WorldWideScience

Sample records for atmospheric emissions control

  1. Modeling study of natural emissions, source apportionment, and emission control of atmospheric mercury

    Science.gov (United States)

    Shetty, Suraj K.

    ) and CAMNet (Canadian Atmospheric Mercury Measurement Network). The model estimated a total deposition of 474 Mg yr-1 to the CONUS (Contiguous United States) domain, with two-thirds being dry deposited. Reactive gaseous mercury contributed the most to 60% of deposition. Emission speciation distribution is a key factor for local deposition as contribution from large point sources can be as high as 75% near (coal combustion processes has attracted great attention due to its toxicity and the emission-control regulations and has lead to advancement in state-of-the-art control technologies that alleviate the impact of mercury on ecosystem and human health. This part of the work applies a sorption model to simulate adsorption of mercury in flue gases, onto a confined-bed of activated carbon. The model's performances were studied at various flue gas flow rates, inlet mercury concentrations and adsorption bed temperatures. The process simulated a flue gas, with inlet mercury concentration of 300 ppb, entering at a velocity of 0.3 m s-1 from the bottom into a fixed bed (inside bed diameter of 1 m and 3 m bed height; bed temperature of 25 °C) of activated carbon (particle size of 0.004 m with density of 0.5 g cm-3 and surface area of 90.25 cm2 g -1). The model result demonstrated that a batch of activated carbon bed was capable of controlling mercury emission for approximately 275 days after which further mercury uptake starts to decrease till it reaches about 500 days when additional control ceases. An increase in bed temperature significantly reduces mercury sorption capacity of the activated carbon. Increase in flue gas flow rate may result in faster consumption of sorption capacity initially but at a later stage, the sorption rate decreases due to reduced sorption capacity. Thus, overall sorption rate remains unaffected. The activated carbon's effective life (time to reach saturation) is not affected by inlet mercury concentration, implying that the designing and operation

  2. Control of Atmospheric Emissions in the Wood Pulping Industry, Volume 3.

    Science.gov (United States)

    Hendrickson, E. R.; And Others

    Volume 3 contains chapters 9 through 13 of the final report on the control of atmospheric emissions in the wood pulping industry. These chapters deal with the following topics: sampling and analytical techniques; on-going research related to reduction of emissions; research and development recommendations; current industry investment and operating…

  3. Quantifying the effects of China's pollution control on atmospheric mercury emissions

    Science.gov (United States)

    Zhong, H.

    2014-12-01

    China has conducted series of air pollution control policies to reduce the pollutant emissions. Although not specifically for mercury (Hg), those policies are believed to have co-benefits on atmospheric Hg emission control. On the basis of field-tests data and updated information of energy conservation and emission control, we have developed multiple-year inventories of anthropogenic mercury emissions in China from 2005 to 2012. Three scenarios (scenario 0(S0), scenario 1(S1), scenario 2(S2)) with different emission controls and energy path are designed for prediction of the future Hg emissions for the country. In particular, comprehensive assessments has been conducted to evaluate the evolution of emission factors, recent emission trends, effects of control measures as well as the reliability of our results. The national total emissions of anthropogenic Hg are estimated to increase from 679.0 metric tons (t) in 2005 to 749.8 t in 2012, with the peak at 770.6 t in 2011. The annual growth rate of emissions can then be calculated at 2.1% during 2005-2011, much lower than that of energy consumption or economy of the country. Coal combustion, gold metallurgy and nonferrous metal smelting are the most significant Hg sources of anthropogenic origin, accounting together for 85% of national total emissions. Tightened air pollution controls in China should be important reasons for the smooth emission trends. Compared with 2005, 299 t Hg were reduced in 2010 from power plants, iron and steel smelting, nonferrous-smelting and cement production, benefiting from the improvement of control measures for those sectors. The speciation of Hg emissions is relatively stable for recent years, with the mass fractions of around 55%, 9% and 6% for Hg0, Hg2+ and Hgp respectively. Integrating the policy commitments on energy saving, different from the most conservative case S0, S2 shares the same energy path with S1, but includes more stringent emission control. Under those scenarios, we

  4. Effectiveness of Emission Controls to Reduce the Atmospheric Concentrations of Mercury.

    Science.gov (United States)

    Castro, Mark S; Sherwell, John

    2015-12-15

    Coal-fired power plants in the United States are required to reduce their emissions of mercury (Hg) into the atmosphere to lower the exposure of Hg to humans. The effectiveness of power-plant emission controls on the atmospheric concentrations of Hg in the United States is largely unknown because there are few long-term high-quality atmospheric Hg data sets. Here, we present the atmospheric concentrations of Hg and sulfur dioxide (SO2) measured from 2006 to 2015 at a relatively pristine location in western Maryland that is several (>50 km) kilometers downwind of power plants in Ohio, Pennsylvania, and West Virginia. Annual average atmospheric concentrations of gaseous oxidized mercury (GOM), SO2, fine particulate mercury (PBM2.5), and gaseous elemental mercury (GEM) declined by 75%, 75%, 43%, and 13%, respectively, and were strongly correlated with power-plant Hg emissions from the upwind states. These results provide compelling evidence that reductions in Hg emissions from power plants in the United States had their intended impact to reduce regional Hg pollution. PMID:26606506

  5. Model assessment of atmospheric pollution control schemes for critical emission regions

    Science.gov (United States)

    Zhai, Shixian; An, Xingqin; Liu, Zhao; Sun, Zhaobin; Hou, Qing

    2016-01-01

    In recent years, the atmospheric environment in portions of China has become significantly degraded and the need for emission controls has become urgent. Because more international events are being planned, it is important to implement air quality assurance targeted at significant events held over specific periods of time. This study sets Yanqihu (YQH), Beijing, the location of the 2014 Beijing APEC (Asia-Pacific Economic Cooperation) summit, as the target region. By using the atmospheric inversion model FLEXPART, we determined the sensitive source zones that had the greatest impact on the air quality of the YQH region in November 2012. We then used the air-quality model Models-3/CMAQ and a high-resolution emissions inventory of the Beijing-Tianjian-Hebei region to establish emission reduction tests for the entire source area and for specific sensitive source zones. This was achieved by initiating emission reduction schemes at different ratios and different times. The results showed that initiating a moderate reduction of emissions days prior to a potential event is more beneficial to the air quality of Beijing than initiating a high-strength reduction campaign on the day of the event. The sensitive source zone of Beijing (BJ-Sens) accounts for 54.2% of the total source area of Beijing (BJ), but its reduction effect reaches 89%-100% of the total area, with a reduction efficiency 1.6-1.9 times greater than that of the entire area. The sensitive source zone of Huabei (HuaB-Sens.) only represents 17.6% of the total area of Huabei (HuaB), but its emission reduction effect reaches 59%-97% of the entire area, with a reduction efficiency 4.2-5.5 times greater than that of the total area. The earlier that emission reduction measures are implemented, the greater the effect they have on preventing the transmission of pollutants. In addition, expanding the controlling areas to sensitive provinces and cities around Beijing (HuaB-sens) can significantly accelerate the reduction

