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1

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

PubMed

Based on atmospheric volatile organic compounds (VOCs) pollution control requirements during the twelfth-five year plan and the current status of monitoring and management in the world, instrumental architecture and technical characteristics of continuous emission monitoring systems (CEMS) for VOCs emission from stationary sources are investigated and researched. Technological development needs of VOCs emission on-line monitoring techniques for stationary sources in China are proposed from the system sampling pretreatment technology and analytical measurement techniques. PMID:24640921

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

2013-12-01

2

[Anthropogenic VOC emission inventory and contribution from industrial sources in Ningbo].  

PubMed

Ningbo is an important industrial city in eastern China and is also the economic center in the south wing of the Yangtze River Delta (YRD). Recently, the VOC emissions from the local industrial activities and its effects on both the regional air quality and people's health were getting more and more attention. The anthropogenic VOC emission inventory of Ningbo in 2010 was established with collecting comprehensive activity data of anthropogenic sources. Furthermore, the industrial sectors were studied and the significant industries were identified with their contribution quantified. The result shows that the amount of anthropogenic VOC emission in Ningbo in 2010 is 176 kt. Industry, transportation and residential source are the most important VOC anthropogenic sources in Ningbo, which accounted for 62.0%, 17.2% and 15.5% respectively. Synthetic materials manufacturing and refined petroleum products manufacturing are the most important VOC emitting industries, which contributed 18.6% and 13.1% of the total VOC amount respectively, signifying the influence of these two industries to the VOC emissions in Ningbo. PMID:25244829

Li, Xuan; Wang, Xue-Song; Liu, Zhong; Wu, Liang; Weng, Yan-Bo; Hu, Jie

2014-07-01

3

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...

4

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

5

Anthropogenic sources of VOC in a football stadium: Assessing human emissions in the atmosphere  

NASA Astrophysics Data System (ADS)

Measurements of gas-phase volatile organic compounds (VOCs), aerosol composition, carbon dioxide (CO2), and ozone (O3) were made inside Coface Arena in Mainz, Germany (49°59?3?N, 8°13?27?E) during a football match on April 20 2012. The VOC measurements were performed with a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS). Observed VOCs could be classified into several distinct source categories including (1) human respiration/breath, (2) ozonolysis of skin oils, and (3) cigarette smoke/combustion. In this work, we present a detailed discussion on the scale and potential impacts of VOCs emitted as a result of these sources and their contributions on local and larger scales. Human emissions of VOCs have a negligible contribution to the global atmospheric budget (?1% or less) for all those quantified in this study. However, fluxes as high as 0.02 g m-2 h-1 and 2 × 10-4 g m-2 h-1, for ethanol and acetone respectively are observed, suggesting the potential for significant impact on local air chemistry and perhaps regional scales. This study suggests that even in outdoor environments, situations exist where VOCs emitted as a result of human presence and activity are an important component of local air chemistry.

Veres, Patrick R.; Faber, Peter; Drewnick, Frank; Lelieveld, Jos; Williams, Jonathan

2013-10-01

6

Short-chain oxygenated VOCs: Emission and uptake by plants and atmospheric sources, sinks, and concentrations  

Microsoft Academic Search

Emissions of volatile organic compounds (VOCs) have multiple atmospheric implications and play many roles in plant physiology and ecology. Among these VOCs, growing interest is being devoted to a group of short-chain oxygenated VOCs (oxVOCs). Technology improvements such as proton transfer reaction-mass spectrometry are facilitating the study of these hydrocarbons and new data regarding these compounds is continuously appearing. Here

Roger Seco; Josep Peñuelas; Iolanda Filella

2007-01-01

7

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

8

VOC Emissions From Decomposing Leaf Litter  

NASA Astrophysics Data System (ADS)

The emission of VOCs from the biosphere has a profound effect on the oxidative capacity of the troposphere. Most studies of the flux of reactive carbon from the biosphere have focused on BVOC emissions at leaf and canopy scales with relatively few studies investigating BVOC emissions from soils. Here we present results describing the emissions of a suite of BVOCs from different litter types under different levels of nitrogen availability. To investigate these effects, three biochemically distinct litter types (Deschampsia sp., Acomostylis sp., and Rhododendron sp.) were coarsely ground and incubated in the dark for two months under different nitrogen regimes at optimal conditions for microbial activity. We used proton transfer reaction mass spectrometry and an infrared gas analyzer (IRGA) to monitor BVOC emissions and CO2 production rates throughout the course of the investigation. When different leaf litter types decomposed, they released distinctly different types and quantities of VOCs. However, varying nitrogen availability caused the VOC signature from some litters to change dramatically. We suggest that decomposition of leaf litter could provide a substantive source of reactive carbon to the atmosphere at local and regional scales and hypothesize that nitrogen deposition may play a role in attenuating the release of some reactive species.

Brown, E. M.; Wilkinson, M. J.; Fierer, N.; Monson, R. K.

2007-12-01

9

Sources of Volatile Organic Compounds (VOCs) in the UAE  

NASA Astrophysics Data System (ADS)

The gas chromatography-flame ionization detection/mass spectrometry system has been used to identify major volatile organic compounds (VOCs) sources in the UAE (latitude 24.45N; longitude 54.22E). VOCs are emitted from an extensive number of sources in urban environments including fuel production, distribution, and consumption. Transport sources contribute a substantial portion of the VOC burden to the urban atmosphere in developed regions. UAE is located at the edge of the Persian Gulf and is highly affected by emissions from petrochemical industries in neighbouring Saudi Arabia, Qatar, and Iran. VOCs emerging from these industries can be transported to the UAE with jet streams. The analysis of the collected air samples at three locations in Sharjah, UAE during the autumn and winter seasons indicates the presence of more than 100 VOC species. The concentrations of these species vary in magnitudes but the most prominent are: acetylene, ethane, propane, butane, pentane, benzene, and toluene. The possible tracers for various emission sources have also been identified such as 2-methylpentane, 1, 3-butadiene and 2, 2-dimethlybutane for vehicle exhaust, the light hydrocarbons, namely n-butane, trans-2-butene, and n-pentane for gasoline vapor, and n-nonane, n-decane, and n-undecane for diesel vapor and asphalt application processes. As various emission sources are characterized by overlapping VOC species, the ratio of possible VOC tracers are used to quantify the contribution of different sources. Our aim in this paper is to explore and discuss possible impacts of transported emissions on the local VOC emission inventory from various sources for the UAE. This work is partially supported by Office of Development and Alumni Affairs at the American University of Sharjah, U.A.E.

Abbasi, Naveed; Majeed, Tariq; Iqbal, Mazhar; Riemer, Daniel; Apel, Eric; Lootah, Nadia

10

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...

11

Source contributions to ambient VOCs and CO at a rural site in eastern China  

Microsoft Academic Search

Ambient data on volatile organic compounds (VOCs) and carbon monoxide (CO) obtained at a rural site in eastern China are analyzed to investigate the nature of emission sources and their relative contributions to ambient concentrations. A principal component analysis (PCA) showed that vehicle emissions and biofuel burning, biomass burning and industrial emissions were the major sources of VOCs and CO

H. Guo; T. Wang; I. j. Simpson; D. r. Blake; X. m. Yu; Y. h. Kwok; Y. s. Li

2004-01-01

12

EVALUATION OF VOC EMISSIONS FROM HEATED ROOFING ASPHALT  

EPA Science Inventory

The report gives results of a short-term in-house project to characterize emissions from a simulated asphalt roofing kettle, performed at EPA/AEERL. ot asphalt surfacing and resurfacing has been identified as a possible significant source of volatile organic compound (VOC) emissi...

13

Modeling the Effects of VOC and NOx Emission Sources on Ozone Formation in Houston during the TexAQS 2000 Field Campaign  

SciTech Connect

A meteorological and chemical modeling system is used to determine the effect of ethene and propene point source emission rates on the magnitude and distribution of ozone in the vicinity of Houston. The model performance is evaluated using surface and airborne meteorological and chemical measurements made as part of the 2000 Texas Air Quality Study. A simulation that employed the reported mobile, area, biogenic, and point source emissions produced ozone mixing ratios as high as 120 ppb and distributions of nitrogen oxides that were similar to measurements at most locations, but the model underestimated ozone mixing ratios greater than 140 ppb that were located just downwind of petrochemical facilities. When the point source emission rates of ethene and propene were increased by a factor of 10, the simulated peak ozone levels were in better agreement with surface, aircraft, and lidar observations. The magnitude of the simulated ethene and olefin concentrations were in better agreement with canister samples aloft as well; however, there was still a large amount of scatter in the results. While the highest ozone mixing ratios were produced just downwind of large point source emissions of VOCs, sensitivity simulations also showed that reductions in anthropogenic emissions of NOx would be needed to reduce ozone mixing ratios over a larger area.

Jiang, Guangfeng; Fast, Jerome D.

2004-09-01

14

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

15

Implementation of VOC source reduction practices in a manufactured house and in school classrooms  

SciTech Connect

Detailed studies of a new manufactured house and four new industrialized relocatable school classrooms were conducted to determine the emission sources of formaldehyde and other VOCs and to identify and implement source reduction practices. Procedures were developed to generate VOC emission factors that allowed reasonably accurate predictions of indoor air VOC concentrations. Based on the identified sources of formaldehyde and other aldehydes, practices were developed to reduce the concentrations of these compounds in new house construction. An alternate ceiling panel reduced formaldehyde concentrations in the classrooms. Overall, the classrooms had relatively low VOC concentrations.

Hodgson, A.T.; Apte, M.G.; Shendell, D.G.; Beal, D.; McIlvaine, J.E.R.

2002-01-01

16

Wind tunnels vs. flux chambers: Area source emission measurements and the necessity for VOC and odour correction factors  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wind tunnels and flux chambers have been used to measure fluxes of volatile organic compounds (VOC), odour, and ammonia (NH3) with little regard to air velocity or sweep air flow rates. As a result, flux measurements have been highly variable and scientists have been in disagreement as to the better...

17

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.

18

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

19

Study of the effect of biogenic VOC emissions on regional ozone production and the implications for VOC or NO{sub x} control  

SciTech Connect

A key question for the development of air pollution control strategies is whether to reduce nitrogen oxides (NO{sub x}) or volatile organic compound (VOC) emissions. Significant levels of biogenic VOC emissions may greatly limit the effectiveness of VOC control strategies. Concerns have been raised because for many cities it has been suggested that biogenic emissions are a dominate source of VOCs. Biogenic emissions would be expected to contribute an even larger fraction of the VOC emissions on the regional scale than within urban areas. The authors used a new atmospheric chemistry mechanism, the Regional Atmospheric Chemistry Mechanism (RACM), to perform ozone reactivity calculations to investigate the effects of biogenic emissions on the production of photooxidants in the atmosphere. The results show that incremental reactivity of isoprene is about the same as xylene and that the incremental reactivities of d-limonene and a-pinene are near those of toluene.

Stockwell, W.R.; Kuhn, M. [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

1998-12-31

20

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

21

VOC Emission Control with the Brayton Cycle Pilot Plant Operations  

E-print Network

VOC EMISSION CONTROL WITH THE BRAYTON CYCLE PILOT PLANT OPERATIONS (Abstract Only) Joseph C. Enneking, NUCON International, Inc., Columbus, OH A mobile pilot plant capable of removing voe emissions from exhaust air streams was cooperatively...

Enneking, J. C.

22

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

23

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

24

VOC Emissions from Amazonian tree species: Investigation of primary emission at leaf level  

NASA Astrophysics Data System (ADS)

Vegetation is regarded as the major source of volatile organic compounds (VOCs) emitted to the atmosphere. Little information is currently available regarding emissions of VOCs from tropical tree species at leaf level. 14 tree species from the different environments of the Amazon basin, i.e.Terra firme, Várzea and Igapó, were screened for VOCs emission at leaf level with a branch enclosure system. Analysis of volatile organics was performed online by PTR-MS and offline by collection on adsorbent tubes and subsequent GC-FID and GC-MS analysis. Even though standard emission variability between individual of the same species was quite high in a few cases, we observed that six of the screened species emitted methanol, four isoprene, four monoterpenes and one acetone, independently from their original environment. Highest standard emissions, given based on leaf dry weight. were observed for isoprene (63-12 µg g-1 s-1) followed by monoterpenes (26-0.5 µg g-1 s-1), methanol (9.5-0.5µg g-1 s-1) and acetone (0.5-0.3µg g-1 s-1). The main monoterpene species emitted was ?-pinene followed by limonene, sabinene and ß-pinene, with variable emission patterns depending on the tree species. Light dependent VOC emission correlates very well with the Guenther algorithm 1995.

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

2009-04-01

25

Evaluation of VOC emissions from heated roofing asphalt. Final report  

SciTech Connect

The report gives results of a short-term in-house project to characterize emissions from a simulated asphalt roofing kettle, performed at EPA/AEERL. Hot asphalt surfacing and resurfacing has been identified as a possible significant source of volatile organic compound (VOC) emissions that may affect human health and contribute to the ozone non-attainment problem. The purpose of the study was to collect, identify, and semi-quantitate as many compounds as possible that are discharged during the open heating of roofing asphalt and relate them to the amount volatilized into the air. Types 1, 2, and 3 mopping grade asphalts were chosen for the study. They constitute more than 90% of roofing asphalt used. Samples of each type of asphalt were placed in a simulated roofing kettle, heated to predetermined temperatures, and sampled for volatile and semi-volatile organic emissions. Compounds identified during the study were alkanes, aromatics, a ketone, and an aldehyde.

Kariher, P.; Tufts, M.; Hamel, L.

1991-11-01

26

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

27

Reduce VOC Emissions from Manufacturing Processes  

Microsoft Academic Search

This paper provides insight of many aspects of reducing VOC approaches geared towards assembly and test factories. With the management supports to take environment excellence to the next level, the Chemical management team working together with factory floor employees has embarked on a journey and impressive results shown passion for environmental effort and poised to set benchmark as future factory

Tan Lin Sheng; M. Z. bin Shamsudin; Loh Chin Ling

2006-01-01

28

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

29

Compilation of a database on the composition of anthropogenic VOC emissions for atmospheric modeling in Europe  

NASA Astrophysics Data System (ADS)

To analyse and generate air pollution control strategies and policies, e.g. efficient abatement strategies or action plans that lead to a fulfilment of air quality aims, atmospheric dispersion models (CTMs) have to be used. These models include a chemical model, where the numerous volatile organic compounds (VOCs) species are lumped together in classes. On the other hand, emission inventories usually report only total non-methane VOC (NMVOC), but not a subdivision into these classes. Thus, VOC species profiles are needed that resolve total NMVOC emission data. The objective of this publication is to present the results of a compilation of VOC species profiles that dissolve total VOC into single-species profiles for all relevant anthropogenic emission source categories and the European situation. As in atmospheric dispersion models usually modules for generating biogenic emissions are directly included, only anthropogenic emissions are addressed. VOC species profiles for 87 emission source categories have been developed. The underlying data base can be used to generate the data for all chemical mechanisms. The species profiles have been generated using recent measurements and studies on VOC species resolution and thus represent the current state of knowledge in this area. The results can be used to create input data for atmospheric dispersion models in Europe. The profiles, especially those for solvent use, still show large uncertainties. There is still an enormous need for further measurements to achieve an improved species resolution. In addition, the solvent use directive and the DECOPAINT directive of the European Commission will result in a change of the composition of paints; more water-based and high-solid paints will be used; thus the species resolution will change drastically in the next years. Of course, the species resolution for combustion and production processes also requires further improvement.

Theloke, J.; Friedrich, R.

30

VOCs Emission Control in Industrial Pollution Source Using Plasma Technology Coupled with F-TiO2/?-Al2O3.  

PubMed

Abstract Volatile organic compounds (VOCs) effluents, which come from many industries, are triggering serious environmental problems. As an emerging technology, non-thermal plasma (NTP) technology is a potential technology for VOCs emission control. NTP coupled with F-TiO2/?-Al2O3 is used for toluene removal from a gaseous influent at normal temperature and atmospheric pressure. NTP is generated by dielectric barrier discharge, and F-TiO2/?-Al2O3 can be prepared by Sol-Gel method in the laboratory. In the experiment, the different packed materials were packed into the plasma reactor, including ?-Al2O3, TiO2/?-Al2O3 and F-TiO2/?-Al2O3. Through a series of characterization methods such as XRD, SEM and BET, the results show the particle size distribution of F-TiO2 is relatively smaller than that of TiO2, and the pore distribution of F-TiO2 is more uniformly distributed than that of TiO2. The relationship among toluene removal efficiency, and reactor input energy density, and the equivalent capacitances of air gap and dielectric barrier layer were investigated. The results show the synergistic technology non-thermal plasma with F-TiO2/?-Al2O3 resulted in greater enhancement of toluene removal efficiency and energy efficiency. Especially, when packing with F-TiO2/?-Al2O3 in NTP reactor, toluene removal efficiency reaches 99%, and higher. Based on data analysis of FT-IR, the experimental results show NTP reactor packed with F-TiO2/?-Al2O3 resulted in a better inhibition for byproducts formation effectively in the gas exhaust. PMID:25428439

Zhu, Tao; Xia, Ni; Li, Xiaoyang; Chen, Rui; He, Xianxian; Zhao, Wenjuan; Carr, Tim

2014-11-27

31

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

32

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...

33

Conjugate Mass Transfer Modeling for VOC Source and Sink Behavior of Porous Building Materials: When to Apply It?  

Microsoft Academic Search

Volatile organic compounds (VOC) are major indoor air pollutants. Physical models have been developed to predict VOC source (emission) and sink behavior (sorption) of building materials. They frequently adopt the conventional convection approach using a third-kind boundary condition. This conventional convection approach in conjunction with the commonly used Sherwood number correlation is based on the assumptions of constant wall concentration

Chang-Seo Lee; Fariborz Haghighat; Wahid Ghaly

2006-01-01

34

Contribution of traffic emissions to indoor airborne VOCs  

SciTech Connect

The contribution of nearby vehicle traffic to indoor airborne volatile organic compound levels and to personal exposures was examined to determine the importance of this source. Indoor and outdoor levels of selected VOCs, aldehydes, ketones, and ethanol were measured at 10 homes in Toronto, on sidewalks near the traffic source, indoors and in the backyards or balconies of apartments (outdoors). Concurrently, air exchange rates were measured at each home with a perfluorocarbon tracer method. All the residences were within 1 km of urban intersections with traffic counts of more than 20,000 vehicles per day. Average concentrations of hexane, 1,3-butadiene, toluene, benzene and propionaldehyde decreased in the order: street level > indoor > outdoor. These compounds occur in vehicle emissions, and the contribution of outdoor to indoor concentrations ranged from 24 to 88 % suggesting that traffic emissions contributed to indoor pollutant level through the process of air exchange. For other compounds different trends were observed. Indoors concentrations were greater than outdoors for ethylacetate, tetrachlorethane, pinene, limonene, 1,4-dichlorobenzene, naphthalene, formaldehyde, acetaldehyde and ethanol, for example. These compounds are common in consumer products, and the contribution of outdoor to indoor concentrations ranged from 2 to 44%. The differences in street and backyard (outdoor) concentrations for some compounds were large due to the presence of nearby vehicles at street level sampling sites, indicating that the impact of traffic on human exposures (pedestrians on sidewalks and occupants of vehicles) is potentially large, compared to the impact of general background urban air pollutants.

Otson, R.; Williams, D.T. [Health Canada, Ottawa, Ontario (Canada); Fellin, P. [Conor Pacific Environmental Ltd., Toronto, Ontario (Canada)

1998-12-31

35

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

Code of Federal Regulations, 2011 CFR

...false Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline...502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline...designed to collect the total organic compounds vapors displaced from tank trucks...

2011-07-01

36

Seasonal variations in VOC emission rates from gorse (Ulex europaeus)  

NASA Astrophysics Data System (ADS)

Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10-1300 ?mol m-2 s-1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7% of the total VOC (winter) to 97% (late summer). The monoterpenes ?-pinene, camphene, sabinene, ?-pinene, myrcene, limonene, trans-ocimene and ?-terpinene were also emitted, with ?-pinene being the dominant monoterpene during most the year. Trans-ocimene represented 33-66% of the total monoterpene during the hottest months from June to September. VOC emissions were found to be accurately predicted using existing algorithms. Standard (normalised) emission factors of VOCs from gorse were calculated using experimental parameters measured during the experiment and found to fluctuate with season, from 13.3±2.1 to 0.1±0.1 ?g C (g dwt)-1 h-1 in August 1995 and January 1995, respectively, for isoprene, and from 2.5±0.2 to 0.4±0.2 ?g C (g dwt)-1 h-1 in July and November 1995, respectively, for total monoterpenes. No simple clear relation was found to allow prediction of these seasonal variations with respect to temperature and light intensity. The effects of using inappropriate algorithms to derive VOC fluxes from gorse were assessed for isoprene and monoterpenes. Although on an annual basis the discrepancies are not significant, monthly estimation of isoprene were found to be overestimated by more than a factor of 50 during wintertime when the seasonality of emission factors is not considered.

Boissard, C.; Cao, X.-L.; Juan, C.-Y.; Hewitt, C. N.; Gallagher, M.

37

VOC Emissions from the Potential Biofuel Crop, Switchgrass  

NASA Astrophysics Data System (ADS)

Volatile organic compound (VOC) emission rates during the growth and simulated harvest phases were determined for three different cultivars of switchgrass (Panicum virgatum) using laboratory chamber measurements. Switchgrass is a candidate for use in second-generation (cellulosic) ethanol production and the acerage dedicated to its growth in the USA has already increased during the past decade. We estimate that the yearly emissions from switchgrass plantations, including both the growth and harvest phases, will be on the order of 3 kg C ha-1 methanol, 1 kg C ha-1 acetaldehyde, 1 kg C ha-1 acetone, 0.9 kg C ha-1 monoterpenes, 0.5 kg C ha-1 isoprene + 1-penten-3-ol, 0.2 kg C ha-1 hexenals, and 0.1 kg C ha-1 hexenols. These emission rates are lower than those expected from Eucalyptus or Poplar plantations, which are other potential biofuel crops and have significantly higher VOC emissions.

Graus, M.; Eller, A. S.; Fall, R.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; Qian, Y.; Sekimoto, K.; Monson, R. K.; Warneke, C.

2010-12-01

38

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

39

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 ...

40

Volatile organic compounds (VOCs) emission characteristics and control strategies for a petrochemical industrial area in middle Taiwan  

Microsoft Academic Search

This study investigated VOC emissions from the largest petrochemical industrial district in Taiwan and recommended some control measures to reduce VOC emissions. In addition to the petrochemical industry, the district encompasses a chemical and fiber industry, a plastics industry and a harbor, which together produce more than 95% of the VOC emissions in the area. The sequence of VOC emission

Chia-Hsien Yen; Jao-Jia Horng

2009-01-01

41

Is Carbonyl Sulfide a Tracer for the Emissions and Oxidation Products of Biogenic VOCs?  

NASA Astrophysics Data System (ADS)

Carbonyl sulfide (OCS) is a relatively inert sulfur species with mostly diffuse sources in the troposphere including emissions from the ocean and production from CS2. A large sink in the troposphere is the uptake by vegetation, governed by the same physical parameters as the uptake of carbon dioxide. As a result, there is recent interest in the use of carbonyl sulfide to study the carbon cycle. Here, we investigate whether the relative absence of OCS in an air mass is correlated with the presence of biogenic volatile organic compounds (VOCs) and their oxidation products, including organic aerosol and peroxyacyl nitrates (PANs). Airborne data obtained with the NOAA WP-3D during ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) in 2004 are used for this purpose. It will be shown that the lowest mixing ratios of OCS in the northeastern U.S. were observed in the continental boundary layer. High levels of biogenic VOCs were usually observed in parallel with low OCS. The opposite was not always true, caused by the difference in lifetime of biogenic VOCs and OCS, and possibly by a difference in vegetation types responsible for biogenic emissions and OCS uptake. The correlation between OCS and water-soluble organic carbon (WSOC), a subset of the organic carbon in secondary organic aerosol (SOA), was very weak in the boundary layer. These findings suggest that the variability in organic aerosol in the northeastern U.S. is only very weakly determined by biogenic VOC emissions.

de Gouw, J.; Warneke, C.; Weber, R.; Atlas, E.; Flocke, F.

2008-12-01

42

Estimates of ozone response to various combinations of NO(x) and VOC emission reductions in the eastern United States  

NASA Technical Reports Server (NTRS)

There is increasing recognition that controls on NO(x) emissions may be necessary, in addition to existing and future Volatile Organic Compounds (VOC) controls, for the abatement of ozone (O3) over portions of the United States. This study compares various combinations of anthropogenic NO(x) and VOC emission reductions through a series of model simulations. A total of 6 simulations were performed with the Regional Oxidant Model (ROM) for a 9-day period in July 1988. Each simulation reduced anthropogenic NO(x) and VOC emissions across-the-board by different amounts. Maximum O3 concentrations for the period were compared between the simulations. Comparison of the simulations suggests that: (1) NO(x) controls may be more effective than VOC controls in reducing peak O3 over most of the eastern United States; (2) VOC controls are most effective in urban areas having large sources of emissions; (3) NO(x) controls may increase O3 near large point sources; and (4) the benefit gained from increasing the amount of VOC controls may lessen as the amount of NO(x) control is increased. This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Roselle, Shawn J.; Schere, Kenneth L.; Chu, Shao-Hang

1994-01-01

43

Characteristics and source apportionment of VOCs measured in an industrial area of Nanjing, Yangtze River Delta, China  

NASA Astrophysics Data System (ADS)

Based on the data of volatile organic compounds (VOCs) collected continuously in the Nanjing industrial area, the VOCs temporal variability, photochemical reactivity, differences in tracer ratios, and source apportionment by principal component analysis/absolute principal component scores (PCA/APCS) were analyzed. The results showed that the total VOC concentration was 43.5 ppbv, which was 45.1% alkanes, 25.3% alkenes, 7.3% alkynes and 22.3% aromatics. There was an obvious seasonal variation in the of VOCs, with a maximum in summer and minimum in winter, as well as in the VOC components, with alkanes and alkynes highest in winter, alkenes highest in summer, and aromatics highest in spring. The VOCs exhibited significant diurnal variations, i.e. high at night and low during the day. The concentrations of nighttime VOCs were highest to lowest as follows: summer > autumn > spring > winter. By contrast, the concentrations of daytime VOCs were highest to lowest as follows: winter > summer > spring > autumn. The diurnal variation of the VOCs was the largest in autumn and the smallest in winter. The largest diurnal variation of alkanes and alkenes occurred in autumn, whereas the largest diurnal variation of aromatics and alkynes occurred in spring. Using the propylene-equivalent method, alkenes had the highest concentration, followed by aromatics and alkanes. The ratios of T/B, E/B and X/B were 1.2, 1.0 and 0.8, respectively, possibly due to the aging air mass. Based on the specific pollutant ratio method, the observation site was greatly affected by the surrounding industrial areas. The source analysis of the VOCs in the PCA/APCS mode showed that the sources consisted of industrial production sources, automobile emission sources, combustion sources, industrial production volatilization sources, solvent use sources and biogenic emission sources; in addition, there were seasonal variations. Overall, the sources related to industrial production activities accounted for 45-63% of the VOCs, followed by automobile emission sources, which accounted for 34-50%.

An, Junlin; Zhu, Bin; Wang, Honglei; Li, Yongyu; Lin, Xu; Yang, Hui

2014-11-01

44

Photochemical grid model implementation of VOC, NOx, and O3 source apportionment  

NASA Astrophysics Data System (ADS)

For the purposes of developing optimal emissions control strategies, efficient approaches are needed to identify the major sources or groups of sources that contribute to elevated ozone (O3) concentrations. Source based apportionment techniques implemented in photochemical grid models track sources through the physical and chemical processes important to the formation and transport of air pollutants. Photochemical model source apportionment has been used to estimate impacts of specific sources, groups of sources (sectors), sources in specific geographic areas, and stratospheric and lateral boundary inflow on O3. The implementation and application of a source apportionment technique for O3 and its precursors, nitrogen oxides (NOx) and volatile organic compounds (VOC), for the Community Multiscale Air Quality (CMAQ) model are described here. The Integrated Source Apportionment Method (ISAM) O3 approach is a hybrid of source apportionment and source sensitivity in that O3 production is attributed to precursor sources based on O3 formation regime (e.g., for a NOx-sensitive regime, O3 is apportioned to participating NOx emissions). This implementation is illustrated by tracking multiple emissions source sectors and lateral boundary inflow. NOx, VOC, and O3 attribution to tracked sectors in the application are consistent with spatial and temporal patterns of precursor emissions. The O3 ISAM implementation is further evaluated through comparisons of apportioned ambient concentrations and deposition amounts with those derived from brute force zero-out scenarios, with correlation coefficients ranging between 0.58 and 0.99 depending on specific combination of target species and tracked precursor emissions. Low correlation coefficients occur for chemical regimes that have strong non-linearity in O3 sensitivity, which demonstrates different functionalities between source apportionment and zero-out approaches, depending on whether sources of interest are either to be accounted for pollutant levels in a given scenario, or to be perturbed to invoke alternate scenarios.

Kwok, R. H. F.; Baker, K. R.; Napelenok, S. L.; Tonnesen, G. S.

2014-09-01

45

VOC source-receptor relationships in Houston during TexAQS-II  

NASA Astrophysics Data System (ADS)

During the TRAMP field campaign in August-September 2006, C 2-C 10 volatile organic compounds (VOCs) were measured continuously and online at the urban Moody Tower (MT) site. This dataset was compared to corresponding VOC data sets obtained at six sites located in the highly industrialized Houston Ship Channel area (HSC). Receptor modeling was performed by positive matrix factorization (PMF) at all sites. Conditional probability functions (CPF) were used to determine the origin of the polluted air masses in the Houston area. A subdivision into daytime and nighttime was carried out to discriminate photochemical influences. Eight main source categories of industrial, mobile, and biogenic emissions were identified at the urban receptor site, seven and six, respectively, at the different HSC sites. At MT natural gas/crude oil contributed most to the VOC mass (27.4%), followed by liquefied petroleum gas (16.7%), vehicular exhaust (15.3%), fuel evaporation (14.3%), and aromatics (13.4%). Also petrochemical sources from ethylene (4.7%) and propylene (3.6%) play an important role. A minor fraction of the VOC mass can be attributed to biogenic sources mainly from isoprene (4.4%). Based on PMF analyses of different wind sectors, the total VOC mass was estimated to be twofold at MT with wind directions from HSC compared to air from a typical urban sector, for petrochemical compounds more than threefold. Despite the strong impact of air masses influenced by industrial sources at HSC, still about a third of the total mass contributions at MT can be apportioned to other sources, mainly motor vehicles and aromatic solvents. The investigation of diurnal variation in combination with wind directional frequencies revealed the greatest HSC impact at the urban site during the morning, and the least during the evening.

Leuchner, Michael; Rappenglück, Bernhard

2010-10-01

46

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. PMID:24755686

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

2014-01-01

47

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline...Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline...collection system designed to collect the total organic compounds vapors displaced from tank...

2010-07-01

48

On the ozone production sensitivity and VOC emissions in the Nashville urban plume  

Microsoft Academic Search

Urban ozone is a hazard to human beings, crops, and forests. It is produced by NOx and VOC emissions, through photochemical processes. Control of ozone levels by reducing NOx or VOC emissions has been studied for decades with model simulations. However, due to the uncertainties in model simulations and the nonlinear characteristics of the photochemical processes, measurement data are used

Dongyang He

2000-01-01

49

EVALUATION OF POTENTIAL VOC SCREENING INSTRUMENTS  

EPA Science Inventory

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 several principles (i.e., fla...

50

Chlorinated volatile organic compounds (Cl-VOCs) in environment - sources, potential human health impacts, and current remediation technologies.  

PubMed

Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections. PMID:25016450

Huang, Binbin; Lei, Chao; Wei, Chaohai; Zeng, Guangming

2014-10-01

51

Seasonal variation of biogenic VOC emissions above a mixed hardwood forest in northern Michigan  

NASA Astrophysics Data System (ADS)

Fluxes of biogenic volatile organic compounds (VOCs) were measured at a hardwood forest in northern Michigan (UMBS, Prophet research site) over the course of the growing and senescing season. Methanol, acetaldehyde, acetone and isoprene were found to be the most abundant biogenic VOCs with maximum fluxes (mixing ratios in ppbv) of 2.0 mg m-2 h-1 (21.0), 1.0 mg m-2 h-1 (2.7), 1.6 mg m-2 h-1 (5.6) and 7.6 mg m-2 h-1 (6), respectively. The emission patterns show distinct seasonal changes and indicate a spring peak for methanol due to rapid leaf expansion and a fall peak for acetone and acetaldehyde most likely attributed to senescing and decaying biomass; isoprene emissions peaked as expected in the summer. We estimate potential source strengths of 8.9 Tg (C) y-1 methanol, 2.7 Tg (C) y-1 acetaldehyde and 7.0 Tg (C) y-1 acetone for deciduous temperate forests, which is a substantial contribution to the global atmospheric VOC budget.

Karl, T.; Guenther, A.; Spirig, C.; Hansel, A.; Fall, R.

2003-12-01

52

Biogenic VOCs emission inventory development of temperate grassland vegetation in Xilin River basin, Inner Mongolia, China.  

PubMed

Given the key role of biogenic volatile organic compounds (VOCs) to tropospheric chemistry and regional air quality, it is important to generate accurate VOCs emission inventories. However, only a less fraction of plant species, in temperate grassland of Inner Mongolia, has been characterized by quantitative measurements. A taxonomic methodology, which assigns VOCs measurements to unmeasured species, is an applicable and inexpensive alternation for extensive VOCs emission survey, although data are needed for additional plant families and genera to further validate the taxonomic approach in grassland vegetation. In this experiment, VOCs emission rates of 178 plant species were measured with a portable photoionization detector (PID). The results showed the most of genera and some families have consistent feature of their VOCs emission, especially for isoprene, and provide the basic premise of taxonomic methodology to develop VOCs emission inventories for temperate grassland. Then, the taxonomic methodology was introduced into assigning emission rate to other 96 species, which no measured emission rates available here. A systematical emission inventory of temperate grassland vegetation in Inner Mongolia was provided and further evidence that taxonomy relationship can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera to grassland vegetation. PMID:15900743

He, Nian-Peng; Han, Xing-Guo; Sun, Wei; Pan, Qing-Min

2004-01-01

53

Surface emission determination of volatile organic compounds (VOC) from a closed industrial waste landfill using a self-designed static flux chamber.  

