (10% of OC), residential wood burning was found to be another dominant emission source contributing to the atmospheric aerosol (up to 38% of OC) at the Swiss urban location. It was estimated that around 10% of the OC mass in the urban sites originates from cooking emissions. Aerosols from the urban area of Zurich presented a much higher PAH content, and benzo(a)pyrene equivalent concentrations sometimes exceeding the mandatory limit.

Large emissions from floodplain trees close the Amazon methane budget.

PubMed

Pangala, Sunitha R; Enrich-Prast, Alex; Basso, Luana S; Peixoto, Roberta Bittencourt; Bastviken, David; Hornibrook, Edward R C; Gatti, Luciana V; Marotta, Humberto; Calazans, Luana Silva Braucks; Sakuragui, Cassia Mônica; Bastos, Wanderley Rodrigues; Malm, Olaf; Gloor, Emanuel; Miller, John Bharat; Gauci, Vincent

2017-12-14

Wetlands are the largest global source of atmospheric methane (CH 4 ), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH 4 in the tropics, consistently underestimate the atmospheric burden of CH 4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH 4 emissions. Here we report CH 4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH 4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ 13 C) of -66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH 4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a 'top-down' regional estimate of CH 4 emissions of 42.7 ± 5.6 teragrams of CH 4 a year for the Amazon basin, based on regular vertical lower-troposphere CH 4 profiles covering the period 2010-2013. We find close agreement between our 'top-down' and combined 'bottom-up' estimates, indicating that large CH 4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH 4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH 4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH 4 source when trees are combined with other emission sources.

Large emissions from floodplain trees close the Amazon methane budget

NASA Astrophysics Data System (ADS)

Pangala, Sunitha R.; Enrich-Prast, Alex; Basso, Luana S.; Peixoto, Roberta Bittencourt; Bastviken, David; Hornibrook, Edward R. C.; Gatti, Luciana V.; Marotta, Humberto; Calazans, Luana Silva Braucks; Sakuragui, Cassia Mônica; Bastos, Wanderley Rodrigues; Malm, Olaf; Gloor, Emanuel; Miller, John Bharat; Gauci, Vincent

2017-12-01

Wetlands are the largest global source of atmospheric methane (CH4), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of -66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010-2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources.

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

NASA Astrophysics Data System (ADS)

Chakraborty, Jayajit; Green, Donna

2014-04-01

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

Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign.

PubMed

Collier, Sonya; Zhou, Shan; Onasch, Timothy B; Jaffe, Daniel A; Kleinman, Lawrence; Sedlacek, Arthur J; Briggs, Nicole L; Hee, Jonathan; Fortner, Edward; Shilling, John E; Worsnop, Douglas; Yokelson, Robert J; Parworth, Caroline; Ge, Xinlei; Xu, Jianzhong; Butterfield, Zachary; Chand, Duli; Dubey, Manvendra K; Pekour, Mikhail S; Springston, Stephen; Zhang, Qi

2016-08-16

Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (∼2700 m a.s.l.) as well as near their sources using an aircraft. The regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), an index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (∼1 h old) and emissions sampled after atmospheric transport (6-45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. These results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.

The Effects of Nitrogen Deposition, Ambient Ozone, and Climate Change on Forests in the Western U.S.

Treesearch

M. E. Fenn

2006-01-01

Nitrogen (N) deposition in the western United States is most severe near major urban areas or downwind of agricultural regions, particularly in areas where confined animal feeding operations such as dairies or feedlots are located. Nitrogen saturated ecosystems are predominantly found in hotspots located within 60 km of urban or agricultural emissions source areas,...

Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth

NASA Astrophysics Data System (ADS)

Abeysekara, A. U.; Albert, A.; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Avila Rojas, D.; Ayala Solares, H. A.; Barber, A. S.; Bautista-Elivar, N.; Becerril, A.; Belmont-Moreno, E.; BenZvi, S. Y.; Berley, D.; Bernal, A.; Braun, J.; Brisbois, C.; Caballero-Mora, K. S.; Capistrán, T.; Carramiñana, A.; Casanova, S.; Castillo, M.; Cotti, U.; Cotzomi, J.; Coutiño de León, S.; De León, C.; De la Fuente, E.; Dingus, B. L.; DuVernois, M. A.; Díaz-Vélez, J. C.; Ellsworth, R. W.; Engel, K.; Enríquez-Rivera, O.; Fiorino, D. W.; Fraija, N.; García-González, J. A.; Garfias, F.; Gerhardt, M.; González Muñoz, A.; González, M. M.; Goodman, J. A.; Hampel-Arias, Z.; Harding, J. P.; Hernández, S.; Hernández-Almada, A.; Hinton, J.; Hona, B.; Hui, C. M.; Hüntemeyer, P.; Iriarte, A.; Jardin-Blicq, A.; Joshi, V.; Kaufmann, S.; Kieda, D.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; Vargas, H. León; Linnemann, J. T.; Longinotti, A. L.; Luis Raya, G.; Luna-García, R.; López-Coto, R.; Malone, K.; Marinelli, S. S.; Martinez, O.; Martinez-Castellanos, I.; Martínez-Castro, J.; Martínez-Huerta, H.; Matthews, J. A.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Nisa, M. U.; Noriega-Papaqui, R.; Pelayo, R.; Pretz, J.; Pérez-Pérez, E. G.; Ren, Z.; Rho, C. D.; Rivière, C.; Rosa-González, D.; Rosenberg, M.; Ruiz-Velasco, E.; Salazar, H.; Salesa Greus, F.; Sandoval, A.; Schneider, M.; Schoorlemmer, H.; Sinnis, G.; Smith, A. J.; Springer, R. W.; Surajbali, P.; Taboada, I.; Tibolla, O.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Vianello, G.; Weisgarber, T.; Westerhoff, S.; Wisher, I. G.; Wood, J.; Yapici, T.; Yodh, G.; Younk, P. W.; Zepeda, A.; Zhou, H.; Guo, F.; Hahn, J.; Li, H.; Zhang, H.

2017-11-01

The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera–electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera–electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin.

Young Stellar Object Candidates in the Aquila Rift Region

NASA Astrophysics Data System (ADS)

Zhang, Miao-miao; Wang, Hong-chi; Stecklum, B.

2010-10-01

Using the 2m telescope of the Turingia State Observatory at Tauten-berg (TLS), imaging observations in 3 wavebands (H α, R and I) are performed in the 16 fields in the Aquila Rift region. The observed fields cover about 7 square degrees. Excluding the 3 fields with unqualified data, the photometrical analysis is made for the remaining 13 fields, from which point sources are identified, and finally 7 H α emission-line star candidates are identified by color-color diagrams. The 7 candidates are located in five fields. Three of them are located near the Galactic plane, while the galactic latitudes of the rest are greater than 4°. The 2 M ASS counterparts of the point sources are identified, and the properties of the 7 H α emission-line star candidates are further analyzed by using the two-color diagrams. It is found that the near-infrared radiation from these H α emission-line star candidates has no obvious infrared excess, one of them even falls on the main-sequence branch. This indicates that the H α-emissive young stellar objects (YSOs) are not always accompanied with the infrared excess, and that the results of the H α emission line observation and the infrared excess observation are mutually supplemented. If the 7 H α emission-line star candidates are regarded as YSO candidates, then the number of YSOs in the Aquila Rift region is quite small. The further confirmation of these candidates needs subsequent spectral observations.

Development of differential absorption lidar (DIAL) for detection of CO2, CH4 and PM in Alberta

NASA Astrophysics Data System (ADS)

Wojcik, Michael; Crowther, Blake; Lemon, Robert; Valupadas, Prasad; Fu, Long; Leung, Bonnie; Yang, Zheng; Huda, Quamrul; Chambers, Allan

2005-05-01

Rapid expansion of the oil and gas industry in Alberta, including the oil sands, has challenged the Alberta Government to keep pace in its efforts to monitor and mitigate the environmental impacts of development. The limitations of current monitoring systems has pushed the provincial government to seek out advanced sensing technologies such as satellite imagery and laser based sensors. The Space Dynamics Laboratory (SDL) of Utah State University, in cooperation with Alberta Environmental Monitoring, Evaluation and Reporting Agency (AEMERA), has developed North America's first mobile differential absorption lidar (DIAL) system designed specifically for emissions measurement. This instrument is housed inside a 36' trailer which allows for mobility to travel across Alberta to characterize source emissions and to locate fugitive leaks. DIAL is capable of measuring concentrations for carbon dioxide (CO2) and methane (CH4) at ranges of up to 3 km with a spatial resolution of 10 meters. DIAL can map both CO2 and CH4, as well as particulate matter (PM) in a linear fashion; by scanning the laser beam in both azimuth and elevation DIAL can create images of emissions in two dimensions. DIAL imagery may be used to understand and control production practices, characterize source emissions, determine emission factors, locate fugitive leaks, assess plume dispersion, and confirm air dispersion modeling. A system overview of the DIAL instrument and some representative results will be discussed.

Vehicle-based Methane Mapping Helps Find Natural Gas Leaks and Prioritize Leak Repairs

NASA Astrophysics Data System (ADS)

von Fischer, J. C.; Weller, Z.; Roscioli, J. R.; Lamb, B. K.; Ferrara, T.

2017-12-01

Recently, mobile methane sensing platforms have been developed to detect and locate natural gas (NG) leaks in urban distribution systems and to estimate their size. Although this technology has already been used in targeted deployment for prioritization of NG pipeline infrastructure repair and replacement, one open question regarding this technology is how effective the resulting data are for prioritizing infrastructure repair and replacement. To answer this question we explore the accuracy and precision of the natural gas leak location and emission estimates provided by methane sensors placed on Google Street View (GSV) vehicles. We find that the vast majority (75%) of methane emitting sources detected by these mobile platforms are NG leaks and that the location estimates are effective at identifying the general location of leaks. We also show that the emission rate estimates from mobile detection platforms are able to effectively rank NG leaks for prioritizing leak repair. Our findings establish that mobile sensing platforms are an efficient and effective tool for improving the safety and reducing the environmental impacts of low-pressure NG distribution systems by reducing atmospheric methane emissions.

Bayesian inverse modeling and source location of an unintended 131I release in Europe in the fall of 2011

NASA Astrophysics Data System (ADS)

Tichý, Ondřej; Šmídl, Václav; Hofman, Radek; Šindelářová, Kateřina; Hýža, Miroslav; Stohl, Andreas

2017-10-01

In the fall of 2011, iodine-131 (131I) was detected at several radionuclide monitoring stations in central Europe. After investigation, the International Atomic Energy Agency (IAEA) was informed by Hungarian authorities that 131I was released from the Institute of Isotopes Ltd. in Budapest, Hungary. It was reported that a total activity of 342 GBq of 131I was emitted between 8 September and 16 November 2011. In this study, we use the ambient concentration measurements of 131I to determine the location of the release as well as its magnitude and temporal variation. As the location of the release and an estimate of the source strength became eventually known, this accident represents a realistic test case for inversion models. For our source reconstruction, we use no prior knowledge. Instead, we estimate the source location and emission variation using only the available 131I measurements. Subsequently, we use the partial information about the source term available from the Hungarian authorities for validation of our results. For the source determination, we first perform backward runs of atmospheric transport models and obtain source-receptor sensitivity (SRS) matrices for each grid cell of our study domain. We use two dispersion models, FLEXPART and Hysplit, driven with meteorological analysis data from the global forecast system (GFS) and from European Centre for Medium-range Weather Forecasts (ECMWF) weather forecast models. Second, we use a recently developed inverse method, least-squares with adaptive prior covariance (LS-APC), to determine the 131I emissions and their temporal variation from the measurements and computed SRS matrices. For each grid cell of our simulation domain, we evaluate the probability that the release was generated in that cell using Bayesian model selection. The model selection procedure also provides information about the most suitable dispersion model for the source term reconstruction. Third, we select the most probable location of the release with its associated source term and perform a forward model simulation to study the consequences of the iodine release. Results of these procedures are compared with the known release location and reported information about its time variation. We find that our algorithm could successfully locate the actual release site. The estimated release period is also in agreement with the values reported by IAEA and the reported total released activity of 342 GBq is within the 99 % confidence interval of the posterior distribution of our most likely model.

Estimating State-Specific Contributions to PM2.5- and O3-Related Health Burden from Residential Combustion and Electricity Generating Unit Emissions in the United States

PubMed Central

Penn, Stefani L.; Arunachalam, Saravanan; Woody, Matthew; Heiger-Bernays, Wendy; Tripodis, Yorghos; Levy, Jonathan I.

2016-01-01

Background: Residential combustion (RC) and electricity generating unit (EGU) emissions adversely impact air quality and human health by increasing ambient concentrations of fine particulate matter (PM2.5) and ozone (O3). Studies to date have not isolated contributing emissions by state of origin (source-state), which is necessary for policy makers to determine efficient strategies to decrease health impacts. Objectives: In this study, we aimed to estimate health impacts (premature mortalities) attributable to PM2.5 and O3 from RC and EGU emissions by precursor species, source sector, and source-state in the continental United States for 2005. Methods: We used the Community Multiscale Air Quality model employing the decoupled direct method to quantify changes in air quality and epidemiological evidence to determine concentration–response functions to calculate associated health impacts. Results: We estimated 21,000 premature mortalities per year from EGU emissions, driven by sulfur dioxide emissions forming PM2.5. More than half of EGU health impacts are attributable to emissions from eight states with significant coal combustion and large downwind populations. We estimate 10,000 premature mortalities per year from RC emissions, driven by primary PM2.5 emissions. States with large populations and significant residential wood combustion dominate RC health impacts. Annual mortality risk per thousand tons of precursor emissions (health damage functions) varied significantly across source-states for both source sectors and all precursor pollutants. Conclusions: Our findings reinforce the importance of pollutant-specific, location-specific, and source-specific models of health impacts in design of health-risk minimizing emissions control policies. Citation: Penn SL, Arunachalam S, Woody M, Heiger-Bernays W, Tripodis Y, Levy JI. 2017. Estimating state-specific contributions to PM2.5- and O3-related health burden from residential combustion and electricity generating unit emissions in the United States. Environ Health Perspect 125:324–332; http://dx.doi.org/10.1289/EHP550 PMID:27586513

Hard X-ray imaging from Explorer

NASA Technical Reports Server (NTRS)

Grindlay, J. E.; Murray, S. S.

1981-01-01

Coded aperture X-ray detectors were applied to obtain large increases in sensitivity as well as angular resolution. A hard X-ray coded aperture detector concept is described which enables very high sensitivity studies persistent hard X-ray sources and gamma ray bursts. Coded aperture imaging is employed so that approx. 2 min source locations can be derived within a 3 deg field of view. Gamma bursts were located initially to within approx. 2 deg and X-ray/hard X-ray spectra and timing, as well as precise locations, derived for possible burst afterglow emission. It is suggested that hard X-ray imaging should be conducted from an Explorer mission where long exposure times are possible.

Methane Leak Detection and Emissions Quantification with UAVs

NASA Astrophysics Data System (ADS)

Barchyn, T.; Fox, T. A.; Hugenholtz, C.

2016-12-01

Robust leak detection and emissions quantification algorithms are required to accurately monitor greenhouse gas emissions. Unmanned aerial vehicles (UAVs, `drones') could both reduce the cost and increase the accuracy of monitoring programs. However, aspects of the platform create unique challenges. UAVs typically collect large volumes of data that are close to source (due to limited range) and often lower quality (due to weight restrictions on sensors). Here we discuss algorithm development for (i) finding sources of unknown position (`leak detection') and (ii) quantifying emissions from a source of known position. We use data from a simulated leak and field study in Alberta, Canada. First, we detail a method for localizing a leak of unknown spatial location using iterative fits against a forward Gaussian plume model. We explore sources of uncertainty, both inherent to the method and operational. Results suggest this method is primarily constrained by accurate wind direction data, distance downwind from source, and the non-Gaussian shape of close range plumes. Second, we examine sources of uncertainty in quantifying emissions with the mass balance method. Results suggest precision is constrained by flux plane interpolation errors and time offsets between spatially adjacent measurements. Drones can provide data closer to the ground than piloted aircraft, but large portions of the plume are still unquantified. Together, we find that despite larger volumes of data, working with close range plumes as measured with UAVs is inherently difficult. We describe future efforts to mitigate these challenges and work towards more robust benchmarking for application in industrial and regulatory settings.

Fast Identification of Methane and Other Atmospheric Contaminant Sources in Complex Urban Settings

NASA Astrophysics Data System (ADS)

Jacobson, G. A.; Crosson, E.; Tan, S. M.

2012-12-01

The identification and quantification of greenhouse gas emissions (fluxes) from urban centers have become of increasing interest over the last few years. This interest is driven 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). Urban CH4 emissions could contribute 7-15% to the global anthropogenic budget of methane. Although it is known that the per capita carbon footprint of compact cities, such as New York City, Boston, and San Francisco, are smaller than sprawling cities, such as Houston, the strengths of individual sources within these cities are not well known. Such information is of use to policy makers because it can be used to incentivize changes in transportation and land use patterns. The work discussed here will highlight a vehicle-based methodology for characterizing urban emissions that enables extremely fast identification of methane sources in complex urban settings. Measurements were taken while driving at speeds from 20 to 40 miles per hour in stop and go traffic and were able to not only identify methane plumes but in addition, provide information about the location of the sources generating these methane plumes. Results showed that a large number of highly localized methane sources were found in Boston and San Francisco. For example, leaks from natural gas production, transmission and distribution lines were found in both cities. Flux chamber measurements of these leaks indicate that the methane flux ranged from 40 to 300 standard cubic feet of natural gas per day. For reference, the average American home uses approximately 200-300 cubic feet of natural gas per day. These leaks increase cost to natural gas suppliers, add to greenhouse gas concentrations, and in extreme cases pose a safety hazard. In this work, results showing the identification, location, and quantifying methane sources in urban settings will be presented. We will also present how these techniques could be extended for use in further identification of urban emissions, for example, by measuring H2S produced by sewage, landfills or industrial processes. (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.; Mobile methane survey results showing how plume signatures can be used to identify natural gas leaks as a source of methane.

Evaluation of thermal infrared hyperspectral imagery for the detection of onshore methane plumes: Significance for hydrocarbon exploration and monitoring

NASA Astrophysics Data System (ADS)

Scafutto, Rebecca DeĺPapa Moreira; de Souza Filho, Carlos Roberto; Riley, Dean N.; de Oliveira, Wilson Jose

2018-02-01

Methane (CH4) is the main constituent of natural gas. Fugitive CH4 emissions partially stem from geological reservoirs (seepages) and leaks in pipelines and petroleum production plants. Airborne hyperspectral sensors with enough spectral and spatial resolution and high signal-to-noise ratio can potentially detect these emissions. Here, a field experiment performed with controlled release CH4 sources was conducted in the Rocky Mountain Oilfield Testing Center (RMOTC), Casper, WY (USA). These sources were configured to deliver diverse emission types (surface and subsurface) and rates (20-1450 scf/hr), simulating natural (seepages) and anthropogenic (pipeline) CH4 leaks. The Aerospace Corporation's SEBASS (Spatially-Enhanced Broadband Array Spectrograph System) sensor acquired hyperspectral thermal infrared data over the experimental site with 128 bands spanning the 7.6 μm-13.5 μm range. The data was acquired with a spatial resolution of 0.5 m at 1500 ft and 0.84 m at 2500 ft above ground level. Radiance images were pre-processed with an adaptation of the In-Scene Atmospheric Compensation algorithm and converted to emissivity through the Emissivity Normalization algorithm. The data was processed with a Matched Filter. Results allowed the separation between endmembers related to the spectral signature of CH4 from the background. Pixels containing CH4 signatures (absorption bands at 7.69 μm and 7.88 μm) were highlighted and the gas plumes mapped with high definition in the imagery. The dispersion of the mapped plumes is consistent with the wind direction measured independently during the experiment. Variations in the dimension of mapped gas plumes were proportional to the emission rate of each CH4 source. Spectral analysis of the signatures within the plumes shows that CH4 spectral absorption features are sharper and deeper in pixels located near the emitting source, revealing regions with higher gas density and assisting in locating CH4 sources in the field accurately. These results indicate that thermal infrared hyperspectral imaging can support the oil industry profusely, by revealing new petroleum plays through direct detection of gaseous hydrocarbon seepages, serving as tools to monitor leaks along pipelines and oil processing plants, while simultaneously refining estimates of CH4 emissions.

Regional air pollution over Malaysia

NASA Astrophysics Data System (ADS)

Krysztofiak, G.; Catoire, V.; Dorf, M.; Grossmann, K.; Hamer, P. D.; Marécal, V.; Reiter, A.; Schlager, H.; Eckhardt, S.; Jurkat, T.; Oram, D.; Quack, B.; Atlas, E.; Pfeilsticker, K.

2012-12-01

During the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) campaign in Nov. and Dec. 2011 a number of polluted air masses were observed in the marine and terrestrial boundary layer (0 - 2 km) and in the free troposphere (2 - 12 km) over Borneo/Malaysia. The measurements include isoprene, CO, CO2, CH4, N2O, NO2, SO2 as primary pollutants, O3 and HCHO as secondary pollutants, and meteorological parameters. This set of trace gases can be used to fingerprint different sources of local and regional air pollution (e.g., biomass burning and fossil fuel burning, gas flaring on oil rigs, emission of ships and from urban areas, volcanic emissions, and biogenic emissions). Individual sources and location can be identified when the measurements are combined with a nested-grid regional scale chemical and meteorological model and lagrangian particle dispersion model (e.g., CCATT-BRAMS and FLEXPART). In the case of the former, emission inventories of the primary pollutants provide the basis for the trace gas simulations. In this region, the anthropogenic influence on air pollution seems to dominate over natural causes. For example, CO2 and CH4 often show strong correlations with CO, suggesting biomass burning or urban fossil fuel combustion dominates the combustion sources. The study of the CO/CO2 and CH4/CO ratios can help separate anthropogenic combustion from biomass burning pollution sources. In addition, these ratios can be used as a measure of combustion efficiency to help place the type of biomass burning particular to this region within the wider context of fire types found globally. On several occasions, CH4 enhancements are observed near the ocean surface, which are not directly correlated with CO enhancements thus indicating a non-combustion-related CH4 source. Positive correlations between SO2 and CO show the anthropogenic influence of oil rigs located in the South China Sea. Furthermore, SO2 enhancements are observed without any increase in CO, indicating possible volcanic emissions from the Indonesian islands to the South and East and the Philippines to the North East. The regional pollution seems to be influenced by emissions from Singapore, Philippines, Indonesia and Peninsula Malaysia, and on occasion by anthropogenic emissions from Thailand, Vietnam, Australia, and China.

Chemical composition and source apportionment of size fractionated particulate matter in Cleveland, Ohio, USA.

PubMed

Kim, Yong Ho; Krantz, Q Todd; McGee, John; Kovalcik, Kasey D; Duvall, Rachelle M; Willis, Robert D; Kamal, Ali S; Landis, Matthew S; Norris, Gary A; Gilmour, M Ian

2016-11-01

The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM 2.5 ) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible for health effects however are not fully understood. Size-fractionated PM (coarse, fine, and ultrafine) samples were collected using a ChemVol sampler at an urban site (G.T. Craig (GTC)) and rural site (Chippewa Lake (CLM)) from July 2009 to June 2010, and then chemically analyzed. The resulting speciated PM data were apportioned by EPA positive matrix factorization to identify emission sources for each size fraction and location. For comparisons with the ChemVol results, PM samples were also collected with sequential dichotomous and passive samplers, and evaluated for source contributions to each sampling site. The ChemVol results showed that annual average concentrations of PM, elemental carbon, and inorganic elements in the coarse fraction at GTC were ∼2, ∼7, and ∼3 times higher than those at CLM, respectively, while the smaller size fractions at both sites showed similar annual average concentrations. Seasonal variations of secondary aerosols (e.g., high NO 3 - level in winter and high SO 4 2- level in summer) were observed at both sites. Source apportionment results demonstrated that the PM samples at GTC and CLM were enriched with local industrial sources (e.g., steel plant and coal-fired power plant) but their contributions were influenced by meteorological conditions and the emission source's operation conditions. Taken together the year-long PM collection and data analysis provides valuable insights into the characteristics and sources of PM impacting the Cleveland airshed in both the urban center and the rural upwind background locations. These data will be used to classify the PM samples for toxicology studies to determine which PM sources, species, and size fractions are of greatest health concern. Copyright © 2016 Elsevier Ltd. All rights reserved.

Testing a high resolution CO2 and CO emission inventory against atmospheric observations in Salt Lake City, Utah for policy applications

NASA Astrophysics Data System (ADS)

Mendoza, D. L.; Lin, J. C.; Mitchell, L.; Gurney, K. R.; Patarasuk, R.; Mallia, D. V.; Fasoli, B.; Bares, R.; Catharine, D.; O'Keeffe, D.; Song, Y.; Huang, J.; Horel, J.; Crosman, E.; Hoch, S.; Ehleringer, J. R.

2016-12-01

We address the need for robust highly-resolved emissions and trace gas concentration data required for planning purposes and policy development aimed at managing pollutant sources. Adverse health effects resulting from urban pollution exposure are the result of proximity to emission sources and atmospheric mixing, necessitating models with high spatial and temporal resolution. As urban emission sources co-emit carbon dioxide (CO2) and criteria air pollutants (CAPs), efforts to reduce specific pollutants would synergistically reduce others. We present a contemporary (2010-2015) emissions inventory and modeled CO2 and carbon monoxide (CO) concentrations for Salt Lake County, Utah. We compare emissions transported by a dispersion model against stationary measurement data and present a systematic quantification of uncertainties. The emissions inventory for CO2 is based on the Hestia emissions data inventory that resolves emissions at hourly, building and road-link resolutions, as well as on an hourly gridded scale. The emissions were scaled using annual Energy Information Administration (EIA) fuel consumption data. We derived a CO emissions inventory using methods similar to Hestia, downscaling total county emissions from the 2011 Environmental Protection Agency's (EPA) National Emissions Inventory (NEI). The gridded CO emissions were compared against the Hestia CO2 gridded data to characterize spatial similarities and differences between them. Correlations were calculated at multiple scales of aggregation. The Stochastic Time-Inverted Lagrangian Trasport (STILT) dispersion model was used to transport emissions and estimate pollutant concentrations at an hourly resolution. Modeled results were compared against stationary measurements in the Salt Lake County area. This comparison highlights spatial locations and hours of high variability and uncertainty. Sensitivity to biological fluxes as well as to specific economic sectors was tested by varying their contributions to modeled concentrations and calibrating their emissions.

Positive matrix factorization and trajectory modelling for source identification: A new look at Indian Ocean Experiment ship observations

NASA Astrophysics Data System (ADS)

Bhanuprasad, S. G.; Venkataraman, Chandra; Bhushan, Mani

The sources of aerosols on a regional scale over India have only recently received attention in studies using back trajectory analysis and chemical transport modelling. Receptor modelling approaches such as positive matrix factorization (PMF) and the potential source contribution function (PSCF) are effective tools in source identification of urban and regional-scale pollution. In this work, PMF and PSCF analysis is applied to identify categories and locations of sources that influenced surface concentrations of aerosols in the Indian Ocean Experiment (INDOEX) domain measured on-board the research vessel Ron Brown [Quinn, P.K., Coffman, D.J., Bates, T.S., Miller, T.L., Johnson, J.E., Welton, E.J., et al., 2002. Aerosol optical properties during INDOEX 1999: means, variability, and controlling factors. Journal of Geophysical Research 107, 8020, doi:10.1029/2000JD000037]. Emissions inventory information is used to identify sources co-located with probable source regions from PSCF. PMF analysis identified six factors influencing PM concentrations during the INDOEX cruise of the Ron Brown including a biomass combustion factor (35-40%), three industrial emissions factors (35-40%), primarily secondary sulphate-nitrate, balance trace elements and Zn, and two dust factors (20-30%) of Si- and Ca-dust. The identified factors effectively predict the measured submicron PM concentrations (slope of regression line=0.90±0.20; R2=0.76). Probable source regions shifted based on changes in surface and elevated flows during different times in the ship cruise. They were in India in the early part of the cruise, but in west Asia, south-east Asia and Africa, during later parts of the cruise. Co-located sources include coal-fired electric utilities, cement, metals and petroleum production in India and west Asia, biofuel combustion for energy and crop residue burning in India, woodland/forest burning in north sub-Saharan Africa and forest burning in south-east Asia. Significant findings are equivalent contributions of biomass combustion and industrial emissions to the measured aerosol surface concentrations, the origin of carbonaceous aerosols largely from biomass combustion and the identification of probable source regions in Africa, west Asia, the Arabian peninsula and south-east Asia, in addition to India, which affected particulate matter concentrations over parts of the INDOEX domain covered by the Ron Brown cruise.

Using axicons for depth discrimination in excitation-emission laser scanning imaging systems

NASA Astrophysics Data System (ADS)

Iglesias, Ignacio

2017-10-01

Besides generating good approximations to zero-order Bessel beams, an axicon lens coupled to a spatial filter can be used to collect light while preserving information on the depth coordinate of the source location. To demonstrate the principle, we describe an experimental excitation-emission fluorescence imaging system that uses an axicon twice: to generate an excitation Bessel beam and to collect the emitted light.

40 CFR 76.8 - Early election for Group 1, Phase II boilers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.8 Early election for Group 1... plan and: (i) If a Phase I Acid Rain permit governing the source at which the unit is located has been... chapter to include the early election plan; or (ii) If a Phase I Acid Rain permit governing the source at...

40 CFR 76.8 - Early election for Group 1, Phase II boilers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.8 Early election for Group 1... plan and: (i) If a Phase I Acid Rain permit governing the source at which the unit is located has been... chapter to include the early election plan; or (ii) If a Phase I Acid Rain permit governing the source at...

40 CFR 76.8 - Early election for Group 1, Phase II boilers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.8 Early election for Group 1... plan and: (i) If a Phase I Acid Rain permit governing the source at which the unit is located has been... chapter to include the early election plan; or (ii) If a Phase I Acid Rain permit governing the source at...

40 CFR 76.8 - Early election for Group 1, Phase II boilers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.8 Early election for Group 1... plan and: (i) If a Phase I Acid Rain permit governing the source at which the unit is located has been... chapter to include the early election plan; or (ii) If a Phase I Acid Rain permit governing the source at...

40 CFR 76.8 - Early election for Group 1, Phase II boilers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.8 Early election for Group 1... plan and: (i) If a Phase I Acid Rain permit governing the source at which the unit is located has been... chapter to include the early election plan; or (ii) If a Phase I Acid Rain permit governing the source at...

40 CFR 52.780 - Review of new sources and modifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

...,000 Btu per hour (88.2 Mg-cal/h) and 1,500,000 Btu per hour (378.0 MG cal/h), the construction of... requiring the source to be provided with: (i) Sampling ports of a size, number, and location as the Administrator may require, (ii) Safe access to each port, (iii) Instrumentation to monitor and record emission...

40 CFR 52.780 - Review of new sources and modifications.

Code of Federal Regulations, 2011 CFR

2011-07-01

...,000 Btu per hour (88.2 Mg-cal/h) and 1,500,000 Btu per hour (378.0 MG cal/h), the construction of... requiring the source to be provided with: (i) Sampling ports of a size, number, and location as the Administrator may require, (ii) Safe access to each port, (iii) Instrumentation to monitor and record emission...

Integrative health risk assessment of air pollution in the northwest of Spain.

PubMed

García-Santiago, Xela; Gallego-Fernández, Nuria; Muniategui-Lorenzo, Soledad; Piñeiro-Iglesias, María; López-Mahía, Purificación; Franco-Uría, Amaya

2017-02-01

Levels, origins and potential risks due to different air pollutants (ozone, SO 2 and particle-borne metals) in NW Spain were investigated in eight locations affected by different emission sources. All monitored locations suffered the influence of traffic and industrial emissions, being this influence more important in urban locations. Although average values of the estimated hazard index (HI) due to particle-borne metals showed values lower than one, maximum values of this parameter exceeded this safety limit in urban locations. In general, Ni and As were identified as those metals most contributing to the HI. Furthermore, the presence of industrial emission episodes produced a significant increase in the magnitude of the HI in two of the seven urban areas. Therefore, the frequency and intensity of these episodes should be further investigated. Finally, levels of airborne and particle-borne pollutants were integrated with the aim of providing a comprehensive assessment of health risk. According to an established indexing system, air quality can be classified from good to moderate, being the southern urban locations (the most densely populated and industrialised ones) presenting the worst values. However, either the high or the low influence of acute and chronic-effect pollutants on air quality depends on the location.

Response Surface Model (RSM)-based Benefit Per Ton Estimates

EPA Pesticide Factsheets

The tables below are updated versions of the tables appearing in The influence of location, source, and emission type in estimates of the human health benefits of reducing a ton of air pollution (Fann, Fulcher and Hubbell 2009).

Model assessment of atmospheric pollution control schemes for critical emission regions

NASA Astrophysics Data System (ADS)

Zhai, Shixian; An, Xingqin; Liu, Zhao; Sun, Zhaobin; Hou, Qing

2016-01-01

In recent years, the atmospheric environment in portions of China has become significantly degraded and the need for emission controls has become urgent. Because more international events are being planned, it is important to implement air quality assurance targeted at significant events held over specific periods of time. This study sets Yanqihu (YQH), Beijing, the location of the 2014 Beijing APEC (Asia-Pacific Economic Cooperation) summit, as the target region. By using the atmospheric inversion model FLEXPART, we determined the sensitive source zones that had the greatest impact on the air quality of the YQH region in November 2012. We then used the air-quality model Models-3/CMAQ and a high-resolution emissions inventory of the Beijing-Tianjian-Hebei region to establish emission reduction tests for the entire source area and for specific sensitive source zones. This was achieved by initiating emission reduction schemes at different ratios and different times. The results showed that initiating a moderate reduction of emissions days prior to a potential event is more beneficial to the air quality of Beijing than initiating a high-strength reduction campaign on the day of the event. The sensitive source zone of Beijing (BJ-Sens) accounts for 54.2% of the total source area of Beijing (BJ), but its reduction effect reaches 89%-100% of the total area, with a reduction efficiency 1.6-1.9 times greater than that of the entire area. The sensitive source zone of Huabei (HuaB-Sens.) only represents 17.6% of the total area of Huabei (HuaB), but its emission reduction effect reaches 59%-97% of the entire area, with a reduction efficiency 4.2-5.5 times greater than that of the total area. The earlier that emission reduction measures are implemented, the greater the effect they have on preventing the transmission of pollutants. In addition, expanding the controlling areas to sensitive provinces and cities around Beijing (HuaB-sens) can significantly accelerate the reduction effects compared to controlling measures only in the Beijing sensitive source zone (BJ-Sens). Therefore, when enacting emission reduction schemes, cooperating with surrounding provinces and cities, as well as narrowing the reduction scope to specific sensitive source zones prior to unfavorable meteorological conditions, can help reduce emissions control costs and improve the efficiency and maneuverability of emission reduction schemes.

