WorldWideScience

Sample records for black carbon concentrations

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

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    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.

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

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    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

  3. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

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    A. Massling

    2015-04-01

    Full Text Available Measurements of Black Carbon (BC in aerosols at the high Arctic field site Villum Research Station (VRS at Station Nord in North Greenland showed a seasonal variation in BC concentrations with a maximum in winter and spring at ground level. The data was 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. A correlation between BC and sulfate concentrations was observed over the years 2011 to 2013. 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. This process 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 BC measurements. 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 Hemispheric Model, DEHM. Good agreement between measured and modeled concentrations of both BC and sulfate was observed. The dominant source is found to be combustion of fossil fuel with biomass burning as a minor though significant source. During winter and spring the Arctic atmosphere is known to be impacted by long-range transport of BC and associated with the Arctic haze phenomenon.

  4. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

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    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

  5. A method for monitoring mass concentration of black carbon particulate matter using photothermal interferometry.

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    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.

  6. Spatio-temporal variations of black carbon concentrations in the Megacity Beijing.

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    Schleicher, Nina; Norra, Stefan; Fricker, Mathieu; Kaminski, Uwe; Chen, Yizhen; Chai, Fahe; Wang, Shulan; Yu, Yang; Cen, Kuang

    2013-11-01

    The spatial and temporal distribution and the flux of black carbon (BC) concentration in Beijing were continuously investigated over a two-year period at five sites to highlight the relative influence of contributing sources. The results demonstrate firstly that there is significant spatio-temporal variability of BC in Beijing. Highest concentrations occurred during winter primarily due to stagnant meteorological conditions, and seasonal BC sources, such as coal combustion for heating purposes. Biomass burning was identified as a minor seasonal source during the summer months. BC also varied spatially with higher concentrations in the SE of Beijing and lower concentrations in the NW, due to the differing emission intensity of various local BC sources such as traffic and industry. Frequently, overnight BC concentrations were higher due to specific meteorological conditions, such as the lower urban mixing layer height and various anthropogenic activities, such as exclusive night-time heavy duty vehicle traffic in the inner-city.

  7. Spatial variability of aerosol and black carbon concentrations in the troposphere of the Russian Arctic

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    Kozlov, Valerii S.; Panchenko, Mikhail V.; Paris, Jean D.; Nédéléc, Philippe; Chernov, Dmitry G.; Shmargunov, Vladimir P.

    2015-11-01

    A cycle of flights of the Optik TU-134 Flying Laboratory of IAO SB RAS over regions of Western Siberia and the Russian Arctic (55.0-74.8°N, 61.3-82.9°E) was carried out on October 15-17 of 2014 within the framework of the YAK-AEROSIB Russian—French Project. The mass concentrations of submicron aerosol and Black Carbon (BC) in the troposphere up to a height of 8.5 km were measured in the flights. The ranges of variability were 0.3-20 μg/m3 for the aerosol concentration and 0.02-1 μg/m3 for the BC concentration. In the subpolar latitudes of 71-74.8°N, the lower levels of aerosol (0.8-6 μg/m3) and BC (0.02-0.3 μg/m3) were observed. The comparison of the results of airborne sensing in 2008 and 2014 has shown that in the Western Subartic the aerosol and BC concentrations in the vertical profiles up to six times exceeded those observed in the Eastern Subarctic (0.3-1 μg/m3 and 10-50 ng/m3). The excess of the mean integral BC concentrations and the aerosol optical depth was, on average, 2-2.5 times (0.16 mg/m2; 0.02). In the region of the Kara Sea at heights of 0.5-2 and 4-6 km, the excess of the aerosol content in the western sector in comparison with the eastern one was, on average, 2 times, while for the black carbon the excess achieved 7 times at heights of 1-2 km (0.25- 0.035 μg/m3). The mean integral concentrations of aerosol and black carbon ˜ 1.3 times exceeded those in the clearer eastern region of the sea (0.31 mg/m2; 0.049). The obtained estimates indicate the decrease of the aerosol and BC concentrations in the subpolar latitudes of the Russian Federation from the west to the east.

  8. Assessing recent measurement techniques for quantifying black carbon concentration in snow

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    J. P. Schwarz

    2012-05-01

    Full Text Available We evaluate the performance of the Single Particle Soot Photometer (SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW in quantifying the concentration of refractory black carbon (BC in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60% than for atmospheric sampling (<30%. Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow tends to larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow and ice using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

  9. Concentrations of fine, ultrafine, and black carbon particles in auto-rickshaws in New Delhi, India

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    Apte, Joshua, S.; Kirchstetter, Thomas W.; Reich, Alexander, H.; Deshpande, Shyam J.; Kaushik, Geetanjali; Chel, Arvind; Marshall, Julian D.; Nazaroff, William W.

    2011-08-01

    Concentrations of air pollutants from vehicles are elevated along roadways, indicating that human exposure in transportation microenvironments may not be adequately characterized by centrally located monitors. We report results from ˜180 h of real-time measurements of fine particle and black carbon mass concentration (PM 2.5, BC) and ultrafine particle number concentration (PN) inside a common vehicle, the auto-rickshaw, in New Delhi, India. Measured exposure concentrations are much higher in this study (geometric mean for ˜60 trip-averaged concentrations: 190 μg m -3 PM 2.5, 42 μg m -3 BC, 280 × 10 3 particles cm -3; GSD ˜1.3 for all three pollutants) than reported for transportation microenvironments in other megacities. In-vehicle concentrations exceeded simultaneously measured ambient levels by 1.5× for PM 2.5, 3.6× for BC, and 8.4× for PN. Short-duration peak concentrations (averaging time: 10 s), attributable to exhaust plumes of nearby vehicles, were greater than 300 μg m -3 for PM 2.5, 85 μg m -3 for BC, and 650 × 10 3 particles cm -3 for PN. The incremental increase of within-vehicle concentration above ambient levels—which we attribute to in- and near-roadway emission sources—accounted for 30%, 68% and 86% of time-averaged in-vehicle PM 2.5, BC and PN concentrations, respectively. Based on these results, we estimate that one's exposure during a daily commute by auto-rickshaw in Delhi is as least as large as full-day exposures experienced by urban residents of many high-income countries. This study illuminates an environmental health concern that may be common in many populous, low-income cities.

  10. Estimating particulate black carbon concentrations using two offline light absorption methods applied to four types of filter media

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    Davy, Pamela M.; Tremper, Anja H.; Nicolosi, Eleonora M. G.; Quincey, Paul; Fuller, Gary W.

    2017-03-01

    Atmospheric particulate black carbon has been linked to adverse health outcomes. Additional black carbon measurements would aid a better understanding of population exposure in epidemiological studies as well as the success, or otherwise, of relevant abatement technologies and policies. Two light absorption measurement methods of particles collected on filters have been applied to four different types of filters to provide estimations of particulate black carbon concentrations. The ratio of transmittance (lnI0/I) to reflectance (lnR0/R) varied by filter type and ranged from close to 0.5 (as expected from simple theory) to 1.35 between the four filter types tested. The relationship between light absorption and black carbon, measured by the thermal EC(TOT) method, was nonlinear and differed between filter type and measurement method. This is particularly relevant to epidemiological studies that use light absorption as an exposure metric. An extensive archive of filters was used to derive loading factors and mass extinction coefficients for each filter type. Particulate black carbon time series were then calculated at locations where such measurements were not previously available. When applied to two roads in London, black carbon concentrations were found to have increased between 2011 and 2013, by 0.3 (CI: -0.1, 0.5) and 0.4 (CI: 0.1, 0.9) μg m-3 year-1, in contrast to the expectation from exhaust abatement policies. New opportunities using archived or bespoke filter collections for studies on the health effects of black carbon and the efficacy of abatement strategies are created.

  11. Large reductions in urban black carbon concentrations in the United States between 1965 and 2000

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    Kirchstetter, Thomas W.; Preble, Chelsea V.; Hadley, Odelle L.; Bond, Tami C.; Apte, Joshua S.

    2017-02-01

    Long-term pollutant concentration trends can be useful for evaluating air quality effects of emission controls and historical transitions in energy sources. We employed archival records of coefficient of haze (COH), a now-retired measure of light-absorbing particulate matter, to re-construct historical black carbon (BC) concentrations at urban locations in the United States (U.S.). The following relationship between COH and BC was determined by reinstating into service COH monitors beside aethalometers for two years in Vallejo and one year in San Jose, California: BC (μg m-3) = 6.7COH + 0.1, R2 = 0.9. Estimated BC concentrations in ten states stretching from the East to West Coast decreased markedly between 1965 and 1980: 5-fold in Illinois, Ohio, and Virginia, 4-fold in Missouri, and 2.5-fold in Pennsylvania. Over the period from the mid-1960s to the early 2000s, annual average BC concentrations in New Jersey and California decreased from 13 to 2 μg m-3 and 4 to 1 μg m-3, respectively, despite concurrent increases in fossil fuel consumption from 1.6 to 2.1 EJ (EJ = 1018 J) in New Jersey and 4.2 to 6.4 EJ in California. New Jersey's greater reliance on BC-producing heavy fuel oils and coal in the 1960s and early 1970s and subsequent transition to cleaner fuels explains why the decrease was larger in New Jersey than California. Patterns in seasonal and weekly BC concentrations and energy consumption trends together indicate that reducing wintertime emissions - namely substituting natural gas and electricity for heavy fuel oil in the residential sector - and decreasing emissions from diesel vehicles contributed to lower ambient BC concentrations. Over the period of study, declining concentrations of BC, a potent and short-lived climate warming pollutant, contrast increasing fossil fuel carbon dioxide (CO2) emissions in the U.S. Declining BC emissions may have had the benefit of mitigating some atmospheric warming driven by increased CO2 emissions with

  12. Observation of vertical variability of black carbon concentration in lower troposphere on campaigns in Poland

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    Chilinski, M. T.; Markowicz, K. M.; Markowicz, J.

    2016-07-01

    This study presents two methods for observation of black carbon (BC) vertical profiles in lower troposphere based on the micro-aethalometer AE-51. In the first method micro-aethalometer was carried by observer along trail on slope of mountain valley. Second method uses unmanned aerial vehicle as a platform for collecting data up to 1500 m above ground. Our study presents vertical profiles collected in and above Subcarphatian Wislok valley. Profiles measured on trial on slopes of Wislok valley, were collected during strong smog conditions during autumn/winter season, when BC concentration reached values above 60 μg/m3. The smog intensive layer is usually close to the surface (up to 100 m) as a results of surface inversion and the mountain breeze circulation, which during the night transports air pollution emitted from houses toward the valley's bottom. Usually the vertical profiles of BC concentration show significant reduction with the altitude, however, some multilayered structures are also observed during night time inversion conditions. It has found that smog condition can develop in clean air mass, and in those cases local pollution has significant impact on the columnar aerosol properties. During such conditions the aerosol optical depth shows diurnal cycle which is rather not observed in the long-term data. UAV flights in the lower troposphere were conducted during two sessions, one with clean polar air masses (BC concentration < 1 μg/m3) and second with moderate aerosol conditions (BC concentration 1-5 μg/m3). Profile of BC concentration shows stratification of absorbing aerosols in a shape of multi-layer structures similarly to the lidar/ceilometer signals.

  13. An analysis of continuous black carbon concentrations in proximity to an airport and major roadways

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    Dodson, Robin E.; Andres Houseman, E.; Morin, Barbara; Levy, Jonathan I.

    Black carbon (BC), a constituent of particulate matter, is emitted from multiple combustion sources, complicating determination of contributions from individual sources or source categories from monitoring data. In close proximity to an airport, this may include aircraft emissions, other emissions on the airport grounds, and nearby major roadways, and it would be valuable to determine the factors most strongly related to measured BC concentrations. In this study, continuous BC concentrations were measured at five monitoring sites in proximity to a small regional airport in Warwick, Rhode Island from July 2005 to August 2006. Regression was used to model the relative contributions of aircraft and related sources, using real-time flight activity (departures and arrivals) and meteorological data, including mixing height, wind speed and direction. The latter two were included as a nonparametric smooth spatial term using thin-plate splines applied to wind velocity vectors and fit in a linear mixed model framework. Standard errors were computed using a moving-block bootstrap to account for temporal autocorrelation. Results suggest significant positive associations between hourly departures and arrivals at the airport and BC concentrations within the community, with departures having a more substantial impact. Generalized Additive Models for wind speed and direction were consistent with significant contributions from the airport, major highway, and multiple local roads. Additionally, inverse mixing height, temperature, precipitation, and at one location relative humidity, were associated with BC concentrations. Median contribution estimates indicate that aircraft departures and arrivals (and other sources coincident in space and time) contribute to approximately 24-28% of the BC concentrations at the monitoring sites in the community. Our analysis demonstrated that a regression-based approach with detailed meteorological and source characterization can provide insights

  14. Comparison of black carbon (BC) aerosols in two urban areas - concentrations and size distributions

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    Hitzenberger, R.; Tohno, S.

    In this study, the BC aerosol measured at two very different urban sites is compared in terms of concentration, seasonal variation, and size distribution. During a 14 month study, one impactor sample was performed each month on a day with typical meteorological conditions. One (Vienna) or three (Uji) filter samples were obtained during the sampling time of the impactors. BC concentration in both the filter and impactor samples was analyzed with an optical technique (integrating sphere technique), where a calibration curve obtained from commercial carbon black is used to convert the optical signal to BC mass. Gravimetric mass concentration was measured at both sites. The gravimetric mass size distribution was measured only in Vienna. At both sites, the yearly average of the BC concentration on the sampling days was around 5 μg m -3. In Vienna, some seasonal trend with high concentrations during the cold season was observed, while in Uji, no pronounced seasonal trend was found. The BC size distribution in Uji was distinctly bimodal in the submicron size range. Log-normal distributions were fitted through the impactor data. The average BC mass median diameters (MMD) of the two submicron modes were 0.15 and 0.39 μm. Each mode contained about the same amount of BC mass. In Vienna only one submicron BC mode (average MMD 0.3 μm) was found because of the low size resolution of the impactor. An analysis of humidity effects on the MMDs of BC (both sites) and gravimetric mass (Vienna only) indicates that the Vienna aerosol is partly mixed internally with respect to BC, while the Uji aerosol seems to be externally mixed.

  15. Parametric uncertainties in global model simulations of black carbon column mass concentration

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    Pearce, Hana; Lee, Lindsay; Reddington, Carly; Carslaw, Ken; Mann, Graham

    2016-04-01

    Previous studies have deduced that the annual mean direct radiative forcing from black carbon (BC) aerosol may regionally be up to 5 W m-2 larger than expected due to underestimation of global atmospheric BC absorption in models. We have identified the magnitude and important sources of parametric uncertainty in simulations of BC column mass concentration from a global aerosol microphysics model (GLOMAP-Mode). A variance-based uncertainty analysis of 28 parameters has been performed, based on statistical emulators trained on model output from GLOMAP-Mode. This is the largest number of uncertain model parameters to be considered in a BC uncertainty analysis to date and covers primary aerosol emissions, microphysical processes and structural parameters related to the aerosol size distribution. We will present several recommendations for further research to improve the fidelity of simulated BC. In brief, we find that the standard deviation around the simulated mean annual BC column mass concentration varies globally between 2.5 x 10-9 g cm-2 in remote marine regions and 1.25 x 10-6 g cm-2 near emission sources due to parameter uncertainty Between 60 and 90% of the variance over source regions is due to uncertainty associated with primary BC emission fluxes, including biomass burning, fossil fuel and biofuel emissions. While the contributions to BC column uncertainty from microphysical processes, for example those related to dry and wet deposition, are increased over remote regions, we find that emissions still make an important contribution in these areas. It is likely, however, that the importance of structural model error, i.e. differences between models, is greater than parametric uncertainty. We have extended our analysis to emulate vertical BC profiles at several locations in the mid-Pacific Ocean and identify the parameters contributing to uncertainty in the vertical distribution of black carbon at these locations. We will present preliminary comparisons of

  16. Black carbon concentration and deposition estimations in Finland by the regional aerosol–climate model REMO-HAM

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    A. I. Hienola

    2013-04-01

    Full Text Available 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. The local and regional emissions of BC have a significant contribution, and the model tendency to flatten the observed BC is most likely dominated by the lack of domestic burning of biofuel in the emission inventories. 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 of 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.

  17. Characterization of long-term and seasonal variations of black carbon (BC concentrations at Neumayer, Antarctica

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    R. Weller

    2012-09-01

    Full Text Available Continuous black carbon (BC observations were conducted from 1999 through 2009 by an Aethalometer (AE10 and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP at Neumayer Station (NM under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng m−3 compared to the AE10 results (1.6 ± 2.1 ng m−3. Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of ω550 = 0.992 ± 0.0090 (median: 0.994 at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

  18. Characterization of long-term and seasonal variations of black carbon (BC) concentrations at Neumayer, Antarctica

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    Weller, R.; Minikin, A.; Petzold, A.; Wagenbach, D.; König-Langlo, G.

    2013-02-01

    Continuous black carbon (BC) observations were conducted from 1999 through 2009 by an Aethalometer (AE10) and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP) at Neumayer Station (NM) under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng m-3) compared to the AE10 results (1.6 ± 2.1 ng m-3). Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of ω550 = 0.992 ± 0.0090 (median: 0.994) at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

  19. Characterization of long-term and seasonal variations of black carbon (BC concentrations at Neumayer, Antarctica

    Directory of Open Access Journals (Sweden)

    R. Weller

    2013-02-01

    Full Text Available Continuous black carbon (BC observations were conducted from 1999 through 2009 by an Aethalometer (AE10 and from 2006 through 2011 by a Multi-Angle Absorption Photometer (MAAP at Neumayer Station (NM under stringent contamination control. Considering the respective observation period, BC concentrations measured by the MAAP were somewhat higher (median ± standard deviation: 2.1 ± 2.0 ng m−3 compared to the AE10 results (1.6 ± 2.1 ng m−3. Neither for the AE10 nor for the MAAP data set a significant long-term trend could be detected. Consistently a pronounced seasonality was observed with both instruments showing a primary annual maximum between October and November and a minimum in April with a maximum/minimum ratio of 4.5/1.6 = 3.8 and 2.7/0.64 = 4.2 for the MAAP and AE10 data, respectively. Occasionally a secondary summer maximum in January/February was visible. With the aim to assess the impact of BC on optical properties of the aerosol at NM, we evaluated the BC data along with particle scattering coefficients measured by an integrating nephelometer. We found the mean single scattering albedo of ω550 = 0.992 ± 0.0090 (median: 0.994 at a wavelength of 550 nm with a range of values from 0.95 to 1.0.

  20. Source sector and region contributions to concentration and direct radiative forcing of black carbon in China

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    Li, Ke; Liao, Hong; Mao, Yuhao; Ridley, David A.

    2016-01-01

    We quantify the contributions from five domestic emission sectors (residential, industry, transportation, energy, and biomass burning) and emissions outside of China (non-China) to concentration and direct radiative forcing (DRF) of black carbon (BC) in China for year 2010 using a nested-grid version of the global chemical transport model (GEOS-Chem) coupled with a radiative transfer model. The Hemispheric Transport of Air Pollution (HTAP) anthropogenic emissions of BC for year 2010 are used in this study. Simulated surface-layer BC concentrations in China have strong seasonal variations, which exceed 9 μg m-3 in winter and are about 1-5 μg m-3 in summer in the North China Plain and the Sichuan Basin. Residential sector is simulated to have the largest contribution to surface BC concentrations, by 5-7 μg m-3 in winter and by 1-3 μg m-3 in summer, reflecting the large emissions from winter heating and the enhanced wet deposition during summer monsoon. The contribution from industry sector is the second largest and shows relatively small seasonal variations; the emissions from industry sector contribute 1-3 μg m-3 to BC concentrations in the North China Plain and the Sichuan Basin. The contribution from transportation sector is the third largest, followed by that from biomass burning and energy sectors. The non-China emissions mainly influence the surface-layer concentrations of BC in western China; about 70% of surface-layer BC concentration in the Tibet Plateau is attributed to transboundary transport. Averaged over all of China, the all-sky DRF of BC at the top of the atmosphere (TOA) is simulated to be 1.22 W m-2. Sensitivity simulations show that the TOA BC direct radiative forcings from the five domestic emission sectors of residential, industry, energy, transportation, biomass burning, and non-China emissions are 0.44, 0.27, 0.01, 0.12, 0.04, and 0.30 W m-2, respectively. The domestic and non-China emissions contribute 75% and 25% to BC DRF in China

  1. Modeling Study of the Contribution of Wildfires to Ambient Black Carbon Concentrations

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    Chung, S. H.; Gonzalez-Abraham, R.; Lamb, B. K.; Larkin, N. K.; Strand, T.; O'Neill, S.

    2013-12-01

    Wildland fires are a major source of particulate emissions, including black carbon (BC). In combination with other emissions, these BC and particulate emissions can directly lead to air quality degradation, both locally and more regionally. BC and other particulate matter (PM) can also affect climate in various ways, including by scattering and absorbing radiation, modifying cloud formation and properties, and changing snow albedo. BC emissions reduction is a potential strategy for mitigating global warming because it is emitted in large quantities and has a relatively short lifetime in the atmosphere in comparison to long-live greenhouse gases. Due to the highly variable nature of wildland fires, both in terms of fire occurrences on the landscape and the high spatial and temporal variability of fuels, consumption, and emissions, the impact of wildfire emissions varies significantly over the period of the wildfire season as well as inter-annually. In the U.S., while anthropogenic emissions are projected to decrease, as the climate warms wildfire activity is predicted to increase along with the contribution of fire emissions. Thus, a robust analysis of the effects of BC from fire emissions on air quality and climate necessitates a comprehensive, multi-scale study of all fire-related pollutants and other emission sources spanning multiple years of fire data and weather conditions. In this study we apply the WRF-BlueSky-SMOKE-CMAQ regional air-quality modeling system for multi-year (1997-2005) summertime simulations to evaluate the contribution of fire emissions to atmospheric BC and total PM2.5 concentrations. Historical fire records from the Bureau of Land Management are used by the BlueSky framework to calculate fire emissions. Plume rise is calculated by the SMOKE emission processor, taking into account meteorology from the WRF model. These emissions are combined with anthropogenic emissions from the NEI 2002 and biogenic emissions from the MEGAN model. CMAQ is

  2. Black carbon concentrations across the tropical Atlantic boundary layer using three methods

    Science.gov (United States)

    Pohl, K.; Lohmann, R.; Cantwell, M.; Herckes, P.

    2012-12-01

    24 particulate black carbon (BC) samples were quantified using three methods: a chemo-thermal oxidation at 375°C (CTO-375), a thermal optical transition method (Sunset Method), and pyrene fluorescence loss (PFL). BC samples were taken using a high-volume air sampler aboard the R/V Endeavor during the summer of 2010 in the Equatorial Atlantic Ocean in order to sample the aeolian "hotspot" plume of aerosols that extend from the African continent. Models have shown that annual elemental carbon (EC) deposition fluxes in this area could be as high as 25μg cm-2 a-1, which may be a significant contribution to the overall carbon budget as well as climate forcing simulations. Expected BC concentrations for this area, based on a global BC inventory using the MOGUNTIA global transport model, range between 0.01-1μg/m3 depending on season. The CTO-375 processed samples were run on an IRMS to get the total organic carbon (TOC), BC concentrations, and δ13C isotope ratios. BC was detected in every sample and concentrations ranged between 0.16-9.97μg/m3. BC concentrations were highest off the coast of the US and Caribbean islands but were lower (0.16-0.26μg/m3) in the African plume sampled between 1-5°N and 21-29°W. BC comprised between 13-81% of the TOC pool and δ13C isotopes between the TOC and BC for each sample differed by no more than 3‰. The TOC and BC pools average was -28.9‰ and -28.1‰ respectively, suggesting a C4 plant origin. A different isotope trend was evident for samples 16-19 (African plume). Their δ13C average was -23.1‰ for TOC, suggesting a mostly marine origin of the organic carbon or a mix of marine with C3 and C4 plants. This supports the observed lower BC/TOC ratio in these samples (13-50%). EC concentrations determined by the Sunset Method ranged between 0-0.32μg/m3, with EC being detected in only 8 of the 24 samples. In general, EC was found above the detection limit near the United States coastline or in the "hotspot" plume off Africa

  3. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    OpenAIRE

    2014-01-01

    Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emission plume of biomass and agricultural burning products. Atmospheric particulate matter samples across the tropical Atlantic boundary layer were collected in the summer of 2010 during the southern he...

  4. Cluster analysis of particulate matter (PM10) and black carbon (BC) concentrations

    Science.gov (United States)

    Žibert, Janez; Pražnikar, Jure

    2012-09-01

    The monitoring of air-pollution constituents like particulate matter (PM10) and black carbon (BC) can provide information about air quality and the dynamics of emissions. Air quality depends on natural and anthropogenic sources of emissions as well as the weather conditions. For a one-year period the diurnal concentrations of PM10 and BC in the Port of Koper were analysed by clustering days into similar groups according to the similarity of the BC and PM10 hourly derived day-profiles without any prior assumptions about working and non-working days, weather conditions or hot and cold seasons. The analysis was performed by using k-means clustering with the squared Euclidean distance as the similarity measure. The analysis showed that 10 clusters in the BC case produced 3 clusters with just one member day and 7 clusters that encompasses more than one day with similar BC profiles. Similar results were found in the PM10 case, where one cluster has a single-member day, while 7 clusters contain several member days. The clustering analysis revealed that the clusters with less pronounced bimodal patterns and low hourly and average daily concentrations for both types of measurements include the most days in the one-year analysis. A typical day profile of the BC measurements includes a bimodal pattern with morning and evening peaks, while the PM10 measurements reveal a less pronounced bimodality. There are also clusters with single-peak day-profiles. The BC data in such cases exhibit morning peaks, while the PM10 data consist of noon or afternoon single peaks. Single pronounced peaks can be explained by appropriate cluster wind speed profiles. The analysis also revealed some special day-profiles. The BC cluster with a high midnight peak at 30/04/2010 and the PM10 cluster with the highest observed concentration of PM10 at 01/05/2010 (208.0 μg m-3) coincide with 1 May, which is a national holiday in Slovenia and has very strong tradition of bonfire parties. The clustering of

  5. Quantitative Analysis of Major Factors Affecting Black Carbon Transport and Concentrations in the Unique Atmospheric Structures of Urban Environment

    Science.gov (United States)

    Liang, Marissa Shuang

    Black carbon (BC) from vehicular emission in transportation is a principal component of particulate matters ≤ 2.5 mum (PM2.5). PM2.5 and other diesel emission pollutants (e.g., NOx) are regulated by the Clean Air Act (CAA) according to the National Ambient Air Quality standards (NAAQS). This doctoral dissertation details a study on transport behaviors of black carbon and PM2.5 from transportation routes, their relations with the atmospheric structure of an urban formation, and their relations with the use of biodiesel fuels. The results have implications to near-road risk assessment and to the development of sustainable transportation solutions in urban centers. The first part of study quantified near-roadside black carbon transport as a function of particulate matter (PM) size and composition, as well as microclimatic variables (temperature and wind fields) at the interstate highway I-75 in northern Cincinnati, Ohio. Among variables examined, wind speed and direction significantly affect the roadside transport of black carbon and hence its effective emission factor. Observed non-Gaussian dispersion occurred during low wind and for wind directions at acute angles or upwind to the receptors, mostly occurring in the morning hours. Meandering of air pollutant mass under thermal inversion is likely the driving force. In contrary, Gaussian distribution predominated in daytime of strong downwinds. The roles of urban atmospheric structure, wind fields, and the urban heat island (UHI) effects were further examined on pollutant dispersion and transport. Spatiotemporal variations of traffic flow, atmospheric structure, ambient temperature and PM2.5 concentration data from 14 EPA-certified NAAQS monitoring stations, were analyzed in relation to land-use in the Cincinnati metropolitan area. The results show a decade-long UHI effects with higher interior temperature than that in exurban, and a prominent nocturnal thermal inversion frequent in urban boundary layer. The

  6. Characteristics of black carbon concentration at a metropolitan city located near land-ocean boundary in Eastern India

    Science.gov (United States)

    Talukdar, Shamitaksha; Jana, Soumyajyoti; Maitra, Animesh; Gogoi, Mukunda M.

    2015-02-01

    Near surface aerosol black carbon (BC) concentration data were collected using a seven channel Aethalometer (AE31) during June 2012-May 2013 in Kolkata (22° 34‧E, 88° 22‧N), a metropolitan city located near the land-ocean boundary in Eastern India. BC concentration shows a prominent seasonal and diurnal variation associated with the meteorological parameters. The mean BC concentration varied from 5 μg/m3 to 27 μg/m3 seasonally. The variation of BC mass concentration and its significant association with atmospheric parameters such as temperature profile, relative humidity and wind speed have been studied. Moreover, the influence of the transported air masses on BC concentration at different seasons has also been discussed. An estimation of Angstrom exponent discloses that fossil fuel combustion is a major source of BC at this location.

  7. Variability of levels of PM, black carbon and particle number concentration in selected European cities

    Directory of Open Access Journals (Sweden)

    C. Reche

    2011-03-01

    Full Text Available In many large cities of Europe standard air quality limit values of particulate matter (PM are exceeded. Emissions from road traffic and biomass burning are frequently reported to be the major causes. As a consequence of these exceedances a large number of air quality plans, most of them focusing on traffic emissions reductions, have been implemented in the last decade. In spite of this implementation, a number of cities did not record a decrease of PM levels. Thus, is the efficiency of air quality plans overestimated? Or do we need a more specific metric to evaluate the impact of the above emissions on the levels of urban aerosols?

    This study shows the results of the interpretation of the 2009 variability of levels of PM, black carbon (BC, aerosol number concentration (N and a number of gaseous pollutants in seven selected urban areas covering road traffic, urban background, urban-industrial, and urban-shipping environments from southern, central and northern Europe.

    The results showed that variations of PM and N levels do not always reflect the variation of the impact of road traffic emissions on urban aerosols. However, BC levels vary proportionally with those of traffic related gaseous pollutants, such as CO, NO2 and NO. Due to this high correlation, one may suppose that monitoring the levels of these gaseous pollutants would be enough to extrapolate exposure to traffic-derived BC levels. However, the BC/CO, BC/NO2 and BC/NO ratios vary widely among the cities studied, as a function of distance to traffic emissions, vehicle fleet composition and the influence of other emission sources such as biomass burning. Thus, levels of BC should be measured at air quality monitoring sites.

    During traffic rush hours, a narrow variation in the N/BC ratio was evidenced, but a wide variation of this ratio was determined for the noon period. Although in central and northern Europe N and BC levels tend to vary

  8. Aerosol mass and black carbon concentrations, two year-round observations at NCO-P (5079 m, Southern Himalayas

    Directory of Open Access Journals (Sweden)

    A. Marinoni

    2010-03-01

    Full Text Available Aerosol mass and the absorbing fraction are important variables, needed to constrain the role of atmospheric particles in the Earth radiation budget, both directly and indirectly through CCN activation. In particular, their monitoring in remote areas and mountain sites is essential for determining source regions, elucidating the mechanisms of long range transport of anthropogenic pollutants, and validating regional and global models. Since March 2006, aerosol mass and black carbon concentration have been monitored at the Nepal Climate Observatory-Pyramid, a permanent high-altitude research station located in the Khumbu valley at 5079 m a.s.l. below Mt. Everest. The first two-year averages of PM1 and PM1-10 mass were 1.94 μg m−3 and 1.88 μg m−3, with standard deviations of 3.90 μg m−3 and 4.45 μg m−3, respectively, while the black carbon concentration average is 160.5 ng m−3, with a standard deviation of 296.1 ng m−3. Both aerosol mass and black carbon show well defined annual cycles, with a maximum during the pre-monsoon season and a minimum during the monsoon. They also display a typical diurnal cycle during all the seasons, with the lowest particle concentration recorded during the night, and a considerable increase during the afternoon, revealing the major role played by thermal winds in influencing the behaviour of atmospheric compounds over the high Himalayas. The aerosol concentration is subject to high variability: in fact, as well as frequent "background conditions" (55% of the time when BC concentrations are mainly below 100 ng m−3, concentrations up to 5 μg m−3 are reached during some episodes (a few days every year in the pre-monsoon seasons. The variability of PM and BC is the result of both short-term changes due to thermal wind development in the valley, and long-range transport/synoptic circulation. At

  9. Aerosol mass and black carbon concentrations, a two year record at NCO-P (5079 m, Southern Himalayas

    Directory of Open Access Journals (Sweden)

    A. Marinoni

    2010-09-01

    Full Text Available Aerosol mass and the absorbing fraction are important variables, needed to constrain the role of atmospheric particles in the Earth radiation budget, both directly and indirectly through CCN activation. In particular, their monitoring in remote areas and mountain sites is essential for determining source regions, elucidating the mechanisms of long range transport of anthropogenic pollutants, and validating regional and global models. Since March 2006, aerosol mass and black carbon concentration have been monitored at the Nepal Climate Observatory-Pyramid, a permanent high-altitude research station located in the Khumbu valley at 5079 m a.s.l. below Mt. Everest. The first two-year averages of PM1 and PM1−10 mass were 1.94 μg m−3 and 1.88 μg m−3, with standard deviations of 3.90 μg m−3 and 4.45 μg m−3, respectively, while the black carbon concentration average is 160.5 ng m−3, with a standard deviation of 296.1 ng m−3. Both aerosol mass and black carbon show well defined annual cycles, with a maximum during the pre-monsoon season and a minimum during the monsoon. They also display a typical diurnal cycle during all the seasons, with the lowest particle concentration recorded during the night, and a considerable increase during the afternoon, revealing the major role played by thermal winds in influencing the behaviour of atmospheric compounds over the high Himalayas. The aerosol concentration is subject to high variability: in fact, as well as frequent "background conditions" (55% of the time when BC concentrations are mainly below 100 ng m−3, concentrations up to 5 μg m−3 are reached during some episodes (a few days every year in the pre-monsoon seasons. The variability of PM and BC is the result of both short-term changes due to thermal wind development in the valley, and long-range transport/synoptic circulation

  10. Characteristics of High Time-Resolved Concentrations of Particulate Inorganic Ions and Black Carbon Downwind of Seoul, Korea

    Science.gov (United States)

    Lee, Y.; Choi, Y.; Kim, C.; Ghim, Y.

    2012-12-01

    Concentrations of inorganic ions and black carbon (BC) in PM2.5 were continuously measured using PILS (particle-into-liquid sampler, ADI 2081, Applikon) and MAAP (Multiangle Absorption Photometer, Model 5012, Thermo), respectively, for three and half months from mid-February to May, at intervals of 20-30 minutes. The measurements were made at the Global Campus of Hankuk University of Foreign Studies, about 35 km southeast of downtown Seoul, the general area of which is affected by prevailing northwesterlies. The site is considered to be an ideal place for exploring transport of air pollutants and formation of secondary ions by photochemical reactions since there are no major emission sources nearby except a 4-lane road running about 1.4 km to the west. Analyses were made by two stages. In the first stage, typical types of diurnal variations in inorganic ions and BC concentrations were identified using cluster analysis. Diurnal variations in concentrations of each cluster were compared with the mean diurnal variations during the measurement period. Factors causing the differences in diurnal variations were discussed by cluster and by species. In the second stage, high and low concentration episodes were determined based on three-day moving averages of the sum of concentrations of particulate inorganic ions and BC. Mean concentrations and compositions in each episode were compared with those during the measurement period.

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

    Science.gov (United States)

    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.

  12. Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies

    Science.gov (United States)

    Pohl, K.; Cantwell, M.; Herckes, P.; Lohmann, R.

    2013-11-01

    Black carbon (BC) is the highly carbonaceous byproduct of biomass burning and fossil fuel combustion with a composition ranging from thermally stable soot to less recalcitrant charcoal. Atmospheric particulate matter samples across the tropical Atlantic Ocean were quantified for BC using four different methods: chemothermal oxidation at 375 °C (CTO-375), pyrene fluorescence loss, thermal optical transmittance, and optical transmission attenuation. The highest BC concentrations were detected in the Caribbean Sea and off the African coast, with a regional average of 0.6 μg m-3 for both. The lowest average concentrations were measured off the coast of South America at 0.2 to 0.3 μg m-3. The thermally-based CTO-375 method generally detected lower BC concentrations than the other three methods. The ratio of soot-like BC, as defined by the CTO-375 method, relative to the broader BC combustion continuum, as defined by the pyrene fluorescence loss, was <1 for all regions except for the Caribbean, supporting that charcoal was an important fraction of the aerosol BC. Regions impacted by biomass burning emissions should utilize multiple methods to better apportion the BC concentrations and sources.

  13. Black Carbon Concentrations and Diesel Vehicle Emission Factors Derived from Coefficient of Haze Measurements in California: 1967-2003

    Energy Technology Data Exchange (ETDEWEB)

    Tast, CynthiaL; Kirchstetter, Thomas W.; Aguiar, Jeffery; Tonse, Shaheen; Novakov, T.; Fairley, David

    2007-11-09

    We have derived ambient black carbon (BC) concentrations and estimated emission factors for on-road diesel vehicles from archived Coefficient of Haze (COH) data that was routinely collected beginning in 1967 at 11 locations in the San Francisco Bay Area. COH values are a measure of the attenuation of light by particles collected on a white filter, and available data indicate they are proportional to BC concentrations measured using the conventional aethalometer. Monthly averaged BC concentrations are up to five times greater in winter than summer, and, consequently, so is the population?s exposure to BC. The seasonal cycle in BC concentrations is similar for all Bay Area sites, most likely due to area-wide decreased pollutant dispersion during wintertime. A strong weekly cycle is also evident, with weekend concentrations significantly lower than weekday concentrations, consistent with decreased diesel traffic volume on weekends. The weekly cycle suggests that, in the Bay Area, diesel vehicle emissions are the dominant source of BC aerosol. Despite the continuous increase in diesel fuel consumption in California, annual Bay Area average BC concentrations decreased by a factor of ~;;3 from the late 1960s to the early 2000s. Based on estimated annual BC concentrations, on-road diesel fuel consumption, and recent measurements of on-road diesel vehicle BC emissions, diesel BC emission factors decreased by an order of magnitude over the study period. Reductions in the BC emission factor reflect improved engine technology, emission controls and changes in diesel fuel composition. A new BC monitoring network is needed to continue tracking ambient BC trends because the network of COH monitors has recently been retired.

  14. Black Carbon Concentrations and Diesel Vehicle Emission FactorsDerived from Coefficient of Haze Measurements in California:1967-2003

    Energy Technology Data Exchange (ETDEWEB)

    Kirchstetter, Thomas W.; Aguiar, Jeffery; Tonse, Shaheen; Novakov, T.

    2007-10-01

    We have derived ambient black carbon (BC) concentrations and estimated emission factors for on-road diesel vehicles from archived Coefficient of Haze (COH) data that was routinely collected beginning in 1967 at 11 locations in the San Francisco Bay Area. COH values are a measure of the attenuation of light by particles collected on a white filter, and available data indicate they are proportional to BC concentrations measured using the conventional aethalometer. Monthly averaged BC concentrations are up to five times greater in winter than summer, and, consequently, so is the population's exposure to BC. The seasonal cycle in BC concentrations is similar for all Bay Area sites, most likely due to area-wide decreased pollutant dispersion during wintertime. A strong weekly cycle is also evident, with weekend concentrations significantly lower than weekday concentrations, consistent with decreased diesel traffic volume on weekends. The weekly cycle suggests that, in the Bay Area, diesel vehicle emissions are the dominant source of BC aerosol. Despite the continuous increase in diesel fuel consumption in California, annual Bay Area average BC concentrations decreased by a factor of {approx}3 from the late 1960s to the early 2000s. Based on estimated annual BC concentrations, on-road diesel fuel consumption, and recent measurements of on-road diesel vehicle BC emissions, diesel BC emission factors decreased by an order of magnitude over the study period. Reductions in the BC emission factor reflect improved engine technology, emission controls and changes in diesel fuel composition. A new BC monitoring network is needed to continue tracking ambient BC trends because the network of COH monitors has recently been retired.

  15. Correction for a measurement artifact of the Multi-Angle Absorption Photometer (MAAP) at high black carbon mass concentration levels

    Science.gov (United States)

    Hyvärinen, A.-P.; Vakkari, V.; Laakso, L.; Hooda, R. K.; Sharma, V. P.; Panwar, T. S.; Beukes, J. P.; van Zyl, P. G.; Josipovic, M.; Garland, R. M.; Andreae, M. O.; Pöschl, U.; Petzold, A.

    2013-01-01

    The Multi-Angle Absorption Photometer (MAAP) is a widely-used instrument for aerosol black carbon (BC) measurements. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments characterized by high black carbon concentrations. The artifact occurs after a filter spot change - as BC mass is accumulated on a fresh filter spot, the attenuation of the light (raw signal) is weaker than anticipated. This causes a sudden decrease, followed by a gradual increase in measured BC concentration. The artifact is present in the data when the BC concentration exceeds ~3 μg m-3 at the typical MAAP flow rate of 16.7 L min-1 or 1 m3 h-1. The artifact is caused by erroneous dark counts in the photodetector measuring the transmitted light, in combination with an instrument internal averaging procedure of the photodetector raw signals. It was found that, in addition to the erroneous temporal response of the data, concentrations higher than 9 μg m-3 (at the flow rate of 16.7 L min-1) are underestimated by the MAAP. The underestimation increases with increasing BC accumulation rate. At a flow rate of 16.7 L min-1 and concentration of about 24 μg m-3 (BC accumulation rate ~0.4 μg min-1), the underestimation is about 30%. There are two ways of overcoming the MAAP artifact. One method is by logging the raw signal of the 165° photomultiplier measuring the reflected light from the filter spot. As this signal is not affected by the artifact, it can be converted to approximately correct absorption and BC values. However, as the typical print formats of the MAAP do not give the reflected signal as an output, a semi-empirical correction method was developed based on laboratory experiments to correct for the results in the post-processing phase. The correction function was applied to three MAAP datasets from Gual Pahari (India), Beijing (China), and Welgegund (South Africa). In Beijing, the results could also be compared against a

  16. Correction for a measurement artifact of the Multi-Angle Absorption Photometer (MAAP at high black carbon mass concentration levels

    Directory of Open Access Journals (Sweden)

    A.-P. Hyvärinen

    2012-09-01

    Full Text Available The Multi-Angle Absorption Photometer (MAAP is a widely-used instrument for aerosol black carbon observations. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments with high black carbon concentrations. The artifact occurs after a filter spot change – as BC mass is accumulated on a fresh filter spot, the attenuation of the light (raw signal is weaker than anticipated. This causes a sudden decrease, followed by a gradual increase in measured BC concentration. The artifact is present in the data when the BC concentration exceeds ∼3 μg m−3 at the typical MAAP flow rate of 16.7 l min−1 or 1 m3 h−1. The artifact is caused by erroneous dark counts in the photo detector measuring the transmitted light, in combination with an instrument internal averaging procedure of the photo detector raw signals. It was found that in addition to the erroneous temporal response of the data, concentrations higher than 9 μg m−3 (at the flow rate of 16.7 l min−1 are underestimated by the MAAP. The underestimation increases with increasing BC accumulation rate. At a flow rate of 16.7 l min−1 and concentration of about 24 μg m−3 (BC accumulation rate ∼0.4 μg min−1, the underestimation is about 30%. There are two ways of overcoming the MAAP artifact. One method is by logging the raw signal of the 165° photomultiplier measuring the reflected light from the filter spot. As this signal is not affected by the artifact, it can be converted to approximately correct absorption and BC values. However, as the typical print formats of the MAAP do not give the reflected signal as an output, a semi-empirical correction method was developed based on laboratory experiments to correct for the results in the post-processing phase. The correction function was applied to three MAAP datasets from Gual Pahari

  17. Correction for a measurement artifact of the Multi-Angle Absorption Photometer (MAAP at high black carbon mass concentration levels

    Directory of Open Access Journals (Sweden)

    A.-P. Hyvärinen

    2013-01-01

    Full Text Available The Multi-Angle Absorption Photometer (MAAP is a widely-used instrument for aerosol black carbon (BC measurements. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments characterized by high black carbon concentrations. The artifact occurs after a filter spot change – as BC mass is accumulated on a fresh filter spot, the attenuation of the light (raw signal is weaker than anticipated. This causes a sudden decrease, followed by a gradual increase in measured BC concentration. The artifact is present in the data when the BC concentration exceeds ~3 μg m−3 at the typical MAAP flow rate of 16.7 L min−1 or 1 m3 h−1. The artifact is caused by erroneous dark counts in the photodetector measuring the transmitted light, in combination with an instrument internal averaging procedure of the photodetector raw signals. It was found that, in addition to the erroneous temporal response of the data, concentrations higher than 9 μg m−3 (at the flow rate of 16.7 L min−1 are underestimated by the MAAP. The underestimation increases with increasing BC accumulation rate. At a flow rate of 16.7 L min−1 and concentration of about 24 μg m−3 (BC accumulation rate ~0.4 μg min−1, the underestimation is about 30%. There are two ways of overcoming the MAAP artifact. One method is by logging the raw signal of the 165° photomultiplier measuring the reflected light from the filter spot. As this signal is not affected by the artifact, it can be converted to approximately correct absorption and BC values. However, as the typical print formats of the MAAP do not give the reflected signal as an output, a semi-empirical correction method was developed based on laboratory experiments to correct for the results in the post-processing phase. The correction function was applied to three MAAP datasets from

  18. Associations of PM2.5 and black carbon concentrations with traffic, idling, background pollution, and meteorology during school dismissals.

    Science.gov (United States)

    Richmond-Bryant, J; Saganich, C; Bukiewicz, L; Kalin, R

    2009-05-01

    An air quality study was performed outside a cluster of schools in the East Harlem neighborhood of New York City. PM(2.5) and black carbon concentrations were monitored using real-time equipment with a one-minute averaging interval. Monitoring was performed at 1:45-3:30 PM during school days over the period October 31-November 17, 2006. The designated time period was chosen to capture vehicle emissions during end-of-day dismissals from the schools. During the monitoring period, minute-by-minute volume counts of idling and passing school buses, diesel trucks, and automobiles were obtained. These data were transcribed into time series of number of diesel vehicles idling, number of gasoline automobiles idling, number of diesel vehicles passing, and number of automobiles passing along the block adjacent to the school cluster. Multivariate regression models of the log-transform of PM(2.5) and black carbon (BC) concentrations in the East Harlem street canyon were developed using the observation data and data from the New York State Department of Environmental Conservation on meteorology and background PM(2.5). Analysis of variance was used to test the contribution of each covariate to variability in the log-transformed concentrations as a means to judge the relative contribution of each covariate. The models demonstrated that variability in background PM(2.5) contributes 80.9% of the variability in log[PM(2.5)] and 81.5% of the variability in log[BC]. Local traffic sources were demonstrated to contribute 5.8% of the variability in log[BC] and only 0.43% of the variability in log[PM(2.5)]. Diesel idling and passing were both significant contributors to variability in log[BC], while diesel passing was a significant contributor to log[PM(2.5)]. Automobile idling and passing did not contribute significant levels of variability to either concentration. The remainder of variability in each model was explained by temperature, along-canyon wind, and cross-canyon wind, which were

  19. Fine Particulate Matter in São Paulo During the Winter Months: Concentrations and Black Carbon Comparison Between Techniques and Equipments

    Science.gov (United States)

    Miranda, R. M.; Andrade, M. D. F.

    2014-12-01

    During the winter months in São Paulo, Brazil, particulate matter and black carbon were monitored using a Dust Trak (TSI model 8533), a Black Carbon monitor (MAAP-Thermo) and a PM2.5 sampler (Partisol-Thermo). The concentrations were obtained every 5 minutes, from June to August 2014, for the first and second and every 12 hours for the third. The experiment took place in a site at the University of São Paulo which is located in the Southeast part of the Metropolitan Area of São Paulo (MASP). MASP is one of the biggest urban centers of the world, with more than 20 million inhabitants, 10 million vehicles and high values of some regulated pollutants, as particulate matter, especially in winter. Ambient fine particles associated with vehicle emissions have been linked to adverse health effects. Black carbon has a significant share of particulate mass concentrations. Previous studies showed a contribution of more than 30% for São Paulo. This year the climate was atypical in São Paulo. The summer was the driest of the last 30 years. The winter was hot and also dry. Dust trak monitor showed peaks of more than 120 μg/m3 for PM2.5. For a specific period, black carbon concentrations from the MAAP monitor were compared to black carbon measured by optical reflectance on teflon filters collected by the Partisol sampler. Monitor values were around 30% higher, but specific characteristics can influence this value. In the past, optical reflectance and thermal techniques for black carbon were compared. The reflectance technique showed higher results for the fine fraction than the thermal method. Now, reflectance is being compared to instrument measurements and results are also satisfactory.

  20. Measurement of black carbon concentration as an indicator of air quality benefits of traffic restriction policies within the ecopass zone in Milan, Italy

    Science.gov (United States)

    Invernizzi, Giovanni; Ruprecht, Ario; Mazza, Roberto; De Marco, Cinzia; Močnik, Griša; Sioutas, Costantinos; Westerdahl, Dane

    2011-07-01

    Traffic restrictions are an unpopular tool to mitigate urban air pollution, and a measurable improvement in air quality is needed to demonstrate the effectiveness of this measure. Previous attempts failed to detect measurable reductions of PM mass pollution within the areas subject to traffic restriction. However black carbon, which is emitted primarily by traffic sources, could be a PM metric more suitable than PM mass to demonstrate pollutant reductions. In this study we report the results of a black carbon monitoring campaign carried out in Milan, Italy, with the aim to detect - and demonstrate more suitably than PM mass - differences in local urban air quality among three zones located very closely with different traffic intensity. The study was carried out in three different days by measuring simultaneously black carbon and PM mass concentrations with fixed monitoring stations located in three main radial roads connecting the outskirts to the city center, each with three segments: 1) an outer one, with no traffic restrictions 2) an intermediate one, subject to the congestion traffic charge called "Ecopass", where a ticket is required to enter for cars equipped with engines prior to Euro 4 standard; 3) the pedestrian zone (no cars admitted) of Duomo Square in the city center, where each of the three main roads ends. The results demonstrated a sharply declining gradient in black carbon levels from the outer zone, without traffic restrictions, to the more central areas, for all of the three radial main roads. The differences in mean black carbon levels in the same day in the different traffic scheme locations were highly significant for each comparison. In contrast to the Black carbon results, mean PM 10, PM 2.5, PM 1 concentrations did not show significant differences among the different traffic zones on the different campaign days. The ratio of black carbon to PM 10 decreased by 47% and 62% in the Ecopass zone and in the pedestrian zone, respectively, as

  1. Black carbon (BC) of urban topsoil of steel industrial city (Anshan), Northeastern China: Concentration, source identification and environmental implication.

    Science.gov (United States)

    Zong, Yutong; Xiao, Qing; Lu, Shenggao

    2016-11-01

    Black carbon (BC) and total carbon (TC) concentrations in urban topsoils and vertical profiles from steel industrial city, Anshan, Northeastern China, were determined. A total of 115 topsoil samples and 4 soil profiles were collected, in which the BC concentrations were determined using chemical oxidation technique. The BC concentrations in urban topsoils are in the range of 1.86 to 246.46gkg(-1) with an average of 33.86gkg(-1). Both BC and TC concentrations decrease sharply with soil depth, whereas BC/TC ratio shows a little variation with depth. The spatial distribution of BC in urban topsoils reveals that the BC concentration is much higher in the northern part of the city, which is consistent with the steel production. The distribution factors (DF) of BC are the highest in 1000-500 and 500-250μm size fractions, while the lowest in 50-2μm fraction. The mass loading of BC in 250-50 and 50-2μm size fractions accounts for 76.2% of bulk soil, indicating these two size fractions responsible for BC accumulation in soils. Enrichment factor (EF) of BC in urban topsoils ranges from 0.92 to 122.01 with an average of 16.76, indicating that the urban topsoils studied are moderately or severely accumulated by the BC. Strong correlation is found between BC and pollution load index (PLI) of heavy metals, indicating the possibility of similar sources of BC and heavy metals in soils. The BC/TC ratio in soils ranges from 0.45 to 0.97, with an average of 0.75. The BC/TC ratio shows the mixed sources of BC derived from fossil fuel combustion and vehicle emissions. The BC concentration and BC/TC ratio may reflect the degree of industrial activities and pollution sources in urban soils. The study demonstrated that BC is an effective indicator of degree and "hotspots" of heavy metals pollution in urban soils.

  2. Characteristics of black carbon aerosol mass concentration over the East Baltic region from two-year measurements.

    Science.gov (United States)

    Byčenkienė, Steigvilė; Ulevicius, Vidmantas; Kecorius, Simonas

    2011-04-01

    Continuous measurements of black carbon (BC) aerosol mass concentration were performed at a background site Preila (55°55'N, 21°00'E, 5 m a.s.l., Lithuania) during the period 2008-2009. The data were used to characterize the BC mass concentration distribution over the East Baltic region. High increase in aerosol BC concentration was associated with the change in air mass characteristics and biomass burning during the winter heating season and spring wildfires. Monthly means of BC concentration ranged from 212 to 1268 ng m(-3) and the highest hourly means of concentration were from 4800 to 6300 ng m(-3), predominantly in spring and winter months. During the October-April period the BC mass concentrations were about twice as high as those in the summertime. The BC diurnal pattern in winter was typically different from that in spring indicating the seasonal variation of the atmospheric boundary layer height. The weekday/weekend difference was not strongly pronounced because the BC concentrations in Preila are mainly affected by long-range transport or local sources. Typical periodicities caused by anthropogenic and meteorological influences have been identified using Fourier analysis. It was shown that domestic heating appears as a 365 day periodicity; traffic slightly contributes 5-7 day peaks in the spectrum and elevated long-range BC can be identified as characteristic peaks with periodicities in the range from 16 to 29 days.Temporal evolution and transport of BC aerosols were interpreted by the air mass backward trajectory analysis in conjunction with the examination of the wavelength dependence on the aethalometer data. Air masses originated from the North Atlantic Ocean and Scandinavia were favourable for lower BC concentrations (350 ng m(-3)), while the BC level associated with the Western Europe airflows was significantly higher (970 ng m(-3)). The mean values of Ångström exponent of the absorption coefficient (monthly means 1.45 ± 0.25 and 0.84 ± 0

  3. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Science.gov (United States)

    Kanaya, Y.; Komazaki, Y.; Pochanart, P.; Liu, Y.; Akimoto, H.; Gao, J.; Wang, T.; Wang, Z.

