Sample records for compound nmvoc emissions

  1. Spatial and temporal variation of emission inventories for historical anthropogenic NMVOCs in China

    NASA Astrophysics Data System (ADS)

    Bo, Y.; Cai, H.; Xie, S. D.

    2008-06-01

    Multiyear emission inventories of anthropogenic NMVOCs in China for 1980-2005 were compiled based on time-varying statistical data, literature surveyed and model calculated emission factors, and were gridded at a high spatial resolution of 40 km×40 km using the GIS methodology. Chinese NMVOCs emissions had increased by 4.3 times at an annual average rate of 10.7% from 3.92 Tg in 1980 to 16.5 Tg in 2005. Vehicles, biomass burning, industrial processes, fossil fuel combustion, solvent utilization, and storage and transport generated 5.49 Tg, 3.91 Tg, 2.76 Tg, 1.98 Tg, 1.87 Tg, and 0.55 Tg of NMVOCs, respectively. Motorcycles, biofuel burning, heavy-duty vehicles, synthetic fibre production, biomass open burning, and industrial and commercial consumption were primary emission sources. Besides, from 1980 to 2005, vehicle emission increased notably from 6% to 33%, along with a slight increase for fossil fuel combustion from 9% to 12% and for industrial processes from 11% to 17%. Meanwhile, biomass burning emission decreased from 41% to 23%, along with the decrease of storage and transport and solvent utilization from 9% to 3% and from 28% to 11%, respectively. Varieties of NMVOCs emissions coincided well with China's economic growth. Conversions in economic structure and adjustment of fuel consumption structure in China during the period were the reasons for conspicuous variation of source contributions. The developed eastern and coastal regions produced more emissions than the relatively underdeveloped western and inland regions. Particularly, southeastern, northern, and central China covering 35% of China's territory, generated 59% of the total emissions, while the populous capital cities covering merely 4.5% of China's territory, accounted for 25% of the national emissions. Moreover, rural areas also experienced emission growth during the past two and a half decades, the reason of which was transfer of emission-intensive plants from city to county, inefficient fuel utilization, and biomass burning.

  2. Historical industrial emissions of non-methane volatile organic compounds in China for the period of 1980-2010

    NASA Astrophysics Data System (ADS)

    Qiu, Kaiqiong; Yang, Lixian; Lin, Junmin; Wang, Peitao; Yang, Yi; Ye, Daiqi; Wang, Liming

    2014-04-01

    This paper presents a new classification of industrial sector on basis of a source-tracing method for the historical industrial emissions of non-methane volatile organic compounds (NMVOCs). The industrial sources were divided into four major source categories: production of NMVOCs, storage and transport, industrial processes using NMVOCs as raw materials, and processes using NMVOCs-containing products. Multiyear emission inventories of NMVOCs from industrial sources were established for the period of 1980-2010 in China, covering 98 contributing industrial sources. The inventories were developed by the emission factor method, and further gridded at a spatial resolution of 50 km × 50 km based on GIS methodology, using population data as spatial surrogate. The result showed that China's industrial NMVOCs emissions had increased by 11.6 times at an average annual rate of 8.5% from 1.15 Tg in 1980 to 13.35 Tg in 2010. The four major source categories generated 19.6% (2.63 Tg, production of NMVOCs), 9.6% (1.295 Tg, storage and transport), 13.2% (1.769 Tg, industrial processes using NMVOCs as raw materials), and 57.4% (7.662 Tg, processes using NMVOCs-containing products) of the total emissions from China in 2010. Moreover, the top four industrial emissions sources were oil refinery, architectural decoration, machinery equipment and printing, accounted for 48.3% all together. With respect to the spatial distribution, the emissions mostly occurred in the eastern, northern and southern parts of China, all being much higher than that in the western part. The top four emission provinces were Shandong, Jiangsu, Guangdong, and Zhejiang, accounting for 38.3% of the national emissions. As for the past 30 years, the national industrial NMVOCs emissions increased year-by-year, being in pace with the accelerated industrialization process and the sharp economic growth, especially the rapid expansion of the high-emission industries. Particularly, the oil refinery, product oil and solvent distribution, architectural decoration, and mechanical equipment manufacture became the four largest contributors, accounting for 15.9-34.3%, 6.5-10.2%, 7-8%, and 6-7% of national industrial NMVOCs.

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

    Microsoft Academic Search

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

    2000-01-01

    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

  4. Sensitivity of Modeled European Ozone Concentrations to NMVOC Speciation

    NASA Astrophysics Data System (ADS)

    Mar, K. A.; von Schneidemesser, E.; Coates, J.; Denier Van Der Gon, H.; Visschedijk, A.; Butler, T. M.

    2014-12-01

    In European emission inventories, the solvent sector is one of the top contributors to total anthropogenic NMVOC emissions, along with the transport sector. However, the speciation profile for solvent NMVOCs (i.e., which individual species make up these NMVOC emissions) is very uncertain, with different data sources showing significant differences. Because of differences in reactivity between individual VOCs, the differences in solvent NMVOC speciation have the potential to lead to significant differences in predicted ozone concentrations. Initial box model studies have shown that these speciation differences can lead to differences in ozone concentrations of up to 40 ?g/m3 (20 ppb) under idealized conditions. Here we use the regional chemistry and circulation model WRF-CHEM, implemented for the European domain, to examine the sensitivity of predicted ozone to different NMVOC speciations applied to European solvent-sector emissions. These results will be used to evaluate if an investment in developing updated, detailed NMVOC speciations by source sector is necessary for an improved representation of ozone pollution in Europe.

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

    NASA Astrophysics Data System (ADS)

    Cai, H.; Xie, S. D.

    2009-05-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Cai, H.; Xie, S. D.

    2009-09-01

    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.

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

    PubMed

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

    2014-07-01

    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

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

    Microsoft Academic Search

    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

    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

  9. Emission and speciation of non-methane volatile organic compounds from anthropogenic sources in China

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Wang, Shuxiao; Chatani, Satoru; Klimont, Zbigniew; Cofala, Janusz; Hao, Jiming

    An emission inventory of non-methane volatile organic compounds (NMVOCs) from anthropogenic sources in China was compiled for the year 2005. The NMVOC emissions were 20.1 Tg, of which industrial and domestic solvent use, road transportation, and bio-fuel combustion contributed 28.6%, 23.4%, and 18.0%, respectively. Emissions were speciated into 40 species according to their atmospheric photochemical reactivity, toxicity, and model applicability. Of the total emissions, alkanes account for 29.8%, followed by aromatics (21.9%), alkenes and alkynes (21.0%), and carbonyls (17.8%). Emissions at the provincial level were spatially allocated onto grids with a resolution of 36 km×36 km, according to population distribution. Furthermore, the provincial and sectoral emissions of nine toxic species, including n-hexane, 1,3-butadiene, styrene, benzene, toluene, xylene, methanol, formaldehyde, and acraldehyde, are also analyzed. Finally, the national total emissions were considered with an uncertainty of [-44%,+109%] in 95% confidence interval, by using the Monte Carlo method.

  10. Estimating the biogenic emissions of non-methane volatile organic compounds from the North Western Mediterranean vegetation of Catalonia, Spain.

    PubMed

    Parra, R; Gassó, S; Baldasano, J M

    2004-08-15

    An estimation of the magnitude of non-methane volatile organic compounds (NMVOCs) emitted by vegetation in Catalonia (NE of the Iberian Peninsula, Spain), in addition to their superficial and temporal distribution, is presented for policy and scientific (photochemical modelling) purposes. It was developed for the year 2000, for different time resolutions (hourly, daily, monthly and annual) and using a high-resolution land-use map (1-km2 squared cells). Several meteorological surface stations provided air temperature and solar radiation data. An adjusted mathematical emission model taking account of Catalonia's conditions was built into a geographic information system (GIS) software. This estimation uses the latest information, mainly relating to: (1) emission factors; (2) better knowledge of the composition of Catalonia's forest cover; and (3) better knowledge of the particular emission behaviour of some Mediterranean vegetal species. Results depict an annual cycle with increasing values in the March-April period with the highest emissions in July-August, followed by a decrease in October-November. Annual biogenic NMVOCs emissions reach 46.9 kt, with monoterpenes the most abundant species (24.7 kt), followed by other biogenic volatile organic compounds (e.g. alcohols, aldehydes and acetone) (16.3 kt), and isoprene (5.9 kt). These compounds signify 52%, 35% and 13%, respectively, of total emission estimates. Peak hourly total emission for a winter day could be less than 10% of the corresponding value for a summer day. PMID:15262170

  11. Laboratory measurements of emission factors of nonmethane volatile organic compounds from burning of Chinese crop residues

    NASA Astrophysics Data System (ADS)

    Inomata, Satoshi; Tanimoto, Hiroshi; Pan, Xiaole; Taketani, Fumikazu; Komazaki, Yuichi; Miyakawa, Takuma; Kanaya, Yugo; Wang, Zifa

    2015-05-01

    The emission factors (EFs) of nonmethane volatile organic compounds (NMVOCs) emitted during the burning of Chinese crop residue were investigated as a function of modified combustion efficiency in laboratory experiments. NMVOCs, including acetonitrile, aldehydes/ketones, furan, and aromatic hydrocarbons, were monitored by proton-transfer-reaction mass spectrometry. Rape plant was burned in dry conditions and wheat straw was burned in both wet and dry conditions to simulate the possible burning of damp crop residue in regions of high temperature and humidity. We compared the present data to field data reported by Kudo et al. (2014). Good agreement between field and laboratory data was obtained for aromatics under relatively more smoldering combustion of dry samples, but laboratory data were slightly overestimated compared to field data for oxygenated VOC (OVOC). When EFs from the burning of wet samples were investigated, the consistency between the field and laboratory data for OVOCs was stronger than for dry samples. This may be caused by residual moisture in crop residue that has been stockpiled in humid regions. Comparison of the wet laboratory data with field data suggests that Kudo et al. (2014) observed the biomass burning plumes under relatively more smoldering conditions in which approximately a few tens of percentages of burned fuel materials were wet.

  12. Inventorying emissions from nature in Europe

    Microsoft Academic Search

    David Simpson; Wilfried Winiwarter; Gunnar Börjesson; Steve Cinderby; Antonio Ferreiro; Alex Guenther; C. Nicholas Hewitt; Robert Janson; M. Aslam K. Khalil; Susan Owen; Tom E. Pierce; Hans Puxbaum; Martha Shearer; Ute Skiba; Rainer Steinbrecher; Leonor Tarrasón; Mats G. Öquist

    1999-01-01

    As part of the work of the Economic Commission for Europe of the United Nations Task Force on Emission Inventories, a new set of guidelines has been developed for assessing the emissions of sulphur, nitrogen oxides, NH3, CH4, and nonmethane volatile organic compounds (NMVOC) from biogenic and other natural sources in Europe. This paper gives the background to these guidelines,

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

    SciTech Connect

    Benkovitz, C.M.

    1997-09-01

    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.

  14. Complex fragment emission from hot compound nuclei

    SciTech Connect

    Moretto, L.G.

    1986-03-01

    The experimental evidence for compound nucleus emission of complex fragments at low energies is used to interpret the emission of the same fragments at higher energies. The resulting experimental picture is that of highly excited compound nuclei formed in incomplete fusion processes which decay statistically. In particular, complex fragments appear to be produced mostly through compound nucleus decay. In the appendix a geometric-kinematic theory for incomplete fusion and the associated momentum transfer is outlined. 10 refs., 19 figs.

  15. PTR-MS measurements of non-methane volatile organic compounds during an intensive field campaign at the summit of Mount Tai, China, in June 2006

    NASA Astrophysics Data System (ADS)

    Inomata, Satoshi; Tanimoto, Hiroshi; Kato, Shungo; Suthawaree, Jeeranut; Kanaya, Yugo; Pochanart, Pakpong; Liu, Yu; Wang, Zifa

    2010-05-01

    Owing to recent industrialization, Central East China has become a significant source of air pollutants. To examine the processes controlling the chemistry and transport of tropospheric ozone, we continuously measured non-methane volatile organic compounds (NMVOCs) as part of an intensive field campaign at Mount Tai, China, in June 2006 (MTX2006), using proton transfer reaction mass spectrometry (PTR-MS). Temporal variations of NMVOCs were recorded in mass-scan mode from m/z 17 to m/z 300 during 12-30 June 2006. More than thirty kinds of NMVOCs were detected up to m/z 160, including alkenes, aromatics, alcohols, aldehydes, and ketones. Oxygenated VOCs were the predominant NMVOCs. During the night of 12 June, we observed an episode of high NMVOCs concentrations attributed to the burning of agricultural biomass. The ?NMVOCs/?CO ratios derived by PTR-MS measurements for this episode are compared to emission ratios from various types of biomass burning as reviewed by Andreae and Merlet (2001) and to ratios recently measured by PTR-MS in tropical forests (Karl et al., 2007) and at urban sites (Warneke et al., 2007).

  16. PTR-MS measurements of non-methane volatile organic compounds during an intensive field campaign at the summit of Mount Tai, China, in June 2006

    NASA Astrophysics Data System (ADS)

    Inomata, S.; Tanimoto, H.; Kato, S.; Suthawaree, J.; Kanaya, Y.; Pochanart, P.; Liu, Y.; Wang, Z.

    2009-12-01

    Owing to recent industrialization, Central East China has become a significant source of air pollutants. To examine the processes controlling the chemistry and transport of tropospheric ozone, we continuously measured non-methane volatile organic compounds (NMVOCs) as part of an intensive field campaign at Mount Tai, China, in June 2006 (MTX2006), using proton transfer reaction mass spectrometry (PTR-MS). Temporal variations of NMVOCs were recorded in mass-scan mode from m/z 17 to m/z 300 during 12-30 June 2006. More than thirty kinds of NMVOCs were detected up to m/z 160, including alkenes, aromatics, alcohols, aldehydes, and ketones. Oxygenated VOCs were the predominant NMVOCs. During the night of 12 June, we observed an episode of high NMVOCs concentrations attributed to the burning of agricultural biomass. The ?NMVOCs/?CO ratios derived by PTR-MS measurements for this episode are compared to emission ratios from various types of biomass burning as reviewed by Andreae and Merlet (2001) and to ratios recently measured by PTR-MS in tropical forests (Karl et al., 2007) and at urban sites (Warneke et al., 2007).

  17. PTR-MS measurements of non-methane volatile organic compounds during an intensive field campaign at the summit of Mount Tai, China, in June 2006

    NASA Astrophysics Data System (ADS)

    Inomata, S.; Tanimoto, H.; Kato, S.; Suthawaree, J.; Kanaya, Y.; Pochanart, P.; Liu, Y.; Wang, Z.

    2010-08-01

    Owing to recent industrialization, Central East China has become a significant source of air pollutants. To examine the processes controlling the chemistry and transport of tropospheric ozone, we performed on-line measurements of non-methane volatile organic compounds (NMVOCs) as part of an intensive field campaign at Mount Tai, China, in June 2006 (MTX2006), using proton transfer reaction mass spectrometry (PTR-MS). Temporal variations of NMVOCs were recorded in mass-scan mode from m/z17 to m/z 300 during 12-30 June 2006. More than thirty kinds of NMVOCs were detected up to m/z 160, including alkenes, aromatics, alcohols, aldehydes, and ketones. In combination with non-methane hydrocarbon data obtained by a gas chromatography with flame ionization detection, it was found that oxygenated VOCs were the predominant NMVOCs. Diurnal variations depending mainly on local photochemistry were observed during 24-28 June. During the night of 12 June, we observed an episode of high NMVOCs concentrations attributed to the burning of agricultural biomass. The ?NMVOCs/?CO ratios derived by PTR-MS measurements for this episode (with biomass burning (BB) plume) and during 16-23 June (without BB plume) are compared to emission ratios from various types of biomass burning as reviewed by Andreae and Merlet (2001) and to ratios recently measured by PTR-MS in tropical forests (Karl et al., 2007) and at urban sites (Warneke et al., 2007).

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

    SciTech Connect

    BENKOVITZ,C.M.

    1997-09-01

    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.

  19. Volatile organic compound emissions from dairy facilities in central California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emissions of volatile organic compounds (VOCs) from dairy facilities are thought to be an important contributor to high ozone levels in central California, but emissions inventories from these sources contain significant uncertainties. In this work, VOC emissions were measured at two central Califor...

  20. POTENTIAL EMISSIONS OF HAZARDOUS ORGANIC COMPOUNDS FROM SEWAGE SLUDGE INCINERATION

    EPA Science Inventory

    Laboratory thermal decomposition studies were undertaken to evaluate potential organic emissions from sewage sludge incinerators. Precisely controlled thermal decomposition experiments were conducted on sludge spiked with mixtures of hazardous organic compounds, on the mixtures o...

  1. Biological aspects of constructing volatile organic compound emission inventories

    Microsoft Academic Search

    Ray Fall; Mt Lerdau; Td Sharkey

    1995-01-01

    The: emission of volatile organic compounds (VOCs) from vegetation is subject to numerous biological controls. Past inventories have relied heavily on empirical models which are limited in their ability to simulate the response of organisms to short- and long-term changes in their growth environment. In this review we consider the principal biochemical, physiological and ecological controls over VOC emission with

  2. MICROBIAL VOLATILE ORGANIC COMPOUND EMISSION RATES AND EXPOSURE MODEL

    EPA Science Inventory

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

  3. Inventorying emissions from nature in Europe

    NASA Astrophysics Data System (ADS)

    Simpson, David; Winiwarter, Wilfried; BöRjesson, Gunnar; Cinderby, Steve; Ferreiro, Antonio; Guenther, Alex; Hewitt, C. Nicholas; Janson, Robert; Khalil, M. Aslam K.; Owen, Susan; Pierce, Tom E.; Puxbaum, Hans; Shearer, Martha; Skiba, Ute; Steinbrecher, Rainer; Tarrasón, Leonor; Äquist, Mats G.

    1999-04-01

    As part of the work of the Economic Commission for Europe of the United Nations Task Force on Emission Inventories, a new set of guidelines has been developed for assessing the emissions of sulphur, nitrogen oxides, NH3, CH4, and nonmethane volatile organic compounds (NMVOC) from biogenic and other natural sources in Europe. This paper gives the background to these guidelines, describes the sources, and gives our recommended methodologies for estimating emissions. We have assembled land use and other statistics from European or national compilations and present emission estimates for the various natural/biogenic source categories based on these. Total emissions from nature derived here amount to ˜1.1 Tg S yr-1, 6-8 Tg CH4 yr-1, 70 Gg NH3 (as N) yr-1, and 13 Tg NMVOC yr-1. Estimates of biogenic NOx emissions cover a wide range, from 140 to 1500 Gg NOx (as N) yr-1. In terms of relative contribution to total European emissions for different pollutants, then NMVOC from forests and vegetation are clearly the most important emissions source. Biogenic NOx emissions (although heavily influenced by nitrogen inputs from anthropogenic activities) are very important if the higher estimates are reliable. CH4 from wetlands and sulphur from volcanoes are also significant emissions in the European budgets. On a global scale, European biogenic emissions are not significant, a consequence of the climate and size (7% of global land area) of Europe and of the destruction of natural ecosystems since prehistoric times. However, for assessing local budgets and for photochemical oxidant modeling, natural/biogenic emissions can play an important role. The most important contributor in this regard is undoubtedly forest VOC emissions, although this paper also indicates that NMVOC emissions from nonforested areas also need to be further evaluated. This paper was originally conceived as a contribution to the collection of papers arising as a result of the Workshop on Biogenic Hydrocarbons in the Atmospheric Boundary Layer, August 24-27, 1997. (Several papers arising from this workshop have been published in Journal of Geophysical Research, 103(D19) 1998.)

  4. Microbial Volatile Organic Compound Emission Rates and Exposure Model

    Microsoft Academic Search

    M. Y. Menetrez; K. K. Foarde

    2002-01-01

    This paper presents the results from a study that examined microbial volatile organic compound (MVOC) emissions from six fungi and one bacterial species (Streptomyces spp.) commonly found in indoor environments. Data are presented on peak emission rates from inoculated agar plates loaded with surface growth, ranging from 33.5 ?g·m–2 per 24 h (Cladosporium sphaerospermum) to 515 ?g·m–2 per 24 h

  5. Emission of volatile organic compounds from coal combustion

    Microsoft Academic Search

    H. K Chagger; J. M Jones; M Pourkashanian; A Williams; A Owen; G Fynes

    1999-01-01

    The combustion of coal leads to the formation of small but significant amounts of volatile organic compounds (VOCs), toxic organic micropollutants as polynuclear aromatic hydrocarbons (PAHs), as well as CH4. The measurements of such trace emissions is difficult and expensive, consequently it is useful to examine these from a kinetic modelling and thermodynamic point of view in order to make

  6. A global model of natural volatile organic compound emissions

    Microsoft Academic Search

    Alex Guenther; C. Nicholas Hewitt; David Erickson; Ray Fall; Chris Geron; Tom Graedel; Peter Harley; Lee Klinger; Manuel Lerdau; W. A. McKay; Tom Pierce; Bob Scholes; Rainer Steinbrecher; Raja Tallamraju; John Taylor; Pat Zimmerman

    1995-01-01

    Numerical assessments of global air quality and potential changes in atmospheric chemical constituents require estimates of the surface fluxes of a variety of trace gas species. We have developed a global model to estimate emissions of volatile organic compounds from natural sources (NVOC). Methane is not considered here and has been reviewed in detail elsewhere. The model has a highly

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

    Microsoft Academic Search

    Jonathan W. Leff; Noah Fierer

    2008-01-01

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

  8. Microscopic description of neutron emission rates in compound nuclei

    NASA Astrophysics Data System (ADS)

    Zhu, Yi; Pei, J. C.

    2014-11-01

    Background: 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 a microscopic description of thermal neutron emissions is desirable that can aid in understanding such properties as the survival probabilities of superheavy compound nuclei and neutron emissivity in reactors. Purpose: To describe neutron emission rates in deformed compound nuclei, the external thermal neutron gases are self-consistently obtained based on the finite-temperature Hartree-Fock-Bogoliubov (FT-HFB) approach. Methods: The Skyrme FT-HFB equation is solved by the HFB-AX solver in deformed coordinate spaces. Based on the FT-HFB approach, the thermal properties and external neutron gases are properly described with the self-consistent gas substraction procedure. Then neutron emission rates can be obtained with the densities of external neutron gases. The results are compared with the statistical model to explore the connections between the FT-HFB approach and the statistical model. Results: The thermal statistical properties of 238U and 258U are studied in detail in terms of excitation energies. The thermal neutron emission rates in U,258238 and superheavy compound nuclei Cn278112 and Fl292114 are calculated, which agree well with the statistical model by adopting variables from FT-HFB. Conclusions: 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.

  9. Emissions of biogenic volatile organic compounds & their photochemical transformation

    NASA Astrophysics Data System (ADS)

    Yu, Zhujun; Hohaus, Thorsten; Tillmann, Ralf; Andres, Stefanie; Kuhn, Uwe; Rohrer, Franz; Wahner, Andreas; Kiendler-Scharr, Astrid

    2015-04-01

    Natural and anthropogenic activities emit volatile organic compounds (VOC) into the atmosphere. While it is known that land vegetation accounts for 90% of the global VOC emissions, only a few molecules' emission factors are understood. Through VOCs atmospheric oxidation intermediate products are formed. The detailed chemical mechanisms involved are insufficiently known to date and need to be understood for air quality management and climate change predictions. In an experiment using a PTR-ToF-MS with the new-built plant chamber SAPHIR-PLUS in Forschungszentrum Juelich, biogenic emissions of volatile organic compounds (BVOC) from Quercus ilex trees were measured. The BVOC emissions were dominated by monoterpenes, minor emissions of isoprene and methanol were also observed with the overall emission pattern typical for Quercus ilex trees in the growing season. Monoterpenes and isoprene emissions showed to be triggered by light. Additionally, their emissions showed clear exponential temperature dependence under constant light condition as reported in literature. As a tracer for leaf growth, methanol emission showed an abrupt increase at the beginning of light exposure. This is explained as instantaneous release of methanol produced during the night once stomata of leaves open upon light exposure. Emission of methanol showed a near linear increase with temperature in the range of 10 to 35 °C. BVOC were transferred from the plant chamber PLUS to the atmospheric simulation chamber SAPHIR, where their oxidation products from O3 oxidation were measured with PTR-ToF-MS. Gas phase oxidation products such as acetone and acetaldehyde were detected. A quantitative analysis of the data will be presented, including comparison of observations to the Master Chemical Mechanism model.

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

    SciTech Connect

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

    1997-09-01

    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.

  11. 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...

  12. Biogenic volatile organic compound emissions from vegetation fires

    PubMed Central

    CICCIOLI, PAOLO; CENTRITTO, MAURO; LORETO, FRANCESCO

    2014-01-01

    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

  13. Effect of natural compounds on reducing formaldehyde emission from plywood

    NASA Astrophysics Data System (ADS)

    Uchiyama, Shigehisa; Matsushima, Erica; Kitao, Nahoko; Tokunaga, Hiroshi; Ando, Masanori; Otsubo, Yasufumi

    The effects of natural compounds on reducing formaldehyde emission from plywood were investigated. Urea, catechin and vanillin were examined as the natural formaldehyde reducers. The microemission cell, with an internal volume of 35 ml, the maximum exposed test surface area of 177 cm 2 and an air purge flow rate of 50 ml min -1, was used to measure specific emission rate (SER). In the case of no reducer treatment, formaldehyde emission from plywood was fast and SERs were 4.4 mg m -2 h -1 at 30 °C and 15 mg m -2 h -1 at 60 °C. When this plywood was treated with the natural compounds, the SERs of formaldehyde were decreased at all temperatures. In the case of urea treatment, the SERs of formaldehyde decreased to 0.30 mg m -2 h -1 at 30 °C and 0.65 mg m -2 h -1 at 60 °C. When the urea treatment was applied to the inside of kitchen cabinet (made from plywood; 270 cm wide, 60 cm deep, 250 cm high), the concentration of formaldehyde was reduced substantially from 1600 to 130 ?g m -3. The reducing effect of formaldehyde continued during the observation period (6 months), with a mean concentration of 100 ?g m -3. Reducers in the plywood would react with released formaldehyde. Application of natural compounds such as urea, catechin and vanillin could provide a simple and effective approach for suppressing formaldehyde emission from plywood.

  14. Microscopic description of neutron emission rates in compound nuclei

    E-print Network

    Yi Zhu; Junchen Pei

    2014-11-02

    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.

  15. Characterizing reduced sulfur compounds emissions from a swine concentrated animal feeding operation

    E-print Network

    Aneja, Viney P.

    Characterizing reduced sulfur compounds emissions from a swine concentrated animal feeding emissions from swine CAFOs. This article provides a comprehensive analysis of RSCs emissions from a swine sulfide CAFO emissions Swine a b s t r a c t Reduced sulfur compounds (RSCs) emissions from concentrated

  16. Light emission from compound eye with conformal fluorescent coating

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    Compound eyes of insects are attractive biological systems for engineered biomimicry as artificial sources of light, given their characteristic wide angular field of view. A blowfly eye was coated with a thin conformal fluorescent film, with the aim of achieving wide field-of-view emission. Experimental results showed that the coated eye emitted visible light and that the intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

  17. Emissions of carbonyl compounds from various cookstoves in China

    SciTech Connect

    Zhang, J. (UMDNJ--Robert Wood Johnson Medical School and Rutgers Univ., Piscataway (United States). Environmental and Occupational Health Sciences Inst. East-West Center, Honolulu, HI (United States)); Smith, K.R. (East-West Center, Honolulu, HI (United States) Univ. of California, Berkeley, CA (United States). Center for Occupational and Environmental Health)

    1999-07-15

    This paper presents a new database of carbonyl emission factors for commonly used cookstoves in China. The emission factors, reported both on a fuel-mass basis (mg/kg) and on a defined cooking-task basis (mg/task), were determined using a carbon balance approach for 22 types of fuel/stove combinations. These include various stoves using different species of crop residues and wood, kerosene, and several types of coals and gases. The results show that all the tested cookstoves produced formaldehyde and acetaldehyde and that the vast majority of the biomass stoves produced additional carbonyl compounds such as acetone, acrolein, propionaldehyde, crotonaldehyde, 2-butanone, isobutyraldehyde, butyraldehyde, isovaleraldehyde, valeraldehyde, hexaldehyde, benzaldehyde, o-tolualdehyde, m,p-tolualdehyde, and 2,4-dimethylbenzaldehyde. Carbonyls other than formaldehyde and acetaldehyde, however, were rarely generated by burning coal, coal gas, and natural gas. Kerosene and LPG stoves generated more carbonyl compounds than coal, coal gas, and natural gas stoves, but less than biomass stoves. Indoor levels of carbonyl compounds for typical village houses during cooking hours, estimated using a mass balance model and the measured emission factors, can be high enough to cause acute health effects documented for formaldehyde exposure, depending upon house parameters and individuals' susceptibility.

  18. Emission of volatile sulfur compounds from spruce trees

    SciTech Connect

    Rennenberg, H.; Huber, B.; Schroeder, P.; Stahl, K.; Haunold, W.; Georgil, H.W.; Slovik, S.; Pfanz, H. (Fraunhofer Institut fuer Atmosphaerische Umweltforschung, Garmisch-Partenkirchen (West Germany))

    1990-03-01

    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, H{sub 2}S 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 H{sub 2}S emission increased exponentially with increasing water vapor flux from the needles. Approximately 1 nanomole of H{sub 2}S was found to be emitted per mole of water. When stomata were closed completely, only minute emission of H{sub 2}S was observed. Apparently, H{sub 2}S 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, SO{sub 2} was the only sulfur compound consistently emitted from branches of spruce trees in addition to H{sub 2}S. Emission of SO{sub 2} mainly proceeded via an outburst starting before the beginning of the light period. The total amount of SO{sub 2} 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 SO{sub 2} are discussed.

  19. Modeling Emissions of Volatile Organic Compounds from New Carpets

    SciTech Connect

    Little, J.C.; Hodgson, A.T.; Gadgil, A.J.

    1993-02-01

    A simple model is proposed to account for observed emissions of volatile organic compounds (VOCs) from new carpets. The model assumes that the VOCs originate predominantly in a uniform slab of polymer backing material. Parameters for the model (the initial concentration of a VOC in the polymer, a diffusion coefficient and an equilibrium polymer/air partition coefficient) are obtained from experimental data produced by a previous chamber study. The diffusion coefficients generally decrease as the molecular weight of the VOCs increase, while the polymer/air partition coefficients generally increase as the vapor pressure of the compounds decrease. In addition, for two of the study carpets that have a styrene-butadiene rubber (SBR) backing, the diffusion and partition coefficients are similar to independently reported values for SBR. The results suggest that predictions of VOCs emissions from new carpets may be possible based solely on a knowledge of the physical properties of the relevant compounds and the carpet backing material. However, a more rigorous validation of the model is desirable.

  20. Determination of urban volatile organic compound emission ratios and comparison with an emissions database

    NASA Astrophysics Data System (ADS)

    Warneke, C.; McKeen, S. A.; de Gouw, J. A.; Goldan, P. D.; Kuster, W. C.; Holloway, J. S.; Williams, E. J.; Lerner, B. M.; Parrish, D. D.; Trainer, M.; Fehsenfeld, F. C.; Kato, S.; Atlas, E. L.; Baker, A.; Blake, D. R.

    2007-05-01

    During the NEAQS-ITCT2k4 campaign in New England, anthropogenic VOCs and CO were measured downwind from New York City and Boston. The emission ratios of VOCs relative to CO and acetylene were calculated using a method in which the ratio of a VOC with acetylene is plotted versus the photochemical age. The intercept at the photochemical age of zero gives the emission ratio. The so determined emission ratios were compared to other measurement sets, including data from the same location in 2002, canister samples collected inside New York City and Boston, aircraft measurements from Los Angeles in 2002, and the average urban composition of 39 U.S. cities. All the measurements generally agree within a factor of two. The measured emission ratios also agree for most compounds within a factor of two with vehicle exhaust data indicating that a major source of VOCs in urban areas is automobiles. A comparison with an anthropogenic emission database shows less agreement. Especially large discrepancies were found for the C2-C4 alkanes and most oxygenated species. As an example, the database overestimated toluene by almost a factor of three, which caused an air quality forecast model (WRF-CHEM) using this database to overpredict the toluene mixing ratio by a factor of 2.5 as well. On the other hand, the overall reactivity of the measured species and the reactivity of the same compounds in the emission database were found to agree within 30%.

  1. How do emission patterns in megacities affect regional air pollution?

    NASA Astrophysics Data System (ADS)

    Heil, A.; Richter, C.; Schroeder, S.; Schultz, M. G.

    2010-12-01

    Megacities around the world show distinctly different emission patterns in terms of absolute amounts and emission ratios of individual chemical compounds due to varying socio-economic developments and technological standards. The emission patterns influence the chemical reactivity of the urban pollution plume, and hence determine air quality in and around megacity areas. In this study, which is part of the European project CITYZEN (megaCITY - Zoom for the ENvironment), the effects of emission changes in four selected megacity areas on air pollution were investigated: BeNeLux (BNL), Istanbul (IST), Pearl River Delta (PRD) and Sao Paulo (SAP). The study aims at answering the question: how would air pollution in megacity X change if it had the same urban emissions per capita as megacity Y? Model simulations with the global chemistry climate model ECHAM5-MOZ were carried out for the year 2001 using a resolution of about 2 degrees in the horizontal and of 31 levels (surface to 10 hPa) in the vertical. The model was driven by meteorological input data from the ECMWF ERA Interim reanalysis. Emissions were taken from the gridded global ACCMIP emission inventory recently established for use in chemistry-climate simulations in connection to the IPCC-AR5 assessments (Lamarque et al. 2010). We carried out sensitivity simulations where emission patterns from each of the megacity areas were replaced by those from all others. This was done on the basis of the per capita emissions for each species and sector averaged over the respective region. Total per capita CO and NMVOC emissions are highest in PRD and lowest in SAP while total per capita NOx emissions are highest in BNL and lowest in SAP. There are strong differences in the relative contribution of the urban sectors to total emissions of individual compounds. As a result, each of the four megacity areas exhibits a very characteristic NMVOC speciation profile which determines the NMVOC-related photochemical ozone (O_3) creation potential. Compared to the emissions used in the reference simulation, changing per capita urban emissions in BNL into those of IST or SAP will lead to reduction in total megacity emissions of CO and NOx by between 40 to 80% and of between 5 to 20% for NMVOC. When the per capita emissions for PRD are applied, only NOx decreases (by 50%) while CO and NMVOC increase by between 20 and 40%. Similar changes occur when the emissions are interchanged in the other three regions. Annual mean ambient O_3 concentrations in the entire BNL megacity domain are elevated by 3 to 8 ppb in all sensitivity runs and a significant effect is also found outside the main megacity area. In the IST and PRD megacity areas, O_3 levels increase or decrease by 1 to 5 ppb when the per capita emissions from the other regions are used. For the SAP megacity area, all scenarios lead to a reduction of annual mean O_3 levels by more than 4 ppb in the north-western section of the domain while increases up to 3 ppb are predicted for some southern regions. We will also present an analysis of changes in the photochemical regimes related to altered emission patterns. The study can contribute directly to the development of air pollution abatement strategies.

  2. Identification of nonmethane organic compound emissions from grassland vegetation.

    SciTech Connect

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

    2000-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  4. NATURAL VOLATILE ORGANIC COMPOUND EMISSION RATE ESTIMATES FOR U.S. WOODLAND LANDSCAPES

    EPA Science Inventory

    Volatile organic compound (VOC) emission rate factors are estimated for 49 tree genera based on a review of foliar emission rate measurements. oliar VOC emissions are grouped into three categories: isoprene, monoterpenes and other VOC'S. ypical emission rates at a leaf temperatur...

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

    E-print Network

    Silver, Whendee

    organic compounds (VOC) are oxidized in the troposphere. There are three possible final stages or out] Oxidation products of primary VOC emissions tend to become less volatile and more soluble becauseEmission, oxidation, and secondary organic aerosol formation of volatile organic compounds

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

    Microsoft Academic Search

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

    2009-01-01

    The contribution of biogenic volatile organic compounds (BVOCs) to oxidant concentrations and secondary organic aerosol (SOA) production in forested environments depends on the emission rates of these compounds. Recent findings have suggested that the emission rates of BVOCs and the range of species emitted could be larger than previously thought. In this study, Proton Transfer Reaction Mass Spectrometry (PTR-MS) was

  7. Predicting the emission rate of volatile organic compounds fromvinyl flooring

    SciTech Connect

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

    2001-03-01

    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.

  8. C 1-C 8 volatile organic compounds in the atmosphere of Hong Kong: Overview of atmospheric processing and source apportionment

    NASA Astrophysics Data System (ADS)

    Guo, H.; So, K. L.; Simpson, I. J.; Barletta, B.; Meinardi, S.; Blake, D. R.

    We present measurements of C 1-C 8 volatile organic compounds (VOCs) at four sites ranging from urban to rural areas in Hong Kong from September 2002 to August 2003. A total of 248 ambient VOC samples were collected. As expected, the urban and sub-urban sites generally gave relatively high VOC levels. In contrast, the average VOC levels were the lowest in the rural area. In general, higher mixing ratios were observed during winter/spring and lower levels during summer/fall because of seasonal variations of meteorological conditions. A variation of the air mass composition from urban to rural sites was observed. High ratios of ethyne/CO (5.6 pptv/ppbv) and propane/ethane (0.50 pptv/pptv) at the rural site suggested that the air masses over the territory were relatively fresh as compared to other remote regions. The principal component analysis (PCA) with absolute principal component scores (APCS) technique was applied to the VOC data in order to identify and quantify pollution sources at different sites. These results indicated that vehicular emissions made a significant contribution to ambient non-methane VOCs (NMVOCs) levels in urban areas (65±36%) and in sub-urban areas (50±28% and 53±41%). Other sources such as petrol evaporation, industrial emissions and solvent usage also played important roles in the VOC emissions. At the rural site, almost half of the measured total NMVOCs were due to combustion sources (vehicular and/or biomass/biofuel burning). Petrol evaporation, solvent usage, industrial and biogenic emissions also contributed to the atmospheric NMVOCs. The source apportionment results revealed a strong impact of anthropogenic VOCs to the atmosphere of Hong Kong in both urban/sub-urban and rural areas.

  9. Temporal variation of trace compound emission on the working surface of a landfill in Beijing, China

    NASA Astrophysics Data System (ADS)

    Duan, Zhenhan; Lu, Wenjing; Li, Dong; Wang, Hongtao

    2014-05-01

    The temporal variation of trace component emissions from the working surface of a landfill in Beijing was investigated. Specific days in a year were selected as representatives for all four seasons. Different chemical species were quantified in all four seasons with the following average concentrations: spring: 41 compounds, 2482.6 ?g m-3; summer: 59 compounds, 4512.6 ?g m-3; fall: 66 compounds, 2438.4 ?g m-3; and winter: 54 compounds, 2901 ?g m-3. The detected compounds included sulfur compounds, oxygenated compounds, aromatics, hydrocarbons, halogenated compounds, and terpenes. Oxygenated compounds were the most abundant compound in most samples. Isobutane, ethyl alcohol, limonene, butane, toluene, and trichlorofluoromethane were recognized as the most abundant compounds on the working surface throughout the year. This study would bring new light in assessing the particle pollution in urban areas and the effect of trace components on landfill odor.

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

    Microsoft Academic Search

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

    2003-01-01

    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.

  11. Biogenic emissions of volatile organic compounds from gorse ( Ulex europaeus ): Diurnal emission fluxes at Kelling Heath, England

    Microsoft Academic Search

    X.-L. Cao; C. Boissard; A. J. Juan; C. N. Hewitt; M. Gallagher

    1997-01-01

    Volatile organic compound (VOC) emission fluxes from Gorse (Ulex europaeus) were measured during May 30-31, 1995 at Kelling Heath in eastern England by using bag enclosure and gradient methods simultaneously. The enclosure measurements were made from branches at different stages of physiological development (flowering, after flowering, and mixed). Isoprene was found to represent 90% of the total VOC emissions, and

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

    SciTech Connect

    Fehsenfeld, F.; Trainer, M. (National Oceanic and Atmospheric Administration, Boulder, CO (United States) Univ. of Colorado, Boulder (United States)); Calvert, J.; Guenther, A.B.; Zimmerman, P. (National Center for Atmospheric Research, Boulder, CO (United States)); Fall, R. (Univ. of Colorado, Boulder (United States)); Goldan, P.; Liu, S. (National Oceanic and Atmospheric Administration, Boulder, CO (United States)); Hewitt, C.N. (Lancaster Univ. (United Kingdom)); Lamb, B.; Westberg, H. (Washington State Univ., Pullman (United States))

    1992-12-01

    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[sup -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. 197 refs., 25 figs., 7 tabs.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  14. 77 FR 14324 - National Volatile Organic Compound Emission Standards for Aerosol Coatings-Addition of Dimethyl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ...is a rule that establishes national reactivity-based emission standards for the aerosol coatings category (aerosol spray paints) under the Clean Air Act. This proposed action adds three compounds: dimethyl carbonate, benzotrifluoride, and...

