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1

EMISSIONS OF NOX, SOX, AND VOC FROM ANTHROPOGENIC SOURCES  

EPA Science Inventory

The paper addresses the compilation of a 1980 emissions inventory for use in the National Acid Precipitation Assessment Program (NAPAP). The current inventory (Version 4.0) contains point source data for 50,200 plants with more than 201,000 emission points and area source data fo...

2

AREA SOURCES OF VOC EMISSIONS AND THEIR CONTRIBUTION TO TROPOSPHERIC OZONE CONCENTRATIONS  

EPA Science Inventory

The paper quantifies the importance of area sources to total volatile organic compound (VOC) emissions, reviews components of EPA/AEERL's non-attainment program, discusses the status of emission control or prevention for several area sources, and reviews some of the regulatory st...

3

[Inventory and environmental impact of VOCs emission from the typical anthropogenic sources in Sichuan province].  

PubMed

Based on Sichuan province environmental statistical survey data and other relevant activity data, volatile organic compounds (VOCs) emissions from typical anthropogenic sources in Sichuan province were calculated for the year of 2011 by applying the emission factor method. Besides, ozone and secondary organic aerosol formation potentials of these typical anthropogenic sources were discussed. The total VOC emission from these sources was about 482 kt in Sichuan province, biomass burning, solvent utilization, industrial processes, storage and distribution of fuel, and fossil fuel combustion contributed 174 kt, 153 kt, 121 kt, 21 kt and 13 kt, respectively; architecture wall painting, furniture coating, wood decoration painting and artificial board were the major emission sectors of the solvent utilization; while for the industrial processes, 19.4% of VOCs emission was from the wine industry. Chengdu was the largest contributor compared to the other cities in Sichuan, whose VOCs emission from these typical anthropogenic sources in 2011 was 112 kt. OFP of these sources was 1,930 kt altogether. Solvent utilization contributed 50.5% of the total SOA formation potentials, biomass burning and industrial processes both contributed about 23% , with storage and distribution of fuel and fossil fuel combustion accounting for 1% and 1.4%, respectively. PMID:24640887

Han, Li; Wang, Xing-Rui; He, Min; Guo, Wei-Guang

2013-12-01

4

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

NASA Astrophysics Data System (ADS)

Quantifying the contributions of methane (CH4) emissions from anthropogenic sources in the Central Valley of California is important for validation of the statewide greenhouse gas (GHG) inventory and subsequent AB32 law implementation. The state GHG inventory is largely based on activity data and emission factor based estimates. The 'bottom-up' emission factors for CH4 have large uncertainties and there is a lack of adequate 'top-down' measurements to characterize emission rates. Emissions from non-CO2 GHG sources display spatial heterogeneity and temporal variability, and are thus, often, poorly characterized. The Central Valley of California is an agricultural and industry intensive region with large concentration of dairies and livestock operations, active oil and gas fields and refining operations, as well as rice cultivation all of which are known CH4 sources. In order to gain a better perspective of the spatial distribution of major CH4 sources in California, airborne measurements were conducted aboard a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of low-altitude and mixed layer airborne CH4 and CO2 measurements alongside coincident VOC measurements. Transects during eight unique flights covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. We report direct quantification of CH4 fluxes using real-time airborne Eddy Covariance measurements. CH4 and CO2 were measured at 1-Hz data rate using an instrument based on Cavity Ring Down Spectroscopy (CRDS) along with specific VOCs (like isoprene, methanol, acetone etc.) measured at 10-Hz using Proton Transfer Reaction Mass Spectrometer - Eddy Covariance (PTRMS-EC) flux system. Spatially resolved eddy covariance fluxes were obtained using the virtual disjunct eddy covariance method and from Wavelet Analysis along flight tracks flown in the mixed layer. Preliminary analysis of mixing ratio measurements indicate that high concentrations of CH4 occur consistently while flying above the Central Valley that are correlated to large enhancements of methanol which is an important dairy and livestock emissions tracer. The elevated CH4 mixing ratios along the eastern edge of the San Joaquin Valley highlight the contribution of topography and emissions transport to local ambient levels of CH4. Large enhancements of CH4, benzene and toluene are also observed while flying over the oil production facilities in western part of Kern county (state's top oil producing county, 10% of US production) suggesting the likelihood of fugitive emissions in the region. VOC tracer analysis is used to evaluate the source of high CH4 emissions encountered along the eastern edge of the central Sacramento valley where fugitive emissions from natural gas fields and cultivation of rice are likely sources. Plumes from biomass burning, landfills and refineries encountered during different flights are also investigated. Eddy covariance based CH4 flux estimates are derived for various sources and compared with ';bottom-up' inventory estimates to verify/validate the CA methane inventory for major sources.

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

2013-12-01

5

Application of PMF in the Investigation of VOCs Emission Sources for Lake Champlain Basin  

NASA Astrophysics Data System (ADS)

Volatile Organic Compounds (VOCs) have long been considered hazardous atmospheric pollutants. VOCs account for the majority of the 188 air toxics species listed in the 1990 Clean Air Act (US). The National-Scale Air Toxics Assessment (NATA) Program established by EPA aims to coordinate national and state level efforts on concentration data collection, emission inventory, and population risk assessment. Like many other states, the State of Vermont established its Air Toxics Program which consists of seven monitoring sites, some of which started sample collection as early as 1993. This presentation focuses on an ongoing project to investigate emission sources of VOCs in the Lake Champlain Basin. Two monitoring sites, Burlington and Underhill sites were selected for their representation of two distinctly different urban and rural environments. Statistical methods including the Positive Matrix Factorization were employed. Identified likely sources, up to fourteen of them for each site, that are either common to both sites or unique to one of the two, as well as the apportionment results, will be discussed. In addition, the presentation will discuss particular challenges arisen in the source-receptor modeling processes due to low concentration levels of many VOCs, the absence of some very volatile species in the Vermont Air Toxics monitoring program, rapid chemical transformations or decompositions occurred during atmospheric transport of the VOCs, and the complexity and uncertainty in the emissions inventory.

Gao, N.; Anderson, K.; Poirot, R.

2009-04-01

6

Chemical composition of major VOC emission sources in the Seoul atmosphere.  

PubMed

This paper describes a chemical analysis of volatile organic compounds (VOCs) for five emission sources in Seoul. The source categories included motor vehicle exhaust, gasoline evaporation, paint solvents, natural gas and liquefied petroleum gas (LPG). These sources were selected because they have been known to emit significant quantities of VOCs in the Seoul area (more than 5% of the total emission inventory). Chemical compositions of the five emission sources are presented for a group of 45 C2-C9 VOCs. Motor vehicle exhaust profiles were developed by conducting an urban tunnel study. These emissions profiles were distinguished from the other emission profiles by a high weight percentage of butanes over seasons and propane in the wintertime. It was found that this is due to the wide use of butane-fueled vehicles. To obtain gasoline vapor profiles, gasoline samples from five major brands for each season were selected. The brands were blended on the basis of the marketshare of these brands in Seoul area. Raoult's law was used to calculate gasoline evaporative compositions based on the liquid gasoline compositions. The measured and estimated gasoline vapor compositions were found to be in good agreement. Vehicle and gasoline evaporation profiles were made over seasons because of the seasonal change in their compositions. Paint solvent emissions profiles were produced based on a product-use survey and sales figures. These profiles are a composite of four major oil-based paints and thinning solvent. The source profile of natural gas was made on a methane-free basis. It was found that Ethane and propane were the most abundant compounds accounting for 95% of the natural gas composition. LPG was largely composed of propane and ethane and the remaining components were minor contributors. PMID:15006511

Na, Kwangsam; Kim, Yong Pyo; Moon, Il; Moon, Kil-Choo

2004-04-01

7

Locating industrial VOC sources with aircraft observations.  

PubMed

Observation and characterization of environmental pollution, focussing on Volatile Organic Compounds (VOCs), in a high-risk industrial area, are particularly important in order to provide indications on a safe level of exposure, indicate eventual priorities and advise on policy interventions. The aim of this study is to use the Solid Phase Micro Extraction (SPME) method to measure VOCs, directly coupled with atmospheric measurements taken on a small aircraft environmental platform, to evaluate and locate the presence of VOC emission sources in the Marghera industrial area. Lab analysis of collected SPME fibres and subsequent analysis of mass spectrum and chromatograms in Scan Mode allowed the detection of a wide range of VOCs. The combination of this information during the monitoring campaign allowed a model (Gaussian Plume) to be implemented that estimates the localization of emission sources on the ground. PMID:21376441

Toscano, P; Gioli, B; Dugheri, S; Salvini, A; Matese, A; Bonacchi, A; Zaldei, A; Cupelli, V; Miglietta, F

2011-05-01

8

Source Apportionment of VOCs in Edmonton, Alberta  

NASA Astrophysics Data System (ADS)

Regional emissions at Edmonton, Alberta, are complex, containing emissions from (1) transportation sources, such as cars, trucks, buses, and rail; (2) industrial sources, such as petroleum refining, light manufacturing, and fugitive emissions from holding tanks or petroleum terminals; and (3) miscellaneous sources, such as biogenic emissions and natural gas use and processing. From 2003 to 2009, whole air samples were collected at two sites in Edmonton and analyzed for over 77 volatile organic compounds (VOCs). VOCs were sampled in the downtown area (Central) and the industrial area on the eastern side of the city (East). Concentrations of most VOCs were highest at the East site. The positive matrix factorization (PMF) receptor model was used to apportion ambient concentration measurements of VOCs into eleven factors, which were associated with emissions source categories. Factors of VOCs identified in the final eleven-factor solution include transportation sources (both gasoline and diesel vehicles), industrial sources, a biogenic source, and a natural-gas-related source. Transportation sources accounted for more mass at the Central site than at the East site; this was expected because Central is in a core urban area where transportation emissions are concentrated. Transportation sources accounted for nearly half of the VOC mass at the Central site, but only 6% of the mass at the East site. Encouragingly, mass from transportation sources has declined by about 4% a year in this area; this trend is similar to the decline found throughout the United States, and is likely due to fleet turnover as older, more highly polluting cars are replaced with newer, cleaner cars. In contrast, industrial sources accounted for ten times more VOC mass at the East site than at the Central site and were responsible for most of the total VOC mass observed at the East site. Of the six industrial factors identified at the East site, four were linked to petrochemical industry production and storage. The two largest contributors to VOC mass at the East site were associated with fugitive emissions of volatile species (butanes, pentanes, hexane, and cyclohexane); together, these two factors accounted for more than 50% of the mass at the East site and less than 2% of the mass at the Central site. Natural-gas-related emissions accounted for 10% to 20% of the mass at both sites. Biogenic emissions and VOCs associated with well-mixed global background were less than 10% of the VOC mass at the Central site and less than 3% of the mass at the East site. Controllable emissions sources account for the bulk of the identified VOC mass. Efforts to reduce ozone or particulate matter precursors or exposure to toxic pollutants can now be directed to those sources most important to the Edmonton area.

McCarthy, M. C.; Brown, S. G.; Aklilu, Y.; Lyder, D. A.

2012-12-01

9

VOC EMISSION CONTROL TECHNOLOGIES FOR SHIP PAINTING FACILITIES: INDUSTRY CHARACTERIZATION  

EPA Science Inventory

The U.S. Environmental Protection Agency has the responsibility of reducing the levels of VOC emissions from the nation's stationary and mobile sources. The project was directed at assessing the levels of VOC emissions from ship painting operations with the intent of determining ...

10

40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.  

Code of Federal Regulations, 2013 CFR

...Organic Compound (VOC) emissions from bulk gasoline terminals. 60.502 Section 60...SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for...Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the...

2013-07-01

11

VALIDATION OF VOC EMISSIONS INVENTORIES BY SOURCE APPORTIONMENT AND 14C DATING METHODS: PART 1  

EPA Science Inventory

This report brings together two conference papers and a journal article (published or in press) which collectively summarize work to date under work supported by the Joint Emissions Inventory oversight Group (JEIOG) to examine the utility of receptor modeling in the validation of...

12

Source apportionment of ambient VOCS in Mumbai city  

NASA Astrophysics Data System (ADS)

Air pollution kills almost half a million Asians every year. Most of this pollution is emitted from buses, trucks, motorcycles and other forms of transport. As Asia's cities continue to expand, the rising number of vehicles has resulted in even greater pollution. Amongst the measures available to control, vehicular emission was engine modification, catalytic converters and fuel modifications. Some of these have led to emissions of some hazardous air pollutants (HAP) like volatile organic compounds (VOCs). VOC emission is an area needing attention in air quality management. This paper discusses a study on VOC concentration at major sources like traffic junction, residential area, commercial areas, industrial areas and petrol pumps in Mumbai city. CMB8 Model has been used to apportion VOCs in Mumbai city. It was observed that evaporative emissions dominate in Mumbai. In order to control VOCs in air the management strategy should thus focus on cost effective vapor recovery systems at refueling stations and in vehicles. Effective inspection and maintenance programme can reduce evaporative and exhaust VOC emissions. Modifying certain fuel parameters, like reducing benzene content in petrol will as well reduce VOC content in air. The benzene content in petrol was 3% in the year 2001 in Mumbai. Adulteration also results in high levels of VOCs in air.

Srivastava, Anjali

13

VOC emission into the atmosphere by trees and leaf litter in Polish forests  

Microsoft Academic Search

It is generally recognized at present that the vegetation of continents is the principal source of reactive volatile organic compounds (VOC) of the atmosphere. The upper limit of the evaluation of global phytogenic VOC is 1100-1500 Tg\\/yr (Isidorov, 1990; Guenther et al., 1995). Although these global evaluations showing the place of phytogenic emission among of other VOC sources are important,

V. Isidorov; M. Smolewska; Z. Tyszkiewicz

2009-01-01

14

Emission characteristics of VOCs from athletic tracks.  

PubMed

Dynamic and flow-through flux chambers are convenient tools for field measurements of gas or VOC emission flux from solid surfaces in the field. This study was undertaken to collect on site and quantify the emissions of volatile organic compounds (VOCs) released from athletic running tracks. Three typical types of tracks, one synthetic rubber and two tracks (types I and II) consisting mainly of polyurethane, were studied. They were all installed with adhesives and backings, both of which contributed significant amount of VOCs. VOCs released from the track surface were collected with a flux chamber and subsequently analyzed by a gas chromatograph/mass spectrometer (GC/MS). Also, for each track and at each selected time the emission flux and mass emission were measured on site under outdoor conditions over a period of 40 min. GC/MS analyses show that the VOCs emitted include 2-methyl furan, butanal, methyl ethyl ketone, benzene, heptane, methyl isobutyl ketone, toluene+octane, hexanal, nonane+ethylbenzene, xylenes+styrene, propyl benzene, decane, 1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, 1,2, 3-trimethyl benzene and undecane. Of these, hexanal was the common and principal compound for all three types of tracks. 2-Methyl furan and methyl isobutyl ketone were the characteristic compounds for the synthetic rubber and the type II of polyurethane tracks, respectively. In the field studies, no unique compounds were found in the type I of polyurethane tracks. For each of these three types of tracks the total-VOCs emission flux was correlated to the track age and track surface temperature. The results of multiple regression analysis showed good correlation. The type II polyurethane track had the highest decay rate, while the synthetic rubber track had the lowest decay rate. Two years after the track installation, the VOC concentrations measured at 1.5 m above the track, the breathing height of school children, were not significantly higher than the background levels. PMID:10611425

Chang, F H; Lin, T C; Huang, C I; Chao, H R; Chang, T Y; Lu, C S

1999-12-23

15

Hot stuff controls for VOC emissions  

SciTech Connect

For close to three decades, American industry has paved the way and led the world in controlling volatile organic compound (VOC) emissions. As more and more systems have been installed, the history of operation for the various types of systems has broadened dramatically, spurring significant technological advances, the traditional technologies and those on the cutting edge of VOC control. With the number of technologies available, the environmental professional may have a difficult task choosing the most strategic environmental solution. The conventional, traditional or proven methodology for VOC control has been incineration. Other technologies have been used for very specific applications. In deciding the specific type of incineration system to select, the environmental professional will look at a broad spectrum of evaluation factors. These include initial system cost, operational cost, maintenance requirements, reliability factors and most importantly, the projected success of achieving 99% VOC destruction efficiency. This article provides an overview of the basic differences among incineration technologies.

Yewshenko, P. [Ross Air Systems, Somerville, NJ (United States)

1995-12-01

16

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

EPA Science Inventory

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

17

Reducing VOC Press Emission from OSB Manufacturing  

SciTech Connect

Current regulations require industry to meet air emission standards with regard to particulates, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and other gases. One of many industries that will be affected by the new regulations is the wood composites industry. This industry generates VOCs, HAPs, and particulates mainly during the drying and pressing of wood. Current air treatment technologies for the industry are expensive to install and operate. As regulations become more stringent, treatment technologies will need to become more efficient and cost effective. The overall objective of this study is to evaluate the use of process conditions and chemical additives to reduce VOC/HAPs in air emitted from presses and dryers during the production of oriented strand board.

Dr. Gary D. McGinnis; Laura S. WIlliams; Amy E. Monte; Jagdish Rughani: Brett A. Niemi; Thomas M. Flicker

2001-12-31

18

Evaluation of VOC emission and sorption characteristics of low-VOC adhesive-bonded building materials  

Microsoft Academic Search

To reduce the risk of indoor air pollution caused by synthetic building materials, low-volitile organic compounds (VOC) building materials, including adhesives, are commonly used in building construction. Although adhesives do not directly contact indoor air, they affect VOC mass transfer at the surface of finishing materials by diffusion. This study investigates VOC emission and sorption behaviors of building materials with

Dong Hwa Kang; Dong Hee Choi; Myoung Souk Yeo; Kwang Woo Kim

2012-01-01

19

A mass transfer model for VOC emission from silage  

NASA Astrophysics Data System (ADS)

Silage has been shown to be an important source of emissions of volatile organic compounds (VOCs), which contribute to the formation of ground-level ozone. Measurements have shown that environmental conditions and silage properties strongly influence emission rates, making it difficult to assess the contribution of silage in VOC emission inventories. In this work, we present an analytical convection-diffusion-dispersion model for predicting emission of VOCs from silage. It was necessary to incorporate empirical relationships from wind tunnel trials for the response of mass transfer parameters to surface air velocity and silage porosity. The resulting model was able to accurately predict the effect of temperature on ethanol emission in wind tunnel trials, but it over-predicted alcohol and aldehyde emission measured using a mass balance approach from corn silage samples outdoors and within barns. Mass balance results confirmed that emission is related to gas-phase porosity, but the response to air speed was not clear, which was contrary to wind tunnel results. Mass balance results indicate that alcohol emission from loose silage on farms may approach 50% of the initial mass over six hours, while relative losses of acetaldehyde will be greater.

Hafner, Sasha D.; Montes, Felipe; Rotz, C. Alan

2012-07-01

20

Measurements of biogenic VOC emissions: sampling, analysis and calibration  

NASA Astrophysics Data System (ADS)

We describe an experimental system and techniques for sampling and analyzing biogenic emissions of volatile organic compounds (VOC). The system uses a Teflon chamber to enclose a single branch of a tree. Temperature, photosynthetic active radiation (PAR), relative humidity and carbon dioxide concentration are continuously monitored with a time resolution of five minutes. VOCs are sampled on tubes containing solid adsorbents (Tenax TA and Carbotrap) with a time resolution of 1 h. Composition and concentration of VOC emissions are measured with a gas chromatographic system equipped with a flame ionization detector (FID) for quantitative and a mass spectrometer (MS) for qualitative analysis. To calibrate the system, a diffusion source was built to produce standard mixtures of up to 36 different compounds with mixing ratios at low concentrations and high accuracy. The diffusion rates were monitored over 17 months and showed variations between 0.2 and 7.6% for monoterpenes (expect for ?-phellandrene, ?-terpinene and ?-terpinene) and between 10.6 and 22.6% for sesquiterpenes. FID response factors calculated from calibration measurements were corrected using correction factors based on the effective carbon number concept. The individual response factors of 23 compounds were combined to a mean response factor (RF m) with a value of 23,100 ?V s ng -1 and a standard deviation of 9%. The system described here was used to measure VOC emission rates of Scots pine ( Pinus sylvestris) in 1998 and 1999.

Komenda, M.; Parusel, E.; Wedel, A.; Koppmann, R.

21

Volatile organic compound (VOC) emissions from soil and litter samples  

Microsoft Academic Search

The production of nonmethane volatile organic compounds (VOCs) by soil microbes is likely to have an important influence on soil ecology and terrestrial biogeochemistry. However, soil VOC production has received relatively little attention, and we do not know how the emissions of microbially-produced VOCs vary across soil and litter types. We collected 40 root-free soil and litter samples from a

Jonathan W. Leff; Noah Fierer

2008-01-01

22

Source Test Measurement of Nitrogen Oxides, Sulfur Dioxide, Carbon Monoxide, VOC, and PM10 Emissions on Gas Turbine Number 2 at Onizuka AFB, California.  

National Technical Information Service (NTIS)

Sampling was conducted to measure the following contaminant output from one of twelve gas turbines located at the Onizuka AFB Power Plant: NOy, SO2, CO, VOC, PM10. The results will be used to determine the banking and selling of emission credits upon curt...

S. H. Brown

1994-01-01

23

VOC (VOLATILE ORGANIC COMPOUND EMISSION FACTORS FOR THE NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSION INVENTORY  

EPA Science Inventory

The report gives results of the generation of emission factors for volatile organic compound (VOC) emissions for a number of source classification categories (SCCs), as part of the National Acid Precipitation Assessment Program (NAPAP). Each SCC represents a process or function t...

24

VOC signatures from North American oil and gas sources (Invited)  

NASA Astrophysics Data System (ADS)

Between 2008 and 2013 UC Irvine has used its whole air sampling (WAS) technique to investigate VOC source signatures from a range of oil and gas sources in North America, including five separate field campaigns at the Alberta oil sands (1 airborne, 4 ground-based); the 2010 Deepwater Horizon oil spill (airborne and ship-based); the 2012 airborne Deep Convective Clouds and Chemistry Project (DC3) mission over oil and gas wells in Colorado, Texas and Oklahoma; and the 2013 ground-based Barnett Shale Campaign in Texas. Each campaign has characterized more than 80 individual C1-C10 VOCs including alkanes, alkenes and aromatics. For example, oil sands are an extra-heavy, unconventional crude oil that is blended with diluent in order to flow, and upgraded into synthetic crude oil. The VOC signature at the oil sands mining and upgrading facilities is alkane-rich, and the fuel gas associated with these operations has an i-butane/n-butane ratio similar to that of liquefied petroleum gas (LPG). In addition to light alkanes, enhanced levels of benzene were observed over US oil and natural gas wells during DC3, likely because of its use in hydrofracking fluid. A series of VOC emission ratios from North American petrochemical sources will be presented and compared, including oil sands, conventional oil and hydrofracking operations.

Simpson, I. J.; Marrero, J.; Blake, N. J.; Barletta, B.; Hartt, G.; Meinardi, S.; Schroeder, J.; Apel, E. C.; Hornbrook, R. S.; Blake, D. R.

2013-12-01

25

Odorous VOC emission following land application of swine manure slurry  

NASA Astrophysics Data System (ADS)

Swine manure is often applied to crop land as a fertilizer source. Odor emissions from land-applied swine manure may pose a nuisance to downwind populations if manure is not applied with sufficient forethought. A research project was conducted to assess the time decay of odorous volatile organic compound (VOC) emissions following land application of swine manure. Three land application methods were compared: surface application, incorporation 24 h after surface application, and injection. Emission rates were measured in field plots using a small wind tunnel and sorbent tubes. VOCs including eight volatile fatty acids, five aromatics, and two sulfur-containing compounds were quantified by gas chromatography-mass spectrometry. In most cases, a first order exponential decay model adequately described the flux versus time relationship for the 24 h period following land application, but the model sometimes overestimated flux in the 6-24 h range. The same model but with the time term squared adequately predicted flux over the entire 24 h period. Three compounds (4-methylphenol, skatole, and 4-ethylphenol) accounted for 93 percent of the summed odor activity value. First order decay constants (k) for these three compounds ranged from 0.157 to 0.996 h-1. When compared to surface application, injection of swine manure resulted in 80-95 percent lower flux for the most odorous aromatic compounds. These results show that VOC flux decreases rapidly following land application of swine manure, declining below levels of detection and near background levels after 4 to 8 h.

Parker, David B.; Gilley, John; Woodbury, Bryan; Kim, Ki-Hyun; Galvin, Geordie; Bartelt-Hunt, Shannon L.; Li, Xu; Snow, Daniel D.

2013-02-01

26

Pilot and Full Scale Measurements of VOC Emissions from Lumber Drying of Inland Northwest Species  

SciTech Connect

Volatile organic compounds (VOCs) are precursors to ground level ozone. Ground level ozone is the major component of photochemical smog, and has been linked to a variety of adverse health effects. These health effects include cancer, heart disease, pneumonia and death. In order to reduce ground level ozone, VOC emissions are being more stringently regulated. One VOC source that may come under regulation is lumber drying. Drying lumber is known to emit VOC into the atmosphere. This research evaluates the validity of VOC emission measurements from a small-scale kiln to approximate VOC emissions from kilns at commercial mills. We also report emission factors for three lumber species commonly harvested in the northwest United States (Douglas-fir, ponderosa pine, & grand fir). This work was done with a novel tracer ratio technique at a small laboratory kiln and a large commercial lumber drying facility. The measured emission factors were 0.51 g/kgOD for Douglas-fir, 0.7 g/kgOD for ponderosa pine, and 0.15 g/kgOD for grand fir. Aldehyde emission rates from lumber drying were also measured in some experiments. Results indicate that aldehyde emissions can constitute a significant percentage of the total VOC emissions.

Fritz, Brad G.; Lamb, Brian K.; Westberg, Halvor; Folk, Richard; Knighton, B; Grimsrud, E

2004-07-01

27

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

SciTech Connect

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

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

2002-01-01

28

SUBSTRATE EFFECTS ON VOC EMISSIONS FROM A LATEX PAINT  

EPA Science Inventory

The effects of two substrates -- a stainless steel plate and a gypsum board -- on the volatile organic compound (VOC) emissions from a latex paint were evaluated by environmental chamber tests. It was found that the amount of VOCs emitted from the painted stainless steel was 2 to...

29

Biofiltration: An Innovative Air Pollution Control Technology For VOC Emissions  

Microsoft Academic Search

Biofiltration is a relatively recent air pollution control (APC) technology in which off-gases containing biodegradable volatile organic compounds (VOC) or inorganic air toxics are vented through a biologically active material. This technology has been successfully applied in Germany and The Netherlands in many full-scale applications to control odors, VOC and air toxic emissions from a wide range of industrial and

Gero Leson; Arthur M. Winer

1991-01-01

30

Determination of Summertime VOC Emission Rates from Produced Water Ponds in the Uintah Basin  

NASA Astrophysics Data System (ADS)

The observance of excess ozone concentrations in Utah's Uintah Basin over past several years has prompted several investigations into the extent and causes of the elevated ozone. Among these is the assessment of potential emissions of reactive VOCs. Evaporation ponds, used a remediation technique for treatment of contaminated production and other waters, are one potential source of significant VOC emissions and is estimated that there are around 160 such ponds within the Uintah Basin's oil and gas production areas. In June 2012 VOC emission rates for several reactive VOCs were derived for an evaporation facility consisting of a small inlet pond (?0.03 acres) and two larger, serial ponds (?4.3 acres each). The emission rates were determined over three sampling periods using an inverse modeling approach. Under this methodology, ambient VOC concentrations are determined at several downwind locations through whole-air collection into SUMMA canisters, followed by GC/MS quantification and compared with predicted concentrations using an EPA-approved dispersion model, AERMOD. The presumed emission rates used within the model were then adjusted until the modeled concentrations approach the observed concentrations. The derived emission rates for the individual VOCs were on the order of 10-3 g/s/m2 from the inlet pond and 10-6 g/s/m2 from the larger ponds. The emissions from the 1st pond in series after the inlet pond were about 3-4x the emissions from the 2nd pond. These combined emission rates are about an order of magnitude those reported for a single study in Colorado (Thoma, 2009). It should be noted, however, that the variability about each of the VOC emission rates was significant (often ×100% at the 95% confidence interval). Extrapolating these emission rates to the estimated total areas of all the evaporation ponds within Basin resulted in calculated Basin-wide VOC emissions 292,835 tons/yr. However, Bar-Ilan et al. (2009) estimated 2012 VOC oil and gas related emissions within the Uintah Basin to be 119,974 tons/yr. Given the large observed variabilities and the uncertainties with extrapolating the derived emission rates across varying pond types and differing climatic conditions, the comparisons are not unreasonable. If the lower, literature emission rates of Thoma (2009) are used the estimated Basin-wide evaporation emissions, the pond emissions would still be approximately 30% of the total emissions compiled by Bar-Ilan et al. (2009). Although the study described herein only represents a single facility and a single set of seasonal conditions, extrapolating these rates can give potential insight into the significance of VOC emissions into the Basin atmosphere from evaporation ponds.

Martin, R. S.; Woods, C.; Lyman, S.

2013-12-01

31

Quantifying VOC emissions for the strategic petroleum reserve.  

SciTech Connect

A very important aspect of the Department of Energy's (DOE's) Strategic Petroleum Reserve (SPR) program is regulatory compliance. One of the regulatory compliance issues deals with limiting the amount of volatile organic compounds (VOCs) that are emitted into the atmosphere from brine wastes when they are discharged to brine holding ponds. The US Environmental Protection Agency (USEPA) has set limits on the amount of VOCs that can be discharged to the atmosphere. Several attempts have been made to quantify the VOC emissions associated with the brine ponds going back to the late 1970's. There are potential issues associated with each of these quantification efforts. Two efforts were made to quantify VOC emissions by analyzing VOC content of brine samples obtained from wells. Efforts to measure air concentrations were mentioned in historical reports but no data have been located to confirm these assertions. A modeling effort was also performed to quantify the VOC emissions. More recently in 2011- 2013, additional brine sampling has been performed to update the VOC emissions estimate. An analysis of the statistical confidence in these results is presented here. Arguably, there are uncertainties associated with each of these efforts. The analysis herein indicates that the upper confidence limit in VOC emissions based on recent brine sampling is very close to the 0.42 ton/MMB limit used historically on the project. Refining this estimate would require considerable investment in additional sampling, analysis, and monitoring. An analysis of the VOC emissions at each site suggests that additional discharges could be made and stay within current regulatory limits.

Knowlton, Robert G.; Lord, David L.

2013-06-01

32

CONTROL TECHNOLOGIES FOR FUGITIVE VOC EMISSIONS FROM CHEMICAL PROCESSES  

EPA Science Inventory

This handbook contains information concerning volatile organic compound (VOC) emissions from the synthetic organic chemicals manufacturing industry (SOCMI), petroleum refineries, on-shore natural gas processing plants, polymer manufacturing plants, benzene from particular equipme...

33

Locating industrial VOC sources with aircraft observations  

Microsoft Academic Search

Observation and characterization of environmental pollution, focussing on Volatile Organic Compounds (VOCs), in a high-risk industrial area, are particularly important in order to provide indications on a safe level of exposure, indicate eventual priorities and advise on policy interventions. The aim of this study is to use the Solid Phase Micro Extraction (SPME) method to measure VOCs, directly coupled with

P. Toscano; B. Gioli; S. Dugheri; A. Salvini; A. Matese; A. Bonacchi; A. Zaldei; V. Cupelli; F. Miglietta

2011-01-01

34

VOC Source and Inflow Characterization during the Deep Convective Cloud and Chemistry (DC3) experiment  

NASA Astrophysics Data System (ADS)

More than 50 volatile organic compounds (VOCs) were measured during the Deep Convective Clouds and Chemistry Project (DC3) field campaign, which was based out of Salina, KS May 10 - June 30, 2012. DC3 investigated the impact of deep, mid-latitude continental convective clouds on upper tropospheric composition and chemistry. The UCI Whole Air Sampler (WAS) measured VOCs on board the NASA DC-8 aircraft and the NCAR Trace Organic Gas Analyzer (TOGA) measured VOCs on board the NSF GV. Coordinated flights between the two aircraft produced a rich dataset with which to characterize the inflow and outflow of convective events. While probing storm inflow, numerous natural and anthropogenic sources were encountered, including oil and gas wells in Colorado, Texas, and Oklahoma, biomass burning, biogenic VOC emissions, and other anthropogenic sources (urban, feedlots, etc). The significant and widespread influence of oil and gas activities dominated VOC alkane distributions during DC3, in both inflow and outflow, effectively illustrating the connection between emission and fast vertical transport of VOCs into the free troposphere. We present a mass balance analysis of a flight over TX and OK, which allowed us to estimate oil and gas emissions in that region. The results from this analysis will be compared to previous work in the same area, as well as to emissions from other oil and gas regions and to model simulations from the Community Atmosphere Model with Chemistry (CAM-chem).

Blake, N. J.; Hartt, G.; Barletta, B.; Simpson, I. J.; Schroeder, J.; Hung, Y.; Marrero, J.; Gartner, A.; Hirsch, C.; Meinardi, S.; Blake, D. R.; Zhang, Y.; Apel, E. C.; Hornbrook, R. S.; Campos, T. L.; Emmons, L. K.

2013-12-01

35

Estimation of Biogenic VOC Emissions From Ecosystems in the Czech Republic  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOC) are one of the crucial elements in photochemical reactions in the atmosphere which lead to tropospheric ozone formation. While modelling concentration of low-level ozone proper information about VOC sources and sinks is necessary. VOC are emitted into the atmosphere both from anthropogenic and natural sources. It has been shown in previous studies (e.g. Simpson et al, 1995) that contribution of volatile organic compounds emitted from biogenic sources to total amount of VOC in the atmosphere can be significant. Our work focuses on estimation of VOC emissions from natural ecosystems, most importantly from forests, and its application in photochemical modelling. Preliminary results have shown that inclusion of biogenic emissions in model input data leads to improvement of resulting ozone concentration which encouraged us to work on detailed biogenic VOC emission estimation. Using grid of 1x1km CORINE Land Cover over the area of the Czech Republic, emissions from deciduous, coniferous and mixed forests were estimated aplying the algorithm of Guenther et al., 1995. According to data from Forest Management Institute each cell of model grid has been assigned a proportional composition of each of thirteen tree species which are the the main forest constituents in the Czech Republic. Aggregating data of tree species composition with land cover category emission factor of particular chemical compound (isoprene, monoterpenes) has been obtained for each cell. Annual emissions of VOC on hourly basis have been calculated for domain of the Czech Republic. Biogenic emissions of isoprene and monoterpenes were compared with the emission inventory of anthropogenic sources. The inventory is provided by Czech Hydrometeorological Institute and covers emissions from major stationary sources, area sources (including domestic heating) and mobile sources. Our results show that natural emissions are approximately half the amount of organic compounds emitted from anthropogenic sources. References: - Simpson D., Guenther A., Hewit C.N. and Steinbrecher R., 1995. Biogenic emissions in Europe. 1. estimates and uncertainties. J. Geophys. Res. 100(D11), 22875-22890. - Guenther A., Hewitt N., Erickson D., Fall R., Geron Ch., Graedel T., Harley P., Klinger L., Lerdau M., McKay W. A., Pierce T., Scholes B., Steinbrecher R., Tallamraju R., Taylor J., Zimmerman P., 1995. Global model of natural organic compound emissions. J. Geophys. Res. 100, 8873-8892.

Zemankova, K.; Brechler, J.

2008-12-01

36

Exploring VOC control options  

Microsoft Academic Search

Since the refineries and chemical plants handle large quantities of volatile organic compounds (VOCs), some emissions of these compounds are likely during normal operations. Based on studies in the US, the largest source of VOCs is from fugitive emissions from piping and other fluid handling components. VOCs also come from storage tanks, loading operations, and wastewater treatment. The most applicable

Siegell

1996-01-01

37

Effects of NO x and VOCs from five emission sources on summer surface O3 over the Beijing-Tianjin-Hebei region  

NASA Astrophysics Data System (ADS)

The impacts of emissions from industry, power plant, transportation, residential, and biogenic sources on daily maximum surface ozone (O3DM) over the Beijing-Tianjin-Hebei (BTH) region in North China in the summer of 2007 were examined in a modeling study. The modeling system consisted of the Weather Research and Forecasting (WRF) model and the photochemical dispersion model, CAMx. The factor separation technique (FST) was used to quantify the effect of individual emission source types and the synergistic interactions among two or more types. Additionally, the effectiveness of emission reduction scenarios was explored. The industry, power plant, and transportation emission source types were found to be the most important in terms of their individual effects on O3DM. The key contributor to high surface O3 was power plant emissions, with a peak individual effect of 40 ppbv in the southwestern BTH area. The individual effect from the biogenic emission category was quite low. The synergistic effects from the combinations of each pair of anthropogenic emission types suppressed O3 formation, while the synergistic effects for combinations of three were favorable for O3 formation when the industrial and power plant emission source types coexisted. The quadruple synergistic effects were positive only with the combination of power plant, transportation, residential, and biogenic sources, while the quintuple synergistic effect showed only minor impacts on O3DM concentrations. A 30% reduction in industrial and transportation sources produced the most effective impacts on O3 concentrations, with a maximum decrease of 20 ppbv. These results suggested that the synergistic impacts among emission source types should be considered when formulating emission control strategies for O3 reduction.

Qu, Yu; An, Junling; Li, Jian; Chen, Yong; Li, Ying; Liu, Xingang; Hu, Min

2014-07-01

38

Modeling the VOC emissions from interior latex paint applied to gypsum board  

SciTech Connect

The paper discusses modeling volatile organic compound (VOC) emissions from indoor latex paint applied to gypsum board. An empirical source model for a porous substrate was developed that takes both the wet- and dry-stage emission into consideration. Tests in the U.S. EPA`s Source Characterization Laboratory showed that common interior surfaces such as gypsum board and carpet could absorb significant amounts of latex paint VOCS from the air, and that they were re-emitted very slowly. An indoor air quality model incorporating the source model, an irreversible sink model, and the air movement data obtained from tracer gas tests made satisfactory predictions for the VOC levels in a test house.

Guo, Z.; Fortmann, R.; Marfiak, S.; Tichenor, B.; Sparks, L.

1997-09-01

39

Detection and quantification of methane and VOC emissions from oil and gas production operations using remote measurements, Interim report  

EPA Science Inventory

Improved understanding of air pollutant emissions from oil and gas production operations is needed. With a steadily increasing number of production sources, the impact of emitted volatile organic compounds (VOCs) on regional ozone is potentially significant. As the separation dis...

40

Speciated VOC emission inventory and spatial patterns of ozone formation potential in the Pearl River Delta, China.  

PubMed

The Pearl River Delta region (PRD) of China has long suffered from severe ground-level ozone pollution. Knowledge of the sources of volatile organic compounds (VOCs) is essential for ozone chemistry. In this work, a speciated VOC emission inventory was established on the basis of updated emissions and local VOC source profiles. The top 10 species, in terms of ozone formation potentials (OFPs), consisted of isoprene, mp-xylene, toluene, ethylene, propene, o-xylene, 1,2,4-trimethylbenzene, 2-methyl-2-butene, 1-butene, and alpha-pinene. These species contributed only 35.9% to VOCs emissions but accounted for 64.1% of the OFP in the region. The spatial patterns of the VOC source inventory agreed well with city-based source apportionment results, especially for vehicle emissions and industry plus VOC product-related emissions. Mapping of the OFPs and measured ozone concentrations indicated that the formation of higher ozone in the south and southeast of the PRD region differed from that in the Conghua area, a remote area in the north of the PRD. We recommend that the priorities for the control of VOC sources include motorcycles, gasoline vehicles, and solvent use because of their larger OFP contributions. PMID:20028055

Zheng, Junyu; Shao, Min; Che, Wenwei; Zhang, Lijun; Zhong, Liuju; Zhang, Yuanhang; Streets, David

2009-11-15

41

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 9. QUALITY ASSURANCE  

EPA Science Inventory

Radian Corporation, under contract to the U.S. Environmental Protection Agency, performed site selection, test plan development, and performance tests of catalytic incinerators used for volatile organic compound (VOC) emissions control at industrial sites. VOC emissions are of co...

42

Light dependency of VOC emissions from selected Mediterranean plant species  

NASA Astrophysics Data System (ADS)

The light, temperature and stomatal conductance dependencies of volatile organic compound (VOC) emissions from ten plant species commonly found in the Mediterranean region were studied using a fully controlled leaf cuvette in the laboratory. At standard conditions of temperature and light (30°C and 1000 ?mol m -2 s -1 PAR), low emitting species ( Arbutus unedo, Pinus halepensis, Cistus incanus, Cistus salvifolius, Rosmarinus officinalis and Thymus vulgaris) emitted between 0.1 and 5.0 ?g (C) (total VOCs) g -1 dw h -1, a medium emitter ( Pinus pinea) emitted between 5 and 10 ?g (C) g -1 dw h -1 and high emitters ( Cistus monspeliensis, Lavendula stoechas and Quercus sp.) emitted more than 10 ?g (C) g -1 dw h -1. VOC emissions from all of the plant species investigated showed some degree of light dependency, which was distinguishable from temperature dependency. Emissions of all compounds from Quercus sp. were light dependent. Ocimene was one of several monoterpene compounds emitted by P. pinea and was strongly correlated to light. Only a fraction of monoterpene emissions from C. incanus exhibited apparent weak light dependency but emissions from this plant species were strongly correlated to temperature. Data presented here are consistent with past studies, which show that emissions are independent of stomatal conductance. These results may allow more accurate predictions of monoterpene emission fluxes from the Mediterranean region to be made.

Owen, S. M.; Harley, P.; Guenther, A.; Hewitt, C. N.

43

VOC emission into the atmosphere by trees and leaf litter in Polish forests  

NASA Astrophysics Data System (ADS)

It is generally recognized at present that the vegetation of continents is the principal source of reactive volatile organic compounds (VOC) of the atmosphere. The upper limit of the evaluation of global phytogenic VOC is 1100-1500 Tg/yr (Isidorov, 1990; Guenther et al., 1995). Although these global evaluations showing the place of phytogenic emission among of other VOC sources are important, evaluations for individual countries are also very important. This poster represents the results of the estimation of VOC emission from Polish forests. Calculations took into account the composition and age of forests. According to our estimation, the total VOC emission by the arboreal vegetation differs from 190 to 750 kt/yr, depending of weather conditions in different years. There are only few studies conducted on decaying plant material as a source of atmospheric VOCs, but still they are able to give evidence of the importance of this source. For Polish forests, the litter mass is estimated to be (16-19)?106 t/yr. These organic materials undergo decomposition by mesofauna and microorganisms. In these processes volatile organic compounds (VOC) stored in the litter and secondary metabolites of litter-destroying fungi are emitted into the atmosphere. The scale of the phenomenon makes leaf litter an important VOC source in the atmosphere. The filling of numerous gaps in researches of VOC emissions from decomposing leaf litter demands carrying out of long term field experiments in various climatic conditions. In this communication we report also the results of 3.5-year experiment on qualitative and quantitative GC-MS investigations of VOC emitted into the gas phase from leaves litter of some species of deciduous and coniferous trees of Polish forests. Apart from terpenes and their oxygenated derivatives, which are usual in plant tissues, leaf litter intensively emits vast amounts of lower alcohols and carbonyl compounds. We suppose that these volatile substances are products of vital activity of fungi which decompose leaf litter. Verification of the hypothesis was carried out in the frames of a long-term experiment on decomposition of Scots pine and common spruce litter. The experiment was conducted in natural conditions by placing litter bags on undisturbed topsoil in a forest area where pine and spruce trees prevailed. Part of the needles placed were taken out of the litter bags on the 30th, 282nd, 490th, 630th and 920th day of the experiment for subsequent isolation of fungi which colonize the litter (overall there were identified 98 species which belong to 48 genera of fungi). The experiment revealed that species composition of the fungi colonizing pine and spruce litter varies considerably. At the early stages of decomposition, dematiceous hypnomycetes, which belongs to Cladosporum, Alternaria genera as well as Hormonem genus, capable of utilizing pectin, were dominant species. At the later stages they were substituted with phycomycetes (Mucor sp.), ascomycetes (Penicillium sp.) and basidiomycetes (Trichderma sp.), the most significant group of "secondary saprophytes" able to carry out biodegradation of polysaccharides and lignin. In volatile emissions of all the 15 species of fungi there were identified 80 VOCs of different classes: terpene hydrocarbons and their oxygenated derivatives, C6-C14 aliphatic and C6-C10 aromatic hydrocarbons, C1-C8 alcohols, C2-C9 carbonyls, esters, furans, and halocarbons. VOC composition was specific for each fungi species and depended on the litter of a particular tree species from which it had been isolated. For instance, the emission rate of terpenes, alcohols and carbonyl compounds by Trichoderma polysporum isolated from pine and spruce litter was 3-5 times different. Differences in composition of VOCs emitted into the gas phase by "primary" and "secondary" fungi species which colonize pine and spruce litter are also discussed. This work was supported by Grant MNiSW N305 067 32/2411.

Isidorov, V.; Smolewska, M.; Tyszkiewicz, Z.

2009-04-01

44

Application of microwave energy in the control of DPM, oxides of nitrogen and VOC emissions  

NASA Astrophysics Data System (ADS)

The emissions of DPM (diesel particulate matter), NOx (oxides of nitrogen), and toxic VOCs (volatile organic compounds) from diesel engine exhaust gases and other sources such as chemical process industry and manufacturing industry have been a great environmental and health concern. Most control technologies for these emissions require elevated temperatures. The use of microwave energy as a source of heat energy, however, has not been fully explored. In this study, the microwave energy was used as the energy source in three separate emission control processes, namely, the regeneration of diesel particulate filter (DPF) for DPM control, the NOx reduction using a platinum catalyst, and the VOC destruction involving a ceramic based material. The study has demonstrated that microwave heating is an effective method in providing heat for the studied processes. The control efficiencies associated with the microwave-assisted processes have been observed to be high and acceptable. Further research, however, is required for the commercial use of these technologies.

Pallavkar, Sameer M.

45

Primary VOC emissions from Commercial Aircraft Jet Engines  

NASA Astrophysics Data System (ADS)

Air traffic is growing continuously [1]. The increasing number of airplanes leads to an increase of aviation emissions giving rise to environmental concerns globally by high altitude emissions and, locally on air quality at the ground level [2]. The overall impact of aviation emissions on the environment is likely to increase when the growing air transportation trend [2] is considered. The Aviation Particle Regulatory Instrumentation Demonstration Experiment (APRIDE)-5 campaign took place at Zurich Airport in 2013. In this campaign, aircraft exhaust is sampled during engine acceptance tests after engine overhaul at the facilities of SR Technics. Direct sampling from the engine core is made possible due to the unique fixed installation of a retractable sampling probe and the use of a standardized sampling system designed for the new particulate matter regulation in development for aircraft engines. Many of the gas-phase aircraft emissions, e.g. CO2, NOX, CO, SO2, hydrocarbons, and volatile organic compounds (VOC) were detected by the instruments in use. This study, part of the APRIDE-5 campaign, focuses on the primary VOC emissions in order to produce emission factors of VOC species for varying engine operating conditions which are the surrogates for the flight cycles. Previously, aircraft plumes were sampled in order to quantify VOCs by a proton transfer reaction quadrupole mass spectrometer (PTR-MS) [3]. This earlier study provided a preliminary knowledge on the emission of species such as methanol, acetaldehyde, acetone, benzene and toluene by varying engine thrust levels. The new setup was (i) designed to sample from the diluted engine exhaust and the new tool and (ii) used a high resolution time of flight PTR-MS with higher accuracy for many new species, therefore providing a more detailed and accurate inventory. We will present the emission factors for species that were quantified previously, as well as for many additional VOCs detected during the campaign. References 1."Annual Review 2013", International Air Transport Association (IATA) 2014, Page 8, available on: http://www.iata.org/about/Documents/iata-annual-review-2013-en.pdf. 2."Summary for Policymakers: IPCC Special Report Aviation and the Global Atmosphere", 1999, pp. 5-10. 3."Hydrocarbon emissions from in-use commercial aircraft during airport operations", Herndon S.C., Rogers T., Dunlea E.J., Jayne J.T., Miake-Lye R., Knighton B., Environ Sci. Technol. 2006 Jul 15;40(14):4406-13.

Kilic, Dogushan; Huang, Rujin; Slowik, Jay; Brem, Benjamin; Durdina, Lukas; Rindlisbacher, Theo; Baltensperger, Urs; Prevot, Andre

2014-05-01

46

AN ALTERNATIVE METHOD FOR ESTIMATING BIOGENIC VOC EMISSIONS IN EPA REGION I  

EPA Science Inventory

Regional estimates of biogenic volatile organic compound (VOC) emissions are needed for computer simulations of photochemical smog. ince forests and agricultural crops are the primary emitters of biogenic voc, it is important to develop reliable estimates of their areal coverage ...

