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1

Characterizing reduced sulfur compounds and non-methane volatile organic compounds emissions from a swine concentrated animal feeding operation  

Microsoft Academic Search

Reduced sulfur compounds (RSCs) and non-methane volatile organic compounds (NMVOCs) emissions from concentrated animal feeding operations (CAFOs) have become a potential environmental and human health concern. Both RSCs and NMVOCs contribute to odor. In addition, RSCs also have the potential to form fine particulate matter (PMfine) and NMVOCs the potential to form ozone. Measurements of RSCs and NMVOCs emissions were

Ian Cooper Rumsey

2010-01-01

2

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

3

Chemical speciation and source apportionment of Non-Methane Volatile Organic Compounds (NMVOCs) in a Middle Eastern country  

NASA Astrophysics Data System (ADS)

NMVOCs, emitted from various sources, are of particular interest since they contribute to the formation of tropospheric ozone, PAN and secondary organic aerosols resulting in negative impacts on human health, climate and on the environment. To identify abatement measures, a profound knowledge of emission sources and their composition is a prerequisite. Air pollution in the Middle East region remains difficult to assess and understand because of a lack of ground-based measurements and the limited information on NMVOC chemical speciation and source apportionment. Based on a large database of NMVOC observations obtained in Beirut, the capital of Lebanon (a developing country in the Middle East region, located in Western Asia on the eastern shore of the Mediterranean Sea), the overall objective of this work is to apportion the sources of NMVOCs encountered in Lebanon. First, source profiles were determined with field measurements close to the main potential emitters namely the road transport, gasoline vapour, power generation and solvent uses. The results obtained are compared to other studies held in other regions and are used to assess the emission inventory developed for Lebanon. Secondly, two intensive field campaigns were held in a receptor site in Beirut during summer 2011 and winter 2012 in order to obtain a large time resolved dataset. The PMF analysis of this dataset was applied to apportion anthropogenic sources in this area. In both seasons, combustion (road transport and power generation) and gasoline evaporation, especially in winter, were the main sources contributing to the NMVOCs in Beirut. The results will support model implementation especially by completing the emission inventory established for the year 2010 by Waked et al. 2012 according to the EEA/EMEP guidelines because of the lack of Lebanon-specific emission factor.

Salameh, Therese; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

2014-05-01

4

Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions  

NASA Astrophysics Data System (ADS)

Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions decreases global annual average tropospheric methane and ozone by 36.6 ppbv and 3.3 Tg, respectively, and surface ozone by 0.67 ppbv. All regional reductions slow the production of peroxyacetyl nitrate (PAN), resulting in regional to intercontinental PAN decreases and regional NOx increases. These NOx increases drive tropospheric ozone increases nearby or downwind of source regions in the Southern Hemisphere (South America, Southeast Asia, Africa, and Australia). Some regions' NMVOC emissions contribute importantly to air pollution in other regions, such as East Asia, the Middle East, and Europe, whose impact on US surface ozone is 43%, 34%, and 34% of North America's impact. Global and regional NMVOC reductions produce widespread negative net RFs (cooling) across both hemispheres from tropospheric ozone and methane decreases, and regional warming and cooling from changes in tropospheric ozone and sulfate (via several oxidation pathways). The 100 yr and 20 yr global warming potentials (GWP100, GWP20) are 2.36 and 5.83 for the global reduction, and 0.079 to 6.05 and -1.13 to 18.9 among the 10 regions. The NMVOC RF and GWP estimates are generally lower than previously modeled estimates, due to the greater NMVOC/NOx emissions ratios simulated, which result in less sensitivity to NMVOC emissions changes and smaller global O3 burden responses, in addition to differences in the representation of NMVOCs and oxidation chemistry among models. Accounting for a fuller set of RF contributions may change the relative magnitude of each region's impacts. The large variability in the RF and GWP of NMVOCs among regions suggest that regionally specific metrics may be necessary to include NMVOCs in multi-gas climate trading schemes.

Fry, M. M.; Schwarzkopf, M. D.; Adelman, Z.; West, J. J.

2014-01-01

5

Characterizing reduced sulfur compounds and non-methane volatile organic compounds emissions from a swine concentrated animal feeding operation  

NASA Astrophysics Data System (ADS)

Reduced sulfur compounds (RSCs) and non-methane volatile organic compounds (NMVOCs) emissions from concentrated animal feeding operations (CAFOs) have become a potential environmental and human health concern. Both RSCs and NMVOCs contribute to odor. In addition, RSCs also have the potential to form fine particulate matter (PMfine) and NMVOCs the potential to form ozone. Measurements of RSCs and NMVOCs emissions were made from both an anaerobic lagoon and barn at a swine CAFO in North Carolina. Emission measurements were made over all four seasonal periods. In each seasonal period, measurements were made from both the anaerobic lagoon and barn for ˜1 week. RSC and NMVOCs samples were collected using passivated canisters. Nine to eleven canister samples were taken from both the lagoon and barn over each sampling period. The canisters were analyzed ex-situ using gas chromatography flame ionization detection (GC-FID). Hydrogen sulfide (H2S) measurements were made in-situ using a pulsed fluorescence H2S/SO2 analyzer. During sampling, measurements of meteorological and physiochemical parameters were made. H2S had the largest RSC flux, with an overall average lagoon flux of 1.33 mug m-2 min-1. The two main RSCs identified by the GC-FID, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), had overall average lagoon fluxes an order of magnitude lower, 0.12 and 0.09 mug m-2 min-1, respectively. Twelve significant NMVOCs were identified in lagoon samples (ethanol, 2-ethyl-1-hexanol, methanol, acetaldehyde, decanal, heptanal, hexanal, nonanal, octanal, acetone, methyl ethyl ketone, and 4-methylphenol). The overall average fluxes for these NMVOCs, ranged from 0.08 mug m-2 min-1 (4-methylphenol) to 2.11 mug m-2 min-1 (acetone). Seasonal H2S barn concentrations ranged from 72-631 ppb. DMS and DMDS seasonal concentrations were 2-3 orders of magnitude lower. There were six significant NMVOCs identified in barn samples (methanol, ethanol, acetone 2-3 butanedione, acetaldehyde and 4-methylphenol). Their overall average NMVOCs concentrations ranged from 2.87 ppb (4-methylphenol) to 16.21 ppb (ethanol). The overall average barn normalized emissions were 3.3 g day-1 AU-1 (AU (animal unit) = 500 kg) for H2S, 0.018 g day-1 AU-1 for DMS and 0.037 g day -1 AU-1 for DMDS. Normalized overall average NMVOC emissions ranged from 0.45 g day-1 AU-1 for ethanol to 0.16 g day-1 AU-1 for acetaldehyde. Barn H2S concentrations were generally one to two orders of magnitude above their odor thresholds. DMDS concentrations also regularly exceeded the lower limit of an odor threshold. Four NMVOCs (2-3 butanedione, decanal, 4-methylphenol and nonanal) had barn concentrations exceeding an odor threshold. Using overall average lagoon and barn emissions, the emissions from swine CAFOs in North Carolina were estimated. H2S had the largest RSC emission with an estimated North Carolina emission of 1.46 million kg yr -1, which was ˜21% of total North Carolina H2S emissions. Ethanol was the NMVOC with the largest North Carolina emission with an emission of 206,367 kg yr-1.

Rumsey, Ian Cooper

6

Natural emissions of non-methane volatile organic compounds, carbon monoxide, and oxides of nitrogen from North America  

Microsoft Academic Search

The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are responsible for a major portion of the compounds, including non-methane volatile organic compounds (NMVOC), carbon monoxide (CO) and nitric oxide (NO), that determine tropospheric oxidant concentrations. Natural sources include soil microbes, vegetation, biomass burning, and lightning. These sources are

Alex Guenther; Chris Geron; Tom Pierce; Brian Lamb; Peter Harley; Ray Fall

2000-01-01

7

Mapping Asian anthropogenic emissions of non-methane volatile organic compounds to multiple chemical mechanisms  

NASA Astrophysics Data System (ADS)

An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. In this work, we developed an improved speciation framework to generate model-ready anthropogenic Asian NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs by using an explicit assignment approach and updated NMVOC profiles, based on the total NMVOC emissions in the INTEX-B Asian inventory for the year 2006. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Gridded emissions for eight chemical mechanisms are developed at 30 min × 30 min resolution using various spatial proxies and are provided through the website: http://mic.greenresource.cn/intex-b2006. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms.

Li, M.; Zhang, Q.; Streets, D. G.; He, K. B.; Cheng, Y. F.; Emmons, L. K.; Huo, H.; Kang, S. C.; Lu, Z.; Shao, M.; Su, H.; Yu, X.; Zhang, Y.

2013-12-01

8

Tempo-spatial variation of emission inventories of speciated volatile organic compounds from on-road vehicles in China  

NASA Astrophysics Data System (ADS)

Emission inventories of sixty-nine speciated non-methane volatile organic compounds (NMVOC) from on-road vehicles in China were estimated for the period of 1980-2005, using seven NMVOC emission profiles, which were summarized based on local and international measurements from published literatures dealing with specific vehicle categories running under particular modes. Results show an exponential growth trend of China's historical emissions of alkanes, alkenes, alkines, aromatics and carbonyls during the period of 1980-2005, increasing from 63.9, 39.3, 6.9, 36.8 and 24.1 thousand tons, respectively, in 1980 to 2781.4, 1244.9, 178.5, 1350.7 and 403.3 thousand tons, respectively, in 2005, which coincided well with China's economic growth. Emission inventories of alkenes, aromatics and carbonyls were gridded at a high resolution of 40 km×40 km for air quality simulation and health risk evaluation, using the geographic information system (GIS) methodology. Spatial distribution of speciated NMVOC emissions shows a clear difference in emission densities between developed eastern and relatively underdeveloped western and inland China. Besides, the appearance and expansion of high-emission areas was another notable characteristic of spatial distribution of speciated NMVOC emissions during the period. Emission contributions of vehicle categories to speciated NMVOC groups showed annual variation, due to the variance in the provincial emissions and in the relative fractions of the seven emission profiles adopted at the provincial level. Highly reactive and toxic compounds accounted for high proportions of emissions of speciated NMVOC groups. The most abundant compounds were isopentane, pentane and butane from alkanes; ethene, propene, 2-methyl-2-butene and ethyne from alkenes and alkines; benzene, toluene, ethylbenzene, o-xylene, and m,p-xylene (BTEX) and 1,2,4-trimethylbenzene from aromatics and formaldehyde, acetaldehyde, benzaldehyde, acetone and acrolein from carbonyls.

Cai, H.; Xie, S. D.

2009-05-01

9

Tempo-spatial variation of emission inventories of speciated volatile organic compounds from on-road vehicles in China  

NASA Astrophysics Data System (ADS)

Emission inventories of sixty-seven speciated non-methane volatile organic compounds (NMVOC) from on-road vehicles in China were estimated for the period of 1980-2005, using seven NMVOC emission profiles, which were summarized based on local and international measurements from published literatures dealing with specific vehicle categories running under particular modes. Results show an exponential growth trend of China's historical emissions of alkanes, alkenes, alkines, aromatics and carbonyls during the period of 1980-2005, increasing from 63.9, 39.3, 6.9, 36.8 and 24.1 thousand tons, respectively, in 1980 to 2778.2, 1244.5, 178.7, 1351.7 and 406.0 thousand tons, respectively, in 2005, which coincided well with China's economic growth. Emission inventories of alkenes, aromatics and carbonyls were gridded at a high resolution of 40 km×40 km for air quality simulation and health risk evaluation, using the geographic information system (GIS) methodology. Spatial distribution of speciated NMVOC emissions shows a clear difference in emission densities between developed eastern and relatively underdeveloped western and inland China. Besides, the appearance and expansion of high-emission areas was another notable characteristic of spatial distribution of speciated NMVOC emissions during the period. Emission contributions of vehicle categories to speciated NMVOC groups showed annual variation, due to the variance in the provincial emissions and in the relative fractions of the seven emission profiles adopted at the provincial level. Highly reactive and toxic compounds accounted for high proportions of emissions of speciated NMVOC groups. The most abundant compounds were isopentane, pentane and butane from alkanes; ethene, propene, 2-methyl-2-butene and ethyne from alkenes and alkines; benzene, toluene, ethylbenzene, o-xylene, and m,p-xylene (BTEX) and 1,2,4-trimethylbenzene from aromatics and formaldehyde, acetaldehyde, benzaldehyde and acetone from carbonyls.

Cai, H.; Xie, S. D.

2009-09-01

10

Emissions of nonmethane volatile organic compounds from open crop residue burning in the Yangtze River Delta region, China  

NASA Astrophysics Data System (ADS)

crop residue burning is one of the major sources of air pollutants including the precursors of photooxidants like ozone and secondary organic aerosol. We made measurements of trace gases including nonmethane volatile organic compounds (NMVOCs) in a rural area in central East China in June 2010. During the campaign, we identified six biomass burning events in total through the simultaneous enhancement of carbon monoxide and acetonitrile. Four cases represented fresh plumes (<2 h after emission), and two cases represented aged plumes (>3 h after emission), as determined by photochemical age. While we were not able to quantify formic acid, we identified an enhancement of major oxygenated volatile organic compounds (OVOCs) as well as low molecular alkanes and alkenes, and aromatic hydrocarbons in these plumes. The observed normalized excess mixing ratios (NEMRs) of OVOCs and alkenes showed dependence on air mass age, even in fresh smoke plumes, supporting the view that these species are rapidly produced and destructed, respectively, during plume evolution. Based on the NEMR data in the fresh plumes, we calculated the emission factors (EFs) of individual NMVOC. The comparison to previous reports suggests that the EFs of formaldehyde and acetic acid have been overestimated, while those of alkenes have been underestimated. Finally, we suggest that open burning of wheat residue in China releases about 0.34 Tg NMVOCs annually. If we applied the same EFs to all crops, the annual NMVOC emissions would be 2.33 Tg. The EFs of speciated NMVOCs can be used to improve the existing inventories.

Kudo, Shinji; Tanimoto, Hiroshi; Inomata, Satoshi; Saito, Shinji; Pan, Xiaole; Kanaya, Yugo; Taketani, Fumikazu; Wang, Zifa; Chen, Hongyan; Dong, Huabin; Zhang, Meigen; Yamaji, Kazuyo

2014-06-01

11

Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions  

NASA Astrophysics Data System (ADS)

Non-methane volatile organic compounds (NMVOCs) influence air quality and global climate change through their effects on secondary air pollutants and climate forcers. Here we simulate the air quality and radiative forcing (RF) impacts of changes in ozone, methane, and sulfate from halving anthropogenic NMVOC emissions globally and from 10 regions individually, using a global chemical transport model and a standalone radiative transfer model. Halving global NMVOC emissions decreases global annual average tropospheric methane and ozone by 36.6 ppbv and 3.3 Tg, respectively, and surface ozone by 0.67 ppbv. All regional reductions slow the production of PAN, resulting in regional to intercontinental PAN decreases and regional NOx increases. These NOx increases drive tropospheric ozone increases nearby or downwind of source regions in the Southern Hemisphere (South America, Southeast Asia, Africa, and Australia). Some regions' NMVOC emissions contribute importantly to air pollution in other regions, such as East Asia, Middle East, and Europe, whose impact on US surface ozone is 43%, 34%, and 34% of North America's impact. Global and regional NMVOC reductions produce widespread negative net RFs (cooling) across both hemispheres from tropospheric ozone and methane decreases, and regional warming and cooling from changes in tropospheric ozone and sulfate (via several oxidation pathways). The total global net RF for NMVOCs is estimated as 0.0277 W m-2 (~1.8% of CO2 RF since the preindustrial). The 100 yr and 20 yr global warming potentials (GWP100, GWP20) are 2.36 and 5.83 for the global reduction, and 0.079 to 6.05 and -1.13 to 18.9 among the 10 regions. The NMVOC RF and GWP estimates are generally lower than previously modeled estimates, due to differences among models in ozone, methane, and sulfate sensitivities, and the climate forcings included in each estimate. Accounting for a~fuller set of RF contributions may change the relative magnitude of each region's impacts. The large variability in the RF and GWP of NMVOCs among regions suggest that regionally-specific metrics may be necessary to include NMVOCs in multi-gas climate trading schemes.

Fry, M. M.; Schwarzkopf, M. D.; Adelman, Z.; West, J. J.

2013-08-01

12

Effects of additional nonmethane volatile organic compounds, organic nitrates, and direct emissions of oxygenated organic species on global tropospheric chemistry  

Microsoft Academic Search

This work evaluates the sensitivity of tropospheric ozone and its precursors to the representation of nonmethane volatile organic compounds (NMVOCs) and organic nitrates. A global 3-D tropospheric chemistry\\/transport model (IMPACT) has been exercised initially using the GEOS-Chem chemical reaction mechanism. The model was then extended by adding emissions and photochemical reactions for aromatic and terpenoid hydrocarbons, and by adding explicit

Akinori Ito; Sanford Sillman; Joyce E. Penner

2007-01-01

13

Emission, speciation, and evaluation of impacts of non-methane volatile organic compounds from open dump site.  

PubMed

Surface emission from Dhapa, the only garbage disposal ground in Kolkata, is a matter of concern to the local environment and also fuels the issues of occupational and environmental health. Surface emission of the Dhapa landfill site was studied using a flux chamber measurement for nonmethane volatile organic compounds (NMVOCs). Eighteen noncarbonyl volatile organic compounds (VOCs) and 14 carbonyl VOCs, including suspected and known carcinogens, were found in appreciable concentrations. The concentrations of the target species in the flux chamber were found to be significantly higher for most of the species in summer than winter. Surface emission rate of landfill gas was estimated by using two different approaches to assess the applicability for an open landfill site. It was found that the emissions predicted using the model Land GEM version 3.02 is one to two orders less than the emission rate calculated from flux chamber measurement for the target species. Tropospheric ozone formation has a serious impact for NMVOC emission. The total ozone-forming potential (OFP) of the Dhapa dumping ground considering all target NMVOCs was estimated to be 4.9E+04 and 1.2E+05 g/day in winter and summer, respectively. Also, it was found that carbonyl VOCs play a more important role than noncarbonyl VOCs for tropospheric ozone formation. Cumulative cancer risk estimated for all the carcinogenic species was found to be 2792 for 1 million population, while the total noncancer hazard index (HI) was estimated to be 246 for the occupational exposure to different compounds from surface emission to the dump-site workers at Dhapa. Implications: This paper describes the real-time surface emission of NMVOCs from an open municipal solid waste (MSW) dump site studied using a flux chamber. Our study findings indicate that while planning for new landfill site in tropical meteorology, real-time emission data must be considered, rather than relying on modeled data. The formation of tropospheric ozone from emitted NMVOC has also been studied. Our result shows how an open landfill site acts as a source and adds to the tropospheric ozone for the airshed of a metropolitan city. PMID:25122957

Majumdar, Dipanjali; Ray, Sandipan; Chakraborty, Sucharita; Rao, Padma S; Akolkar, A B; Chowdhury, M; Srivastava, Anjali

2014-07-01

14

Space-based formaldehyde measurements as constraints on volatile organic compound emissions in east and south Asia and implications for ozone  

Microsoft Academic Search

We use a continuous 6-year record (1996–2001) of GOME satellite measurements of formaldehyde (HCHO) columns over east and south Asia to improve regional emission estimates of reactive nonmethane volatile organic compounds (NMVOCs), including isoprene, alkenes, HCHO, and xylenes. Mean monthly HCHO observations are compared to simulated HCHO columns from the GEOS-Chem chemical transport model using state-of-science, “bottom-up” emission inventories from

Tzung-May Fu; Daniel J. Jacob; Paul I. Palmer; Kelly Chance; Yuxuan X. Wang; Barbara Barletta; Donald R. Blake; Jenny C. Stanton; Michael J. Pilling

2007-01-01

15

Compilation and analyses of emissions inventories for the NOAA atmospheric chemistry project. Progress report, August 1997  

SciTech Connect

Global inventories of anthropogenic emissions of oxides of nitrogen for circa 1985 and 1990 and non-methane volatile organic compounds (NMVOCs) for circa 1990 have been compiled by this project. Work on the inventories has been carried out under the umbrella of the Global Emissions Inventory Activity of the International Global Atmospheric Chemistry program. Global emissions of NOx for 1985 are estimated to be 21 Tg N/yr, with approximately 84% originating in the Northern Hemisphere. The global emissions for 1990 are 31 Tg N/yr for NOx and 173 Gg NMVOC/yr. Ongoing research activities for this project continue to address emissions of both NOx and NMVOCs. Future tasks include: evaluation of more detailed regional emissions estimates and update of the default 1990 inventories with the appropriate estimates; derivation of quantitative uncertainty estimates for the emission values; and development of emissions estimates for 1995.

Benkovitz, C.M.

1997-09-01

16

COMPILATION AND ANALYSES OF EMISSIONS INVENTORIES FOR THE NOAA ATMOSPHERIC CHEMISTRY PROJECT. PROGRESS REPORT, AUGUST 1997.  

SciTech Connect

Global inventories of anthropogenic emissions of oxides of nitrogen (NO{sub x}) for circa 1985 and 1990 and Non-Methane Volatile Organic Compounds (NMVOCs) for circa 1990 have been compiled by this project. Work on the inventories has been carried out under the umbrella of the Global Emissions Inventory Activity (GEIA) of the International Global Atmospheric Chemistry (IGAC) Program. The 1985 NO{sub x} inventory was compiled using default data sets of global emissions that were refined via the use of more detailed regional data sets; this inventory is being distributed to the scientific community at large as the GEIA Version 1A inventory. Global emissions of NO{sub x} for 1985 are estimated to be 21 Tg N y{sup -1}, with approximately 84% originating in the Northern Hemisphere. The 1990 inventories of NO{sub x} and NMVOCs were compiled using unified methodologies and data sets in collaboration with the Netherlands National Institute of Public Health and Environmental Protection (Rijksinstituut Voor Volksgezondheid en Milieuhygiene, RIVM) and the Division of Technology for Society of the Netherlands Organization for Applied Scientific Research, (IMW-TNO); these emissions will be used as the default estimates to be updated with more accurate regional data. The NMVOC inventory was gridded and speciated into 23 chemical categories. The resulting global emissions for 1990 are 31 Tg N yr{sup -1} for NO{sub x} and 173 Gg NMVOC yr{sup -1}. Emissions of NO{sub x} are highest in the populated and industrialized areas of eastern North America and across Europe, and in biomass burning areas of South America, Africa, and Asia. Emissions of NMVOCs are highest in biomass burning areas of South America, Africa, and Asia. The 1990 NO{sub x} emissions were gridded to 1{sup o} resolution using surrogate data, and were given seasonal, two-vertical-level resolution and speciated into NO and NO{sub 2} based on proportions derived from the 1985 GEIA Version 1B inventory. Global NMVOC emissions were given additional species resolution by allocating the 23 chemical categories to individual chemical species based on factors derived from the speciated emissions of NMVOCs in the U.S. from the U.S. EPA's 1990 Interim Inventory. Ongoing research activities for this project continue to address emissions of both NO{sub x} and NMVOCs. Future tasks include: (a) evaluation of more detailed regional emissions estimates and update of the default 1990 inventories with the appropriate estimates, (b) derivation of quantitative uncertainty estimates for the emission values, and (c) development of emissions estimates for 1995.

BENKOVITZ,C.M.

1997-09-01

17

Volatile Organic Compound Emissions by Agricultural Crops  

NASA Astrophysics Data System (ADS)

Biogenic Volatile Organic Compounds (BVOCs) participate in ozone and aerosol formation, and comprise a substantial fraction of reactive VOC emission inventories. In the agriculturally intensive Central Valley of California, emissions from crops may substantially influence regional air quality, but emission potentials have not been extensively studied with advanced instrumentation for many important crops. Because crop emissions may vary according to the species, and California emission inventories are constructed via a bottom-up approach, a better knowledge of the emission rate at the species-specific level is critical for reducing uncertainties in emission inventories and evaluating emission model performance. In the present study we identified and quantified the BVOCs released by dominant agricultural crops in California. A screening study to investigate both volatile and semivolatile BVOC fractions (oxygenated VOCs, isoprene, monoterepenes, sesquiterpenes, etc.) was performed for 25 crop species (at least 3 replicates plants each), including branch enclosures of woody species (e.g. peach, mandarin, grape, pistachio) and whole plant enclosures for herbaceous species (e.g. onion, alfalfa, carrot), through a dynamic cuvette system with detection by PTRMS, in-situ GCMS/FID, and collection on carbon-based adsorbents followed by extraction and GCMS analysis. Emission data obtained in this study will allow inclusion of these crops in BVOC emission inventories and air quality simulations.

Ormeno, E.; Farres, S.; Gentner, D.; Park, J.; McKay, M.; Karlik, J.; Goldstein, A.

2008-12-01

18

Volatile organic compound emissions from Siberian larch  

NASA Astrophysics Data System (ADS)

We determined hourly emissions of isoprene, monoterpenes and sesquiterpenes from Siberian larch, one of the major tree species in Siberian forests. Summer volatile organic compounds (VOCs) emission from Siberian larch consisted mainly of monoterpenes (about 90%). The monoterpene emission spectrum remained constant during the measurement period, almost half was sabinene and other major monoterpenes were ?3-carene, ?- and ?-pinene. During spring and summer, about 10% of the VOCs were sesquiterpenes, mainly ?-farnesene. The sesquiterpene emissions declined to 3% in the fall. Isoprene, 2-methyl-3-buten-2-ol (MBO) and 1,8-cineole contributed to less than 3% of the VOC emission during the whole period. The diurnal variation of the emissions could be explained using a temperature-dependent parameterization. Emission potentials normalized to 30 °C were 5.2-21 ?g g dw-1 h -1 (using ?-value of 0.09 °C -1) for monoterpenes and 0.4-1.8 ?g g dw-1 h -1 (using ?-value of 0.143 °C -1, mean of determined values) for sesquiterpenes. Normalized monoterpene emission potentials were highest in late summer and elevated again in late fall. Sesquiterpene emission potentials were also highest in late summer, but decreased towards fall.

Ruuskanen, T. M.; Hakola, H.; Kajos, M. K.; Hellén, H.; Tarvainen, V.; Rinne, J.

19

High Arctic Biogenic Volatile Organic Compound emissions  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) emitted from terrestrial vegetation participate in oxidative reactions, affecting the tropospheric ozone concentration and the lifetimes of greenhouse gasses such as methane. Also, they affect the formation of secondary organic aerosols. BVOCs thus provide a strong link between the terrestrial biosphere, the atmosphere and the climate. Global models of BVOC emissions have assumed minimal emissions from the high latitudes due to low temperatures, short growing seasons and sparse vegetation cover. However, measurements from this region of the world are lacking and emissions from the High Arctic have not been published yet. The aim of this study was to obtain the first estimates for BVOC emissions from the High Arctic. Hereby, we wish to add new knowledge to the understanding of global BVOC emissions. Measurements were conducted in NE Greenland (74°30' N, 20°30' W) in four vegetation communities in the study area. These four vegetation communities were dominated by Cassiope tetragona, Salix arctica, Vaccinium uliginosum and Kobresia myosuroides/Dryas octopetela/Salix arctica, respectively. Emissions were measured by enclosure technique and collection of volatiles into adsorbent cartridges in August 2009. The volatiles were analyzed by gas chromatography-mass spectrometry following thermal desorption. Isoprene showed highest emissions in S. arctica-dominated heath, where it was the dominant single BVOC. However, isoprene emission decreased below detection limit in the end of August when the temperature was at or below 10°C. According to a principal component analysis, monoterpene and sesquiterpene emissions were especially associated with C. tetragona-dominated heath. Especially S. arctica and C. tetragona dominated heaths showed distinct patterns of emitted BVOCs. Emissions of BVOC from the studied high arctic heaths were clearly lower than the emissions observed previously in subarctic heaths with more dense vegetation and higher ambient temperature. However, high arctic BVOC emissions are expected to increase in the future as a result of the predicted pronounced climate warming effects in the High Arctic. Therefore, we suggest that further studies should be conducted to investigate the effects of climate changes in the region in order to gain new knowledge and understanding of future global BVOC emissions.

Schollert, Michelle; Buchard, Sebrina; Faubert, Patrick; Michelsen, Anders; Rinnan, Riikka

2013-04-01

20

Reduction of Volatile Organic Compound Emissions from Automobile Refinishing,  

National Technical Information Service (NTIS)

Automobile refinishing (repainting) is a source of volatile organic compound (VOC) emissions. The study was conducted to evaluate available techniques that can be used to reduce VOC emissions from this source. The document provides information on the step...

C. Athey, C. Hester, M. McLaughlin, R. M. Neulicht, M. B. Turner

1988-01-01

21

Non-methane volatile organic compounds in Africa: A view from space  

NASA Astrophysics Data System (ADS)

Isoprene emissions affect human health, air quality, and the oxidative capacity of the atmosphere. Globally anthropogenic non-methane volatile organic compounds (NMVOC) emissions are lower than that of isoprene, but local hotspots are hazardous to human health and air quality. In Africa the tropics are a large source of isoprene, while Nigeria appears as a large contributor to regional anthropogenic NMVOC emissions. I make extensive use of space-based formaldehyde (HCHO) observations from the Ozone Monitoring Instrument (OMI) and the chemical transport model (CTM) GEOS-Chem to estimate and examine seasonality of isoprene emissions across Africa, and identify sources and air quality consequences of anthropogenic NMVOC emissions in Nigeria. To estimate isoprene emissions I first developed a filtering scheme to remove (1) contamination from biomass burning and anthropogenic influences; and (2) displacement of HCHO from the isoprene emission source diagnosed with the GEOS-Chem CTM. Conversion to isoprene emissions is with NOx-dependent GEOS-Chem HCHO yields, obtained as the local sensitivity S of the HCHO column ?HCHO to a perturbation Delta in isoprene emissions EISOP (S = Delta?HCHO/DeltaE ISOP). The error in OMI-derived isoprene emissions is 40% at low levels of NOx and 40-90% under high-NOx conditions and is reduced by spatial and temporal averaging to the extent that errors are random. Weak isoprene emission seasonality in equatorial forests is driven predominantly by temperature, while large seasonality in northern and southern savannas is driven by temperature and leaf area index. The largest contribution of African isoprene emissions to surface ozone and particulate matter, determined with GEOS-Chem, of 8 ppbv and 1.5 ?g m-3, respectively, is over West Africa. The OMI HCHO data feature a large enhancement over Nigeria that is due to anthropogenic NMVOC emissions. With the OMI HCHO data, coincident satellite observations of atmospheric composition, aircraft measurements, and GEOS-Chem I estimate Nigerian NMVOC emissions that are higher per capita than China (5.7 Tg C a-1). Should Nigeria develop its electricity sector to sustain economic growth with local natural gas and coal reserves NO x emissions will exacerbate wintertime (December-February) surface ozone pollution that exceeds 90 ppbv due to poor ventilation and the Harmattan inversion layer.

Marais, Eloise Ann

22

Effects of additional nonmethane volatile organic compounds, organic nitrates, and direct emissions of oxygenated organic species on global tropospheric chemistry  

NASA Astrophysics Data System (ADS)

This work evaluates the sensitivity of tropospheric ozone and its precursors to the representation of nonmethane volatile organic compounds (NMVOCs) and organic nitrates. A global 3-D tropospheric chemistry/transport model (IMPACT) has been exercised initially using the GEOS-Chem chemical reaction mechanism. The model was then extended by adding emissions and photochemical reactions for aromatic and terpenoid hydrocarbons, and by adding explicit representation of hydroxy alkyl nitrates produced from isoprene. Emissions of methanol, phenol, acetic acid and formic acid associated with biomass burning were also added. Results show that O3 increases by 20% in most of the troposphere, peroxyacetyl nitrate (PAN) increases by 30% over much of the troposphere and OH increases by 10%. NOx (NO + NO2) decreases near source regions and increases in remote locations, reflecting increased transport of NOx away from source regions by organic nitrates. The increase in O3 was driven largely by the increased role of PAN as a transporter of NOx and by the rerelease of NOx from isoprene nitrates. The increased PAN production was associated with increases in methyl glyoxal and hydroxyacetone. Comparison with measured values show reasonable agreement for O3 and PAN, but model measurement agreement does not either improve or degrade in the extended model. The extended model shows improved agreement with measurements for methanol, acetic acid and peroxypropional nitrate (PPN). Results from the extended model were consistent with measured alkyl nitrates and glycolaldehyde, but hydroxyacetone and methyl glyoxal were overestimated. The latter suggests that the effect of the isoprene nitrates is somewhat smaller than estimated here. Although the model measurement comparison does not show specific improvements with the extended model, it provides a more complete description of tropospheric chemistry that we believe is important to include.

Ito, Akinori; Sillman, Sanford; Penner, Joyce E.

2007-03-01

23

Emissions of Oxygenated Volatile Organic Compounds from Plants Part I: Emissions from Lipoxygenase Activity  

Microsoft Academic Search

Emissions of oxygenated volatile organic compounds (OVOC) from several plant species were measured in continuously stirred tank reactors (CSTR). High emission pulses of OVOCs were observed when plants were exposed to stress. Absolute emission rates were highly variable ranging up to 10-13 mol · cm-2 · s-1. The temporal shape of these emissions was described by a formalism similar to

A. C. Heiden; K. Kobel; C. Langebartels; G. Schuh-Thomas; J. Wildt

2003-01-01

24

COMPOUND FORMS OF FOSSIL FUEL FLY ASH EMISSIONS  

EPA Science Inventory

A methodology for identifying inorganic compounds in particulate emissions from fossil fuel combustion processes is described. Samples collected from power plants burning coal and oil fuels of different compositions provided a typical range of fly ashes for the investigations. El...

25

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 ...

26

Compilation and analyses of emissions inventories for NOAA`s atmospheric chemistry project. Progress report, August 1997  

SciTech Connect

Global inventories of anthropogenic emissions of oxides of nitrogen (NO{sub x}) for circa 1985 and 1990 and Non-Methane Volatile Organic Compounds (NMVOCs) for circa 1990 have been compiled by this project. Work on the inventories has been carried out under the umbrella of the Global Emissions Inventory Activity (GEIA) of the International Global Atmospheric Chemistry (IGAC) Program. The 1985 NO{sub x} inventory was compiled using default data sets of global emissions that were refined via the use of more detailed regional data sets; this inventory is being distributed to the scientific community at large as the GEIA Version 1A inventory. Global emissions of NO{sub x} for 1985 are estimated to be 21 Tg N y{sup -1}, with approximately 84% originating in the Northern Hemisphere. The 1990 inventories of NO{sub x} and NMVOCs were compiled using unified methodologies and data sets in collaboration with the Netherlands National Institute of Public Health and Environmental Protection (Rijksinstituut Voor Volksgezondheid en Milieuhygiene, RIVM) and the Division of Technology for Society of the Netherlands Organization for Applied Scientific Research, (IMW-TNO); these emissions will be used as the default estimates to be updated with more accurate regional data. The NMVOC inventory was gridded and speciated into 23 chemical categories.

Benkovitz, C.M.; Mubaraki, M.A.

1997-09-01

27

Emission of volatile organic compounds (VOCs) from PVC floor coverings.  

PubMed

In this study 29 PVC floor coverings were tested for emission of vinyl chloride (VC) and other volatile organic compounds (VOCs). A study on the effect of higher temperature on emission of VOCs from newly manufactured PVC flooring was also carried out. The study was conducted in climatic chamber, according to Polish Standard PN-89/Z-04021. GC method was used for analyzing of the compounds emitted. VC was not emitted from any of the floorings tested. Other VOCs were emitted in different concentrations. The influence of temperature on emission was conducted at temperatures of 23 degrees C and 35 degrees C from 2 hrs up to 180 days after introduction of materials in the chamber. The increase of temperature caused increase of total volatile organic compounds (TVOC) emission during 24 hrs of experiment. Then the emission was comparable for both temperatures. After 9 days emission of identified and unidentified compounds (TVOC) showed a rapid decay and stayed on very low level during a few months. The study conducted showed that PVC floorings after 10 days of installation in the room should not be source of indoor air contamination. PMID:10431652

Wiglusz, R; Igielska, B; Sitko, E; Nikel, G; Jarnuszkiewicz, I

1998-01-01

28

Emission of charged particles from excited compound nucleus  

SciTech Connect

The formation and decay of excited compound nucleus are studied within the dinuclear system model[1]. The cross sections of complex fragment emission are calculated and compared with experimental data for the reactions {sup 3}He+{sup 108}Ag, {sup 78,82}Kr+{sup 12}C. Angular momentum dependence of cluster emission in {sup 78}Kr+{sup 12}C and {sup 40}Ca+{sup 78}Kr reactions is demonstrated.

Kalandarov, Sh. A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Nuclear Physics, Tashkent (Uzbekistan); Adamian, G. G.; Antonenko, N. V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

2010-11-24

29

Microscopic description of neutron emission rates in compound nuclei  

E-print Network

The neutron emission rates in thermal excited nuclei are conventionally described by statistical models with a phenomenological level density parameter that depends on excitation energies, deformations and mass regions. In the microscopic view of hot nuclei, the neutron emission rates can be determined by the external neutron gas densities without any free parameters. Therefore the microscopic description of thermal neutron emissions is desirable that can impact several understandings such as survival probabilities of superheavy compound nuclei and neutron emissivity in reactors. To describe the neutron emission rates microscopically, the external thermal neutron gases are self-consistently obtained based on the Finite-Temperature Hartree-Fock-Bogoliubov (FT-HFB) approach. The results are compared with the statistical model to explore the connections between the FT-HFB approach and the statistical model. The Skyrme FT-HFB equation is solved by HFB-AX in deformed coordinate spaces. Based on the FT-HFB approach...

Zhu, Yi

2014-01-01

30

Atmospheric nitrogen compounds II: emissions, transport, transformation, deposition and assessment  

Microsoft Academic Search

The Atmospheric Nitrogen Compounds II: Emissions, Transport, Transformation, Deposition and Assessment workshop was held in Chapel Hill, NC from 7 to 9 June 1999. This international conference, which served as a follow-up to the workshop held in March 1997, was sponsored by: North Carolina Department of Environment and Natural Resources; North Carolina Department of Health and Human Services, North Carolina

Viney P. Aneja; Paul A. Roelle; George C. Murray; James Southerland; Jan Willem Erisman; David Fowler; Willem A. H. Asman; Naveen Patni

2001-01-01

31

Inverting for Emissions of Ozone Precursors Using the Adjoint of a CTM  

NASA Astrophysics Data System (ADS)

In order to optimise the emissions of ozone precursors (CO, NOx, hydrocarbons) in the IMAGES global chemical transport model, we apply the adjoint technique. Misfits between modelled and measured concentrations are quantified by introducing the cost function and looking for a solution that corresponds to its minimum. The minimum of the cost function is calculated via an iterative procedure that makes use of the adjoint model operator, that is, the gradient of the cost function with respect to a set of control parameters to be optimised. The advantage of the adjoint model technique compared to other inversion methods is that no linear response of the calculated concentrations to changes in the emissions is assumed. Furthermore, the emissions of several chemical compounds can be varied and optimised simultaneously and the chemical feedbacks existing between different chemical compounds can be explicitly taken into account. These features are very important for compounds like CO and NOx which have common emission sources (like biomass burning), and are strongly inter-related through the chemistry of the OH radical. In the present study, the control parameters to be optimised are the annual emissions of CO, NOx and a few NMVOCs (ethane, propane and acetone) over large regions and for different broad categories. Making use of an emission inventory based on EDGAR 3 and GEIA, we present the results for emission optimisations performed using different combinations of the following observational datasets considered for the same year: ground-based measurements of CO and NMVOCs, MOPITT-derived CO columns, GOME-derived NO2 tropospheric columns, and aircraft measurements of several NMVOCs. Finally, the a posteriori concentrations are compared to independent observations provided by aircraft campaigns.

Muller, J.; Stavrakou, J.

2004-12-01

32

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

EPA Science Inventory

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

33

Volatile organic compound emissions from dry mill fuel ethanol production.  

PubMed

Ethanol fuel production is growing rapidly in the rural Midwest, and this growth presents potential environmental impacts. In 2002, the U.S. Environmental Protection Agency (EPA) and the Minnesota Pollution Control Agency (MPCA) entered into enforcement actions with 12 fuel ethanol plants in Minnesota. The enforcement actions uncovered underreported emissions and resulted in consent decrees that required pollution control equipment be installed. A key component of the consent decrees was a requirement to conduct emissions tests for volatile organic compounds (VOCs) with the goal of improving the characterization and control of emissions. The conventional VOC stack test method was thought to underquantify total VOC emissions from ethanol plants. A hybrid test method was also developed that involved quantification of individual VOC species. The resulting database of total and speciated VOC emissions from 10 fuel ethanol plants is relatively small, but it is the most extensive to date and has been used to develop and gauge compliance with permit limits and to estimate health risks in Minnesota. Emissions were highly variable among facilities and emissions units. In addition to the variability, the small number of samples and the presence of many values below detection limits complicate the analysis of the data. To account for these issues, a nested bootstrap procedure on the Kaplan-Meier method was used to calculate means and upper confidence limits. In general, the fermentation scrubbers and fluid bed coolers emitted the largest mass of VOC emissions. Across most facilities and emissions units ethanol was the pollutant emitted at the highest rate. Acetaldehyde, acetic acid, and ethyl acetate were also important emissions from some units. Emissions of total VOCs, ethanol, and some other species appeared to be a function of the beer feed rate, although the relationship was not reliable enough to develop a production rate-based emissions factor. PMID:17912928

Brady, Daniel; Pratt, Gregory C

2007-09-01

34

Biogenic volatile organic compound emissions from vegetation fires.  

PubMed

The aim of this paper was to provide an overview of the current state of the art on research into the emission of biogenic volatile organic compounds (BVOCs) from vegetation fires. Significant amounts of VOCs are emitted from vegetation fires, including several reactive compounds, the majority belonging to the isoprenoid family, which rapidly disappear in the plume to yield pollutants such as secondary organic aerosol and ozone. This makes determination of fire-induced BVOC emission difficult, particularly in areas where the ratio between VOCs and anthropogenic NOx is favourable to the production of ozone, such as Mediterranean areas and highly anthropic temperate (and fire-prone) regions of the Earth. Fire emissions affecting relatively pristine areas, such as the Amazon and the African savannah, are representative of emissions of undisturbed plant communities. We also examined expected BVOC emissions at different stages of fire development and combustion, from drying to flaming, and from heatwaves coming into contact with unburned vegetation at the edge of fires. We conclude that forest fires may dramatically change emission factors and the profile of emitted BVOCs, thereby influencing the chemistry and physics of the atmosphere, the physiology of plants and the evolution of plant communities within the ecosystem. PMID:24689733

Ciccioli, Paolo; Centritto, Mauro; Loreto, Francesco

2014-08-01

35

Reduction of volatile organic compound emissions from automobile refinishing  

SciTech Connect

Automobile refinishing (repainting) is a source of volatile organic compound (VOC) emissions. The study was conducted to evaluate available techniques that can be used to reduce VOC emissions from this source. The document provides information on the steps involved in the refinishing process which result in emissions, available emission reduction techniques, VOC emission levels, VOC emission reductions, and costs associated with the reduction techniques. Techniques investigated include (1) reduced-VOC cleaners, (2) replacement of lacquers with enamels, (3) replacement of enamels with polyurethanes, (4) replacement of solvent-borne primers with waterborne primers, (5) replacement of conventional clearcoats with higher-solids clearcoats, (6) installation of cleanup solvent recovery systems, (7) replacement of conventional spray guns with higher transfer efficiency equipment, and (8) add-on controls. The primary conclusions from the study are: (1) the use of available techniques could result in VOC emission reductions ranging from 3-50% of the current estimated baseline emissions from typical refinishing shops; and (2) the annualized costs for many of the available techniques are less than the cost of current practices.

Athey, C.; Hester, C.; McLaughlin, M.; Neulicht, R.M.; Turner, M.B.

1988-10-01

36

Microscopic description of neutron emission rates in compound nuclei  

E-print Network

The neutron emission rates in thermal excited nuclei are conventionally described by statistical models with a phenomenological level density parameter that depends on excitation energies, deformations and mass regions. In the microscopic view of hot nuclei, the neutron emission rates can be determined by the external neutron gas densities without any free parameters. Therefore the microscopic description of thermal neutron emissions is desirable that can impact several understandings such as survival probabilities of superheavy compound nuclei and neutron emissivity in reactors. To describe the neutron emission rates microscopically, the external thermal neutron gases are self-consistently obtained based on the Finite-Temperature Hartree-Fock-Bogoliubov (FT-HFB) approach. The results are compared with the statistical model to explore the connections between the FT-HFB approach and the statistical model. The Skyrme FT-HFB equation is solved by HFB-AX in deformed coordinate spaces. Based on the FT-HFB approach, the thermal properties and external neutron gas are properly described with the self-consistent gas substraction procedure. Then neutron emission rates can be obtained based on the densities of external neutron gases. The thermal statistical properties of $^{238}$U and $^{258}$U are studied in detail in terms of excitation energies. The thermal neutron emission rates in $^{238, 258}$U and superheavy compound nuclei $_{112}^{278}$Cn and $_{114}^{292}$Fl are calculated, which agree well with the statistical model by adopting an excitation-energy-dependent level density parameter. The coordinate-space FT-HFB approach can provide reliable microscopic descriptions of neutron emission rates in hot nuclei, as well as microscopic constraints on the excitation energy dependence of level density parameters for statistical models.

Yi Zhu; Junchen Pei

2014-09-13

37

Evaluation of Volatile Organic Compound Emissions from Megacities and Wildfires  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) play a critical role in determining air quality through their impact on ozone production and other pollutants. Tropospheric chemistry models use a variety of treatments for the lumping of VOCs in their chemical mechanisms, as a compromise between detailed treatment and computational speed. However, emission inventories are frequently provided for only total VOCs with little or no information on how to split the emissions among the model species, introducing additional uncertainty to the model simulations. Global model simulations using the Model for Ozone and Related Chemical Tracers (MOZART-4) and several different emission inventories are evaluated through detailed comparison to aircraft and surface observations. In particular, correlations between measured VOCs and CO are used to test the emission inventory emission ratios of the modeled VOC species. For example, megacity VOC emissions will be evaluated with surface measurements in Mumbai, Shanghai and Tokyo, as well as aircraft measurements from the NSF/MIRAGE experiment downwind of Mexico City. Wildfire emissions in Siberia, Canada and California will be evaluated using airborne observations of the NASA/ARCTAS experiment.

Emmons, L. K.; Apel, E. C.; Hornbrook, R. S.; Riemer, D. D.; Lamarque, J.; Wiedinmyer, C.; Mirage Science Team; Arctas Science Team

2011-12-01

38

Compound forms of fossil fuel fly ash emissions  

Microsoft Academic Search

A methodology for determining inorganic compounds present in particulate emissions from fossil fuel combustion processes is described. Samples collected from power plants burning oil and coal fuels of different composition provided a typical range of flyashes for the investigation. X-ray diffraction, Fourier transform infrared, and chemical-phase analyses were performed to determine elemental compositions of samples. Water-soluble sulfates are the predominant

William M. Henry; Kenneth T. Knapp

1980-01-01

39

Emission of Volatile Sulfur Compounds from Spruce Trees 1  

PubMed Central

Spruce (Picea Abies L.) trees from the same clone were supplied with different, but low, amounts of plant available sulfate in the soil (9.7-18.1 milligrams per 100 grams of soil). Branches attached to the trees were enclosed in a dynamic gas exchange cuvette and analyzed for the emission of volatile sulfur compounds. Independent of the sulfate supply in the soil, H2S was the predominant reduced sulfur compound continuously emitted from the branches with high rates during the day and low rates in the night. In the light, as well as in the dark, the rates of H2S emission increased exponentially with increasing water vapor flux from the needles. Approximately 1 nanomole of H2S was found to be emitted per mole of water. When stomata were closed completely, only minute emission of H2S was observed. Apparently, H2S emission from the needles is highly dependent on stromatal aperture, and permeation through the cuticle is negligible. In several experiments, small amounts of dimethylsulfide and carbonylsulfide were also detected in a portion of the samples. However, SO2 was the only sulfur compound consistently emitted from branches of spruce trees in addition to H2S. Emission of SO2 mainly proceeded via an outburst starting before the beginning of the light period. The total amount of SO2 emitted from the needles during this outburst was correlated with the plant available sulfate in the soil. The diurnal changes in sulfur metabolism that may result in an outburst of SO2 are discussed. PMID:16667315

Rennenberg, Heinz; Huber, Beate; Schröder, Peter; Stahl, Klaus; Haunold, Werner; Georgii, Hans-Walter; Slovik, Stefan; Pfanz, Hardy

1990-01-01

40

Emission and deposition of Nitrogen compounds in West Africa  

NASA Astrophysics Data System (ADS)

The atmospheric nitrogen budget depends on emission and deposition fluxes both as reduced and oxidized compounds. In West African ecosystems, data are scarce, and establishing a N budget is not an easy task. This work aims at linking data from diverse origins (surface, aircraft measurements, satellite data, modelling) to estimate emissions and deposition of N compounds in dry and wet savannas of West Africa, and to study their impact on atmospheric chemistry. In remote areas like in the Sahel, N oxidised compounds emissions are dominated by NO biogenic emissions from soils. N emissions from anthropogenic sources (biomass burning, domestic fires, fossil fuel) are less important, due to the low quantity of vegetation, and to the remoteness of big cities. N reduced compounds emissions are dominated by the release of NH3 from cattle dung. Biogenic NO emissions from soils have a direct impact on NOx and O3 concentration increase in the lower troposphere, as shown by results from aircraft and surface measurements, and from modelling (coupled dynamics/chemistry MESONH-C model, with on line emission derived from a neural network algorithm, where the NO flux is dependent on water field pore space, surface and deep soil temperature, sand percentage, pH, fertilization rate and wind speed), in the area of Niamey (Niger) in August 2006. In a second part of this work, estimated emissions of both oxidised and reduced N compounds are compared to estimate dry and wet deposition fluxes for the year 2006 in the Sahel region. The dry deposition flux is the product of modelled dry deposition velocity and the measured concentration. Concentrations have been measured in 3 stations located in dry savanna ecosystem) within the IDAF (IGAC/DEBITS/Africa) network, and dry deposition velocities have been modelled with the surface model ISBA. A first tentative of budget has been calculated for the year 2006, trying to integrate all potentially known sources and sinks in the region. Finally, the study has been extended in time and space; emissions from soils and fires have been calculated for the years 2002 to 2007, dry deposition velocities have been calculated within the same period in the 3 stations of dry savanna, plus 2 stations in wet savanna. The results show that the interannual variability in rainfall is responsible for changes in emission (both biogenic and anthropogenic) and deposition (dry and wet) fluxes, due to changes in soil moisture and temperature, LAI, and turbulence, linked to meteorological conditions. This study uses original and unique data from remote and hardly-ever-explored regions. The main conclusion of this work is that while often underestimated, savannas and seasonally dry ecosystems of the African continent play a significant role in the global nitrogen budget, and have a direct impact on the chemistry of the troposphere.