  15. A screening assessment of emissions of volatile organic compounds and particles from heated indoor dust samples.

    PubMed

    Pedersen, E K; Bjørseth, O; Syversen, T; Mathiesen, M

    2003-06-01

    This paper characterizes and compares emissions during heating of different dust samples relevant to the indoor environment. Characterization includes emission of volatile organic compounds when dust samples were heated to 150 and 250 degrees C (gas chromatograph-mass spectrometer), weight loss during heating to 450 degrees C (thermogravimetric analysis), and the number of particles emitted during heating towards 200 degrees C (condensation nucleus counting). Element analyses were performed for non-heated dust (inductively coupled plasma discharge instrument). Emissions of volatile organic compounds from heated dust from different sources were surprisingly similar. However, the temperature at which the emission of volatiles started varied with the dust source. For most of the samples studied, the emissions were considerable already at 150 degrees C, and increased in number of peaks and peak area at 250 degrees C. Particle emissions started around 70 degrees C regardless of the dust source. Particle emissions seemed to be affected by the content of organic material. PMID:12756004

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

    Microsoft Academic Search

    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

    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

  17. 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 ...

  18. Volatile organic compound emissions from switchgrass cultivars used as biofuel crops

    Microsoft Academic Search

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

    2011-01-01

    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,

  19. Effects of oxygenated blending compounds on emissions from a turbocharged direct injection diesel engine

    Microsoft Academic Search

    T Litzinger; M Stoner; H Hess; A Boehman

    2000-01-01

    An experimental investigation was conducted to evaluate the effect of three different oxygenated compounds, diglyme, diethyl maleate and dibutyl maleate, on emissions from a Volkswagen 1.9 litre, turbocharged, direct injection diesel engine. Sampling was performed using a mini-dilution tunnel technique to obtain particulate matter and a Fourier transform infrared (FTIR) spectrometer for gaseous emissions. The particulate samples were analysed using

  20. RECONCILING URBAN VOC/NOX (VOLATILE ORGANIC COMPOUNDS/NOX) EMISSION INVENTORIES WITH AMBIENT CONCENTRATION DATA

    EPA Science Inventory

    A review of the current state of emission inventories of volatile organic compounds (VOC) and NOx data compiled for urban areas in the U.S. is presented. The study reveals great differences in the gross emission magnitudes when compared with corresponding ambient air concentratio...

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

    Microsoft Academic Search

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

    1998-01-01

    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

  2. Industrial waste-water volatile organic compound emissions. Background information for BACT\\/LAER determinations

    Microsoft Academic Search

    J. Elliott; S. Watkins

    1990-01-01

    The purpose of the Control Technology Center (CTC) is to provide technical information to States on estimating and controlling volatile organic compounds (VOC) emissions from the collection and treatment of industrial wastewaters for Best Available Control Technology (BACT) and Lowest Achievable Emission Rate (LAER) determinations. Technical guidance projects, focus on topics of national or regional interest that are identified through

  3. VOLATILE ORGANIC COMPOUND EMISSION PROJECTION MODEL (VERSION 1.8). USER'S MANUAL

    EPA Science Inventory

    The report discusses a model that can be used to estimate future emissions of volatile organic compounds (VOCs) and costs of their control by applying growth factors, emission constraints, control cost functions, and capacity retirement rates to the base line estimates of VOC emi...

  4. Measurements of biogenic non-methane organic compound emissions from grasslands

    SciTech Connect

    Fukui, Yoshiko

    1994-12-31

    Non-methane organic compounds (NMOCs) play an important role in the formation of photochemical oxidants in the troposphere. NMOCs originate from both anthropogenic and biogenic sources. Many organic compounds of biogenic origins are more reactive than those of anthropogenic origin because of the presence of internal double bonds within their molecular structure. The objective of this investigation was to examine the seasonal variation of NMOC emissions from grasslands and determine the environmental factors that control the emissions. An enclosure system was chosen as the most appropriate sampling technique for measuring emissions from herbaceous vegetation, and an analysis method using cryogenic preconcentration/high resolution gas chromatography was established. Emission rates were measured at a fixed location in a natural grassland during 1992 and 1993. Measurements were also made at various locations within the same site where the vegetation was harvested after the emission rates were determined. Emission rates of NMOCs for grasslands are not as large as those reported for forests. However the emissions of oxygenated hydrocarbons exceeded the emissions of monoterpenes and have not previously been identified as important forest-type emissions. A framework for parameterizing the NMOC emissions from grasslands based on seasonal and instantaneous variations of the emission rate measurements was developed. Temperature, hypoxia induced by water saturated soil, and frost were key environmental factors affecting both the composition and magnitude of NMOC emissions.

  5. Reconciling urban VOC/NOx (volatile organic compounds/NOx) emission inventories with ambient concentration data

    SciTech Connect

    Ching, J.K.S.; Novak, J.H.; Schere, K.L.; Gillani, N.V.

    1987-06-01

    A review of the current state of emission inventories of volatile organic compounds (VOC) and NOx data compiled for urban areas in the U.S. is presented. The study reveals great differences in the gross-emission magnitudes when compared with corresponding ambient-air concentration data. The VOC emissions data are, in general, shown to be underestimated by factors exceeding 3 or more for most cities. The aggregated emission from urban areas is determined from measurements of excess crosswind and vertically integrated pollutant concentration over background in the urban plume just downwind of the emissions area.

  6. Chemiluminescence (CL) emission generated during oxidation of pyrogallol and its application in analytical chemistry. I. Effect of oxidant compound

    Microsoft Academic Search

    Nicholaos P. Evmiridis; Nicholaos K. Thanasoulias; Athanasios G. Vlessidis

    1998-01-01

    An investigation of chemiluminescence (CL)-emission generated by the oxidation of pyrogallol using various inorganic oxidant compounds is reported in this F.I.A.-merging zone application. The oxidant compounds that showed measurable CL-emission were permanganate, periodate, hypochlorite anions, cerium(IV) and hydrogen peroxide. The different oxidant compounds showed CL-emissions at different pH-ranges. The CL-emission was limited by the inner filter effect and this was

  7. Effects of bulking agent addition on odorous compounds emissions during composting of OFMSW.

    PubMed

    Shao, Li-Ming; Zhang, Chun-Yan; Wu, Duo; Lü, Fan; Li, Tian-Shui; He, Pin-Jing

    2014-08-01

    The effects of rice straw addition level on odorous compounds emissions in a pilot-scale organic fraction of municipal solid waste (OFMSW) composting plant were investigated. The cumulative odorous compounds emissions occurred in a descending order of 40.22, 28.71 and 27.83 mg/dry kg of OFMSW for piles with rice straw addition level at ratio of 1:10, 2:10 and 3:10 (mixing ratio of rice straw to OFMSW on a wet basis), respectively. The mixing ratio of rice straw to OFMSW had a statistically significant effect on the reduction of malodorous sulfur compounds emissions, which had no statistically significant effect on the reduction of VFAs, alcohols, aldehydes, ketones, aromatics and ammonia emissions during composting, respectively. The cumulative emissions of malodorous sulfur compounds from piles with the increasing rice straw addition level were 1.17, 1.08 and 0.88 mg/dry kg of OFMSW, respectively. The optimal mixing ratio of rice straw to OFMSW was 1:5. Using this addition level, the cumulative malodorous sulfur compounds emissions based on the organic matter degradation were the lowest during composting of OFMSW. PMID:24820662

  8. Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin.

    PubMed

    Momoshima, N; Song, L X; Osaki, S; Maeda, Y

    2001-07-15

    We observed biologically mediated emission of Po from culture solution inoculated sea sediment extract and incubated under natural light/dark cycle condition or dark condition the emitted Po compound would be lipophilic because of effective collection in organic solvent. Sterilization of the culture medium with antibiotics or CuSO4 completely suppressed growth of microorganisms and resulted in no emission of Po, indicating biological activity of microorganisms is responsible for formation and emission of volatile Po compound. Po emission also occurred when seawater was used as a culture medium. Our finding indicates a possibility of biotic source for atmospheric Po in the environment, which has been believed to be originated from abiotic sources. We compared emission behavior of Po and S in the culture experiments, the elements belong to XVI group in the Periodical Table, and consider that their emission mechanisms involved would be different though the emission of both elements is supported by biological activity of microorganisms. One of the chemical forms of S emitted was confirmed to be dimethyl sulfide (DMS) but that of Po is not known. Methylation experiments of Po with methylcobalamin demonstrated a formation and emission of volatile Po compound. The methylation of Po with methylcobalamin might be related to the observed Po emission in the culture experiments. PMID:11478248

  9. Speciation of aromatic compounds with excitation-emission matrix measurements

    Microsoft Academic Search

    Jane W. Pepper; Yu-Min Chen; Andrew O. Wright; Jonathan E. Kenny

    1999-01-01

    Research in our group has shown that a multiple channel laser-induced fluorescence (LIF) system is an effective tool for in situ monitoring of polyaromatic hydrocarbons (PAHs). The system delivers ten laser beams to a samples and simultaneously detects the fluorescence signals from the individual channels, generating an excitation-emission matrix (EEM) of the sample. Speciation of chemical present in a mixture

  10. Toxic volatile organic compounds in environmental tobacco smoke: Emission factors for modeling exposures of California populations

    SciTech Connect

    Daisey, J.M.; Mahanama, K.R.R.; Hodgson, A.T. [Lawrence Berkeley Lab., CA (United States)

    1994-10-01

    The primary objective of this study was to measure emission factors for selected toxic air contaminants 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-nitrosamines 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 ({mu}g/cigarette) 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.

  11. Development of a test method for carbonyl compounds from stationary source emissions

    SciTech Connect

    Zhihua Fan; Peterson, M.R.; Jayanty, R.K.M. [Research Triangle Institute, Research Triangle Park, NC (United States)

    1997-12-31

    Carbonyl compounds have received increasing attention because of their important role in ground-level ozone formation. The common method used for the measurement of aldehydes and ketones is 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by high performance liquid chromatography and ultra violet (HPLC-UV) analysis. One of the problems associated with this method is the low recovery for certain compounds such as acrolein. This paper presents a study in the development of a test method for the collection and measurement of carbonyl compounds from stationary source emissions. This method involves collection of carbonyl compounds in impingers, conversion of carbonyl compounds to a stable derivative with O-2,3,4,5,6-pentafluorobenzyl hydroxylamine hydrochloride (PFBHA), and separation and measurement by electron capture gas chromatography (GC-ECD). Eight compounds were selected for the evaluation of this method: formaldehyde, acetaldehyde, acrolein, acetone, butanal, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and hexanal.

  12. Speciation of organotin and organolead compounds in drinking water by gas chromatography — atomic emission spectrometry

    Microsoft Academic Search

    Abdel-ilah Sadiki; David T. Williams

    1996-01-01

    Raw and treated water samples and distribution system water samples were collected in forty-five Canadian municipalities for the analysis of organotin and organolead compounds. After extraction from the water samples organotin and organolead compounds were alkylated with pentylmagnesium bromide and butylmagnesium chloride respectively and analysed by gas chromatography-microwave induced plasma atomic emission spectrometry (GC-AED) using wavelengths specific for tin (326.23

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

    NASA Astrophysics Data System (ADS)

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

    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.

  14. Production and Emission of Volatile Compounds by Petal Cells

    PubMed Central

    Caissard, Jean-Claude; Bergougnoux, Véronique; Jullien, Frédéric; Magnard, Jean-Louis; Scalliet, Gabriel; Cock, J Mark; Hugueney, Philippe

    2007-01-01

    We localized the tissues and cells that contribute to scent biosynthesis in scented and non-scented Rosa × hybrida cultivars as part of a detailed cytological analysis of the rose petal. Adaxial petal epidermal cells have a typical conical, papillate shape whereas abaxial petal epidermal cells are flat. Using two different techniques, solid/liquid phase extraction and headspace collection of volatiles, we showed that, in roses, both epidermal layers are capable of producing and emitting scent volatiles, despite the different morphologies of the cells of these two tissues. Moreover, OOMT, an enzyme involved in scent molecule biosynthesis, was localized in both epidermal layers. These results are discussed in view of results found in others species such as Antirrhinum majus, where it has been shown that the adaxial epidermis is the preferential site of scent production and emission. PMID:19704548

  15. Volatile organic compound emissions from usaf wastewater treatment plants in ozone nonattainment areas. Master's thesis

    Microsoft Academic Search

    Ouellette

    1994-01-01

    In accordance with the 1990 Clean Air Act Amendments (CAAA), this research conducts an evaluation of the potential emission of volatile organic compounds (VOCs) from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which

  16. Plant-specific volatile organic compound emission rates from young and mature leaves of Mediterranean vegetation

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

    The seasonality of vegetation, i.e., developmental stages and phenological processes, affects the emission of volatile organic compounds (VOCs). Despite the potential significance, the contributions of seasonality to VOC emission quality and quantity are not well understood and are therefore often ignored in emission simulations. We investigated the VOC emission patterns of young and mature leaves of several Mediterranean plant species in relation to their physiological and developmental changes during the growing period and estimated Es. Foliar emissions of isoprenoids and oxygenated VOCs like methanol and acetone were measured online by means of a proton transfer reaction mass spectrometer (PTR-MS) and offline with gas chromatography coupled with a mass spectrometer and flame ionization detector. The results suggest that VOC emission is a developmentally regulated process and that quantitative and qualitative variability is plant species specific. Leaf ontogeny clearly influenced both the VOC Es and the relative importance of different VOCs. Methanol was the major compound contributing to the sum of target VOC emissions in young leaves (11.8 ± 10.4 ?g g-1 h-1), while its contribution was minor in mature leaves (4.1 ± 4.1 ?g g-1 h-1). Several plant species showed a decrease or complete subsidence of monoterpene, sesquiterpene, and acetone emissions upon maturity, perhaps indicating a potential response to the higher defense demands of young emerging leaves.

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

    PubMed

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

    2014-06-01

    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

  18. Emission control of sodium compounds and their formation mechanisms during coal combustion

    SciTech Connect

    Tsuyoshi Takuwa; Ichiro Naruse [Toyohashi University of Technology, Toyohashi (Japan). Department of Ecological Engineering

    2007-07-01

    In order to control emissions of sodium compounds during coal combustion, the sorbent injection technology is tested during coal combustion. Kaolin is selected as the sorbent to absorb vapors of sodium compounds evolved from the coals. In the combustion experiments, the kaolin is physically mixed with coal. Two types of coal, which have the similar coal properties, are burned. Combustion tests are conducted, using an electrically heated drop tube furnace, to study effect of kaolin addition on the capture characteristics of sodium compounds. In order to elucidate fundamentals on transformation behaviors of sodium compounds during hydrogen-air combustion, chemical kinetic simulation by elementary reactions relating to sodium compounds is also performed, varying the reaction atmosphere. As a result, the kaolin can effectively capture the vapor of sodium compounds even during coal combustion. The capture efficiency depends on the coal type. The sodium compounds for the coals, which produce many fine particles with size of less than 1 {mu}m, tend to be effectively captured by the kaolin. According to the kinetic simulation of sodium species, difference of the reaction atmosphere affects occurrence species of sodium vapor. In the combustion region, the sodium compounds become metallic sodium vapor in any reaction atmospheres due to occurrence of the reducing radical species. HCl gas rather than SO{sub 2} gas plays an important role to transform gaseous sodium compounds. 44 refs., 8 figs., 3 tabs.

  19. Biogenic volatile organic compounds (BVOCs) emissions from Abies alba in a French forest.

    PubMed

    Moukhtar, S; Couret, C; Rouil, L; Simon, V

    2006-02-01

    Air quality studies need to be based on accurate and reliable data, particularly in the field of the emissions. Biogenic emissions from forests, crops, and grasslands are now considered as major compounds in photochemical processes. Unfortunately, depending on the type of vegetation, these emissions are not so often reliably defined. As an example, although the silver fir (Abies alba) is a very widespread conifer tree in the French and European areas, its standard emission rate is not available in the literature. This study investigates the isoprene and monoterpenes emission from A. alba in France measured during the fieldwork organised in the Fossé Rhénan, from May to June 2003. A dynamic cuvette method was used. Limonene was the predominant monoterpene emitted, followed by camphene, alpha-pinene and eucalyptol. No isoprene emission was detected. The four monoterpenes measured showed different behaviours according to micrometeorological conditions. In fact, emissions of limonene, alpha-pinene and camphene were temperature-dependant while eucalyptol emissions were temperature and light dependant. Biogenic volatile organic compounds emissions were modeled using information gathered during the field study. Emissions of the three monoterpenes previously quoted were achieved using the monoterpenes algorithm developed by Tingey et al. (1980) [Tingey D, Manning M, Grothaus L, Burns W. Influence of light and temperature on monoterpene emission rates from slash pine. Plant Physiol 1980;65: 797-801.] and the isoprene algorithm [Guenther, A., Monson, R., Fall, R., 1991. Isoprene and monoterpene emission rate variability: observations with eucalyptus and emission rate algorithm development. J Geophys Res 26A: 10799-10808.]; [Guenther, A., Zimmerman, P., Harley, P., Monson, R., Fall, R., 1993. Isoprene and monoterpene emission rate variability: model evaluation and sensitivity analysis. J Geophys Res 98D: 12609-12617.]) was used for the eucalyptol emission. With these methods, simulation results and observations agreed fairly well. The standard emission rate (303 K) and beta-coefficient averaged for limonene, camphene and alpha-pinene were respectively of 0.63 microg gdw-1 h-1 and 0.06 K-1. For eucalyptol, the standard emission rate (T=303 K and PAR=1000 micromol m-2 s-1) was 0.26 microg gdw-1 h-1. This classified A. alba as a weak monoterpenes emitter. PMID:16140360

  20. 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...

  1. 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...

  2. 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...

  3. Characterizing and mitigating emissions of volatile organic compounds from animal feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile organic compounds (VOC) emitted from animal feeding operations negatively impact local and potentially regional air quality though the release of both odorous and ozone precursor molecules. Characterizing emissions of VOCs from AFOs is strongly influenced by both the method and location of ...

  4. Emission properties of porphyrin compounds in new polymeric PS:CBP host

    NASA Astrophysics Data System (ADS)

    Jafari, Mohammad Reza; Bahrami, Bahram

    2015-06-01

    In this study, a device with fundamental structure of ITO/PEDOT:PSS (60 nm)/PS:CBP (70 nm)/Al (150 nm) was fabricated. The electroluminescence spectrum of device designated a red shift rather than PS:CBP photoluminescence spectra. It can be suggested that the electroplex emission occurs at PS:CBP interface. By following this step, red light-emitting devices using porphyrin compounds as a red dopant in a new host material PS:CBP with a configuration of ITO/PEDOT:PSS (60 nm)/PS:CBP:porphyrin compounds(70 nm)/Al (150 nm) have been fabricated and investigated. The electroluminescent spectra of the porphyrin compounds were red-shifted as compared with the PS:CBP blend. OLED devices based on doping 3,4PtTPP and TPPNO2 in PS:CBP showed purer red emission compared with ZnTPP and CoTPP doped devices. We believe that the electroluminescence performance of OLED devices based on porphyrin compounds depends on overlaps between the absorption of the porphyrin compounds and the emission of PS:CBP.

  5. Volatile organic compound emissions from elephant grass and bamboo cultivars used as potential bioethanol crop

    NASA Astrophysics Data System (ADS)

    Crespo, E.; Graus, M.; Gilman, J. B.; Lerner, B. M.; Fall, R.; Harren, F. J. M.; Warneke, C.

    2013-02-01

    Volatile organic compound (VOC) emissions from elephant grass (Miscanthus gigantus) and black bamboo (Phyllostachys nigra) were measured online in semi-field chamber and plant enclosure experiments during growth and harvest using proton-transfer reaction mass spectrometry (PTR-MS), proton-transfer reaction ion-trap mass spectrometry (PIT-MS) and gas chromatography-mass spectrometry (GC-MS). Both cultivars are being considered for second-generation biofuel production. Before this study, no information was available on their yearly VOC emissions. This exploratory investigation shows that black bamboo is a strong isoprene emitter (daytime 28,516 ng gdwt-1 h-1) and has larger VOC emissions, especially for wound compounds from the hexanal and hexenal families, than elephant grass. Daytime emissions of methanol, acetaldehyde, acetone + propanal and acetic acid of black bamboo were 618, 249, 351, and 1034 ng gdwt-1 h-1, respectively. In addition, it is observed that elephant grass VOC emissions after harvesting strongly depend on the seasonal stage. Not taking VOC emission variations throughout the season for annual and perennial species into account, may lead to an overestimation of the impact on local air quality in dry periods. In addition, our data suggest that the use of perennial grasses for extensive growing for biofuel production have lower emissions than woody species, which might be important for regional atmospheric chemistry.

  6. Emissions of carbon species, organic polar compounds, potassium, and mercury from prescribed burning activities

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Obrist, D.; Zielinska, B.; Gerler, A.

    2012-04-01

    Biomass burning is an important emission source of pollutants to the atmosphere, but few studies have focused on the chemical composition of emissions from prescribed burning activities. Here we present results from a sampling campaign to quantify particulate-phase emissions from various types of prescribed fires including carbon species (Elemental Carbon: EC; Organic Carbon: OC; and Total Carbon: TC); polar organic compounds (12 different compounds and four functional classes); water-soluble potassium (K+); and mercury (Hg). We measured emissions from the following types of prescribed biomass burning in the Lake Tahoe basin located on the California/Nevada border: (i) log piles stacked and dried in the field; (ii) log piles along with green understory vegetation; and (iii) understory green vegetation and surface litter; further emissions were collected from burns conducted in a wood stove: (iv) dried wooden logs; (v) green foliage of understory vegetation collected from the field; and (vi) surface organic litter collected from the field; finally, samples were also taken from (vii) ambient air in residential areas during peak domestic wood combustion season. Results show that OC/EC ratios of prescribed burns in the field ranged from 4 to 10, but lower values (around 1) were observed in controlled stove fires. These results are consistent with an excess of OC emissions over EC found in wildfires. OC/EC ratios, however, showed clear separations between controlled wood stove combustion (higher EC) and prescribed burns in the field (lower EC). We attribute this difference to a higher combustion temperatures and dominance of flaming combustion in wood stove fires. OC positively and linearly correlated to the sum of polar organic compounds across all burn types (r2 of 0.82). The most prevalent group of polar compounds emitted during prescribed fires was resin acids (dehydroabietic, pimaric, and abietic acids), followed by levoglucosan plus mannositol. Negligible contributions were observed for inositols, arabitols, and lignin derivates. Although some of these polar compound classes are linked to specific woody or green tissues, we found no significant differences of emission ratios between different types of fires. Water-soluble K+, a common tracer for biomass combustion, showed a clear separation between understory burns (low K+) and wooden pile burns (10 to 20 times higher), suggesting that K+ can potentially be used for differentiating between green versus dry, wooden biomass combustion. Finally, Hg emissions were very low across all fire emissions collected, but were enhanced in urban air sampling which might allow for differentiating sources from biomass combustion from other urban sources.

  7. Existing Pittsburgh Compound-B positron emission tomography thresholds are too high: statistical and pathological evaluation.

    PubMed

    Villeneuve, Sylvia; Rabinovici, Gil D; Cohn-Sheehy, Brendan I; Madison, Cindee; Ayakta, Nagehan; Ghosh, Pia M; La Joie, Renaud; Arthur-Bentil, Samia Kate; Vogel, Jacob W; Marks, Shawn M; Lehmann, Manja; Rosen, Howard J; Reed, Bruce; Olichney, John; Boxer, Adam L; Miller, Bruce L; Borys, Ewa; Jin, Lee-Way; Huang, Eric J; Grinberg, Lea T; DeCarli, Charles; Seeley, William W; Jagust, William

    2015-07-01

    Amyloid-?, a hallmark of Alzheimer's disease, begins accumulating up to two decades before the onset of dementia, and can be detected in vivo applying amyloid-? positron emission tomography tracers such as carbon-11-labelled Pittsburgh compound-B. A variety of thresholds have been applied in the literature to define Pittsburgh compound-B positron emission tomography positivity, but the ability of these thresholds to detect early amyloid-? deposition is unknown, and validation studies comparing Pittsburgh compound-B thresholds to post-mortem amyloid burden are lacking. In this study we first derived thresholds for amyloid positron emission tomography positivity using Pittsburgh compound-B positron emission tomography in 154 cognitively normal older adults with four complementary approaches: (i) reference values from a young control group aged between 20 and 30 years; (ii) a Gaussian mixture model that assigned each subject a probability of being amyloid-?-positive or amyloid-?-negative based on Pittsburgh compound-B index uptake; (iii) a k-means cluster approach that clustered subjects into amyloid-?-positive or amyloid-?-negative based on Pittsburgh compound-B uptake in different brain regions (features); and (iv) an iterative voxel-based analysis that further explored the spatial pattern of early amyloid-? positron emission tomography signal. Next, we tested the sensitivity and specificity of the derived thresholds in 50 individuals who underwent Pittsburgh compound-B positron emission tomography during life and brain autopsy (mean time positron emission tomography to autopsy 3.1 ± 1.8 years). Amyloid at autopsy was classified using Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria, unadjusted for age. The analytic approaches yielded low thresholds (standard uptake value ratiolow = 1.21, distribution volume ratiolow = 1.08) that represent the earliest detectable Pittsburgh compound-B signal, as well as high thresholds (standard uptake value ratiohigh = 1.40, distribution volume ratiohigh = 1.20) that are more conservative in defining Pittsburgh compound-B positron emission tomography positivity. In voxel-wise contrasts, elevated Pittsburgh compound-B retention was first noted in the medial frontal cortex, then the precuneus, lateral frontal and parietal lobes, and finally the lateral temporal lobe. When compared to post-mortem amyloid burden, low proposed thresholds were more sensitive than high thresholds (sensitivities: distribution volume ratiolow 81.0%, standard uptake value ratiolow 83.3%; distribution volume ratiohigh 61.9%, standard uptake value ratiohigh 62.5%) for CERAD moderate-to-frequent neuritic plaques, with similar specificity (distribution volume ratiolow 95.8%; standard uptake value ratiolow, distribution volume ratiohigh and standard uptake value ratiohigh 100.0%). A receiver operator characteristic analysis identified optimal distribution volume ratio (1.06) and standard uptake value ratio (1.20) thresholds that were nearly identical to the a priori distribution volume ratiolow and standard uptake value ratiolow. In summary, we found that frequently applied thresholds for Pittsburgh compound-B positivity (typically at or above distribution volume ratiohigh and standard uptake value ratiohigh) are overly stringent in defining amyloid positivity. Lower thresholds in this study resulted in higher sensitivity while not compromising specificity. PMID:25953778

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

    NASA Astrophysics Data System (ADS)

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

    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 of the dominant compounds were found during this survey. Emissions from Q. suber were strongly dependent on light and temperature, showing a similar behaviour to that of plant species known to be isoprene producers. But, this work also revealed that, although at lower rates, emissions of monoterpenes continued in the dark for several hours. Emission rates were quite well predicted by algorithms based on the Guenther and Tingey equations; correlations of measurements with modelled data were, on average, r2=0.80. A pronounced seasonal variation was recorded for the emissions of monoterpenes. During the 1-yr study period, standard emission rates ranged between a minimum of 0.2 ?g g dw-1 h -1, in winter, and a maximum of 20-30 ?g g dw-1 h -1, in summer.

  9. Characterization of emissions of volatile organic compounds from interior alkyd paint.

    PubMed

    Fortmann, R; Roache, N; Chang, J C; Guo, Z

    1998-10-01

    Alkyd paint continues to be used indoors for application to wood trim, cabinet surfaces, and some kitchen and bathroom walls. Alkyd paint may represent a significant source of volatile organic compounds (VOCs) indoors because of the frequency of use and amount of surface painted. The U.S. Environmental Protection Agency (EPA) is conducting research to characterize VOC emissions from paint and to develop source emission models that can be used for exposure assessment and risk management. The technical approach for this research involves both analysis of the liquid paint to identify and quantify the VOC contents and dynamic small chamber emissions tests to characterize the VOC emissions after application. The predominant constituents of the primer and two alkyd paints selected for testing were straight-chain alkanes (C9-C12); C8-C9 aromatics were minor constituents. Branched chain alkanes were the predominant VOCs in a third paint. A series of tests were performed to evaluate factors that may affect emissions following application of the coatings. The type of substrate (glass, wallboard, or pine board) did not have a substantial impact on the emissions with respect to peak concentrations, the emissions profile, or the amount of VOC mass emitted from the paint. Peak concentrations of total volatile organic compounds (TVOCs) as high as 10,000 mg/m3 were measured during small chamber emissions tests at 0.5 air exchanges per hour (ACH). Over 90% of the VOCs were emitted from the primer and paints during the first 10 hr following application. Emissions were similar from paint applied to bare pine board, a primed board, or a board previously painted with the same paint. The impact of other variable, including film thickness, air velocity at the surface, and air-exchange rate (AER) were consistent with theoretical predictions for gas-phase, mass transfer-controlled emissions. In addition to the alkanes and aromatics, aldehydes were detected in the emissions during paint drying. Hexanal, the predominant aldehyde in the emissions, was not detected in the liquid paint and was apparently an oxidation product formed during drying. This paper summarizes the results of the product analyses and a series of small chamber emissions tests. It also describes the use of a mass balance approach to evaluate the impact of test variables and to assess the quality of the emissions data. PMID:9798433

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

    E-print Network

    Chance, Kelly

    a continuous 6-year record (1996­2001) of GOME satellite measurements of formaldehyde (HCHO) columns over east (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

  11. Volatile organic compound emissions from usaf wastewater treatment plants in ozone nonattainment areas. Master's thesis

    SciTech Connect

    Ouellette, B.A.

    1994-09-01

    In accordance with the 1990 Clean Air Act Amendments (CAAA), this research conducts an evaluation of the potential emission of volatile organic compounds (VOCs) from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which represent a cross section of the current inventory of USAF wastewater plants in ozone nonattainment areas. From these calculations, maximum facility emissions are determined which represent the upper limit for the potential VOC emissions from these wastewater plants. Based on the calculated emission estimates, each selected wastewater facility is evaluated as a potential major stationary source of volatile organic emissions under both Title I of the 1990 CAAA and the plant's governing Clean Air Act state implementation plan. Next, the potential impact of the specific volatile organics being emitted is discussed in terms of their relative reactivity and individual contribution to tropospheric ozone formation. Finally, a relative comparison is made between the estimated VOC emissions for the selected wastewater facilities and the total VOC emissions for their respective host installations.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  13. Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

    NASA Astrophysics Data System (ADS)

    Karl, T.; Apel, E.; Hodzic, A.; Riemer, D. D.; Blake, D. R.; Wiedinmyer, C.

    2009-01-01

    Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-median midday toluene and benzene fluxes are calculated to be on the order of 14.1±4.0 mg/m2/h and 4.7±2.3 mg/m2/h, respectively. For comparison the adjusted CAM2004 emission inventory estimates toluene fluxes of 10 mg/m2/h along the footprint of the flight-track. Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10-15 g/g) including the International airport (e.g. 3-5 g/g) and a mean flux (concentration) ratio of 3.2±0.5 g/g (3.9±0.3 g/g) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (BTEX- Benzene/Toluene/Ethylbenzene/m, p, o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH3CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >87% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds in the MCMA (2-13%).

  14. Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

    NASA Astrophysics Data System (ADS)

    Karl, T.; Apel, E.; Hodzic, A.; Riemer, D.; Blake, D.; Wiedinmyer, C.

    2008-07-01

    Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-average midday toluene and benzene fluxes are calculated to be on the order of 15.5±4.0 mg/m2/h and 4.7±2.3 mg/m2/h respectively. These values argue for an underestimation of toluene and benzene emissions in current inventories used for the Mexico City Metropolitan Area (MCMA). Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10 15) including the International airport (e.g. 3 5) and a mean flux (concentration) ratio of 3.2±0.5 (3.9±0.3) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (Benzene/Toluene/Ethylbenzene/m,p,o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH3CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >90% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds (0 10%) in the MCMA.

  15. Emission of reactive terpene compounds from orange orchards and their removal by within-canopy processes

    NASA Astrophysics Data System (ADS)

    Ciccioli, Paolo; Brancaleoni, Enzo; Frattoni, Massimiliano; di Palo, Vincenzo; Valentini, Riccardo; Tirone, Giampiero; Seufert, Guenther; Bertin, Nadia; Hansen, Ute; Csiky, Olav; Lenz, Roman; Sharma, Meeta

    1999-04-01

    VOC emission from orange orchards was determined in the framework of two field campaigns aimed at assessing the contribution of vegetation emissions to tropospheric ozone formation in the Valencia Citrus belt. Branch emission from different varieties of Citrus sinensis and Citrus Clementi was dominated by ?-caryophyllene during the summer period and by linalool during the blossoming season (April-May). Large emission of D-limonene from soil was also measured. Data collected with the enclosure technique were upscaled to determine canopy emission rates of terpene compounds. Values obtained were compared with fluxes measured by relaxed eddy accumulation. Substantial removal of ?-caryophyllene and linalool was detected during transport from the canopy into the atmospheric boundary layer. While within-canopy removal of the sesquiterpene component was fully consistent with laboratory studies indicating the high reactivity of this compound with ozone, linalool losses were more difficult to explain. Although high canopy fluxes of acetone and acetaldehyde suggested linalool decomposition by gas-phase reactivity, removal by heterogeneous chemistry seems the more likely explanation for the observed losses.

  16. Historic volatile organic compounds (VOCS) emissions estimates and activity data (for microcomputers). Data file

    SciTech Connect

    Mobley, J.D.; Gschwandtner, G.

    1988-03-31

    Lotus spreadsheets containing the data presented in Appendix B of the EPA report Historic Emissions of Volatile Organic Compounds (VOC) in the United States from 1900 to 1985 are provided on three 5 1/4 floppy diskettes. VOC emissions and activity data are given for the United States; Alabama-Florida; Georgia-Louisiana; Maine-Montana; Nebraska-North Dakota; Ohio-Tennessee; and Texas-Wyoming. The data file is in the LOTUS 1-2-3 format using the DOS 3.10 operating system.

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

    SciTech Connect

    Center for Human Reliability Studies

    2006-06-01

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

  18. Control techniques for volatile organic compound emissions from stationary sources, December 1992. Final report

    SciTech Connect

    Not Available

    1992-12-01

    The document is a summary document containing general information on sources of volatile organic compound (VOC) emissions, applicable control techniques, and the impacts resulting from control applications. It references other documents which contain much more detailed information on individual sources and control techniques. This is the third edition of a report originally published by the Department of Health, Education, and Welfare (HEW) titled, 'Control Techniques for Hydrocarbon and Organic Solvent Emissions from Stationary Sources (AP-68).' The first edition was published in March 1970 by the National Air Pollution Control Administration, a part of HEW.

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    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.

  20. Projection of anthropogenic volatile organic compounds (VOCs) emissions in China for the period 2010-2020

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Wang, Shuxiao; Hao, Jiming; Cheng, Shuiyuan

    2011-12-01

    The future (2010-2020) anthropogenic volatile organic compounds (VOCs) emissions in China were projected in this study using 2005 as the reference year. The projections are based on the assumptions of a lower population growth rate (less than 1%), continuous economic development with high GDP growth, and increased urbanization. The results show that the national VOCs emissions would continuously increase from 19.4 Tg in 2005 to 25.9 Tg in 2020, even if China's legislative standards for VOCs emissions are implemented effectively in the future (assumed as control scenario I). The contributions of various emission sources were found to differ greatly in the period of 2010-2020. Solvent utilization would become the largest contributor rising from 22% to 37%, along with an increase for industrial processes from 17% to 24%. However, road vehicle emissions would rapidly decrease from 25% to 11% due to the strict VOCs emission limit standards in China, along with the decrease for stationary fuel combustion from 23% to 16% caused by the reduction of domestic biofuel consumption. Additionally, there would be a notable divergence among provincial emissions. The developed eastern and coastal regions would emit more VOCs than the relatively underdeveloped western and inland regions. Moreover, this divergence grows in the future. When we assumed stricter control measures for solvent utilization and industrial processes (control scenario II) for that period, the projections revealed national VOCs emissions per year would remain at about 20 Tg, if exhaust after-treatment systems are installed in newly-built factories (after 2005) for the most important industrial sources, and the market shares of "low/zero-VOCs" products in paints, adhesives and printing ink raise to the present levels of developed countries. The emission abatements of the two types of measures were estimated to be similar. While scenario II indicates that the sectoral and provincial differences of VOCs emissions would still exist, they would be smaller than in scenario I.

  1. Contribution of flowering trees to urban atmospheric biogenic volatile organic compound emissions

    NASA Astrophysics Data System (ADS)

    Baghi, R.; Helmig, D.; Guenther, A.; Duhl, T.; Daly, R.

    2012-10-01

    Emissions of biogenic volatile organic compounds (BVOC) from urban trees during and after blooming were measured during spring and early summer 2009 in Boulder, Colorado. Air samples were collected onto solid adsorbent cartridges from branch enclosures on the tree species crabapple (Malus sp.), horse chestnut (Aesculus carnea, "Ft. McNair"), honey locust (Gleditsia triacanthos, "Sunburst"), and hawthorn (Crataegus laevigata, "Pauls Scarlet"). These species constitute ~ 65% of the insect-pollinated fraction of the flowering tree canopy (excluding catkin-producing trees) from the street area managed by the City of Boulder. Samples were analyzed for C10-C15 BVOC by thermal desorption and gas chromatography coupled to a flame ionization detector and a mass spectrometer (GC/FID/MS). Identified emissions and emission rates from these four tree species during the flowering phase were found to vary over a wide range. Monoterpene emissions were identified for honey locust, horse chestnut and hawthorn. Sesquiterpene emissions were observed in horse chestnut and hawthorn samples. Crabapple flowers were found to emit significant amounts of benzyl alcohol and benzaldehyde. Floral BVOC emissions increased with temperature, generally exhibiting exponential temperature dependence. Changes in BVOC speciation during and after the flowering period were observed for every tree studied. Emission rates were significantly higher during the blooming compared to the post-blooming state for crabapple and honey locust. The results were scaled to the dry mass of leaves and flowers contained in the enclosure. Only flower dry mass was accounted for crabapple emission rates as leaves appeared at the end of the flowering period. Total normalized (30 °C) monoterpene emissions from honey locust were higher during flowering (5.3 ?gC g-1 h-1) than after flowering (1.2 ?gC g-1 h-1). The total normalized BVOC emission rate from crabapple (93 ?gC g-1 h-1) during the flowering period is of the same order as isoprene emissions from oak trees, which are among the highest BVOC flowering period floral emissions observed from plants to date. These findings illustrate that during the relatively brief springtime flowering period, floral emissions constitute by far the most significant contribution to the BVOC flux from these tree species, some of which are leafless at this time. Experimental results were integrated into the MEGAN biogenic emission model and simulations were performed to estimate the contribution of floral BVOC emissions to the total urban BVOC flux during the spring flowering period. The floral BVOC emitted during this three-month simulation are equivalent to 11% of the integrated monoterpene flux for the Boulder urban area.