  6. Role of sectoral and multi-pollutant emission control strategies in improving atmospheric visibility in the Yangtze River Delta, China

    International Nuclear Information System (INIS)

    The Community Multi-scale Air Quality modeling system is used to investigate the response of atmospheric visibility to the emission reduction from different sectors (i.e. industries, traffic and power plants) in the Yangtze River Delta, China. Visibility improvement from exclusive reduction of NOx or VOC emission was most inefficient. Sulfate and organic aerosol would rebound if NOx emission was exclusively reduced from any emission sector. The most efficient way to improve the atmospheric visibility was proven to be the multi-pollutant control strategies. Simultaneous emission reductions (20–50%) on NOx, VOC and PM from the industrial and mobile sectors could result in 0.3–1.0 km visibility improvement. And the emission controls on both NOx (85%) and SO2 (90%) from power plants gained the largest visibility improvement of up to 4.0 km among all the scenarios. The seasonal visibility improvement subject to emission controls was higher in summer while lower in the other seasons. -- Highlights: • Atmospheric visibility in the Yangtze River Delta is modeled and evaluated. • Responses of visibility changes to various emission reduction scenarios are compared. • Sulfate aerosol will increase if only NOx emission is reduced. • The multi-pollutant control strategy is most efficient for improving visibility. -- Responses of visibility changes to various emission reduction scenarios are compared. The multi-pollutant control strategy is most efficient for improving visibility in YRD, China

  7. Economic analysis of atmospheric mercury emission control for coal-fired power plants in China.

    Science.gov (United States)

    Ancora, Maria Pia; Zhang, Lei; Wang, Shuxiao; Schreifels, Jeremy; Hao, Jiming

    2015-07-01

    Coal combustion and mercury pollution are closely linked, and this relationship is particularly relevant in China, the world's largest coal consumer. This paper begins with a summary of recent China-specific studies on mercury removal by air pollution control technologies and then provides an economic analysis of mercury abatement from these emission control technologies at coal-fired power plants in China. This includes a cost-effectiveness analysis at the enterprise and sector level in China using 2010 as a baseline and projecting out to 2020 and 2030. Of the control technologies evaluated, the most cost-effective is a fabric filter installed upstream of the wet flue gas desulfurization system (FF+WFGD). Halogen injection (HI) is also a cost-effective mercury-specific control strategy, although it has not yet reached commercial maturity. The sector-level analysis shows that 193 tons of mercury was removed in 2010 in China's coal-fired power sector, with annualized mercury emission control costs of 2.7 billion Chinese Yuan. Under a projected 2030 Emission Control (EC) scenario with stringent mercury limits compared to Business As Usual (BAU) scenario, the increase of selective catalytic reduction systems (SCR) and the use of HI could contribute to 39 tons of mercury removal at a cost of 3.8 billion CNY. The economic analysis presented in this paper offers insights on air pollution control technologies and practices for enhancing atmospheric mercury control that can aid decision-making in policy design and private-sector investments. PMID:26141885

  8. Economic analysis of atmospheric mercury emission control for coal-fired power plants in China.

    Science.gov (United States)

    Ancora, Maria Pia; Zhang, Lei; Wang, Shuxiao; Schreifels, Jeremy; Hao, Jiming

    2015-07-01

    Coal combustion and mercury pollution are closely linked, and this relationship is particularly relevant in China, the world's largest coal consumer. This paper begins with a summary of recent China-specific studies on mercury removal by air pollution control technologies and then provides an economic analysis of mercury abatement from these emission control technologies at coal-fired power plants in China. This includes a cost-effectiveness analysis at the enterprise and sector level in China using 2010 as a baseline and projecting out to 2020 and 2030. Of the control technologies evaluated, the most cost-effective is a fabric filter installed upstream of the wet flue gas desulfurization system (FF+WFGD). Halogen injection (HI) is also a cost-effective mercury-specific control strategy, although it has not yet reached commercial maturity. The sector-level analysis shows that 193 tons of mercury was removed in 2010 in China's coal-fired power sector, with annualized mercury emission control costs of 2.7 billion Chinese Yuan. Under a projected 2030 Emission Control (EC) scenario with stringent mercury limits compared to Business As Usual (BAU) scenario, the increase of selective catalytic reduction systems (SCR) and the use of HI could contribute to 39 tons of mercury removal at a cost of 3.8 billion CNY. The economic analysis presented in this paper offers insights on air pollution control technologies and practices for enhancing atmospheric mercury control that can aid decision-making in policy design and private-sector investments.

  9. Control of atmospheric CO_2 concentrations by 2050: A calculation on the emission rights of different countries

    Institute of Scientific and Technical Information of China (English)

    DING ZhongLi; DUAN XiaoNan; GE QuanSheng; ZHANG ZhiQiang

    2009-01-01

    This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO_2 concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions re-ductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO_2 concentrations.That a system rooted in "cumulative emissions per capita," the best conception of the "common but differentiated responsibilities" principle affirmed by the Kyoto Protocol according to fundamental standards of fairness and justice, was demonstrated. Based on calculations of various countries' cu-mulative emissions per capita, estimates of their cumulative emissions from 1900 to 2005, and their annual emissions allowances into the future (2006-2050), a 470 ppmv atmospheric CO_2 concentration target was set. According to the following four objective indicators-total emissions allowance from 1900 to 2050, actual emissions from 1900 to 2005, emissions levels in 2005, and the average growth rate of emissions from 1996 to 2005-all countries and regions whose population was more than 300000 in 2005 were divided into four main groups: countries with emissions deficits, countries and regions needing to reduce their gross emissions, countries and regions needing to reduce their emissions growth rates, and countries that can maintain the current emissions growth rates. Based on this pro-posal, most G8 countries by 2005 had already expended their 2050 emissions allowances. The accu-mulated financial value based on emissions has reached more than 5.5 trillion US dollars (20 dollars per ton of CO_2). Even if these countries could achieve their ambitious emissions reduction targets in the future, their per capita emissions from 2006 to 2050 would still be much higher than those of de