PubMed

Closed landfills can be a source of VOC and odorous nuisances to their atmospheric surroundings. A self-designed cylindrical air flux chamber was used to measure VOC surface emissions in a closed industrial landfill located in Cerdanyola del Vallès, Catalonia, Spain. The two main objectives of the study were the evaluation of the performance of the chamber setup in typical measurement conditions and the determination of the emission rates of 60 different VOC from that industrial landfill, generating a valuable database that can be useful in future studies related to industrial landfill management. Triplicate samples were taken in five selected sampling points. VOC were sampled dynamically using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) connected to SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption coupled with a capillary gas chromatograph/mass spectrometry detector. The emission rates of sixty VOC were calculated for each sampling point in an effort to characterize surface emissions. To calculate average, minimum and maximum emission values for each VOC, the results were analyzed by three different methods: Global, Kriging and Tributary area. Global and Tributary area methodologies presented similar values, with total VOC emissions of 237 ± 48 and 222 ± 46 g day(-1), respectively; however, Kriging values were lower, 77 ± 17 gd ay(-1). The main contributors to the total emission rate were aldehydes (nonanal and decanal), acetic acid, ketones (acetone), aromatic hydrocarbons and alcohols. Most aromatic hydrocarbon (except benzene, naphthalene and methylnaphthalenes) and aldehyde emission rates exhibited strong correlations with the rest of VOC of their family, indicating a possible common source of these compounds. B:T ratio obtained from the emission rates of the studied landfill suggested that the factors that regulate aromatic hydrocarbon distributions in the landfill emissions are different from the ones from urban areas. Environmental conditions (atmospheric pressure, temperature and relative humidity) did not alter the pollutant emission fluxes. PMID:24176707

Gallego, E; Perales, J F; Roca, F J; Guardino, X

2014-02-01

54

PREDICTING THE EMISSIONS OF INDIVIDUAL VOCS FROM PETROLEUM-BASED INDOOR COATINGS  

EPA Science Inventory

The indoor use of petroleum-based coating materials may cause elevated volatile organic compound (VOC) concentrations. This paper presents a newly developed mass transfer model for estimating the emissions of individual VOCs from freshly coated surfaces. Results of a four-step va...

55

Analysis of UK and European NOx and VOC emission scenarios in the Defra model intercomparison exercise  

NASA Astrophysics Data System (ADS)

Simple emission scenarios have been implemented in eight United Kingdom air quality models with the aim of assessing how these models compared when addressing whether photochemical ozone formation in southern England was NOx- or VOC-sensitive and whether ozone precursor sources in the UK or in the Rest of Europe (RoE) were the most important during July 2006. The suite of models included three Eulerian-grid models (three implementations of one of these models), a Lagrangian atmospheric dispersion model and two moving box air parcel models. The assignments as to NOx- or VOC-sensitive and to UK- versus RoE-dominant, turned out to be highly variable and often contradictory between the individual models. However, when the assignments were filtered by model performance on each day, many of the contradictions could be eliminated. Nevertheless, no one model was found to be the 'best' model on all days, indicating that no single air quality model could currently be relied upon to inform policymakers robustly in terms of NOx- versus VOC-sensitivity and UK- versus RoE-dominance on each day. It is important to maintain a diversity in model approaches.

Derwent, Richard; Beevers, Sean; Chemel, Charles; Cooke, Sally; Francis, Xavier; Fraser, Andrea; Heal, Mathew R.; Kitwiroon, Nutthida; Lingard, Justin; Redington, Alison; Sokhi, Ranjeet; Vieno, Massimo

2014-09-01

56

Numerical modeling of VOC emissions from ozone reactions with human-worn clothing in an aircraft cabin  

E-print Network

compounds (VOCs) are indoor air pollutants with many adverse health effects for humans. Ozone reactions compounds (VOCs) are an important class of indoor air pollutants. Exposure to VOCs has been associated with human surfaces (skin, hair, and clothing) are an important source of VOCs in the indoor air, especially

Chen, Qingyan "Yan"

57

Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions  

NASA Astrophysics Data System (ADS)

Atmospheric volatile organic compounds (VOCs) are involved in ozone and aerosol generation, thus having implications for air quality and climate. VOCs and their emissions by vegetation also have important ecological roles as they can protect plants from stresses and act as communication cues between plants and between plants and animals. In spite of these key environmental and biological roles, the reports on seasonal and daily VOC mixing ratios in the literature for Mediterranean natural environments are scarce. We conducted seasonal (winter and summer) measurements of VOC mixing ratios in an elevated (720 m a.s.l.) holm oak Mediterranean forest site near the metropolitan area of Barcelona (NE Iberian peninsula). Methanol was the most abundant compound among all the VOCs measured in both seasons. While aromatic VOCs showed almost no seasonal variability, short-chain oxygenated VOCs presented higher mixing ratios in summer, presumably due to greater emission by vegetation and increased photochemistry, both enhanced by the high temperatures and solar radiation in summer. Isoprenoid VOCs showed the biggest seasonal change in mixing ratios: they increased by one order of magnitude in summer, as a result of the vegetation's greater physiological activity and emission rates. The maximum diurnal concentrations of ozone increased in summer too, most likely due to more intense photochemical activity and the higher levels of VOCs in the air. The daily variation of VOC mixing ratios was mainly governed by the wind regime of the mountain, as the majority of the VOC species analyzed followed a very similar diel cycle. Mountain and sea breezes that develop after sunrise advect polluted air masses to the mountain. These polluted air masses had previously passed over the urban and industrial areas surrounding the Barcelona metropolitan area, where they were enriched in NOx and in VOCs of biotic and abiotic origin. Moreover, these polluted air masses receive additional biogenic VOCs emitted in the local valley by the vegetation, thus enhancing O3 formation in this forested site. The only VOC species that showed a somewhat different daily pattern were monoterpenes because of their local biogenic emission. Isoprene also followed in part the daily pattern of monoterpenes, but only in summer when its biotic sources were stronger. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources.

Seco, R.; Peñuelas, J.; Filella, I.; Llusià, J.; Molowny-Horas, R.; Schallhart, S.; Metzger, A.; Müller, M.; Hansel, A.

2011-07-01

58

Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions  

NASA Astrophysics Data System (ADS)

Atmospheric volatile organic compounds (VOCs) are involved in ozone and aerosol generation, thus having implications for air quality and climate. VOCs and their emissions by vegetation also have important ecological roles as they can protect plants from stresses and act as communication cues between plants and between plants and animals. In spite of these key environmental and biological roles, the reports on seasonal and daily VOC mixing ratios in the literature for Mediterranean natural environments are scarce. We conducted seasonal (winter and summer) measurements of VOC mixing ratios in an elevated (720 m a.s.l.) holm oak Mediterranean forest site near the metropolitan area of Barcelona (NE Iberian Peninsula). Methanol was the most abundant compound among all the VOCs measured in both seasons. While aromatic VOCs showed almost no seasonal variability, short-chain oxygenated VOCs presented higher mixing ratios in summer, presumably due to greater emission by vegetation and increased photochemistry, both enhanced by the high temperatures and solar radiation in summer. Isoprenoid VOCs showed the biggest seasonal change in mixing ratios: they increased by one order of magnitude in summer, as a result of the vegetation's greater physiological activity and emission rates. The maximum diurnal concentrations of ozone increased in summer too, most likely due to more intense photochemical activity and the higher levels of VOCs in the air. The daily variation of VOC mixing ratios was mainly governed by the wind regime of the mountain, as the majority of the VOC species analyzed followed a very similar diel cycle. Mountain and sea breezes that develop after sunrise advect polluted air masses to the mountain. These polluted air masses had previously passed over the urban and industrial areas surrounding the Barcelona metropolitan area, where they were enriched in NOx and in VOCs of biotic and abiotic origin. Moreover, these polluted air masses receive additional biogenic VOCs emitted in the local valley by the vegetation, thus enhancing O3 formation in this forested site. The only VOC species that showed a somewhat different daily pattern were monoterpenes because of their local biogenic emission. Isoprene also followed in part the daily pattern of monoterpenes, but only in summer when its biotic sources were stronger. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources.

Seco, R.; Peñuelas, J.; Filella, I.; Llusià, J.; Molowny-Horas, R.; Schallhart, S.; Metzger, A.; Müller, M.; Hansel, A.

2011-12-01

59

Extended Research on Detection of Deception Using Volatile Organic Compound (VOC) Emissions  

SciTech Connect

A system that captures and analyzes volatile organic compound (VOC) emissions from skin surfaces may offer a viable alternative method to the polygraph instrument currently in use for detecting deception in U.S. government settings. Like the involuntary autonomic central nervous system response data gathered during polygraph testing, VOC emissions from the skin may provide data that can be used to detect stress caused by deception. Detecting VOCs, then, may present a noninvasive, non-intrusive method for observing, recording, and quantifying evidence of stress or emotional change.

Center for Human Reliability Studies

2006-06-01

60

VOC emissions, evolutions and contributions to SOA formation at a receptor site in eastern China  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) were measured by two online instruments (GC-FID/MS and PTR-MS) at a receptor site on Changdao Island (37.99° N, 120.70° E) in eastern China. Reaction with OH radical dominated chemical losses of most VOC species during the Changdao campaign. A photochemical-age-based parameterization method is used to calculate VOC emission ratios and to quantify the evolution of ambient VOCs. The calculated emission ratios of most hydrocarbons agree well with those obtained from emission inventory data, but determined emission ratios of oxygenated VOCs (OVOCs) are significantly higher than those from emission inventory data. The photochemical-age-based parameterization method is also used to investigate primary emissions and secondary formation of organic aerosol. The primary emission ratio of organic aerosol (OA) to CO is determined to be 14.9 ?g m-3 ppm-1, and secondary organic aeorosols (SOA) are produced at an enhancement ratio of 18.8 ?g m-3 ppm-1 to CO after 50 h of photochemical processing in the atmosphere. SOA formation is significantly higher than the level determined from VOC oxidation under both high-NOx (2.0 ?g m-3 ppm-1 CO) and low-NOx conditions (6.5 ?g m-3 ppm-1 CO). Polycyclic aromatic hydrocarbons (PAHs) and higher alkanes (> C10) account for as high as 17.4% of SOA formation, which suggests semi-volatile organic compounds (SVOCs) may be a large contributor to SOA formation during the Changdao campaign. The SOA formation potential of primary VOC emissions determined from field campaigns in Beijing and Pearl River Delta (PRD) is lower than the measured SOA levels reported in the two regions, indicating SOA formation is also beyond explainable by VOC oxidation in the two city clusters.

Yuan, B.; Hu, W. W.; Shao, M.; Wang, M.; Chen, W. T.; Lu, S. H.; Zeng, L. M.; Hu, M.

2013-09-01

61

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

62

Human health risk evaluation of selected VOC, SVOC and particulate emissions from scented candles.  

PubMed

Airborne compounds in the indoor environment arise from a wide variety of sources such as environmental tobacco smoke, heating and cooking, construction materials as well as outdoor sources. To understand the contribution of scented candles to the indoor load of airborne substances and particulate matter, candle emission testing was undertaken in environmentally controlled small and large emission chambers. Candle emission rates, calculated on the basis of measured chamber concentrations of volatile and semi-volatile organic compounds (VOC, SVOC) and particulate matter (PM), were used to predict their respective indoor air concentrations in a standard EU-based dwelling using 2 models: the widely accepted ConsExpo 1-box inhalation model and the recently developed RIFM 2-box indoor air dispersion model. The output from both models has been used to estimate more realistic consumer exposure concentrations of specific chemicals and PM in candle emissions. Potential consumer health risks associated with the candle emissions were characterized by comparing the exposure concentrations with existing indoor or ambient air quality guidelines or, where not existent, to established toxicity thresholds. On the basis of this investigation it was concluded that under normal conditions of use scented candles do not pose known health risks to the consumer. PMID:24582651

Petry, Thomas; Vitale, Danielle; Joachim, Fred J; Smith, Ben; Cruse, Lynn; Mascarenhas, Reuben; Schneider, Scott; Singal, Madhuri

2014-06-01

63

VOC emissions from residential combustion of Southern and mid-European woods  

NASA Astrophysics Data System (ADS)

Emissions of trace gases (carbon dioxide (CO2), carbon monoxide (CO), total hydrocarbons (THC)), and volatile organic compounds (VOCs) from combustion of European beech, Pyrenean oak and black poplar in a domestic woodstove and fireplace were studied. These woods are widely used as biofuel in residential combustion in Southern and mid-European countries. VOCs in the flue gases were collected in Tedlar bags, concentrated in sorbent tubes and analysed by thermal desorption-gas chromatography-flame ionisation detection (GC-FID). CO2 emissions ranged from 1415 ± 136 to 1879 ± 29 g kg-1 (dry basis). The highest emission factors for CO and THC, 115.8 ± 11.7 and 95.6 24.7 ± 6.3 g kg-1 (dry basis), respectively, were obtained during the combustion of black poplar in the fireplace. European beech presented the lowest CO and THC emission factors for both burning appliances. Significant differences in emissions of VOCs were observed among wood species burnt and combustion devices. In general the highest emission factors were obtained from the combustion of Pyrenean oak in the woodstove. Among the VOCs identified, benzene and related compounds were always the most abundant group, followed by oxygenated compounds and aliphatic hydrocarbons. The amount and the composition of emitted VOCs were strongly affected by the wood composition, the type of burning device and operating conditions. Emission data obtained in this work are useful for modelling the impact of residential wood combustion on air quality and tropospheric ozone formation.

Evtyugina, Margarita; Alves, Célia; Calvo, Ana; Nunes, Teresa; Tarelho, Luís; Duarte, Márcio; Prozil, Sónia O.; Evtuguin, Dmitry V.; Pio, Casimiro

2014-02-01

64

Cut-induced VOC emissions from agricultural grasslands.  

PubMed

The introduction of proton transfer reaction mass spectrometry (PTR-MS) for fast response measurements of volatile organic compounds (VOC) has enabled the use of eddy covariance methods to investigate VOC fluxes on the ecosystem scale. In this study PTR-MS flux measurements of VOC were performed over agricultural grassland during and after a cut event. Selected masses detected by the PTR-MS showed fluxes of methanol, acetaldehyde, and acetone. They were highest directly after cutting and during the hay drying phase. Simultaneously, significant fluxes of protonated ion masses 73, 81, and 83 were observed. Due to the limited identification of compounds with the PTR-MS technique, GC-MS and GC-FID-PTR-MS techniques were additionally applied. In this way, ion mass 73 could be identified as 2-butanone, mass 81 mainly as (Z)-3-hexenal, and mass 83 mainly as the sum of (Z)-3-hexenol and hexenyl acetates. Hexenal, hexenols, and the hexenyl acetates are mostly related to plant wounding during cutting. It was found that legume plants and forbs emit a higher number of different VOC species than graminoids. PMID:17538867

Davison, B; Brunner, A; Ammann, C; Spirig, C; Jocher, M; Neftel, A

2008-01-01

65

Comparing the VOC emissions between air-dried and heat-treated Scots pine wood  

NASA Astrophysics Data System (ADS)

The emissions of volatile organic compounds (VOCs) from air-dried Scots pine wood and from heat-treated Scots pine wood were compared with GC-MS analysis. Air-dried wood blocks released about 8 times more total VOCs than heat-treated (24 h at 230°C) ones. Terpenes were clearly the main compound group in the air-dried wood samples, whereas aldehydes and carboxylic acids and their esters dominated in the heat-treated wood samples. Only 14 compounds out of 41 identified individual compounds were found in both wood samples indicating considerable changes in VOC emission profile during heat-treatment process. Of individual compounds ?-pinene, 3-carene and hexanal were the most abundant ones in the air-dried wood. By contrast, in the heat-treated wood 2-furancarboxaldehyde, acetic acid and 2-propanone were the major compounds of VOC emission. Current emission results reveal that significant chemical changes have occurred, and volatile monoterpenes and other low-molecular-weight compounds have evaporated from the wood during the heat-treatment process when compared to air-dried wood. Major chemical changes detected in VOC emissions are explained by the thermal degradation and oxidation of main constituents in wood. The results suggest that if heat-treated wood is used in interior carpentry, emissions of monoterpenes are reduced compared to air-dried wood, but some irritating compounds might be released into indoor air.

Manninen, Anne-Marja; Pasanen, Pertti; Holopainen, Jarmo K.

66

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

67

Uptake and emission of VOCs near ground level below a mixed forest at Borden, Ontario  

NASA Astrophysics Data System (ADS)

Understanding of the atmosphere/forest canopy exchange of volatile organic compounds (VOCs) requires insight into deposition, emission, and chemical reactions of VOCs below the canopy. Currently, uncertainties in canopy processes, such as stomatal uptake, deposition, and sub-canopy chemistry, make it difficult to derive biogenic VOC emission inventories from canopy VOC concentration gradients. Between 18 July and 9 August 2009, VOCs were measured with proton-transfer-reaction mass spectrometry (PTR-MS) at 6 heights between 1 and 6 m beneath a 23 m high mixed-forest canopy. Measured VOCs included methanol, isoprene, acetone, methacrolein + methyl vinyl ketone (MACR+MVK), monoterpenes and sesquiterpenes. There are pronounced differences in the behaviour of isoprene and its by-products and that of the terpenes. Non-terpene fluxes are predominantly downward. In contrast, the terpene fluxes are significantly upward. A 1-dimensional canopy model was used to compare results to measurements with and without surface deposition of isoprene and MACR+MVK and emissions of monoterpenes and sesquiterpenes. Results suggest deposition velocities of 27 mm s-1 for isoprene and 12 mm s-1 for MACR+MVK and daytime surface emission rates of 63 ?g m-2 h-1 for monoterpenes. The modelled isoprene surface deposition is approximately 2% of the canopy top isoprene emissions and the modelled emissions of monoterpenes comprise approximately 15 to 27% of the canopy-top monoterpene emissions to the atmosphere. These results suggest that surface monoterpene emissions are significant for forest canopy/atmosphere exchange for this mixed forest location and surface uptake is relatively small for all the species measured in this study.

Gordon, M.; Vlasenko, A.; Staebler, R. M.; Stroud, C.; Makar, P. A.; Liggio, J.; Li, S.-M.; Brown, S.

2014-02-01

68

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...

69

VOC emissions, evolutions and contributions to SOA formation at a receptor site in Eastern China  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) were measured by two online instruments (GC-FID/MS and PTR-MS) at a receptor site on Changdao Island (37.99° N, 120.70° E) in eastern China. Reaction with OH radical dominated the chemical loss of most VOC species during the Changdao campaign. A photochemical age based parameterization method is used to calculate VOC emission ratios and to quantify the evolution of ambient VOCs. The calculated emission ratios of most hydrocarbons agree well with those obtained from emission inventory, but the emission ratios of oxygenated VOCs (OVOCs) are significantly lower than those from emission inventory. The photochemical age based parameterization method is also used to investigate primary emissions and secondary formation of organic aerosol. The primary emission ratio of OA to CO are determined to be 14.9 ?g m-3 ppm-1 and SOA are produced at an enhancement ratio of 18.8 ?g m-3 ppm-1 to CO after 50 h of photochemical processing in the atmosphere. SOA formation is significantly higher than the level determined from VOC oxidation under both high-NOx (2.0 ?g m-3 ppm-1 CO) and low-NOx condition (6.5 ?g m-3 ppm-1 CO). Polycyclic aromatic hydrocarbons (PAHs) and higher alkanes (>C10) account for as high as 17.4% of SOA formation, which suggests semi-volatile organic compounds (SVOCs) may be a large contributor to SOA formation during the Changdao campaign. SOA formation potential of primary VOC emissions determined from both field campaigns and emission inventory in China are lower than the measured SOA levels reported in Beijing and Pearl River Delta (PRD), indicating SOA formation cannot be explained by VOC oxidation in this regions. SOA budget in China is estimated to be 5.0-13.7 Tg yr-1, with a fraction of at least 2.7 Tg yr-1 from anthropogenic emissions, which are much higher than the previous estimates from regional models.

Yuan, B.; Hu, W. W.; Shao, M.; Wang, M.; Chen, W. T.; Lu, S. H.; Zeng, L. M.; Hu, M.

2013-03-01

70

Analysis of VOC emissions using PCA\\/APCS receptor model at city of Shanghai, China  

Microsoft Academic Search

Qualification of the sources of volatile organic compounds (VOCs) and their effects on city air pollution are crucial issues\\u000a to develop an effective air pollution control strategy in many polluted large cities of China. In this study, the VOC concentrations\\u000a measured in Shanghai, China from 2006 to 2008 are analyzed. A receptor model (PCA\\/APCS; Principal Component Analysis\\/Absolute\\u000a Principal Component Scores)

Fuhai Geng; Changjie Cai; Xuexi Tie; Qiong Yu; Junlin An; Li Peng; GuangQiang Zhou; Jianming Xu

2009-01-01

71

Control of VOC emissions from a flexographic printing facility using an industrial biotrickling filter.  

PubMed

The study of an industrial unit of biotrickling filter for the treatment of the exhaust gases of a flexographic facility was investigated over a 2-year period with the objective to meet the volatile organic compound (VOC) regulatory emission limits. Increasing the water flow rate from 2 to 40 m(3) h(-1) improved the performance of the process, meeting the VOC regulation when 40 m(3) h(-1) were used. An empty bed residence time (EBRT) of 36 s was used when the inlet air temperature was 18.7 °C, and an EBRT as low as 26 s was set when the inlet temperature was 26.8 °C. During this long-term operation, the pressure drop over the column of the bioreactor was completely controlled avoiding clogging problems and the system could perfectly handle the non-working periods without VOC emission, demonstrating its robustness and feasibility to treat the emission of the flexographic sector. PMID:22173423

Sempere, F; Martínez-Soria, V; Penya-Roja, J M; Waalkens, A; Gabaldón, C

2012-01-01

72

VOC emissions of smouldering combustion from Mediterranean wildfires in central Portugal  

NASA Astrophysics Data System (ADS)

Emissions of trace gases and C5-C10 volatile organic compounds (VOCs) from Mediterranean wildfires occurring in Portugal in summer 2010 were studied. Fire smoke was collected in Tedlar bags and analysed for CO, CO2, total hydrocarbons (THC) and VOCs. The CO, CO2 and THC emission factors (EFs) were 206 ± 79, 1377 ± 142 and 8.1 ± 9 g kg-1 biomass burned (dry basis), respectively. VOC emissions from Mediterranean wildfires were reported for the first time. Aromatic hydrocarbons were major components of the identified VOC emissions. Among them, benzene and toluene were dominant compounds with EFs averaging 0.747 ± 0.303 and 0.567 ± 0.422 g kg-1 biomass burned (dry basis), respectively. Considerable amounts of oxygenated organic volatile compounds (OVOCs) and isoprenoids were detected. 2-Furaldehyde and hexanal were the most abundant measured OVOCs with EFs of 0.337 ± 0.259 and 0.088 ± 0.039 g kg-1 biomass burned (dry basis), respectively. The isoprenoid emissions were dominated by isoprene (EF = 0.207 ± 0.195 g kg-1 dry biomass burned) and ?-pinene (EF = 0.112 ± 0.093 g kg-1 dry biomass burned). Emission data obtained in this work are useful for validating and improving emission inventories, as well for carrying out modelling studies to assess the effects of vegetation fires on air pollution and tropospheric chemistry.

Evtyugina, Margarita; Calvo, Ana Isabel; Nunes, Teresa; Alves, Célia; Fernandes, Ana Patrícia; Tarelho, Luís; Vicente, Ana; Pio, Casimiro

2013-01-01

73

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

NASA Astrophysics Data System (ADS)

Emission inventories defining regional and global biogenic volatile organic compounds (VOC) emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects). The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. 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 the most dominant compound emitted followed by monoterpenes, methanol and acetone. The average loss rates of VOC carbon in relation to the net CO2 assimilation were found below 4% and indicating normal unstressed plant behavior. Most of the Mediterranean species emitted a large variety of monoterpenes, whereas only five tropical species were identified as monoterpene emitters exhibiting a quite conservative emission pattern (?-pinene < limonene < sabinene < ß-pinene). Mediterranean plants showed additional emissions of sesquiterpenes. In the case of Amazonian plants no sesquiterpenes were detected. However, missing of sesquiterpenes may also be due to a lack of sensitivity of the measuring systems. Furthermore, our screening activities cover only 1% of tree species of such tropical areas as estimated based on recent biodiversity reports. Methanol emissions, an indicator of growth, were found to be 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.

2013-09-01

74

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...

75

Constraints on the sources and impacts of volatile organic compounds (VOCs) over North America from tall tower measurements  

NASA Astrophysics Data System (ADS)

This dissertation presents the first-ever in-situ tall tower measurements of volatile organic compound (VOC) concentrations. The data span August 2009 through July 2012, and provide new constraints on seasonal and long-term controls on VOC sources and their atmospheric effects. The 200 m sampling height provides a large-scale footprint, while the tall tower location, near the intersection of the main North American ecosystems and at times downwind of the Twin Cities, affords information on natural emissions from some of the most important US landscapes as well as on anthropogenic sources. I interpret the dataset using an atmospheric chemical transport model (GEOS-Chem CTM), with a focus on several key atmospheric VOCs. This dissertation finds that current models underestimate methanol emission rates for younger versus older leaves. This biased seasonality means that the photochemical role for methanol early in the growing season is presently underestimated. A Bayesian inverse analysis of the tall tower observations reveals that the prior estimate of North American anthropogenic acetone sources (based on the US EPA's NEI05 inventory) is accurate to within 20%. However, biogenic acetone emissions from broadleaf trees, shrubs, and herbaceous plants are presently underestimated (˜37%), while emissions from needleleaf trees plus secondary production from biogenic precursors are overestimated by a similar amount (˜40%). Model-measurement comparisons imply that isoprene emissions in the immediate vicinity of the tall tower are accurately captured by the MEGANv2.1 biogenic inventory, but that larger-scale regional emissions are underestimated, reflecting the heterogeneous land cover in this transitional landscape. Isoprene emissions play a key role in seasonal shifts between VOC-limited chemistry in the spring and fall and NOx-limited or transitional chemistry in the summer. A Bayesian inverse analysis based on the tall tower measurements suggests that: i) the RETRO global emission inventory significantly overestimates (> two-fold) US C6-C8 aromatic emissions; ii) the US EPA's NEI08 inventory likewise overestimates the toluene flux by a factor of 3, partly reflecting a bias in the estimated non-road emissions; and iii) total annual emissions of benzene and C8 aromatics in the EPA's NEI08 are accurate to within the analysis uncertainty, but with some seasonal biases for on-road emissions.

Hu, Lu

76

Evaluation of non-enteric sources of non-methane volatile organic compound (NMVOC) emissions from dairies  

NASA Astrophysics Data System (ADS)

Dairies are believed to be a major source of volatile organic compounds (VOC) in Central California, but few studies have characterized VOC emissions from these facilities. In this work, samples were collected from six sources of VOCs (Silage, Total Mixed Rations, Lagoons, Flushing Lanes, Open Lots and Bedding) at six dairies in Central California during 2006-2007 using emission isolation flux chambers and polished stainless steel canisters. Samples were analyzed by gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. Forty-eight VOCs were identified and quantified in the samples, including alcohols, carbonyls, alkanes and aromatics. Silage and Total Mixed Rations are the dominant sources of VOCs tested, with ethanol as the major VOC present. Emissions from the remaining sources are two to three orders of magnitude smaller, with carbonyls and aromatics as the main components. The data suggest that animal feed rather than animal waste are the main source of non-enteric VOC emissions from dairies.

Chung, Myeong Y.; Beene, Matt; Ashkan, Shawn; Krauter, Charles; Hasson, Alam S.

2010-02-01

77

The influence of CO{sub 2} concentrations on VOC emissions from soybeans  

SciTech Connect

A flow-through plant enclosure method was used to collect VOCs emitted from soybeans (Glycine max) grown at the Biological Sciences Center at the Desert Research Institute. Samples of leaf emissions were collected on Tenax-Carbosieve cartridges and analyzed by gas chromatography-mass spectrometry at the Organic Analytical Laboratory at DRI. Samples of VOCs were also collected in 6 liter stainless steel canisters and analyzed by gas chromatography-flame ionization detection. Among the VOCs observed were {alpha}-pinene and limonene. The soybeans were grown in two plant enclosures with carbon dioxide levels of 250 ppm and 1,000 ppm. Leaf emissions from soybeans grown in the enclosure with 250 ppm CO{sub 2} showed higher concentrations of {alpha}-pinene, while limonene concentrations remained unchanged.

Goliff, W.S.; Sims, D.A.; Zielinska, B.

1999-07-01

78

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...

79

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...

80

CAPSTONE REPORT ON THE DEVELOPMENT OF A STANDARD TEST METHOD FOR VOC EMISSIONS FROM INTERIOR LATEX AND ALKYD PAINTS  

EPA Science Inventory

This document provides a detailed report on the small-chamber test method developed by EPA/NRMRL for characterizing volatile organic compound (VOC) emissions from interior latex and alkyd paints. Current knowledge about VOC, including hazardous air pollutant, emissions fr...

81

CAPSTONE REPORT ON THE DEVELOPMENT OF A STANDARD TEST METHOD FOR VOC EMISSIONS FROM INTERIOR LATEX PAINT AND ALKYD PAINTS  

EPA Science Inventory

The report gives details of a small-chamber test method developed by the EPA for characterizing volatile organic compound (VOC) emissions from interior latex and alkyd paints. Current knowledge about VOC, including hazardous air pollutant, emissions from interior paints generated...

82

CAPSTONE REPORT ON THE DEVELOPMENT OF A STANDARD TEST METHOD FOR VOC EMISSIONS FROM INTERIOR LATEX AND ALKYD PAINTS  

EPA Science Inventory

The report gives details of a small-chamber test method, developed by EPA for characterizing volatile organic compound (VOC) emissions from inte-rior latex and alkyd paints. Current knowledge about VOC, including haz-ardous air pollutant, emissions from in-terior paints generated...

83

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

84

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

85

Microbial community related to volatile organic compound (VOC) emission in household biowaste  

Microsoft Academic Search

Summary Malodorous emissions and potentially pathogenic microorganisms which develop during domestic organic waste collection are not only a nuisance but may also pose health risks. The aim of the present study was to determine whether the presence of spe- cific microorganisms in biowastes is directly related to the composition of the emitted volatile organic compounds (VOCs). The succession of microbial

Sabine Mayrhofer; Tomas Mikoviny; Sebastian Waldhuber; Andreas O. Wagner; Gerd Innerebner; Ingrid H. Franke-Whittle; Tilman D. Märk; Armin Hansel; Heribert Insam

2006-01-01

86

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...

87

SUMMARY OF JOINT DOD, EPA RESEARCH TO CONTROL VOC AND TOXIC EMISSIONS  

EPA Science Inventory

The paper summarizes the results of joint projects conducted during last 6 years by the Department of Defense and EPA to control volatile organic compounds (VOCs) and toxic emissions. ajor emphasis has been on product coating and metal finishing: (1) paint stripping using plastic...

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

New observations of VOC emissions and concentrations in, above, and around the Central Valley of California  

NASA Astrophysics Data System (ADS)

Large portions of the Central Valley of California are out of compliance with current state and federal air quality standards for ozone and particulate matter, and the relative importance of biogenic and anthropogenic VOC emissions to their photochemical production in this region remains uncertain. In 2009-2011 multiple measurement campaigns were completed investigating the VOC emission inventory and concentration distributions. In 2009 BVOC emissions from more than 20 species of major agricultural crops in California were measured in a greenhouse using branch enclosures by both PTRMS and in-situ GC. Overall, crops were found to emit low amounts of BVOC compared to the natural forests surrounding the valley. Crops mainly emitted methanol and terpenes, with a broad array of other species emitted at lower levels, and all the measured crops showed negligible emissions of isoprene. Navel oranges were the largest crop BVOC emitters measured so a full year of flux measurements were made in an orange grove near Visalia in 2010 by eddy covariance(EC)-PTRMS with two multi-week periods of concentration measurements by hourly in-situ GC, and one month of high mass resolution flux measurements by EC-PTR-TOF-MS. The dominant BVOC emissions from the orange grove were methanol and terpenes, followed by acetone, acetaldehyde, and a low level of emissions for many other species. In 2011 aircraft eddy covariance measurements of BVOC fluxes were made by EC-PTRMS covering a large area of California as part of the California Airborne Bvoc Emission Research in Natural Ecosystem Transects (CABERNET) campaign aimed at improving BVOC emission models on regional scales, mainly profiling BVOC emissions from oak woodlands surrounding the Central Valley. In 2010, hourly in-situ VOC measurements were made via in-situ GC in Bakersfield, CA as part of the CalNex experiment. Additionally, in-situ measurements of fresh motor vehicle exhaust were made in Oakland's Caldecott tunnel. Measurements by in-situ GC included more than 200 anthropogenic and biogenic VOCs with a wide range of volatilities (up to 17 carbon atoms in size) and various functional groups (e.g. aldehydes, ketones, alcohols, halogens, sulfur, & nitrogen). Finally, in 2011 vertical profiles of VOC were made at 5 heights on a communication tower at Walnut Grove (~20 miles south of Sacramento) from 30' to 1550' by PTRMS. Results from all of these studies combined provide a novel overview of the distribution of VOC emissions and concentrations in, around, and above the Central Valley of California.

Goldstein, A. H.; Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Ormeno, E.; Holzinger, R.; Misztal, P. K.; Karl, T. R.; Guenther, A. B.; Fischer, M. L.; Harley, R. A.; Karlik, J. F.

2011-12-01

90

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

PubMed

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. PMID:24348524

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

2011-01-20

91

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

92

Impacts of simulated herbivory on VOC emission profiles from coniferous plants  

NASA Astrophysics Data System (ADS)

The largest global source of volatile organic compounds (VOCs) in the atmosphere is from biogenic emissions. Plant stressors associated with a changing environment can alter both the quantity and composition of the compounds that are emitted. This study investigated the effects of one global change stressor, increased herbivory, on plant emissions from five different coniferous species: bristlecone pine (Pinus aristata), blue spruce (Picea pungens), western redcedar (Thuja plicata), grand fir (Abies grandis), and Douglas-fir (Pseudotsugas menziesii). Herbivory was simulated in the laboratory via exogenous application of methyl jasmonate, an herbivory proxy. Gas-phase species were measured continuously with a gas chromatograph coupled to a mass spectrometer and flame ionization detector (GC-MS-FID). Stress responses varied between the different plant types and even between experiments using the same set of saplings. The compounds most frequently impacted by the stress treatment were alpha-pinene, beta-pinene, 1,8-cineol, beta-myrcene, terpinolene, limonene, and the cymene isomers. Individual compounds within a single experiment often exhibited a different response to the treatment from one another.