    2008-12-01

    Mass concentrations of black carbon (BC) were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l.), located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo), a particle soot absorption photometer (PSAP, Radiance Research), an ECOC semi-continuous analyzer (Sunset Laboratory) and an Aethalometer (AE-21, Magee Scientific). High correlation coefficients (R2>0.88) were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5) concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5) derived from the ECOC analyzer). While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C) tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were recorded when the NOx/NOy ratio was low, implying

  4. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2008-12-01

    Full Text Available Mass concentrations of black carbon (BC were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l., located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo, a particle soot absorption photometer (PSAP, Radiance Research, an ECOC semi-continuous analyzer (Sunset Laboratory and an Aethalometer (AE-21, Magee Scientific. High correlation coefficients (R2>0.88 were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5 concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5 derived from the ECOC analyzer. While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were

  5. Mass concentrations of black carbon measured by four instruments in the middle of Central East China in June 2006

    Directory of Open Access Journals (Sweden)

    Y. Kanaya

    2008-08-01

    Full Text Available Mass concentrations of black carbon (BC were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l., located in the middle of Central East China, using four different instruments: a multi-angle absorption photometer (5012 MAAP, Thermo, a particle soot absorption photometer (PSAP, Radiance Research, an ECOC semi-continuous analyzer (Sunset Laboratory and an Aethalometer (AE-21, Magee Scientific. High correlation coefficients (R2>0.88 were obtained between the measurements of the BC mass concentrations by the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that the BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5 concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5 derived from the ECOC analyzer. This range is significant, but is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from China. In detail, two optical instruments (the MAAP instrument and the PSAP instrument equipped with a heated inlet (400°C tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two possibilities. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC

  6. The seasonal cycle of the mixing layer height and its impact on black carbon concentrations in the Kathmandu Valley (Nepal)

    Science.gov (United States)

    Mues, Andrea; Rupakheti, Maheswar; Hoor, Peter; Bozem, Heiko; Münkel, Christoph; Lauer, Axel; Butler, Tim

    2016-04-01

    The properties and the vertical structure of the mixing layer as part of the planetary boundary layer are of key importance for local air quality. They have a substantial impact on the vertical dispersion of pollutants in the lower atmosphere and thus on their concentrations near the surface. In this study, ceilometer measurements taken within the framework of the SusKat project (Sustainable Atmosphere for the Kathmandu Valley) are used to investigate the mixing layer height in the Kathmandu Valley, Nepal. The applied method is based on the assumption that the aerosol concentration is nearly constant in the vertical and distinctly higher within the mixing layer than in the air above. Thus, the height with the steepest gradient within the ceilometer backscatter profile marks the top of the mixing layer. Ceilometer and black carbon (BC) measurements conducted from March 2013 through February 2014 provide a unique and important dataset for the analysis of the meteorological and air quality conditions in the Kathmandu Valley. In this study the mean diurnal cycle of the mixing layer height in the Kathmandu Valley for each season (pre-monsoon, monsoon, post-monsoon and winter season) and its dependency on the meteorological situation is investigated. In addition, the impact of the mixing layer height on the BC concentration is analyzed and compared to the relevance of other important processes such as emissions, horizontal advection and deposition. In all seasons the diurnal cycle is typically characterized by low mixing heights during the night, gradually increasing after sun rise reaching to maximum values in the afternoon before decreasing again. Seasonal differences can be seen particularly in the height of the mixing layer, e.g. from on average 153/1200 m (pre-monsoon) to 241/755 m (monsoon season) during the night/day, and the duration of enhanced mixing layer heights during daytime (around 12 hours (pre-monsoon season) to 8 hours (winter)). During the monsoon

  7. Wildfires in a warmer climate: Emission fluxes, emission heights, and black carbon concentrations in 2090-2099

    Science.gov (United States)

    Veira, A.; Lasslop, G.; Kloster, S.

    2016-04-01

    Global warming is expected to considerably impact wildfire activity and aerosol emission release in the future. Due to their complexity, the future interactions between climate change, wildfire activity, emission release, and atmospheric aerosol processes are still uncertain. Here we use the process-based fire model SPITFIRE within the global vegetation model JSBACH to simulate wildfire activity for present-day climate conditions and future Representative Concentration Pathways (RCPs). The modeled fire emission fluxes and fire radiative power serve as input for the aerosol-climate model ECHAM6-HAM2, which has been extended by a semiempirical plume height parametrization. Our results indicate a general increase in extratropical and a decrease in tropical wildfire activity at the end of the 21st century. Changes in emission fluxes are most pronounced for the strongest warming scenario RCP8.5 (+49% in the extratropics, -37% in the tropics). Tropospheric black carbon (BC) concentrations are similarly affected by changes in emission fluxes and changes in climate conditions with regional variations of up to -50% to +100%. In the Northern Hemispheric extratropics, we attribute a mean increase in aerosol optical thickness of +0.031±0.002 to changes in wildfire emissions. Due to the compensating effects of fire intensification and more stable atmospheric conditions, global mean emission heights change by at most 0.3 km with only minor influence on BC long-range transport. The changes in wildfire emission fluxes for the RCP8.5 scenario, however, may largely compensate the projected reduction in anthropogenic BC emissions by the end of the 21st century.

  8. Polycyclic aromatic hydrocarbons and black carbon in intertidal sediments of China coastal zones: Concentration, ecological risk, source and their relationship

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaofei [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Hou, Lijun [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Li, Ye [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Liu, Min, E-mail: mliu@geo.ecnu.edu.cn [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Key Laboratory of Geographic Information Science, Ministry of Education, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Lin, Xianbiao; Cheng, Lv [School of Geographical Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China)

    2016-10-01

    Polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) have attracted many attentions, especially in the coastal environments. In this study, spatiotemporal distributions of PAHs and BC, and the correlations between BC and PAHs were investigated in the intertidal sediments of China coastal zones. BC in sediments was measured through dichromate oxidation (BC{sub Cr}) and thermal oxidation (BC{sub CTO}). The concentrations of BC{sub Cr} in the intertidal sediments ranged between 0.61 and 6.32 mg g{sup −1}, while BC{sub CTO} ranged between 0.57 and 4.76 mg g{sup −1}. Spatial variations of δ{sup 13}C signatures in TOC and BC were observed, varying from − 21.13‰ to − 24.87‰ and from − 23.53‰ to − 16.78‰, respectively. PAH contents of sediments ranged from 195.9 to 4610.2 ng g{sup −1} in winter and 98.2 to 2796.5 ng g{sup −1} in summer, and significantly seasonal variations were observed at most sampling sites. However, the results of potential toxicity assessment indicated low ecological risk in the intertidal sediments of China coastal zones. Greater concentrations of PAHs measured in the sediments of estuarine environments indicated that rivers runoff may have been responsible for the higher PAH pollution levels in the intertidal sediments of China coastal zones. Pearson's correlation analysis suggested that pyrogenic compounds of PAH were significantly related to BC, due to that both BC and these compounds derived mainly from the combustion process of fossil fuels and biomass. Overall, increasing energy consumptions caused by anthropogenic activities can contribute more emissions of BC as well as PAHs and thus improve the importance of BC in indicating pyrogenic compounds of PAHs in the intertidal sediments of China coastal zones. - Highlights: • River runoffs were responsible for the high PAH pollution levels in the study area. • BC and PAHs derived mainly from the combustion process of fossil fuels. • BC was associated

  9. Black carbon concentrations in the highly polluted Kathmandu Valley, Nepal: a three year monitoring with a dual-spot Aethalometer

    Science.gov (United States)

    Rupakheti, Maheswar; Drinovec, Luka; Puppala, SivaPraveen; Mahata, Khadak; Rupakheti, Dipesh; Kathayat, Bhogendra; Singdan, Pratik; Panday, Arnico; Lawrence, Mark

    2016-04-01

    Our knowledge about ambient black carbon (BC) in the vast Himalayan region, a region vulnerable to impacts of global warming, is very limited due to unavailability of a long-term ambient monitoring. Here we present results from a continuous monitoring of ambient BC concentrations, with a new generation Aethalometer (AE33), over a three year period (January 2013- January 2016) at a semi-urban site in the highly polluted Kathmandu Valley in the foothills of the central Himalaya, one of the most polluted cities in the world. This is the longest time series of BC concentrations that have been monitored with AE33 (which uses the dual-spot technique for a real-time filter loading compensation) in highly polluted ambient environment. The measurements were carried out under the framework of project SusKat (Sustainable Atmosphere for the Kathmandu Valley). BC concentrations were found to be extremely high, especially in winter and the pre-monsoon period, with the hourly-averaged values often exceeding 50 μg/m3. BC concentrations showed a clear diurnal cycle with a prominent peak around 8-9 am and a second peak around 8-9 pm local time in all four seasons. Night-time BC was also fairly high. The diurnal cycle was driven by a combination of increased emissions from traffic, cooking activities, garbage burning, and lower mixing heights (˜200 m) and reduced horizontal ventilation in the mornings and evenings. BC concentrations showed significant seasonal variations - a maximum in winter season and minimum during the monsoon (rainy) season, with monthly average values in the range 5-30 μg/m3. An increase in emissions from the operation of over 100 brick kilns in winter and spring, and an increase in the use of small but numerous diesel power generators during hours with power cuts contributed significantly to ambient BC concentrations in the valley. Fractional contributions of biomass burning and fossil fuel combustion to BC was estimated based on a real-time method for

  10. Correlation of black carbon aerosol and carbon monoxide concentrations measured in the high-altitude environment of Mt. Huangshan, Eastern China

    Directory of Open Access Journals (Sweden)

    X. L. Pan

    2011-02-01

    Full Text Available Understanding the relationship between black carbon (BC and carbon monoxide (CO will help improve BC emission inventories and the evaluation of global/regional climate forcing effects. In the present work, the BC (PM1 and CO mixing ratio was continuously measured at a~high-altitude background station on the summit of Mt Huangshan between 2006 and 2009. Annual mean BC concentration was 654.6 ± 633.4 ng m−3 with maxima in spring and autumn, when biomass was burned over a large area in Eastern China. The yearly averaged CO concentration was 446.4 ± 167.6 ppbv, and the increase in the CO concentration was greatest in the cold season, implying that the large-scale domestic coal/biofuel combustion for heating has an effect. The BC–CO relationship was found to have different seasonal features but strong positive correlation (R > 0.8. Back trajectory cluster analysis showed that the ΔBC/ΔCO ratio of plumes from the Yangtze River Delta region was 6.58 ± 0.96 ng m−3 ppbv−1, which is consistent with result from INTEX-B emission inventory. The ΔBC/ΔCO ratios for air masses from Northern, Central Eastern and Southern China were 5.2 ± 0.63, 5.65 ± 0.58 and 5.21 ± 0.93 ng m−3 ppbv−1, respectively. Over the whole observation period, the ΔBC/ΔCO ratio had unimodal diurnal variations and had a maximum during the day (09:00–17:00 LST and minimum at night (21:00–04:00 LST in spring, summer, autumn and winter, indicating the effects of the intrusion of clean air mass from the high troposphere. The case study combined with measurements of urban PM10 concentrations and satellite observations demonstrated that the ΔBC/ΔCO ratio for a plume of burning biomass was 12.4 ng m−3 ppbv−1 and that for urban plumes in Eastern China was 5.3 ± 0.53 ng m−3 ppbv−1. Transportation and industry were deemed as

  11. Phenology of a Vegetation Barrier and Resulting Impacts on Near-Highway Particle Number and Black Carbon Concentrations on a School Campus

    Directory of Open Access Journals (Sweden)

    Christina H. Fuller

    2017-02-01

    Full Text Available Traffic-related air pollution is a persistent concern especially in urban areas where populations live in close proximity to roadways. Innovative solutions are needed to minimize human exposure and the installation of vegetative barriers shows potential as a method to reduce near-road concentrations. This study investigates the impact of an existing stand of deciduous and evergreen trees on near-road total particle number (PNC and black carbon (BC concentrations across three seasons. Measurements were taken during spring, fall and winter on the campus of a middle school in the Atlanta (GA, USA area at distances of 10 m and 50 m from a major interstate highway. We identified consistent decreases in BC concentrations, but not for PNC, with increased distance from the highway. In multivariable models, hour of day, downwind conditions, distance to highway, temperature and relative humidity significantly predicted pollutant concentrations. The magnitude of effect of these variables differed by season, however, we were not able to show a definitive impact of the vegetative barrier on near-road concentrations. More detailed studies are necessary to further examine the specific configurations and scenarios that may produce pollutant and exposure reductions.

  12. Assessing Single Particle Soot Photometer and Integrating Sphere/Integrating Sandwich Spectrophotometer measurement techniques for quantifying black carbon concentration in snow

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    J. P. Schwarz

    2012-11-01

    Full Text Available We evaluate the performance of the Single Particle Soot Photometer (SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW in quantifying the concentration of refractory black carbon (BC in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60% than for atmospheric sampling (<30%. Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow can exist in larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the ISSW revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow or ice formed from fallen snow using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

  13. Phenology of a Vegetation Barrier and Resulting Impacts on Near-Highway Particle Number and Black Carbon Concentrations on a School Campus.

    Science.gov (United States)

    Fuller, Christina H; Carter, David R; Hayat, Matthew J; Baldauf, Richard; Watts Hull, Rebecca

    2017-02-08

    Traffic-related air pollution is a persistent concern especially in urban areas where populations live in close proximity to roadways. Innovative solutions are needed to minimize human exposure and the installation of vegetative barriers shows potential as a method to reduce near-road concentrations. This study investigates the impact of an existing stand of deciduous and evergreen trees on near-road total particle number (PNC) and black carbon (BC) concentrations across three seasons. Measurements were taken during spring, fall and winter on the campus of a middle school in the Atlanta (GA, USA) area at distances of 10 m and 50 m from a major interstate highway. We identified consistent decreases in BC concentrations, but not for PNC, with increased distance from the highway. In multivariable models, hour of day, downwind conditions, distance to highway, temperature and relative humidity significantly predicted pollutant concentrations. The magnitude of effect of these variables differed by season, however, we were not able to show a definitive impact of the vegetative barrier on near-road concentrations. More detailed studies are necessary to further examine the specific configurations and scenarios that may produce pollutant and exposure reductions.

  14. Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN

    Directory of Open Access Journals (Sweden)

    W. Birmili

    2015-11-01

    Full Text Available The German Ultrafine Aerosol Network (GUAN is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both, climate and health related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at seventeen observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained (doi:10.5072/guan.

  15. Measurements of Mass Concentrations of Black Carbon by Using Four Instruments at the Summit of Mount Tai, in the Center of the North China Plain in June 2006

    Science.gov (United States)

    Kanaya, Y.; Komazaki, Y.; Pochanart, P.; Liu, Y.; Akimoto, H.; Gao, J.; Wang, T.; Wang, Z.

    2007-12-01

    Although the emission rate of black carbon (BC) aerosols from the North China Plain (NCP) has been estimated to be high and it would impact climate severely, the BC mass concentrations at a regionally representative location in the plain have been scarcely observed. During a comprehensive field campaign performed at the summit of Mount Tai (36.26 N, 117.11 E, 1534 m asl) in June 2006, BC (or elemental carbon, EC) concentrations were measured by four instruments: an Aethalometer, a Multi-Angle Absorption Photometry (MAAP) instrument, a Particle Soot Absorption Photometer, and a semi-continuous ECOC analyzer with two thermal protocols (IMPROVE and NIOSH). The hourly BC concentration (PM2.5) as measured by the MAAP instrument ranged from -0.1 to 40.8 μgC m-3, with an average of 3.7 μgC m-3. For both of the first 20-day and the latter 10-day periods during the campaign, for which all the instruments provided PM1 and PM2.5 measurements, respectively, we found strong correlations (R2 >0.88) for all the pairs with which >30 hours of coincident observations were made. The slopes and the intercept values of regression lines ranged from 1.00 to 1.42 and from -0.2 to +0.8 μgC m-3, respectively. This general agreement suggested that we were able to determine the BC concentrations regionally representative over the NCP with an uncertainty of ±50% and thereby reduce the uncertainty factor of >4 associating with the BC emission rate from China. The temporal variation of BC concentrations in June 2006 was dominated by the influence from crop (winter wheat) residue burning after the harvest. The relative importance of BC in comparison to CO2 in terms of heating of the atmosphere over this region is also discussed.

  16. Comparison of Spheroidal Carbonaceous Particle Data with Modelled Atmospheric Black Carbon Concentration and Deposition and Air Mass Sources in Northern Europe, 1850–2010

    Directory of Open Access Journals (Sweden)

    Meri Ruppel

    2013-01-01

    Full Text Available Spheroidal carbonaceous particles (SCP are a well-defined fraction of black carbon (BC, produced only by the incomplete combustion of fossil fuels such as coal and oil. Their past concentrations have been studied using environmental archives, but, additionally, historical trends of BC concentration and deposition can be estimated by modelling. These models are based on BC emission inventories, but actual measurements of BC concentration and deposition play an essential role in their evaluation and validation. We use the chemistry transport model OsloCTM2 to model historical time series of BC concentration and deposition from energy and industrial sources and compare these to sedimentary measurements of SCPs obtained from lake sediments in Northern Europe from 1850 to 2010. To determine the origin of SCPs we generated back trajectories of air masses to the study sites. Generally, trends of SCP deposition and modelled results agree reasonably well, showing rapidly increasing values from 1950, to a peak in 1980, and a decrease towards the present. Empirical SCP data show differences in deposition magnitude between the sites that are not captured by the model but which may be explained by different air mass transport patterns. The results highlight the need for numerous observational records to reliably validate model results.

  17. Black carbon in aerosol during BIBLE B

    Science.gov (United States)

    Liley, J. Ben; Baumgardner, D.; Kondo, Y.; Kita, K.; Blake, D. R.; Koike, M.; Machida, T.; Takegawa, N.; Kawakami, S.; Shirai, T.; Ogawa, T.

    2003-02-01

    The Biomass Burning and Lightning Experiment (BIBLE) A and B campaigns over the tropical western Pacific during springtime deployed a Gulfstream-II aircraft with systems to measure ozone and numerous precursor species. Aerosol measuring systems included a MASP optical particle counter, a condensation nucleus (CN) counter, and an absorption spectrometer for black carbon. Aerosol volume was very low in the middle and upper troposphere during both campaigns, and during BIBLE A, there was little aerosol enhancement in the boundary layer away from urban areas. In BIBLE B, there was marked aerosol enhancement in the lowest 3 km of the atmosphere. Mixing ratios of CN in cloud-free conditions in the upper troposphere were in general higher than in the boundary layer, indicating new particle formation from gaseous precursors. High concentrations of black carbon were observed during BIBLE B, with mass loadings up to 40 μg m-3 representing as much as one quarter of total aerosol mass. Strong correlations with hydrocarbon enhancement allow the determination of a black carbon emission ratio for the fires at that time. Expressed as elemental carbon, it is about 0.5% of carbon dioxide and 6% of carbon monoxide emissions from the same fires, comparable to methane production, and greater than that of other hydrocarbons.

  18. Carbon Concentration of Austenite

    Directory of Open Access Journals (Sweden)

    Z. Ławrynowicz

    2007-07-01

    Full Text Available The investigation was carried out to examine the influence of temperature and times of austempering process on the maximum extend towhich the bainite reaction can proceed and the carbon content in retained austenite. It should be noted that a small percentage change in theaustenite carbon content can have a significant effect on the subsequent austempering reaction changing the volume fraction of the phasespresent and hence, the resulting mechanical properties. Specimens were prepared from an unalloyed ductile cast iron, austenitised at 950oCfor 60 minutes and austempered by the conventional single-step austempering process at four temperatures between BS and MS, eg., 250,300, 350 and 400oC. The samples were austempered at these temperatures for 15, 30, 60, 120 and 240 minutes and finally quenched toambient temperature. Volume fractions of retained austenite and carbon concentration in the residual austenite have been observed byusing X-ray diffraction. Additionally, carbon concentration in the residual austenite was calculated using volume fraction data of austeniteand a model developed by Bhadeshia based on the McLellan and Dunn quasi-chemical thermodynamic model. The comparison ofexperimental data with the T0, T0' and Ae3' phase boundaries suggests the likely mechanism of bainite reaction in cast iron is displacive rather than diffusional. The carbon concentration in retained austenite demonstrates that at the end of bainite reaction the microstructure must consist of not only ausferrite but additionally precipitated carbides.

  19. 杨卫芬,程钟,沈琰%The Concentration Variation Characteristics of Black Carbon Aerosols in Changzhou in Autumn and Winter

    Institute of Scientific and Technical Information of China (English)

    杨卫芬; 程钟; 沈琰

    2013-01-01

    根据常州市2012年9月-2013年1月的黑炭气溶胶( Black Carbon ,以下简称BC)在线监测数据及常规气象资料,分析了BC在秋冬季不同时间段的变化特征及气象要素对BC的影响。结果表明,常州秋冬季BC平均值为5.17(1.48~17.02)μg/m3,主要集中在1.00μg/m3~7.50μg/m3,冬季较高于秋季,小时均值最大值达33.87μg/m3;BC本底值为3.50μg/m3;1月份BC日均值变化幅度最大,发生高污染的频率最高。 BC的日变化具有明显的双峰结构,一天中最大浓度多出现在上午06:00-09:00,特殊天气条件下,BC小时值存在不同的分布情况;BC在不同风向的输送条件下有明显的不同,偏东北方向过来的气团易造成BC高污染。%In order to study the pollution characteristics of the black carbon aerosol ( BC ) in autumn and winter in Changzhou , the variation characteristics of BC on different time scales and the effects of meteorological factors on the BC mass concentration were analyzed based on BC online monitoring data and the regular meteoro -logical data in Changzhou from September 2012 to January 2013 .The results showed that the average BC concen-tration during autumn and winter in Changzhou was 5.17 μg/m3 , with the range 1.48 μg/m3 ~17.02 μg/m3 . BC mass concentration was concentrated around the range 1.00μg/m3 ~7.50μg/m3 , with maximum hourly av-erage concentration of 33 .87 μg/m3 .In addition , the concentration of BC in winter was higher than that in au-tumn and the base BC mass concentration of this study area was about 3.50 μg/m3 based on the maximum fre-quency of hourly mean concentration .The biggest variation tendency of daily average BC mass concentration oc-curred in January , which was also the time of high pollution occurred frequently .The daily variation of BC mass concentration was characterized by a pronounced double peak pattern , and the highest value occurred more dur-ing 06

  20. Black carbon concentrations from a Tibetan Plateau ice core spanning 1843–1982: recent increases due to emissions and glacier melt

    Directory of Open Access Journals (Sweden)

    M. Jenkins

    2013-10-01

    Full Text Available Black carbon (BC deposited on snow and glacier surfaces can reduce albedo and lead to accelerated melt. An ice core recovered from Guoqu glacier on Mt. Geladaindong and analyzed using a Single Particle Soot Photometer provides the first long-term (1843–1982 record of BC concentrations from the Central Tibetan Plateau. The highest concentrations are observed from 1975–1982, which corresponds to a 2.0-fold and 2.4-fold increase in average and median values, respectively, relative to 1843–1940. BC concentrations post-1940 are also elevated relative to the earlier portion of the record. Causes for the higher BC concentrations include increased regional BC emissions and subsequent deposition, and melt induced enrichment of BC, with the melt potentially accelerated due to the presence of BC at the glacier surface. A qualitative comparison of the BC and Fe (used as a dust proxy records suggests that if changes in the concentrations of absorbing impurities at the glacier surface have influenced recent glacial melt, the melt may be due to the presence of BC rather than dust. Guoqu glacier has received no net ice accumulation since the 1980s, and is a potential example of a glacier where an increase in the equilibrium line altitude is exposing buried high impurity layers. That BC concentrations in the uppermost layers of the Geladaindong ice core are not substantially higher relative to deeper in the ice core suggests that some of the BC that must have been deposited on Guoqu glacier via wet or dry deposition between 1983 and 2005 has been removed from the surface of the glacier, potentially via supraglacial or englacial meltwater.

  1. Concentration and 14C Content of Total Organic Carbon and Black Carbon in Small (<100 ug C) Samples from Low-Latitude Alpine Ice Cores

    Science.gov (United States)

    Kehrwald, N. M.; Czimczik, C. I.; Santos, G. M.; Thompson, L. G.; Ziolkowski, L.

    2008-12-01

    Many low latitude glaciers are receding with consequences for the regional energy budget and hydrology. Ice loss has been linked to climate change and the deposition of organic aerosols such as black carbon (BC) which is formed during incomplete combustion. Little is known about how the contents of BC and total organic carbon (TOC) in aerosols change over time and how anthropogenic activities (e.g. land-use change) impact this variability. Low-latitude ice cores are located closer to population centers than polar ice caps and can provide a regional synthesis of TOC and BC variability. Radiocarbon (14C) may be used to partition BC aerosols into fossil (>50 kyrs) and modern sources (e.g. fossil-fuels vs. wildfires). We quantified TOC, BC, and their 14C content in three low-latitude ice cores: Naimona'nyi (30°27'N, 81°91'E) and Dasuopu (28°23'N, 85°43'E), Tibet, and Quelccaya (13°56'S; 70°50'W), Peru. Aerosols (52-256 g ice on filters) were separated into TOC and BC using thermal oxidation (CTO- 375). 14C was measured by AMS. TOC contents were 0.11-0.87, 0.05-0.43, and 0.06-0.19 μg C (g ice) -1 for Naimona'nyi, Dasuopu, and Quelccaya, respectively. BC contents were 18±8, 27±4, and 29±12 %TOC. Procedural blanks were 0.8 ± 0.4 μg C (TOC) and 1.2 ± 0.6 μg C (BC). In ice cores well dated through annual layer counting and/or independent ages (e.g. volcanic horizons) such as Quelccaya, the ability to separate BC from TOC, as well as partition BC into fossil and modern contributions has potential for reconstructing pre- and post-industrial changes in aerosol composition and their impact on the energy budget.

  2. Surface analysis of carbon black waste materials from tire residues

    Science.gov (United States)

    Lee, W. H.; Kim, J. Y.; Ko, Y. K.; Reucroft, P. J.; Zondlo, J. W.

    1999-03-01

    X-ray photoelectron spectroscopy (XPS) has been used to obtain surface chemical state information on two carbon black waste materials in terms of the surface element distribution/concentration and chemical structure. Small amounts of sulfur in the form of CS 2 were detected on the surface (less than 1.7 mass %). C-H/C-C was the major carbon functional component on the surface of carbon black samples but other functional forms of carbon were also present such as CO and C-O. The surface of the carbon black obtained from a hydropyrolysis process was highly oxidized primarily in the form of carbon based oxygen groups. On the other hand, surface oxygen atoms on the surface of the carbon black obtained from a pyrolysis process in the absence of H 2 were in the form of both metal oxides and carbon based oxygen groups.

  3. Assessing the impact of the forthcoming decrease in diesel exhaust particulate matter emissions on air quality: implications for black carbon concentrations in ambient air

    Science.gov (United States)

    González, Y.; Rodríguez, S.; Cuevas, E.; Ramos, R.; Abreu-Afonso, J.; Baldasano, J. M.

    2009-04-01

    Forthcoming regulations (e.g. EURO 5 and EURO 6) are planned to reduce particulate matter emissions (PM) in the exhaust of forthcoming vehicles. In this study we assess the impact of such reduction in the diesel PM exhaust emissions on the urban ambient air PM concentrations. This has been done by studying the relationship between black carbon (BC) and carbon monoxide (CO) in urban ambient air and in the exhaust of current and forthcoming vehicles. The slope of the BC-vs-CO linear relationship is mainly affected by the percentage (%) of diesel automobiles in the urban vehicles fleet. This slope is a better indicator of the diesel PM emissions than bulk BC concentrations in urban ambient air. BC-vs-CO slopes within the range 1-3 and 7-14 ngBC/µgCO are typically observed in urban areas with low (fuel consumption for on road transportation, respectively. The entry into force of forthcoming regulations will decrease the BC-vs-CO slope in urban ambient air from about 10 to 5 ngBC/µgCO in the next decade, according to calculations based on the current data on diesel vehicles in urban fleets in Spanish cities. However, this will not necessary prompt a significant decrease in the urban BC concentrations if road traffic volume follows the increasing trend of the last decade. The results of this study shows that the analysis of the BC-vs-CO slope trend in ambient air is an useful tool for understanding the involvement "of the changes in the vehicle exhaust emissions rates" and "of the changes in the road traffic volume" in the BC and PMx trends in urban ambient air.

  4. A multi-site analysis of the association between black carbon concentrations and vehicular idling, traffic, background pollution, and meteorology during school dismissals.

    Science.gov (United States)

    Richmond-Bryant, J; Bukiewicz, L; Kalin, R; Galarraga, C; Mirer, F

    2011-05-01

    A study was performed to assess the relationship between black carbon (BC), passing traffic, and vehicular idling outside New York City (NYC) schools during student dismissal. Monitoring was performed at three school sites in East Harlem, the Bronx, and Brooklyn for 1month per year over a two-year period from November 2006-October 2008. Monitoring at each site was conducted before and after the Asthma Free School Zone (AFSZ) asthma reduction education program was administered. Real-time equipment with a one-minute averaging interval was used to obtain the BC data, while volume counts of idling and passing school busses, trucks, and automobiles were collected each minute by study staff. These data were matched to ambient PM(2.5) and meteorology data obtained from the New York State Department of Environmental Conservation. A generalized additive model (GAM) model was run to examine the relationship between BC concentration and each variable while accounting for site-to-site differences. F-tests were employed to assess the significance of each of the predictor variables. The model results suggested that variability in ambient PM(2.5) concentration contributed 24% of the variability in transformed BC concentration, while variability in the number of idling busses and trucks on the street during dismissal contributed 20% of the variability in transformed BC concentration. The results of this study suggest that a combination of urban scale and local traffic control approaches in combination with cessation of school bus idling will produce improved local BC concentration outside schools.

  5. Monitoring of black carbon and size-segregated particle number concentrations at 9-m and 65-m distances from a major road in Helsinki

    Energy Technology Data Exchange (ETDEWEB)

    Pakkanen, T.A.; Maekelae, T.; Hillamo, R.E. [Finnish Meteorological Inst., Helsinki (Finland); Virtanen, A.; Roenkkoe, T.; Keskinen, J. [Tampere Univ. of Technology, Inst. of Physics, Aerosol Physics Lab. , Tampere (Finland); Pirjola, L.; Parviainen, H. [Helsinki Polytechnic, Dept. of Technology, Helsinki (Finland); Hussein, T.; Haemeri, K. [Helsinki Univ., Dept. of Physical Sciences, Helsinki (Finland)

    2006-07-01

    In February and August 2003, black carbon (BC) and size-segregated particle number concentrations were monitored simultaneously at 9-m and 65-m distances from a major road in Helsinki, Finland, using aethalometers and electrical low-pressure impactors, respectively. During weekdays in winter, the average total particle number concentrations in the diameter range 0.007-1{mu}m increased during morning rush hours from the nighttime values of 17000 and 12000 cm{sup -3} to 190000 and 130000 cm{sup -3} at the 9-m and 65-m stations, respectively. The corresponding BC concentrations increased from 730 and 430 ng m{sup -3} to 2800 and 1550 ng m{sup -3}. Compared with those in winter, the average rush-hour particle number concentrations were much lower in summer, the likely reason being enhanced nucleation in cold winter conditions. BC concentrations were slightly higher during summer than during winter. Number size distributions measured at the 9-m and 65-m distances and at a background site had similar modal characteristics with the highest peak occurring below 0.03 {mu}m. Despite the different wind conditions in winter and summer, concentrations of total particle number and BC decreased similarly between the 9-m and 65-m stations, the likely principal mechanism being mixing with background air. The strong diurnal variation in concentrations during the weekdays, together with the large concentration difference between the 9-m and 65-m distances, suggests that local traffic was the main source of the measured pollutants, especially during rush hours at the 9-m site. In winter, the decrease in the particle number concentrations from the 9-m site to the 65-m site was most pronounced for the smallest exhaust particles. During an episodic pollution event in winter there were indications of condensational growth of 0.007-0.03 {mu}m particles, which increased the number concentration of 0.03-0.06 {mu}m particles at the 65-m site. (orig.)

  6. Black carbon measurements using an integrating sphere

    Science.gov (United States)

    Hitzenberger, R.; Dusek, U.; Berner, A.

    1996-08-01

    An integrating sphere was used to determine the black carbon (BC) content of aerosol filter samples dissolved in chloroform (method originally described by Heintzenberg [1982]). The specific absorption coefficient Ba (equal to absorption per mass) of the samples was also measured using the sphere as an integrating detector for transmitted light. Comparing the Ba of ambient samples taken in Vienna, Austria, to the BC concentrations measured on the dissolved filters, a value of approximately 6 m2/g was found to be a reasonable value for the Ba of the black carbon found at the site. The size dependence of Ba of a nebulized suspension of soot was measured using a rotating impactor, and a reasonable agreement between measured and calculated values was found.

  7. Applicability of a noise-based model to estimate in-traffic exposure to black carbon and particle number concentrations in different cultures.

    Science.gov (United States)

    Dekoninck, Luc; Botteldooren, Dick; Panis, Luc Int; Hankey, Steve; Jain, Grishma; S, Karthik; Marshall, Julian

    2015-01-01

    Several studies show that a significant portion of daily air pollution exposure, in particular black carbon (BC), occurs during transport. In a previous work, a model for the in-traffic exposure of bicyclists to BC was proposed based on spectral evaluation of mobile noise measurements and validated with BC measurements in Ghent, Belgium. In this paper, applicability of this model in a different cultural context with a totally different traffic and mobility situation is presented. In addition, a similar modeling approach is tested for particle number (PN) concentration. Indirectly assessing BC and PN exposure through a model based on noise measurements is advantageous because of the availability of very affordable noise monitoring devices. Our previous work showed that a model including specific spectral components of the noise that relate to engine and rolling emission and basic meteorological data, could be quite accurate. Moreover, including a background concentration adjustment improved the model considerably. To explore whether this model could also be used in a different context, with or without tuning of the model parameters, a study was conducted in Bangalore, India. Noise measurement equipment, data storage, data processing, continent, country, measurement operators, vehicle fleet, driving behavior, biking facilities, background concentration, and meteorology are all very different from the first measurement campaign in Belgium. More than 24h of combined in-traffic noise, BC, and PN measurements were collected. It was shown that the noise-based BC exposure model gives good predictions in Bangalore and that the same approach is also successful for PN. Cross validation of the model parameters was used to compare factors that impact exposure across study sites. A pooled model (combining the measurements of the two locations) results in a correlation of 0.84 when fitting the total trip exposure in Bangalore. Estimating particulate matter exposure with traffic

  8. High black carbon and ozone concentrations during pollution transport in the Himalayas: five years of continuous observations at NCO-P global GAW station.

    Science.gov (United States)

    Marinoni, A; Cristofanelli, P; Laj, P; Duchi, R; Putero, D; Calzolari, F; Landi, T C; Vuillermoz, E; Maione, M; Bonasoni, P

    2013-08-01

    To study the influence of polluted air-mass transport carrying ozone (O3) and black carbon (BC) in the high Himalayas, since March 2006 the Nepal Climate Observatory at Pyramid (NCO-P) GAW-WMO global station (Nepal, 5079 m a.s.l.) is operative. During the first 5-year measurements, the O3 and BC concentrations have shown a mean value of 48 +/- 12 ppb (+/- standard deviation) and 208 +/- 374 ng/m3, respectively. Both O3 and BC showed well defined seasonal cycles with maxima during pre-monsoon (O3: 61.3 +/- 7.7 ppbV; BC: 444 +/- 433 ng/m3) and minima during the summer monsoon (O3: 40.1 +/- 12.4 ppbV; BC: 64 +/- 101 ng/m3). The analysis of the days characterised by the presence of a significant BC increase with respect to the typical seasonal cycle identified 156 days affected by "acute" pollution events, corresponding to 9.1% of the entire data-set. Such events mostly occur in the pre-monsoon period, when the O3 diurnal variability is strongly related to the transport of polluted air-mass rich on BC. On average, these "acute" pollution events were characterised by dramatic increases of BC (352%) and O3 (29%) levels compared with the remaining days.

  9. High black carbon and ozone concentrations during pollution transport in the Himalayas: Five years of continuous observations at NCO-P global GAW station

    Institute of Scientific and Technical Information of China (English)

    A.Marinoni; P.Cristofanelli; P.Laj; R.Duchi; D.Putero; F.Calzolari; T.C.Landi

    2013-01-01

    To study the influence of polluted air-mass transport carrying ozone (O3) and black carbon (BC) in the high H-hmalayas,since March 2006 the Nepal Climate Observatory at Pyramid (NCO-P) GAW-WMO global station (Nepal,5079 m a.s.l.) is operative.During the first 5-year measurements,the O3 and BC concentrations have shown a mean value of 48 ± 12 ppb (± standard deviation) and 208 ± 374 ng/m3,respectively.Both O3 and BC showed well defined seasonal cycles with maxima during pre-monsoon (O3:61.3 ± 7.7 ppbV; BC:444 ± 433 ng/m3) and minima during the summer monsoon (O3:40.1 ± 12.4 ppbV; BC∶ 64 ± 101 ng/m3).The analysis of the days characterised by the presence of a significant BC increase with respect to the typical seasonal cycle identified 156 days affected by "acute" pollution events,corresponding to 9.1% of the entire data-set.Such events mostly occur in the pre-monsoon period,when the O3 diurnal variability is strongly related to the transport of polluted air-mass rich on BC.On average,these "acute" pollution events were characterised by dramatic increases of BC (352%) and O3 (29%) levels compared with the remaining days.

  10. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern~Pyrenees, 1570 m a.s.l.

    Directory of Open Access Journals (Sweden)

    A. Ripoll

    2013-10-01

    Full Text Available Time variation of mass particulate matter (PM1 and PM1−10, black carbon (BC and particle number (N concentrations at the high altitude site of Montsec (MSC in the southern Pyrenees was interpreted for the period 2010–2012. The MSC site registered higher PM10 (12 μg m−3 and N > 7 nm (2209 # cm−3 concentrations than those measured at other high altitude sites in central Europe (PM10: 3–9 μg m−3 and N: 634–2070 # cm−3. By contrast, BC concentrations at MSC (0.2 μg m−3 were equal or even lower than those measured at these European sites (0.2–0.4 μg m−3. These differences were attributed to the lower influence of anthropogenic emissions and to the higher relevance of Saharan dust transport and new particle formation (NPF processes at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African outbreaks (PM1−10: 13 μg m−3, PM1: 8 μg m−3 and BC: 0.3 μg m−3 and low concentrations when Atlantic advections occurred (PM1−10: 5 μg m−3, PM1: 4 μg m−3 and BC: 0.1 μg m−3. Because of the contrasting origin of the air masses in the warmer seasons (spring and summer and in the colder seasons (autumn and winter, PM and BC concentrations showed a marked increase in summer, with a secondary maximum in early spring, and were at their lowest during winter. The maximum in the warmer seasons was attributed to long-range transport processes which mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles with maxima at midday in the colder seasons. A statistically significant weekly variation was also obtained for the BC concentrations, displaying a progressive increase from Tuesday to

  11. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern Pyrenees, 1570 m a.s.l.)

    Science.gov (United States)

    Ripoll, A.; Pey, J.; Minguillón, M. C.; Pérez, N.; Pandolfi, M.; Querol, X.; Alastuey, A.

    2014-04-01

    Time variation of mass particulate matter (PM1 and PM1&minus10), black carbon (BC) and number of particles (N3: number of particles with an aerodynamic diameter higher than 3 nm, and N10: higher than 10 nm) concentrations at the high-altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010-2012. At MSC, PM10 (12 μg m-3) and N7 (2140 # cm-3) three-year arithmetic average concentrations were higher than those measured at other high-altitude sites in central Europe during the same period (PM10: 3-9 μg m-3 and N: 634-2070 # cm-3). By contrast, BC concentrations at MSC (0.2 μg m-3) were equal to or even lower than those measured at these European sites (0.2-0.4 μg m-3). These differences were attributed to the higher relevance of Saharan dust transport and to the higher importance of the biogenic precursor emissions and new particle formation (NPF) processes, and to the lower influence of anthropogenic emissions at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African air outbreaks (PM1&minus10: 13 μg m-3, PM1: 8 μg m-3 and BC: 0.3 μg m-3) and low concentrations when Atlantic advections occurred (PM1-10: 5 μg m-3, PM1: 4 μg m-3 and BC: 0.1 μg m-3). PM and BC concentrations increased in summer, with a secondary maximum in early spring, and were at their lowest in winter, due to the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter). The maximum in the warmer seasons was attributed to long-range transport processes that mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles, with maxima at midday in the

  12. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern~Pyrenees, 1570 m a.s.l.)

    Science.gov (United States)

    Ripoll, A.; Pey, J.; Minguillón, M. C.; Pérez, N.; Pandolfi, M.; Querol, X.; Alastuey, A.

    2013-10-01

    Time variation of mass particulate matter (PM1 and PM1-10), black carbon (BC) and particle number (N) concentrations at the high altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010-2012. The MSC site registered higher PM10 (12 μg m-3) and N > 7 nm (2209 # cm-3) concentrations than those measured at other high altitude sites in central Europe (PM10: 3-9 μg m-3 and N: 634-2070 # cm-3). By contrast, BC concentrations at MSC (0.2 μg m-3) were equal or even lower than those measured at these European sites (0.2-0.4 μg m-3). These differences were attributed to the lower influence of anthropogenic emissions and to the higher relevance of Saharan dust transport and new particle formation (NPF) processes at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African outbreaks (PM1-10: 13 μg m-3, PM1: 8 μg m-3 and BC: 0.3 μg m-3) and low concentrations when Atlantic advections occurred (PM1-10: 5 μg m-3, PM1: 4 μg m-3 and BC: 0.1 μg m-3). Because of the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter), PM and BC concentrations showed a marked increase in summer, with a secondary maximum in early spring, and were at their lowest during winter. The maximum in the warmer seasons was attributed to long-range transport processes which mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles with maxima at midday in the colder seasons. A statistically significant weekly variation was also obtained for the BC concentrations, displaying a progressive increase from Tuesday to Saturday, followed by a significant

  13. Admix Compatibility in Carbon Black Loaded Toners

    Institute of Scientific and Technical Information of China (English)

    Paul C. Julien

    2004-01-01

    In a xerographic system where the charge on the toner is controlled by the electrical nature of the carbon black used as a pigment, it is found that the speed with which added toner is charged to the proper level depends on the relative electrical negativity of the carbon black in the original and added toner. This is due to the fact that the incumbent toner typically shares its charge with the new toner through charge exchange among the conductive carbon black particles. If the carbon blacks are electrically dissimilar, this charge sharing may fail.Thus, a toner may work well by itself in a machine, but the same toner may fail when added to a machine already running with a toner from a different vendor or even a different lot of toner from the same vendor. Thus the electrical nature of the carbon black needs to be controlled. This can be done by controlling the oxidation of the carbon black.

  14. Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

    Directory of Open Access Journals (Sweden)

    S. Eckhardt

    2015-04-01

    Full Text Available The concentrations of sulfate, black carbon (BC and other aerosols in the Arctic are characterized by high values in late winter and spring (so-called Arctic Haze and low values in summer. Models have long been struggling to capture this seasonality and especially the high concentrations associated with Arctic Haze. In this study, we evaluate sulfate and BC concentrations from eleven different models driven with the same emission inventory against a comprehensive pan-Arctic measurement data set over a time period of two years (2008–2009. The set of models consisted of one Lagrangian particle dispersion model, four chemistry-transport models (CTMs, one atmospheric chemistry-weather forecast model and five chemistry-climate models (CCMs, of which two were nudged to meteorological analyses and three were running freely. The measurement data set consisted of surface measurements of equivalent BC (eBC from five stations (Alert, Barrow, Pallas, Tiksi and Zeppelin, elemental carbon (EC from Station Nord and Alert and aircraft measurements of refractory BC (rBC from six different campaigns. We find that the models generally captured the measured eBC/rBC and sulfate concentrations quite well, compared to past comparisons. However, the aerosol seasonality at the surface is still too weak in most models. Concentrations of eBC and sulfate averaged over three surface sites are underestimated in winter/spring in all but one model (model means for January-March underestimated by 59 and 37% for BC and sulfate, respectively, whereas concentrations in summer are overestimated in the model mean (by 88 and 44% for July–September, but with over- as well as underestimates present in individual models. The most pronounced eBC underestimates, not included in the above multi-site average, are found for the station Tiksi in Siberia where the measured annual mean eBC concentration is three times higher than the average annual mean for all other stations. This suggests

  15. Source attribution of black carbon in Arctic snow.

    Science.gov (United States)

    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.

  16. Long-term observations of black carbon mass concentrations at Fukue Island, western Japan, during 2009-2015: constraining wet removal rates and emission strengths from East Asia

    Science.gov (United States)

    Kanaya, Yugo; Pan, Xiaole; Miyakawa, Takuma; Komazaki, Yuichi; Taketani, Fumikazu; Uno, Itsushi; Kondo, Yutaka

    2016-08-01

    Long-term (2009-2015) observations of atmospheric black carbon (BC) mass concentrations were performed using a continuous soot-monitoring system (COSMOS) at Fukue Island, western Japan, to provide information on wet removal rate constraints and the emission strengths of important source regions in East Asia (China and others). The annual average mass concentration was 0.36 µg m-3, with distinct seasonality; high concentrations were recorded during autumn, winter, and spring and were caused by Asian continental outflows, which reached Fukue Island in 6-46 h. The observed data were categorized into two classes, i.e., with and without a wet removal effect, using the accumulated precipitation along a backward trajectory (APT) for the last 3 days as an index. Statistical analysis of the observed ΔBC / ΔCO ratios was performed to obtain information on the emission ratios (from data with zero APT only) and wet removal rates (including data with nonzero APTs). The estimated emission ratios (5.2-6.9 ng m-3 ppb-1) varied over the six air mass origin areas; the higher ratios for south-central East China (30-35° N) than for north-central East China (35-40° N) indicated the relative importance of domestic emissions and/or biomass burning sectors. The significantly higher BC / CO emission ratios adopted in the bottom-up Regional Emission inventory in Asia (REAS) version 2 (8.3-23 ng m-3 ppb-1) over central East China and Korea needed to be reduced at least by factors of 1.3 and 2.8 for central East China and Korea, respectively, but the ratio for Japan was reasonable. The wintertime enhancement of the BC emission from China, predicted by REAS2, was verified for air masses from south-central East China but not for those from north-central East China. Wet removal of BC was clearly identified as a decrease in the ΔBC / ΔCO ratio against APT. The transport efficiency (TE), defined as the ratio of the ΔBC / ΔCO ratio with precipitation to that without precipitation, was

  17. Black carbon and organic carbon emissions from wildfires in Mexico

    OpenAIRE

    XÓCHITL CRUZ NÚÑEZ; LOURDES VILLERS RUIZ; CARLOS GAY GARCÍA

    2014-01-01

    In Mexico, approximately 7650 wildfires occur annually, affecting 263 115 hectares of land. In addition to their impact on land degradation, wildfires cause deforestation, damage to ecosystems and promote land use change; apart from being the source of emissions of toxic substances to the environment (i.e., hydrogen cya - nide, black carbon and organic carbon). Black carbon is a short-lived greenhouse pollutant that also promotes snow and ice melting and decreased rainfall; it has an estimate...

  18. Dependence of climate forcing and response on the altitude of black carbon aerosols

    Science.gov (United States)

    Ban-Weiss, George A.; Cao, Long; Bala, G.; Caldeira, Ken

    2012-03-01

    Black carbon aerosols absorb solar radiation and decrease planetary albedo, and thus can contribute to climate warming. In this paper, the dependence of equilibrium climate response on the altitude of black carbon is explored using an atmospheric general circulation model coupled to a mixed layer ocean model. The simulations model aerosol direct and semi-direct effects, but not indirect effects. Aerosol concentrations are prescribed and not interactive. It is shown that climate response of black carbon is highly dependent on the altitude of the aerosol. As the altitude of black carbon increases, surface temperatures decrease; black carbon near the surface causes surface warming, whereas black carbon near the tropopause and in the stratosphere causes surface cooling. This cooling occurs despite increasing planetary absorption of sunlight (i.e. decreasing planetary albedo). We find that the trend in surface air temperature response versus the altitude of black carbon is consistent with our calculations of radiative forcing after the troposphere, stratosphere, and land surface have undergone rapid adjustment, calculated as "regressed" radiative forcing. The variation in climate response from black carbon at different altitudes occurs largely from different fast climate responses; temperature dependent feedbacks are not statistically distinguishable. Impacts of black carbon at various altitudes on the hydrological cycle are also discussed; black carbon in the lowest atmospheric layer increases precipitation despite reductions in solar radiation reaching the surface, whereas black carbon at higher altitudes decreases precipitation.

  19. Fracture resistance of rubbers with MWCNT, organoclay, silica and carbon black fillers as assessed by the J-integral: Effects of rubber type and filler concentration

    Directory of Open Access Journals (Sweden)

    T. Ricco

    2012-07-01

    Full Text Available The fracture resistance of different rubbers containing various nanofillers, such as multiwall carbon nanotube (MWCNT, organoclay, silica and carbon black (CB, was determined by the J-integral making use of the single edge notched tensile loaded (SEN-T single specimen approach. The elastomeric matrices were natural (NR, ethylene propylene diene (EPDM and hydrogenated nitrile rubbers (HNBR. Moreover, the strain softening (Payne effect of selected rubbers with 30 part per hundred rubber (phr filler content was also investigated by dynamic mechanical thermal analysis (DMTA in shear mode. DMTA results indicated that the Payne effect follows the ranking: MWCNT(fibrous > organoclay(platy > silica(spherical. J-resistance (JR curves were constructed by plotting the J value as a function of the crack tip opening displacement (CTOD*, monitored during loading. CTOD* = 0.1 mm was considered as crack initiation threshold and thus assigned to the critical value JIc. JIc increased with increasing filler loading, whereby MWCNT outperformed both silica and CB. On the other hand, JIc did not change with filler loading for the NR/organoclay systems that was traced to straininduced crystallization effect in NR. The tearing modulus (TJ also increased with increasing filler loading. The related increase strongly depended on both rubber and filler types. Nonetheless, the most prominent improvement in TJ among the fillers studied was noticed for the fibrous MWCNT.

  20. A strategy to achieve enhanced electromagnetic interference shielding at low concentration with a new generation of conductive carbon black in a chlorinated polyethylene elastomeric matrix.

    Science.gov (United States)

    Mondal, Subhadip; Ganguly, Sayan; Rahaman, Mostafizur; Aldalbahi, Ali; Chaki, Tapan K; Khastgir, Dipak; Das, Narayan Ch

    2016-09-21

    The fabrication of scalable and affordable conductive Ketjen carbon black (K-CB)-elastomer composites for adjustable electromagnetic interference (EMI) shielding remains a difficult challenge. Herein, chlorinated polyethylene (CPE)-K-CB composites have been developed by single step solution mixing to achieve high EMI shielding performance associated with absorption dominance potency by conductive dissipation as well as the reflection of electromagnetic waves. The dispersion of K-CB inside the CPE matrix has been corroborated by electron micrographs and atomic force microscopy (AFM). The K-CB filler and CPE polymer interaction has been investigated through the bound rubber content (Bdr) and the dynamic mechanical properties. The relatively low loading of K-CB with respect to other conventional carbon fillers contributes to a promising low percolation threshold (9.6 wt% K-CB) and a reasonably high EMI shielding effectiveness (EMI SE) value of 38.4 dB (at 30 wt% loading) in the X-band region (8.2 to 12.4 GHz). Classical percolation theory reveals that the electrical conduction behavior through the composite system is quasi-two dimensional in nature. Our belief lies in the promotion of scalable production of flexible and cost-effective K-CB-CPE composites of superior EMI SE to avoid electromagnetic radiation pollution.

  1. Black carbon in deep-Sea sediments

    Science.gov (United States)

    Masiello; Druffel

    1998-06-19

    Black carbon (BC) enters the ocean through aerosol and river deposition. BC makes up 12 to 31 percent of the sedimentary organic carbon (SOC) at two deep ocean sites, and it is 2400 to 13,900 carbon-14 years older than non-BC SOC deposited concurrently. BC is likely older because it is stored in an intermediate reservoir before sedimentary deposition. Possible intermediate pools are oceanic dissolved organic carbon (DOC) and terrestrial soils. If DOC is the intermediate reservoir, then BC is 4 to 22 percent of the DOC pool. If soils are the intermediate reservoir, then the importance of riverine carbon in the ocean carbon cycle has been underestimated.

  2. Exposure of pregnant mice to carbon black by intratracheal instillation

    DEFF Research Database (Denmark)

    Jackson, Petra; Hougaard, Karin S.; Vogel, Ulla;

    2011-01-01

    -induced response, such as inflammation during gestation, leads to secondary effects in the fetus. Time-mated C57BL/6BomTac mice were exposed by intratracheal instillation to vehicle (Nanopure water) or one of three concentrations (2.75, 13.5 or 67μg in 40μl Nanopure water) of carbon black Printex 90 (CB...

  3. Evaluation of black carbon estimations in global aerosol models

    NARCIS (Netherlands)

    Koch, D.; Schulz, M.; McNaughton, C.; Spackman, J.R.; Balkanski, Y.; Bauer, S.; Krol, M.C.

    2009-01-01

    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 concentr

  4. Simulations of phenol adsorption on activated carbon and carbon black

    OpenAIRE

    Prosenjak, Claudia; Valente Nabais, Joao; Laginhas, Carlos; Carrott, Peter; Carrott, Manuela

    2010-01-01

    We use grand canonical Monte Carlo and molecular dynamics simulations to study the adsorption of phenol on carbon materials. Activated carbon is modelled by pore size distributions based on DFT methods; carbon black is represented by a single carbon slab with varying percentages of surface atoms removed. GCMC results for the adsorption from the corresponding gas phase gave reasonable agreement with experimental adsorption results. MD simulations, that studied the influence of the presence of ...