  10. Control of atmospheric CO2 concentrations by 2050: A calculation on the emission rights of different countries

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO2 concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions reductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO2 concentrations. That a system rooted in "cumulative emissions per capita," the best conception of the "common but differentiated responsibilities" principle affirmed by the Kyoto Protocol according to fundamental standards of fairness and justice, was demonstrated. Based on calculations of various countries’ cumulative emissions per capita, estimates of their cumulative emissions from 1900 to 2005, and their annual emissions allowances into the future (2006―2050), a 470 ppmv atmospheric CO2 concentration target was set. According to the following four objective indicators―total emissions allowance from 1900 to 2050, actual emissions from 1900 to 2005, emissions levels in 2005, and the average growth rate of emissions from 1996 to 2005―all countries and regions whose population was more than 300000 in 2005 were divided into four main groups: countries with emissions deficits, countries and regions needing to reduce their gross emissions, countries and regions needing to reduce their emissions growth rates, and countries that can maintain the current emissions growth rates. Based on this proposal, most G8 countries by 2005 had already expended their 2050 emissions allowances. The accu-mulated financial value based on emissions has reached more than 5.5 trillion US dollars (20 dollars per ton of CO2). Even if these countries could achieve their ambitious emissions reduction targets in the future, their per capita emissions from 2006 to 2050 would still be much higher than those of

  11. Control technology for radioactive emissions to the atmosphere at US Department of Energy facilities

    International Nuclear Information System (INIS)

    The purpose of this report is to provide information to the US Environmental Protection agency (EPA) on existing technology for the control of radionuclide emissions into the air from US Department of Energy (DOE) facilities, and to provide EPA with information on possible additional control technologies that could be used to further reduce these emissions. Included in this report are generic discussions of emission control technologies for particulates, iodine, rare gases, and tritium. Also included are specific discussions of existing emission control technologies at 25 DOE facilities. Potential additional emission control technologies are discussed for 14 of these facilities. The facilities discussed were selected by EPA on the basis of preliminary radiation pathway analyses. 170 references, 131 figures, 104 tables

  12. Control technology for radioactive emissions to the atmosphere at US Department of Energy facilities

    Energy Technology Data Exchange (ETDEWEB)

    Moore, E.B.

    1984-10-01

    The purpose of this report is to provide information to the US Environmental Protection agency (EPA) on existing technology for the control of radionuclide emissions into the air from US Department of Energy (DOE) facilities, and to provide EPA with information on possible additional control technologies that could be used to further reduce these emissions. Included in this report are generic discussions of emission control technologies for particulates, iodine, rare gases, and tritium. Also included are specific discussions of existing emission control technologies at 25 DOE facilities. Potential additional emission control technologies are discussed for 14 of these facilities. The facilities discussed were selected by EPA on the basis of preliminary radiation pathway analyses. 170 references, 131 figures, 104 tables.

  13. Role of sectoral and multi-pollutant emission control strategies in improving atmospheric visibility in the Yangtze River Delta, China.

    Science.gov (United States)

    Huang, Kan; Fu, Joshua S; Gao, Yang; Dong, Xinyi; Zhuang, Guoshun; Lin, Yanfen

    2014-01-01

    The Community Multi-scale Air Quality modeling system is used to investigate the response of atmospheric visibility to the emission reduction from different sectors (i.e. industries, traffic and power plants) in the Yangtze River Delta, China. Visibility improvement from exclusive reduction of NOx or VOC emission was most inefficient. Sulfate and organic aerosol would rebound if NOx emission was exclusively reduced from any emission sector. The most efficient way to improve the atmospheric visibility was proven to be the multi-pollutant control strategies. Simultaneous emission reductions (20-50%) on NOx, VOC and PM from the industrial and mobile sectors could result in 0.3-1.0 km visibility improvement. And the emission controls on both NOx (85%) and SO2 (90%) from power plants gained the largest visibility improvement of up to 4.0 km among all the scenarios. The seasonal visibility improvement subject to emission controls was higher in summer while lower in the other seasons.

  14. Some questions of remote control of gas emissions to atmosphere by using differential optical absorption spectrometers

    International Nuclear Information System (INIS)

    Full Text: In the article the possibility for increasing of measurement accuracy of emissive gases arising during open waste burning on garbage dumps has been considered. For this purpose it is suggested to combine Differential Optical Absorption Spectrometers (DOAS) method with three wavelength method. It is shown, that such combination of two methods allows taking into account separately the influence of fine and coarse components of atmosphere aerosol on measurement results of investigated gases

  15. Evaluating the effects of China's pollution controls on inter-annual trends and uncertainties of atmospheric mercury emissions

    Science.gov (United States)

    Zhao, Y.; Zhong, H.; Zhang, J.; Nielsen, C. P.