Gaseous and particulate emissions from prescribed burning in Georgia.

PubMed

Lee, Sangil; Baumann, Karsten; Schauer, James J; Sheesley, Rebecca J; Naeher, Luke P; Meinardi, Simone; Blake, Donald R; Edgerton, Eric S; Russell, Armistead G; Clements, Mark

2005-12-01

Prescribed burning is a significant source of fine particulate matter (PM2.5) in the southeastern United States. However, limited data exist on the emission characteristics from this source. Various organic and inorganic compounds both in the gas and particle phase were measured in the emissions of prescribed burnings conducted at two pine-dominated forest areas in Georgia. The measurements of volatile organic compounds (VOCs) and PM2.5 allowed the determination of emission factors for the flaming and smoldering stages of prescribed burnings. The VOC emission factors from smoldering were distinctly higher than those from flaming except for ethene, ethyne, and organic nitrate compounds. VOC emission factors show that emissions of certain aromatic compounds and terpenes such as alpha and beta-pinenes, which are important precursors for secondary organic aerosol (SOA), are much higher from active prescribed burnings than from fireplace wood and laboratory open burning studies. Levoglucosan is the major particulate organic compound (POC) emitted for all these studies, though its emission relative to total organic carbon (mg/g OC) differs significantly. Furthermore, cholesterol, an important fingerprint for meat cooking, was observed only in our in situ study indicating a significant release from the soil and soil organisms during open burning. Source apportionment of ambient primary fine particulate OC measured at two urban receptor locations 20-25 km downwind yields 74 +/- 11% during and immediately after the burns using our new in situ profile. In comparison with the previous source profile from laboratory simulations, however, this OC contribution is on average 27 +/- 5% lower.

Maryland's efforts to develop regulations creating an air emissions offset trading program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guy, D.M.; Zaw-Mon, M.

1999-07-01

Under the federal Clean Air Act's New Source Review program, many companies located in or planning to locate in areas that do not meet federal air quality standards or in the Northeast Ozone Transport Region (northern Virginia to Maine) must obtain emission reductions (called offsets) of volatile organic compounds and nitrogen oxides that are greater than the new emissions that will be released. This offset requirement allows growth in industry while protecting air quality against deterioration. Despite the federal offset requirement, a formal banking and trading program is not mandated by the Clean Air Act Amendments of 1990. Still, amore » mechanism is needed to ensure that emission reduction credits (ERCs) are available for sources to use to meet the offset requirement. Currently, Maryland does not have regulations covering the sale or transfer of ERCs from one facility to another. Maryland works with industry on a case-by-case basis to identify potential sources of ERCs and to assist in obtaining them. Then, the offset requirement and the ERCs used to meet the offsets are incorporated into individual permits using various permitting mechanisms. Desiring certainty and stability in the banking and trading process, Maryland's business community has pressed for regulations to formalize Maryland's procedures. Working over several years through a stakeholder process, Maryland has developed concepts for a trading program and a draft regulation. This paper describes Maryland's current case-by-case banking and trading procedure and traces efforts to develop a regulation to formalize the process. The paper discusses complex policy issues related to establishing a banking and trading program, describes the principal elements of Maryland's draft regulation, and summarizes elements of other states' emissions banking and trading programs.« less

40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a... following operating emission limitations for existing, new and reconstructed 4SRB stationary RICE >500 HP...

Spatial distribution of pollutants in the area of the former CHP plant

NASA Astrophysics Data System (ADS)

Cichowicz, Robert

2018-01-01

The quality of atmospheric air and level of its pollution are now one of the most important issues connected with life on Earth. The frequent nuisance and exceedance of pollution standards often described in the media are generated by both low emission sources and mobile sources. Also local organized energy emission sources such as local boiler houses or CHP plants have impact on air pollution. At the same time it is important to remember that the role of local power stations in shaping air pollution immission fields depends on the height of emitters and functioning of waste gas treatment installations. Analysis of air pollution distribution was carried out in 2 series/dates, i.e. 2 and 10 weeks after closure of the CHP plant. In the analysis as a reference point the largest intersection of streets located in the immediate vicinity of the plant was selected, from which virtual circles were drawn every 50 meters, where 31 measuring points were located. As a result, the impact of carbon dioxide, hydrogen sulfide and ammonia levels could be observed and analyzed, depending on the distance from the street intersection.

The Hestia Project: High Spatial Resolution Fossil Fuel Carbon Dioxide Emissions Quantification at Hourly Scale in Indianapolis, USA

NASA Astrophysics Data System (ADS)

Zhou, Y.; Gurney, K. R.

2009-12-01

In order to advance the scientific understanding of carbon exchange with the land surface and contribute to sound, quantitatively-based U.S. climate change policy interests, quantification of greenhouse gases emissions drivers at fine spatial and temporal scales is essential. Quantification of fossil fuel CO2 emissions, the primary greenhouse gases, has become a key component to cost-effective CO2 emissions mitigation options and a carbon trading system. Called the ‘Hestia Project’, this pilot study generated CO2 emissions down to high spatial resolution and hourly scale for the greater Indianapolis region in the USA through the use of air quality and traffic monitoring data, remote sensing, GIS, and building energy modeling. The CO2 emissions were constructed from three data source categories: area, point, and mobile. For the area source emissions, we developed an energy consumption model using DOE/EIA survey data on building characteristics and energy consumption. With the Vulcan Project’s county-level CO2 emissions and simulated building energy consumption, we quantified the CO2 emissions for each individual building by allocating Vulcan emissions to roughly 50,000 structures in Indianapolis. The temporal pattern of CO2 emissions in each individual building was developed based on temporal patterns of energy consumption. The point sources emissions were derived from the EPA National Emissions Inventory data and effluent monitoring of electricity producing facilities. The mobile source CO2 emissions were estimated at the month/county scale using the Mobile6 combustion model and the National Mobile Inventory Model database. The month/county scale mobile source CO2 emissions were downscaled to the “native” spatial resolution of road segments every hour using a GIS road atlas and traffic monitoring data. The result is shown in Figure 1. The resulting urban-scale inventory can serve as a baseline of current CO2 emissions and should be of immediate use to city environmental managers and regional industry as they plan emission mitigation options and project future emission trends. The results obtained here will also be a useful comparison to atmospheric CO2 monitoring efforts from the top-down. Figure 1. Location of the study area, the building level and mobile CO2 emissions, and an enlarged example neighborhood

DEVELOPMENT OF THE MODEL OF GALACTIC INTERSTELLAR EMISSION FOR STANDARD POINT-SOURCE ANALYSIS OF FERMI LARGE AREA TELESCOPE DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Acero, F.; Ballet, J.; Ackermann, M.

2016-04-01

Most of the celestial γ rays detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point-source and extended-source studies rely on the modeling of this diffuse emission for accurate characterization. Here, we describe the development of the Galactic Interstellar Emission Model (GIEM), which is the standard adopted by the LAT Collaboration and is publicly available. This model is based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse-Compton emission producedmore » in the Galaxy. In the GIEM, we also include large-scale structures like Loop I and the Fermi bubbles. The measured gas emissivity spectra confirm that the cosmic-ray proton density decreases with Galactocentric distance beyond 5 kpc from the Galactic Center. The measurements also suggest a softening of the proton spectrum with Galactocentric distance. We observe that the Fermi bubbles have boundaries with a shape similar to a catenary at latitudes below 20° and we observe an enhanced emission toward their base extending in the north and south Galactic directions and located within ∼4° of the Galactic Center.« less

Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis of Fermi Large Area Telescope Data

NASA Technical Reports Server (NTRS)

Acero, F.; Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Brandt, T. J.;

Aerosol pollution potential from major population centers

NASA Astrophysics Data System (ADS)

Kunkel, D.; Tost, H.; Lawrence, M. G.

2012-09-01

Major population centers (MPCs) or mega-cities represent the largest of growing urban agglomerations with major societal and environmental implications. In terms of air quality they are seen as localized but strong emission sources of aerosols and trace gases which in turn affect air pollution levels in the city or in downwind regions. In the state-of-the-art atmospheric chemistry general circulation model EMAC, generic aerosol and gas phase tracers with equal emission source strengths at 46 MPC locations are used to study the balance between local pollution build up and pollution export, either vertically into the upper troposphere or horizontally, but remaining in the lower atmosphere. The insoluble gas phase tracers with fixed lifetimes are transported with the atmospheric circulation, while the aerosol tracers also undergo gravitational sedimentation as well as dry and wet deposition processes. The strength of low-level tracer export depends on the location of the emission source and prevailing meteorology, in particular on atmospheric stability and the height of the boundary layer and the mixing out of this layer. In contrast, vertical transport of tracer mass depends on the tracer's solubility: the more soluble a tracer is the less mass reaches altitudes above five kilometers. Hence, the mass of insoluble gas phase tracer above five kilometers can be up to ten times higher than the hydrophilic aerosol mass from the same source. In the case of aerosol tracers, pollution build up around the source is determined by meteorological factors which have only indirect effects on tracer lifetime, like surface wind, boundary layer height, and turbulent mixing as well as those which affect the lifetime of the tracers such as precipitation. The longer a tracer stays in the atmosphere, the lower is the relative importance of the location of the source to the atmospheric mass and thus the lower is the relative local pollution build up. We further use aerosol deposition fields to estimate regions with high deposition, that is more than 1% or more than 5% of the corresponding tracer emission deposited in this region. In doing so, we find that the high deposition areas are larger for larger aerosols, and these differ less between the MPCs than for smaller aerosols due to faster deposition. Furthermore, cities in regions with high precipitation rates or unfavorable geographic location, e.g. in a basin, suffer most of this high deposition. Most of the high deposition occurs over land, although about 50% of the MPCs are located along coastlines. By folding the aerosol deposition fields with geographical distributions of cropland, pasture, and forest, the impact on different land ecosystems is assessed. In general, forest are exhibited most to deposition from MPCs while pasture land is least affected. Moreover, the impact on humans, measured with a threshold exceedance of pollutant surface mixing ratios, is more dependent on population densities than on the size of the area holding a certain mixing ratio.

Aerosol pollution potential from major population centers

NASA Astrophysics Data System (ADS)

Kunkel, D.; Tost, H.; Lawrence, M. G.

2013-04-01

Major population centers (MPCs), or megacities, represent the largest of growing urban agglomerations with major societal and environmental implications. In terms of air quality, they are seen as localized but strong emission sources of aerosols and trace gases which in turn affect air pollution levels in the city or in downwind regions. In the state-of-the-art atmospheric chemistry general circulation model EMAC, generic aerosol and gas-phase tracers with equal emission source strengths at 46 MPC locations are used to study the balance between local pollution build-up and pollution export, either vertically into the upper troposphere or horizontally in the lower troposphere. The insoluble gas-phase tracers with fixed lifetimes are transported with the atmospheric circulation, while the aerosol tracers also undergo gravitational sedimentation as well as dry and wet deposition processes. The strength of low-level tracer export depends on the location of the emission source and prevailing meteorology, in particular on atmospheric stability and the height of the boundary layer and the mixing out of this layer. In contrast, vertical transport of tracer mass depends on the tracer's solubility: the more soluble a tracer is, the less mass reaches altitudes above five kilometers. Hence, the mass of insoluble gas-phase tracer above five kilometers can be up to ten times higher than the hydrophilic aerosol mass from the same source. In the case of aerosol tracers, pollution build-up around the source is determined by meteorological factors which have only indirect effects on tracer lifetime, like surface wind, boundary layer height, and turbulent mixing, as well as those which affect the lifetime of the tracers such as precipitation. The longer a tracer stays in the atmosphere, the lower is the relative importance of the location of the source to the atmospheric mass, and thus the lower is the relative local pollution build-up. We further use aerosol deposition fields to estimate regions with high deposition, that is more than 1% or more than 5% of the corresponding tracer emission deposited in this region. In doing so, we find that the high deposition areas are larger for aerosols with diameters of 10.0 μm, and these differ less between the MPCs than for aerosols with diameters smaller than 2.5 μm due to faster deposition. Furthermore, cities in regions with high precipitation rates or unfavorable geographic locations, e.g., in a basin, suffer most of this high deposition. Most of the high deposition occurs over land, although about 50% of the MPCs are located along coastlines. By folding the aerosol deposition fields with geographical distributions of cropland, pasture, and forest, the impact on different land ecosystems is assessed. In general, forest is exposed most to deposition from MPCs while pastureland is least affected. Moreover, the impact on humans, measured with a threshold exceedance of pollutant surface mixing ratios, is more dependent on population densities than on the size of the area with a certain mixing ratio.

Probing the infrared counterparts of diffuse far-ultraviolet sources in the Galaxy

NASA Astrophysics Data System (ADS)

Saikia, Gautam; Shalima, P.; Gogoi, Rupjyoti; Pathak, Amit

2017-12-01

Recent availability of high quality infrared (IR) data for diffuse regions in the Galaxy and external galaxies have added to our understanding of interstellar dust. A comparison of ultraviolet (UV) and IR observations may be used to estimate absorption, scattering and thermal emission from interstellar dust. In this paper, we report IR and UV observations for selective diffuse sources in the Galaxy. Using archival mid-infrared (MIR) and far-infrared (FIR) observations from Spitzer Space Telescope, we look for counterparts of diffuse far-ultraviolet (FUV) sources observed by the Voyager, Far Ultraviolet Spectroscopic Explorer (FUSE) and Galaxy Evolution Explorer (GALEX) telescopes in the Galaxy. IR emission features at 8 μm are generally attributed to Polycyclic Aromatic Hydrocarbon (PAH) molecules, while emission at 24 μm are attributed to Very Small Grains (VSGs). The data presented here is unique and our study tries to establish a relation between various dust populations. By studying the FUV-IR correlations separately at low and high latitude locations, we have identified the grain component responsible for the diffuse FUV emission.

Estimating air emissions from ships: Meta-analysis of modelling approaches and available data sources

NASA Astrophysics Data System (ADS)

Miola, Apollonia; Ciuffo, Biagio

2011-04-01

Maritime transport plays a central role in the transport sector's sustainability debate. Its contribution to air pollution and greenhouse gases is significant. An effective policy strategy to regulate air emissions requires their robust estimation in terms of quantification and location. This paper provides a critical analysis of the ship emission modelling approaches and data sources available, identifying their limits and constraints. It classifies the main methodologies on the basis of the approach followed (bottom-up or top-down) for the evaluation and geographic characterisation of emissions. The analysis highlights the uncertainty of results from the different methods. This is mainly due to the level of uncertainty connected with the sources of information that are used as inputs to the different studies. This paper describes the sources of the information required for these analyses, paying particular attention to AIS data and to the possible problems associated with their use. One way of reducing the overall uncertainty in the results could be the simultaneous use of different sources of information. This paper presents an alternative methodology based on this approach. As a final remark, it can be expected that new approaches to the problem together with more reliable data sources over the coming years could give more impetus to the debate on the global impact of maritime traffic on the environment that, currently, has only reached agreement via the "consensus" estimates provided by IMO (2009).

Upward revision of global fossil fuel methane emissions based on isotope database.

PubMed

Schwietzke, Stefan; Sherwood, Owen A; Bruhwiler, Lori M P; Miller, John B; Etiope, Giuseppe; Dlugokencky, Edward J; Michel, Sylvia Englund; Arling, Victoria A; Vaughn, Bruce H; White, James W C; Tans, Pieter P

2016-10-06

Methane has the second-largest global radiative forcing impact of anthropogenic greenhouse gases after carbon dioxide, but our understanding of the global atmospheric methane budget is incomplete. The global fossil fuel industry (production and usage of natural gas, oil and coal) is thought to contribute 15 to 22 per cent of methane emissions to the total atmospheric methane budget. However, questions remain regarding methane emission trends as a result of fossil fuel industrial activity and the contribution to total methane emissions of sources from the fossil fuel industry and from natural geological seepage, which are often co-located. Here we re-evaluate the global methane budget and the contribution of the fossil fuel industry to methane emissions based on long-term global methane and methane carbon isotope records. We compile the largest isotopic methane source signature database so far, including fossil fuel, microbial and biomass-burning methane emission sources. We find that total fossil fuel methane emissions (fossil fuel industry plus natural geological seepage) are not increasing over time, but are 60 to 110 per cent greater than current estimates owing to large revisions in isotope source signatures. We show that this is consistent with the observed global latitudinal methane gradient. After accounting for natural geological methane seepage, we find that methane emissions from natural gas, oil and coal production and their usage are 20 to 60 per cent greater than inventories. Our findings imply a greater potential for the fossil fuel industry to mitigate anthropogenic climate forcing, but we also find that methane emissions from natural gas as a fraction of production have declined from approximately 8 per cent to approximately 2 per cent over the past three decades.

Methane Emissions from Upland Forests

NASA Astrophysics Data System (ADS)

Megonigal, Patrick; Pitz, Scott; Wang, Zhi-Ping

2016-04-01

Global budgets ascribe 4-10% of atmospheric methane sinks to upland soils and assume that soils are the sole surface for methane exchange between upland forests and the atmosphere. The dogma that upland forests are uniformly atmospheric methane sinks was challenged a decade ago by the discovery of abiotic methane production from plant tissue. Subsequently a variety of relatively cryptic microbial and non-microbial methane sources have been proposed that have the potential to emit methane in upland forests. Despite the accumulating evidence of potential methane sources, there are few data demonstrating actual emissions of methane from a plant surface in an upland forest. We report direct observations of methane emissions from upland tree stems in two temperate forests. Stem methane emissions were observed from several tree species that dominate a forest located on the mid-Atlantic coast of North America (Maryland, USA). Stem emissions occurred throughout the growing season while soils adjacent to the trees simultaneously consumed methane. Scaling fluxes by stem surface area suggested the forest was a net methane source during a wet period in June, and that stem emissions offset 5% of the soil methane sink on an annual basis. High frequency measurements revealed diurnal cycles in stem methane emission rates, pointing to soils as the methane source and transpiration as the most likely pathway for gas transport. Similar observations were made in an upland forest in Beijing, China. However, in this case the evidence suggested the methane was not produced in soils, but in the heartwood by microbial or non-microbial processes. These data challenge the concept that forests are uniform sinks of methane, and suggest that upland forests are smaller methane sinks than previously estimated due to stem emissions. Tree emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration.

A multi-model approach to monitor emissions of CO2 and CO from an urban-industrial complex

NASA Astrophysics Data System (ADS)

Super, Ingrid; Denier van der Gon, Hugo A. C.; van der Molen, Michiel K.; Sterk, Hendrika A. M.; Hensen, Arjan; Peters, Wouter

2017-11-01

Monitoring urban-industrial emissions is often challenging because observations are scarce and regional atmospheric transport models are too coarse to represent the high spatiotemporal variability in the resulting concentrations. In this paper we apply a new combination of an Eulerian model (Weather Research and Forecast, WRF, with chemistry) and a Gaussian plume model (Operational Priority Substances - OPS). The modelled mixing ratios are compared to observed CO2 and CO mole fractions at four sites along a transect from an urban-industrial complex (Rotterdam, the Netherlands) towards rural conditions for October-December 2014. Urban plumes are well-mixed at our semi-urban location, making this location suited for an integrated emission estimate over the whole study area. The signals at our urban measurement site (with average enhancements of 11 ppm CO2 and 40 ppb CO over the baseline) are highly variable due to the presence of distinct source areas dominated by road traffic/residential heating emissions or industrial activities. This causes different emission signatures that are translated into a large variability in observed ΔCO : ΔCO2 ratios, which can be used to identify dominant source types. We find that WRF-Chem is able to represent synoptic variability in CO2 and CO (e.g. the median CO2 mixing ratio is 9.7 ppm, observed, against 8.8 ppm, modelled), but it fails to reproduce the hourly variability of daytime urban plumes at the urban site (R2 up to 0.05). For the urban site, adding a plume model to the model framework is beneficial to adequately represent plume transport especially from stack emissions. The explained variance in hourly, daytime CO2 enhancements from point source emissions increases from 30 % with WRF-Chem to 52 % with WRF-Chem in combination with the most detailed OPS simulation. The simulated variability in ΔCO :  ΔCO2 ratios decreases drastically from 1.5 to 0.6 ppb ppm-1, which agrees better with the observed standard deviation of 0.4 ppb ppm-1. This is partly due to improved wind fields (increase in R2 of 0.10) but also due to improved point source representation (increase in R2 of 0.05) and dilution (increase in R2 of 0.07). Based on our analysis we conclude that a plume model with detailed and accurate dispersion parameters adds substantially to top-down monitoring of greenhouse gas emissions in urban environments with large point source contributions within a ˜ 10 km radius from the observation sites.

Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG

NASA Astrophysics Data System (ADS)

Thorpe, Andrew K.; Frankenberg, Christian; Thompson, David R.; Duren, Riley M.; Aubrey, Andrew D.; Bue, Brian D.; Green, Robert O.; Gerilowski, Konstantin; Krings, Thomas; Borchardt, Jakob; Kort, Eric A.; Sweeney, Colm; Conley, Stephen; Roberts, Dar A.; Dennison, Philip E.

2017-10-01

At local scales, emissions of methane and carbon dioxide are highly uncertain. Localized sources of both trace gases can create strong local gradients in its columnar abundance, which can be discerned using absorption spectroscopy at high spatial resolution. In a previous study, more than 250 methane plumes were observed in the San Juan Basin near Four Corners during April 2015 using the next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) and a linearized matched filter. For the first time, we apply the iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS) method to AVIRIS-NG data and generate gas concentration maps for methane, carbon dioxide, and water vapor plumes. This demonstrates a comprehensive greenhouse gas monitoring capability that targets methane and carbon dioxide, the two dominant anthropogenic climate-forcing agents. Water vapor results indicate the ability of these retrievals to distinguish between methane and water vapor despite spectral interference in the shortwave infrared. We focus on selected cases from anthropogenic and natural sources, including emissions from mine ventilation shafts, a gas processing plant, tank, pipeline leak, and natural seep. In addition, carbon dioxide emissions were mapped from the flue-gas stacks of two coal-fired power plants and a water vapor plume was observed from the combined sources of cooling towers and cooling ponds. Observed plumes were consistent with known and suspected emission sources verified by the true color AVIRIS-NG scenes and higher-resolution Google Earth imagery. Real-time detection and geolocation of methane plumes by AVIRIS-NG provided unambiguous identification of individual emission source locations and communication to a ground team for rapid follow-up. This permitted verification of a number of methane emission sources using a thermal camera, including a tank and buried natural gas pipeline.

Measurement of non-enteric emission fluxes of volatile fatty acids from a California dairy by solid phase micro-extraction with gas chromatography/mass spectrometry

NASA Astrophysics Data System (ADS)

Alanis, Phillip; Sorenson, Mark; Beene, Matt; Krauter, Charles; Shamp, Brian; Hasson, Alam S.

Dairies are a major source of volatile organic compounds (VOCs) in California's San Joaquin Valley; a region that experiences high ozone levels during summer. Short-chain carboxylic acids, or volatile fatty acids (VFAs), are believed to make up a large fraction of VOC emissions from these facilities, although there are few studies to substantiate this. In this work, a method using a flux chamber coupled to solid phase micro-extraction (SPME) fibers followed by analysis using gas chromatography/mass spectrometry was developed to quantify emissions of six VFAs (acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid and 3-methyl butanoic acid) from non-enteric sources. The technique was then used to quantify VFA fluxes from a small dairy located on the campus of California State University Fresno. Both animal feed and animal waste are found to be major sources of VFAs, with acetic acid contributing 70-90% of emissions from the sources tested. Measured total acid fluxes during spring (with an average temperature of 20 °C) were 1.84 ± 0.01, 1.06 ± 0.08, (1.3 ± 0.5) × 10 -2, (1.7 ± 0.2) × 10 -2 and (1.2 ± 0.5) × 10 -2 g m -2 h -1 from silage, total mixed rations, flushing lane, open lot and lagoon sources, respectively. VFA emissions from the sources tested total 390 ± 80 g h -1. The data indicate high fluxes of VFAs from dairy facilities, but differences in the design and operation of dairies in the San Joaquin Valley as well as seasonal variations mean that additional measurements must be made to accurately determine emissions inventories for the region.

EXTENDED X-RAY EMISSION IN THE VICINITY OF THE MICROQUASAR LS 5039: PULSAR WIND NEBULA?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durant, Martin; Kargaltsev, Oleg; Pavlov, George G.

2011-07-01

LS 5039 is a high-mass binary with a period of 4 days, containing a compact object and an O-star, one of the few high-mass binaries detected in {gamma}-rays. Our Chandra Advanced CCD Imaging Spectrometer observation of LS 5039 provided a high-significance ({approx}10{sigma}) detection of extended emission clearly visible for up to 1' from the point source. The spectrum of this emission can be described by an absorbed power-law model with photon index {Gamma} = 1.9 {+-} 0.3, somewhat softer than the point-source spectrum {Gamma} = 1.44 {+-} 0.07, with the same absorption, N{sub H} = (6.4 {+-} 0.6) x 10{supmore » 21} cm{sup -2}. The observed 0.5-8 keV flux of the extended emission is {approx_equal} 8.8 x 10{sup -14} erg s{sup -1}cm{sup -2} or 5% of the point-source flux; the latter is a factor of {approx}2 lower than the lowest flux detected so far. Fainter extended emission with comparable flux and a softer ({Gamma} {approx} 3) spectrum is detected at even greater radii (up to 2'). Two possible interpretations of the extended emission are a dust scattering halo and a synchrotron nebula powered by energetic particles escaping the binary. We discuss both of these scenarios and favor the nebula interpretation, although some dust contribution is possible. We have also found transient sources located within a narrow stripe south of LS 5039. We discuss the likelihood of these sources to be related to LS 5039.« less

The Power Plant Mapping Student Project: Bringing Citizen Science to Schools

NASA Astrophysics Data System (ADS)

Tayne, K.; Oda, T.; Gurney, K. R.; O'Keeffe, D.; Petron, G.; Tans, P. P.; Frost, G. J.

2014-12-01

An emission inventory (EI) is a conventional tool to quantify and monitor anthropogenic emissions of greenhouse gases and air pollutants into the atmosphere. Gridded EI can visually show geographical patterns of emissions and their changes over time. These patterns, when available, are often determined using location data collected by regional governments, industries, and researchers. Datasets such as Carbon Monitoring and Action (CARMA, www.carma.org) are particularly useful for mapping emissions from large point sources and have been widely used in the EI community. The EI community is aware of potentially significant errors in the geographical locations of point sources, including power plants. The big challenge, however, is to review tens of thousands of power plant locations around the world and correct them where needed. The Power Plant Mapping Student Project (PPMSP) is a platform designed for students in 4th through 12th grade to improve the geographical location of power plants indicated in existing datasets to benefit international EI research. In PPMSP, we use VENTUS, a web-based platform (http://ventus.project.asu.edu/) that invites citizens to contribute power plant location data. Using VENTUS, students view scenes in the vicinity of reported power plant coordinates on Google Maps. Students either verify the location of a power plant or search for it within a designated radius using various indicators, an e-guide, and a power plant photo gallery for assistance. If the power plant cannot be found, students mark the plant as unverified. To assure quality for research use, the project contains multiple checkpoints and levels of review. While participating in meaningful research that directly benefits the EI research community, students are engaged in relevant science curricula designed to meet each grade level's Next Generation Science Standards. Students study energy, climate change, the atmosphere, and geographical information systems. The curricula is integrated with math and writing, connecting to the Common Core Standards. PPMSP is designed to be accessible and relevant to all learners, including students learning English. With PPMSP, students are empowered to participate in relevant research and become future leaders in mitigating climate change.

Composition and origin of PM10 in Cape Verde: Characterization of long-range transport episodes

NASA Astrophysics Data System (ADS)

Salvador, P.; Almeida, S. M.; Cardoso, J.; Almeida-Silva, M.; Nunes, T.; Cerqueira, M.; Alves, C.; Reis, M. A.; Chaves, P. C.; Artíñano, B.; Pio, C.

2016-02-01

A receptor modelling study was performed to identify source categories and their contributions to the PM10 total mass at the Cape Verde archipelago. Trajectory statistical methods were also used to characterize the main atmospheric circulation patterns causing the transport of air masses and to geographically identify the main potential source areas of each PM10 source category. Our findings point out that the variability of the PM10 levels at Cape Verde was prompted by the advections of African mineral dust. The mineral dust load was mainly composed by clay-silicates mineral derived elements (22% of the PM10 total mass on average) with lower amounts of carbonates (9%). A clear northward gradient was observed in carbonates concentration that illustrates the differences in the composition according to the source regions of mineral dust. Mineral dust was frequently linked to industrial emissions from crude oil refineries, fertilizer industries as well as oil and coal power plants, located in the northern and north-western coast of the African continent (29%). Sea salt was also registered in the PM10 mass during most part of the sampling period, with a lower impact in the PM10 levels than the mineral dust one (26%). Combustion aerosols (6%) reached the highest mean values in summer as a consequence of the emissions from local-regional sources. Biomass burning aerosols produced from October to November in sub-sahelian latitudes, had a clear influence in the content of elemental carbon (EC) recorded at Cape Verde but a small impact in the PM10 total mass levels. A minor contribution to the PM10 mass has been associated to secondary inorganic compounds-SIC. Namely, ammonium sulfate and nitrate (SIC 1-5%) and calcium sulfate and nitrate (SIC 2-3%). The main origin of SIC 1 was attributed to emissions of SO2 and NOx from industrial sources located in the northern and north-western African coast and from wildfires produced in the continent. SIC 2 had a clear regional origin in the summer period. However, in the winter period there were probably contributions of soil emissions of evaporate minerals from regions of eastern Algeria. The location of Cape Verde in the Atlantic Ocean at subtropical latitudes, and the absence of relevant local sources of anthropogenic atmospheric pollutants, becomes this archipelago, a perfect site to study the impact of external contributions on the background levels of PM10 registered over the north-eastern tropical Atlantic.

Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collier, Sonya; Zhou, Shan; Onasch, Timothy B.

Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (~2700 m a.s.l.) as well as near their sources using an aircraft. In addition, the regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), anmore » index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (~1 h old) and emissions sampled after atmospheric transport (6–45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. In conclusion, these results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.« less

Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign

DOE PAGES

Collier, Sonya; Zhou, Shan; Onasch, Timothy B.; ...

2016-07-11

Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (~2700 m a.s.l.) as well as near their sources using an aircraft. In addition, the regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), anmore » index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (~1 h old) and emissions sampled after atmospheric transport (6–45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. In conclusion, these results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.« less

40 CFR Table 2a to Subpart Zzzz of... - Emission Limitations for New and Reconstructed 2SLB and Compression Ignition Stationary RICE >500...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Reconstructed 2SLB and Compression Ignition Stationary RICE >500 HP and New and Reconstructed 4SLB Stationary RICE â¥250 HP Located at a Major Source of HAP Emissions 2a Table 2a to Subpart ZZZZ of Part 63... 2SLB and Compression Ignition Stationary RICE >500 HP and New and Reconstructed 4SLB Stationary RICE...

40 CFR Table 2a to Subpart Zzzz of... - Emission Limitations for New and Reconstructed 2SLB and Compression Ignition Stationary RICE >500...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Reconstructed 2SLB and Compression Ignition Stationary RICE >500 HP and New and Reconstructed 4SLB Stationary RICE â¥250 HP Located at a Major Source of HAP Emissions 2a Table 2a to Subpart ZZZZ of Part 63... 2SLB and Compression Ignition Stationary RICE >500 HP and New and Reconstructed 4SLB Stationary RICE...

Non-exhaust emissions of PM and the efficiency of emission reduction by road sweeping and washing in the Netherlands.

PubMed

Keuken, Menno; Denier van der Gon, Hugo; van der Valk, Karin

2010-09-15

From research on PM(2.5) and PM(10) in 2007/2008 in the Netherlands, it was concluded that the coarse fraction (PM(2.5-10)) attributed 60% and 50% respectively, to the urban-regional and street-urban increments of PM(10). Contrary to Scandinavian and Mediterranean countries which exhibit significant seasonal variation in the coarse fraction of particulate matter (PM), in the Netherlands the coarse fraction in PM at a street location is rather constant during the year. Non-exhaust emissions by road traffic are identified as the main source for coarse PM in urban areas. Non-exhaust emissions mainly originate from re-suspension of accumulated deposited PM and road wear related particles, while primary tire and brake wear hardly contribute to the mass of non-exhaust emissions. However, tire and brake wear can clearly be identified in the total mass through the presence of the heavy metals: zinc, a tracer for tire wear and copper, a tracer for brake wear. The efficiency of road sweeping and washing to reduce non-exhaust emissions in a street-canyon in Amsterdam was investigated. The increments of the coarse fraction at a kerbside location and a housing façade location versus the urban background were measured at days with and without sweeping and washing. It was concluded that this measure did not significantly reduce non-exhaust emissions. Copyright 2010 Elsevier B.V. All rights reserved.

Locational Determinants of Emissions from Pollution-Intensive Firms in Urban Areas

PubMed Central

Zhou, Min; Tan, Shukui; Guo, Mingjing; Zhang, Lu

2015-01-01

Industrial pollution has remained as one of the most daunting challenges for many regions around the world. Characterizing the determinants of industrial pollution should provide important management implications. Unfortunately, due to the absence of high-quality data, rather few studies have systematically examined the locational determinants using a geographical approach. This paper aimed to fill the gap by accessing the pollution source census dataset, which recorded the quantity of discharged wastes (waste water and solid waste) from 717 pollution-intensive firms within Huzhou City, China. Spatial exploratory analysis was applied to analyze the spatial dependency and local clusters of waste emissions. Results demonstrated that waste emissions presented significantly positive autocorrelation in space. The high-high hotspots generally concentrated towards the city boundary, while the low-low clusters approached the Taihu Lake. Their locational determinants were identified by spatial regression. In particular, firms near the city boundary and county road were prone to discharge more wastes. Lower waste emissions were more likely to be observed from firms with high proximity to freight transfer stations or the Taihu Lake. Dense populous districts saw more likelihood of solid waste emissions. Firms in the neighborhood of rivers exhibited higher waste water emissions. Besides, the control variables (firm size, ownership, operation time and industrial type) also exerted significant influence. The present methodology can be applicable to other areas, and further inform the industrial pollution control practices. Our study advanced the knowledge of determinants of emissions from pollution-intensive firms in urban areas. PMID:25927438

Isotopic signatures of anthropogenic CH4 sources in Alberta, Canada

NASA Astrophysics Data System (ADS)

Lopez, M.; Sherwood, O. A.; Dlugokencky, E. J.; Kessler, R.; Giroux, L.; Worthy, D. E. J.