Faiola, C. L.; Jobson, B. T.; VanReken, T. M.

2014-09-01

93

Quantifying VOC emissions from polymers: A case study  

SciTech Connect

Evaluating residual volatile organic compound emissions emanating from low-density polyethylene can pose significant challenges. These challenges include quantifying emissions from: (a) multiple process lines with different operating conditions; (b) several different comonomers; (c) variations of comonomer content in each grade; and (d) over 120 grades of LDPE. This presentation is a Case Study outlining a project to develop grade-specific emission data for low-density polyethylene pellets. This study included extensive laboratory analyses and required the development of a relational database to compile analytical results, calculate the mean concentration and standard deviation, and generate emissions reports.

Schulze, J.K.; Qasem, J.S.; Snoddy, R. [C-K Associates, Inc., Baton Rouge, LA (United States)

1996-12-31

94

Controlling VOC and air toxic emissions from aircraft refinishing facilities -- a new approach  

SciTech Connect

Over the next two years, aircraft refinishing facilities will face stringent emission reduction/pollution prevention requirements mandated by the aerospace NESHAP regulation; compliance with these requirements will necessarily entail extensive process adjustments and even facility modifications for the installation of add-on air toxic and VOC emission controls. This paper presents the innovative approach that Hill Air Force Base is exploring for one of the C-130 aircraft hangars to achieve cost effective regulatory compliance, yet maintain operational flexibility and accommodate the high facility throughput schedule demanded by their target production levels. The approach encompasses two separate technological innovations: (1) Retrofit the existing aircraft hangar to accommodate recirculation, which will reduce the process exhaust flow rate up to 90%. (2) Vent the hangar exhaust to an intermediate concentrator system where the organics released from the hangar are collected. The concentrator is an integral part of the overall system design because it generates a relatively constant VOC feed rate into the biofilter. This is particularly crucial to the Hill Air Force Base application due to the intermittent nature of the hangar operation. The concentrator provides an even VOC inlet profile for optimal biofilter operation. (3) The VOCs collected by the concentrator are slowly released over time to a biofilter that is optimally designed to control emissions from aerospace coating operations. The cost savings provided by recirculation coupled with an intermediate concentrator system is realized directly; the exhaust flow vented to the biofilter control device is reduced by nearly 99% from 350,000 cfm to less than 5,000. This represents a reduction in VOC emission control system installation costs from >$6,000,000 to < $2,000,000.

Ayer, J. [Air Quality Specialists, Inc., Newport Beach, CA (United States); Wander, J. [AFRL/MLQE, Tyndall AFB, FL (United States). Armstrong Lab.

1998-12-31

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

Uptake and emission of VOCs near ground level below a mixed forest at Borden, Ontario  

NASA Astrophysics Data System (ADS)

Understanding of the atmosphere/forest canopy exchange of volatile organic compounds (VOCs) requires insight into the deposition, emission, and chemical reactions of VOCs below the canopy. Between 18 July and 9 August 2009, VOCs were measured with proton-transfer-reaction mass spectrometry (PTR-MS) at six heights between 1 and 6 m beneath a 23 m high mixed-forest canopy. Measured VOCs included methanol, isoprene, acetone, methacrolein and methyl vinyl ketone (MACR + MVK), monoterpenes, and sesquiterpenes. There are pronounced differences in the behaviour of isoprene and its by-products and that of the terpenes. Non-terpene mixing ratios increase with height, suggesting predominantly downward fluxes. In contrast, the terpene mixing ratios decrease with height, suggesting upward fluxes. A 1-D canopy model was used to compare results to measurements with and without surface deposition of isoprene and MACR + MVK and emissions of monoterpenes and sesquiterpenes. Results suggest deposition velocities of 2.7 mm s-1 for isoprene and 1.2 mm s-1 for MACR + MVK and daytime surface emission rates of 63 ?g m-2 h-1 for monoterpenes. The modelled isoprene surface deposition is approximately 2% of the canopy-top isoprene emissions and the modelled emissions of monoterpenes comprise approximately 15 to 27% of the canopy-top monoterpene emissions to the atmosphere. These results suggest that surface monoterpene emissions are significant for forest canopy/atmosphere exchange for this mixed-forest location and surface uptake is relatively small for all the species measured in this study.

Gordon, M.; Vlasenko, A.; Staebler, R. M.; Stroud, C.; Makar, P. A.; Liggio, J.; Li, S.-M.; Brown, S.

2014-09-01

97

VOC PREVENTION OPTIONS FOR SURFACE COATING  

EPA Science Inventory

The paper discusses some of the volatile organic compound (VOC) prevention options for surface coating. Most small surface coating industries are considered to be stationary area sources. Although stationary area sources may account for as much as 50% of national VOC emissions, t...

98

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

99

Challenges in using flux chambers to measure ammonia and VOC emissions from open feedlot pen surfaces and retention ponds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Few methodologies currently available to estimate ammonia and volatile organic compound (VOC) emissions from livestock operations have been adequately validated for accuracy. Flow-through flux chambers and wind tunnels are sometimes used; however, ammonia and VOC flux from pen or pond surfaces are a...

100

A Novel New Approach to VOC and HAP Emission Control  

E-print Network

of real estate. Non-thermal VOHAP (Volatile Organic Hazardous Air Pollutant) emission control devices require additional maintenance. They also require the replacement of costly consumables such as activated carbon or they use large amounts of energy...

McGinness, M.

101

Characterization of VOC Emissions from Various Components of Dairy Farming and their effect on San Joaquin Valley Air Quality  

NASA Astrophysics Data System (ADS)

The San Joaquin Valley Air Basin in Central California is classified by the U.S. Environmental Protection Agency (EPA) as a serious non-attainment area for health-based eight-hour federal ozone (smog) standard (1). In August 2005, the San Joaquin Valley Air Pollution Control District issued a report identifying dairies as a main source of Volatile Organic Compounds (VOCs) and fine particulate matter in the valley (2). Among these compounds, we have found that ethanol, methanol, acetone and acetaldehyde are produced in major quantities throughout the San Joaquin valley as by-products of yeast fermentation of silage and photochemical oxidation. These oxygenates, especially ethanol, play an important role in ozone (O3) formation within the valley. Three different types of sampling protocols were employed in order to determine the degree of enhancement of the four oxygenates in the valley air shed, as well as to determine their sources, emission profiles and emission rates. An assessment of the emissions of these oxygenates in the valley was achieved using data obtained on low altitude flights through the valley and from ground level samples collected thoughout the valley. The photochemical production of ozone was calculated for each of the four oxygenates and approximately one hundred other quantified VOCs. Based on the Maximum Incremental Reactivity (MIR) scale and concentrations of each oxygenate in the atmosphere, as much as 20% of O3 production in the valley is from ethanol and its photochemical by-product acetaldehyde. Our findings suggest that improvement to the valley air quality may be obtained by focusing on instituting new silage containment practices and regulations. 1. Lindberg, J. "Analysis of the San Joaquin Valley 2007 Ozone Plan." State of California Air Resources Board. Final Draft Staff Report. 5/30/2007. 2. Crow, D., executive director/APCO. "Air Pollution Control Officer's Determination of VOC Emisison Factors for Dairies." San Joaquin Valley Air Pollution Control District. Aug. 1st 2005.

Yang, M. M.; Meinardi, S.; Krauter, C.; Blake, D.

2008-12-01

102

GLOBAL INVENTORY OF VOLATILE ORGANIC COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES  

EPA Science Inventory

The paper discusses the development of a global inventory of anthropogenic volatile organic compound (VOC) emissions. t includes VOC estimates for seven classes of VOCs: paraffins, olefins, aromatics (benzene, toluene, xylene), formaldehyde, other aldehydes, other aromatics, and ...

103

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

104

Application of horizontal spiral coil heat exchanger for volatile organic compounds (VOC) emission control.  

PubMed

The petroleum products have wide range of volatility and are required to be stored in bulk. The evaporation losses are significant and it is a economic as well as environmental concern, since evaporative losses of petroleum products cause increased VOC in ambient air. Control of these losses poses a major problem for the storage tank designers. Ever rising cost of petroleum products further adds to the gravity of the problem. Condensation is one of the technologies for reducing volatile organic compounds emissions. Condensation is effected by condenser, which is basically a heat exchanger and the heat exchanger configuration plays an important role. The horizontal spiral coil heat exchanger is a promising configuration that finds an application in VOC control. This paper attempts to understand underlying causes of emissions and analyse the option of horizontal spiral coil heat exchanger as vent condenser. PMID:25508332

Deshpande, P M; Dawande, S D

2013-04-01

105

Application of horizontal spiral coil heat exchanger for volatile organic compounds (VOC) emission control.  

PubMed

The petroleum products have wide range of volatility and are required to be stored in bulk. The evaporation losses are significant and it is a economic as well as environmental concern, since evaporative losses of petroleum products cause increased VOC in ambient air. Control of these losses poses a major problem for the storage tank designers. Ever rising cost of petroleum products further adds to the gravity of the problem. Condensation is one of the technologies for reducing volatile organic compounds emissions. Condensation is effected by condenser, which is basically a heat exchanger and the heat exchanger configuration plays an important role. The horizontal spiral coil heat exchanger is a promising configuration that finds an application in VOC control. This paper attempts to understand underlying causes of emissions and analyse the option of horizontal spiral coil heat exchanger as vent condenser. PMID:25464701

Deshpande, P M; Dawande, S D

2013-04-01

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

Source Contributions to VOC's to Ozone Formation in Southeast Texas Using a Source-oriented Air Quality Model  

E-print Network

Houston-Galveston-Brazoria area is in severe non-attainment status for ozone compliance. Source-oriented mechanistic modeling was used to determine the major sources of VOCs that contributes to ozone formation during the Texas Air Quality Study (Tex...

Krishnan, Anupama

2011-08-08

108

Dynamic relationship between the VOC emissions from a Scots pine stem and the tree water relations  

NASA Astrophysics Data System (ADS)

The stems of coniferous trees contain huge storages of oleoresin. The composition of oleoresin depends on e.g. tree species, age, provenance, health status, and environmental conditions. Oleoresin is under pressure in the extensive network of resin ducts in wood and needles. It flows out from a mechanically damaged site to protect the tree by sealing the wounded site. Once in contact with air, volatile parts of oleoresin evaporate, and the residual compounds harden to make a solid protective seal over damaged tissues. The hardening time of the resin depends on evaporation rate of the volatiles which in turn depends on temperature. The storage is also toxic to herbivores and attracts predators that restrict the herbivore damage. Despite abundant knowledge on emissions of volatile isoprenoids from foliage, very little is known about their emissions from woody plant parts. We set up an experiment to measure emissions of isoprene and monoterpenes as well as two oxygenated VOCs, methanol and acetone, from a Scots pine (Pinus sylvestris) stem and branches. The measurements were started in early April and continued until mid-June, 2012. Simultaneously, we measured the dynamics of whole stem and xylem diameter changes, stem sap flow rate and foliage transpiration rate. These measurements were used to estimate A) pressure changes inside the living stem tissue and the water conducting xylem, B) the refilling of stem water stores after winter dehydration (the ratio of sap flow at the stem base to water loss by foliage), and C) the increase in tree water transport capacity (the ratio of maximum daily sap flow rate to the diurnal variation in xylem pressure) during spring due to winter embolism refilling and/or the temperature dependent root water uptake capacity. The results show that already very early in spring, significant VOC emissions from pine stem can be detected, and that they exhibit a diurnal cycle similar to that of ambient temperature. During the highest emission period a sudden decrease in stem diameter was observed, which we hypothesize could either indicate a decrease in the pressure of living cells in connection with stem VOC emissions, or result mechanically from exudation of oleoresin from the stem. We also found that the stem water stores and xylem water transport capacity increased during periods of VOC emissions, which indicates xylem embolism refilling during times of VOC emissions. A qualitative difference was found between VOC emissions from pine stem and thick branches, the stem emissions containing more sesquiterpenes. Most of the tree biomass is in the lower part of the stem, and as stem tissues are lacking green photosynthesizing tissue the emissions are supposed to be related to damage. Our results show that emissions from tree stems are connected to the tree water relations and that they are important during the period when the foliage still is rather inactive.

Vanhatalo, Anni; Chan, Tommy; Aalto, Juho; Kolari, Pasi; Rissanen, Kaisa; Hakola, Hannele; Hölttä, Teemu; Bäck, Jaana

2013-04-01

109

The Amazonian Floodplains, an ecotype with challenging questions on volatile organic compound (VOC) emissions  

NASA Astrophysics Data System (ADS)

Volatile organic compound (VOC) emissions are affected by a variety of biotic and abiotic factors such as light intensity, temperature, CO2 and drought. Another factor usually overlooked but very important for the tropical rainforest in Amazonia is regular flooding. According to recent estimates, the total Amazonian floodplain area easily ranges up to 700,000 km^2, including whitewater river floodplains (várzea) blackwater regions (igapó) and further clearwater regions. Regarding the total Amazonian wetlands the area sums up to more than 2.000.000 km^2, i.e. 30% of Amazonia. To survive the flooding periods causing anoxic conditions for the root system of up to several months, vegetation has developed several morphological, anatomical and physiological strategies. One is to switch over the root metabolism to fermentation, thus producing ethanol as one of the main products. Ethanol is a toxic metabolite which is transported into the leaves by the transpiration stream. From there it can either be directly emitted into the atmosphere, or can be re-metabolized to acetaldehyde and/or acetate. All of these compounds are volatile enough to be partly released into the atmosphere. We observed emissions of ethanol, acetaldehyde and acetic acid under root anoxia. Furthermore, plant stress induced by flooding also affected leaf primary physiological processes as well as other VOC emissions such as the release of isoprenoids and other volatiles. For example, Hevea spruceana could be identified as a monoterpene emitting tree species behaving differently upon anoxia depending on the origin, with increasing emissions of the species from igapó and decreasing with the corresponding species from várzea. Contrasting such short term inundations, studies of VOC emissions under long term conditions (2-3 months) did not confirm the ethanol/acetaldehyde emissions, whereas emissions of other VOC species decreased considerably. These results demonstrate that the transfer of our knowledge based on short-term experiments is risky being transferred to an ecotype which is governed under natural conditions by long term flooding. Furthermore, contrasting such experiments with usually young trees (saplings or a few years old) nothing is known about the emission behavior of adult trees under field conditions.

Kesselmeier, J.

2012-12-01

110

BTEX and other VOC emissions from a natural gas amine treater. Topical report, February 1996  

SciTech Connect

The report presents the results of a laboratory and field study conducted under Gas Research Institute (GRI) sponsorship to measure the pickup and distribution of benzene, toluene, ethylbenzene, and xylene (BTEX) and other volatile organic compounds (VOC) to the various internal process and emssion streams in a commercial amine treater used to remove acid gas compounds (primarily hydrogen sulfide and carbon dioxide) from natural gas. A laboratory study was conducted to evaluate an analytical technique for quantifying in diethanolamine (DEA) solutions. The accuracy and precision of the technique as well a method detection limit study were carried out. In the field study, samples of the inlet natural gas, flash gas, and regenerator vent gas, lean amine, and rich amine from various locations downstream of the absorber were collected and analyzed. The results were used to determine regenerator vent emission rates and the distribution of BTEX and other VOC around the flash tank.

Skinner, F.D.; Reif, D.L.; Wilson, A.C.

1996-02-01

111

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

112

Long-term variations in natural, terrestrial VOC emissions: 1000-1990 AD  

NASA Astrophysics Data System (ADS)

Natural vegetation emits large amounts of volatile organic compounds (e.g. monoterpenes and isoprene) into the atmosphere. Estimates of the total global source of biogenic volatile organic compounds (BVOCs) in the past millennium range between 1050 and 1100 Tg yr-1 (Adams et al. 2001). BVOCs have multiple impacts on atmospheric chemistry, for example they are believed to affect ozone formation, decrease the oxidizing capacity of the troposphere and substantially alter the concentrations of tropospheric aerosol in continental regions (Seinfeld et al., 1998). Organic compounds constitute 20-90% of the submicron aerosol mass, depending on location. Most of this contribution is secondary, meaning that the emitted VOCs are oxidized in the atmosphere followed by gas-to-particle conversion of the oxidation products (Jimenez et al., 2009). BVOCs emitted by vegetation are the dominant source of secondary organic aerosol (SOA) in the atmosphere (Guenther et al., 1995). Estimates on the present-day organic aerosol budgets are improving rapidly, but it is unclear how the organic aerosol fraction has evolved in the past. Such information is, however, needed for accurate estimates on the climate forcing caused by aerosols. Understanding the factors that have governed BVOC emissions in the past is a prerequisite for completing this task. We evaluate the variability of global fluxes of isoprene, monoterpenes and sesquiterpenes over the last millennium using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) (Guenther et al., 2006). MEGAN estimates the emission activity of BVOCs using meteorological (Air temperature, solar radiation, soil moisture) and landcover (Plant Functional Types (PFTs) and Leaf Area Index (LAI)) inputs. The model is driven off-line using meteorological fields from existing Max Planck Institute Earth System Model (MPI-ESM) (Jungclaus et al. 2010) millennium simulations, and reconstructions of the global changes PFTs and LAI (Kaplan et al., 2010). We evaluate the long-term response of terrestrial BVOC emission activity to variations in land-use change and climatic factors, and find that compared to preindustrial times (1000-1800 A.D.), global isoprene emissions have decreased 8%, monoterpenes emissions have increased 10% and sesquiterpenes emissions have increased 15% during the time period 1950-1990 A.D.. The results suggest that the variation of isoprene emissions is governed by land-use changes, while monoterpenenes and sesquiterpenes variations are dominated by climate variability. Adams, J.M. (2001). Chemosphere - Global Change Science, 3, 73-91 J.H. Seinfeld and S. N. Pandis. (1998). Atmospheric Chemistry and Physics . Wiley, New York Jimenez, J. L. et al. (2009). Science, 326, 1525-1529 Kaplan, J. O. et al (2010). The Holocene 21(5), 775-791 Guenther, A. et al. (1995). J. Geophys. Res., 100, 8873-8892 Hoyle, C. R. et al. (2011). Atmos. Chem. Phys., 11, 321-343 A. Guenther et al. (2006). Atmospheric Chemistry and Physics, 6:3181-3210 J. H. Jungclaus et al. (2010). Climate of the Past, 6:723-737

Acosta, J. C.; Struthers, H.; Zorita, E.; Ekman, A. M.; Riipinen, I.

2012-12-01

113

A standard reference for chamber testing of material VOC emissions: Design principle and performance  

NASA Astrophysics Data System (ADS)

Environmental chambers are widely used to test formaldehyde and other volatile organic compound (VOC) emissions from indoor materials and furniture. However, there is a lack of a proven method to assess the precision of the test results of the chamber system. In this paper, we describe a new standard reference, LIFE (liquid-inner tube diffusion-film-emission), to address this problem. This reference has the following salient features: (1) Constant emission rate, with less than 3.0% change with an ambient airflow speed (>0.014 m/s) at furniture emission range (0.1-1.0 mg/m 3 in a 30 m 3 chamber with air change rate of 1/h) under standard chamber test conditions as specified by ISO 16000-9 (23 °C, 50% RH); (2) Long duration of emissions, on the order of 1000 h; (3) Easy to store, apply and maintain. The design principle and criteria of the LIFE reference are presented. An analytical model and dimensionless analysis were applied to optimize the factors influencing the emission rate, and experiments were conducted to validate the analytical results. In addition, the equivalent emission parameters of the reference, i.e., the initial emittable concentration, the diffusion coefficient and the partition coefficient, were determined through a three-parameter optimizing regression. This can then be used to check the reliability of a chamber method for testing these three parameters. The developed standard reference should prove useful for calibrating chamber systems for indoor material/furniture VOC emissions tests.

Wei, Wenjuan; Zhang, Yinping; Xiong, Jianyin; Li, Mu

2012-02-01

114

Spatial and seasonal variation and source apportionment of volatile organic compounds (VOCs) in a heavily industrialized region  

NASA Astrophysics Data System (ADS)

Source apportionment is generally applied to a time series of pollutant concentrations measured at a single site. However, in a complex airshed having multiple pollutant sources, it may be helpful to collect samples from several sites to ensure that some of them have low contributions from specific sources. Ambient air samples (n = 160) were collected by passive sampling during four seasons in 2009 and 2010 at forty different sites in Aliaga, Turkey to determine the spatial, seasonal variations and possible sources of volatile organic compounds (VOCs). Fifty-eight VOCs (?58VOC) were detected. ?58VOC concentrations ranged between 0.1 and 1770 ?g m-3 (avg ± SD, 67 ± 193 ?g m-3). Aliphatic hydrocarbons were generally predominant with a high percentage of contribution (31%-88%) at all sites. Aromatic VOCs were the second highest group (8-50%), followed by halogenated VOCs (1-24%) and oxygenated VOCs (0.04-5.9%). Highly variable spatial distribution of ambient VOC concentrations suggested that the major sources in this region were industrial plants. Generally, VOC concentrations were higher in summer than in winter probably due to increased volatilization from their sources at higher ambient temperatures. However, high atmospheric VOC concentrations were also observed in winter and fall near the petroleum refinery and petrochemical complex, probably due to the calm conditions and high atmospheric stability that is commonly encountered during the winter months in the area, restricting the dilution of pollutants. The newest version of EPA PMF (V5.0) (Positive Matrix Factorization) having the capability of handling multiple site data was used for source apportionment. Refinery and petroleum products, petrochemical industry, solvent use and industrial processes, and vehicle exhaust were the identified VOC sources in the study area, contributing 56%, 22%, 12%, and 10%, respectively to the ?58VOC concentrations. Carcinogenic risks due to lifetime exposure to seven VOCs were also estimated. Estimated risks were the highest for 1,2-dichloroethane, followed by benzene, chloroform, and carbon tetrachloride. Carcinogenic risks for trichloroethene, 1,1,2-trichloroethane, and bromoform were lower than the general acceptable risk level of 1.0 × 10-6. However, risks for 1,2-dichloroethane, benzene, chloroform, and carbon tetrachloride were substantially higher than the acceptable level. It was concluded that carcinogenic risks may reach considerably high levels for a significant portion of the population living in the study area.

Dumanoglu, Yetkin; Kara, Melik; Altiok, Hasan; Odabasi, Mustafa; Elbir, Tolga; Bayram, Abdurrahman

2014-12-01

115

Modelling VOC source impacts on high ozone episode days observed at a mountain summit in Hong Kong under the influence of mountain-valley breezes  

NASA Astrophysics Data System (ADS)

A top-down approach to evaluate high ozone (O3) formation, attributed to different emission sources, is developed for anti-cyclonic conditions in a region of Hong Kong influenced by meso-scale circulations. A near-explicit photochemical model coupled with the Master Chemical Mechanism (MCMv3.2) is used to investigate the chemical characteristics in the region. Important features have been enhanced in this model including the photolysis rates, simulated by the National Center for Atmospheric Research (NCAR) Tropospheric Ultraviolet and Visible (TUV) Radiation Model, as well as hourly variation of Volatile Organic Compound (VOC) concentration input from on-site sampling. In general, the combined model gives a reasonably good representation of high O3 levels in the region. The model successfully captured a multi-day O3 event in the autumn of 2010. Source apportionment via Positive Matrix Factorization (PMF) was carried out on the sampled VOC data, to determine the major sources in the region. Based on the outcomes of the PMF source apportionment, a sensitivity analysis using the developed photochemical model was conducted and used to estimate O3 reduction under different source removal regimes. Results indicate that vehicular emissions are the dominant VOC source contributing to O3 formation. This study has demonstrated a potentially efficient secondary pollutants control methodology, using a combined field measurements and modelling approach.

Lam, S. H. M.; Saunders, S. M.; Guo, H.; Ling, Z. H.; Jiang, F.; Wang, X. M.; Wang, T. J.

2013-12-01

116

Associations between immune function in yearling beef cattle and airborne emissions of sulfur dioxide, hydrogen sulfide, and VOCs from oil and natural gas facilities.  

PubMed

Researchers assessed the associations between airborne emissions from oil and gas field facilities and the structure and function of the immune system of yearling beef cattle in 27 herds during spring 2002. They evaluated the immune systems of these animals by enumerating B lymphocytes and T-lymphocyte subtypes (CD4, CD8, gammadelta, and WC1) in peripheral circulation and by measuring systemic antibody production in response to vaccination. Researchers prospectively measured exposure to sulfur dioxide, hydrogen sulfide, and volatile organic compounds (VOCs) by using air-quality data from passive monitors installed in pastures and wintering areas. They estimated the mean exposure of each animal over the 6-month period before the start of sample collection. The researchers used mixed models, which adjusted for clustering by herd and accounted for known risk factors, to examine potential associations between exposure to airborne sulfur dioxide, VOCs (measured as concentrations of benzene and toluene) and hydrogen sulfide, as well as proximity to emission sources (well-site density), and the immune system outcomes. Increasing exposure to VOCs measured as toluene was associated with significant CD4 T lymphocytopenia. The number of CD4 T lymphocytes was 30% lower in cattle exposed to VOCs measured as toluene in the highest quartile (> 0.823 microg/m3) than in cattle exposed in the lowest quartile (< 0.406 microg/m3). PMID:19179269

Bechtel, Daniel G; Waldner, Cheryl L; Wickstrom, Mark

2009-01-01

117

Pulsed Corona Plasma Technology for Treating VOC Emissions from Pulp Mills  

SciTech Connect

Under the DOE Office of Industrial Technologies Forest Products program various plasma technologies were evaluated under project FWP 49885 ''Experimental Assessment of Low-Temperature Plasma Technologies for Treating Volatile Organic Compound Emissions from Pulp Mills and Wood Products Plants''. The heterogeneous pulsed corona discharge was chosen as the best non-equilibrium plasma technology for control of the vent emissions from HVLC Brownstock Washers. The technology for removal of Volatile Organic Compounds (VOCs) from gas emissions with conditions typical of the exhausts of the paper industry by means of pulsed corona plasma techniques presented in this work. For the compounds of interest in this study (methanol, acetone, dimethyl sulfide and ? -pinene), high removal efficiencies were obtained with power levels competitive with the present technologies for the VOCs removal. Laboratory experiments were made using installation with the average power up to 20 W. Pilot plant prepared for on-site test has average plasma power up to 6.4 kW. The model of the Pilot Plant operation is presented.

Fridman, Alexander A.; Gutsol, Alexander; Kennedy, Lawrence A.; Saveliev, Alexei V.; Korobtsev, Sergey V.; Shiryaevsky, Valery L.; Medvedev, Dmitry

2004-07-28

118

Reduction of VOC emissions from metal dip coating applications -- Canam Steel Corporation Point of Rocks, MD case study  

SciTech Connect

The reduction of VOC emissions from metal dip coating applications is not an environmental constraint, it is an economic opportunity. This case study shows how the industry can reap economic benefits from VOC reductions while improving air quality. The Canam Steel Corporation plant located in Point of Rocks, MD operates dip tanks for primer application on fabricated steel joists and joist girders. This process is presently subject to a regulation that limits the paint VOC content to 3.5 pounds per gallon of coating less water. As a result of the high paint viscosity associated with that regulation, the paint thickness of the dipped steel is thicker than the customers` specifications. Most of the VOC emissions can therefore be associated with the excess of paint applied to the products rather than to the required thickness of the coating. The higher paint usage rate has more than environmental consequences, it increases the cost of the applied coating. The project is to reduce the paint usage by controlling the viscosity of the coating in the tank. Experimental results as well as actual mass balance calculations show that using a higher VOC content paint would reduce the overall VOC emissions. The author explained the project to the Maryland Department of the Environment (MDE) Air and Radiation Management Administration. First, the MDE agreed to develop a new RACT determination for fabricated steel dipping operations. The new regulation would limit the amount of VOC than can be emitted to dip coat a ton of fabricated steel. Second, the MDE agreed to allow experimentation of the higher VOC content paint as a pilot project for the new regulation. This paper demonstrates the need for a RACT determination specific to fabricated steel dipping operations.

Monfet, J.P. [Canam Manac Group, Inc., Boucherville, Quebec (Canada)

1997-12-31

119

Global Emissions of Terpenoid VOCs from Terrestrial Vegetation in the Last Millennium  

SciTech Connect

We investigated the millennial variability of global BVOC emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene and sesquiterpene and Lund-Potsdam-Jena General Ecosystem Simulator (LPJ8 GUESS), for isoprene and monoterpenes. We found the millennial trends of global isoprene emissions to be mostly affected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have signicant short term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr-1 (13% and 19% less than during during 1750-1850 and 1000- 15 1200, respectively) and LPJ-GUESS emissions were 323 TgC yr-1 (15% and 20% less than during 1750-1850 and 1000-1200, respectively). Monoterpene emissions were 89 TgC yr-1 (10% and 6% higher than during 1750-1850 and 1000-1200, respectively) in MEGAN, and 24 TgC yr-1 (2% higher and 5% 19 20 less than during 1750-1850 and 1000-1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr-1 (10% and 4% higher than during1750-1850 and 1000-1200, respectively). Although both models capture similar We investigated the millennial variability of global BVOC emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene and sesquiterpene and Lund-Potsdam-Jena General Ecosystem Simulator (LPJ8GUESS), for isoprene and monoterpenes. We found the millennial trends ofglobal isoprene emissions to be mostly a*ected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have signifcant short term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr-1 (13% and 19% less than during during 1750-1850 and 1000- 1200, respectively) and LPJ-GUESS emissions were 323 TgC yr-1 (15% and 16 17 20% less than during 1750-1850 and 1000-1200, respectively). Monoterpene emissions were 89 TgC yr-1 (10% and 6% higher than during 1750-1850 and 18 1000-1200, respectively) in MEGAN, and 24 TgC yr-1 (2% higher and 5% less than during 1750-1850 and 1000-1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr-1 (10% and 4% higher than during1750-1850 and 1000-1200, respectively). Although both models capture similar emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.

Acosta Navarro, J. C.; Smolander, S.; Struthers, H.; Zorita, E.; Ekman, A. M.; Kaplan, J. O.; Guenther, Alex B.; Arneth, A.; Riipinen, I.

2014-06-16

120

Global emissions of terpenoid VOCs from terrestrial vegetation in the last millennium  

NASA Astrophysics Data System (ADS)

We investigated the millennial variability (1000 A.D.-2000 A.D.) of global biogenic volatile organic compound (BVOC) emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene, and sesquiterpene, and Lund-Potsdam-Jena-General Ecosystem Simulator (LPJ-GUESS), for isoprene and monoterpenes. We found the millennial trends of global isoprene emissions to be mostly affected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission trends were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have significant short-term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr-1 (13% and 19% less than during 1750-1850 and 1000-1200, respectively), and LPJ-GUESS emissions were 323 TgC yr-1(15% and 20% less than during 1750-1850 and 1000-1200, respectively). Monoterpene emissions were 89 TgC yr-1(10% and 6% higher than during 1750-1850 and 1000-1200, respectively) in MEGAN, and 24 TgC yr-1 (2% higher and 5% less than during 1750-1850 and 1000-1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr-1(10% and 4% higher than during 1750-1850 and 1000-1200, respectively). Although both models capture similar emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.

Acosta Navarro, J. C.; Smolander, S.; Struthers, H.; Zorita, E.; Ekman, A. M. L.; Kaplan, J. O.; Guenther, A.; Arneth, A.; Riipinen, I.

2014-06-01

121

Light-duty vehicle PM and VOC speciated emissions at differing ambient temperatues with ethanol blend gasoline  

EPA Science Inventory

With the rise in the use of ethanol-blend gasoline in the U.S., interest is increasing in how these fuel blends affect PM and VOC emissions. EPA conducted a study characterizing emissions from two flex-fuel and one non-flex-fueled light-duty vehicles operated on a chassis dynamom...

122

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...

123

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

NASA Astrophysics Data System (ADS)

Silage, fermented cattle feed, has recently been identified as a significant source of volatile organic compounds (VOCs) to the atmosphere. A small number of studies have measured VOC emission from silage, but not enough is known about the processes involved to accurately quantify emission rates and identify practices that could reduce emissions. Through a literature review, we have focused on identifying the most important compounds emitted from corn silage (the most common type of silage in the US) and the sources of these compounds by quantifying their production and emission potential in silage and describing production pathways. We reviewed measurements of VOC emission from silage and assessed the importance of individual silage VOCs through a quantitative analysis of VOC concentrations within silage. Measurements of VOC emission from silage and VOCs present within silage indicated that alcohols generally make the largest contribution to emission from corn silage, in terms of mass emitted and potential ozone formation. Ethanol is the dominant alcohol in corn silage; excluding acids, it makes up more than half of the mean mass of VOCs present. Acids, primarily acetic acid, may be important when emission is high and all VOCs are nearly depleted by emission. Aldehydes and esters, which are more volatile than acids and alcohols, are important when exposure is short, limiting emission of more abundant but less volatile compounds. Variability in silage VOC concentrations is very high; for most alcohols and acids, tolerance intervals indicate that 25% of silages have concentrations a factor of two away from median values, and possibly much further. This observation suggests that management practices can significantly influence VOC concentrations. Variability also makes prediction of emissions difficult. The most important acids, alcohols, and aldehydes present in silage are probably produced by bacteria (and, in the case of ethanol, yeasts) during fermentation and storage of silage. Aldehydes may also be produced aerobically by spoilage microorganisms through the oxidation of alcohols. Abiotic reactions may be important for production of methanol and esters. Although silage additives appear to affect VOC production in individual studies, bacterial inoculants have not shown a consistent effect on ethanol, and effects on other VOCs have not been studied. Production of acetic acid is understood, and production could be minimized, but a decrease could lead to an increase in other, more volatile and more reactive, VOCs. Chemical additives designed for controlling yeasts and undesirable bacteria show promise for reducing ethanol production in corn silage. More work is needed to understand silage VOC production and emission from silage, including: additional measurements of VOC concentrations or production in silage of all types, and an exploration of the causes of variability; accurate on-farm measurements of VOC emission, including an assessment of the importance of individual ensiling stages and practices that could reduce emission of existing VOCs; and work on understanding the sources of silage VOCs and possible approaches for reducing production.