    2015-04-01

    China's anthropogenic emissions of atmospheric mercury (Hg) are effectively constrained by national air pollution control and energy efficiency policies. In this study, improved methods, based on available data from domestic field measurements, are developed to quantify the benefits of Hg abatement by various emission control measures. Those measures include increased use of (1) flue gas desulfurization (FGD) and selective catalyst reduction (SCR) systems in power generation; (2) precalciner kilns with fabric filters (FF) in cement production; (3) mechanized coking ovens with electrostatic precipitators (ESP) in iron and steel production; and (4) advanced production technologies in nonferrous metal smelting. Investigation reveals declining trends in emission factors for each of these sources, which together drive a much slower growth of total Hg emissions than the growth of China's energy consumption and economy, from 679 metric tons (t) in 2005 to 750 t in 2012. In particular, estimated emissions from the above-mentioned four source types declined 3% from 2005 to 2012, which can be attributed to expanded deployment of technologies with higher energy efficiencies and air pollutant removal rates. Emissions from other anthropogenic sources are estimated to increase by 22% during the period. The species shares of total Hg emissions have been stable in recent years, with mass fractions of around 55, 39, and 6% for gaseous elemental Hg (Hg0), reactive gaseous mercury (Hg2+), and particle-bound mercury (Hgp), respectively. The higher estimate of total Hg emissions than previous inventories is supported by limited simulation of atmospheric chemistry and transport. With improved implementation of emission controls and energy saving, a 23% reduction in annual Hg emissions from 2012 to 2030, to below 600 t, is expected at the most. While growth in Hg emissions has been gradually constrained, uncertainties quantified by Monte Carlo simulation for recent years have increased

  16. Evaluating the effects of China's pollution control on inter-annual trends and uncertainties of atmospheric mercury emissions

    Science.gov (United States)

    Zhao, Y.; Zhong, H.; Zhang, J.; Nielsen, C. P.

    2014-10-01

    China's atmospheric mercury (Hg) emissions of anthropogenic origin have been effectively restrained through the national policy of air pollution control. Improved methods based on available field measurements are developed to quantify the benefits of Hg abatement through various emission control measures. Those measures include increased use of flue gas desulfurization (FGD) and selective catalyst reduction (SCR) systems for power sector, precalciners with fabric filter (FF) for cement production, machinery coking with electrostatic precipitator (ESP) for iron and steel production, and advanced manufacturing technologies for nonferrous metal smelting. Declining trends in emissions factors for those sources are revealed, leading to a much slower growth of national total Hg emissions than that of energy and economy, from 679 in 2005 to 750 metric tons (t) in 2012. In particular, nearly half of emissions from the above-mentioned four types of sources are expected to be reduced in 2012, attributed to expansion of technologies with high energy efficiencies and air pollutant removal rates after 2005. The speciation of Hg emissions keeps stable for recent years, with the mass fractions of around 55, 39 and 6% for Hg0, Hg2+ and Hgp, respectively. The lower estimate of Hg emissions than previous inventories is supported by limited chemistry simulation work, but middle-to-long term observation on ambient Hg levels is further needed to justify the inter-annual trends of estimated Hg emissions. With improved implementation of emission controls and energy saving, 23% reduction in annual Hg emissions for the most optimistic case in 2030 is expected compared to 2012, with total emissions below 600 t. While Hg emissions are evaluated to be gradually constrained, increased uncertainties are quantified with Monte-Carlo simulation for recent years, particularly for power and certain industrial sources. The uncertainty of Hg emissions from coal-fired power plants, as an example

  17. Evaluating the effects of China's pollution control on inter-annual trends and uncertainties of atmospheric mercury emissions

    Directory of Open Access Journals (Sweden)

    Y. Zhao

    2014-10-01

    Full Text Available China's atmospheric mercury (Hg emissions of anthropogenic origin have been effectively restrained through the national policy of air pollution control. Improved methods based on available field measurements are developed to quantify the benefits of Hg abatement through various emission control measures. Those measures include increased use of flue gas desulfurization (FGD and selective catalyst reduction (SCR systems for power sector, precalciners with fabric filter (FF for cement production, machinery coking with electrostatic precipitator (ESP for iron and steel production, and advanced manufacturing technologies for nonferrous metal smelting. Declining trends in emissions factors for those sources are revealed, leading to a much slower growth of national total Hg emissions than that of energy and economy, from 679 in 2005 to 750 metric tons (t in 2012. In particular, nearly half of emissions from the above-mentioned four types of sources are expected to be reduced in 2012, attributed to expansion of technologies with high energy efficiencies and air pollutant removal rates after 2005. The speciation of Hg emissions keeps stable for recent years, with the mass fractions of around 55, 39 and 6% for Hg0, Hg2+ and Hgp, respectively. The lower estimate of Hg emissions than previous inventories is supported by limited chemistry simulation work, but middle-to-long term observation on ambient Hg levels is further needed to justify the inter-annual trends of estimated Hg emissions. With improved implementation of emission controls and energy saving, 23% reduction in annual Hg emissions for the most optimistic case in 2030 is expected compared to 2012, with total emissions below 600 t. While Hg emissions are evaluated to be gradually constrained, increased uncertainties are quantified with Monte-Carlo simulation for recent years, particularly for power and certain industrial sources. The uncertainty of Hg emissions from coal-fired power plants, as an

  18. Contribution of emission control and atmospheric diffusion ability to the improved air quality in 2015 of China

    Science.gov (United States)

    Wang, X.; Wang, K.

    2015-12-01

    China experiences extremely severe and frequent PM2.5 (fine particulate matters with diameters less than 2.5 µm) pollution in recent years, arousing unprecedented public concern. Tough targets have been set for three particularly smog-ridden regions: JingJinJi area, the Yangtze River Delta and Pearl River Delta, requiring these regions to reduce their atmospheric levels of PM2.5 by 25%, 20% and 15% respectively by the year 2017. A lot of mitigation actions have been taken to improve the air quality in China. In January 2013, China began to deploy instruments to measure PM2.5 nationally and released hourly observational data to the public. Observed PM2.5 concentrations showed a significant decrease in 2015 comparing to that of 2014 as shown in Fig.1. Many studies have attributed this kind of air quality improvement to the effect of emission control. However, air quality not only depends on the original emission, the atmospheric abilities of contaminant transfer, spread and wet deposition play a big role in reducing the ambient air pollutants and directly determined by the occurrence of pollution episodes. Here we used the first 2 years PM2.5 observation data in China to quantify the contribution of the effect of emission control and atmospheric ability of diffusing on reducing ambient PM2.5 concentrations. We found that PM2.5 decreased by 24% in 2015 winter (Dec. 2014-Feb. 2015) comparing to that in 2014; and 12% of decrease occurred for the spring time. The inconsistent seasonal improvement of air quality is mainly due to the favorable atmospheric background in 2015, with its frequent precipitation, infrequency of surface calm wind during the wintertime.