2017-09-01

A mobile system was used for continuous ambient measurements of stable CH4 isotopes (12CH4 and 13CH4) and ethane (C2H6). This system was used during a winter mobile campaign to investigate the CH4 isotopic signatures and the C2H6/CH4 ratios of the main anthropogenic sources of CH4 in the Canadian province of Alberta. Individual signatures were derived from δ13CH4 and C2H6 measurements in plumes arriving from identifiable single sources. Methane emissions from beef cattle feedlots (n = 2) and landfill (n = 1) had δ13CH4 signatures of -66.7 ± 2.4‰ and -55.3 ± 0.2‰, respectively. The CH4 emissions associated with the oil or gas industry had distinct δ13CH4 signatures, depending on the formation process. Emissions from oil storage tanks (n = 5) had δ13CH4 signatures ranging from -54.9 ± 2.9‰ to -60.6 ± 0.6‰ and non-detectable C2H6, characteristic of secondary microbial methanogenesis in oil-bearing reservoirs. In contrast, CH4 emissions associated with natural gas facilities (n = 8) had δ13CH4 signatures ranging from -41.7 ± 0.7‰ to -49.7 ± 0.7‰ and C2H6/CH4 molar ratios of 0.10 for raw natural gas to 0.04 for processed/refined natural gas, consistent with thermogenic origins. These isotopic signatures and C2H6/CH4 ratios have been used for source discrimination in the weekly atmospheric measurements of stable CH4 isotopes over a two-month winter period at the Lac La Biche (LLB) measurement station, located in Alberta, approximately 200 km northeast of Edmonton. The average signature of -59.5 ± 1.4‰ observed at LLB is likely associated with transport of air after passing over oil industry sources located south of the station.

Characteristics and source apportionment of black carbon aerosols over an urban site.

PubMed

Rajesh, T A; Ramachandran, S

2017-03-01

Aethalometer based source apportionment model using the measured aerosol absorption coefficients at different wavelengths is used to apportion the contribution of fossil fuel and wood burning sources to the total black carbon (BC) mass concentration. Temporal and seasonal variabilities in BC mass concentrations, equivalent BC from fossil fuel (BC f f ), and wood burning (BC w b ) are investigated over an urban location in western India during January 2014 to December 2015. BC, BC f f , and BC w b mass concentrations exhibit strong diurnal variation and are mainly influenced by atmospheric dynamics. BC f f was higher by a factor of 2-4 than BC w b and contributes maximum to BC mass throughout the day, confirming consistent anthropogenic activities. Diurnal contribution of BC f f and BC w b exhibits opposite variation due to differences in emission sources over Ahmedabad. Night time BC values are about a factor of 1.4 higher than day time BC values. The annual mean percentage contributions of day time and night time are 42 and 58 %, respectively. BC, BC f f , and BC w b mass concentrations exhibit large and significant variations during morning, afternoon, evening, and night time. During afternoon, mass concentration values are minimum throughout the year because of the fully evolved boundary layer and reduced anthropogenic activities. BC exhibits a strong seasonal variability with postmonsoon high (8.3 μg m -3 ) and monsoon low (1.9 μg m -3 ). Annual mean BC f f and BC w b contributions are 80 and 20 %, respectively, to total BC, which suggests that major contribution of BC in Ahmedabad comes from fossil fuel emissions. The results show that the study location is dominated by fossil fuel combustion as compared to the emissions from wood burning. The results obtained represent a regional value over an urban regime which can be used as inputs on source apportionment to model BC emissions in regional and global climate models.

What Are “X-shaped” Radio Sources Telling Us? II. Properties of a Sample of 87

NASA Astrophysics Data System (ADS)

Saripalli, Lakshmi; Roberts, David H.

2018-01-01

In an earlier paper, we presented Jansky Very Large Array multi-frequency, multi-array continuum imaging of a unique sample of low-axial ratio radio galaxies. In this paper, the second in the series, we examine the images to learn the phenomenology of how the off-axis emission relates to the main radio source. Inversion-symmetric offset emission appears to be bimodal and to originate from one of two strategic locations: outer ends of radio lobes (outer-deviation) or from inner ends (inner-deviation). The latter sources are almost always associated with edge-brightened sources. With S- and Z-shaped sources being a subset of outer-deviation sources, this class lends itself naturally to explanations involving black hole axis precession. Our data allow us to present a plausible model for the more enigmatic inner-deviation sources with impressive wings; as for outer-deviation sources these too require black hole axis shifts, although they also require plasma backflows into relic channels. Evolution in morphology over time relates the variety in structures in inner-deviation sources including XRGs. With features such as non-collinearities, central inner-S “spine,” corresponding lobe emission peaks, double and protruding hotspots not uncommon, black hole axis precession, drifts, or flips could be active in a significant fraction of radio sources with prominent off-axis emission. At least 4% of radio galaxies appear to undergo black hole axis rotation. Quasars offer a key signature for recognizing rotating axes. With a rich haul of sources that have likely undergone axis rotation, our work shows the usefulness of low-axial ratio sources in pursuing searches for binary supermassive black holes.

Impact of primary and secondary organic sources on the oxidative potential of quasi-ultrafine particles (PM0.25) at three contrasting locations in the Los Angeles Basin

NASA Astrophysics Data System (ADS)

Saffari, Arian; Hasheminassab, Sina; Wang, Dongbin; Shafer, Martin M.; Schauer, James J.; Sioutas, Constantinos

2015-11-01

To investigate the changing contribution of primary and secondary sources on the oxidative potential of particulate matter (PM) in a real-world urban atmosphere, 7 sets of quasi-ultrafine particles (PM0.25) were collected at three contrasting locations in the Los Angeles Basin, California, USA. Samples were collected in the coastal area of Long Beach during the morning rush hour period, representing fresh primary emissions from nearby freeways and the LA port; in central Los Angeles during midday, representing a mixture of fresh primary emissions and early products of photochemical secondary organic aerosol (SOA) formation; and at a downwind site (Upland) during afternoon, when the impacts of photochemically aged secondary PM are significant. Chemical composition showed distinctive trends, with the lowest fraction of water soluble organic carbon (WSOC) and other organic tracers of SOA formation (e.g. organic acids) at Long Beach, and the lowest abundance of organic tracers of primary vehicular emissions (such as polycyclic aromatic hydrocarbons and hopanes) at Upland. A molecular marker-based chemical mass balance (MM-CMB) model indicated that 72% of the total organic carbon at Long Beach was comprised of primary vehicular sources (combined heavy duty and light duty vehicles), while the vehicular fraction was found to be 50% and 39% at Los Angeles and Upland, respectively. Regression analysis suggested that at Long Beach, the variation in oxidative potential of PM0.25 (quantified using a macrophage-based reactive oxygen species (ROS) assay) was mainly driven by mobile vehicular emissions and the water-insoluble fraction of the organic carbon. In contrast, at Upland, where photochemical processing and secondary aerosol formation was the highest, WSOC and secondary organics were the major drivers of the oxidative potential variation. The multivariate regression analysis also indicated that as much as 58% of the overall spatial and temporal variation in the oxidative potential of PM0.25 at these three locations can be explained by mobile emissions and SOA.

Geochemistry and carbon isotopic ratio for assessment of PM10 composition, source and seasonal trends in urban environment.

PubMed

Di Palma, A; Capozzi, F; Agrelli, D; Amalfitano, C; Giordano, S; Spagnuolo, V; Adamo, P

2018-08-01

Investigating the nature of PM 10 is crucial to differentiate sources and their relative contributions. In this study we compared the levels, and the chemical and mineralogical properties of PM 10 particles sampled in different seasons at monitoring stations representative of urban background, urban traffic and suburban traffic areas of Naples city. The aims were to relate the PM 10 load and characteristics to the location of the monitoring stations, to investigate the different sources contributing to PM 10 and to highlight PM 10 seasonal variability. Bulk analyses of chemical species in the PM 10 fraction included total carbon and nitrogen, δ 13 C and other 20 elements. Both natural and anthropogenic sources were found to contribute to the exceedances of the EU PM 10 limit values. The natural contribution was mainly related to marine aerosols and soil dust, as highlighted by X-ray diffractometry and SEM-EDS microscopy. The percentage of total carbon suggested a higher contribution of biogenic components to PM 10 in spring. However, this result was not supported by the δ 13 C values which were seasonally homogeneous and not sufficient to extract single emission sources. No significant differences, in terms of PM 10 load and chemistry, were observed between monitoring stations with different locations, suggesting a homogeneous distribution of PM 10 on the studied area in all seasons. The anthropogenic contribution to PM 10 seemed to dominate in all sites and seasons with vehicular traffic acting as a main source mostly by generation of non-exhaust emissions Our findings reinforce the need to focus more on the analysis of PM 10 in terms of quality than of load, to reconsider the criteria for the classification and the spatial distribution of the monitoring stations within urban and suburban areas, with a special attention to the background location, and to emphasize all the policies promoting sustainable mobility and reduction of both exhaust and not-exhaust traffic-related emissions. Copyright © 2018 Elsevier Ltd. All rights reserved.

QUASI-STAR JETS AS UNIDENTIFIED GAMMA-RAY SOURCES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czerny, Bozena; Sikora, Marek; Janiuk, Agnieszka

2012-08-10

Gamma-ray catalogs contain a considerable amount of unidentified sources. Many of these are located out of the Galactic plane and therefore may have extragalactic origin. Here we assume that the formation of massive black holes in galactic nuclei proceeds through a quasi-star stage and consider the possibility of jet production by such objects. Those jets would be the sources of collimated synchrotron and Compton emission, extending from radio to gamma rays. The expected lifetimes of quasi-stars are of the order of million of years while the jet luminosities, somewhat smaller than that of quasar jets, are sufficient to account formore » the unidentified gamma-ray sources. The jet emission dominates over the thermal emission of a quasi-star in all energy bands, except when the jet is not directed toward an observer. The predicted synchrotron emission peaks in the IR band, with the flux close to the limits of the available IR all sky surveys. The ratio of the gamma-ray flux to the IR flux is found to be very large ({approx}60), much larger than in BL Lac objects but reached by some radio-loud quasars. On the other hand, radio-loud quasars show broad emission lines while no such lines are expected from quasi-stars. Therefore, the differentiation between various scenarios accounting for the unidentified gamma-ray sources will be possible at the basis of the photometry and spectroscopy of the IR/optical counterparts.« less

Fermi-Lat Observations of High-Energy Gamma-Ray Emission Toward the Galactic Center

NASA Technical Reports Server (NTRS)

Ajello, M.; Albert, A.; Atwood, W.B.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Brandt, T. J.;

Isotopes, Inventories and Seasonality: Unraveling Methane Source Distribution in the Complex Landscapes of the United Kingdom.

NASA Astrophysics Data System (ADS)

Lowry, D.; Fisher, R. E.; Zazzeri, G.; Lanoisellé, M.; France, J.; Allen, G.; Nisbet, E. G.

2017-12-01

Unlike the big open landscapes of many continents with large area sources dominated by one particular methane emission type that can be isotopically characterized by flight measurements and sampling, the complex patchwork of urban, fossil and agricultural methane sources across NW Europe require detailed ground surveys for characterization (Zazzeri et al., 2017). Here we outline the findings from multiple seasonal urban and rural measurement campaigns in the United Kingdom. These surveys aim to: 1) Assess source distribution and baseline in regions of planned fracking, and relate to on-site continuous baseline climatology. 2) Characterize spatial and seasonal differences in the isotopic signatures of the UNFCCC source categories, and 3) Assess the spatial validity of the 1 x 1 km UK inventory for large continuous emitters, proposed point sources, and seasonal / ephemeral emissions. The UK inventory suggests that 90% of methane emissions are from 3 source categories, ruminants, landfill and gas distribution. Bag sampling and GC-IRMS delta13C analysis shows that landfill gives a constant signature of -57 ±3 ‰ throughout the year. Fugitive gas emissions are consistent regionally depending on the North Sea supply regions feeding the network (-41 ± 2 ‰ in N England, -37 ± 2 ‰ in SE England). Ruminant, mostly cattle, emissions are far more complex as these spend winters in barns and summers in fields, but are essentially a mix of 2 end members, breath at -68 ±3 ‰ and manure at -51 ±3 ‰, resulting in broad summer field emission plumes of -64 ‰ and point winter barn emission plumes of -58 ‰. The inventory correctly locates emission hotspots from landfill, larger sewage treatment plants and gas compressor stations, giving a broad overview of emission distribution for regional model validation. Mobile surveys are adding an extra layer of detail to this which, combined with isotopic characterization, has identified spatial distribution of gas pipe leaks, some persisting since 2013 (Zazzeri et al., 2015), and seasonality and spatial variability of livestock emissions. Importantly existing significant gas leaks close to proposed fracking sites have been characterized so that any emissions to atmosphere with a different isotopic signature will be detected. Zazzeri, G., Atm. Env. 110, 151-162 (2015); Zazzeri, G., Sci. Rep. 7, 4854 (2017).

A Neighboring Dwarf Irregular Galaxy Hidden by the Milky Way

NASA Astrophysics Data System (ADS)

Massey, Philip; Henning, P. A.; Kraan-Korteweg, R. C.

2003-11-01

We have obtained VLA and optical follow-up observations of the low-velocity H I source HIZSS 3 discovered by Henning et al. and Rivers in a survey for nearby galaxies hidden by the disk of the Milky Way. Its radio characteristics are consistent with this being a nearby (~1.8 Mpc) low-mass dwarf irregular galaxy (dIm). Our optical imaging failed to reveal a resolved stellar population but did detect an extended Hα emission region. The location of the Hα source is coincident with a partially resolved H I cloud in the 21 cm map. Spectroscopy confirms that the Hα source has a similar radial velocity to that of the H I emission at this location, and thus we have identified an optical counterpart. The Hα emission (100 pc in diameter and with a luminosity of 1.4×1038 ergs s-1) is characteristic of a single H II region containing a modest population of OB stars. The galaxy's radial velocity and distance from the solar apex suggests that it is not a Local Group member, although a more accurate distance is needed to be certain. The properties of HIZSS 3 are comparable to those of GR 8, a nearby dIm with a modest amount of current star formation. Further observations are needed to characterize its stellar population, determine the chemical abundances, and obtain a more reliable distance estimate.

Spectral triangulation: a 3D method for locating single-walled carbon nanotubes in vivo

NASA Astrophysics Data System (ADS)

Lin, Ching-Wei; Bachilo, Sergei M.; Vu, Michael; Beckingham, Kathleen M.; Bruce Weisman, R.

2016-05-01

Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of favorable tissue transparency and low autofluorescence backgrounds in that region. Single-walled carbon nanotubes (SWCNTs) show well-known sharp SWIR spectral signatures and therefore have potential for noninvasive detection and imaging of cancer tumours, when linked to selective targeting agents such as antibodies. However, such applications face the challenge of sensitively detecting and localizing the source of SWIR emission from inside tissues. A new method, called spectral triangulation, is presented for three dimensional (3D) localization using sparse optical measurements made at the specimen surface. Structurally unsorted SWCNT samples emitting over a range of wavelengths are excited inside tissue phantoms by an LED matrix. The resulting SWIR emission is sampled at points on the surface by a scanning fibre optic probe leading to an InGaAs spectrometer or a spectrally filtered InGaAs avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We therefore gauge the SWCNT-probe distance by analysing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence can be clearly detected through at least 20 mm of tissue phantom, and the 3D locations of embedded SWCNT test samples are found with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate two embedded SWCNT sources at distinct positions.Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of favorable tissue transparency and low autofluorescence backgrounds in that region. Single-walled carbon nanotubes (SWCNTs) show well-known sharp SWIR spectral signatures and therefore have potential for noninvasive detection and imaging of cancer tumours, when linked to selective targeting agents such as antibodies. However, such applications face the challenge of sensitively detecting and localizing the source of SWIR emission from inside tissues. A new method, called spectral triangulation, is presented for three dimensional (3D) localization using sparse optical measurements made at the specimen surface. Structurally unsorted SWCNT samples emitting over a range of wavelengths are excited inside tissue phantoms by an LED matrix. The resulting SWIR emission is sampled at points on the surface by a scanning fibre optic probe leading to an InGaAs spectrometer or a spectrally filtered InGaAs avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We therefore gauge the SWCNT-probe distance by analysing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence can be clearly detected through at least 20 mm of tissue phantom, and the 3D locations of embedded SWCNT test samples are found with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate two embedded SWCNT sources at distinct positions. Electronic supplementary information (ESI) available: Details concerning instrumental design, experimental procedures, related experiments, and triangulation computations, plus a video showing operation of the scanner. See DOI: 10.1039/c6nr01376g

Wildfire and soil emissions of NOx and their consequences for ozone observed at a remote mountaintop site in Central California

NASA Astrophysics Data System (ADS)

Asher, E. C. C.; Caputi, D.; Conley, S. A.; Faloona, I. C.

2016-12-01

Nitric oxide (NOx) emissions contribute to the production of tropospheric ozone and the nutrient supply fueling primary production. Current global estimates indicate that biomass burning, including wildfires, and soil emissions represent 15 - 25 % of the total emissions. Yet estimates suggest that in North America during the summer, natural sources, including biomass burning, soil emissions and lightning, are responsible for nearly half of total emissions. Thus, as domestic air quality standards grow stricter and anthropogenic sources more regulated, constraining natural sources of NOx becomes critical. NOx concentrations in wildfire smoke differ based on the age of the plume, fire intensity and vegetation type. NOx soil emissions depend on soil moisture, soil temperature, soil porosity, and nitrogen storage. We present two years of NOx and ozone (O3) measurements from a remote mountaintop monitoring site located on Chews Ridge in the coastal mountains of Central California, airborne observations, and remotely sensed NO2 tropospheric columns retrieved using the Ozone Monitoring Instrument (OMI). We explore controls on NOx concentrations at Chews Ridge, in Monterey County, such as the age of wildfire smoke plumes and wildfire intensity (i.e. burning vs. smoldering), as well as soil moisture and precipitation, which can lead to pulsed NOx fluxes. Most recently our in situ observations fortuitously captured differing amounts of the active plume of the Soberanes wildfire, which to date has burned >45,000 acres and is expected to continue partially contained through August 2016. Implications of these episodic sources of NOx on the regional ozone budget will be discussed.

Global data bases on distribution, characteristics and methane emission of natural wetlands: Documentation of archived data tape

NASA Technical Reports Server (NTRS)

Matthews, Elaine

1989-01-01

Global digital data bases on the distribution and environmental characteristics of natural wetlands, compiled by Matthews and Fung (1987), were archived for public use. These data bases were developed to evaluate the role of wetlands in the annual emission of methane from terrestrial sources. Five global 1 deg latitude by 1 deg longitude arrays are included on the archived tape. The arrays are: (1) wetland data source, (2) wetland type, (3) fractional inundation, (4) vegetation type, and (5) soil type. The first three data bases on wetland locations were published by Matthews and Fung (1987). The last two arrays contain ancillary information about these wetland locations: vegetation type is from the data of Matthews (1983) and soil type from the data of Zobler (1986). Users should consult original publications for complete discussion of the data bases. This short paper is designed only to document the tape, and briefly explain the data sets and their initial application to estimating the annual emission of methane from natural wetlands. Included is information about array characteristics such as dimensions, read formats, record lengths, blocksizes and value ranges, and descriptions and translation tables for the individual data bases.

Complex molecules in Sagittarius B2(N): The importance of grain chemistry

NASA Technical Reports Server (NTRS)

Miao, Yanti; Mehringer, David M.; Kuan, Yi-Jheng; Snyder, Lewis E.

1995-01-01

The complex molecules vinyl cyanide (CH2CHCN), methyl formate (HCOOCH3), and ethyl cyanide (CH3CH2CN) were observed in the Sgr B2 star-forming region with the BIMA millimeter wavelength array. A region with diameter less than 0.1 pc toward the Sgr B2(N) molecular core is found to be the major source of these molecules. Also, this source is coincident with continuum emission from dust and a center of H2O maser activity. Ultracompact (UC) H 11 regions are located within 0.1 pc. Strikingly, none of these molecules is detected toward Sgr B2(M), a core located 1 minute south of Sgr B2(N). The existence of complex molecules, a large mass of dust, high-velocity H2O masers, and UC H 11 regions strongly suggests that the Sgr B2(N) region has just begun to form stars, while the absence of strong dust emission and large molecules suggests Sgr B2(M) is more evolved. The detection of large molecules coincident with continuum emission from dust supports the idea found in current chemical models that grain chemistry is of crucial importance for the formation of these molecules.

A rapid response air quality analysis system for use in projects having stringent quality assurance requirements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman, A.W.

1990-04-01

This paper describes an approach to solve air quality problems which frequently occur during iterations of the baseline change process. From a schedule standpoint, it is desirable to perform this evaluation in as short a time as possible while budgetary pressures limit the size of the staff available to do the work. Without a method in place to deal with baseline change proposal requests the environment analysts may not be able to produce the analysis results in the time frame expected. Using a concept called the Rapid Response Air Quality Analysis System (RAAS), the problems of timing and cost becomemore » tractable. The system could be adapted to assess other atmospheric pathway impacts, e.g., acoustics or visibility. The air quality analysis system used to perform the EA analysis (EA) for the Salt Repository Project (part of the Civilian Radioactive Waste Management Program), and later to evaluate the consequences of proposed baseline changes, consists of three components: Emission source data files; Emission rates contained in spreadsheets; Impact assessment model codes. The spreadsheets contain user-written codes (macros) that calculate emission rates from (1) emission source data (e.g., numbers and locations of sources, detailed operating schedules, and source specifications including horsepower, load factor, and duty cycle); (2) emission factors such as those published by the U.S. Environmental Protection Agency, and (3) control efficiencies.« less

Identification and elucidation of anthropogenic source contribution in PM10 pollutant: Insight gain from dispersion and receptor models.

PubMed

Roy, Debananda; Singh, Gurdeep; Yadav, Pankaj

2016-10-01

Source apportionment study of PM 10 (Particulate Matter) in a critically polluted area of Jharia coalfield, India has been carried out using Dispersion model, Principle Component Analysis (PCA) and Chemical Mass Balance (CMB) techniques. Dispersion model Atmospheric Dispersion Model (AERMOD) was introduced to simplify the complexity of sources in Jharia coalfield. PCA and CMB analysis indicates that monitoring stations near the mining area were mainly affected by the emission from open coal mining and its associated activities such as coal transportation, loading and unloading of coal. Mine fire emission also contributed a considerable amount of particulate matters in monitoring stations. Locations in the city area were mostly affected by vehicular, Liquid Petroleum Gas (LPG) & Diesel Generator (DG) set emissions, residential, and commercial activities. The experimental data sampling and their analysis could aid understanding how dispersion based model technique along with receptor model based concept can be strategically used for quantitative analysis of Natural and Anthropogenic sources of PM 10 . Copyright © 2016. Published by Elsevier B.V.

An ultrasound-guided fluorescence tomography system: design and specification

NASA Astrophysics Data System (ADS)

D'Souza, Alisha V.; Flynn, Brendan P.; Kanick, Stephen C.; Torosean, Sason; Davis, Scott C.; Maytin, Edward V.; Hasan, Tayyaba; Pogue, Brian W.

2013-03-01

An ultrasound-guided fluorescence molecular tomography system is under development for in vivo quantification of Protoporphyrin IX (PpIX) during Aminolevulinic Acid - Photodynamic Therapy (ALA-PDT) of Basal Cell Carcinoma. The system is designed to combine fiber-based spectral sampling of PPIX fluorescence emission with co-registered ultrasound images to quantify local fluorophore concentration. A single white light source is used to provide an estimate of the bulk optical properties of tissue. Optical data is obtained by sequential illumination of a 633nm laser source at 4 linear locations with parallel detection at 5 locations interspersed between the sources. Tissue regions from segmented ultrasound images, optical boundary data, white light-informed optical properties and diffusion theory are used to estimate the fluorophore concentration in these regions. Our system and methods allow interrogation of both superficial and deep tissue locations up to PpIX concentrations of 0.025ug/ml.

PMF and PSCF based source apportionment of PM2.5 at a regional background site in North China

NASA Astrophysics Data System (ADS)

Zong, Zheng; Wang, Xiaoping; Tian, Chongguo; Chen, Yingjun; Fu, Shanfei; Qu, Lin; Ji, Ling; Li, Jun; Zhang, Gan

2018-05-01

To apportion regional PM2.5 (atmospheric particles with aerodynamic diameter < 2.5 μm) source types and their geographic pattern in North China, 120 daily PM2.5 samples on Beihuangcheng Island (BH, a regional background site in North China) were collected from August 20th, 2014 to September 15th, 2015 showing one-year period. After the chemical analyses on carbonaceous species, water-soluble ions and inorganic elements, various approaches, such as Mann-Kendall test, chemical mass closure, ISORROPIA II model, Positive Matrix Factorization (PMF) linked with Potential Source Contribution Function (PSCF), were used to explore the PM2.5 speciation, sources, and source regions. Consequently, distinct seasonal variations of PM2.5 and its main species were found and could be explained by varying emission source characteristics. Based on PMF model, seven source factors for PM2.5 were identified, which were coal combustion + biomass burning, vehicle emission, mineral dust, ship emission, sea salt, industry source, refined chrome industry with the contribution of 48.21%, 30.33%, 7.24%, 6.63%, 3.51%, 3.2%, and 0.88%, respectively. In addition, PSCF analysis using the daily contribution of each factor from PMF result suggested that Shandong peninsula and Hebei province were identified as the high potential region for coal combustion + biomass burning; Beijing-Tianjin-Hebei (BTH) region was the main source region for industry source; Bohai Sea and East China Sea were found to be of high source potential for ship emission; Geographical region located northwest of BH Island was possessed of high probability for sea salt; Mineral dust presumably came from the region of Mongolia; Refined chrome industry mostly came from Liaoning, Jilin province; The vehicle emission was primarily of BTH region origin, centring on metropolises, such as Beijing and Tianjin. These results provided precious implications for PM2.5 control strategies in North China.

Industrial point source CO2 emission strength estimation with aircraft measurements and dispersion modelling.

PubMed

Carotenuto, Federico; Gualtieri, Giovanni; Miglietta, Franco; Riccio, Angelo; Toscano, Piero; Wohlfahrt, Georg; Gioli, Beniamino

2018-02-22

CO 2 remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO 2 emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO 2 industrial point source, located in Biganos, France. CO 2 density measurements were obtained by applying the mass balance method, while CO 2 emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.

Comparisons of MOVES Light-duty Gasoline NOx Emission Rates with Real-world Measurements

NASA Astrophysics Data System (ADS)

Choi, D.; Sonntag, D.; Warila, J.

2017-12-01

Recent studies have shown differences between air quality model estimates and monitored values for nitrogen oxides. Several studies have suggested that the discrepancy between monitored and modeled values is due to an overestimation of NOx from mobile sources in EPA's emission inventory, particularly for light-duty gasoline vehicles. EPA's MOtor Vehicle Emission Simulator (MOVES) is an emission modeling system that estimates emissions for cars, trucks and other mobile sources at the national, county, and project level for criteria pollutants, greenhouse gases, and air toxics. Studies that directly measure vehicle emissions provide useful data for evaluating MOVES when the measurement conditions are properly accounted for in modeling. In this presentation, we show comparisons of MOVES2014 to thousands of real-world NOx emissions measurements from individual light-duty gasoline vehicles. The comparison studies include in-use vehicle emissions tests conducted on chassis dynamometer tests in support of Denver, Colorado's Vehicle Inspection & Maintenance Program and remote sensing data collected using road-side instruments in multiple locations and calendar years in the United States. In addition, we conduct comparisons of MOVES predictions to fleet-wide emissions measured from tunnels. We also present details on the methodology used to conduct the MOVES model runs in comparing to the independent data.

GeV Emission in the Region of HESS J1809‑193 and HESS J1813‑178: Is HESS J1809‑193 a Proton Pevatron?

NASA Astrophysics Data System (ADS)

Araya, Miguel

2018-05-01

HESS J1809‑193 is an unidentified TeV source discovered by the High Energy Stereoscopic System and originally classified as a pulsar wind nebula (PWN) candidate associated with the pulsar PSR J1809‑1917. However, a recent study of deep radio observations and the interstellar medium near the source has found evidence for a hadronic scenario for the gamma-rays. Here, a detailed study of the GeV emission in the region using data from the Fermi-LAT is presented. The GeV emission has an extended morphology in the region of the TeV emission and the overall spectrum can be accounted for by a cosmic-ray population having a simple power-law spectrum with energies extending up to 1 PeV. However, the spectrum at tens of TeV should be observed more deeply in the future to confirm its hadronic nature, and other scenarios involving combinations of leptonic and hadronic emission from several of the known supernova remnants in the region cannot be ruled out. The nearby TeV source HESS J1813‑178, thought to be a PWN, is also studied in detail at GeV energies and we find a region of significant emission that is much more extended than the TeV emission and whose spectrum is softer than expected from a PWN but similar to those seen in several star-forming regions that are believed to accelerate protons. There is marginal evidence for a GeV point source at the location of the X-ray PWN, beside the extended emission.

Type II Radio Bursts Observed by STEREO/Waves and Wind/Waves instruments

NASA Astrophysics Data System (ADS)

Krupar, V.; Magdalenic, J.; Zhukov, A.; Rodriguez, L.; Mierla, M.; Maksimovic, M.; Cecconi, B.; Santolik, O.

2013-12-01

Type II radio bursts are slow-drift emissions triggered by suprathermal electrons accelerated on shock fronts of propagating CMEs. We present several events at kilometric wavelengths observed by radio instruments onboard the STEREO and Wind spacecraft. The STEREO/Waves and Wind/Waves have goniopolarimetric (GP, also referred to as direction finding) capabilities that allow us to triangulate radio sources when an emission is observed by two or more spacecraft. As the GP inversion has high requirements on the signal-to-noise ratio we only have a few type II radio bursts with sufficient intensity for this analysis. We have compared obtained radio sources with white-light observations of STEREO/COR and STEREO/HI instruments. Our preliminary results indicate that radio sources are located at flanks of propagating CMEs.

New insights into the X-ray properties of nearby barred spiral galaxy NGC 1672

NASA Astrophysics Data System (ADS)

Jenkins, L. P.; Brnadt, W. N.; Colbert, E. J. M.; Levan, A. J.; Roberts, T. P.; Ward, M. J.; Zezas, A.

2008-02-01

We present some preliminary results from new Chandra and XMM-Newton X-ray observations of the nearby barred spiral galaxy NGC1672. It shows dramatic nuclear and extra-nuclear star formation activity, including starburst regions located near each end of its strong bar, both of which host ultraluminous X-ray sources (ULXs). With the new high-spatial-resolution Chandra imaging, we show for the first time that NGC1672 possesses a faint ($L(X)~10^39 erg/s), hard central X-ray source surrounded by an X-ray bright circumnuclear starburst ring that dominates the X-ray emission in the region. The central source may represent low-level AGN activity, or alternatively the emission from X-ray binaries associated with star-formation in the nucleus.

Supply Ventilation and Prevention of Carbon Monoxide (II) Ingress into Building Premises

NASA Astrophysics Data System (ADS)

Litvinova, N. A.

2017-11-01

The article contains the relationships of carbon monoxide (II) concentration versus height-above-ground near buildings derived based on results of studies. The results of studies are crucial in preventing external pollutants ingress into a ventilation system. Being generated by external emission sources, such as motor vehicles and city heating plants, carbon monoxide (II) enters the premises during operation of a supply ventilation system. Fresh air nomographic charts were drawn to select the height of a fresh air intake into the ventilation system. Nomographic charts take into account external sources. The selected emission sources are located at various levels above ground relative to the building. The recommendations allow designing supply ventilation taking into account the quality of ambient air through the whole building height.

Methane sources in Hong Kong - identification by mobile measurement and isotopic analysis

NASA Astrophysics Data System (ADS)

Fisher, Rebecca; Brownlow, Rebecca; Lowry, David; Lanoisellé, Mathias; Nisbet, Euan

2017-04-01

Hong Kong (22.4°N, 114.1°E) has a wide variety of natural and anthropogenic sources of methane within a small densely populated area (1106 km2, population ˜7.3 million). These include emissions from important source categories that have previously been poorly studied in tropical regions such as agriculture and wetlands. According to inventories (EDGAR v.4.2) anthropogenic methane emissions are mainly from solid waste disposal, wastewater disposal and fugitive leaks from oil and gas. Methane mole fraction was mapped out across Hong Kong during a mobile measurement campaign in July 2016. This technique allows rapid detection of the locations of large methane emissions which may focus targets for efforts to reduce emissions. Methane is mostly emitted from large point sources, with highest concentrations measured close to active landfill sites, sewage works and a gas processing plant. Air samples were collected close to sources (landfills, sewage works, gas processing plant, wetland, rice, traffic, cows and water buffalo) and analysed by mass spectrometry to determine the δ13C isotopic signatures to extend the database of δ13C isotopic signatures of methane from tropical regions. Isotopic signatures of methane sources in Hong Kong range from -70 ‰ (cows) to -37 ‰ (gas processing). Regular sampling of air for methane mole fraction and δ13C has recently begun at the Swire Institute of Marine Science, situated at Cape d'Aguilar in the southeast of Hong Kong Island. This station receives air from important source regions: southerly marine air from the South China Sea in summer and northerly continental air in winter and measurements will allow an integrated assessment of emissions from the wider region.

Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of particulate matter from wood and dung cooking fires, brick kilns, generators, trash and crop residue burning

NASA Astrophysics Data System (ADS)

Stone, Elizabeth; Jayarathne, Thilina; Stockwell, Chelsea; Christian, Ted; Bhave, Prakash; Siva Praveen, Puppala; Panday, Arnico; Adhikari, Sagar; Maharjan, Rashmi; Goetz, Doug; DeCarlo, Peter; Saikawa, Eri; Yokelson, Robert

2016-04-01

The Nepal Ambient Monitoring and Source Testing Experiment (NAMASTE) field campaign targeted the in situ characterization of widespread and under-sampled combustion sources. In Kathmandu and the Terai, southern Nepal's flat plains, samples of fine particulate matter (PM2.5) were collected from wood and dung cooking fires (n = 22), generators (n = 2), groundwater pumps (n = 2), clamp kilns (n = 3), zig-zag kilns (n = 3), trash burning (n = 4), one heating fire, and one crop residue fire. Co-located measurements of carbon dioxide, carbon monoxide, and volatile organic compounds allowed for the application of the carbon mass balance approach to estimate emission factors for PM2.5, elemental carbon, organic carbon, and water-soluble inorganic ions. Organic matter was chemically speciated using gas chromatography - mass spectrometry for polycyclic aromatic hydrocarbons, sterols, n-alkanes, hopanes, steranes, and levoglucosan, which accounted for 2-8% of the measured organic carbon. These data were used to develop molecular-marker based profiles for use in source apportionment modeling. This study provides quantitative emission factors for particulate matter and its constituents for many important combustion sources in Nepal and South Asia.

Numerical Simulation of Dispersion from Urban Greenhouse Gas Sources

NASA Astrophysics Data System (ADS)

Nottrott, Anders; Tan, Sze; He, Yonggang; Winkler, Renato

2017-04-01

Cities are characterized by complex topography, inhomogeneous turbulence, and variable pollutant source distributions. These features create a scale separation between local sources and urban scale emissions estimates known as the Grey-Zone. Modern computational fluid dynamics (CFD) techniques provide a quasi-deterministic, physically based toolset to bridge the scale separation gap between source level dynamics, local measurements, and urban scale emissions inventories. CFD has the capability to represent complex building topography and capture detailed 3D turbulence fields in the urban boundary layer. This presentation discusses the application of OpenFOAM to urban CFD simulations of natural gas leaks in cities. OpenFOAM is an open source software for advanced numerical simulation of engineering and environmental fluid flows. When combined with free or low cost computer aided drawing and GIS, OpenFOAM generates a detailed, 3D representation of urban wind fields. OpenFOAM was applied to model scalar emissions from various components of the natural gas distribution system, to study the impact of urban meteorology on mobile greenhouse gas measurements. The numerical experiments demonstrate that CH4 concentration profiles are highly sensitive to the relative location of emission sources and buildings. Sources separated by distances of 5-10 meters showed significant differences in vertical dispersion of plumes, due to building wake effects. The OpenFOAM flow fields were combined with an inverse, stochastic dispersion model to quantify and visualize the sensitivity of point sensors to upwind sources in various built environments. The Boussinesq approximation was applied to investigate the effects of canopy layer temperature gradients and convection on sensor footprints.

Using geomagnetic birefringence to locate sources of impulsive, terrestrial VHF signals detected by satellites on orbit

NASA Astrophysics Data System (ADS)

Jacobson, Abram R.; Shao, Xuan-Min

2001-07-01

The Earth's ionosphere is magnetized by the geomagnetic field and imposes birefringent modulation on VHF radio signals propagating through the ionosphere. Satellites viewing VHF emissions from terrestrial sources receive ordinary and extraordinary modes successively from each broadband pulse emitted by the source. The birefringent intermode frequency separation can be used to determine the value of ƒce cos β, where ƒce is the electron gyrofrequency and β is the angle between the wave vector k and the geomagnetic field B at the point where the VHF ray path intersects the ionosphere. Successive receptions of multiple signals (from the same source) cause variation in ƒce cos β, and from the resulting variation in the signal intermode frequency separation the source location on Earth can be inferred. We test the method with signals emitted by the Los Alamos Portable Pulser and received by the FORTE satellite.

Gravitational wave hotspots: Ranking potential locations of single-source gravitational wave emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simon, Joseph; Polin, Abigail; Lommen, Andrea

2014-03-20

The steadily improving sensitivity of pulsar timing arrays (PTAs) suggests that gravitational waves (GWs) from supermassive black hole binary (SMBHB) systems in the nearby universe will be detectable sometime during the next decade. Currently, PTAs assume an equal probability of detection from every sky position, but as evidence grows for a non-isotropic distribution of sources, is there a most likely sky position for a detectable single source of GWs? In this paper, a collection of Galactic catalogs is used to calculate various metrics related to the detectability of a single GW source resolvable above a GW background, assuming that everymore » galaxy has the same probability of containing an SMBHB. Our analyses of these data reveal small probabilities that one of these sources is currently in the PTA band, but as sensitivity is improved regions of consistent probability density are found in predictable locations, specifically around local galaxy clusters.« less

Infrared images of reflection nebulae and Orion's bar: Fluorescent molecular hydrogen and the 3.3 micron feature

NASA Technical Reports Server (NTRS)

Burton, Michael G.; Moorhouse, Alan; Brand, P. W. J. L.; Roche, Patrick F.; Geballe, T. R.

1989-01-01

Images were obtained of the (fluorescent) molecular hydrogen 1-0 S(1) line, and of the 3.3 micron emission feature, in Orion's Bar and three reflection nebulae. The emission from these species appears to come from the same spatial locations in all sources observed. This suggests that the 3.3 micron feature is excited by the same energetic UV-photons which cause the molecular hydrogen to fluoresce.

Impact of Aircraft Emissions on Air Quality in the Vicinity of Airports. Volume II. An Updated Model Assessment of Aircraft Generated Air Pollution at LAX, JFK, and ORD

DTIC Science & Technology

1980-07-01

Lfl 0 0.0 0ř 1𔃺 1ř 2Ŕ 2ř 3Ŕ 35 X (MILES) Figure 8. Map of Aircraf Line Sources at JFK 29 Table 8. Summary of Aircraft Emission for Hour 19 at JFK ... Airport Emissions (103 lbs) Location CO THC NOx Runways 0.08 0.05 0.52 Taxiways 3.94 2.30 0.15 Queue 1.21 0.64 0.05 Terminal 0.60 0.28 0.04 Total on

Detection of GeV Gamma-Rays from HESS J1534-571 and Multiwavelength Implications for the Origin of the Nonthermal Emission

NASA Astrophysics Data System (ADS)

Araya, Miguel

2017-07-01

HESS J1534-571 is a very high-energy gamma-ray source that was discovered by the H.E.S.S. observatory and reported as one of several new sources with a shell-like morphology at TeV energies, matching in size and location with the supernova remnant (SNR) G323.7-1.0 discovered in radio observations by the Molonglo Galactic Plane Survey. Many known TeV shells also show X-ray emission however, no X-ray counterpart has been seen for HESS J1534-571. The detection of a new GeV source using data from the Fermi satellite that is compatible in extension with the radio SNR and shows a very hard power-law spectrum ≤ft(\\tfrac{{dN}}{{dE}}\\propto {E}-1.35\\right) is presented here, together with the first broadband modeling of the nonthermal emission from this source. It is shown that leptonic emission is compatible with the known multiwavelength data and a corresponding set of physical source parameters is given. The required total energy budget in leptons is reasonable, ˜1.5 × 1048 erg for a distance to the object of 5 kpc. The new GeV observations imply that a hadronic scenario, on the other hand, requires a cosmic-ray spectrum that deviates considerably from theoretical expectations of particle acceleration.

Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth.

PubMed

Abeysekara, A U; Albert, A; Alfaro, R; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Avila Rojas, D; Ayala Solares, H A; Barber, A S; Bautista-Elivar, N; Becerril, A; Belmont-Moreno, E; BenZvi, S Y; Berley, D; Bernal, A; Braun, J; Brisbois, C; Caballero-Mora, K S; Capistrán, T; Carramiñana, A; Casanova, S; Castillo, M; Cotti, U; Cotzomi, J; Coutiño de León, S; De León, C; De la Fuente, E; Dingus, B L; DuVernois, M A; Díaz-Vélez, J C; Ellsworth, R W; Engel, K; Enríquez-Rivera, O; Fiorino, D W; Fraija, N; García-González, J A; Garfias, F; Gerhardt, M; González Muñoz, A; González, M M; Goodman, J A; Hampel-Arias, Z; Harding, J P; Hernández, S; Hernández-Almada, A; Hinton, J; Hona, B; Hui, C M; Hüntemeyer, P; Iriarte, A; Jardin-Blicq, A; Joshi, V; Kaufmann, S; Kieda, D; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linnemann, J T; Longinotti, A L; Luis Raya, G; Luna-García, R; López-Coto, R; Malone, K; Marinelli, S S; Martinez, O; Martinez-Castellanos, I; Martínez-Castro, J; Martínez-Huerta, H; Matthews, J A; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nellen, L; Newbold, M; Nisa, M U; Noriega-Papaqui, R; Pelayo, R; Pretz, J; Pérez-Pérez, E G; Ren, Z; Rho, C D; Rivière, C; Rosa-González, D; Rosenberg, M; Ruiz-Velasco, E; Salazar, H; Salesa Greus, F; Sandoval, A; Schneider, M; Schoorlemmer, H; Sinnis, G; Smith, A J; Springer, R W; Surajbali, P; Taboada, I; Tibolla, O; Tollefson, K; Torres, I; Ukwatta, T N; Vianello, G; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yapici, T; Yodh, G; Younk, P W; Zepeda, A; Zhou, H; Guo, F; Hahn, J; Li, H; Zhang, H

2017-11-17

The unexpectedly high flux of cosmic-ray positrons detected at Earth may originate from nearby astrophysical sources, dark matter, or unknown processes of cosmic-ray secondary production. We report the detection, using the High-Altitude Water Cherenkov Observatory (HAWC), of extended tera-electron volt gamma-ray emission coincident with the locations of two nearby middle-aged pulsars (Geminga and PSR B0656+14). The HAWC observations demonstrate that these pulsars are indeed local sources of accelerated leptons, but the measured tera-electron volt emission profile constrains the diffusion of particles away from these sources to be much slower than previously assumed. We demonstrate that the leptons emitted by these objects are therefore unlikely to be the origin of the excess positrons, which may have a more exotic origin. Copyright © 2017, American Association for the Advancement of Science.

Estimation of waste water treatment plant methane emissions: methodology and results from a short campaign

NASA Astrophysics Data System (ADS)

Yver-Kwok, C. E.; Müller, D.; Caldow, C.; Lebegue, B.; Mønster, J. G.; Rella, C. W.; Scheutz, C.; Schmidt, M.; Ramonet, M.; Warneke, T.; Broquet, G.; Ciais, P.

2013-10-01

This paper describes different methods to estimate methane emissions at different scales. These methods are applied to a waste water treatment plant (WWTP) located in Valence, France. We show that Fourier Transform Infrared (FTIR) measurements as well as Cavity Ring Down Spectroscopy (CRDS) can be used to measure emissions from the process to the regional scale. To estimate the total emissions, we investigate a tracer release method (using C2H2) and the Radon tracer method (using 222Rn). For process-scale emissions, both tracer release and chamber techniques were used. We show that the tracer release method is suitable to quantify facility- and some process-scale emissions, while the Radon tracer method encompasses not only the treatment station but also a large area around. Thus the Radon tracer method is more representative of the regional emissions around the city. Uncertainties for each method are described. Applying the methods to CH4 emissions, we find that the main source of emissions of the plant was not identified with certainty during this short campaign, although the primary source of emissions is likely to be from solid sludge. Overall, the waste water treatment plant represents a small part (3%) of the methane emissions of the city of Valence and its surroundings,which is in agreement with the national inventories.

Externally Heated Protostellar Cores in the Ophiuchus Star-Forming Region

NASA Technical Reports Server (NTRS)

Lindberg, Johan E.; Charnley, Steven B.; Jorgensen, Jes K.; Cordiner, Martin A.; Bjerkeli, Per

2017-01-01

We present APEX 218 GHz observations of molecular emission in a complete sample of embedded protostars in the Ophiuchus star-forming region. To study the physical properties of the cores, we calculate H2CO and c-C3H2 rotational temperatures, both of which are good tracers of the kinetic temperature of the molecular gas. We find that the H2CO temperatures range between 16K and 124K, with the highest H2CO temperatures toward the hot corino source IRAS 16293-2422 (69-124 K) and the sources in the rho Oph A cloud (23-49 K) located close to the luminous Herbig Be star S1, which externally irradiates the rho Oph A cores. On the other hand, the c-C3H2 rotational temperature is consistently low (7-17 K) in all sources. Our results indicate that the c-C3H2 emission is primarily tracing more shielded parts of the envelope whereas the H2CO emission (at the angular scale of the APEX beam; 3600 au in Ophiuchus) mainly traces the outer irradiated envelopes, apart from in IRAS?16293-2422, where the hot corino emission dominates. In some sources, a secondary velocity component is also seen, possibly tracing the molecular outflow.

Measurement of NOx fluxes from a tall tower in Beijing

NASA Astrophysics Data System (ADS)

Squires, Freya; Dunmore, Rachel; Lewis, Alastair; Vaughan, Adam; Mullinger, Neil; Nemitz, Eiko; Wild, Oliver; Zhang, Qiang; Hamilton, Jacqueline; Lee, James; Fu, Pingqing

2017-04-01

Nitrogen Oxides (NOx, the sum of nitrogen monoxide (NO) and nitrogen dioxide (NO2)) are significant anthropogenic pollutants emitted from most combustion processes. NOx is a precursor species to the formation of O3 and secondary aerosols and, in high concentrations, NO2 can have adverse effects on human health through action as a respiratory irritant. For these reasons, there has been increased focus on improving NOx emissions inventories, typically developed using 'bottom-up' estimates of emissions from their sources, which are used to predict current and future air quality and to guide abatement strategy. Recent studies have shown a discrepancy between NOx inventories and measured NOx emissions for UK cities, highlighting the limitations of bottom-up emissions inventories and the importance of accurate measurement data to improve the estimates. Similarly, inventories in China are associated with large uncertainties and are rapidly changing with time in response to economic development and new environmental regulation. Here, we present data collected as part of the Air Pollutants in Beijing (AIRPOLL-Beijing) campaign from an urban site located at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP, CAS) (39˚ 58'28"N, 116˚ 22'16"E) in central Beijing. NOx concentrations were measured using a state-of-the-art chemiluminescence instrument, sampling from an inlet at 100 metres on a meteorological tower. Measurements at 5 Hz coupled with wind vector data measured by a sonic anemometer located at the same height as the inlet allowed NOx emission fluxes to be calculated using the eddy covariance method. Measurements were made during the period 11/11/2016 - 10/12/2016 and compared to existing emission estimates from The Multi-resolution Emission Inventory for China (MEIC) inventory. It is anticipated that this work will be used to evaluate the accuracy of emissions inventories for Beijing, to develop improved emissions estimates and thus provide greater information about the sources of NOx in the city.

Airborne ultrafine particles in a Pacific Island country: Characteristics, sources and implications for human exposure.

PubMed

Isley, C F; Nelson, P F; Taylor, M P; Mazaheri, M; Morawska, L; Atanacio, A J; Stelcer, E; Cohen, D D; Morrison, Anthony L

2017-12-01

The Pacific Islands carry a perception of having clean air, yet emissions from transport and burning activities are of concern in regard to air quality and health. Ultrafine particle number concentrations (PNCs), one of the best metrics to demonstrate combustion emissions, have not been measured either in Suva or elsewhere in the Islands. This work provides insight into PNC variation across Suva and its relationship with particle mass (PM) concentration and composition. Measurements over a short monitoring campaign provide a vignette of conditions in Suva. Ambient PNCs were monitored for 8 day at a fixed location, and mobile PNC sampling for two days. These were compared with PM concentration (TSP, PM 10 , PM 2.5 , PM 1 ) and are discussed in relation to black carbon (BC) content and PM 2.5 sources, determined from elemental concentrations; for the October 2015 period and longer-term data. Whilst Suva City PM levels remained fairly low, PM 2.5  = 10-12 μg m -3 , mean PNC (1.64 ± 0.02 × 10 4  cm -3 ) was high compared to global data. PNCs were greater during mobile sampling, with means of 10.3 ± 1.4 × 10 4  cm -3 and 3.51 ± 0.07 × 10 4  cm -3 when travelling by bus and taxi, respectively. Emissions from road vehicles, shipping, diesel and open burning were identified as PM sources for the October 2015 period. Transport related ultrafine particle emissions had a significant impact on microscale ambient concentrations, with PNCs near roads being 1.5 to 2 times higher than nearby outdoor locations and peak PNCs occurring during peak traffic times. Further data, particularly on transport and wet-season exposures, are required to confirm results. Understanding PNC in Suva will assist in formulating effective air emissions control strategies, potentially reducing population exposure across the Islands and in developing countries with similar emission characteristics. Suva's PNC was high in comparison to global data; high exposures were related to transport and combustion emissions, which were also identified as significant PM 2.5 sources. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of methane emissions from five cold heavy oil production with sands (CHOPS) facilities.

PubMed

Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Knighton, W Berk; Zavala-Araiza, Daniel; Johnson, Matthew R; Tyner, David R

2018-03-07

Cold heavy oil production with sands (CHOPS) is a common oil extraction method in the Canadian provinces of Alberta and Saskatchewan that can result in significant methane emissions due to annular venting. Little is known about the magnitude of these emissions, nor their contributions to the regional methane budget. Here the authors present the results of field measurements of methane emissions from CHOPS wells and compare them with self-reported venting rates. The tracer ratio method was used not only to analyze total site emissions but at one site it was also used to locate primary emission sources and quantify their contributions to the facility-wide emission rate, revealing the annular vent to be a dominant source. Emissions measured from five different CHOPS sites in Alberta showed large discrepancies between the measured and reported rates, with emissions being mainly underreported. These methane emission rates are placed in the context of current reporting procedures and the role that gas-oil ratio (GOR) measurements play in vented volume estimates. In addition to methane, emissions of higher hydrocarbons were also measured; a chemical "fingerprint" associated with CHOPS wells in this region reveals very low emission ratios of ethane, propane, and aromatics versus methane. The results of this study may inform future studies of CHOPS sites and aid in developing policy to mitigate regional methane emissions. Methane measurements from cold heavy oil production with sand (CHOPS) sites identify annular venting to be a potentially major source of emissions at these facilities. The measured emission rates are generally larger than reported by operators, with uncertainty in the gas-oil ratio (GOR) possibly playing a large role in this discrepancy. These results have potential policy implications for reducing methane emissions in Alberta in order to achieve the Canadian government's goal of reducing methane emissions by 40-45% below 2012 levels within 8 yr.

PM₁₀ and PM₂.₅ sources at an insular location in the western Mediterranean by using source apportionment techniques.

PubMed

Pey, Jorge; Alastuey, Andrés; Querol, Xavier

2013-07-01

PM₁₀ and PM₂.₅ chemical composition has been determined at a suburban insular site in the Balearic Islands (Spain) during almost one and a half year. As a result, 200 samples with more than 50 chemical parameters analyzed have been obtained. The whole database has been analyzed by two receptor modelling techniques (Principal Component Analysis and Positive Matrix Factorisation) in order to identify the main PM sources. After that, regression analyses with respect to the PM mass concentrations were conducted to quantify the daily contributions of each source. Four common sources were identified by both receptor models: secondary nitrate coupled with vehicular emissions, secondary sulphate influenced by fuel-oil combustion, aged marine aerosols and mineral dust. In addition, PCA isolated harbour emissions and a mixed anthropogenic factor containing industrial emissions; whereas PMF isolated an additional mineral factor interpreted as road dust+harbour emissions, and a vehicular abrasion products factor. The use of both methodologies appeared complementary. Nevertheless, PMF sources by themselves were better differentiated. Besides these receptor models, a specific methodology to quantify African dust was also applied. The combination of these three source apportionment tools allowed the identification of 8 sources, being 4 of them mineral (African, regional, urban and harbour dusts). As a summary, 29% of PM₁₀ was attributed to natural sources (African dust, regional dust and sea spray), whereas the proportion diminished to 11% in PM₂.₅. Furthermore, the secondary sulphate source, which accounted for about 22 and 32% of PM₁₀ and PM₂.₅, is strongly linked to the aged polluted air masses residing over the western Mediterranean in the warm period. Copyright © 2013 Elsevier B.V. All rights reserved.

A Modeling Methodology to Support Evaluation Public Health Impacts on Air Pollution Reduction Programs

EPA Science Inventory

Environmental public health protection requires a good understanding of types and locations of pollutant emissions of health concern and their relationship to environmental public health indicators. Therefore, it is necessary to develop the methodologies, data sources, and tools...

40 CFR 63.5785 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards for Hazardous Air Pollutants: Reinforced Plastic Composites Production What This Subpart Covers... reinforced plastic composites production facility that is located at a major source of HAP emissions. Reinforced plastic composites production is limited to operations in which reinforced and/or nonreinforced...

Modeling the current and future role of particulate organic nitrates in the southeastern United States

EPA Science Inventory

Organic nitrates are an important aerosol constituent in locations where biogenic hydrocarbon emissions mix with anthropogenic NOx sources. While regional and global chemical transport models may include a representation of organic aerosol from monoterpene reactions with nitrate ...

Observations of premonitory acoustic emission and slip nucleation during a stick slip experiment in smooth faulted Westerly granite

USGS Publications Warehouse

Thompson, B.D.; Young, R.P.; Lockner, D.A.

2005-01-01

To investigate laboratory earthquakes, stick-slip events were induced on a saw-cut Westerly granite sample by triaxial loading at 150 MPa confining pressure. Acoustic emissions (AE) were monitored using an innovative continuous waveform recorder. The first motion of each stick slip was recorded as a large-amplitude AE signal. These events source locate onto the saw-cut fault plane, implying that they represent the nucleation sites of the dynamic failure stick-slip events. The precise location of nucleation varied between events and was probably controlled by heterogeneity of stress or surface conditions on the fault. The initial nucleation diameter of each dynamic instability was inferred to be less than 3 mm. A small number of AE were recorded prior to each macro slip event. For the second and third slip events, premonitory AE source mechanisms mimic the large scale fault plane geometry. Copyright 2005 by the American Geophysical Union.

Using air quality modeling to study source-receptor relationships between nitrogen oxides emissions and ozone exposures over the United States.

PubMed

Tong, Daniel Q; Muller, Nicholas Z; Kan, Haidong; Mendelsohn, Robert O

2009-11-01

Human exposure to ambient ozone (O(3)) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source-receptor relationships between nitrogen oxides (NO(x)) emissions and population exposure to ambient O(3) in 48 states over the continental United States. By removing NO(x) emissions from each state one at a time, we calculate the change in O(3) exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source-receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NO(x) emissions from upwind states contribute more to O(3) exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O(3) exposures in 90% of U.S. states. A state's NO(x) emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O(3) exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O(3) exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NO(x) is equal. In this study, the average O(3) exposures caused by one ton of NO(x) emissions ranges from -2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NO(x) emissions varies considerably over space.

Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

NASA Astrophysics Data System (ADS)

Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J. L.; Bruzzone, L.; Kofman, W.

2011-10-01

Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5MHz and 50MHz. Part of this frequency range overlaps with that of the natural Jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emission are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

NASA Astrophysics Data System (ADS)

Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J.-L.; Bruzzone, L.; Kofman, W.

2012-02-01

Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5 and 50 MHz. Part of this frequency range overlaps with that of the natural jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emissions are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

Infrared and Optical Spectroscopy of Protostars in the Elephant Trunk Nebula

NASA Astrophysics Data System (ADS)

Faied, Dohy; Reach, W. T.; Tappe, A.; Rho, J.

2006-12-01

We present Spitzer Space Telescope observations of the optically dark globule IC1396A. We have identified red objects located within the molecular globule to be Class I protostars, and objects scattered near the globule are found to be Class II T-Tauri stars surrounded by warm, luminous disks. We obtained simultaneous optical and infrared spectra (5.5 40 microns) with the Palomar Hale 200 inch telescope. The Class I sources were observed to have extremely red continua, rising at 24 microns, with deep silicate absorption at 9-11 microns, and weaker silicate absorption at around 12 microns. Some of these sources also display weak ice features such as CO2 and H2O. In contrast, the Class II sources have strong H-alpha emission and silicate emission features at 9-11 microns, indicative of circumstellar disks. These results all suggest that star formation within this globule is occurring at two different stages the first stage, leading to the Class II sources located in the center of the globule, and a second, very recent one (less than 100,000 yr ago) that is occurring within the globule. This second phase was likely triggered by the wind and radiation of the central O-type star of the IC 1396 H II region.

Application of OMI, SCIAMACHY and GOME-2 Satellite SO2 Retrievals for Detection of Large Emission Sources

NASA Technical Reports Server (NTRS)

Fioletov, V.E.; McLinden, C. A.; Krotkov, N.; Yang, K.; Loyola, D. G.; Valks, P.; Theys, N.; Van Roozendael, M.; Nowlan, C. R.; Chance, K.;

Improved provincial emission inventory and speciation profiles of anthropogenic non-methane volatile organic compounds: a case study for Jiangsu, China

NASA Astrophysics Data System (ADS)

Zhao, Yu; Mao, Pan; Zhou, Yaduan; Yang, Yang; Zhang, Jie; Wang, Shekou; Dong, Yanping; Xie, Fangjian; Yu, Yiyong; Li, Wenqing

2017-06-01

Non-methane volatile organic compounds (NMVOCs) are the key precursors of ozone (O3) and secondary organic aerosol (SOA) formation. Accurate estimation of their emissions plays a crucial role in air quality simulation and policy making. We developed a high-resolution anthropogenic NMVOC emission inventory for Jiangsu in eastern China from 2005 to 2014, based on detailed information of individual local sources and field measurements of source profiles of the chemical industry. A total of 56 NMVOCs samples were collected in nine chemical plants and were then analyzed with a gas chromatography - mass spectrometry system (GC-MS). Source profiles of stack emissions from synthetic rubber, acetate fiber, polyether, vinyl acetate and ethylene production, and those of fugitive emissions from ethylene, butanol and octanol, propylene epoxide, polyethylene and glycol production were obtained. Various manufacturing technologies and raw materials led to discrepancies in source profiles between our domestic field tests and foreign results for synthetic rubber and ethylene production. The provincial NMVOC emissions were calculated to increase from 1774 Gg in 2005 to 2507 Gg in 2014, and relatively large emission densities were found in cities along the Yangtze River with developed economies and industries. The estimates were larger than those from most other available inventories, due mainly to the complete inclusion of emission sources and to the elevated activity levels from plant-by-plant investigation in this work. Industrial processes and solvent use were the largest contributing sectors, and their emissions were estimated to increase, respectively, from 461 to 958 and from 38 to 966 Gg. Alkanes, aromatics and oxygenated VOCs (OVOCs) were the most important species, accounting for 25.9-29.9, 20.8-23.2 and 18.2-21.0 % to annual total emissions, respectively. Quantified with a Monte Carlo simulation, the uncertainties of annual NMVOC emissions vary slightly through the years, and the result for 2014 was -41 to +93 %, expressed as 95 % confidence intervals (CI). Reduced uncertainty was achieved compared to previous national and regional inventories, attributed partly to the detailed classification of emission sources and to the use of information at plant level in this work. Discrepancies in emission estimation were explored for the chemical and refinery sectors with various data sources and methods. Compared with the Multi-resolution Emission Inventory for China (MEIC), the spatial distribution of emissions in this work were more influenced by the locations of large point sources, and smaller emissions were found in urban area for developed cities in southern Jiangsu. In addition, discrepancies were found between this work and MEIC in the speciation of NMVOC emissions under the atmospheric chemistry mechanisms CB05 and SAPRC99. The difference in species OLE1 resulted mainly from the updated source profile of building paint use and the differences in other species from the varied sector contributions to emissions in the two inventories. The Community Multi-scale Air Quality (CMAQ) model simulation was applied to evaluate the two inventories, and better performance (indicated by daily 1 h maximum O3 concentrations in Nanjing) were found for January, April and October 2012 when the provincial inventory was used.

Emerging ecological datasets with application for modeling North American dust emissions

NASA Astrophysics Data System (ADS)

McCord, S.; Stauffer, N. G.; Garman, S.; Webb, N.

2017-12-01

In 2011 the US Bureau of Land Management (BLM) established the Assessment, Inventory and Monitoring (AIM) program to monitor the condition of BLM land and to provide data to support evidence-based management of multi-use public lands. The monitoring program shares core data collection methods with the Natural Resources Conservation Service's (NRCS) National Resources Inventory (NRI), implemented on private lands nationally. Combined, the two programs have sampled >30,000 locations since 2003 to provide vegetation composition, vegetation canopy height, the size distribution of inter-canopy gaps, soil texture and crusting information on rangelands and pasture lands across North America. The BLM implements AIM on more than 247.3 million acres of land across the western US, encompassing major dust source regions of the Chihuahuan, Sonoran, Mojave and Great Basin deserts, the Colorado Plateau, and potential high-latitude dust sources in Alaska. The AIM data are publicly available and can be used to support modeling of land surface and boundary-layer processes, including dust emission. While understanding US dust source regions and emission processes has been of national interest since the 1930s Dust Bowl, most attention has been directed to the croplands of the Great Plains and emission hot spots like Owens Lake, California. The magnitude, spatial extent and temporal dynamics of dust emissions from western dust source areas remain highly uncertain. Here, we use ensemble modeling with empirical and physically-based dust emission schemes applied to AIM monitoring data to assess regional-scale patterns of aeolian sediment mass fluxes and dust emissions. The analysis enables connections to be made between dust emission rates at source and other indicators of ecosystem function at the landscape scale. Emerging ecological datasets like AIM provide new opportunities to evaluate aeolian sediment transport responses to land surface conditions, potential interactions with disturbances (e.g., fire) and ecological change (e.g., invasive species), and the impacts of anthropogenic land use and land cover change.

Scaling isotopic emissions and microbes across a permafrost thaw landscape

NASA Astrophysics Data System (ADS)

Varner, R. K.; Palace, M. W.; Saleska, S. R.; Bolduc, B.; Braswell, B. H., Jr.; Crill, P. M.; Chanton, J.; DelGreco, J.; Deng, J.; Frolking, S. E.; Herrick, C.; Hines, M. E.; Li, C.; McArthur, K. J.; McCalley, C. K.; Persson, A.; Roulet, N. T.; Torbick, N.; Tyson, G. W.; Rich, V. I.

2017-12-01

High latitude peatlands are a significant source of atmospheric methane. This source is spatially and temporally heterogeneous, resulting in a wide range of emission estimates for the atmospheric budget. Increasing atmospheric temperatures are causing degradation of underlying permafrost, creating changes in surface soil moisture, the surface and sub-surface hydrological patterns, vegetation and microbial communities, but the consequences to rates and magnitudes of methane production and emissions are poorly accounted for in global budgets. We combined field observations, multi-source remote sensing data and biogeochemical modeling to predict methane dynamics, including the fraction derived from hydrogenotrophic versus acetoclastic microbial methanogenesis across Stordalen mire, a heterogeneous discontinuous permafrost wetland located in northernmost Sweden. Using the field measurement validated Wetland-DNDC biogeochemical model, we estimated mire-wide CH4 and del13CH4 production and emissions for 2014 with input from field and unmanned aerial system (UAS) image derived vegetation maps, local climatology and water table from insitu and remotely sensed data. Model simulated methanogenic pathways correlate with sequence-based observations of methanogen community composition in samples collected from across the permafrost thaw landscape. This approach enables us to link below ground microbial community composition with emissions and indicates a potential for scaling across broad areas of the Arctic region.

VizieR Online Data Catalog: First Fermi-LAT Inner Galaxy point source catalog (Ajello+, 2016)

NASA Astrophysics Data System (ADS)

Ajello, M.; Albert, A.; Atwood, W. B.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caputo, R.; Caragiulo, M.; Caraveo, P. A.; Cecchi, C.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Desiante, R.; di Venere, L.; Drell, P. S.; Favuzzi, C.; Ferrara, E. C.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Harding, A. K.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jogler, T.; Johannesson, G.; Johnson, A. S.; Kamae, T.; Karwin, C.; Knodlseder, J.; Kuss, M.; Larsson, S.; Latronico, L.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Malyshev, D.; Manfreda, A.; Mayer, M.; Mazziotta, M. N.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Raino, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Ritz, S.; Sanchez-Conde, M.; Parkinson, P. M. S.; Sgro, C.; Siskind, E. J.; Smith, D. A.; Spada, F.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, H.; Thayer, J. B.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Vianello, G.; Winer, B. L.; Wood, K. S.; Zaharijas, G.; Zimmer, S.

2018-01-01

The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of the emission toward the Galactic center (GC) in high-energy γ-rays. This paper describes the analysis of data taken during the first 62 months of the mission in the energy range 1-100GeV from a 15°x15° region about the direction of the GC. Specialized interstellar emission models (IEMs) are constructed to enable the separation of the γ-ray emissions produced by cosmic ray particles interacting with the interstellar gas and radiation fields in the Milky Way into that from the inner ~1kpc surrounding the GC, and that from the rest of the Galaxy. A catalog of point sources for the 15°x15° region is self-consistently constructed using these IEMs: the First Fermi-LAT Inner Galaxy Point Source Catalog (1FIG). The spatial locations, fluxes, and spectral properties of the 1FIG sources are presented, and compared with γ-ray point sources over the same region taken from existing catalogs. After subtracting the interstellar emission and point-source contributions a residual is found. If templates that peak toward the GC are used to model the positive residual the agreement with the data improves, but none of the additional templates tried account for all of its spatial structure. The spectrum of the positive residual modeled with these templates has a strong dependence on the choice of IEM. (2 data files).

Spontaneous light emission in complex nanostructures

NASA Astrophysics Data System (ADS)

Blanco, L. A.; García de Abajo, F. J.

2004-05-01

The spontaneous emission of an excited atom surrounded by different materials is studied in the framework of a semiclassical approach, where the transition dipole moment acts as the source of the emission field. The emission in the presence of semiinfinite media, metallic nanorings, spheres, gratings, and other complex geometries is investigated. Strong emission enhancement effects are obtained in some of these geometries associated to the excitation of plasmons (e.g., in nanorings or spheres). Furthermore, the emission is shown to take place only along narrow angular distributions when the atom is located inside a low-index dielectric and near its planar surface, or when metallic nanogratings are employed at certain resonant wave lengths. In particular, axially symmetric gratings made of real silver metal are considered, and both emission rate enhancement and focused far-field emission are achieved simultaneously when the grating is decorated with further nanostructures.

Effects of Source-Apportioned Coarse Particulate Matter (PM) ...