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

2013-10-01

124

A Survey of California Plant Species With a Portable VOC Analyzer for Biogenic Emission Inventory Development  

NASA Astrophysics Data System (ADS)

An accurate estimate of the magnitude of biogenic volatile organic compound (BVOC) emissions relative to anthropogenic VOC emissions in California's airsheds is critical for formulating effective strategies to reduce concentrations of fine particles, ozone, and other secondary air pollutants which affect human health and reduce yields of agricultural crops. However, California's natural landscapes contain more than 5800 listed species, and urban landscapes contain hundreds more. A taxonomic method has been proposed to assign BVOC emission rate measurements to unmeasured species, but data were needed for additional plant families and genera to further develop the taxonomic approach. Replicate samples of live foliage of more than 250 plant species were placed in plastic bags, in both light and darkened conditions, and the BVOC emissions measured with a calibrated portable analyzer unit (PAU), and categorized as low, medium or high. To validate the PAU approach we compared our PAU-measured BVOC emissions for approximately 60 plant species with published values based on gas chromatography (GC) and GC-mass spectrometry and found them to be well correlated. For approximately 200 plant species not previously measured, the PAU data indicated that plant taxonomy served as a useful method for characterizing the magnitude and nature of emissions (either light or dark, or both). The method employed was more suited for detecting isoprene emissions, due to their relatively higher magnitudes, than emissions of monoterpenes or oxygenated compounds. The results provide further evidence that plant taxonomy can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera.

Karlik, J. F.; Winer, A. M.

2001-12-01

125

Trends in the emissions of Volatile Organic Compounds (VOCs) from light-duty gasoline vehicles tested on chassis dynamometers in Southern California  

NASA Astrophysics Data System (ADS)

We present fleet average VOC emission rate trends for the longest running in-use light-duty gasoline Vehicle Surveillance Program (VSP) in Southern California. Tailpipe emissions data from a limited number of vehicles tested as part of the VSP show that the 2003 fleet average emissions decreased by about 80% for most VOCs relative to the 1995 fleet. Vehicle evaporative emission rates decreased more than 90% for most compounds from the 1999 to the 2003 fleet. Tailpipe benzene-normalized emission rate ratios for most compounds were relatively stable. Evaporative emission rate ratios and weight percentages have changed significantly from the 1999 fleet to the 2003 fleet indicating a significant change in the evaporative emission species patterns. The tailpipe NMHC (Non-Methane HydroCarbon) emission reductions observed between the 1995 fleet and the 2003 fleet likely resulted from the retirement of non-catalyst vehicles in the fleets (49%) and the combined effect of the turn-over of catalyst-equipped vehicles and switch to Phase III gasoline (27%). Our results are consistent with those observed in the Swiss tunnel study. Benzene-normalized emission rate ratios for C2 compounds, aldehydes, and 1,3 butadiene are much higher in tailpipe exhaust than those in evaporative emissions. C4-C5 hydrocarbon ratios in evaporative emissions are much higher than those in exhaust. C8 aromatic compound ratios are comparable for tailpipe and evaporative emissions (hot-soak). Such ratio differences can be used to estimate the relative contributions of vehicle exhaust and evaporative emission to ambient VOCs. The contribution of emissions from malfunctioning vehicles to total fleet emissions increased from 16% to 32% for the 1995 fleet to the 2003 fleet even though the percentage of malfunctioning vehicles in the fleet decreased from 10% to 5%. Most malfunctioning vehicles are vehicles that are at least 10 years old and generally have higher acetylene emission rate ratios. The effective identification and control of these malfunctioning vehicles will become increasingly important for improving mobile source emission estimates as well as reducing future tailpipe emissions.

Pang, Yanbo; Fuentes, Mark; Rieger, Paul

2014-02-01

126

National survey of MTBE and other VOCs in community drinking-water sources  

USGS Publications Warehouse

Methyl tert-butyl ether (MTBE) is a volatile organic compound (VOC) that is added to gasoline either seasonally or year round in many parts of the United States to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The chemical properties and widespread use of MTBE can result in contamination of private and public drinking-water sources. MTBE contamination is a concern in drinking water because of the compound's low taste and odor threshold and potential human-health effects.

Clawges, Rick M.; Rowe, Barbara L.; Zogorski, John S.

2001-01-01

127

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...

128

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

129

Controlling VOC and air toxic emissions from aircraft refinishing facilities - a new approach  

SciTech Connect

Aircraft refinishing facilities will soon face stringent emission reduction and pollution prevention requirements mandated by Federal, state and local regulations; compliance with these requirements will potentially involve extensive process adjustments and facility modifications. This paper presents the innovative approach that Hill Air Force Base is exploring to achieve cost effective regulatory compliance, yet maintain operational flexibility and accommodate high throughput requirements demanded by their target production levels. The approach encompasses two separate technological innovations: (1) Retrofit an existing C-130 aircraft hangar to accommodate recirculation to reduce the process exhaust flow rate up to 80%. (2) Vent the hangar exhaust to a biofiltration emission control device to achieve low cost VOC and organic air toxic emission reductions; an intermediate concentrator step is also being considered for installation. To ensure the installation of a safe, reliable, cost-effective, and fully integrated system, the program incorporates a multi-phase schedule that includes a detailed recirculation system assessment, a biofilter pilot scale evaluation, the installation and evaluation of an innovative safety monitor capable of providing instantaneous, speciated recirculation duct organic concentration data on a continuous basis, the development of detailed engineering design and system configuration plans, and the installation of a hangar ventilation system that is fully integrated with the emission control device. The paper focuses primarily on the recirculation system evaluation and innovative design elements that are under consideration. The program was initiated in May, 1996, and the projected completion date is Summer, 1998.

Ayer, J. [Air Quality Specialists, Newport Beach, CA (United States)

1997-12-31

130

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

131

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 1. ASSESSMENT OF CATALYTIC INCINERATION AND COMPETING CONTROLS  

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

132

Aeration recirculation in air and high purity oxygen systems for control of VOC emissions from wastewater aeration basins  

Microsoft Academic Search

A steady state circulating aeration system (CAS) model has been used to study the effects of volatility and degradability on the fate of VOCs in both air and high purity oxygen (HPO) systems. With an increase of the circulating ratio in an air CAS, air emissions by stripping can be significantly reduced for compounds of low degradability and high volatility.

H. Zhu; T. C. Keener; P. L. Bishop; T. L. Orton; M. Wang; K. F. Siddiqui

2009-01-01

133

PROJECTION METHODOLOGY FOR FUTURE STATE LEVEL VOLATILE ORGANIC COMPOUND EMISSIONS FROM STATIONARY SOURCES (VERSION 1.8)  

EPA Science Inventory

The report presents the model framework used to estimate state level and national future volatile organic compound (VOC) emissions and control costs for stationary industrial and utility sources. The framework involves a projection approach using the 1980 National Acid Precipitat...

134

Ozone Trends Across the United States over a Period of Decreasing NOx and VOC Emissions.  

PubMed

In this work, we evaluate ambient ozone trends at urban, suburban, and rural monitoring sites across the United States over a period of decreasing NOx and VOC emissions (1998-2013). We find that decreasing ozone trends generally occur in the summer, in less urbanized areas, and at the upper end of the ozone distribution. Conversely, increasing ozone trends generally occur in the winter, in more urbanized areas, and at the lower end of the ozone distribution. The 95(th) percentile ozone concentrations decreased at urban, suburban, and rural monitors by 1-2 ppb/yr in the summer and 0.5-1 ppb/yr in the winter. In the summer, there are both increasing and decreasing trends in fifth percentile ozone concentrations of less than 0.5 ppb/yr at urban and suburban monitors, while fifth percentile ozone concentrations at rural monitors decreased by up to 1 ppb/yr. In the winter, fifth percentile ozone concentrations generally increased by 0.1-1 ppb/yr. These results demonstrate the large scale success of U.S. control strategies targeted at decreasing peak ozone concentrations. In addition, they indicate that as anthropogenic NOx emissions have decreased, the ozone distribution has been compressed, leading to less spatial and temporal variability. PMID:25517137

Simon, Heather; Reff, Adam; Wells, Benjamin; Xing, Jia; Frank, Neil

2015-01-01

135

Efficient control of odors and VOC emissions via activated carbon technology.  

PubMed

This research study was undertaken to enhance the efficiency and economy of carbon scrubbers in controlling odors and volatile organic compounds (VOCs) at the wastewater collection and treatment facilities of the Bureau of Sanitation, City of Los Angeles. The butane activity and hydrogen sulfide breakthrough capacity of activated carbon were assessed. Air streams were measured for odorous gases and VOCs and removal efficiency (RE) determined. Carbon towers showed average to excellent removal of odorous compounds, VOCs, and siloxanes; whereas, wet scrubbers demonstrated good removal of odorous compounds but low to negative removal of VOCs. It was observed that the relative humidity and empty bed contact time are one of the most important operating parameters of carbon towers impacting the pollutant RE. Regular monitoring of activated carbon and VOCs has resulted in useful information on carbon change-out frequency, packing recommendations, and means to improve performance of carbon towers. PMID:25112027

Mohamed, Farhana; Kim, James; Huang, Ruey; Nu, Huong Ton; Lorenzo, Vlad

2014-07-01

136

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

137

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...

138

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...

139

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

140

Temperature and moisture effect on spore emission in the fungal biofiltration of hydrophobic VOCs.  

PubMed

The effect of temperature and moisture on the elimination capacity (EC), CO(2) production and spore emission by Fusarium solani was studied in biofilters packed with vermiculite and fed with n- pentane. Three temperatures (15, 25 and 35°C) were tested and the highest average EC (64 g m(-3) h(-1)) and lower emission of spores (2.0 × 10(3) CFU m(-3) air) were obtained at 25°C. The effect of moisture content of the packing material indicates that the highest EC (65 g m(-3) h(-1)) was obtained at 50 % moisture. However, lowest emission (1.3 × 10(3) CFU m(-3) air) was obtained at 80 % moisture. Furthermore, the results show that a slight decrease in spore emission was found with increasing moisture content. In all cases, the depletion of the nitrogen source in the biofilter induced the sporulation, a decay of the EC and increased spore emission. PMID:22375544

Vergara-Fernández, Alberto; Salgado-Ísmodes, Vanida; Pino, Miguel; Hernández, Sergio; Revah, Sergio

2012-01-01

141

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

142

Source apportionment of VOCs in the Los Angeles area using positive matrix factorization  

NASA Astrophysics Data System (ADS)

Eight 3-h speciated hydrocarbon measurements were collected daily by the South Coast Air Quality Management District (SCAQMD) as part of the Photochemical Assessment Monitoring Stations (PAMS) program during the summers of 2001-03 at two sites in the Los Angeles air basin, Azusa and Hawthorne. Over 30 hydrocarbons from over 500 samples at Azusa and 600 samples at Hawthorne were subsequently analyzed using the multivariate receptor model positive matrix factorization (PMF). At Azusa and Hawthorne, five and six factors were identified, respectively, with a good comparison between predicted and measured mass. At Azusa, evaporative emissions (a median of 31% of the total mass), motor vehicle exhaust (22%), liquid/unburned gasoline (27%), coatings (17%), and biogenic emissions (3%) factors were identified. Factors identified at Hawthorne were evaporative emissions (a median of 34% of the total mass), motor vehicle exhaust (24%), industrial process losses (15%), natural gas (13%), liquid/unburned gasoline (13%), and biogenic emissions (1%). Together, the median contribution from mobile source-related factors (exhaust, evaporative emissions, and liquid/unburned gasoline) was 80% and 71% at Azusa and Hawthorne, respectively, similar to previous source apportionment results using the chemical mass balance (CMB) model. There is a difference in the distribution among mobile source factors compared to the CMB work, with an increase in the contribution from evaporative emissions, though the cause (changes in emissions or differences between models) is unknown.

Brown, Steven G.; Frankel, Anna; Hafner, Hilary R.

143

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

144

Comparison of VOC emissions between air-dried and heat-treated Norway spruce ( Picea abies), Scots pine ( Pinus sylvesteris) and European aspen ( Populus tremula) wood  

NASA Astrophysics Data System (ADS)

Heat-treated wood is an increasingly popular decoration material. Heat-treatment improves dimensional stability of the wood and also prevents rot fungus growth. Although production of heat-treated wood has been rapidly increasing, there is only little information about the VOC emissions of heat-treated wood and its possible influences on indoor air quality. In the present study, VOC emissions from three untreated (air-dried) and heat-treated wood species were compared during a four weeks test period. It appeared that different wood species had clearly different VOC emission profiles. Heat-treatment was found to decrease VOC emissions significantly and change their composition. Especially, emissions of terpenes decreased from softwood samples and aldehydes from European aspen samples. Emissions of total aldehydes and organic acids were at the same level or slightly higher from heat treated than air-dried softwood samples. In agreement with another recent study, the emissions of furfural were found to increase and those of hexanal to decrease from all the wood species investigated. In contrast to air-dried wood samples, emissions of VOCs were almost in steady state from heat treated wood samples even in the beginning of the test.

Hyttinen, Marko; Masalin-Weijo, Marika; Kalliokoski, Pentti; Pasanen, Pertti

2010-12-01

145

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...

146

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

147

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...

148

Biological anoxic treatment of O?-free VOC emissions from the petrochemical industry: a proof of concept study.  

PubMed

An innovative biofiltration technology based on anoxic biodegradation was proposed in this work for the treatment of inert VOC-laden emissions from the petrochemical industry. Anoxic biofiltration does not require conventional O2 supply to mineralize VOCs, which increases process safety and allows for the reuse of the residual gas for inertization purposes in plant. The potential of this technology was evaluated in a biotrickling filter using toluene as a model VOC at loads of 3, 5, 12 and 34 g m(-3)h(-1) (corresponding to empty bed residence times of 16, 8, 4 and 1.3 min) with a maximum elimination capacity of ?3 g m(-3)h(-1). However, significant differences in the nature and number of metabolites accumulated at each toluene load tested were observed, o- and p-cresol being detected only at 34 g m(-3)h(-1), while benzyl alcohol, benzaldehyde and phenol were detected at lower loads. A complete toluene removal was maintained after increasing the inlet toluene concentration from 0.5 to 1 g m(-3) (which entailed a loading rate increase from 3 to 6 g m(-3)h(-1)), indicating that the system was limited by mass transfer rather than by biological activity. A high bacterial diversity was observed, the predominant phyla being Actinobacteria and Proteobacteria. PMID:23811365

Muñoz, Raúl; Souza, Theo S O; Glittmann, Lina; Pérez, Rebeca; Quijano, Guillermo

2013-09-15

149

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 ...

150

The Effectiveness of Aeration Recirculation in Controlling VOC Emissions from Publicly Owned Treatment Works  

Microsoft Academic Search

The effects of aeration recirculation on oxygen transfer and the fate of five volatile organic compounds (VOCs) commonly found in publicly owned treatment works (POTWs) influent are studied using various modeling approaches. The five compounds are benzene, chloroform, methylene chloride, toluene, and trichloroethylene. The models predict that the overall oxygen transfer efficiency can be increased by 96.7% at 50% aeration

Hongwei Zhu; Tim C. Keener; Tim L. Orton; Paul L. Bishop; Soon Jai Khang; Kaniz Siddiqui

1997-01-01

151

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

NASA Astrophysics Data System (ADS)

Advances in horizontal drilling and hydraulic fracturing over the past two decades have allowed access to previously unrecoverable reservoirs of natural gas and led to an increase in natural gas production. Intensive unconventional natural gas extraction has led to concerns about impacts on air quality. Unconventional natural gas production has the potential to emit vast quantities of volatile organic compounds (VOCs) into the atmosphere. Many VOCs can be toxic, can produce ground-level ozone or secondary organic aerosols, and can impact climate. This dissertation presents the results of experiments designed to validate VOC measurement techniques, to quantify VOC emission rates from natural gas sources, to identify source signatures specific to natural gas emissions, and to quantify the impacts of these emissions on potential ozone formation and human health. Measurement campaigns were conducted in two natural gas production regions: the Denver-Julesburg Basin in northeast Colorado and the Marcellus Shale region surrounding Pittsburgh, Pennsylvania. An informal measurement intercomparison validated the canister sampling methodology used throughout this dissertation for the measurement of oxygenated VOCs. Mixing ratios of many VOCs measured during both campaigns were similar to or higher than those observed in polluted cities. Fluxes of natural gas-associated VOCs in Colorado ranged from 1.5-3 times industry estimates. Similar emission ratios relative to propane were observed for C2-C6 alkanes in both regions, and an isopentane:n-pentane ratio ?1 was identified as a unique tracer for natural gas emissions. Source apportionment estimates indicated that natural gas emissions were responsible for the majority of C2-C8 alkanes observed in each region, but accounted for a small proportion of alkenes and aromatic compounds. Natural gas emissions in both regions accounted for approximately 20% of hydroxyl radical reactivity, which could hinder federal ozone standard compliance in downwind cities. A health risk assessment showed no increase in cancer or chronic non-cancer risk at locations near natural gas wells in Pennsylvania, but the contribution of natural gas emissions to total risk was 3-6 times higher near wells. These results will assist policy makers, natural gas producers, and citizen stakeholders in crafting effective policies to control VOC emissions from natural gas production activities.

Swarthout, Robert F.

152

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

153

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

154

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

SciTech Connect

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 VOCs 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) yr1 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 * 17% of the reference isoprene total. A greater impact was observed for 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 in ventories indicated significant spatial and temporal differences between the datasets especially for Australia, Southeast Asia and South America. MEGAN-MACC estimates of isoprene and*-pinene showed a reasonable agreement with surface flux measurements in the Amazon andthe model was able to capture the seasonal variation of emissions in this region.

Sindelarova, K.; Granier, Claire; Bouarar, I.; Guenther, Alex B.; Tilmes, S.; Stavrakou, T.; Muller, J. F.; Kuhn, U.; Stefani, P.; Knorr, W.

2014-09-09

155

Long-term Impact of Formaldehyde and VOC Emissions from Wood-based Products on Indoor Environments; and Issues with Recycled Products  

Microsoft Academic Search

This paper discusses the emission of formaldehyde and VOCs from wood-based panel products and the effect on indoor air quality (IAQ). The formaldehyde concentration monitored in four energy efficient test houses over a 7-year period has been included to illustrate the long-term effect of emissions from E1 wood-based panels used in dwellings. Formaldehyde emissions from wood-based floorboard obtained from investigation

Chuck W. F. Yu; Jeong Tai Kim

2012-01-01

156

Photochemical ozone creation potentials (POCPs) for different emission sources of organic compounds under European conditions estimated with a Master Chemical Mechanism  

NASA Astrophysics Data System (ADS)

Through the combined application of a speciated VOC emission inventory and an explicit chemical mechanism, a picture has been put together of the different contributions to photochemical ozone formation from 248 VOC emission source categories. The study has shown that the different VOC emission source categories show vastly different propensities for forming photochemical ozone as indexed by their photochemical ozone creation potentials (POCPs). POCPs range from close to zero for numerous processes, including halocarbon solvent usage, through to over 70 for diesel combustion and some reactive solvent and other product usage applications. The consequences of the large range in POCPs are highlighted for cost-effective VOC emission control strategies across north west Europe.

Derwent, R. G.; Jenkin, M. E.; Passant, N. R.; Pilling, M. J.

157

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

158

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...

159

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...

160

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 7. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-5  

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

161

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 8. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-6  

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

162

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 5. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-3  

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

163

Development of a Pulsed Secondary Electron Emission Gun and its Application to VOC Treatment  

NASA Astrophysics Data System (ADS)

An electron beam is widely used for various purposes in industry. We have developed a pulsed secondary electron emission gun (SEEG) which uses pulsed discharge and high voltage technology. The device has some inherent advantages, such as compactness in size and generation of a uniform and wide electron beam. The SEEG consists of a wire ion plasma source, a cathode plate in a vacuum chamber and an electron beam irradiation part. In this paper, we improved the SEEG for stable operation. Previously an abnormal electrical discharge in the vacuum chamber disturbed prolonged electron beam irradiation. Therefore, based on the simulation result of an electrical potential distribution, we installed a plate of reducing electric stress in the vacuum chamber. Then the stable operation of the SEEG became possible. In addition, we have conducted experiment on decomposition of toluene using the SEEG in N2 and Air. The decomposition rate in N2 was higher than that in air. The addition of O2 and increase of humidity in N2 decreased the decomposition rate. Reaction products such as benzene and xylene were identified in N2 by means of GC-MS. On the other hand, benzaldehyde and formic acid were identified in Air. It is conceivable that the difference of byproducts is caused by the presence or absence of OH radical.

Kato, Daisuke; Sugihara, Ryo; Shimizu, Masashi; Watanabe, Masato; Hotta, Eiki

164

Screening volatile organic compounds (VOCs) emissions from five marine phytoplankton species by head space gas chromatography/mass spectrometry (HS-GC/MS).  

PubMed

Five marine cosmopolitan phytoplankton species namely; Calcidiscus leptoporus, Emiliania huxleyi, Phaeodactylum tricornutum, Chaetoceros neogracilis and Dunaliella tertiolecta were screened for emissions of selected VOCs using head space gas chromatography/mass spectrometry (HS-GC/MS) in single ion mode. The VOCs investigated included isoprene and various halogenated compounds. Among the different algae groups, the two diatoms Ch. neogracilis and P. tricornutum were the strongest emitters of methyl bromide (CH3Br), and Ch. neogracilis was the strongest emitter of isoprene. Furthermore, we present evidence that several chlorinated organic compounds, normally considered as anthropogenic, can be produced from marine phytoplankton (namely chloroform, dichloromethane, trichloroethylene, tetrachloroethylene, chlorobenzene and dichlorobenzene). PMID:18392274

Colomb, Aurélie; Yassaa, Noureddine; Williams, Jonathan; Peeken, Ilka; Lochte, Karin

2008-03-01

165

SOURCES OF COPPER AIR EMISSIONS  

EPA Science Inventory

The report gives results of a study to update estimates of atmospheric emissions of copper and copper compounds in the U.S. Source categories evaluated included: metallic minerals, primary copper smelters, iron and steel making, combustion, municipal incineration, secondary coppe...

166

Determinants of personal, indoor and outdoor VOC concentrations: an analysis of the RIOPA data.  

PubMed

Community and environmental exposure to volatile organic compounds (VOCs) has been associated with a number of emission sources and activities, e.g., environmental tobacco smoke and pumping gasoline. Such factors have been identified from mostly small studies with relatively limited information regarding influences on VOC levels. This study uses data from the Relationship of Indoor Outdoor and Personal Air (RIOPA) study to investigate environmental, individual and social determinants of VOC concentrations. RIOPA included outdoor, indoor and personal measurements of 18 VOCs from 310 non-smoking households and adults in three cities and two seasons, and collected a wide range of information pertaining to participants, family members, households, and neighborhoods. Exposure determinants were identified using stepwise regressions and linear mixed-effect models. Most VOC exposure (66 to 78% of the total exposure, depending on VOC) occurred indoors, and outdoor VOC sources accounted for 5 (d-limonene) to 81% (carbon tetrachloride) of the total exposure. Personal exposure and indoor measurements had similar determinants, which depended on the VOC. Gasoline-related VOCs (e.g., benzene, methyl tertiary butyl ether) were associated with city, residences with attached garages, self-pumping of gas, wind speed, and house air exchange rate (AER). Odorant and cleaning-related VOCs (e.g., 1,4-dichlorobenzene and chloroform) also were associated with city and AER, and with house size and family members showering. Dry-cleaning and industry-related VOCs (e.g., tetrachloroethylene and trichloroethylene) were associated with city, residence water supply type, and dry-cleaner visits. These and other relationships were significant, explained from 10 to 40% of the variation, and are consistent with known emission sources and the literature. Outdoor concentrations had only two common determinants: city and wind speed. Overall, personal exposure was dominated by the home setting, although a large fraction of VOC concentrations were due to outdoor sources. City, personal activities, household characteristics and meteorology were significant determinants. PMID:24034784

Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

2013-10-01

167

Determinants of personal, indoor and outdoor VOC concentrations: An analysis of the RIOPA data  

PubMed Central

Community and environmental exposure to volatile organic compounds (VOCs) has been associated with a number of emission sources and activities, e.g., environmental tobacco smoke and pumping gasoline. Such factors have been identified from mostly small studies with relatively limited information regarding influences on VOC levels. This study uses data from the Relationship of Indoor Outdoor and Personal Air (RIOPA) study to investigate environmental, individual and social determinants of VOC concentrations. RIOPA included outdoor, indoor and personal measurements of 18 VOCs from 310 non-smoking households and adults in three cities and two seasons, and collected a wide range of information pertaining to participants, family members, households, and neighborhoods. Exposure determinants were identified using stepwise regressions and linear mixed-effect models. Most VOC exposure (66 to 78% of the total exposure, depending on VOC) occurred indoors, and outdoor VOC sources accounted for 5 (d-limonene) to 81% (carbon tetrachloride) of the total exposure. Personal exposure and indoor measurements had similar determinants, which depended on the VOC. Gasoline-related VOCs (e.g., benzene, methyl tertiary butyl ether) were associated with city, residences with attached garages, self-pumping of gas, wind speed, and house air exchange rate (AER). Odorant and cleaning-related VOCs (e.g., 1,4-dichlorobenzene and chloroform) also were associated with city and AER, and with house size and family members showering. Dry-cleaning and industry-related VOCs (e.g., tetrachloroethylene and trichloroethylene) were associated with city, residence water supply type, and dry-cleaner visits. These and other relationships were significant, explained from 10 to 40% of the variation, and are consistent with known emission sources and the literature. Outdoor concentrations had only two common determinants: city and wind speed. Overall, personal exposure was dominated by the home setting, although a large fraction of VOC concentrations were due to outdoor sources. City, personal activities, household characteristics and meteorology were significant determinants. PMID:24034784

Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

2014-01-01

168

Biofiltration control of VOC and air toxic emissions: n-Butane and benzene  

SciTech Connect

n-Butane and benzene vapors are routinely observed in urban atmospheres. Their presence in urban airsheds is of concern because of their ozone production potential as volatile organic compounds (VOCs) and/or potential toxicity. Also, these saturated hydrocarbons are representative of airborne aliphatic and aromatic compounds. Separate laboratory studies have been conducted on the biological elimination of n-butane (n-C{sub 4}H{sub 10}) and benzene (C{sub 6}H{sub 6}) from airstreams using treated compost biofilters. The removal efficiencies were found to exceed 90% for a conditioned biofilter medium and pollutant low concentrations (< 25 ppm) and zeroth order kinetics at higher concentrations (> 100 ppm), whereas benzene vapor elimination followed zeroth order kinetics at concentrations up to 200 ppm. The maximum n-butane and benzene elimination capacities observed for the compost biofilters and conditions employed were 25 and 70 g pollutant m{sup -3} h{sup -1}, respectively. 13 refs., 6 figs., 2 tabs.

Allen, E.R. [Univ. of Florida, Gainesville, FL (United States)

1996-12-31

169

A survey of California plant species with a portable VOC analyzer for biogenic emission inventory development  

NASA Astrophysics Data System (ADS)

An accurate estimate of the magnitude of biogenic volatile organic compound (BVOC) emissions in California's airsheds is critical for formulating effective strategies to reduce concentrations of fine particles, ozone, and other secondary air pollutants which affect human health and reduce yields of agricultural crops. However, California's natural and urban landscapes contain more than 6000 species, and the BVOC emissions from only a small fraction of these species have been characterized by quantitative measurements. A taxonomic method has been proposed to assign BVOC emission rate measurements to unmeasured species, but data are needed for additional plant families and genera to further develop and test this taxonomic approach. In the present study, BVOC emissions from more than 250 plant species were measured through a semi-quantitative method employing calibrated portable analyzers with photoionization detectors (PID). Replicate samples of live foliage were placed in plastic bags, in both light and darkened conditions, and the BVOC emissions categorized as low, medium or high. To validate our approach, for 63 plant species we compared our PID-measured BVOC emissions with published values, based on gas chromatography (GC) or GC-mass spectrometry, and found them to be well correlated. The method employed was more suited for detecting compounds with relatively higher emission rates, such as isoprene, than compounds with low emission rates, which could include monoterpenes and oxygenated compounds. For approximately 200 plant species not previously measured, the results provide further evidence that plant taxonomy can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera.

Karlik, John F.; McKay, Alistair H.; Welch, Jason M.; Winer, Arthur M.

170

Southern California Edison's (SCE) Research Program for Industrial Volatile Organic Compound (VOC) Emissions Control  

E-print Network

in this program involves the evaluation of portable emission control systems. The systems are sized to process a slipstream of 100 to 300 cfm of solvent laden air (SLA) vented from the industrial processes. A number of different emission control technologie... to storage. Different types and qualit'es of foam are produced from different mixtures of base materials and differen concentrations of foaming agents. Duri g the demonstration, a slipstream of the exhaust was directed to the control equipment...

Sung, R. D.; Cascone, R.; Reese, J.

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

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...

173

Plant leaves as indoor air passive samplers for volatile organic compounds (VOCs).  

PubMed

Volatile organic compounds (VOCs) enter indoor environments through internal and external sources. Indoor air concentrations of VOCs vary greatly but are generally higher than outdoors. Plants have been promoted as indoor air purifiers for decades, but reports of their effectiveness differ. However, while air-purifying applications may be questionable, the waxy cuticle coating on leaves may provide a simple, cost-effective approach to sampling indoor air for VOCs. To investigate the potential use of plants as indoor air VOC samplers, a static headspace approach was used to examine the relationship between leaf and air concentrations, leaf lipid contents and octanol-air partition coefficients (Koa) for six VOCs and four plant species. The relationship between leaf and air concentrations was further examined in an actual residence after the introduction of several chlorinated VOC emission sources. Leaf-air concentration factors (LACFs), calculated from linear regressions of the laboratory headspace data, were found to increase as the solvent extractable leaf lipid content and Koa value of the VOC increased. In the studies conducted in the residence, leaf concentrations paralleled the changing air concentrations, indicating a relatively rapid air to leaf VOC exchange. Overall, the data from the laboratory and residential studies illustrate the potential for plant leaves to be used as cost effective, real-time indoor air VOC samplers. PMID:25434272

Wetzel, Todd A; Doucette, William J

2015-03-01

174

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

175

TV picture-tube manufacturer uses regenerative catalytic oxidizer to reduce VOC emissions  

SciTech Connect

Toshiba Display Services, a television picture-tube manufacturer in Horseheads, NY, recently was able to meet stringent state regulations to reduce emissions from two of its film applications lines by installing a regenerative catalytic oxidation system. Toshiba officials initially evaluated several technologies to control volatile organic compounds. After deciding that oxidation was the best technology for its facility, the company invited a number of suppliers to submit proposals. Because all of the oxidation technologies considered by Toshiba had the capability to achieve the destruction and removal efficiency requirement, the company combined the second and third decision elements and conducted an in-depth comparison of the initial capital and ongoing operating costs for each proposal. Officials narrowed the field to two systems--the lowest-cost regenerative thermal oxidation system on the market and a regenerative catalytic oxidation system. The company selected St. Louis, Mo.-based Monsanto Enviro-Chem Systems Inc., to install its DynaCycle{reg_sign} regenerative catalytic oxidation system, marking the first Dyna-Cycle installation in a US television picture-tube facility.

NONE

1995-11-01

176

Using Pre-Modeled Scenarios to Estimate Groundwater VOC Concentrations Resulting from Vadose Zone Sources  

SciTech Connect

Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. To support selection of an appropriate endpoint for the SVE remedy, an evaluation is needed to determine whether vadose zone contamination has been diminished sufficiently to protect groundwater. When vapor-phase transport is an important component of the overall contaminant fate and transport from a vadose zone source, the contaminant concentration expected in groundwater is controlled by a limited set of parameters, including specific site dimensions, vadose zone properties, and source characteristics. An approach was developed for estimating the contaminant concentration in groundwater resulting from a contaminant source in the vadose zone based on pre-modeling contaminant transport for a matrix of parameter value combinations covering a range of potential site conditions. An interpolation and scaling process are then applied to estimate groundwater impact for site-specific conditions.

Oostrom, Martinus; Truex, Michael J.; Rice, Amy K.; Johnson, Christian D.; Carroll, Kenneth C.; Becker, Dave; Simon, Michelle A.

2014-04-28

177

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

178

A Novel Multifunctional Photocatalytic Oxidation (PCO) Gel Preventing Mold\\/Mildew Growth and Volatile Organic Compound (VOC) Emission  

Microsoft Academic Search

With the increasing time people spend indoors, the indoor environment quality draws more and more attention. The concentration of indoor pollutants is usually much higher than outdoors, in which volatile organic compounds (VOCs) and mold\\/mildew are both major pollutants and cause many health problems to residents. Efforts devoted from academy and industry to protecting people from indoor environment problems are

Yao Gao

2011-01-01

179

Biogenic VOC Emissions Measured by Solid Phase Microextraction (SPME) Fibers, Proton Transfer Reaction Mass Spectrometry (PTR-MS), and In-situ Gas Chromatography (GC)  

NASA Astrophysics Data System (ADS)

Chemical ozone loss due to reactions with biogenic VOCs has been shown to dominate ozone flux measured at Blodgett Forest, a coniferous forest in the Sierra Nevada Mountains of California. Here we report recent efforts to measure the specific biogenic VOCs involved in this chemistry at Blodgett Forest. During summer 2005, we enclosed branches of Ponderosa pine, manzanita, and ceanothus species and made VOC emission measurements by proton transfer reaction mass spectrometry (PTR-MS), solid phase microextraction (SPME) on fibers followed by direct injection into a gas chromatograph with an ion trap mass spectrometer (GC-ITMS), and by in-situ GC with a flame ionization detector (GC-FID). Zero air, with ambient CO2 concentrations, flowed through a 2-chamber system. The chamber placed directly over the branch had a 20 second residence time, and was immediately followed by a reaction chamber with a 2 minute residence time. The PTR-MS and GC-FID measurement cycled between each of the two chambers and the zero air supply. SPME fibers (65 ?m PDMS/DVB field portable) were used to sample the branch chamber. Several sesquiterpene, monoterpene, and oxygenated primary emissions were identified. The SPME fibers were particularly useful for detecting sesquiterpenes which are typically difficult to measure due to their high reactivity in the forest canopy and losses in sampling lines. Comparisons of SPME fiber data with PTR-MS and GC-FID data for sesquiterpenes (m/z 205), 4-allylanisole (m/z 149), and monoterpenes (m/z 137) will be presented to assess the actual emission rates and the complimentary information provided by each measurement approach.