47

VOC source identification from personal and residential indoor, outdoor and workplace microenvironment samples in EXPOLIS-Helsinki, Finland  

NASA Astrophysics Data System (ADS)

Principal component analyses (varimax rotation) were used to identify common sources of 30 target volatile organic compounds (VOCs) in residential outdoor, residential indoor and workplace microenvironment and personal 48-h exposure samples, as a component of the EXPOLIS-Helsinki study. Variability in VOC concentrations in residential outdoor microenvironments was dominated by compounds associated with long-range transport of pollutants, followed by traffic emissions, emissions from trees and product emissions. Variability in VOC concentrations in environmental tobacco smoke (ETS) free residential indoor environments was dominated by compounds associated with indoor cleaning products, followed by compounds associated with traffic emissions, long-range transport of pollutants and product emissions. Median indoor/outdoor ratios for compounds typically associated with traffic emissions and long-range transport of pollutants exceeded 1, in some cases quite considerably, indicating substantial indoor source contributions. Changes in the median indoor/outdoor ratios during different seasons reflected different seasonal ventilation patterns as increased ventilation led to dilution of those VOC compounds in the indoor environment that had indoor sources. Variability in workplace VOC concentrations was dominated by compounds associated with traffic emissions followed by product emissions, long-range transport and air fresheners. Variability in VOC concentrations in ETS free personal exposure samples was dominated by compounds associated with traffic emissions, followed by long-range transport, cleaning products and product emissions. VOC sources in personal exposure samples reflected the times spent in different microenvironments, and personal exposure samples were not adequately represented by any one microenvironment, demonstrating the need for personal exposure sampling.

Edwards, Rufus D.; Jurvelin, J.; Koistinen, K.; Saarela, K.; Jantunen, M.

48

Multiscale analysis of satellite-derived vegetation parameters for biogenic VOC emission modeling  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOC) emitted by vegetation play an important role in atmospheric chemistry contributing to tropospheric ozone and secondary organic aerosol formation. Quantification of biogenic VOC may be performed using emission modeling tools that require information on vegetation dynamics. For this purpose satellite-derived parameters such as Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) are considered. However, spatial resolution of the satellite data could be an important source of uncertainties in biogenic VOC quantification. The main objective of the current study is to accomplish a sensitivity analysis of the biogenic emission modeling to the changes in data resolution of the satellite-derived vegetation parameters. This study is performed for an area of 80x 80km2 in Portugal for 2011. Satellite observations provided by DEIMOS-1 (22 m resolution) and MODIS (250m and 1000m resolution) are analyzed for NDVI and LAI. Also, meteorological data from the Weather Research and Forecasting (WRF) model and detailed land cover data are considered by the emission quantification algorithm. Multi-scale analysis of LAI and NDVI was performed. Also, the modeling results are analyzed in terms of spatial and temporal variations of the emissions. The results confirm high sensitivity of the emission model to spatial resolution of the satellite-derived data resulting in about 30% difference in total isoprene emissions for the study area.

Silveira, Carlos; Tchepel, Oxana

2013-08-01

49

The characteristics, seasonal variation and source apportionment of VOCs at Gongga Mountain, China  

NASA Astrophysics Data System (ADS)

The mixing ratio, composition and variability of volatile organic compounds (VOCs) were measured from 2008 through 2011 at Gongga Mountain Forest Ecosystem Research Station (102°00?E, 29°33?N, elevation 1640 m), a remote station in southwest China. Weekly samples were collected in the Gongga Mountain area and were analyzed using a three-stage preconcentration method coupled with GC–MS. An advance receptor model positive matrix factorization (PMF) was applied to identify and apportion the sources of VOCs. The results show that the measured VOC mixing ratio at Gongga Mountain is dominated by aromatics (35.7%) and alkanes (30.8%), followed by halocarbons (21.6%) and alkenes (11.9%). The general trend of seasonal variation shows higher mixing ratios in spring and lower mixing ratios in autumn. The effect of alkanes and aromatics on the seasonal variation of total volatile organic compounds (TVOCs) is significant. Five sources were resolved by the PMF model: (1) gasoline-related emission (the combination of gasoline exhaust and gas vapor), which contributes 35.1% of the measured VOC mixing ratios; (2) solvent use, contributing 21.8%; (3) fuel combustion, contributing 29.1%; (4) biogenic emission, contributing 5.2%; and (5) industrial, commercial and domestic sources, contributing 8.7%. The effect on this area of the long-range transport of air pollutants from highly polluted areas is significant.

Zhang, Junke; Sun, Yang; Wu, Fangkun; Sun, Jie; Wang, Yuesi

2014-05-01

50

Diffusion-controlled toluene reference material for VOC emissions testing: international interlaboratory study.  

PubMed

The measurement of volatile organic compound (VOC) emissions from building products and materials by manufacturers and testing laboratories, and the use of the test results for labeling programs, continue to expand. One issue that hinders wide acceptance for chamber product testing is the lack of a reference material to validate test chamber performance. To meet this need, the National Institute of Standards and Technology (NIST) and Virginia Tech (VT) have developed a prototype reference material that emits a single VOC similar to the emissions of a diffusion-controlled building product source with a dynamic emissions profile. The prototype material has undergone extensive testing at NIST and a pilot interlaboratory study (ILS) with four laboratories. The next development step is an evaluation of the prototype source in multiple-sized chambers of 14 laboratories in seven countries. Each laboratory was provided duplicate specimens and a test protocol. Study results identified significant issues related to the need to store the source at a subzero Celsius temperature until tested and possible inconsistencies in large chambers. For laboratories using a small chamber and meeting all the test method criteria, the results were very encouraging with relative standard deviations ranging from 5% to 10% across the laboratories. Implications: Currently, the chamber performance of laboratories conducting product VOC emissions testing is assessed through interlaboratory studies (ILS) using a source with an unknown emission rate. As a result, laboratory proficiency can only be based on the mean and standard deviation of emission rates measured by the participating ILS laboratories. A reference material with a known emission rate has the potential to provide an independent assessment of laboratory performance as well as improve the quality of interlaboratory studies. Several international laboratories with different chamber testing systems demonstrated the ability to measure the emission rate of such a reference material within an acceptable measurement uncertainty. PMID:24843917

Howard-Reed, Cynthia; Liu, Zhe; Cox, Steven; Leber, Dennis; Samarov, Dan; Little, John C

2014-04-01

51

Indoor contaminants from newspapers: VOCs emissions in newspaper stands.  

PubMed

Mean volatile organic compound (VOC) concentrations in 16 newspaper stands and in two printing shops were monitored for the purpose of quantifying the various VOCs in these areas and to relate the results. In each site halogenated, oxygenated, aliphatic, and aromatic compounds were monitored during one workweek. They were sampled with diffusive samplers for thermal desorption and analysed by GC-MS. The results showed that in all newspaper stands the indoor levels of toluene were much higher than the outdoor levels; some sites had toluene indoor concentrations 100 times higher than their correspondent outdoor levels. The investigations in two printing shops confirmed that newspapers, in particular the inks, are the main sources of toluene in the newspaper stands. PMID:19108821

Caselli, Maurizio; de Gennaro, Gianluigi; Saracino, Maria Rosaria; Tutino, Maria

2009-02-01

52

[Study on the quantitative estimation method for VOCs emission from petrochemical storage tanks based on tanks 4.0.9d model].  

PubMed

VOCs emission from petrochemical storage tanks is one of the important emission sources in the petrochemical industry. In order to find out the VOCs emission amount of petrochemical storage tanks, Tanks 4.0.9d model is utilized to calculate the VOCs emission from different kinds of storage tanks. VOCs emissions from a horizontal tank, a vertical fixed roof tank, an internal floating roof tank and an external floating roof tank were calculated as an example. The consideration of the site meteorological information, the sealing information, the tank content information and unit conversion by using Tanks 4.0.9d model in China was also discussed. Tanks 4.0.9d model can be used to estimate VOCs emissions from petrochemical storage tanks in China as a simple and highly accurate method. PMID:24640914

Li, Jing; Wang, Min-Yan; Zhang, Jian; He, Wan-Qing; Nie, Lei; Shao, Xia

2013-12-01

53

Influence of tree provenance on biogenic VOC emissions of Scots pine (Pinus sylvestris) stumps  

NASA Astrophysics Data System (ADS)

Resin-storing plant species such as conifer trees can release substantial amounts of volatile organic compounds (VOCs) into the atmosphere under stress circumstances that cause resin flow. Wounding can be induced by animals, pathogens, wind or direct mechanical damage e.g. during harvesting. In atmospheric modelling of biogenic VOCs, actively growing vegetation has been mostly considered as the source of emissions. Root systems and stumps of resin-storing conifer trees could constitute a significant store of resin after tree cutting. Therefore, we assessed the VOC emission rates from the cut surface of Scots pine stumps and estimated the average emission rates for an area with a density of 2000 stumps per ha. The experiment was conducted with trees of one Estonian and three Finnish Scots pine provenances covering a 1200 km gradient at a common garden established in central Finland in 1991. VOC emissions were dominated by monoterpenes and less than 0.1% of the total emission was sesquiterpenes. ?-Pinene (7-92% of the total emissions) and 3-carene (0-76% of the total emissions) were the dominant monoterpenes. Proportions of ?-pinene and camphene were significantly lower and proportions of 3-carene, sabinene, ?-terpinene and terpinolene higher in the southernmost Saaremaa provenance compared to the other provenances. Total terpene emission rates (standardised to +20 °C) from stumps varied from 27 to 1582 mg h-1 m-2 when measured within 2-3 h after tree cutting. Emission rates decreased rapidly to between 2 and 79 mg h-1 m-2 at 50 days after cutting. The estimated daily terpene emission rates on a hectare basis from freshly cut stumps at a cut tree density of 2000 per ha varied depending on provenance. Estimated emission ranges were 100-710 g ha-1 d-1 and 137-970 g ha-1 d-1 in 40 and in 60 year-old forest stands, respectively. Our result suggests that emission directly from stump surfaces could be a significant source of monoterpene emissions for a few weeks after logging in a Scots pine stand, but provenance properties strongly affect resin flow from root to stump surface.

Kivimäenpää, Minna; Magsarjav, Narantsetseg; Ghimire, Rajendra; Markkanen, Juha-Matti; Heijari, Juha; Vuorinen, Martti; Holopainen, Jarmo K.

2012-12-01

54

Investigation Methods to Distinguish Between Vapor Intrusion and Indoor Sources of VOCS.  

National Technical Information Service (NTIS)

Indoor sources of volatile organic chemicals (VOCs) are ubiquitous, resulting in detectable concentrations in indoor air, often at concentrations above regulatory screening levels. At VOC contaminated sites with potential vapor intrusion concerns, the pre...

K. Gorder L. Beckley P. Philp T. Kuder T. McHugh

2010-01-01

55

Biogenic and Anthropogenic VOC Emissions over the Central and Southern U.S.: Results from Recent Airborne Field Campaigns (Invited)  

NASA Astrophysics Data System (ADS)

Over the last two years, the NCAR Trace Organic Gas Analyzer (TOGA), capable of quantifying over 50 individual gas-phase volatile organic compounds (VOCs), was deployed on two airborne field campaigns with flights over the central and southeast United States: Deep Convective Cloud and Chemistry (DC3), and Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks (NOMADSS). These studies provided opportunities to sample air masses dominated by individual emissions sources, including biomass burning, oil and gas extraction, biogenic activity, and marine emissions, as well as the impact of convection on recently emitted trace gases. Using observations of biogenic VOCs, including speciated monoterpenes, we will compare our findings with NCAR CESM CAM-chem model simulations using the MEGAN emissions inventory. Likewise, we will contrast our observations of anthropogenic VOCs over the continental U.S. to model simulations with anthropogenic inventories (e.g., NEI, EDGAR).

Hornbrook, R. S.; Apel, E. C.; Riemer, D. D.; Hills, A. J.; Kaser, L.; Emmons, L. K.; Lamarque, J.; Blake, N. J.; Simpson, I. J.; Blake, D. R.; Karl, T.; Yuan, B.

2013-12-01

56

Spatial/Temporal Variations and Source Apportionment of VOCs Monitored at Community Scale in an Urban Area  

PubMed Central

This study aimed to characterize spatial/temporal variations of ambient volatile organic compounds (VOCs) using a community-scale monitoring approach and identify the main sources of concern in Paterson, NJ, an urban area with mixed sources of VOCs. VOC samples were simultaneously collected from three local source-dominated (i.e., commercial, industrial, and mobile) sites in Paterson and one background site in Chester, NJ (located ?58 km southwest of Paterson). Samples were collected using the EPA TO-15 method from midnight to midnight, one in every sixth day over one year. Among the 60 analyzed VOCs, ten VOCs (acetylene, benzene, dichloromethane, ethylbenzene, methyl ethyl ketone, styrene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene) were selected to examine their spatial/temporal variations. All of the 10 VOCs in Paterson were significantly higher than the background site (p<0.01). Ethylbenzene, m,p-xylene, o-xylene, and p-dichlorobenzene measured at the commercial site were significantly higher than the industrial/mobile sites (p<0.01). Seven VOCs (acetylene, benzene, dichloromethane, methyl ethyl ketone, styrene, toluene, and p-dichlorobenzene) were significantly different by season (p<0.05), that is, higher in cold seasons than in warm seasons. In addition, dichloromethane, methyl ethyl ketone, and toluene were significantly higher on weekdays than weekend days (p<0.05). These results are consistent with literature data, indicating the impact of anthropogenic VOC sources on air pollution in Paterson. Positive Matrix Factorization (PMF) analysis was applied for 24-hour integrated VOC measurements in Paterson over one year and identified six contributing factors, including motor vehicle exhausts (20%), solvents uses (19%), industrial emissions (16%), mobile+stationery sources (12%), small shop emissions (11%), and others (22%). Additional locational analysis confirmed the identified sources were well matched with point sources located upwind in Paterson. The study demonstrated the community-scale monitoring approach can capture spatial variation of VOCs in an urban community with mixed VOC sources. It also provided robust data to identify major sources of concern in the community.

Yu, Chang Ho; Zhu, Xianlei; Fan, Zhi-hua

2014-01-01

57

The OECD-MAP emission inventory for SO 2, NO x and VOC in Western Europe  

NASA Astrophysics Data System (ADS)

This paper summarizes for 12 European OECD countries national emissions of SO 2, NO x, and VOC for man-made and natural sources, compiled by the OECD in its project on control of major air pollutants. The data are presented according to major emission source categories accounting for the various economic sectors and the different emission-generating processes within these. Data are also geographically disaggregated on a 50 × 50 km 2 basis. In order to verify emission data, they have been analysed with simple statistical methods; these analyses have helped to identify uncertainties in data, correcting the inventory, and thereby making it more comparable between countries. Differences in unit emissions for the same sectors in different countries can mostly be attributed to different existing industrial, energy and transportation patterns in different countries.

Lübkert, Barbara; de Tilly, Soizick

58

Characterization of low-VOC latex paints: Volatile organic compound content, VOC and aldehyde emissions, and paint performance. Final report, January 1997January 1999  

Microsoft Academic Search

The report gives results of laboratory tests to evaluate commercially available latex paints advertised as `low-odor,` `low-VOC (volatile organic compound),` or `no-VOC.` Measurements were performed to quantify the total content of VOCs in the paints and to identify the predominant VOCs and aldehydes in the emissions following application to test substrates. The performance of the paints was evaluated and compared

R. Fortmann; H. C. Lao; A. Ng; N. Roache

1999-01-01

59

Test methods for determining short and long term VOC emissions from latex paint  

SciTech Connect

The paper discusses an evaluation of latex paint (interior, water based) as a source of indoor pollution. A major objective of the research is the development of methods for predicting emissions of volatile organic compounds (VOCs) over time. Test specimens of painted gypsumboard are placed in dynamic flow-through test chambers. Samples of the outlet air are collected on Tenax sorbents and thermally desorbed for analysis by gas chromatography/flame ionization detection. These tests produce short- and long-term data for latex paint emissions of Texanol, 2-2(-butoxyethoxy)-ethanol, and glycols. Evaluation of the data shows that most of the Texanol emissions occur within the first few days, and emissions of the glycols occur over several months. This behavior may be described by an evaporative mass transfer process that dominates the short-term emissions, while long-term emissions are limited by diffusion processes within the dry paint-gypsumboard.

Krebs, K.; Lao, H.C.; Fortmann, R.; Tichenor, B.

1998-09-01

60

Fine-scale Source Distribution of Biogenic VOCs Measured by Proton-Transfer-Reaction Mass Spectrometry.  

NASA Astrophysics Data System (ADS)

We have recently deployed Proton-Transfer-Reaction Mass Spectrometry for measuring reactive biogenic trace gases at a loblolly pine plantation in North Carolina (Duke Forest) as well as a primary tropical rainforest in Costa Rica. An automated moveable inlet system allowed observations of the finescale source structure of various biogenics, such as isoprene, MVK+MAC, acetaldehyde, acetone, methanol and monoterpenes within the canopy using an inverse lagrangian dispersion model. The distribution of oxygenated compounds in general shows a complex behavior of emission and deposition. Together with eddy covariance measurements at the top of the canopy, which we compare with enclosure measurements, we are able to quantify finescale exchange processes of VOCs within the canopy. Our measurements demonstrate that the treatment of emission and deposition currently used for modeling oxygenated biogenic VOCs can only be seen as a first order approximation.

Karl, T.; Potosnak, M.; Guenther, A.; Nemitz, E.; Turnipseed, A.; Baker, B.; Geron, C.

2003-12-01

61

VOC emissions during outdoor ship painting and health-risk assessment  

Microsoft Academic Search

Painting of ship external surfaces in building or repair shipyards generates significant emissions of volatile organic compounds (VOC) to the atmosphere. Such emissions have not been specifically regulated so far. The purpose of our study is therefore to evaluate the quantities and as far as possible the nature of the emitted VOC, to characterize the dispersion of these chemicals in

Laure Malherbe; Corinne Mandin

2007-01-01

62

Evaluation of Potential VOC Screening Instruments.  

National Technical Information Service (NTIS)

The report describes the evaluation of potential fugitive source emission screening instruments for analysis of volatile organic compounds (VOCs). An initial review of available portable VOC detection instruments indicated that detectors operating on seve...

K. T. Menzies R. E. Fasano

1982-01-01

63

Industrial sector-based volatile organic compound (VOC) source profiles measured in manufacturing facilities in the Pearl River Delta, China.  

PubMed

Industrial sector-based VOC source profiles are reported for the Pearl River Delta (PRD) region, China, based source samples (stack emissions and fugitive emissions) analyzed from sources operating under normal conditions. The industrial sectors considered are printing (letterpress, offset and gravure printing processes), wood furniture coating, shoemaking, paint manufacturing and metal surface coating. More than 250 VOC species were detected following US EPA methods TO-14 and TO-15. The results indicated that benzene and toluene were the major species associated with letterpress printing, while ethyl acetate and isopropyl alcohol were the most abundant compounds of other two printing processes. Acetone and 2-butanone were the major species observed in the shoemaking sector. The source profile patterns were found to be similar for the paint manufacturing, wood furniture coating, and metal surface coating sectors, with aromatics being the most abundant group and oxygenated VOCs (OVOCs) as the second largest contributor in the profiles. While OVOCs were one of the most significant VOC groups detected in these five industrial sectors in the PRD region, they have not been reported in most other source profile studies. Such comparisons with other studies show that there are differences in source profiles for different regions or countries, indicating the importance of developing local source profiles. PMID:23584189

Zheng, Junyu; Yu, Yufan; Mo, Ziwei; Zhang, Zhou; Wang, Xinming; Yin, Shasha; Peng, Kang; Yang, Yang; Feng, Xiaoqiong; Cai, Huihua

2013-07-01

64

Analysis and comparison of trends in concentrations and emissions of VOC and CO and VOC:CO ratios in urban European cities  

NASA Astrophysics Data System (ADS)

Since 2007, more than half of the world's population live in urban areas. Megacities, urban agglomerations with more than 10 million inhabitants, are rapidly increasing in number: in 1950 there were only two, New York and Tokyo with ~12 million, while by 2005 there were already 20, with Tokyo ranging the 35 millions. The urban atmospheres of these megacities are dominated by pollutants associated with vehicular emissions, as well as the formation of secondary pollutants responsible for photochemical smog. A comparative assessment of emissions and concentrations of volatile organic compounds (VOC) and carbon monoxide (CO) ratios in London (L) and Paris (P) is hereby presented. The work is based on three recent studies by Baker et al. (2008), Parrish et al. (2009) and von Schneidemesser et al. (in press) where concentrations of these compounds were analyzed for 28 US cities in the former and some global megacities in the second and third studies. Considering the fact that VOC provide information on the main emissions sources of cities, these studies found that even though concentrations of VOC varied greatly among cities, the ratio with the combustion tracer CO remained rather constant and was very useful for city comparison, as well as a good indicator of traffic emissions. VOC patterns in ambient air concentrations were observed to be similar in most cities, being able to consider that deviations from those patterns could be the result of measurement problems. Nevertheless, the representation of these emissions in global inventories has large uncertainties. The goal of our study is to compare and contrast emission inventory estimates with measured ambient concentrations of non-methane hydrocarbons (NMHC) and CO, as well as NMHC:CO ratios. Within the European CityZen project we have built an updated global emissions inventory with the best available datasets of anthropogenic, biomass burning and natural sources. As part of this research we will follow the same approach to compare emissions ratios between NMHC and CO for the megacities region of Paris and London and to compare these trends with measured ambient concentrations from three monitoring sites: Eltham (L) suburban station, Marylebone Road (L) kerbside station and Les Halles (P) urban station for the period 1997-2006.

D'Angiola, A.; von Schneidemesser, E.; Granier, C.; Law, K.; Monks, P. S.

2010-12-01

65

Laboratory scale VOC emissions testing of air-dried basswood lumber  

Microsoft Academic Search

Random width, 32-mm (5\\/4-in) nominal thickness air- dried basswood lumber was received from a supplier in the Lake States region. Two laboratory-scale charges were cut from the lumber and kiln-dried to determine volatile organic compound (VOC) emissions as per federal guidelines. The mean emission value from the two charges was 0.0222 kg VOC as carbon per cubic meter (0.115 pounds

Rubin Shmulsky; Joseph Dahlen

66

Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants  

NASA Astrophysics Data System (ADS)

As volatile organic compounds (VOCs) significantly affect atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects), emission inventories defining regional and global biogenic VOC emission strengths are important. The aim of this work was to achieve a description of VOC emissions from poorly described tropical vegetation to be compared with the quite well investigated and highly heterogeneous emissions from Mediterranean vegetation. For this task, common plant species of both ecosystems were investigated. Sixteen plant species from the Mediterranean area, which is known for its special diversity in VOC emitting plant species, were chosen. In contrast, little information is currently available regarding emissions of VOCs from tropical tree species at the leaf level. Twelve plant species from different environments of the Amazon basin, i.e. Terra firme, Várzea and Igapó, were screened for emission of VOCs at leaf level with a branch enclosure system. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS) and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was quantitatively the most dominant compound emitted followed by monoterpenes, methanol and acetone. Most of the Mediterranean species emitted a variety of monoterpenes, whereas only five tropical species were monoterpene emitters exhibiting a quite conservative emission pattern (?-pinene > limonene > sabinene > ?-pinene). Mediterranean plants showed additional emissions of sesquiterpenes, whereas in the case of plants from the Amazon region no sesquiterpenes were detected probably due to a lack of sensitivity in the measuring systems. On the other hand methanol emissions, an indicator of growth, were common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed heterogeneous emissions including reactive VOC species which are not easily detected by flux measurements, give reason to perform more screening at leaf level and, whenever possible, within the forests under ambient conditions.

Bracho-Nunez, A.; Knothe, N. M.; Welter, S.; Staudt, M.; Costa, W. R.; Liberato, M. A. R.; Piedade, M. T. F.; Kesselmeier, J.

2012-11-01

67

VOC emissions during outdoor ship painting and health-risk assessment  

NASA Astrophysics Data System (ADS)

Painting of ship external surfaces in building or repair shipyards generates significant emissions of volatile organic compounds (VOC) to the atmosphere. Such emissions have not been specifically regulated so far. The purpose of our study is therefore to evaluate the quantities and as far as possible the nature of the emitted VOC, to characterize the dispersion of these chemicals in the atmosphere and to assess the exposure and resulting health risks for surrounding populations. This study is focused on VOC emitted during outdoor work involving use of paints and solvents. VOC emissions are diffuse, since they come from the whole painted surfaces. A methodology for quantifying them is developed and tested, using information provided by ALSTOM—Chantiers de l'Atlantique and data found in paint technical sheets. Its reliability is checked against emission values established by ALSTOM or found in literature. Then, for two particular situations, construction on one hand, repair on the other hand, atmospheric dispersion of total VOC is simulated to assess the long-term impact (characterized by the plume extension and the annual mean concentrations) of these compounds. Finally, a health-risk assessment based on the estimates is carried out to evaluate the risks by inhalation for people living near the site. Considering the presumed composition of paints and the available reference toxicological values, total VOC are entirely assimilated to toluene. In both examples (construction and repair) and in the current state of knowledge, the calculated risk is not of health concern. Several ways for taking this study further are proposed: a more exhaustive collection of data relative to VOC and other substances contained in paints, on-site measurement of VOC in the ambient air, characterization of diffuse emissions related to other activities, such as purging or welding, and other pollutants, like particles.

Malherbe, Laure; Mandin, Corinne

68

Vehicular emission of volatile organic compounds (VOCs) from a tunnel study in Hong Kong  

NASA Astrophysics Data System (ADS)

Vehicle emissions of VOCs were determined in summer and winter of 2003 at the Shing Mun Tunnel, Hong Kong. One hundred and ten VOCs were quantified in this study. The average concentration of the total measured VOCs at the inlet and outlet of the tunnel were 81 250 pptv and 117 850 pptv, respectively. Among the 110 compounds analyzed, ethene, ethyne and toluene were the most abundant species in the tunnel. The total measured VOC emission factors ranged from 67 mg veh-1 km-1 to 148 mg veh-1 km-1, with an average of 115 mg veh-1 km-1. The five most abundant VOCs observed in the tunnel were, in decreasing order, ethene, toluene, n-butane, propane and i-pentane. These five most abundant species contributed over 38% of the total measured VOCs emitted. The high propane and n-butane emissions were found to be associated with LPG-fueled taxi. And fair correlations were observed between marker species (ethene, i-pentane, n-nonane, BTEX) with fractions of gasoline-fueled or diesel-fueled vehicles. Moreover, ethene, ethyne, and propene are the key species that were abundant in the tunnel but not in gasoline vapors or LPG. In order to evaluate the ozone formation potential emissions in Hong Kong, the maximum increment reactivity is calculated. It was found that about 568 mg of O3 is induced by per vehicle per kilometer traveled. Among them, ethene, propene and toluene contribute most to the ozone-formation reactivity.

Ho, K. F.; Lee, S. C.; Ho, W. K.; Blake, D. R.; Cheng, Y.; Li, Y. S.; Fung, K.; Louie, P. K. K.; Park, D.

2009-06-01

69

SemiEmpirical Correlation to Estimate VOCs Emission Rates for Water-based Paints Used in Building Engineering  

Microsoft Academic Search

Volatile organic compounds (VOCs) emitted from surface coating have been caused growing public concern for air quality, even low-emitted VOCs from water-based paints for indoor air quality in Taiwan urban areas. On a view of point on engineering application, the paper proposes a mathematical model to simulate the VOCs dynamic emission based on mass transfer and molecular diffusion theories. A

Yu-Min Chang; Wei-Hsing Hu; Chih-Mei Chou; Wen-Bing Fang

70

Influence of the spatial resolution of satellite-derived vegetation parameters on the biogenic Volatile Organic Compounds (VOC) emission modeling  

NASA Astrophysics Data System (ADS)

Vegetation is a natural source of Volatile Organic Compounds (VOC) that plays an important role in atmospheric chemistry. The main objective of the current study is to implement a model to quantify process-based VOC emissions from plants that focuses on the relationship between the sensitivity of VOC emission estimates to spatial resolution data, based on scientific knowledge and vegetation dynamics derived from satellite observations. The Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) were elected to examine this issue using different resolutions of satellite-derived products: 22m from the DEIMOS-1 satellite, and 250m and 1000m provided by MODIS. The study is focused on an area of 80×80km2 in Portugal for 2011. Detailed land cover and meteorological data are also included in the emission quantification algorithm. The primary outcomes were determined using a multi-scale analysis showing spatial and temporal variations in the vegetation parameters and modeling results. The results confirm that the emissions model is highly sensitive to the spatial resolution of the satellite-derived data, resulting in about a 30% difference in total isoprene emissions for the study area.

Silveira, Carlos M. S.; Tchepel, Oxana A.

2014-03-01

71

Source Signature of Volatile Organic Compounds (VOCs) associated with oil and natural gas operations in Utah and Colorado  

NASA Astrophysics Data System (ADS)

The U.S. Energy Information Administration has reported a sharp increase in domestic oil and natural gas production from "unconventional" reserves (e.g., shale and tight sands) between 2005 and 2012. The recent growth in drilling and fossil fuel production has led to environmental concerns regarding local air quality. Severe wintertime ozone events (greater than 100 ppb ozone) have been observed in Utah's Uintah Basin and Wyoming's Upper Green River Basin, both of which contain large natural gas fields. Raw natural gas is a mixture of approximately 60-95 mole percent methane while the remaining fraction is composed of volatile organic compounds (VOCs) and other non-hydrocarbon gases. We measured an extensive set of VOCs and other trace gases near two highly active areas of oil and natural gas production in Utah's Uintah Basin and Colorado's Denver-Julesburg Basin in order to characterize primary emissions of VOCs associated with these industrial operations and identify the key VOCs that are precursors for potential ozone formation. UBWOS (Uintah Basin Winter Ozone Study) was conducted in Uintah County located in northeastern Utah in January-February 2012. Two Colorado studies were conducted at NOAA's Boulder Atmospheric Observatory in Weld County in northeastern Colorado in February-March 2011 and July-August 2012 as part of the NACHTT (Nitrogen, Aerosol Composition, and Halogens on a Tall Tower) and SONNE (Summer Ozone Near Natural gas Emissions) field experiments, respectively. The C2-C6 hydrocarbons were greatly enhanced for all of these studies. For example, the average propane mixing ratio observed during the Utah study was 58 ppb (median = 35 ppb, minimum = 0.8, maximum = 520 ppb propane) compared to urban averages which range between 0.3 and 6.0 ppb propane. We compare the ambient air composition from these studies to urban measurements in order to show that the VOC source signature from oil and natural gas operations is distinct and can be clearly distinguished from typical urban emissions associated with on-road combustion sources. We show that each geologic basin has a unique VOC source signature. We will examine the effects of photochemical processing of the primary VOC emissions by comparing the composition and OH reactivity for the wintertime studies to the summertime when there is active photochemistry occurring.

Gilman, J.; Lerner, B. M.; Warneke, C.; Holloway, J. S.; Peischl, J.; Ryerson, T. B.; Young, C. J.; Edwards, P.; Brown, S. S.; Wolfe, D. E.; Williams, E. J.; De Gouw, J. A.

2012-12-01

72

CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT  

EPA Science Inventory

The paper discusses the measurment and analysis of the patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board, using small environmental chamber tests. The formaldehyde emissions resulted in sharp increase of chamber air...

73

CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT: JOURNAL ARTICLE  

EPA Science Inventory

NRMRL-RTP-P- 474a Chang*, J.C.S., Guo*, Z., Fortmann, R.C., and Lao, H.-C. Characterization and Reduction of Formaldehyde Emissions from a Low-VOC Latex Paint. Indoor Air 12 (1):10-16 (2002). EPA/600/J-02/187. 01/10/2000 The patterns of formaldehyde emission from a low vol...

74

CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT  

EPA Science Inventory

The patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board were measured and analyzed by small environmental chamber tests. It was found that the formaldehyde emissions resulted in sharp increase of chamber air formaldehy...

75

Assessment of VOC emissions and their control from baker's yeast manufacturing facilities. Final report  

SciTech Connect

The Environmental Protection Agency's (EPA's) Control Technology Center (CTC) conducted a study to obtain information on the baker's yeast manufacturing industry. Baker's yeast is produced by a fermentation process that generates large quantities of ethanol and acetaldehyde. Currently, 13 facilities produce baker's yeast in the United States. The volatile organic compound (VOC) emission rate from a typical facility is estimated at 82 megagrams per year (90 tons per year). The majority of these emissions occurs in the final trade fermentations. The VOC emission alternatives that were evaluated during the study were process control measures to reduce the formation of VOC emissions as well as wet scrubbers, carbon adsorbers, incinerators, condensers, and biological filters to control VOC emissions. Of these approaches, it appears that process control measures, catalytic incinerators, or a combination of add-on control techniques (e.g., wet scrubbers followed by an incinerator or a biological filter) are the most feasible approaches for controlling yeast process emissions. Based on the results of the study, the control efficiency associated with the add-on control systems is estimated to be 95 to 98 percent. The report contains information on the baker's yeast fermentation process, the number and locations of yeast plants, the potential emissions from the process, and an evaluation of potential emission control options.

Barker, R.; Williamson, M.

1992-01-01

76

CHARACTERIZATION OF LOW-VOC LATEX PAINTS: VOLATILE ORGANIC COMPOUND CONTENT, VOC AND ALDEHYDE EMISSIONS, AND PAINT PERFORMANCE  

EPA Science Inventory

The report gives results of laboratory tests to evaluate commercially available latex paints advertised as "low-odor," "low-VOC (volatile organic compound)," or "no-VOC." Measurements were performed to quantify the total content of VOCs in the paints...

77

Contrasting responses of silver birch VOC emissions to short- and long-term herbivory.  

PubMed

There is a need to incorporate the effects of herbivore damage into future models of plant volatile organic compound (VOC) emissions at leaf or canopy levels. Short-term (a few seconds to 48 h) changes in shoot VOC emissions of silver birch (Betula pendula Roth) in response to feeding by geometrid moths (Erannis defoliaria Hübner) were monitored online by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS). In addition, two separate field experiments were established to study the effects of long-term foliage herbivory (FH, 30-32 days of feeding by geometrids Agriopis aurantiaria (Clerck) and E. defoliaria in two consecutive years) and bark herbivory (BH, 21 days of feeding by the pine weevil (Hylobius abietis L.) in the first year) on shoot and rhizosphere VOC emissions of three silver birch genotypes (gt14, gt15 and Hausjärvi provenance). Online monitoring of VOCs emitted from foliage damaged by geometrid larvae showed rapid bursts of green leaf volatiles (GLVs) immediately after feeding activity, whereas terpenoid emissions had a tendency to gradually increase during the monitoring period. Long-term FH caused transient increases in total monoterpene (MT) emissions from gt14 and sesquiterpene (SQT) emissions from Hausjärvi provenance, mainly in the last experimental season. In the BH experiment, genotype effects were detected, with gt14 trees having significantly higher total MT emissions compared with other genotypes. Only MTs were detected in the rhizosphere samples of both field experiments, but their emission rates were unaffected by genotype or herbivory. The results suggest that silver birch shows a rapid VOC emission response to short-term foliage herbivory, whereas the response to long-term foliage herbivory and bark herbivory is less pronounced and variable at different time points. PMID:24627262

Maja, Mengistu M; Kasurinen, Anne; Yli-Pirilä, Pasi; Joutsensaari, Jorma; Klemola, Tero; Holopainen, Toini; Holopainen, Jarmo K

2014-03-01

78

Control of VOC emissions from natural gas pipeline compressor station engines. Topical report, June 1990-January 1991  

SciTech Connect

The objective of the study was to develop information in support of the following areas: VOC control technology review for compressor station prime movers; Assessment of VOC/NOx control tradeoff for natural gas compressor stations. The major emphasis of the study was in the first area--VOC control technology review. In the second part of the study, Acurex was tasked to provide a general review of existing methods for evaluating VOC emissions control for ozone abatement and to recommend a method for VOC/NOx control tradeoff analysis.

Chu, E.K.

1991-01-01

79

Vehicular emission of volatile organic compounds (VOCs) from a tunnel study in Hong Kong  

NASA Astrophysics Data System (ADS)

Vehicle emissions of volatile organic compounds (VOCs) were determined at the Shing Mun Tunnel, Hong Kong in summer and winter of 2003. One hundred and ten VOCs were quantified in this study. The average concentration of the total measured VOCs at the inlet and outlet of the tunnel were 81 250 pptv and 117 850 pptv, respectively. Among the 110 compounds, ethene, ethyne and toluene were the most abundant species in the tunnel. The total measured VOC emission factors ranged from 67 mg veh-1 km-1 to 148 mg veh-1 km-1, with an average of 115 mg veh-1 km-1. The five most abundant VOCs observed in the tunnel were, in decreasing order, ethene, toluene, n-butane, propane and i-pentane. These five most abundant species contributed over 38% of the total measured VOCs emitted. The high propane and n-butane emissions were found to be associated with liquefied petroleum gas (LPG)-fueled taxis. Fair correlations were observed between marker species (ethene, i-pentane, n-nonane, and benzene, toluene, ethylbenzene and xylenes - BTEX) with fractions of gasoline-fueled or diesel-fueled vehicles. Moreover, ethene, ethyne, and propene are the key species that were abundant in the tunnel but not in gasoline vapors or LPG. The ozone formation potential from the VOCs in Hong Kong was evaluated by the maximum increment reactivity (MIR). It was found to be 568 mg of ozone per vehicle per kilometer traveled. Among them, ethene, propene and toluene contribute most to the ozone-formation reactivity.

Ho, K. F.; Lee, S. C.; Ho, W. K.; Blake, D. R.; Cheng, Y.; Li, Y. S.; Ho, S. S. H.; Fung, K.; Louie, P. K. K.; Park, D.

2009-10-01

80

A Global inventory of volatile organic compound emissions from anthropogenic sources  

NASA Astrophysics Data System (ADS)

As part of an effort to assess the potential impacts associated with global climate change, the U.S. Environmental Protection Agency's Office of Research and Development is supporting global atmospheric chemistry research by developing global scale estimates of volatile organic compound (VOC) emissions (excluding methane). Atmospheric chemistry models require, as one input, an emissions inventory of VOCs. Consequently, a global inventory of anthropogenic VOC emissions has been developed. The inventory includes VOC estimates for seven classes of VOCs: paraffins, olefins, aromatics (benzene, toluene, xylene), formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds. These classes represent general classes of VOC compounds which possess different chemical reactivities in the atmosphere. The technical approach used to develop this inventory involved four major steps. The first step was to identify the major anthropogenic sources of VOC emissions in the United States and to group these sources into 28 general source groups. Source groups were developed to represent general categories such as "sources associated with oil and natural gas production" and more specific categories such as savanna buming. Emission factors for these source groups were then developed using different techniques and data bases. For example, emission factors for oil and natural gas production were estimated by dividing the United States' emissions from oil and gas production operations by the amount of oil and natural gas produced in the United States. Multiplication of these emission factors by production/consumption statistics for other countries yielded global VOC emission estimates for specific source groups within those countries. The final step in development of the VOC inventory was to distribute emissions into 10° by 10° grid cells using detailed maps of population and industrial activity. The results of this study show total global anthropogenic VOC emissions of about 110,000 Gg/yr. This estimate is about 10% lower than global VOC inventories developed by other researchers. The study identifies the United States as the largest emitter (21% of the total global VOC), followed by the (former) USSR, China, India, and Japan. Globally, fuel wood combustion and savanna burning were among the largest VOC emission sources, accounting for over 35% of the total global VOC emissions. The production and use of gasoline, refuse disposal activities, and organic chemical and rubber manufacturing were also found to be significant sources of VOC emissions.

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

1992-06-01

81

Emissions of volatile organic compounds (VOCs) from the food and drink industries of the European community  

NASA Astrophysics Data System (ADS)

Estimates were made of the amounts of volatile organic compounds (VOCs) released into the atmosphere as a result of the industrial manufacture and processing of food and drink in the European Community. The estimates were based on a review of literature sources, industrial and government contacts and recent measurements. Data were found on seven food manufacturing sectors (baking, vegetable oil extraction, solid fat processing, animal rendering, fish meal processing, coffee production and sugar beet processing) and three drink manufacturing sectors (brewing, spirit production and wine making). The principle of a data quality label is advocated to illustrate the authors' confidence in the data, and to highlight areas for further research. Emissions of ethanol from bread baking and spirit maturation were found to be the principle sources. However, significant losses of hexane and large quantities of an ill-defined mixture of partially oxidized hydrocarbons were noted principally from seed oil extraction and the drying of plant material, respectively. This latter mixture included low molecular weight aldehydes, carboxylic acids, ketones, amines and esters. However, the precise composition of many emissions were found to be poorly understood. The total emission from the food and drink industry in the EC was calculated as 260 kt yr -1. However, many processes within the target industry were found to be completely uncharacterized and therefore not included in the overall estimate (e.g. soft drink manufacture, production of animal food, flavourings, vinegar, tea, crisps and other fried snacks). Moreover, the use of data quality labels illustrated the fact that many of our estimates were based on limited data. Hence, further emissions monitoring is recommended from identified sources (e.g. processing of sugar beet, solid fat and fish meal) and from uncharacterized sources.

Passant, Neil R.; Richardson, Stephen J.; Swannell, Richard P. J.; Gibson, N.; Woodfield, M. J.; van der Lugt, Jan Pieter; Wolsink, Johan H.; Hesselink, Paul G. M.

82

Composition and emissions of VOCs in main- and side-stream smoke of research cigarettes  

NASA Astrophysics Data System (ADS)

It is well known that mainstream (MS) and sidestream (SS) cigarette smoke contains a vast number of chemical substances. Previous studies have emphasized SS smoke rather than MS smoke to which smokers are exposed, and most have used chamber tests that have several disadvantages such as wall losses. Emissions from standard research cigarettes have been measured, but relatively few constituents have been reported, and only the 1R4F (low nicotine) cigarette type has been tested. This study provides a comprehensive characterization of total, MS and SS smoke emissions for the 1R5F (ultra low nicotine), 2R4F (low nicotine), and 1R3F (standard nicotine) research cigarettes research cigarettes, including emission factors for a number of toxic compounds (e.g., benzene) and tobacco smoke tracers (e.g., 2,5-dimethyl furan). Emissions of volatile organic compounds (VOCs) and particulate matter (PM) are quantified using a dynamic dilution emission measurement system that is shown to produce accurate, rapid and reproducible results for over 30 VOCs and PM. SS and MS emissions were accurately apportioned based on a mass balance of total emissions. As expected, SS emissions greatly exceeded MS emissions. The ultra low nicotine cigarette had lower emissions of most VOCs compared to low and standard nicotine cigarettes, which had similar emissions. Across the three types of cigarettes, emissions of benzene (296-535 ?g cig -1), toluene (541-1003 ?g cig -1), styrene (90-162 ?g cig -1), 2-dimethyl furan (71-244 ?g cig -1), naphthalene (15-18 ?g cig -1) and other VOCs were generally comparable to or somewhat higher than literature estimates using chamber tests.

Charles, Simone M.; Batterman, S. A.; Jia, Chunrong

83

Impact of air velocity, temperature, humidity, and air on long-term voc emissions from building products  

Microsoft Academic Search

The emissions of two volatile organic compounds (VOCs) of concern from five building products (BPs) were measured in the field and laboratory emission cell (FLEC) up to 250d. The BPs (VOCs selected on the basis of abundance and low human odor thresholds) were: nylon carpet with latex backing (2-ethylhexanol, 4-phenylcyclohexene), PVC flooring (2-ethylhexanol, phenol), floor varnish on pretreated beechwood parquet

Peder Wolkoff

1998-01-01

84

MODEL FOR EVALUATION OF REFINERY AND SYNFUELS VOC (VOLATILE ORGANIC COMPOUNDS) EMISSION DATA. VOLUME 1. TECHNICAL REPORT AND APPENDIX A  

EPA Science Inventory

The report describes the development of a model for estimating emissions of volatile organic compounds (VOCs) from petroleum refineries and synfuel plants. The model, responding to a need to define a consistent and comprehensive approach for estimating VOC emissions from these tw...

85

MODEL FOR EVALUATION OF REFINERY AND SYNFUELS VOC (VOLATILE ORGANIC COMPOUNDS) EMISSION DATA. VOLUME 2. APPENDICES B AND C  

EPA Science Inventory

The report describes the development of a model for estimating emissions of volatile organic compounds (VOCs) from petroleum refineries and synfuel plants. The model, responding to a need to define a consistent and comprehensive approach for estimating VOC emissions from these tw...

86

A framework and experimental study of an improved VOC/formaldehyde emission reference for environmental chamber tests  

NASA Astrophysics Data System (ADS)

Environmental chamber systems are usually employed in the testing of volatile organic compound (VOC) and formaldehyde emissions from building materials. The measurement accuracy of environmental chamber systems can be evaluated by VOC/formaldehyde emission references. However, the available VOC/formaldehyde emission references all have some limitations for applications to various scales of chambers. A framework for designing and using a target VOC/formaldehyde emission references to evaluate the performance of chamber systems for measuring VOC/formaldehyde emissions from building materials is studied. Liquid-inner tube diffusion-film-emission (LIFE) reference is improved in this study to meet the requirements of a target VOC/formaldehyde emission reference, such as reliability, similarity as building materials, efficiency for measurement. Equivalent emission characteristic parameters are designed for a toluene LIFE reference to perform similar to a building material. Chamber test of the LIFE reference is made in a 30 m3 stainless steel ventilated environmental chamber at 23 ± 1 °C and 50 ± 5% relative humidity. The experimental data match the predictions using LIFE emission model as well as building material emission model. The improvement of the LIFE reference enables its application for the evaluation of the performance of all kinds of environmental chambers as a general reference in tests of VOCs/formaldehyde emissions from building materials.

Wei, Wenjuan; Xiong, Jianyin; Zhao, Weiping; Zhang, Yinping

2014-01-01

87

Ozone reaction with clothing and its initiated VOC emissions in an environmental chamber.  

PubMed

Human health is adversely affected by ozone and the volatile organic compounds (VOCs) produced from its reactions in the indoor environment. Hence, it is important to characterize the ozone-initiated reactive chemistry under indoor conditions and study the influence of different factors on these reactions. This investigation studied the ozone reactions with clothing through a series of experiments conducted in an environmental chamber under various conditions. The study found that the ozone reactions with a soiled (human-worn) T-shirt consumed ozone and generated VOCs. The ozone removal rate and deposition velocity for the T-shirt increased with the increasing soiling level and air change rate, decreased at high ozone concentrations, and were relatively unaffected by the humidity. The deposition velocity for the soiled T-shirt ranged from 0.15 to 0.29 cm/s. The ozone-initiated VOC emissions included C6-C10 straight-chain saturated aldehydes, acetone, and 4-OPA (4-oxopentanal). The VOC emissions were generally higher at higher ozone, humidity, soiling of T-shirt, and air change rate. The total molar yield was approximately 0.5 in most cases, which means that for every two moles of ozone removed by the T-shirt surface, one mole of VOCs was produced. PMID:23841649

Rai, A C; Guo, B; Lin, C-H; Zhang, J; Pei, J; Chen, Q

2014-02-01

88

SURFACE-COATING-FREE MATERIALS AND REDUCTION OF VOC EMISSIONS FROM COATING OPERATIONS  

EPA Science Inventory

The paper discusses results of a July 1991 workshop, cosponsored by EPA and RTI, to explore the concept of surface-coating-free materials (SCFMs) and to discuss their use as a means of reducing volatile organic compound (VOC) and air toxic emissions from surface coating operation...

89

MODELED RESPONSE OF PHOTOCHEMICAL OXIDANTS TO SYSTEMATIC REDUCTIONS IN ANTHROPOGENIC VOC AND NOX EMISSIONS  

EPA Science Inventory

As an exercise in model sensitivity, the Environmental Protection Agency's Regional Oxidant Model (ROM) was run for several simulations to study the impact of across-the-board reductions in anthropogenic VOC and NOx emissions on the photochemical environment of the eastern United...

90

Vertically fired fume incinerator reduces VOC, HCl emissions while adapting to limited space  

Microsoft Academic Search

Merck's Flint River plant in Albany, GA had been concerned with the control of dimethylsulfide (DMS) and methyl chloride. In November 1980, the state of Georgia enacted air pollution regulations requiring a 90% (by weight) reduction of all volatile organic compound (VOC) emission. A complete vertical incineration system was selected that could easily be installed in the available area. Total

D. A. Olson; C. P. Wickersham

1985-01-01

91

Sensory and chemical characterization of VOC emissions from building products: impact of concentration and air velocity  

Microsoft Academic Search

The emissions from five commonly used building products were studied in small-scale test chambers over a period of 50 days. The odor intensity was assessed by a sensory panel and the concentrations of selected volatile organic compounds (VOCs) of concern for the indoor air quality were measured. The building products were three floor coverings: PVC, floor varnish on beechwood parquet

H. N. Knudsen; U. D. Kjaer; P. A. Nielsen; P. Wolkoff

1999-01-01

92

Eddy covariance VOC emission and deposition fluxes above grassland using PTR-TOF  

PubMed Central

Eddy covariance (EC) is the preferable technique for flux measurements since it is the only direct flux determination method. It requires a continuum of high time resolution measurements (e.g. 5-20 Hz). For volatile organic compounds (VOC) soft ionization via proton transfer reaction has proven to be a quantitative method for real time mass spectrometry; here we use a proton transfer reaction time of flight mass spectrometer (PTR-TOF) for 10 Hz EC measurements of full mass spectra up to m/z 315. The mass resolution of the PTR-TOF enabled the identification of chemical formulas and separation of oxygenated and hydrocarbon species exhibiting the same nominal mass. We determined 481 ion mass peaks from ambient air concentration above a managed, temperate mountain grassland in Neustift, Stubai Valley, Austria. During harvesting we found significant fluxes of 18 compounds distributed over 43 ions, including protonated parent compounds, as well as their isotopes and fragments and VOC-H+ – water clusters. The dominant BVOC fluxes were methanol, acetaldehyde, ethanol, hexenal and other C6 leaf wound compounds, acetone, acetic acid, monoterpenes and sequiterpenes. The smallest reliable fluxes we determined were less than 0.1 nmol m?2 s?1, as in the case of sesquiterpene emissions from freshly cut grass. Terpenoids, including mono- and sesquiterpenes, were also deposited to the grassland before and after the harvesting. During cutting, total VOC emission fluxes up to 200 nmolC m?2 s?1 were measured. Methanol emissions accounted for half of the emissions of oxygenated VOCs and a third of the carbon of all measured VOC emissions during harvesting.

