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Sample records for airborne black carbon

  1. Effects of airborne black carbon pollution on maize

    NASA Astrophysics Data System (ADS)

    Illes, Bernadett; Anda, Angela; Soos, Gabor

    2013-04-01

    The black carbon (BC) changes the radiation balance of the Earth and contributes to global warming. The airborne BC deposited on the surface of plant, changing the radiation balance, water balance and the total dry matter (TDM) content of plant. The objective of our study was to investigate the impact of soot originated from motor vehicle exhaust on maize. The field experiment was carried out in Keszthely Agrometeorological Research Station (Hungary) in three consecutive years (2010, 2011, 2012) of growing season. The test plant was the maize hybrid Sperlona (FAO 340) with short growing season. The BC was chemically "pure", which means that it is free any contaminants (e.g. heavy metals). The BC was coming from the Hankook Tyre Company (Dunaújváros, Hungary), where used that for improve the wear resistance of tires. We used a motorised sprayer of SP 415 type to spray the BC onto the leaf surface. The leaf area index (LAI) was measured each week on the same 12 sample maize in each treatment using an LI 3000A automatic planimeter (LI-COR, Lincoln, NE). Albedo was measured by pyranometers of the CMA-11 type (Kipp & Zonen, Vaisala), what we placed the middle of the plot of 0.3 ha. The effects of BC were studied under two different water supplies: evapotranspirometers of Thornthwaite type were used for "ad libitum" treatment and rainfed treatment in field plots. In 2010 and 2012, a big difference was not observed in the case of LAI in the effects of BC. However, in 2011 there was a significant difference. The LAI of the BC polluted maize was higher (10-15%, P<0.05), than the LAI of the control maize in the rainfed plot and in the ET chambers, respectively. The albedo of the BC contaminated maize decreased (15-30%, P<0.05) in all three years. We also detected that the green plant surface of maize increased on BC contaminated treatment. These results may suggest that the plant is able to absorb the additional carbon source through the leaves. The albedo decreased

  2. Domestic airborne black carbon and exhaled nitric oxide in children in NYC

    PubMed Central

    Cornell, Alexandra G.; Chillrud, Steven N.; Mellins, Robert B.; Acosta, Luis M.; Miller, Rachel L.; Quinn, James W.; Yan, Beizhan; Divjan, Adnan; Olmedo, Omar E.; Lopez-Pintado, Sara; Kinney, Patrick L.; Perera, Frederica P.; Jacobson, Judith S.; Goldstein, Inge F.; Rundle, Andrew G.; Perzanowski, Matthew S.

    2012-01-01

    Differential exposure to combustion by-products and allergens may partially explain the marked disparity in asthma prevalence (3%–18%) among New York City neighborhoods. Subclinical changes in airway inflammation can be measured by fractional exhaled nitric oxide (FeNO). FeNO could be used to test independent effects of these environmental exposures on airway inflammation. Seven and eight year-old children from neighborhoods with lower (range 3–9%, n=119) and higher (range 11–18%, n=121) asthma prevalence participated in an asthma case-control study. During home visits, FeNO was measured, and samples of bed dust (allergens) and air (black carbon) were collected. Neighborhood built-environment characteristics were assessed for the 500m surrounding participants’ homes. Airborne black carbon concentrations in homes correlated with neighborhood asthma prevalence (P<0.001) and neighborhood densities of truck routes (P<0.001) and buildings burning residual oil (P<0.001). FeNO concentrations were higher among asthmatics with compared to asthmatics without frequent wheeze (≥4 times/year) (P=0.002). FeNO concentrations correlated with domestic black carbon among children without seroatopy (P=0.012) and with dust mite allergen among children with seroatopy (P=0.020). The association between airborne black carbon in homes and both neighborhood asthma prevalence and FeNO suggest that further public health interventions on truck emissions standards and residual oil use are warranted. PMID:22377682

  3. Long-term Airborne Black Carbon Measurements on a Lufthansa Passenger Aircraft

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Su, H.; Ditas, J.; Scharffe, D.; Wang, S.; Zhang, Y.; McMeeking, G. R.; Brenninkmeijer, C. A. M.; Poeschl, U.

    2015-12-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO2 the strongest component of current global warming. Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free troposphere, and in the UTLS (upper troposphere and lower stratosphere). In August 2014, a single particle soot photometer (SP2) was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 and carries out systematic observations of trace gas and aerosol sampling and on-line analyses, as well as DOAS remote sensing system at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The integration of a SP2 offers the possibility for the first long-term measurement of global distribution of black carbon. Up to date the SP2 measurements have been analyzed for 392 flights hours over four continents (Fig. 1). The first measurements show promising results of black carbon including periods when background concentrations in the UTLS were encountered. Beside a general distribution of number and mass of black carbon particles, peak events were detected with up to 20 times higher concentrations compared to the background. Moreover, high concentration plumes have been observed continuously over a range of 10,000 km. Interestingly, our results show also a generally lower amount of black carbon mass in the tropics compared to the mid latitude northern hemisphere.

  4. Long-term airborne black carbon measurements on a Lufthansa passenger aircraft

    NASA Astrophysics Data System (ADS)

    Ditas, Jeannine; Su, Hang; Scharffe, Dieter; Wang, Siwen; Zhang, Yuxuan; Brenninkmeijer, Carl; Pöschl, Ulrich; Cheng, Yafang

    2016-04-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO² the strongest component of current global warming (Bond, 2013). Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free and upper troposphere, and in the UTLS (upper troposphere and lower stratosphere). Many models underestimate the global atmospheric absorption attributable to black carbon by a factor of almost 3 (Bond, 2013). In August 2014, a single particle soot photometer was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 (with an interruption for 2002-2005) and carries out systematic observations at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The container has equipment for trace gas analyses and sampling and aerosol analyses and sampling and is connected to an inlet system that is part of the aircraft which contains a camera and DOAS remote sensing system. The integration of a single particle soot photometer (SP2) offers the possibility for the first long-term measurement of global distribution of black carbon and so far flights up to November 2015 have been conducted with more than 400 flight hours. So far the SP2 measurements have been analysed for flights over four continents from Munich to San Francisco, Sao Paulo, Tokyo, Beijing, Cape Town, Los Angeles and Hong Kong). The first measurements show promising results of black carbon measurements. Background concentrations in the UTLS

  5. Airborne measurements of Black Carbon using miniature high-performance Aethalometers during global circumnavigation campaign GLWF 2012

    NASA Astrophysics Data System (ADS)

    Močnik, Griša; Drinovec, Luka; Vidmar, Primož; Lenarčič, Matevž

    2013-04-01

    While ground-level measurements of atmospheric aerosols are routinely performed around the world, there exists very little data on their vertical and geographical distribution in the global atmosphere. This data is a crucial requirement for our understanding of the dispersion of pollutant species of anthropogenic origin, and their possible effects on radiative forcing, cloud condensation, and other phenomena which can contribute to adverse outcomes. Black Carbon (BC) is a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. It has no non-combustion sources and is not transformed by atmospheric processes. Its presence at altitude is unequivocal. Recent technical advances have led to the development of miniaturized instruments which can be operated on ultra-light aircraft, balloons or UAV's. From January to April 2012, a 'Pipistrel Virus' single-seat ultra-light aircraft flew around the world on a photographic and environmental-awareness mission. The flight track covered all seven continents; crossed all major oceans; and operated at altitudes around 3000 m ASL and up to 8900 m ASL. The aircraft carried a specially-developed high-sensitivity miniaturized dual-wavelength Aethalometer, which recorded BC concentrations with very high temporal resolution and sensitivity (see Reference below). We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas. Back-trajectories are used to show transport of polluted air masses. Measuring the dependence of the aerosol absorption on the wavelength, we show that aerosols produced during biomass combustion can be transported to high altitude in high concentrations. 1. __, Carbon Sampling Takes Flight, Science 2012, 335, 1286. 2. G. Močnik, L. Drinovec, M. Lenarčič, Airborne measurements of Black Carbon during the GLW Flight using miniature high-performance Aethalometers, accessed 8 January 2013

  6. Domestic airborne black carbon levels and 8-isoprostane in exhaled breath condensate among children in New York City☆

    PubMed Central

    Rosa, Maria Jose; Yan, Beizhan; Chillrud, Steven N.; Acosta, Luis M.; Divjan, Adnan; Jacobson, Judith S.; Miller, Rachel L.; Goldstein, Inge F.; Perzanowski, Matthew S.

    2015-01-01

    Background Exposure to airborne black carbon (BC) has been associated with asthma development, respiratory symptoms and decrements in lung function. However, the mechanism through which BC may lead to respiratory symptoms has not been completely elucidated. Oxidative stress has been suggested as a potential mechanism through which BC might lead to adverse health outcomes. Exhaled breath condensate (EBC) allows for the non-invasive collection of airway lining fluid containing biomarkers of oxidative stress like 8-isoprostane, a stable by-product of lipid peroxidation. Therefore, we sought to characterize the association between domestic airborne BC concentrations and 8-isoprostane in EBC. Materials and methods Seven- and eight-year-old children participated in an asthma case–control study in New York City. During home visits, air samples and EBC were collected. Seven day averages of domestic levels of particulate matter <2.5 µm (PM2.5), BC and environmental tobacco smoke (ETS) were measured. Urea and 8-isoprostane were measured by liquid chromatography tandem mass spectrometry (LC/MS/MS) in EBC. Results In univariate models, PM2.5 and BC, but not ETS, were significantly associated with increases in 8-isoprostane in the EBC (β = 0.006 and β = 0.106 respectively, p < 0.05 for both). These associations remained statistically significant for both PM2.5 and BC after adjustment for covariates. In a co-pollutant model including PM2.5, BC and ETS, only BC remained a statistically significant predictor of 8-isoprostane (p < 0.05). Conclusions Our findings suggest the BC fraction of PM might contain exposure relevant to increased oxidative stress in the airways. PMID:25262082

  7. Atmospheric profiles of Black Carbon at remote locations using light-weight airborne Aethalometers

    NASA Astrophysics Data System (ADS)

    Hansen, A. D.; Močnik, G.; Drinovec, L.; Lenarcic, M.

    2012-12-01

    While measurements of atmospheric aerosols are routinely performed at ground-level around the world, there is far less knowledge of their concentrations at altitude: yet this data is a crucial requirement for our understanding of the dispersion of pollutants of anthropogenic origin, with their associated effects on radiative forcing, cloud condensation, and other adverse phenomena. Black Carbon (BC) is a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. It has no non-combustion sources and is not transformed by atmospheric processes. Recent technical advances have developed light-weight miniaturized instruments which can be operated on light aircraft or carried aboard commercial passenger flights. From January to April 2012, a single-seat ultra-light aircraft flew around the world on a scientific, photographic and environmental-awareness mission. The flight track crossed all seven continents and all major oceans, with altitudes up to 8.9 km ASL. The aircraft carried a custom-developed high-sensitivity dual-wavelength light-weight Aethalometer, operating at 370 and 880 nm with special provision to compensate for the effects of changing pressure, temperature and humidity. The instrument recorded BC concentrations with high temporal resolution and sensitivity better than 5 ng/m3. We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas, analyzing the spectral dependence of absorption to infer the contributions to BC from fossil fuel vs. biomass combustion, and aggregating the data into vertical profiles. The regional and long range transport of BC may be investigated using back-trajectories. We have also operated miniature instruments in the passenger cabins of long-distance commercial aircraft. Since there are no combustion sources within the cabin, any BC in the ventilation air must necessarily have originated from the outside

  8. Airborne black carbon concentrations over an urban region in western India-temporal variability, effects of meteorology, and source regions.

    PubMed

    Bapna, Mukund; Sunder Raman, Ramya; Ramachandran, S; Rajesh, T A

    2013-03-01

    This study characterizes over 5 years of high time resolution (5 min), airborne black carbon (BC) concentrations (July 2003 to December 2008) measured over Ahmedabad, an urban region in western India. The data were used to obtain different time averages of BC concentrations, and these averages were then used to assess the diurnal, seasonal, and annual variability of BC over the study region. Assessment of diurnal variations revealed a strong association between BC concentrations and vehicular traffic. Peaks in BC concentration were co-incident with the morning (0730 to 0830, LST) and late evening (1930 to 2030, LST) rush hour traffic. Additionally, diurnal variability in BC concentrations during major festivals (Diwali and Dushera during the months of October/November) revealed an increase in BC concentrations due to fireworks displays. Maximum half hourly BC concentrations during the festival days were as high as 79.8 μg m(-3). However, the high concentrations rapidly decayed suggesting that local meteorology during the festive season was favorable for aerosol dispersion. A multiple linear regression (MLR) model with BC as the dependent variable and meteorological parameters as independent variables was fitted. The variability in temperature, humidity, wind speed, and wind direction accounted for about 49% of the variability in measured BC concentrations. Conditional probability function (CPF) analysis was used to identify the geographical location of local source regions contributing to the effective BC measured (at 880 nm) at the receptor site. The east north-east (ENE) direction to the receptor was identified as a major source region. National highway (NH8) and two coal-fired thermal power stations (at Gandhinagar and Sabarmati) were located in the identified direction, suggesting that local traffic and power plant emissions were likely contributors to the measured BC. PMID:22777610

  9. What do we learn from EC (black carbon), OC and their Isotope Measurements in Fine Airborne PM over Canada?

    NASA Astrophysics Data System (ADS)

    Huang, L.; Zhang, W.; Sharma, S.; Brook, J.; Chan, T.; Leaitch, R.

    2009-04-01

    Elemental carbon and organic carbon (EC & OC) components in fine airborne carbonaceous particulate matter (PM) are major air pollutants existing in urban, rural and remote environments as well as key players in climate change (via radiative forcing). It is known that both EC (also called as black carbon or soot) and OC are released from various emission sources (e.g., fossil fuel combustion, biomass burning) and OC is also produced in the atmosphere through photochemical oxidations from gas phase organics. Tracking their spatial (e.g., from urban to rural to background air or latitudinal) and temporal (e.g. seasonal and inter-annual) distributions will provide valuable information to constraining emission sources and atmospheric transport/transformation mechanisms as well as to assessing effectiveness of mitigation for these pollutants. Sources/processes detecting and attributing are key aspects in both air quality and climate change research. Isotope measurements, as independent tools, can provide valuable insight to constrain those aspects. Duo to its inert nature, it is expected that the ^13C of EC won't be changed after emitting to the atmosphere, reflecting the signature of source, whereas the ^13Cof OC will have a various degree of changes through photochemical processes, depending on the history of the air mass. Therefore, an isotopic profile of ^13C in carbon components released at different temperature ranges can provide useful insight to the emission sources and formation processes in ambient PM. Quartz filter samples were collected at the five sites over Canada, from Toronto (a typical urban site), Egbert (a rural site, ~ 80 km northwest of Toronto), to Fraserdale, and Berm-TT (both are continental boreal forest sites), to Alert (an Arctic baseline site). EC and OC concentrations for those samples collected during the period (2006 - 2007) were determined using a thermal method (Totoal_900_EnCan) developed in Toronto lab at Environment Canada, which is

  10. Airborne measurements of black carbon aerosol over the Southeastern U.S. during the Southeast Atmosphere Study (SAS) experiment

    NASA Astrophysics Data System (ADS)

    Markovic, M. Z.; Perring, A. E.; Schwarz, J. P.; Fahey, D. W.; Gao, R.; Watts, L.; Holloway, J.; Graus, M.; Warneke, C.; De Gouw, J. A.; Veres, P. R.; Roberts, J. M.; Middlebrook, A. M.; Welti, A.; Liao, J.

    2013-12-01

    The Southeast Atmosphere Study (SAS) field campaign was a large-scale, collaborative project, which took place in the Southeastern U.S. in June and July of 2013. The goal of the campaign was to investigate the impacts of biogenic and anthropogenic gases and aerosols on the formation of haze and anomalous climate cooling in the region. During SAS, a NOAA Single Particle Soot Photometer (SP2) instrument was utilized onboard NOAA WP-3D research aircraft for measurements of black carbon (BC) aerosol mass and microphysical properties. BC aerosol is emitted into the atmosphere from biomass burning (BB) and incomplete combustion of fossil and biofuel. Hence, BC sources are strongly linked to anthropogenic activity. BC aerosol is currently the second largest anthropogenic climate forcing agent after CO2(g), and its climate impacts, which depend on vertical burden and internal mixing, are not fully understood. In the Southeast, BC aerosol is expected to provide surface area for the condensation of semi-volatile products of VOC oxidation and subsequent formation of secondary organic aerosol (SOA). Hence, BC is expected to impact the haze formation and regional climate. In this work we present an overview of BC measurements during Southeast Nexus (SENEX) study, the NOAA contribution to SAS. Geographical variations in mass mixing ratios, mass size distributions, and mixing state of BC over the Southeast U.S. are discussed. Relationships of BC with carbon monoxide (CO), acetonitrile (ACN) and other trace gases are used to investigate the impacts of urban, BB, natural gas development, and power plant emissions on the distribution and properties of BC aerosol in the region. Among studied urban centers, St. Louis and Atlanta were determined to be the largest source regions of BC. A clear weekend effect in BC mass mixing ratios and microphysical properties was observed in the metropolitan Atlanta region. Compared to BB and urban centers, power plants and natural gas developments

  11. 'Glory and the Curse of the Black Carbon'

    NASA Video Gallery

    NASA's Glory spacecraft will improve our understanding of how the sun and airborne particles called aerosols (black carbons among them), affect Earth's climate. Set to launch February 2011, the mis...

  12. SOURCE ASSESSMENT: CARBON BLACK MANUFACTURE

    EPA Science Inventory

    The report summarizes the assessment of air emissions from the manufacture of carbon black, currently manufactured in the U.S. by two major processes: thermal and oil furnace. Sources of atmospheric emissions within oil furnace plants (about 90% of the 30 U.S. carbon black plants...

  13. Pyrolytic carbon coated black silicon.

    PubMed

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm. PMID:27174890

  14. Pyrolytic carbon coated black silicon

    NASA Astrophysics Data System (ADS)

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N.; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-05-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm.

  15. Pyrolytic carbon coated black silicon

    PubMed Central

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N.; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm. PMID:27174890

  16. Black Carbon as an Additional Indicator of the Adverse Health Effects of Airborne Particles Compared with PM10 and PM2.5

    PubMed Central

    Hoek, Gerard; Simic-Lawson, Milena; Fischer, Paul; van Bree, Leendert; ten Brink, Harry; Keuken, Menno; Atkinson, Richard W.; Anderson, H. Ross; Brunekreef, Bert; Cassee, Flemming R.

    2011-01-01

    Background: Current air quality standards for particulate matter (PM) use the PM mass concentration [PM with aerodynamic diameters ≤ 10 μm (PM10) or ≤ 2.5 μm (PM2.5)] as a metric. It has been suggested that particles from combustion sources are more relevant to human health than are particles from other sources, but the impact of policies directed at reducing PM from combustion processes is usually relatively small when effects are estimated for a reduction in the total mass concentration. Objectives: We evaluated the value of black carbon particles (BCP) as an additional indicator in air quality management. Methods: We performed a systematic review and meta-analysis of health effects of BCP compared with PM mass based on data from time-series studies and cohort studies that measured both exposures. We compared the potential health benefits of a hypothetical traffic abatement measure, using near-roadway concentration increments of BCP and PM2.5 based on data from prior studies. Results: Estimated health effects of a 1-μg/m3 increase in exposure were greater for BCP than for PM10 or PM2.5, but estimated effects of an interquartile range increase were similar. Two-pollutant models in time-series studies suggested that the effect of BCP was more robust than the effect of PM mass. The estimated increase in life expectancy associated with a hypothetical traffic abatement measure was four to nine times higher when expressed in BCP compared with an equivalent change in PM2.5 mass. Conclusion: BCP is a valuable additional air quality indicator to evaluate the health risks of air quality dominated by primary combustion particles. PMID:21810552

  17. ARM Airborne Continuous carbon dioxide measurements

    DOE Data Explorer

    Biraud, Sebastien

    2013-03-26

    The heart of the AOS CO2 Airborne Rack Mounted Analyzer System is the AOS Manifold. The AOS Manifold is a nickel coated aluminum analyzer and gas processor designed around two identical nickel-plated gas cells, one for reference gas and one for sample gas. The sample and reference cells are uniquely designed to provide optimal flushing efficiency. These cells are situated between a black-body radiation source and a photo-diode detection system. The AOS manifold also houses flow meters, pressure sensors and control valves. The exhaust from the analyzer flows into a buffer volume which allows for precise pressure control of the analyzer. The final piece of the analyzer is the demodulator board which is used to convert the DC signal generated by the analyzer into an AC response. The resulting output from the demodulator board is an averaged count of CO2 over a specified hertz cycle reported in volts and a corresponding temperature reading. The system computer is responsible for the input of commands and therefore works to control the unit functions such as flow rate, pressure, and valve control.The remainder of the system consists of compressors, reference gases, air drier, electrical cables, and the necessary connecting plumbing to provide a dry sample air stream and reference air streams to the AOS manifold.

  18. Longitudinal variability of black carbon vertical profiles

    NASA Astrophysics Data System (ADS)

    Schwarz, J. P.; Weinzierl, B.; Samset, B. H.; Perring, A. E.; Dollner, M.; Heimerl, K.; Markovic, M. Z.; Ziemba, L. D.

    2015-12-01

    Black carbon (BC) aerosol contributes substantially to both climate forcing and climate forcing uncertainty. An important source of this uncertainty derives from the difficulty in predicting BC's global abundance and vertical distribution. Here we present a multi-year record of black carbon (BC) vertical concentration profiles from both sides of the Atlantic, obtained from airborne Single Particle Soot Photometers (SP2s) flown on the NASA DC-8, and the DLR Falcon research aircraft from the CONCERT, ACCESS, DC3, SEAC4RS, and SALTRACE campaigns. The measurements constrain the relative rates of BC transport/removal from, and zonal mixing in, the upper troposphere, as well as the range of BC loadings in these regions. They also constrain the time-rates of change of BC loads in altitudes at which it is a highly efficient (although sparse) climate forcer, and a relatively long-lived aerosol tracer. We find that concentration of BC in the upper troposphere can vary by a factor 10. Over the Northern mid-latitudes concentrations are however consistent to a fraction of this range over wide longitudinal ranges, over month-long timescales. The data show that BC becomes zonally mixed here starting at 500 hPa and extending to near the tropopause. These results imply broader value than previously associated with measured vertical profiles in constraining global scale BC loadings aloft.

  19. Airborne Oceanographic Lidar (AOL) (Global Carbon Cycle)

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This bimonthly contractor progress report covers the operation, maintenance and data management of the Airborne Oceanographic Lidar and the Airborne Topographic Mapper. Monthly activities included: mission planning, sensor operation and calibration, data processing, data analysis, network development and maintenance and instrument maintenance engineering and fabrication.

  20. Low-Wind and Other Microclimatic Factors in Near-road Black Carbon Variability: A Case Study and Assessment Implications

    EPA Science Inventory

    Airborne black carbon from urban traffic is a climate forcing agent and has been associated with health risk to near-road populations. In this paper, we describe a case study of black carbon concentration and compositional variability at and near a traffic-laden multi-lane highw...

  1. Black carbon contribution to global warming

    SciTech Connect

    Chylek, P.; Johnson, B.; Kou, L.; Wong, J.

    1996-12-31

    Before the onset of industrial revolution the only important source of black carbon in the atmosphere was biomass burning. Today, black carbon production is divided between the biomass and fossil fuel burning. Black carbon is a major agent responsible for absorption of solar radiation by atmospheric aerosols. Thus black carbon makes other aerosols less efficient in their role of reflecting solar radiation and cooling the earth-atmosphere system. Black carbon also contributes to the absorption of solar radiation by clouds and snow cover. The authors present the results of black carbon concentrations measurements in the atmosphere, in cloud water, in rain and snow melt water collected during the 1992--1996 time period over the southern Nova Scotia. Their results are put into the global and historical perspective by comparing them with the compilation of past measurements at diverse locations and with their measurements of black carbon concentrations in the Greenland and Antarctic ice cores. Black carbon contribution to the global warming is estimated, and compared to the carbon dioxide warming, using the radiative forcing caused by the black carbon at the top of the atmosphere.

  2. Coal as a Substitute for Carbon Black

    NASA Technical Reports Server (NTRS)

    Kushida, R. O.

    1982-01-01

    New proposal shows sprayed coal powder formed by extrusion of coal heated to plastic state may be inexpensive substitute for carbon black. Carbon black is used extensively in rubber industry as reinforcing agent in such articles as tires and hoses. It is made from natural gas and petroleum, both of which are in short supply.

  3. Evolution of black carbon properties in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black carbon deposited in soil from natural or deliberate wildfires and engineered black carbon products (biochar) intentionally added to soil are known to have significant effects on soil biogeochemical processes and in many cases to influence the yield and quality of crops and to enhance the abili...

  4. Airborne Measurement of Ecosystem Carbon Dynamics over Heterogeneous Landscapes

    NASA Astrophysics Data System (ADS)

    Wade, T. J.; Hill, T. C.; Clement, R.; Moncrieff, J.; Disney, M.; Nichol, C. J.; Williams, M. D.

    2009-12-01

    Terrestrial carbon sinks are currently believed to account for the removal and storage of approximately 25% of anthropogenic carbon emissions from the atmosphere. The processes involved are numerous and complex and many feedbacks are at play. The ability to study the dynamics of different ecosystems at scales meaningful to climatic forcing is essential for understanding the key processes involved and identifying crucial sensitivities and thresholds. Airborne platforms with the requisite instrumentation offer the opportunity to directly measure biological processes and atmospheric structures at scales that are not achievable by ground measurements alone. The current generation of small research aircraft such as the University of Edinburgh’s Diamond HK36TTC ECO Dimona present excellent platforms for measurement of both the atmosphere and terrestrial surface. In this study we present results from airborne CO2/H2O flux measuring campaigns in contrasting climatic systems to quantify spatial patterns in ecosystem photosynthesis. Several airborne campaigns were undertaken in Arctic Finland, as part of the Arctic Biosphere Atmosphere Coupling at Multiple Scales (ABACUS) project (2008), and mainland UK as part of the UK Population Biology Network (UKPopNet) 2009 project, to explore the variability in surface CO2 flux across spatial scales larger than captured using conventional ground based eddy covariance. We discuss the application of our aircraft platform as a tool to address the challenge of understanding carbon dynamics within landscapes of heterogeneous vegetation class, terrain and hydrology using complementary datasets acquired from airborne eddy covariance and remote sensing.

  5. Detecting Airborne Mercury by Use of Polymer/Carbon Films

    NASA Technical Reports Server (NTRS)

    Shevade, Abhijit; Ryan, Margaret; Homer, Margie; Kisor, Adam; Jewell, April; Yen, Shiao-Pin; Manatt, Kenneth; Blanco, Mario; Goddard, William

    2009-01-01

    Films made of certain polymer/carbon composites have been found to be potentially useful as sensing films for detecting airborne elemental mercury at concentrations on the order of tens of parts per billion or more. That is to say, when the polymer/carbon composite films are exposed to air containing mercury vapor, their electrical resistances decrease by measurable amounts. Because airborne mercury is a health hazard, it is desirable to detect it with great sensitivity, especially in enclosed environments in which there is a risk of a mercury leak from lamps or other equipment. The present effort to develop polymerbased mercury-vapor sensors complements the work reported in NASA Tech Briefs Detecting Airborne Mercury by Use of Palladium Chloride (NPO- 44955), Vol. 33, No. 7 (July 2009), page 48 and De tecting Airborne Mer cury by Use of Gold Nanowires (NPO-44787), Vol. 33, No. 7 (July 2009), page 49. Like those previously reported efforts, the present effort is motivated partly by a need to enable operation and/or regeneration of sensors under relatively mild conditions more specifically, at temperatures closer to room temperature than to the elevated temperatures (greater than 100 C ) needed for regeneration of sensors based on noble-metal films. The present polymer/carbon films are made from two polymers, denoted EYN1 and EYN2 (see Figure 1), both of which are derivatives of poly-4-vinyl pyridine with amine functional groups. Composites of these polymers with 10 to 15 weight percent of carbon were prepared and solution-deposited onto the JPL ElectronicNose sensor substrates for testing. Preliminary test results showed that the resulting sensor films gave measurable indications of airborne mercury at concentrations on the order of tens of parts per billion (ppb) or more. The operating temperature range for the sensing films was 28 to 40 C and that the sensor films regenerated spontaneously, without heating above operating temperature (see Figure 2).

  6. Biophysical influence of airborne carbon nanomaterials on natural pulmonary surfactant.

    PubMed

    Valle, Russell P; Wu, Tony; Zuo, Yi Y

    2015-05-26

    Inhalation of nanoparticles (NP), including lightweight airborne carbonaceous nanomaterials (CNM), poses a direct and systemic health threat to those who handle them. Inhaled NP penetrate deep pulmonary structures in which they first interact with the pulmonary surfactant (PS) lining at the alveolar air-water interface. In spite of many research efforts, there is a gap of knowledge between in vitro biophysical study and in vivo inhalation toxicology since all existing biophysical models handle NP-PS interactions in the liquid phase. This technical limitation, inherent in current in vitro methodologies, makes it impossible to simulate how airborne NP deposit at the PS film and interact with it. Existing in vitro NP-PS studies using liquid-suspended particles have been shown to artificially inflate the no-observed adverse effect level of NP exposure when compared to in vivo inhalation studies and international occupational exposure limits (OELs). Here, we developed an in vitro methodology called the constrained drop surfactometer (CDS) to quantitatively study PS inhibition by airborne CNM. We show that airborne multiwalled carbon nanotubes and graphene nanoplatelets induce a concentration-dependent PS inhibition under physiologically relevant conditions. The CNM aerosol concentrations controlled in the CDS are comparable to those defined in international OELs. Development of the CDS has the potential to advance our understanding of how submicron airborne nanomaterials affect the PS lining of the lung. PMID:25929264

  7. EVALUATION OF CARBON BLACK SLURRIES AS CLEAN BURNING FUELS

    EPA Science Inventory

    Experiments were performed to examine the pumpability, atomization and combustion characteristics of slurries made of mixtures of carbon black with No. 2 fuel oil and methanol. Carbon black-No. 2 fuel oil and carbon black-methanol slurries, with carbon black contents of up to 50 ...

  8. Intercontinental transport of black carbon to the Arctic free troposphere

    NASA Astrophysics Data System (ADS)

    Liu, Dantong; Quennehen, Boris; Allan, James; Darbyshire, Eoghan; Williams, Paul; Taylor, Jonathan; Flynn, Michael; Bower, Keith; Coe, Hugh

    2015-04-01

    Black carbon has a large radiative forcing potential in the Arctic, through altering the atmosphere's radiative balance and also initiating ice melt after deposition. Here we present an analysis of aerosol data collected aboard the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft during five flights in the free troposphere in the region of Svalbard in March 2013 as part of the Natural Environment Research Council (NERC) Aerosol-Cloud Coupling and Climate Interaction in the Arctic (ACCACIA) project. A number of discrete layers of pollution typical of continental emissions were detected, evidenced by black carbon (measured using a single particle soot photometer), carbon monoxide, organic matter and sulphate (measured using an aerosol mass spectrometer). These were detected at all altitudes within the free troposphere (up to 8 km) and potential source regions were investigated on a plume-by-plume basis using FLEXPART and HYSPLIT. Continental areas were identified as separate potential sources for the different plumes, with transit times of up to 12 days. East Asia showed the strongest influence, being responsible for high concentration plumes at all layers and Europe was found to be responsible for plumes in the lower to mid troposphere. North America had a somewhat weaker influence and no significant influence from Northern Russia was found. Emissions inventory data was used in conjunction with the FLEXPART potential source footprints to try to estimate the relative significance of different sources and it was found that direct emissions from human activities (e.g. transport, industry) were more prevalent than open biomass burning. Significant loadings were detected (of the order of 100 ng sm-3 black carbon relative to CO concentrations of around 50 ppbv) even when instrumental data and model outputs suggest that significant precipitation occurred during uplift, indicating that inefficient scavenging is taking place.

  9. Modified carbon black materials for lithium-ion batteries

    DOEpatents

    Kostecki, Robert; Richardson, Thomas; Boesenberg, Ulrike; Pollak, Elad; Lux, Simon

    2016-06-14

    A lithium (Li) ion battery comprising a cathode, a separator, an organic electrolyte, an anode, and a carbon black conductive additive, wherein the carbon black has been heated treated in a CO.sub.2 gas environment at a temperature range of between 875-925 degrees Celsius for a time range of between 50 to 70 minutes to oxidize the carbon black and reduce an electrochemical reactivity of the carbon black towards the organic electrolyte.

  10. Black Carbon, The Pyrogenic Clay Mineral?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most soils contain significant amounts of black carbon, much of which is present as discrete particles admixed with the coarse clay fraction (0.2–2.0 µm e.s.d.) and can be physically separated from the more abundant diffuse biogenic humic materials. Recent evidence has shown that naturally occurring...

  11. Brominated carbon black: An EDXD study

    SciTech Connect

    Carbone, Marilena; Gontrani, Lorenzo

    2014-06-19

    An energy dispersive X-Ray study of pure and brominated carbon black was carried out. The analysis of the diffraction patterns reveals that the low bromine load (ca.1% mol) is trapped into the structure, without significantly modifying it. This allows the application of the difference methods, widely tested for electrolyte solutions, inorganic matrices containing metals and isomorphic substitutions.

  12. Carbon black and carbon black-conducting polymer composites for environmental applications

    SciTech Connect

    Rajeshwar, K.; Wampler, W.A.; Goeringer, S.; Gerspacher, M.

    1996-12-31

    A large fraction of the carbon black commercially produced in the U. S. and other parts of the world goes into the automobile tire industry and other rubber applications. However, specialty applications of this material are expected to grow in the future. The present study explores the applicability of composites of carbon black and an electronically conductive polymer, polypyrrole, in environmental pollution abatement scenarios. Chromium was used as a model environmental pollutant for demonstration of our approach.

  13. Cross-sectional study of pulmonary function in carbon black workers in the United States

    SciTech Connect

    Robertson, J.M.; Diaz, J.F.; Fyfe, I.M.; Ingalls, T.H.

    1988-04-01

    Since a proportion of airborne carbon black particles is of respirable size, the possibility that it may affect pulmonary function was investigated in 913 employees of 6 carbon black producers in the United States. Exposure was estimated by combining the mean total dust exposures of each job category with the length of time workers had spent in each job, giving a measurement expressed in mg/m3.months. Pulmonary function was measured by spirometry. The major variables affecting pulmonary function were age and cigarette smoking. When the effects of age and smoking were controlled in an age-specific, two-way analysis of variance, no consistent effects of total dust exposure were detectable in these workers. This study provided no evidence that exposure to total dust under the conditions pertaining in the contemporary carbon black industry had detrimental effects on the pulmonary function of men employed in the production and handling of this product.

  14. Cycling of Black Carbon in the Ocean

    NASA Astrophysics Data System (ADS)

    Coppola, Alysha I.; Druffel, Ellen R. M.

    2016-04-01

    Black Carbon (BC) is a byproduct of biomass burning and fossil fuel combustion and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial timescales in the world's oceans has remained unknown. Here, we quantified dissolved BC (DBC) in marine dissolved organic carbon (DOC) isolated by solid phase extraction (SPE) and determined its residence time. The range of DBC structures and 14C ages indicates that DBC is not homogeneous in the ocean. We conclude that there are at least two distinct pools of marine DBC, a younger pool that cycles on centennial timescales and an ancient pool that cycles on >105 year timescales.

  15. Black carbon characterization in Quebec black spruce forests

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, Laure; Quideau, Sylvie; Wasylishen, Roderick; MacKenzie, M. Derek

    2014-05-01

    Black carbon (BC), an important component of the global soil carbon pool, is a major by-product of wildfires in Quebec black spruce forests. However, BC characteristics vary depending on the environmental conditions under which it is formed and this may further affect its resistance to degradation. The objective of this study was to characterize the chemical and physical properties of BC formed under variable fire severity to assess its potential for recalcitrance as a passive carbon pool. Samples (n = 267) of BC produced by early season wildfires in 2005-2007 were collected from the surface of black spruce forest floors to cover the range of severity encountered in these fire-affected forests. Representative samples (n = 33) were then analyzed using elemental analysis, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy and surface area analysis (BET method). Properties of BC sampled in the field were compared with those of samples produced under a range of controlled formation conditions in the laboratory. The NMR spectra of the BC collected on sites affected by low fire severity showed a distribution of total intensity between the different spectral regions very similar to those of unburned fuels, and were dominated by peaks indicative of cellulose, while spectra for BC from higher fire severity sites were dominated by a broad peak assigned to aromatic carbons. Atomic H/C and O/C ratios decreased along the fire severity gradient, confirming that increasing severity was associated with an increase in condensation. By comparing field- to laboratory-produced samples, we concluded that the temperature of formation in the field ranged between 75 and 250 ° C. In all analyzed BC samples, the fraction of aromatic carbon:total carbon was low, suggesting that the freshly produced BC in this boreal forest environment may be susceptible to rapid physical alteration and chemical degradation. Nevertheless, it is important to highlight

  16. Black Carbon characterization in Quebec black spruce forests

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, L. N.; Wasylishen, R. E.; MacKenzie, M. D.; Quideau, S. A.

    2012-04-01

    Black carbon (BC), the solid carbonaceous residue of incomplete combustion, is a major by-product of wildfires in Quebec black spruce forests. Because of its estimated recalcitrance, it is considered a valuable pool in the global carbon cycle. However, BC characteristics, and more specifically its resistance to degradation depend on its conditions of formation. The objective of this study was to characterize BC chemical and physical properties under varying fire severities in order to assess its potential for recalcitrance as a passive carbon pool. Fresh BC samples from the forest floor were collected in 2010 from Quebec black spruce forests stands that had burnt 3-5 years prior. Fire severity was assessed at each sampling location and a total of 33 samples were selected to cover the range of severity encountered in these burnt forests. Samples were further analyzed for aromaticity and porosity using elemental and proximate analyses, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM) and surface area (SA) analysis. They were then compared to BC samples produced under controlled conditions in the laboratory (lab-BC). The 13C NMR spectra of the BC collected on low fire severity sites showed a distribution of total intensity between the different spectral regions very similar to those of unburnt fuels. They were generally dominated by a peak at 74 ppm indicative of cellulose. On the other hand, 13C NMR spectra obtained for BC from high fire severity sites were dominated by peaks from aromatic carbons. When compared to the lab-BC NMR spectra, we concluded that the temperature of formation for the 33 analyzed samples ranged between 75°C and 250°C and that pyrolysis conditions prevailed, which points towards BC formation by a smouldering fire. Atomic ratio values (H/C = [1.36-0.77]; O/C = [0.75-0.30]) decreased with increasing fire severity and were in agreement with the results from 13C NMR spectroscopy. Finally, the

  17. Relating urban airborne particle concentrations to shipping using carbon based elemental emission ratios

    NASA Astrophysics Data System (ADS)

    Johnson, Graham R.; Juwono, Alamsyah M.; Friend, Adrian J.; Cheung, Hing-Cho; Stelcer, Eduard; Cohen, David; Ayoko, Godwin A.; Morawska, Lidia

    2014-10-01

    This study demonstrates a novel method for testing the hypothesis that variations in primary and secondary particle number concentration (PNC) in urban air are related to residual fuel oil combustion at a coastal port lying 30 km upwind, by examining the correlation between PNC and airborne particle composition signatures chosen for their sensitivity to the elemental contaminants present in residual fuel oil. Residual fuel oil combustion indicators were chosen by comparing the sensitivity of a range of concentration ratios to airborne emissions originating from the port. The most responsive were combinations of vanadium and sulphur concentration ([S], [V]) expressed as ratios with respect to black carbon concentration ([BC]). These correlated significantly with ship activity at the port and with the fraction of time during which the wind blew from the port. The average [V] when the wind was predominantly from the port was 0.52 ng m-3 (87%) higher than the average for all wind directions and 0.83 ng m-3 (280%) higher than that for the lowest vanadium yielding wind direction considered to approximate the natural background. Shipping was found to be the main source of V impacting urban air quality in Brisbane. However, contrary to the stated hypothesis, increases in PNC related measures did not correlate with ship emission indicators or ship traffic. Hence at this site ship emissions were not found to be a major contributor to PNC compared to other fossil fuel combustion sources such as road traffic, airport and refinery emissions.

  18. ARM Airborne Carbon Measurements VI (ACME VI) Science Plan

    SciTech Connect

    Biraud, S

    2015-12-01

    From October 1 through September 30, 2016, the Atmospheric Radiation Measurement (ARM) Aerial Facility will deploy the Cessna 206 aircraft over the Southern Great Plains (SGP) site, collecting observations of trace-gas mixing ratios over the ARM’s SGP facility. The aircraft payload includes two Atmospheric Observing Systems, Inc., analyzers for continuous measurements of CO2 and a 12-flask sampler for analysis of carbon cycle gases (CO2, CO, CH4, N2O, 13CO2, 14CO2, carbonyl sulfide, and trace hydrocarbon species, including ethane). The aircraft payload also includes instrumentation for solar/infrared radiation measurements. This research is supported by the U.S. Department of Energy’s ARM Climate Research Facility and Terrestrial Ecosystem Science Program and builds upon previous ARM Airborne Carbon Measurements (ARM-ACME) missions. The goal of these measurements is to improve understanding of 1) the carbon exchange at the SGP site, 2) how CO2 and associated water and energy fluxes influence radiative forcing, convective processes and CO2 concentrations over the SGP site, and 3) how greenhouse gases are transported on continental scales.

  19. Stratospheric geoengineering with black carbon aerosols

    NASA Astrophysics Data System (ADS)

    Kravitz, Benjamin S.

    I use a general circulation model of Earth's climate to simulate stratospheric geoengineering with black carbon aerosols, varying the altitude of injection, initial particle size, and whether the deposited black carbon modifies ground albedo. 1 Tg of black carbon aerosols injected into the stratosphere each year will cause significant enough surface cooling to negate anthropogenic warming if the aerosols are small (r=0.03 mum) or if the aerosols are injected into the middle stratosphere, although using small aerosols causes large regional cooling effects that would be catastrophic to agriculture. The aerosols cause significant stratospheric heating, resulting in stratospheric ozone destruction and circulation changes, most notably an increase in the Northern Hemisphere polar jet, which forms an Arctic ozone hole and forces a positive mode of the Arctic Oscillation. The hydrologic cycle is perturbed, specifically the summer monsoon system of India, Africa, and East Asia, resulting in monsoon precipitation collapse. Global primary productivity is decreased by 35.5% for the small particle case. Surface cooling causes some sea ice regrowth, but not at statistically significant levels. All of these climate impacts are exacerbated for small particle geoengineering, with high altitude geoengineering with the default particle size (r=0.08 mum) causing a reasonable amount of cooling, and large particle (r=0.15 mum) geoengineering or particle injection into the lower stratosphere causing few of these effects. The modification of ground albedo by the soot particles slightly perturbs the radiative budget but does not cause any distinguishable climate effects. The cheapest means we investigated for placing 1 Tg of black carbon aerosols into the stratosphere by diesel fuel combustion would cost 1.4 trillion initially and 541 billion annual, or 2.0% and 0.8% of GDP, respectively. The additional carbon dioxide released from combusting diesel to produce these aerosols is about 1

  20. Black pine (Pinus nigra) barks as biomonitors of airborne mercury pollution.

    PubMed

    Chiarantini, Laura; Rimondi, Valentina; Benvenuti, Marco; Beutel, Marc W; Costagliola, Pilario; Gonnelli, Cristina; Lattanzi, Pierfranco; Paolieri, Mario

    2016-11-01

    Tree barks are relevant interfaces between plants and the external environment, and can effectively retain airborne particles and elements at their surface. In this paper we have studied the distribution of mercury (Hg) in soils and in black pine (Pinus nigra) barks from the Mt. Amiata Hg district in southern Tuscany (Italy), where past Hg mining and present-day geothermal power plants affect local atmospheric Hg concentration, posing serious environmental concerns. Barks collected in heavily Hg-polluted areas of the district display the highest Hg concentration ever reported in literature (8.6mg/kg). In comparison, barks of the same species collected in local reference areas and near geothermal power plants show much lower (range 19-803μg/kg) concentrations; even lower concentrations are observed at a "blank" site near the city of Florence (5-98μg/kg). Results show a general decrease of Hg concentration from bark surface inwards, in accordance with a deposition of airborne Hg, with minor contribution from systemic uptake from soils. Preliminary results indicate that bark Hg concentrations are comparable with values reported for lichens in the same areas, suggesting that tree barks may represent an additional useful tool for biomonitoring of airborne Hg. PMID:27341111

  1. COCAP - A compact carbon dioxide analyser for airborne platforms

    NASA Astrophysics Data System (ADS)

    Kunz, Martin; Lavrič, Jošt V.; Jeschag, Wieland; Bryzgalov, Maksym; Hök, Bertil; Heimann, Martin

    2014-05-01

    Airborne platforms are a valuable tool for atmospheric trace gas measurements due to their capability of movement in three dimensions, covering spatial scales from metres to thousands of kilometres. Although crewed research aircraft are flexible in payload and range, their use is limited by high initial and operating costs. Small unmanned aerial vehicles (UAV) have the potential for substantial cost reduction, but require lightweight, miniaturized and energy-efficient scientific equipment. We are developing a COmpact Carbon dioxide analyser for Airborne Platforms (COCAP). It contains a non-dispersive infrared CO2sensor with a nominal full scale of 3000 μmol/mol. Sampled air is dried with magnesium perchlorate before it enters the sensor. This enables measurement of the dry air mole fraction of CO2, as recommended by the World Meteorological Organization. During post-processing, the CO2 measurement is corrected for temperature and pressure variations in the gas line. Allan variance analysis shows that we achieve a precision of better than 0.4 μmol/mol for 10 s averaging time. We plan to monitor the analyser's stability during flight by measuring reference air from a miniature gas tank in regular intervals. Besides CO2, COCAP measures relative humidity, temperature and pressure of ambient air. An on-board GPS receiver delivers accurate timestamps and allows georeferencing. Data is both stored on a microSD card and simultaneously transferred over a wireless serial interface to a ground station for real-time review. The target weight for COCAP is less than 1 kg. We deploy COCAP on a commercially available fixed-wing UAV (Bormatec Explorer) with a wingspan of 2.2 metres. The UAV has high payload capacity (2.5 kg) as well as sufficient space in the fuselage (80x80x600 mm3). It is built from a shock-resistant foam material, which allows quick repair of minor damages in the field. In case of severe damage spare parts are readily available. Calculations suggest that the

  2. New Potential Sources for Black Onaping Carbon

    NASA Technical Reports Server (NTRS)

    Bunch, T. E.; Becker, L.; Schultz, P. H.; Wolbach, W. S.

    1997-01-01

    One intriguing and important issue of the Sudbury Structure concerns the source of the relatively large amount of C in the Onaping Formation Black member. This dilemma was recently addressed, and the conclusion was reached that an impactor could not have delivered all of the requisite C. Becker et al. have suggested that much of the C came from the impactor and reported the presence of interstellar He "caged" inside some fullerenes that may have survived the impact. So, conceivably, the C inventory in the Sudbury Structure comes from both target and impactor materials, although the known target rocks have little C. We discuss here the possibility of two terrestrial sources for at least some of the C: (1) impact evaporation/dissociation of C from carbonate target rocks and (2) the presence of heretofore-unrecognized C-rich (up to 26 wt%) siliceous "shale," fragments, which are found in the upper, reworked Black member. Experimental: Hypervelocity impact of a 0.635-diameter Al projectile into dolomite at 5.03 km/s (performed at the Ames Research Center vertical gun range) produced a thin, black layer (= 0.05 mm thick) that partially lined the crater and coated impactor remnants. Scanning electronic microscope (SEM) imagery shows this layer to be spongelike on a submicron scale and Auger spectroscopic analyses yield: 33% C, 22% Mg, 19% 0, and 9% Al (from the projectile). Elemental mapping shows that all of the available 0 is combined with Ca and Mg, Al is not oxidized, and C is in elemental form. Dissociation efficiency of C from CO2 is estimated to be <10% of crater volume. Raman spectroscopy indicates that the C is highly disorganized graphite. Another impact experiment [4] also produced highly disordered graphite from a limestone target (reducing collector), in addition to small amounts of diamond/lonsdaleite/chaoite (oxidizing collector). These experiments confirm the reduction of C from carbonates in impact vapor plumes. Observational: SEM observations and

  3. Qualitative determination of carbon black in food products.

    PubMed

    Miranda-Bermudez, E; Belai, N; Harp, B Petigara; Yakes, B J; Barrows, J N

    2012-01-01

    Carbon black (C.I. 77266) is an insoluble pigment produced by the partial combustion of hydrocarbons. The pigment is known by several synonyms, including vegetable carbon, lamp black and carbon ash, that correspond to the raw materials and methods used for its production. Vegetable carbon (E153) is permitted for use in colouring food in the European Union. The US Food and Drug Administration (USFDA) has not approved the use of any type of carbon black for colouring food, although the agency batch certifies the pigment as D&C Black No. 2 for use in colouring certain cosmetics. Since carbon black (as vegetable carbon) may be present in food products offered for import into the United States, the USFDA's district laboratories need a qualitative analytical method for determining its presence. We have developed an extraction method for this purpose. A sample is broken down and dissolved with nitric acid. The resulting solution is filtered and treated with hydrochloric acid to dissolve any black iron oxide also present as a colour additive. A black residue remaining on the filter paper indicates the presence of carbon black in the food. We confirmed the presence of carbon black in residues from several standards and food products using Raman spectroscopy. The limit of detection for this method is 0.0001%. PMID:22035229

  4. Phase Behavior of Dilute Carbon Black Suspensions and Carbon Black Stabilized Emulsions

    NASA Astrophysics Data System (ADS)

    Godfrin, Michael; Tiwari, Ayush; Bose, Arijit; Tripathi, Anubhav

    2014-11-01

    We use para-amino benzoic acid terminated carbon black (CB) as a tunable model particulate material to study the effect of inter-particle interactions on phase behavior and steady shear stresses in suspensions and particle-stabilized emulsions. We modulate inter-particle interactions by adding NaCl to the suspension, thus salting surface carboxylate groups. Surprisingly, yield stress behavior emerged at a volume fraction of CB as low as ϕCB = 0.008, and gel behavior was observed at ϕCB >0.05, well below the percolation threshold for non-interacting particles. The yield stress was found to grow rapidly with carbon black concentration suggesting that salt-induced hydrophobicity leads to strong inter-particle interactions and the formation of a network at low particle concentrations. The yield stresses of CB-stabilized emulsions also grows rapidly with carbon black concentrations, implying that inter-droplet interactions can be induced through the tuning of carbon black concentration in emulsion systems. Emulsions stabilized by ionic surfactants show no inter-droplet interactions. In contrast, oil droplets in the CB-stabilized emulsion move collectively or are immobilized because of an interconnected CB network in the aqueous phase.

  5. Black Carbon, Aerosols, and the Tooth Fairy

    NASA Astrophysics Data System (ADS)

    Buseck, P. R.; Adachi, K.; Posfai, M.

    2012-12-01

    Black carbon (BC) is widely cited in the atmospheric literature as a major aerosol particle type with significant effects on climate warming. Several analytical techniques are used for its determination, primarily through optical absorption measurements. A recently developed and widely used method is single particle soot photometry (SP2). During attempts to obtain reliable BC samples for study using transmission electron microscopy (TEM), it became apparent that no such samples exist. Instead, surrogate materials such as graphite, fullerene, Aquadag, and perhaps other things are used as calibration standards. It became rapidly evident that BC is an inferred rather than actual, identifiable substance with distinct material properties other than its absorption spectrum and refractory character (accounting for the subset of refractory black carbon, or rBC). Since climate effects depend on optical properties, and these are estimated for BC, it may not be critical at this time whether or not it is a discrete material. However, the same term is also used by other environmental communities for things that are distinctly different. Such imprecision in terms can lead to unnecessary confusion. The situation is summarized in the Table. We propose that 1) the term BC should be restricted to light-absorbing refractory carbonaceous matter of uncertain character and 2) the uncertainty be stated explicitly. We also propose a more precise definition for soot as a specific material, which we call ns-soot, where "ns" refers to carbon nanospheres. We define ns-soot as particles that consist of nanospheres, typically with diameters <100 nm, that possess distinct structures of concentrically wrapped, graphene-like layers of carbon and with grape-like (acinoform) morphologies.;

  6. Brown Carbon: Results From Ground and Airborne Studies

    NASA Astrophysics Data System (ADS)

    Weber, R. J.; Forrister, H.; Liu, J.; Nenes, A.

    2015-12-01

    Brown carbon (BrC) is directly measured with high sensitivity by isolating it from black carbon in aerosol extracts and using long path wave-guide spectrophotometry. Ambient measurements by this approach show that BrC is pervasive and can be found in almost all locations, ranging from urban environments to remote continental sites and upper reaches of the free troposphere. Biomass burning appears to be the major source in many urban and rural locations, but other sources of incomplete combustion, such as vehicle emissions in urban environments also play a role. Secondary aerosols not associated with combustion sources may also contribute, but are likely of lesser importance. Studies of ambient wildfire smoke plumes show that BrC levels decrease as it ages, with a half-life of approximately 10 hours. However, a small fraction of the emitted BrC is stable and may account for much of the BrC observed throughout the atmosphere due to widely dispersed and ubiquitous smoke. A radiative transfer model indicates that this background BrC reduced US continental TOA forcing by 20 percent. Human health studies point to similar chemical components linked to BrC (i.e., HULIS), of this same ubiquitous smoke, as a significant source of adverse cardiorespiratory effects. This talk will summarize findings on BrC sources, transformations and estimates of environmental effects based on bulk measurements.

  7. Influence of public transport in black carbon

    NASA Astrophysics Data System (ADS)

    Vasquez, Y.; Oyola, P.; Gramsch, E. V.; Moreno, F.; Rubio, M.

    2013-05-01

    As a consequence of poor air quality in Santiago de Chile, several measures were taken by the local authorities to improve the environmental conditions and protect the public health. In year 2005 the Chilean government implemented a project called "Transantiago" aimed to introduce major modifications in the public transportation system. The primary objectives of this project were to: provide an economically, socially and environmentally sustainable service and improve the quality of service without increasing fares. In this work we evaluate the impact of the Transantiago system on the black carbon pollution along four roads directly affected by the modification to the transport system. The black carbon has been used to evaluate changes in air quality due to changes in traffic. The assessment was done using measurements of black carbon before Transantiago (June-July 2005) and after its implementation (June-July 2007). Four sites were selected to monitor black carbon at street levels, one site (Alameda) that represents trunk-bus streets, i.e., buses crossing the city through main avenues. Buses using these streets had an important technological update with respect to 2005. Two streets (Usach and Departamental) show a mixed condition, i.e., they combine feeder and trunk buses. These streets combine new EURO III buses with old buses with more than 3 years of service. The last street (Eliodoro Yañez) represent private cars road without public transportation and did not experience change. Hence, the results from the years 2005 and 2007 can be directly compared using an appropriate methodology. To ensure that it was not the meteorological conditions that drive the trends, the comparison between year 2005 and 2007 was done using Wilcoxon test and a regression model. A first assessment at the four sites suggested a non decrease in black carbon concentration from 2005 to 2007, except for Alameda. A first statistical approach confirmed small increases in BC in Usach and E

  8. Respiratory health effects of carbon black: a survey of European carbon black workers.

    PubMed Central

    Gardiner, K; Trethowan, N W; Harrington, J M; Rossiter, C E; Calvert, I A

    1993-01-01

    A study population of 3086 employees was identified in 18 carbon black production plants in seven European countries. Respiratory health questionnaires, spirometry, and chest radiographs were used to estimate effects on health and personal monitoring procedures were employed to measure current exposure to inspirable and respirable dust along with sulphur and carbon monoxide. The low concentrations of gaseous contaminants made the generation of their current and cumulative exposure indices impossible. Low responses from some plants restricted the final analysis to 1742 employees in 15 plants (81% response rate) for respiratory symptoms and spirometry, and 1096 chest radiographs from 10 plants (74% response rate). In total, 1298 respirable and 1317 inspirable dust samples, as well as 1301 sulphur dioxide and 1322 carbon monoxide samples were collected. This study is the first to include a comprehensive and concurrent assessment of occupational exposure to carbon black dust and its associated gaseous contaminants. Cough, sputum, and the symptoms of chronic bronchitis were found to be associated with increasing indices of current exposure. Lung function tests also showed small decreases in relation to increasing dust exposure in both smokers and non-smokers. Nearly 25% of the chest radiographs showed small opacities of category 0/1 or greater. These were strongly associated with indices of cumulative dust exposure. The findings are consistent with a non-irritant effect of carbon black dust on the airways combined with dust retention in the lungs. Further cross sectional studies are planned to investigate whether long term exposure to carbon black dust causes damage to the lung parenchyma. PMID:8280639

  9. Does carbon black disaggregate in lung fluid? A critical assessment.

    PubMed

    Levy, Len; Chaudhuri, Ishrat S; Krueger, Nils; McCunney, Robert J

    2012-10-15

    Carbon black is an industrially produced particulate form of nearly pure elemental carbon. The basic building blocks of carbon black are (1) primary particles, minute pieces of matter with defined physical boundaries; (2) aggregates, collections of strongly bound or fused particles; and (3) agglomerates, collections of weakly bound aggregates. Industrial carbon black is produced within a closed reactor where the primary particles form aggregates, which become the indivisible entities of carbon black. These aggregates then form agglomerates, which are the typical form of carbon black in commerce. Carbon black is often used in in vitro and in vivo particle toxicology investigations as a reference nanoparticle. The toxicology studies often report the sizes of the primary particles but rarely the sizes of the aggregates or agglomerates. It appears in many cases that there is a limited understanding of the fact that carbon black typically does not exist as primary particles but instead exists as aggregates and agglomerates. Moreover, many toxicology studies manipulate carbon black particles in order to disperse them so that the form of carbon black used in these toxicology studies may be substantially different from the form that may be encountered in the workplace environment. Since the main exposure route for carbon black is inhalation, the question arose as to whether inhaled carbon black may deagglomerate or disaggregate to either smaller aggregates or primary particles when in contact with lung fluids. This question relates to the concern that there may be additional hazards of smaller particles, such as their ability to translocate to tissues and organs beyond the lung and the ability to pass through the blood-brain barrier. The purpose of this assessment is to review the existing literature for evidence as to whether carbon black deagglomerates or disaggregates into smaller aggregates or primary particles when in contact with lung fluid. On the basis of a review

  10. First Airborne Laser Remote Measurements of Atmospheric Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Browell, E. V.; Dobbs, M. E.; Dobler, J.; Kooi, S.; Choi, Y.; Harrison, F. W.; Moore, B.; Zaccheo, T. S.

    2008-12-01

    A unique, multi-frequency, single-beam, laser absorption spectrometer (LAS) that operates at 1.57 μm has been developed for a future space-based mission to determine the global distribution of sources and sinks of atmospheric carbon dioxide (CO2). A prototype of the space-based LAS system was developed by ITT, and it has been successfully flight tested in five airborne campaigns conducted in different geographic regions over the last three years. Flight tests were conducted over Oklahoma, Michigan, New Hampshire, and Virginia under a wide range of atmospheric conditions. Remote LAS measurements were compared to high-quality in situ measurements obtained from instrumentation on the same aircraft on spirals under the ground track of the LAS. LAS flights were conducted over a wide range of land and water reflectances and in the presence of scattered clouds. An extensive data set of CO2 measurements has been obtained for evaluating the LAS performance. LAS CO2 measurements with a signal-to-noise in excess of 250 were obtained for a 1-s average over land and for a 10-s average over water. Absolute comparisons of CO2 remote and in situ measurements showed agreement over a range of altitudes to better than 2 percent. LAS oxygen (O2) measurements, which are needed to convert LAS CO2 density measurements to CO2 mixing ratios (XCO2), have been made in the 1.26-μm region in horizontal ground-based experiments and in initial flight tests. Details of flight test campaigns and measured versus modeled results are presented in this paper.

  11. Double-walled carbon nanotubes synthesized using carbon black as the dot carbon source

    NASA Astrophysics Data System (ADS)

    Chen, Zhi-Gang; Li, Feng; Ren, Wen-Cai; Cong, Hongtao; Liu, Chang; Qing Lu, Gao; Cheng, Hui-Ming

    2006-07-01

    Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dot carbon source by a semi-continuous hydrogen arc discharge process. High-resolution transmission electron microscopy (HRTEM) observations revealed that most of the tubes were DWNTs with outer and inner diameters in the range of 2.67-4 nm and 1.96-3.21 nm, respectively. Most of the DWNTs were in a bundle form of about 10-30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis (TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM) and TEM characterizations. It was found that carbon black as the dot carbon source could be easy controlled to synthesize one type of nanotube. A simple process combining oxidation and acid treatment to purify the DWNT bundles was used without damaging the bundles. The structure of carbon black, as the key element for influencing purity, bundle formation and purification of DWNTs, is discussed.

  12. Surface Chemistry and Water Dispersability of Carbon Black Materials

    SciTech Connect

    Contescu, Cristian I; Baker, Frederick S; Burchell, Timothy D

    2006-01-01

    Formulation of water-stable carbon black dispersions is a double-sided task, which requires selection of a proper dispersing agents and matching it with the properties of a specific carbon black. Among other properties that affect water dispersability of carbon blacks (particle size, surface area, and aggregate structure), surface chemistry plays a prime-order role. We have characterized physical and chemical properties of several carbon black materials, and correlated them with the stability of dispersions formed with ionic and non-ionic surfactants. In particular, chemical characterization of surface functional groups on carbon blacks based on potentiometric titration measurements (pKa spectra) provided a comprehensive picture of pH effects on dispersion stability. The results obtained were complemented by information from physical characterization methods, such as XPS and FTIR. The selection of a suitable dispersing agent able to withstand large pH variations will be discussed.

  13. Thermal properties of carbon black aqueous nanofluids for solar absorption

    NASA Astrophysics Data System (ADS)

    Han, Dongxiao; Meng, Zhaoguo; Wu, Daxiong; Zhang, Canying; Zhu, Haitao

    2011-07-01

    In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  14. A comparison of black carbon measurement methods for combustion sources

    NASA Astrophysics Data System (ADS)

    Holder, A. L.; Pavlovic, J.; Yelverton, T.; Hagler, G.; Aurell, J.; Ebersviller, S.; Seay, B.; Jetter, J.; Gullett, B.; Hays, M. D.

    2015-12-01

    Black carbon is an important short-term climate forcer that has been linked with adverse health effects. Multiple black carbon measurement methodologies exist, but no standard measurement method or calibration material has been agreed upon. Moreover, the U.S. Environmental Protection Agency uses elemental carbon in its ambient monitoring networks and in its emissions inventory, assuming that elemental carbon is equivalent to black carbon. Instrument comparisons with ambient aerosols have demonstrated considerable differences between black carbon and elemental carbon, as well as among different black carbon measurements. However, there have been few published comparable studies for source emissions. We used multiple measurement methods to quantify black carbon and elemental carbon emissions from a range of combustion sources (diesel gensets, coal fired boilers, prescribed fires and cookstoves) emitting particles of varying composition and physical characteristics. The ratio of black carbon to elemental carbon (BC/EC) ranged from 0.50 to 2.8 and depended upon the combustion source. The greatest agreement was observed for emissions from cookstoves (BC/EC = 1.1 ± 0.3). The largest differences were seen for emissions from large stationary diesel genset (BC/EC = 2.3 ± 0.5) and were most pronounced when a diesel particulate filter was used (BC/EC 2.5 ± 0.6). This suggests that this source category may be underrepresented in emissions inventories based on elemental carbon. Black carbon concentrations derived from filter-based attenuation were highly correlated with photo-acoustic absorption measurements, but were generally 50% greater. This is likely due to the choice of calibration factor, which is currently ambiguously defined. These results highlight the importance of developing a standard calibration material to improve comparability among measurements.

  15. Cycling of black carbon in the ocean

    NASA Astrophysics Data System (ADS)

    Coppola, Alysha I.; Druffel, Ellen R. M.

    2016-05-01

    Black carbon (BC) is a by-product of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial time scales in the world oceans has remained unknown. Here we quantified dissolved BC (DBC) in marine dissolved organic carbon isolated by solid phase extraction at several sites in the world ocean. We find that DBC in the Atlantic, Pacific, and Arctic oceans ranges from 1.4 to 2.6 μM in the surface and is 1.2 ± 0.1 μM in the deep Atlantic. The average 14C age of surface DBC is 4800 ± 620 14C years and much older in a deep water sample (23,000 ± 3000 14C years). The range of DBC structures and 14C ages indicates that DBC is not homogeneous in the ocean. We show that there are at least two distinct pools of marine DBC, a younger pool that cycles on centennial time scales and an ancient pool that cycles on >105 year time scales.

  16. New Potential Sources for Black Onaping Carbon

    NASA Technical Reports Server (NTRS)

    Bunch, T. E.; Becker, L.; Schultz, P. H.; Wolbach, W. S.

    1997-01-01

    One intriguing and important issue of the Sudbury Structure concerns the source of the relatively large amount of C in the Onaping Formation Black member. This dilemma was recently addressed, and the conclusion was reached that an impactor could not have delivered all of the requisite C. Becker et al. have suggested that much of the C came from the impactor and reported the presence of interstellar He "caged" inside some fullerenes that may have survived the impact. So, conceivably, the C inventory in the Sudbury Structure comes from both target and impactor materials, although the known target rocks have little C. We discuss here the possibility of two terrestrial sources for at least some of the C: (1) impact evaporation/dissociation of C from carbonate target rocks and (2) the presence of heretofore-unrecognized C-rich (up to 26 wt%) siliceous "shale," fragments, which are found in the upper, reworked Black member. Experimental: Hypervelocity impact of a 0.635-diameter Al projectile into dolomite at 5.03 km/s (performed at the Ames Research Center vertical gun range) produced a thin, black layer (= 0.05 mm thick) that partially lined the crater and coated impactor remnants. Scanning electronic microscope (SEM) imagery shows this layer to be spongelike on a submicron scale and Auger spectroscopic analyses yield: 33% C, 22% Mg, 19% 0, and 9% Al (from the projectile). Elemental mapping shows that all of the available 0 is combined with Ca and Mg, Al is not oxidized, and C is in elemental form. Dissociation efficiency of C from CO2 is estimated to be <10% of crater volume. Raman spectroscopy indicates that the C is highly disorganized graphite. Another impact experiment [4] also produced highly disordered graphite from a limestone target (reducing collector), in addition to small amounts of diamond/lonsdaleite/chaoite (oxidizing collector). These experiments confirm the reduction of C from carbonates in impact vapor plumes. Observational: SEM observations and

  17. Geolocating Russian sources for Arctic black carbon

    NASA Astrophysics Data System (ADS)

    Cheng, Meng-Dawn

    2014-08-01

    To design and implement an effective emission control strategy for black carbon (BC), the locations and strength of BC sources must be identified. Lack of accurate source information from the Russian Federation has created difficulty for a range of research and policy activities in the Arctic because Russia occupies the largest landmass in the Arctic Circle. A project was initiated to resolve emission sources of BC in the Russian Federation by using the Potential Source Contribution Function (PSCF). It used atmospheric BC data from two Arctic sampling stations at Alert Nunavut, Canada, and Tiksi Bay, Russia. The geographical regions of BC emission sources in Russia were identified and summarized as follows: (1) a region surrounding Moscow, (2) regions in Eurasia stretching along the Ural Mountains from the White Sea to the Black Sea, and (3) a number of scattered areas from western Siberia to the Russian Far East. Particulate potassium ions, non-marine sulfate, and vanadium were used to assist in resolving the source types: forest fire/biomass burning, coal-fired power plant, and oil combustion. Correlating these maps with the BC map helped to resolve source regions of BC emissions and connect them to their corresponding source types. The results imply that a region south of Moscow and another north of the Ural Mountains could be significant BC sources, but none of the grid cells in these regions could be linked to forest fires, oil combustion, or coal-fired power plants based on these three markers.

  18. Black Carbon Measurements in SOLVE-2

    NASA Technical Reports Server (NTRS)

    Kok, Gregory L.; Baumgardner, Darrel R.

    2004-01-01

    Droplet Measurement Technologies (DMT), under funding from NASA s Radiation Sciences Program, participated in the SOLVE II field campaign with measurements of light absorbing particles (black carbon and metals). These measurements were made with the Single Particle Soot Photometer (SP-2) on the NASA DC-8. The SP-2 is a new measurement technique that was developed under the SBIR program with funding from the Office of Naval Research. The original instrument suite for the DC-8 did not include the SP-2 and its addition and operation during SOLVE II was intended solely as a means to test its functionality and prepare it for future flight operations. For this reason it required several flights in the early stages of the project to tune its operation and fix some problems that arose. During the flights of January 26, 29, and 30, and February 2, 4 and 6, however, it worked as designed and acquired credible data.