  5. Pyrolytic carbon black composite and method of making the same

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Paranthaman, Mariappan Parans; Bi, Zhonghe

    2016-09-13

    A method of recovering carbon black includes the step of providing a carbonaceous source material containing carbon black. The carbonaceous source material is contacted with a sulfonation bath to produce a sulfonated material. The sulfonated material is pyrolyzed to produce a carbon black containing product comprising a glassy carbon matrix phase having carbon black dispersed therein. A method of making a battery electrode is also disclosed.

  6. Using measurements for evaluation of black carbon modeling

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2010-04-01

    Full Text Available The ever increasing use of air quality and climate model assessments to underpin economic, public health, and environmental policy decisions makes effective model evaluation critical. This paper discusses the properties of black carbon and light attenuation and absorption observations that are the key to a reliable evaluation of black carbon model and compares parametric and nonparametric statistical tools for the quantification of the agreement between models and observations. Black carbon concentrations are simulated with TM5/M7 global model from July 2002 to June 2003 at four remote sites (Alert, Jungfraujoch, Mace Head, and Trinidad Head and two regional background sites (Bondville and Ispra. Equivalent black carbon (EBC concentrations are calculated using light attenuation measurements from January 2000 to December 2005. Seasonal trends in the measurements are determined by fitting sinusoidal functions and the representativeness of the period simulated by the model is verified based on the scatter of the experimental values relative to the fit curves. When the resolution of the model grid is larger than 1°×1°, it is recommended to verify that the measurement site is representative of the grid cell. For this purpose, equivalent black carbon measurements at Alert, Bondville and Trinidad Head are compared to light absorption and elemental carbon measurements performed at different sites inside the same model grid cells. Comparison of these equivalent black carbon and elemental carbon measurements indicates that uncertainties in black carbon optical properties can compromise the comparison between model and observations. During model evaluation it is important to examine the extent to which a model is able to simulate the variability in the observations over different integration periods as this will help to identify the most appropriate timescales. The agreement between model and observation is accurately described by the overlap of

  7. Using measurements for evaluation of black carbon modeling

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2011-01-01

    Full Text Available The ever increasing use of air quality and climate model assessments to underpin economic, public health, and environmental policy decisions makes effective model evaluation critical. This paper discusses the properties of black carbon and light attenuation and absorption observations that are the key to a reliable evaluation of black carbon model and compares parametric and nonparametric statistical tools for the quantification of the agreement between models and observations. Black carbon concentrations are simulated with TM5/M7 global model from July 2002 to June 2003 at four remote sites (Alert, Jungfraujoch, Mace Head, and Trinidad Head and two regional background sites (Bondville and Ispra. Equivalent black carbon (EBC concentrations are calculated using light attenuation measurements from January 2000 to December 2005. Seasonal trends in the measurements are determined by fitting sinusoidal functions and the representativeness of the period simulated by the model is verified based on the scatter of the experimental values relative to the fit curves. When the resolution of the model grid is larger than 1° × 1°, it is recommended to verify that the measurement site is representative of the grid cell. For this purpose, equivalent black carbon measurements at Alert, Bondville and Trinidad Head are compared to light absorption and elemental carbon measurements performed at different sites inside the same model grid cells. Comparison of these equivalent black carbon and elemental carbon measurements indicates that uncertainties in black carbon optical properties can compromise the comparison between model and observations. During model evaluation it is important to examine the extent to which a model is able to simulate the variability in the observations over different integration periods as this will help to identify the most appropriate timescales. The agreement between model and observation is accurately described by the overlap of

  8. Worker exposure to ultrafine particles during carbon black treatment

    Directory of Open Access Journals (Sweden)

    Urszula Mikołajczyk

    2015-07-01

    Full Text Available Background: The aim of the project was to assess the exposure of workers to ultrafine particles released during handling and packing of carbon black. The assessment included the results of the measurements performed in a carbon black handling plant before, during, and after work shift. Material and Methods: The number concentration of particles within the dimension range 10–1000 nm and 10–100 nm was assayed by a condensation particle counter (CPC. The mass concentration of particles was determined by a DustTrak II DRX aerosol concentration monitor. The surface area concentration of the particles potentially deposited in the alveolar (A and tracheo-bronchial (TB regions was estimated by an AeroTrak 9000 nanoparticle monitor. Results: An average mass concentration of particles during the process was 6-fold higher than that before its start, while a 3-fold increase in the average number concentration of particles within the dimension range 10–1000 nm and 10–100 nm was observed during the process. At the same time a 4-fold increase was found in the surface area concentration of the particles potentially deposited in the A and TB regions. Conclusions: During the process of carbon black handling and packing a significantly higher values of each of the analysed parameters, characterizing the exposure to ultrafine particles, were noted. Med Pr 2015;66(3:317–326

  9. Black carbon, particle number concentration and nitrogen oxide emission factors of random in-use vehicles measured with the on-road chasing method

    Directory of Open Access Journals (Sweden)

    I. Ježek

    2015-06-01

    Full Text Available The chasing method was used in an on-road measurement campaign, and emission factors (EF of black carbon (BC, particle number (PN and nitrogen oxides (NOx were determined for 139 individual vehicles of different types encountered on the roads. The aggregated results provide EFs for BC, NOx and PN for three vehicle categories: goods vehicles, gasoline and diesel passenger cars. This is the first on-road measurement study where BC EFs of numerous individual diesel cars were determined in real-world driving conditions. We found good agreement between EFs of goods vehicles determined in this campaign and the results of previous studies that used either chasing or remote sensing measurement techniques. The composition of the sampled car fleet determined from the national vehicle registry information is reflective of Eurostat statistical data on the Slovenian and European vehicle fleet. The median BC EF of diesel and gasoline cars that were in use for less than 5 years, decreased by 60 and 47% from those in use for 5–10 years, respectively, the median NOx and PN EFs, of goods vehicles that were in use for less than five years, decreased from those in use for 5–10 years by 52 and 67%, respectively. The influence of engine maximum power of the measured EFs showed an increase in NOx EF from least to more powerful vehicles with diesel engines. Finally a disproportionate contribution of high emitters to the total emissions of the measured fleet was found; the top 25% of emitting diesel cars contributed 63, 47 and 61% of BC, NOx and PN emissions respectively. With the combination of relatively simple on-road measurements with sophisticated post processing individual vehicles EF can be determined and useful information about the fleet emissions can be obtained by exactly representing vehicles which contribute disproportionally to vehicle fleet emissions; and monitor how the numerous emission reduction approaches are reflected in on-road driving

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

    Science.gov (United States)

    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.

  11. Studies of activated carbon and carbon black for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Koetz, R.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Carbon Black and activated carbon materials providing high surface areas and a distinct pore distribution are prime materials for supercapacitor applications at frequencies < 0.5 Hz. A number of these materials were tested for their specific capacitance, surface and pore size distribution. High capacitance electrodes were manufactured on the laboratory scale with attention to ease of processability. (author) 1 fig., 1 ref.

  12. Black carbon in deep-sea sediments

    OpenAIRE

    1998-01-01

    Black carbon (BC) enters the ocean through aerosol and river deposition. BC makes up 12 to 31 percent of the sedimentary organic carbon (SOC) at two deep ocean sites, and it is 2400 to 13,900 carbon-14 years older than non-BC SOC deposited concurrently. BC is likely older because it is stored in an intermediate reservoir before sedimentary deposition. Possible intermediate pools are oceanic dissolved organic carbon (DOC) and terrestrial soils. If DOC is the intermediate reservoir, then BC is ...

  13. Are there "black holes" in carbonate deposystems?

    OpenAIRE

    Wright, V.P.; Cherns, L.

    2009-01-01

    The likelihood that extensive dissolution of aragonite (and high magnesian calcite) takes place during very early burial, even in relatively shallow tropical settings, has wide implications for interpreting and modelling ancient limestones. Some low energy environments may constitute net sinks (“black holes”) for carbonates. If this is the case attempts to model sediment budgets and develop depth-productivity profiles for carbonate systems require as yet unavailable quantitative data on the e...

  14. Modified carbon black materials for lithium-ion batteries

    Science.gov (United States)

    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.

  15. Black Carbon, The Pyrogenic Clay Mineral?

    Science.gov (United States)

    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...

  16. Opportunities and Challenges for Being a Carbon Black Great Power

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    1. The "Uth Five-year Plan" Lay- ing the Foundation for Carbon Black Great Power 1.1 Rapid growth of carbon black output and production capacity During the "llth Five-year Plan" Period, China carbon black output was increased by 1.1 times and realized doubling; and the production capacity of carbon black realized an average annu- al growth of 16.9%. In 2011, the carbon black output was 3.853 million tons, increased by 14.2% compared with that of the last year, and the pro- portion of carbon black output in the world carbon black output was increased from 16% to 36%. The carbon black production capacity was 5.345 mil- lion tons, increased by 6% compared with that of the last year, and the proportion of carbon black production capacity in the world carbon black out- put reached 38%. Chinese carbon black output has been ranking the 1st place throughout the world for 6 years successively, and China has become a great power of carbon black production in the world.

  17. Black carbon: The reverse of its dark side

    NARCIS (Netherlands)

    Koelmans, A.A.; Jonker, M.T.O.; Cornelissen, G.; Bucheli, T.D.; Noort, van P.C.M.; Gustafsson, O.

    2006-01-01

    The emission of black carbon is known to cause major environmental problems. Black carbon particles contribute to global warming, carry carcinogenic compounds and cause serious health risks. Here, we show another side of the coin. We review evidence that black carbon may strongly reduce the risk pos

  18. Cycling of black carbon in the ocean

    OpenAIRE

    2016-01-01

    Black carbon (BC) is a byproduct of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial timescales in the world oceans has remained unknown. Here, we quantified dissolved BC (DBC) in marine dissolved organic carbon (DOC) isolated by solid phase extraction (SPE) 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 ...

  19. Influence of sample composition on aerosol organic and black carbon determinations

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Corrigan, C.E.

    1995-07-01

    In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550{degrees}C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Tate [Baylor Univ., Waco, TX (United States)

    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.

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

    Science.gov (United States)

    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.

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

    DEFF Research Database (Denmark)

    Edmondson, Jill L.; Stott, Iain; Potter, Jonathan;

    2015-01-01

    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...... 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....

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

    Energy Technology Data Exchange (ETDEWEB)

    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).

  4. Influence of black tea concentrate on kombucha fermentation

    Directory of Open Access Journals (Sweden)

    Malbaša Radomir V.

    2006-01-01

    Full Text Available Kombucha is cultivated on substrates prepared with different concentrations of black tea and substrate obtained by diluting a substrate with highest concentration of black tea with cold tap water. Qualify of produced beverages is compared with the beverage obtained in traditional fermentation of 1.5 g/L of black tea, sweetened with 70 g/L of sucrose. Inoculation was performed with 10% (v/v of fermentation liquid from previous process, and the fermentation was carried out at 28°C under aerobic conditions, for ten days. Process of fermentation was monitored by following pH, total acids. D-gluconic acid and caffeine content. Beverages obtained in fermentation with diluted black tea concentrate had similar amounts of investigated metabolites compared with traditional one. Use of diluted black tea concentrate as a substrate needs the shorter time for the substrate preparation, which significantly saves energy.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  7. Is marine dissolved organic matter the "missing sink" for soil-derived black carbon?

    Science.gov (United States)

    Dittmar, Thorsten; Suryaputra, I. Gusti N. A.; Niggemann, Jutta

    2010-05-01

    The thermal alteration of biomass during wildfires can be an important factor for the stabilization of organic matter in soils. Black carbon, i.e. biochars and soot, is more resistant to biodegradation than unaltered biomass, and it can therefore accumulate in soils and sediments. Our knowledge on the turnover of black carbon is still very fragmentary, and the known loss rates do not account for the estimated production rates. Major loss mechanisms remain unidentified or have been underestimated. Recently, we have identified a major thermogenic component in dissolved organic matter (DOM) of the deep ocean. We hypothesize that black carbon in soils is solubilized over time, probably via microbial interaction, and transported via rivers into the ocean. DOM, one of the largest organic carbon pools on earth, could therefore be an important transport medium of soil-derived black carbon. A case study was performed in the Suwannee River estuary and adjacent oceanic shelf (Florida, USA). The Suwannee River drains extensive wetlands and fire-impacted forests. The fate of dissolved black carbon was traced from the river through its estuary into the open Gulf of Mexico. Black carbon was molecularly quantified as benzenepolycarboxylic acids after nitric acid oxidation via a new UPLC method (ultra-performance liquid chromatography). The molecular analysis was accompanied by optical (excitation-emission matrix fluorescence and absorbance spectroscopy) and elemental characterization of DOM. A major component (approx. 10% on a carbon basis) of Suwannee River DOM could be identified as black carbon. The concentration of black carbon decreased offshore, and on the open ocean only about 1% of DOM could be identified as black carbon. In the deep ocean, the thermogenic component of DOM is higher and approx. 2.4% of DOM. The surface ocean must therefore be an efficient sink for dissolved black carbon. We hypothesize that sunlight may initiate photochemical reactions that cause a loss of

  8. Sources of uncertainties in modelling Black Carbon at the global scale

    Directory of Open Access Journals (Sweden)

    F. Cavalli

    2009-11-01

    Full Text Available Our understanding of the global black carbon cycle is essentially qualitative due to uncertainties in our knowledge of the properties of black carbon. This work investigates uncertainties related to modelling black carbon: due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and due to the uncertainties in the definition and quantification of observed black carbon, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering black carbon as bulk aerosol and a simple treatment in the removal and (ii a more complete description of microphysical aging within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol. In the first approach a fixed 70% of black carbon is scavenged in clouds and removed when rain is present. The second leads to a global average of 40% black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, showing that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude.

  9. CCN activation of pure and coated carbon black particles.

    Science.gov (United States)

    Dusek, U; Reischl, G P; Hitzenberger, R

    2006-02-15

    The CCN (cloud condensation nucleus) activation of pure and coated carbon black particles was investigated using the University of Vienna cloud condensation nuclei counter (Giebl, H.; Berner, A.; Reischl, G.; Puxbaum, H.; Kasper-Giebl, A.; Hitzenberger, R. J. Aerosol Sci. 2002, 33, 1623-1634). The particles were produced by nebulizing an aqueous suspension of carbon black in a Collison atomizer. The activation of pure carbon black particles was found to require higher supersaturations than predicted by calculations representing the particles as insoluble, wettable spheres with mobility equivalent diameter. To test whether this effect is an artifact due to heating of the light-absorbing carbon black particles in the laser beam, experiments at different laser powers were conducted. No systematic dependence of the activation of pure carbon black particles on laser power was observed. The observations could be modeled using spherical particles and an effective contact angle of 4-6 degrees of water at their surface. The addition of a small amount of NaCl to the carbon black particles (by adding 5% by mass NaCl to the carbon black suspension) greatly enhanced their CCN efficiency. The measured CCN efficiencies were consistent with Kohler theory for particles consisting of insoluble and hygroscopic material. However, coating the carbon black particles with hexadecanol (a typical film-forming compound with one hydrophobic and one hydrophilic end) efficiently suppressed the CCN activation of the carbon black particles.

  10. Prenatal Exposure to Carbon Black (Printex 90)

    DEFF Research Database (Denmark)

    Jackson, Petra; Vogel, Ulla; Wallin, Håkan;

    2011-01-01

    Maternal pulmonary exposure to ultrafine particles during pregnancy may affect the health of the child. Developmental toxicity of carbon black (Printex 90) nanoparticles was evaluated in a mouse model. Time-mated mice were intratracheally instilled with Printex 90 dispersed in Millipore water on ...... on gestation days (GD) 7, 10, 15 and 18, with total doses of 11, 54 and 268 mu g Printex 90/animal. The female offspring prenatally exposed to 268 mu g Printex 90/animal displayed altered habituation pattern during the Open field test....

  11. Supply Deficit of Feedstock Oils for Carbon Black

    Institute of Scientific and Technical Information of China (English)

    Li Bingyan

    2007-01-01

    @@ Feedstock oils used for carbon blackproduction mainly include ethylene tar,anthracene oil and coal tar. With thegrowing output of carbon black in re-cent years, demand for feedstock oilshas increased constantly.

  12. Sedimentary records of black carbon in the sea area of the Nansha Islands since the last glaciation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Core 17962 taken from the sea area of the Nansha Islands recorded a sedimentary history of more than 30 000 years. The black carbon data from the core, which can inform us of the history of vegetation fires, show that during the last glaciation, especially during the last glacial maximum at about 18 kaBP, the fluctuation of the concentration and accumulation rate of the black carbon was relatively great, whereas it was small during the Holocene. The isotope composition of the black carbon indicates that the precursors of black carbon were mainly grasses from the last glaciation to the Holocene. The sub-alpine and alpine vegetation zones covered mainly with grass and bush on the lands around the southern South China Sea were probably the sources of black carbon. The altitudinal vegetation changes from the last glaciation to the Holocene gave rise to the changes of the sedimentary characteristics of black carbon.

  13. Effect of sterilization on mineralization of straw and black carbon

    DEFF Research Database (Denmark)

    Bobul'ská, Lenka; Bruun, Sander; Fazekašová, Danica

    2013-01-01

    The study was aimed at investigating the role of microorganisms in the degradation of BC (black carbon). CO evolution was measured under sterilized and non-sterilized soil using BC and straw amendments. Black carbon and straw were produced from homogenously C labelled roots of barley (Hordeum vul...... abiotic source must also be present perhaps abiotic mineralization of labile BC components....

  14. Black Carbon in Marine Dissolved Organic Carbon: Abundance and Radiocarbon Measurements in the Global Ocean

    Science.gov (United States)

    Coppola, A. I.; Walker, B. D.; Druffel, E. R. M.

    2014-12-01

    Compound specific radiocarbon analysis is a powerful tool for understanding the cycling of individual components, such as black carbon (BC) produced from biomass burning and fossil fuel combustion, within bulk pools, like the marine dissolved organic carbon pool. Here, we use a solid phase extraction method and a wide range of solvent polarities to concentrate dissolved organic carbon from seawater. Then we isolate BC in sufficient quantities for radiocarbon analysis. We report the radiocarbon age of BC, concentrations and its relative structure, from coastal and open ocean surface samples. We will discuss our progress towards measuring these quantities in dissolved organic carbon collected from the Pacific and Atlantic oceans to understand the fate, transformation and cycling of BC in the world ocean. These measurements are paired with bulk DOC Δ14C profiles, providing insight into the role of BC as a missing sink in the ultra-refractory DOC pool.

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

    Science.gov (United States)

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

    2011-07-18

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract 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.

  18. Cycling of black carbon in the ocean

    Science.gov (United States)

    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.

  19. Estimation and prediction of black carbon emissions in Beijing City

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan; SHAO Min

    2007-01-01

    Black carbon is a by-product of incomplete combustion of carbon containing fuels. It can alter atmospheric radiation property and make adverse impacts on human health. The energy consumption in Beijing City depends largely on coal burning. Recently, Beijing City has been performing the municipal energy structure adjustment as a tool for air pollution abatement, aiming at the air quality goal for the Beijing 2008 Olympic Games. Based on Beijing energy use data in 2000, combined with emission factors of major sources of black carbon, the emission of black carbon in Beijing City is estimated to be 7.77 Gg. Coke, raw coal and biomass as non-commercial energy are the main contributors to municipal black carbon emissions. Based on Beijing energy planning in the year 2008, the emission of black carbon in 2008 will be 2.97 Gg if the contribution from biomass is not taken into account. Assuming that the black carbon emission from rural biomass in 2008 is the same as that in 2004, the biomass burning will be the largest emitter of black carbon to Beijing City in 2008.

  20. Preparation and application of active gangue's carbon black

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang-lin; ZHANG Yi-dong

    2007-01-01

    After three-stage pulverization, dry-distillated activation and coupling agent surface modification, the kaolinite-typed gangue of Sichuan Hongni Coal Mine(SHCM) can be manufactured into activated gangue's carbon black. Its surface area is >25 m2/g, and possesses carbon black's carbon framework and structure. It can be used as strengthening agent of high polymer material such as rubber.

  1. Addressing inconsistencies in black carbon literature

    Science.gov (United States)

    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

  2. Sources of uncertainties in modelling black carbon at the global scale

    Directory of Open Access Journals (Sweden)

    E. Vignati

    2010-03-01

    Full Text Available Our understanding of the global black carbon (BC cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation.

    The schemes for the atmospheric processing of black carbon that have been tested with the model are (i a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of

  3. Sources of uncertainties in modelling black carbon at the global scale

    Science.gov (United States)

    Vignati, E.; Karl, M.; Krol, M.; Wilson, J.; Stier, P.; Cavalli, F.

    2010-03-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the measurements used for the model evaluation. The schemes for the atmospheric processing of black carbon that have been tested with the model are (i) a simple approach considering BC as bulk aerosol and a simple treatment of the removal with fixed 70% of in-cloud black carbon concentrations scavenged by clouds and removed when rain is present and (ii) a more complete description of microphysical ageing within an aerosol dynamics model, where removal is coupled to the microphysical properties of the aerosol, which results in a global average of 40% in-cloud black carbon that is scavenged in clouds and subsequently removed by rain, thus resulting in a longer atmospheric lifetime. This difference is reflected in comparisons between both sets of modelled results and the measurements. Close to the sources, both anthropogenic and vegetation fire source regions, the model results do not differ significantly, indicating that the emissions are the prevailing mechanism determining the concentrations and the choice of the aerosol scheme does not influence the levels. In more remote areas such as oceanic and polar regions the differences can be orders of magnitude, due to the differences between the two schemes. The more complete description reproduces the seasonal trend of the black carbon observations in those areas, although not always the magnitude of the signal, while the more simplified approach underestimates black carbon concentrations by orders of magnitude. The sensitivity to wet

  4. Global emission inventory and atmospheric transport of black carbon. Evaluation of the associated exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rong

    2015-06-01

    This thesis presents research focusing on the improvement of high-resolution global black carbon (BC) emission inventory and application in assessing the population exposure to ambient BC. A particular focus of the thesis is on the construction of a high-resolution (both spatial and sectorial) fuel consumption database, which is used to develop the emission inventory of black carbon. Above all, the author updates the global emission inventory of black carbon, a resource subsequently used to study the atmospheric transport of black carbon over Asia with the help of a high-resolution nested model. The thesis demonstrates that spatial bias in fuel consumption and BC emissions can be reduced by means of the sub-national disaggregation approach. Using the inventory and nested model, ambient BC concentrations can be better validated against observations. Lastly, it provides a complete uncertainty analysis of global black carbon emissions, and this uncertainty is taken into account in the atmospheric modeling, helping to better understand the role of black carbon in regional and global air pollution.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Z. Shen

    2014-01-01

    Full Text Available 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

  7. The uptake of ethyl iodide on black carbon surface

    Institute of Scientific and Technical Information of China (English)

    YIN Shi; WANG WeiGang; GE MaoFa

    2008-01-01

    The importance of the iodine chemistry in the atmosphere has been demonstrated by recent observations. The uptake of ethyl iodine on black carbon surface was investigated at 298 K for the first time. Degussa FW2 (an amorphous black carbon comprising medium oxides) was used as black carbon sample. Black carbon surface was found to be deactivated in reaction with C2H5I, and the uptake coefficient (γ) was dependent on the time of exposure. The value of (2.3±0.9)×10-2 was determined for the initial uptake coefficient (γ0). The result suggests that the heterogeneous loss of C2H5I on carbonaceous aerosols may be important under the atmospheric conditions.

  8. Global civil aviation black carbon emissions.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2013-12-01

    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(θ)]˜ (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 significant

  10. Effects of Surface-modification of Carbon Black on the Characteristics of Polymerized Toner

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ho; Kim, Dae Su [Chungbuk National University, Cheongju (Korea, Republic of)

    2013-10-15

    Carbon black was surface-modified to prepare styrene-based suspension polymerized toner with excellent carbon black dispersibility inside toner particles. Carbon black was oxidized first to introduce hydroxyl groups on the surfaces, then esterification between the hydroxyl groups and carboxyl groups of organic acids (oleic acid, palmitic acid, acrylic acid) was followed to obtain organically surface-modified carbon black. The surface-modification of carbon black was confirmed by FTIR. Apparent carbon black dispersibility in the monomer mixture of the binder resin was tested and the particle size of dispersed carbon black was measured by particle size analyzer. Optical micrographs showed that carbon black dispersibility inside toner particles was improved considerably when the carbon black surface-modified with oleic acid was used. The polymerized toner prepared with the carbon black surface-modified with oleic acid showed ideal particle size and size distribution as a toner.

  11. Comparative DEMS study on the electrochemical oxidation of carbon blacks

    DEFF Research Database (Denmark)

    Ashton, Sean James; Arenz, Matthias

    2012-01-01

    heat-treated between 2100 and 3200 °C, such as those typically used as corrosion resistant carbon (CRC) supports for polymer electrolyte membrane fuel cell (PEMFC) catalysts. A methodology combining cyclic voltammetry (CV) and differential electrochemical mass spectrometry (DEMS) is used, which allows...... the characterisation and comparison of the complete electrochemical oxidation rates and behaviours of the various carbon blacks. It is observed that the behaviour of the carbon black towards electrochemical oxidation is highly dynamic, and dependent on the properties of the pristine carbon back, the degree...

  12. Black carbon radiative forcing at TOA decreased during aging

    Science.gov (United States)

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan; Chen, Hao

    2016-12-01

    During aging processing, black carbon (also called soot) particles may tend to be mixed with other aerosols, and highly influence their radiative forcing. In this study, freshly emitted soot particles were simulated as fractal aggregates composed of small spherical primary monomers. After aging in the atmosphere, soot monomers were coated by a thinly layer of sulfate as thinly coated soot particles. These soot particles were entirely embedded into large sulfate particle by further aging, and becoming heavily coated soot particles. In clear-sky conditions, black carbon radiative forcing with different aging states were investigated for the bottom and top of atmosphere (BOA and TOA). The simulations showed that black carbon radiative forcing increased at BOA and decreased at TOA after their aging processes. Thinly and heavily coated states increased up to ~12% and ~35% black carbon radiative forcing at BOA, and black carbon radiative forcing at TOA can reach to ~20% and ~100% smaller for thinly and heavily coated states than those of freshly emitted states, respectively. The effect of aging states of black carbon radiative forcing was varied with surface albedo, aerosol optical depth and solar zenith angles. These findings would be helpful for the assessments of climate change.

  13. Adsorption of Remazol Black B dye on Activated Carbon Felt

    Directory of Open Access Journals (Sweden)

    Donnaperna Lucio

    2008-11-01

    Full Text Available The adsorption of Remazol Black B (anionic dye on a microporous activated carbon felt is investigated from its aqueous solution. The surface chemistry of activated carbon is studied using X-ray microanalysis, "Boehm" titrations and pH of PZC measurements which indicates that the surface oxygenated groups are mainly acidic in nature. The kinetics of Remazol Black B adsorption is observed to be pH dependent and governed by the diffusion of the dye molecules. The experimental data can be explained by "intra-particle diffusion model". For Remazol Black B, the Khan model is best suited to simulate the adsorption isotherms.

  14. Artificial black opal fabricated from nanoporous carbon spheres.

    Science.gov (United States)

    Yamada, Yuri; Ishii, Masahiko; Nakamura, Tadashi; Yano, Kazuhisa

    2010-06-15

    A nanocasting method via chemical vapor deposition of acetonitrile was successfully employed to fabricate porous carbon colloidal crystal using colloidal crystal from monodispersed mesoporous silica spheres (MMSS) as a sacrificial scaffold. The mesostructure as well as periodic arrays within (111) plane of MMSS were replicated for the carbon colloidal crystal (black opal) with the length scale in the centimeter range. Brilliant iridescent colors were clearly observed for the first time on the black carbon colloidal crystal fabricated from porous carbon spheres, and they changed dramatically in accordance with the observation angle, like natural black opals. Reflection spectra measurements based on 2D surface diffraction and Bragg diffraction in the mirror mode were conducted for the fabricated carbon periodic arrays. The periodicity in the (111) plane as well as in the direction perpendicular to the (111) plane of the colloidal crystal was evaluated by comparing the results obtained from these two measurements. It was found that the periodicity in the direction perpendicular to the (111) surface is not high for the obtained black carbon opal. On the other hand, the relationship between the incident angles and the peak wavelengths of the reflection spectra, collected in the condition where the incident light and the reflected light pass through in the same direction, is governed by an approximation based on 2D surface diffraction. The results imply that the origin of the iridescent colors on the fabricated black carbon opal is derived from the periodicity not in the direction perpendicular to the (111) plane but within the (111) plane.

  15. Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2006-01-01

    Full Text Available Although the definition and measurement techniques for atmospheric 'black carbon' ('BC' or 'elemental carbon'' ('EC' have long been subjects of scientific controversy, the recent discovery of light-absorbing carbon that is not black ('brown carbon, Cbrown' makes it imperative to reassess and redefine the components that make up light-absorbing carbonaceous matter (LAC in the atmosphere. Evidence for the atmospheric presence of Cbrown comes from (1 spectral aerosol light absorption measurements near specific combustion sources, (2 observations of spectral properties of water extracts of continental aerosol, (3 laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and (4 indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that brown carbon may severely bias measurements of 'BC' and 'EC' over vast parts of the troposphere, especially those strongly polluted by biomass burning, where the mass concentration of Cbrown is high relative to that of soot carbon. Chemical measurements to determine 'EC' are biased by the refractory nature of Cbrown as well as by complex matrix interferences. Optical measurements of 'BC' suffer from a number of problems: (1 many of the presently used instruments introduce a substantial bias into the determination of aerosol light absorption, (2 there is no unique conversion factor between light absorption and 'EC' or 'BC' concentration in ambient aerosols, and (3 the difference in spectral properties between the different types of LAC, as well as the chemical complexity of Cbrown, lead to several conceptual as well as practical complications. We also suggest that due to the sharply increasing absorption of Cbrown towards the UV, single-wavelength light absorption measurements may not be adequate for the assessment of absorption of solar radiation in the troposphere. We discuss the possible consequences of these effects for our

  16. Temporal variations of black carbon during haze and non-haze days in Beijing.

    Science.gov (United States)

    Liu, Qingyang; Ma, Tangming; Olson, Michael R; Liu, Yanju; Zhang, Tingting; Wu, Yu; Schauer, James J

    2016-09-16

    Black carbon (BC) aerosol has been identified as one of key factors responsible for air quality in Beijing. BC emissions abatement could help slow regional climate change while providing benefits for public health. In order to quantify its variations and contribution to air pollution, we systematically studied real-time measurements of equivalent black carbon (eBC) in PM2.5 aerosols at an urban site in Beijing from 2010 to 2014. Equivalent black carbon (eBC) is used instead of black carbon (BC) for data derived from Aethalometer-31 measurement. Equivalent BC concentrations showed significant temporal variations with seasonal mean concentration varying between 2.13 and 5.97 μg m(-3). The highest concentrations of eBC were found during autumn and winter, and the lowest concentrations occurred in spring. We assessed the temporal variations of eBC concentration during haze days versus non-haze days and found significantly lower eBC fractions in PM2.5 on haze days compared to those on non-haze days. Finally, we observed a clear inverse relationship between eBC and wind speed. Our results show that wind disperses PM2.5 more efficiently than eBC; so, secondary aerosols are not formed to the same degree as primary aerosols over the same transport distance during windy conditions.

  17. Temporal variations of black carbon during haze and non-haze days in Beijing

    Science.gov (United States)

    Liu, Qingyang; Ma, Tangming; Olson, Michael R.; Liu, Yanju; Zhang, Tingting; Wu, Yu; Schauer, James J.

    2016-09-01

    Black carbon (BC) aerosol has been identified as one of key factors responsible for air quality in Beijing. BC emissions abatement could help slow regional climate change while providing benefits for public health. In order to quantify its variations and contribution to air pollution, we systematically studied real-time measurements of equivalent black carbon (eBC) in PM2.5 aerosols at an urban site in Beijing from 2010 to 2014. Equivalent black carbon (eBC) is used instead of black carbon (BC) for data derived from Aethalometer-31 measurement. Equivalent BC concentrations showed significant temporal variations with seasonal mean concentration varying between 2.13 and 5.97 μg m‑3. The highest concentrations of eBC were found during autumn and winter, and the lowest concentrations occurred in spring. We assessed the temporal variations of eBC concentration during haze days versus non-haze days and found significantly lower eBC fractions in PM2.5 on haze days compared to those on non-haze days. Finally, we observed a clear inverse relationship between eBC and wind speed. Our results show that wind disperses PM2.5 more efficiently than eBC; so, secondary aerosols are not formed to the same degree as primary aerosols over the same transport distance during windy conditions.

  18. Black carbon aerosol-induced Northern Hemisphere tropical expansion

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  20. Photo-lability of deep ocean dissolved black carbon

    Directory of Open Access Journals (Sweden)

    A. Stubbins

    2012-01-01

    Full Text Available 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.

  1. An Important Supplement to NAA in Study on Atmosphere Pollution:Determination of Black Carbon

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Light absorption in the atmosphere is dominated by elemental carbon (EC), sometimes called black carbon (BC). Black carbon is an important indication of man-made pollution in airborne particulate matter

  2. Commuter exposure to black carbon, carbon monoxide, and noise in the mass transport khlong boats of Bangkok, Thailand

    Science.gov (United States)

    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.

  3. Black Carbon Trends over Several Decades at Multiple Locations

    Science.gov (United States)

    Preble, C. V.; Hadley, O. L.; Bond, T. C.; Kirchstetter, T.

    2012-12-01

    Archived air quality data in the U.S. and Europe can be used to reconstruct past trends in black carbon (BC), an indicator of fossil fuel combustion and biomass burning. Here, we consider coefficient of haze (COH) data that was extensively measured in California, New Jersey, and other North American locations from the mid-1960s to the turn of the century. We reinstated COH monitors alongside aethalometers in Vallejo and San Jose, California, and after two years of air monitoring determined that COH is proportional to and, thus, can be used to infer past concentrations of BC. Analyzing COH data sets, we found that BC concentrations markedly decreased from 1965 to 2000 in both California and New Jersey. The opposing trend of increasing energy consumption over the same period indicates successful regulatory control of sources and a shift from dirtier to cleaner fuels. As air quality improved over four decades, a seasonal trend of maximum BC concentrations in winter persisted in California but, somewhat surprisingly, disappeared in New Jersey. A strong weekly cycle of lowest BC concentrations on weekends was evident in California and New Jersey, suggesting that diesel traffic, which exhibits a similar weekly cycle, has been a major source of BC in both states. Our extended analysis will include BC trends in other regions of North America and Europe and will be applied to understand BC radiative forcing in California and deposition of pollutants in the Arctic.

  4. Nanohybrid TiO2/carbon black sensor for NO2 gas

    Institute of Scientific and Technical Information of China (English)

    Wei-Jen Liou; Hong-Ming Lin

    2007-01-01

    A nanohybrid sensor of nanosized TiO2-coated carbon black particles, prepared by sol-gel technology for the detection of NO2 gas, has been developed. The response of the electric resistance of the hybrid sensor to NO2 concentration is investigated, showing that the sensitivity of the hybrid sensor is raised as certain ratio of the TiO2 content in the sensor. Easy and cheap to fabricate, the hybrid TiO2/carbon black promises to be a practical sensor for detecting NO2 gas.

  5. Electric anisotropy in high density polyethylene + carbon black composites induced by mechanical deformation

    Energy Technology Data Exchange (ETDEWEB)

    Vigueras-Santiago, E; Hernandez-Lopez, S; Camacho-Lopez, M A; Lara-Sanjuan, O, E-mail: eviguerass@uaemex.m [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA), Facultad de Quimica, UAEM. Paseo Colon esq. con Paseo Tollocan, s/n. C.P. 50000, Toluca (Mexico)

    2009-05-01

    High density polyethylene + carbon black composites with electrical anisotropy was studied. Electrical anisotropy was induced by uniaxial mechanical deformation and injection moulding. We show that anisotropy depends on the carbon black concentration and percentage deformation. Resistivity had the highest anisotropy resistivity around the percolation threshold. Perpendicular resistivity showed two magnitude orders higher than parallel resistivity for injected samples, whereas resistivity showed an inverse behaviour for 100% tensile samples. Both directions were set respect to the deformation axe. Anisotropy could be explained in terms of the molecular deformation (alignment) of the polymer chains as a response of the deformation process originating a redistribution of the carbon black particles in both directions. Alignment of the polymer chains was evidenced by polarized Raman spectroscopy.

  6. Photo-lability of deep ocean dissolved black carbon

    Science.gov (United States)

    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

  7. Photo-lability of deep ocean dissolved black carbon

    Directory of Open Access Journals (Sweden)

    A. Stubbins

    2012-05-01

    Full Text Available 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

  8. MORPHOLOGY OF BLACK CARBON AEROSOLS AND UBIQUITY OF 50-NANOMETER BLACK CARBON AEROSOLS IN THE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    Fengfu Fu; Liangjun Xu; Wei Ye; Yiquan Chen; Mingyu Jiang; Xueqin Xu

    2006-01-01

    Different-sized aerosols were collected by an Andersen air sampler to observe the detailed morphology of the black carbon (BC) aerosols which were separated chemically from the other accompanying aerosols, using a Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer (SEM-EDX). The results indicate that most BC aerosols are spherical particles of about 50 nm in diameter and with a homogeneous surface. Results also show that these particles aggregate with other aerosols or with themselves to form larger agglomerates in the micrometer range. The shape of these 50-nm BC spherical particles was found to be very similar to that of BC particles released from petroleum-powered vehicular internal combustion engines. These spherical BC particles were shown to be different from the previously reported fullerenes found using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS).

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

    Science.gov (United States)

    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

  10. Siberian Arctic black carbon sources constrained by model and observation

    Science.gov (United States)

    Winiger, Patrik; Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

    2017-02-01

    Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ngṡm‑3 to 302 ngṡm‑3) and dual-isotope–constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth.

  11. Fluxes of soot black carbon to South Atlantic sediments

    Science.gov (United States)

    Lohmann, Rainer; Bollinger, Kevyn; Cantwell, Mark; Feichter, Johann; Fischer-Bruns, Irene; Zabel, Matthias

    2009-03-01

    Deep sea sediment samples from the South Atlantic Ocean were analyzed for soot black carbon (BC), total organic carbon (TOC), stable carbon isotope ratios (δ13C), and polycyclic aromatic hydrocarbons (PAHs). Soot BC was present at low concentrations (0.04-0.17% dry weight), but accounted for 3-35% of TOC. Fluxes of soot BC were calculated on the basis of known sedimentation rates and ranged from 0.5 to 7.8 μg cm-2 a-1, with higher fluxes near Africa compared to South America. Values of δ13C indicated a marine origin for the organic carbon but terrestrial sources for the soot BC. PAH ratios implied a pyrogenic origin for most samples and possibly a predominance of traffic emissions over wood burning off the African coast. A coupled ocean-atmosphere-aerosol-climate model was used to determine fluxes of BC from 1860 to 2000 to the South Atlantic. Model simulation and measurements both yielded higher soot BC fluxes off the African coast and lower fluxes off the South American coast; however, measured sedimentary soot BC fluxes exceeded simulated values by ˜1 μg cm-2 a-1 on average (within a factor of 2-4). For the sediments off the African coast, soot BC delivery from the Congo River could possibly explain the higher flux rates, but no elevated soot BC fluxes were detected in the Amazon River basin. In total, fluxes of soot BC to the South Atlantic were ˜480-700 Gg a-1 in deep sea sediments. Our results suggest that attempts to construct a global mass balance of BC should include estimates of the atmospheric deposition of BC.

  12. Black Carbon Flux Across the Himalaya through the Kali Gandaki Valley in Nepal

    Science.gov (United States)

    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.

  13. Fluvial organic carbon losses from a Bornean black water river

    OpenAIRE

    2010-01-01

    The transport of carbon from terrestrial ecosystems such as peatlands into rivers and out to the oceans plays an important role in the carbon cycle because it provides a link between the terrestrial and marine carbon cycles. Concentrations of dissolved organic carbon (DOC) and particulate organic carbon (POC) were analysed from the source to the mouth of the River Sebangau in Central Kalimantan, Indonesia during the dry and wet seasons in 2008/2009 and an annual total organic carbon (TOC) flu...

  14. Dissolved Black Carbon in the South China Sea

    Science.gov (United States)

    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.

  15. Solid phase extraction method for the study of black carbon cycling in dissolved organic carbon using radiocarbon

    OpenAIRE

    2015-01-01

    © 2015 Elsevier B.V.. Radiocarbon analysis is a powerful tool for understanding the cycling of individual components within carbon pools, such as black carbon (BC) in dissolved organic carbon (DOC). Radiocarbon (δ14C) measurements of BC in DOC provide insight into one source of aged, recalcitrant DOC. We report a modified solid phase extraction (SPE) method to concentrate 43±6% of DOC (SPE-DOC) from seawater. We used the Benzene Polycarboxylic Acid (BPCA) method to isolate BC from SPE-DOC (SP...

  16. 20 years of Black Carbon measurements in Germany

    Science.gov (United States)

    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

  17. Elementary concentration of Peruibe black mud by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Torrecilha, Jefferson K.; Ponciano, Ricardo; Silva, Paulo S.C da, E-mail: jeffkoy@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The Peruibe Black Mud is used in therapies such as psoriasis, peripheral dermatitis, acne, seborrehea, myalgia arthritis and rheumatic non-articular processes. This material is characterized by is fine organic matter particles, sulphate reducing bacteria and a high content of potential reduction ions. Although this material is particles, sulphate reducing bacteria and a high content of potential reduction ions. Although this material is considered natural, it may not be free of possible adverse health effects, like toxic chemical elements, when used for therapeutic purposes. In the therapeutic treatments involving clays, clays are used in mud form also called peloids, obtained by maturation process. Five in natura and three maturated Black Mud samples were collected in Peruibe city, Sao Paulo State, Brazil. To investigate the distribution of major, trace and rare earth elements in the in natura and maturated clays that constitute the Peruibe Black Mud, neutron activation analysis (NAA) was used. A comparison between in natura and maturated mud shows that major, trace and rare earth elements follow the same order in both types. Generally, the concentrations in the maturated mud are slightly lower than in natura mud. Enrichment on the upper continental crust could be observed for the elements As, Br, Sb and Se, in these types of mud. (author)

  18. Radiocarbon Studies of Black Carbon in the Marine Environment

    OpenAIRE

    2015-01-01

    The incomplete combustion of biomass and fossil fuels produces black carbon (BC). BC is recalcitrant and serves as a long term holding pool for carbon, with a mean residence time of one to two orders of magnitude greater than unburnt carbon on land. Yet the known sources of BC are far larger than the known sinks, which led to studies of BC in the ocean’s dissolved organic carbon (DOC) reservoir. The goal of this dissertation was to measure the abundance and residence times of BC in sedime...

  19. Factors controlling seasonal variations in Arctic black carbon

    Science.gov (United States)

    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.

  20. Costs and global impacts of black carbon abatement strategies

    OpenAIRE

    K. Rypdal; Rive, N.; T. K. Berntsen; Z. Klimont; Mideksa, T.K.; G. Myhre; R. B. Skeie

    2009-01-01

    Abatement of particulate matter has traditionally been driven by health concerns rather than its role in global warming. Here we assess future abatement strategies in terms of how much they reduce the climate impact of black carbon (BC) and organic carbon (OC) from contained combustion. We develop global scenarios which take into account regional differences in climate impact, costs of abatement and ability to pay, as well as both the direct and indirect (snow-albedo) climate impact of BC ...

  1. Molecular simulation of polycyclic aromatic hydrocarbon sorption to black carbon

    NARCIS (Netherlands)

    Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

    2009-01-01

    Strong sorption of hydrophobic organic contaminants to soot or black carbon (BC) is an important environmental process limiting the bioremediation potential of contaminated soils and sediments. Reliable methods to predict BC sorption coefficients for organic contaminants are therefore required. A co

  2. Potential impacts of black carbon on the marine microbial community

    NARCIS (Netherlands)

    Malits, A.; Cattaneo, R.; Sintes, E.; Gasol, J.M.; Herndl, G.J.; Weinbauer, M.G.

    2015-01-01

    Black carbon (BC) is the carbonaceous residue of the incomplete combustion of fossil fuels and biomass and encompasses a range of chemically heterogeneous substances from partly charred plant material to highly condensed soot aerosols. We addressed the potential role of BC aerosol deposition on mari

  3. Black silicon maskless templates for carbon nanotube forests

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal; Schmidt, Michael Stenbæk; Boisen, Anja

    2013-01-01

    We present here a proof of concept for a novel fabrication method of vertically aligned carbon nanotube forests, utilizing black silicon nanograss (a forest of silicon nanometer-sized spikes created with reactive ion etching) coated with titanium tungsten diffusion barrier as a template. The meth...

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

    Science.gov (United States)

    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.

  5. Seasonal and diurnal variations of black carbon and organic carbon aerosols in Bangkok

    Science.gov (United States)

    Sahu, L. K.; Kondo, Y.; Miyazaki, Y.; Pongkiatkul, Prapat; Kim Oanh, N. T.

    2011-08-01

    Measurements of black carbon (BC) and organic carbon (OC) were conducted in Bangkok during 2007-2008. Annual trends of BC and OC show strong seasonality with lower and higher concentrations during wet and dry seasons, respectively. Flow of cleaner air, wet removal, and negligible biomass burning resulted in the lowest concentrations of aerosols in the wet season. In addition to anthropogenic sources, long-range transport and biomass burning caused higher concentrations in the dry and hot seasons, respectively. Despite extensive biomass burning in the hot season, moderate levels of aerosols were due to the mixing with air masses from the Pacific Ocean. Diurnal distributions exhibit peaks during rush hour marked by minima in the OC/BC ratio and stagnant wind flow. The lowest concentrations in the afternoon hours could be due to deeper planetary boundary layer and reduced traffic. Overall, the concentrations of both BC and OC decrease with the increase in wind speed. The weekend effects, due to reduced emission during weekends, in the concentrations of both BC and OC were significant. Therefore, stricter abatement in vehicular emissions could substantially reduce pollution. A slope of ΔBC/ΔCO of 9.8 ngm-3 ppbv-1 for the wet season represents the emission ratio from vehicular sources. The highest of ΔOC/ΔBC (3 μg μg-1) in the hot season was due to the predominant influence of biomass burning and significant formation of secondary OC. The levels of BC and OC in Bangkok fall within the ranges of their concentrations measured in the major cities of East Asia.

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

    Science.gov (United States)

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

    2015-04-01

    During two flight campaigns: around the world (2012) and over the Arctic (2013) we demonstrated the feasibility of scientific research and aerial measurements of aerosolized Black Carbon with ultra-light aircraft. Conducted measurements provided first ever information on Black Carbon concentrations and sources over such a large area at altitude. Ground-level measurements of atmospheric aerosols are routinely performed around the world, but there exists very little data on their vertical and geographical distribution in the global atmosphere. These 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. Light absorbing carbonaceous aerosols and black carbon (BC) in particular are a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. A single-seat ultra-light aircraft flew around the world and on a Arctic expedition. The flights 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 [1, 2]. We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas. 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 and we estimate the underestimation of the direct forcing by models assuming a simple linear relationship between BC concentration and forcing in comparison to observations [3,4]. 1. , Carbon Sampling Takes Flight, Science 2012, 335, 1286. 2. G. Močnik, L. Drinovec, M

  7. Black Carbon in Seasonal Snow across Northern Xinjiang, Northwestern China

    Science.gov (United States)

    Ye, H.; Zhang, R.; Shi, J.; Huang, J.; Warren, S. G.; Fu, Q.

    2012-12-01

    Black carbon (BC) particles in snow can significantly reduce the snow albedo and enhance the absorption of solar radiation, with important impacts on climate and the hydrological cycle. A field campaign was carried out to measure the BC content in seasonal snow in Qinghai and Xinjiang provinces of western China, in January and February, 2012. About 300 snow samples were collected at 38 sites, 6 in Qinghai and 32 in Xinjiang. The observational results at the sites in Xinjiang, where the dominant absorbing impurities in snow are BC particles, are reported in this paper. The BC mass-fractions in seasonal snow across northern Xinjiang have a median value of ~70 ng/g, lower than those in northeast China but comparable to those in snow on glaciers of the Tianshan Mountains. The estimated concentration of BC at the cleanest site in Xinjiang is 20 ng/g, which is similar to that found along the coast of the Arctic Ocean. In general, the BC content of snow decreases with altitude. The data from this field campaign should be useful for testing transport models and climate models for the simulated BC in snow.

  8. Characterization of Black Carbon Mixing State Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Davidovits, P. [Boston College, Chestnut Hill, MA (United States); Lewis, E. R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Onasch, T. B. [Aerodyne Research, Billerica, MA (United States)

    2016-04-01

    Interpreting the temporal relationship between the scattering and incandescence signals recorded by the Single Particle Soot Photometer (SP2), Sedlacek et al. (2012) reported that 60% of the refractory black carbon containing particles in a plume containing biomass burning tracers exhibited non-core-shell structure. Because the relationship between the rBC (refractory black carbon) incandescence and the scattering signals had not been reported in the peer-reviewed literature, and to further evaluate the initial interpretation by Sedlacek et al., a series of experiments was undertaken to investigate black carbon-containing particles of known morphology using Regal black (RB), a proxy for collapsed soot, as the light-absorbing substance to characterize this signal relationship. Particles were formed by coagulation of RB with either a solid substance (sodium chloride or ammonium sulfate) or a liquid substance (dioctyl sebacate), and by condensation with dioctyl sebacate, the latter experiment forming particles in a core-shell configuration. Each particle type experienced fragmentation (observed as negative lagtimes), and each yielded similar lagtime responses in some instances, confounding attempts to differentiate particle morphology using current SP2 lagtime analysis. SP2 operating conditions, specifically laser power and sample flow rate, which in turn affect the particle heating and dissipation rates, play an important role in the behavior of particles in the SP2, including probability of fragmentation. This behavior also depended on the morphology of the particles and on the thermochemical properties of the non-RB substance. Although these influences cannot currently be unambiguously separated, the SP2 analysis may still provide useful information on particle mixing states and black carbon particle sources. This work was communicated in a 2015 publication (Sedlacek et al. 2015)

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

    Directory of Open Access Journals (Sweden)

    Z. L. Wang

    2014-12-01

    Full Text Available 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.

  10. Phase Transformations of Graphite and Carbon Black by Laser with Low Power Density

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structure phase transformations of graphite and carbon black induced by pulsed laser were studied in this paper. Under irradiation with laser beam of 1.06μm wavelength and power density of 106 W· cm- 2, both graphite structure and carbon black structure were changed obviously. The results of Raman analyses and Transmission Electron Microscopy (TEM) observations show that graphite transforms into nanodiamond about 5 nm and carbon black is graphitized. It is demonstrated that graphite is the intermediate phase in the transformation from carbon black to diamond, and graphite is easier to transform into diamond by laser irradiation than carbon black.

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

    Directory of Open Access Journals (Sweden)

    K. Hammes

    2008-02-01

    Full Text Available 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. We use soils sampled 100 years apart in a Russian steppe preserve to generate the first whole-profile estimate of BC stocks and turnover in the field. BC stocks (initially 2.5 kg m-2 decreased 25% with cessation of biomass burning. BC turnover in the soil was 293 y (best estimate; range 212–541 y, much faster than inert/passive carbon in soil models. Such results provide a new constraint on theories of soil carbon stabilization. Most importantly, BC cannot be assumed chemically recalcitrant in all soils; other explanations for very old soil carbon are needed.

  12. Evaluation of black carbon estimations in global aerosol models

    Directory of Open Access Journals (Sweden)

    Y. Zhao

    2009-11-01

    Full Text Available 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 retrievals from AERONET and Ozone Monitoring Instrument (OMI 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 0.7 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 8 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 ratio is 0.4 and models 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

  13. Evaluation of black carbon estimations in global aerosol models

    Directory of Open Access Journals (Sweden)

    D. Koch

    2009-07-01

    Full Text Available 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 Ozone Monitoring Instrument (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 50 N, 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 underestimates 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

  14. Evaluation of Black Carbon Estimations in Global Aerosol Models

    Energy Technology Data Exchange (ETDEWEB)

    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

  15. Black carbon from the Mississippi River: quantities, sources, and potential implications for the global carbon cycle.

    Science.gov (United States)

    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.

  16. Study on Microwave Dielectric Property of Carbon Black and Short Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    WU Hong-huan; ZHU Dong-mei; LUO Fa; ZHOU Wan-cheng; WANG Xiao-yan

    2006-01-01

    Carbon black and carbon fibers of different lengths were introduced in different matrices at different ratios to explore their microwave dielectric properties under 8.2 GHz-12.4 GHz. It is found that the actual dielectric constants of the samples containing carbon black are in a two-order function of the contents of carbon black ((з)′,(з)″=Av2+Bv+C) and the complex dielectric constants show an obvious frequency response. Of the added fibers of different lengths, the 4 mm-long one could well disperse in the matrices having not only good frequency response, but also larger real parts, imaginary parts and loss values. The imaginary parts and the loss values (tanδ) of the samples with 4 mm-long carbon fibers added increase linearly with the contents of fiber increasing. So it is practicable to adjust the dielectric parameters of the material in a wide range by changing the added amount of carbon black, and the carbon fiber or altering the lengths of the carbon fiber added.

  17. Aerosol light absorption, black carbon, and elemental carbon at the Fresno Supersite, California

    Science.gov (United States)

    Chow, Judith C.; Watson, John G.; Doraiswamy, Prakash; Chen, Lung-Wen Antony; Sodeman, David A.; Lowenthal, Douglas H.; Park, Kihong; Arnott, W. Patrick; Motallebi, Nehzat

    2009-08-01

    Particle light absorption ( bap), black carbon (BC), and elemental carbon (EC) measurements at the Fresno Supersite during the summer of 2005 were compared to examine the equivalency of current techniques, evaluate filter-based bap correction methods, and determine the EC mass absorption efficiency (σ ap) and the spectral dependence of bap. The photoacoustic analyzer (PA) was used as a benchmark for in-situ bap. Most bap measurement techniques were well correlated ( r ≥ 0.95). Unadjusted Aethalometer (AE) and Particle Soot Absorption Photometer (PSAP) bap were up to seven times higher than PA bap at similar wavelengths because of absorption enhancement by backscattering and multiple scattering. Applying published algorithms to correct for these effects reduced the differences to 24 and 17% for the AE and PSAP, respectively, at 532 nm. The Multi-Angle Absorption Photometer (MAAP), which accounts for backscattering effects, overestimated bap relative to the PA by 51%. BC concentrations determined by the AE, MAAP, and Sunset Laboratory semi-continuous carbon analyzer were also highly correlated ( r ≥ 0.93) but differed by up to 57%. EC measured with the IMPROVE/STN thermal/optical protocols, and the French two-step thermal protocol agreed to within 29%. Absorption efficiencies determined from PA bap and EC measured with different analytical protocols averaged 7.9 ± 1.5, 5.4 ± 1.1, and 2.8 ± 0.6 m 2/g at 532, 670, and 1047 nm, respectively. The Angström exponent (α) determined from adjusted AE and PA bap ranged from 1.19 to 1.46. The largest values of α occurred during the afternoon hours when the organic fraction of total carbon was highest. Significant biases associated with filter-based measurements of bap, BC, and EC are method-specific. Correcting for these biases must take into account differences in aerosol concentration, composition, and sources.