Bouvier-Brown, N. C.; Holzinger, R.; Palitzsch, K.; Goldstein, A. H.

2005-12-01

180

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

181

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...

182

An in-source stretched membrane inlet for on-line analysis of VOCs in water with single photon ionization TOFMS.  

PubMed

An in-source, stretched, hollow fiber membrane (HFM) inlet has been developed to improve the sensitivity of on-line time-of-flight mass spectrometry (TOFMS) with a vacuum ultraviolet (VUV) lamp based single photon ionization (SPI) source for the direct analysis of liquid samples. A 2-cm HFM was stretched to 8 cm in length, and placed in the ion source and directly under the VUV lamp window with a distance of 15 mm. Compared with the conventional flow-through configuration under the same experimental conditions, the signal intensities of selected volatile organic compounds (VOCs) of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), benzene, toluene and p-xylene were increased over 5-fold in magnitude, and the response time was shortened to one-third. The limits of detection (LOD) of MTBE, ETBE, benzene, toluene and p-xylene ranged from 0.25 to 1.3 ?g L(-1) with a measurement time of 60 s, and three orders of linear range were obtained with correlation coefficients of 0.9972-0.9992. The present results suggest that the in-source stretched HFM is a simple and effective way to increase the sensitivity and shorten response time of the membrane inlet, and we believe that it will also be beneficial to other types of on-line mass spectrometer for the on-line analysis of VOCs in water with a VUV lamp based SPI ion source. PMID:23907373

Hou, Keyong; Li, Fanglong; Chen, Wendong; Chen, Ping; Xie, Yuanyuan; Zhao, Wuduo; Hua, Lei; Pei, Kemei; Li, Haiyang

2013-10-01

183

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 ...

184

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...

185

DEVELOPING A NO-VOC WOOD TOPCOAT  

EPA Science Inventory

The paper reports an evaluation of a new low-VOC (volatile organic compound) wood coating technology, its performance characteristics, and its application and emissions testing. The low-VOC wood coating selected for the project was a two-component, water-based epoxy coating. Poly...

186

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...

187

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

188

Source apportionment of stack emissions from research and development facilities using positive matrix factorization  

NASA Astrophysics Data System (ADS)

Research and development (R&D) facility emissions are difficult to characterize due to their variable processes, changing nature of research, and large number of chemicals. Positive matrix factorization (PMF) was applied to volatile organic compound (VOC) concentrations measured in the main exhaust stacks of four different R&D buildings to identify the number and composition of major contributing sources. PMF identified between 9 and 11 source-related factors contributing to stack emissions, depending on the building. Similar factors between buildings were major contributors to trichloroethylene (TCE), acetone, and ethanol emissions; other factors had similar profiles for two or more buildings but not all four. At least one factor for each building was identified that contained a broad mix of many species and constraints were used in PMF to modify the factors to resemble more closely the off-shift concentration profiles. PMF accepted the constraints with little decrease in model fit.

Ballinger, Marcel Y.; Larson, Timothy V.

2014-12-01

189

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...

190

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...

191

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

PubMed

The characteristic ratios of volatile organic compounds (VOCs) to i-pentane, the indicator of vehicular emissions, were employed to apportion the vehicular and non-vehicular contributions to reactive species in urban Shanghai. Two kinds of tunnel experiments, one tunnel with more than 90% light duty gasoline vehicles and the other with more than 60% light duty diesel vehicles, were carried out to study the characteristic ratios of vehicle-related emissions from December 2009 to January 2010. Based on the experiments, the characteristic ratios of C6-C8 aromatics to i-pentane of vehicular emissions were 0.53±0.08 (benzene), 0.70±0.12 (toluene), 0.41±0.09 (m,p-xylenes), 0.16±0.04 (o-xylene), 0.023±0.011 (styrene), and 0.15±0.02 (ethylbenzene), respectively. The source apportionment results showed that around 23.3% of C6-C8 aromatics in urban Shanghai were from vehicular emissions, which meant that the non-vehicular emissions had more importance. These findings suggested that emission control of non-vehicular sources, i.e. industrial emissions, should also receive attention in addition to the control of vehicle-related emissions in Shanghai. The chemical removal of VOCs during the transport from emissions to the receptor site had a large impact on the apportionment results. Generally, the overestimation of vehicular contributions would occur when the VOC reaction rate constant with OH radicals (kOH) was larger than that of the vehicular indicator, while for species with smaller kOH than the vehicular indicator, the vehicular contribution would be underestimated by the method of characteristic ratios. PMID:25597688

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

2015-01-01

192

Rai, A.C., Guo, B., Lin, C.H., Zhang, J., Pei, J., and Chen, Q. 2014. "Ozone reaction with clothing and its initiated VOC 1 emissions in an environmental chamber," Indoor Air, 24, 49-58.2  

E-print Network

clothing, skin, and hair are30 important indoor air pollutants. This paper studied the ozone reactions with clothing and its initiated VOC 1 emissions in an environmental chamber," Indoor Air, 24, 49-58.2 Ozone33 the indoor environment.34 Introduction35 The typical ozone level in the ambient air at ground

Chen, Qingyan "Yan"

193

Characterization of emissions sources in the California-Mexico Border Region during Cal-Mex 2010  

NASA Astrophysics Data System (ADS)

The California-Mexico border region provides an opportunity to evaluate the characteristics of the emission processes in rapidly expanding urban areas where intensive international trade and commerce activities occur. Intense anthropogenic activities, biomass burning, as well as biological and geological sources significantly contribute to high concentration levels of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides (NOx), volatile organic compounds (VOCs), air toxics, and ozone observed in the California-US Baja California-Mexico border region. The continued efforts by Mexico and US for improving and updating the emissions inventories in the sister cities of San Diego-Tijuana and Calexico-Mexicali has helped to understand the emission processes in the border region. In addition, the recent Cal-Mex 2010 field campaign included a series of measurements aimed at characterizing the emissions from major sources in the California-Mexico border region. In this work we will present our analyzes of the data obtained during Cal-Mex 2010 for the characterization of the emission sources and their use for the evaluation of the recent emissions inventories for the Mexican cities of Tijuana and Mexicali. The developed emissions inventories will be implemented in concurrent air quality modeling efforts for understanding the physical and chemical transformations of air pollutants in the California-Mexico border region and their impacts.

Zavala, M. A.; Lei, W.; Li, G.; Bei, N.; Barrera, H.; Tejeda, D.; Molina, L. T.; Cal-Mex 2010 Emissions Team

2010-12-01

194

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...

195

Removal of volatile organic compounds (VOC`s) generated by Forest Product Industries using biofiltration technology  

SciTech Connect

Implementation of Clean Air Act Title V and the increasing environmental concerns of the public are imposing greater demands on the Forest Product industries to control their air emissions. As implementation of this Clean Air Act has begun, Forest Product Industries are recognizing the overall lack of historical emissions data, emissions testing information and knowledge of the economics of emission control technologies needed to reduce emissions. This study was undertaken to evaluate the types of VOC`s produced in drying and pressing wood composites, and determine how effective biofiltration technology could be used in reducing the levels of these products before they are released into the air. More specifically, the experiments were conducted to isolate microorganisms capable of degrading VOC`s and determine their biodegradation rates using bench scale biofilters.

Gilliland, G.A. [Eastman Chemical Company, Longview, TX (United States); Ramaswami, R.D.; Patel, D.N. [Grant Environmental, Englewood, CO (United States)] [and others

1995-12-31

196

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

197

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

198

Indoor air quality (IAQ) assessment in a multistorey shopping mall by high-spatial-resolution monitoring of volatile organic compounds (VOC).  

PubMed

In order to assess indoor air quality (IAQ), two 1-week monitoring campaigns of volatile organic compounds (VOC) were performed in different areas of a multistorey shopping mall. High-spatial-resolution monitoring was conducted at 32 indoor sites located in two storehouses and in different departments of a supermarket. At the same time, VOC concentrations were monitored in the mall and parking lot area as well as outdoors. VOC were sampled at 48-h periods using diffusive samplers suitable for thermal desorption. The samples were then analyzed with gas chromatography-mass spectrometry (GC-MS). The data analysis and chromatic maps indicated that the two storehouses had the highest VOC concentrations consisting principally of terpenes. These higher TVOC concentrations could be a result of the low efficiency of the air exchange and intake systems, as well as the large quantity of articles stored in these small spaces. Instead, inside the supermarket, the food department was the most critical area for VOC concentrations. To identify potential emission sources in this department, a continuous VOC analyzer was used. The findings indicated that the highest total VOC concentrations were present during cleaning activities and that these activities were carried out frequently in the food department. The study highlights the importance of conducting both high-spatial-resolution monitoring and high-temporal-resolution monitoring. The former was able to identify critical issues in environments with a complex emission scenario while the latter was useful in interpreting the dynamics of each emission source. PMID:24448884

Amodio, M; Dambruoso, P R; de Gennaro, Gianluigi; de Gennaro, L; Loiotile, A Demarinis; Marzocca, A; Stasi, F; Trizio, L; Tutino, M

2014-12-01

199

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

200

Spatial and temporal variations of PAMS VOCs in the northeast  

SciTech Connect

The effect of precursor pollutants on the formation and fate of ozone is of major concern in the Northeastern US. Hydrocarbon and carbonyl compounds measured at 15 Photochemical Assessment Monitoring Station (PAMS) sites in the Northeast are being investigated as a part of a data analysis effort sponsored by the Coordinating Research Council. One of the objectives of the volatile organic compound (VOC) analyses is to develop an understanding of the variability, spatial patterns, and diurnal patterns across the Northeast. This understanding is important for assessing transport of ozone and precursors, assessing model inputs and results, evaluating emission inventories, and assessing the efficacy of VOC/NO{sub x} controls. Analyses discussed in this paper include preliminary investigations of the spatial and temporal variation in isoprene concentrations, primarily associated with biogenic emissions; examination of ratios of species with different reactivity rates for temporal and spatial trends; and investigation of key differences among sites regarding speciation, relative age, and relative reactivity of the VOC to obtain clues into transport processes and emission sources.

Main, H.H.; Roberts, P.T.; Haste, T.L. [Sonoma Technology, Inc., Santa Rosa, CA (United States)

1997-12-31

201

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

202

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...

203

Development of a combined real time monitoring and integration analysis system for volatile organic compounds (VOCs).  

PubMed

A combined integration analysis and real time monitoring (Peak Capture System) system was developed for volatile organic compounds (VOCs). Individual integration analysis and real time monitoring can be used to qualitatively and quantitatively analyze VOCs in the atmosphere and in indoor environments and determine the variation in total VOC (TVOC) concentration with time, respectively. In the Peak Capture System, real time monitoring was used to predict future elevations in the TVOC concentration (peak), and this was used an indicator of when to collect (capture) ambient air samples for integration analysis. This enabled qualitative and quantitative analysis of VOCs when the TVOC concentration was high. We developed an algorithm to predict variation in the TVOC concentration, and constructed an automatic system to initiate air sampling for integration analysis. With the system, auto-sampling and analysis of VOCs in a conventional house were conducted. In comparison with background concentrations, the results of peak analysis enabled identification of compounds whose concentration rose. This also enabled an evaluation of possible VOC emission sources. PMID:21317996

Oka, Kentaro; Iizuka, Atsushi; Inoue, Yasuo; Mizukoshi, Atsushi; Noguchi, Miyuki; Yamasaki, Akihiro; Yanagisawa, Yukio

2010-12-01

204

Global data set 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 data set of biogenic volatile organic compounds (BVOC) available on a monthly basis for the time period of 1980-2010. This data set, developed under the Monitoring Atmospheric Composition and Climate project (MACC), 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 data sets 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.

2014-09-01

205

Compost spreading in Mediterranean shrubland indirectly increases biogenic emissions by promoting growth of VOC-emitting plant parts  

NASA Astrophysics Data System (ADS)

We investigated the effect of sewage sludge compost spreading on plant growth and leaf terpene emissions and content of Quercus coccifera, Rosmarinus officinalis and Cistus albidus in a Mediterranean shrubland. Measurements were performed during 3 consecutive summers on 2 different plots treated in 2002 or 2007 with 50 or 100 tons of compost per hectare, corresponding to observations carried out 2 months to 7 years after spreading. A slight nutrient enrichment of soil and leaves ( R. officinalis and C. albidus) was observed, especially for phosphorous. Terpene emissions were not affected by compost spreading, although they tended to increase on treated plots after 6 and 7 years for R. officinalis and C. albidus respectively. Terpene content was not affected by any compost treatment. Leaf and stem growth were significantly enhanced by compost spreading after 2 and/or 7 years in all species with little difference between doses. Total leaf biomass on the last growth units was increased by more than 50% in C. albidus and more than 90% in Q. coccifera. The results suggest that compost spreading in Meditteranean shrublands has no or little direct effect on leaf terpene emissions, but indirectly leads to their increase through leaf biomass enhancement. Simulation of terpene emissions at stand level revealed an increase of terpene fluxes ranging between 6 and 13%, depending on the plant species. Overall, compost spreading was assessed to result in an emission rate of 1.1 kg ha -1 y -1 for a typical Q. coccifera shrubland, but can reach 2.6 kg ha -1 y -1 for a typical R. officinalis shrubland.

Olivier, Romain; Lavoir, Anne-Violette; Ormeño, Elena; Mouillot, Florent; Greff, Stéphane; Lecareux, Caroline; Staudt, Michael; Fernandez, Catherine

2011-07-01

206

Non-Controlled Emissión of VOCs from Arico's Landfill, Tenerife, Canary Islands  

NASA Astrophysics Data System (ADS)

Landfills are important sources of CH4 as well as other trace gas components to the environment. A large number of organic volatile components (VOCs) are present as tracers in landfill gases, and they are considered to be carcinogenic and toxic. In order to control the emissions of these contaminants to the atmosphere, extraction systems to recover biogas are installed in landfills. However, a significant amount of these emissions could be released to the atmosphere through the surface environment in a diffuse form, also known as a non-controlled emission of landfill gases. The aim of this study is evaluate the non-controlled emission of VOCs from Arico's landfill. The Arico landfill has an extension of 0.35 km2, and about 1,546 tons of municipal solid waste (MSW) is daily deposited. A biogas extraction system was installed at the Arico landfill between 1998 and 1999. A non-controlled VOCs emission survey of 133 sampling sites was carried out during August, 2002. Surface CO2 efflux measurements were performed by means of a portable NDIR spectrometer and according to the accumulation chamber method. Surface CO2 efflux ranged from 1 to 10,580 gm-2d-1. At each sampling site, surface landfill gas samples were collected at 40 cm deep using a metallic probe. These gas samples were analyzed within 24 hours by means of GC-MS. Non-controlled emission rate of VOCs were estimated by multiplying surface CO2 efflux times (VOCs)i/CO2 weight ratio at each sampling site, respectively. The spatial distributions of VOCs at the Arico's landfill showed a different distribution pattern for each volatile component and it is related to actual use of the landfill. Taking into consideration the spatial distribution of the VOCs efflux values as well as the extension of the landfill, the non-controlled emission of VOCs to the atmosphere by Arico's landfill was estimated about 2108 Kgd-1 of which 1638 Kgd-1 are BTEX emissions.

Dionis, S.; de La Rosa, D. N.; Lima, R. N.; Nolasco, D.; Salazar, J. L.; Hernández, P. A.; Pérez, N. M.

2003-12-01

207

Applicability of gasoline containing ethanol as Thailand's alternative fuel to curb toxic VOC pollutants from automobile emission  

Microsoft Academic Search

Emission rates of benzene, toluene, m-xylene, formaldehyde and acetaldehyde were measured in a fleet of 16 in-use vehicles. The test was performed on a chassis dynamometer incorporated with Bangkok Driving Cycle test mode. Three different test fuels: unleaded gasoline, gasoline blended with 10% ethanol (E10) and gasoline blended with 15% ethanol (E15) were used to determine the different compositions of

Shing Tet Leong; S Muttamara; Preecha Laortanakul

2002-01-01

208

Measurements of Volatile Organic Compounds (VOCs) on Board of the Zeppelin NT during the PEGASOS Campaign in 2012  

NASA Astrophysics Data System (ADS)

Volatile Organic Compounds (VOCs) are mostly emitted at the ground and are degraded by the reactions with OH, NO3 or O3 as they rise upwards in the atmosphere. VOCs play an important role as sources and sinks for radicals in the troposphere. Up to date, most of the VOC measurements were performed from ground based platforms; the profile measurements across the whole planetary boundary layer (PBL) are still quite limited which restrained the exploring of the VOCs chemistry of the entire PBL. This although these measurements are particularly interesting, as most of the chemistry of the VOC degradation in the troposphere takes place in the PBL. Moreover, fast VOCs measurements utilizing Gas Chromatography coupled with Mass Spectrometry (GC-MS) are a challenge due to the great chemical variability of VOC species. Therefore accurate in-situ measurements of VOCs together with other species as CO, NOx, O3 and the OH reactivity, encompassing different levels of altitude and fast time resolution, would essentially improve the understanding of the VOC distribution in the lower troposphere. Here we present the setup and the modifications of the fast GC-MS system and the results of the PEGASOS Zeppelin campaigns in summer 2012. First, we present our developments and modifications of an in-flight GC-MS system to detect volatile non methane hydrocarbons (NMHC) with a time resolution of 3 minutes and a detection limit in the order of 2 pptv. The modified setup enabled us to analyze 70 different VOC species, ranging from alkanes (C4 to C11), aromatics and terpenes to oxygenated hydrocarbons (OVOC) such as alcohols and aldehydes. Second, in contrast to previous airplane studies also utilizing a GC-MS system, the Zeppelin NT as a measuring platform during the PEGASOS campaign enabled us to measure vertical profiles up to 1500m at low travelling speeds which means a high spatial resolution. We will present results for selected VOC that offer new insights on height profiles encompassing different emission regimes (anthropogenic and biogenic) in both the Netherlands and in Italy, and on the fate of VOCs in the nocturnal boundary layer. Third, we also present how the VOC concentrations relate to other substances such as CO, NOx, O3 and the OH reactivity. Especially the comparison of VOC Data with the measured OH reactivity will reveal more insight into the 'missing reactivity'. Acknowledgement: PEGASOS project funded by the European Commission under the Framework Program 7 (FP7-ENV-2010-265148)

Jäger, Julia; Hofzumahaus, Andreas; Beck, Harry; Rohrer, Franz; Broch, Sebastian; Fuchs, Hendrik; Gomm, Sebastian; Holland, Frank; Lu, Keding; Kiendler-Scharr, Astrid; Mentel, Thomas; Rose, Bernhard; Wegener, Robert; Wahner, Andreas

2013-04-01

209

Underestimated public health risks caused by overestimated VOC removal in wastewater treatment processes.  

PubMed

The uncontrolled release of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) and the adverse health effects on the public have been of increasing concern. In this study, a lab-scale bioreactor was prepared to analyze the mass distribution of three aromatic (benzene, toluene, and xylenes) and four chlorinated VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) among the air, water and sludge phases in wastewater treatment processes. The VOC distribution through a full-scale WWTP in northern China was further investigated with respect to the effects of seasonal temperature variations and treatment technologies, followed by the cancer risk assessment using a steady-state Gaussian plume model (Industrial Source Complex) to simulate the atmospheric behaviors of the VOCs emitted from the WWTP. It was found that three aromatic hydrocarbons, notably benzene, were more readily released from the wastewater into the atmosphere, whereas the chlorinated compounds except chloroform were mainly present in the water phase through the treatment processes. The primary clarifier was the technology releasing high levels of VOCs into the atmosphere from the wastewater. The extents of volatilization or biodegradation, two important mechanisms to remove VOCs from wastewater, appeared to be determined by the physicochemical characteristics of the compounds, as the influence of treatment technologies (e.g., aeration) and seasonal temperature variations was rather limited. More importantly, the people living in the areas even more than 4 km away from the WWTP were still potentially exposed to cancer risks exceeding the regulatory threshold limit. The findings described the complex nature of VOC emissions from WWTPs and quantitatively indicated that the associated health impacts on the public near the WWTPs could be severely underestimated, whereas their treatment efficiencies by wastewater treatment technologies were overestimated. Instead of fully controlling the VOC release from WWTPs, the identification and abatement of important VOC species with regard to the atmospheric emission and health concerns is one possible alternative approach to effectively minimize the environmental and public health impacts by VOCs released from this particular source. PMID:24337048

Yang, Junchen; Wang, Kun; Zhao, Qingliang; Huang, Likun; Yuan, Chung-Shin; Chen, Wei-Hsiang; Yang, Wen-Bin

2014-02-01

210

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

NASA Astrophysics Data System (ADS)

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

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

211

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

212

Source Apportionment of Stack Emissions from Research and Development Facilities Using Positive Matrix Factorization  

SciTech Connect

Emissions from research and development (R&D) facilities are difficult to characterize due to the wide variety of processes used, changing nature of research, and large number of chemicals. Positive matrix factorization (PMF) was applied to volatile organic compounds (VOCs) concentrations measured in the main exhaust stacks of four different R&D buildings to identify the number and composition of major contributing sources. PMF identified from 9-11 source-related factors contributing to the stack emissions depending on the building. The factors that were similar between buildings were major contributors to trichloroethylene (TCE), acetone, and ethanol emissions. Several other factors had similar profiles for two or more buildings but not for all four. One factor for each building was a combination of p/m-xylene, o-xylene and ethylbenzene. At least one factor for each building was identified that contained a broad mix of many species and constraints were used in PMF to modify the factors to resemble more closely the off-shift concentration profiles. PMF accepted the constraints with little decrease in model fit. Although the PMF model predicted the profiles of the off-shift samples, the percent of total emissions was under-predicted by the model versus the measured data.

Ballinger, Marcel Y.; Larson, Timothy V.

2014-12-01

213

Source apportionment of ambient volatile organic compounds in Beijing.  

PubMed

The ambient air quality standard for ozone is frequently exceeded in Beijing in summer and autumn. Source apportionments of volatile organic compounds (VOCs), which are precursors of ground-level ozone formation, can be helpful to the further study of tropospheric ozone formation. In this study, ambient concentrations of VOCs were continuously measured with a time resolution of 30 min in August 2005 in Beijing. By using positive matrix factorization (PMF), eight sources for the selected VOC species were extracted. Gasoline-related emissions (the combination of gasoline exhaust and gas vapor), petrochemicals, and liquefied petroleum gas (LPG) contributed 52, 20, and 11%, respectively, to total ambient VOCs. VOC emissions from natural gas (5%), painting (5%), diesel vehicles (3%), and biogenic emissions (2%) were also identified. The gasoline-related, petrochemical, and biogenic sources were estimated to be the major contributors to ozone formation potentials in Beijing. PMID:17626435

Song, Yu; Shao, Min; Liu, Ying; Lu, Sihua; Kuster, William; Goldan, Paul; Xie, Shaodong

2007-06-15

214

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

Microsoft Academic Search

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 U.S. Environmental

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

2012-01-01

215

Comparison of Seasonal Phenol and p-cresol Emissions from Ground Level Area Sources in a Dairy Operation in Central Texas  

Microsoft Academic Search

While 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 EPA method

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

2011-01-01

216

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

2010-11-01

217

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

218

Odor and VOC Emissions from Pan Frying of Mackerel at Three Stages: Raw, Well-Done, and Charred  

PubMed Central

Many classes of odorants and volatile organic compounds that are deleterious to our wellbeing can be emitted from diverse cooking activities. Once emitted, they can persist in our living space for varying durations. In this study, various volatile organic compounds released prior to and during the pan frying of fish (mackerel) were analyzed at three different cooking stages (stage 1 = raw (R), stage 2 = well-done (W), and stage 3 = overcooked/charred (O)). Generally, most volatile organic compounds recorded their highest concentration levels at stage 3 (O), e.g., 465 (trimethylamine) and 106 ppb (acetic acid). In contrast, at stage 2 (W), the lowest volatile organic compounds emissions were observed. The overall results of this study confirm that trimethylamine is identified as the strongest odorous compound, especially prior to cooking (stage 1 (R)) and during overcooking leading to charring (stage 3 (O)). As there is a paucity of research effort to measure odor intensities from pan frying of mackerel, this study will provide valuable information regarding the management of indoor air quality. PMID:25405596

Ahn, Jeong-Hyeon; Szulejko, Jan E.; Kim, Ki-Hyun; Kim, Yong-Hyun; Kim, Bo-Won

2014-01-01

219

Measuring Spatial Variability of Vapor Flux to Characterize Vadose-zone VOC Sources: Flow-cell Experiments  

SciTech Connect

A method termed vapor-phase tomography has recently been proposed to characterize the distribution of volatile organic contaminant mass in vadose-zone source areas, and to measure associated three-dimensional distributions of local contaminant mass discharge. The method is based on measuring the spatial variability of vapor flux, and thus inherent to its effectiveness is the premise that the magnitudes and temporal variability of vapor concentrations measured at different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell experiments was conducted to evaluate this premise. A well-defined source zone was created by injection and extraction of a non-reactive gas (SF6). Spatial and temporal concentration distributions obtained from the tests were compared to simulations produced with a mathematical model describing advective and diffusive transport. Tests were conducted to characterize both areal and vertical components of the application. Decreases in concentration over time were observed for monitoring points located on the opposite side of the source zone from the local–extraction point, whereas increases were observed for monitoring points located between the local–extraction point and the source zone. The results illustrate that comparison of temporal concentration profiles obtained at various monitoring points gives a general indication of the source location with respect to the extraction and monitoring points.

Mainhagu, Jon; Morrison, C.; Truex, Michael J.; Oostrom, Martinus; Brusseau, Mark

2014-10-20

220

Atmospheric process evaluation of mobile source emissions  

SciTech Connect

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

NONE

1995-07-01

221

Trends of VOC exposures among a nationally representative sample: Analysis of the NHANES 1988 through 2004 data sets  

NASA Astrophysics Data System (ADS)

Exposures to volatile organic compounds (VOCs) are ubiquitous due to emissions from personal, commercial and industrial products, but quantitative and representative information regarding long term exposure trends is lacking. This study characterizes trends from 1988 to 2004 for the 15 VOCs measured in blood in five cohorts of the National Health and Nutrition Examination Survey (NHANES), a large and representative sample of U.S. adults. Trends were evaluated at various percentiles using linear quantile regression (QR) models, which were adjusted for solvent-related occupations and cotinine levels. Most VOCs showed decreasing trends at all quantiles, e.g., median exposures declined by 2.5 (m,p-xylene) to 6.4 (tetrachloroethene) percent per year over the 15 year period. Trends varied by VOC and quantile, and were grouped into three patterns: similar decreases at all quantiles (including benzene, toluene); most rapid decreases at upper quantiles (ethylbenzene, m,p-xylene, o-xylene, styrene, chloroform, tetrachloroethene); and fastest declines at central quantiles (1,4-dichlorobenzene). These patterns reflect changes in exposure sources, e.g., upper-percentile exposures may result mostly from occupational exposure, while lower percentile exposures arise from general environmental sources. Both VOC emissions aggregated at the national level and VOC concentrations measured in ambient air also have declined substantially over the study period and are supportive of the exposure trends, although the NHANES data suggest the importance of indoor sources and personal activities on VOC exposures. While piecewise QR models suggest that exposures of several VOCs decreased little or any during the 1990's, followed by more rapid decreases from 1999 to 2004, questions are raised concerning the reliability of VOC data in several of the NHANES cohorts and its applicability as an exposure indicator, as demonstrated by the modest correlation between VOC levels in blood and personal air collected in the 1999/2000 cohort. Despite some limitations, the NHANES data provides a unique, long term and direct measurement of VOC exposures and trends.

Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

2011-09-01

222

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...

223

Shallow vs. Deep Fluid Sources In Hydrothermal Systems: New Insights From VOC Composition In Fumarolic Discharges And Soil Gases Of Yellowstone National Park (USA)  

NASA Astrophysics Data System (ADS)

The origin of non-methane volatile organic compounds (VOCs) in hydrothermal fluids is related to two distinct mechanisms regulated by different thermodynamic conditions (e.g. Des Marais et al., 1981; Mango, 2000; Capaccioni and Mangani, 2001): i) thermogenic reactions, such as catalytic reforming and/or thermal cracking, which proceed within the main reservoir at medium-to-high temperature (150-350°C) and reduced conditions; ii) biodegradation processes, occurring at relatively shallow depth, where uprising fluids have <150°C and suffer oxidizing conditions. According to these considerations, the main aim of the present investigation is to discriminate the different fluid sources feeding the hydrothermal system on the basis of the C2-C15 organic compounds in fumarolic discharges and soil gases collected at the Yellowstone National Park (USA). A total of 64 and 66 different species were identified in the gas discharges and in the soil gas samples, respectively. The composition of the organic gas fraction in the fumarolic fluids is relatively homogeneous, being dominated by C2-C6 alkanes (81 %) and showing relatively high concentrations of alkenes (13 %), aromatics (3.7 %) and cyclics (1.4 %). Differently, the relative percentages of alkanes and alkenes in the soil gas, where VOC abundances are about two orders of magnitude less abundant than those in the gas discharges, are significantly lower (64 and 6.8 %, respectively) and cyclics are absent. On the other hand, oxygenated species (17.8 %), aromatics (5.6 %) and Cl-bearing compounds (4.5 %) results to be enriched with respect to those measured in the gas vents. Such compositional differences are likely to be due to the bacterial activity in the soil that causes the production of ketones, esters, alcohols, aldehydes and organic acids from the C-H species (hydrocarbons sensu strictu). Organic acids, mainly constituted by ossalic acid and traces of tartaric, malonic citric and succinic ones, were also determined in the fumarolic condensates. This seems to indicate that biodegradation likely occurs even within the hydrothermal systems, since the production of low molecular mass organic acids is to be related to bacterial activity (Arnetoli et al., 2008 and references therein). S-bearing compounds are strongly controlled by the fS values and this would explain the relatively high concentrations of these species in the H2S-rich fumarolic discharges. As far as it concerns the relatively high abundance of halogenated compounds in the soil gases, it can be suggested that the origin of these species is likely to be related to atmospheric contribution. Actually, formation of Cl- bearing species from reactions between VOCs and Cl-rich fluids, such as those of the deep hydrothermal reservoir, is still matter of debate. Therefore, we may speculate that these compounds, characterized by chemical inertness, are added to the hydrothermal fluids from meteoric water recharging the system. References: Arnetoli, M., Montegrossi, G., Buccianti, A., Gonnelli, C., 2008. J. Agricol. Food Chem., 56, 789- 795. Capaccioni, B., Mangani, F., 2001. Earth Planet. Sci. Lett., 188, 543-555. Des Marais, D.J., Donchin, J.H., Truesdell, A.H., Nehring, N.L., 1981. Nature, 292, 826-828. Mango, F.D., 2000. Geochim. Cosmochim. Acta, 64, 1265-1277.

Tassi, F.; Capecchiacci, F.; Montegrossi, G.; Caliro, S.; Chiodini, G.; Vaselli, O.

2008-12-01

224

European emissions of atmospheric mercury from anthropogenic sources in 1995  

NASA Astrophysics Data System (ADS)

Estimates of atmospheric emissions of mercury from anthropogenic sources in Europe in 1995 are presented with the information on emissions of both total mercury and its major chemical and physical forms. The 1995 anthropogenic emissions of total emissions were estimated to be about 342 tonnes, a decrease of 45% compared to these emissions in 1990. Combustion of fuels, particularly coal has been the major source of anthropogenic emissions contributing to more than half to the total emissions. The emissions from coal combustion have not changed significantly over the past decade. Major decrease has been estimated for emissions from industrial processes, particularly the chlor-alkali production using the Hg cell process. In 1995 the European emissions of anthropogenic mercury contributed about 13% to the global emissions of this element from anthropogenic sources. The anthropogenic Hg emissions in Europe were still higher than the natural emissions in the region, estimated to be about 250- 300 tonnes per year. The accuracy of estimates of anthropogenic emissions of Hg in Europe in 1995 is considered to be between 25 and 50%. The most accurate seem to be the estimates for combustion sources, while the most incomplete data were collected and/or estimated for waste disposal. The emissions of gaseous elemental mercury contributed about 61% to the emissions of the total mercury, while the contribution of gaseous bivalent mercury and particulate mercury was 32 and 7%, respectively.

Pacyna, E. G.; Pacyna, J. M.; Pirrone, N.

225

IMPACTS OF CLIMATE CHANGE AND LAND COVER CHANGE ON BIOGENIC VOLATILE ORGANIC COMPOUNDS (BVOCS) EMISSIONS IN TEXAS  

EPA Science Inventory

Significant amounts of vegetation and forests in eastern and central Texas are the source of substantial emissions of volatile organic compounds (VOCs) which, when mixed with nitrogen oxides from anthropogenic sources, can lead to ozone formation. The biogenic emis...

226

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

227

Emission inventory of non-methane volatile organic compounds from anthropogenic sources in India  

NASA Astrophysics Data System (ADS)

This paper presents a new inventory of NMVOC emissions from anthropogenic sources in India for the year 2010. The main new element of this inventory, compared to previous work for India, is the use of new and more detailed data on solvent use sectors and oil production and distribution system. The results are presented at the national and state level for major sectors and VOC species. Finally, the annual emissions were spatially distributed at a fine resolution of 36 × 36 km2 using detailed spatial information. The total anthropogenic NMVOC emissions in India in 2010 were estimated at 9.81 Tg which is in the range of the estimates made in most other studies. The majority of emissions (60%) originated from residential combustion of biomass for cooking. Solvent use sectors and oil production and distribution contributed about 20% followed by transport (12%) and open burning of agricultural residues (7%). Specie-wise distribution shows highest contribution from alkenes and alkynes (38%), followed by alkanes (22%), and aromatics (16%).