  19. Black carbon aerosols in urban central China

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaolin; Rao, Ruizhong; Huang, Yinbo; Mao, Mao; Berg, Matthew J.; Sun, Wenbo

    2015-01-01

    The first ever (to our knowledge), year-round measurements of Black Carbon (BC) aerosols in Hefei, an urban site of central China, from June 2012 to May 2013 are performed. The aim of this paper is to evaluate the black carbon in Hefei in terms of seasonal, monthly and diurnal variations, including their source identification. The annual mean BC mass concentration MBC is found to be 3.5±2.5 μg m-3 in Hefei, while the aerosol optical depth shows a yearly average value of ~0.6. The seasonality of MBC depicts minimum values in the summer, moderate levels in the spring and fall, and maximum in the winter. The monthly average values of MBC vary threefold, ranging from the lowest average value of 2.0±1.0 μg m-3 in July to the highest 6.0±2.6 μg m-3 during January. Diurnal variations exhibit two BC peaks, corresponding to the morning and evening rush hours. Higher median BC concentrations are observed during haze episodes compared with non-haze periods, although low MBC is sometimes observed for high visibility, which is probably indicative of the aerosol scattering dominating diminished visibility. Based on trajectory analyses, the haze BC pollutions are mostly classified into three types from local areas, long-range transport from the Yangtze Delta, and transport from the North China Plain. The median MBC values for haze groups attributed to biomass burning from MODIS wildfire maps are higher than related groups that are not, which is indicative of the significant enhancement of BC aerosols due to agricultural biomass burning. The study suggests that aerosol absorption contributes more to the observed haze episodes in fall compared to other seasons.

  20. Airborne Measurements in Support of the NASA Atmospheric Carbon and Transport - America (ACT-America) Mission

    NASA Technical Reports Server (NTRS)

    Meadows, Byron; Davis, Ken; Barrick, John; Browell, Edward; Chen, Gao; Dobler, Jeremy; Fried, Alan; Lauvaux, Thomas; Lin, Bing; McGill, Matt; Miles, Natasha; Nehrir, Amin; Obland, Michael; O'Dell, Chris; Sweeney, Colm; Yang, Melissa

    2015-01-01

    NASA announced the research opportunity Earth Venture Suborbital -2 (EVS-2) mission in support of the NASA's science strategic goals and objectives in 2013. Penn State University, NASA Langley Research Center (LaRC), and other academic institutions, government agencies, and industrial companies together formulated and proposed the Atmospheric Carbon and Transport -America (ACT -America) suborbital mission, which was subsequently selected for implementation. The airborne measurements that are part of ACT-America will provide a unique set of remote and in-situ measurements of CO2 over North America at spatial and temporal scales not previously available to the science community and this will greatly enhance our understanding of the carbon cycle. ACT -America will consist of five airborne campaigns, covering all four seasons, to measure regional atmospheric carbon distributions and to evaluate the accuracy of atmospheric transport models used to assess carbon sinks and sources under fair and stormy weather conditions. This coordinated mission will measure atmospheric carbon in the three most important regions of the continental US carbon balance: Northeast, Midwest, and South. Data will be collected using 2 airborne platforms (NASA Wallops' C-130 and NASA Langley's B-200) with both in-situ and lidar instruments, along with instrumented ground towers and under flights of the Orbiting Carbon Observatory (OCO-2) satellite. This presentation provides an overview of the ACT-America instruments, with particular emphasis on the airborne CO2and backscatter lidars, and the, rationale, approach, and anticipated results from this mission.

  1. Airborne Measurements in Support of the NASA Atmospheric Carbon and Transport - America (ACT-America) Mission

    NASA Astrophysics Data System (ADS)

    Meadows, B.; Davis, K.; Barrick, J. D. W.; Browell, E. V.; Chen, G.; Dobler, J. T.; Fried, A.; Lauvaux, T.; Lin, B.; McGill, M. J.; Miles, N. L.; Nehrir, A. R.; Obland, M. D.; O'Dell, C.; Sweeney, C.; Yang, M. M.

    2015-12-01

    NASA announced the research opportunity Earth Venture Suborbital - 2 (EVS-2) mission in support of the NASA's science strategic goals and objectives in 2013. Penn State University, NASA Langley Research Center (LaRC), and other academic institutions, government agencies, and industrial companies together formulated and proposed the Atmospheric Carbon and Transport - America (ACT - America) suborbital mission, which was subsequently selected for implementation. The airborne measurements that are part of ACT-America will provide a unique set of remote and in-situ measurements of CO2 over North America at spatial and temporal scales not previously available to the science community and this will greatly enhance our understanding of the carbon cycle. ACT - America will consist of five airborne campaigns, covering all four seasons, to measure regional atmospheric carbon distributions and to evaluate the accuracy of atmospheric transport models used to assess carbon sinks and sources under fair and stormy weather conditions. This coordinated mission will measure atmospheric carbon in the three most important regions of the continental US carbon balance: Northeast, Midwest, and South. Data will be collected using 2 airborne platforms (NASA Wallops' C-130 and NASA Langley's B-200) with both in-situ and lidar instruments, along with instrumented ground towers and under flights of the Orbiting Carbon Observatory (OCO-2) satellite. This presentation provides an overview of the ACT-America instruments, with particular emphasis on the airborne CO2 and backscatter lidars, and the, rationale, approach, and anticipated results from this mission.

  2. Addressing inconsistencies in black carbon literature

    NASA Astrophysics Data System (ADS)

    Shonkoff, S. B.; Chafe, Z.; Smith, K. R.

    2010-12-01

    The literature describing black carbon (BC) emissions, and their effect on Earth’s climate, is growing rapidly. Unfortunately, inconsistencies in definitions; data collection and characterization; system boundaries; and time horizons have led to confusion about the relative importance of BC compared to other climate-active pollutant (CAPs). We discuss three sources of confusion: 1) Currently available BC inventories are not directly comparable to those used by the IPCC to track the greenhouse gases (GHGs) considered in the Kyoto Protocol (CO2, CH4, N2O). In particular, BC inventories often include all emissions: natural and anthropogenic in origin, controllable and non-controllable. IPCC inventories include only anthropogenic emissions. This BC accounting is appropriate for atmospheric science deliberations, but risks being interpreted as an overstatement against official Kyoto GHG inventories in a policy or control context. The IPCC convention of using 1750 as the starting year for emission inventories further complicates matters: significant BC emissions were emitted previous to that date by both human and natural sources. Though none of the pre-1750 BC emissions remain in the atmosphere today, their legacy presents challenges in assigning historical responsibility for associated global warming among sectors and regional populations. 2) Inconsistencies exist in the specific emissions sources considered in atmospheric models used to predict net BC forcing often lead to widely varying climate forcing estimates. For example, while some analyses consider only fossil fuel 1, others include both open biomass burning and fossil fuel combustion 2, and yet others include sources beyond biomass and fossil fuel burning 3. 3) Inconsistencies exist in how analyses incorporate the relationship between BC emissions and the associated cooling aerosols and processes, such as organic carbon (OC), and aerosol indirect effects (AIE). Unlike Kyoto GHGs, BC is rarely emitted in pure

  3. Comparison of carbon onions and carbon blacks as conductive additives for carbon supercapacitors in organic electrolytes

    NASA Astrophysics Data System (ADS)

    Jäckel, N.; Weingarth, D.; Zeiger, M.; Aslan, M.; Grobelsek, I.; Presser, V.

    2014-12-01

    This study investigates carbon onions (∼400 m2 g-1) as a conductive additive for supercapacitor electrodes of activated carbon and compares their performance with carbon black with high or low internal surface area. We provide a study of the electrical conductivity and electrochemical behavior between 2.5 and 20 mass% addition of each of these three additives to activated carbon. Structural characterization shows that the density of the resulting film electrodes depends on the degree of agglomeration and the amount of additive. Addition of low surface area carbon black (∼80 m2 g-1) enhances the power handling of carbon electrodes but significantly lowers the specific capacitance even when adding small amounts of carbon black. A much lower decrease in specific capacitance is observed for carbon onions and the best values are seen for carbon black with a high surface area (∼1390 m2 g-1). The overall performance benefits from the addition of any of the studied additives only at either high scan rates and/or electrolytes with high ion mobility. Normalization to the volume shows a severe decrease in volumetric capacitance and only at high current densities nearing 10 A g-1 we can see an improvement of the electrode capacitance.

  4. Characterization of Ambient Black Carbon Aerosols

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Levy, M. E.; Zheng, J.; Molina, L. T.

    2013-12-01

    Because of the strong absorption over a broad range of the electromagnetic spectra, black carbon (BC) is a key short-lived climate forcer, which contributes significantly to climate change by direct radiative forcing and is the second most important component causing global warming after carbon dioxide. The impact of BC on the radiative forcing of the Earth-Atmosphere system is highly dependent of the particle properties. In this presentation, emphasis will be placed on characterizing BC containing aerosols in at the California-Mexico border to obtain a greater understanding of the atmospheric aging and properties of ambient BC aerosols. A comprehensive set of directly measured aerosol properties, including the particle size distribution, effective density, hygroscopicity, volatility, and several optical properties, will be discussed to quantify the mixing state and composition of ambient particles. In Tijuana, Mexico, submicron aerosols are strongly influenced by vehicle emissions; subsequently, the BC concentration in Tijuana is considerably higher than most US cities with an average BC concentration of 2.71 × 2.65 g cm-3. BC accounts for 24.75 % × 9.44 of the total submicron concentration on average, but periodically accounts for over 50%. This high concentration of BC strongly influences many observed aerosol properties such as single scattering albedo, hygroscopicity, effective density, and volatility.

  5. Regional prediction of soil organic carbon content over croplands using airborne hyperspectral data

    NASA Astrophysics Data System (ADS)

    Vaudour, Emmanuelle; Gilliot, Jean-Marc; Bel, Liliane; Lefebvre, Josias; Chehdi, Kacem

    2015-04-01

    This study was carried out in the framework of the Prostock-Gessol3 and the BASC-SOCSENSIT projects, dedicated to the spatial monitoring of the effects of exogenous organic matter land application on soil organic carbon storage. It aims at identifying the potential of airborne hyperspectral AISA-Eagle data for predicting the topsoil organic carbon (SOC) content of bare cultivated soils over a large peri-urban area (221 km2) with both contrasted soils and SOC contents, located in the western region of Paris, France. Soils comprise hortic or glossic luvisols, calcaric, rendzic cambisols and colluvic cambisols. Airborne AISA-Eagle data (400-1000 nm, 126 bands) with 1 m-resolution were acquired on 17 April 2013 over 13 tracks which were georeferenced. Tracks were atmospherically corrected using a set of 22 synchronous field spectra of both bare soils, black and white targets and impervious surfaces. Atmospherically corrected track tiles were mosaicked at a 2 m-resolution resulting in a 66 Gb image. A SPOT4 satellite image was acquired the same day in the framework of the SPOT4-Take Five program of the French Space Agency (CNES) which provided it with atmospheric correction. The land use identification system layer (RPG) of 2012 was used to mask non-agricultural areas, then NDVI calculation and thresholding enabled to map agricultural fields with bare soil. All 18 sampled sites known to be bare at this very date were correctly included in this map. A total of 85 sites sampled in 2013 or in the 3 previous years were identified as bare by means of this map. Predictions were made from the mosaic spectra which were related to topsoil SOC contents by means of partial least squares regression (PLSR). Regression robustness was evaluated through a series of 1000 bootstrap data sets of calibration-validation samples. The use of the total sample including 27 sites under cloud shadows led to non-significant results. Considering 43 sites outside cloud shadows only, median

  6. Physico-chemical characterization and source tracking of black carbon at a suburban site in Beijing.

    PubMed

    Wang, Hailin; Nie, Lei; Liu, Dan; Gao, Meiping; Wang, Minyan; Hao, Zhengping

    2015-07-01

    Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC (black carbon) samples. TEM (transmission electron microscopy) results indicate that BC from combustion sources shows various patterns, and airborne BC appears spherical and about 50 nm in diameter with a homogeneous surface and turbostratic structure. The BET (Barrett-Emmett-Teller) results suggest that the surface areas of these BC particles fall in the range of 3-23 m2/g, with a total pore volume of 0.03-0.05 cm3/g and a mean pore diameter of 7-53 nm. The nitrogen adsorption-desorption isotherms are indicative of the accumulation mode and uniform pore size. O2-TPO (temperature programmed oxidation) profiles suggest that the airborne BC oxidation could be classified as the oxidation of amorphous carbon, which falls in the range of 406-490°C with peaks at 418, 423 and 475°C, respectively. Generally, the BC characteristics and source analysis suggest that airborne BC most likely comes from diesel vehicle emission at this site. PMID:26141892

  7. Black Carbon Contribution to Organic Carbon Stocks in Urban Soil.

    PubMed

    Edmondson, Jill L; Stott, Iain; Potter, Jonathan; Lopez-Capel, Elisa; Manning, David A C; Gaston, Kevin J; Leake, Jonathan R

    2015-07-21

    Soil holds 75% of the total organic carbon (TOC) stock in terrestrial ecosystems. This comprises ecosystem-derived organic carbon (OC) and black carbon (BC), a recalcitrant product of the incomplete combustion of fossil fuels and biomass. Urban topsoils are often enriched in BC from historical emissions of soot and have high TOC concentrations, but the contribution of BC to TOC throughout the urban soil profile, at a regional scale is unknown. We sampled 55 urban soil profiles across the North East of England, a region with a history of coal burning and heavy industry. Through combined elemental and thermogravimetic analyses, we found very large total soil OC stocks (31-65 kg m(-2) to 1 m), exceeding typical values reported for UK woodland soils. BC contributed 28-39% of the TOC stocks, up to 23 kg C m(-2) to 1 m, and was affected by soil texture. The proportional contribution of the BC-rich fraction to TOC increased with soil depth, and was enriched in topsoil under trees when compared to grassland. Our findings establish the importance of urban ecosystems in storing large amounts of OC in soils and that these soils also capture a large proportion of BC particulates emitted within urban areas. PMID:26114917

  8. 40 CFR 458.40 - Applicability; description of the carbon black lamp process subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... carbon black lamp process subcategory. 458.40 Section 458.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp Process Subcategory § 458.40 Applicability; description of the carbon black...

  9. 40 CFR 458.40 - Applicability; description of the carbon black lamp process subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... carbon black lamp process subcategory. 458.40 Section 458.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp Process Subcategory § 458.40 Applicability; description of the carbon black...

  10. Source attribution of black carbon in Arctic snow.

    PubMed

    Hegg, Dean A; Warren, Stephen G; Grenfell, Thomas C; Doherty, Sarah J; Larson, Timothy V; Clarke, Antony D

    2009-06-01

    Snow samples obtained at 36 sites in Alaska, Canada, Greenland, Russia, and the Arctic Ocean in early 2007 were analyzed for light-absorbing aerosol concentration together with a suite of associated chemical species. The light absorption data, interpreted as black carbon concentrations, and other chemical data were input into the EPA PMF 1.1 receptor model to explore the sources for black carbon in the snow. The analysis found four factors or sources: two distinct biomass burning sources, a pollution source, and a marine source. The first three of these were responsible for essentially all of the black carbon, with the two biomass sources (encompassing both open and closed combustion) together accounting for >90% of the black carbon. PMID:19569324

  11. Raman Spectroscopy for the Investigation of Carbon Based Black Pigments

    NASA Astrophysics Data System (ADS)

    Coccato, A.; Jehlicka, J.; Moens, L.; Vandenabeele, P.

    2014-06-01

    Carbon based black pigments play an important role among artists' materials. The disordered structure of these materials is investigated by means of Raman spectroscopy, which helps in the comprehension of their production processes.

  12. 6. VIEW SOUTHWEST, COOLING TROUGH REMAINS Imperial Carbon Black ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SOUTHWEST, COOLING TROUGH REMAINS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  13. 4. VIEW SOUTHEAST, COMPRESSOR PADS Imperial Carbon Black Plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW SOUTHEAST, COMPRESSOR PADS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  14. 7. VIEW NORTHEAST, COOLING TANK Imperial Carbon Black Plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW NORTHEAST, COOLING TANK - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  15. 3. VIEW NORTH, COOLING TANK REMAINS Imperial Carbon Black ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW NORTH, COOLING TANK REMAINS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  16. 5. VIEW SOUTH, STORAGE BUILDING PIERS Imperial Carbon Black ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW SOUTH, STORAGE BUILDING PIERS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  17. 9. VIEW EAST, STORAGE BUILDING PIERS Imperial Carbon Black ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW EAST, STORAGE BUILDING PIERS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  18. 8. VIEW NORTHEAST, WORKSHOP PIERS Imperial Carbon Black Plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW NORTHEAST, WORKSHOP PIERS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  19. 2. VIEW SOUTHWEST, COMPRESSOR PADS Imperial Carbon Black Plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW SOUTHWEST, COMPRESSOR PADS - Imperial Carbon Black Plant (Ruin), North side of North Fork of Hughes River along Bunnell Run Road just over 0.5 mile from its intersection with State Route 16, Harrisville, Ritchie County, WV

  20. Aerosol black carbon over Svalbard regions of Arctic

    NASA Astrophysics Data System (ADS)

    Gogoi, Mukunda M.; Babu, S. Suresh; Moorthy, K. Krishna; Thakur, Roseline C.; Chaubey, Jai Prakash; Nair, Vijayakumar S.

    2016-03-01

    In view of the climate impact of aerosol Black Carbon (BC) over snow covered regions (through enhanced absorption of radiation as well as snow-albedo forcing), and in view of the increasing anthropogenic presence and influence in the northern polar regions, continuous long term measurements of airborne BC have been undertaken from the Svalbard region of Norwegian Arctic (Ny-Ålesund, 79°N, 12°E, 8 m a.s.l.). This study, employing data over a period of 4-years (2010-2013) have shown a consistent spring-time enhancement in BC concentrations, having a (climatological) seasonal mean value of ∼50.3 ± 19.5 ng m-3, nearly 3-times higher than the lowest BC concentrations in summer (∼19.5 ± 6.5 ng m-3). Spectral variation of absorbance indicates that long-range transported biomass burning aerosols contribute as high as 25% to the high BC concentrations in the Arctic atmosphere in spring. Concurrent estimates of BC concentrations in the Arctic snow (for an ensemble of snow samples collected over a period of time during spring) showed values ranging from 0.6 ppb to 4.1 ppb. These values have been used to estimate the BC scavenging ratio (SR). Our studies revealed a mean value of SR ∼98 ± 46, which varied over wide range from 40 to 184 for individual samples. In a broader perspective, the seasonal variations of atmospheric BC concentrations at the Arctic are similar to those seen at the high altitude Himalayas; even though the concentrations are much lower at Arctic. It is found that synoptic conditions mainly influence the high altitude Himalayas, while the influences of local anthropogenic influences are not negligible at the Arctic in modulating the seasonal variations of absorbing aerosols.

  1. Global civil aviation black carbon emissions.

    PubMed

    Stettler, Marc E J; Boies, Adam M; Petzold, Andreas; Barrett, Steven R H

    2013-09-17

    Aircraft black carbon (BC) emissions contribute to climate forcing, but few estimates of BC emitted by aircraft at cruise exist. For the majority of aircraft engines the only BC-related measurement available is smoke number (SN)-a filter based optical method designed to measure near-ground plume visibility, not mass. While the first order approximation (FOA3) technique has been developed to estimate BC mass emissions normalized by fuel burn [EI(BC)] from SN, it is shown that it underestimates EI(BC) by >90% in 35% of directly measured cases (R(2) = -0.10). As there are no plans to measure BC emissions from all existing certified engines-which will be in service for several decades-it is necessary to estimate EI(BC) for existing aircraft on the ground and at cruise. An alternative method, called FOX, that is independent of the SN is developed to estimate BC emissions. Estimates of EI(BC) at ground level are significantly improved (R(2) = 0.68), whereas estimates at cruise are within 30% of measurements. Implementing this approach for global civil aviation estimated aircraft BC emissions are revised upward by a factor of ~3. Direct radiative forcing (RF) due to aviation BC emissions is estimated to be ~9.5 mW/m(2), equivalent to ~1/3 of the current RF due to aviation CO2 emissions. PMID:23844612

  2. Airborne radioactivity Survey of part of Saratoga NW quadrangle, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 133 square miles of Saratoga NW quadrangle, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  3. Synthesis of multiwalled carbon nanotube from different grades of carbon black using arc discharge method

    NASA Astrophysics Data System (ADS)

    Arora, Neha; Sharma, N. N.

    2016-04-01

    This paper describes the synthesis of nanotube from different grades (Tread * A(non-ASTM), N134,N121,N660 and N330)of carbon black using DC arc discharge method at 40A current for 60sec. Carbon black samples of different grades were procured from industry (Aditya Birla Science and Technology Limited, India). Scanning Electron Micrographs (SEM) of the deposited carbon nanostructures suggests that MWCNTs are formed at 40A and for a minimal exposure time of 60sec.The result formed indicates the N330 grade of carbon black gets converted to MWCNTs (Multiwall Carbon nanotube) as compared to other grades.

  4. Induction of Inflammasome-dependent Pyroptosis by Carbon Black Nanoparticles*

    PubMed Central

    Reisetter, Anna C.; Stebounova, Larissa V.; Baltrusaitis, Jonas; Powers, Linda; Gupta, Amit; Grassian, Vicki H.; Monick, Martha M.

    2011-01-01

    Inhalation of nanoparticles has been implicated in respiratory morbidity and mortality. In particular, carbon black nanoparticles are found in many different environmental exposures. Macrophages take up inhaled nanoparticles and respond via release of inflammatory mediators and in some cases cell death. Based on new data, we propose that exposure of macrophages (both a macrophage cell line and primary human alveolar macrophages) to carbon black nanoparticles induces pyroptosis, an inflammasome-dependent form of cell death. Exposure of macrophages to carbon black nanoparticles resulted in inflammasome activation as defined by cleavage of caspase 1 to its active form and downstream IL-1β release. The cell death that occurred with carbon black nanoparticle exposure was identified as pyroptosis by the protective effect of a caspase 1 inhibitor and a pyroptosis inhibitor. These data demonstrate that carbon black nanoparticle exposure activates caspase 1, increases IL-1β release after LPS priming, and induces the proinflammatory cell death, pyroptosis. The identification of pyroptosis as a cellular response to carbon nanoparticle exposure is novel and relates to environmental and health impacts of carbon-based particulates. PMID:21525001

  5. Black Smoke and Black Carbon: Further investigation of the relationship between these ambient air metrics

    NASA Astrophysics Data System (ADS)

    Quincey, Paul; Butterfield, David; Green, David; Fuller, Gary W.

    2011-07-01

    A previous paper ( Quincey, 2007) described a simple quadratic relationship between OECD Black Smoke Index ( IBS) and Black Carbon (aethalometry) measurements of ambient particulate samples ( CBC): C=√{4.18I+59.6}-7.72, based on their common link to optical absorption coefficient, supported by a single dataset. Further parallel datasets are presented here that support the general validity of the relationship, while highlighting limitations to the traditional Black Smoke method at kerbside sites, and variations between sites. The opportunity is taken to clarify some confusing aspects concerning published standard methods for Black Smoke.

  6. Measurements of Black Carbon and aerosol absorption during global circumnavigation and Arctic campaigns

    NASA Astrophysics Data System (ADS)

    Močnik, Griša; Drinovec, Luka; Vidmar, Primož; Lenarčič, Matevž

    2015-04-01

    . Lenarčič, Airborne measurements of Black Carbon during the GLW Flight using miniature high-performance Aethalometers, http://www.worldgreenflight.com/ 3. Samset et al., Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations, Atmos. Chem. Phys. Discuss., 14, 20083-20115, doi:10.5194/acpd-14-20083-2014, 2014. 4. Bond et al., Bounding the role of black carbon in the climate system: a scientific assessment, J. Geophys. Res. Atmos., 10 118, 5380-5552, doi:10.1002/jgrd.50171, 2013.

  7. The atmospheric lifetime of black carbon

    NASA Astrophysics Data System (ADS)

    Cape, J. N.; Coyle, M.; Dumitrean, P.

    2012-11-01

    Black carbon (BC) in the atmosphere contributes to the human health effects of particulate matter and contributes to radiative forcing of climate. The lifetime of BC, particularly the smaller particle sizes (PM2.5) which can be transported over long distances, is therefore an important factor in determining the range of such effects, and the spatial footprint of emission controls. Theory and models suggest that the typical lifetime of BC is around one week. The frequency distributions of measurements of a range of hydrocarbons at a remote rural site in southern Scotland (Auchencorth Moss) between 2007 and 2010 have been used to quantify the relationship between atmospheric lifetime and the geometric standard deviation of observed concentration. The analysis relies on an assumed common major emission source for hydrocarbons and BC, namely diesel-engined vehicles. The logarithm of the standard deviation of the log-transformed concentration data is linearly related to hydrocarbon lifetime, and the same statistic for BC can be used to assess the lifetime of BC relative to the hydrocarbons. Annual average data show BC lifetimes in the range 4-12 days, for an assumed OH concentration of 7 × 105 cm-3. At this site there is little difference in BC lifetime between winter and summer, despite a 3-fold difference in relative hydrocarbon lifetimes. This observation confirms the role of wet deposition as an important removal process for BC, as there is no difference in precipitation between winter and summer at this site. BC lifetime was significantly greater in 2010, which had 23% less rainfall than the preceding 3 years.

  8. Australian climate-carbon cycle feedback reduced by soil black carbon

    NASA Astrophysics Data System (ADS)

    Lehmann, Johannes; Skjemstad, Jan; Sohi, Saran; Carter, John; Barson, Michele; Falloon, Pete; Coleman, Kevin; Woodbury, Peter; Krull, Evelyn

    2008-12-01

    Annual emissions of carbon dioxide from soil organic carbon are an order of magnitude greater than all anthropogenic carbon dioxide emissions taken together. Global warming is likely to increase the decomposition of soil organic carbon, and thus the release of carbon dioxide from soils, creating a positive feedback. Current models of global climate change that recognize this soil carbon feedback are inaccurate if a larger fraction of soil organic carbon than postulated has a very slow decomposition rate. Here we show that by including realistic stocks of black carbon in prediction models, carbon dioxide emissions are reduced by 18.3 and 24.4% in two Australian savannah regions in response to a warming of 3∘C over 100 years. This reduction in temperature sensitivity, and thus the magnitude of the positive feedback, results from the long mean residence time of black carbon, which we estimate to be approximately 1,300 and 2,600 years, respectively. The inclusion of black carbon in climate models is likely to require spatially explicit information about its distribution, given that the black carbon content of soils ranged from 0 to 82% of soil organic carbon in a continental-scale analysis of Australia. We conclude that accurate information about the distribution of black carbon in soils is important for projections of future climate change.

  9. Black Carbon in Estuarine and Coastal Ocean Dissolved Organic Matter

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Analysis of high-molecular-weight dissolved organic matter (DOM) from two estuaries in the northwest Atlantic Ocean reveals that black carbon (BC) is a significant component of previously uncharacterized DOM, suggesting that river-estuary systems are important exporters of recalcitrant dissolved organic carbon to the ocean.

  10. Enviro-HIRLAM Applicability for Black Carbon Studies in Arctic

    NASA Astrophysics Data System (ADS)

    Nuterman, Roman; Mahura, Alexander; Baklanov, Alexander; Kurganskiy, Alexander; Amstrup, Bjarne; Kaas, Eigil

    2015-04-01

    One of the main aims of the Nordic CarboNord project ("Impact of black carbon on air quality and climate in Northern Europe and Arctic") is focused on providing new information on distribution and effects of black carbon in Northern Europe and Arctic. It can be done through assessing robustness of model predictions of long-range black carbon distribution and its relation to climate change and forcing. In our study, the online integrated meteorology-chemistry/aerosols model - Enviro-HIRLAM (Environment - HIgh Resolution Limited Area Model) - is used. This study, at first, is focused on adaptation (model setup, domain for the Northern Hemisphere and Arctic region, emissions, boundary conditions, refining aerosols microphysics and chemistry, cloud-aerosol interaction processes) of Enviro-HIRLAM model and selection of most unfavorable weather and air pollution episodes for the Arctic region. Simulations of interactions between black carbon and meteorological processes in northern conditions for selected episodes will be performed (at DMI's supercomputer HPC CRAY-XT5), and then long-term simulations at regional scale for selected winter vs. summer months. Modelling results will be compared on a diurnal cycle and monthly basis against observations for key meteorological parameters (such as air temperature, wind speed, relative humidity, and precipitation) as well as aerosol concentration. Finally, evaluation of black carbon atmospheric transport, dispersion, and deposition patterns at different spatio-temporal scales; physical-chemical processes and transformations of black carbon containing aerosols; and interactions and effects between black carbon and meteorological processes in Arctic weather conditions will be done.

  11. Relationships between MODIS black-sky shortwave albedo and airborne lidar based forest canopy structure

    NASA Astrophysics Data System (ADS)

    Korhonen, Lauri; Rautiainen, Miina; Arumäe, Tauri; Lang, Mait; Flewelling, James; Tokola, Timo; Stenberg, Pauline

    2016-04-01

    Albedo is one of the essential climate variables affecting the Earth's radiation balance. It is however not well understood how changes in forest canopy structure influence the albedo. Canopy structure can be mapped consistently for fairly large areas using airborne lidar sensors. Our objective was to study the relationships between MODIS shortwave black sky albedo product and lidar-based estimates of canopy structure in different biomes ranging from arctic to tropical. Our study is based on six structurally different forest sites located in Finland, Estonia, USA and Laos. Lidar-based mean height of the canopy, canopy cover and their transformations were used as predictor variables to describe the canopy structure. Tree species composition was also included for the three sites where it was available. We noticed that the variables predicting albedo best were different in open and closed canopy forests. In closed canopy forests, the species information was more important than canopy structure variables (R2=0.31-0.32) and using only structural variables resulted in poor R2 (0.13-0.15). If the 500 m MODIS pixel contained a mixture of forests and other land cover types, the albedo was strongly related to the forest area percent. In open canopy forests, structural variables such as canopy cover or height explained albedo well, but species information still improved the models (R2=0.27-0.52). We obtained the highest R2=0.52 using only structural variables in Laos on a partially degraded tropical forest with large variation in canopy cover. The different canopy structure variables were often correlated and the one that provided the best model changed from site to site.

  12. Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

    NASA Astrophysics Data System (ADS)

    Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.; Storey, John M.; Romanov, Alexander; Hodson, Elke L.; Cresko, Joe; Morozova, Irina; Ignatieva, Yulia; Cabaniss, John

    2015-11-01

    Development of reliable source emission inventories is particularly needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This study develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile. Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30-65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow

  13. Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

    DOE PAGESBeta

    Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.; Storey, John M.; Romanov, Alexander; Hodson, Elke L.; Cresko, Joe; Morozova, Irina; Ignatieva, Yulia; Cabaniss, John

    2015-10-02

    Development of reliable source emission inventories is needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This paper develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile.more » Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30–65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert

  14. Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

    SciTech Connect

    Huang, Kan; Fu, Joshua S.; Prikhodko, Vitaly Y.; Storey, John M.; Romanov, Alexander; Hodson, Elke L.; Cresko, Joe; Ignatieva, Yulia; Cabaniss, John

    2015-10-02

    Development of reliable source emission inventories is needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This paper develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile. Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30–65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert, and

  15. Formation mechanism of diamond nanocrystal from catalysed carbon black

    NASA Astrophysics Data System (ADS)

    Wen, Bin; Li, Tingju; Dong, Chuang; Zhang, Xingguo; Yao, Shan; Cao, Zhiqiang; Wang, Dehe; Ji, Shouhua; Jin, Junze

    2004-10-01

    Recently, our group has synthesized nanocrystal n-diamond and diamond-like carbon (DLC) from catalysed carbon black. Based on the results of XRD, TGA and DTA, a formation mechanism has been proposed to explain the phase transformation from carbon black to diamond nanocrystal. With the increase of temperature and hence the carbon diffusion in iron, the phase sequence is from Fe(OH)3 into Fe2O3, agr-Fe, ggr-Fe, then liquid iron. When the carbon in the liquid iron is saturated, DLC or graphite separates out of the liquid iron. With decrease of temperature, the carbon in ggr-Fe is separated out, and n-diamond nuclei form and grow.

  16. Black carbon and organic matter stabilization in soil

    NASA Astrophysics Data System (ADS)

    Lehmann, J.; Liang, B.; Sohi, S.; Gaunt, J.

    2007-12-01

    Interaction with minerals is key to stabilization of organic matter in soils. Stabilization is commonly perceived to occur due to entrapment in pore spaces, encapsulation within aggregates or interaction with mineral surfaces. Typically only interactions between organic matter and minerals are considered in such a model. Here we demonstrate that black carbon may act very similar to minerals in soil in that it enhances the stabilization of organic matter. Mineralization of added organic matter was slower and incorporation into intra-aggregate fractions more rapid in the presence of black carbon. Added double-labeled organic matter was recovered in fractions with high amounts of black carbon. Synchrotron-based near-edge x-ray fine structure (NEXAFS) spectroscopy coupled to scanning transmission x-ray microscopy (STXM) suggested a possible interaction of microorganisms with black carbon surfaces and metabolization of residues. These findings suggest a conceptual model that includes carbon-carbon interactions and by-passing for more rapid stabilization of litter into what is commonly interpreted as stable carbon pools.

  17. Can reducing black carbon emissions counteract global warming?

    SciTech Connect

    Tami C. Bond; Haolin Sun

    2005-08-15

    Field measurements and model results have recently shown that aerosols may have important climatic impacts. One line of inquiry has investigated whether reducing climate-warming soot or black carbon aerosol emissions can form a viable component of mitigating global warming. Black carbon is produced by poor combustion, from our example hard coal cooking fires for and industrial pulverized coal boilers. The authors review and acknowledge scientific arguments against considering aerosols and greenhouse gases in a common framework, including the differences in the physical mechanisms of climate change and relevant time scales. It is argued that such a joint consideration is consistent with the language of the United Nations Framework Convention on Climate Change. Results from published climate-modeling studies are synthesized to obtain a global warming potential for black carbon relative to that of CO{sub 2} (680 on a 100 year basis). This calculation enables a discussion of cost-effectiveness for mitigating the largest sources of black carbon. It is found that many emission reductions are either expensive or difficult to enact when compared with greenhouse gases, particularly in Annex I countries. Finally, a role for black carbon in climate mitigation strategies is proposed that is consistent with the apparently conflicting arguments raised during the discussion. Addressing these emissions is a promising way to reduce climatic interference primarily for nations that have not yet agreed to address greenhouse gas emissions and provides the potential for a parallel climate agreement. 31 refs., 3 figs., 1 tab.

  18. Black carbon particles in the urban atmosphere in Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Gengchen; Bai, Jianhui; Kong, Qinxin; Emilenko, Alexander

    2005-09-01

    A study of the concentration of black carbon particles and its variation in the urban atmosphere has been carried out since 1996 in the Beijing area. The measurements were done in the late autumn and early winter each year, the period before and after domestic heating activities begin. The results show the presence of black carbon particles at the high level that vary over a large range in the urban atmosphere in Beijing. The mean value of daily average concentration for the whole observation period of 1996 2004 is 20.0 μg m-3. An evident decrease of black carbon particle concentration in the Beijing area is observed after 2000, and the daily average concentration of black carbon particles is estimated to be 16.0 μg m-3 with a variation range of 2.10 50.50 μg m-3 for the period of 2000 2004. The observation method and main variation behavior characteristics of black carbon particles in the urban atmosphere in the Beijing area are given and discussed.

  19. Low-wind and other microclimatic factors in near-road black carbon variability: A case study and assessment implications

    PubMed Central

    Liang, Marissa S.; Keener, Timothy C.; Birch, M. Eileen; Baldauf, Richard; Neal, Jill; Yang, Y. Jeffrey

    2015-01-01

    Airborne black carbon from urban traffic is a climate forcing agent and has been associated with health risks to near-road populations. In this paper, we describe a case study of black carbon concentration and compositional variability at and near a traffic-laden multi-lane highway in Cincinnati, Ohio, using an onsite aethalometer and filter-based NIOSH Method 5040 measurements; the former measured 1-min average black carbon concentrations and the latter determined the levels of organic and elemental carbon (OC and EC) averaged over an approximately 2-h time interval. The results show significant wind and temperature effects on black carbon concentration and composition in a way more complex than predicted by Gaussian dispersion models. Under oblique low winds, namely ux[= u × sin(g=q)]~ (0,−0.5 m s−1), which mostly occurred during morning hours, black carbon concentrations per unit traffic flow were highest and had large variation. The variability did not always follow Gaussian dispersion but was characteristic of a uniform distribution at a near-road distance. Under all other wind conditions, the near-road black carbon variation met Gaussian dispersion characteristics. Significant differences in roadside dispersion are observed between OC and EC fractions, between PM2.5 and PM10–2.5, and between the morning period and rest of the day. In a general case, the overall black carbon variability at the multi-lane highway can be stated as bimodal consisting of Gaussian dispersion and non-Gaussian uniform distribution. Transition between the two types depends on wind velocity and wind angle to the traffic flow. In the order of decreasing importance, the microclimatic controlling factors over the black carbon variability are: 1) wind velocity and the angle with traffic; 2) diurnal temperature variations due to thermal buoyancy; and 3) downwind Gaussian dispersion. Combinations of these factors may have created various traffic–microclimate interactions that have

  20. 40 CFR 458.30 - Applicability; description of the carbon black channel process subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... carbon black channel process subcategory. 458.30 Section 458.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel Process Subcategory § 458.30 Applicability; description of the carbon...

  1. 40 CFR 458.20 - Applicability: description of the carbon black thermal process subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... carbon black thermal process subcategory. 458.20 Section 458.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal Process Subcategory § 458.20 Applicability: description of the carbon...

  2. 40 CFR 458.10 - Applicability; description of the carbon black furnace process subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... carbon black furnace process subcategory. 458.10 Section 458.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Furnace Process Subcategory § 458.10 Applicability; description of the carbon...

  3. 40 CFR 458.30 - Applicability; description of the carbon black channel process subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... carbon black channel process subcategory. 458.30 Section 458.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel Process Subcategory § 458.30 Applicability; description of the carbon...

  4. 40 CFR 458.20 - Applicability: description of the carbon black thermal process subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... carbon black thermal process subcategory. 458.20 Section 458.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal Process Subcategory § 458.20 Applicability: description of the carbon...

  5. 40 CFR 458.10 - Applicability; description of the carbon black furnace process subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... carbon black furnace process subcategory. 458.10 Section 458.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Furnace Process Subcategory § 458.10 Applicability; description of the carbon...

  6. Dye sensitized solar cells with carbon black as counter electrodes

    NASA Astrophysics Data System (ADS)

    Lin, Chi-Feng; Chou, Yu-Chen; Haung, Jhang-Fu; Chen, Pin-Hung; Han, Hsieh-Cheng; Chiu, Kuo-Yuan; Su, Yuhlong Oliver

    2016-03-01

    In this experiment, we use carbon black as counter electrodes to replace the conventional platinum electrodes in dye sensitized solar cell (DSSC). The electrical properties and device efficiency with carbon black counter electrodes with various concentrations, and under the annealing temperature from 100 to 500 °C are discussed. After the proper annealing process, the conductivity and redoxing ability of the carbon black is improved, resulted in the enhancement of the electrical characteristics, especially fill factor, of the device. The highest device efficiency was 7.28% with the JSC of 14.70 mA/cm2, VOC of 0.75 V, and fill factor of 0.67 under 1-sun AM 1.5G solar illumination.

  7. Airborne radioactivity surveys of parts of Savery SW and Savery SE quadrangles, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 222 square miles of Savery SW and Savery SE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  8. Airborne radioactivity survey of parts of Savery NW and Savery NE quadrangles, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 266 square miles of Savery NW and Savery NE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  9. Black carbon over the Amazon during SAMBBA: it gets everywhere

    NASA Astrophysics Data System (ADS)

    Morgan, W.; Allan, J. D.; Flynn, M.; Darbyshire, E.; Liu, D.; Szpek, K.; Langridge, J.; Johnson, B. T.; Haywood, J.; Longo, K.; Artaxo, P.; Coe, H.

    2014-12-01

    Biomass burning represents a major source of Black Carbon (BC) aerosol to the atmosphere, which can result in major perturbations to weather, climate and ecosystem development. Large uncertainties in these impacts prevail, particularly on regional scales. One such region is the Amazon Basin, where large, intense and frequent burning occurs on an annual basis during the dry season. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to BC aerosol properties. Results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by a DMT Single Particle Soot Photometer (SP2) and an Aerodyne Aerosol Mass Spectrometer (AMS). The physical, chemical and optical properties of BC-containing particles across the region will be characterised, with particular emphasis on the vertical distribution. BC was ubiquitous across the region, with measurements extending from heavily deforested regions in the Western Amazon Basin, through to agricultural fires in the Cerrado (Savannah-like) region and more pristine areas over the Amazon Rainforest. Measurements in the vicinity of Manaus (a city located deep into the jungle) were also conducted. BC concentrations peaked within the boundary layer at a height of around 1.5km. BC-containing particles were found to be rapidly coated in the near-field, with little evidence for additional coating upon advection and dilution. Biomass burning layers within the free troposphere were routinely observed. BC-containing particles within such layers were typically associated with less coating than those within the boundary layer, suggestive of wet removal of more coated BC particles. The importance of such properties in relation to the

  10. A Novel Airborne Carbon Isotope Analyzer for Methane and Carbon Dioxide Source Fingerprinting

    NASA Astrophysics Data System (ADS)

    Berman, E. S.; Huang, Y. W.; Owano, T. G.; Leifer, I.

    2014-12-01

    Recent field studies on major sources of the important greenhouse gas methane (CH4) indicate significant underestimation of methane release from fossil fuel industrial (FFI) and animal husbandry sources, among others. In addition, uncertainties still exist with respect to carbon dioxide (CO2) measurements, especially source fingerprinting. CO2 isotopic analysis provides a valuable in situ measurement approach to fingerprint CH4 and CO2as associated with combustion sources, leakage from geologic reservoirs, or biogenic sources. As a result, these measurements can characterize strong combustion source plumes, such as power plant emissions, and discriminate these emissions from other sources. As part of the COMEX (CO2 and MEthane eXperiment) campaign, a novel CO2 isotopic analyzer was installed and collected data aboard the CIRPAS Twin Otter aircraft. Developing methods to derive CH4 and CO2 budgets from remote sensing data is the goal of the summer 2014 COMEX campaign, which combines hyperspectral imaging (HSI) and non-imaging spectroscopy (NIS) with in situ airborne and surface data. COMEX leverages the synergy between high spatial resolution HSI and moderate spatial resolution NIS. The carbon dioxide isotope analyzer developed by Los Gatos Research (LGR) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology and incorporates proprietary internal thermal control for high sensitivity and optimal instrument stability. This analyzer measures CO2 concentration as well as δ13C, δ18O, and δ17O from CO2 at natural abundance (100-3000 ppm). The laboratory accuracy is ±1.2 ppm (1σ) in CO2 from 370-1000 ppm, with a long-term (1000 s) precision of ±0.012 ppm. The long-term precision for both δ13C and δ18O is 0.04 ‰, and for δ17O is 0.06 ‰. The analyzer was field-tested as part of the COWGAS campaign, a pre-cursor campaign to COMEX in March 2014, where it successfully discriminated plumes related to combustion processes associated with

  11. Double-Pulse Two-Micron IPDA Lidar Simulation for Airborne Carbon Dioxide Measurements

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta

    2015-01-01

    An advanced double-pulsed 2-micron integrated path differential absorption lidar has been developed at NASA Langley Research Center for measuring atmospheric carbon dioxide. The instrument utilizes a state-of-the-art 2-micron laser transmitter with tunable on-line wavelength and advanced receiver. Instrument modeling and airborne simulations are presented in this paper. Focusing on random errors, results demonstrate instrument capabilities of performing precise carbon dioxide differential optical depth measurement with less than 3% random error for single-shot operation from up to 11 km altitude. This study is useful for defining CO2 measurement weighting, instrument setting, validation and sensitivity trade-offs.

  12. Comparison between carbon monoxide measurements from spaceborne and airborne platforms

    NASA Technical Reports Server (NTRS)

    Connors, V. S.; Cahoon, D. R.; Reichle, H. G., Jr.; Scheel, H. E.

    1991-01-01

    The measurements of air pollution from satellites (MAPS) experiment measured the distribution of middle tropospheric carbon monoxide (CO) from the Space Shuttle during October 1984. A critical area of the experiment is the assessment of experimental error of the MAPS data. This error is determined by the comparison between the space-based CO data and concurrent, direct CO measurements taken aboard aircraft. Because of the variability in the CO measurements near land sources, a strategy for comparing the tropospheric CO measurements over the remote oceans is presented.

  13. Flux Of Carbon from an Airborne Laboratory (FOCAL): Synergy of airborne and surface measures of carbon emission and isotopologue content from tundra landscape in Alaska

    NASA Astrophysics Data System (ADS)

    Dobosy, R.; Dumas, E.; Sayres, D. S.; Kochendorfer, J.

    2013-12-01

    Arctic tundra, recognized as a potential major source of new atmospheric carbon, is characterized by low topographic relief and small-scale heterogeneity consisting of small lakes and intervening tundra vegetation. This fits well the flux-fragment method (FFM) of analysis of data from low-flying aircraft. The FFM draws on 1)airborne eddy-covariance flux measurements, 2)a classified surface-characteristics map (e.g. open water vs tundra), 3)a footprint model, and 4)companion surface-based eddy-covariance flux measurements. The FOCAL, a collaboration among Harvard University's Anderson Group, NOAA's Atmospheric Turbulence and Diffusion Division (ATDD), and Aurora Flight Sciences, Inc., made coordinated flights in 2013 August with a collaborating surface site. The FOCAL gathers not only flux data for CH4 and CO2 but also the corresponding carbon-isotopologue content of these gases. The surface site provides a continuous sample of carbon flux from interstitial tundra over time throughout the period of the campaign. The FFM draws samples from the aircraft data over many instances of tundra and also open water. From this we will determine how representative the surface site is of the larger area (100 km linear scale), and how much the open water differs from the tundra as a source of carbon.

  14. A universal airborne LiDAR approach for tropical forest carbon mapping.

    PubMed

    Asner, Gregory P; Mascaro, Joseph; Muller-Landau, Helene C; Vieilledent, Ghislain; Vaudry, Romuald; Rasamoelina, Maminiaina; Hall, Jefferson S; van Breugel, Michiel

    2012-04-01

    Airborne light detection and ranging (LiDAR) is fast turning the corner from demonstration technology to a key tool for assessing carbon stocks in tropical forests. With its ability to penetrate tropical forest canopies and detect three-dimensional forest structure, LiDAR may prove to be a major component of international strategies to measure and account for carbon emissions from and uptake by tropical forests. To date, however, basic ecological information such as height-diameter allometry and stand-level wood density have not been mechanistically incorporated into methods for mapping forest carbon at regional and global scales. A better incorporation of these structural patterns in forests may reduce the considerable time needed to calibrate airborne data with ground-based forest inventory plots, which presently necessitate exhaustive measurements of tree diameters and heights, as well as tree identifications for wood density estimation. Here, we develop a new approach that can facilitate rapid LiDAR calibration with minimal field data. Throughout four tropical regions (Panama, Peru, Madagascar, and Hawaii), we were able to predict aboveground carbon density estimated in field inventory plots using a single universal LiDAR model (r ( 2 ) = 0.80, RMSE = 27.6 Mg C ha(-1)). This model is comparable in predictive power to locally calibrated models, but relies on limited inputs of basal area and wood density information for a given region, rather than on traditional plot inventories. With this approach, we propose to radically decrease the time required to calibrate airborne LiDAR data and thus increase the output of high-resolution carbon maps, supporting tropical forest conservation and climate mitigation policy. PMID:22033763

  15. Green Carbon, Black Carbon, White Carbon: Simultaneous Differentiation Between Soil Organic Matter, Pyrogenic Carbon and Carbonates Using Thermal Analysis Techniques

    NASA Astrophysics Data System (ADS)

    Plante, A. F.; Peltre, C.; Chan, J.; Baumgartl, T.; Erskine, P.; Apesteguía, M.; Virto, I.

    2014-12-01

    Quantification of soil carbon stocks and fluxes continues to be an important endeavor in assessments of soil quality, and more broadly in assessments of ecosystem functioning. The quantification of soil carbon in alkaline, carbonate-containing soils, such as those found in Mediterranean areas, is complicated by the need to differentiate between organic carbon (OC) and inorganic carbon (IC), which continues to present methodological challenges. Acidification is frequently used to eliminate carbonates prior to soil OC quantification, but when performed in the liquid phase, can promote the dissolution and loss of a portion of the OC. Acid fumigation (AF) is increasingly preferred for carbonate removal, but its effectiveness is difficult to assess using conventional elemental and isotopic analyses. The two-step approach is time, labor and cost intensive, and generates additional uncertainties from the calculations. Quantification of the actively cycling pool of soil organic C (SOC) in many soils is further complicated by the potential presence of more recalcitrant/stable forms such as pyrogenic or black carbon (BC) derived from incomplete combustion of vegetation, or even geogenic carbon such as coal. The wide spectrum of materials currently considered BC makes its quantification challenging. The chemical method using benzene polycarboxylic acids (BPCAs) as markers of condensed aromatic structures indicative of pyrogenic C is highly time, labor and cost intensive, and can generate artifacts. Several research groups are now developing method for the simultaneous identification and quantification of these various forms of soil carbon using thermal analysis techniques such as thermogravimetry, differential scanning calorimetry and evolved gas analysis. The objective of this presentation is to provide a general overview and specific examples of the current progress and technical challenges in this evolving methodology.

  16. Occupational exposure to carbon black: a particulate sampling study.

    PubMed

    Smith, R G; Musch, D C

    1982-12-01

    In order to determine the particulate exposure levels within carbon black production plants, a sampling survey involving workers from seven carbon black producers was initiated in late 1979. A total of 1,951 acceptable samples (1,564 total dust and 387 respirable dust) were collected from closed-face filter cassettes worn by carbon black workers performing normal work operations. A one-centimeter cyclone separator was employed for respirable dust sampling. Overall sampling distributions of the time-weighted average values generated from the survey were best described by the log-normal distribution. Characterization of the particulate exposures to workers is provided for the various areas of employment and specific jobs within these areas. Summary geometric mean time-weighted average values by area of employment and by job category are well within the carbon black permissible exposure limit (PEL) of 3.5 mg/m3. Identification of those job categories subject to relatively higher particulate exposures, and quantification of these exposures, is essential to the effective industrial hygiene monitoring and control of worker exposures. PMID:7158607

  17. Overview of EPA activities and research related to black carbon

    EPA Science Inventory

    The purpose of this international presentation is to give an overview of EPA activities related to black carbon (BC). This overview includes some summary information on how EPA defines BC, current knowledge on United States emissions and forecasted emission reductions, and ongoin...

  18. Black carbon emissions reductions from combustion of alternative jet fuels

    NASA Astrophysics Data System (ADS)

    Speth, Raymond L.; Rojo, Carolina; Malina, Robert; Barrett, Steven R. H.

    2015-03-01

    Recent measurement campaigns for alternative aviation fuels indicate that black carbon emissions from gas turbines are reduced significantly with the use of alternative jet fuels that are low in aromatic content. This could have significant climate and air quality-related benefits that are currently not accounted for in environmental assessments of alternative jet fuels. There is currently no predictive way of estimating aircraft black carbon emissions given an alternative jet fuel. We examine the results from available measurement campaigns and propose a first analytical approximation (termed 'ASAF') of the black carbon emissions reduction associated with the use of paraffinic alternative jet fuels. We establish a relationship between the reduction in black carbon emissions relative to conventional jet fuel for a given aircraft, thrust setting relative to maximum rated thrust, and the aromatic volume fraction of the (blended) alternative fuel. The proposed relationship is constrained to produce physically meaningful results, makes use of only one free parameter and is found to explain a majority of the variability in measurements across the engines and fuels that have been tested.

  19. Carbon dioxide gasification of carbon black: isotope study of carbonate catalysis

    SciTech Connect

    Saber, J.M.; Falconer, J.L.; Brown, L.F.

    1984-11-01

    Temperature-programmed reaction was used with labeled isotopes (/sup 13/C and /sup 18/O) to study interactions between carbon black and potassium carbonate in pure He and 10% CO/sub 2//90% He atmospheres. Catalytic gasification precursor complexes were observed. Carbon and oxygen-bearing carbon surface groups interacted with the carbonate above 500 K to form surface complexes. Between 500 and 950 K, and in the presence of gaseous CO/sub 2/, the complexes participated in C and O exchange with the gas phase while oxygen atoms within the complexes also exchanged with those on the carbon surface. As the temperature rose, the complexes decomposed, with CO/sub 2/ the initial product. Decomposition started around 500 K in pure He, and around 950 K in CO/sub 2//He. Catalytic gasification began only after decomposition of significant portions of the complexes. Elemental potassium formed, and the active catalyst appears to alternate between being potassium metal and a potassium-oxygen-carbon complex. Potassium carbonate is not part of the catalytic cycle. 20 references, 10 figures.

  20. Snow darkening caused by black carbon emitted from fires

    NASA Astrophysics Data System (ADS)

    Engels, Jessica; Kloster, Silvia; Bourgeois, Quentin

    2014-05-01

    We implemented the effect of snow darkening caused by black carbon (BC) emitted from forest fires into the Max Planck Institute for Meteorology Earth System Model (MPI-M ESM) to estimate its potential climate impact of present day fire occurrence. Considerable amounts of black carbon emitted from fires are transported into snow covered regions. Already very small quantities of black carbon reduce the snow reflectance, with consequences for snow melting and snow spatial coverage. Therefore, the SNICAR (SNow And Ice Radiation) model (Flanner and Zender (2005)) is implemented in the land surface component (JSBACH) of the atmospheric general circulation model ECHAM6, developed at the MPI-M. The SNICAR model includes amongst other processes a complex calculation of the snow albedo depending on black carbon in snow and snow grain growth depending on water vapor fluxes for a five layer snow scheme. For the implementation of the SNICAR model into the one layer scheme of ECHAM6-JSBACH, we used the SNICAR-online version (http://snow.engin.umich.edu). This single-layer simulator provides the albedo of snow for selectable combinations of impurity content (e.g. black carbon), snow grain size, and incident solar flux characteristics. From this scheme we derived snow albedo values for black carbon in snow concentrations ranging between 0 and 1500 ng(BC)/g(snow) and for different snow grain sizes for the visible (0.3 - 0.7 µm) and near infrared range (0.7 - 1.5 µm). As snow grains grow over time, we assign different snow ages to different snow grain sizes (50, 150, 500, and 1000 µm). Here, a radius of 50 µm corresponds to new snow, whereas a radius of 1000 µm corresponds to old snow. The required snow age is taken from the BATS (Biosphere Atmosphere Transfer Scheme, Dickinson et al. (1986)) snow albedo implementation in ECHAM6-JSBACH. Here, we will present an extended evaluation of the model including a comparison of modeled black carbon in snow concentrations to observed

  1. 40 CFR 458.20 - Applicability: description of the carbon black thermal process subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... carbon black thermal process subcategory. 458.20 Section 458.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal Process Subcategory § 458.20 Applicability: description of...

  2. 40 CFR 458.30 - Applicability; description of the carbon black channel process subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... carbon black channel process subcategory. 458.30 Section 458.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel Process Subcategory § 458.30 Applicability; description of...

  3. 40 CFR 458.40 - Applicability; description of the carbon black lamp process subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... carbon black lamp process subcategory. 458.40 Section 458.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp Process Subcategory § 458.40 Applicability; description of the...

  4. 40 CFR 458.30 - Applicability; description of the carbon black channel process subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... carbon black channel process subcategory. 458.30 Section 458.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel Process Subcategory § 458.30 Applicability; description of...

  5. 40 CFR 458.40 - Applicability; description of the carbon black lamp process subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... carbon black lamp process subcategory. 458.40 Section 458.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp Process Subcategory § 458.40 Applicability; description of the...

  6. 40 CFR 458.30 - Applicability; description of the carbon black channel process subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... carbon black channel process subcategory. 458.30 Section 458.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel Process Subcategory § 458.30 Applicability; description of...

  7. 40 CFR 458.20 - Applicability: description of the carbon black thermal process subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... carbon black thermal process subcategory. 458.20 Section 458.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal Process Subcategory § 458.20 Applicability: description of...

  8. 40 CFR 458.40 - Applicability; description of the carbon black lamp process subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... carbon black lamp process subcategory. 458.40 Section 458.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp Process Subcategory § 458.40 Applicability; description of the...

  9. 40 CFR 458.20 - Applicability: description of the carbon black thermal process subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... carbon black thermal process subcategory. 458.20 Section 458.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal Process Subcategory § 458.20 Applicability: description of...

  10. 40 CFR 458.10 - Applicability; description of the carbon black furnace process subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... carbon black furnace process subcategory. 458.10 Section 458.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Carbon Black Furnace Process Subcategory § 458.10 Applicability; description of the carbon black furnace process subcategory. The provisions of this subpart are applicable to...

  11. 40 CFR 458.10 - Applicability; description of the carbon black furnace process subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... carbon black furnace process subcategory. 458.10 Section 458.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Carbon Black Furnace Process Subcategory § 458.10 Applicability; description of the carbon black furnace process subcategory. The provisions of this subpart are applicable to...

  12. 40 CFR 458.10 - Applicability; description of the carbon black furnace process subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... carbon black furnace process subcategory. 458.10 Section 458.10 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Carbon Black Furnace Process Subcategory § 458.10 Applicability; description of the carbon black furnace process subcategory. The provisions of this subpart are applicable to...

  13. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Carbon black, (4-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10150 Carbon black, (4-methylphenyl)-modified... substance identified generically as carbon black, (4-methylphenyl)-modified, substituted (PMN P-07-523)...

  14. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Carbon black, (4-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10150 Carbon black, (4-methylphenyl)-modified... substance identified generically as carbon black, (4-methylphenyl)-modified, substituted (PMN P-07-523)...

  15. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Carbon black, (3-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10149 Carbon black, (3-methylphenyl)-modified... substance identified generically as carbon black, (3-methylphenyl)-modified, substituted (PMN P-07-522)...

  16. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Carbon black, (4-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10150 Carbon black, (4-methylphenyl)-modified... substance identified generically as carbon black, (4-methylphenyl)-modified, substituted (PMN P-07-523)...

  17. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Carbon black, (3-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10149 Carbon black, (3-methylphenyl)-modified... substance identified generically as carbon black, (3-methylphenyl)-modified, substituted (PMN P-07-522)...

  18. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carbon black, (4-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10150 Carbon black, (4-methylphenyl)-modified... substance identified generically as carbon black, (4-methylphenyl)-modified, substituted (PMN P-07-523)...

  19. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Carbon black, (3-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10149 Carbon black, (3-methylphenyl)-modified... substance identified generically as carbon black, (3-methylphenyl)-modified, substituted (PMN P-07-522)...

  20. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carbon black, (3-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10149 Carbon black, (3-methylphenyl)-modified... substance identified generically as carbon black, (3-methylphenyl)-modified, substituted (PMN P-07-522)...

  1. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Carbon black, (4-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10150 Carbon black, (4-methylphenyl)-modified... substance identified generically as carbon black, (4-methylphenyl)-modified, substituted (PMN P-07-523)...

  2. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Carbon black, (3-methylphenyl... Significant New Uses for Specific Chemical Substances § 721.10149 Carbon black, (3-methylphenyl)-modified... substance identified generically as carbon black, (3-methylphenyl)-modified, substituted (PMN P-07-522)...

  3. Aqueous carbon black dispersions prepared with steam jet-cooked corn starch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utilization of jet-cooked waxy and normal corn starch to prepare aqueous dispersions of hydrophobic carbon black (Vulcan XC-72R) is reported. Blending carbon black (CB) into aqueous jet-cooked dispersions of starch followed by high pressure homogenization produced stable aqueous carbon black di...

  4. Retrievals of Dust and Black Carbon Radiative Forcing in Snow using Imaging Spectroscopy

    NASA Astrophysics Data System (ADS)

    Seidel, F. C.; Painter, T.; Bryant, A. C.; Skiles, M.; Rittger, K. E.

    2012-12-01

    The reduction of snow albedo due to impurities of dust and black carbon provides an additional energy flux into a snowpack. This positive radiative forcing accelerates snowmelt, reduces snow cover duration and water runoff. Extensive information in time and space on dust and black carbon radiative forcing in snow are therefore required to model and predict water availability from snow and ice reservoirs. We present a novel processing chain to retrieve dust and black carbon radiative forcing in snow from orthorectified remote sensing data. We use JPL's classic version of the Airborne Visible / Infrared Imaging Spectrometer (AVIRIS) to measure upwelling solar radiance at the sensor level. The first stage of processing comprises the modeling and compensation for atmospheric and topographic influences on the AVIRIS data. The resulting directional surface reflectance factor is used to determine snow cover and to retrieve the snow grain size distribution. The latter requires a simple inversion strategy using a look up table with pre-calculated values of spectral ice absorption features, which depend to the first order on the snow grain size. Spectral snow albedo is determined by generalizing the directional snow surface spectral reflectance with the anisotropy factor given by the bidirectional reflectance distribution function. The integration over the visible spectral range of solar light yields the broadband snow albedo. The difference of the latter with a modeled clean snow albedo multiplied by the irradiance provides the spatial distribution of the radiative forcing in snow. In addition, we validate the spectral irradiance and directional surface reflectance of snow against independent in-situ reference observations in the Senator Beck Basin Study Area, Upper Colorado River Basin, San Juan Mountains, Colorado, USA. The results indicate that the products derived from AVIRIS data enable us to retrieve and monitor quantitative snow surface properties relevant to

  5. Retention and clearance of inhaled submicron carbon black particles.

    PubMed

    Strom, K A; Johnson, J T; Chan, T L

    1989-01-01

    Carbon black aerosols were used as a probe of the pulmonary retention and clearance of submicron particles. Male Fischer rats (COBS CD) were exposed for 20 h/d, 7 d/wk for 1, 3, or 6 wk to either 7 +/- 2 mg/m3 carbon black or filtered air. The submicron aerosol (mass median aerodynamic diameter, MMAD, 0.24 microns) was generated with a Wright dust feed-cyclone system. Lung and hilar lymph node particle burdens were determined immediately following the exposure and at preselected intervals up to 1 yr postexposure. After 1-, 3-, and 6-wk exposures, the lung burdens were 1.1 +/- 0.1, 3.5 +/- 0.2, and 5.9 +/- 0.1 mg, respectively. One year after a 1-, 3-, or 6-wk exposure, 8%, 46%, and 61% of the initial lung burden remained in the lungs. Initially, the hilar lymph nodes contained 0.2%, 0.9%, and 2.0% of the lung burdens in the 3 exposure groups, respectively. At 1 yr postexposure, particle translocation from the lungs led to a rise in lymph node burdens to 1%, 21%, and 27% of the initial lung burden. The retention of carbon black in both the lungs and lymph nodes combined was 9%, 67%, and 89% for the 1-, 3-, and 6-wk exposed animals. Lung clearance was modeled as a compartmental system consisting of four lung compartments and a regional lymph node compartment. The results from the model are similar for carbon black and diesel engine exhaust particles. However, the compartmental kinetics of carbon black differed in two ways: the deposition efficiency in the alveolar region was lower than that for diesel exhaust particles, and there was earlier transport of particles to the regional lymph nodes. These results showed that when lung burdens reached 0.8 mg, lung clearance was decreased by 50% and lymphatic transport of insoluble particles was increased. PMID:2466129

  6. Black Carbon Concentration from Worldwide Aerosol Robotic Network (AERONET)

    NASA Technical Reports Server (NTRS)

    Schuster, Greg; Dubovik, Oleg; Holben, Brent; Clothiaux, Eugene

    2008-01-01

    Worldwide black carbon concentration measurements are needed to assess the efficacy of the carbon emissions inventory and transport model output. This requires long-term measurements in many regions, as model success in one region or season does not apply to all regions and seasons. AERONET is an automated network of more than 180 surface radiometers located throughout the world. The sky radiance measurements obtained by AERONET are inverted to provide column-averaged aerosol refractive indices and size distributions for the AERONET database, which we use to derive column-averaged black carbon concentrations and specific absorptions that are constrained by the measured radiation field. This provides a link between AERONET sky radiance measurements and the elemental carbon concentration of transport models without the need for an optics module in the transport model. Knowledge of both the black carbon concentration and aerosol absorption optical depth (i.e., input and output of the optics module) will enable improvements to the transport model optics module.

  7. Black Carbon Concentration from Worldwide Aerosol Robotic Network (AERONET) Measurements

    NASA Technical Reports Server (NTRS)

    Schuster, Gregory L.; Dubovik, Oleg; Holben, Brent N.; Clothiaux, Eugene E.

    2006-01-01

    The carbon emissions inventories used to initialize transport models and general circulation models are highly parameterized, and created on the basis of multiple sparse datasets (such as fuel use inventories and emission factors). The resulting inventories are uncertain by at least a factor of 2, and this uncertainty is carried forward to the model output. [Bond et al., 1998, Bond et al., 2004, Cooke et al., 1999, Streets et al., 2001] Worldwide black carbon concentration measurements are needed to assess the efficacy of the carbon emissions inventory and transport model output on a continuous basis.

  8. ENHANCED TOXICITY OF CHARGED CARBON NANOTUBES AND ULTRAFINE CARBON BLACK PARTICLES

    EPA Science Inventory

    Man-made carbonaceous nano-particles such as single and multi-walled carbon nano-tubes (CNT) and ultra-fine carbon black (UFCB) particles are finding increasing applications in industry, but their potential toxic effects is of concern. In aqueous media, these particles cluster in...

  9. Improving Aboveground Carbon Estimates in Dryland Ecosystems with Airborne LiDAR and Satellite Laser Altimetry

    NASA Astrophysics Data System (ADS)

    Glenn, N. F.; Shrestha, R.; Li, A.; Spaete, L.

    2014-12-01

    Numerous studies have demonstrated the utility of ground and airborne LiDAR data to quantify ecosystem structure. In addition, data from satellite-based laser altimetry (e.g. ICESat's GLAS instrument) have been used to estimate vegetation heights, aboveground carbon, and topography in forested areas. With the upcoming ICESAT-2 satellite scheduled to launch in 2017, we have the potential to map vegetation characteristics and dynamics in other ecosystems, including semiarid and low-height ecosystems, at global and regional scales. The ICESat-2 satellite will include the Advanced Topographic Laser Altimeter System (ATLAS) with a configuration of 6 laser beams with 532 nm wavelength and photon counting detectors. We will demonstrate the potential of ICESat-2 to provide estimates of vegetation structure and topography in a dryland ecosystem by simulating the configuration of the ATLAS mission. We will also examine how airborne LiDAR can be used together with ICESat-2 and other satellite data to achieve estimates of aboveground carbon. We will explore how these data may be used for future monitoring and quantification of spatial and temporal changes in aboveground carbon and topography.

  10. Dissolved black carbon in Antarctic lakes: Chemical signatures of past and present sources

    NASA Astrophysics Data System (ADS)

    Khan, Alia L.; Jaffé, Rudolf; Ding, Yan; McKnight, Diane M.

    2016-06-01

    The perennially ice-covered, closed-basin lakes in the McMurdo Dry Valleys, Antarctica, serve as sentinels for understanding the fate of dissolved black carbon from glacial sources in aquatic ecosystems. Here we show that dissolved black carbon can persist in freshwater and saline surface waters for thousands of years, while preserving the chemical signature of the original source materials. The ancient brines of the lake bottom waters have retained dissolved black carbon with a woody chemical signature, representing long-range transport of black carbon from wildfires. In contrast, the surface waters are enriched in contemporary black carbon from fossil fuel combustion. Comparison of samples collected 25 years apart from the same lake suggests that the enrichment in anthropogenic black carbon is recent. Differences in the chemical composition of dissolved black carbon among the lakes are likely due to biogeochemical processing such as photochemical degradation and sorption on metal oxides.