  18. Electromagnetic properties of carbon black and barium titanate composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang Guiqin [School of Material Science and Engineering, Dalian University of Technology, Dalian 116023 (China)], E-mail: c2b2chen@163.com; Chen Xiaodong; Duan Yuping; Liu Shunhua [School of Material Science and Engineering, Dalian University of Technology, Dalian 116023 (China)

    2008-04-24

    Nanocrystalline carbon black/barium titanate compound particle (CP) was synthesized by sol-gel method. The phase structure and morphology of compound particle were investigated by X-ray diffraction (XRD), transmission electron microscope (TEM) and Raman spectrum measurements, the electroconductivity was test by trielectrode arrangement and the precursor powder was followed by differential scanning calorimetric measurements (DSC) and thermal gravimetric analysis (TGA). In addition, the complex relative permittivity and permeability of compound particle were investigated by reflection method. The compound particle/epoxide resin composite (CP/EP) with different contents of CP were measured. The results show barium titanate crystal is tetragonal phase and its grain is oval shape with 80-100 nm which was coated by carbon black film. As electromagnetic (EM) complex permittivity, permeability and reflection loss (RL) shown that the compound particle is mainly a kind of electric and dielectric lossy materials and exhibits excellent microwave absorption performance in the X- and Ku-bands.

  19. Oxidation behavior of a kind of carbon black

    Institute of Scientific and Technical Information of China (English)

    TANG JunShi; SONG Qiang; HE BaiLei; YAO Qiang

    2009-01-01

    The DTG curves of a kind of carbon black during TPO tests were found to have multiple peaks with an unusual sharp peak after the main peak. TPO tests with different sample loads, oxygen fractions and heating rates were carried out to study the influence of the experimental parameters on the sharp peak. The results show that the sharp peak is not caused by heat and mass transfer limitations, but by the intrinsic oxidation kinetics of the carbon black. The evolution of the specific surface area during the intrinsic kinetic controlled oxidation process was then analyzed using isothermal oxidation at low temperatures which showed that the sharp peak is caused by the increase of the specific surface area. The pore structure changes greatly influence the oxidation process when the reaction is controlled by the intrinsic kinetics. When there were no heat and mass transfer limitations, the different oxidation processes result in the same specific surface area evolution.

  20. Evaluation of the genetic activity of industrially produced carbon black.

    Science.gov (United States)

    Kirwin, C J; LeBlanc, J V; Thomas, W C; Haworth, S R; Kirby, P E; Thilagar, A; Bowman, J T; Brusick, D J

    1981-06-01

    Commercially produced oil furnace carbon black (Chemical Abstract Service Registry No. 1333-86-4) has been evaluated by five different assay for genetic activity. These were the Ames Salmonella typhimurium reverse mutation test, sister chromatid exchange test in CHO cells, mouse lymphoma test, cell transformation assay in C3H/10T1/2 cells, and assay for genetic effects in Drosophila melanogaster. Limited cellular toxicity was exhibited but no significant genetic activity was noted.

  1. Black carbon mixing state impacts on cloud microphysical properties: effects of aerosol plume and environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Ping Pui; Riemer, Nicole; West, Matthew

    2016-05-27

    Black carbon (BC) is usually mixed with other aerosol species within individual aerosol particles. This mixture, along with the particles' size and morphology, determines the particles' optical and cloud condensation nuclei properties, and hence black carbon's climate impacts. In this study the particle-resolved aerosol model PartMC-MOSAIC was used to quantify the importance of black carbon mixing state for predicting cloud microphysical quantities. Based on a set of about 100 cloud parcel simulations a process level analysis framework was developed to attribute the response in cloud microphysical properties to changes in the underlying aerosol population ("plume effect") and the cloud parcel cooling rate ("parcel effect"). It shows that the response of cloud droplet number concentration to changes in BC emissions depends on the BC mixing state. When the aerosol population contains mainly aged BC particles an increase in BC emission results in increasing cloud droplet number concentrations ("additive effect"). In contrast, when the aerosol population contains mainly fresh BC particles they act as sinks for condensable gaseous species, resulting in a decrease in cloud droplet number concentration as BC emissions are increased ("competition effect"). Additionally, we quantified the error in cloud microphysical quantities when neglecting the information on BC mixing state, which is often done in aerosol models. The errors ranged from -12% to +45% for the cloud droplet number fraction, from 0% to +1022% for the nucleation-scavenged black carbon (BC) mass fraction, from -12% to +4% for the effective radius, and from -30% to +60% for the relative dispersion.

  2. Adsorption ability of the carbon black for nickel ions uptake from aqueous solution

    OpenAIRE

    Rađenović Ankica; Malina Jadranka

    2013-01-01

    Surface modification can be performed by adsorption of certain organic compounds on the surface of carbon. The main objective of this work was to compare the adsorption ability of acid-modified carbon black with the non-modified one. Modification process was performed by adsorption of acetic acid onto commercial carbon black surface. A batch adsorption system was applied to study the both adsorption reaction, acetic acid and Ni(II) adsorption onto the carbon black. Adsorption isotherms ...

  3. Black-carbon absorption enhancement in the atmosphere determined by particle mixing state

    Science.gov (United States)

    Liu, Dantong; Whitehead, James; Alfarra, M. Rami; Reyes-Villegas, Ernesto; Spracklen, Dominick V.; Reddington, Carly L.; Kong, Shaofei; Williams, Paul I.; Ting, Yu-Chieh; Haslett, Sophie; Taylor, Jonathan W.; Flynn, Michael J.; Morgan, William T.; McFiggans, Gordon; Coe, Hugh; Allan, James D.

    2017-02-01

    Atmospheric black carbon makes an important but poorly quantified contribution to the warming of the global atmosphere. Laboratory and modelling studies have shown that the addition of non-black-carbon materials to black-carbon particles may enhance the particles’ light absorption by 50 to 60% by refracting and reflecting light. Real-world experimental evidence for this `lensing’ effect is scant and conflicting, showing that absorption enhancements can be less than 5% or as large as 140%. Here we present simultaneous quantifications of the composition and optical properties of individual atmospheric black-carbon particles. We show that particles with a mass ratio of non-black carbon to black carbon of less than 1.5, which is typical of fresh traffic sources, are best represented as having no absorption enhancement. In contrast, black-carbon particles with a ratio greater than 3, which is typical of biomass-burning emissions, are best described assuming optical lensing leading to an absorption enhancement. We introduce a generalized hybrid model approach for estimating scattering and absorption enhancements based on laboratory and atmospheric observations. We conclude that the occurrence of the absorption enhancement of black-carbon particles is determined by the particles’ mass ratio of non-black carbon to black carbon.

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

    Science.gov (United States)

    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

  5. Aerosol organic carbon to black carbon ratios: Analysis ofpublished data and implications for climate forcing

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Factors Controlling Black Carbon Deposition in Snow in the Arctic

    Science.gov (United States)

    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

  7. Aerosol black carbon at five background measurement sites over Finland, a gateway to the Arctic

    Science.gov (United States)

    Hyvärinen, A.-P.; Kolmonen, P.; Kerminen, V.-M.; Virkkula, A.; Leskinen, A.; Komppula, M.; Hatakka, J.; Burkhart, J.; Stohl, A.; Aalto, P.; Kulmala, M.; Lehtinen, K. E. J.; Viisanen, Y.; Lihavainen, H.

    2011-08-01

    Aerosol equivalent black carbon (BC e) was measured at five different background stations in Finland, with the longest data set from Hyytiälä, December 2004-December 2008. Measurements were conducted either with an aethalometer or a Multi-Angle Absorption Photometer, MAAP. Measured black carbon concentrations were highest in Virolahti in southeastern Finland, with annual averages ranging from 385 to 460 ng m -3, followed by Hyytiälä (250-370 ng m -3), Utö (230-270 ng m -3), Puijo (225-230 ng m -3), and Pallastunturi (60-70 ng m -3) in northern Finland. The BC e fractions of measured PM 2.5 concentrations were generally between 5 and 10%, with highest fractions at Virolahti close to the Eastern border. At all the stations, the highest concentrations were observed during the spring and the winter, and the lowest concentrations during the summer. The seasonal cycle could generally be attributed to the reaching of long-range-transported black carbon. Additional reasons were increasing domestic wood burning and reduced boundary-layer height during winter, and a more effective vertical mixing during summer. The highest concentrations for each station occurred with southerly winds, and on the basis of trajectory analyses, the source areas of BC e resided mostly in Central and Eastern Europe. Occasionally the long-range-transported BC e concentrations were elevated for short periods to fulfill the characteristics of pollution episodes. From these episodes, about 62% were a result of non-fire anthropogenic sources and 36% due to open biomass burning sources. Episodes from the biomass burning sources were most often observed during the spring.

  8. Thermal Analysis Characterization of Elastomers and Carbon Black Filled Rubber Composites for Army Applications

    Science.gov (United States)

    1985-06-01

    Organ~ce, 60.40 % Carbon Black, 36.15 450(S) 2 Carbon black, 36.40 500 % Residue, 2.09 410(SH) 2 Residue, 3.20 22 2 Organica , 64.99 2 Organics, 62.97 2...64.92 1 Organics, 62.30 I Carbon Black, 31.42 395(S) I Carbon Black, 34.02 420 Z Residue, 3.66 440(SR) 1 Reuidue, 3.69 73 - C I Organica , 6’.33 470... Organica , 62.80 % Organics, 62.80 % Carbon black, 36.27 470(S) 2 Carbon black, It.60 505 2 Residue, 0.963 435(51) 2 Residue, 1.60 Iii 2 Organics

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Measured black carbon deposition on the Sierra Nevada snow pack and implication for snow pack retreat

    Directory of Open Access Journals (Sweden)

    O. L. Hadley

    2010-04-01

    Full Text Available Modeling studies show that the darkening of snow and ice by black carbon (BC deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition on the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  12. Measured black carbon deposition on the Sierra Nevada snow pack and implication for snow pack retreat

    Directory of Open Access Journals (Sweden)

    O. L. Hadley

    2010-08-01

    Full Text Available Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  13. Measured Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow Pack Retreat

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-12

    Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  14. Mesozoic black shales, source mixing and carbon isotopes

    Science.gov (United States)

    Suan, Guillaume

    2016-04-01

    Over the last decades, considerable attention has been devoted to the paleoenvironmental and biogeochemical significance of Mesozoic black shales. Black shale-bearing successions indeed often display marked changes in the organic carbon isotope composition (δ13Corg), which have been commonly interpreted as evidence for dramatic perturbations of global carbon budgets and CO2 levels. Arguably the majority of these studies have discarded some more "local" explanations when interpreting δ13Corg profiles, most often because comparable profiles occur on geographically large and distant areas. Based on newly acquired data and selected examples from the literature, I will show that the changing contribution of organic components with distinct δ13C signatures exerts a major but overlooked influence of Mesozoic δ13Corg profiles. Such a bias occurs across a wide spectrum of sedimentological settings and ages, as shown by the good correlation between δ13Corg values and proxies of kerogen proportions (such as rock-eval, biomarker, palynofacies and palynological data) recorded in Mesozoic marginal to deep marine successions of Triassic, Jurassic and Cretaceous age. In most of these successions, labile, 12C-enriched amorphous organic matter of marine origin dominates strata deposited under anoxic conditions, while oxidation-resistant, 13C-rich terrestrial particles dominate strata deposited under well-oxygenated conditions. This influence is further illustrated by weathering profiles of Toarcian (Lower Jurassic) black shales from France, where weathered areas dominated by refractory organic matter show dramatic 13C-enrichment (and decreased total organic carbon and pyrite contents) compared to non-weathered portions of the same horizon. The implications of these results for chemostratigraphic correlations and pCO2 reconstructions of Mesozoic will be discussed, as well as strategies to overcome this major bias.

  15. World Carbon Black Output to Reach 12.7 Million Tons in 2015

    Institute of Scientific and Technical Information of China (English)

    Zhu Yongkang

    2012-01-01

    From April 13 to April 17, "Carbon Black China of 2012" (CBC2012) was held in Hangzhou, China. Mr. Paul Ita, the president of US marketing research institution Notch Consulting Group, announced that the prospect of carbon black industry was closely linked with the development of auto industry and tire industry. The demand for carbon black of 2010 increased by 15% compared with that of 2009; the growth rate of demand for carbon black was 5.8% in 2011 and the total output was 10.7 million tons, which increased by about 5.5% compared with that of 2010.

  16. Observations of Black Carbon and Aerosol Optical Depth in the Kali Gandaki Valley, Nepal

    Science.gov (United States)

    Dhungel, S.; Panday, A. K.; Mahata, K. S.

    2012-12-01

    During recent years there has been increasing concern about the deposition of black carbon from the Indo-Gangetic Plains onto the glaciers and snowfields of the Tibetan Plateau. There has also been increasing concern about the rapid increase in air temperature at high altitudes over the Tibetan Plateau and the Himalaya. To date, there is very little knowledge about the transport pathways for pollutants traveling from the Indo-Gangetic Plains across the Himalaya to the Tibetan Plateau. 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 South Asia 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.). 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. Observations of BC and aerosol optical depth (AOD) from Aeronet are analyzed and presented. Diurnal and seasonal patterns of BC have been observed with higher values during the day and lower at night and also highest during pre-monsoon and lowest during monsoon season, with observed BC concentrations exceeding 5 μg while average concentration around 3.7 μg.

  17. Climate effects of black carbon aerosols in China and India.

    Science.gov (United States)

    Menon, Surabi; Hansen, James; Nazarenko, Larissa; Luo, Yunfeng

    2002-09-27

    In recent decades, there has been a tendency toward increased summer floods in south China, increased drought in north China, and moderate cooling in China and India while most of the world has been warming. We used a global climate model to investigate possible aerosol contributions to these trends. We found precipitation and temperature changes in the model that were comparable to those observed if the aerosols included a large proportion of absorbing black carbon ("soot"), similar to observed amounts. Absorbing aerosols heat the air, alter regional atmospheric stability and vertical motions, and affect the large-scale circulation and hydrologic cycle with significant regional climate effects.

  18. Recommendations for the interpretation of "black carbon" measurements

    Directory of Open Access Journals (Sweden)

    A. Petzold

    2013-04-01

    Full Text Available Although black carbon (BC is one of the key atmospheric particulate components driving climate change and air quality, there is no agreement on the terminology that considers all aspects of specific properties, definitions, measurement methods, and related uncertainties. As a result, there is much ambiguity in the scientific literature of measurements and numerical models that refer to BC with different names and based on different properties of the particles, with no clear definition of the terms. The authors present here a recommended terminology to clarify the terms used for BC in atmospheric research, with the goal of establishing unambiguous links between terms, targeted material properties and associated measurement techniques.

  19. Modal character of atmospheric black carbon size distributions

    Science.gov (United States)

    Berner, A.; Sidla, S.; Galambos, Z.; Kruisz, C.; Hitzenberger, R.; ten Brink, H. M.; Kos, G. P. A.

    1996-08-01

    Samples of atmospheric aerosols, collected with cascade impactors in the urban area of Vienna (Austria) and at a coastal site on the North Sea, were investigated for black carbon (BC) as the main component of absorbing material and for mass. The size distributions are structured. The BC distributions of these samples show a predominant mode, the accumulation aerosol, in the upper submicron size range, a less distinct finer mode attributable to fresh emissions from combustion sources, and a distinct coarse mode of unclear origin. It is important to note that some parameters of the accumulation aerosol are related statistically, indicating the evolution of the atmospheric accumulation aerosol.

  20. Catalytic Enhancement of Carbon Black and Coal-Fueled Hybrid Direct Carbon Fuel Cells

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2015-01-01

    was investigated using current-voltage-power density curves. In the anode chamber, catalysts are mixed with the carbon-carbonate mixture. These catalysts include various manganese oxides (MnO2, Mn2O3, Mn3O4, MnO), metal carbonates (Ag2CO3, MnCO3, Ce2(CO3)3), metals (Ag, Ce, Ni), doped-ceria (CeO2, Ce1-xGdxO2-x/2......, Ce1-xREExO2-δ (REE = Pr, Sm)) and metal oxides (LiMn2O4, Ag2O). Materials showing the highest activity in carbon black (Mn2O3, CeO2, Ce0.6Pr0.4O2-δ, Ag2O) were subsequently tested for catalytic activity toward bituminous coal, as revealed by both I-V-P curves and electrochemical impedance......Hybrid direct carbon fuel cells (HDCFCs) consisting of a solid carbon (carbon black)-molten carbonate ((62–38 wt% Li-K)2CO3) mixtures in the anode chamber of an anode-supported solid oxide fuel cell type full-cell are tested for their electrochemical performance between 700 and 800°C. Performance...

  1. Adsorption Behavior of Black Carbon for Radioactive Iodine Species in Subsurface Environments

    Science.gov (United States)

    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.

  2. A photochemically resistant component in riverine dissolved black carbon

    Science.gov (United States)

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Birchwood feedstock was used to make slow pyrolysis biochar that contained 89% carbon and rubber. Composites made from blended fillers of 25/75 biochar/carbon black were equivalent to or superior to their 100% carbo...

  5. Oxidation behavior of a kind of carbon black

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The DTG curves of a kind of carbon black during TPO tests were found to have multiple peaks with an unusual sharp peak after the main peak.TPO tests with different sample loads,oxygen fractions and heating rates were carried out to study the influence of the experimental parameters on the sharp peak.The results show that the sharp peak is not caused by heat and mass transfer limitations,but by the intrinsic oxidation kinetics of the carbon black.The evolution of the specific surface area during the intrinsic kinetic controlled oxidation process was then analyzed using isothermal oxidation at low temperatures which showed that the sharp peak is caused by the increase of the specific surface area.The pore structure changes greatly influence the oxidation process when the reaction is controlled by the intrinsic kinetics.When there were no heat and mass transfer limitations,the different oxidation processes result in the same specific surface area evolution.

  6. Fibrinogen concentration and its role in CVD risk in black South Africans - effect of urbanisation

    NARCIS (Netherlands)

    Pieters, Marlien; De Maat, Moniek P. M.; Jerling, Johann C.; Hoekstra, Tiny; Kruger, Annamarie

    2011-01-01

    The aim of this study was to investigate correlates of fibrinogen concentration in black South Africans, as well as its association with cardiovascular disease (CVD) risk and whether urbanisation influences this association. A total of 1,006 rural and 1,004 urban black South Africans from the PURE s

  7. Changing Export of Dissolved Black Carbon from Arctic Rivers

    Science.gov (United States)

    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.

  8. Black carbon and carbon monoxide over Bay of Bengal during W_ICARB: Source characteristics

    Science.gov (United States)

    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.

  9. Effect of carbon black on the properties of irradiated recycled polyamide/rubber waste composites

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Medhat M., E-mail: medhat_smh@yahoo.co [National Center for Radiation Research and Technology, Nasr City, Cairo 11731 (Egypt); Badway, Nagwa A.; Gamal, Azza M. [Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo (Egypt); Elnaggar, Mona Y.; Hegazy, El-Sayed A. [National Center for Radiation Research and Technology, Nasr City, Cairo 11731 (Egypt)

    2010-08-15

    In the present study, the synergistic effect of carbon black (CB) content % and gamma irradiation on some mechanical, thermal, chemical stability and micro-structural properties of the moulded waste polyamide copolymer/recycled waste rubber powder (rPA/WRP) 50/50 was investigated. The ternary composites of CB concentrations, 6, 12, 18, and 24 wt.%, were irradiated with doses of 50, 100, 150 and 200 kGy. The composites mechanical properties: tensile strength, elongation at break, and hardness, and the thermal properties: melting temperature (T{sub m}) and ({Delta}H) were measured. Also, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), swelling and chemical stability were investigated.

  10. Sources of uncertainties in modelling black carbon at the global scale

    NARCIS (Netherlands)

    Vignati, E.; Karl, M.; Krol, M.C.; Wilson, J.; Stier, P.; Cavalli, F.

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in th

  11. Plasma Polymerization Surface Modification of Carbon Black and its Effect in Elastomers

    NARCIS (Netherlands)

    Mathew, T.; Datta, R.N.; Dierkes, W.K.; Talma, A.G.; Ooij, van W.J.; Noordermeer, J.W.M.

    2011-01-01

    Surface modification of carbon black by plasma polymerization was aimed to reduce its surface energy in order to compatibilize the filler with various elastomers. A fullerenic carbon black was used for the modification process. Thermogravimetric analysis, wetting behavior with liquids of known surfa

  12. Carbon black nanoparticle instillation induces sustained inflammation and genotoxicity in mouse lung and liver

    DEFF Research Database (Denmark)

    Bourdon, Julie A; Saber, Anne T; Jacobsen, Nicklas R;

    2012-01-01

    Widespread occupational exposure to carbon black nanoparticles (CBNPs) raises concerns over their safety. CBNPs are genotoxic in vitro but less is known about their genotoxicity in various organs in vivo.......Widespread occupational exposure to carbon black nanoparticles (CBNPs) raises concerns over their safety. CBNPs are genotoxic in vitro but less is known about their genotoxicity in various organs in vivo....

  13. Climate Response due to Black Carbon Aerosols and Black-Carbon-induced SST Effects in MIROC5.0

    Science.gov (United States)

    Yu, Y.; Nakajima, T.; Goto, D.

    2014-12-01

    This study used the Models for Interdisciplinary Research on Climate, MIROC5.0, one member of the Coupled Model Intercomparison Project (CMIP5), to investigate the effects of black carbon (BC) aerosols on atmospheric circulations and climate including intricate feedback mechanism. The simulations with and without BC were conducted and the difference between these two runs is the corresponding response due to BC. Both atmosphere-ocean coupled general circulation model simulation (CGCM with full ocean) and the fixed SST runs (AGCM with prescribed sea surface temperature and sea ice temperature) were used to study the effects from ocean boundary conditions. The regional effects due to BC may be much larger than models have assumed (Andreae and Ramanathan, 2013; Bond et al., 2013). There are many studies used simplified mixed-layer ocean under prescribed surface heat flux to estimate the climate effect of BC (Kim et al., 2014), however these ocean-atmosphere coupled processes act on seasonal and annual time scales more real than non-ocean-atmosphere coupled models. Our results showed that the comprehensively sea-air interaction amplified the heating effect of black carbon aerosols; the presence of BC affected climate not only at local source areas but also at remote regions due to changes on energy transport processes and atmospheric circulations; we also discussed how the feedback of SST induced by BC affected on the distribution and magnitudes of climate response such as temperature, precipitation and cloud coverage between CGCM and AGCM runs.

  14. Contribution of regional transport to the black carbon aerosol during winter haze period in Beijing

    Science.gov (United States)

    Wang, Qiyuan; Huang, Ru-Jin; Cao, Junji; Tie, Xuexi; Shen, Zhenxing; Zhao, Shuyu; Han, Yongming; Li, Guohui; Li, Zhengqiang; Ni, Haiyan; Zhou, Yaqing; Wang, Meng; Chen, Yang; Su, Xiaoli

    2016-05-01

    The mass concentrations of atmospheric refractory black carbon (rBC), an important absorber of solar radiation, were continuously measured with a single particle soot photometer (SP2) during wintertime haze period to investigate the transport of pollution to Beijing. The average mass concentration of rBC was 6.1 ± 3.9 μg m-3 during hazy periods, which was 4.7 times higher than it during non-hazy periods. Cluster analysis showed that the air parcels arriving at Beijing mainly originated from the northwest, passed through the south and brought the most polluted air to Beijing. Concentration-weighted trajectory analyses indicated that the central North China Plain were the most likely source region for the rBC that impacted Beijing. Furthermore, the Weather Research and Forecasting-Black Carbon model showed that 71.4-82.0% of the rBC at Beijing was from regional transport during the high rBC episodes and that 47.9-56.8% of the rBC can be attributed to sources in the central North China Plain. These results suggest that regional transport from the central North China Plain, rather than local emissions, was a more important source for rBC pollution in Beijing.

  15. Preservation of black carbon in the shelf sediments of the East China Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Concentrations and carbon isotopic (14C, 13C) compositions of black carbon (BC) were measured for three sediment cores collected from the Changjiang River estuary and the shelf of the East China Sea. BC concentrations ranged from 0.02 to 0.14 mg/g (dry weight), and accounted for 5% to 26% of the sedimentary total organic carbon (TOC) pool. Among the three sediment cores collected at each site, sediment from the Changjiang River estuary had relatively high BC contents compared with the sediments from the East China Sea shelf, suggesting that the Changjiang River discharge played an important role in the delivery of BC to the coastal region. Radiocarbon measurements indicate that the ages of BC are in the range of 6910 to 12250 years old B.P. (before present), that is in general, 3700 to 9000 years older than the 14C ages of TOC in the sediments. These variable radiocarbon ages suggest that the BC preserved in the sediments was derived from the products of both biomass fire and fossil fuel combustion, as well as from ancient rock weathering. Based on an isotopic mass balance model, we calculated that fossil fuel combustion contributed most (60%―80%) of the BC preserved in these sediments and varied with depth and locations. The deposition and burial of this "slow-cycling" BC in the sediments of the East China Sea shelf represent a significant pool of carbon sink and could greatly in-fluence carbon cycling in the region.

  16. PM2.5 and aerosol black carbon in Suva, Fiji

    Science.gov (United States)

    Isley, C. F.; Nelson, P. F.; Taylor, M. P.; Mani, F. S.; Maata, M.; Atanacio, A.; Stelcer, E.; Cohen, D. D.

    2017-02-01

    Concentrations of particulate air pollution in Suva, Fiji, have been largely unknown and consequently, current strategies to reduce health risk from air pollution in Suva are not targeted effectively. This lack of air quality data is common across the Pacific Island Countries. A monitoring study, during 2014 and 2015, has characterised the fine particulate air quality in Suva, representing the most detailed study to date of fine aerosol air pollutants for the Pacific Islands; with sampling at City, Residential (Kinoya) and Background (Suva Point) sites. Meteorology for Suva, as it relates to pollutant dispersion for this period of time, has also been analysed. The study design enables the contribution of maritime air and the anthropogenic emissions to be carefully distinguished from each other and separately characterised. Back trajectory calculations show that a packet of air sampled at the Suva City site has typically travelled 724 km in the 24-h prior to sampling, mainly over open ocean waters; inferring that pollutants would also be rapidly transported away from Suva. For fine particulates, Suva City reported a mid-week PM2.5 of 8.6 ± 0.4 μg/m3, averaged over 13-months of gravimetric sampling. Continuous monitoring (Osiris laser photometer) suggests that some areas of Suva may experience levels exceeding the WHO PM2.5 guideline of 10 μg/m3, however, compared to other countries, Fiji's PM2.5 is low. Peak aerosol particulate levels, at all sites, were experienced at night-time, when atmospheric conditions were least favourable to dispersion of air pollutants. Suva's average ambient concentrations of black carbon in PM2.5, 2.2 ± 0.1 μg/m3, are, however, similar to those measured in much larger cities. With any given parcel of air spending only seven minutes, on average, over the land area of Suva Peninsula, these black carbon concentrations are indicative that significant combustion emissions occur within Suva. Many other communities in the Pacific Islands

  17. Brief Analysis on the Production & Operation Situation of Chinese Carbon Black Industry in the First Half Year

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    At present, there are about 120 carbon black manufacturing enterprises in China with the production capacity of 3.41 million tons, accounting for 78% of the total production capacity of the country, in which there are 31 carbon black enterprises with the production capacity of over 50,000 tons. Compared with the international carbon black industry, our carbon black industry has a low intensification.

  18. Analysis of the Thermal Conductivity of Polymer Nanocomposites Filled with Carbon Nanotubes and Carbon Black

    Directory of Open Access Journals (Sweden)

    R.V. Dinzhos

    2014-04-01

    Full Text Available Experimental results and theoretical studies of thermophysical characteristics crystalline polyethylene nanocomposites containing from 0.3 to 2.5 wt. % carbon black and nanocomposites containing from 0.2 to 1.5 wt. % carbon nanotubes is done in the article. The fundamentals of the effective medium theory and percolation theory and how they correlate with the experimental data is shown. The features of the structure’s influence of polymer composites on their thermal properties is studied. A comparative analysis of the thermal conductivity of the compositions according to the geometry of the filler is done.

  19. Atmospheric black carbon concentrations in North America, ~1100 to 2005. Liaquat Husain and Tanveer Ahmed Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA, and Department of Environmental Health Sciences, School of Public Health, State University of New York, Albany, NY, 12201-0509, USA

    Science.gov (United States)

    Husain, L.

    2013-05-01

    Black carbon (BC) aerosols in the atmosphere absorb solar radiation, and cause heating of the atmosphere, may alter Earth's cloud cover, and impact precipitation cycle. The best estimate for radiative forcing from BC with 90% certainty is + 1.1 Wm-2 ( + 0.17 to 2.1 Wm-2), second only to that of CO2. A major uncertainty in the estimation is a lack of atmospheric BC data. Models are used to estimate BC emissions into the atmosphere. They have not been validated by field data. We report measurements of BC in the atmosphere, over a period of several centuries using lake sediments. Retrieval of such records provides an invaluable source for understanding changes in the atmosphere with time. Numerous studies have been conducted with such an objective. Owing to a lack of knowledge of deposition rates of atmospheric aerosols into the lake sediments, a major shortcoming of these studies have been an inability to convert the measurements of chemical species in lake sediments into the atmosphere. We have developed a technique to overcome this shortcoming by measuring black carbon in atmospheric aerosols, and in lake sediment cores. The concentrations of BC were determined in daily filters collected at Whiteface Mountain, NY, from 1978 to 2005. Cores from two lakes around Whiteface Mountain, NY, were collected. Cores were (1) sectioned in thin slices, (2) freeze dried, (3) dated using the 210Pb technique, (4) BC chemically separated, and (5) concentrations measured using the thermal-optical method. By The deposition rate of BC from the atmosphere to the lakes was determined by comparing the BC concentration in air and the sediments for the 1978 -2005 period. The deposition rate so determined was used to concert the BC in the sediment into the atmosphere for the ~1978 to ~1100 period. The BC concentrations for the industrial period, ~1850 was low but rapidly increased from ~1900, peaked ~1925, decreased very slowly ~ 1980, followed by a sharp decrease. Concentrations has

  20. Electrical properties of foamed polypropylene/carbon black composites

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  3. Modeling the impact of black carbon on snowpack properties at an high altitude site in the Himalayas

    Science.gov (United States)

    Jacobi, Hans-Werner; Ménégoz, Martin; Gallée, Hubert; Lim, Saehee; Zanatta, Marco; Jaffrezo, Jean-Luc; Cozic, Julie; Laj, Paolo; Bonasoni, Paolo; Cristofanelli, Paolo; Stocchi, Paolo; Marinoni, Angela; Verza, Gianpietro; Vuillermoz, Elisa

    2013-04-01

    Light absorbing aerosols in the snow can modify the snow albedo. As a result, the seasonal snowpack can melt earlier compared to the unaffected snow leading to a warming effect on the atmosphere. Several global model studies have indicated that the long-range transport of light absorbing aerosols into the Himalayas and the subsequent deposition to the snow have contributed to a temperature rise in these regions. Due to its strong light absorbing properties, black carbon (BC) may play an important role in this process. To evaluate the possible impact of BC on snow albedo we determined BC concentrations in a range of fresh and older snow samples collected between 2009 and 2012 in the vicinity of the Pyramid station, Nepal at an altitude of more than 5000 m. BC concentrations in the snow were obtained after nebulizing the melted samples using a single particle soot photometer. The observed seasonal cycle in BC concentrations in the snow corresponds to observed seasonal cycles in atmospheric BC detected at the Pyramid station. Older snow showed somewhat higher concentrations compared to fresh snow samples indicating the influence of dry deposition of BC. In order to study in detail the impact of black carbon on snow properties, we upgraded the existing one-dimensional physical snowpack model CROCUS to account for the influence of black carbon on the absorption of radiation by the snow. A radiative transfer scheme was implemented into the snowpack model taking into account the solar zenith angle, the snow water equivalent and grain size, the soil albedo, and the concentration of black carbon in the snow. The upgraded model was applied to a high altitude site in the Himalayas using observed BC concentrations and meteorological data recorded at Pyramid station. First results of the simulations will be presented.

  4. Adsorption ability of the carbon black for nickel ions uptake from aqueous solution

    Directory of Open Access Journals (Sweden)

    Rađenović Ankica

    2013-01-01

    Full Text Available Surface modification can be performed by adsorption of certain organic compounds on the surface of carbon. The main objective of this work was to compare the adsorption ability of acid-modified carbon black with the non-modified one. Modification process was performed by adsorption of acetic acid onto commercial carbon black surface. A batch adsorption system was applied to study the both adsorption reaction, acetic acid and Ni(II adsorption onto the carbon black. Adsorption isotherms of acetic acid and Ni(II adsorption onto the non-modified and modified carbon black were fitted by classical adsorption models, such as Freundlich and Langmuir models. Modified carbon black surface become more active for Ni(II ions removal from aqueous solutions. The results showed that modification by acetic acid increases the adsorption capacity of carbon black from 18.3823 mg Ni(II g-1 to 86.9566 mg Ni(II g-1. SEM analysis enabled the observation of any surface changes in the carbon black that have occurred due to either acid modification or Ni(II adsorption.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Factors controlling black carbon distribution in the Arctic

    Science.gov (United States)

    Qi, Ling; Li, Qinbin; Li, Yinrui; He, Cenlin

    2017-01-01

    We investigate the sensitivity of black carbon (BC) in the Arctic, including BC concentration in snow (BCsnow, ng g-1) and surface air (BCair, ng m-3), as well as emissions, dry deposition, and wet scavenging using the global three-dimensional (3-D) chemical transport model (CTM) GEOS-Chem. We find that the model underestimates BCsnow in the Arctic by 40 % on average (median = 11.8 ng g-1). Natural gas flaring substantially increases total BC emissions in the Arctic (by ˜ 70 %). The flaring emissions lead to up to 49 % increases (0.1-8.5 ng g-1) in Arctic BCsnow, dramatically improving model comparison with observations (50 % reduction in discrepancy) near flaring source regions (the western side of the extreme north of Russia). Ample observations suggest that BC dry deposition velocities over snow and ice in current CTMs (0.03 cm s-1 in the GEOS-Chem) are too small. We apply the resistance-in-series method to compute a dry deposition velocity (vd) that varies with local meteorological and surface conditions. The resulting velocity is significantly larger and varies by a factor of 8 in the Arctic (0.03-0.24 cm s-1), which increases the fraction of dry to total BC deposition (16 to 25 %) yet leaves the total BC deposition and BCsnow in the Arctic unchanged. This is largely explained by the offsetting higher dry and lower wet deposition fluxes. Additionally, we account for the effect of the Wegener-Bergeron-Findeisen (WBF) process in mixed-phase clouds, which releases BC particles from condensed phases (water drops and ice crystals) back to the interstitial air and thereby substantially reduces the scavenging efficiency of clouds for BC (by 43-76 % in the Arctic). The resulting BCsnow is up to 80 % higher, BC loading is considerably larger (from 0.25 to 0.43 mg m-2), and BC lifetime is markedly prolonged (from 9 to 16 days) in the Arctic. Overall, flaring emissions increase BCair in the Arctic (by ˜ 20 ng m-3), the updated vd more than halves BCair (by ˜ 20 ng m-3

  7. Interaction between carboxyl-functionalized carbon black nanoparticles and porous media

    Science.gov (United States)

    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

  8. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly...... to either carbon dioxide pneumoperitoneum or abdominal wall lifting for laparoscopic colectomy. Despite an increasing metabolic acidosis, prolonged carbon dioxide pneumoperitoneum resulted in only a slight increase in plasma potassium concentrations, which was both statistically and clinically insignificant....... Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery....

  9. Serum creatinine concentration at the onset of uremia: higher levels in black males.

    Science.gov (United States)

    Abuelo, J G; Shemin, D; Chazan, J A

    1992-06-01

    We compared serum creatinine and blood urea nitrogen concentrations, estimated creatinine clearances and frequency of uremic symptoms at the start of chronic hemodialysis in all 20 black and 179 white males treated between 1969 and 1983. Serum creatinine concentrations were significantly higher in black males (16.5 +/- 5.9 mg/dl) than in white males (11.7 +/- 4.7 mg/dl; p = 0.016). There were no significant differences in blood urea nitrogen concentration, estimated creatinine clearance and frequency of uremic symptoms between the two groups. Blood urea nitrogen to serum creatinine ratios were lower in black males, (7.3 +/- 1.9) than in white males (11.4 +/- 3.8; p = 0.0001), and only one black male had a ratio greater than 10 compared to 60% of whites. We concluded that black males tend to have higher serum creatinine concentrations than white males at the onset of uremic symptoms, and that higher striated muscle creatinine production in black males and not lower renal function may be the cause.

  10. Modified thermal-optical analysis using spectral absorption selectivity to distinguish black carbon from pyrolized organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, Odelle; Hadley, O.L.; Corrigan, C.E.; Kirchstetter, T.W.

    2008-04-14

    Black carbon (BC), a main component of combustion-generated soot, is a strong absorber of sunlight and contributes to climate change. Measurement methods for BC are uncertain, however. This study presents a method for analyzing the BC mass loading on a quartz fiber filter using a modified thermal-optical analysis method, wherein light transmitted through the sample is measured over a spectral region instead of at a single wavelength as the sample is heated. Evolution of the spectral light transmission signal depends on the relative amounts of light-absorbing BC and char, the latter of which forms when organic carbon in the sample pyrolyzes during heating. Absorption selectivities of BC and char are found to be distinct and are used to apportion the amount of light attenuated by each component in the sample. Light attenuation is converted to mass concentration based on derived mass attenuation efficiencies (MAE) of BC and char. The fraction of attenuation due to each component are scaled by their individual MAE values and added together as the total mass of light absorbing carbon (LAC). An iterative algorithm is used to find the MAE values for both BC and char that provide the best fit to the carbon mass remaining on the filter (derived from direct measurements of thermally evolved CO{sub 2}) at temperatures higher than 480 C. This method was applied to measure the BC concentration in precipitation samples collected from coastal and mountain sites in Northern California. The uncertainty in measured BC concentration of samples that contained a high concentration of organics susceptible to char ranged from 12 to 100 percent, depending on the mass loading of BC on the filter. The lower detection limit for this method was approximately 0.35 {micro}g BC and uncertainty approached 20 percent for BC mass loading greater than 1.0 {micro}g BC.

  11. Distribution and preservation of black carbon in the East China Sea sediments: Perspectives on carbon cycling at continental margins

    Science.gov (United States)

    Huang, Liang; Zhang, Jing; Wu, Ying; Wang, Jinlong

    2016-02-01

    We determined the concentrations and radiocarbon (14C) compositions of black carbon (BC) in the sediments of the East China Sea (ECS). The BC concentrations, which were in the range of 0.30-1.52 mg/g, accounted for 12-65% of the total organic carbon (TOC). The distribution of BC in ECS sediments was controlled by factors such as grain size, distance from the coast, and deposition rate. Radiocarbon measurements of BC yielded ages of 6350-10,440 years before present (BP), suggesting that the percentage of BC derived from biomass combustion was in the range of 29-48%. The BC burial flux in sediments of the ECS was estimated to be ∼1.39×106 t/yr, which was similar to burial fluxes reported for shelf sediments in other areas. However, the magnitude of the total BC sink was far greater than that of any other shelf regions studied to date, indicating the global importance of BC accumulation in the ECS, and the magnitude of BC input from large rivers (e.g., the Changjiang). The riverine delivery of BC to the ECS (73%) was far greater than that of atmospheric flux (27%). Further study of the BC cycle and the interactions of BC with other organic compounds in marginal seas was required to better understand the role of BC in the global carbon cycle.

  12. Comparing black carbon types in sequestering polybrominated diphenyl ethers (PBDEs) in sediments.

    Science.gov (United States)

    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.

  13. Classroom Carbon Dioxide Concentration, School Attendance, and Educational Attainment

    Science.gov (United States)

    Gaihre, Santosh; Semple, Sean; Miller, Janice; Fielding, Shona; Turner, Steve

    2014-01-01

    Background: We tested the hypothesis that classroom carbon dioxide (CO[subscript 2]) concentration is inversely related to child school attendance and educational attainment. Methods: Concentrations of CO[subscript 2] were measured over a 3-5?day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of…

  14. Dielectric study of Poly(styrene- co -butadiene) Composites with Carbon Black, Silica, and Nanoclay

    KAUST Repository

    Vo, Loan T.

    2011-08-09

    Dielectric spectroscopy is used to measure polymer relaxation in styrene-butadiene rubber (SBR) composites. In addition to the bulk polymer relaxation, the SBR nanocomposites also exhibit a slower relaxation attributed to polymer relaxation at the polymer-nanoparticle interface. The glass transition temperature associated with the slower relaxation is used as a way to quantify the interaction strength between the polymer and the surface. Comparisons were made among composites containing nanoclay, silica, and carbon black. The interfacial relaxation glass transition temperature of SBR-clay nanocomposites is more than 80 °C higher than the SBR bulk glass transition temperature. An interfacial mode was also observed for SBR-silica nanocomposites, but the interfacial glass transition temperature of SBR-silica nanocomposite is somewhat lower than that of clay nanocomposites. An interfacial mode is also seen in the carbon black filled system, but the signal is too weak to analyze quantitatively. The interfacial polymer relaxation in SBR-clay nanocomposites is stronger compared to both SBR-carbon black and SBR-silica composites indicating a stronger interfacial interaction in the nanocomposites containing clay. These results are consistent with dynamic shear rheology and dynamic mechanical analysis measurements showing a more pronounced reinforcement for the clay nanocomposites. Comparisons were also made among clay nanocomposites using different SBRs of varying styrene concentration and architecture. The interfacial glass transition temperature of SBR-clay nanocomposites increases as the amount of styrene in SBR increases indicating that styrene interacts more strongly than butadiene with clay. © 2011 American Chemical Society.

  15. Black carbon emissions from in-use ships: a California regional assessment

    Directory of Open Access Journals (Sweden)

    G. M. Buffaloe

    2013-09-01

    Full Text Available Black carbon (BC mass emission factors (EFBC; g-BC (kg-fuel−1 from a variety of ocean going vessels have been determined from measurements of BC and carbon dioxide (CO2 concentrations in ship plumes intercepted by the R/V Atlantis during the 2010 California Nexus (CalNex campaign. The ships encountered were all operating within 24 nautical miles of the California coast and were utilizing relatively low sulphur fuels. Black carbon concentrations within the plumes, from which EFBC values are determined, were measured using four independent instruments: a photoacoustic spectrometer and a particle soot absorption photometer, which measure light absorption, and a single particle soot photometer and soot particle aerosol mass spectrometer, which measure the mass concentration of refractory BC directly. The measured EFBC have been divided into vessel type categories and engine type categories, from which averages have been determined. The geometric average EFBC, determined from over 71 vessels and 135 plumes encountered, was 0.31 g-BC (kg-fuel−1. The most frequent engine type encountered was the slow speed diesel (SSD, and the most frequent SSD vessel type was the cargo ship sub-category. Average and median EFBC values from the SSD category are compared with previous observations from the Texas Air Quality Study (TexAQS in 2006, during which the ships encountered were predominately operating on high sulphur fuels. There is a statistically significant difference between the EFBC values from CalNex and TexAQS for SSD vessels and for the cargo and tanker ship types within this engine category. The CalNex EFBC values are lower than those from TexAQS, suggesting that operation on lower sulphur fuels is associated with smaller EFBC values.

  16. Feasibility study of production of radioactive carbon black or carbon nanotubes in cyclotron facilities for nanobioscience applications.

    Science.gov (United States)

    Abbas, K; Simonelli, F; Holzwarth, U; Cydzik, I; Bulgheroni, A; Gibson, N; Kozempel, J

    2013-03-01

    A feasibility study regarding the production of radioactive carbon black and nanotubes has been performed by proton beam irradiation. Experimental and theoretical excitation functions of the nuclear reaction (nat)C(p,x)(7)Be in the proton energy range 24-38 MeV are reported, with an acceptable agreement. We have demonstrated that sufficient activities of (7)Be radioisotope can be produced in carbon black and nanotube that would facilitate studies of their possible impact on human and environment.

  17. Concentration Levels of Imidacloprid and Dinotefuran in Five Tissue Types of Black Walnut, Juglans nigra

    OpenAIRE

    Paul Merten; Jerome Grant; Carla Coots; Katheryne Nix; Paris Lambdin

    2013-01-01

    Black walnut, a valuable economic and environmentally important species, is threatened by thousand cankers disease. Systemic imidacloprid and dinotefuran applications were made to mature black walnut trees to evaluate their translocation and concentration levels in various tissue types including leaf, twig, trunk core, nutmeat, and walnut husk. The metabolism of imidacloprid in plants produces a metabolite, olefin-imidacloprid, which has been documented to have insecticidal properties in othe...

  18. Organic carbon isotopes of the Sinian and Early Cambrian black shales on Yangtze Platform, China

    Institute of Scientific and Technical Information of China (English)

    李任伟; 卢家烂; 张淑坤; 雷加锦

    1999-01-01

    Organic matter of the Sinian and early Cambrian black shales on the Yangtze Platform belongs to the light carbon group of isotopes with the δ13C values from - 27 % to -35 % , which are lower than those of the contemporaneously deposited carbonates and phosphorites. A carbon isotope-stratified paleooceanographic model caused by upwelling is proposed, which can be used not only to interpret the characteristics of organic carbon isotopic compositions of the black shales, but also to interpret the paleogeographic difference in the organic carbon isotope compositions of various types of sedimentary rocks.

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

    Science.gov (United States)

    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.

  20. The impact of black wattle encroachment of indigenous grasslands on soil carbon, Eastern Cape, South Africa

    DEFF Research Database (Denmark)

    Oelofse, Myles; Birch-Thomsen, Torben; Magid, Jakob;

    2016-01-01

    adverse environmental impacts in South Africa. Little is known about the effects of black wattle encroachment on soil carbon, therefore the aim of this study was to investigate the impact of black wattle encroachment of natural grassland on soil carbon stocks and dynamics. Focussing on two sites...... in the Eastern Cape, South Africa, the study analysed carbon stocks in soil and litter on a chronosequence of black wattle stands of varying ages (up to >50 years) and compared these with adjacent native grassland. The study found that woody encroachment of grassland at one site had an insignificant effect...

  1. Grafted, cross-linked carbon black as a double-layer capacitor electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Wokaun, A.

    2001-03-01

    Isocyanate prepolymers readily react with oxidic functional groups on carbon black. On carbon black grafted with diisocyanates, reactive isocyanate groups are available for cross-linking to a polyurethane system. This cross-linked carbon black was considered as a new active material for electrochemical electrodes. Active material for electric double-layer capacitor electrodes was produced which had values of specific capacitance of up to 200 F/g. Cross-linking efficiencies of up to 58 % of the polymers utilised were achieved. (author)

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

    Science.gov (United States)

    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

  3. The sources of atmospheric black carbon at a European gateway to the Arctic

    Science.gov (United States)

    Winiger, P.; Andersson, A.; Eckhardt, S.; Stohl, A.; Gustafsson, Ö.

    2016-09-01

    Black carbon (BC) aerosols from incomplete combustion of biomass and fossil fuel contribute to Arctic climate warming. Models--seeking to advise mitigation policy--are challenged in reproducing observations of seasonally varying BC concentrations in the Arctic air. Here we compare year-round observations of BC and its δ13C/Δ14C-diagnosed sources in Arctic Scandinavia, with tailored simulations from an atmospheric transport model. The model predictions for this European gateway to the Arctic are greatly improved when the emission inventory of anthropogenic sources is amended by satellite-derived estimates of BC emissions from fires. Both BC concentrations (R2=0.89, PArctic, and a more credible scientific underpinning of policy efforts aimed at efficiently reducing BC emissions reaching the European Arctic.

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

    Science.gov (United States)

    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.

  5. Changes in plasma potassium concentration during carbon dioxide pneumoperitoneum

    DEFF Research Database (Denmark)

    Perner, A; Bugge, K; Lyng, K M

    1999-01-01

    Hyperkalaemia with ECG changes had been noted during prolonged carbon dioxide pneumoperitoneum in pigs. We have compared plasma potassium concentrations during surgery in 11 patients allocated randomly to undergo either laparoscopic or open appendectomy and in another 17 patients allocated randomly....... Thus hyperkalaemia is unlikely to develop in patients with normal renal function undergoing carbon dioxide pneumoperitoneum for laparoscopic surgery....

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

    Science.gov (United States)

    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. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity

    Energy Technology Data Exchange (ETDEWEB)

    Montelongo-Reyes, M.M.; Otazo-Sánchez, E.M.; Romo-Gómez, C.; Gordillo-Martínez, A.J.; Galindo-Castillo, E.

    2015-09-15

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO{sub 2} emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO{sub 2} sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO{sub 2} gas emissions were also significant, particularly SO{sub 2} (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries. - Highlights: • First GHG & black carbon inventory for Mezquital Valley: Mexico City energy supplier • Energy industries caused the largest CO{sub 2} and SO{sub 2} emissions from residual fuel oil. • Diesel

  8. 高结构炭黑酸化改性的研究%Research on High Structure Carbon Black Modification of Acidification

    Institute of Scientific and Technical Information of China (English)

    孟春财; 陈建; 金永中; 张敬雨; 伍雅峰

    2012-01-01

    The experimental samples were made by changing the reaction time and acid concentration and acidizing to modify different high structure carbon black. The dispersion and stability of the modified carbon black in aqueous solution was determined by natural sedimentation method. The shading rate of each modified carbon black was detected by the laser particle size analyzer. The relationship between the surface groups of carbon black and its dispersion was analysed quantitatively by acid-base titratioa And the performance indicators were compared between the modified carbon black and carbon black pigment. The results showed that, the modified carbon black, which was prepared by the N234 carbon black and 6mol/L sulfuric acid for 8 hours, dispersed best, due to the content increase of phenolic hydroxyl and lactone. Comparing the dispersion of carbon black and the price, the modified carbon black was better than the pigment carbon black.%通过改变时间、硫酸浓度等反应条件,酸化改性不同品种炭黑,得到了实验所需试样.采用自然沉降法测定了酸化改性高结构炭黑在水溶液中的分散性及稳定性.利用激光粒度分布仪检测了每种改性炭黑的遮光率,根据酸碱滴定法定量分析了炭黑表面基团与分散性的关系,并比较了改性炭黑与色素炭黑之间的性能指标.结果表明,炭黑N234与6mol/L硫酸反应8h制备的改性炭黑分散性最佳,原因是其表面的酚羟基和内酯基含量有所增加.通过比较炭黑的分散性及市场价格,得知改性炭黑优于色素炭黑.

  9. Mobility of rhenium, platinum group elements and organic carbon during black shale weathering

    Science.gov (United States)

    Jaffe, Lillie A.; Peucker-Ehrenbrink, Bernhard; Petsch, Steven T.

    2002-05-01

    This study investigates the effects of black shale weathering on the Re-Os isotope system, platinum group element concentrations and the degradation of organic matter. Samples from a weathering profile in Late Devonian (˜365 Myr) Ohio Shale show a pronounced decrease (˜77%) in organic carbon (C org) near the present soil surface, relative to the interior portion of the outcrop. A similar trend is observed for total N (˜67% loss). Conversely, organic phosphorus (P org) concentrations increase by ˜59% near the soil surface. The decrease in C org is accompanied by a pronounced decrease in Re (˜99%) and, to a lesser extent, Os (˜39%). Palladium and Pt do not appear to be significantly mobile. The effects of Re and Os mobility on the Re-Os isotope system are significant: none of the samples plots on a 365 Myr isochron. Rather, the samples define a trend with a slope corresponding to an age of ˜18 Myr with an initial 187Os/ 188Os of ˜6.1. This indicates recent disturbance of the Re-Os system. Isotope mass balance calculations imply that the labile fraction of Os is significantly more radiogenic ( 187Os/ 188Os of ˜7.8) than the average of the unweathered samples ( 187Os/ 188Os of ˜6.4). Based on data from this study, the molar ratio of labile Re to C org in Ohio Shale is estimated at 7×10 -8. We estimate the present-day riverine, black shale-derived Re flux to seawater using literature data on Re burial in anoxic marine sediments, and assuming steady-state between Re release during black shale weathering and Re burial in anoxic marine sediments. Then, the labile Re/C org observed in this study implies that ˜0.5 Tmol of C org is released annually from weathering of black shales, a trace lithology in the continental crust. This flux corresponds to ˜12% of the estimated annual CO 2 flux from oxidative weathering of sedimentary rocks. The labile molar Re/Os of ˜270 indicates that black shale weathering releases ˜130 mol Os per year, which accounts for ˜7% of

  10. Atmospheric Black Carbon along a Cruise Path through the Arctic Ocean during the Fifth Chinese Arctic Research Expedition

    OpenAIRE

    2014-01-01

    From July to September 2012, during the fifth Chinese National Arctic Research Expedition (CHINARE), the concentrations of black carbon (BC) aerosols inside the marine boundary layer were measured by an in situ aethalometer. BC concentrations ranged from 0.20 ng∙m−3 to 1063.20 ng∙m−3, with an average of 75.74 ng∙m−3. The BC concentrations were significantly higher over the mid-latitude and coastal areas than those over the remote ocean and high latitude areas. The highest average concentratio...