Ruuskanen, T. M.; Muller, M.; Schnitzhofer, R.; Karl, T.; Graus, M.; Bamberger, I.; Hortnagl, L.; Brilli, F.; Wohlfahrt, G.; Hansel, A.

2013-01-01

93

Observational constraints on biogenic VOC emission model estimates (Invited)  

NASA Astrophysics Data System (ADS)

Chemistry and transport models require accurate estimates of biogenic volatile organic compound (BVOC) emissions in order to simulate the atmospheric constituents controlling air quality and climate, such as ozone and particles, and so the uncertainties associated with BVOC estimates may be limiting the development of effective air quality and climate management strategies. BVOC emission models include driving variables and algorithms that span scales from the leaf level to entire landscapes. While considerable effort has been made to improve BVOC emission models in the past decades, there have been relatively few attempts to quantify the uncertainties associated with these estimates or to rigorously assess emission modeling approaches. This presentation will summarize the availability of observations that can be used to constrain BVOC emission models including flux measurements (leaf enclosure, above canopy tower, and aircraft platforms) and ambient concentrations of BVOC and their products. Results from studies targeting specific BVOC emission processes (e.g., the response of isoprene emission to drought and the response of monoterpene emissions to bark beetle attack) will be shown and the application of these observations for BVOC model evaluation will be discussed. In addition, the results from multi-scale BVOC emission studies (leaf enclosure, whole canopy flux tower, regional aircraft eddy covariance) will be presented and a approach for incorporating these observations into a community model testbed will be described and used to evaluate regional BVOC emission models.

Guenther, A. B.

2013-12-01

94

Organic liquids storage tanks volatile organic compounds (VOCS) emissions dispersion and risk assessment in developing countries: the case of Dar-es-Salaam City, Tanzania.  

PubMed

The emission estimation of nine volatile organic compounds (VOCs) from eight organic liquids storage tanks companies in Dar-es-Salaam City Tanzania has been done by using US EPA standard regulatory storage tanks emission model (TANKS 4.9b). Total VOCs atmospheric emission has been established to be 853.20 metric tones/yr. It has been established further that petrol storage tanks contribute about 87% of total VOCs emitted, while tanks for other refined products and crude oil were emitting 10% and 3% of VOCs respectively. Of the eight sources (companies), the highest emission value from a single source was 233,222.94 kg/yr and the lowest single source emission value was 6881.87 kg/yr. The total VOCs emissions estimated for each of the eight sources were found to be higher than the standard level of 40,000 kg/yr per source for minor source according to US EPA except for two sources, which were emitting VOCs below the standard level. The annual emissions per single source for each of the VOCs were found to be below the US EPA emissions standard which is 2,000 kg/yr in all companies except the emission of hexane from company F1 which was slightly higher than the standard. The type of tanks used seems to significantly influence the emission rate. Vertical fixed roof tanks (VFRT) emit a lot more than externally floating roof tanks (EFRT) and internally floating roof tanks (IFRT). The use of IFRT and EFRT should be encouraged especially for storage of petrol which had highest atmospheric emission contribution. Model predicted atmospheric emissions are less than annual losses measured by companies in all the eight sources. It is possible that there are other routes for losses beside atmospheric emissions. It is therefore important that waste reduction efforts in these companies are directed not only to reducing atmospheric emissions, but also prevention of the spillage and leakage of stored liquid and curbing of the frequently reported illegal siphoning of stored products. Emission rates for benzene, toluene, and xylene were used as input to CALPUFF air dispersion model for the calculation of spatial downwind concentrations from area sources. By using global positioning system (GPS) and geographical information system (GIS) the spatial benzene concentration contributed by organic liquid storage tanks has been mapped for Dar-es-Salaam City. Highest concentrations for all the three toxic pollutants were observed at Kigamboni area, possibly because the area is located at the wind prevailing direction from the locations of the storage tanks. The model predicted concentrations downwind from the sources were below tolerable concentrations by WHO and US-OSHA. The highest 24 hrs averaging time benzene concentration was used for risk assessment in order to determine maximum carcinogenic risk amongst the population exposed at downwind. Established risk for adult and children at 2.9x10(-3) and 1.9x10(-3) respectively, are higher than the acceptable US-EPA risk of 1x10(-6). It is very likely that the actual VOCs concentrations in some urban areas in Tanzania including Dar-es-Salaam City are much higher than the levels reported in this study when other sources such as petrol stations and motor vehicles on the roads are considered. Tanzania Government therefore need to put in place: an air quality policy and legislation, establish air quality guidelines and acquire facilities which will enable the implementation of air quality monitoring and management programmes. PMID:16779602

Jackson, Msafiri M

2006-05-01

95

APPORTIONMENT OF RESIDENTIAL INDOOR VOCS AND ALDEHYDES TO INDOOR AND OUTDOOR SOURCES IN ROANOKE  

EPA Science Inventory

The average concentrations of a large number of VOC and aldehyde species measured in ten Roanoke, Virginia residences in wintertime have been apportioned according to their contributions from all inside sources and all outside sources. he two category apportionment was accomplish...

96

Stable carbon isotope ratio measurements of VOC over various source regions in Southern Germany aboard a Zeppelin  

NASA Astrophysics Data System (ADS)

On emission volatile organic compounds (VOC) contain a carbon isotope ratio specific to its origin. Chemical processing alters the isotope ratio in the atmosphere. In summer 2007 air samples were taken aboard a Zeppelin NT as part of the TRACKS campaign. The airship was equipped with a comprehensive set of sensing instruments to enable the characterization of the troposphere from 100 m to 1000 m above ground. VOC samples were analyzed offline by gas chromatography / isotope mass spectrometry. A sample volume of about 15 l of ambient air allowed the determination of isotopic carbon ratios with an accuracy of about ±1 at ambient mixing ratios. Isotope ratio data of different compounds were found to vary for different source regions and altitudes. Aromatic compounds showed ^13C values between -20 and -30 per mil. Methanol exhibited particularly low ^13C values over regions with pronounced biogenic emission, where ^13C values up to -44 per mil were measured. Comparing isotope data with online VOC measurements enables to evaluate the extent of air mass processing.

Wegener, R.; Holland, F.; Rohrer, F.; Wahner, A.; Krebsbach, M.; Knieling, P.; Heuser, H. P.; Spahn, H.; Koppmann, R.

2009-04-01

97

Volatile Organic Compound (VOC) Emissions from Dairy Cows and Their Waste  

NASA Astrophysics Data System (ADS)

Biogenic VOCs are typically defined as those directly emitted from plants, but approximately 6% of global net primary production is consumed by cattle that carry out enteric fermentation and then emit VOCs that could also be considered biogenic. Current regulatory estimates suggest that dairy cattle in central California emit VOCs at rates comparable to those from passenger vehicles in the region, and thus contribute significantly to the extreme non-attainment of ozone standards there. We report PTR-MS measurements of ammonia and VOCs, and cavity-enhanced-absorption gas analyzer (Los Gatos Research, Inc.) measurements of CH4, emitted from dairy cattle in various stages of pregnancy/lactation and their waste. Experiments were conducted in chambers at UC Davis that simulate freestall cow housing conditions. CH4 fluxes ranged from 125-374 lb/cow/year. The compounds with the highest fluxes from '3 cows+waste' treatments were: ammonia (1-18), methanol (0-2.3), acetone+propanal (0.2-0.7), dimethylsulfide (0-0.4), and mass 109 (likely ID = p-cresol; 0-0.3) in lb/cow/year. Mass 60 (likely ID = trimethylamine) and acetic acid were also abundant. There were 10s of additional compounds with detectable, but small, emissions. A few compounds that were likely emitted (i.e. ethanol, formaldehyde, and dimethylamine) were not quantified by the PTR-MS. The total flux for all measured organic gases (TOG = CH4 + PTR-MS VOCs(including acetone+propanal)) averaged 246±45 lb/cow/year for '3 cows+waste' treatments, and was dominated by methane (>98%). TOG flux for 'waste only' treatments averaged 1.1±0.1 lb/cow/year, and was instead dominated by VOC (>84%). The PTR-MS VOCs as a percent of TOG (0.6±0.2%) emitted from '3 cows+waste' treatments in chamber conditions was a factor of 10 smaller than that currently estimated by the California Air Resources Board. In addition, the ozone forming potentials of the most abundant VOCs are only about 10% those of typical combustion or plant-derived VOCs, implying dairy cattle have a smaller effect on ozone formation than currently assumed by air districts in central California.

Shaw, S.; Holzinger, R.; Mitloehner, F.; Goldstein, A.

2005-12-01

98

Needle removal by pine sawfly larvae increases branch-level VOC emissions and reduces below-ground emissions of Scots pine.  

PubMed

Climate warming is expected to increase the frequency of insect outbreaks in Boreal conifer forests. We evaluated how needle removal by the larvae of two diprionid sawfly species affects the composition and quantity of VOC emissions from Pinus sylvestris L. saplings. Feeding damage significantly increased the rate of localized VOC emissions from the damaged branch. The emissions of total monoterpenes (MTs) were dominating (96-98% of total VOCs) and increased by14-fold in Neodiprion sertifer-damaged branches and by 16-fold in Diprion pini-damaged branches compared to intact branches. Emissions of ?-3-carene, ?-pinene, sabinene, and ?-phellandrene were most responsive. Feeding damage by N. sertifer larvae increased the emission rates of total sesquiterpenes by 7-fold (4% of total VOCs) and total green leaf volatiles by 13-fold (<1% of total VOCs). The VOC emissions from N. sertifer larvae constituted nearly 25% of the total branch emissions. N. sertifer feeding in the lower branches induced 4-fold increase in MT emissions in the top crown. Defoliation of Scots pine by D. pini significantly reduced the below-ground emissions of total MTs by approximately 80%. We conclude that defoliators could significantly increase total VOC emissions from the Scots pine canopy including MT emissions from resin storing sawfly larvae. PMID:23586621

Ghimire, Rajendra P; Markkanen, Juha M; Kivimäenpää, Minna; Lyytikäinen-Saarenmaa, Päivi; Holopainen, Jarmo K

2013-05-01

99

Behavior of VOCs and Carbonyl Compounds Emission from Different Types of Wallpapers in Korea  

PubMed Central

Emissions of volatile organic compounds (VOCs) and carbonyls from three types of commercially available wallpapers (i.e., PVC-coated, paper-backed, natural material-coated) in Korea were evaluated using a 20 L small chamber. A total of 332 products were tested for emission factors, frequencies of occurrence and composition ratios. Toluene and formaldehyde concentrations were below Korean standard values for all products; however, the total VOC (TVOC) concentrations exceeded current standards (4.0 mg/m2·h) for 30 products. The TVOC emission factor for PVC-coated wallpapers, for which polymer materials are used in the manufacturing process, was seven and 16 times higher than those of paper-backed and natural material-coated wallpapers, respectively. The detection frequencies for toluene and formaldehyde were the highest (82.5%) and fourth highest (79.5%), respectively among the 50 target chemical species. The composition ratios for BTEX ranged from 0.3% to 5.1% and unidentified VOCs, which were not qualitatively analyzed using standard gas methods, ranged from 90.2% to 94.8%. Among six carbonyl compounds (acrolein was not detected in any type of wallpaper), acetone had the highest concentrations in PVC-coated (44.6%) and paper-backed (66.6%) wallpapers. Formaldehyde emissions were highest (64.6%) for natural material-coated wallpapers, a result of the formaldehyde-based resin used in the manufacturing process for these products.

Lim, Jungyun; Kim, Suejin; Kim, ARong; Lee, Wooseok; Han, Jinseok; Cha, Jun-Seok

2014-01-01

100

Behavior of VOCs and carbonyl compounds emission from different types of wallpapers in Korea.  

PubMed

Emissions of volatile organic compounds (VOCs) and carbonyls from three types of commercially available wallpapers (i.e., PVC-coated, paper-backed, natural material-coated) in Korea were evaluated using a 20 L small chamber. A total of 332 products were tested for emission factors, frequencies of occurrence and composition ratios. Toluene and formaldehyde concentrations were below Korean standard values for all products; however, the total VOC (TVOC) concentrations exceeded current standards (4.0 mg/m²·h) for 30 products. The TVOC emission factor for PVC-coated wallpapers, for which polymer materials are used in the manufacturing process, was seven and 16 times higher than those of paper-backed and natural material-coated wallpapers, respectively. The detection frequencies for toluene and formaldehyde were the highest (82.5%) and fourth highest (79.5%), respectively among the 50 target chemical species. The composition ratios for BTEX ranged from 0.3% to 5.1% and unidentified VOCs, which were not qualitatively analyzed using standard gas methods, ranged from 90.2% to 94.8%. Among six carbonyl compounds (acrolein was not detected in any type of wallpaper), acetone had the highest concentrations in PVC-coated (44.6%) and paper-backed (66.6%) wallpapers. Formaldehyde emissions were highest (64.6%) for natural material-coated wallpapers, a result of the formaldehyde-based resin used in the manufacturing process for these products. PMID:24747540

Lim, Jungyun; Kim, Suejin; Kim, Arong; Lee, Wooseok; Han, Jinseok; Cha, Jun-Seok

2014-04-01

101

Temperature and light dependence of the VOC emissions of Scots pine  

NASA Astrophysics Data System (ADS)

The volatile organic compound (VOC) emission rates of Scots pine (Pinus sylvestris L.) were measured from trees growing in a natural forest environment at two locations in Finland. The emission rate measurements were carried out using a dynamic flow through technique with samples collected on adsorbent tubes and analyzed using thermodesorption followed by a gas chromatograph with a mass-selective detector (GC-MS). The standard emission potentials (at 303.15 K and 1000 µmol photons m-2 s-1) were calculated for the measured compounds using nonlinear regression to fit the experimental data to temperature and light dependent emission algorithms. The observed total VOC emission rates varied between 21 and 874 ng/g(dw)*h and 268 and 1670 ng/g(dw)*h in southern and northern Finland, respectively. A clear seasonal cycle was detected with high emission rates in early spring, a decrease of the emissions in late spring and early summer, high emissions again in late summer, and a gradual decrease in autumn. The main emitted compounds were ?3-carene (southern Finland) and ?- and ?-pinene (northern Finland), with approximate relative contributions of 60-70% and 60-85% of the total observed monoterpene emission rates, respectively. Sesquiterpene (?-caryophyllene) and 2-methyl-3-buten-2-ol (MBO) emissions were initiated in early summer at both sites. The observed MBO emission rates were between 1 and 3.5% of the total monoterpene emission rates. The sesquiterpene emission rates varied between 2 and 5% of the total monoterpene emission rates in southern Finland, but were high (40%) in northern Finland in spring. Most of the measured emission rates were found to be well described by the temperature dependent emission algorithm. The calculated standard emission potentials were high in spring and early summer, decreased somewhat in late summer, and were high again towards autumn. The experimental coefficient ? ranged from 0.025 to 0.19 (average 0.10) in southern Finland, with strongest temperature dependence in spring and weakest in late summer. Only the emission rates of 1,8-cineole were found to be both light and temperature dependent. However, there were irregularities with the performance of the exponential temperature algorithm, and our results suggest that especially during the spring recovery period of the vegetation there may be several different processes contributing to the VOC emissions of Scots pine.

Tarvainen, V.; Hakola, H.; Hellén, H.; Bäck, J.; Hari, P.; Kulmala, M.

2004-10-01

102

Temperature and light dependence of the VOC emissions of Scots pine  

NASA Astrophysics Data System (ADS)

The volatile organic compound (VOC) emission rates of Scots pine (Pinus sylvestris L.) were measured from trees growing in a natural forest environment at two locations in Finland. The observed total VOC emission rates varied between 21 and 874 ngg-1 h-1 and 268 and 1670 ngg-1 h-1 in southern and northern Finland, respectively. A clear seasonal cycle was detected with high emission rates in early spring, a decrease of the emissions in late spring and early summer, high emissions again in late summer, and a gradual decrease in autumn.

The main emitted compounds were ?3-carene (southern Finland) and ?- and ?-pinene (northern Finland), with approximate relative contributions of 60-70% and 60-85% of the total observed monoterpene emission rates, respectively. Sesquiterpene (?-caryophyllene) and 2-methyl-3-buten-2-ol (MBO) emissions were initiated in early summer at both sites. The observed MBO emission rates were between 1 and 3.5% of the total monoterpene emission rates. The sesquiterpene emission rates varied between 2 and 5% of the total monoterpene emission rates in southern Finland, but were high (40%) in northern Finland in spring.

Most of the measured emission rates were found to be well described by the temperature dependent emission algorithm. The calculated standard emission potentials were high in spring and early summer, decreased somewhat in late summer, and were high again towards autumn. The experimental coefficient ? ranged from 0.025 to 0.19 (average 0.10) in southern Finland, with strongest temperature dependence in spring and weakest in late summer. Only the emission rates of 1,8-cineole were found to be both light and temperature dependent.

Tarvainen, V.; Hakola, H.; Hellén, H.; Bäck, J.; Hari, P.; Kulmala, M.

2005-03-01

103

Investigation of the emissions and profiles of a wide range of VOCs during the Clean air for London project  

NASA Astrophysics Data System (ADS)

The majority of the World's population live in polluted urbanized areas. Poor air quality is shortening life expectancy of people in the UK by an average 7-8 months and costs society around £20 billion per year.[1] Despite this, our understanding of atmospheric processing in urban environments and its effect on air quality is incomplete. Air quality models are used to predict how air quality changes given different concentrations of pollution precursors, such as volatile organic compounds (VOCs). The urban environment of megacities pose a unique challenge for air quality measurements and modelling, due to high population densities, pollution levels and complex infrastructure. For over 60 years the air quality in London has been monitored, however the existing measurements are limited to a small group of compounds. In order to fully understand the chemical and physical processes that occur in London, more intensive and comprehensive measurements should be made. The Clean air for London (ClearfLo) project was conducted to investigate the air quality, in particular the boundary layer pollution, of London. A relatively new technique, comprehensive two dimensional gas chromatography (GC×GC) [2] was combined with a well-established dual channel GC (DC-GC) [3] system to provide a more comprehensive measurement of VOCs. A total of 78 individual VOCs (36 aliphatics, 19 monoaromatics, 21 oxygenated and 2 halogenated) and 10 groups of VOCs (8 aliphatic, 1 monoaromatic and 1 monoterpene) from C1-C13+ were quantified. Seasonal and diurnal profiles of these VOCs have been found which show the influence of emission source and chemical processing. Including these extra VOCs should enhance the prediction capability of air quality models thus informing policy makers on how to potentially improve air quality in megacities. References 1. House of Commons Environmental Audit Committee, Air Quality: A follow-up report, Ninth Report of session 2012-12. 2. Lidster, R.T., J.F. Hamilton, and A.C. Lewis, The application of two total transfer valve modulators for comprehensive two-dimensional gas chromatography of volatile organic compounds. Journal of Separation Science, 2011. 34(7): p. 812-821. 3. Hopkins, J.R., C.E. Jones, and A.C. Lewis, A dual channel gas chromatograph for atmospheric analysis of volatile organic compounds including oxygenated and monoterpene compounds. Journal of Environmental Monitoring, 2011. 13(8): p. 2268-2276.

Holmes, Rachel; Lidster, Richard; Hamilton, Jacqueline; Lee, James; Hopkins, James; Whalley, Lisa; Lewis, Alistair

2014-05-01

104

Emissions and photochemistry of oxygenated VOCs in urban plumes in the Northeastern United States  

NASA Astrophysics Data System (ADS)

Photochemical processes inside urban plumes in the Northeast of the United States have been studied using a highly detailed chemical model, based upon the Master Chemical Mechanism (MCM). The model results have been compared to measurements of oxygenated VOCs (acetone, methyl ethyl ketone, acetaldehyde, acetic acid and methanol) obtained during several flights of the NOAA WP-3D aircraft, which sampled plumes from the New York City area during the ICARTT campaign in 2004. The agreement between the model and the measurements was within 40 60% for all species, except acetic acid. The model results have been used to study the formation and photochemical evolution of acetone, methyl ethyl ketone and acetaldehyde. Under the conditions encountered during the ICARTT campaign, acetone is produced from the oxidation of propane (24 28%) and i-propanol (<15%) and from a number of products of i-pentane oxidation. Methyl ethyl ketone (MEK) is mostly produced from the oxidation of n-butane (20 30%) and 3-methylpentane (<40%). Acetaldehyde is formed from several precursors, mostly small alkenes, >C5 alkanes, propanal and MEK. Ethane and ethanol oxidation account, respectively, for 6 23% and 5 25% of acetaldehyde photochemical formation. The results highlight the importance of long-chain alkanes for the photochemical production of ketones and the role of hydroperoxides in sustaining their formation far from the emission sources.

Sommariva, R.; de Gouw, J. A.; Trainer, M.; Atlas, E.; Goldan, P. D.; Kuster, W. C.; Warneke, C.; Fehsenfeld, F. C.

2008-06-01

105

Emissions and photochemistry of oxygenated VOCs in urban plumes in the Northeastern United States  

NASA Astrophysics Data System (ADS)

Photochemical processes inside urban plumes in the Northeast of the United States have been studied using a highly detailed chemical model, based upon the Master Chemical Mechanism (MCM). The model results have been compared to measurements of oxygenated VOCs (acetone, methyl ethyl ketone, acetaldehyde, acetic acid and methanol) obtained during several flights of the NOAA WP-3D aircraft, which sampled plumes from the New York City area during the ICARTT campaign in 2004. The agreement between the model and the measurements was within 40-60 % for all species, except acetic acid. The model results have been used to study the formation and photochemical evolution of acetone, methyl ethyl ketone and acetaldehyde. Under the conditions encountered during the ICARTT campaign, acetone is produced from the oxidation of propane (24-28 %) and i-propanol (<15 %) and from a number of products of i-pentane oxidation. Methyl ethyl ketone (MEK) is mostly produced from the oxidation of n-butane (20-30 %) and 3-methylpentane (<40 %). Acetaldehyde is formed from several precursors, mostly small alkenes, >C5 alkanes, propanal and MEK. Ethane and ethanol oxidation account, respectively, for 6-23 % and 5-25 % of acetaldehyde photochemical formation. The results highlight the importance of alkanes for the photochemical production of ketones and the role of hydroperoxides in sustaining their formation far from the emission sources.

Sommariva, R.; de Gouw, J. A.; Trainer, M.; Atlas, E.; Goldan, P. D.; Kuster, W. C.; Warneke, C.; Fehsenfeld, F. C.

2011-07-01

106

APPORTIONMENT OF RESIDENTIAL INDOOR AEROSOL, VOC, AND ALDEHYDE SPECIES TO INDOOR AND OUTDOOR SOURCES, AND THEIR SOURCE STRENGTHS  

EPA Science Inventory

The average concentrations of forty-five fine particle aerosol, VOC and aldehyde species measured in ten Boise ID residences in wintertime have been apportioned according to their contributions from all inside sources and all outside sources. he method depends on the availability...

107

Silent discharge plasma for point-of-use abatement of VOC emissions. Final report ESHCOO3(b)  

SciTech Connect

Los Alamos and SEMATECH have evaluated a silent discharge plasma (SDP) device for point-of-use (POU) control of specific semiconductor VOC emissions at the source. Destruction efficiencies were initially determined at the bench scale using controlled gas mixtures and system performance was measured for simulated emissions containing a variety of volatile organic compounds (including HMDS) and PFCs. Based on this work, a field-pilot unit was designed and tested at a SEMATECH member site using two slip-streams: (1) PGMEA and HMDS gas mixture from lithography tools and the, (2) acetone, PCE and methanol from a wet bench cleaning tool. Based on the pilot test data, CoO estimates for the SDP technology show annual operating expenses (including amortized capital and installation costs, maintenance, and utilities) are $8.3K for a single 250 scfm lithotrack tool. End-of-pipe (EOP) system costs are $33.3K per 1000 scfm as compared to about $22K per 1000 scfm for a typical EOP concentrator/thermal abatement system. LANL does not recommend replacing existing EOP systems with SDP. However SDP could be easily installed in {open_quotes}niche{close_quotes} circumstances for POU control of VOCs from lithotrack tools.

Coogan, J.J.; Jassal, A.

1997-02-14

108

Measurements of VOCs by proton transfer reaction mass spectrometry at a rural Ontario site: Sources and correlation to aerosol composition  

Microsoft Academic Search

Proton transfer reaction mass spectrometry (PTR-MS) volatile organic compound (VOC) measurements were made at the Centre for Atmospheric Research Experiments at Egbert, Ontario, over a five week period in May to June 2007. VOCs were also analyzed by gas chromatography and with a fluorescence detector sensitive to formaldehyde. This is a well positioned site for contrasting biogenic versus anthropogenic sources.

A. Vlasenko; J. G. Slowik; J. W. Bottenheim; P. C. Brickell; R. Y.-W. Chang; A. M. Macdonald; N. C. Shantz; S. J. Sjostedt; H. A. Wiebe; W. R. Leaitch; J. P. D. Abbatt

2009-01-01

109

Field emission electron source  

DOEpatents

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

Zettl, Alexander Karlwalter (Kensington, CA); Cohen, Marvin Lou (Berkeley, CA)

2000-01-01

110

VOC and particulate emissions from commercial cigarettes: analysis of 2,5-DMF as an ETS tracer.  

PubMed

Emissions of particulate matter (PM) and a broad suite of target volatile organic compounds (VOCs) in total, main-stream (MS) and side-stream (SS) smoke emissions are measured for six types of commercial cigarettes. The suitability of 2,5-dimethyl furan (DMF) as a tracer for environmental tobacco smoke (ETS) is investigated using laboratory results and a field study of 47 residences. Over 30 VOCs were characterized in cigarette smoke, including several that have not been reported previously. "regular tar", "low tar", menthol, and nonmenthol cigarettes showed only minor differences in PM and VOC emissions. When total emissions are considered, PM emissions averaged 18 +/- 2 mg cigarette(-1) and VOC emissions averaged 3644 +/- 160 mg cigarette(-1). DMF appears to satisfy all requirements for a tracer, namely, uniqueness, detectability, similar emission factors across tobacco products (211 +/- 16 microg cigarette(-1)), consistent proportions to other ETS compounds, and behavior similar to other ETS components in relevant environments. On the basis of field study results, DMF more reliably indicated smoking status than occupant-completed questionnaires, and cigarette smoking was responsible for significant fractions of benzene (50%), styrene (49%), and other VOCs in the smoker's homes. PMID:18351112

Charles, Simone M; Jia, Chunrong; Batterman, Stuart A; Godwin, Christopher

2008-02-15

111

Emissions of Biogenic Volatile Organic Compounds and Observations of VOC Oxidation at Harvard Forest  

NASA Astrophysics Data System (ADS)

The contribution of biogenic volatile organic compounds (BVOCs) to oxidant concentrations and secondary organic aerosol (SOA) production in forested environments depends on the emission rates of these compounds. Recent findings have suggested that the emission rates of BVOCs and the range of species emitted could be larger than previously thought. In this study, Proton Transfer Reaction Mass Spectrometry (PTR-MS) was used to obtain fast (<1 Hz) measurements of the predominant BVOC species, including isoprene, monoterpenes, and oxygenated BVOCs, above the canopy at Harvard Forest (Petersham, MA) during the summers of 2005, 2007, and 2008. Together with vertical wind data, these measurements are used to determine fluxes of BVOCs out of the forest using the virtual disjunct eddy covariance method. Concentrations of additional VOCs, including methyl vinyl ketone + methacrolein and terpene oxidation products were also measured. Isoprene is the dominant emitted species, with peak emission rates and midday mixing ratios of ca. 4 mg isoprene m-2 h-1 and ca. 5 ppbv, respectively. Isoprene emission rates are expected to vary with temperature and radiation (PAR) levels, and are compared to standard emission algorithms based on these parameters. Interannual variability in isoprene emission rates is also observed, and contributing factors are explored. In contrast to isoprene, maximum monoterpene concentrations typically were less than 1 ppbv and occurred in the early evening, with a local minimum at midday. Monoterpene fluxes are about an order of magnitude smaller than those of isoprene. The amplitude of the flux diurnal cycle suggests monoterpene emissions at Harvard Forest may exhibit light dependence as well as temperature dependence. Fluxes of oxygenated VOCs, including methanol, acetone, methyl ethyl ketone, and oxygenated terpenes that have rarely been observed previously, are also reported, and the dependence of their emission rates on factors such as time of year, temperature, radiation levels, and meteorological conditions are investigated.

McKinney, K. A.; Pho, T.; Vasta, A.; Lee, B. H.

2009-12-01

112

StreamVOC--A Deterministic Source-Apportionment Model to Estimate Volatile Organic Compound Concentrations in Rivers and Streams  

USGS Publications Warehouse

This report documents the construction and verification of the model, StreamVOC, that estimates (1) the time- and position-dependent concentrations of volatile organic compounds (VOCs) in rivers and streams as well as (2) the source apportionment (SA) of those concentrations. The model considers how different types of sources and loss processes can act together to yield a given observed VOC concentration. Reasons for interest in the relative and absolute contributions of different sources to contaminant concentrations include the need to apportion: (1) the origins for an observed contamination, and (2) the associated human and ecosystem risks. For VOCs, sources of interest include the atmosphere (by absorption), as well as point and nonpoint inflows of VOC-containing water. Loss processes of interest include volatilization to the atmosphere, degradation, and outflows of VOC-containing water from the stream to local ground water. This report presents the details of StreamVOC and compares model output with measured concentrations for eight VOCs found in the Aberjona River at Winchester, Massachusetts. Input data for the model were obtained during a synoptic study of the stream system conducted July 11-13, 2001, as part of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. The input data included a variety of basic stream characteristics (for example, flows, temperature, and VOC concentrations). The StreamVOC concentration results agreed moderately well with the measured concentration data for several VOCs and provided compound-dependent SA estimates as a function of longitudinal distance down the river. For many VOCs, the quality of the agreement between the model-simulated and measured concentrations could be improved by simple adjustments of the model input parameters. In general, this study illustrated: (1) the considerable difficulty of quantifying correctly the locations and magnitudes of ground-water-related sources of contamination in streams; and (2) that model-based estimates of stream VOC concentrations are likely to be most accurate when the major sources are point sources or tributaries where the spatial extent and magnitude of the sources are tightly constrained and easily determined.

Asher, William E.; Bender, David A.; Zogorski, John S.; Bartholomay, Roy C.

2006-01-01

113

Characterization of VOC Sources during the Texas Air Quality Study 2000 Using Proton-Transfer-Reaction Mass Spectrometry  

NASA Astrophysics Data System (ADS)

We used Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) for continuous real-time monitoring of volatile organic compounds (VOCs) at a site near the Houston Ship Channel during the Texas Air Quality Study 2000. Anthropogenic aromatics, alkenes, methanol, acetaldehyde, formaldehyde, acetone/propanal, a C7-Ketone, HCN and acrylonitrile were the most prominent compounds observed. Propene was the most abundant light-weight hydrocarbon detected by this technique, and was highly correlated with its oxidation products, formaldehyde and acetaldehyde, with typical propene-acetaldehyde ratios close to 1 in propene-dominated plumes. In the case of aromatic species the high time resolution of the obtained dataset helped in identifying different anthropogenic sources (e.g. industrial from urban emissions) and testing current emission inventories. In addition, a comparison with results from complimentary techniques (gas chromatography, differential optical absorption spectroscopy) was used to assess the selectivity of this on-line technique in a complex urban and industrial VOC matrix and give an interpretation of mass scans obtained by `soft' chemical ionization using proton-transfer via H3O+.

Karl, T.; Jobson, T.; William, K.; Williams, E.; Stutz, J.; Goldan, P.; Fall, R.; Fehsenfeld, F.; Lindinger, W.

2002-12-01

114

A Framework for Estimating Groundwater Concentrations of VOCs Emanating from a Vadose Zone Source (Invited)  

NASA Astrophysics Data System (ADS)

Soil vapor extraction (SVE) is a prevalent remediation approach for volatile organic compounds (VOCs) in the vadose zone. To support selection of an appropriate endpoint, i.e., the VOC concentration at which the remedy can be terminated for site closure or for transition to another remedy, an evaluation is needed to determine whether vadose zone contamination has been diminished sufficiently to protect groundwater. When vapor-phase diffusive transport is an important component of the overall contaminant fate and transport from a vadose zone source, a numerical analysis has shown that the expected groundwater concentration is controlled by a limited set of parameters, including site-specific dimensions, vadose zone properties, and source characteristics. Based on that approach, a framework was developed for estimating the VOC concentration in groundwater emanating from a vadose zone source. The framework uses results from three-dimensional VOC transport simulations for a matrix of parameter value combinations covering a range of potential site conditions. Interpolation and scaling processes are then applied to estimate contaminant concentrations at compliance (monitoring) wells for specific site conditions of interest. The framework has been incorporated into a user-friendly Microsoft Excel-based spreadsheet tool, which is made available to the public. The spreadsheet methodology provides a less computationally intensive alternative to three-dimensional multiphase modeling, while still allowing for parameter sensitivity and uncertainty analyses. In many cases, the framework spreadsheet may be appropriate to consider the effect of a diminishing vadose zone source over time. In this presentation, the conceptual model and spreadsheet development will be discussed.

Oostrom, M.; Truex, M.; Rice, A. K.; Carroll, K. C.; Simon, M. A.; Becker, D.

2013-12-01

115

COST EFFECTIVE VOC EMISSION CONTROL STARTEGIES FOR MILITARY, AEROSPACE,AND INDUSTRIAL PAINT SPRAY BOOTH OPERATIONS: COMBINING IMPROVED VENTILATION SYSTEMS WITH INNOVATIVE, LOW COST EMISSION CONTROL TECHNOLOGIES  

EPA Science Inventory

The paper describes a full-scale demonstration program in which several paint booths were modified for recirculation ventilation; the booth exhaust streams are vented to an innovative volatile organic compound (VOC) emission control system having extremely low operating costs. ...

116

Vertically fired fume incinerator reduces VOC, HCl emissions while adapting to limited space  

SciTech Connect

Merck's Flint River plant in Albany, GA had been concerned with the control of dimethylsulfide (DMS) and methyl chloride. In November 1980, the state of Georgia enacted air pollution regulations requiring a 90% (by weight) reduction of all volatile organic compound (VOC) emission. A complete vertical incineration system was selected that could easily be installed in the available area. Total space for the vertically fired incineration system is 510 sq ft, which is 64% less than for a comparable horizontally configured system. The 39 hp system has a heat input of 5.6MM Btu/hr. Since completion in March 1984, the incinerator system has proven to be reliable with good corrosion resistance. High control efficiency (99.99 + %) has given Merck an ultimate disposal method for converting VOCs to inert byproducts. Stack emissions (on a dry volume basis) are approximately: 150 ppm (maximum) NO/sub x/ as NO/sub 2/, less than 5 ppm HCl, less than 5 ppm chlorine, and 25 ppm (maximum) SO/sub 2/. Confirmation of these emissions levels is anticipated once the engineering staff can perform the necessary testing procedures.

Olson, D.A.; Wickersham, C.P.

1985-03-01

117

A MECHANISTIC MODEL FOR ESTIMATING VOC EMISSIONS FROM INDUSTRIAL PROCESS DRAINS PART I: THE UNDERLYING CHANNEL. (R823335)  

EPA Science Inventory

Recent research has indicated the potential for emissions of volatile organic compound (VOCs) from industrial process drains, and a need for better understanding of the mass transfer kinetics associated with such emissions. rn this study, a two-zone model was developed in a...

118

Seasonal and species-specific response of VOC emissions by Mediterranean woody plant to elevated ozone concentrations  

NASA Astrophysics Data System (ADS)

Although certain factors controlling plant emission rates of volatile organic compounds (VOCs) are reasonably well understood, the influence of elevated ozone concentrations as abiotic stress is mostly unknown. Therefore, we studied the effects of ozone concentrations on seasonal biogenic volatile organic compound (BVOC) emissions by different Mediterranean plant species in open top chambers (OTC). Three ozone treatments were established: filtered air (F), non-filtered air (NF), and fumigated air (NF+) adding 40 nl l -1 of ozone over NF. We studied the response of VOC emission in saplings of four Mediterranean woody plant species and subspecies: Ceratonia siliqua L., Olea europaea L., Quercus ilex spp. ilex L., and Quercus ilex spp. rotundifolia L. as representative of natural Mediterranean vegetation. No visible symptoms were detected on the leaves. No significant effect was found on net photosynthetic rates or stomatal conductance except for an increase in net photosynthetic rates in Quercus ilex ilex in spring and summer and an overall slight increase in Quercus ilex rotundifolia. Emissions of the total VOCs from Ceratonia siliqua in summer, and from Olea europaea and Quercus ilex rotundifolia in spring increased in ozone fumigated OTC in comparison with F or NF OTC. Decreased emissions were found in Quercus ilex rotundifolia in summer. There were no significant differences between ozone fumigation treatments for the other plant species and seasons. When considering particular VOCs, the results were also variable among species and time of the year. While ?-pinene emissions decreased with ozone fumigation in Olea europaea, ?-pinene and limonene emissions increased in Quercus ilex ilex. The responses of these particular VOCs did not always match the responses of total VOCs. In spite of this strong variability, when considering overall annual data for all species and seasons, there were increased net photosynthetic rates (37%) and limonene (95%) and total VOC (45%) emission rates in ozone-fumigated plants, whereas stomatal conductance did not change. Since VOCs are precursors of ozone, the increase in BVOC emission as a consequence of elevated tropospheric ozone concentrations may lead to positive feedback mechanisms in ozone formation.

Llusià, J.; Peñuelas, J.; Gimeno, B. S.

119

Nobel NOx and Voc Treatment Using Concentration and Plasma Decomposition  

Microsoft Academic Search

Stringent NOx and volatile organic compound (VOC) flue gas regulation was set force for various emission sources. The conventional emission control technologies such as SCR for NOx treatment and incineration and catalysts treatment for VOCs have limitations in terms of costs and performance. A novel economical and cost effective device is mandated to meet the regulation. A new approach consists

Toshiaki Yamamoto; Souma Asada; Tomohiro Iida; Yoshiyasu Ehara

2010-01-01

120

On-line field measurements of VOC emissions from a spruce tree at SMEAR Estonia  

NASA Astrophysics Data System (ADS)

We have investigated VOC emissions from a Norway spruce tree (Picea abies) in a hemi-boreal mixed forest in September and October 2012, using Proton Transfer Reaction Mass Spectrometry and Gas Chromatography - Mass Spectrometry techniques, applied in a dynamic branch enclosure system that was automatically operated with an electrical compressor. Parallel to BVOC measurements a vast amount of atmospheric (CO2, CH4, H2O, CO, particles) and meteorological (temperature, relative humidity, photosynthetic active radiation, wind speed and direction, precipitation) parameters were measured in the ambient atmosphere and inside the cuvette enclosure (temperature, relative humidity, O3). Prior to the measuring period, an innovatory experimental setup was built at Järvselja forest station, in order to accomplish the detection of BVOC and minimize sampling losses. Therefore, a new inlet line, consisting of 19.4m of heated and isolated glass tube was constructed. The new inlet system applied, allowed the on-line detection and calculation of sesquiterpene (SQT) emission rates for the first time in a hemi-boreal forest site. It total, 12 atmospheric relevant BVOCs were continuously monitored for a three week period and the emission rates were derived. Along with diurnal profiles and continuous timeless, some interesting observations showed the possibility of ozone effect on SQT emissions, the possibility of radiation effect on MT emissions, the higher induced emissions due to mechanical stress and the possibility for a valid intercomparison between different spruce trees located in mountain Kleiner Feldberg (Germany) and in Järvseja forest station (Estonia).

Bourtsoukidis, Efstratios; Bonn, Boris; Noe, Steffen

2013-04-01

121

[Volatile organic compounds (VOCs) emitted from wood furniture--estimation of emission rate by passive flux sampler].  

PubMed

The aim of this study was to evaluate aldehydes and other volatile organic compounds (VOCs) emission from furniture, which may cause hazardous influence on human being such as sick building/sick house syndrome. In this study, VOCs emitted from six kinds of wood furniture, including three set of dining tables and three beds, were analyzed by large chamber test method (JIS A 1911). Based on the emission rates of total VOCs (TVOC), the impacts on the indoor TVOC was estimated by the simulation model with volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table and one bed. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in two sets of dining tables and two beds. These results revealed that VOC emissions from wood furniture may influence significantly indoor air quality. Also, in this study, to establish the alternative method for large chamber test methods, emission rates from representative five areas of furniture unit were evaluated by passive sampling method using flux sampler and emission rate from full-sized furniture was predicted. Emission rates predicted by flux passive sampler were 10-106% (formaldehyde) and 8-141% (TVOC) of the data measured using large chamber test, respectively. PMID:22259847

Jinno, Hideto; Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Nishimura, Tetsuji

2011-01-01

122

Influence of Precision of Emission Characteristic Parameters on Model Prediction Error of VOCs/Formaldehyde from Dry Building Material  

PubMed Central

Mass transfer models are useful in predicting the emissions of volatile organic compounds (VOCs) and formaldehyde from building materials in indoor environments. They are also useful for human exposure evaluation and in sustainable building design. The measurement errors in the emission characteristic parameters in these mass transfer models, i.e., the initial emittable concentration (C0), the diffusion coefficient (D), and the partition coefficient (K), can result in errors in predicting indoor VOC and formaldehyde concentrations. These errors have not yet been quantitatively well analyzed in the literature. This paper addresses this by using modelling to assess these errors for some typical building conditions. The error in C0, as measured in environmental chambers and applied to a reference living room in Beijing, has the largest influence on the model prediction error in indoor VOC and formaldehyde concentration, while the error in K has the least effect. A correlation between the errors in D, K, and C0 and the error in the indoor VOC and formaldehyde concentration prediction is then derived for engineering applications. In addition, the influence of temperature on the model prediction of emissions is investigated. It shows the impact of temperature fluctuations on the prediction errors in indoor VOC and formaldehyde concentrations to be less than 7% at 23±0.5°C and less than 30% at 23±2°C.

Wei, Wenjuan; Xiong, Jianyin; Zhang, Yinping

2013-01-01

123

Influence of precision of emission characteristic parameters on model prediction error of VOCs/formaldehyde from dry building material.  

PubMed

Mass transfer models are useful in predicting the emissions of volatile organic compounds (VOCs) and formaldehyde from building materials in indoor environments. They are also useful for human exposure evaluation and in sustainable building design. The measurement errors in the emission characteristic parameters in these mass transfer models, i.e., the initial emittable concentration (C 0), the diffusion coefficient (D), and the partition coefficient (K), can result in errors in predicting indoor VOC and formaldehyde concentrations. These errors have not yet been quantitatively well analyzed in the literature. This paper addresses this by using modelling to assess these errors for some typical building conditions. The error in C 0, as measured in environmental chambers and applied to a reference living room in Beijing, has the largest influence on the model prediction error in indoor VOC and formaldehyde concentration, while the error in K has the least effect. A correlation between the errors in D, K, and C 0 and the error in the indoor VOC and formaldehyde concentration prediction is then derived for engineering applications. In addition, the influence of temperature on the model prediction of emissions is investigated. It shows the impact of temperature fluctuations on the prediction errors in indoor VOC and formaldehyde concentrations to be less than 7% at 23±0.5°C and less than 30% at 23±2°C. PMID:24312497

Wei, Wenjuan; Xiong, Jianyin; Zhang, Yinping

2013-01-01

124

Modeling the effects of VOC/NOx emissions on ozone synthesis in the cascadia airshed of the Pacific Northwest.  

PubMed

A modeling system consisting of MM5, Calmet, and Calgrid was used to investigate the sensitivity of anthropogenic volatile organic compound (VOC) and oxides of nitrogen (NOx) reductions on ozone formation within the Cascadia airshed of the Pacific Northwest. An ozone episode that occurred on July 11-14, 1996, was evaluated. During this event, high ozone levels were recorded at monitors downwind of Seattle, WA, and Portland, OR, with one monitor exceeding the 1 hr/120 ppb National Ambient Air Quality Standard (at 148 ppb), and six monitors above the proposed 8 hr/80 ppb standard (at 82-130 ppb). For this particular case, significant emissions reductions, between 25 and 75%, would be required to decrease peak ozone concentrations to desired levels. Reductions in VOC emissions alone, or a combination of reduced VOC and NOx emissions, were generally found to be most effective; reducing NOx emissions alone resulted in increased ozone in the Seattle area. When only VOC emissions were curtailed, ozone reductions occurred in the immediate vicinity of densely populated areas, while NOx reductions resulted in more widespread ozone reductions. PMID:15658221

Barna, M; Lamb, B; Westberg, H

2001-07-01

125

Characterization of VOCs Across Pennsylvania: Assessing Emissions from Rural, Forested, Agricultural and Natural Gas Drilling-Impacted Areas  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) of both biogenic and anthropogenic origin are important to troposphere chemistry, particularly the formation of photochemical smog and secondary organic aerosol. There is concern that increased natural gas exploration may lead to increased emissions of certain VOCs during well development and due to fugitive emissions from operational well sites and pipelines. For a six-day period in June 2012, a variety of VOCs were measured using canister sampling from a mobile measurement platform. Transects from southwestern to northeastern Pennsylvania were studied, with samples obtained in rural, forested, urban, farm-impacted and gas well-impacted sites. As expected, biogenic VOCs and isoprene oxidation products were enhanced in forested regions, while anthropogenic non-methane hydrocarbons were enhanced in urban areas. BTEX (benzene, toluene, ethylbenzene and xylenes) was enhanced in urban areas, but the concentrations of BTEX measured near developing and existing natural gas sites were similar to rural and forested sites. Halogenated hydrocarbons and Freon compounds were consistent at all site locations. We will discuss the specific concentrations and signatures of these compounds and assess the potential impact of agricultural activities and gas well development on the observed VOC concentrations and variability.

Grannas, A. M.; Fuentes, J. D.; Ramos-Garcés, F.; Wang, D. K.; Martins, D. K.

2012-12-01

126

Specification of Biogenic VOC Emission Data in the Coupled System of Regional Climate and Atmospheric Chemistry/Aerosols Model  

NASA Astrophysics Data System (ADS)

Coupling of regional climate model RegCM (Pal et al., 2007) and atmospheric chemistry/aerosols model CAMx (Environ, 2006) is being developed at our department under the CECILIA project (EC 6th FP) with the aim to study climate forcing due to atmospheric chemistry/aerosols on regional scale. Regional climate model RegCM with the resolution of 10 km drives transport, chemistry and dry/wet deposition of the CAMx model being operated on the Central and Eastern European domain and consequently the radiative active agents from the CAMx model enter the radiative transfer schemes for the calculation of heating rate changes in the regional climate model. In order to increase the accuracy of land cover data in this model system, a new input dataset has been prepared and used for the calculation of emissions of volatile organic compounds (VOCs) from natural sources. This dataset is mainly based on the single tree species database from the european project of JRC in Ispra - Agriculture, Forestry, and Other Land Uses in Europe (AFOLU) which covers most of the model domain. For the locations where AFOLU data were not available, i.e. basically non-EU areas, the USGS Eurasia land cover database has been used. Both databases are available in 1 km resolution. Emission factors for new land cover categories were obtained either from the laboratory measurements or from the literature. The Guenther et al. (1995) model algorithm has been used for the calculation of biogenic VOC (BVOC) emission fluxes. Effects of new land cover and BVOC emission data on the CAMx model simulations of low level ozone in the year 2000 have been studied. Improvement of model results when compared with the measured data may be seen, especially in the simulation of extreme values such as ozone summer maxima. References: - ENVIRON Corp., 2006. CAMx User’s Guide, version 4.40 - Guenther A., Hewitt N., Erickson D., Fall R., Geron Ch., Graedel T., Harley P., Klinger L., Lerdau M., McKay W. A., Pierce T., Scholes B., Steinbrecher R., Tallamraju R., Taylor J., Zimmerman P., 1995. Global model of natural organic compound emissions. J. Geophys. Res. 100, 8873-8892. - Pal, J. S., Giorgi, F., Bi, X., Elguindi, N., Solomon, F., Gao, X., Rauscher, S. A., Francisco, R., Zakey, A., Winter, J., Ashfaq, M., Syed, F. S., Bell, J. L., Diffenbaugh, N. S., Karmacharya, J., Konare, A., Martinez, D., da Rocha, R. P., Sloan, L. C., and Steiner, A. L., 2007. Regional climate modeling for the developing world: The ICTP RegCM3 and RegCNET, B. Am. Meteor. Soc., 88, 1395-1409.

Zemankova, K.; Huszar, P.