  19. The effects of recent control policies on trends in emissions of anthropogenic atmospheric pollutants and CO2 in China

    Directory of Open Access Journals (Sweden)

    C. P. Nielsen

    2013-01-01

    Full Text Available To examine the effects of China's national policies of energy conservation and emission control during 2005–2010, inter-annual emission trends of gaseous pollutants, primary aerosols, and CO2 are estimated with a bottom-up framework. The control measures led to improved energy efficiency and/or increased penetration of emission control devices at power plants and other important industrial sources, yielding reduced emission factors for all evaluated species except NOx. The national emissions of anthropogenic SO2, CO, and total primary PM (particulate matter in 2010 are estimated to have been 89%, 108%, and 87% of those in 2005, respectively, suggesting successful emission control of those species despite fast growth of the economy and energy consumption during the period. The emissions of NOx and CO2, however, are estimated to have increased by 47% and 43%, respectively, indicating that they remain largely determined by the growth of energy use, industrial production, and vehicle populations. Based on application of a Monte-Carlo framework, estimated uncertainties of SO2 and PM emissions increased from 2005 to 2010, resulting mainly from poorly understood average SO2 removal efficiency in flue gas desulfurization (FGD systems in the power sector, and unclear changes in the penetration levels of dust collectors at industrial sources, respectively. While emission trends determined by bottom-up methods can be generally verified by observations from both ground stations and satellites, clear discrepancies exist for given regions and seasons, indicating a need for more accurate spatial and time distributions of emissions. Limitations of current emission control polices are analyzed based on the estimated emission trends. Compared with control of total PM, there are fewer gains in control of fine particles and carbonaceous aerosols, the PM components most responsible for damages to public health and effects on radiative forcing. A much faster

  20. The effects of recent control policies on trends in emissions of anthropogenic atmospheric pollutants and CO2 in China

    Directory of Open Access Journals (Sweden)

    C. P. Nielsen

    2012-09-01

    Full Text Available To examine the effects of China's national policies of energy conservation and emission control during 2005–2010, inter-annual emission trends of gaseous pollutants, primary aerosols, and CO2 are estimated with a bottom-up framework. The control measures led to improved energy efficiency and/or increased penetration of emission control devices at power plants and other important industrial sources, yielding reduced emission factors for all evaluated species except NOx. The national emissions of anthropogenic SO2, CO, and total primary PM (particulate matter in 2010 are estimated to have been 89%, 108%, and 86% of those in 2005, respectively, suggesting successful emission control of those species despite fast growth of the economy and energy consumption during the period. The emissions of NOx and CO2, however, are estimated to have increased by 48% and 43%, respectively, indicating that they remain largely determined by the growth of energy use, industrial production, and vehicle populations. Based on application of a Monte-Carlo framework, estimated uncertainties of SO2 and PM emissions increased from 2005 to 2010, resulting mainly from weakly understood average SO2 removal efficiency in flue gas desulfurization (FGD systems in the power sector, and unclear changes in the penetration levels of dust collectors at industrial sources, respectively. While emission trends determined by bottom-up methods can be generally verified by observations from both ground stations and satellites, clear discrepancies exist for given regions and seasons, indicating a need for more accurate spatial and time distributions of emissions. Limitations of current emission control polices are analyzed based on the estimated emission trends. Compared with control of total PM, there are fewer gains in control of fine particles and carbonaceous aerosols, the PM forms most responsible for damages to public health and effects on radiative forcing. A decrease of alkaline

  1. The effects of recent control policies on trends in emissions of anthropogenic atmospheric pollutants and CO2 in China

    Science.gov (United States)

    Zhao, Y.; Zhang, J.; Nielsen, C. P.

    2013-01-01

    To examine the effects of China's national policies of energy conservation and emission control during 2005-2010, inter-annual emission trends of gaseous pollutants, primary aerosols, and CO2 are estimated with a bottom-up framework. The control measures led to improved energy efficiency and/or increased penetration of emission control devices at power plants and other important industrial sources, yielding reduced emission factors for all evaluated species except NOx. The national emissions of anthropogenic SO2, CO, and total primary PM (particulate matter) in 2010 are estimated to have been 89%, 108%, and 87% of those in 2005, respectively, suggesting successful emission control of those species despite fast growth of the economy and energy consumption during the period. The emissions of NOx and CO2, however, are estimated to have increased by 47% and 43%, respectively, indicating that they remain largely determined by the growth of energy use, industrial production, and vehicle populations. Based on application of a Monte-Carlo framework, estimated uncertainties of SO2 and PM emissions increased from 2005 to 2010, resulting mainly from poorly understood average SO2 removal efficiency in flue gas desulfurization (FGD) systems in the power sector, and unclear changes in the penetration levels of dust collectors at industrial sources, respectively. While emission trends determined by bottom-up methods can be generally verified by observations from both ground stations and satellites, clear discrepancies exist for given regions and seasons, indicating a need for more accurate spatial and time distributions of emissions. Limitations of current emission control polices are analyzed based on the estimated emission trends. Compared with control of total PM, there are fewer gains in control of fine particles and carbonaceous aerosols, the PM components most responsible for damages to public health and effects on radiative forcing. A much faster decrease of alkaline base

  2. Atmospheric process evaluation of mobile source emissions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

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

  3. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    Science.gov (United States)

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  4. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    Science.gov (United States)

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  5. Smokestack emission control apparatus

    International Nuclear Information System (INIS)

    A smokestack emissions control device is mounted to a smokestack, or the like, to clean and cool the emissions from the stack. The apparatus includes a housing shaped to be mounted on top of an emission stack and has a liquid tank formed in the housing for supporting a liquid therein. The tank is mounted directly in the passageway of escaping emissions to force the emissions through the liquid. A tank baffle extends into the liquid tank and into a liquid therein to force the escaping emissions from the smokestack through the liquid. A reduced pressure chamber is located adjacent to the liquid tank to create a negative pressure on one side of the liquid in the tank to draw the smokestack emissions through the liquid. A separator is located near the base of the stack wit pipes connecting the separator to the liquid bath for circulating the liquid in the liquid tank. the liquid in the bath can be specially formulated for the particular emissions from the emission stack. Anti-foaming and bubbling means are included to prevent the liquid from forming out of the tank. The tank is lightweight and allows the entire apparatus to be placed on an existing exhaust stack

  6. Inventory of U.S. 2012 dioxin emissions to atmosphere.

    Science.gov (United States)