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

    Microsoft Academic Search

    Estela Pagans; Antoni Sánchez

    2006-01-01

    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

  3. A Study on Dynamic Volatile Organic Compound Emission Characterization of Water-Based Paints

    Microsoft Academic Search

    Yu-Min Chang; Wei-Hsing Hu; Wen-Bing Fang; Shiao-Shing Chen; Chang-Tang Chang; Hsiao-Wei Ching

    2011-01-01

    Volatile organic compounds (VOCs) emitted from surface coatings have caused growing public concern for air quality. Even the low-emitted VOC impact from water-based paints on indoor air quality in urban areas has caused concern. This paper presents experimental data using a mathematical model to simulate dynamic VOC emissions from water-based paints that is based on mass transfer and molecular diffusion

  4. Emission of sulfur-bearing compounds from motor vehicle and aircraft engines. A report to congress

    Microsoft Academic Search

    Kawecki

    1978-01-01

    This report was generated in response to section 403(g) of The Clean Air Act as amended August, 1977. The report covers (1) a review of emission factors for HâSOâ, SOâ, sulfate, HâS, and carbonyl sulfide from motor vehicles, motor vehicle engines and aircraft engines; (2) a review of the known effects on health and welfare of these compounds; (3) the

  5. Biogenic emissions of volatile organic compounds from gorse (Ulex europaeus): Diurnal emission fluxes at Kelling Heath, England

    NASA Astrophysics Data System (ADS)

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

    1997-08-01

    Volatile organic compound (VOC) emission fluxes from Gorse (Ulex europaeus) were measured during May 30-31, 1995 at Kelling Heath in eastern England by using bag enclosure and gradient methods simultaneously. The enclosure measurements were made from branches at different stages of physiological development (flowering, after flowering, and mixed). Isoprene was found to represent 90% of the total VOC emissions, and its emission rates fluctuated from 6 ng (g dwt)-1 h-1 in the early morning to about 9700 ng(g dwt)-1 h-1 at midday. Averaged emission rates standardized to 20°C were 1625, 2120, and 3700 ng (g dwt)-1 h-1 for the new grown, "mixed," and flowering branch, respectively. Trans-ocimene and ?-pinene were the main monoterpenes emitted and represented, on average, 47.6% and 36.9% of the total monoterpenes. Other monoterpenes, camphene, sabinene, ?-pinene, myrcene, limonene and ?-terpinene, were positively identified but together represented less than 1.5% of the total VOC emissions from gorse. Maximum isoprene concentrations in air at the site were measured around midday at 2 m (174 parts per trillion by volume, or pptv) and 6 m (149 pptv), and minimum concentrations were measured during the night (8 pptv at both heights). Mean daytime ?-pinene air concentrations of 141 and 60 pptv at 2 and 6 m height were determined, but trans-ocimene concentrations were less than the analytical detection limit (4 pptv), suggesting rapid chemical removal of this compound from air. The isoprene fluxes calculated by the micrometeorological gradient method showed a pattern similar to that of those calculated by the enclosure method, with isoprene emission rates maximum at midday (100 ?g m-2 h-1) and not detectable during the nighttime. Assessment of the fraction of the site covered by gorse plants enabled an extrapolation of emission fluxes from the enclosure measurements. When averaged over the 2 day experiment, isoprene fluxes of 29.8 and 27.8 ?g m-2 h-1 were obtained from the gradient and the enclosure extrapolation respectively. These isoprene fluxes to the atmosphere represented between 0.12% and 0.35% of the net assimilated carbon (as CO2) uptake rate for gorse.

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

    PubMed Central

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

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

    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.

  8. Abatement of volatile organic sulfur compounds in odorous emissions from the bio-industry.

    PubMed

    Smet, E; Van Langenhove, H

    1998-01-01

    Compounds of interest in this work are methanethiol (MeSH), dimethyl sulfide (Me2S), dimethyl polysulfides (Me2Sx) and carbon disulfide (CS2) since these volatiles have been identified as predominant odorants in the emission of a wide range of activities in the bio-industry (e.g. aerobic waste water treatment plants, composting plants, rendering plants). In these processes, the occurrence of volatile organic sulfur compounds is mainly related to the presence of anaerobic microsites with consecutive fermentation of sulfur containing organic material and/or to the breakdown of the latter due to thermal heating. Due to the chemical complexity of these low-concentrated waste gas streams and the high flow rates to be handled, mainly biotechnological techniques and scrubbers can be used to control the odour emission. When using biofilters or trickling filters, inoculation with specific microorganisms and pH-control strategies should be implemented to optimise the removal of volatile organic sulfur compounds. In scrubbers, chemical oxidation of the volatile organic sulfur compounds can be obtained by dosing hypochlorite, ozone or hydrogen peroxide to the scrubbing liquid. However, optimal operational conditions for each of these abatement techniques requires a further research in order to guarantee a long-term and efficient overall odour abatement. PMID:10022070

  9. Impacts of simulated herbivory on volatile organic compound emission profiles from coniferous plants

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  10. Contribution of flowering trees to urban atmospheric biogenic volatile organic compound emissions

    NASA Astrophysics Data System (ADS)

    Baghi, R.; Helmig, D.; Guenther, A.; Duhl, T.; Daly, R.

    2012-04-01

    Emissions of biogenic volatile organic compounds (BVOC) from urban trees during and after blooming were measured during spring and early summer 2009 in Boulder, Colorado. Air samples were collected onto solid adsorbent cartridges from branch enclosures on the following trees: crabapple, horse chestnut, honey locust and hawthorn. These species constitute ~65% of the insect-pollinated fraction of the flowering tree canopy (excluding catkin-producing trees) from the total street area managed by the City of Boulder. Samples were subsequently analyzed for C10 - C15 BVOC by thermal desorption and gas chromatography coupled to a flame ionization detector and a mass spectrometer (GC/FID/MS). Identified emissions and emission rates from these four tree species during the flowering phase were found to vary over a wide range. Monoterpene emissions were identified for honey locust, horse chestnut and hawthorn. Sesquiterpene emissions were observed in horse chestnut and hawthorn samples. Crabapple flowers were found to emit significant amounts of benzyl alcohol and benzaldehyde. Floral BVOC emissions were found to increase with temperature, generally exhibiting exponential temperature dependence. Changes in BVOC speciation during and after the flowering period were observed for every tree studied. Emission rates were significantly higher during the blooming compared to the vegetative state for crabapple and honey locust. Total normalized (30oC) monoterpene emissions from honey locust were 4.3 fold higher during flowering (5.26 ?gC g-1h-1) than after flowering (1.23 ?gC g-1h-1). The total normalized BVOC emission rate from crabapple (93 ?gC g-1h-1) during the flowering period is of the same order as isoprene emissions from oak trees, which are among the highest BVOC emissions observed to date. These findings illustrate that during the relatively brief springtime flowering period, floral emissions constitute by far the most significant contribution to the BVOC flux from these tree species, some of which are leafless at this time. These experimental results were integrated into the MEGAN biogenic emission model and simulations were performed to estimate the contribution of floral BVOC emissions to the total urban BVOC flux during the spring flowering period. The floral BVOC emitted during this three-month simulation constitute eleven percent of the cumulative monoterpene flux for the Boulder urban area.

  11. Contribution of flowering trees to urban atmospheric biogenic volatile organic compound emissions

    NASA Astrophysics Data System (ADS)

    Baghi, R.; Helmig, D.; Guenther, A.; Duhl, T.; Daly, R.

    2012-03-01

    Emissions of biogenic volatile organic compounds (BVOC) from urban trees during and after blooming were measured during spring and early summer 2009 in Boulder, Colorado. Air samples were collected onto solid adsorbent cartridges from branch enclosures on the tree species crabapple, horse chestnut, honey locust, and hawthorn. These species constitute ~65 % of the insect-pollinated fraction of the flowering tree canopy (excluding catkin-producing trees) from the street area managed by the City of Boulder. Samples were analyzed for C10-C15 BVOC by thermal desorption and gas chromatography coupled to a flame ionization detector and a mass spectrometer (GC/FID/MS). Identified emissions and emission rates from these four tree species during the flowering phase were found to vary over a wide range. Monoterpene emissions were identified for honey locust, horse chestnut and hawthorn. Sesquiterpene emissions were observed in horse chestnut and hawthorn samples. Crabapple flowers were found to emit significant amounts of benzyl alcohol and benzaldehyde. Floral BVOC emissions increased with temperature, generally exhibiting exponential temperature dependence. Changes in BVOC speciation during and after the flowering period were observed for every tree studied. Emission rates were significantly higher during the blooming compared to the vegetative state for crabapple and honey locust. Total normalized (30 °C) monoterpene emissions from honey locust were higher during flowering (5.26 ?g Cg-1 h-1) than after flowering (1.23 ?g Cg-1 h-1). The total normalized BVOC emission rate from crabapple (93 ?g Cg-1 h-1) during the flowering period is of the same order as isoprene emissions from oak trees, which are among the highest BVOC emissions observed from plants to date. These findings illustrate that during the relatively brief springtime flowering period, floral emissions constitute by far the most significant contribution to the BVOC flux from these tree species, some of which are leafless at this time. Experimental results were integrated into the MEGAN biogenic emission model and simulations were performed to estimate the contribution of floral BVOC emissions to the total urban BVOC flux during the spring flowering period. The floral BVOC emitted during this three-month simulation are equivalent to 11 % of the cumulative monoterpene flux for the Boulder urban area.

  12. Effect of habitat and age on variations in volatile organic compound (VOC) emissions from Quercus ilex and Pinus pinea

    NASA Astrophysics Data System (ADS)

    Street, R. A.; Owen, S.; Duckham, S. C.; Boissard, C.; Hewitt, C. N.

    A dynamic branch enclosure was used to measure emission rates of volatile organic compounds (VOCs) under field conditions from two common native Mediterranean species, Quercus ilex and Pinus pinea. In addition to ?-pinene, ?-pinene, sabinene, limonene and cineole, a suite of lesser known compounds were tentatively identified including cis- and trans-ocimene, cis- and trans-linalool oxide and sabinaketone. Emissions of isoprene from Quercus ilex were insignificant in comparison to those of the monoterpenes and were not detected from Pinus pinea. Variability in emission rates between two habitats, the forest and the dunes, were assessed for Quercus ilex. Temperature sensitivities of emissions and total summed emission rates from Quercus ilex were clearly related to environmental conditions. Emission rates from Pinus pinea showed great variability, but differences between normalised mean emission rates from mature forest and young plantation trees may be significant. Existing emission rate models were found to inadequately describe the observed data.

  13. Volatile organic compound emissions from switchgrass cultivars used as biofuel crops

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    SciTech Connect

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

    1993-03-01

    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.

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

    PubMed

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

    2013-11-19

    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

  16. Investigation of carbonyl compounds in air from various industrial emission sources.

    PubMed

    Kim, Ki-Hyun; Hong, Yoon-Jung; Pal, Raktim; Jeon, Eui-Chan; Koo, Yoon-Seo; Sunwoo, Young

    2008-01-01

    The emission concentrations of carbonyl compounds in air were quantified from a total of 195 man-made source units within 77 individual companies at a large industrial complex in Korea. The measurement data were evaluated both by absolute magnitude of concentration and by their relative contribution to malodor formation such as malodor degree (MD) derived from empirical formula. It was found that formaldehyde exhibited the highest mean concentration of 323ppb with a median value of 28.2ppb, while butyraldehyde recorded the highest contribution to odor formation with an MD value of 3.5 (186 (mean) and 9.8ppb (median)). The relative intensity of carbonyl emission, when compared by the sum of MD, showed the highest source strength from the food and beverage (industry sector) and scrubber (source unit). A comprehensive evaluation of the carbonyl data from diverse industrial facilities thus allowed us to describe the fundamental patterns of their emission. PMID:17765288

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

    E-print Network

    Herndon, S. C.

    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 ...

  18. 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...

  19. Semivolatile and volatile organic compound emissions from wood-fired hydronic heaters.

    PubMed

    Aurell, Johanna; Gullett, Brian K; Tabor, Dennis; Touati, Abderrahmane; Oudejans, Lukas

    2012-07-17

    Emissions including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), polyaromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs), were sampled from different wood-fired hydronic heater (HH) technologies. Four commercially available HH technologies were studied: a single-stage conventional combustor with natural updraft, a three-stage downdraft combustion system, a bottom-fed pellet burner, and a two-stage heater with both a combustion and gasification chamber. The fuel consisted of three wood types (red oak, white pine, and white ash), one hardwood pellet brand, and one fuel mixture containing 95% red oak and 5% residential refuse by weight. The various HHs and fuel combinations were tested in a realistic homeowner fuel-charging scenario. Differences in emission levels were found between HH technologies and fuel types. PCDD/PCDF emissions ranged from 0.004 to 0.098 ng toxic equivalency/MJ(input) and PAHs from 0.49 to 54 mg/MJ(input). The former was increased by the presence of 5% by weight refuse. The white pine fuel had the highest PAH emission factor, while the bottom fed pellet burner had the lowest. The major VOCs emitted were benzene, acetylene, and propylene. The highest emissions of PAHs, VOCs, and PCDDs/PCDFs were observed with the conventional unit, likely due to the rapid changes in combustion conditions effected by the damper opening and closing. PMID:22765760

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

    NASA Astrophysics Data System (ADS)

    Kesselmeier, J.

    2012-12-01

    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.

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

    PubMed

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

    2013-07-01

    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

  2. Reduction of Volatile Organic Compounds (VOC) emission from fossil fuel combustion by catalytic treatment of flue gases

    Microsoft Academic Search

    L. Bonfanti; F. Mirabella; M. Cioni; M. Mazzanti; S. Malloggi

    Volatile Organic Compounds (VOC) emissions from industrial combustion plants can include compounds that will probably be subjected to more and more stringent regulation in the near future. Both new fuels and advanced combustion technologies used for energy generation, in spite of the advantage they can offer for increasing combustion efficiency and minimizing some conventional pollutants or relatively heavy organic micro-pollutants,

  3. Characterization of odor emission on the working face of landfill and establishing of odorous compounds index.

    PubMed

    Wenjing, Lu; Zhenhan, Duan; Dong, Li; Jimenez, Luis Miguel Caicedo; Yanjun, Liu; Hanwen, Guo; Hongtao, Wang

    2015-08-01

    Temporal variation (seasonal and daily) of odor emission on the working face of a large sanitary landfill in China was characterized through a 2 yearlong case study. Odor pollution was most serious in spring and autumn, while lower odor concentrations were detected in summer and winter. The daily fluctuation of odor concentration on the working face showed that 2:00am, 6:00am, 2:00pm and 10:00pm were the "most probable times" for odor pollution occurrence, which deserves focused attention in odor control projects. Correlations analysis found that 41% of the variance in odor concentrations can be explained by the chemical concentrations of odorous compounds. Moreover, the selection criteria for the index of odorous compounds were also established by evaluating the odor concentration, contribution to odor strength and the frequency of each compound present in all the samples. Ethyl alcohol, ?-piene, hydrogen sulfide, dimethyl sulfide, limonene, methyl mercaptan, dimethyl disulfide, and diethyl sulfide comprise the index of odorous compounds on the working face of typical municipal solid waste landfill in China. PMID:25997990

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

    NASA Astrophysics Data System (ADS)

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

    Biogenic emissions of volatile organic compounds (VOC) from forests play an important role in regulating the atmospheric trace gas composition including global tropospheric ozone concentrations. However, more information is needed on VOC emission rates from different forest regions of the world to understand regional and global impacts and to implement possible mitigation strategies. The mixed deciduous and coniferous forests of northern Wisconsin, USA, were predicted to have significant VOC emission rates because they are comprised of many genera (i.e. Picea, Populus, Quercus, Salix) known to be high VOC emitters. In July 1993, a study was conducted on the Chequamegon National Forest near Rhinelander, WI, to identify and quantify VOC emitted from major trees, shrubs, and understory herbs in the mixed northern forests of this region. Emission rates were measured at various scales - at the leaf level with cuvettes, the branch level with branch enclosures, the canopy level with a tower based system, and the landscape level with a tethered balloon air sampling system. Area-average emission rates were estimated by scaling, using biomass densities and species composition along transects representative of the study site. Isoprene (C 5H 8) was the primary VOC emitted, although significant quantities of monoterpenes (C 10H 16) were also emitted. The highest emission rates of isoprene (at 30°C and photosynthetically active radiation of 1000 ?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.

  5. Non-Methane Biogenic Volatile Organic Compound Emissions from a Subarctic Peatland Under Enhanced UV-B Radiation

    Microsoft Academic Search

    Patrick Faubert; Päivi Tiiva; A. Rinnan; J. Rasanen; Jarmo K. Holopainen; Toini Holopainen; E. Kyro; Riikka Rinnan

    2010-01-01

    Boreal and subarctic peatlands have been extensively studied for their major role in the global carbon balance. However, study efforts have so far neglected the contribution of these ecosystems to the non-methane biogenic volatile organic compound (BVOC) emissions, which are important in the atmospheric chemistry and feedbacks on climate change. We aimed at estimating the BVOC emissions from a subarctic

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

    EPA Science Inventory

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

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

    EPA Science Inventory

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

  8. Characterizing reduced sulfur compounds emissions from a swine concentrated animal feeding operation

    NASA Astrophysics Data System (ADS)

    Rumsey, Ian C.; Aneja, Viney P.; Lonneman, William A.

    2014-09-01

    Reduced sulfur compounds (RSCs) emissions from concentrated animal feeding operations (CAFOs) have become a potential environmental and human health concern, as a result of changes in livestock production methods. RSC emissions were determined from a swine CAFO in North Carolina. RSC measurements were made over a period of ?1 week from both the barn and lagoon during each of the four seasonal periods from June 2007 to April 2008. During sampling, meteorological and other environmental parameters were measured continuously. Seasonal hydrogen sulfide (H2S) barn concentrations ranged from 72 to 631 ppb. Seasonal dimethyl sulfide (DMS; CH3SCH3) and dimethyl disulfide (DMDS; CH3S2CH3) concentrations were 2-3 orders of magnitude lower, ranging from 0.18 to 0.89 ppb and 0.47 to 1.02 ppb, respectively. The overall average barn emission rate was 3.3 g day-1 AU-1 (AU (animal unit) = 500 kg of live animal weight) for H2S, which was approximately two orders of magnitude higher than the DMS and DMDS overall average emissions rates, determined as 0.017 g day-1 AU-1 and 0.036 g day-1 AU-1, respectively. The overall average lagoon flux was 1.33 ?g m-2 min-1 for H2S, which was approximately an order of magnitude higher than the overall average DMS (0.12 ?g m-2 min-1) and DMDS (0.09 ?g m-2 min-1) lagoon fluxes. The overall average lagoon emission for H2S (0.038 g day-1 AU-1) was also approximately an order of magnitude higher than the overall average DMS (0.0034 g day-1 AU-1) and DMDS (0.0028 g day-1 AU-1) emissions. H2S, DMS and DMDS have offensive odors and low odor thresholds. Over all four sampling seasons, 77% of 15 min averaged H2S barn concentrations were an order of magnitude above the average odor threshold. During these sampling periods, however, DMS and DMDS concentrations did not exceed their odor thresholds. The overall average barn and lagoon emissions from this study were used to help estimate barn, lagoon and total (barn + lagoon) RSC emissions from swine CAFOs in North Carolina. Total (barn + lagoon) H2S emissions from swine CAFOs in North Carolina were estimated to be 1.22*106 kg yr-1. The barns had significantly higher H2S emissions than the lagoons, contributing ?98% of total North Carolina H2S swine CAFO emissions. Total (barn + lagoon) emissions for DMS and DMDS were 1-2 orders of magnitude lower, with barns contributing ?86% and ?93% of total emissions, respectively. H2S swine CAFO emissions were estimated to contribute ?18% of North Carolina H2S emissions.

  9. Carbonyl compound emissions from passenger cars fueled with methanol/gasoline blends.

    PubMed

    Zhao, Hong; Ge, Yunshan; Hao, Chunxiao; Han, Xiukun; Fu, Mingliang; Yu, Linxiao; Shah, Asad Naeem

    2010-08-01

    Carbonyl compound emissions from two passenger cars fueled with different methanol/gasoline blends (M15 and M100) and operated with three-way catalytic converters (TWC) were investigated. The tests were performed on a chassis dynamometer with constant volume sampling over the New European Driving Cycle (NEDC). Carbonyls were trapped on dinitrophenylhydrazine (DNPH) cartridges. The hydrazones formed on the cartridge were analyzed by means of high-performance liquid chromatography (HPLC) and detected with a variable wavelength detector. The results show that when cars were fueled with methanol/gasoline blends, carbon monoxide (CO) and total hydrocarbon (THC) emissions decreased by 9-21% and 1-55% respectively, while nitrogen oxide (NO(x)) emissions increased by 175-233%. Compared with gasoline vehicles, formaldehyde emissions with M15 and M100 were two and four times higher respectively, and total carbonyls with M15 and M100 increased by 3% and 104% respectively. With the use of the new TWC, both regulated gas pollutants and formaldehyde decreased. The new TWC caused a decrease of 5% and 31% in formaldehyde concentration for M15 and M100, respectively. Specific reactivity (SR) with the new TWC was reduced from 5.92 to 5.72 for M15 and from 7.00 to 6.93 for M100, indicating that M15 and M100 with the new TWC were friendlier to the environment. PMID:20510438

  10. Volatile organic compound emission rate from diffused aeration systems. 1: Mass transfer modeling

    SciTech Connect

    Chern, J.M.; Yu, C.F. [Tatung Inst. of Tech., Taipei (Taiwan, Province of China). Dept. of Chemical Engineering

    1995-08-01

    The activated sludge process is one of the most commonly used biochemical oxidation process for the secondary treatment of municipal and industrial wastewaters. The release of volatile organic compounds (VOCs) from wastewater treatment plants has recently caused great concern. In wastewater treatment plants, many operation units such s equalization and aeration involve oxygen transfer between wastewater and air. While oxygen is transferred from air to wastewater, VOCs are stripped from wastewater to air. Due to increasingly stringent environmental regulations, wastewater treatment operators have to do VOC inventory of their facilities. A mass transfer model for VOCs is therefore called for to assess VOC emission rates from wastewater treatment processes. Almost all existing methods adopt an oxygen mass transfer model standardized by the American Society of Civil Engineers (ASCE) to evaluate VOC emission rates. A new and more fundamental oxygen mass transfer model for diffused aeration systems was developed to assess the VOC emission rates. The new model provides better insight of the VOC mass transfer process and requires only aeration performance data to predict the VOC emission rates. The results and implications of both models were discussed and compared.

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

    NASA Astrophysics Data System (ADS)

    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

    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%).

  12. Evaluation of high-resolution X-ray absorption and emission spectroscopy for the chemical speciation of binary titanium compounds.

    PubMed

    Reinhardt, F; Beckhoff, B; Eba, H; Kanngiesser, B; Kolbe, M; Mizusawa, M; Müller, M; Pollakowski, B; Sakurai, K; Ulm, G

    2009-03-01

    For the chemical speciation of binary compounds of tri- and tetravalent titanium, high-resolution X-ray absorption and emission spectra were recorded in different energy regimes in order to evaluate and to qualify both near-edge X-ray absorption fine structure (NEXAFS or XANES) spectroscopy and wavelength-dispersive X-ray emission spectroscopy (WDXES) as spectroscopic methods for this analytical task. A high resolving power in the excitation channel was ensured by use of monochromatic synchrotron radiation provided by BESSY II, where the soft X-ray emission spectra were recorded as well. In the hard X-ray range, emission measurements were performed at SPring-8. For a comparison of the information gained from the various methods, the titanium compounds were classified according to the bonded titanium's oxidation state. Thus, it was possible to distinguish between inner atomic effects due to different oxidation states and external effects related to the respective ligand and the surrounding structure. It becomes evident, that certain compounds, while hardly distinguishable in their Ti-K XANES spectra, still show significant differences in their emission characteristics. On the other hand, some compounds with little difference in their emission spectra are easily distinguished by their NEXAFS structures. Only the combined use of the complementary methods both in the soft and the hard X-ray range allows for a reliable speciation of tri- and tetravalent titanium compounds. PMID:19203285

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

    PubMed Central

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

    2013-01-01

    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

  14. Production of extremely low volatile organic compounds from biogenic emissions: Measured yields and atmospheric implications.

    PubMed

    Jokinen, Tuija; Berndt, Torsten; Makkonen, Risto; Kerminen, Veli-Matti; Junninen, Heikki; Paasonen, Pauli; Stratmann, Frank; Herrmann, Hartmut; Guenther, Alex B; Worsnop, Douglas R; Kulmala, Markku; Ehn, Mikael; Sipilä, Mikko

    2015-06-01

    Oxidation products of monoterpenes and isoprene have a major influence on the global secondary organic aerosol (SOA) burden and the production of atmospheric nanoparticles and cloud condensation nuclei (CCN). Here, we investigate the formation of extremely low volatility organic compounds (ELVOC) from O3 and OH radical oxidation of several monoterpenes and isoprene in a series of laboratory experiments. We show that ELVOC from all precursors are formed within the first minute after the initial attack of an oxidant. We demonstrate that under atmospherically relevant concentrations, species with an endocyclic double bond efficiently produce ELVOC from ozonolysis, whereas the yields from OH radical-initiated reactions are smaller. If the double bond is exocyclic or the compound itself is acyclic, ozonolysis produces less ELVOC and the role of the OH radical-initiated ELVOC formation is increased. Isoprene oxidation produces marginal quantities of ELVOC regardless of the oxidant. Implementing our laboratory findings into a global modeling framework shows that biogenic SOA formation in general, and ELVOC in particular, play crucial roles in atmospheric CCN production. Monoterpene oxidation products enhance atmospheric new particle formation and growth in most continental regions, thereby increasing CCN concentrations, especially at high values of cloud supersaturation. Isoprene-derived SOA tends to suppress atmospheric new particle formation, yet it assists the growth of sub-CCN-size primary particles to CCN. Taking into account compound specific monoterpene emissions has a moderate effect on the modeled global CCN budget. PMID:26015574

  15. Volatile organic compound emissions from wastewater treatment plants in Taiwan: legal regulations and costs of control.

    PubMed

    Cheng, Wen-Hsi; Hsu, Shu-Kang; Chou, Ming-Shean

    2008-09-01

    This study assessed volatile organic compound (VOC) emission characteristics from wastewater treatment plants (WWTPs) in five Taiwanese industrial districts engaged in numerous manufacturing processes, including petrochemical, science-based industry (primarily semiconductors, photo-electronics, electronic products and biological technology), as well as multiple manufacturing processes (primarily pharmaceuticals and paint manufacturing). The most aqueous hydrocarbons dissolved in the wastewater of Taiwanese WWTPs were acetone, acrylonitrile, methylene chloride, and chloroform for the petrochemical districts; acetone, chloroform, and toluene for the science-based districts; and chlorinated and aromatic hydrocarbons for the multiple industrial districts. The aqueous pollutants in the united WWTPs were closely related to the characteristics of the manufacturing plants in the districts. To effectively prevent VOC emissions from the primary treatment section of petrochemical WWTPs, the updated regulations governing VOC emissions were issued by the Taiwanese Environmental Protection Administration in September 2005, legally mandating a seal cover system incorporating venting and air purification equipment. Cost analysis indicates that incinerators with regenerative heat recovery are optimal for treating high VOC concentrations, exceeding 10,000 ppm as CH(4), from the oil separation basins. However, the emission concentrations, ranging from 100 to 1,000 ppm as CH(4) from the other primary treatment facilities and bio-treatment stages, should be collected and then injected into the biological oxidation basins via existing or new blowers. The additional capital and operating costs required to treat the VOC emissions of 1,000 ppm as CH(4) from primary treatment facilities are less than USD 0.1 for per m(3) wastewater treatment capacity. PMID:17825475

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

    SciTech Connect

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

    1994-10-01

    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.

  17. Emissions of volatile organic compounds and particulate matter from small-scale peat fires

    NASA Astrophysics Data System (ADS)

    George, I. J.; Black, R.; Walker, J. T.; Hays, M. D.; Tabor, D.; Gullett, B.

    2013-12-01

    Air pollution emitted from peat fires can negatively impact regional air quality, visibility, climate, and human health. Peat fires can smolder over long periods of time and, therefore, can release significantly greater amounts of carbon into the atmosphere per unit area compared to burning of other types of biomass. However, few studies have characterized the gas and particulate emissions from peat burning. To assess the atmospheric impact of peat fires, particulate matter (PM) and volatile organic compounds (VOCs) were quantified from controlled small-scale peat fire experiments. Major carbon emissions (i.e. CO2, CO, methane and total hydrocarbons) were measured during the peat burn experiments. Speciated PM mass was also determined from the peat burns from filter and polyurethane foam samples. Whole air samples were taken in SUMMA canisters and analyzed by gas chromatography-mass spectrometry to measure 82 trace VOCs. Additional gaseous carbonyl species were measured by sampling with dinitrophenylhydrazine-coated cartridges and analyzed with high performance liquid chromatography. VOCs with highest observed concentrations measured from the peat burns were propylene, benzene, chloromethane and toluene. Gas-phase carbonyls with highest observed concentrations included acetaldehyde, formaldehyde and acetone. Emission factors of major pollutants will be compared with recommended values for peat and other biomass burning.

  18. GLOBal Organic Emissions NETwork (GLOBOENET) tools and strategies for quantifying canopy-scale biogenic volatile organic compound emissions (Invited)

    NASA Astrophysics Data System (ADS)

    Guenther, A. B.; Duhl, T.; Karl, T.; Kim, S.; Shertz, S.; Turnipseed, A.

    2010-12-01

    The first efforts to estimate global biogenic volatile organic compound (BVOC) emissions were conducted about 50 years ago. These initial BVOC emission estimates were based solely on enclosure measurements but were soon followed in the 1970s by the first successful attempts to measure canopy-scale BVOC fluxes using micrometeorological flux measurement techniques. Above canopy flux measurements have now been applied in many different landscapes but nearly all of these studies are short term observations that are not readily available which has limited their use in model development and evaluation. This is in contrast to the community that is measuring exchanges of carbon dioxide (CO2), water vapor, and energy which has established a number of regional networks which comprise the global FLUXNET network. This network has allowed the testing of both models and satellite-derived methods of estimating surface exchanges over a variety of ecosystems and over long temporal scalesThis global network of micrometeorological tower sites also provides an opportunity to establish networks for investigating exchanges of other constituents that are exchanged between terrestrial ecosystems and the atmosphere. We have initiated a community activity, called GLOBOENET, to facilitate and coordinate efforts to measure BVOC fluxes at micrometeorological tower sites. This effort includes 1) PTRMS based eddy covariance systems that can be used to quantify fluxes of a large number of BVOC at selected locations and 2)low-cost and low-power Relaxed Eddy Accumulation (REA) systems for long-term flux measurements of a subset of BVOC at a larger number of sites. This presentation will describe the GLOBOENET tools and strategies and present some recent results. The development and application of a third generation REA system will be described along with new approaches for quantifying canopy-scale fluxes of BVOC, such as sesquiterpenes, that are difficult to measure. Results from temperate and tropical sites will be presented and a strategy for extending these observations and using them to evaluate and improve biogenic VOC emission models will be discussed.

  19. Measurement of surface emission flux rates for volatile organic compounds at Technical Area 54

    SciTech Connect

    Trujillo, V.; Morgenstern, M.; Krier, D. [Los Alamos National Lab., NM (United States); Gilkeson, R. [Weirich and Associates, Albuquerque, NM (United States)

    1998-06-01

    The survey described in this report was conducted to estimate the mass of volatile organic compounds venting to the atmosphere from active and inactive waste disposal sites at Technical Area 54. A large number of nonintrusive passive sample collection devices were placed on the ground surface for 72 hours to characterize an area of approximately 150 acres. Results provided an indication of the boundary location of the known volatile organic plume, plume constituents, and isolated high concentration areas. The data from this survey enhanced existing data from a limited number of monitor wells currently used for plume surveillance. Results indicate that the estimated mass emission to the atmosphere is orders of magnitude lower than what is considered a small flux rate at a spill site or a Resource Conservation and Recovery Act landfill and is far below the threshold limit established by the State of New Mexico as an air quality concern.

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

    SciTech Connect

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

    2004-09-01

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

  1. Laboratory measurements of emissions of nonmethane volatile organic compounds from biomass burning in Chinese crop residues

    NASA Astrophysics Data System (ADS)

    Inomata, S.; Tanimoto, H.; PAN, X.; Taketani, F.; Komazaki, Y.; Miyakawa, T.; Kanaya, Y.; Wang, Z.

    2014-12-01

    The emission factors (EFs) of volatile organic compounds (VOCs) from the burning of Chinese crop residue were investigated as a function of modified combustion efficiency by the laboratory experiments. The VOCs including acetonitrile, aldehydes/ketones, furan, and aromatic hydrocarbons were monitored by proton-transfer-reaction mass spectrometry. Two samples, wheat straw and rape plant, were burned in dry conditions and for some experiments wheat straw was burned under wet conditions. We compared the present data to the field data reported by Kudo et al. [2014]. The agreement between the field and laboratory data was obtained for aromatics for relatively more smoldering data of dry samples but the field data were slightly underestimated compared with the laboratory data for oxygenated VOCs (OVOCs) and acetonitrile. When the EFs from the burning of wet samples were investigated, the underestimations for OVOCs and acetonitrile were improved compared with the data of dry samples. It may be a property of the burning of crop residue in the region of high temperature and high humidity that some inside parts of piled crop residue and/or the crop residue facing on the ground are still wet. But the ratios for acetic acid/glycolaldehyde was still lower than 1. This may suggest that strong loss processes of acetic acid/glycolaldehyde are present in the fresh plume.Kudo S., H. Tanimoto, S. Inomata, S. Saito, X. L. Pan, Y. Kanaya, F. Taketani, Z. F. Wang, H. Chen, H. Dong, M. Zhang, and K. Yamaji (2014), Emissions of nonmethane volatile organic compounds from open crop residue burning in Yangtze River Delta region, China, J. Geophys. Res. Atmos., 119, 7684-7698, doi: 10.1002/2013JD021044.

  2. Characterization of multicapillary gas chromatography–microwave-induced plasma atomic emission spectrometry for the expeditious analysis for organometallic compounds

    Microsoft Academic Search

    Isaac Rodriguez Pereiro; Andrzej Wasik; Ryszard ?obi?ski

    1998-01-01

    Multicapillary column gas chromatography (MC-GC)–microwave-induced plasma atomic emission spectrometry (MIP-AES) is evaluated for fast speciation analysis of organometallic compounds. In situ derivatized organomercury, organotin and organolead compounds are separated isothermally within several seconds instead of several minutes required by the conventional procedures. Neither the resolution nor the sample capacity are sacrificed compared with conventional capillary GC with oven temperature gradient

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    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.

  4. Emissions from sludge incinerators with venturi and tray scrubbers and wet electrostatic precipitators: Metals, chromium and nickel compounds, and organics

    Microsoft Academic Search

    H. E. Bostian; W. G. DeWees; E. P. Crumpler; F. M. Lewis

    1993-01-01

    A comprehensive test program was developed to determine the ratios of hexavalent to total chromium and nickel subsulfide to total nickel for a typical municipal wastewater sludge incinerator under normal combustion conditions and improved combustion conditions. Emissions of metals, hexavalent chromium, nickel subsulfide, polychlorinated dibenzodioxins and furans (PCDD\\/PCDFs), semi-volatile and volatile organic compounds, carbon monoxide (CO), and total hydrocarbons (THCs)

  5. Investigation of the matrix effect in determining microimpurities in boron and its compounds by atomic-emission spectrometry

    NASA Astrophysics Data System (ADS)

    Lebedeva, R. V.; Tumanova, A. N.; Mashin, N. I.

    2007-07-01

    We carried out a systematic study of the influence of the main component on the change of analytical signal during atomic-emission analysis of boron compounds. Changes in the intensity of spectral lines of microimpurities as functions of their concentrations in the analytical system based on graphite powder with a variable content of boric acid and boron oxide are presented.

  6. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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.

  8. Determination of gaseous semi- and low-volatile organic halogen compounds by barrier-discharge atomic emission spectrometry.

    PubMed

    Sun, Yifei; Watanabe, Nobuhisa; Wang, Wei; Zhu, Tianle

    2013-01-01

    A group parameter approach using "total organic halogen" is effective for monitoring gaseous organic halogen compounds, including fluorine, chlorine, and bromine compounds, generated from combustion. We described the use of barrier-discharge radiofrequency-helium-plasma/atomic emission spectrometry, for the detection of semi- and low-volatile organic halogen compounds (SLVOXs), which can be collected by Carbotrap adsorbents and analyzed using thermal desorption. The optimal carrier gas flow rates at the injection and desorption lines were established to be 100 mL/min. The detection range for SLVOXs in the gaseous samples was from 10 ng to tens of micrograms. Measuring F was more difficult than measuring C1 or Br, because the wavelength of F is close to that of air. The barrier-discharge radiofrequency-helium-plasma/atomic emission spectrometry measured from 85% to 103% of the SLVOXs in the gas sample. It has been found that Carbotrap B is appropriate for high-boiling-point compounds, and Carbotrap C is suitable for the determination of organic halogen compounds with lower boiling points, in the range 200-2300C. Under optimal analysis conditions, a chlorine-containing plastic was destroyed using different oxygen concentrations. Lower oxygen concentrations resulted in the production of lower amounts of organic halogen compounds. PMID:23586317

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

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-08-01

    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 amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground 143 m downwind of the engines and characterized as a function of engine power from idle (4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas-phase emissions at idle, and an increasing fraction of the total gas-phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (?30%) and may be linked to cracked, partially oxidized or unburned fuel components.

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

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-03-01

    A detailed understanding of the climate and air quality impacts of aviation requires detailed measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground, 143 m downwind of the engines and characterized as a function of engine power from ground idle (~4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine-idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas phase emissions at idle, and an increasing fraction of the total gas phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (?30%) and may be linked to cracked, partially oxidized or unburned fuel components.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  12. [Emission characteristics and safety evaluation of volatile organic compounds in manufacturing processes of automotive coatings].

    PubMed

    Zeng, Pei-Yuan; Li, Jian-Jun; Liao, Dong-Qi; Tu, Xiang; Xu, Mei-Ying; Sun, Guo-Ping

    2013-12-01

    Emission characteristics of volatile organic compounds (VOCs) were investigated in an automotive coating manufacturing enterprise. Air samples were taken from eight different manufacturing areas in three workshops, and the species of VOCs and their concentrations were measured by gas chromatography-mass spectrometry (GC-MS). Safety evaluation was also conducted by comparing the concentration of VOCs with the permissible concentration-short term exposure limit (PC-STEL) regulated by the Ministry of Health. The results showed that fifteen VOCs were detected in the indoor air of the automotive coatings workshop, including benzene, toluene, ethylbenzene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, trimethylbenzene and ethylene glycol monobutyl ether, Their concentrations widely ranged from 0.51 to 593.14 mg x m(-3). The concentrations of TVOCs were significantly different among different manufacturing processes. Even in the same manufacturing process, the concentrations of each component measured at different times were also greatly different. The predominant VOCs of indoor air in the workshop were identified to be ethylbenzene and butyl acetate. The concentrations of most VOCs exceeded the occupational exposure limits, so the corresponding control measures should be taken to protect the health of the workers. PMID:24640895

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

    PubMed

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

    2014-10-01

    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

  14. A pilot system for regulatory review of process upset emissions involving toxic compounds

    SciTech Connect

    Montgomery, L.; Broberg, B.; Durrenberger, C. (Texas Air Control Board, Austin, TX (US))

    1988-01-01

    The Texas Air Control Board (TACB) receives numerous reports of process upsets that document releases of pollutants into the atmosphere. These releases represent many different compounds from a variety of release points. In order to help protect the public from adverse effects the TACB has developed a screening technique to identify cases that have the greatest potential for such efforts. This protocol uses an index (Upset Review Index (URI)) which allows upset events to be ranked by their potential adverse health and/or odor effects. The URI is a function of the emission rate and the Threshold Limit Value, odor threshold or other effect guideline. If the URI value is above the screening level, a more thorough review can be conducted which includes dispersion modeling, review of any adverse health effects and maps showing the worst-case air contaminants concentrations. This review is then used to determine if agency action should be taken to minimize the likelihood of future similar process upsets at the plant site.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  16. Cross influences of ozone and sulfate precursor emissions changes on air quality and climate

    E-print Network

    - tance of the coupling between O3 and sulfate has not been fully appreciated, and thus regulations treat), or nonmethane volatile organic compounds (NMVOCs) in the presence of nitrogen oxides (NOx). SO2 has two main under low NOx conditions as a chain termination product of the catalytic photochemical cycling

  17. Salt Lakes of Western Australia - Emissions of natural volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Sattler, Tobias; Krause, Torsten; Schöler, Heinfried; Kamilli, Katharina; Held, Andreas; Zetzsch, Cornelius; Ofner, Johannes; Junkermann, Wolfgang; Atlas, Elliot

    2013-04-01

    Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many saline lakes with a wide range of hydrogeochemical parameters. This area has been repeatedly investigated since 2006 and consists of ephemeral saline and saline groundwater sourced lakes with a pH reaching from 2.5 to 7.1. The semi-/arid region was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Today the region is mostly used for growing wheat and live stock. The deforestation led to a rising groundwater table, bringing dissolved salts and minerals to the surface. In the last decades, a concurrent alteration of rain periods has been observed. A reason could be the regional formation of ultra-fine particles that were measured with car-based and airborne instruments around the salt lakes in several campaigns between 2006 and 2011. These ultra-fine particles emitted from the lakes and acting as cloud condensation nuclei can modify cloud microphysics and thus suppress rain events [1]. New data from a campaign in 2012 accentuates the importance of these hyper saline environments for the local climate. Ground-based particle measurements around the salt lakes in 2012 were accompanied by novel chamber experiments directly on the lakes. The 1.5 m³ cubic chamber was constructed from transparent PTFE foil permitting photochemistry within while preventing dilution of the air due to lateral wind transport. This experimental setup allows linking the measured data directly to the chemistry of and above the salt lakes. Another advantage of the PTFE chamber is the enrichment of volatile organic compounds (VOC) that are emitted from salt lakes as possible precursors for the ultra-fine particles. Chamber air was sampled using stainless steel canisters. Sediment, crust and water samples were taken for investigation of potential VOC emissions in the laboratory using GC-MS technique. Different VOC and halogenated volatile compounds (VOX), exceeding atmospheric background concentrations, where identified from the sampled chamber air. Their enrichment or depletion over the time in the chamber allows for postulated reaction pathways leading to the formation of ultra-fine particles. Soil and water samples showed a variety of highly volatile and semi-volatile VOC/VOX. An abiotic formation of these VOC/VOX seems conclusive due to iron-catalysed reactions below the salt crust [2]. The salt crust is the link through which VOC/VOX pass from the soil/groundwater to the atmosphere. During desiccation salt crystals grow, trapping gases as fluid inclusions (FI). The study of FI provides qualitative emission data of VOC/VOX during desiccation which can be released upon wetting to the atmosphere. This study includes the emission of VOC/VOX from hyper saline terrestrial environments and their role in the atmospheric formation of climate relevant ultra-fine particles. [1] Junkermann et al., 2009, Atmos.Chem.Phys., 9, 6531-6539 [2] Huber et al., 2009, Environ.Sci.Technol., 43 (13), 4934-4939

  18. Emission of reactive terpene compounds from orange orchards and their removal by within-canopy processes

    Microsoft Academic Search

    Paolo Ciccioli; Enzo Brancaleoni; Massimiliano Frattoni; Vincenzo Di Palo; Riccardo Valentini; Giampiero Tirone; Guenther Seufert; Nadia Bertin; Ute Hansen; Olav Csiky; Roman Lenz; Meeta Sharma

    1999-01-01

    VOC emission from orange orchards was determined in the framework of two field campaigns aimed at assessing the contribution of vegetation emissions to tropospheric ozone formation in the Valencia Citrus belt. Branch emission from different varieties of Citrus sinensis and Citrus Clementi was dominated by beta-caryophyllene during the summer period and by linalool during the blossoming season (April-May). Large emission

  19. Biogenic volatile organic compound (BVOC) emissions from forested areas in Turkey: determination of specific emission rates for thirty-one tree species.