2009-12-01

127

On-Road Measurement of Vehichle VOC Emission Measurements During the 2003 Mexico City Metropolitan Area Field Campaign  

NASA Astrophysics Data System (ADS)

In the spring of 2003 (April 1-May 5), a multinational team of experts conducted an intensive, five-week field campaign in the Mexico City Metropolitan Area (MCMA). The overall goal of this effort was to contribute to the understanding of the air quality problem in megacities. As part of the campaign the Aerodyne Mobile Laboratory was equipped with state-of-the-art analytical instruments and deployed for measuring a variety of vehicle emissions in real time including CO2, NO2, NH3, HCHO, VOC's and volatile (at 600 °C) aerosol. The on-road measurement of vehicle VOC emissions were performed using a commercial version of the IONICON PTR-MS modified to operate onboard the mobile lab platform. A summary of the PTR-MS results from these and supporting laboratory experiments will be presented and discussed. In particular, selected chase events will be presented to illustrate the utility of the PTR-MS technique for characterizing vehicle VOC emission profiles in real time. VOC emission profiles for different vehicle engine types which include gasoline, diesel and compressed natural gas will be discussed and compared to the measurements from other high time response instruments deployed on the Aerodyne mobile van.

Knighton, W. B.; Rogers, T.; Grimsrud, E.; Herndon, S.; Allwine, E.; Lamb, B.; Velasco, E.; Westberg, H.

2004-12-01

128

LOW-VOC COATINGS FOR AUTOMOBILE REFINISHING USING NOVEL POLYMER RESINS  

EPA Science Inventory

Coating operations release a significant portion of the non-mobile source, volatile organic compounds (VOCs) into the air. The U.S. EPA's Emissions Characterization and Prevention Branch has formulated novel low-VOC coatings for the automotive refinishing sector that reduce VOC l...

129

Characterizing Emissions of Volatile Organic Compounds (VOCs) from Oil and Natural Gas Operations in Haynesville, Fayetteville, and Marcellus Shale Regions via Aircraft Observations During SENEX 2013  

NASA Astrophysics Data System (ADS)

The 2013 SENEX (Southeast Nexus) field campaign took place in June and July 2013 with to ascertain how the interaction of natural and anthropogenic emissions influence climate change and air quality throughout the southeastern United States. Five of the research flights utilizing the NOAA WP-3D aircraft focused on areas of intensive oil and natural gas production from various shale plays. These areas included the Haynesville shale in eastern Texas and western Louisiana, the Fayetteville shale in northern Arkansas, and the Marcellus shale in western Pennsylvania. According to the U.S. Energy Information Administration's (EIA) Annual Energy Outlook 2013 report, (1) the Haynesville, Fayetteville, and Marcellus shale collectively account for approximately 75% of the dry shale gas produced in the U.S., and (2) shale gas is expected to provide the largest source of growth in the U.S. natural gas supply over the next few decades. Depending on the particular shale formation, raw natural gas can contain significant amounts of non-methane hydrocarbons in the form of natural gas liquids (e.g., ethane, propane, butanes) and natural gas condensate (e.g., pentanes, cycloalkanes, and aromatics). Trace gases including methane, aromatics, formaldehyde, other oxygenated VOCs, carbon monoxide, and nitrogen oxides were measured by multiple instruments aboard the NOAA WP-3D research aircraft. Up to 72 whole air samples (WAS) were collected in flight and analyzed in the field post-flight for a variety of volatile organic compounds (VOCs). Whole air samples provide a detailed chemical snapshot that can be combined with higher time-resolved measurements in order to provide a more comprehensive chemical analysis. In this presentation, we will compare the emissions composition of the Haynesville, Fayetteville, and Marcellus shale plays to investigate the relative importance of primary VOC emissions on the formation of secondary pollutants such as ozone, oxygenated VOCs, and secondary organic aerosol.

Gilman, J.; Lerner, B. M.; Dumas, M.; Hughes, D.; Jaksich, A.; Hatch, C. D.; Graus, M.; Peischl, J.; Pollack, I. B.; Ryerson, T. B.; Holloway, J.; Trainer, M.; Aikin, K.; Kaiser, J.; Keutsch, F. N.; Wolfe, G. M.; Hanisco, T. F.; Warneke, C.; De Gouw, J. A.

2013-12-01

130

Methane Emissions from Industrial Sources.  

National Technical Information Service (NTIS)

This chapter identifies and describes major industrial sources of methane (CH4) emissions. For each source type examined, CH4 release points are identified and a detailed discussion of the factors affecting emissions is provided. A summary and discussion ...

L. L. Beck S. D. Piccot D. A. Kirchgessner

1993-01-01

131

SPATIAL AND SOURCE TYPE DISTRIBUTION OF EMISSIONS OF SELECTED TOXIC VOLATILE ORGANIC COMPOUNDS IN THE UNITED STATES IN 1990  

EPA Science Inventory

The annual anthropogenic emission, principal contributing source types, and spatial distributions for selected toxic volatile organic compounds (VOCS) are presented for the United States. oxic compounds addressed include acrylonitrile, benzene, perchloroethylene, and trichloroeth...

132

ATLAS OF SOURCE EMISSION PARTICLES  

EPA Science Inventory

An atlas of various source emission particles characterized by electron optical techniques has been compiled for use by air pollution investigators. The particles studied were emitted by mobile, stationary, and natural sources. Sources included automobiles, manufacturing operatio...

133

Organic Liquids Storage Tanks Volatile Organic Compounds (VOCS) Emissions Dispersion and Risk Assessment in Developing Countries: The Case of Dar-Es-Salaam City, Tanzania  

Microsoft Academic Search

The emission estimation of nine volatile organic compounds (VOCs) from eight organic liquids storage tanks companies in Dar-es-Salaam\\u000a City Tanzania has been done by using US EPA standard regulatory storage tanks emission model (TANKS 4.9b). Total VOCs atmospheric\\u000a emission has been established to be 853.20 metric tones\\/yr. It has been established further that petrol storage tanks contribute\\u000a about 87% of

Msafiri M. Jackson

2006-01-01

134

DEVELOPMENT OF THE 1980 NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSIONS INVENTORY: AREA SOURCES, PRODUCT D (VERSION 5.0)  

EPA Science Inventory

The 1980 NAPAP Emissions Inventory area source emissions data for the 48 contiguous United States are contained in the data file. Annual emissions of 11 pollutants (SO2, SO4, NOx, Pb, CO, HCl, HF, NH3, TSP, VOC, and total hydrocarbons) from 88 area source categories in 3,070 coun...

135

RESEARCH AREA -- MOBILE SOURCE OZONE PRECURSOR EMISSIONS CHARACTERIZATION AND MODELING (ATMOSPHERIC PROTECTION BRANCH - AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)  

EPA Science Inventory

The objective of this program is to characterize mobile source emissions which are one of the largest sources of tropospheric ozone precursor emissions (CO, NOx, and volatile organic compounds (VOCs) in the U.S. Due to the dynamic operation of motor vehicles, emissions are highl...

136

A rapid and accurate method, ventilated chamber C-history method, of measuring the emission characteristic parameters of formaldehyde/VOCs in building materials.  

PubMed

The indoor pollution caused by formaldehyde and volatile organic compounds (VOCs) emitted from building materials poses an adverse effect on people's health. It is necessary to understand and control the behaviors of the emission sources. Based on detailed mass transfer analysis on the emission process in a ventilated chamber, this paper proposes a novel method of measuring the three emission characteristic parameters, i.e., the initial emittable concentration, the diffusion coefficient and the partition coefficient. A linear correlation between the logarithm of dimensionless concentration and time is derived. The three parameters can then be calculated from the intercept and slope of the correlation. Compared with the closed chamber C-history method, the test is performed under ventilated condition thus some commonly-used measurement instruments (e.g., GC/MS, HPLC) can be applied. While compared with other methods, the present method can rapidly and accurately measure the three parameters, with experimental time less than 12h and R(2) ranging from 0.96 to 0.99 for the cases studied. Independent experiment was carried out to validate the developed method, and good agreement was observed between the simulations based on the determined parameters and experiments. The present method should prove useful for quick characterization of formaldehyde/VOC emissions from indoor materials. PMID:23994652

Huang, Shaodan; Xiong, Jianyin; Zhang, Yinping

2013-10-15

137

Characteristics of Secondary Emission Electron Gun and its Application to Decomposition of VOCs  

Microsoft Academic Search

Summary form only given. VOCs are released into the atmosphere from various plants and cars. And they are very harmful to human body. Nonthermal plasma methods using electrical discharges or electron beam irradiation are some of the emerging technologies for the disposal of VOCs, and other toxic substances. Especially, electron beam processing is more energy-and cost-efficient than others. We have

M. Shimizu; A. Fukamachi; M. Watanabe; A. Okino; E. Hotta

2007-01-01

138

Location and characterization of emission sources for airborne volatile organic compounds inside a refinery in Taiwan.  

PubMed

This study aimed to locate VOC emission sources and characterized their emitted VOCs. To avoid interferences from vehicle exhaust, all sampling sites were positioned inside the refinery. Samples, taken with canisters, were analyzed by GC-MS according to TO-14 method. The survey period extended from Febrary 2004 to December 2004, sampling twice per season. To interpret a large number of VOC data was a rather difficult task. This study featured using ordinary application software, Excel and Surfer, instead of expensive one like GIS, to overcome it. Consolidating data into a database on Excel facilitated retrieval, statistical analysis and presentation in the form of either table or graph. The cross analysis of the data suggested that the abundant VOCs were alkanes, alkenes, aromatics and cyclic HCs. Emission sources were located by mapping the concentration distribution of these four types of VOCs in terms of contour maps on Surfer. During eight surveys, five emission sources were located and their VOCs were characterized. PMID:16741796

Chen, Ching-Liang; Shu, Chi-Min; Fang, Hung-Yuan

2006-09-01

139

Volatile organic compounds (VOCs) measured at an urban site of Beijing: intercomparisons, emission ratios and factor analysis  

NASA Astrophysics Data System (ADS)

A proton transfer reaction mass spectrometer (PTR-MS) were used to measure volatile organic compounds (VOCs) in August - September, 2010 (summer) and December, 2010 - January, 2011 (winter) at an urban site on campus of Peking University. During the summer campaign, other instruments were also deployed at the site, including a custom-built GC-MS/FID, a GC-FID/PID, whole air samples (WAS) collected in canisters, and DNPH cartridges. VOCs concentrations measured by PTR-MS in the summer campaign compared well with the GC methods for most of the measured compounds. VOCs concentrations in winter strongly correlated with the combustion tracer CO for both hydrocarbons and oxygenates VOCs (OVOCs) and emission ratios to CO were calculated from linear fits of ambient concentrations. Emission ratios of aromatics in winter were significantly lower than those in summer, which may be due to: (1) higher CO emissions from coal burning for space heating in winter of Beijing; (2) higher industrial/solvent evaporations of aromatics in summer. The VOCs dataset with 19 species from PTR-MS and 56 species from GC-MS/FID was used for PMF analysis. A solution of five factors with no rotation (fPeak=0) was determined to be the best fit. Uncertainties of PMF analysis were explored by bootstrap method. The five factors included a fresh primary emissions factor (Factor 1, 27%), an aged primary emissions factor (Factor 2, 19%), a secondary & aged factor (Factor 3, 33%), a biogenic factor (Factor 4, 4%) and an industrial-like factor (Factor 5, 17%). The fresh and aged primary factor correlated well with NOx and CO, respectively. And the secondary & aged factor correlated well with PAN and Ox (O3+NO2). The contributions in different factors for various hydrocarbons are dependent on their reactivity. Comparing the obtained factor profiles shows that the aged primary emission factor and the secondary & aged factor are photochemically connected with the fresh primary emission factor. It suggested that PMF can provide information of photochemical processes in the atmosphere. The biogenic factor has a low MVK+MACR/isoprene ratio (0.506), indicating that it represents very fresh biogenic emissions and only transport no more than 0.5 hour in the urban environment.

Yuan, B.; Shao, M.; De Gouw, J. A.; Bon, D.; Wang, M.; Lu, S.; Zeng, L.; Zhang, Q.; Liu, Y.

2011-12-01

140

METHANE EMISSIONS FROM INDUSTRIAL SOURCES  

EPA Science Inventory

The chapter identifies and describes major industrial sources of methane (CH4) emissions. or each source type examined, it identifies CH4 release points and discusses in detail the factors affecting emissions. t also summarizes and discusses available global and country-specific ...

141

Investigating Sources and Emissions of Volatile Organic Compounds in California's San Joaquin Valley  

NASA Astrophysics Data System (ADS)

Emissions of Volatile Organic Compounds (VOCs) are regulated both as primary air pollutants and as precursors to the formation of secondary organic aerosol and tropospheric ozone. The San Joaquin Valley, a non-attainment area for ozone and PM2.5, contains a variety of point, area, and mobile VOC sources that contribute to both primary and secondary pollution. Using ambient measurements of over 100 different VOCs and Intermediate Volatility Organic Compounds (IVOCs) made at multiple field sites, we assess the magnitude and importance of various VOC sources in the San Joaquin Valley. Hourly measurements were made during the spring and summer of 2010 via in-situ gas chromatography in Bakersfield, CA as part of the CalNex experiment and also at a rural site located 100 km north of Bakersfield. Additionally, in-situ measurements of fresh motor vehicle exhaust were made in Oakland's Caldecott tunnel during the summer of 2010. Measurements include a broad array of anthropogenic and biogenic VOCs ranging in size from 1 to 17 carbon atoms, including many compounds with functional groups or substituents (e.g. aldehydes, ketones, alcohols, halogens, sulfur, & nitrogen). Using statistical methods of source apportionment, covariance, source receptor modeling, and air parcel back trajectories, we assess the impact of various sources on observed VOC concentrations at our field sites in the San Joaquin Valley. Prevalent sources include gasoline and diesel-vehicle exhaust, petroleum extraction/refining, biogenic emissions from agricultural crops and natural vegetation, and emissions from dairy operations and animal husbandry. We use measurements of fresh motor vehicle emissions from the Caldecott tunnel to constrain apportionment of gasoline and diesel-related VOCs and IVOCs in the San Joaquin Valley. Initial results from Bakersfield show substantial influence from local anthropogenic VOC sources, but there is evidence for transport of emissions from both anthropogenic and biogenic sources elsewhere in the region. For example, large biogenic sources appear to be regional rather than local since concentrations of isoprene peak in the late afternoon/evening suggesting transport from northern parts of the valley. We observed elevated concentrations of numerous alcohols and carbonyls in the San Joaquin Valley; for example mixing ratios of ethanol and acetone at the Bakersfield supersite had inner quartile ranges of 1.2-9.4 ppbv and 0.58-1.6 ppbv, with daytime averages near 2 and 1 ppbv, respectively. Additionally, we assess the sources and emissions of the IVOCs observed in the San Joaquin Valley, which include polycyclic aromatic hydrocarbons, large biogenic compounds, and high molecular weight alkanes and aromatics.

Gentner, D. R.; Harley, R. A.; Weber, R.; Karlik, J. F.; Goldstein, A. H.

2011-12-01

142

VOC Control: Current practices and future trends  

SciTech Connect

One of the most formidable challenges posed by the Clean Air Act Amendments of 1990 (CAAA) is the search for efficient and economical control strategies for volatile organic compounds (VOCs). VOCs are precursors to ground-level ozone, a major component in the formation of smog. Under the CAAA, thousands of currently unregulated sources will be required to reduce or eliminate VOC emissions. In addition, sources that are currently regulated may seek to evaluate alternative VOC control strategies to meet stricter regulatory requirements such as the maximum achievable control technology (MACT) requirements in Title III of the CAAA. Because of the increasing attention being given to VOC control, the American Institute of Chemical Engineers' (AIChE) Center for Waste Reduction Technologies (CWRT) initiated a study of VOC control technologies and regulatory initiatives. A key objective of the project was to identify and describe existing VOC control technologies and air regulations, as well as emerging technologies and forthcoming regulations. That work is the basis for this article.

Moretti, E.C.; Mukhopadhyay, N. (Baker Environment, Inc., Coraopolis, PA (United States))

1993-07-01

143

Assessment of neurobehavioral response in humans to low-level volatile organic compound (VOC) sources  

SciTech Connect

Occupants of sick buildings often complain of CNS symptoms including headache and memory loss, but little objective evidence of neurobehavioral effects exists. Available evidence of neurobehavioral effects of low level VOC exposure representative of new buildings is reviewed. Methods suitable for studying the neurobehavioral effects of low-level VOC exposure--including computerized behavioral tests, balance tests and sensory evoked potentials--are reviewed. The use of computerized behavioral tests in conjunction with symptom questionnaires is recommended for low-level VOC studies.

Otto, D.A.

1991-06-01

144

Development of a long-path Fourier transform infrared instrument for measurements of diffuse VOC emissions from the automobile industry  

NASA Astrophysics Data System (ADS)

This paper describes the construction of a long-path fourier transform instrument based on a BOMEM MB100 spectrometer, as well as the initial application for VOC monitoring at an automobile painting facility. The instrument gave detection limits of about 100 ug/m3 for a number of aromatic hydrocarbons along a 350 m folded measurement path (single end retroreflector setup, 180 scans, 1 cm-1 resolution). The instrument also yielded a detection limit of about 10 ug/m3 for butyl acetate which promotes this compound to be used as a tracer for VOC emissions originating from the automobile industry. The paper also includes a description of the spectral analysis applied involving single component classical least square fit and correction for water vapor interference.

Axelsson, Hakan; MacLaren, Scott; Galle, Bo; Mellqvist, Johan M.; Kloo, Henrik; Svedberg, Urban

1993-03-01

145

Macro-meso two-scale model for predicting the VOC diffusion coefficients and emission characteristics of porous building materials  

NASA Astrophysics Data System (ADS)

Through the observation of the pore structure and mercury intruding porosimetry (MIP) experiments of some typical porous building materials, we found that the diffusion coefficient of the material can be expressed by that of a representative elementary volume (REV) in which the pore structure can be simplified as a connection in series of macro and meso pores. Based upon that, a macro-meso two-scale model for predicting the diffusion coefficient of porous building materials is proposed. In contrast to the traditional porous mass transfer model for determining the diffusion coefficient described in the literature [Blondeau, P., Tiffonnet, A.L., Damian, A., Amiri, O., Molina, J.L., 2003. Assessment of contaminant diffusivities in building materials from porosimetry tests. Indoor Air 13, 302-310; Seo, J., Kato, S., Ataka, Y., Zhu, Q., 2005. Evaluation of effective diffusion coefficient in various building materials and absorbents by mercury intrusion porosimetry. In Proceedings of the Indoor Air, Beijing, China, pp. 1854-1859], the proposed model relates the volatile organic compound (VOC) diffusion coefficient of building material not only to the porosity of the building material, but also to the pore size distribution and pore connection modes. To verify the model, a series of experiments of VOC emissions of three types of medium-density board were conducted. The comparison of the model and experimental results shows that the proposed model agrees much better with the experimental results than the traditional models in the literature. More validation for other building materials is needed. The proposed model is useful for predicting the VOC diffusion coefficient of porous building materials and for developing low VOC emission building materials.

Xiong, Jianyin; Zhang, Yinping; Wang, Xinke; Chang, Dongwu

146

DEVELOPMENT OF THE 1980 NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSIONS INVENTORY: POINT SOURCES, PRODUCT B (VERSION 5.0)  

EPA Science Inventory

The 1980 NAPAP Emissions Inventory point source emissions data for the 48 contiguous United States are contained in the data file. Annual emissions of 11 pollutants (SO2, SO4, NOx, Pb, CO, HC1, HF, NH3, TSP, VOC, and total hydrocarbons) from 13,769 plants encompassing 34,483 emis...

147

Reduction of volatile organic compound emissions from the application of traffic markings. Final report  

Microsoft Academic Search

Traditional traffic marking materials (solvent-borne paints) are a source of volatile organic compound (VOC) emissions. The study was conducted to evaluate alternative traffic-marking techniques that can be used to reduce VOC emissions from this source. This document provides information on traffic marking application processes, VOC emissions and emission reductions, and costs associated with the alternative marking techniques. The primary conclusions

G. A. Aurand; M. B. Turner; C. J. Athey; R. M. Neulicht

1988-01-01

148

ASSESSMENT OF NEUROBEHAVIORAL RESPONSE IN HUMANS TO LOW-LEVEL VOLATILE ORGANIC COMPOUND (VOC) SOURCES  

EPA Science Inventory

Occupants of sick buildings often complain of CNS symptoms including headache and memory loss, but little objective evidence of neurobehavioral effects exists. vailable evidence of neurobehavioral effects of low level VOC exposure representative of new buildings is reviewed. etho...

149

Novel $\\\\hbox{NO}_{\\\\rm x}$ and VOC Treatment Using Concentration and Plasma Decomposition  

Microsoft Academic Search

Stringent NOx and volatile organic compound (VOC) flue gas regulation are set force for various industrial emission sources. The conventional emission control technologies such as selective catalytic reduction for NOx treatment and in- cineration and catalysts for VOC treatment have limitations in terms of operating conditions, costs, and performance. A novel, economical, and cost-effective device is mandated to meet the

Toshiaki Yamamoto; Soma Asada; Tomohiro Iida; Yoshiyasu Ehara

2011-01-01

150

Packaged thermal destruction system for VOC emissions. Phase 2. Final report, April 1991September 1993  

Microsoft Academic Search

Following successful proof of concept of an inward fired radiant burner for VOC fume incineration in Phase I, Phase II work was undertaken to commercialize the packaged abatement system. Laboratory evaluation of the burner demonstrated destruction removal efficiency (DRE) levels about 99.9% for most compounds tested, including chlorinated hydrocarbons. Fuel consumption was reduced by 30% with axial injection of the

D. F. Bartz; F. E. Moreno

1993-01-01

151

Flooding effects on plant physiology and VOC emissions from Amazonian tree species from two different flooding environments: Varzea and Igapo  

NASA Astrophysics Data System (ADS)

A land area of 300.000 km² in the Amazon basin is subjected to a continuous flooding pulse, being flooded for 210 days a-1 on an average (Junk et al. 1993). To survive the flooding period vegetation has developed several morphological, anatomical and physiological strategies to mitigate the produced stress due to root anoxia. One of the strategies is fermentation of sucrose in the roots to comply with the energy demand under anoxia. The resulting toxic metabolite ethanol is transported through the transpiration stream to the leaves and can be directly emitted into the atmosphere or converted to acetaldehyde and/or acetate, still volatile enough to be partly released. We investigated short-term and long-term flooding effects on physiology and VOC emission by plant species from várzea and igapó and observed ethanol and acetaldehyde emissions from the várzea species Vatairea guianensis after one day of flooding, which decreased considerably within the next three days. The same species from igapó showed no acetaldehyde emission and much lower emission rates of ethanol, than the várzea species. In contrast Hevea spruceana from both várzea and igapó showed no ethanol or acetaldehyde emissions. After long term flooding (2 months) we did not find any emissions of acetaldehyde or ethanol from all plant species investigated. However, isoprene and monoterpene emissions were clearly affected, showing a significant decrease. Carbon dioxide assimilation was not affected by short term flooding, but declined after two months root anoxia in the case of Hevea spruceana.

Bracho Nunez, A.; Knothe, N.; Liberato, M. A. R.; Schebeske, G.; Ciccioli, P.; Piedade, M. T. F.; Kesselmeier, J.

2009-04-01

152

Measurements of volatile organic compounds at a suburban ground site (T1) in Mexico City during the MILAGRO 2006 campaign: Measurement comparison, emission ratios, and source attribution  

SciTech Connect

Volatile organic compound (VOC) mixing ratios were measured with two different instruments at the T1 ground site in Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO) campaign in March of 2006. A gas chromatograph with flame ionization detector (GC-FID) quantified 18 light alkanes, alkenes and acetylene while a proton-transfer-reaction ion-trap mass spectrometer (PIT-MS) quantified 12 VOC species including oxygenated VOCs (OVOCs) and aromatics. A GC separation system was used in conjunction with the PIT-MS (GC-PIT-MS) to evaluate PIT-MS measurements and to aid in the identification of unknown VOCs. The VOC measurements are also compared to simultaneous canister samples and to two independent proton-transfer-reaction mass spectrometers (PTR-MS) deployed on a mobile and an airborne platform during MILAGRO. VOC diurnal cycles demonstrate the large influence of vehicle traffic and liquid propane gas (LPG) emissions during the night and photochemical processing during the afternoon. Emission ratios for VOCs and OVOCs relative to CO are derived from early-morning measurements. Average emission ratios for non-oxygenated species relative to CO are on average a factor of {approx}2 higher than measured for US cities. Emission ratios for OVOCs are estimated and compared to literature values the northeastern US and to tunnel studies in California. Positive matrix factorization analysis (PMF) is used to provide insight into VOC sources and processing. Three PMF factors were distinguished by the analysis including the emissions from vehicles, the use of liquid propane gas and the production of secondary VOCs + long-lived species. Emission ratios to CO calculated from the results of PMF analysis are compared to emission ratios calculated directly from measurements. The total PIT-MS signal is summed to estimate the fraction of identified versus unidentified VOC species.

Bon, D.M.; Springston, S.; M.Ulbrich, I.; de Gouw, J. A.; Warneke, C.; Kuster, W. C.; Alexander, M. L.; Baker, A.; Beyersdorf, A. J.; Blake, D.; Fall, R.; Jimenez, J. L., Herndon, S. C.; Huey, L. G.; Knighton, W. B.; Ortega, J.; Vargas, O.

2011-03-16

153

Response of ozone and nitrate to stationary source NO x emission reductions in the eastern USA  

Microsoft Academic Search

This study is an assessment of the impact of reduced stationary source NOx emissions on ground-level concentrations of ozone (O3) and dry-NO3 (HNO3(g) + NO3?(p)) in the eastern United States (EUS). Total anthropogenic NOx and VOC emissions have declined 32% and 20%, respectively, from 1997 to 2005 in the 20 eastern states participating in a NOx Budget Trading Program (NBP). Annual and

Thomas J. Butler; Francoise M. Vermeylen; Melissa Rury; Gene E. Likens; Brian Lee; George E. Bowker; Lance McCluney

2011-01-01

154

Source location and characterization of volatile organic compound emissions at a petrochemical plant in Kaohsiung, Taiwan.  

PubMed

This paper elucidated a novel approach to locating volatile organic compound (VOC) emission sources and characterizing their VOCs by database and contour plotting. The target of this survey was a petrochemical plant in Linyan, Kaohsiung County, Taiwan. Samples were taken with canisters from 25 sites inside this plant, twice per season, and analyzed by gas chromatography-mass spectrometry. The survey covered 1 whole year. By consolidated into a database, the data could be readily retrieved, statistically analyzed, and clearly presented in both table and graph forms. It followed from the cross-analysis of the database that the abundant types of VOCs were alkanes, alkenes/dienes, and aromatics, all of which accounted for 99% of total VOCs. By contour plotting, the emission sources for alkanes, aromatics, and alkenes/ dienes were successfully located. Through statistical analysis, the database could provide the range and 90% confidence interval of each species from each emission source. Both alkanes and alkene/dienes came from tank farm and naphtha cracking units and were mainly composed of C3-C5 members. Regarding aromatics, benzene, toluene, and xylenes were the primary species; they were emitted from tank farm, aromatic units, and xylene units. PMID:16295274

Chen, Chin-Liang; Fang, Hung Yuan; Shu, Chi-Min

2005-10-01

155

PAHs, carbonyls, VOCs and PM2.5 emission factors for pre-harvest burning of Florida sugarcane  

NASA Astrophysics Data System (ADS)

Emission factors (EFs) for hazardous polycyclic aromatic hydrocarbons (PAHs), carbonyls, and volatile organic compounds (VOCs) as well as other species such as PM2.5, elemental carbon (EC), organic carbon (OC), and tracer compounds (e.g., levoglucosan (LG) and other sugars) were investigated for sugarcane pre-harvest burning in Florida. A combustion chamber was used to simulate field burning conditions for determining EFs of both dry leaf and whole stalk biomass burning. Samples were collected from the chamber's exhaust duct following EPA sampling methods. The total PAH EFs were 7.13 ± 0.94 and 8.18 ± 3.26 mg kg-1 for dry leaf and whole sugarcane stalk burning, respectively. Carbonyl EFs were 201 ± 39 and 942 ± 539 mg kg-1 for dry leaf and whole stalk burning, respectively. PAH and carbonyl emissions were dominated by lower molecular weight compounds (e.g., naphthalene and formaldehyde, respectively). Of the aromatic VOCs studied, benzene was the predominant species. The PM2.5 EF was 2.49 ± 0.66 g kg-1, which is in range of the current published AP-42 EFs for particulate matter emissions from sugarcane burning and other sugarcane studies. The OC, EC and LG EFs were 0.16 ± 0.09 g kg-1, 0.71 ± 0.22 g kg-1, and 7.87 ± 5.42 mg kg-1, respectively. EFs of gaseous pollutants were generally lower than EFs from studies of agricultural residue combustion, likely due to the high combustion efficiency observed in this study.

Hall, Danielle; Wu, Chang-Yu; Hsu, Yu-Mei; Stormer, James; Engling, Guenter; Capeto, Krisha; Wang, Jun; Brown, Scott; Li, Hsing-Wang; Yu, Kuei-Min

2012-08-01

156

GLOBAL INVENTORY OF VOLATILE ORGANIC COMPOUND EMISSIONS FORM ANTHROPOGENIC SOURCES  

EPA Science Inventory

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

157

GLOBAL INVENTORY OF VOLATILE COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES  

EPA Science Inventory

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

158

Control of VOC emissions from natural gas pipeline compressor station engines. Topical report, June 1990January 1991  

Microsoft Academic Search

The objective of the study was to develop information in support of the following areas: VOC control technology review for compressor station prime movers; Assessment of VOC\\/NOx control tradeoff for natural gas compressor stations. The major emphasis of the study was in the first area--VOC control technology review. In the second part of the study, Acurex was tasked to provide

1991-01-01

159

The reduction of formaldehyde and VOCs emission from wood-based flooring by green adhesive using cashew nut shell liquid (CNSL).  

PubMed

To discuss the reduction of formaldehyde and volatile organic compound (VOC) emissions from engineered flooring, cashew nut shell liquid (CNSL)-formaldehyde (CF) resin and CF/PVAc resin were applied for the maple face of the veneer bonding on plywood. The CF resin was used to replace urea-formaldehyde (UF) resin in the formaldehyde-based resin system in order to reduce formaldehyde and VOC emissions from the adhesives used between the plywoods and fancy veneers. For the CF/PVAc resins, 5, 10, 20 or 30% of PVAc was added to the CF resin. The CF/PVAc resins showed better bonding than the commercial natural tannin adhesive with a higher level of wood penetration. The standard formaldehyde emission test and a VOC analyzer were used to determine the formaldehyde and VOC emissions, respectively, from the engineered floorings. The CF resin and CF/PVAc resin systems with UV coating satisfied the E(1) and E(0) grades of the Korean Standard. TVOC emission was slightly increased by the PVAc addition. PMID:20362392

Kim, Sumin

2010-10-15

160

VOC Destruction by Catalytic Combustion Microturbine  

SciTech Connect

This project concerned the application of a catalytic combustion system that has been married to a micro-turbine device. The catalytic combustion system decomposes the VOC's and transmits these gases to the gas turbine. The turbine has been altered to operate on very low-level BTU fuels equivalent to 1.5% methane in air. The performance of the micro-turbine for VOC elimination has some flexibility with respect to operating conditions, and the system is adaptable to multiple industrial applications. The VOC source that was been chosen for examination was the emissions from coal upgrading operations. The overall goal of the project was to examine the effectiveness of a catalytic combustion based system for elimination of VOCs while simultaneously producing electrical power for local consumption. Project specific objectives included assessment of the feasibility for using a Flex-Microturbine that generates power from natural gas while it consumes VOCs generated from site operations; development of an engineering plan for installation of the Flex-Microturbine system; operation of the micro-turbine through various changes in site and operation conditions; measurement of the VOC destruction quantitatively; and determination of the required improvements for further studies. The micro-turbine with the catalytic bed worked effectively to produce power on levels of fuel much lower than the original turbine design. The ability of the device to add or subtract supplemental fuel to augment the amount of VOC's in the inlet air flow made the device an effective replacement for a traditional flare. Concerns about particulates in the inlet flow and the presence of high sulfur concentrations with the VOC mixtures was identified as a drawback with the current catalytic design. A new microturbine design was developed based on this research that incorporates a thermal oxidizer in place of the catalytic bed for applications where particulates or contamination would limit the lifetime of the catalytic bed.

Tom Barton

2009-03-10

161

Evaluation of low-VOC latex paints  

Microsoft Academic Search

The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that the VOC contents of all four paints are considerably lower than those of conventional latex paints. Low-VOC emissions were confirmed by small

John C. S. Chang; Roy Fortmann; Nancy Roache; Huei-Chen Lao

1999-01-01

162

NOVEL CERAMIC-ORGANIC VAPOR PERMEATION MEMBRANES FOR VOC REMOVAL - PHASE I  

EPA Science Inventory

Vapor permeation holds much promise for becoming a highly efficient means of preventing VOC emissions that are now generated by a variety of stationary sources, including solvent and surface coating operations, gasoline storage operations, and printing operations. A limitation of...

163

NOVEL CERAMIC-ORGANIC VAPOR PERMEATION MEMBRANES FOR VOC REMOVAL - PHASE II  

EPA Science Inventory

Vapor permeation with highly permeable and organic-selective membranes is becoming an increasingly popular technique for preventing VOC emissions that are generated by a variety of stationary sources, including solvent and surface coating operations, gasoline storage operat...

164

Temporal variation of volatile organic compounds and their major emission sources in Seoul, Korea.  

PubMed

This study examines the characteristics of volatile organic compounds (VOCs) and their major emission sources at the Bulgwang site in Seoul, Korea. The annual levels of VOCs (96.2-121.1 ppb C) have shown a decreasing trend from 2004 to 2008. The most abundant component in Seoul was toluene, which accounted for over 23.5 % of the total VOCs on the parts per billion on a carbon basis, and the portions of alkanes with two to six carbons constituted the largest major lumped group, ranging from 40.1 to 48.4 % (45.3 ± 3.7 %) of the total VOCs. Major components of the solvent (toluene, m/p-xylene, o-xylene, and ethylbenzene) showed high in daytime and summer and low in nighttime and winter due mainly to the variation of the ambient temperature. The species mostly emitted from gasoline vapor (i/n-butane, i/n-pentane, n-hexane, and 2-methylpentane) and vehicular exhaust (ethylene, acetylene, and benzene) showed bimodal peaks in the diurnal variation around the commuting hours because of the high traffic volume. For the 14 out of 15 highest concentration species, the weekend effect was only evident on Sundays because of the stepwise implementation of the 5-day work-week system. Principal components analysis (PCA) was applied in order to identify the sources of the 15 highest concentration VOCs and, as a result, three principal components such as gasoline vapor (48.9 %), vehicular exhaust (17.9 %), and evaporation of solvents (9.8 %) were obtained to explain a total of 76.6 % of the data variance. Most influential contributing sources at the sampling site were traffic-related ones although the use of solvent was the dominant emission source based on the official emission inventory. PMID:23728967

Shin, H J; Roh, S A; Kim, J C; Lee, S J; Kim, Y P

2013-12-01

165

Characterization of Volatile Organic Compound (VOC) Emissions at Sites of Oil Sands Extraction and Upgrading in northern Alberta  

NASA Astrophysics Data System (ADS)

The crude oil reserves in Canada's oil sands are second only to Saudi Arabia, holding roughly 173 billion barrels of oil in the form of bitumen, an unconventional crude oil which does not flow and cannot be pumped without heating or dilution. Oil sands deposits are ultimately used to make the same petroleum products as conventional forms of crude oil, though more processing is required. Hydrocarbons are the basis of oil, coal and natural gas and are an important class of gases emitted into the atmosphere during oil production, particularly because of their effects on air quality and human health. However, they have only recently begun to be independently assessed in the oil sands regions. As part of the 2008 ARCTAS airborne mission, whole air samples were collected in the boundary layer above the surface mining operations of northern Alberta. Gas chromatography analysis revealed enhanced concentrations of 53 VOCs (C2 to C10) over the mining region. When compared to local background levels, the measured concentrations were enhanced up to 1.1-400 times for these compounds. To more fully characterize emissions, ground-based studies were conducted in summer 2010 and winter 2011 in the oil sands mining and upgrading areas. The data from the 200 ground-based samples revealed enhancements in the concentration of 65 VOCs. These compounds were elevated up to 1.1-3000 times above background concentrations and include C2-C8 alkanes, C1-C5 alkyl nitrates, C2-C4 alkenes and potentially toxic aromatic compounds such as benzene, toluene, and xylenes.

Marrero, J.; Simpson, I. J.; Meinardi, S.; Blake, D. R.

2011-12-01

166

Diffusion-controlled reference material for VOC emissions testing: effect of temperature and humidity.  

PubMed

A polymethylpentene film loaded with toluene is being developed as a reference material to support the reliable measurement of volatile organic compound emissions from building materials using environmental chambers. Earlier studies included the measurement of the material-phase diffusion coefficient (D) and material/air partition coefficient (K) at 23°C. A fundamental mass-transfer model can then be used to predict toluene emissions from the reference material at 23°C, serving as a reference for validating chamber-measured emission profiles. In this study, the effect of temperature and humidity on performance of the reference material was investigated. Reference material emissions were measured at 10, 23, and 30°C and at different relative humidity (RH) levels. D and K at different temperatures and RH were determined using an independent method. Results showed that RH does not significantly affect D and K and had no effect on emissions. However, emissions increased substantially at elevated temperatures due to the relationship between D and temperature. A statistical analysis shows good agreement between model-predicted and measured gas-phase concentrations, indicating that the model can accurately predict emission profiles as a function of temperature. The reference material can therefore be applied to a wide range of emission chamber testing conditions. PMID:24134062

Liu, Z; Howard-Reed, C; Cox, S S; Ye, W; Little, J C

2014-06-01

167

Emissions of VOCs at Urban Petrol Retail Distribution Centres in India (Delhi and Mumbai)  

Microsoft Academic Search

Air pollution has assumed gigantic proportion killing almost half a million Asians every year. Urban pollution mainly comprises of emissions from buses, trucks, motorcycle other forms of motorized transport and its supporting activities. As Asia's cities continue to expand the number of vehicles have risen resulting in greater pollution. Fugitive emissions from retail distribution center in urban area constitute a

Anjali Srivastava; A. E. Joseph; Ajit More; Sunil Patil

2005-01-01

168

Study of the VOC emissions from a municipal solid waste storage pilot-scale cell: Comparison with biogases from municipal waste landfill site  

SciTech Connect

Highlights: > Follow-up of the emission of VOCs in a municipal waste pilot-scale cell during the acidogenesis and acetogenesis phases. > Study from the very start of waste storage leading to a better understanding of the decomposition/degradation of waste. > Comparison of the results obtained on the pilot-scale cell with those from 3 biogases coming from the same landfill site. > A methodology of characterization for the progression of the stabilization/maturation of waste is finally proposed. - Abstract: The emission of volatile organic compounds (VOCs) from municipal solid waste stored in a pilot-scale cell containing 6.4 tonnes of waste (storage facility which is left open during the first period (40 days) and then closed with recirculation of leachates during a second period (100 days)) was followed by dynamic sampling on activated carbon and analysed by GC-MS after solvent extraction. This was done in order to know the VOC emissions before the installation of a methanogenesis process for the entire waste mass. The results, expressed in reference to toluene, were exploited during the whole study on all the analyzable VOCs: alcohols, ketones and esters, alkanes, benzenic and cyclic compounds, chlorinated compounds, terpene, and organic sulphides. The results of this study on the pilot-scale cell are then compared with those concerning three biogases from a municipal waste landfill: biogas (1) coming from waste cells being filled or recently closed, biogas (2) from all the waste storage cells on site, and biogas (3) which is a residual gas from old storage cells without aspiration of the gas. The analysis of the results obtained revealed: (i) a high emission of VOCs, principally alcohols, ketones and esters during the acidogenesis; (ii) a decrease in the alkane content and an increase in the terpene content were observed in the VOCs emitted during the production of methane; (iii) the production of heavier alkanes and an increase in the average number of carbon atoms per molecule of alkane with the progression of the stabilisation/maturation process were also observed. Previous studies have concentrated almost on the analysis of biogases from landfills. Our research aimed at gaining a more complete understanding of the decomposition/degradation of municipal solid waste by measuring the VOCs emitted from the very start of the landfill process i.e. during the acidogenesis and acetogenesis phases.

Chiriac, R., E-mail: rodica.chiriac@univ-lyon1.fr [Universite de Lyon, Universite Lyon 1, CNRS, UMR 5615, Laboratoire des Multimateriaux et Interfaces, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France); De Araujos Morais, J. [Universite Federal de Paraiba, Campus I Departamento de Engenharia Civil e Ambiental, Joao Pessoa, Paraiba (Brazil); Carre, J. [Universite de Lyon, Universite Lyon 1, CNRS, UMR 5256, Institut de Recherche sur la Catalyse et l'Environnement, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France); Bayard, R. [Universite de Lyon, INSA de Lyon, Laboratoire de Genie Civil et d'Ingenierie environnementale (LGCIE), F-69622 Villeurbanne (France); Chovelon, J.M. [Universite de Lyon, Universite Lyon 1, CNRS, UMR 5256, Institut de Recherche sur la Catalyse et l'Environnement, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France); Gourdon, R. [Universite de Lyon, INSA de Lyon, Laboratoire de Genie Civil et d'Ingenierie environnementale (LGCIE), F-69622 Villeurbanne (France)

2011-11-15

169

[Investigation on emission properties of biogenic VOCs of landscape plants in Shenzhen].  

PubMed

Isoprene and monoterpene emissions were characterized using flow and enclosure sampling method and GC-MS in USA for 158 species of plants growing in Shenzhen, China. This survey was designed to include all of the dominant plants within the Shenzhen region as well as unique plants such as Cycads. These are the first measurements in a subtropical Asian metropolis. Substantial isoprene emissions were observed from thirty-one species, including Caryota mitis, Adenanthera pavonina var. microsperma, Mangifera indica and Excoecoria agalloch. Monoterpene emissions were observed from fifty-two species, including Passiflora edulis, Bambusa glaucescens cv. silverstripe as well as some primitive and rare Cycadaceae and Cyatheaceae plants. For the first time some of red plants have been measured, most of them have the ability of releasing terpene. These results will be used to develop biogenic emission model estimates for Shenzhen and the surrounding region that can be used as inputs for regional air quality models. PMID:22468517

Huang, Ai-Kui; Li, Nan; Guenther, Alex; Greenberg, Jim; Baker, Brad; Graessli, Michael; Bai, Jian-Hui

2011-12-01

170

ANALYSIS OF SOCMI (SYNTHETIC ORGANIC CHEMICAL MANUFACTURING INDUSTRY) VOC (VOLATILE ORGANIC COMPOUND) FUGITIVE EMISSIONS DATA  

EPA Science Inventory

The report gives results of an examination of fugitive emission data from Synthetic Organic Chemical Manufacturing Industry (SOCMI) processing units (Collected under earlier EPA studies) for correlations between process variables and leak frequency. Although line temperature did ...

171

Global dataset of biogenic VOC emissions calculated by the MEGAN model over the last 30 years  

NASA Astrophysics Data System (ADS)

The Model of Emissions of Gases and Aerosols from Nature (MEGANv2.1) together with the Modern-Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields were used to create a global emission dataset of biogenic volatile organic compounds (BVOC) available on a monthly basis for the time period of 1980-2010. This dataset is called MEGAN-MACC. The model estimated mean annual total BVOC emission of 760 Tg (C) yr-1 consisting of isoprene (70%), monoterpenes (11%), methanol (6%), acetone (3%), sesquiterpenes (2.5%) and other BVOC species each contributing less than 2%. Several sensitivity model runs were performed to study the impact of different model input and model settings on isoprene estimates and resulted in differences of up to ±17% of the reference isoprene total. A greater impact was observed for a sensitivity run applying parameterization of soil moisture deficit that led to a 50% reduction of isoprene emissions on a global scale, most significantly in specific regions of Africa, South America and Australia. MEGAN-MACC estimates are comparable to results of previous studies. More detailed comparison with other isoprene inventories indicated significant spatial and temporal differences between the datasets especially for Australia, Southeast Asia and South America. MEGAN-MACC estimates of isoprene, ?-pinene and group of monoterpenes showed a reasonable agreement with surface flux measurements at sites located in tropical forests in the Amazon and Malaysia. The model was able to capture the seasonal variation of isoprene emissions in the Amazon forest.

Sindelarova, K.; Granier, C.; Bouarar, I.; Guenther, A.; Tilmes, S.; Stavrakou, T.; Müller, J.-F.; Kuhn, U.; Stefani, P.; Knorr, W.

2014-04-01

172

Source Analysis of Volatile Organic Compounds by Positive Matrix Factorization in Urban and Rural Environments in Beijing  

Microsoft Academic Search

This study applies advance receptor model positive matrix factorization (PMF) source analysis to one-hour resolution VOC data collected at Yufa (rural site) and Peking University, or PKU (urban site), in Beijing. A range of major VOC sources was identified, including vehicle emissions, LPG, coal combustion and biogenic emissions. Vehicle activities contributed approximately 62% of VOC loading and 55% of ozone

Zibing Yuan; Alexis Kai Hon Lau; Min Shao; Peter K. K. Louie; Shaw Chen Liu; Tong Zhu

2009-01-01

173

Source analysis of volatile organic compounds by positive matrix factorization in urban and rural environments in Beijing  

Microsoft Academic Search

This paper applies advance receptor model positive matrix factorization (PMF) source analysis to 1-h resolution VOC data collected at Yufa (rural site) and Peking University, or PKU (urban site), in Beijing. A range of major VOC sources was identified, including vehicle emissions, liquefied petroleum gas, coal combustion, and biogenic emissions. Vehicle activities contributed approximately 62% of VOC loading and 55%

Zibing Yuan; Alexis Kai Hon Lau; Min Shao; Peter K. K. Louie; Shaw Chen Liu; Tong Zhu

2009-01-01

174

Development of a Chemical Speciation Database and Software for Processing VOC Emissions for Air Quality Models  

Microsoft Academic Search

The chemical categories used in volatile organic compound speciation profiles in current emissions databases are inconsistent, include many categories that are not actual compounds, and assignments to these categories to different chemical mechanisms are inconsistent and difficult to update as new mechanisms or profiles are developed. To address this, we developed a chemical speciation database that includes assignments of actual

William P. L. Carter

175

PARAMETERS IMPACTING THE EMISSIONS OF SELECTED VOCS FROM THE TONER FOR A SPECIFIC PHOTOCOPIER  

EPA Science Inventory

The paper gives results of the measurement of emissions--using a laboratory thermal desorption apparatus--from a number of nominally identical photocopier toners (manufactured for use in a specific model copier) when the toners were heated to fuser temperature (180-200?C). The o...

176

Parameters Impacting the Emissions of Selected VOCs from the Toner for a Specific Photocopier.  

National Technical Information Service (NTIS)

The paper gives results of the measurement of emission--using a laboratory thermal desorption apparatus--from a number of nominally identical photocopier toners (manufactured for use in a specific model copier) when the toners were heated to fuser tempera...

D. B. Henschel R. C. Fortmann N. F. Roache X. Liu

2000-01-01

177

DEVELOPMENT OF TRANSITION METAL OXIDE-ZEOLITE CATALYSTS TO CONTROL CHLORINATED VOC AIR EMISSIONS  

EPA Science Inventory

The paper discusses the development of transition metal oxide (TMO)-zeolite oxidation catalysts to control chlorinated volatile organic compound (CVOC) air emissions. esearch has been initiated to enhance the utility of these catalysts by the development of a sorption-catalyst sy...

178

Identification of atmospheric volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds in Hong Kong  

Microsoft Academic Search

Volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds are the major organic pollutants in the atmosphere. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan area of Hong Kong. A 12-month monitoring program for VOCs, PAHs and carbonyl compounds was performed at a roadside urban station at Hong Kong Polytechnic University

K. F. Ho; S. C. Lee

2002-01-01

179

Source-Receptor Study of Volatile Organic Compounds and Particulate Matter in the Kanawha Valley, WV. 2. Analysis of Factors Contributing to VOC and Particle Exposures.  

National Technical Information Service (NTIS)

The Kanawha Valley region of West Virginia includes a deep river valley with a large population living in close proximity to many potential sources of ambient volatile organics compounds (VOCs). The Valley runs approximately 100 km from Alloy to Nitro and...