Delon, C.; Galy-Lacaux, C.; Adon, M.; Liousse, C.

2010-12-01

41

Modeling natural emissions in the Community Multiscale Air Quality (CMAQ) Model-I: building an emissions data base  

NASA Astrophysics Data System (ADS)

A natural emissions inventory for the continental United States and surrounding territories is needed in order to use the US Environmental Protection Agency Community Multiscale Air Quality (CMAQ) Model for simulating natural air quality. The CMAQ air modeling system (including the Sparse Matrix Operator Kernel Emissions (SMOKE) emissions processing system) currently estimates non-methane volatile organic compound (NMVOC) emissions from biogenic sources, nitrogen oxide (NOx) emissions from soils, ammonia from animals, several types of particulate and reactive gas emissions from fires, as well as sea salt emissions. However, there are several emission categories that are not commonly treated by the standard CMAQ Model system. Most notable among these are nitrogen oxide emissions from lightning, reduced sulfur emissions from oceans, geothermal features and other continental sources, windblown dust particulate, and reactive chlorine gas emissions linked with sea salt chloride. A review of past emissions modeling work and existing global emissions data bases provides information and data necessary for preparing a more complete natural emissions data base for CMAQ applications. A model-ready natural emissions data base is developed to complement the anthropogenic emissions inventory used by the VISTAS Regional Planning Organization in its work analyzing regional haze based on the year 2002. This new data base covers a modeling domain that includes the continental United States plus large portions of Canada, Mexico and surrounding oceans. Comparing July 2002 source data reveals that natural emissions account for 16% of total gaseous sulfur (sulfur dioxide, dimethylsulfide and hydrogen sulfide), 44% of total NOx, 80% of reactive carbonaceous gases (NMVOCs and carbon monoxide), 28% of ammonia, 96% of total chlorine (hydrochloric acid, nitryl chloride and sea salt chloride), and 84% of fine particles (i.e., those smaller than 2.5 ?m in size) released into the atmosphere. The seasonality and relative importance of the various natural emissions categories are described.

Smith, S. N.; Mueller, S. F.

2010-05-01

42

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

43

Sources and Controls on Oceanic Emission of Volatile Iodinated Compounds  

NASA Astrophysics Data System (ADS)

Volatile iodinated compounds (VICs) influence tropospheric and stratospheric chemistry and have globally significant impacts on the concentrations and lifetimes of climatically active gases. The atmospheric lifetimes of VICs vary substantially, reflecting not only the relative reactivity of each chemical species but also how far they may be transported vertically in the atmosphere. Semi-lagrangian, open ocean experiments allowed the rates of net change of several VICs to be determined in the sub-tropical open ocean. When combined with measured and modeled rates of loss from the water column, including photolysis, chemical transformation and air-sea exchange, the ';gross' production rates of several VICs can be estimated. We compare the production rates of polyhalogenated versus monohalogenated compounds in the open-ocean environments, in part to examine whether they may be derived from contrasting primary sources. Estimates of air-sea flux based on water-column measurements of concentration and wind-based transfer velocity parameterizations from several field campaigns allow the dominant VIC vectors of iodine to the marine boundary layer to be determined. How this water-column derived VIC air-sea flux compares in magnitude and composition to emissions of reactive iodine potentially generated by processes at the air-sea interface involving ozone and iodide is assessed.

Archer, S. D.; Smyth, T.; Stephens, J.; Nightingale, P. D.

2013-12-01

44

Identification of nonmethane organic compound emissions from grassland vegetation.  

SciTech Connect

Emissions of nonmethane organic compounds (NMOCs) from grassland vegetation were collected in Summa(reg.sign) passivated stainless-steel canisters with a static enclosure technique and were analyzed by high-resolution gas chromatography with flame ionization and ion trap mass spectrometric detectors. Approximately 40 NMOCs with 6-10 carbon atoms were observed in samples analyzed by high-resolution gas chromatography with the flame ionization detector. Nineteen NMOCs in this molecular weight range (6 aliphatic oxygenates; 1 aromatic hydrocarbon; and 4 acyclic, 5 monocyclic, and 3 bicyclic monoterpenoids) were identified by ion trap mass spectrometry. Mass spectrometry was particularly useful for identifying myrcene and cis-3-hexenylacetate, which coeluted on a fused-silica capillary column coated with a 1-{mu}m-thick film of polydimethylsiloxane. An evaluation of the reactivity of the grassland emissions revealed that the aliphatic oxygenates have lifetimes of a few hours with respect to oxidation by OH and O{sub 3} in the atmosphere. This value is similar to the lifetimes of the bicyclic monoterpenoids. The expected lifetimes of the monoterpenoids with respect to oxidation by NO{sub 3} are only several minutes.

Fukui, Y.; Doskey, P. V.; Environmental Research; NASA Ames Research Center

2000-01-01

45

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 the field site in a wind tunnel.

Koppmann, R.; Hoffmann, T.; Kesselmeier, J.; Schatzmann, M.

46

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

EPA Science Inventory

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

47

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

EPA Science Inventory

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

48

Predicting the emission rate of volatile organic compounds fromvinyl flooring  

SciTech Connect

A model for predicting the rate at which a volatile organic compound (VOC) is emitted from a diffusion-controlled material is validated for three contaminants (n-pentadecane, n-tetradecane, and phenol) found in vinyl flooring (VF). Model parameters are the initial VOC concentration in the material-phase (C{sub 0}), the material/air partition coefficient (K), and the material-phase diffusion coefficient (D). The model was verified by comparing predicted gas-phase concentrations to data obtained during small-scale chamber tests, and by comparing predicted material-phase concentrations to those measured at the conclusion of the chamber tests. Chamber tests were conducted with the VF placed top side up and bottom side up. With the exception of phenol, and within the limits of experimental precision, the mass of VOCs recovered in the gas phase balances the mass emitted from the material phase. The model parameters (C{sub 0}, K, and D) were measured using procedures that were completely independent of the chamber test. Gas- and material-phase predictions compare well to the bottom-side-up chamber data. The lower emission rates for the top-side-up orientation may be explained by the presence of a low-permeability surface layer. The sink effect of the stainless steel chamber surface was shown to be negligible.

Cox, Steven S.; Little, John C.; Hodgson, Alfred T.

2001-03-01

49

Atmospheric nitrogen compounds II: emissions, transport, transformation, deposition and assessment  

NASA Astrophysics Data System (ADS)

The Atmospheric Nitrogen Compounds II: Emissions, Transport, Transformation, Deposition and Assessment workshop was held in Chapel Hill, NC from 7 to 9 June 1999. This international conference, which served as a follow-up to the workshop held in March 1997, was sponsored by: North Carolina Department of Environment and Natural Resources; North Carolina Department of Health and Human Services, North Carolina Office of the State Health Director; Mid-Atlantic Regional Air Management Association; North Carolina Water Resources Research Institute; Air and Waste Management Association, RTP Chapter; the US Environmental Protection Agency and the North Carolina State University (College of Physical and Mathematical Sciences, and North Carolina Agricultural Research Service). The workshop was structured as an open forum at which scientists, policy makers, industry representatives and others could freely share current knowledge and ideas, and included international perspectives. The workshop commenced with international perspectives from the United States, Canada, United Kingdom, the Netherlands, and Denmark. This article summarizes the findings of the workshop and articulates future research needs and ways to address nitrogen/ammonia from intensively managed animal agriculture. The need for developing sustainable solutions for managing the animal waste problem is vital for shaping the future of North Carolina. As part of that process, all aspects of environmental issues (air, water, soil) must be addressed as part of a comprehensive and long-term strategy. There is an urgent need for North Carolina policy makers to create a new, independent organization that will build consensus and mobilize resources to find technologically and economically feasible solutions to this aspect of the animal waste problem.

Aneja, Viney P.; Roelle, Paul A.; Murray, George C.; Southerland, James; Erisman, Jan Willem; Fowler, David; Asman, Willem A. H.; Patni, Naveen

50

Reassessment of biogenic volatile organic compound emissions in the Atlanta area  

Microsoft Academic Search

Localized estimates of biogenic volatile organic compound (BVOC) emissions are important inputs for photochemical oxidant simulation models. Since forest tree species are the primary emitters of BVOCs, it is important to develop reliable estimates of their areal coverage and BVOC emission rates. A new system is used to estimate these emissions in the Atlanta area for specific tree genera at

Christopher D. Geron; Thomas E. Pierce; Alex B. Guenther

1995-01-01

51

Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry  

NASA Astrophysics Data System (ADS)

Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between approximately 500 and 825 Tg yr-1. The volatile olefinic compounds, such as isoprene and the monoterpenes, are thought to constitute the bulk of these emissions. However, it is becoming increasingly clear that a variety of partially oxidized hydrocarbons, principally alcohols, are also emitted. The available information concerning the terrestrial vegetation as sources of volatile organic compounds is reviewed. The biochemical processes associated with these emissions of the compounds and the atmospheric chemistry of the emitted compounds are discussed.

Fehsenfeld, Fred; Calvert, Jack; Fall, Ray; Goldan, Paul; Guenther, Alex B.; Hewitt, C. Nicholas; Lamb, Brian; Liu, Shaw; Trainer, Michael; Westberg, Hal; Zimmerman, Pat

1992-12-01

52

NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA  

EPA Science Inventory

The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are repsonsible for a major portion of the compounds, including non-methane volatile organic compounds (N...

53

75 FR 82363 - Approval and Promulgation of Implementation Plans; Ohio; Volatile Organic Compound Emission...  

Federal Register 2010, 2011, 2012, 2013

...FRL-9245-8] Approval and Promulgation of Implementation Plans; Ohio; Volatile Organic Compound Emission Control Measures for Lithographic and Letterpress Printing in Cleveland AGENCY: Environmental Protection Agency (EPA)....

2010-12-30

54

Speciation of volatile organic compound emissions for regional air quality modeling of particulate matter and ozone  

NASA Astrophysics Data System (ADS)

A new classification scheme for the speciation of organic compound emissions for use in air quality models is described. The scheme uses 81 organic compound classes to preserve both net gas-phase reactivity and particulate matter (PM) formation potential. Chemical structure, vapor pressure, hydroxyl radical (OH) reactivity, freezing point/boiling point, and solubility data were used to create the 81 compound classes. Volatile, semivolatile, and nonvolatile organic compounds are included. The new classification scheme has been used in conjunction with the Canadian Emissions Processing System (CEPS) to process 1990 gas-phase and particle-phase organic compound emissions data for summer and winter conditions for a domain covering much of eastern North America. A simple postprocessing model was used to analyze the speciated organic emissions in terms of both gas-phase reactivity and potential to form organic PM. Previously unresolved compound classes that may have a significant impact on ozone formation include biogenic high-reactivity esters and internal C6-8 alkene-alcohols and anthropogenic ethanol and propanol. Organic radical production associated with anthropogenic organic compound emissions may be 1 or more orders of magnitude more important than biogenic-associated production in northern United States and Canadian cities, and a factor of 3 more important in southern U.S. cities. Previously unresolved organic compound classes such as low vapour pressure PAHs, anthropogenic diacids, dialkyl phthalates, and high carbon number alkanes may have a significant impact on organic particle formation. Primary organic particles (poorly characterized in national emissions databases) dominate total organic particle concentrations, followed by secondary formation and primary gas-particle partitioning. The influence of the assumed initial aerosol water concentration on subsequent thermodynamic calculations suggests that hydrophobic and hydrophilic compounds may form external mixtures, and that separate treatment for these groups may be required in future air quality model simulations. The post-processing model used here overestimates the organic particle formation relative to measurements, lacks the complexity of a regional air quality model, and is not intended as an alternative to the latter. Results from the post-processing model do, however, provide guidance for the treatment of organic gases and particles in future air quality modeling work. Future air quality model simulations should attempt to speciate primary particulate organic compounds and include more detailed organic compound classes. Future emissions profile measurements should speciate gaseous high-molecular-mass organic compounds and primary organics emitted in particulate form (primary particle emissions are only available as a total particulate mass in currently available emissions data).

Makar, P. A.; Moran, M. D.; Scholtz, M. T.; Taylor, A.

2003-01-01

55

Emission, oxidation, and secondary organic aerosol formation of volatile organic compounds as observed at Chebogue Point,  

E-print Network

Emission, oxidation, and secondary organic aerosol formation of volatile organic compounds, methanol, and MEK measured by other in situ instrumentation. On the other hand these oxidized volatile show these compounds match the oxidation products of isoprene observed in smog chamber studies, and we

Silver, Whendee

56

Emissions of volatile organic compounds from vegetation and the implications for atmospheric chemistry  

Microsoft Academic Search

Vegetation provides a major source of reactive carbon entering the atmosphere. These compounds play an important role in (1) shaping global tropospheric chemistry, (2) regional photochemical oxidant formation, (3) balancing the global carbon cycle, and (4) production of organic acids which contribute to acidic deposition in rural areas. Present estimates place the total annual global emission of these compounds between

Fred Fehsenfeld; Jack Calvert; Ray Fall; Paul Goldan; A. B. Guenther; C. N. Hewitt; Brian Lamb; Shaw Liu; Michael Trainer; Hal Westberg; Pat Zimmerman

1992-01-01

57

HISTORIC EMISSIONS OF VOLATILE ORGANIC COMPOUNDS IN THE UNITED STATES FROM 1900 TO 1985  

EPA Science Inventory

The report gives an estimate of historic emissions of volatile organic compounds (VOCs) for each state (and the District of Columbia) of the contiguous U.S. Annual emissions were estimated on the national level from 1960 to 1985. For 1940, 1950, and every fifth year from 1960 to ...

58

The Complexity of Factors Driving Volatile Organic Compound Emissions by Plants  

Microsoft Academic Search

The emissions of volatile organic compounds, VOC, from plants have strong relevance for plant physiology, plant ecology, and atmospheric chemistry. We report here on the current knowledge of the many internal (genetic and biochemical) and external (abiotic - temperature, light, water availability, wind, ozone, and biotic - animal, plant and microorganisms interactions) factors that control emission rates of different VOC

J. Peñuelas; J. Llusià

2001-01-01

59

Patterns in volatile organic compound emissions along a savanna-rainforest gradient in central Africa  

Microsoft Academic Search

In temperate regions the chemistry of the lower troposphere is known to be significantly affected by biogenic volatile organic compounds (VOCs) emitted by plants. The chemistry of the lower troposphere over the tropics, however, is poorly understood, in part because of the considerable uncertainties in VOC emissions from tropical ecosystems. Present global VOC models predict that base emissions of isoprene

L. F. Klinger; J. Greenberg; A. Guenther; G. Tyndall; P. Zimmerman; J.-M. Moutsamboté; D. Kenfack

1998-01-01

60

Emission of charged particles from excited compound nuclei  

SciTech Connect

The process of complex fragment emission is studied within the dinuclear system model. Cross sections of complex fragment emission are calculated and compared with experimental data for the reactions {sup 3}He+{sup nat}Ag, {sup 78,86}Kr+{sup 12}C, and {sup 63}Cu+{sup 12}C. The mass distributions of the products of these reactions, isotopic distributions for the {sup 3}He+{sup nat}Ag and {sup 78}Kr+{sup 12}C reactions, and average total kinetic energies of the products of the {sup 78}Kr+{sup 12}C reaction are predicted.

Kalandarov, Sh. A.; Adamian, G. G. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, RU-141980 Moscow (Russian Federation); Institute of Nuclear Physics, Tashkent, UZ-702132 Tashkent (Uzbekistan); Antonenko, N. V. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, RU-141980 Moscow (Russian Federation); Scheid, W. [Institut fuer Theoretische Physik der Justus-Liebig-Universitaet, D-35392 Giessen (Germany)

2010-10-15

61

Membrane bioreactor for control of volatile organic compound emissions  

Microsoft Academic Search

A membrane bioreactor system that overcomes many of the limitations of conventional compost biofilters is described. The system utilizes microporous hydrophobic hollow fiber membranes for mass transfer of volatile organic compounds (VOCs) from the gas phase to a microbially active liquid phase. The reactor design provides a high biomass concentration, a method for wasting biomass, and a method for addition

Sarina J. Ergas; Michael S. McGrath

1997-01-01

62

Off-season biogenic volatile organic compound emissions from heath mesocosms: responses to vegetation cutting.  

PubMed

Biogenic volatile organic compounds (BVOCs) affect both atmospheric processes and ecological interactions. Our primary aim was to differentiate between BVOC emissions from above- and belowground plant parts and heath soil outside the growing season. The second aim was to assess emissions from herbivory, mimicked by cutting the plants. Mesocosms from a temperate Deschampsia flexuosa-dominated heath ecosystem and a subarctic mixed heath ecosystem were either left intact, the aboveground vegetation was cut, or all plant parts (including roots) were removed. For 3-5 weeks, BVOC emissions were measured in growth chambers by an enclosure method using gas chromatography-mass spectrometry. CO2 exchange, soil microbial biomass, and soil carbon and nitrogen concentrations were also analyzed. Vegetation cutting increased BVOC emissions by more than 20-fold, and the induced compounds were mainly eight-carbon compounds and sesquiterpenes. In the Deschampsia heath, the overall low BVOC emissions originated mainly from soil. In the mixed heath, root, and soil emissions were negligible. Net BVOC emissions from roots and soil of these well-drained heaths do not significantly contribute to ecosystem emissions, at least outside the growing season. If insect outbreaks become more frequent with climate change, ecosystem BVOC emissions will periodically increase due to herbivory. PMID:23966983

Rinnan, Riikka; Gierth, Diana; Bilde, Merete; Rosenørn, Thomas; Michelsen, Anders

2013-01-01

63

Off-season biogenic volatile organic compound emissions from heath mesocosms: responses to vegetation cutting  

PubMed Central

Biogenic volatile organic compounds (BVOCs) affect both atmospheric processes and ecological interactions. Our primary aim was to differentiate between BVOC emissions from above- and belowground plant parts and heath soil outside the growing season. The second aim was to assess emissions from herbivory, mimicked by cutting the plants. Mesocosms from a temperate Deschampsia flexuosa-dominated heath ecosystem and a subarctic mixed heath ecosystem were either left intact, the aboveground vegetation was cut, or all plant parts (including roots) were removed. For 3–5 weeks, BVOC emissions were measured in growth chambers by an enclosure method using gas chromatography-mass spectrometry. CO2 exchange, soil microbial biomass, and soil carbon and nitrogen concentrations were also analyzed. Vegetation cutting increased BVOC emissions by more than 20-fold, and the induced compounds were mainly eight-carbon compounds and sesquiterpenes. In the Deschampsia heath, the overall low BVOC emissions originated mainly from soil. In the mixed heath, root, and soil emissions were negligible. Net BVOC emissions from roots and soil of these well-drained heaths do not significantly contribute to ecosystem emissions, at least outside the growing season. If insect outbreaks become more frequent with climate change, ecosystem BVOC emissions will periodically increase due to herbivory. PMID:23966983

Rinnan, Riikka; Gierth, Diana; Bilde, Merete; Rosen?rn, Thomas; Michelsen, Anders

2013-01-01

64

Historical variations of biogenic volatile organic compound emission inventories in China, 1981-2003  

NASA Astrophysics Data System (ADS)

To evaluate the variations in temporal and spatial distribution of biogenic volatile organic compound (BVOC) emissions in China, historical BVOC emission inventories at a spatial resolution of 36 km × 36 km for the period of 1981-2003 were developed firstly. Based on the time-varying statistical data and Vegetation Atlas of China (1:1,000,000), emissions of isoprene, 37 monoterpenes, 32 sesquiterpenes, and other volatile organic compounds (OVOCs) were estimated using MEGANv2.1 driven by WRF model. Results show China's BVOC emissions had increased by 28.01% at an annual average rate of 1.27% from 37.89 Tg in 1981 to 48.50 Tg in 2003. Emissions of isoprene, monoterpenes, sesquiterpenes, and OVOCs had increased by 41.60%, 34.78%, 41.05%, and 4.89%, respectively. With fixed meteorological variables, the estimated BVOC emissions would increase by 19.25%, resulting from the increasing of vegetation biomass during the last 23 years. On average, isoprene, monoterpenes, sesquiterpenes, and OVOCs were responsible for 52.40%, 12.73%, 2.58%, and 32.29% of the national BVOC emissions, respectively. ?-pinene and ?-pinene, farnesene and caryophyllene were the largest contributors to the total monoterpene and sesquiterpene emissions, respectively. The highest emissions were found over northeastern, southeastern, southwestern China, Qinling Mountain, and Hainan and Taiwan provinces. The regions with high emissions had been expanding over the years, especially in the Changbai Mountain, southern China, and southwestern forest regions. The lowest emissions in southern China occurred in 1984-1988. Almost all the provinces had experienced increasing emissions, but their contributions to the national emissions differed significantly over the past 23 years. Yunnan, Guangxi, Heilongjiang, Jiangxi, Fujian, Guangdong, and Sichuan provinces always dominated the national BVOC emissions, excluding in 1977-1981, when the three northeastern provinces had relatively lower emissions.

Li, L. Y.; Xie, S. D.

2014-10-01

65

Dielectric barrier discharge carbon atomic emission spectrometer: universal GC detector for volatile carbon-containing compounds.  

PubMed

It was found that carbon atomic emission can be excited in low temperature dielectric barrier discharge (DBD), and an atmospheric pressure, low power consumption, and compact microplasma carbon atomic emission spectrometer (AES) was constructed and used as a universal and sensitive gas chromatographic (GC) detector for detection of volatile carbon-containing compounds. A concentric DBD device was housed in a heating box to increase the plasma operation temperature to 300 °C to intensify carbon atomic emission at 193.0 nm. Carbon-containing compounds directly injected or eluted from GC can be decomposed, atomized, and excited in this heated DBD for carbon atomic emission. The performance of this new optical detector was first evaluated by determination of a series of volatile carbon-containing compounds including formaldehyde, ethyl acetate, methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol, and absolute limits of detection (LODs) were found at a range of 0.12-0.28 ng under the optimized conditions. Preliminary experimental results showed that it provided slightly higher LODs than those obtained by GC with a flame ionization detector (FID). Furthermore, it is a new universal GC detector for volatile carbon-containing compounds that even includes those compounds which are difficult to detect by FID, such as HCHO, CO, and CO2. Meanwhile, hydrogen gas used in conventional techniques was eliminated; and molecular optical emission detection can also be performed with this GC detector for multichannel analysis to improve resolution of overlapped chromatographic peaks of complex mixtures. PMID:24328147

Han, Bingjun; Jiang, Xiaoming; Hou, Xiandeng; Zheng, Chengbin

2014-01-01

66

Comparison of carbonyl compounds emissions from diesel engine fueled with biodiesel and diesel  

NASA Astrophysics Data System (ADS)

The characteristics of carbonyl compounds emissions were investigated on a direct injection, turbocharged diesel engine fueled with pure biodiesel derived from soybean oil. The gas-phase carbonyls were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated silica cartridges from diluted exhaust and analyzed by HPLC with UV detector. A commercial standard mixture including 14 carbonyl compounds was used for quantitative analysis. The experimental results indicate that biodiesel-fueled engine almost has triple carbonyls emissions of diesel-fueled engine. The weighted carbonyls emission of 8-mode test cycle of biodiesel is 90.8 mg (kW h) -1 and that of diesel is 30.7 mg (kW h) -1. The formaldehyde is the most abundant compound of carbonyls for both biodiesel and diesel, taking part for 46.2% and 62.7% respectively. The next most significant compounds are acetaldehyde, acrolein and acetone for both fuels. The engine fueled with biodiesel emits a comparatively high content of propionaldehyde and methacrolein. Biodiesel, as an alternative fuel, has lower specific reactivity (SR) caused by carbonyls compared with diesel. When fueled with biodiesel, carbonyl compounds make more contribution to total hydrocarbon emission.

He, Chao; Ge, Yunshan; Tan, Jianwei; You, Kewei; Han, Xunkun; Wang, Junfang; You, Qiuwen; Shah, Asad Naeem

67

Emissions of non-methane organic compounds from a grassland site  

SciTech Connect

A mixture of oxygenated hydrocarbons (OxHCs), isoprene, and monoterpenes was detected in the emissions from a grassland site in the Midwestern United States. A plot dominated by crown vetch (Coronilla varia) and bluegrass (Poa spp.), exhibited a constant decrease in emissions of total non-methane organic compounds (NMOCs) from 580 {mu}g m{sup -2} hr{sup -1} in June 1992 to 150 {mu}g m{sup - 2} hr{sup -1} in October 1992, except for a slight increase in August. Oxygenated hydrocarbons (methanol, acetaldehyde, and acetone) and terpenes (isoprene, limonene, myrcene, {alpha}-pinene, and {beta}- pinene) composed about 90% and 10% of the identified NMOC emissions, respectively. Isoprene represented about 10% of the terpene emissions. Total NMOC emission rates based on vegetative biomass averaged 2.3 {mu}g g{sup -1} hr{sup -1}, with 10% of the identified NMOCs attributed to monoterpenes and the remainder mainly OxHCs. Over the course of the investigation, the relationship between the monoterpene emission rate and the temperature for a single plot was logarithmic and similar to the one between compound vapor pressure and temperature. However, emission rates normalized to temperature decreased throughout the summer and fall, indicating that parameterizations of emission rates from herbaceous plants must include a factor to compensate for environmental conditions such as soil moisture and nutrient deposition, which affect plant phenology and the seasonal pattern of species dominance.

Fukui, Yoshiko; Doskey, P.V.

1996-03-01

68

Emissions of Nonmethane Organic Compounds at an Illinois (USA) Landfill: Preliminary Field Measurements  

SciTech Connect

Current US regulatory models for estimating emissions of nonmethane organic compounds (NMOCs) from municipal solid waste (MSW) landfills require field validation to determine if the models are realistic. A project was initiated to begin to develop a field method for direct measurement of landfill NMOC emissions and, concurrently, develop improved sampling and analysis methods for individual NMOCs in landfill gas matrices. Two contrasting field sites at the Greene Valley Landfill, DuPage County, Illinois, USA, were established.

Bogner, J.; Spokas, K. [Argonne National Lab., IL (United States); Niemann, M.; Niemann, L. [Rust Environment and Infrastructure, Oak Brook, IL (United States); Baker, J. [WMX Technology Center, Geneva, IL (United States)

1997-08-01

69

Emissions of non-methane organic compounds from a grassland site  

Microsoft Academic Search

A mixture of oxygenated hydrocarbons (OxHCs), isoprene, and monoterpenes was detected in the emissions from a grassland site in the Midwestern United States. A plot dominated by crown vetch (Coronilla varia) and bluegrass (Poa spp.), exhibited a constant decrease in emissions of total non-methane organic compounds (NMOCs) from 580 μg m⁻² hr⁻¹ in June 1992 to 150 μg m{sup -

Yoshiko Fukui; P. V. Doskey

1996-01-01

70

NATURAL EMISSIONS OF NON-METHANE VOLATILE ORGANIC COMPOUNDS, CARBON MONOXIDE, AND OXIDES OF NITROGEN FROM NORTH AMERICA. (R825259)  

EPA Science Inventory

Abstract The magnitudes, distributions, controlling processes and uncertainties associated with North American natural emissions of oxidant precursors are reviewed. Natural emissions are responsible for a major portion of the compounds, including non-methane volatile o...

71

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

72

Cost effectiveness of introducing a new European evaporative emissions test procedure for petrol vehicles  

NASA Astrophysics Data System (ADS)

Evaporative emissions of non-methane volatile organic compounds (NMVOCs) arise from the vehicle's fuel system due to changes in ambient and vehicle temperatures, and contribute to urban smog. This paper presents an economic analysis of the societal costs and benefits of implementing a revised European evaporative emission test procedure for petrol vehicles under four scenarios for the period 2015-2040. The paper concludes that the most cost-effective option is the implementation of an aggressive purging strategy over 48 h and improved canister durability (scenario 2+). The average net benefit of implementing this scenario is €146,709,441 at a 6% discount rate. Per vehicle benefits range from €6-9 but when fuel savings benefits are added, total benefits range from €13-18. This is compared to average additional cost per vehicle of €9.

Haq, Gary; Martini, Giorgio; Mellios, Giorgos

2014-10-01

73

The contribution of evaporative emissions from gasoline vehicles to the volatile organic compound inventory in Mexico City.  

PubMed

The strategy for decreasing volatile organic compound emissions in Mexico has been focused much more on tailpipe emissions than on evaporative emissions, so there is very little information on the contribution of evaporative emissions to the total volatile organic compound inventory. We examined the magnitudes of exhaust and evaporative volatile organic compound emissions, and the species emitted, in a representative fleet of light-duty gasoline vehicles in the Metropolitan Area of Mexico City. The US "FTP-75" test protocol was used to estimate volatile organic compound emissions associated with diurnal evaporative losses, and when the engine is started and a journey begins. The amount and nature of the volatile organic compounds emitted under these conditions have not previously been accounted in the official inventory of the area. Evaporative emissions from light-duty vehicles in the Metropolitan Area of Mexico City were estimated to be 39 % of the total annual amount of hydrocarbons emitted. Vehicles built before 1992 (16 % of the fleet) were found to be responsible for 43 % of the total hydrocarbon emissions from exhausts and 31 % of the evaporative emissions of organic compounds. The relatively high amounts of volatile organic compounds emitted from older vehicles found in this study show that strong emission controls need to be implemented in order to decrease the contribution of evaporative emissions of this fraction of the fleet. PMID:24526614

Schifter, I; Díaz, L; Rodríguez, R; González-Macías, C

2014-06-01

74

Development and evaluation of a mass spectrometer-based continuous emission monitor for volatile organic compound emissions from combustion devices.  

PubMed

A mass spectrometer-based continuous emission monitor (MS-CEM) for organic compound emissions from combustion devices was developed and evaluated at the Louisiana State University (LSU) pilot-scale rotary kiln incinerator (RKI). The MS-CEM consists of a stack probe, heat-traced sampling line, vacuum pump, particulate filter, Nafion@ dryer and mass spectrometer. The mass spectrometer includes a computer that controls and optimizes the operation of the unit. The MS-CEM is capable of continuously analyzing up to 40 different volatile organic compounds on a real-time basis. The MS-CEM is capable of analyzing, computing and recording the analytical results for each and up to 40 different organic compounds in less than 0.3 s. Four different volatile organic compounds were mixed together and injected into the baghouse inlet while simultaneously analyzing each organic component exiting the RKI stack gas. The results obtained from MS-CEM were compared with the material balance values. The system response time (including the MS-CEM) varies from 1.1 to 1.5 min. PMID:11280990

Wada, E T; Sterling, A M

2001-01-01

75

The development of low volatile organic compound emission house—a case study  

Microsoft Academic Search

An aim in developing low volatile organic compound (VOCs) emission house is to reduce the level of VOCs in domestic housing. In this study, a case study for the reduction of exposure to VOCs from a newly constructed residential house was presented. Before application, the construction materials used in the house were tested in an environmental chamber and low VOC

H. Guo; F. Murray; S. C. Lee

2003-01-01

76

GASEOUS HC1 AND CHLORINATED ORGANIC COMPOUND EMISSIONS FROM REFUSE FIRED WASTE-TO-ENERGY SYSTEMS  

EPA Science Inventory

The emissions from a water wall mass fired municipal waste incinerator and a refuse derived fuel (RDF) fired incinerator were sampled for chlorinated organic compounds and hydrochloric acid (HCl). The sampling was performed to evaluate the extractive sampling methods used to meas...

77

EMISSION OF VOLATILE ORGANIC COMPOUNDS FROM DRUM-MIX ASPHALT PLANTS  

EPA Science Inventory

This research program was undertaken in order to develop a quantitative estimate of the emission of volatile organic compounds (VOCs) from drum-mix asphalt plants. The study was carried out by field sampling of five drum-mix plants under a variety of operating conditions. Include...

78

Diurnal and seasonal emissions of volatile organic compounds from cork oak ( Quercus suber) trees  

Microsoft Academic Search

The emissions of volatile organic compounds from Quercus suber (cork oak) were investigated at two rural sites in Portugal using a branch enclosure method with subsequent analysis by gas chromatography\\/flame ionization detection. Q. suber leaves released important amounts of monoterpenes, mainly in the form of limonene, ?-pinene, ?-pinene and sabinene. However, significant temporal and intraspecific variations in the relative abundance

C. A. Pio; P. A. Silva; M. A. Cerqueira; T. V. Nunes

2005-01-01

79

VOC (VOLATILE ORGANIC COMPOUNDS) FUGITIVE EMISSION DATA - HIGH DENSITY POLYETHYLENE PROCESS UNIT  

EPA Science Inventory

The report gives data from a 10-month study of volatile organic compound (VOC) fugitive emissions from a high density polyethylene process unit. It gives statistics on leak frequency, leak occurrence, and leak recurrence, with a leak defined as having a screening value equal to o...

80

EMISSIONS OF DIOXINS AND RELATED COMPOUNDS FROM COMBUSTION AND INCINERATION SOURCES  

EPA Science Inventory

This report on the emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans was prepared as a contribution to the Pilot Study on International Information Exchange on Dioxins and Related Compounds. he report describes the state of the art with respect to combustion and th...

81

BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM DESERT VEGETATION OF THE SOUTHWESTERN U.S.  

EPA Science Inventory

Thirteen common plant species in the Mojave and Sonoran Desert regions of the western United States were tested for emissions of biogenic non-methane volatile organic compounds (BVOCs). Only two of the species examined emitted isoprene at rates of 10 µgCg?1 ...

82

Oxidized and reduced biogenic nitrogen compound emissions into the rural troposphere: Characterization and modeling  

NASA Astrophysics Data System (ADS)

Using a dynamic flow-through chamber technique in conjunction with a state-of-the-art mobile laboratory, this research attempts to characterize and model oxidized and reduced biogenic nitrogen compound emissions into the rural troposphere. Nitrogen compound emissions are known to have profound effects on air quality. Consequences associated with increased emissions of oxidized and reduced nitrogen species are known to be increased tropospheric ozone production, fine particulate aerosol production, nitrate contamination of drinking water, eutrophication and acidification of soil and water bodies. It is well recognized that soil emissions can contribute a substantial percent of the total inventory for both the oxidized and reduced species, but great uncertainty still exists in this inventory. A controlled experiment involving the application of municipal waste biosolids to agricultural soils was shown to enhance NO emissions. A more detailed analysis throughout several seasons found the nitric oxide emissions from biosolid amended soils to have a strong temperature dependence and that their source strength is much larger relative to soils amended with chemically derived fertilizers. Emissions of nitric oxide from biosolid amended soils were modeled using the MultiScale Air Quality Simulation Platform (MAQSIP). Results from this model indicated that ozone concentrations can decrease by approximately 12% (in the evening) and increase by approximately 2% (during the daylight hours) when these biosolid amended soils are taken into consideration in the land use database. Emissions of ammonia from soils amended with swine waste effluent were also measured and modeled. This study revealed that while the average source strength of ammonia from soils is significantly smaller than that of the lagoons, the much larger surface area of the soils causes them to also be an important emissions source. A fundamental mechanistic mass transfer model is presented and discussed in terms of its applicability for estimating NH3 flux and was found to be an effective predictor of the NH3 emissions for time periods immediately following slurry application.

Roelle, Paul Andrew

2001-12-01

83

Flooding induced emissions of volatile signalling compounds in three tree species with differing waterlogging tolerance.  

PubMed

To gain insight into variations in waterlogging responsiveness, net assimilation rate, stomatal conductance, emissions of isoprene and marker compounds of anoxic metabolism ethanol and acetaldehyde, and stress marker compounds nitric oxide (NO), volatile products of lipoxygenase (LOX) pathway and methanol were studied in seedlings of temperate deciduous tree species Alnus glutinosa, Populus tremula and Quercus rubra (from highest to lowest waterlogging tolerance) throughout sustained root zone waterlogging of up to three weeks. In all species, waterlogging initially resulted in reductions in net assimilation and stomatal conductance and enhanced emissions of ethanol, acetaldehyde, NO, LOX products and methanol, followed by full or partial recovery depending on process and species. Strong negative correlations between g(s) and internal NO concentration and NO flux, valid within and across species, were observed throughout the experiment. Isoprene emission capacity was not related to waterlogging tolerance. Less waterlogging tolerant species had greater reduction and smaller acclimation capacity in foliage physiological potentials, and larger emission bursts of volatile stress marker compounds. These data collectively provide encouraging evidence that emissions of volatile organics and NO can be used as quantitative measures of stress tolerance and acclimation kinetics in temperate trees. PMID:20444211

Copolovici, Lucian; Niinemets, Ulo

2010-09-01

84

Volatile compounds emission from canopy fine litterfall in a hemiboreal mixed forest at Järvselja  

NASA Astrophysics Data System (ADS)

The seasonal distribution of biogenic volatile organic compounds (BVOC) emissions from canopy fine litterfall was investigated over a period of two years. Three stands of a hemiboreal mixed forest were studied. The stands presented different dominant tree species: (1) Norway spruce, (2) Scots pine, and (3) Silver birch and Downy birch. The litterfall was monthly collected in litter traps. The BVOC emission of litter was sampled by placing the litter into a glass jar equipped with a vent tube and pumping the head space air through a VOC adsorbing tube (carbotrap). Adsorbed BVOCs were analyzed in a GC-MS. Fifteen compounds were quantified. Seasonal differences in the total emission of BVOCs were found, defined by a maximum in summer and a minimum in autumn and winter. During summer months, litter emissions were dominated by limonene, ?-pinene, camphene and 3-carene in the three litter types, accounting for 70-75 % of total BVOC emitted in June. 3-Carene, ?-pinene and ?-pinene were the main compounds emitted during winter time, accounting for 50-60 % of total BVOC emitted in January. Stand to stand differences were assessed. The spruce and birch dominated stands showed more similarities in their BVOC emission pattern if compared to the pine dominated stand. Together with the litterfall data, an estimation of the annual total BVOC emitted by the soil litter layer is presented for each stand type.

Portillo-Estrada, Miguel; Noe, Beate; Noe, Steffen M.

2013-04-01

85

Aggregation and analysis of volatile organic compound emissions for regional modeling  

NASA Astrophysics Data System (ADS)

A general two-step procedure for aggregating the hundreds of reported volatile organic compounds (VOCs) into a much smaller set of lumped classes appropriate for regional airshed modeling is described. In the first step, the compounds are condensed into a manageable number of emission categories which could be adapted to a variety of molecularly-based lumped chemical mechanisms. In the second step, the emissions are further aggregated into a smaller set of VOC classes which directly correspond to those in a particular model's mechanism. The application of this procedure is illustrated by aggregating the National Acid Precipitation Assessment Program (NAPAP) anthropogenic VOC emissions inventory the U.S. first into the 32-class system, and then into the groups of model species used in the latest version of the Regional Acid Deposition Model (RADM2.0). The importance of different VOC categories and source types on regional pollution production is explored by comparing the contributions of each of the emissions groupings, RADM model species, and major emissions sources, to total moles carbon VOC reacted in model simulations. For this particular anthropogenic inventory and chemical mechanism, it is found that over 50% of the moles carbon reacted is associated with mobile sources. Such analysis can help indicate which uncertainties in anthropogenic emissions inventories may have the greatest impact on results of regional simulations.

Middleton, Paulette; Stockwell, William R.; Carter, William P. L.

86

Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming.  

PubMed

*Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. *We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. *The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5 degrees C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds. *The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects. PMID:20456056

Faubert, Patrick; Tiiva, Päivi; Rinnan, Asmund; Michelsen, Anders; Holopainen, Jarmo K; Rinnan, Riikka

2010-07-01

87

[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

88

Emission of reactive compounds and secondary products from wood-based furniture coatings  

NASA Astrophysics Data System (ADS)

Emissions of organic fragmentation products, so-called "secondary emission products" and reactive species from wood-based furniture coatings have been studied in 1 m 3 test chambers. the climatic conditions were representative of indoor environments. Relevant compounds and compound groups were the wetting agent 2,4,7,9-tetramethyl-5-dicyne-4,7-diol (T4MDD), the plasticiser di-2-ethyl-hexyl-phthalate (DEHP), aliphatic aldehydes, monoterpenes, photoinitiator fragments, acrylic monomers/reactive solvents and diisocyanate monomers. Such substances may affect human health in several ways. Aliphatic aldehydes and some photoinitiator fragments are of strong odour, while acrylates and diisocyanates cause irritation of skin, eyes and upper airways. Terpenes and reactive solvents like styrene undergo indoor chemistry in the presence of ozone, nitrogen oxides or hydroxy radicals. Secondary emission products and reactive species can achieve significant indoor concentrations. On the other hand, it has been reported that even small quantities can cause health effects. In the cases of indoor studies with special regard to emissions from furniture, chemical analysis should always include these compounds.

Salthammer, T.; Schwarz, A.; Fuhrmann, F.

89

Assessing methods to estimate emissions of non-methane organic compounds from landfills.  

PubMed

The non-methane organic compound (NMOC) emission rate is used to assess compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). A recent USEPA Report (EPA/600/R-11/033) employed a ratio method to estimate speciated NMOC emissions (i.e., individual NMOC emissions): speciated NMOC emissions=measured methane (CH4) emission multiplied by the ratio of individual NMOCs concentration relative to CH4 concentration (CNMOCs/ [Formula: see text] ) in the landfill header gas. The objectives of this study were to (1) evaluate the efficacy of the ratio method in estimating speciated NMOC flux from landfills; (2) determine for what types of landfills the ratio method may be in error and why, using recent field data to quantify the spatial variation of (CNMOCs/ [Formula: see text] ) in landfills; and (3) formulate alternative models for estimating NMOC emissions from landfills for cases in which the ratio method results in biased estimates. This study focuses on emissions through landfill covers measured with flux chambers and evaluates the utility of the ratio method for estimating NMOC emission through this pathway. Evaluation of the ratio method was performed using CH4 and speciated NMOC concentration and flux data from 2012/2013 field sampling of four landfills, an unpublished landfill study, and literature data from three landfills. The ratio method worked well for landfills with thin covers (<40cm), predicting composite NMOC flux (as hexane-C) to within a factor of 10× for 13 out of 15 measurements. However, for thick covers (?40cm) the ratio method overestimated NMOC emissions by ?10× for 8 out of 10 measurements. Alternative models were explored incorporating other chemical properties into the ratio method. A molecular weight squared (MW)(2)-modified ratio equation was shown to best address the tendency of the current ratio method to overestimate NMOC fluxes for thick covers. While these analyses were only performed using NMOC fluxes through landfill covers measured with flux chambers, results indicate the current USEPA approach for estimating NMOC emissions may overestimate speciated NMOC emission ?10× for many compounds. PMID:25108756

Saquing, Jovita M; Chanton, Jeffrey P; Yazdani, Ramin; Barlaz, Morton A; Scheutz, Charlotte; Blake, Don R; Imhoff, Paul T

2014-11-01

90

Biogenic Volatile Organic Compound Emission Rates From Urban Vegetation in Southeast China  

NASA Astrophysics Data System (ADS)

Currently, the country of China is growing economically at an extraordinary pace. With this growth comes an increase in emissions of anthropogenic pollutants such as hydrocarbons and nitrogen oxides from factories and vehicles. To accurately determine the effects of these pollutants on regional ozone production, and to best determine mitigation strategies, biogenic volatile organic compound (BVOC) emissions must be considered in regional atmospheric chemistry models. To date, few studies have been carried out to determine BVOC emission factors for plant species that occur in China. Considering that approximately 20% of the world's population resides in this region, it is important to develop accurate databases for BVOC emissions for the country of China. This experiment took place during May and June of 2005 and was based in the Fairy Lake Botanical Gardens (FLBG) located to the northeast of the city of Shenzhen. The city of Shenzhen is located in southeast China in Guangdong province. The city was designated a 'special economic zone' in 1980 and has experienced intense population and economic growth ever since. The dense city is surrounded by hilly rural areas of forest on three sides, and Hong Kong to the south. The purpose of the experiment was to evaluate emissions of BVOC from plants that are important to the Shenzhen region as well as to southeastern China. Over 150 species of plants were screened for emissions of isoprene and monoterpenes. These species include most of the dominant trees and shrubs planted in the Shenzhen area. Samples were collected at the FLBG as well as at various locations around the city of Shenzhen. BVOC emission samples were collected and analyzed in one of two ways. First, a Teflon enclosure was placed over a plant's branch with a constant flow of ambient air passing through the enclosure. Samples were then pumped into a Teflon bag for analysis. Samples were analyzed within 30 minutes by gas chromatography (GC) with either a photo ionization or flame ionization detector. Second, single plant leaves were placed into a light and temperature controlled leaf cuvette. Scrubbed air was passed through the cuvette, and was then collected on adsorbent cartridges for later analysis. Sample cartridges were returned to the US and analyzed by GC with a mass spectrometry for detection and identification of compounds. Results indicate a wide range of emissions for isoprene and monoterpenes. The observed emissions are compared with previous studies and taxonomic relationships are described. The emission rate measurements will be combined with detailed satellite-based landcover distribution database and used to characterize regional biogenic VOC emissions. In addition, the results of the emission survey will be used to identify low emitting plants that can be recommended for planting in subtropical urban areas.

Baker, B.; Graessli, M.; Bai, J.; Huang, A.; Li, N.; Guenther, A.

2005-12-01

91

European Biogenic Volatile Organic Compound emissions estimate using MEGAN v2.10  

NASA Astrophysics Data System (ADS)

Biogenic emissions estimations are essential to obtain a comprehensive understanding of both anthropogenic and biogenic contributions of the emissions. In this paper we have calculated the Biogenic Volatile Organic Compound (BVOC) emissions from vegetation over Europe using the newly developed Model of Emissions of Gases and Aerosols from Nature version 2.10 (MEGAN2.10). We performed a simulation of the entire year 2008 for a domain covering all Europe at a resolution of 30 x 30 km. The meteorological fields needed to calculate the BVOC emissions (surface temperature and shortwave radiation) were provided by a WRFv3.3 simulation (driven by NCEP/FNL global reanalysis data at 1° x 1°) and interfaced to MEGAN with MCIPv3.6. We used the global dataset provided with the MEGAN2.10 model containing the Plant Functional Types (PFT, at 0.5° x 0.5°), Leaf Area Indices (LAI, at 30s resolution) and Emission Factors (EF, at 0.01° x 0.01°). The motivation behind this study is to quantify the biogenic emissions as calculated from the new version of MEGAN over Europe for the entire annual cycle, and in second step to quantify the impact of biogenic emissions on air quality, using the Community Multiscale Air Quality model (CMAQ). Isoprene emissions comprise about half of the total global biogenic volatile organic compound (BVOC) estimated using MEGAN2.10, while all Terpenes comprise about 18% of the estimated total global BVOC emissions. Our simulations showed that Isoprene emissions are ranging from 10.7 Gg/month in December to 6572.8 Gg/month over Europe in July, while Terpenes emissions range from 38 Gg/month in January and 1598.23 Gg/month in July. Around 15 Tg/year and 5 Tg/year are estimated as total annual emissions of Isoprene and Terpenes, respectively. In comparison with a previous study using the Natural Emission Model (NEMO), for the same period and the similar domain and resolution, for July we found 70% higher Isoprene emissions and 30% lower Terpenes emissions. The difference between the two models estimates could be related to using specific regional EFs and PFTs for NEMO while a global dataset was used in our study, and also to the differences in the meteorological simulations. This is the first study quantifying biogenic emissions over Europe for one entire year with the new MEGAN version. This study will present our results in light of previous findings and, in order to understand the large uncertainty related to BVOC emissions and their impacts on air quality, we will show as well the results from CMAQ model for the summer 2008 episode using BVOC emissions from both MEGAN2.10 and NEMO models.

Dawoud, M.; Pozzoli, L.; Unal, A.; Kindap, T.; Poupkou, A.; Katragou, E.; Melas, D.