    Dwyer, Henri; Themelis, Nickolas J

    2015-12-01

    In 2006, the U.S. EPA published an inventory of dioxin emissions for the U.S. covering the period from 1987-2000. This paper is an updated inventory of all U.S. dioxin emissions to the atmosphere in the year 2012. The sources of emissions of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), collectively referred to in this paper as "dioxins", were separated into two classes: controlled industrial and open burning sources. Controlled source emissions decreased 95.5% from 14.0 kg TEQ in 1987 to 0.6 kg in 2012. Open burning source emissions increased from 2.3 kg TEQ in 1987 to 2.9 kg in 2012. The 2012 dioxin emissions from 53 U.S. waste-to-energy (WTE) power plants were compiled on the basis of detailed data obtained from the two major U.S. WTE companies, representing 84% of the total MSW combusted (27.4 million metric tons). The dioxin emissions of all U.S. WTE plants in 2012 were 3.4 g TEQ and represented 0.54% of the controlled industrial dioxin emissions, and 0.09% of all dioxin emissions from controlled and open burning sources. PMID:26297638

  7. Controlling spontaneous emission

    DEFF Research Database (Denmark)

    Lodahl, Peter

    dots (QDs) embedded in 3D photonic crystals consisting of air spheres in titanium dioxide. Performing time-resolved experiments, we show that the photonic crystals control the emission decay rate of excitons confined in the QDs1,2. By varying the lattice parameter of the photonic crystals, we...

  8. Automotive Emission Control.

    Science.gov (United States)

    Lee, Billy D.; Ragazzi, Ronald

    This guide designed to assist teachers in improving instruction in the area of automotive emission control curriculum includes four areas. Each area consists of one or more units of instruction, with each instructional unit including some or all of the following basic components: Performance objectives, suggested activities for teacher and…

  9. Constraining CO emission estimates using atmospheric observations

    Science.gov (United States)

    Hooghiemstra, P. B.

    2012-06-01

    We apply a four-dimensional variational (4D-Var) data assimilation system to optimize carbon monoxide (CO) emissions and to reduce the uncertainty of emission estimates from individual sources using the chemistry transport model TM5. In the first study only a limited amount of surface network observations from the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) is used to test the 4D-Var system. Uncertainty reduction up to 60% in yearly emissions is observed over well-constrained regions and the inferred emissions compare well with recent studies for 2004. However, since the observations only constrain total CO emissions, the 4D-Var system has difficulties separating anthropogenic and biogenic sources in particular. The inferred emissions are validated with NOAA aircraft data over North America and the agreement is significantly improved from the prior to posterior simulation. Validation with the Measurements Of Pollution In The Troposphere (MOPITT) instrument shows a slight improved agreement over the well-constrained Northern Hemisphere and in the tropics (except for the African continent). However, the model simulation with posterior emissions underestimates MOPITT CO total columns on the remote Southern Hemisphere (SH) by about 10%. This is caused by a reduction in SH CO sources mainly due to surface stations on the high southern latitudes. In the second study, we compare two global inversions to estimate carbon monoxide (CO) emissions for 2004. Either surface flask observations from NOAA or CO total columns from the MOPITT instrument are assimilated in a 4D-Var framework. In the Southern Hemisphere (SH) three important findings are reported. First, due to their different vertical sensitivity, the stations-only inversion increases SH biomass burning emissions by 108 Tg CO/yr more than the MOPITT-only inversion. Conversely, the MOPITT-only inversion results in SH natural emissions

  10. Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial distribution, uncertainties, and control policies

    Science.gov (United States)

    Tian, H. Z.; Zhu, C. Y.; Gao, J. J.; Cheng, K.; Hao, J. M.; Wang, K.; Hua, S. B.; Wang, Y.; Zhou, J. R.

    2015-09-01

    Anthropogenic atmospheric emissions of typical toxic heavy metals have caused worldwide concern due to their adverse effects on human health and the ecosystem. By determining the best available representation of time-varying emission factors with S-shape curves, we establish the multiyear comprehensive atmospheric emission inventories of 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn) from primary anthropogenic activities in China for the period of 1949-2012 for the first time. Further, we allocate the annual emissions of these heavy metals in 2010 at a high spatial resolution of 0.5° × 0.5° grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). Our results show that the historical emissions of Hg, As, Se, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn, during the period of 1949-2012, increased by about 22-128 times at an annual average growth rate of 5.1-8.0 %, reaching about 526.9-22 319.6 t in 2012. Nonferrous metal smelting, coal combustion of industrial boilers, brake and tyre wear, and ferrous metal smelting represent the dominant sources of heavy metal emissions. In terms of spatial variation, the majority of emissions are concentrated in relatively developed regions, especially for the northern, eastern, and southern coastal regions. In addition, because of the flourishing nonferrous metal smelting industry, several southwestern and central-southern provinces play a prominent role in some specific toxic heavy metals emissions, like Hg in Guizhou and As in Yunnan. Finally, integrated countermeasures are proposed to minimize the final toxic heavy metals discharge on account of the current and future demand of energy-saving and pollution reduction in China.

  11. Atmospheric benzenoid emissions from plants rival those from fossil fuels.

    Science.gov (United States)

    Misztal, P K; Hewitt, C N; Wildt, J; Blande, J D; Eller, A S D; Fares, S; Gentner, D R; Gilman, J B; Graus, M; Greenberg, J; Guenther, A B; Hansel, A; Harley, P; Huang, M; Jardine, K; Karl, T; Kaser, L; Keutsch, F N; Kiendler-Scharr, A; Kleist, E; Lerner, B M; Li, T; Mak, J; Nölscher, A C; Schnitzhofer, R; Sinha, V; Thornton, B; Warneke, C; Wegener, F; Werner, C; Williams, J; Worton, D R; Yassaa, N; Goldstein, A H

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y(-1)), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  12. Atmospheric emissions control at ENELVEN`s Ramon Laguna thermal power plant; Control de emisiones a la atmosfera en la central termoelectrica Ramon Laguna de ENELVEN

    Energy Technology Data Exchange (ETDEWEB)

    Rincon Rincon, Edis Rafael [Empresa de Servicio Electrico (ENELVEN), (Venezuela)