M. A. Cohen P. B. Ryan J. D. Spengler H. Oezkaynak C. Hayes

1991-01-01

180

Using thermodesorption-GC\\/cryocondensation-FT-IR for the measurement of biogenic VOC emissions  

Microsoft Academic Search

For the investigation of terpene emissions from plants a thermodesorption-GC\\/cryocondensation-FT-IR system was used to complement\\u000a GC\\/MS measurements. FT-IR spectra allow to obtain structural information on functional groups, especially if they contain\\u000a oxygen. Measurements of the release of volatile organic compounds from pine trees (Pinus sylvestris L.) and lavender show the potential of GC\\/FT-IR to detect and quantify terpenes down to

J. Geiger; T. Hoffmann; J. Kahl; D. Klockow; E. H. Korte; W. Schrader

1998-01-01

181

Study of the VOC emissions from a municipal solid waste storage pilot-scale cell: Comparison with biogases from municipal waste landfill site  

Microsoft Academic Search

The emission of volatile organic compounds (VOCs) from municipal solid waste stored in a pilot-scale cell containing 6.4tonnes of waste (storage facility which is left open during the first period (40days) and then closed with recirculation of leachates during a second period (100days)) was followed by dynamic sampling on activated carbon and analysed by GC–MS after solvent extraction. This was

R. Chiriac; J. De Araujos Morais; J. Carre; R. Bayard; J. M. Chovelon; R. Gourdon

2011-01-01

182

A corona discharge atmospheric pressure chemical ionization source with selective NO(+) formation and its application for monoaromatic VOC detection.  

PubMed

We have developed a new type of corona discharge (CD) for atmospheric pressure chemical ionization (APCI) for application in ion mobility spectrometry (IMS) as well as in mass spectrometry (MS). While the other CD-APCI sources are able to generate H3O(+)·(H2O)n as the major reactant ions in N2 or in zero air, the present CD-APCI source has the ability to generate up to 84% NO(+)·(H2O)n reactant ions in zero air. The change of the working gas from zero air to N2 allows us to change the major reactant ions from NO(+)·(H2O)n to H3O(+)·(H2O)n. In this paper we present the description of the new CD-APCI and discuss the processes associated with the NO(+) formation. The selective formation of NO(+)·(H2O)n reactant ions offers chemical ionization based on these ions which can be of great advantage for some classes of chemicals. We demonstrate here a significant increase in the sensitivity of the IMS-MS instrument for monoaromatic volatile organic compound (VOC) detection upon NO(+)·(H2O)n chemical ionization. PMID:24081306

Sabo, Martin; Matej?ík, Štefan

2013-11-21

183

Relative contribution of oxygenated hydrocarbons to the total biogenic VOC emissions of selected mid-European agricultural and natural plant species  

NASA Astrophysics Data System (ADS)

Emission rates of more than 50 individual VOCs were determined for eight plant species and three different types of grass land typical for natural deciduous and agricultural vegetation in Austria. In addition to the emissions of isoprene and monoterpenes, 33 biogenic oxygenated volatile organic compounds (BOVOCs) were detected. Of these, 2-methyl-l-propanol, 1-butanal, 2-butanal, 1-pentanol, 3-pentanol, 1-hexanol, 6-methyl-5-hepten-2-one, butanal and ethylhexylacetate were observed for the first time as plant emissions. In terms of prevalence of one of the groups of emitted VOCs (isoprene, terpenes, BOVOCs) the grain plants wheat and rye, grape, oilseed rape and the decidous trees hombeam and birch could be classified as "BOVOC"-emitters. For the grass plots examined, BOVOCs and terpenes appear to be of equal importance. The emission rates of the total assigned organic plant emissions ranged from 0.01 ? g -1 h -1 for wheat to 0.8 ?g g -1 h -1 for oak (based on dry leaf weight). Intercomparison with available data from other studies show that our emission rates are rather at the lower end of reported ranges. The influence of the stage of growth was examined for rye, rape (comparing emissions of blossoming and nonblossoming plants) and for grape (with and without fruit). Emission rate differences for different stages of growth varied from nondetectable for blossoming and nonblossoming rye to a factor of six for the grape with fruits vs grape without fruits (emission rate based on dry leaf weight). The major decidous tree in Austria (beech) is a terpene emitter, with the contribution of BOVOCs below 5% of the total assigned emissions of 0.2 ?g g -1 h -1 for the investigations of 20°C.

König, Georg; Brunda, Monika; Puxbaum, Hans; Hewitt, C. Nicholas; Duckham, S. Craig; Rudolph, Jochen

184

Use of Compound-Specific Stable Isotope Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs.  

National Technical Information Service (NTIS)

The objective of the present study is an empirical validation of selected adsorbents for preconcentration of TCE, PCE and benzene in air samples containing low concentrations of these VOCs. For validation of adsorbent tube performance, we sought to: 1) us...

M. Klisch R. P. Philp T. Kuder T. McHugh

2012-01-01

185

Use of Compound Specific Stable Isotope Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs.  

National Technical Information Service (NTIS)

The objective of the present study is an empirical validation of selected adsorbents for preconcentration of TCE, PCE and benzene in air samples containing low concentrations of these VOCs. For validation of adsorbent tube performance, we sought to: 1) us...

M. Klisch R. P. Philp T. Kuder T. McHugh

2012-01-01

186

Extended emission around GPS radio sources  

Microsoft Academic Search

Extended radio emission detected around a sample of GHz Peaked Spectrum (GPS) radio sources is discussed. Evidence for extended emission which is related to the GPS source is found in 6 objects out of 33. Three objects are associated with quasars with core-jet pc-scale morphology, and three are identified with galaxies with symmetric (CSO) radio morphology. We conclude that the

C. Stanghellini; C. P. O'Dea; D. Dallacasa; P. Cassaro; S. A. Baum; R. Fanti; C. Fanti

2005-01-01

187

Effect of Wind Tunnel Air Velocity on VOC Flux Rates from CAFO Manure and Wastewater  

Microsoft Academic Search

Wind tunnels and flux chambers are often used to measure volatile organic compound (VOC) emissions and estimate emission factors from animal feeding operations (AFOs) without regard to air velocity or sweep air flow rates. Laboratory experiments were conducted to evaluate the effect of wind tunnel air velocity on VOC emission rates. VOC emissions were measured on standard solutions of VOCs

David B. Parker; Edward Caraway; Marty Rhoades; Chanci Donnell; Jan Spears; N. Andy Cole; Richard W. Todd; Kenneth D. Casey

2008-01-01

188

Leaf-Level Controls Over Emissions of Methanol and 2-Methyl-3-buten-2-ol, Oxygenated VOC With Different Production Mechanisms and Solubilities.  

NASA Astrophysics Data System (ADS)

Oxygenated VOC fluxes were investigated in leaves of deciduous trees and grasses, and needles of conifers, using a temperature-controlled leaf cuvette and a proton transfer reaction mass spectrometer. Two alcohols, 2-methyl-3-buten-2-ol (MBO) and methanol, emitted by these plants, illustrate two contrasting patterns of oxygenated VOC emissions. MBO is restricted to a small section of the genus Pinus, and is maximal in mature needles. Methanol production appears to be ubiquitous among higher plants, associated with demethylation of pectin during cell wall maturation, and emissions are therefore maximal during rapid leaf growth, decreasing in mature leaves. Although emissions of both compounds respond to variation in leaf temperature and incident light, the nature of the control is quite different. Production and emission of MBO are tightly coupled, and leaf pools are small. Light and temperature affect emissions directly through their effect on production which ceases rapidly in the dark. Effects of light and temperature on production of methanol are unknown, although emissions, and presumably production, continue through the night at reduced rates. Effects of light and temperature on methanol emission are indirect, through their effects on stomatal conductance and evapotranspiration. Data will be presented to justify a conceptual model in which methanol released in the demethylation of pectin partitions into the gas and liquid phase according to Henry's Law. Gas phase methanol is then emitted through the stomata. However, methanol emissions correlate more strongly with rates of evapotranspiration than with stomatal conductance, suggesting that much of the methanol is released from the dissolved pool along with the transpiration stream. At night, when stomatal conductance is low, and assuming constant production, gas phase concentrations increase, and the size of the aqueous pool increases in response. This aqueous pool then empties rapidly upon stomatal opening, correlating strongly with rates of transpiration. Following depletion of the pool, lower methanol emissions reflect a dynamic balance between rates of production, phase partitioning, stomatal conductance and transpiration.

Harley, P. C.; Greenberg, J. P.; Guenther, A. B.

2002-12-01

189

[Volatile organic compounds (VOCs) emitted from large furniture].  

PubMed

Indoor air pollution by volatile organic compounds (VOCs), which may cause a hazardous influence on human being such as sick building (sick house) syndrome, has become a serious problem. In this study, VOCs emitted from nine pieces of home furniture, three sets of dining tables, three sets of chest of drawers and three sofas, were analyzed as potential sources of indoor air pollution by large chamber test method (JIS A 1911). Based on the emission rates of total VOC (TVOC), the impacts on the indoor TVOC was estimated by the sample model with a volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in three sets of dining tables, one set of chest of drawer and one sofa. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table, two sets of chest of drawers and one sofa. These results revealed that VOC emissions from furniture may influence significantly indoor air quality. Also, in this study, to establish the alternative method for large chamber test methods, emission rates from representative three parts of furniture unit were evaluated using the small chamber and emission rate from full-sized furniture was predicted. Emission rates of TVOC and formaldehyde predicted by small chamber test were 3-46% and 6-252% of the data obtained using large chamber test, respectively. PMID:22259846

Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Jinno, Hideto; Nishimura, Tetsuji

2011-01-01

190

Static SPME sampling of VOCs emitted from indoor building materials: prediction of calibration curves of single compounds for two different emission cells.  

PubMed

Solid-phase microextraction (SPME) is a powerful technique, easy to implement for on-site static sampling of indoor VOCs emitted by building materials. However, a major constraint lies in the establishment of calibration curves which requires complex generation of standard atmospheres. Thus, the purpose of this paper is to propose a model to predict adsorption kinetics (i.e., calibration curves) of four model VOCs. The model is based on Fick's laws for the gas phase and on the equilibrium or the solid diffusion model for the adsorptive phase. Two samplers (the FLEC® and a home-made cylindrical emission cell), coupled to SPME for static sampling of material emissions, were studied. A good agreement between modeling and experimental data is observed and results show the influence of sampling rate on mass transfer mode in function of sample volume. The equilibrium model is adapted to quite large volume sampler (cylindrical cell) while the solid diffusion model is dedicated to small volume sampler (FLEC®). The limiting steps of mass transfer are the diffusion in gas phase for the cylindrical cell and the pore surface diffusion for the FLEC®. In the future, this modeling approach could be a useful tool for time-saving development of SPME to study building material emission in static mode sampling. PMID:21400078

Mocho, Pierre; Desauziers, Valérie

2011-05-01

191

Observational Evaluation of Mobile Source Emissions  

NASA Astrophysics Data System (ADS)

Ambient ratios of NOx, CO, and CO2 sampled by aircraft in Houston and Dallas during the 2000 and 2006 Texas Air Quality Study (TexAQS) are compared with each other and with observations at a Houston highway tunnel. From these measurements we estimate 2000 and 2006 emissions for Houston and Dallas mobile sources. The observations demonstrate time-of-day variations in the relative contributions from gasoline and diesel combustion which are consistent with known traffic patterns. We incorporate CO2 emissions derived from the Federal Highway Administration's motor vehicle fuel use statistics into the EPA's National Emission Inventory (NEI), resulting in an emission data set for NOx, CO, and CO2 with 4-km spatial and hourly temporal resolution. Comparison of the emission ratios derived from the TexAQS observations with this inventory allows a direct evaluation of the NEI mobile source NOx and CO emissions.

Frost, G. J.; McKeen, S.; Trainer, M.; Aikin, K.; Peischl, J.; Ryerson, T.; Holloway, J.; Petron, G.; Tans, P.; Harley, R.

2007-12-01

192

Volatile organic compound concentrations, emission rates, and source apportionment in newly-built apartments at pre-occupancy stage.  

PubMed

The present study investigated the indoor concentrations of selected volatile organic compounds (VOCs) and formaldehyde and their indoor emission characteristics in newly-built apartments at the pre-occupancy stage. In total, 107 apartments were surveyed for indoor and outdoor VOC concentrations in two metropolitan cities and one rural area in Korea. A mass balanced model was used to estimate surface area-specific emission rates of individual VOCs and formaldehyde. Seven (benzene, ethyl benzene, toluene, m,p-xylene, o-xylene, n-hexane, and n-heptane) of 40 target compounds were detectable in all indoor air samples, whereas the first five were detected in all outdoor air samples. Formaldehyde was also predominant in the indoor air samples, with a high detection frequency of 96%. The indoor concentrations were significantly higher than the outdoor concentrations for aromatics, alcohols, terpenes, and ketones. However, six halogenated VOCs exhibited similar concentrations for indoor and outdoor air samples, suggesting that they are not major components emitted from building materials. It was also suggested that a certain portion of the apartments surveyed were constructed by not following the Korean Ministry of Environment guidelines for formaldehyde emissions. Toluene exhibited the highest emission rate with a median value of 138 ?g m(-2) h(-1). The target compounds with median emission rates greater than 20 ?g m(-2) h(-1) were toluene, 1-propanol, formaldehyde, and 2-butanone. The wood panels/vinyl floor coverings were the largest indoor pollutant source, followed by floorings, wall coverings, adhesives, and paints. The wood panels/vinyl floor coverings contributed nearly three times more to indoor VOC concentrations than paints. PMID:22698369

Shin, Seung H; Jo, Wan K

2012-10-01

193

CONTROLLING NOX EMISSION FROM INDUSTRIAL SOURCES  

EPA Science Inventory

A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx ...

194

INSTRUMENTAL SENSING OF STATIONARY SOURCE EMISSIONS  

EPA Science Inventory

Remote sensing methods offer a number of advantages over contact measurement methods in the area of enforcement and surveillance of emissions from stationary sources. Several techniques have been developed that can measure the gas concentration, effluent velocity, and particulate...

195

SOURCE ASSESSMENT: PHTHALIC ANHYDRIDE (AIR EMISSIONS)  

EPA Science Inventory

The report gives results of an analysis of atmospheric (air) emissions from ortho-xylene- and naphthalene-based phthalic anhydride manufacturing plants. Uncontrolled and controlled emission factors are given for each species emitted to the atmosphere from each source within a typ...

196

SOURCE ASSESSMENT: ACRYLONITRILE MANUFACTURE (AIR EMISSIONS)  

EPA Science Inventory

The report gives results of an analysis of atmospheric emissions from propylene-based acrylonitrile manufacturing plants. Uncontrolled and controlled emission factors are given for each species emitted to the atmosphere from each source within a typical plant, based on field samp...

197

Evaluation of formaldehyde and VOCs emission factors from paints in a small chamber: the effects of preconditioning time and coating weight.  

PubMed

The aims of this study were to improve the emission test method for the 20 L small chamber standardized in Korea using paints and to develop an optical test method for paints. The emission factors of the total volatile organic compounds (TVOC) and formaldehyde from oil-based paints, emulsion paints and water-dispersion paints coated at 300 g/m(2) and cured for 24 (48)h were determined using the 20 L small chamber method. The emission factors of TVOC and formaldehyde from all paints under steady state conditions were determined after 7 days with 24 (48)h of curing. The Korean standards require that paints be measured and analyzed on the third day after a test. However, the emission factors of TVOC and formaldehyde from the paints only began to stabilize 7 days after installing the samples. Until now, the emission test results have been reported mainly as concentration vs. time or emission factor vs. time profiles of TVOC and formaldehyde. The emission factors of the target volatile organic compounds (VOCs) and aldehyde types were obtained under specific test conditions according to the different coating weights. For all target volatile organic compounds and aldehyde types examined, the paint coating weight had an effect on emission. PMID:21112140

Kim, Jin-A; Kim, Sumin; Kim, Hyun-Joong; Kim, Yong-Shik

2011-03-15

198

CRITICAL EVALUATION OF THE DIFFUSION HYPOTHESIS IN THE THEORY OF POROUS MEDIA VOLATILE ORGANIC COMPOUND (VOC) SOURCES AND SINKS  

EPA Science Inventory

The paper proposes three alternative, diffusion-limited mathematical models to account for volatile organic compound (VOC) interactions with indoor sinks, using the linear isotherm model as a reference point. (NOTE: Recent reports by both the U.S. EPA and a study committee of the...

199

Self-regenerative field emission source  

NASA Astrophysics Data System (ADS)

A self-regenerative field emission source was demonstrated. The emission source (cathode) consisted of carbon nanofibers (CNFs) grown on the tip of conical carbon protrusions on a graphite plate. CNFs were ~25 nm in diameter, 0.3-2.5 ?m in length and ~1×106 mm-2 in site density. Initial emission characteristics showed a threshold field of 3.05 V/?m with a current density of 1 ?A/cm2 and a field enhancement factor of 2860 from the Fowler-Nordheim plot assuming the work function of 4.6 eV for graphite. A lifetime test carried out for more than 40 h at a constant applied electric field of 10 V/?m in 10-4 Pa region disclosed a stable emission with a current density of 1.7-3.0×10-4 A/cm2 after a slight initial decrease in the emission current. Detailed morphological observations revealed that a thick layer of newly grown carbon fibers was formed on the cathode surface after the lifetime test which could be responsible for the observed stable and long-sustained emission under a nonultrahigh vacuum condition. Their growth was attributed to the surface diffusion of carbon atoms generated by sputtering of the carbon cathode with ionized residual gas molecules during the field emission process. Thus, the CNF-tipped carbon emitter was believed to be promising as a practical field electron emission source used under low vacuum.

Tanemura, Masaki; Tanaka, J.; Itoh, K.; Okita, T.; Miao, L.; Tanemura, S.; Lau, S. P.; Huang, L.; Agawa, Y.; Kitazawa, M.

2005-11-01

200

Aerostat-lofted instrument and sampling method for determination of emissions from open area sources.  

PubMed

An aerostat-borne instrument and sampling method was developed to characterize air samples from area sources, such as emissions from open burning. The 10 kg battery-powered instrument system, termed "the Flyer", is lofted with a helium-filled aerostat of 4m nominal diameter and maneuvered by means of one or two tethers. The Flyer can be configured variously for continuous CO? monitoring, batch sampling of semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs), black carbon, metals, and PM by size. The samplers are controlled by a trigger circuit to avoid unnecessary dilution from background sampling when not within the source plume. The aerostat/Flyer method was demonstrated by sampling emissions from open burning (OB) and open detonation (OD) of military ordnance. A carbon balance approach was used to derive emission factors that showed excellent agreement with published values. PMID:21840564

Aurell, Johanna; Gullett, Brian K; Pressley, Christopher; Tabor, Dennis G; Gribble, Robert D

2011-10-01

201

Jovian S emission: Model of radiation source  

NASA Astrophysics Data System (ADS)

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

Ryabov, B. P.

1994-04-01

202

Volatile emissions from wastewater are regulated, too  

SciTech Connect

Increasing concern about the health effects of volatile organic compounds (VOCs) in air has resulted in a comprehensive attempt to regulate all sources of VOC emissions. Several recent regulatory initiatives address not only industrial processes that emit VOCs, but waste streams including process wastewater. Until recently, facilities could discharge aqueous waste streams that contained VOCs to publicly owned treatment works (POTWs), or to onsite treatment or pretreatment facilities, with no regard as to whether those processes treated the VOCs or simply vented them to the atmosphere. With several recent regulatory initiatives--the Benzene in Waste Operations National Emissions Standards for Hazardous Air Pollutants (Neshap) and the Hazardous Organics Neshap (HONM; box, right)--US regulators have begun targeting wastewater as a source of air emissions. Such agencies are continuing to develop a multimedia approach to eliminate the discharge of VOCs to the atmosphere.

Jagiella, T.C. (Environmental Science Engineering, Inc., Peoria, IL (United States)); Klickman, M.W. (Environmental Science Engineering, Inc., Chicago, IL (United States))

1994-06-01

203

Modeling Secondary Organic Aerosol Formation From Emissions of Combustion Sources  

NASA Astrophysics Data System (ADS)

Atmospheric aerosols exert a large influence on the Earth's climate and cause adverse public health effects, reduced visibility and material degradation. Secondary organic aerosol (SOA), defined as the aerosol mass arising from the oxidation products of gas-phase organic species, accounts for a significant fraction of the submicron atmospheric aerosol mass. Yet, there are large uncertainties surrounding the sources, atmospheric evolution and properties of SOA. This thesis combines laboratory experiments, extensive data analysis and global modeling to investigate the contribution of semi-volatile and intermediate volatility organic compounds (SVOC and IVOC) from combustion sources to SOA formation. The goals are to quantify the contribution of these emissions to ambient PM and to evaluate and improve models to simulate its formation. To create a database for model development and evaluation, a series of smog chamber experiments were conducted on evaporated fuel, which served as surrogates for real-world combustion emissions. Diesel formed the most SOA followed by conventional jet fuel / jet fuel derived from natural gas, gasoline and jet fuel derived from coal. The variability in SOA formation from actual combustion emissions can be partially explained by the composition of the fuel. Several models were developed and tested along with existing models using SOA data from smog chamber experiments conducted using evaporated fuel (this work, gasoline, fischertropschs, jet fuel, diesels) and published data on dilute combustion emissions (aircraft, on- and off-road gasoline, on- and off-road diesel, wood burning, biomass burning). For all of the SOA data, existing models under-predicted SOA formation if SVOC/IVOC were not included. For the evaporated fuel experiments, when SVOC/IVOC were included predictions using the existing SOA model were brought to within a factor of two of measurements with minor adjustments to model parameterizations. Further, a volatility-only model suggested that differences in the volatility of the precursors were able to explain most of the variability observed in the SOA formation. For aircraft exhaust, the previous methods to simulate SOA formation from SVOC and IVOC performed poorly. A more physically-realistic modeling framework was developed, which was then used to show that SOA formation from aircraft exhaust was (a) higher for petroleum-based than synthetically derived jet fuel and (b) higher at lower engine loads and vice versa. All of the SOA data from combustion emissions experiments were used to determine source-specific parameterizations to model SOA formation from SVOC, IVOC and other unspeciated emissions. The new parameterizations were used to investigate their influence on the OA budget in the United States. Combustion sources were estimated to emit about 2.61 Tg yr-1 of SVOC, 1VOC and other unspeciated emissions (sixth of the total anthropogenic organic emissions), which are predicted to double SOA production from combustion sources in the United States. The contribution of SVOC and IVOC emissions to global SOA formation was assessed using a global climate model. Simulations were performed using a modified version of GISS GCM 11'. The modified model predicted that SVOC and IVOC contributed to half of the OA mass in the atmosphere. Their inclusion improved OA model-measurement comparisons for absolute concentrations, POA-SOA split and volatility (gas-particle partitioning) globally suggesting that atmospheric models need to incorporate SOA formation from SVOC and IVOC if they are to reasonably predict the abundance and properties of aerosols. This thesis demonstrates that SVOC/IVOC and possibly other unspeciated organics emitted by combustion sources are very important precursors of SOA and potentially large contributors to the atmospheric aerosol mass. Models used for research and policy applications need to represent them to improve model-predictions of aerosols on climate and health outcomes. The improved modeling frameworks developed in this dissertation are suitable for implementa

Jathar, Shantanu Hemant

204

Mercury emissions from industrial sources in China  

Microsoft Academic Search

In this chapter, we reviewed mercury emissions from industrial sources in China. The industrial sources included fuel oil\\u000a for stationary sources; gasoline; diesel and kerosene; biofuel combustion; Grassland\\/ savannah burning; waste and residue\\u000a burning; cement production; iron and steel production; caustic soda production; non-ferrous metal smelting (Zn, Pb, Cu, and\\u000a Au); mercury mining; and battery and fluorescent lamp production. Mercury

Xinbin Feng; David Streets; Jiming Hao; Ye Wu; Guanghui Li

205

Emission factors from aerial and ground measurements of field and laboratory forest burns in the southeastern US: PM2.5, black and brown carbon, VOC, and PCDD/PCDF.  

PubMed

Aerial- and ground-sampled emissions from three prescribed forest burns in the southeastern U.S. were compared to emissions from laboratory open burn tests using biomass from the same locations. A comprehensive array of emissions, including PM2.5, black carbon (BC), brown carbon (BrC), carbon dioxide (CO2), volatile organic compounds (VOCs), and polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were sampled using ground-based and aerostat-lofted platforms for determination of emission factors. The PM2.5 emission factors ranged from 14 to 47 g/kg biomass, up to three times higher than previously published studies. The biomass type was the primary determinant of PM2.5, rather than whether the emission sample was gathered from the laboratory or the field and from aerial- or ground-based sampling. The BC and BrC emission factors ranged from 1.2 to 2.1 g/kg biomass and 1.0 to 1.4 g/kg biomass, respectively. A decrease in BC and BrC emission factors with decreased combustion efficiency was found from both field and laboratory data. VOC emission factors increased with decreased combustion efficiency. No apparent differences in averaged emission factors were observed between the field and laboratory for BC, BrC, and VOCs. The average PCDD/PCDF emission factors ranged from 0.06 to 4.6 ng TEQ/kg biomass. PMID:23895511

Aurell, Johanna; Gullett, Brian K

2013-08-01

206

Membrane systems for profitable VOC recovery  

Microsoft Academic Search

VOC emissions from all types of vents, processing streams, or leaks will have to be reduced during the next few years. Several established technologies (including carbon adsorption, condensation, or incineration) can be used to destroy or remove VOCs from air streams, but no single technology meets every need. Membrane-based vapor separation, developed during the past 10 years, is beginning to

R. W. Baker; J. Kaschemekat; J. G. Wijmans

1996-01-01

207

ENDOCRINE DISRUPTING CHEMICAL EMISSIONS FROM COMBUSTION SOURCES: DIESEL PARTICULATE EMISSIONS AND DOMESTIC WASTE OPEN BURN EMISSIONS  

EPA Science Inventory

Emissions of endocrine disrupting chemicals (EDCs) from combustion sources are poorly characterized due to the large number of compounds present in the emissions, the complexity of the analytical separations required, and the uncertainty regarding identification of chemicals with...

208

IMPROVING EMISSIONS ESTIMATES WITH COMPUTATIONAL INTELLIGENCE, DATABASE EXPANSION, AND COMPREHENSIVE VALIDATION  

EPA Science Inventory

The report discusses an EPA investigation of techniques to improve methods for estimating volatile organic compound (VOC) emissions from area sources. Using the automobile refinishing industry for a detailed area source case study, an emission estimation method is being developed...

209

Modeling VOC transport in simulated waste drums  

SciTech Connect

A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the VOC permeability had been measured. Permeabilities for five VOCs [methylene chloride, 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113), 1,1,1-trichloroethane, carbon tetrachloride, and trichloroethylene] were measured across a polyethylene bag. Comparison of model and experimental results of VOC concentration as a function of time indicate that model accurately accounts for significant VOC transport mechanisms in a lab-scale waste drum.

Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

1993-06-01

210

MEASUREMENT OF PCB EMISSIONS FROM COMBUSTION SOURCES  

EPA Science Inventory

The report describes a gas chromatographic/mass spectrometric (GC/MS) procedure that overcomes problems encountered when using GC procedures (previously used to determine polychlorinated biphenyls (PCBs) in solids and water) on emissions from combustion sources. The GC/MS procedu...

211

Controlling NOx emission from industrial sources  

Microsoft Academic Search

A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other

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

2005-01-01

212

Guide to state stationary source emission standards  

Microsoft Academic Search

State emission standards are listed for the following sources: fossil-fuel burning equipment; process industries; sulfuric acid plants; nitric acid plants; hot mix asphalt plants; chemical fertilizer plants; petroleum refineries; sulfur recovery plants; ferrous and nonferrous foundries; sintering plants, blast furnaces, and basic oxygen furnaces; primary aluminum plants and secondary metals operations; kraft pulp mills; sulfite pulp mills; Portland cement plants;

Abel

1974-01-01

213

Synchro-Compton emission from superluminal sources  

NASA Technical Reports Server (NTRS)

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

Marscher, Alan P.

1987-01-01

214

Characterizing the chemical evolution of air masses via multi-platform measurements of volatile organic compounds (VOCs) during CalNEX: Composition, OH reactivity, and potential SOA formation  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) are critical components in the photochemical production of ozone (O3) and secondary organic aerosol (SOA). During the CalNex 2010 field campaign, an extensive set of VOCs were measured at the Pasadena ground site, and aboard the NOAA WP-3D aircraft and the WHOI Research Vessel Atlantis. The measurements from each platform provide a unique perspective into the emissions, transport, and atmospheric processing of VOCs within the South Coast Air Basin (SoCAB). The observed enhancement ratios of the hydrocarbons measured on all three platforms are in good agreement and are generally well correlated with carbon monoxide (CO), indicating the prevalence of on-road VOC emission sources throughout the SoCAB. Offshore measurements aboard the ship and aircraft are used to characterize the air mass composition as a function of the land/sea-breeze effect. VOC ratios and other trace gases are used to identify air masses containing relatively fresh emissions that were often associated with offshore flow and re-circulated continental air associated with onshore flow conditions. With the prevailing southwesterly airflow pattern in the LAB throughout the daytime, the Pasadena ground site effectively functions as a receptor site and is used to characterize primary VOC emissions from downtown Los Angeles and to identify the corresponding secondary oxidation products. The chemical evolution of air masses as a function of the time of day is investigated in order to determine the relative impacts of primary emissions vs. secondary VOC products on OH reactivity and potential SOA formation. The reactivity of VOCs with the hydroxyl radical (OH) at the Pasadena site was dominated by the light hydrocarbons, isoprene, and oxygenated VOCs including aldehydes (secondary products) and alcohols (primary anthropogenic emissions). Toluene and benzaldehyde, both of which are associated with primary anthropogenic emissions, are the predominant VOC precursors to the potential formation of SOA.

Gilman, J. B.; Kuster, W. C.; Bon, D.; Warneke, C.; Lerner, B. M.; Williams, E. J.; Holloway, J. S.; Pollack, I. B.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Herndon, S. C.; Zahniser, M. S.; Vlasenko, A. L.; Li, S.; Alvarez, S. L.; Rappenglueck, B.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; De Gouw, J. A.

2011-12-01

215

Evaluation of low-VOC latex paints  

SciTech Connect

The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that the VOC contents of all four paints are considerably lower than those of conventional latex paints. Low-VOC emissions were confirmed by small chamber emission tests. However, sigificant emissions of several aldehydes, especially formaldehyde, were detected from two of the paints. ASTM methods were used to evaluate the hiding power, scrubbability, washability, dry to touch, and yellowing index. The results indicated that one of the low-VOC paints tested showed performance equivalent or superior to that of a widely used conventional latex paint used as a control. It was concluded that low-VOC latex paint can be a viable option to replace conventional latex paints for prevention of indoor air pollution. However, paints marketed as low-VOC may still have significant emissions of some individual VOCs, and some may not have performance characteristics matching those of conventional latex paints.

Chang, J.C.S.; Fortmann, R.C.; Roache, N.F.; Lao, H.C.

1999-11-01

216

Evaluation of low-VOC latex paints  

SciTech Connect

The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that the VOC contents of all four paints are considerably lower than those of conventional latex paints. Low-VOC emissions were confirmed by small chamber emission tests. However, sigificant emissions of several aldehydes, especially formaldehyde, were detected from two of the paints. ASTM methods were used to evaluate the hiding power, scrubbability, washability, dry to touch, and yellowing index. The results indicated that one of the low-VOC paints tested showed performance equivalent or superior to that of a widely used conventional latex paint used as a control. It was concluded that low-VOC latex paint can be a viable option to replace conventional latex paints for prevention of indoor air pollution. However, paints marketed as low-VOC may still have significant emissions of some individual VOCs, and some may not have performance characteristics matching those of conventional latex paints.

Chang, J.C.S.; Fortmann, R.C.; Roache, N.F.; Lao, H.C.

1999-01-01

217

NOVEL NANOPARTICULATE CATALYSTS FOR IMPROVED VOC TREATMENT DEVICES - PHASE I  

EPA Science Inventory

Catalytic oxidation of VOCs is increasingly used for treatment of large-volume emissions at relatively dilute VOC levels. The best performing catalytic oxidation devices for attainment of very high VOC destruction levels employ precious metal catalysts, the costs of which a...

218

Fugitive Emission Sources and Batch Operations in Synthetic Organic Chemical Production.  

National Technical Information Service (NTIS)

This survey report was developed for the EPA for use in assessing the potential magnitude of fugitive volatile organic compound (VOC) emissions from agitator seals, cooling towers and batch operations in the production of 378 designated chemicals. The inf...

D. G. Erikson F. D. Hobbs O. D. Ivins V. Kalcevic W. L. Troxler

1981-01-01

219

Volatile organic compound emissions from the oil and natural gas industry in the Uinta Basin, Utah: point sources compared to ambient air composition  

NASA Astrophysics Data System (ADS)

The emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uinta Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aromatics, alkanes, cycloalkanes and methanol were observed for extended periods of time and short-term spikes caused by local point sources. The mixing ratios during the time the mobile laboratory spent on the well pads were averaged. High mixing ratios were found close to all point sources, but gas wells using dry-gas collection, which means dehydration happens at the well, were clearly associated with higher mixing ratios than other wells. Another large source was the flowback pond near a recently hydraulically re-fractured gas well. The comparison of the VOC composition of the emissions from the oil and natural gas wells showed that wet gas collection wells compared well with the majority of the data at Horse Pool and that oil wells compared well with the rest of the ground site data. Oil wells on average emit heavier compounds than gas wells. The mobile laboratory measurements confirm the results from an emissions inventory: the main VOC source categories from individual point sources are dehydrators, oil and condensate tank flashing and pneumatic devices and pumps. Raw natural gas is emitted from the pneumatic devices and pumps and heavier VOC mixes from the tank flashings.

Warneke, C.; Geiger, F.; Edwards, P. M.; Dube, W.; Pétron, G.; Kofler, J.; Zahn, A.; Brown, S. S.; Graus, M.; Gilman, J.; Lerner, B.; Peischl, J.; Ryerson, T. B.; de Gouw, J. A.; Roberts, J. M.

2014-05-01

220

EVALUATION OF LOW-VOC LATEX PAINTS  

EPA Science Inventory

The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that ...

221

Mapping and profile of emission sources for airborne volatile organic compounds from process regions at a petrochemical plant in Kaohsiung, Taiwan.  

PubMed

This work surveyed five process regions inside a petrochemical plant in Taiwan to characterize the profiles of airborne volatile organic compounds (VOCs) and locate emission sources. Samples, taken with canisters, were analyzed with gas chromatography-mass spectrometry according to the TO-14 method. Each region was deployed with 24 sampling sites, sampled twice, and 240 samples in total were measured during the survey period. All of the data were consolidated into a database on Excel to facilitate retrieval, statistical analysis, and presentation in the form of a table or graph, and, subsequently, the profile of VOCs was elucidated. Emission sources were located by mapping the concentration distribution of either an individual or a type of species in terms of contour maps on Surfer. Through the cross-analysis of data, the abundant VOCs included alkenes, dienes, alkanes, and aromatics. A total of 19 emission sources were located from these five regions. The sources for alkanes stood inside first, third aromatic, and fourth naphtha cracking regions, whereas the ones for alkenes were inside two naphtha cracking regions. The sources for dienes were found inside the third naphtha cracking region alone; in contrast, the sources for aromatics were universally traced except inside the third naphtha cracking region. The measured intensity for sources mostly ranged from 1000 to 7000 ppb. PMID:16805407

Chen, Ching-Liang; Fang, Hung-Yuan; Shu, Chi-Min

2006-06-01

222

Intelligent location of simultaneously active acoustic emission sources: Part I  

Microsoft Academic Search

Abstract, The intelligent acoustic emission locator is described in Part I, while Part II discusses blind source separation, time delay estimation and location of two simultaneously active continuous acoustic emission sources. The location of acoustic emission on complicated aircraft frame structures is a difficult problem of non-destructive testin g. This article describes an intelligent acoustic emission source locator. The intelligent

Tadej Kosel; Igor Grabec

2007-01-01

223

Emissions of volatile organic compounds during the decomposition of plant litter  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) are emitted during plant litter decomposition, and such VOCs can have wide-ranging impacts on atmospheric chemistry, terrestrial biogeochemistry, and soil ecology. However, we currently have a limited understanding of the relative importance of biotic versus abiotic sources of these VOCs and whether distinct types of litter emit different types and quantities of VOCs during decomposition. We analyzed VOCs emitted by microbes or by abiotic mechanisms during the decomposition of litter from 12 plant species in a laboratory experiment using proton transfer reaction mass spectrometry (PTR-MS). Net emissions from litter with active microbial populations (non-sterile litters) were between 0 and 11 times higher than emissions from sterile controls over a 20-d incubation period, suggesting that abiotic sources of VOCs are generally less important than biotic sources. In all cases, the sterile and non-sterile litter treatments emitted different types of VOCs, with methanol being the dominant VOC emitted from litters during microbial decomposition, accounting for 78 to 99% of the net emissions. We also found that the types of VOCs released during biotic decomposition differed in a predictable manner among litter types with VOC profiles also changing as decomposition progressed over time. These results show the importance of incorporating both the biotic decomposition of litter and the species-dependent differences in terrestrial vegetation into global VOC emission models.

Gray, Christopher M.; Monson, Russell K.; Fierer, Noah

2010-09-01

224

Volatile organic compound (VOC) analysis and sources of limonene, cyclohexanone and straight chain aldehydes in axenic cultures of Calothrix and Plectonema.  

PubMed

The volatile organic compounds (VOCs) in four standing cultures of axenic benthic cyanobacteria (Calothrix and Plectonema) were studied by GC/MS analysis. To verify the biogenic origin of the VOCs, 13C-labelling experiments were performed, and the differences in labelling were used to differentiate between biogenic and non-biogenic sources. Strongly labelled biogenic compounds were derived from the shikimate (cresol, skatole), isoprenoid (beta-cyclocitral, beta-ionone, geosmin) and fatty acid pathways (5Z-heptadecene, 3-octanone, 1-hexanol). New odour compounds derived from microorgansims were beta-cyclogeraniol, dihydro-beta-ionone and 2-hydroxy-2,6,6-trimethylcyclohexanone. The latter compound had already been found in lake water, but could not be assigned to a particular organism. Straight chain aldehydes (octanal, nonanal, decanal), cyclohexanone, cyclohexanol and limonene were unlabelled beyond their natural isotope ratio. Therefore, the biogenic origin of these compounds is doubtful despite their occurrence in axenic cultures. The observation that limonene was a racemate supports this view. The precursors and reactions that lead to the formation of these non-biogenic compounds are unknown and it may be that they are formed by the analytical procedures rather than then being present in the culture medium. PMID:15237606

Höckelmann, C; Jüttner, F

2004-01-01

225

Volcanic halogen emissions: sources and consequences  

NASA Astrophysics Data System (ADS)

We present an overview of our recent work concerning the sources of halogens in volcanic emissions; how inert hydrogen halides in volcanic gases become activated into environmentally reactive species, and some of the potential consequences of these species. Previous studies have suggested that the Cl in volcanic emissions is the result of efficient recycling of Cl taken down with the subducting slab. We will present new results from Nicaragua for volcanic Br and I emissions, as well as Cl. Our results are consistent with a subduction source for I. In general, the volcanic samples are more enriched in Cl than many other Earth system reservoirs. We will discuss some of the questions that this raises, and review the scale of global volcanic halogen emissions. Once emitted from the magma, volcanic halogen species may cause localised ozone depletion both in the troposphere (following activation by high-temperature mixing with atmospheric oxygen) and the stratosphere (due to their interactions with other volcanic plume components as shown in the recent studies of the Hekla plume in 2000).

Mather, T. A.; Pyle, D. M.; Aiuppa, A.; Millard, G. A.; Rose, W. I.; Martin, R. S.

2007-12-01

226

Sources of acoustic emission in superconducting magnets  

SciTech Connect

Origins of acoustic emission (AE) in superconducting wires have been investigated. Our experimental results indicate that wire motion is a dominant source of AE in current-carrying wires, both superconducting and nonsuperconducting. Furthermore, the results show that flux motion, except during flux jumping, produces no discernable acoustic signals. Both of these conclusions differ from the conclusions of earlier AE results which attributed the major source of AE signals in superconductors and superconducting magnets to flux motion. A simple model based on frictional sliding of conductor is presented to interpret acoustic data; agreement between theory and experiment is good.

Tsukamoto, O.; Iwasa, Y.

1983-02-01

227

Impacts of different emission sources on air quality during March 2001 in the Pearl River Delta (PRD) region  

NASA Astrophysics Data System (ADS)

This study focuses on the role played by emissions from transportation, industry and power generation on the concentrations of O 3, CO, NO, NO y and SO 2 in Guangdong province of China. Observational data of the pollutants and numerical modeling of atmospheric chemistry, transport and removal processes with STEM-2K1 and MM5 are used for March 2001. The objective is to identify the relative importance of the three emission sources on the concentrations of the pollutants. In addition, the relative importance of NO x and VOC emissions from the transportation sector for O 3 production is examined. The observations at a rural and an urban site in the region show distinctive characteristics, indicating the importance of local emissions. A comparison of the observed ratios of CO/NO x and SO 2/NO x at the two sites with those derived from the emission inventories show the usefulness of the emission inventories. A control simulation with all emissions included shows a fairly satisfactory performance of the model in terms of the comparison between the observed and modeled concentrations of CO, SO 2, NO y and O 3 at the rural site, although the observed extremes are less well simulated. Three simulations with different emission scenarios suggest that the transportation source was the main contributor to NO x, CO and O 3 concentrations accounting for 34.2%, 33.1% and 17.8% of their total concentrations, respectively. For SO 2 concentration, the main contributor is the power plant sources with a contribution rate of 32.9%. For SO 2, the doubling of emissions from the industry has a much larger effect on the ambient levels than the doubling from the transportation, whereas the increase in the transportation sector sources has approximately twice the effect of the increased industrial emission on O 3. The doubling of emissions from the transportation and industry sources would increase the O 3 concentration by about 26.7% and 8.5% for the whole region. Finally, the O 3/NO z ratio of 25 was found to be a reasonable threshold to separate NO x-limited and VOC-limited regimes concerning O 3 chemistry. It is found that the urban area is VOC-limited and the non-urban area is NO x-limited. These results have implications for O 3 control strategy for the region.

Wang, Xuemei; Carmichael, Gregory; Chen, Deliang; Tang, Youhua; Wang, Tijian

228

Impacts of seasonal and regional variability in biogenic VOC emissions on surface ozone in the Pearl River Delta region, China  

SciTech Connect

In this study, the BVOC emissions in November 2010 over the Pearl River Delta (PRD) region in southern China have been estimated by the latest version of a Biogenic Volatile Organic Compound (BVOC) emission model (MEGAN v2.1). The evaluation of MEGAN performance at a representative forest site within this region indicates MEGAN can estimate BVOC emissions reasonably well in this region except overestimating isoprene emission in autumn for reasons that are discussed in this manuscript. Along with the output from MEGAN, the Weather Research and Forecasting model with chemistry (WRF-Chem) is used to estimate the impacts of BVOC emissions on surface ozone in the PRD region. The results show BVOC emissions increase the daytime ozone peak by *3 ppb on average, and the max hourly impacts of BVOC emissions on the daytime ozone peak is 24.8 ppb. Surface ozone mixing ratios in the central area of Guangzhou- Foshan and the western Jiangmen are most sensitive to BVOC emissions BVOCs from outside and central PRD influence the central area of Guangzhou-Foshan and the western Jiangmen significantly while BVOCs from rural PRD mainly influence the western Jiangmen. The impacts of BVOC emissions on surface ozone differ in different PRD cities, and the impact varies in different seasons. Foshan and Jiangmen being most affected in autumn, result in 6.0 ppb and 5.5 ppb increases in surface ozone concentrations, while Guangzhou and Huizhou become more affected in summer. Three additional experiments concerning the sensitivity of surface ozone to MEGAN input variables show that surface ozone is more sensitive to landcover change, followed by emission factors and meteorology.

Situ, S.; Guenther, Alex B.; Wang, X. J.; Jiang, X.; Turnipseed, A.; Wu, Z.; Bai, J.; Wang, X.

2013-12-05

229

Summary of Emissions Associated with Sources of Ethyl Chloride,  

National Technical Information Service (NTIS)

The potential ambient health impact of ethyl chloride emissions has been investigated. The document contains information on the sources of ethyl chloride emissions, estimates current emission levels, summarizes production trends and ambient monitoring res...

G. L. Hume

1988-01-01

230

World Calibration Center for VOC (WCC-VOC), a new Facility for the WMO-GAW-Programme  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOC) are recognized to be important precursors of tropospheric ozone as well as other oxidants and organic aerosols. In order to design effective control measures for the reduction of photooxidants, photochemical processes have to be understood and the sources of the precursors known. Reliable and representative measurements of VOCs are necessary to describe the anthropogenic and biogenic sources, to follow the photochemical degradation of VOCs in the troposphere. Measurement of VOCs is of key importance for the understanding of tropospheric chemistry. Tropospheric VOCs have been one of the recommended measurements to be made within the GAW programme. The purpose will be to monitor their atmospheric abundance, to characterize the various compounds with regard to anthropogenic and biogenic sources and to evaluate their role in the tropospheric ozone formation process. An international WMO/GAW panel of experts for VOC measurements developed the rational and objectives for this GAW activity and recommended the configuration and required activities of the WCC-VOC. In reflection of the complexity of VOC measurements and the current status of measurement technology, a "staged" approach was adopted. Stage 1 measurements: C2-C9 hydrocarbons, including alkanes, alkenes, alkynes, dienes and monocyclics. (The WCC-VOC operates currently under this mode). Stage 2 measurements: C10-C14 hydrocarbons, including higher homologs of the Stage 1 set as well as biogenic hydrocarbon compounds. Stage 3 measurements: Oxygenated VOCs, including alcohols, carbonyls, carboxylic acids. The Quality Assurance/Science Activity Centre (QA/SAC) Germany currently has established the World Calibration Centre for VOC (WCC-VOC). The WCC-VOC has operated in the research mode und has become operational recently. From now on, the WCC-VOC conducts one round-robin calibration audit per year at all global stations that measure VOCs and assists other stations in setting up VOC measurement capabilities. Furthermore, the WCC-VOC will promote inter-com-parison experiments with networks related to other programmes, notably EMEP and IGAC.

Rappenglueck, B.-

2002-12-01

231

Effect of Fuel Gas Composition and Excess Air on VOC Emissions from a Small-Scale, Industrial-Style Burner  

Microsoft Academic Search

Furnace-out emissions of benzene, toluene, cthylbenzene, and the xylenes have been measured for a research-grade, industrial-style diffusion flame burner operating under well-controlled conditions representative of refinery process heaters. Flame structure was also evaluated by means of visible emission imaging. Excess air was varied from 50% to sub-stoichiometric, The fuels were methane and blends of methane, hydrogen, and propane used to

C. F. Edwards; P. J. Goix

1996-01-01

232

Eddy Flux and Leaf-level Measurements of Biogenic VOC Emissions from two Savannas in Southern Africa  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compound (BVOC) emissions of isoprene and terpenes were measured in 2 savannas of southern Africa: a mopane woodland (>95% Colophospermum mopane), near Maun, Botswana and a Combretum savanna (45% Combretum apiculatum, the remainder mostly Acacia nilotica, Zizphus mucronata, Sclerocarya birrea, Grewia bicolor, and Acacia nigrescens), near Skukuza, Republic of South Africa. These 2 landscapes contain most of the dominant woody plant species found in southern Africa; mopane woodlands are a monospecific landscape occurring over a large area across southern Africa. These studies were made in January-February 2001 as part of SAFARI 2000. Over 100 species were examined at the leaf level using cuvette techniques. In addition, relaxed eddy accumulation measurements of BVOC fluxes were made on towers in each location. Large, light dependent emissions of terpenes (mostly alpha-pinene) were observed from mopane. Of the major species in the Combretum savanna, only Acacia nigrescens emitted significant amounts of isoprene; none emitted terpenes. However, several minor species (Lonchocarpus capassa, Spirostachys africana) emitted isoprene. Net CO2 emissions were measured simultaneously on each tower; the diurnal BVOC emissions were integrated and compared with net CO2 flux measurements made simultaneously on the same tower. The contribution of these and other BVOC emissions to net ecosystem carbon exchange will be discussed. In addition, the implications of these emissions to regional atmospheric chemistry and landscape change will be examined.

Greenberg, J.; Guenther, A.; Harley, P.; Otter, L.; Veenendaal, E.; Hewitt, N.; James, T.; Owens, S.

2001-12-01

233

Source apportionment of volatile organic compounds in Hong Kong homes  

Microsoft Academic Search

Indoor volatile organic compound (VOC) data obtained in 100 Hong Kong homes were analyzed to investigate the nature of emission sources and their contributions to indoor concentrations. A principal component analysis (PCA) showed that off-gassing of building materials, household products, painted wood products, room freshener, mothballs and consumer products were the major sources of VOCs in Hong Kong homes. The

H. Guo

2011-01-01

234

Emission source functions in heavy ion collisions  

NASA Astrophysics Data System (ADS)

Three-dimensional pion and kaon emission source functions are extracted from hydrokinetic model (HKM) simulations of central Au+Au collisions at the top Relativistic Heavy Ion Collider (RHIC) energy sNN=200 GeV. The model describes well the experimental data, previously obtained by the PHENIX and STAR collaborations using the imaging technique. In particular, the HKM reproduces the non-Gaussian heavy tails of the source function in the pair transverse momentum (out) and beam (long) directions, observed in the pion case and practically absent for kaons. The role of rescatterings and long-lived resonance decays in forming the mentioned long-range tails is investigated. The particle rescattering contribution to the out tail seems to be dominating. The model calculations also show substantial relative emission times between pions (with mean value 13 fm/c in the longitudinally comoving system), including those coming from resonance decays and rescatterings. A prediction is made for the source functions in Large Hadron Collider (LHC) Pb+Pb collisions at sNN=2.76 TeV, which are still not extracted from the measured correlation functions.