  11. Taking Stock of Circumboreal Forest Carbon With Ground Measurements, Airborne and Spaceborne LiDAR

    NASA Technical Reports Server (NTRS)

    Neigh, Christopher S. R.; Nelson, Ross F.; Ranson, K. Jon; Margolis, Hank A.; Montesano, Paul M.; Sun, Guoqing; Kharuk, Viacheslav; Naesset, Erik; Wulder, Michael A.; Andersen, Hans-Erik

    2013-01-01

    The boreal forest accounts for one-third of global forests, but remains largely inaccessible to ground-based measurements and monitoring. It contains large quantities of carbon in its vegetation and soils, and research suggests that it will be subject to increasingly severe climate-driven disturbance. We employ a suite of ground-, airborne- and space-based measurement techniques to derive the first satellite LiDAR-based estimates of aboveground carbon for the entire circumboreal forest biome. Incorporating these inventory techniques with uncertainty analysis, we estimate total aboveground carbon of 38 +/- 3.1 Pg. This boreal forest carbon is mostly concentrated from 50 to 55degN in eastern Canada and from 55 to 60degN in eastern Eurasia. Both of these regions are expected to warm >3 C by 2100, and monitoring the effects of warming on these stocks is important to understanding its future carbon balance. Our maps establish a baseline for future quantification of circumboreal carbon and the described technique should provide a robust method for future monitoring of the spatial and temporal changes of the aboveground carbon content.

  12. Potential climate impact of black carbon emitted by rockets

    NASA Astrophysics Data System (ADS)

    Ross, Martin; Mills, Michael; Toohey, Darin

    2010-12-01

    A new type of hydrocarbon rocket engine is expected to power a fleet of suborbital rockets for commercial and scientific purposes in coming decades. A global climate model predicts that emissions from a fleet of 1000 launches per year of suborbital rockets would create a persistent layer of black carbon particles in the northern stratosphere that could cause potentially significant changes in the global atmospheric circulation and distributions of ozone and temperature. Tropical stratospheric ozone abundances are predicted to change as much as 1%, while polar ozone changes by up to 6%. Polar surface temperatures change as much as one degree K regionally with significant impacts on polar sea ice fractions. After one decade of continuous launches, globally averaged radiative forcing from the black carbon would exceed the forcing from the emitted CO2 by a factor of about 105 and would be comparable to the radiative forcing estimated from current subsonic aviation.

  13. Final recommendations for reference materials in black carbon analysis

    NASA Astrophysics Data System (ADS)

    Schmidt, Michael W. I.; Masiello, Caroline A.; Skjemstad, Jan O.

    Last summer, a symposium was held to discuss aspects of global biogeochemical cycles, including organic matter cycling in soils, rivers, and marine environments; black carbon particle fluxes and the biological pump; dissolved organic matter; and organic matter preservation. Seventy scientists from various disciplines, including oceanography, soil science, geology, and chemistry attended the 3-day meeting at the Friday Harbor Laboratories, a research station of the University of Washington.“New Approaches in Marine Organic Biogeochemistry” commemorated the life and science of a colleague and friend, John I. Hedges, who was also involved in several groups developing chemical reference materials. Part of this symposium included a workshop on chemical reference materials, where final recommendations of the Steering Committee for Black Carbon Reference Materials were presented.

  14. Void morphology in polyethylene/carbon black composites

    SciTech Connect

    Marr, D.W.M.; Wartenberg, M.; Schwartz, K.B.

    1996-12-31

    A combination of small angle neutron scattering (SANS) and contrast matching techniques is used to determine the size and quantity of voids incorporated during fabrication of polyethylene/carbon black composites. The analysis used to extract void morphology from SANS data is based on the three-phase model of microcrack determination via small angle x-rayscattering (SAXS) developed by W.Wu{sup 12} and applied to particulate reinforced composites.

  15. The Black Lake (Quebec, Canada) mineral carbonation experimental station: CO2 capture in mine waste

    NASA Astrophysics Data System (ADS)

    Beaudoin, G.; Constantin, M.; Duchesne, J.; Dupuis, C.; Entrazi, A.; Gras, A.; Huot, F.; Fortier, R.; Hebert, R.; Larachi, F.; Lechat, K.; Lemieux, J. M.; Molson, J. W. H.; Maldague, X.; Therrien, R.; Assima, G. P.

    2014-12-01

    Passive mineral carbonation of chrysotile mining and milling waste was discovered at the Black Lake mine, southern Québec, 10 years ago. Indurated crusts were found at the surface and within waste piles where mineral and rock fragments are cemented by hydrated magnesium carbonates. A long-term research program has yielded significant insight into the process of CO2 capture from the atmosphere, and how it can be implemented during mining operations. Laboratory experiments show that the waste mineralogy is crucial, brucite being more reactive than serpentine. Partial water saturation, circa 40%, is also critical to dissolve magnesium from minerals, and transport aqueous CO2 to precipitation sites. Grain armoring by iron oxidation induced by dissolved oxygen prevents further reaction. Two experimental cells constructed with milling waste and fitted with various monitoring probes (T, H2O content, leachate) and gas sampling ports, have been monitored for more than 3 years, along with environmental conditions. The interstitial gas in the cells remains depleted in CO2 indicating continuous capture of ambient atmospheric CO2 at rates faster than advection to reaction sites. The energy released by the exothermic mineral carbonation reactions has been observed both in laboratory experiments (up to 4 °C) and in the field. Warm air, depleted to 10 ppmv CO2, vents at the surface of the waste piles, indicating reaction with atmospheric CO2 deep inside the piles. A thermal anomaly, detected by airborne infrared and coincident with a known venting area, was selected for locating a 100 m deep borehole fitted with sensor arrays to monitor active mineral carbonation within the pile. The borehole has intersected areas where mineral carbonation has indurated the milling waste. The borehole will be monitored for the next 3 years to better understand the mineral carbonation process, and its potential to yield recoverable geothermal energy in mining environments.

  16. Personal exposure to Black Carbon in transport microenvironments

    NASA Astrophysics Data System (ADS)

    Dons, Evi; Int Panis, Luc; Van Poppel, Martine; Theunis, Jan; Wets, Geert

    2012-08-01

    We evaluated personal exposure of 62 individuals to the air pollutant Black Carbon, using 13 portable aethalometers while keeping detailed records of their time-activity pattern and whereabouts. Concentrations encountered in transport are studied in depth and related to trip motives. The evaluation comprises more than 1500 trips with different transport modes. Measurements were spread over two seasons. Results show that 6% of the time is spent in transport, but it accounts for 21% of personal exposure to Black Carbon and approximately 30% of inhaled dose. Concentrations in transport were 2-5 times higher compared to concentrations encountered at home. Exposure was highest for car drivers, and car and bus passengers. Concentrations of Black Carbon were only half as much when traveling by bike or on foot; when incorporating breathing rates, dose was found to be twice as high for active modes. Lowest 'in transport' concentrations were measured in trains, but nevertheless these concentrations are double the concentrations measured at home. Two thirds of the trips are car trips, and those trips showed a large spread in concentrations. In-car concentrations are higher during peak hours compared to off-peak, and are elevated on weekdays compared to Saturdays and even more so on Sundays. These findings result in significantly higher exposure during car commute trips (motive 'Work'), and lower concentrations for trips with motive 'Social and leisure'. Because of the many factors influencing exposure in transport, travel time is not a good predictor of integrated personal exposure or inhaled dose.

  17. Measuring black carbon spectral extinction in the visible and infrared

    NASA Astrophysics Data System (ADS)

    Smith, A. J. A.; Peters, D. M.; McPheat, R.; Lukanihins, S.; Grainger, R. G.

    2015-09-01

    This work presents measurements of the spectral extinction of black carbon aerosol from 400 nm to 15 μm. The aerosol was generated using a Miniature Combustion Aerosol Standard soot generator and then allowed to circulate in an aerosol cell where its extinction was measured using a grating spectrometer in the visible and a Fourier transform spectrometer in the infrared. Size distribution, number concentration, and mass extinction cross sections have also been obtained using single-particle aerosol samplers. A mean mass extinction cross section at 550 nm of 8.3 ± 1.6 m2 g-1 is found which, assuming a reasonable single scatter albedo of 0.2, corresponds to a mass absorption cross section of 6.6 ± 1.3 m2 g-1. This compares well with previously reported literature values. Computer analysis of electron microscope images of the particles provides independent confirmation of the size distribution as well as fractal parameters of the black carbon aerosol. The aerosol properties presented in this work are representative of very fresh, uncoated black carbon aerosol. After atmospheric processing of such aerosols (which could include mixing with other constituents and structural changes), different optical properties would be expected.

  18. Barrow Black Carbon Source and Impact Study Final Campaign Report

    SciTech Connect

    Barrett, Tate

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact (BBCSI) Study was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement site in Barrow, AK. The carbonaceous component was characterized via measurement of the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the particulate matter, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine (PM2.5) and 49 coarse (PM10) particulate matter fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the BBCSI used standard Tisch hi-vol motors which have a known lifetime of ~1 month under constant use; this necessitated monthly maintenance and it is suggested that the motors be upgraded to industrial blowers for future deployment in the Arctic. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric particulate matter samples from Barrow, AK from July 2012 to June 2013. Preliminary analysis of the organic and black carbon concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer.

  19. Detection of airborne carbon nanotubes based on the reactivity of the embedded catalyst.

    PubMed

    Neubauer, N; Kasper, G

    2015-01-01

    A previously described method for detecting catalyst particles in workplace air((1,2)) was applied to airborne carbon nanotubes (CNT). It infers the CNT concentration indirectly from the catalytic activity of metallic nanoparticles embedded as part of the CNT production process. Essentially, one samples airborne CNT onto a filter enclosed in a tiny chemical reactor and then initiates a gas-phase catalytic reaction on the sample. The change in concentration of one of the reactants is then determined by an IR sensor as measure of activity. The method requires a one-point calibration with a CNT sample of known mass. The suitability of the method was tested with nickel containing (25 or 38% by weight), well-characterized multi-walled CNT aerosols generated freshly in the lab for each experiment. Two chemical reactions were investigated, of which the oxidation of CO to CO2 at 470°C was found to be more effective, because nearly 100% of the nickel was exposed at that temperature by burning off the carbon, giving a linear relationship between CO conversion and nickel mass. Based on the investigated aerosols, a lower detection limit of 1 μg of sampled nickel was estimated. This translates into sampling times ranging from minutes to about one working day, depending on airborne CNT concentration and catalyst content, as well as sampling flow rate. The time for the subsequent chemical analysis is on the order of minutes, regardless of the time required to accumulate the sample and can be done on site. PMID:25271474

  20. Analysis of Transpacific Transport of Black Carbon during HIPPO-3 and Implications for Black Carbon Aging

    NASA Astrophysics Data System (ADS)

    Shen, Z.; Liu, J.; Horowitz, L. W.; Henze, D. K.; Gao, R.; Lin, J.; Tao, S.

    2013-12-01

    Long-range transport of black carbon (BC) is a growing concern as a result of the great effect of BC on climate change and air quality. We study transpacific transport of BC during HIPPO-3 based on a combination of inverse modeling and sensitivity analysis. We use the GEOS-Chem Model and its adjoint to estimate the origin of BC over the North Pacific and constrain Asian BC emissions. We find that the sources of BC transported to the North Pacific in March and April, 2010 are different. While biomass burning in Southeast Asia contributes about 60% of BC in March, more than 90% BC comes from fossil fuel and biofuel combustion in East Asia in April. GEOS-Chem model generally resolves the spatial and temporal variation of BC concentrations over the North Pacific, but is unable to reproduce the low end and high end of BC observations. We find that using the optimized BC emissions derived from inverse modeling cannot significantly improve model simulations. This indicates that uncertainties remaining in BC transport account for the major biases in BC simulations. The aging process is one of the key factors controlling the wet scavenging and remote concentrations of BC. We conduct several sensitivity tests on BC aging and find that the aging time scale of anthropogenic BC is several hours, smaller than the values used in most global models, while the aging process of biomass burning BC may occur much slower on a time scale of a few days. To evaluate the effect of BC aging and wet deposition on transpacific transport of BC, we develop an idealized BC transport model. We find that the mid-latitude air mass captured by HIPPO-3 aircraft may experience a series of precipitation events, particularly near the East Asia source region. Therefore, transpacific transport of BC is sensitive to BC aging when the aging rate is fast, and the effect of the aging process peaks when the aging time scale is in the range of 1-1.5 d. This further indicates that BC aging close to the sources

  1. Analysis of transpacific transport of black carbon during HIPPO-3: implications for black carbon aging

    NASA Astrophysics Data System (ADS)

    Shen, Z.; Liu, J.; Horowitz, L. W.; Henze, D. K.; Fan, S.; Levy, H., II; Mauzerall, D. L.; Lin, J.-T.; Tao, S.

    2014-01-01

    Long-range transport of black carbon (BC) is a growing concern as a result of the efficiency of BC in warming the climate and its adverse impact on human health. We study transpacific transport of BC during HIPPO-3 using a combination of inverse modeling and sensitivity analysis. We use the GEOS-Chem chemical transport model and its adjoint to constrain Asian BC emissions and estimate the source of BC over the North Pacific. We find that different sources of BC dominate the transport to the North Pacific during the southbound (29 March 2010) and northbound (13 April 2010) measurements in HIPPO-3. While biomass burning in Southeast Asia (SE) contributes about 60% of BC in March, more than 90% of BC comes from fossil fuel and biofuel combustion in East Asia (EA) during the April mission. GEOS-Chem simulations generally resolve the spatial and temporal variation of BC concentrations over the North Pacific, but are unable to reproduce the low and high tails of the observed BC distribution. We find that the optimized BC emissions derived from inverse modeling fail to improve model simulations significantly. This failure indicates that uncertainties in BC transport, rather than in emissions, account for the major biases in GEOS-Chem simulations of BC. The aging process, transforming BC from hydrophobic into hydrophilic form, is one of the key factors controlling wet scavenging and remote concentrations of BC. Sensitivity tests on BC aging suggest that the aging time scale of anthropogenic BC from EA is several hours, faster than assumed in most global models, while the aging process of biomass burning BC from SE may occur much slower, with a time scale of a few days. To evaluate the effects of BC aging and wet deposition on transpacific transport of BC, we develop an idealized model of BC transport. We find that the mid-latitude air masses sampled during HIPPO-3 may have experienced a series of precipitation events, particularly near the EA and SE source region

  2. Analysis of transpacific transport of black carbon during HIPPO-3: implications for black carbon aging

    NASA Astrophysics Data System (ADS)

    Shen, Z.; Liu, J.; Horowitz, L. W.; Henze, D. K.; Fan, S.; Levy, H., II; Mauzerall, D. L.; Lin, J.-T.; Tao, S.

    2014-06-01

    Long-range transport of black carbon (BC) is a growing concern as a result of the efficiency of BC in warming the climate and its adverse impact on human health. We study transpacific transport of BC during HIPPO-3 using a combination of inverse modeling and sensitivity analysis. We use the GEOS-Chem chemical transport model and its adjoint to constrain Asian BC emissions and estimate the source of BC over the North Pacific. We find that different sources of BC dominate the transport to the North Pacific during the southbound (29 March 2010) and northbound (13 April 2010) measurements in HIPPO-3. While biomass burning in Southeast Asia (SE) contributes about 60% of BC in March, more than 90% of BC comes from fossil fuel and biofuel combustion in East Asia (EA) during the April mission. GEOS-Chem simulations generally resolve the spatial and temporal variation of BC concentrations over the North Pacific, but are unable to reproduce the low and high tails of the observed BC distribution. We find that the optimized BC emissions derived from inverse modeling fail to improve model simulations significantly. This failure indicates that uncertainties in BC removal as well as transport, rather than in emissions, account for the major biases in GEOS-Chem simulations of BC over the North Pacific. The aging process, transforming BC from hydrophobic into hydrophilic form, is one of the key factors controlling wet scavenging and remote concentrations of BC. Sensitivity tests on BC aging (ignoring uncertainties of other factors controlling BC long range transport) suggest that in order to fit HIPPO-3 observations, the aging timescale of anthropogenic BC from EA may be several hours (faster than assumed in most global models), while the aging process of biomass burning BC from SE may occur much slower, with a timescale of a few days. To evaluate the effects of BC aging and wet deposition on transpacific transport of BC, we develop an idealized model of BC transport. We find that

  3. Double-Pulse Two-micron LPDA Lidar Simulation for Airborne Carbon Dioxide Measurements

    NASA Astrophysics Data System (ADS)

    Refaat, Tamer F.; Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta

    2016-06-01

    An advanced double-pulse 2-μm integrated path differential absorption lidar has been developed at NASA Langley Research Center for measuring atmospheric carbon dioxide. The instrument utilizes a state-of-the-art 2-μm laser transmitter with tunable on-line wavelength and advanced receiver. Instrument modeling and airborne simulations are presented in this paper. Focusing on random errors, results demonstrate instrument capabilities of performing precise carbon dioxide differential optical depth measurement with less than 3% random error for single-shot operation up to 11 km altitude. This study is useful for defining CO2 measurement weighting function for adaptive targeting, instrument setting, validation and sensitivity trade-offs.

  4. Airborne Carbon Dioxide Laser Absorption Spectrometer for IPDA Measurements of Tropospheric CO2: Recent Results

    NASA Technical Reports Server (NTRS)

    Spiers, Gary D.; Menzies, Robert T.

    2008-01-01

    The National Research Council's decadal survey on Earth Science and Applications from Space[1] recommended the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission for launch in 2013-2016 as a logical follow-on to the Orbiting Carbon Observatory (OCO) which is scheduled for launch in late 2008 [2]. The use of a laser absorption measurement technique provides the required ability to make day and night measurements of CO2 over all latitudes and seasons. As a demonstrator for an approach to meeting the instrument needs for the ASCENDS mission we have developed the airborne Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) which uses the Integrated Path Differential Absorption (IPDA) Spectrometer [3] technique operating in the 2 micron wavelength region.. During 2006 a short engineering checkout flight of the CO2LAS was conducted and the results presented previously [4]. Several short flight campaigns were conducted during 2007 and we report results from these campaigns.

  5. Verification of engineering assumptions in modeling of airborne release of Carbon-14

    SciTech Connect

    Simonson, S.A.; Yim, Man-Sung

    1996-10-01

    The effects of atmospheric pressure variation on the flow velocity, water vapor transport, and oxygen depletion within a hypothetical low-level engineered waste facility were recently modeled with a set of engineering assumptions. The model that resulted from these activates is termed {open_quotes}GETAR{close_quote} for gas evolution, transport and reaction. Results of transport calculations show that the pumping effect of barometric pressure changes is the dominant mechanism for inducing the release of carbon-14 in a facility with a monitoring well. Coupled with this calculation, are recent results that indicate that a greater fraction of the carbon-14 within a hypothetical waste facility would be available for biodegradation and release via an airborne pathway rather than into groundwater.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Deposition of black carbon (BC) on snow and ice is widely considered to have a climate warming effect by reducing the surface albedo and promoting snowmelt. Such positive climate feedbacks in the Arctic are especially problematic because rising surface temperatures may trigger the release of large Arctic stores of terrestrial carbon, further amplifying current warming trends. Recognizing the Arctic as a vulnerable region, the U.S. government committed funds in Copenhagen in 2009 for international cooperation targeting Arctic BC emissions reductions. As a result, the U.S. Department of State has funded three research and demonstration projects with the goal to better understand and mitigate BC deposition in the Russian Arctic from a range of sources. The U.S. Department of Energy's (DOE) Arctic BC initiative presented here is focused on mitigating BC emissions resulting from heat and power generation as well as industrial applications. A detailed understanding of BC sources and its transport and fate is required to prioritize efforts to reduce BC emissions from sources that deposit in the Russian Arctic. Sources of BC include the combustion of fossil fuels (e.g. coal, fuel oil, diesel) and the combustion of biomass (e.g. wildfires, agricultural burning, residential heating and cooking). Information on fuel use and associated emissions from the industrial and heat & power sectors in Russia is scarce and difficult to obtain from the open literature. Hence, our project includes a research component designed to locate Arctic BC emissions sources in Russia and determine associated BC transport patterns. We use results from the research phase to inform a subsequent assessment/demonstration phase. We use a back-trajectory modeling method (potential source contribution function - PSCF), which combines multi-year, high-frequency measurements with knowledge about atmospheric transport patterns. The PSCF modeling allows us to map the probability (by season and year) at course

  7. Effect of Pt and Fe catalysts in the transformation of carbon black into carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Asokan, Vijayshankar; Myrseth, Velaug; Kosinski, Pawel

    2015-06-01

    In this research carbon nanotubes and carbon nano onion-like structures were synthesized from carbon black using metal catalysts at 400 °C and 700 °C. Platinum and iron-group metals were used as catalysts for the transformation of CB into graphitized nanocarbon and the effect of both metals was compared. The synthesized products were characterized using X-ray diffraction (XRD), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM) and Raman spectroscopy. The characterization shows that this process is very efficient in the synthesis of high quality graphitized products from amorphous carbon black, even though the process temperature was relatively low in comparison with previous studies. Distinguished graphitic walls of the newly formed carbon nanostructures were clearly visible in the HRTEM images. Possible growth difference related to the type of catalyst used is briefly explained with the basis of electron vacancies in d-orbitals of metals.

  8. Black carbon in grassland ecosystems of the world

    NASA Astrophysics Data System (ADS)

    Rodionov, Andrej; Amelung, Wulf; Peinemann, Norman; Haumaier, Ludwig; Zhang, Xudong; Kleber, Markus; Glaser, Bruno; Urusevskaya, Inga; Zech, Wolfgang

    2010-09-01

    Black carbon (BC) is the product of incomplete burning processes and a significant component of the passive soil organic carbon (SOC) pool. The role of BC in the global carbon cycle is still unclear. This study aimed to quantify and characterize BC in major grassland ecosystems of the world. Twenty-eight representative soil profiles (mainly Mollisols) were sampled in the Russian Steppe, the U.S. Great Plains, the Argentinian Pampa, the Manchurian Plains in China, and the Chernozem region in central Germany. Black carbon contents were estimated using benzene polycarboxylic acids (BPCA) as a molecular marker, and indications about the origin of the BC were derived from bulk and compound-specific δ13C analyses and radiocarbon dating of bulk soil organic matter (SOM). Our findings suggest that between 5% and 30% of SOC stocks consist of BC. Maximum BC contributions to SOC frequently were found at deeper parts of the A horizon with 14C ages younger than 7000 years BP; that is, incorporation of C as charred particles accompanied ecosystem development since the mid-Holocene. Most of this BC formed from local vegetation, as indicated by a 13C isotope signature similar to that of bulk SOM. At some sites, also nonlocal sources contributed to soil BC, e.g., fossil fuel BC inputs at the German sites. Black carbon stocks were highest in Chernozems and lowest in Kastanozems. The Russian Steppe and Chinese Manchurian sites stored about 3-4 times more BC (around 3 kg m-2) than did the other sites because of thicker A horizons that were rich in BC. On a global scale, we estimate that steppe ecosystems contain between 4 and 17 Pg BC.

  9. Exposure assessment to airborne endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide in open style swine houses.

    PubMed

    Chang, C W; Chung, H; Huang, C F; Su, H J

    2001-08-01

    Information is limited for the exposure levels of airborne hazardous substances in swine feed buildings that are not completely enclosed. Open-style breeding, growing and finishing swine houses in six farms in subtropical Taiwan were studied for the airborne concentrations of endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide. The air in the farrowing and nursery stalls as partially enclosed was also simultaneously evaluated. Three selected gases and airborne dusts were quantified respectively by using Drager diffusion tubes and a filter-weighing method. Endotoxin was analyzed by the Limulus amoebocyte lysate assay. Average concentration of airborne total endotoxin among piggeries was between 36.8 and 298 EU/m(3), while that for respirable endotoxin was 14.1-129 EU/m(3). Mean concentration of total dust was between 0.15 and 0.34 mg/m(3), with average level of respirable dust of 0.14 mg/m(3). The respective concentrations of NH3, CO2 and H2S were less than 5 ppm, 600-895 ppm and less than 0.2 ppm. Airborne concentrations of total dust and endotoxin in the nursery house were higher than in the other types of swine houses. The finishing house presented the highest exposure risk to NH3, CO2 and H2S. Employees working in the finishing stalls were also exposed to the highest airborne levels of respirable endotoxin and dust. On the other hand, the air of the breeding units was the least contaminated in terms of airborne endotoxin, dust, NH3, CO2 and H2S. The airborne concentrations of substances measured in the present study were all lower than most of published studies conducted in mainly enclosed swine buildings. Distinct characteristics, including maintaining swine houses in an open status and frequent spraying water inside the stalls, significantly reduce accumulation of gases and airborne particulates. PMID:11513795

  10. Peat Depth Assessment Using Airborne Geophysical Data for Carbon Stock Modelling

    NASA Astrophysics Data System (ADS)

    Keaney, Antoinette; McKinley, Jennifer; Ruffell, Alastair; Robinson, Martin; Graham, Conor; Hodgson, Jim; Desissa, Mohammednur

    2013-04-01

    The Kyoto Agreement demands that all signatory countries have an inventory of their carbon stock, plus possible future changes to this store. This is particularly important for Ireland, where some 16% of the surface is covered by peat bog. Estimates of soil carbon stores are a key component of the required annual returns made by the Irish and UK governments to the Intergovernmental Panel on Climate Change. Saturated peat attenuates gamma-radiation from underlying rocks. This effect can be used to estimate the thickness of peat, within certain limits. This project examines this relationship between peat depth and gamma-radiation using airborne geophysical data generated by the Tellus Survey and newly acquired data collected as part of the EU-funded Tellus Border project, together encompassing Northern Ireland and the border area of the Republic of Ireland. Selected peat bog sites are used to ground truth and evaluate the use of airborne geophysical (radiometric and electromagnetic) data and validate modelled estimates of soil carbon, peat volume and depth to bedrock. Data from two test line sites are presented: one in Bundoran, County Donegal and a second line in Sliabh Beagh, County Monaghan. The plane flew over these areas at different times of the year and at a series of different elevations allowing the data to be assessed temporally with different soil/peat saturation levels. On the ground these flight test lines cover varying surface land use zones allowing future extrapolation of data from the sites. This research applies spatial statistical techniques, including uncertainty estimation in geostatistical prediction and simulation, to investigate and model the use of airborne geophysical data to examine the relationship between reduced radioactivity and peat depth. Ground truthing at test line locations and selected peat bog sites involves use of ground penetrating radar, terrestrial LiDAR, peat depth probing, magnetometry, resistivity, handheld gamma

  11. Solid fuel production by hydrothermal carbonization of black liquor.

    PubMed

    Kang, Shimin; Li, Xianglan; Fan, Juan; Chang, Jie

    2012-04-01

    Formaldehyde was used as a polymerization agent to perform hydrothermal carbonization of black liquor for solid fuel production from 220 to 285°C. Compared to hydrochar prepared without formaldehyde, hydrochar produced in the presence of a 2.8wt.% formaldehyde solution (hydrochar-F) had 1.27-2.13 times higher yield, 1.02-1.36 times higher heating value (HHV), 1.20-2.31 times higher C recovery efficiency, 1.20-2.44 times higher total energy recovery efficiency, 0.51-0.64 times lower sulfur content, and 0.48-0.89 times lower ash content. The HHV of hydrochar-Fs ranged from 2.2×10(4) to 3.0×10(4)kJ/kg, while the HHV of hydrochar-F produced at 285°C was 1.90 times greater than that of the raw material (black liquor solid). These considerable improvements indicated that formaldehyde was an effective additive in hydrothermal carbonization of black liquor. PMID:22330593

  12. Characterization of carbon black modified by maleic acid

    NASA Astrophysics Data System (ADS)

    Asokan, Vijayshankar; Kosinski, Pawel; Skodvin, Tore; Myrseth, Velaug

    2013-09-01

    We present here a method for modifying the surface of carbon black (CB) using a simple heat treatment in the presence of a carboxylic acid as well as water or ethylene glycol as a solvent. CB was mixed with maleic acid and either water or ethylene glycol, and heated at 250°C. Unlike the traditional surface modification processes which use heat treatment of carbon with mineral acids the present modification method using a carboxylic acid proved to be simple and time efficient. CB from two different vendors was used, and the modified samples were characterized by TGA, BET surface area measurement, XRD, particle size and zeta potential measurements, and FTIR. It was found that several material properties, including thermal stability and surface area, of the modified CB are significantly altered relative to the parental carbon samples. This method provides a rapid and simple route to tailor new materials with desired properties.

  13. Using Airborne and Satellite Imagery to Distinguish and Map Black Mangrove

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reports the results of studies evaluating color-infrared (CIR) aerial photography, CIR aerial true digital imagery, and high resolution QuickBird multispectral satellite imagery for distinguishing and mapping black mangrove [Avicennia germinans (L.) L.] populations along the lower Texas g...

  14. Black carbon and particulate matter (PM2.5) concentrations in New York City's subway stations.

    PubMed

    Vilcassim, M J Ruzmyn; Thurston, George D; Peltier, Richard E; Gordon, Terry

    2014-12-16

    The New York City (NYC) subway is the main mode of transport for over 5 million passengers on an average weekday. Therefore, airborne pollutants in the subway stations could have a significant impact on commuters and subway workers. This study looked at black carbon (BC) and particulate matter (PM2.5) concentrations in selected subway stations in Manhattan. BC and PM2.5 levels were measured in real time using a Micro-Aethalometer and a PDR-1500 DataRAM, respectively. Simultaneous samples were also collected on quartz filters for organic and elemental carbon (OC/EC) analysis and on Teflon filters for gravimetric and trace element analysis. In the underground subway stations, mean real time BC concentrations ranged from 5 to 23 μg/m(3), with 1 min average peaks >100 μg/m(3), while real time PM2.5 levels ranged from 35 to 200 μg/m(3). Mean EC levels ranged from 9 to 12.5 μg/m(3). At street level on the same days, the mean BC and PM2.5 concentrations were below 3 and 10 μg/m(3), respectively. This study shows that both BC soot and PM levels in NYC's subways are considerably higher than ambient urban street levels and that further monitoring and investigation of BC and PM subway exposures are warranted. PMID:25409007

  15. Birchwood biochar as partial carbon black replacement in styrene-butadiene rubber composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Birchwood feedstock was used to make slow pyrolysis biochar that contained 89% carbon and < 2% ash. This biochar was blended with carbon black as filler for styrene-butadiene rubber. Composites made from blended fillers of 25/75 biochar/carbon black were equivalent to or superior to their 100% carbo...

  16. Roles of black carbon on the fate of heavy metals and agrochemicals in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Char(coal) and other black carbon materials can comprise up to 35% of total organic carbon in US agricultural soils, and are known to strongly and often irreversibly bind contaminants including heavy metals. Black carbon has received renewed interests in recent years as a solid co-product formed du...

  17. Mapping Above- and Below-Ground Carbon Pools in Boreal Forests: The Case for Airborne Lidar.

    PubMed

    Kristensen, Terje; Næsset, Erik; Ohlson, Mikael; Bolstad, Paul V; Kolka, Randall

    2015-01-01

    A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and spatial distribution of C pools within and among multilayered Norway spruce (Picea abies) stands. Predictor variables from lidar derived metrics delivered precise models of above- and below-ground tree C, which comprised the largest C pool in our study stands. We also found evidence that lidar canopy data correlated well with the variation in field layer C stock, consisting mainly of ericaceous dwarf shrubs and herbaceous plants. However, lidar metrics derived directly from understory echoes did not yield significant models. Furthermore, our results indicate that the variation in both the mosses and soil organic layer C stock plots appears less influenced by differences in stand structure properties than topographical gradients. By using topographical models from lidar ground returns we were able to establish a strong correlation between lidar data and the organic layer C stock at a stand level. Increasing the topographical resolution from plot averages (~2000 m2) towards individual grid cells (1 m2) did not yield consistent models. Our study demonstrates a connection between the size and distribution of different forest C pools and models derived from airborne lidar data, providing a foundation for future research concerning the use of lidar for assessing and monitoring boreal forest C. PMID:26426532

  18. Mapping Above- and Below-Ground Carbon Pools in Boreal Forests: The Case for Airborne Lidar

    PubMed Central

    Kristensen, Terje; Næsset, Erik; Ohlson, Mikael; Bolstad, Paul V.; Kolka, Randall

    2015-01-01

    A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and spatial distribution of C pools within and among multilayered Norway spruce (Picea abies) stands. Predictor variables from lidar derived metrics delivered precise models of above- and below-ground tree C, which comprised the largest C pool in our study stands. We also found evidence that lidar canopy data correlated well with the variation in field layer C stock, consisting mainly of ericaceous dwarf shrubs and herbaceous plants. However, lidar metrics derived directly from understory echoes did not yield significant models. Furthermore, our results indicate that the variation in both the mosses and soil organic layer C stock plots appears less influenced by differences in stand structure properties than topographical gradients. By using topographical models from lidar ground returns we were able to establish a strong correlation between lidar data and the organic layer C stock at a stand level. Increasing the topographical resolution from plot averages (~2000 m2) towards individual grid cells (1 m2) did not yield consistent models. Our study demonstrates a connection between the size and distribution of different forest C pools and models derived from airborne lidar data, providing a foundation for future research concerning the use of lidar for assessing and monitoring boreal forest C. PMID:26426532

  19. Development of an Airborne System for Direct Validation of Regional Carbon Flux Estimates

    NASA Astrophysics Data System (ADS)

    Wolfe, G.; Kawa, S. R.; Hanisco, T. F.; Newman, P. A.

    2015-12-01

    Global distributions of greenhouse gas (GHG) sources and sinks, principally CO2 and CH4, and characterization of the processes that control them, comprise a key uncertainty in projections of future climate. A broad spectrum of tools is currently used to characterize these processes. Top-down inversions of orbital GHG column observations (e.g. ACOS/GOSAT and OCO-2) provide a global perspective, but little information is available to validate these estimates. Indirect (boundary-layer budget) or direct (tower-based eddy covariance) surface flux measurements can provide bottom-up constraints, but the former is typically focused on large point and area emission sources while the latter relies on sparse networks with limited spatial coverage. Aircraft are an ideal platform to bridge the flux representation scale from kilometers (as measured from towers) to the tens or hundreds of kilometers relevant to satellite observations and global models. In light of current measurement gaps and the emerging need for direct validation of GHG surface flux estimates, NASA is developing a sophisticated facility for airborne eddy covariance observations of carbon dioxide, methane, water vapor and other trace gases. Three components comprise the core measurement system: i) the NASA Wallops Sherpa, which is ideal for airborne eddy covariance due to its substantial payload and the ability to fly low and slow, ii) commercial GHG sensors optimized for airborne flux measurements, and iii) a custom gust-probe system for high-fidelity measurements of vertical wind velocity. These systems will be discussed in detail, along with future plans for deployment and application of measurements to improving GHG flux estimates on local, regional and global scales.

  20. The relationship between black carbon concentration and black smoke: A more general approach

    NASA Astrophysics Data System (ADS)

    Heal, Mathew R.; Quincey, Paul

    2012-07-01

    The black carbon (BC) component of ambient particulate matter is an important marker for combustion sources and for its impact on human health and radiative forcing. Extensive data archives exist for the black smoke metric, the historic measure of ambient particle darkness. An expression presented in earlier publications (Quincey, 2007; Quincey et al., 2011) for estimating BC concentrations from traditional black smoke measurements is shown to have limitations that can be addressed by using a more systematic approach to the issue of corrections for increasing darkening of the filter. The form of the more general relationship is shown to be an off-axis parabola rather than the on-axis parabola of the earlier work. Existing data from co-located black smoke and aethalometer measurements at 5 UK sites are reanalysed in this context. At very low concentrations of dark particles (British Black Smoke index < ˜10 μg m-3) a simple linear relationship BC (/μg m-3) ≈ 0.27·BSIBRITISH will suffice. A parabolic relationship, [BC/μgm]=√{5.2-1.1+1.5×BSI+62-13+19}-7.9-0.9+1.1, quantitatively similar to the previously published relationship will be more reliable for BSIBRITISH values up to 20-25 μg m-3. The full set of data available was fitted empirically to the off-axis parabola over the range 0-80 μg m-3 as the quadratic: [BC/μg m-3] = (0.27 ± 0.03) · BSIBRITISH - (4.0 ± 0.2) × 10-4(BSIBRITISH)2, but this curve is highly dependent on the variations between the individual data sets. Adding the extra complexity of the full off-axis parabolic relationship is unlikely to be justified in practical situations. All expressions apply also to the OECD definition of black smoke with the substitution BSIBRITISH = 0.85·BSIOECD. However, in common with the previous approach, they apply only to black smoke values obtained from standard black smoke samplers with 25 mm diameter filters and ˜2 m3 day-1 volumetric flow rate, and presume a value 16.6 m2 g-1 for the specific

  1. Carbon content of common airborne fungal species and fungal contribution to aerosol organic carbon in a subtropical city

    NASA Astrophysics Data System (ADS)

    Cheng, Jessica Y. W.; Chan, Chak K.; Lee, C.-T.; Lau, Arthur P. S.

    Interest in the role and contribution of fungi to atmospheric aerosols and processes grows in the past decade. Substantial data or information such as fungal mass or carbon loading to ambient aerosols is however still lacking. This study aimed to quantify the specific organic carbon content (OC per spore) of eleven fungal species commonly found airborne in the subtropics, and estimated their contribution to organic carbon in aerosols. The specific OC contents showed a size-dependent relationship ( r = 0.64, p < 0.05) and ranged from 3.6 to 201.0 pg carbon per spore or yeast cell, giving an average of 6.0 pg carbon per spore (RSD 51%) for spore or cell size less than 10 μm. In accounting for natural variations in the composition and abundance of fungal population, weighted-average carbon content for field samples was adopted using the laboratory determined specific OC values. An average of 5.97 pg carbon per spore (RSD 3.8%) was enumerated from 28 field samples collected at the university campus. The mean fungal OC concentration was 3.7, 6.0 and 9.7 ng m -3 in PM 2.5, PM 2.5-10 and PM 10, respectively. These corresponded to 0.1%, 1.2% and 0.2% of the total OC in PM 2.5, PM 2.5-10 and PM 10, respectively. In the study period, rain provided periods with low total OC but high fungal prevalence and fungi contributed 7-32% OC in PM 2.5-10 or 2.4-7.1% OC in PM 10. More extensive studies are deserved to better understand the spatial-, temporal- and episodic dependency on the fungal OC contribution to the atmospheric aerosols.

  2. Black Carbon in Estuarine and Coastal Ocean Dissolved Organic Matter

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Black carbon (BC) in ultrafiltered high-molecular-weight DOM (UDOM) was measured in surface waters of Delaware Bay, Chesapeake Bay and the adjacent Atlantic Ocean (USA) to ascertain the importance of riverine and estuarine DOM as a source of BC to the ocean. BC comprised 5-72% of UDOM-C (27+/-l7%) and on average 8.9+/-6.5% of dissolved organic carbon (DOC) with higher values in the turbid region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of Delaware Bay suggest that the higher levels of BC in surface water UDOM originated from localized sources, possibly from atmospheric deposition or released from resuspended sediments. Black carbon comprised 4 to 7% of the DOC in the coastal Atlantic Ocean, revealing that river-estuary systems are important exporters of colloidal BC to the ocean. The annual flux of BC from Delaware Bay UDOM to the Atlantic Ocean was estimated at 2.4x10(exp 10) g BC yr(exp -1). The global river flux of BC through DOM to the ocean could be on the order of 5.5x1O(exp 12)g BC yr (exp -1). These results support the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition.

  3. Relation between CO and Black Carbon from Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Park, S. S.; Kim, J.; Lim, H.; Mok, J.

    2014-12-01

    The Black Carbon (BC) is designated by one of the potential factor for global warming (IPCC, 2007). Furthermore, carbon monoxide (CO) is also important gas to modify chemical, physical and climatological properties of tropospheric chemistry. Both CO and carbonaceous aerosol, especial to the black carbon, are similar emission sources, fuel combustion and biomass burning. Previously, the MODIS-OMI algorithm (MOA) identified the BC amount and its location by using Angstrom Exponent (AE) from MODIS and Aerosol Index (AI) from OMI. In addition, the CO amount has been traced by the Measurement of Pollution in the Troposphere (MOPITT) since 1999. Therefore, the correlation between the AOD of BC (AODBC) and total column densities of CO (TCDCO) can be estimated by MOA and MOPITT. The correlation between AODBC and TCDCO becomes better than that between fine mode AOD and TCDCO in most global regions. Highly correlated case is the region with biomass burning and wild fires. In Southern Africa, however, the correlation coefficient between AODBC and TCDCO is lower than those between fine mode AOD and TCDCO. It is explained by the characteristics of wind fields, sources of aerosols, and distance from the source regions from the difference in the correlation. The results from correlation studies propose the possibilities that CO can be used as surrogates of BC and reference of the validation for the aerosol classification algorithm of BC from satellite measurements.

  4. Carbonaceous aerosols influencing atmospheric radiation: Black and organic carbon

    SciTech Connect

    Penner, J.E.

    1994-09-01

    Carbonaceous particles in the atmosphere may both scatter and absorb solar radiation. The fraction associated with the absorbing component is generally referred to as black carbon (BC) and is mainly produced from incomplete combustion processes. The fraction associated with condensed organic compounds is generally referred to as organic carbon (OC) or organic matter and is mainly scattering. Absorption of solar radiation by carbonaceous aerosols may heat the atmosphere, thereby altering the vertical temperature profile, while scattering of solar radiation may lead to a net cooling of the atmosphere/ocean system. Carbonaceous aerosols may also enhance the concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the fine particle (D < 2.5 {mu}m) source rates of both OC and BC. The source rates for anthropogenic organic aerosols may be as large as the source rates for anthropogenic sulfate aerosols, suggesting a similar magnitude of direct forcing of climate. The role of BC in decreasing the amount of reflected solar radiation by OC and sulfates is discussed. The total estimated forcing depends on the source estimates for organic and black carbon aerosols which are highly uncertain. The role of organic aerosols acting as cloud condensation nuclei (CCN) is also described.

  5. Biomass burning in boreal forests and peatlands: Effects on ecosystem carbon losses and soil carbon stabilization as black carbon

    NASA Astrophysics Data System (ADS)

    Turetsky, M. R.; Kane, E. S.; Benscoter, B.

    2011-12-01

    Climate change has increased both annual area burned and the severity of biomass combustion in some boreal regions. For example, there has been a four-fold increase in late season fires in boreal Alaska over the last decade relative to the previous 50 years. Such changes in the fire regime are expected to stimulate ecosystem carbon losses through fuel combustion, reduced primary production, and increased decomposition. However, biomass burning also will influence the accumulation of black carbon in soils, which could promote long-term soil carbon sequestration. Variations in slope and aspect regulate soil temperatures and drainage conditions, and affect the development of permafrost and thick peat layers. Wet soil conditions in peatlands and permafrost forests often inhibit combustion during wildfires, leading to strong positive correlations between pre- and post- fire organic soil thickness that persist through multiple fire cycles. However, burning can occur in poorly drained ecosystems through smouldering combustion, which has implications for emission ratios of CO2:CH4:CO as well as black carbon formation. Our studies of combustion severity and black carbon concentrations in boreal soils show a negative relationship between concentrations of black carbon and organic carbon in soils post-fire. Relative to well drained stands, poorly drained sites with thick peat layers (such as north-facing stands) had less severe burning and low concentrations of black carbon in mineral soils post-fire. Conversely, drier forests lost a greater proportion of their organic soils during combustion but retained larger black carbon stocks following burning. Overall, we have quantified greater black carbon concentrations in surface mineral soil horizons than in organic soil horizons. This is surprising given that wildfires typically do not consume the entire organic soil layer in boreal forests, and could be indicative of the vulnerability of black carbon formed in organic horizons

  6. Continuous flux of dissolved black carbon from a vanished tropical forest biome

    NASA Astrophysics Data System (ADS)

    Dittmar, T.; Rezende, C. E.; Manecki, M.; Niggemann, J.; Coelho Ovalle, A. R.; Bernardes, M. C.

    2012-04-01

    Humans have extensively used fire as a tool to shape Earth's vegetation. One of the biggest events in this context was the destruction of Brazilian's Atlantic forest, once among the largest tropical forest biomes on Earth. We estimate that the slash-and-burn practice produced 200 to 500 million tons of black carbon from the 1850' to 1973. The fate of this charred organic matter is unknown. Here we show continuous runoff of dissolved black carbon from the cleared forest biome, more than 35 years after the widespread burning of the forest ended. During the 11-year observation period (1997-2008) of this study, on average 0.04 to 0.08 tons of dissolved black carbon were annually exported per square kilometer land. We estimate an annual runoff of 48,000 to 97,000 tons dissolved black carbon from the former Atlantic forest biome. Dissolved black carbon was mobilized by water percolating through the soil during the rainy season. During base flow conditions, dissolved organic carbon (DOC) did not contain black carbon, whereas at peak flow up to 6% of DOC was combustion-derived. If runoff was the only removal mechanism of black carbon from soils, even the highly condensed and presumably refractory component of black carbon would have a half-life of only 440 to 2300 years in the soil. In areas with higher precipitation, stronger runoff and consequently a shorter half-life can be expected. In the deep ocean, dissolved black carbon is virtually inert on this time scale. The disappearance of the Atlantic forest provides a worst-case scenario for tropical forests worldwide, most of which are cleared at increasing rate. Because of the comparably fast mobilization of dissolved black carbon from soils and its resistivity in the deep ocean, an increase of black carbon production on land may alter the size of the global pool of >12 Pg carbon of thermally altered DOC in the ocean on the long term.

  7. Tungsten nitride nanocrystals on nitrogen-doped carbon black as efficient electrocatalysts for oxygen reduction reactions.

    PubMed

    Dong, Youzhen; Li, Jinghong

    2015-01-11

    The direct synthesis of tungsten nitride (WN) nanoparticles on nitrogen-doped carbon black (N-carbon black) was achieved through facile nucleation and growth of WN nanoparticles on simultaneously generated N-carbon black under ammonia annealing. As a noble-metal-free catalyst, the WN/N-carbon black hybrid exhibited excellent performance in ORR, coupled with superior methanol tolerance and long-term stability in comparison to commercial Pt/C catalysts, through an efficient four-electron-dominant ORR process. PMID:25413157

  8. Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Jacobson, Mark Z.

    2001-02-01

    Aerosols affect the Earth's temperature and climate by altering the radiative properties of the atmosphere. A large positive component of this radiative forcing from aerosols is due to black carbon-soot-that is released from the burning of fossil fuel and biomass, and, to a lesser extent, natural fires, but the exact forcing is affected by how black carbon is mixed with other aerosol constituents. From studies of aerosol radiative forcing, it is known that black carbon can exist in one of several possible mixing states; distinct from other aerosol particles (externally mixed) or incorporated within them (internally mixed), or a black-carbon core could be surrounded by a well mixed shell. But so far it has been assumed that aerosols exist predominantly as an external mixture. Here I simulate the evolution of the chemical composition of aerosols, finding that the mixing state and direct forcing of the black-carbon component approach those of an internal mixture, largely due to coagulation and growth of aerosol particles. This finding implies a higher positive forcing from black carbon than previously thought, suggesting that the warming effect from black carbon may nearly balance the net cooling effect of other anthropogenic aerosol constituents. The magnitude of the direct radiative forcing from black carbon itself exceeds that due to CH4, suggesting that black carbon may be the second most important component of global warming after CO2 in terms of direct forcing.

  9. Seasonal Variability of the Black Carbon Size Distribution in the Atmospheric Aerosol

    NASA Astrophysics Data System (ADS)

    Kozlov, V. S.; Shmargunov, V. P.; Panchenko, M. V.; Chernov, D. G.; Kozlov, A. S.; Malyshkin, S. B.

    2016-04-01

    Round-the-clock measurements of the black carbon size distribution in the submicron near-ground aerosol of Western Siberia performed in 2014 by the diffusion method developed by the authors are analyzed. It is revealed that the tendency for decreasing the volume median diameter and the amplitude of distribution of the black carbon is traced in the seasonal dynamics of the average monthly black carbon particle size distribution (approximated by a single-mode lognormal function) during winter-to-summer season transition. The shape of the black carbon size distributions is in agreement with measurements by other well-known methods in different geographic regions.

  10. Centennial black carbon turnover observed in a Russia steppe soil

    SciTech Connect

    Hammes, K.; Torn, M.S.; Lapenas, A.G.; Schmidt, M.W.I.

    2008-09-15

    Black carbon (BC), from incomplete combustion of fuels and biomass, has been considered highly recalcitrant and a substantial sink for carbon dioxide. Recent studies have shown that BC can be degraded in soils. We use two soils with very low spatial variability sampled 100 years apart in a Russian steppe preserve to generate the first whole-profile estimate of BC stocks and turnover in the field. Quantities of fire residues in soil changed significantly over a century. Black carbon stock was 2.5 kg m{sup -2}, or about 7-10% of total organic C in 1900. With cessation of biomass burning, BC stocks decreased 25% over a century, which translates into a centennial soil BC turnover (293 years best estimate; range 182-541 years), much faster than so-called inert or passive carbon in ecosystem models. The turnover time presented here is for loss by all processes, namely decomposition, leaching, and erosion, although the latter two were probably insignificant in this case. Notably, at both time points, the peak BC stock was below 30 cm, a depth interval, which is not typically accounted for. Also, the quality of the fire residues changed with time, as indicated by the use benzene poly carboxylic acids (BPCA) as molecular markers. The proportions of less-condensed (and thus more easily degradable) BC structures decreased, whereas the highly condensed (and more recalcitrant) BC structures survived unchanged over the 100-year period. Our results show that BC cannot be assumed chemically recalcitrant in all soils, and other explanations for very old soil carbon are needed.

  11. Black Carbon Emissions from Associated Natural Gas Flaring.

    PubMed

    Weyant, Cheryl L; Shepson, Paul B; Subramanian, R; Cambaliza, Maria O L; Heimburger, Alexie; McCabe, David; Baum, Ellen; Stirm, Brian H; Bond, Tami C

    2016-02-16

    Approximately 150 billion cubic meters (BCM) of natural gas is flared and vented in the world annually, emitting greenhouse gases and other pollutants with no energy benefit. About 7 BCM per year is flared in the United States, and half is from North Dakota alone. There are few emission measurements from associated gas flares and limited black carbon (BC) emission factors have been previously reported from the field. Emission plumes from 26 individual flares in the Bakken formation in North Dakota were sampled. Methane, carbon dioxide, and BC were measured simultaneously, allowing the calculation of BC mass emission factors using the carbon balance method. Particle optical absorption was measured using a three-wavelength particle soot absorption photometer (PSAP) and BC particle number and mass concentrations were measured with a single particle soot photometer. The BC emission factors varied over 2 orders of magnitude, with an average and uncertainty range of 0.14 ± 0.12 g/kg hydrocarbons in associated gas and a median of 0.07 g/kg which represents a lower bound on these measurements. An estimation of the BC emission factor derived from PSAP absorption provides an upper bound at 3.1 g/kg. These results are lower than previous estimations and laboratory measurements. The BC mass absorption cross section was 16 ± 12 m(2)/g BC at 530 nm. The average absorption Ångström exponent was 1.2 ± 0.8, suggesting that most of the light absorbing aerosol measured was black carbon and the contribution of light absorbing organic carbon was small. PMID:26764563

  12. Centennial black carbon turnover observed in a Russian steppe soil

    NASA Astrophysics Data System (ADS)

    Hammes, K.; Torn, M. S.; Lapenas, A. G.; Schmidt, M. W. I.

    2008-09-01

    Black carbon (BC), from incomplete combustion of fuels and biomass, has been considered highly recalcitrant and a substantial sink for carbon dioxide. Recent studies have shown that BC can be degraded in soils. We use two soils with very low spatial variability sampled 100 years apart in a Russian steppe preserve to generate the first whole-profile estimate of BC stocks and turnover in the field. Quantities of fire residues in soil changed significantly over a century. Black carbon stock was 2.5 kg m-2, or about 7 10% of total organic C in 1900. With cessation of biomass burning, BC stocks decreased 25% over a century, which translates into a centennial soil BC turnover (293 years best estimate; range 182 541 years), much faster than so-called inert or passive carbon in ecosystem models. The turnover time presented here is for loss by all processes, namely decomposition, leaching, and erosion, although the latter two were probably insignificant in this case. Notably, at both time points, the peak BC stock was below 30 cm, a depth interval, which is not typically accounted for. Also, the quality of the fire residues changed with time, as indicated by the use benzene polycarboxylic acids (BPCA) as molecular markers. The proportions of less-condensed (and thus more easily degradable) BC structures decreased, whereas the highly condensed (and more recalcitrant) BC structures survived unchanged over the 100-year period. Our results show that BC cannot be assumed chemically recalcitrant in all soils, and other explanations for very old soil carbon are needed.

  13. Seasonal features of black carbon measured at Syowa Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Hara, K.; Osada, K.; Yabuki, M.; Shiobara, M.; Yamanouchi, T.

    2015-12-01

    Black carbon (BC) is one of important aerosol constituents because the strong light absorption ability. Low concentrations of aerosols and BC let BC make insignificant contribution to aerosol radiative forcing in the Antarctica at the moment. Because of less or negligible source strength of BC in the Antarctic circle, BC can be used as a tracer of transport from the mid-latitudes. This study aims to understand seasonal feature, transport pathway, and origins of black carbon in the Antarctic coats. Black carbon measurement has been made using 7-wavelength aethalometer at Syowa Station, Antarctica since February, 2005. Mass BC concentrations were estimated from light attenuation by Weingartner's correction procedure (Weingartner et al., 2003) in this study. Detection limit was 0.2 - 0.4 ng/m3 in our measurement conditions (2-hour resolution and flow rate of ca. 10LPM). BC concentrations ranged from near detection limit to 55.7 ng/m3 at Syowa Station, Antarctica during the measurements. No trend has been observed since February, 2005. High BC concentrations were coincident with poleward flow from the mid-latitudes under the storm conditions by cyclone approach, whereas low BC concentrations were found in transport from coastal regions and the Antarctic continent. Considering that outflow from South America and Southern Africa affect remarkably air quality in the Southern Ocean of Atlantic and Indian Ocean sectors, BC at Syowa Station might be originated from biomass burning and human activity on South America and Southern Africa. Seasonal features of BC at Syowa Station shows maximum in September - October and lower in December - April. Spring maximum in September - October was obtained at the other Antarctic stations (Neumayer, Halley, South pole, and Ferraz). Although second maximum was found in January at the other stations, the maximum was not observed at Syowa Station.

  14. Barrow Black Carbon Source and Impact Study Final Campaign Report

    SciTech Connect

    Barrett, Tate

    2014-07-01

    The goal of the Barrow Black Carbon Source and Impact campaign was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement (ARM) Climate Research Facility site in Barrow, Alaska. The carbonaceous component was characterized by measuring the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the PM, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine PM fractions (PM2.5) and 49 coarse (PM10) PM fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the Barrow Black Carbon Source and Impact (BBCSI) study used standard Tisch “hi-vol” motors that have a known lifetime of approximately 1 month under constant use; this necessitated monthly maintenance, and it is suggested that, for future deployment in the Arctic, the motors be upgraded to industrial blowers. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric PM samples from Barrow, Alaska, from July 2012 to June 2013. Preliminary analysis of the OC and BC concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer. However, the annual OC concentrations had a very different seasonal pattern with the highest concentrations during the summer, lowest concentrations during the fall, and increased concentrations during the winter and spring (Figure 1).

  15. Multifunctional superhydrophobic polymer/carbon nanocomposites: graphene, carbon nanotubes, or carbon black?

    PubMed

    Asthana, Ashish; Maitra, Tanmoy; Büchel, Robert; Tiwari, Manish K; Poulikakos, Dimos

    2014-06-11

    Superhydrophobic surfaces resisting water penetration into their texture under dynamic impact conditions and offering simultaneously additional functionalities can find use in a multitude of applications. We present a facile, environmentally benign, and economical fabrication of highly electrically conductive, polymer-based superhydrophobic coatings, with impressive ability to resist dynamic water impalement through droplet impact. To impart electrical conductivity, the coatings were prepared by drop casting suspensions with loadings of different kinds of carbon nanoparticles, namely, carbon black (CB), carbon nanotubes (CNT), graphene nanoplatelets (GNP) and their combinations, in a fluoropolymer dispersion. At 50 wt % either CB or CNT, the nanocomposite coatings resisted impalement by water drops impacting at 3.7 m/s, the highest attainable speed in our setup. However, when tested with 5 vol % isopropyl alcohol-water mixture, i.e., a lower surface tension liquid posing a stiffer challenge with respect to impalement, only the CB coatings retained their impalement resistance behavior. GNP-based surfaces featured very high conductivity ∼1000 S/m, but the lowest resistance to water impalement. The optimal performance was obtained by combining the carbon fillers. Coatings containing CB:GNP:polymer = 1:1:2 showed both excellent impalement resistance (up to 3.5 m/s with 5 vol % IPA-water mixture drops) and electrical conductivity (∼1000 S/m). All coatings exhibited superhydrophobic and oleophilic behavior. To exemplify the additional benefit coming from this property, the CB and the optimal, combined CB/GNP coatings were used to separate mineral oil and water through filtration of their mixture. PMID:24846501

  16. Electrical conductivity and rheology of carbon black composites under elongation

    NASA Astrophysics Data System (ADS)

    Starý, Zdeněk

    2015-04-01

    Electrical properties of conductive polymer composites are governed by filler particle structures which are formed in the material during the mixing. Therefore, knowledge of the behavior of conductive particle structures under defined conditions of deformation is necessary to produce materials with balanced electrical and rheological properties. Whereas the electrical conductivity evolution under shear can be nowadays studied even with the commercial rheometers, the investigations under elongation were not performed up to now. In this work simultaneous electrical and rheological measurements in elongation on polystyrene/carbon black composites are introduced. Such kind of experiment can help in understanding the relationships between processing conditions and properties of conductive polymer composites.

  17. Black carbon concentrations and mixing state in the Finnish Arctic

    NASA Astrophysics Data System (ADS)

    Raatikainen, T.; Brus, D.; Hyvärinen, A.-P.; Svensson, J.; Asmi, E.; Lihavainen, H.

    2015-09-01

    Atmospheric aerosol composition was measured using a Single Particle Soot Photometer (SP2) in the Finnish Arctic during winter 2011-2012. The Sammaltunturi measurement site at the Pallas GAW (Global Atmosphere Watch) station receives air masses from different source regions including the Arctic Ocean and continental Europe. The SP2 provides detailed information about mass distributions and mixing state of refractory black carbon (rBC). The measurements showed widely varying rBC mass concentrations (0-120 ng m-3), which were related to varying contributions of different source regions and aerosol removal processes. The rBC mass was log-normally distributed showing a relatively constant rBC core mass mean diameter with an average of 194 nm (75-655 nm sizing range). On average, the number fraction of particles containing rBC was 0.24 (integrated over 350-450 nm particle diameter range) and the average particle diameter to rBC core volume equivalent diameter ratio was 2.0 (averaged over particles with 150-200 nm rBC core volume equivalent diameters). These average numbers mean that the observed rBC core mass mean diameter is similar to those of aged particles, but the observed particles seem to have unusually high particle to rBC core diameter ratios. Comparison of the measured rBC mass concentration with that of the optically detected equivalent black carbon (eBC) using an Aethalometer and a MAAP showed that eBC was larger by a factor of five. The difference could not be fully explained without assuming that only a part of the optically detected light absorbing material is refractory and absorbs light at the wavelength used by the SP2. Finally, climate implications of five different black carbon mixing state representations were compared using the Mie approximation and simple direct radiative forcing efficiency calculations. These calculations showed that the observed mixing state means significantly lower warming effect or even a net cooling effect when compared with

  18. Meta-Analysis of Cardiac Mortality in Three Cohorts of Carbon Black Production Workers

    PubMed Central

    Morfeld, Peter; Mundt, Kenneth A.; Dell, Linda D.; Sorahan, Tom; McCunney, Robert J.

    2016-01-01

    Epidemiological studies have demonstrated associations between airborne environmental particle exposure and cardiac disease and mortality; however, few have examined such effects from poorly soluble particles of low toxicity such as manufactured carbon black (CB) particles in the work place. We combined standardised mortality ratio (SMR) and Cox proportional hazards results from cohort studies of US, UK and German CB production workers. Under a common protocol, we analysed mortality from all causes, heart disease (HD), ischemic heart disease (IHD) and acute myocardial infarction (AMI). Fixed and random effects (RE) meta-regression models were fit for employment duration, and for overall cumulative and lugged quantitative CB exposure estimates. Full cohort meta-SMRs (RE) were 1.01 (95% confidence interval (CI) 0.79–1.29) for HD; 1.02 (95% CI 0.80–1.30) for IHD, and 1.08 (95% CI 0.74–1.59) for AMI mortality. For all three outcomes, meta-SMRs were heterogeneous, increased with time since first and time since last exposure, and peaked after 25–29 or 10–14 years, respectively. Meta-Cox coefficients showed no association with lugged duration of exposure. A small but imprecise increased AMI mortality risk was suggested for cumulative exposure (RE-hazards ratio (HR) = 1.10 per 100 mg/m3-years; 95% CI 0.92–1.31), but not for lugged exposures. Our results do not demonstrate that airborne CB exposure increases all-cause or cardiac disease mortality. PMID:27005647

  19. Carbon in black crusts from the Tower of London

    SciTech Connect

    Alessandra Bonazza; Peter Brimblecombe; Carlota M. Grossi; Cristina Sabbioni

    2007-06-15

    This paper investigates the origin, fluxes, and transformation of carbon compounds within black crusts on the stone walls of the Tower of London. The crusts were analyzed for elemental and organic carbon, including the water soluble fraction. The stratigraphy of the old, thicker crusts highlighted the presence of prismatic particles, spherical aluminosilicates and metals, and carbonaceous particles. These are indicative of wood, coal and oil combustion processes. Elemental carbon and low solubility compounds such as oxalates appeared to be conserved because of long residence times. Conversely, more soluble ions, like chloride and formate would be removed from the layers relatively quickly by rainfall. At higher organic carbon concentrations acetic acid may be produced within the crusts from biological transformations. Currently, traffic sources contribute to increasingly organic rich crusts. The deposition of elemental carbon to buildings darkens surfaces and has important aesthetic implications. The increased organic content may have further aesthetic consequence by changing the color of buildings to warmer tones, particularly browns and yellows. Management of historic buildings requires us to recognize the shift away from simple gypsum crusts to those richer in organic materials. 26 refs., 6 figs., 1 tab.

  20. Black-backed woodpecker habitat suitability mapping using conifer snag basal area estimated from airborne laser scanning

    NASA Astrophysics Data System (ADS)

    Casas Planes, Á.; Garcia, M.; Siegel, R.; Koltunov, A.; Ramirez, C.; Ustin, S.

    2015-12-01

    Occupancy and habitat suitability models for snag-dependent wildlife species are commonly defined as a function of snag basal area. Although critical for predicting or assessing habitat suitability, spatially distributed estimates of snag basal area are not generally available across landscapes at spatial scales relevant for conservation planning. This study evaluates the use of airborne laser scanning (ALS) to 1) identify individual conifer snags and map their basal area across a recently burned forest, and 2) map habitat suitability for a wildlife species known to be dependent on snag basal area, specifically the black-backed woodpecker (Picoides arcticus). This study focuses on the Rim Fire, a megafire that took place in 2013 in the Sierra Nevada Mountains of California, creating large patches of medium- and high-severity burned forest. We use forest inventory plots, single-tree ALS-derived metrics and Gaussian processes classification and regression to identify conifer snags and estimate their stem diameter and basal area. Then, we use the results to map habitat suitability for the black-backed woodpecker using thresholds for conifer basal area from a previously published habitat suitability model. Local maxima detection and watershed segmentation algorithms resulted in 75% detection of trees with stem diameter larger than 30 cm. Snags are identified with an overall accuracy of 91.8 % and conifer snags are identified with an overall accuracy of 84.8 %. Finally, Gaussian process regression reliably estimated stem diameter (R2 = 0.8) using height and crown area. This work provides a fast and efficient methodology to characterize the extent of a burned forest at the tree level and a critical tool for early wildlife assessment in post-fire forest management and biodiversity conservation.

  1. Effect of the Purple carbon black on the properties of NR/BR blend

    NASA Astrophysics Data System (ADS)

    Yanfang, Zhao; Dan, Liu; Shengbo, Lin; Binjian; Yinmei, Zhao; Shuangquan, Liao

    2014-08-01

    Purple black is light colored mineral filler mining in recent years in Hainan. The effect of the dosage of the purple carbon black and purple carbon black modificated by Si69 on the vulcanization characteristics, mechanical properties, thermal stability, the damping performance of NR/BR blend rubber were studied, and the blending adhesive tensile sections were analyzed by SEM. Research showed that, with the increasing dosage of the purple carbon black, vulcanization characteristics of NR/BR blend had a little change. Adding the purple carbon black into blending had a reinforcing effect. when the dosage of the purple carbon black was 20, the mechanical properties of blending adhesive was good; Coupling agent Si69 had a modification effect on the purple carbon black. With increasing dosage of Si69, performance of the rubber was improved initially and then decreased; when the mass fraction of Si69 was 8% of the dosage of the purple carbon black, rubber performance was optimal. Purple carbon black had no obvious effect on thermal stability of the rubber, but it improved the damping rubber temperature and damping factor.

  2. A photochemically resistant component in riverine dissolved black carbon

    NASA Astrophysics Data System (ADS)

    Dittmar, Thorsten; Riedel, Thomas; Niggemann, Jutta; Vähätalo, Anssi

    2015-04-01

    Rivers transport combustion-derived dissolved black carbon (DBC) to the oceans at an annual flux that is much higher than required to balance the oceanic inventory of DBC. To resolve this mismatch we studied the long-term stability of DBC in ten major world rivers that together account for approximately 1/3 of the global freshwater discharge to the oceans. Riverine DBC was remarkably resistant against microbial degradation, but decomposition of nearly all chromophoric dissolved organic matter under extensive irradiation with simulated sunlight removed almost 80% of DBC. Photochemically transformed DBC was further microbially decomposed by more than 10% in a subsequent one-year long bioassay. Based on these findings, on a global scale, the estimated riverine flux of microbially degraded and photo-resistant DBC is sufficient to replenish the oceans with DBC and likely contributes to the dissolved organic matter pool that persists in the oceans and sequesters carbon for centuries to millennia.

  3. Importance of unburned coal carbon, black carbon, and amorphous organic carbon to phenanthrene sorption in sediments.

    PubMed

    Cornelissen, Gerard; Gustafsson, Orjan

    2005-02-01

    The aim of this paper was to estimate the contribution to total phenanthrene sorption from unburned coal and black carbon (BC; soot and charcoal) in sediment. We determined sorption isotherms for five Argonne Premium Coal standards over a wide concentration interval (0.01-10 000 ng/L). The coals showed strong and nonlinear sorption (carbon-normalized K(F) = 5.41-5.96; nF = 0.68-0.82). Coal sorption appeared to become more nonlinear with increasing coal maturity. The coal's specific surface area appeared to influence K(F). On the basis of the current coal sorption observations combined with earlier petrographic analyses and BC sorption experiments, we calculated for one particular sediment that coal, BC, and "other" OC were all important to PHE sorption in the environmentally relevant nanogram per liter range. This indicates that it is important to consider strong sorption to coal in the risk assessment of coal-impacted geosorbents (e.g., river beds) where coal is mined/shipped and manufactured gas plant sites. PMID:15757337

  4. High Black Carbon (BC) Concentrations along Indian National Highways

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Singh, A. K.; Singh, R. P.

    2015-12-01

    Abstract:Black carbon (BC), the optically absorbing component of carbonaceous aerosol, has direct influence on radiation budget and global warming. Vehicular pollution is one of the main sources for poor air quality and also atmospheric pollution. The number of diesel vehicles has increased on the Indian National Highways during day and night; these vehicles are used for the transport of goods from one city to another city and also used for public transport. A smoke plume from the vehicles is a common feature on the highways. We have made measurements of BC mass concentrations along the Indian National Highways using a potable Aethalometer installed in a moving car. We have carried out measurements along Varanasi to Kanpur (NH-2), Varanasi to Durgapur (NH-2), Varanasi to Singrauli (SH-5A) and Varanasi to Ghazipur (NH-29). We have found high concentration of BC along highways, the average BC mass concentrations vary in the range 20 - 40 µg/m3 and found high BC mass concentrations up to 600 μg/m3. Along the highways high BC concentrations were characteristics of the presence of industrial area, power plants, brick kilns and slow or standing vehicles. The effect of increasing BC concentrations along the National Highways and its impact on the vegetation and human health will be presented. Key Words: Black Carbon; Aethalometer; mass concentration; Indian National Highways.