Sharma, Sumit; Goel, Anju; Gupta, Divya; Kumar, Atul; Mishra, Arabinda; Kundu, Seema; Chatani, Satoru; Klimont, Zbigniew

2015-02-01

228

DEMONSTRATION OF EMERGING AREA SOURCE PREVENTION OPTIONS FORVOLATILE ORGANICS  

EPA Science Inventory

The paper describes, and gives the status of, a research program toreduce volatile organic compound (VOC) emissions from stationaryarea sources by developing, evaluating, and/or demonstratingpollution prevention options. he program includes two projects:(1) alternative coating ma...

229

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

230

40 CFR 52.2036 - 1990 base year emission inventory.  

Code of Federal Regulations, 2010 CFR

...nonattainment area. The VOC and NOX 1990 emissions...3 blast furnace are zero for both pollutants. The VOC and NOX 1990 emissions...based on the amount of solvent actually being recovered...adsorption system. Based on VOC emissions data...

2010-07-01

231

Constraining Emission Models of Luminous Blazar Sources  

SciTech Connect

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

Sikora, Marek; /Warsaw, Copernicus Astron. Ctr.; Stawarz, Lukasz; /Kipac, Menlo Park /Jagiellonian U., Astron. Observ. /SLAC; Moderski, Rafal; Nalewajko, Krzysztof; /Warsaw, Copernicus Astron. Ctr.; Madejski, Greg; /KIPAC, Menlo Park /SLAC

2009-10-30

232

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

233

Emissivity Tuned Emitter for RTPV Power Sources  

SciTech Connect

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

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

2012-03-01

234

Monoterpene emissions from bark beetle infested Engelmann spruce trees  

NASA Astrophysics Data System (ADS)

Bark beetle infestation impacts the health of coniferous forests, which are an important source of volatile organic compounds (VOCs) to the atmosphere. The types and amounts of VOCs emitted from forests can influence secondary organic aerosol (SOA) formation and impact overall air quality. In this initial work, the impact of bark beetle infestation on SOA precursors from Engelmann spruce is assessed. The VOCs emitted from the trunk of infested and healthy spruce trees were sampled using both sorbent traps and evacuated canisters that were analyzed by gas chromatography/mass spectroscopy. The samples from the infested spruce tree suggest a nine-fold enhancement in the total VOC emissions. The dominant VOCs in the infested spruce trees were 3-carene, ?-pinene, and ?-pinene. The increase observed in VOCs sampled at the trunk of the infested spruce was consistent with increases observed at infested lodgepole pine trunks. However, the types and amounts of VOCs emitted from Engelmann spruce and lodgepole pine are different, which suggests that additional measures of VOC emissions are needed to characterize the impact of bark beetle infestation on VOC emissions and SOA precursors.

Amin, Hardik S.; Russo, Rachel S.; Sive, Barkley; Richard Hoebeke, E.; Dodson, Craig; McCubbin, Ian B.; Gannet Hallar, A.; Huff Hartz, Kara E.

2013-06-01

235

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

236

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...

237

EMISSIONS FORECASTS FOR INDUSTRIAL PROCESS SOURCES  

EPA Science Inventory

The report gives national and regional air emissions forecasts from several sulfur oxide and nitrogen oxide (SOx and NOx) emissions control Process Model Projection Technique (PROMPT) test runs. PROMPT, one of a number of National Acid Precipitation Assessment Program emission fo...

238

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...

239

Silicon Nanoparticles: Source of Extended Red Emission?  

NASA Astrophysics Data System (ADS)

We have reviewed the characteristics of the extended red emission (ERE) as observed in many dusty astronomical environments, in particular, the diffuse interstellar medium of the Galaxy. The spectral nature and the photon conversion efficiency of the ERE identify the underlying process as highly efficient photoluminescence by an abundant component of interstellar dust. We have compared the photoluminescence properties of a variety of carbon- and silicon-based materials proposed as sources for the ERE with the observationally established constraints. We found that silicon nanoparticles provide the best match to the spectrum and to the efficiency requirement of the ERE. If present in interstellar space with an abundance sufficient to explain the intensity of the ERE, silicon nanoparticles will also contribute to the interstellar 9.7 ?m Si--O stretch feature in absorption, to the near- and mid-IR nonequilibrium thermal background radiation, and to the continuum extinction in the near- and far-UV. About 36% of the interstellar silicon that is depleted into the dust phase would be needed in the form of silicon nanoparticles, amounting to less than 5% of the interstellar dust mass. We propose that silicon nanoparticles form through the nucleation of SiO in oxygen-rich stellar mass outflows and that they represent an important small-grain component of the interstellar dust spectrum.

Witt, Adolf N.; Gordon, Karl D.; Furton, Douglas G.

1998-07-01

240

Proton emission from a laser ion source.  

PubMed

At intensities of the order of 10(10) W?cm(2), ns pulsed lasers can be employed to ablate solid bulk targets in order to produce high emission of ions at different charge state and kinetic energy. A special interest is devoted to the production of protons with controllable energy and current from a roto-translating target irradiated in repetition rate at 1-10 Hz by a Nd:Yag pulsed laser beam. Different hydrogenated targets based on polymers and hydrates were irradiated in high vacuum. Special nanostrucutres can be embedded in the polymers in order to modify the laser absorption properties and the amount of protons to be accelerated in the plasma. For example, carbon nanotubes may increase the laser absorption and the hydrogen absorption to generate high proton yields from the plasma. Metallic nanostrucutres may increase the electron density of the plasma and the kinetic energy of the accelerated protons. Ion collectors, ion energy analyzer, and mass spectrometers, used in time-of-flight configuration, were employed to characterize the ion beam properties. A comparison with traditional proton ion source is presented and discussed. PMID:22380289

Torrisi, L; Cavallaro, S; Cutroneo, M; Margarone, D; Gammino, S

2012-02-01

241

Proton emission from a laser ion source  

SciTech Connect

At intensities of the order of 10{sup 10} W/cm{sup 2}, ns pulsed lasers can be employed to ablate solid bulk targets in order to produce high emission of ions at different charge state and kinetic energy. A special interest is devoted to the production of protons with controllable energy and current from a roto-translating target irradiated in repetition rate at 1-10 Hz by a Nd:Yag pulsed laser beam. Different hydrogenated targets based on polymers and hydrates were irradiated in high vacuum. Special nanostrucutres can be embedded in the polymers in order to modify the laser absorption properties and the amount of protons to be accelerated in the plasma. For example, carbon nanotubes may increase the laser absorption and the hydrogen absorption to generate high proton yields from the plasma. Metallic nanostrucutres may increase the electron density of the plasma and the kinetic energy of the accelerated protons. Ion collectors, ion energy analyzer, and mass spectrometers, used in time-of-flight configuration, were employed to characterize the ion beam properties. A comparison with traditional proton ion source is presented and discussed.

Torrisi, L. [INFN-LNS Via S. Sofia 44, 95123 Catania (Italy); Dip.to di Fisica, Universita di Messina, V.le F.S. D'Alcontres 31, 98166 S. Agata, Messina (Italy); Cavallaro, S.; Gammino, S. [INFN-LNS Via S. Sofia 44, 95123 Catania (Italy); Cutroneo, M. [Dip.to di Fisica, Universita di Messina, V.le F.S. D'Alcontres 31, 98166 S. Agata, Messina (Italy); Margarone, D. [Institute of Physics, ASCR, v.v.i., 182 21 Prague 8 (Czech Republic)

2012-02-15

242

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

PubMed Central

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 bio-diesel 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 C9 to C16 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.

2015-01-01

243

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) a

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

2012-01-01

244

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

245

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

246

Area Source Emission Measurements Using EPA OTM 10  

EPA Science Inventory

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

247

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 ...

248

Receptor modeling of ambient VOC at Santiago, Chile  

NASA Astrophysics Data System (ADS)

Ambient VOC measured at a 1996 spring campaign at Santiago, Chile, have been analyzed using the receptor models UNMIX and Positive Matrix Factorization (PMF). The ambient campaign took place at two sites: a downtown site, close to major traffic emissions, and a residential site, downwind of major industrial sources and highways. At the downtown site the following source apportionments estimates were obtained: fuel evaporation, 29.7±5.6%; gasoline exhaust, 22.0±3.4%; diesel exhaust, 18.1±2.9%; biogenic, LPG and evaporative emissions, 18.0±3.4%, unexplained: 12%. At the residential site, the following source apportionment was obtained: transported gasoline exhaust, 31.2±4.1%; local gasoline exhaust, 25.5±4.0%; evaporative losses, 11.7±2.8%; LPG losses, 11.0±2.5%; biogenic emissions, 7.7±1.7%; diesel exhaust, 6.2±1.5%; unexplained, 7.7%. Thus, near 70% of ambient VOC impacts at both sites are due to mobile sources. The receptor analyses produced source profiles that had distinctive, dominant compounds; in addition, source contributions exhibited diurnal profiles that were consistent with ambient temperature and wind speed data, and the expected activity patterns within the city. Typical errors in the source contributions vary between 15% for the larger sources—like gasoline exhaust—and 25% for the smaller sources—like biogenic emissions. It was found that the number of factors given by the UNMIX model was a good starting point to refine the solution using PMF. Both models showed good performance at discriminating between source profiles that had similar compositions in subsets of common species, but PMF was able to find better, cleaner source profiles that did UNMIX. At both monitoring sites LPG losses appear mixed in with other source profiles, and this feature could not be solved by adding more source profiles in the analyses; this was likely due to a lack of C 3 measurements needed to better resolve an LPG source profile.

Jorquera, Héctor; Rappenglück, Bernhard

249

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

250

[Study on volatile organic compounds emission of straw combustion and management countermeasure in Wuhan city].  

PubMed

Straw combustion is an important anthropogenic source of volatile organic compounds (VOCs) in China. Emissions of VOCs from straw combustion significantly affect climate forcing and human health. A reliable estimation of VOCs emission from the source is the important prerequisite for emission impact assessment and control strategy in the urban or regional areas. VOCs emissions from straw combustion in Wuhan City and the districts were estimated by factor analysis method, which was based on the yield of major farm crops in the period of 2005-2011. Moreover, Cultivated-land Emission Intensity (Ie) and Regional Emission Intensity (Ir) were also calculated. VOCs Emissions from straw combustion in Wuhan City were (3,163 +/- 139) t in the period of 2005-2011; Ie and Ir was (1.52 +/- 0.06) t x km(-2) and (0.37 +/- 0.02) t x km(-2), respectively; Straw combustion of grain and oilseed crops was the main source of the emissions; 21 kinds of VOCs should be listed as the priority control pollutants for straw combustion in Wuhan City. The order of successively decreasing VOCs emission of districts in Wuhan City was Huangpi District, Xinzhou District, Jiangxia District, Caidian District, Hannan District, and Dongxihu District, the former 4 districts contributed to almost 90% VOCs emissions of the Wuhan City. Huangpi District, Xinzhou District, Jiangxia District, and Hannan District should be regarded as priority control areas of VOCs emission from straw combustion in Wuhan City. Much attention should be paid to Jiangxia District, which was nationally representative. Ie and Ir are important basic data for ecological risk assessment of some kind of pollutants emitted from straw combustion in the urban or regional areas. Furthermore, straw utilization model according to agricultural cyclic economy is a feasible way to cope with the environmental problem of straw combustion. PMID:24640888

Huang, Bi-Jie

2013-12-01

251

FUGITIVE EMISSION SOURCES AND BATCH OPERATIONS IN SYNTHETIC ORGANIC CHEMICAL PRODUCTION  

EPA Science Inventory

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 information presented in thi...

252

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

253

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

254

VOCs in industrial, urban and suburban neighborhoods, Part 1: Indoor and outdoor concentrations, variation, and risk drivers  

NASA Astrophysics Data System (ADS)

Information regarding indoor and ambient concentrations and exposures of volatile organic compounds (VOCs) is limited in terms of the number and types of compounds measured, the spatial and temporal variation of concentrations, and the significance of indoor and outdoor emission sources. This study characterizes a wide range of VOCs across three communities that represent a gradient of population density and industrial activity. Monitoring was conducted in two seasons inside and outside of 159 residences in industrial, urban and suburban cities located in southeast Michigan, USA. Passive samplers were deployed at each location, and analyzed for 98 compounds. Outdoors, 46 different VOCs were detected. Benzene, toluene, p, m-xylene and carbon tetrachloride had the highest concentrations (medians from 1 to 2 ?g m -3). Concentrations were elevated in winter in the suburban community, and levels were the highest in the industrial community. Indoors, 53 VOCs were detected, and benzene, toluene, p, m-xylene, n-heptane, ?-pinene and d-limonene had the highest concentrations (medians from 1 to 17 ?g m -3). Seasonal changes were small or inconsistent. Median indoor levels among the three communities generally followed outdoor rankings. Indoor/outdoor ratios varied from 1 to 10 for most compounds, but up to 100 for several compounds, e.g., d-limonene. Over a quarter of residences had benzene, naphthalene, chloroform and carbon tetrachloride at levels giving a chronic lifetime cancer risk above 10 -5 and sometimes much higher; outdoors, these compounds gave risks exceeding 10 -6. The study identifies a number of indoor emission sources associated with specific and sometimes very high VOC exposures, reports on several VOCs that have not been measured in previous indoor and outdoor studies, and shows the importance of both indoor and outdoor sources. Measured concentrations were at an intermediate level with respect to recent measurements elsewhere in the US, suggesting that study results are broadly representative.

Jia, Chunrong; Batterman, Stuart; Godwin, Christopher

255

40 CFR Table 1 to Subpart B of... - Volatile Organic Compound (VOC) Content Limits for Automobile Refinish Coatings  

Code of Federal Regulations, 2010 CFR

...Organic Compound (VOC) Content Limits for Automobile Refinish Coatings 1 Table 1 to Subpart...Organic Compound Emission Standards for Automobile Refinish Coatings Pt. 59, Subpt...Organic Compound (VOC) Content Limits for Automobile Refinish Coatings Coating...

2010-07-01

256

Gap-filling of VOC flux data for deriving annual budgets: Case study at a mountain meadow  

NASA Astrophysics Data System (ADS)

Although the biosphere is currently thought to be the main source for atmospheric volatile organic compounds (VOCs) longer time series of VOC measurements are barely available and the accuracy VOC modeling approaches still suffers from a lack of flux measurement data. However, long-term VOC flux data sets could provide a way to improve the quality of modeling approaches and make a first step towards a better VOC quantification. We used VOC flux data of methanol, acetone, acetaldehyde and the monoterpenes, which were measured by means of a proton transfer reaction - mass spectrometer PTR-MS utilising the disjunct eddy covariance method (vDEC) above an intensively managed mountain grassland in Stubai Valley (Austria), to compare the performance of four different gap filling approaches and to get complete annual time series of the VOCs for the years 2009 and 2011. Assuming a zero flux from the grassland during the winter period, when the meadow is usually covered by snow, the average cumulative VOC fluxes above the grassland show with 103 mg C m-2 in the year 2009 and 464 mg C m-2 in the year 2011 a high inter-annual variability. The gap filling using the filling method which performs best on the data introduced mean errors of 20 mg C m-2 in 2009 and 13 mg C m-2 in 2011. Methanol was with average cumulative emission fluxes of 375 mg C m-2 and 442 mg C m-2 during the year 2009 the main compound contributing to the VOC balance during both years. The cumulative fluxes of methanol using the four different gap-filling approaches agreed within a range smaller than 7 percent in 2009 and 2 percent in 2011. During the first year (2009) the cumulative deposition fluxes of monoterpenes (on average 317 mg C m-2) turned out to have also a big influence on the overall VOC balance (its cumulative flux variation depending on the used gap filling method was less than 10 percent). All other compounds showed fluxes which were below 10 percent of the methanol emission flux in 2009 while flux contribution of the non-methanol compounds was less than 5 percent of the total budget in 2011.

Bamberger, Ines; Hörtnagl, Lukas; Hansel, Armin; Wohlfahrt, Georg

2013-04-01

257

VOCs Speciation From Steam Boiler Stacks of Industries Located in Naucalpan  

NASA Astrophysics Data System (ADS)

Results of VOCs speciation from industrial steam boiler stacks located in Naucalpan are presented and discussed. This municipality is located north of the Metropolitan Zone of the Valley of Mexico (MZVM). Speciation of VOCs is important to generate information about sources of pollution, to update emission inventories, to study the dynamics of pollutants in the atmosphere, and to estimate possible risks of population exposure. This information is valuable for decision making on air pollution control strategies. Samples from 35 steam boilers form industries burning Diesel, LPG, or CNG were taken using the US-EPA Method 18. Selected samples from the use of different fuels were analyzed using gas chromatography and flame ionization detection (GC-FID) according to US-EPA protocol TO-14. The VOCs analyzed included alkanes of 9 carbons or less, alkenes of 7 carbons or less and aromatics (families of benzene). The results show consistency on the VOCs detected on Diesel samples. The main compounds found were 1- Butene+iButylene, m/p-Xylene, Ethane, Propene, Propane, Acetylene, 2Me-1Butene, and Toluene. The average concentrations of these compounds were in the range of 130 to 385 ppbC. The results of LPG samples did not show a definite pattern of VOCs, although light components predominate and, in some samples, Toluene and Xylene. These last components were not expected for industries reporting the use of LPG, perhaps due to the use of a combination of fuels and mistakes in the reports of fuel used at the time of sampling. The analysis of CNG samples show predominance of light VOCs, in the range of 90 to 300 ppbC. As in the case of LPG, some aromatics showed high concentrations in some samples analyzed perhaps due to the use of different fuels in the boiler. The results of this study are the first results of VOCs speciation obtained form exhaust gases from stacks of Mexican industries. The data reported are valuable to analyze emission inventories of VOCs and to better understand the dynamics of pollutants in the MZVM.

Mejia, G. M.; Tejeda, D. D.; Bremauntz, M. P.; Valdez, A.; Montufar, P. C.; Martinez, M. A.; Sierra, M. J.; Gonzalez, C. A.

2007-05-01

258

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...

259

MEASUREMENT OF PM-10 EMISSIONS FROM STATIONARY SOURCES  

EPA Science Inventory

Measurements of PM-10 particulate matter emissions from stationary sources were performed using two sampling approaches currently under development. PM-10 particulate matter is defined as all particles nominally 10 micrometers aerodynamic diameter and smaller. Aerodynamic inertia...

260

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...

261

Air Quality: Air Pollutants, SLAC Emissions Sources, and Regulatory Reference  

E-print Network

Air Quality: Air Pollutants, SLAC Emissions Sources, and Regulatory Reference Department: Chemical permit regulations are designed to track, record, and control air pollutants belonging to several on chemical classifications. This reference outlines major categories of air pollutants found at SLAC

Wechsler, Risa H.

262

AIR POLLUTION: GROUND-BASED SENSING OF SOURCE EMISSIONS  

EPA Science Inventory

Some types of gaseous pollution sources, particularly extended area industrial complexes and those producing hot combustion products, cannot be monitored adequately with conventional point sampling methods. To aid in characterizing emissions from and in developing remote sensing ...

263

EFFECTIVE SAMPLING TECHNIQUES FOR PARTICULATE EMISSIONS FROM ATYPICAL STATIONARY SOURCES  

EPA Science Inventory

Sampling techniques for measuring particulate emissions from four 'atypical' stationary source categories were developed and evaluated. The categories include low effluent velocity streams, extended dimensions, partially or totally unconfined flow, and saturated gas streams or ga...

264

Proton Transfer Reaction Time-of-Flight Mass Spectrometric (PTR-TOF-MS) determination of volatile organic compounds (VOCs) emitted from a biomass fire developed under stable nocturnal conditions  

NASA Astrophysics Data System (ADS)

Combustion of solid and liquid fuels is the largest source of potentially toxic volatile organic compounds (VOCs), which can strongly affect health and the physical and chemical properties of the atmosphere. Among combustion processes, biomass burning is one of the largest at global scale. We used a Proton Transfer Reaction “Time-of-Flight” Mass Spectrometer (PTR-TOF-MS), which couples high sensitivity with high mass resolution, for real-time detection of multiple VOCs emitted by burned hay and straw in a barn located near our measuring station. We detected 132 different organic ions directly attributable to VOCs emitted from the fire. Methanol, acetaldehyde, acetone, methyl vinyl ether (MVE), acetic acid and glycolaldehyde dominated the VOC mixture composition. The time-course of the 25 most abundant VOCs, representing ?85% of the whole mixture of VOCs, was associated with that of carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4) emissions. The strong linear relationship between the concentrations of pyrogenic VOC and of a reference species (i.e. CO) allowed us to compile a list of emission ratios (ERs) and emission factors (EFs), but values of ER (and EF) were overestimated due to the limited mixing of the gases under the stable (non-turbulent) nocturnal conditions. In addition to the 25 most abundant VOCs, chemical formula and concentrations of the residual, less abundant VOCs in the emitted mixture were also estimated by PTR-TOF-MS. Furthermore, the evolution of the complex combustion process was described on the basis of the diverse types of pyrogenic gases recorded.

Brilli, Federico; Gioli, Beniamino; Ciccioli, Paolo; Zona, Donatella; Loreto, Francesco; Janssens, Ivan A.; Ceulemans, Reinhart

2014-11-01

265

IRON AND STEEL PLANT OPEN SOURCE FUGITIVE EMISSION CONTROL EVALUATION  

EPA Science Inventory

The report gives results of measurements of the control efficiency of various techniques used to mitigate emissions from open dust sources in the iron and steel industry. Of estimated emissions of 88,800 tons/year suspended particulate in 1978 (based on a 10-plant survey), 70, 13...

266

IRON AND STEEL PLANT OPEN SOURCE FUGITIVE EMISSION EVALUATION  

EPA Science Inventory

The report gives results of field tests aimed at increasing the reliability of equations used to predict emission factors for open fugitive emission sources at iron and steel plants. The accuracy of previously developed equations is limited by the restricted number of actual test...

267

Global Emission of Mercury from Anthropogenic Sources in 1995  

Microsoft Academic Search

An estimate of the global emission of mercury from anthropogenicsources in 1995 has been prepared. Major emphasis is placed onemissions from stationary combustion sources, non-ferrous metalproduction, pig iron and steel production, cement production andwaste disposal. About three quarters of the total emission,estimated to be about 1900 tonnes, was from combustion of fuels, particularly coal combustion in China, India, and South

E. G. Pacyna; J. M. Pacyna

2002-01-01

268

Computerized tomography with X-ray, emission, and ultrasound sources  

Microsoft Academic Search

This paper reviews the major developments that have taken place during the last three years in imaging with computed tomography (CT) using X-ray, emission, and ultrasound sources. Space limitations have resulted in some selection of topics by the author. There are four major sections dealing with algorithms, X-ray CT, emission CT, and ultrosound CT. Since most of the currently used

A. C. Kak

1979-01-01

269

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...

270

CHARACTERIZATION OF EMISSIONS FROM COMBUSTION SOURCES: CONTROLLED STUDIES  

EPA Science Inventory

The 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 a...

271

Plant specific volatile organic compound emission factors from young and mature leaves of Mediterranean vegetation  

NASA Astrophysics Data System (ADS)

Terrestrial vegetation is the most important source of atmospheric volatile organic compounds (VOC) with significant influence on the chemistry and physics of the atmosphere. VOCs influence the oxidative capacity of the atmosphere and contribute to the formation and growth of secondary organic aerosols affecting cloud development and precipitation. The aim of our study was to investigate potential quantitative and qualitative differences in VOC emission patterns of young and mature leaves for nine typical Mediterranean plant species. The Mediterranean area was chosen due to its special diversity in VOC emitting plant species. Foliar isoprenoid emissions as well as emissions of oxygenated VOC like methanol and acetone were measured under standard light and temperature conditions during spring and summer 2008 at the CEFE-CNRS institute in Montpellier, France. A proton transfer reaction mass spectrometer (PTR-MS) was used for online measurement of VOCs. While PTR-MS is an excellent technique for fast chemical measurements it lacks specificity and compounds with the same mass cannot be distinguished. For this reason, cartridge samples were collected and afterwards analyzed with GC-FID. In parallel offline VOC analyses were performed with gas chromatography (GC) coupled to a mass spectrometer and flame ionization detector, enabling assignment of the observed PTR-MS mass to charge ratios (m/z) to specific identification based on the GC-FID retention times. Thus, combining the PTR-MS and GC-FID analyses enabled accurate and online identification of the VOCs emitted. The results emphasise that VOC emission is a developmentally regulated process and quantitative and qualitative variability is plant species specific. Leaf ontogeny clearly influenced not only the standard emission rate but also the VOC composition, with methanol being the major compound that contributes to the total VOC emissions in young leaves and maintaining or decreasing its contribution with maturity.

Bracho-Nunez, Araceli; Welter, Saskia; Staudt, Michael; Kesselmeier, Jürgen

2010-05-01

272

Paso del Norte ozone study VOC measurements, 1996  

SciTech Connect

The results of VOC determinations of ambient air samples collected at surface air quality monitoring sites and near sources of interest on the US and Mexican side of the border during six weeks of the 1996 Paso del Norte Ozone Study are reported. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites and analyzed by HPLC to quantify 13, C-1 to C-8 species. Whole air samples were collected in electro-polished stainless steel canisters which were returned to laboratory for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration capillary gas chromatography with flame ionization detection (gc-fid). Several sources were sampled: rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuel, petroleum refinery, and industrial manufacturing site. Spatial and temporal characteristics of VOC species concentrations and compositions are presented. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations recorded in the morning at three vehicle-dominated sites, two in Cuidad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cuidad Juarez, were the most abundant hydrocarbons.

Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.V.; Ramadan, A.B.

1999-01-01

273

Paso del Norte ozone study VOC measurements, 1996  

SciTech Connect

The results of VOC determinations of ambient air samples collected at surface air quality monitoring sites and near sources of interest on the US and Mexican side of the border during six weeks of the 1996 Paso del Norte Ozone Study are reported. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites and analyzed by HPLC to quantify 13, C-1 to C-8 species. Whole air samples were collected in electro-polished stainless steel canisters which were returned to laboratory for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration capillary gas chromatography with flame ionization detection (gc-fid). Several sources were sampled: rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuel, petroleum refinery, and industrial manufacturing site. Spatial and temporal characteristics of VOC species concentrations and compositions are presented. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations recorded in the morning at three vehicle-dominated sites, two in Cuidad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cuidad Juarez, were the most abundant hydrocarbons.

Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.V.; Ramadan, A.B.

1999-11-01

274

Diagnosis of air quality through observation and modeling of volatile organic compounds (VOCs) as pollution tracers  

NASA Astrophysics Data System (ADS)

This study used selected ambient volatile organic compounds (VOCs) as pollution tracers to study the effects of meteorology on air quality. A remote coastal site was chosen as a receptor to monitor pollutants transported upwind from urban traffic and industrial sources. Large concentration variability in VOC concentrations was observed at the coastal site due to rapid changes in meteorology, which caused periodic land-sea exchange of air masses. To assure the quality of the on-line measurements, uniform concentrations of chlorofluorocarbon-113 (CFC-113) were exploited as an internal check of the instrument's stability and the resulting data quality. A VOC speciated air quality model was employed to simulate both temporal and spatial distributions of VOC plumes. The model successfully captured the general features of the variations of toluene as a pollution tracer, which suggests that emissions and meteorology were reasonably well simulated in the model. Through validation by observation, the model can display both the temporal and spatial distribution of air pollutants in a dynamic manner. Thus, a more insightful understanding of how local air quality is affected by meteorology can be obtained.

Liu, Wen-Tzu; Hsieh, Hsin-Cheng; Chen, Sheng-Po; Chang, Julius S.; Lin, Neng-Huei; Chang, Chih-Chung; Wang, Jia-Lin

2012-08-01

275

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...

276

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

Code of Federal Regulations, 2010 CFR

... true PET and polystyrene affected sources-emissions control provisions. 63...STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards...1316 PET and polystyrene affected sources—emissions control provisions....

2010-07-01

277

High VOC loadings in biofilters - industrial applications  

SciTech Connect

To take pollution control and abatement into the next century, attitudes towards the environment and environmental regulations must change. There needs to be less emphasis on regulatory control, and greater opportunities for business to show an economic return on their investment in the environment. To provide this, the environmental industry must supply innovative, efficient and cost-effective solutions. Environmental biotechnologies have a proven track record for reliability, relatively low capital requirements, low operation and maintenance costs and low energy requirements. These past applications and experiences with biotechnologies can provide a solid foundation for substantial improvement in air pollution control systems. Bio-Reaction Industries, Inc. has developed a modular vapor-phase biofilter which is capable of treating extremely high concentrations of volatile organic compounds (VOCs) in low air volumes. Applications described include, but are not limited to: point-source industrial process air streams, storage tank and other vent emissions, and on-site treatment of aerosol cans and solvent-laden solid wastes such as rags, paint solids and still bottoms.

Stewart, W.C.; Thom, R.R. [Bio-Reaction Industries, Inc., Tualatin, OR (United States)

1997-12-31

278

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

279

Effect of low emission sources on air quality in Cracow  

SciTech Connect

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

Nedoma, J. [EKOPOL Environmental Engineering Studies and Design Office, Co. Ltd., Cracow (Poland)

1995-12-31

280

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

281

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

282

WORKSHOP ON SOURCE EMISSION AND AMBIENT AIR MONITORING OF MERCURY  

EPA Science Inventory

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

283

Contribution of unresolved point sources to the galactic diffuse emission  

E-print Network

The detection by the HESS atmospheric Cherenkov telescope of fifteen new sources from the Galactic plane makes it possible to estimate the contribution of unresolved point sources like those detected by HESS to the diffuse Galactic emission measured by EGRET and recently at higher energies by the Milagro Collaboration. Assuming that HESS sources have all the same intrinsic luminosity, the contribution of this new source population can account for most of the Milagro $\\gamma$-ray emission at TeV energies and between 10 and 20 per cent of EGRET diffuse Galactic $\\gamma$-ray emission for energies bigger than 10 GeV. Also, by combining the HESS and the Milagro results, constraints can be put on the distribution and the luminosities of gamma ray emitters in the Galaxy.

Casanova, S; Casanova, Sabrina; Dingus, Brenda L.

2006-01-01

284

Contribution of unresolved point sources to the galactic diffuse emission  

E-print Network

The detection by the HESS atmospheric Cherenkov telescope of fifteen new sources from the Galactic plane makes it possible to estimate the contribution of unresolved point sources like those detected by HESS to the diffuse Galactic emission measured by EGRET and recently at higher energies by the Milagro Collaboration. Assuming that HESS sources have all the same intrinsic luminosity, the contribution of this new source population can account for most of the Milagro $\\gamma$-ray emission at TeV energies and between 10 and 20 per cent of EGRET diffuse Galactic $\\gamma$-ray emission for energies bigger than 10 GeV. Also, by combining the HESS and the Milagro results, constraints can be put on the distribution and the luminosities of gamma ray emitters in the Galaxy.

Sabrina Casanova; Brenda L. Dingus

2006-09-12

285

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

286

Noise source emissions, Davis Canyon site, Utah  

SciTech Connect

This report has been prepared for the purpose of documenting the development of the data provided to the Repository Project Management (RPM) organization. The data provided encompass all phases of activity, from site preparation through the exploratory shaft facility (ESF) and repository construction and operation, and decommissioning. Noise environments expected from construction and operation of transportation corridors associated with the activity were also modeled. The data for the construction of transportation corridors were provided by Bechtel National, Inc. Use of the quietest equipment available within the proven state of the art was assumed, as was the use of acoustical enclosures to the extent practical. The programmatic assumptions are based on the noise-sensitive nature of the Canyonlands National Park. Another feature of the data is the use of 1/3-octave-band rather than 1/1-octave-band resolution of emission spectra. This was done to permit evaluation of audibility of sounds reaching the park.

Not Available

1987-07-01

287

Effect of wind tunnel air velocity on VOC flux rates from CAFO manure and wastewater  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wind tunnels and flux chambers are often used to estimate volatile organic compound (VOC) emissions 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 ...

288

Uptake of VOC by sunflower  

NASA Astrophysics Data System (ADS)

To study potential VOC uptake by plants we exposed sunflower (Helianthus annuus) to different VOC in continuously stirred tank reactors. For many VOC like methanol, ethanol, acetone, methylvinylketone, isoprene or limonene no uptake was detectable within the accuracy of our analytic set up. Other VOC like hexanal, octanal, (E)-3-hexenol and nopinone were taken up by sunflower. The uptake was related to stomatal aperture. Obviously, these VOC enter the plants through stomata. In case of hexanal, octanal, and (E)-3-hexenol the uptake was only limited by stomatal aperture implying that these VOC are rapidly metabolised. For nopinone the uptake seems to be limited by a slow metabolization. Estimations of deposition velocities showed that dry deposition of these compounds cannot be neglected as sink if diffusion through stomata is the limiting step for dry deposition. In such cases the lifetime with respect to dry deposiotion is comparable to the lifetime with respect to oxidation by hydroxyl radicals.

Folkers, A.; Miebach, M.; Kleist, E.; Wildt, J.

2003-04-01

289

METHOD FOR SEPARATING VOLATILE ORGANIC CARBON FROM 0.1 M3 OF AIR TO IDENTIFY SOURCES OF OZONE PRECURSORS VIA ISOTOPE (14C) MEASUREMENTS  

EPA Science Inventory

Atmospheric non-methane volatile organic compounds (VOCS) are known to play an important role in urban ozone formation during the summer. o respond to the need for a direct measure of VOC source contributions from biogenic (14C/12C=10-12) and fossil fuel (14C/12C=O) emissions, a ...

290

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.

291

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

PubMed Central

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

Sanchez, Marciano; Karnae, Saritha; John, Kuruvilla

2008-01-01

292

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

Code of Federal Regulations, 2011 CFR

...Hazardous Air Pollutants for Secondary Aluminum Production Emission Standards and Operating...standards for each type of source. (b) Aluminum scrap shredder. On and after the compliance...1501, the owner or operator of an aluminum scrap shredder at a secondary...

2011-07-01

293

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

Code of Federal Regulations, 2013 CFR

...Hazardous Air Pollutants for Secondary Aluminum Production Emission Standards and Operating...standards for each type of source. (b) Aluminum scrap shredder. On and after the compliance...1501, the owner or operator of an aluminum scrap shredder at a secondary...

2013-07-01

294

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

...Hazardous Air Pollutants for Secondary Aluminum Production Emission Standards and Operating...standards for each type of source. (b) Aluminum scrap shredder. On and after the compliance...1501, the owner or operator of an aluminum scrap shredder at a secondary...