2013-12-01

92

Substrate-induced volatile organic compound emissions from compost-amended soils  

Microsoft Academic Search

The agronomic effects of composts, mineral fertiliser and combinations thereof on chemical, biological and physiological soil\\u000a properties have been studied in an 18-year field experiment. The present study aimed at tracing treatment effects by evaluating\\u000a the volatile organic compound (VOC) emission of the differently treated soils: non-amended control, nitrogen fertilisation\\u000a and composts (produced from organic waste and sewage sludge, respectively)

Martin S. A. Seewald; Wolfgang Singer; Brigitte A. Knapp; Ingrid H. Franke-Whittle; Armin Hansel; Heribert Insam

2010-01-01

93

Carbonyl Compounds and Toxicity Assessments of Emissions from a Diesel Engine Running on Biodiesels  

Microsoft Academic Search

This study elucidates the effect of biodiesel on the emission of carbonyl compounds generated from a diesel engine (generator), and the related biotoxicity characteristics. The Microtox test and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay were conducted to evaluate the acute toxicity and cytotoxicity, respectively, of gaseous extracts from diesel engine exhaust. The engine was tested using diesel fuel and biodiesel blends (10,

Yu-Yin Liu; Ta-Chang Lin; Ying-Jan Wang; Wei-Lun Ho; John Koupal; Fred Minassian; Hannah Murray; Mani Natarajan; Fenfen Zhu; Masaki Takaoka; Kazuyuki Oshita; Shinsuke Morisawa; Hiroshi Tsuno; Yoshinori Kitajima; Wan-Fu Chiang; Hung-Yuan Fang; Chao-Hsiung Wu; Chang-Jun Huang; Ching-Yuan Chang; Yu-Min Chang; Ching-Liang Chen; Anders Nielsen; Lars Nielsen; Anders Feilberg; Knud Christensen; Janet Yanowitz; Robert McCormick; Lei Yu; Shichen Jia; Qinyi Shi; Tsang-Jung Chang; Hong-Ming Kao; Yu-Ting Wu; Wei-Hua Huang; Patrick Goodman; David Rich; Ariana Zeka; Luke Clancy; Douglas Dockery; Thomas Lavery; Christopher Rogers; Ralph Baumgardner; Kevin Mishoe; Wei-Chin Chen; Hsun-Yu Lin; Chung-Shin Yuan; Chung-Hsuang Hung; Li He; Guo Huang; Guangming Zeng; Hongwei Lu

2009-01-01

94

Reassessment of biogenic volatile organic compound emissions in the Atlanta area  

NASA Astrophysics Data System (ADS)

Localized estimates of biogenic volatile organic compound (BVOC) emissions are important inputs for photochemical oxidant simulation models. Since forest tree species are the primary emitters of BVOCs, it is important to develop reliable estimates of their areal coverage and BVOC emission rates. A new system is used to estimate these emissions in the Atlanta area for specific tree genera at hourly and county levels. The U.S. Department of Agriculture, Forest Service Forest Inventory and Analysis data and an associated urban vegetation survey are used to estimate canopy occupancy by genus in the Atlanta area. A simple canopy model is used to adjust photosynthetically active solar radiation at five vertical levels in the canopy. Lraf temperature and photosynthetically active radiation derived from ambient conditions above the forest canopy are then used to drive empirical equations to estimate genus level emission rates of BVOCs vertically through forest canopies. These genera-level estimates are then aggregated to county and regional levels for input into air quality models and for comparison with (1) the regulatory model currently used and (2) previous estimates for the Atlanta area by local researchers. Estimated hourly emissions from the three approaches during a documented ozone event day are compared. The proposed model yields peak diurnal isoprene emission rates that are over a factor of three times higher than previous estimates. This results in total BVOC emission rates that are roughly a factor of two times higher than previous estimates. These emissions are compared with observed emissions from forests of similar composition. Possible implications for oxidant events are discussed.

Geron, Christopher D.; Pierce, Thomas E.; Guenther, Alex B.

95

Effects of nonmethane volatile organic compounds on microbial community of methanotrophic biofilter.  

PubMed

Effects of nonmethane volatile organic compounds (NMVOCs) on methanotrophic biofilter were investigated. Laboratory-scale biofilters packed with pumice and granular-activated carbon (10:1, w/w) were operated with CH4 and NMVOCs including dimethyl sulfide (DMS) and benzene/toluene (B/T). DMS alone exhibited a positive effect on the methanotrophic performance; however, the coexistence of B/T removed this effect. B/T alone exerted no effect on the performance. Pyrosequencing and quantitative PCR revealed that the NMVOCs strongly influenced the bacterial and methanotrophic communities but not the population density of methanotrophs. DMS alone diversified and changed both bacterial and methantrophic communities, but its effects were nullified by the presence of B/T. Canonical correspondence analysis revealed significant correlations between the NMVOCs and community composition and significant interaction between DMS and B/T. DMS did not affect the distribution of types I/II methanotrophs (60/40), while B/T increased the abundance of type I to 82 %. DMS and B/T favored the growth of the methanotrophic bacteria Methylosarcina and Methylomonas, respectively. These results suggest that NMVOCs can be a significant abiotic factor influencing methane biofiltration. PMID:23053093

Kim, Tae Gwan; Lee, Eun-Hee; Cho, Kyung-Suk

2013-07-01

96

Emissions of volatile organic compounds from new carpets measured in a large-scale environmental chamber  

SciTech Connect

This study was undertaken to quantify the emissions of volatile organic compounds (VOCs) released by new carpets. Samples of four typical carpets, including two with styrene-butadiene rubber (SBR) latex adhesive and two with different backings, were collected from the finish lines at manufacturers' mills. Individual VOCs released from these samples were identified, and their concentrations, emission rates and mass emissions were measured under simulated indoor conditions in a 20 m[sup 3] environmental chamber over one week periods. Concentrations and emission rates of VOCs emitted by a new SBR carpet were also measured in a house. The carpets emitted a variety of VOCs. The two SBR carpets primarily emitted 4-phenylcyclohexene (4-PCH), the source of [open quotes]new carpet[close quotes] odor, and styrene. The concentrations and emission rates of 4-PCH were similar for the two carpets, while the styrene values varied significantly. The carpet with a polyvinyl chloride backing emitted formaldehyde, vinyl acetate, isooctane, 1,2-propanediol, and 2-ethyl-1-hexanol. Of these, vinyl acetate and propanediol had the highest concentrations and emission rates. The carpet with a polyurethane backing primarily emitted butylated hydroxytoluene. With the exception of formaldehyde, little is known about the health effects of these VOCs at low concentrations. 23 refs., 3 figs., 6 tabs.

Hodgson, A.T.; Wooley, J.D.; Daisey, J.M. (Lawrence Berkeley Lab., CA (United States))

1993-03-01

97

Emission characteristics of particulate matter and volatile organic compounds in cow dung combustion.  

PubMed

Biomass fuel is used for cooking and heating, especially in developing countries. Combustion of biomass fuel can generate high levels of indoor air pollutants, including particulate matter (PM) and volatile organic compounds (VOCs). This study characterized PM and VOC emissions from cow dung combustion in a controlled experiment. Dung from grass-fed cows was dried and combusted using a dual-cone calorimeter. Heat fluxes of 10, 25, and 50 kW/m(2) were applied. The concentrations of PM and VOCs were determined using a dust spectrometer and gas chromatography/mass spectrometry, respectively. PM and VOC emission factors were much higher for the lower heat flux, implying a fire ignition stage. When the heat flux was 50 kW/m(2), the CO2 emission factor was highest and the PM and VOC emission factors were lowest. Particle concentrations were highest in the 0.23-0.3 ?m size range at heat fluxes of 25 and 50 kW/m(2). Various toxic VOCs, including acetone, methyl ethyl ketone, benzene, and toluene, were detected at high concentrations. Although PM and VOC emission factors at 50 kW/m(2) were lower, they were high enough to cause extremely high indoor air pollution. The characteristics of PM and VOC emissions from cow dung combustion indicated potential health effects of indoor air pollution in developing countries. PMID:24180364

Park, Duckshin; Barabad, Mona L; Lee, Gwangjae; Kwon, Soon-Bark; Cho, Youngmin; Lee, Duckhee; Cho, Kichul; Lee, Kiyoung

2013-11-19

98

Identification of polycyclic aromatic compounds in mutagenic emissions from steel casting.  

PubMed

Workers in ferrous foundries show increased risk of lung cancer. In the steel casting process hot metal is poured into sand moulds solidified with organic binders, producing a plume of smoke containing a variety of organic compounds and showing strong mutagenicity in the Salmonella/S9 assay. We have collected the emissions produced when steel is poured into an experimental sand mould solidified with oil, clay and cereal, a widely used binder system. The organic constituents of these emissions have been fractionated by preparative reverse-phase high performance liquid chromatography (HPLC) and mutagenic fractions have been analysed by capillary column gas chromatography/mass spectrometry (GC/MS). Of the 65 compounds for which mass spectra are reported, 54 have been tentatively identified as alkyl derivatives of polycyclic aromatic compounds. Many compounds of this class are known to be carcinogenic and mutagenic. In addition, several unsubstituted polycyclic aromatic hydrocarbons, including the carcinogenic benz[a]anthracene and benzo[a]pyrene, were found to be present. PMID:3160400

Quilliam, M A; Lant, M S; Kaiser-Farrell, C; McCalla, D R; Sheldrake, C P; Kerr, A A; Lockington, J N; Gibson, E S

1985-04-01

99

Variation in biogenic volatile organic compound emission pattern of Fagus sylvatica L. due to aphid infection  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) have been the focus of interest to understand atmospheric processes and their consequences in formation of ozone or aerosol particles; therefore, VOCs contribute to climate change. In this study, biogenic VOCs (BVOCs) emitted from Fagus sylvatica L. trees were measured in a dynamic enclosure system. In total 18 compounds were identified: 11 monoterpenes (MT), an oxygenated MT, a homoterpene (C 14H 18), 3 sesquiterpenes (SQT), isoprene and methyl salicylate. The frequency distribution of the compounds was tested to determine a relation with the presence of the aphid Phyllaphis fagi L. It was found that linalool, (E)-?-ocimene, ?-farnesene and a homoterpene identified as (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), were present in significantly more samples when infection was present on the trees. The observed emission spectrum from F. sylvatica L. shifted from MT to linalool, ?-farnesene, (E)-?-ocimene and DMNT due to the aphid infection. Sabinene was quantitatively the most prevalent compound in both, non-infected and infected samples. In the presence of aphids ?-farnesene and linalool became the second and third most important BVOC emitted. According to our investigation, the emission fingerprint is expected to be more complex than commonly presumed.

Joó, É.; Van Langenhove, H.; Šimpraga, M.; Steppe, K.; Amelynck, C.; Schoon, N.; Müller, J.-F.; Dewulf, J.

2010-01-01

100

Emission rates of selected volatile organic compounds from skin of healthy volunteers  

PubMed Central

Gas chromatography with mass spectrometric detection (GC–MS) coupled with solid phase micro-extraction as pre-concentration method (SPME) was applied to identify and quantify volatile organic compounds (VOCs) emitted by human skin. A total of 64 C4-C10 compounds were quantified in skin emanation of 31 healthy volunteers. Amongst them aldehydes and hydrocarbons were the predominant chemical families with eighteen and seventeen species, respectively. Apart from these, there were eight ketones, six heterocyclic compounds, six terpenes, four esters, two alcohols, two volatile sulphur compounds, and one nitrile. The observed median emission rates ranged from 0.55 to 4790 fmol cm?2 min?1. Within this set of analytes three volatiles; acetone, 6-methyl-5-hepten-2-one, and acetaldehyde exhibited especially high emission rates exceeding 100 fmol cm?2 min?1. Thirty-three volatiles were highly present in skin emanation with incidence rates over 80%. These species can be considered as potential markers of human presence, which could be used for early location of entrapped victims during Urban Search and Rescue Operations (USaR). PMID:24768920

Mochalski, Pawe?; King, Julian; Unterkofler, Karl; Hinterhuber, Hartmann; Amann, Anton

2014-01-01

101

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

102

Development of a material with reproducible emission of selected volatile organic compounds - ?-Chamber study.  

PubMed

Volatile organic compounds (VOCs) found indoors have the potential to affect human health. Typical sources include building materials, furnishings, cleaning agents, etc. To address this risk, chemical emission testing is used to assess the potential of different materials to pollute indoor air. One objective of the European Joint Research Project "MACPoll" (Metrology for Chemical Pollutants in Air) aims at developing and testing a reference material for the quality control of the emission testing procedure. Furthermore, it would enable comparison of measurement results between test laboratories. The heterogeneity of the majority of materials makes it difficult to find a suitable reference sample. In the present study, styrene, 2-ethyl-1-hexanol, N-methyl-?-pyrrolidone, lindane, n-hexadecane, 1,2-dimethyl- and 1,2-di-n-butyl-phthalate were added to 12 commercially available lacquers (6 alkyd and 6 acrylic polymer based lacquers) serving as carrier substrate. After homogenization, the mixtures were loaded into a Markes Micro-Chamber/Thermal Extractor (?-CTE™) for curing and investigation of the emission behavior for each compound. For almost all of the investigated chemicals, the preferred glossy acrylic lacquer showed emissions that were reproducible with a variation of less than 20% RSD. Such lacquer systems have therefore been shown to be good candidates for use as reference materials in inter-laboratory studies. PMID:24418066

Nohr, Michael; Horn, Wolfgang; Wiegner, Katharina; Richter, Matthias; Lorenz, Wilhelm

2014-07-01

103

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

PubMed Central

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

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

2014-01-01

104

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

PubMed

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

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

2014-04-01

105

Volatile organic compound emissions from switchgrass cultivars used as biofuel crops  

NASA Astrophysics Data System (ADS)

Volatile organic compound (VOC) emission rates during the growth and simulated harvest phases were determined for switchgrass ( Panicum virgatum) using laboratory chamber measurements. Switchgrass is a candidate for use in second-generation (cellulosic) biofuel production and the acreage 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 + another compound, most likely 1-penten-3-ol, 0.2 kg C ha -1 hexenals, and 0.1 kg C ha -1 hexenols. These emission rates are much lower than those expected from Eucalyptus or poplar plantations, which are other potential biofuel crops and have significantly higher VOC emissions, suggesting that the choice of species in the production of biofuels could have serious implications for regional air quality.

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

2011-06-01

106

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

107

Nitrogen compounds emission and deposition in West African ecosystems: comparison between wet and dry savanna  

NASA Astrophysics Data System (ADS)

Surface emission and deposition fluxes of reactive nitrogen compounds have been studied in five sites of West Africa during the period 2002 to 2007. Measurements of N deposition fluxes have been performed in IDAF sites representative of main west and central African ecosystems, i.e., 3 stations in dry savanna ecosystems (from 15° N to 12° N), and 2 stations in wet savanna ecosystems (from 9° N to 6° N). Dry deposition fluxes are calculated from surface measurements of NO2, HNO3 and NH3 concentrations and simulated deposition velocities, and wet deposition fluxes are calculated from NH4+ and NO3- concentration in samples of rain. Emission fluxes are evaluated including simulated NO biogenic emission from soils, emissions of NOx and NH3 from biomass burning and domestic fires, and volatilization of NH3 from animal excreta. This paper is a tentative to understand the eventual impact of the monsoon variability from year to year, with the natural variability of local sources, on the emission and deposition N fluxes, and to compare these evolutions between dry and wet savanna ecosystems. In dry savanna ecosystems where the rain season lasts mainly from June to September, the occurence of rain correlates with the beginning of emission and deposition fluxes. This link is less obvious in wet savanna ecosystems (wet season mainly from May to October), where the surface is less submitted to drastic changes in terms of water content. Whatever the location, the natural variability of rain from year to year does not exceed 15 %, and the variability of emission and deposition magnitude ranges between 15 % and 28 %. While quasi providing the same total N budget, and due to the presence of different types of soils and vegetation, wet and dry savanna do not present the same distribution in emission and deposition fluxes contributions: in dry savanna, the emission is dominated by ammonia volatilization, and the deposition is dominated by the dry contribution. In wet savanna, emission is equally distributed between ammonia volatilization, emissions from biomass burning and natural NO emissions from soils, and wet and dry deposition are equivalent. Due to the scarcity of available data on the African continent, and despite the numerous uncertainties resulting from the different calculations and assumptions, this work is a combination of data from different origins (surface measurements, satellite and modelling) to document the atmospheric Nitrogen cycle in tropical regions.

Delon, C.; Galy-Lacaux, C.; Adon, M.; Liousse, C.; Serça, D.; Diop, B.; Akpo, A.

2012-01-01

108

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.

109

Ozone formation potentials of organic compounds from different emission sources in the South Coast Air Basin of California  

NASA Astrophysics Data System (ADS)

Different organic compounds exhibit different propensities for ozone formation. Two approaches were used to study the ozone formation potentials or source reactivities of different anthropogenic organic compounds emission categories in California's South Coast Air Basin (SoCAB). The first approach was based on the combination of total organic gases (TOG) emission speciation profiles and the maximum incremental reactivity (MIR) scale of organic species. The second approach quantified ozone impacts from different emission sources by performing 3-dimensional air quality model sensitivity analysis involving increased TOG emissions from particular sources. The source reactivities derived from these two approaches agree reasonably well for 58 anthropogenic organic compounds emission categories in the SoCAB. Both approaches identify TOG emissions from mobile sources as having the highest reactivity. Source reactivities from both approaches were also combined with TOG emissions from each source category to produce a 2005 reactivity-based anthropogenic TOG emission inventory for the SoCAB. The top five reactivity-based anthropogenic TOG emission sources in the SoCAB during 2005 were: light-duty passenger cars, off-road equipment, consumer products, light-duty trucks category 2 (i.e., 3751-5750 lb), and recreational boats. This is in contrast to the mass-based TOG emission inventory, which indicates that livestock waste and composting emission categories were two of the five largest mass-based anthropogenic TOG emission sources. The reactivity-based TOG emission inventory is an important addition to the mass-based TOG emission inventory because it represents the ozone formation potentials from emission sources and can be used to assist in determining targeted sources for developing organic compounds reduction policies.

Chen, Jianjun; Luo, Dongmin

2012-08-01

110

Volatile organic compound emissions from green waste composting: Characterization and ozone formation  

NASA Astrophysics Data System (ADS)

Composting of green waste separated from the disposed solid waste stream reduces biodegradable inputs into landfills, and contributes valuable soil amendments to agriculture. Agencies in regions with severe air quality challenges, such as California's San Joaquin Valley (SJV), have raised concerns about gases emitted during the composting process, which are suspected to contribute to persistent high levels of ground-level ozone formation. The goal of the current study is to thoroughly characterize volatile organic compound (VOC) emissions from green waste compost piles of different ages (fresh tipped piles, 3-6 day old windrows, and 2-3 week old windrows). Multiple sampling and analytical approaches were applied to ensure the detection of most gaseous organic components emitted. More than 100 VOCs were detected and quantified in this study, including aliphatic alkanes, alkenes, aromatic hydrocarbons, biogenic organics, aldehydes, ketones, alcohols, furans, acids, esters, ether, halogenated hydrocarbons and dimethyl disulfide (DMDS). Alcohols were found to be the dominating VOC in the emissions from a compost pile regardless of age, with fluxes ranging from 2.6 to 13.0 mg m -2 min -1 with the highest emissions coming from the younger composting windrows (3-6 days). Average VOC emissions other than alcohols were determined to be 2.3 mg m -2 min -1 from younger windows, which was roughly two times higher than either the fresh tipping pile (1.2 mg m -2 min -1) or the older windrows (1.4 mg m -2 min -1). It was also observed that the older windrows emit a slightly larger proportion of more reactive compounds. Approximately 90% of the total VOCs were found to have maximum incremental reactivity of less than 2. Net ozone formation potential of the emissions was also assessed.

Kumar, Anuj; Alaimo, Christopher P.; Horowitz, Robert; Mitloehner, Frank M.; Kleeman, Michael J.; Green, Peter G.

2011-04-01

111

Nitrogen compounds emission and deposition in West African ecosystems: comparison between wet and dry savanna  

NASA Astrophysics Data System (ADS)

Surface emission and deposition fluxes of nitrogen compounds have been studied in five sites of West Africa during the period 2002 to 2007. Measurements of N deposition fluxes have been performed in IDAF sites representative of main west and central African ecosystems, i.e., 3 stations in dry savanna ecosystems (from 15° N to 12° N), and 2 stations in wet savanna ecosystems (from 9° N to 6° N). Dry deposition fluxes are calculated from surface measurements of NO2, HNO3 and NH3 concentrations and simulated deposition velocities, and wet deposition fluxes are calculated from NH4+ and NO3- concentration in samples of rain. Emission fluxes are evaluated including simulated NO biogenic emission from soils, emissions of NOx and NH3 from biomass burning and domestic fires, and volatilization of NH3 from animal excreta. This paper is a tentative to link the variability of rain and the intra and inter annual variability of emission and deposition processes, and to compare these evolutions between dry and wet savanna ecosystems. In dry savanna ecosystems where the rain season lasts mainly from June to September, the occurence of rain correlates with the beginning of emission and deposition fluxes. This link is less obvious in wet savanna ecosystems (wet season mainly from May to October), where the surface is less submitted to drastic changes in terms of water content. Whatever the location, the natural variability of rain from year to year does not exceed 15 %, and does not induce a strong impact on emission and deposition magnitude. Due to the scarcity of available data on the African continent, it is of first importance to combine data from different origins (surface measurements, satellite and modelling) to document the atmospheric Nitrogen cycle in these tropical regions.

Delon, C.; Galy-Lacaux, C.; Adon, M.; Liousse, C.; Serça, D.; Diop, B.; Akpo, A.

2011-07-01

112

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

113

Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft  

E-print Network

A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the ...

Herndon, S. C.

114

A NONSTEADY-STATE ANALYTICAL MODEL TO PREDICT GASEOUS EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM LANDFILLS. (R825689C072)  

EPA Science Inventory

Abstract A general mathematical model is developed to predict emissions of volatile organic compounds (VOCs) from hazardous or sanitary landfills. The model is analytical in nature and includes important mechanisms occurring in unsaturated subsurface landfill environme...

115

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

NASA Astrophysics Data System (ADS)

Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regions of the world to understand regional and global impacts and to implement possible mitigation strategies. The mixed deciduous and coniferous forests of northern Wisconsin, USA, were predicted to have significant VOC emission rates because they are comprised of many genera (i.e. Picea, Populus, Quercus, Salix) known to be high VOC emitters. In July 1993, a study was conducted on the Chequamegon National Forest near Rhinelander, WI, to identify and quantify VOC emitted from major trees, shrubs, and understory herbs in the mixed northern forests of this region. Emission rates were measured at various scales - at the leaf level with cuvettes, the branch level with branch enclosures, the canopy level with a tower based system, and the landscape level with a tethered balloon air sampling system. Area-average emission rates were estimated by scaling, using biomass densities and species composition along transects representative of the study site. Isoprene (C 5H 8) was the primary VOC emitted, although significant quantities of monoterpenes (C 10H 16) were also emitted. The highest emission rates of isoprene (at 30°C and photosynthetically active radiation of 1000 ?mol m -2 s -1) were from northern red oak ( Quercus rubra, >110 ?g(C) g -1 h -1); aspen ( Populus tremuloides, >77); willow ( Salix spp., >54); and black spruce ( Picea mariana, >10). Emission rates of hybrid poplar clones ranged from 40 to 90 ?g(C) g -1 h -1 at 25°C; those of Picea provenances were generally <10, and emission rates of a hybrid between North American and European spruces were intermediate to parental rates. More than 30 species of plants were surveyed from the sites, including several from previously unstudied genera such as Alnus, Chamaedaphne, Ledum, Tilia, Rubus, and Sphagnum. Based on the measured isoprene concentrations in the daytime atmospheric surface layer and mixed layer, area-averaged fluxes of isoprene were estimated to be about 1 mg(C) m -2 h -1. This estimate agrees reasonably well with model predictions. Our results indicate that mixed forests in the Lake States region of the USA are a significant source of reactive VOC to the atmosphere. Accurate estimates of these emissions are required for determining appropriate regulatory air pollution control strategies. Future studies are needed to extrapolate these estimates to other landscapes and to better understand the factors controlling observed variations in VOC emissions.

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

116

Characteristics of volatile organic compounds emission profiles from hot road bitumens.  

PubMed

A procedure for the investigation and comparison of volatile organic compounds (VOCs) emission profiles to the atmosphere from road bitumens with various degrees of oxidation is proposed. The procedure makes use of headspace analysis and gas chromatography with universal as well as selective detection, including gas chromatography-mass spectrometry (GC-MS). The studies revealed that so-called vacuum residue, which is the main component of the charge, contains variable VOC concentrations, from trace to relatively high ones, depending on the extent of thermal cracking in the boiler of the vacuum distillation column. The VOC content in the oxidation product, so-called oxidized paving bitumen, is similarly varied. There are major differences in VOC emission profiles between vacuum residue and oxidized bitumens undergoing thermal cracking. The VOC content in oxidized bitumens, which did not undergo thermal cracking, increases with the degree of oxidation of bitumens. The studies revealed that the total VOC content increases from about 120 ppm for the raw vacuum residue to about 1900 ppm for so-called bitumen 35/50. The amount of volatile sulfur compounds (VSCs) in the volatile fraction of fumes of oxidized bitumens increases with the degree of oxidation of bitumen and constitutes from 0.34% to 3.66% (w/w). The contribution of volatile nitrogen compounds (VNCs) to total VOC content remains constant for the investigated types of bitumens (from 0.16 to 0.28% (w/w) of total VOCs). The results of these studies can also find use during the selection of appropriate bitumen additives to minimize their malodorousness. The obtained data append the existing knowledge on VOC emission from oxidized bitumens. They should be included in reports on the environmental impact of facilities in which hot bitumen binders are used. PMID:24875867

Boczkaj, Grzegorz; Przyjazny, Andrzej; Kami?ski, Marian

2014-07-01

117

Study of the dynamics of induced emission from organic compounds under pulsed laser pumping  

NASA Astrophysics Data System (ADS)

A numerical modeling technique has been used to study the dynamics of generation of induced emission in a series of organic compounds: coumarin (7-amino-4-methylcoumarin and 6-bromo-3-(4-(4-bromophenyl) thiazole-2-yl)-coumarin) and rhodamine 6G. The effect of concentration on the lasing wavelength (rhodamine 6G) has been elucidated, along with the lasing capability of 7-amino-4-methylcoumarin at different pump pulse durations. The reasons for the absence of lasing in 6-bromo-3-(4-(4-bromophenyl)thiazole-2-yl)-coumarin have been investigated.

Kopylova, T. N.; Artyukhov, V. Ya.; Nikonov, S. Yu.; Gadirov, R. M.

2013-09-01

118

Angular distribution of light emission from compound-eye cornea with conformal fluorescent coating  

NASA Astrophysics Data System (ADS)

The complex morphology of the apposition compound eyes of insects of many species provides them a wide angular field of view. This characteristic makes these eyes attractive for bioreplication as artificial sources of light. The cornea of a blowfly eye was conformally coated with a fluorescent thin film with the aim of achieving wide field-of-view emission. On illumination by shortwave-ultraviolet light, the conformally coated eye emitted visible light whose intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

Martín-Palma, Raúl J.; Miller, Amy E.; Pulsifer, Drew P.; Lakhtakia, Akhlesh

2014-09-01

119

Characteristics of volatile organic compounds from motorcycle exhaust emission during real-world driving  

NASA Astrophysics Data System (ADS)

The number of motorcycles has increased significantly in Asia, Africa, Latin American and Europe in recent years due to their reasonable price, high mobility and low fuel consumption. However, motorcycles can emit significant amounts of air pollutants; therefore, the emission characteristics of motorcycles are an important consideration for the implementation of control measures for motorcycles in urban areas. Results of this study indicate that most volatile organic compound (VOC) emission factors were in the range of several decades mg/km during on-road driving. Toluene, isopentane, 1,2,4-trimethylbenzene, m,p-xylene, and o-xylene were the most abundant VOCs in motorcycle exhaust, with emission factors of hundreds mg/km. Motorcycle exhaust was 15.4 mg/km for 15 carbonyl species. Acetaldehyde, acetone, formaldehyde and benzaldehyde were the major carbonyl species, and their emission factors ranged from 1.4 to 3.5 mg/km 1,2,4-trimethylbenzene, m,p-xylene, 1-butene, toluene, o-xylene, 1,2,3-trimethylbenzene, propene, 1,3,5-trimethylbenzene, isoprene, m-diethylbenzene, and m-ethyltoluene were the main ozone formation potential (OFP) species, and their OFP was 200 mg-O3/km or higher.

Tsai, Jiun-Horng; Huang, Pei-Hsiu; Chiang, Hung-Lung

2014-12-01

120

Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation  

NASA Astrophysics Data System (ADS)

Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) and Gas Chromatography-Selective Ion Monitoring-Mass Spectrometry (GC-SIM-MS). Analysis of DNPH cartridges by GC-SIM-MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6050 and 2300 ?g MJ-1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3500 ?g MJ-1 in HFO operation to 1540 ?g MJ-1 in DF operation, which is 4-30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%).

Reda, Ahmed A.; Schnelle-Kreis, J.; Orasche, J.; Abbaszade, G.; Lintelmann, J.; Arteaga-Salas, J. M.; Stengel, B.; Rabe, R.; Harndorf, H.; Sippula, O.; Streibel, T.; Zimmermann, R.

2014-09-01

121

Non-methane biogenic volatile organic compound emissions from boreal peatland microcosms under warming and water table drawdown  

Microsoft Academic Search

Boreal peatlands have significant emissions of non-methane biogenic volatile organic compounds (BVOCs). Climate warming is expected to affect these ecosystems both directly, with increasing temperature, and indirectly, through water table drawdown following increased evapotranspiration. We assessed the combined effect of warming and water table drawdown on the BVOC emissions from boreal peatland microcosms. We also assessed the treatment effects on

Patrick Faubert; Paivi Tiiva; Tchamga Achille Nakam; Jarmo K. Holopainen; Toini Holopainen; Riikka Rinnan

2011-01-01

122

Qualitative and quantitative characterization of volatile organic compound emissions from cut grass  

PubMed Central

Mechanical wounding of plants triggers the release of a blend of reactive biogenic volatile organic compounds (BVOCs). During and after mowing and harvesting of managed grasslands, significant BVOC emissions have the potential to alter the physical and chemical properties of the atmosphere and lead to ozone and aerosol formation with consequences for regional air quality. We show that the amount and composition of BVOCs emitted per unit dry weight of plant material is comparable between laboratory enclosure measurements of artificially severed grassland plant species and in situ ecosystem-scale flux measurements above a temperate mountain grassland during and after periodic mowing and harvesting. The investigated grassland ecosystem emitted annually up to 130 mg carbon m?2 in response to cutting and drying, the largest part being consistently represented by methanol and a blend of green leaf volatiles (GLV). In addition, we report the plant species-specific emission of furfural, terpenoid-like compounds (e.g. camphor), and sesquiterpenes from cut plant material, which may be used as tracers for the presence of given plant species in the ecosystem. PMID:22409212

Brilli, Federico; Hörtnagl, Lukas; Bamberger, Ines; Schnitzhofer, Ralf; Ruuskanen, Taina M.; Hansel, Armin; Loreto, Francesco; Wohlfahrt, Georg

2013-01-01

123

Emission inventory of primary pollutants and chemical speciation in 2010 for the Yangtze River Delta region, China  

NASA Astrophysics Data System (ADS)

We developed a high-resolution emission inventory of primary air pollutants for Yangtze River Delta (YRD) region, which included Shanghai plus 24 cities in the provinces of Jiangsu and Zhejiang. The emissions of SO2, NOX, PM10, PM2.5, NMVOCs and NH3 in the year of 2010 were estimated as 2147 kt, 2776 kt, 1006 kt, 643 kt, 3822 kt and 1439 kt, respectively. Power plants are the largest emission sources for SO2 and NOX, which contributes 44.1% and 37.3% of total SO2 and NOX emissions. Emissions from industrial process accounted for 26.9%, 28.9% and 33.7% of the total PM10, PM2.5 and NMVOCs respectively. Besides, 37.3% of NMVOCs emissions were contributed by solvent use. Livestock and fertilizer application contribute over 90% of NH3 emissions. High emission densities are visible in Shanghai and the area around Tai Lake. This emission inventory includes the speciation of PM2.5 for the YRD region for the first time, which is important to source apportionment and secondary-pollution analysis. In 2010, emissions of three major PM2.5 species, namely OC, EC and sulfate, are 136.9 kt, 75.0 kt and 76.2 kt, respectively. Aromatics and alkanes are the main NMVOC species, accounting for 30.4% and 20.3% of total VOCs. Non-road transportation and biomass burning were main uncertain sources because of a lack of proper activity and emission factor data. Compared with other pollutants, NMVOCs and NH3 have higher uncertainty. From 2000 to 2010, emissions of all pollutants have changed significantly, suggesting that the newly updated and high-resolution emission inventory will be useful for the identification of air pollution sources in YRD.

Fu, Xiao; Wang, Shuxiao; Zhao, Bin; Xing, Jia; Cheng, Zhen; Liu, Huan; Hao, Jiming

2013-05-01

124

Toxic Volatile Organic Compounds in Environmental Tobacco Smoke:Emission Factors for Modeling Exposures of California Populations  

SciTech Connect

The primary objective of this study was to measure emission factors for selected toxic air in environmental tobacco smoke (ETS) using a room-sized environmental chamber. The emissions of 23 volatile organic compounds (VOCs), including 1,3-butadiene, three aldehydes and two vapor-phase N-nitrosarnines were determined for six commercial brands of cigarettes and reference cigarette 1R4F. The commercial brands were selected to represent 62.5% of the cigarettes smoked in California. For each brand, three cigarettes were machine smoked in the chamber. The experiments were conducted over four hours to investigate the effects of aging. Emission factors of the target compounds were also determined for sidestream smoke (SS). For almost all target compounds, the ETS emission factors were significantly higher than the corresponding SS values probably due to less favorable combustion conditions and wall losses in the SS apparatus. Where valid comparisons could be made, the ETS emission factors were generally in good agreement with the literature. Therefore, the ETS emission factors, rather than the SS values, are recommended for use in models to estimate population exposures from this source. The variabilities in the emission factors (pgkigarette) of the selected toxic air contaminants among brands, expressed as coefficients of variation, were 16 to 29%. Therefore, emissions among brands were generally similar. Differences among brands were related to the smoked lengths of the cigarettes and the masses of consumed tobacco. Mentholation and whether a cigarette was classified as light or regular did not significantly affect emissions. Aging was determined not to be a significant factor for the target compounds. There were, however, deposition losses of the less volatile compounds to chamber surfaces.

Daisey, J.M.; Mahanama, K.R.R.; Hodgson, A.T.

1994-10-01

125

Field Derived Emission Factors For Formaldehyde and other Volatile Organic Compounds in FEMA Temporary Housing Units  

SciTech Connect

Sixteen previously occupied temporary housing units (THUs) were studied to assess emissions of volatile organic compounds. The whole trailer emission factors wereevaluated for 36 VOCs including formaldehyde. Indoor sampling was carried out in the THUs located in Purvis staging yard in Mississippi, USA. Indoor temperature andrelative humidity (RH) were also measured in all the trailers during sampling. Indoor temperatures were varied (increased or decreased) in a selection of THUs using theheating, ventilation and air conditioning (HVAC) systems. Indoor temperatures during sampling ranged from 14o C to 33o C, and relative humidity (RH) varied between 35percentand 74percent. Ventilation rates were increased in some trailers using bathroom fans and vents during some of the sampling events. Ventilation rates measured during some aselection of sampling events varied from 0.14 to 4.3 h-1. Steady state indoor formaldehyde concentrations ranged from 10 mu g-m-3 to 1000 mu g-m-3. The formaldehyde concentrations in the trailers were of toxicological significance. The effects of temperature, humidity and ventilation rates were also studied. A linearregression model was built using log of percentage relative humidity, inverse of temperature (in K-1), and inverse log ACH as continuous independent variables, trailermanufacturer as a categorical independent variable, and log of the chemical emission factors as the dependent variable. The coefficients of inverse temperature, log relativehumidity, log inverse ACH with log emission factor were found to be statistically significant for all the samples at the 95percent confidence level. The regression model wasfound to explain about 84percent of the variation in the dependent variable. Most VOC concentrations measured indoors in the Purvis THUs were mostly found to be belowvalues reported in earlier studies by Maddalena et al.,1,2 Hodgson et al.,3 and Hippelein4. Emissions of TMPB-DIB (a plasticizer found in vinyl products) were found to be higher than values reported in comparable housing by Hodgson et al.,3. Emissions of phenol were also found to be slightly higher than values reported in earlier studies1,2,3. This study can assist in retrospective formaldehyde exposure assessments of THUs where estimates of the occupants indoor formaldehyde exposures are needed.

Parthasarathy, Srinandini; Maddalena, Randy L.; Russell, Marion L.; Apte, Michael G.

2010-10-01

126

The emission of volatile compounds during the aerobic and the combined anaerobic/aerobic composting of biowaste  

NASA Astrophysics Data System (ADS)

Two different biowaste composting techniques were compared with regard to their overall emission of volatile compounds during the active composting period. In the aerobic composting process, the biowaste was aerated during a 12-week period, while the combined anaerobic/aerobic composting process consisted of a sequence of a 3-week anaerobic digestion (phase I) and a 2-week aeration period (phase II). While the emission of volatiles during phase I of the combined anaerobic/aerobic composting process was measured in a full-scale composting plant, the aerobic stages of both composting techniques were performed in pilot-scale composting bins. Similar groups of volatile compounds were analysed in the biogas and the aerobic composting waste gases, being alcohols, carbonyl compounds, terpenes, esters, sulphur compounds and ethers. Predominance of alcohols (38% wt/wt of the cumulative emission) was observed in the exhaust air of the aerobic composting process, while predominance of terpenes (87%) and ammonia (93%) was observed in phases I and II of the combined anaerobic/aerobic composting process, respectively. In the aerobic composting process, 2-propanol, ethanol, acetone, limonene and ethyl acetate made up about 82% of the total volatile organic compounds (VOC)-emission. Next to this, the gas analysis during the aerobic composting process revealed a strong difference in emission profile as a function of time between different groups of volatiles. The total emission of VOC, NH 3 and H 2S during the aerobic composting process was 742 g ton -1 biowaste, while the total emission during phases I and II of the combined anaerobic/aerobic composting process was 236 and 44 g ton -1 biowaste, respectively. Taking into consideration the 99% removal efficiency of volatiles upon combustion of the biogas of phase I in the electricity generator, the combined anaerobic/aerobic composting process can be considered as an attractive alternative for aerobic biowaste composting because of its 17 times lower overall emission of the volatiles mentioned.

Smet, Erik; Van Langenhove, Herman; De Bo, Inge

127

Impacts of uncertainty in AVOC emissions on the summer RO x budget and ozone production rate in the three most rapidly-developing economic growth regions of China  

NASA Astrophysics Data System (ADS)

High levels of uncertainty in non-methane volatile organic compound (NMVOC) emissions in China could lead to significant variation in the budget of the sum of hydroxyl (OH) and peroxy (HO2, RO2) radicals (RO x = OH + HO2 + RO2) and the ozone production rate [P(O3)], but few studies have investigated this possibility, particularly with three-dimensional air quality models. We added diagnostic variables into the WRF-Chem model to assess the impact of the uncertainty in anthropogenic NMVOC (AVOC) emissions on the RO x budget and P(O3) in the Beijing-Tianjin-Hebei region, Yangtze River Delta, and Pearl River Delta of China. The WRF-Chem simulations were compared with satellite and ground observations, and previous observation-based model studies. Results indicated that 68% increases (decreases) in AVOC emissions produced 4%-280% increases (2%-80% decreases) in the concentrations of OH, HO2, and RO2 in the three regions, and resulted in 35%-48% enhancements (26%-39% reductions) in the primary RO x production and ˜ 65% decreases (68%-73% increases) of the P(O3) in Beijing, Shanghai, and Guangzhou. For the three cities, the two largest contributors to the RO x production rate were the reaction of O1D + H2O and photolysis of HCHO, ALD2, and others; the reaction of OH + NO2 (71%-85%) was the major RO x sink; and the major contributor to P(O3) was the reaction of HO2 + NO (˜ 65%). Our results showed that AVOC emissions in 2006 from Zhang et al. (2009) have been underestimated by ˜ 68% in suburban areas and by > 68% in urban areas, implying that daily and hourly concentrations of secondary organic aerosols and inorganic aerosols could be substantially underestimated, and cloud condensation nuclei could be underestimated, whereas local and regional radiation was overestimated.

Wang, Feng; An, Junling; Li, Ying; Tang, Yujia; Lin, Jian; Qu, Yu; Chen, Yong; Zhang, Bing; Zhai, Jing

2014-11-01

128

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

SciTech Connect

A study to measure indoor concentrations and emission rates of volatile organic compounds (VOCs), including formaldehyde, was conducted in a new, unoccupied manufactured house installed at the National Institute of Standards and Technology (NIST) campus. The house was instrumented to continuously monitor indoor temperature and relative humidity, heating and air conditioning system operation, and outdoor weather. It also was equipped with an automated tracer gas injection and detection system to estimate air change rates every 2 h. Another automated system measured indoor concentrations of total VOCs with a flame ionization detector every 30 min. Active samples for the analysis of VOCs and aldehydes were collected indoors and outdoors on 12 occasions from August 2002 through September 2003. Individual VOCs were quantified by thermal desorption to a gas chromatograph with a mass spectrometer detector (GC/MS). Formaldehyde and acetaldehyde were quantified by high performance liquid chromatography (HPLC). Weather conditions changed substantially across the twelve active sampling periods. Outdoor temperatures ranged from 7 C to 36 C. House air change rates ranged from 0.26 h{sup -1} to 0.60 h{sup -1}. Indoor temperature was relatively constant at 20 C to 24 C for all but one sampling event. Indoor relative humidity (RH) ranged from 21% to 70%. The predominant and persistent indoor VOCs included aldehydes (e.g., formaldehyde, acetaldehyde, pentanal, hexanal and nonanal) and terpene hydrocarbons (e.g., a-pinene, 3-carene and d-limonene), which are characteristic of wood product emissions. Other compounds of interest included phenol, naphthalene, and other aromatic hydrocarbons. VOC concentrations were generally typical of results reported for other new houses. Measurements of total VOCs were used to evaluate short-term changes in indoor VOC concentrations. Most of the VOCs probably derived from indoor sources. However, the wall cavity was an apparent source of acetaldehyde, toluene and xylenes and the belly space was a source of 2-butanone, lower volatility aldehydes and aromatic hydrocarbons. Indoor minus outdoor VOC concentrations varied with time. Adjusted formaldehyde concentrations exhibited the most temporal variability with concentrations ranging from 25 {micro}g m{sup -3} to 128 {micro}g m{sup -3} and the lowest concentrations occurring in winter months when indoor RH was low. A model describing the emissions of formaldehyde from urea-formaldehyde wood products as a function of temperature, RH and concentration reasonably predicted the temporal variation of formaldehyde emissions in the house. Whole-house emissions of other VOCs generally declined over the first three months and then remained relatively constant over a several month period. However, their emissions were generally lowest during the winter months. Also, an apparent association between TVOC emissions and outdoor temperature was observed on a one-week time scale.

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

2004-09-01

129

Volatile organic compound emissions from municipal solid waste disposal sites: a case study of Mumbai, India.  

PubMed

Improper solid waste management leads to aesthetic and environmental problems. Emission ofvolatile organic compounds (VOCs) is one of the problems from uncontrolled dumpsite. VOCs are well known to be hazardous to human health and many of them are known or potential carcinogens. They also contribute to ozone formation at ground level and climate change as well. The qualitative and quantitative analysis of VOCs emitting from two municipal waste (MSW) disposal sites in Mumbai, India, namely Deonar and Malad, are presented in this paper. Air at dumpsites was sampled and analyzed on gas chromatography-mass spectrometry (GC-MS) in accordance with U.S. Environmental Protection Agency (EPA) TO-17 compendium method for analysis of toxic compounds. As many as 64 VOCs were qualitatively identified, among which 13 are listed under hazardous air pollutants (HAPs). Study of environmental distribution of a few major VOCs indicates that although air is the principal compartment of residence, they also get considerably partitioned in soil and vegetation. The CO2 equivalent of target VOCs from the landfills in Malad and Deonar shows that the total yearly emissions are 7.89E+03 and 8.08E+02 kg, respectively. The total per hour ozone production from major VOCs was found to be 5.34E-01 ppb in Deonar and 9.55E-02 ppb in Malad. The total carcinogenic risk for the workers in the dumpsite considering all target HAPs are calculated to be 275 persons in 1 million in Deonar and 139 persons in 1 million in Malad. PMID:22616282

Majumdar, Dipanjali; Srivastava, Anjali

2012-04-01

130

Tracing CO2 fluxes and plant volatile organic compound emissions by stable isotopes  

NASA Astrophysics Data System (ADS)

Plant metabolic processes exert a large influence on global climate and air quality through the emission of the greenhouse gas CO2 and volatile organic compounds (VOCs). Despite the enormous importance, processes controlling plant carbon allocation into primary and secondary metabolism, such as respiratory CO2 emission and VOC synthesis, remains unclear. The vegetation exerts a large isotopic imprint on the atmosphere through both, photosynthetic carbon isotope discrimination and fractionation during respiratory CO2 release (?13Cres). While the former is well understood, many processes driving carbon isotope fractionation during respiration are unknown1. There are striking differences in variations of ?13Cres between plant functional groups, which have been proposed to be related to carbon partitioning in the metabolic branching points of the respiratory pathways and secondary metabolism, which are linked via a number of interfaces including the central metabolite pyruvate2. Notably, it is a known substrate in a large array of secondary pathways leading to the biosynthesis of many volatile organic compounds (VOCs), such as volatile isoprenoids, oxygenated VOCs, aromatics, fatty acid oxidation products, which can be emitted by plants. Here we investigate if carbon isotope fractionation in light and dark respired CO2 is associated with VOC emissions in the atmosphere. Specifically, we hypothesize that a high carbon flux through the pyruvate into various VOC synthesis pathways is associated with a pronounced 13C-enrichment of respired CO2 above the putative substrate, as it involves the decarboxylation of the 13C-enriched C-1 from pyruvate. Based on simultaneous real-time measurements of stable carbon isotope composition of branch respired CO2 (CRDS) and VOC fluxes (PTR-MS) we traced carbon flow into these pathways by pyruvate positional labeling. We demonstrated that in a Mediterranean shrub the 13C-enriched C-1 from pyruvate is released in substantial amounts as CO2 in the light. Simultaneously, naturally 13C depleted C-2 and C-3 carbon atoms of the acetyl-moiety are emitted as a variety of VOCs. Moreover, during light-dark transitions leaf emission bursts of the oxygenated metabolite acetaldehyde were observed as part of the PDH bypass pathway in the cytosol2. This may be a new piece of evidence for the origin of 13C-enriched ?13CO2 which is released during Light-Enhanced Dark Respiration (LEDR). Our study provides the first evidence that the isotopic signature of respired CO2 is closely linked to carbon partitioning between anabolic and catabolic pathways and plants strategies of carbon investment into secondary compound synthesis. Werner C. & Gessler A. (2011) Diel variations in the carbon isotope composition of respired CO2 and associated carbon sources: a review of dynamics and mechanisms. Biogeosciences 8, 2437-2459 Jardine K, Wegener F, Abrell L, vonHaren J, Werner C (2014) Phytogenic biosynthesis and emission of methyl acetate. PCE 37, 414-424.

Werner, Christiane; Wegener, Frederik; Jardine, Kolby

2014-05-01

131

Emission ratios of anthropogenic volatile organic compounds in northern mid-latitude megacities: Observations versus emission inventories in Los Angeles and Paris  

NASA Astrophysics Data System (ADS)

Ground-based and airborne volatile organic compound (VOC) measurements in Los Angeles, California, and Paris, France, during the Research at the Nexus of Air Quality and Climate Change (CalNex) and Megacities: Emissions, Urban, Regional and Global Atmospheric Pollution and Climate Effects, and Integrated Tools for Assessment and Mitigation (MEGAPOLI) campaigns, respectively, are used to examine the spatial variability of the composition of anthropogenic VOC urban emissions and to evaluate regional emission inventories. Two independent methods that take into account the effect of chemistry were used to determine the emission ratios of anthropogenic VOCs (including anthropogenic isoprene and oxygenated VOCs) over carbon monoxide (CO) and acetylene. Emission ratios from both methods agree within ±20%, showing the reliability of our approach. Emission ratios for alkenes, alkanes, and benzene are fairly similar between Los Angeles and Paris, whereas the emission ratios for C7-C9 aromatics in Paris are higher than in Los Angeles and other French and European Union urban areas by a factor of 2-3. The results suggest that the emissions of gasoline-powered vehicles still dominate the hydrocarbon distribution in northern mid-latitude urban areas, which disagrees with emission inventories. However, regional characteristics like the gasoline composition could affect the composition of hydrocarbon emissions. The observed emission ratios show large discrepancies by a factor of 2-4 (alkanes and oxygenated VOC) with the ones derived from four reference emission databases. A bias in CO emissions was also evident for both megacities. Nevertheless, the difference between measurements and inventory in terms of the overall OH reactivity is, in general, lower than 40%, and the potential to form secondary organic aerosols (SOA) agrees within 30% when considering volatile organic emissions as the main SOA precursors.