  5. In Brief: Reducing black carbon emissions could immediately reduce global temperature increases

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-03-01

    A new assessment by the United Nations Environment Programme (UNEP) shows that measures to reduce emissions of black carbon, or soot, which is produced through burning of wood and other biofuels as well as by some industrial processes, could improve public health and help to significantly reduce projected global temperature increases. The Integrated Assessment of Black Carbon and Tropospheric Ozone highlights how specific measures targeting black carbon and other emissions from fossil fuel extraction, residential wood-burning cooking, diesel vehicles, waste management, agriculture, and small industries could affect climate. Full implementation of a variety of measures to reduce black carbon and methane emissions could reduce future global warming by about 0.5°C, the assessment found. Reducing black carbon could have substantial benefits in the Arctic, the Himalayas, and other snow-covered regions because black carbon that settles on top of snow absorbs heat, speeding melting of snow and ice. Black carbon emission reductions would affect global temperatures more quickly than carbon dioxide emission reductions. Furthermore, reducing black carbon emissions would improve public health in the regions that emit large amounts of the harmful air pollutant.

  6. Changing Export of Dissolved Black Carbon from Arctic Rivers

    NASA Astrophysics Data System (ADS)

    Stubbins, A.; Spencer, R. G.; Mann, P. J.; Dittmar, T.; Niggemann, J.; Holmes, R. M.; McClelland, J. W.

    2014-12-01

    Arctic rivers carry black carbon (BC) from Arctic soils to the ocean, linking two of the largest carbon stores on Earth. Wildfires have charred biomass since land plants emerged. BC, a refractory component of char, has accumulated in soils. In the oceans, dissolved BC (DBC) has also accumulated. Here we use samples and data collected as part of the long-term, high temporal resolution Arctic Great Rivers Observatory to model export of DBC from the six largest Arctic Rivers. Scaling to the pan-Arctic catchment, we report that ~3 million tons of DBC are delivered to the Arctic Ocean each year, which is ~8% of dissolved organic carbon loads to the Arctic Ocean. We suggest the transfer of Arctic river DBC to areas of deep water formation is a major source of DBC to the deep ocean carbon store. As the Arctic warms, greater wildfire occurrence is expected to produce more BC and changing hydrology and permafrost thaw to promote DBC export. Thus, the transfer of BC from Arctic soils to the ocean is predicted to increase.

  7. Black Carbon in Sedimentary Organic Carbon in the Northeast Pacific using the Benzene Polycarboxylic Acid Method

    NASA Astrophysics Data System (ADS)

    Coppola, A. I.; Ziolkowski, L. A.; Druffel, E. R.

    2010-12-01

    Black carbon (BC) in the Northeast Pacific ultrafiltered dissolved organic matter (UDOM) was found to be surprisingly old with a 14C age of 18,000 +/-3,000 14C years (Ziolkowski and Druffel, 2010) using the Benzene Polycarboxylic Acid (BPCA) method, while BC in sedimentary organic carbon (SOC) was found to be 2,400-12,900 14C years older than non-BC SOC (Masiello and Druffel, 1998) with a different method. Using the dichromate-sulfuric acid oxidation method (Wolbach and Anders, 1989), Masiello and Druffel (1998) estimated that 12-31% of SOC in the Northeast Pacific and the Southern Ocean surface sediments was black carbon (BC). However, the dichromate-sulfuric acid oxidation may over-estimate the concentration of BC, because this method is more biased toward modern (char) material (Currie et al., 2002). Alternatively, the BPCA method isolates aromatic components of BC as benzene rings substituted with carboxylic acid groups, and provides structural information about the BC. Recent modifications to the BPCA method by Ziolkowski and Druffel (2009) involve few biases in quantifying BC in the continuum between char and soot in UDOM. Here we use the BPCA method to determine the concentrations and 14C values of BC in sediments from three sites in the Northeast Pacific Ocean. Constraining the difference between non-BC SOC and BC-SOC using the BPCA method allows for a more precise estimate of how much BC is present in the sediments and its 14C age. Presumably, the intermediate reservoir of BC is oceanic dissolved organic carbon (DOC) and is, in part, responsible for DOC’s great 14C age. These results can be utilized to better constrain the oceanic carbon budget as a possible sink of BC. References: Currie, L. A., Benner Jr., B. A., Kessler, J.D., et al (2002), A critical evaluation of interlaboratory data on total, elemental, and isotopic carbon in the carbonaceous particle reference material, nist srm 1649a, J. Res. Natl. Inst. Stand. Technol., 107, 279-298. Masiello, C

  8. Laboratory Evaluation of Selected Ways for Determining Black Carbon Source Emissions

    EPA Science Inventory

    A number of studies have been conducted which compare various methods for the determination of black carbon in the atmosphere. Relatively little attention has been paid, however, to similar measurements of black carbon from different types of emission sources. Of particular int...

  9. CONTINUOUS BLACK CARBON MEASUREMENTS INDOORS AND OUTDOORS AT AN OCCUPIED HOUSE FOR ONE YEAR

    EPA Science Inventory

    Black carbon is one of the components of particulate matter, and is of importance because the only known source of aerosol black carbon in the atmosphere is the combustion of carbonaceous fuels (Hansen, 1997). Polyaromatic hydrocarbons (PAH) formed in the combustion process ar...

  10. CARBON BLACK DISPERSION PRE-PLATING TECHNOLOGY FOR PRINTED WIRE BOARD MANUFACTURING

    EPA Science Inventory

    This project compared chemical use, waste generation, cost, and product quality between electroless copper and carbon-black-based preplating technologies at the printed wire board (PWB). manufacturing facility of McCurdy Circuits in Orange, CA. he carbon-black based preplating te...

  11. INDOOR-OUTDOOR RELATIONSHIPS OF PARTICLES, PAH, AND BLACK CARBON IN AN OCCUPIED TOWNHOUSE

    EPA Science Inventory

    Real-time instrumentation for measuring particles, PAH, and black carbon (soot) has been operated since May of 1998 in an occupied 3-story town house in Reston, VA. Indoor and outdoor concentrations have been measured every five minutes for the particles and black carbon and ev...

  12. Airborne radioactivity survey of the Miller Hill area, Carbon county, Wyoming

    USGS Publications Warehouse

    Meuschke, J.L.; Moxham, R.M.

    1953-01-01

    The accompanying map shows the results of an airborne radioactivity survey covering 65 square miles northwest of Miller Hill, Carbon county, Wyoming. The survey was made by the U.S. Geological Survey as part of a cooperative program with the U.S. Atomic Energy Commission. At 500 feet above the ground, the width of the zone from which anomalous radioactivity is measured varies with the intensity of radiation of the source and, for strong sources, the width would be as much as 1,400 feet. Quarter-mile spacing of the flight paths of the aircraft should be adequate to detect anomalies from strong sources of radioactivity. However, small areas of considerable radioactivity midway between flight paths may not be noted. The approximate location of each radioactivity anomaly is shown on the accompanying map. The plotted position of an anomaly may be in error by as much as a quarter of a mile owing to errors in the available base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The radioactivity anomalies shown on the accompanying map cannot be interpreted in terms of either the radioactive content or the extent of the source materials. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to uranium, or to thorium, or to a combination of uranium and thorium. The radioactivity that is recorded by airborne measurements at 500 feet above the ground can be caused by: 1. A moderately large area in which the rocks and soils are slightly more radioactive than the rocks and soils of the surrounding area. 2. A smaller area in which the rocks and soils are considerably more radioactive than rocks and soils in the surrounding area. 3. A very small area in which to rocks and soils are much more radioactive than the rocks and soils of the surrounding area. Any particular anomaly

  13. Photo-lability of deep ocean dissolved black carbon

    NASA Astrophysics Data System (ADS)

    Stubbins, A.; Niggemann, J.; Dittmar, T.

    2012-01-01

    Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzene polycarboxylic acid oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 d irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM C to 55 ± 15 nM C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 yr. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Photo-degradation is therefore posited as the primary sink for oceanic DBC and the survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but by the rate at which they are cycled through the surface ocean's photic zone.

  14. Characterization and Control of Airborne Particles Emitted During Production of Epoxy / Carbon Nanotube Nanocomposites

    PubMed Central

    Cena, Lorenzo G.; Peters, Thomas M.

    2016-01-01

    This work characterized airborne particles that were generated from the weighing of bulk, multi-wall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratiô1). The particles generated during sanding were predominately micron-sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 μm) tangled clusters. Respirable mass concentrations in the operator’s breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 μg/m3) compared to those with no LEV (GM = 2.68 μg/m3) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m3; p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec). PMID:21253981

  15. Characterization and control of airborne particles emitted during production of epoxy/carbon nanotube nanocomposites.

    PubMed

    Cena, Lorenzo G; Peters, Thomas M

    2011-02-01

    This work characterized airborne particles generated from the weighing of bulk, multiwall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratio ∼1). The particles generated during sanding were predominantly micron sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 μm) tangled clusters. Respirable mass concentrations in the operator's breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 μg/m(3) compared with those with no LEV (GM = 2.68 μg/m(3) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m(3); p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec). PMID:21253981

  16. Airborne sulfur trace species intercomparison campaign: Sulfur dioxide, dimethylsulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Hoell, James M., Jr.; Davis, Douglas D.

    1991-01-01

    Results from an airborne intercomparison of techniques to measure tropospheric levels of sulfur trace gases are presented. The intercomparison was part of the NASA Global Tropospheric Experiment (GTE) and was conducted during the summer of 1989. The intercomparisons were conducted on the Wallops Electra aircraft during flights from Wallops Island, Virginia, and Natal, Brazil. Sulfur measurements intercompared included sulfur dioxide (SO2), dimethylsulfide (DMS), hydrogen sulfide (H2S), carbon disulfide (CS2), and carbonyl sulfide (OCS). Measurement techniques ranged from filter collection systems with post-flight analyses to mass spectrometer and gas chromatograph systems employing various methods for measuring and identifying the sulfur gases during flight. Sampling schedules for the techniques ranged from integrated collections over periods as long as 50 minutes to one- to three-minute samples every ten or fifteen minutes. Several of the techniques provided measurements of more than one sulfur gas. Instruments employing different detection principles were involved in each of the sulfur intercomparisons. Also included in the intercomparison measurement scenario were a host of supporting measurements (i.e., ozone, nitrogen oxides, carbon monoxide, total sulfur, aerosols, etc.) for purposes of: (1) interpreting results (i.e., correlation of any noted instrument disagreement with the chemical composition of the measurement environment); and (2) providing supporting chemical data to meet CITE-3 science objectives of studying ozone/sulfur photochemistry, diurnal cycles, etc. The results of the intercomparison study are briefly discussed.

  17. Airborne Detection and Dynamic Modeling of Carbon Dioxide and Methane Plumes

    NASA Astrophysics Data System (ADS)

    Jacob, Jamey; Mitchell, Taylor; Whyte, Seabrook

    2015-11-01

    To facilitate safe storage of greenhouse gases such as CO2 and CH4, airborne monitoring is investigated. Conventional soil gas monitoring has difficulty in distinguishing gas flux signals from leakage with those associated with meteorologically driven changes. A low-cost, lightweight sensor system has been developed and implemented onboard a small unmanned aircraft that measures gas concentration and is combined with other atmospheric diagnostics, including thermodynamic data and velocity from hot-wire and multi-hole probes. To characterize the system behavior and verify its effectiveness, field tests have been conducted over controlled rangeland burns and over simulated leaks. In the former case, since fire produces carbon dioxide over a large area, this was an opportunity to test in an environment that while only vaguely similar to a carbon sequestration leak source, also exhibits interesting plume behavior. In the simulated field tests, compressed gas tanks are used to mimic leaks and generate gaseous plumes. Since the sensor response time is a function of vehicle airspeed, dynamic calibration models are required to determine accurate location of gas concentration in (x , y , z , t) . Results are compared with simulations using combined flight and atmospheric dynamic models. Supported by Department of Energy Award DE-FE0012173.

  18. Making Carbon Emissions Remotely Sensible: Flux Observations of Carbon from an Airborne Laboratory (FOCAL), its Near-Surface Survey of Carbon Gases and Isotopologues on Alaska's North Slope

    NASA Astrophysics Data System (ADS)

    Dobosy, R.; Dumas, E. J.; Sayres, D. S.; Healy, C. E.; Munster, J. B.; Baker, B.; Anderson, J. G.

    2014-12-01

    Detailed process-oriented study of the mechanisms of conversion in the Arctic of fossil carbon to atmospheric gas is progressing, but necessarily limited to a few point locations and requiring detailed subsurface measurements inaccessible to remote sensing. Airborne measurements of concentration, transport and flux of these carbon gases at sufficiently low altitude to reflect surface variations can tie such local measurements to remotely observable features of the landscape. Carbon dioxide and water vapor have been observable for over 20 years from low-altitude small aircraft in the Arctic and elsewhere. Methane has been more difficult, requiring large powerful aircraft or limited flask samples. Recent developments in spectroscopy, however, have reduced the power and weight required to measure methane at rates suitable for eddy-covariance flux estimates. The Flux Observations of Carbon from an Airborne Laboratory (FOCAL) takes advantage of Integrated Cavity-Output Spectroscopy (ICOS) to measure CH4, CO2, and water vapor in a new airborne system. The system, moreover, measures these gases' stable isotopologues every two seconds or faster helping to separate thermogenic from biogenic emissions. Paired with the Best Airborne Turbulence (BAT) probe developed for small aircraft by NOAA's Air Resources Laboratory and a light twin-engine aircraft adapted by Aurora Flight Sciences Inc., the FOCAL measures at 6 m spacing, covering 100 km in less than 30 minutes. It flies between 10 m and 50 m above ground interspersed with profiles to the top of the boundary layer and beyond. This presentation gives an overview of the magnitude and variation in fluxes and concentrations of CH4, CO2, and H2O with space, time, and time of day in a spatially extensive survey, more than 7500 km total in 15 flights over roughly a 100 km square during the month of August 2013. An extensive data set such as this at low altitude with high-rate sampling addresses features that repeat on 1 km scale

  19. Influence of carbon black and indium tin oxide absorber particles on laser transmission welding

    NASA Astrophysics Data System (ADS)

    Aden, Mirko; Mamuschkin, Viktor; Olowinsky, Alexander

    2015-06-01

    For laser transmission welding of polypropylene carbon black and indium tin oxide (ITO) are used as absorber particles. Additionally, the colorant titanium dioxide is mixed to the absorbing part, while the transparent part is kept in natural state. The absorption coefficients of ITO and carbon black particles are obtained, as well as the scattering properties of polypropylene loaded with titanium dioxide (TiO2). At similar concentrations the absorption coefficient of ITO is an order of magnitude smaller than that of carbon black. Simulations of radiation propagation show that the penetration depth of laser light is smaller for carbon black. Therefore, the density of the released heat is higher. Adding TiO2 changes the distribution of heat in case of ITO, whereas for carbon black the effect is negligible. Thermal simulations reveal the influence of the two absorbers and TiO2 on the heat affected zone. The results of the thermal simulations are compared to tensile test results.

  20. Soft X-Ray Absorption Spectroscopy of High-Abrasion-Furnace Carbon Black

    NASA Astrophysics Data System (ADS)

    Muramatsu, Yasuji; Harada, Ryusuke; Gullikson, Eric M.

    2007-02-01

    The soft x-ray absorption spectra of high-abrasion-furnace carbon black were measured to obtain local-structure/chemical-states information of the primary particles and/or crystallites. The soft x-ray absorption spectral features of carbon black represent broader π* and σ* peak structures compared to highly oriented pyrolytic graphite (HOPG). The subtracted spectra between the carbon black and HOPG, (carbon black) — (HOPG), show double-peak structures on both sides of the π* peak. The lower-energy peak, denoted as the "pre-peak", in the subtracted spectra and the π*/σ* peak intensity ratio in the absorption spectra clearly depend on the specific surface area by nitrogen adsorption (NSA). Therefore, it is concluded that the pre-peak intensity and the π*/σ* ratio reflect the local graphitic structure of carbon black.

  1. Light Absorption in Arctic Sea Ice - Black Carbon vs Chlorophyll

    NASA Astrophysics Data System (ADS)

    Ogunro, O. O.; Wingenter, O. W.; Elliott, S.; Hunke, E. C.; Flanner, M.; Wang, H.; Dubey, M. K.; Jeffery, N.

    2015-12-01

    The fingerprint of climate change is more obvious in the Arctic than any other place on Earth. This is not only because the surface temperature there has increased at twice the rate of global mean temperature but also because Arctic sea ice extent has reached a record low of 49% reduction relative to the 1979-2000 climatology. Radiation absorption through black carbon (BC) deposited on Arctic snow and sea ice surface is one of the major hypothesized contributors to the decline. However, we note that chlorophyll-a absorption owing to increasing biology activity in this region could be a major competitor during boreal spring. Modeling of sea-ice physical and biological processes together with experiments and field observations promise rapid progress in the quality of Arctic ice predictions. Here we develop a dynamic ice system module to investigate discrete absorption of both BC and chlorophyll in the Arctic, using BC deposition fields from version 5 of Community Atmosphere Model (CAM5) and vertically distributed layers of chlorophyll concentrations from Sea Ice Model (CICE). To this point, our black carbon mixing ratios compare well with available in situ data. Both results are in the same order of magnitude. Estimates from our calculations show that sea ice and snow around the Canadian Arctic Archipelago and Baffin Bay has the least black carbon absorption while values at the ice-ocean perimeter in the region of the Barents Sea peak significantly. With regard to pigment concentrations, high amounts of chlorophyll are produced in Arctic sea ice by the bottom microbial community, and also within the columnar pack wherever substantial biological activity takes place in the presence of moderate light. We show that the percentage of photons absorbed by chlorophyll in the spring is comparable to the amount attributed to BC, especially in areas where the total deposition rates are decreasing with time on interannual timescale. We expect a continuous increase in

  2. Black Carbon Deposition on Glaciers and in the Seasonal Snowpack in Western Washington's Mountainous Regions

    NASA Astrophysics Data System (ADS)

    Delaney, I.; Kaspari, S.; Larrabee, M.

    2012-12-01

    Black carbon deposition on snow and ice darkens the surface of glaciers and snowpack, reducing albedo. Radiation absorbed by black carbon in snow can accelerate snowmelt and change the timing of runoff. This is particularly important in Washington State, as glaciers and seasonal snowpack have shrunk considerably in recent years and are integral to the region's water resources. However, little data exists regarding the concentration of black carbon in Washington snow, which is necessary to determine if enough black carbon is present to substantially accelerate snowmelt. From the winter through the summer of 2012, we collected snow samples from the snow surface, snow pits and snow cores (< 5 m depth, in many cases capturing the entire annual snowpack). Study sites include the Nisqually and Emmons glaciers on Mt. Rainier, Blewett Pass in the central Cascades, N. Klawatti, Noisy and Sandalee glaciers in the North Cascades and Blue Glacier on Mt. Olympus. Samples were analyzed for black carbon using a Single Particle Soot Photometer (SP2), and select samples were also analyzed for black carbon using a Sunset Lab OC-EC Aerosol Analyzer to compare with the SP2 method. We use the resultant data set to examine how snow accumulation, dry deposition, and proximity to emission sources (such as the Puget Sound metropolitan area) affect black carbon concentration in snow and ice. The results of this research provide insight in to 1) regional scale variation in black carbon deposition, 2) temporal trends in black carbon deposition, and 3) the persistence of black carbon in the snowpack throughout the season.

  3. Improving estimation of tree carbon stocks by harvesting aboveground woody biomass within airborne LiDAR flight areas

    NASA Astrophysics Data System (ADS)

    Colgan, M.; Asner, G. P.; Swemmer, A. M.

    2011-12-01

    The accurate estimation of carbon stored in a tree is essential to accounting for the carbon emissions due to deforestation and degradation. Airborne LiDAR (Light Detection and Ranging) has been successful in estimating aboveground carbon density (ACD) by correlating airborne metrics, such as canopy height, to field-estimated biomass. This latter step is reliant on field allometry which is applied to forest inventory quantities, such as stem diameter and height, to predict the biomass of a given tree stem. Constructing such allometry is expensive, time consuming, and requires destructive sampling. Consequently, the sample sizes used to construct such allometry are often small, and the largest tree sampled is often much smaller than the largest in the forest population. The uncertainty resulting from these sampling errors can lead to severe biases when the allometry is applied to stems larger than those harvested to construct the allometry, which is then subsequently propagated to airborne ACD estimates. The Kruger National Park (KNP) mission of maintaining biodiversity coincides with preserving ecosystem carbon stocks. However, one hurdle to accurately quantifying carbon density in savannas is that small stems are typically harvested to construct woody biomass allometry, yet they are not representative of Kruger's distribution of biomass. Consequently, these equations inadequately capture large tree variation in sapwood/hardwood composition, root/shoot/leaf allocation, branch fall, and stem rot. This study eliminates the "middleman" of field allometry by directly measuring, or harvesting, tree biomass within the extent of airborne LiDAR. This enables comparisons of field and airborne ACD estimates, and also enables creation of new airborne algorithms to estimate biomass at the scale of individual trees. A field campaign was conducted at Pompey Silica Mine 5km outside Kruger National Park, South Africa, in Mar-Aug 2010 to harvest and weigh tree mass. Since

  4. Electrical properties of foamed polypropylene/carbon black composites

    NASA Astrophysics Data System (ADS)

    Iliev, M.; Kotzev, G.; Vulchev, V.

    2016-02-01

    Polypropylene composites containing carbon black fillers were produced by vibration assisted extrusion process. Solid (unfoamed) composite samples were molded by conventional injection molding method, while structural foams were molded by a low pressure process. The foamed samples were evidenced to have a solid skin-foamed core structure which main parameters were found to depend on the quantity of material injected in the mold. The average bubbles' sizes and their distribution were investigated by scanning electron microscopy. It is established that the conductivity of the foamed samples gradually decreases when reducing the sample density. Nevertheless, the conductivity is found to be lower than the conductivity of the unfoamed samples both being of the same order. The flexural properties of the composites were studied and the results were discussed in the context of the structure parameters of the foamed samples.

  5. Optical Properties of Small Ice Crystals with Black Carbon Inclusions

    NASA Astrophysics Data System (ADS)

    Yang, X.; Geier, M.; Arienti, M.

    2013-12-01

    The optical properties of ice crystals play a fundamental role in modeling atmospheric radiation and hydrological cycle, which are critical in monitoring climate change. While Black Carbon (BC) is recognized as the dominant absorber with positive radiative forcing (warming) (Ramanathan & Carmichael, 2008), in-situ observations (Cappa, et al, 2012) indicate that the characterization of the mixing state of BC with ice crystals and other non-BC particles in global climate models (Ghan & Schwartz, 2007) needs further investigation. The limitation in the available mixing models is due to the drastically different absorbing properties of BC compared to other aerosols. We explore the scattering properties of ice crystals (in shapes commonly found in cirrus clouds and contrails - Yang, et al. 2012) with the inclusion of BC particles. The Discrete Dipole Approximation (DDA) (Yurkin & Hoekstra, 2011) is utilized to directly calculate the optical properties of the crystals with multiple BC inclusions, modeled as a distribution of spheres. The results are then compared with the most popular models of internal and external mixing (Liou, et al. 2011). The DDA calculations are carried out over a broad range of BC particle sizes and volume fractions within the crystal at the 532 nm wavelength and for ice crystals smaller than 50 μm. The computationally intensive database generated in this study is critical for understanding the effect of different types of BC inclusions on the atmosphere radiative forcing. Examples will be discussed to illustrate the modification of BC optical properties by encapsulation in ice crystals and how the parameterization of the BC mixing state in global climate models can be improved. Acknowledgements Support by Sandia National Laboratories' LDRD (Laboratory Directed Research and Development) is gratefully acknowledged. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of

  6. Black carbon aerosol-induced Northern Hemisphere tropical expansion

    NASA Astrophysics Data System (ADS)

    Kovilakam, Mahesh; Mahajan, Salil

    2015-06-01

    Global climate models (GCMs) underestimate the observed trend in tropical expansion. Recent studies partly attribute it to black carbon (BC) aerosols, which are poorly represented in GCMs. We conduct a suite of idealized experiments with the Community Atmosphere Model version 4 coupled to a slab ocean model forced with increasing BC concentrations covering a large swath of the estimated range of current BC radiative forcing while maintaining their spatial distribution. The Northern Hemisphere (NH) tropics expand poleward nearly linearly as BC radiative forcing increases (0.7° W-1 m2), indicating that a realistic representation of BC could reduce GCM biases. We find support for the mechanism where BC-induced midlatitude tropospheric heating shifts the maximum meridional tropospheric temperature gradient poleward resulting in tropical expansion. We also find that the NH poleward tropical edge is nearly linearly correlated with the location of the Intertropical Convergence Zone, which shifts northward in response to increasing BC.

  7. Enhanced haze pollution by black carbon in megacities in China

    NASA Astrophysics Data System (ADS)

    Ding, A. J.; Huang, X.; Nie, W.; Sun, J. N.; Kerminen, V.-M.; Petäjä, T.; Su, H.; Cheng, Y. F.; Yang, X.-Q.; Wang, M. H.; Chi, X. G.; Wang, J. P.; Virkkula, A.; Guo, W. D.; Yuan, J.; Wang, S. Y.; Zhang, R. J.; Wu, Y. F.; Song, Y.; Zhu, T.; Zilitinkevich, S.; Kulmala, M.; Fu, C. B.

    2016-03-01

    Aerosol-planetary boundary layer (PBL) interactions have been found to enhance air pollution in megacities in China. We show that black carbon (BC) aerosols play the key role in modifying the PBL meteorology and hence enhancing the haze pollution. With model simulations and data analysis from various field observations in December 2013, we demonstrate that BC induces heating in the PBL, particularly in the upper PBL, and the resulting decreased surface heat flux substantially depresses the development of PBL and consequently enhances the occurrences of extreme haze pollution episodes. We define this process as the "dome effect" of BC and suggest an urgent need for reducing BC emissions as an efficient way to mitigate the extreme haze pollution in megacities of China.

  8. Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty

    NASA Technical Reports Server (NTRS)

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kinne, S.; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2013-01-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  9. Comparative studies of industrial grade carbon black powders

    NASA Astrophysics Data System (ADS)

    Chawla, Komal; Chauhan, Alok P. S.

    2016-05-01

    Comparative studies of two dissimilar industrial grade Carbon Black (CB) powders (N375 and N405) were conducted. The structure, surface area and particle size are the three important characteristics of CB powder that determine their processability and application as filler in preparing rubber compounds. The powders were characterized for their structure using dibutyl phthalate absorption (DBPA), particle size via laser particle size analyzer and surface area by nitrogen adsorption method. The structural characterization showed that N405 had lower DBPA in comparison to N375, confirming low structure of N405 grade CB powder. It was observed from the particle size analysis that N375 was coarser than N405 grade CB. The total surface area values were determined by the BET method based on the cross sectional area of the nitrogen molecule. N375, a coarse grade CB powder with high structure, depicted less surface area as compared to N405.

  10. Potentiometric sensors with carbon black supporting platinum nanoparticles.

    PubMed

    Paczosa-Bator, Beata; Cabaj, Leszek; Piech, Robert; Skupień, Krzysztof

    2013-11-01

    For the first time, a single-piece, all-solid-state ion-selective electrode was fabricated with carbon black supporting platinum nanoparticles (PtNPs-CB) and a polymeric membrane. The PtNPs-CB, as an intermediate layer, was drop-casted directly on the solid substrate, and then an ionophore-doped solvent polymeric membrane was added in order to form a sensor. The performance of the newly developed electrodes was evaluated on the basis of potassium and nitrate ions. The stability of the electrical potential for the electrodes was examined by performing current-reversal chronopotentiometry, and the influence of the interfacial water film was assessed by the potentiometric aqueous-layer test. Fabricated potassium- and nitrate-selective electrodes displayed a Nernstian slope and several outstanding properties such as high long-term potential stability, potential repeatability, and reproducibility. PMID:24094044

  11. Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty

    SciTech Connect

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Bian, Huisheng; Bellouin, N.; Diehl, T.; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kinne, Stefan; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, Xiaohong; Penner, Joyce E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, Kai

    2013-03-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  12. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Carbon black, 4- substituted] phenyl... Significant New Uses for Specific Chemical Substances § 721.10075 Carbon black, 4- substituted] phenyl...) The chemical substance identified generically as carbon black, 4- substituted] phenyl-modified,...

  13. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Carbon black, 4- substituted] phenyl... Significant New Uses for Specific Chemical Substances § 721.10075 Carbon black, 4- substituted] phenyl...) The chemical substance identified generically as carbon black, 4- substituted] phenyl-modified,...

  14. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Carbon black, 4- substituted] phenyl... Significant New Uses for Specific Chemical Substances § 721.10075 Carbon black, 4- substituted] phenyl...) The chemical substance identified generically as carbon black, 4- substituted] phenyl-modified,...

  15. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Carbon black, 4- substituted] phenyl... Significant New Uses for Specific Chemical Substances § 721.10075 Carbon black, 4- substituted] phenyl...) The chemical substance identified generically as carbon black, 4- substituted] phenyl-modified,...

  16. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carbon black, 4- substituted] phenyl... Significant New Uses for Specific Chemical Substances § 721.10075 Carbon black, 4- substituted] phenyl...) The chemical substance identified generically as carbon black, 4- substituted] phenyl-modified,...

  17. Continuous flux of dissolved black carbon from a vanished tropical forest biome

    NASA Astrophysics Data System (ADS)

    Dittmar, Thorsten; de Rezende, Carlos Eduardo; Manecki, Marcus; Niggemann, Jutta; Coelho Ovalle, Alvaro Ramon; Stubbins, Aron; Bernardes, Marcelo Correa

    2012-09-01

    Humans have used fire extensively as a tool to shape Earth's vegetation. The slash-and-burn destruction of Brazil's Atlantic forest, which once covered over 1.3millionkm2 of present-day Brazil and was one of the largest tropical forest biomes on Earth, is a prime example. Here, we estimate the amount of black carbon generated by the burning of the Atlantic forest, using historical records of land cover, satellite data and black carbon conversion ratios. We estimate that before 1973, destruction of the Atlantic forest generated 200-500 million tons of black carbon. We then estimate the amount of black carbon exported from this relict forest between 1997 and 2008, using measurements of polycyclic aromatic black carbon collected from a large river draining the region, and a continuous record of river discharge. We show that dissolved black carbon (DBC) continues to be mobilized from the watershed each year in the rainy season, despite the fact that widespread forest burning ceased in 1973. We estimate that the river exports 2,700 tons of DBC to the ocean each year. Scaling our findings up, we estimate that 50,000-70,000 tons of DBC are exported from the former forest each year. We suggest that an increase in black carbon production on land could increase the size of the refractory pool of dissolved organic carbon in the deep ocean.

  18. Modeling plumes containing black-carbon from Siberian sources to the Arctic

    NASA Astrophysics Data System (ADS)

    Raut, J.; Fast, J. D.; Law, K.; Weinzierl, B.; Rose, M.; Kim, J.; Thomas, J. L.; Marelle, L.; Roiger, A.; Schlager, H.; Reiter, A.; Quennehen, B.; Ma, P.; Singh, B.; Rasch, P. J.

    2013-12-01

    There are currently large uncertainties in global climate model predictions of black carbon (BC) in the Arctic. These differences are in part due to uncertainties in anthropogenic and biomass burning emissions, errors arising from model parameterizations, and inadequate spatial resolution in large scale models. In addition to the contribution to aerosol radiative forcing, black carbon deposited on snow alters its albedo and consequently the rate of melting. Our study presents the main pollution transport pathways from Siberia to the Arctic and how they impact the Arctic air composition in summer and spring. We focus on two periods (summer 2012 and spring 2008) when field campaigns took place in the Arctic. As part of the Arctic Climate Change, Economy and Society (ACCESS) project, an aircraft campaign was conducted in July 2012 in Andøya, Norway. The main focus of the campaign was to investigate the role of current and future anthropogenic activities in and near the Arctic on regional air pollution and to analyze potential connections to Arctic climate. To put the emerging local pollution within a broader context, biomass burning plumes containing black carbon imported from Siberian wildfires were sampled during the campaign. Two flights north of Norway into the Arctic, with a refueling stop in Spitsbergen focused specifically on biomass burning pollution transported across the North Pole from Siberia. To simulate the emission, transport, and fate of black carbon, we use a regional chemical transport model, the Weather Research and Forecasting model with chemistry (WRF-Chem), with a model domain that encompasses most of the northern hemisphere. The model is able to represent the most intense plumes sampled during the flights in the North of Spitsbergen, with ~120 ppb CO enhancement. The simulations show a clear connection of these plumes to fires in Siberia and Central Russia and are complemented by a more detailed comparison to airborne observations and satellite

  19. ARM-ACME V: ARM Airborne Carbon Measurements V on the North Slope of Alaska Science and Implementation Plan

    SciTech Connect

    Biraud, S

    2015-05-01

    Atmospheric temperatures are warming faster in the Arctic than predicted by climate models. The impact of this warming on permafrost degradation is not well understood, but it is projected to increase carbon decomposition and greenhouse gas production (CO₂ and/or CH₄) by arctic ecosystems. Airborne observations of atmospheric trace gases, aerosols, and cloud properties at the North Slope of Alaska are improving our understanding of global climate, with the goal of reducing the uncertainty in global and regional climate simulations and projections.

  20. Observation of black carbon, ozone and carbon monoxide in the Kali Gandaki Valley Nepal

    NASA Astrophysics Data System (ADS)

    Dhungel, S.; Panday, A. K.; Kathayat, B.

    2014-12-01

    The increased melting of snow and ice in the arctic and the Himalaya is a growing concern for all of the earth's population. Deposition of black carbon (BC) on the snow and ice surface accelerates melting by absorbing the radiative energy and directly transferring all that energy onto the underlying surface. During pre-monsoon season, satellite images show a thick layer of haze covering the Indo-Gangetic plain (IGP) and the Himalayan foothills. Sub-micron particles are transported to the Himalaya from the IGP predominantly driven by the thermal valley wind system. The Himalayas consist of some of the tallest mountain ranges in the world, over 8000m tall that reach the stratosphere. The Kali Gandaki Valley in Nepal is one of the deepest gorges in the world, and has some of the highest up-valley winds in the world. It is also one of the most open connecting points for air from IGP to reach the Tibetan Plateau. In 2010 the University of Virginia, in collaboration with ICIMOD and Nepal Wireless, established an atmospheric research station in Jomsom, Nepal (28.78N, 83.42E, 2900 m.a.s.l.) half-way along the Kali Gandaki valley. The station is equipped to measure black carbon (BC), carbon monoxide (CO), and ozone concentrations. It also has an automated weather station, a filter sampler, and a NASA Aeronet Sunphotometer. Here we present our observations of black carbon, ozone, carbon monoxide at Jomsom to show the diurnal and seasonal variability of the pollutants. The results show diurnal patterns in the concentration of these pollutants and also episodes of high pollutant transport along the valley. These transport episodes are more common during the pre-monsoon season which indicates that deep mountain valleys like the Kali Gandaki valley facilitate the transport of pollutants and thus promote snow and glacial melting.

  1. A Nadir-adjusted Airborne Multi Spectral Imaging System (NAMSIS) for high-resolution remote sensing of carbon fluxes

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Scott, S.; Rahman, A. F.

    2012-12-01

    Satellite remote sensing is widely used in vegetation monitoring, water stress detection and carbon cycle modeling. However, image pixels from high temporal resolution satellite sensors (such as MODIS) have coarse spatial resolution, much larger than the canopies they are supposed to characterize. An alternative solution for on-demand high spatial resolution remote sensing is sensors onboard low-flying aircrafts. Airborne remote sensing has been traditionally used in crop management studies. In this presentation we demonstrate the application of a relatively low-cost airborne sensor system with customized spectral band combinations for studying forest carbon fluxes. Our team has developed an Inertia Measurement Unit (IMU) controlled automated system to detach aircraft movements (pitch and roll) and engine vibration from the six-band programmable imager, in order to maintain the sensor at nadir view at all times during the flight. Flight lines are configured by a GPS-controleld system to simulate MODIS pixels. A feature-based algorithm is used to automatically generate a mosaic of individual images along the flight lines. This algorithm eliminates the need to mosiac and georeference images manually. An empirical line method is used to calculate reflectance from the raw data. Images from this airborne system produce reflectance values that are comparable with MODIS reflectance product. These high spatial resolution (~0.5 m) images deliver detailed information about tree species and phenological conditions within each MODIS pixel, and thus permit a high resolution spatio-temporal assessment of forest carbon fluxes.

  2. Carbon black dispersion pre-plating technology for printed wire board manufacturing. Final technology evaluation report

    SciTech Connect

    Folsom, D.W.; Gavaskar, A.R.; Jones, J.A.; Olfenbuttel, R.F.

    1993-10-01

    The project compared chemical use, waste generation, cost, and product quality between electroless copper and carbon-black-based preplating technologies at the printed wire board (PWB) manufacturing facility of McCurdy Circuits in Orange, CA. The carbon-black based preplating technology evaluated is used as an alternative process for electroless copper (EC) plating of through-holes before electrolytic copper plating. The specific process used at McCurdy is the BlackHole (BH) technology process, which uses a dispersion of carbon black in an aqueous solution to provide a conductive surface for subsequent electrolytic copper plating. The carbon-black dispersion technology provided effective waste reduction and long-term cost savings. The economic analysis determined that the new process was cost efficient because chemical use was reduced and the process proved more efficient; the payback period was less than 4 yrs.

  3. First Airborne Lidar Measurements of Methane and Carbon Dioxide Applying the MERLIN Demonstrator CHARM-F

    NASA Astrophysics Data System (ADS)

    Amediek, Axel; Büdenbender, Christian; Ehret, Gerhard; Fix, Andreas; Gerbig, Christoph; Kiemle, Chritstoph; Quatrevalet, Mathieu; Wirth, Martin

    2016-04-01

    CHARM-F is the new airborne four-wavelengths lidar for simultaneous soundings of atmospheric CO2 and CH4. Due to its high technological conformity it is also a demonstrator for MERLIN, the French-German satellite mission providing a methane lidar. MERLIN's Preliminary Design Review was successfully passed recently. The launch is planned for 2020. First CHARM-F measurements were performed in Spring 2015 onboard the German research aircraft HALO. The aircraft's maximum flight altitude of 15 km and special features of the lidar, such as a relatively large laser ground spot, result in data similar to those obtained by a spaceborne system. The CHARM-F and MERLIN lidars are designed in the IPDA (integrated path differential absorption) configuration using short double pulses, which gives column averaged gas mixing ratios between the system and ground. The successfully completed CHARM-F flight measurements provide a valuable dataset, which supports the retrieval algorithm development for MERLIN notably. Furthermore, the dataset allows detailed analyses of measurement sensitivities, general studies on the IPDA principle and on system design questions. These activities are supported by another instrument onboard the aircraft during the flight campaign: a cavity ring down spectrometer, providing in-situ data of carbon dioxide, methane and water vapor with high accuracy and precision, which is ideal for validation purposes of the aircraft lidar. For the near future, detailed characterizations of CHARM-F are planned, further support of the MERLIN design, as well as the scientific aircraft campaign CoMet.

  4. Methods to Parameterize Brown Carbon, Distinguish Brown Carbon Absorption From Enhanced Black Carbon Absorption, and Assess the Stability of Brown Carbon to Photochemical Aging

    NASA Astrophysics Data System (ADS)

    Murphy, S. M.; Pokhrel, R. P.; Beamesderfer, E.; Wagner, N. L.; Langridge, J.; Lack, D.

    2015-12-01

    We present results obtained during the Fire Lab at Missoula Experiment-4 (FLAME-4) with a combination of multi-wavelength photoacoustic and cavity ringdown spectrometers. It will be shown that the single scattering albedo and Angstrom exponent of biomass burning emissions can be better parameterized by the organic carbon to black carbon ratio than by the modified combustion efficiency. Two different methods to distinguish the contribution to aerosol absorption from brown carbon versus black carbon and enhanced black carbon absorption will be presented. One method is based on extending the absorption seen at 660 nm with an assumed Angstrom exponent while the other assumes a similar absorption enhancement (determined via thermal denuder) of black carbon at 660 and 405 nm. Potential errors and advantages of both methods will be discussed. Finally, chamber experiments that show degradation of brown carbon by photochemical oxidation will be presented along with a number of methods by which to assess the amount of brown carbon that is degraded.

  5. Calculations of Solar Shortwave Heating Rates due to Black Carbon and Ozone Absorption Using in Situ Measurements

    NASA Technical Reports Server (NTRS)

    Gao, R. S.; Hall, S. R.; Swartz, W. H.; Spackman, J. R.; Watts, L. A.; Fahey, D. W.; Aikin, K. C.; Shetter, R. E.; Bui, T. P.

    2008-01-01

    Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.

  6. Impacts of black carbon mixing state on black carbon nucleation scavenging: Insights from a particle-resolved model

    NASA Astrophysics Data System (ADS)

    Ching, J.; Riemer, N.; West, M.

    2012-12-01

    This paper presents an advancement of the recently developed particle-resolved aerosol model PartMC-MOSAIC (Particle Monte Carlo-Model for Simulating Aerosol Interactions and Chemistry) to investigate the impacts of mixing state on cloud droplet formation and to provide a tool for the quantification of errors in cloud properties introduced by simplifying mixing state assumptions. We coupled PartMC-MOSAIC with a cloud parcel model. We initialized the cloud parcel simulation with hourly PartMC-MOSAIC model output from a 48-hour urban plume simulation. The cloud parcel model then explicitly simulated activation and condensational growth of the particles as the parcel underwent cooling at a specified rate and the particles of the aerosol population competed for water vapor. We used this capability to quantify the relative importance of size information versus composition information for the prediction of the cloud droplet number fraction, mass fraction of black carbon that is nucleation-scavenged, cloud droplet effective radius, and relative dispersion of the droplet size distribution by introducing averaging of particle-resolved information within prescribed bins. For the cloud droplet number fraction, both composition averaging and size-bin averaging individually led to an error of less than 25% for all cloud parcel simulations, while averaging in both size bins and composition resulted in errors of up to 34% for the base case cooling rate of 0.5 K/min. In contrast, for the nucleation-scavenged black carbon mass fraction, the results for size-bin averaging tracked the reference case well, while composition averaging, with or without size-bin averaging, led to overestimation of this quantity by up to 600%.

  7. Nanoscale mapping of carbon oxidation in pyrogenic black carbon from ancient Amazonian anthrosols.

    PubMed

    Archanjo, B S; Baptista, D L; Sena, L A; Cançado, L G; Falcão, N P S; Jorio, A; Achete, C A

    2015-04-01

    Understanding soil organic matter is necessary for the development of soil amendments, which are important for sustaining agriculture in humid tropical climates. Ancient Amazonian anthrosols are uniquely high in black recalcitrant carbon, making them extremely fertile. In this study, we use high-resolution electron microscopy and spectroscopy to resolve the oxidation process of carbon in the nanoscale crystallites within the black carbon grains of this special soil. Most alkali and acid chemical extraction methods are known to cause chemical modifications in soil organic matter and to give poor or no information about the real spatial structure of soil aggregates. However, here we show that carbon-oxygen functional groups such as phenol, carbonyl, and carboxyl dominate over different spatial regions, with areas varying from over tens to hundreds of nm(2). The chemical maps show that in the nanoscale grain, the surface has a tendency to be less aromatic than the grain core, where higher oxidative-degradation levels are indicated by the presence of carbonyl and carboxyl groups. A deep understanding of these structures could allow artificial reproduction of these natural events. PMID:25699655

  8. Uptake Mechanism for Iodine Species to Black Carbon

    SciTech Connect

    Choung, Sungwook; Um, Wooyong; Kim, Min Kyung; Kim, Min-Gyu

    2013-08-13

    Natural organic matter (NOM) plays an important role in determining the fate and transport of iodine species such as iodide (I-) and iodate (IO3-) in groundwater system. Although NOM exists as diverse forms in environments, prior iodine studies have mainly focused on uptake processes of iodide and iodate to humic materials. This study was conducted to determine the iodide and iodate uptake potential for a particulate NOM (i.e., black carbon [BC]). A laboratory-produced BC and commercial humic acid were used for batch experiments to compare their iodine uptake properties. The BC exhibited >100 times greater uptake capability for iodide than iodate at low pH~3, while iodide uptake was negligible for the humic acid. The uptake properties of both solids strongly depend on the initial iodine aqueous concentrations. After uptake reaction of iodide to the BC, X-ray Absorption Fine Structure spectroscopy results indicated that the iodide was converted to electrophilic species, and iodine was covalently bound to carbon atom in polycyclic aromatic hydrocarbons present in the BC. The computed distribution coefficients (i.e., Kd values) suggest that the BC materials retard significantly the transport of iodide at low pH in environmental systems containing even a small amount of BC.

  9. Dissolved Black Carbon in the South China Sea

    NASA Astrophysics Data System (ADS)

    Fang, Z.; Yang, W.; Chen, M.; Ma, H.

    2015-12-01

    Dissolved black carbon (DBC) has been ubiquitously reported in dissolved organic matter (DOM). However, the abundance and provenance of DBC in the ocean are not well understood. Here, DBC in the South China Sea (SCS) was determined at molecular level using the benzenepolycarboxylic acids (BPCAs) method. DBC showed high concentrations in the upper 100 m seawater with the average of 1.13 μmol l-1 (n=55). In the intermediate seawater (200-1500 m), DBC ranged from 0.67 to 0.89 μmol l-1 with the average of 0.78 μmol l-1 (n=9), exhibiting nearly homogeneous distributions. The vertical distribution pattern indicated that DBC significantly degraded in the photic zone, corresponding to an attenuate constant of 12.5±4.9 km-1. The ratios of B6CA/B3CAs increased downward, implying that aromatic condensation degree of DBC increase during transport from surface to deep water. Using the standing crops of DBC in the upper 200 m and the residence time of seawater, atmospheric deposition of DBC was estimated to be 1.94 TgC yr-1, accounting for around 16% of the global BC deposition. Our study highlights that DBC could be an important component of ocean carbon cycling in Pacific Asia Marginal Seas.

  10. Photo-lability of deep ocean dissolved black carbon

    NASA Astrophysics Data System (ADS)

    Stubbins, A.; Niggemann, J.; Dittmar, T.

    2012-05-01

    Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzenepolycarboxylic acid (BPCA) oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 day irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM-C to 55 ± 15 nM-C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. The concentration of DBC correlated with CDOM absorbance and the quality of DBC indicated by the ratios of different BPCAs correlated with CDOM absorbance spectral slope, suggesting the optical properties of CDOM may provide a proxy for both DBC concentrations and quality in natural waters. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 years. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Consequently, photo-degradation is posited as the primary sink for oceanic DBC and the apparent survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but

  11. Synthesis of carbon black/polystyrene conductive nanocomposite. Pickering emulsion effect characterized by TEM.

    PubMed

    Zaragoza-Contreras, Erasto Armando; Hernández-Escobar, Claudia Alejandra; Navarrete-Fontes, Alfredo; Flores-Gallardo, Sergio Gabriel

    2011-04-01

    In this study, carbon black/polystyrene electrically conductive composites were obtained by suspension polymerization technique. The composite was characterized using transmission electron microscopy, which indicated two outstanding features concerning to the carbon black; first, that the carbon particles were adsorbed onto the surface of the polystyrene particles, similarly as in the Pickering emulsion phenomenon and second, that the primary aggregate structure of the carbon black was significantly affected by the dispersion process. On the other hand, the composite resistivity was in the order of 200 Ωcm, which was attributed to the direct contact of primary carbon black particles (percolation) and not to the tunneling effect. The obtained composite was evaluated as the electrically conductive element in SBR matrix. PMID:21131206

  12. An approach to a black carbon emission inventory for Mexico by two methods.

    PubMed

    Cruz-Núñez, Xochitl

    2014-05-01

    A black carbon (BC) emission inventory for Mexico is presented. Estimate was performed by using two approaches, based on fuel consumption and emission factors in a top-down scheme, and the second from PM25 emission data and its correlation with black carbon by source category, assuming that black carbon=elemental carbon. Results show that black carbon emissions are in interval 53-473Gg using the fuel consumption approach and between 62 and 89 using the sector method. Black carbon key sources come from biomass burning in the rural sector, with 47 percent share to the National total. Mobile sources emissions account to 16% to the total. An opportunity to reduce, in the short-term, carbon dioxide equivalent (CO2-eq) emissions by reducing black carbon emissions would be obtained in reducing emissions mainly from biomass burning in rural housing sector and diesel emissions in the transport sector with important co-benefits in direct radiative forcing, public health and air quality. PMID:24561296

  13. Cohort Study of Carbon Black Exposure and Risk of Malignant and Nonmalignant Respiratory Disease Mortality in the US Carbon Black Industry

    PubMed Central

    Dell, Linda D.; Gallagher, Alexa E.; Crawford, Lori; Jones, Rachael M.; Mundt, Kenneth A.

    2015-01-01

    Objective: To evaluate lung cancer and respiratory disease mortality associations with cumulative inhalable carbon black exposure among 6634 US carbon black workers. Methods: This analysis was performed using standardized mortality ratio (SMRs) and Cox regression analyses. Results: Lung cancer mortality was decreased overall (SMR = 0.77; 95% confidence interval [CI], 0.67 to 0.89) but less so among hourly male workers (SMR = 0.87; 95% CI, 0.71 to 1.05). No exposure–response association was observed with time-dependent cumulative inhalable carbon black: hazard ratio [HR] = 1.0 (95% CI, 0.6 to 1.6) for 20 to less than 50 mg/m3·yr); HR = 1.3 (95% CI, 0.8 to 2.1) for 50 to less than 100 mg/m3·yr; and HR = 1.4 (95% CI, 0.9 to 2.1) for 100 mg/m3·yr or more compared with referent (<20 mg/m3·yr). No consistent associations were observed between cumulative inhalable carbon black exposure and respiratory disease mortality. Conclusion: Quantitative carbon black exposure estimates were not related to lung cancer or nonmalignant respiratory disease mortality. PMID:26340287

  14. Analyzing carbon dioxide and methane emissions in California using airborne measurements and model simulations

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Yates, E. L.; Iraci, L. T.; Jeong, S.; Fischer, M. L.

    2013-12-01

    Greenhouse gas (GHG) concentrations have increased over the past decades and are linked to global temperature increases and climate change. These changes in climate have been suggested to have varying effects, and uncertain consequences, on agriculture, water supply, weather, sea-level rise, the economy, and energy. To counteract the trend of increasing atmospheric concentrations of GHGs, the state of California has passed the California Global Warming Act of 2006 (AB-32). This requires that by the year 2020, GHG (e.g., carbon dioxide (CO2) and methane (CH4)) emissions will be reduced to 1990 levels. To quantify GHG fluxes, emission inventories are routinely compiled for the State of California (e.g., CH4 emissions from the California Greenhouse Gas Emissions Measurement (CALGEM) Project). The major sources of CO2 and CH4 in the state of California are: transportation, electricity production, oil and gas extraction, cement plants, agriculture, landfills/waste, livestock, and wetlands. However, uncertainties remain in these emission inventories because many factors contributing to these processes are poorly quantified. To alleviate these uncertainties, a synergistic approach of applying air-borne measurements and chemical transport modeling (CTM) efforts to provide a method of quantifying local and regional GHG emissions will be performed during this study. Additionally, in order to further understand the temporal and spatial distributions of GHG fluxes in California and the impact these species have on regional climate, CTM simulations of daily variations and seasonality of total column CO2 and CH4 will be analyzed. To assess the magnitude and spatial variation of GHG emissions and to identify local 'hot spots', airborne measurements of CH4 and CO2 were made by the Alpha Jet Atmospheric eXperiment (AJAX) over the San Francisco Bay Area (SFBA) and San Joaquin Valley (SJV) in January and February 2013 during the Discover-AQ-CA study. High mixing ratios of GHGs were

  15. Oxidation of Black Carbon by Biotic and Abiotic Processes

    SciTech Connect

    Cheng, Chih-hsin; Lehmann, Johannes C.; Thies, Janice E.; Burton, Sarah D.; Engelhard, Mark H.

    2006-11-01

    The objectives of this study were to quantify the relative importance of either biotic or abiotic oxidation of biomass-derived black carbon (BC) and to characterize the surface properties and charge characteristics of oxidized particulate BC. We incubated BC and BC-soil mixtures at two different temperatures (30 C and 70 C) with and without microbial inoculation, nutrient additions, or manure amendments for four months. Abiotic processes were more important for oxidation of BC than biotic processes during this short-term incubation, as inoculation with microorganisms did not change any of the measured parameters. Black C incubated at both 30 C and 70 C without microbial activity showed dramatic decreases in pH (in water) from 5.4 to 5.2 and 3.4, as well as increases in cation exchange capacity (CEC at pH 7) by 53% and 538% and in oxygen (O) contents by 4% and 38%, respectively. Boehm titration and Fourier transform infrared (FTIR) spectroscopy suggested that the formation of carboxylic functional groups was the reason for the enhanced CEC during oxidation. The analyses of BC surface properties by X-ray photoelectron spectroscopy (XPS) indicated that the oxidation of BC particles initiated on the surface. Incubation at 30 C only enhanced oxidation on particle surfaces, while oxidation during incubation at 70 C penetrated into the interior of particles. Such short-term oxidation of BC has great significance for the stability of BC in soils as well as for its effects on soil fertility and biogeochemistry.

  16. Variable effects of labile carbon on the carbon use of different microbial groups in black slate degradation

    NASA Astrophysics Data System (ADS)

    Seifert, Anne-Gret; Trumbore, Susan; Xu, Xiaomei; Zhang, Dachung; Kothe, Erika; Gleixner, Gerd

    2011-05-01

    Weathering of ancient organic matter contributes significantly to biogeochemical carbon cycles over geological times. The principle role of microorganisms in this process is well recognized. However, information is lacking on the contribution of individual groups of microorganisms and on the effect of labile carbon sources to the degradation process. Therefore, we investigated the contribution of fungi, Gram-positive and Gram-negative bacteria in the degradation process using a column experiment. Investigations were performed on low metamorphic black slates. All columns contained freshly crushed, sieved (0.63-2 mm), not autoclaved black slates. Two columns were inoculated with the lignite-degrading fungus Schizophyllum commune and received a culture medium containing 13C labeled glucose, two columns received only this culture medium and two control columns received only water. The total mass balance was calculated from all carbon added to the slate and the CO 2 and DOC losses. Phospholipid fatty acids (PLFA) were extracted to investigate microbial communities. We used both the compound specific 14C and 13C signal of the PLFA to quantify carbon uptake from black slates and the glucose of the culture medium, respectively. The total carbon loss in these columns exceeded the amount of added carbon by approximately 60%, indicating that black slate carbon has been used. PLFA associated with Gram-positive bacteria dominated the indigenous community and took up 22% of carbon from black slate carbon, whereas PLFA of Gram-negative bacteria used only 8% of carbon from the slates. PLFA of Gram-negative bacteria and fungi were both mostly activated by the glucose addition. The added Schizophyllum did not establish well in the columns and was overgrown by the indigenous microbial community. Our results suggest that especially Gram-positive bacteria are able to live on and degrade black slate material. They also benefit from easy degradable carbon from the nutrient broth. In

  17. Retrieval of Black Carbon Absorption from Proposed Satellite Measurements Over the Ocean Glint

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Matins, J. V.; Remer, L. A.; Schoeberl, M. R.; Yamasoe, M. A.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    Haze and air pollution includes many chemicals that together form small particles suspended in the air called aerosols. One of the main ingredients found to affect climate and human health is Black Carbon. Black particles emitted from engines that do not burn the fuel completely, e.g. old trucks. Black carbon absorption of sunlight emerges as one of the key components of man-made forcing of climate. However, global characterization of black carbon emissions, distribution and pathways in which it can affect the amount of solar radiation absorbed by the atmosphere is very uncertain. A new method is proposed to measure sunlight absorption by fine aerosol particles containing black carbon over the ocean glint from a satellite mission designed for this purpose. The satellite will scan the same spot over the ocean in the glint plane and a plane 40 degrees off-glint a minute apart, collecting measurements of the reflected light across the solar spectrum. First the dark ocean off the glint is used to derive aerosol properties. Then the black carbon absorption is derived prop the attenuation of the bright glint by the aerosol layer. Such measurements if realized in a proposed future mission - COBRA are expected to produce global monthly climatology of black carbon absorption with high accuracy (110 to 15%) that can show their effect on climate.

  18. Effect Of Black Carbon Radiative Heating On Cloud Microphysics Over Indo-Gangetic Basin

    NASA Astrophysics Data System (ADS)

    Ghosh, A.; Tripathi, S. N.

    2008-12-01

    Airborne black carbon (BC), the most significant particulate absorber of solar radiation in the atmosphere, is an important contributor to both global and regional-scale climate forcing (Tripathi et al., 2005). In context of cloud microphysics, freshly emitted pure BC particles are hydrophobic (i.e., bad cloud condensation nuclei (CCN)). However, exposure in the atmosphere may transform BC to a hydrophilic state if these particles are coated with additional materials, such as sulfate and organic carbon (OC). In a recent study, Conant et al. (2002) has examined the effect of radiative heating of BC on the critical supersaturation spectrum of internally mixed aerosols. Two main uncertainties introduced in this work are due to lack of knowledge of actual state of mixing and realistic distributions of different aerosol species. Indo-Gangetic Basin (IGB) in the northern India is one of the most polluted regions in the world. The cloud microphysical processes in IGB are very complex and it requires an in depth investigation for understanding of the aerosol-cloud interaction in the region (Tripathi, et al., 2007). In the present work, an attempt has been made to study the effect of radiative heating due to BC particles coated with hydrophilic materials on cloud microphysics over IGB. For this purpose, we have used (a) a two-layer radiative parameter model based on Mie theory (Toon and Ackerman, 1981) to calculate the particle (monodisperse) absorption cross section; (b) a three-dimensional (3D) radiative transfer model, the spherical harmonics discrete ordinate method (SHDOM) (Evans,1998), which assumes a tropical continental atmosphere, to simulate the 3D spectral actinic flux over the study region; and (c) Extended Köhler theory (Conant et al., 2002) to simulate the effect the BC radiative heating on cloud droplet activation. The solar wavelength spectrum used ranges from 0.2 to 5 micrometer. Following the in situ measurements and modeling studies on mixing state (Dey

  19. ARM Airborne Carbon Measurements (ARM-ACME) and ARM-ACME 2.5 Final Campaign Reports

    SciTech Connect

    Biraud, S. C.; Tom, M. S.; Sweeney, C.

    2016-01-01

    We report on a 5-year multi-institution and multi-agency airborne study of atmospheric composition and carbon cycling at the Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains (SGP) site, with scientific objectives that are central to the carbon-cycle and radiative-forcing goals of the U.S. Global Change Research Program and the North American Carbon Program (NACP). The goal of these measurements is to improve understanding of 1) the carbon exchange of the Atmospheric Radiation Measurement (ARM) SGP region; 2) how CO2 and associated water and energy fluxes influence radiative-forcing, convective processes, and CO2 concentrations over the ARM SGP region, and 3) how greenhouse gases are transported on continental scales.

  20. Carbon stocks and cycling in the Amazon basin: Measurement and modeling of natural disturbance and recovery using airborne LIDAR

    NASA Astrophysics Data System (ADS)

    Hunter, Maria O'Healy

    Forest structure, the three dimensional distribution of living and dead plant material including live crowns, understory vegetation and coarse woody debris, is the concrete physical form of carbon storage, the framework for biodiversity, and the instantaneous manifestation of disturbance and recovery processes. The frequency of disturbance and rate of decomposition drives the fractions of living and dead biomass, and the size of and intensity of disturbance drives the rate and species composition of forest recovery; both are primary sinks and sources in the carbon cycle. To improve understanding of disturbance and recovery processes, high-resolution airborne LIDAR (light detection and ranging) data from the Amazon region is combined with field measurements to analyze forest structure. These measurements are incorporated into a simple model to estimate light availability and the associated changes in carbon stocks. This work improves the understanding of Amazon forest dynamics and its role in the carbon cycle.

  1. Testing of a Two-Micron Double-Pulse IPDA Lidar Instrument for Airborne Atmospheric Carbon Dioxide Measurement

    NASA Astrophysics Data System (ADS)

    Yu, J.; Petros, M.; Refaat, T. F.; Remus, R.; Singh, U. N.

    2015-12-01

    Utilizing a tunable two-micron double-pulse laser transmitter, an airborne IPDA lidar system has been developed at NASA Langley Research Center for atmospheric carbon dioxide column measurements. The instrument comprises a receiver with 0.4 m telescope and InGaAs pin detectors coupled to 12-bit, 200 MS/s waveform digitizers. For on-site ground testing, the 2-μm CO2 IPDA lidar was installed inside a trailer located where meteorological data and CO2 mixing ratio profiles were obtained from CAPABLE and LiCoR in-suite sampling, respectively. IPDA horizontal ground testing with 860 m target distance indicated CO2 sensitivity of 2.24 ppm with -0.43 ppm offset, while operating at 3 GHz on-line position from the R30 line center. Then, the IPDA lidar was integrated inside the NASA B-200 aircraft, with supporting instrumentation, for airborne testing and validation. Supporting instruments included in-situ LiCoR sensor, GPS and video recorder for target identification. Besides, aircraft built-in sensors provided altitude, pressure, temperature and relative humidity sampling during flights. The 2-mm CO2 IPDA lidar airborne testing was conducted through ten daytime flights (27 hours flight time). Airborne testing included different operating and environmental conditions for flight altitude up to 7 km, different ground target conditions such as vegetation, soil, ocean, snow and sand and different cloud conditions. Some flights targeted power plant incinerators for investigating IPDA sensitivity to CO2 plums. Relying on independent CO2 in-situ sampling, conducted through NOAA, airborne IPDA CO2 sensitivity of 4.15 ppm with 1.14 ppm offset were observed at 6 km altitude and 4 GHz on-line offset frequency. This validates the 2-μm double-pulse IPDA lidar for atmospheric CO2 measurement.

  2. Raman spectroscopic investigation of carbon-based materials and their composites. Comparison between carbon nanotubes and carbon black

    NASA Astrophysics Data System (ADS)

    Bokobza, Liliane; Bruneel, Jean-Luc; Couzi, Michel

    2013-12-01

    Raman spectroscopy experiments on multiwall carbon nanotube (MWCNTs), carbon black (CB) and on a styrene-butadiene rubber (SBR) filled either with MWCNTs or CB and also with a mixture of both particles (MWCNTs + CB) are reported. Emphasis is given on the dispersive effects of the Raman D band with laser energy that are shown for the first time to differ in each type of composites revealing a different polymer-filler interface. In addition, an upshift of the G band is observed when CB particles are incorporated into the polymer matrix.

  3. Quantifying sources, transport, deposition and radiative forcing of black carbon over the Himalayas and Tibetan Plateau

    DOE PAGESBeta

    Zhang, R.; Wang, H.; Qian, Y.; Rasch, P. J.; Easter, R. C.; Ma, P. -L.; Singh, B.; Huang, J.; Fu, Q.

    2015-01-07

    Black carbon (BC) particles over the Himalayas and Tibetan Plateau (HTP), both airborne and those deposited on snow, have been shown to affect snowmelt and glacier retreat. Since BC over the HTP may originate from a variety of geographical regions and emission sectors, it is essential to quantify the source–receptor relationships of BC in order to understand the contributions of natural and anthropogenic emissions and provide guidance for potential mitigation actions. In this study, we use the Community Atmosphere Model version 5 (CAM5) with a newly developed source tagging technique, nudged towards the MERRA meteorological reanalysis, to characterize the fatemore » of BC particles emitted from various geographical regions and sectors. Evaluated against observations over the HTP and surrounding regions, the model simulation shows a good agreement in the seasonal variation of the near-surface airborne BC concentrations, providing confidence to use this modeling framework for characterizing BC source–receptor relationships. Our analysis shows that the relative contributions from different geographical regions and source sectors depend on seasons and the locations in the HTP. The largest contribution to annual mean BC burden and surface deposition in the entire HTP region is from biofuel and biomass (BB) emissions in South Asia, followed by fossil fuel (FF) emissions from South Asia, then FF from East Asia. The same roles hold for all the seasonal means except for the summer when East Asia FF becomes more important. For finer receptor regions of interest, South Asia BB and FF have the largest impact on BC in Himalayas and Central Tibetan Plateau, while East Asia FF and BB contribute the most to Northeast Plateau in all seasons and Southeast Plateau in the summer. Central Asia and Middle East FF emissions have relatively more important contributions to BC reaching Northwest Plateau, especially in the summer. Although local emissions only contribute about 10% to

  4. Quantifying sources, transport, deposition, and radiative forcing of black carbon over the Himalayas and Tibetan Plateau

    DOE PAGESBeta

    Zhang, R.; Wang, H.; Qian, Y.; Rasch, P. J.; Easter, R. C.; Ma, P. -L.; Singh, B.; Huang, J.; Fu, Q.

    2015-06-08

    Black carbon (BC) particles over the Himalayas and Tibetan Plateau (HTP), both airborne and those deposited on snow, have been shown to affect snowmelt and glacier retreat. Since BC over the HTP may originate from a variety of geographical regions and emission sectors, it is essential to quantify the source–receptor relationships of BC in order to understand the contributions of natural and anthropogenic emissions and provide guidance for potential mitigation actions. In this study, we use the Community Atmosphere Model version 5 (CAM5) with a newly developed source-tagging technique, nudged towards the MERRA meteorological reanalysis, to characterize the fate ofmore » BC particles emitted from various geographical regions and sectors. Evaluated against observations over the HTP and surrounding regions, the model simulation shows a good agreement in the seasonal variation in the near-surface airborne BC concentrations, providing confidence to use this modeling framework for characterizing BC source–receptor relationships. Our analysis shows that the relative contributions from different geographical regions and source sectors depend on season and location in the HTP. The largest contribution to annual mean BC burden and surface deposition in the entire HTP region is from biofuel and biomass (BB) emissions in South Asia, followed by fossil fuel (FF) emissions from South Asia, then FF from East Asia. The same roles hold for all the seasonal means except for the summer, when East Asia FF becomes more important. For finer receptor regions of interest, South Asia BB and FF have the largest impact on BC in the Himalayas and central Tibetan Plateau, while East Asia FF and BB contribute the most to the northeast plateau in all seasons and southeast plateau in the summer. Central Asia and Middle East FF emissions have relatively more important contributions to BC reaching the northwest plateau, especially in the summer. Although local emissions only contribute about

  5. Quantifying sources, transport, deposition, and radiative forcing of black carbon over the Himalayas and Tibetan Plateau

    SciTech Connect

    Zhang, Rudong; Wang, Hailong; Qian, Yun; Rasch, Philip J.; Easter, Richard C.; Ma, Po-Lun; Singh, Balwinder; Huang, Jianping; Fu, Qiang

    2015-01-01

    Black carbon (BC)particles over the Himalayas and Tibetan Plateau (HTP), both airborne and those deposited on snow, have been shown to affect snowmelt and glacier retreat. Since BC over the HTP may originate from a variety of geographical regions and emission sectors, it is essential to quantify the source-receptor relationships of BC in order to understand the contributions of natural and anthropogenic emissions and provide guidance for potential mitigation actions. In this study, we use the Community Atmosphere Model version 5 (CAM5) with a newly developed source tagging technique, nudged towards the MERRA meteorological reanalysis, to characterize the fate of BC particles emitted from various geographical regions and sectors. Evaluated against observations over the HTP and surrounding regions, the model simulation shows a good agreement in the seasonal variation of the near-surface airborne BC concentrations, providing confidence to use this modeling framework for characterizing BC source- receptor relationships. Our analysis shows that the relative contributions from different geographical regions and source sectors depend on seasons and the locations in the HTP. The largest contribution to annual mean BC burden and surface deposition in the entire HTP region is from biofuel and biomass (BB) emissions in South Asia, followed by fossil fuel (FF) emissions from South Asia, then FF from East Asia. The same roles hold for all the seasonal means except for the summer when East Asia FF becomes more important. For finer receptor regions of interest, South Asia BB and FF have the largest impact on BC in Himalayas and Central Tibetan Plateau, while East Asia FF and BB contribute the most to Northeast Plateau in all seasons and Southeast Plateau in the summer. Central Asia and Middle East FF emissions have relatively more important contributions to BC reaching Northwest Plateau, especially in the summer. Although the HTP local emissions only contribute about 10% of BC in

  6. Black carbon, a 'hidden' player in the global C cycle

    NASA Astrophysics Data System (ADS)

    Santín, C.; Doerr, S. H.