  11. Sulfonated carbon black-based composite membranes for fuel cell applications

    Indian Academy of Sciences (India)

    Hacer Doǧan; Emel Yildiz; Metin Kaya; Tülay Y Inan

    2013-08-01

    Two different commercial grade carbon black samples, Cabot Regal 400R (C1) and Cabot Mogul L (C2), were sulfonated with diazonium salt of sulfanilic acid. The resultant sulfonated carbon black samples (S–C) were characterized by Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA). Composite membranes were then prepared using S–C as fillers and sulfonated poly(ether ether ketone) (SPEEK) as polymer matrix with three different sulfonation degrees (DS = 60, 70 and 82%). Structure and properties of the composite membranes were characterized by FTIR, TGA, scanning electron microscopy, proton conduction, water uptake, ion exchange capacity and chemical stability. Incorporation of S–C particles above 0.25 wt% caused decrease in chemical stability. Pristine and composite membranes prepared from SPEEK82 decomposed completely in <1 h, which is undesirable for fuel cell applications. SPEEK60 membrane having wt% of 0.25–0.5 with S–C particles led to higher proton conductivity than that of pristine membrane. No positive effect was observed on the properties of the composite membranes with the addition of S–C particles at high concentrations due to the agglomeration problems and decrease in the content of conductive polymer matrix.

  12. Distribution and Sources of Black Carbon in the Arctic

    Science.gov (United States)

    Qi, Ling

    The Arctic is warming at twice the global rate over recent decades. To slow down this warming trend, there is growing interest in reducing the impact from short-lived climate forcers, such as black carbon (BC), because the benefits of mitigation are seen more quickly relative to CO2 reduction. To propose efficient mitigation policies, it is imperative to improve our understanding of BC distribution in the Arctic and to identify the sources. In this dissertation, we investigate the sensitivity of BC in the Arctic, including BC concentrations in snow (BCsnow) and BC concentrations in air (BCair), to emissions, dry deposition and wet scavenging using a global 3-D chemical transport model (CTM) GEOS-Chem. By including flaring emissions, estimating dry deposition velocity using resistance-in-series method, and including Wegener-Bergeron-Findeisen (WBF) in wet scavenging, simulated BCsnow in the eight Arctic sub-regions agree with the observations within a factor of two, and simulated BCair fall within the uncertainty range of observations. Specifically, we find that natural gas flaring emissions in Western Extreme North of Russia (WENR) strongly enhance BCsnow (by up to ?50%) and BCair (by 20-32%) during snow season in the so-called 'Arctic front', but has negligible impact on BC in the free troposphere. The updated dry deposition velocity over snow and ice is much larger than those used in most of global CTMs and agrees better with observation. The resulting BCsnow changes marginally because of the offsetting of higher dry and lower wet deposition fluxes. In contrast, surface BCair decreases strongly due to the faster dry deposition (by 27-68%). WBF occurs when the environmental vapor pressure is in between the saturation vapor pressure of ice crystals and water drops in mixed-phase clouds. As a result, water drops evaporate and releases BC particles in them back into the interstitial air. In most CTMs, WBF is either missing or represented by a uniform and low BC

  13. Russia's black carbon emissions: focus on diesel sources

    Science.gov (United States)

    Kholod, Nazar; Evans, Meredydd; Kuklinski, Teresa

    2016-09-01

    Black carbon (BC) is a significant climate forcer with a particularly pronounced forcing effect in polar regions such as the Russian Arctic. Diesel combustion is a major global source of BC emissions, accounting for 25-30 % of all BC emissions. While the demand for diesel is growing in Russia, the country's diesel emissions are poorly understood. This paper presents a detailed inventory of Russian BC emissions from diesel sources. Drawing on a complete Russian vehicle registry with detailed information about vehicle types and emission standards, this paper analyzes BC emissions from diesel on-road vehicles. We use the COPERT emission model (COmputer Programme to calculate Emissions from Road Transport) with Russia-specific emission factors for all types of on-road vehicles. On-road diesel vehicles emitted 21 Gg of BC in 2014: heavy-duty trucks account for 60 % of the on-road BC emissions, while cars represent only 5 % (light commercial vehicles and buses account for the remainder). Using Russian activity data and fuel-based emission factors, the paper also presents BC emissions from diesel locomotives and ships, off-road engines in industry, construction and agriculture, and generators. The study also factors in the role of superemitters in BC emissions from diesel on-road vehicles and off-road sources. The total emissions from diesel sources in Russia are estimated to be 49 Gg of BC and 17 Gg of organic carbon (OC) in 2014. Off-road diesel sources emitted 58 % of all diesel BC in Russia.

  14. Wetting and Non-Wetting Models of Black Carbon Activation

    Science.gov (United States)

    Henson, B. F.; Laura, S.

    2006-12-01

    We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (wetting). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-wetting). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a

  15. Micromorphological evidence of black carbon in colluvial soils from NW Spain

    NARCIS (Netherlands)

    Kaal, J.; van Mourik, J.M.

    2008-01-01

    Biomass burning produces a residue called black carbon (BC). Black C is generally considered to be highly resistant against biodegradation and has a potential role in the global C cycle, but is difficult to identify and quantify when subjected to prolonged degradation in terrestrial sediments. The c

  16. Simplifying the calculation of light scattering properties for black carbon fractal aggregates

    Directory of Open Access Journals (Sweden)

    A. J. A. Smith

    2014-08-01

    Full Text Available Black carbon fractal aggregates have complicated shapes that make the calculation of their optical properties particularly computationally expensive. Here, a method is presented to estimate fractal aggregate light scattering properties by optimising simplified models to full light scattering calculations. It is found that there are no possible spherical models (at any size or refractive index that well represent the light scattering in the visible or near-thermal infrared. As such, parameterisations of the light scattering as a function of the number of aggregate particles is presented as the most pragmatic choice for modelling distributions of black carbon when the large computational overheads of rigorous scattering calculations cannot be justified. This parameterisation can be analytically integrated to provide light scattering properties for lognormal distributions of black carbon fractal aggregates and return extinction cross sections with 0.1% accuracy for typical black carbon size distributions. Scattering cross sections and the asymmetry parameter can be obtained to within 3%.

  17. Simplifying the calculation of light scattering properties for black carbon fractal aggregates

    Science.gov (United States)

    Smith, A. J. A.; Grainger, R. G.

    2014-02-01

    Black carbon fractal aggregates have complicated shapes that make the calculation of their optical properties particularly computationally expensive. Here, a method is presented to estimate fractal aggregate light scattering properties by optimising simplified models to full light scattering calculations. It is found that there are no possible spherical models (at any size or refractive index) that well represent the light scattering in the visible, or near-thermal infrared. As such, parameterisations of the light scattering as a function of the number of aggregate particles is presented as the most pragmatic choice for modelling distributions of black carbon when the large computational overheads of rigorous scattering calculations cannot be justified. This parameterisation can be analytically integrated to provide light scattering properties for log-normal distributions of black carbon fractal aggregates and return extinction cross-sections with 0.1% accuracy for typical black carbon size distributions. Scattering cross-sections and the asymmetry parameter can be obtained to within 3%.

  18. Improved piezoelectricity of PVDF-HFP/carbon black composite films

    Science.gov (United States)

    Wu, Liangke; Yuan, Weifeng; Hu, Ning; Wang, Zhongchang; Chen, Chunlin; Qiu, Jianhui; Ying, Ji; Li, Yuan

    2014-04-01

    We report a substantial improvement of piezoelectricity for poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) copolymer films by introducing carbon black (CB) into the PVDF-HFP to form PVDF-HFP/CB composite films. The optimized output voltage of the composite film at an optimal CB content of 0.5 wt% is found to be 204% of the pristine PVDF-HFP film. Its harvested electrical power density is 464% and 561% of the pristine PVDF-HFP film by using ac and dc circuits, respectively. Through Fourier transform infrared spectroscopy analysis, differential scanning calorimetry analysis, and polarized optical microscopy observations, we clarify the enhancement mechanism of piezoelectricity for the PVDF-HFP/CB composite films. We find that the added CB acts as nucleating agent during the initial formation of crystals, but imposes an insignificant effect on the α-β phase transformation during stretching. We also demonstrate that the addition of optimal CB reduces crystal size yet increases the number of crystals in the composite films. This is beneficial for the formation of elongated, oriented and fibrillar crystalline morphology during stretching and consequently results in a highly efficient poling process. The addition of overdosed CB leads to the formation of undersized crystals, lowered crystallinity, and hence reduced piezoelectric performance of the PVDF-HFP/CB composite films.

  19. Characterization of PZT/PVC Composites Added with Carbon Black

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaofang; XIONG Chuanxi; SUN Huajun; DONG Lijie; LI Rui; LIU Yang

    2005-01-01

    A new three-phase PZT/ C/ PVC composite comprising PZT (50vol%), nanocrystalline PVC (50 vol% ) and a small volume fraction f of carbon black (C) was prepared by the hot-pressing technique. The dielectric property of the composite as a function of the frequency and the dielectric and piezoelectric properties as a function of the volume fraction f of C were studied. The measured dielectric property demonstrates that a percolation transition occurs in the three-phase composites as in normal two-phase metal-insulator continuum media. The dielectric constant varies slightly with f at f < 0.1 and increases rapidly when f is close to the percolation threshold at 1 kHz. The optimum properties were obtained for f = 0.5 before the percolation threshold in the PZT/ C/ PVC (50/f/(50 - f) vol% ) composite with its d33 (20 pC/N) being 50% higher than that of the PZT/ PVC (50/50vol% ), and its g33(47.23 × 10-3 Vm/N) and Kp (0.25) much higher than the earlier reported values.XRD patterns and P-E hysteresis loops were used to interpret the experimental results.

  20. Black carbon absorption effects on cloud cover, review and synthesis

    Directory of Open Access Journals (Sweden)

    D. Koch

    2010-03-01

    Full Text Available Absorbing aerosols (AA's such as black carbon (BC or dust absorb incoming solar radiation, perturb the temperature structure of the atmosphere, and influence cloud cover. Previous studies have described conditions where AA's either increase or decrease cloud cover. The effect depends on several factors, including the altitude of the AA relative to the cloud and on the cloud type. Cloud cover is decreased if the AA's are embedded in the cloud layer. AA's below cloud may enhance convection and cloud cover. AA's over cloud-level stabilize the underlying layer and tend to enhance stratocumulus clouds but may reduce cumulus clouds. AA's can also promote cloud cover in convergent regions as they enhance deep convection and low level convergence as it draws in moisture from ocean to land regions. Most global model studies indicate a regional variation in the cloud response but generally increased cloud cover over oceans and some land regions, with net increased low-level and/or reduced upper level cloud cover. The result is net negative radiative forcing from cloud response to AA's. In some of these climate model studies, the cooling effect of BC due to cloud changes was strong enough to essentially cancel the warming direct effects.

  1. Field Measurements of Black Carbon Yields from Gas Flaring.

    Science.gov (United States)

    Conrad, Bradley M; Johnson, Matthew R

    2017-02-07

    Black carbon (BC) emissions from gas flaring in the oil and gas industry are postulated to have critical impacts on climate and public health, but actual emission rates remain poorly characterized. This paper presents in situ field measurements of BC emission rates and flare gas volume-specific BC yields for a diverse range of flares. Measurements were performed during a series of field campaigns in Mexico and Ecuador using the sky-LOSA optical measurement technique, in concert with comprehensive Monte Carlo-based uncertainty analyses. Parallel on-site measurements of flare gas flow rate and composition were successfully performed at a subset of locations enabling direct measurements of fuel-specific BC yields from flares under field conditions. Quantified BC emission rates from individual flares spanned more than 4 orders of magnitude (up to 53.7 g/s). In addition, emissions during one notable ∼24-h flaring event (during which the plume transmissivity dropped to zero) would have been even larger than this maximum rate, which was measured as this event was ending. This highlights the likely importance of superemitters to global emission inventories. Flare gas volume-specific BC yields were shown to be strongly correlated with flare gas heating value. A newly derived correlation fitting current field data and previous lab data suggests that, in the context of recent studies investigating transport of flare-generated BC in the Arctic and globally, impacts of flaring in the energy industry may in fact be underestimated.

  2. Characteristics and source of black carbon aerosol over Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    FU; S.Joshua

    2010-01-01

    Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter>spring>autumn>summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,which was just the reverse of that in the urban area.The contribution of BC to the total mass of PM10 on non-dust storm days was~11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,and the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.

  3. Black carbon aerosols and the third polar ice cap

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Black carbon aerosols and the third polar ice cap

    Directory of Open Access Journals (Sweden)

    S. Menon

    2009-12-01

    Full Text Available 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 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 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 ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~30%, 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.

  5. Black carbon aerosols and the third polar ice cap

    Directory of Open Access Journals (Sweden)

    S. Menon

    2010-05-01

    Full Text Available 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 ~0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is ~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.

  6. Sources of uncertainties in modelling black carbon at the global scale

    OpenAIRE

    2010-01-01

    Our understanding of the global black carbon (BC) cycle is essentially qualitative due to uncertainties in our knowledge of its properties. This work investigates two source of uncertainties in modelling black carbon: those due to the use of different schemes for BC ageing and its removal rate in the global Transport-Chemistry model TM5 and those due to the uncertainties in the definition and quantification of the observations, which propagate through to both the emission inventories, and the...

  7. The Influence of Unidirectional Pressure on Electrical Conductivity of Carbon Black Filled Polyethylene

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; ZHANG Guo; ZHAO Zhudi; PENG Yi; DI Weihua; DU Chuang

    2006-01-01

    High density polyethylene filled with conductive carbon black was prepared by conventional melt-mixing method. The effect of unidirectional pressure on the conductivity was studied. Wide angle X-ray diffraction (WAXD) was used to show the influence of pressure on the aggregate structure of the polymer filled with carbon black (CB) fillers. A model on the basis of the formation and destruction of conductive networks was proposed to explain the change in the conductivity with the application of pressure.

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

    Science.gov (United States)

    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 (...

  9. Catalytic Oxidation of Propylene, Toluene, Carbon Monoxide, and Carbon Black over Au/CeO2 Solids: Comparing the Impregnation and the Deposition-Precipitation Methods

    Directory of Open Access Journals (Sweden)

    Antoine Aboukaïs

    2013-01-01

    Full Text Available Au/CeO2 solids were prepared by two methods: deposition-precipitation (DP and impregnation (Imp. The prepared solids were calcined under air at 400°C. Both types of catalysts have been tested in the total oxidation of propylene, toluene, carbon monoxide, and carbon black. Au/CeO2-DP solids were the most reactive owing to the high number of gold nanoparticles and Au+ species and the low concentration of Cl- ions present on its surface compared to those observed in Au/CeO2-Imp solids.

  10. Seasonality of Black Carbon over the Great Lakes

    Science.gov (United States)

    Spak, S. N.; Holloway, T.

    2006-12-01

    We employ a 2001 annual simulation with the Community Multiscale Air Quality Model to identify patterns in the mass concentration and aerosol fraction of elemental carbon in the Upper Midwestern United States. CMAQ 4.3 is run at 36 km resolution using the 2001 EPA Clean Air Interstate Rule emissions inventory, MM5 meteorology, and boundary conditions from the MOZART global atmospheric chemistry model. Results are compared to daily-average surface observations from the IMPROVE and EPA Speciation Trends networks. Effects of CMAQ model configuration (plume-in-grid dispersion, advection scheme, sectional PM) are compared, identifying common findings and model-dependent features.

  11. Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers

    Directory of Open Access Journals (Sweden)

    Aron eStubbins

    2015-10-01

    Full Text Available Wildfires have produced black carbon (BC since land plants emerged. Condensed aromatic compounds, a form of BC, have accumulated to become a major component of the soil carbon pool. Condensed aromatics leach from soils into rivers, where they are termed dissolved black carbon (DBC. The transport of DBC by rivers to the sea is a major term in the global carbon and BC cycles. To estimate Arctic river DBC export, 25 samples collected from the six largest Arctic rivers (Kolyma, Lena, Mackenzie, Ob’, Yenisey and Yukon were analyzed for dissolved organic carbon (DOC, colored dissolved organic matter (CDOM, and DBC. A simple, linear regression between DOC and DBC indicated that DBC accounted for 8.9 ± 0.3% DOC exported by Arctic rivers. To improve upon this estimate, an optical proxy for DBC was developed based upon the linear correlation between DBC concentrations and CDOM light absorption coefficients at 254 nm (a254. Relatively easy to measure a254 values were determined for 410 Arctic river samples between 2004 and 2010. Each of these a254 values was converted to a DBC concentration based upon the linear correlation, providing an extended record of DBC concentration. The extended DBC record was coupled with daily discharge data from the six rivers to estimate riverine DBC loads using the LOADEST modeling program. The six rivers studied cover 53% of the pan-Arctic watershed and exported 1.5 ± 0.1 million tons of DBC per year. Scaling up to the full area of the pan-Arctic watershed, we estimate that Arctic rivers carry 2.8 ± 0.3 million tons of DBC from land to the Arctic Ocean each year. This equates to ~8% of Arctic river DOC export, slightly less than indicated by the simpler DBC vs DOC correlation-based estimate. Riverine discharge is predicted to increase in a warmer Arctic. DBC export was positively correlated with river runoff, suggesting that the export of soil BC to the Arctic Ocean is likely to increase as the Arctic warms.

  12. Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers

    Science.gov (United States)

    Stubbins, Aron; Spencer, Robert; Mann, Paul; Holmes, R.; McClelland, James; Niggemann, Jutta; Dittmar, Thorsten

    2015-10-01

    Wildfires have produced black carbon (BC) since land plants emerged. Condensed aromatic compounds, a form of BC, have accumulated to become a major component of the soil carbon pool. Condensed aromatics leach from soils into rivers, where they are termed dissolved black carbon (DBC). The transport of DBC by rivers to the sea is a major term in the global carbon and BC cycles. To estimate Arctic river DBC export, 25 samples collected from the six largest Arctic rivers (Kolyma, Lena, Mackenzie, Ob’, Yenisey and Yukon) were analyzed for dissolved organic carbon (DOC), colored dissolved organic matter (CDOM), and DBC. A simple, linear regression between DOC and DBC indicated that DBC accounted for 8.9 ± 0.3% DOC exported by Arctic rivers. To improve upon this estimate, an optical proxy for DBC was developed based upon the linear correlation between DBC concentrations and CDOM light absorption coefficients at 254 nm (a254). Relatively easy to measure a254 values were determined for 410 Arctic river samples between 2004 and 2010. Each of these a254 values was converted to a DBC concentration based upon the linear correlation, providing an extended record of DBC concentration. The extended DBC record was coupled with daily discharge data from the six rivers to estimate riverine DBC loads using the LOADEST modeling program. The six rivers studied cover 53% of the pan-Arctic watershed and exported 1.5 ± 0.1 million tons of DBC per year. Scaling up to the full area of the pan-Arctic watershed, we estimate that Arctic rivers carry 2.8 ± 0.3 million tons of DBC from land to the Arctic Ocean each year. This equates to ~8% of Arctic river DOC export, slightly less than indicated by the simpler DBC vs DOC correlation-based estimate. Riverine discharge is predicted to increase in a warmer Arctic. DBC export was positively correlated with river runoff, suggesting that the export of soil BC to the Arctic Ocean is likely to increase as the Arctic warms.

  13. Street characteristics and traffic factors determining road users' exposure to black carbon.

    Science.gov (United States)

    Dons, Evi; Temmerman, Philip; Van Poppel, Martine; Bellemans, Tom; Wets, Geert; Int Panis, Luc

    2013-03-01

    Many studies nowadays make the effort of determining personal exposure rather than estimating exposure at the residential address only. While intra-urban air pollution can be modeled quite easily using interpolation methods, estimating exposure in transport is more challenging. The aim of this study is to investigate which factors determine black carbon (BC) concentrations in transport microenvironments. Therefore personal exposure measurements are carried out using portable aethalometers, trip diaries and GPS devices. More than 1500 trips, both by active modes and by motorized transport, are evaluated in Flanders, Belgium. GPS coordinates are assigned to road segments to allow BC concentrations to be linked with trip and road characteristics (trip duration, degree of urbanization, road type, traffic intensity, travel speed and road speed). Average BC concentrations on highways (10.7μg/m(3)) are comparable to concentrations on urban roads (9.6μg/m(3)), but levels are significantly higher than concentrations on rural roads (6.1μg/m(3)). Highways yield higher BC exposures for motorists compared to exposure on major roads and local roads. Overall BC concentrations are elevated at lower speeds (cyclists and pedestrians the range in BC exposure is smaller and models are less predictive; for active modes exposure seems to be influenced by timing and degree of urbanization only.

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

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL

    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

  15. Intercomparison of thermal and optical measurement methods for elemental carbon and black carbon at an urban location.

    Science.gov (United States)

    Hitzenberger, R; Petzold, A; Bauer, H; Ctyroky, P; Pouresmaeil, P; Laskus, L; Puxbaum, H

    2006-10-15

    Despite intensive efforts during the past 20 years, no generally accepted standard method exists to measure black carbon (BC) or elemental carbon (EC). Data on BC and EC concentrations are method specific and can differ widely (e.g. Schmid et al., 2001, ten Brink et al., 2004). In this study, a comprehensive set of methods (both optical and thermal) is compared. Measurements were performed under urban background conditions in Vienna, Austria, a city heavily impacted by diesel emissions. Filter and impactor samples were taken during 3 weeks in summer 2002 and analyzed for EC with thermal methods: a modified Cachier method (Cachier et al., 1989), a thermal-optical method (Schmid et al., 2001), and the VDI method (VDI, 1996); for BC with optical methods: a filter transmission method and the integrating sphere method (Hitzenberger et al., 1996); and for total carbon (TC) with a combustion method (Puxbaum and Rendl, 1983). The online methods aethalometer (Hansen et al., 1984) and the multiangle absorption photometer MAAP (Petzold et al., 2002) to measure BC were also used. The average values of BC and EC obtained with the methods agreed within their standard deviations. A conversion table was set up to allow comparisons between data measured elsewhere under urban background conditions (with similar source characteristics) with different instruments. An approach to estimate the absorption coefficient from attenuation data is derived so that existing records of aethalometer data in urban environments may be used to obtain also the absorption coefficients.

  16. Modelling of Black and Organic Carbon Variability in the Northern Hemisphere

    Science.gov (United States)

    Kurganskiy, Alexander; Nuterman, Roman; Mahura, Alexander; Kaas, Eigil; Baklanov, Alexander; Hansen Sass, Bent

    2016-04-01

    Black and organic carbon as short-lived climate forcers have influence on air quality and climate in Northern Europe and Arctic. Atmospheric dispersion, deposition and transport of these climate forcers from remote sources is especially difficult to model in Arctic regions due to complexity of meteorological and chemical processes and uncertainties of emissions. In our study, the online integrated meteorology-chemistry/aerosols model Enviro-HIRLAM (Environment - High Resolution Limited Area Model) was employed for evaluating spatio-temporal variability of black and organic carbon aerosols in atmospheric composition in the Northern Hemisphere regions. The model setup included horizontal resolution of 0.72 deg, time step of 450 sec, 6 h meteorological surface data assimilation, 1 month spin-up; and model was run for the full year of 2010. Emissions included anthropogenic (ECLIPSE), shipping (AU_RCP&FMI), wildfires (IS4FIRES), and interactive sea salt, dust and DMS. Meteorological (from IFS at 0.75 deg) and chemical (from MACC Reanalysis at 1.125 deg) boundary conditions were obtained from ECMWF. Annual and month-to-month variability of mean concentration, accumulated dry/wet and total deposition fluxes is analyzed for the model domain and selected European and Arctic observation sites. Modelled and observed BC daily mean concentrations during January and July showed fair-good correlation (0.31-0.64) for stations in Germany, UK and Italy; however, for Arctic stations (Tiksi, Russia and Zeppelin, Norway) the correlations were negative in January, but higher correlations and positive (0.2-0.7) in July. For OC, it varied 0.45-0.67 in January and 0.19-0.57 in July. On seasonal scale, during both summer and winter seasons the BC and OC correlations are positive and higher for European stations compared with Arctic. On annual scale, both BC and OC correlations are positive and vary between 0.4-0.6 for European stations, and these are smoothed to negligible values for Arctic

  17. The Effectiveness of the Regulatory Regime for Black Carbon Mitigation in the Arctic

    Directory of Open Access Journals (Sweden)

    Daria Shapovalova

    2016-11-01

    Full Text Available In addition to being a hazardous air pollutant, Black Carbon is the second-largest contributor to Arctic warming. Its mitigation is being addressed at the international regulatory level by the Arctic Council and the Convention on Long-Range Transboundary Air Pollution (CLRTAP. Whilst the Convention and its protocols are binding documents, the Black Carbon regulation under their framework appears to have ‘soft law’ characteristics. At the same time, the voluntary Black Carbon and Methane Framework, adopted by the Arctic Council, demonstrates positive compliance and follow-up dynamics compared to earlier norm-creating attempts. This paper argues that the nature of the norm (binding or non-binding is not the decisive factor regarding effective implementation in the Arctic region. Current efforts to mitigate Black Carbon by means of a non-binding Arctic Council Black Carbon and Methane Framework represent an improvement in the Council's normative function and may have more effect on the behaviour of Arctic States than relevant provisions under the Gothenburg Protocol to the CLRTAP. To support this argument, the first section presents an overview of the Arctic Council as an actor in Arctic policy-making. It then provides an assessment of current efforts to combat Black Carbon carried out by the Arctic Council and the CLRTAP.

  18. The nature of carbon material in the black shale rock mass of Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, L.G.

    1981-01-01

    Carbon material is closely tied to ores of various origin lying in the carbon (black shale) rock masses of Kazakhastan. The nature of the carbon material in several gold fields is closely examined. Shungite, its paragenesis with ore materials and its role in the carbon and ore material processes, is described. The accumulation of shungite in zones determined to consist of ores, is looked at in terms of prospecting criteria.

  19. Stormwater and fire as sources of black carbon nanoparticles to Lake Tahoe.

    Science.gov (United States)

    Bisiaux, Marion M; Edwards, Ross; Heyvaert, Alan C; Thomas, James M; Fitzgerald, Brian; Susfalk, Richard B; Schladow, S Geoffrey; Thaw, Melissa

    2011-03-15

    Emitted to the atmosphere through fire and fossil fuel combustion, refractory black carbon nanoparticles (rBC) impact human health, climate, and the carbon cycle. Eventually these particles enter aquatic environments, where they may affect the fate of other pollutants. While ubiquitous, the particles are still poorly characterized in freshwater systems. Here we present the results of a study determining rBC in waters of the Lake Tahoe watershed in the western United States from 2007 to 2009. The study period spanned a large fire within the Tahoe basin, seasonal snowmelt, and a number of storm events, which resulted in pulses of urban runoff into the lake with rBC concentrations up to 4 orders of magnitude higher than midlake concentrations. The results show that rBC pulses from both the fire and urban runoff were rapidly attenuated suggesting unexpected aggregation or degradation of the particles. We find that those processes prevent rBC concentrations from building up in the clear and oligotrophic Lake Tahoe. This rapid removal of rBC soon after entry into the lake has implications for the transport of rBC in the global aquatic environment and the flux of rBC from continents to the global ocean.

  20. Size-selected black carbon mass distributions and mixing state in polluted and clean environments of northern India

    Science.gov (United States)

    Raatikainen, Tomi; Brus, David; Hooda, Rakesh K.; Hyvärinen, Antti-Pekka; Asmi, Eija; Sharma, Ved P.; Arola, Antti; Lihavainen, Heikki

    2017-01-01

    We have measured black carbon properties by using a size-selected single-particle soot photometer (SP2). The measurements were conducted in northern India at two sites: Gual Pahari is located at the Indo-Gangetic Plain (IGP) and Mukteshwar at the Himalayan foothills. Northern India is known as one of the absorbing aerosol hot spots, but detailed information about absorbing aerosol mixing state is still largely missing. Previous equivalent black carbon (eBC) mass concentration measurements are available for this region, and these are consistent with our observations showing that refractory black carbon (rBC) concentrations are about 10 times higher in Gual Pahari than those at Mukteshwar. Also, the number fraction of rBC-containing particles is higher in Gual Pahari, but individual rBC-containing particles and their size distributions are fairly similar. These findings indicate that particles at both sites have similar local and regional emission sources, but aerosols are also transported from the main source regions (IGP) to the less polluted regions (Himalayan foothills). Detailed examination of the rBC-containing particle properties revealed that they are most likely irregular particles such as fractal aggregates, but the exact structure remains unknown.

  1. Probing Black Carbon-containing Particle Microphysics with the Single-Particle Soot Photometer (SP2)

    Science.gov (United States)

    Sedlacek, A. J.; Lewis, E. R.; Onasch, T. B.; Lambe, A. T.; Davidovits, P.; Kleinman, L. I.

    2012-12-01

    Knowledge of the structure and mixing state of black-carbon containing particles is important for calculating their radiative forcing and provides insight into their source and life cycle. Recently analysis of black carbon-containing particles has demonstrated that for a fraction of such particles, the black carbon may reside on or near the surface of the particle as opposed to the traditional core-shell configuration typically assumed in which the black carbon core is surrounded by a shell of non-refractory material. During the DOE-sponsored Aerosol Lifecycle field campaign held in summer, 2011 at Brookhaven National Laboratory on Long Island, NY, episodes were encountered in which a high fraction of particles containing black carbon had such configurations, and these episodes corresponded to air masses that contained biomass burning plumes (Sedlacek et al., 2012). Subsequent analysis found other episodes in field campaigns in Colorado and California in which high fractions this configuration corresponded to biomass burning plumes. In an effort to evaluate this interpretation and explore formation mechanisms, a series of laboratory-based experiments examining the coagulation of regal black (surrogate for collapsed soot) with model non-refractory coatings [dioctyl sebacate (surrogate for organic aerosols with liquid-like character) and deliquesced ammonium sulfate (solid)] were carried out. The results of these experiments and their potential implications on black carbon radiative forcing will be discussed. Sedlacek, III, Arthur, E. R. Lewis, L. I. Kleinman, J. Xu and Q. Zhang (2012), Determination of and Evidence for Non-core-shell structure of particles containing black carbon using the single particle soot photometer (SP2). Geophys. Res. Lett., 39 L06802, doi:10.1029/2012GL050905

  2. Influence of the carbon dioxide concentration on the resistance to carbonation of concrete

    NARCIS (Netherlands)

    Visser, J.H.M.

    2013-01-01

    Carbonation of concrete at ambient CO2 concentration is a slow process. This makes the testing of the resistance of concrete against carbonation often too slow to be applicable for service life assessments of new structures. Raising the CO2-concentration will accelerate the test but the validity of

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

    Science.gov (United States)

    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.

  4. Exposure to ultrafine particles and black carbon in diesel-powered commuter trains

    Science.gov (United States)

    Jeong, Cheol-Heon; Traub, Alison; Evans, Greg J.

    2017-04-01

    Ultrafine particle (UFP), black carbon (BC) and lung deposited surface area (LDSA) concentrations measured during 43 trips on diesel-powered commuter trains revealed elevated exposures under some conditions. When the passenger coaches were pulled by a locomotive, the geometric mean concentrations of UFP, LDSA, and BC were 18, 10, and 6 times higher than the exposure levels when the locomotive pushed the coaches, respectively. In addition, UFP, LDSA, and BC concentrations in pull-trains were 5, 3, and 4 times higher than concentrations measured while walking on city sidewalks, respectively. Exposure to these pollutants was most elevated in the coach located closest to the locomotive: geometric means were 126,000 # cm-3 for UFP, 249 μm2 cm-3 for LDSA, and 17,800 ng m-3 of BC; these concentrations are much higher than those previously reported for other modes of public transportation. Markedly high levels of diesel exhaust are present in passenger trains powered by diesel locomotives operated in pull-mode. Thus, it is recommended that immediate steps be taken to evaluate, and where needed, mitigate exposure in diesel-powered passenger trains, both commuter and inter-city.

  5. Black carbon aerosols and their radiative properties in the Pearl River Delta region

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1―14.8 μg·m-3 and the concentration decreases by about 1 μg·m-3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m-3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher

  6. Black carbon aerosols and their radiative properties in the Pearl River Delta region

    Institute of Scientific and Technical Information of China (English)

    WU Dui; MAO JieTai; DENG XueJiao; TIE XueXi; ZHANG YuanHang; ZENG LiMin; LI Fei; TAN HaoBo; BI XueYan; HUANG XiaoYing; CHEN Jing; DENG Tao

    2009-01-01

    The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main resuits are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1-14.8 pg. m-3 and the concentration decreases by about 1 μg. m-3 in average over the four years; It is higher in the dry season with a multi-year mean of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, end a 4-year mean is 8.4 pg. m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 66% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of

  7. NONLINEAR CURRENT-VOLTAGE CHARACTERISTICS OF CONDUCTIVE POLYETHYLENE COMPOSITES WITH CARBON BLACK FILLED PET MICROFIBRILS

    Institute of Scientific and Technical Information of China (English)

    Qian-ying Chen; Jing Gao; Kun Dai; Huan Pang; Jia-zhuang Xu; Jian-hua Tang; Zhong-ming Li

    2013-01-01

    Current-voltage electrical behavior of in situ microfibrillar carbon black (CB)/poly(ethylene terephthalate)(PET)/polyethylene (PE) (m-CB/PET/PE) composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field.The current-voltage (Ⅰ-Ⅴ) curves exhibited nonlinearity beyond a critical value of voltage.The dynamic random resistor network (DRRN) model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites.Macroscopic nonlinearity originated from the interracial interactions between CB/PET micro fibrils and additional conduction channels.Combined with the special conductive networks,an illustration was proposed to interpret the nonlinear Ⅰ-Ⅴ characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET microfibers intersections.

  8. Research on properties of carbon black/polypropylene composites by dynamic injection molding

    Science.gov (United States)

    Wu, Ming-Chun; He, Guang-Jian; Huang, Zhao-Xia; Zhou, Li-Ying; He, He-Zhi

    2016-03-01

    Polymer composites filled with conductive carbon black (CB) are gaining popularity for electromagnetic shielding applications. Dynamic injection molding method was adopted to study the influences of vibration force field on electrical properties of polypropylene/CB composites. The results showed that the percolation phenomenon of conductivity of composites occurred at 15wt% and the calculated SE was positive correlated with the variation trend of conductivity. The calculated SE of composite was more than 30dB at a CB concentration of 30wt%, which could obtain good shielding effects. The result could offer optimum vibration parameters for producing electromagnetic shielding composites by respectively changing the amplitudes and frequencies of the vibration force field.

  9. Dissolved Black Carbon in the Southern Ocean along CLIVAR section I6S

    Science.gov (United States)

    Paeng, J.; Dittmar, T.

    2008-12-01

    Thermogenic matter ("black carbon", BC) is abundant in the environment. BC is produced during catagenesis in earth's crust and is also a residue of fossil fuel and biomass burning. Because of its refractory character, BC accumulates in soils and sediments and sequesters carbon from active cycles. Previous studies found indications that BC might be a significant component also in marine dissolved organic matter (DOM). However, the available information on black carbon in DOM is extremely rare up to now. The objective of this study is to quantify BC in marine DOM and identify the source and dynamics of dissolved BC for a major oceanic region. Detailed depth profiles were sampled along 30º E from South Africa to Antarctica at 1º intervals on CLIVAR section I6S. Dissolved BC was isolated from approximately 250 seawater samples via a new solid phase extraction method. Fused aromatic ring systems as a molecular tracer for BC were quantified in these samples. For this purpose, the samples were oxidized with nitric acid and the reaction products of fused ring systems analyzed as benzene-polycarboxylic acids with HPLC. BC concentrations were very stable throughout the water column and along the North-South section, ranging between 500 and 700 nM BC. The molecular composition of benzene-polycarboxylic acids indicates a relatively small number of fused aromatic rings per molecule. Similar structures were observed preciously in riverine and also petroleum-derived DOM. The homogenous distribution of BC in all water masses indicates conservative behavior of BC in the ocean, and turnover rates which are far longer than oceanic turnover rates. The stable character of dissolved BC and its abundance in the ocean has major implications for our understanding of global biogeochemical cycles.

  10. End of the "Little Ice Age" in the Alps not forced by industrial black carbon

    Science.gov (United States)

    Sigl, Michael; Osmont, Dimtri; Gabrieli, Jacopo; Barbante, Carlo; Schwikowski, Margit

    2016-04-01

    Light absorbing aerosols present in the atmosphere and cryosphere play an important role in the climate system. Their presence in ambient air and snow changes radiative properties of these media, thus contributing to increased atmospheric warming and snowmelt. High spatio-temporal variability of aerosol concentrations in these media and a shortage of long-term observations contribute to large uncertainties in properly assigning the climate effects of these aerosols through time. 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. Radiative forcing by increasing deposition of industrial black carbon to snow has been suggested as the main driver of the abrupt glacier retreats in the Alps (Painter et al. 2012). Basis for this hypothesis were model simulations using ice-core measurements of elemental carbon at low temporal resolution from two ice cores in the Alps. Here we present sub-annually resolved, well replicated ice-core measurements of refractory black carbon (rBC; using a SP2 soot photometer), mineral dust (Fe, Ca), biomass burning (NH4, K) and distinctive industrial pollution tracers (Bi, Pb, SO4) from an ice core in the Alps covering the past 250 years. These reconstructions allow to precisely compare the timing of observed acceleration of glacier melt in the mid-19th century with that of the increase of soot deposition on ice-sheets caused by the industrialization of Western Europe. Our study suggests that at the time when European rBC emission rates started to significantly increase Alpine glaciers have already experienced more than 70% of their total 19th century length reduction. Industrial BC emissions can therefore not been considered as the primary forcing of the rapid deglaciation at the end of the Little Ice Age in the Alps. References: Painter, T. H., M. G. Flanner, G. Kaser, B. Marzeion, R. A. VanCuren, and W. Abdalati (2013), End of the Little Ice

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

    Science.gov (United States)

    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.

  12. Chemical and biological oxidative effects of carbon black nanoparticles.

    Science.gov (United States)

    Koike, Eiko; Kobayashi, Takahiro

    2006-11-01

    Several studies show that ultrafine particles have a larger surface area than coarse particles, thus causing a greater inflammatory response. In this study, we investigated chemical and biological oxidative effects of nanoparticles in vitro. Carbon black (CB) nanoparticles with mean aerodynamic diameters of 14, 56, and 95nm were examined. The innate oxidative capacity of the CB nanoparticles was measured by consumption of dithiothreitol (DTT) in cell-free system. The expression of heme oxygenase-1 (HO-1) in rat alveolar type II epithelial cell line (SV40T2) and alveolar macrophages (AM) exposed to CB nanoparticles was measured by ELISA. DTT consumption of 14nm CB was higher than that of other CB nanoparticles having the same particle weight. However, DTT consumption was directly proportional to the particle surface area. HO-1 protein in SV40T2 cells was significantly increased by the 14nm and 56nm CB, however, 95nm CB did not affect. HO-1 protein in AM was significantly increased by the 14, 56, and 95nm CB. The increase in HO-1 expression was diminished by N-acetyl-l-cysteine (NAC) treatment of each CB nanoparticles before exposure although the difference between the effects of NAC-treated and untreated 14nm CB did not achieve significant. In conclusion, CB nanoparticles have innate oxidative capacity that may be dependent on the surface area. CB nanoparticles can induce oxidative stress in alveolar epithelial cells and AM that is more prominent with smaller particles. The oxidative stress may, at least partially, be mediated by surface function of particles.

  13. Radiative absorption enhancement from coatings on black carbon aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xinjuan; Wang, Xinfeng; Yang, Lingxiao [Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Chen, Bing, E-mail: bingchen@sdu.edu.cn [Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Chen, Jianmin, E-mail: jmchen@sdu.edu.cn [Environmental Research Institute, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Andersson, August; Gustafsson, Örjan [Department of Environmental Science and Analytical Chemistry (ACES) and the Bolin Centre for Climate Research, Stockholm University, SE-10691 Stockholm (Sweden)

    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 ± 0.8 m{sup 2}g{sup −1} was enhanced to 9.6 ± 1.8 m{sup 2}g{sup −1} at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (E{sub MAC}) 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 E{sub MAC} of 2.25 ± 0.55, and sulfates were primary drivers of the enhanced BC absorption. - Highlights: • A method was developed to remove coatings surrounding BC in ambient aerosols. • The MAC of decoated BC of 4.4 was enhanced to 9.6 m{sup 2}g{sup −1} for ambient BC aerosols. • BC radiative forcing in the ambient atmosphere was enhanced by a factor of ~ 2. • BC absorption enhancement peaked in day time driven by secondary sulfate.

  14. Central Asian supra-glacier snow melt enhanced by anthropogenic black carbon

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Farinotti, Daniel; Zhang, Qianggong; Guo, Junming; Li, Yang; Lawrence, Mark; Schwikowski, Margit

    2016-04-01

    In Central Asia, more than 60 % of the population depends on water stored in glaciers and mountain snow. Densely populated areas near lower-lying mountain ranges are particularly vulnerable and a recent study showed that the region might lose 50 % of its glacier mass by 2050. While temperature, precipitation and dynamic processes are key drivers of glacial change, deposition of light absorbing impurities such as mineral dust and black carbon can lead to accelerated melting through surface albedo reduction. Here, we discuss the origin of deposited mineral dust and black carbon and their impacts on albedo change and snow melt. 218 snow samples were taken on 4 glaciers, Abramov (Pamir), Suek, Glacier No. 354 and Golubin (Tien Shan), representing deposition between summer 2012 and 2014. They were analyzed for elemental carbon, mineral dust and iron among other parameters. We find the elemental carbon concentration to be at the higher end of the range reported for neighboring mountain ranges between 70 and 502 ng g-1 (interquartile range). To investigate the origin of the snow impurities, we used a Lagrangian particle dispersion model, LAGRANTO. Back trajectory ensembles of 40 members with varied starting points to capture the meteorological spread were released every 6 hours for the covered period at all sites. "Footprints" were calculated and combined with emission inventories to estimate the relative contribution of anthropogenic and natural BC to deposited aerosol on the glaciers. We find that more than 94 % of BC is of anthropogenic origin and the major source region is Central Asia followed by the Middle East. Further exploring the implications of mineral dust and BC deposition, we calculate the snow albedo reduction with the Snow-Ice-Aerosol-Radiative model (SNICAR). Even though mineral dust concentrations were up to a factor of 50 higher than BC concentrations, BC dominates the albedo reduction. Using these results we calculate the snow melt induced by

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

    Science.gov (United States)

    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

  16. Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE

    Directory of Open Access Journals (Sweden)

    M. Yang

    2009-03-01

    Full Text Available Black carbon, brown carbon, and mineral dust are three of the most important light absorbing aerosols. Their optical properties differ greatly and are distinctive functions of the wavelength of light. Most optical instruments that quantify light absorption, however, are unable to distinguish one type of absorbing aerosol from another. It is thus instructive to separate total absorption from these different light absorbers to gain a better understanding of the optical characteristics of each aerosol type. During the EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment campaign near Beijing, we measured light scattering using a nephelometer, and light absorption using an aethalometer and a particulate soot absorption photometer. We also measured the total mass concentrations of carbonaceous (elemental and organic carbon and inorganic particulates, as well as aerosol number and mass distributions. We were able to identify periods during the campaign that were dominated by dust, biomass burning, fresh (industrial chimney plumes, other coal burning pollution, and relatively clean (background air for Northern China. Each of these air masses possessed distinct intensive optical properties, including the single scatter albedo and Ångstrom exponents. Based on the wavelength-dependence and particle size distribution, we apportioned total light absorption to black carbon, brown carbon, and dust; their mass absorption efficiencies at 550 nm were estimated to be 9.5, 0.5 (a lower limit value, and 0.03 m2/g, respectively. While agreeing with the common consensus that black carbon is the most important light absorber in the mid-visible, we demonstrated that brown carbon and dust could also cause significant absorption, especially at shorter wavelengths.

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

    Science.gov (United States)

    Clack, Herek L

    2012-07-03

    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.

  18. Impact of California's Air Pollution Laws on Black Carbon and their Implications for Direct Radiative Forcing

    Science.gov (United States)

    Bahadur, R.; Feng, Y.; Russell, L. M.; Ramanathan, V.

    2010-12-01

    We examine the temporal and the spatial trends in the concentrations of black carbon (BC) - recorded by the IMPROVE monitoring network for the past 20 years - in California. Annual average BC concentrations in California have decreased by about 50% from 0.46 μg m-3 in 1989 to 0.24 μgm-3 in 2008 compared to a corresponding reductions in diesel BC emissions (also about 50%) from a peak of 0.013 Tg Yr-1 in 1990 to 0.006 Tg Yr-1 by 2008. We attribute the observed negative trends to the deployment of diesel particulate filters. Our conclusion that the reduction in diesel emissions is the primary cause of the observed BC reduction is also substantiated by a significant decrease in the ratio of BC to non-BC aerosols. The absorption efficiency of aerosols at visible wavelengths - determined from the observed scattering coefficient and the observed BC - also decreased by about 50% leading to a model-inferred negative direct radiative forcing (a cooling effect) of -1.4 Wm-2 (±60%) over California. Figure 1 (a) Annual means of measured Black Carbon (left axis) and BC fossil fuel emissions (right axis) in California from 1985 to 2008. Error bars correspond to standard deviation between measurements at each station. Dashed lines indicate a linear fit. Aerosol measurements from the IMPROVE network, emission inventories from (1) CARB, (2) [Ito and Penner, 2005] (b) Annual means of BC measured in Southern (South of 35 N), Northern (North of 38 N), and Central California (c) Annual means of measured Sulfate, Nitrate, and OC from IMPROVE network.

  19. Real-time indoor and outdoor measurements of black carbon at primary schools

    Science.gov (United States)

    Reche, C.; Rivas, I.; Pandolfi, M.; Viana, M.; Bouso, L.; Àlvarez-Pedrerol, M.; Alastuey, A.; Sunyer, J.; Querol, X.

    2015-11-01

    Epidemiological and toxicological studies have demonstrated the association between Black Carbon in indoor and outdoor air and the occurrence of health risks. Data on air quality in schools is of special interest, as children are more vulnerable to health hazards. In this context, indoor and outdoor measurements of real-time Equivalent Black Carbon (EBC) were collected at 39 primary schools located in Barcelona (Spain), with classrooms naturally ventilated under warm weather conditions. A main contribution of road traffic emissions to indoor and outdoor EBC levels was evidenced through different approaches. Simultaneous measurements of EBC levels at schools under different traffic conditions revealed concentrations by 30-35% higher at schools exposed to higher vehicles intensities. Moreover, a significant correlation was obtained between average outdoor EBC levels at different districts of the city and the percentage of surface area in each district used for the road network (R2 = 0.61). Higher indoor than outdoor levels were recorded at some instances when the indoor sampling location was relatively closer to road traffic, even under low outdoor temperatures. Indeed, the average indoor/outdoor EBC ratios for each school correlate moderately between campaigns in spite of significant differences in temperature between sampling periods. These two facts highlight the strong dependency of the EBC levels on the distance to traffic. The peaks of exposure inside the classrooms seemed to be determined by outdoor concentrations, as shown by the parallelism between indoor and outdoor mean EBC daily cycles and the similar contribution of traffic rush hours to indoor and outdoor daily mean levels. The airtightness of the classroom was suggested as the responsible for the indoor/outdoor ratios of EBC higher than 1 recorded at nights.

  20. Modeling water column partitioning of polychlorinated biphenyls to natural organic matter and black carbon.

    Science.gov (United States)

    Greene, Richard W; Di Toro, Dominic M; Farley, Kevin J; Phillips, Kathy L; Tomey, Cynthia

    2013-06-18

    High volume in situ surface water samples were collected from a tidal tributary of the Delaware Estuary using an Infiltrex sampling system equipped with a 1 μm particle filter and a XAD-2 resin column. Particulate and dissolved phase polychlorinated biphenyl (PCB) congeners were analyzed using high resolution gas chromatography/high resolution mass spectrometry to obtain detection levels in the femtograms per liter range. The data were fit to a four-phase equilibrium partitioning model including freely dissolved PCB, PCB bound to particulate organic carbon (POC), PCB bound to dissolved organic carbon (DOC), and PCB bound to black carbon (BC). Isotherms were assumed to be linear for POC and DOC and nonlinear for BC. The partition coefficient between BC and dissolved PCB was assumed to depend on the dihedral angle between the phenyl rings. Following parameter optimization, the correlation coefficient between the log of the modeled and measured apparent distribution coefficient Kp,app was 0.94, and the RMSE was 0.189 log units. Including BC in the model reduces the dissolved PCB phase concentration in the water column for all congeners, especially for the non-ortho and mono-ortho substituted congeners.

  1. Quantification of extraneous carbon during compound specific radiocarbon analysis of black carbon.

    Science.gov (United States)

    Ziolkowski, Lori A; Druffel, Ellen R M

    2009-12-15

    Radiocarbon ((14)C) is a radioactive isotope that is useful for determining the age and cycling of carbon-based materials in the Earth system. Compound specific radiocarbon analysis (CSRA) provides powerful insight into the turnover of individual components that make up the carbon cycle. Extraneous or nonspecific background carbon (C(ex)) is added during sample processing and subsequent isolation of CSRA samples. Here, we evaluate the quantity and radiocarbon signature of C(ex) added from two sources: preparative capillary gas chromatography (PCGC, C(PCGC)) and chemical preparation of CSRA of black carbon samples (C(chemistry)). We evaluated the blank directly using process blanks and indirectly by quantifying the difference in the isotopic composition between processed and unprocessed samples for a range of sample sizes. The direct and indirect assessment of C(chemistry+PCGC) agree, both in magnitude and radiocarbon value (1.1 +/- 0.5 microg of C, fraction modern = 0.2). Half of the C(ex) is introduced before PCGC isolation, likely from coeluting compounds in solvents used in the extraction method. The magnitude of propagated uncertainties of CSRA samples are a function of sample size and collection duration. Small samples collected for a brief amount of time have a smaller propagated (14)C uncertainty than larger samples collected for a longer period of time. CSRA users are cautioned to consider the magnitude of uncertainty they require for their system of interest, to frequently evaluate the magnitude of C(ex) added during sampling processing, and to avoid isolating samples < or = 5 microg of carbon.

  2. On-road black carbon instrument intercomparison and aerosol characteristics by driving environment

    Science.gov (United States)

    Holder, Amara L.; Hagler, Gayle S. W.; Yelverton, Tiffany L. B.; Hays, Michael D.

    2014-05-01

    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 instruments (Single Particle Soot Photometer, Photo-Acoustic Soot Spectrometer, and Aethalometer) for high time resolution mobile measurements, capable of mapping spatial gradients. All instruments were highly correlated at high time resolution (r2 = 0.80-0.89 at a 2-s resolution), however the slope ranged from 0.52 to 1.03, with the Single Particle Soot Photometer (SP2) consistently reporting the lowest BC concentrations. BC and ultrafine particle (UFP) concentrations were two-fold higher on the highway compared to surrounding roads with lower traffic counts. The BC size distribution had a mass median diameter of approximately 120 nm, which was smaller and less coated than aged urban BC. Mean UFP and BC concentrations were 2 and 1.4 times greater, respectively, during free flowing traffic on the highway compared with times when there was stop-and-go congestion, providing evidence that transit time is not a good predictor of BC or UFP exposure.

  3. Black carbon sources constrained by observations in the Russian high Arctic.

    Science.gov (United States)

    Popovicheva, Olga Borsovna; Evangeliou, Nikolaos; Eleftheriadis, Konstantinos; Kalogridis, Athina Cerise; Movchan, Vadim Vadimovich; Sitnikov, Nikolay; Eckhardt, Sabine; Makshtas, Alexander; Stohl, Andreas

    2017-02-24

    Understanding the role of short-lived climate forcers like black carbon (BC) at high northern latitudes in climate change is hampered by the scarcity of surface observations in the Russian Arctic. In this study, highly time resolved Equivalent BC (EBC) measurements during a ship campaign in the White, Barents and Kara Seas in October 2015 are presented. The measured EBC concentrations are compared with BC concentrations simulated with a Lagrangian particle dispersion model coupled with a recently completed global emission inventory to quantify the origin of the Arctic BC. EBC showed increased values (100-400 ng m-3) in the Kara Strait, Kara Sea, and Kola Peninsula, and an extremely high concentration (1000 ng m-3) in the White Sea. Assessment of BC origin throughout the expedition showed that gas flaring emissions from the Yamal/Khanty-Mansiysk and Nenets/Komi regions contributed the most when the ship was close to the Kara Strait, north of 70˚N. Near Arkhangelsk (White Sea), biomass burning in mid-latitudes, surface transportation, and residential and commercial combustion from Central and Eastern Europe were found to be important BC sources. The model reproduced observed EBC concentrations efficiently, building credibility in the emission inventory for BC emissions at high northern latitudes.

  4. Quantification and radiocarbon source apportionment of black carbon in atmospheric aerosols using the CTO-375 method

    Science.gov (United States)

    Zencak, Zdenek; Elmquist, Marie; Gustafsson, Örjan

    To make progress towards linking the atmosphere and biogeosphere parts of the black carbon (BC) cycle, a chemothermal oxidation method (CTO-375), commonly applied for isolating BC from complex geomatrices such as soils, sediments and aquatic particles, was applied to investigate the BC also in atmospheric particles. Concentrations and 14C-based source apportionment of CTO-375 based BC was established for a reference aerosol (NIST RM-8785) and for wintertime aerosols collected in Stockholm and in a Swedish background area. The results were compared with thermal-optical (OC/EC) measurements. For NIST RM-8785, a good agreement was found between the BC CTO-375 concentration and the reported elemental carbon (EC) concentration measured by the "Speciation Trends Network—National Institute of Occupational Safety and Health" method (EC NIOSH) with BC CTO-375 of 0.054±0.002 g g -1 and EC NIOSH of 0.067±0.008 g g -1. In contrast, there was an average factor of ca. 20 difference between BC CTO-375 and EC NIOSH for the ambient Scandinavian wintertime aerosols, presumably reflecting a combination of BC CTO-375 isolating only the recalcitrant soot-BC portion of the BC continuum and the EC NIOSH metric inadvertently including some intrinsically non-pyrogenic organic matter. Isolation of BC CTO-375 with subsequent off-line radiocarbon analysis yielded fraction modern values (fM) for total organic carbon (TOC) of 0.93 (aerosols from a Swedish background area), and 0.58 (aerosols collected in Stockholm); whereas the fM for BC CTO-375 isolates were 1.08 (aerosols from a Swedish background area), and 0.87 (aerosols collected in Stockholm). This radiocarbon-based source apportionment suggests that contribution from biomass combustion to cold-season atmospheric BC CTO-375 in Stockholm was 70% and in the background area 88%.