Shapoval, V. M.; Sinyukov, Yu. M.; Karpenko, Iu. A.

2013-12-01

235

40 CFR 60.694 - Permission to use alternative means of emission limitation.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for VOC Emissions From Petroleum Refinery Wastewater Systems § 60.694 Permission to use alternative means of emission limitation. (a) If, in the...

2013-07-01

236

Variations in amounts and potential sources of volatile organic chemicals in new cars.  

PubMed

This study examines inter-brand, intra-brand and intra-model variations in volatile organic chemical (VOC) levels inside new cars. The effect of temperature on interior VOC levels was examined using model automobiles with and without the air-conditioning running. Potential sources of VOC were assessed by comparing VOC levels with two interior trims (leather and fabric) and by analyzing VOC emissions from various interior components. Five brands of new car, both domestic and imported, were tested. Twelve targeted VOCs were collected on solid sorbents and analyzed using thermal desorption and GC/FID. VOCs from interior parts and adhesives were identified using solid phase micro-extraction (SPME) coupled with GC/MS. The VOC concentrations varied markedly among brands and within models, and individual VOC levels ranged from below the detection limit (a few mug per cubic meter) to thousands of mug per cubic meter. The intra-model variability (mean, 47%) in the VOC levels was approximately 50% that within each brand (mean, 95%). Although interior trim levels affected VOC levels, the effects differed among brands. Reduction of the cabin temperature reduced most VOC levels, but the impact was not statistically significant. Screening tests for VOCs from interior parts revealed that butylated hydroxytoluene (BHT), a common anti-oxidant, was the most common chemical. Long-chain aliphatic hydrocarbons, particularly C14-C17, were identified in most grease (lubricant) samples, and toluene and xylenes were ubiquitously present in adhesive samples. Process-related compounds, such as plasticizer, were also identified in interior parts. In-cabin VOC levels varied significantly among makes/models and interior trims. Concerned consumers should purchase older new cars from manufacturers since VOC levels inside car cabins normally declines over time. Improved processes or materials with lower VOC emission potential should be used to minimize in-cabin VOC sources for new cars. PMID:17540434

Chien, Yeh-Chung

2007-09-01

237

Comparative study on indoor air quality in Japan and China: Characteristics of residential indoor and outdoor VOCs  

NASA Astrophysics Data System (ADS)

We conducted a comparative study on the indoor air quality for Japan and China to investigate aromatic volatile organic compounds (VOCs) in indoor microenvironments (living room, bedroom, and kitchen) and outdoors in summer and winter during 2006-2007. Samples were taken from Shizuoka in Japan and Hangzhou in China, which are urban cities with similar latitudes. Throughout the samplings, the indoor and outdoor concentrations of many of the targeted VOCs (benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes) in China were significantly higher than those in Japan. The indoor concentrations of VOCs in Japan were somewhat consistent with those outdoors, whereas those in China tended to be higher than those outdoors. Here, we investigated the differences in VOC concentrations between Japan and China. Compositional analysis of indoor and outdoor VOCs showed bilateral differences; the contribution of benzene in China was remarkably higher than that in Japan. Significant correlations ( p < 0.05) for benzene were observed among the concentrations in indoor microenvironments and between the outdoors and living rooms or kitchens in Japan. In China, however, significant correlations were observed only between living rooms and bedrooms. These findings suggest differences in strengths of indoor VOC emissions between Japan and China. The source characterizations were also investigated using principal component analysis/absolute principal component scores. It was found that outdoor sources including vehicle emission and industrial sources, and human activity could be significant sources of indoor VOC pollution in Japan and China respectively. In addition, the lifetime cancer risks estimated from unit risks and geometric mean indoor concentrations of carcinogenic VOCs were 2.3 × 10 -5 in Japan and 21 × 10 -5 in China, indicating that the exposure risks in China were approximately 10 times higher than those in Japan.

Ohura, Takeshi; Amagai, Takashi; Shen, Xueyou; Li, Shuang; Zhang, Ping; Zhu, Lizhong

2009-12-01

238

The Sensitivity of U.S. Surface Ozone Formation to NOx, and VOCs as Viewed from Space  

NASA Technical Reports Server (NTRS)

We investigated variations in the sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NO(x)) as inferred from the ratio of tropospheric columns of formaldehyde and nitrogen dioxide from the Aura Ozone Monitoring Instrument (OMI). The data indicate that ozone formation became: 1. more sensitive to NO(x) over most of the U.S, from 2005 to 2007 because of substantial decreases in NO(x) emissions primarily from stationary sources, and 2. more sensitive to NO(x) with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. Based on our interpretation of the data, current strategies implemented to reduce unhealthy levels of surface ozone should focus more on reducing NO(x) emissions, except in some downtown areas which have historically benefited from reductions in VOC emissions.

Duncan, Bryan N.; Yoshida, Yasuko; Sillman, Sanford; Retscher, Christian; Pickering, Kenneth E.; Martin, Randall V.; Celarier, Edward A.

2009-01-01

239

Simulated changes in biogenic VOC emissions and ozone formation from habitat expansion of Acer Rubrum (red maple)  

NASA Astrophysics Data System (ADS)

A new vegetation trend is emerging in northeastern forests of the United States, characterized by an expansion of red maple at the expense of oak. This has changed emissions of biogenic volatile organic compounds (BVOCs), primarily isoprene and monoterpenes. Oaks strongly emit isoprene while red maple emits a negligible amount. This species shift may impact nearby urban centers because the interaction of isoprene with anthropogenic nitrogen oxides can lead to tropospheric ozone formation and monoterpenes can lead to the formation of particulate matter. In this study the Global Biosphere Emissions and Interactions System was used to estimate the spatial changes in BVOC emission fluxes resulting from a shift in forest composition between oak and maple. A 70% reduction in isoprene emissions occurred when oak was replaced with maple. Ozone simulations with a chemical box model at two rural and two urban sites showed modest reductions in ozone concentrations of up to 5-6 ppb resulting from a transition from oak to red maple, thus suggesting that the observed change in forest composition may benefit urban air quality. This study illustrates the importance of monitoring and representing changes in forest composition and the impacts to human health indirectly through changes in BVOCs.

Drewniak, Beth A.; Snyder, Peter K.; Steiner, Allison L.; Twine, Tracy E.; Wuebbles, Donald J.

2014-01-01

240

DEVELOPMENT OF LASER-BASED SENSORS FOR VOC/NOX AND METALS EMISSIONS MONITORING, CP 1060-97  

EPA Science Inventory

This project addresses the growing Department of Defense (DoD) and Department of Energy (DOE) needs to monitor air emissions in order to comply with more stringent regulatory pressures, such as the Clean Air Act Amendment (CAAA). Specifically, we are focused on the development of...

241

Microscopic fungi as significant sesquiterpene emission sources  

NASA Astrophysics Data System (ADS)

Among the volatile organic compounds emitted by vegetation, isoprene, monoterpenes, sesquiterpenes, and their derivatives are thought to contribute to secondary organic aerosol formation. Although it is well known that microscopic fungi globally turn over vast amount of carbon by decomposing the organic matter in the soil, vegetation is considered as the exclusive source of biogenic secondary organic aerosol precursors in various atmospheric models. Secondary fungal metabolites including sesquiterpenes have been recognized as characteristic volatile organic compounds emitted by fungi. In the present study, we investigated the rates of sesquiterpene emission of microscopic fungi to establish their potential significance compared to those from vegetation. To sample the headspace of the pure culture of some common fungi, we used an aseptic flow-through apparatus designed for solid phase microextraction in our laboratory. The identified sesquiterpenes in the headspace extracts were quantified for eight strains of microscopic fungi belonging to four different genera. Our results showed that microscopic fungi emit a considerable amount of sesquiterpenes. Based on our first estimations microscopic fungi may be considered as potentially significant sesquiterpene emission sources whose contribution to secondary organic aerosol formation may be comparable to that of vegetation.

HorváTh, Eszter; Hoffer, AndráS.; Seb?K, Flóra; Dobolyi, Csaba; Szoboszlay, SáNdor; Kriszt, BaláZs; GelencséR, AndráS.

2011-08-01

242

Source gases: Concentrations, emissions, and trends  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

243

Comparison of seasonal phenol and p-cresol emissions from ground-level area sources in a dairy operation in central Texas.  

PubMed

Although there are more than 200 odor-causing volatile organic compounds (VOCs), phenol and p-cresol are two prominent odor-causing VOCs found downwind from concentrated animal feeding operations (CAFOs). The VOC emissions from cattle and dairy production are difficult to quantify accurately because of their low concentrations, spatial variability, and limitations of available instruments. To quantify VOCs, a protocol following US. Environmental Protection Agency (EPA) Method TO-14A has been established based on the isolation flux chamber method and a portable gas chromatograph (GC) coupled with a purge-and-trap system. The general objective of this research was to quantify phenol and p-cresol emission rates (ERs) from different ground-level area sources (GLASs) in a free-stall dairy during summer and winter seasons using this protocol. Two-week-long sampling campaigns were conducted in a dairy operation in central Texas. Twenty-nine air samples were collected during winter and 37 samples were collected during summer from six specifically delineated GLASs (barn, loafing pen, lagoon, settling basin, silage pile, and walkway) at the free-stall dairy. Thirteen VOCs were identified during the sampling period and the GC was calibrated for phenol and p-cresol, the primary odorous VOCs identified. The overall calculated ERs for phenol and p-cresol were 2656 +/- 728 and 763 +/- 212 mg hd(-1) day(-1), respectively, during winter. Overall phenol and p-cresol ERs were calculated to be 1183 +/- 361 and 551 +/- 214 mg hd(-1) day(-1), respectively, during summer. In general, overall phenol and p-cresol ERs during winter were about 2.3 and 1.4 times, respectively, higher than those during summer. PMID:22616280

Borhan, M S; Capareda, S; Mukhtar, S; Faulkner, W B; McGee, R; Parnell, C B

2012-04-01

244

Chemical loss of volatile organic compounds and its impact on the source analysis through a two-year continuous measurement  

NASA Astrophysics Data System (ADS)

Chemical loss of volatile organic compounds (VOCs) is more important than the observed VOCs, which is the real actor of the chemical process in the atmosphere. The chemical loss of VOCs might impact on the identification of VOCs sources in ambient. For this reason, VOCs with 56 species were continuously measured in the urban area of Shanghai from 2009 to 2010, and based on the measurement the chemical loss of VOCs was calculated. According to the result, the initial VOCs in Shanghai urban was (34.8 ± 20.7) ppbv, higher than the observed one by ˜35%, including alkanes (˜38%), aromatics (˜36%), alkenes (˜17%), and acetylene (˜8%). The chemical reactivity of VOCs would be underestimated by ˜60% if the chemical loss were ignored. The chemical loss of VOCs showed a good agreement with Ox (O3 + NO2). C7-C8 aromatics and C3-C5 alkenes contributed ˜60% of consumed VOCs. Seven sources were identified and quantified from positive matrix factorization (PMF) analysis. Vehicular emissions were the largest anthropogenic source of VOCs in Shanghai urban, accounting for 27.6% of VOCs, followed by solvent usage (19.4%), chemical industry (13.2%), petrochemical industry (9.1%), and coal burning (˜5%). The contribution of biogenic emissions to total VOCs was 5.8%. Besides the five local anthropogenic sources and one biogenic source, the regional transportation was identified as one important source, contributing about 20% of VOCs in Shanghai urban. Sources apportionment results from PMF analysis based on the initial VOCs showed some differences from those based on observed data and might be more appropriate to be applied into the formulation of air pollution control measures.

Wang, H. L.; Chen, C. H.; Wang, Q.; Huang, C.; Su, L. Y.; Huang, H. Y.; Lou, S. R.; Zhou, M.; Li, L.; Qiao, L. P.; Wang, Y. H.

2013-12-01

245

Source identification of benzene emissions in Texas City using an adjoint neighborhood scale transport model  

NASA Astrophysics Data System (ADS)

During the "Formaldehyde and Olefins from Large Industrial Sources" (FLAIR) study in 2009, the Aerodyne Research Inc. (ARI) mobile laboratory performed real-time in situ measurements of VOCs, NOx and HCHO in Texas City, TX on May 7, 2009 from 11 am to 3 pm. This high resolution dataset collected in a predominantly industrial area provides an ideal test bed for advanced source attribution. Our goal was to identify and quantify emission sources within the largest facility in Texas City most likely responsible for measured benzene concentrations. For this purpose, fine horizontal resolution (200 m x 200 m) 4D variational (4Dvar) inverse modeling was performed by running the HARC air quality transport model in adjoint mode based on ambient concentrations measured by the mobile laboratory. The simulations were conducted with a horizontal domain size of 4 km x 4 km for a four-hour period (11 am to 3 pm). Potential emission unit locations within the facility were specified using a high spatial resolution digital model of the largest industrial complex in the area. The HARC model was used to infer benzene emission rates from all potential source locations that would account for the benzene concentrations measured by the Aerodyne mobile laboratory in the vicinity of the facility. A Positive Matrix Factorization receptor model was also applied to the concentrations of other compounds measured by the mobile lab to support the source attribution by the inverse model. Although previous studies attributed measured benzene concentrations during the same time period to a cooling tower unit at the industrial complex, this study found that some of the flare units in the facility were also associated with the elevated benzene concentrations. The emissions of some of these flare units were found to be greater than reported in emission inventories, by up to two orders of magnitude.

Guven, B.; Olaguer, E. P.; Herndon, S. C.; Kolb, C. E.; Cuclis, A.

2012-12-01

246

PAVED ROAD PARTICULATE EMISSIONS: SOURCE CATEGORY REPORT  

EPA Science Inventory

The report gives results of extensive field tests to develop emission factors for particulate emissions generated by traffic entrainment of paved road surface particulate matter. Using roadway surface silt loading as the basis, predictive emission factor equations for each partic...

247

Seasonal and diurnal variations of volatile organic compounds (VOCs) in the atmosphere of Hong Kong  

Microsoft Academic Search

Ambient VOCs samples were collected at three locations (PolyU campus (PU), Kwun Tong (KT), Hok Tsui (HT)) in Hong Kong during the periods of November 2000–February 2001 and June 2001–August 2001. Also the concentrations of VOCs in Cross Harbor tunnel in Hong Kong were obtained in order to determine the vehicular sources of VOCs. Toluene was the most abundant VOC

K. F Ho; S. C Lee; H Guo; W. Y Tsai

2004-01-01

248

Characteristics of atmospheric carbonyls and VOCs in Forest Park in South China.  

PubMed

The diurnal variation of atmospheric carbonyls and VOCs in a forest in south China were studied in summer 2004. Twenty kinds of carbonyls and eight kinds of VOCs were identified and quantified. Formaldehyde and acetaldehyde were the two most abundant carbonyls, while the most abundant VOCs were isoprene, followed by o-xylene. Most C(3)-C(10) carbonyls had higher concentrations from 09:00 to 15:00, and their levels were lower during night-time and often reached the lowest in early morning. Formaldehyde and acetaldehyde, however, showed two high levels in their diurnal patterns partly due to their different sources and sinks. The VOCs had different diurnal patterns compared to most carbonyls. The highest concentrations were observed from 03:00 to 06:00 for 1-butene, from 06:00 to 12:00 for isoprene, and from 12:00 to 15:00 for alpha-pinene. The highest levels for aromatic hydrocarbons occurred during midnight and the lowest in late afternoon. According to the study, emissions from vegetation and photo-oxidation of gas-phase hydrocarbons were the main sources for some carbonyls and VOCs in this region. Other compounds, such as formaldehyde, acetaldehyde and BTEX, showed anthropogenic sources. PMID:17564801

Yu, Yingxin; Wen, Sheng; Lü, Huixiong; Feng, Yanli; Wang, Xinming; Sheng, Guoying; Fu, Jiamo

2008-02-01

249

Location of acoustic emission sources generated by air flow  

Microsoft Academic Search

The location of continuous acoustic emission sources is a difficult problem of non-destructive testing. This article describes one-dimensional location of continuous acoustic emission sources by using an intelligent locator. The intelligent locator solves a location problem based on learning from examples. To verify whether continuous acoustic emission caused by leakage air flow can be located accurately by the intelligent locator,

Tadej Kosel; Igor Grabec; Peter Muži?

2000-01-01

250

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

NASA Astrophysics Data System (ADS)

Mobile sources produce a significant fraction of the total anthropogenic emissions burden in large cities and have harmful effects on air quality at multiple spatial scales. Mobile emissions are intrinsically difficult to estimate due to the large number of parameters affecting the emissions variability within and across vehicles types. The MCMA-2003 Campaign in Mexico City has showed the utility of using a mobile laboratory to sample and characterize specific classes of motor vehicles to better quantify their emissions characteristics as a function of their driving cycles. The technique clearly identifies "high emitter" vehicles via individual exhaust plumes, and also provides fleet average emission rates. We have applied this technique to Mexicali during the Border Ozone Reduction and Air Quality Improvement Program (BORAQIP) for the Mexicali-Imperial Valley in 2005. We analyze the variability of measured emission ratios for emitted NOx, CO, specific VOCs, NH3, and some primary fine particle components and properties by deploying a mobile laboratory in roadside stationary sampling, chase and fleet average operational sampling modes. The measurements reflect various driving modes characteristic of the urban fleets. The observed variability for all measured gases and particle emission ratios is greater for the chase and roadside stationary sampling than for fleet average measurements. The fleet average sampling mode captured the effects of traffic conditions on the measured on-road emission ratios, allowing the use of fuel-based emission ratios to assess the validity of traditional "bottom-up" emissions inventories. Using the measured on-road emission ratios, we estimate CO and NOx mobile emissions of 175±62 and 10.4±1.3 metric tons/day, respectively, for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road emissions data from Mexico City indicated that fleet average NO emission ratios were around 20% higher in Mexicali than in Mexico City whereas HCHO and NH3 emission ratios were higher by a factor of 2 in Mexico City than in Mexicali. Acetaldehyde emission ratios did not differ significantly whereas selected aromatics VOCs emissions were similar or smaller in Mexicali. Nitrogen oxides emissions for on-road heavy-duty diesel truck (HDDT) were measured near Austin, Texas, as well as in both Mexican cities, with NOy emission ratios in Austin < Mexico City < Mexicali.

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

2009-01-01

251

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

NASA Astrophysics Data System (ADS)

Mobile sources produce a significant fraction of the total anthropogenic emissions burden in large cities and have harmful effects on air quality at multiple spatial scales. Mobile emissions are intrinsically difficult to estimate due to the large number of parameters affecting the emissions variability within and across vehicles types. The MCMA-2003 Campaign in Mexico City has showed the utility of using a mobile laboratory to sample and characterize specific classes of motor vehicles to better quantify their emissions characteristics as a function of their driving cycles. The technique clearly identifies "high emitter" vehicles via individual exhaust plumes, and also provides fleet average emission rates. We have applied this technique to Mexicali during the Border Ozone Reduction and Air Quality Improvement Program for the Mexicali-Imperial Valley in 2005. In this paper we analyze the variability of measured emission ratios for emitted NOx, CO, specific VOCs, NH3, and some primary fine particle components and properties obtained during the Border Ozone Reduction and Air Quality Improvement Program for the Mexicali-Imperial Valley in 2005 by deploying a mobile laboratory in roadside stationary sampling, chase and fleet average operational sampling modes. The measurements reflect various driving modes characteristic of the urban fleets. The observed variability for all measured gases and particle emission ratios is greater for the chase and roadside stationary sampling than for fleet average measurements. The fleet average sampling mode captured the effects of traffic conditions on the measured on-road emission ratios, allowing the use of fuel-based emission ratios to assess the validity of traditional "bottom-up" emissions inventories. Using the measured on-road emission ratios, we estimate CO and NOx mobile emissions of 175±62 and 10.4±1.3 metric tons/day, respectively, for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road emissions data from Mexico City indicated that fleet average NO emission ratios were around 20% higher in Mexicali than in Mexico City whereas HCHO and NH3 emission ratios were higher by a factor of 2 in Mexico City than in Mexicali. Acetaldehyde emission ratios did not differ significantly whereas selected aromatics VOCs emissions were similar or smaller in Mexicali. On-road heavy-duty diesel truck (HDDT) nitrogen oxides emissions were measured near Austin, Texas, as well as in both Mexican cities, with NOy emission ratios in Austin < Mexico City < Mexicali.

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

2008-04-01

252

IDENTIFICATION AND CHARACTERIZATION OF MISSING AND UNACCOUNTED FOR AREA SOURCE CATEGORIES  

EPA Science Inventory

The report identifies and characterizes missing or unaccounted for area source categories. Area source emissions of particulate matter (TSP), sulfur dioxide (SO2), oxides of nitrogen (NOx), reactive volatile organic compounds (VOCs), and carbon monoxide (CO) are estimated annuall...

253

Unspeciated Organic Emissions From Combustion Sources And Their Influence On The Secondary Organic Aerosol Budget In The United States  

NASA Astrophysics Data System (ADS)

Combustion sources are a major source of organic emissions and therefore a potentially important source for secondary organic aerosol (SOA) formation in the atmosphere. Although speciated organic emissions from combustion sources are considered in models to form SOA, a large fraction of the organics are unspeciated. In this work, we analyze data from numerous smog chamber experiments, which photo-oxidized dilute emissions from different combustion sources (on-road gasoline vehicles, aircraft, on-road diesel vehicles, wood burning and open biomass burning), to determine the contribution that unspeciated emissions make to SOA formation. An SOA model based on speciated organics is able to explain, on average, 8-31% of the SOA measured in the experiments. We hypothesize that the remainder results from the gas-phase oxidation of unspeciated emissions, which account on average for 25-75% of the non-methane organic gas (NMOG) emissions. Using the SOA data, we develop, for the first time, source-specific parameterizations to model SOA from unspeciated emissions; all sources seem to have median SOA yields similar to large n-alkanes (C12+). To assess the influence of unspeciated emissions on SOA formation regionally, we use the parameterization to predict SOA production in the United States. Using emissions data collected during the smog chamber experiments and data available in literature, we build a gross inventory for unspeciated emissions in the United States. We discover that unspeciated organics might be included in the current generation of SOA models but misallocated in terms of its SOA potential. The top six combustion sources (on- and off-road gasoline, on- and off-road diesel, open biomass and wood burning) emit 2.61 Tg yr-1 of unspeciated emissions (20% of US anthropogenic VOC emissions from combustion sources) and are estimated to form a minimum of 0.68 Tg yr-1 of SOA; the estimate is a third of the biogenic SOA produced in the US. We predict that accounting for SOA from unspeciated emissions will double modeled SOA formation from anthropogenic combustion sources. Primary organic aerosol (POA) emission factors and secondary organic aerosol (SOA) box-plots for five source categories. The colored bars on the right show the median range for the entire data.

Jathar, S.; Gordon, T.; Hennigan, C. J.; Pye, H. O.; Donahue, N. M.; Adams, P. J.; Robinson, A. L.

2012-12-01

254

VOCs monitoring system simulation and design  

NASA Astrophysics Data System (ADS)

The designed and simulated system will be used in the tanning industry, for Volatile Organic Compound (VOC) measurements. In this industry, about 90% of the solvent contained in the emulsions evaporates during its application, giving rise to VOC, which are at the same time hazardous atmospheric pollutants and one of the sources of ground level photochemical ozone formation. It results that a monitoring system is necessary in a leather finishing process, in order to detect hazardous VOC concentration and conducting process in order of VOC concentration diminishing. The paper presents the design of a VOC monitoring system, which includes sensors for VOCs and temperature, the conditioning circuitry for these sensors, the suction system of the gas in the hood, the data acquisition and the computing system and graphic interface. The used sensor in the detection system is a semiconductor sensor, produced by Figaro Engineering Inc., characterized by a short response time, high sensitivity at almost all VOC substances. The design of the conditioning circuitry and data acquisition is done in order to compensate the sensor response variation with temperature and to maintain the low response time of the sensor. The temperature compensation is obtained by using a thermistor circuitry, and the compensation is done within the software design. A Mitsubishi PLC is used to receive the output signals of the circuits including the sensor and of the thermistor, respectively. The acquisition and computing system is done using Mitsubishi ALPHA 2 controller and a graphical terminal, GOT 1000.

Caldararu, Florin; Vasile, Alexandru; Vatra, Cosmin

2010-09-01

255

Acoustic emission point source locations on thin spherical shell  

SciTech Connect

A point source of acoustic emission on a thin spherical shell is defined in spherical and Cartesian coordinates. A required number of acoustic sensors and their locations are postulated for a unique determination of an acoustic emission point source location. Spherical coordinates of an acoustic emission point source are computed using acoustic sensors' measured channel time-differences, radius, and sound propagation velocity in a thin spherical shell.

Burenko, O.; Whittaker, J.

1987-01-01

256

NONFERROUS INDUSTRY PARTICULATE EMISSIONS: SOURCE CATEGORY REPORT  

EPA Science Inventory

The report gives results of the development of particulate emission factors based on cutoff size for inhalable particles for the nonferrous industry. After a review of available information characterizing particulate emissions from nonferrous plants, the data were summarized and ...

257

SOURCES OF ORGANIC AEROSOL: SEMIVOLATILE EMISSIONS AND PHOTOCHEMICAL AGING  

EPA Science Inventory

The proposed research integrates emissions testing, smog chamber experiments, and regional chemical transport models (CTMs) to investigate the sources of organic aerosol in urban and regional environments. ...

258

Source Emissions in Multipollutant Air Quality Management  

Microsoft Academic Search

\\u000a This chapter discusses emissions inventories and emission control technologies in the context of a risk-based, results-oriented\\u000a multipollutant air quality management program. As contemporary emission control technologies often achieve reductions in more\\u000a than one pollutant, the chapter reviews major emissions reduction in North America as examples of multipollutant reduction\\u000a strategies for both criteria pollutants and air toxics. The chapter then comments

C. Andrew Miller

259

VOC flux measurements using a novel Relaxed Eddy Accumulation GC-FID system in urban Houston, Texas  

Microsoft Academic Search

Houston experiences higher ozone production rates than most other major cities in the US, which is related to high anthropogenic VOC emissions from both area\\/mobile sources (car traffic) and a large number of petrochemical facilities. The EPA forecasts that Houston is likely to still violate the new 8-h NAAQS in 2020. To monitor neighborhood scale pollutant fluxes, we established a

G. Schade; I. Boedeker

2008-01-01

260

Biogenic volatile emissions from the soil.  

PubMed

Volatile compounds are usually associated with an appearance/presence in the atmosphere. Recent advances, however, indicated that the soil is a huge reservoir and source of biogenic volatile organic compounds (bVOCs), which are formed from decomposing litter and dead organic material or are synthesized by underground living organism or organs and tissues of plants. This review summarizes the scarce available data on the exchange of VOCs between soil and atmosphere and the features of the soil and particle structure allowing diffusion of volatiles in the soil, which is the prerequisite for biological VOC-based interactions. In fact, soil may function either as a sink or as a source of bVOCs. Soil VOC emissions to the atmosphere are often 1-2 (0-3) orders of magnitude lower than those from aboveground vegetation. Microorganisms and the plant root system are the major sources for bVOCs. The current methodology to detect belowground volatiles is described as well as the metabolic capabilities resulting in the wealth of microbial and root VOC emissions. Furthermore, VOC profiles are discussed as non-destructive fingerprints for the detection of organisms. In the last chapter, belowground volatile-based bi- and multi-trophic interactions between microorganisms, plants and invertebrates in the soil are discussed. PMID:24689847

Peñuelas, J; Asensio, D; Tholl, D; Wenke, K; Rosenkranz, M; Piechulla, B; Schnitzler, J P

2014-08-01

261

Asbestos Emissions from Baghouse Controlled Sources  

Microsoft Academic Search

There is virtually no information published on the absolute efficiency of baghouses in reducing the emissions of fine particles of asbestos. This lack of information is unfortunate because serious occupational health problems may result from the common practice of recirculating air to conserve energy. Emission testing has been conducted at five asbestos processing plants where the emissions are controlled by

COLIN F. HARWOOD; DAVID K. OESTREICH; PAUL SIEBERT; JOHN D. STOCKHAM

1975-01-01

262

[Preliminary study concerning emissions of the volatile organic compounds from cooking oils].  

PubMed

Cooking oil fume is one of the important sources of atmospheric volatile organic compounds (VOCs), which are the key precursors of ozone and secondary organic aerosols in air. In this study, the production of cooking oil fume was simulated by heating typical pure vegetable oils (peanut oil, sunflower oil, soybean oil, olive oil and blend oil) at different temperatures in beakers to investigate the VOCs emission characteristics. The emitted VOCs were sampled with a Tenax adsorption tube and analyzed using GC-MS after thermal desorption. The results showed that the emission of VOCs increased with the increase of the heating temperature for all the investigated cooking oils, and at a given temperature, the blend oil emitted the lowest amount of VOCs. The VOCs emission intensity at different heating temperatures fitted well with binomial equations and ranged from 1.6-11.1 mg x (kg x min)(-1). PMID:23243847

He, Wan-Qing; Tian, Gang; Nie, Lei; Qu, Song; Li, Jing; Wang, Min-Yan

2012-09-01

263

SOURCES, EMISSION AND EXPOSURE TO TRICHLOROETHYLENE (TCE) AND RELATED CHEMICALS  

EPA Science Inventory

This report documents the sources, emission, environmental fate and exposures for TCE, some of its metabolites, and some other chemicals known to produce identical metabolites. The major findings for TCE are: The primary sources releasing TCE to the environment ...

264

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

EPA Science Inventory

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

265

RESEARCH AREA -- MOBILE SOURCE EMISSIONS (EMISSIONS CHARACTERIZATION AND PREVENTION BRANCH, APPCD, NRMRL)  

EPA Science Inventory

The objective of this program is to characterize mobile source emissions which are one of the largest sources of tropospheric ozone precursor emissions (CO, NOx, and volotile organic compounds) in the U.S. The research objective of the Emissions Characterization and Prevention Br...

266

Diurnal and seasonal variability of gasoline-related volatile organic compound emissions in Riverside, California.  

PubMed

On- and off-road mobile sources are the dominant contributors to urban anthropogenic volatile organic compound (AVOC) emissions. Analyses of gasoline samples from California for both summer and winter indicate significant differences in liquid fuel and vapor chemical composition due to intentional seasonal adjustments. Ambient concentrations of 55 VOCs were measured via in situ gas chromatography in the 2005 Study of Organic Aerosols at Riverside (SOAR) during both summer and fall. A chemical mass balance analysis was used to differentiate vapor pressure-driven VOC emissions from other motor vehicle-related emissions such as tailpipe exhaust. Overall, fuel vapor emissions accounted for 31 +/- 2% of gasoline-related VOC in Riverside; California's emission factor model similarly estimates 31% of gasoline-related VOC emissions are fuel vapor. The diurnal pattern of vapor pressure-driven VOC source contributions is relatively stable around 10 microg/m3, while whole gasoline (i.e., tailpipe) contributions peak at approximately 60 microg/m3 during the morning commute. There is no peak in whole gasoline source contributions during the afternoon, due to rapid dilution associated with high mixing heights and wind speeds in the Riverside area. The relationship between estimated gasoline-related VOC and observed carbon monoxide concentrations in this study is similar to California's 2005 emission inventory; we calculated a VOC to CO mass ratio of 0.086 +/- 0.006 (95% CI) compared to 0.097 in the emission inventory for all gasoline-related sources. PMID:19603630

Gentner, Drew R; Harley, Robert A; Miller, Angela M; Goldstein, Allen H

2009-06-15

267

An Emission Inventory of Nonpoint Oil and Gas Emissions Sources in the Western Region  

Microsoft Academic Search

As part of an effort undertaken by the Western Regional Air Partnership (WRAP) to consolidate and improve on the 2002 state and tribal emission inventories, ENVIRON developed an emission inventory of non-point emission sources associated with the production of oil and gas. This inventory focused on emissions of nitrous oxides from compressor engines, drill rig engines and coalbed methane pump

James Russell; Alison Pollack; Greg Yarwood

268

Cryogenic condensation puts a chill on VOCs  

SciTech Connect

Any industry that uses or handles solvents as part of the manufacturing process--production, storage or recycling--will at some point release volatile organic compounds (VOCs) into the atmosphere. It is difficult for any company to select an abatement technique that is both affordable and will meet the requirements of the specific VOC emission regulations. The selection process can be complicated because such a wide range of VOC control technologies is available. While many of these VOC control technologies satisfy regulatory requirements, the challenge is to find a technology that is not only efficient but also cost effective. One such technique uses low-temperature condensation for abatement and recovery of VOCs emitted during the manufacturing process. The low-temperature refrigeration for the system is provided by the cooling value in liquid nitrogen. Most chemical processing industries use significant quantities of liquid nitrogen in applications such as inerting, blanketing and purging; it can be reused onsite, therefore, and no additional nitrogen need be purchased. As a result, VOC control is achieved with low operating costs.

Zeiss, R.F.; Ibbetson, C.

1997-09-01

269

Carbonyl Emissions from Vehicular Exhausts Sources in Hong Kong  

Microsoft Academic Search

Vehicular emission (VE) is one of the important anthropogenic sources for airborne carbonyls in urban area. Six types of VE-dominated samples were collected at representative locations in Hong Kong where polluted by a particular fueled type of vehicles, including (i) a gas refilling taxis station (liquefied petroleum gas [LPG] emission); (ii) a light duty passenger car park (gasoline emission); (iii)

Steven Sai Hang Ho; Kin Fai Ho; Shun Cheng Lee; Yan Cheng; Jian Zhen Yu; Ka Man Lam; Carrie Feng; Yu Huang

2011-01-01

270

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

271

RESEARCH AREA -- STATIONARY SOURCE EMISSIONS CHARACTERIZATION (EMISSIONS CHARACTERIZATION AND PREVENTION BRANCH, APPCD, NRMRL)  

EPA Science Inventory

Research and development of models to estimate emissions from dynamic oil and gas industry and commercial sources is the objective of this program. The Emission Characterization and Prevention Branch, the American Petroleum Institute, and the Gas Research Institute have jointly ...

272

Dry Sources of Plume Emissions on Enceladus  

NASA Astrophysics Data System (ADS)

Salt-bearing icy particles [1], inorganic gases [2] and organic species [2,3] emitted from Enceladus could originate in the heterogeneous icy shell that captured oceanic water and primordial solids earlier in history. A major trapping could have occurred during sinking of a dense (1.6 g/cm3) primordial rock-ice crust [4] into an early salt-, gas- and organic-bearing ocean [5]. The lack of spectral and geological signs for rocky components at the surface is consistent with the submergence of primordial crust that has not been affected by initial water-rock differentiation. The sinking could have been triggered by impacts and/or volume changes in the interior. A rapid submergence could have caused vigorous boiling and freezing of oceanic water that appeared at the surface. The low temperature of submerged crust, and cooling of surface waters may have limited major melting of sunken rock-ice blocks. Some primary spices (e.g. HCN [2]), if released from sunken rock-ice debris, could have been re-captured in ice, which limited their chemical interactions. After formation of a thin icy shell, diking events and impacts caused further trapping of salty oceanic water in multiple disrupted areas, as occurred on Europa. Condensed and soluble organic compounds, and at least some CO2, N2, CH4 and light hydrocarbons released via oceanic degassing were trapped as well. The concentration of salts in rapidly frozen oceanic water reflected oceanic composition, and the salt/water ratio in Na-rich E-ring particles [1] may represent salinity of the early ocean. In fact, the salinity inferred from the composition of salt-rich particles (4-20 g/kg H2O [1]) and salt composition matches models for the early ocean [5]. The Na-poor E-ring particles [1] may originate from a middle part of the icy shell that formed through slow downward freezing and expelling impurities into solution. The dominance of Na-poor E-ring icy grains (~93%, [1]) implies a low volume of salty ice that represents rapidly frozen early oceanic water. A lack of highly saline particles in E ring that are expected to form due to significant evaporation of an aqueous reservoir also argues for dry sources. The E-ring grains [1,3] may represent neither thick salt deposits at the core-ice boundary nor brines that may exist at that boundary today [5]. A low upper limit for atomic Na content at Enceladus [6] is consistent with Na emission in salt particles from dry sources. A low (far from eutectic) NH3/H2O ratio in plumes [2] implies dry sources as well. If present, primary species (e.g. NH3, HCN) in plums [2] and Mg silicates in E-ring particles [3] could originate from unmelted fragments of sunken primordial crust that have been incorporated into the formed icy shell. The structural heterogeneity of current icy shell may account for the chemical diversity of gases [2] and solids [1,3] emitted from Enceladus. Refs.: [1] Portberg F. et al. (2009) Nature 459, 1098-1101. [2] Waite J. et al. et al. (2009) Nature 460, 487-490. [3] Postberg F. et al. (2008) Icarus 193, 438-454. [4] Schubert G. et al. (2007) Icarus 188, 335-345. [5] Zolotov M. (2007) GRL 34, L23203. [6] Schneider N. et al. (2009) Nature 459, 1098-1101.

Zolotov, M. Y.

2009-12-01

273

Application of OMI Observations to a Space-Based Indicator of NOx and VOC Controls on Surface Ozone Formation  

NASA Technical Reports Server (NTRS)

We investigated variations in the relative sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NOx) as inferred from the ratio of the tropospheric columns of formaldehyde to nitrogen dioxide (the "Ratio") from the Aura Ozone Monitoring Instrument (OMI). Our modeling study suggests that ozone formation decreases with reductions in VOCs at Ratios less than 1 and NOx at Ratios greater than 2; both NOx and VOC reductions may decrease ozone formation for Ratios between 1 and 2. Using this criteria. the OMI data indicate that ozone formation became: 1. more sensitive to NOx over most of the United States from 2005 to 2007 because of the substantial decrease in NOx emissions, primarily from stationary sources, and the concomitant decrease in the tropospheric column of NO2. and 2. more sensitive to NOx with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. In cities with relatively low isoprene emissions (e.g .. Chicago). the data clearly indicate that ozone formation became more sensitive to NOx from 2005 to 2007. In cities with relatively high isoprene emissions (e.g ., Atlanta), we found that the increase in the Ratio due to decreasing NOx emissions was not obvious as this signal was convolved with variations in the Ratio associated with the temperature dependence of isoprene emissions and, consequently, the formaldehyde concentration.

Duncan, Bryan N.; Yoshida, Yasuko; Olson, Jennifer R.; Sillman, Sanford; Martin, Randall V.; Lamsal, Lok; Hu, Yongtao; Pickering, Kenneth E.; Retscher, Christian; Allen, Dale J.; Crawford, James H.

2010-01-01

274

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 3. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-1  

EPA Science Inventory

Radian Corporation is conducting a testing program for the EPA (Contract No. 68-02-3171, Work Assignment 50) to document the performance of catalytic incinerators applied to industrial processes for volatile organic compound (VOC) control. Performance data collected at each test ...

275

Release of VOCs and particles during use of nanofilm spray products.  

PubMed

Here, we present emission data on VOCs and particles emitted during simulated use of four commercial nanofilm spray products (NFPs) used for making easy-to-clean or self-cleaning surfaces on floors, ceramic tiles, and windows. The aim was to characterize the emitted VOCs and to provide specific source strength data for VOCs and particles released to the airduring use of the products. Containers with NFP were mounted on a spray-stand inside a closed stainless steel chamber with no air exchange. NFPs were sprayed in amounts corresponding to 1 m2 surface toward a target plate at a distance of 35 cm. Released VOCs were measured by a combination of air sampling on Tenax TA adsorbent followed by thermal desorption GC/MS and GC/FID analysis and real time measurements using a miniature membrane inlet mass spectrometer. Particles were measured using a fast mobility particle sizer and an aerosol particle sizer. A number of VOCs were identified, including small alcohols, ketones and ethers, chlorinated acetones, a perfluorinated silane, limonene, and cyclic siloxanes. The number of generated particles was on the order of 3 x 10(8) to 2 x 10(10) particles/m3 per g sprayed NFP and were dominated by nanosize particles. PMID:19921900

Nørgaard, Asger W; Jensen, Keld A; Janfelt, Christian; Lauritsen, Frants R; Clausen, Per A; Wolkoff, Peder

2009-10-15

276

Exposure to volatile organic compounds for individuals with occupations associated with potential exposure to motor vehicle exhaust and\\/or gasoline vapor emissions  

Microsoft Academic Search

Workers who work near volatile organic compounds (VOCs) source(s), motor vehicle exhausts and\\/or gasoline vapor emissions, are suspected to be exposed to highly-elevated VOC levels during their work-time. This study confirmed this suspicion and evaluated the work-time exposure VOCs for traffic police officers, parking garage attendants, service station attendants, roadside storekeepers and underground storekeepers, by measuring the concentrations of six

Wan-Kuen Jo; Ki-Berm Song

2001-01-01

277

Registration for the Hanford Site: Sources of radioactive emissions  

SciTech Connect

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

Silvia, M.J.

1993-04-01

278

A temporally and spatially resolved validation of emission inventories by measurements of ambient volatile organic compounds in Beijing, China  

NASA Astrophysics Data System (ADS)

Understanding the sources of volatile organic compounds (VOCs) is essential for ground-level ozone and secondary organic aerosol (SOA) abatement measures. We made VOC measurements at 27 sites and online observations at an urban site in Beijing from July 2009 to January 2012. Based on these measurement data, we determined the spatial and temporal distribution of VOCs, estimated their annual emission strengths based on their emission ratios relative to carbon monoxide (CO), and quantified the relative contributions of various sources using the chemical mass balance (CMB) model. These results from ambient measurements were compared with existing emission inventories to evaluate the spatial distribution, species-specific emissions, and source structure of VOCs in Beijing. The measured VOC distributions revealed a hotspot in the southern suburban area of Beijing, whereas current emission inventories suggested that VOC emissions were concentrated in downtown areas. Compared with results derived from ambient measurements, the annual inventoried emissions of oxygenated VOC (OVOC) species and C2-C4 alkanes may be underestimated, while the emissions of styrene and 1,3-butadiene may be overestimated by current inventories. Source apportionment using the CMB model identified vehicular exhaust as the most important VOC source, with the relative contribution of 49%, in good agreement with the 40-51% estimated by emission inventories. The relative contribution of paint and solvent utilization obtained from the CMB model was 14%, significantly lower than the value of 32% reported by one existing inventory. Meanwhile, the relative contribution of liquefied petroleum gas (LPG) usage calculated using the CMB model was 6%, whereas LPG usage contribution was not reported by current emission inventories. These results suggested that VOC emission strengths in southern suburban area of Beijing, annual emissions of C2-C4 alkanes, OVOCs and some alkenes, and the contributions of solvent and paint utilization and LPG usage in current inventories all require significant revisions.

Wang, M.; Shao, M.; Chen, W.; Yuan, B.; Lu, S.; Zhang, Q.; Zeng, L.; Wang, Q.

2014-06-01

279

Diagnostic modeling of PAMS VOC observation.  

PubMed

Although a number of gas-phase chemical mechanisms, such as CBM-IV, RADM2, and SAPRC have been successful in studying gas-phase atmospheric chemical processes, they all used different combinations of lumped organic species to describe the role of organics in gas-phase chemical processes. Photochemical Assessment Monitoring Stations (PAMS) have been in use for over a decade and yet it is not clear how the detailed organic species measured by PAMS compare to the lumped modeled species. By developing a detailed mechanism specifically for the PAMS organics and embedding this diagnostic model within a regional-scale transport and chemistry model, one can then directly compare PAMS observation with regional-scale model simulations. By means of this comparison one can perhaps better evaluate model performance. The Taiwan Air Quality Model (TAQM) was modified by adding a submodel with transport processes and chemical mechanism for interactions of the 56 species observed by PAMS. It is assumed that TAQM can simulate the overall regional-scale environment including time evolution of oxidants and radicals; these results are then used to simulate the evolution of PAMS organics with species-specific source functions, meteorological transport, and chemical interactions. Model simulations of each PAMS organic were compared with PAMS hourly surface measurements. A case study with data collected at three sites in central Taiwan showed that when meteorological simulations were comparable with observations, diurnal patterns of most organics performed well with PAMS data after emissions were corrected. It is found emissions of over half of the PAMS species require correction, some by surprisingly large factors. With such correlation, simulated time evolution of ratios of ethylbenzene/m,p-xylenes and ethane/n-butane showed similar behaviors as shown by observation data. From the results of PAMS organics diurnal variations as well as indicator ratios, one can conclude that PAMS Air Quality Model (PAMS-AQM) has been successfully developed and can be applied to the study of evolution of PAMS organics in regional and urban environments. Further, one finds that an existing VOC emissions estimation procedure heavily dependent on U.S.-data based emissions speciation factors is suspect in application in Taiwan and perhaps in other countries as well. A protocol, using PAMS-AQM for testing consistency between detailed VOC emissions and PAMS observations, has been developed and demonstrated. PMID:20476789

Chen, Sheng-Po; Liu, Tsun-Hsien; Chen, Tu-Fu; Yang, Chang-Feng Ou; Wang, Jia-Lin; Chang, Julius S

2010-06-15

280

Remote measurement of ground source emissivity.  

National Technical Information Service (NTIS)

The remote measurement of the emissivity of ground materials is of tremendous value in their identification and mapping. Traditional techniques use reflected solar radiation for this measurement for wavelengths shorter than 5 micrometers. With the develop...

J. R. Henderson

1995-01-01

281

Location of acoustic emission sources generated by air flow  

PubMed

The location of continuous acoustic emission sources is a difficult problem of non-destructive testing. This article describes one-dimensional location of continuous acoustic emission sources by using an intelligent locator. The intelligent locator solves a location problem based on learning from examples. To verify whether continuous acoustic emission caused by leakage air flow can be located accurately by the intelligent locator, an experiment on a thin aluminum band was performed. Results show that it is possible to determine an accurate location by using a combination of a cross-correlation function with an appropriate bandpass filter. By using this combination, discrete and continuous acoustic emission sources can be located by using discrete acoustic emission sources for locator learning. PMID:10829780

Kosel; Grabec; Muzic

2000-03-01

282

Differences in source emission rates of volatile organic compounds in inner-city residences of New York City and Los Angeles.  

PubMed

The Toxics Exposure Assessment Columbia-Harvard (TEACH) Project characterized personal, indoor, and outdoor concentrations of a suite of volatile organic compounds (VOCs) for high school students living in New York City (NYC) and Los Angeles (LA). This paper presents the analysis of VOC measurements collected indoors and outdoors for 46 students' homes in NYC and for 41 students' homes in LA across two seasons. Dual-sorbent thermal desorption tubes were used for the collection of 15 VOCs and C(18) 2,4-dinitrophenylhydrazine-coated cartridges were used for the collection of seven aldehydes. Air-exchange rates (AERs) were also measured using a perfluorocarbon tracer gas method. The AERs were lower in the winter in both cities, averaging 1 h(-1) in NYC and 1.4 h(-1) in LA, compared with 1.8 h(-1) in NYC in the summer and 2.5 h(-1) in LA in the fall. Higher AERs were generally associated with lower indoor-outdoor ratios with significant differences for the compounds with indoor sources, including chloroform, 1,4-dichlorobenzene, and formaldehyde. Using a mass-balance model to account for AER and other housing parameters, effective source emission rates (SER) were calculated for each compound. Based on I/O ratios and source emission rates, VOCs could be divided into: (1). indoor-source-influenced compounds, (2). those with contributions from both indoor and outdoor sources, and (3). those with mostly outdoor sources. Significant indoor sources were found for the following six compounds (mean emission rates presented): chloroform (0.11 mg/h), 1,4-dichlorobenzene (19 mg/h), formaldehyde (5 mg/h), acetaldehyde (2 mg/h), benzaldehyde (0.6 mg/h), and hexaldehyde (2 mg/h). Although chloroform had variable I/O ratios across seasons, SERs, which accounted for AER, were similar in both cities for both seasons (e.g., LA means 0.12 and 0.11 mg/h in winter and fall, respectively). Formaldehyde had substantially higher indoor emission rates in the summer in NYC compared to winter (3.8 vs. 1.6 mg/h) but lower in the fall in LA compared to winter (4.3 vs. 5.0 mg/h). Uncertainty analysis determined that source strength calculations were not sensitive to measurement error for a subset of homes in LA. PMID:15118751

Sax, Sonja N; Bennett, Deborah H; Chillrud, Steven N; Kinney, Patrick L; Spengler, John D

2004-01-01

283

A LOW COST CATALYTIC FILTER FOR SIMULTANEOUS VOC AND PARTICULATE REMOVAL - PHASE II  

EPA Science Inventory

Emissions of VOC's are subject to control by the EPA both because VOC's are regarded as ozone precursors and because many specific VOC's are hazardous air pollutants (HAP's) under the Clean Air Act Amendments. A number of industries generate offgases with both fine particul...

284

Satellite Remote Sensing of Ozone-NOx-VOC Sensitivity  

NASA Astrophysics Data System (ADS)

We present a novel capability in satellite remote sensing with implications for air pollution control strategy. Uncertainty in the relation between surface ozone and its two main precursors, nitrogen oxides (NOx=NO+NO2) and volatile organic compounds (VOCs) remains a primary obstacle to improving surface air quality. The design of control strategies for surface ozone has been impeded by limited observations of ozone-NOx-VOC sensitivity. We show that the ratio of formaldehyde to tropospheric nitrogen dioxide columns is an indicator of the relative sensitivity of surface ozone to emissions of NOx and VOCs. Space-based observations of the ratio from the GOME satellite instrument reveal that surface ozone is more sensitive to emissions of NOx than of VOCs throughout most of the Northern Hemisphere during summer. Exceptions include Los Angeles and industrial areas of Germany. A seasonal transition occurs in the fall when surface ozone becomes less sensitive to NOx and more sensitive to VOCs.