    2012-04-01

    During the 2011 alone more than 600 scientific papers about black carbon (BC) were published, half of them dealing with soils (ISI Web of Knowledge, accessed 15/01/2012). If the search is extended to the other terms by which BC is commonly named (i.e. biochar, charcoal, pyrogenic C or soot), the number of 2011 publications increases to >2400, 20% of them also related to soils. These figures confirm BC as a well-known feature in the scientific literature and, thus, in our research community. In fact, there is a wide variety of research topics where BC is currently studied: from its potential as long-term C reservoir in soils (man-made biochar), to its effects on the Earth's radiation balance (soot-BC), including its value as indicator in paleoenvironmental studies (charcoal) or, even surprisingly, its use in suicide attempts. BC is thus relevant to many aspects of our environment, making it a very far-reaching, but also very complex topic. When focusing 'only' on the role of BC in the global C cycle, numerous questions arise. For example: (i) how much BC is produced by different sources (i.e. vegetation fires, fossil fuel and biofuel combustion); (ii) what are the main BC forms and their respective proportions generated (i.e. proportion of atmospheric BC [BC-soot] and the solid residues [char-BC]); (iii) where does this BC go (i.e. main mobilization pathways and sinks); (iv) how long does BC stay in the different systems (i.e. residence times in soils, sediments, water and atmosphere); (v) which are the BC stocks and its main transformations within and between the different systems (i.e. BC preservation, alteration and mineralization); (vi) what is the interaction of BC with other elements and how does this influence BC half-life (i.e. physical protection, interaction with pollutants, priming effects in other organic materials)? These questions, and some suggestions about how to tackle these, will be discussed in this contribution. It will focus in particular on the

  7. Comparison Between Elemental Carbon Measured Using Thermal-Optical Analysis and Black Carbon Measurements Using A Novel Cellphone-Based System

    NASA Astrophysics Data System (ADS)

    Ramanathan, N.; Khan, B.; Leong, I.; Lukac, M.

    2011-12-01

    Black carbon (BC) is produced through the incomplete combustion of fossil and solid fuels. Current BC emissions inventories have large uncertainties of factors of 2 or more due to sparse measurements and because BC is often emitted by local sources that vary over time and space (Bond et al, 2004). Those uncertainties are major sources of error in air pollution models. Emissions from a variety of improved cookstove/fuel/combustion conditions were collected on pre-conditioned 47 mm quartz-fiber filters and analyzed for organic carbon (OC) and elemental carbon (EC) using thermal-optical analysis (TOA). The samples were then analyzed for BC concentration by using cellphone-based instrumentation developed by Ramanathan et al., 2011. The cellphone-based monitoring system (CBMS) is a wireless, low-cost, low-power system that monitors BC emissions. The CBMS is comprised of an aerosol filter sampler containing a battery-powered air pump and a 25mm filter holder that draws air in through a quartz-fiber filter. As black carbon deposits increase, the filter darkens--the darkest color representing the highest loading. A cellphone photograph of the filter with the black carbon deposit is taken and relayed to an analytics unit for comparison to a reference scale to estimate airborne BC concentration. The BC concentration can then be compared to the thermally derived EC concentration. TOA was conducted on a Sunset Laboratory Dual Optics Carbon Analyzer using a modified version of the Birch and Cary (1996) NIOSH 5040 protocol. The dual-optical instrument permitted simultaneous monitoring of the transmission (TOT) and reflectance (TOR). 619 samples were collected; EC was obtained using NIOSH TOT and NIOSH TOR methods, and BC was obtained using the CBMS analytics unit. The mean BC value reported by the CBMS agrees within 20% of the reference values for EC, confirming the findings in Ramanathan et al. (2011) based on samples from India. Given this accuracy, we conclude that the CBMS

  8. Carbon black nanoparticles and other problematic constituents of black ink and their potential to harm tattooed humans.

    PubMed

    Jacobsen, Nicklas Raun; Clausen, Per Axel

    2015-01-01

    Black is the most common tattoo color, but only a few studies have shed light on the multitude of functional and contaminating chemicals present in black inks. These studies have generally shown that black inks are a diverse group, containing anything from 5 to 50+ organic components. Little is known about the possible effects on humans of internalizing these chemicals. Analysis has shown that the production of the main component, carbon black, can lead to the formation of pigments with polycyclic aromatic hydrocarbon (PAH) contents that range from very high to almost completely absent. Similar variations in PAH concentrations are observed in black inks. PAHs are known carcinogens and thus, low recommended levels have been suggested by the Council of Europe. Reactive oxygen species (ROS) have recently been a topic in scientific literature related to tattoo ink. Again, it has been shown that some inks produce deleterious ROS (e.g. singlet oxygen or peroxyl radicals), presumably via either adhered organic compounds or particle surface defects. It has been shown that black tattoo inks may contain a multitude of chemicals, including carcinogens and allergens, and some have unknown toxicologies. However, it has additionally been demonstrated that some black inks already on the market do not produce ROS and also contain PAHs at levels that are below those recommended by the Council of Europe and very few additional contaminants. PMID:25833640

  9. Measurements of black carbon particles’ chemical, physical, and optical properties (Invited)

    NASA Astrophysics Data System (ADS)

    Onasch, T. B.; Cross, E. S.; Davidovits, P.; Worsnop, D. R.; Ahern, A.; Lack, D. A.; Cappa, C. D.; Trimborn, A.; Freedman, A.; Olfert, J. S.; Jayne, J. T.; Massoli, P.; Williams, L. R.; Mazzoleni, C.; Schwarz, J. P.; Thornhill, D. A.; Slowik, J. G.; Kok, G. L.; Brem, B. T.; Subramanian, R.; Sedlacek, A. J.; Spackman, J. R.; Freitag, S.; Dubey, M. K.

    2009-12-01

    Accurate measurements of the chemical, physical, and optical properties of aerosol particles containing black carbon are necessary to improve current estimates of the radiative forcing in the atmosphere. A collaborative research effort between Aerodyne Research, Inc. and Boston College has focused on conducting field and laboratory experiments on carbonaceous particles and the development and characterization of new particulate instrumentation. This presentation will focus on the chemical, physical, and optical properties of black carbon particles measured in the laboratory in order to understand the effects of atmospheric processing on black carbon particles. Results from a three-week study during July 2008 of mass- and optical-based black carbon measurements will be presented. The project utilized the Boston College laboratory flame apparatus and aerosol conditioning and characterization equipment. A pre-mixed flat flame burner operating at controlled fuel-to-air ratios produced stable and reproducible concentrations of soot particles with known sizes, morphologies, and chemical compositions. In addition, other black carbon particle types, including fullerene soot, glassy carbon spheres, oxidized flame soot, Regal black, and Aquadag, were also atomized, size selected, and sampled. The study covered an experimental matrix that systematically selected particle mobility size (30 to 300 nm) and black carbon particle mass, particle number concentration, particle shape (dynamic shape factor and fractal dimension), and particle chemistry and density (changed via coatings). Particles were coated with a measured thickness (few nm to ~150 nm) of sulfuric acid or bis (2-ethylhexyl) sebacate and passed through a thermal denuder to remove the coatings. Highlights of the study to be presented include: (1) Characterization of the chemical and physical properties of various types of black carbon particles, (2) Mass specific absorption measurements as a function of fuel

  10. Estimation of polyurethane-carbon black interactions by means of inverse gas chromatography.

    PubMed

    Strzemiecka, Beata; Voelkel, Adam; Donate-Robles, Jessica; Martín-Martínez, José Miguel

    2013-11-01

    The properties of composites depend mainly on the interfacial interactions between filler and matrix that can be related to the adhesion between filler and polymer matrix. In this study the work of cohesion between the carbon black particles - Wcoh - and the thermodynamic work of adhesion - Wa - between four carbon blacks of different specific surface area and surface chemistry (nature and content of carbon-oxygen functional groups) and thermoplastic polyurethane were calculated by means of inverse gas chromatography (IGC) at infinite dilution. IGC derived data indicated that the work of adhesion increased by increasing the surface area of the carbon black, but the opposite trend was found in Wa/Wcoh and work of cohesion. According to the Wa/Wcoh values the filler particles should be well dispersed into the polyurethane matrix giving homogenous composites. The carbon black-thermoplastic polyurethane interactions determined by plate-plate rheology showed the same trend than that for the Wa/Wcoh values. However, the thermodynamic work of adhesion values derived from IGC were not in agreement with the carbon black-polyurethane interfacial interactions, likely due to the dominant effect of the carbon black in reducing the crystallinity and increasing the degree of phase separation of the thermoplastic polyurethane. PMID:24063983

  11. Taking stock of circumboreal forest carbon by combining inventory plot measurements with airborne and spaceborne LiDAR

    NASA Astrophysics Data System (ADS)

    Neigh, C. S.; Nelson, R. F.; Ranson, J.; Margolis, H. A.; Montesano, P. M.; Sun, G.; Kharuk, V.; Næsset, E.; Wulder, M. A.; Andersen, H.

    2013-12-01

    The boreal forest accounts for one-third of global forests, but remains largely inaccessible to ground-based measurements and monitoring. It contains large quantities of carbon in its vegetation and soils, and research suggests that it will be subject to increasingly severe climate-driven disturbance. We employ a suite of ground-, airborne- and space-based measurement techniques to derive the first satellite LiDAR-based estimates of aboveground carbon for the entire circumboreal forest biome. Incorporating these inventory techniques with uncertainty analysis, we estimate total aboveground carbon of 38 × 3.1 Pg. This boreal forest carbon is mostly concentrated from 50 to 55° N in eastern Canada and from 55 to 60° N in eastern Eurasia. Both of these regions are expected to warm > 3 °C by 2100, and monitoring the effects of warming on these stocks is important to understanding its future carbon balance. Our maps establish a baseline for future quantification of circumboreal carbon and the described technique should provide a robust method for future monitoring of the spatial and temporal changes of the aboveground carbon content. Circumboreal forest. a, aboveground carbon. b,c Error estimates of carbon density.

  12. Mass spectrometry of refractory black carbon particles from six sources: carbon-cluster and oxygenated ions

    NASA Astrophysics Data System (ADS)

    Corbin, J. C.; Sierau, B.; Gysel, M.; Laborde, M.; Keller, A.; Kim, J.; Petzold, A.; Onasch, T. B.; Lohmann, U.; Mensah, A. A.

    2013-10-01

    We discuss the major mass spectral features of different types of refractory carbonaceous particles, ionized after laser vapourization with an Aerodyne High-Resolution Soot-Particle Aerosol Mass Spectrometer (SP-AMS). The SP-AMS was operated with a switchable 1064 nm laser and a 600 °C thermal vapourizer, yielding respective measurements of the refractory and non-refractory particle components. Six samples were investigated, all of which were composed primarily of refractory material: fuel-rich and fuel-lean propane/air diffusion-flame combustion particles; graphite-spark-generated particles; a commercial Fullerene-enriched Soot; Regal Black, a commercial carbon black; and nascent aircraft-turbine combustion particles. All samples exhibited a spectrum of carbon-cluster ions Cxn+ in their refractory mass spectrum. Smaller clusters (x<6) were found to dominate the Cxn+ distribution. For Fullerene Soot, fuel-rich-flame particles and spark-generated particles, significant Cxn+ clusters at x≫6 were present, with significant contributions from multiply-charged ions (n>1). In all six cases, the ions C1+ and C3+ contributed over 60% to the total C15 were present. When such signals were present, C1+/C3+ was close to 1. When absent, C1+/C3+ was <0.8. This ratio may therefore serve as a proxy to distinguish between the two types of spectra in atmospheric SP-AMS measurements. Significant refractory oxygenated ions such as CO+ and CO2+ were also observed for all samples. We discuss these signals in detail for Regal Black, and describe their formation via decomposition of oxygenated moieties incorporated into the refractory carbon structure. These species may be of importance in atmospheric processes such as water uptake, aging and heterogeneous chemistry.

  13. Modern biofuels life-cycle effects on black carbon emissions and impacts

    NASA Astrophysics Data System (ADS)

    Campbell, J.; Spak, S.; Mena-Carrasco, M.; Carmichael, G. R.; Chen, Y.; Tsao, C.

    2010-12-01

    The rapid growth of modern biofuels production (primarily ethanol) contributes to increased black carbon and co-pollutant emissions, particularly due to the field burning of agriculture wastes and the indirect land use impacts of forest clearing. U.S. bioenergy policy has already mandated life-cycle emissions thresholds for greenhouse gases from biofuels but there is still a need to incorporate black carbon and other short-lived climate forcers into these metrics. Thus, an understanding of the biofuels sector for black carbon and co-pollutant emissions and impacts remains a critical knowledge gap. Here we combine high-resolution agronomic data and regional chemical transport modeling to consider the life-cycle emissions of black carbon from sugarcane ethanol production in Brazil. Furthermore, we explore the potential for significant radiative forcing from the pre-harvest burning of sugarcane fields and the indirect land use emissions associated with deforestation.

  14. Stability of black carbon in soils across a climatic gradient

    SciTech Connect

    Cheng, Chih-hsin; Lehmann, Johannes C.; Thies, Janice E.; Burton, Sarah D.

    2008-06-04

    The recalcitrant properties of black carbon (BC) grant it to be a significant pool of stable C in soils. Up to now, however, the longevity of BC under different climates is still unclear. In this study, we used BC samples from historical charcoal blast furnace sites to examine the stability of BC across a climatic gradient of mean annual temperatures (MAT) from 3.9 to 17.2ºC. The results showed that C concentration and C storage in the BC-containing soils at a soil depth of 0 - 0.2 m were 9.0 and 4.7 times higher than those in adjacent soils, respectively. Carbon in the BC-containing soils was more stable, with a significantly lower amount of labile C fraction (4.4 mg g C-1 vs. 27.5 mg g C-1) and longer half-life of the recalcitrant C fraction (59 years vs. 9 years) than the adjacent soils determined from incubation experiments. The stability of BC was primarily due to its inherently recalcitrant chemical composition as suggested by short-term incubation and solid state 13C nuclear magnetic resonance spectra of isolated BC particles. A significant negative relationship between C storage and MAT (-0.62; P<0.01) further indicated that C storage was decreased with warmer climate. However, the lack of a relationship between MAT and BC mineralization (P>0.05) suggested that the stability of the remaining BC was similar between sites with very different MAT. Despite the fact that warming or cooling result in immediate consequences for BC stocks, it may have little impact on the stability of the remaining BC over the period studied.

  15. Black carbon reduction will weaken the aerosol net cooling effect

    NASA Astrophysics Data System (ADS)

    Wang, Z. L.; Zhang, H.; Zhang, X. Y.

    2014-12-01

    Black carbon (BC), a distinct type of carbonaceous material formed from the incomplete combustion of fossil and biomass based fuels under certain conditions, can interact with solar radiation and clouds through its strong light-absorption ability, thereby warming the Earth's climate system. Some studies have even suggested that global warming could be slowed down in a short term by eliminating BC emission due to its short lifetime. In this study, we estimate the influence of removing some sources of BC and other co-emitted species on the aerosol radiative effect by using an aerosol-climate coupled model BCC_AGCM2.0.1_CUACE/Aero, in combination with the aerosol emissions from the Representative Concentration Pathways (RCPs) scenarios. We find that the global annual mean aerosol net cooling effect at the top of the atmosphere (TOA) will be enhanced by 0.12 W m-2 compared with present-day conditions if the BC emission is reduced exclusively to the level projected for 2100 based on the RCP2.6 scenario. This will be beneficial for the mitigation of global warming. However, the global annual mean aerosol net cooling effect at the TOA will be weakened by 1.7-2.0 W m-2 relative to present-day conditions if emissions of BC and co-emitted sulfur dioxide and organic carbon are simultaneously reduced as the most close conditions to the actual situation to the level projected for 2100 in different ways based on the RCP2.6, RCP4.5, and RCP8.5 scenarios. Because there are no effective ways to remove the BC exclusively without influencing the other co-emitted components, our results therefore indicate that a reduction in BC emission can lead to an unexpected warming on the Earth's climate system in the future.

  16. Children exposure assessment to ultrafine particles and black carbon: The role of transport and cooking activities

    NASA Astrophysics Data System (ADS)

    Buonanno, G.; Stabile, L.; Morawska, L.; Russi, A.

    2013-11-01

    An accurate evaluation of the airborne particle dose-response relationship requires detailed measurements of the actual particle concentration levels that people are exposed to, in every microenvironment in which they reside. The aim of this work was to perform an exposure assessment of children in relation to two different aerosol species: ultrafine particles (UFPs) and black carbon (BC). To this purpose, personal exposure measurements, in terms of UFP and BC concentrations, were performed on 103 children aged 8-11 years (10.1 ± 1.1 years) using hand-held particle counters and aethalometers. Simultaneously, a time-activity diary and a portable GPS were used to determine the children's daily time-activity pattern and estimate their inhaled dose of UFPs and BC. The median concentration to which the study population was exposed was found to be comparable to the high levels typically detected in urban traffic microenvironments, in terms of both particle number (2.2 × 104 part. cm-3) and BC (3.8 μg m-3) concentrations. Daily inhaled doses were also found to be relatively high and were equal to 3.35 × 1011 part. day-1 and 3.92 × 101 μg day-1 for UFPs and BC, respectively. Cooking and using transportation were recognized as the main activities contributing to overall daily exposure, when normalized according to their corresponding time contribution for UFPs and BC, respectively. Therefore, UFPs and BC could represent tracers of children exposure to particulate pollution from indoor cooking activities and transportation microenvironments, respectively.

  17. Black carbon measurement in a coastal area of south China

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Lee, S. C.; Ho, K. F.; Wang, Y. Q.; Cao, J. J.; Chow, J. C.; Watson, J. G.

    2006-06-01

    To better understand anthropogenic pollution originating in Asia and its transport into the global atmosphere, black carbon (BC) emissions were measured continuously from June 2004 to May 2005 at Hok Tsui (22.13°N, 114.15°E). Hok Tsui is a continental outflow, downwind monitoring site, located in a coastal area near Hong Kong. Using an Aethalometer, hourly BC concentrations ranged from 63.0 ng/m3 to 17.3 μg/m3, showing a clear seasonal pattern with high concentrations in winter, spring, and fall and low values in summer. During the winter, high BC concentrations occurred frequently as a result of southward long-range transport of polluted air masses in the boundary layer over the Asian continent. Anthropogenic emissions in coastal areas of southeastern China were the major potential sources for the observed pollutants. During the summer, high BC concentrations were measured occasionally when the air masses came from the northwest. These anthropogenic pollutants were found to be regional in nature, originating from sources in the Pearl River Delta (PRD) region, which included emissions from residential and agricultural combustion, industry, power plants, motor vehicles, and ships.

  18. Black carbon aerosols and the third polar ice cap

    SciTech Connect

    Menon, Surabi; Koch, Dorothy; Beig, Gufran; Sahu, Saroj; Fasullo, John; Orlikowski, Daniel

    2010-04-15

    Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region) have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC) aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by {approx}0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is {approx}36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000), and are mainly obtained with the newer BC estimates.

  19. Inhalation of Carbon Black Nanoparticles Aggravates Pulmonary Inflammation in Mice

    PubMed Central

    Saputra, Devina; Yoon, Jin-ha; Park, Hyunju; Heo, Yongju; Yang, Hyoseon; Lee, Eun Ji; Lee, Sangjin; Song, Chang-Woo; Lee, Kyuhong

    2014-01-01

    An increasing number of recent studies have focused on the impact of particulate matter on human health. As a model for atmospheric particulate inhalation, we investigated the effects of inhaled carbon black nanoparticles (CBNP) on mice with bleomycin-induced pulmonary fibrosis. The CNBPs were generated by a novel aerosolization process, and the mice were exposed to the aerosol for 4 hours. We found that CBNP inhalation exacerbated lung inflammation, as evidenced by histopathology analysis and by the expression levels of interleukin-6 protein, fibronectin, and interferon-γ mRNAs in lung tissues. Notably, fibronectin mRNA expression showed a statistically significant increase in expression after CBNP exposure. These data suggest that the concentration of CBNPs delivered (calculated to be 12.5 μg/m3) can aggravate lung inflammation in mice. Our results also suggest that the inhalation of ultrafine particles like PM 2.5 is an impactful environmental risk factor for humans, particularly in susceptible populations with predisposing lung conditions. PMID:25071917

  20. Trend in global black carbon emissions from 1960 to 2007.

    PubMed

    Wang, Rong; Tao, Shu; Shen, Huizhong; Huang, Ye; Chen, Han; Balkanski, Yves; Boucher, Olivier; Ciais, Philippe; Shen, Guofeng; Li, Wei; Zhang, Yanyan; Chen, Yuanchen; Lin, Nan; Su, Shu; Li, Bengang; Liu, Junfeng; Liu, Wenxin

    2014-06-17

    Black carbon (BC) plays an important role in both climate change and health impact. Still, BC emissions as well as the historical trends are associated with high uncertainties in existing inventories. In the present study, global BC emissions from 1960 to 2007 were estimated for 64 sources, by using recompiled fuel consumption and emission factor data sets. Annual BC emissions had increased from 5.3 (3.4-8.5 as an interquartile range) to 9.1 (5.6-14.4) teragrams during this period. Our estimations are 11-16% higher than those in previous inventories. Over the period, we found that the BC emission intensity, defined as the amount of BC emitted per unit of energy production, had decreased for all the regions, especially China and India. Improvements in combustion technology and changes in fuel composition had led to an increase in energy use efficiency, and subsequently a decline of BC emission intensities in power plants, the residential sector, and transportation. On the other hand, the BC emission intensities had increased in the industrial and agricultural sectors, mainly due to an expansion of low-efficiency industry (coke and brick production) in developing countries and to an increasing usage of diesel in agriculture in developed countries. PMID:24825392

  1. Characterization of the interactions between protein and carbon black.

    PubMed

    Chen, Tzu-Tao; Chuang, Kai-Jen; Chiang, Ling-Ling; Chen, Chun-Chao; Yeh, Chi-Tai; Wang, Liang-Shun; Gregory, Clive; Jones, Tim; BéruBé, Kelly; Lee, Chun-Nin; Chuang, Hsiao-Chi; Cheng, Tsun-Jen

    2014-01-15

    A considerable amount of studies have been conducted to investigate the interactions of biological fluids with nanoparticle surfaces, which exhibit a high affinity for proteins and particles. However, the mechanisms underlying these interactions have not been elucidated, particularly as they relate to human health. Using bovine serum albumin (BSA) and mice bronchoalveolar lavage fluid (BALF) as models for protein-particle conjugates, we characterized the physicochemical modifications of carbon blacks (CB) with 23nm or 65nm in diameter after protein treatment. Adsorbed BALF-containing proteins were quantified and identified by pathways, biological analyses and protein classification. Significant modifications of the physicochemistry of CB were induced by the addition of BSA. Enzyme modulators and hydrolase predominately interacted with CB, with protein-to-CB interactions that were associated with the coagulation pathways. Additionally, our results revealed that an acute-phase response could be activated by these proteins. With regard to human health, the present study revealed that the CB can react with proteins (∼55kDa and 70kDa) after inhalation and may modify the functional structures of lung proteins, leading to the activation of acute-inflammatory responses in the lungs. PMID:24291665

  2. Global Civil Aviation Black Carbon Particle Mass and Number Emissions

    NASA Astrophysics Data System (ADS)

    Stettler, M. E. J.

    2015-12-01

    Black carbon (BC) is a product of incomplete combustion emitted by aircraft engines. In the atmosphere, BC particles strongly absorb incoming solar radiation and influence cloud formation processes leading to highly uncertain, but likely net positive warming of the earth's atmosphere. At cruise altitude, BC particle number emissions can influence the concentration of ice nuclei that can lead to contrail formation, with significant and highly uncertainty climate impacts. BC particles emitted by aircraft engines also degrade air quality in the vicinity of airports and globally. A significant contribution to the uncertainty in environmental impacts of aviation BC emissions is the uncertainty in emissions inventories. Previous work has shown that global aviation BC mass emissions are likely to have been underestimated by a factor of three. In this study, we present an updated global BC particle number inventory and evaluate parameters that contribute to uncertainty using global sensitivity analysis techniques. The method of calculating particle number from mass utilises a description of the mobility of fractal aggregates and uses the geometric mean diameter, geometric standard deviation, mass-mobility exponent, primary particle diameter and material density to relate the particle number concentration to the total mass concentration. Model results show good agreement with existing measurements of aircraft BC emissions at ground level and at cruise altitude. It is hoped that the results of this study can be applied to estimate direct and indirect climate impacts of aviation BC emissions in future studies.

  3. Large historical changes of fossil-fuel black carbon aerosols

    SciTech Connect

    Novakov, T.; Ramanathan, V.; Hansen, J.E.; Kirchstetter, T.W.; Sato, M.; Sinton, J.E.; Sathaye, J.A.

    2002-09-26

    Anthropogenic emissions of fine black carbon (BC) particles, the principal light-absorbing atmospheric aerosol, have varied during the past century in response to changes of fossil-fuel utilization, technology developments, and emission controls. We estimate historical trends of fossil-fuel BC emissions in six regions that represent about two-thirds of present day emissions and extrapolate these to global emissions from 1875 onward. Qualitative features in these trends show rapid increase in the latter part of the 1800s, the leveling off in the first half of the 1900s, and the re-acceleration in the past 50 years as China and India developed. We find that historical changes of fuel utilization have caused large temporal change in aerosol absorption, and thus substantial change of aerosol single scatter albedo in some regions, which suggests that BC may have contributed to global temperature changes in the past century. This implies that the BC history needs to be represented realistically in climate change assessments.

  4. Radiative forcing of black carbon over eastern India

    NASA Astrophysics Data System (ADS)

    Sreekanth, V.; Niranjan, K.; Madhavan, B. L.

    2007-09-01

    Measurements of aerosol Black Carbon using a 7 channel Aethalometer at Visakhapatnam, a coastal tropical station on the east coast of India are used to study the temporal variation of surface BC mass concentration. The surface BC mass concentrations show a significant diurnal variation which is seasonally dependant. Analysis using the multi spectral data indicates that the BC mass does not show significant absorption due to non-BC aerosol species which indicates that the surface BC mass is dominated by fossil fuel sources with no indication of any other strong anthropogenic source. The Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model was used in conjunction with Optical Properties of Aerosols and Clouds (OPAC) to estimate the BC radiative forcing. The results show large negative surface forcing during winter (-35.78 W/m2), moderate during summer (-16.8 W/m2) and lower forcing during monsoon (-9.9 W/m2) and post monsoon (-2.81 W/m2). The forcing at the top of the atmosphere is positive for all the seasons.

  5. Black carbon radiative forcing over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    He, Cenlin; Li, Qinbin; Liou, Kuo-Nan; Takano, Yoshi; Gu, Yu; Qi, Ling; Mao, Yuhao; Leung, L. Ruby

    2014-11-01

    We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. The annual mean BC snow albedo forcing is 2.9 W m-2 averaged over snow-covered plateau regions, which is a factor of 3 larger than the value over global land snowpack. BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing, and coated BC increases the forcing by 30-50% compared with uncoated BC aggregates, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. The annual BC DRF at the top of the atmosphere is 2.3 W m-2 with uncertainties of -70-85% in the plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network observations. The BC forcings are attributed to emissions from different regions.

  6. Black carbon emissions in China from 1949 to 2050.

    PubMed

    Wang, Rong; Tao, Shu; Wang, Wentao; Liu, Junfeng; Shen, Huizhong; Shen, Guofeng; Wang, Bin; Liu, Xiaopeng; Li, Wei; Huang, Ye; Zhang, Yanyan; Lu, Yan; Chen, Han; Chen, Yuanchen; Wang, Chen; Zhu, Dan; Wang, Xilong; Li, Bengang; Liu, Wenxin; Ma, Jianmin

    2012-07-17

    Black carbon (BC) emissions from China are of global concern. A new BC emission inventory (PKU-BC(China)) has been developed with the following improvements: (1) The emission factor database was updated; (2) a 0.1° × 0.1° gridded map was produced for 2007 based on county-level proxies; (3) time trends were derived for 1949-2007 and predicted for 2008-2050; and (4) the uncertainties associated with the inventory were quantified. It was estimated that 1957 Gg of BC were emitted in China in 2007, which is greater than previously reported. Residential coal combustion was the largest source, followed by residential biofuel burning, coke production, diesel vehicles, and brick kilns. By using a county-level disaggregation method, spatial bias in province-level disaggregation, mainly due to uneven per capita emissions within provinces, was reduced by 42.5%. Emissions increased steadily since 1949 until leveling off in the mid-1990s, due to a series of technological advances and to socioeconomic progress. BC emissions in China in 2050 are predicted to be 920-2183 Gg/yr under various scenarios; and the industrial and transportation sectors stand to benefit the most from technological improvements. PMID:22730898

  7. Black carbon aerosol-induced Northern Hemisphere tropical expansion

    SciTech Connect

    Kovilakam, Mahesh; Mahajan, Salil

    2015-06-23

    Global climate models (GCMs) underestimate the observed trend in tropical expansion. Recent studies partly attribute it to black carbon (BC) aerosols, which are poorly represented in GCMs. In this paper, we conduct a suite of idealized experiments with the Community Atmosphere Model version 4 coupled to a slab ocean model forced with increasing BC concentrations covering a large swath of the estimated range of current BC radiative forcing while maintaining their spatial distribution. The Northern Hemisphere (NH) tropics expand poleward nearly linearly as BC radiative forcing increases (0.7° W-1 m2), indicating that a realistic representation of BC could reduce GCM biases. We find support for the mechanism where BC-induced midlatitude tropospheric heating shifts the maximum meridional tropospheric temperature gradient poleward resulting in tropical expansion. Finally, we also find that the NH poleward tropical edge is nearly linearly correlated with the location of the Intertropical Convergence Zone, which shifts northward in response to increasing BC.

  8. Black carbon aerosol-induced Northern Hemisphere tropical expansion

    DOE PAGESBeta

    Kovilakam, Mahesh; Mahajan, Salil

    2015-06-23

    Global climate models (GCMs) underestimate the observed trend in tropical expansion. Recent studies partly attribute it to black carbon (BC) aerosols, which are poorly represented in GCMs. In this paper, we conduct a suite of idealized experiments with the Community Atmosphere Model version 4 coupled to a slab ocean model forced with increasing BC concentrations covering a large swath of the estimated range of current BC radiative forcing while maintaining their spatial distribution. The Northern Hemisphere (NH) tropics expand poleward nearly linearly as BC radiative forcing increases (0.7° W-1 m2), indicating that a realistic representation of BC could reduce GCMmore » biases. We find support for the mechanism where BC-induced midlatitude tropospheric heating shifts the maximum meridional tropospheric temperature gradient poleward resulting in tropical expansion. Finally, we also find that the NH poleward tropical edge is nearly linearly correlated with the location of the Intertropical Convergence Zone, which shifts northward in response to increasing BC.« less

  9. Assessing the climatic benefits of black carbon mitigation

    PubMed Central

    Kopp, Robert E.; Mauzerall, Denise L.

    2010-01-01

    To limit mean global warming to 2 °C, a goal supported by more than 100 countries, it will likely be necessary to reduce emissions not only of greenhouse gases but also of air pollutants with high radiative forcing (RF), particularly black carbon (BC). Although several recent research papers have attempted to quantify the effects of BC on climate, not all these analyses have incorporated all the mechanisms that contribute to its RF (including the effects of BC on cloud albedo, cloud coverage, and snow and ice albedo, and the optical consequences of aerosol mixing) and have reported their results in different units and with different ranges of uncertainty. Here we attempt to reconcile their results and present them in uniform units that include the same forcing factors. We use the best estimate of effective RF obtained from these results to analyze the benefits of mitigating BC emissions for achieving a specific equilibrium temperature target. For a 500 ppm CO2e (3.1 W m-2) effective RF target in 2100, which would offer about a 50% chance of limiting equilibrium warming to 2.5 °C above preindustrial temperatures, we estimate that failing to reduce carbonaceous aerosol emissions from contained combustion would require CO2 emission cuts about 8 years (range of 1–15 years) earlier than would be necessary with full mitigation of these emissions. PMID:20566891

  10. Factors controlling seasonal variations in Arctic black carbon

    NASA Astrophysics Data System (ADS)

    Shen, Z.; Ming, Y.; Horowitz, L. W.

    2015-12-01

    Arctic haze has a distinct seasonality with higher concentrations in winter and spring. This study evaluates how different processes of large-scale circulation and removal control seasonal variations in Arctic black carbon (BC) using the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric general circulation model (AM3). We find that transport and wet deposition play unequal roles in determining Arctic BC seasonal cycle. Despite seasonal differences in general circulation patterns, the eddy-driven BC transport changes little throughout the year, and the seasonal cycle of Arctic BC is attributed to wet removal. BC hydrophilic fraction affected by the aging process and hydrophilic BC (BCpi) wet deposition rate affected by cloud microphysics determine wet deposition. Both low hydrophilic fraction and low wet deposition rate account for the peak of BC in winter. The transition to low BC in summer results from an increase in wet deposition rate, while the return of BC in late autumn is mainly caused by a sharp decrease in hydrophilic fraction. The results suggest that the concentrations of Arctic aerosols as well as their climate impacts may be susceptible to modification in a future climate.

  11. Black Carbon Radiative Forcing over the Tibetan Plateau

    SciTech Connect

    He, Cenlin; Li, Qinbin; Liou, K. N.; Takano, Y.; Gu, Yu; Qi, L.; Mao, Yuhao; Leung, Lai-Yung R.

    2014-11-28

    We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. Our best estimate of the annual BC snow albedo forcing in the Plateau is 2.9 W m-2 (uncertainty: 1.5–5.0 W m-226 ). We find that BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing and coated BC increases the forcing by 30-50% compared with uncoated BC, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. Our best estimate of the annual BC DRF at the top of the atmosphere is 2.3 W m-2 (uncertainty: 0.7–4.3 W m-230 ) in the Plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network (AERONET) observations. The BC forcings are attributed to emissions from different regions.

  12. Daily personal exposure to black carbon: A pilot study

    NASA Astrophysics Data System (ADS)

    Williams, Ryan D.; Knibbs, Luke D.

    2016-05-01

    Continuous personal monitoring is the benchmark for air pollution exposure assessment. Black carbon (BC) is a strong marker of primary combustion like vehicle and biomass emissions. There have been few studies that quantified daily personal BC exposure and the contribution that different microenvironments make to it. In this pilot study, we used a portable aethalometer to measure BC concentrations in an individual's breathing zone at 30-s intervals while he performed his usual daily activities. We used a GPS and time-activity diary to track where he spent his time. We performed twenty 24-h measurements, and observed an arithmetic mean daily exposure concentration of 603 ng/m3. We estimated that changing commute modes from bus to train reduced the 24-h mean BC exposure concentration by 29%. Switching from open windows to closed windows and recirculated air in a car led to a reduction of 32%. Living in a home without a wood-fired heater caused a reduction of 50% compared with a wood-heated home. Our preliminary findings highlight the potential utility of simple approaches to reduce a person's daily BC exposure.

  13. Radiative absorption enhancement from coatings on black carbon aerosols.

    PubMed

    Cui, Xinjuan; Wang, Xinfeng; Yang, Lingxiao; Chen, Bing; Chen, Jianmin; Andersson, August; Gustafsson, Örjan

    2016-05-01

    The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols. The mass absorption cross-section (MAC) of decoated/pure atmospheric BC aerosols of 4.4±0.8m(2)g(-1) was enhanced to 9.6±1.8m(2)g(-1) at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (EMAC) rises from 1.4±0.3 in fresh combustion emissions to ~3 for aged ambient China aerosols. The three-week high-intensity campaign observed an average EMAC of 2.25±0.55, and sulfates were primary drivers of the enhanced BC absorption. PMID:26874760

  14. Daily personal exposure to black carbon: A pilot study

    NASA Astrophysics Data System (ADS)

    Williams, Ryan D.; Knibbs, Luke D.

    2016-05-01

    Continuous personal monitoring is the benchmark for air pollution exposure assessment. Black carbon (BC) is a strong marker of primary combustion like vehicle and biomass emissions. There have been few studies that quantified daily personal BC exposure and the contribution that different microenvironments make to it. In this pilot study, we used a portable aethalometer to measure BC concentrations in an individual's breathing zone at 30-s intervals while he performed his usual daily activities. We used a GPS and time-activity diary to track where he spent his time. We performed twenty 24-h measurements, and observed an arithmetic mean daily exposure concentration of 603 ng/m3. We estimated that changing commute modes from bus to train reduced the 24-h mean BC exposure concentration by 29%. Switching from open windows to closed windows and recirculated air in a car led to a reduction of 32%. Living in a home without a wood-fired heater caused a reduction of 50% compared with a wood-heated home. Our preliminary findings highlight the potential utility of simple approaches to reduce a person's daily BC exposure.

  15. Organic Carbon--water Concentration Quotients (IIsocS and [pi]pocS): Measuring Apparent Chemical Disequilibria and Exploring the Impact of Black Carbon in Lake Michigan

    EPA Science Inventory

    When black carbon (bc) and biologically derived organic carbon (bioc) phases are present in sediments or suspended particulates, both forms of carbon act additively to sorb organic chemicals but the bc phase has more sorption capacity per unit mass. . . .

  16. Factorial Based Response Surface Modeling with Confidence Intervals for Optimizing Thermal Optical Transmission Analysis of Atmospheric Black Carbon

    EPA Science Inventory

    We demonstrate how thermal-optical transmission analysis (TOT) for refractory light-absorbing carbon in atmospheric particulate matter was optimized with empirical response surface modeling. TOT employs pyrolysis to distinguish the mass of black carbon (BC) from organic carbon (...

  17. Environmental hazards and distribution of radioactive black sand along the Rosetta coastal zone in Egypt using airborne spectrometric and remote sensing data.

    PubMed

    Kaiser, M F; Aziz, A M; Ghieth, B M

    2014-11-01

    High-resolution airborne gamma ray spectrometry, conducted in 2003, was used to estimate radioactive elements spatial abundance along the Rosetta coastal zone area. It was noticed that both Uranium and Thorium are concentrated in the black sand deposits along the beach. In contrary, Potassium was observed in high level abundance at the cultivated Nile Delta lands due to the accumulated usage of fertilizers. Exposure Rate (ER), Absorbed Dose Rate (ADR) and Annual Effective Dose Rate (AEDR) were calculated to evaluate the radiation background influence in human. Results indicated that the human body in the study sites is subjected to radiation hazards exceeds the accepted limit for long duration exposure. In addition, the areas covered by the highest concentration of Uranium and Thorium show the highest level of radiogenic heat production. Detection the environmental hazards of the radioactive black sands in the study site encouraged this research to monitor the spatial and temporal distribution of these sediments. The Landsat Thematic Mapper images acquired in 1990, 2003 and 2013 were analyzed using remote sensing image processing techniques. Image enhancements, classification and changes detection indicated a positive significant relationship between the patterns of coastline changes and distribution of the radioactive black sand in the study sites. The radioactive black sands are usually concentrated in the eroded areas. Therefore, in 1990 high concentration of the radioactive black sands were observed along the eastern and western flanks of the Rosetta promontory. Distribution of these sediments decreased due to the construction of the protective sea walls. Most of the radioactive black sands are transported toward the east in Abu Khashaba bay under the effect of the longshore currents and toward the west in Alexandria and Abu Quir bay under the action of the seasonal reverse currents. PMID:25011074

  18. Selection and Characterization of Carbon Black and Surfactants for Development of Small Scale Uranium Oxicarbide Kernels

    SciTech Connect

    Contescu, Cristian I

    2006-01-01

    This report supports the effort for development of small scale fabrication of UCO (a mixture of UO{sub 2} and UC{sub 2}) fuel kernels for the generation IV high temperature gas reactor program. In particular, it is focused on optimization of dispersion conditions of carbon black in the broths from which carbon-containing (UO{sub 2} {center_dot} H{sub 2}O + C) gel spheres are prepared by internal gelation. The broth results from mixing a hexamethylenetetramine (HMTA) and urea solution with an acid-deficient uranyl nitrate (ADUN) solution. Carbon black, which is previously added to one or other of the components, must stay dispersed during gelation. The report provides a detailed description of characterization efforts and results, aimed at identification and testing carbon black and surfactant combinations that would produce stable dispersions, with carbon particle sizes below 1 {micro}m, in aqueous HMTA/urea and ADUN solutions. A battery of characterization methods was used to identify the properties affecting the water dispersability of carbon blacks, such as surface area, aggregate morphology, volatile content, and, most importantly, surface chemistry. The report introduces the basic principles for each physical or chemical method of carbon black characterization, lists the results obtained, and underlines cross-correlations between methods. Particular attention is given to a newly developed method for characterization of surface chemical groups on carbons in terms of their acid-base properties (pK{sub a} spectra) based on potentiometric titration. Fourier-transform infrared (FTIR) spectroscopy was used to confirm the identity of surfactants, both ionic and non-ionic. In addition, background information on carbon black properties and the mechanism by which surfactants disperse carbon black in water is also provided. A list of main physical and chemical properties characterized, samples analyzed, and results obtained, as well as information on the desired trend or

  19. Empirical correlations between black carbon aerosol and carbon monoxide in the lower and middle troposphere

    NASA Astrophysics Data System (ADS)

    Spackman, J. R.; Schwarz, J. P.; Gao, R. S.; Watts, L. A.; Thomson, D. S.; Fahey, D. W.; Holloway, J. S.; de Gouw, J. A.; Trainer, M.; Ryerson, T. B.

    2008-10-01

    Single-particle measurements of black carbon (BC) aerosol and simultaneous measurements of carbon monoxide (CO) were acquired aboard the NOAA WP-3D aircraft during the 2006 Texas Air Quality Study (TexAQS). Observed average BC mass loadings, estimated to account for ~90% of the ambient BC mass, decreased by more than 2 orders of magnitude from the polluted boundary layer to the clean middle troposphere (6 km). A strong positive, but non-linear, correlation was observed between simultaneous measurements of BC and CO. Based on an analysis of all the data below 1 km, we report a compact relationship between BC and CO with a slope of 5.8 +/- 1.0 ng BC (kg dry air)-1 (ppb CO)-1 that is representative of regional urban and industrial emissions from Houston and Dallas. The BC/CO emission ratio for a fresh biomass-burning plume was estimated at 9 +/- 2 ng kg-1 ppb-1.

  20. Latitudinal distribution of black carbon soot in the upper troposphere and lower stratosphere

    NASA Technical Reports Server (NTRS)

    Blake, David F.; Kato, Katharine

    1995-01-01

    Black carbon soot from the upper troposphere and lower stratosphere has been systematically collected at latitudes from 90 deg N to 45 deg S. The measured latitudinal distribution of this soot at 10 to 11 km altitude is found to covary with commercial air traffic fuel use, suggesting that aircraft fuel combustion at altitude is the principal source. In addition, at latitudes where the commercial air traffic is high, measured black carbon soot values are high even at 20 km altitude, suggesting that aircraft-generated soot injected just above the tropopause may be transported to higher altitudes. During the volcanically influenced period in which these samples were collected, the number abundances, total mass, and calculated total surface area of black carbon soot are 2-3 orders of magnitude lower than similar measures of sulfuric acid aerosol. During volcanically quiescent periods, the calculated total surface area of black carbon soot aerosol is of the same order of magnitude as that of the background sulfuric acid aerosol. It appears from this comparison that black carbon soot is only capable of influencing lower stratosphere or upper troposphere chemistry during periods when the aerosol budget is not dominated by volcanic activity. It remains to determine the extent to which black carbon soot particles act as nuclei for sulfuric acid aerosol formation. However, mass balance calculations suggest that aircraft soot injected at altitude does not represent a significant source of condensation nuclei for sulfuric acid aerosols.

  1. Latitudinal distribution of black carbon soot in the upper troposphere and lower stratosphere

    SciTech Connect

    Blake, D.F.; Kato, K.

    1995-04-20

    Black carbon soot from the upper troposphere and lower stratosphere has been systematically collected at latitudes from 90{degrees}N to 45{degrees}S. The measured latitudinal distribution of this soot at 10- to 11-km altitude is found to covary with commercial air traffic fuel use, suggesting that aircraft fuel combustion at altitude is the principal source. In addition, at latitudes where the commercial air traffic is high, measured black carbon soot values are high even at 20-km altitude, suggesting that aircraft-generated soot injected just above the tropopause may be transported to higher altitudes. During the volcanically influenced period in which these samples were collected, the number abundances, total mass, and calculated total surface area of black carbon soot are 2-3 orders of magnitude lower than similar measures of sulfuric acid aerosol. During volcanically quiescent periods, the calculated total surface area of black carbon soot aerosol is of the same order of magnitude as that of the background sulfuric acid aerosol. It appears from this comparison that black carbon soot is only capable of influencing lower stratosphere or upper troposphere chemistry during periods when the aerosol budget is not dominated by volcanic activity. It remains to determine the extent to which black carbon soot particles act as nuclei for sulfuric acid aerosol formation. However, mass balance calculations suggest that aircraft soot injected at altitude does not represent a significant source of condensation nuclei for sulfuric acid aerosols. 29 refs., 2 figs., 2 tabs.

  2. Measurement of Black Carbon and Co-pollutants Emitted from Diesel Vehicles in Mexico

    NASA Astrophysics Data System (ADS)

    Zavala, M. A.; Molina, L. T.; Fortner, E.; Herndon, S.; Knighton, B.; Yacovitch, T. I.; Floerchinger, C. R.; Roscioli, J. R.; Kolb, C. E.; Paramo, V. H.; Zirath, S.; Mejia, J.; Jazcilevich, A. D.

    2013-12-01

    Freight, public transport, and heavy-duty trucks can contribute to harmful emissions of black carbon and other co-pollutants in many urban areas. Controlling the emissions of black carbon from the transport sector is important for the potential of mitigating its impacts on climate, ecosystems, and human health. However, reducing the emissions of black carbon from mobile sources is be a challenging task in many developing urban areas due to economic, social, and technical constrains, as well as the uncertainties surrounding the accurate quantification of the associated benefits. Several emissions control technologies offer a proven approach for reducing emissions of black carbon from diesel-powered mobile sources, but the accurate quantification of associated emissions benefits in developing urban areas is not well documented. We present the results of the measurement of black carbon and co-emitted pollutants of dozens of diesel powered vehicles, including freight trucks, public transport buses, and intra-city metrobuses sampled during a 4-day experiment in Mexico City in February of 2013 as part of the SLCFs-Mexico project. Measurements were obtained with the Aerodyne Mobile Laboratory, remote sensing, and portable emissions measurements, and encompassed the sampling of several vehicle models and technologies in experimental and real-world driving conditions. The results can help in the identification of key factors that hinder the implementation of control emissions for reducing emissions of black carbon elsewhere and the potential benefits of implementing various emission control technologies.

  3. Challenges for Reducing Emissions of Black Carbon from the Transport Sector in Urban Areas

    NASA Astrophysics Data System (ADS)

    Zavala, M. A.; Molina, L. T.

    2013-05-01

    The transport sector is a large contributor of harmful gaseous and particulate emissions in many urban areas. Black carbon is a component of short-lived particulate matter emitted predominantly by freight, public transport, and heavy- duty trucks. Controlling the emissions of black carbon from the transport sector is important for mitigating its impacts on climate, ecosystems, and human health. However, reducing the emissions of black carbon from mobile sources may be a challenging task in many developing urban areas due to economic, social, and technical constrains. Several emissions control technologies offer a proven approach for reducing emissions of black carbon from diesel-powered mobile sources, but the accurate quantification of associated emissions benefits in developing urban areas is not well documented. We describe recent advances for the estimation of black carbon emissions from the transport sector in real world driving conditions and present examples of the potential benefits of implementing various emission control technologies in Mexico. The results can help in the identification of key factors that hinder the implementation of control emissions for reducing emissions of black carbon elsewhere.

  4. Effects of Black Carbon on Climate: Advances in Measurement and Modeling

    NASA Astrophysics Data System (ADS)

    Kondo, Y.

    2015-04-01

    Black carbon (BC) particles are non-spherical agglomerates consisting of hundreds or thousands of graphitic carbon spherules the diameters of which are about 15-50 nm. The spherules are graphitic in their molecular states and are, thus, strongly light-absorbing. BC particles are emitted by the incomplete combustion of carbon-based fossil fuels and biomass. BC mass in the atmosphere resides in agglomerates typically between 100 and 600 nm in diameter. They influence the global radiation budget by strongly absorbing solar radiation in the visible wavelengths and by changing the albedo of snow through deposition. Radiative forcing (RF) of BC is defined as the change in net radiative flux at the top of the atmosphere in W m-2 due to a change of BC between the pre-industrial time and present-day periods. The instantaneous direct radiative forcing of airborne BC particles (BC DRF), which does not include climate feedbacks, is determined by their absorption cross sections and spatial distributions. The distributions of BC are, in turn, controlled by its emission, dynamical transport, and loss during transport. The absorption cross section of BC is controlled by its optical properties (i.e., refractive index) and microphysical properties (size distribution, morphology, and mixing state). Because it is crucial to characterize these parameters, we first developed techniques to measure them accurately. Newly-developed BC measurement technologies constitute the firm basis of our studies. The techniques were applied to laboratory experiments and field observations of BC particles in air and rainwater. We also developed regional scale three-dimensional (3D) models to quantitatively interpret the observational results. One of the models calculates BC aging and optical/radiative processes explicitly without parameterizations. The reliable field measurements and model calculations of BC has enabled an improved understanding of the physical and chemical processes that control the

  5. Modelling above-ground carbon dynamics using multi-temporal airborne lidar: insights from a Mediterranean woodland

    NASA Astrophysics Data System (ADS)

    Simonson, W.; Ruiz-Benito, P.; Valladares, F.; Coomes, D.

    2016-02-01

    Woodlands represent highly significant carbon sinks globally, though could lose this function under future climatic change. Effective large-scale monitoring of these woodlands has a critical role to play in mitigating for, and adapting to, climate change. Mediterranean woodlands have low carbon densities, but represent important global carbon stocks due to their extensiveness and are particularly vulnerable because the region is predicted to become much hotter and drier over the coming century. Airborne lidar is already recognized as an excellent approach for high-fidelity carbon mapping, but few studies have used multi-temporal lidar surveys to measure carbon fluxes in forests and none have worked with Mediterranean woodlands. We use a multi-temporal (5-year interval) airborne lidar data set for a region of central Spain to estimate above-ground biomass (AGB) and carbon dynamics in typical mixed broadleaved and/or coniferous Mediterranean woodlands. Field calibration of the lidar data enabled the generation of grid-based maps of AGB for 2006 and 2011, and the resulting AGB change was estimated. There was a close agreement between the lidar-based AGB growth estimate (1.22 Mg ha-1 yr-1) and those derived from two independent sources: the Spanish National Forest Inventory, and a tree-ring based analysis (1.19 and 1.13 Mg ha-1 yr-1, respectively). We parameterised a simple simulator of forest dynamics using the lidar carbon flux measurements, and used it to explore four scenarios of fire occurrence. Under undisturbed conditions (no fire) an accelerating accumulation of biomass and carbon is evident over the next 100 years with an average carbon sequestration rate of 1.95 Mg C ha-1 yr-1. This rate reduces by almost a third when fire probability is increased to 0.01 (fire return rate of 100 years), as has been predicted under climate change. Our work shows the power of multi-temporal lidar surveying to map woodland carbon fluxes and provide parameters for carbon

  6. Modelling above-ground carbon dynamics using multi-temporal airborne lidar: insights from a Mediterranean woodland

    NASA Astrophysics Data System (ADS)

    Simonson, W.; Ruiz-Benito, P.; Valladares, F.; Coomes, D.

    2015-09-01

    Woodlands represent highly significant carbon sinks globally, though could lose this function under future climatic change. Effective large-scale monitoring of these woodlands has a critical role to play in mitigating for, and adapting to, climate change. Mediterranean woodlands have low carbon densities, but represent important global carbon stocks due to their extensiveness and are particularly vulnerable because the region is predicted to become much hotter and drier over the coming century. Airborne lidar is already recognized as an excellent approach for high-fidelity carbon mapping, but few studies have used multi-temporal lidar surveys to measure carbon fluxes in forests and none have worked with Mediterranean woodlands. We use a multi-temporal (five year interval) airborne lidar dataset for a region of central Spain to estimate above-ground biomass (AGB) and carbon dynamics in typical mixed broadleaved/coniferous Mediterranean woodlands. Field calibration of the lidar data enabled the generation of grid-based maps of AGB for 2006 and 2011, and the resulting AGB change were estimated. There was a close agreement between the lidar-based AGB growth estimate (1.22 Mg ha-1 year-1) and those derived from two independent sources: the Spanish National Forest Inventory, and a~tree-ring based analysis (1.19 and 1.13 Mg ha-1 year-1, respectively). We parameterised a simple simulator of forest dynamics using the lidar carbon flux measurements, and used it to explore four scenarios of fire occurrence. Under undisturbed conditions (no fire occurrence) an accelerating accumulation of biomass and carbon is evident over the next 100 years with an average carbon sequestration rate of 1.95 Mg C ha-1 year-1. This rate reduces by almost a third when fire probability is increased to 0.01, as has been predicted under climate change. Our work shows the power of multi-temporal lidar surveying to map woodland carbon fluxes and provide parameters for carbon dynamics models. Space

  7. Are emissions of black carbon from gasoline vehicles overestimated? Real-time, in situ measurement of black carbon emission factors.

    PubMed

    Wang, Yang; Xing, Zhenyu; Zhao, Shuhui; Zheng, Mei; Mu, Chao; Du, Ke

    2016-03-15

    Accurately quantifying black carbon (BC) emission factors (EFs) is a prerequisite for estimation of BC emission inventory. BC EFs determined by measuring BC at the roadside or chasing a vehicle on-road may introduce large uncertainty for low emission vehicles. In this study, BC concentrations were measured inside the tailpipe of gasoline vehicles with different engine sizes under different driving modes to determine the respective EFs. BC EFs ranged from 0.005-7.14 mg/kg-fuel under the speeds of 20-70 km/h, 0.05-28.95 mg/kg-fuel under the accelerations of 0.5-1.5m/s(2). Although the water vapor in the sampling stream could result in an average of 12% negative bias, the BC EFs are significantly lower than the published results obtained with roadside or chasing vehicle measurement. It is suggested to conduct measurement at the tailpipe of gasoline vehicles instead of in the atmosphere behind the vehicles to reduce the uncertainty from fluctuation in ambient BC concentration. PMID:26799329

  8. Effect of Carbon Black on Dielectric and Microwave Absorption Properties of Carbon Black/Cordierite Plasma-Sprayed Coatings

    NASA Astrophysics Data System (ADS)

    Su, Jinbu; Zhou, Wancheng; Liu, Yi; Qing, Yuchang; Luo, Fa; Zhu, Dongmei

    2015-06-01

    Carbon black (CB)/cordierite composite coatings with different CB contents were fabricated by a multi-function micro-plasma spraying system developed by the Second Artillery Engineering College. Scanning electron microscopy was employed to investigate the microstructure of the spray-dried powders and as-sprayed coatings. The complex permittivities of the coatings and powders with different CB contents were investigated at the frequency of 8.2-12.4 GHz. The results show that both real and imaginary part of the permittivity increase with increasing CB content, which can be ascribed to the increase of the number of micro-capacitors and the polarization centers. Reflection loss of the as-sprayed coatings with different CB contents and thicknesses was calculated according to the transmission line theory. The coating with 4.54% CB content and 3.0 mm thickness shows optical microwave absorption with a minimum reflection loss of -23.90 dB at 10.13 GHz and reflection loss less than -9 dB over the whole investigated frequency.

  9. Identifying a Sea Breeze Circulation Pattern Over the Los Angeles Basin Using Airborne In Situ Carbon Dioxide Measurements

    NASA Astrophysics Data System (ADS)

    Brannan, A. L.; Schill, S.; Trousdell, J.; Heath, N.; Lefer, B. L.; Yang, M. M.; Bertram, T. H.

    2014-12-01

    The Los Angeles Basin in Southern California is an optimal location for a circulation study, due to its location between the Pacific Ocean to the west and the Santa Monica and San Gabriel mountain ranges to the east, as well as its booming metropolitan population. Sea breeze circulation carries air at low altitudes from coastal to inland regions, where the air rises and expands before returning back towards the coast at higher altitudes. As a result, relatively clean air is expected at low altitudes over coastal regions, but following the path of sea breeze circulation should increase the amount of anthropogenic influence. During the 2014 NASA Student Airborne Research Program, a highly modified DC-8 aircraft completed flights from June 23 to 25 in and around the LA Basin, including missed approaches at four local airports—Los Alamitos and Long Beach (coastal), Ontario and Riverside (inland). Because carbon dioxide (CO2) is chemically inert and well-suited as a conserved atmospheric tracer, the NASA Langley Atmospheric Vertical Observations of CO2 in the Earth's Troposphere (AVOCET) instrument was used to make airborne in situ carbon dioxide measurements. Combining measured wind speed and direction data from the aircraft with CO2 data shows that carbon dioxide can be used to trace the sea breeze circulation pattern of the Los Angeles basin.

  10. Impacts of black carbon and co-pollutant emissions from transportation sector in Mexico City

    NASA Astrophysics Data System (ADS)

    Zavala, Miguel; Almanza, Victor; Garcia, Agustin; Jazcilevich, Aron; Lei, Wenfang; Molina, Luisa

    2016-04-01

    Black carbon is one of the most important short-lived climate-forcing agents, which is harmful to human health and also contributes significantly to climate change. Transportation is one of the largest sources of black carbon emissions in many megacities and urban complexes, with diesel vehicles leading the way. Both on-road and off-road vehicles can emit substantial amounts of harmful BC-containing particulate matter (PM) and are also responsible for large emissions of carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and many other co-emitted volatile organic compounds (VOCs). Regionally, black carbon emissions contributions from mobile sources may vary widely depending on the technical characteristics of the vehicle fleet, the quality and chemical properties of the fuels consumed, and the degree of local development and economic activities that foster wider and more frequent or intensive use of vehicles. This presentation will review and assess the emissions of black carbon from the on-road and off-road transportation sector in the Mexico City Metropolitan Area. Viable mitigation strategies, including innovative technological alternatives to reduce black carbon and co-pollutants in diesel vehicles and their impacts on climate, human health and ecosystems will be described.

  11. 20 years of Black Carbon measurements in Germany

    NASA Astrophysics Data System (ADS)

    Kutzner, Rebecca; Quedenau, Jörn; Kuik, Friderike; von Schneidemesser, Erika; Schmale, Julia

    2016-04-01

    Black Carbon (BC) is an important short-lived climate-forcing pollutant contributing to global warming through absorption of sunlight. At the same time, BC, as a component of particulate matter (PM) exerts adverse health effects, like decreased lung function and exacerbated asthma. Globally, anthropogenic emission sources of BC include residential heating, transport, and agricultural fires, while the dominant natural emission sources are wildfires. Despite the various adverse effects of BC, legislation that requires mandatory monitoring of BC concentrations does not currently exist in the European Union. Instead, BC is only indirectly monitored as component of PM10 and PM2.5 (particulate matter with a diameter smaller 10 μm and 2.5 μm). Before the introduction of mandatory PM10 and PM2.5 monitoring in the European Union in 2005 and 2015, respectively, 'black smoke', a surrogate for BC, was a required measurement in Germany from the early 1990s. The annual mean limit value was 14 μg m-3 from 1995 and 8 μg m-3 from 1998 onwards. Many 'black smoke' measurements were stopped in 2004, with the repeal of the regulations obtaining at the time. However, in most German federal states a limited number BC monitoring stations continued to operate. Here we present a synthesis of BC data from 213 stations across Germany covering the period between 1994 and 2014. Due to the lack of a standardized method and respective legislation, the data set is very heterogeneous relying on twelve different measurement methods including chemical, optical, and thermal-optical methods. Stations include locations classified as background, urban-background, industrial and traffic among other types. Raw data in many different formats has been modelled and integrated in a relational database, allowing various options for further data analysis. We highlight results from the year 2009, as it is the year with the largest measurement coverage based on the same measurement method, with 30 stations. In

  12. Cellphones as a Distributed Platform for Black Carbon Data Collection

    NASA Astrophysics Data System (ADS)

    Ramanathan, N.; Ramana, M.; Lukac, M. L.; Siva, P.; Ahmed, T.; Kar, A.; Rehman, I.; Ramanathan, V.

    2010-12-01

    Black carbon (BC), the visible component of soot that gives emissions such as diesel engine exhaust their dark color, has come to be recognized as a major contributor to global warming, and a frontline concern for climate change strategies (Ramanathan 2001, Jacobson 2010). We have developed a new low-cost instrument for gathering and measuring atmospheric BC concentrations that leverages cellphones to transmit data from an air filtration unit to a centralized database for analysis. Our new system relies on image processing techniques, as opposed to other more expensive optical methods, to interpret images of filters captured with a cellphone camera. As a result, the entire system costs less than $500 (and is orders of magnitude cheaper than an Aethalometer, the prevailing method for measuring atmospheric BC). We are working with three community groups in Los Angeles, and will recruit three groups in the San Francisco Bay Area, to enable 40 citizens to be actively engaged in monitoring BC across California. We are working with The Energy Resources Institute, an international NGO based in India, to deploy this instrument with 60 people in conjunction with Project Surya, which aims to deploy clean cookstoves and rigorously evaluate their impact on BC emissions. Field tests of this new instrument performed in California report an average error of 0.28 µg/m3 when compared with an Aethelometer. These excellent results hold the promise of making large-scale data collection of BC feasible and relatively easy to reproduce (Ramanathan et al., forthcoming). The use of cellphones for data collection permits monitoring of BC to occur on a greater, more comprehensive scale not previously possible, and serves as a means of instituting more precise, variation-sensitive evaluations of emissions. By storing the data in a publicly available repository, our system will provide real-time access to mass-scale BC measurements to researchers and the public. Through our pilot

  13. Linearity of Climate Response to Increases in Black Carbon Aerosols

    SciTech Connect

    Mahajan, Salil; Evans, Katherine J.; Hack, James J.; Truesdale, John

    2013-04-19

    The impact of absorbing aerosols on global climate are not completely understood. Here, we present results of idealized experiments conducted with the Community Atmosphere Model (CAM4) coupled to a slab ocean model (CAM4-SOM) to simulate the climate response to increases in tropospheric black carbon aerosols (BC) by direct and semi-direct effects. CAM4-SOM was forced with 0, 1x, 2x, 5x and 10x an estimate of the present day concentration of BC while maintaining their estimated present day global spatial and vertical distribution. The top of the atmosphere (TOA) radiative forcing of BC in these experiments is positive (warming) and increases linearly as the BC burden increases. The total semi-direct effect for the 1x experiment is positive but becomes increasingly negative for higher BC concentrations. The global average surface temperature response is found to be a linear function of the TOA radiative forcing. The climate sensitivity to BC from these experiments is estimated to be 0.42 K $ W^{-1} m^{2}$ when the semi-direct effects are accounted for and 0.22 K $ W^{-1} m^{2}$ with only the direct effects considered. Global average precipitation decreases linearly as BC increases, with a precipitation sensitivity to atmospheric absorption of 0.4 $\\%$ $W^{-1}m^{2}$ . The hemispheric asymmetry of BC also causes an increase in southward cross-equatorial heat transport and a resulting northward shift of the inter-tropical convergence zone in the simulations at a rate of 4$^{\\circ}$N $ PW^{-1}$. Global average mid- and high-level clouds decrease, whereas the low-level clouds increase linearly with BC. The increase in marine stratocumulus cloud fraction over the south tropical Atlantic is caused by increased BC-induced diabatic heating of the free troposphere.

  14. Black Carbon Mass Concentration in California Mountain Snow

    NASA Astrophysics Data System (ADS)

    Hadley, O. L.; Corrigan, C.; Kirchstetter, T. W.; Cliff, S. S.; Ramanathan, V.

    2007-12-01

    Recent modeling studies have shown that deposition of black carbon (BC) to snow and ice lowers the albedo of snow and exerts a positive forcing on the climate. This effect is also a likely contributor to the observed ice and snow retreat in glaciers, ice sheets, and mountain snow pack. Observational data of actual BC concentrations in snow, which would help to constrain and validate these results, are scarce. This study presents the concentration of BC in fresh snow measured at two mountain locations in Northern California (Lassen Volcano Natl. Park and Donner Summit), as well as that in coastal rainfall at Trinidad Head, CA. These measurements are the first of this kind made in California. Average BC concentration at Lassen Natl. Park and Donner summit were respectively 6.8 and 9.7 ng per gram of snow. When placed in context with the modeled effect of BC on fresh snow albedo, these concentrations indicate a lowering of the snow albedo by 0.5 to 0.8%. As the snow pack ages, models predict that this effect will be increasingly amplified. Measurements of ambient aerosols during the rain events, as well as HySPLIT back-trajectories, provide additional information regarding possible sources of BC in California mountain snow packs. For the samples collected in this study, most of the soot in the snow appears to be of local origin. The average BC concentration in the coastal rain was 6.0 ng per gram of water, with the highest concentrations (12 ng/g) corresponding to the only back-trajectories clearly indicative of long-range trans-Pacific transport.

  15. Black Carbon Increases Cation Exchange Capcity in Soils

    SciTech Connect

    Liang,B.; Lehmann, J.; Solomon, D.; Kinyangi, J.; Grossman, J.; ONeill, B.; Skjemstad, J.; Thies, J.; Luizao, F.; et al.

    2006-01-01

    Black Carbon (BC) may significantly affect nutrient retention and play a key role in a wide range of biogeochemical processes in soils, especially for nutrient cycling. Anthrosols from the Brazilian Amazon (ages between 600 and 8700 yr BP) with high contents of biomass-derived BC had greater potential cation exchange capacity (CEC measured at pH 7) per unit organic C than adjacent soils with low BC contents. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy coupled with scanning transmission X-ray microscopy (STXM) techniques explained the source of the higher surface charge of BC compared with non-BC by mapping cross-sectional areas of BC particles with diameters of 10 to 50 {micro}m for C forms. The largest cross-sectional areas consisted of highly aromatic or only slightly oxidized organic C most likely originating from the BC itself with a characteristic peak at 286.1 eV, which could not be found in humic substance extracts, bacteria or fungi. Oxidation significantly increased from the core of BC particles to their surfaces as shown by the ratio of carboxyl-C/aromatic-C. Spotted and non-continuous distribution patterns of highly oxidized C functional groups with distinctly different chemical signatures on BC particle surfaces (peak shift at 286.1 eV to a higher energy of 286.7 eV) indicated that non-BC may be adsorbed on the surfaces of BC particles creating highly oxidized surface. As a consequence of both oxidation of the BC particles themselves and adsorption of organic matter to BC surfaces, the charge density (potential CEC per unit surface area) was greater in BC-rich Anthrosols than adjacent soils. Additionally, a high specific surface area was attributable to the presence of BC, which may contribute to the high CEC found in soils that are rich in BC.

  16. Stability of Biomass-derived Black Carbon in Soils

    SciTech Connect

    Liang, Biqing; Lehmann, Johannes C.; Solomon, Dawit; Sohi, Saran; Thies, Janice E.; Skjemstad, Jan O.; Luizao, Flavio J.; Engelhard, Mark H.; Neves, Eduaro G.; Wirick, Sue

    2008-12-15

    Black carbon (BC) may play an important role in the global C budget, due to its potential to act as a significant removal (sink) of atmospheric CO2. In order to fully evaluate the influence of BC on the global C cycle, a sound understanding of the stability of BC is required. The biochemical stability of BC was assessed in a chronosequence of high-BC containing Anthrosols from the central Amazon, Brazil, using a range of spectroscopic and biological methods. Results revealed that the Anthrosols had 61-80% lower (P<0.05) CO2 evolution over 532 days compared to that in the corresponding adjacent soils with low BC contents. No significant (P>0.05) differences of CO2 respiration were observed between Anthrosols with contrasting ages of BC and soil textures. Molecular forms of core regions of micrometer-sized BC particles quantified by synchrotron-based near-edge x-ray fine structure (NEXAFS) spectroscopy coupled to scanning x-ray transmission microscopy (STXM) remained similar regardless of their ages (600 to 8,700 years) and closely resembled the spectral characteristics of fresh BC. Deconvolution of NEXAFS spectra revealed greater oxidation on the surfaces of BC particles with little penetration into the core of the particles. The similar C mineralization between different BC-rich soils regardless of soil texture underpins the importance of chemical recalcitrance for the stability of BC, in contrast to adjacent soils which showed the highest mineralization in the sandiest soil. However, C distribution between free, intra-aggregate and organo-mineral pools was significantly different between soils with high and low BC contents, suggesting some degree of physical stabilization, and BC-rich Anthrosols had higher proportions (72-90%) of C in the organo-mineral fraction than BC-poor adjacent soils (2-70%).