    PubMed

    Aydin, Yagmur Meltem; Yaman, Baris; Koca, Husnu; Dasdemir, Okan; Kara, Melik; Altiok, Hasan; Dumanoglu, Yetkin; Bayram, Abdurrahman; Tolunay, Doganay; Odabasi, Mustafa; Elbir, Tolga

    2014-08-15

    Normalized biogenic volatile organic compound (BVOC) emission rates for thirty one tree species that cover the 98% of national forested areas in Turkey were determined. Field samplings were performed at fourteen different forested areas in Turkey using a specific dynamic enclosure system. The selected branches of tree species were enclosed in a chamber consisted of a transparent Nalofan bag. The air-flows were sampled from both inlet and outlet of the chamber by Tenax-filled sorbent tubes during photosynthesis of trees under the presence of sunlight. Several environmental parameters (temperature, humidity, photosynthetically active radiation-PAR, and CO2) were continuously monitored inside and outside the enclosure chamber during the samplings. Collected samples were analyzed using a gas chromatography mass spectrometry (GC/MS) system equipped with a thermal desorber (TD). Sixty five BVOCs classified in five major groups (isoprene, monoterpenes, sesquiterpenes, oxygenated sesquiterpenes, and other oxygenated compounds) were analyzed. Emission rates were determined by normalization to standard conditions (1000 ?mol/m(2)s PAR and 30 °C temperature for isoprene and 30 °C temperature for the remaining compounds). In agreement with the literature, isoprene was mostly emitted by broad-leaved trees while coniferous species mainly emitted monoterpenes. Several tree species such as Sweet Chestnut, Silver Lime, and European Alder had higher monoterpene emissions although they are broad-leaved species. High isoprene emissions were also observed for a few coniferous species such as Nordmann Fir and Oriental Spruce. The highest normalized total BVOC emission rate of 27.1 ?g/gh was observed for Oriental Plane while South European Flowering Ash was the weakest BVOC emitter with a total normalized emission rate of 0.031 ?g/gh. Monoterpene emissions of broad-leaved species mainly consisted of sabinene, limonene and trans-beta-ocimene, while alpha-pinene, beta-pinene and beta-myrcene were generally emitted by coniferous species. Oxygenated compounds were the third most prominent BVOC group and sesquiterpenes had slightly lower contributions. PMID:24858222

  20. Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes.

    PubMed

    Liu, Huan; Luo, Guang-Qian; Hu, Hong-Yun; Zhang, Qiang; Yang, Jia-Kuan; Yao, Hong

    2012-10-15

    Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH(3)), sulfur dioxide (SO(2)), hydrogen sulfide (H(2)S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO(2) and H(2)S emissions in the H(2)SO(4) conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant release of NH(3). PMID:22902143

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

    SciTech Connect

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

    1990-08-01

    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.

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

    SciTech Connect

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

    1990-08-01

    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.

  3. The localization of hydrophilic sites within an osmium polypyridyl compound can produce a negative activation energy for emission decay

    Microsoft Academic Search

    Anula Ranatunga; Robin C. Lasey; Michael Y. Ogawa

    2001-01-01

    The temperature dependence of the emission lifetimes of two structural isomers of an osmium polypyridyl complex are reported. The compounds [Os(bpy)2(4,4?-dcbpy)] (1) and [Os(bpy)2(3,5-dcbpy)] (2), where 4,4?-dcbpy=4,4?-dicarboxy-2,2?-bipyridine and 3,5-dcbpy=3,5-dicarboxy-2,2?-bipyridine, differ only in the placement of their two hydrophilic carboxylate groups within the unique bipyridine ligand. In argon-saturated water, the emission life-time of 1 decreases with increasing temperature and can be

  4. Synchronous Scan and Excitation-Emission Matrix Fluorescence Spectroscopy of Water-Soluble Organic Compounds in Atmospheric Aerosols

    Microsoft Academic Search

    Regina M. B. O. Duarte; Casimiro A. Pio; Armando C. Duarte

    2004-01-01

    Three-dimensional excitation–emission matrix (EEM) fluorescence spectra of water-soluble organic compounds (WSOC) from aerosol samples were measured and compared with those reported in the literature for natural dissolved organic matter. The EEM profiles of the WSOC presented three characteristic excitation\\/emission (?Exc\\/?Em) peaks: 240\\/405 nm, 310\\/405 nm and 280\\/340 nm. The fluorescence intensities at ?Exc\\/?Em˜240\\/405 nm and ?Exc\\/?Em˜310\\/405 nm are located at

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2002-12-01

    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

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

    Microsoft Academic Search

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

    2006-01-01

    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

  8. Nitrogen compound emission from biomass burning in tropical African savanna FOS\\/DECAFE 1991 experiment (Lamto, Ivory Coast)

    Microsoft Academic Search

    Robert Delmas; Jean Pierre Lacaux; Jean Claude Menaut; Luc Abbadie; Xavier Roux; Gunter Helas; Jurgen Lobert

    1995-01-01

    Gaseous nitrogen compounds (NOx, NOy, NH3, N2O) were measured at ground level in smoke plumes of prescribed savanna fires in Lamto, in the southern Ivory Coast, during the FOS\\/DECAFE experiment in January 1991. During the flaming phase, the linear regression between d[NOx] and d[CO2] (differences in concentration between smoke plumes and atmosheric background) results volumic emission ratio d[NOx]\\/d[CO2]=1.37×10-3 with only

  9. The development of a sensitive method to study volatile organic compounds in gaseous emissions of lung cancer cell lines

    E-print Network

    Maroly, Anupam

    2005-08-29

    emissions in selected cancer cell lines and identification of volatile organic compounds (VOCs) in them. Disadvantages of earlier studies were that the measurements were not real time or state specific so that molecular identification was often... used to study styrene in urine and blood [37]. Techniques used Many different detection and concentration techniques apart from P&T or GC-MS have used in lung cancer studies. Each has their own advantages and disadvantages. Some of the more...

  10. Emissions of C6-C8 aromatic compounds in the United States: Constraints from tall tower and aircraft measurements

    NASA Astrophysics Data System (ADS)

    Hu, Lu; Millet, Dylan B.; Baasandorj, Munkhbayar; Griffis, Timothy J.; Travis, Katherine R.; Tessum, Christopher W.; Marshall, Julian D.; Reinhart, Wesley F.; Mikoviny, Tomas; Müller, Markus; Wisthaler, Armin; Graus, Martin; Warneke, Carsten; Gouw, Joost

    2015-01-01

    present two full years of continuous C6-C8 aromatic compound measurements by PTR-MS at the KCMP tall tower (Minnesota, US) and employ GEOS-Chem nested grid simulations in a Bayesian inversion to interpret the data in terms of new constraints on US aromatic emissions. Based on the tall tower data, we find that the RETRO inventory (year-2000) overestimates US C6-C8 aromatic emissions by factors of 2.0-4.5 during 2010-2011, likely due in part to post-2000 reductions. Likewise, our implementation of the US EPA's NEI08 overestimates the toluene flux by threefold, reflecting an inventory bias in non-road emissions plus uncertainties associated with species lumping. Our annual top-down emission estimates for benzene and C8 aromatics agree with the NEI08 bottom-up values, as does the inferred contribution from non-road sources. However, the NEI08 appears to underestimate on-road emissions of these compounds by twofold during the warm season. The implied aromatic sources upwind of North America are more than double the prior estimates, suggesting a substantial underestimate of East Asian emissions, or large increases there since 2000. Long-range transport exerts an important influence on ambient benzene over the US: on average 43% of its wintertime abundance in the US Upper Midwest is due to sources outside North America. Independent aircraft measurements show that the inventory biases found here for C6-C8 aromatics also apply to other parts of the US, with notable exceptions for toluene in California and Houston, Texas. Our best estimates of year-2011 contiguous US emissions are 206 (benzene), 408 (toluene), and 822 (C8 aromatics) GgC.

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

    E-print Network

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

    1990-01-01

    SCE has developed and implemented a research program for customer retention through VOC emission control. Following characterization of problematic emission sources, SCE has identified and evaluated a number of alternative solutions and is currently...

  12. Emissions of biogenic sulphur compounds from several wetland soils in Florida

    NASA Astrophysics Data System (ADS)

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

    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.

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

    SciTech Connect

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

    1998-06-20

    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.

  14. Biogenic Volatile Organic Compound (BVOC) emissions from agricultural crop species: is guttation a possible source for methanol emissions following light/dark transition ?

    NASA Astrophysics Data System (ADS)

    Mozaffar, Ahsan; Amelynck, Crist; Bachy, Aurélie; Digrado, Anthony; Delaplace, Pierre; du Jardin, Patrick; Fauconnier, Marie-Laure; Schoon, Niels; Aubinet, Marc; Heinesch, Bernard

    2015-04-01

    In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the atmosphere has recently been measured during an entire growing season by using the eddy covariance technique. Because of the co-variation of BVOC emission drivers in field conditions, laboratory studies were initiated in an environmental chamber in order to disentangle the responses of the emissions to variations of the individual environmental parameters (such as PPFD and temperature) and to diverse abiotic stress factors. Young plants were enclosed in transparent all-Teflon dynamic enclosures (cuvettes) through which BVOC-free and RH-controlled air was sent. BVOC enriched air was subsequently sampled from the plant cuvettes and an empty cuvette (background) and analyzed for BVOCs in a high sensitivity Proton Transfer Reaction Mass Spectrometer (hs-PTR-MS) and for CO2 in a LI-7000 non-dispersive IR gas analyzer. Emissions were monitored at constant temperature (25 °C) and at a stepwise varying PPFD pattern (0-650 µmol m-2 s-1). For maize plants, sudden light/dark transitions at the end of the photoperiod were accompanied by prompt and considerable increases in methanol (m/z 33) and water vapor (m/z 39) emissions. Moreover, guttation droplets appeared on the sides and the tips of the leaves within a few minutes after light/dark transition. Therefore the assumption has been raised that methanol is also coming out with guttation fluid from the leaves. Consequently, guttation fluid was collected from young maize and wheat plants, injected in an empty enclosure and sampled by PTR-MS. Methanol and a large number of other compounds were observed from guttation fluid. Recent studies have shown that guttation from agricultural crops frequently occurs in field conditions. Further research is required to find out the source strength of methanol emissions by this guttation phenomenon in real environmental conditions.

  15. Volatile organic compounds in the Pearl River Delta: Identification of source regions and recommendations for emission-oriented monitoring strategies

    NASA Astrophysics Data System (ADS)

    Yuan, Zibing; Zhong, Liuju; Lau, Alexis Kai Hon; Yu, Jian Zhen; Louie, Peter K. K.

    2013-09-01

    For the purpose of systematically characterizing the ambient volatile organic compound (VOC) levels and their emission sources in the Pearl River Delta (PRD) of China, a grid study with VOC samples simultaneously taken at 84 sites over the PRD was conducted in summer and winter of 2008 and 2009. Positive Matrix Factorization (PMF) model was applied to identify the major VOC contributing sources and their temporal and spatial variations. Nine sources were identified, with gasoline exhaust, industrial emission and LPG leakage & propellant emission the top three significant sources. They accounted for 23%, 16% and 13% of the ambient VOC levels, respectively. Control measures should be therefore targeted on mitigating the VOC emissions from the traffic-related and industrial-related sources. The total VOC level did not show strong increase from 5 a.m. to 10 a.m. during all the four sampling campaigns, which may result from stronger wind and higher mixing height at 10 a.m. Three hotspot areas with significant VOC contributions were identified by source apportionment analysis: (1) the Pearl River Estuary; (2) an area from Central Dongguan to North Shenzhen; and (3) the Zhuhai-Zhongshan-Jiangmen area. For better characterizing the roles of VOC and NOx in producing the secondary pollutants and to identify specific sources emitting excessive concentrations of precursors, the emission-oriented Photochemical Assessment Monitoring Station (PAMS) network is recommended to be established in the PRD. Three PAMS networks are suggested in correspondence to the three identified hotspot areas.

  16. Which emission sources are responsible for the volatile organic compounds in the atmosphere of Pearl River Delta?

    PubMed

    Guo, H; Cheng, H R; Ling, Z H; Louie, P K K; Ayoko, G A

    2011-04-15

    A field measurement study of volatile organic compounds (VOCs) was simultaneously carried out in October-December 2007 at an inland Pearl River Delta (PRD) site and a Hong Kong urban site. A receptor model i.e. positive matrix factorization (PMF) was applied to the data for the apportionment of pollution sources in the region. Five and six sources were identified in Hong Kong and the inland PRD region, respectively. The major sources identified in the region were vehicular emissions, solvent use and biomass burning, whereas extra sources found in inland PRD included liquefied petroleum gas and gasoline evaporation. In Hong Kong, the vehicular emissions made the most significant contribution to ambient VOCs (48 ± 4%), followed by solvent use (43 ± 2%) and biomass burning (9 ± 2%). In inland PRD, the largest contributor to ambient VOCs was solvent use (46 ± 1%), and vehicular emissions contributed 26 ± 1% to ambient VOCs. The percentage contribution of vehicular emission in Hong Kong in 2007 is close to that obtained in 2001-2003, whereas in inland PRD the contribution of solvent use to ambient VOCs in 2007 was at the upper range of the results obtained in previous studies and twice the 2006 PRD emission inventory. The findings advance our knowledge of ozone precursors in the PRD region. PMID:21316844

  17. Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of Chlorinated Volatile Organic Compounds

    SciTech Connect

    Jarosch, T.R.; Haselow, J.S.; Rossabi, J.; Burdick, S.A.; Raymond, R.; Young, J.E.; Lombard, K.H.

    1995-01-23

    The purpose of this report is to summarize the results of the program for off-gas treatment of atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program was funded through the Department of Energy Office of Technology Development`s VOC`s in Non-Arid Soils Integrated Demonstration (VNID). The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed (Looney et al., 1991). That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the United States to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate cost effective evaluation of the emerging technologies. Another motivation for the program is that many CVOCs will be regulated under the Clean Air Act Amendments of 1990 and are already regulated by many state regulatory programs. Additionally, compounds such as TCE and PCE are pervasive subsurface environmental contaminants, and, as a result, a small improvement in terms of abatement efficiency or cost will significantly reduce CVOC discharges to the environment as well as costs to United States government and industry.

  18. Quantifying the air pollutants emission reduction during the 2008 Olympic games in Beijing.

    PubMed

    Wang, Shuxiao; Zhao, Meng; Xing, Jia; Wu, Ye; Zhou, Yu; Lei, Yu; He, Kebin; Fu, Lixin; Hao, Jiming

    2010-04-01

    Air quality was a vital concern for the Beijing Olympic Games in 2008. To strictly control air pollutant emissions and ensure good air quality for the Games, Beijing municipal government announced an "Air Quality Guarantee Plan for the 29th Olympics in Beijing". In order to evaluate the effectiveness of the guarantee plan, this study analyzed the air pollutant emission reductions during the 29th Olympiad in Beijing. In June 2008, daily emissions of SO(2), NO(X), PM(10), and NMVOC in Beijing were 103.9 t, 428.5 t, 362.7 t, and 890.0 t, respectively. During the Olympic Games, the daily emissions of SO(2), NO(X), PM(10), and NMVOC in Beijing were reduced to 61.6 t, 229.1 t, 164.3 t, and 381.8 t -41%, 47%, 55%, and 57% lower than June 2008 emission levels. Closing facilities producing construction materials reduced the sector's SO(2) emissions by 85%. Emission control measures for mobile sources, including high-emitting vehicle restrictions, government vehicle use controls, and alternate day driving rules for Beijing's 3.3 million private cars, reduced mobile source NO(X) and NMVOC by 46% and 57%, respectively. Prohibitions on building construction reduced the sector's PM(10) emissions by approximately 90% or total PM(10) by 35%. NMVOC reductions came mainly from mobile source and fugitive emission reductions. Based on the emission inventories developed in this study, the CMAQ model was used to simulate Beijing's ambient air quality during the Olympic Games. The model results accurately reflect the environmental monitoring data providing evidence that the emission inventories in this study are reasonably accurate and quantitatively reflect the emission changes attributable to air pollution control measures taken during the 29th Olympic Games in 2008. PMID:20222727

  19. White-light emission strategy of a single organic compound with aggregation-induced emission and delayed fluorescence properties.

    PubMed

    Xie, Zongliang; Chen, Chengjian; Xu, Shidang; Li, Jun; Zhang, Yi; Liu, Siwei; Xu, Jiarui; Chi, Zhenguo

    2015-06-01

    A novel white-light-emitting organic molecule, which consists of carbazolyl- and phenothiazinyl-substituted benzophenone (OPC) and exhibits aggregation-induced emission-delayed fluorescence (AIE-DF) and mechanofluorochromic properties was synthesized. The CIE color coordinates of OPC were directly measured with a non-doped powder, which presented white-emission coordinates (0.33, 0.33) at 244?K to 252?K and (0.35, 0.35) at 298?K. The asymmetric donor-acceptor-donor' (D-A-D') type of OPC exhibits an accurate inherited relationship from dicarbazolyl-substituted benzophenone (O2C, D-A-D) and diphenothiazinyl-substituted benzophenone (O2P, D'-A-D'). By purposefully selecting the two parent molecules, that is, O2C (blue) and O2P (yellow), the white-light emission of OPC can be achieved in a single molecule. This finding provides a feasible molecular strategy to design new AIE-DF white-light-emitting organic molecules. PMID:25925015

  20. Kinetic model of C/H/N/O emissions in laser-induced breakdown spectroscopy of organic compounds

    SciTech Connect

    Dagdigian, Paul J.; Khachatrian, Ani; Babushok, Valeri I.

    2010-05-01

    A kinetic model to predict the relative intensities of the atomic C/H/N/O emission lines in laser-induced breakdown spectroscopy (LIBS) has been developed for organic compounds. The model includes a comprehensive set of chemical processes involving both neutral and ionic chemistry and physical excitation and de-excitation of atomic levels affecting the neutral, ionic, and excited-state species concentrations. The relative excited-state atom concentrations predicted by this modeling are compared with those derived from the observed LIBS intensities for 355 nm ns laser irradiation of residues of two organic compounds on aluminum substrate. The model reasonably predicts the relative excited-state concentrations, as well as their time profiles. Comparison of measured and computed concentrations has also allowed an estimation of the degree of air entrainment.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

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

    PubMed

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

    2014-09-01

    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

  3. 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 ...

  4. Significant light and temperature dependent monoterpene emissions from European beech (Fagus sylvatica L.) and their potential impact on the European volatile organic compound budget

    Microsoft Academic Search

    T. Dindorf; U. Kuhn; L. Ganzeveld; G. Schebeske; P. Ciccioli; C. Holzke; R. Köble; G. Seufert; J. Kesselmeier

    2006-01-01

    By using a dynamic branch enclosure system the emission of monoterpenes from European beech (Fagus sylvatica L.) was investigated during two consecutive summer vegetation periods in the years of 2002 and 2003 in Germany. All measurements were performed under field conditions within the framework of the ECHO project (Emission and Chemical Transformation of Biogenic Volatile Organic Compounds, AFO 2000). European

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

    NASA Astrophysics Data System (ADS)

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

    2005-10-01

    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.

  6. A genetically-based latitudinal cline in the emission of herbivore-induced plant volatile organic compounds.

    PubMed

    Wason, Elizabeth L; Agrawal, Anurag A; Hunter, Mark D

    2013-08-01

    The existence of predictable latitudinal variation in plant defense against herbivores remains controversial. A prevailing view holds that higher levels of plant defense evolve at low latitudes compared to high latitudes as an adaptive plant response to higher herbivore pressure on low-latitude plants. To date, this prediction has not been examined with respect to volatile organic compounds (VOCs) that many plants emit, often thus attracting the natural enemies of herbivores. Here, we compared genetically-based constitutive and herbivore-induced aboveground vegetative VOC emissions from plants originating across a gradient of more than 10° of latitude (>1,500 km). We collected headspace VOCs from Asclepias syriaca (common milkweed) originating from 20 populations across its natural range and grown in a common garden near the range center. Feeding by specialist Danaus plexippus (monarch) larvae induced VOCs, and field environmental conditions (temperature, light, and humidity) also influenced emissions. Monarch damage increased plant VOC concentrations and altered VOC blends. We found that genetically-based induced VOC emissions varied with the latitude of plant population origin, although the pattern followed the reverse of that predicted-induced VOC concentration increased with increasing latitude. This pattern appeared to be driven by a greater induction of sesquiterpenoids at higher latitudes. In contrast, constitutive VOC emission did not vary systematically with latitude, and the induction of green leafy volatiles declined with latitude. Our results do not support the prevailing view that plant defense is greater at lower than at higher latitudes. That the pattern holds only for herbivore-induced VOC emission, and not constitutive emission, suggests that latitudinal variation in VOCs is not a simple adaptive response to climatic factors. PMID:23888386

  7. CAIRPOL CAIRCLIP NM-VOC

    EPA Science Inventory

    The CairPol CairClip O3-NO2 is a lightweight, portable sensor for measuring ozone (O3) and nitrogen dioxide (NO2) in parts per billion (ppb) or micrograms per cubic meter (µg/m3) in applications such as personal exposure and indoor and outdoor air quality monitoring. It uses a mi...

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

    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.

  9. Tracing the link between plant volatile organic compound emissions and CO2 fluxes and by stable isotopes

    NASA Astrophysics Data System (ADS)

    Werner, Christiane; Wegener, Frederik; Jardine, Kolby

    2015-04-01

    The vegetation exerts a large influence on the atmosphere through the emission of volatile organic compounds (VOCs) and the emission and uptake of the greenhouse gas CO2. Despite the enormous importance, processes controlling plant carbon allocation into primary and secondary metabolism, such as photosynthetic carbon uptake, respiratory CO2 emission and VOC synthesis, remains unclear. Moreover, vegetation-atmosphere CO2 exchange is associated with a large isotopic imprint due to photosynthetic carbon isotope discrimination and 13C-fractionation during respiratory CO2 release1. The latter has 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 pyruvate. 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 the linkage between VOC emissions, CO2 fluxes and associated isotope effects based on simultaneous real-time measurements of stable carbon isotope composition of branch respired CO2 (CRDS) and VOC fluxes (PTR-MS). We utilized positionally specific 13C-labeled pyruvate branch feeding experiments in the mediterranean shrub (Halimium halimifolium) to trace the partitioning of C1, C2, and C3 carbon atoms of pyruvate into VOCs versus CO2 emissions in the light and in the dark. In the light, we found high emission rates of a large array of VOC including volatile isoprenoids, oxygenated VOCs, green leaf volatiles, aromatics, sulfides, and nitrogen containing VOCs. These observations suggest that in the light, H. halimifolium dedicates a high carbon flux through secondary biosynthetic pathways including the pyruvate dehydrogenase bypass, mevalonic acid, MEP/DOXP, shikimic acid, and fatty acid pathways. Moreover, we found that high VOC emissions were closely related to 13CO2 decarboxylation from pyruvate-1-13C in the light, while mitochondrial respiration mas markedly down-regulated. Moreover, we found that in the dark, VOC emissions dramatically declined while respiration was stimulated with 13CO2 emissions under pyruvate-1-13C exceeding those under pyruvate-2-13C and pyruvate-2,3-13C during light-dark transitions. Our observations suggest VOC emissions are associated with significant pyruvate C1 decarboxylation. Moreover, the data suggests that light fundamentally controls the partitioning of assimilated carbon in leaves by regulating the competition for pyruvate between secondary biosynthetic reactions (e.g. VOC production) and mitochondrial respiration. Our investigation provides novel tool to better understand the mechanistic links between primary and secondary carbon metabolism in plants with important implications for a better understanding biosphere-atmosphere exchange of CO2 and VOCs. References 1. 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 2. Jardine K, Wegener F, Abrell L, vonHaren J, Werner C (2014) Phytogenic biosynthesis and emission of methyl acetate. PCE 37, 414-424.

  10. Emission of volatile organic compounds during composting of municipal solid wastes

    Microsoft Academic Search

    Dimitris P Komilis; Robert K Ham; Jae K Park

    2004-01-01

    The objective of this study was to identify and quantify volatile and semi-volatile organic compounds (VOCs) produced during composting of the organic fraction of municipal solid wastes (MSW). A laboratory experiment was conducted using organic components of MSW that were decomposed under controlled aerobic conditions. Mixed paper primarily produced alkylated benzenes, alcohols and alkanes. Yard wastes primarily produced terpenes, alkylated

  11. Windstorm effect on forest sources of biogenic vola tile organic compound emissions in the High Tatras

    Microsoft Academic Search

    P. Fleischer

    The 19 November 2004 windstorm caused significant forest damage in the High Tatras. Windstorm effect on forest sources of biogenic vola tile organic compounds (BVOC) has been studied using BEIS2 series of GLOBEIS model for domain of square 16 km x 16 km with grid 1 km for periods from July to September in 2004 and 2005, re spectively. Differences

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

    SciTech Connect

    Stensel, H. David; Strand, Stuart E.

    2001-03-14

    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.

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

    Microsoft Academic Search

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

    1999-01-01

    Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2 - 9.5 months following installation and in seven new site- built houses 1 - 2 months after completion. The houses were in four projects located in hot- humid and mixed-humid climates. They were finished and operational, but unoccupied. Ventilation rates ranged

  14. COMPARISON OF EMISSION PROFILES FOR VOLATILE ORGANIC COMPOUNDS FROM COTTON AND POLYPROPYLENE-BASED TARP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A high electric field, radio-frequency ion mobility analyzer (RF-IMS) was used as a small detector in gas chromatographic separations of mixtures of volatile organic compounds including alcohols, aldehydes, esters, ethers, pheromes, and other chemical attractants for insects. The detector was equip...

  15. CHARACTERIZATION OF EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM INTERIOR ALKYD PAINT

    EPA Science Inventory

    Alkyd paint continues to be used indoors for application to wood trim, cabinet surfaces, and some kitchen and bathroom walls. Paint may represent a significant source of volatile organic compounds (VOCs) indoors depending on the frequency of use and amount of surface paint. The U...

  16. Emission of volatile organic compounds from two silver birch ( Betula pendula Roth) clones grown under ambient and elevated CO 2 and different O 3 concentrations

    NASA Astrophysics Data System (ADS)

    Vuorinen, Terhi; Nerg, Anne-Marja; Vapaavuori, Elina; Holopainen, Jarmo K.

    We analysed the emission of volatile organic compounds (VOCs) from two clones (4 and 80) of silver birch ( Betula pendula Roth) trees exposed to doubled ambient CO 2 and O 3 singly and in combination, in open-top chambers. VOCs were collected in July and in August from detached twigs. The effect of twig detachment as such on emissions was separately studied, and it increased the emissions of green leaf volatiles. The emission in July from both clones was dominated by sesquiterpenes (SQTs) germacrene D, ( E,E)- ?-farnesene, ?-copaene and ?-bourbonene, while in August, the emission was dominated by monoterpenes (MTs) ( E)- ?-ocimene and ( Z)-ocimene. Elevated CO 2 concentration marginally decreased total MT emission in July, while in August the total MT emission was enhanced by elevated CO 2. O 3 or CO 2+O 3-exposure did not have any effect on total MT or total SQT emissions. In general clones 4 and 80 emitted total quantified VOCs (19 compounds) 12520 and 8590 ng g -1 fw h -1 in July, and 4640 and 4990 ng g -1 fw h -1 in August, respectively. Clone 4 emitted more ?-pinene+myrcene, ( Z)-ocimene and ( E)- ?-ocimene in July than clone 80, which emitted more linalool in July, and hexanal in August than clone 4. Elevated CO 2 tended to decrease the emissions of nonanal and ( E)- ?-ocimene in July, while O 3 and CO 2+O 3 had no effects on emissions. Our results indicate that elevated CO 2 and O 3 concentrations do not have considerable effect on silver birch emissions by increasing the carbon allocation to VOCs or by inducing the emission of novel compounds. Other factors, such as temperature, light and herbivores might conceal the effects of these atmospheric gases. High SQT proportion in emission profile suggests that B. pendula may have substantial role in biogenic aerosol formation in boreal forests.

  17. Emission of volatile organic compounds as affected by feedlot location, moisture, and temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effects within pen location, moisture, and temperature on odor emission from manure resulting from a diet containing 30% wet distillers grain with solubles. Pen surface material was collected from three locations. Material from each pen was consolidated for each specific...

  18. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    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.

  20. EMISSION OF SULFUR-BEARING COMPOUNDS FROM MOTOR VEHICLE AND AIRCRAFT ENGINES. A REPORT TO CONGRESS

    EPA Science Inventory

    This report was generated in response to section 403(g) of The Clean Air Act as amended August, 1977. The report covers (1) a review of emission factors for H2SO4, SO2, sulfate, H2S, and carbonyl sulfide from motor vehicles, motor vehicle engines and aircraft engines; (2) a revie...

  1. VARIATIONS IN THE EMISSIONS OF VOLATILE ORGANIC COMPOUNDS FROM THE TONER FROM A SPECIFIC PHOTOCOPIER

    EPA Science Inventory

    A laboratory thermal desorption apparatus was used to measure emissions from a number of nominally identical photocopier toners - manufactured for use in a specific model copier - when these toners were heated to fuser temperature (180 - 200 degrees C). The objective was to deter...

  2. [Emission characteristics and hazard assessment analysis of volatile organic compounds from chemical synthesis pharmaceutical industry].

    PubMed

    Li, Yan; Wang, Zhe-Ming; Song, Shuang; Xu, Zhi-Rong; Xu, Ming-Zhu; Xu, Wei-Li

    2014-10-01

    In this study, volatile organic compounds (VOCs) released from chemical synthesis pharmaceutical industry in Taizhou, Zhejiang province were analyzed quantitatively and qualitatively. The total volatile organic compounds (TVOCs) was in the range of 14.9-308.6 mg · m(-3). Evaluation models of ozone formation potentials (OFP) and health risk assessment were adopted to preliminarily assess the environmental impact and health risk of VOCs. The results showed that the values of OFP of VOCs were in the range of 3.1-315.1 mg · m(-3), based on the maximum incremental reactivity, the main principal contribution was toluene, tetrahydrofuran (THF), acetic ether etc. The non-carcinogenic risk and the carcinogen risk fell in the ranges of 9.48 x 10(-7)-4.98 x 10(-4) a(-1) and 3.17 x 10(-5)- 6.33 x 10(-3). The principal contribution of VOCs was benzene, formaldehyde and methylene chloride. PMID:25693367

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

    SciTech Connect

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

    2012-01-01

    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.

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

    SciTech Connect

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

    2012-01-01

    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

  5. Bright white-light emission from a single organic compound in the solid state.

    PubMed

    Yang, Qing-Yuan; Lehn, Jean-Marie

    2014-04-25

    White-light-emitting materials and devices have attracted enormous interest because of their great potential for various lighting applications. We herein describe the light-emitting properties of a series of new difunctional organic molecules of remarkably simple structure consisting of two terminal 4-pyridone push-pull subunits separated by a polymethylene chain. They were found to emit almost "pure" white light as a single organic compound in the solid state, as well as when incorporated in a polymer film. To the best of our knowledge, they are the simplest white-light-emitting organic molecules reported to date. PMID:24677585

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  10. Erbium-ytterbium-yttrium compounds for light emission at 1.54microm

    NASA Astrophysics Data System (ADS)

    Vanhoutte, Michiel

    Silicon microphotonics? has emerged as the leading technology to overcome the interconnect bottleneck that limits a further increase of computation power following Moore's law. Optical interconnects between different electronic microprocessors in an electronic-photonic integrated circuit (EPIC) can provide a fast, low-loss and highbandwidth alternative to electrical interconnects, which suffer from issues such as resistive heating, RC delays and channel crosstalk at an increasing device density. A crucial device in such an electronic-photonic integrated circuit is a compact, highgain and low power optical amplifier to compensate for signal attenuation due to propagation losses and to recover signal strength after subsequent 3dB splits during fanout of the optical signal to different microprocessors. Erbium ions (Er3+) are an excellent candidate to provide amplification around .. = 1.54pm for optical telecommunications. Erbium-doped fiber amplifiers (EDFAs) have already enabled long-haul optical data. transmission through silica optical fibers, but scaling down a fiber amplifier to an on-chip erbium-doped waveguide amplifier (EDWA) brings along significant materials and device design challenges. In this thesis, erbium-ytterbium oxide (Erx Yb2-xO 3) and erbium-ytterbium-yttrium silicate (ErxYhyY 2-x-ySi2O7) compounds are investigated as novel materials systems for the development of EDWAs. The high erbium and ytterbium solubility (>1022 cm-3) and refractive index (1.71 < n < 1.92) make these materials excellent candidates for compact, low-power optical amplifiers. Erx Yb2-xO 3 and ErxYhyY2-x-ySi2O 7 thin films were deposited on SiO2 and analyzed structurally and optically. The role of ytterbium in these compounds is twofold. First, ytterbium can be used as an alternative to yttrium for dilution of the erbium concentration in order to mitigate parasitic concentration quenching effects. Second, ytterbium acts as a sensitizer for erbium during optical pumping at lambda = 980nm. Comparison of the different oxide and silicate thin films reveals that the alpha-disilicate phase is the best candidate for an EDWA gain medium pumped at lambda = 980nm. By means of rate and propagation equations, the composition of an Er xYhyY2-x-ySi2O7 gain medium was optimized for application as a 3dB EDWA. The optimal composition was found to be Er0.025Yb0.200Yb0.200Y1.775Si 2O7, which provides a 1.5dB/cm gain at only 3mW of pump power. In terms of the figure of merit 3dB gain/(device area ? pump power), this material outperforms other EDWA materials reported in literature. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs mit.edu)

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

    SciTech Connect

    Lawryk, N.J.

    1994-12-31

    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.

  12. Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

    NASA Astrophysics Data System (ADS)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

    2010-11-01

    Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

  13. Anthropogenic emissions of highly reactive volatile organic compounds in eastern Texas inferred from oversampling of satellite (OMI) measurements of HCHO columns

    NASA Astrophysics Data System (ADS)

    Zhu, Lei; Jacob, Daniel J.; Mickley, Loretta J.; Marais, Eloïse A.; Cohan, Daniel S.; Yoshida, Yasuko; Duncan, Bryan N.; González Abad, Gonzalo; Chance, Kelly V.

    2014-11-01

    Satellite observations of formaldehyde (HCHO) columns provide top-down constraints on emissions of highly reactive volatile organic compounds (HRVOCs). This approach has been used previously in the US to estimate isoprene emissions from vegetation, but application to anthropogenic emissions has been stymied by lack of a discernable HCHO signal. Here we show that temporal oversampling of HCHO data from the Ozone Monitoring Instrument (OMI) for 2005–2008 enables detection of urban and industrial plumes in eastern Texas including Houston, Port Arthur, and Dallas/Fort Worth. By spatially integrating the HCHO enhancement in the Houston plume observed by OMI we estimate an anthropogenic HCHO source of 250 ± 140 kmol h?1. This implies that anthropogenic HRVOC emissions in Houston are 4.8 ± 2.7 times higher than reported by the US Environmental Protection Agency inventory, and is consistent with field studies identifying large ethene and propene emissions from petrochemical industrial sources.

  14. Diel Variation of Biogenic Volatile Organic Compound Emissions- A field Study in the Sub, Low and High Arctic on the Effect of Temperature and Light

    PubMed Central

    Lindwall, Frida; Faubert, Patrick; Rinnan, Riikka

    2015-01-01

    Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs) may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography- mass spectrometry. Five different arctic vegetation communities were examined: high arctic heaths dominated by Salix arctica and Cassiope tetragona, low arctic heaths dominated by Salix glauca and Betula nana and a subarctic peatland dominated by the moss Warnstorfia exannulata and the sedge Eriophorum russeolum. We also addressed how climate warming affects the 24-hour emission and how the daytime emissions respond to sudden darkness. The emissions from the high arctic sites were lowest and had a strong diel variation with almost no emissions during night-time. The low arctic sites as well as the subarctic site had a more stable release of BVOCs during the 24-hour period with night-time emissions in the same range as those during the day. These results warn against overlooking the night period when considering arctic emissions. During the day, the quantity of BVOCs and the number of different compounds emitted was higher under ambient light than in darkness. The monoterpenes ?-fenchene, ? -phellandrene, 3-carene and ?-terpinene as well as isoprene were absent in dark measurements during the day. Warming by open top chambers increased the emission rates both in the high and low arctic sites, forewarning higher emissions in a future warmer climate in the Arctic. PMID:25897519

  15. Estimation of volatile compounds emission rates from the working face of a large anaerobic landfill in China using a wind tunnel system

    NASA Astrophysics Data System (ADS)

    Liu, Yanjun; Lu, Wenjing; Li, Dong; Guo, Hanwen; Caicedo, Luis; Wang, Chi; Xu, Sai; Wang, Hongtao

    2015-06-01

    Municipal solid waste landfills are one of the major sources of odor complaints. The determination of volatile compounds (VCs) emissions and their rates is a necessary prerequisite to calculate and study VCs dispersion and control. In this study a wind tunnel system has been introduced to investigate the VCs emission rates from the working face of a large anaerobic landfill in China. The VCs in gas samples were characterized by gas-chromatograph-mass-spectrometer. The emission rates of VCs increased linearly with sweeping velocity (0.1 m·s-1 to 0.5 m·s-1), and 0.28 m·s-1 was selected as the recommended practical operation sweeping velocity. The VCs emission rates on the working face at the landfill site were investigated during the course of a day. 31 chemical species divided into six chemical groups were quantified with the following emission rates: oxygenated compounds: 205.73-750.00 ?g·m-2·s-1, hydrocarbons: 61.82-220.37 ?g·m-2·s-1, aromatics: 15.55-40.11 ?g·m-2·s-1, halogenated compounds: 11.71-31.57 ?g·m-2·s-1, terpenes: 2.71-18.70 ?g·m-2·s-1, and sulfur compounds: 1.29-10.84 ?g·m-2·s-1. The highest average emission rates of VCs were found from midnight to dawn (1:00-7:00). These results provide key input parameters to users of VCs dispersion models to calculate buffer distances.