  5. Study on Behavior of Carbon Reduction of Monazite Concentrate

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The behavior of monazite concentrate reduced by carbon, especially the decomposed procedure of rare earth phosphates, was investigated by X-ray diffraction , electron probe, TG method and chemical analysis. The results show that rare earth phosphates in monazite concentrate can be reduced to their oxides, among them the decomposition processes of cerium phosphate are not in step with lanthanum phosphate, neodymium phosphate and so on, and the phosphorus was volatilized into air in simple form.

  6. Relationship between Black Carbon and heavy traffic in São Paulo, Brazil

    Science.gov (United States)

    Miranda, R. M.; Perez-Martinez, P.; Ribeiro, F. N. D.; Andrade, M. D. F.

    2015-12-01

    Carbonaceous aerosols play an important role in air quality, human health and global climate change. Black Carbon (BC) can be considered the most efficient light absorber in the visible spectrum and is mainly found in the fine fraction of aerosol. Typically is emitted by incomplete combustion of fossil fuels related to traffic, industrial processes and biomass burning. São Paulo Metropolitan Area (SPMA) with more than 19 million inhabitants, 7 million vehicles, as well as the major industrial and technological park of the country, has high concentrations of air pollutants, especially in the winter and vehicles are considered the principal source of particles emitted to the atmosphere. Since November 2014, Black Carbon and PM2.5 are being monitored using a MAAP (Multi Angle Absorption Photometer) Thermo 5012 and a Dust Trak DRX-8533 TSI in the East Campus of University of São Paulo, close to important highways and also to the largest airport of Brazil (Guarulhos Airport). Average BC concentration was 1.7 μg/m3 with some peaks above 17.0 μg/m3 and for PM2.5 average was 10.2 μg/m3. Particle concentrations reached values greater than the air quality standard (60 μg/m3) in the winter months. Winds coming from the East direction predominate. Traffic restrictions to heavy duty vehicles in the road-rings next to the sampling site during some hours of the day are the responsible for the daily BC and PM2.5 behavior (figure below), where high concentrations occur early in the morning and late at night, when heavy diesel vehicles are released for transit. Seasonal variations are different for BC and PM2.5 due to local sources of BC and meteorological conditions that have more influence on the particles. The weekly variation indicates that concentrations are lower on Sundays and higher from Tuesday to Thursday. Emission factors for BC were calculated based on traffic information.

  7. Carbon black networking in elastomers monitored by simultaneous rheological and dielectric investigations

    Science.gov (United States)

    Steinhauser, Dagmar; Möwes, Markus; Klüppel, Manfred

    2016-12-01

    The rheo-dielectric response of carbon black filled elastomer melts is investigated by dielectric relaxation spectroscopy in the frequency range from 0.1 Hz up to 10 MHz during oszillatory shearing in a plate-plate rheometer. Various concentrations and types of carbon blacks dispersed in a non-crosslinked EPDM melt are considered. It is demonstrated that during heat treatment at low strain amplitude a pronounced flocculation of filler particles takes place leading to a successive increase of the shear modulus and conductivity. Followed up by a strain sweep, the filler network breaks up and both quantities decrease simultaneously with increasing strain amplitude. Two relaxation times, obtained from a Cole-Cole fit of the dielectric spectra, are identified, which both decrease strongly with increasing flocculation time. This behaviour is analyzed in the frame of fractal network models, describing the effect of structural disorder of the conducting carbon black network on the diffusive charge transport. Significant deviations from the predictions of percolation theory are observed, which are traced back to a superimposed cluster-cluster aggregation process (CCA). During flocculation, a universal scaling behaviour holds between the conductivity and the corresponding high frequency relaxation time, which fits all the measured data. The scaling exponent agrees fairly well with the prediction obtained from CCA. It is demonstrated that the underlying basic mechanism is a change of the correlation length of the filler network, i.e. the size of the fractal heterogeneities. This decreases during flocculation due to the formation of additional conductive paths, making the system more homogeneous. An addition less pronounced effect is found from nanoscopic gaps between adjacent filler particles, which decrease during flocculation. The same universal scaling behaviour, as obtained for flocculation, is found for temperature-dependent dielectric measurements of the cured

  8. Characterization of black carbon at roadside sites and along vehicle roadways in the Bangkok Metropolitan Region

    Science.gov (United States)

    Hung, Nguyen Tri Quang; Lee, Seung-Bok; Hang, Nguyen Thanh; Kongpran, Jira; Kim Oanh, Nguyen Thi; Shim, Shang-Gyoo; Bae, Gwi-Nam

    2014-08-01

    To understand the seasonality of concentrations of traffic-related black carbon (BC) in a megacity, BC concentrations in fine particles were monitored at the roadside and on roads during both the wet and dry seasons of 2010 in the city center of Bangkok, Thailand. The BC concentration measured every 2 min by an aethalometer at the Dingdaeng roadside in the dry season was 17.9 ± 6.6 μg m-3, which was 1.6-fold higher than the value (11.5 ± 2.7 μg m-3) during the wet season. This seasonal difference could not be explained by washout by rain but was instead due to more frequent upwind conditions caused by a prevailing wind direction from the monitoring site toward the road in the wet season. When the prevailing wind direction was from the road, the average BC concentration at the roadside increased up to 30 μg m-3 during both seasons. In contrast, when the wind direction was from the site to the road, the BC concentration was reduced to the level of urban background concentrations measured inside Lumphini Park and the Dusit Zoo of Bangkok. Roadside BC concentrations were strongly correlated with NOx concentrations and elemental carbon (EC) concentrations measured in 24-h PM2.5 filter samples. Both relationships exhibited linear determination coefficients of more than 0.80, implying that NOx can be used as an indicator and an alternative for traffic-related BC at this roadside site when real-time BC monitors are not available. The average on-road BC concentration (25.5 μg m-3) was similar to the average at the roadside under downwind conditions (25.5 μg m-3) from morning to evening only. In contrast, the latter value was 1.7-fold higher than the daily average at the roadside (14.7 μg m-3) and 7.3-fold higher than the urban background level during the daytime (3.5 μg m-3). The results of this study suggest that residents who live next to major roads, pedestrians at the roadside, and drivers on the roads experience a high risk of exposure to severe levels of

  9. Carbon dioxide concentration in Mediterranean greenhouses : how much lost production?

    NARCIS (Netherlands)

    Stanghellini, C.; Incrocci, L.; Gazquez, J.C.; Dimauro, B.

    2008-01-01

    In the absence of artificial supply of carbon dioxide in the greenhouse environment, the CO2 absorbed in the process of photosynthesis must ultimately come from the external ambient through the ventilation openings. This requires that the CO2 concentration within the house must be lower than the ext

  10. Migration of nanoparticles from plastic packaging materials containing carbon black into foodstuffs.

    Science.gov (United States)

    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.

  11. Estimate the influence of snow grain size and black carbon on albedo

    Institute of Scientific and Technical Information of China (English)

    ZhongMing Guo; NingLian Wang; XiaoBo Wu; HongBo Wu; YuWei Wu

    2015-01-01

    Estimation of the influence of snow grain size and black carbon on albedo is essential in obtaining the accurate albedo. In this paper, field measurement data, including snow grain size, snow depth and density was obtained. Black carbon samples were collected from the snow surface. A simultaneous observation using Analytical Spectral Devices was employed in the Qiyi Glacier located in the Qilian Mountain. Analytical Spectral Devices spectrum data were used to analyze spectral re-flectance of snow for different grain size and black carbon content. The measurements were compared with the results obtained from the Snow, Ice, and Aerosol Radiation model, and the simulation was found to correlate well with the ob-served data. However, the simulated albedo was near to 0.98 times of the measured albedo, so the other factors were as-sumed to be constant using the corrected Snow, Ice, and Aerosol Radiation model to estimate the influence of measured snow grain size and black carbon on albedo. Field measurements were controlled to fit the relationship between the snow grain size and black carbon in order to estimate the influence of these factors on the snow albedo.

  12. Effect of molecular weight on the electrophoretic deposition of carbon black nanoparticles in moderately viscous systems.

    Science.gov (United States)

    Modi, Satyam; Panwar, Artee; Mead, Joey L; Barry, Carol M F

    2013-08-06

    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.

  13. Estimation of Black Carbon Emissions from Dry Dipterocarp Forest Fires in Thailand

    Directory of Open Access Journals (Sweden)

    Ubonwan Chaiyo

    2014-12-01

    Full Text Available This study focused on the estimation of black carbon emissions from dry dipterocarp forest fires in Thailand. Field experiments were set up at the natural forest, Mae Nam Phachi wildlife sanctuary, Ratchaburi Province, Thailand. The dead leaves were the main component consumed of the surface biomass with coverage higher than 90% in volume and mass. The dead leaves load was 342 ± 190 g∙m−2 and followed by a little mass load of twig, 100 g∙m−2. The chemical analysis of the dead leaves showed that the carbon content in the experimental biomass fuel was 45.81 ± 0.04%. From the field experiments, it was found that 88.38 ± 2.02% of the carbon input was converted to carbon released to the atmosphere, while less than 10% were left in the form of residues, and returned to soil. The quantity of dead leaves consumed to produce each gram of carbon released was 2.40 ± 0.02 gdry biomass burned. From the study, the emissions factor of carbon dioxide, carbon monoxide, particulate matter (PM2.5 and black carbon amounted 1329, 90, 26.19 and 2.83 g∙kg−1dry biomass burned, respectively. In Thailand, the amount of black carbon emissions from dry dipterocarp forest fires amounted 17.43 tonnes∙y−1.

  14. Dissolved black carbon along the land to ocean continuum of Paraiba do Sul River, Brazil

    Science.gov (United States)

    Marques da Silva Junior, Jomar; Dittmar, Thorsten; Niggemann, Jutta; Gomes de Almeida, Marcelo; de Rezende, Carlos Eduardo

    2016-04-01

    Rivers annually carry 25-28 Tg of pyrogenic dissolved organic matter (or dissolved black carbon, DBC) into the ocean, which is equivalent to about 10% of the entire land-ocean flux of dissolved organic carbon (Jaffé et al., Science 340, 345-347). Objective of this study was to identify the main processes behind the release and turnover of DBC on a riverine catchment scale. As model system we chose the land to ocean continuum of Paraíba do Sul River (Brazil), the only river system for which long-term DBC flux data exist (Dittmar, Rezende et al., Nature Geoscience 5, 618-622). The catchment was originally covered by Atlantic rain forest (mainly C3 plants) which was almost completely destroyed over the past centuries by slash-and-burn. As a result, large amounts of wood-derived charcoal reside in the soils. Today, fire-managed pasture and sugar cane (both dominated by C4 plants) cover most of the catchment. Water samples were collected at 24 sites along the main channel of the river, at 14 sites of the main tributaries and at 21 sites along the salinity gradient in the estuary and up to 35 km offshore. Sampling was performed in the wet seasons of 2013 and 2014, and the dry season of 2013. DBC was determined on a molecular level as benzenepolycarboxylic acids after nitric acid oxidation (Dittmar, Limnology and Oceanography: Methods 6, 230-235). Stable carbon isotopes (δ13C) were determined in solid phase extractable dissolved organic carbon (SPE-DOC) to distinguish C4 and C3 sources. Our results clearly show a relationship between hydrology and DBC concentrations in the river, with highest DBC concentrations in the wet season and lowest in the dry season. This relationship indicates that DBC is mainly mobilized from the upper soil horizons during heavy rainfalls. A significant correlation between DBC concentrations and δ13C-SPE-DOC indicated that most of DBC in the river system originates from C3 plants, i.e. from the historic burning event of the Atlantic rain

  15. Personal black carbon exposure influences ambulatory blood pressure: air pollution and cardiometabolic disease (AIRCMD-China) study.

    Science.gov (United States)

    Zhao, Xiaoyi; Sun, Zhichao; Ruan, Yanping; Yan, Jianhua; Mukherjee, Bhramar; Yang, Fumo; Duan, Fengkui; Sun, Lixian; Liang, Ruijuan; Lian, Hui; Zhang, Shuyang; Fang, Quan; Gu, Dongfeng; Brook, Jeffrey R; Sun, Qinghua; Brook, Robert D; Rajagopalan, Sanjay; Fan, Zhongjie

    2014-04-01

    Few prospective studies have assessed the blood pressure effect of extremely high air pollution encountered in Asia's megacities. The objective of this study was to evaluate the association between combustion-related air pollution with ambulatory blood pressure and autonomic function. During February to July 2012, personal black carbon was determined for 5 consecutive days using microaethalometers in patients with metabolic syndrome in Beijing, China. Simultaneous ambient fine particulate matter concentration was obtained from the Beijing Municipal Environmental Monitoring Center and the US Embassy. Twenty-four-hour ambulatory blood pressure and heart rate variability were measured from day 4. Arterial stiffness and endothelial function were obtained at the end of day 5. For statistical analysis, we used generalized additive mixed models for repeated outcomes and generalized linear models for single/summary outcomes. Mean (SD) of personal black carbon and fine particulate matter during 24 hours was 4.66 (2.89) and 64.2 (36.9) μg/m(3). Exposure to high levels of black carbon in the preceding hours was associated significantly with adverse cardiovascular responses. A unit increase in personal black carbon during the previous 10 hours was associated with an increase in systolic blood pressure of 0.53 mm Hg and diastolic blood pressure of 0.37 mm Hg (95% confidence interval, 0.17-0.89 and 0.10-0.65 mm Hg, respectively), a percentage change in low frequency to high frequency ratio of 5.11 and mean interbeat interval of -0.06 (95% confidence interval, 0.62-9.60 and -0.11 to -0.01, respectively). These findings highlight the public health effect of air pollution and the importance of reducing air pollution.

  16. Black carbon in the Arctic: the underestimated role of gas flaring and residential combustion emissions

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2013-09-01

    Full Text Available Arctic haze is a seasonal phenomenon with high concentrations of accumulation-mode aerosols occurring in the Arctic in winter and early spring. Chemistry transport models and climate chemistry models struggle to reproduce this phenomenon, and this has recently prompted changes in aerosol removal schemes to remedy the modeling problems. In this paper, we show that shortcomings in current emission data sets are at least as important. We perform a 3 yr model simulation of black carbon (BC with the Lagrangian particle dispersion model FLEXPART. The model is driven with a new emission data set ("ECLIPSE emissions" which includes emissions from gas flaring. While gas flaring is estimated to contribute less than 3% of global BC emissions in this data set, flaring dominates the estimated BC emissions in the Arctic (north of 66° N. Putting these emissions into our model, we find that flaring contributes 42% to the annual mean BC surface concentrations in the Arctic. In March, flaring even accounts for 52% of all Arctic BC near the surface. Most of the flaring BC remains close to the surface in the Arctic, so that the flaring contribution to BC in the middle and upper troposphere is small. Another important factor determining simulated BC concentrations is the seasonal variation of BC emissions from residential combustion (often also called domestic combustion, which is used synonymously in this paper. We have calculated daily residential combustion emissions using the heating degree day (HDD concept based on ambient air temperature and compare results from model simulations using emissions with daily, monthly and annual time resolution. In January, the Arctic-mean surface concentrations of BC due to residential combustion emissions are 150% higher when using daily emissions than when using annually constant emissions. While there are concentration reductions in summer, they are smaller than the winter increases, leading to a systematic increase of

  17. Black carbon in the Arctic: the underestimated role of gas flaring and residential combustion emissions

    Science.gov (United States)

    Stohl, A.; Klimont, Z.; Eckhardt, S.; Kupiainen, K.; Shevchenko, V. P.; Kopeikin, V. M.; Novigatsky, A. N.

    2013-09-01

    Arctic haze is a seasonal phenomenon with high concentrations of accumulation-mode aerosols occurring in the Arctic in winter and early spring. Chemistry transport models and climate chemistry models struggle to reproduce this phenomenon, and this has recently prompted changes in aerosol removal schemes to remedy the modeling problems. In this paper, we show that shortcomings in current emission data sets are at least as important. We perform a 3 yr model simulation of black carbon (BC) with the Lagrangian particle dispersion model FLEXPART. The model is driven with a new emission data set ("ECLIPSE emissions") which includes emissions from gas flaring. While gas flaring is estimated to contribute less than 3% of global BC emissions in this data set, flaring dominates the estimated BC emissions in the Arctic (north of 66° N). Putting these emissions into our model, we find that flaring contributes 42% to the annual mean BC surface concentrations in the Arctic. In March, flaring even accounts for 52% of all Arctic BC near the surface. Most of the flaring BC remains close to the surface in the Arctic, so that the flaring contribution to BC in the middle and upper troposphere is small. Another important factor determining simulated BC concentrations is the seasonal variation of BC emissions from residential combustion (often also called domestic combustion, which is used synonymously in this paper). We have calculated daily residential combustion emissions using the heating degree day (HDD) concept based on ambient air temperature and compare results from model simulations using emissions with daily, monthly and annual time resolution. In January, the Arctic-mean surface concentrations of BC due to residential combustion emissions are 150% higher when using daily emissions than when using annually constant emissions. While there are concentration reductions in summer, they are smaller than the winter increases, leading to a systematic increase of annual mean Arctic

  18. Effect of carbon-black treatment by radiation emulsion polymerization on temperature dependence of resistivity of carbon-black-filled polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Jia Shaojin [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China) and Department of Chemical Engineering, Shanghai University, Chengzhong Road 20, Shanghai 201800 (China)]. E-mail: jiashaojin2@yahoo.com.cn; Jiang Pingkai [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Zhang Zhicheng [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang Zhongguang [Key Lab of Insulation and Thermal of Aging of Shanghai, Department of Polymer Engineering and Science, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China)

    2006-04-15

    High dispersibility and stability of carbon black particles in low-density-polyethylene (LDPE) matrix were obtained by radiation emulsion polymerization on carbon particles surface, and electrical resistivities of its simple were examined. First carbon particles treatment on radiation emulsion polymerization on surface were synthesized by the reaction with a polymer-emulsion systems containing reactive group in the molecular unit, carbon particles and emulsifier. Then, the carbon particles treatment on radiation emulsion polymerization on surface was dispersed into LDPE, and its composites were prepared for electrical measurements. The effect of radiation crosslinking of the composite on the Positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomenon was investigated. The experimental results showed that PTC and NTC effects of the composites were obviously influenced by the irradiation dose. Various microstructure-exploring means were used to study the conductive composite, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM)

  19. Effect of carbon-black treatment by radiation emulsion polymerization on temperature dependence of resistivity of carbon-black-filled polymer blends

    Science.gov (United States)

    Shaojin, Jia; Pingkai, Jiang; Zhicheng, Zhang; Zhongguang, Wang

    2006-04-01

    High dispersibility and stability of carbon black particles in low-density-polyethylene (LDPE) matrix were obtained by radiation emulsion polymerization on carbon particles surface, and electrical resistivities of its simple were examined. First carbon particles treatment on radiation emulsion polymerization on surface were synthesized by the reaction with a polymer-emulsion systems containing reactive group in the molecular unit, carbon particles and emulsifier. Then, the carbon particles treatment on radiation emulsion polymerization on surface was dispersed into LDPE, and its composites were prepared for electrical measurements. The effect of radiation crosslinking of the composite on the Positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomenon was investigated. The experimental results showed that PTC and NTC effects of the composites were obviously influenced by the irradiation dose. Various microstructure-exploring means were used to study the conductive composite, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM).

  20. Black carbon in deep-sea sediments from the northeastern equatorial Pacific Ocean

    Science.gov (United States)

    Kim, D.; Lee, Y.; Hyeong, K.; Yoo, C.

    2011-12-01

    Deep-sea sediment core is a good archive for understanding the land-ocean interactions via atmosphere, due to it is little influenced by fluvial and continental shelf processes. This study dealt with black carbon(BC) in a 328 cm-long piston core collected from the northeastern equatorial Pacific Ocean (16°12'N, 125°59'W), covering the last 15 Ma (Hyeong at al., 2004). BC is a common name of carbon continuum formed by incomplete combustion of fossil fuels and plant materials. Though it may react with ozone and produce water-soluble organic carbon, BC has commonly refractory nature. Thus BC in preindustrial sediment can be a tracer of forest-fire events. BC is purely terrestrial in origin, and is transported to marine environments by atmospheric and fluvial processes. Therefore, distribution of BC in deep-sea sediments could be used to understand atmospheric circulation. Chemical oxidation was used to determine BC in this study following Lim and Cachier (1996). Concentration of BC varies from 0.010% to 0.233% of total sediments. Mass accumulation rate (MAR) of BC ranged between 0.077 mg/cm^2/1000 yrs and 47.49 mg/cm^21000 yrs. It is noted that MAR in sediments younger than 8 Ma (av. 9.0 mg/cm^2/1000 yrs) is higher than that in sediments older than 8 Ma (av. 3.2 mg/cm^2/1000 yrs). Stable carbon isotope value of BC increases with time from the low δ13C value near 13 Ma until it reaches the highest value near 4 Ma. Change of MAR seems to be related to the meridional migration of Intertropical Convergence Zone (ITCZ) at around 8 Ma in the study area (cf., Hyeong at al., 2004). Accordingly, higher BC content in sediment younger than 8 Ma seems to be accounted for by its derivation from the Northern Hemisphere compared to that from the Southern Hemisphere in older sediment. Increase of carbon isotope value with time seems to be related to expansion of C4 grassland. C4 grassland expansion might have been caused by change of atmosphreic cycle, which moved dry subtropical

  1. GHG and black carbon emission inventories from Mezquital Valley: The main energy provider for Mexico Megacity.

    Science.gov (United States)

    Montelongo-Reyes, M M; Otazo-Sánchez, E M; Romo-Gómez, C; Gordillo-Martínez, A J; Galindo-Castillo, E

    2015-09-15

    The greenhouse gases and black carbon emission inventory from IPCC key category Energy was accomplished for the Mezquital Valley, one of the most polluted regions in Mexico, as the Mexico City wastewater have been continuously used in agricultural irrigation for more than a hundred years. In addition, thermoelectric, refinery, cement and chemistry industries are concentrated in the southern part of the valley, near Mexico City. Several studies have reported air, soil, and water pollution data and its main sources for the region. Paradoxically, these sources contaminate the valley, but boosted its economic development. Nevertheless, no research has been done concerning GHG emissions, or climate change assessment. This paper reports inventories performed by the 1996 IPCC methodology for the baseline year 2005. Fuel consumption data were derived from priority sectors such as electricity generation, refineries, manufacturing & cement industries, transportation, and residential use. The total CO2 emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO2 sources were energy transformation (69%) and manufacturing (19%). Total black carbon emissions were estimated by a bottom-up method at 0.66 Gg. The principal contributor was on-road transportation (37%), followed by firewood residential consumption (26%) and cocked brick manufactures (22%). Non-CO2 gas emissions were also significant, particularly SO2 (255.9 Gg), which accounts for 80% of the whole Hidalgo State emissions. Results demonstrated the negative environmental impact on Mezquital Valley, caused by its role as a Megacity secondary fuel and electricity provider, as well as by the presence of several cement industries.

  2. Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau

    Science.gov (United States)

    Kopacz, M.; Mauzerall, D. L.; Wang, J.; Leibensperger, E. M.; Henze, D. K.; Singh, K.

    2011-03-01

    The remote and high elevation regions of central Asia are influenced by black carbon (BC) emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and find the forcing due to the BC induced snow-albedo effect to vary from 5-15 W m-2 within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo likely accelerates glacier melting. Our analysis may help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.

  3. Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    M. Kopacz

    2011-03-01

    Full Text Available The remote and high elevation regions of central Asia are influenced by black carbon (BC emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and find the forcing due to the BC induced snow-albedo effect to vary from 5–15 W m−2 within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo likely accelerates glacier melting. Our analysis may help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.

  4. Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    M. Kopacz

    2010-09-01

    Full Text Available The remote and high elevation regions of central Asia are influenced by black carbon (BC emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and estimate the forcing due to the BC induced snow-albedo effect at about 5–15 W m−2 within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo accelerates glacier melting. Our analysis can help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.

  5. Abundance and sinking of particulate black carbon in the western Arctic and Subarctic Oceans

    Science.gov (United States)

    Fang, Ziming; Yang, Weifeng; Chen, Min; Zheng, Minfang; Hu, Wangjiang

    2016-07-01

    The abundance and sinking of particulate black carbon (PBC) were examined for the first time in the western Arctic and Subarctic Oceans. In the central Arctic Ocean, high PBC concentrations with a mean of 0.021 ± 0.016 μmol L‑1 were observed in the marginal ice zone (MIZ). A number of parameters, including temperature, salinity and 234Th/238U ratios, indicated that both the rapid release of atmospherically deposited PBC on sea ice and a slow sinking rate were responsible for the comparable PBC concentrations between the MIZ and mid-latitudinal Pacific Ocean (ML). On the Chukchi and Bering Shelves (CBS), PBC concentrations were also comparable to those obtained in the ML. Further, significant deficits of 234Th revealed the rapid sinking of PBC on the CBS. These results implied additional source terms for PBC in addition to atmospheric deposition and fluvial discharge on the western Arctic shelves. Based on 234Th/238U disequilibria, the net sinking rate of PBC out of the surface water was ‑0.8 ± 2.5 μmol m‑3 d‑1 (mean ± s.d.) in the MIZ. In contrast, on the shelves, the average sinking rate of PBC was 6.1 ± 4.6 μmol m‑3 d‑1. Thus, the western Arctic Shelf was probably an effective location for burying PBC.

  6. A global 3-D CTM evaluation of black carbon in the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    C. He

    2014-03-01

    Full Text Available We evaluate the black carbon (BC simulations for 2006 over the Tibetan Plateau by a global 3-D chemical transport model using surface observations of BC in surface air and in snow and BC absorption aerosol optical depth (AAOD. Using updated Asian anthropogenic BC emissions (Lu et al., 2011; Zhang et al., 2009 and global biomass burning emissions (Randerson et al., 2012; van der Werf et al., 2010, model results of both surface BC and BC in snow are statistically in good agreement with observations (biases < 15%. Model results capture the seasonal variation of surface BC concentration, but the observed wintertime high values at rural sites in the Indo-Gangetic Plain are absent in the model. Model results are in general agreement with observations (within a factor of two at remote sites. Model simulated BC concentrations in snow are spatiotemporally consistent with observations at most sites. We find that modeled BC AAOD are significantly lower than observations to the northwest of the Plateau and along the southern slopes of the Himalayas during winter and spring, reflecting model deficiencies in emissions, topography and BC mixing state. We find that anthropogenic emissions strongly affect surface BC concentration and AAOD, while the BC aging mainly affects BC in snow over the Plateau.

  7. Aerosol black carbon characteristics over a high-altitude Western Ghats location in Southern India

    Science.gov (United States)

    Udayasoorian, C.; Jayabalakrishnan, R. M.; Suguna, A. R.; Gogoi, Mukunda M.; Babu, S. Suresh

    2014-10-01

    Aerosol black carbon (BC) mass concentrations were continuously monitored over a period of 2 years (April 2010 to May 2012) from a high-altitude location Ooty in the Nilgiris Mountain range in southern India to characterize the distinct nature of absorbing aerosols and their seasonality. Despite being remote and sparsely inhabited, BC concentrations showed significant seasonality with higher values (~ 0.96 ± 0.35 μg m-3) in summer (March to May), attributed to increased vertical transport of effluents in the upwind valley regions, which might have been confined to the surrounding valley regions within the very shallow winter boundary layer. The local atmospheric boundary layer (ABL) influence in summer was further modulated by the long-range transported aerosols from the eastern locations of Ooty. During monsoon (June-August), the concentrations were far reduced (~ 0.23 ± 0.06 μg m-3) due to intense precipitation. Diurnal variations were found conspicuous mainly during summer season associated with local ABL. The spectral absorption coefficients (αabs) depicted, in general, flatter distribution (mostly < 1.0 for more than 85% of daily mean values), suggesting the relative dominance of fossil fuel combustion, though showed marginal seasonal change with higher values of αabs in summer.

  8. Inventory and burial fluxes of Black Carbon in the Swedish continental shelf sediments

    Science.gov (United States)

    Sánchez-García, L.; Cato, I.; Gustafsson, Ö.

    2009-04-01

    Highly condensed black carbon (BC) particles, mainly derived from incomplete combustion of biomass and fossil fuel, are involved in several important processes in the biogeosphere [1], including sedimentary carbon burial, sequestration of organic pollutants in soils and sediments, affecting Earth's radiative heat balance and even human respiratory health. BC is commonly found to constitute several to 20% of total sedimentary carbon, and thus plays an important but poorly constrained role in the global biogeospheric carbon cycle. Sequestration of biogenic carbon as BC is a direct sink of the element from the rapidly cycling atmosphere-biosphere reservoirs, whereas burial of petrogenic/fossil BC is simply a conversion of one form of geological carbon to another [2]. Considerable emphasis has been made on the relevant role this recalcitrant form of organic matter (OM) may play on the global C cycle and yet large uncertainty exists around BC detection and quantification. This work seeks to provide a large-scale estimate of the reservoir and burial sink flux of BC in sediments from the extensive Swedish continental shelf (SCS), as a first approach to global inventories. To this end, a total of 120 sediment samples were collected from the Exclusive Economic Zone (EEZ) along the ?2000 km SCS stretch. The most recalcitrant fraction of the sedimentary OM was isolated and determined by means of a commonly applied method in biogeochemical studies of soils and sediments: chemo-thermal oxidation at 375˚ C in air (CTO-375). The obtained BC concentration was used to estimate the inventory and burial flux of BC in the SCS surface sediments, following [3], which takes into account key geophysical and geochemical properties of the nine distinct sedimentary regimes of the SCS that was separately assessed. Globally representative values of the sediment properties (e.g. density of dried sediments, bioturbated mixing depth, sedimentation rate or porosity over the mixed depth) were

  9. Adsorption removal of acid black 1 from aqueous solution using ordered mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Xiaoming, E-mail: pengxiaoming70@126.com [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Hu, Xijun [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China); Fu, Dafang, E-mail: fdf@seu.edu.cn [School of Civil Engineering, Southeast University, Nanjing 210096 (China); Lam, Frank L.Y. [Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong,China (China)

    2014-03-01

    Highlights: • Ordered mesoporous carbon was prepared using template. • Ordered mesoporous carbon was introduced of N-containing group by Chemical vapor deposition method. • Modified CMK-3 have better adsorption capacity and efficiency than virgin CMK-3 to removal AB1 dye. - Abstract: A novel ordered mesoporous carbon CMK-3 and synthetic CMK-3 containing nitrogen functional groups by ammonia-treated were applied for acid black 1(AB1) dye adsorption. The ammonia-treated(chemical vapor deposition method) before and after CMK-3 were characterized by using a Micrometitics ASAP 2020 surface area analyzer (ASAP 2020), Fourier transform infrared spectrophotometer (FT–IR), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM) and equilibrium studies. This result indicates that the prepared CMK-3 and modified CMK-3 were almost uniform, as rope-like domains and their uniform mesopore with diameter centered at 3.2 nm and 3.7 nm. The FIIR analysis depicted that the presence of a variety of new basic functional groups on the modified CMK-3 surface. Several effect variables of pH, dye concentration and temperature were studied. The pseudo second-order model showed the fitter well to agree with the kinetic data. The experimental data were analyzed by the Langmuir and Freundlich models, with the latter found to closely the isotherm model. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The results show that CMK-3 using ammonia gas modified by thermal treatment system is an effective method to improvement capacity as it shows the highest adsorption capacity of AB1, as compared to the unmodified CMK-3 and the bamboo-based carbon, respectively.

  10. Black carbon and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of China's marginal seas

    Institute of Scientific and Technical Information of China (English)

    KANG Yanju; WANG Xuchen; DAI Minhan; FENG Huan; LI Anchun; SONG Qian

    2009-01-01

    This study investigates the distribution of black carbon (BC) and its correlation with total polycyclic aromatic hydrocarbons (ΣPAH) in the surface sediments of China's marginal seas. BC content ranges from <0.10 to 2.45 mg/g dw (grams dry weight) in the sediments studied, and varied among the different coastal regions. The Bohai Bay sediments had the highest BC contents (average 2.18 mg/g dw),which comprises a significant fraction (27%-41%) of the total organic carbon (TOC) preserved in the sediments. In comparison, BC in the surface sediments of the North Yellow Sea, Jiaozhou Bay, East China Sea and the South China Sea is less abundant and accounted for an average of 6%, 8%, 14% and 5%,respectively, of the sedimentary organic carbon pool. The concentration of ΣPAH in the surface sediments ranges from 41 to 3 667 ng/g dw and showed large spatial variations among the sampling sites of different costal regions. The Bohai Bay has the highest ΣPAH values, ranging from 79 to 3 667 ng/g dw. This reflects the high anthropogenically contaminated nature of the sediments in the bay. BC is positively correlated to TOC but a strong correlation is not found between BC and ΣPAH in the surface sediments studied, suggesting that BC and PAHs preserved in the sediments are derived from different sources and controlled by different biogeochemical processes. Our study suggests that the abundance of BC preserved in the sediments could represent a significant sink pool of carbon cycling in China's marginal seas.

  11. Thickness effect on electric resistivity on polystyrene and carbon black- based composites

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Lopez, S; Vigueras-Santiago, E [Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA) Facultad de Quimica, Paseo Colon Esquina con Paseo Tollocan, s/n, CP 50000, Toluca (Mexico); Mayorga-Rojas, M; Reyes-Contreras, D, E-mail: eviguerass@uaemex.m [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico. Av. Instituto Literario 100 Ote. C. P. 50000, Toluca (Mexico)

    2009-05-01

    Changes on electrical resistivity were experimentally studied for polystyrene and carbon black-based composites respect to the temperature. 22% w/w carbon black composite films at 30{mu}m, 2mm y 1cm thick were submitted to thermal heating-cooling cycles from room temperature to 100 deg. C, slightly up to T{sub g} of the composite. For each cycle changes on electrical resistivity constituent a hysteresis loop that depends on the sample thickness. The changes during the heating stage could be explained as a consequence of the thermal expansion and mobility of the polymer chains at T{sub g}, producing a disconnecting of the electrical contacts among carbon black particles and an important increasing (200%) of the electrical resistivity. For each cycle, the hysteresis loop was observed in thicker samples, whereas for 30 mu m thickness sample the hysteresis loop was lost after four cycles.

  12. Influence of γ-ray Irradiation on the PTC Effect of EPDM/Carbon Black Composite

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ Introduction The positive temperature coefficient(PTC) effect is characterized by an increase of resistivity with an elevated temperature.The PTC effect of carbon black(CB) filled polymers is useful for self-regulation heaters,over-current protectors,sensors,etc.Much work has been done on the PTC effect of the carbon black filled crystalline polymer composite[1-4],whereas carbon black filled amorphous polymers have not drawn researchers much attention because the PTC effect in these composites is small or cannot be detected[5-7].In this work,the influence of γ-ray irradiation on the PTC effect of CB filled amorphous ethylene-propylene-diene terpolymer(EPDM) composites was studied.

  13. The effects of additional black carbon on Arctic sea ice surface albedo: variation with sea ice type and snow cover

    Directory of Open Access Journals (Sweden)

    A. A. Marks

    2013-03-01

    Full Text Available Black carbon in sea ice will decrease sea ice surface albedo through increased absorption of incident solar radiation, exacerbating sea ice melting. Previous literature has reported different albedo responses to additions of black carbon in sea ice and has not considered how a snow cover may mitigate the effect of black carbon in sea ice. Sea ice is predominately snow covered. Visible light absorption and light scattering coefficients are calculated for a typical first year and multi-year sea ice and "dry" and "wet" snow types that suggest black carbon is the dominating absorbing impurity. The albedo response of first year and multi-year sea ice to increasing black carbon, from 1–1024 ng g−1, in a top 5 cm layer of a 155 cm thick sea ice was calculated using the radiative transfer model: TUV-snow. Sea ice albedo is surprisingly unresponsive to black carbon additions up to 100 ng g−1 with a decrease in albedo to 98.7% of the original albedo value due to an addition of 8 ng g−1 of black carbon in first year sea ice compared to an albedo decrease to 99.6% for the same black carbon mass ratio increase in multi-year sea ice. The first year sea ice proved more responsive to black carbon additions than the multi-year ice. Comparison with previous modelling of black carbon in sea ice suggests a more scattering sea ice environment will be less responsive to black carbon additions. Snow layers on sea ice may mitigate the effects of black carbon in sea ice. "Wet" and "dry" snow layers of 0.5, 1, 2, 5 and 10 cm were added onto the sea ice surface and the snow surface albedo calculated with the same increase in black carbon in the underlying sea ice. Just a 0.5 cm layer of snow greatly diminishes the effect of black carbon on surface albedo, and a 2–5 cm layer (less than half the e-folding depth of snow is enough to "mask" any change in surface albedo owing to additional black carbon in sea ice, but not thick enough to ignore the underlying sea ice.

  14. Seasonality of global and Arctic black carbon processes in the Arctic Monitoring and Assessment Programme models: Global and Arctic Black Carbon Processes

    Energy Technology Data Exchange (ETDEWEB)

    Mahmood, Rashed [School of Earth and Ocean Sciences, University of Victoria, Victoria British Columbia Canada; Department of Meteorology, COMSATS Institute of Information Technology, Islamabad Pakistan; von Salzen, Knut [School of Earth and Ocean Sciences, University of Victoria, Victoria British Columbia Canada; Canadian Center for Climate Modelling and Analysis, Environment and Climate Change Canada, University of Victoria, Victoria British Columbia Canada; Flanner, Mark [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor Michigan USA; Sand, Maria [Center for International Climate and Environmental Research-Oslo, Oslo Norway; Langner, Joakim [Swedish Meteorological and Hydrological Institute, Norrköping Sweden; Wang, Hailong [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Huang, Lin [Climate Chemistry Measurements and Research, Environment and Climate Change Canada, Toronto Ontario Canada

    2016-06-22

    This study quantifies black carbon (BC) processes in three global climate models and one chemistry transport model, with focus on the seasonality of BC transport, emissions, wet and dry deposition in the Arctic. In the models, transport of BC to the Arctic from lower latitudes is the major BC source for this region while Arctic emissions are very small. All models simulated a similar annual cycle of BC transport from lower latitudes to the Arctic, with maximum transport occurring in July. Substantial differences were found in simulated BC burdens and vertical distributions, with CanAM (NorESM) producing the strongest (weakest) seasonal cycle. CanAM also has the shortest annual mean residence time for BC in the Arctic followed by SMHI-MATCH, CESM and NorESM. The relative contribution of wet and dry deposition rates in removing BC varies seasonally and is one of the major factors causing seasonal variations in BC burdens in the Arctic. Overall, considerable differences in wet deposition efficiencies in the models exist and are a leading cause of differences in simulated BC burdens. Results from model sensitivity experiments indicate that scavenging of BC in convective clouds acts to substantially increase the overall efficiency of BC wet deposition in the Arctic, which leads to low BC burdens and a more pronounced seasonal cycle compared to simulations without convective BC scavenging. In contrast, the simulated seasonality of BC concentrations in the upper troposphere is only weakly influenced by wet deposition in stratiform (layer) clouds whereas lower tropospheric concentrations are highly sensitive.

  15. Scavenging of biomass burning refractory black carbon and ice nuclei in a Western Pacific extratropical storm

    Directory of Open Access Journals (Sweden)

    J. L. Stith

    2011-01-01

    Full Text Available In situ airborne sampling of refractory black carbon (rBC particles and Ice Nuclei (IN was conducted in and near an extratropical cyclonic storm in the Western Pacific Ocean during the Pacific Dust Experiment, PACDEX, in the spring of 2007. Airmass origins were from Eastern Asia. Cloud hydrometeors were evaporated by a counterflow virtual impactor and the residue was sampled by a single particle soot photometer (SP2 instrument and a continuous flow diffusion chamber ice nucleus detector. Clouds associated primarily with the warm sector of the storm were sampled at various locations and altitudes. In storm midlevels at temperatures where heterogeneous freezing is expected to be significant (here −24 to −29 °C, IN measurements from ice particle residues generally agreed well with simultaneous measurements of total ice concentrations provided that the measurements were made at ambient temperatures similar to those in the CFDC chamber, suggesting heterogeneous freezing as the dominant ice formation process in the mid levels of these warm sector clouds. Lower in the storm, at warmer temperatures (−22 to −6.4 °C, ice particle concentrations were similar to IN concentrations at CFDC chamber temperatures representative of colder temperatures. This is consistent with ice particles forming at storm mid-levels by heterogeneous freezing on IN, followed by sedimentation to lower altitudes. Homogeneous freezing did not appear to contribute significantly to midlevel ice concentrations and rime-splintering was also unlikely due to the absence of significant supercooled liquid water in the warm sector clouds. IN number concentrations were typically about a~factor of five to ten lower than simultaneous measurements of rBC concentrations in cloud.

  16. Concentration Levels of Imidacloprid and Dinotefuran in Five Tissue Types of Black Walnut, Juglans nigra

    Directory of Open Access Journals (Sweden)

    Paul Merten

    2013-11-01

    Full Text Available Black walnut, a valuable economic and environmentally important species, is threatened by thousand cankers disease. Systemic imidacloprid and dinotefuran applications were made to mature black walnut trees to evaluate their translocation and concentration levels in various tissue types including leaf, twig, trunk core, nutmeat, and walnut husk. The metabolism of imidacloprid in plants produces a metabolite, olefin-imidacloprid, which has been documented to have insecticidal properties in other systems. Trunk CoreTect (imidacloprid soil pellets and a trunk spray of dinotefuran were applied to mature black walnuts in spring 2011. Imidacloprid concentrations were detected in both the lower and upper strata in all tissue types tested and progressively increased through month 12 post-treatment in twig and leaf tissue. Olefin-imidacloprid was detected in the nutmeat and walnut husk. Dinotefuran was only detected in the first sampling period and was found in low concentration levels in leaf and twig tissue types, and was not detected in the trunk, nutmeat or the walnut husk.

  17. Black carbon measurements during winter 2013-2014 in Athens and intercomparison between different techniques

    Science.gov (United States)

    Liakakou, Eleni; Stravroulas, Jason; Roukounakis, Nikolaos; Paraskevopoulou, Despina; Fourtziou, Luciana; Psiloglou, Vassilis; Gerasopoulos, Evangelos; Sciare, Jean; Mihalopoulos, Nikolaos

    2014-05-01

    Black carbon (BC) is a particulate pollutant species emitted from the combustion of fuels, biomass burning for agricultural purposes and forest fires, with the first two anthropogenic sources being the major contributors to the atmospheric burden of BC. The presence of BC is important due to its direct and indirect physicochemical effects and its use as a tracer of burning and subsequent transport processes. Black carbon measurements took place during winter 2013 -2014 in the frame of a pollution monitoring experiment conducted at the urban site of Thissio, Athens (city center) at the premises of the National Observatory of Athens. The economic crisis in Greece and the resulting turn of Athens inhabitants to wood burning for domestic heating, has led to increased daily concentrations of BC in the range of 2-6 μg m-3, peaking at night time (15-20 μg m-3). Three different optical methods were used for the determination of BC. A Particle Soot Absorption Photometer (PSAP; Radiance Research) commercial instrument was used to monitor the light absorption coefficient (σap) at 565 nm of ambient aerosols, with 1 minute resolution. During parts of the campaign, a portable Aethalometer (AE-42; Magee Scientific) was also used to provide measurement of the aerosol BC content at 7 wavelengths over 5 minutes intervals. Exploiting the measurements at different wavelengths is was feasible to separate wood burning BC from BC related to fossil fuel. Two Multi Angle Absorption Photometers (MAAP; Thermo) were also operated as reference. Finally, aerosol samples were collected on 12-hour basis using a sequential dichotomous sampler for the sampling of PM2.5, PM2.5-10and PM10 fractions of aerosols on quartz filters, and the filters were analyzed for elemental carbon (EC) by a thermal - optical transmission technique. The main objective of the study is the intercomparison of the different BC monitoring techniques under a large range of ambient concentrations achieved due to the special

  18. Offsetting features of climate responses to anthropogenic sulfate and black carbon direct radiative forcings

    Science.gov (United States)

    Ocko, I.; Ramaswamy, V.

    2012-12-01

    The two most prominent anthropogenic aerosols—sulfate and black carbon—affect Earth's radiation budget in opposing ways. Here we examine how these aerosols independently impact the climate, by simulating climate responses from pre-industrial times (1860) to present-day (2000) for isolated sulfate and black carbon direct radiative forcings. The NOAA Geophysical Fluid Dynamics Laboratory CM2.1 global climate model is employed with prescribed distributions of externally mixed aerosols. We find that sulfate and black carbon induce opposite effects for a myriad of climate variables. Sulfate (black carbon) is generally cooling (warming), shifts the ITCZ southward (northward), reduces (enhances) the SH Hadley Cell, enhances (reduces) the NH Hadley Cell, and increases (decreases) total sea ice volume. Individually, sulfate and black carbon affect Hadley Cell circulation more than long-lived greenhouse gases, but the net aerosol effect is a weakened response due to opposite behaviors somewhat canceling out the individual effects. Because anthropogenic aerosols are a critical contributor to Earth's climate conditions, this study has implications for future climate changes as well.

  19. Morphology and mixing of black carbon particles collected in central California during the CARES field study

    Science.gov (United States)

    Moffet, Ryan C.; O'Brien, Rachel E.; Alpert, Peter A.; Kelly, Stephen T.; Pham, Don Q.; Gilles, Mary K.; Knopf, Daniel A.; Laskin, Alexander

    2016-11-01

    Aerosol absorption is strongly dependent on the internal heterogeneity (mixing state) and morphology of individual particles containing black carbon (BC) and other non-absorbing species. Here, we examine an extensive microscopic data set collected in the California Central Valley during the CARES 2010 field campaign. During a period of high photochemical activity and pollution buildup, the particle mixing state and morphology were characterized using scanning transmission X-ray microscopy (STXM) at the carbon K-edge. Observations of compacted BC core morphologies and thick organic coatings at both urban and rural sites provide evidence of the aged nature of particles, highlighting the importance of highly aged particles at urban sites during periods of high photochemical activity. Based on the observation of thick coatings and more convex BC inclusion morphology, either the aging was rapid or the contribution of fresh BC emissions at the urban site was relatively small compared to background concentrations. Most particles were observed to have the BC inclusion close to the center of the host. However, host particles containing inorganic rich inclusions had the BC inclusion closer to the edge of the particle. These measurements of BC morphology and mixing state provide important constraints for the morphological effects on BC optical properties expected in aged urban plumes.

  20. Black carbon fractal morphology and short-wave radiative impact: a modelling study

    Directory of Open Access Journals (Sweden)

    M. Kahnert

    2011-11-01

    Full Text Available We investigate the impact of the morphological properties of freshly emitted black carbon aerosols on optical properties and on radiative forcing. To this end, we model the optical properties of fractal black carbon aggregates by use of numerically exact solutions to Maxwell's equations within a spectral range from the UVC to the mid-IR. The results are coupled to radiative transfer computations, in which we consider six realistic case studies representing different atmospheric pollution conditions and surface albedos. The spectrally integrated radiative impacts of black carbon are compared for two different fractal morphologies, which brace the range of recently reported experimental observations of black carbon fractal structures. We also gauge our results by performing corresponding calculations based on the homogeneous sphere approximation, which is commonly employed in climate models. We find that at top of atmosphere the aggregate models yield radiative impacts that can be as much as 2 times higher than those based on the homogeneous sphere approximation. An aggregate model with a low fractal dimension can predict a radiative impact that is higher than that obtained with a high fractal dimension by a factor ranging between 1.1–1.6. Although the lower end of this scale seems like a rather small effect, a closer analysis reveals that the single scattering optical properties of more compact and more lacy aggregates differ considerably. In radiative flux computations there can be a partial cancellation due to the opposing effects of different error sources. However, this cancellation effect can strongly depend on atmospheric conditions and is therefore quite unpredictable. We conclude that the fractal morphology of black carbon aerosols and their fractal parameters can have a profound impact on their radiative forcing effect, and that the use of the homogeneous sphere model introduces unacceptably high biases in radiative impact studies. We

  1. Aerosol Absorption by Black Carbon and Dust: Implications of Climate Change and Air Quality in Asia

    Science.gov (United States)

    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.

  2. Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring

    Science.gov (United States)

    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.

  3. Comparison between measurements of black carbon, charcoal and associated nutrients in western Amazonan soils

    Science.gov (United States)

    Zimmerman, A. R.; McMichael, C.; Hanlon, C.; Bush, M. B.

    2011-12-01

    To construct fire and climate history and human occupation records from soils and lake sediment profiles, climatologists and anthropologists have traditionally measured charcoal abundances by microscopic image analysis. In contrast, geochemists have developed methods of black carbon (BC) quantification using chemical extraction. We compared charcoal (>0.5 mm particle size) versus BC (measured via the CTO-340 method of Kuhlbusch, 1995) in multiple soil profiles from four western Amazon regions with evidence of pre-Columbian occupation. A secondary goal of this project was to understand the relative influence of climate and humans in the fire and ecological history of the Amazon. BC concentration in soils of the Amazon varied widely from an average of 0.5 mg g 1 in cores around Lake Gentry (southeastern Peru) to 5.5 mg g 1 around Lake Ayauchi (southeastern Ecuador), corresponding to the evidence of greater land use around the latter. Surprising, BC concentrations in habitation horizon soils at Quistococha, near Iquitos, Peru were similar to Lake Gentry, averaging about 0.6 mg g 1. However, BC as a percent of soil organic carbon (SOC) was much more uniform with an average of 12.0, 13.3, 14.6, and 13.0% in Quistococha, Gentry, Ayauchi, and Los Amigos (central-eastern Peru) soils, respectively, suggesting that the same processes that concentrate SOC also concentrate BC. BC may act to protect SOC via sorption or produce SOC via microbial community enhancement. These findings also show that BC is not regionally enriched as it might be were climate to be a predominant factor in BC production, and seem to track land use more closely. Charcoal and BC concentrations were linearly correlated in only about half the soil profiles and neither BC nor charcoal were consistently correlated with chemical anthropogenic indicators such as P or Ca within soil profiles or specific regions. However, there was a statistical covariance between each of these parameters suggesting that each

  4. An index-based approach to assessing recalcitrance and soil carbon sequestration potential of engineered black carbons (biochars).

    Science.gov (United States)

    Harvey, Omar R; Kuo, Li-Jung; Zimmerman, Andrew R; Louchouarn, Patrick; Amonette, James E; Herbert, Bruce E

    2012-02-07

    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) 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.

  5. Effect of the secondary organic aerosol coatings on black carbon water uptake, cloud condensation nuclei activity, and particle collapse

    Science.gov (United States)

    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...

  6. Effects of carbon blacks with various structures on vulcanization and reinforcement of filled ethylene-propylene-diene rubber

    Directory of Open Access Journals (Sweden)

    2008-10-01

    Full Text Available The effects of carbon blacks on vulcanization and mechanical properties of filled ethylene-propylene-diene rubber (EPDM are investigated, by comparing with five types of rubber-grade carbon blacks. Curing kinetics is studied by rheometer and the results indicate that the curing characteristics are influenced by combination of surface area of carbon black and sulphur content on the filler surface, because the former one enhances the physical cross-linking and the latter one introduces the additional chemical cross-linking. Both the degree of cross-linking and cure rate increase with increasing surface area and sulphur content, whereas the optimum cure time and scorch time decrease. The reinforcing nature of the carbon black is assessed from mechanical measurements. It is suggested that the surface area of carbon blacks strongly affects the physical properties of EPDM/carbon black composites. Conductive carbon black (N472 can be used as desirable reinforcing filler due to the higher degree of cross-linking of EPDM with N472 than other EPDM/carbon black composites. The morphology and distribution of particles are studied by using scanning electron microscope. The sound reinforcing ability of N472 is also supported by scanning electron microscope due to the notable dispersibility of N472 within EPDM matrix. N472 ensures the EPDM/N472 composite the most conductive sample among the five composites.

  7. Two distinct patterns of seasonal variation of airborne black carbon over Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mo; Xu, Baiqing; Wang, Ninglian; Cao, Junji; Tie, Xuexi; Wang, Hailong; Zhu, Chongshu; Yang, Wei

    2016-12-01

    Airborne black carbon (BC) mass concentrations were measured from November 2012 to June 2013 at Ranwu and Beiluhe, located in the southeastern and central Tibetan Plateau, respectively. Monthly mean BC concentrations showawinter (November–February) high (413.2 ng m$-$3) and spring (March–June) low(139.1 ng m$-$3) at Ranwu, but in contrast awinter lowand spring high at Beiluhe (204.8 and 621.6 ng m$-$3, respectively). By examining the meteorological conditions at various scales, we found that themonthly variation of airborne BC over the southeastern Tibetan Plateau (TP) was highly influenced by regional precipitation and over the hinterland by winds. Local precipitation at both sites showed little impact on the seasonal variation of airborne BC concentrations. Potential BC source regions are identified using air mass backward trajectory analysis. At Ranwu, BC was dominated by the air masses from the northeastern India and Bangladesh in both winter and spring, whereas at Beiluhe it was largely contributed by air masses from the south slope of Himalayas in winter, and from the arid region in the north of the TP in spring. Thewinter and spring seasonal peak of BC in the southern TP is largely contributed by emissions from South Asia, and this seasonal variation is heavily influenced by the regional monsoon. In the northern TP, BC had high concentrations during spring and summer seasons, which is very likely associated with more efficient transport of BC over the arid regions on the north of Tibetan Plateau and in Central Asia. Airborne BC concentrations at the Ranwusampling site showed a significant diurnal cyclewith a peak shortly after sunrise followed by a decrease before noon in both winter and spring, likely shaped by local human activities and the diurnal variation of wind speed. At the Beiluhe sampling site, the diurnal variation of BC is different and less distinct.