  17. Speciation of the ionizable antibiotic sulfamethazine on black carbon (biochar).

    PubMed

    Teixidó, Marc; Pignatello, Joseph J; Beltrán, José L; Granados, Mercè; Peccia, Jordan

    2011-12-01

    Adsorption of ionizable compounds by black carbon is poorly characterized. Adsorption of the veterinary antibiotic sulfamethazine (SMT; a.k.a., sulfadimidine; pK(a1) = 2.28, pK(a2) = 7.42) on a charcoal was determined as a function of concentration, pH, inorganic ions, and organic ions and molecules. SMT displayed unconventional adsorption behavior. Despite its hydrophilic nature (log K(ow) = 0.27), the distribution ratio K(d) at pH 5, where SMT(0) prevails, was as high as 10(6) L kg(-1), up to 10(4) times greater than literature reported K(oc). The K(d) decreases at high and low pH but not commensurate with the decline in K(ow) of the ionized forms. At pH 1, where SMT(+) is predominant and the surface is positive, a major driving force is π-π electron donor-acceptor interaction of the protonated aniline ring with the π-electron rich graphene surface, referred to as π(+)-π EDA, rather than ordinary electrostatic cation exchange. In the alkaline region, where SMT(-) prevails and the surface is negative, adsorption is accompanied by near-stoichiometric proton exchange with water, leading to the release of OH(-) and formation of an exceptionally strong H-bond between SMT(0) and a surface carboxylate or phenolate, classified as a negative charge-assisted H-bond, (-)CAHB. At pH 5, SMT(0) adsorption is accompanied by partial proton release and is competitive with trimethylphenylammonium ion, signifying contributions from SMT(+) and/or the zwitterion, SMT(±), which take advantage of π(+)-π EDA interaction and Coulombic attraction to deprotonated surface groups. In essence, both pK(a1) and pK(a2) increase, and SMT(±) is stabilized, in the adsorbed relative to the dissolved state. PMID:22026725

  18. New Routes to Functionalize Carbon Black for Polypropylene Nanocomposites.

    PubMed

    Shepherd, Céline; Hadzifejzovic, Emina; Shkal, Fatma; Jurkschat, Kerstin; Moghal, Jonathan; Parker, Emily M; Sawangphruk, Montree; Slocombe, Daniel R; Foord, John S; Moloney, Mark G

    2016-08-01

    Methods for chemical surface functionalization for carbon black (CB) nanoparticles were studied to produce (CB)/polypropylene (PP) nanocomposites with superior electrical and thermal properties. Nanoparticle dispersion is known to directly control the extent to which nanocomposites maximize the unique attributes of their nanoscale fillers. As a result, tailored nanoparticle surface chemistry is a widely utilized method to enhance the interfacial interactions between nanoparticles and polymer matrices, assisting improved filler dispersion. In this work, a rapid chemical functionalization approach using a number of diarylcarbene derivatives, followed by the azo-coupling of substituted diazonium salts, for the covalent introduction of selected functional groups to the CB surface, is reported. Characterization of the modified CB by XPS, TGA, CHN, and ATR-IR collectively confirmed surface functionalization, estimating surface grafting densities of the order of 10(13) and 10(14) molecules/cm(2). Nanocomposites, synthesized by solvent mixing PP with pristine and modified CB, demonstrated macroscopic property changes as a result of the nanoparticle surface functionalization. Pronounced improvements were observed for PP nanocomposites prepared with a dodecyl-terminated diaryl functionalized CB, in which TEM analysis established improved nanofiller dispersion owing to the enhanced CB-PP interfacial interactions in the nanocomposite. Observed dielectric relaxation responses at 20 wt % loading and a reduced percolation threshold realized conductivities of 1.19 × 10(-4) S cm(-1) at 10 wt %, compared to 2.62 × 10(-15) S cm(-1) for pristine CB/PP nanocomposites at the same filler loading. In addition, thermal properties signify an increase in the number of nucleation sites by the raised degree of crystallinity as well as increased melting and crystallization temperatures. PMID:27417277

  19. Black carbon aerosols in urban air in South Asia

    NASA Astrophysics Data System (ADS)

    Dutkiewicz, Vincent A.; Alvi, Sofia; Ghauri, Badar M.; Choudhary, M. Iqbal; Husain, Liaquat

    We report data from a yearlong (2006-2007) study of black carbon concentrations ([BC]) measured at 5-min intervals with an Aethalometer in Karachi, Pakistan. Daily mean [BC] varied from about 1 to 15 μg m -3. However, short-term spikes exceeding 40 μg m -3 were common, occurring primarily during the morning and evening rush-hour periods. The [BC] values were highest during November through February, ˜10 μg m -3, and lowest during June through September, ˜2 μg m -3. Diurnal, seasonal, and day-of-the-week trends are discussed. It is demonstrated that these trends are strongly affected by meteorological patterns. A simple expression is applied to the concentration profiles to separate the effects of meteorological conditions and elucidate the underlying emissions patterns. Daily emissions varied from 14,000 to 22,000 kg of BC per day. When integrated over the year emissions for Karachi Proper were estimated at 6.7 kilometric tons per year and emissions for greater Karachi were 17.5 kilometric tons per year. Folding in the populations of each area yields BC emissions of 0.74 and 1.1 kg per person per year, respectively. Applying the model to previously collected data at Lahore, Pakistan yields emissions during November-January that are around a factor of two higher than those in Karachi, but because the BC measurements in Lahore covered only three months, no estimates of annual emissions were attempted. Given the large populations of these cities the local health impact from PM alone is expected to be severe but because of the high [BC] emissions the impact on the global climate may be equally significant.

  20. Climate Response of Direct Radiative Forcing of Anthropogenic Black Carbon

    NASA Technical Reports Server (NTRS)

    Chung, Serena H.; Seinfeld,John H.

    2008-01-01

    The equilibrium climate effect of direct radiative forcing of anthropogenic black carbon (BC) is examined by 100-year simulations in the Goddard Institute for Space Studies General Circulation Model II-prime coupled to a mixed-layer ocean model. Anthropogenic BC is predicted to raise globally and annually averaged equilibrium surface air temperature by 0.20 K if BC is assumed to be externally mixed. The predicted increase is significantly greater in the Northern Hemisphere (0.29 K) than in the Southern Hemisphere (0.11 K). If BC is assumed to be internally mixed with the present day level of sulfate aerosol, the predicted annual mean surface temperature increase rises to 0.37 K globally, 0.54 K for the Northern Hemisphere, and 0.20 K for the Southern Hemisphere. The climate sensitivity of BC direct radiative forcing is calculated to be 0.6 K W (sup -1) square meters, which is about 70% of that of CO2, independent of the assumption of BC mixing state. The largest surface temperature response occurs over the northern high latitudes during winter and early spring. In the tropics and midlatitudes, the largest temperature increase is predicted to occur in the upper troposphere. Direct radiative forcing of anthropogenic BC is also predicted to lead to a change of precipitation patterns in the tropics; precipitation is predicted to increase between 0 and 20 N and decrease between 0 and 20 S, shifting the intertropical convergence zone northward. If BC is assumed to be internally mixed with sulfate instead of externally mixed, the change in precipitation pattern is enhanced. The change in precipitation pattern is not predicted to alter the global burden of BC significantly because the change occurs predominantly in regions removed from BC sources.

  1. On the black carbon problem and its solutions

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.

    2010-12-01

    Black carbon (BC) warms air temperatures in at least seven major ways: (a) directly absorbing downward solar radiation, (b) absorbing upward reflected solar radiation when it is situated above bright surfaces, such as snow, sea ice, and clouds, (c) absorbing some infrared radiation, (d) absorbing additional solar and infrared radiation upon obtaining a coating, (e) absorbing radiation multiply reflected within clouds when situated interstitially between cloud drops, (f) absorbing additional radiation when serving as CCN or scavenged inclusions within cloud drops, and (g) absorbing solar radiation when deposited on snow and sea ice, reducing the albedos of both. Modeling of the climate effects of BC requires treatment of all these processes in detail. In particular, treatment of BC absorption interstitially between cloud drops and from multiply-dispersed cloud drop BC inclusions must be treated simultaneously with treatment of cloud indirect effects to determine the net effects of BC on cloud properties. Here, results from several simulations of the effects of BC from fossil fuel and biofuel sources on global and regional climate and air pollution health are summarized. The simulations account for all the processes mentioned. Results are found to be statistically significant relative to chaotic variability in the climate system. Over time and in steady state, fossil-fuel soot plus biofuel soot are found to enhance warming more than methane. The sum of the soots causes less steady-state warming but more short term warming than does carbon dioxide. Thus eliminating soot emissions from both sources may be the fastest method of reducing rapid climate warming and possibly the only method of saving the Arctic ice. Eliminating such emissions may also reduce over 1.5 million deaths worldwide, particularly in developing countries. Short term mitigation options include the targeting of fossil-fuel and biofuel BC sources with particle traps, new stove technologies, and rural

  2. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

    NASA Astrophysics Data System (ADS)

    Massling, A.; Nielsen, I. E.; Kristensen, D.; Christensen, J. H.; Sørensen, L. L.; Jensen, B.; Nguyen, Q. T.; Nøjgaard, J. K.; Glasius, M.; Skov, H.

    2015-08-01

    Measurements of equivalent black carbon (EBC) in aerosols at the high Arctic field site Villum Research Station (VRS) at Station Nord in North Greenland showed a seasonal variation in EBC concentrations with a maximum in winter and spring at ground level. Average measured concentrations were about 0.067 ± 0.071 for the winter and 0.011 ± 0.009 for the summer period. These data were obtained using a multi-angle absorption photometer (MAAP). A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. Here, measured average concentrations were about 0.485 ± 0.397 for the winter and 0.112 ± 0.072 for the summer period. A correlation between EBC and sulfate concentrations was observed over the years 2011 to 2013 stating a correlation coefficient of R2 = 0.72. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. BC and sulfate are known to have only partly similar sources with respect to their transport pathways when reaching the high Arctic. Aging processes may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon) based on a thermo-optical method were determined and compared to EBC measurements. EBC measurements were generally higher, but a correlation between EC and EBC resulted in a correlation coefficient of R2 = 0.64. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Eulerian Hemispheric Model, DEHM. Good agreement between measured and

  3. Increased fire frequency optimization of black carbon mixing and storage

    NASA Astrophysics Data System (ADS)

    Pyle, Lacey; Masiello, Caroline; Clark, Kenneth

    2016-04-01

    Soil carbon makes up a substantial part of the global carbon budget and black carbon (BC - produced from incomplete combustion of biomass) can be significant fraction of soil carbon. Soil BC cycling is still poorly understood - very old BC is observed in soils, suggesting recalcitrance, yet in short term lab and field studies BC sometimes breaks down rapidly. Climate change is predicted to increase the frequency of fires, which will increase global production of BC. As up to 80% of BC produced in wildfires can remain at the fire location, increased fire frequency will cause significant perturbations to soil BC accumulation. This creates a challenge in estimating soil BC storage, in light of a changing climate and an increased likelihood of fire. While the chemical properties of BC are relatively well-studied, its physical properties are much less well understood, and may play crucial roles in its landscape residence time. One important property is density. When BC density is less than 1 g/cm3 (i.e. the density of water), it is highly mobile and can easily leave the landscape. This landscape mobility following rainfall may inflate estimates of its degradability, making it crucial to understand both the short- and long term density of BC particles. As BC pores fill with minerals, making particles denser, or become ingrown with root and hyphal anchors, BC is likely to become protected from erosion. Consequently, how quickly BC is mixed deeper into the soil column is likely a primary controller on BC accumulation. Additionally the post-fire recovery of soil litter layers caps BC belowground, protecting it from erosional forces and re-combustion in subsequent fires, but still allowing bioturbation deeper into the soil column. We have taken advantage of a fire chronosequence in the Pine Barrens of New Jersey to investigate how density of BC particles change over time, and how an increase in fire frequency affects soil BC storage and soil column movement. Our plots have

  4. Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

    PubMed

    Clack, Herek L

    2012-07-01

    The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions. PMID:22663136

  5. Black Carbon and Particulate Matter (PM2.5) Concentrations in New York City’s Subway Stations

    PubMed Central

    2015-01-01

    The New York City (NYC) subway is the main mode of transport for over 5 million passengers on an average weekday. Therefore, airborne pollutants in the subway stations could have a significant impact on commuters and subway workers. This study looked at black carbon (BC) and particulate matter (PM2.5) concentrations in selected subway stations in Manhattan. BC and PM2.5 levels were measured in real time using a Micro-Aethalometer and a PDR-1500 DataRAM, respectively. Simultaneous samples were also collected on quartz filters for organic and elemental carbon (OC/EC) analysis and on Teflon filters for gravimetric and trace element analysis. In the underground subway stations, mean real time BC concentrations ranged from 5 to 23 μg/m3, with 1 min average peaks >100 μg/m3, while real time PM2.5 levels ranged from 35 to 200 μg/m3. Mean EC levels ranged from 9 to 12.5 μg/m3. At street level on the same days, the mean BC and PM2.5 concentrations were below 3 and 10 μg/m3, respectively. This study shows that both BC soot and PM levels in NYC’s subways are considerably higher than ambient urban street levels and that further monitoring and investigation of BC and PM subway exposures are warranted. PMID:25409007

  6. Reduction of nitroaromatics sorbed to black carbon by direct reaction with sorbed sulfides.

    PubMed

    Xu, Wenqing; Pignatello, Joseph J; Mitch, William A

    2015-03-17

    Sorption to black carbons is an important sink for organic contaminants in sediments. Previous research has suggested that black carbons (graphite, activated carbon, and biochar) mediate the degradation of nitrated compounds by sulfides by at least two different pathways: reduction involving electron transfer from sulfides through conductive carbon regions to the target contaminant (nitroglycerin) and degradation by sulfur-based intermediates formed by sulfide oxidation (RDX). In this study, we evaluated the applicability of black carbon-mediated reactions to a wider variety of contaminant structures, including nitrated and halogenated aromatic compounds, halogenated heterocyclic aromatic compounds, and halogenated alkanes. Among these compounds, black carbon-mediated transformation by sulfides over a 3-day time scale was limited to nitroaromatic compounds. The reaction for a series of substituted nitroaromatics proceeded by reduction, as indicated by formation of 3-bromoaniline from 3-bromonitrobenzene, and inverse correlation of log kobs with energy of the lowest unoccupied molecular orbital (ELUMO). The log kobs was correlated with sorbed sulfide concentration, but no reduction of 3-bromonitrobenzene was observed in the presence of graphite and sulfite, thiosulfate, or polysulfides. Whereas nitroglycerin reduction occurred in an electrochemical cell containing sheet graphite electrodes in which the reagents were placed in separate compartments, nitroaromatic reduction only occurred when sulfides were present in the same compartment. The results suggest that black carbon-mediated reduction of sorbed nitroaromatics by sulfides involves electron transfer directly from sorbed sulfides rather than transfer of electrons through conductive carbon regions. The existence of three different reaction pathways suggests a complexity to the sulfide-carbon system compared to the iron-carbon system, where contaminants are reduced by electron transfer through conductive carbon

  7. Dynamac molecular structure of plant biomass-derived black carbon (Biochar)

    EPA Science Inventory

    Char black carbon (BC), the solid residue of incomplete combustion, is continuously being added to soils and sediments due to natural vegetation fires, anthropogenic pollution, and new strategies for carbon sequestration (“biochar”). Here we present a molecular-level assessment o...

  8. Is Carbon Black a Suitable Model Colloidal Substrate for Diesel Soot?

    PubMed

    Growney, David J; Mykhaylyk, Oleksandr O; Middlemiss, Laurence; Fielding, Lee A; Derry, Matthew J; Aragrag, Najib; Lamb, Gordon D; Armes, Steven P

    2015-09-29

    Soot formation in diesel engines is known to cause premature engine wear. Unfortunately, genuine diesel soot is expensive to generate, so carbon blacks are often used as diesel soot mimics. Herein, the suitability of a commercial carbon black (Regal 250R) as a surrogate for diesel soot dispersed in engine base oil is examined in the presence of two commonly used polymeric lubricant additives. The particle size, morphology, and surface composition of both substrates are assessed using BET surface area analysis, TEM, and XPS. The extent of adsorption of a poly(ethylene-co-propylene) (dOCP) statistical copolymer or a polystyrene-block-poly(ethylene-co-propylene) (PS-PEP) diblock copolymer onto carbon black or diesel soot from n-dodecane is compared indirectly using a supernatant depletion assay technique via UV spectroscopy. Thermogravimetric analysis is also used to directly determine the extent of copolymer adsorption. Degrees of dispersion are examined using optical microscopy, TEM, and analytical centrifugation. SAXS studies reveal some structural differences between carbon black and diesel soot particles. The mean radius of gyration determined for the latter is significantly smaller than that calculated for the former, and in the absence of any copolymer, diesel soot suspended in n-dodecane forms relatively loose mass fractals compared to carbon black. SAXS provides evidence for copolymer adsorption and indicates that addition of either copolymer transforms the initially compact agglomerates into relatively loose aggregates. Addition of dOCP or PS-PEP does not significantly affect the structure of the carbon black primary particles, with similar results being observed for diesel soot. In favorable cases, remarkably similar data can be obtained for carbon black and diesel soot when using dOCP and PS-PEP as copolymer dispersants. However, it is not difficult to identify simple copolymer-particle-solvent combinations for which substantial differences can be observed

  9. Mass spectrometry of refractory black carbon particles from six sources: carbon-cluster and oxygenated ions

    NASA Astrophysics Data System (ADS)

    Corbin, J. C.; Sierau, B.; Gysel, M.; Laborde, M.; Keller, A.; Kim, J.; Petzold, A.; Onasch, T. B.; Lohmann, U.; Mensah, A. A.

    2014-03-01

    We discuss the major mass spectral features of different types of refractory carbonaceous particles, ionized after laser vaporization with an Aerodyne high-resolution soot-particle aerosol mass spectrometer (SP-AMS). The SP-AMS was operated with a switchable 1064 nm laser and a 600 °C thermal vaporizer, yielding respective measurements of the refractory and non-refractory particle components. Six samples were investigated, all of which were composed primarily of refractory material: fuel-rich and fuel-lean propane/air diffusion-flame combustion particles; graphite-spark-generated particles; a commercial fullerene-enriched soot; Regal Black, a commercial carbon black; and nascent aircraft-turbine combustion particles. All samples exhibited a spectrum of carbon-cluster ions Cxn+ in their refractory mass spectrum. Smaller clusters (x < 6) were found to dominate the Cxn+ distribution. For fullerene soot, fuel-rich-flame particles and spark-generated particles, significant Cxn+ clusters at x ≫ 6 were present, with significant contributions from multiply charged ions (n > 1). In all six cases, the ions C1+ and C3+ contributed over 60% to the total C1 5 were present. When such signals were present, C1+ / C3+ was close to 1. When absent, C1+ / C3+ was < 0.8. This ratio may therefore serve as a proxy to distinguish between the two types of spectra in atmospheric SP-AMS measurements. Significant refractory oxygenated ions such as CO+ and CO2+ were also observed for all samples. We discuss these signals in detail for Regal Black, and describe their formation via decomposition of oxygenated moieties incorporated into the refractory carbon structure. These species may be of importance in atmospheric processes such as water uptake and heterogeneous chemistry. If atmospherically stable, these oxidized species may be useful for distinguishing

  10. Numerical Analysis of Carbon Black Production from Sub-Quality Natural Gas

    NASA Astrophysics Data System (ADS)

    Moghiman, M.; Javadi, M.; Ghodsirad, M. H.; Hosseini, N.; Soleimani, M.

    2008-09-01

    The objective of this paper is computational investigation of the carbon black production through the oxidative thermal decomposition of waste gases contain CH4 and H2S without requiring a H2S separation process. The chemical reaction model, which involves solid carbon, sulfur compounds and other precursor species for formation carbon black, based on an assumed Probability Density Function (PDF) is parameterized by the mean and variance of mixture fraction and β-PDF shape. The effects of feedstock mass flow rate and reactor temperature on carbon black, soot, CO, S2, SO2, COS and CS2 formation are investigated. The results show that the major factor influencing CH4 and H2S conversions is reactor temperature. The results reveal that at any temperature, H2S conversion is less than that of CH4 especially at temperature below 1300 °k wherein H2S conversion is less than 5%.

  11. An observation-based estimate of global black carbon and brown carbon AODs and radiative forcings

    NASA Astrophysics Data System (ADS)

    Chung, C. E.; Ramanathan, V.

    2010-12-01

    We combined AERONET AODs with MODIS AODs, and obtained global AODs. Using the wavelength dependence of AERONET SSA, we extracted black carbon (BlC), brown carbon (BrC) and dust components of AODs. The assumptions we made are that a) BlC SSA and BlC SSA wavelength-dependence are influenced by BlC particles mixed with non-absorbing aerosols and b) brown carbon spheres identified by Alexander et al. (2008) represent all the BrC particles. Our global BlC AOD is 0.007 and accounts for 4.7% of total AOD. Our BrC AOD is 0.0027 (about 2% of total AOD) and the dust AOD is 0.036 (about 24% of total AOD). In comparison, AEROCOM models give dust AOD in the range from 7% to 44% while AEOCOM BlC AOD ranges from 0.4% to 5.9%. Our BlC AOD is greater than average AEROCOM BlC AOD. Using our observation-based AODs, we calculated radiative forcing for BrC and BlC using the Monte-Carlo Aerosol Cloud Radiaiton (MACR) model. The results will be presented at AGU.

  12. Black carbon from the Mississippi River: quantities, sources, and potential implications for the global carbon cycle.

    PubMed

    Mitra, Siddhartha; Bianchi, Thomas S; McKee, Brent A; Sutula, Martha

    2002-06-01

    Black carbon (BC) may be a major component of riverine carbon exported to the ocean, but its flux from large rivers is unknown. Furthermore, the global distribution of BC between natural and anthropogenic sources remains uncertain. We have determined BC concentrations in suspended sediments of the Mississippi River, the 7th largest river in the world in terms of sediment and water discharge, during high flow and low flow in 1999. The 1999 annual flux of BC from the Mississippi River was 5 x 10(-4) petagrams (1 Pg = 10(15) g = 1 gigaton). We also applied a principal components analysis to particulate-phase high molecular weight polycyclic aromatic hydrocarbon isomer ratios in Mississippi River suspended sediments. In doing so, we determined that approximately 27% of the BC discharged from the Mississippi River in 1999 originated from fossil fuel combustion (coal and smelter-derived combustion), implicating fluvial BC as an important source of anthropogenic BC contamination into the ocean. Using our value for BC flux and the annual estimate for BC burial in ocean sediments, we calculate that, in 1999, the Mississippi River discharged approximately 5% of the BC buried annually in the ocean. These results have important implications, not only for the global carbon cycle but also for the fluvial discharge of particulate organic contaminants into the world's oceans. PMID:12075780

  13. Predicting the cropland soil organic carbon (SOC) distribution on a regional scale using airborne spectroscopy and topographic features

    NASA Astrophysics Data System (ADS)

    Doetterl, S.; Stevens, S.; Van Wesemael, B.; Quine, T. A.; Van Oost, K.

    2012-04-01

    The effects of soil redistribution on the carbon cycle have recently been receiving growing attention. In eroding agricultural landscapes, carbon gets transported from erosional to depositional landscape features forming a heterogeneous pattern in quantity and quality of the distributed carbon. At present, methods and research to characterize this horizontal (across the earth surface) and vertical (with depth) variability are focused on local slope scales. Approaches linking detailed local assessments to larger scales are limited. This significantly hampers our ability to understand the impact of soil redistribution processes on the global C cycle that occur at larger spatial and temporal scales. Here, we present a method to predict the SOC distribution on a regional scale for high-input cropping systems using a combination of airborne spectroscopy, GIS-based analysis of a digital elevation model (DEM) and calibration with empirical data. For a North/South transect in Luxembourg, spatial modeling is used to integrate soil surface SOC data from airborne image spectroscopy (2m resolution), vertical SOC gradients from high resolution (0.10m) soil sampling and derivates of a high-res elevation model (5m resolution). This allows the prediction of the 3D distribution of cropland soil C to be interpolated over an area of c. 150 km2 in Luxemburg which is characterized by intensive agricultural land use, a high variability in soils and a complex topography. The model is able to predict patterns of C stock distribution for cropland on a regional scale using simple hydrologic and geomorphologic parameters and provides new insights into the spatial heterogeneity of soil carbon storage covering a large area. Eroding positions have a sharper decline of carbon content with depth than stable and especially depositional sites, which in contrast store high amounts of carbon in greater depths. Relative root mean square errors range between 23-49 % and the model is in good agreement

  14. Evaluation of Airborne Particle Emissions from Commercial Products Containing Carbon Nanotubes

    PubMed Central

    Huang, Guannan; Park, Jae Hong; Cena, Lorenzo G.; Shelton, Betsy L.; Peters, Thomas M.

    2012-01-01

    The emission of the airborne particles from epoxy resin test sticks with different CNT loadings and two commercial products were characterized while sanding with three grit sizes and three disc sander speeds. The total number concentrations, respirable mass concentrations, and particle size number/mass distributions of the emitted particles were measured using a condensation particle counter, an optical particle counter, and a scanning mobility particle sizer. The emitted particles were sampled on a polycarbonate filter and analyzed using electron microscopy. The highest number concentrations (arithmetic mean = 4670 particles/cm3) were produced with coarse sandpaper, 2% (by weight) CNT test sticks and medium disc sander speed, whereas the lowest number concentrations (arithmetic mean = 92 particles/cm3) were produced with medium sandpaper, 2% CNT test sticks and slow disc sander speed. Respirable mass concentrations were highest (arithmetic mean = 1.01 mg/m3) for fine sandpaper, 2% CNT test sticks and medium disc sander speed and lowest (arithmetic mean = 0.20 mg/m3) for medium sandpaper, 0% CNT test sticks and medium disc sander speed. For CNT-epoxy samples, airborne particles were primarily micrometer-sized epoxy cores with CNT protrusions. No free CNTs were observed in airborne samples, except for tests conducted with 4% CNT epoxy. The number concentration, mass concentration, and size distribution of airborne particles generated when products containing CNTs are sanded depends on the conditions of sanding and the characteristics of the material being sanded. PMID:23204914

  15. Photoacoustic measurements of black carbon light absorption coefficients in Irbid city, Jordan.

    PubMed

    Hamasha, Khadeejeh M; Arnott, W Patrick

    2010-07-01

    There is a need to recognize air pollution levels by particles, especially in developing countries such as Jordan where data are scarce due to the absence of routine monitoring of ambient air quality. This study aims at studying the air quality in different locations at Irbid, Jordan through the measurement and analysis of the time series of black carbon light absorption coefficients (B (abs)). Black carbon light absorption coefficients were measured with a photoacoustic instrument at a wavelength of 870 nm. The measurements were conducted during July 2007 at six sites in Irbid city, Jordan. Comparisons of black carbon concentrations at various locations were conducted to understand where values tend to be largest. The average value of B (abs) of all sites was 40.4 Mm(-1). The largest value of B (abs) was 61.2 Mm(-1) at Palestine Street which is located at a very crowded street in a highly populated region in the city center. The lowest value was 14.1 Mm(-1) at Thirtieth Street which is located at a main street in an open plain region in the east of the city. The black carbon light absorption coefficients fluctuate above a background level (transported black carbon from the neighboring states), which are almost identical at all sampling sites. The light absorption coefficients will be used as a benchmark in later years as combustion efficiencies and population patterns change. PMID:19479334

  16. The Effects of Black Carbon and Sulfate Aerosols in ChinaRegions on East Asia Monsoons

    SciTech Connect

    Yang, Bai; Liu, Yu; Sun, Jiaren

    2009-01-01

    In this paper we examine the direct effects of sulfate and black carbon aerosols in China on East Asia monsoons and its precipitation processes by using the CAM3.0 model. It is demonstrated that sulfate and black carbon aerosols in China both have the effects to weaken East Asia monsoons in both summer and winter seasons. However, they certainly differ from each other in affecting vertical structures of temperature and atmospheric circulations. Their differences are expected because of their distinct optical properties, i.e., scattering vs. absorbing. Even for a single type of aerosol, its effects on temperature structures and atmospheric circulations are largely season-dependent. Applications of T-test on our results indicate that forcing from black carbon aerosols over China is relatively weak and limited. It is also evident from our results that the effects of synthetic aerosols (sulfate and black carbon together) on monsoons are not simply a linear summation between these two types of aerosols. Instead, they are determined by their integrated optical properties. Synthetic aerosols to a large degree resemble effects of sulfate aerosols. This implies a likely scattering property for the integration of black carbon and sulfate aerosols in China.

  17. Migration of nanoparticles from plastic packaging materials containing carbon black into foodstuffs.

    PubMed

    Bott, Johannes; Störmer, Angela; Franz, Roland

    2014-01-01

    Carbon black was investigated to assess and quantify the possibility that nanoparticles might migrate out of plastic materials used in the food packaging industry. Two types of carbon black were incorporated in low-density polyethylene (LDPE) and polystyrene (PS) at 2.5% and 5.0% loading (w/w), and then subjected to migration studies. The samples were exposed to different food simulants according to European Union Plastics Regulation 10/2011, simulating long-term storage with aqueous and fatty foodstuffs. Asymmetric flow field-flow fractionation (AF4) coupled to a multi-angle laser light-scattering (MALLS) detector was used to separate, characterise and quantify the potential release of nanoparticles. The AF4 method was successful in differentiating carbon black from other matrix components, such as extracted polymer chains, in the migration solution. At a detection limit of 12 µg kg⁻¹, carbon black did not migrate from the packaging material into food simulants. The experimental findings are in agreement with theoretical considerations based on migration modelling. From both the experimental findings and theoretical considerations, it can be concluded that carbon black does not migrate into food once it is incorporated into a plastics food contact material. PMID:25105506

  18. Effect of molecular weight on the electrophoretic deposition of carbon black nanoparticles in moderately viscous systems.

    PubMed

    Modi, Satyam; Panwar, Artee; Mead, Joey L; Barry, Carol M F

    2013-08-01

    Electrophoretic deposition from viscous media has the potential to produce in-mold assembly of nanoparticles onto three-dimensional parts in high-rate, polymer melt-based processes like injection molding. The effects of the media's molecular weight on deposition behavior were investigated using a model system of carbon black and polystyrene in tetrahydrofuran. Increases in molecular weight reduced the electrophoretic deposition of the carbon black particles due to increases in suspension viscosity and preferential adsorption of the longer polystyrene chains on the carbon black particles. At low deposition times (≤5 s), only carbon black deposited onto the electrodes, but the deposition decreased with increasing molecular weight and the resultant increases in suspension viscosity. For longer deposition times, polystyrene codeposited with the carbon black, with the amount of polystyrene increasing with molecular weight and decreasing with greater charge on the polystyrene molecules. This deposition behavior suggests that use of lower molecular polymers and control of electrical properties will permit electrophoretic deposition of nanoparticles from polymer melts for high-rate, one-step fabrication of nano-optical devices, biochemical sensors, and nanoelectronics. PMID:23848316

  19. Migration of nanoparticles from plastic packaging materials containing carbon black into foodstuffs

    PubMed Central

    Bott, Johannes; Störmer, Angela; Franz, Roland

    2014-01-01

    Carbon black was investigated to assess and quantify the possibility that nanoparticles might migrate out of plastic materials used in the food packaging industry. Two types of carbon black were incorporated in low-density polyethylene (LDPE) and polystyrene (PS) at 2.5% and 5.0% loading (w/w), and then subjected to migration studies. The samples were exposed to different food simulants according to European Union Plastics Regulation 10/2011, simulating long-term storage with aqueous and fatty foodstuffs. Asymmetric flow field-flow fractionation (AF4) coupled to a multi-angle laser light-scattering (MALLS) detector was used to separate, characterise and quantify the potential release of nanoparticles. The AF4 method was successful in differentiating carbon black from other matrix components, such as extracted polymer chains, in the migration solution. At a detection limit of 12 µg kg−1, carbon black did not migrate from the packaging material into food simulants. The experimental findings are in agreement with theoretical considerations based on migration modelling. From both the experimental findings and theoretical considerations, it can be concluded that carbon black does not migrate into food once it is incorporated into a plastics food contact material. PMID:25105506

  20. Factors Controlling Black Carbon Deposition in Snow in the Arctic

    NASA Astrophysics Data System (ADS)

    Qi, L.; Li, Q.; He, C.; Li, Y.

    2015-12-01

    This study evaluates the sensitivity of black carbon (BC) concentration in snow in the Arctic to BC emissions, dry deposition and wet scavenging efficiency using a 3D global chemical transport model GEOS-Chem driven by meteorological field GEOS-5. With all improvements, simulated median BC concentration in snow agrees with observation (19.2 ng g-1) within 10%, down from -40% in the default GEOS-Chem. When the previously missed gas flaring emissions (mainly located in Russia) are included, the total BC emission in the Arctic increases by 70%. The simulated BC in snow increases by 1-7 ng g-1, with the largest improvement in Russia. The discrepancy of median BC in snow in the whole Arctic reduces from -40% to -20%. In addition, recent measurements of BC dry deposition velocity suggest that the constant deposition velocity of 0.03 cm s-1 over snow and ice used in the GEOS-Chem is too low. So we apply resistance-in-series method to calculate the dry deposition velocity over snow and ice and the resulted dry deposition velocity ranges from 0.03 to 0.24 cm s-1. However, the simulated total BC deposition flux in the Arctic and BC in snow does not change, because the increased dry deposition flux has been compensated by decreased wet deposition flux. However, the fraction of dry deposition to total deposition increases from 16% to 25%. This may affect the mixing of BC and snow particles and further affect the radative forcing of BC deposited in snow. Finally, we reduced the scavenging efficiency of BC in mixed-phase clouds to account for the effect of Wegener-Bergeron-Findeisen (WBF) process based on recent observations. The simulated BC concentration in snow increases by 10-100%, with the largest increase in Greenland (100%), Tromsø (50%), Alaska (40%), and Canadian Arctic (30%). Annual BC loading in the Arctic increases from 0.25 to 0.43 mg m-2 and the lifetime of BC increases from 9.2 to 16.3 days. This indicates that BC simulation in the Arctic is really sensitive to

  1. Evaluation of Black Carbon Estimations in Global Aerosol Models

    SciTech Connect

    Koch, D.; Schulz, M.; Kinne, Stefan; McNaughton, C. S.; Spackman, J. R.; Balkanski, Y.; Bauer, S.; Berntsen, T.; Bond, Tami C.; Boucher, Olivier; Chin, M.; Clarke, A. D.; De Luca, N.; Dentener, F.; Diehl, T.; Dubovik, O.; Easter, Richard C.; Fahey, D. W.; Feichter, J.; Fillmore, D.; Freitag, S.; Ghan, Steven J.; Ginoux, P.; Gong, S.; Horowitz, L.; Iversen, T.; Kirkevag, A.; Klimont, Z.; Kondo, Yutaka; Krol, M.; Liu, Xiaohong; Miller, R.; Montanaro, V.; Moteki, N.; Myhre, G.; Penner, J.; Perlwitz, Ja; Pitari, G.; Reddy, S.; Sahu, L.; Sakamoto, H.; Schuster, G.; Schwarz, J. P.; Seland, O.; Stier, P.; Takegawa, Nobuyuki; Takemura, T.; Textor, C.; van Aardenne, John; Zhao, Y.

    2009-11-27

    We evaluate black carbon (BC) model predictions from the AeroCom model intercomparison project by considering the diversity among year 2000 model simulations and comparing model predictions with available measurements. These model-measurement intercomparisons include BC surface and aircraft concentrations, aerosol absorption optical depth (AAOD) from AERONET and OMI retrievals and BC column estimations based on AERONET. In regions other than Asia, most models are biased high compared to surface concentration measurements. However compared with (column) AAOD or BC burden retreivals, the models are generally biased low. The average ratio of model to retrieved AAOD is less than 0.7 in South American and 0.6 in African biomass burning regions; both of these regions lack surface concentration measurements. In Asia the average model to observed ratio is 0.6 for AAOD and 0.5 for BC surface concentrations. Compared with aircraft measurements over the Americas at latitudes between 0 and 50N, the average model is a factor of 10 larger than observed, and most models exceed the measured BC standard deviation in the mid to upper troposphere. At higher latitudes the average model to aircraft BC is 0.6 and underestimate the observed BC loading in the lower and middle troposphere associated with springtime Arctic haze. Low model bias for AAOD but overestimation of surface and upper atmospheric BC concentrations at lower latitudes suggests that most models are underestimating BC absorption and should improve estimates for refractive index, particle size, and optical effects of BC coating. Retrieval uncertainties and/or differences with model diagnostic treatment may also contribute to the model-measurement disparity. Largest AeroCom model diversity occurred in northern Eurasia and the remote Arctic, regions influenced by anthropogenic sources. Changing emissions, aging, removal, or optical properties within a single model generated a smaller change in model predictions than the

  2. Black carbon and the Himalayan cryosphere: A review

    NASA Astrophysics Data System (ADS)

    Gertler, Charles G.; Puppala, Siva Praveen; Panday, Arnico; Stumm, Dorothea; Shea, Joseph

    2016-01-01

    The Himalayan cryosphere borders global hotspots for emissions of black carbon (BC), a carbonaceous aerosol with a short atmospheric lifespan and potentially significant impacts on glaciers and snow cover. BC in the atmosphere absorbs radiation efficiently, leading to localized positive climate forcing. BC may also be deposited onto snow and ice surfaces, thereby changing their albedo. This review presents up-to-date observational data of BC in the atmosphere and in snow and ice, as well as its effects on the cryosphere in the Hindu-Kush-Himalayan (HKH) region along the northern edge of South Asia. Significant spatial variation exists in the measured concentrations of BC in the atmosphere and cryosphere. A strong seasonal pattern exists, with highest concentrations in the pre-monsoon and lowest during the monsoon. Existing observations show bias towards certain areas, with a noticeable lack of measurements on the south side of the Himalaya. Significant uncertainty persists in the emissions estimates of BC in the HKH region, with a standard deviation of regional emissions from various emission inventories of 0.5150 × 10-9 kg m-2 s-1, or 47.1% of the mean (1.0931 × 10-9 kg m-2 s-1). This and other uncertainties, including poor model resolution, imprecision in deposition modeling, and incongruities among measurement types, propagate through simulations of BC concentration in atmosphere and cryosphere. Modeled atmospheric concentrations can differ from observations by as much as a factor of three with no systematic bias, and modeled concentrations in snow and ice can differ from observations by a factor of 60 in certain regions. In the Himalaya, estimates of albedo change due to BC range from about 2 to 10%, estimates of direct radiative forcing due to BC in the atmosphere from (-2)-7 W m-2, and surface forcing estimates from 0 to 28 W m-2, though every forcing estimate uses its own definition, with varying degrees of complexity and numbers of feedbacks. We find the

  3. Heavy duty piezoresistivity induced strain sensing natural rubber/carbon black nanocomposites reinforced with different carbon nanofillers

    NASA Astrophysics Data System (ADS)

    He, Qingliang; Yuan, Tingting; Zhang, Xi; Guo, Shimei; Liu, Jingjing; Liu, Jiurong; Liu, Xinyu; Sun, Luyi; Wei, Suying; Guo, Zhanhu

    2014-09-01

    Durable piezoresistive effects of natural rubber nanocomposites have been demonstrated, i.e., with stable and reversible electrical resistance change within the tested 3000 cycles upon applying a small compressive strain (˜16.7%) under a relatively high frequency (0.5 Hz, 2 s/cycle). This unique function was achieved for the first time by combining carbon nanotubes and carbon nanofibers with natural rubber composites pretreated with carbon black. Even though the combination of different carbon nanomaterials, such as graphene nanosheets and carbon nanotubes, can improve the dispersion quality of both the nanostructures in solution or in polymer matrices, this type of synergistic effect between carbon nanotubes and carbon nanofibers in producing stable and reversible piezoresistive effect has been rarely reported. Besides, the strong reinforcement (compressive stress at a maximum strain of 16.7% was increased from 12.6 for untreated to 18.5 MPa for the natural rubber/carbon black composites treated with a combination of 1.0 wt% carbon nanotubes and 1.0 wt% carbon nanofibers) makes the as-prepared composites promising for heavy duty pressure sensors, i.e., healthy motion monitoring of industrial machinery vibrations.

  4. Effect of Thermal Aging on the Viscosity of Suspensions of Carbon Black in Polybutadiene

    NASA Astrophysics Data System (ADS)

    von Meerwall, E.; Hong, M. P.; Kelley, F. N.

    1998-05-01

    We have studied the effects of aging time and temperature on the viscosity of an hydroxyl-terminated polybutadiene (HTPB) containing suspended carbon black. After surface application such HTPB suspensions are crosslinked to form liners in solid rocket motors. The suspension viscosity decreases with aging time, more rapidly at higher temperatures, and approaches a lower asymptote which depends on filler fraction. Heat-drying the carbon black before incorporation lessens the magnitude of this effect and accelerates the approach to equilibrium; moistening the black enlarges it and delays the approach. We conclude that this effect is related to the moisture adsorbed on the black particles. The water is not completely soluble in the polymer, resulting in reversible emulsification, and is driven off during aging. A variety of secondary experiments performed (use of a wetting agent, centrifugation, dc electrical resistivity, NMR spin-spin relaxation and self-diffusion, optical microscopy) eliminate several other likely explanations.

  5. Long-range transported dissolved organic matter, ions and black carbon deposited on Central Asian snow covered glaciers

    NASA Astrophysics Data System (ADS)

    Schmale, Julia; Kang, Shichang; Peltier, Richard

    2014-05-01

    Ninety percent of the Central Asian population depend on water precipitated in the mountains stored in glaciers and snow cover. Accelerated melting of the snow and ice can be induced by the deposition of airborne impurities such as mineral dust, black carbon and co-emitted species leading to significant reductions of the surface albedo. However, Central Asia is a relatively understudied region and data on the source regions, chemical and microphysical characteristics as well as modelling studies of long-range transported air pollution and dust to the Tien Shan mountains is very scarce. We studied the atmospheric aerosol deposited most likely between summer 2012 and summer 2013on three different glaciers in the Kyrgyz Republic. Samples were taken from four snow pits on the glaciers Abramov (2 pits, 39.59 °N, 71.56 °E, 4390 m elevation, 240 cm deep, and 39.62°N, 71.52 °E, 4275 m elevation, 125 cm deep), Ak-Shiirak (41.80 °N, 78.18 °E, 4325 m elevation, 75 cm deep) and Suek (41.78 °N, 77.75 °E, 4341 m elevation, 200 cm deep). The latter two glaciers are located roughly within 6 and 38 km of an operating gold mine. The snow was analyzed for black carbon, ions, metals and organic carbon. We here focus on the results of inorganic ion measurements and organic carbon speciation based on analysis with an Aerodyne high-resolution time-of-flight aerosol spectrometer (HR-ToF-AMS) and potential pollution sources that can be deduced from the chemical information as well as back trajectories. Average contributions of snow impurities measured by the HR-ToF-AMS were dominated by organic carbon. Relative concentrations of organic carbon, sulfate, nitrate and ammonium in snow were 86 %, 3 %, 9 % and 2 % respectively for Abramov, 92 %, 1 %, 5 % and 1 % for Suek, and 95 %, 1 %, 3 % and 1 % for Ak-Shiirak. Generally, impurities on Suek and Ak-Shiirak were three and five times higher than on Abramov. Mass concentrations of organic carbon were on average 6 times higher in samples

  6. Electrical transport in carbon black-epoxy resin composites at different temperatures

    NASA Astrophysics Data System (ADS)

    Macutkevic, J.; Kuzhir, P.; Paddubskaya, A.; Maksimenko, S.; Banys, J.; Celzard, A.; Fierro, V.; Bistarelli, S.; Cataldo, A.; Micciulla, F.; Bellucci, S.

    2013-07-01

    Results of broadband electric/dielectric properties of different surface area—carbon black/epoxy resin composites above the percolation threshold are reported in a wide temperature range (25-500 K). At higher temperatures (above 400 K), the electrical conductivity of composites is governed by electrical transport in polymer matrix and current carriers tunneling from carbon black clusters to polymer matrix. The activation energy of such processes decreases when the carrier concentration increases, i.e., with the increase of carbon black concentration. At lower temperatures, the electrical conductivity is governed by electron tunneling and hopping. The electrical conductivity and dielectric permittivity of composites strongly decrease after annealing composites at high temperatures (500 K); at the same time potential barrier for carriers tunneling strongly increases. All the observed peculiarities can be used for producing effective low-cost materials on the basis of epoxy resin working at different temperatures for electrical applications.

  7. A method for monitoring mass concentration of black carbon particulate matter using photothermal interferometry.

    PubMed

    Li, Baosheng; Wang, Yicheng; Li, Zhengqiang

    2016-03-01

    A method for measurements of mass concentration of black carbon particulate matter (PM) is proposed based on photothermal interferometry (PTI). A folded Jamin photothermal interferometer was used with a laser irradiation of particles deposited on a filter paper. The black carbon PM deposited on the filter paper was regarded as a film while the quartz filter paper was regarded as a substrate to establish a mathematical model for measuring the mass concentration of PM using a photothermal method. The photothermal interferometry system was calibrated and used to measure the atmospheric PM concentration corresponding to different dust-treated filter paper. The measurements were compared to those obtained using β ray method and were found consistent. This method can be particularly relevant to polluted atmospheres where PM is dominated by black carbon. PMID:26527346

  8. Historical Black Carbon Emission of South Asia recorded in the Southeastern Tibetan Glacier

    NASA Astrophysics Data System (ADS)

    Wang, M.; Xu, B.

    2012-12-01

    South Asian black carbon (BC) emission draws much attention in recent years as its accelerated increasing tendency and the important role of BC for human health, climate modification, and glacier retreat. We present the measurements of the elemental carbon (EC) and organic carbon (OC) covering the time period of 1956-2006 in a high resolution ice core from the southeastern Tibetan Plateau dominated by South Asian emission. The variation tendencies of black soot concentrations are consistent with South Asian emission inventory and fossil fuel consumption. The fossil fuel combustion might be largely responsible for the increasing trend of black soot emission, but biomass-burning share has been increased since the middle of 1990s revealed by the continued decrease of EC/OC ratio.

  9. Aerosol organic carbon to black carbon ratios: Analysis ofpublished data and implications for climate forcing

    SciTech Connect

    Novakov, T.; Menon, S.; Kirchstetter, T.W.; Koch, D.; Hansen, J.E.

    2005-07-11

    Measurements of organic carbon (OC) and black carbon (BC)concentrations over a variety of locations worldwide, have been analyzed to infer the spatial distributions of the ratios of OC to BC. Since these ratios determine the relative amounts of scattering and absorption, they are often used to estimate the radiative forcing due to aerosols. An artifact in the protocol for filter measurements of OC has led to widespread overestimates of the ratio of OC to BC in atmospheric aerosols. We developed a criterion to correct for this artifact and analyze corrected OC to BC ratios. The OC to BC ratios, ranging from 1.3to 2.4, appear relatively constant and are generally unaffected by seasonality, sources or technology changes, at the locations considered here. The ratios compare well with emission inventories over Europe and China but are a factor of two lower in other regions. The reduced estimate for OC/BC in aerosols strengthens the argument that reduction of soot emissions maybe a useful approach to slow global warming.

  10. IMPORTANCE OF BLACK CARBON IN DISTRIBUTION AND BIOACCUMULATION MODELS OF POLYCYCLIC AROMATIC HYDROCARBONS IN CONTAMINATED MARINE SEDIMENTS

    EPA Science Inventory

    The roles and relative importance of nonpyrogenic organic carbon (NPOC) and black carbon (BC) as binding phases of polycyclic aromatic hydrocarbons (PAHs) were assessed by their ability to estimate pore water concentrations and biological uptake in various marine sediments. Sedim...

  11. Airborne detection of diffuse carbon dioxide emissions at Mammoth Mountain, California

    USGS Publications Warehouse

    Gerlach, T.M.; Doukas, M.P.; McGee, K.A.; Kessler, R.

    1999-01-01

    We report the first airborne detection of CO2 degassing from diffuse volcanic sources. Airborne measurement of diffuse CO2 degassing offers a rapid alternative for monitoring CO2 emission rates at Mammoth Mountain. CO2 concentrations, temperatures, and barometric pressures were measured at ~2,500 GPS-referenced locations during a one-hour, eleven-orbit survey of air around Mammoth Mountain at ~3 km from the summit and altitudes of 2,895-3,657 m. A volcanic CO2 anomaly 4-5 km across with CO2 levels ~1 ppm above background was revealed downwind of tree-kill areas. It contained a 1-km core with concentrations exceeding background by >3 ppm. Emission rates of ~250 t d-1 are indicated. Orographic winds may play a key role in transporting the diffusely degassed CO2 upslope to elevations where it is lofted into the regional wind system.We report the first airborne detection of CO2 degassing from diffuse volcanic sources. Airborne measurement of diffuse CO2 degassing offers a rapid alternative for monitoring CO2 emission rates at Mammoth Mountain. CO2 concentrations, temperatures, and barometric pressures were measured at approximately 2,500 GPS-referenced locations during a one-hour, eleven-orbit survey of air around Mammoth Mountain at approximately 3 km from the summit and altitudes of 2,895-3,657 m. A volcanic CO2 anomaly 4-5 km across with CO2 levels approximately 1 ppm above background was revealed downwind of tree-kill areas. It contained a 1-km core with concentrations exceeding background by >3 ppm. Emission rates of approximately 250 t d-1 are indicated. Orographic winds may play a key role in transporting the diffusely degassed CO2 upslope to elevations where it is lofted into the regional wind system.

  12. Estimation of black carbon content for biomass burning aerosols from multi-channel Raman lidar data

    NASA Astrophysics Data System (ADS)

    Talianu, Camelia; Marmureanu, Luminita; Nicolae, Doina

    2015-04-01

    Biomass burning due to natural processes (forest fires) or anthropical activities (agriculture, thermal power stations, domestic heating) is an important source of aerosols with a high content of carbon components (black carbon and organic carbon). Multi-channel Raman lidars provide information on the spectral dependence of the backscatter and extinction coefficients, embedding information on the black carbon content. Aerosols with a high content of black carbon have large extinction coefficients and small backscatter coefficients (strong absorption), while aerosols with high content of organic carbon have large backscatter coefficients (weak absorption). This paper presents a method based on radiative calculations to estimate the black carbon content of biomass burning aerosols from 3b+2a+1d lidar signals. Data is collected at Magurele, Romania, at the cross-road of air masses coming from Ukraine, Russia and Greece, where burning events are frequent during both cold and hot seasons. Aerosols are transported in the free troposphere, generally in the 2-4 km altitude range, and reaches the lidar location after 2-3 days. Optical data are collected between 2011-2012 by a multi-channel Raman lidar and follows the quality assurance program of EARLINET. Radiative calculations are made with libRadTran, an open source radiative model developed by ESA. Validation of the retrievals is made by comparison to a co-located C-ToF Aerosol Mass Spectrometer. Keywords: Lidar, aerosols, biomass burning, radiative model, black carbon Acknowledgment: This work has been supported by grants of the Romanian National Authority for Scientific Research, Programme for Research- Space Technology and Advanced Research - STAR, project no. 39/2012 - SIAFIM, and by Romanian Partnerships in priority areas PNII implemented with MEN-UEFISCDI support, project no. 309/2014 - MOBBE

  13. The Arctic is especially sensitive to black carbon emissions from within the region

    NASA Astrophysics Data System (ADS)

    Sand, M.; Berntsen, T.; Seland; Kristjansson, J.

    2013-12-01

    The Arctic has warmed twice as fast as the global average over the past century and is likely to be especially sensitive to black carbon aerosols. Black carbon warm the air by absorbing solar radiation and can promote snow melt when deposited in snow. In this study we address the question of how sensitive the Arctic climate is to black carbon emitted within the Arctic compared to black carbon emitted at mid-latitudes. We consider the emission-climate response spectrum and present a set of experiments using a coupled global climate model. The climate model includes a snow model to simulate the climate effect of BC deposited on snow. A new emission data set including BC emissions from flaring and a seasonal variation in the domestic sector has been used. The dominating BC emissions in the Arctic is related to oil and gas fields in north western Russia. We find that most of the BC-induced warming in the Arctic is caused by black carbon deposited on snow, rather than in the atmosphere. Black carbon emitted in the Arctic is more likely to get deposited at the surface since most of the concentrations stay at lower altitudes. Especially during winter, BC emitted in North-Eurasia is transported into the high Arctic at low altitudes. We find that BC emitted within the Arctic has an almost 5-times larger Arctic surface temperature response (per unit of emitted mass) compared to emissions at mid-latitudes. Today there are few within-Arctic sources of BC, but the emissions are expected to grow due to increased human activity in the Arctic. There is a great need to improve cleaner technologies if further development is to take place in the Arctic, especially since the Arctic has a significantly higher sensitivity to BC emitted within the Arctic compared to BC emitted at mid-latitudes.

  14. Commuter exposure to black carbon, carbon monoxide, and noise in the mass transport khlong boats of Bangkok, Thailand

    NASA Astrophysics Data System (ADS)

    Ziegler, A. D.; Velasco, E.; Ho, K. J.

    2013-12-01

    Khlong (canal) boats are a unique mass transport alternative in the congested city of Bangkok. Canals and rivers provide exclusive transit-ways for reducing the commuting time of thousands of city residents daily. However, as a consequence of the service characteristics and boats design and state of repair, they can represent a potential public health risk and an important source of black carbon and greenhouse gases. This work quantifies commuter exposure to black carbon, CO and noise when waiting for and travelling in these diesel fueled boats. Exposure to toxic pollutants and acute noise is similar or worse than for other transportation modes. Mean black carbon concentrations observed at one busy pier and along the main canal were much higher than ambient concentrations at sites impacted by vehicular traffic. Concentrations of CO were similar to those reported for roadside areas of Bangkok. The equivalent continuous sound levels registered at the landing pier were similar to those reported for roadsides, but values recorded inside the boats were significantly higher. We believe that the boat service is a viable alternative mode of mass transport, but public safety could be improved to provide a high quality service, comparable to modern rail systems or emerging bus rapid transit systems. These investments would also contribute to reduce the emission of black carbon and other greenhouse and toxic pollutants.

  15. The use of airborne laser scanning to develop a pixel-based stratification for a verified carbon offset project

    PubMed Central

    2011-01-01

    Background The voluntary carbon market is a new and growing market that is increasingly important to consider in managing forestland. Monitoring, reporting, and verifying carbon stocks and fluxes at a project level is the single largest direct cost of a forest carbon offset project. There are now many methods for estimating forest stocks with high accuracy that use both Airborne Laser Scanning (ALS) and high-resolution optical remote sensing data. However, many of these methods are not appropriate for use under existing carbon offset standards and most have not been field tested. Results This paper presents a pixel-based forest stratification method that uses both ALS and optical remote sensing data to optimally partition the variability across an ~10,000 ha forest ownership in Mendocino County, CA, USA. This new stratification approach improved the accuracy of the forest inventory, reduced the cost of field-based inventory, and provides a powerful tool for future management planning. This approach also details a method of determining the optimum pixel size to best partition a forest. Conclusions The use of ALS and optical remote sensing data can help reduce the cost of field inventory and can help to locate areas that need the most intensive inventory effort. This pixel-based stratification method may provide a cost-effective approach to reducing inventory costs over larger areas when the remote sensing data acquisition costs can be kept low on a per acre basis. PMID:22004847

  16. Validating a nondestructive optical method for apportioning colored particulate matter into black carbon and additional components

    NASA Astrophysics Data System (ADS)

    Yan, Beizhan; Kennedy, Daniel; Miller, Rachel L.; Cowin, James P.; Jung, Kyung-hwa; Perzanowski, Matt; Balletta, Marco; Perera, Federica P.; Kinney, Patrick L.; Chillrud, Steven N.

    2011-12-01

    Exposure of black carbon (BC) is associated with a variety of adverse health outcomes. A number of optical methods for estimating BC on Teflon filters have been adopted but most assume all light absorption is due to BC while other sources of colored particulate matter exist. Recently, a four-wavelength-optical reflectance measurement for distinguishing second hand cigarette smoke (SHS) from soot-BC was developed (Brook et al., 2010; Lawless et al., 2004). However, the method has not been validated for soot-BC nor SHS and little work has been done to look at the methodological issues of the optical reflectance measurements for samples that could have SHS, BC, and other colored particles. We refined this method using a lab-modified integrating sphere with absorption measured continuously from 350 nm to 1000 nm. Furthermore, we characterized the absorption spectrum of additional components of particulate matter (PM) on PM 2.5 filters including ammonium sulfate, hematite, goethite, and magnetite. Finally, we validate this method for BC by comparison to other standard methods. Use of synthesized data indicates that it is important to optimize the choice of wavelengths to minimize computational errors as additional components (more than 2) are added to the apportionment model of colored components. We found that substantial errors are introduced when using 4 wavelengths suggested by Lawless et al. to quantify four substances, while an optimized choice of wavelengths can reduce model-derived error from over 10% to less than 2%. For environmental samples, the method was sensitive for estimating airborne levels of BC and SHS, but not mass loadings of iron oxides and sulfate. Duplicate samples collected in NYC show high reproducibility (points consistent with a 1:1 line, R2 = 0.95). BC data measured by this method were consistent with those measured by other optical methods, including Aethalometer and Smoke-stain Reflectometer (SSR); although the SSR looses sensitivity at

  17. Validating a nondestructive optical method for apportioning colored particulate matter into black carbon and additional components

    PubMed Central

    Yan, Beizhan; Kennedy, Daniel; Miller, Rachel L.; Cowin, James P.; Jung, Kyung-hwa; Perzanowski, Matt; Balletta, Marco; Perera, Federica P.; Kinney, Patrick L.; Chillrud, Steven N.

    2011-01-01

    Exposure of black carbon (BC) is associated with a variety of adverse health outcomes. A number of optical methods for estimating BC on Teflon filters have been adopted but most assume all light absorption is due to BC while other sources of colored particulate matter exist. Recently, a four-wavelength-optical reflectance measurement for distinguishing second hand cigarette smoke (SHS) from soot-BC was developed (Brook et al., 2010; Lawless et al., 2004). However, the method has not been validated for soot-BC nor SHS and little work has been done to look at the methodological issues of the optical reflectance measurements for samples that could have SHS, BC, and other colored particles. We refined this method using a lab-modified integrating sphere with absorption measured continuously from 350 nm to 1000 nm. Furthermore, we characterized the absorption spectrum of additional components of particulate matter (PM) on PM2.5 filters including ammonium sulfate, hematite, goethite, and magnetite. Finally, we validate this method for BC by comparison to other standard methods. Use of synthesized data indicates that it is important to optimize the choice of wavelengths to minimize computational errors as additional components (more than 2) are added to the apportionment model of colored components. We found that substantial errors are introduced when using 4 wavelengths suggested by Lawless et al. to quantify four substances, while an optimized choice of wavelengths can reduce model-derived error from over 10% to less than 2%. For environmental samples, the method was sensitive for estimating airborne levels of BC and SHS, but not mass loadings of iron oxides and sulfate. Duplicate samples collected in NYC show high reproducibility (points consistent with a 1:1 line, R2 = 0.95). BC data measured by this method were consistent with those measured by other optical methods, including Aethalometer and Smoke-stain Reflectometer (SSR); although the SSR looses sensitivity at

  18. Aerosol Absorption by Black Carbon and Dust: Implications of Climate Change and Air Quality in Asia

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2010-01-01

    Atmospheric aerosol distributions from 2000 to 2007 are simulated with the global model GOCART to attribute light absorption by aerosol to its composition and sources. We show the seasonal and interannual variations of absorbing aerosols in the atmosphere over Asia, mainly black carbon and dust. and their linkage to the changes of anthropogenic and dust emissions in the region. We compare our results with observations from satellite and ground-based networks, and estimate the importance of black carbon and dust on regional climate forcing and air quality.

  19. Bio-lnspired dielectric elastomer actuator with AgNWs coated on carbon black electrode.

    PubMed

    Jun, K W; Lee, J M; Lee, J Y; Ohl, I K

    2014-10-01

    Bio-inspired dielectric elastomer actuators with AgNW-coated carbon black electrodes were developed in this study. The novel elastomer actuators show large in-plane deformations by electrical stimulation through the both electrodes. When a certain input voltage is applied to the elastomer electrode, the electrostatic force between cathode and anode electrodes compress the dielectric elastomer film, resulting large in in-plane direction deformation. The expanded area of the circular actuation device under 70 mV/m electric field was measured up to 50% due to a synergistic effect of highly conductive AgNW network and ultrahigh capacitance of carbon black electrodes. PMID:25942813

  20. Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring

    NASA Technical Reports Server (NTRS)

    Ryan, M. A.; Shevade, A. V.; Zhou, H.; Homer, M. L.

    2004-01-01

    An electronic nose that uses an array of 32 polymer-carbon black composite sensors has been developed, trained, and tested. By selecting a variety of chemical functionalities in the polymers used to make sensors, it is possible to construct an array capable of identifying and quantifying a broad range of target compounds, such as alcohols and aromatics, and distinguishing isomers and enantiomers (mirror-image isomers). A model of the interaction between target molecules and the polymer-carbon black composite sensors is under development to aid in selecting the array members and to enable identification of compounds with responses not stored in the analysis library.

  1. Bounding the Role of Black Carbon in the Climate System: a Scientific Assessment

    NASA Technical Reports Server (NTRS)

    Bond, T. C.; Doherty, S. J.; Fahey, D. W.; Forster, P. M.; Bernsten, T.; DeAngelo, B. J.; Flanner, M. G.; Ghan, S.; Karcher, B.; Koch, D.; Kinne, S.; Kondo, Y.; Quinn, P. K.; Sarofim, M. C.; Schultz, M. G.; Schulz, M.; Venkataraman, C.; Zhang, H.; Zhang, S.; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, J. P.; Shindell, D.; Storelvmo, T.; Warren, S. G.; Zender, C. S.

    2013-01-01

    Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg/yr in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W/sq m with 90% uncertainty bounds of (+0.08, +1.27)W/sq m. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W/sq m. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W/sq m with 90% uncertainty bounds of +0.17 to +2.1 W/sq m. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing

  2. Bounding the Role of Black Carbon in the Climate System: A Scientific Assessment

    SciTech Connect

    Bond, Tami C.; Doherty, Sarah J.; Fahey, D. W.; Forster, Piers; Berntsen, T.; DeAngelo, B. J.; Flanner, M. G.; Ghan, Steven J.; Karcher, B.; Koch, Dorothy; Kinne, Stefan; Kondo, Yutaka; Quinn, P. K.; Sarofim, Marcus; Schultz, Martin; Schulz, M.; Venkataraman, C.; Zhang, Hua; Zhang, Shiqiu; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, Joshua P.; Shindell, Drew; Storelvmo, Trude; Warren, Stephen G.; Zender, C. S.

    2013-06-06

    Black carbon aerosol plays a unique and important role in Earth’s climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. Predominant sources are combustion related; namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr-1 in the year 2000 with an uncertainty range of 2000 to 29000. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption, influence on liquid, mixed-phase, and ice clouds, and deposition on snow and ice. These effects are calculated with models, but when possible, they are evaluated with both microphysical measurements and field observations. Global atmospheric absorption attributable to black carbon is too low in many models, and should be increased by about about 60%. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of black carbon is +0.43 W m-2 with 90% uncertainty bounds of (+0.17, +0.68) W m-2. Total direct forcing by all black carbon sources in the present day is estimated as +0.49 (+0.20, +0.76) W m-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings and their rapid responses and feedbacks. The best estimate of industrial-era (1750 to 2005) climate forcing of black carbon through all forcing mechanisms is +0.77 W m-2 with 90% uncertainty bounds of +-0.06 to +1.53 W m-2. Thus, there is a 96% probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. With a value of +0.77 W m-2, black carbon is likely the second

  3. Relating black carbon content to reduction of snow albedo

    NASA Astrophysics Data System (ADS)

    Brandt, R. E.; Warren, S. G.; Clarke, A. D.

    2011-12-01

    In remote snow of the Northern Hemisphere, the levels of soot pollution are in the parts-per-billion (ppb) range, where the effect on albedo is at the level of a few percent. A reduction of albedo by 1-2% is significant for climate but is difficult to detect experimentally, because snow albedo depends on several other variables. In our work to quantify the climatic effect of black carbon (BC) in snow, we therefore do not directly measure the albedo reduction. Instead, we use a two-step procedure: (1) We collect snow samples, melt and filter them, and analyze the filters spectrophotometrically for BC concentration. (2) We use the BC amount from the filter measurement, together with snow grain size, in a radiative transfer model to compute the albedo reduction. Our radiative transfer model uses the discrete ordinates algorithm DISORT 2.0. We have chosen a representative BC size distribution and optical constants, and have incorporated those of mineral dust as well. While a given mass of BC causes over an order of magnitude more snow albedo reduction compared to dust, a snowpack containing dust mutes the albedo-reducing effect of BC. Because the computed reduction of snow albedo is model-based, it requires experimental verification. We doubt that direct measurement of albedo-reduction will be feasible in nature, because of the vertical variation of both snow grain size and soot content, and because the natural soot content is small. We conclude that what is needed is an artificial snowpack, with uniform grain size and large uniform soot content (ppm not ppb), to produce a large signal on albedo. We have chosen to pursue this experiment outdoors rather than in the laboratory, for the following reasons: (1) The snowpack in the field of view is uniformly illuminated if the source of radiation is the Sun. (2) Visible radiation penetrates into the snow, so photons emerge horizontally distant from where they entered. In the limited width of a laboratory snowpack, radiation

  4. An index-based approach to assessing recalcitrance and soil carbon sequestration potential of engineered black carbons (biochars).

    PubMed

    Harvey, Omar R; Kuo, Li-Jung; Zimmerman, Andrew R; Louchouarn, Patrick; Amonette, James E; Herbert, Bruce E

    2012-02-01

    The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R(50), for assessing biochar quality for carbon sequestration is proposed. The R(50) is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R(50), with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiable relationship between R(50) and biochar recalcitrance. As presented here, the R(50) is immediately applicable to pre-land application screening of biochars into Class A (R(50) ≥ 0.70), Class B (0.50 ≤ R(50) < 0.70) or Class C (R(50) < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, whereas Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R(50), to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars. PMID:22242866

  5. An Index-Based Approach to Assessing Recalcitrance and Soil Carbon Sequestration Potential of Engineered Black Carbons (Biochars)

    SciTech Connect

    Harvey, Omar R.; Kuo, Li-Jung; Zimmerman, Andrew R.; Louchouarn, Patrick; Amonette, James E.; Herbert, Bruce

    2012-01-10

    The ability of engineered black carbons (or biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R{sub 50}, for assessing biochar quality for carbon sequestration is proposed. The R{sub 50} is based on the relative thermal stability of a given biochar to that of graphite and was developed and evaluated with a variety of biochars (n = 59), and soot-like black carbons. Comparison of R{sub 50}, with biochar physicochemical properties and biochar-C mineralization revealed the existence of a quantifiable relationship between R{sub 50} and biochar recalcitrance. As presented here, the R{sub 50} is immediately applicable to pre-land application screening of biochars into Class A (R{sub 50} {>=} 0.70), Class B (0.50 {<=} R{sub 50} < 0.70) or Class C (R{sub 50} < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C biochars would have carbon sequestration potential comparable to soot/graphite and uncharred plant biomass, respectively, while Class B biochars would have intermediate carbon sequestration potential. We believe that the coupling of the R{sub 50}, to an index-based degradation, and an economic model could provide a suitable framework in which to comprehensively assess soil carbon sequestration in biochars.

  6. Regional prediction of soil organic carbon content over temperate croplands using visible near-infrared airborne hyperspectral imagery and synchronous field spectra

    NASA Astrophysics Data System (ADS)

    Vaudour, E.; Gilliot, J. M.; Bel, L.; Lefevre, J.; Chehdi, K.