  16. Comparison of two derivatization reagents for the simultaneous determination of organolead and organomanganese compounds using solid-phase microextraction followed by gas chromatography with atomic emission detection.

    PubMed

    Peñalver, Rosa; Campillo, Natalia; Hernández-Córdoba, Manuel

    2011-12-15

    Two procedures for the simultaneous determination of organolead (tetraethyllead, triethyllead and trimethyllead) and organomanganese compounds (cyclopentadienyl manganese tricarbonyl (CMT) and methylcyclopentadienyl manganese tricarbonyl (MMT)) are studied. Both procedures involve sample preconcentration by solid-phase microextraction and capillary gas chromatography coupled to atomic emission detection, the main difference being the derivatizing agent used for the ionic alkylated lead species: sodium tetrapropylborate (NaBPr(4)) and sodium tetraphenylborate (NaBPh(4)). The parameters affecting the derivatization and preconcentration steps, chromatographic separation as well as detection of the compounds were optimized. Higher sensitivity was attained for all compounds with the method involving propylation derivatization. In this case, detection limits ranged between 0.04 and 0.1 ng L(-1), depending on the compound. Detection limits of between 0.1 and 24.5 ng L(-1) were obtained, when using phenylation derivatization. A low CMT concentration was found in one of the seawater samples analyzed. PMID:22099678

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

    PubMed

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

    2010-12-01

    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

  18. Using a biological aerated filter to treat mixed water-borne volatile organic compounds and assessing its emissions.

    PubMed

    Cheng, Wen-Hsi

    2009-01-01

    A biological aerated filter (BAF) was evaluated as a fixed-biofilm process to remove water-borne volatile organic compounds (VOCs) from a multiple layer ceramic capacitor (MLCC) manufacturing plant in southern Taiwan. The components of VOC were identified to be toluene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, bromodichloromethane and isopropanol (IPA). The full-scale BAF was constructed of two separate reactors in series, respectively, using 10- and 15-cm diameter polypropylene balls as the packing materials and a successful preliminary bench-scale experiment was performed to feasibility. Experimental results show that the BAF removed over 90% chemical oxygen demand (COD) from the influent with (1188 +/- 605) mg/L of COD. A total organic loading of 2.76 kg biochemical oxygen demand (BOD)/(m3 packing x d) was determined for the packed bed, in which the flow pattern approached that of a mixed flow. A limited VOC concentration of (0.97 +/- 0.29) ppmv (as methane) was emitted from the BAF system. Moreover, the emission rate of VOC was calculated using the proposed formula, based on an air-water mass equilibrium relationship, and compared to the simulated results obtained using the Water 9 model. Both estimation approaches of calculation and model simulation revealed that 0.1% IPA (0.0031-0.0037 kg/d) were aerated into a gaseous phase, and 30% to 40% (0.006-0.008 kg/d) of the toluene were aerated. PMID:20108681

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

  20. Mass transfer of volatile organic compounds from painting material in a standard field and laboratory emission cell

    Microsoft Academic Search

    L. Z. Zhang; J. L. Niu

    2003-01-01

    The field and laboratory emission cell (FLEC) is becoming a standard method of characterizing pollutant emissions from building materials. It is significant to use the emission profiles from FLEC to scale the emissions of building materials in real buildings. The dynamics of mass transfer in such an FLEC are the key to perform this task. In this study, the mass

  1. 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)

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

    2012-04-01

    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.

  2. The contribution of vehicular emission to the atmospheric concentrations of carbon compounds in the Metropolitan Area of Sao Paulo

    NASA Astrophysics Data System (ADS)

    Andrade, M.; Fornaro, A.; Miranda, R.; Ynoue, R. Y.; Freitas, E. D.; LAPAt-Laboratorio de Analise dos Processos Atmosfericos

    2013-05-01

    It is recognized that megacities have regional and global effects on climate, and that aerosols and Green House Gases (GHG) constitute the principal tracer of those effects. Such is the case in the Metropolitan Area of Sao Paulo (MASP), one of the largest mega-cities in the world. MASP has a population of almost 20 million inhabitants. The main source of air pollution is the transport sector. In this region, there are approximately 6.5 million passenger cars and commercial vehicles: 85% light duty, 3% heavy-duty diesel vehicles (diesel + 3% bio-diesel) and 12% motorcycles. Of the light duty vehicle, approximately 55% burn a mixture (v/v) of 78% gasoline with 22% ethanol (referred to as gasohol), 4% use hydrated ethanol (95% ethanol + 5% water), 38% flexible fuel vehicles capable of burning both gasohol as hydrated ethanol, and 2% use diesel. In average 50% of the fuel used in MASP is ethanol what brings the necessity of more studies to understand the formation of photochemical oxidants and secondary particles. According to the São Paulo State Environmental Protection Agency, 97% of carbon monoxide (CO), 85% of hydrocarbons (HC), 82% of nitrogen oxides (NOx), 36% of sulfur dioxide emitted, and 36% of all inhalable particulate matter (PM10) are emitted by the vehicular fleet. Concerning particles, 75% of the Fine Particle Concentration is related to the burning of fuel, mainly diesel. The fine particles are composed of Organic Carbon (40%), Black Carbon (30%), ions (15%) and metals. It is known that the soot is warming the climate and is important to the radiative balance. Another important driver to the radiative balance, the CO2 is mainly emitted by the transport sector, which is responsible for 57% of its emission. A comprehensive project under development has the objective of determine the role of MASP as the source of gaseous and particle compounds to the atmosphere of the region and in a mesoscale perspective. The project with funding from the São Paulo Science Foundation, called NARROWING THE UNCERTAINTIES ON AEROSOL AND CLIMATE CHANGES IN SÃO PAULO STATE - NUANCE-SPS, comprising various subprojects, employ measurements and modeling to study gaseous and particles in the atmosphere: sources; evolution in the atmosphere; formation of secondary particles; deposition; and potential impact on the climate and human health. Ground-based and vertical profile measurements are being performed (in situ, ozonesondes and LIDAR). Emission inventory is being elaborated based on the measurements of emission factors from the vehicular fleet. The formation of ozone and fine particles is being modeled with the WRF-Chem (weather and research forecast with chemistry) model. The influence of the megacity emission to the concentration of the secondary pollutants is being evaluated and correlated to health impacts.

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

    SciTech Connect

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

    2012-01-01

    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.

  4. Emissions of volatile and potentially toxic organic compounds from waste-water treatment plants and collection systems (Phase 2). Volume 1. Project summaries. Final report

    SciTech Connect

    Chang, D.P.Y.; Schroeder, E.D.; Corsi, R.L.; Guensler, R.; Meyerhofer, J.A.

    1991-08-01

    The objectives of the Phase II research project on emission of potentially toxic organic compounds (PTOCs) from wastewater treatment plants were fivefold: (1) assessment of the importance of gaseous emissions from municipal wastewater collection systems; (2) resolution of the discrepancy between the measured and estimated emissions (Phase I), from the Joint Water Pollution Control Plant (JWPCP) operated by the County Sanitation Districts of Los Angeles County (CSDLAC); (3) determination of airborne concentrations of PTOCS immediately downwind of an activated sludge aeration process at the City of Los Angeles' Hyperion Treatment Plant (HTP); (4) a modeling assessment of the effects of transient loading on emissions during preliminary and primary treatment at a typical municipal wastewater treatment plant (MWTP); (5) a preliminary investigation of effects of chlorination practices on haloform production. Volume 1, for which the abstract was prepared, contains a summary of results from each project; Volume 2 contains the discussion regarding the modeling of collection system emissions; Volume 3 addresses methods development and field sampling efforts at the JWPCP and HTP, data on emissions from a mechanically ventilated sewer and results of some preliminary haloform formation studies in wastewaters; and Volume 4 discusses aspects of the emissions modeling problem.

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

    PubMed

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

    2010-01-15

    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

  6. 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

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

    2014-09-01

    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

  7. Comparison of two derivatization reagents for the simultaneous determination of organolead and organomanganese compounds using solid-phase microextraction followed by gas chromatography with atomic emission detection

    Microsoft Academic Search

    Rosa Peñalver; Natalia Campillo; Manuel Hernández-Córdoba

    Two procedures for the simultaneous determination of organolead (tetraethyllead, triethyllead and trimethyllead) and organomanganese compounds (cyclopentadienyl manganese tricarbonyl (CMT) and methylcyclopentadienyl manganese tricarbonyl (MMT)) are studied. Both procedures involve sample preconcentration by solid-phase microextraction and capillary gas chromatography coupled to atomic emission detection, the main difference being the derivatizing agent used for the ionic alkylated lead species: sodium tetrapropylborate (NaBPr4)

  8. Biogenic Volatile Organic Compound Emissions from Vegetation and Paper Mills in the Southeast United States during the SENEX (Southeast Nexus) Campaign in 2013

    NASA Astrophysics Data System (ADS)

    Warneke, C.; Trainer, M.; Graus, M.; Yuan, B.; Holloway, J. S.; Peischl, J.; Pollack, I. B.; Ryerson, T. B.; Kaser, L.; Guenther, A. B.; De Gouw, J. A.

    2014-12-01

    Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeast of the U.S. and rival those found in tropical forests. In addition, anthropogenic emissions are significant in the Southeast and photochemistry is rapid. The NOAA SENEX aircraft campaign took place in June-July 2013 in the southeast U.S. as part of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between these emissions to form secondary pollutants. The NOAA WP-3 aircraft conducted 20 research flights between May 27 and July 10, 2013 based out of Smyrna, TN. In this presentation we focus on the emissions of biogenic volatile organic compounds (VOCs). Various methods to determine emissions of isoprene and monoterpenes are investigated, e.g.: (1) emissions are determined by looking at the ambient mixing ratio, their lifetime and mixing volume, (2) eddy covariance or wavelet flux measurement techniques are tested, and (3) using the NCAR C-130 observations of isoprene fluxes, the correlations between fluxes and concentrations and variability to estimate fluxes from the P-3 data. The resulting emission flux estimates are compared with biogenic emission inventories. The forested Southeast US is heavily managed for large-scale wood and wood products production and therefore has a large density of pulp and paper mills, which are a source of monoterpenes and other VOCs that are typically thought to be biogenic. The significance of VOC emissions from point sources such as the paper mills and others are investigated.

  9. A Genetically-Based Latitudinal Cline in the Emission of Herbivore-Induced Plant Volatile Organic Compounds

    E-print Network

    Agrawal, Anurag

    in a common garden near the range center. Feeding by specialist Danaus plexippus (monarch) larvae induced VOCs gradient . Monarch butterfly Danaus plexippus . Volatile organic compounds Introduction Geographic patterns

  10. Analysis of C 1, C 2, and C 10 through C 33 particle-phase and semi-volatile organic compound emissions from heavy-duty diesel engines

    NASA Astrophysics Data System (ADS)

    Gerald Liu, Z.; Berg, Devin R.; Vasys, Victoria N.; Dettmann, Melissa E.; Zielinska, Barbara; Schauer, James J.

    2010-03-01

    To meet increasingly stringent regulations for diesel engines, technologies such as combustion strategies, aftertreatment components, and fuel composition have continually evolved. The emissions reduction achieved by individual aftertreatment components using the same engine and fuel has been assessed and published previously ( Liu et al., 2008a,b,c). The present study instead adopted a systems approach to evaluate the net effect of the corresponding technologies for model-year 2004 and 2007 engines. The 2004 engine was equipped with an exhaust gas recirculation (EGR) system, while the 2007 engine had an EGR system, a crankcase emissions coalescer, and a diesel particulate filter. The test engines were operated under the transient federal test procedure and samples were collected with a source dilution sampling system designed to stimulate atmospheric cooling and dilution conditions. The samples were analyzed for elemental carbon, organic carbon, and C 1, C 2, and C 10 through C 33 particle-phase and semi-volatile organic compounds. Of the more than 150 organic species analyzed, the largest portion of the emissions from the 2004 engine consisted of formaldehyde, acetaldehyde, and naphthalene and its derivatives, which were significantly reduced by the 2007 engine and emissions technology. The systems approach in this study simulates the operation of real-world diesel engines, and may provide insight into the future development of integrated engine technology. The results supply updated information for assessing the impact of diesel engine emissions on the chemical processes, radiative properties, and toxic components of the atmosphere.

  11. 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)

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

    2012-03-01

    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.

  12. and Uncertainty in Stationary Natural Gas-fueled Internal Combustion Engine NOx and Total Organic Compounds Emission Factors

    Microsoft Academic Search

    H. Christopher Frey

    Quantitative methods for characterizing both variability and uncertainty are applied to case studies of emission factors for stationary natural gas-fueled internal combustion engines. NOx and Total Organic Carbon (TOC) emission data sets for lean burn engines were analyzed. Data were available for uncontrolled engines and for engines with pre-combustion chamber (PCC) and \\

  13. SEASONAL AND ANNUAL MODELING OF REDUCED NITROGEN COMPOUNDS OVER THE EASTERN UNITED STATES: EMISSIONS, AMBIENT LEVELS, AND DEPOSITION AMOUNTS

    EPA Science Inventory

    Detailed description of the distributions and seasonal trends of atmospheric nitrogen compounds is of considerable interest given their role in formation of acidic substances, tropospheric ozone and particulate matter and nutrient loading effects resulting from their deposition t...

  14. BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS (BVOCS) II. LANDSCAPE FLUX POTENTIALS FROM THREE CONTINENTAL SITES IN THE U.S.

    EPA Science Inventory

    Landscape flux potentials for biogenic volatile organic compounds (BVOCs) were derived for three ecosystems in the continental U. S. (Fernbank Forest, Atlanta, GA; Willow Creek, Rhinelander, WI; Temple Ridge, CO). Analytical data from branch enclosure measurements reported in a ...

  15. 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

    NASA Astrophysics Data System (ADS)

    Bon, D. M.; Ulbrich, I. M.; 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.; Springston, S.; Vargas, O.

    2011-03-01

    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 ~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.

  16. Measurement of fugitive volatile organic compound emissions from a petrochemical tank farm using open-path Fourier transform infrared spectrometry

    NASA Astrophysics Data System (ADS)

    Wu, Chang-Fu; Wu, Tzong-gang; Hashmonay, Ram A.; Chang, Shih-Ying; Wu, Yu-Syuan; Chao, Chun-Ping; Hsu, Cheng-Ping; Chase, Michael J.; Kagann, Robert H.

    2014-01-01

    Fugitive emission of air pollutants is conventionally estimated based on standard emission factors. The Vertical Radial Plume Mapping (VRPM) technique, as described in the US EPA OTM-10, is designed to measure emission flux by directly monitoring the concentration of the plume crossing a vertical plane downwind of the site of interest. This paper describes the evaluation results of implementing VRPM in a complex industrial setting (a petrochemical tank farm). The vertical plane was constructed from five retroreflectors and an open-path Fourier transform infrared spectrometer. The VRPM configuration was approximately 189.2 m in width × 30.7 m in height. In the accompanying tracer gas experiment, the bias of the VRPM estimate was less than 2% and its 95% confidence interval contained the true release rate. Emission estimates of the target VOCs (benzene, m-xylene, o-xylene, p-xylene, and toluene) ranged from 0.86 to 2.18 g s-1 during the 14-day field campaign, while estimates based on the standard emission factors were one order of magnitude lower, possibly leading to an underestimation of the impact of these fugitive emissions on air quality and human health. It was also demonstrated that a simplified 3-beam geometry (i.e., without one dimensional scanning lines) resulted in higher uncertainties in the emission estimates.

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

    NASA Astrophysics Data System (ADS)

    Sadavarte, Pankaj; Venkataraman, Chandra

    2014-12-01

    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.

  18. 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...

  19. 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...

  20. Headspace solid-phase microextraction for the determination of volatile organic sulphur and selenium compounds in beers, wines and spirits using gas chromatography and atomic emission detection.

    PubMed

    Campillo, Natalia; Peñalver, Rosa; López-García, Ignacio; Hernández-Córdoba, Manuel

    2009-09-25

    A rapid and solvent-free method for the determination of eight volatile organic sulphur and two selenium compounds in different beverage samples using headspace solid-phase microextraction and gas chromatography with atomic emission detection has been developed. The bonded carboxen/polydimethylsiloxane fiber was the most suitable for preconcentrating the analytes from the headspace of the sample solution. Volumes of 20 mL of undiluted beer were used while, in the case of wines and spirits, sample:water ratios of 5:15 and 2:18, respectively, were used, in order to obtain the maximum sensitivity. Quantitation was carried out by using synthetic matrices of beer and wine, and a spiked sample for spirits, and using ethyl methyl sulphide and isopropyl disulphide as internal standards. Detection limits ranged from 8 ng L(-1) to 40 ng mL(-1), depending on the compound and the beverage sample analyzed, with a fiber time exposure of 20 min at ambient temperature. The optimized method was successfully applied to different samples, some of the studied compounds being detected at concentration levels in the 0.04-152 ng mL(-1) range. PMID:19700163

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    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 the number of vehicles, annual mileage, and emission factors. We develop two scenarios for 2020: a scenario where emission factors remain the same as they were in 2000 (No-Policy, NoPol), 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 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 NoPol and Euro 3 scenarios. We evaluate the 2000 model results with observations in Japan, China, Korea, and Russia. Under NoPol 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 NoPol. 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 NoPol 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.

  3. 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...

  4. EMISSIONS FROM SLUDGE INCINERATORS WITH VENTURI AND TRAY SCRUBBERS AND WET ELECTROSTATIC PRECIPITATORS - METALS, CHROMIUM AND NICKEL COMPOUNDS, AND ORGANICS

    EPA Science Inventory

    At Site 5 (continuing a numbering system initiated in a previous 4-site project) tests were only conducted for methods development purposes. At Site 6, emissions were measured at the inlet and outlet of the control device. At Site 7, an evaluation of CO and THC CEMSs was performe...

  5. Fast online emission monitoring of volatile organic compounds (VOC) in wastewater and product streams (using stripping with direct steam injection).

    PubMed

    Schocker, Alexander; Lissner, Bert

    2012-03-01

    Open-loop stripping analysis (also referred to as dynamic headspace) is a very flexible and robust technology for online monitoring of volatile organic compounds in wastewater or coolant. However, the quality and reliability of the analytical results depend strongly on the temperature during the stripping process. Hence, the careful and constant heating of the liquid phase inside the stripping column is a critical parameter. In addition, this stripping at high temperatures extends the spectrum of traceable organics to less volatile and more polar compounds with detection limits down to the ppm-level. This paper presents a novel and promising approach for fast, efficient, and constant heating by the direct injection of process steam into the strip medium. The performance of the system is demonstrated for temperatures up to 75 °C and traces of various hydrocarbons in water (e.g., tetrahydrofuran, methanol, 1-propanol, n-butanol, ethylbenzene). PMID:22186871

  6. Developmental patterns of emission of scent compounds and related gene expression in roses of the cultivar Rosa x hybrida cv. 'Yves Piaget'.

    PubMed

    Chen, Xiaomin; Baldermann, Susanne; Cao, Shuyan; Lu, Yao; Liu, Caixia; Hirata, Hiroshi; Watanabe, Naoharu

    2015-02-01

    2-Phenylethanol (2PE) and 3,5-dimethoxytoluene (DMT) are characteristic scent compounds in specific roses such as Rosa x hybrida cv. 'Yves Piaget'. We analyzed the endogenous concentrations and emission of 2PE and DMT during the unfurling process in different floral organs, as well as changes in transcript levels of the two key genes, PAR and OOMT2. The emission of both 2PE and DMT increased during floral development to reach peaks at the fully unfurled stage. The relative transcripts of PAR and OOMT2 also increased during floral development. Whereas the maximum for OOMT2 was found at the fully unfurled stage (stage 4), similar expression levels of PAR were detected at stage 4 and the senescence stage (stage 6). The results demonstrate a positive correlation between the expression levels of PAR and OOMT2 and the emission of 2PE and DMT. In addition, endogenous volatiles and relative transcripts showed tissue- and development-specific patterns. PMID:25576838

  7. Opportunity Analysis for Recovering Energy from Industrial Waste Heat and Emissions

    SciTech Connect

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

    2006-04-01

    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.

  8. 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)

    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.

    2014-12-01

    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 photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or 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 measurable amounts of secondary organic aerosol (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 photo-oxidation products of the minor volatile organic compounds (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.

  9. Structure, transport and field-emission properties of compound nanotubes: CN x vs. BNC x ( x <0.1)

    Microsoft Academic Search

    D. Golberg; P. S. Dorozhkin; Y. Bando; Z.-C. Dong; C. C. Tang; Y. Uemura; N. Grobert; M. Reyes-Reyes; H. Terrones; M. Terrones

    2003-01-01

    .   Transport and field-emission properties of as-synthesized CNx and BNCx (x<0.1) multi-walled nanotubes were compared in detail. Individual ropes made of these nanotubes and macrofilms of those\\u000a were tested. Before measurements, the nanotubes were thoroughly characterized using high-resolution and energy-filtered electron\\u000a microscopy, electron diffraction and electron-energy-loss spectroscopy. Individual ropes composed of dozens of CNx nanotubes displayed well-defined metallic behavior and

  10. A predictive method for crude oil volatile organic compounds emission from soil: evaporation and diffusion behavior investigation of binary gas mixtures.

    PubMed

    Wang, Haijing; Fischer, Thomas; Wieprecht, Wolfgang; Möller, Detlev

    2015-05-01

    Due to their mobility and toxicity, crude oil volatile organic compounds (VOCs) are representative components for oil pipeline contaminated sites detection. Therefore, contaminated location risk assessment, with airborne light detection and ranging (LIDAR) survey, in particular, requires ground-based determinative methods for oil VOCs, the interaction between oil VOCs and soil, and information on how they diffuse from underground into atmosphere. First, we developed a method for determination of crude oil VOC binary mixtures (take n-pentane and n-hexane as examples), taking synergistic effects of VOC mixtures on polydimethylsiloxane (PDMS) solid-phase microextraction (SPME) fibers into consideration. Using this method, we further aim to extract VOCs from small volumes, for example, from soil pores, using a custom-made sampling device for nondestructive SPME fiber intrusion, and to study VOC transport through heterogeneous porous media. Second, specific surface Brunauer-Emmett-Teller (BET) analysis was conducted and used for estimation of VOC isotherm parameters in soil. Finally, two models were fitted for VOC emission prediction, and the results were compared to the experimental emission results. It was found that free diffusion mode worked well, and an empirical correction factor seems to be needed for the other model to adapt to our condition for single and binary systems. PMID:25572270

  11. Henry's law constants for paint solvents and their implications on volatile organic compound emissions from automotive painting

    SciTech Connect

    Kim, B.R.; Kalis, E.M.; DeWulf, T.; Andrews, K.M.

    2000-02-01

    This paper describes experimental results of equilibrium partitioning of several significant paint solvents and formaldehyde between air and water to quantify the potential for capturing and retaining the constituents in spraybooth scrubber water during automotive painting. The compounds studied are toluene, n-butanol, methyl ethyl ketone methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, and n-methyl-2-pyrrolidinone. A set of field data collected at a Ford Motor Company assembly plant was also analyzed to determine whether data were consistent with the equilibrium phenomenon. The primary findings include: (a) There were more than six orders of magnitude difference in the Henry's law constants among the solvents studied. A solvent with a smaller constant is less easily stripped from water. The Henry's law constants decrease in the following order: toluene and xylenes > methyl ethyl ketone > n-butanol > butyl cellosolve acetate > butyl cellosolve > formaldehyde > butyl carbitol > n-methyl-2-pyrrolidinone. (b) Field data showed accumulation of n-methyl-2-pyrrolidinone and stable concentrations of butyl carbitol, butyl cellosolve, and n-butanol in the paint-sludge pit water during a 2-month period. Stable concentrations indicate a continuous, balanced capture and stripping of the solvents. Data were consistent with measured Henry's law constants. (c) The low Henry's law constant for formaldehyde is the result of the fact that it is hydrated when dissolved in water.

  12. Estimation of vehicular emission inventories in China from 1980 to 2005

    NASA Astrophysics Data System (ADS)

    Cai, Hao; Xie, Shaodong

    Multi-year inventories of vehicular emissions at a high spatial resolution of 40 km×40 km were established in China using the GIS methodology for the period 1980-2005, based on provincial statistical data from yearbooks regarding vehicles and roads, and on the emission factors for each vehicle category in each province calculated by COPERT III program. Results showed that the emissions of CH 4, CO, CO 2, NMVOC, NO x, PM 10, and SO 2 increased from 5, 1066, 19 893, 169, 174, 26, and 16 thousand tons in 1980 to 377, 36 197, 674 629, 5911, 4539, 983, and 484 thousand tons in 2005 at an annual average rate of 19%, 15%, 15%, 15%, 14%, 16%, and 15%, respectively. Statistical analysis of vehicular emissions and GDP showed that they were well positively correlated, which revealed that increase of pollutant emissions has been accompanying the growth of GDP. Spatial distribution of pollutant emissions was rather unbalanced: over three-quarters of the total emissions concentrated in developed regions of China's southeastern, northern and central areas covering only 35.2% of China's territory, while the remaining emissions were distributed over the southwestern, northwestern and northeastern regions covering as much as 64.8% of the territory. In 2005, the Beijing-Tianjin-Hebei region, the Yangtze River Delta, and the Pearl River Delta covering only 2.3%, 2.2%, and 1.9%, respectively, of the territory, generated about 10%, 19%, and 12%, respectively, of the total emissions. Since 1990, motorcycles have been the major contributors to the CH 4, CO, NMVOC, and PM 10 emissions, due to the large population. Heavy-duty vans were the major contributors to the NO x and SO 2 emissions because of high emission factors. Passenger cars contributed about one third of the emissions of each pollutant. Contributions of vehicle categories to emissions varied from province to province, due to the diversity of vehicle compositions among provinces.

  13. 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)

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

    2012-12-01

    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.

  14. An inventory of gaseous and primary aerosol emissions in Asia in the year 2000

    NASA Astrophysics Data System (ADS)

    Streets, D. G.; Bond, T. C.; Carmichael, G. R.; Fernandes, S. D.; Fu, Q.; He, D.; Klimont, Z.; Nelson, S. M.; Tsai, N. Y.; Wang, M. Q.; Woo, J.-H.; Yarber, K. F.

    2003-11-01

    An inventory of air pollutant emissions in Asia in the year 2000 is developed to support atmospheric modeling and analysis of observations taken during the TRACE-P experiment funded by the National Aeronautics and Space Administration (NASA) and the ACE-Asia experiment funded by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA). Emissions are estimated for all major anthropogenic sources, including biomass burning, in 64 regions of Asia. We estimate total Asian emissions as follows: 34.3 Tg SO2, 26.8 Tg NOx, 9870 Tg CO2, 279 Tg CO, 107 Tg CH4, 52.2 Tg NMVOC, 2.54 Tg black carbon (BC), 10.4 Tg organic carbon (OC), and 27.5 Tg NH3. In addition, NMVOC are speciated into 19 subcategories according to functional groups and reactivity. Thus we are able to identify the major source regions and types for many of the significant gaseous and particle emissions that influence pollutant concentrations in the vicinity of the TRACE-P and ACE-Asia field measurements. Emissions in China dominate the signature of pollutant concentrations in this region, so special emphasis has been placed on the development of emission estimates for China. China's emissions are determined to be as follows: 20.4 Tg SO2, 11.4 Tg NOx, 3820 Tg CO2, 116 Tg CO, 38.4 Tg CH4, 17.4 Tg NMVOC, 1.05 Tg BC, 3.4 Tg OC, and 13.6 Tg NH3. Emissions are gridded at a variety of spatial resolutions from 1° × 1° to 30 s × 30 s, using the exact locations of large point sources and surrogate GIS distributions of urban and rural population, road networks, landcover, ship lanes, etc. The gridded emission estimates have been used as inputs to atmospheric simulation models and have proven to be generally robust in comparison with field observations, though there is reason to think that emissions of CO and possibly BC may be underestimated. Monthly emission estimates for China are developed for each species to aid TRACE-P and ACE-Asia data interpretation. During the observation period of March/April, emissions are roughly at their average values (one twelfth of annual). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of ±16% for SO2 to a high of ±450% for OC.

  15. Primary emissions and secondary formation of volatile organic compounds from natural gas production in five major U.S. shale plays

    NASA Astrophysics Data System (ADS)

    Gilman, J.; Lerner, B. M.; Warneke, C.; Graus, M.; Lui, R.; Koss, A.; Yuan, B.; Murphy, S. M.; Alvarez, S. L.; Lefer, B. L.; Min, K. E.; Brown, S. S.; Roberts, J. M.; Osthoff, H. D.; Hatch, C. D.; Peischl, J.; Ryerson, T. B.; De Gouw, J. A.

    2014-12-01

    According to the U.S. Energy and Information Administration (EIA), domestic production of natural gas from shale formations is currently at the highest levels in U.S. history. Shale gas production may also result in the production of natural gas plant liquids (NGPLs) such as ethane and propane as well as natural gas condensate composed of a complex mixture of non-methane hydrocarbons containing more than ~5 carbon atoms (e.g., hexane, cyclohexane, and benzene). The amounts of natural gas liquids and condensate produced depends on the particular reservoir. The source signature of primary emissions of hydrocarbons to the atmosphere within each shale play will therefore depend on the composition of the raw natural gas as well as the industrial processes and equipment used to extract, separate, store, and transport the raw materials. Characterizing the primary emissions of VOCs from natural gas production is critical to assessing the local and regional atmospheric impacts such as the photochemical formation of ozone and secondary formation of organic aerosol. This study utilizes ground-based measurements of a full suite of volatile organic compounds (VOCs) in two western U.S. basins, the Uintah (2012-2014 winter measurements only) and Denver-Julesburg (winter 2011 and summer 2012), and airborne measurements over the Haynesville, Fayetteville, and Marcellus shale basins (summer 2013). By comparing the observed VOC to propane enhancement ratios, we show that each basin has a unique VOC source signature associated with oil and natural gas operations. Of the shale basins studied, the Uintah basin had the largest overall VOC to propane enhancement ratios while the Marcellus had the lowest. For the western basins, we will compare the composition of oxygenated VOCs produced from photochemical oxidation of VOC precursors and contrast the oxygenated VOC mixture to a "typical" summertime urban VOC mixture. The relative roles of alkanes, alkenes, aromatics, and cycloalkanes as precursors for C2-C6 aldehydes and ketones, and C3-C4 alkyl nitrates will be investigated.

  16. Evaluation of the stability of a mixture of volatile organic compounds on sorbents for the determination of emissions from indoor materials and products using thermal desorption/gas chromatography/mass spectrometry.

    PubMed

    Brown, Veronica M; Crump, Derrick R; Plant, Neil T; Pengelly, Ian

    2014-07-11

    The standard method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air (ISO 16000-6:2011) specifies sampling onto the sorbent Tenax TA followed by analysis using thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). The informative Annex D to the standard suggests the use of multi-sorbent samplers to extend the volatility range of compounds which can be determined. The aim of this study was to investigate the storage performance of Tenax TA and two multi-sorbent tubes loaded with a mixture of nine VOCs of relevance for material emissions testing. The sorbent combinations tested were quartz wool/Tenax TA/Carbograph™ 5TD and quartz wool/Tenax TA/Carbopack™ X. A range of loading levels, loading conditions (humidities and air volume), storage times (1-4 weeks) and storage conditions (refrigerated and ambient) were investigated. Longer term storage trials (up to 1 year) were conducted with Tenax TA tubes to evaluate the stability of tubes used for proficiency testing (PT) of material emissions analyses. The storage performance of the multi-sorbent tubes tested was found to be equal to that for Tenax TA, with recoveries after 4 weeks storage of within about 10% of the amounts loaded. No consistent differences in recoveries were found for the different loading or storage conditions. The longer term storage trials also showed good recovery for these compounds, although two other compounds, hexanal and BHT, were found to be unstable when stored on Tenax TA. The results of this study provide confidence in the stability of nine analytes for up to 4 weeks on two multi-sorbent tubes for material emissions testing and the same compounds loaded on Tenax TA sorbent for a recently introduced PT scheme for material emissions testing. PMID:24877978

  17. An improved system for modelling Spanish emissions: HERMESv2.0

    NASA Astrophysics Data System (ADS)

    Guevara, Marc; Martínez, Francesc; Arévalo, Gustavo; Gassó, Santiago; Baldasano, José M.

    2013-12-01

    Emission models play a key role in the development of high-resolution air quality modelling systems (AQMS). To minimise the uncertainty presented by these models, it is essential to match the high-resolution requirements of chemical transport models (CTMs) and to use up-to-date information and emission methodologies. During 2005 and 2006, the Barcelona Supercomputing Center - Centro Nacional de Supercomputación (BSC-CNS) developed the High-Elective Resolution Modelling Emissions System (HERMES04), which is a model that estimates anthropogenic and biogenic emissions for Spain with a temporal and spatial resolution of 1 h and 1 km2, taking 2004 as the reference period. Due to both the changes in Spanish emissions patterns and the age of the activity data and methodologies used, it has become necessary to update and improve the whole system. Hence, a new high-resolution emission model for Spain (HERMESv2.0) has been developed. This work introduces the improved emission estimation methodologies and data on which the model is based, as well as an analysis of the results obtained. The annual emissions estimated by HERMESv2.0 for Spain in 2009 are: NOx, 924 kt; NMVOCs, 2331 kt; SO2, 278 kt; CO, 2178 kt; NH3, 339 kt; PM10, 139 kt; and PM2.5, 105 kt. Compared with HERMES04, major differences are found in NMVOCs (+1172 kt) and SO2 (-870 kt). Important changes in emission patterns are also observed in terms of spatial and temporal distributions. A numerical comparison of both models with the Spanish National Emission Inventory indicates that previous underestimations have been heavily reduced in HERMESv2.0, especially for NOx (from -669 kt·year-1 to -176 kt·year-1), CO (from -761 kt·year-1 to 271 kt·year-1) and NMVOCs (from -1217 kt·year-1 to 135 kt·year-1). The new model substitutes HERMES04 as the emission core of the operational air quality forecasting system for Spain CALIOPE.

  18. Emission profile of 18 carbonyl compounds, CO, CO 2, and NO x emitted by a diesel engine fuelled with diesel and ternary blends containing diesel, ethanol and biodiesel or vegetable oils

    NASA Astrophysics Data System (ADS)

    Guarieiro, Lílian Lefol Nani; de Souza, Amanda Figueiredo; Torres, Ednildo Andrade; de Andrade, Jailson B.

    The impact of vehicular emissions on air depends, among other factors, on the composition of fuel and the technology used to build the engines. The reduction of vehicular emissions requires changes in the fuel composition, and improving the technologies used in the manufacturing of engines and for the after-treatment of gases. In general, improvements to diesel engines have targeted not only emission reductions, but also reductions in fuel consumption. However, changes in the fuel composition have been shown to be a more rapid and effective alternative to reduce pollution. Some factors should been taken into consideration when searching for an alternative fuel to be used in diesel engines, such as emissions, fuel stability, availability and its distribution, as well as its effects on the engine durability. In this work, 45 fuel blends were prepared and their stability was evaluated. The following mixtures (v/v/v) were stable for the 90-day period and were used in the emission study: diesel/ethanol - 90/10%, diesel/ethanol/soybean biodiesel - 80/15/5%, diesel/ethanol/castor biodiesel - 80/15/5%, diesel/ethanol/residual biodiesel - 80/15/5%, diesel/ethanol/soybean oil - 90/7/3%, and diesel/ethanol/castor oil - 90/7/3%. The diesel/ethanol fuel showed higher reduction of NO x emission at a lower load (2 kW) when compared with pure diesel. The other fuels showed a decrease of NO x emissions in the ranges of 6.9-75% and 4-85% at 1800 rpm and 2000 rpm, respectively. The combustion efficiencies of the diesel can be enhanced by the addition of the oxygenate fuels, like ethanol and biodiesel/vegetable oil, resulting in a more complete combustion in terms of NO x emission. In the case of CO 2 the decreases were in the ranges of 5-24% and 4-6% at 1800 rpm and 2000 rpm, respectively. Meanwhile, no differences were observed in CO emission. The carbonyl compounds (CC) studied were formaldehyde, acetaldehyde, propionaldehyde, acrolein, acetone, crotonaldehyde, butyraldehyde, butanone, benzaldehyde, isovaleraldehyde, valeraldehyde, o-toluenaldehyde, m-toluenaldehyde, p-toluenaldehyde, hexaldehyde, octaldehyde, 2,5-dimethylbenzaldehyde, and decaldehyde. Among them, formaldehyde, acetaldehyde, acetone, and propionaldehyde showed the highest emission concentrations. When ternary blend contains vegetable oil, there is a strong tendency to increase the emissions of the high weight CC and decrease the emissions of the low weight CC. The highest concentration of acrolein was observed when the fuel contains diesel, ethanol and biodiesel. With the exception of NO x, the use of ternary blended fuels resulted on the increase in the emission rates of the studied compounds.

  19. Determination of butyl- and phenyltin compounds in human urine by HS-SPME after derivatization with tetraethylborate and subsequent determination by capillary GC with microwave-induced plasma atomic emission and mass spectrometric detection.

    PubMed

    Zachariadis, G A; Rosenberg, E

    2009-04-30

    A headspace solid-phase micro-extraction (HS-SPME) method was developed and optimized for gas chromatographic separation and determination of commonly found organotin compounds in human urine after potential exposure. Butyl- and phenyltin compounds were in situ derivatized to ethylated derivatives by sodium tetraethylborate (NaBEt(4)) directly in the urine matrix. The relevant parameters affecting the yield of the SPME procedure were examined using tetrabutyltin as internal standard. The method was optimized for direct use in the analysis of undiluted human urine samples and mono-, di- and tri-substituted butyl- and phenyltin compounds could be determined after a 15-min headspace extraction time at room temperature. The selectivity of the microwave-induced plasma atomic emission detector (MIP-AED) as an element specific detector in combination with the relatively selective sample preparation technique of HS-SPME allowed the interference-free detection of the organotin compounds in all cases. A quadrupole mass spectrometer was used in parallel experiments as a detector for the confirmation of the identity molecular structure of the eluted compounds. The performance characteristics of the developed method are given for the determination of mixtures of these compounds. Finally the proposed method was applied to the analysis of several human urine samples. PMID:19203626

  20. EMISSION, FATE, AND CONTRIBUTION OF BIOGENIC VOLATILE ORGANIC COMPOUNDS TO ORGANIC AEROSOL FORMATION IN THE PRESENCE OF ANTHROPOGENIC POLLUTION: MEASUREMENTS AND MODELING DURING SOAS

    EPA Science Inventory

    The primary deliverable products will be measurements of VOC emission and deposition on spatial and temporal scales that are optimal for evaluating and improving regional models. Outcomes will include approaches for quantifying VOC emission uncertainties and identifying missing V...

  1. Derived Emission Rates and Photochemical Production Rates of Volatile Organic Compounds (VOCs) Associated with Oil and Natural Gas Operations in the Uintah Basin, UT During a Wintertime Ozone Formation Event

    NASA Astrophysics Data System (ADS)

    Koss, A.; De Gouw, J. A.; Warneke, C.; Gilman, J.; Lerner, B. M.; Graus, M.; Yuan, B.; Edwards, P. M.; Brown, S. S.; Wild, R. J.; Roberts, J. M.; Bates, T. S.; Quinn, P.