2014-07-01

295

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

Code of Federal Regulations, 2012 CFR

...Hazardous Air Pollutants for Secondary Aluminum Production Emission Standards and Operating...standards for each type of source. (b) Aluminum scrap shredder. On and after the compliance...1501, the owner or operator of an aluminum scrap shredder at a secondary...

2012-07-01

296

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

297

ON-ROAD VEHICLE EMISSIONS: USA STUDIES  

EPA Science Inventory

Several recent events in mobile sources emissions measurements have caused a major reassessment in the amounts of volatile organic compounds (VOC) and carbon monoxide (CO) in the ambient air attributed to mobile sources. hese include the comparison of real world in-use vehicle em...

298

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

299

Low VOC drying of lumber and wood panel products. Progress report No. 5  

SciTech Connect

This progress report summarizes three accomplishments in a study of low volatile organic compound (VOC) drying of lumber and wood panel products. A mathematical model for predicting moisture emissions from particle was constructed and is being extended to VOCs. VOCs emissions from drying boards show that VOCs appear to be evenly released from all surfaces. Preliminary results from monthly analyses of loblolly pines indicate that resin acids appear to decrease between March to August, and that no consistent trends are apparent for terpenes. 3 refs., 13 figs., 1 tab.

Wild, P.; Yan, Hui; Banerjee, S. [and others

1997-10-01

300

Outer heliospheric radio emissions. I - Constraints on emission processes and the source region  

NASA Technical Reports Server (NTRS)

Observations by Voyager 1 and 2 of LF radio emissions near 2 and 3 kHz during the interval 1983-1987 while at heliocentric distances from 15 to 27 AU and 11 to 20 AU, respectively, are reported. Constraints on the emission processes and source characteristics are discussed. Minimum Langmuir wave electric fields in the source region, based solely on the kinematics of the radiation processes, lie in the range 1-100 micro-V/m for nominal source and electron beam parameters. Path lengths for fundamental and harmonic emission processes are calculated. The observed levels of radiation can be produced in path lengths and source dimensions smaller than 1 AU provided the participating Langmuir waves have effective temperatures of about 10 exp 17 K. Previous source models for the radiation are discussed.

Cairns, Iver H.; Gurnett, Donald A.

1992-01-01

301

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. PMID:24363783

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

2013-01-01

302

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

303

Geogenic and atmospheric sources for volatile organic compounds in fumarolic emissions from Mt. Etna and Vulcano Island (Sicily, Italy)  

NASA Astrophysics Data System (ADS)

In this paper, fluid source(s) and processes controlling the chemical composition of volatile organic compounds (VOCs) in gas discharges from Mt. Etna and Vulcano Island (Sicily, Italy) were investigated. The main composition of the Etnean and Volcano gas emissions is produced by mixing, to various degrees, of magmatic and hydrothermal components. VOCs are dominated by alkanes, alkenes and aromatics, with minor, though significant, concentrations of O-, S- and Cl(F)-substituted compounds. The main mechanism for the production of alkanes is likely related to pyrolysis of organic-matter-bearing sediments that interact with the ascending magmatic fluids. Alkanes are then converted to alkene and aromatic compounds via catalytic reactions (dehydrogenation and dehydroaromatization, respectively). Nevertheless, an abiogenic origin for the light hydrocarbons cannot be ruled out. Oxidative processes of hydrocarbons at relatively high temperatures and oxidizing conditions, typical of these volcanic-hydrothermal fluids, may explain the production of alcohols, esters, aldehydes, as well as O- and S-bearing heterocycles. By comparing the concentrations of hydrochlorofluorocarbons (HCFCs) in the fumarolic discharges with respect to those of background air, it is possible to highlight that they have a geogenic origin likely due to halogenation of both methane and alkenes. Finally, chlorofluorocarbon (CFC) abundances appear to be consistent with background air, although the strong air contamination that affects the Mt. Etna fumaroles may mask a possible geogenic contribution for these compounds. On the other hand, no CFCs were detected in the Vulcano gases, which are characterized by low air contribution. Nevertheless, a geogenic source for these compounds cannot be excluded on the basis of the present data.

Tassi, F.; Capecchiacci, F.; Cabassi, J.; Calabrese, S.; Vaselli, O.; Rouwet, D.; Pecoraino, G.; Chiodini, G.

2012-09-01

304

CO2 EMISSIONS FROM BIOENERGY AND OTHER BIOGENIC SOURCES IN STATIONARY SOURCES  

EPA Science Inventory

On January 12, 2011, EPA announced a series of steps to address the treatment of biogenic CO2 emissions from stationary sources, including a detailed study of the scientific and technical issues associated with accounting for biogenic carbon dioxide emissions from stationary sour...

305

EMISSIONS ASSESSMENT OF CONVENTIONAL STATIONARY SYSTEMS: VOLUME III. EXTERNAL COMBUSTION SOURCES FOR ELECTRICITY GENERATION  

EPA Science Inventory

The report characterizes multimedia emissions from external combustion sources for electricity generation. Study results indicate that external combustion sources for electricity generation contribute significantly to the nationwide emissions burden. Flue gas emissions of NOx, SO...

306

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

307

Fourier transform atomic emission studies using a glow discharge as the emission source  

NASA Astrophysics Data System (ADS)

The glow discharge (GD) is investigated as a possible atomic emission source for Fourier transform atomic emission spectroscopy (FT-AES). Noise power spectra are presented to demonstrate that GD emission is primarily characterized by photon noise, although a drift noise component exists at extremely low frequencies. The photon noise character is important, since photon noise limited sources are expected to outperform source flicker noise limited sources in terms of measurement precision. The implementation of bandpass restriction and dual channel subtractive noise cancellation as possible means of improving measurement precision are also presented. In both cases, the improvements were found to be minimal, a fact attributed to the probable suitability of the GD for FT-AES.

Winchester, Michael R.; Travis, John C.; Salit, Marc L.

1993-09-01

308

Fundamental mass transfer modeling of emission of volatile organic compounds from building materials  

NASA Astrophysics Data System (ADS)

In this study, a mass transfer theory based model is presented for characterizing the VOC emissions from building materials. A 3-D diffusion model is developed to describe the emissions of volatile organic compounds (VOCs) from individual sources. Then the formulation is extended to include the emissions from composite sources (system comprising an assemblage of individual sources). The key parameters for the model (The diffusion coefficient of the VOC in the source material D, and the equilibrium partition coefficient k e) were determined independently (model parameters are determined without the use of chamber emission data). This procedure eliminated to a large extent the need for emission testing using environmental chambers, which is costly, time consuming, and may be subject to confounding sink effects. An experimental method is developed and implemented to measure directly the internal diffusion (D) and partition coefficients ( ke). The use of the method is illustrated for three types of VOC's: (i) Aliphatic Hydrocarbons, (ii) Aromatic Hydrocarbons and ( iii) Aldehydes, through typical dry building materials (carpet, plywood, particleboard, vinyl floor tile, gypsum board, sub-floor tile and OSB). Then correlations for predicting D and ke based solely on commonly available properties such as molecular weight and vapour pressure were proposed for each product and type of VOC. These correlations can be used to estimate the D and ke when direct measurement data are not available, and thus facilitate the prediction of VOC emissions from the building materials using mass transfer theory. The VOC emissions from a sub-floor material (made of the recycled automobile tires), and a particleboard are measured and predicted. Finally, a mathematical model to predict the diffusion coefficient through complex sources (floor adhesive) as a function of time was developed. Then this model (for diffusion coefficient in complex sources) was used to predict the emission rate from material system (namely, substrate//glue//vinyl tile).

Bodalal, Awad Saad

309

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...

310

DETECTING SMALL LOW EMISSION RADIATING SOURCES Moritz Allmaras  

E-print Network

security. A technique of detecting such sources using Compton type cameras is developed, which is shown of the Department of Homeland Security is to prevent smuggling of weapon-grade nuclear materials (e.g., [24 particles. For instance, the -cameras most commonly used in SPECT (Single Photon Emission Computed

311

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...

312

SENSITIVITY OF RADM TO POINT SOURCE EMISSIONS PROCESSING  

EPA Science Inventory

The Regional Acid Deposition Model (RADM) and associated Engineering Model have been developed to study episodic source-receptor relationships on a regional scale. he RADM includes transport, chemical transformation, and deposition processes as well as input of emissions into the...

313

Enhanced directed emission from metamaterial based radiation source  

Microsoft Academic Search

The enhanced directed emission from a metasurface which is illuminated at its resonance frequency by a dipole source is experimentally demonstrated. The metasurface consists of two cutwire layers and a continuous wire layer in between, which exhibits strong magnetic dipole resonance under excitation normal to the plane. The scanned near-field patterns show the confinement of the field in the presence

Elena Saenz; Kaan Guven; Ekmel Ozbay; Iñigo Ederra; Ramon Gonzalo

2008-01-01

314

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...

315

Pcb emissions from stationary sources: a theoretical study. Final report  

Microsoft Academic Search

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 concern caused by tentative identification of PCB isomers in ash and flyash from a utility steam generating

Knieriem; H. Jr

1976-01-01

316

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...

317

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...

318

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

Code of Federal Regulations, 2010 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...

2010-07-01

319

Source characteristics of Jovian narrow-band kilometric radio emissions  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

320

Modeling unsteady-state VOC transport in simulated waste drums. Revision 1  

SciTech Connect

This report is a revision of an EG&G Idaho informal report originally titled Modeling VOC Transport in Simulated Waste Drums. 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 permeability had been measured.

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

1994-01-01

321

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

322

Past and Future Changes in Biogenic Volatile Organic Compound Emissions Simulated with a Global Dynamic Vegetation Model  

NASA Astrophysics Data System (ADS)

The terrestrial biosphere is an essential component of the surface-atmosphere interactions, emitting highly reactive compounds such as isoprene, monoterpenes, methanol and other alcohols, acetone, or aldehydes, in the troposphere. Those volatile organic compounds (VOC) are strongly involved in tropospheric chemistry, and participate not only to gas phase reactions but also to particulate formation. Moreover, biogenic VOC emissions are very sensitive to environmental conditions (temperature, radiation, vegetation type) and could thus be significantly affected by climate and vegetation distribution changes. Based on the interactive global biogenic emission and dynamic vegetation model ORCHIDEE, we investigate the evolution of biogenic VOC emissions in four scenarios: the Last Glacial Maximum (21,000 years BP), the preindustrial (1850s), present-day (1990s) and the future (2100). The combined effects of foliar expansion, climate change and ecosystem redistribution has a large impact on biogenic emissions. We estimate that total biogenic VOC emissions increase from 331 TgC/yr at the LGM to 702 TgC/yr at the preindustrial, 725 TgC/yr at present-day and to 1251 TgC/yr under future conditions. Furthermore, it is important to notice that if the tropics remain a major source region, a substantial decrease in VOC emissions is calculated over Amazonia for 2100 due to the recession of tropical forests in response to climate change. The northern hemisphere becomes a significant source of VOC in the future and globally, emissions increase by 27% for isoprene and 51% for monoterpenes compared to the present.

Lathiere, J.; Hauglustaine, D.; de Noblet-Ducoudre, N.; Krinner, G.; Folberth, G.

2005-12-01

323

Experimental and numerical VOC concentration field analysis from flooring material in a ventilated room  

E-print Network

Experimental and numerical VOC concentration field analysis from flooring material in a ventilated in a ventilated room. A field study has been conducted in the CSTB experimental house MARIA. Measurements were ventilation conditions. -Pinene was selected as tracer from flooring VOC emissions. Velocity and temperature

Paris-Sud XI, Université de

324

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

325

Acoustic emission source mechanisms for steel bridge material  

NASA Astrophysics Data System (ADS)

Over the past twenty years acoustic emission (AE) has been studied for applications to the structural health monitoring (SHM) of metallic structures. The success of AE for prognosis of in-service steel bridges depends on the reliability of the received AE signals. The emphasis of this paper is on the characterization of acoustic emission source mechanisms for ASTM A572 grade 50 steel. The source characterization was aided by Digital Imaging Correlation (DIC) and Scanning Electronic Microscopy (SEM). The results indicate that both ductile and brittle mechanisms can produce AE during fatigue crack growth in the steel. However, the fracture mechanisms are predominately ductile. A key preliminary finding is that fatigue crack extension does not generally produce AE events in the early stage of fatigue crack growth for the steel bridge material investigated.

Hossain, M.; Yu, J.; Ziehl, P.; Caicedo, J.; Matta, F.; Guo, S.; Sutton, M.

2013-01-01

326

UV emissions from low energy artificial light sources.  

PubMed

Energy efficient light sources have been introduced across Europe and many other countries world wide. The most common of these is the Compact Fluorescent Lamp (CFL), which has been shown to emit ultraviolet (UV) radiation. Light Emitting Diodes (LEDs) are an alternative technology that has minimal UV emissions. This brief review summarises the different energy efficient light sources available on the market and compares the UV levels and the subsequent effects on the skin of normal individuals and those who suffer from photodermatoses. PMID:24313558

Fenton, Leona; Moseley, Harry

2014-01-01

327

Estimation of emissions from charcoal lighter fluid and review of alternatives. Final report  

SciTech Connect

The report gives results of an evaluation of emissions of volatile organic compounds (VOCs) from charcoal lighter fluid, a consumer product consisting entirely of volatile constituents. An estimated 46,250 tons (42,000 Mg) of charcoal lighter fluid is used in the U.S. each year. VOCs contribute to the formation of ozone; therefore, the ozone nonattainment issue has focused attention on VOCs emitted from many sources. VOCs are emitted when charcoal lighter fluid is used, but these emissions are difficult to quantify. Evaporative VOC losses occur from the lighter fluid prior to ignition, and combustion VOC losses occur from burning lighter-fluid-soaked charcoal briquettes. This study evaluates tests conducted to date on charcoal lighter fluid emissions. The information is most complete for evaporative VOC losses. The estimates vary greatly, however, based on the length of time between application of the lighter fluid and ignition. The limited tests conducted to date have not distinguished lighter fluid from charcoal-briquette combustion emissions.

Campbell, D.L.; Stockton, M.B.

1990-01-01

328

Source characteristics of Jovian narrow-band kilometric radio emissions  

Microsoft Academic Search

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

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

1993-01-01

329

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

330

Carbon nanotube based field emission X-ray sources  

NASA Astrophysics Data System (ADS)

This dissertation describes the development of field emission (FE) x-ray sources with a carbon-nanotube (CNT) cathode. Field emission x-rays have advantages over conventional x-rays by replacing the thermionic cathode with a cold cathode so that electrons are emitted at room temperature and emission is voltage controllable. CNTs are found to be excellent electron emitters with low threshold fields and high current density which makes them ideal for generate field emission x-rays. Macroscopic CNT cold cathodes are prepared and the parameters to tune their field emission properties are studied: structure and morphology of CNT cathodes, temperature as well as electronic work function of CNT. Macroscopic CNT cathodes with optimized performance are chosen to build a high-resolution x-ray imaging system. The system can readily generate x-ray radiation with continuous variation of temporal resolution up to nanoseconds and spatial resolution down to 10 micron. Its potential applications for dynamic x-ray imaging and micro-computed tomography are also demonstrated. The performance characteristics of this compact and versatile system are promising for non-destructive testing and for non-invasive small-animal imaging for biomedical research.

Cheng, Yuan

331

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

PubMed

A 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 means for diagnosing and confirming a failure of the insulating coating of the ion source RF antenna which is immersed in the plasma. Emissions of composition elements of the antenna coating material, Na emission being the most significant, drastically elevate to signal a failure when it happens. Plasma spectra of the developmental ion source with an AlN (aluminum nitrite) chamber and an external RF antenna are also briefly discussed. PMID:24593570

Han, B X; Welton, R F; Murray, S N; Pennisi, T R; Santana, M; Stockli, M P

2014-02-01

332

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

333

Treatment of munitions manufacturing airborne VOC`s by biofiltration  

SciTech Connect

The US Army Construction Engineering Research Laboratory contracted MBI International to perform a biofiltration study of industrial waste gas streams. Phase I of the study was a laboratory investigation of the treatability of a specific gas stream. The laboratory study was concluded in September, 1995. Phase II was the design, placement and operation of a full-scale biofilter. The project was completed in August, 1996. The specific gas stream originates from a munitions drying operation at the Olin Chemical Company, Lake City, AAP, Independence, MO. The production line is a blank bullet coating operation in the production line, slats of blank ammunition are inverted and dipped into a coating material to seal the shell tips. The slats are then righted and moved into a drying box. The major solvent in the coating is ethyl acetate (70%) with about 30% of other solvent, such as, xylene and low molecular weight alcohols. The coating is thinned 50% with ethyl acetate, such that ethyl acetate represents more than 90% of the VOC load. The concentration of VOC`s is 400 ug/L at an air flow rate of 1000 ft{sup 3}/min. Laboratory results were collected on six test biofilter columns (15L). Steady state operations over a wide range of VOC loads were studied. The biofilters consistently destroyed 90-95% of the VOC`s. Square-wave dynamic loading cycles were studied to represent shift changes at the production facility. At high loadings, the biofilter performed well. At low organic loadings at applications of 5 hr/day of the gas stream, the filters required a small supplement of glucose to maintain column efficacy. A 1000 cubic foot bed volume, engineered media, biofilter was installed at Lake City AAP in January, 1996. The unit consists of a skid-mounted, class-1 division-1 explosion proof design including the blower package, biofilter media, nutrient addition, and automated VOC monitoring with PID. The unit was monitored for six months.

Severin, B.F.; Neilson, L.M. [MBI International, Lansing, MI (United States); Kim, B.J. [Army Construction Engineering Research Lab., Champaign, IL (United States)

1997-12-31

334

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

NASA Astrophysics Data System (ADS)

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

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

335

VOCs measurement at Tomakomai research forest, Japan  

NASA Astrophysics Data System (ADS)

Intensive atmospheric field measurement was held on at Tomakomai research forest during summer in 2006. The purpose of the measurement was to observe the atmospheric chemistry at enhanced biogenic emission area influenced by urban polluted air, especially in the view point of OH reactivity. Tomakomai research forest is located by city area. Several VOCs including both anthropogenic and biogenic VOC were observed by different methods, canister grab sampling (GC-FID, and GC-MS), on site GC-FID measurement, and PTR-MS measurement. Also general atmospheric species (O3, CO, NOx, SO2) were observed. From the results of anthropogenic species, influence of urban air nearby and of long-range transport was both expected. Also influence of volcano was expected by SO2. The comparison of biogenic VOCs by different methods showed good agreement. The problem during the canister storage was not observed. Observed terpenes (alfa-pinene, camphene, limonene, and beta-pinene) showed higher concentration during night and lower during daytime. The maximum concentration was about 900 ppt as the sum of terpenes. On the other hand, isoprene showed higher concentration during daytime and low during night. The maximum concentration was about 1.5 ppb. There concentrations were not high as expected as a forest atmosphere. Since the temperature during the campaign was 27 C at maximum, the emission from the plants was not very enhanced. The comparison with directly observed OH reactivity and calculated OH reactivity from various species showed some difference during daytime. The difference has good correlation between isoprene. The difference would be caused by unmeasured species, which should have similar concentration variation as isoprene. The signal of m/z=71 observed by PTR-MS, corresponding to VMK and MACR, showed quite similar variation of isoprene. They ware produced by the oxidation of isoprene. Even if their very high concentrations were assumed, the difference of the OH reactivity can not be explained.

Kato, S.; Kajii, Y.; Nishida, S.; Tajiama, Y.; Okazaki, H.; Matsunaga, S.; Greenberg, J.; Guenther, A.; Hiura, T.; Ishii, K.

2007-12-01

336

The GEIA global gridded inventory of anthropogenic VOCs  

SciTech Connect

Modeling assessments of the atmospheric chemistry, air quality and climatic conditions of the past, present and future require as input inventories of emissions of the appropriate chemical species constructed on appropriate spatial and temporal scales. The task of the Global Emissions Inventories Activity (GEIA) of the International Global Atmospheric Chemistry Project (IGAC) is the production of global inventories suitable for a range of research applications. Current GEIA programs are generally based on addressing emissions by species; an international working group of interested participants cooperates in the work needed to compile each inventory. The work of the GEIA program addressing the compilation of a global inventory of anthropogenic emissions of Volatile Organic Compounds (VOCs) gridded with 1{degree} resolution is presented. Past studies were used to identify anthropogenic activities according to their contribution to global VOC emissions, based on results of these initial studies, activity and species groupings for emissions reporting have been selected. Current status of the work of the committee is discussed. Detailed information on available activity rates, emission factors, and speciation profiles for each defined sector is being compiled. Links to investigators working on the compilation of VOC emissions on a regional level have been established.

Benkovitz, C.M. [Brookhaven National Lab., Upton, NY (United States); Berdowski, J.J.M.; Veldt, C. [IMW-TNO, Delft (Netherlands)

1995-04-01

337

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

338

GENERAL DESIGN STUDY OF PILOT VOC CONTROL UNITS  

EPA Science Inventory

The Industrial Environmental Research Laboratory (IERL), in support of the Office of Air Quality Planning and Standards Volatile Organic Compounds (VOC) Program, has established a project for design, construction and operation of four pilot emission control units which will be tr...

339

Dispersion of buoyant emissions from low level sources in urban areas: water channel modelling  

E-print Network

sources in urban areas: water channel modelling’, Int. J.level sources in urban areas: water channel modelling Sammodelling the dispersion from low level buoyant sources: Dispersion of buoyant emissions from low level sources in urban

Pournazeri, Sam; Schulte, Nico; Tan, Si; Princevac, Marko; Venkatram, Akula

2013-01-01

340

40 CFR 63.1356 - Sources with multiple emissions limit or monitoring requirements.  

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emissions limit or monitoring requirements....

2014-07-01

341

40 CFR 63.1356 - Sources with multiple emission limits or monitoring requirements.  

Code of Federal Regulations, 2012 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emission limits or monitoring requirements....

2012-07-01

342

40 CFR 63.1356 - Sources with multiple emissions limit or monitoring requirements.  

Code of Federal Regulations, 2013 CFR

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emissions limit or monitoring requirements....

2013-07-01

343

40 CFR 63.1356 - Sources with multiple emission limits or monitoring requirements.  

Code of Federal Regulations, 2011 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emission limits or monitoring requirements....

2011-07-01

344

40 CFR Table 1 to Subpart Xxxx of... - Emission Limits for Tire Production Affected Sources  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Emission Limits for Tire Production Affected Sources 1 Table...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Pt. 63, Subpt. XXXX...XXXX of Part 63—Emission Limits for Tire Production Affected Sources As...

2010-07-01

345

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

Code of Federal Regulations, 2010 CFR

... true What emission limits must I meet for tire production affected sources? 63.5984 Section...Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Emission Limits for Tire Production Affected Sources § 63.5984...

2010-07-01

346

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...

347

Reduction of odorous VOC in phenolics solutions and swine manure slurry using soybean peroxidase and hydrogen peroxide  

Technology Transfer Automated Retrieval System (TEKTRAN)

A research project was conducted to evaluate the efficacy of low-activity soybean peroxidase (SBP; 0.75 U/mg) and H2O2 for reducing emissions of odorous volatile organic compounds (VOC) from standard solutions (phenol and 4-methylphenol; 1 mM each) and swine manure slurry. VOC emissions were measu...

348

Locating and estimating air emissions from sources of chlorobenzenes (revised March 1994). Final report  

SciTech Connect

;Table of Contents: Background; Emissions from Chlorobenzenes Production; Emissions from Major Uses of Chlorobenzene; Emission from the Use of Materials Containing Chlorobenzenes; Byproduct Emission -- Processes Unrelated to Production or Use of Chlorobenzenes; Ambient Air and Stationary Source Test Procedures; Potential Source Categories of Chlorobenzenes Emissions; Textile Fiber Dyeing Facilities with Annual Sales Greater Than $1 Million; and Summary of Emission Factors Listed in this Document.

Not Available

1994-03-01

349

Volatile Organic Compounds (VOCs)  

MedlinePLUS

... ventilation during painting, and discarding paint supplies and special fuels that will not be used immediately. Keep exposure to perchloroethylene emissions from newly dry-cleaned materials to a minimum. ...

350

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

351

The use of conditional probability functions and potential source contribution functions to identify source regions and advection pathways of hydrocarbon emissions in Houston, Texas  

NASA Astrophysics Data System (ADS)

In this study, we demonstrate the utility of conditional probability functions (CPFs), potential source contribution functions (PSCFs), and hierarchical clustering analysis (HAC) to identify the source region and transport pathways of hydrocarbons measured at five photochemical assessment monitoring stations (PAMS) near the Houston Ship Channel from June to October 2003. In contrast to scatter plots, which only show the pair-wise correlation of species, commonality in CPF figures shows both correlation and information on the source region of the species in question. In this study, we use over 50 hourly volatile organic compound (VOC) concentrations and surface wind observations to show that VOCs with similar CPF patterns likely have common transport pathways. This was established with the multivariate technique, which uses the hierarchical clustering analysis to define clusters of VOCs having similar CPF patterns. This method revealed that alkenes, and in particular those with geometric isomers such as cis-/ trans-2-butene and cis-/ trans-2-pentene, have similar CPF patterns and hence, a common area of origin. The alkane isomers often show CPF patterns among themselves, and similarly, aromatic compounds often show similar patterns. We also show how calculated trajectory information can be used in the PSCF analysis to produce a graphic picture that identifies specific geographic areas associated with a given VOC (or other pollutant). The use of these techniques in the chemically and meteorologically complex environment of Houston, Texas, suggests its further utility in other areas with relatively simpler conditions.

Xie, Yulong; Berkowitz, Carl M.

352

The Use of Conditional Probability Functions and Potential Source Contribution Functions to Identify Source Regions and Advection Pathways of Hydrocarbon Emissions in Houston, Texas  

SciTech Connect

In this study, we demonstrate the utility of conditional probability functions (CPFs), potential source contribution functions (PSCFs), and hierarchical clustering analysis to identify the source region and transport pathways of hydrocarbons measured at five photochemical assessment monitoring stations (PAMS) near the Houston ship channel from June to October 2003. Over 50 volatile organic compound (VOC) concentrations were measured on the hourly collected samples. Routine surface observations of wind directions measured at each of the receptor sites were used extensively. We show that VOCs with similar CPF patterns likely have common transport pathways. This was established with the multivariate technique, which uses the hierarchical clustering analysis to allow clusters of groups of VOCs to form with similar CPF patterns. This method revealed that alkenes, and in particular those with geometric isomers such as cis-/trans-2-butene and cis-/trans-2-pentene, have similar CPF patterns. The alkane isomers often show CPF patterns among themselves, and similarly, aromatic compounds often show similar patterns among themselves too. We also show how trajectory information can be used in conjunction with the PSCF analysis to produce a graphic analysis suggesting specific source areas for a given VOC. The use of these techniques in the chemically and meteorologically complex environment of Houston, Texas, suggests its further utility in other areas with relatively simpler conditions.

Xie, YuLong; Berkowitz, Carl M.

2007-09-01

353

Outer heliospheric radio emissions. II - Foreshock source models  

NASA Technical Reports Server (NTRS)

Observations of LF radio emissions in the range 2-3 kHz by the Voyager spacecraft during the intervals 1983-1987 and 1989 to the present while at heliocentric distances greater than 11 AU are reported. New analyses of the wave data are presented, and the characteristics of the radiation are reviewed and discussed. Two classes of events are distinguished: transient events with varying starting frequencies that drift upward in frequency and a relatively continuous component that remains near 2 kHz. Evidence for multiple transient sources and for extension of the 2-kHz component above the 2.4-kHz interference signal is presented. The transient emissions are interpreted in terms of radiation generated at multiples of the plasma frequency when solar wind density enhancements enter one or more regions of a foreshock sunward of the inner heliospheric shock. Solar wind density enhancements by factors of 4-10 are observed. Propagation effects, the number of radiation sources, and the time variability, frequency drift, and varying starting frequencies of the transient events are discussed in terms of foreshock sources.

Cairns, Iver H.; Kurth, William S.; Gurnett, Donald A.

1992-01-01

354

Milagro Observations of TeV Emission from Galactic Sources in the Fermi Bright Source List  

E-print Network

We present the result of a search of Milagro sky map for spatial correlations with sources from a subset of the recent Fermi Bright Source List (BSL). The BSL consists of the 205 most significant sources detected above 100 MeV by the Fermi Large Area Telescope. We select sources based on their categorization in the BSL, taking all confirmed or possible Galactic sources in the field of view of Milagro. Of the 34 Fermi sources selected, 14 are observed by Milagro at a significance of 3 standard deviations or more. We conduct this search with a new analysis which employs newly-optimized gamma-hadron separation and utilizes the full 8-year Milagro dataset. Milagro is sensitive to gamma rays above 1 TeV and these results extend the observation of these sources far above the Fermi energy band. With the new analysis and additional data, TeV emission is definitively observed associated with the Fermi pulsar J2229.0+6114, in the the Boomerang Pulsar Wind Nebula (PWN). Furthermore, an extended region of TeV emission is...

Abdo, A A; Aune, T; Berley, D; Chen, C; Christopher, G E; DeYoung, T; Dingus, B L; Ellsworth, R W; González, M M; Goodman, J A; Hays, E; Hoffman, C M; Huentemeyer, P H; Kolterman, B E; Linnemann, J T; McEnery, J E; Morgan, T; Mincer, A I; Némethy, P; Pretz, J; Ryan, J M; Parkinson, P M Saz; Shoup, A; Sinnis, G; Smith, A J; Vasileiou, V; Walker, G P; Williams, D A; Yodh, G B

2009-01-01

355

SETTING PRIORITIES FOR CONTROL OF FUGITIVE PARTICULATE EMISSIONS FROM OPEN SOURCES  

EPA Science Inventory

The report describes setting priorities for controlling fugitive particulate emissions. Emission rate estimates of suspended particulates from open sources in the U.S. were obtained from emission factors and source extents in the literature. Major open sources, with their estimat...

356

EVALUATION AND PERFORMANCE ASSESSMENT OF INNOVATIVE LOW-VOC CONTACT ADHESIVES IN WOOD LAMINATING OPERATIONS  

EPA Science Inventory

The report gives results of an evaluation and assessment of the perfor-mance, economics, and emission reduction potential upon application of low-volatile organic compound (VOC) waterborne contact adhesive formulations specifically ina manual laminating operation for assembling s...

357

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 20 m(3) walk-in climate chamber at low (~5 ppb) and high ozone (~50 ppb) 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

358

Emissions of volatile organic compounds from hybrid poplar depend on CO2 concentration and genotype  

NASA Astrophysics Data System (ADS)

Hybrid poplar is a fast-growing tree species that is likely to be an important source of biomass for the production of cellulose-based biofuels and may influence regional atmospheric chemistry through the emission of volatile organic compounds (VOCs). We used proton-transfer reaction mass spectrometry to measure VOC emissions from the leaves of four different hybrid poplar genotypes grown under ambient (400 ppm) and elevated (650 ppm) carbon dioxide concentration (CO2). The purpose of this experiment was to determine whether VOC emissions are different among genotypes and whether these emissions are likely to change as atmospheric CO2 rises. Methanol and isoprene made up over 90% of the VOC emissions and were strongly dependent on leaf age, with young leaves producing primarily methanol and switching to isoprene production as they matured. Monoterpene emissions were small, but tended to be higher in young leaves. Plants grown under elevated CO2 emitted smaller quantities of both methanol and isoprene, but the magnitude of the effect was dependent on genotype. Isoprene emission rates from mature leaves dropped from ~35 to ~28 nmol m-2 s-1 when plants were grown under elevated CO2. Emissions from individuals grown under ambient CO2 varied more based on genotype than those grown under elevated CO2, which means that we might expect smaller differences between genotypes in the future. Genotype and CO2 also affected how much carbon (C) individuals allocated to the production of VOCs. The emission rate of C from VOCs was 0.5 - 2% of the rate at which C was assimilated via net photosynthesis. The % C emitted was strongly related to genotype; clones from crosses between Populus deltoides and P. trichocarpa (T x D) allocated a greater % of their C to VOC emissions than clones from crosses of P. deltoids and P. nigra (D x N). Individuals from all four genotypes allocated a smaller % of their C to the emission of VOCs when they were grown under elevated CO2. These results illustrate that even in closely related individuals there are inherent differences in VOC emissions that are not due to simple differences in metabolic rates and that elevated CO2 reduces these inherent differences. Even though VOC rates were lower under elevated CO2 they were still much higher than emissions reported for switchgrass, another biofuel species, which means that future regional air quality around biofuel plantations will be influenced by the choice of biofuel species.

Eller, A. S.; de Gouw, J. A.; Monson, R. K.

2010-12-01

359

[Characteristics of odors and VOCs from sludge direct drying process].  

PubMed

Co-processing sewage sludge by using the high-temperature feature of cement kiln can realize harmless disposal and energy recycling. In this paper, investigation on characteristics of the flue gas from sludge drying process was carried out in Guangzhou Heidelberg Yuexiu Cement Co., LTD. The composition and the main source of odors and volatile organic compounds (VOCs) emitted during the drying process were analyzed, aimed to provide scientific basis for the treatment of sewage sludge. Results showed that there were a large number of malodorous substances and VOCs in the flue gas. Sulfur dioxide and other sulfur-containing compounds were the main components in the malodorous substances, while benzene derivatives were predominant in VOCs. The compositions of odors and VOCs were influenced by the characteristics of the sludge and the heat medium (kiln tail gas). Total organic compounds in the sludge were significantly decreased after drying. Other organic substances such as volatile fatty acid, protein, and polysaccharide were also obviously reduced. The organic matter in sludge was the main source of VOCs in the flue gas. Part of sulfurous substances, such as sulfur dioxide, carbon disulfide, were from sulfur-containing substances in the sludge, and the rest were from the kiln tail gas itself. PMID:25338358

Chen, Wen-He; Deng, Ming-Jia; Luo, Hui; Zhang, Jing-Ying; Ding, Wen-Jie; Liu, Jun-Xin; Liu, Jun-Xin

2014-08-01

360

METHANOL MASER EMISSION FROM GALACTIC CENTER SOURCES WITH EXCESS 4.5 {mu}m EMISSION  

SciTech Connect

We present a study of signatures of on-going star formation in a sample of protostellar objects with enhanced 4.5 {mu}m emission ('green' sources) near the Galactic center. To understand how star formation in the Galactic center region compares to that of the Galactic disk, we used the Expanded Very Large Array to observe radiatively excited Class II 6.7 GHz CH{sub 3}OH masers and collisionally excited Class I 44 GHz CH{sub 3}OH masers, both tracers of high-mass star formation, toward a sample of 34 Galactic center and foreground 'green' sources. We find that 33% {+-} 15% of Galactic center sources are coincident with 6.7 GHz masers, and that 44% {+-} 17% of foreground sources are coincident with 6.7 GHz masers. For 44 GHz masers, we find correlation rates of 27% {+-} 13% and 25% {+-} 13% for Galactic center green sources and foreground green sources, respectively. Based on these CH{sub 3}OH maser detection rates, as well as correlations of green sources with other tracers of star formation, such as 24 {mu}m emission and infrared dark clouds (IRDCs), we find no significant difference between the green sources in the Galactic center and those foreground to it. This suggests that once the star formation process has begun, the environmental differences between the Galactic center region and the Galactic disk have little effect on its observational signatures. We do find, however, some evidence that may support a recent episode of star formation in the Galactic center region.