Borbon, Agnes; Gilman, J. B.; Kuster, W. C.; Grand, N.; Chevaillier, S.; Colomb, A.; Dolgorouky, C.; Gros, V.; Lopez, M.; Sarda-Esteve, R.; Holloway, J.; Stutz, J.; Petetin, H.; McKeen, S.; Beekmann, M.; Warneke, C.; Parrish, D. D.; Gouw, J. A.

2013-02-01

132

Microbial volatile organic compound emissions from Stachybotrys chartarum growing on gypsum wallboard and ceiling tile  

PubMed Central

Background Stachybotrys chartarum is a filamentous mold frequently identified among the mycobiota of water-damaged building materials. Growth of S. chartarum on suitable substrates and under favorable environmental conditions leads to the production of secondary metabolites such as mycotoxins and microbial volatile organic compounds (MVOCs). The aim of this study was to characterize MVOC emission profiles of seven toxigenic strains of S. chartarum, isolated from water-damaged buildings, in order to identify unique MVOCs generated during growth on gypsum wallboard and ceiling tile coupons. Inoculated coupons were incubated and monitored for emissions and growth using a closed glass environmental growth chamber maintained at a constant room temperature. Gas samples were collected from the headspace for three to four weeks using Tenax TA tubes. Results Most of the MVOCs identified were alcohols, ketones, ethers and esters. The data showed that anisole (methoxybenzene) was emitted from all of the S. chartarum strains tested on both types of substrates. Maximum anisole concentration was detected after seven days of incubation. Conclusions MVOCs are suitable markers for fungal identification because they easily diffuse through weak barriers like wallpaper, and could be used for early detection of mold growth in hidden cavities. This study identifies the production of anisole by seven toxigenic strains of Stachybotrys chartarum within a period of one week of growth on gypsum wallboard and ceiling tiles. These data could provide useful information for the future construction of a robust MVOC library for the early detection of this mold. PMID:24308451

2013-01-01

133

Volatile organic compound emissions from Miscanthus and short rotation coppice willow bioenergy crops  

NASA Astrophysics Data System (ADS)

Miscanthus × giganteus and short rotation coppice (SRC) willow (Salix spp.) are increasingly important bioenergy crops. Above-canopy fluxes and mixing ratios of volatile organic compounds (VOCs) were measured in summer for the two crops at a site near Lincoln, UK, by proton transfer reaction mass spectrometry (PTR-MS) and virtual disjunct eddy covariance. The isoprene emission rate above willow peaked around midday at ?1 mg m-2 h-1, equivalent to 20 ?g gdw-1 h-1 normalised to 30 °C and 1000 ?mol m-2 s-1 PAR, much greater than for conventional arable crops. Average midday peak isoprene mixing ratio was ?1.4 ppbv. Acetone and acetic acid also showed small positive daytime fluxes. No measurable fluxes of VOCs were detected above the Miscanthus canopy. Differing isoprene emission rates between different bioenergy crops, and the crops or vegetation cover they may replace, means the impact on regional air quality should be taken into consideration in bioenergy crop selection.

Copeland, Nichola; Cape, J. Neil; Heal, Mathew R.

2012-12-01

134

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

PubMed

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

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

2013-12-01

135

Emission of volatile organic compounds from composting of different solid wastes: abatement by biofiltration.  

PubMed

Emission of volatile organic compounds (VOCs) produced during composting of different organic wastes (source-selected organic fraction of municipal solid wastes (OFMSW), raw sludge (RS) and anaerobically digested wastewater sludge (ADS) and animal by-products (AP)) and its subsequent biofiltration have been studied. Composting was performed in a laboratory scale composting plant (30l) and the exhaust gases generated were treated by means of a compost biofilter. VOCs concentration in the composting exhaust gases for each composting process ranged from 50 to 695 mg C m-3 for OFMSW (5:1), from 13 to 190 mg C m-3 for OFMSW (1:1), from 200 to 965 mg C m-3 for RS, from 43 to 2900 mg C m-3 for ADS and from 50 to 465 mg C m-3 for AP. VOCs emissions were higher during the beginning of the composting process and were not generally related to the biological activity of the process. These emissions corresponded to an average loading rate applied to the biofilter from 2.56 to 29.7 g C m-3 biofilter h-1. VOCs concentration in the exhaust gas from the biofilter ranged from 55 to 295 mg C m-3 for OFMSW (5:1), from 12 to 145 mg C m-3 for OFMSW (1:1), from 55 to 270 mg C m-3 for RS, from 42 to 855 mg C m-3 for ADS and from 55 to 315 mg C m-3 for AP. Removal efficiencies up to 97% were achieved although they were highly dependent of the composted waste. An important observation was that the compost biofilter emitted VOCs with an estimated concentration of 50 mg C m-3. PMID:16219417

Pagans, Estela; Font, Xavier; Sánchez, Antoni

2006-04-17

136

Detection of organic compound signatures in infra-red, limb emission spectra observed by the MIPAS-B2 instrument  

Microsoft Academic Search

Organic compounds play a central role in troposphere chemistry and increasingly are a viable target for remote sensing observations. In this paper, infra-red spectral features of three organic compounds are investigated in thermal emission spectra recorded by a balloon-borne instrument, MIPAS-B2, operating at high spectral resolution. It is demonstrated, for the first time, that PAN and acetone can be detected

J. J. Remedios; G. Allen; A. M. Waterfall; H. Oelhaf; A. Kleinert

2006-01-01

137

Observations of nonmethane organic compounds during ARCTAS - Part 1: Biomass burning emissions and plume enhancements  

NASA Astrophysics Data System (ADS)

Mixing ratios of a large number of nonmethane organic compounds (NMOCs) were observed by the Trace Organic Gas Analyzer (TOGA) on board the NASA DC-8 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaign. Many of these NMOCs were observed concurrently by one or both of two other NMOC measurement techniques on board the DC-8: proton-transfer-reaction mass spectrometry (PTR-MS) and whole air canister sampling (WAS). A comparison of these measurements to the data from TOGA indicates good agreement for the majority of co-measured NMOCs. The ARCTAS study, which included both spring and summer deployments, provided opportunities to sample a large number of biomass burning (BB) plumes with origins in Asia, California and central Canada, ranging from very recent emissions to plumes aged one week or more. For this analysis, BB smoke interceptions were grouped by flight, source region and, in some cases, time of day, generating 40 identified BB plumes for analysis. Normalized excess mixing ratios (NEMRs) to CO were determined for each of the 40 plumes for up to 19 different NMOCs or NMOC groups. Although the majority of observed NEMRs for individual NMOCs or NMOC groups were in agreement with previously-reported values, the observed NEMRs to CO for ethanol, a rarely quantified gas-phase trace gas, ranged from values similar to those previously reported, to up to an order of magnitude greater. Notably, though variable between plumes, observed NEMRs of individual light alkanes are highly correlated within BB emissions, independent of estimated plume ages. BB emissions of oxygenated NMOC were also found to be often well-correlated. Using the NCAR Master Mechanism chemical box model initialized with concentrations based on two observed scenarios, fresh Canadian BB and fresh Californian BB, decreases are predicted for the low molecular weight carbonyls (i.e. formaldehyde, acetaldehyde, acetone and methyl ethyl ketone, MEK) and alcohols (i.e. methanol and ethanol) as the plumes evolve in time, i.e. the production of these compounds is less than the chemical loss. Comparisons of the modeled NEMRs to the observed NEMRs from BB plumes estimated to be three days in age or less indicate overall good agreement.

Hornbrook, R. S.; Blake, D. R.; Diskin, G. S.; Fried, A.; Fuelberg, H. E.; Meinardi, S.; Mikoviny, T.; Richter, D.; Sachse, G. W.; Vay, S. A.; Walega, J.; Weibring, P.; Weinheimer, A. J.; Wiedinmyer, C.; Wisthaler, A.; Hills, A.; Riemer, D. D.; Apel, E. C.

2011-11-01

138

Emissions of isoprenoids and oxygenated biogenic volatile organic compounds from a New England mixed forest  

NASA Astrophysics Data System (ADS)

Fluxes of biogenic volatile organic compounds, including isoprene, monoterpenes, and oxygenated VOCs measured above a mixed forest canopy in central Massachusetts during the 2005 and 2007 growing seasons are reported. Mixing ratios were measured using proton transfer reaction mass spectrometry (PTR-MS) and fluxes computed by the disjunct eddy covariance technique. Isoprene was by far the predominant BVOC emitted at this site, with summer mid-day average fluxes of 5.3 and 4.4 mg m-2 hr-1 in 2005 and 2007, respectively. In comparison, mid-day average fluxes of monoterpenes were 0.21 and 0.15 mg m-2 hr-1 in each of these years. On short times scales (days), the diel pattern in emission rate compared well with a standard emission algorithm for isoprene. The general shape of the seasonal cycle and the observed decrease in isoprene emission rate in early September was, however, not well captured by the model. Monoterpene emission rates exhibited dependence on light as well as temperature, as determined from the improved fit to the observations obtained by including a light-dependent term in the model. The mid-day average flux of methanol from the canopy was 0.14 mg m-2 hr-1 in 2005 and 0.19 mg m-2 hr-1 in 2007, but the maximum flux was observed in spring (29 May 2007), when the flux reached 1.0 mg m-2 hr-1. This observation is consistent with enhanced methanol production during leaf expansion. Summer mid-day fluxes of acetone were 0.15 mg m-2 hr-1 during a short period in 2005, but only 0.03 mg m-2 h-1 averaged over 2007. Episodes of negative fluxes of oxygenated VOCs, particularly acetone, were observed periodically, especially in 2007. Thus, deposition within the canopy could help explain the low season-averaged flux of acetone in 2007. Fluxes of species of biogenic origin at mass-to-charge (m/z) ratios of 73 (0.05 mg m-2 hr-1 in 2005; 0.03 mg m-2 hr-1 in 2007) and 153 (5 ?g m-2 hr-1 in 2007), possibly corresponding to methyl ethyl ketone and an oxygenated terpene or methyl salicylate, respectively, were also observed.

McKinney, K. A.; Lee, B. H.; Vasta, A.; Pho, T. V.; Munger, J. W.

2011-05-01

139

Compound  

NASA Astrophysics Data System (ADS)

We have prepared Ce-doped polycrystalline AgSbTe2.01 compounds from high-purity elements by a melt-quench technique followed by spark plasma sintering, and their thermoelectric transport properties have been investigated in the temperature range of 300 K to 625 K. The actual concentration of Ce was much less than the initial composition, but roughly proportional to it. Small additions of Ce shifted the composition of the homogeneity range from the nearly ideal atomic ratio Ag:Sb:Te = 0.98:1.02:2.01 toward Sb rich (Ag poor), and led to the reemergence of Ag2Te impurity in AgSbTe2 compound. The Ce-doped samples possessed lower electrical conductivity compared with the undoped AgSbTe2.01 compound at room temperature, but the carrier mobility and effective mass were essentially constant, indicating intact band structure near the covalent band maximum upon Ce substitution for Sb. Due to the decrease of lattice vibration anharmonicity resulting from Ce substitution for Sb, the lattice conductivity of the Ce-doped samples was about 0.1 W m-1 K-1 higher than that of the AgSbTe2.01 sample, and the magnitude spanned the range from 0.30 W m-1 K-1 to 0.55 W m-1 K-1. A ZT of 1.20 was achieved at about 615 K for the AgSb0.99Ce0.01Te2.01 sample.

Du, B.; Li, H.; Tang, X.

2014-06-01

140

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...

141

AN IMPROVED MODEL FOR ESTIMATING EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM FORESTS IN THE EASTERN UNITED STATES (Journal)  

EPA Science Inventory

Regional estimates of biogenic volatile organic compound (BVOC) emissions are important inputs for models of atmospheric chemistry and carbon budgets. Since forests are the primary emitters of BVOCs, it is important to develop reliable estimates of their areal coverage and BVOC e...

142

An Evaluation of Hazardous Air Pollutants and Volatile Organic Compound Emissions from Tank Barges in Memphis, TN  

EPA Science Inventory

Many urban centers have population centers near river ports, which may be affected by volatile organic compound (VOC) and hazardous air pollutant (HAP) emissions from tank barge traffic. This study will examine Memphis, Tennessee and West Memphis, Arkansas. Both cities (located ...

143

CAPILLARY GAS CHROMATOGRAPHY-ATOMIC EMISSION DETECTION METHOD FOR THE DETERMINATION OF PENTYLATED ORGANOTIN COMPOUNDS: INTERLABORATORY STUDY  

EPA Science Inventory

A capillary gas chromatography-atomic emission detection (GC-AED) method was developed for the U. S. Environmental Protection Agency's Environmental Monitoring Systems Laboratory in Las Vegas, NV, for determination of selected organotin compounds. Here we report on an interlabora...

144

BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS (BVOCS) I. IDENTIFICATIONS FROM THREE CONTINENTAL SITES IN THE U.S.  

EPA Science Inventory

Vegetation composition and biomass were surveyed for three specific sites in Atlanta, GA; near Rhinelander, WI; and near Hayden, CO. At each research site, emissions of biogenic volatile organic compounds (BVOCs) from the dominant vegetation species were sampled by enclosing bran...

145

Influence of suspended particles on indoor semi-volatile organic compounds emission  

NASA Astrophysics Data System (ADS)

Semi-volatile organic compounds (SVOCs) have been attracting more and more attentions to many researchers in these years. Because SVOCs have a strong tendency for adsorption to suspended particles, we take the effect of suspended particles into account to study the transport mechanism of SVOCs in the air. We establish a mathematical model to describe the transport mechanism of SVOCs, and study the transport processes of both gas- and particle-phase di-2-ethylhexyl phthalate (DEHP) in Field and Laboratory Emission Cells (FLECs). The predictions by the proposed model not only fit well with the experimental data of previous studies, but also show that the gas-phase DEHP concentration increases rapidly in the first few seconds and increases slowly during the following 200 days due to different transport mechanisms in the two periods. Meanwhile, when the particle radiuses are of the order of micron and the air changes per hour (ACH) is large enough, the characteristic time for DEHP getting gas/particle equilibrium is much longer than the residence time of a particle in the flow field, and thus there is no significant influence of suspended particles on the total concentration of DEHP in the air. Oppositely, the influence of particles on DEHP emission will be enhanced for a cycling air flow system with a small ACH, where increasing ACH will reduce the concentrations of particle-phase SVOCs. Besides, if the particle radiuses are of the order of nanometer, decreasing the particle radiuses will shorter the characteristic time for DEHP getting gas/particle equilibrium, and finally increase the particle-phase concentration of DEHP.

Hu, Kang; Chen, Qun; Hao, Jun-Hong

2013-11-01

146

Effects of gasoline aromatic content on emissions of volatile organic compounds and aldehydes from a four-stroke motorcycle.  

PubMed

A new four-stroke carburettor motorcycle engine without any engine adjustments was used to study the impact of fuel aromatic content on the exhaust emissions of organic air pollutants (volatile organic compounds and carbonyls). Three levels of aromatic content, i.e. 15, 25, and 50% (vol.) aromatics mixed with gasoline were tested. The emissions of aromatic fuel were compared with those of commercial unleaded gasoline. The results indicated that the A 15 (15 vol% aromatics in gasoline) fuel exhibited the greatest total organic emission improvement among these three aromatic fuels as compared with commercial gasoline, reaching 59%. The highest emission factors of alkanes, alkenes, and carbonyl groups appeared in the reference fuel (RF) among all of the test fuels. A 15 showed the highest emission reduction in alkanes (73%), aromatics (36%), and carbonyls (28%), as compared to those of the RF. The highest emission reduction ofalkenes was observed when using A25 as fuel. A reduction in fuel aromatic content from 50 to 25 and 15 vol% in gasoline decreased benzene and toluene emissions, but increased the aldehyde emissions. In general, the results showed that the highest emission reductions for the most of measured organic pollutants appeared when using A 15 as the fuel. PMID:24527614

Yao, Yung-Chen; Tsai, Jiun-Horng

2013-01-01

147

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

148

A new European plant-specific emission inventory of biogenic volatile organic compounds for use in atmospheric transport models  

NASA Astrophysics Data System (ADS)

We present a new European plant-specific emission inventory for isoprene, monoterpenes, sesquiterpenes and other VOC (OVOC), with a spatial resolution of 10 km, for implementation in atmospheric transport models. The inventory incorporates new data on emission factors at standard conditions for tree and crop species that became available in the last years and more accurate data on foliar biomass densities coming from several new litterfall databases. In contrast to previous emission inventories, a bioclimatic correction factor was introduced to correct the foliar biomass densities for the different plant growth conditions that can be found in Pan-Europe. The 2004-2005 averaged annual total biogenic volatile organic compound (BVOC) emissions for the Pan-European domain are estimated to be about 15 Tg with a large contribution from the OVOC class of about 6 Tg and from monoterpenes of about 5 Tg. Annual isoprene emissions are found to be about 3 Tg, insensitive to the chosen emission algorithm. For the first time crop-specific land use information and standard emission factors were employed. Contrary to former European inventories, emissions of monoterpenes and OVOC were found to originate to a large extent from agriculture. However, monoterpene standard emission factors for crops are highly uncertain and probably positively biased by measurement artifacts. Further experiments on crop emissions should be carried out to check the validity of the high emission factors for monoterpenes and OVOC. In view of future intensified use of agricultural crops as biofuels, emissions of OVOC and monoterpenes from agriculture need to be evaluated in the field.

Karl, M.; Guenther, A.; Köble, R.; Seufert, G.

2008-12-01

149

Positron emission tomography with Pittsburgh compound B in diagnosis of early stage Alzheimer's disease.  

PubMed

In order to evaluate the role of positron emission tomography (PET) with N-methyl-[(11)C]-2-(4'-methylaminophenyl)-6-hydroxybenzothiazole, also known as Pittsburgh compound B (PIB), in the early diagnosis of Alzheimer's disease (AD). Clinical data were collected, and PIB PET cerebral imaging was performed in patients with AD (n = 6), mild cognitive impairment (MCI) (n = 7), and elderly, mentally normal controls (NCs) (n = 7). PET images of the subjects were then analyzed. Visual analysis showed that the radioactivity clearance rate in AD patients was significantly different from that found in the NC group. Furthermore, the radioactivity clearance rate 45 min after PIB injection was significantly lower than the NC group. Images from the MCI group presented heterogeneous results, overlapping with those from both the AD and NC groups. Statistical analysis showed that the radioactivity clearance rate during 5-45 min post-injection was significantly lower in the AD group (41-77%) than the control group (75-81%) (P > 0.05) and the MCI group (59-77%). The radioactivity clearance rate in the bilateral parietal lobes, frontal, temporal, and right occipital lobes, and the bilateral corpora striata in MCI group were lower than that in control group (P < 0.05). PIB PET brain imaging can differentiate early AD patients from NCs and may have certain value in identifying patients progressing to MCI. PMID:20714824

Jia, Jianjun; Sun, Binbin; Guo, Zhe; Zhang, Jinming; Tian, Jiahe; Tang, Hongchuan; Wang, Luning

2011-01-01

150

Bacterial pathogen indicators regrowth and reduced sulphur compounds' emissions during storage of electro-dewatered biosolids.  

PubMed

Electro-dewatering (ED) increases biosolids dryness from 10-15 to 30-50%, which helps wastewater treatment facilities control disposal costs. Previous work showed that high temperatures due to Joule heating during ED inactivate total coliforms to meet USEPA Class A biosolids requirements. This allows biosolids land application if the requirements are still met after the storage period between production and application. In this study, we examined bacterial regrowth and odour emissions during the storage of ED biosolids. No regrowth of total coliforms was observed in ED biosolids over 7d under aerobic or anaerobic incubations. To mimic on-site contamination during storage or transport, ED samples were seeded with untreated sludge. Total coliform counts decreased to detection limits after 4d in inoculated samples. Olfactometric analysis of ED biosolids odours showed that odour concentrations were lower compared to the untreated and heat-treated control biosolids. Furthermore, under anaerobic conditions, odorous reduced sulphur compounds (methanethiol, dimethyl sulphide and dimethyl disulphide) were produced by untreated and heat-treated biosolids, but were not detected in the headspaces above ED samples. The data demonstrate that ED provides advantages not only as a dewatering technique, but also for producing biosolids with lower microbial counts and odour levels. PMID:25065797

Navab-Daneshmand, Tala; Enayet, Samia; Gehr, Ronald; Frigon, Dominic

2014-10-01

151

Multiyear trends in volatile organic compounds in Los Angeles, California: Five decades of decreasing emissions  

NASA Astrophysics Data System (ADS)

Airborne measurements of volatile organic compounds (VOCs) were performed during CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change) in the Los Angeles (LA) basin in May-June 2010 and during ITCT2k2 (Intercontinental Transport and Chemical Transformation) in May 2002. While CO2 enhancements in the basin were similar between the two years, the ?CO/?CO2 ratio had decreased by about a factor of two. The ?VOC/?CO emission ratios stayed relatively constant between the two years. This indicates that, relative to CO2, VOCs in the LA basin also decreased by about a factor of two since 2002. These data are compared with the results from various previous field campaigns dating back as early as 1960 and from the extensive air quality monitoring system in the LA basin going back to 1980. The results show that the mixing ratios of VOCs and CO have decreased by almost two orders of magnitude during the past five decades at an average annual rate of about 7.5%. Exceptions to this trend are the small alkanes ethane and propane, which have decreased slower due to the use and production of natural gas. A comparison with trends in London, UK shows that, due to stricter regulations at the time, VOC mixing ratios in LA decreased earlier than in London, albeit at a slower rate, such that typical mixing ratios in both cities in 2008 were at about the same level.

Warneke, Carsten; de Gouw, Joost A.; Holloway, John S.; Peischl, Jeff; Ryerson, Thomas B.; Atlas, Elliot; Blake, Don; Trainer, Michael; Parrish, David D.

2012-09-01

152

Multiyear trends in volatile organic compounds in Los Angeles, California: Five decades of decreasing emissions  

NASA Astrophysics Data System (ADS)

Airborne measurements of volatile organic compounds (VOCs) were performed during CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change) in the Los Angeles (LA) basin in May-June 2010 and during ITCT2k2 (Intercontinental Transport and Chemical Transformation) in May 2002. While CO2 enhancements in the basin were similar between the two years, the ?CO/?CO2 ratio had decreased by about a factor of two. The ?VOC/?CO emission ratios stayed relatively constant between the two years. This indicates that, relative to CO2, VOCs in the LA basin also decreased by about a factor of two since 2002. These data are compared with the results from various previous field campaigns dating back as early as 1960 and from the extensive air quality monitoring system in the LA basin going back to 1980. The results show that the mixing ratios of VOCs and CO have decreased by almost two orders of magnitude during the past five decades at an average annual rate of about 7.5%. Exceptions to this trend are the small alkanes ethane and propane, which have decreased slower due to the use and production of natural gas. A comparison with trends in London, UK shows that, due to stricter regulations at the time, VOC mixing ratios in LA decreased earlier than in London, albeit at a slower rate, such that typical mixing ratios in both cities in 2008 were at about the same level.

Warneke, Carsten; Gouw, Joost A.; Holloway, John S.; Peischl, Jeff; Ryerson, Thomas B.; Atlas, Elliot; Blake, Don; Trainer, Michael; Parrish, David D.

2011-11-01

153

compounds  

NASA Astrophysics Data System (ADS)

Size is the key factor of nanostructured materials, since all the structural, transport, electrical, magnetic and other physical properties can be tuned by this factor of materials. Only the condition is to choose appropriate inexpensive scale-processing method for material synthesis which offers good control over the stoichiometry, morphology and particle size distribution. Present communication deals with the studies on the sol-gel grown Y0.95Ca0.05MnO3 (YCMO) nanostructured compounds for their size-induced tuning of dielectric behavior. Structural studies reveal the single phasic nature with improved crystallite size with sintering temperature. Dielectric constant (real and imaginary) is found to increase with temperature and crystallite size/sintering temperature. High dielectric loss has been observed in the present system. Size dependent activation energy ( E a), obtained from modulus measurement, showing the increase in E a with crystallite size. The variation in various dielectric parameters and E a has been discussed in the light of crystallite size, crystallite boundaries, oxygen vacancies and charge carrier hopping.

Shah, N. A.

2014-10-01

154

Contribution of the gasoline distribution cycle to volatile organic compound emissions in the metropolitan area of Mexico City.  

PubMed

Gasoline distribution in the metropolitan area of Mexico City (MAMC) represents an area of opportunity for the abatement of volatile organic compound (VOC) emissions. The gasoline distribution in this huge urban center encompasses several operations: (1) storage in bulk and distribution plants, (2) transportation to gasoline service stations, (3) unloading at service stations' underground tanks, and (4) gasoline dispensing. In this study, hydrocarbon (HC) emissions resulting from breathing losses in closed reservoirs, leakage, and spillage from the operations just listed were calculated using both field measurements and reported emission factors. The results show that the contribution of volatile HC emissions due to storage, distribution, and sales of gasoline is 6651 t/year, approximately 13 times higher than previously reported values. Tank truck transportation results in 53.9% of the gasoline emissions, and 31.5% of emissions are generated when loading the tank trucks. The high concentration of emissions in the gasoline transportation and loading operations by tank trucks has been ascribed to (1) highly frequent trips from distribution plant to gasoline stations, and vice versa, to cope with excessive gasoline sales per gasoline station; (2) low leakproofness of tank trucks; and (3) poor training of employees. In addition, the contribution to HC evaporative and exhaust emissions from the vehicles of the MAMC was also evaluated. PMID:12022693

Schifter, I; Magdaleno, M; Díaz, L; Krüger, B; León, J; Palmerín, M E; Casas, R; Melgarejo, A; López-Salinas, E

2002-05-01

155

A new European plant-specific emission inventory of biogenic volatile organic compounds for use in atmospheric transport models  

NASA Astrophysics Data System (ADS)

We present a new European plant-specific emission inventory for isoprene, monoterpenes, sesquiterpenes and oxygenated VOC (OVOC), on a spatial resolution of 0.089×0.089 degrees, for implementation in atmospheric transport models. The inventory incorporates more accurate data on foliar biomass densities from several litterfall databases that became available in the last years for the main tree species in Europe. A bioclimatic correction factor was introduced to correct the foliar biomass densities of trees and crops for the different plant growth conditions that can be found in Pan-Europe. Long-term seasonal variability of agriculture and forest emissions was taken into account by implementing a new growing season concept. The 2004-2005 averaged annual total biogenic volatile organic compound (BVOC) emissions for the Pan-European domain are estimated to be about 12 Tg with a large contribution from the OVOC class of about 4.5 Tg and from monoterpenes of about 4 Tg. Annual isoprene emissions are found to be about 3.5 Tg, insensitive to the chosen emission algorithm. Emissions of OVOC were found to originate to a large extent from agriculture. Further experiments on crop emissions should be carried out to check the validity of the applied standard emission factors. The new inventory aims at a fully transparent and verifiable aggregation of detailed land use information and at the inclusion of plant-specific emission data. Though plant-specific land use data is available with relatively high accuracy, a lack of experimental biomass densities and emission data on terpenes, sesquiterpenes and oxygenated VOC, in particular for agricultural plants, currently limits the setup of a highly accurate plant-specific emission inventory.

Karl, M.; Guenther, A.; Köble, R.; Leip, A.; Seufert, G.

2009-06-01

156

Assessment of control strategies for reducing volatile organic compound emissions from the polyvinyl chloride wallpaper production industry in Taiwan.  

PubMed

This study attempts to assess the effectiveness of control strategies for reducing volatile organic compound (VOC) emission from the polyvinyl chloride (PVC) wallpaper production industry. In Taiwan, methyl ethyl ketone, TOL, and cyclohexanone have comprised the major content of solvents, accounting for approximately 113,000 t/yr to avoid excessive viscosity of plasticizer dioctyl phthalate (DOP) and to increase facility in working. Emissions of these VOCs from solvents have caused serious odor and worse air quality problems. In this study, 80 stacks in five factories were tested to evaluate emission characteristics at each VOC source. After examining the VOC concentrations in the flue gases and contents, the VOC emission rate before treatment and from fugitive sources was 93,000 and 800 t/yr, respectively. In this study, the semiwet electrostatic precipitator is recommended for use as cost-effective control equipment. PMID:16739797

Chang, Chang-Tang; Chiou, Chyow-Shan

2006-05-01

157

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

PubMed

In recent years, electronic cigarettes have gained increasing popularity as alternatives to normal (tobacco-containing) cigarettes. In the present study, particles generated by e-cigarettes and normal cigarettes have been analyzed and the degree of exposure to different chemical agents and their emission rates were quantified. Despite the 10-fold decrease in the total exposure to particulate elements in e-cigarettes compared to normal cigarettes, specific metals (e.g. Ni and Ag) still displayed a higher emission rate from e-cigarettes. Further analysis indicated that the contribution of e-liquid to the emission of these metals is rather minimal, implying that they likely originate from other components of the e-cigarette device or other indoor sources. Organic species had lower emission rates during e-cigarette consumption compared to normal cigarettes. Of particular note was the non-detectable emission of polycyclic aromatic hydrocarbons (PAHs) from e-cigarettes, while substantial emission of these species was observed from normal cigarettes. Overall, with the exception of Ni, Zn, and Ag, the consumption of e-cigarettes resulted in a remarkable decrease in secondhand exposure to all metals and organic compounds. Implementing quality control protocols on the manufacture of e-cigarettes would further minimize the emission of metals from these devices and improve their safety and associated health effects. PMID:25180481

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

2014-10-01

158

Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results  

SciTech Connect

This report presents estimates of monthly sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program's Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment.

Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

1990-08-01

159

Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results  

SciTech Connect

This report presents estimates of monthly sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program`s Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment.

Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

1990-08-01

160

A Tree's Response to Herbivory: Quantification of Biogenic Volatile Organic Compound Emissions  

E-print Network

Distribution in Emissions from Bristlecone Pine Isoprene 3-Carene Limonene Linalool Other Terpenes 0 2 4 6 8 10 12 Other Linalool Limonene 3-Carene Mixing Ratio [ppbv] Monoterpene Emissions from Bristlecone Pine components of the pine emissions were isoprene, 3-carene, limonene, and linalool. � Exogenous methyl

Collins, Gary S.

161

Do volatile organic compound emissions of Tunisian cork oak populations originating from contrasting climatic conditions differ in their responses to summer drought?  

Microsoft Academic Search

The intrinsic variability of volatile organic compound emissions and photosynthetic parameters in response to two drying cycles was investigated on Quercus suber L. saplings originating from three Tunisian populations native to contrasting climates. Emissions mainly included monoterpenes plus traces of sesquiterpenes and methylsalicylate that steadily decreased during the experiment unrelated to treatments. Instead, monoterpene emissions increased by 30% during a

Michael Staudt; Amel Ennajah; Florent Mouillot; Richard Joffre

2008-01-01

162

A novel approach to emission modelling of biogenic volatile organic compounds in Europe: improved seasonality and land-cover  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOC) emitted from vegetation are important for the formation of secondary pollutants such as ozone and secondary organic aerosols (SOA) in the atmosphere. Therefore, BVOC emission are an important input for air quality models. To model these emissions with high spatial resolution, the accuracy of the underlying vegetation inventory is crucial. We present a BVOC emission model that accommodates different vegetation inventories and uses satellite-based measurements of greenness instead of pre-defined vegetation periods. This approach to seasonality implicitly treats effects caused by water or nutrient availability, altitude and latitude on a plant stand. Additionally, we test the influence of proposed seasonal variability in enzyme activity on BVOC emissions. In its present setup, the emission model calculates hourly emissions of isoprene, monoterpenes, sesquiterpenes and the oxygenated volatile organic compounds (OVOC) methanol, formaldehyde, formic acid, ethanol, acetaldehyde, acetone and acetic acid. In this study, emissions based on three different vegetation inventories are compared with each other and diurnal and seasonal variations in Europe are investigated for the year 2006. Two of these vegetation inventories require information on tree-cover as an input. We compare three different land-cover inventories (USGS GLCC, GLC2000 and Globcover 2.2) with respect to tree-cover. The often-used USGS GLCC land-cover inventory leads to a severe reduction of BVOC emissions due to a potential miss-attribution of broad-leaved trees and reduced tree-cover compared to the two other land-cover inventories. To account for uncertainties in the land-cover classification, we introduce land-cover correction factors for each relevant land-use category to adjust the tree-cover. The results are very sensitive to these factors within the plausible range. For June 2006, total monthly BVOC emissions decreased up to -27% with minimal and increased up to +71% with maximal factors, while in January 2006, the changes in monthly BVOC emissions were -54 and +56% with minimal and maximal factors, respectively. The new seasonality approach leads to a reduction in the annual emissions compared with non-adjusted data. The strongest reduction occurs in OVOC (up to -32%), the weakest in isoprene (as little as -19%). If also enzyme seasonality is taken into account, however, isoprene reacts with the steepest decrease of annual emissions, which are reduced by -44% to -49%, annual emissions of monoterpenes reduce between -30 and -35%. The sensitivity of the model to changes in temperature depends on the climatic zone but not on the vegetation inventory. The sensitivity is higher for temperature increases of 3 K (+31% to +64%) than decreases by the same amount (-20 to -35%). The climatic zones "Cold except summer" and "arid" are most sensitive to temperature changes in January for isoprene and monoterpenes, respectively, while in June, "polar" is most sensitive to temperature for both isoprene and monoterpenes. Our model predicts the oxygenated volatile organic compounds to be the most abundant fraction of the annual European emissions (3571-5328 Gg yr-1), followed by monoterpenes (2964-4124 Gg yr-1), isoprene (1450-2650 Gg yr-1) and sesquiterpenes (150-257 Gg yr-1). We find regions with high isoprene emissions (most notably the Iberian Peninsula), but overall, oxygenated VOC dominate with 43-45% (depending on the vegetation inventory) contribution to the total annual BVOC emissions in Europe. Isoprene contributes between 18-21%, monoterpenes 33-36% and sesquiterpenes contribute 1-2%. We compare the concentrations of biogenic species simulated by an air quality model with measurements of isoprene and monoterpenes in Hohenpeissenberg (Germany) for both summer and winter. The agreement between observed and modelled concentrations is better in summer than in winter. This can partly be explained with the difficulty to model weather conditions in winter accurately, but also with the increased an

Oderbolz, D. C.; Aksoyoglu, S.; Keller, J.; Barmpadimos, I.; Steinbrecher, R.; Skjøth, C. A.; Plaß-Dülmer, C.; Prévôt, A. S. H.

2012-08-01

163

A comprehensive emission inventory of biogenic volatile organic compounds in Europe: improved seasonality and land-cover  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOC) emitted from vegetation are important for the formation of secondary pollutants such as ozone and secondary organic aerosols (SOA) in the atmosphere. Therefore, BVOC emission are an important input for air quality models. To model these emissions with high spatial resolution, the accuracy of the underlying vegetation inventory is crucial. We present a BVOC emission model that accommodates different vegetation inventories and uses satellite-based measurements of greenness instead of pre-defined vegetation periods. This approach to seasonality implicitly treats effects caused by water or nutrient availability, altitude and latitude on a plant stand. Additionally, we test the influence of proposed seasonal variability in enzyme activity on BVOC emissions. In its present setup, the emission model calculates hourly emissions of isoprene, monoterpenes, sesquiterpenes and the oxygenated volatile organic compounds (OVOC) methanol, formaldehyde, formic acid, ethanol, acetaldehyde, acetone and acetic acid. In this study, emissions based on three different vegetation inventories are compared with each other and diurnal and seasonal variations in Europe are investigated for the year 2006. Two of these vegetation inventories require information on tree-cover as an input. We compare three different land-cover inventories (USGS GLCC, GLC2000 and Globcover 2.2) with respect to tree-cover. The often-used USGS GLCC land-cover inventory leads to a severe reduction of BVOC emissions due to a potential miss-attribution of broad-leaved trees and reduced tree-cover compared to the two other land-cover inventories. To account for uncertainties in the land-cover classification, we introduce land-cover correction factors for each relevant land-use category to adjust the tree-cover. The results are very sensitive to these factors within the plausible range. For June 2006, total monthly BVOC emissions decreased up to -27% with minimal and increased up to +71% with maximal factors, while in January 2006, the changes in monthly BVOC emissions were -54 and +56% with minimal and maximal factors, respectively. The new seasonality approach leads to a reduction in the annual emissions compared with non-adjusted data. The strongest reduction occurs in OVOC (up to -32%), the weakest in isoprene (as little as -19%). If also enzyme seasonality is taken into account, however, isoprene reacts with the steepest decrease of annual emissions, which are reduced by -44% to -49%, annual emissions of monoterpenes reduce between -30 and -35%. The sensitivity of the model to changes in temperature depends on the climatic zone but not on the vegetation inventory. The sensitivity is higher for temperature increases of 3 K (+31% to +64%) than decreases by the same amount (-20 to -35%). The climatic zones "Cold except summer" and "arid" are most sensitive to temperature changes in January for isoprene and monoterpenes, respectively, while in June, "polar" is most sensitive to temperature for both isoprene and monoterpenes. Our model predicts the oxygenated volatile organic compounds to be the most abundant fraction of the annual European emissions (3571-5328 Gg yr-1), followed by monoterpenes (2964-4124 Gg yr-1), isoprene (1450-2650 Gg yr-1) and sesquiterpenes (150-257 Gg yr-1). We find regions with high isoprene emissions (most notably the Iberian Peninsula), but overall, oxygenated VOC dominate with 43-45% (depending on the vegetation inventory) contribution to the total annual BVOC emissions in Europe. Isoprene contributes between 18-21%, monoterpenes 33-36% and sesquiterpenes contribute 1-2%. We compare the concentrations of biogenic species simulated by an air quality model with measurements of isoprene and monoterpenes in Hohenpeissenberg (Germany) for both summer and winter. The agreement between observed and modelled concentrations is better in summer than in winter. This can partly be explained with the difficulty to model weather conditions in winter accurately, but also with the increased an

Oderbolz, D. C.; Aksoyoglu, S.; Keller, J.; Barmpadimos, I.; Steinbrecher, R.; Skjøth, C. A.; Plaß-Dülmer, C.; Prévôt, A. S. H.

2013-02-01

164

Headspace solid-phase microextraction--comprehensive two-dimensional gas chromatography of wound induced plant volatile organic compound emissions.  

PubMed

Plant emissions of volatile organic compounds from mechanically wounded Agrostis stolonifera, Pennisetum clandestinum, Eucalyptus leucoxylon and Trifolium repens have been sampled by headspace-solid phase microextraction (HS-SPME) and analysed by using comprehensive two-dimensional gas chromatography (GCxGC) for measurement of the plant emissions. GCxGC produces a fingerprint of the volatile organic compounds in a 2D separation space that may be approximately interpreted as a boiling point-polarity space, and may then be presented as a two-dimensional contour plot. This allows identification of sample-dependent variations in component distributions in the 2D plot, which will contain information about plant differences and should therefore facilitate recognition of different plant materials and displays the gross differences in volatiles between each plant species. PMID:12537367

Perera, Ranjini M M; Marriott, Philip J; Galbally, Ian E

2002-12-01

165

Characteristics of carbonyl compounds emission from a diesel-engine using biodiesel–ethanol–diesel as fuel  

Microsoft Academic Search

Characteristics of carbonyl compounds (carbonyls) emissions from biodiesel–ethanol–diesel (BE–diesel) were investigated in a Commins-4B diesel engine and compared with those from fossil diesel. Acetaldehyde was the most abundant carbonyls in the exhaust, followed by formaldehyde, acetone, propionaldehyde and benzaldehyde. Apliphatic carbonyls emitted from BE–diesel were higher than those from diesel fuel, while formaldehyde and aromatic carbonyls were less than those

Xiaobing Pang; Xiaoyan Shi; Yujing Mu; Hong He; Shijin Shuai; Hu Chen; Rulong Li

2006-01-01

166

Quantifying Marine Emissions of Biogenic Volatile Organic Compounds Using Laboratory Measurements of Plankton Monocultures and Field Samples  

Microsoft Academic Search

Marine biogenic volatile organic compounds (BVOCs) have been suggested to contribute significant portion of the organic carbon present in ocean atmosphere. In this study emission rates of 40 different hydrocarbons are quantified for lab-grown non-axenic phytoplankton monocultures and ambient samples from the Pamlico-Neuse Estuary, NC. The outcome of environmental conditions on production of BVOCs was examined for different light and

A. W. Sabolis; N. Meskhidze; D. Kamykowski; R. E. Reed

2010-01-01

167

Emissions of biogenic sulphur compounds from several wetland soils in Florida  

NASA Astrophysics Data System (ADS)

Emission rates of the biogenic sulphur gases hydrogen sulphide, dimethyl sulphide, carbon disulphide and dimethyl disulphide have been measured from the exposed soils of five wetland plant communities in Florida. Dimethyl sulphide and hydrogen sulphide were the predominant species emitted. All the studied ecosystems showed diel variation in the emission rates of the biogenic sulphur gases with the highest emissions rates occurring early- to mid-afternoon, and the lowest emission rates occurring during the early morning. The relative magnitude of emissions from the individual ecosystems followed the trend Distichlis spicata > Avicennia germinans > Batis maritima ? Juncus roemerianus ? Cladium jamaicense. Only the emission rates from the peaty D. spicata site are comparable in magnitude to previous emission measurements in wetland ecosystems of Spartina alterniflora and associated mud flats.

Cooper, W. J.; Cooper, D. J.; Saltzman, E. S.; Mello, W. Z. de; Savoie, D. L.; Zika, R. G.; Prospero, J. M.

168

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

PubMed

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

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

2011-01-01

169

Air-surface exchange of nonmethane organic compounds at a Grassland site: seasonal variations and stressed emissions.  

SciTech Connect

Emissions of nonmethane organic compounds (NMOCs) were measured by a static enclosure technique at a grassland site in the Midwestern United States during the growing seasons over a 2-year period. A mixture of nonmethane hydrocarbons (NMHCs) and oxygenated hydrocarbons (OxHCs) was emitted from the surface at rates exhibiting large seasonal and year-to-year variations. The average emission rate (and standard error) of the total NMOCs around noontime on sunny days during the growing seasons for the 2-year period was 1,300 {+-} 170 {micro}g m-2 h-1 (mass of the total NMOCs per area of enclosed soil surface per hour) or 5.5 {+-} 0.9 {micro}g g-1 h-1 (mass of the total NMOCs per mass of dry plant biomass in an enclosure per hour), with about 10% and 70% of the emissions being composed of tentatively identified NMHCs and OxHCs, respectively. Methanol was apparently derived from both the soil and vegetation and exhibited an average emission rate of 460 {+-} 73 {micro}g m-2 h-1 (1.4 {+-} 0.2 {micro}g g-1 h-1), which was the largest emission among the NMOCs. The year-to-year variation in the precipitation pattern greatly affected the NMOC emission rates. Emission rates normalized to biomass density exhibited a linear decrease as the growing season progressed. The emission rates of some NMOCs, particularly the OxHCs, from vegetation subjected to hypoxia, frost, and physical stresses were significantly greater than the average values observed at the site. Emissions of monoterpenes (a- and {beta}-pinene, limonene, and myrcene) and cis-3-hexen-1-ol were accelerated during the flowering of the plants and were much greater than those predicted by algorithms that correlated emission rates with temperature. Herbaceous vegetation is estimated to contribute about 40% and 50% of the total NMOC and monoterpene emissions, respectively, in grasslands; the remaining contributions are from woody species within grasslands. Contributions of isoprene emissions from herbaceous vegetation in grasslands are negligible. Grasslands are estimated to contribute about 10% of the total biogenic NMOC emissions in the United States.

Fukui, Y.; Doskey, P. V.; Environmental Research

1998-06-20

170

An improved model for estimating emissions of volatile organic compounds from forests in the eastern United States  

NASA Astrophysics Data System (ADS)

Regional estimates of biogenic volatile organic compound (BVOC) emissions are important inputs for models of atmospheric chemistry and carbon budgets. Since forests are the primary emitters of BVOCs, it is important to develop reliable estimates of their areal coverage and BVOC emission rate. A new system is developed to estimate these emissions for specific tree genera at hourly and county level resolution. The U.S. Department of Agriculture, Forest Service Forest Inventory and Analysis Eastwide Database is used to describe the areal extent, species composition, and tree diameter distributions of United States forests. Horizontal canopy occupancy by genera is then estimated as a function of diameter at breast height. Growing season peak foliar masses are derived from the empirical literature for canopies of deciduous and coniferous genera. A simple canopy model is used to adjust photosynthetically active solar radiation at five vertical levels in the canopy. Leaf temperature and photosynthetically active radiation derived from ambient conditions above the forest canopy are then used to drive empirical equations to estimate genus level emission rates of BVOCs vertically through forest canopies. These genera level estimates are then aggregated to regional levels for comparison with the regulatory model currently used and for input into air quality models. The proposed model yields isoprene emission rate estimates for specific countries that are 5 to 10 times higher (and total BVOC emission rates that are 3 to 5 times higher) than the Environmental Protection Agency BVOC emission rate model currently used. Emission estimates of isoprene and monoterpenes from the new system compare favorably with rates measured at various forested sites in the United States.

Geron, Christopher D.; Guenther, Alex B.; Pierce, Thomas E.

1994-06-01

171

Influence of bio-fuels on passenger car vehicle emissions  

NASA Astrophysics Data System (ADS)

In order to reduce the emissions of air pollutants, vehicles design and fuel formulation have changed. Ultra clean vehicle technologies started to be used in increased number. As a result, the emissions composition is expected to change as well. The use of new technologies and new fuels require new emissions tests especially for non-regulated compounds. The interest in using bio fuels as alternative fuels for petroleum-based ones has increased constantly in the last years. The advantages of the bio fuels usage is given by their similar proprieties, characteristics of renew ability, biodegradability and potential beneficial effects on the exhaust emission. The study involved measurements on a roller test facility of a reference passenger car representing new technologies (emission standards, injection system). The vehicle operated by use of reference gasoline and reference gasoline blended (10 and 20%) with bio-ethanol (EtOH). The measurements used different driving cycles: ARTEMIS cycle, real world driving cycle, NEDC cycle, the standard European driving cycle and additionally, a driving cycle consisting in Idle, 30, 50, 90 km/h. The sampling positions were before and after the catalyst and in the exhaust pipe. The detailed speciation of NMVOC' (non methane volatile organic compounds) was completed by use of active carbon tubes, DNPH (2,4-dinitrophenylhydrazine) tubes and cold traps. The particles were monitored by use of an on-line EEPS (Engine Exhaust Particle Sizer). CO2, NO, NO2 and NOX (NO +NO2) were continuously monitored by use of an on- line FTIR (Fourier transform infrared spectroscopy)- MEXA system. The investigations reveal that among the carbonylic compounds 15 oxygenated species were found in engine out exhaust and only 3 in tailpipe emissions, namely formaldehyde, acetaldehyde and acroleine. These are of great interest due to their impacts on human health. The hydrocarbons emissions decrease by increased of EtOH content. New compounds were observed. The nitro-compounds found in the after engine position by increased EtOH were no more found in the exhaust gas. The results show that total particle concentration, mass and diameter decreased substantially after catalyst and filter by increased ethanol blend.

Petrea, M.; Kapernaum, M.; Wahl, C.

2009-04-01

172

Global fire emission estimates (2007-2012) derived from inversion of formaldehyde columns  

NASA Astrophysics Data System (ADS)

Wildfires have a strong impact on the chemistry and composition of the atmosphere and the radiative forcing. The fire emission estimates bear, however, important uncertainties due to the limited amount of field measurements, uncertainties in satellite burned area products, as well as empirical relations used for fuel type allocations. Atmospheric inversions are an alternative approach that provides new independent constraints on the fire estimates. This method involves measurements of trace gases combined with atmospheric models, where optimization algorithms are used to minimize the discrepancy between the model and the observations by adjusting the emission estimates. In this communication, we present global emission estimates of non-methane volatile organic compounds (NMVOCs), inferred from inversion of formaldehyde (HCHO) columns retrieved from the Global Ozone Monitoring Experiment-2 (GOME-2) instrument (De Smedt et al., 2012). The IMAGESv2 global CTM provides the relationship between the emissions and the vertical columns. The Global Fire Emissions Database version 3 (GFEDv3, van der Werf et al., 2010) is used as a priori bottom-up inventory in the model. The agreement between formaldehyde columns calculated by the IMAGESv2 model and the formaldehyde columns from GOME-2 is optimized using the adjoint modelling technique (Stavrakou et al., 2009). The obtained top-down fire emission estimates between 2007 and 2012 are available at the GlobEmission data portal (http://www.globemission.eu) on a monthly basis and at 0.5°x0.5° spatial resolution. The emission estimates are evaluated against three independent emission inventories: GFEDv3 (van der Werf et al., 2010), GFAS (Kaiser et al., 2012) and FINN (Wiedinmyer et al., 2011). Furthermore, simulated CO columns over the fire-affected regions will be compared with CO columns retrieved from the IASI sensor (George et al., 2009).