    2014-12-01

    The Uintah Basin, an oil and natural gas extraction field in Utah, experienced extremely high levels of volatile organic compounds (VOCs) and ozone during the winter of 2013 - up to 100 ppmv carbon and 150 ppbv O3. Here we interpret VOCs measured during an ozone formation event from 31 Jan 2013 to 8 Feb 2013. Ratios of VOCs show strong diurnal cycles and week-long trends. A simple analysis was applied to ratios of aromatic VOCs measured by proton transfer reaction mass spectrometer (PTR-MS) to explain these trends and to estimate emission rates of aromatic VOCs from oil and natural gas extraction, VOC emission ratios relative to benzene, and ambient [OH]. The analysis incorporates the following assumptions: (1) the source composition of emitted VOCs and their emission rates were temporally and spatially constant, and (2) the removal of VOCs was governed by reaction with OH, diurnal profile of which is constrained by measured photolysis rates. The main findings are (1) the emission rate of methane, extrapolated from the emission rate of benzene, is on the same order as an independent estimate from aircraft measurements of methane in 2012, (2) the derived aromatic emission ratios are consistent with source contributions from both oil and gas producing wells, and (3) calculated daily OH concentrations are low, peaking at 1x106 molecules cm-3. The analysis was extended to investigate secondary production of oxygenated VOCs measured by PTR-MS. The analysis is able to explain daytime production, but it does not adequately explain nighttime behavior, which may be affected by complex deposition to snow and ice surfaces. The relative carbon mass of primary and secondary compounds was calculated and compared to observations. At the end of the ozone formation event (day 6), our analysis predicts that secondary (oxidized) VOCs should comprise about 40% of total carbon mass. However, only 12% of these compounds are accounted for by measured oxygenated VOCs and organic aerosol. Additionally, formation rates of measured oxygenated VOCs did not sum to the total primary compound oxidation rate. The disparity is likely due to both incomplete measurements of oxygenated products and VOC loss to deposition.

  2. Emission and profile characteristic of volatile organic compounds emitted from coke production, iron smelt, heating station and power plant in Liaoning Province, China.

    PubMed

    Shi, Jianwu; Deng, Hao; Bai, Zhipeng; Kong, Shaofei; Wang, Xiuyan; Hao, Jiming; Han, Xinyu; Ning, Ping

    2015-05-15

    107 kinds of C?-C?? volatile organic compound (VOC) mass concentrations and profiles for four types of coal-fired stationary sources in Liaoning Province were studied by a dilution sampling system and GC-MS analysis method, which are of significant importance with regard to VOC emissions in northeast of China. The results showed that there were some differences among these VOC source profiles. The total mass concentrations of analyzed 107 VOC species varied from 10,917 to 19,652 ?g m(-3). Halogenated hydrocarbons exhibited higher mass percentages for the VOC source profiles of iron smelt (48.8%) and coke production plant (37.7%). Aromatic hydrocarbons were the most abundant in heating station plant (69.1%). Ketones, alcohols and acetates held 45.0% of total VOCs in thermal power plant. For non-methane hydrocarbons (NMHCs), which are demanded for photochemical assessment in the USA, toluene and n-hexane were the most abundant species in the iron smelt, coke production and thermal power plant, with the mass percentages of 64.8%, 52.7% and 38.6%, respectively. Trimethylbenzene, n-propylbenzene and o,m-ethyltoluene approximately accounted for 70.0% in heating station plant. NMHCs emitted from coke production, iron smelt, heating station and power plant listed above presented different chemical reactivities. The average OH loss rate of NMHCs from heating station, was 4 to 5.6 times higher than that of NMHCs from iron smelt, coke production and power plant, which implies that VOCs emitted from heating station in northeast of China should be controlled firstly to avoid photochemical ozone pollution and protect human health. There are significant variations in the ratios of benzene/toluene and m, p-xylene/ethylbenzene of these coal-fired source profiles. The representativeness of the coal-fired sources studied and the VOC samples collected should be more closely examined. The accuracy of VOC source profiles related to coal-fired processes is highly dependent on location and sampling method. PMID:25704266

  3. Interlaboratory evaluation of an off-line supercritical fluid extraction and gas chromatography with atomic emission detection method for the determination of organotin compounds in soil and sediments

    Microsoft Academic Search

    V. Lopez-Avila; Y. Liu; W. F. Beckert

    1997-01-01

    A collaborative study was conducted, with eight laboratories participating, to determine the method accuracy and precision of an off-line supercritical fluid extraction (SFE) method for organotin compounds. This method involves extraction of organotin compounds from solid matrixes with supercritical carbon dioxide, modified with 5% methanol, at 450 atm and 60°C for 20 min in the static mode followed by 30

  4. Uncertainty assessment of potential biogenic volatile organic compound emissions from forests with the Monte Carlo method: Case study for an episode from 1 to 10 July 2000 in Poland

    NASA Astrophysics Data System (ADS)

    Smiatek, G.; Bogacki, M.

    2005-12-01

    An uncertainty assessment of a volatile organic compounds (VOCs) emission inventory using a Monte Carlo study according to the "Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories" has been performed. For the episode of 1-10 July 2000 hourly biogenic VOC (BVOC) emissions from forests in Poland were calculated in 10 km × 10 km resolution with a semiempirical BVOC model (seBVOC). Driving parameters of the model were land cover, temperature, light intensity, foliar biomass, leaf area index (LAI), and plant-specific emission factors. The hourly meteorology input has been modeled with the nonhydrostatic Multiscale Climate Chemistry Model (MCCM). For each of the driving parameters, probability distribution functions (PDFs) based on the normal and log-normal distributions have been identified. Repeated runs of the seBVOC model in the Monte Carlo study with random figures drawn from the probability distribution functions yield the error distribution and the uncertainties. The results show an uncertainty in isoprene emission of the entire modeled period and modeling domain in the range from -71% to 73%, in monoterpene emissions in the range of -57% to 140%, and in other VOC (OVOC) emissions in the range of -55% to 57%. Uncertainties in daily estimates for the domain were higher ranging between -84% and 98% for isoprene, -63% and 147% for monoterpenes, and 63% and 72% for other VOCs. Largest uncertainty results from errors of the emission factors followed by errors in temperature and foliar biomass. These uncertainties cover only a subset of possible variables and are less than the total uncertainty.

  5. 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...

  6. Effect of mechanical damage on emission of volatile organic compounds from plant leaves and implications for evaluation of host plant specificity of prospective biological control agents of weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assessment of host plant specificity is a critical step in the evaluation of classical biological control agents of weeds, which is necessary for avoiding possible damage to nontarget plants. Volatile organic compounds (VOC) emitted by plants likely play an important role in determining which plant...

  7. Standardization of flux chamber and wind tunnel flux measurements for quantifying volatile organic compound and ammonia emissions from area sources at animal feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variety of wind tunnels and flux chambers have been used to measure fluxes of volatile organic compounds (VOC) and ammonia (NH3) at animal feeding operations (AFO). However, there has been little regard to the extreme variation and potential inaccuracies caused by inappropriate air velocity or sw...

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

    E-print Network

    Shalish, Ilan

    Role of Planar Defects in Compound Semiconductor Crystals: From Growth of Nanomasts & Nanosails of the crystal during growth [2] as well as play a role in optical and electrical properties. Future nanowires}-type surfaces provide lower energy. Thus during expansion of the crystal (normal to growth axis) one

  9. CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 4. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-2

    EPA Science Inventory

    Radian Corporation is conducting a testing program for the U.S. Environmental Protection Agency to evaluate the performance of catalytic incinerators that are applied to industrial processes for volatile organic compound (VOC) control. This report documents the results of the per...

  10. CONTINUOUS EMISSION MONITORING DEMONSTRATION PROGRAM

    EPA Science Inventory

    Continuous emissions monitoring of hazardous and mixed waste thermal treatment processes is desired for verification of emission compliance, process control, and public safety perception. pecies of particular interest include trace metals and organic compounds resulting from inco...

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

    EPA Science Inventory

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

  12. 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)

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

    2012-04-01

    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.

  13. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R. (Idaho Falls, ID); Peterson, Eric S. (Idaho Falls, ID); Wertsching, Alan K. (Idaho Falls, ID); Orme, Christopher J. (Shelley, ID); Luther, Thomas A. (Idaho Falls, ID); Jones, Michael G. (Pocatello, ID)

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  14. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R. (Idaho Falls, ID); Peterson, Eric S. (Idaho Falls, ID); Orme, Christopher J. (Shelley, ID); Jones, Michael G. (Chubbuck, ID); Wertsching, Alan K. (Idaho Falls, ID); Luther, Thomas A. (Idaho Falls, ID); Trowbridge, Tammy L. (Idaho Falls, ID)

    2011-11-22

    A PBI compound includes imidazole nitrogens at least a portion of which are substituted with a moiety containing a carbonyl group, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. At least 85% of the nitrogens may be substituted. The carbonyl-containing moiety may include RCO--, where R is alkoxy or haloalkyl. The PBI compound may exhibit a first temperature marking an onset of weight loss corresponding to reversion of the substituted PBI that is less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may use more than 5 equivalents in relation to the imidazole nitrogens to be substituted.

  15. 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

    Zachariadis, George A; Rosenberg, Erwin

    2012-05-01

    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

  16. Vanadium compounds

    Microsoft Academic Search

    Ana M. Cortizo; Viviana C. Salice; Susana B. Etcheverry

    1994-01-01

    The direct effect of different vanadium compounds upon alkaline phosphatase (ALP) activity was investigated. Vanadate and\\u000a vanadyl inhibited both the soluble and particulate ALP activity from UMR.106 cells and from bovine intestinal ALP. We have\\u000a also shown the inhibition of ALP activity in the soluble fraction of osteoblasts by peroxo and hydroperoxo vanadium compounds.\\u000a ALP activity in the particulate fraction

  17. Method of removal of volatile organic compounds by using wet scrubber coupled with photo-Fenton reaction--preventing emission of by-products.

    PubMed

    Tokumura, Masahiro; Wada, Yuko; Usami, Yuri; Yamaki, Takako; Mizukoshi, Atsushi; Noguchi, Miyuki; Yanagisawa, Yukio

    2012-11-01

    The photo-Fenton reaction was applied as a novel method for the removal of volatile organic compounds (VOCs) in the gas phase, and its effectiveness was experimentally examined. In conventional VOCs removal methods using a photocatalyst or ozone, VOCs are oxidized in the gas phase. Therefore, incompletely oxidized intermediates, which may have adverse effects on health, are likely to contaminate the treated air. On the other hand, in the VOCs removal method developed in this study, because the VOCs are oxidized in the liquid phase by the photo-Fenton reaction, any incompletely oxidized intermediates produced are confined to the liquid phase. As a result, the contamination of the treated air by these harmful intermediates can be prevented. Using a semi-batch process, it was found that the removal efficiency for toluene in a one-pass test (residence time of 17s) was 61%, for an inlet toluene gas concentration of 930 ppbv, an initial iron ion concentration of 20 mg L(-1), and an initial hydrogen peroxide concentration of 630 mg L(-1). The removal efficiency was almost constant as long as H(2)O(2) was present in the solution. Proton transfer reaction mass spectrometry analysis confirmed the absence of any incompletely oxidized intermediates in the treated air. PMID:22871338

  18. Atmos. Chem. Phys., 10, 1196911985, 2010 www.atmos-chem-phys.net/10/11969/2010/

    E-print Network

    Meskhidze, Nicholas

    using a newly-developed ship-plume photochemi- cal/dynamic model: (1) primary HCHO emission from ships compounds (NMVOCs) emitted from ships; and (3) atmospheric oxidation of CH4 within the ship plumes. For this ship-plume modelling study, the ITCT 2K2 (Intercontinental Transport and Chemi- cal Transformation 2002

  19. A predictive method for volatile organic compounds emission from soil: Evaporation and diffusion behavior investigation of a representative component of crude oil.

    PubMed

    Wang, Haijing; Fischer, Thomas; Wieprecht, Wolfgang; Möller, Detlev

    2015-10-15

    Pipelines are convenient, economical and widely used mode of transportation of crude oil. However, the inevitable or otherwise accidents during such transport of crude oil lead to large scale oil spills, which consequently result in both soil and air pollution. When such pollution occurs, crude oil VOC concentrations in air, soil pollution evaluation and VOC propagation in soil provide important evidence for airborne detection of oils spills. Therefore, several issues, including determination method for VOC, isotherm parameters of VOC sorption on soil surfaces, and VOC diffusion flux simulation, are significant. In our previous study, n-butane and n-pentane were proved to be the maximum VOCs in studied crude oils. Therefore, a predictive method using n-pentane as a representative component is proposed in this paper. Firstly, a headspace solid phase microextraction (SPME) method was developed for determination of n-pentane in non-equilibrium mass transfer conditions. Secondly, Brunauer-Emmett-Teller (BET) analysis with liquid nitrogen was carried out to predict isotherm parameters for n-pentane. Finally, two models were used to predict the emission process. Probably influenced by gas vapor density below and above the soil layer, the experimental data amounted to 74% of the deduced value from the simplified analytical model. However, the free diffusion model fitted well with the experimental results. PMID:26026407

  20. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  1. 40 CFR 60.663 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...SOURCES Standards of Performance for Volatile Organic Compound (VOC) Emissions From Synthetic Organic Chemical Manufacturing Industry (SOCMI) Distillation Operations § 60.663 Monitoring of emissions and operations. (a)...

  2. 40 CFR 60.663 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...SOURCES Standards of Performance for Volatile Organic Compound (VOC) Emissions From Synthetic Organic Chemical Manufacturing Industry (SOCMI) Distillation Operations § 60.663 Monitoring of emissions and operations. (a)...

  3. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  4. Nickel Compounds

    Cancer.gov

    Nickel is a silvery-white metallic element found in the earth’s crust. It can be combined with other elements to form nickel compounds. Because of its unique properties, nickel has many industrial uses. Most nickel is used in metal alloys because it imparts useful properties, such as corrosion resistance, heat resistance, hardness, and strength.

  5. Investigating the response of East Asian ozone to Chinese emission changes using a linear approach

    NASA Astrophysics Data System (ADS)

    Yamaji, Kazuyo; Uno, Itsushi; Irie, Hitoshi

    2012-08-01

    To illuminate the issue of trans-boundary O3 pollution and regional O3 reduction policies in East Asia, we have investigated the East Asian ozone (O3) response to perturbations caused by Chinese anthropogenic emissions using the Community Multiscale Air Quality (CMAQ) model, a regional chemical transport model. The O3 responses have been examined for the range between -100 and +100% changes from the Chinese emissions level in 2004 in 10% intervals. We have found that springtime and summertime O3 responses both at the source and at the downwind areas can be regarded as linear over the range between -30 and +100% changes from the current emissions level. We therefore suggest that the perturbation between -30 and +100% is sufficiently small to avoid nonlinear chemical influence on O3 formation in a model experiment to investigate East Asian scale O3 source-receptor relationships. On the other hand, the O3 response is strongly nonlinear in April at Hong Kong, where the current NMVOCs/NOx ratio is low and the O3 production regime is easily moved to the NMVOCs sensitive region. The O3 responses to the NOx emission changes have been investigated using surface O3 concentrations at remote Japanese sites and tropospheric NO2 vertical column density (NO2 VCD) over central east China both with observations and with model simulations in springtime during 2003-2009. Analysis of satellite data shows that the observed range of NO2 VCD over central east China in 2003-2009 is the range between -25 and +34% from the 2004 level, which corresponds approximately to an emission variation between -21 and +29%. The O3 concentration in the downwind region during 2003-2009 responds linearly to a change of the NO2 VCD over central east China both in the model and in the observation. The corresponding O3 responses derived from surface observations at remote Japanese sites show linear features consistent with this expectation. The doubling of emissions, i.e., approximately 1.9-fold increase in the NO2 VCD from 2004, leads to O3 increments of 5 ppbv and 8 ppbv in the model and in the observation, respectively. The modeled O3 increase due to changes in NOx emission explains approximately 60% of the observed O3 trend at remote Japanese sites. Thus, approximately 40% of the observed O3 increase is unaccounted for by the NOx emissions growth.

  6. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  7. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  8. Aroma Compounds

    Microsoft Academic Search

    Syed G. Dastager

    The increasing demand for natural products in the food industry has encouraged remarkable efforts towards the development\\u000a of biotechnological processes for the production of aroma compounds. This chapter deals with major achievements reported in\\u000a this field, with a special emphasis on the potential lying in plant cell, microbial cultures and enzyme technology for the\\u000a production of a wide range of

  9. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  10. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  11. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  12. 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...

  13. Importance of activity data for improving the residential wood combustion emission inventory at regional level

    NASA Astrophysics Data System (ADS)

    Pastorello, Cinzia; Caserini, Stefano; Galante, Silvia; Dilara, Panagiota; Galletti, Fabio

    2011-06-01

    The contribution of residential wood combustion (RWC) to emission inventory at local level was estimated using a bottom-up approach for the Lombardy Region of North Italy. A survey, based on the CATI (Computer Assisted Telephone Interviewing) method, has been undertaken through 18,000 interviews. The interviews had the objective to characterize the RWC use in this region, in term of both total and municipal wood consumption. Details on the type of appliances used in RWC were also gathered. The results of the survey were then statistically analyzed in order to allow an estimate of RWC with high spatial resolution (i.e., at municipal level) in relation to the size and altitude of the territory. The work provides new evidence of the importance of wood combustion as a key source for PM and NMVOC emissions at local level, and thus highlights the importance of technological improvements and new policies aimed at emission reduction in this sector. Considering the great differences in average PM emission factors between low efficiency appliances (fireplaces, old stoves) and high efficiency ones (new stoves, pellet burners), this work emphasizes the importance of obtaining more detailed information on the types of wood appliances used for arriving at a reliable PM emission inventory for RWC.

  14. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  15. Model study of the ship emissions impact on the air quality in the Adriatic/Ionian area

    NASA Astrophysics Data System (ADS)

    Karagiannidis, Athanasios; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spiros; Giannaros, Christos; Melas, Dimitrios; Argiriou, Athanassios

    2015-04-01

    The increase of the ship traffic for touristic and commercial purposes is one of the EU Blue Growth targets. The Adriatic/Ionian is one of the sea-basin strategic areas for this target. The purpose of the study is the examination of the impact of the ship emissions on the gaseous and particulate pollutants concentrations in the Adriatic/Ionian area for which the current scientific knowledge is limited. The impact is simulated over a domain covering the Central and Eastern Mediterranean in 10 km resolution during a summer period (July) and a winter period (January) of the year 2012. The modeling system used consists of the photochemical model CAMx off line coupled with the meteorological model WRF. The zero-out modeling method is implemented involving CAMx simulations performed while including and omitting the ship emission data. The simulations are based on the European scale anthropogenic emission inventory of The Netherlands Organisation (TNO) for the reference year 2009. Natural emissions (NMVOCs from the vegetation, sea salt, wind-blown dust), estimated with the use of the Natural Emission MOdel (NEMO) developed by the Aristotle University of Thessaloniki, are accounted for in the photochemical model runs. The spatial distribution of the resulting differences in the gaseous and particulate pollutant concentration fields for both emission scenarios are presented and discussed, providing an estimation of the contribution of ship emissions on the determination of the air quality in the Adriatic/Ionian countries

  16. Low emission turbo compound engine system

    DOEpatents

    Vuk; Carl T. (Denver, IA)

    2011-05-31

    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.

  17. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  18. Bulk Compounds

    NASA Astrophysics Data System (ADS)

    Beaumale, M.; Barbier, T.; Bréard, Y.; Raveau, B.; Kinemuchi, Y.; Funahashi, R.; Guilmeau, E.

    2014-06-01

    The thermoelectric properties of Nb-substituted TiS2 compounds have been investigated in the temperature range of 300 K to 700 K. Polycrystalline samples in the series Ti1- x Nb x S2 with x varying from 0 to 0.05 were prepared using solid-liquid-vapor reaction and spark plasma sintering. Rietveld refinements of x-ray diffraction data are consistent with the existence of full solid solution for x ? 0.05. Transport measurements reveal that niobium can be considered as an electron donor when substituted at Ti sites. Consequently, the electrical resistivity and the absolute value of the Seebeck coefficient decrease as the Nb content increases, due to an increase in the carrier concentration. Moreover, due to mass fluctuation, the lattice thermal conductivity is reduced, leading to a slight increase of ZT values as compared with TiS2.

  19. Low emissions diesel fuel

    DOEpatents

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

    1998-01-01

    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.

  20. Synthesis of Fluorinated ZDDP Compounds

    Microsoft Academic Search

    Kajal Parekh; Xin Chen; Pranesh B. Aswath

    2009-01-01

    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

  1. Future prediction of surface ozone over east Asia using Models-3 Community Multiscale Air Quality Modeling System and Regional Emission Inventory in Asia

    NASA Astrophysics Data System (ADS)

    Yamaji, Kazuyo; Ohara, Toshimasa; Uno, Itsushi; Kurokawa, Jun-Ichi; Pochanart, Pakpong; Akimoto, Hajime

    2008-04-01

    Present and future tropospheric ozone (O3) concentrations over east Asia have been simulated by the Models-3 Community Multiscale Air Quality Modeling System (CMAQ) coupled with the Regional Emission Inventory in Asia (REAS) to predict surface O3 variations caused by future anthropogenic emissions changes. For future prediction, REAS provides three emission scenarios for China (the reference (REF), the policy succeed case (PSC), and the policy failure case (PFC) scenarios) and one emission scenario (the REF scenario) for the other countries. Simulated O3 concentration in summer was relatively high (70-80 ppbv in June and 65-75 ppbv in August) over the North China Plain in 2000. The projected REF emissions for 2020 (2020REF) enhance the monthly averaged O3 to 75-90 ppbv in June and 75-85 ppbv in August. The projected PSC emissions for 2020 (2020PFC), including a slight NOx reduction of -0.2 Tg (-2%) and a large NMVOC increase of 14.3 Tg (97%) for total Chinese emissions during 2000-2020, cause the monthly and annually averaged O3 concentrations to decrease by less than 2 ppbv in northeastern and central China. Over the North China Plain, the projected PFC emissions for 2020 (2020PFC) cause significant increases, more than 20 ppbv in the monthly averaged O3, and the O3 will be 85-105 ppbv in June and 80-95 ppbv in August for 2020. The 2020PFC also affect O3 increases in early summer in South Korea (14-18 ppbv increase for monthly average) and Japan (2-14 ppbv increase for monthly average) during 2000-2020 despite the slight NOx increase of 0.4 Tg (25%) in South Korea and the slight NOx reduction of -0.2 Tg (-10%) in Japan during 2000-2020. The pollutant in these regions seems to be transport from upwind source regions. These experiments show that over central eastern China at midday in June, the O3 concentration is largely affected by NOx emission increases but is insensitive to NMVOC emission increases.

  2. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2012-10-23

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  3. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2013-03-19

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  4. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2010-09-07

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  5. LEVEL SET REGULARIZATION IN POSITRON EMISSION TOMOGRAPHY 1 Level Set Method for Positron Emission

    E-print Network

    Chan, Tony F.

    LEVEL SET REGULARIZATION IN POSITRON EMISSION TOMOGRAPHY 1 Level Set Method for Positron Emission for integrated Petroleum Research). #12;LEVEL SET REGULARIZATION IN POSITRON EMISSION TOMOGRAPHY 2 Abstract In positron emission tomography (PET) a radioactive compound is injected into the body to promote a tissue

  6. Modeling an air pollution episode in northwestern United States: Identifying the effect of nitrogen oxide and volatile organic compound emission changes on air pollutants formation using direct sensitivity analysis

    Microsoft Academic Search

    Alexandra P. Tsimpidi; Marcus Trail; Yongtao Hu; Athanasios Nenes; Armistead G. Russell

    2012-01-01

    Air quality impacts of VOCs and NOx emissions from major sources over the northwestern United States are simulated. The comprehensive nested modeling system is comprised of three models: CMAQ, WRF and SMOKE. In addition, the DDM-3D is used to determine the sensitivities of pollutant concentrations to changes in precursor emissions during a severe smog episode in July of 2006. The

  7. 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...

  8. Review of jet engine emissions.

    NASA Technical Reports Server (NTRS)

    Grobman, J. S.

    1972-01-01

    The various constituents in jet engine exhaust during typical takeoff or cruise conditions are presented in a table. The categories considered include inerts and unreacted oxygen from air, products of complete combustion of fuel, products of incomplete combustion, oxides of nitrogen formed during the heating of air, and elements or compounds derived from sulfur and trace metals present in kerosene fuel. Typical jet engine emission characteristics are discussed together with the effect of operating variables on emissions, and combustor design techniques to reduce emissions. Particular attention is given to emissions in the upper atmosphere, and to methods to reduce nitric oxide emissions.

  9. Inherently low-emission vehicle program, estimated emission benefits and impact on high-occupancy vehicle lanes. Technical report

    Microsoft Academic Search

    Wyborny

    1992-01-01

    According to the detailed analysis in the report, ILEVs would provide substantial emission reductions compared to LEVs and other conventional vehicles. The evaporative and refueling emissions (vapor emissions) from ILEVs are estimated to be near zero. With the near-elimination of vapor emissions, ILEVs are expected to emit about one-half the volatile organic compound emissions as other LEVs. The report also

  10. Historical gaseous and primary aerosol emissions in the United States from 1990-2010

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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, 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 Emission 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 equipments 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 and NOx emissions agree well with the observed changes in ambient SO2 and NO2 concentrations, suggesting that the various controls on SO2 and NOx 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.

  11. Sanskrit Compound Processor

    NASA Astrophysics Data System (ADS)

    Kumar, Anil; Mittal, Vipul; Kulkarni, Amba

    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.

  12. PHOBEA\\/ITCT 2002 airborne observations of transpacific transport of ozone, CO, volatile organic compounds, and aerosols to the northeast Pacific: Impacts of Asian anthropogenic and Siberian boreal fire emissions

    Microsoft Academic Search

    I. T. Bertschi; D. A. Jaffe; L. Jaegle; J. B. Dennison

    2004-01-01

    (1) During the spring of 2002, vertical profiles of O3, CO, nonmethane volatile organic compounds (VOCs), and total aerosol scattering were collected over the northwestern coast of Washington State as part of the University of Washington's Photochemical Ozone Budget of the Eastern North Pacific Atmosphere (PHOBEA) research campaign. These observations coincided with NOAA's Intercontinental Transport and Chemical Transformation 2002 (NOAA-ITCT

  13. Air emissions inventory for the Idaho National Engineering Laboratory -- 1995 emissions report

    SciTech Connect

    NONE

    1996-06-01

    This report presents the 1995 update of the Air Emission Inventory for the Idaho National Engineering Laboratory (INEL). The INEL Air Emission Inventory documents sources and emissions of non-radionuclide pollutants from operations at the INEL. The report describes the emission inventory process and all of the sources at the INEL, and provides non-radionuclide emissions estimates for stationary sources. The air contaminants reported include nitrogen oxides, sulfur oxides, carbon monoxide, volatile organic compounds, particulates, and hazardous air pollutants (HAPs).

  14. An Improved Emission Inventory of Crop Residue Burning in Fields in China Based on Statistics and MODIS Fire Products

    NASA Astrophysics Data System (ADS)

    Jing, L.

    2014-12-01

    Agricultural field burning plays an important role in atmospheric pollution and climate change. Current air quality simulation exhibits significant error in crop residue burning season. A high quality emission inventory is the foremost requirement for air quality model simulation. The development of such sporadic emission sources emission inventory is always challenging. Currently, satellite-based burned area methodologies specifically calibrated for crop residue burning are limited, whereas the combination of statistical date and satellite date will improve the accuracy of the result. This work aims to develop a higher accuracy emission inventory for agricultural burning in China and analyze its temporal and spatial distributions. Province-specific statistical data, distributed by the Chinese national government were utilized to estimate the total amount of crop residue burning for the year 2012. Specifically, on the basis of China's realities we applied the latest China's grain-to-straw ratio and used agriculture mechanization ratio for the first time to calculate the burning amount of crop residue. Based on the newest local experimental emission factors by province and crop type, the total amounts of TSP, PM10, S02, NOX, NH3, CH4, EC, OC, NMVOCs, CO and CO2, emitted from crop residue burning in the field, were estimated. Emissions were allocated to a 40km×40km grid and 10-day interval by MODIS Fire product(MOD/MYD14A1). To reduce the impact of missing fire counts we modified the satellite date by statistical analysis. Our inventory applied the most detailed and latest activity date and improved the problem of satellite products' limitation for crop residue burning in fields. Our approach provides a more consistent methodology for quantifying the emission of crop residue burning than the previously available method and our emission inventory could meet the need of air quality simulations.

  15. TANKS Emissions Estimation Software, Version 4.09D

    EPA Science Inventory

    TANKS is a Windows-based computer software program that estimates volatile organic compound (VOC) and hazardous air pollutant (HAP) emissions from fixed- and floating-roof storage tanks. TANKS is based on the emission estimation procedures from ...

  16. 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...

  17. 40 CFR 60.703 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...STATIONARY SOURCES Standards of Performance for Volatile Organic Compound Emissions From Synthetic Organic Chemical Manufacturing Industry (SOCMI) Reactor Processes § 60.703 Monitoring of emissions and operations. (a) The...

  18. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    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.

  19. 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...

  20. Regulating compounding pharmacies.

    PubMed

    Noble, Ashley

    2015-06-01

    (1) The Pew Charitable Trusts identified 27 compounding incidents that resulted in 89 deaths since 2001. (2) Unlike drug manufacturers, compounding pharmacies are generally not required to report adverse events associated with their products to the FDA. (3) Federal law on drug compounding was updated in 2013 to create a new group of compounders called "outsourcing facilities." Over 50 facilities in 23 states are now registered with the FDA. PMID:26137607

  1. Container compounds - stable systems

    SciTech Connect

    Petrov, S.V.; Tatevskii, V.M.; Yarovoi, S.S.; Bolotin, A.B.

    1985-09-01

    The authors studied the question of the stability of container compounds. As stability criteria the authors use the lifetime of the container compound. Quantitative estimates were obtained by drawing on the theory of quasistationary (resonance) states. The energy levels and the lifetimes for these levels, which are the lifetimes for the container compounds, are calculated with subsequent consideration of the Schroedinger equation. Numerical characteristics are obtained for various container compounds.

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

    EPA Science Inventory

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

  3. Positron-emission tomography

    SciTech Connect

    Ter-Pogossian, M.M.; Raichle, M.E.; Sobel, B.E.

    1980-10-01

    Positron-emission tomography (PET) combines early biochemical assessment of pathology achieved by nuclear medicine with the precise localization achieved by computerized image reconstruction. In this technique a chemical compound with the desired biological activity is labeled with a radioactive isotope that decays by emitting a positron, or positive electron. With suitable interpretation PET images can provide a noninvasive, regional assessment of many biochemical processes that are essential to the functioning of the organ that is being visualized.

  4. Evaluation of different derivatization methods for the multi-element detection of Hg, Pb and Sn compounds by gas chromatography-microwave induced plasma-atomic emission spectrometry in environmental samples

    Microsoft Academic Search

    V. Minganti; R. Capelli; R. De Pellegrini

    1995-01-01

    A multi-element, element-specific detector for gas chromatography (GC) based on atomic emission spectroscopy (AES) with a microwave induced plasma (MIP) source was tested on some environmental samples. As derivatization procedure, direct aqueous phase ethylation and chelation\\/extraction followed by Grignard reaction were tested on the following ions: methylmercury, ethylmercury, phenylmercury, mercury(II), trimethyllead, dimethyllead, lead(II), trimethyltin, dimethyltin, triethyltin, tripropyltin, tributyltin, dibutyltin, butyltin,

  5. Evaluation of a purge-and-trap injection system for capillary gas chromatography-microwave induced plasma-atomic emission spectrometry for the determination of volatile selenium compounds in water

    Microsoft Academic Search

    María Beatriz de la Calle Guntiñas; Michiel Ceulemans; Claudia Witte; Ryszard ?obi?ski; Freddy C. Adams

    1995-01-01

    A method is presented for the selective determination of the volatile selenium species dimethylselenide and dimethyldiselenide, using a commercially available purge-and-trap injection system coupled to capillary gas chromatography-microwave induced plasma-atomic emission spectrometry. The efficiency of the purging step was evaluated and the parameters affecting the purge and trap processes were optimized. The method was applied to the determination of volatile

  6. Emission reduction

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

  7. Atmospheric peroxyacetyl nitrate (PAN): a global budget and source attribution

    NASA Astrophysics Data System (ADS)

    Fischer, E. V.; Jacob, D. J.; Yantosca, R. M.; Sulprizio, M. P.; Millet, D. B.; Mao, J.; Paulot, F.; Singh, H. B.; Roiger, A.-E.; Ries, L.; Talbot, R. W.; Dzepina, K.; Pandey Deolal, S.

    2013-10-01

    Peroxyacetyl nitrate (PAN) formed in the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs), is the principal tropospheric reservoir for nitrogen oxide radicals (NOx = NO + NO2). PAN enables the transport and release of NOx to the remote troposphere with major implications for the global distributions of ozone and OH, the main tropospheric oxidants. Simulation of PAN is a challenge for global models because of the dependence of PAN on vertical transport as well as complex and uncertain NMVOC sources and chemistry. Here we use an improved representation of NMVOCs in a global 3-D chemical transport model (GEOS-Chem) and show that it can simulate PAN observations from aircraft campaigns worldwide. The immediate carbonyl precursors for PAN formation include acetaldehyde (44% of the global source), methylglyoxal (30%), acetone (7%), and a suite of other isoprene and terpene oxidation products (19%). A diversity of NMVOC emissions is responsible for PAN formation globally including isoprene (37%) and alkanes (14%). Anthropogenic sources are dominant in the extratropical Northern Hemisphere outside the growing season. Open fires appear to play little role except at high northern latitudes in spring, although results are very sensitive to plume chemistry and plume rise. Lightning NOx is the dominant contributor to the observed PAN maximum in the free troposphere over the South Atlantic.

  8. Atmospheric peroxyacetyl nitrate (PAN): a global budget and source attribution

    NASA Astrophysics Data System (ADS)

    Fischer, E. V.; Jacob, D. J.; Yantosca, R. M.; Sulprizio, M. P.; Millet, D. B.; Mao, J.; Paulot, F.; Singh, H. B.; Roiger, A.; Ries, L.; Talbot, R. W.; Dzepina, K.; Pandey Deolal, S.

    2014-03-01

    Peroxyacetyl nitrate (PAN) formed in the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs) is the principal tropospheric reservoir for nitrogen oxide radicals (NOx = NO + NO2). PAN enables the transport and release of NOx to the remote troposphere with major implications for the global distributions of ozone and OH, the main tropospheric oxidants. Simulation of PAN is a challenge for global models because of the dependence of PAN on vertical transport as well as complex and uncertain NMVOC sources and chemistry. Here we use an improved representation of NMVOCs in a global 3-D chemical transport model (GEOS-Chem) and show that it can simulate PAN observations from aircraft campaigns worldwide. The immediate carbonyl precursors for PAN formation include acetaldehyde (44% of the global source), methylglyoxal (30%), acetone (7%), and a suite of other isoprene and terpene oxidation products (19%). A diversity of NMVOC emissions is responsible for PAN formation globally including isoprene (37%) and alkanes (14%). Anthropogenic sources are dominant in the extratropical Northern Hemisphere outside the growing season. Open fires appear to play little role except at high northern latitudes in spring, although results are very sensitive to plume chemistry and plume rise. Lightning NOx is the dominant contributor to the observed PAN maximum in the free troposphere over the South Atlantic.

  9. Thiophenic Sulfur Compounds Released During Coal Pyrolysis.

    PubMed

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-06-01

    Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography-mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

  10. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

    PubMed Central

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-01-01

    Abstract Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography–mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

  11. Volatile organic compound (VOC) control in ethylene plants

    SciTech Connect

    Grover, R.; Gomaa, H.M. [M.W. Kellogg Co., Houston, TX (United States)

    1994-12-31

    Volatile Organic Compounds (VOC) are compounds of carbon that combine with nitrogen oxides and other airborne chemicals, in the presence of sunlight (photochemically), to form ozone, which is a primary component of smog. Some common VOC include: benzene, toluene, xylene, naphtha, ethylene oxide, methyl ethyl ketone, acetone, and 1,3-Butadiene. Pollution of the atmosphere by VOC has been a subject of major concern. Therefore, VOC emissions are attracting increasing concern from public and government agencies. Ethylene plants have many multiple sources of VOC emissions. These sources can be divided into point emission sources, both continuous and intermittent, and fugitive emission sources. This paper discusses VOC emissions and controls for ethylene plants. The impact of environmental regulations are discussed with respect to new and existing ethylene plants. Typical VOC emission rates are quantified. Commercially available and emerging control technologies are reviewed.

  12. Transportation emissions in Lebanon: Extent and mitigation

    E-print Network

    Bou-Zeid, Elie

    including: nitrogen oxides NOx, carbon monoxide CO, sulfur dioxide SO2, volatile organic compounds VOC quality led many countries to impose strict regulations on gas emission rates and vehicle fuel economy

  13. Preparation of uranium compounds

    DOEpatents

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

    2013-02-19

    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.

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

    NASA Astrophysics Data System (ADS)

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

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

  15. Analysis of volatile organic compounds from illicit cocaine samples

    SciTech Connect

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

    1994-07-01

    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.

  16. REDUCTION OF EMISSIONS FROM IN VITRO SWINE MANURE USING MONENSIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Storage of swine manure is associated with the generation of malodorous compounds and emissions. These are produced as a result of anaerobic degradation of materials present in manure and include sulfides, methane, organic acids, ammonia, and other volatile compounds. Because odor emission from li...

  17. Spontaneous and stimulated emission in the mid-ultraviolet range of quantum-well heterostructures based on AlGaN compounds grown by molecular beam epitaxy on c-sapphire substrates

    NASA Astrophysics Data System (ADS)

    Lutsenko, E. V.; Rzheutskii, N. V.; Pavlovskii, V. N.; Yablonskii, G. P.; Nechaev, D. V.; Sitnikova, A. A.; Ratnikov, V. V.; Kuznetsova, Ya. V.; Zhmerik, V. N.; Ivanov, S. V.

    2013-10-01

    This paper reports on the results of investigations of the spontaneous and stimulated luminescence in AlGaN heterostructures with a single quantum well and a high Al content (up to ˜80 mol % in barrier layers), which were grown by plasma assisted molecular beam epitaxy (PAMBE) on c-sapphire substrates. It has been demonstrated that the stimulated emission occurs in the mid-ultraviolet range of the spectrum at wavelengths of 259, 270, and 289 nm with threshold excitation power densities of 1500, 900, and 700 kW/cm2, respectively. It has been shown that there exists a possibility of TE polarization ( E ? c) of both stimulated and spontaneous luminescence down to wavelengths of 259 nm.

  18. Alkyllead compounds and their environmental toxicology.

    PubMed

    Abadin, Henry G; Pohl, Hana R

    2010-01-01

    Alkyllead compounds are man-made compounds in which a carbon atom of one or more organic molecules is bound to a lead atom. Tetraethyllead and tetramethyllead are the most common alkyllead compounds that were used primarily as gasoline additives for many years. Consequently, auto emissions have accounted for a major part of lead environmental pollution. Alkyllead compounds can readily enter living organisms as they are well absorbed via all major routes of entry. Because of their lipid solubility, the alkylleads can also readily cross the blood-brain barrier. The toxicokinetic information on organic lead can be used as biomarkers of exposure for monitoring exposed individuals. The organic alkyllead compounds are more toxic than the inorganic forms of lead. Neurotoxicity is the predominant effect of lead (both for organic and inorganic forms), although lead affects almost every organ of the body. The use of alkyllead compounds has declined over the last 20 years, due to the worldwide effort to eliminate the use of leaded gasoline. This achievement can be viewed as a great accomplishment of public health preventive measures. PMID:20877807

  19. Real-time trace detection of vapor-phase elemental mercury and its compounds

    Microsoft Academic Search

    Xiaomei Tong; Robert B. Barat; Arthur T. Poulos

    1999-01-01

    The high toxicity of mercury species (elemental and compound) has prompted a demand for accurate, real-time inventory and control of their emissions. Our method of choice for mercury compound vapor is Photofragment Fluorescence spectroscopy. Target compound concentrations can be related to the fluorescence intensity from an excited fragment. Fragment identities and distributions, as revealed in the fluorescence spectrum provide information

  20. Odor-causing volatile organic compounds in wastewater treatment plant units and sludge management areas

    Microsoft Academic Search

    Faruk Dincer; Aysen Muezzinoglu

    2008-01-01

    Odors due to malodorous gas and vapor emissions from units of Izmir Wastewater Treatment Plant (WWTP) were studied and evaluated with respect to chemical composition. Altogether 29 target compounds consisting of 4 different groups of chemicals were identified and quantified in the odorous gas samples from wastewater and sludges. Total volatile malodorous organic compounds (VMOC) consisted of reduced sulfur compounds

  1. Impact of an improved Cuban emissions inventory on air quality simulations

    NASA Astrophysics Data System (ADS)

    Sanchez Gacita, M.; Alonso, M. F.; Longo, K. M.; de Freitas, S. R.