    2016-07-01

    This study aimed at identifying the potential of Vis-NIR airborne hyperspectral AISA-Eagle data for predicting the topsoil organic carbon (SOC) content of bare cultivated soils over a large peri-urban area (221 km2) with both contrasted soils and SOC contents, located in the western region of Paris, France. Soil types comprised haplic luvisols, calcaric cambisols and colluvic cambisols. Airborne AISA-Eagle data (400-1000 nm, 126 bands) with 1 m-resolution were acquired on 17 April 2013 over 13 tracks. Tracks were atmospherically corrected then mosaicked at a 2 m-resolution using a set of 24 synchronous field spectra of bare soils, black and white targets and impervious surfaces. The land use identification system layer (RPG) of 2012 was used to mask non-agricultural areas, then calculation and thresholding of NDVI from an atmospherically corrected SPOT image acquired the same day enabled to map agricultural fields with bare soil. A total of 101 sites sampled either in 2013 or in the 3 previous years and in 2015 were identified as bare by means of this map. Predictions were made from the mosaic AISA spectra which were related to topsoil SOC contents by means of partial least squares regression (PLSR). Regression robustness was evaluated through a series of 1000 bootstrap data sets of calibration-validation samples, considering 74 sites outside cloud shadows only, and different sampling strategies for selecting calibration samples. Validation root-mean-square errors (RMSE) were comprised between 3.73 and 4.49 g Kg-1 and were ∼4 g Kg-1 in median. The most performing models in terms of coefficient of determination (R2) and Residual Prediction Deviation (RPD) values were the calibration models derived either from Kennard-Stone or conditioned Latin Hypercube sampling on smoothed spectra. The most generalizable model leading to lowest RMSE value of 3.73 g Kg-1 at the regional scale and 1.44 g Kg-1 at the within-field scale and low bias was the cross-validated leave

  7. Eight combinatorial stacks of three layers of carbon black/PVA-carbon black/EVA composite as a vapor detector array.

    PubMed

    Setasuwon, Paisan; Menbangpung, Laongdao; Sahasithiwat, Somboon

    2008-01-01

    Eight specimens of combinatorial stacking of 3 layers of carbon black/PVA-carbon black/EVA composite were prepared on substrate with interdigitated electrode. They were subjected to 15 solvent vapors with dielectric constants from 2-80,and their responses were processed for calculation of resolution factor (RF). If the detector responses are assumed to have a normal distribution, RF values of 1.0, 2.0, and 3.0 indicate the 76, 92, and 98% confidence, respectively, of correctly identifying one analyte from the other of a specific pair. Of the possible 105 pairs, 99 pairs have RF values of more than 3, 5 pairs have RF values of more than 1, and only one pair has an RF value of less than 1. The resolution factor was affected by both the dielectric constant and boiling point of tested solvents. Employing Fisher linear discrimination improves all RF values greater than 3, making confidence in resolving the pair reach almost 100%. Contributions from each combination were studied, and it was shown that diversity by combinatorial stacking is essential to the improvement of RF value. All of these capabilities are derived from combinatorial stacking of 3 layers of just two simple carbon black/polymer composites. PMID:18855459

  8. Effect of the secondary organic aerosol coatings on black carbon water uptake, cloud condensation nuclei activity, and particle collapse

    EPA Science Inventory

    The ability of black carbon aerosols to absorb water and act as a cloud condensation nuclei (CCN) directly controls their lifetime in the atmosphere as well as their impact on cloud formation, thus impacting the earth’s climate. Black carbon emitted from most combustion pro...

  9. Black Ink of Activated Carbon Derived From Palm Kernel Cake (PKC)

    NASA Astrophysics Data System (ADS)

    Selamat, M. H.; Ahmad, A. H.

    2009-06-01

    Recycling the waste from natural plant to produce useful end products will benefit many industries and help preserve the environment. The research reported in this paper is an investigation on the use of the natural waste of palm kernel cake (PKC) to produce carbon residue as a black carbon for pigment source by using pyrolysis process. The activated carbons (AC) is produced in powder form using ball milling process. Rheological spectra in ink is one of quality control process in determining its performance properties. Findings from this study will help expand the scientific knowledge-base for black ink production and formulation base on PKC. Various inks with different weight percentage compositions of AC will be made and tested against its respective rheological properties in order to determine ideal ink printing system. The items in the formulation used comprised of organic and bio-waste materials with added additive to improve the quality of the black ink. Modified Polyurethane was used as binder. The binder's properties highlighted an ideal vehicle to be applied for good black ink opacity performance. The rheological behaviour is a general foundation for ink characterization where the wt% of AC-PKC resulted in different pseudoplastic behaviors, including the Newtonian behavior. The result found that Newtonian field was located in between 2 wt% and 10 wt% of AC-PKC composition with binder. Mass spectroscopy results shown that the carbon content in PKC is high and very suitable for black performance. In the ageing test, the pigment of PKC perform fairly according to the standard pigment of Black carbon (CB) of ferum oxide pigment. The contact angle for substrate's wettability of the ink system shown a good angle proven to be a water resistive coating on paper subtrates; an advantage of the PKC ink pigment performance.

  10. Bounding the role of black carbon in the climate system: A scientific assessment

    NASA Astrophysics Data System (ADS)

    Bond, T. C.; Doherty, S. J.; Fahey, D. W.; Forster, P. M.; Berntsen, T.; Deangelo, B. J.; Flanner, M. G.; Ghan, S.; KäRcher, B.; Koch, D.; Kinne, S.; Kondo, Y.; Quinn, P. K.; Sarofim, M. C.; Schultz, M. G.; Schulz, M.; Venkataraman, C.; Zhang, H.; Zhang, S.; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, J. P.; Shindell, D.; Storelvmo, T.; Warren, S. G.; Zender, C. S.

    2013-06-01

    carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr-1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m-2 with 90% uncertainty bounds of (+0.08, +1.27) W m-2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m-2 with 90% uncertainty bounds of +0.17 to +2.1 W m-2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm

  11. Contribution of Black Carbon, Brown Carbon and Lensing Effect to Total Aerosol Absorption in Indo-Gangetic Plain

    NASA Astrophysics Data System (ADS)

    Shamjad, Pm; Tripathi, Sachchida; Bergin, Mike; Vreeland, Heidi

    2016-04-01

    This study reports the optical and physical properties of atmospheric and denuded (heated at 300°C) aerosols from Indo-Gangetic Plain (IGP) during 20 December 2014 to 28 February 2015. A Single Particle Soot Photometer (SP2) and High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) were used to measure black carbon (BC) and organic carbon (OC) in real time respectively. During experiments large scale carbonaceous aerosol loading is observed in IGP. Multiple biomass burning events are observed with varying intensity and duration. Refractive index of brown carbon (BrC) is derived from filter extracts using Liquid Core Wave Capillary Cell (LWCC). Refractive index of BrC at 405 is 4 times higher in IGP when compared to studies conducted in USA. Through Mie modelling we identified the percentage contribution of black carbon, BrC and lensing effect to total aerosol absorption. On average 75% of absorption is from black carbon alone, while rest is contributed from volatile components. Within the volatile component contribution, at 405 nm BrC contributes around 20% and rest from lensing effect. But at 781 nm lensing contributed more than BrC. Overall results indicate the special characteristics on BrC aerosols in IGP and the importance of considering spectral absorption in global aerosol modelling studies.

  12. Comparative inhalation toxicity of multi-wall carbon nanotubes, graphene, graphite nanoplatelets and low surface carbon black

    PubMed Central

    2013-01-01

    Background Carbon nanotubes, graphene, graphite nanoplatelets and carbon black are seemingly chemically identical carbon-based nano-materials with broad technological applications. Carbon nanotubes and carbon black possess different inhalation toxicities, whereas little is known about graphene and graphite nanoplatelets. Methods In order to compare the inhalation toxicity of the mentioned carbon-based nanomaterials, male Wistar rats were exposed head-nose to atmospheres of the respective materials for 6 hours per day on 5 consecutive days. Target concentrations were 0.1, 0.5, or 2.5 mg/m3 for multi-wall carbon nanotubes and 0.5, 2.5, or 10 mg/m3 for graphene, graphite nanoplatelets and low-surface carbon black. Toxicity was determined after end of exposure and after three-week recovery using broncho-alveolar lavage fluid and microscopic examinations of the entire respiratory tract. Results No adverse effects were observed after inhalation exposure to 10 mg/m3 graphite nanoplatelets or relatively low specific surface area carbon black. Increases of lavage markers indicative for inflammatory processes started at exposure concentration of 0.5 mg/m3 for multi-wall carbon nanotubes and 10 mg/m3 for graphene. Consistent with the changes in lavage fluid, microgranulomas were observed at 2.5 mg/m3 multi-wall carbon nanotubes and 10 mg/m3 graphene. In order to evaluate volumetric loading of the lung as the key parameter driving the toxicity, deposited particle volume was calculated, taking into account different methods to determine the agglomerate density. However, the calculated volumetric load did not correlate to the toxicity, nor did the particle surface burden of the lung. Conclusions The inhalation toxicity of the investigated carbon-based materials is likely to be a complex interaction of several parameters. Until the properties which govern the toxicity are identified, testing by short-term inhalation is the best option to identify hazardous properties in

  13. Airborne Observations of the Spatial and Temporal Variability of Tropospheric Carbon Dioxide during the INTEX-B Campaign

    NASA Technical Reports Server (NTRS)

    Vay, Stephanie A.; Choi, Younghoon; Woo, Jung-Hun; Barrick, John D.; Sachse, Glen W.; Blake, Donald; Avery, Melody A.; Fuelberg, Henry; Nolf, Scott

    2006-01-01

    The Intercontinental Chemical Transport Experiment-North America (INTEX-NA) is an international field campaign envisioned to investigate the transport and transformation of gases and aerosols on transcontinental/intercontinental scales and assess their impact on air quality and climate. Phase B (INTEX-B) of the mission was conducted during a 10- week period from March 1 to May 15, 2006 and focused initially on pollution outflow from the Mexico City Metropolitan Area, later addressing the transport of pollution from Asia to North America during springtime meteorological conditions. During the deployment, fast-response (1-s resolution) CO2 measurements were recorded aboard the NASA DC-8 providing valuable regional-scale information on carbon sources and sinks over sparsely sampled areas of North America and adjacent ocean basins. When coupled with the enormously sophisticated chemistry payload on the DC-8, these measurements collectively afford extremely powerful multi-tracer constraints for carbon source/sink attribution. Preliminary examination of the two data sets from the INTEX-B campaign, acquired one month apart, reveals not only the influence of the CO2 seasonal cycle, but also the preponderance of human population and industrial activity in the northern hemisphere. In this presentation, a synergy of the ensemble of airborne and surface observations, bottomup emission inventories, as well as transport history are invoked in a GIS framework to elucidate the source/sink processes reflected in the observations. The airborne CO2 data, along with simultaneous surface measurements (e.g. NOAA ESRL), are examined to establish the vertical distribution and variability of CO2 as a function of location. The role of localized sources, long-range transport, the biosphere, stratospheric exchange, and dynamical processes on the CO2 spatial variability observed throughout the tropospheric column will be discussed.

  14. Black Carbon Flux Across the Himalaya through the Kali Gandaki Valley in Nepal

    NASA Astrophysics Data System (ADS)

    Dhungel, S.; Panday, A. K.; Mahata, K. S.

    2013-12-01

    Significant increases in black carbon concentration have been observed in the recent years over the Indo-Gangetic plain, the foothills of the Himalaya, as well as the high Himalaya and the Tibetan Plateau. The concentration of increased black carbon can be significantly correlated to the albedo effect and the warming of atmosphere at high altitudes due to the deposition of black carbon in the snow clad mountains. It is hypothesized that this deposition contributes to increased melting of Himalayan glaciers and snowfields. Satellite images show increasing amounts of aerosol haze over the Indo-Gangetic plains which penetrate into the Himalayan valleys. But how does it reach the high altitude of the Himalayan cryosphere? To date, mechanisms of transport upwind of the valley from the Indo-Gangetic plains up to the Himalaya have not been thoroughly investigated. We hypothesize that wind systems in the deep river valleys that cut across the Himalaya, such as the Arun valley and Kali Gandaki valley, serve as important pathways for pollutant transport. In 2010 the University of Virginia, in collaboration with ICIMOD and Nepal Wireless, established an atmospheric research station in Jomsom, Nepal (28.78N, 83.42E, 2900 m.a.s.l.). The station is equipped to measure black carbon (BC), carbon monoxide (CO), and ozone concentrations. It also has an automated weather station, a filter sampler, and a NASA Aeronet Sunphotometer. Here we use our observations in Jomsom to present an estimate of the annual flux of black carbon from the Indo-Gangetic plains to the Tibetan Plateau through the Kali Gandaki valley. In this way, we gain insight into the significance of deep valleys and their role as pathways for pollutant transport.

  15. Black carbon and carbon monoxide over Bay of Bengal during W_ICARB: Source characteristics

    NASA Astrophysics Data System (ADS)

    Girach, I. A.; Nair, Vijayakumar S.; Babu, S. Suresh; Nair, Prabha R.

    2014-09-01

    The ship borne measurements of near-surface black carbon (BC) and carbon monoxide (CO) were carried out over Bay of Bengal (BoB) during the winter period of 2009 under W_ICARB, the second phase of ‘Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB)'. The CO mixing ratio and BC mass concentration varied in the ranges of 80-480 ppbv and 75-10,000 ng m-3, respectively over this marine region. The BC and CO showed similar variations over northern BoB where airmass from Indo-Gangetic Plain (IGP) region prevailed during the observations period leading to a very strong positive correlation. The association of BC and CO was poor over the eastern and southern part of BoB could be due to the removal of BC aerosols by rain and/or processes of dilution and mixing while transported over to BoB. The highest value of CO observed over eastern BoB was partially due to biomass burning over East Asia. The BC/CO ratio for IGP airmass found to be 20.3 ng m-3 ppb-1 and ∼16 ng m-3 ppb-1 during winter and pre-monsoon, respectively which indicate the role of biomass burning as the source of BC over the region. Based on the emission flux of CO from various inventories and observed BC/CO ratios during pre-monsoon and winter, the BC emission for India is estimated to be in the range of 0.78-1.23 Tg year-1. The analysis of scavenging of BC revealed the loss rate of BC due to relative humidity 0.39 ± 0.08 ng m-3 ppb-1 RH (%)-1 over northern BoB and 0.53 ± 0.04 ng m-3 ppb-1 RH (%)-1 over the southern-BoB during winter.

  16. A black body absorber from vertically aligned single-walled carbon nanotubes

    PubMed Central

    Mizuno, Kohei; Ishii, Juntaro; Kishida, Hideo; Hayamizu, Yuhei; Yasuda, Satoshi; Futaba, Don N.; Yumura, Motoo; Hata, Kenji

    2009-01-01

    Among all known materials, we found that a forest of vertically aligned single-walled carbon nanotubes behaves most similarly to a black body, a theoretical material that absorbs all incident light. A requirement for an object to behave as a black body is to perfectly absorb light of all wavelengths. This important feature has not been observed for real materials because materials intrinsically have specific absorption bands because of their structure and composition. We found a material that can absorb light almost perfectly across a very wide spectral range (0.2–200 μm). We attribute this black body behavior to stem from the sparseness and imperfect alignment of the vertical single-walled carbon nanotubes. PMID:19339498

  17. Nanoscale Interactions between Engineered Nanomaterials and Black Carbon (Biochar) in Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An understanding of the interactions between engineered nanomaterials (NMs) and soil constituents, and a comprehension of how these interactions may affect biological uptake and toxicity are currently lacking. Charcoal black carbon is a normal constituent of soils due to fire history, and can be pre...

  18. On-road black carbon instrument intercomparison and aerosol characteristics by driving environment

    EPA Science Inventory

    Large spatial variations of black carbon (BC) concentrations in the on-road and near-road environments necessitate measurements with high spatial resolution to assess exposure accurately. A series of measurements was made comparing the performance of several different BC instrume...

  19. MEASUREMENTS OF BLACK CARBON IN CHICAGO: IMPLICATIONS FOR CONTROLS ON DIESEL EMISSIONS

    EPA Science Inventory

    Black carbon measurements were made in Chicago from the roof of the Hinds Laboratory at the University of Chicago, in the southern part of the city. The BC content of fine aerosols was measured by using a seven-channel aethalometer with a sample inlet designed to admit aerosol...

  20. CARBON BLACK DISPERSION PRE-PLATING TECHNOLOGY FOR PRINTED WIRE BOARD MANUFACTURING

    EPA Science Inventory

    This evaluation addresses the product quality, waste reduction, and economic issues involved in replacing electroless copper with a carbon black dispersion technology. McCurdy Circuits of Orange County, California, currently has both processes in operation. McCurdy has found that...

  1. PULMONARY TOXICOLOGY OF SYNTHETIC AIR POLLUTION PARTICLES CONTAINING METAL SULFATES COMPARED TO CARBON BLACK AND DIESEL

    EPA Science Inventory

    PULMONARY TOXICITY OF SYNTHETIC AIR POLLUTION PARTICLES CONTAINING METAL SULFATES COMPARED TO CARBON BLACK AND DIESEL.

    M Daniels, A Ranade* & MJ Selgrade & MI Gilmour.
    Experimental Toxicology Division, ORD/NHEERL, U.S. EPA, RTP, NC. * Particle Technology, College Par...

  2. MULTIYEAR REAL-TIME MONITORING OF PARTICLES, PAH, AND BLACK CARBON IN AN OCCUPIED HOUSE

    EPA Science Inventory

    Concentrations of ultrafine, fine, and coarse particles, particle-bound polycyclic aromatic hydrocarbons (PAH), and black carbon have been measured continuously (every 1 to 5 minutes) in an occupied townhouse for 2-3 years. Also, since the summer of 1999, temperature (outdoors...

  3. INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 4. CARBON BLACK INDUSTRY

    EPA Science Inventory

    The catalog of Industrial Process Profiles for Environmental Use was developed as an aid in defining the environmental impacts of industrial activity in the United States Entries for each industry are in consistent format and form separate chapters of the study. The carbon black ...

  4. Evaluating Renewable Cornstarch/biochar Fillers as Potential Substitutes for Carbon Black in SBR Composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The continually growing demand for fossil fuels coupled with the potential risk of relying on foreign sources for these fuels strengthens the need to find renewable substitutes for petroleum products. Carbon black is a petroleum product that dominates the rubber composite filler market. Agricultur...

  5. Integrated chemiresistor and work function microsensor array with carbon black/polymer composite materials

    SciTech Connect

    Domansky, K.; Zapf, V.S.; Grate, J.W.; Ricco, A.J.; Yelton, W.G.; Janata, J.

    1998-05-01

    An array of chemically-sensitive field-effect transistors (CHEMFETs) that measure both work function and bulk resistance changes in thin films was used to detect volatile organic compounds. Carbon black/organic polymer composite films were deposited onto the CHEMFETs using an automated microdispensing method.

  6. Utilization of low-ash biochar to partially replace carbon black in SBR composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A biochar made from woody waste feedstock with low ash content was blended with carbon black as filler for styrene-butadiene rubber. At 10% total filler concentration (w/w), composites made from 25 or 50% biochar showed improved tensile strength, elongation, and toughness compared to similar composi...

  7. Surface-oxidized carbon black as a catalyst for the water oxidation and alcohol oxidation reactions.

    PubMed

    Suryanto, Bryan H R; Zhao, Chuan

    2016-05-11

    Carbon black (CB) is popularly used as a catalyst support for metal/metal oxide nanoparticles due to its large surface area, excellent conductivity and stability. Herein, we show that surface oxidized CB itself, after acidic treatment and electrochemical oxidation, exhibits significant catalytic activity for the electrochemical oxidation of water and alcohols. PMID:27097802

  8. Evaluation of Methods for the Determination of Black Carbon Emissions from an Aircraft Gas Turbine Engine

    EPA Science Inventory

    The emissions from aircraft gas turbine engines consist of nanometer size black carbon (BC) particles plus gas-phase sulfur and organic compounds which undergo gas-to-particle conversion downstream of the engine as the plume cools and dilutes. In this study, four BC measurement ...

  9. 40 CFR 721.10080 - Carbon black, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl) substituted] phenyl-modified...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Carbon black, 4- phenyl-modified... Specific Chemical Substances § 721.10080 Carbon black, 4- phenyl-modified, hydrochlorides (generic). (a... generically as carbon black, 4- phenyl-modified, hydrochlorides (PMN P-06-8) is subject to reporting...

  10. 40 CFR 721.10080 - Carbon black, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl) substituted] phenyl-modified...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Carbon black, 4- phenyl-modified... Specific Chemical Substances § 721.10080 Carbon black, 4- phenyl-modified, hydrochlorides (generic). (a... generically as carbon black, 4- phenyl-modified, hydrochlorides (PMN P-06-8) is subject to reporting...

  11. 40 CFR 721.10080 - Carbon black, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl) substituted] phenyl-modified...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Carbon black, 4- phenyl-modified... Specific Chemical Substances § 721.10080 Carbon black, 4- phenyl-modified, hydrochlorides (generic). (a... generically as carbon black, 4- phenyl-modified, hydrochlorides (PMN P-06-8) is subject to reporting...

  12. 40 CFR 721.10080 - Carbon black, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl) substituted] phenyl-modified...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Carbon black, 4- phenyl-modified... Specific Chemical Substances § 721.10080 Carbon black, 4- phenyl-modified, hydrochlorides (generic). (a... generically as carbon black, 4- phenyl-modified, hydrochlorides (PMN P-06-8) is subject to reporting...

  13. 40 CFR 721.10080 - Carbon black, 4-[(17-substituted-3,6,9,12,15-pentaazaheptadec-1-yl) substituted] phenyl-modified...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Carbon black, 4- phenyl-modified... Specific Chemical Substances § 721.10080 Carbon black, 4- phenyl-modified, hydrochlorides (generic). (a... generically as carbon black, 4- phenyl-modified, hydrochlorides (PMN P-06-8) is subject to reporting...

  14. Development of an Airborne Triple-Pulse 2-Micron Integrated Path Differential Absorption Lidar (IPDA) for Simultaneous Airborne Column Measurements of Carbon Dioxide and Water Vapor in the Atmosphere

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Yu, Jirong; Antill, Charles W.; Remus, Ruben

    2016-01-01

    This presentation will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar being developed at NASA Langley Research Center with support from NASA ESTO Instrument Incubator Program. The development of this active optical remote sensing IPDA instrument is targeted for measuring both atmospheric carbon dioxide and water vapor in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver and detector upgrades, laser packaging and lidar integration. Future plan for IPDA lidar system for ground integration, testing and flight validation will also be presented.

  15. A comparison between physical properties of carbon black-polymer and carbon nanotubes-polymer composites

    NASA Astrophysics Data System (ADS)

    Adohi, B. J.-P.; Mdarhri, A.; Prunier, C.; Haidar, B.; Brosseau, C.

    2010-10-01

    Multiple-walled carbon nanotube (CNT)-and carbon black (CB)-polymer composites have been fabricated by mechanical mixing with different loadings, the polymeric matrix being identical between the two series of samples. The main focus of this work is to report measurements of physical properties of these mixtures in ambient conditions and to discuss the origin of similarities and differences among them according the kind of carbonaceous filler. The uniform dispersion of the carbonaceous phase in the dielectric matrix was probed by high-resolution transmission electron microscopy. The good dispersibility of the filler particle is also reflected in the much lower conduction threshold observed for CNT-containing samples than in the CB composites. This is likely due to the high aspect ratio of the CNTs. Mechanical properties show that the storage modulus of the two kinds of samples is close to the modulus value of the neat styrene-butadiene rubber (SBR), independent of filler content over a wide range of compositions (ϕ <0.1) encompassing the percolation threshold. Microwave measurements show that the real part of the effective permittivity exhibits a flat frequency response, with the exception of the sample containing 30 vol % CB for which an inverse-power law is observed revealing a behavior that has been seen for many random heterogeneous soft materials. No resonant dielectric absorption is evidenced within the frequency range explored and for the filler concentrations investigated. The results were also compared with analytical effective (mean-field) models. The symmetric Bruggeman model is in very good agreement with the microwave effective permittivity once account is taken of the depolarization factor which is close to the value found for a three-dimensional (3D) random dispersion of monodisperse spherical conductive inclusions within a dielectric matrix. By combining microwave frequency-domain spectroscopy with uniaxial tension, we obtain the effective

  16. Morphology and Optical Properties of Black-Carbon Particles Relevant to Engine Emissions

    NASA Astrophysics Data System (ADS)

    Michelsen, H. A.; Bambha, R.; Dansson, M. A.; Schrader, P. E.

    2013-12-01

    Black-carbon particles are believed to have a large influence on climate through direct radiative forcing, reduction of surface albedo of snow and ice in the cryosphere, and interaction with clouds. The optical properties and morphology of atmospheric particles containing black carbon are uncertain, and characterization of black carbon resulting from engines emissions is needed. Refractory black-carbon particles found in the atmosphere are often coated with unburned fuel, sulfuric acid, water, ash, and other combustion by-products and atmospheric constituents. Coatings can alter the optical and physical properties of the particles and therefore change their optical properties and cloud interactions. Details of particle morphology and coating state can also have important effects on the interpretation of optical diagnostics. A more complete understanding of how coatings affect extinction, absorption, and incandescence measurements is needed before these techniques can be applied reliably to a wide range of particles. We have investigated the effects of coatings on the optical and physical properties of combustion-generated black-carbon particles using a range of standard particle diagnostics, extinction, and time-resolved laser-induced incandescence (LII) measurements. Particles were generated in a co-flow diffusion flame, extracted, cooled, and coated with oleic acid. The diffusion flame produces highly dendritic soot aggregates with similar properties to those produced in diesel engines, diffusion flames, and most natural combustion processes. A thermodenuder was used to remove the coating. A scanning mobility particle sizer (SMPS) was used to monitor aggregate sizes; a centrifugal particle mass analyzer (CPMA) was used to measure coating mass fractions, and transmission electron microscopy (TEM) was used to characterize particle morphologies. The results demonstrate important differences in optical measurements between coated and uncoated particles.

  17. Hierarchical meso-macro structure porous carbon black as electrode materials in Li-air battery

    NASA Astrophysics Data System (ADS)

    Kang, Jun; Li, Oi Lun; Saito, Nagahiro

    2014-09-01

    A new class of hierarchical structure porous carbon black, carbon nanoballs (CNBs), was generated by solution plasma process (SPP) with benzene. The structural characterization revealed that CNBs have excellent meso-macro hierarchical pore structure, with an averaged diameter size of 14.5 nm and a total pore volume of 1.13 cm3 g-1. The CNBs are aggregated forming inter-connected pore channels in different directions on both the meso- and macrometer length scales. The discharge capacity of CNBs reached 3600 mAh g-1, which exceeded the capacity of Ketjen Black EC-600JD (a commercial carbon black with highest cell performance) by 30-40%. The excellent discharge capacity was contributed by the co-existence of high pore volume and meso-macro hierarchical porous structure. This new class carbon material exhibited higher discharge capacity compared to commercial porous carbon materials, and is possible to apply as the next generation of electrode materials in lithium-air (Li-air) battery. The structural and electrochemical properties accompanied with the synthesis mechanism of CNBs were discussed in details.

  18. Quantifying immediate radiative forcing by black carbon and organic matter with the Specific Forcing Pulse

    NASA Astrophysics Data System (ADS)

    Bond, T. C.; Zarzycki, C.; Flanner, M. G.; Koch, D. M.

    2010-06-01

    We propose a measure to quantify climate warming or cooling by pollutants with atmospheric lifetimes of less than one year: the Specific Forcing Pulse (SFP). SFP is the amount of energy added to the Earth system per mass of pollutant emitted. Global average SFP for black carbon, including atmosphere and cryosphere, is 1.12 GJ g-1 and that for organic matter is -0.061 GJ g-1. We provide regional values for black carbon (BC) and organic matter (OM) emitted from 23 source-region combinations, divided between atmosphere and cryosphere impacts and identifying forcing by latitude. Regional SFP varies by about 40% for black carbon. This variation is relatively small because of compensating effects; particles from regions that affect ice albedo typically have shorter atmospheric lifetimes because of lower convection. The ratio between BC and OM SFP implies that, for direct forcing, an OM:BC mass ratio of 15 has a neutral effect on top-of-atmosphere direct forcing for any region, and any lower ratio induces direct warming. However, important processes, particularly cloud changes that tend toward cooling, have not been included here. We demonstrate ensemble adjustment, in which we produce a "best estimate" by combining a suite of diverse but simple models and enhanced models of greater complexity. Adjustments for black carbon internal mixing and for regional variability are discussed; regions with convection are implicated in greater model diversity. SFP expresses scientific uncertainty and separates it from policy uncertainty; the latter is caused by disagreements about the relevant time horizon, impact, or spatial scale of interest. However, metrics used in policy discussions, such as global warming potentials, are easily derived from SFP. Global-average SFP for biofuel and fossil fuel emissions translates to a 100-year GWP of about 760 for black carbon and -40 for organic matter when snow forcing is included. Ensemble-adjusted estimates of atmospheric radiative impact by

  19. Joseph Black, carbon dioxide, latent heat, and the beginnings of the discovery of the respiratory gases.

    PubMed

    West, John B

    2014-06-15

    The discovery of carbon dioxide by Joseph Black (1728-1799) marked a new era of research on the respiratory gases. His initial interest was in alkalis such as limewater that were thought to be useful in the treatment of renal stone. When he studied magnesium carbonate, he found that when this was heated or exposed to acid, a gas was evolved that he called "fixed air" because it had been combined with a solid material. He showed that the new gas extinguished a flame, that it could not support life, and that it was present in gas exhaled from the lung. Within a few years of his discovery, hydrogen, nitrogen, and oxygen were also isolated. Thus arguably Black's work started the avalanche of research on the respiratory gases carried out by Priestley, Scheele, Lavoisier, and Cavendish. Black then turned his attention to heat and he was the first person to describe latent heat, that is the heat added or lost when a liquid changes its state, for example when water changes to ice or steam. Latent heat is a key concept in thermal physiology because of the heat lost when sweat evaporates. Black was a friend of the young James Watt (1736-1819) who was responsible for the development of early steam engines. Watt was puzzled why so much cooling was necessary to condense steam into water, and Black realized that the answer was the latent heat. The resulting improvements in steam engines ushered in the Industrial Revolution. PMID:24682452

  20. First Airborne IPDA Lidar Measurements of Methane and Carbon Dioxide Applying the DLR Greenhouse Gas Sounder CHARM-F

    NASA Astrophysics Data System (ADS)

    Amediek, A.; Ehret, G.; Fix, A.; Wirth, M.; Quatrevalet, M.; Büdenbender, C.; Kiemle, C.; Loehring, J.; Gerbig, C.

    2015-12-01

    First airborne measurement using CHARM-F, the four-wavelengths lidar for simultaneous soundings of atmospheric CO2 and CH4, were performed in Spring 2015 onboard the German research aircraft HALO. The lidar is designed in the IPDA (integrated path differential absorption) configuration using short double pulses, which gives column averaged gas mixing ratios between aircraft and ground. HALO's maximum flight altitude of 15 km and special features of the lidar, such as a relatively large laser ground spot, enable the CHARM-F system to be an airborne demonstrator for future spaceborne greenhouse gas lidars. Due to a high technological conformity this applies in particular to the French-German satellite mission MERLIN, the spaceborne methane IPDA lidar. The successfully completed flight measurements provide a valuable dataset, which supports the retrieval algorithm development for MERLIN notably. The flights covered different ground cover types, different orography types as well as the sea. Additionally, we captured different cloud conditions, at which the broken cloud case is a matter of particular interest. This dataset allows detailed analyses of measurement sensitivities, general studies on the IPDA principle and on technical details of the system. These activities are supported by another instrument onboard: a cavity ring down spectrometer, providing in-situ data of carbon dioxide, methane and water vapor with high accuracy and precision, which is ideal for validation purposes of the lidar. Additionally the onboard instrumentation of HALO gives information about pressure and temperature for cross-checking the ECMWF data, which are intended to be used for calculating the weighting function, the key quantity for the retrieval of gas column mixing ratios from the measured gas optical depths. In combination with dedicated descents into the boundary layer and subsequent ascents, a self-contained dataset for characterizations of CHARM-F is available.

  1. Development and Preliminary Tests of an Open-Path Airborne Diode Laser Absorption Instrument for Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Diskin, G. S.; DiGangi, J. P.; Yang, M. M.; Rana, M.; Slate, T. A.

    2015-12-01

    Carbon dioxide (CO2) is well known for its importance as an atmospheric greenhouse gas, with many sources and sinks around the globe. Understanding the fluxes of carbon into and out of the atmosphere is a complex and daunting challenge. One tool applied by scientists to measure the vertical flux of CO2 near the surface uses the eddy covariance technique, most often from towers but also from aircraft flying specific patterns over the study area. In this technique, variations of constituents of interest are correlated with fluctuations in the local vertical wind velocity. Measurement requirements are stringent, particularly with regard to precision, sensitivity to small changes, and temporal sampling rate. In addition, many aircraft have limited payload capability, so instrument size, weight, and power consumption are also important considerations. We report on the development and preliminary application of an airborne sensor for the measurement of atmospheric CO2. The instrument, modeled on the successful DLH (Diode Laser Hygrometer) series of instruments, has been tested in the laboratory and on the NASA DC-8 aircraft. Performance parameters such as accuracy, precision, sensitivity, specificity, and temporal response are discussed in the context of typical atmospheric variability and suitability for flux measurement applications. On-aircraft, in-flight intercomparison data have been obtained and will be discussed as well. Performance of the instrument has been promising, and continued flight testing is planned during 2016.

  2. Development and Preliminary Tests of an Open-Path Airborne Diode Laser Absorption Instrument for Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Diskin, Glenn S.; DiGangi, Joshua P.; Yang, Melissa; Slate, Thomas A.; Rana, Mario

    2015-01-01

    Carbon dioxide (CO2) is well known for its importance as an atmospheric greenhouse gas, with many sources and sinks around the globe. Understanding the fluxes of carbon into and out of the atmosphere is a complex and daunting challenge. One tool applied by scientists to measure the vertical flux of CO2 near the surface uses the eddy covariance technique, most often from towers but also from aircraft flying specific patterns over the study area. In this technique, variations of constituents of interest are correlated with fluctuations in the local vertical wind velocity. Measurement requirements are stringent, particularly with regard to precision, sensitivity to small changes, and temporal sampling rate. In addition, many aircraft have limited payload capability, so instrument size, weight, and power consumption are also important considerations. We report on the development and preliminary application of an airborne sensor for the measurement of atmospheric CO2. The instrument, modeled on the successful DLH (Diode Laser Hygrometer) series of instruments, has been tested in the laboratory and on the NASA DC-8 aircraft. Performance parameters such as accuracy, precision, sensitivity, specificity, and temporal response are discussed in the context of typical atmospheric variability and suitability for flux measurement applications. On-aircraft, in-flight data have been obtained and are discussed as well. Performance of the instrument has been promising, and continued flight testing is planned during 2016.

  3. Determining Sorption Properties of Pyrogenic Black Carbon for Some Heavy Metals

    NASA Astrophysics Data System (ADS)

    Nicholls, P.; Cadol, D. D.; Galanter, A.

    2014-12-01

    There have been two major fires in the Valles Caldera, located in the Jemez Mountains of Northern New Mexico, within the last three years: the Thompson Ridge fire (June 2013) and the Las Conchas fire (July 2011). During forest fires, contaminants are released from the incomplete combustion of organic matter, from mineral assemblages of the natural soil, and from pre-existing contaminants that have accumulated in biomass and soils. The transport and sequestration of these contaminants is an important factor in determining environmental soil and water quality following fires. Soils containing black carbon (BC) have high sorption capacities for certain contaminants due to its high surface area and cation exchange capacity. The purpose of this project is to quantify the sorption properties of pyrogenic black carbon (PyC), or black carbon formed after the incomplete combustion of organic carbon during forest fires, and soils found in recently burned areas of Northern NM and to determine the environmental impact of soils containing PyC. We used batch equilibrium experiments to determine the sorption properties of BC for selected metals (chromium, lead, and arsenic). Samples tested include naturally occurring soils, concentrated PyC, mixtures of soil and PyC, industrial BC, and a control with low carbon and sorption. Contaminant concentrations were also measured from the soils sampled in the field site. Preliminary results suggest that industrial BC has the highest sorption capacity for heavy metals and the quickest time to equilibrium. As PyC concentrations in the soil increase, sorption capacity is expected to increase. With complete results, the environmental significance of black carbon in the soil, including how PyC affects the transport of solutes in soils, will be evaluated.

  4. Buried black soils surrounding the white roof of Africa as regional carbon storage hotspot

    NASA Astrophysics Data System (ADS)

    Zech, M.; Hörold, C.; Leiber-Sauheitl, K.; Hemp, A.; Zech, W.

    2012-04-01

    Mt. Kilimanjaro, the at least still "white roof" of Africa, attracts much attention because of its dramatically shrinking ice caps. By contrast, it was discovered only recently that intriguing paleosol sequences with buried and often strikingly black soils developed along the slopes of Mt. Kilimanjaro during the Late Quaternary. In our study we investigated in detail the soil organic carbon (SOC) contents and SOC stocks of soil profiles which are situated along two altitudinal transects; one along the humid southern slopes and the other one along the more arid northern slopes. We found up to 3 m thick paleosol sequences occurring almost area-wide particularly in the montane forest zone. SOC contents are remarkable high with values of up to more than 10%, indicating high preservation of soil organic matter (SOM). We suggest that the SOM preservation is favoured by several factors, such as (i) the burial by aeolian deposition, (ii) lower temperatures and (iii) more resistant Erica litter during glacial periods, (iv) formation of stable organo-mineral complexes and (v) high black carbon (BC) contents. The SOC-rich buried black soils account for mean SOC stocks of ~82 kg m-2 in the montane rainforest. Extrapolating this SOC storage and comparing it with the SOC storage achieved by the surrounding savannah soils of the Maasai Steppe highlights that the buried black soils are a prominent regional carbon storage hotspot.

  5. Estimating Carbon STOCK Changes of Mangrove Forests Using Satellite Imagery and Airborne LiDAR Data in the South Sumatra State, Indonesia

    NASA Astrophysics Data System (ADS)

    Maeda, Y.; Fukushima, A.; Imai, Y.; Tanahashi, Y.; Nakama, E.; Ohta, S.; Kawazoe, K.; Akune, N.

    2016-06-01

    The purposes of this study were 1) to estimate the biomass in the mangrove forests using satellite imagery and airborne LiDAR data, and 2) to estimate the amount of carbon stock changes using biomass estimated. The study area is located in the coastal area of the South Sumatra state, Indonesia. This area is approximately 66,500 ha with mostly flat land features. In this study, the following procedures were carried out: (1) Classification of types of tree species using Satellite imagery in the study area, (2) Development of correlation equations between spatial volume based on LiDAR data and biomass stock based on field survey for each types of tree species, and estimation of total biomass stock and carbon stock using the equation, and (3) Estimation of carbon stock change using Chronological Satellite Imageries. The result showed the biomass and the amount of carbon stock changes can be estimated with high accuracy, by combining the spatial volume based on airborne LiDAR data with the tree species classification based on satellite imagery. Quantitative biomass monitoring is in demand for projects related to REDD+ in developing countries, and this study showed that combining airborne LiDAR data with satellite imagery is one of the effective methods of monitoring for REDD+ projects.

  6. Hydrogen production using thermocatalytic decomposition of methane on Ni30/activated carbon and Ni30/carbon black.

    PubMed

    Srilatha, K; Viditha, V; Srinivasulu, D; Ramakrishna, S U B; Himabindu, V

    2016-05-01

    Hydrogen is an energy carrier of the future need. It could be produced from different sources and used for power generation or as a transport fuel which mainly in association with fuel cells. The primary challenge for hydrogen production is reducing the cost of production technologies to make the resulting hydrogen cost competitive with conventional fuels. Thermocatalytic decomposition (TCD) of methane is one of the most advantageous processes, which will meet the future demand, hence an attractive route for COx free environment. The present study deals with the production of hydrogen with 30 wt% of Ni impregnated in commercially available activated carbon and carbon black catalysts (samples coded as Ni30/AC and Ni30/CB, respectively). These combined catalysts were not attempted by previous studies. Pure form of hydrogen is produced at 850 °C and volume hourly space velocity (VHSV) of 1.62 L/h g on the activity of both the catalysts. The analysis (X-ray diffraction (XRD)) of the catalysts reveals moderately crystalline peaks of Ni, which might be responsible for the increase in catalytic life along with formation of carbon fibers. The activity of carbon black is sustainable for a longer time compared to that of activated carbon which has been confirmed by life time studies (850 °C and 54 sccm of methane). PMID:26233751

  7. Assessing mining impacts from dust and black carbon on Arctic snow in Svalbard, Norway

    NASA Astrophysics Data System (ADS)

    Khan, A. L.; Dierssen, H. M.; Schwarz, J. P.; Ding, Y.; Jaffe, R.; Painter, T. H.; McKnight, D. M.; Hermanson, M. H.

    2014-12-01

    Coal mining in Svalbard has been ongoing since the early 1900's. In this study, spectral reflectance of undisturbed seasonal surface snow near an active coal mine closest to the largest settlement of Longyearbyen (78.2° N) with refractory black carbon (rBC) up to 345 ppb are compared to a non-contaminated pristine site at Woodfjorden (79.5 ° N) near the northern end of Svalbard with rBC ~1 ppb. Dissolved black carbon (DBC) measurements are also assessed as carbon passing through a 0.7 um filter and vary from 1 to 75 ppb. Reflectance spectra decreased dramatically across all wavelengths up to 1400 nm with increasing black carbon and the reflectance spectra did not converge at infrared wavelengths. At the most contaminated site with rBC of 345 ppb and DBC of 75 ppb, absolute reflectance was much lower than previously published results with values between 10 and 20% in blue wavelengths. This indicates the potential impact of BC on natural long-term contaminated snow spectra subject to melt and refreezing and the possibility to serve as a natural end member for global remote sensing studies. These results are also significant because there is increasing pressure being put on Arctic communities to increase mining exploration. Additionally, diminishing sea-ice resulting in increased shipping traffic will also contribute to BC impacts in the Arctic.

  8. IMPROVED PREDICTION OF THE VERTICAL PROFILE OF ATMOSPHERIC BLACK CARBON: DEVELOPMENT AND EVALUATION OF WRF-CMAQ

    EPA Science Inventory

    Advanced model descriptions of cloud processing of atmospheric pollutants will improve predicted vertical profiles of optically active particulate carbon (e.g., black carbon (Be) and other short lived climate forcers (SLCFs) such as "brown" carbon). More accurate prediction of...

  9. Impact of cement renders on airborne ozone and carbon dioxide concentrations

    NASA Astrophysics Data System (ADS)

    Taylor-Lange, Sarah C.; Juenger, Maria C. G.; Siegel, Jeffrey A.

    2013-05-01

    The uptake of pollutants by building surfaces can potentially improve both indoor and outdoor air quality. Cement renders provide a unique opportunity for passive pollutant removal because they can cover large surface areas. This study investigated the passive removal of carbon dioxide and ozone by cement renders having varied binder compositions and curing durations. The results from this study demonstrated shorter curing durations resulted in greater pollutant uptake. However, the use of the supplementary cementitious material, metakaolin, in the cement render increased the carbon dioxide ingress while decreasing the ozone uptake. Therefore, the adaptation of the render composition for the best effective application may result in valuable indoor air quality or carbon savings consequences.

  10. Isotopically Light Organic Carbon in Phanerozoic Black Shales: Diagenetic, Source, or Environmental Signal?

    NASA Astrophysics Data System (ADS)

    Meyers, P. A.

    2011-12-01

    A curious depletion of 13C in the organic matter of marine black shales has been widely recognized ever since the advent of carbon isotope measurements half a century ago. Paleozoic and Mesozoic black shales commonly have del13C values between -29 and -26 permil, whereas modern marine organic matter has values between -22 and -18 permil. The black shale values mimic those of continental organic matter, yet sedimentary settings and Rock-Eval results indicate that the organic matter is marine in origin. This presentation will overview and discuss hypotheses to explain the isotopically light values of the black shales. First, the preferential removal of isotopically heavier organic matter components such as carbohydrates by diagenesis will be examined and shown to be wanting. Second, the possible oxidation of isotopically light methane released from clathrates that would have altered the DIC pool available to phytoplankton will be considered and also be found unlikely. A third possibility - that greater concentrations of CO2 in the greenhouse atmospheres that corresponded with deposition of many black shales allowed greater discrimination against 13C during photosynthesis - will be evaluated from del13C values of bulk carbon and of algal and land-plant biomarker molecules. Finally, the possibility that stronger stratification of the surface ocean may have magnified photic zone recycling of organic matter and reincorporation of its isotopically light carbon into fresh biomass will be considered. Although the fourth possibility is contrary to the conditions of vertical mixing of nutrients that exist in modern upwelling systems and that are responsible for their high productivity, it is consistent with the strongly stratified conditions that accompanied the high productivity that produced the Pliocene-Pleistocene sapropels of the Mediterranean Sea. Because the sapropels and most Phanerozic black shales share del15N values near 0 permil, nitrogen fixation evidently was

  11. Net removal of dissolved organic carbon in the subsurface Black Sea

    NASA Astrophysics Data System (ADS)

    Margolin, A. R.; Gerringa, L. J.; Hansell, D. A.; Rijkenberg, M. J. A.

    2015-12-01

    Dissolved organic carbon (DOC) concentrations in the deep Black Sea are ~2.5 times higher than found in the global ocean. The two major external sources of DOC are rivers and the Mediterranean, while expansive phytoplankton blooms contribute autochthonous carbon to the Black Sea's ~800 Tg C DOC reservoir. Here, a basin-wide zonal section of DOC is explored using data from the 2013 Dutch GEOTRACES GA04-N "MedBlack" cruise 64PE373. DOC distributions are interpreted with respect to well-described hydrographic and biogeochemical layers of the Black Sea. DOC concentrations were >180 µmol kg-1 at the surface, decreasing to ~125 µmol kg-1 at the base of the oxic layer and reaching a minimum of ~113 µmol kg-1 in the upper anoxic layer between ~150 and 500 m. Maximum anoxic layer concentrations of 122 µmol kg-1 were found in the homogeneous benthic bottom layer (>1775 m). Determined from the relationship of DOC with salinity, we found that ~34-41 µmol kg-1 was removed from the basin's oxic layer in <5 years, and an additional 13 ± 5 µmol kg-1 was removed from the anoxic layer during its ~300-600 years residence time, given steady state. We find no evidence for DOC accumulation in the anoxic Black Sea, and suggest that concentrations are elevated relative to the ocean due to input of terrigenous DOC from rivers. The Black Sea's relatively elevated DOC pool may be analogous to the previously hypothesized anoxic Eocene ocean's elevated reservoir if the Eocene ocean received a substantial amount of terrigenous DOC from rivers.

  12. Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide

    NASA Astrophysics Data System (ADS)

    Frankenberg, Christian; Kulawik, Susan S.; Wofsy, Steven C.; Chevallier, Frédéric; Daube, Bruce; Kort, Eric A.; O'Dell, Christopher; Olsen, Edward T.; Osterman, Gregory

    2016-06-01

    In recent years, space-borne observations of atmospheric carbon dioxide (CO2) have been increasingly used in global carbon-cycle studies. In order to obtain added value from space-borne measurements, they have to suffice stringent accuracy and precision requirements, with the latter being less crucial as it can be reduced by just enhanced sample size. Validation of CO2 column-averaged dry air mole fractions (XCO2) heavily relies on measurements of the Total Carbon Column Observing Network (TCCON). Owing to the sparseness of the network and the requirements imposed on space-based measurements, independent additional validation is highly valuable. Here, we use observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) flights from 01/2009 through 09/2011 to validate CO2 measurements from satellites (Greenhouse Gases Observing Satellite - GOSAT, Thermal Emission Sounder - TES, Atmospheric Infrared Sounder - AIRS) and atmospheric inversion models (CarbonTracker CT2013B, Monitoring Atmospheric Composition and Climate (MACC) v13r1). We find that the atmospheric models capture the XCO2 variability observed in HIPPO flights very well, with correlation coefficients (r2) of 0.93 and 0.95 for CT2013B and MACC, respectively. Some larger discrepancies can be observed in profile comparisons at higher latitudes, in particular at 300 hPa during the peaks of either carbon uptake or release. These deviations can be up to 4 ppm and hint at misrepresentation of vertical transport. Comparisons with the GOSAT satellite are of comparable quality, with an r2 of 0.85, a mean bias μ of -0.06 ppm, and a standard deviation σ of 0.45 ppm. TES exhibits an r2 of 0.75, μ of 0.34 ppm, and σ of 1.13 ppm. For AIRS, we find an r2 of 0.37, μ of 1.11 ppm, and σ of 1.46 ppm, with latitude-dependent biases. For these comparisons at least 6, 20, and 50 atmospheric soundings have been averaged for GOSAT, TES, and AIRS

  13. The structure of carbon black-elastomer composites by small-angle neutron scattering and the method of contrast variation

    SciTech Connect

    Hjelm, R.P.; Wampler, W.; Gerspacher, M.

    1996-07-01

    We have been exploring the use of small-angle neutron scattering and the method of contrast variation to give a new look at a very old problem: reinforcement of elastomers by carbon black in durable rubber products. Carbon black has a hierarchy of structures consisting of particles covalently bound into aggregates, which in turn associate by weak interactions into agglomerates. We found that in one carbon black, HSA, the aggregates are rodlike, containing an average of 4-6 particles. The aggregates have an outer graphitic shell and an inner core of lower density carbon. The core is continuous throughout the carbon black aggregate. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene and that the agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 10 {angstrom}. Further studies using production carbon blacks suggest that these structural characteristics are generally present in commercial rubber composites.

  14. Effect of pyrolyzed carbon black on asphalt cement. Part 2. Asphalt binder. Final report, September 1993-May 1995

    SciTech Connect

    Zeng, Y.; Lovell, C.W.

    1996-02-20

    Scrap tires derived from automobiles have become a large environmental problem in the United States. In the study, research is carried out to investigate the potential use of tire-derived pyrolyzed carbon black from scrap tires as an asphalt cement modifier. The asphlat cements used in the research were AC10 and AC20. Penetration and softening point tests were performed to obtain the consistency of the asphalt cements. The pyrolyzed carbon black, as provided by Wolf Industries, was combined with the asphalt cement in the following percentages: 5%, 10%, 15% and 20%. Penetration, softening point and ductility tests were performed to determine the temperature susceptibility of the modified binder as altered by the pyrolyzed carbon black. In order that the results are comparable to previous testing, commercial carbon black purchased from CABOT Industry was also used as a modifier in the tests. The same test procedures were applied to the asphalt cements modified by commercial carbon black. The test results contained in the report illustrate the viability of the pyrolyzed carbon black as an asphalt modifier. Recommendations are provided to facilitate further research on this particular project. A preliminary assessment of a test road using the pyrolyzed carbon is appended.

  15. Damage development during low cycle fatigue of carbon-black loaded SBR. [Styrene butadiene rubber containing 0, 15, 25, and 35 wt % carbon black

    SciTech Connect

    Lesuer, D.; Goldberg, A.; Hiromoto, D.; Patt, J.

    1984-06-18

    Fatigue of elastomers is a subject that has received considerable study over the years. This paper explores the problem of damage accumulation in a series of styrene butadiene rubber (SBR) based compounds containing 0, 15, 25, and 35 wt % carbon-black under conditions in which a limited number of higher stress cycles have been applied to the material (referred to here as low cycle fatigue). Damage development in elastomers can take many forms. Generally speaking, one can classify the degradation as mechanical or chemical in origin. The most obvious form of mechanical damage is flaw or cut growth, while typical examples of chemical damage include chain scission or thermal oxidation. The fatigue crack growth relationship given in Equation 1 obviously only applies to flaw growth. However, it does an excellent job of following the data and exhibits the threshold behavior observed in both SBR and SBR-35 at room temperature. At higher temperatures, the damaged material shows an increasing deviation from threshold behavior. The obvious implication is that some thermally activated damage mechanism is degrading the material. In previous work, carbon-black loaded SBR subjected to a high temperature, high stress environment was shown to undergo a thermal-mechanical oxidation process. Certainly, this process is a candidate for a damage mechanism in these studies. 6 references, 14 figures, 1 table.

  16. Modeling coal liquefaction: Decomposition of 4-(1-naphthylmethyl)bibenzyl catalyzed by carbon black

    SciTech Connect

    Farcasiu, M.; Smith, C. )

    1990-01-01

    The early stages of coal liquefaction involve cleavage of methylene and ethylene bridges connecting aromatic rings. The authors modeled this process by the reaction of 4-(1-naphthylmethyl)bibenzyl (I) in the presence of a hydrogen donor (9,10-dihydrophenanthrene). The reactions were conducted over a range of temperatures (320-430{degree}C) and reaction times (30-90 min). They found that the bond between the methylene group and the naphthalene ring and the methylene to methylene bond of bibenzyl moiety are broken with equal probability. Addition of carbon black (BP 2000) as catalyst (2-10%) increases significantly the conversion of I. This particular carbon black is, a very active and selective catalyst for the cleavage of the naphthyl-to-methylene bond.

  17. Voltammetric studies of the behavior of carbon black during phenol oxidation on Ti/Pt electrodes

    SciTech Connect

    Boudenne, J.L.; Cerclier, O.; Bianco, P.

    1998-08-01

    Oxidation of phenol on platinum electrodes rapidly leads to the formation of a passivating film on the surface of these electrodes. Studies of cyclic voltammetry and chronoamperometry combined with high-performance liquid chromatography (HPLC) analyses have shown that the presence of carbon black avoids these phenomena of passivation and thus allows the complete mineralization of phenol. The nature of carbon black and the pH value are two important factors which are studied here. VULCAN XC-72 R, an intrinsic p-type semiconductor, having a large specific area, showed all its efficiency when cyclic voltammetry experiments were carried out in an acid medium (pH 2.2). HPLC analyses revealed the appearance of several by-products such as hydroquinone and benzoquinone, and maleic and fumaric acids.

  18. [Observational study of black carbon aerosol during straw-burning period].

    PubMed

    Wu, De-xia; Wei, Qing-nong; Wei, Jian-li; Liu, Shi-sheng; Feng, Wei-wei

    2008-12-01

    Black carbon aerosol (BC) has been measured at three sites in Hefei City during May and June, 2007. Analyzing these real-time BC data, the concentration characters and the sources of black carbon aerosol can be found. The average concentrations of BC in normal period and straw-burning period are 4.85 microg/m3 and 8.38 microg/m3, respectively. The significant difference shows that the straw-burning is one of the main sources. The correlation coefficients between daily average concentration of BC and PM10 is 0.74, while the values of BC/PM10 in normal period and straw-burning period are 4.7% and 7.9%, respectively. Through comparing to the BC concentration during straw-burning period in 2004, the results indicated that pollution of BC has reduced after straw-burning was forbidden by the government. PMID:19256359

  19. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black.

    PubMed

    Vuong, Ngoc Q; Goegan, Patrick; Mohottalage, Susantha; Breznan, Dalibor; Ariganello, Marianne; Williams, Andrew; Elisma, Fred; Karthikeyan, Subramanian; Vincent, Renaud; Kumarathasan, Premkumari

    2016-09-01

    Here, we have described the dataset relevant to the A549 cellular proteome changes after exposure to either titanium dioxide or carbon black particles as compared to the non-exposed controls, "Proteomic changes in human lung epithelial cells (A549) in response to carbon black and titanium dioxide exposures" (Vuong et al., 2016) [1]. Detailed methodologies on the separation of cellular proteins by 2D-GE and the subsequent mass spectrometry analyses using MALDI-TOF-TOF-MS are documented. Particle exposure-specific protein expression changes were measured via 2D-GE spot volume analysis. Protein identification was done by querying mass spectrometry data against SwissProt and RefSeq protein databases using Mascot search engine. Two-way ANOVA analysis data provided information on statistically significant A549 protein expression changes associated with particle exposures. PMID:27508218

  20. Tracking airborne CO2 mitigation and low cost transformation into valuable carbon nanotubes.

    PubMed

    Ren, Jiawen; Licht, Stuart

    2016-01-01

    Primary evidence of the direct uptake of atmospheric CO2 and direct transformation into carbon nanotubes, CNTs, is demonstrated through isotopic labeling, and provides a new high yield route to mitigate this greenhouse gas. CO2 is converted directly to CNTs and does not require pre-concentration of the airbone CO2. This C2CNT (CO2 to carbon nanotube) synthesis transforms CO2-gas dissolved in a 750 °C molten Li2CO3, by electrolysis, into O2-gas at a nickel electrode, and at a steel cathode into CNTs or carbon or nanofibers, CNFs. CNTs are synthesized at a 100-fold price reduction compared to conventional chemical vapour deposition, CVD, synthesis. The low cost conversion to a stable, value-added commodity incentivizes CO2 removal to mitigate climate change. The synthesis allows morphology control at the liquid/solid interface that is not available through conventional CVD synthesis at the gas/solid interface. Natural abundance (12)CO2 forms hollow CNTs, while equivalent synthetic conditions with heavier (13)CO2 favours closed core CNFs, as characterized by Raman, SEM and TEM. Production ease is demonstrated by the first synthesis of a pure (13)C multiwalled carbon nanofiber. PMID:27279594

  1. Tracking airborne CO2 mitigation and low cost transformation into valuable carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ren, Jiawen; Licht, Stuart

    2016-06-01

    Primary evidence of the direct uptake of atmospheric CO2 and direct transformation into carbon nanotubes, CNTs, is demonstrated through isotopic labeling, and provides a new high yield route to mitigate this greenhouse gas. CO2 is converted directly to CNTs and does not require pre-concentration of the airbone CO2. This C2CNT (CO2 to carbon nanotube) synthesis transforms CO2-gas dissolved in a 750 °C molten Li2CO3, by electrolysis, into O2-gas at a nickel electrode, and at a steel cathode into CNTs or carbon or nanofibers, CNFs. CNTs are synthesized at a 100-fold price reduction compared to conventional chemical vapour deposition, CVD, synthesis. The low cost conversion to a stable, value-added commodity incentivizes CO2 removal to mitigate climate change. The synthesis allows morphology control at the liquid/solid interface that is not available through conventional CVD synthesis at the gas/solid interface. Natural abundance 12CO2 forms hollow CNTs, while equivalent synthetic conditions with heavier 13CO2 favours closed core CNFs, as characterized by Raman, SEM and TEM. Production ease is demonstrated by the first synthesis of a pure 13C multiwalled carbon nanofiber.

  2. Tracking airborne CO2 mitigation and low cost transformation into valuable carbon nanotubes

    PubMed Central

    Licht, Stuart

    2016-01-01

    Primary evidence of the direct uptake of atmospheric CO2 and direct transformation into carbon nanotubes, CNTs, is demonstrated through isotopic labeling, and provides a new high yield route to mitigate this greenhouse gas. CO2 is converted directly to CNTs and does not require pre-concentration of the airbone CO2. This C2CNT (CO2 to carbon nanotube) synthesis transforms CO2-gas dissolved in a 750 °C molten Li2CO3, by electrolysis, into O2-gas at a nickel electrode, and at a steel cathode into CNTs or carbon or nanofibers, CNFs. CNTs are synthesized at a 100-fold price reduction compared to conventional chemical vapour deposition, CVD, synthesis. The low cost conversion to a stable, value-added commodity incentivizes CO2 removal to mitigate climate change. The synthesis allows morphology control at the liquid/solid interface that is not available through conventional CVD synthesis at the gas/solid interface. Natural abundance 12CO2 forms hollow CNTs, while equivalent synthetic conditions with heavier 13CO2 favours closed core CNFs, as characterized by Raman, SEM and TEM. Production ease is demonstrated by the first synthesis of a pure 13C multiwalled carbon nanofiber. PMID:27279594

  3. Nitric Acid Uptake and Decomposition on Black Carbon (Soot) Surfaces: Its Implications for the Upper Troposphere and Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Choi, W.; Leu, M. T.

    1998-01-01

    Black carbon particles (soot) are formed as a result of incomplete combustion processes and are ubiquitous in the atmosphere. The lower troposphere contains plenty of soot particles whose principal sources are fossil fuel and biomass combustion at the ground level.

  4. Distribution of black carbon in Ponderosa pine litter and soils following the High Park wildfire

    NASA Astrophysics Data System (ADS)

    Boot, C. M.; Haddix, M.; Paustian, K.; Cotrufo, M. F.

    2014-12-01

    Black carbon (BC), the heterogeneous product of burned biomass, is a critical component in the global carbon cycle, yet timescales and mechanisms for incorporation into the soil profile are not well understood. The High Park Fire, which took place in northwestern Colorado in the summer of 2012, provided an opportunity to study the effects of both fire intenstiy and geomorphology on properties of carbon (C), nitrogen (N), and BC in the Cache La Poudre River drainage. We sampled montane Ponderosa pine litter, 0-5 cm soils, and 5-15 cm soils four months post-fire in order to examine the effects of slope and burn intensity on %C, C stocks, %N and black carbon (g kg-1 C, and g m-2). We developed and implemented the benzene polycarboxylic acid (BPCA) method for quantifying BC. With regard to slope, we found that steeper slopes had higher C : N than shallow slopes, but that there was no difference in black carbon content or stocks. BC content was greatest in the litter in burned sites (19 g kg-1 C), while BC stocks were greatest in the 5-15 cm subsurface soils (23 g m-2). At the time of sampling, none of the BC deposited on the land surface post-fire had been incorporated into to either the 0-5 cm or 5-15 cm soil layers. The ratio of B5CA : B6CA (less condensed to more condensed BC) indicated there was significantly more older, more processed BC at depth. Total BC soil stocks were relatively low compared to other fire-prone grassland and boreal forest systems, indicating most of the BC produced in this system is likely transported off the surface through erosion events. Future work examining mechanisms for BC transport will be required for understanding the role BC plays in the global carbon cycle.

  5. Comment on "Radiative Absorption Enhancements Due to the Mixing State of Atmospheric Black Carbon"

    NASA Astrophysics Data System (ADS)

    Jacobson, Mark Z.

    2013-01-01

    Cappa et al. (Reports, 31 August 2012, p. 1078) suggest that black carbon (BC) in a mixture absorbs only ~6% more sunlight than when volatile chemicals are evaporated from the mixture, and state that "many climate models may overestimate warming by BC." However, the authors misinterpret at least some model results and omit optical focusing at high relative humidity and of involatile components. Thus, their conclusion about model error is not demonstrated.

  6. Adsorption Behavior of Black Carbon for Radioactive Iodine Species in Subsurface Environments

    NASA Astrophysics Data System (ADS)

    Choung, S.; Kim, M.; Um, W.

    2012-12-01

    Releases of radioactive iodines (125/129/131I) into subsurface environments occur during nuclear power plant operations, nuclear weapons tests, and nuclear accidents such as Chernobyl and Fukushima. Environmental concern is mostly for 129I due to high toxicity and long-half life, t1/2=1,600,000 years. The fate and transport of radioactive iodines depend on the speciation in the environments. Sorption of iodate (IO3-) is strongly affected by natural organic matter (NOM) in soil/sediments, while iodide (I-) sorption is less. Although there are numerous forms and compositions of NOM in soil/sediments, previous studies were mostly focused on general organic matter such as humic and fulvic acids. The objective of this study is addressed to evaluate the impact of black carbon as different NOM forms in subsurface environments. Laboratory-produced wood char was used as a representative of black carbon for sorption batch experiments. Commercial humic acid was added to experiments for comparison of iodine sorption behavior to black carbon material. Stable iodine isotope, 127I, was used as a surrogate of radioactive iodine. The 13C-NMR analyses indicated that the wood char consisted of dominantly aromatic chemical structures, while the humic acid exhibited relatively more aliphatic structures than aromaticity. The char and humic acid significantly increased iodide and iodate sorption, respectively. However, iodate sorption on char and iodide sorption on humic acid were negligible in this study. These observations implied different sorption mechanisms between black carbon and humic acid due to different pore structures and chemical compositions. Both of sorption isotherms are dependent on aqueous concentrations, following Freundlich isotherm with n~0.7. The sorption behavior and mechanism of iodine is significantly influenced by the NOM types in soils and sediments, which can enhance iodine retardation in the subsurface environment.

  7. Determination of Effective Particle Density for Sterically Stabilized Carbon Black Particles: Effect of Diblock Copolymer Stabilizer Composition.

    PubMed

    Growney, David J; Fowler, Patrick W; Mykhaylyk, Oleksandr O; Fielding, Lee A; Derry, Matthew J; Aragrag, Najib; Lamb, Gordon D; Armes, Steven P

    2015-08-18

    Two poly(styrene-b-hydrogenated isoprene) (PS-PEP) copolymers and a poly(styrene-b-hydrogenated butadiene) (PS-PB) diblock copolymer of differing polystyrene content (20, 28 or 35 mol %) and molecular weight (117-183 kg mol(-1)) are examined. These copolymers form star-like micelles in n-dodecane, as judged by TEM, DLS, and SAXS studies. At ambient temperature, such micelles are known to adsorb intact onto a model colloidal substrate such as carbon black, conferring a high degree of dispersion (Growney, D. J.; Mykhaylyk, O. O.; Armes, S. P. Langmuir 2014, 30, 6047). Isotherms for micellar adsorption on carbon black at 20 °C are constructed using a supernatant depletion assay based on UV spectroscopy by utilizing the aromatic chromophore in the polystyrene block. Perhaps surprisingly, the diblock copolymer with the lowest polystyrene content has the strongest affinity for the carbon black particles. Assuming that the star-like diblock copolymer micelles adsorb onto carbon black to form hemi-micelles with a stabilizer layer thickness equal to the mean micelle radius, the effective particle density of the resulting sterically stabilized carbon black particles in n-dodecane can be estimated from the SAXS micelle dimensions based on geometric considerations. As an approximation, a spherical core-shell morphology was assumed, and the primary grain size of the carbon black particles was determined to be 74 nm diameter as judged by BET surface area analysis. Using this approach, effective particle densities of 0.90, 0.91, and 0.92 g cm(-3) were calculated for sterically stabilized carbon black particles prepared using the PS-PB20, PS-PEP28, and PS-PEP35 diblock copolymers, respectively. These densities are significantly lower than that of carbon black (1.89 g cm(-3)), which indicates that the sterically stabilized carbon black particles are substantially solvated. Since the rate of sedimentation of the sterically stabilized carbon black particles depends on the density

  8. Airborne remote sensing of photosynthetic light use efficiency and carbon uptake along an Arctic transect in Finland

    NASA Astrophysics Data System (ADS)

    Atherton, J.; Hill, T. C.; Prieto-Blanco, A.; Wade, T.; Clement, R.; Moncrieff, J.; Williams, M. D.; Disney, M.; Nichol, C. J.

    2009-12-01

    It is critical to understand the dynamics of ecosystem carbon uptake through seasonal changes and in response to environmental drivers. In this study we utilised aircraft based remote sensing and CO2/H2O flux monitoring systems to quantify changes in photosynthesis along an Arctic transect. The University of Edinburgh's (UK) research aircraft (a Diamond HK 36 TTC-ECO Dimona) was deployed in the Arctic during summer 2008 to carry out a series of transect-flights over a birch-mire mosaic site near Kevo, Finland as part of the Arctic Biosphere Atmosphere Coupling at Multiple Scales (ABACUS) project. The aircraft is equipped with automated dual field-of-view (hyperspectral) radiometers and CO2/H2O flux and meteorological instrumentation. Vegetation indices known to be related to photosynthetic light use efficiency (LUE), including the well established Photochemical Reflectance Index (PRI) and Solar-induced Fluorescence (SiF) as well as the Normalized Difference Vegetation Index (NDVI) were calculated from the spectral data and matched in space to the CO2 flux measurements. We explored spatial relationships between NDVI and CO2 flux, LUE (CO2 flux / Absorbed Photosynthetically Active Radiation) and PRI and finally SiF (calculated using the Fraunhofer infilling method) and relevant environmental drivers. Our results highlight the unique ability of an airborne platform to quantify ecosystem physiology across a landscape and demonstrate how such measurements can bridge the spatial gap between ground and satellite-based observations.