Bauwens, Maite; Stavrakou, Trissevgeni; Müller, Jean-Francois; De Smedt, Isabelle; Van Roozendael, Michel

2014-05-01

173

The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period 1990-2030  

NASA Astrophysics Data System (ADS)

To explore the relationship between tropospheric ozone and radiative forcing with changing emissions, we compiled two sets of global scenarios for the emissions of the ozone precursors methane (CH4), carbon monoxide (CO), non-methane volatile organic compounds (NMVOC) and nitrogen oxides (NOx) up to the year 2030 and implemented them in two global Chemistry Transport Models. The "Current Legislation" (CLE) scenario reflects the current perspectives of individual countries on future economic development and takes the anticipated effects of presently decided emission control legislation in the individual countries into account. In addition, we developed a "Maximum technically Feasible Reduction" (MFR) scenario that outlines the scope for emission reductions offered by full implementation of the presently available emission control technologies, while maintaining the projected levels of anthropogenic activities. Whereas the resulting projections of methane emissions lie within the range suggested by other greenhouse gas projections, the recent pollution control legislation of many Asian countries, requiring introduction of catalytic converters for vehicles, leads to significantly lower growth in emissions of the air pollutants NOx, NMVOC and CO than was suggested by the widely used and more pessimistic IPCC (Intergovernmental Panel on Climate Change) SRES (Special Report on Emission Scenarios) scenarios (Nakicenovic et al., 2000), which made Business-as-Usual assumptions regarding emission control technology. With the TM3 and STOCHEM models we performed several long-term integrations (1990-2030) to assess global, hemispheric and regional changes in CH4, CO, hydroxyl radicals, ozone and the radiative climate forcings resulting from these two emission scenarios. Both models reproduce broadly the observed trends in CO, and CH4 concentrations from 1990 to 2002.

For the "current legislation" case, both models indicate an increase of the annual average ozone levels in the Northern Hemisphere by 5ppbv, and up to 15ppbv over the Indian sub-continent, comparing the 2020s (2020-2030) with the 1990s (1990-2000). The corresponding higher ozone and methane burdens in the atmosphere increase radiative forcing by approximately 0.2 Wm-2. Full application of today's emissions control technologies, however, would bring down ozone below the levels experienced in the 1990s and would reduce the radiative forcing of ozone and methane to approximately -0.1 Wm-2. This can be compared to the 0.14-0.47 Wm-2 increase of methane and ozone radiative forcings associated with the SRES scenarios. While methane reductions lead to lower ozone burdens and to less radiative forcing, further reductions of the air pollutants NOx and NMVOC result in lower ozone, but at the same time increase the lifetime of methane. Control of methane emissions appears an efficient option to reduce tropospheric ozone as well as radiative forcing.

Dentener, F.; Stevenson, D.; Cofala, J.; Mechler, R.; Amann, M.; Bergamaschi, P.; Raes, F.; Derwent, R.

2005-07-01

174

Cleaner co-combustion of lignite-biomass-waste blends by utilising inhibiting compounds of toxic emissions.  

PubMed

In this paper, the co-combustion behaviour of coal with wastes and biomass and the related toxic gaseous emissions were investigated. The objective of this work is to add on towards a cleaner co-combustion of lignite-waste-biomass blends by utilizing compounds that could inhibit the formation of toxic pollutants. A series of co-combustion tests was performed in a pilot scale incinerator, and the emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured. The co-combustion behaviour of lignite with olive kernels, MDF and sawdust was studied and the ability of additives such as urea, almond shells and municipal sewage sludge to reduce the PCDD/F emissions was examined. All blends were proven good fuels and reproducible combustion conditions were achieved. The addition of inhibitors prior to combustion showed in some cases, relatively high PCDD/F emissions reduction. Among the inhibitors tested, urea seems to achieve a reduction of PCDD/F emissions for all fuel blends, while an unstable behaviour was observed for the others. PMID:17204304

Skodras, G; Palladas, A; Kaldis, S P; Sakellaropoulos, G P

2007-04-01

175

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

EPA Science Inventory

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

176

Volcanic Emissions of Halides and Sulfur Compounds to the Troposphere and Stratosphere  

Microsoft Academic Search

Estimates have been made of the annual emissions of HC1, HF, and SO2 to the troposphere and stratosphere from volcanic eruptions. The estimated annual emission rates to the troposphere are 7.5 X 105, 3.8 X 104, and 7.5 X 106 metric tons, respectively, and those to the stratosphere are 2.8 x 104, 1.4 x 10 a, and 2.8 X 105,

Richard D. Cadle

1975-01-01

177

Detection of emission indices of aircraft exhaust compounds by open-path optical methods at airports  

NASA Astrophysics Data System (ADS)

Air pollutant emission rates of aircrafts are determined with test bed measurements. Regulations exist for CO2, NO, NO2, CO concentrations, the content of total unburned hydrocarbons and the smoke number, a measure of soot. These emission indices are listed for each engine in a data base of the International Civil Aviation Organisation (ICAO) for four different Air pollutant emission rates of aircrafts are determined with test bed measurements. Regulations exist for CO2, NO, NO2, CO concentrations, the content of total unburned hydrocarbons and the smoke number, a measure of soot. These emission indices are listed for each engine in a data base of the International Civil Aviation Organisation (ICAO) for four different thrust levels (Idle, approach, cruise and take-off). It is a common procedure to use this data base as a starting point to estimate aircraft emissions at airports and further on to calculate the contribution of airports on local air quality. The comparison of these indices to real in use measurements therefore is a vital task to test the quality of air quality models at airports. Here a method to determine emission indices is used, where concentration measurements of CO2 together with other pollutants in the aircraft plume are needed. During intensive measurement campaigns at Zurich (ZRH) and Paris Charles De Gaulle (CDG) airports, concentrations of CO2, NO, NO2 and CO were measured. The measurement techniques were Fourier-Transform-Infrared (FTIR) spectrometry and Differential Optical Absorption Spectroscopy (DOAS). The big advantage of these methods is that no operations on the airport are influenced during measurement times. Together with detailed observations of taxiway movements, a comparison of emission indices with real in use emissions is possible.

Schürmann, Gregor; Schäfer, Klaus; Jahn, Carsten; Hoffmann, Herbert; Utzig, Selina

2005-10-01

178

Biogenic volatile organic compound emissions from nine tree species used in an urban tree-planting program  

NASA Astrophysics Data System (ADS)

The biogenic volatile organic compound (BVOC) emissions of nine urban tree species were studied to assess the air quality impacts from planting a large quantity of these trees in the City and County of Denver, Colorado, through the Mile High Million tree-planting initiative. The deciduous tree species studied were Sugar maple, Ohio buckeye, northern hackberry, Turkish hazelnut, London planetree, American basswood, Littleleaf linden, Valley Forge elm, and Japanese zelkova. These tree species were selected using the i-Tree Species Selector (itreetools.org). BVOC emissions from the selected tree species were investigated to evaluate the Species Selector data under the Colorado climate and environmental growing conditions. Individual tree species were subjected to branch enclosure experiments in which foliar emissions of BVOC were collected onto solid adsorbent cartridges. The cartridge samples were analyzed for monoterpenes (MT), sesquiterpenes (SQT), and other C10-C15 BVOC using thermal desorption-gas chromatography-flame ionization detection/mass spectroscopy (GC-FID/MS). Individual compounds and their emission rates (ER) were identified. MT were observed in all tree species, exhibiting the following total MT basal emission rates (BER; with a 1-? lower bound, upper bound uncertainty window): Sugar maple, 0.07 (0.02, 0.11) ?g g-1 h-1; London planetree, 0.15 (0.02, 0.27) ?g g-1 h-1; northern hackberry, 0.33 (0.09, 0.57) ?g g-1 h-1; Japanese zelkova, 0.42 (0.26, 0.58) ?g g-1 h-1; Littleleaf linden, 0.71 (0.33, 1.09) ?g g-1 h-1; Valley Forge elm, 0.96 (0.01, 1.92) ?g g-1 h-1; Turkish hazelnut, 1.30 (0.32, 2.23) ?g g-1 h-1; American basswood, 1.50 (0.40, 2.70) ?g g-1 h-1; and Ohio buckeye, 6.61 (1.76, 11.47) ?g g-1 h-1. SQT emissions were seen in five tree species with total SQT BER of: London planetree, 0.11 (0.01, 0.20) ?g g-1 h-1; Japanese zelkova, 0.11 (0.05, 0.16) ?g g-1 h-1; Littleleaf linden, 0.13 (0.06, 0.21) ?g g-1 h-1; northern hackberry, 0.20 (0.11, 0.30) ?g g-1 h-1; and Ohio buckeye, 0.44 (0.06, 0.83) ?g g-1 h-1. The following trees exhibited emissions of other C10-C15 volatile organic compounds (VOC): Littleleaf linden, 0.15 (0.10, 0.20) ?g g-1 h-1; Ohio buckeye, 0.39 (0.14, 0.65) ?g g-1 h-1; and Turkish hazelnut, 0.72 (0.49, 0.95) ?g g-1 h-1. All tree species studied in this experiment were confirmed to be low isoprene emitters. Compared to many other potential urban tree species, the selected trees can be considered low to moderate BVOC emitters under Colorado growing conditions, with total emission rates one-tenth to one-hundredth the rates of potential high-BVOC emitting trees. The emissions data were used to estimate the impact of this targeted tree planting on the urban BVOC flux and atmospheric VOC burden. Selecting the low-emitting tree species over known high BVOC emitters is equivalent to avoiding VOC emissions from nearly 500,000 cars from the inner city traffic.

Curtis, A. J.; Helmig, D.; Baroch, C.; Daly, R.; Davis, S.

2014-10-01

179

Volatile organic compound and formaldehyde emissions from Populus davidiana wood treated with low molecular weight urea-formaldehyde resin.  

PubMed

Populus davidiana wood was usually impregnated with low molecular weight thermosetting resins to improve its physical and mechanical properties. However, volatile organic compounds (VOCs) and formaldehyde emitted from treated wood have lead to poor indoor air quality (IAQ). The trends of VOC and formaldehyde emissions as a function of the weight percent gain (WPG) factor were mainly investigated in this work. Aldehydes and alkanes were the predominant compositions indentified in the VOC emissions, although low amount of ketones, terpenes and alcohols were also found. With the increase in WPG, VOC and formaldehyde concentrations improved. However, their concentration began to decrease when WPG was over 44.06% (VOC) and 36.35% (formaldehyde), respectively. The modulus of elasticity (MOE) of untreated and treated wood at different WPG levels was detected. It showed that treatment of wood with UF resin significantly improved the mechanical properties. Therefore, it is probably helpful to comprehensively analyze correlations among environmental performance, mechanical performance and processing costs. PMID:25204077

Wang, Jing-Xian; Shen, Jun; Lei, Cheng-Shuai; Feng, Qi

2014-09-01

180

Carbonyl compound emissions from a heavy-duty diesel engine fueled with diesel fuel and ethanol-diesel blend.  

PubMed

This paper presents an investigation of the carbonyl emissions from a direct injection heavy-duty diesel engine fueled with pure diesel fuel (DF) and blended fuel containing 15% by volume of ethanol (E/DF). The tests have been conducted under steady-state operating conditions at 1200, 1800, 2600 rpm and idle speed. The experimental results show that acetaldehyde is the most predominant carbonyl, followed by formaldehyde, acrolein, acetone, propionaldehyde and crotonaldehyde, produced from both fuels. The emission factors of total carbonyls vary in the range 13.8-295.9 mg(kWh)(-1) for DF and 17.8-380.2mg(kWh)(-1) for E/DF, respectively. The introduction of ethanol into diesel fuel results in a decrease in acrolein emissions, while the other carbonyls show general increases: at low engine speed (1200 rpm), 0-55% for formaldehyde, 4-44% for acetaldehyde, 38-224% for acetone, and 5-52% for crotonaldehyde; at medium engine speed (1800 rpm), 106-413% for formaldehyde, 4-143% for acetaldehyde, 74-113% for acetone, 114-1216% for propionaldehyde, and 15-163% for crotonaldehyde; at high engine speed (2600 rpm), 36-431% for formaldehyde, 18-61% for acetaldehyde, 22-241% for acetone, and 6-61% for propionaldehyde. A gradual reduction in the brake specific emissions of each carbonyl compound from both fuels is observed with increase in engine load. Among three levels of engine speed employed, both DF and E/DF emit most CBC emissions at high engine speed. On the whole, the presence of ethanol in diesel fuel leads to an increase in aldehyde emissions. PMID:20416922

Song, Chonglin; Zhao, Zhuang; Lv, Gang; Song, Jinou; Liu, Lidong; Zhao, Ruifen

2010-05-01

181

Volatile organic compound emissions from the oil and natural gas industry in the Uintah Basin, Utah: oil and gas well pad emissions compared to ambient air composition  

NASA Astrophysics Data System (ADS)

Emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uintah Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aromatics, alkanes, cycloalkanes and methanol were observed for extended periods of time and for short-term spikes caused by local point sources. The mixing ratios during the time the mobile laboratory spent on the well pads were averaged. High mixing ratios were found close to all point sources, but gas well pads with collection and dehydration on the well pad were clearly associated with higher mixing ratios than other wells. The comparison of the VOC composition of the emissions from the oil and natural gas well pads showed that gas well pads without dehydration on the well pad compared well with the majority of the data at Horse Pool, and that oil well pads compared well with the rest of the ground site data. Oil well pads on average emit heavier compounds than gas well pads. The mobile laboratory measurements confirm the results from an emissions inventory: the main VOC source categories from individual point sources are dehydrators, oil and condensate tank flashing and pneumatic devices and pumps. Raw natural gas is emitted from the pneumatic devices and pumps and heavier VOC mixes from the tank flashings.

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

2014-10-01

182

Regional biogenic emissions of reactive volatile organic compounds (BVOC) from forests: First results on process studies, modelling and validation experiments (BEWA2000)  

Microsoft Academic Search

The overall objective of the research consortia is to develop for a forest canopy a prognostic, validated emission model for primary and secondary volatile organic compounds (VOC) to be used for estimating regional biogenic emissions with a higher spatial and temporal resolution than present. To achieve this objective requires a better description of biosynthetic processes as well as chemical degradation

B. Rappenglück

2003-01-01

183

Analysis of C1, C2, and C10 through C33 particle-phase and semi-volatile organic compound emissions from heavy-duty diesel engines  

E-print Network

from heavy-duty diesel engines Z. Gerald Liu a,*, Devin R. Berg a , Victoria N. Vasys a , Melissa E 18 November 2009 Keywords: Organic compound emissions Particulate matter emissions Heavy-duty diesel engines Aftertreatment technology Diesel particulate filter Chemical speciation a b s t r a c t To meet

Wu, Mingshen

184

Emissions of terpenoids, benzenoids, and other biogenic gas-phase organic compounds from agricultural crops and their potential implications for air quality  

NASA Astrophysics Data System (ADS)

Agriculture comprises a substantial fraction of land cover in many regions of the world, including California's San Joaquin Valley, which is out of compliance with state and federal standards for tropospheric ozone and particulate matter (PM2.5). Emissions from vegetation and other biogenic and anthropogenic sources react in the atmosphere to produce ozone and secondary organic aerosol, which comprises a substantial fraction of PM2.5. Using data from three measurement campaigns, we examine emissions of reactive gas-phase organic carbon from agricultural crops and their potential to impact regional air quality relative to anthropogenic emissions in California's San Joaquin Valley. Emission rates for a suite of biogenic terpenoid compounds were measured in a greenhouse for 25 representative crops from California in 2008, and ambient measurements of terpenoids and other biogenic compounds in the volatile and intermediate-volatility organic compound range were made over an orange orchard in a rural area of the San Joaquin Valley during two seasons in 2010: summer and spring flowering. When accounting for both emissions of reactive precursors and the deposition of ozone to an orange orchard, the net effect of the orange trees is a net source of ozone in the springtime during flowering, and relatively neutral for most of the summer until the fall when it becomes a sink. Flowering was a major emission event and caused a large increase in emissions including a suite of compounds that had not been measured in the atmosphere before. Such biogenic emission events need to be better parameterized in models as they have significant potential to impact regional air quality since emissions increase by an order of magnitude. In regions like the San Joaquin Valley, the mass of biogenic emissions from agricultural crops during the summer (without flowering) and the potential ozone and secondary organic aerosol formation from these emissions are on the same order as anthropogenic emissions from motor vehicles and must be considered in air quality models and secondary pollution control strategies.

Gentner, D. R.; Ormeño, E.; Fares, S.; Ford, T. B.; Weber, R.; Park, J.-H.; Brioude, J.; Angevine, W. M.; Karlik, J. F.; Goldstein, A. H.

2013-11-01

185

Reducing Emissions of Volatile Organic Compounds - Final Report - 08/15/1997 - 02/14/2001  

SciTech Connect

The overall objective of this research was to determine if the shallow suspended growth reactor (SSGR) could provide sufficient treatment performance of organic and reduced sulfur (TRS) compounds, at 50 C to meet the EPA ''cluster rule'' regulatory limits. The biodegradation of a mixture of organic compounds that could be present in pulp and paper high volume low concentration gas streams was evaluated at 50 C in a bench-scale SSGR. The removal of methanol was followed in particular, and was mathematically modeled to evaluate the effect of process design and operating parameters on methanol removal. Additional tests were performed to obtain mass transfer and biodegradation kinetic parameters for the model. The acclimation of microbial populations capable of degrading TRS compounds from various seed sources was studied in batch reactors at 30 and 50 C. The degradation of TRS compounds in bench-scale SSGR was studied at 20-50 C. Also, the biodegradation kinetic and mass transfer coefficients for alpha-terpinene and gamma-terpinene were studied. Finally, a pilot plant was constructed and operated at Simpson pulp and paper mill in Tacoma, WA.

Stensel, H. David; Strand, Stuart E.

2001-03-14

186

Volatile organic compound emissions from automobile refinishing: Background information for promulgated standards. Final report  

SciTech Connect

A final rule for the regulation of volatile organic compounds (VOC) from automobile refinishing is being promulgated under the authority of Section 183(e) of the Clean Air Act. This document contains comments received from the public, and the EPA`s responses to these comments.

NONE

1998-08-01

187

Emissions of isoprenoids and oxygenated biogenic volatile organic compounds from a New England mixed forest  

Microsoft Academic Search

Fluxes of biogenic volatile organic compounds, including isoprene, monoterpenes, and oxygenated VOCs measured above a mixed forest canopy in central Massachusetts during the 2005 and 2007 growing seasons are reported. Mixing ratios were measured using proton transfer reaction mass spectrometry (PTR-MS) and fluxes computed by the disjunct eddy covariance technique. Isoprene was by far the predominant BVOC emitted at this

K. A. McKinney; B. H. Lee; A. Vasta; T. V. Pho; J. W. Munger

2011-01-01

188

Emissions of isoprenoids and oxygenated biogenic volatile organic compounds from a New England mixed forest  

Microsoft Academic Search

Fluxes of biogenic volatile organic compounds, including isoprene, monoterpenes, and oxygenated VOCs measured above a mixed forest canopy in western Massachusetts during the 2005 and 2007 growing seasons are reported. Measurements were made using proton transfer reaction mass spectrometry (PTR-MS) and converted to fluxes using the disjunct eddy covariance technique. Isoprene was by far the predominant BVOC emitted at this

K. A. McKinney; B. H. Lee; A. Vasta; T. V. Pho; J. W. Munger

2010-01-01

189

EMISSION OF ORGANIC COMPOUNDS AND COMBUSTION GASES DURING HAZARDOUSWASTE COFIRING IN A WATERTUBE PACKAGE BOILER  

EPA Science Inventory

The primary objective of this study was to evaluate the sorptionand desorption of organic compounds on combustion-generated sootduring the cofiring of hazardous organics with fuel oil in afull-scale boiler. orption of organics was accomplished by firinga watertube package boiler ...

190

Volatile acetic acid and formaldehyde emission from plywood treated with boron compound  

Microsoft Academic Search

The effects of plywood on formaldehyde and volatile acetic acid emissions treated with borax and boric acid were investigated. The treated plywood samples were manufactured by using two different methods; each veneer was first impregnated by a dipping method before the first group of plywood was manufactured. The second group of plywood panels was produced by adding preservatives (borax, boric

S. Colak; G. Colakoglu

2004-01-01

191

X-RAY EMISSION ANALYSIS OF PLUTONIUM AND URANIUM COMPOUND MIXTURES  

Microsoft Academic Search

A timesaving and reliable x-ray emission method was developed for the ; simultaneous determination of plutonium and uranium in refractory oxide mixtures ; and fused alloys. The measurements of characteristic L alpha lines of uranium ; and plutonium, with thorium used as an internal standard, were carried out after ; a fusion of the refractory mixtures in a flux of

Oscar Menis; E. K. Halteman; E. E. Garcia

1963-01-01

192

Volatile Organic Compound Emission from Quercus suber, Quercus canariensis, and its hybridisation product Quercus afares  

NASA Astrophysics Data System (ADS)

Oaks represent one of the most important plant genera in the Northern hemisphere and include many intensively VOC emitting species. The major group constitutes the isoprene emitters, but also monoterpene emitters and non-emitters can be found. These variations in the oak species might partly be due to their propensity for inter- and intraspecific hybridisation. This study addresses the foliar VOC production of the former hybridisation product the deciduous Quercus afares and its parents, two very distant species: the evergreen monoterpene emitter Quercus suber and the deciduous isoprene emitter Quercus canariensis. The measurements were performed in Southern France, applying two different methods. Plants were investigated in situ in the field with a portable gas exchange measuring system as well as in the laboratory on cut branches with an adapted enclosure system. Quercus afares was found to be a monoterpene emitting species. However, the monoterpene emission was lower and the composition different to that of Quercus suber. Whereas Quercus suber trees belonged to the pinene type most individuals of Quercus afares were identified to represent a limonene type. Quercus canariensis emitted besides high amounts of isoprene also linalool and (Z)-3-hexenylacetate. Emissions from Quercus suber and Quercus afares were higher in the field measurements than in the laboratory on cut branches whereas Quercus canariensis exhibited lower isoprene emissions from cut branches. The results demonstrate the need of further emission studies on a plant species level.

Welter, S.; Bracho Nuñez, A.; Staudt, M.; Kesselmeier, J.

2009-04-01

193

VOLATILE ORGANIC COMPOUND EMISSIONS FROM 46 IN-USE PASSENGER CARS  

EPA Science Inventory

Emissions from automobiles have long been considered a prime source of pollutants involved in smog formation and ozone production. The reactive potential of the species emitted has been studied extensively, and many reactivity schemes have been proposed. Most of the data on the d...

194

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

195

Anthropogenic emissions in Nigeria and implications for atmospheric ozone pollution: A view from space  

NASA Astrophysics Data System (ADS)

Nigeria has a high population density and large fossil fuel resources but very poorly managed energy infrastructure. Satellite observations of formaldehyde (HCHO) and glyoxal (CHOCHO) reveal very large sources of anthropogenic nonmethane volatile organic compounds (NMVOCs) from the Lagos megacity and oil/gas operations in the Niger Delta. This is supported by aircraft observations over Lagos and satellite observations of methane in the Niger Delta. Satellite observations of carbon monoxide (CO) and nitrogen dioxide (NO2) show large seasonal emissions from open fires in December-February (DJF). Ventilation of central Nigeria is severely restricted at that time of year, leading to very poor ozone air quality as observed from aircraft (MOZAIC) and satellite (TES). Simulations with the GEOS-Chem chemical transport model (CTM) suggest that maximum daily 8-h average (MDA8) ozone exceeds 70 ppbv over the region on a seasonal mean basis, with significant contributions from both open fires (15-20 ppbv) and fuel/industrial emissions (7-9 ppbv). The already severe ozone pollution in Nigeria could worsen in the future as a result of demographic and economic growth, although this would be offset by a decrease in open fires.

Marais, E. A.; Jacob, D. J.; Wecht, K.; Lerot, C.; Zhang, L.; Yu, K.; Kurosu, T. P.; Chance, K.; Sauvage, B.

2014-12-01

196

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

197

Levels of selected organic compounds in materials for candle production and human exposure to candle emissions  

Microsoft Academic Search

Polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) selected chlorinated pesticides, polycyclic aromatic hydrocarbons (PAH) and some volatile organic compounds (VOC) were analysed in the exhaust fumes of candles made from different waxes and finishing materials. To guarantee defined burning conditions a chamber was developed for the sampling of the exhaust fumes. Using a simple exposure model, the inhalative uptake of PCDD\\/PCDF by

C. Lau; H. Fiedler; O. Hutzinger; K.-H. Schwind; J. Hosseinpour

1997-01-01

198

[Characteristics of volatile organic compounds (VOCs) emission from electronic products processing and manufacturing factory].  

PubMed

Based on the EPA method T0-11 and 14/15 for measurement of toxic organics in air samples, fast VOCs detector, Summa canister and DNPH absorbent were used to determine the VOCs concentrations and the compositions in the ambient air of the workshops for different processes as well as the emission concentration in the exhaust gas. In all processes that involved VOCs release, concentrations of total VOCs in the workshops were 0.1-0.5 mg x m(-3), 1.5-2.5 mg x m(-3) and 20-200 mg x m(-3) for casting, cutting and painting respectively. Main compositions of VOCs in those workshops were alkanes, eneynes, aromatics, ketones, esters and ethers, totally over 20 different species. The main compositions in painting workshop were aromatics and ketones, among which the concentration of benzene was 0.02-0.34 mg x m(-3), toluene was 0.24-3.35 mg x m(-3), ethyl benzene was 0.04-1.33 mg x m(-3), p-xylene was 0.13-0.96 mg x m(-3), m-xylene was 0.02-1.18 mg x m(-3), acetone was 0.29-15.77 mg x m(-3), 2-butanone was 0.06-22.88 mg x m(-3), cyclohexene was 0.02-25.79 mg x m(-3), and methyl isobutyl ketone was 0-21.29 mg x m(-3). The VOCs emission from painting process was about 14 t x a(-1) for one single manufacturing line, and 840 t x a(-1) for the whole factory. According to the work flows and product processes, the solvent used during painting process was the main source of VOCs emission, and the exhaust gas was the main emission point. PMID:24640894

Cui, Ru; Ma, Yong-Liang

2013-12-01

199

Influence of particulate trap oxidizers on emission of mutagenic compounds by diesel automobiles.  

PubMed

Diesel exhaust particles are known to contain mutagenic and carcinogenic chemicals. The aim of this study was to determine whether, and to what extent, catalytic particulate trap oxidizers on light-duty diesel engines may reduce the emission of particle-associated mutagenic chemicals into the environment. Exhaust particles were collected from Mercedes Benz and Volkswagen diesel automobiles, equipped with or without the manufacturer's exhaust traps, while running on a chassis dynamometer under specified load conditions. Exhaust particles were collected from a dilution tunnel onto 20" X 20" Teflon-coated fiberglass filters. Mutagenesis tests of dichloromethane (DCM) extracts of the particles were conducted using the Ames Salmonella bacterial test system. The mutation rate was calculated in terms of histidine revertants per mile of travel during a set of standard test cycles. With both vehicles the traps produced an 87-92% reduction in the total amount of particulate material collected by the filters. There was no significant change in the specific mutagenic activity (revertants per microgram of DCM particle extract) with or without the traps. These studies support the notion that installation of exhaust traps which reduce particulate emission on diesel-powered vehicles will also reduce the emission of particle-associated mutagenic and carcinogenic materials into the environment. PMID:2473105

Rasmussen, R E; Devillez, G; Smith, L R

1989-06-01

200

Odor compounds in waste gas emissions from agricultural operations and food industries.  

PubMed

In the last decades, large-scale agricultural operations and food industries have increased. These operations generate numerous types of odors. The reduction of land areas available for isolation of agricultural and food processing industrial operations from the public area and the increase in sensitivity and demand of the general public for a clean and pleasant environment have forced all of these industries to control odor emissions and toxic air pollutants. To develop environmentally sound, sustainable agricultural and food industrial operations, it is necessary to integrate research that focuses on modern analytical techniques and latest sensory technology of measurement and evaluation of odor and pollution, together with a fundamental knowledge of factors that are the basic units contributing to the production of odor and pollutants. Without a clear understanding of what odor is, how to measure it, and where it originates, it will be difficult to control the odor. The present paper reviews the available information regarding odor emissions from agricultural operations and food industries by giving an overview about odor problems, odor detection and quantification, and identifying the sources and the mechanisms that contribute to the odor emissions. Finally, ways of reducing or controlling the odor problem are discussed. PMID:16129591

Rappert, S; Müller, R

2005-01-01

201

Particulate Matter Sampling and Volatile Organic Compound Removal for Characterization of Spark Ignited Direct Injection Engine Emissions  

SciTech Connect

More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion engines. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs). One method is a thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample handling methods have been implemented in an engine test cell with a spark ignited direct injection (SIDI) engine. The engine was designed for stoichiometric, homogeneous combustion. SIDI is of particular interest for improved fuel efficiency compared to other SI engines, however, the efficiency benefit comes with greater PM emissions and may therefore be subject to the proposed number based PM regulation. Another aspect of this project is to characterize PM from this engine in terms of particle number and composition.

Matthias, Nicholas; Farron, Carrie; Foster, David E.; Andrie, Michael; Krieger, Roger; Najt, Paul M.; Narayanaswamy, Kushal; Solomon, Arun S.; Zelenyuk, Alla

2012-01-01

202

Particulate Matter Sampling and Volatile Organic Compound Removal for Characterization of Spark Ignited Direct Injection Engine Emissions  

SciTech Connect

More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion engines. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs). One method is a thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample handling methods have been implemented in an engine test cell with a spark ignited direct injection (SIDI) engine. The engine was designed for stoichiometric, homogeneous combustion. SIDI is of particular interest for improved fuel efficiency compared to other SI engines, however, the efficiency benefit comes with greater PM emissions and may therefore be subject to the proposed number based PM regulation. Another aspect of this project is to characterize PM from this engine in terms of particle number and composition

Matthias, Nicholas; Farron, Carrie; Foster, David E.; Andrie, Michael; Krieger, Roger; Najt, Paul; Narayanaswamy, Kushal; Solomon, Arun S.; Zelenyuk, Alla

2012-01-01

203

Historical gaseous and primary aerosol emissions in the United States from 1990 to 2010  

NASA Astrophysics Data System (ADS)

An accurate description of emissions is crucial for model simulations to reproduce and interpret observed phenomena over extended time periods. In this study, we used an approach based on activity data to develop a consistent series of spatially resolved emissions in the United States from 1990 to 2010. The state-level anthropogenic emissions of SO2, NOx, CO, NMVOC (non-methane volatile organic compounds), NH3, PM10 and PM2.5 for a total of 49 sectors were estimated based on several long-term databases containing information about activities and emission controls. Activity data for energy-related stationary sources were derived from the State Energy Data System. Corresponding emission factors reflecting implemented emission controls were calculated back from the National Emissions Inventory (NEI) for seven years (i.e., 1990, 1995, 1996, 1999, 2001, 2002 and 2005), and constrained by the AP-42 (US EPA's Compilation of Air Pollutant Emissions Factors) dataset. Activity data for mobile sources including different types of highway vehicles and non-highway equipment were obtained from highway statistics reported by the Federal Highway Administration. The trends in emission factors for highway mobile source were informed by the 2011 National Transportation Statistics. Emissions for all non-energy-related sources were either scaled by the growth ratio of activity indicators or adjusted based on the NEI trends report. Because of the strengthened control efforts, particularly for the power sector and mobile sources, emissions of all pollutants except NH3 were reduced by half over the last two decades. The emission trends developed in this study are comparable with the NEI trend report and EDGAR (Emissions Database for Global Atmospheric Research) data, but better constrained by trends in activity data. Reductions in SO2, NOx, CO and EC (speciation of PM2.5 by SMOKE, Sparse Matrix Operator Kernel Emissions) emissions agree well with the observed changes in ambient SO2, NO2, CO and EC concentrations, suggesting that the various controls on emissions implemented over the last two decades are well represented in the emission inventories developed in this study. These inventories were processed by SMOKE and are now ready to be used for regional chemistry transport model simulations over the 1990-2010 period.

Xing, J.; Pleim, J.; Mathur, R.; Pouliot, G.; Hogrefe, C.; Gan, C.-M.; Wei, C.

2013-08-01

204

Ozone reactivity of biogenic volatile organic compound (BVOC) emissions during the Southeast Oxidant and Aerosol Study (SOAS)  

NASA Astrophysics Data System (ADS)

Recent studies on atmospheric chemistry in the forest environment showed that the total reactivity by biogenic volatile organic compound (BVOC) emission is still not well understood. During summer 2013, an intensive field campaign (Southeast Oxidant and Aerosol Study - SOAS) took place in Alabama, U.S.A. In this study, an ozone reactivity measurement system (ORMS) was deployed for the direct determination of the reactivity of foliage emissions. The ORMS is a newly developed measurement approach, in which a known amount of ozone is added to the ozone-free air sample stream, with the ORMS measuring ozone concentration difference between before and after a glass flask flow tube reaction vessel (2-3 minutes of residence time). Emissions were also collected onto adsorbent cartridges to investigate the discrepancy between total ozone reactivity observation and reactivity calculated from identified BVOC. Leaf and canopy level experiments were conducted by deploying branch enclosures on the three dominant tree species at the site (i.e. liquidambar, white oak, loblolly pine) and by sampling ambient air above the forest canopy. For the branch enclosure experiments, BVOC emissions were sampled from a 70 L Teflon bag enclosure, purged with air scrubbed for ozone, nitrogen oxides. Each branch experiment was performed for 3-5 days to collect at least two full diurnal cycle data. In addition, BVOCs were sampled using glass tube cartridges for 2 hours during daytime and 3 - 4 hours at night. During the last week of campaign, the inlet for the ORMS was installed on the top of scaffolding tower (~30m height). The ozone loss in the reactor showed distinct diurnal cycle for all three tree species investigated, and ozone reactivity followed patterns of temperature and light intensity.

Park, J.; Guenther, A. B.; Helmig, D.

2013-12-01

205

Serratia odorifera: analysis of volatile emission and biological impact of volatile compounds on Arabidopsis thaliana.  

PubMed

Bacteria emit a wealth of volatiles. The combination of coupled gas chromatography/mass spectrometry (GC/MS) and proton-transfer-reaction mass spectrometry (PTR-MS) analyses provided a most comprehensive profile of volatiles of the rhizobacterium Serratia odorifera 4Rx13. An array of compounds, highly dominated by sodorifen (approximately 50%), a bicyclic oligomethyl octadiene, could be detected. Other volatiles included components of the biogeochemical sulfur cycle such as dimethyl disulfide (DMDS), dimethyl trisulfide and methanethiol, terpenoids, 2-phenylethanol, and other aromatic compounds. The composition of the bouquet of S. odorifera did not change significantly during the different growth intervals. At the beginning of the stationary phase, 60 ?g of volatiles per 24 h and 60 easily detectable components were released. Ammonia was also released by S. odorifera, while ethylene, nitric oxide (NO) and hydrogen cyanide (HCN) could not be detected. Dual culture assays proved that 20 ?mol DMDS and 2.5 ?mol ammonia, individually applied, represent the IC(50) concentrations that cause negative effects on Arabidopsis thaliana. PMID:20717666

Kai, Marco; Crespo, Elena; Cristescu, Simona M; Harren, Frans J M; Francke, Wittko; Piechulla, Birgit

2010-10-01

206

Reduction of dioxin-like compound emissions from a Waelz plant with adsorbent injection and a dual baghouse filter system.  

PubMed

Previous study indicates that the polychlorinated dibenzo-p-dioxin and -dibenzofurans (PCDD/F) concentration measured in the stack gas of the Waelz plant investigated reached 194 ng-TEQ/(N m3) (TEQ = toxic equivalence), due to the relatively high potential of PCDD/F formation and a low PCDD/F removal efficiency (<70%) achieved with the baghouse filter (BF). In September 2006, the Taiwan government setthe PCDD/F emission limit for existing Waelz plants as 1.0 ng-I-TEQO/(N m3). The retrofit technology for reducing PCDD/F emissions from the existing Waelz plant was evaluated at the same time. Carbon-type adsorbent injection technology was adopted in early 2006 to reduce the emission of dioxin-like compounds at the Waelz plant investigated. Flue gases and ambient air samplings were conducted during the two stages of retrofit to evaluate the removal efficiency of dioxin-like compounds at the Waelz plant investigated. At stage 1, by applying adsorbent injection + single baghouse filter (SBF), the PCDD/F and polychlorinated biphenyl (PCB) concentrations measured in the stack gas at the Waelz plant were 4.62 ng-TEQ/(N m3) and 0.08 ng-TEQ(WHO)/(N m3) (TEQ(WHO) = World Health Organization TEQ), respectively, as the adsorbent injection rate was controlled at 40 kg/h (or 540 mg/ (N m3)). At stage 2, the PCDD/F and PCB concentration measured at stack gas, achieved with adsorbent injection + dual baghouse filter (DBF) system, were further reduced to 0.235 + 0.04 ng-I-TEQ/(N m3) (I-TEQ = International TEQ) and 0.004 + 0.002 ng-TEQ(WHO)/(N m3) with the adsorbent injection rate at 16 kg/h (or 215 mg/(N m3)). In the meantime, the atmospheric PCDD/F concentrations measured in the vicinity area of the Waelz plant were greatly reduced from 568-1465 to 48.9-130 fg-I-TEQ/m3. Higher removal efficiency (>99.8%) achieved at a lower adsorbent injection rate (16 kg/h) of the adsorbent injection + DBF system also significantly reduced the total PCDD/-F and PCB emission flows (per kg of electric arc furnace dust treated) to 1925 ng-I-TEQ and 30.5 ng-TEQ(WHO), respectively. PMID:18409645

Chi, Kai Hsien; Chang, Shu Hao; Chang, Moo Been

2008-03-15

207

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

208

Development and Application of a Fast Chromatography Technique for Analysis of Biogenic Volatile Organic Compounds in Plant Emissions  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOCs) emitted from vegetation constitute the largest fraction (>90 %) of total global non-methane VOC supplied to the atmosphere, yet the chemical complexity of these emissions means that achieving comprehensive measurements of BVOCs, and in particular the less volatile terpenes, is not straightforward. As such, there is still significant uncertainty associated with the contribution of BVOCs to the tropospheric oxidation budget, and to atmospheric secondary organic aerosol (SOA) formation. The rate of BVOC emission from vegetation is regulated by environmental conditions such as light intensity and temperature, and thus can be highly variable, necessitating high time-resolution BVOC measurements. In addition, the numerous monoterpene and sesquiterpene isomers, which are indistinguishable by some analytical techniques, have greatly varying lifetimes with respect to atmospheric oxidants, and as such quantification of each individual isomer is fundamental to achieving a comprehensive characterisation of the impact of BVOCs upon the atmospheric oxidation capacity. However, established measurement techniques for these trace gases typically offer a trade-off between sample frequency and the level of speciation; detailed information regarding chemical composition may be obtained, but with reduced time resolution, or vice versa. We have developed a Fast-GC-FID technique for quantification of a range of monoterpene, sesquiterpene and oxygenated C10 BVOC isomers, which retains the separation capability of conventional gas chromatography, yet offers considerably improved sample frequency. Development of this system is ongoing, but currently a 20 m x 0.18 mm i.d resistively heated metal column is employed to achieve chromatographic separation of thirteen C10-C15 BVOCs, within a total cycle time of ~15 minutes. We present the instrument specifications and analytical capability, together with the first application of this Fast-GC technique for BVOC analysis, monitoring BVOC emissions from white spruce (Picea glauca) during plant chamber studies.

Jones, C. E.; Kato, S.; Nakashima, Y.; Yamazakii, S.; Kajii, Y. J.

2011-12-01

209

Cancer risks from soil emissions of volatile organic compounds at the Lawrence Livermore National Laboratory  

SciTech Connect

The emission isolation flux chamber (EIFC) methodology was applied to Superfund investigations at the Lawrence Livermore National Laboratory Site 300 to determine if on-site workers were exposed to VOCs volatilizing from the subsurface and what, if any, health risks could be attributed to the inhalation of the VOCs volatilizing from the subsurface. During July and August of 1996, twenty, eighteen, and twenty six VOC soil vapor flux samples were collected in the Building 830, 832, and 854 areas, respectively using EIFCS. The VOC concentrations in the vapor samples were used to calculate soil flux rates which were used as input into an air dispersion model to calculate ambient air exposure-point concentrations. The exposure-point concentrations were compared to EPA Region IX Preliminary Remediation Goals (PRGs). Buildings 830 and 832 exposure-point concentrations were less then the PRGs therefore no cancer risks were calculated. The cancer risks for Building 854 ranged from 1.6 x 10{sup -7} to 2.1 x 10{sup -6}. The resultant inhalation cancer risks were all within the acceptable range, implying that on-site workers were not exposed to VOC vapors volatilizing from the subsurface soil that could have significant cancer risks. Therefore remediation in these areas would not be necessary.

Dibley, V. R., LLNL

1998-02-01

210

Automobile commuter exposures to volatile organic compounds: Emissions, malfunctions, and policy  

SciTech Connect

The general population is exposed to the Volatile Organic Compounds (VOCs) n-hexane, 3-methylpentane, benzene, toluene, isooctane, xylenes, ethylbenzene, and 1,2,4-trimethylbenzene, and to carbon monoxide (CO), and formaldehyde in many microenvironments, including the passenger compartments of automobiles. This study determined the in-vehicle exposures to the above gasoline derived VOCs, carbon monoxide, and formaldehyde for automobile commuters during a suburban New Jersey and a New Jersey/New York commute. Measurements of VOC concentrations were determined within the passenger compartment of idling automobiles and along two commuting routes. Little difference in concentrations was seen between the two different interior ventilation extremes (windows open and vents on, windows closed and vents off) for properly functioning vehicles. However, exposures to all VOCs increased substantially when malfunctions occurred with the carburetor, electric choke, and fuel distribution system of one of the vehicles. These increases were largest when the vehicle`s windows were closed and ventilation system was off. Exposures to VOCs were lowest in the suburban commute, slightly higher on the New Jersey Turnpike, and highest in transit through the Lincoln Tunnel. The national daily average in-vehicle duration (93.2 minutes, or 6.5% of the day) and median in-vehicle benzene concentrations on the suburban and urban loops accounted for 9.3% and 10.3% of the total daily benzene exposures, respectively. Exposures nearly tripled for in-vehicle concentrations in the 90th percentile. Excess cancer risks from benzene exposure exceeded 1/10{sup 5} for benzene exposures above the 90th percentile. Lifetime cancer risks for formaldehyde exposures were below 1/10{sup 6}. Maximum n-hexane exposures were below the critical dose value for adverse effects to the central nervous system.

Lawryk, N.J.

1994-12-31

211

Non-methane volatile organic compounds predict odor emitted from five tunnel ventilated broiler sheds.  

PubMed

Non-methane volatile organic compounds (NMVOCs) emitted from mechanically ventilated poultry sheds in similar stages (32-36 d) of broiler production were measured by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS), then identified using parallel factor analysis (PARAFAC2) and the NIST11 database. Calibration models predicting odor measured by dilution olfactometry from NMVOC concentrations via orthogonal projection to latent structures (O-PLS) made good predictions (Rp(2)=0.83-0.87, RMSEp=137-175OU) using one to eight NMVOCs with either one or two latent variables representing odor concentration and character, respectively. Similar changes in odorant composition were observed in each sampling campaign, with samples collected early in the day more odorous and more sulfurous than samples collected later in the day. High litter moisture favored sulfur-containing odorants over alcohols, aldehydes and ketones but had little bearing on perceived odor, whereas high bird density favored alcohols, aldehydes and ketones over sulfur-containing odorants. Eight VOCs that were important predictors of odor across all sheds in order of decreasing importance were dimethyl sulfide (DMS), dimethyl trisulfide (DMTS), 2-3 butanedione, 3-methyl-butanal, 1-butanol, 3-methyl-1-butanol, acetoin, and 2-butanone. Four additional NMVOCs also influenced perceived odor although less predictably; these were n-hexane, 2-butanol, dimethyl disulfide (DMDS), and 1-octen-3-ol. All of the odorants are associated with microbial or fungal activity in the litter and manure, except n-hexane, which may originate from hexane-extracted soybean meal in the chicken feed. The organosulfides measured in this study may have arisen from the field sites as well as from the degradation of thiols captured on sorbent tubes during analysis by TD-GC/MS. PMID:24188627

Murphy, Kathleen R; Parcsi, Gavin; Stuetz, Richard M

2014-01-01

212

The tropical forest and fire emissions experiment: Emission, chemistry, and transport of biogenic volatile organic compounds in the lower atmosphere over Amazonia  

NASA Astrophysics Data System (ADS)

Airborne and ground-based mixing ratio and flux measurements using eddy covariance (EC) and for the first time the mixed layer gradient (MLG) and mixed layer variance (MLV) techniques are used to assess the impact of isoprene and monoterpene emissions on atmospheric chemistry in the Amazon basin. Average noon isoprene (7.8 ± 2.3 mg/m2/h) and monoterpene fluxes (1.2 ± 0.5 mg/m2/h) compared well between ground and airborne measurements and are higher than fluxes estimated in this region during other seasons. The biogenic emission model, Model of Emissions of Gases and Aerosols from Nature (MEGAN), estimates fluxes that are within the model and measurement uncertainty and can describe the large observed variations associated with land-use change in the region north-west of Manaus. Isoprene and monoterpenes accounted for ˜75% of the total OH reactivity in this region and are important volatile organic compounds (VOCs) for modeling atmospheric chemistry in Amazonia. The presence of fair weather clouds (cumulus humilis) had an important impact on the vertical distribution and chemistry of VOCs through the planetary boundary layer (PBL), the cloud layer, and the free troposphere (FT). Entrainment velocities between 10:00 and 11:30 local time (LT) are calculated to be on the order of 8-10 cm/s. The ratio of methyl-vinyl-ketone (MVK) and methacrolein (MAC) (unique oxidation products of isoprene chemistry) with respect to isoprene showed a pronounced increase in the cloud layer due to entrainment and an increased oxidative capacity in broken cloud decks. A decrease of the ratio in the lower free troposphere suggests cloud venting through activated clouds. OH modeled in the planetary boundary layer using a photochemical box model is much lower than OH calculated from a mixed layer budget approach. An ambient reactive sesquiterpene mixing ratio of 1% of isoprene would be sufficient to explain most of this discrepancy. Increased OH production due to increased photolysis in the cloud layer balances the low OH values modeled for the planetary boundary layer. The intensity of segregation (Is) of isoprene and OH, defined as a relative reduction of the reaction rate constant due to incomplete mixing, is found to be significant: up to 39 ± 7% in the ˜800-m-deep cloud layer. The effective reaction rate between isoprene and OH can therefore vary significantly in certain parts of the lower atmosphere.

Karl, Thomas; Guenther, Alex; Yokelson, Robert J.; Greenberg, Jim; Potosnak, Mark; Blake, Donald R.; Artaxo, Paulo

2007-09-01

213

Emissions of terpenoids, benzenoids, and other biogenic gas-phase organic compounds from agricultural crops and their potential implications for air quality  

NASA Astrophysics Data System (ADS)

Agriculture comprises a substantial, and increasing, fraction of land use in many regions of the world. Emissions from agricultural vegetation and other biogenic and anthropogenic sources react in the atmosphere to produce ozone and secondary organic aerosol, which comprises a substantial fraction of particulate matter (PM2.5). Using data from three measurement campaigns, we examine the magnitude and composition of reactive gas-phase organic carbon emissions from agricultural crops and their potential to impact regional air quality relative to anthropogenic emissions from motor vehicles in California's San Joaquin Valley, which is out of compliance with state and federal standards for tropospheric ozone PM2.5. Emission rates for a suite of terpenoid compounds were measured in a greenhouse for 25 representative crops from California in 2008. Ambient measurements of terpenoids and other biogenic compounds in the volatile and intermediate-volatility organic compound ranges were made in the urban area of Bakersfield and over an orange orchard in a rural area of the San Joaquin Valley during two 2010 seasons: summer and spring flowering. We combined measurements from the orchard site with ozone modeling methods to assess the net effect of the orange trees on regional ozone. When accounting for both emissions of reactive precursors and the deposition of ozone to the orchard, the orange trees are a net source of ozone in the springtime during flowering, and relatively neutral for most of the summer until the fall, when it becomes a sink. Flowering was a major emission event and caused a large increase in emissions including a suite of compounds that had not been measured in the atmosphere before. Such biogenic emission events need to be better parameterized in models as they have significant potential to impact regional air quality since emissions increase by several factors to over an order of magnitude. In regions like the San Joaquin Valley, the mass of biogenic emissions from agricultural crops during the summer (without flowering) and the potential ozone and secondary organic aerosol formation from these emissions are on the same order as anthropogenic emissions from motor vehicles and must be considered in air quality models and secondary pollution control strategies.

Gentner, D. R.; Ormeño, E.; Fares, S.; Ford, T. B.; Weber, R.; Park, J.-H.; Brioude, J.; Angevine, W. M.; Karlik, J. F.; Goldstein, A. H.