    2010-12-01

    The energy sector in the Central America and Caribbean regions is primarily fossil fuel based and one of the major sources of air pollution in the region. In Cuba, energy production is responsible for 99% of SO2 emissions, 98% of NOX and 94% of CO, with emissions in 2000 of 588.59 Gg, 149.57 Gg and 536.42 Gg, respectively, according to the Cuban National Inventory - CNI. Electric power generation plants, the most important sub-sector, are highlighted as point sources of high emissions, in particular, SO2. Global inventories are shown to be inaccurate for Cuba. RETRO has non-zero data for just one cell, over the city of Havana. EDGAR has deficiencies in its geographical distribution, with no emissions over the city of Havana, and the distribution of emissions by sectors is unrealistic according to the CNI: for instance, in the case of SO2, it distributes emissions nearly equally between electricity generation and the remaining sectors, which is inaccurate. More importantly, emissions are overestimated, with the notable exception of SO2 and NMVOC. The most important reasons are the particularities of Cuba, including the extensive employ of fossil fuels with little refining and high sulfur content in energy production and industrial processes such as asphalt production, and the use of low efficiency technologies. This work presents an improved emissions inventory with CNI data and detailed emissions for all major power generation plants. The impact of this improvement was assessed through numerical air quality simulations of the transport and transformation of these emissions from a regional perspective, conducted with the CCATT-BRAMS 3D atmospheric chemical transport model, developed and maintained by INPE, Brazil. Boundary conditions were supplied by global model MOCAGE with chemistry scheme RELACS. Simulations with the new inventory were conducted with CATT-BRAMS using chemical mechanism RELACS, incorporated as part of this work, for two months (January and August) of 2008, and the differences found for the observed patterns for the dispersion of pollutants at a regional scale are discussed. The behavior of the model was evaluated through sensitivity tests.

  2. Assessment of biomass open burning emissions in Indonesia and potential climate forcing impact

    NASA Astrophysics Data System (ADS)

    Permadi, Didin Agustian; Kim Oanh, Nguyen Thi

    2013-10-01

    This paper presents an emission inventory (EI) for biomass open burning (OB) sources including forest, agro-residue and municipal solid waste (MSW) in Indonesia for year 2007. The EI covered toxic air pollutants and greenhouse gases (GHGs) and was presented as annual and monthly average for every district, and further on a grid of 0.25° × 0.25°. A rigorous analysis of activity data and emission factor ranges was done to produce the low, best and high emission estimates for each species. Development of EI methodology for MSW OB which, to our best knowledge, has not been presented in detail in the literature was a focus of this paper. The best estimates of biomass OB emission of toxic air pollutants for the country, in Gg, were: 9.6 SO2; 98 NOx; 7411 CO; 335 NMVOC; 162 NH3; 439 PM10; 357 PM2.5; 24 BC; and 147 OC. The best emission estimates of GHGs, in Gg, were: 401 CH4, 57,247 CO2; and 3.6 N2O. The low and high values of the emission estimates for different species were found to range from -86% to +260% of the corresponding best estimates. Crop residue OB contributed more than 80% of the total biomass OB emissions, followed by forest fire of 2-12% (not including peat soil fire emission) and MSW (1-8%). An inter-annual active fires count for Indonesia showed relatively low values in 2007 which may be attributed to the high rainfall intensity under the influence of La Niña climate pattern in the year. Total estimated net climate forcing from OB in Indonesia was 110 (20 year horizon) and 73 (100 year horizon) Tg CO2 equivalents which is around 0.9-1.1% of that reported for the global biomass OB for both time horizons. The spatial distribution showed higher emissions in large urban areas in Java and Sumatra Island, while the monthly emissions indicated higher values during the dry months of August-October.

  3. Bioavailability of Phenolic Compounds

    Microsoft Academic Search

    SIBEL KARAKAYA

    2004-01-01

    Phenolic compounds in foods originate from one of the main classes of secondary metabolites in plants. They are essential for the growth and reproduction of plants, and are produced as a response for defending injured plants against pathogens. In recent years, there is a growing interest in phenolic compounds and their presumed role in the prevention of various degenerative diseases,

  4. Analyzing Cranberry Bioactive Compounds

    Microsoft Academic Search

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

    2010-01-01

    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

  5. 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...

  6. EMISSION RATES FOR BIOGENIC NOX

    EPA Science Inventory

    A literature review of biogenic sources of NOx was conducted to determine their emission rates into the atmosphere. NOx are some of the products of microbial denitrification, chemical decomposition of nitrites and the oxidation of organic nitrogen compounds. There appears to be n...

  7. Ethanol emission from loose corn silage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silage and silage-containing feed on dairy farms have recently been identified as a source of volatile organic compound (VOC) emissions. In this work, we present measurements of ethanol (a dominant silage VOC) emission from loose corn silage samples made using a wind tunnel system. Flux of ethanol f...

  8. 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...

  9. A reassessment of the budget of formic and acetic acids in the boundary layer at Dumont d'Urville (coastal Antarctica): The role of penguin emissions on the budget of several oxygenated volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Legrand, Michel; Gros, ValéRie; Preunkert, Susanne; Sarda-EstèVe, Roland; Thierry, Anne-Mathilde; PéPy, Guillaume; Jourdain, B.

    2012-03-01

    Initiated in 1997, the year-round study of formic and acetic acids was maintained until 2011 at the coastal Antarctic site of Dumont d'Urville. The records show that formic and acetic acids are rather abundant in summer with typical mixing ratios of 200 pptv and 700 pptv, respectively. With the aim to constrain their budget, investigations of their potential marine precursors like short-chain alkenes and acetaldehyde were initiated in 2011. Acetic acid levels in December 2010 were four times higher than those observed over summers back to 1997. These unusually high levels were accompanied by unusually high levels of ammonia, and by an enrichment of oxalate in aerosols. These observations suggest that the guano decomposition in the large penguin colonies present at the site was particularly strong under weather conditions encountered in spring 2010 (important snow storms followed by sunny days with mild temperatures). Although being dependent on environmental conditions, this process greatly impacts the local atmospheric budget of acetic acid, acetaldehyde, and acetone during the entire summer season. Present at levels as high as 500 pptv, acetaldehyde may represent the major precursor of acetic acid, alkene-ozone reactions remaining insignificant sources. Far less influenced by penguin emissions, the budget of formic acid remains not fully understood even if alkene-ozone reactions contribute significantly.

  10. Emission estimates for air pollution transport models.

    SciTech Connect

    Streets, D. G.

    1998-10-09

    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.

  11. Organic Compounds Database

    NSDL National Science Digital Library

    Bell, Harold M.

    2000-01-01

    The Colby College Department of Chemistry offers the Organic Compounds Database, which was compiled by Harold Bell of the Virginia Polytechnic Institute. Visitors can search by the compounds melting point, boiling point, index of refraction, molecular weight, formula, absorption wavelength, mass spectral peak, chemical type, and by partial name. Once entered, results are returned with basically the same type of information that can be searched, plus any other critical information. References are provided for the close to 2500 organic compounds included in the database; yet, because the site was last modified in 1995, varying the data may be required to fully authenticate its accuracy.

  12. Emissions of air toxics from a simulated charcoal kiln. Final report, October 1997September 1998

    Microsoft Academic Search

    Lemieux

    1999-01-01

    The report gives results of experiments in a laboratory-scale charcoal kiln simulator to evaluate emissions of hazardous air pollutants from the production of charcoal in Missouri-type kilns. Fixed combustion gases were measured using continuous monitors. In addition, other pollutants, including methanol, volatile organic compounds, semivolatile organic compounds, and particle emission rates and size distributions were measured using various techniques. Emissions

  13. Emissions of air toxics from the production of charcoal in a simulated Missouri charcoal kiln

    Microsoft Academic Search

    P. M. Lemieux; P. H. Kariher; B. J. Fairless; J. A. Tapp

    1998-01-01

    The paper gives results of experiments in a laboratory-scale charcoal kiln simulator to evaluate emissions of hazardous air pollutant from the production of charcoal in Missouri-type kilns. Fixed combustion gases were measured using continuous monitors. In addition, other pollutants, including methanol, volatile organic compounds, semivolatile organic compounds, and particle emission rates and size distributions were measured using various techniques. Emissions

  14. Heart testing compound

    DOEpatents

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

    1983-06-29

    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.

  15. MANUFACTURE OF LIMONOID COMPOUNDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present invention relates to methods for manufacturing limonoid compounds. The invention provides methods for isolating limonoid A-ring lactone acid salts, limonoid glycoside monocarboxylic acids, limonoid glycoside dicarboxylic acids, limonoid glycoside monocarboxylic acid salts, and limonoid ...

  16. Compound Independent Events

    NSDL National Science Digital Library

    2007-12-12

    Compare the theoretical and experimental probabilities of compound independent events by drawing colored marbles from a bag. Record the results of successive draws with or without replacement of marbles to calculate the experimental probability.

  17. Ringed-Carbon Compounds

    NSDL National Science Digital Library

    WGBH Educational Foundation

    2007-02-12

    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.

  18. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  19. Ultraviolet radiation screening compounds

    Microsoft Academic Search

    CHARLES S. COCKELL; JOHN KNOWLAND

    1988-01-01

    Amongst the diversity of methods used by organisms to reduce damage caused by ultraviolet (UV) radiation, the synthesis of UV-screening compounds is almost ubiquitous. UV-screening compounds provide a passive method for the reduction of UV-induced damage and they are widely distributed across the microbial, plant and animal kingdoms. They share some common chemical features. It is likely that on early

  20. Characterization of Industrial Emission Sources and Photochemistry in Houston, Texas

    Microsoft Academic Search

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

    2009-01-01

    The Houston-Galveston urban area contains a number of large industrial petrochemical emission sources that produce volatile organic compounds and nitrogen oxides. These co-located emissions result in rapid and efficient ozone production downwind. Unlike a single large power plant, the industrial complexes consist of numerous sources that can be difficult to quantify in emission inventories. During September - October 2006, the

  1. A farm-level model of VOC emission from silage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent measurements suggest that dairy farms can be a significant emission source of volatile organic compounds (VOCs). However, accurate estimates of farm-level emissions currently do not exist. A preliminary process-based model was developed to estimate VOC emissions from silage on farms and to as...

  2. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    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 PM 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) with 2005 emissions and 2020 emission scenarios. Under REF[0] emissions, the concentrations of SO2, NO2, hourly maximum ozone in summer, PM2.5, total sulfur and nitrogen depositions will increase by 5~47%, 45~53%, 8~12%, 4~15%, 4~37% and 7~14%, respectively, over East China. Under the PC[2] emission scenario, the concentrations of SO2, NO2, hourly maximal ozone in summer, PM2.5, total sulfur and nitrogen depositions will change by -28%~16%, -1%~11%, 1%~2%, -24%~-12%, -24%~13%, and 0~3%, respectively. 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 total nitrogen deposition in the future.

  4. Acoustic emission

    NASA Astrophysics Data System (ADS)

    Asty, M.

    1983-01-01

    A review of acoustic emission methods is presented. These are considered to be a valuable nondestructive technique to evaluate the effect of stresses on materials. The nature of acoustic emissions are described. Techniques which are most suited to industrial applications are emphasized. Codification attempts by ASME and ASTM are discussed.

  5. EFFECTS OF VENTILATION RATES AND PRODUCT LOADING ON ORGANIC EMISSION RATES FROM PARTICLEBOARD

    EPA Science Inventory

    The paper discusses the effects of ventilation rates and product loading on organic emission rates from particleboard. Recently, investigators have confirmed the presence of varied and significant amounts of organic compounds in indoor environment, including compounds known or su...

  6. Variation in isoprene emission from Quercus rubra: Sources, causes, and consequences for estimating fluxes

    E-print Network

    2004; published 17 February 2005. [1] Isoprene is the dominant volatile organic compound produced volatile organic compounds (VOCs) produced by plants that substantially influence atmospheric chemistry isoprene emission. This study applied a variance partitioning approach to identify the major sources

  7. A tetraphenylethene-based caged compound: synthesis, properties and applications.

    PubMed

    Yu, Chris Y Y; Kwok, Ryan T K; Mei, Ju; Hong, Yuning; Chen, Sijie; Lam, Jacky W Y; Tang, Ben Zhong

    2014-08-01

    A tetraphenylethene-based caged compound (TPE-C) is designed and synthesized. TPE-C is non-fluorescent either in solution or in aggregated state, but its emission can be induced to emit strong cyan emission in the aggregated state by UV irradiation. This property enables TPE-C to be applied in photo-patterning and anti-counterfeiting related areas. PMID:24923580

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    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.

  9. Compound droplets on fibers

    E-print Network

    Weyer, Floriane; Hötzer, Johannes; Berghoff, Marco; Dreesen, Laurent; Nestler, Britta; Vandewalle, Nicolas

    2015-01-01

    Droplets on fibers have been extensively studied in the recent years. Although the equilibrium shapes of simple droplets on fibers are well established, the situation becomes more complex for compound fluidic systems. Through experimental and numerical investigations, we show herein that compound droplets can be formed on fibers and that they adopt specific geometries. We focus on the various contact lines formed at the meeting of the different phases and we study their equilibrium state. It appears that, depending on the surface tensions, the triple contact lines can remain separate or merge together and form quadruple lines. The nature of the contact lines influences the behavior of the compound droplets on fibers. Indeed, both experimental and numerical results show that, during the detachment process, depending on whether the contact lines are triple or quadruple, the characteristic length is the inner droplet radius or the fiber radius.

  10. Sulfur compounds in coal

    NASA Technical Reports Server (NTRS)

    Attar, A.; Corcoran, W. H.

    1977-01-01

    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.

  11. Compound Droplets on Fibers.

    PubMed

    Weyer, Floriane; Ben Said, Marouen; Hötzer, Johannes; Berghoff, Marco; Dreesen, Laurent; Nestler, Britta; Vandewalle, Nicolas

    2015-07-21

    Droplets on fibers have been extensively studied in the recent years. Although the equilibrium shapes of simple droplets on fibers are well established, the situation becomes more complex for compound fluidic systems. Through experimental and numerical investigations, we show herein that compound droplets can be formed on fibers and that they adopt specific geometries. We focus on the various contact lines formed at the meeting of the different phases and we study their equilibrium state. It appears that, depending on the surface tensions, the triple contact lines can remain separate or merge together and form quadruple lines. The nature of the contact lines influences the behavior of the compound droplets on fibers. Indeed, both experimental and numerical results show that, during the detachment process, depending on whether the contact lines are triple or quadruple, the characteristic length is the inner droplet radius or the fiber radius. PMID:26090699

  12. Microoptical compound lens

    DOEpatents

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

    2007-10-23

    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.

  13. National Environmental Research Institute University of Aarhus . Denmark

    E-print Network

    . 655, 2008 Projection of SO2 , NOX , NMVOC, NH3 and particle emissions ­ 2005 to 2030 #12;[Blank page. 655, 2008 Projection of SO2, NOX, NMVOC, NH3 and particle emissions ­ 2005 to 2030 Jytte Boll Illerup Gyldenkærne #12;'DWD VKHHW Series title and no.: NERI Technical Report No. 655 Title: Projection of SO2, NOX

  14. 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...

  15. Perfluoroalkyl Nitroso Compounds

    Microsoft Academic Search

    Joan Banus

    1953-01-01

    A PRELIMINARY study1 of the photochemical properties of the first fluorocarbon iodide, trifluoro-iodomethane, showed that a trifluoromethyl radical is produced the primary reactions of which parallel those of the hydrocarbon free radicals. A direct method thus became available for the preparation of perfluoroalkyl nitroso compounds, by irradiation of the iodide in the presence of nitric oxide and of mercury (to

  16. Optimisation of compound pressure

    Microsoft Academic Search

    G. H. Majzoobi; A. Ghomi

    Purpose: The purpose of this paper is optimization of the weight of compound cylinder for a specific pressure. The variables are shrinkage radius and shrinkage tolerance. Design\\/methodology\\/approach: SEQ technique for optimization, the finite element code, ANSYS for numerical simulation are employed to predict the optimized conditions. The results are verified by testing a number of closed end cylinders with various

  17. Compound floating pivot micromechanisms

    DOEpatents

    Garcia, Ernest J. (Albuquerque, NM)

    2001-04-24

    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.

  18. Compound semiconductor radiation detectors

    Microsoft Academic Search

    Alan Owens; A. Peacock

    2004-01-01

    We discuss the potential benefits of using compound semiconductors for the detection of X- and ?-ray radiation. While Si and Ge have become detection standards for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by one or more of their physical limitations; namely the need for ancillary cooling systems or bulky

  19. Arsonium Compounds in Algae

    Microsoft Academic Search

    A. A. Benson

    1989-01-01

    Search for a precursor of the arsenobetaine discovered in Western Australian rock lobster tail muscle has led to an algal metabolite of radioarsenate having the properties of a trimethylarsoniumriboside derivative of the major arsenicals of aquatic plants, dimethylarsinoylribosylglycerol, its sulfate ester, and the corresponding riboside of phosphatidylglycerol. Such an arsonium compound could serve as metabolic precursor of arsenobetaine, the innocuous

  20. Biotransformation of halogenated compounds

    Microsoft Academic Search

    David J. Hardman

    1991-01-01

    As a result of natural production and contamination of the environment by xenobiotic compounds, halogenated substances are widely distributed in the biosphere. Concern arises as a result of the toxic, carcinogenic, and potential teratogenic nature of these substances. The biotransformations of such halogenated substances are reviewed, with particular emphasis on the biocatalytic cleavage of the carbon-halogen bonds. The physiology, biochemistry,

  1. 8-fluoropurine compounds

    DOEpatents

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

    2001-01-01

    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.

  2. Tagging Classical Sanskrit Compounds

    Microsoft Academic Search

    Brendan S. Gillon

    2009-01-01

    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.

  3. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  4. Compound semiconductor radiation detectors

    NASA Astrophysics Data System (ADS)

    Owens, Alan; Peacock, A.

    2004-09-01

    We discuss the potential benefits of using compound semiconductors for the detection of X- and ?-ray radiation. While Si and Ge have become detection standards for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by one or more of their physical limitations; namely the need for ancillary cooling systems or bulky cryogenics, their modest stopping powers and radiation intolerance. Compound semiconductors encompass such a wide range of physical properties that it is technically feasible to engineer a material to any application. Wide band-gap compounds offer the ability to operate in a wide range of thermal and radiation environments, whilst still maintaining sub-keV spectral resolution at hard X-ray wavelengths. Narrow band-gap materials, on the other hand, offer the potential of exceeding the spectral resolution of both Si and Ge, by as much as a factor of 3. Assuming that the total system noise can be reduced to a level commensurate with Fano noise, spectroscopic detectors could work in the XUV, effectively bridging the gap between the ultraviolet and soft X-ray wavebands. Thus, in principle, compound semiconductor detectors can provide continuous spectroscopic coverage from the far infrared through to ?-ray wavelengths. However, while they are routinely used at infrared and optical wavelengths, in other bands, their development has been plagued by material and fabrication problems. This is particularly true at hard X- and ?-ray wavelengths, where only a few compounds (e.g., GaAs, CdZnTe and HgI2) have evolved sufficiently to produce working detection systems. In this paper, we examine the current status of research in compound semiconductors and by a careful examination of material properties and future requirements, recommend a number of compounds for further development. In the longer term, when material problems are sufficiently under control, we believe the future lies in the development of heterostructures and inserted interface layers to overcome contacting problems and quantum heterostructures and superlattices to facilitate low-noise readout.

  5. Seasonal variability in anthropogenic halocarbon emissions.

    PubMed

    Gentner, Drew R; Miller, Angela M; Goldstein, Allen H

    2010-07-15

    Ambient concentrations of eight predominantly anthropogenic halocarbons were measured via in situ gas chromatography in California's South Coast air basin for both summer and fall during the 2005 Study of Organic Aerosols at Riverside (SOAR). Ongoing emissions of the banned halocarbons methylchloroform and CFC-11 were observed in the South Coast air basin, whereas CFC-113 emissions have effectively ceased. We estimate anthropogenic emissions in the South Coast air basin for methylchloroform, CFC-11, HCFC-141b, chloroform, tetrachloroethene (PCE), trichloroethylene (TCE), and dichloromethane based on regressions of halocarbon to carbon monoxide mixing ratios and carbon monoxide emission inventories. We estimate per capita methylchloroform and chloroform emissions in the South Coast air basin for the year 2005 to be 6.6 +/- 0.4 g/(person.year) and 19 +/- 1 g/(person.year), respectively. We compare our results to national emission estimates calculated from previous work; for several compounds, emissions in the South Coast air basin are significantly lower than national per capita emissions. We observed strong seasonal differences in anthropogenic emissions of methylchloroform and chloroform; emissions were 4.5 and 2.5 times greater in summer than in fall, respectively. Possible seasonal sources include landfills and water chlorination. We conclude that seasonal variability in methylchloroform emissions has not been included in previous inventories and may cause errors in methylchloroform emission estimates after the year 2000 and seasonally resolved inversion calculations of hydroxyl radical abundance. PMID:20536226

  6. Sulfur emissions from Mt. Etna

    Microsoft Academic Search

    Wolfgang Jaeschke; Harald Berresheim; Hans-W. Georgii

    1982-01-01

    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

  7. Identification and quantification of volatile organic compounds from a dairy

    NASA Astrophysics Data System (ADS)

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

    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.

  8. Biologically produced volatile compounds: N2O emissions from soils

    NASA Technical Reports Server (NTRS)

    Banin, A.

    1985-01-01

    Tropospheric nitrous concentration has increased by 0.2 0.4% per year over the period 1975 to 1982, amounting to net addition to the atmosphere of 2.8 - 5.6 Tg N2O-N per year. This perturbation, if continued into the future, will affect stratospheric chemical cycles, and the thermal balance of the Earth. In turn it will have direct and indirect global effects on the biosphere. Though the budget and cycles of N2O on Earth are not yet fully resolved, accumulating information and recent modelling efforts permit a more complete evaluation and better definition of gaps in our knowledge.

  9. Volatile organic compound emissions from Larrea tridentata (creosotebush)

    E-print Network

    Meskhidze, Nicholas

    of the interference of dimethyl sulfide PTR-MS concentration measurements by the hydrated acetaldehyde ion 3 of potential interference of acetaldehyde water clusters on the PTR-MS signal (m/z 63) for dimethyl sulfide. 1:acetaldehyde, m/z 47:ethanol, m/z 61:acetic acid) (Karl et al., 2004; Harley et al., 2007; Jardine et al., 2008

  10. Oral compound nevus.

    PubMed

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

    2014-02-01

    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

  11. Hydrogen in compound semiconductors

    SciTech Connect

    Haller, E.E.

    1993-05-01

    Progress in the understanding of hydrogen and its interactions in III/V and II/VI compound semiconductors is reviewed. Donor, acceptor and deep level passivation is well established in III/V compounds based on electrical measurements and on spectroscopic studies. The hydrogen donor levels in GaAs and GaP are estimated to lie near E{sub v}+0.5 eV and E{sub v}+0.3 eV, respectively. Arsenic acceptors have been passivated by hydrogen in CdTe and the very first nitrogen-hydrogen local vibrational model spectra in ZnSe have been reported. This long awaited result may lead to an explanation for the poor activation of nitrogen acceptors in ZnSe grown by techniques which involve high concentrations of hydrogen.

  12. Arsonium compounds in algae

    PubMed Central

    Benson, A. A.

    1989-01-01

    Search for a precursor of the arsenobetaine discovered in Western Australian rock lobster tail muscle has led to an algal metabolite of radioarsenate having the properties of a trimethylarsoniumriboside derivative of the major arsenicals of aquatic plants, dimethylarsinoylribosylglycerol, its sulfate ester, and the corresponding riboside of phosphatidylglycerol. Such an arsonium compound could serve as metabolic precursor of arsenobetaine, the innocuous arsenical component of many marine food products. The oceanic diatom, Chaetoceros gracilis, cultured in radioarsenate produced a compound whose chemical, chromatographic, and electrophoretic properties are described. It was found to be identical to the trimethylarsonium derivative synthesized from the major algal arsenical, 1-(5?-dimethylarsinoyl-5?-deoxyribosyl)glycerol-3-O -sulfate. PMID:16594059

  13. Arsonium compounds in algae.

    PubMed

    Benson, A A

    1989-08-01

    Search for a precursor of the arsenobetaine discovered in Western Australian rock lobster tail muscle has led to an algal metabolite of radioarsenate having the properties of a trimethylarsoniumriboside derivative of the major arsenicals of aquatic plants, dimethylarsinoylribosylglycerol, its sulfate ester, and the corresponding riboside of phosphatidylglycerol. Such an arsonium compound could serve as metabolic precursor of arsenobetaine, the innocuous arsenical component of many marine food products. The oceanic diatom, Chaetoceros gracilis, cultured in radioarsenate produced a compound whose chemical, chromatographic, and electrophoretic properties are described. It was found to be identical to the trimethylarsonium derivative synthesized from the major algal arsenical, 1-(5'-dimethylarsinoyl-5'-deoxyribosyl)glycerol-3-O -sulfate. PMID:16594059

  14. Multicylinder compound engine

    SciTech Connect

    Paul, M.A.; Paul, A.

    1990-10-23

    This patent describes a compound, rotary-reciprocal engine. It comprises: a two-cycle reciprocator having cylinders, each cylinder having at least one piston arranged for reciprocation in the cylinder in a cycled operation with a timed air input to the cylinder and a timed exhaust from the cylinder; a compressed air intake and combustion gas exit in each cylinder of the reciprocator; fuel injection means for injecting fuel into the cylinders at appropriate times in the cycled operation; and, a rotocharger.

  15. Compound Interdependences in MOP

    Microsoft Academic Search

    Christer Carlsson; Robert Fuller

    1996-01-01

    We consider multiple objective programming (MOP) problems with compound interdependences, i.e. the case when the states of some chosen objective are attained through supportive or inhibitory feed-backs from several other objectives. MOP problems with independent objectives (i.e. when the cause-effect relations between the decision variables and the objectives are completely known) will be treated as special cases of the MOP

  16. Immunomodulating compounds in Basidiomycetes.

    PubMed

    Mizuno, Masashi; Nishitani, Yosuke

    2013-05-01

    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

  17. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1986-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burned for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  18. Compound chondrules fused cold

    NASA Astrophysics Data System (ADS)

    Hubbard, Alexander

    2015-07-01

    About 4-5% of chondrules are compound: two separate chondrules stuck together. This is commonly believed to be the result of the two component chondrules having collided shortly after forming, while still molten. This allows high velocity impacts to result in sticking. However, at T ? 1100 K, the temperature below which chondrules collide as solids (and hence usually bounce), coalescence times for droplets of appropriate composition are measured in tens of seconds. Even at 1025 K, at which temperature theory predicts that the chondrules must have collided extremely slowly to have stuck together, the coalescence time scale is still less than an hour. These coalescence time scales are too short for the collision of molten chondrules to explain the observed frequency of compound chondrules. We suggest instead a scenario where chondrules stuck together in slow collisions while fully solid; and the resulting chondrule pair was subsequently briefly heated to a temperature in the range of 900-1025 K. In that temperature window the coalescence time is finite but long, covering a span of hours to a decade. This is particularly interesting because those temperatures are precisely the critical window for thermally ionized MRI activity, so compound chondrules provide a possible probe into that vital regime.

  19. Toxic compounds in honey.

    PubMed

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

    2014-07-01

    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

  20. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1987-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burn for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  1. Mitigating enteric methane emissions: Where are the biggest opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many opportunities exist to reduce enteric methane emissions per unit of product from ruminant livestock. These include alterations in feeding management and nutrition, addition of compounds to modify rumen function, genetic improvements to increase animal lifetime productivity (including health and...

  2. A Novel New Approach to VOC and HAP Emission Control 

    E-print Network

    McGinness, M.

    2000-01-01

    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...

  3. Study of building material emissions and indoor air quality

    E-print Network

    Yang, Xudong, 1966-

    1999-01-01

    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 ...

  4. 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...

  5. 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...

  6. 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...

  7. 40 CFR 60.613 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Performance for Volatile Organic Compound (VOC) Emissions From the Synthetic Organic Chemical Manufacturing Industry (SOCMI) Air Oxidation Unit Processes § 60.613 Monitoring...installed in the vent stream from each air oxidation reactor within an affected facility...

  8. 40 CFR 60.613 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Performance for Volatile Organic Compound (VOC) Emissions From the Synthetic Organic Chemical Manufacturing Industry (SOCMI) Air Oxidation Unit Processes § 60.613 Monitoring...installed in the vent stream from each air oxidation reactor within an affected facility...

  9. 40 CFR 60.613 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Performance for Volatile Organic Compound (VOC) Emissions From the Synthetic Organic Chemical Manufacturing Industry (SOCMI) Air Oxidation Unit Processes § 60.613 Monitoring...installed in the vent stream from each air oxidation reactor within an affected facility...

  10. 40 CFR 60.613 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Performance for Volatile Organic Compound (VOC) Emissions From the Synthetic Organic Chemical Manufacturing Industry (SOCMI) Air Oxidation Unit Processes § 60.613 Monitoring...installed in the vent stream from each air oxidation reactor within an affected facility...

  11. 40 CFR 60.613 - Monitoring of emissions and operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Performance for Volatile Organic Compound (VOC) Emissions From the Synthetic Organic Chemical Manufacturing Industry (SOCMI) Air Oxidation Unit Processes § 60.613 Monitoring...installed in the vent stream from each air oxidation reactor within an affected facility...

  12. Bilingual reading of compound words.

    PubMed

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-02-01

    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

  13. Complex Compound Chemical Heat Pumps

    E-print Network

    Rockenfeller, U.; Langeliers, J.; Horn, G.

    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...

  14. Special Risks of Pharmacy Compounding

    MedlinePLUS

    ... Consumer Updates RSS Feed The Special Risks of Pharmacy Compounding Search the Consumer Updates Section Get Consumer ... page: A Troubling Trend What You Can Do Pharmacy compounding is a practice in which a licensed ...

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

    Microsoft Academic Search

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

    2001-01-01

    Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10–1300?molm?2s?1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7%

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

    PubMed

    Ho, K F; Lee, S C

    2002-04-22

    Volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds are the major organic pollutants in the atmosphere. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan area of Hong Kong. A 12-month monitoring program for VOCs, PAHs and carbonyl compounds was performed at a roadside urban station at Hong Kong Polytechnic University (HKPU) in order to determine the correlations of each selected pollutant. The monitoring program ran from 16 April 1999 to 10 April 2000 for a period of 1 year, and a 2-week winter intensive sampling was carried out during January 2000. Traditionally, emission sources are identified from organic compounds in air particulates. Since many of the gaseous and particulate phases of organic compounds are from the same sources, correlations between the major exhausts are to be expected. Therefore, it would be more effective to apportion the sources using the combined gaseous and particulate phases of organic compounds. Correlations of selected pollutants within two other toxic air pollutants (TAPs) monitoring stations in Tsuen Wan (TW) and Central/Western (CW) were analyzed. Good correlations were found between pollutants that came from vehicle exhaust, especially in intensive sampling periods at HKPU roadside station. This was because the washing out effect for particulates during rainy days and photochemical degradation during high solar radiation were minimized in wintertime. PMID:12049391

  17. 40 CFR 60.312 - Standard for volatile organic compounds (VOC).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Standard for volatile organic compounds (VOC). 60.312 Section 60.312 Protection...Standard for volatile organic compounds (VOC). (a) On and after the date on...cause the discharge into the atmosphere of VOC emissions from any metal furniture...

  18. Phenolic compounds in Catharanthus roseus

    Microsoft Academic Search

    Natali Rianika Mustafa; Robert Verpoorte

    2007-01-01

    Besides alkaloids Catharanthus roseus produces a wide spectrum of phenolic compounds, this includes C6C1 compounds such as 2,3-dihydoxybenzoic acid, as well as\\u000a phenylpropanoids such as cinnamic acid derivatives, flavonoids and anthocyanins. The occurrence of these compounds in C. roseus is reviewed as well as their biosynthesis and the regulation of the pathways. Both types of compounds compete with the indole

  19. Study of the impact of cruise and passenger ships on a Mediterranean port city air quality - Study of future emission mitigation scenarios

    NASA Astrophysics Data System (ADS)

    Liora, Natalia; Poupkou, Anastasia; Kontos, Serafim; Giannaros, Christos; Melas, Dimitrios

    2015-04-01

    An increase of the passenger ships traffic is expected in the Mediterranean Sea as targeted by the EU Blue Growth initiative. This increase is expected to impact the Mediterranean port-cities air quality considering not only the conventional atmospheric pollutants but also the toxic ones that are emitted by the ships (e.g. Nickel). The aim of this study is the estimation of the present and future time pollutant emissions from cruise and passenger maritime transport in the port area of Thessaloniki (Greece) as well as the impact of those emissions on the city air quality. Cruise and passenger ship emissions have been estimated for the year 2013 over a 100m spatial resolution grid which covers the greater port area of Thessaloniki. Emissions have been estimated for the following macro-pollutants; NOx, SO2, NMVOC, CO, CO2 and particulate matter (PM). In addition, the most important micro-pollutants studied in this work are As, Cd, Pb, Ni and Benzo(a)pyrene for which air quality limits have been set by the EU. Emissions have been estimated for three operation modes; cruising, maneuvering and hotelling. For the calculation of the present time maritime emissions, the activity data used were provided by the Thessaloniki Port Authority S.A. Moreover, future pollutant emissions are estimated using the future activity data provided by the Port Authority and the IMO legislation for shipping in the future. In addition, two mitigation emission scenarios are examined; the use of Liquefied Natural Gas (LNG) as a fuel used by ships and the implementation of cold ironing which is the electrification of ships during hotelling mode leading to the elimination of the corresponding emissions. The impact of the present and future passenger ship emissions on the air quality of Thessaloniki is examined with the use of the model CALPUFF applied over the 100m spatial resolution grid using the meteorology of WRF. Simulations of the modeling system are performed for four different emission scenarios; present time scenario, future time scenario, future time scenario plus use of LNG and future time scenario plus use of cold ironing. The differences in pollutant levels between the scenarios examined are presented and discussed

  20. Carcinogenic effect of nickel compounds

    Microsoft Academic Search

    Haitian Lu; Xianglin Shi; Max Costa; Chuanshu Huang

    2005-01-01

    Nickel is a widely distributed metal that is industrially applied in many forms. Accumulated epidemiological evidence confirms that exposures to nickel compounds are associated with increased nasal and lung cancer incidence, both in mostly occupational exposures. Although the molecular mechanisms by which nickel compounds cause cancer are still under intense investigation, the carcinogenic actions of nickel compounds are thought to

  1. Organometallic chemistry of bimetallic compounds

    SciTech Connect

    Casey, C.P.

    1991-07-01

    This report consists of six sections: heterobimetallic dihydrides, early-late transition metal heterobimetallic compounds, amphiphilic carbene complexes and hydroxycarbene complexes, diiron compounds with bridging hydrocarbon ligands, diphosphine chelates with natural bite angles near 120 degrees, and synthesis and reactions of M=M compounds. (WET)

  2. Emission Spectrometry.

    ERIC Educational Resources Information Center

    Keliher, Peter N.; And Others

    1984-01-01

    Presented is a review of selected literature on emission spectrometry published during 1982 and 1983. The review is organized under these headings: books and reviews; spectral descriptions and classifications; instrumentation; standards, samples, nomenclature, calibration, calculations; excitation sources; selected applications; and meetings. (JN)

  3. Emissions Overview

    NASA Technical Reports Server (NTRS)

    Rohde, John

    2001-01-01

    The Emissions Reduction Project is working in close partnership with the U.S. aircraft engine manufacturers and academia to develop technologies to reduce NO, emissions by 70 percent over the LTO cycle from 1996 ICAO standards with no increase in other emission constituents (carbon monoxide, smoke, and unburned hydrocarbons) and with comparable NO, reduction during cruise operations. These technologies cannot impact the overall combustor and fuel delivery system operability, affordability or maintainability. These new combustion concepts and technologies will include lean burning combustors with higher operating gas temperatures and pressures, fuel staging, ceramic matrix composite material liners with reduced cooling air and possibly advanced controls. Improved physics-based analysis tool will be developed and validated and some longer term technologies that are more revolutionary will be assessed. These improved computational codes will provide improved design tools to increase design confidence and cut the development time to achieve major reductions in NO, emissions. Longer term, revolutionary technologies like active combustion controls, combustion from a large array of micro-injectors, electrostatic fuel injectors, fuel additives and others will be investigated and assessed through proof-of-concept testing.

  4. Potential risks of pharmacy compounding.

    PubMed

    Gudeman, Jennifer; Jozwiakowski, Michael; Chollet, John; Randell, Michael

    2013-03-01

    Pharmacy compounding involves the preparation of customized medications that are not commercially available for individual patients with specialized medical needs. Traditional pharmacy compounding is appropriate when done on a small scale by pharmacists who prepare the medication based on an individual prescription. However, the regulatory oversight of pharmacy compounding is significantly less rigorous than that required for Food and Drug Administration (FDA)-approved drugs; as such, compounded drugs may pose additional risks to patients. FDA-approved drugs are made and tested in accordance with good manufacturing practice regulations (GMPs), which are federal statutes that govern the production and testing of pharmaceutical products. In contrast, compounded drugs are exempt from GMPs, and testing to assess product quality is inconsistent. Unlike FDA-approved drugs, pharmacy-compounded products are not clinically evaluated for safety or efficacy. In addition, compounded preparations do not have standard product labeling or prescribing information with instructions for safe use. Compounding pharmacies are not required to report adverse events to the FDA, which is mandatory for manufacturers of FDA-regulated medications. Some pharmacies engage in activities that extend beyond the boundaries of traditional pharmacy compounding, such as large-scale production of compounded medications without individual patient prescriptions, compounding drugs that have not been approved for use in the US, and creating copies of FDA-approved drugs. Compounding drugs in the absence of GMPs increases the potential for preparation errors. When compounding is performed on a large scale, such errors may adversely affect many patients. Published reports of independent testing by the FDA, state agencies, and others consistently show that compounded drugs fail to meet specifications at a considerably higher rate than FDA-approved drugs. Compounded sterile preparations pose the additional risk of microbial contamination to patients. In the last 11 years, three separate meningitis outbreaks have been traced to purportedly 'sterile' steroid injections contaminated with fungus or bacteria, which were made by compounding pharmacies. The most recent 2012 outbreak has resulted in intense scrutiny of pharmacy compounding practices and increased recognition of the need to ensure that compounding is limited to appropriate circumstances. Patients and healthcare practitioners need to be aware that compounded drugs are not the same as generic drugs, which are approved by the FDA. The risk-benefit ratio of using traditionally compounded medicines is favorable for patients who require specialized medications that are not commercially available, as they would otherwise not have access to suitable treatment. However, if an FDA-approved drug is commercially available, the use of an unapproved compounded drug confers additional risk with no commensurate benefit. PMID:23526368

  5. Offset Compound Gear Drive

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  6. Terpenoid emissions from fully grown East Siberian Larix cajanderi trees

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    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.

  7. Transition Metal Compounds

    NASA Astrophysics Data System (ADS)

    Khomskii, Daniel I.

    2014-10-01

    1. Localised and itinerant electrons in solids; 2. Isolated transition metal ions; 3. Transition metal ions in crystals; 4. Mott–Hubbard vc charge-transfer insulators; 5. Exchange interaction and magnetic structures; 6. Cooperative Jahn–Teller effect and orbital ordering; 7. Charge ordering in transition metal compounds; 8. Ferroelectrics, magnetoelectrics and multiferroics; 9. Doping of correlated systems and correlated metals; 10. Metal-insulator transitions; 11. Kondoeffect, mixed valence and heavy fermions; Appendix A. Some historical notes; Appendix B. A layman's guide to second quantization; Appendix C. Phase transitions and free energy expansion: Landau theory in a nutshell.

  8. Superconductivity in plutonium compounds

    NASA Astrophysics Data System (ADS)

    Sarrao, J. L.; Bauer, E. D.; Mitchell, J. N.; Tobash, P. H.; Thompson, J. D.

    2015-07-01

    Although the family of plutonium-based superconductors is relatively small, consisting of four compounds all of which crystallize in the tetragonal HoCoGa5 structure, these materials serve as an important bridge between the known Ce- and U-based heavy fermion superconductors and the high-temperature cuprate superconductors. Further, the partial localization of 5f electrons that characterizes the novel electronic properties of elemental plutonium appears to be central to the relatively high superconducting transition temperatures that are observed in PuCoGa5, PuRhGa5, PuCoIn5, and PuRhIn5.