  9. Online single particle measurements of black carbon coatings, structure and optical properties

    NASA Astrophysics Data System (ADS)

    Allan, James; Liu, Dantong; Taylor, Jonathan; Flynn, Michael; Williams, Paul; Morgan, William; Whitehead, James; Alfarra, Rami; McFiggans, Gordon; Coe, Hugh

    2016-04-01

    The impacts of black carbon on meteorology and climate remain a major source of uncertainty, owing in part to the complex relationship between the bulk composition of the particulates and their optical properties. A particular complication stems from how light interacts with particles in response to the microphysical configuration and any 'coatings', i.e. non-black carbon material that is either co-emitted or subsequently obtained through atmospheric processing. This may cause the particle to more efficiently absorb or scatter light and may even change the sign of its radiative forcing potential. While much insight has been gained through measurements of bulk aerosol properties, either while suspended or after collection on a filter or impactor substrate, this does not provide a complete picture and thus may not adequately constrain the system. Here we present an overview of recent work to better constrain the properties of black carbon using online, in situ measurements of single particles, primarily using a Single Particle Soot Photometer (SP2). We have developed novel methods of inverting the data produced and combining the different metrics derived so as to give the most effective insights into black carbon sources, processes and properties. We have also used this measurement in conjunction with other instruments (sometimes in series) and used the data to challenge many commonly used models of optical properties such as core-shell Mie, Rayleigh-Debeye-Gans and effective medium. This work has been carried out in a variety of atmospheric environments and with laboratory-produced soots, e.g. from a diesel engine rig. Highlights include the finding that with real-world atmospheric aerosols, bulk optical measurements may be insufficient to derive brown carbon parameters without detailed morphological data. We also show that the enhancement of absorption for both ambient and laboratory generated particles only occurs after the coating mass fraction reaches a certain

  10. Preparation of activated carbon with large specific surface area from reed black liquor.

    PubMed

    Sun, Y; Zhang, J P; Yang, G; Li, Z H

    2007-05-01

    Activated carbon with large specific surface area and well-developed porosity was prepared from pyrolysis of K2CO3-impregnated lignin precipitated from reed pulp black liquors. The impregnation ratio was 1:1. The effect of activation temperature upon the Brunauer-Emmett-Teller (BET) specific surface area and pore volume of the carbon was closely investigated. Increasing activation temperature led to an opening and widening of the porous structure below 800'C. Above 800'C, the excess widening of pore led to the decrease of BET surface area and micropore volume. The BET surface area and pore volume of the carbon activated at 800 degrees C were 1395 m(2) g(-1) and 0.7702 ml g(-1) , respectively. The potential application of the carbon activated at 800 degrees C for removal of Cr (VI) was also investigated. The experimental results showed that it had good adsorption capacity. PMID:17615958

  11. Carbon and char residue yields from rapid pyrolysis of kraft black liquor.

    PubMed

    Sricharoenchaikul, V; Hicks, A L; Frederick, W J

    2001-04-01

    The yields of char residue, fixed carbon, and inorganic carbonate were measured for oxidized black liquor char residues produced in a laboratory laminar entrained-flow reactor (LEFR) at heating rates of 4000-13,000 degrees C/s. The char residue yields at the end of devolatilization thus obtained decreased nearly linearly with temperature, from 75% at 700 degrees C to 58% at 1100 degrees C. There were explainable differences in the char residue yields from the liquor used in this study and those used in other studies. Char residue yields seemed to depend mainly on the temperature to which the particles or droplets were exposed and were not very sensitive to heating rate. Fixed carbon yields behaved similarly to those of the char residue. The fixed carbon remaining at the end of devolatilization decreased from 67% at 700 degrees C to about 45% at 1100 degrees C. The carbonate content in black liquor changed very little before and after devolatilization. PMID:11272019

  12. Coatings of black carbon in Tijuana, Mexico, during the CalMex Campaign

    NASA Astrophysics Data System (ADS)

    Takahama, S.; Russell, L. M.; Duran, R.; Subramanian, R.; Kok, G.

    2010-12-01

    Black carbon number and mass concentrations were measured by a single-particle soot photometer (SP2; by Droplet Measurement Technologies) in Tijuana, Mexico between May 15, 2010, and June 30, 2010, for the CalMex campaign. The measurement site, Parque Morelos, is a recreational area located in the Southeast region of Tijuana. The SP2 was equipped with 8-channels of signal detection that spans a wider range of sensitivity for incandescing and scattering measurements than traditional configurations. The campaign-average number concentration of incandescing particles was 280 #/cc, peaking during traffic activity in the mornings. Incandescing particles made up 50% of all particles (incandescing and purely scattering) detected by the SP2. The mode of the number size distribution estimated for black carbon, according to estimated mass-equivalent diameters, was approximately 100 nm or smaller. Temporal variations in estimated coating thicknesses for these black carbon particles are discussed together with co-located measurements of organic aerosol and inorganic salts.

  13. Distinctive sorption mechanisms of 4-chlorophenol with black carbons as elucidated by different pH.

    PubMed

    Shih, Yang-hsin; Su, Yuh-fan; Ho, Ren-yu; Su, Po-hsin; Yang, Chien-ying

    2012-09-01

    Black carbon (BC) has been considered as an important sorbent in the environment in recent years due to its high sorption capacity and unique sorption behavior. Sorption characteristics of black carbons from two main sources were investigated to get a better understanding of organic chemical fate in the environment. The present study showed sorption mechanisms of 4-chlorophenol, a common organic contaminant in the surroundings, in two kinds of black carbons, soot surrogate (BC1) and environmental char (BC2) derived from rice straw. Sorption capacity of 4-chlorophenol was much higher in BC1 than on BC2 due to the larger surface area of BC1. However, the surface-area normalized sorption coefficients (sorption capacity per surface area) of BC2 were higher than those of BC1, indicating electrostatic attraction and actions of polar foundational groups on BC2 can react with 4-chlorophenol. With increasing temperature, sorption of BC1 decreased but the sorption of BC2 significantly increased at pH 10 and only slightly increased at pH 4. An exothermic sorption reaction was found for BC1; however, an endothermic reaction of chemical sorption occurred on BC2 at pH 10 due to the electrostatic attraction. At pH4, sorption capacity of BC2 decreased and the small positive sorption enthalpy indicated that less electrostatic attractions occurred because of the neutral form of 4-chlorophenol and the domination of mainly hydrophobic interactions. PMID:22842752

  14. Polypyrrole/carbon black composite as a novel oxygen reduction catalyst for microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Yuan, Yong; Zhou, Shungui; Zhuang, Li

    A polypyrrole/carbon black (Ppy/C) composite has been employed as an electrocatalyst for the oxygen reduction reaction (ORR) in an air-cathode microbial fuel cell (MFC). The electrocatalytic activity of the Ppy/C is evaluated toward the oxygen reduction using cyclic voltammogram and linear sweep voltammogram methods. In comparison with that at the carbon black electrode, the peak potential of the ORR at the Pp/C electrode shifts by approximate 260 mV towards positive potential, demonstrating the electrocatalytic activity of Ppy toward ORR. Additionally, the results of the MFC experiments show that the Ppy/C is well suitable to fully substitute the traditional cathode materials in MFCs. The maximum power density of 401.8 mW m -2 obtained from the MFC with a Ppy/C cathode is higher than that of 90.9 mW m -2 with a carbon black cathode and 336.6 mW m -2 with a non-pyrolysed FePc cathode. Although the power output with a Ppy/C cathode is lower than that with a commercial Pt cathode, the power per cost of a Ppy/C cathode is 15 times greater than that of a Pt cathode. Thus, the Ppy/C can be a good alternative to Pt in MFCs due to the economic advantage.

  15. Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice

    SciTech Connect

    Tong Haiyan McGee, John K.; Saxena, Rajiv K.; Kodavanti, Urmila P.; Devlin, Robert B.; Gilmour, M. Ian

    2009-09-15

    Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 {mu}g of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 {mu}g LPS. 24 hours later, pulmonary inflammatory responses and cardiac effects were assessed by bronchoalveolar lavage and isolated cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Additional mice were assessed for histological changes in lung and heart. Instillation of 40 {mu}g of AF-SWCNTs, UFCB and AF-UFCB increased percentage of pulmonary neutrophils. No significant effects were observed at the lower particle concentration. Sporadic clumps of particles from each treatment group were observed in the small airways and interstitial areas of the lungs according to particle dose. Patches of cellular infiltration and edema in both the small airways and in the interstitium were also observed in the high dose group. Isolated perfused hearts from mice exposed to 40 {mu}g of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than other particle-exposed animals and controls, and also exhibited signs of focal cardiac myofiber degeneration. No particles were detected in heart tissue under light microscopy. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects only with the AF-carbon

  16. Assessment of EDGAR emission inventory using carbon monoxide (CO) MOZAIC/IAGOS airborne measurements over Europe

    NASA Astrophysics Data System (ADS)

    Boschetti, Fabio; Chen, Huilin; Marshall, Julia; Gerbig, Christoph; Thouret, Valerie; Nedelec, Philippe

    2014-05-01

    The main advantage of using airborne data is their ability to collect mole fraction measurements covering most of the troposphere. However, mainly due to the cost of rental aircraft, the number of flights is usually quite limited, with direct consequences on measurement availability. Making use of commercial airliners, the MOZAIC/IAGOS program provides CO mole fraction measurements on a regular basis, avoiding this disadvantage. In this study MOZAIC/IAGOS measurements have been used together with a Lagrangian particle dispersion model (STILT) to evaluate the representativeness of the EDGAR version-4.2 emission inventory at 3 different locations (Frankfurt, Paris and Vienna) for the time frame 2004-2011. We make use of the concept of the mixed layer, where signals resulting from CO emissions are reasonable well mixed, and lead to an enhancement of CO within the mixed layer. We investigate the CO enhancement relative to values in the free troposphere (specifically at two km above the mixing height), for both the upper and lower half of the mixed layer. The hypothesis is that the CO enhancement in the upper half of the mixed layer is more representative for larger spatial scales, as the vertical distance to the surface and its emission sources is increased compared to that of the lower half. CO enhancements calculated from CO mole fractions modeled by STILT coupled with the emission inventory at 10 km horizontal resolution are compared with the corresponding values from observed CO mole fractions for both the lower and the upper half of the mixed layer. The transport model domain is roughly coincident with the EU territory; simulations show that most of the Lagrangian particles exit the domain to the north and to the west. On these sides of the domain, boundaries are represented by oceans, characterized by small CO vertical gradients. Modeled global CO fields from the MACC project will be used in this study as lateral boundary conditions. We found that the simulation

  17. Spatial Variability in Black Carbon Mixing State Observed During The Multi-City NASA DISCOVER-AQ Field Campaign

    NASA Astrophysics Data System (ADS)

    Moore, R.; Ziemba, L. D.; Beyersdorf, A. J.; Chen, G.; Corr, C.; Hudgins, C.; Martin, R.; Shook, M.; Thornhill, K. L., II; Winstead, E.; Anderson, B. E.

    2014-12-01

    Light absorbing carbonaceous aerosols are known to be an important climatic driver with a global radiative forcing of about half (IPCC, 2013) to two-thirds (Bond et al., 2013) that of the dominant greenhouse gas, carbon dioxide. While the mass absorption coefficient of pure black carbon (BC) is fairly well known, observational evidence suggests that BC rapidly mixes with other aerosol chemical components within hours of emission (Moffet and Prather, 2009; Moteki et al., 2007). These other components may include predominantly scattering organic, sulfate, and nitrate species, as well as light-absorbing, so-called "brown carbon" (BrC). It has been suggested that the presence of these BC-mixed components may induce mixing-state-dependent lensing effects that could potentially double the BC direct radiative forcing (Jacobson, 2001). The key to better understanding how BC-rich aerosols are distributed in the atmosphere is to examine an unbiased set of measurements covering broad spatial and temporal coverage; however, many past airborne field campaigns have specifically targeted source plumes or other scientifically-relevant emissions sources. The recent NASA DISCOVER-AQ campaign is unique in that approximately the same flight pattern was performed over a month-long period in each of four different U.S. metropolitan areas, ensuring an unbiased, or at least less biased, data set with both wide horizontal and vertical (surface to 5 km altitude) coverage. We present a statistical analysis of BC-rich particle mixing state measured during DISCOVER-AQ by a DMT Single Particle Soot Photometer (SP2). The SP2 measures the BC mass distribution via laser incandescence, and the non-BC coating thickness is inferred from the light scattering signal of particles greater than 200 nm in diameter (Gao et al., 2007; Moteki and Kondo, 2008). The SP2-derived size distributions are compared to optical scattering size distributions measured by an UHSAS in order determine 1) the externally

  18. Double-pulse 2-μm integrated path differential absorption lidar airborne validation for atmospheric carbon dioxide measurement.

    PubMed

    Refaat, Tamer F; Singh, Upendra N; Yu, Jirong; Petros, Mulugeta; Remus, Ruben; Ismail, Syed

    2016-05-20

    Field experiments were conducted to test and evaluate the initial atmospheric carbon dioxide (CO2) measurement capability of airborne, high-energy, double-pulsed, 2-μm integrated path differential absorption (IPDA) lidar. This IPDA was designed, integrated, and operated at the NASA Langley Research Center on-board the NASA B-200 aircraft. The IPDA was tuned to the CO2 strong absorption line at 2050.9670 nm, which is the optimum for lower tropospheric weighted column measurements. Flights were conducted over land and ocean under different conditions. The first validation experiments of the IPDA for atmospheric CO2 remote sensing, focusing on low surface reflectivity oceanic surface returns during full day background conditions, are presented. In these experiments, the IPDA measurements were validated by comparison to airborne flask air-sampling measurements conducted by the NOAA Earth System Research Laboratory. IPDA performance modeling was conducted to evaluate measurement sensitivity and bias errors. The IPDA signals and their variation with altitude compare well with predicted model results. In addition, off-off-line testing was conducted, with fixed instrument settings, to evaluate the IPDA systematic and random errors. Analysis shows an altitude-independent differential optical depth offset of 0.0769. Optical depth measurement uncertainty of 0.0918 compares well with the predicted value of 0.0761. IPDA CO2 column measurement compares well with model-driven, near-simultaneous air-sampling measurements from the NOAA aircraft at different altitudes. With a 10-s shot average, CO2 differential optical depth measurement of 1.0054±0.0103 was retrieved from a 6-km altitude and a 4-GHz on-line operation. As compared to CO2 weighted-average column dry-air volume mixing ratio of 404.08 ppm, derived from air sampling, IPDA measurement resulted in a value of 405.22±4.15  ppm with 1.02% uncertainty and

  19. Airborne radioactivity survey of parts of Baggs SW and Baggs SE quadrangles, Carbon and Sweetwater counties, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 151 square miles of Baggs SW and Baggs SE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater counties by the U.S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission. The survey was made with scintillation detection equipment mounted in a C-47 aircraft and consisted of parallel east-west flight lines spaced at quarter mile intervals, flown approximately 500 feet above the ground. Aerial photographs were used for pilot guidance, and the flight path of the aircraft was recorded by a gyrostabilized, continuous-strip-film camera. The distance of the aircraft from the ground was measured with a continuously recording radio altimeter. The width of the zone on the ground form which the anomalous radiation is measured at the nominal 500 foot flight altitude varied with the areal extent and the intensity of radioactivity of the source. For strong sources of radioactivity the width of the zone may be as much as 1,400 feet. Thus, quarter mile spacing of the flight lines would be adequate to detect anomalies from strong sources of radioactivity; however, small areas of considerable radioactivity midway between flight lines may not be noted. The approximate locations of twelve radioactivity anomalies are shown on the accompanying map. The plotted position of the anomalies may be in error by as much as a quarter mile owing to the errors in available base maps or to the existence of areas on the base maps up to several square miles in which it is impossible to find and plot recognizable landmarks. The present technique of airborne radioactivity measurement does not permit distinguishing between activity due to thorium and that due to uranium. An anomaly, therefore, may represent radioactivity due entirely to one or to a combination of these elements. The radioactivity

  20. Decreased albedo, e-folding depth and photolytic OH radical and NO2 production with increasing black carbon content in Arctic snow

    NASA Astrophysics Data System (ADS)

    Reay, H. J.; France, J. L.; King, M. D.

    2012-07-01

    The contribution of snow photochemistry to snow and atmospheric oxidative capacity is controlled, in part, by snow albedo and e-folding depths in snow. Albedo ande-folding depths (and thus snow photochemistry) are a function of black carbon concentration in snow. The paper presented here demonstrates the complicated response of albedo, e-folding depth (wavelengths 300-600 nm) and depth-integrated production rates of NO2and OH radicals to increasing black carbon concentration in well-characterized snowpacks of the Barrow OASIS campaign, Alaska. All snowpacks were reworked layered windpacks and were found to have similar responses to changes in black carbon concentration. The radiative-transfer calculations demonstrate two light absorption regimes: ice-dominated and black carbon dominated. The ice-dominated and black carbon dominated behavior of albedo,e-folding depth and depth-integrated production rates with increasing black carbon concentrations are presented. For black carbon concentrations greater than 20 ng g-1 (wavelength range of 300-600 nm), e-folding depth and depth-integrated production rate have an inverse power law relationship with black carbon concentration. Doubling the black carbon concentration decreases thee-folding depth to ˜70% of the initial value and for solar zenith angles greater than 60°, doubling the black carbon concentration decreases depth-integrated production rates of NO2 and OH to ˜70% and ˜65% of their original values respectively.

  1. Estimating absorbing black carbon and organic carbon optical properties from AERONET and MISR data over East Asia

    NASA Astrophysics Data System (ADS)

    Chen, B.; Ramanathan, V.; Huang, J.; Zhang, G. J.; Xu, Y.

    2011-12-01

    The radiative forcing due to carbonaceous aerosols is one of the largest source of uncertainties in global and regional climate change. Black carbon and organic carbon from biomass and fossil fuel are two major types of carbonaceous aerosols. In this study we use available ground based and satellite observations to infer the optical properties of black and organic carbon. NASA's AERONET and MISR data over East Asia provide the observational basis. We use the spectral variations in the observed aerosol extinction optical depth and absorption optical depth to categorize the optical properties including their mixing state with other aerosols such as dust and other inorganic aerosols. We create 8 different categories of aerosol mixtures: Dust, Biomass Burning, Fossil Fuel, Aged Fossil Fuel, Mixed Dust with Biomass Burning, Mixed Dust with Aged Fossil Fuel, Mixed Biomass Burning with Fossil Fuel, and Mixed Dust, Biomass Burning, with Fossil Fuel, over the following 6 regions of East Asia: Nepal, Gobi, North Industrial China, South Industrial China, Southeast Asia, and Korea/Japan. Our results are compared with independent surface observations over China using Aethalometers and Single Particle Soot Photometers.

  2. Implications of ammonia emissions from post-combustion carbon capture for airborne particulate matter.

    PubMed

    Heo, Jinhyok; McCoy, Sean T; Adams, Peter J

    2015-04-21

    Amine scrubbing, a mature post-combustion carbon capture and storage (CCS) technology, could increase ambient concentrations of fine particulate matter (PM2.5) due to its ammonia emissions. To capture 2.0 Gt CO2/year, for example, it could emit 32 Gg NH3/year in the United States given current design targets or 15 times higher (480 Gg NH3/year) at rates typical of current pilot plants. Employing a chemical transport model, we found that the latter emission rate would cause an increase of 2.0 μg PM2.5/m(3) in nonattainment areas during wintertime, which would be troublesome for PM2.5-burdened areas, and much lower increases during other seasons. Wintertime PM2.5 increases in nonattainment areas were fairly linear at a rate of 3.4 μg PM2.5/m(3) per 1 Tg NH3, allowing these results to be applied to other CCS emissions scenarios. The PM2.5 impacts are modestly uncertain (±20%) depending on future emissions of SO2, NOx, and NH3. The public health costs of CCS NH3 emissions were valued at $31-68 per tonne CO2 captured, comparable to the social cost of carbon itself. Because the costs of solvent loss to CCS operators are lower than the social costs of CCS ammonia, there is a regulatory interest to limit ammonia emissions from CCS. PMID:25811231

  3. Bulk and surface structural investigations of diesel engine soot and carbon black.

    PubMed

    Müller, J-O; Su, D S; Wild, U; Schlögl, R

    2007-08-14

    The microstructure and electronic structure of environmentally relevant carbons such as Euro IV heavy duty diesel engine soot, soot from a black smoking diesel engine, spark discharge soot as model aerosol, commercial furnace soot and lamp black are investigated by transmission electron microscopy, electron energy-loss spectroscopy and X-ray photoelectron spectroscopy. The materials exhibit differences in the predominant bonding, which influences microstructure as well as surface functionalization. These chemical and physical properties depend on the formation history of the investigated carbonaceous materials. In this work, a correlation of the microstructure of the samples to the predominant bonding and incorporation of oxygen into the carbons is obtained. It is shown that a high amount of defects and the deviation of the carbons from a perfect graphitic structure results in a increased incorporation of oxygen and hydrogen. A correlation between the length and curvature of graphene layers with the bonding state of carbon atoms and incorporation of oxygen and hydrogen is established. PMID:17646891

  4. Gasification behavior of carbon residue in bed solids of black liquor gasifier

    SciTech Connect

    Preto, Fernando; Zhang, Xiaojie; Wang, Jinsheng

    2008-07-15

    Steam gasification of carbon residue in bed solids of a low-temperature black liquor gasifier was studied using a thermogravimetric system at 3 bar. Complete gasification of the carbon residue, which remained unreactive at 600 C, was achieved in about 10 min as the temperature increased to 800 C. The rate of gasification and its temperature dependence were evaluated from the non-isothermal experiment results. Effects of particle size and adding H{sub 2} and CO to the gasification agent were also studied. The rate of steam gasification could be taken as zero order in carbon until 80% of carbon was gasified, and for the rest of the gasification process the rate appeared to be first order in carbon. The maximum rate of carbon conversion was around 0.003/s and the activation energy was estimated to be in the range of 230-300 kJ/mol. The particle size did not show significant effect on the rate of gasification. Hydrogen and carbon monoxide appeared to retard the onset of the gasification process. (author)

  5. Black Carbon in Estuarine (Coastal) High-molecular-weight Dissolved Organic Matter

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Dissolved organic matter (DOM) in the ocean constitutes one of the largest pools of organic carbon in the biosphere, yet much of its composition is uncharacterized. Observations of black carbon (BC) particles (by-products of fossil fuel combustion and biomass burning) in the atmosphere, ice, rivers, soils and marine sediments suggest that this material is ubiquitous, yet the contribution of BC to the ocean s DOM pool remains unknown. Analysis of high-molecular-weight DOM isolated from surface waters of two estuaries in the northwest Atlantic Ocean finds that BC is a significant component of DOM, suggesting that river-estuary systems are important exporters of BC to the ocean through DOM. We show that BC comprises 4-7% of the dissolved organic carbon (DOC) at coastal ocean sites, which supports the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition. Flux calculations suggest that BC could be as important as vascular plant-derived lignin in terms of carbon inputs to the ocean. Production of BC sequesters fossil fuel- and biomass-derived carbon into a refractory carbon pool. Hence, BC may represent a significant sink for carbon to the ocean.

  6. Comparison of Toxicity and Deposition of Nano-Sized Carbon Black Aerosol Prepared With or Without Dispersing Sonication

    PubMed Central

    Kang, Mingu; Han, Jeong-Hee

    2013-01-01

    Nanotoxicological research has shown toxicity of nanomaterials to be inversely related to particle size. However, the contribution of agglomeration to the toxicity of nanomaterials has not been sufficiently studied, although it is known that agglomeration is associated with increased nanomaterial size. In this study, we prepared aerosols of nano-sized carbon black by 2 different ways to verify the effects of agglomeration on the toxicity and deposition of nano-sized carbon black. The 2 methods of preparation included the carbon black dispersion method that facilitated clustering without sonication and the carbon black dispersion method involving sonication to achieve scattering and deagglomeration. Male Sprague-Dawley rats were exposed to carbon black aerosols 6 hr a day for 3 days or for 2 weeks. The median mass aerodynamic diameter of carbon black aerosols averaged 2.08 μm (for aerosol prepared without sonication; group N) and 1.79 μm (for aerosol prepared without sonication; group S). The average concentration of carbon black during the exposure period for group N and group S was 13.08 ± 3.18 mg/m3 and 13.67 ± 3.54 mg/ m3, respectively, in the 3-day experiment. The average concentration during the 2-week experiment was 9.83 ± 3.42 mg/m3 and 9.08 ± 4.49 mg/m3 for group N and group S, respectively. The amount of carbon black deposition in the lungs was significantly higher in group S than in group N in both 3-day and 2-week experiments. The number of total cells, macrophages and polymorphonuclear leukocytes in the bronchoalveolar lavage (BAL) fluid, and the number of total white blood cells and neutrophils in the blood in the 2- week experiment were significantly higher in group S than in normal control. However, differences were not found in the inflammatory cytokine levels (IL-1β, TNF-α, IL-6, etc.) and protein indicators of cell damage (albumin and lactate dehydrogenase) in the BAL fluid of both group N and group S as compared to the normal control. In

  7. Enhanced light absorption by mixed source black and brown carbon particles in UK winter

    PubMed Central

    Liu, Shang; Aiken, Allison C.; Gorkowski, Kyle; Dubey, Manvendra K.; Cappa, Christopher D.; Williams, Leah R.; Herndon, Scott C.; Massoli, Paola; Fortner, Edward C.; Chhabra, Puneet S.; Brooks, William A.; Onasch, Timothy B.; Jayne, John T.; Worsnop, Douglas R.; China, Swarup; Sharma, Noopur; Mazzoleni, Claudio; Xu, Lu; Ng, Nga L.; Liu, Dantong; Allan, James D.; Lee, James D.; Fleming, Zoë L.; Mohr, Claudia; Zotter, Peter; Szidat, Sönke; Prévôt, André S. H.

    2015-01-01

    Black carbon (BC) and light-absorbing organic carbon (brown carbon, BrC) play key roles in warming the atmosphere, but the magnitude of their effects remains highly uncertain. Theoretical modelling and laboratory experiments demonstrate that coatings on BC can enhance BC's light absorption, therefore many climate models simply assume enhanced BC absorption by a factor of ∼1.5. However, recent field observations show negligible absorption enhancement, implying models may overestimate BC's warming. Here we report direct evidence of substantial field-measured BC absorption enhancement, with the magnitude strongly depending on BC coating amount. Increases in BC coating result from a combination of changing sources and photochemical aging processes. When the influence of BrC is accounted for, observationally constrained model calculations of the BC absorption enhancement can be reconciled with the observations. We conclude that the influence of coatings on BC absorption should be treated as a source and regionally specific parameter in climate models. PMID:26419204

  8. Carbon nanowalls: the next step for physical manifestation of the black body coating

    PubMed Central

    Krivchenko, V. A.; Evlashin, S. A.; Mironovich, K. V.; Verbitskiy, N. I.; Nefedov, A.; Wöll, C.; Kozmenkova, A. Ya.; Suetin, N. V.; Svyakhovskiy, S. E.; Vyalikh, D. V.; Rakhimov, A. T.; Egorov, A. V.; Yashina, L. V.

    2013-01-01

    The optical properties of carbon nanowall (CNW) films in the visible range have been studied and reported for the first time. Depending on the film structure, ultra-low total reflectance up to 0.13% can be reached, which makes the CNW films a promising candidate for the black body-like coating, and thus for a wide range of applications as a light absorber. We have estimated important trends in the optical property variation from sample to sample, and identified the presence of edge states and domain boundaries in carbon nanowalls as well as the film mass density variation as the key factors. Also we demonstrated that at much lower film thickness and density than for a carbon nanotube forest the CNWs yield one order higher specific light absorption. PMID:24270355

  9. Spatial patterns of vegetation biomass and soil organic carbon acquired from airborne lidar and hyperspectral imagery at Reynolds Creek Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Will, R. M.; Li, A.; Glenn, N. F.; Benner, S. G.; Spaete, L.; Ilangakoon, N. T.

    2015-12-01

    Soil organic carbon distribution and the factors influencing this distribution are important for understanding carbon stores, vegetation dynamics, and the overall carbon cycle. Linking soil organic carbon (SOC) with aboveground vegetation biomass may provide a method to better understand SOC distribution in semiarid ecosystems. The Reynolds Creek Critical Zone Observatory (RC CZO) in Idaho, USA, is approximately 240 square kilometers and is situated in the semiarid Great Basin of the sagebrush-steppe ecosystem. Full waveform airborne lidar data and Next-Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-ng) collected in 2014 across the RC CZO are used to map vegetation biomass and SOC and then explore the relationships between them. Vegetation biomass is estimated by identifying vegetation species, and quantifying distribution and structure with lidar and integrating the field-measured biomass. Spectral data from AVIRIS-ng are used to differentiate non-photosynthetic vegetation (NPV) and soil, which are commonly confused in semiarid ecosystems. The information from lidar and AVIRIS-ng are then used to predict SOC by partial least squares regression (PLSR). An uncertainty analysis is provided, demonstrating the applicability of these approaches to improving our understanding of the distribution and patterns of SOC across the landscape.

  10. The origin of black carbon on speleothems in tourist caves in South Korea: Chemical characterization and source discrimination by radiocarbon measurement

    NASA Astrophysics Data System (ADS)

    Chang, Sae Jung; Jeong, Gi Young; Kim, Soo Jin

    Since the Gosu, Ondal, and Sungryu karst caves in South Korea became open to the public several decades ago, the surface of their speleothems has been turning black due to pollutants. The black pollutant is concentrated at the surface of speleothems, and the surface black layer is 0.1 to several millimeters thick. Elemental measurements of three bulk, acid-dissolved and oxidized fractions of the surface black layer show that the black pigment is a black carbon. The black carbon correlates positively with sulfates, nitrates, manganese, and lead, which are typical tracers of industrial and urban emissions. The 14C-measurement of the black carbon, using accelerator mass spectrometry, shows that the black carbon was derived from both fossil-fuel combustion and biomass burning in roughly equal amounts, evidenced by fC value ranging from 0.340 to 0.592 (<±0.004, 1 σ). Therefore, protection of speleothems from black coloration requires control of anthropogenic black carbons carried by visitors. Suitable measures might include closure of caves, air cleaning of visitors and regulation of visitor numbers. The application of radiocarbon measurement of black carbon suggests that the fC is a valuable proxy for tracing the blackening phenomenon of natural and cultural heritage sites such as caves.

  11. Environmental Technology Verification Program Advanced Monitoring Systems Center Quality Assurance Project Plan for Verification of Black Carbon Monitors

    EPA Science Inventory

    Black carbon is a term that is commonly used to describe strongly light absorbing carbon (LAC), which is thought to play a significant role in global climate change through direct absorption of light, interaction with clouds, and by reducing the reflectivity of snow and ice. BC ...

  12. Rethinking the Scope of Environmental Injustice: Perceptions of Health Hazards in a Rural Native American Community Exposed to Carbon Black

    ERIC Educational Resources Information Center

    Shriver, Thomas E.; Webb, Gary R.

    2009-01-01

    We use in-depth interviews, participant observation, and document analysis to examine perceptions of environmental health and justice among Native Americans in a rural Oklahoma community. Residents live near the Continental Carbon Company, which manufactures a rubber compound know as "carbon black." Ponca tribal members believe their respiratory…

  13. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    NASA Astrophysics Data System (ADS)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-10-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil-fuel and biomass-burning BC. In addition we develop a global simulation of brown carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of 2. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in absorption aerosol optical depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with the largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 Wm-2 (0.08 Wm-2 from anthropogenic sources and 0.05 Wm-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 Wm-2, with an additional +0.11 Wm-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80%/+140%. Our estimates are at the lower end of the 0.2-1.0 Wm-2 range from previous studies, and substantially less than the +0.6 Wm-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime (including the

  14. Exploiting simultaneous observational constraints on mass and absorption to estimate the global direct radiative forcing of black carbon and brown carbon

    NASA Astrophysics Data System (ADS)

    Wang, X.; Heald, C. L.; Ridley, D. A.; Schwarz, J. P.; Spackman, J. R.; Perring, A. E.; Coe, H.; Liu, D.; Clarke, A. D.

    2014-06-01

    Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand a global model simulation (GEOS-Chem) of BC to include the absorption enhancement associated with BC coating and separately treat both the aging and physical properties of fossil fuel and biomass burning BC. In addition we develop a global simulation of Brown Carbon (BrC) from both secondary (aromatic) and primary (biomass burning and biofuel) sources. The global mean lifetime of BC in this simulation (4.4 days) is substantially lower compared to the AeroCom I model means (7.3 days), and as a result, this model captures both the mass concentrations measured in near-source airborne field campaigns (ARCTAS, EUCAARI) and surface sites within 30%, and in remote regions (HIPPO) within a factor of two. We show that the new BC optical properties together with the inclusion of BrC reduces the model bias in Absorption Aerosol Optical Depth (AAOD) at multiple wavelengths by more than 50% at AERONET sites worldwide. However our improved model still underestimates AAOD by a factor of 1.4 to 2.8 regionally, with largest underestimates in regions influenced by fire. Using the RRTMG model integrated with GEOS-Chem we estimate that the all-sky top-of-atmosphere DRF of BC is +0.13 W m-2 (0.08 W m-2 from anthropogenic sources and 0.05 W m-2 from biomass burning). If we scale our model to match AERONET AAOD observations we estimate the DRF of BC is +0.21 W m-2, with an additional +0.11 W m-2 of warming from BrC. Uncertainties in size, optical properties, observations, and emissions suggest an overall uncertainty in BC DRF of -80% / +140%. Our estimates are at the lower end of the 0.2-1.0 W m-2 range from previous studies, and substantially less than the +0.6 W m-2 DRF estimated in the IPCC 5th Assessment Report. We suggest that the DRF of BC has previously been overestimated due to the overestimation of the BC lifetime and the

  15. Light-absorbing properties of ambient black carbon and brown carbon from fossil fuel and biomass burning sources

    NASA Astrophysics Data System (ADS)

    Healy, R. M.; Wang, J. M.; Jeong, C.-H.; Lee, A. K. Y.; Willis, M. D.; Jaroudi, E.; Zimmerman, N.; Hilker, N.; Murphy, M.; Eckhardt, S.; Stohl, A.; Abbatt, J. P. D.; Wenger, J. C.; Evans, G. J.

    2015-07-01

    The optical properties of ambient black carbon-containing particles and the composition of their associated coatings were investigated at a downtown site in Toronto, Canada, for 2 weeks in June 2013. The objective was to assess the relationship between black carbon (BC) coating composition/thickness and absorption. The site was influenced by emissions from local vehicular traffic, wildfires in Quebec, and transboundary fossil fuel combustion emissions in the United States. Mass concentrations of BC and associated nonrefractory coatings were measured using a soot particle-aerosol mass spectrometer (SP-AMS), while aerosol absorption and scattering were measured using a photoacoustic soot spectrometer (PASS). Absorption enhancement was investigated both by comparing ambient and thermally denuded PASS absorption data and by relating absorption data to BC mass concentrations measured using the SP-AMS. Minimal absorption enhancement attributable to lensing at 781 nm was observed for BC using both approaches. However, brown carbon was detected when the site was influenced by wildfire emissions originating in Quebec. BC coating to core mass ratios were highest during this period (~7), and while direct absorption by brown carbon resulted in an absorption enhancement at 405 nm (>2.0), no enhancement attributable to lensing at 781 nm was observed. The efficiency of BC coating removal in the denuder decreased substantially when wildfire-related organics were present and may represent an obstacle for future similar studies. These findings indicate that BC absorption enhancement due to lensing is minimal for downtown Toronto, and potentially other urban locations, even when impacted by long-range transport events.

  16. Airborne tunable diode laser sensor for high-precision concentration and flux measurements of carbon monoxide and methane

    NASA Technical Reports Server (NTRS)

    Sachse, G. W.; Collins, J. E., Jr.; Hill, G. F.; Wade, L. O.; Burney, L. G.; Ritter, J. A.

    1991-01-01

    An airborne tunable diode laser instrument is described that is capable of operating in two measurement modes. One mode provides high precision (0.1 percent CH4; 1 percent CO) measurements of CH4 and CO with a 5 second response time, and a second mode achieves the very fast response time that is necessary to make airborne eddy correlation flux measurements. Examples of data from atmospheric expeditions of the Global Tropospheric Experiment are presented.

  17. Terrestrial radioisotopes in black shale hosted Mn-carbonate deposit (Úrkút, Hungary)

    NASA Astrophysics Data System (ADS)

    Vigh, Tamás; Kovács, Tibor; Somlai, János; Kávási, Norbert; Polgári, Márta; Bíró, Lóránt

    2013-08-01

    Previously, little attention has been paid to terrestrial radioisotopes (U, Th, 40K) occurring in manganese ores, despite the fact that the biogeochemical relationship between Mn and U is versatile. Occurrence of terrestrial radioisotopes in great amounts during mining on a long-term causes significant radiation exposure. It is important to inspect black shale-hosted manganese ores from this aspect, as black shales are typically potential U-rich formations. Despite the increased radon concentration in the mine, based on the detailed major elements, trace elements and gamma spectroscopy inspection of the rock types of deposit, the U, Th enrichment was undetectable. However, the U and Th content of about average terrestrial abundance of the great ore amount may be in the background of the increased radon concentration level. This Mn-carbonate ore deposit in spite of the low U content exhibit potential radon danger for miners, which can be eliminated with intensive air change only.

  18. Carbon Dynamics of Forest Floor and Stem in Black Spruce Forest Soils, Interior Alaska

    NASA Astrophysics Data System (ADS)

    Kim, Yongwon; Kim, Seong-Deog; Kim, Woongji

    2010-05-01

    Our automated open/close chamber system (AOCC) consists of eight chambers, a pump, CO2 gas analyzer, and a datalogger for CO2 data on the lichen, tussock, feather moss, and sphagnum moss of a black spruce forest, Interior Alaska, during the growing seasons of 2007 and 2008. During the observing periods of 2007 and 2008, the seasonal NEE was 0.127±0.049 and -0.039±0.025 mgCO2/m2/s in tussock regime, and 0.006±0.011 and 0.028±0.017 mgCO2/m2/s in sphagnum moss, respectively. Air temperature is a more significant regulator than soil temperature in determining the GPP and Re of forest floor vegetations. Air temperature explained 77-95% of the variability in GPP and Re of the floor vegetations. The contributions (%) of simulated seasonal GPP to the black spruce forest during non-growing periods (DOY 1-120 and 244-365) and during the growing period (DOY 121-243) of 2007 are 63-72%, 20-25%, and 8-18%, respectively. This indicates that the floor CO2 exchange, as well as the contribution of winter carbon emission, is a component of the regional carbon budget that cannot be neglected. As the result of simulated GPP and Re in tussock during 2007, tussocks are found to have on atmospheric CO2 release, similar to results of observation for 63-day of 2007. On the other hand of stem respiration rates of black spruce (Picea Mariana), the continuous measurement of stem respiration was conducted in black spruce stands of different ages (4.3 to 13.5 cm in DBH) in Interior Alaska during the growing seasons of 2007 and 2008, using a pump, CO2 analyzer, chambers, and data-logger. The averaged whole stem respiration rate is 0.011±0.005 mgCO2/m2/s (range 0.005±0.002 to 0.015±0.008 mgCO2/m2/s, CV 45%) in black spruce stands, indicating remarkably diurnal and seasonal variations of stem respiration among the stems during the growing season. It is found that metabolism exhibits 1.5-fold higher in the younger black spruce stand than in the older. Temperatures in the air and stem are

  19. Electrochemical evaluation of carbon nanotubes and carbon black for the cathode of Li-air batteries

    NASA Astrophysics Data System (ADS)

    Fuentes, Roderick E.; Colón-Mercado, Héctor R.; Fox, Elise B.

    2014-06-01

    Cyclic Voltammetry (CV) was used to screen carbon catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance as electrodes for the Li-air battery. Lithium bis(trifluoromethylsulfonyl)imide (LiTF2N) in tetraethylene glycol dimethyl ether (TEGDME) was used as the electrolyte during testing. The effect of manganese/manganese oxide addition on the performance of the carbons was compared to that of the bare carbons in a cycling study. From CV results, it was found that single walled carbon nanotubes (SWCNT) had the highest peak current density per gram for ORR and OER than the other types of carbon studied. The SWCNT ORR peak decreased 49% after 100 cycles and only 36% when manganese/manganese oxide was added. The high activity of SWCNT with manganese/manganese oxide spheres make it a desirable material to use as the cathode for Li-air batteries.

  20. Airborne intercomparison of vacuum ultraviolet fluorescence and tunable diode laser absorption measurements of tropospheric carbon monoxide

    NASA Astrophysics Data System (ADS)

    Holloway, John S.; Jakoubek, Roger O.; Parrish, David D.; Gerbig, Christoph; Volz-Thomas, Andreas; Schmitgen, Sandra; Fried, Alan; Wert, Brian; Henry, Bruce; Drummond, James R.

    2000-01-01

    During the fall 1997 North Atlantic Regional Experiment (NARE 97), two separate intercomparisons of aircraft-based carbon monoxide measurement instrumentation were conducted. On September 2, CO measurements were simultaneously made aboard the National Oceanic and Atmospheric Administration (NOAA) WP-3 by vacuum ultraviolet (VUV) fluorescence and by tunable diode laser absorption spectroscopy (TDLAS). On September 18, an intercomparison flight was conducted between two separate instruments, both employing the VUV fluorescence method, on the NOAA WP-3 and the U.K. Meteorological Office C-130 Hercules. The results indicate that both of the VUV fluorescence instruments and the TDLAS system are capable of measuring ambient CO accurately and precisely with no apparent interferences in 5 s. The accuracy of the measurements, based upon three independent calibration systems, is indicated by the agreement to within 11% with systematic offsets of less than 1 ppbv. In addition, one of the groups participated in the Measurement of Air Pollution From Satellite (MAPS) intercomparison [Novelli et al., 1998] with a different measurement technique but very similar calibration system, and agreed with the accepted analysis to within 5%. The precision of the measurements is indicated by the variability of the ratio of simultaneous measurements from the separate instruments. This variability is consistent with the estimated precisions of 1.5 ppbv and 2.2 ppbv for the 5 s average results of the C-130 and the WP-3 instruments, respectively, and indicates a precision of approximately 3.6% for the TDLAS instrument. The excellent agreement of the instruments in both intercomparisons demonstrates that significant interferences in the measurements are absent in air masses that ranged from 7 km in the midtroposphere to boundary layer conditions including subtropical marine air and continental outflow with embedded urban plumes. The intercomparison of the two VUV instruments that differed widely

  1. In vitro toxicity of carbon nanotubes, nano-graphite and carbon black, similar impacts of acid functionalization.

    PubMed

    Figarol, Agathe; Pourchez, Jérémie; Boudard, Delphine; Forest, Valérie; Akono, Céline; Tulliani, Jean-Marc; Lecompte, Jean-Pierre; Cottier, Michèle; Bernache-Assollant, Didier; Grosseau, Philippe

    2015-12-25

    Carbon nanotubes (CNT) and nano-graphite (NG) are graphene-based nanomaterials which share exceptional physicochemical properties, but whose health impacts are unfortunately still not well understood. On the other hand, carbon black (CB) is a conventional and widely studied material. The comparison of these three carbon-based nanomaterials is thus of great interest to improve our understanding of their toxicity. An acid functionalization was carried out on CNT, NG and CB so that, after a thorough characterization, their impacts on RAW 264.7 macrophages could be compared for a similar surface chemistry (15 to 120 μg·mL(-1) nanomaterials, 90-min to 24-h contact). Functionalized nanomaterials triggered a weak cytotoxicity similar to the pristine nanomaterials. Acid functionalization increased the pro-inflammatory response except for CB which did not trigger any TNF-α production before or after functionalization, and seemed to strongly decrease the oxidative stress. The toxicological impact of acid functionalization appeared thus to follow a similar trend whatever the carbon-based nanomaterial. At equivalent dose expressed in surface and equivalent surface chemistry, the toxicological responses from murine macrophages to NG were higher than for CNT and CB. It seemed to correspond to the hypothesis of a platelet and fiber paradigm. PMID:26381085

  2. End of the Little Ice Age in the Alps forced by industrial black carbon.

    PubMed

    Painter, Thomas H; Flanner, Mark G; Kaser, Georg; Marzeion, Ben; VanCuren, Richard A; Abdalati, Waleed

    2013-09-17

    Glaciers in the European Alps began to retreat abruptly from their mid-19th century maximum, marking what appeared to be the end of the Little Ice Age. Alpine temperature and precipitation records suggest that glaciers should instead have continued to grow until circa 1910. Radiative forcing by increasing deposition of industrial black carbon to snow may represent the driver of the abrupt glacier retreats in the Alps that began in the mid-19th century. Ice cores indicate that black carbon concentrations increased abruptly in the mid-19th century and largely continued to increase into the 20th century, consistent with known increases in black carbon emissions from the industrialization of Western Europe. Inferred annual surface radiative forcings increased stepwise to 13-17 W⋅m(-2) between 1850 and 1880, and to 9-22 W⋅m(-2) in the early 1900s, with snowmelt season (April/May/June) forcings reaching greater than 35 W⋅m(-2) by the early 1900s. These snowmelt season radiative forcings would have resulted in additional annual snow melting of as much as 0.9 m water equivalent across the melt season. Simulations of glacier mass balances with radiative forcing-equivalent changes in atmospheric temperatures result in conservative estimates of accumulating negative mass balances of magnitude -15 m water equivalent by 1900 and -30 m water equivalent by 1930, magnitudes and timing consistent with the observed retreat. These results suggest a possible physical explanation for the abrupt retreat of glaciers in the Alps in the mid-19th century that is consistent with existing temperature and precipitation records and reconstructions. PMID:24003138

  3. Intravascular Perfusion of Carbon Black Ink Allows Reliable Visualization of Cerebral Vessels

    PubMed Central

    Hasan, Mohammad R.; Herz, Josephine; Hermann, Dirk M.; Doeppner, Thorsten R.

    2013-01-01

    The anatomical structure of cerebral vessels is a key determinant for brain hemodynamics as well as the severity of injury following ischemic insults. The cerebral vasculature dynamically responds to various pathophysiological states and it exhibits considerable differences between strains and under conditions of genetic manipulations. Essentially, a reliable technique for intracranial vessel staining is essential in order to study the pathogenesis of ischemic stroke. Until recently, a set of different techniques has been employed to visualize the cerebral vasculature including injection of low viscosity resin, araldite F, gelatin mixed with various dyes1 (i.e. carmine red, India ink) or latex with2 or without3 carbon black. Perfusion of white latex compound through the ascending aorta has been first reported by Coyle and Jokelainen3. Maeda et al.2 have modified the protocol by adding carbon black ink to the latex compound for improved contrast visualization of the vessels after saline perfusion of the brain. However, inefficient perfusion and inadequate filling of the vessels are frequently experienced due to high viscosity of the latex compound4. Therefore, we have described a simple and cost-effective technique using a mixture of two commercially available carbon black inks (CB1 and CB2) to visualize the cerebral vasculature in a reproducible manner5. We have shown that perfusion with CB1+CB2 in mice results in staining of significantly smaller cerebral vessels at a higher density in comparison to latex perfusion5. Here, we describe our protocol to identify the anastomotic points between the anterior (ACA) and middle cerebral arteries (MCA) to study vessel variations in mice with different genetic backgrounds. Finally, we demonstrate the feasibility of our technique in a transient focal cerebral ischemia model in mice by combining CB1+CB2-mediated vessel staining with TTC staining in various degrees of ischemic injuries. PMID:23328838

  4. Global mountain snow and ice loss driven by dust and black carbon radiative forcing

    NASA Astrophysics Data System (ADS)

    Painter, T. H.

    2014-12-01

    Changes in mountain snow and glaciers have been our strongest indicators of the effects of changing climate. Earlier melt of snow and losses of glacier mass have perturbed regional water cycling, regional climate, and ecosystem dynamics, and contributed strongly to sea level rise. Recent studies however have revealed that in some regions, the reduction of albedo by light absorbing impurities in snow and ice such as dust and black carbon can be distinctly more powerful than regional warming at melting snow and ice. In the Rocky Mountains, dust deposition has increased 5 to 7 fold in the last 150 years, leading to ~3 weeks earlier loss of snow cover from forced melt. In absolute terms, in some years dust radiative forcing there can shorten snow cover duration by nearly two months. Remote sensing retrievals are beginning to reveal powerful dust and black carbon radiative forcing in the Hindu Kush through Himalaya. In light of recent ice cores that show pronounced increases in loading of dust and BC during the Anthropocene, these forcings may have contributed far more to glacier retreat than previously thought. For example, we have shown that the paradoxical end of the Little Ice Age in the European Alps beginning around 1850 (when glaciers began to retreat but temperatures continued to decline and precipitation was unchanged) very likely was driven by the massive increases in deposition to snow and ice of black carbon from industrialization in surrounding nations. A more robust understanding of changes in mountain snow and ice during the Anthropocene requires that we move past simplistic treatments (e.g. temperature-index modeling) to energy balance approaches that assess changes in the individual forcings such as the most powerful component for melt - net solar radiation. Remote sensing retrievals from imaging spectrometers and multispectral sensors are giving us more powerful insights into the time-space variation of snow and ice albedo.

  5. Effect of carbon black and/or elastomer on thermoplastic elastomer-based blends and composites

    NASA Astrophysics Data System (ADS)

    Yasar, M.; Bayram, G.; Celebi, H.

    2015-05-01

    It was aimed to investigate the effect of carbon black and/or elastomer on the electrical conductivity and mechanical properties of thermoplastic elastomer (TPE). Carbon black (CB) and ethylene-glycidyl methacrylate (E-GMA) were used as additives in the main matrix. The blends and composites were characterized in terms of their electrical conductivity and mechanical properties. CB concentration was varied as 0.5, 1, 3 and 5 wt.%. In order to modify the surface of CB, paraffinic oil and silane coupling agents were used. E-GMA was added to the matrix at 5, 10, 20, and 30 wt.% concentration. In order to prepare ternary composites, 5 wt.% of modified or unmodified carbon black and 10 wt.% of E-GMA were mixed with the TPE matrix. The tensile strength, impact strength and elongation at break values of TPE/CB composites decreased while elastic moduli and electrical conductivities increased with increasing CB concentration. It was observed that the surface modification of CB did not alter the tensile properties significantly. However, impact strength of the composites improved upon modification. For TPE/E-GMA blends, E-GMA addition enhanced the tensile strength and impact strength values of neat TPE. Nevertheless, elongation at break values began to decrease at 10 wt% and higher concentrations of E-GMA. It was observed that CB was more effective than the E-GMA on the mechanical properties of the ternary composites. The addition of 10 wt.% E-GMA increased the electrical resistivity and impact strength values of the ternary composites, as expected.

  6. Aerosol and black carbon properties during different seasons in eastern part of India

    NASA Astrophysics Data System (ADS)

    Kumari, Lipi

    Abstract Continuous and near-real-time measurements of the mass concentration of Aerosol Black Carbon (BC) were carried out July-2010 March-2011 using an Aethalometer (model AE-31 of Magee Scientific, USA). The principle of the Aethalometer is to measure the attenuation of a beam of light transmitted through a filter, while the filter is continuously collecting an aerosol sample. This measurement is made at successive regular intervals of a time base period. The BC mass concentration is estimated by measuring the change in the transmittance of a quartz filter tape, on to which the particles impinge. The instrument was operated at a time base of 5 min, round the clock with a flow rate of 4-liter min­¹, to study the impact of rainy season on black carbon concentrations over a typical urban environment namely Ranchi, India.BC concentrations were high during morning (0600 to 0900 h) and evening hours (1900 to 2300 h) compared to afternoon hours. During early morning hours, high values of BC are attributed to the turbulence set-in by the solar heating which breaks the night-time stable layer and aerosols in the nocturnal residual layer are mixed up with those near the surface. In a very clean air location it may be as low as 500 ng/m³ and in a very polluted location it may be as high as 20000 ng/m³. During the period from July-2010 to March 2011 the average monthly BC concentration varied between 1.1 to 8.1 µg/m³ and daily average value were found in the range of 1.0to 18 µg/m³. KEYWORDS: Black Carbon (BC), Aethalometer, Aerosol

  7. Associations between Prenatal Exposure to Black Carbon and Memory Domains in Urban Children: Modification by Sex and Prenatal Stress

    PubMed Central

    Cowell, Whitney J.; Bellinger, David C.; Coull, Brent A.; Gennings, Chris; Wright, Robert O.; Wright, Rosalind J.

    2015-01-01

    Background Whether fetal neurodevelopment is disrupted by traffic-related air pollution is uncertain. Animal studies suggest that chemical and non-chemical stressors interact to impact neurodevelopment, and that this association is further modified by sex. Objectives To examine associations between prenatal traffic-related black carbon exposure, prenatal stress, and sex with children’s memory and learning. Methods Analyses included N = 258 mother-child dyads enrolled in a Boston, Massachusetts pregnancy cohort. Black carbon exposure was estimated using a validated spatiotemporal land-use regression model. Prenatal stress was measured using the Crisis in Family Systems-Revised survey of negative life events. The Wide Range Assessment of Memory and Learning (WRAML2) was administered at age 6 years; outcomes included the General Memory Index and its component indices [Verbal, Visual, and Attention Concentration]. Relationships between black carbon and WRAML2 index scores were examined using multivariable-adjusted linear regression including effect modification by stress and sex. Results Mothers were primarily minorities (60% Hispanic, 26% Black); 67% had ≤12 years of education. The main effect for black carbon was not significant for any WRAML2 index; however, in stratified analyses, among boys with high exposure to prenatal stress, Attention Concentration Index scores were on average 9.5 points lower for those with high compared to low prenatal black carbon exposure (P3-way interaction = 0.04). Conclusion The associations between prenatal exposure to black carbon and stress with children’s memory scores were stronger in boys than in girls. Studies assessing complex interactions may more fully characterize health risks and, in particular, identify vulnerable subgroups. PMID:26544967

  8. An experimental study of the PTC properties of polymers with carbon black fillers

    NASA Astrophysics Data System (ADS)

    Lin, Jianlian

    The Positive Temperature Coefficient (PTC) phenomenon, first discovered by Harman in 1957, is defined as the sharp increase of the electrical resistivity of the material with temperature, especially at the Curie transition temperature. Polymeric PTC materials have been widely used since 1975 as self-regulating components, over current or over heat protectors, sensors, etc. In this project a detailed study of polymeric PTC materials has been carried out. Polymeric PTC materials consist of a non-conducting polymeric phase in which conductive particles, such as CB's, are added. Previously most of the studies of the polymer matrices of PTC materials were limited to single component semi-crystalline polymers, such as HDPE, LDPE, EVA etc. In this work, the PTC effects of carbon black filled binary polymer blends, such as LDPE/EPDM, HDPD/EPDM, HDPE/EVA, etc. are mainly studied. For the LDPE/EPDM/CB system, it is found that the PTC intensity of the blends after gamma-ray irradiation increases by almost 5 orders of magnitude compared with that of irradiated LDPE/CB compound. This increase in PTC intensity is due to the greater thermal expansion coefficient of the rubber (EPDM) phase. In addition, a comparison of E-beam and gamma-ray irradiation is made and the resulting effect on the PTC properties of LDPE/EPDM/CB blends is studied in detail. It is found that with higher dose of gamma-ray, the material undergoes significant radiation damage, while irradiation with E-beam prevents radiation damage due to shorter exposure time. The influence of using treated carbon blacks on the PTC/NTC effects of the composites is also studied. The polymer blends filled with oxidized carbon black display higher PTC intensity followed by a weaker NTC effect, which is due to stronger interactions between oxidized CB's & polymer. It is concluded that strong interactions between polymers and fillers suppress the NTC effect. Finally ESR analysis is used to study the interactions between the

  9. Corrosion behavior of modified nano carbon black/epoxy coating in accelerated conditions

    NASA Astrophysics Data System (ADS)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-03-01

    The electrochemical behavior and anticorrosion properties of modified carbon black (CB) nanoparticles in epoxy coatings were investigated in accelerated conditions. Nanoparticles of CB were modified by sodium dodecyl sulfate (SDS) as surfactant. Dispersion of nanoparticles into epoxy was confirmed by Transmission Electron Microscopy (TEM). The accelerated condition was prepared at 65 °C. CB nanoparticles improved corrosion resistance of the epoxy coating. The optimum concentration of CB in the epoxy coating was 0.75 wt%. Results showed that the CB hinder the corrosion due to its barrier properties. CB can decrease the diffusion coefficient of water in the coating with filling the micropores.

  10. Fractal morphology of black carbon aerosol enhances absorption in the thermal infrared wavelengths.

    PubMed

    Heinson, William R; Chakrabarty, Rajan K

    2016-02-15

    In this Letter, we numerically calculate the mass absorption cross sections (MACs) of black carbon fractal aggregates in the thermal infrared solar spectrum. Compared to equivalent-size spheres, the MAC values of aggregates show a percent enhancement of ≈150 and 400 at small and large length scales, respectively. The absorption properties of aggregates with size parameters >1 surprisingly continued to remain in the Rayleigh optics regime. We explain this phenomenon using the Maxwell-Garnett effective medium theory and the concept of phase shift parameter. PMID:26872194

  11. Enhancement of polymer photovoltaic performances by doping with modified carbon black nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi; He, Zhiqun; Xu, Min; Liang, Chunjun

    2015-08-01

    Low-cost carbon black nanoparticle (CBNP) was chemically modified by grafting with flexible alkyl groups. The modified CBNP (m-CBNP) forms a spider-like cluster with a considerably enhanced solubility, thereby enabling their uniform dispersal into a polymer matrix or active layers of bulk hetero-junction polymer photovoltaic cells, such as a blend of poly(3-hexylthiophene) and (6,6)-phenyl C61 butyric acid methyl ester. The performance of devices containing the m-CBNP was substantially improved. Charge carrier mobility enhancement was found to play a key role, leading to a 30 % improvement in the short-circuit current of the devices.

  12. Nonlinear scattering studies of carbon black suspensions using photoacoustic Z-scan technique

    NASA Astrophysics Data System (ADS)

    Kislyakov, Ivan M.; Yelleswarapu, Chandra S.

    2013-10-01

    Nonlinear scattering properties of carbon black suspensions (CBS) are studied using nanosecond photoacoustic (PA) and optical z-scan techniques. When the laser is operated in multi-pulse mode, no nonlinear behavior is observed in PAZ-scans. However, in the single-pulse mode, we observed the nonlinear scattering in both PAZ and optical z- scans. Our results are in agreement with the well-known bleaching effect in CBS and demonstrate the importance of pulse repetition frequency for studying nonlinear scattering using photoacoustics. The effective nonlinear extinction coefficients of CBS were determined, and we found that PAZ-scan data are more sensitive and offer information on higher nonlinearities.

  13. Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

    SciTech Connect

    Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

    1999-05-19

    The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage ("-OH") of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures.

  14. Black carbon concentration and deposition estimations in Finland by the regional aerosol-climate model REMO-HAM

    NASA Astrophysics Data System (ADS)

    Hienola, A. I.; Pietikäinen, J.-P.; Jacob, D.; Pozdun, R.; Petäjä, T.; Hyvärinen, A.-P.; Kerminen, V.-M.; Kulmala, M.; Laaksonen, A.

    2012-09-01

    The prediction skill of the regional aerosol-climate model REMO-HAM was assessed against the black carbon (BC) concentration measurements from five locations in Finland, with focus on Hyytiälä station for the year 2005. We examined to what extent the model is able to reproduce the measurements using several statistical tools: median comparison, overlap coefficient OVL (the common area under two probability distributions curves) and Z-score (a measure of standard deviation, shape and spread of the distributions). The results of the statistics showed that the model is biased low, suggesting either an excessive loss of black carbon in the model, or missing emissions. A further examination of the precipitation data from both measurements and model showed that there is no correlation between REMO's excessive precipitation and BC underestimation. This suggests that the excessive wet removal is not the main cause for the low black carbon concentration output. In addition, a comparison of wind directions in relation with high black carbon concentrations shows that REMO-HAM is able to predict the BC source directions relatively well. Cumulative black carbon deposition fluxes over Finland were estimated, including the deposition on snow.

  15. Interaction between carboxyl-functionalized carbon black nanoparticles and porous media

    NASA Astrophysics Data System (ADS)

    Kim, Song-Bae; Kang, Jin-Kyu; Yi, In-Geol

    2015-04-01

    Carbon nanomaterials, such as carbon nanotubes, fullerene, and graphene, have received considerable attention due to their unique physical and chemical characteristics, leading to mass production and widespread application in industrial, commercial, and environmental fields. During their life cycle from production to disposal, however, carbon nanomaterials are inevitably released into water and soil environments, which have resulted in concern about their health and environmental impacts. Carbon black is a nano-sized amorphous carbon powder that typically contains 90-99% elemental carbon. It can be produced from incomplete combustion of hydrocarbons in petroleum and coal. Carbon black is widely used in chemical and industrial products or applications such as ink pigments, coating plastics, the rubber industry, and composite reinforcements. Even though carbon black is strongly hydrophobic and tends to aggregate in water, it can be dispersed in aqueous media through surface functionalization or surfactant use. The aim of this study was therefore to investigate the transport behavior of carboxyl-functionalized carbon black nanoparticles (CBNPs) in porous media. Column experiments were performed for potassium chloride (KCl), a conservative tracer, and CBNPs under saturated flow conditions. Column experiments was conducted in duplicate using quartz sand, iron oxide-coated sand (IOCS), and aluminum oxide-coated sand (AOCS) to examine the effect of metal (Fe, Al) oxide presence on the transport of CBNPs. Breakthrough curves (BTCs) of CBNPs and chloride were obtained by monitoring effluent, and then mass recovery was quantified from these curves. Additionally, interaction energy profiles for CBNP-porous media were calculated using DLVO theory for sphere-plate geometry. The BTCs of chloride had relative peak concentrations ranging from 0.895 to 0.990. Transport parameters (pore-water velocity v, hydrodynamic dispersion coefficient D) obtained by the model fit from the

  16. Evaluation of an airborne triple-pulsed 2 μm IPDA lidar for simultaneous and independent atmospheric water vapor and carbon dioxide measurements.

    PubMed

    Refaat, Tamer F; Singh, Upendra N; Yu, Jirong; Petros, Mulugeta; Ismail, Syed; Kavaya, Michael J; Davis, Kenneth J

    2015-02-20

    Water vapor and carbon dioxide are the most dominant greenhouse gases directly contributing to the Earth's radiation budget and global warming. A performance evaluation of an airborne triple-pulsed integrated path differential absorption (IPDA) lidar system for simultaneous and independent monitoring of atmospheric water vapor and carbon dioxide column amounts is presented. This system leverages a state-of-the-art Ho:Tm:YLF triple-pulse laser transmitter operating at 2.05 μm wavelength. The transmitter provides wavelength tuning and locking capabilities for each pulse. The IPDA lidar system leverages a low risk and technologically mature receiver system based on InGaAs pin detectors. Measurement methodology and wavelength setting are discussed. The IPDA lidar return signals and error budget are analyzed for airborne operation on-board the NASA B-200. Results indicate that the IPDA lidar system is capable of measuring water vapor and carbon dioxide differential optical depth with 0.5% and 0.2% accuracy, respectively, from an altitude of 8 km to the surface and with 10 s averaging. Provided availability of meteorological data, in terms of temperature, pressure, and relative humidity vertical profiles, the differential optical depth conversion into weighted-average column dry-air volume-mixing ratio is also presented. PMID:25968204

  17. Effects of Floor Level and Building Type on Residential Levels of Outdoor and Indoor Polycyclic Aromatic Hydrocarbons, Black Carbon, and Particulate Matter in New York City

    PubMed Central

    Jung, Kyung Hwa; Bernabé, Kerlly; Moors, Kathleen; Yan, Beizhan; Chillrud, Steven N.; Whyatt, Robin; Camann, David; Kinney, Patrick L.; Perera, Frederica P.; Miller, Rachel L.

    2011-01-01

    Consideration of the relationship between residential floor level and concentration of traffic-related airborne pollutants may predict individual residential exposure among inner city dwellers more accurately. Our objective was to characterize the vertical gradient of residential levels of polycyclic aromatic hydrocarbons (PAH; dichotomized into Σ8PAHsemivolatile (MW 178–206), and Σ8PAHnonvolatile (MW 228–278), black carbon (BC), PM2.5 (particulate matter) by floor level (FL), season and building type. We hypothesize that PAH, BC and PM2.5 concentrations may decrease with higher FL and the vertical gradients of these compounds would be affected by heating season and building type. PAH, BC and PM2.5 were measured over a two-week period outdoor and indoor of the residences of a cohort of 5–6 year old children (n = 339) living in New York City’s Northern Manhattan and the Bronx. Airborne-pollutant levels were analyzed by three categorized FL groups (0–2nd, 3rd–5th, and 6th–32nd FL) and two building types (low-rise versus high-rise apartment building). Indoor Σ8PAHnonvolatile and BC levels declined with increasing FL. During the nonheating season, the median outdoor Σ8PAHnonvolatile, but not Σ8PAHsemivolatile, level at 6th–2nd FL was 1.5–2 times lower than levels measured at lower FL. Similarly, outdoor and indoor BC concentrations at 6th–32nd FL were significantly lower than those at lower FL only during the nonheating season (p < 0.05). In addition, living in a low-rise building was associated significantly with higher levels of Σ8PAHnonvolatile and BC. These results suggest that young inner city children may be exposed to varying levels of air pollutants depending on their FL, season, and building type. PMID:21886868

  18. Nanosized carbon black combined with Ni2O3 as "universal" catalysts for synergistically catalyzing carbonization of polyolefin wastes to synthesize carbon nanotubes and application for supercapacitors.

    PubMed

    Wen, Xin; Chen, Xuecheng; Tian, Nana; Gong, Jiang; Liu, Jie; Rümmeli, Mark H; Chu, Paul K; Mijiwska, Ewa; Tang, Tao

    2014-04-01

    The catalytic carbonization of polyolefin materials to synthesize carbon nanotubes (CNTs) is a promising strategy for the processing and recycling of plastic wastes, but this approach is generally limited due to the selectivity of catalysts and the difficulties in separating the polyolefin mixture. In this study, the influence of nanosized carbon black (CB) and Ni2O3 as a novel combined catalyst system on catalyzing carbonization of polypropylene (PP), polyethylene (PE), polystyrene (PS) and their blends was investigated. We showed that this combination was efficient to promote the carbonization of these polymers to produce CNTs with high yields and of good quality. Catalytic pyrolysis and model carbonization experiments indicated that the carbonization mechanism was attributed to the synergistic effect of the combined catalysts rendered by CB and Ni2O3: CB catalyzed the degradation of PP, PE, and PS to selectively produce more aromatic compounds, which were subsequently dehydrogenated and reassembled into CNTs via the catalytic action of CB together with Ni particles. Moreover, the performance of the synthesized CNTs as the electrode of supercapacitor was investigated. The supercapacitor displayed a high specific capacitance as compared to supercapacitors using commercial CNTs and CB. This difference was attributed to the relatively larger specific surface areas of our synthetic CNTs and their more oxygen-containing groups. PMID:24611910

  19. Comparing black carbon types in sequestering polybrominated diphenyl ethers (PBDEs) in sediments.

    PubMed

    Jia, Fang; Gan, Jay

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) are widely found in sediments, especially congeners from the penta-BDE formula. Due to their strong affinity for black carbon (BC), bioavailability of PBDEs may be decreased in BC-amended sediments. In this study, we used a matrix-SPME method to measure the freely dissolved concentration (Cfree) of PBDEs as a parameter of their potential bioavailability and evaluated the differences among biochar, charcoal, and activated carbon. Activated carbon displayed a substantially greater sequestration capacity than biochar or charcoal. At 1% amendment rate in sediment with low organic carbon (OC) content (0.12%), Cfree of six PBDEs was reduced by 47.5-78.0%, 47.3-77.5%, and 94.1-98.3% with biochar, charcoal, and activated carbon, respectively, while the sequestration was more limited in sediment with high OC content (0.87%). Therefore, it is important to consider the type and properties of the BC and the sediment in BC-based remediation or mitigation. PMID:24047549

  20. Comparing black carbon types in sequestering polybrominated diphenyl ethers (PBDEs) in sediments

    PubMed Central

    Jia, Fang; Gan, Jay

    2014-01-01

    Polybrominated diphenyl ethers (PBDEs) are widely found in sediments, especially congeners from the penta-BDE formula. Due to their strong affinity for black carbon (BC), bioavailability of PBDEs may be decreased in BC-amended sediments. In this study, we used a matrix-SPME method to measure the freely dissolved concentration (Cfree) of PBDEs as a parameter of their potential bioavailability and evaluated the differences among biochar, charcoal, and activated carbon. Activated carbon displayed a substantially greater sequestration capacity than biochar or charcoal. At 1% amendment rate in sediment with low organic carbon (OC) content (0.12%), Cfree of six PBDEs was reduced by 47.5–78.0%, 47.3–77.5%, and 94.1–98.3% with biochar, charcoal, and activated carbon, respectively, while the sequestration was more limited in sediment with high OC content (0.87%). Therefore, it is important to consider the type and properties of the BC and the sediment in BC-based remediation or mitigation. PMID:24047549

  1. Black carbon contribution to stabilised SOM in soil under slash and burn agriculture

    NASA Astrophysics Data System (ADS)

    Rumpel, C.; Chaplot, V.; Valentin, C.

    2008-12-01

    Black carbon (BC) produced during slash and burn agriculture on tropical soils may enhance the soils organic matter content and hence their biological properties. However, once deposited on the soil surface, BC may be subject to erosion and/or microbial decomposition and thus not be preserved on site. Up to now, few studies have been carried out to assess the contribution of BC to the soils stable carbon pool on sites under slash and burn agriculture. The aim of the study was to as