Martin, R. V.; Fiore, A.; Donkelaar, A. V.

2004-05-01

285

Characterization of emissions from combustion sources: controlled studies  

SciTech Connect

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

Tucker, W.G.

1987-01-01

286

VOC composition of current motor vehicle fuels and vapors, and collinearity analyses for receptor modeling.  

PubMed

The formulation of motor vehicle fuels can alter the magnitude and composition of evaporative and exhaust emissions occurring throughout the fuel cycle. Information regarding the volatile organic compound (VOC) composition of motor fuels other than gasoline is scarce, especially for bioethanol and biodiesel blends. This study examines the liquid and vapor (headspace) composition of four contemporary and commercially available fuels: gasoline (<10% ethanol), E85 (85% ethanol and 15% gasoline), ultra-low sulfur diesel (ULSD), and B20 (20% soy-biodiesel and 80% ULSD). The composition of gasoline and E85 in both neat fuel and headspace vapor was dominated by aromatics and n-heptane. Despite its low gasoline content, E85 vapor contained higher concentrations of several VOCs than those in gasoline vapor, likely due to adjustments in its formulation. Temperature changes produced greater changes in the partial pressures of 17 VOCs in E85 than in gasoline, and large shifts in the VOC composition. B20 and ULSD were dominated by C(9) to C(16)n-alkanes and low levels of the aromatics, and the two fuels had similar headspace vapor composition and concentrations. While the headspace composition predicted using vapor-liquid equilibrium theory was closely correlated to measurements, E85 vapor concentrations were underpredicted. Based on variance decomposition analyses, gasoline and diesel fuels and their vapors VOC were distinct, but B20 and ULSD fuels and vapors were highly collinear. These results can be used to estimate fuel related emissions and exposures, particularly in receptor models that apportion emission sources, and the collinearity analysis suggests that gasoline- and diesel-related emissions can be distinguished. PMID:22154341

Chin, Jo-Yu; Batterman, Stuart A

2012-03-01

287

Intelligent location of simultaneously active acoustic emission sources: Part I  

Microsoft Academic Search

The intelligent acoustic emission (AE) locator is described in Part I while Part II discusses a blind source separation, time delay estimation and location of two simultaneously active continuous AE sources. Location of AE on complicated aircraft frame structures is a difficult problem of non-destructive testing. In this article an intelligent AE source locator is described. The intelligent locator is

Tadej Kosel; Igor Grabec; Franc Kosel

2003-01-01

288

CO line emission observations of bright IRAS sources.  

NASA Astrophysics Data System (ADS)

Observations of CO(1-0) line emission from 27 bright IRAS sources (with fluxes F100?m ? 500 Jy) have been made using the 13.7 m telescope of the Purple Mountain Observatory at the Qinghai Station. The authors found that all the 27 sources are associated with molecular clouds and related to the formation or early evolution of massive stars. Thirteen new CO emission spectra are presented. The properties of CO emission from this kind of sources are also discussed briefly.

Sun, Jin; Sun, Yanchun; Hua, Hai

1998-04-01

289

[Pollution characteristics and health risk assessment of atmospheric VOCs in the downtown area of Guangzhou, China].  

PubMed

The measurements of 31 kinds of VOCs in the ambient air of a site were carried out in the downtown of Guangzhou by online method from November 5, 2009 to November 9, 2009. The ambient level and composition characteristics, temporal variation characteristics, sources identification, and chemical reactivity of VOCs were studied, and the health risk of VOCs in the ambient air in the study area was assessed by using the international recognized health risk assessment method. Results showed that the mean and the range of the mass concentrations of 31 VOCs were 114.51 microg x m(-3) and 29.42-546.06 microg x m(-3), respectively. The mass concentrations of 31 VOCs, and those of alkanes, alkenes, and aromatics all showed a changing trend of higher in the morning and in the evening, and lower at noontime. Vehicular exhaust, gasoline and liquefied petroleum gas evaporates were the main sources of VOCs with the volatilization of paints and solvents being important emission sources. Toluene, trans-2-butene, m/p-xylene, i-butane, and 1,3,5-trimethylbenzene were the key reactive species among the 31 VOCs. Vehicular exhaust and gasoline evaporation were the main sources of VOCs leading to the formation of ozone. Health risk assessment showed that n-hexane, 1,3-butadiene, benzene, toluene, ethylbenzene, m/p-xylene and o-xylene had no appreciable risk of adverse non-cancer health effect on the exposed population, but 1, 3-butadiene and benzene had potential cancer risk. By comparing the corresponding data about health risk assessment of benzene compounds in some cities in China, it is concluded that benzene can impose relatively high cancer risk to the exposed populations in the ambient air of some cities in China. Therefore, strict countermeasures should be taken to further control the pollution of benzene in the ambient air of cities, and it is imperative to start the related studies and develop the atmospheric environmental health criteria and national ambient air quality standard for benzene in China. PMID:24640890

Li, Lei; Li, Hong; Wang, Xue-Zhong; Zhang, Xin-Min; Wen, Chong

2013-12-01

290

78 FR 24990 - Approval and Promulgation of Implementation Plans; Ohio; Volatile Organic Compound Emission...  

Federal Register 2010, 2011, 2012, 2013

...Implementation Plans; Ohio; Volatile Organic Compound Emission Control Measures for...Implementation Plan (SIP), several volatile organic compound (VOC) rules that were submitted...stationary sources, storage of volatile organic liquids, industrial cleaning...

2013-04-29

291

?13C of volatile organic compounds (VOCS) in airborne samples by thermal desorption-gas chromatography-isotope ratio-mass spectrometry (TD-GC-IR-MS)  

NASA Astrophysics Data System (ADS)

This paper is a preliminary investigation into the use of a thermal desorption-gas chromatography-isotope ratio mass spectrometry (TD-GC-IR-MS) method to determine stable carbon isotopic compositions ( ?13C) of low molecular-weight volatile organic compounds (VOCs) in airborne samples (e.g. industrial and car exhaust emissions) as a means of differentiating their sources in the environment. A TD-GC-IR-MS method for obtaining ?13C of VOCs (benzene, toluene, chlorobenzene, ethylbenzene, m-xylene and propylbenzene) in air samples has been optimised, and is proven to be both reproducible and linear. The ?13C of the VOC standards was found to be comparable (within analytical error) to that obtained from direct GC-IR-MS analysis. This novel method of VOC analysis is valuable in environmental and forensic investigations.

Turner, Nicole; Jones, Mark; Grice, Kliti; Dawson, Daniel; Ioppolo-Armanios, Marisa; Fisher, Steven J.

292

User access to the MAP3S source emissions inventory  

SciTech Connect

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

Benkovitz, C M; Evans, V A

1981-03-01

293

METHOD FOR MEASURING CARBON FIBER EMISSIONS FROM STATIONARY SOURCES  

EPA Science Inventory

Carbon fibers are highly conductive, lightweight and of small dimensions. When released as emissions from production, manufacturing, processing and disposal sources they may become airborne and disperse over wide areas. If they settle onto electronic or electrical components they...

294

Instrumentation for Monitoring Specific Particulate Substances in Stationary Source Emissions.  

National Technical Information Service (NTIS)

The report describes the development of an engineering prototype analytical and sampling system capable of monitoring continuously the concentration of beryllium and cadmium in typical stationary source emissions. Data for laboratory tests with radio-freq...

J. V. Pustinger D. A. Shaw P. L. Sherman A. D. Snyder

1973-01-01

295

DEVELOPMENT OF A MONITOR FOR HCN IN MOBILE SOURCE EMISSIONS  

EPA Science Inventory

Three real-time monitors for measurement of HCN concentrations in mobile source emissions have been designed, built, tested, and delivered to the Environmental Protection Agency (EPA). The important design parameters for these identical instruments were determined during the firs...

296

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

Code of Federal Regulations, 2010 CFR

...Emissions sources 1. Sodium chromate production a. Ball mill used to grind chromite ore. b. Dryer used to dry chromite ore. c. Rotary kiln used to roast chromite ore to produce sodium chromate. d. Secondary rotary kiln used to...

2010-07-01

297

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

Code of Federal Regulations, 2010 CFR

...Emissions sources 1. Sodium chromate production a. Ball mill used to grind chromite ore. b. Dryer used to dry chromite ore. c. Rotary kiln used to roast chromite ore to produce sodium chromate. d. Secondary rotary kiln used to...

2009-07-01

298

Boreal forest fire emissions in fresh Canadian smoke plumes: C1-C10 volatile organic compounds (VOCs), CO2, CO, NO2, NO, HCN and CH3CN  

NASA Astrophysics Data System (ADS)

Boreal regions comprise about 17 % of the global land area, and they both affect and are influenced by climate change. To better understand boreal forest fire emissions and plume evolution, 947 whole air samples were collected aboard the NASA DC-8 research aircraft in summer 2008 as part of the ARCTAS-B field mission, and analyzed for 79 non-methane volatile organic compounds (NMVOCs) using gas chromatography. Together with simultaneous measurements of CO2, CO, CH4, CH2O, NO2, NO, HCN and CH3CN, these measurements represent the most comprehensive assessment of trace gas emissions from boreal forest fires to date. Based on 105 air samples collected in fresh Canadian smoke plumes, 57 of the 80 measured NMVOCs (including CH2O) were emitted from the fires, including 45 species that were quantified from boreal forest fires for the first time. After CO2, CO and CH4, the largest emission factors (EFs) for individual species were formaldehyde (2.1 ± 0.2 g kg-1), followed by methanol, NO2, HCN, ethene, ?-pinene, ?-pinene, ethane, benzene, propene, acetone and CH3CN. Globally, we estimate that boreal forest fires release 2.4 ± 0.6 Tg C yr-1 in the form of NMVOCs, with approximately 41 % of the carbon released as C1-C2 NMVOCs and 21 % as pinenes. These are the first reported field measurements of monoterpene emissions from boreal forest fires, and we speculate that the pinenes, which are relatively heavy molecules, were detected in the fire plumes as the result of distillation of stored terpenes as the vegetation is heated. Their inclusion in smoke chemistry models is expected to improve model predictions of secondary organic aerosol (SOA) formation. The fire-averaged EF of dichloromethane or CH2Cl2, (6.9 ± 8.6) × 10-4 g kg-1, was not significantly different from zero and supports recent findings that its global biomass burning source appears to have been overestimated. Similarly, we found no evidence for emissions of chloroform (CHCl3) or methyl chloroform (CH3CCl3) from boreal forest fires. The speciated hydrocarbon measurements presented here show the importance of carbon released by short-chain NMVOCs, the strong contribution of pinene emissions from boreal forest fires, and the wide range of compound classes in the most abundantly emitted NMVOCs, all of which can be used to improve biomass burning inventories in local/global models and reduce uncertainties in model estimates of trace gas emissions and their impact on the atmosphere.

Simpson, I. J.; Akagi, S. K.; Barletta, B.; Blake, N. J.; Choi, Y.; Diskin, G. S.; Fried, A.; Fuelberg, H. E.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Wennberg, P. O.; Wiebring, P.; Wisthaler, A.; Yang, M.; Yokelson, R. J.; Blake, D. R.

2011-07-01

299

Boreal forest fire emissions in fresh Canadian smoke plumes: C1-C10 volatile organic compounds (VOCs), CO2, CO, NO2, NO, HCN and CH3CN  

NASA Astrophysics Data System (ADS)

Boreal regions comprise about 17% of the global land area, and they both affect and are influenced by climate change. To better understand boreal forest fire emissions and plume evolution, 947 whole air samples were collected aboard the NASA DC-8 research aircraft in summer 2008 as part of the ARCTAS-B field mission, and analyzed for 79 non-methane volatile organic compounds (NMVOCs) using gas chromatography. Together with simultaneous measurements of CO2, CO, CH4, CH2O, NO2, NO, HCN and CH3CN, these measurements represent the most comprehensive assessment of trace gas emissions from boreal forest fires to date. Based on 105 air samples collected in fresh Canadian smoke plumes, 57 of the 80 measured NMVOCs (including CH2O) were emitted from the fires, including 45 species that were quantified from boreal forest fires for the first time. After CO2, CO and CH4, the largest emission factors (EFs) for individual species were formaldehyde (2.1 ± 0.2 g kg-1), followed by methanol, NO2, HCN, ethene, ?-pinene, ?-pinene, ethane, benzene, propene, acetone and CH3CN. Globally, we estimate that boreal forest fires release 2.4 ± 0.6 Tg C yr-1 in the form of NMVOCs, with approximately 41% of the carbon released as C1-C2 NMVOCs and 21% as pinenes. These are the first reported field measurements of monoterpene emissions from boreal forest fires, and we speculate that the pinenes, which are relatively heavy molecules, were detected in the fire plumes as the result of distillation of stored terpenes as the vegetation is heated. Their inclusion in smoke chemistry models is expected to improve model predictions of secondary organic aerosol (SOA) formation. The fire-averaged EF of dichloromethane or CH2Cl2, (6.9 ± 8.6) ×10-4 g kg-1, was not significantly different from zero and supports recent findings that its global biomass burning source appears to have been overestimated. Similarly, we found no evidence for emissions of chloroform (CHCl3) or methyl chloroform (CH3CCl3) from boreal forest fires. The speciated hydrocarbon measurements presented here show the importance of carbon released by short-chain NMVOCs, the strong contribution of pinene emissions from boreal forest fires, and the wide range of compound classes in the most abundantly emitted NMVOCs, all of which can be used to improve biomass burning inventories in local/global models and reduce uncertainties in model estimates of trace gas emissions and their impact on the atmosphere.

Simpson, I. J.; Akagi, S. K.; Barletta, B.; Blake, N. J.; Choi, Y.; Diskin, G. S.; Fried, A.; Fuelberg, H. E.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Wennberg, P. O.; Wiebring, P.; Wisthaler, A.; Yang, M.; Yokelson, R. J.; Blake, D. R.

2011-03-01

300

IMPACT OF A PRIMARY SULFATE EMISSION SOURCE ON AIR QUALITY  

EPA Science Inventory

A one-month study was carried out at an isolated oil-fired power plant in New York State to assess the impact of primary sulfate emissions on air quality. Emissions of total sulfate from the source varied from 22 kg/hr to 82 kg/hr per boiler with the sulfuric acid concentration a...

301

EMISSION INVENTORY IMPROVEMENT PROGRAM (EIIP) AREA SOURCE COMMITTEE  

EPA Science Inventory

The paper described activities and future plans of the Emission Inventory improvement Program (EIIP) Area Source Committee, as discussed during the November 2, 1994, EIIP panel discussion. he Committee will develop a set of preferred aid alternate methods for estimating air emiss...

302

Asbestos emissions from baghouse controlled sources.  

PubMed

There is virtually no information published on the absolute efficiency of baghouses in reducing the emmisions of fine particles of asbestos. This lack of information is unfortunate because serious occupational health problems may result from the common practice of recirculating air to conserve energy. Emission testing has been conducted at five asbestos processing plants where the emissions are controlled by baghouses. The results showed that the mass removal efficiency frequently exceeded 99.00%. Membrane filter samples of the effluent were examined by optical and electron microscope. It was observed that despite the high mass efficiency, the number of fibers emitted, which were greater than 1.5 mum in length, was about 10(4)-10(5) fibers/m3, while the number of fibers less than 1.5 mum was 10(7)-10(8) fibers/m3. The significance of the size of the fibers in terms of probably health impact is briefly discussed. PMID:1227285

Harwood, C F; Oestreich, D K; Siebert, P; Stockham, J D

1975-08-01

303

Highly nonlinear ozone formation in the Houston region and implications for emission controls  

Microsoft Academic Search

Photochemical modeling with high-order sensitivity analysis is applied to simulate the nonlinear responses of ozone to NOx and VOC emissions from different source regions in the Houston-Galveston-Brazoria area and their interactions. First-order responses of daytime ozone to Houston NOx emissions are typically positive but are negative in the core region, indicating a NOx-inhibited chemical regime there. Houston anthropogenic VOC emissions

Xue Xiao; Daniel S. Cohan; Daewon W. Byun; Fong Ngan

2010-01-01

304

Combustion sources of particles: 2. Emission factors and measurement methods.  

PubMed

Emissions from the combustion of biomass and fossil fuels are a significant source of particulate matter (PM) in ambient outdoor and/or indoor air. It is important to quantify PM emissions from combustion sources for regulatory and control purposes in relation to air quality. In this paper, we review emission factors for several types of important combustion sources: road transport, industrial facilities, small household combustion devices, environmental tobacco smoke, and vegetation burning. We also review current methods for measuring particle physical characteristics (mass and number concentrations) and principles of methodologies for measuring emission factors. The emission factors can be measured on a fuel-mass basis and/or a task basis. Fuel-mass based emission factors (e.g., g/kg of fuel) can be readily used for the development of emission inventories when the amount of fuels consumed are known. Task-based emission factors (g/mile driven, g/MJ generated) are more appropriate when used to conduct comparisons of air pollution potentials of different combustion devices. Finally, we discuss major shortcomings and limitations of current methods for measuring particle emissions and present recommendations for development of future measurement techniques. PMID:12492165

Zhang, Junfeng Jim; Morawska, Lidia

2002-12-01

305

VOC compliance on the ball: Aluminum can manufacturer rolls to California VOC compliance  

SciTech Connect

Since entering the North American beverage can market in 1969, Ball Corp., has increased its market share at a pace more than double the growth of the market itself. In addition to holding numerous patented advancements in can-making technology, Ball prides itself as an environmentally responsible company. When Ball decided to increase production capacity in its Fairfield, California, plant, the challenge was to produce more cans, while still complying with the state`s stringent air emissions regulations. As with other aluminum can manufacturing facilities, Ball`s coating and curing operations generate volatile organic compounds (VOCs). Ball`s permit from the state of California allows only limited amounts of VOC discharges into the atmosphere. With proposed increases in production capacities, however, the Bay Area`s Air Quality Management District--a local US EPA authority--required Ball to incinerate far more VOCs than the existing recuperative abatement system could handle. According to California regulations, facilities that wish to increase VOC emissions must install some type of VOC-control system or provide technological offsets. This regulatory pressure led Ball to seek a solution that would not only comply with emissions regulations, but would not compromise the company`s production process. Ball engineers selected a regenerative thermal oxidizer (RTO) for the Fairfield, Calif., plant. Considering the success Ball has encountered in previous experiences with this type of oxidation unit, the company immediately selected an RTO instead of catalytic oxidizers or other types of pollution control equipment.

Gay, R. [Engelhard Corp., Iselin, NJ (United States)

1997-07-01

306

Estimating DNAPL composition and VOC dilution from extraction well data  

Microsoft Academic Search

Field data from a large-scale ground-water extraction system at the Savannah River Site in South Carolina indicate that considerable dilution of volatile organic compounds (VOCs) occurs at extraction wells when compared with the effective solubilities of the VOC components (TCE and PCE) in the dense, nonaqueous phase liquid (DNAPL) source zone. This dilution is believed to be due to the

R. E. Jackson; P. E. Mariner

1995-01-01

307

Source profiles of volatile organic compounds associated with solvent use in Beijing, China  

NASA Astrophysics Data System (ADS)

Compositions of volatile organic compound (VOC) emissions from painting applications and printing processes were sampled and measured by gas chromatography-mass spectrometry/flame ionization detection (GC-MS/FID) in Beijing. Toluene and C8 aromatics were the most abundant species, accounting for 76% of the total VOCs emitted from paint applications. The major species in printing emissions included heavier alkanes and aromatics, such as n-nonane, n-decane, n-undecane, toluene, and m/p-xylene. Measurements of VOCs obtained from furniture paint emissions in 2003 and 2007 suggest a quick decline in benzene levels associated with formulation changes in furniture paints during these years. A comparison of VOC source profiles for painting and printing between Beijing and other parts of the world showed significant region-specific discrepancies, probably because of different market demands and environmental standards. We conducted the evaluation of the source reactivities for various VOC emission sources. The ozone formation potential (OFP) for unit mass of VOCs source emissions is the highest for paint applications. Substituting solvent-based paints by water-based in Beijing will lead to an OFP reduction of 152,000 tons per year, which is more than 1/4 of the OFPs for VOCs emissions from vehicle exhaust in the city.

Yuan, Bin; Shao, Min; Lu, Sihua; Wang, Bin

2010-05-01

308

CHARACTERIZATION OF NITROUS OXIDE EMISSION SOURCES  

EPA Science Inventory

The report presents a global inventory of nitrous oxide (N2O) based on reevaluation of previous estimates and additions of previously uninventoried source categories. (NOTE: N2O is both a greenhouse gas and a precursor of nitric oxide (NO) which destroys stratospheric ozone.) The...

309

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

Federal Register 2010, 2011, 2012, 2013

...Performance for Greenhouse Gas Emissions for New Stationary Sources: Electric...Performance for Greenhouse Gas Emissions for New Stationary Sources: Electric...Performance for Greenhouse Gas Emissions for New Stationary Sources:...

2012-05-04

310

EMISSIONS ASSESSMENT OF CONVENTIONAL STATIONARY COMBUSTION SYSTEMS: VOLUME V: INDUSTRIAL COMBUSTION SOURCES  

EPA Science Inventory

The report characterizes air emissions from industrial external combustion sources and is the last of a series of five reports characterizing emissions from conventional combustion sources. The emissions characterization of industrial combustion sources was based on a critical ex...

311

Classification of nutrient emission sources in the Vistula River system.  

PubMed

Eutrophication of the Baltic sea still remains one of the biggest problems in the north-eastern area of Europe. Recognizing the sources of nutrient emission, classification of their importance and finding the way towards reduction of pollution are the most important tasks for scientists researching this area. This article presents the chemometric approach to the classification of nutrient emission with respect to the regionalisation of emission sources within the Vistula River basin (Poland). Modelled data for mean yearly emission of nitrogen and phosphorus in 1991-2000 has been used for the classification. Seventeen subcatchements in the Vistula basin have been classified according to cluster and factor analyses. The results of this analysis allowed determination of groups of areas with similar pollution characteristics and indicate the need for spatial differentiation of policies and strategies. Three major factors indicating urban, erosion and agricultural sources have been identified as major discriminants of the groups. PMID:19232796

Kowalkowski, Tomasz

2009-06-01

312

Composite global emissions of reactive chlorine from anthropogenic and natural sources: Reactive Chlorine Emissions Inventory  

Microsoft Academic Search

Emission inventories for major reactive tropospheric Cl species (particulate Cl, HCl, ClNO2, CH3Cl, CHCl3, CH3CCl3, C2Cl4, C2HCl3, CH2Cl2, and CHClF2) were integrated across source types (terrestrial biogenic and oceanic emissions, sea-salt production and dechlorination, biomass burning, industrial emissions, fossil-fuel combustion, and incineration). Composite emissions were compared with known sinks to assess budget closure; relative contributions of natural and anthropogenic sources

William C. Keene; Archie McCulloch; Thomas E. Graedel; Jürgen M. Lobert; Michael L. Aucott; Sun Ling Gong; David B. Harper; Gary Kleiman; Pauline Midgley; Robert M. Moore; Christophe Seuzaret; William T. Sturges; Carmen M. Benkovitz; Valentin Koropalov; Leonard A. Barrie; Yi Fan Li

1999-01-01

313

Emissivity and detected incidance from a thermal source  

NASA Astrophysics Data System (ADS)

The incidence from a gray-body source detected in a wavelength interval is determined for a quantum and thermal detectors, for the ideal and non-ideal behavior. The results are applied to a common spectrometric reference source, a tungsten lamp, with measured, published emissivity values.

Paez, Gonzalo

2002-02-01

314

VOCs and IVOCs in the Los Angeles Basin: Quantification and Correlation to Regional Demographics  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) and intermediate volatility VOCs (IVOCs) are hydrocarbons that participate in chemical reactions affecting air quality and climate. VOCs and IVOCs, classified separately due to differences in effective saturation constants, both contribute to ozone and aerosol formation. IVOCs are not typically measured in ambient VOC studies because they are easily lost to sampling surfaces. Additionally, many VOCs and IVOCs, particularly aromatic hydrocarbons, are of concern because they have high respiratory uptake and accumulate in adipose tissue. The purpose of this study is to quantify VOCs and IVOCs in residential neighborhoods around the Los Angeles basin using a portable and inexpensive analytical method and to overlay these data with regional demographics. Hayesep-Q adsorbent cartridges were used to sample ambient air, followed by solvent extraction and analysis by Gas Chromatography and Mass Spectrometry (GC-MS). Data will be presented from a pilot study consisting of measurements made at 7 sites over 3 weeks in summer 2013. Results suggest a correlation between higher mixing ratios of anthropogenic compounds and low income status. For example, 92% of the variation in 1,2,3-trimethylbenzene concentrations can be explained by the linear relationship between these mixing ratios and the percentage of household income less than $20,000 in each neighborhood (R2 = 0.917). Communities most at risk from the emission of these compounds will likely be located near sources (i.e. roadways, freeways, flight paths) and thus are typically low-income and not a part of the California Air Resources Board monitoring system.

Carrasco, E.; Bouvier-Brown, N. C.

2013-12-01

315

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

316

Emission rates of benzene and ammonia area sources determined by spectroscopic remote measurements and inverse dispersion modeling  

NASA Astrophysics Data System (ADS)

The emission rates of diffuse and heterogeneous distributed sources are difficult to determine because point measurements are not representative. Therefore a method was further developed to determine gaseous emission rates by measurements of path-integrated mixing ratios with open-path spectroscopic systems in the exhaust plume (VOC, NH3, CH4, N2O, CO, CO2) and of meteorological parameters. Inverse dispersion modeling is used to quantify the emission rates afterwards with these data. The measurements are performed by Fourier Transform Infrared (FTIR) spectroscopy and Differential Optical Absorption Spectroscopy (DOAS) at 50 to 500 m optical path lengths about 1 to 20 m above ground level. The measurement accuracy for greenhouse gases and ammonia is about plus or minus 10% and for BTX about plus or minus 30%. The whole method was validated at a livestock building with a single exhaust chimney. The Gaussian model PAL was applied for inverse modeling to investigate limited pieces of land and isolated facilities in flat terrain. Including the accuracy of the dispersion simulations the determined emission rates have an error margin of about plus or minus 30%. Results of measurement campaigns are discussed as emission rates of ammonia from slurry spreading as well as of benzene from gas stations and a tank farm.

Schaefer, Klaus; Emeis, Stefan M.; Stockhause, Martina; Sedlmaier, Achim; Hoffmann, Herbert; Depta, Georg; Gronauer, Andreas

1999-02-01

317

Modeling VOC transport in simulated waste drums  

Microsoft Academic Search

A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in

K. J. Liekhus; G. L. Gresham; E. S. Peterson; C. Rae; N. J. Hotz; M. J. Connolly

1993-01-01

318

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

NASA Astrophysics Data System (ADS)

Mercury (Hg) is a toxic pollutant and is important to understand its cycling in the environment. In this dissertation, a number of modeling investigations were conducted to better understand the emission from natural surfaces, the source-receptor relationship of the emissions, and emission reduction of atmospheric mercury. The first part of this work estimates mercury emissions from vegetation, soil and water surfaces using a number of natural emission processors and detailed (LAI) Leaf Area Index data from GIS (Geographic Information System) satellite products. East Asian domain was chosen as it contributes nearly 50% of the global anthropogenic mercury emissions into the atmosphere. The estimated annual natural mercury emissions (gaseous elemental mercury) in the domain are 834 Mg yr-1 with 462 Mg yr-1 contributing from China. Compared to anthropogenic sources, natural sources show greater seasonal variability (highest in simmer). The emissions are significant, sometimes dominant, contributors to total mercury emission in the regions. The estimates provide possible explanation for the gaps between the anthropogenic emission estimates based on activity data and the emission inferred from field observations in the regions. To understand the contribution of domestic emissions to mercury deposition in the United States, the second part of the work applies the mercury model of Community Multi-scale Air Quality Modeling system (CMAQ-Hg v4.6) to apportion the various emission sources attributing to the mercury wet and dry deposition in the 6 United States receptor regions. Contributions to mercury deposition from electric generating units (EGU), iron and steel industry (IRST), industrial point sources excluding EGU and IRST (OIPM), the remaining anthropogenic sources (RA), natural processes (NAT), and out-of-boundary transport (BC) in domain was estimated. The model results for 2005 compared reasonably well to field observations made by MDN (Mercury Deposition Network) and CAMNet (Canadian Atmospheric Mercury Measurement Network). The model estimated a total deposition of 474 Mg yr-1 to the CONUS (Contiguous United States) domain, with two-thirds being dry deposited. Reactive gaseous mercury contributed the most to 60% of deposition. Emission speciation distribution is a key factor for local deposition as contribution from large point sources can be as high as 75% near (< 100 km) the emission sources, indicating that emission reduction may result in direct deposition decrease near the source locations. Among the sources, BC contributes to about 68% to 91% of total deposition. Excluding the BC's contribution, EGU contributes to nearly 50% of deposition caused by CONUS emissions in the Northeast, Southeast and East Central regions, while emissions from natural processes are more important in the Pacific and West Central regions (contributing up to 40% of deposition). The modeling results implies that implementation of the new emission standards proposed by USEPA (United States Environmental Protection Agency) would significantly benefit regions that have larger contributions from EGU sources. Control of mercury emissions from coal combustion processes has attracted great attention due to its toxicity and the emission-control regulations and has lead to advancement in state-of-the-art control technologies that alleviate the impact of mercury on ecosystem and human health. This part of the work applies a sorption model to simulate adsorption of mercury in flue gases, onto a confined-bed of activated carbon. The model's performances were studied at various flue gas flow rates, inlet mercury concentrations and adsorption bed temperatures. The process simulated a flue gas, with inlet mercury concentration of 300 ppb, entering at a velocity of 0.3 m s-1 from the bottom into a fixed bed (inside bed diameter of 1 m and 3 m bed height; bed temperature of 25 °C) of activated carbon (particle size of 0.004 m with density of 0.5 g cm-3 and surface area of 90.25 cm2 g -1). The model result demonstrated that a batch of activated carbon

Shetty, Suraj K.

319

Evaluating the dispersion of toxic odour emissions from complex sources.  

PubMed

This article describes an original approach for evaluating exposure to toxic odour emissions, based on methods commonly used for assessing the impact of odour, adopted in this specific case to examine the non-carcinogenic health effects of odours in the city of Terni, Italy. First the hazardous volatile organic compounds emitted from the main odour sources were identified and quantified by chemical analysis. The Hazard Index (HI) was used to assess the toxicity associated with the emissions. The HI is the sum of the concentrations of the hazardous compounds weighted with their Reference Concentration (RfC). A RfC is the estimated continuous inhalation concentration at which people are unlikely to risk any deleterious effects during their lifetime. Atmospheric dispersion modelling was based on the Toxicity Emission Rate (TER) which, like the Odour Emission Rate (OER) conventionally used to quantify odour emissions, relates the HI with the air flow of an emission source; it is as a simple but effective method for the general characterization of toxic odour emissions in complex scenarios. The results indicated that citizens' exposure to the non-carcinogenic toxic compounds involved in odour emissions was below the level expected to have adverse effects on human health. Classical risk assessment techniques should now be employed to define the pollutants and their effects better and to validate this approach. PMID:22506704

Capelli, L; Sironi, S; Del Rosso, R; Bianchi, G; Davoli, E

2012-01-01

320

Control for NOx Emissions from Combustion Sources  

NASA Technical Reports Server (NTRS)

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

PozodeFernandez, Maria E.; Collins, Michelle M.

2000-01-01

321

Distribution of airborne particles from multi-emission source.  

PubMed

The purpose of this work was to study the distribution of airborne particles in the surroundings of an iron and steel factory in southern Finland. Several sources of particulate emissions are lying side by side, causing heavy dust loading to the environment. This complicated multi-pollutant situation was studied mainly by SEM/EDX methodology. Particles accumulated on Scots pine bark were identified and quantitatively measured according to their element content, size and shape. As a result, distribution maps of particulate elements were drawn and the amount of different particle types along the study lines was plotted. Particulate emissions from the industrial or energy production processes were not the main dust source. Most emissions were produced from the clinker crusher. Numerous stockpiles of the industrial wastes and raw materials also gave rise to particulate emissions as a result of wind erosion. It was concluded that SEM/EDX methodology is a useful tool for studying the distribution of particulate pollutants. PMID:12807259

Kemppainen, Sari; Tervahattu, Heikki; Kikuchi, Ryunosuke

2003-06-01

322

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

Microsoft Academic Search

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

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

2008-01-01

323

The hollow cathode plume. A plasma emission source for solids  

NASA Astrophysics Data System (ADS)

A hollow cathode discharge serves to form an energetic plasma plume which exhibits intense emission characteristics. The sample cathode is sputtered in the discharge to produce an atomic population which then flows into the plume through an exit orifice for subsequent excitation. Atomic absorption and emission profiles in the plume are shown. Emission spectra of major and minor elements show strong atomic and ionic lines of sputtered species, particularly from the inner core of the plume. A sample in the form of a small disc can serve as the base of the hollow cathode for more convenient sample preparation. The source is believed to have potential also in elemental analysis by mass spectrometry.

Marcus, R. Kenneth; Harrison, W. W.

324

Source apportionment of volatile organic compounds measured in Edmonton, Alberta  

NASA Astrophysics Data System (ADS)

From 2003 to 2009, whole air samples were collected at two sites in Edmonton and analyzed for over 77 volatile organic compounds (VOCs). VOCs were sampled in the downtown area (Central site) and an industrial area on the eastern side of the city (East site). Concentrations of most VOCs were highest at the East site, with an average total VOC mass concentration of 221 ?g m-3. The average total VOC mass concentration at the Central site was 65 ?g m-3. The United States Environmental Protection Agency's positive matrix factorization receptor model (EPA PMF) was used to apportion ambient concentrations of VOCs into eleven factors, which were associated with emissions sources. On average, 94 and 99% of the measured mass were apportioned by PMF at the East and Central site, respectively. Factors include transportation combustion (gasoline and diesel), industrial sources (industrial evaporative, industrial feedstock, gasoline production/storage, industrial chemical use), mixed mobile and industrial (gasoline evaporative, fugitive butane), a biogenic source, a natural gas related source, and a factor that was associated with global background pollutants transported into the area. Transportation sources accounted for more than half of the reconstructed VOC mass concentration at the Central site, but less than 10% of the reconstructed mass concentration at the East site. By contrast, industrial sources accounted for ten times more of the reconstructed VOC mass concentration at the East site than at the Central site and were responsible for approximately 75% of the reconstructed VOC mass concentration observed at the East site. Of the six industrial factors identified at the East site, four were linked to petrochemical industry production and storage. The two largest contributors to the reconstructed VOC mass concentration at the East site were associated with fugitive emissions of volatile species (butanes, pentanes, hexane, and cyclohexane); together, these two factors accounted for more than 50% of the reconstructed VOC mass concentration at the East site in contrast to less than 2% of the reconstructed mass concentration at the Central site. Natural gas related emissions accounted for 10%-20% of the reconstructed mass concentration at both sites. Biogenic emissions and VOCs associated with well-mixed global background were less than 10% of the reconstructed VOC mass concentration at the Central site and less than 3% of the reconstructed mass concentration at the East site.

McCarthy, Michael C.; Aklilu, Yayne-Abeba; Brown, Steven G.; Lyder, David A.

2013-12-01

325

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

326

A compact PTR-ToF-MS instrument for airborne measurements of VOCs at high spatio-temporal resolution  

NASA Astrophysics Data System (ADS)

Herein, we report on the development of a compact proton-transfer-reaction time-of-flight mass spectrometer for airborne measurements of volatile organic compounds (VOCs). The new instrument resolves isobaric ions with a mass resolving power (m/?m) of ~ 1000, provides accurate m/z measurements (?m < 3 mDa), records full mass spectra at 1 Hz and thus overcomes some of the major analytical deficiencies of quadrupole-MS based airborne instruments. 1 Hz detection limits for biogenic VOCs (isoprene, ?-pinene), aromatic VOCs (benzene, toluene, xylenes) and ketones (acetone, methyl ethyl ketone) range from 0.05 to 0.12 ppbV, making the instrument well-suited for fast measurements in the continental boundary layer. The instrument detects and quantifies VOCs in locally confined plumes (< 1km) which improves our capability of characterizing emission sources and atmospheric processing within plumes. A deployment during the NASA 2013 DISCOVER-AQ mission generated high vertical and horizontal resolution in situ data of VOCs and ammonia for validation of satellite retrievals and chemistry transport models.

Müller, M.; Mikoviny, T.; Feil, S.; Haidacher, S.; Hanel, G.; Hartungen, E.; Jordan, A.; Märk, L.; Mutschlechner, P.; Schottkowsky, R.; Sulzer, P.; Crawford, J. H.; Wisthaler, A.

2014-06-01

327

Assessment of odorous VOCs released from a main MSW landfill site in Istanbul-Turkey via a modelling approach.  

PubMed

An air pollution modeling study was conducted to investigate the odorous effects of volatile organic compounds (VOCs) emissions from a sanitary landfill area on ambient air quality. The atmospheric dispersion of hydrogen sulfide (H(2)S) and 22 VOCs was modeled. Industrial Source Complex v3 Short Term (ISCST3) model was used to estimate hourly concentrations of odorous VOCs over the nearest residential area. Odor thresholds of VOCs of interest were also found in the literature. Results showed that short-term averages of three odorous VOCs, namely ethyl mercaptan, methyl mercaptan and hydrogen sulfide, exceeded their odor thresholds, which are reported to be 0.022, 0.138 and 11.1 microg/m(3), respectively, at several points within the domain. Their highest concentrations within Gokturk County were estimated to be 0.09387 microg/m(3) for ethyl mercaptan, 0.07934 microg/m(3) for methyl mercaptan and 6.315 microg/m(3) for hydrogen sulfide. Short-term model results revealed the occasional odor problems being reported for Gokturk County. Hourly concentrations were used to obtain frequencies of odor episodes in Gokturk County via a probability analysis. The results showed that ethyl mercaptan concentrations did not exceed its odor threshold during more than 8.84% of the time. Similarly, the maximum odor episode frequencies for methyl mercaptan and hydrogen sulfide were 0.98% and 0.34% of the time, respectively. PMID:19285797

Saral, Arslan; Demir, Selami; Yildiz, Senol

2009-08-30

328

Deposition of terpenes to vegetation - a paradigm shift towards bidirectional VOC exchange?  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) are important precursors for secondary organic aerosol (SOA) formation (Hallquist et al., 2009). In addition reactive BVOCs play a crucial role in local tropospheric ozone production (Atkinson, 2000). According to the present scientific understanding vegetation is recognized as a major VOC emission source rather than a deposition sink. Our recent observations however demonstrate that an uptake of terpene compounds to mountain grassland can be significant - at least under certain atmospheric conditions. After a severe hailstorm volume mixing ratios (VMR) of locally emitted terpene compounds originating from conifers located at the mountain slopes were strongly enhanced, even during daytime hours. Weeks after the hailstorm our PTR-MS and PTR-time-of-flight (PTR-TOF) instruments still measured deposition fluxes of monoterpenes (m/z 137.133), sesquiterpenes (m/z 205.195), and oxygenated terpenes (m/z 153.128) to the grassland. The total amount of terpenoids (on a carbon basis) deposited to the grassland during the weeks after the hailstorm is comparable to the total methanol emission of the entire growing season (Bamberger et al., 2011). These findings pose the question whether the terminology should be adjusted from VOC emission to VOC exchange.

Bamberger, I.; Hörtnagl, L.; Ruuskanen, T.; Schnitzhofer, R.; Müller, M.; Graus, M.; Karl, T.; Wohlfahrt, G.; Hansel, A.

2012-04-01

329

Air Emissions Guide for Air Force Mobile Sources: Methods for Estimating Emissions of Air Pollutants for Mobile Sources at U.S. Air Force Installations.  

National Technical Information Service (NTIS)

Provides a uniform approach to calculating air pollutant emissions for the most common mobile sources found at Air Force installations. This guide is the Air Force's single authoritative resource for mobile source emission estimating algorithms and emissi...

2013-01-01

330

Measurement of the VOC Environment from an Aircraft Platform during an Aerosol-Cloud Interaction Study Near Oklahoma City  

NASA Astrophysics Data System (ADS)

The interaction and relationship between atmospheric aerosols and ambient VOC concentrations is a current area of activity in atmospheric research both in urban and remote environments. Current atmospheric models seriously under predict the amount of secondary organic aerosol (SOA), highlighting the importance of simultaneous particle and VOC measurements and their importance to climate change models. The Cumulus Humilis Aerosol Processing Study (CHAPS) campaign was conducted in June of 2007 near Oklahoma City to investigate the mutual interaction of anthropogenic aerosols and clouds on each other. An important part of this study was characterizing the temporally and spatially resolved VOC environment in which urban aerosols and cumuliform clouds in the Oklahoma City environment exist. We report results from the proton transfer reaction mass spectrometer (PTR-MS) aboard the DOE Gulfstream 1 (G1) research aircraft to perform time-resolved measurements of the ambient VOC species and concentrations in conjunction with the suite of aerosol, trace gas and meteorological instruments aboard the G1. Several classes of VOC's were observed. Benzene, toluene, C2-benzenes and other species indicative of primary urban emissions were found in the Oklahoma City plume, strongly correlated with CO and other inorganic urban trace gases. Oxygenated species such as methanol, acetone and acetaldehyde were observed with no well defined spatial or temporal variation. Finally, species typical of biogenic emissions, isoprene and its oxidation products were seen in broad but definite spatial distributions, not correlated with the urban gas phase products as measured with the PTR-MS and other instrumentation. The concentration levels of these species and possible ground-based sources will be investigated and reported in this presentation. Correlation with aerosol instrumentation such as the Aerodyne aerosol mass spectrometer (AMS), nephelometer and other optical measurements will also be reported, both within and out of cloud environments. These correlations will be examined for possible influences of the local VOC species on the cloud-aerosol systems under study.

Alexander, M. L.; Newburn, M.; Hubbe, J.; Berg, L.; Berkowitz, C.; Springston, S.; Senum, G.; Lee, Y.; Andrews, E.

2007-12-01

331

FEASIBILITY OF DEVELOPING SOURCE SAMPLING METHODS FOR ASBESTOS EMISSIONS  

EPA Science Inventory

The objective of this program was to determine the feasibility of developing methods for sampling asbestos in the emissions of major asbestos sources: (1) ore production and taconite production, (2) asbestos-cement production, (3) asbestos felt and paper production, and (4) the p...

332

SOURCE EMISSION TESTS AT THE BALTIMORE DEMONSTRATION PYROLYSIS FACILITY  

EPA Science Inventory

TRW was retained by EPA/IERL Cincinnati in May of 1976 to conduct source emission tests at a solid waste treatment plant in Baltimore, Maryland. The plant is designed to recover low-grade fossil fuel from non-toxic solid waste by the use of a process known as pyrolysis. When plan...

333

PCB EMISSIONS FROM STATIONARY SOURCES: A THEORETICAL STUDY  

EPA Science Inventory

The report gives results of a theoretical assessment of polychlorinated biphenyl (PCB) formation and destruction in conventional fossil fuel fired sources. Results suggest a small but finite possibility that PCB isomers may be found in their emissions. The study was the result of...

334

MEASURING INORGANIC AND ALKYL LEAD EMISSIONS FROM STATIONARY SOURCES  

EPA Science Inventory

Described are the results from studies done to provide test methods for state and local air pollution control agencies to measure accurately the lead emissions from stationary source stacks as required in the National Ambient Air Quality Standard for Lead. Inorganic lead is colle...

335

COMPARATIVE STUDY OF OPEN SOURCE PARTICULATE EMISSION MEASURING TECHNIQUES  

EPA Science Inventory

The paper gives results of a comparative study of variations in measuring and analytical techniques used to assess sources upon which emission factor data bases are built (in an effort to quantify these technique-dependent parameters). The study included a simultaneous, side-by-s...

336

Intelligent location of two simultaneously active acoustic emission sources  

Microsoft Academic Search

Acoustic emission (AE) analysis is used for characterization and location of developing defects in materials. The location of AE on complicated aircraft frame structures is a difficult problem of non-destructive testing. This article describes an intelligent AE source locator which comprises a sensor antenna and a general regression neural network, which solves the location problem based on learning from examples.

Tadej Kosel; Igor Grabec; Franc Kosel

2005-01-01

337

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

EPA Science Inventory

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

338

Characterization of nitrous oxide emission sources. Final report  

SciTech Connect

Nitrous oxide (N2O) is both a greenhouse gas and a precursor of nitric oxide (NO), which destroys stratospheric ozone. This study presents a global N2O inventory based on re-evaluation of previous estimates and additions of previously uninventoried source categories. The best estimate of anthropogenic N2O is 5.7 Tg/yr, which is still much lower than natural source emissions. Much uncertainty remains about estimates for many source categories. Inadequate data are available for some categories; others are limited by a lack of reliable functional models of factors affecting emmissions rates.

Peer, R.L.; Epner, E.P.; Billings, R.S.

1995-07-01

339

Source characteristics of Jovian narrow-band kilometric radio emissions  

NASA Astrophysics Data System (ADS)

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

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

1993-07-01

340

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

Code of Federal Regulations, 2013 CFR

...limiting particulate matter emissions from wood products industry sources. 49.128...limiting particulate matter emissions from wood products industry sources. (a) What...matter that may be emitted from certain wood products industry sources operating...

2013-07-01

341

ProVoc  

NSDL National Science Digital Library

Learning a new language can be daunting, but this handy application can make this process a bit friendlier. With ProVoc, users can download existing vocabulary sets for English, French, German, Italian, Spanish, Danish, and dozens of other languages. After that, they can run through these words at their leisure on their computer or their iPod for convenience. Finally, the site also includes a FAQ section that answers any number of topical questions about the application. This version is compatible with computers running Mac OS X 10.3 and newer.

2007-01-01

342

Gap-filling strategies for annual VOC flux data sets  

PubMed Central

Up to now the limited knowledge about the exchange of volatile organic compounds (VOCs) between the biosphere and the atmosphere is one of the factors which hinders more accurate climate predictions. Complete long-term flux data sets of several VOCs to quantify the annual exchange and validate recent VOC models are basically not available. In combination with long-term VOC flux measurements the application of gap-filling routines is inevitable in order to replace missing data and make an important step towards a better understanding of the VOC ecosystem-atmosphere exchange on longer time scales. We performed VOC flux measurements above a mountain meadow in Austria during two complete growing seasons (from snowmelt in spring to snow reestablishment in late autumn) and used this data set to test the performance of four different gap-filling routines, mean diurnal variation (MDV), mean gliding window (MGW), look up tables (LUT) and linear interpolation (LIP), in terms of their ability to replace missing flux data in order to obtain reliable VOC sums. According to our findings the MDV routine was outstanding with regard to the minimization of the gap-filling error for both years and all quantified VOCs. The other gap-filling routines, which performed gap-filling on 24 h average values, introduced considerably larger uncertainties. The error which was introduced by the application of the different filling routines increased linearly with the number of data gaps. Although average VOC fluxes measured during the winter period (complete snow coverage) were close to zero, these were highly variable and the filling of the winter period resulted in considerably higher uncertainties compared to the application of gap-filling during the measurement period. The annual patterns of the overall cumulative fluxes for the quantified VOCs showed a completely different behavior in 2009, which was an exceptional year due to the occurrence of a severe hailstorm, compared to 2011. Methanol was the compound which contributed with 381.5 mgCm?2 and 449.9 mgCm?2 most to the cumulative VOC carbon emissions in 2009 and 2011, respectively. In contrast to methanol emissions, however, considerable amounts of monoterpenes (?327.3 mgCm?2) were deposited to the mountain meadow in consequence to the hailstorm in 2009. Other quantified VOCs had considerably lower influences on the annual patterns.

Bamberger, I.; Hortnagl, L.; Walser, M.; Hansel, A.; Wohlfahrt, G.

2013-01-01

343

Surface-emission monitoring for formaldehyde source-strength analysis  

SciTech Connect

A passive surface-emission monitor has been developed for non-destructive measurement of formaldehyde (CH/sub 2/O) emission rates from CH/sub 2/O resin-containing materials such as urea-formaldehyde foam insulation (UFFI) and pressed-wood products. The monitor seals with the flat surface of a solid CH/sub 2/O emission source. The emitted CH/sub 2/O is sorbed by a planar distribution of solid sorbent (13X molecular sieve), supported at a fixed distance from the test medium. The CH/sub 2/O uptake of the exposed molecular sieve can be determined using a water-rinse desorption and colorimetric-analysis procedure. A detection limit of approximately 0.03 mg CH/sub 2/O/m/sup 2/h is achieved with a 20.3 cm diameter monitor using a three-hour collection period. Measurements of the CH/sub 2/O emission rate from pressed-wood products show strong correlations between the surface-emission monitor and environmentally controlled chamber tests. Formaldehyde emission-rate measurements of UFFI encased in simulated exterior wall panels also show strong correlations between the surface monitor and an air-flow monitoring technique.

Matthews, T.G.