EPA Pesticide Factsheets

The Cleveland Multiple Air Pollutant Study (CMAPS) is one of the first comprehensive studies conducted to evaluate particulate matter (PM) over local and regional scales. Cleveland and the nearby Ohio River Valley impart significant regional sources of air pollution including coal combustion and steel production. Size-fractionated PM (coarse, fine and ultrafine) were collected from an urban site (G.T. Craig (GTC)) and a rural site (Chippewa Lake monitor (CLM) located 53 km southwest of Cleveland) from July 2009 to June 2010. Following collection, resulting speciated PM data were apportioned to identify local industrial emission sources for each size fraction and location, indicating these samples were enriched with resident emission sources. This study was designed to determine whether exposure of the CMAPS coarse PM contributes to the exacerbation of allergic asthma. Non-sensitized and house dust mite (HDM)-sensitized female Balb/cJ mice (n= 8/group) were exposed via oropharyngeal (OP) aspiration to 100 g coarse fractions of one of five source apportioned groups representative of distinct time periods of 4-6 weeks (traffic, coal, steel 1, steel 2, or winter PM) and OP challenge with HDM conducted 2 hr following dosing with PM. Two days later, airway responsiveness to methacholine aerosol was assessed in anesthetized ventilated control and HDM mice. The HDM-allergic mice demonstrated increased airway reactivity in comparison to control mice. Bronchoalveolar l

Modelling the diffuse dust emission around Orion

NASA Astrophysics Data System (ADS)

Saikia, Gautam; Shalima, P.; Gogoi, Rupjyoti

2018-06-01

We have studied the diffuse radiation in the surroundings of M42 using photometric data from the Galaxy Evolution Explorer (GALEX) in the far-ultraviolet (FUV) and infrared observations of the AKARI space telescope. The main source of the FUV diffuse emission is the starlight from the Trapezium stars scattered by dust in front of the nebula. We initially compare the diffuse FUV with the far-infrared (FIR) observations at the same locations. The FUV-IR correlations enable us to determine the type of dust contributing to this emission. We then use an existing model for studying the FUV dust scattering in Orion to check if it can be extended to regions away from the centre in a 10 deg radius. We obtain an albedo, α = 0.7 and scattering phase function asymmetry factor, g = 0.6 as the median values for our dust locations on different sides of the central Orion region. We find a uniform value of optical parameters across our sample of locations with the dust properties varying significantly from those at the centre of the nebula.

Real-world volatile organic compound emission rates from seated adults and children for use in indoor air studies.

PubMed

Stönner, C; Edtbauer, A; Williams, J

2018-01-01

Human beings emit many volatile organic compounds (VOCs) of both endogenous (internally produced) and exogenous (external source) origin. Here we present real-world emission rates of volatile organic compounds from cinema audiences (50-230 people) as a function of time in multiple screenings of three films. The cinema location and film selection allowed high-frequency measurement of human-emitted VOCs within a room flushed at a known rate so that emissions rates could be calculated for both adults and children. Gas-phase emission rates are analyzed as a function of time of day, variability during the film, and age of viewer. The average emission rates of CO 2 , acetone, and isoprene were lower (by a factor of ~1.2-1.4) for children under twelve compared to adults while for acetaldehyde emission rates were equivalent. Molecules influenced by exogenous sources such as decamethylcyclopentasiloxanes and methanol tended to decrease over the course of day and then rise for late evening screenings. These results represent average emission rates of people under real-world conditions and can be used in indoor air quality assessments and building design. Averaging over a large number of people generates emission rates that are less susceptible to individual behaviors. © 2017 The Authors. Indoor Air published by John Wiley & Sons Ltd.

Characterization of particulate emissions from Australian open-cut coal mines: Toward improved emission estimates.

PubMed

Richardson, Claire; Rutherford, Shannon; Agranovski, Igor

2018-06-01

Given the significance of mining as a source of particulates, accurate characterization of emissions is important for the development of appropriate emission estimation techniques for use in modeling predictions and to inform regulatory decisions. The currently available emission estimation methods for Australian open-cut coal mines relate primarily to total suspended particulates and PM 10 (particulate matter with an aerodynamic diameter <10 μm), and limited data are available relating to the PM 2.5 (<2.5 μm) size fraction. To provide an initial analysis of the appropriateness of the currently available emission estimation techniques, this paper presents results of sampling completed at three open-cut coal mines in Australia. The monitoring data demonstrate that the particulate size fraction varies for different mining activities, and that the region in which the mine is located influences the characteristics of the particulates emitted to the atmosphere. The proportion of fine particulates in the sample increased with distance from the source, with the coarse fraction being a more significant proportion of total suspended particulates close to the source of emissions. In terms of particulate composition, the results demonstrate that the particulate emissions are predominantly sourced from naturally occurring geological material, and coal comprises less than 13% of the overall emissions. The size fractionation exhibited by the sampling data sets is similar to that adopted in current Australian emission estimation methods but differs from the size fractionation presented in the U.S. Environmental Protection Agency methodology. Development of region-specific emission estimation techniques for PM 10 and PM 2.5 from open-cut coal mines is necessary to allow accurate prediction of particulate emissions to inform regulatory decisions and for use in modeling predictions. Development of region-specific emission estimation techniques for PM 10 and PM 2.5 from open-cut coal mines is necessary to allow accurate prediction of particulate emissions to inform regulatory decisions and for use in modeling predictions. Comprehensive air quality monitoring was undertaken, and corresponding recommendations were provided.

Fermi Large Area Telescope third source catalog

DOE PAGES

Acero, F.; Ackermann, M.; Ajello, M.; ...

2015-06-12

Here, we present the third Fermi Large Area Telescope (LAT) source catalog (3FGL) of sources in the 100 MeV–300 GeV range. Based on the first 4 yr of science data from the Fermi Gamma-ray Space Telescope mission, it is the deepest yet in this energy range. Relative to the Second Fermi LAT catalog, the 3FGL catalog incorporates twice as much data, as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse γ-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. The 3FGL catalog includes 3033 sources abovemore » $$4\\sigma $$ significance, with source location regions, spectral properties, and monthly light curves for each. Of these, 78 are flagged as potentially being due to imperfections in the model for Galactic diffuse emission. Twenty-five sources are modeled explicitly as spatially extended, and overall 238 sources are considered as identified based on angular extent or correlated variability (periodic or otherwise) observed at other wavelengths. For 1010 sources we have not found plausible counterparts at other wavelengths. More than 1100 of the identified or associated sources are active galaxies of the blazar class; several other classes of non-blazar active galaxies are also represented in the 3FGL. Pulsars represent the largest Galactic source class. As a result, from source counts of Galactic sources we estimate that the contribution of unresolved sources to the Galactic diffuse emission is ~3% at 1 GeV.« less

Diurnal cycling of urban aerosols under different weather regimes

NASA Astrophysics Data System (ADS)

Gregorič, Asta; Drinovec, Luka; Močnik, Griša; Remškar, Maja; Vaupotič, Janja; Stanič, Samo

2016-04-01

A one month measurement campaign was performed in summer 2014 in Ljubljana, the capital of Slovenia (population 280,000), aiming to study temporal and spatial distribution of urban aerosols and the mixing state of primary and secondary aerosols. Two background locations were chosen for this purpose, the first one in the city center (urban background - KIS) and the second one in the suburban background (Brezovica). Simultaneous measurements of black carbon (BC) and particle number size distribution of submicron aerosols (PM1) were conducted at both locations. In the summer season emission from traffic related sources is expected to be the main local contribution to BC concentration. Concentrations of aerosol species and gaseous pollutants within the planetary boundary layer are controlled by the balance between emission sources of primary aerosols and gases, production of secondary aerosols, chemical reactions of precursor gases under solar radiation and the rate of dilution by mixing within the planetary boundary layer (PBL) as well as with tropospheric air. Only local emission sources contribute to BC concentration during the stable PBL with low mixing layer height, whereas during the time of fully mixed PBL, regionally transported BC and other aerosols can contribute to the surface measurements. The study describes the diurnal behaviour of the submicron aerosol at the urban and suburban background location under different weather regimes. Particles in three size modes - nucleation (< 25 nm, NUM), Aitken (25 - 90 nm, AIM) and accumulation mode (90 - 800 nm, ACM), as well as BC mass concentration were evaluated separately for sunny, cloudy and rainy days, taking into account modelled values of PBL height. Higher particle number and black carbon concentrations were observed at the urban background (KIS) than at the suburban background location (Brezovica). Significant diurnal pattern of total particle concentration and black carbon concentration was observed at both locations, with a distinct morning and late afternoon peak. As a consequence of different PBL dynamics and atmospheric processes (photochemical effects, humidity, wind speed and direction), diurnal profile differs for sunny, cloudy and rainy days. Nucleation mode particles were found to be subjected to lower daily variation and only slightly influenced by weather, as opposed to Aitken and accumulation mode particles. The highest correlation between BC and particle number concentration is observed during stable atmospheric conditions in the night and morning hours and is attributed to different particle size modes, depending on the distance to local BC emission sources. In sunny weather conditions, correlation between BC and particle number concentration decreases during the day due to mixing in the atmosphere and formation of secondary aerosols. Black carbon aging and mixing with secondary aerosols was additionally studied on the aerosol samples taken from the morning to the evening of a sunny day using SEM-EDX technique.

A framework to spatially cluster air pollution monitoring sites in US based on the PM2.5 composition

PubMed Central

Austin, Elena; Coull, Brent A.; Zanobetti, Antonella; Koutrakis, Petros

2013-01-01

Background Heterogeneity in the response to PM2.5 is hypothesized to be related to differences in particle composition across monitoring sites which reflect differences in source types as well as climatic and topographic conditions impacting different geographic locations. Identifying spatial patterns in particle composition is a multivariate problem that requires novel methodologies. Objectives Use cluster analysis methods to identify spatial patterns in PM2.5 composition. Verify that the resulting clusters are distinct and informative. Methods 109 monitoring sites with 75% reported speciation data during the period 2003–2008 were selected. These sites were categorized based on their average PM2.5 composition over the study period using k-means cluster analysis. The obtained clusters were validated and characterized based on their physico-chemical characteristics, geographic locations, emissions profiles, population density and proximity to major emission sources. Results Overall 31 clusters were identified. These include 21 clusters with 2 or more sites which were further grouped into 4 main types using hierarchical clustering. The resulting groupings are chemically meaningful and represent broad differences in emissions. The remaining clusters, encompassing single sites, were characterized based on their particle composition and geographic location. Conclusions The framework presented here provides a novel tool which can be used to identify and further classify sites based on their PM2.5 composition. The solution presented is fairly robust and yielded groupings that were meaningful in the context of air-pollution research. PMID:23850585

NOx Emissions from Large Point Sources: Variability in Ozone Production, Resulting Health Damages and Economic Costs

NASA Astrophysics Data System (ADS)

Mauzerall, D. L.; Sultan, B.; Kim, N.; Bradford, D.

2004-12-01

We present a proof-of-concept analysis of the measurement of the health damage of ozone (O3) produced from nitrogen oxides (NOx = NO + NO2) emitted by individual large point sources in the eastern United States. We use a regional atmospheric model of the eastern United States, the Comprehensive Air Quality Model with Extensions (CAMx), to quantify the variable impact that a fixed quantity of NOx emitted from individual sources can have on the downwind concentration of surface O3, depending on temperature and local biogenic hydrocarbon emissions. We also examine the dependence of resulting ozone-related health damages on the size of the exposed population. The investigation is relevant to the increasingly widely used "cap and trade" approach to NOx regulation, which presumes that shifts of emissions over time and space, holding the total fixed over the course of the summer O3 season, will have minimal effect on the environmental outcome. By contrast, we show that a shift of a unit of NOx emissions from one place or time to another could result in large changes in the health effects due to ozone formation and exposure. We indicate how the type of modeling carried out here might be used to attach externality-correcting prices to emissions. Charging emitters fees that are commensurate with the damage caused by their NOx emissions would create an incentive for emitters to reduce emissions at times and in locations where they cause the largest damage.

40 CFR 63.6085 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards for Hazardous Air Pollutants for Stationary Combustion Turbines What This Subpart Covers § 63.6085... combustion turbine located at a major source of HAP emissions. (a) Stationary combustion turbine means all... comprising any simple cycle stationary combustion turbine, any regenerative/recuperative cycle stationary...

40 CFR 63.9782 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) National Emission Standards for Hazardous Air Pollutants for Refractory Products Manufacturing What This... operate a refractory products manufacturing facility that is, is located at, or is part of, a major source... this section. (a) A refractory products manufacturing facility is a plant site that manufactures...

Imaging thunder

NASA Astrophysics Data System (ADS)

Johnson, J. B.; Arechiga, R. O.; Thomas, R. J.; Edens, H. E.; Anderson, J.; Johnson, R. L.

2011-12-01

We use a network of broadband microphones, including a 4-element array, to locate the sources of thunder occurring during an electrical storm in central New Mexico on July 24th, 2009. Combined slowness search and distance ranging are used to identify thunder regions in three dimensions (out to 12 km) and for two overlapping frequency bands (1-10 and 4-40 Hz). Distinct thunder pulses are locatable and used to predict time-of-arrival to neighboring stations and to identify correlated phases across the network. Spatial correlation is also found between the thunder source regions and regions of VHF radiation as located by the New Mexico Lightning Mapping Array (LMA). Some of the misfit between the LMA and thunder locations is attributable to differences in excitation mechanisms of the respective radiation, which is related to current impulses in lightning channels (for thunder) and incremental ionization of the atmosphere (for VHF emissions).

Imaging thunder

NASA Astrophysics Data System (ADS)

Johnson, J. B.; Arechiga, R. O.; Thomas, R. J.; Edens, H. E.; Anderson, J.; Johnson, R.

2011-10-01

We use a network of broadband microphones, including a 4-element array, to locate the sources of thunder occurring during an electrical storm in central New Mexico on July 24th, 2009. Combined slowness search and distance ranging are used to identify thunder regions in three dimensions (out to 12 km) and for two overlapping frequency bands (1-10 and 4-40 Hz). Distinct thunder pulses are locatable and used to predict time-of-arrival to neighboring stations and to identify correlated phases across the network. Spatial correlation is also found between the thunder source regions and regions of very high frequency (VHF) radiation as located by the New Mexico Lightning Mapping Array (LMA). Some of the misfit between the LMA and thunder locations is attributable to differences in excitation mechanisms of the respective radiation, which is related to current impulses in lightning channels (for thunder) and incremental ionization of the atmosphere (for VHF emissions).

Natural or anthropogenic? On the origin of atmospheric sulfate deposition in the Andes of southeastern Ecuador

NASA Astrophysics Data System (ADS)

Makowski Giannoni, S.; Rollenbeck, R.; Trachte, K.; Bendix, J.

2014-10-01

Atmospheric sulfur deposition above certain limits can represent a threat to tropical forests, causing nutrient imbalances and mobilizing toxic elements that impact biodiversity and forest productivity. Atmospheric sources of sulfur deposited by precipitation have been roughly identified in only a few lowland tropical forests. Even scarcer are studies of this type in tropical mountain forests, many of them mega-diversity hotspots and especially vulnerable to acidic deposition. In these places, the topographic complexity and related streamflow conditions affect the origin, type, and intensity of deposition. Furthermore, in regions with a variety of natural and anthropogenic sulfur sources, like active volcanoes and biomass burning, no source emission data has been used for determining the contribution of each source to the deposition. The main goal of the current study is to evaluate sulfate (SO4- deposition by rain and occult precipitation at two topographic locations in a tropical mountain forest of southern Ecuador, and to trace back the deposition to possible emission sources applying back-trajectory modeling. To link upwind natural (volcanic) and anthropogenic (urban/industrial and biomass-burning) sulfur emissions and observed sulfate deposition, we employed state-of-the-art inventory and satellite data, including volcanic passive degassing as well. We conclude that biomass-burning sources generally dominate sulfate deposition at the evaluated sites. Minor sulfate transport occurs during the shifting of the predominant winds to the north and west. Occult precipitation sulfate deposition and likely rain sulfate deposition are mainly linked to biomass-burning emissions from the Amazon lowlands. Volcanic and anthropogenic emissions from the north and west contribute to occult precipitation sulfate deposition at the mountain crest Cerro del Consuelo meteorological station and to rain-deposited sulfate at the upriver mountain pass El Tiro meteorological station.

Mobile mapping of methane emissions and isoscapes

NASA Astrophysics Data System (ADS)

Takriti, Mounir; Ward, Sue; Wynn, Peter; Elias, Dafydd; McNamara, Niall

2017-04-01

Methane (CH4) is a potent greenhouse gas emitted from a variety of natural and anthropogenic sources. It is crucial to accurately and efficiently detect CH4 emissions and identify their sources to improve our understanding of changing emission patterns as well as to identify ways to curtail their release into the atmosphere. However, using established methods this can be challenging as well as time and resource intensive due to the temporal and spatial heterogeneity of many sources. To address this problem, we have developed a vehicle mounted mobile system that combines high precision CH4 measurements with isotopic mapping and dual isotope source characterisation. We here present details of the development and testing of a unique system for the detection and isotopic analysis of CH4 plumes built around a Picarro isotopic (13C/12C) gas analyser and a high precision Los Gatos greenhouse gas analyser. Combined with micrometeorological measurements and a mechanism for collecting discrete samples for high precision dual isotope (13C/12C, 2H/1H) analysis the system enables mapping of concentrations as well as directional and isotope based source verification. We then present findings from our mobile methane surveys around the North West of England. This area includes a variety of natural and anthropogenic methane sources within a relatively small geographical area, including livestock farming, urban and industrial gas infrastructure, landfills and waste water treatment facilities, and wetlands. We show that the system was successfully able to locate leaks from natural gas infrastructure and emissions from agricultural activities and to distinguish isotope signatures from these sources.

Comparison of Fine Structures of Electron Cyclotron Harmonic Emissions in Aurora

NASA Astrophysics Data System (ADS)

Labelle, J. W.; Dundek, M.

2015-12-01

Recent discoveries of emissions at four and five times the electron cyclotron frequency in aurora occuring under daylit conditions motivated the modification of radio receivers at South Pole Station, Antarctica, to measure fine structure of such emissions during two consecutive austral summers, 2013-4 and 2014-5. The experiment recorded 347 emission events over 376 days of observation. The seasonal distribution of these events revealed that successively higher harmonics require higher solar zenith angles for occurrence, as expected if they are generated at locations where the upper hybrid frequency matches the cyclotron harmonic, which for higher harmonics requires higher electron densities which are associated with higher solar zenith angles. Detailed examination of 21 cases in which two harmonics occur simultaneously showed that only rarely, about ten percent of the time, are the frequencies of the fine structures of the emissions in exact integer ratio (e.g., 3:2, 4:3, or 5:4 depending on which combination of harmonics is observed). In the remaining approximately ninety percent of the cases, the higher harmonic occurred at a lower ratio than the appropriate integer ratio, as expected if the harmonics are generated independently at their separate matching conditions in the bottomside ionosphere, where the upper hybrid frequency increases with altitude while the gyroharmonics decrease with altitude. (The bottomside is the most likely source of the emissions, since from there the mode converted Z-modes have access to ground-level.) Taken together, these results suggest that the dominant mechanism for the higher harmonics is independent generation at locations where the upper hybrid frequency matches each harmonic, i.e., at a separate source altitude for each harmonic. Generation of higher harmonics through coalescence of lower harmonic waves explains at most a small minority of events.

LOFAR discovery of radio emission in MACS J0717.5+3745

NASA Astrophysics Data System (ADS)

Bonafede, A.; Brüggen, M.; Rafferty, D.; Zhuravleva, I.; Riseley, C. J.; van Weeren, R. J.; Farnes, J. S.; Vazza, F.; Savini, F.; Wilber, A.; Botteon, A.; Brunetti, G.; Cassano, R.; Ferrari, C.; de Gasperin, F.; Orrú, E.; Pizzo, R. F.; Röttgering, H. J. A.; Shimwell, T. W.

2018-05-01

We present results from LOFAR and GMRT observations of the galaxy cluster MACS J0717.5+3745. The cluster is undergoing a violent merger involving at least four sub-clusters, and it is known to host a radio halo. LOFAR observations reveal new sources of radio emission in the Intra-Cluster Medium: (i) a radio bridge that connects the cluster to a head-tail radio galaxy located along a filament of galaxies falling into the main cluster, (ii) a 1.9 Mpc radio arc, that is located North West of the main mass component, (iii) radio emission along the X-ray bar, that traces the gas in the X-rays South West of the cluster centre. We use deep GMRT observations at 608 MHz to constrain the spectral indices of these new radio sources, and of the emission that was already studied in the literature at higher frequency. We find that the spectrum of the radio halo and of the relic at LOFAR frequency follows the same power law as observed at higher frequencies. The radio bridge, the radio arc, and the radio bar all have steep spectra, which can be used to constrain the particle acceleration mechanisms. We argue that the radio bridge could be caused by the re-acceleration of electrons by shock waves that are injected along the filament during the cluster mass assembly. Despite the sensitivity reached by our observations, the emission from the radio halo does not trace the emission of the gas revealed by X-ray observations. We argue that this could be due to the difference in the ratio of kinetic over thermal energy of the intra-cluster gas, suggested by X-ray observations.

Annual emissions of mercury to the atmosphere from natural sources in Nevada and California

USGS Publications Warehouse

Coolbaugh, M.F.; Gustin, M.S.; Rytuba, J.J.

2002-01-01

The impact of natural source emissions on atmospheric mercury concentrations and the biogeochemical cycle of mercury is not known. To begin to assess this impact, mercury emissions to the atmosphere were scaled up for three areas naturally enriched in mercury: the Steamboat Springs geothermal area, Nevada, the New Idria mercury mining district, California, and the Medicine Lake volcano, California. Data used to scale up area emissions included mercury fluxes, measured in-situ using field flux chambers, from undisturbed and disturbed geologic substrates, and relationships between mercury emissions and geologic rock types, soil mercury concentrations, and surface heat flux. At select locations mercury fluxes were measured for 24 h and the data were used to adjust fluxes measured at different times of the day to give an average daily flux. This adjustment minimized daily temporal variability, which is observed for mercury flux because of light and temperature effects. Area emissions were scaled spatially and temporally with GIS software. Measured fluxes ranged from 0.3 to approximately 50 ng m-2 h-1 at undisturbed sites devoid of mercury mineralization, and to greater than 10,000 ng m-2 h-1 from substrates that were in areas of mercury mining. Area-averaged fluxes calculated for bare soil at Steamboat Springs, New Idria, and Medicine Lake of 181, 9.2, and 2 ng m-2 h-1, respectively, are greater than fluxes previously ascribed to natural non-point sources, indicating that these sources may be more significant contributors of mercury to the atmosphere than previously realized.

Refined Use of Satellite Aerosol Optical Depth Snapshots to Constrain Biomass Burning Emissions in the GOCART Model

NASA Technical Reports Server (NTRS)

Petrenko, Mariya; Kahn, Ralph; Chin, Mian; Limbacher, James

2017-01-01

Simulations of biomass burning (BB) emissions in global chemistry and aerosol transport models depend on external inventories, which provide location and strength of burning aerosol sources. Our previous work (Petrenko et al., 2012) shows that satellite snapshots of aerosol optical depth (AOD) near the emitted smoke plume can be used to constrain model-simulated AOD, and effectively, the assumed source strength. We now refine the satellite-snapshot method and investigate applying simple multiplicative emission correction factors for the widely used Global Fire Emission Database version 3 (GFEDv3) emission inventory can achieve regional-scale consistency between MODIS AOD snapshots and the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. The model and satellite AOD are compared over a set of more than 900 BB cases observed by the MODIS instrument during the 2004, and 2006-2008 biomass burning seasons. The AOD comparison presented here shows that regional discrepancies between the model and satellite are diverse around the globe yet quite consistent within most ecosystems. Additional analysis of including small fire emission correction shows the complimentary nature of correcting for source strength and adding missing sources, and also indicates that in some regions other factors may be significant in explaining model-satellite discrepancies. This work sets the stage for a larger intercomparison within the Aerosol Inter-comparisons between Observations and Models (AeroCom) multi-model biomass burning experiment. We discuss here some of the other possible factors affecting the remaining discrepancies between model simulations and observations, but await comparisons with other AeroCom models to draw further conclusions.

Air pathway effects of nuclear materials production at the Hanford Site, 1983 to 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patton, G.W.; Cooper, A.T.

1993-10-01

This report describes the air pathway effects of Hanford Site operations from 1983 to 1992 on the local environment by summarizing the air concentrations of selected radionuclides at both onsite and offsite locations, comparing trends in environment concentrations to changing facility emissions, and briefly describing trends in the radiological dose to the hypothetical maximally exposed member of the public. The years 1983 to 1992 represent the last Hanford Site plutonium production campaign, and this report deals mainly with the air pathway effects from the 200 Areas, in which the major contributors to radiological emissions were located. An additional purpose formore » report was to review the environmental data for a long period of time to provide insight not available in an annual report format. The sampling and analytical systems used by the Surface Environmental Surveillance Project (SESP) to collect air samples during the period of this report were sufficiently sensitive to observe locally elevated concentrations of selected radionuclides near onsite source of emission as well as observing elevated levels, compared to distant locations, of some radionuclides at the down wind perimeter. The US DOE Derived Concentration Guides (DCGs) for airborne radionuclides were not exceeded for any air sample collected during 1983 to 1992, with annual average concentrations of all radionuclides at the downwind perimeter being considerably below the DCG values. Air emissions at the Hanford Site during the period of this report were dominated by releases from the PUREX Plant, with {sup 85}Kr being the major release on a curie basis and {sup 129}I being the major release on a radiological dose basis. The estimated potential radiological dose from Hanford Site point source emissions to the hypothetical maximally exposed individual (MEI) ranged from 0. 02 to 0.22 mrem/yr (effective dose equivalent), which is well below the DOE radiation limit to the public of 100 mrem/yr.« less

Estimating methane emissions from dairies in the Los Angeles Basin

NASA Astrophysics Data System (ADS)

Viatte, C.; Lauvaux, T.; Hedelius, J.; Parker, H. A.; Chen, J.; Jones, T.; Franklin, J.; Deng, A.; Gaudet, B.; Duren, R. M.; Verhulst, K. R.; Wunch, D.; Roehl, C. M.; Dubey, M. K.; Wofsy, S.; Wennberg, P. O.

2015-12-01

Inventory estimates of methane (CH4) emissions among the individual sources (mainly agriculture, energy production, and waste management) remain highly uncertain at regional and urban scales. Accurate atmospheric measurements can provide independent estimates to evaluate bottom-up inventories, especially in urban region, where many different CH4 sources are often confined in relatively small areas. Among these sources, livestock emissions, which are mainly originating from dairy cows, account for ~55% of the total CH4 emissions in California in 2013. This study aims to rigorously estimate the amount of CH4 emitted by the largest dairies in the Southern California region by combining measurements from four mobile ground-based spectrometers (EM27/SUN), in situ isotopic methane measurements from a CRDS analyzer (Picarro), and a high-resolution atmospheric transport model (the Weather Research and Forecasting model) in Large-Eddy Simulation mode. The remote sensing spectrometers measure the total column-averaged dry-air mole fractions of CH4 and CO2 (XCH4 and XCO2) in the near infrared region, providing information about total emissions of the dairies. Gradients measured by the four EM27 ranged from 0.2 to 22 ppb and from 0.7 to 3 ppm for XCH4 and XCO2, respectively. To assess the fluxes of the dairies, measurements of these gradients are used in conjunction with the local atmospheric dynamics simulated at 111 m resolution. Inverse modelling from WRF-LES is employed to resolve the spatial distribution of CH4 emissions in the domain. A Bayesian inversion and a Monte-Carlo approach were used to provide the CH4 emissions over the dairy with their associated uncertainties. The isotopic δ13C sampled at different locations in the area ranges from -40 ‰ to -55 ‰, indicating a mixture of anthropogenic and biogenic sources.

Technique to determine location of radio sources from measurements taken on spinning spacecraft

NASA Technical Reports Server (NTRS)

Fainberg, J.

1979-01-01

The procedure developed to extract average source direction and average source size from spin-modulated radio astronomy data measured on the IMP-6 spacecraft is described. Because all measurements are used, rather than just finding maxima or minima in the data, the method is very sensitive, even in the presence of large amounts of noise. The technique is applicable to all experiments with directivity characteristics. It is suitable for onboard processing on satellites to reduce the data flow to Earth. The application to spin-modulated nonpolarized radio astronomy data is made and includes the effects of noise, background, and second source interference. The analysis was tested with computer simulated data and the results agree with analytic predictions. Applications of this method with IMP-6 radio data have led to: (1) determination of source positions of traveling solar radio bursts at large distances from the Sun; (2) mapping of magnetospheric radio emissions by radio triangulation; and (3) detection of low frequency radio emissions from Jupiter and Saturn.

X-ray emission from the Pleiades cluster

NASA Technical Reports Server (NTRS)

Agrawal, P. C.; Singh, K. P.; Riegler, G. R.

1983-01-01

The detection and identification of H0344+24, a new X-ray source located in the Pleiades cluster, is reported, based on observations made with HEAO A-2 low-energy detector 1 in the 0.15-3.0-keV energy band in August, 1977. The 90-percent-confidence error box for the new source is centered at 03 h 44.1 min right ascension (1950), near the center star of the 500-star Pleiades cluster, 25-eta-Tau. Since no likely galactic or extragalactic source of X-rays was found in a catalog search of the error-box region, identification of the source with the Pleiades cluster is considered secure. X-ray luminosity of the source is calculated to be about 10 to the 32nd ergs/sec, based on a distance of 125 pc. The X-ray characteristics of the Pleiades stars are discussed, and it is concluded that H0344+24 can best be explained as the integrated X-ray emission of all the B and F stars in the cluster.

The First Detection of (O IV) from an Ultraluminous X-Ray Source with Spitzer. 2. Evidence for High Luminosity in Holmberg II ULX

DTIC Science & Technology

2010-01-01

from the accretion disk of the binary system and inconsistent with narrow beaming. We show that the emission nebula is matter- bounded both in the line...making them very dif- ficult to characterize. The ionization nebulae surrounding some ULXs have become critical for understanding the properties of...Abolmasov et al. 2007). It is located inside an ionized nebula (the “Foot nebula ”), and shows high- ionization optical emission lines coincident with

Ultraluminous X-ray Sources in NGC 6946.

NASA Astrophysics Data System (ADS)

Sánchez Cruces, Mónica; Rosado, Margarita; Fuentes-Carrera, Isaura L.

2016-07-01

Ultra-luminous X-ray sources (ULXs) are the most X-ray luminous off-nucleus objects in nearby galaxies with X-ray luminosities between 10^{39} - 10^{41} erg s^{-1} in the 0.5-10 keV band. Since these luminosities cannot be explained by the standard accretion of a stellar mass black hole, these sources are often associated with intermediate-mass black holes (IMBHs, 10^{2}-10^{4} solar masses). However significantly beamed stellar binary systems could also explain these luminosities. Observational knowledge of the angular distribution of the source emission is essential to decide between these two scenarios. In this work, we present the X-ray analysis of five ULXs in the spiral galaxy NGC 6949, along with the kinematical analysis of the ionized gas surrounding each of these sources. For all sources, X-ray observations reveal a typical ULX spectral shape (with a soft excess below 2 keV and a hard curvature above 2 keV) which can be fit with a power-law + multi-color disk model. However, even if ULXs are classified as point-like objects, one of the sources in this galaxy displays an elongated shape in the Chandra images. Regarding the analysis of the emission lines of the surrounding ˜300 pc around each ULX, scanning Fabry-Perot observations show composite profiles for three of the five ULXs. The main component of these profiles follows the global rotation of the galaxy, while the faint secondary component seems to be associated with asymmetrical gas expansion. These sources have also been located in archive images of NGC 6946 in different wavelengths in order to relate them to different physical processes occurring in this galaxy. Though ULXs are usually located in star formation regions, we find that two of the sources lie a few tenths of parsecs away from different HII regions. Based on the X-ray morphology of each ULX, the velocities and distribution of the surrounding gas, as well as the location of the source in the context of the whole galaxy, we give the most favorable scenario in each case in order to describe the multiwavelength properties of these sources.

Non-methane hydrocarbons source apportionment at different sites in Mexico City during 2002-2003

NASA Astrophysics Data System (ADS)

Vega, E.; Sanchez, G.; Molina, L.

2007-09-01

The atmospheric concentrations of a variety of non-methane hydrocarbons (NMHC) collected at different sites, representing urban and rural environments within Mexico City Metropolitan Area (MCMA) during 1997, 2002 and 2003 field campaigns, were compared and used as an input for the Chemical Mass Balance (CMB) receptor model to determine the source contribution of NMHC to the atmosphere. A common feature at all the locations was the dominance of alkenes (59%), aromatics (16%) and olefins (9%) in the average NMHC burden. At the urban sites the interquartile range of NMHC concentrations showed stabilization over this period with a slight increase in the concentrations of propane and butanes in the southwest site of the MCMA in 2003 due to the increased use of liquefied petroleum gas (LPG). The receptor model CMB version 8.0 was used to apportion the NMHC sources at six locations within the MCMA, representing the heavily industrialized, commercial, residential and rural areas. For the 2003 field campaign, the contribution of vehicular emissions dominated the NMHC concentrations (19.7%±7.1% for gasoline vehicles and 35.4%±17.5% for diesel vehicles) followed by the emissions of marketing and handling of LPG (29.9%±8.0%). The NMHC concentrations showed a weekly cycle with the highest levels towards the end of the week and lowest at weekend and beginning of the week, suggesting that both emissions and accumulations process play a key role in building up NMHC levels. The toluene to benzene ratio was used to determine photochemical ageing of the air samples during the 2003 field campaign. The database was divided into periods with similar wind circulation pattern; the results suggest that ageing process within the MCMA is generally suppressed by the amount of fresh emissions.

Fermi-LAT Observations of High-Energy Gamma-Ray Emission Toward the Galactic Center

DOE PAGES

Ajello, M.