2014-06-01

214

From emissions to ambient mixing ratios: on-line seasonal field measurements of volatile organic compounds over a Norway spruce dominated forest in central Germany  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (BVOC) are substantial contributors to atmospheric chemistry and physics and demonstrate the close relationship between biosphere and atmosphere. Their emission rates are highly sensitive to meteorological and environmental changes with concomitant impacts on atmospheric chemistry. We have investigated seasonal isoprenoid and oxygenated VOC (oxVOC) fluxes from a Norway spruce (Picea abies) tree in Central Germany and explored the emission responses under various atmospheric conditions. Emission rates were quantified by using dynamic branch enclosure and Proton Transfer Reaction-Mass Spectrometry (PTR-MS) techniques. Additionally, ambient mixing ratios were derived through application of a new box model treatment on the dynamic chamber measurements. These are compared in terms of abundance and origin with the corresponding emissions. Isoprenoids govern the BVOC emissions from Norway spruce, with monoterpenes and sesquiterpenes accounting for 50.8 ± 7.2% and 19.8 ± 8.1% respectively of the total emissions. Normalizing the VOC emission rates, we have observed a trend of reduction of carbon containing emissions from April to November, with an enhancement of oxVOC. Highest emission rates were observed in June for all measured species, with the exception of sesquiterpenes that were emitted most strongly in April. We exploit the wide range of conditions experienced at the site to filter the dataset with a combination of temperature, ozone and absolute humidity values in order to derive the emission potential and temperature dependency development for the major chemical species investigated. A profound reduction of monoterpene emission potential (E30) and temperature dependency (?) was found under low temperature regimes, combined with low ozone levels (E30MT, LTLO3=56 ± 9.1 ng g(dw)-1 h-1, ?MT,LTLO3=0.03±0.01 K-1) while a combination of both stresses was found to alter their emissions responses with respect to temperature substantially (E30MT,HTHO3=1420.1 ± 191.4 ng g(dw)-1 h-1, ?MT,HTHO3=0.15 ± 0.02 K-1). Moreover, we have explored compound relationships under different atmospheric condition sets, addressing possible co-occurrence of emissions under specific conditions. Finally, we evaluate the temperature dependent algorithm that seems to describe the temperature dependent emissions. Highest emission deviations were observed for monoterpenes and these emission fluctuations were attributed to a fraction which is triggered by an additional light dependency.

Bourtsoukidis, E.; Williams, J.; Kesselmeier, J.; Jacobi, S.; Bonn, B.

2013-11-01

215

Few long-term effects of simulated climate change on volatile organic compound emissions and leaf chemistry of three subarctic dwarf shrubs  

Microsoft Academic Search

Climate change is exposing arctic ecosystems to higher temperature, increased nutrient availability and shading due to the increasing cloud cover and the expanding forests. In this work, we assessed how these factors affect the emissions of biogenic volatile organic compounds (BVOCs) from three subarctic dwarf shrub species in a field experiment after 18 treatment years. Of the studied species the

Riikka Rinnan; A. Rinnan; Patrick Faubert; Päivi Tiiva; Jarmo K. Holopainen; Anders Michelsen

2011-01-01

216

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...

217

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...

218

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...

219

Emissions of organo-metal compounds via the leachate and gas pathway from two differently pre-treated municipal waste materials - A landfill reactor study  

SciTech Connect

Due to their broad industrial production and use as PVC-stabilisers, agro-chemicals and anti-fouling agents, organo-metal compounds are widely distributed throughout the terrestrial and marine biogeosphere. Here, we focused on the emission dynamics of various organo-metal compounds (e.g., di,- tri-, tetra-methyl tin, di-methyl mercury, tetra-methyl lead) from two different kinds of pre-treated mass waste, namely mechanically-biologically pre-treated municipal solid waste (MBP MSW) and municipal waste incineration ash (MWIA). In landfill simulation reactors, the emission of the organo-metal compounds via the leachate and gas pathway was observed over a period of 5 months simulating different environmental conditions (anaerobic with underlying soil layer/aerated/anaerobic). Both waste materials differ significantly in their initial amounts of organo-metal compounds and their environmental behaviour with regard to the accumulation and depletion rates within the solid material during incubation. For tri-methyl tin, the highest release rates in leachates were found in the incineration ash treatments, where anaerobic conditions in combination with underlying soil material significantly promoted its formation. Concerning the gas pathway, anaerobic conditions considerably favour the emission of organo-metal compounds (tetra-methyl tin, di-methyl mercury, tetra-methyl lead) in both the MBP material and especially in the incineration ash.

Michalzik, B. [Institute of Geography, Georg-August University Goettingen, Unit of Landscape Ecology, Goldschmidtstrasse 5, 37073 Goettingen (Germany)], E-mail: bmichal@gwdg.de; Ilgen, G.; Hertel, F. [Bayreuth Institute of Terrestrial Ecosystem Research (BITOEK/BayCEER), Central Laboratory Unit, University of Bayreuth, Dr. Hans- Frisch-Strasse 1-3, 95448 Bayreuth (Germany); Hantsch, S.; Bilitewski, B. [Institute for Waste Management and Contaminated Site Treatment, Dresden University of Technology, Pratzschwitzer Strasse 15, 01796 Pirna (Germany)

2007-07-01

220

Air pollutant emissions from on-road vehicles in China, 1999-2011.  

PubMed

The on-road vehicular emission in China from 1999 to 2011 was estimated, based on the emission factors of vehicles with different emission standards calculated by the COPERT model. The CO, NMVOC, NOX, BC and OC emissions changed from 19.7 Tg, 4.4 Tg, 2.3 Tg, 47.1 Gg and 74.4 Gg in 1999 to 32.7 Tg, 4.1 Tg, 7.6 Tg, 177.6 Gg and 101.5 Gg in 2011, respectively. The general trend for CO, NOX and BC was increasing, while the tendency for NMVOC and OC was firstly increase before 2002 and then decrease from 2003. The spatial analysis results showed that high emissions occurred in developed provinces (Guangdong, Shandong, Hebei, Jiangsu and Henan). The correlation between vehicular emissions and GDP were further investigated and good linear correlation was found. The not-obvious change of the inter-annual (1999-2011) fitted straight line slope and the sustained increasing emissions for NOX and BC suggested that the challenge of mitigating vehicular NOX and BC emissions is severe in China. The contribution from different vehicle types was also analyzed. Passenger car (PC) and motorcycle (MC) was the main contributor to the CO and NMVOC emissions. However, the contribution ratio of MC was decreasing from 36.6% and 68.8% in 1999 to 15.7% and 25.7% in 2011. Heavy duty truck (HDT) was the dominant contributor to NOX, BC and OC, with proportions of 58.9%, 57.6% and 52.8% in 2011, respectively. In addition, the uncertainty of the estimated emissions was also assessed based on the Monte Carlo simulation. PMID:25051424

Lang, Jianlei; Cheng, Shuiyuan; Zhou, Ying; Zhang, Yonglin; Wang, Gang

2014-10-15

221

Emission of organic compounds from mould and core binders used for casting iron, aluminium and bronze in sand moulds.  

PubMed

Emissions from mould and core sand binders commonly used in the foundry industry have been investigated. Degradation of three different types of binders was investigated: Furfuryl alcohol (FA), phenolic urethane (PU) and resol-CO2 (RC). In each group of binders, at least two different binder compositions were tested. A test method that provides uniform test conditions is described. The method can be used as a general test method to analyse off gases from binders. Moulds, containing a standard size casting, were produced and the amount and type of organic compounds, resulting from thermal degradation of binders, was monitored when cast iron, bronze and aluminium was poured in the moulds. Binder degradation was measured by collecting off gases in a specially designed ventilation hood at a constant flow rate. Samples were taken from the ventilation system and analysed for hydrocarbons and CO content. It is shown how off-gases vary with time after pouring and shake out. Also the composition of off-gases is analysed and shown. It is further shown how the composition of off-gasses varies between different types of binders and with varying composition of the binders as well as function of the thermal load on the moulding sand. PMID:20954042

Tiedje, Niels; Crepaz, Rudolf; Eggert, Torben; Bey, Niki

2010-12-01

222

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

223

Quantifying Marine Emissions of Biogenic Volatile Organic Compounds Using Laboratory Measurements of Plankton Monocultures and Field Samples  

NASA Astrophysics Data System (ADS)

Marine biogenic volatile organic compounds (BVOCs) have been suggested to contribute significant portion of the organic carbon present in ocean atmosphere. In this study emission rates of 40 different hydrocarbons are quantified for lab-grown non-axenic phytoplankton monocultures and ambient samples from the Pamlico-Neuse Estuary, NC. The outcome of environmental conditions on production of BVOCs was examined for different light and temperature conditions. These different regimes are considered proxies for physiological stress-induced effects observed in natural ecosystems. The samples were incubated in a climate controlled room; they were then transferred to smaller volumes (200 ml) for analysis. BVOCs accumulated in the water and headspace above the water were measured by bubbling hydrocarbon-free gas mixture through the sample and passing the gas stream through a gas chromatography/mass spectrometry system equipped with a sample pre-concentrator. Inside the pre-concentrator, the compounds were trapped on a sorbent material, heated, and flushed into the GC-MS column. The pre-concentrator/GC-MS system gave at least 1000 times magnification of the sample concentrations, allowing detection of low ppt levels of hydrocarbons. Here we report results for lab-grown diatoms Thalassiosira weissflogii and Thalassiosira pseudonana, prymnesiophyte Pleurochrysis carterae, and dinoflagellates Karina brevis and Procentrum minimum, as well as field samples. To make results widely usable, all the emissions are normalized to Chlorophyll-a (Chl-a) concentration and cell counts. Our results show that diatoms had the highest isoprene production rate of 2.8 ?mol (g Chl-a)-1 h-1 with ranges between 1.4 and 3.6 ?mol (g Chl-a)-1 h-1 at light levels between 90 and 900 ?E m-2 s-1, respectively. The prymnesiophyte and dinoflagellate species had isoprene production rates of 1.3±0.4 ?mol (g Chl-a)-1 h-1 with a similar light dependency as diatoms. Field samples had comparable isoprene production rate of 3.5 ?mol (g Chl-a)-1 h-1 with ranges between 0.6 and 4.1 ?mol (g Chl-a)-1 h-1 for similar light levels and temperatures between 18 to 30°C. Three monoterpenes detected were ?-pinene, camphene, and d-limonene. Diatoms had the highest ?-pinene and d-limonene production rates of 0.045 ?mol (g Chl-a)-1 h-1 and 0.015 ?mol (g Chl-a)-1 h-1, respectively. The prymnesiophyte species had the highest camphene production of 0.021 ?mol (g Chl-a)-1 h-1. Production rates of d-limonene and camphene did not show a well-defined light dependency, but both isoprene and ?-pinene showed an increase in terpene production with increasing light intensities. Field samples show ?-pinene, d-limonene, and camphene production rates of 0.05 ?mol (g Chl-a)-1 h-1, 0.02 ?mol (g Chl-a)-1 h-1 and 0.018 ?mol (g Chl-a)-1 h-1, respectively. Field samples acclimated at 26°C had the highest terpene production rates. This study tabulates a large number of BVOC emission rates for various phytoplankton species under diverse environmental conditions.

Sabolis, A. W.; Meskhidze, N.; Kamykowski, D.; Reed, R. E.

2010-12-01

224

Improving the accuracy of carbon-to-hydrogen ratio determination for P, N, S, O, Cl, and Br-containing organic compounds using atomic emission detection.  

PubMed

The objective of this work was to investigate the dependence of atomic emission detector C and H response on microwave-induced plasma conditions and to improve the accuracy of carbon-to-hydrogen ratio determination for trialkylphosphates, herbicides, chlorophenols, and sulfur-containing organic compounds. Compounds which differed structurally from the analytes were used as reference compounds. It was found that when the oxygen concentration in the helium was the maximum for the instrument (9%) relative errors in carbon-to-hydrogen ratio determination were 3-8%, irrespective of analyte and reference compound structure, whereas when working in the mode of operation recommended by the manufacturer of the instrument (1.5% oxygen in helium) the respective errors were 10-20% or higher. This improvement in the accuracy of carbon-to-hydrogen ratio determination was accompanied by a factor of ten decrease in sensitivity. PMID:15688154

Chernetsova, Elena S; Revelsky, Alexander I; Durst, Dupont; Sobolevsky, Tim G; Revelsky, Igor A

2005-05-01

225

Implementation and evaluation of a comprehensive emission model for Europe  

NASA Astrophysics Data System (ADS)

Crucial input data sets for Chemical Transport Models (CTM) are the meteorological fields and the emissions data. While there are several publicly available meteorological models, the situation for European emission models is still different. European emissions data either lack spatial and temporal resolution, only cover specific countries or are proprietary and not free to use. In this work the US EPA emission model SMOKE (Sparse Matrix Operator Kernel Emissions) has been successfully adapted and partially extended to create European emissions input for CTMs. The modified version of the SMOKE emission model (SMOKE/E) uses official and publicly available data sets and statistics to create emissions of CO, NOx, SO2, NH3, PM2.5, PM10, NMVOC. Currently it supports VOC splits for several photochemical mechanisms, namely CB4, CB5 and RADM2. PM2.5 is split into elemental carbon, organic carbon, sulfate, nitrate and other particles. Additionally emissions of benzo[a]pyrene (BaP) have been modelled with SMOKE Europe. The temporal resolution of the emissions is one hour, the horizontal resolution is up to 1x1 km². SMOKE/E also implements plume in grid calculations for vertical distribution of point sources. The vertical resolution is infinitely variable and is implemented in the form of pressure levels. The area covered by the emission model at this point is Europe and it's surrounding countries, including north Africa and parts of Asia. Thus far SMOKE Europe has been used to create European emissions on a 54x54km² grid covering the whole of Europe and a 18x18km² nested grid over the North and Baltic Sea for the years 1990-2006. The currently implemented datasets allow for the calculation of emissions between 1970-2010. Besides this future emissions scenarios for the timespan 2010-2020 are being calculated using the EMEP projections. The created emissions have been statistically compared to the gridded EMEP emissions as well as to data from other emission models for the base years 2000 and 2001. The 54x54km² emissions data for 2000 were used as input for the CMAQ4.6 CTM and the calculated air concentrations were compared to EMEP measurements in Europe. Statistical comparison of Ozone and three particulate species (NH4,NO3,SO4) showed that SMOKE/E performs very good under the tested circumstances. O3 : (NMB 0.71) (SD 0.68) (F2 0.83) (CORR 0.55) using 48 Stations (hourly) NH4: (NMB 0.25) (SD 1.01) (F2 0.55) (CORR 0.53) using 8 Stations (daily) NO3: (NMB 0.42) (SD 0.60) (F2 0.40) (CORR 0.45) using 7 Stations (daily) SO4: (NMB 0.34) (SD 0.84) (F2 0.65) (CORR 0.55) using 21 Stations (daily) Abbreviations: Normalized Mean Bias (NMB), Standard Deviation (SD), Factor of 2 (F2), Correlation (CORR). The calculated air concentrations were compared with CMAQ runs using two purchased emissions datasets. It could be shown that the modified SMOKE model produces results comparable to those of commonly used European emissions data sets. For the future it is planed to implement emissions of heavy metals and polyfluorinated compounds into the SMOKE Europe model.

Bieser, Johannes; Aulinger, Armin; Matthias, Volker; Quante, Markus

2010-05-01

226

Estimation of biogenic volatile organic compound (BVOC) emissions from the terrestrial ecosystem in China using real-time remote sensing data  

NASA Astrophysics Data System (ADS)

Because of the high emission intensity and reactivity, biogenic volatile organic compounds (BVOCs) play a significant role in the terrestrial ecosystems, human health, secondary pollution, global climate change and the global carbon cycle. Past estimations of BVOC emissions in China were based on outdated algorithms and limited meteorological data, and there have been significant inconsistences between the land surface parameters of dynamic models and those of BVOC estimation models, leading to large inaccuracies in the estimated results. To refine BVOC emission estimations for China and to further explore the role of BVOCs in atmospheric chemical processes, we used the latest algorithms of MEGAN (Model of Emissions of Gases and Aerosols from Nature) with MM5 (the Fifth-Generation Mesoscale Model) providing highly resolved meteorological data, to estimate the biogenic emissions of isoprene (C5H8) and seven monoterpene species (C10H16) in 2006. Real-time MODIS (Moderate Resolution Imaging Spectroradiometer) data were introduced to update the land surface parameters and improve the simulation performance of MM5, and to modify the influence of leaf area index (LAI) and leaf age deviation from standard conditions. In this study, the annual BVOC emissions for the whole country totaled 12.97 Tg C, a relevant value much lower than that given in global estimations but higher than the past estimations in China. Therein, the most important individual contributor was isoprene (9.36 Tg C), followed by ?-pinene (1.24 Tg C yr-1) and ?-pinene (0.84 Tg C yr-1). Due to the considerable regional disparity in plant distributions and meteorological conditions across China, BVOC emissions presented significant spatial-temporal variations. Spatially, isoprene emission was concentrated in South China, which is covered by large areas of broadleaf forests and shrubs. On the other hand, Southeast China was the top-ranking contributor of monoterpenes, in which the dominant vegetation genera consist of evergreen coniferous forests (mainly Pinus massoniana). Temporally, BVOC emissions primarily occurred in July and August during periods of high temperatures, high solar radiation and dense plant cover, with daily emissions peaking at about 13:00~14:00 hours (Beijing Time, BJT) and reaching their lowest values at night. Additionally, emissions of volatile organic compounds (VOCs) of biogenic origin (14.7 Tg yr-1) were approximately one-third less than anthropogenic emissions (23.2 Tg yr-1) and showed distinct spatial distributions. We present a reasonable estimation of BVOC emissions, which provides important information for further exploration of the role of BVOCs in atmospheric processes.

Li, M.; Huang, X.; Li, J.; Song, Y.

2012-04-01

227

Particulate Matter Sampling and Volatile Organic Compound Removal for Characterization of Spark Ignited Direct Injection Engine Emissions  

SciTech Connect

More stringent emissions regulations are continually being proposed to mitigate adverse human health and environmental impacts of internal combustion. With that in mind, it has been proposed that vehicular particulate matter (PM) emissions should be regulated based on particle number in addition to particle mass. One aspect of this project is to study different sample handling methods for number based aerosol measurements, specifically, two different methods for removing volatile organic compounds (VOCs) from an aerosol sample. One method is a Dekati Thermodenuder (TD) and the other is an evaporative chamber/diluter (EvCh). These sample handling methods have been implemented for this project in an engine test cell built around a direct injection spark ignited (DISI) engine. The engine was designed for stoichiometric, homogeneous combustion. Direct injection is of particular interest for improved fuel efficiency but this comes with the production of a significant amount of (PM) and may therefore be subject to the proposed number based regulation. Another aspect of this project is to characterize PM from this engine in terms of particle number and composition. The first interesting observation is that PM number distributions, acquired using a TSI SMPS, have a large accumulation mode (30-294 nm) but a very small nuclei mode (8-30 nm). This is understood to represent a lack of condensation particles meaning that neither the exhaust conditions nor the sample handling conditions are conducive to condensation. This lack of nuclei mode does not, however, represent a lack of VOCs in the sample. It has been observed, using mass spectral analysis (limited to PM>50 nm), that PM from the DISI engine has approximately 40% organic content through varying operating conditions. This begs the question of how effective different sample handling methods are at removing these VOCs. For one specific operating condition, called Cold Start, the un-treated PM was 40% organic. The TD reduced this by 7% while the EvCh reduced it by 13%. For other operating conditions, PM treated for volatile removal actually exhibited an increase in organic fraction on the order of 5%. This addition appears to be sensitive to the gaseous hydrocarbon concentrations in the exhaust although a precise correlation has not yet been derived. It has been concluded that VOCs are tightly bound to the PM carbon core and thus are not effectively removed by either treatment method.

Matthias, Nick; Farron, Carrie; Foster, David E.; Andrie, Mike; Krieger, Roger; Najt, Paul; Narayanaswamy, Kushal; Solomon, Arun; Zelenyuk, Alla

2012-01-01

228

Using IASI and MIPAS in combination to characterise CO and other volatile organic compound emissions from fires  

NASA Astrophysics Data System (ADS)

Short-lived species emitted from wildfires, such as carbon monoxide (CO) and volatile organic compounds (VOCs), carry a lot of information on atmospheric processes relating to chemistry, convection and emission. These disruptive events are indirectly a climatological feature of the Earth's atmosphere and its climate response and occur at sufficient frequency to make studying and understanding biomass plume chemistry vital. Accurate measurement of trace gases from these events will also aid improvements in climate/chemistry models. In this study, we utilise IASI, MIPAS and ACE data to derive wildfire emissions of VOCs, in the context of two periods; the early 2009 Black Saturday fires and the BORTAS campaign fires. Using the complementary viewing angles of IASI (nadir) and MIPAS/ACE (limb), results will be shown which illustrate observations of aged plume composition, chemistry, distribution and area along with information about vertical distribution. The Black Saturday fires were a particularly severe event over South-Eastern Australia which burnt an area of 450,000 km2, with up to 400 individual fires being identified on February 7th 2009 alone. Driven by weeks of little or no rainfall and record-breaking temperatures, we show that the plumes from this event, contained enhanced VOC amounts and mixed within the lower stratosphere, reaching altitudes up to 18 km. Enhancement ratios, using CO as a reference, show potential secondary formation of HCOOH within the plume. We are able to track the evolution of the plume with IASI data for up to 20 days after the initial event. The second case study is comparison to results from a recent aircraft campaign over North America in July/August 2011 (BORTAS). The NERC-funded campaign was dedicated to studying the impact of local pollution events over North America and aged plumes originated from Asia and Siberia. In the context of the campaign aims, we investigated CO, VOC chemistry and aerosol signatures in boreal biomass plumes. The most significant event was a series of fires over North-west Ontario which we show released a significant quantity of CO and formic acid. The validation of IASI formic acid from this event with in-situ data is particularly good. We also derive the time-evolution of a variety of VOCs (including PAN) within aged plumes, using comparisons of MIPAS and ACE data. These plumes originate from both the boreal forests of North America and Siberia, and show excellent agreement between these independent datasets. Particularly large enhancements of PAN were discovered from Siberian forest fires in late July 2011.

Moore, David; Sembhi, Harjinder; Remedios, John; Tereszchuk, Keith

2013-04-01

229

Experimental investigation on regulated and unregulated emissions of a diesel/methanol compound combustion engine with and without diesel oxidation catalyst.  

PubMed

The use of methanol in combination with diesel fuel is an effective measure to reduce particulate matter (PM) and nitrogen oxides (NOx) emissions from in-use diesel vehicles. In this study, a diesel/methanol compound combustion (DMCC) scheme was proposed and a 4-cylinder naturally-aspirated direct-injection diesel engine modified to operate on the proposed combustion scheme. The effect of DMCC and diesel oxidation catalyst (DOC) on the regulated emissions of total hydrocarbons (THC), carbon monoxide (CO), NOx and PM was investigated based on the Japanese 13 Mode test cycle. Certain unregulated emissions, including methane, ethyne, ethene, 1,3-butadiene, BTX (benzene, toluene, xylene), unburned methanol and formaldehyde were also evaluated based on the same test cycle. In addition, the soluble organic fraction (SOF) in the particulate and the particulate number concentration and size distribution were investigated at certain selected modes of operation. The results show that the DMCC scheme can effectively reduce NOx, particulate mass and number concentrations, ethyne, ethene and 1,3-butadiene emissions but significantly increase the emissions of THC, CO, NO(2), BTX, unburned methanol, formaldehyde, and the proportion of SOF in the particles. After the DOC, the emission of THC, CO, NO(2), as well as the unregulated gaseous emissions, can be significantly reduced when the exhaust gas temperature is sufficiently high while the particulate mass concentration is further reduced due to oxidation of the SOF. PMID:19919875

Zhang, Z H; Cheung, C S; Chan, T L; Yao, C D

2010-01-15

230

Observations and models of emissions of volatile terpenoid compounds from needles of ponderosa pine trees growing in situ: control by light, temperature and stomatal conductance.  

PubMed

Terpenoid emissions from ponderosa pine (Pinus ponderosa subsp. scopulorum) were measured in Colorado, USA over two growing seasons to evaluate the role of incident light, needle temperature, and stomatal conductance in controlling emissions of 2-methyl-3-buten-2-ol (MBO) and several monoterpenes. MBO was the dominant daylight terpenoid emission, comprising on average 87% of the total flux, and diurnal variations were largely determined by light and temperature. During daytime, oxygenated monoterpenes (especially linalool) comprised up to 75% of the total monoterpenoid flux from needles. A significant fraction of monoterpenoid emissions was dependent on light and 13CO2 labeling studies confirmed de novo production. Thus, modeling of monoterpenoid emissions required a hybrid model in which a significant fraction of emissions was dependent on both light and temperature, while the remainder was dependent on temperature alone. Experiments in which stomata were forced to close using abscisic acid demonstrated that MBO and a large fraction of the monoterpene flux, presumably linalool, could be limited at the scale of seconds to minutes by stomatal conductance. Using a previously published model of terpenoid emissions, which explicitly accounts for the physicochemical properties of emitted compounds, we were able to simulate these observed stomatal effects, whether induced experimentally or arising under naturally fluctuation conditions of temperature and light. This study shows unequivocally that, under naturally occurring field conditions, de novo light-dependent monoterpenes comprise a significant fraction of emissions in ponderosa pine. Differences between the monoterpene composition of ambient air and needle emissions imply a significant non-needle emission source enriched in ?-3-carene. PMID:25015120

Harley, Peter; Eller, Allyson; Guenther, Alex; Monson, Russell K

2014-09-01

231

Influence of topography and biogenic volatile organic compounds emission in the state of Baden-Württemberg on ozone concentrations during episodes of high air temperatures  

NASA Astrophysics Data System (ADS)

A nonhydrostatic mesoscale model which is coupled with a transport and diffusion model and the gas phase mechanism RADM2 is used to study the influence of biogenic volatile organic compounds (VOC) emission on the ozone concentration during episodes of high air temperatures in the state of Baden-Württemberg, Germany. All model parts, including the determination of the biogenic VOC emissions, are run in a coupled mode. The results of the model simulations are compared with observations for a summer smog episode which occurred in August 1990. Simulations which are carried out without biogenic VOC emissions show a maximum difference in the ozone concentration of 18 ppb, while the maximum ozone values are of the order of 100 ppb. This shows that the biogenic VOC emissions play an important role when high temperatures are present in Baden-Württemberg. Simulations which are carried out with homogeneous terrain height show differences in the biogenic emissions caused by changes in the temperature distribution. Large differences are also found for the concentration distributions. The differences in the results which are obtained with and without biogenic VOC emissions are decreasing; the maximum difference is about 10 ppb. This demonstrates the necessity of a sufficient treatment of topographic effects in the regional scale.

Vogel, B.; Fiedler, F.; Vogel, H.

1995-11-01

232

Trends in multi-pollutant emissions from a technology-linked inventory for India: I. Industry and transport sectors  

NASA Astrophysics Data System (ADS)

Emissions estimation, for research and regulatory applications including reporting to international conventions, needs treatment of detailed technology divisions and high-emitting technologies. Here we estimate Indian emissions, for 1996-2015, of aerosol constituents (PM2.5, BC and OC) and precursor gas SO2, ozone precursors (CO, NOx, NMVOC and CH4) and greenhouse gases (CO2 and N2O), using a common fuel consumption database and consistent assumptions. Six source categories and 45 technologies/activities in the industry and transport sectors were used for estimating emissions for 2010. Mean emission factors, developed at the source-category level, were used with corresponding fuel consumption data, available for 1996-2011, projected to 2015. New activities were included to account for fugitive emissions of NMVOC from chemical and petrochemical industries. Dynamic emission factors, reflecting changes in technology-mix and emission regulations, were developed for thermal power plants and on-road transport vehicles. Modeled emission factors were used for gaseous pollutants for on-road vehicles. Emissions of 2.4 (0.6-7.5) Tg y-1 PM2.5, 0.23 (0.1-0.7) Tg y-1 BC, 0.15 (0.04-0.5) Tg y-1 OC, 7.3 (6-10) Tg y-1 SO2, 19 (7.5-33) Tg y-1 CO, 1.5 (0.1-9) Tg y-1 CH4, 4.3 (2-9) Tg y-1 NMVOC, 5.6 (1.7-15.9) Tg y-1 NOx, 1750 (1397-2231) Tg y-1 CO2 and 0.13 (0.05-0.3) Tg y-1 N2O were estimated for 2015. Significant emissions of aerosols and their precursors were from coal use in thermal power and industry (PM2.5 and SO2), and on-road diesel vehicles (BC), especially superemitters. Emissions of ozone precursors were largely from thermal power plants (NOx), on-road gasoline vehicles (CO and NMVOC) and fugitive emissions from mining (CH4). Highly uncertain default emission factors were the principal contributors to uncertainties in emission estimates, indicating the need for region specific measurements.

Sadavarte, Pankaj; Venkataraman, Chandra

2014-12-01

233

Assessment of China's virtual air pollution transport embodied in trade by a consumption-based emission inventory  

NASA Astrophysics Data System (ADS)

High anthropogenic emissions from China have resulted in serious air pollution, and it has attracted considerable academic and public concern. The physical transport of air pollutants in the atmosphere has been extensively investigated, however, understanding the mechanisms how the pollutants were transferred through economic and trade activities remains challenge. In this work, we assessed China's virtual air pollutant transport embodied in trade, by using consumption-based accounting approach. We first constructed a consumption-based emission inventory for China's four key air pollutants (primary PM2.5, sulfur dioxide (SO2), nitrogen oxides (NOx) and non-methane volatile organic compounds (NMVOC)) in 2007, based on the bottom-up sectoral emission inventory concerning their production activities - a production-based inventory. We used a multiregional input-output (MRIO) model to integrate the sectoral production-based emissions and the associated economic and trade activities, and finally obtained consumption-based inventory. Unlike the production-based inventory, the consumption-based inventory tracked emissions throughout the supply chain related to the consumption of goods and services and hereby identified the emission flows followed the supply chains. From consumption-based perspective, emissions were significantly redistributed among provinces due to interprovincial trade. Large amount of emissions were embodied in the net imports of east regions from northern and central regions; these were determined by differences in the regional economic status and environmental policies. We also calculated the emissions embodied in exported and imported goods and services. It is found that 15-23% of China's pollutant emissions were related to exports for foreign consumption; that proportion was much higher for central and export-oriented coastal regions. It is suggested that measures should be introduced to reduce air pollution by integrating cross-regional consumers and producers in national agreements to encourage efficiency improvement in the supply chain and optimizing consumption structure internationally. The consumption-based air pollutants emission inventory developed in this work can be further used to attribute pollution to different economic activities and final demand types with the aid of air quality models.

Zhao, H. Y.; Zhang, Q.; Davis, S. J.; Guan, D.; Liu, Z.; Huo, H.; Lin, J. T.; Liu, W. D.; He, K. B.

2014-10-01

234

Estimation of biogenic volatile organic compound (BVOC) emissions from the terrestrial ecosystem in China using real-time remote sensing data  

NASA Astrophysics Data System (ADS)

Because of the high emission rate and reactivity, biogenic volatile organic compounds (BVOCs) play a significant role in the terrestrial ecosystems, human health, secondary pollution, global climate change and the global carbon cycle. Past estimations of BVOC emissions in China were based on outdated algorithms and coarsely resolved meteorological data, and there have been significant inconsistences between the land surface parameters of dynamic models and those of BVOC estimation models, leading to large inaccuracies in the estimated results. To refine BVOC emission estimations for China and to further explore the role of BVOCs in the atmosphere, we used the latest algorithms of MEGAN (Model of Emissions of Gases and Aerosols from Nature), with MM5 (the Fifth-Generation Mesoscale Model) providing highly resolved meteorological data, to estimate the biogenic emissions of isoprene (C5H8) and seven monoterpene species (C10H16) in 2006. Real-time MODIS (Moderate Resolution Imaging Spectroradiometer) data were introduced to update the land surface parameters and to improve the simulation performance of MM5, and to determine the influence of leaf area index (LAI) and leaf age deviation from standard conditions. In this study, the annual BVOC emissions for the whole country totaled 12.97 Tg C, a relevant value compared with past studies. Therein, the most important individual contributor was isoprene (9.36 Tg C yr-1), followed by ?-pinene (1.24 Tg C yr-1) and ?-pinene (0.84 Tg C yr-1). Due to the considerable regional disparity in plant distributions and meteorological conditions across China, BVOC emissions presented significant spatial and temporal variations. Spatially, isoprene emission was concentrated in South China, which is covered by large areas of broadleaf forests and shrubs. While Southeast China was the top-ranking contributor of monoterpenes, in which the dominant vegetation genera consist of evergreen coniferous forests. Temporally, BVOC emissions primarily occurred in July and August, with daily emissions peaking at about 13:00∼14:00 h (Beijing Time, BJT). In this study, we present an improved estimation of BVOC emissions, which provides important information for further exploration of the role of BVOCs in atmospheric processes.

Li, M.; Huang, X.; Li, J.; Song, Y.

2012-03-01

235

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

236

The impact of China's vehicle emissions on regional air quality in 2000 and 2020: a scenario analysis  

NASA Astrophysics Data System (ADS)

The number of vehicles in China has been increasing rapidly. We evaluate the impact of current and possible future vehicle emissions from China on Asian air quality. We modify the Regional Emission Inventory in Asia (REAS) for China's road transport sector in 2000 using updated Chinese data for vehicle numbers, annual mileage and emission factors. We develop two scenarios for 2020: a scenario where emission factors remain the same as they were before any regulation was implemented (business-as-usual, BAU), and a scenario where Euro 3 vehicle emission standards are applied to all vehicles (except motorcycles and rural vehicles). The Euro 3 scenario is an approximation of what may be the case in 2020 as, starting in 2008, all new gasoline and diesel vehicles in China (except motorcycles) were required to meet the Euro 3 emission standards. Using the Weather Research and Forecasting model coupled with Chemistry (WRF/Chem), we examine the regional air quality response to China's vehicle emissions in 2000 and in 2020 for the BAU and Euro 3 scenarios. We evaluate the 2000 model results with observations in Japan, China, Korea, and Russia. Under BAU in 2020, emissions of carbon monoxide (CO), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), black carbon (BC) and organic carbon (OC) from China's vehicles more than double compared to the 2000 baseline. If all vehicles meet the Euro 3 regulations in 2020, however, these emissions are reduced by more than 50% relative to BAU. The implementation of stringent vehicle emission standards leads to a large, simultaneous reduction of the surface ozone (O3) mixing ratios and particulate matter (PM2.5) concentrations. In the Euro 3 scenario, surface O3 is reduced by more than 10 ppbv and surface PM2.5 is reduced by more than 10 ?g m-3 relative to BAU in Northeast China in all seasons. In spring, surface O3 mixing ratios and PM2.5 concentrations in neighboring countries are also reduced by more than 3 ppbv and 1 ?g m-3, respectively. We find that effective regulation of China's road transport sector will be of significant benefit for air quality both within China and across East Asia as well.

Saikawa, E.; Kurokawa, J.; Takigawa, M.; Mauzerall, D. L.; Horowitz, L. W.; Ohara, T.

2011-04-01

237

Multivariate analysis of effects of diurnal temperature and seasonal humidity variations by tropical savanna climate on the emissions of anthropogenic volatile organic compounds.  

PubMed

Volatile organic compounds (VOCs), particularly those from anthropogenic sources, have been of substantial concern. In this study, the influences of diurnal temperature and seasonal humidity variations by tropical savanna climate on the distributions of VOCs from stationary industrial sources were investigated by analyzing the concentrations during the daytime and nighttime in the dry and wet seasons and assessing the results by principal component analysis (PCA) and cluster analysis. Kaohsiung City in Southern Taiwan, known for its severe VOC pollution, was chosen as the location to be examined. In the results, the VOC concentrations were lower during the daytime and in the wet season, possibly attributed to the stronger photochemical reactions and increasing inhibition of VOC emissions and transports by elevating humidity levels. Certain compounds became appreciably more important at higher humidity, as these compounds were saturated hydrocarbons with relatively low molecular weights. The influence of diurnal temperature variation on VOC distribution behaviors seemed to be less important than and interacted with that of seasonal humidity variation. Heavier aromatic hydrocarbons with more complex structures and some aliphatic compounds were found to be the main species accounting for the maximum variances of the data observed at high humidity, and the distinct grouping of compounds implied a pronounced inherent characteristic of each cluster in the observed VOC distributions. Under the influence of diurnal temperature variation, selected VOCs that may have stronger photochemical resistances and/or longer lifetimes in the atmosphere were clustered with each other in the cluster analysis, whereas the other groups might consist of compounds with different levels of vulnerability to sunlight or high temperatures. These findings prove the complications in the current knowledge regarding the VOC contaminations and providing insight for managing the adverse impacts of the anthropogenic VOCs on the environment and public health. PMID:24144936

Liu, Chih-Chung; Chen, Wei-Hsiang; Yuan, Chung-Shin; Lin, Chitsan

2014-02-01

238

Bioassay-directed chemical analysis of organic extracts of emissions from a laboratory-scale incinerator: Combustion of surrogate compounds  

SciTech Connect

A prototype/laboratory-scale rotary kiln (73 kW, 250,000 Btu/h) was used to examine the chemical composition and biological effects of the emissions produced when the kiln was operated under suboptimal conditions resulting from batch charging. The surrogate wastes evaluated were polyethylene (PE), polyvinylchloride (PVC), toluene (TOL), carbon tetrachloride (CC14), PE + PVC and TOL + CC14. The dichloromethane-extractable organics from particles (collected on filters) and semivolatiles (collected on XAD-2 resin) were evaluated for mutagenic activity using the Salmonella (Ames) mutagenicity assay in strain TA98 (+S9). The mutagenic potencies (revertants/microgram of extractable organics) of the emissions ranked as follows: PE > TOL > PE + PVC > TOL + CC14. The organic extracts from the PVC and CC14 emissions were not mutagenic.

DeMarini, D.M.; Williams, R.W.; Perry, E.; Lemieux, P.M.; Linak, W.P.

1992-01-01

239

Opportunity Analysis for Recovering Energy from Industrial Waste Heat and Emissions  

SciTech Connect

United States industry consumed 32.5 Quads (34,300 PJ) of energy during 2003, which was 33.1% of total U.S. energy consumption (EIA 2003 Annual Energy Review). The U.S. industrial complex yields valuable goods and products. Through its manufacturing processes as well as its abundant energy consumption, it supports a multi-trillion dollar contribution to the gross domestic product and provides millions of jobs in the U.S. each year. Industry also yields waste products directly through its manufacturing processes and indirectly through its energy consumption. These waste products come in two forms, chemical and thermal. Both forms of waste have residual energy values that are not routinely recovered. Recovering and reusing these waste products may represent a significant opportunity to improve the energy efficiency of the U.S. industrial complex. This report was prepared for the U.S. Department of Energy Industrial Technologies Program (DOE-ITP). It analyzes the opportunity to recover chemical emissions and thermal emissions from U.S. industry. It also analyzes the barriers and pathways to more effectively capitalize on these opportunities. A primary part of this analysis was to characterize the quantity and energy value of the emissions. For example, in 2001, the industrial sector emitted 19% of the U.S. greenhouse gases (GHG) through its industrial processes and emitted 11% of GHG through electricity purchased from off-site utilities. Therefore, industry (not including agriculture) was directly and indirectly responsible for emitting 30% of the U.S. GHG. These emissions were mainly comprised of carbon dioxide (CO2), but also contained a wide-variety of CH4 (methane), CO (carbon monoxide), H2 (hydrogen), NMVOC (non-methane volatile organic compound), and other chemicals. As part of this study, we conducted a survey of publicly available literature to determine the amount of energy embedded in the emissions and to identify technology opportunities to capture and reuse this energy. As shown in Table E-1, non-CO2 GHG emissions from U.S. industry were identified as having 2180 peta joules (PJ) or 2 Quads (quadrillion Btu) of residual chemical fuel value. Since landfills are not traditionally considered industrial organizations, the industry component of these emissions had a value of 1480 PJ or 1.4 Quads. This represents approximately 4.3% of the total energy used in the United States Industry.

Viswanathan, Vish V.; Davies, Richard W.; Holbery, Jim D.

2006-04-01

240

Laboratory scale evaluation of volatile organic compound emissions as indication of swine carcass degradation inside biosecure composting units  

Microsoft Academic Search

Biosecure livestock mortality composting systems have been used to dispose of diseased livestock mortalities. In those types of system, visual inspection of carcass degradation is not possible and monitoring VOCs (volatile organic compounds) released by carcasses is a new approach to assess progress of the composting process. In this study, field-scale livestock mortality composting systems were simulated and a laboratory

Neslihan Akdeniz; Jacek A. Koziel; Hee-Kwon Ahn; Thomas D. Glanville; Benjamin P. Crawford; D. Raj Raman

2010-01-01

241

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...

242

USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS  

EPA Science Inventory

Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference sa...

243

SEMI-VOLATILE ORGANIC COMPOUNDS FROM VEHICLES POWERED BY GASOLINE, DIESEL AND ALTERNATIVE FUELS: EMISSIONS AND FIELD MEASUREMENTS  

EPA Science Inventory

This study will result in the development of a new method for the rapid measurement of SVOCs. The characterization of VOC and SVOC emissions of vehicles with different fuel types will improve our understanding of the processes leading to secondary organic aerosol pollution and...

244

BIOASSAY-DIRECTED CHEMICAL ANALYSIS OF ORGANIC EXTRACTS OF EMISSIONS FROM A LABORATORY-SCALE INCINERATOR: COMBUSTION OF SURROGATE COMPOUNDS  

EPA Science Inventory

The paper describes using a prototype/pilot-scale rotary kiln (73 kill) to examine the chemical composition and biological effect's of emissions produced when operating the kiln under suboptimal conditions resulting from batch charging. he surrogate wastes evaluated included comb...

245

SIMULTANEOUS DETERMINATION OF ORGANOTIN, ORGANOLEAD, AND ORGANOMERCURY COMPOUNDS IN ENVIRONMENTAL SAMPLES USING CAPILLARY GAS CHROMATOGRAPHY WITH ATOMIC EMISSION DETECTION  

EPA Science Inventory

As part of a continuing evaluation of new analytical and sample preparation techniques conducted by the US Environmental Protection Agency (EPA), the use of capillary gas chromatography with atomic emission detection (GC-AED) for the simultaneous determination of organotin, organ...

246

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

247

Signal enhancement in solution-cathode glow discharge — optical emission spectrometry via low molecular weight organic compounds  

NASA Astrophysics Data System (ADS)

HCOOH, CH3COOH, and CH3CH2OH were used as chemical modifiers in a solution-cathode glow discharge. Emission was measured directly from the discharge, without a gas-liquid separator or a secondary excitation source. Emission from Ag, Se, Pb, and Hg was strongly enhanced, and the detection limits (DL) for these elements were improved by up to an order of magnitude using a combination of HCOOH and HNO3 compared to using HNO3 alone. The DL was measured for Mg (1 ?g/L), Fe (10 ?g/L), Ni (6 ?g/L), Cu (6 ?g/L), Pb (1 ?g/L), Ag (0.1 ?g/L), Se (300 ?g/L), and Hg (2 ?g/L). Coefficients of determination (R2) were between 0.9986 and 0.9999. A voltage of 1 kV was used, which produced a current of approximately 70 mA.

Doroski, Todd A.; Webb, Michael R.

2013-10-01

248

Atmospheric emissions and attenuation of non-methane organic compounds in cover soils at a French landfill.  

PubMed

In addition to methane (CH(4)) and carbon dioxide (CO(2)), landfill gas may contain more than 200 non-methane organic compounds (NMOCs) including C(2+)-alkanes, aromatics, and halogenated hydrocarbons. Although the trace components make up less than 1% v/v of typical landfill gas, they may exert a disproportionate environmental burden. The objective of this work was to study the dynamics of CH(4) and NMOCs in the landfill cover soils overlying two types of gas collection systems: a conventional gas collection system with vertical wells and an innovative horizontal gas collection layer consisting of permeable gravel with a geomembrane above it. The 47 NMOCs quantified in the landfill gas samples included primarily alkanes (C(2)-C(10)), alkenes (C(2)-C(4)), halogenated hydrocarbons (including (hydro)chlorofluorocarbons ((H)CFCs)), and aromatic hydrocarbons (BTEXs). In general, both CH(4) and NMOC fluxes were all very small with positive and negative fluxes. The highest percentages of positive fluxes in this study (considering all quantified species) were observed at the hotspots, located mainly along cell perimeters of the conventional cell. The capacity of the cover soil for NMOC oxidation was investigated in microcosms incubated with CH(4) and oxygen (O(2)). The cover soil showed a relatively high capacity for CH(4) oxidation and simultaneous co-oxidation of the halogenated aliphatic compounds, especially at the conventional cell. Fully substituted carbons (TeCM, PCE, CFC-11, CFC-12, CFC-113, HFC-134a, and HCFC-141b) were not degraded in the presence of CH(4) and O(2). Benzene and toluene were also degraded with relative high rates. This study demonstrates that landfill soil covers show a significant potential for CH(4) oxidation and co-oxidation of NMOCs. PMID:18032020

Scheutz, C; Bogner, J; Chanton, J P; Blake, D; Morcet, M; Aran, C; Kjeldsen, P

2008-01-01

249

Determination of white phosphorus residues in ducks: An atomic emission detection/compound-independent calibration-based method of generating residue data for risk assessment and environmental monitoring  

SciTech Connect

Analysis of phosphorus concentrations in the gizzards of ducks harvested from munitions sites is necessary to ascertain if acute phosphorus toxicity was the cause of death and to estimate potential secondary hazards to predators and scavengers, such as eagles that readily consume the dead ducks. Gas chromatography-atomic emission detection analysis permitted compound-independent quantification of white phosphorus standards following analysis of the stable phosphorus-containing compound triethyl phosphate. The white phosphorus standards were then used to quantify white phosphorus residues in duck gizzard extracts by gas chromatography-flame photometric detection analysis. For gizzards containing less than 0.01 {micro}g of phosphorus, quantification was based on a three-point calibration curve. For gizzards containing 0.01 {micro}g or more of white phosphorus, single-point calibration was used. Mean recoveries for phosphorus-fortified gizzards ranged from 73 to 91%. The method limit of detection was 0.013 {micro}g of phosphorus. This method was successfully applied to the quantification of white phosphorus in ducks collected from Eagle River Flats, AK. Potential applications to risk assessment and environmental monitoring are also discussed.

Johnston, J.J.; Goldade, D.A.; Kohler, D.J.; Cummings, J.L.

2000-05-01

250

Regional biogenic emissions of reactive volatile organic compounds (BVOC) from forests: First results on process studies, modelling and validation experiments (BEWA2000)  

NASA Astrophysics Data System (ADS)

The overall objective of the research consortia is to develop for a forest canopy a prognostic, validated emission model for primary and secondary volatile organic compounds (VOC) to be used for estimating regional biogenic emissions with a higher spatial and temporal resolution than present. To achieve this objective requires a better description of biosynthetic processes as well as chemical degradation mechanisms for reactive biogenic VOC in combination with a process-based model and latest vegetation specific land use information. Up to now several highlights were achieved within the different key activities. In the section model development a process-based isoprenoid emission model was supplemented with new differential equations especially taking into account the influence of transport-resistances for leaf gas-exchange. In biochemical process-studies related to the formation of isoprene in leaves it turned out that during daytime about 20-70% of the total carbon delivered to poplar leaves (photosynthesis + other sources) was derived from xylem-transported sugars. This finding indicates that xylem-delivered carbon may indeed act as a significant alternative carbon source for isoprenoid biosynthesis. First chemical process studies on the reaction of limonene with NO3 radicals (observed in the night and under low light conditions) in the EUPHORE (European Photoreactor) demonstrated a secondary particle formation. At the field site Waldstein (Fichtelgebirge) this reaction may result in maximum pinonealdhyde concentrations in the air and on particles observed in night periods. A first analysis of particle size distributions over the Norway spruce canopy showed the appearance of small particles (< 10nm) during early daytime. The first results demonstrate that the proposed approach of combining interdisciplinary field, laboratory and modelling exercises to address the complexity of the biosphere/atmosphere exchange of reactive trace gases will contribute significantly to enhance our knowledge in this field needed for improving process based models. However, still poorly understood processes (e.g air chemistry under low light conditions, biochemical control of VOC emission) require further studies. It will be a challenging task in the future to close the reactive carbon mass-balance and to see how the new models are able to simulate more complex situations, e.g. the results from the ECHO project.

Rappenglück, B.; Bewa2000 Team

2003-04-01

251

Spatial surrogates for the disaggregation of CORINAIR emission inventories  

NASA Astrophysics Data System (ADS)

CORINAIR atmospheric emission inventories are frequently used input data for air quality models with a domain situated in Europe. In CORINAIR emission inventories, sources are broken down over 11 major source categories. This paper presents spatial surrogates for the disaggregation of CORINAIR atmospheric emission inventories for input of air pollutants and particulate matter to grid or polygon based air quality model domains inside Europe. The basis for the disaggregation model was the CLC2000 land cover data to which statistical weights were added. Weights were population census data for residential emissions, employment statistics for agricultural and industrial area emissions, livestock statistics for ammonia emissions and annual aircraft movements for emissions realized by air transport. Additional road and off-road network information was used to disaggregate emissions realized by traffic. A comparison of top down produced emission estimates with spatially resolved national emission data for The Netherlands and the United Kingdom gave confidence in the present spatial surrogates as a tool for the top down production of atmospheric emission maps. Explained variance at a spatial resolution of 5 km was >70% for CO, NMVOC and NO x, >60% for PM10 and almost 50% for SO 2.

Maes, Joachim; Vliegen, Jo; Van de Vel, Karen; Janssen, Stijn; Deutsch, Felix; De Ridder, Koen; Mensink, Clemens

252

Emissions from India's transport sector: Statewise synthesis  

NASA Astrophysics Data System (ADS)

A decentralized emission inventories are prepared for road transport sector of India in order to design and implement suitable technologies and policies for appropriate mitigation measures. Globalization and liberalization policies of the government in 90's have increased the number of road vehicles nearly 92.6% from 1980-1981 to 2003-2004. These vehicles mainly consume non-renewable fossil fuels, and are a major contributor of green house gases, particularly CO 2 emission. This paper focuses on the statewise road transport emissions (CO 2, CH 4, CO, NO x, N 2O, SO 2, PM and HC), using region specific mass emission factors for each type of vehicles. The country level emissions (CO 2, CH 4, CO, NO x, N 2O, SO 2 and NMVOC) are calculated for railways, shipping and airway, based on fuel types. In India, transport sector emits an estimated 258.10 Tg of CO 2, of which 94.5% was contributed by road transport (2003-2004). Among all the states and Union Territories, Maharashtra's contribution is the largest, 28.85 Tg (11.8%) of CO 2, followed by Tamil Nadu 26.41 Tg (10.8%), Gujarat 23.31 Tg (9.6%), Uttar Pradesh 17.42 Tg (7.1%), Rajasthan 15.17 Tg (6.22%) and, Karnataka 15.09 Tg (6.19%). These six states account for 51.8% of the CO 2 emissions from road transport.