  8. Biomass burning contribution to black carbon in the western United States mountain ranges

    Directory of Open Access Journals (Sweden)

    Y. Mao

    2011-05-01

    Full Text Available Forest fires are an important source to carbonaceous aerosols in the western United States (WUS. We quantify the relative contribution of biomass burning to black carbon (BC in the WUS mountain ranges by analyzing surface BC observations for 2006 from the Interagency Monitoring of PROtected Visual Environment (IMPROVE network using the GEOS-Chem global chemical transport model. Observed surface BC concentrations show broad maxima during late June to early November. Enhanced potassium concentrations and potassium/sulfur ratios observed during the high-BC events indicate a dominant biomass burning influence during the peak fire season. Model surface BC reproduces the observed day-to-day and synoptic variabilities in regions downwind of and near urban centers. Major discrepancies are found at elevated mountainous sites during the July–October when simulated BC concentrations are biased low by a factor of two. We attribute these biases largely to the underestimated and temporally misplaced biomass burning emissions of BC in the model. Additionally, we find that the biomass burning contribution to surface BC concentrations in the US likely was underestimated in a previous study using GEOS-Chem (Park et al., 2003, because of the unusually low planetary boundary layer (PBL heights and weak precipitation in the GEOS-3 meteorological reanalysis data used to drive the model. PBL heights from GEOS-4 and GEOS-5 reanalysis data are comparable to those from the North American Regional Reanalysis (NARR. Model simulations show improved agreements with the observations when driven by GEOS-5 reanalysis data, but model results are still biased low. The use of biomass burning emissions with diurnal cycle, synoptic variability, and plume injection has relatively small impact on the simulated surface BC concentrations in the WUS.

  9. Biomass burning contribution to black carbon in the Western United States Mountain Ranges

    Directory of Open Access Journals (Sweden)

    Y. H. Mao

    2011-11-01

    Full Text Available Forest fires are an important source to carbonaceous aerosols in the Western United States (WUS. We quantify the relative contribution of biomass burning to black carbon (BC in the WUS mountain ranges by analyzing surface BC observations for 2006 from the Interagency Monitoring of PROtected Visual Environment (IMPROVE network using the GEOS-Chem global chemical transport model. Observed surface BC concentrations show broad maxima during late June to early November. Enhanced potassium concentrations and potassium/sulfur ratios observed during the high-BC events indicate a dominant biomass burning influence during the peak fire season. Model surface BC reproduces the observed day-to day and synoptic variabilities in regions downwind of but near urban centers. Major discrepancies are found at elevated mountainous sites during the July-October fire season when simulated BC concentrations are biased low by a factor of two. We attribute these low biases largely to the underestimated (by more than a factor of two and temporally misplaced biomass burning emissions of BC in the model. Additionally, we find that the biomass burning contribution to surface BC concentrations in the USA likely was underestimated in a previous study using GEOS-Chem (Park et al., 2003, because of the unusually low planetary boundary layer (PBL heights in the GEOS-3 meteorological reanalysis data used to drive the model. PBL heights from GEOS-4 and GEOS-5 reanalysis data are comparable to those from the North American Regional Reanalysis (NARR. Model simulations show slightly improved agreements with the observations when driven by GEOS-5 reanalysis data, but model results are still biased low. The use of biomass burning emissions with diurnal cycle, synoptic variability, and plume injection has relatively small impact on the simulated surface BC concentrations in the WUS.

  10. Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways

    Directory of Open Access Journals (Sweden)

    K. Hara

    2008-05-01

    Full Text Available Measurement of black carbon (BC was carried out at Syowa station Antarctica (69° S, 39° E from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m−3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard conditions due to the approach of a cyclone and blocking event. The BC-rich air masses traveled from the lower troposphere of the Atlantic and Indian Oceans to Syowa (Antarctic coast. During the summer (November–February, the BC concentration showed a diurnal variation together with surface wind speed and increased in the katabatic wind from the Antarctic continent. Considering the low BC source strength in the Antarctic continent, the higher BC concentration in the continental air (katabatic wind might be caused by long range transport of BC via the free troposphere from mid- and low- latitudes. The seasonal variation of BC at Syowa had a maximum in August, while at the other coastal stations (Halley, Neumayer, and Ferraz and the continental station (Amundsen-Scott, the maximum occurred in October. This difference may result from different transport pathways and scavenging of BC by precipitation during the transport from the source regions. During the austral summer, long-range transport of BC via the free troposphere is likely to make an important contribution to the ambient BC concentration. The BC transport flux indicated that BC injection into the Antarctic region strongly depended on the frequency of storm (blizzard conditions. The seasonal variation of BC transport flux increased by 290 mg m−2 month−1 in winter–spring when blizzards frequently occurred, whereas the flux decreased to lower than 50 mg m−2 month−1 in the summer with infrequent blizzards.

  11. Automatic Method for Controlling the Iodine Adsorption Number in Carbon Black Oil Furnaces

    Directory of Open Access Journals (Sweden)

    Zečević, N.

    2008-12-01

    Full Text Available There are numerous of different inlet process factors in carbon black oil furnaces which must be continuously and automatically adjusted, due to stable quality of final product. The most important six inlet process factors in carbon black oil-furnaces are:1. volume flow of process air for combustion2. temperature of process air for combustion3. volume flow of natural gas for insurance the necessary heat for thermal reaction of conversionthe hydrocarbon oil feedstock in oil-furnace carbon black4. mass flow rate of hydrocarbon oil feedstock5. type and quantity of additive for adjustment the structure of oil-furnace carbon black6. quantity and position of the quench water for cooling the reaction of oil-furnace carbon black.The control of oil-furnace carbon black adsorption capacity is made with mass flow rate of hydrocarbon feedstock, which is the most important inlet process factor. Oil-furnace carbon black adsorption capacity in industrial process is determined with laboratory analyze of iodine adsorption number. It is shown continuously and automatically method for controlling iodine adsorption number in carbon black oil-furnaces to get as much as possible efficient control of adsorption capacity. In the proposed method it can be seen the correlation between qualitatively-quantitatively composition of the process tail gasses in the production of oil-furnace carbon black and relationship between air for combustion and hydrocarbon feedstock. It is shown that the ratio between air for combustion and hydrocarbon oil feedstock is depended of adsorption capacity summarized by iodine adsorption number, regarding to BMCI index of hydrocarbon oil feedstock.The mentioned correlation can be seen through the figures from 1. to 4. From the whole composition of the process tail gasses the best correlation for continuously and automatically control of iodine adsorption number is show the volume fraction of methane. The volume fraction of methane in the

  12. GI-core polymer parallel optical waveguide with high-loss, carbon-black-doped cladding for extra low inter-channel crosstalk.

    Science.gov (United States)

    Uno, Hisashi; Ishigure, Takaaki

    2011-05-23

    Graded-index (GI) polymer parallel optical waveguides with high-absorption, carbon-black-doped cladding are fabricated using the preform method in order to reduce the inter-channel crosstalk. The waveguides exhibit a lower inter-channel crosstalk (clad waveguides (~-33.7 dB) and maintain low propagation loss (0.029 dB/cm). We characterize the waveguides with different concentration of carbon black in order to confirm the required concentration (required absorption loss) for keeping the inter-channel crosstalk low enough. In addition, carbon-black-doped waveguides are fabricated directly on a substrate by means of a soft-lithography method. Crosstalk is sufficiently decreased despite the high scattering loss of the core material, while insertion loss is not increased. Furthermore, we fabricate a waveguide with a high-scattering-loss cladding to confirm the origin of low crosstalk in carbon-black-doped waveguides. We confirm that high scattering loss of cladding is not necessarily as effective for crosstalk reduction as high absorption loss of cladding.

  13. Bounding the role of black carbon in the climate system: A scientific assessment

    Science.gov (United States)

    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

  14. Black Ink of Activated Carbon Derived From Palm Kernel Cake (PKC)

    Science.gov (United States)

    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.

  15. Concentrations and solubility of selected trace metals in leaf and bagged black teas commercialized in Poland

    Directory of Open Access Journals (Sweden)

    L. Polechońska

    2015-09-01

    Full Text Available The objective of this study was to determine the concentrations of heavy metals in bagged and leaf black teas of the same brand and evaluate the percentage transfer of metals to tea infusion to assess the consumer exposure. Ten leaf black teas and 10 bagged black teas of the same brand available in Poland were analyzed for Zn, Mn, Cd, Pb, Ni, Co, Cr, Al, and Fe concentrations both in dry material and their infusion. The bagged teas contained higher amounts of Pb, Mn, Fe, Ni, Al, and Cr compared with leaf teas of the same brand, whereas the infusions of bagged tea contained higher levels of Mn, Ni, Al, and Cr compared with leaf tea infusions. Generally, the most abundant trace metals in both types of tea were Al and Mn. There was a wide variation in percentage transfer of elements from the dry tea materials to the infusions. The solubility of Ni and Mn was the highest, whereas Fe was insoluble and only a small portion of this metal content may leach into infusion. With respect to the acceptable daily intake of metals, the infusions of both bagged and leaf teas analyzed were found to be safe for human consumption.

  16. On the quantitative Amido Black B staining of protein spots in agar gel at low local protein concentrations

    NARCIS (Netherlands)

    Jansen, M.T.

    1962-01-01

    Protein spots in agar gel of identical protein content but different in surface area are found to bind different amounts of dye upon staining with Amido Black B. The lower the protein concentration within the agar gel, the more the Amido Black B content of the spot falls short of the value expected

  17. An overview of black carbon deposition and its radiative forcing over the Arctic

    Directory of Open Access Journals (Sweden)

    Ting-Feng Dou

    2016-09-01

    Full Text Available This paper gives an overview of the current understanding of the observations of black carbon (BC in snow and ice, and the estimates of BC deposition and its radiative forcing over the Arctic. Both of the observations and model results show that, in spring, the average BC concentration and the resulting radiative forcing in Russian Arctic > Canadian and Alaskan Arctic > Arctic Ocean and Greenland. The observed BC concentration presented a significant decrease trend from the Arctic coastal regions to the center of Arctic Ocean. In summer, due to the combined effects of BC accumulation and enlarged snow grain size, the averaged radiative forcing per unit area over the Arctic Ocean is larger than that over each sector of the Arctic in spring. However, because summer sea ice is always covered by a large fraction of melt ponds, the role of BC in sea ice albedo evolution during this period is secondary. Multi-model mean results indicate that the annual mean radiative forcing from all sources of BC in snow and ice over the Arctic was ∼0.17 W m−2. Wet deposition is the dominant removal mechanism in the Arctic, which accounts for more than 90% of the total deposition. In the last part, we discuss the uncertainties in present modeling studies, and suggest potential approaches to reduce the uncertainties.

  18. Simulation of black carbon in snow and its climate impact in the Canadian Global Climate Model

    Science.gov (United States)

    Namazi, M.; von Salzen, K.; Cole, J. N. S.

    2015-09-01

    A new physically based parameterisation of black carbon (BC) in snow was developed and implemented in the Canadian Atmospheric Global Climate Model (CanAM4.2). Simulated BC snow mixing ratios and BC snow radiative forcings are in good agreement with measurements and results from other models. Simulations with the improved model yield considerable trends in regional BC concentrations in snow and BC snow radiative forcings during the time period from 1950-1959 to 2000-2009. Increases in radiative forcings for Asia and decreases for Europe and North America are found to be associated with changes in BC emissions. Additional sensitivity simulations were performed in order to study the impact of BC emission changes between 1950-1959 and 2000-2009 on surface albedo, snow cover fraction, and surface air temperature. Results from these simulations indicate that impacts of BC emission changes on snow albedos between these 2 decades are small and not significant. Overall, changes in BC concentrations in snow have much smaller impacts on the cryosphere than the net warming surface air temperatures during the second half of the 20th century.

  19. Simulation of black carbon in snow and its climate impact in the Canadian Global Climate Model

    Directory of Open Access Journals (Sweden)

    M. Namazi

    2015-07-01

    Full Text Available A new physically-based parameterization of black carbon (BC in snow was developed and implemented in the Canadian Atmospheric Global Climate Model (CanAM4.2. Simulated BC snow mixing ratios and BC snow radiative forcings are in good agreement with measurements and results from other models. Simulations with the improved model yield considerable trends in regional BC concentrations in snow and BC snow radiative forcings during the time period from 1950–1959 to 2000–2009. Increases in radiative forcings for Asia and decreases for Europe and North America are found to be associated with changes in BC emissions. Additional sensitivity simulations were performed in order to study the impact of BC emission changes between 1950–1959 and 2000–2009 on surface albedo, snow cover fraction, and surface air temperature. Results from these simulations indicate that impacts of BC emission changes on snow albedos between these two decades are small and not significant. Overall, changes in BC concentrations in snow have much smaller impacts on the cryosphere than the net warming surface air temperatures during the second half of the 20th century.

  20. 1 Mixing state and absorbing properties of black carbon during Arctic haze

    Science.gov (United States)

    Zanatta, Marco; Gysel, Martin; Eleftheriadis, Kosas; Laj, Paolo; Hans-Werner, Jacobi

    2016-04-01

    The Arctic atmosphere is periodically affected by the Arctic haze occurring in spring. One of its particulate components is the black carbon (BC), which is considered to be an important contributor to climate change in the Arctic region. Beside BC-cloud interaction and albedo reduction of snow, BC may influence Arctic climate interacting directly with the solar radiation, warming the corresponding aerosol layer (Flanner, 2013). Such warming depends on BC atmospheric burden and also on the efficiency of BC to absorb light, in fact the light absorption is enhanced by mixing of BC with other atmospheric non-absorbing materials (lensing effect) (Bond et al., 2013). The BC reaching the Arctic is evilly processed, due to long range transport. Aging promote internal mixing and thus absorption enhancement. Such modification of mixing and is quantification after long range transport have been observed in the Atlantic ocean (China et al., 2015) but never investigated in the Arctic. During field experiments conducted at the Zeppelin research site in Svalbard during the 2012 Arctic spring, we investigated the relative precision of different BC measuring techniques; a single particle soot photometer was then used to assess the coating of Arctic black carbon. This allowed quantifying the absorption enhancement induced by internal mixing via optical modelling; the optical assessment of aged black carbon in the arctic will be of major interest for future radiative forcing assessment.Optical characterization of the total aerosol indicated that in 2012 no extreme smoke events took place and that the aerosol population was dominated by fine and non-absorbing particles. Low mean concentration of rBC was found (30 ng m-3), with a mean mass equivalent diameter above 200 nm. rBC concentration detected with the continuous soot monitoring system and the single particle soot photometer was agreeing within 15%. Combining absorption coefficient observed with an aethalometer and rBC mass

  1. Temporal variations of black carbon in Guangzhou, China, in summer 2006

    Directory of Open Access Journals (Sweden)

    R. L. Verma

    2010-07-01

    Full Text Available In situ measurements of the mass concentration of black carbon (BC and mixing ratios of carbon monoxide (CO and carbon dioxide (CO2 were made at Guangzhou, an urban measurement site in the Pearl River Delta (PRD, China, in July 2006. The average ± standard deviation (SD concentrations of BC, CO, and CO2 were 4.7± 2.3 μgC m−3, 798± 459 ppbv, and 400± 13 ppmv, respectively. The trends of these species were mainly controlled by synoptic-scale changes in meteorology during the campaign. Based on back trajectories, data are analyzed separately for two different air mass types representing northerly and southerly flows. The northerly air masses, which constituted ~25% of the campaign, originated mostly in the PRD and hence represent observations on regional scales. On the other hand, during southerly flow (~75%, the measurements were influenced by dilution due to cleaner marine air. The diurnal patterns of BC, CO, and CO2 exhibited peak concentrations during the morning and evening hours coinciding with rush-hour traffic. The ratios of OC/BC were lower during the morning hour peaks in the concentrations of primary pollutants due to their fresh emissions mainly from vehicular traffic in Guangzhou. The diurnal variations of BC observed in southerly air masses tended to follow the traffic patterns of heavy-duty vehicles (HDV in Guangzhou, while the roles of other sources need to be investigated. The slopes of ΔBC/ΔCO, ΔBC/ΔCO2, and ΔCO/ΔCO2 observed during northerly flows were 0.0045 μgC m−3/ppbv, 0.13 μgC m−3/ppmv, and 49.4 ppbv/ppmv, respectively, agreeing reasonably with their respective emission ratios derived from regional emission inventories.

  2. Improvement of the Rotary Dryers of Wet Pelletized Oil-Furnace Carbon Blacks

    Directory of Open Access Journals (Sweden)

    Zečević, M

    2010-05-01

    Full Text Available Due to the demand for higher production capacity and natural-gas energy savings, improvements were made to the rotary dryers in the drying process of wet pelletized oil-furnace carbon blacks. Since the rotary dryers were originally designed for drying semi-wet pelletized oil-furnace carbon blacks, they did not entirely satisfy optimal conditions for drying wet pelletized oil-furnace carbon blacks. Figure 1 shows the drying principle with key dimensions. The energy for drying the wet pelletized oil-furnace carbon blacks was provided by natural gas combustion in an open-furnace system with an uncontrolled feed of combustion air. Improvements on the rotary dryers were carried out by adjusting the excess oxygen in the gases passing through the butterfly valve on the dryer exhaust stack. By regulating the butterfly valve on the dryer exhaust stack, and applying the prescribed operations for drying wet pelletized oil furnace carbon blacks, the excess oxygen in the tail gases was adjusted in the range of φ = 3.0 % and 5.0 %, depending on the type of oil-furnace carbon blacks. Suggested also is installation of a direct-reverse automatic butterfly valve on the dryer exhaust stack to automatically determine the volume fraction of oxygen in the tail gas, and the volume flow rate of natural gas for combustion. The results the improvements carried out are shown in Tables 3 to 5. Table 2 shows the thermal calculations for the hood of the rotary dryer. Preheating of the process water in the temperature range of 70 °C and 80 °C is also recommended using the net heat from the oil-furnace process for wet pelletization. The results of preheating the process water are shown in Table 1. Depending on the type of oil-furnace carbon black, the aforementioned improvements resulted in natural gas energy savings ranging from 25 % to 35 % in relation to the average natural gas requirement in the drying process, and thus a reduction in carbon emissions of up to 40

  3. Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

    Science.gov (United States)

    Tang, N. W.; Kirchstetter, T.; Martien, P. T.; Apte, J.

    2015-12-01

    Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

  4. Associations between iron concentration and productivity in montane streams of the Black Hills, South Dakota

    Science.gov (United States)

    Hayer, Cari Ann; Holcomb, Benjamin M.; Chipps, Steven R.

    2013-01-01

    Iron is an important micronutrient found in aquatic systems that can influence nutrient availability (e.g., phosphorus) and primary productivity. In streams, high iron concentrations often are associated with low pH as a result of acid mine drainage, which is known to affect fish and invertebrate communities. Streams in the Black Hills of South Dakota are generally circumneutral in pH, yet select streams exhibit high iron concentrations associated with natural iron deposits. In this study, we examined relationships among iron concentration, priphyton biomass, macroinvertebrate abundance, and fish assemblages in four Black Hills streams. The stream with the highest iron concentration (~5 mg Fe/L) had reduced periphyton biomass, invertebrate abundance, and fish biomass compared to the three streams with lower iron levels (0.1 to 0.6 mg Fe/L). Reduced stream productivity was attributed to indirect effects of ferric iron Fe+++), owing to iron-hydroxide precipitation that influenced habitat quality (i.e., substrate and turbidity) and food availability (periphyton and invertebrates) for higher trophic levels (e.g., fish). Additionally, reduced primary and secondary production was associated with reduced standing stocks of salmonid fishes. Our findings suggested that naturally occurring iron deposits may constrain macroinvertebrate and fish production.

  5. Critical review of black carbon and elemental carbon source apportionment in Europe and the United States

    Science.gov (United States)

    Briggs, Nicole L.; Long, Christopher M.

    2016-11-01

    An increasing number of air pollution source apportionment studies in Europe and the United States have focused on the black carbon (BC) fraction of ambient particulate matter (PM) given its linkage with adverse public health and climate impacts. We conducted a critical review of European and US BC source apportionment studies published since 2003. Since elemental carbon (EC) has been used as a surrogate measure of BC, we also considered source apportionment studies of EC measurements. This review extends the knowledge presented in previous ambient PM source apportionment reviews because we focus on BC and EC and critically examine the differences between source apportionment results for different methods and source categories. We identified about 50 BC and EC source apportionment studies that have been conducted in either Europe or the US since 2003, finding a striking difference in the commonly used source apportionment methods between the two regions and variations in the assigned source categories. Using three dominant methodologies (radiocarbon, aethalometer, and macro-tracer methods) that only allow for BC to be broadly apportioned into either fossil fuel combustion or biomass burning source categories, European studies generally support fossil fuel combustion as the dominant ambient BC source, but also show significant biomass burning contributions, in particular in wintertime at non-urban locations. Among US studies where prevailing methods such as chemical mass balance (CMB) and positive matrix factorization (PMF) models have allowed for estimation of more refined source contributions, there are fewer findings showing the significance of biomass burning and variable findings on the relative proportion of BC attributed to diesel versus gasoline emissions. Overall, the available BC source apportionment studies provide useful information demonstrating the significance of both fossil fuel combustion and biomass burning BC emission sources in Europe and the US

  6. Enhanced Activated Carbon Cathode Performance for Microbial Fuel Cell by Blending Carbon Black

    KAUST Repository

    Zhang, Xiaoyuan

    2014-02-04

    Activated carbon (AC) is a useful and environmentally sustainable catalyst for oxygen reduction in air-cathode microbial fuel cells (MFCs), but there is great interest in improving its performance and longevity. To enhance the performance of AC cathodes, carbon black (CB) was added into AC at CB:AC ratios of 0, 2, 5, 10, and 15 wt % to increase electrical conductivity and facilitate electron transfer. AC cathodes were then evaluated in both MFCs and electrochemical cells and compared to reactors with cathodes made with Pt. Maximum power densities of MFCs were increased by 9-16% with CB compared to the plain AC in the first week. The optimal CB:AC ratio was 10% based on both MFC polarization tests and three electrode electrochemical tests. The maximum power density of the 10% CB cathode was initially 1560 ± 40 mW/m2 and decreased by only 7% after 5 months of operation compared to a 61% decrease for the control (Pt catalyst, 570 ± 30 mW/m2 after 5 months). The catalytic activities of Pt and AC (plain or with 10% CB) were further examined in rotating disk electrode (RDE) tests that minimized mass transfer limitations. The RDE tests showed that the limiting current of the AC with 10% CB was improved by up to 21% primarily due to a decrease in charge transfer resistance (25%). These results show that blending CB in AC is a simple and effective strategy to enhance AC cathode performance in MFCs and that further improvement in performance could be obtained by reducing mass transfer limitations. © 2014 American Chemical Society.

  7. Confronting the Global Climate Response to Black Carbon Aerosols with its Uncertainty

    Science.gov (United States)

    Mahajan, S.; Kovilakam, M.

    2015-12-01

    Black carbon aerosols (BC) modulate global temperatures and the hydrological cycle as well as regional climate. However, their radiative forcing is not well-constrained observationally and recent estimates of just the direct forcing ranges from 0.08 to 1.27 W/m2 - the upper limits of which puts BC second only to carbon dioxide in terms of radiative forcing. Consequently, the climate impacts of these heterogeneous short-lived forcing agents are highly uncertain. To establish the uncertainty in the climate response to BC, we conduct a suite of idealized experiments with the DOE/NCAR CESM1.0 model with the atmosphere component (CAM4) coupled to a Slab Ocean Model (SOM) forced separately with increasing BC concentrations covering a large swath of the estimated range of current BC radiative forcing. We find that the increase in BC results in global warming - with a sensitivity of 0.22 K/W/m2 including the semi-direct effects, decrease in global precipitation - despite the increase in global temperatures, a northwards shift of the ITCZ - along with an increase in cross-equatorial southwards energy transport, tropical expansion in the Northern Hemisphere - associated with BC induced mid-latitude warming, and an increase in precipitation during the Indian Monsoons - with the enhancement of the meridional tropospheric gradient, among other responses. Further, these global responses are near-linear functions of the increase in BC concentration, suggesting that the climate response to BC aerosols can be readily estimated if the uncertainty in BC can be constrained.

  8. Size distribution of black (BC) and total carbon (TC) in Vienna and Ljubljana.

    Science.gov (United States)

    Hitzenberger, R; Ctyroky, P; Berner, A; Tursic, J; Podkrajsek, B; Grgić, I

    2006-12-01

    During two campaigns in winter 2004, size segregated impactor samples (0.1-10 microm) and filter samples were taken in two Central European cities (Vienna, Austria and Ljubljana, Slovenia). The impactor samples were analyzed for major inorganic ions and short-chain organic acids, total carbon (TC) and black carbon (BC). Maximum concentrations of total mass were 71.6 microg m(-3) in Vienna and 73.1 microg m(-3) in Ljubljana. Minimum concentrations in Vienna were only half those in Ljubljana. The BC content of the aerosol was similar (ca. 8%), but the BC/TC ratio was higher in Vienna than in Ljubljana (0.39 vs. 0.29), reflecting the different contribution of diesel traffic emissions. The mass median diameters of the submicron size distributions of all major fractions (total mass, TC, BC and SO(4)(2-)) were smaller in Vienna (0.43 microm, 0.41 microm, 0.38 microm and 0.48 microm, respectively) than in Ljubljana (0.55 microm, 0.44 microm, 0.42 microm and 0.60 microm, respectively). Impactor/filter ratios for total mass were 0.79 in Vienna and 0.82 in Ljubljana, while the ratios for BC were 0.56 in Vienna and 0.49 in Ljubljana. An estimation of the mixing state of accumulation mode BC indicated that 33% and 37% of BC, respectively, are mixed externally to the aerosol in the accumulation size range in Vienna and Ljubljana.

  9. Penelitian pengaruh naphthenic oil dan carbon black terhadap sifat kekerasan lis kaca mobil

    Directory of Open Access Journals (Sweden)

    Any Setyaningsih

    1999-07-01

    Full Text Available This research have a purpose to know influence naphthenic oil and car bon black about properties hardness weather strip for auto mobile. Compound wea ther strip for auto mobile make for Natural Rubber (RSS and sintetic rubber (SBR 1502 with in creasing ingrediens such plasticizer, activator, filler, anti oxidant, accelerator and vulkanizing agent. Compount formula making variation naphthenic oil 3,5 and 7 part along with carbon black 45,50 and 55 part result hardness test with value 67 shore A for compount with naphthenic oil 7 part and carbon black 50 part and after perform make in to fill requrements SNI 1490 – 89 A weather strip auto mobile.

  10. Changes in Snow Albedo Resulting from Snow Darkening Caused by Black Carbon

    Science.gov (United States)

    Engels, J.; Kloster, S.; Bourgeois, Q.

    2014-12-01

    We investigate the potential impact of snow darkening caused by pre-industrial and present-day black carbon (BC) emissions on snow albedo and subsequently climate. To assess this impact, we implemented the effect of snow darkening caused by BC emitted from natural as well as anthropogenic sources into the Max Planck Institute for Meteorology Earth System Model (MPI-M ESM). Considerable amounts of BC are emitted e.g. from fires and are transported through the atmosphere for several days before being removed by rain or snow precipitation in snow covered regions. Already very small quantities of BC reduce the snow reflectance significantly, with consequences for snow melting and snow spatial coverage. We implemented the snow albedo reduction caused by BC contamination and snow aging in the one layer land surface component (JSBACH) of the atmospheric general circulation model ECHAM6, developed at MPI-M. For this we used the single-layer simulator of the SNow, Ice, and Aerosol Radiation (SNICAR-Online (Flanner et al., 2007); http://snow.engin.umich.edu) model to derive snow albedo values for BC in snow concentrations ranging between 0 and 1500 ng(BC)/g(snow) 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 deposition rates of BC on snow are prescribed from previous ECHAM6-HAM simulations for two time periods, pre-industrial (1880-1889) and present-day (2000-2009), respectively. We perform a sensitivity study regarding the scavenging of BC by snow melt. To evaluate the newly implemented albedo scheme we will compare the modeled black carbon in snow concentrations to observed ones. Moreover, we will show the impact of the BC contamination and snow aging on the simulated snow albedo. The

  11. Simulating the global atmospheric black carbon cycle: a revisit to the contribution of aircraft emissions

    Directory of Open Access Journals (Sweden)

    J. Hendricks

    2004-06-01

    Full Text Available The black carbon (BC burden of the upper troposphere and lowermost stratosphere (UTLS is investigated with the general circulation model (GCM ECHAM4. The special focus is the contribution of aircraft emissions to the UTLS BC loading. Previous studies on the role of aircraft emissions in the global BC cycle either neglect BC sources located at the Earth's surface or simplify the BC cycle by assuming pre-defined BC residence times. Here, the global BC cycle including emissions, transport, and removal is explicitly simulated. The BC emissions considered include surface sources as well as BC from aviation. This enables a consistent calculation of the relative contribution of aviation to the global atmospheric BC cycle. As a further extension to the previous studies, the aviation-induced perturbation of the UTLS BC particle number concentration is investigated. Several sensitivity studies were performed to evaluate the uncertainties associated with the model predictions. The simulated UTLS BC concentrations are compared to in-situ observations. The simulations suggest that the large-scale contribution of aviation to the UTLS BC mass budget typically amounts to only a few percent, even in the most frequented flight regions. The aviation impact far away from these regions is negligible. The simulated aircraft contributions to the UTLS BC particle number concentration are much larger compared to the corresponding mass perturbations. The simulations suggest that aviation can cause large-scale increases in the UTLS BC particle number concentration of more than 30% in regions highly frequented by aircraft. The relative effect shows a pronounced annual variation with the largest relative aviation impact occurring during winter.

  12. Simulating the global atmospheric black carbon cycle: a revisit to the contribution of aircraft emissions

    Directory of Open Access Journals (Sweden)

    J. Hendricks

    2004-01-01

    Full Text Available The black carbon (BC burden of the upper troposphere and lowermost stratosphere (UTLS is investigated with the general circulation model (GCM ECHAM4. The special focus is the contribution of aircraft emissions to the UTLS BC loading. Previous studies on the role of aircraft emissions in the global BC cycle either neglect BC sources located at the Earth's surface or simplify the BC cycle by assuming pre-defined BC residence times. Here, the global BC cycle including emissions, transport, and removal is explicitly simulated. The BC emissions considered include surface sources as well as BC from aviation. This enables a consistent calculation of the relative contribution of aviation to the global atmospheric BC cycle. As a further extension to the previous studies, the aviation-induced perturbation of the UTLS BC particle number concentration is investigated. The uncertainties associated with the model predictions are evaluated by means of several sensitivity studies. Especially, the sensitivity of the results to different assumptions on the BC hygroscopic properties is analysed. The simulated UTLS BC concentrations are compared to in-situ observations. The simulations suggest that the large-scale contribution of aviation to the UTLS BC mass budget typically amounts to only a few percent, even in the most frequented flight regions. The aviation impact far away from these regions is negligible. The simulated aircraft contributions to the UTLS BC particle number concentration are much larger compared to the corresponding mass perturbations. The simulations suggest that aviation can cause large-scale increases in the UTLS BC particle number concentration of more than 30% in regions highly frequented by aircraft. The relative effect shows a pronounced annual variation with the largest relative aviation impact occurring during winter.

  13. Attribution of aerosol light absorption to black carbon, brown carbon, and dust in China – interpretations of atmospheric measurements during EAST-AIRE

    Directory of Open Access Journals (Sweden)

    B. J. Huebert

    2008-06-01

    Full Text Available Black carbon, brown carbon, and mineral dust are three of the most important light absorbing aerosols. Their optical properties differ greatly and are distinctive functions of the wavelength of light. Most optical instruments that quantify light absorption, however, are unable to distinguish one type of absorbing aerosol from another. It is thus instructive to separate total absorption from these different light absorbers to gain a better understanding of the optical characteristics of each aerosol type. During the EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment campaign near Beijing, we measured light scattering using a nephelometer, and light absorption using an aethalometer and a particulate soot absorption photometer. We also measured the total mass concentrations of carbonaceous (elemental and organic carbon and inorganic particulates, as well as aerosol number and mass distributions. We were able to identify periods during the campaign that were dominated by dust, biomass burning, fresh (industrial chimney plumes, other coal burning pollution, and relatively clean (background air for Northern China. Each of these air masses possessed distinct intensive optical properties, including the single scatter albedo and Ångstrom exponents. Based on the wavelength-dependence and particle size distribution, we apportioned total light absorption to black carbon, brown carbon, and dust; their mass absorption efficiencies at 550 nm were estimated to be 9.5, 0.5, and 0.03 m2/g, respectively. While agreeing with the common consensus that BC is the most important light absorber in the mid-visible, we demonstrated that brown carbon and dust could also cause significant absorption, especially at shorter wavelengths.

  14. Analysis of the Interphase on Carbon Black Formed in High Voltage Batteries

    DEFF Research Database (Denmark)

    Younesi, Reza; Christiansen, Ane Sælland; Scipioni, Roberto;

    2015-01-01

    Carbon black (CB) additives commonly used to increase the electrical conductivity of electrodes in Li-ion batteries are generally believed to be electrochemically inert additives in cathodes. Decomposition of electrolyte in the surface region of CB in Li-ion cells at high voltages up to 4.9 V...

  15. Evaluation of Methods for the Determination of Black Carbon Emissions from an Aircraft Gas Turbine Engine

    Science.gov (United States)

    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 ...

  16. Carbon black nanoparticles and vascular dysfunction in cultured endothelial cells and artery segments

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Mikkelsen, Lone; Folkmann, Janne K;

    2012-01-01

    Exposure to small size particulates is regarded as a risk factor for cardiovascular disease. We investigated effects of exposure to nanosized carbon black (CB) in human umbilical vein endothelial cells (HUVECs) and segments of arteries from rodents. The CB exposure was associated with increased...

  17. Electrical Percolation of Carbon Black Filled Poly (ethylene oxide) Composites in Relation to the Matrix Morphology

    Institute of Scientific and Technical Information of China (English)

    Gen Shui CHENG; Ji Wen HU; Ming Qiu ZHANG; Ming Wei LI; Ding Shu XIAO; Min Zhi RONG

    2004-01-01

    The present work studies the electrical conduction performance of carbon black (CB)filled poly(ethylene oxide) (PEO) composites. The addition of CB leads to reduced matrix crystallinity as the fillers which are partly situated inside the lamellae and hinder the growth of PEO crystallites. As a result, the electrical percolation behavior is related with the matrix morphology.

  18. Influence of nanoclay-carbon black hybrid fillers on cure and properties of natural rubber compounds

    NARCIS (Netherlands)

    Sapkota, J.; Poikelispää, M.; Das, A.; Dierkes, W.K.; Vuorinen, J.

    2013-01-01

    The influence of organically modified nanoclay-carbon black (CB) hybrid filler on the curing behavior of natural rubber (NR) was explored in this investigation. Here an effort was paid to understand the curing kinetics of organomodified nanoclay filled rubber compounds. On the basis of two different

  19. Simplifying the calculation of light scattering properties for black carbon fractal aggregates

    Directory of Open Access Journals (Sweden)

    A. J. A. Smith

    2014-02-01

    Full Text Available Black carbon fractal aggregates have complicated shapes that make the calculation of their optical properties particularly computationally expensive. Here, a method is presented to estimate fractal aggregate light scattering properties by optimising simplified models to full light scattering calculations. It is found that there are no possible spherical models (at any size or refractive index that well represent the light scattering in the visible, or near-thermal infrared. As such, parameterisations of the light scattering as a function of the number of aggregate particles is presented as the most pragmatic choice for modelling distributions of black carbon when the large computational overheads of rigorous scattering calculations cannot be justified. This parameterisation can be analytically integrated to provide light scattering properties for log-normal distributions of black carbon fractal aggregates and return extinction cross-sections with 0.1% accuracy for typical black carbon size distributions. Scattering cross-sections and the asymmetry parameter can be obtained to within 3%.

  20. Investigation of reinforcement of the modified carbon black from wasted tires by nuclear magnetic resonance

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jie; YANG Yong-rong; REN Xiao-hong; STAPF Siegfried

    2006-01-01

    Pyrolysis has the potential of transforming waste into recyclable products. Pyrolytic carbon black (PCB) is one of the most important products from the pyrolysis of used tires. Techniques for surface modifications of PCB have been developed. One of the most significant applications for modified PCB is to reinforce the rubber matrix to obtain high added values. The transverse relaxation and the chain dynamics of vulcanized rubber networks with PCB and modified PCB were studied and compared with those of the commercial carbon blacks using selective 1H transverse relaxation (T2) experiments and dipolar correlation effect (DCE) experiments on the stimulated echo. Demineralization and coupling agent modification not only intensified the interactions between the modified PCB and the neighboring polyisoprene chains, but also increased the chemical cross-link density of the vulcanized rubber with modified PCB. The mechanical testing of the rubbers with different kinds of carbon blacks showed that the maximum strain of the rubber with modified PCB was improved greatly. The mechanical testing results confirmed the conclusion obtained by nuclear magnetic resonance (NMR). PCB modified by the demineralization and NDZ-105 titanate coupling agent could be used to replace the commercial semi-reinforcing carbon black.

  1. Quantification methods of Black Carbon: Comparison of Rock-Eval analysis with traditional methods

    NARCIS (Netherlands)

    Poot, A.; Quik, J.T.K.; Veld, H.; Koelmans, A.A.

    2009-01-01

    Black Carbon (BC) quantification methods are reviewed, including new Rock-Eval 6 data on BC reference materials. BC has been reported to have major impacts on climate, human health and environmental quality. Especially for risk assessment of persistent organic pollutants (POPs) it is important to ac

  2. Effects of prenatal exposure to nanoparticles titanium dioxide and carbon black on female germline DNA stability

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner

    are actively dividing. The aim of this PhD study was to determine if two widely used nanoparticles titanium dioxide UV-Titan and carbon black Printex 90 induce ESTR mutations in the germ cells of prenatally exposed females. Pregnant generation P mice were exposed to ~42 mg UV-Titan/m3/1 h/d during gestation...

  3. Effects of occupational exposure to carbon black on peripheral white blood cell counts and lymphocyte subsets

    NARCIS (Netherlands)

    Dai, Yufei; Niu, Yong; Duan, Huawei; Bassig, Bryan A; Ye, Meng; Zhang, Xiao; Meng, Tao; Bin, Ping; Jia, Xiaowei; Shen, Meili; Zhang, Rong; Hu, Wei; Yang, Xiaofa; Vermeulen, Roel; Silverman, Debra; Rothman, Nathaniel; Lan, Qing; Yu, Shanfa; Zheng, Yuxin

    2016-01-01

    The International Agency for Research on Cancer has classified carbon black (CB) as a possible (Group 2B) human carcinogen. Given that most CB manufacturing processes result in the emission of various types of chemicals, it is uncertain if the adverse health effects that have been observed in CB-exp

  4. Nanoscale Interactions between Engineered Nanomaterials and Black Carbon (Biochar) in Soil

    Science.gov (United States)

    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...

  5. Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

    Directory of Open Access Journals (Sweden)

    Huaigang Cheng

    2014-01-01

    Full Text Available Ultrafine calcium carbonate is a widely used cheap additive. The research is conducted in low degree supersaturation solution in order to study the polymorphic phases’ change and its factors of the calcium carbonate precipitate in the ammonification-carbonization process of the solution with calcium. Fine particles of calcium carbonate are made in the solution containing 0.015 mol/L of Ca2+. Over 98% of the calcium carbonate precipitate without ammonification resembles the morphology of calcite, while the introduction of ammonia can benefit the formation of vaterite. It was inferred that the main cause should be serious partial oversaturation or steric effects. Ammonia also helps to form the twin spherical calcium carbonate. However, particles formed in the process of ammonification-carbonization in solution with low concentration degree of calcium are not even with a scale of the particle diameter from 5 to 12 μm. Inorganic salts, alcohol, or organic acid salts have significant controlling effect on the particle diameter of calcium carbonate and can help to decrease the particle diameter to about 3 μm. Anionic surfactants can prevent the conglobation of calcium carbonate particles and shrink its diameter to 500 nm–1 μm.

  6. Continuous measurement of carbon black in a densely populated area of Mexico City

    Science.gov (United States)

    Peralta, Oscar; Ortinez, Abraham; Castro, Telma; Espinosa, Maria; Saavedra, Isabel; Alvarez, Harry; Basaldud, Roberto; Paramo, Víctor; Martínez, Amparo

    2015-04-01

    The black carbon (BC) is a byproduct of burning fossil fuels and is an important short-lived climate forcer because it absorbs solar radiation altering the Earth's radiative budget and climate. It is also an atmospheric pollutant that promotes reactions of other compounds in the atmosphere. Despite its importance for health and climate, in Mexico there are very few studies on ambient concentrations of BC in urban areas and virtually no information of continuous measurements over long periods (more than a month of measurements). So, in order to develop more efficient local and regional mitigation strategies and policies that allow reducing ambient concentrations of BC, it is necessary to know BC seasonal evolution, contribution to radiative budget and impacts on health. This study shows continuous measurements (from July 2013 to July 2014) of BC to perform an analysis of seasonal variations. The selected monitoring site is located at Iztapalapa, a densely populated area with high traffic on the southeastern part of Mexico City. BC concentrations were obtained by two aethalometers (Magee Scientific Company, models AET31 and AET42) placed 15 meters above the ground. The aethalometers operate in the wavelength range of 370-950 nm and use a standard value of mass absorption coefficient MAC = 10.8 m2/g to calculate BC environmental concentration. To correct the aethalometers readings to the conditions of Mexico City, it was employed MAC = to 6.7 m2/g, which was determined for PM2.5 with a carbon analyzer (UIC, Inc.) and represents the mass absorption coefficient of soot emitted in Mexico City. The average value of the corrected concentration of BC in Mexico City during the period from July 2013 to July 2014 was 5.39 ± 1.89 μg/m3 (1.6 higher than readings recorded by aethalometers), which is greater than that measured in Shanghai in 2014 (annual average 2.33 μg/m3) and those reported for some U.S. cities; the value implies a potential danger to the health of

  7. Evaluating the air quality impacts of the 2008 Beijing Olympic Games: On-road emission factors and black carbon profiles

    Science.gov (United States)

    Wang, Xing; Westerdahl, Dane; Chen, Lung Chi; Wu, Ye; Hao, Jiming; Pan, Xiaochuan; Guo, Xinbiao; Zhang, K. Max

    The aggressive traffic interventions and emission control measures implemented to improve air quality during the 2008 Beijing Olympic Games created a valuable case study to evaluate the effectiveness of these measures on mitigating air pollution and protecting public health. In this paper, we report the results from our field campaign in summer 2008 on the on-road emission factors of carbon monoxide, black carbon (BC) and ultrafine particles (UFP) as well as the ambient BC concentrations. The fleet average emission factors for light-duty gasoline vehicles (LDGV) showed considerable reduction in the Olympic year (2008) compared to the pre-Olympic year (2007). Our measurement of Black Carbon (BC), a primary pollutant, at different elevations at the ambient site suggests consistent decrease in BC concentrations as the height increased near the ground level, which indicates that the nearby ground level sources, probably dominated by traffic, contributed to a large portion of BC concentrations in the lower atmospheric layer in Beijing during summertime. These observations indicate that people living in near ground levels experience higher exposures than those living in higher floors in Beijing. The BC diurnal patterns on days when traffic control were in place during the Olympic Games were compared to those on non-traffic-control days in both 2007 and in 2008. These patterns strongly suggest that diesel trucks are a major source of summertime BC in Beijing. The median BC concentration on Olympic days was 3.7 μg m -3, which was dramatically lower than the value on non-traffic-control days, indicating the effectiveness of traffic control regulations in BC reduction in Beijing.

  8. The carbon-nitrogen balance of the nodule and its regulation under elevated carbon dioxide concentration.

    Science.gov (United States)

    Libault, Marc

    2014-01-01

    Legumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2). In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency.

  9. Detection and characterization of nanomaterials released in low concentrations during multi-walled carbon nanotube spraying process in a cleanroom.

    Science.gov (United States)

    Ji, Jun Ho; Woo, Daekwang; Lee, Seung-Bok; Kim, Taesung; Kim, Duckjong; Kim, Jae-Hyun; Bae, Gwi-Nam

    2013-12-01

    Release of nanomaterials was assessed in a cleanroom workplace designed for the handling of multi-walled carbon nanotubes. During the process, the nanotubes were sprayed in a chamber fitted with an exhaust duct system. The front door of the spraying chamber was completely closed, but rear end of the chamber was partially open. Throughout a series of spray processes, three detectors - an optical particle counter, a nanoparticle aerosol monitor, and an aethalometer - counted and characterized particles escaping the chamber. Concentrations of particle surface area and black carbon emitted by the spraying were assessed assuming zero background aerosol concentration in the cleanroom. Very low concentrations of black carbon, 0.4 μg/m(3), were observed. In conclusion, in a cleanroom, low concentrations of nanomaterials were detected to be emitted from a spraying chamber into the workplace. The level of particles reaching the workplace was sufficiently low to have made their detection difficult in a normal environment. Both target nanomaterial and non-intended incidental nanomaterials were released during spraying. Despite the use of exhaust duct system in the process chamber, workers would be exposed to some particles if the chamber were partially open. The exhaust duct system was not enough to remove all the particles released in the chamber.

  10. Morphology and Optical Properties of Black-Carbon Particles Relevant to Engine Emissions

    Science.gov (United States)

    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.

  11. Characterisation of surface ionisation and adsorption of phenol and 4-nitrophenol on non-porous carbon blacks

    OpenAIRE

    Carrott, Peter; Carrott, Manuela; Vale, Tania; Valente Nabais, Joao; Mourao, Paulo

    2008-01-01

    The adsorption of phenol and 4-nitrophenol from aqueous solutions by carbon blacks was studied. Particular attention was paid to the characterisation of the surface chemistry and ionisation of the carbon blacks by use of a simple carbon surface ionisation model, as well as the use of a normalised form of the Freundlich equation for the analysis of the adsorption isotherms. The results indicated that the solutes interact directly with the graphene layers and that the adsorpti...

  12. Sewage sludge composting simulation as carbon/nitrogen concentration change

    Institute of Scientific and Technical Information of China (English)

    Nassereldeen Kabbashi

    2011-01-01

    Available composting models do not describe accurately the dynamics of composting processes.Difficulty in modeling composting processes is attributed mainly to the unpredicted change in process rate caused by change in activation energy value (E).This article presented the results of an attempt made to utilize patterns of change in carbon,nitrogen and temperature profiles to model sewage sludge composting process as a multi-stage process.Results of controlled sewage sludge composting experiments were used in th estudy.All the experiments were carried out as batch experiments in a 300-liter Horizontal Drum Bioreactor (HDB).Analysis of the profiles of carbon,nitrogen and temperature has indicated that there were clear patterns that could be used to develop simple models of the process,the initial C/N ratio was between 7-8 and the final C/N ratio of the compost in most experiments were found to be around 15.0,indicating the compost was fully matured and could be used safely for agricultural purpose.Electrical conductivity of composting material decreased from 1.83 to 1.67 dS/m,after a period,it increased gradually from 2.01 to 2.23 dS/m and remained at around 2.33 dS/m till the end of composting.It is found that change in the concentration of total carbon can reasonably be described by three constant process rate coefficients (k1,k2,k3).It is found that the process starts with a certain process rate coefficient (k1) and continues until peak temperature is reached,then it reaches lower process (k2) in the declining phase of the thermophilic stage,and finally it proceeds with a faster process rate (k3) when maturation is reached.Change in the concentration of total nitrogen has shown to have the same patterns of change as carbon.

  13. Concentration-mediated multicolor fluorescence polymer carbon dots.

    Science.gov (United States)

    Jeong, Chan Jin; Lee, Gibaek; In, Insik; Park, Sung Young

    2016-05-01

    Polymer dots (PDs) showing concentration-mediated multicolor fluorescence were first prepared from sulfuric acid-treated dehydration of Pluronic® F-127 in a single step. Pluronic-based PDs (P-PDs) showed high dispersion stability in solvent media and exhibited a fluorescence emission that was widely tunable from red to blue by adjusting both the excitation wavelengths and the P-PD concentration in an aqueous solution. This unique fluorescence behavior of P-PDs might be a result of cross-talk in the fluorophores of the poly(propylene glycol)-rich core inside the P-PD through either energy transfer or charge transfer. Reconstruction of the surface energy traps of the P-PDs mediated through aggregation may lead to a new generation of carbon-based nanomaterials possessing a fluorescence emission and tunable by adjusting the concentration. These structures may be useful in the design of multifunctional carbon nanomaterials with tunable emission properties according to a variety of internal or external stimuli.

  14. Inference of Spatiotemporal Distribution of Black Carbon Aerosols over Northern Pacific from Satellite Observations (2005-2012)

    Science.gov (United States)

    Liu, J.; Li, Z.; Mauzerall, D. L.; Fan, S.; Horowitz, L. W.; He, C.; Yi, K.; Tao, S.

    2015-12-01

    Knowledge on the spatiotemporal distribution of black carbon aerosol over the Northern Pacific is limited by a deficiency of observations. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 is the most comprehensive data source available and it reveals a 2 to 10 times overestimates of BC by current global models. Incorporation and assimilation of more data sources is needed to increase our understanding of the spatiotemporal distribution of black carbon aerosol and its corresponding climate effects. Based on measurements from aircraft campaigns and satellites, a robust association is observed between BC concentrations and satellite retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R2 > 0.7). Such robust relationships indicate that BC aerosols share a similar emission sources, evolution processes and transport characteristics with other pollutants measured by satellite observations. It also establishes a basis to derive a satellite-based proxy (BC*) over remote oceans. The inferred satellite-based BC* shows that Asian export events in spring bring much more BC aerosols to the mid-Pacific than occurs in other seasons. In addition, inter-annual variability of BC* is seen over the Northern Pacific, with abundances correlated to the springtime Pacific/North American (PNA) index. The inferred BC* dataset also indicates a widespread overestimation of BC loadings by models over most remote oceans beyond the Pacific. Our method presents a novel approach to infer BC concentrations by combining satellite and aircraft observations.

  15. Capturing vertical profiles of aerosols and black carbon over the Indian Ocean using autonomous unmanned aerial vehicles

    Directory of Open Access Journals (Sweden)

    C. E. Corrigan

    2008-02-01

    Full Text Available Measurements of the vertical distribution of aerosol properties provide essential information for generating more accurate model estimates of radiative forcing and atmospheric heating rates compared with employing remotely sensed column averaged properties. A month long campaign over the Indian Ocean during March 2006 investigated the interaction of aerosol, clouds, and radiative effects. Routine vertical profiles of aerosol and water vapor were determined using autonomous unmanned aerial vehicles equipped with miniaturized instruments. Comparisons of these airborne instruments with established ground-based instruments and in aircraft-to-aircraft comparisons demonstrated an agreement within 10%.

    Aerosol absorption optical depths measured directly using the unmanned aircraft differed from columnar AERONET sun-photometer results by only 20%. Measurements of total particle concentration, particle size distributions, aerosol absorption and black carbon concentrations are presented along with the trade wind thermodynamic structure from the surface to 3000 m above sea level. Early March revealed a well-mixed layer up to the cloud base at 500 m above mean sea level (m a.s.l., followed by a decrease of aerosol concentrations with altitude. The second half of March saw the arrival of a high altitude plume existing above the mixed layer that originated from a continental source and increased aerosol concentrations by more than tenfold, yet the surface air mass showed little change in aerosol concentrations and was still predominantly influenced by marine sources. Black carbon concentrations at 1500 m above sea level increased from 70 ng/m3 to more than 800 ng/m3 with the arrival of this polluted plume. The absorption aerosol optical depth increased from as low as 0.005 to as much as 0.035 over the same period. The spectral dependence of the aerosol absorption revealed an absorption Angstrom exponent of 1.0, which is typical

  16. Capturing vertical profiles of aerosols and black carbon over the Indian Ocean using autonomous unmanned aerial vehicles

    Directory of Open Access Journals (Sweden)

    C. E. Corrigan

    2007-08-01

    Full Text Available Measurements of the vertical distribution of aerosol properties provide essential information for generating more accurate model estimates of radiative forcing and atmospheric heating rates compared with employing remotely sensed column averaged properties. A month long campaign over the Indian Ocean during March 2006 investigated the interaction of aerosol, clouds, and radiative effects. Routine vertical profiles of aerosol and water vapor were determined using autonomous unmanned aerial vehicles equipped with miniaturized instruments. Comparisons of these airborne instruments with established ground-based instruments and in aircraft-to-aircraft comparisons demonstrated an agreement within 10%.

    Aerosol absorption optical depths measured directly using the unmanned aircraft differed from columnar AERONET sun-photometer results by only 20%. Measurements of total particle concentration, particle size distributions, aerosol absorption and black carbon concentrations are presented along with the trade wind thermodynamic structure from the surface to 3000 m above sea level. Early March revealed a well-mixed layer up to the cloud base at 500 m above mean seal level (m a.s.l., followed by a decrease of aerosol concentrations with altitude. The second half of March saw the arrival of a high altitude plume existing above the mixed layer that originated from a continental source and increased aerosol concentrations by more than tenfold, yet the surface air mass showed little change in aerosol concentrations and was still predominantly influenced by marine sources. Black carbon concentrations at 1500 m above sea level increased from 70 ng/m³ to more than 800 ng/m³ with the arrival of this polluted plume. The absorption aerosol optical depth increased from as low as 0.005 to as much as 0.035 over the same period. The spectral dependence of the aerosol absorption revealed an absorption Angstrom exponent of 1.0, which is typical of an aerosol with

  17. Organic carbon concentrations and stocks in Romanian mineral forest soils

    Directory of Open Access Journals (Sweden)

    Lucian C. Dincă

    2012-12-01

    Full Text Available Estimating soils organic carbon stock and its change in time is an actual concern for scientists and climate change policy makers. The present article firstly focus on determination of C stocks in Romania on forest soil types, as well as development of the spatial distribution mapping using a Geographic Information System (GIS and also the secondly on the quantification of uncertainty associated with currently available data on C concentration on forest soils geometrical layers. Determination of C stock was done based on forest management plans database created over 2000-2006. Unlike original database, the data for this study was harmonized on following depths: 0-10 cm, 10-20 cm, 20-40 cm, and > 40 cm. Then, the obtained values were grouped by soil types, resulting average values for the main forest soils from Romania. A soil area weighted average value of 137 t/ha is calculated for Romania, in the range of estimations for other European geographic and climatic areas. The soils that have the largest amount of organic carbon are andosols, vertisols, entic and haplic podzols, whereas the ones that have the smallest values of organic carbon are solonetz and solonchaks. Although current assessment relies on very large number of samples from the forest management planning database, the variability of C concentration remains very large, ~40-50% for coefficient the variation and ~100% of the average, when defining the range of 95% of entire soil population, rather showing the variability than uncertainty of the average estimated. Best fit for C concentration on geometric layers in any forest soil is asymmetric, associated with log-normal distributions.

  18. Heterogeneous atoms in laser-induced synthesis of carbon black

    Science.gov (United States)

    Popovici, E.; Gavrila Florescu, L.; Soare, I.; Scarisoreanu, M.; Sandu, I.; Prodan, G.; Fleaca, C. T.; Morjan, I.; Voicu, I.