2016-02-26

The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of the emission towards the Galactic centre (GC) in high-energy γ-rays. This paper describes the analysis of data taken during the first 62 months of the mission in the energy range 1 - 100 GeV from a 15° X15° region about the direction of the GC, and implications for the interstellar emissions produced by cosmic ray (CR) particles interacting with the gas and radiation fields in the inner Galaxy and for the point sources detected. Specialised interstellar emission models (IEMs) are constructed that enable separation ofmore » the γ-ray emission from the inner ~ 1 kpc about the GC from the fore- and background emission from the Galaxy. Based on these models, the interstellar emission from CR electrons interacting with the interstellar radiation field via the inverse Compton (IC) process and CR nuclei inelastically scattering off the gas producing γ-rays via π⁰ decays from the inner ~ 1 kpc is determined. The IC contribution is found to be dominant in the region and strongly enhanced compared to previous studies. A catalog of point sources for the 15 °X 15 °region is self-consistently constructed using these IEMs: the First Fermi–LAT Inner Galaxy point source Catalog (1FIG). The spatial locations, fluxes, and spectral properties of the 1FIG sources are presented, and compared with γ-ray point sources over the same region taken from existing catalogs, including the Third Fermi–LAT Source Catalog (3FGL). In general, the spatial density of 1FIG sources differs from those in the 3FGL, which is attributed to the different treatments of the interstellar emission and energy ranges used by the respective analyses. Three 1FIG sources are found to spatially overlap with supernova remnants (SNRs) listed in Green’s SNR catalog; these SNRs have not previously been associated with high-energy γ-ray sources. Most 3FGL sources with known multi-wavelength counterparts are also found. However, the majority of 1FIG point sources are unassociated. After subtracting the interstellar emission and point-source contributions from the data a residual is found that is a sub-dominant fraction of the total flux. But, it is brighter than the γ-ray emission associated with interstellar gas in the inner ~ 1 kpc derived for the IEMs used in this paper, and comparable to the integrated brightness of the point sources in the region for energies & 3 GeV. If spatial templates that peak toward the GC are used to model the positive residual and included in the total model for the 1515°X° region, the agreement with the data improves, but they do not account for all the residual structure. The spectrum of the positive residual modelled with these templates has a strong dependence on the choice of IEM.« less

Solar absorption Fourier Transform Infrared spectroscopy applied to detect SO2 plumes above Mexico City

NASA Astrophysics Data System (ADS)

Aldana-Vazquez, A.; Stremme, W.; Grutter, M.

2010-12-01

There are sources of emissions of sulfur dioxide (SO2) that disperse to the Metropolitan Area of Mexico City (MCMA). The sources can be divided into three categories: a) The active Popocatepetl volcano located 70 km SE from the center of Mexico City, b) the industrial area located approximately 70 km to the and c) other local sources located in the surroundings from the measurement.. Solar absorption infrared spectra are being recorded since 2007 above the campus of the Universidad Nacional Autónoma de México (UNAM, 19.33 N, 99.18 W, 2260 m.a.s.l.). The column of SO2 was retrieved from all the spectra recorded in 2008 with the retrieval code SFIT2. Enhancement of the SO2 column could be identified in different time periods. The origin of the detected SO2 is determined by correlating the SO2 column with a) its surface concentration measured in the surroundings by the monitoring stations from the city’s monitoring network of (RAMA), b) the height of the mixing layer measured at UNAM, and c) meteorological wind data (REDMET, NCEP-NARR, and SMN). The result shows that the extraordinary events are correlated with the mentioned sources, and the analysis confirms prior studies that the plume travels at different altitudes. The plume of the Popocatepetl volcano is transported according to the wind at 5000 m.a.s.l. while emissions from the industrial area northwest of the MCMA are dispersed at lower altitudes within the mixing layer.

Time-resolved acoustic emission tomography in the laboratory: tracking localised damage in rocks

NASA Astrophysics Data System (ADS)

Brantut, N.

2017-12-01

Over the past three decades, there has been tremendous technological developments of laboratory equipment and studies using acoustic emission and ultrasonic monitoring of rock samples during deformation. Using relatively standard seismological techniques, acoustic emissions can be detected, located in space and time, and source mechanisms can be obtained. In parallel, ultrasonic velocities can be measured routinely using standard pulse-receiver techniques.Despite these major developments, current acoustic emission and ultrasonic monitoring systems are typically used separately, and the poor spatial coverage of acoustic transducers precludes performing active 3D tomography in typical laboratory settings.Here, I present an algorithm and software package that uses both passive acoustic emission data and active ultrasonic measurements to determine acoustic emission locations together with the 3D, anisotropic P-wave structure of rock samples during deformation. The technique is analogous to local earthquake tomography, but tailored to the specificities of small scale laboratory tests. The fast marching method is employed to compute the forward problem. The acoustic emission locations and the anisotropic P-wave field are jointly inverted using the Quasi-Newton method.The method is used to track the propagation of compaction bands in a porous sandstone deformed in the ductile, cataclastic flow regime under triaxial stress conditions. Near the yield point, a compaction front forms at one end of the sample, and slowly progresses towards the other end. The front is illuminated by clusters of Acoustic Emissions, and leaves behind a heavily damaged material where the P-wave speed has dropped by up to 20%.The technique opens new possibilities to track in-situ strain localisation and damage around laboratory faults, and preliminary results on quasi-static rupture in granite will be presented.

Development of On-line Wildfire Emissions for the Operational Canadian Air Quality Forecast System

NASA Astrophysics Data System (ADS)

Pavlovic, R.; Menard, S.; Chen, J.; Anselmo, D.; Paul-Andre, B.; Gravel, S.; Moran, M. D.; Davignon, D.

2013-12-01

An emissions processing system has been developed to incorporate near-real-time emissions from wildfires and large prescribed burns into Environment Canada's real-time GEM-MACH air quality (AQ) forecast system. Since the GEM-MACH forecast domain covers Canada and most of the USA, including Alaska, fire location information is needed for both of these large countries. Near-real-time satellite data are obtained and processed separately for the two countries for organizational reasons. Fire location and fuel consumption data for Canada are provided by the Canadian Forest Service's Canadian Wild Fire Information System (CWFIS) while fire location and emissions data for the U.S. are provided by the SMARTFIRE (Satellite Mapping Automated Reanalysis Tool for Fire Incident Reconciliation) system via the on-line BlueSky Gateway. During AQ model runs, emissions from individual fire sources are injected into elevated model layers based on plume-rise calculations and then transport and chemistry calculations are performed. This 'on the fly' approach to the insertion of emissions provides greater flexibility since on-line meteorology is used and reduces computational overhead in emission pre-processing. An experimental wildfire version of GEM-MACH was run in real-time mode for the summers of 2012 and 2013. 48-hour forecasts were generated every 12 hours (at 00 and 12 UTC). Noticeable improvements in the AQ forecasts for PM2.5 were seen in numerous regions where fire activity was high. Case studies evaluating model performance for specific regions, computed objective scores, and subjective evaluations by AQ forecasters will be included in this presentation. Using the lessons learned from the last two summers, Environment Canada will continue to work towards the goal of incorporating near-real-time intermittent wildfire emissions within the operational air quality forecast system.

Fugitive Emissions from the Bakken Shale Illustrate Role of Shale Production in Global Ethane Shift

NASA Technical Reports Server (NTRS)

Kort, E. A.; Smith, M. L.; Murray, L. T.; Gvakharia, A.; Brandt, A. R.; Peischl, J.; Ryerson, T. B.; Sweeney, C.; Travis, K.

2016-01-01

Ethane is the second most abundant atmospheric hydrocarbon, exerts a strong influence on tropospheric ozone, and reduces the atmosphere's oxidative capacity. Global observations showed declining ethane abundances from 1984 to 2010, while a regional measurement indicated increasing levels since 2009, with the reason for this subject to speculation. The Bakken shale is an oil and gas-producing formation centered in North Dakota that experienced a rapid increase in production beginning in 2010. We use airborne data collected over the North Dakota portion of the Bakken shale in 2014 to calculate ethane emissions of 0.23 +/- 0.07 (2 sigma) Tg/yr, equivalent to 1-3% of total global sources. Emissions of this magnitude impact air quality via concurrent increases in tropospheric ozone. This recently developed large ethane source from one location illustrates the key role of shale oil and gas production in rising global ethane levels.

Assessing the effects of transboundary ozone pollution between Ontario, Canada and New York, USA.

PubMed

Brankov, Elvira; Henry, Robert F; Civerolo, Kevin L; Hao, Winston; Rao, S T; Misra, P K; Bloxam, Robert; Reid, Neville

2003-01-01

We investigated the effects of transboundary pollution between Ontario and New York using both observations and modeling results. Analysis of the spatial scales associated with ozone pollution revealed the regional and international character of this pollutant. A back-trajectory-clustering methodology was used to evaluate the potential for transboundary pollution trading and to identify potential pollution source regions for two sites: CN tower in Toronto and the World Trade Center in New York City. Transboundary pollution transport was evident at both locations. The major pollution source areas for the period examined were the Ohio River Valley and Midwest. Finally, we examined the transboundary impact of emission reductions through photochemical models. We found that emissions from both New York and Ontario were transported across the border and that reductions in predicted O3 levels can be substantial when emissions on both sides of the border are reduced.

An optimized inverse modelling method for determining the location and strength of a point source releasing airborne material in urban environment

NASA Astrophysics Data System (ADS)

Efthimiou, George C.; Kovalets, Ivan V.; Venetsanos, Alexandros; Andronopoulos, Spyros; Argyropoulos, Christos D.; Kakosimos, Konstantinos

2017-12-01

An improved inverse modelling method to estimate the location and the emission rate of an unknown point stationary source of passive atmospheric pollutant in a complex urban geometry is incorporated in the Computational Fluid Dynamics code ADREA-HF and presented in this paper. The key improvement in relation to the previous version of the method lies in a two-step segregated approach. At first only the source coordinates are analysed using a correlation function of measured and calculated concentrations. In the second step the source rate is identified by minimizing a quadratic cost function. The validation of the new algorithm is performed by simulating the MUST wind tunnel experiment. A grid-independent flow field solution is firstly attained by applying successive refinements of the computational mesh and the final wind flow is validated against the measurements quantitatively and qualitatively. The old and new versions of the source term estimation method are tested on a coarse and a fine mesh. The new method appeared to be more robust, giving satisfactory estimations of source location and emission rate on both grids. The performance of the old version of the method varied between failure and success and appeared to be sensitive to the selection of model error magnitude that needs to be inserted in its quadratic cost function. The performance of the method depends also on the number and the placement of sensors constituting the measurement network. Of significant interest for the practical application of the method in urban settings is the number of concentration sensors required to obtain a ;satisfactory; determination of the source. The probability of obtaining a satisfactory solution - according to specified criteria -by the new method has been assessed as function of the number of sensors that constitute the measurement network.

A simplified approach to analyze the effectiveness of NO2 and SO2 emission reduction of coal-fired power plant from OMI retrievals

NASA Astrophysics Data System (ADS)

Bai, Yang; Wu, Lixin; Zhou, Yuan; Li, Ding

2017-04-01

Nitrogen oxides (NOX) and sulfur dioxide (SO2) emissions from coal combustion, which is oxidized quickly in the atmosphere resulting in secondary aerosol formation and acid deposition, are the main resource causing China's regional fog-haze pollution. Extensive literature has estimated quantitatively the lifetimes and emissions of NO2 and SO2 for large point sources such as coal-fired power plants and cities using satellite measurements. However, rare of these methods is suitable for sources located in a heterogeneously polluted background. In this work, we present a simplified emission effective radius extraction model for point source to study the NO2 and SO2 reduction trend in China with complex polluted sources. First, to find out the time range during which actual emissions could be derived from satellite observations, the spatial distribution characteristics of mean daily, monthly, seasonal and annual concentration of OMI NO2 and SO2 around a single power plant were analyzed and compared. Then, a 100 km × 100 km geographical grid with a 1 km step was established around the source and the mean concentration of all satellite pixels covered in each grid point is calculated by the area weight pixel-averaging approach. The emission effective radius is defined by the concentration gradient values near the power plant. Finally, the developed model is employed to investigate the characteristic and evolution of NO2 and SO2 emissions and verify the effectiveness of flue gas desulfurization (FGD) and selective catalytic reduction (SCR) devices applied in coal-fired power plants during the period of 10 years from 2006 to 2015. It can be observed that the the spatial distribution pattern of NO2 and SO2 concentration in the vicinity of large coal-burning source was not only affected by the emission of coal-burning itself, but also closely related to the process of pollutant transmission and diffusion caused by meteorological factors in different seasons. Our proposed model can be used to identify the effective operation time of FGD and SCR equipped in coal-fired power plant.

Ultrabroadband phased-array radio frequency (RF) receivers based on optical techniques

NASA Astrophysics Data System (ADS)

Overmiller, Brock M.; Schuetz, Christopher A.; Schneider, Garrett; Murakowski, Janusz; Prather, Dennis W.

2014-03-01

Military operations require the ability to locate and identify electronic emissions in the battlefield environment. However, recent developments in radio detection and ranging (RADAR) and communications technology are making it harder to effectively identify such emissions. Phased array systems aid in discriminating emitters in the scene by virtue of their relatively high-gain beam steering and nulling capabilities. For the purpose of locating emitters, we present an approach realize a broadband receiver based on optical processing techniques applied to the response of detectors in conformal antenna arrays. This approach utilizes photonic techniques that enable us to capture, route, and process the incoming signals. Optical modulators convert the incoming signals up to and exceeding 110 GHz with appreciable conversion efficiency and route these signals via fiber optics to a central processing location. This central processor consists of a closed loop phase control system which compensates for phase fluctuations induced on the fibers due to thermal or acoustic vibrations as well as an optical heterodyne approach for signal conversion down to baseband. Our optical heterodyne approach uses injection-locked paired optical sources to perform heterodyne downconversion/frequency identification of the detected emission. Preliminary geolocation and frequency identification testing of electronic emissions has been performed demonstrating the capabilities of our RF receiver.

Identifiability and identification of trace continuous pollutant source.

PubMed

Qu, Hongquan; Liu, Shouwen; Pang, Liping; Hu, Tao

2014-01-01

Accidental pollution events often threaten people's health and lives, and a pollutant source is very necessary so that prompt remedial actions can be taken. In this paper, a trace continuous pollutant source identification method is developed to identify a sudden continuous emission pollutant source in an enclosed space. The location probability model is set up firstly, and then the identification method is realized by searching a global optimal objective value of the location probability. In order to discuss the identifiability performance of the presented method, a conception of a synergy degree of velocity fields is presented in order to quantitatively analyze the impact of velocity field on the identification performance. Based on this conception, some simulation cases were conducted. The application conditions of this method are obtained according to the simulation studies. In order to verify the presented method, we designed an experiment and identified an unknown source appearing in the experimental space. The result showed that the method can identify a sudden trace continuous source when the studied situation satisfies the application conditions.

137Cs activities and 135Cs/137Cs isotopic ratios from soils at Idaho National Laboratory: a case study for contaminant source attribution in the vicinity of nuclear facilities.

PubMed

Snow, Mathew S; Snyder, Darin C; Clark, Sue B; Kelley, Morgan; Delmore, James E

2015-03-03

Radiometric and mass spectrometric analyses of Cs contamination in the environment can reveal the location of Cs emission sources, release mechanisms, modes of transport, prediction of future contamination migration, and attribution of contamination to specific generator(s) and/or process(es). The Subsurface Disposal Area (SDA) at Idaho National Laboratory (INL) represents a complicated case study for demonstrating the current capabilities and limitations to environmental Cs analyses. (137)Cs distribution patterns, (135)Cs/(137)Cs isotope ratios, known Cs chemistry at this site, and historical records enable narrowing the list of possible emission sources and release events to a single source and event, with the SDA identified as the emission source and flood transport of material from within Pit 9 and Trench 48 as the primary release event. These data combined allow refining the possible number of waste generators from dozens to a single generator, with INL on-site research and reactor programs identified as the most likely waste generator. A discussion on the ultimate limitations to the information that (135)Cs/(137)Cs ratios alone can provide is presented and includes (1) uncertainties in the exact date of the fission event and (2) possibility of mixing between different Cs source terms (including nuclear weapons fallout and a source of interest).

137 Cs Activities and 135 Cs/ 137 Cs Isotopic Ratios from Soils at Idaho National Laboratory: A Case Study for Contaminant Source Attribution in the Vicinity of Nuclear Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snow, Mathew S.; Snyder, Darin C.; Clark, Sue B.

2015-03-03

Radiometric and mass spectrometric analyses of Cs contamination in the environment can reveal the location of Cs emission sources, release mechanisms, modes of transport, prediction of future contamination migration, and attribution of contamination to specific generator(s) and/or process(es). The Subsurface Disposal Area (SDA) at Idaho National Laboratory (INL) represents a complicated case study for demonstrating the current capabilities and limitations to environmental Cs analyses. 137Cs distribution patterns, 135Cs/ 137Cs isotope ratios, known Cs chemistry at this site, and historical records enable narrowing the list of possible emission sources and release events to a single source and event, with the SDAmore » identified as the emission source and flood transport of material from within Pit 9 and Trench 48 as the primary release event. These data combined allow refining the possible number of waste generators from dozens to a single generator, with INL on-site research and reactor programs identified as the most likely waste generator. A discussion on the ultimate limitations to the information that 135Cs/ 137Cs ratios alone can provide is presented and includes (1) uncertainties in the exact date of the fission event and (2) possibility of mixing between different Cs source terms (including nuclear weapons fallout and a source of interest).« less

A regional high-resolution emission inventory of primary air pollutants in 2012 for Beijing and the surrounding five provinces of North China

NASA Astrophysics Data System (ADS)

Liu, Huanjia; Wu, Bobo; Liu, Shuhan; Shao, Panyang; Liu, Xiangyang; Zhu, Chuanyong; Wang, Yong; Wu, Yiming; Xue, Yifeng; Gao, Jiajia; Hao, Yan; Tian, Hezhong

2018-05-01

A high resolution regional emission inventory of typical primary air pollutants (PAPs) for the year 2012 in Beijing and the surrounding five provinces (BSFP) of North China is developed. It is compiled with the combination of bottom-up and top-down methods, based on city-level collected activity data and the latest updated specific emission factors for different sources. The considered sources are classified into 12 major categories and totally 36 subcategories with respect to their multi-dimensional characteristics, such as economic sector, combustion facility or industrial process, installed air pollution control devices, etc. Power plant sector is the dominant contributor of NOX emissions with an average contribution of 34.1%, while VOCs emissions are largely emitted from industrial process sources (33.9%). Whereas, other stationary combustion sources represent major sources of primary PM2.5, PM10 and BC emissions, accounting for 22.7%, 30.0% and 33.9% of the total emissions, respectively. Hebei province contributes over 34% of the regional total CO emissions because of huge volume of iron and steel production. By comparison, Shandong province ranks as the biggest contributor for NOX, PM10, PM2.5, SO2, VOCs and OC. Further, the BSFP regional total emissions are spatially distributed into grid cells with a high resolution of 9 km × 9 km using GIS tools and surrogate indexes, such regional population, gross domestic product (GDP) and the types of arable soils. The highest emission intensities are mainly located in Beijing-Tianjin-Tangshan area, Jinan-Laiwu-Zibo area and several other cities such as Shijiazhuang, Handan, and Zhengzhou. Furthermore, in order to establish a simple method to estimate and forecast PAPs emissions with macroscopic provincial-level statistical parameters in China, multi-parameter regression equations are firstly developed to estimate emissions outside the BSFP region with routine statistics (e.g. population, total final coal consumption, area of cultivated land and possession of civil vehicles) using the software 1stOpt. We find the estimated PAPs emissions of 31 provinces show close correlation with the well-recognized MEIC inventory. This high resolution multi-pollutants inventory provides necessary input data for regional air quality models that could help to identify and appoint the major influence sources, better understand the complex regional air pollution formation mechanism, and benefit for developing the corresponding joint prevention and control policies of regional complex air pollution in North China.

The National Emissions Inventory Significantly Overestimates NOx Emissions: Analysis of CMAQ and in situ observations from DISCOVER-AQ

NASA Astrophysics Data System (ADS)

Anderson, D. C.; Dickerson, R. R.; Loughner, C.

2013-12-01

NOx and CO not only adversely impact human health, but they, along with associated VOCs, are also important precursors for O3 formation. While ambient NOx and CO concentrations have decreased dramatically over the past 10-20 years, O3 has remained a more recalcitrant problem, particularly in the Baltimore/Washington region. Reduction of O3 production requires that emissions inventories, such as the National Emissions Inventory (NEI), accurately capture total emissions of CO and NOx while also correctly apportioning them among different sectors. Previous evaluations of the NEI paint different pictures of its accuracy, with assertions that it overestimates either one or both of CO and NOx from anywhere between 25 percent to a factor of 2. These conflicting claims warrant further investigation. In this study, measurements of NOx and CO taken aboard the NOAA P3B airplane during the 2011 DISCOVER-AQ field campaign were used to determine the NOx/CO emissions ratio at 6 locations in the Washington/Baltimore region. An average molar emissions ratio of 12.8 × 1.2 CO/NOx was found by calculating the change in CO over the change in NOx from vertical concentration profiles in the planetary boundary layer. Ratios showed little variation with location. Observed values were approximately a factor of 1.35 - 1.75 times greater than that predicted by the annual, countywide emissions ratio from the 2008 NEI. When compared to a temporalized, gridded version of the inventory processed by SMOKE, ratio observations were greater than that predicted by inventories by up to a factor of 2. Comparison of the in situ measurements and remotely sensed observations from MOPITT of CO to the Community Multiscale Air Quality (CMAQ) model agree within 10-35 percent, with the model higher on average. Measurements of NOy by two separate analytical techniques, on the other hand, show that CMAQ consistently and significantly overestimates NOy concentrations. Combined with the CO observations, this indicates that the NEI overestimates NOx emissions by approximately a factor of 2. Comparison of the temporalized NEI to continuous monitoring of NOx emissions from point sources shows that, on average, agreement between observations and the NEI were within 5 percent. In a region where the NEI estimates on-road emissions can account for 50-75 percent of total NOx, the most likely source of error in the NOx inventory is in the on-road sector. Assumptions about the lifetime and efficacy of catalytic converters in the MOVES model should be investigated as a possible source of this error.

Spatial patterns of mobile source particulate matter emissions-to-exposure relationships across the United States

NASA Astrophysics Data System (ADS)

Greco, Susan L.; Wilson, Andrew M.; Spengler, John D.; Levy, Jonathan I.

Assessing the public health benefits from air pollution control measures is assisted by understanding the relationship between mobile source emissions and subsequent fine particulate matter (PM 2.5) exposure. Since this relationship varies by location, we characterized its magnitude and geographic distribution using the intake fraction (iF) concept. We considered emissions of primary PM 2.5 as well as particle precursors SO 2 and NO x from each of 3080 counties in the US. We modeled the relationship between these emissions and total US population exposure to PM 2.5, making use of a source-receptor matrix developed for health risk assessment. For primary PM 2.5, we found a median iF of 1.2 per million, with a range of 0.12-25. Half of the total exposure was reached by a median distance of 150 km from the county where mobile source emissions originated, though this spatial extent varied across counties from within the county borders to 1800 km away. For secondary ammonium sulfate from SO 2 emissions, the median iF was 0.41 per million (range: 0.050-10), versus 0.068 per million for secondary ammonium nitrate from NO x emissions (range: 0.00092-1.3). The median distance to half of the total exposure was greater for secondary PM 2.5 (450 km for sulfate, 390 km for nitrate). Regression analyses using exhaustive population predictors explained much of the variation in primary PM 2.5 iF ( R2=0.83) as well as secondary sulfate and nitrate iF ( R2=0.74 and 0.60), with greater near-source contribution for primary than for secondary PM 2.5. We conclude that long-range dispersion models with coarse geographic resolution are appropriate for risk assessments of secondary PM 2.5 or primary PM 2.5 emitted from mobile sources in rural areas, but that more resolved dispersion models are warranted for primary PM 2.5 in urban areas due to the substantial contribution of near-source populations.

Outflow structure and velocity field of Orion source. I. ALMA imaging of SiO isotopologue maser and thermal emission

NASA Astrophysics Data System (ADS)

Niederhofer, F.; Humphreys, E. M. L.; Goddi, C.

2012-12-01

Using Science Verification data from the Atacama Large Millimeter/Submillimeter Array (ALMA), we have identified and imaged five rotational transitions (J = 5-4 and J = 6-5) of the three silicon monoxide isotopologues 28SiO v = 0, 1, 2 and 29SiO v = 0 and 28Si18O v = 0 in the frequency range from 214 to 246 GHz towards the Orion BN/KL region. The emission of the ground-state 28SiO, 29SiO and 28Si18O shows an extended bipolar shape in the northeast-southwest direction at the position of Radio Source I, indicating that these isotopologues trace an outflow ( 18 km s-1, PA 50°, 5000 AU in diameter) that is driven by this embedded high-mass young stellar object (YSO). Whereas on small scales (10-1000 AU) the outflow from Source I has a well-ordered spatial and velocity structure, as probed by Very Long Baseline Interferometry (VLBI) imaging of SiO masers, the large scales (500-5000 AU) probed by thermal SiO with ALMA reveal a complex structure and velocity field, most likely related to the effects of the environment of the BN/KL region on the outflow emanating from Source I. The emission of the vibrationally-excited species peaks at the position of Source I. This emission is compact and not resolved at an angular resolution of 1farcs5 ( 600 AU at a distance of 420 pc). 2D Gaussian fitting to individual velocity channels locates emission peaks within radii of 100 AU, i.e. they trace the innermost part of the outflow. A narrow spectral profile and spatial distribution of the v = 1 J = 5-4 line similar to the masing v = 1 J = 1-0 transition, provide evidence for the most highly rotationally excited (frequency > 200 GHz) SiO maser emission associated with Source I known to date. The maser emission will enable studies of the Source I disk-outflow interface with future ALMA longest baselines.

The Water Maser in II Zw 96: Scientific Justification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiggins, Brandon Kerry

We propose a VLBI search to image and locate the water emission in II Zw 96. We propose 3 sites within II Zw 96 for VLBI followup (see the proposed target listing below). We request 2.5 hours of on-source integration time with the VLBA per source. The array will achieve ~ 65µJy sensitivity in K band in this time which will be sufficient to detect luminous water maser features.

Impact of emissions from natural gas production facilities on ambient air quality in the Barnett Shale area: a pilot study.

PubMed

Zielinska, Barbara; Campbell, Dave; Samburova, Vera

2014-12-01

Rapid and extensive development of shale gas resources in the Barnett Shale region of Texas in recent years has created concerns about potential environmental impacts on water and air quality. The purpose of this study was to provide a better understanding of the potential contributions of emissions from gas production operations to population exposure to air toxics in the Barnett Shale region. This goal was approached using a combination of chemical characterization of the volatile organic compound (VOC) emissions from active wells, saturation monitoring for gaseous and particulate pollutants in a residential community located near active gas/oil extraction and processing facilities, source apportionment of VOCs measured in the community using the Chemical Mass Balance (CMB) receptor model, and direct measurements of the pollutant gradient downwind of a gas well with high VOC emissions. Overall, the study results indicate that air quality impacts due to individual gas wells and compressor stations are not likely to be discernible beyond a distance of approximately 100 m in the downwind direction. However, source apportionment results indicate a significant contribution to regional VOCs from gas production sources, particularly for lower-molecular-weight alkanes (< C6). Although measured ambient VOC concentrations were well below health-based safe exposure levels, the existence of urban-level mean concentrations of benzene and other mobile source air toxics combined with soot to total carbon ratios that were high for an area with little residential or commercial development may be indicative of the impact of increased heavy-duty vehicle traffic related to gas production. Implications: Rapid and extensive development of shale gas resources in recent years has created concerns about potential environmental impacts on water and air quality. This study focused on directly measuring the ambient air pollutant levels occurring at residential properties located near natural gas extraction and processing facilities, and estimating the relative contributions from gas production and motor vehicle emissions to ambient VOC concentrations. Although only a small-scale case study, the results may be useful for guidance in planning future ambient air quality studies and human exposure estimates in areas of intensive shale gas production.

Quantifying point source emissions with atmospheric inversions and aircraft measurements: the Aliso Canyon natural gas leak as a tracer experiment

NASA Astrophysics Data System (ADS)

Gourdji, S.; Yadav, V.; Karion, A.; Mueller, K. L.; Kort, E. A.; Conley, S.; Ryerson, T. B.; Nehrkorn, T.

2017-12-01

The ability of atmospheric inverse models to detect, spatially locate and quantify emissions from large point sources in urban domains needs improvement before inversions can be used reliably as carbon monitoring tools. In this study, we use the Aliso Canyon natural gas leak from October 2015 to February 2016 (near Los Angeles, CA) as a natural tracer experiment to assess inversion quality by comparison with published estimates of leak rates calculated using a mass balance approach (Conley et al., 2016). Fourteen dedicated flights were flown in horizontal transects downwind and throughout the duration of the leak to sample CH4 mole fractions and collect meteorological information for use in the mass-balance estimates. The same CH4 observational data were then used here in geostatistical inverse models with no prior assumptions about the leak location or emission rate and flux sensitivity matrices generated using the WRF-STILT atmospheric transport model. Transport model errors were assessed by comparing WRF-STILT wind speeds, wind direction and planetary boundary layer (PBL) height to those observed on the plane; the impact of these errors in the inversions, and the optimal inversion setup for reducing their influence was also explored. WRF-STILT provides a reasonable simulation of true atmospheric conditions on most flight dates, given the complex terrain and known difficulties in simulating atmospheric transport under such conditions. Moreover, even large (>120°) errors in wind direction were found to be tolerable in terms of spatially locating the leak rate within a 5-km radius of the actual site. Errors in the WRF-STILT wind speed (>50%) and PBL height have more negative impacts on the inversions, with too high wind speeds (typically corresponding with too low PBL heights) resulting in overestimated leak rates, and vice-versa. Coarser data averaging intervals and the use of observed wind speed errors in the model-data mismatch covariance matrix are shown to help reduce the influence of transport model errors, by averaging out compensating errors and de-weighting the influence of problematic observations. This study helps to enable the integration of aircraft measurements with other tower-based data in larger inverse models that can reliably detect, locate and quantify point source emissions in urban areas.

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Chemical Preparations... methods described in paragraphs (a), (b) or (c) of this section while equipment within a chemical... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position...

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Chemical Preparations... methods described in paragraphs (a), (b) or (c) of this section while equipment within a chemical... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position...

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Area Sources: Chemical Preparations... methods described in paragraphs (a), (b) or (c) of this section while equipment within a chemical... applicable, and the following: (1) Locate the pressure sensor(s) in, or as close as possible to, a position...

40 CFR 63.1432 - Storage vessel provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Storage vessel provisions. 63.1432... Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63.1432 Storage vessel provisions. (a) For each storage vessel located at an affected source, the owner or operator shall comply...

40 CFR 63.1432 - Storage vessel provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Storage vessel provisions. 63.1432... Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63.1432 Storage vessel provisions. (a) For each storage vessel located at an affected source, the owner or operator shall comply...

Characterizing and sourcing ambient PM2.5 over key emission regions in China III: Carbon isotope based source apportionment of black carbon

NASA Astrophysics Data System (ADS)

Yu, Kuangyou; Xing, Zhenyu; Huang, Xiaofeng; Deng, Junjun; Andersson, August; Fang, Wenzheng; Gustafsson, Örjan; Zhou, Jiabin; Du, Ke

2018-03-01

Regional haze over China has severe implications for air quality and regional climate. To effectively combat these effects the high uncertainties regarding the emissions from different sources needs to be reduced. In this paper, which is the third in a series on the sources of PM2.5 in pollution hotspot regions of China, we focus on the sources of black carbon aerosols (BC), using carbon isotope signatures. Four-season samples were collected at two key locations: Beijing-Tianjin-Hebei (BTH, part of Northern China plain), and the Pearl River Delta (PRD). We find that that fossil fuel combustion was the predominant source of BC in both BTH and PRD regions, accounting for 75 ± 5%. However, the contributions of what fossil fuel components were dominating differed significantly between BTH and PRD, and varied dramatically with seasons. Coal combustion is overall the all-important BC source in BTH, accounting for 46 ± 12% of the BC in BTH, with the maximum value (62%) found in winter. In contrast for the PRD region, liquid fossil fuel combustion (e.g., oil, diesel, and gasoline) is the dominant source of BC, with an annual mean value of 41 ± 15% and the maximum value of 55% found in winter. Region- and season-specific source apportionments are recommended to both accurately assess the climate impact of carbonaceous aerosol emissions and to effectively mitigate deteriorating air quality caused by carbonaceous aerosols.

Parametric uncertainties in global model simulations of black carbon column mass concentration

NASA Astrophysics Data System (ADS)

Pearce, Hana; Lee, Lindsay; Reddington, Carly; Carslaw, Ken; Mann, Graham

2016-04-01

Previous studies have deduced that the annual mean direct radiative forcing from black carbon (BC) aerosol may regionally be up to 5 W m-2 larger than expected due to underestimation of global atmospheric BC absorption in models. We have identified the magnitude and important sources of parametric uncertainty in simulations of BC column mass concentration from a global aerosol microphysics model (GLOMAP-Mode). A variance-based uncertainty analysis of 28 parameters has been performed, based on statistical emulators trained on model output from GLOMAP-Mode. This is the largest number of uncertain model parameters to be considered in a BC uncertainty analysis to date and covers primary aerosol emissions, microphysical processes and structural parameters related to the aerosol size distribution. We will present several recommendations for further research to improve the fidelity of simulated BC. In brief, we find that the standard deviation around the simulated mean annual BC column mass concentration varies globally between 2.5 x 10-9 g cm-2 in remote marine regions and 1.25 x 10-6 g cm-2 near emission sources due to parameter uncertainty Between 60 and 90% of the variance over source regions is due to uncertainty associated with primary BC emission fluxes, including biomass burning, fossil fuel and biofuel emissions. While the contributions to BC column uncertainty from microphysical processes, for example those related to dry and wet deposition, are increased over remote regions, we find that emissions still make an important contribution in these areas. It is likely, however, that the importance of structural model error, i.e. differences between models, is greater than parametric uncertainty. We have extended our analysis to emulate vertical BC profiles at several locations in the mid-Pacific Ocean and identify the parameters contributing to uncertainty in the vertical distribution of black carbon at these locations. We will present preliminary comparisons of emulated BC vertical profiles from the AeroCom multi-model ensemble and Hiaper Pole-to-Pole (HIPPO) observations.

Do oceanic emissions account for the missing source of atmospheric carbonyl sulfide?