Ramachandra, T. V.; Shwetmala

253

Global chemical transport model study of ozone response to changes in chemical kinetics and biogenic volatile organic compounds emissions due to increasing temperatures: Sensitivities to isoprene nitrate chemistry and grid resolution  

Microsoft Academic Search

Global modeling studies show a wide variability in the response of the O3 budget to climate change as projected by applying Intergovernmental Panel on Climate Change scenarios in climate models. We employ sensitivity studies to elucidate the major uncertainties in the response of tropospheric O3 to perturbations in biogenic volatile organic compounds (BVOC) emissions and reaction rate coefficients due to

Akinori Ito; Sanford Sillman; Joyce E. Penner

2009-01-01

254

Potential odorous volatile organic compound emissions from feces and urine from cattle fed corn-based diets with wet distillers grains and solubles  

NASA Astrophysics Data System (ADS)

Odor and volatile organic compound (VOC) emissions are a concern at animal feeding operations (AFOs). The issue has become more prevalent as human residences move into areas once occupied only by agriculture. Odors near AFOs are generally caused by odorous VOCs emitted from manure, the mixture of feces and urine. Wet distillers grains with solubles (WDGS) are a by-product of the ethanol industry, and WDGS have become a staple in many beef cattle finishing diets. The objective of this research was to determine specific VOC emissions from frozen feces and urine of cattle fed steam-flaked corn (SFC)-based diets containing 0, 15, 30, or 45% WDGS. No differences in flux were detected across dietary treatments for phenol, indole, skatole, or 4-methylphenol (P > 0.23). Dimethyl disulfide and dimethyl trisulfide flux in feces were not different across treatments (P > 0.35) and the flux of volatile fatty acids (VFA) such as acetic, propionic, isobutyric, butyric, isovaleric, and valeric were not different across treatments (P > 0.25). There was a tendency for dimethyl disulfide flux from urine to be greater for cattle consuming an SFC-based diet with 15% WDGS than the other diets (P = 0.10). Furthermore, flux of acetic, propionic, isobutyric, butyric, and isovaleric acid from the urine were not different (P > 0.61) across dietary treatment. There were no significant differences in odor activity value (OAV) across treatments for feces, and only a tendency for dimethyl disulfide in the feces (P = 0.09). Thus, there was no obvious indication that feeding WDGS in conjunction with SFC affects flux of odor or odorous VOC from beef manure. The summed OAV was three times higher in the urine than feces, and a single odorous compound (4-methylphenol) accounted for 97.6%and 67.3% of the OAV in urine and feces, respectively. Therefore, engineering or dietary strategies to reduce odor from beef cattle manure should focus on controlling or reducing 4-methylphenol concentrations in the urine and feces.

Hales, Kristin E.; Parker, David B.; Cole, N. Andy

2012-12-01

255

Monitoring the emission of volatile organic compounds from flowers of Jasminum sambac using solid-phase micro-extraction fibers and gas chromatography with mass spectrometry detection.  

PubMed

Solid-phase micro-extraction (SPME) was studied as a solvent free alternative method for the extraction and characterization of volatile compounds in intact and plucked flowers of Jasminum sambac at different day time intervals using gas chromatography (GC-FID) and gas chromatography-quadrupole mass spectrometry. The analytes identified included alcohols, esters, phenolic compounds, and terpenoids. The main constituents identified in the flower aroma using different fibers were cis-3-hexenyl acetate, (E)-beta-ocimene, linalool, benzyl acetate, and (E,E)-alpha-farnesene. The benzyl acetate proportion decreased from morning to afternoon and then increased in evening collections. PDMS fiber showed a high proportion of (E,E)-alpha-farnesene in jasmine floral aroma. Among other constituents identified, cis-3-hexenyl acetate, linalool, and benzyl acetate were major aroma contributors in plucked and living flowers extracts using PDMS/DVB, Carboxen/PDMS, and DVB/Carboxen/PDMS fibers. PDMS/DVB recorded the highest emission for benzyl acetate while the (E)-beta-ocimene proportion was highest in DVB/Carboxen/PDMS when compared with the rest. The highest linalool content, with increasing proportion from morning to noon, was found using mixed coating fibers. Almost negligible volatile adsorption was recorded for the polyacrylate fiber for intact flower aroma, whereas it was most effective for benzyl acetate, followed by indole under plucked conditions. Moreover, the highest amounts extracted, evaluated from the sum of peak areas, were achieved using Carboxen/PDMS, and DVB/Carboxen/PDMS. Introduction of a rapid, and solvent free SPME method for the analysis of multicomponent volatiles can be successfully employed to monitor the extraction and characterization of flower aroma constituents. PMID:21941909

Pragadheesh, Vppalayam Shanmugam; Yadav, Anju; Chanotiya, Chandan Singh; Rout, Prasanta Kumar; Uniyal, Girish Chandra

2011-09-01

256

Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species  

NASA Astrophysics Data System (ADS)

Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photooxidation under a range of controlled conditions (RH ∼65-89%, VOC/NOx ∼3-9 and NOx ∼2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line, chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene, but low isoprene emitter, and its emissions were observed to produce measureable amounts of SOA via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e., in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photooxidation products of the minor VOCs co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally-isoprene emitting landscapes in Southeast Asia. Moreover, in general the amount of aerosol mass produced from the emissions of the principally-isoprene-emitting plants, was less than would be expected from published single-VOC experiments, if co-emitted species were solely responsible for the final SOA mass. Interpretation of the results obtained from the fig data sets, leaves room for a potential role for isoprene in inhibiting SOA formation under certain ambient atmospheric conditions, although instrumental and experimental constraints impose a level of caution in the interpretation of the results. Concomitant gas and aerosol phase composition measurements also provide a detailed overview of numerous key oxidation mechanisms at work within the systems studied and their combined analysis provides insight into the nature of the SOA formed.

Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

2014-06-01

257

Production of phenolics and the emission of volatile organic compounds by perennial ryegrass (Lolium perenne L.)/Neotyphodium lolii association as a response to infection by Fusarium poae.  

PubMed

Grasses very often form symbiotic associations with Neotyphodium/Epichloë endophytic fungi. These endophytes often allow the host grass to be protected from different pathogens. However, there is little known about the mechanisms of such endophyte influence on the host. Thus, the purpose of this research was to examine the effect of the N. lolii endophyte on the total production of phenolic compounds, VOCs emission and the resistance of three perennial ryegrass genotypes infected by pathogenic Fusarium poae. Analyses of total phenolics content were performed in control (not inoculated) and inoculated plants after 1, 2, 3, 4, 5, and 6 days (DAI) and for VOCs after 0, 3, 6 and 12 DAI. The presence of endophytes significantly reduced the disease index in two of the three genotypes relative to that in E-. Plants infected by N. lolii exhibited higher production of phenolics relative to the E- plants. The highest amounts of phenolics were observed on the second and sixth DAI. Genotype Nl22 showed the strongest effect of the endophyte on the production of phenolics, which increased by over 61%. Both the endophyte infected and non-infected plants emitted most abundantly two GLVs ((Z)-3-hexenal, (Z)-3-hexen-1-yl acetate), three terpenes (linalool, (Z)-ocimene, ?-caryophyllene) and three shikimic acid pathway derivatives (benzyl acetate, indole, and methyl salicylate). The endophyte presence and the intervals of VOCs detection were a highly significant source of variation for all emitted volatiles (P<0.001). The genotype of the perennial ryegrass significantly affected only the emission of methyl salicylate (P<0.05) and ?-caryophyllene (P<0.05). Most of the VOCs ((Z)-3-hexen-1-yl acetate, (Z)-3-hexenal, linalool and methyl salicylate) reached their highest levels of emission on the sixth DAI, when averaged over genotypes and endophyte status. The results highlight the role of Neotyphodium spp. in the mediation of quadro-trophic interactions among plants, symbiotic endophytes, invertebrate herbivores and plant pathogenic fungi. Our results also confirm the fact that symbiotic plants can activate a defense reaction faster than non-symbiotic plants after a pathogen attack. Thus, N. lolii can be involved in the defense of perennial ryegrass against pathogens and potentially could be central to the host plants' protection. PMID:23566872

Pa?ka, Dariusz; Piesik, Dariusz; Jeske, Ma?gorzata; Baturo-Cie?niewska, Anna

2013-07-15

258

Biogenic Volatile Organic Compound and Respiratory CO2 Emissions after 13C-Labeling: Online Tracing of C Translocation Dynamics in Poplar Plants  

PubMed Central

Background Globally plants are the primary sink of atmospheric CO2, but are also the major contributor of a large spectrum of atmospheric reactive hydrocarbons such as terpenes (e.g. isoprene) and other biogenic volatile organic compounds (BVOC). The prediction of plant carbon (C) uptake and atmospheric oxidation capacity are crucial to define the trajectory and consequences of global environmental changes. To achieve this, the biosynthesis of BVOC and the dynamics of C allocation and translocation in both plants and ecosystems are important. Methodology We combined tunable diode laser absorption spectrometry (TDLAS) and proton transfer reaction mass spectrometry (PTR-MS) for studying isoprene biosynthesis and following C fluxes within grey poplar (Populus x canescens) saplings. This was achieved by feeding either 13CO2 to leaves or 13C-glucose to shoots via xylem uptake. The translocation of 13CO2 from the source to other plant parts could be traced by 13C-labeled isoprene and respiratory 13CO2 emission. Principal Finding In intact plants, assimilated 13CO2 was rapidly translocated via the phloem to the roots within 1 hour, with an average phloem transport velocity of 20.3±2.5 cm h?1. 13C label was stored in the roots and partially reallocated to the plants' apical part one day after labeling, particularly in the absence of photosynthesis. The daily C loss as BVOC ranged between 1.6% in mature leaves and 7.0% in young leaves. Non-isoprene BVOC accounted under light conditions for half of the BVOC C loss in young leaves and one-third in mature leaves. The C loss as isoprene originated mainly (76–78%) from recently fixed CO2, to a minor extent from xylem-transported sugars (7–11%) and from photosynthetic intermediates with slower turnover rates (8–11%). Conclusion We quantified the plants' C loss as respiratory CO2 and BVOC emissions, allowing in tandem with metabolic analysis to deepen our understanding of ecosystem C flux. PMID:21387007

Ghirardo, Andrea; Gutknecht, Jessica; Zimmer, Ina; Bruggemann, Nicolas; Schnitzler, Jorg-Peter

2011-01-01

259

Weiterentwicklung und Erprobung von Immissionsmessverfahren fuer gesundheitsgefaehrdende organische Stoffe. (Further development and testing of emission measuring techniques for organic compounds with health risks).  

National Technical Information Service (NTIS)

Some devices are developed that may be combined to measurement systems for the selective determination of volatile organic compounds (VOC) with health risks in ambient air. The measurement methods will be used instead of the methods for the determination ...

H. Manns, G. Nitz, B. Striefler

1990-01-01

260

Role of Planar Defects in Compound Semiconductor Crystals: From Growth of Nanomasts & Nanosails to Processing Light Emission in DualBeam FIB/SEM.  

E-print Network

to Processing Light Emission in DualBeam FIB/SEM. W.MoberlyChan*, J. Tringe*, I.Shalish**, & V} facets. The DualBeam FIB/SEM (FEI-NOVA-600), with a Cathodoluminescence spectrometer, provides an in situ of nanowires [3, 4]. Figure 3 presents an SEM image and CL data [3] from GaN nanowires (growth orientation

Shalish, Ilan

261

A BIOGENIC ROLE IN EXPOSURE TO TWO TOXIC COMPOUNDS  

EPA Science Inventory

Biogenic sources play an important role in ozone and particulate concentrations through emissions of volatile organic compounds. The same emissions also contribute to chronic toxic exposures from formaldehyde and acetaldehyde because each compound arises through primary and se...

262

Estimation of the dioxin emission (PCDD\\/FI-TEQ) from the concentration of low chlorinated aromatic compounds in the flue and stack gas of a hazardous waste incinerator  

Microsoft Academic Search

The concentrations of hexa- and pentachlorobenzene in the flue gases of waste incinerators are known to be strongly correlated with the emission of polychlorinated dibenzo-p-dioxins\\/furans PCDD\\/F, measured in international toxicity equivalents, I-TEQ. In this work it was investigated whether polychlorinated benzenes (PCBz) with a lower degree of chlorination and mono- and dichlorinated dibenzo-p-dioxins\\/furans can be used for estimation of the

M. Blumenstock; R. Zimmermann; K.-W. Schramm; A. Kaune; U. Nikolai; D. Lenoir; A. Kettrup

1999-01-01

263

75 FR 64673 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Limiting Emissions of...  

Federal Register 2010, 2011, 2012, 2013

...Plans; Delaware; Limiting Emissions of Volatile Organic Compounds From Consumer Products...Regulation No. 41)--Limiting Emissions of Volatile Organic Compounds from [[Page 64674...Regulation No. 41-- Limiting Emissions of Volatile Organic Compounds from Consumer and...

2010-10-20

264

A high-resolution and multi-year emissions inventory for biomass burning in Southeast Asia during 2001-2010  

NASA Astrophysics Data System (ADS)

Biomass burning (BB) emissions from forest fires, agricultural waste burning, and peatland combustion contain large amounts of greenhouse gases (e.g., CO2, CH4, and N2O), which significantly impact ecosystem productivity, global atmospheric chemistry, and climate change. With the help of recently released satellite products, biomass density based on satellite and observation data, and spatiotemporal variable combustion factors, this study developed a new high-resolution and multi-year emissions inventory for BB in Southeast Asia (SEA) during 2001-2010. The 1-km grid was effective for quantifying emissions from small-sized fires that were frequently misinterpreted by coarse grid data due to their large smoothed pixels. The average annual BB emissions in SEA during 2001-2010 were 277 Gg SO2, 1125 Gg NOx, 55,388 Gg CO, 3831 Gg NMVOC, 553 Gg NH3, 324 Gg BC, 2406 Gg OC, 3832 Gg CH4, 817,809 Gg CO2, and 99 Gg N2O. Emissions were high in western Myanmar, Northern Thailand, eastern Cambodia, northern Laos, and South Sumatra and South Kalimantan of Indonesia. Emissions from forest burning were the dominant contributor to the total emissions among all land types. The spatial pattern of BB emissions was consistent with that of the burned areas. In addition, BB emissions exhibited similar temporal trends from 2001 to 2010, with strong interannual and intraannual variability. Interannual and intraannual emission peaks were seen during 2004, 2007, 2010, and January-March and August-October, respectively.

Shi, Yusheng; Yamaguchi, Yasushi

2014-12-01

265

Characterization of Halyomorpha halys (brown marmorated stink bug) biogenic volatile organic compound emissions and their role in secondary organic aerosol formation.  

PubMed

The formation of aerosols is a key component in understanding cloud formation in the context of radiative forcings and global climate modeling. Biogenic volatile organic compounds (BVOCs) are a significant source of aerosols, yet there is still much to be learned about their structures, sources, and interactions. The aims of this project were to identify the BVOCs found in the defense chemicals of the brown marmorated stink bug Halymorpha halys and quantify them using gas chromatography-mass spectrometry (GC/MS) and test whether oxidation of these compounds by ozone-promoted aerosol and cloud seed formation. The bugs were tested under two conditions: agitation by asphyxiation and direct glandular exposure. Tridecane, 2(5H)-furanone 5-ethyl, and (E)-2-decenal were identified as the three most abundant compounds. H. halys were also tested in the agitated condition in a smog chamber. It was found that in the presence of 100-180 ppm ozone, secondary aerosols do form. A scanning mobility particle sizer (SMPS) and a cloud condensation nuclei counter (CCNC) were used to characterize the secondary aerosols that formed. This reaction resulted in 0.23 microg/ bug of particulate mass. It was also found that these secondary organic aerosol particles could act as cloud condensation nuclei. At a supersaturation of 1%, we found a kappa value of 0.09. Once regional populations of these stink bugs stablilize and the populations estimates can be made, the additional impacts of their contribution to regional air quality can be calculated. PMID:24344570

Solomon, Danielle; Dutcher, Dabrina; Raymond, Timothy

2013-11-01

266

Transient response of blue organic electroluminescence devices with short fluorescence lifetime of substituted phenyl/vinyl compound as an emissive layer.  

PubMed

We have demonstrated a short fluorescence lifetime of the substituted phenyl/vinyl compound, 1,4-bis[2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene (DSB). The fluorescence lifetime of the 0.5 mol.% DSB-doped 4,4'-bis(9-carbazolyl)biphenyl film is 1.2 ns, which is desirable for organic light-emitting diode (OLED) light sources for optical interconnect applications. We have also examined frequency dependences on the electroluminescence (EL) intensity of the OLED and the photoluminescence (PL) intensity of the DSB film. The -3 dB cutoff frequency of the EL intensity is about 3 MHz for the optimized device, and the -3dB cutoff frequency of the PL intensity is about 160 MHz for the optically pumping DSB film. PMID:17410265

Fukuda, Takeshi; Ohashi, Masakazu; Wei, Bin; Okada, Tomoko; Ichikawa, Musubu; Taniguchi, Yoshio

2007-05-01

267

Compound Interest  

NSDL National Science Digital Library

Albert Einstein called compound interest the 8th wonder of the world. Find out why compound interest and the time value of money are so important. What is Interest Click on the following link to read about the different types of interest. Loans and Interest So why learn about compound interest? Using time and interest to your advantage, you can make more money than you have ever dreamed of. See how the time value of ...

Riches, Ms.

2007-10-16

268

Speciation analysis of triethyl-lead and tributyl-tin compounds in human urine by liquid-liquid extraction and gas chromatography microwave-induced plasma atomic emission detection.  

PubMed

This work describes the development of a fast method for speciation analysis of triethyl-lead and tributyl-tin species in urine samples after in situ derivatization by tetraethyl- or tetrapropyl-borate reagents. The alkylation reaction is done in the aqueous and urine medium and the less-polar derivatives are extracted in hexane by liquid-liquid extraction. The species were extracted and the extract was efficiently collected from the aqueous phase after centrifugation. Finally, the organometallic species are separated by gas chromatography and determined from the emission signals of elemental lead and tin. Atomic lead and tin are formed from the organolead and organotin compounds during atomization of the column eluate in a microwave-induced helium plasma source. The simultaneous measurement of lead (Pb) at 405.780 nm and tin (Sn) at 303.419 nm was achieved by an atomic emission detector. Finally, the analytes were determined with satisfactory precision (<5%) and detection limits of 0.05 ?g Pb/L and 0.48 ?g Sn/L, respectively, when 10 mL of urine is extracted with 1 mL of hexane and 1 ?L of extract is injected. PMID:22689489

Zachariadis, George A; Rosenberg, Erwin

2012-05-01

269

Role of fossil fuel and wood burning emissions on Volatile Organic Compounds, Carbon monoxide and Black Carbon level and variability as determined from one-year measurements in Paris.  

NASA Astrophysics Data System (ADS)

Within the French program PRIMEQUAL-FRANCIPOL 2010-2013, measurements of gaseous precursors of secondary organic aerosols have been performed at the LHVP (Laboratoire d'Hygiene de la Ville de Paris), an urban background site of Paris. A continuous real-time monitoring strategy using the high sensitivity PTR-MS (Proton Transfer Reaction- Mass Spectrometer) has been implemented for the measurements of Volatile Organic Compounds (VOCs) during a whole year (02/2010-03/2011). The data were acquired in mass-scan mode thus, allowing to follow a very wide range of analytes, namely between m/z 18 and 151. This broad range of compounds includes both well-known VOCs and less studied ones, providing a great exploration potential and the opportunity to establish novel valuable information. This unique dataset will enable to acquire a better understanding of the diurnal, weekday and seasonal trends and to determine the main sources that drive VOCs variability in Paris. The preliminary results herein aim to distinguish the biomass burning from the fuel fossil emissions and to evaluate their impact on the measured volatile organic compounds using tracers Black Carbon (BC) and carbon monoxide (CO). BC was measured and separated into fuel fossil (FF) and wood burning (WB) contributions which can both be used as tracers. The obtained FF contributions to BC are well correlated with measured concentrations of acetaldehyde (m/z 45), acetone (m/z 59), hexanal (m/z 83), probably chloroethane (m/z 85), dimethylbenzene (m/z 107) and trimethylbenzene (TMB) while WB contributions to BC correlate nicely with methanol and the mass 97, maybe related to furfural which has already been identified in smoke from woodburning.

Sarda Esteve, R.; Gros, V.; Kalogridis, A.-C.; Sciare, J.

2012-04-01

270

The Influence of Ozone Precursor Emissions from Four World Regions on Tropospheric Composition and Radiative Climate Forcing  

NASA Technical Reports Server (NTRS)

Ozone (O3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O3 and oxidants, which also influence methane (CH4) and sulfate aerosols (SO4 (sup 2-)). We examine changes in the tropospheric composition of O3, CH4, SO4 (sup 2-) and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O3 precursor emissions (NOx, NMVOC, and CO) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations, assessing uncertainty (mean plus or minus 1 standard deviation) across multiple CTMs. We evaluate steady state O3 responses, including long-term feedbacks via CH4. With a radiative transfer model that includes greenhouse gases and the aerosol direct effect, we find that regional NOx reductions produce global, annually averaged positive net RFs (0.2 plus or minus 0.6 to 1.7 2 mWm(sup -2)/Tg N yr(sup -1), with some variation among models. Negative net RFs result from reductions in global CH4 (-162.6 plus or minus 2 mWm(sup -2) for a change from 1760 to 1408 ppbv CH4) and regional NMVOC (-0.4 plus or minus 0.2 to 0.7 plus or minus 0.2 mWm(sup -2)/Tg C yr(sup -1) and CO emissions (-0.13 plus or minus 0.02 to -0.15 plus or minus 0.02 mWm(sup-2)/Tg CO yr(sup-1). Including the effect of O3 on CO2 uptake by vegetation likely makes these net RFs more negative by -1.9 to- 5.2 mWm(sup -2)/Tg N yr(sup -1), -0.2 to -0.7 mWm(sup -2)/Tg C yr(sup -1), and -0.02 to -0.05 mWm(sup -2)/ Tg CO yr(sup -1). Net RF impacts reflect the distribution of concentration changes, where RF is affected locally by changes in SO4 (sup -2), regionally to hemispherically by O3, and globally by CH4. Global annual average SO4 2 responses to oxidant changes range from 0.4 plus or minus 2.6 to -1.9 plus or minus 1.3 Gg for NOx reductions, 0.1 plus or minus 1.2 to -0.9 plus or minus 0.8 Gg for NMVOC reductions, and -0.09 plus or minus 0.5 to -0.9 plus or minus 0.8 Gg for CO reductions, suggesting additional research is needed. The 100-year global warming potentials (GWP(sub 100)) are calculated for the global CH4 reduction (20.9 plus or minus 3.7 without stratospheric O3 or water vapor, 24.2 plus or minus 4.2 including those components), and for the regional NOx, NMVOC, and CO reductions (18.7 plus or minus 25.9 to 1.9 plus or minus 8.7 for NOx, 4.8 plus or minus 1.7 to 8.3 plus or minus 1.9 for NMVOC, and 1.5 plus or minus 0.4 to 1.7 plus or minus 0.5 for CO). Variation in GWP(sub 100) for NOx, NMVOC, and CO suggests that regionally specific GWPs may be necessary and could support the inclusion of O3 precursors in future policies that address air quality and climate change simultaneously. Both global net RF and GWP100 are more sensitive to NOx and NMVOC reductions from South Asia than the other three regions.

Fry, Meridith; Naik, Vaishali; West, J. Jason; Schwarzkopf, M. Daniel; Fiore, Arlene M.; Collins, William J.; Dentener, Frank J.; Shindell, Drew T.; Atherton, Cyndi; Bergmann, Daniel; Duncan, Bryan N.; Hess, Peter; MacKenzie, Ian A.; Marmer, Elina; Schultz, Martin G.; Szopa, Sophie; Wild, Oliver; Zeng, Guang

2012-01-01

271

Trends in multi-pollutant emissions from a technology-linked inventory for India: II. Residential, agricultural and informal industry sectors  

NASA Astrophysics Data System (ADS)

Dispersed traditional combustion technologies, characterized by inefficient combustion and significant emissions, are widely used in residential cooking and "informal industries" including brick production, food and agricultural product processing operations like drying and cooking operations related to sugarcane juice, milk, food-grain, jute, silk, tea and coffee. In addition, seasonal agricultural residue burning in field is a discontinuous source of significant emissions. Here we estimate fuel consumption in these sectors and agricultural residue burned using detailed technology divisions and survey-based primary data for 2010 and projected between 1996 and 2015. In the residential sector, a decline in the fraction of solid biomass users for cooking from 79% in 1996 to 65% in 2010 was offset by a growing population, leading to a nearly constant population of solid biomass users, with a corresponding increase in the population of LPG users. Emissions from agriculture followed the growth in agricultural production and diesel use by tractors and pumps. Trends in emissions from the informal industries sector followed those in coal combustion in brick kilns. Residential biomass cooking stoves were the largest contributors to emissions of PM2.5, OC, CO, NMVOC and CH4. Highest emitting technologies of BC were residential kerosene wick lamps. Emissions of SO2 were largely from coal combustion in Bull's trench kilns and other brick manufacturing technologies. Diesel use in tractors was the major source of NOx emissions. Uncertainties in emission estimates were principally from highly uncertain emission factors, particularly for technologies in the informal industries.

Pandey, Apoorva; Sadavarte, Pankaj; Rao, Anand B.; Venkataraman, Chandra

2014-12-01

272

Impact of aviation emissions on the Arctic environment - GEM-AC model simulations  

NASA Astrophysics Data System (ADS)

The continuing decrease of ice cover over the Artic allows for the increase in shipping and industrial activities in the region. These activities lead to the increase of anthropogenic emissions from shipping, prospecting, exploration, and smelting. Emissions from shipping are dominant and their magnitude and impact on the Arctic environment have been addressed in recent publications. The objective of this study is investigate the impact of the increased demand for commercial aviation transport to the Arctic on the air quality near the ground as well as the impact of aviation emissions injected at cruise altitudes (9-11 km ) which in many cases will be above the tropopause. We will present results from the GEM-AC model simulations for several aviation emissions scenarios. GEM-AC (Global Environmental Multiscale model for Atmospheric Chemistry) is a chemical weather model based on the GEM model developed by the Meteorological Service of Canada for operational weather forecasting where air quality, free tropospheric, and stratospheric chemistry process are on-line and interactive. In vertical, the model domain is defined on hybrid levels from the surface to ~60km. The gas-phase chemistry includes detailed reactions of Ox, NOx, HOx, CO, CH4, NMVOCs, halocarbons, ClOx and BrO. Also, the model can address aerosol microphysics and gas-aerosol partitioning. The model will be run on a global variable grid with ~30 km uniform horizontal resolution over the Arctic.

Kaminski, J. W.; Porebska, M.; Semeniuk, K.; Lupu, A.

2013-12-01

273

Aromatic Compounds  

NSDL National Science Digital Library

These organic chemistry quiz questions from the JCE question bank focus on the topic of aromatic compounds. Included in the quiz are questions on nomenclature, synthesis, electrophilic substitution, and huckel's rule. These questions provide great review and practice material for students.

Reich, Ieva

2007-12-03

274

75 FR 77758 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Limiting Emissions of...  

Federal Register 2010, 2011, 2012, 2013

...Delaware; Limiting Emissions of Volatile Organic Compounds From Portable Fuel Containers...to Delaware's regulation for Volatile Organic Compounds (VOC) from Consumer and Commercial...1141--Limiting Emissions of Volatile Organic Compounds from Consumer and...

2010-12-14

275

75 FR 34671 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Limiting Emissions of...  

Federal Register 2010, 2011, 2012, 2013

...Delaware; Limiting Emissions of Volatile Organic Compounds From Consumer Products AGENCY...Delaware concerning the control of volatile organic compounds (VOC). The revision amends...41)--Limiting Emissions of Volatile Organic Compounds from Consumer and...

2010-06-18

276

75 FR 77798 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Limiting Emissions of...  

Federal Register 2010, 2011, 2012, 2013

...Plans; Delaware; Limiting Emissions of Volatile Organic Compounds From Portable Fuel...amendment to Delaware's regulation for Volatile Organic Compounds (VOC) from Consumer...Plans; Delaware; Limiting Emissions of Volatile Organic Compounds from Portable...

2010-12-14

277

Reduction on NOx emissions on urban areas by changing specific vehicle fleets: effects on NO2 and O3 concentration  

NASA Astrophysics Data System (ADS)

The largest amount of NOx emissions in urban areas comes from on-road traffic, which is the largest contributor to urban air pollution (Colvile et al., 2001). Currently different strategies are being tested in order to reduce its effects; many of them oriented to the reduction of the unitary vehicles emissions, by alternative fuels use (such as biofuels, natural gas or hydrogen) or introduction of new technologies (such as hybrid electric vehicles or fuel cells). Atmospheric modelling permits to predict their consequences on tropospheric chemistry (Vautard et al., 2007). Hence, this work assesses the changes on NO2 and O3 concentrations when substituting a 10 per cent of the urban private cars fleets by petrol hybrid electric cars (HEC) or by natural gas cars (NGC) in Madrid and Barcelona urban areas (Spain). These two cities are selected in order to highlight the different patterns of pollutants transport (inland vs. coastal city) and the different responses to emissions reductions. The results focus on a typical summertime episode of air pollution, by means of the Eulerian air quality model ARW- WRF/HERMES/CMAQ, applied with high resolution (1-hr, 1km2) since of the complexity of both areas under study. The detailed emissions scenarios are implemented in the HERMES traffic emissions module, based on the Copert III-EEA/EMEP-CORINAIR (Nztiachristos and Samaras, 2000) methodology. The HEC introduction reduces NOx emissions from on-road traffic in a 10.8 per cent and 8.2 per cent; and the NGC introduction in a 10.3 per cent and 7.8 per cent, for Madrid and Barcelona areas, respectively. The scenarios also affect the NMVOCs reduction (ranging from -3.1 to -6.9 per cent), influencing the tropospheric photochemistry through the NOx/NMVOCs ratio. The abatement of the NO photooxidation but also to the reduction on primary NO2 involves a decrease on NO2 levels centred on urban areas. For example, the NO2 24-hr average concentration in downtown areas reduces up to 8 per cent (-6 ?g m-3 on average). The urban areas are VOC-controlled, therefore the reduction on NOx emissions involves a minor increase on tropospheric O3 concentration (Jiménez and Baldasano, 2004), up to 1.5 per cent at some points. Nevertheless, the O3 precursors reduction has positive effects in the downwind areas affected by the urban plume, slightly reducing the O3 levels, but at the regional scale the reduction applied on urban traffic emissions has negligible effects. Both scenarios tested are very similar in terms of emissions reductions and air quality changes, which means that the NOx/NMVOCs ratio do not involve an O3-sensitivity regime variation among scenarios. The HEC scenario is more effective in reducing NO2 levels in urban areas than the NGC scenario (with maximum reductions affecting a larger area) and involves a larger increase in urban O3 concentration.

Goncalves, M.; Jimenez, P.; Baldasano, J.

2007-12-01

278

Low emission turbo compound engine system  

DOEpatents

A diesel or HHCI engine has an air intake and an exhaust for products of combustion. A pair of turbochargers receive the products of combustion in a series relationship and an exhaust aftertreatment device receive the products of combustion from the downstream turbine. A power turbine receives the output from the exhaust aftertreatment device and an EGR system of the power turbine passes a selected portion of the output to a point upstream of the upstream turbocharger compressor. A device adds fuel to the aftertreatment device to regenerate the particulate filter and the power turbine recoups the additional energy. The power turbine may be used to drive accessories or the prime output of the engine.

Vuk; Carl T. (Denver, IA)

2011-05-31

279

A32A-0126: A BIOGENIC ROLE IN EXPOSURE TO TWO TOXIC COMPOUNDS  

EPA Science Inventory

Biogenic sources play an important role in ozone and particulate concentrations through emissions of volatile organic compounds. The same emissions also contribute to chronic toxic exposures from formaldehyde and acetaldehyde because each compound arises through primary and sec...

280

Transport fate of organic compounds with water through landfills  

Microsoft Academic Search

Hazardous organic compounds have previously been identified in landfill leachates. The emissions of the organic compounds with leachates from landfills are dependent, among other processes, on the water transport through the landfill and the sorption of the compounds to the waste. The purpose of this study was to examine the transport of organic compounds with percolating water through a pilot-scale

Cecilia Öman; Håkan Rosqvist

1999-01-01

281

ORGANIC EMISSIONS FROM MEDICAL WASTE INCINERATION  

EPA Science Inventory

Medical waste contains many substances ranging from pathological material to various chemical compounds. onsequently, the incineration of medical waste may result in the emissions of trace amounts of organic compounds into the environment, if the incinerators are not properly des...

282

40 CFR 52.2350 - Emission inventories.  

...CONTINUED) Utah § 52.2350 Emission inventories. (a) The Governor of the State of Utah submitted the 1990 base year emission inventory of ozone precursors, which are volatile organic compounds, nitrogen oxides, and carbon...

2014-07-01

283

Low emissions diesel fuel  

DOEpatents

A method and matter of composition for controlling NO.sub.x emissions from existing diesel engines. The method is achieved by adding a small amount of material to the diesel fuel to decrease the amount of NO.sub.x produced during combustion. Specifically, small amounts, less than about 1%, of urea or a triazine compound (methylol melamines) are added to diesel fuel. Because urea and triazine compounds are generally insoluble in diesel fuel, microemulsion technology is used to suspend or dissolve the urea or triazine compound in the diesel fuel. A typical fuel formulation includes 5% t-butyl alcohol, 4.5% water, 0.5% urea or triazine compound, 9% oleic acid, and 1% ethanolamine. The subject invention provides improved emissions in heavy diesel engines without the need for major modifications.

Compere, Alicia L. (Knoxville, TN); Griffith, William L. (Oak Ridge, TN); Dorsey, George F. (Farragut, TN); West, Brian H. (Kingston, TN)

1998-01-01

284

Low emissions diesel fuel  

DOEpatents

A method and matter of composition for controlling NO{sub x} emissions from existing diesel engines. The method is achieved by adding a small amount of material to the diesel fuel to decrease the amount of NO{sub x} produced during combustion. Specifically, small amounts, less than about 1%, of urea or a triazine compound (methylol melamines) are added to diesel fuel. Because urea and triazine compounds are generally insoluble in diesel fuel, microemulsion technology is used to suspend or dissolve the urea or triazine compound in the diesel fuel. A typical fuel formulation includes 5% t-butyl alcohol, 4.5% water, 0.5% urea or triazine compound, 9% oleic acid, and 1% ethanolamine. The subject invention provides improved emissions in heavy diesel engines without the need for major modifications.

Compere, A.L.; Griffith, W.L.; Dorsey, G.F.; West, B.H.

1998-05-05

285

Intermetallic Compounds  

NASA Astrophysics Data System (ADS)

We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- ?V-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 ?.

Takagiwa, Y.; Matsuura, Y.; Kimura, K.

2014-06-01

286

Environmental effects of the recent emission changes in China: implications for particulate matter pollution and soil acidification  

NASA Astrophysics Data System (ADS)

Driven by a rapid increase of energy consumption and emerging pollution control policies, air pollutant emissions have changed dramatically in China during 2005-2010. This study developed a multi-pollutant emission inventory, and used the community multi-scale air quality (CMAQ) modeling system to evaluate the impact of the emission changes on particulate matter pollution and soil acidification. During 2005-2010, the emissions of SO2, PM10 and PM2.5 decreased by 14.9%, 15.1% and 11.7%, respectively. In contrast, the emissions of NOX, NMVOC and NH3 increased by 33.8%, 21.0% and 10.4%, respectively. The emission trends differed notably in different regions. Driven by emission changes, PM2.5 concentrations decreased by 2-17 ?g m-3 in most of the North China Plain, the Yangtze River Delta and the Pearl River Delta, while increasing by 4.5-16 ?g m-3 in most of the Sichuan Basin and Eastern Hubei. The changes of PM2.5 emissions led to the decline of primary PM2.5 concentrations in most of Eastern China. As an effect solely of emission changes, nitrate concentrations increased across most of China; sulfate concentrations decreased in most of Eastern China, with the largest reduction in the North China Plain, while they increased in the Sichuan Basin and parts of the Pearl River Delta and Eastern Hubei. The concentrations of secondary inorganic aerosols (SIA) and the extinction coefficient increased in most of China, especially in the Sichuan Basin and Eastern Hubei, implying that the NOX and NH3 emissions should be reduced simultaneously in China. Combining the acidification effects of S and N, the exceedance of critical loads decreased across the country, but increased in the Sichuan Basin, the Pearl River Delta and Eastern Hubei, where the soil acidification was the most serious. Different control policies need to be implemented in different regions.

Zhao, Bin; Wang, Shuxiao; Dong, Xinyi; Wang, Jiandong; Duan, Lei; Fu, Xiao; Hao, Jiming; Fu, Joshua

2013-06-01

287

Bismaleimide compounds  

DOEpatents

Bismaleimides of the formula shown in the diagram wherein R[sub 1] and R[sub 2] each independently is H, C[sub 1-4]-alkyl, C[sub 1-4]-alkoxy, Cl or Br, or R[sub 1] and R[sub 2] together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R[sub 1] and R[sub 2] are not t-butyl or t-butoxy; X is O, S or Se; n is 1--3; and the alkylene bridging group, optionally, is substituted by 1--3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

Adams, J.E.; Jamieson, D.R.

1986-01-14

288

Bismaleimide compounds  

DOEpatents

Bismaleimides of the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, C1 or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

Adams, Johnnie E. (Grandview, MO); Jamieson, Donald R. (Merriam, KS)

1986-01-14

289

Low volatile organic compound paints  

SciTech Connect

Increasingly stringent air emission standards in various states has dictated the elimination of engineering finishes which are derived from high volatile organic compound (VOC) paint chemistries. In July 1989, Allied-Signal, Inc., Kansas City Division, Kansas City, Missouri, voluntarily closed its paint facility, due to non-compliance with local air emission standards. The following details the materials selection and evaluations which led to current processing using low VOC paints, which permitted the Allied Signal, Inc., paint facility to achieve compliance and resume operations. 1 tab.

Martinez, F.E.

1991-01-01

290

GLOBAL ORGANIC EMISSIONS FROM VEGETATION  

EPA Science Inventory

The book chapter discusses several aspects of biogenic volatile organic compound (BVOC) emissions from vegetation. It begins with a section on emission measurements that includes a brief history of enclosure and above-canopy flux measurements as well as a discussion of existing d...

291

Synthesis of Fluorinated ZDDP Compounds  

Microsoft Academic Search

Volatile degradation products of zinc dialkyl dithio phosphate (ZDDP) composed of phosphorus and sulfur compounds reduce the\\u000a efficiency of catalytic converters resulting in harmful emissions. A unique way of reducing ZDDP level while maintaining good\\u000a antiwear performance has been achieved by reacting a novel additive FeF3 with ZDDP. The objective of this research is to examine the chemical interactions between

Kajal Parekh; Xin Chen; Pranesh B. Aswath

2009-01-01

292

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

Code of Federal Regulations, 2013 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...

2013-07-01

293

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

294

Emission reduction  

NASA Technical Reports Server (NTRS)

Control of the gaseous pollutant emissions of aircraft engines is considered in terms of the emission standards for six classes of aircraft engines. Emphasis is placed on combustor design concepts to significantly reduce emissions levels and lean-burning techniques to lower flame temperature, to reduce the oxides of nitrogen in the gaseous emissions.

Petrash, D. A.; Diehl, L. A.; Jones, R. E.; Mularz, E. J.

1979-01-01

295

Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations  

Microsoft Academic Search

An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road

Wolfgang F. Rogge; Lynn M. Hildemann; Monica A. Mazurek; Glen R. Cass; Bernd R. T. Simoneit

1996-01-01

296

Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations  

Microsoft Academic Search

An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped diesel trucks, paved road dust,

Wolfgang F. Rogge; Lynn M. Hildemann; Monica A. Mazurek; Glen R. Cass; Bernd R. T. Simoneit

1996-01-01

297

Luminescence of Lanthanide-Dimethyl Sulfoxide Compound Solutions  

SciTech Connect

Dimethyl sulfoxide (DMSO) has the ability to penetrate living tissues without causing significant damage. Of foremost importance to our understanding of the possible functions of DMSO in biological systems is its ability to replace some of the water molecules associated with the cellular constituents, or to affect the structure of the omnipresent water. Luminescence probes have been widely used for biological studies such as labeling, imaging and detection. Luminescence probes formed in DMSO may find new applications. Here, luminescence compounds formed by refluxing lanthanide nitrates of Ce, La, Tb, Yb, Nd, Gd and Eu in DMSO are reported and their luminescence properties investigated. Based on their luminescence spectral properties, the compounds can be classified into four classes. For compounds-I with Yb, Ce, and La, the excitation and emission spectra are very broad and their excitation or emission peaks are shifted to longer wavelengths when the monitored emission or excitation wavelength is longer . For compounds-II with Gd and Nd, both the excitation and emission spectra are very broad but their emission wavelengths change little at different excitation wavelengths. For Tb-DMSO as compound-III, both the typical emissions from the f - f transitions of Tb3+ and a broad emission at 445 nm are observed. At low temperatures of reaction, the f - f emissions are dominant, while at high temperatures such as 180 oC of reaction, the broad emission at 445 nm is dominant. For compound-IV with Eu-DMSO compounds, the dominant emissions are from the f - f transitions of Eu3+ and only a weak broad emission is observed, which is likely from the d - f transition of Eu2+ rather than from the metal to ligand charge transfer states.

Yao, Mingzhen; Li, Yuebin; Hossu, Marius; Joly, Alan G.; Liu, Zhongxin; Liu, Zuli; Chen, Wei

2011-08-04

298

Biomass burning in Asia : annual and seasonal estimates and atmospheric emissions.  

SciTech Connect

Estimates of biomass burning in Asia are developed to facilitate the modeling of Asian and global air quality. A survey of national, regional, and international publications on biomass burning is conducted to yield consensus estimates of 'typical' (i.e., non-year-specific) estimates of open burning (excluding biofuels). We conclude that 730 Tg of biomass are burned in a typical year from both anthropogenic and natural causes. Forest burning comprises 45% of the total, the burning of crop residues in the field comprises 34%, and 20% comes from the burning of grassland and savanna. China contributes 25% of the total, India 18%, Indonesia 13%, and Myanmar 8%. Regionally, forest burning in Southeast Asia dominates. National, annual totals are converted to daily and monthly estimates at 1{sup o} x 1{sup o} spatial resolution using distributions based on AVHRR fire counts for 1999--2000. Several adjustment schemes are applied to correct for the deficiencies of AVHRR data, including the use of moving averages, normalization, TOMS Aerosol Index, and masks for dust, clouds, landcover, and other fire sources. Good agreement between the national estimates of biomass burning and adjusted fire counts is obtained (R{sup 2} = 0.71--0.78). Biomass burning amounts are converted to atmospheric emissions, yielding the following estimates: 0.37 Tg of SO{sub 2}, 2.8 Tg of NO{sub x}, 1100 Tg of CO{sub 2}, 67 Tg of CO, 3.1 Tg of CH{sub 4}, 12 Tg of NMVOC, 0.45 Tg of BC, 3.3 Tg of OC, and 0.92 Tg of NH{sub 3}. Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of {+-}65% for CO{sub 2} emissions in Japan to a high of {+-}700% for BC emissions in India.

Streets, D. G.; Yarber, K. F.; Woo, J.-H.; Carmichael, G. R.; Decision and Information Sciences; Univ. of Iowa

2003-10-15

299

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...

300

Compounding in Ukraine.  

PubMed

Pharmaceutical compounding in modern Ukraine has a rich history and goes back to ancient times. Today in the Ukraine, there is a revival of compounding practice, the opening of private compounding pharmacies, updating of legislative framework and requirements of the State Pharmacopeia of Ukraine for compounding preparations, and the introduction of Good Pharmaceutical Practice. PMID:23696172

Zdoryk, Oleksandr A; Georgiyants, Victoriya A; Gryzodub, Oleksandr I; Schnatz, Rick

2013-01-01

301

Sanskrit Compound Processor  

NASA Astrophysics Data System (ADS)

Sanskrit is very rich in compound formation. Typically a compound does not code the relation between its components explicitly. To understand the meaning of a compound, it is necessary to identify its components, discover the relations between them and finally generate a paraphrase of the compound. In this paper, we discuss the automatic segmentation and type identification of a compound using simple statistics that results from the manually annotated data.

Kumar, Anil; Mittal, Vipul; Kulkarni, Amba

302

INFLUENCE OF BIOGENIC EMISSIONS ESTIMATES ON OZONE PRECURSORCONTROL REQUIREMENTS FOR ATLANTA  

EPA Science Inventory

Emission estimates of volatile organic compounds (VOC) from naturalsources (biogenic emissions) are comparable to emissions fromanthropogenic sources in some regions of the U.S. esults from aprevious modeling study indicated that inclusion of biogenicemissions can substantially i...

303

Emissions from syngas combustion  

SciTech Connect

Gasification technology has matured to the point that previously-held hesitations regarding performance and availability have given way to acceptance of the technology for energy generation. Indeed, the past few years have seen a significant increase in the number of gasifiers installed for generation of power and heat, and the number of installations is expected to increase dramatically over the next several decades as demand for efficient and environmentally sound energy generation increases. It is valuable to consider the environmental impact of this new generation of energy production systems, specifically release of gaseous emissions from combustion of the synthesis gas produced by gasification. Emissions from syngas combustion in turbines, engines and boilers are discussed in this review. The types of emissions considered include the unburned fuel components and partially oxidized species, nitrogen and sulfur-containing gases, volatile organic compounds, and other trace elements. Combustion of synthesis gas, in general, produces lower emissions for heat and power generation than conventional liquid and solid fuels. The composition of the syngas strongly influences the level of emissions. Hydrogen and carbon monoxide in synthesis gases results in elevated combustion temperature that facilitates the thermal formation of NO and NO{sub 2}. In contrast, higher temperatures promote complete combustion and reduce the emission of organic volatiles, which are formed mainly from minor fractions of hydrocarbons in synthesis gases. Particulate matter, metallic compounds and other undesired pollutants are usually removed before firing synthesis gases for heat and power production. Therefore, integrated gasification and combined cycle systems are more environmentally friendly than conventional power generation systems.

Whitty, K.J.; Zhang, H.R.; Eddings, E.G. [University of Utah, Salt Lake City, UT (United States). Inst. for Clean & Secure Energy

2008-07-01

304

Focused ion beam and field-emission microscopy of metallic filaments in memory devices based on thin films of an ambipolar organic compound consisting of oxadiazole, carbazole, and fluorene units  

USGS Publications Warehouse

We report on the mechanism of operation of organic thin film resistive memory architectures based on an ambipolar compound consisting of oxadiazole, carbazole, and fluorene units. Cross-sections of the devices have been imaged by electron microscopy both before and after applying a voltage. The micrographs reveal the growth of filaments, with diameters of 50?nm–100?nm, on the metal cathode. We suggest that these are formed by the drift of aluminium ions from the anode and are responsible for the observed switching and negative differential resistance phenomena in the memory devices.

Pearson, Christopher; Bowen, Leon; Lee, Myung Won; Fisher, Alison L.; Linton, Katherine E.; Bryce, Martin R.; Petty, Michael C.

2013-01-01

305

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

306

40 CFR 52.2086 - Emission inventories.  

...emission inventory requirement of section 182(a)(1) of the Clean Air Act, as amended...The inventory is for the ozone precursors which are volatile organic compounds...serious and includes the entire state of Rhode Island. (d)...

2014-07-01

307

Dinitroso and polynitroso compounds  

PubMed Central

The growing interest in the chemistry of C-nitroso compounds (RN=O; R = alkyl or aryl group) is due in part to the recognition of their participation in various metabolic processes of nitrogen-containing compounds. C-Nitroso compounds have a rich organic chemistry in their own right, displaying interesting intra- and intermolecular dimerization processes and addition reactions with unsaturated compounds. In addition, they have a fascinating coordination chemistry. While most of the attention has been directed towards C-nitroso compounds containing a single –NO moiety, there is an emerging area of research dealing with dinitroso and polynitroso compounds. In this critical review, we present and discuss the synthetic routes and properties of these relatively unexplored dinitroso and polynitroso compounds, and suggest areas of further development involving these compounds. (126 references.) PMID:16100619

Gowenlock, Brian G.; Richter-Addo, George B.

2005-01-01

308

Compounds affecting cholesterol absorption  

NASA Technical Reports Server (NTRS)

A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

2004-01-01

309

MANUAL METHOD FOR MEASUREMENT OF REDUCED SULFUR COMPOUNDS  

EPA Science Inventory

A manual method for measuring reduced sulfur compounds in Kraft pulp mill and sulfur recovery plant emissions was evaluated. The method involves removing SO2 from the gas stream (if present) with a citric acid-potassium citrate buffer, that passes reduced sulfur compounds; therma...