1983-01-01

344

Stress-induced biogenic VOC emissions from typical European tree species, their impact on secondary organic aerosol formation and possible climate feedbacks  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOC) are precursors of secondary organic aerosols (SOA), which can scatter and absorb radiation. BVOC therefore indirectly impact the Earth's climate. Earth's climate is projected to change, possibly putting and vegetation under stress due to intensive heat and drought periods. Such stress situations will alter BVOC emissions that may induce feedbacks between vegetation and climate change. The main aim of our study is to determine whether such effect exists. A first step was to determine the impacts of drought and heat on BVOC emissions and subsequent SOA formation. Experiments were performed in the Juelich plant atmosphere chamber. Pine and Spruce were taken as representatives for species exhibiting storage organs for monoterpenes (MT). Beech and Birch were used as species with MT emissions closely coupled to CO2 uptake. The plants were stored under well-defined conditions of temperature and light intensity. Heat stress was induced by increasing the chamber temperature; drought stress was induced by not irrigating the plants. A fraction of the air leaving the plant chamber was fed into a reaction chamber where SOA formation was induced by OH-initiated oxidation. During stress situations the plants' BVOC emissions changed significantly. As a general feature we found that combined heat and drought stress increased MT emissions from conifers but decreased MT emissions from the broadleaf species. The former was attributed to a heat-induced breakdown of storage organs. The latter was attributed to a general breakdown of biosynthetic activity. SOA formation potentials were changed together with the MT emissions. The decrease in SOA formation potential due to the decrease of MT emissions from broadleaf species was amplified by additional emissions of green leaf volatiles (GLV). Obviously, GLV can suppress SOA formation by suppressing OH concentrations. GLV were also emitted from the conifers under heat stress. However the contribution of GLV to the BVOC mix was too low to suppress SOA formation significantly. Therefore, increases of MT emissions from heat stressed conifers followed by an increased SOA formation potential might be seen as a process leading to a negative climate feedback. This hypothesis was contested by the observation of a heat stress induced breakdown of pathogen-induced BVOC emissions. Conifers infested by aphids showed strong emissions of SQT and BVOC synthesized downstream of the shikimate pathway. Also these emissions are closely coupled to the CO2 uptake. Hence, these emissions vanished after heat stress causing a strong decrease of the SOA formation potential. At this stage it is difficult to assess whether heat and drought stress cause a negative or a positive feedbacks between vegetation and climate. Nevertheless, we conclude that such feedbacks exist. Key words: BVOC, SOA formation

Kleist, E.; Mentel, T. F.; Andres, S.; Dal Maso, M.; Hohaus, T.; Kindler-Scharr, A.; Rudich, Y.; Springer, M.; Tillmann, R.; Uerlings, R.; Wahner, A.; Wildt, J.

2011-12-01

345

Accurate Simulation of Acoustic Emission Sources in Composite Plates  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

346

Volatile organic compounds in suburban Ankara atmosphere, Turkey: Sources and variability  

NASA Astrophysics Data System (ADS)

In this study, concentrations of approximately 30 VOCs were measured, between January and June 2008 at a university campus in Ankara. Concentrations of measured VOCs are lower than corresponding concentrations reported for other cities in literature. Average concentrations of the measured VOCs ranged from 0.04 to 7.89 ?g m- 3. Benzene (2.18 ?g m- 3), toluene (7.89 ?g m- 3), ethylbenzene (0.85 ?g m- 3) and xylenes (2.62 ?g m- 3) (BTEX) were found as a major organics in suburban Ankara atmosphere. The measured VOCs also show well defined diurnal and weekday-weekend cycles. Toluene-to-benzene ratio (T/B) suggested that non-traffic sources can be important during summer months. The m,p-xylene-to-ethylbenzene ratio (X/E) pointed to transport of organic compounds from high-emission districts of the city. Positive matrix factorization applied to data revealed four sources, including gasoline exhaust, solvent evaporation, diesel emissions and a local laboratory source, contributing to VOC concentrations. Strengths of these sources, particularly solvent source, on total VOC concentrations showed seasonal differences. Source contributions on light and heavy VOCs were also different.

Yurdakul, Sema; Civan, Mihriban; Tuncel, Gürdal

2013-02-01

347

The Effect of VOC Speciation on Ozone and Carbon Monoxide Concentrations  

NASA Astrophysics Data System (ADS)

An update of the VOC speciation for use in models is needed, however, such an update is no small task. In order to understand the possible impact that an updated speciation might have on ozone formation and carbon monoxide concentrations an initial study focused on the VOC speciation within the solvent sector was carried out. NMVOC emissions from the solvent sector are typically among the largest contributions to total anthropogenic NMVOC emissions, along with the transport sector. In a number of cases disagreements have been found where attribution in emission inventories cite the largest sectoral contribution to solvents, while measurements indicate that the traffic sector remains the largest source of anthropogenic NMVOC emissions in urban areas. Regardless, solvent sector emissions remain substantial. And while some updates to the speciation of NMVOCs in the transport sector have been made, this has not been the case for solvents. A variety of solvent sector profiles from the literature show significant differences in their speciation. These profiles were used to conduct an initial (box) modeling study to determine the influence of NMVOC solvent sector speciation on resulting ozone formation and carbon monoxide concentrations. The evolution of NMVOC speciation within the solvent sector over time was considered for countries where data was available, the UK and Greece. The scope of the effect of a change in speciation was also considered within the context of the general anthropogenic NMVOC speciation that included all anthropogenic sectors, and the relative contribution of the solvent sector to total NMVOC emissions. These results will inform further work that aims to provide an updated VOC speciation for use in models. Such improvements could provide a more robust understanding and prediction capacity for air quality and ozone in particular, specifically for the quantification of ozone pollution over Europe. Given limited data, this research aims to provide guidelines for the most relevant improvements needed to optimize research efforts.

von Schneidemesser, Erika; Coates, Jane; Denier van der Gon, Hugo; Butler, Tim

2014-05-01

348

The infrared emission bands. III. Southern IRAS sources.  

PubMed

We present airborne 5-8 micrometers spectra of southern IRAS sources which reveal strong polycyclic aromatic hydrocarbon (PAH) emission features. The good correlation between the bands, in particular the dominant 6.2 and "7.7" micrometers features, strongly imply a common carrier, reinforcing the PAH hypothesis. However, small but detectable spectral variations exist. Planetaries have a distinctly different ratio of I(6.2)/I(7.7) than other nebulae, accompanied by a redward shift in the actual wavelength of the "7.7" micrometers peak. Further, we have detected a new feature, previously predicted from laboratory spectra of PAH molecules, at 5.2 micrometers in many of these sources. Spectra of two rare [WC 10] planetary nebular nuclei indicate a very prominent plateau of emission, linking the 6.2 and 7.7 micrometers bands. Several of our sources show definite evidence for emission structure between 14 and 23 micrometers in their IRAS Low-Resolution Spectral Atlas spectra: we attribute this structure to PAH bands. too. We have defined the "generic" spectrum of emission bands relating the mean intensities of each band to that of the strongest, near 7.7 micrometers. We have added three more planetary or protoplanetary nebulae to our correlation between 7.7 micrometers band intensity and nebular gas phase C/O ratio, namely NGC 6302, HR 4049, and the highly carbon-rich [WC 10] nucleus, CPD--56 degrees 8032. For the latter we have determined a ratio for C/O of approximately 4.8 from IUE observations. The good correlation between the intensity ratio of the "7.7" micrometers feature relative to the far-infrared dust continuum and nebular C/O also supports a carbonaceous carrier for these emission features. PMID:11542167

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

1989-06-01

349

Review of volatile organic compound source apportionment by chemical mass balance  

NASA Astrophysics Data System (ADS)

The chemical mass balance (CMB) receptor model has apportioned volatile organic compounds (VOCs) in more than 20 urban areas, mostly in the United States. These applications differ in terms of the total fraction apportioned, the calculation method, the chemical compounds used in the calculation, the apportionment units, and the source profiles applied. Nevertheless, they show similar results for VOC fractions contributed by different sources. Gasoline vehicle exhaust, liquid gasoline, and gasoline evaporation contribute up to 50% or more of the ambient VOCs in many of these studies. Relative motor vehicle source contributions determined by CMB were similar to or larger than their proportions in emissions inventories. Coatings and solvent contributions from CMB were much lower than the proportions attributed to these sources in current emissions inventories. Several measurement and reporting conventions would facilitate CMB analyses of VOC data sets.

Watson, John G.; Chow, Judith C.; Fujita, Eric M.

350

Total organics guidance manual for stationary source emissions  

SciTech Connect

A guidance manual, prepared under EPA contract, was written to catalogue the methods used to measure and report total organics data from stationary source emissions. The guidance manual identifies specific techniques to determine the total organics sampled from stationary combustion sources. To generate a value for total organics, organics data from three specific boiling point/vapor pressure classes are combined: light hydrocarbons and volatile organics (measured using Field Gas Chromatography and Purge and Trap Gas Chromatography), semivolatile organics (measured using a total chromatographic organics method), and nonvolatile organic compounds (measured using a gravimetric analysis method). The methods for measuring and reporting the individual parameters are discussed in detail in the guidance manual.

Coppedge, E.A.; Johnson, L.D.; Martz, R.F.; Bursey, J.T.; Merrill, R.G.

1996-12-31

351

The speciation of volatile organic compounds (VOCs) from motorcycle engine exhaust at different driving modes  

NASA Astrophysics Data System (ADS)

This study investigated the emissions of volatile organic compound (VOC) from motorcycle engine exhaust at different driving modes on a dynamometer. The speciations and the ozone formation potential of VOC samples also had been investigated by GC/MS and maximum increment reactivity (MIR), respectively. Both brand new and in-use motorcycles were tested in this study. The tested motorcycles include 2-stroke and 4-stroke engines. There are totally 48 VOC compounds identified in this study. Only the VOC species with C 3-C 9 were identified successfully. Experimental results indicated that isopentane, toluene, m, p-xylene, n-pentane, 2-methylpentane, 3-methylpentane, benzene, n-heptane and methylheptane were the major VOC speciations in the motorcycle engine exhaust. The amount of VOC emissions of the in-use 2-stroke motorcycles was 5 times that of the new 2-stroke motorcycles and the in-use 4-stroke motorcycles was 15 times that of the new 4-stroke motorcycles during the whole cycle. The amount of VOC speciation concentration during idle and deceleration stages was higher than those during the acceleration and cruising modes. However, the emission rate of VOCs at various driving modes tested on a dynamometer had not been precised enough due to the inconsistent variation of volume efficiency of motorcycle engine. These data shows a clear distinct emission rate of VOC at various driving modes. Besides, alkanes and aromatics were the major VOC speciation groups in the motorcycle engine exhaust. The amount of VOCs contributed from 23% to 76% THC for the four types motorcycle. Great variation of VOC/THC were found among new and in-use motorcycle. The ozone formation potential of a 2-strokes engine was higher than that of a 4-stroke engine. The ozone formation potential of in-use motorcycles were also clear higher than those of new motorcycles.

Tsai, Jiun-Horng; Chiang, Hung-Lung; Hsu, Yi-Chun; Weng, Hung-Cheng; Yang, Chang-Yu

352

Carbonyl emissions from vehicular exhausts sources in Hong Kong.  

PubMed

Vehicular emission (VE) is one of the important anthropogenic sources for airborne carbonyls in urban area. Six types of VE-dominated samples were collected at representative locations in Hong Kong where polluted by a particular fueled type of vehicles, including (i) a gas refilling taxis station (liquefied petroleum gas [LPG] emission); (ii) a light-duty passenger car park (gasoline emission); (iii) a minibus station (diesel emission); (iv) a single-deck-bus depot (diesel emission); (v) a double-deck-bus depot (diesel emission); and (vi) a whole-food market entrance for light- and heavy-duty vehicles (diesel emission). A total of 15 carbonyls in the samples were quantified. Formaldehyde was the most abundant carbonyl among the VE-dominated samples, and its contribution to the total quantified amount on a molar basis ranged from 54.8% to 60.8%. Acetaldehyde and acetone were the next two abundant carbonyls. The carbonyls were quantified at three roadside locations in Hong Kong. The highest concentrations of formaldehyde and acetaldehyde, 22.7 +/- 8.4 and 6.0 +/- 2.8 microg/m3, respectively, were determined in the samples collected at a main transportation gate for goods between Hong Kong and Mainland China. The total quantified carbonyl concentration, 37.9 +/- 9.3 microg/m3, was the highest at an entrance of a cross-harbor tunnel in downtown area. The theoretical carbonyls compositions of the three roadside locations were estimated according to the VE-dominated sample profiles and the statistics on vehicle numbers and types during the sampling period. The measured compositions of formaldehyde were much higher than the theoretical compositions in summer, demonstrating that photochemical reactions significantly contributed to the formaldehyde production in the roadsides. PMID:22442938

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

2012-02-01

353

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

SciTech Connect

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

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

2014-01-01

354

Atmospheric Pollution and Emission Sources in South Asian Urban Region  

NASA Astrophysics Data System (ADS)

Rapid urbanization, and lack of efficient monitoring and control of pollution, along with phenomena like Asian Brown Haze or prolonged episodes of winter fog, makes the South Asian atmospheric chemistry a very complex one. The anthropogenic aerosols released from this region are projected to become the dominant component of anthropogenic aerosols worldwide in the next 25 years (Nakicenovic and Swart, 2000). The region is one of the most densely populated in the world, with present population densities of 100-500 persons km-2. There are six big cities, namely, Delhi, Dhaka, Karachi, Kolkata, Lahore, and Mumbai, each housing a population around or above 10 million. There is now a real concern about the sustainability of the region's ability to support the population due to air pollution, loss of biodiversity and soil degradation. Therefore, we conducted several extensive campaigns over last 10 years in Lahore, Karachi, and Islamabad in Pakistan to (1) chemically characterize the aerosols (PM2.5 mass, concentrations of trace elements, ions, black and organic carbon), and gaseous pollutants (concentrations of NH3, SO2, HONO, HNO3, HCl and (COOH)2, and (2) identify the major emission sources in this region. Exceedingly high concentrations of all species, relative to major urban areas of US and Europe, were observed. Concentrations of PM2.5, BC, Pb, SO42-, NH4+, HONO, NH3 respectively, up to 476, 110, 12, 66, 60, 19.6 and 50 ?gm-3 were observed in these cities, which were far in excess of WHO and US EPA air quality standard (Biswas et al., 2008). We use air parcel back trajectories, intercomponent relationships and meteorological observations to explain chemistry and emission sources of aerosol constituents. Carbonaceous aerosols contributed up to 69% of the PM2.5 mass (Husain et al., 2007). Source apportionment was conducted using positive matrix factorization. The analysis has classified six emission sources of aerosol components, namely, industrial activities, wood burning, secondary aerosols, metal processing, vehicular emissions, and crustal and road dust. Findings of our study will play a vital role in adopting a strategy to regulate emissions, and to mitigate the long-term climate change in the region. References: Nakicenovic, N. and Swart, R., 2000. In: N. Nakicenovic and R. Swart, Eds, Emissions Scenarios 2000. Special Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge. Biswas, K.F., Ghauri, B.M., Husain, L., 2008. Gaseous and aerosol pollutants during fog and clear episodes in South Asian urban atmosphere. Atmospheric Environment, 42, 7775-7785. Husain, L., Dutkiewicz, V.A., Khan, A.J., Ghauri, B.M., 2007. Characterization of carbonaceous aerosols in urban air. Atmospheric Environment, 41, 6872-6883.

Biswas, K. F.; Husain, Liaquat

2009-04-01

355

Atmospheric measurement of point source fossil CO2 emissions  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

356

Simple Ion Source with High Emission Current Density  

NASA Astrophysics Data System (ADS)

Simple version of ion source for production of the ion beams with high emission current density (up to 0.6 A/cm2) will be discussed. Discharge in Penning cell with permanent ceramic magnets have been used for plasma production. Using of the LaB6 self-heated cathodes have been decreased a discharge voltage up to 80 V, increased an efficiency of ion generation,suppressed a sputtering, increased lifetime. Small holes on the axis of catodes used for gas injection and for ion beam extraction along the magnetic field. Hollow cathode discharge increase a plasma concentration on the source axis and improve a gas efficiency of hydrogen ion production up to 60% and proton content more than 60% with the discharge current 0.8 A. Conditions for long time support of the noisless discharge, optimal for high brightness ion beam production have been found. Efficiency g of high current density ion beam production, determined as emission current density j divided to the full discharge power P for this source is up to 10 A/cm2 kW. For other high efficient ion source g= 0.2-0.05 A/cm2 kW is typical.

Dudnikov, Vadim; Farrell, J. Paul

1998-04-01

357

Source signature of volatile organic compounds from oil and natural gas operations in northeastern Colorado.  

PubMed

An extensive set of volatile organic compounds (VOCs) was measured at the Boulder Atmospheric Observatory (BAO) in winter 2011 in order to investigate the composition and influence of VOC emissions from oil and natural gas (O&NG) operations in northeastern Colorado. BAO is 30 km north of Denver and is in the southwestern section of Wattenberg Field, one of Colorado's most productive O&NG fields. We compare VOC concentrations at BAO to those of other U.S. cities and summertime measurements at two additional sites in northeastern Colorado, as well as the composition of raw natural gas from Wattenberg Field. These comparisons show that (i) the VOC source signature associated with O&NG operations can be clearly differentiated from urban sources dominated by vehicular exhaust, and (ii) VOCs emitted from O&NG operations are evident at all three measurement sites in northeastern Colorado. At BAO, the reactivity of VOCs with the hydroxyl radical (OH) was dominated by C(2)-C(6) alkanes due to their remarkably large abundances (e.g., mean propane = 27.2 ppbv). Through statistical regression analysis, we estimate that on average 55 ± 18% of the VOC-OH reactivity was attributable to emissions from O&NG operations indicating that these emissions are a significant source of ozone precursors. PMID:23316938

Gilman, J B; Lerner, B M; Kuster, W C; de Gouw, J A

2013-02-01

358

The Sources of F10.7 Emission  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

359

VHE emission from extragalactic sources: open issues from MWL observations  

NASA Astrophysics Data System (ADS)

The Cherenkov telescopes observations together with Fermi/LAT survey and multi-wavelength (MWL) simultaneous coverage are posing new challenges to the description of extreme sources, such as BL Lacs, flat spectrum radio quasars (FSRQs), and radiogalaxies. We will review some of these new results threatening the conventional emission models. Among them: the difficulties of the usual description with single-zone SSC models of the SED of BL Lacs objects, when simultaneous very-high energy (VHE) and MWL observations are taken into account; the constraints on the location of the gamma-ray emission region as revealed by the MAGIC observations of the FSRQ PKS 1222+21; the firm VHE detection of somewhat unexpected sources such as the radiogalaxy IC 310 in the Perseus cluster of galaxies. We will also consider the interplay between intrinsic emission models and the interaction of gamma-rays with the extragalactic background light and intergalactic magnetic fields. These issues will be tackled in the framework of the results of MWL observations led by the MAGIC Cherenkov telescopes system.

Stamerra, A.

2013-06-01

360

The Sources of F10.7 Emission  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

361

Thermal response and recyclability of poly(stearylacrylate- co -ethylene glycol dimethacrylate) gel as a VOCs absorbent  

Microsoft Academic Search

The development of absorbent materials for volatile organic compounds (VOCs) is in demand for a variety of environmental applications\\u000a including protective barriers for VOCs point sources. One of the challenges for the currently available VOCs absorbents is\\u000a their recyclability. In this study, we synthesized poly(stearylacrylate-co-ethylene glycol dimethacrylate) (NG-18) gels, and after rigorous characterization, investigated the absorption properties\\u000a for VOCs. The

Masahiko Ohta; Veera M. Boddu; Minori Uchimiya; Kazuki Sada

2011-01-01

362

Major sources of exposure to benzene and other volatile organic chemicals  

Microsoft Academic Search

The major sources of human exposure to about a dozen volatile organic chemicals (VOCs) have recently been identified. For nearly every chemical, the major sources of exposure are completely different from the major sources of emissions. This finding implies that current environmental regulations and control strategies are misdirected. Important sources of exposure are typically not regulated in any way, whereas

Lance Wallace

1990-01-01

363

Polar and non-polar volatile organic compounds (VOCs) in urban Algiers and saharian sites of Algeria  

NASA Astrophysics Data System (ADS)

For the first time, polar and non-polar organic compounds from C 4 to C 20 have been identified and quantified in one urban and two saharan sites located in Algeria. They were collected on adsorption traps filled with graphitic carbons and analyzed by high-resolution gas chromatography-mass spectrometry after thermal desorption. More than 190 compounds released by man-made and biogenic sources or formed in air by degradation of photochemical smog precursors were identified in the city center of Algiers. Some of them were never reported before. During our determinations, high levels of pollution characterized the city. Transport of anthropogenic pollutants together with some biogenic emission from date palm trees was mainly responsible for the levels of VOCs measured in Melika oasis located at the entrance of the Sahara desert. Background tropospheric levels of VOCs were instead detected in Bouchene sandy site of the Sahara desert where no biogenic sources were present.

Yassaa, Noureddine; Meklati, Brahim Youcef; Brancaleoni, Enzo; Frattoni, Massimiliano; Ciccioli, Paolo

364

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

EPA Science Inventory

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

365

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

EPA Science Inventory

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

366

EMISSIONS ASSESSMENT OF CONVENTIONAL STATIONARY COMBUSTION SYSTEMS: VOLUME IV. COMMERCIAL/INSTITUTIONAL COMBUSTION SOURCES  

EPA Science Inventory

The report characterizes air emissions from commercial/institutional external combustion sources and reciprocating engines and is the fourth of a series of five project reports characterizing emissions from conventional combustion sources. This characterization was based on a cri...

367

Emission features of a conventional radio frequency glow discharge source and a magnetically enhanced source  

NASA Astrophysics Data System (ADS)

A side-on-viewed source was developed in order to determine spatial emission features of a radio frequency (rf)-powered glow discharge. The discharge was formed inside a stainless steel T-shaped cell, which acted as the grounded anode. The cathode assembly was inserted into the leg of the T with the cathode situated near the T intersection. The resulting plasma was formed in the long arm of the T and was viewed through a window at one end of the T. Spatial profiles of Ar emission at 420 nm, Cu emission at 324 nm, and OH band emission at 309 nm were collected with an imaging spectrometer. The source was operated over a pressure range of 0.1-1.0 torr at rf power levels between 20 and 50 W. A power supply was employed at frequencies of 3.5, 6.78, and 13.56 MHz in order to determine the effect of driving frequency. The source was then modified by the placement of two magnets (either cobalt-samarium or ceramic) on its exterior. The magnets were placed on opposite sides of the T next to the cathode in order to create a transverse magnetic field in the region of the discharge above the cathode surface. The effect of the applied magnetic field on the voltage characteristics, sputtering rate, and spatial emission features of the source were then explored. Detection limits of the magnetically modified source for Monel 400 samples (Ni/Cu alloy) were also determined (10-50 ppm) using a high-resolution photodiode-array spectrometer.

Heintz, M. J.; Galley, P. J.; Hieftje, G. M.

1994-07-01

368

Identifying Dust Sources in North Africa and Modeling Patterns of Dust Emissions From These Sources  

NASA Astrophysics Data System (ADS)

Atmospheric models are requiring more accurate representations of the surface in modeling emissions of dust from the surface and the nutrients attached to fine mineral particles. Regional to continental scale characterization of surface landforms that are susceptible to erosion has become possible with the advent of satellites that monitor the land surface at moderate spectral and spatial resolution (e.g. MODIS). The most productive dust sources in the world are in the Sahara Desert and the Sahel, in areas where human pressures may be making the landscape more susceptible to wind erosion. This project seeks to model dust emissions in the Sahara and Sahel with estimates of surface parameters from satellite imagery and ancillary data. A map of landforms for Africa, north of 10 degrees, was constructed using a multiple endmember spectral mixture analysis (MESMA) of the MODIS 500 meter, 7 band, reflectance product. The magnitude of surface winds acting on the landforms was determined from forecast models. Surface parameters (vegetation characteristics, threshold wind velocity, and grain size distribution) were estimated for the imagery. Estimates of nutrient concentration on Saharan/Sahelian dust were used to estimate nutrient emissions. The results highlight patterns of dust emission from sources in North Africa and are compared with modeled and observed sources in the literature.

Ballantine, J. A.; Okin, G. S.; Roberts, D. A.

2003-12-01

369

Polarimetry of cosmic sources of hard gamma-ray emission  

NASA Astrophysics Data System (ADS)

The possibility of the polarimetry of cosmic sources of hard gamma-ray emission using telescopes containing spark chambers, based on the dependence of the anisotropy of the azimuthal distribution of the planes of e(+ or -) pairs on the degree of linear polarization, is discussed. An estimate is made of the photon statistics required for the measurement of polarization and it is concluded that such measurement is already feasible at the level of sensitivity of the Gamma-1 and GRO telescopes now being developed.

Kozlenkov, A. A.; Mitrofanov, I. G.

1985-10-01

370

Acoustic emission from single point machining: Part 1, Source mechanism  

SciTech Connect

Acoustic emission (AE) was monitored during single point, continuous machining of 4340 steel and Ti-6A1-4V as a function of heat treatment. Heat treatments which increase the strength of 4340 steel increase the amount of AE produced during deformation, while heat treatments which increase the strength of Ti-6A1-4V decrease the amount of AE produced during deformation. Trends in rms AE level during machining with increasing strength were similar for both alloys, demonstrating that chip deformation is not a major source of AE in sigle point machining. The data suggest that sliding friction between the nose and/or flank of the tool and the newly machined surface is the primary source of AE.

Heiple, C.R.; Carpenter, S.H.; Armentrout, D.L.; McManigle, A.P.

1989-01-01

371

[Research advances on volatile organic compounds emission inventory of plants].  

PubMed

Reference to relative literatures in recent years, model building and calculation on volatile organic compound (VOC) emission inventory of plants were summarized in different spatial scales, the total annual VOC emission amounts from Vegetation in China are in the range from 12.4 Tg x a(-1) to 28.4 Tg x a(-1). For garden plants in Beijing, the annual VOC emissions are approximately 38 500 tons C in 2000. Furthermore, in order to determine reduction strategies for Beijing urban atmospheric major pollutants, the contribution of garden plant VOC emissions to the ozone and secondary organic aerosol (SOA) formation was presented, compared to garden plant in the same period, the largest contribution to ozone formation comes from aromatic hydrocarbons and olefin which are exhausted from anthropogenic activity, besides, the aromatic hydrocarbons exhausted from anthropogenic activity is also a main contribution source for the potential formation of SOA. In the meantime, it is suggested to focus on emission control of VOCs which are emitted from urban anthropogenic sources. PMID:24640923

Xie, Jun-Fei; Li, Yan-Ming

2013-12-01

372

Significance of the Development of VOC Sensors  

NASA Astrophysics Data System (ADS)

The environmental problems relevant to VOC, such as sick house syndrome and air pollution, have attracted attention more and more. Japanese government has recently set forth the measure to VOC by amendments to related codes and regulations. The measurement technology and sensors for hazardous chemical substances, formaldehyde, toluene and xylene, are important to control the VOC level. The development of VOC sensors is desired because it is possible to measure VOC concentration simply and quickly, which makes it possible to realize the constant self-management of VOC and to check the real time change of VOC level. Since the performance requirements to a VOC sensor depend much on the applications, it is necessary to figure out the required specifications before starting the development of target VOC sensors. High performance VOC sensors applicable to many application fields are required to construct a secure and safe society.

Matsubara, Ichiro; Itoh, Toshio; Murayama, Norimitsu

373

Evaluation of emission control strategies to reduce ozone pollution in the Paso del Norte region using a photochemical air quality modeling system  

NASA Astrophysics Data System (ADS)

Air pollution emissions control strategies to reduce ozone precursor pollutants are analyzed by applying a photochemical modeling system. Simulations of air quality conditions during an ozone episode which occurred in June, 2006 are undertaken by increasing or reducing area source emissions in Ciudad Juarez, Chihuahua, Mexico. Two air pollutants are primary drivers in the formation of tropospheric ozone. Oxides of nitrogen (NOx) and volatile organic compounds (VOC) undergo multiple chemical reactions under favorable meteorological conditions to form ozone, which is a secondary pollutant that irritates respiratory systems in sensitive individuals especially the elderly and young children. The U.S. Environmental Protection Agency established National Ambient Air Quality Standards (NAAQS) to limit ambient air pollutants such as ozone by establishing an 8-hour average concentration of 0.075 ppm as the threshold at which a violation of the standard occurs. Ozone forms primarily due reactions in the troposphere of NOx and VOC emissions generated primarily by anthropogenic sources in urban regions. Data from emissions inventories indicate area sources account for ˜15 of NOx and ˜45% of regional VOC emissions. Area sources include gasoline stations, automotive paint bodyshops and nonroad mobile sources. Multiplicity of air pollution emissions sources provides an opportunity to investigate and potentially implement air quality improvement strategies to reduce emissions which contribute to elevated ozone concentrations. A baseline modeling scenario was established using the CAMx photochemical air quality model from which a series of sensitivity analyses for evaluating air quality control strategies were conducted. Modifications to area source emissions were made by varying NOx and / or VOC emissions in the areas of particular interest. Model performance was assessed for each sensitivity analysis. Normalized bias (NB) and normalized error (NE) were used to identify variability of the PREDICTED to OBSERVED ozone concentrations of both BASELINE model and simulations with modified emissions assessed by the sensitivity analysis. All simulations were found to vary within acceptable ranges of these two criteria variables. Simulation results indicate ozone formation in the PdN region is VOC-limited. Under VOC-limited conditions, modifications to NOx emissions do not produce a marked increase or decrease in ozone concentrations. Modifications to VOC emissions generated the highest variability in ozone concentrations. Increasing VOC emissions by 75% produced results which minimized model bias and error when comparing PREDICTED and OBSERVED ozone concentrations. Increasing VOC emissions by 75% either alone or in combination with a 75% increase in NOx emissions generated PREDICTED ozone concentrations very near to OBSERVED ozone. By evaluating the changes in ambient ozone concentrations through photochemical modeling, air quality planners may identify the most efficient or effective VOC emissions control strategies for area sources. Among the strategies to achieve emissions reductions are installation of gasoline vapor recovery systems, replacing high-pressure low-volume surface coating paint spray guns with high-volume low-pressure spray paint guns, requiring emissions control booths for surface coating operations as well as undertaking solvent management practices, requiring the sale of low VOC paint solvents in the surface-coating industry, and requiring low-VOC solvents in the dry cleaning industry. Other strategies to reduce VOC emissions include initiating Eco-Driving strategies to reduce fuel consumption from mobile sources and minimize vehicle idling at the international ports of entry by reducing bridge wait times. This dissertation depicts a tool for evaluating impacts of emissions on regional air quality by addressing the highly unresolved fugitive emissions in the Paso del Norte region. It provides a protocol for decision makers to assess the effects of various emission control strategies in the region. Impacts of specific sourc

Valenzuela, Victor Hugo

374

Far-Infrared sources and diffuse emission in M31  

NASA Technical Reports Server (NTRS)

A study on the far-infrared (FIR) emission of M31 has been carried out with the High Resolution (HiRes) maps (approx. 1 min) derived from IRAS data. Sixty-eight FIR sources are detected in M31, which in general coincide with optical HII regions, and contribute 15, 23, 29, and 23 percent to the fluxes in 12, 25, 60, and 100 micron bands, respectively. The remaining diffuse emission, which dominates the FIR emission of M31, is studied using a dust heating model which utilizes the UV and optical photometry maps and the HI maps available in the literature. It is found that the global dust-to-gas ratio in M31 disk is 6.5 10(exp -3), very close to the dust-to-gas ratio in the solar neighborhood. There is a significant galactocentric gradient of the dust-to-HI-gas ratio, with an e-folding scale length of 9 kpc. The diffuse dust correlates tightly with the HI gas. The model indicates that the non-ionizing UV (913-4000A) radiation from massive and intermediate massive stars contributes only about 30 percent of the heating of the diffuse dust, while the optical-NIR (4000-9000A) radiation from the old stellar population is responsible for the most of the heating.

Xu, Cong; Helou, George

1994-01-01

375

Sources and emission of greenhouse gases in Danube Delta lakes.  

PubMed

Production of methane and carbon dioxide as well as methane concentrations in surface waters and emissions to the atmosphere were investigated in two flow-through lake complexes (Uzlina-Isac and Puiu-Rosu-Rosulet) in the Danube Delta during post-flood conditions in May and low water level in September 2006. Retained nutrients fueled primary production and remineralization of bioavailable organic matter. This led to an observable net release of methane, particularly in the lakes Uzlina, Puiu and Rosu in May. Input from the Danube River, from redbuds and benthic release contributed to CH(4) concentrations in surface waters. In addition to significant river input of CO(2), this trace gas was released via aerobic remineralization within the water column and in top sediments. Emission patterns of CO(2) widely overlapped with those of CH(4). Generally, greenhouse gas emissions peaked in the lake complex adjacent to the Danube River in May due to strong winds and decreased with increasing hydrological distance from the Danube River. Intense remineralization of organic matter in the Danube Delta lakes results in a net source of atmospheric greenhouse gases. PMID:19506929

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

2009-08-01

376

Modeling the H2O submillimeter emission in extragalactic sources  

NASA Astrophysics Data System (ADS)

Recent observational studies have shown that H2O emission at (rest) submillimeter wavelengths is ubiquitous in infrared galaxies, both in the local and in the early Universe, suggestive of far-infrared pumping of H2O by dust in warm regions. In this work, models are presented that show that (i) the highest-lying H2O lines (Eupper > 400 K) are formed in very warm (Tdust ? 90 K) regions and require high H2O columns (NH2O ? 3 × 1017 cm-2), while lower lying lines can be efficiently excited with Tdust ~ 45-75 K and NH2O ~ (0.5-2) × 1017 cm-2; (ii) significant collisional excitation of the lowest lying (Eupper < 200 K) levels, which enhances the overall LH2O-LIR ratios, is identified in sources where the ground-state para-H2O 111-000 line is detected in emission; (iii) the H2O-to-infrared (8-1000 ?m) luminosity ratio is expected to decrease with increasing Tdust for all lines with Eupper ? 300 K, as has recently been reported in a sample of LIRGs, but increases with Tdust for the highest lying H2O lines (Eupper > 400 K); (iv) we find theoretical upper limits for LH2O/LIR in warm environments, owing to H2O line saturation; (v) individual models are presented for two very different prototypical galaxies, the Seyfert 2 galaxy NGC 1068 and the nearest ultraluminous infrared galaxy Arp 220, showing that the excited submillimeter H2O emission is dominated by far-infrared pumping in both cases; (vi) the LH2O - LIR correlation previously reported in observational studies indicates depletion or exhaustion time scales, tdep = ?gas/ ?SFR, of ?12 Myr for star-forming sources where lines up to Eupper = 300 K are detected, in agreement with the values previously found for (U)LIRGs from HCN millimeter emission. We conclude that the submillimeter H2O line emission other than the para-H2O 111-000 transition is pumped primarily by far-infrared radiation, though some collisional pumping may contribute to the low-lying para-H2O 202-111 line, and that collisional pumping of the para-111 and ortho-212 levels enhances the radiative pumping of the higher lying levels. Appendix A is available in electronic form at http://www.aanda.org

González-Alfonso, E.; Fischer, J.; Aalto, S.; Falstad, N.

2014-07-01

377

Neutron-emission measurements at a white neutron source  

SciTech Connect

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

Haight, Robert C [Los Alamos National Laboratory

2010-01-01

378

A potential source of atmospheric sulfur from penguin colony emissions  

NASA Astrophysics Data System (ADS)

Samples of fresh penguin excrements and lake sediments composed of aged penguin excrements were collected on an Antarctic Peninsula island. Gases emitted from these samples were collected and analyzed for volatile organosulfur compounds. No dimethyl sulfide (DMS) was found. However, dimethyl trisulfide (DMTS), dimethyl tetrasulfide (DMTTS), and dimethyl pentasulfide (DMPS) were found among the numerous organic compounds emitted from fresh penguin droppings. These sulfur compounds account for as mush as 13.5% of the emitted gases, but they have not been reported previously in atmospheric gases and therefore may represent a hitherto undetected source of atmospheric sulfur. To evaluate the potential contribution of this non-DMS biogenic source to the atmospheric sulfur reservoir at high southern latitudes, measurements of various chemical species in aerosols at several coastal Antarctic locations were analyzed and compared. The locations include Zhongshan Station (China) and Dumont D'Urville (France) in east Antarctica. Tentative calculations based on assumptions of similar aerosol sources and composition at these locations show that in areas downwind from large penguin colonies up to 5.5 × 10-5 nmol m-3 sulfur may be attributed to penguin emissions on a per-penguin basis. Depending on the size of penguin population at a given location, sulfur from this non-DMS source may account for 5-15% of the total non-sea-salt (nss) sulfur in these areas. Such high contributions may significantly impact the atmospheric sulfur burden and alter the sulfur budget in the high southern latitudes.

Xie, Zhou-Qing; Sun, Li-Guang; Wang, Jian-Jun; Liu, Bai-Zhan

2002-11-01

379

40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?  

Code of Federal Regulations, 2010 CFR

...emission limitations must I meet for puncture sealant application affected sources? 63...Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63...emission limitations must I meet for puncture sealant application affected sources?...

2010-07-01

380

40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?  

Code of Federal Regulations, 2010 CFR

...emission limitations must I meet for puncture sealant application affected sources? 63...Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63...emission limitations must I meet for puncture sealant application affected sources?...

2009-07-01

381

40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?  

Code of Federal Regulations, 2013 CFR

...emission limitations must I meet for puncture sealant application affected sources? 63...Manufacturing Emission Limitations for Puncture Sealant Application Affected Sources § 63...emission limitations must I meet for puncture sealant application affected sources?...

2013-07-01

382

Mobile-source-emissions analysis for California. Volume 2. Final report, 1982-85  

Microsoft Academic Search

This report reviews mobile-source emissions from California vehicles and updates the analytical basis for mobile-source-emissions modelling. The research effort addresses the following issues among others: identifies the market penetration of emissions-control systems for model years 1975-1982 vehicles and projects the penetration of the systems to 1990; reviews 1975 forward in-use vehicle emissions data to evaluate the performance of individual emissions

R. Crawford; K. Duleep; R. Dulla; T. Austin; G. Rubenstein

1985-01-01

383

Mobile-source emissions analysis for California. Volume 1. Final report, 1982-85  

Microsoft Academic Search

This report, reviews mobile-source emissions from California vehicles and updates the analytical basis for mobile-source-emissions modelling. The research effort addresses the following issues, among others: Identifies the market penetration of emissions-control systems for model years 1975-1982 vehicles and projects the penetration of the systems to 1990; reviews 1975 forward in-use vehicle emissions data to evaluate the performance of individual emissions

R. Crawford; K. Duleep; R. Dulla; T. Austin; G. Rubenstein

1985-01-01

384

Particle number emissions and source signatures of an industrial facility.  

PubMed

The work presented was conducted within the scope of a larger study investigating impacts of the Stuart Oil Shale project, a facility operating to the north of the industrial city of Gladstone, Australia. The aims of the investigations were threefold: (a) the identification of the plant signatures in terms of particle size distributions in the submicrometer range (13-830 nm) through stack measurements, (b) exploring the applicability of these signatures in tracing the source contributions at locations of interest, at a distance from the plant, and (c) assessing the contribution of the plant to the total particle number concentration at locations of interest. The stack measurements conducted for three different conditions of plant operation showed that the particle size distributions were bimodal with average modal count median diameters (CMDs) of 24 (SD 4) and 52 (SD 9) nm. The average of all the particle size distributions recorded within the plant sector at a site located 4.5 km from the plant, over the sampling period when the plant was operating, also showed a bimodal distribution. The modal CMDs in this case were 27 and 50 nm, similar to those at the stack. This bimodal size distribution is distinct from the size distribution of the most common ambient anthropogenic emission source, which is vehicle emissions, and can be considered as a signature of this source. The average contribution of the plant (for plant sector winds) was estimated to be (10.0 +/- 3.8) x 10(2) particles cm(-3) and constituted approximately a 50% increase overthe local particle ambient concentration for plant sector winds. This increase in particle number concentration compared to the local background concentration, while high compared to the clean environment concentration, is not significant when compared to concentrations generally encountered in the urban environment of Brisbane. PMID:16509322

Morawska, L; Johnson, G R; He, C; Ayoko, G A; Lim, M C H; Swanson, C; Ristovski, Z D; Moore, M

2006-02-01

385

The MMT bag for emission source sampling: design and evaluation.  

PubMed

This paper presents the design and evaluation results for a metal-coated multilayer Tedlar (MMT) bag that was developed for the collection of source emissions. The applicability of the MMT bag was evaluated for a number of important greenhouse relevant gases: CO, CO2, CH4, N2O, and total hydrocarbons (THCs). The bag was tested for durability and stability for a range of concentrations of the tested compounds using both laboratory-prepared samples and real source samples. The results show that all tested compounds were more stable when stored in the MMT bag than when stored in a regular Tedlar bag. These compounds can be stored at room temperature for at least 3 months without significant changes in concentration. When properly packed, the MMT bag is durable and may be shipped by air. The MMT bag is lower in cost, lighter in weight, and easier to clean, and it requires less devices during the subsequent laboratory analysis compared with a stainless steel canister, which is often used to collect air and source samples. PMID:11218426

Fan, Z; Zhang, J; Fan, C W; Pennise, D M

2001-01-01

386

Identification of volatile hydrocarbons as mobile source tracers for fine-particulate organics  

SciTech Connect

Several volatile organic compounds (VOCs) have been identified as candidates for tracers of fine particulate carbon and Extractable Organic Matter (EOM) from mobile sources. The identification resulted from a multiple screening procedure in which the ambient concentrations of a candidate VOC were first required to have both a high correlation with ambient concentrations of fine particulate Pb, a well established tracer of mobile source emissions, and a low correlation with soil-corrected fine particle potassium (K'), a previously demonstrated tracer of woodsmoke, using measurements from an airshed in which these were the dominant sources. Each VOC surviving this screening was then substituted in place of Pb, and along with K', in multi-linear regression representations of the carbon and EOM data. Successful VOCs resulted in a multiple correlation coefficient (r{sup 2}) at least as good as with K' and Pb, and estimates of the woodsmoke and mobile source contributions virtually the same as with K' and Pb. The reasonableness of these VOCs as mobile source tracers was affirmed by considering what is known about the abundance of those VOCs in woodsmoke and mobile source emissions.

Zweidinger, R.B.; Stevens, R.K.; Lewis, C.W.; Westburg, H.

1990-01-01

387

Volatile organic compound sources for Southern Finland  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) have several sources, both biogenic and anthropogenic. Emissions of biogenic VOCs in a global scale are estimated to be an order of magnitude higher than anthropogenic ones. However, in densely populated areas and during winter time the anthropogenic VOC emissions dominate over the biogenic ones. The aim of this study was to clarify potential local sources and source areas of VOCs in different seasons. Diurnal behaviour in winter and spring were also compared at two different sites in Finland: SMEAR II and III (Station for Measuring Ecosystem - Atmosphere Relations). SMEAR II is a rural site located in Hyytiälä in Southern Finland 220 km North-West from Helsinki whereas SMEAR III is background urban site located 5 km from the downtown of Helsinki. The volume mixing ratios of VOCs were measured with a proton-transfer-reaction mass spectrometer (PTR-MS, Ionicon Analytik GmbH, Austria) during years 2006-2011. Other trace gases such as CO, NOXand SO2 were also measured in both sites and used for source analysis. Source areas for long term VOC measurements were investigated with trajectory analysis and sources for local and regional concentrations were determined by Unmix multivariate receptor model. Forest fires affect air quality and the biggest smoke plumes can be seen in satellite images and even hinder visibility in the plume areas. They provide temporally and spatially well-defined sources that can be used to verify source area estimates. During the measurement periods two different forest fire episodes with several hotspots, happened in Russia. Forest fires which showed up in these measurements were in 2006 near the border of Finland in Vyborg area and 2010 in Moscow area. Forest fire episodes were clearly observed in trajectory analysis for benzene, toluene and methanol and also CO and NOX. In addition to event sources continuous source areas were determined. Anthropogenic local sources seemed to be dominant during winter in both sites. However during spring biogenic influence increased. In addition to source analysis this behaviour was visible in enhanced diurnal cycles of VOCs (Patokoski et al., 2014, in press). We will present important sources and source areas for Southern Finland's concentrations. References: Patokoski, J., Ruuskanen, T.M., Hellén, H., Taipale, R., Grönholm, T., Kajos, M.K., Petäjä, T., Hakola, H., Kulmala, M. & Rinne, J., 2014. Winter to spring transition and diurnal variation of VOCs in Finland at an urban background site and a rural site. Boreal Env. Res. 19. In press.

Patokoski, Johanna; Ruuskanen, Taina M.; Kajos, Maija K.; Taipale, Risto; Rantala, Pekka; Aalto, Juho; Ryyppö, Timo; Hakola, Hannele; Rinne, Janne

2014-05-01

388

72 FR 74088 - National Emission Standards for Hazardous Air Pollutants for Area Sources: Electric Arc Furnace...  

Federal Register 2010, 2011, 2012, 2013

...Area Sources: Electric Arc Furnace Steelmaking Facilities; Final Rule Federal Register...Area Sources: Electric Arc Furnace Steelmaking Facilities AGENCY: Environmental Protection...emission standards for electric arc furnace steelmaking facilities that are area sources...

2007-12-28

389

BASELINE EMISSIONS FORECASTS FOR INDUSTRIAL NON-BOILER SOURCES  

EPA Science Inventory

The report gives regional air emission forecasts from three Process Model Projection Technique (PROMPT) runs. These estimates illustrate a range of possible future emissions. PROMPT, one of a number of National Acid Precipitation Assessment Program emission forecasting models, pr...

390

An overview of key emissions sources and ambient pollution characteristics from major cities in North America  

NASA Astrophysics Data System (ADS)

Many urban anthropogenic emission sources are difficult to characterize. They can be distributed across a spatial scale that precludes specific vector sampling. Others are difficult to identify a specific point of emissions. Novel emissions quantification methods, including fuel-based emission indicies and tracer flux ratio, are described and evaluated for a variety of urban pollution sources. These techniques can be used to quantify emissions for a large range of species including methane and carbon dioxide isotopes, formaldehyde and other toxic volatile organic carbon compounds, nitrogen oxides, carbon monoxide and black carbon particulate matter. Results from urban emissions source case-studies using a mobile laboratory either alone or in conjunction with tracer-release will be described. These include on road light duty and heavy duty vehicle emissions, in-use aircraft engine emissions at airports, and industrial emission sources.

Herndon, Scott; Fortner, Edward; Knighton, Berk; Floerchinger, Cody; Yacovitch, Tara; Roscioli, Rob; Zahniser, Mark; Nelson, David; Kolb, Charles; Zavala, Miguel; Molina, Luisa

2013-04-01

391

Ozone-initiated VOC and particle emissions from a cleaning agent and an air freshener: Risk assessment of acute airway effects.  

PubMed

Emissions of volatile organic compounds and ultrafine particles from a kitchen cleaning agent (cream) and plug-in air freshener were investigated in a 20m(3) walk-in climate chamber at low (~5ppb) and high ozone (~50ppb) test concentrations and 0.6 air exchange rate. The products emitted terpenes, inter alia limonene, dihydromyrcenol, geraniol, linalool, and glycol ethers. The ozone-initiated reaction products of these compounds were measured by air sampling on Tenax TA followed by thermal desorption GC-MS and air sampling on DNPH cartridges followed by liquid extraction and HPLC-UV analysis. Particle formation was monitored simultaneously. A number of oxygenated and poly-oxygenated reaction products were identified and risk assessed for acute airway effects: formaldehyde, acetaldehyde, acetone, 4-acetyl-1-methylcyclohexene, 6-methyl-5-heptene-2-one, 3-isopropenyl-6-oxo-heptanal, and 4-oxo-pentanal. These compounds generally increased initially at the high ozone concentration, while the terpenes decayed, concurrent with their consumption of ozone. At high ozone concentration, the plug-in air freshener resulted in concentrations of formaldehyde and 4-oxopentanal that may give rise to concern about sensory irritation and airflow limitation, respectively. At high ozone concentration, the kitchen cleaning agent and air freshener resulted in peak particle mass concentrations at 81?g/m(3) (8.5×10(5) #/cm(3)) and 24?g/m(3) (2.3×10(4) #/cm(3)), respectively. At low ozone concentration, the particle concentration peaked at 4?g/m(3) (1.0×10(5) #/cm(3)) after the application of the kitchen cleaning agent, while no increase was observed for the air freshener. The particles, in view of their organic composition and concentration, are not considered to cause acute airway effects. Testing under realistic conditions that mimic user pattern behavior is warranted to obtain acute and longer-term exposure data at realistic indoor ozone concentrations. PMID:24769411

Nørgaard, A W; Kudal, J D; Kofoed-Sørensen, V; Koponen, I K; Wolkoff, P

2014-07-01

392

[Study on the chemical compositions of VOCs emitted by cooking oils based on GC-MS].  

PubMed

Volatile organic compounds (VOCs) are key precursors of ozone and secondary organic aerosols in air, and the differences in the compositions of VOCs lead to their different contribution to atmospheric reaction. Cooking oil fume is one of the important sources of atmospheric VOCs, and its chemical compositions are distinc