NASA Astrophysics Data System (ADS)

Lennartz, Sinikka; Marandino, Christa A.; von Hobe, Marc; Cortés, Pau; Simó, Rafel; Booge, Dennis; Quack, Birgit; Röttgers, Rüdiger; Ksionzek, Kerstin; Koch, Boris P.; Bracher, Astrid; Krüger, Kirstin

2016-04-01

Carbonyl sulfide (OCS) has a large potential to constrain terrestrial gross primary production (GPP), one of the largest carbon fluxes in the carbon cycle, as it is taken up by plants in a similar way as CO2. To estimate GPP in a global approach, the magnitude and seasonality of sources and sinks of atmospheric OCS have to be well understood, to distinguish between seasonal variation caused by vegetation uptake and other sources or sinks. However, the atmospheric budget is currently highly uncertain, and especially the oceanic source strength is debated. Recent studies suggest that a missing source of several hundreds of Gg sulfur per year is located in the tropical ocean by a top-down approach. Here, we present highly-resolved OCS measurements from two cruises to the tropical Pacific and Indian Ocean as a bottom-up approach. The results from these cruises show that opposite to the assumed ocean source, direct emissions of OCS from the tropical ocean are unlikely to account for the missing source. To reduce uncertainty in the global oceanic emission estimate, our understanding of the production and consumption processes of OCS and its precursors, dimethylsulfide (DMS) and carbon disulphide (CS2), needs improvement. Therefore, we investigate the influence of dissolved organic matter (DOM) on the photochemical production of OCS in seawater by considering analysis of the composition of DOM from the two cruises. Additionally, we discuss the potential of oceanic emissions of DMS and CS2 to closing the atmospheric OCS budget. Especially the production and consumption processes of CS2 in the surface ocean are not well known, thus we evaluate possible photochemical or biological sources by analyzing its covariation of biological and photochemical parameters.

Chemical speciation and source apportionment of Non-Methane Volatile Organic Compounds (NMVOCs) in a Middle Eastern country

NASA Astrophysics Data System (ADS)

Salameh, Therese; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

2014-05-01

NMVOCs, emitted from various sources, are of particular interest since they contribute to the formation of tropospheric ozone, PAN and secondary organic aerosols resulting in negative impacts on human health, climate and on the environment. To identify abatement measures, a profound knowledge of emission sources and their composition is a prerequisite. Air pollution in the Middle East region remains difficult to assess and understand because of a lack of ground-based measurements and the limited information on NMVOC chemical speciation and source apportionment. Based on a large database of NMVOC observations obtained in Beirut, the capital of Lebanon (a developing country in the Middle East region, located in Western Asia on the eastern shore of the Mediterranean Sea), the overall objective of this work is to apportion the sources of NMVOCs encountered in Lebanon. First, source profiles were determined with field measurements close to the main potential emitters namely the road transport, gasoline vapour, power generation and solvent uses. The results obtained are compared to other studies held in other regions and are used to assess the emission inventory developed for Lebanon. Secondly, two intensive field campaigns were held in a receptor site in Beirut during summer 2011 and winter 2012 in order to obtain a large time resolved dataset. The PMF analysis of this dataset was applied to apportion anthropogenic sources in this area. In both seasons, combustion (road transport and power generation) and gasoline evaporation, especially in winter, were the main sources contributing to the NMVOCs in Beirut. The results will support model implementation especially by completing the emission inventory established for the year 2010 by Waked et al. 2012 according to the EEA/EMEP guidelines because of the lack of Lebanon-specific emission factor.

Characterization of Extractable Organic Fine Particulate Matter in the Atmosphere of Houston and Source Apportionment Calculations Using Organic Molecular Markers

NASA Astrophysics Data System (ADS)

Fraser, M. P.; Yue, Z. W.; Buzco, B.

2002-12-01

Samples of atmospheric PM2.5 were collected in Houston, TX every second day during the summer of 2000 as part of the EPA sponsored Houston Fine Particle Matter Supersite program. Sampling occurred at three sites, including one industrial location (HRM-3), one suburban location (Aldine) and one coastal location (La Porte). Twenty samples collected over a 24 hour period have been analyzed to quantify the concentration of 95 individual organic compounds, including: n-alkanes (C20 to C36), aromatic hydrocarbons (PAHs), n-alkanoic acids (C5 to C34), n-alkenoic acids (C18:1 and C18:2), carboxylic diacids (C3 to C10), petroleum biomarkers and others. As a whole, the extractable compounds were dominated by acids, especially by octadecanoic acid and hexadecanoic acid. The measured concentration of n-alkanes exhibited a peak at C29, with carbon preference index (CPI) values in the range of 0.97 to 2.0. Using organic molecular markers, including seven alkanes, four petroleum biomarkers, seven PAH, one alkanoic acid, one alkenoic acid, levoglucosan, and three chemical components (Al, Si and Elemental Carbon), Chemical Mass Balancing (CMB) calculations have been performed on the ambient speciation data. These calculations are used to determine the contribution of seven different primary emission sources including: diesel powered vehicles, gasoline vehicles, wood combustion, fuel oil combustion, road dusts, meat cooking and vegetation waxes. The contribution of diesel powered vehicles and gasoline powered vehicles are the most important primary sources at all three sampling locations, with road dusts important at the industrial location. Meat cooking emissions were significant at all three locations. Wood combustion is an important contribution during a four-day period when uncontrolled wildfires in eastern Texas and Louisiana brought biomass combustion aerosols into the sampling region.

Quantifying the relative contribution of natural gas fugitive emissions to total methane emissions in Weld County Colorado using δ13CH4 analysis

NASA Astrophysics Data System (ADS)

Rella, C.; Jacobson, G. A.; Crosson, E.; Sweeney, C.; Karion, A.; Petron, G.

2012-12-01

Fugitive emissions of methane into the atmosphere are a major concern facing the natural gas production industry. Given that the global warming potential of methane is many times greater than that of carbon dioxide (Forster et al. 2007), the importance of quantifying methane emissions becomes clear. Companion presentations at this meeting describe efforts to quantify the overall methane emissions in two separate gas producing areas in Colorado and Utah during intensive field campaigns undertaken in 2012. A key step in the process of assessing the emissions arising from natural gas production activities is partitioning the observed methane emissions between natural gas fugitive emissions and other sources of methane, such as from landfills or agricultural activities. One method for assessing the contribution of these different sources is stable isotope analysis. In particular, the δ13CH4 signature of natural gas (-37 permil) is significantly different that the signature of other significant sources of methane, such as landfills or ruminants (-50 to -70 permil). In this paper we present measurements of δ13CH4 in Colorado in Weld County, a region of intense natural gas production, using a mobile δ13CH4¬ analyzer capable of high-precision measurements of the stable isotope ratio of methane at ambient levels. This analyzer was used to make stable isotope measurements at a fixed location near the center of the gas producing region, from which an overall isotope ratio for the regional emissions is determined. In addition, mobile measurements in the nocturnal boundary layer have been made, over a total distance of 150 km throughout Weld County, allowing spatially resolved measurements of this isotope signature. Finally, this analyzer was used to quantify the isotopic signature of those individual sources (natural gas fugitive emissions, concentrated animal feeding operations, and landfills) that constitute the majority of methane emissions in this region, by making measurements of the isotope ratio directly in the downwind plume from each source. These data are combined to establish the fraction of the observed methane emissions that can be attributed to natural gas activities in the region. The results are compared to inventories as well as other measurement techniques, and the uncertainty of the measurement is estimated.

A New Method of Using Sensor Arrays for Gas Leakage Location Based on Correlation of the Time-Space Domain of Continuous Ultrasound

PubMed Central

Bian, Xu; Zhang, Yu; Li, Yibo; Gong, Xiaoyue; Jin, Shijiu

2015-01-01

This paper proposes a time-space domain correlation-based method for gas leakage detection and location. It acquires the propagated signal on the skin of the plate by using a piezoelectric acoustic emission (AE) sensor array. The signal generated from the gas leakage hole (which diameter is less than 2 mm) is time continuous. By collecting and analyzing signals from different sensors’ positions in the array, the correlation among those signals in the time-space domain can be achieved. Then, the directional relationship between the sensor array and the leakage source can be calculated. The method successfully solves the real-time orientation problem of continuous ultrasonic signals generated from leakage sources (the orientation time is about 15 s once), and acquires high accuracy location information of leakage sources by the combination of multiple sets of orientation results. According to the experimental results, the mean value of the location absolute error is 5.83 mm on a one square meter plate, and the maximum location error is generally within a ±10 mm interval. Meanwhile, the error variance is less than 20.17. PMID:25860070

A new method of using sensor arrays for gas leakage location based on correlation of the time-space domain of continuous ultrasound.

PubMed

Bian, Xu; Zhang, Yu; Li, Yibo; Gong, Xiaoyue; Jin, Shijiu

2015-04-09

This paper proposes a time-space domain correlation-based method for gas leakage detection and location. It acquires the propagated signal on the skin of the plate by using a piezoelectric acoustic emission (AE) sensor array. The signal generated from the gas leakage hole (which diameter is less than 2 mm) is time continuous. By collecting and analyzing signals from different sensors' positions in the array, the correlation among those signals in the time-space domain can be achieved. Then, the directional relationship between the sensor array and the leakage source can be calculated. The method successfully solves the real-time orientation problem of continuous ultrasonic signals generated from leakage sources (the orientation time is about 15 s once), and acquires high accuracy location information of leakage sources by the combination of multiple sets of orientation results. According to the experimental results, the mean value of the location absolute error is 5.83 mm on a one square meter plate, and the maximum location error is generally within a ±10 mm interval. Meanwhile, the error variance is less than 20.17.

Locating single-point sources from arrival times containing large picking errors (LPEs): the virtual field optimization method (VFOM)

NASA Astrophysics Data System (ADS)

Li, Xi-Bing; Wang, Ze-Wei; Dong, Long-Jun

2016-01-01

Microseismic monitoring systems using local location techniques tend to be timely, automatic and stable. One basic requirement of these systems is the automatic picking of arrival times. However, arrival times generated by automated techniques always contain large picking errors (LPEs), which may make the location solution unreliable and cause the integrated system to be unstable. To overcome the LPE issue, we propose the virtual field optimization method (VFOM) for locating single-point sources. In contrast to existing approaches, the VFOM optimizes a continuous and virtually established objective function to search the space for the common intersection of the hyperboloids, which is determined by sensor pairs other than the least residual between the model-calculated and measured arrivals. The results of numerical examples and in-site blasts show that the VFOM can obtain more precise and stable solutions than traditional methods when the input data contain LPEs. Furthermore, we discuss the impact of LPEs on objective functions to determine the LPE-tolerant mechanism, velocity sensitivity and stopping criteria of the VFOM. The proposed method is also capable of locating acoustic sources using passive techniques such as passive sonar detection and acoustic emission.

Methane emissions measurements of natural gas components using a utility terrain vehicle and portable methane quantification system

NASA Astrophysics Data System (ADS)

Johnson, Derek; Heltzel, Robert

2016-11-01

Greenhouse Gas (GHG) emissions are a growing problem in the United States (US). Methane (CH4) is a potent GHG produced by several stages of the natural gas sector. Current scrutiny focuses on the natural gas boom associated with unconventional shale gas; however, focus should still be given to conventional wells and outdated equipment. In an attempt to quantify these emissions, researchers modified an off-road utility terrain vehicle (UTV) to include a Full Flow Sampling system (FFS) for methane quantification. GHG emissions were measured from non-producing and remote low throughput natural gas components in the Marcellus region. Site audits were conducted at eleven locations and leaks were identified and quantified at seven locations including at a low throughput conventional gas and oil well, two out-of-service gathering compressors, a conventional natural gas well, a coalbed methane well, and two conventional and operating gathering compressors. No leaks were detected at the four remaining sites, all of which were coal bed methane wells. The total methane emissions rate from all sources measured was 5.3 ± 0.23 kg/hr, at a minimum.

Continuous emission monitoring and accounting automated systems at an HPP

NASA Astrophysics Data System (ADS)

Roslyakov, P. V.; Ionkin, I. L.; Kondrateva, O. E.; Borovkova, A. M.; Seregin, V. A.; Morozov, I. V.

2015-03-01

Environmental and industrial emission monitoring at HPP's is a very urgent task today. Industrial monitoring assumes monitoring of emissions of harmful pollutants and optimization of fuel combustion technological processes at HPP's. Environmental monitoring is a system to assess ambient air quality with respect to a number of separate sources of harmful substances in pollution of atmospheric air of the area. Works on creating an industrial monitoring system are carried out at the National Research University Moscow Power Engineering Institute (MPEI) on the basis of the MPEI combined heat and power plant, and environmental monitoring stations are installed in Lefortovo raion, where the CHPP is located.

Signatures of solar wind latitudinal structure in interplanetary Lyman-alpha emissions - Mariner 10 observations

NASA Technical Reports Server (NTRS)

Kumar, S.; Broadfoot, A. L.

1979-01-01

A detailed analysis is conducted which shows that signatures in the interplanetary Lyman-alpha emissions observed in three different data sets from Mariner 10 (corresponding to different locations of the spacecraft) provide firm evidence that the intensity departures are correlated with a decrease in solar wind flux with increasing latitude. It is suggested that observations of the interplanetary emission can be used to monitor average solar wind activity at high latitudes. The asymmetry in the solar radiation field as a source of observed departures in L-alpha data is considered and attention is given to the interstellar hydrogen and helium density.

Gridded emission inventory of short-chain chlorinated paraffins and its validation in China.

PubMed

Jiang, Wanyanhan; Huang, Tao; Mao, Xiaoxuan; Wang, Li; Zhao, Yuan; Jia, Chenhui; Wang, Yanan; Gao, Hong; Ma, Jianmin

2017-01-01

China produces approximately 20%-30% of the total global chlorinated paraffins (CPs). The establishment of a short-chain CP (SCCP) emission inventory is a significant step toward risk assessment and regulation of SCCPs in China and throughout the globe. This study developed a gridded SCCPs emission inventory with a 1/4° longitude by 1/4° latitude resolution from 2008 to 2012 for China, which was based on the total annual CPs emissions for the nation. The total national SCCPs emission during this 5-year period was 5651.5 tons. An additive in metal cutting fluids was a major emission source in China, contributing 2680.2 tons to the total atmospheric emissions of SCCPs from 2008 to 2012, followed by the production of CPs (2281.8 tons), plasticizers (514.3 tons), flame retardants (108.6 tons), and net import (66.6 tons). Most of these emission sources are located along the eastern seaboard of China and southern China. A coupled atmospheric transport model was employed to simulate environmental contamination by SCCPs using the gridded emission inventory of SCCPs from 2008 to 2012 as the model initial conditions. Simulated atmospheric and soil concentrations were compared with field monitoring data to validate the emission inventory. The results showed good consistency between modeled and field sampling data, supporting the reliability and credibility of the gridded SCCPs emission inventory that was developed in the present study. Copyright © 2016 Elsevier Ltd. All rights reserved.

Emissions of particulate and gaseous pollutants within the Keelung Harbor region of Taiwan.

PubMed

Yu-Peng, Chiung; Lin, Chern-Gyuan; Jong, Tain-Chyuan

2005-10-01

The Keelung port, which is located on the northern tip of Taiwan, right next to the Taipei metropolitan area, is an important international harbor. However, any air pollutants generated from the Keelung port region, immediately travel to the neighboring Keelung city, and greatly impact the residents' daily life and the quality of their environment. This study has investigated and quantified pollution emissions, from the Keelung port region, between 1997 and 2002. Emissions from major air pollution sources were estimated. The estimated results indicated that total TSP (total suspended particles) emissions had significantly increased, from 5221 ton/yr in 1997 to 262 687 ton/yr in 2002, due to the greatly increased volume of sand imported into Keelung Harbor. Quantities of other emissions, such as SO(2), NO(2), CO and HC remained stable and were 440, 207, 78 and 25 ton/yr, respectively, on average, with variations within 7% over the previous six-year period. By examining the emissions from pollution sources, it was found that TSP emissions mainly originated from re-suspension of dust, due to both vehicle movement and the sand unloading process; this accounted for over 99% of the total TSP emissions produced in the port region. About 80% of the total SO(2) emissions originated from the main ships' engines within the Keelung port region, due to the use of fuel with a high sulfur content. In addition, loading/unloading machines within the port region were the major sources of NO(2), CO and HC pollution emissions, which comprised 54, 58 and 66% of the total emissions of these pollutants, respectively. TSP emissions from Keelung port were much higher than from the neighboring Keelung city; hence, alleviating TSP emissions should be the first priority for air pollution reduction within both the port of Keelung and Keelung city.

Spatially Resolving the Very High Energy Emission from MGRO J2019+37 with VERITAS

NASA Astrophysics Data System (ADS)

Aliu, E.; Aune, T.; Behera, B.; Beilicke, M.; Benbow, W.; Berger, K.; Bird, R.; Bouvier, A.; Buckley, J. H.; Bugaev, V.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dumm, J.; Dwarkadas, V. V.; Errando, M.; Falcone, A.; Federici, S.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Fortin, P.; Fortson, L.; Furniss, A.; Galante, N.; Gillanders, G. H.; Gotthelf, E. V.; Griffin, S.; Griffiths, S. T.; Grube, J.; Gyuk, G.; Hanna, D.; Holder, J.; Hughes, G.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kargaltsev, O.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krennrich, F.; Lang, M. J.; Madhavan, A. S.; Maier, G.; McArthur, S.; McCann, A.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nieto, D.; O'Faoláin de Bhróithe, A.; Ong, R. A.; Otte, A. N.; Pandel, D.; Park, N.; Pohl, M.; Popkow, A.; Prokoph, H.; Quinn, J.; Ragan, K.; Rajotte, J.; Reyes, L. C.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Roberts, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Vincent, S.; Wakely, S. P.; Weinstein, A.; Welsing, R.; Wilhelm, A.; Williams, D. A.; Zitzer, B.

2014-06-01

We present very high energy (VHE) imaging of MGRO J2019+37 obtained with the VERITAS observatory. The bright extended (~2°) unidentified Milagro source is located toward the rich star formation region Cygnus-X. MGRO J2019+37 is resolved into two VERITAS sources. The faint, point-like source VER J2016+371 overlaps CTB 87, a filled-center remnant (SNR) with no evidence of a supernova remnant shell at the present time. Its spectrum is well fit in the 0.65-10 TeV energy range by a power-law model with photon index 2.3 ± 0.4. VER J2019+378 is a bright extended (~1°) source that likely accounts for the bulk of the Milagro emission and is notably coincident with PSR J2021+3651 and the star formation region Sh 2-104. Its spectrum in the range 1-30 TeV is well fit with a power-law model of photon index 1.75 ± 0.3, among the hardest values measured in the VHE band, comparable to that observed near Vela-X. We explore the unusual spectrum and morphology in the radio and X-ray bands to constrain possible emission mechanisms for this source.

Sources of methane and nitrous oxide in California's Central Valley estimated through direct airborne flux and positive matrix factorization source apportionment of groundbased and regional tall tower measurements

NASA Astrophysics Data System (ADS)

Guha, Abhinav

Methane (CH4) and nitrous oxide (N2O) are two major greenhouse gases that contribute significantly to the increase in anthropogenic radiative-forcing causing perturbations to the earth's climate system. In a watershed moment in the state's history of environmental leadership and commitment, California, in 2006, opted for sharp reductions in their greenhouse gas (GHG) emissions and adopted a long-term approach to address climate change that includes regulation of emissions from individual emitters and source categories. There are large CH4 and N2O emissions sources in the state, predominantly in the agricultural and waste management sector. While these two gases account for < 10% of total annual greenhouse gas emissions of the state, large uncertainties exist in their `bottom-up' accounting in the state GHG inventory. Additionally, an increasing number of `top-down' studies based on ambient observations point towards underestimation of their emissions in the inventory. Three intensive field observation campaigns that were spatially and temporally diverse took place between 2010 and 2013 in the Central Valley of California where the largest known sources of CH4 and N2O (e.g. agricultural systems and dairies) and potentially significant CH4 sources (e.g. oil and gas extraction) are located. The CalNex (California Nexus - Research at the Nexus of Air Quality and Climate Change) field campaign during summer 2010 (May 15 - June 30) took place in the urban core of Bakersfield in the southern San Joaquin Valley, a city whose economy is built around agriculture and the oil and gas industry. During summer of 2011, airborne measurements were performed over a large spatial domain, all across and around the Central Valley as part of the CABERNET (California Airborne BVOC Emission Research in Natural Ecosystem Transects) study. Next, a one-year continuous field campaign (WGC 2012-13, June 2012 - August 2013) was conducted at the Walnut Grove tall tower near the Sacramento-San Joaquin River Delta in the Central Valley. Through analysis of these field measurements, this dissertation presents the apportionment of observed CH4 and N2O concentration enhancements into major source categories along with direct emissions estimates from airborne observations. We perform high-precision measurements of greenhouse gases using gas analyzers based on absorption spectroscopy, and other source marker volatile organic compounds (VOCs) using state of the art VOC measurement systems (e.g. proton transfer reaction mass spectrometry). We combine these measurements with a statistical source apportionment technique called positive matrix factorization (PMF) to evaluate and investigate the major local sources of CH4 and N2O during CalNex and Walnut Grove campaigns. In the CABERNET study, we combine measurements with an airborne approach to a well-established micrometeorological technique (eddy-covariance method) to derive CH4 fluxes over different source regions in the Central Valley. In the CalNex experiments, we demonstrate that dairy and livestock remains the largest source sector of non-CO2 greenhouse gases in the San Joaquin Valley contributing most of the CH4 and much of the measured N2O at Bakersfield. Agriculture is observed to provide another major source of N2O, while vehicle emissions are found to be an insignificant source of N2O, contrary to the current statewide greenhouse gas inventory which includes vehicles as a major source. Our PMF source apportionment also produces an evaporative/fugitive factor but its relative lack of CH4 contributions points to removal processes from vented emissions in the surrounding O&G industry and the overwhelming dominance of the dairy CH4 source. In the CABERNET experiments, we report enhancements of CH4 from a number of sources spread across the spatial domain of the Central Valley that improves our understanding of their distribution and relative strengths. We observe large enhancements of CH4 mixing ratios over the dairy and feedlot intensive regions of Central Valley corresponding with significant flux estimates that are larger than CH4 emission rates reported in the greenhouse gas inventory. We find evidence of significant CH 4 emissions from fugitive and/or vented sources and cogeneration plants in the oil and gas fields of Kern County, all of which are minor to insignificant CH4 sources in the current greenhouse gas inventory. The CABERNET campaign represents the first successful implementation of airborne eddy covariance technique for CH4 flux measurements. At Walnut Grove, we demonstrate the seasonal and temporal dependence of CH4 and N2O sources in the Central Valley. Applying PMF analysis on seasonal GHG-VOC data sets, we again identify dairies and livestock as the dominant source of CH4. A clear temporal dependence of emissions originating from a wetlands / Delta CH4 source is observed while CH4 contributions are also observed from a source originating from upwind urban and natural gas extraction activities. The agricultural soil management source of N2O has a seasonal dependence coincident with the agricultural growing season (and hence, fertilizer use) accounting for a majority of the N2O enhancements during spring and summers but being reduced to a negligible source during late fall and winters when manure management N2O emissions from dairy and livestock dominate the relative distribution. N2O is absent from the 'urban' source, in contrast to the significant contribution to the statewide N2O inventory from vehicle emissions. The application of greenhouse gas source apportionment using VOC tracers as identification tools at two independent sites in the Central Valley over vastly different temporal resolutions provide significant insights into the regional distribution of major CH4 sources. Direct airborne eddy covariance measurements provide a unique opportunity to constrain CH 4 emissions in the Central Valley over regional spatial scales that are not directly observable by ground-based methods. Airborne observations provide identification of 'hotspots' and under-inventoried CH4 sources, while airborne eddy covariance enables quantification of emissions from those area sources that are largely composed of arbitrarily located minor point sources (e.g. dairies and oil fields). The top-down analysis provides confirmation of the dominance of dairy and livestock source for methane emissions in California. Minor but significant contributions to methane emissions are observed from oil and gas extraction, rice cultivation and wetlands; the estimates for these sectors being either negligible (e.g. wetlands) or highly uncertain (e.g. oil and gas extraction) in the statewide inventories and probably underestimated as a proportion of the total inventory. The top-down analysis also confirms agricultural soil management and dairy and livestock as the two principal sources of N2O consistent with the inventory, but shows that N2O contributions attributed to the transportation sector are overestimated in the statewide inventory. These new top down constraints should be used to correct these errors in the current bottom-up inventory, which is a critical step for future assessments of the efficacy of emission reduction regulations. Particularly, measurement techniques like vehicle dynamometer emission calculations (for transportation sources), source-specific short range ground-based inverse dispersion (for dairy and livestock sources), airborne eddy covariance and airborne mass balance approach based emissions estimation (over oil and gas fields) and ground based eddy-covariance (for wetlands and agriculture sector) can be used effectively to generate direct emissions estimates for methane and nitrous oxide that help update and improve the accuracy of the state inventory.

Trace elements and common ions in southeastern Idaho snow: Regional air pollutant tracers for source area emissions

USGS Publications Warehouse

Abbott, M.; Einerson, J.; Schuster, P.; Susong, D.; Taylor, Howard E.; ,

2004-01-01

Snow sampling and analysis methods which produce accurate and ultra-low measurements of trace elements and common ion concentration in southeastern Idaho snow, were developed. Snow samples were collected over two winters to assess trace elements and common ion concentrations in air pollutant fallout across the southeastern Idaho. The area apportionment of apportionment of fallout concentrations measured at downwind location were investigated using pattern recognition and multivariate statistical technical techniques. Results show a high level of contribution from phosphates processing facilities located outside Pocatello in the southern portion of the Eastern Snake River Plain, and no obvious source area profiles other than at Pocatello.

Open Source Tools for Numerical Simulation of Urban Greenhouse Gas Emissions

NASA Astrophysics Data System (ADS)

Nottrott, A.; Tan, S. M.; He, Y.

2016-12-01

There is a global movement toward urbanization. Approximately 7% of the global population lives in just 28 megacities, occupying less than 0.1% of the total land area used by human activity worldwide. These cities contribute a significant fraction of the global budget of anthropogenic primary pollutants and greenhouse gasses. The 27 largest cities consume 9.9%, 9.3%, 6.7% and 3.0% of global gasoline, electricity, energy and water use, respectively. This impact motivates novel approaches to quantify and mitigate the growing contribution of megacity emissions to global climate change. Cities are characterized by complex topography, inhomogeneous turbulence, and variable pollutant source distributions. These features create a scale separation between local sources and urban scale emissions estimates known as the Grey-Zone. Modern computational fluid dynamics (CFD) techniques provide a quasi-deterministic, physically based toolset to bridge the scale separation gap between source level dynamics, local measurements, and urban scale emissions inventories. CFD has the capability to represent complex building topography and capture detailed 3D turbulence fields in the urban boundary layer. This presentation discusses the application of OpenFOAM to urban CFD simulations of natural gas leaks in cities. OpenFOAM is an open source software for advanced numerical simulation of engineering and environmental fluid flows. When combined with free or low cost computer aided drawing and GIS, OpenFOAM generates a detailed, 3D representation of urban wind fields. OpenFOAM was applied to model methane (CH4) emissions from various components of the natural gas distribution system, to investigate the impact of urban meteorology on mobile CH4 measurements. The numerical experiments demonstrate that CH4 concentration profiles are highly sensitive to the relative location of emission sources and buildings. Sources separated by distances of 5-10 meters showed significant differences in vertical dispersion of the plume due to building wake effects. The OpenFOAM flow fields were combined with an inverse, stochastic dispersion model to quantify and visualize the sensitivity of point sensors to upwind sources in various built environments.

Spatially- explicit Fossil Fuel Carbon Dioxide Inventories for Transportation in the U.S.

NASA Astrophysics Data System (ADS)

Hutchins, M.; Gurney, K. R.

2016-12-01

The transportation sector is the second largest source of Fossil Fuel CO2 (FFCO2) emissions, and is unique in that federal, state, and municipal levels of government are all able to enact transportation policy. However, since data related to transportation activities are reported by multiple different government agencies, the data are not always consistent. As a result, the methods and data used to inventory and account for transportation related FFCO2 emissions have important implications for both science and policy. Aggregate estimates of transportation related FFCO2 emissions can be spatially distributed using traffic data, such as the Highway Performance Monitoring System (HPMS) Average Annual Daily Traffic (AADT). There are currently two datasets that estimate the spatial distribution of transportation related FFCO2 in the United States- Vulcan 3.0 and the Database of Road Transportation Emissions (DARTE). Both datasets are at 1 km resolution, for the year 2011, and utilize HPMS AADT traffic data. However, Vulcan 3.0 and DARTE spatially distribute emissions using different methods and inputs, resulting in a number of differences. Vulcan 3.0 and DARTE estimate national transportation related FFCO2 emissions within 2.5% of each other, with more significant differences at the county and state level. The differences are most notable in urban versus rural regions, and for specific road classes. The origin of these differences are explored in depth to understand the implication of using specific data sources, such as the National Emissions Inventory and other aggregate transportation statistics from the Federal Highway Administration (FHWA). In addition to comparing Vulcan 3.0 and DARTE to each other, the results from both data sets are compared to independent traffic volume measurements acquired from the FHWA Continuous Count Station (CCS) network. The CCS records hourly traffic counts at fixed locations in space throughout the U.S. We calculate transportation related FFCO2 emissions at a CCS stations using fuel specific emissions factors combined with the raw traffic counts. The CCS network provides a unique opportunity to compare spatially explicit, "bottom-up" models of transportation related FFCO2 emissions to measured traffic volume at over 300 specific locations.

Characterizing Methane Emissions at Local Scales with a 20 Year Total Hydrocarbon Time Series, Imaging Spectrometry, and Web Facilitated Analysis

NASA Astrophysics Data System (ADS)

Bradley, Eliza Swan

Methane is an important greenhouse gas for which uncertainty in local emission strengths necessitates improved source characterizations. Although CH4 plume mapping did not motivate the NASA Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) design and municipal air quality monitoring stations were not intended for studying marine geological seepage, these assets have capabilities that can make them viable for studying concentrated (high flux, highly heterogeneous) CH4 sources, such as the Coal Oil Point (COP) seep field (˜0.015 Tg CH4 yr-1) offshore Santa Barbara, California. Hourly total hydrocarbon (THC) data, spanning 1990 to 2008 from an air pollution station located near COP, were analyzed and showed geologic CH4 emissions as the dominant local source. A band ratio approach was developed and applied to high glint AVIRIS data over COP, resulting in local-scale mapping of natural atmospheric CH4 plumes. A Cluster-Tuned Matched Filter (CTMF) technique was applied to Gulf of Mexico AVIRIS data to detect CH4 venting from offshore platforms. Review of 744 platform-centered CTMF subsets was facilitated through a flexible PHP-based web portal. This dissertation demonstrates the value of investigating municipal air quality data and imaging spectrometry for gathering insight into concentrated methane source emissions and highlights how flexible web-based solutions can help facilitate remote sensing research.

EXTERNALLY HEATED PROTOSTELLAR CORES IN THE OPHIUCHUS STAR-FORMING REGION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindberg, Johan E.; Charnley, Steven B.; Cordiner, Martin A.

We present APEX 218 GHz observations of molecular emission in a complete sample of embedded protostars in the Ophiuchus star-forming region. To study the physical properties of the cores, we calculate H{sub 2}CO and c -C{sub 3}H{sub 2} rotational temperatures, both of which are good tracers of the kinetic temperature of the molecular gas. We find that the H{sub 2}CO temperatures range between 16 K and 124 K, with the highest H{sub 2}CO temperatures toward the hot corino source IRAS 16293-2422 (69–124 K) and the sources in the ρ Oph A cloud (23–49 K) located close to the luminous Herbigmore » Be star S1, which externally irradiates the ρ Oph A cores. On the other hand, the c -C{sub 3}H{sub 2} rotational temperature is consistently low (7–17 K) in all sources. Our results indicate that the c -C{sub 3}H{sub 2} emission is primarily tracing more shielded parts of the envelope whereas the H{sub 2}CO emission (at the angular scale of the APEX beam; 3600 au in Ophiuchus) mainly traces the outer irradiated envelopes, apart from in IRAS 16293-2422, where the hot corino emission dominates. In some sources, a secondary velocity component is also seen, possibly tracing the molecular outflow.« less

SPod Progress Summary Slides | Science Inventory | US EPA

EPA Pesticide Factsheets

This presentation describes the draft “open source” design package for the SPod fenceline sensor. The SPod is a low cost, solar-powered system that combines wind field and air pollutant concentration measurements to detect emission plumes and help locate the source of emissions. The current design works only in “near-fenceline” applications where localized source emission plumes may be present. The SPod uses data analysis software (described elsewhere) to separate baseline drift from the plume signal of interest. This software is necessary for proper operation of the SPod. Because the SPod is designed to detect source emissions plumes, it is not useful for ambient applications large distances away from sources. The current SPod detects a subset of air pollutants that can be ionized with a 10.6 eV photoionization detector (PID). In the future, other air pollutant sensors may be used. The purpose of this presentation and related postings is to advance design concepts in the low-cost fenceline sensor area with any interested parties. The SPod is a work in progress with continued advances incorporated on an ongoing basis. This document is posted on an EPA share drive along with other information that describes the use operation and limitations of the SPod. These slides summarize the SPod design, purpose, and progress as of June, 2016. These slides will be posted on the EPA SPod Share Site along with design information and other materials that communicat

Deriving realistic source boundary conditions for a CFD simulation of concentrations in workroom air.

PubMed

Feigley, Charles E; Do, Thanh H; Khan, Jamil; Lee, Emily; Schnaufer, Nicholas D; Salzberg, Deborah C

2011-05-01

Computational fluid dynamics (CFD) is used increasingly to simulate the distribution of airborne contaminants in enclosed spaces for exposure assessment and control, but the importance of realistic boundary conditions is often not fully appreciated. In a workroom for manufacturing capacitors, full-shift samples for isoamyl acetate (IAA) were collected for 3 days at 16 locations, and velocities were measured at supply grills and at various points near the source. Then, velocity and concentration fields were simulated by 3-dimensional steady-state CFD using 295K tetrahedral cells, the k-ε turbulence model, standard wall function, and convergence criteria of 10(-6) for all scalars. Here, we demonstrate the need to represent boundary conditions accurately, especially emission characteristics at the contaminant source, and to obtain good agreement between observations and CFD results. Emission rates for each day were determined from six concentrations measured in the near field and one upwind using an IAA mass balance. The emission was initially represented as undiluted IAA vapor, but the concentrations estimated using CFD differed greatly from the measured concentrations. A second set of simulations was performed using the same IAA emission rates but a more realistic representation of the source. This yielded good agreement with measured values. Paying particular attention to the region with highest worker exposure potential-within 1.3 m of the source center-the air speed and IAA concentrations estimated by CFD were not significantly different from the measured values (P = 0.92 and P = 0.67, respectively). Thus, careful consideration of source boundary conditions greatly improved agreement with the measured values.