310

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...

311

Emission Database for Global Atmospheric Research (EDGAR).  

ERIC Educational Resources Information Center

Presents the objective and methodology chosen for the construction of a global emissions source database called EDGAR and the structural design of the database system. The database estimates on a regional and grid basis, 1990 annual emissions of greenhouse gases, and of ozone depleting compounds from all known sources. (LZ)

Olivier, J. G. J.; And Others

1994-01-01

312

Emission estimates for air pollution transport models.  

SciTech Connect

The results of studies of energy consumption and emission inventories in Asia are discussed. These data primarily reflect emissions from fuel combustion (both biofuels and fossil fuels) and were collected to determine emissions of acid-deposition precursors (SO{sub 2} and NO{sub x}) and greenhouse gases (CO{sub 2} CO, CH{sub 4}, and NMHC) appropriate to RAINS-Asia regions. Current work is focusing on black carbon (soot), volatile organic compounds, and ammonia.

Streets, D. G.

1998-10-09

313

Vibro-acoustography and Multifrequency Image Compounding  

PubMed Central

Vibro-acoustography is an ultrasound based imaging modality that can visualize normal and abnormal soft tissue through mapping the acoustic response of the object to a harmonic radiation force at frequency ?f induced by focused ultrasound. In this method, the ultrasound energy is converted from high ultrasound frequencies to a low acoustic frequency (acoustic emission) that is often two orders of magnitude smaller than the ultrasound frequency. The acoustic emission is normally detected by a hydrophone. Depending on the setup, this low frequency sound may reverberate by object boundaries or other structures present in the acoustic paths before it reaches the hydrophone. This effect produces an artifact in the image in the form of gradual variations in image intensity that may compromise image quality. The use of tonebursts with finite length yields acoustic emission at ?f and at sidebands centered about ?f. Multiple images are formed by selectively applying bandpass filters on the acoustic emission at ?f and the associated sidebands. The data at these multiple frequencies are compounded through both coherent and incoherent processes to reduce the acoustic emission reverberation artifacts. Experimental results from a urethane breast phantom are described. The coherent and incoherent compounding of multifrequency data show, both qualitatively and quantitatively, the efficacy of this reverberation reduction method. This paper presents theory describing the physical origin of this artifact and use of image data created using multifrequency vibro-acoustography for reducing reverberation artifacts. PMID:21377181

Urban, Matthew W.; Alizad, Azra; Fatemi, Mostafa

2011-01-01

314

Projections of air pollutant emissions and its impacts on regional air quality in China in 2020  

NASA Astrophysics Data System (ADS)

Anthropogenic emissions of air pollutants in China influence not only local and regional environments but also the global atmospheric environment; therefore, it is important to understand how China's air pollutant emissions will change and how they will affect regional air quality in the future. Emission scenarios in 2020 were projected using forecasts of energy consumption and emission control strategies based on emissions in 2005, and on recent development plans for key industries in China. We developed four emission scenarios: REF[0] (current control legislations and implementation status), PC[0] (improvement of energy efficiencies and current environmental legislation), PC[1] (improvement of energy efficiencies and better implementation of environmental legislation), and PC[2] (improvement of energy efficiencies and strict environmental legislation). Under the REF[0] scenario, the emission of SO2, NOx, VOC and NH3 will increase by 17%, 50%, 49% and 18% in 2020, while PM10 emissions will be reduced by 10% over East China, compared to that in 2005. In PC[2], sustainable energy polices will reduce SO2, NOx and PM10 emissions by 4.1 Tg, 2.6 Tg and 1.8 Tg, respectively; better implementation of current control policies will reduce SO2, NOx and PM10 emission by 2.9 Tg, 1.8 Tg, and 1.4 Tg, respectively; strict emission standards will reduce SO2, NOx and PM10 emissions by 3.2 Tg, 3.9 Tg, and 1.7 Tg, respectively. Under the PC[2] scenario, SO2 and PM10 emissions will decrease by 18% and 38%, while NOx and VOC emissions will increase by 3% and 8%, compared to that in 2005. Future air quality in China was simulated using the Community Multi-scale Air Quality Model (CMAQ). Under REF[0] emissions, compared to 2005, the surface concentrations of SO2, NO2, hourly maximum ozone in summer, PM2.5, total sulfur and nitrogen depositions will increase by 28%, 41%, 8%, 8%, 19% and 25%, respectively, over east China. Under the PC[2] emission scenario, the surface concentrations of SO2, PM2.5, total sulfur depositions will decrease by 18%, 16% and 15%, respectively, and the surface concentrations of NO2, nitrate, hourly maximum ozone in summer, total nitrogen depositions will be kept as 2005 level, over east China. The individual impacts of SO2, NOx, NH3, NMVOC and primary PM emission changes on ozone and PM2.5 concentrations have been analyzed using sensitivity analysis. The results suggest that NOx emission control need to be enhanced during the summertime to obtain both ozone and PM2.5 reduction benefits. NH3 emission controls should also be considered in order to reduce both nitrate concentration and total nitrogen deposition in the future.

Xing, J.; Wang, S. X.; Chatani, S.; Zhang, C. Y.; Wei, W.; Hao, J. M.; Klimont, Z.; Cofala, J.; Amann, M.

2011-04-01

315

Nuclear evaporation process with simultaneous multiparticle emission  

E-print Network

The nuclear evaporation process is reformulated by taking into account simultaneous multiparticle emission from a hot compound nucleus appearing as an intermediate state in many nuclear reaction mechanisms. The simultaneous emission of many particles is particularly relevant for high excitation energy of the compound nucleus.These channels are effectively open in competition with the single particle emissions and fission in this energy regime. Indeed, the inclusion of these channels along the decay evaporating chain shows that the yield of charged particles and occurrence of fission are affected by these multiparticle emission processes of the compounded nucleus, when compared to the single sequential emission results. The effect also shows a qualitative change in the neutron multiplicity of different heavy compound nucleus considered. This should be an important aspect for the study of spallation reaction in Acceleration Driven System (ADS) reactors. The majority of neutrons generated in these reactions come from the evaporation stage of the reaction, the source of neutron for the system. A Monte Carlo simulation is employed to determine the effect of these channels on the particle yield and fission process. The relevance of the simultaneous particle emission with the increasing of excitation energy of the compound nucleus is explicitly shown.

Leonardo P. G. De Assis; Sergio B. Duarte; Bianca M. Santos

2012-08-07

316

XAFS Model Compound Library  

DOE Data Explorer

The XAFS Model Compound Library contains XAFS data on model compounds. The term "model" compounds refers to compounds of homogeneous and well-known crystallographic or molecular structure. Each data file in this library has an associated atoms.inp file that can be converted to a feff.inp file using the program ATOMS. (See the related Searchable Atoms.inp Archive at http://cars9.uchicago.edu/~newville/adb/) This Library exists because XAFS data on model compounds is useful for several reasons, including comparing to unknown data for "fingerprinting" and testing calculations and analysis methods. The collection here is currently limited, but is growing. The focus to date has been on inorganic compounds and minerals of interest to the geochemical community. [Copied, with editing, from http://cars9.uchicago.edu/~newville/ModelLib/

Newville, Matthew

317

Preparation of uranium compounds  

DOEpatents

UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

2013-02-19

318

Unburned lubricant produces 60%90% of organic carbon emissions.  

E-print Network

as the most polluting of conventional petroleum-based fuels, emissions from gasoline engines can more of those currently on the market · Gasoline containing no ethanol, E10, Texas-mandated low-emission diesel contributions of fuels and engine lubricating oil on PM and semi-volatile organic compound emissions from in-use

319

Applications of Satellite Remote Sensing Data for Biogenic Emission Estimates in Southeastern Texas  

Microsoft Academic Search

Biogenic hydrocarbons, including isoprene, monoterpenes, and oxygenated compounds, are emitted in substantial quantities by vegetation and dominate the overall volatile organic compound emission inventory in Southeastern Texas. Spatial distributions of biogenic emissions in Texas are heterogeneous, and biogenic emission processes are affected by the characterization of land cover, leaf area index, drought stress, and surface temperatures. On a regional scale,

M. S. Feldman; T. Howard; G. Mullins; E. McDonald-Buller; D. T. Allen

2007-01-01

320

Analysis of volatile organic compounds from illicit cocaine samples  

SciTech Connect

Detection of illicit cocaine hydrochloride shipments can be improved if there is a greater understanding of the identity and quantity of volatile compounds present. This study provides preliminary data concerning the volatile organic compounds detected in a limited Set of cocaine hydrochloride samples. In all cases, cocaine was one of the major volatile compounds detected. Other tropeines were detected in almost all samples. Low concentrations of compounds that may be residues of processing solvents were observed in some samples. The equilibrium emissivity of. cocaine from cocaine hydrochloride was investigated and a value of 83 parts-per-trillion was determined.

Robins, W.H.; Wright, B.W.

1994-07-01

321

Analyzing Cranberry Bioactive Compounds  

Microsoft Academic Search

There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit—the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a

J. Côté; S. Caillet; G. Doyon; J.-F Sylvain; M. Lacroix

2010-01-01

322

Toxicity of nitroaromatic compounds  

SciTech Connect

The contents of this book include: Sex, Strain, and Species Differences in the Response of Rodents to Nitrobenzene Vapors; The Hepatocarcinogenicity of Dinitrotoluenes; Free Radical Mechanism of Nitroreductase; Use of an In Vivo DNA Repair Assay in the Study of Genotoxicity of Nitroaromatic Compounds; and Possible Models for Risk Assessment of Nitroaromatic Compounds.

Rickert, D.E.

1985-01-01

323

NEAR-REAL-TIME MEASUREMENT OF TRACE VOLATILE ORGANIC COMPOUNDS FROM COMBUSTION PROCESSES USING AN ON-LINE GAS CHROMATOGRAPH  

EPA Science Inventory

The U.S. EPA's current regulatory approach for combustion and incineration sources emphasizes the use of real-time continuous emission monitors (CEMs) for particulate, Metals, and volatile, semivolatile, and of nonvolatile organic compounds to monitor source emissions. Currently...

324

Monoterpene emission from ponderosa pine  

NASA Technical Reports Server (NTRS)

We explore the variability in monoterpene emissions from ponderosa pine beyond that which can be explained by temperature alone. Specifically, we examine the roles that photosynthesis and needle monoterpene concentrations play in controlling emissions. We measure monoterpene concentrations and emissions, photosynthesis, temperature, and light availability in the late spring and late summer in a ponderosa pine forest in central Oregon. We use a combination of measurements from cuvettes and Teflon bag enclosures to show that photosynthesis is not correlated with emissions in the short term. We also show that needle monoterpene concentrations are highly correlated with emissions for two compounds, alpha-pinene and beta-pinene, but that Delta-carene concentrations are not correlated with emissions. We suggest that direct effects of light and photosynthesis do not need to be included in emission algorithms. Our results indicate that the role of needle concentration bears further investigation; our results for alpha-pinene and beta-pinene are explainable by a Raoult's law relationship, but we cannot yet explain the cause of our results with Delta-carene.

Lerdau, Manual; Dilts, Stephen B.; Westberg, Hal; Lamb, Brian K.; Allwine, Eugene J.

1994-01-01

325

Edheads: The Compound Machine  

NSDL National Science Digital Library

This resource is a collection of interactive animations designed to help kids learn how forces and simple machines can work together to create the compound machine. Child-centered animated activities enhance understanding of how compound machines function and how they are differentiated from simple machines. Additionally the site includes a glossary of important terms, lesson plans, a teacher's guide and information about professionals who work with compound machines. This page is part of a larger collection of animated education resources for the elementary level.

2007-09-18

326

Heart testing compound  

DOEpatents

The compound 15-(p-[.sup.125 I]-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

Knapp, Jr., Furn F. (Oak Ridge, TN); Goodman, Mark M. (Knoxville, TN)

1985-01-01

327

Heart testing compound  

DOEpatents

The compound 15-(p-(/sup 125/I)-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

Knapp, F.F. Jr.; Goodman, M.M.

1983-06-29

328

Ringed-Carbon Compounds  

NSDL National Science Digital Library

In this interactive activity adapted from NOVA, learn about alkaloids and steroids, both examples of compounds with carbon rings. Short videos with interviews,animations, and photographs are featured.

Foundation, Wgbh E.

2007-02-12

329

Sulfur emissions from Mt. Etna  

Microsoft Academic Search

In the course of three measuring trips to the Mt. Etna volcano (Sicily), field measurements and measurements by aircraft were carried out in the plume of the volcano to determine the concentration distributions and emission rates for the sulfur compounds H2S, SO2, and SO42-. Furthermore, the removal of H2S and SO2 and the production of SO42- in the dispersing plume

Wolfgang Jaeschke; Harald Berresheim; Hans-W. Georgii

1982-01-01

330

Seasonal monoterpene and sesquiterpene emissions from Pinus taeda and Pinus virginiana  

EPA Science Inventory

Seasonal volatile organic compound emission data from loblolly pine (Pinus taeda) and Virginia pine (Pinus virginiana) were collected using branch enclosure techniques in Central North Carolina, USA. Pinus taeda monoterpene emission rates were at least ten times higher than oxyge...

331

78 FR 34911 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Low Emission Vehicle...  

Federal Register 2010, 2011, 2012, 2013

...incorporates by reference California's second generation Low Emission Vehicle (LEVII) program...reduce emissions of nitrogen oxide (NO X ) and volatile organic compound...Maryland has adopted California's second generation of LEV program rules, or LEV II,...

2013-06-11

332

Incorporating Undesirable Outputs into Malmquist TFP Index: Environmental Performance Growth of Chinese Coal-Fired Power Plants  

E-print Network

of Swedish pharmacies: 1/ 21 1 1 1 1 1 1 1 1 1 1 ( , , ) ( , , ) ( , , , , , ) ( , , ) ( , , ) ( ) t t t t t t t t Fare t t t t t t a t t t t t t t t Fare a D x y a D x y a M x y a x y a D x y a D x y a M... organic compounds (NMVOC). An accurate estimate of these emissions depends on having knowledge of several interrelated factors, including combustion conditions, technology, and emission control policies, as well as fuel characteristics. In general...

Yang, Hongliang; Pollitt, Michael G.

333

Assimilating chemical compound with a regional chemical model  

NASA Astrophysics Data System (ADS)

To constrain the sink and source of the chemical compounds at surface during model simulation, chemical compound assimilation with Local Ensemble Transform Kalman Filter has been implemented for the WRFChemT model. The WRFChemT model has the chemical components coupled with the regional meteorological model with specified surface fluxes of the chemical compounds. Previous related studies on chemical assimilation have been focusing on the impact on the global atmospheric models (Kang et al. 2010 and Liu et al. 2010). In this study, we investigate the regional impact of the chemical compounds. Different from the applications of EnKF to weather prediction, the interactions between meteorological variables and surface emission of the chemical compounds are indirect and bridged through the tracer variables. How to construct the coupled atmospheric-chemical multi-variate error covariance based on the ensemble becomes the challenge of this new assimilation system. In this work, we perform OSSE experiments to evaluate the performance of the new assimilation system and also to investigate the strategies for assimilating the chemical compounds with LETKF. Corrections for surface flux can be obtained from adequately using observations of meteorology and chemical compounds with the ensemble-based multivariable covariance. Results suggest that meteorological dynamics plays a crucial role in adjusting the total mass of the chemical compounds, which in turns affect the retrieval of the surface emission.

Yang, S.; Liang, M.; Tseng, Y.

2011-12-01

334

Nonpost mold cure compound  

NASA Astrophysics Data System (ADS)

The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

Hirata, Akihiro

1997-08-01

335

Determination of organic emissions from new carpeting  

SciTech Connect

New carpeting has been the source of a number of indoor air health and odor complaints. Investigations of a variety of carpet samples have shown that there is a diversity of organic emissions among carpet types; some of the compounds found have been listed in the NIOSH Registry of Toxic Effects of Chemical Substances. The paper describes two complementary analytical methods for screening carpet samples: a 'headspace' method for volatile emissions and a Soxhlet extraction method using methylene chloride for the semi-volatile and non-volatile compounds. The analytical results from seven carpet types are presented with special emphasis on the compound 4-phenylcyclohexene, one of the causes of 'new carpet smell,' which has also been anectdotally linked to adverse short term health effects. Other compounds of possible interest that were found include dichlorobenzene, bis(2-ethylhexyl)-phthalate, triethyl phosphate, epsilon-caprolactam, and methylene-bis(4-isocyanatobenzene).

Pleil, J.D.; Whiton, R.S.

1990-01-01

336

Compound management beyond efficiency.  

PubMed

Codeveloping alongside chemistry and in vitro screening, compound management was one of the first areas in research recognizing the need for efficient processes and workflows. Material management groups have centralized, automated, miniaturized and, importantly, found out what not to do with compounds. While driving down cost and improving quality in storage and processing, researchers still face the challenge of interfacing optimally with changing business processes, in screening groups, and with external vendors and focusing on biologicals in many companies. Here we review our strategy to provide a seamless link between compound acquisition and screening operations and the impact of material management on quality of the downstream processes. Although this is driven in part by new technologies and improved quality control within material management, redefining team structures and roles also drives job satisfaction and motivation in our teams with a subsequent positive impact on cycle times and customer feedback. PMID:19502566

Burr, Ian; Winchester, Toby; Keighley, Wilma; Sewing, Andreas

2009-06-01

337

Metalloid compounds as drugs  

PubMed Central

The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O’-)tellurate (AS101) may be a promising agent for the treatment of Parkinson’s disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents. PMID:24019824

Sekhon, B. S.

2013-01-01

338

Sulfur compounds in coal  

NASA Technical Reports Server (NTRS)

The literature on the chemical structure of the organic sulfur compounds (or functional groups) in coal is reviewed. Four methods were applied in the literature to study the sulfur compounds in coal: direct spectrometric and chemical analysis, depolymerization in drastic conditions, depolymerization in mild conditions, and studies on simulated coal. The data suggest that most of the organic sulfur in coal is in the form of thiophenic structures and aromatic and aliphatic sulfides. The relative abundance of the sulfur groups in bituminous coal is estimated as 50:30:20%, respectively. The ratio changes during processing and during the chemical analysis. The main effects are the transformation during processing of sulfides to the more stable thiophenic compounds and the elimination of hydrogen sulfide.

Attar, A.; Corcoran, W. H.

1977-01-01

339

Microoptical compound lens  

DOEpatents

An apposition microoptical compound lens comprises a plurality of lenslets arrayed around a segment of a hollow, three-dimensional optical shell. The lenslets collect light from an object and focus the light rays onto the concentric, curved front surface of a coherent fiber bundle. The fiber bundle transports the light rays to a planar detector, forming a plurality of sub-images that can be reconstructed as a full image. The microoptical compound lens can have a small size (millimeters), wide field of view (up to 180.degree.), and adequate resolution for object recognition and tracking.

Sweatt, William C. (Albuquerque, NM); Gill, David D. (Albuquerque, NM)

2007-10-23

340

Compounding practices in Iran.  

PubMed

This article has been presented by pharmacists of the Razi Hospital Pharmacy, which is located within the Dermatology Center of Tehran University of Medical Sciences in Tehran, Iran, and by members of the staff at the Tehran University of Medical Sciences. Discussed within this article are the legalization and regulation of pharmaceutical compounding in Iran, the restrictions on pharmaceutical compounding, the general equipment used in Iran pharmacies, beyond-use dating/expiration dating, the required pharmacy education, as well as information related specifically to Razi Hospital Pharmacy. PMID:24881113

Goodarzi, Navid; Niknam, Somayeh; Akbarzadeh, Tahmineh; Gholami, Kheirollah

2014-01-01

341

Study of building material emissions and indoor air quality  

E-print Network

Building materials and furnishings emit a wide variety of indoor pollutants, such as volatile organic compounds (VOCs). At present, no accurate models are available to characterize material emissions and sorption under ...

Yang, Xudong, 1966-

1999-01-01

342

CONTROL TECHNOLOGIES FOR FUGITIVE VOC EMISSIONS FROM CHEMICAL PROCESSES  

EPA Science Inventory

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

343

ASSESSMENT OF VOC EMISSIONS FROM FIBERGLASS BOAT MANUFACTURING  

EPA Science Inventory

The report presents an assessment of volatile organic compound (VOC) emissions from fiberglass boat manufacturing. Description of the industry structure is presented, including estimates of the number of facilities, their size, and geographic distribution. The fiberglass boat m...

344

ASSESSMENT OF VOC EMISSIONS FROM FIBERGLASS BOAT MANUFACTURING  

EPA Science Inventory

The report presents an assessment of volatile organic compound (VOC) emissions from fiberglass boat manufacturing. escription of the industry structure is presented, including estimates of the number of facilities, their size, and geographic distribution. he fiberglass boat manuf...

345

A Novel New Approach to VOC and HAP Emission Control  

E-print Network

HAP (Hazardous Air Pollutant) and VOC (Volatile Organic Compound) thermal emission control devices (ECD) usually require large amounts of energy to operate. They also require large capital investments in heat recovery options and large amounts...

McGinness, M.

346

Caulking compound poisoning  

MedlinePLUS

... substances used to seal cracks and holes around windows and other openings. Caulking compound poisoning occurs when someone swallows these substances. This is for information only and not for use in the treatment or management of an actual poison exposure. If ...

347

Compound Poisson process approximation  

Microsoft Academic Search

Compound Poisson processes are often useful as approximate models, when describing the occurrence of rare events. In this paper, we develop a method for showing how close such approximations are. Our approach is to use Stein's method directly, rather than by way of declumping and a marked Poisson process; this has conceptual advantages, but entails technical difficulties. Several applications are

A. D. Barbour; Marianne Månsson

2002-01-01

348

The Onium Compounds  

NASA Astrophysics Data System (ADS)

The onium salts are of a big interest for theoretical and structural chemistry, and for organic synthesis. Some representatives of the group (e.g. ammonium salts) were known from the oldest times. Many onium salts are met the nature: ammonium salts (either as inorganic salts, and organic derivatives, e.g. aminoacids, salts of biogenic amines and alkaloids, etc.); oxonium salts (plant pigments as anthocyans are organic oxonium compounds), etc. In 1894 C. Hartmann and V. Meyer prepared the first iodonium salts - 4-iododiphenyliodonium hydrogensulfate and diphenyliodonium salts, and suggested the ending -onium for all compounds with properties similar to those of ammonium salts. Nowadays onium compounds of almost all nonmetals are synthesised and studied. A great variety of physical methods: diffraction (e.g. XRD) and spectral methods (IR-, NMR-, and UV-spectra), as well as the chemical properties and methods of preparation of onium salts have been used in determination of the structure of these compounds. The application of different onium salts is immense. Ammonium, phosphonium and sulfonium salts are used as phase-transfer catalysts; diazonium salts - for the preparation of dyes, metalochromic and pH-indicators. All the onium salts and especially diazonium and iodonium salts are very useful reagents in organic synthesis.

Tsarevsky, Nicolay V.; Slaveykova, Vera; Manev, Stefan; Lazarov, Dobri

1997-06-01

349

8-fluoropurine compounds  

DOEpatents

An efficient, regiocontrolled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F.sub.2 in He or other inert gas.

Barrio, Jorge R. (Agoura Hills, CA); Satyamurthy, Nagichettiar (Los Angeles, CA); Namavari, Mohammad (Los Angeles, CA); Phelps, Michael E. (Encino, CA)

2001-01-01

350

Compound floating pivot micromechanisms  

DOEpatents

A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

Garcia, Ernest J. (Albuquerque, NM)

2001-04-24

351

PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS  

EPA Science Inventory

Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

352

Tagging Classical Sanskrit Compounds  

Microsoft Academic Search

The paper sets out a prima facie case for the claim that the classification of Sanskrit compounds in P??inian tradition can be retrieved from a very slight\\u000a augmentation of the usual enriched context free rules.

Brendan S. Gillon

2009-01-01

353

Terpenoid emissions from fully grown East Siberian Larix cajanderi trees  

NASA Astrophysics Data System (ADS)

While emissions of many volatile compounds, such as terpenoids, have been studied quite intensively in North American and Scandinavian boreal forests, the vast Siberian boreal forests have remained largely unexplored by experimental emission studies. In this study the shoot scale terpenoid emission rates from mature Larix cajanderi trees growing in their natural habitat in Eastern Siberia were measured. Dynamic flow-through enclosure technique was applied for adsorbent sampling (Tenax-TA and Carbopack-B used as adsorbents), and the samples were analysed offline with a gas chromatograph. The emissions were dominated by monoterpenes, which constituted between 61 and 92% of the total emission. About half of the monoterpene emissions comprised of ?3-carene; ?- and ?-pinene had significant emissions as well. Linalool emissions were also substantial, especially in June. Sesquiterpenes accounted for less than 3% and isoprene less than 1% of the total emissions. Based on the measured emission rates, the relative atmospheric concentration of each compound was estimated. Monoterpenes were the species with the highest relative concentration, while linalool and sesquiterpenes had a notably smaller contribution to the estimated atmospheric concentration than to the emission rates. Temperature dependent pool algorithm with a constant ? (0.09 °C-1 for monoterpenes and 0.143 °C-1 for sesquiterpenes) was used to normalize the measured emission data. For monoterpenes the emission potential varied between 0.5-18.5 ?g gdw-1 h-1 and for sesquiterpenes between 0.02 and 0.4 ?g gdw-1 h-1.

Kajos, M. K.; Hakola, H.; Holst, T.; Nieminen, T.; Tarvainen, V.; Maximov, T.; Petäjä, T.; Arneth, A.; Rinne, J.

2013-03-01

354

Surface chemistry of organophosphorus compounds  

SciTech Connect

Heterogeneous reactions currently offer one of the most favorable technological routes to the removal of air pollutants from the atmosphere. Indeed, the application of heterogeneous catalytic methods to automotive emission control represents the most-widespread exposure of the public to the benefits of catalytic technology, costing the public about $3 billion annually for all automobiles and light-duty trucks manufactured in the United States. A more-specialized area of environmental protection involves the purification of breathing air in hazardous environments such as those exposed to chemical warfare agents. Degradation of pesticides and herbicides is a related area of importance. There is a pressing need to develop reliable methods to chemically transform into harmless substances, catalytically or stoichio-metrically, a variety of types of environmental threats. This paper reviews the known decomposition chemistry of organophosphorus compounds interacting with metal and metal oxide surfaces. Three kinds of processes - oxidation, dealkylation, and hydrolysis - are known to be important, but the fundamental knowledge base in this technologically and environmentally important area is presently inadequate. Some significant research directions are identified for surface chemical science, surface reaction chemistry, solid-state synthesis, and organometallic cluster chemistry.

Ekerdt, J.G.; Klabunde, K.J.; Shapley, J.R.; White, J.M.; Yates, J.T.

1988-01-01

355

Metabolism of nitroaromatic compounds.  

PubMed

There appear to be two major pathways for the metabolism of nitrobenzene and substituted nitrobenzenes. The first of these is reduction of the nitro group to yield aniline or substituted anilines. For nitrobenzene and perhaps for pentachloronitrobenzene, reduction of the nitro group to the amine is accomplished by bacteria of the gastrointestinal tract. Addition of a second nitro group results in easier reduction of one of the nitro groups on dinitrobenzenes, since they can be reduced under aerobic conditions by hepatic and erythrocyte enzymes. Bacterial reduction of the dinitrobenzenes is probably not quantitatively important in vivo. The second pathway is replacement of a nitro group by glutathione. The relative importance of this pathway compared to nitro group reduction depends upon the compound. It has not been demonstrated to occur for nitrobenzene. It is the major route of metabolism for 1,2-dinitrobenzene but is not an important route for 1,3- or 1,4-dinitrobenzene in hepatocytes. Tetrachloronitrobenzene isomers in which the nitro group is flanked by chlorines and pentachloronitrobenzene undergo nitro group replacement, but 2,3,4,5-tetrachloronitrobenzene does not. The most important pathway for the metabolism of mononitrotoluenes is methyl group oxidation. All quantitatively important metabolites are apparently formed from the nitrobenzyl alcohols. The mono- and dinitrotoluenes are not significantly reduced to isolatable metabolites by mammalian enzymes in vivo; intestinal microflora reduce these compounds after biliary excretion of the nitrobenzyl glucuronides. The little available evidence suggests that this is not the case for trinitrotoluenes. Urinary metabolites retain the methyl group and bear one or two amino groups. This suggests either that mammalian enzymes are capable of reducing the nitro groups of trinitrotoluenes in vivo or that intestinal microflora gain access to unmodified trinitrotoluene. The nitropolycyclic aromatic hydrocarbons are apparently metabolized by both nitro reduction and ring oxidation. There is good evidence, at least for 1-nitropyrene and 6-nitrobenzo[a]pyrene, that nitro reduction occurs in intestinal microflora. the complexities of foreign compound metabolism are well illustrated by the biotransformation of the nitroaromatic compounds. Positional isomers are preferentially metabolized by markedly different pathways. Substitution to different degrees or with different functional groups greatly affects the types of metabolites formed. Yet these compounds also offer opportunities for understanding the mechanisms of foreign compound metabolism.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3311683

Rickert, D E

1987-01-01

356

Diesel fuel containing rare earth metal and oxygenated compounds  

Microsoft Academic Search

Addition of an oxygenated compound and a diesel fuel soluble form of a rare earth metal has been found to reduce particulate emissions from a diesel fueled engine. Preferred soluble rare earth metal additives include cerium carbonyls such as cerium salts of alkylcarboxylic acids and cyclic carboxylic acids.

A. M. Mourao; C. H. Faist

1985-01-01

357

The changing oxidizing environment in London - trends in ozone precursors and their contribution to ozone production  

NASA Astrophysics Data System (ADS)

Ground-level ozone is recognized to be a threat to human health (WHO, 2003), have a deleterious impact on vegetation (Fowler et al., 2009), is also an important greenhouse gas (IPCC, 2007) and key to the oxidative ability of the atmosphere (Monks et al., 2009). Owing to its harmful effect on health, much policy and mitigation effort has been put into reducing its precursors - the nitrogen oxides (NOx) and non-methane volatile organic compounds (NMVOCs). The non-linear chemistry of tropospheric ozone formation, dependent mainly on NOx and NMVOC concentrations in the atmosphere, makes controlling tropospheric ozone complex. Furthermore, the concentration of ozone at any given point is a complex superimposition of in-situ produced or destroyed ozone and transported ozone on the regional and hemispheric-scale. In order to effectively address ozone, a more detailed understanding of its origins is needed. Here we show that roughly half (5 ?g m-3) of the observed increase in urban (London) ozone (10 ?g m-3) in the UK from 1998 to 2008 is owing to factors of local origin, in particular, the change in NO : NO2 ratio, NMVOC : NOx balance, NMVOC speciation, and emission reductions (including NOx titration). In areas with previously higher large concentrations of nitrogen oxides, ozone that was previously suppressed by high concentrations of NO has now been "unmasked", as in London and other urban areas of the UK. The remaining half (approximately 5 ?g m-3) of the observed ozone increase is attributed to non-local factors such as long-term transport of ozone, changes in background ozone, and meteorological variability. These results show that a two-pronged approach, local action and regional-to-hemispheric cooperation, is needed to reduce ozone and thereby population exposure, which is especially important for urban ozone.

von Schneidemesser, E.; Vieno, M.; Monks, P. S.

2014-01-01

358

Identification and quantification of volatile organic compounds from a dairy  

NASA Astrophysics Data System (ADS)

Volatile organic compounds (VOCs) that contribute to odor and air quality problems have been identified from the Washington State University Knott Dairy Farm using gas chromatography-mass spectroscopy (GC-MS). Eighty-two VOCs were identified at a lactating cow open stall and 73 were detected from a slurry wastewater lagoon. These compounds included alcohols, aldehydes, ketones, esters, ethers, aromatic hydrocarbons, halogenated hydrocarbons, terpenes, other hydrocarbons, amines, other nitrogen containing compounds, and sulfur-containing compounds. The concentration of VOCs directly associated with cattle waste increased with ambient air temperature, with the highest concentrations present during the summer months. Concentrations of most detected compounds were below published odor detection thresholds. Emission rates of ethanol (1026±513 ?g cow -1 s -1) and dimethyl sulfide (DMS) (13.8±10.3 ?g cow -1 s -1) were measured from the lactating stall area using an atmospheric tracer method and concentrations were plotted using data over a 2-year period. Emission rates of acetone (3.03±0.85 ng cow -1 s -1), 2-butanone (145±35 ng cow -1 s -1), methyl isobutyl ketone (3.46±1.11 ng cow -1 s -1), 2-methyl-3-pentanone (25.1±8.0 ng cow -1 s -1), DMS (2.19±0.92 ng cow -1 s -1), and dimethyl disulfide (DMDS) (16.1±3.9 ng cow -1 s -1) were measured from the slurry waste lagoon using a laboratory emission chamber.

Filipy, Jenny; Rumburg, Brian; Mount, George; Westberg, Hal; Lamb, Brian

359

THE EFFECT OF CONTRALATERAL PURE TONES ON THE COMPOUND ACTION POTENTIAL IN HUMANS  

E-print Network

The compound action potential (CAP) has been suggested in the literature as an alternative to otoacoustic emissions (OAE) for evaluating the efferent auditory system, and is thought to overcome some of the drawbacks ...

Najem, Fadi Jamil

2013-08-31

360

METHODS FOR ANALYZING INORGANIC COMPOUNDS IN PARTICLES EMITTED FROM STATIONARY SOURCES  

EPA Science Inventory

The research described was initiated with the objective of developing methods to identify and measure inorganic compounds in particulate emissions which emanate from sources using or processing fossil fuels. An extensive literature review was carried out to ascertain prior knowle...

361

Organic compounds in meteorites  

NASA Technical Reports Server (NTRS)

Recent studies of carbonaceous chondrites provide evidence that certain organic compounds are indigenous and the result of an abiotic, chemical synthesis. The results of several investigators have established the presence of amino acids and precursors, mono- and dicarboxylic acids, N-heterocycles, and hydrocarbons as well as other compounds. For example, studies of the Murchison and Murray meteorites have revealed the presence of at least 40 amino acids with nearly equal abundances of D and L isomers. The population consists of both protein and nonprotein amino acids including a wide variety of linear, cyclic, and polyfunctional types. Results show a trend of decreasing concentration with increasing carbon number, with the most abundant being glycine (41 n Moles/g). These and other results to be reviewed provide persuasive support for the theory of chemical evolution and provide the only natural evidence for the protobiological subset of molecules from which life on earth may have arisen.

Lawless, J. G.

1980-01-01

362

Oral compound nevus.  

PubMed

The melanocytic nevus is a benign and focal proliferation of nevus cells that can be congenital or acquired. Intraoral lesions are uncommon, and the etiology and pathogenesis are poorly understood. The occurrence rate of oral compound nevus is about 5.9% to 16.5% of all oral melanocytic nevi. A 22-year-old male patient presented with a dark brown macule on the buccal mucosa of the maxilla in the region of tooth 26. The lesion was elliptical, 0.7 x 0.5 cm, well circumscribed, asymptomatic, and the evolution time was unknown. An excisional biopsy was performed and microscopic analysis revealed nests of nevus cells in the epithelium and underlying connective tissue that were compatible with melanocytic compound nevus. Owing to the clinical similarity between oral melanocytic nevus and oral melanoma, a histopathological analysis is mandatory for definitive diagnosis. PMID:24612575

Cardoso, Lyzete Berriel; Consalaro, Alberto; da Silva Santos, Paulo Sérgio; da Silva Sampieri, Marcelo Bonifácio; Tinoco-Araújo, José Endrigo

2014-02-01

363

Compound in Cubic Phase  

NASA Astrophysics Data System (ADS)

In this paper, electronic band structure, total density of states, and optical, lattice dynamic and thermo-dynamic properties of BaCeO3 compound in cubic phase were investigated using density functional theory within the generalized gradient approximation. The calculated lattice constant is consistent with the experimental result. In cubic phase, BaCeO3 has a semiconductor character with 2.17 eV band gap.

Aycibin, Murat; Erdinc, Bahattin; Akkus, Harun

2014-11-01

364

Immunomodulating compounds in Basidiomycetes  

PubMed Central

Mushrooms are distinguished as important food containing immunomodulating and anticancer agents. These compounds belong mostly to polysaccharides especially ?-d-glucans. Among them, ?-1,3-glucan with side chain ?-1,6-glucose residues have more important roles in immunomodulating and antitumor activities. In this review, we have introduced polysaccharide mainly from Lentinula edodes and Agaricus blazei Murill with immunomodulating and antitumor activities. In addition, the mechanism of activation of immune response and signal cascade are also reviewed. PMID:23704809

Mizuno, Masashi; Nishitani, Yosuke

2013-01-01

365

Compound semiconductor SPAD arrays  

NASA Astrophysics Data System (ADS)

Single photon avalanche diodes (SPADs) are revolutionizing ultra-sensitive photodetection applications, providing single photon sensitivity, high quantum efficiency and low dark noise at or near room temperature. When aggregated into arrays, these devices have demonstrated the ability to operate as photon number resolving detectors with wide dynamic range, or as single-photon imaging detectors. SPAD array performance has reached a point where replacing vacuum tube based MCP and PMT photodetectors for most applications is inevitable. Compound semiconductor SPAD arrays offer the unique proposition to tailor performance to match application specific wavelength, speed and radiation hardness requirements. We present a theoretical framework describing performance limits to compound semiconductor SPAD arrays and our latest experimental results detailing the performance of GaAs SPAD arrays. These devices achieve nanosecond rise and fall times, excellent photon number resolving capability, and low dark count rates. Single photon number resolving is demonstrated with 4% single photon detection efficiency at room temperature with dark count rates below 7 Mcps/mm2. Compound semiconductor SPAD arrays have the opportunity to provide orders of magnitude improvement in dark count rate and radiation hardness over silicon SPAD arrays, as well as the ability to detect wavelengths where silicon is blind.

Harmon, Eric S.; Naydenkov, Mikhail; Hyland, James T.

2013-06-01

366

Toxic compounds in honey.  

PubMed

There is a wealth of information about the nutritional and medicinal properties of honey. However, honey may contain compounds that may lead to toxicity. A compound not naturally present in honey, named 5-hydroxymethylfurfural (HMF), may be formed during the heating or preservation processes of honey. HMF has gained much interest, as it is commonly detected in honey samples, especially samples that have been stored for a long time. HMF is a compound that may be mutagenic, carcinogenic and cytotoxic. It has also been reported that honey can be contaminated with heavy metals such as lead, arsenic, mercury and cadmium. Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. In addition, Melicope ternata and Coriaria arborea from New Zealand produce toxic honey that can be fatal. There are reports that honey is not safe to be consumed when it is collected from Datura plants (from Mexico and Hungary), belladonna flowers and Hyoscamus niger plants (from Hungary), Serjania lethalis (from Brazil), Gelsemium sempervirens (from the American Southwest), Kalmia latifolia, Tripetalia paniculata and Ledum palustre. Although the symptoms of poisoning due to honey consumption may differ depending on the source of toxins, most common symptoms generally include dizziness, nausea, vomiting, convulsions, headache, palpitations or even death. It has been suggested that honey should not be considered a completely safe food. PMID:24214851

Islam, Md Nazmul; Khalil, Md Ibrahim; Islam, Md Asiful; Gan, Siew Hua

2014-07-01

367

Biodegradable plastic reduces ammonia emission during composting  

Microsoft Academic Search

Ammonia is the greatest nuisance odor compound among the exhaust gases that evolve during the composting process, in which raw materials with high concentrations of nitrogen, such as wastewater sludge, are decomposed. In the present study, a reduction of NH3 emission during composting of wastewater sludge was tried by mixing biodegradable plastic into composting raw material. Biodegradable plastic acts as

K Nakasaki; A Ohtaki; H Takano

2000-01-01

368

SPECIATE - EPA'S DATABASE OF SPECIATED EMISSION PROFILES  

EPA Science Inventory

SPECIATE is the U.S. Environmental Protection Agency's (EPA) repository of total organic compound (TOC) and particulate matter (PM) speciation profiles for emissions from air pollution sources. The data base has recently been updated and an associated report has recently been re...

369

REDUCING STYRENE EMISSIONS FROM SPRAYED FILLED RESINS  

EPA Science Inventory

Styrene emissions are coming under increasing study as the U.S. Environmental Protection Agency (EPA) develops maximum achievable control technology standards. During the manufacture of fiber-reinforced plastics/composites products, styrene, a volatile organic compound and a haz...

370

DETERMINATION OF ORGANIC EMISSIONS FROM NEW CARPETING  

EPA Science Inventory

New carpeting has been the source of a number of indoor air health and odor complaints. nvestigations of a variety of carpet samples have shown that there is a diversity of organic emissions among carpet types; some of the compounds found have been listed in the NIOSH Registry of...

371

Implementing Strategies for Drying and Pressing Wood Without Emissions Controls  

Microsoft Academic Search

Drying and pressing wood for the manufacture of lumber, particleboard, oriented strand board (OSB), veneer and medium density fiberboard (MDF) release volatile organic compounds (VOCs) into the atmosphere. These emissions require control equipment that are capital-intensive and consume significant quantities of natural gas and electricity. The objective of our work was to understand the mechanisms through which volatile organic compounds

Sujit Banerjee; Terrance Conners

2007-01-01

372

Trimethylamine emissions in animal husbandry  

NASA Astrophysics Data System (ADS)

Degradation of plant material by animals is an important transformation pathway in the nitrogen (N) cycle. During the involved processes, volatile reduced alkaline nitrogen compounds, mainly ammonia (NH3) and aliphatic amines such as trimethylamine (TMA), are formed. Today, animal husbandry is estimated to constitute a main source of aliphatic amines in the atmosphere with TMA being the main emitted compound. Here, we show how the interaction between faeces and urine in animal production systems provides the primary source for agricultural TMA emissions. Excreted urine contains large quantities of urea and TMA-N-oxide, which are transformed into NH3 and TMA, respectively, via enzymatic processes provided by microbes present in faeces. TMA emissions from areas polluted with urine-faeces mixtures are on average of the order of 10 to 50 nmol m-2s-1. Released amines promote secondary aerosol particle formation in the agricultural emission plume. The atmospheric lifetime of TMA, which was estimated to be of the order of 30 to 1000 s, is determined by the condensation onto aerosol particles.

Sintermann, J.; Schallhart, S.; Kajos, M.; Jocher, M.; Bracher, A.; Münger, A.; Johnson, D.; Neftel, A.; Ruuskanen, T.

2014-09-01

373

DEVELOPING SEASONAL AMMONIA EMISSION ESTIMATES WITH AN INVERSE MODELING TECHNIQUE  

EPA Science Inventory

Significant uncertainty exists in magnitude and variability of ammonia (NH3) emissions, which are needed for air quality modeling of aerosols and deposition of nitrogen compounds. Approximately 85% of NH3 emissions are estimated to come from agricultural non-point sources. We sus...

374

Emissions of volatile aldehydes from heated cooking oils  

Microsoft Academic Search

Emissions of volatile organic compounds, including aldehydes, formed during heating of cooking oils: coconut, safflower, canola, and extra virgin olive oils were studied at different temperatures: 180, 210, 240, and 240°C after 6h. Fumes were collected in Tedlar® bags and later analysed by GC–MS. The emissions of volatiles were constant with time and increased with the oil temperature. When the

Harinageswara Rao Katragadda; Andrés Fullana; Sukh Sidhu; Ángel A. Carbonell-Barrachina

2010-01-01

375

Ground-level ozone influenced by circadian control of isoprene emissions  

Microsoft Academic Search

The volatile organic compound isoprene is produced by many plant species, and provides protection against biotic and abiotic stresses. Globally, isoprene emissions from plants are estimated to far exceed anthropogenic emissions of volatile organic compounds. Once in the atmosphere, isoprene reacts rapidly with hydroxyl radicals to form peroxy radicals, which can react with nitrogen oxides to form ground-level ozone. Here,

C. N. Hewitt; K. Ashworth; A. Boynard; A. Guenther; B. Langford; A. R. MacKenzie; P. K. Misztal; E. Nemitz; S. M. Owen; M. Possell; T. A. M. Pugh; A. C. Ryan; O. Wild

2011-01-01

376

40 CFR 63.3165 - How do I determine the emission capture system efficiency?  

Code of Federal Regulations, 2010 CFR

...Hazardous Air Pollutants: Surface Coating of Automobiles and Light-Duty Trucks Compliance...Volatile Organic Compound Emission Rate of Automobile and Light-Duty Truck Topcoat Operations...Volatile Organic Compound Emission Rate of Automobile and Light-Duty Truck...

2010-07-01

377

Isoprene emission from tropical tree species.  

PubMed

Foliar emission of isoprene was measured in nine commonly growing tree species of Delhi, India. Dynamic flow enclosure technique was used and gas samples were collected onto Tenax-GC/Carboseive cartridges, which were then attached to the sample injection system in the gas chromatograph (GC). Eluting compounds were analysed using a flame ionisation detector (FID). Out of the nine tree species, isoprene emission was found in six species (Eucalyptus sp., Ficus benghalensis, Ficus religiosa, Mangifera indica, Melia azedarach, and Syzygium jambolanum), whereas, in the remaining three tree species (Alstonia scholaris, Azadirachta indica, and Cassia fistula) no isoprene emission was detected or the levels of emission were negligible or below the detection limit (BDL). Among six tree species, the highest hourly emission (10.2 +/- 6.8 microg g(-1) leaf dry weight, average of five seasons) was observed in Ficus religiosa, while minimum emission was from Melia azedarach (2.2 +/- 4.9 microg g(-1) leaf dry weight, average of five seasons). Isoprene emission (average of six species), over five seasons, was found to vary between 3.9 and 8.5 microg g(-1) leaf dry weight during the rainy season. In addition, significant diurnal variation in isoprene emission was observed in each species. The preliminary estimate made in this study on the annual biogenic VOC emission from India may probably be the first of its kind from this part of the world. PMID:15701397

Padhy, P K; Varshney, C K

2005-05-01

378

Emission of methyl bromide from biomass burning  

SciTech Connect

Bromine is, per atom, far more efficient than chlorine in destroying stratospheric ozone, and methyl bromide is the single largest source of stratospheric bromine. The two main previously known sources of this compound are emissions from the ocean and from the compound's use as an agricultural pesticide. Laboratory biomass combustion experiments showed that methyl bromide was emitted in the smoke from various fuels tested. Methyl bromide was also found in smoke plumes from wildfires in savannas, chaparral, and boreal forest. Global emissions of methyl bromide from biomass burning are estimated to be in the range of 10 to 50 gigagrams per year, which is comparable to the amount produced by ocean emission and pesticide use and represents a major contribution ([approximately]30 percent) to the stratospheric bromine budget.

Manoe, S.; Andreae, M.O. (Max Planck Institute for Chemistry, Mainz (Germany))

1994-03-04

379

Measuring global sulfur dioxide emissions with satellite sensors  

NASA Astrophysics Data System (ADS)

Atmospheric sulfur dioxide affects the weather by enhancing cloud formation, and long-term shifts in emissions can change the climate by increasing the amount of solar radiation scattered back into space. Sulfur dioxide emissions are the basis for acid rain, and the gas itself can cause respiratory problems. Despite the compound's importance to climate, the difficulties associated with accurately measuring sulfur dioxide mean that rates of emissions are generally not well understood.

Schultz, Colin

2013-11-01

380

Junction-based field emission structure for field emission display  

DOEpatents

A junction-based field emission display, wherein the junctions are formed by depositing a semiconducting or dielectric, low work function, negative electron affinity (NEA) silicon-based compound film (SBCF) onto a metal or n-type semiconductor substrate. The SBCF can be doped to become a p-type semiconductor. A small forward bias voltage is applied across the junction so that electron transport is from the substrate into the SBCF region. Upon entering into this NEA region, many electrons are released into the vacuum level above the SBCF surface and accelerated toward a positively biased phosphor screen anode, hence lighting up the phosphor screen for display. To turn off, simply switch off the applied potential across the SBCF/substrate. May be used for field emission flat panel displays.

Dinh, Long N. (Concord, CA); Balooch, Mehdi (Berkeley, CA); McLean, II, William (Oakland, CA); Schildbach, Marcus A. (Livermore, CA)

2002-01-01

381

Complex Compound Chemical Heat Pumps  

E-print Network

Complex-compound solid-vapor fluid pairs can be used in heat of reaction heat pumps for temperature amplifier (TA) as well as heat amplifier (HA) cycle configurations. This report describes the conceptual hardware design for complex compound...

Rockenfeller, U.; Langeliers, J.; Horn, G.

382

Color Classification of Coordination Compounds.  

ERIC Educational Resources Information Center

Proposes that colored compounds be classified by reference to a standard color-order system incorporating a color dictionary. Argues that the colors of new compounds could be incorporated into the characterization process and into computer storage systems. (TW)

Poncini, Laurence; Wimmer, Franz L.

1987-01-01

383

Bilingual reading of compound words.  

PubMed

The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English compound words was more accurate when the translated compounds (the combination of the translation equivalents of the constituents) in Korean (the nontarget language) were real words than when they were nonwords. In Experiment 2, when the frequency of the second constituents of compound words in English (the target language) was manipulated, the effect of lexical status of the translated compounds was greater on the compounds with high-frequency second constituents than on those with low-frequency second constituents in the target language. Together, these results provided evidence for morphological decomposition and cross-language activation in bilingual reading of compound words. PMID:20623255

Ko, In Yeong; Wang, Min; Kim, Say Young

2011-02-01