Chambers, E. T.; Yusef-Zadeh, F.; Roberts, D., E-mail: e-chambers@northwestern.edu, E-mail: zadeh@northwestern.edu, E-mail: doug-roberts@northwestern.edu [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)

2011-05-20

361

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

362

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--VOCS IN WATER ANALYTICAL RESULTS  

EPA Science Inventory

The VOCs in Water data set contains analytical results for measurements of up to 26 volatile organic compounds (VOCs) in 97 water samples over 61 households. Samples were collected at the tap and any additional drinking water source used extensively within each residence. The p...

363

40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?  

Code of Federal Regulations, 2011 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?...

2011-07-01

364

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

365

40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?  

...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?...

2014-07-01

366

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

367

40 CFR 63.5988 - What emission limitations must I meet for puncture sealant application affected sources?  

Code of Federal Regulations, 2012 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?...

2012-07-01

368

40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.  

Code of Federal Regulations, 2011 CFR

... Rule for the registration of air pollution sources and the reporting of emissions... Rule for the registration of air pollution sources and the reporting of emissions...current and accurate record of air pollution sources and their emissions...

2011-07-01

369

40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.  

Code of Federal Regulations, 2010 CFR

... Rule for the registration of air pollution sources and the reporting of emissions... Rule for the registration of air pollution sources and the reporting of emissions...current and accurate record of air pollution sources and their emissions...

2010-07-01

370

40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.  

Code of Federal Regulations, 2012 CFR

... Rule for the registration of air pollution sources and the reporting of emissions... Rule for the registration of air pollution sources and the reporting of emissions...current and accurate record of air pollution sources and their emissions...

2012-07-01

371

40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.  

Code of Federal Regulations, 2013 CFR

... Rule for the registration of air pollution sources and the reporting of emissions... Rule for the registration of air pollution sources and the reporting of emissions...current and accurate record of air pollution sources and their emissions...

2013-07-01

372

40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.  

... Rule for the registration of air pollution sources and the reporting of emissions... Rule for the registration of air pollution sources and the reporting of emissions...current and accurate record of air pollution sources and their emissions...

2014-07-01

373

40 CFR 63.1299 - Standards for slabstock flexible polyurethane foam production-source-wide emission limitation.  

Code of Federal Regulations, 2010 CFR

...flexible polyurethane foam production-source-wide emission limitation. 63.1299...STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards...flexible polyurethane foam production—source-wide emission limitation. Each...

2010-07-01

374

Alcohol, Volatile Fatty Acid, Phenol, and Methane Emissions from Dairy Cows and Fresh Manure  

Microsoft Academic Search

Th ere are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their manure as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOCs) and greenhouse gases (GHGs). We report measurements of alcohols, volatile fatty acids, phenols, and methane (CH 4) emitted from

Huawei Sun; Steven L. Trabue; Kenwood Scoggin; Wendi A. Jackson; Yuee Pan; Yongjing Zhao; Irina L. Malkina; Jacek A. Koziel; Frank M. Mitloehner

2008-01-01

375

Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure  

Technology Transfer Automated Retrieval System (TEKTRAN)

There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their waste as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOC) and greenhouse gases (GH...

376

MODULATING EMISSIONS FROM ELECTRIC GENERATING UNITS AS A FUNCTION OF METEOROLOGICAL VARIABLES  

EPA Science Inventory

Electric Generating Units (EGUs) are an important source of emissions of nitrogen oxides (NOx), which react with volatile organic compounds (VOCs) in the presence of sunlight to form ozone. Emissions from EGUs are believed to vary depending on short-term demands for electricity;...

377

Global methane emissions from minor anthropogenic sources and biofuel combustion in residential stoves  

Microsoft Academic Search

Most global methane (CH4) budgets have failed to include emissions from a diverse group of minor anthropogenic sources. Individually, these minor sources emit small quantities of CH4, but collectively, their contributions to the budget may be significant. In this paper, CH4 emissions are estimated for a wide variety of individual minor emissions sources on a country-specific basis. Emissions from biomass

Stephen D. Piccot; Lee Beck; Sridhar Srinivasan; Sharon L. Kersteter

1996-01-01

378

Global methane emissions from minor anthropogenic sources and biofuel combustion in residential stoves  

Microsoft Academic Search

Most global methane (CH4) budgets have failed to include emissions from a diverse group of minor anttu'opogenic sources. Individually, these minor sources emit small quantities of CH4, but collectively, their contributions to the budget may be significant. In this paper, CH 4 emissions are estimated for a wide variety of individual minor emissions sources on a country-specific basis. Emissions from

Stephen D. Piccot; Lee Beck; Sridhar Srinivasan; Sharon L. Kersteter

1996-01-01

379

Overview of the ECHO Project: Emissions and Chemical Transformation of Biogenic Volatile Organic Compounds - Investigations in and above a mixed forest stand  

NASA Astrophysics Data System (ADS)

Forests are complex sources of biogenic volatile organic compounds (VOC) in the planetary boundary layer. With estimated emission rates of 1150 TgC/year, biogenic emissions dominate over those from anthropogenic sources by one order of magnitude on a global scale. Due to their emission in large quantities and their high reactivity biogenic VOCs have a significant impact on the photochemical processes that lead to the formation of ozone and other photooxidants in the planetary boundary layer (PBL). A considerable lack of knowledge exists concerning a typical forest stand as a net source of reactive trace compounds, the amount of primary emitted VOC which are transported directly into the PBL, and the amount of VOC which are chemically processed within the canopy, the products of which are transported into the PBL. ECHO is an integrated project which investigates the role of forests as source and chemical reactor of reactive trace gases. It comprises of a combination of large field campaigns, simulation experiments, and laboratory studies to investigate net VOC emissions from plants, chemical reactions of the emitted VOCs in the atmosphere, and transport processes in and above a forest stand. Here we describe the aims and concept of ECHO and present first results of the 2002 Intense phase of the field campaign.

Komenda, M.; Echo Team

2003-04-01

380

Source characteristics of volatile organic compounds during high ozone episodes in Hong Kong, Southern China  

NASA Astrophysics Data System (ADS)

Measurements of Volatile Organic Compounds (VOC) are analyzed to characterize the sources impacting the Hong Kong area. The ratios of different VOC species, m,p-xylenes-to-ethylbenzene, C6H14-to-toluene and p-xylene-to-total xylenes are used for diagnostic analyses. Photochemical age analysis shows that the sources of reactive aromatics, the most important contributor to the photochemical reactivity, do not appear to be preferentially located in downtown Hong Kong. In addition, they do not appear to be dominated by mobile emissions based on the analyses of speciated VOC data from an earlier study, but related to industrial, waterfront, and fuel-storage activities. The ratios, p-xylene-to-total xylenes and dSO2/dNOy, suggest that the anomalously high pollutant concentrations in western Hong Kong in the early morning hours of two episode days appear to have come from transport of urban-type emissions. Comparison of observed ambient ratios of selected VOC and their ratios in the speciated VOC emission inventories for Hong Kong and adjacent Pearl River Delta (PRD) Region give mixed results. The observed ratio C6H14-to-toluene is consistent with the speciated version of the VOC emission inventory. The ratios of selected alkanes are not. This may be caused by the inaccuracies in the inventory and/or the speciation method.

Zhang, J.; Wang, T.; Chameides, W. L.; Cardelino, C.; Blake, D. R.; Streets, D. G.

2008-05-01

381

Source characteristics of volatile organic compounds during high ozone episodes in Hong Kong, Southern China  

NASA Astrophysics Data System (ADS)

Measurements of Volatile Organic Compounds (VOC) are analyzed to characterize the sources impacting the Hong Kong area. The ratios of different VOC species, m,p-xylenes-to-ethylbenzene, C6H14-to-toluene and p-xylene-to-total xylenes are used for diagnostic analyses. Photochemical age analysis shows that the sources of reactive aromatics, the most important contributor to the photochemical reactivity, do not appear to be preferentially located in downtown Hong Kong. In addition, they do not appear to be dominated by mobile emissions based on the analyses of speciated VOC data from an earlier study, but related to industrial, waterfront, and fuel-storage activities. The ratios, p-xylene-to-total xylenes and dSO2/dNOy, suggest that the anomalously high pollutant concentrations in western Hong Kong in the early morning hours of two episode days appear to have come from transport of urban-type emissions. Comparison of observed ambient ratios of selected VOC and their ratios in the speciated VOC emission inventories for Hong Kong and adjacent Pearl River Delta (PRD) Region gives mixed results. The observed ratio C6H14-to-toluene is consistent with the speciated version of the VOC emission inventory. The ratios of selected alkanes are not. This may be caused by the inaccuracies in the inventory and/or the speciation method.

Zhang, J.; Wang, T.; Chameides, W. L.; Cardelino, C.; Blake, D. R.; Streets, D. G.

2008-08-01

382

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

383

GROUND WATER SAMPLING FOR VOCS  

EPA Science Inventory

Sampling protocol should be dictated by the sampling objective(s). It is important to obtain representative ground water samples, regardless of the sampling objective(s). Low-flow (minimum draw-down) purging and sampling techniques are best in most instances, particularly for VOC...

384

Trace gas emissions through a winter snowpack in the subalpine ecosystem at Niwot Ridge, Colorado  

NASA Astrophysics Data System (ADS)

A preliminary study of whole air measurements within a snowpack in the subalpine forest of Colorado found that lower snow layers and underlying soil were a strong source of chemically active trace gases (VOC). The emissions of trace gases were correlated with emissions of radiatively active greenhouse gases (CO2 and N2O) through the snowpack. Carbon dioxide was enhanced in the lower snowpack to over 1000 ppmv, similar to previous studies, which have shown that a thermal insulation of snow covering the soil leads to enhanced emissions of CO2 equivalent to a large fraction of annual respiration. Comparable enhancements of several VOCs reached 1275, 1670, and 1000 pptv for methyl chloride, propane, and ?-pinene, respectively. The measurements are limited to a one-day pilot study, however, considering that previous studies have reported significant CO2 emissions through snowpacks any emissions of VOC may also be important on a local or potentially global scale.

Swanson, Aaron L.; Lefer, Barry L.; Stroud, Verity; Atlas, Elliot

2005-02-01

385

Z mode waves as the source of Saturn narrowband radio emissions  

E-print Network

Z mode waves as the source of Saturn narrowband radio emissions ShengYi Ye,1 J. D. Menietti,1 G present the first magnetic field measurements of Saturn narrowband emissions validating. S. Kurth (2010), Z mode waves as the source of Saturn narrowband radio emissions, J. Geophys. Res

Gurnett, Donald A.

386

X-RAY EMISSION FROM THE SOMBRERO GALAXY: DISCRETE SOURCES  

SciTech Connect

We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of {approx}200 ks. With a detection limit of L{sub X} {approx} 10{sup 37} erg s{sup -1} and a field of view covering a galactocentric radius of {approx}30 kpc (11.'5), 383 sources are detected. Cross-correlation with Spitler et al.'s catalog of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-ray sources in GCs, presumably low-mass X-ray binaries (LMXBs). Metal-rich GCs are found to have a higher probability of hosting these LMXBs, a trend similar to that found in elliptical galaxies. On the other hand, the four most luminous GC LMXBs, with apparently super-Eddington luminosities for an accreting neutron star, are found in metal-poor GCs. We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-law indices ({approx}1.1 for the GC-LF and {approx}1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC-LF at fainter luminosities down to 10{sup 35} erg s{sup -1}. The derived index rules out a faint-end slope flatter than 1.1 at a 2{sigma} significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of {approx}1.0 below 10{sup 37} erg s{sup -1}. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic active galactic nuclei (52 {+-} 11 [1{sigma}]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.

Li Zhiyuan; Jones, Christine; Forman, William R.; Kraft, Ralph P.; Stefano, Rosanne Di [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Spitler, Lee R. [Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122 (Australia); Tang, Shikui; Wang, Q. Daniel [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Gilfanov, Marat [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str 1, 85741 Garching bei Muenchen (Germany); Revnivtsev, Mikhail, E-mail: zyli@cfa.harvard.ed [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstr. 2, 85748 Garching (Germany)

2010-10-01

387

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

NASA Astrophysics Data System (ADS)

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 tall flux tower installation a few kilometers north of downtown Houston. We measure energy and trace gas fluxes, including VOCs from both anthropogenic and biogenic emission sources in the urban surface layer using eddy covariance and related techniques. Here, we describe a Relaxed Eddy Accumulation (REA) system combined with a dual-channel GC-FID used for VOC flux measurements, including first results. Ambient air is sampled at approximately 15 L min-1 through a 9.5 mm OD PFA line from 60 m above ground next to a sonic anemometer. Subsamples of this air stream are extracted through an ozone scrubber and pushed into two Teflon bag reservoirs, from which they are transferred to the GC pre-concentration units consisting of carbon-based adsorption traps encapsulated in heater blocks for thermal desorption. We discuss the performance of our system and selected measurement results from the 2008 spring and summer seasons in Houston. We present diurnal variations of the fluxes of the traffic tracers benzene, toluene, ethylbenzene, and xylenes (BTEX) during different study periods. Typical BTEX fluxes ranged from -0.36 to 3.10 mg m-2 h-1 for benzene, and -0.47 to 5.04 mg m-2 h-1 for toluene, and exhibited diurnal cycles with two dominant peaks related to rush-hour traffic. A footprint analysis overlaid onto a geographic information system (GIS) will be presented to reveal the dominant emission sources and patterns in the study area.

Park, C.; Schade, G.; Boedeker, I.

2008-12-01

388

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...

389

SOA formation potential of emissions from soil and leaf litter.  

PubMed

Soil and leaf litter are significant global sources of small oxidized volatile organic compounds, VOCs (e.g., methanol and acetaldehyde). They may also be significant sources of larger VOCs that could act as precursors to secondary organic aerosol (SOA) formation. To investigate this, soil and leaf litter samples were collected from the University of Idaho Experimental Forest and transported to the laboratory. There, the VOC emissions were characterized and used to drive SOA formation via dark, ozone-initiated reactions. Monoterpenes dominated the emission profile with emission rates as high as 228 ?g-C m(-2) h(-1). The composition of the SOA produced was similar to biogenic SOA formed from oxidation of ponderosa pine emissions and ?-pinene. Measured soil and litter monoterpene emission rates were compared with modeled canopy emissions. Results suggest surface soil and litter monoterpene emissions could range from 12 to 136% of canopy emissions in spring and fall. Thus, emissions from leaf litter may potentially extend the biogenic emissions season, contributing to significant organic aerosol formation in the spring and fall when reduced solar radiation and temperatures reduce emissions from living vegetation. PMID:24328143

Faiola, Celia L; Vanderschelden, Graham S; Wen, Miao; Elloy, Farah C; Cobos, Douglas R; Watts, Richard J; Jobson, B Thomas; Vanreken, Timothy M

2014-01-21

390

Low VOC drying of lumber and wood panel products. Progress report No. 4, annual summary  

SciTech Connect

Heating softwood in a low-headspace environment draws out the VOCs from the wood, without removing the water. The VOCs can be collected from the headspace, and represent a valuable product. The VOC-depleted wood can then be dried conventionally with much reduced emissions. Heating can be accomplished through radiofrequency (RF) or steam. For lumber, steam is inefficient, but brief RF treatment under low-headspace conditions draws out 80% of the VOCs. The power used is quite low, since the RF energy is not used to remove water, but only to maintain the wood at a set temperature. The technology is now at the pre-pilot stage. Either steam or RF can be used for particle, OSB, and veneer, again under low-headspace conditions. Increasing steam temperature facilitates VOC removal. In order to understand the mechanism of VOC release in lumber, the transport of water and VOCs to the surface is being studied as a function of sample size and orientation. Characterization of the terpenes and resin/fatty acids from a control set of trees is underway in order to define the seasonal influence on VOCs.

Boerner, J.; Su, Wei; Yan, Hui [and others] [and others

1997-07-01

391

NMVOCs speciated emissions from mobile sources and their effect on air quality and human health in the metropolitan area of Buenos Aires, Argentina  

NASA Astrophysics Data System (ADS)

Since 2007, more than half of the world's population live in urban areas. Urban atmospheres are dominated by pollutants associated with vehicular emissions. Transport emissions are an important source of non-methane volatile organic compounds (NMVOCs) emissions, species of high interest because of their negative health effects and their contribution to the formation of secondary pollutants responsible for photochemical smog. NMVOCs emissions are generally not very well represented in emission inventories and their speciation presents a high level of uncertainty. In general, emissions from South American countries are still quite unknown for the international community, and usually present a high degree of uncertainty due to the lack of available data to compile emission inventories. Within the Inter-American Institute for Global Change Research (IAI, www.iai.int) projects, UMESAM (Urban Mobile Emissions in South American Megacities) and SAEMC (South American Emissions, Megacities and Climate, http://saemc.cmm.uchile.cl/), the effort was made to compute on-road transport emission inventories for South American megacities, namely Bogota, Buenos Aires, Lima, Sao Paulo and Santiago de Chile, considering megacities as urban agglomerations with more than 5 million inhabitants. The present work is a continuation of these projects, with the aim to extend the calculated NMVOCs emissions inventory into the individual species required by CTMs. The on-road mobile sector of the metropolitan area of Buenos Aires (MABA), Argentina, accounted for 70 Gg of NMVOCs emissions for 2006, without considering two-wheelers. Gasoline light-duty vehicles were responsible for 64% of NMVOCs emissions, followed by compressed natural gas (CNG) light-duty vehicles (22%), diesel heavy-duty vehicles (11%) and diesel light-duty vehicles (7%). NMVOCs emissions were speciated according to fuel and technology, employing the European COPERT (Ntziachristos & Samaras, 2000) VOCs speciation scheme for gasoline and diesel vehicles and the USEPA SPECIATE (Simon et al., 2010) profile for CNG vehicles. NMVOCs emissions were composed of 31% aromatic compounds, 29% linear alkanes, 20% olefins, 12% ramified alkanes, 7% aldehydes and negligible contributions from cycloalkanes, ketones, Polycyclic Aromatic Hydrocarbons (PAHs) and other NMVOCs. Aromatic compounds dominated gasoline light-duty vehicles' emissions (~45%), while linear alkanes those of CNG light-duty vehicles (~80%). Aldehydes' contributions increased for diesel light and heavy-duty vehicles. VOCs speciation schemes for transport emissions were collected from the literature from Europe, USA, Asia, Oceania and Latin America with the aim to account for the associated uncertainty by compound for each fuel and technology type. The resulting individual NMVOCs emissions were used to calculate the corresponding tropospheric ozone formation (Carter, 1994), as well as the human toxicity potential in terms of 1.4 dichlorobenzene. Olefins and aromatic compounds in terms of species, and gasoline in terms of fuels, were found to impose the highest risk in urban environments regarding air quality and human health.

D'Angiola, Ariela; Dawidowski, Laura; Gomez, Dario; Granier, Claire

2014-05-01

392

Top-Down Constraints on the Emissions of Anthropogenic Volatile Organic Compounds from a Mega-City  

NASA Astrophysics Data System (ADS)

During the CalNex study in May-June of 2010, an extensive set of volatile organic compounds (VOCs) was measured in the Los Angeles basin and its in- and outflow areas. Measurements were made from the NOAA WP-3D research aircraft, the research vessel Atlantis and a ground site in Pasadena, California. In this presentation, the results are used to derive top-down constraints on the emissions of anthropogenic VOCs from this North-American megacity. The VOC data from CalNex in 2010 are put in perspective by comparing them with results from an earlier flight of the NOAA WP-3D in the Los Angeles basin in 2002, from a number of other earlier studies and from two different air quality monitoring networks. Strongly decreasing trends of ~7% per year are observed for most VOCs that are emitted from motor vehicles or photo-chemically produced from these emissions. Decreasing trends are less strong for small alkanes, which are mostly from natural gas related emissions, and oxygenated VOCs produced from them. The composition of urban VOC emissions was determined using the data obtained by gas-chromatography mass spectrometry at the ground site in Pasadena. Emission ratios of hydrocarbons versus ethyne were obtained using two methods. First, emission ratios were determined from nighttime data only. Second, the degree of photochemical processing of the sampled air masses was estimated, and emission ratios were determined by extrapolating to a zero photochemical age. Both methods agreed within the combined uncertainties for most VOCs. The composition of urban VOC emissions in Los Angeles was compared with other urban regions including in the U.S. and Europe and found to be similar. Measurements of ethanol at the ground site in Pasadena showed much higher mixing ratios than observed earlier in the northeastern U.S. The difference is attributed in part to the strongly increased use of fuel ethanol in the U.S.: in 2010, about 10% of gasoline consisted of ethanol, whereas that percentage was about 1% in the early 2000s. The relative importance of emissions and photochemical formation of oxygenated VOCs is also studied using data from the ground site in Pasadena. It is found that aldehydes, ketones and glyoxal have significant direct emissions in addition to secondary formation sources. The direct emissions are not well represented in emission inventories. Acids have no or small direct emissions but significant secondary formation that is difficult to account for using our best understanding of the gas-phase chemistry. Alcohols have direct emission sources but no or small secondary formation.

De Gouw, J. A.; Warneke, C.; Borbon, A.; Gilman, J. B.; Kuster, W. C.; Parrish, D. D.; Atlas, E. L.; Blake, D. R.

2012-12-01

393

Measurement and Correlation of Ambient VOCs in Windsor, Ontario, Canada and Detroit, Michigan, USA  

NASA Astrophysics Data System (ADS)

An air quality study has been carried out in Windsor, Ontario, Canada and Detroit, Michigan, USA as part of a pilot research study undertaken by the Geospatial Determinants of Health Outcomes Consortium (GeoDHOC), a multidisciplinary, international effort aimed at understanding the health effects of air pollution in urban environments. Exposure to volatile organic compounds has long been associated with adverse health conditions such as atrophy of skeletal muscles, loss of coordination, neurological damage, dizziness, throat, nose, and eye irritation, nervous system depression, liver damage, and respiratory symptoms. Twenty-six species of ambient volatile organic compounds (VOCs) were monitored during a 2-week period in September, 2008 at 100 sites across Windsor and Detroit, using 3M # 3500 Organic Vapour Monitors. Ten species with highest concentrations were selected for further investigation; Toluene (mean concentration =4.14 ?m/m3), (m+p)-Xylene (2.30 ?m/m3), Hexane (1.87 ?m/m3), Benzene (1.37 ?m/m3), 1,2,4-Trimethylbenzene (0.87 ?m/m3), Dichloromethane (0.77 ?m/m3), Ethylbenzene (0.68 ?m/m3), o-Xylene (0.63 ?m/m3), n-Decane (0.42 ?m/m3), and 1,3,5-Trimethylbenzene (0.39 ?m/m3). Comparison to a similar investigation in Sarnia, Ontario in October 2005 revealed that the mean concentrations of VOCs were higher in Windsor-Detroit for all species by a significant margin (31-958%), indicating substantial impact of local industrial and vehicular emissions in the WindsorVDetroit area. For most VOCs, the concentrations were higher in Detroit than in Windsor. The mean concentration of total VOC was 9.7 ?m/m3 in Windsor, which is slightly higher than that in Sarnia in 2005 (7.9 um/m3), whilst total VOC concentration in Detroit was much higher (16.5 ?m/m3). There were strong correlations among several of the 10 species, with the highest Pearson correlation coefficients (r=0.78 - 0.99, p<0.05) amongst the BTEX (benzene, toluene, ethylbenzene, and xylenes) group, suggesting common sources of these species. The BTEX correlation for this study was in good agreement with that from the Sarnia results (Spearman rank correlation coefficient r=0.75 - 0.99), suggesting that one species may act as a proxy for the others in geographically similar regions.

Miller, L. J.; You, H.; Xu, X.; Molaroni, S.; Lemke, L.; Weglicki, L.; Krouse, H.; Krajenta, R.

2009-05-01

394

CONTROL OF HYDROCARBON EMISSIONS FROM GASOLINE LOADING BY REFRIGERATION SYSTEMS  

EPA Science Inventory

The report gives results of a study of the capabilities of refrigeration systems, operated at three temperatures, to control volatile organic compound (VOC) emissions from truck loading at bulk gasoline terminals. Achievable VOC emission rates were calculated for refrigeration sy...

395

Impact of carbon source on nitrous oxide emission from anoxic/oxic biological nitrogen removal process and identification of its emission sources.  

PubMed

Wastewater treatment is an important source of nitrous oxide (N(2)O), which is a strong greenhouse gas and dominate ozone-depleting substance. The purpose of this study was to evaluate the effect of carbon source on N(2)O emission from anoxic/oxic biological nitrogen removal process. The mechanisms of N(2)O emission were also studied. Long-term experiments were operated to evaluate the effect of three different carbon sources (i.e., glucose, sodium acetate, and soluble starch) on N(2)O emission characteristics. And batch experiments, in the presence or absence of specific inhibitors, were carried out to identify the sources of N(2)O emission. The ammonia-oxidizing bacteria (AOB) and denitrifiers community compositions under different circumstances were also analyzed based on which the underlying mechanisms of N(2)O emission were elucidated. The conversion ratios of N(2)O in reactors with glucose, sodium acetate, and soluble starch were 5.3 %, 8.8 %, and 2.8 %, respectively. The primary process responsible for N(2)O emission was nitrifier denitrification by Nitrosomonas-like AOB, while denitrification by heterotrophic denitrifiers acted as the sink. Reactor with sodium acetate showed the highest N(2)O emission, together with the highest nitrogen and phosphate removal ratios. Carbon source has a significant impact on N(2)O emission quantity and relatively minor effect on its production mechanism. PMID:22684879

Hu, Zhen; Zhang, Jian; Li, Shanping; Xie, Huijun

2013-02-01

396

Characteristics of volatile organic compounds (VOCs) emitted from a petroleum refinery in Beijing, China  

NASA Astrophysics Data System (ADS)

This study made a field VOCs (volatile organic compounds) measurement for a petroleum refinery in Beijing by determining 56 PAMS VOCs, which are demanded for photochemical assessment in US, and obtained the characteristics of VOCs emitted from the whole refinery and from its inner main devices. During the monitoring period, this refinery brought about an average increase of 61 ppbv in the ambient TVOCs (sum of the PAMS VOCs) at the refinery surrounding area, while the background of TVOCs there was only 10-30 ppbv. In chemical profile, the VOCs emitted from the whole refinery was characteristic by isobutane (8.7%), n-butane (7.9%), isopentane (6.3%), n-pentane (4.9%%), n-hexane (7.6%), C6 branched alkanes (6.0%), propene (12.7%), 1-butene (4.1%), benzene (7.8%), and toluene (5.9%). On the other hand, the measurement for the inner 5 devices, catalytic cracking units (CCU2 and CCU3), catalytic reforming unit (CRU), tank farm (TF), and wastewater treatment(WT), revealed the higher level of VOCs pollutions (about several hundred ppbv of TVOCs), and the individual differences in VOCs chemical profiles. Based on the measured speciated VOCs data at the surrounding downwind area, PMF receptor model was applied to identify the VOCs sources in the refinery. Then, coupling with the VOCs chemical profiles measured at the device areas, we concluded that CCU1/3 contributes to 25.9% of the TVOCs at the surrounding downwind area by volume, followed by CCU2 (24.7%), CRU (18.9%), TF (18.3%) and WT (12.0%), which was accordant with the research of US EPA (2008). Finally, ozone formation potentials of the 5 devices were also calculated by MIR technique, which showed that catalytic cracking units, accounting for about 55.6% to photochemical ozone formation, should be given the consideration of VOCs control firstly.

Wei, Wei; Cheng, Shuiyuan; Li, Guohao; Wang, Gang; Wang, Haiyan

2014-06-01

397

40 CFR 63.1345 - Emissions limits for affected sources other than kilns; clinker coolers; new and reconstructed...  

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Emission Standards and Operating Limits § 63.1345 Emissions limits for affected sources...

2014-07-01

398

40 CFR 63.1345 - Emissions limits for affected sources other than kilns; clinker coolers; new and reconstructed...  

Code of Federal Regulations, 2013 CFR

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Emission Standards and Operating Limits § 63.1345 Emissions limits for affected sources...

2013-07-01

399

Solution for acoustic field of thermo-acoustic emission from arbitrary source  

NASA Astrophysics Data System (ADS)

In this work, an expression for acoustic field of thermo-acoustic (TA) emission from arbitrary source is presented by deriving the solutions of TA emission from spherical surface and point source in gas and then taking advantage of the point sources superposition and the surface heat distribution factor. Accordingly, the computational analysis of acoustic pressure field of TA emission is extended to three-dimensional cases. The theory developed in this work is in good agreement with the experimental results and applicable for solving many complex and important TA emission problems including nanothermophones and phased array and impulse-driven TA emissions.

Hu, Hanping; Wang, Dongdong; Wang, Zedong

2014-10-01

400

Tracking the sources of tropospheric ozone  

NASA Astrophysics Data System (ADS)

Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this set of studies we examine the attribution of tropospheric ozone to emissions of VOC using a tagging approach, whereby each VOC oxidation intermediate in model chemical mechanisms is tagged with the identity of its primary emitted compound, allowing modelled ozone production to be directly attributed to all emitted VOCs in the model. Using a global model we examine the spatial and temporal extent of NOx-limited and VOC-limited regions with respect to ozone production chemistry, and we explore the sensitivity of the attributed ozone production to choices made during the tagging of the chemical mechanism. Using a regional model, we explore the extent to which transported VOC oxidation intermediates can be responsible for ozone production downwind of the original emissions source. Using a box model, we perform a detailed comparison of chemical mechanisms, examining the degree to which the explicitness of the representation of VOC oxidation intermediates influences the ozone production potential of VOC under idealised conditions. We also investigate uncertainties in the speciation of VOC emissions, as represented in state of the art emission inventories, and examine the extent to which these uncertainties can influence modelled ozone production. The representation of the emission of biogenic VOCs (BVOC) in our models is also improved. In particular, we implement a relationship between ozone stress and increased BVOC emissions. This is expected to be particularly important for urban trees. Based on the results of these studies, we recommend emission control measures based on their effectiveness in mitigating ozone air quality and climate forcing.

Butler, T. M.; Churkina, G.; Coates, J.; Grote, R.; Mar, K.; von Schneidemesser, E.; Zhu, S.

2013-12-01

401

Experimental biomass burning emission assessment by combustion chamber  

NASA Astrophysics Data System (ADS)

Biomass burning is a significant source of several atmospheric gases and particles and it represents an important ecological factor in the Mediterranean ecosystem. In this work we describe the performances of a recently developed combustion chamber to show the potential of this facility in estimating the emission from wildland fire showing a case study with leaves, small branches and litter of two representative species of Mediterranean vegetation, Quercus pubescens and Pinus halepensis. The combustion chamber is equipped with a thermocouple, a high resolution balance, an epiradiometer, two different sampling lines to collect organic volatile compounds (VOCs) and particles, a sampling line connected to a Proton Transfer Reaction Mass-Spectrometer (PTR-MS) and a portable analyzer to measure CO and CO2 emission. VOCs emission were both analyzed with GC-MS and monitored on-line with PTR-MS. The preliminary qualitative analysis of emission showed that CO and CO2 are the main gaseous species emitted during the smoldering and flaming phase, respectively. Many aromatics VOCs as benzene and toluene, and many oxygenated VOC as acetaldehyde and methanol were also released. This combustion chamber represents an important tool to determine the emission factor of each plant species within an ecosystem, but also the contribution to the emissions of the different plant tissues and the kinetics of different compound emissions during the various combustion phases. Another important feature of the chamber is the monitoring of the carbon balance during the biomass combustion.

Lusini, Ilaria; Pallozzi, Emanuele; Corona, Piermaria; Ciccioli, Paolo; Calfapietra, Carlo

2014-05-01

402

Emission and Chemical Transformation of Biogenic Volatile Organic Compounds (echo)  

NASA Astrophysics Data System (ADS)

Forests are complex sources of biogenic volatile organic compounds (VOC) in the planetary boundary layer. The impact of biogenic VOC on tropospheric photochem- istry, air quality, and the formation of secondary products affects our climate on a regional and global scale but is far from being understood. A considerable lack of knowledge exists concerning a forest stand as a net source of reactive trace com- pounds, which are transported directly into the planetary boundary layer (PBL). In particular, little is known about the amounts of VOC which are processed within the canopy. The goal of ECHO, which is presented in this poster, is to investigate these questions and to improve our understanding of biosphere-atmosphere interactions and their effects on the PBL. The investigation of emissions, chemical processing and vertical transport of biogenic VOC will be carried out in and above a mixed forest stand in Jülich, Germany. A large set of trace gases, free radicals and meteorologi- cal parameters will be measured at different heights in and above the canopy, covering concentrations of VOC, CO, O3, organic nitrates und NOx as well as organic aerosols. For the first time concentration profiles of OH, HO2, RO2 und NO3 radicals will be measured as well together with the actinic UV radiation field and photolysis frequen- cies of all relevant radical precursors (O3, NO2, peroxides, oxygenated VOC). The different tasks of the field experiments will be supported by simulation experiments investigating the primary emission and the uptake of VOC by the plants in stirred tank reactors, soil parameters and soil emissions in lysimeter experiments, and the chem- ical processing of the trace gases as observed in and above the forest stand in the atmosphere simulation chamber SAPHIR. The planning and interpretation of the field experiments is supported by simulations of th