    2009-03-01

    Based on a high temperature hydrocarbon/heterogeneous atoms system of well-established composition, the formation of carbon nanostructures by laser-induced pyrolysis is related to the presence of heteroatoms in the reactants. In this paper, the goal is to underline the influence of some heteroatoms on the morphology and functionalizing nanostructured carbon materials by changing both gas composition and experimental parameters, with the focus to drive these materials into a regime where they can naturally interface with the surrounding matter. To investigate, in the versatile laser pyrolysis method, how to in situ modulate - through the presence of heterogeneous atoms - the characteristics of carbon nanopowders claimed by specific application is a challenge. Some preliminary results confirm experimentally their particular behavior during interaction with polymer matrices of some nanocomposites.

  19. Sensitivity of climate effects of black carbon in China to its size distributions

    Science.gov (United States)

    Ma, Xingxing; Liu, Hongnian; Liu, Jane J.; Zhuang, Bingliang

    2017-03-01

    The climate effects of black carbon (BC) aerosols are sensitive to BC size distributions and this sensitivity over China is studied using a regional climate model, namely RIEMS2.0. A new size-resolved scheme is developed based on observational data. The simulated BC concentrations with the new scheme are better compared with the observation than the previous uniform scheme, which is likely to overestimate BC concentrations, radiative forcings, and warming effects in many regions of China due to its simple assumption on BC size. The simulation with the size-resolved scheme suggests a reduction of the all-sky radiative forcing of BC at the top of atmosphere (TOA) by 0-0.25 W m- 2 over the most study domain. Correspondingly, the warming effect of BC is weakened by - 0.04 to - 0.16 K over most parts of South China and North China. The difference in BC-induced precipitation between the two schemes varies irregularly from region to region, ranging from - 2.8 to 2.8 mm d- 1. With the size-resolved scheme, the BC radiative properties and the climate effects are reassessed and the means (ranges) over the study domain are summarized as follows. The annual mean surface concentration of BC is 0.88 μg/m3, ranging from 1 to 8 μg/m3 over North China and Central China. The all-sky and clear-sky radiative forcings of BC at the TOA are 0.43 and 0.39 W/m2, respectively. Over most parts of Southwest China, Central China, and North China, the BC warming effect prevails, with enhanced temperature of 0.04-0.28 K. BC aerosols usually enhance precipitation in South China and North China, ranging from 0.40 to 2.8 mm d- 1.

  20. Atmospheric black carbon deposition and characterization of biomass burning tracers in a northern temperate forest

    Science.gov (United States)

    Santos, F.; Fraser, M. P.; Bird, J. A.

    2014-10-01

    Aerosol black carbon (BC) is considered the second largest contributor to global warming after CO2, and is known to increase the atmosphere's temperature, decrease the albedo in snow/ice, and influence the properties and distribution of clouds. BC is thought to have a long mean residence time in soils, and its apparent stability may represent a significant stable sink for atmospheric CO2. Despite recent efforts to quantify BC in the environment, the quantification of BC deposition rates from the atmosphere to terrestrial ecosystems remains scarse. To better understand the contribution of atmospheric BC inputs to soils via dry deposition and its dominant emission sources, atmospheric fine particle (PM2.5) were collected at the University of Michigan Biological Station from July to September in 2010 and 2011. PM2.5 samples were analyzed for organic C, BC, and molecular markers including particulate sugars, carboxylic acids, n-alkanes, polycyclic aromatic hydrocarbons, and cholestane. Average atmospheric BC concentrations in northern Michigan were 0.048 ± 0.06 μg m-3 in summer 2010, and 0.049 ± 0.064 μg m-3 in summer 2011. Based on atmospheric concentrations, particulate deposition calculations, and documented soil BC, we conclude that atmospheric deposition is unlikely to comprise a significant input pathway for BC in northern forest ecosystem. The major organic tracers identified in fine particulates (e.g. levoglucosan and docosanoic acid) suggest that ambient PM2.5 concentrations were mainly influenced by biomass burning and epicuticular plant waxes. These results provide baseline data needed for future assessments of atmospheric BC in rural temperate forests.

  1. A Multi-Model Comparison of Black Carbon Budgets in the Arctic Region.

    Science.gov (United States)

    Mahmood, R.; von Salzen, K.; Flanner, M.; Sand, M.; Langner, J.; Wang, H.; Huang, L.

    2015-12-01

    In this study we quantify modeled aerosol processes related to black carbon (BC) concentrations in the Arctic region in several general circulation models used by the Expert Group on Arctic Monitoring and Assessment Program (AMAP). All models simulated well the observed seasonal cycle of BC concentrations in the high Canadian Arctic region, however, most models (except CanAM) underestimate the total concentrations. Transport of BC from lower latitudes is the major source for the Arctic region where emissions are small. The models produce similar seasonal cycle of BC transport towards the Arctic with maximum transport in July. However, substantial differences were found among the models in simulating BC burdens and vertical distributions with some models producing very week seasonal cycle while others producing stronger seasonality. The annual mean BC residence times in models also differs markedly with CanAM having the shortest residence times followed by SMHI-MATCH, CESM and NorESM. There are substantial differences among the models in simulating the relative role of wet and dry deposition rates which is one of the major factors causing variations in the seasonality of BC burdens in the models. Similarly, significant differences in wet deposition efficiencies among the models exist and are the leading cause of differences in simulated BC burdens. To further explore these processes, we performed several sensitivity tests in CanAM and CESM. Overall, the results indicate that scavenging of BC in convective clouds as compared to simulations without convective BC scavenging substantially increases the overall efficiency of BC wet deposition which leads to low BC burdens and a more pronounced seasonal cycle.

  2. Investigation on the direct radiative effect of fossil fuel black-carbon aerosol over China

    Science.gov (United States)

    Zhuang, Bingliang; Jiang, Fei; Wang, Tijian; Li, Shu; Zhu, Bin

    2011-06-01

    In China, due to lack of countrywide monitoring and coarse emission inventory of black carbon (BC) in early years, there are large uncertainties as to the estimations of its loading, direct radiative forcing (DRF) and climate response. Here, we apply an up-to-date emission inventory of BC in 2006 to investigate its loading, optical depth (AOD) at 550 nm and DRF using the coupled Regional Climate Chemistry Modeling System (RegCCMS). A state of the art air quality model (WRF/Chem) is also used to access surface BC concentration. Simulated surface concentrations of BC from these two models were compared with observations, while the AOD was compared with the results both from the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model and from satellite and ground-based simulations. Results show that RegCCMS presented similar patterns and levels of annual mean-surface BC concentration to those of WRF/Chem. The regional distributions and monthly variations of RegCCMS BC were reproduced well in comparison to observations. Simulated pattern of AODs are consistent to but lower than those from satellite (Omi-0.25°) and AERONET simulations. Annual mean DRFs mainly distribute in the area with high BC loadings, with regional mean of 0.75 W m-2 and predicted global mean of 0.343 W m-2. In general, the results are about 0.4-5 times for regional column burden, about 2 times as high for regional mean DRFs, about 1.3-1.8 times for global mean DRFs and about 3-4 times for AOD at 550 nm as compared to those in previous studies in China. These increasing DRFs of BC imply that its warming effect and climate response should be stronger and the DRF of total aerosols should be weaker (less negative).

  3. Black carbon aerosol over the Los Angeles Basin during CalNex

    Science.gov (United States)

    Metcalf, A. R.; Craven, J. S.; Ensberg, J. J.; Brioude, J.; Angevine, W.; Sorooshian, A.; Duong, H. T.; Jonsson, H. H.; Flagan, R. C.; Seinfeld, J. H.

    2012-04-01

    Refractory black carbon (rBC) mass and number concentrations were quantified by a Single Particle Soot Photometer (SP2) in the CalNex 2010 field study on board the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter in the Los Angeles (LA) Basin in May, 2010. The mass concentrations of rBC in the LA Basin ranged from 0.002-0.530μg m-3, with an average of 0.172 μg m-3. Lower concentrations were measured in the Basin outflow regions and above the inversion layer. The SP2 afforded a quantification of the mixing state of rBC aerosols through modeling the scattering cross-section with a core-and-shell Mie model to determine coating thickness. The rBC particles above the inversion layer were more thickly coated by a light-scattering substance than those below, indicating a more aged aerosol in the free troposphere. Near the surface, as the LA plume is advected from west to east with the sea breeze, a coating of scattering material grows on rBC particles, coincident with a clear growth of ammonium nitrate within the LA Basin and the persistence of water-soluble organic compounds as the plume travels through the outflow regions. Detailed analysis of the rBC mixing state reveals two modes of coated rBC particles; a mode with smaller rBC core diameters (˜90 nm) but thick (>200 nm) coating diameters and a mode with larger rBC cores (˜145 nm) with a thin (<75 nm) coating. The "weekend effect" in the LA Basin results in more thickly coated rBC particles, coinciding with more secondary formation of aerosol.

  4. Spatially and Temporally Refined Sources of Black Carbon Aerosols in the Arctic in spring

    Science.gov (United States)

    Qi, L.; Li, Q.; Mao, Y.; Chen, Y.; Randerson, J. T.; Wang, Q.; Hao, W. M.

    2014-12-01

    Black carbon (BC) aerosols play a substantial role in the rapid warming of the Arctic. We systematically evaluate the simulation of BC vertical profile (ARCTAS and ARCPAC flights), surface concentrations and concentrations in snow (Doherty et al., 2010) in the Arctic in spring using a global chemical transport model GEOS-Chem. We also provide highly spatially (2° lat ×2.5° lon) and temporally resolved source estimates of surface BC concentrations using GEOS-Chem adjoint. Results showed that the vertical profiles of BC agree with the aircraft observations from surface to 10 km within 50%. The monthly mean regional averaged BC concentrations in snow in Alaska, Arctic Ocean, Canada, Greenland and Russia agree with the observations within 40%, while the mean BC concentrations in snow in Svalbard and Norway agree with the observations within a factor of 3 because of inaccurate simulation of snow precipitation in GEOS5. We found Asian anthropogenic sources contributed 20-50% of BC concentrations through troposphere and in snow in the Arctic and are the major contributors in most regions. Adjoint analysis showed that BC concentrations of about 10 ng/m3 (30-100% of the total Asian contribution) observed at the surface stations are attributed to emissions emitted by Asian anthropogenic sources 30 days before the observation, and these background BC aerosols were transported to the station by circum-polar-vortex. Previous source estimates that repeated identified Europe as the major contributor of BC in the Arctic only trace back for 5 to 10 days and do not capture the background contribution from Asia. Russian biomass burning is important in mid-troposphere and accounts for 60% of total BC at 4-5 km. The relative contribution from different sources estimated by the adjoint of GEOS-Chem agrees with the forward estimate within 10%. Moreover, the adjoint analysis enables us to pinpoint the major sources to grid box level. Results showed that for surface observations

  5. Radiocarbon-based source apportionment of black carbon (BC) in PM 10 aerosols from residential area of suburban Tokyo

    Science.gov (United States)

    Uchida, Masao; Kumata, Hidetoshi; Koike, Yasuyo; Tsuzuki, Mikio; Uchida, Tatsuya; Fujiwara, Kitao; Shibata, Yasuyuki

    2010-04-01

    The AMS technique was applied to analyse black carbon (BC), total organic carbon (TOC), and previously reported polycyclic aromatic hydrocarbons (PAHs) in PM 10 aerosols from a residential area, suburban Tokyo, to determine natural abundance of radiocarbon ( 14C), an ideal tracer to distinguish fossil fuel ( 14C-free) from modern biomass combustion sources of pyrolytic products. The 14C concentrations in BC, isolated using the CTO-375 method, were 42% and 30% pMC (in terms of percent Modern Carbon: pMC) in summer and winter, respectively. The 14C concentrations in BC were also compared with those of compound-class specific 14C content of PAHs previously reported for the same samples: they were 45% and 33% pMC in summer and winter, respectively. The 14C signals of BC were identical to those of high molecular weight (MW ⩾ 226, 5-6 rings) PAHs. The resemblance between 14C signals of BC and PAHs can be referred as a 'certificate' for the validity of the BC isolation method employed in this study. Also, it suggests that 14C-BC approach can be a surrogate for PAHs specific 14C analyses to monitor seasonal source variation of combustion-derived pyrolytic products. On the other hand, 14C contents of total organic carbon in 2004 were 61% and 42% pMC in summer and winter, respectively. This is likely attributed to higher contribution of plant activity in summer.

  6. Changes in Fire-Derived Soil Black Carbon Storage in a Sub-humid Woodland

    Science.gov (United States)

    White, J. D.; Yao, J.; Murray, D. B.; Hockaday, W. C.

    2014-12-01

    Fire-derived black carbon (BC) in soil, including charcoal, represents a potentially important fraction of terrestrial carbon cycling due to its presumed long persistence in soil. Interpretation of site BC retention is important for assessing feedbacks to ecosystem processes including nutrient and water cycling. However, interaction between vegetation disturbance, BC formation, and off site transport may exist that complicate interpretation of BC addition to soils from wildfire or prescribed burns directly. To investigate the relationship between disturbance and site retention on soil BC, we determined BC concentrations for a woodland in central Texas, USA, from study plots in hilly terrain with a fire scar dendrochronology spanning 100 years. BC values were determined from 13C nuclear magnetic resonance (NMR) spectroscopy. Estimated values showed mean BC concentration of 2.73 ± 3.06 g BC kg-1 (0.91 ± 0.51 kg BC m-2) for sites with fire occurrence within the last 40 years compared with BC values of1.21 ± 1.70 g BC kg-1 soil (0.18 ± 0.14 kg BC m-2) for sites with fire 40 - 100 years ago. Sites with no tree ring evidence of fire during the last 100 years had the lowest mean soil BC concentration of 0.05 ± 0.11 g BC kg-1 (0.02 ± 0.03 kg BC m-2). Molecular proxies of stability (lignin/N) and decomposition (Alkyl C/O-Alky C) showed no differences across the sites, indicating that low potential for BC mineralization. Modeled soil erosion and time since fire from fire scar data showed that soil BC concentrations were inversely correlated. A modified the ecosystem process model, Biome-BGC, was also used simulate the effects of fire disturbance with different severities and seasonality on C cycling related to the BC production, effect on soil water availability, and off-site transport. Results showed that BC impacts on ecosystem processes, including net ecosystem exchange and leaf area development, were predominantly related to fire frequency. Site BC loss rates were

  7. Black carbon in seasonal snow across northern Xinjiang in northwestern China

    Science.gov (United States)

    Ye, Hao; Zhang, Rudong; Shi, Jinsen; Huang, Jianping; Warren, Stephen G.; Fu, Qiang

    2012-12-01

    Black carbon (BC) particles in snow can significantly reduce the snow albedo and enhance the absorption of solar radiation, with important impacts on climate and the hydrological cycle. A field campaign was carried out to measure the BC content in seasonal snow in Qinghai and Xinjiang provinces of western China, in January and February 2012. 284 snow samples were collected at 38 sites, 6 in Qinghai and 32 in Xinjiang. The observational results at the sites in Xinjiang, where the absorbing impurities in snow are dominated by BC particles, are reported in this work. The BC mass fractions in seasonal snow across northern Xinjiang have a median value of ˜70 ng g-1, much lower than those in northeast China. The estimated concentration of BC at the cleanest site in Xinjiang is 20 ng g-1, which is similar to that found along the coast of the Arctic Ocean. It is found that the BC content of snow decreases with altitude. Taking into account this altitude dependence, our measured BC contents in snow are consistent with a recent measurement of BC in winter snow on Tianshan glacier. The data from this field campaign should be useful for testing transport models and climate models for the simulated BC in snow.

  8. How useful is the mid-infrared spectroscopy in the assessment of black carbon in soils

    Directory of Open Access Journals (Sweden)

    J.M. de la Rosa

    2013-09-01

    Full Text Available Black carbon (BC, the recalcitrant continuum of products from incomplete combustion, includes char, charcoal and soot, being considered an important component of the global C cycle. However due to measurement uncertainties, the magnitude and distribution of BC is hardly known. In this study, a rapid and inexpensive spectroscopic technique, as it is mid-infrared spectroscopy in combination with oxidation procedures is proposed to quantify the recalcitrant aromatic fraction resistant, which can effectively determine the proportion of BC in soils. This method was tested by using a wide variety soil samples of various origin, composition and properties. Results were contrasted by those obtained by applying solid-state Nuclear Magnetic Resonance (NMR spectroscopy. Mid-infrared spectroscopy showed a very high predicting potential in the case of samples with large concentrations of BC by taking advantage of the relative optical density of the 2920 cm-1 C–H stretching band. In the case of soils with low BC contents, the application of Partial Least Square Regression to baseline-subtracted, second-derivative Fourier-Transformed Infra-red (FT-IR spectra lead to significant (P<0.05 cross-validation models. By this procedure a considerable improvement in forecasting the aromatic fraction resistant to the chemical oxidation steps (BC-like material was obtained.

  9. Optimized method for black carbon analysis in ice and snow using the Single Particle Soot Photometer

    Directory of Open Access Journals (Sweden)

    I. A. Wendl

    2014-03-01

    Full Text Available In this study we attempt to optimize the method for measuring black carbon (BC in snow and ice using a single particle soot photometer (SP2. Beside the previously applied ultrasonic (CETAC and Collison-type nebulizers we introduce a jet (APEX-Q nebulizer to aerosolize the aqueous sample for SP2 analysis. Both CETAC and APEX-Q require small sample volumes (few milliliters which makes them suitable for ice core analysis. The APEX-Q shows the least size-dependent nebulizing efficiency in the BC particle diameter range of 100–1000 nm. The CETAC has the advantage that air and liquid flows can be monitored continuously. All nebulizer-types require a calibration with BC standards for the determination of the BC mass concentration in unknown aqueous samples. We found Aquadag to be a suitable material for preparing calibration standards. Further, we studied the influence of different treatments for fresh discrete snow and ice samples as well as the effect of storage. The results show that samples are best kept frozen until analysis. Once melted, they should be sonicated for 25 min, immediately analyzed while being stirred and not be refrozen.

  10. Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection

    Science.gov (United States)

    Jones, Anthony C.; Haywood, James M.; Jones, Andy

    2016-03-01

    In this paper, we examine the potential climatic effects of geoengineering by sulfate, black carbon and titania injection against a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate scenarios in which the top-of-the-atmosphere radiative imbalance due to rising greenhouse gas concentrations is offset by sufficient aerosol injection throughout the 2020-2100 period. We find that the global-mean temperature is effectively maintained at historical levels for the entirety of the period for all three aerosol-injection scenarios, though there is a wide range of side-effects which are discussed in detail. The most prominent conclusion is that although the BC injection rate necessary to produce an equivalent global mean temperature response is much lower, the severity of stratospheric temperature changes (> +70 °C) and precipitation impacts effectively exclude BC from being a viable option for geoengineering. Additionally, while it has been suggested that titania would be an effective particle because of its high scattering efficiency, it also efficiently absorbs solar ultraviolet radiation producing a significant stratospheric warming (> +20 °C). As injection rates and climatic impacts for titania are close to those for sulfate, there appears to be little benefit in terms of climatic influence of using titania when compared to the injection of sulfur dioxide, which has the added benefit of being well-modeled through extensive research that has been carried out on naturally occurring explosive volcanic eruptions.

  11. A potential large and persistent black carbon forcing over Northern Pacific inferred from satellite observations

    Science.gov (United States)

    Li, Zhongshu; Liu, Junfeng; Mauzerall, Denise L.; Li, Xiaoyuan; Fan, Songmiao; Horowitz, Larry W.; He, Cenlin; Yi, Kan; Tao, Shu

    2017-01-01

    Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC’s climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R2 > 0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the mid-Pacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is seen over the Northern Pacific, with abundances varying consistently with the springtime Pacific/North American (PNA) index. Our sBC* dataset infers a widespread overestimation of BC loadings and BC Direct Radiative Forcing by current models over North Pacific, which further suggests that large uncertainties exist on aerosol-climate interactions over other remote oceanic areas beyond Pacific. PMID:28266532

  12. Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection

    Directory of Open Access Journals (Sweden)

    A. C. Jones

    2015-11-01

    Full Text Available In this paper, we examine the potential climatic effects of geoengineering by sulfate, black carbon and titania injection against a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate scenarios in which the top-of-the-atmosphere radiative imbalance due to rising greenhouse gas concentrations is offset by sufficient aerosol injection throughout the 2020–2100 period. We find that the global-mean temperature is effectively maintained at historical levels for the entirety of the period for all 3 aerosol-injection scenarios, though there are a wide range of side-effects which are discussed in detail. The most prominent conclusion is that although the BC injection rate necessary to produce an equivalent global mean temperature-response is much lower, the severity of stratospheric temperature changes (> +70 °C and precipitation impacts effectively exclude BC from being a viable option for geoengineering. Additionally, while it has been suggested that titania would be an effective particle because of its high scattering efficiency, it also efficiently absorbs solar ultraviolet radiation producing a significant stratospheric warming (> +20 °C. As injection rates for titania are close to those for sulfate, there appears little benefit of using titania when compared to injection of sulfur dioxide, which has the added benefit of being well modelled through extensive research that has been carried out on naturally occurring explosive volcanic eruptions.

  13. A characterization of Arctic aerosols on the basis of aerosol optical depth and black carbon measurements

    Directory of Open Access Journals (Sweden)

    R. S. Stone

    2014-06-01

    Full Text Available Abstract Aerosols, transported from distant source regions, influence the Arctic surface radiation budget. When deposited on snow and ice, carbonaceous particles can reduce the surface albedo, which accelerates melting, leading to a temperature-albedo feedback that amplifies Arctic warming. Black carbon (BC, in particular, has been implicated as a major warming agent at high latitudes. BC and co-emitted aerosols in the atmosphere, however, attenuate sunlight and radiatively cool the surface. Warming by soot deposition and cooling by atmospheric aerosols are referred to as “darkening” and “dimming” effects, respectively. In this study, climatologies of spectral aerosol optical depth AOD (2001–2011 and Equivalent BC (EBC (1989–2011 from three Arctic observatories and from a number of aircraft campaigns are used to characterize Arctic aerosols. Since the 1980s, concentrations of BC in the Arctic have decreased by more than 50% at ground stations where in situ observations are made. AOD has increased slightly during the past decade, with variations attributed to changing emission inventories and source strengths of natural aerosols, including biomass smoke and volcanic aerosol, further influenced by deposition rates and airflow patterns.

  14. A new algorithm for brown and black carbon identification and organic carbon detection in fine atmospheric aerosols by a multi-wavelength Aethalometer

    Directory of Open Access Journals (Sweden)

    F. Esposito

    2012-02-01

    Full Text Available A novel approach for the analysis of aerosol absorption coefficient measurements is presented. A 7-wavelenghts aethalometer has been employed to identify brown carbon (BrC and black carbon (BC and to detect organic carbon (OC in fine atmospheric aerosols (PM2.5. The Magee Aethalometer estimates the BC content in atmospheric particulate by measuring the light attenuation in the aerosols accumulated on a quartz filter, at the standard wavelength λ = 0.88 μm. The known Magee algorithm is based on the hypothesis of a mass absorption coefficient inversely proportional to the wavelength. The new algorithm has been developed and applied to the whole spectral range; it verifies the spectral absorption behavior and, thus, it distinguishes between black and brown carbon. Moreover, it allows also to correct the absorption estimation at the UV wavelength commonly used to qualitatively detect the presence of mixed hydrocarbons. The algorithm has been applied to data collected in Agri Valley, located in Southern Italy, where torched crude oil undergoes a pre-treatment process.

    The Magee Aethalometer has been set to measure Aerosol absorption coefficients τaer (λ, t every 5 min. Wavelength dependence of τaer (λ, t has been analyzed by a best-fit technique and, excluding UV-wavelengths, both the absorption Angstrom coefficient α and the BC (or BrC concentration have been determined. Finally, daily histograms of α provide information on optical properties of carbonaceous aerosol, while the extrapolation at UV-wavelengths gives information on the presence of semivolatile organic carbon (OC particles.

  15. Soil Organic Carbon, Black Carbon, and Enzyme Activity Under Long-Term Fertilization

    Institute of Scientific and Technical Information of China (English)

    SHAO Xing-hua; ZHENG Jian-wei

    2014-01-01

    The present study aims to understand the effects of long-term fertilization on soil organic carbon (SOC), black carbon (BC), enzyme activity, and the relationships among these parameters. Paddy ifeld was continuously fertilized over 30 yr with nine different fertilizer treatments including N, P, K, NP, NK, NPK, 2NPK (two-fold NPK), NPK+manure (NPKM), and CK (no fertilization), N, 90 kg urea-N ha-1 yr-1; P, 45 kg triple superphosphate-P2O5 ha-1 yr-1; K, 75 kg potassium chloride-K2O ha-1 yr-1;and pig manure, 22 500 kg ha-1 yr-1. Soil samples were collected and determined for SOC, BC content, and enzyme activity. The results showed that the SOC in the NPKM treatment was signiifcantly higher than those in the K, P, and CK treatments. The lowest SOC content was found in the CK treatment. SOC content was similar in the N, NP, NK, NPK, 2NPK, and NPKM treatments. There was no signiifcant difference in BC content among different treatments. The BC-to-SOC ratios (BC/SOC) ranged from 0.50 to 0.63, suggesting that BC might originate from the same source. Regarding enzyme activity, NPK treatment had higher urease activity than NPKM treatment. The urease activity of NPKM treatment was signiifcantly higher than that of 2NPK, NP, N, P, K, CK, and NPKM treatment which produced higher activities of acid phosphatase, catalase, and invertase than all other treatments. Our results indicated that long-term fertilization did not signiifcantly affect BC content. Concurrent application of manure and mineral fertilizers increased SOC content and signiifcantly enhanced soil enzyme activities. Correlation analysis showed that catalase activity was signiifcantly associated with invertase activity, but SOC, BC, and enzyme activity levels were not signiifcantly correlated with one another. No signiifcant correlations were observed between BC and soil enzymes. It is unknown whether soil enzymes play a role in the decomposition of BC.

  16. Hydrogen production using thermocatalytic decomposition of methane on Ni30/activated carbon and Ni30/carbon black.

    Science.gov (United States)

    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).

  17. Intercomparison of measurement techniques for black or elemental carbon under urban background conditions in wintertime: influence of biomass combustion.

    Science.gov (United States)

    Reisinger, P; Wonaschütz, A; Hitzenberger, R; Petzold, A; Bauer, H; Jankowski, N; Puxbaum, H; Chi, X; Maenhaut, W

    2008-02-01

    A generally accepted method to measure black carbon (BC) or elemental carbon (EC) still does not exist. An earlier study in the Vienna area comparing practically all measurement methods in use in Europe gave comparable BC and EC concentrations under summer conditions (Hitzenberger et al., 2006a). Under summer conditions, Diesel traffic is the major source for EC or BC in Vienna. Under winter conditions, space heating (also with biomass as fuel) is another important source (Caseiro et al., 2007). The present study compares the response of thermal methods (a modified Cachier method, Cachier et al., 1989; a thermal-optical method, Schmid et al., 2001; and two thermal-optical (TOT) methods using Sunset instruments, Birch and Cary, 1996 and Schauer et al., 2003) and optical methods (a light transmission method, Hansen et al., 1984; the integrating sphere method, Hitzenberger et al., 1996; and the multiangle absorption photometer MAAP, Petzold and Schönlinner, 2004). Significant differences were found between the TOT methods on the one hand and all other methods on the other. The TOT methods yielded EC concentrations that were lower by 44 and 17% than the average of all measured concentrations (including the TOT data). The largest discrepancy was found when the contribution of brown carbon (measured with the integrating sphere method) was largest.

  18. A dense Black Carbon network in the region of Paris, France: Implementation, objectives, and first results

    Science.gov (United States)

    Sciare, Jean; Petit, Jean-Eudes; Sarda-Esteve, Roland; Bonnaire, Nicolas; Gros, Valérie; Pernot, Pierre; Ghersi, Véronique; Ampe, Christophe; Songeur, Charlotte; Brugge, Benjamin; Debert, Christophe; Favez, Olivier; Le Priol, Tiphaine; Mocnik, Grisa

    2013-04-01

    Motivations. Road traffic and domestic wood burning emissions are two major contributors of particulate pollution in our cities. These two sources emit ultra-fine, soot containing, particles in the atmosphere, affecting health adversely, increasing morbidity and mortality from cardiovascular and respiratory conditions and casing lung cancer. A better characterization of soot containing aerosol sources in our major cities provides useful information for policy makers for assessment, implementation and monitoring of strategies to tackle air pollution issues affecting human health with additional benefits for climate change. Objectives. This study on local sources of primary Particulate Matter (PM) in the megacity of Paris is a follow-up of several programs (incl. EU-FP7-MEGAPOLI) that have shown that fine PM - in the Paris background atmosphere - is mostly secondary and imported. A network of 14 stations of Black Carbon has been implemented in the larger region of Paris to provide highly spatially resolved long term survey of local combustion aerosols. To our best knowledge, this is the first time that such densely BC network is operating over a large urban area, providing novel information on the spatial/temporal distribution of combustion aerosols within a post-industrialized megacity. Experimental. As part of the PRIMEQUAL "PREQUALIF" project, a dense Black Carbon network (of 14 stations) has been installed over the city of Paris beginning of 2012 in order to produce spatially resolved Equivalent Black Carbon (EBC) concentration maps with high time resolution through modeling and data assimilation. This network is composed of various real-time instruments (Multi-Angle Absorption Photometer, MAAP by THERMO; Multi-wavelength Aethalometers by MAGEE Scientific) implemented in contrasted sites (rural background, urban background, traffic) complementing the regulated measurements (PM, NOx) in the local air quality network AIRPARIF (http

  19. Seasonal trends in black carbon properties and co-pollutants in Mexico City

    Directory of Open Access Journals (Sweden)

    A. Retama

    2015-04-01

    Full Text Available The Mexico City Metropolitan Area (MCMA is a region that continues to grow in population and vehicular traffic as well as being the largest source of short lived climate pollutants (SLCP in Latin America. The local city government has made significant progress in controlling some of these pollutants, i.e. ozone (O3 and carbon monoxide (CO, but particulate matter (PM2.5 and PM10 and black carbon (BC have shown little response to mitigation strategies that have been in place for more than two decades. For the first time, extended measurements have been made of equivalent black carbon (eBC, derived from light absorption measurements made with a Photoacoustic Extinctiometer (PAX, over a 13 month period from March 2013 through March 2014. The daily trends in workday (Monday through Saturday and Sunday eBC, PM2.5 and the co-pollutants CO, O3 and NOx are evaluated with respect to the three primary seasons in that region: rainy, cold-dry and warm-dry. The maximum values in all of the particle and gas concentrations were significantly larger (Student's t test, P2.5, CO, O3, and NOx were 8.8 to 13.1 μg m-3 (40%, 49 to 73 μg m-3 (40%, 2.5 to 3.8 ppm (40%, 73 to 100 ppb (30% and 144 to 252 ppb (53%, respectively. The primary factors that lead to these large changes between the wet and dry seasons are the accelerated vertical mixing of boundary layer and free tropospheric air by the formation of clouds that dilutes the concentration of the SLCPs and the decreased actinic flux that reduces the production of ozone by photochemical reactions. A significant "weekend effect" was also identified, particularly the decrease in BC due to fewer large transport vehicles that are fueled by diesel that produces a large fraction of the BC emissions. The other co-pollutant concentrations are also significantly less on weekends except for O3 that shows no change in maximum values from workday to Sunday. As has been noted in previous studies, this lack of change is a

  20. Black Carbon Particle Number Distribution Measurements during the ATHENS-2013 Winter Campaign

    Science.gov (United States)

    Gkatzelis, Georgios; Papanastasiou, Dimitris; Florou, Kalliopi; Kaltsonoudis, Christos; Louvaris, Eyaggelos; Bezentakos, Spiridon; Biskos, Georgios; Pandis, Spuros

    2014-05-01

    Black Carbon (BC) particles emitted by anthropogenic sources play an important role both in climate change and in air quality degradation. Open burning in forests and savannas, combustion of diesel and solid fuels for cooking and heating in homes represent the majority of BC emissions. Earlier work has focused on the BC atmospheric direct radiative forcing that is mostly related to its mass concentration and optical properties of the corresponding particles. A variety of measurement techniques are used to measure the mass concentration of BC by taking advantage of its optical or physical properties. Moreover, the carbonaceous particles containing BC are also important for the indirect forcing of climate. This effect is mostly related to the number concentration of BC particles. The number distribution of BC particles especially below 100 nm is quite uncertain due to limitations of the existing measurement techniques. In this work we employed a thermodenuder-based method as an approach for the measurement of the BC number distribution. More specifically, we combined a thermodenuder (TD) operating at temperatures up to 300 ° C, with a Scanning Mobility Particle Sizer (SMPS) and a High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF AMS). Aerosol size and composition measurements were carried out both at ambient and at elevated TD temperatures in Athens field campaign during January and February of 2013. In parallel, a Multi-Angle Absorption Photometer (MAAP) provided information about the BC mass concentration while a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) measured the mixing state and the hygroscopicity of the particles as a function of their size. These measurements were then combined to estimate the number concentration of BC particles. Our analysis focused on different periods during the study. During some of them one source dominated the carbonaceous aerosol concentration. Such periods included rush hour traffic, nighttime wood

  1. Street characteristics and traffic factors determining road users' exposure to black carbon

    Energy Technology Data Exchange (ETDEWEB)

    Dons, Evi, E-mail: evi.dons@vito.be [VITO (Flemish Institute for Technological Research), Boeretang 200, 2400 Mol (Belgium); IMOB (Transportation Research Institute), Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Temmerman, Philip [IMOB (Transportation Research Institute), Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Van Poppel, Martine [VITO (Flemish Institute for Technological Research), Boeretang 200, 2400 Mol (Belgium); Bellemans, Tom; Wets, Geert [IMOB (Transportation Research Institute), Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Int Panis, Luc [VITO (Flemish Institute for Technological Research), Boeretang 200, 2400 Mol (Belgium); IMOB (Transportation Research Institute), Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium)

    2013-03-01

    Many studies nowadays make the effort of determining personal exposure rather than estimating exposure at the residential address only. While intra-urban air pollution can be modeled quite easily using interpolation methods, estimating exposure in transport is more challenging. The aim of this study is to investigate which factors determine black carbon (BC) concentrations in transport microenvironments. Therefore personal exposure measurements are carried out using portable aethalometers, trip diaries and GPS devices. More than 1500 trips, both by active modes and by motorized transport, are evaluated in Flanders, Belgium. GPS coordinates are assigned to road segments to allow BC concentrations to be linked with trip and road characteristics (trip duration, degree of urbanization, road type, traffic intensity, travel speed and road speed). Average BC concentrations on highways (10.7 μg/m{sup 3}) are comparable to concentrations on urban roads (9.6 μg/m{sup 3}), but levels are significantly higher than concentrations on rural roads (6.1 μg/m{sup 3}). Highways yield higher BC exposures for motorists compared to exposure on major roads and local roads. Overall BC concentrations are elevated at lower speeds (< 30 km/h) and at speeds above 80 km/h, in accordance to vehicle emission functions. Driving on roads with low traffic intensities resulted in lower exposures than driving on roads with higher traffic intensities (from 5.6 μg/m{sup 3} for roads with less than 500 veh/h, up to 12 μg/m{sup 3} for roads with over 2500 veh/h). Traffic intensity proved to be the major explanatory variable for in-vehicle BC exposure, together with timing of the trip and urbanization. For cyclists and pedestrians the range in BC exposure is smaller and models are less predictive; for active modes exposure seems to be influenced by timing and degree of urbanization only. - Highlights: ► Aethalometers, an electronic diary and GPS were used to measure exposure in transport ► More

  2. Natural variability in the surface ocean carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. S. Lovenduski

    2015-11-01

    Full Text Available We investigate variability in the surface ocean carbonate ion concentration ([CO32−] on the basis of a~long control simulation with an Earth System Model. The simulation is run with a prescribed, pre-industrial atmospheric CO2 concentration for 1000 years, permitting investigation of natural [CO32−] variability on interannual to multi-decadal timescales. We find high interannual variability in surface [CO32−] in the tropical Pacific and at the boundaries between the subtropical and subpolar gyres in the Northern Hemisphere, and relatively low interannual variability in the centers of the subtropical gyres and in the Southern Ocean. Statistical analysis of modeled [CO32−] variance and autocorrelation suggests that significant anthropogenic trends in the saturation state of aragonite (Ωaragonite are already or nearly detectable at the sustained, open-ocean time series sites, whereas several decades of observations are required to detect anthropogenic trends in Ωaragonite in the tropical Pacific, North Pacific, and North Atlantic. The detection timescale for anthropogenic trends in pH is shorter than that for Ωaragonite, due to smaller noise-to-signal ratios and lower autocorrelation in pH. In the tropical Pacific, the leading mode of surface [CO32−] variability is primarily driven by variations in the vertical advection of dissolved inorganic carbon (DIC in association with El Niño–Southern Oscillation. In the North Pacific, surface [CO32−] variability is caused by circulation-driven variations in surface DIC and strongly correlated with the Pacific Decadal Oscillation, with peak spectral power at 20–30-year periods. North Atlantic [CO32−] variability is also driven by variations in surface DIC, and exhibits weak correlations with both the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. As the scientific community seeks to detect the anthropogenic influence on ocean carbonate chemistry, these results

  3. Elevated Carbon Dioxide Concentration Reduces Alarm Signaling in Aphids.

    Science.gov (United States)

    Boullis, Antoine; Fassotte, Bérénice; Sarles, Landry; Lognay, Georges; Heuskin, Stéphanie; Vanderplanck, Maryse; Bartram, Stefan; Haubruge, Eric; Francis, Frédéric; Verheggen, François J

    2017-02-01

    Insects often rely on olfaction to communicate with conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations might impact pheromonal communication in insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid, Acyrthosiphon pisum, under ambient and elevated CO2 concentrations over several generations. We found that an increase in CO2 concentration reduced the production (i.e., individual content) and emission (released under predation events) of Eβf. While no difference in Eβf neuronal perception was observed, we found that an increase in CO2 strongly reduced the escape behavior expressed by an aphid colony following exposure to natural doses of alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases impact chemical communication in the pea aphid, and could potentially have a cascade effect on interactions with higher trophic levels.

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

    Science.gov (United States)

    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.

  5. Hydrogen and Carbon Black Production from the Degradation of Methane by Thermal Plasma

    Directory of Open Access Journals (Sweden)

    Leila Cottet

    2014-05-01

    Full Text Available Methane gas (CH4 is the main inducer of the so called greenhouse gases effect. Recent scientific research aims to minimize the accumulation of this gas in the atmosphere and to develop processes capable of producing stable materials with added value. Thermal plasma technology is a promising alternative to these applications, since it allows obtaining H2 and solid carbon from CH4, without the parallel formation of byproducts such as CO2 and NOx. In this work, CH4 was degraded by thermal plasma in order to produce hydrogen (H2 and carbon black. The degradation efficiency of CH4, selectivity for H2 production as well as the characterization of carbon black were studied. The best results were obtained in the CH4 flow rate of 5 L min-1 the degradation percentage and the selectivity for H2 production reached 98.8 % and 48.4 %, respectively. At flow rates of less than 5 L min-1 the selectivity for H2 production increases and reaches 91.9 %. The carbon black has obtained amorphous with hydrophobic characteristics and can be marketed to be used in composite material, and can also be activated chemically and/or physically and used as adsorbent material.

  6. Black carbon fractal morphology and short-wave radiative impact: a modelling study

    Directory of Open Access Journals (Sweden)

    M. Kahnert

    2011-08-01

    Full Text Available We investigate the impact of the morphological properties of freshly emitted black carbon aerosols on optical properties and on radiative forcing. To this end, we model the optical properties of fractal black carbon aggregates by use of numerically exact solutions to Maxwell's equations within a spectral range from the UVC to the mid-IR. The results are coupled to radiative transfer computations, in which we consider six realistic case studies representing different atmospheric pollution conditions and surface albedos. The spectrally integrated radiative impacts of black carbon are compared for two different fractal morphologies, which brace the range of recently reported experimental observations of black carbon fractal structures. We also gauge our results by performing corresponding calculations based on the homogeneous sphere approximation, which is commonly employed in climate models. We find that at top of atmosphere the aggregate models yield radiative impacts that can be as much as 2 times higher than those based on the homogeneous sphere approximation. An aggregate model with a low fractal dimension can predict a radiative impact that is higher than that obtained with a high fractal dimension by a factor ranging between 1.1–1.6. Although the lower end of this scale seems like a rather small effect, a closer analysis reveals that the single scattering optical properties of more compact and more lacy aggregates differ considerably. In radiative flux computations there can be a partial cancellation due to the opposing effects of differences in the optical cross sections and asymmetry parameters. However, this cancellation effect can strongly depend on atmospheric conditions and is therefore quite unpredictable. We conclude that the fractal morphology of black carbon aerosols and their fractal parameters can have a profound impact on their radiative forcing effect, and that the use of the homogeneous sphere model introduces unacceptably

  7. Abundance, distribution, and isotopic composition of particulate black carbon in the northern Gulf of Mexico

    Science.gov (United States)

    Yang, Weifeng; Guo, Laodong

    2014-11-01

    There exists increasing evidence supporting the important role of black carbon in global carbon cycles. Particulate black carbon (PBC) is allochthonous and has distinct reactivities compared to the bulk particulate organic carbon (tot-POC) in marine environments. However, the abundance, geochemical behavior of PBC and its importance in oceanic carbon budget remain poorly understood. Here we report the abundance, distribution, and stable isotopic signatures of BC derived from the chemo-thermal oxidation (CTO-375) method (BCCTO) in the Gulf of Mexico. Our results show that BCCTO abundance decreased from shelf to basin, and more than a half of riverine BCCTO could be removed over the shelf. Moreover, BCCTO is much more refractory compared to the tot-POC and has δ13C values lower than those of BC-excluded POC. These results highlight the significance of PBC in marine carbon cycles and potentially suggest the need for a new end-member term in quantifying POC sources in the ocean.

  8. An Investigation of the Effects of Black Carbon on Precipitation in the Western United States

    Science.gov (United States)

    Tseng, Hsien-Liang Rose

    Black carbon (BC), the byproduct of incomplete combustion, is considered to be the second most important anthropogenic climate forcing agent after carbon dioxide. BC warms the atmosphere by absorbing solar radiation (direct effect), alters cloud and precipitation formation by acting as cloud condensation nuclei (indirect effect), and modifies cloud distribution via cloud burn-off (semi-direct effect). Currently, there are large discrepancies in general circulation model estimates of the influence of BC on precipitation. Even less known is how BC changes precipitation on regional scales. In the drought-stricken western United States (WUS), where BC emissions are known to affect the hydrological cycle, an investigation on how BC influences precipitation is warranted. In this study, we employ the Weather Research and Forecasting-Chemistry (WRF Chem) model (version 3.6.0) with the newly chemistry- and microphysics-coupled Fu-Liou-Gu radiation scheme to study how black carbon affects precipitation by separating BC-related effects into direct and semi-direct, and indirect effects. In this three-part study, we use a recent wet year (2005) to investigate black carbon effects. We first examine BC effects during a heavy wintertime heavy precipitation event (7-11 January 2005), a heavy summertime precipitation week for comparison to the wintertime event (20-24 July 2005), and finally, examine these same effects for the months of January to June 2005 to investigate month-long trends. We find that BC suppresses precipitation, predominantly through its direct and semi-direct effects. The direct and semi-direct effects warm the air aloft, and cool the lower levels of the atmosphere (surface dimming) through the reduction of downward shortwave radiation flux at the surface. These changes in vertical temperature increase the stability of the atmosphere and reduce convective precipitation. Convective precipitation reduction accounts for approximately 60 75% of the total

  9. Seasonality of global and Arctic black carbon processes in the Arctic Monitoring and Assessment Programme models

    Science.gov (United States)

    Mahmood, Rashed; Salzen, Knut; Flanner, Mark; Sand, Maria; Langner, Joakim; Wang, Hailong; Huang, Lin

    2016-06-01

    This study quantifies black carbon (BC) processes in three global climate models and one chemistry transport model, with focus on the seasonality of BC transport, emissions, wet and dry deposition in the Arctic. In the models, transport of BC to the Arctic from lower latitudes is the major BC source for this region. Arctic emissions are very small. All models simulated a similar annual cycle of BC transport from lower latitudes to the Arctic, with maximum transport occurring in July. Substantial differences were found in simulated BC burdens and vertical distributions, with Canadian Atmospheric Global Climate Model (CanAM) (Norwegian Earth System Model, NorESM) producing the strongest (weakest) seasonal cycle. CanAM also has the shortest annual mean residence time for BC in the Arctic followed by Swedish Meteorological and Hydrological Institute Multiscale Atmospheric Transport and Chemistry model, Community Earth System Model, and NorESM. Overall, considerable differences in wet deposition efficiencies in the models exist and are a leading cause of differences in simulated BC burdens. Results from model sensitivity experiments indicate that convective scavenging outside the Arctic reduces the mean altitude of BC residing in the Arctic, making it more susceptible to scavenging by stratiform (layer) clouds in the Arctic. Consequently, scavenging of BC in convective clouds outside the Arctic acts to substantially increase the overall efficiency of BC wet deposition in the Arctic, which leads to low BC burdens and a more pronounced seasonal cycle compared to simulations without convective BC scavenging. In contrast, the simulated seasonality of BC concentrations in the upper troposphere is only weakly influenced by wet deposition in stratiform clouds, whereas lower tropospheric concentrations are highly sensitive.

  10. Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex

    Science.gov (United States)

    Ensberg, J. J.; Craven, J. S.; Metcalf, A. R.; Allan, J. D.; Angevine, W. M.; Bahreini, R.; Brioude, J.; Cai, C.; Coe, H.; Gouw, J. A.; Ellis, R. A.; Flynn, J. H.; Haman, C. L.; Hayes, P. L.; Jimenez, J. L.; Lefer, B. L.; Middlebrook, A. M.; Murphy, J. G.; Neuman, J. A.; Nowak, J. B.; Roberts, J. M.; Stutz, J.; Taylor, J. W.; Veres, P. R.; Walker, J. M.; Seinfeld, J. H.

    2013-02-01

    We evaluate predictions from the Community Multiscale Air Quality (CMAQ version 4.7.1) model against a suite of airborne and ground-based meteorological measurements, gas- and aerosol-phase inorganic measurements, and black carbon (BC) measurements over Southern California during the CalNex field campaign in May/June 2010. Ground-based measurements are from the CalNex Pasadena ground site, and airborne measurements took place onboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Navy Twin Otter and the NOAA WP-3D aircraft. BC predictions are in general agreement with observations at the Pasadena ground site and onboard the WP-3D, but are consistently overpredicted when compared to Twin Otter measurements. Adjustments to predicted inorganic mass concentrations, based on predicted aerosol size distributions and the AMS transmission efficiency, are shown to be significant. Owing to recent shipping emission reductions, the dominant source of sulfate in the L.A. Basin may now be long-range transport. Sensitivity studies suggest that severely underestimated ammonia emissions, and not the exclusion of crustal species (Ca2 +, K+, and Mg2 +), are the single largest contributor to measurement/model disagreement in the eastern part of the L.A. Basin. Despite overstated NOx emissions, total nitrate concentrations are underpredicted, which suggests a missing source of HNO3 and/or overprediction of deposition rates. Adding gas-phase NH3 measurements and size-resolved measurements, up to 10 μm, of nitrate and various cations (e.g. Na+, Ca2 +, K+) to routine monitoring stations in the L.A. Basin would greatly facilitate interpreting day-to-day fluctuations in fine and coarse inorganic aerosol.

  11. Black carbon aerosol characterization in a remote area of Qinghai-Tibetan Plateau, western China.

    Science.gov (United States)

    Wang, Qiyuan; Schwarz, J P; Cao, Junji; Gao, Rushan; Fahey, D W; Hu, Tafeng; Huang, R-J; Han, Yongming; Shen, Zhenxing

    2014-05-01

    The concentrations, size distributions, and mixing states of refractory black carbon (rBC) aerosols were measured with a ground-based Single Particle Soot Photometer (SP2), and aerosol absorption was measured with an Aethalometer at Qinghai Lake (QHL), a rural area in the Northeastern Tibetan Plateau of China in October 2011. The area was not pristine, with an average rBC mass concentration of 0.36 μg STP-m(-3) during the two-week campaign period. The rBC concentration peaked at night and reached the minimal in the afternoon. This diurnal cycle of concentration is negatively correlated with the mixed layer depth and ventilation. When air masses from the west of QHL were sampled in late afternoon to early evening, the average rBC concentration of 0.21 μg STP-m(-3) was observed, representing the rBC level in a larger Tibetan Plateau region because of the highest mixed layer depth. A lognormal primary mode with mass median diameter (MMD) of ~175 nm, and a small secondary lognormal mode with MMD of 470-500 nm of rBC were observed. Relative reduction in the secondary mode during a snow event supports recent work that suggested size dependent removal of rBC by precipitation. About 50% of the observed rBC cores were identified as thickly coated by non-BC material. A comparison of the Aethalometer and SP2 measurements suggests that non-BC species significantly affect the Aethalometer measurements in this region. A scaling factor for the Aethalometer data at a wavelength of 880 nm is therefore calculated based on the measurements, which may be used to correct other Aethalometer datasets collected in this region for a more accurate estimate of the rBC loading. The results present here significantly improve our understanding of the characteristics of rBC aerosol in the less studied Tibetan Plateau region and further highlight the size dependent removal of BC via precipitation.

  12. Effects of Nanoscale Carbon Black Modified by HNO3 on Immobilization and Phytoavailability of Ni in Contaminated Soil

    Directory of Open Access Journals (Sweden)

    Jiemin Cheng

    2015-01-01

    Full Text Available A surface-modified nanoscale carbon black (MCB as Ni adsorbent in contaminated soil was prepared by oxidizing the carbon black with 65% HNO3. The surface properties of the adsorbent were characterized by zeta potential analysis, scanning electron microscopy (SEM, and Fourier transform infrared spectroscopy (FTIRs. Batch experiments were conducted to evaluate the improvement of Ni2+ adsorption by MCB. Greenhouse cultivation experiments were conducted to examine the effect of MCB on the DTPA-extractable Ni2+ in soil, Ni2+ uptake of ryegrass shoot, and growth of ryegrass. Results indicated that MCB had much lower negative zeta potential, more functional groups for exchange and complexation of cation, and more heterogeneous pores and cavities for the adsorption of cation than the unmodified parent one (CB. MCB showed enhanced sorption capacity for Ni (qmax, 49.02 mg·g−1 compared with CB (qmax, 39.22 mg·g−1. Greenhouse cultivation experiment results showed that the biomass of ryegrass shoot and the Ni uptake of the ryegrass shoot were significantly increased and the concentrations of DTPA-extractable Ni in soil were significantly decreased with the increasing of MCB amount. It is clear from this work that the MCB had good adsorption properties for the Ni and could be applied in the in situ immobilization and remediation of heavy metal contaminated saline-alkali soils.

  13. Implications of multiple scattering on the assessment of black carbon aerosol radiative forcing

    Science.gov (United States)

    Nair, Vijayakumar S.; Suresh Babu, S.; Krishna Moorthy, K.; Satheesh, S. K.

    2014-11-01

    The effects of radiative coupling between scattering and absorbing aerosols, in an external mixture, on the aerosol radiative forcing (ARF) due to black carbon (BC), its sensitivity to the composite aerosol loading and composition, and surface reflectance are investigated using radiative transfer model simulations. The ARF due to BC is found to depend significantly on the optical properties of the ‘neighboring’ (non-BC) aerosol species. The scattering due to these species significantly increases the top of the atmospheric warming due to black carbon aerosols, and significant changes in the radiative forcing efficiency of BC. This is especially significant over dark surfaces (such as oceans), despite the ARF due to BC being higher over snow and land-surfaces. The spatial heterogeneity of this effect (coupling or multiple scattering by neighboring aerosol species) imposes large uncertainty in the estimation ARF due to BC aerosols, especially over the oceans.

  14. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black.

    Science.gov (United States)

    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.

  15. Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    YUAN Xia; FANG Kuan-jun

    2006-01-01

    Waterborne nanoscale carbon black dispersion (NCBD) was widely used in inkjet printing, spun-dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose (CMC) as dispersant.Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black (CB) particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it increased by ultrasonic with the increase of CMC viscosity. Ultrasonic is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size obviously decreased with increasing ultrasonic time and arrived at about 160 nm for 60 min. In addition, oxidation with 2 mol/L of H2O2 and 0.2 wt% of CMC300 reduced CB particle size to 160 nm at 90℃ for 2.5 h.

  16. Modulation of snow reflectance and snowmelt from Central Asian glaciers by anthropogenic black carbon

    Science.gov (United States)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel

    2017-01-01

    Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to snowmelt in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer snowmelt rate increases of up to 6.3% (7 cm a‑1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and snowmelt models.

  17. NANOMECHANICAL MAPPING OF CARBON BLACK REINFORCED NATURAL RUBBER BY ATOMIC FORCE MICROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Toshio Nishi; Hideyuki Nukaga; So Fujinami; Ken Nakajima

    2007-01-01

    Atomic force microscopy (AFM) has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young's modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young's modulus distribution image together with reconstructed real topographic image.Then we were able to recognize three regions; rubber matrix, carbon black (or bound rubber) and intermediate regions.Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space.

  18. Current Situation and Prospect of White Carbon Black Industry in China

    Institute of Scientific and Technical Information of China (English)

    Zhu Chunyu

    2011-01-01

    1.Analysis of Market Operation in 2010 Year 2010 is the ending year of the "11th Five-Year Plan".Under the effect of a series of central government policies including coping with the international financial crisis,accelerating the transformation of economic development pattern and economic restructuring,and promoting steady and rapid development of economy,the situation is basically established that industrial economy operation changes from turnaround to steady growth,and industrial economy develops steadily and rapidly.This can be shown in the white carbon black industry,through the whole year,white carbon black industry maintains steady and rapid development,and the output of which has grown greatly compared with last year.

  19. Human lung epithelial cell A549 proteome data after treatment with titanium dioxide and carbon black

    Directory of Open Access Journals (Sweden)

    Ngoc Q. Vuong

    2016-09-01

    Full Text Available 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 epi