    1996-12-31

    ENELVEN is an electric utility that covers the areas of generation, transmission and distribution of the Western an South coast of the Maracaibo Lake of the Zulia State, Venezuela. General aspects of the Ramon Laguna of ENELVEN fossil power plant are presented, as well as the environmental measures implanted in this power station to avoid detrimental effects on the environment that could be caused by the emission of combustion products without the appropriate control, such as particulate matter, sulfur oxides, nitrogen oxides and carbon oxides [Espanol] ENELVEN es una empresa de servicio electrico que cubre las areas de generacion, transmision y distribucion de la Costa Occidental y Sur del Lago de Maracaibo, del Estado Zulia, Venezuela. Se presentan aspectos generales de la planta termoelectrica Ramon Laguna de la empresa ENELVEN, asi como las medidas ambientales implantadas en esta central para evitar efectos adversos sobre el ambiente que pudieran producirse por la emision de productos de la combustion si no existiera el debido control, tales como: particulas, oxidos de azufre, oxidos de nitrogeno y oxidos de carbono

  13. Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial variation distribution, uncertainties and control policies

    Directory of Open Access Journals (Sweden)

    H. Z. Tian

    2015-04-01

    Full Text Available Anthropogenic atmospheric emissions of typical toxic heavy metals have received worldwide concerns due to their adverse effects on human health and the ecosystem. By determining the best available representation of time-varying emission factors with S-shape curves, we established the multiyear comprehensive atmospheric emission inventories of 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn from primary anthropogenic activities in China for the period of 1949–2012 for the first time. Further, we allocated the annual emissions of these heavy metals in 2010 at a high spatial resolution of 0.5° × 0.5° grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP. Our results show that the historical emissions of Hg, As, Se, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn during the period of 1949–2012, have been increased by about 22–128 times at an annual average growth rate of 5.1–8.0%, amounting to about 79 570 t in 2012. Nonferrous metal smelting, coal combustion of industrial boilers, brake and tyre wear, and ferrous metals smelting represent the dominant sources for Hg / Cd, As / Se / Pb / Cr / Ni / Mn / Co, Sb / Cu, and Zn, respectively. In terms of spatial variation, the majority of emissions were concentrated in relatively developed regions, especially for the northern, eastern and southern coastal regions. In addition, because of the flourishing nonferrous metals smelting industry, several southwestern and central-southern provinces play a prominent role in some specific toxic heavy metals emissions, like Hg in Guizhou and As in Yunnan. Finally, integrated countermeasures are proposed to minimize the final toxic heavy metals discharge on accounting of the current and future demand of energy-saving and pollution reduction in China.

  14. Quantitative assessment of atmospheric emissions of toxic heavy metals from anthropogenic sources in China: historical trend, spatial variation distribution, uncertainties and control policies

    Science.gov (United States)

    Tian, H. Z.; Zhu, C. Y.; Gao, J. J.; Cheng, K.; Hao, J. M.; Wang, K.; Hua, S. B.; Wang, Y.; Zhou, J. R.

    2015-04-01

    Anthropogenic atmospheric emissions of typical toxic heavy metals have received worldwide concerns due to their adverse effects on human health and the ecosystem. By determining the best available representation of time-varying emission factors with S-shape curves, we established the multiyear comprehensive atmospheric emission inventories of 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn) from primary anthropogenic activities in China for the period of 1949-2012 for the first time. Further, we allocated the annual emissions of these heavy metals in 2010 at a high spatial resolution of 0.5° × 0.5° grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). Our results show that the historical emissions of Hg, As, Se, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn during the period of 1949-2012, have been increased by about 22-128 times at an annual average growth rate of 5.1-8.0%, amounting to about 79 570 t in 2012. Nonferrous metal smelting, coal combustion of industrial boilers, brake and tyre wear, and ferrous metals smelting represent the dominant sources for Hg / Cd, As / Se / Pb / Cr / Ni / Mn / Co, Sb / Cu, and Zn, respectively. In terms of spatial variation, the majority of emissions were concentrated in relatively developed regions, especially for the northern, eastern and southern coastal regions. In addition, because of the flourishing nonferrous metals smelting industry, several southwestern and central-southern provinces play a prominent role in some specific toxic heavy metals emissions, like Hg in Guizhou and As in Yunnan. Finally, integrated countermeasures are proposed to minimize the final toxic heavy metals discharge on accounting of the current and future demand of energy-saving and pollution reduction in China.

  15. Coal fired flue gas mercury emission controls

    CERN Document Server

    Wu, Jiang; Pan, Weiguo; Pan, Weiping

    2015-01-01

    Mercury (Hg) is one of the most toxic heavy metals, harmful to both the environment and human health. Hg is released into the atmosphere from natural and anthropogenic sources and its emission control has caused much concern. This book introduces readers to Hg pollution from natural and anthropogenic sources and systematically describes coal-fired flue gas mercury emission control in industry, especially from coal-fired power stations. Mercury emission control theory and experimental research are demonstrated, including how elemental mercury is oxidized into oxidized mercury and the effect of

  16. Atmospheric emission of polychlorinated biphenyls from multiple industrial thermal processes.

    Science.gov (United States)

    Liu, Guorui; Zheng, Minghui; Cai, Mingwei; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Du, Bing; Dong, Shujun; Hu, Jicheng; Xiao, Ke

    2013-03-01

    In this study, field measurements were conducted to estimate and characterize the atmospheric emission levels and profiles of polychlorinated biphenyls (PCBs) from multiple industrial thermal processes. The emission levels and profiles of PCBs from five types of thermal processes at twenty-three plants were studied and compared with eight processes reported in our previous studies. Correlation analysis was preformed to identify a marker congener for emission of ΣPCB. A significant correlation was observed between congener CB-118 and ΣPCB (R(2)=0.65 and pprocesses were compared, and this information could be used for studying source-receptor relationships and identifying the specific sources of PCBs. To prioritize the sources for control, the concentrations of PCBs from thirteen industrial thermal sources were compared. The PCB concentrations from secondary zinc smelting and thermal wire reclamation were about one to three order magnitude higher than those of other sources, which suggests that these two sources be given priority in PCB source control. Finally, the atmospheric emission factors of PCBs from the thirteen industrial sources were summarized, and these data will be useful for developing an integrated emission inventory of PCBs.

  17. Modelling the impact of aircraft emissions on atmospheric composition

    Science.gov (United States)

    Wasiuk, D. K.; Lowenberg, M. H.; Shallcross, D. E.