Survey of Large Methane Emitters in North America

NASA Astrophysics Data System (ADS)

Deiker, S.

2017-12-01

It has been theorized that methane emissions in the oil and gas industry follow log normal or "fat tail" distributions, with large numbers of small sources for every very large source. Such distributions would have significant policy and operational implications. Unfortunately, by their very nature such distributions would require large sample sizes to verify. Until recently, such large-scale studies would be prohibitively expensive. The largest public study to date sampled 450 wells, an order of magnitude too low to effectively constrain these models. During 2016 and 2017, Kairos Aerospace conducted a series of surveys the LeakSurveyor imaging spectrometer, mounted on light aircraft. This small, lightweight instrument was designed to rapidly locate large emission sources. The resulting survey covers over three million acres of oil and gas production. This includes over 100,000 wells, thousands of storage tanks and over 7,500 miles of gathering lines. This data set allows us to now probe the distribution of large methane emitters. Results of this survey, and implications for methane emission distribution, methane policy and LDAR will be discussed.

The Fermi Large Area Telescope Thrid Gamma-ray Source Catalog

NASA Astrophysics Data System (ADS)

Stephens, Thomas E.; Ballet, Jean; Burnett, Toby; Cavazzuti, Elisabetta; Digel, Seth William; Fermi LAT Collaboration

2015-01-01

We present an overview of the third Fermi Large Area Telescope source catalog (3FGL) of sources in the 100 MeV - 300 GeV range. Based on the first four years of science data from the Fermi Gamma-ray Space Telescope mission, it is the deepest yet in this energy range. Relative to the 2FGL catalog (Nolan et al. 2012, ApJS 199, 31), the 3FGL catalog incorporates twice as much data as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse gamma-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. The 3FGL catalog includes 3033 sources, with source location regions, spectral properties, and monthly light curves for each. For approximately one-third of the sources we have not found counterparts at other wavelengths. More than 1100 of the identified or associated sources are active galaxies of the blazar class; several other classes of non-blazar active galaxies are also represented in the 3FGL. Pulsars represent the largest Galactic source class. From source counts of Galactic sources we estimate the contribution of unresolved sources to the Galactic diffuse emission.

UNCOVERING THE NUCLEUS CANDIDATE FOR NGC 253

DOE Office of Scientific and Technical Information (OSTI.GOV)

Günthardt, G. I.; Camperi, J. A.; Agüero, M. P.

2015-11-15

NGC 253 is the nearest spiral galaxy with a nuclear starburst that becomes the best candidate for studying the relationship between starburst and active galactic nucleus activity. However, this central region is veiled by large amounts of dust, and it has been so far unclear which is the true dynamical nucleus to the point that there is no strong evidence that the galaxy harbors a supermassive black hole co-evolving with the starburst as was supposed earlier. Near-infrared (NIR) spectroscopy, especially NIR emission line analysis, could be advantageous in shedding light on the true nucleus identity. Using Flamingos-2 at Gemini Southmore » we have taken deep K-band spectra along the major axis of the central structure and through the brightest infrared source. In this work, we present evidence showing that the brightest NIR and mid-infrared source in the central region, already known as radio source TH7 and so far considered just a large stellar supercluster, in fact presents various symptoms of a genuine galactic nucleus. Therefore, it should be considered a valid nucleus candidate. Mentioning some distinctive aspects, it is the most massive compact infrared object in the central region, located at 2.″0 of the symmetry center of the galactic bar, as measured in the K-band emission. Moreover, our data indicate that this object is surrounded by a large circumnuclear stellar disk and it is also located at the rotation center of the large molecular gas disk of NGC 253. Furthermore, a kinematic residual appears in the H{sub 2} rotation curve with a sinusoidal shape consistent with an outflow centered in the candidate nucleus position. The maximum outflow velocity is located about 14 pc from TH7, which is consistent with the radius of a shell detected around the nucleus candidate, observed at 18.3 μm (Qa) and 12.8 μm ([Ne ii]) with T-ReCS. Also, the Brγ emission line profile shows a pronounced blueshift and this emission line also has the highest equivalent width at this position. All this evidence points to TH7 as the best candidate for the galactic nucleus of NGC 253.« less

Algae Biofuels Co-Location Assessment Tool for Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

2011-11-29

The Algae Biofuels Co-Location Assessment Tool for Canada uses chemical stoichiometry to estimate Nitrogen, Phosphorous, and Carbon atom availability from waste water and carbon dioxide emissions streams, and requirements for those same elements to produce a unit of algae. This information is then combined to find limiting nutrient information and estimate potential productivity associated with waste water and carbon dioxide sources. Output is visualized in terms of distributions or spatial locations. Distances are calculated between points of interest in the model using the great circle distance equation, and the smallest distances found by an exhaustive search and sort algorithm.

Plasma and radio waves from Neptune: Source mechanisms and propagation

NASA Astrophysics Data System (ADS)

Wong, H. K.

1994-03-01

This report summarizes results obtained through the support of NASA Grant NAGW-2412. The objective of this project is to conduct a comprehensive investigation of the radio wave emission observed by the planetary radio astronomy (PRA) instrument on board Voyager 2 as if flew by Neptune. This study has included data analysis, theoretical and numerical calculations, ray tracing, and modeling to determine the possible source mechanism(s) and locations of the Neptune radio emissions. We have completed four papers, which are included in the appendix. The paper 'Modeling of Whistler Ray Paths in the Magnetosphere of Neptune' investigated the propagation and dispersion of lighting-generated whistler in the magnetosphere of Neptune by using three dimensional ray tracing. The two papers 'Numerical Simulations of Bursty Radio Emissions from Planetary Magnetospheres' and 'Numerical Simulations of Bursty Planetary Radio Emissions' employed numerical simulations to investigate an alternate source mechanism of bursty radio emissions in addition to the cyclotron maser instability. We have also studied the possible generation of Z and whistler mode waves by the temperature anisotropic beam instability and the result was published in 'Electron Cyclotron Wave Generation by Relativistic Electrons.' Besides the aforementioned studies, we have also collaborated with members of the PRA team to investigate various aspects of the radio wave data. Two papers have been submitted for publication and the abstracts of these papers are also listed in the appendix.

Plasma and radio waves from Neptune: Source mechanisms and propagation

NASA Technical Reports Server (NTRS)

Wong, H. K.

1994-01-01

This report summarizes results obtained through the support of NASA Grant NAGW-2412. The objective of this project is to conduct a comprehensive investigation of the radio wave emission observed by the planetary radio astronomy (PRA) instrument on board Voyager 2 as if flew by Neptune. This study has included data analysis, theoretical and numerical calculations, ray tracing, and modeling to determine the possible source mechanism(s) and locations of the Neptune radio emissions. We have completed four papers, which are included in the appendix. The paper 'Modeling of Whistler Ray Paths in the Magnetosphere of Neptune' investigated the propagation and dispersion of lighting-generated whistler in the magnetosphere of Neptune by using three dimensional ray tracing. The two papers 'Numerical Simulations of Bursty Radio Emissions from Planetary Magnetospheres' and 'Numerical Simulations of Bursty Planetary Radio Emissions' employed numerical simulations to investigate an alternate source mechanism of bursty radio emissions in addition to the cyclotron maser instability. We have also studied the possible generation of Z and whistler mode waves by the temperature anisotropic beam instability and the result was published in 'Electron Cyclotron Wave Generation by Relativistic Electrons.' Besides the aforementioned studies, we have also collaborated with members of the PRA team to investigate various aspects of the radio wave data. Two papers have been submitted for publication and the abstracts of these papers are also listed in the appendix.

Understanding workers' exposure: Systematic review and data-analysis of emission potential for NOAA.

PubMed

Kuijpers, E; Bekker, C; Brouwer, D; le Feber, M; Fransman, W

2017-05-01

Exposure assessment for nano-objects, and their aggregates and agglomerates (NOAA), has evolved from explorative research toward more comprehensive exposure assessment, providing data to further develop currently used conservative control banding (CB) tools for risk assessment. This study aims to provide an overview of current knowledge on emission potential of NOAA across the occupational life cycle stages by a systematic review and subsequently use the results in a data analysis. Relevant parameters that influence emission were collected from peer-reviewed literature with a focus on the four source domains (SD) in the source-receptor conceptual framework for NOAA. To make the reviewed exposure data comparable, we applied an approach to normalize for workplace circumstances and measurement location, resulting in comparable "surrogate" emission levels. Finally, descriptive statistics were performed. During the synthesis of nanoparticles (SD1), mechanical reduction and gas phase synthesis resulted in the highest emission compared to wet chemistry and chemical vapor condensation. For the handling and transfer of bulk manufactured nanomaterial powders (SD2) the emission could be differentiated for five activity classes: (1) harvesting; (2) dumping; (3); mixing; (4) cleaning of a reactor; and (5) transferring. Additionally, SD2 was subdivided by the handled amount with cleaning further subdivided by energy level. Harvesting and dumping resulted in the highest emissions. Regarding processes with liquids (SD3b), it was possible to distinguish emissions for spraying (propellant gas, (high) pressure and pump), sonication and brushing/rolling. The highest emissions observed in SD3b were for propellant gas spraying and pressure spraying. The highest emissions for the handling of nano-articles (SD4) were found to nano-sized particles (including NOAA) for grinding. This study provides a valuable overview of emission assessments performed in the workplace during the occupational handling of NOAA. Analyses were made per source domain to derive emission levels which can be used for models to quantitatively predict the exposure.

Variations in the methane budget over the last two millennia

NASA Astrophysics Data System (ADS)

Derendorp, L.

2012-06-01

Leaf litter is available at the Earth’s surface in large quantities. During the decomposition of leaf litter, volatile compounds can be released into the atmosphere, where they potentially influence local air quality, atmospheric chemistry or the global climate. In this thesis the focus was on the emission of C2-C5 hydrocarbons, molecular hydrogen (H2), carbon monoxide (CO) and methyl chloride (CH3Cl) from leaf litter and the factors that control the emissions were investigated. For different plant species, the emission rates of several C2-C5 hydrocarbons increased with temperature between 20 and 100°C according to the Arrhenius relation. When leaf litter was irradiated with UV, the emission increased linearly with the intensity of the UV. UVB radiation was more efficient in the generation of hydrocarbons from leaf litter than UVA. A simple upscaling showed that C2-C5 hydrocarbon emissions from leaf litter are likely insignificant for their global budgets, but may have a small influence on atmospheric chemistry on the local scale. Senescent and dead plant material releases carbon monoxide (CO), methane and larger hydrocarbons upon heating or irradiation with UV, but emissions of hydrogen (H2) have not been reported. In this study, H2 was released from leaf litter of Sequoiadendron giganteum in detectable amounts at temperatures above 45°C, whereas CO was also emitted at ambient temperature. Leaf litter has been identified as a potentially important source of CH3Cl. However, the factors controlling the emissions are unclear. Laboratory experiments have been performed in which CH3Cl emissions were measured from leaf litter of different plant species. For each investigated plant species, the CH3Cl emission rate strongly increased with temperature according to the Arrhenius relation. However, at constant temperature, large differences between different plants were observed. Therefore, CH3Cl emissions were measured from halophyte leaf litter with a varying chloride content, but no significant correlation between the CH3Cl emission rate and the chloride content of the plant material was observed. A limited set of field experiments was performed in which CH3Cl emissions were measured. Leaf litter emitted CH3Cl, but only in periods with fresh leaf litter fall. Outside these periods, the flux from leaf litter was zero or even slightly negative. The CH3Cl emission rate increased with temperature, but the temperature increase did not follow the Arrhenius relation as was observed in the laboratory experiments. The global importance of leaf litter as a source of CH3Cl was investigated using the global chemistry transport model TM5. Forward simulations with different emission scenarios indicated that at station Trinidad Head (mid-latitudes of North America), a substantial seasonal emission from leaf litter was required to match the measured CH3Cl mixing ratios at this station. Inversions performed with the TM4-4D-Var system indicated that the main CH3Cl sources were located in the Tropics, whereas the mid- and high latitudes were only a minor source. Sensitivity studies performed to investigate the robustness of the optimized emissions indicated that more than 90% of the global net emissions was located in the Tropics.

Acoustic emission measurements of aerospace materials and structures

NASA Technical Reports Server (NTRS)

Sachse, Wolfgang; Gorman, Michael R.

1993-01-01

A development status evaluation is given for aerospace applications of AE location, detection, and source characterization. Attention is given to the neural-like processing of AE signals for graphite/epoxy. It is recommended that development efforts for AE make connections between the material failure process and source dynamics, and study the effects of composite material anisotropy and inhomogeneity on the propagation of AE waves. Broadband, as well as frequency- and wave-mode selective sensors, need to be developed.

NO x emissions from large point sources: variability in ozone production, resulting health damages and economic costs

NASA Astrophysics Data System (ADS)

Mauzerall, Denise L.; Sultan, Babar; Kim, Namsoug; Bradford, David F.

We present a proof-of-concept analysis of the measurement of the health damage of ozone (O 3) produced from nitrogen oxides (NO=NO+NO) emitted by individual large point sources in the eastern United States. We use a regional atmospheric model of the eastern United States, the Comprehensive Air quality Model with Extensions (CAMx), to quantify the variable impact that a fixed quantity of NO x emitted from individual sources can have on the downwind concentration of surface O 3, depending on temperature and local biogenic hydrocarbon emissions. We also examine the dependence of resulting O 3-related health damages on the size of the exposed population. The investigation is relevant to the increasingly widely used "cap and trade" approach to NO x regulation, which presumes that shifts of emissions over time and space, holding the total fixed over the course of the summer O 3 season, will have minimal effect on the environmental outcome. By contrast, we show that a shift of a unit of NO x emissions from one place or time to another could result in large changes in resulting health effects due to O 3 formation and exposure. We indicate how the type of modeling carried out here might be used to attach externality-correcting prices to emissions. Charging emitters fees that are commensurate with the damage caused by their NO x emissions would create an incentive for emitters to reduce emissions at times and in locations where they cause the largest damage.

Photochemical Grid Modelling Study to Assess Potential Air Quality Impacts Associated with Energy Development in Colorado and Northern New Mexico.

NASA Astrophysics Data System (ADS)

Parker, L. K.; Morris, R. E.; Zapert, J.; Cook, F.; Koo, B.; Rasmussen, D.; Jung, J.; Grant, J.; Johnson, J.; Shah, T.; Pavlovic, T.

2015-12-01

The Colorado Air Resource Management Modeling Study (CARMMS) was funded by the Bureau of Land Management (BLM) to predict the impacts from future federal and non-federal energy development in Colorado and Northern New Mexico. The study used the Comprehensive Air Quality Model with extensions (CAMx) photochemical grid model (PGM) to quantify potential impacts from energy development from BLM field office planning areas. CAMx source apportionment technology was used to track the impacts from multiple (14) different emissions source regions (i.e. field office areas) within one simulation, as well as to assess the cumulative impact of emissions from all source regions combined. The energy development emissions estimates were for the year 2021 for three different development scenarios: (1) low; (2) high; (3) high with emissions mitigation. Impacts on air quality (AQ) including ozone, PM2.5, PM10, NO2, SO2, and air quality related values (AQRVs) such as atmospheric deposition, regional haze and changes in Acid Neutralizing Capacity (ANC) of lakes were quantified, and compared to establish threshold levels. In this presentation, we present a brief summary of the how the emission scenarios were developed, we compare the emission totals for each scenario, and then focus on the ozone impacts for each scenario to assess: (1). the difference in potential ozone impacts under the different development scenarios and (2). to establish the sensitivity of the ozone impacts to different emissions levels. Region-wide ozone impacts will be presented as well as impacts at specific locations with ozone monitors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Gasperin, F.; Ogrean, G. A.; van Weeren, R. J.

We report that extended steep-spectrum radio emission in a galaxy cluster is usually associated with a recent merger. However, given the complex scenario of galaxy cluster mergers, many of the discovered sources hardly fit into the strict boundaries of a precise taxonomy. This is especially true for radio phoenixes that do not have very well defined observational criteria. Radio phoenixes are aged radio galaxy lobes whose emission is reactivated by compression or other mechanisms. Here in this paper, we present the detection of a radio phoenix close to the moment of its formation. The source is located in Abell 1033,more » a peculiar galaxy cluster which underwent a recent merger. To support our claim, we present unpublished Westerbork Synthesis Radio Telescope and Chandra observations together with archival data from the Very Large Array and the Sloan Digital Sky Survey. We discover the presence of two subclusters displaced along the N–S direction. The two subclusters probably underwent a recent merger which is the cause of a moderately perturbed X-ray brightness distribution. A steep-spectrum extended radio source very close to an active galactic nucleus (AGN) is proposed to be a newly born radio phoenix: the AGN lobes have been displaced/compressed by shocks formed during the merger event. This scenario explains the source location, morphology, spectral index, and brightness. Finally, we show evidence of a density discontinuity close to the radio phoenix and discuss the consequences of its presence.« less

Occurrence statistics and ray tracing study of Jovian quasiperiodic radio bursts observed from low latitudes

NASA Astrophysics Data System (ADS)

Kimura, Tomoki; Tsuchiya, Fuminori; Misawa, Hiroaki; Morioka, Akira; Nozawa, Hiromasa

2010-05-01

The occurrence characteristics of Jovian quasiperiodic (QP) bursts at a VLF range (<10 kHz) were statistically investigated using data from the Galileo spacecraft at low latitudes in the Jovian magnetosphere. The results confirmed that the occurrence of QP bursts is significantly dependent on the phase of planetary rotation rather than the central meridian longitude of the observer seen from Jupiter. It was revealed that the meridional distribution of QP bursts forms a shadow zone in the equatorial region of <30 Jovian radii from Jupiter, similar to that of hectometric radio emissions, where QP bursts are quenched. Based on the ray tracing method, we surveyed the source parameters, which can reproduce the observed shadow zone. It was suggested that the wave mode, source location, and directivity of the radio emissions are as follows: the extraordinary mode is reasonable for QP bursts observed at low latitudes, the source is located around an altitude of ˜10-20 Jovian radii above the polar region, the L value of the source field line is in a range of L > ˜20, and QP bursts could have beaming angles like “filled cone” in a restricted L value range or have a large source L value range with beaming angles like “hollow cones.” These results imply that QP bursts observed at low latitudes are generated at fRX surfaces in the polar region and propagate to the equatorial region.

A global high-resolution emission inventory for ammonia

NASA Astrophysics Data System (ADS)

Bouwman, A. F.; Lee, D. S.; Asman, W. A. H.; Dentener, F. J.; van der Hoek, K. W.; Olivier, J. G. J.

1997-12-01

A global emissions inventory for ammonia (NH3) has been compiled for the main known sources on a 1° × 1° grid, suitable for input to global atmospheric models. The estimated global emission for 1990 is about 54 Tg N yr-1. The major sources identified include excreta from domestic animals (21.6 Tg N yr-1) and wild animals (0.1 Tg N yr-1), use of synthetic N fertilizers (9.0 Tg N yr-1), oceans (8.2 Tg N yr-1), biomass burning (5.9 Tg N yr-1), crops (3.6 Tg N yr-1), human population and pets (2.6 Tg N yr-1), soils under natural vegetation (2.4 Tg N yr-1), industrial processes (0.2 Tg N yr-1 ), and fossil fuels (0.1 Tg N yr-1). About half of the global emission comes from Asia, and about 70% is related to food production. The regions with highest emission rates are located in Europe, the Indian subcontinent, and China, reflecting the patterns of animal densities and type and intensity of synthetic fertilizer use. The overall uncertainty in the global emission estimate is 25%, while the uncertainty in regional emissions is much greater. As the global human population will show considerable growth in the coming decades, food production and associated NH3 emissions are likely to increase as well.

Climate Change Impacts of US Reactive Nitrogen Emissions

NASA Astrophysics Data System (ADS)

Pinder, R. W.; Davidson, E. A.; Goodale, C. L.; Greaver, T.; Herrick, J.; Liu, L.

2011-12-01

By fossil fuel combustion and fertilizer application, the US has substantially altered the nitrogen cycle, with serious effects on climate change. The climate effects can be short-lived, by impacting the chemistry of the atmosphere, or long-lived, by altering ecosystem greenhouse gas fluxes. Here, we develop a coherent framework for assessing the climate change impacts of US reactive nitrogen emissions. We use the global temperature potential (GTP) as a common metric, and we calculate the GTP at 20 and 100 years in units of CO2 equivalents. At both time-scales, nitrogen enhancement of CO2 uptake has the largest impact, because in the eastern US, areas of high nitrogen deposition are co-located with forests. In the short-term, the effect due to NOx altering ozone and methane concentrations is also substantial, but are not important on the 100 year time scale. Finally, the GTP of N2O emissions is substantial at both time scales. We have also attributed these impacts to combustion and agricultural sources, and quantified the uncertainty. Reactive nitrogen from combustion sources contribute more to cooling than warming. The impacts of agricultural sources tend to cancel each other out, and the net effect is uncertain. Recent trends show decreasing reactive nitrogen from US combustion sources, while agricultural sources are increasing. Fortunately, there are many mitigation strategies currently available to reduce the climate change impacts of US agricultural sources.

Chemical compositions and source identification of PM₂.₅ aerosols for estimation of a diesel source surrogate.

PubMed

Sahu, Manoranjan; Hu, Shaohua; Ryan, Patrick H; Le Masters, Grace; Grinshpun, Sergey A; Chow, Judith C; Biswas, Pratim

2011-06-01

Exposure to traffic-related pollution during childhood has been associated with asthma exacerbation, and asthma incidence. The objective of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) is to determine if the development of allergic and respiratory disease is associated with exposure to diesel engine exhaust particles. A detailed receptor model analyses was undertaken by applying positive matrix factorization (PMF) and UNMIX receptor models to two PM₂.₅ data sets: one consisting of two carbon fractions and the other of eight temperature-resolved carbon fractions. Based on the source profiles resolved from the analyses, markers of traffic-related air pollution were estimated: the elemental carbon attributed to traffic (ECAT) and elemental carbon attributed to diesel vehicle emission (ECAD). Application of UNMIX to the two data sets generated four source factors: combustion related sulfate, traffic, metal processing and soil/crustal. The PMF application generated six source factors derived from analyzing two carbon fractions and seven factors from temperature-resolved eight carbon fractions. The source factors (with source contribution estimates by mass concentrations in parentheses) are: combustion sulfate (46.8%), vegetative burning (15.8%), secondary sulfate (12.9%), diesel vehicle emission (10.9%), metal processing (7.5%), gasoline vehicle emission (5.6%) and soil/crustal (0.7%). Diesel and gasoline vehicle emission sources were separated using eight temperature-resolved organic and elemental carbon fractions. Application of PMF to both datasets also differentiated the sulfate rich source from the vegetative burning source, which are combined in a single factor by UNMIX modeling. Calculated ECAT and ECAD values at different locations indicated that traffic source impacts depend on factors such as traffic volumes, meteorological parameters, and the mode of vehicle operation apart from the proximity of the sites to highways. The difference in ECAT and ECAD, however, was less than one standard deviation. Thus, a cost benefit consideration should be used when deciding on the benefits of an eight or two carbon approach. Published by Elsevier B.V.

Natural or anthropogenic? On the origin of atmospheric sulfate deposition in the Andes of southeastern Ecuador

NASA Astrophysics Data System (ADS)

Makowski Giannoni, S.; Rollenbeck, R.; Trachte, K.; Bendix, J.

2014-05-01

Atmospheric sulfur deposition above certain limits can represent a threat to tropical forests, causing nutrient imbalances and mobilizing toxic elements that impact biodiversity and forest productivity. Atmospheric sources of sulfur deposited by precipitation have being roughly identified in only a few lowland tropical forests. Even scarcer are these type of studies in tropical mountain forests, many of them megadiversity hotspots and especially vulnerable to acidic deposition. Here, the topographic complexity and related streamflow condition the origin, type, and intensity of deposition. Furthermore, in regions with a variety of natural and anthropogenic sulfur sources, like active volcanoes and biomass-burning, no source-emission data has been used for determining the contribution of each of them to the deposition. The main goal of the current study is to evaluate sulfate (SO4-) deposition by rain and occult precipitation at two topographic locations in a tropical mountain forest of southern Ecuador, and to trace back the deposition to possible emission sources applying back trajectory modeling. To link upwind natural (volcanic) and anthropogenic (urban/industrial and biomass-burning) sulfur emissions and observed sulfate deposition, we employed state of the art inventory and satellite data, including volcanic passive degassing as well. We conclude that biomass-burning sources generally dominate sulfate deposition at the evaluated sites. Minor sulfate transport occurs during the shifting of the predominant winds to the north and west. Occult precipitation sulfate deposition and likely rain sulfate deposition are mainly linked to biomass-burning emissions from the Amazon lowlands. Volcanic and anthropogenic emissions from the north and west contribute to occult precipitation sulfate deposition at the mountain crest Cerro del Consuelo meteorological station and to rain-deposited sulfate at the upriver mountain-pass El Tiro meteorological station.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutiérrez, Carlos M.; Moon, Dae-Sik, E-mail: cgc@iac.es

We present the identification and characterization of the optical counterpart to 2XMM J011942.7+032421, one of the most luminous and distant ultra-luminous X-ray sources (ULXs). The counterpart is located near a star-forming region in a spiral arm of the galaxy NGC 470 with u, g, and r magnitudes of 21.53, 21.69, and 21.71 mag, respectively. The luminosity of the counterpart is much larger than that of a single O-type star, indicating that it may be a stellar cluster. Our optical spectroscopic observations confirm the association of the X-ray source and the optical counterpart with its host galaxy NGC 470, which validates the high,more » ≳10{sup 41} erg s{sup -1}, X-ray luminosity of the source. Its optical spectrum is embedded with numerous emission lines, including H recombination lines, metallic forbidden lines, and more notably the high-ionization He II (λ4686) line. That line shows a large velocity dispersion of ≅410 km s{sup -1}, consistent with the existence of a compact (<5 AU) highly ionized accretion disk rotating around the central X-ray source. The ∼1.4 × 10{sup 37} erg s{sup -1} luminosity of the He II line emission makes the source one of the most luminous ULXs in that emission. This, together with the high X-ray luminosity and the large velocity dispersion of the He II emission, suggests that the source is an ideal candidate for more extensive follow-up observations for understanding the nature of hyper-luminous X-ray sources, a more luminous subgroup of ULXs, and more likely candidates for intermediate-mass black holes.« less

Impacts of Climate Change on Surface Ozone and Intercontinental Ozone Pollution: A Multi-Model Study

NASA Technical Reports Server (NTRS)

Doherty, R. M.; Wild, O.; Shindell, D. T.; Zeng, G.; MacKenzie, I. A.; Collins, W. J.; Fiore, A. M.; Stevenson, D. S.; Dentener, F. J.; Schultz, M. G.;

Spatiotemporal comparison of highly-resolved emissions and concentrations of carbon dioxide and criteria pollutants in Salt Lake City, Utah for health and policy applications

NASA Astrophysics Data System (ADS)

Mendoza, D. L.; Lin, J. C.; Mitchell, L.; Gurney, K. R.; Patarasuk, R.; Fasoli, B.; Bares, R.; o'Keefe, D.; Song, T.; Huang, J.; Horel, J.; Crosman, E.; Ehleringer, J. R.

2015-12-01

This study addresses the need for robust highly-resolved emissions and concentration data required for planning purposes and policy development aimed at managing pollutant sources. Adverse health effects resulting from urban pollution exposure are dependent on proximity to emission sources and atmospheric mixing, necessitating models with high spatial and temporal resolution. As urban emission sources co-emit carbon dioxide (CO2) and criteria pollutants (CAPs), efforts to reduce specific pollutants would synergistically reduce others. We present emissions inventories and modeled concentrations for CO2 and CAPs: carbon monoxide (CO), lead (Pb), nitrogen oxides (NOx), particulate matter (PM2.5 and PM10), and sulfur oxides (SOx) for Salt Lake County, Utah. We compare the resulting concentrations against stationary and mobile measurement data and present a systematic quantification of uncertainties. The emissions inventory for CO2 is based on the Hestia emissions data inventory that resolves emissions at an hourly, building and road link resolution as well as hourly gridded emissions with a 0.002o x 0.002o spatial resolution. Two methods for deriving criteria pollutant emission inventories were compared. One was constructed using methods similar to Hestia but downscales total emissions based on the 2011 National Emissions Inventory (NEI). The other used Emission Modeling Clearinghouse spatial and temporal surrogates to downscale the NEI data from annual and county-level resolution to hourly and 0.002o x 0.002o grid cells. The gridded emissions from both criteria pollutant methods were compared against the Hestia CO2 gridded data to characterize spatial similarities and differences between them. Correlations were calculated at multiple scales of aggregation. The CALPUFF dispersion model was used to transport emissions and estimate air pollutant concentrations at an hourly 0.002o x 0.002o resolution. The resulting concentrations were spatially compared in the same manner as the emissions. Modeled results were compared against stationary measurements and from equipment mounted atop a light rail car in the Salt Lake City area. The comparison between both approaches to emissions estimation and resulting concentrations highlights spatial locations and hours of high variability and uncertainty.

Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

NASA Astrophysics Data System (ADS)

Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

2015-12-01

Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

Carbon isotope-constrained seasonality of carbonaceous aerosol sources from an urban location (Kanpur) in the Indo-Gangetic Plain

NASA Astrophysics Data System (ADS)

Bikkina, Srinivas; Andersson, August; Ram, Kirpa; Sarin, M. M.; Sheesley, Rebecca J.; Kirillova, Elena N.; Rengarajan, R.; Sudheer, A. K.; Gustafsson, Örjan

2017-05-01

The Indo-Gangetic Plain (IGP) in northern India, Pakistan, and Bangladesh is a major source of carbonaceous aerosols in South Asia. However, poorly constrained seasonality of their sources over the IGP leads to large uncertainty in climate and health effects. Here we present a first data set for year-round radiocarbon (Δ14C) and stable carbon (δ13C)-based source apportionment of total carbon (TC) in ambient PM10 (n = 17) collected from an urban site (Kanpur: 26.5°N, 80.3°E) in the IGP during January 2007 to January 2008. The year-round 14C-based fraction biomass (fbio-TC) estimate at Kanpur averages 77 ± 7% and emphasizes an impact of biomass burning emissions (BBEs). The highest fbio-TC (%) is observed in fall season (October-November, 85 ± 6%) followed by winter (December-February, 80 ± 4%) and spring (March-May, 75 ± 8%), while lowest values are found in summer (June-September, 69 ± 2%). Since biomass/coal combustion and vehicular emissions mostly contribute to carbonaceous aerosols over the IGP, we predict δ13CTC (δ13Cpred) over Kanpur using known δ13C source signatures and the measured Δ14C value of each sample. The seasonal variability of δ13Cobs - δ13Cpred versus Δ14CTC together with air mass back trajectories and Moderate Resolution Imaging Spectroradiometer fire count data reveal that carbonaceous aerosols in winter/fall are significantly influenced by atmospheric aging (downwind transport of crop residue burning/wood combustion emissions in the northern IGP), while local sources (wheat residue combustion/vehicular emissions) dominate in spring/summer. Given the large temporal and seasonal variability in sources and emission strength of TC over the IGP, 14C-based constraints are, thus, crucial for reducing their uncertainties in carbonaceous aerosol budgets in climate models.

40 CFR 63.7081 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) National Emission Standards for Hazardous Air Pollutants for Lime Manufacturing Plants What This Subpart... a lime manufacturing plant (LMP) that is a major source, or that is located at, or is part of, a... manufacture of lime product (calcium oxide, calcium oxide with magnesium oxide, or dead burned dolomite) by...

40 CFR 63.1407 - Non-reactor batch process vent provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Non-reactor batch process vent... § 63.1407 Non-reactor batch process vent provisions. (a) Emission standards. (1) Owners or operators of non-reactor batch process vents located at new or existing affected sources with 0.25 tons per year (0...

40 CFR 63.1407 - Non-reactor batch process vent provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Non-reactor batch process vent... § 63.1407 Non-reactor batch process vent provisions. (a) Emission standards. (1) Owners or operators of non-reactor batch process vents located at new or existing affected sources with 0.25 tons per year (0...

40 CFR 63.1346 - Standards for new or reconstructed raw material dryers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Standards for new or reconstructed raw... Industry Emission Standards and Operating Limits § 63.1346 Standards for new or reconstructed raw material dryers. (a) New or reconstructed raw material dryers located at facilities that are major sources can not...

40 CFR 63.2131 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast What This Subpart Covers § 63... nutritional yeast manufacturing facility that is, is located at, or is part of a major source of hazardous air pollutants (HAP) emissions. (1) A manufacturer of nutritional yeast is a facility that makes yeast for the...

40 CFR 63.2131 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast What This Subpart Covers § 63... nutritional yeast manufacturing facility that is, is located at, or is part of a major source of hazardous air pollutants (HAP) emissions. (1) A manufacturer of nutritional yeast is a facility that makes yeast for the...

76 FR 12863 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-09

..., sources asked for guidance regarding the requirement to conduct a temperature measurement calibration....6625(k)(4) to conduct a temperature measurement calibration check at least every 3 months, and asked... temperature gauge inserted in a thermal well co-located with the CPMS sensor. In both of the examples given...

Image digitising and analysis of outflows from young stars

NASA Astrophysics Data System (ADS)

Zealey, W. J.; Mader, S. L.

1997-08-01

We present IIIaJ, IIIaF and IVN band images of Herbig-Haro objects digitised from the ESO/SERC Southern Sky Survey plates. These form part of a digital image database of southern HH objects, which allows the identification of emission and reflection nebulosity and the location of the obscured sources of outflows.

Locating and Estimating Air Emissions From Sources Of 1,3 ...

EPA Pesticide Factsheets

... 1 H tu O • WI JSj ^ ^ "•^s ^ f > + \\ \\ 1 • 5 • 1 t ! 1 M 4 f * *• 4 1 £ « ; ' f, * " i ^ IC t L IA | • h : - ; : 2 i ! ~ • 5* i w - • M <» » 0 ... 3. Hawley, GG 1,3-Butadiene ...