  9. Complex fragment emission at low and high excitation energy

    SciTech Connect

    Moretto, L.G.

    1986-08-01

    Complex fragment emission has been certified as a compound nucleus process at low energies. An extension of the measurements to heavy ion reactions up to 50 MeV/u shows that most complex fragments are emitted by highly excited compound nuclei formed in incomplete fusion reactions. 12 refs., 26 figs.

  10. Distribution and emission of chloropicrin applied as gelatin capsules

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chloropicrin (CP) is a potential methyl bromide alternative for controlling soil-borne pests. However, the compound is highly volatile that poses strong exposure risks for humans and the environment because of volatile organic compound (VOC) emissions. A gelatin capsule formulation was developed as...

  11. 59 FR- National Emission Standards for Hazardous Air Pollutants (NESHAP) (Secondary Lead Smelters)

    Federal Register 2010, 2011, 2012, 2013, 2014

    1994-06-09

    ...for lead compounds, total hydrocarbons (THC), and HCl and Cl 2 emissions and opacity...are being proposed for lead compounds and THC as surrogates for metal HAP's and organic... 2. There is no proposed standard for THC emissions from reverberatory,...

  12. Effect of feeding distiller’s grains on reduced sulfur emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Odorous reduced sulfur compounds are produced during manure decomposition and emitted from confined animal feeding operations. Feeding high-sulfur distiller’s byproducts may increase the emission of these compounds. The objectives of a series of feedlot pen studies was to (i) determine if emission...

  13. 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...

  14. Characterizing emissions from a Söderberg aluminum smelter

    NASA Astrophysics Data System (ADS)

    Leber, Bernard P.; Schmeil, Paul F.

    1995-05-01

    This article describes the results of studies conducted to analyze the fine (<10 ?m) particulate matter, the extractable organic matter, and the hydrocarbon compounds emitted from Kaiser's horizontal-stud Söderberg aluminum smelter in Tacoma, Washington. To perform the characterization, samples were taken from representative potroom roof and air-control-system emissions.

  15. 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...

  16. A model for predicting VOC emission from silage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silage has been shown to be an important source of emissions of volatile organic compounds (VOCs), which are precursors to ground-level ozone. Measurements show that environmental conditions and silage properties influence emission rates, making it difficult to assess the contribution of silage to V...

  17. EVALUATION OF MAINTENANCE FOR FUGITIVE VOC EMISSIONS CONTROL

    EPA Science Inventory

    The U.S. EPA Office of Air Quality Planning and Standards (OAQPS) has the responsibility for formulating regulations for the control of fugitive emissions of volatile organic compounds (VOC). 'Fugitive emissions' generally refers to the diffuse release of vaporized hydrocarbon or...

  18. Emissions of volatile aldehydes from heated cooking oils

    Microsoft Academic Search

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

    2010-01-01

    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

  19. Turbo compound engine

    SciTech Connect

    Kawamura, H.

    1988-05-24

    A turbo compound engine having a first exhaust turbine coupled to an exhaust pipe of an internal combustion engine and a second exhaust turbine coupled to an exhaust port of the first exhaust turbine is described comprising: a first generator drivable by the first exhaust turbine; a second generator drivable by the second exhaust turbine; a motor operatively coupled to an output shaft of the internal combustion engine; speed detecting means for detecting the speed of rotation of the internal combustion engine; and control means for controlling the frequency of electric power, which is the sum of electric power outputs from the first and second generators and supplied to the motor, based on a signal from the speed detecting means, in order to control operation of the motor.

  20. Common Compound Library

    NSDL National Science Digital Library

    Frederick A. Senese

    This database, part of a college-level chemistry course, provides information on hundreds of compounds, elements, and substances encountered in introductory chemistry courses and in everyday life. The informaion includes chemical synonyms, molecular weights, structures, equilibrium constants, thermodynamic properties, and common uses, with properties presented in a variety of common units. Structure information includes flat structural formulas, ball and stick models, electron density/electric potential maps, and Chime "live" structures that can be rotated and queried for bond lengths, bond angles, and torsion angles. The site also includes links to the course website, a glossary, a frequently-asked-questions feature, information on sources used in constructing the database, and many other resources.

  1. Dioxin and Related Compounds

    NSDL National Science Digital Library

    1994-01-01

    This substantial new site, provided by the Environmental Protection Agency's National Center for Environmental Assessment, addresses the mechanism of Dioxin contamination and describes NCEA's Dioxin Reassessment efforts. The site provides full descriptions and molecular graphics of "Dioxins and related compounds" (Furans, PCB's), as well as EPA Summaries on Dioxin exposure, Dioxin risk, and dose response. The Dioxin Exposure Initiative seeks to quantitatively link dioxin sources to general population exposures using "source measurements, environmental media and national food surveys, and fate and transport modeling." Further links to EPA Regulations and EPA Analytical Methods round out the site. Note that many of the documents at the site are available in Adobe Acrobat (.pdf) or WordPerfect format.

  2. Organic emissions from coal AFBC

    SciTech Connect

    Mastral, A.M.; Callen, M.S.; Murillo, R.; Garcia, T.

    1999-07-01

    AFBC is considered to be an environmentally favorable combustion technology where control of emissions can be integrated into the combustion system. FBC operates at low temperatures, 800--900 C, to prevent thermal NO formation and to favor the sulfur removal by the sorbent but it has not been taken into account that, when coal is burnt, not only NO{sub x}, SO{sub x} and CO{sub x} are emitted. In addition volatile organic pollutants (VOC) are emitted. From these VOC, the polycyclic aromatic hydrocarbons (PAH) constitute one of the most dangerous compounds due to their possibility of interacting with biological nucleophiles. It is expected that new legislation about the regulation on PAH emissions be very restrictive. In this work, PAH emissions from coal AFBC as a function of the coal combustion variables (combustion temperature, gas flow and percentage of excess oxygen) are reported. In addition, the bed nature on PAH emissions is also assessed. PAH emissions at the standard conditions used at the AFBC power stations are assessed by the study carried out in an AFBC laboratory pilot plant. The PAH listed by US EPA as priority pollutants are analyzed by fluorescence spectroscopy (FS) at the synchronous mode.

  3. Volatile organic compounds (VOCs) emitted from 40 Mediterranean plant species:. VOC speciation and extrapolation to habitat scale

    NASA Astrophysics Data System (ADS)

    Owen, Susan Margaret; Boissard, Christophe; Hewitt, C. Nicholas

    Forty native Mediterranean plant species were screened for emissions of the C5 and C10 hydrocarbons, isoprene and monoterpenes, in five different habitats. A total of 32 compounds were observed in the emissions from these plants. The number of compounds emitted by different plant species varied from 19 ( Quercus ilex) to a single compound emission, usually of isoprene. Emission rates were normalised to generate emission factors for each plant species for each sampling event at standard conditions of temperature and light intensity. Plant species were categorised according to their main emitted compound, the major groups being isoprene, ?-pinene, linalool, and limonene emitters. Estimates of habitat fluxes for each emitted compound were derived from the contributing plant species' emission factors, biomass and ground cover. Emissions of individual compounds ranged from 0.002 to 505 g ha -1 h -1 (camphene from garrigue in Spain in autumn and isoprene from riverside habitats in Spain in late spring; respectively). Emissions of isoprene ranged from 0.3 to 505 g ha -1 h -1 (macchia in Italy in late spring and autumn; and riverside in Spain in late spring; respectively) and ?-pinene emissions ranged from 0.51 to 52.92 g ha -1 h -1 (garrigue in Spain in late spring; and forest in France in autumn; respectively). Habitat fluxes of most compounds in autumn were greater than in late spring, dominated by emissions from Quercus ilex, Genista scorpius and Quercus pubescens. This study contributes to regional emission inventories and will be of use to tropospheric chemical modellers.

  4. Generation of low work function, stable compound thin films by laser ablation

    DOEpatents

    Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

    2001-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  5. Light-Particle Emission from Fissioning Hot Rotating Nuclei

    NASA Astrophysics Data System (ADS)

    Bartel, Johann; Pomorski, Krzysztof; Nerlo-Pomorska, Bo?ena

    2012-05-01

    The decay process of hot and rotating compound nuclei is studied. In particular the competition between fission and n, p and ?-particle emission is discussed. The nuclear fission process is described by a Langevin equation coupled to Master equations for particle evaporation. Light particle emission rates obtained with the Weisskopf theory and the semiclassical phase-space distribution-function approach are compared. Coulomb barriers for the emission of charged particles are studied.

  6. Biogenic emissions in Europe. 1. Estimates and uncertainties

    Microsoft Academic Search

    David Simpson; Alex Guenther; C. Nicholas Hewitt; Rainer Steinbrecher

    1995-01-01

    Several biogenic volatile organic compound (VOC) emission algorithms have been used, together with meteorological data from the EMEP MSC-W ozone model, to generate estimates of the emissions of isoprene from European forests and agricultural crops over several summer periods. The most up-to-date estimate combines the recently updated isoprene emission factors from the United States with available knowledge of European tree

  7. Emission of methyl bromide from biomass burning

    SciTech Connect

    Manoe, S.; Andreae, M.O. (Max Planck Institute for Chemistry, Mainz (Germany))

    1994-03-04

    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.

  8. Isoprene emission from tropical tree species.

    PubMed

    Padhy, P K; Varshney, C K

    2005-05-01

    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

  9. Volatile Organic Compound Analysis in Istanbul

    NASA Astrophysics Data System (ADS)

    ?apraz, Ö.; Deniz, A.; Öztürk, A.; Incecik, S.; Toros, H.; Co?kun, M.

    2012-04-01

    Volatile Organic Compound Analysis in Istanbul Ö. Çapraz1, A. Deniz1,3, A. Ozturk2, S. Incecik1, H. Toros1 and, M. Coskun1 (1) Istanbul Technical University, Faculty of Aeronautics and Astronautics, Department of Meteorology, 34469, Maslak, Istanbul, Turkey. (2) Istanbul Technical University, Faculty of Chemical and Metallurgical, Chemical Engineering, 34469, Maslak, Istanbul, Turkey. (3) Marmara Clean Air Center, Ministry of Environment and Urbanization, Ni?anta??, 34365, ?stanbul, Turkey. One of the major problems of megacities is air pollution. Therefore, investigations of air quality are increasing and supported by many institutions in recent years. Air pollution in Istanbul contains many components that originate from a wide range of industrial, heating, motor vehicle, and natural emissions sources. VOC, originating mainly from automobile exhaust, secondhand smoke and building materials, are one of these compounds containing some thousands of chemicals. In spite of the risks to human health, relatively little is known about the levels of VOC in Istanbul. In this study, ambient air quality measurements of 32 VOCs including hydrocarbons, halogenated hydrocarbons and carbonyls were conducted in Ka??thane (Golden Horn) region in Istanbul during the winter season of 2011 in order to develop the necessary scientific framework for the subsequent developments. Ka??thane creek valley is the source part of the Golden Horn and one of the most polluted locations in Istanbul due to its topographical form and pollutant sources in the region. In this valley, horizontal and vertical atmospheric motions are very weak. The target compounds most commonly found were benzene, toluene, xylene and ethyl benzene. Concentrations of total hydrocarbons ranged between 1.0 and 10.0 parts per billion, by volume (ppbv). Ambient air levels of halogenated hydrocarbons appeared to exhibit unique spatial variations and no single factor seemed to explain trends for this group of compounds. N-octane, 3-methylheptane, n-nonane, 2,3,4-trimethylpentane and n-hexane parameters ranged between 3 ppbv and maximum value of 10 ppbv. The other VOC parameters are measured below 3 ppbv value. At participating urban locations for the year of data considered, levels of carbonyls were higher than the level of the other organic compound groups, suggesting that emissions from motor vehicles and photochemical reactions strongly in?uence ambient air concentrations of carbonyls. Of the most prevalent carbonyls, formaldehyde and acetaldehyde were the dominant compounds, ranging from 1.5-7.4 ppbv for formaldehyde, to 0.8-2.7 ppbv for acetaldehyde. Keywords: Air quality, Volatile Organic Compounds (VOC), industry, meteorology, urban, Ka??thane, ?stanbul. Acknowledgment: This work was part of the TUJJB-TUMEHAP-01-10 and Turkish Scientific and Technical Research Council Project No: 109Y132.

  10. Junction-based field emission structure for field emission display

    DOEpatents

    Dinh, Long N. (Concord, CA); Balooch, Mehdi (Berkeley, CA); McLean, II, William (Oakland, CA); Schildbach, Marcus A. (Livermore, CA)

    2002-01-01

    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.

  11. TSTA compound cryopump

    SciTech Connect

    Batzer, T.H.; Patrick, R.E.; Call, W.R.

    1980-08-18

    The Tritium System Test Assembly (TSTA), at the Los Alamos Scientific Laboratory, is intended to demonstrate realistic fuel supply and cleanup scenarios for future fusion reactors. The vacuum pumps must be capable of handling large quantities of reactor exhaust gases consisting largely of mixtures of hydrogen and helium isotopes. Cryocondensing pumps will not pump helium at 4.2 K; while cryosorption pumps using molecular sieves or charcoal have good helium pumping speed, the adsorbent clogs with condensed hydrogen while pumping mixtures of both. A solution to this problem is a compound design whereby the first stage condenses the hydrogen and the second, or sorption, stage pumps the helium. The TSTA pump designed at Lawrence Livermore National Laboratory uses argon gas to cryotrap the helium in the helium-hydrogen mixture. The argon is sprayed directly onto the 4.2 K surface at a rate proportional to the helium flow rate, permitting continuous pumping of the helium-hydrogen mixtures in a single-stage pump. However, the possibility of differential desorption as a first stage in the TSTA gas separation cycle required the inclusion of a first-stage hydrogen isotope condenser. The design, performance, and operating characteristics are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  13. [Estimation and forecast of volatile organic compounds emitted from paint uses in China].

    PubMed

    Wei, Wei; Wang, Shu-xiao; Hao, Ji-ming

    2009-10-15

    Based on the current consumptions and forecast consumptions of paints in China, using the volatile organic compounds (VOC) contents of paints calculated as emission factors, an emission inventory model was established to calculate provincial, sector-specific, and species-specific VOC emissions during 2005-2020. The results indicated that the VOC amount emitted from paint use was 1883 kt in 2005, of which aromatics, alcohol compounds, ester compounds, ether compounds and ketone compounds were the main species. The maximum incremental reactivity (MIR,O3/VOC) of VOC emitted in 2005 was about 3.6 g/kg, and the toxic VOC accounted for 31% of the total in weight. The VOC emissions would increase to 5673 kt in 2020 if there were no further control policies and actions taken. Therefore, it is essential to implement the VOC emission control from paint uses as soon as possible. Two control scenarios were developed to evaluate the potential of VOC emission reductions. In 2020, VOC emissions from paint uses might be controlled at 3 519 kt through the improvement of paints quality to the level of that in developed countries in 1990s and installation of waste gas treatment equipments in newly-built factories. VOC emissions could be further reduced to 2243 kt if the quality of decorative paint and wood paint would be improved to the current level of that in developed countries and all factories install waste gas treatment equipments. All these control measures also helpe to reduce the toxicity and atmospheric oxidation reactivity of VOC emissions. PMID:19968091

  14. Page 1 of 6 Consideration of the Change of Material Emission Signatures due to Long-

    E-print Network

    Hansen, René Rydhof

    compounds with great potency to human health and perception, and their chemical measurements were reportedPage 1 of 6 Consideration of the Change of Material Emission Signatures due to Long- term Emissions to characterize the changes of VOC material emission profiles over time and develop a method to account

  15. Global simulation of aromatic volatile organic compounds in the atmosphere

    NASA Astrophysics Data System (ADS)

    Cabrera Perez, David; Taraborrelli, Domenico; Pozzer, Andrea

    2015-04-01

    Among the large number of chemical compounds in the atmosphere, the organic group plays a key role in the tropospheric chemistry. Specifically the subgroup called aromatics is of great interest. Aromatics are the predominant trace gases in urban areas due to high emissions, primarily by vehicle exhausts and fuel evaporation. They are also present in areas where biofuel is used (i.e residential wood burning). Emissions of aromatic compounds are a substantial fraction of the total emissions of the volatile organic compounds (VOC). Impact of aromatics on human health is very important, as they do not only contribute to the ozone formation in the urban environment, but they are also highly toxic themselves, especially in the case of benzene which is able to trigger a range of illness under long exposure, and of nitro-phenols which cause detrimental for humans and vegetation even at very low concentrations. The aim of this work is to assess the atmospheric impacts of aromatic compounds on the global scale. The main goals are: lifetime and budget estimation, mixing ratios distribution, net effect on ozone production and OH loss for the most emitted aromatic compounds (benzene, toluene, xylenes, ethylbenzene, styrene and trimethylbenzenes). For this purpose, we use the numerical chemistry and climate simulation ECHAM/MESSy Atmospheric Chemistry (EMAC) model to build the global atmospheric budget for the most emitted and predominant aromatic compounds in the atmosphere. A set of emissions was prepared in order to include biomass burning, vegetation and anthropogenic sources of aromatics into the model. A chemical mechanism based on the Master Chemical Mechanism (MCM) was developed to describe the chemical oxidation in the gas phase of these aromatic compounds. MCM have been reduced in terms of number of chemical equation and species in order to make it affordable in a 3D model. Additionally other features have been added, for instance the production of HONO via ortho-nitrophenols photolysis. The model results are compared with observations from different surface and aircraft campaigns in order to estimate the accuracy of the model.

  16. Bilingual Reading of Compound Words

    ERIC Educational Resources Information Center

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-01-01

    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…

  17. ATMOSPHERIC FREONS AND HALOGENATED COMPOUNDS

    EPA Science Inventory

    Ambient levels of atmospheric Freons, halogenated hydrocarbons, and SF6 were measured at various locations in the U.S.A. Compounds such as CCl3F, CCl2F2, CH3-CCl3, and CCl4 were ubiquitious and generally measured at sub ppb levels. Tropospherically reactive compounds such as C2Cl...

  18. Antifungal Compounds from Piper Species

    PubMed Central

    Xu, Wen-Hui; Li, Xing-Cong

    2013-01-01

    This review documents chemical structures and antifungal activities of 68 compounds isolated from 22 Piper species of the plant family Piperaceae. These compounds include amides, flavonoids, prenylated benzoic acid derivatives, lignans, phenylpropanoids, butenolides, and cyclopentendiones. Some of them may serve as leads for potential pharmaceutical or agricultural fungicide development. PMID:24307889

  19. Video: Focusing a Compound Microscope

    NSDL National Science Digital Library

    This video from CUNY Kingsborough Community College describes how to focus a compound microscope. The brief clip, available for viewing on YouTube, would be most useful for students with a basic understanding of the parts of a compound microscope and how to use it. Running time for the video is 0:55.

  20. Butyltin Compounds in Human Liver

    Microsoft Academic Search

    Jesper B. Nielsen; Jakob Strand

    2002-01-01

    Intake of marine food is the main source of butyltin exposure in humans. Health effects following exposure to butyltin compounds are usually in the immune system, but endocrine effects of butyltin from a variety of marine species have been documented. The information on human exposure to butyltin compounds and hepatic deposition is limited. The present study include 18 consecutively sampled

  1. Macrocyclic Compounds as Corrosion Inhibitors

    Microsoft Academic Search

    M. A. Quraishi; J. A. Rawat; M. A. Ajmal

    1998-01-01

    The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature,

  2. Anaerobic Metabolism of Aromatic Compounds

    Microsoft Academic Search

    GEORG FUCHS

    2008-01-01

    Aromatic compounds comprise a wide variety of natural and synthetic compounds that can serve as substrates for bacterial growth. So far, four types of aromatic metabolism are known. (1) The aerobic aromatic metabolism is characterized by the extensive use of molecular oxygen as co- substrate for oxygenases that introduce hydroxyl groups and cleave the aromatic ring. (2) In the presence

  3. Devices for collecting chemical compounds

    DOEpatents

    Scott, Jill R; Groenewold, Gary S

    2013-12-24

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  4. Antimicrobial Compounds in Tears

    PubMed Central

    McDermott, Alison M.

    2013-01-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. PMID:23880529

  5. Radiative Forcing from Carbonaceous Emissions

    NASA Astrophysics Data System (ADS)

    Fatima, H.; Sharma, O.; Upadhyaya, H.

    2011-12-01

    Black Carbon particles are emitted as primary particles from incomplete combustion process, such as fossil fuel and biomass burning. Organic carbon particles are released in the atmosphere both from primary emissions and secondary emission of gaseous compounds via condensation or gas phase oxidation of hydrocarbons. Black carbon aerosols absorb the solar radiation and induce positive forcing whereas organic matter aerosols reflect solar radiation and produce negative forcing. Direct radiative forcing at the top of the atmosphere (TOA) for black carbon aerosols from these two inventories comes out to be +0.33 W/m2 (GEIA) and +0.14 W/m2 (Bond et al. 2004) respectively. However, for organic matter aerosols, it is simulated as -0.44 W/m2 for GEIA and -0.11 W/m2 with the inventory of Bond et al. (2004). In the present study we have compared the annual global burden, aerosol optical depth (AOD) and direct radiative forcing of carbonaceous aerosols using two emission inventories with the help of the general circulation model of the Laboratoire de Météorologie Dynamique (LMD). Normalised difference plots clearly show that with GEIA inventory model simulates generally higher values carbonaceous aerosols which are far superior in some parts of the globe in comparison to the BOND emission inventory.

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

    NASA Astrophysics Data System (ADS)

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

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

  7. Governing processes for reactive nitrogen compounds in the European atmosphere

    NASA Astrophysics Data System (ADS)

    Hertel, O.; Skjøth, C. A.; Reis, S.; Bleeker, A.; Harrison, R. M.; Cape, J. N.; Fowler, D.; Skiba, U.; Simpson, D.; Jickells, T.; Kulmala, M.; Gyldenkærne, S.; Sørensen, L. L.; Erisman, J. W.; Sutton, M. A.

    2012-12-01

    Reactive nitrogen (Nr) compounds have different fates in the atmosphere due to differences in the governing processes of physical transport, deposition and chemical transformation. Nr compounds addressed here include reduced nitrogen (NHx: ammonia (NH3) and its reaction product ammonium (NH4+)), oxidized nitrogen (NOy: nitrogen monoxide (NO) + nitrogen dioxide (NO2) and their reaction products) as well as organic nitrogen compounds (organic N). Pollution abatement strategies need to take into account the differences in the governing processes of these compounds when assessing their impact on ecosystem services, biodiversity, human health and climate. NOx (NO + NO2) emitted from traffic affects human health in urban areas where the presence of buildings increases the residence time in streets. In urban areas this leads to enhanced exposure of the population to NOx concentrations. NOx emissions generally have little impact on nearby ecosystems because of the small dry deposition rates of NOx. These compounds need to be converted into nitric acid (HNO3) before removal through deposition is efficient. HNO3 sticks quickly to any surface and is thereby either dry deposited or incorporated into aerosols as nitrate (NO3-). In contrast to NOx compounds, NH3 has potentially high impacts on ecosystems near the main agricultural sources of NH3 because of its large ground-level concentrations along with large dry deposition rates. Aerosol phase NH4+ and NO3- contribute significantly to background PM2.5 and PM10 (mass of aerosols with an aerodynamic diameter of less than 2.5 and 10 ?m, respectively) with an impact on radiation balance as well as potentially on human health. Little is known quantitatively and qualitatively about organic N in the atmosphere, other than that it contributes a significant fraction of wet-deposited N, and is present in both gaseous and particulate forms. Further studies are needed to characterise the sources, air chemistry and removal rates of organic N emissions.

  8. Emission characteristics of VOCs from athletic tracks.

    PubMed

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

    1999-12-23

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

  9. Membrane rejection of nitrogen compounds

    NASA Technical Reports Server (NTRS)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

  10. [Synthesis of new blue pyrazoline fluorescent compounds and study of infrared spectroscopy].

    PubMed

    Xian, Yuan-Fang; Li, Dong-Feng; Wang, Yu-Ming

    2008-07-01

    According to Schellhammer theory of the relation between chemical structure and fluorescent quality, and referring to the synthesized benzothiazolyl pyrazoline compounds, the authors designed 1-benzimidazolyl or 1-benzothiazolyl, 3-phenylic derivatives, which posses fluorescent property. The authors introduced 5-phenyl as auxochrome group which can make fluorescence spectrum bathochromic. If there were -NH2 in the benzene ring, the fluorescence would be increased. Two kinds of benzimidazolyl and benzothiazolyl compounds with -NH2 were synthesized which were not reported. The determination of fluorescence proved that its fluorescence strength is better. The fluorescence emission wavelength is in the region of green-blue light, and there are two kinds of blue light fluorescence compounds. All these compounds were characterized by elemental analysis and infrared spectroscopy. The characteristic peaks of the absorption spectra of these compounds were found by IR spectral analysis. The compound structure was determined. PMID:18844173

  11. Switchable sensitizers stepwise lighting up lanthanide emissions

    PubMed Central

    Zhang, Yan; Jiao, Peng-Chong; Xu, Hai-Bing; Tang, Ming-Jing; Yang, Xiao-Ping; Huang, Shaoming; Deng, Jian-Guo

    2015-01-01

    Analagous to a long-ranged rocket equipped with multi-stage engines, a luminescent compound with consistent emission signals across a large range of concentrations from two stages of sensitizers can be designed. In this approach, ACQ, aggregation-caused quenching effect of sensitizers, would stimulate lanthanide emission below 10?4?M, and then at concentrations higher than 10?3?M, the “aggregation-induced emission” (AIE) effect of luminophores would be activated with the next set of sensitizers for lanthanide emission. Simultaneously, the concentration of the molecules could be monitored digitally by the maximal excitation wavelengths, due to the good linear relationship between the maximal excitation wavelengths and the concentrations {lg(M)}. This model, wherein molecules are assembled with two stages (both AIE and ACQ effect) of sensitizers, may provide a practicable strategy for design and construction of smart lanthanide bioprobes, which are suitable in complicated bioassay systems in which concentration is variable. PMID:25791467

  12. Switchable sensitizers stepwise lighting up lanthanide emissions.

    PubMed

    Zhang, Yan; Jiao, Peng-Chong; Xu, Hai-Bing; Tang, Ming-Jing; Yang, Xiao-Ping; Huang, Shaoming; Deng, Jian-Guo

    2015-01-01

    Analagous to a long-ranged rocket equipped with multi-stage engines, a luminescent compound with consistent emission signals across a large range of concentrations from two stages of sensitizers can be designed. In this approach, ACQ, aggregation-caused quenching effect of sensitizers, would stimulate lanthanide emission below 10(-4) M, and then at concentrations higher than 10(-3) M, the "aggregation-induced emission" (AIE) effect of luminophores would be activated with the next set of sensitizers for lanthanide emission. Simultaneously, the concentration of the molecules could be monitored digitally by the maximal excitation wavelengths, due to the good linear relationship between the maximal excitation wavelengths and the concentrations {lg(M)}. This model, wherein molecules are assembled with two stages (both AIE and ACQ effect) of sensitizers, may provide a practicable strategy for design and construction of smart lanthanide bioprobes, which are suitable in complicated bioassay systems in which concentration is variable. PMID:25791467

  13. Texas bank eases facility emissions compliance

    SciTech Connect

    Reiman, R.L.

    1997-04-01

    Tight clean air laws-which may get much tighter-make storage facility construction and expansion difficult. New or expanded facilities, if located in an area that exceeds National Ambient Air Quality Standards (NAAQS) levels, would have to offset any emission of volatile organic compounds (FOCs) or oxides of nitrogen (NO{sub x}) that a terminal would add to the area. Offsets are often achieved with emission reduction credits (ERCs). In some areas, however, ERCs can be hard to find. This could stymie development in areas strategic to petroleum storage and distribution. To make these ERCs readily available, the Texas Natural Resource Conservation Commission (TNRCC) formed an ERC clearinghouse in 1993 for each of the Texas regions that exceed NAAQS ozone levels. Emissions reduction credits can be purchased through the Texas Natural Resource Conservation Commission`s Emissions Bank Status Report on the Internet.

  14. 40 CFR 63.8050 - How do I comply with emissions averaging for stationary process vessels at existing sources?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...ER11DE03.002 ER11DE03.003 where: S1 =saturation factor for individual condensable compounds in the emission stream Pi =partial pressure of individual condensable compounds in the emission stream calculated using Raoult's Law or other...

  15. 40 CFR 63.8050 - How do I comply with emissions averaging for stationary process vessels at existing sources?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...ER11DE03.002 ER11DE03.003 where: S1 =saturation factor for individual condensable compounds in the emission stream Pi =partial pressure of individual condensable compounds in the emission stream calculated using Raoult's Law or other...

  16. 40 CFR 63.8050 - How do I comply with emissions averaging for stationary process vessels at existing sources?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...ER11DE03.002 ER11DE03.003 where: S1 = saturation factor for individual condensable compounds in the emission stream Pi = partial pressure of individual condensable compounds in the emission stream calculated using Raoult's Law or other...

  17. 40 CFR 63.8050 - How do I comply with emissions averaging for stationary process vessels at existing sources?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...ER11DE03.002 ER11DE03.003 where: S1 =saturation factor for individual condensable compounds in the emission stream Pi =partial pressure of individual condensable compounds in the emission stream calculated using Raoult's Law or other...

  18. Compound curvature laser window development

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.

    1993-01-01

    The NASA Lewis Research Center has developed and implemented a unique process for forming flawless compound curvature laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report summarizes the main aspects of compound curvature laser window development. It is an overview of the methodology and the peculiarities associated with the formulation of these windows. Included in this discussion is new information regarding procedures for compound curvature laser window development.

  19. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1993-01-01

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains colloidal silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{sup TM}, LEXAN{sup TM}, LUCITE{sup TM}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  20. Michigan`s air emission trading program

    SciTech Connect

    Russette, T.M.; VanKolken, A.M.

    1997-12-31

    Michigan`s Emission Trading Program took effect on March 16, 1996 after two years of rule development by the Michigan Department of Environmental Quality, Air Quality Division and affected stakeholders. This program is based on the open market trading model and has been designed to (1) be consistent with existing federal and state rules and regulations, (2) integrate with existing air programs such as the permit program, and (3) address the needs of Michigan`s regulated community. Michigan`s Air Quality Division, along with other interested parties, initiated this program as part of market-based approaches to improve air quality through the reduction of criteria pollutants (except ozone) and volatile organic compounds. The Emission Trading rules offer potential benefits for Michigan companies that include increased operational flexibility, lower compliance costs, and/or money generated from the sale of the emission reduction credits. The environment also benefits from this program because the rules require that 10 percent of all registered emission reductions must be permanently retired as an air quality benefit. The emission trading program provides new opportunities for consulting firms to assist companies by identifying acceptable ways to generate and use emission reduction credits. Air pollution control companies may also see new opportunities by designing and installing control equipment in order to reduce air emissions. The role of consultants and equipment companies may expand to that of a broker selling and/or buying emission reduction credits on the Emission Trading Registry. Much has been learned since the conception of the air emission trading program. This paper will discuss how the program works in practice compared to what was envisioned in theory and the potential benefits from Michigan`s Emission Trading Program.

  1. Optical amplification and stability of spiroquaterphenyl compounds and blends

    NASA Astrophysics Data System (ADS)

    Fuhrmann-Lieker, T.; Lambrecht, J.; Hoinka, N.; Kiurski, M.; Wiske, A.; Hagelstein, G.; Yurttagül, Y.; Abdel-Awwad, M.; Wilke, H.; Messow, F.; Hillmer, H.; Salbeck, J.

    2015-02-01

    In this contribution, we present a systematic investigation on a series of spiroquaterphenyl compounds optimised for solid state lasing in the near ultraviolet (UV). Amplified spontaneous emission (ASE) thresholds in the order of 1 ?J/cm^2 are obtained in neat (undiluted) films and blends, with emission peaks at 390±1 nm for unsubstituted and meta-substituted quaterphenyls and 400±4 nm for para-ether substituted quaterphenyls. Mixing with a transparent matrix retains a low threshold, shifts the emission to lower wavelengths and allows a better access to modes having their intensity maximum deeper in the film. Chemical design and blending allow an independent tuning of optical and processing properties such as the glass transition.

  2. Compound cueing in free recall

    PubMed Central

    Lohnas, Lynn J.; Kahana, Michael J.

    2013-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cueing in free recall. Specifically, the temporal contiguity effect should be greater when the two most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cueing in both conditional response probabilities and inter-response times. To help rule out a rehearsal-based account of these compound cueing effects, we conducted an experiment with immediate, delayed and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cueing was present in all conditions, and was not significantly influenced by the presence of interitem distractors. PMID:23957364

  3. Compound Independent and Dependent Events

    NSDL National Science Digital Library

    2007-12-12

    Compare the theoretical and experimental probability of a compound independent event by drawing colored marbles from a bag. Record the results of successive draws with or without replacement of marbles to calculate the experimental probability.

  4. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, Amy A. (Augusta, GA)

    1996-01-01

    A method for making a composition for measuring the concentration of chloated aromatic compounds in aqueous fluids, and an optical probe for use with the method. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis.

  5. The Magic of Compound Interest

    NSDL National Science Digital Library

    Mr. Gordon

    2006-10-19

    The most powerful force in the universe is compound interest - Albert Einstein - Compound interest is the underlying concept that allows your money to grow on its own and that\\'s what leads to a lucrative future. It\\'s the interest you earn off of your original investment plus the interest you\\'ve already accrued. It\\'s interest on interest. And what it can do is amazing. Compound interest\\'s a cyclical monster that feeds itself and keeps growing at an exponential rate. And the best part about compound interest is that young people have the advantage. Young, first-time investors have an upper hand on older, wiser, Wall Street investors and stock market gurus because young people have ...

  6. Biologically inspired artificial compound eyes.

    PubMed

    Jeong, Ki-Hun; Kim, Jaeyoun; Lee, Luke P

    2006-04-28

    This work presents the fabrication of biologically inspired artificial compound eyes. The artificial ommatidium, like that of an insect's compound eyes, consists of a refractive polymer microlens, a light-guiding polymer cone, and a self-aligned waveguide to collect light with a small angular acceptance. The ommatidia are omnidirectionally arranged along a hemispherical polymer dome such that they provide a wide field of view similar to that of a natural compound eye. The spherical configuration of the microlenses is accomplished by reconfigurable microtemplating, that is, polymer replication using the deformed elastomer membrane with microlens patterns. The formation of polymer waveguides self-aligned with microlenses is also realized by a self-writing process in a photosensitive polymer resin. The angular acceptance is directly measured by three-dimensional optical sectioning with a confocal microscope, and the detailed optical characteristics are studied in comparison with a natural compound eye. PMID:16645090

  7. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1991-01-01

    This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

  8. Nitric Oxide-Releasing Compounds

    NSDL National Science Digital Library

    The five WebWare Molecules for December derive from the article Nitrogen-Based Diazeniumdiolates: Versatile Nitric Oxide-Releasing Compounds for Biomedical Research and Potential Clinical Applications by Joseph E. Saavedra and Larry K. Keefer.

  9. Quantifying surface emissions of methanol using observations from the Tropospheric Emission Spectrometer

    NASA Astrophysics Data System (ADS)

    Wells, K. C.; Millet, D. B.; Cady-Pereira, K. E.; Shephard, M. W.; Luo, M.; Henze, D. K.

    2012-12-01

    Methanol is the most abundant non-methane organic compound in the atmosphere, and a precursor of carbon monoxide, formaldehyde and ozone. Biogenic emissions from terrestrial plants constitute the largest fraction of the global methanol source, while biomass burning and anthropogenic emissions can make significant contributions on a regional scale. The recent availability of tropospheric methanol observations from space provides a powerful new constraint for understanding methanol emission processes on a global scale. Here we employ two years of global methanol observations from the Tropospheric Emission Spectrometer (TES) with the adjoint of the GEOS-Chem CTM to quantify the surface methanol flux, and interpret the results in terms of emission rates from different plant functional types. The satellite data imply a downward revision of the model emissions in portions of the tropics, and an upward revision in midlatitudes. The largest increases to the model emissions occur in areas that are dominated by shrubs and grasses, suggesting a refinement in methanol emission factors as a function of plant functional type. Applying the optimized emission rates in the model results in an improvement of the simulation as compared to an ensemble of airborne and ground-based observations.

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

    EPA Science Inventory

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

  11. Aza compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.Q.; McBreen, J.

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li{sup +} ion in alkali metal batteries. 3 figs.

  12. Aza compounds as anion receptors

    SciTech Connect

    Lee, Hung Sui (East Setauket, NY); Yang, Xiao-Qing (Port Jefferson Station, NY); McBreen, James (Bellport, NY)

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li.sup.+ ion in alkali metal batteries.

  13. Miniature curved artificial compound eyes

    PubMed Central

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L’Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A.; Franceschini, Nicolas

    2013-01-01

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

  14. [Study on compound levonorgestrel microspheres].

    PubMed

    Guo, R; Lu, B

    1993-12-01

    Levonorgestrel (LNG) and estradiol (E2) were mixed in the ratio of 5:2 by weight. Compound LNG gelatin-microspheres were prepared by phase-separation method, natural biodegradable gelatin being used as the core material. The experimental conditions were optimized, the mean diameter of the microspheres obtained being 10-40 microns, and the rate of encapsulation 65-75%. Storage observations and acceleration tests of the compound LNG gelatin-microsphere injection prepared showed that the microspheres have good stability. The thermal degradation activation energy of the injection was determined to be 134.4 kJ/mol, based on differential scanning colorimetry (DSC). T1/2 values for dissolution in vitro of LNG and E2 from the compound LNG gelatin-microsphere injection and from the unencapsulated injection showed significant difference (P < 0.01), indicating that the microspheres have good sustained release action. Effects of the pure LNG microsphere injection and compound LNG microsphere injection on the mouse ovary were compared histologically. The results showed that the compound LNG microsphere injection reduced some of the side effects such as ovary congestion. This points out that the compound dosage form can clinically alleviate the irregular bleeding caused by the administration of LNG alone. PMID:8150435

  15. Miniature curved artificial compound eyes.

    PubMed

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-01

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

  16. Gas Turbine Emissions 

    E-print Network

    Frederick, J. D.

    1990-01-01

    GAS TURBINE EMISSIONS JESSE D. FREDERICK Sr. Environmental Engineer Destec Energy Houston, Texas ABSTRACT Historically, preliminary design information regarding gas turbine emissions has been unreliable, particularly for facilities...

  17. Microcomputer software reviews - CHEMDAT6: Lotus spreadsheet for estimating air emissions

    SciTech Connect

    Davis, M.

    1989-11-01

    Regulatory agencies are asking probing questions about the emissions of Valatile Organic Compounds (VOC's) from industrial sources. The Environmental Protection Agency (EPA) has developed a Lotus spreadsheet, CHEMDAT6, to assist in estimating the air emissions from sources such as surface impoundments, open tanks, land treatment units, wastepiles, and waste handling facilities. The emission rates calculated by CHEMDAT6 may be used as input for further analyses, such as dispersion modeling, to determine the potential health impact of the calculated emissions.

  18. A microscale device for measuring emissions from materials for indoor use

    Microsoft Academic Search

    T. Schripp; B. Nachtwey; J. Toelke; T. Salthammer; E. Uhde; M. Wensing; M. Bahadir

    2007-01-01

    Emission test chambers or cells are used to determine organic vapour emissions from construction products under controlled\\u000a conditions. Polymeric car trim component emissions are typically evaluated using direct thermal desorption\\/extraction. The\\u000a Microchamber\\/Thermal Extractor (?-CTE, Markes International) was developed to provide both a complementary tool for rapid\\u000a screening of volatile organic compound (VOC) emissions—suitable for industrial quality control—and a means for

  19. Human Health Damages due to Indoor Sources of Organic Compounds and Radioactivity in Life Cycle Impact Assessment of Dwellings

    Microsoft Academic Search

    Arjen Meijer; Mark AJ Huijbregts; Lucas Reijnders

    Preamble. In this series of two papers, a methodology to calculate damages to human health caused by indoor emissions from building materials is presented and applied. Part 1 presents the theoretical foundation of the indoor emission methodology developed, as well as characterisation factors calculated for 36 organic compounds, radon and gamma radiation. Part 2 calculates damage scores of building materials

  20. Biogenic VOC Emissions from Tropical Landscapes

    NASA Astrophysics Data System (ADS)

    Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

    2003-04-01

    Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.