    2012-12-01

    Emissions of the trace gases CO2, CO, H2O, HC, NOx, and SOx that have the potential to perturb large scale atmospheric composition are accumulating in the atmosphere at an unprecedented rate as the demand for air traffic continues to grow. We investigate the global and regional effects of aircraft emissions on the atmosphere and climate using mathematical modelling, sensitivity simulations, and perturbation simulations and present historical and spatial distribution evolution of the global and regional number of departures, fuel burn and emissions. A comprehensive aircraft movement database spanning years 2005 - 2012, covering 225 countries and over 223 million departures on approximately 41000 unique routes serves as a basis for our investigation. We combine air traffic data with output from an aircraft performance model (fuel burn and emissions) including 80 distinct aircraft types, representing 216 of all the aircraft flown in the world in 2005 - 2012. This accounts for fuel burn and emissions for 99.5% of the total number of departures during that time. Simulations are being performed using a state of the art 3D Lagrangian global chemical transport model (CTM) CRI-STOCHEM for simulation of tropospheric chemistry. The model is applied with the CRI (Common Representative Intermediates) chemistry scheme with 220 chemical species, and 609 reactions. This allows us to study in detail the chemical cycles driven by NOx, governing the rate of formation of O3 which controls the production of OH and indirectly determines the lifetime of other greenhouse gases. We also investigate the impact of the Eyjafjallajökull eruption on the European air traffic and present a model response to the perturbation of NOx emissions that followed.

  18. Control of Emissions

    Science.gov (United States)

    Parrish, Clyde F. (Inventor); Chung, Landy (Inventor)

    2013-01-01

    Methods and apparatus utilizing chlorine dioxide and hydrogen peroxide are useful to reduce NOx emissions, as well as SOx and mercury (or other heavy metal) emissions, from combustion flue gas streams.

  19. The contribution of aircraft emissions to the atmospheric sulfur budget

    Energy Technology Data Exchange (ETDEWEB)

    Kjellstroem, E. [Stockholm Univ. (Sweden). Dept. of Meteorology; Feichter, J. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Sausen, R.; Hein, R. [Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1998-01-01

    An atmospheric general circulation model including the atmospheric sulfur cycle has been used to investigate the impact of aircraft sulfur emissions on the global sulfur budget of the atmosphere. The relative contribution from aircraft sulfur to the atmospheric sulfate burden is larger than the ratio between aircraft emissions and surface emissions due to the calculated long turn-over time of aircraft sulfate (about 12 days). However, in terms of the sulfate mass balance, aircraft emissions are small, contributing about 1% of the total sulfate mass north of 40 deg C where the aircraft emissions are largest. Despite this small contribution to sulfate mass, the aircraft emissions could potentially significantly enhance the background number concentration of aerosol particles. Based on the model calculations the increased stratospheric background aerosol mass observed during the last decades can not be explained by increased aircraft sulfur emissions 50 refs, 9 figs, 4 tabs

  20. Atmospheric monitoring for fugitive emissions from geological carbon storage

    Science.gov (United States)

    Loh, Z. M.; Etheridge, D.; Luhar, A.; Leuning, R.; Jenkins, C.

    2013-12-01

    concentration differences across the site. A Bayesian inverse modeling study of the controlled release data accurately retrieved both the location and emission rate of the source. The atmospheric monitoring techniques developed at the Otway Project site are readily transferable to other energy sector developments, such as coal seam gas production, in which fugitive emissions are a concern. Indeed, as the signal to noise is usually better for CH4 than CO2, our monitoring techniques are even more suitable for seeking fugitives from natural gas production.

  1. Coal fired flue gas mercury emission controls

    International Nuclear Information System (INIS)

    Mercury (Hg) is one of the most toxic heavy metals, harmful to both the environment and human health. Hg is released into the atmosphere from natural and anthropogenic sources and its emission control has caused much concern. This book introduces readers to Hg pollution from natural and anthropogenic sources and systematically describes coal-fired flue gas mercury emission control in industry, especially from coal-fired power stations. Mercury emission control theory and experimental research are demonstrated, including how elemental mercury is oxidized into oxidized mercury and the effect of flue gas contents on the mercury speciation transformation process. Mercury emission control methods, such as existing APCDs (air pollution control devices) at power stations, sorbent injection, additives in coal combustion and photo-catalytic methods are introduced in detail. Lab-scale, pilot-scale and full-scale experimental studies of sorbent injection conducted by the authors are presented systematically, helping researchers and engineers to understand how this approach reduces the mercury emissions in flue gas and to apply the methods in mercury emission control at coal-fired power stations.

  2. Coal fired flue gas mercury emission controls

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jiang; Pan, Weiguo [Shanghai Univ. of Electric Power (China); Cao, Yan; Pan, Weiping [Western Kentucky Univ., Bowling Green, KY (United States)

    2015-05-01

    Mercury (Hg) is one of the most toxic heavy metals, harmful to both the environment and human health. Hg is released into the atmosphere from natural and anthropogenic sources and its emission control has caused much concern. This book introduces readers to Hg pollution from natural and anthropogenic sources and systematically describes coal-fired flue gas mercury emission control in industry, especially from coal-fired power stations. Mercury emission control theory and experimental research are demonstrated, including how elemental mercury is oxidized into oxidized mercury and the effect of flue gas contents on the mercury speciation transformation process. Mercury emission control methods, such as existing APCDs (air pollution control devices) at power stations, sorbent injection, additives in coal combustion and photo-catalytic methods are introduced in detail. Lab-scale, pilot-scale and full-scale experimental studies of sorbent injection conducted by the authors are presented systematically, helping researchers and engineers to understand how this approach reduces the mercury emissions in flue gas and to apply the methods in mercury emission control at coal-fired power stations.

  3. Emission control system

    Science.gov (United States)

    Parrish, Clyde F. (Inventor); Chung, J. Landy (Inventor)

    2009-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. The methods and apparatus may further be modified to reduce NOx emissions. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of SOx and heavy metals, while isolating useful by-products streams of sulfuric acid as well as solids for the recovery of the heavy metals. Where removal of NOx emissions is included, nitric acid may also be isolated for use in fertilizer or other industrial applications.

  4. Carbon emissions control strategies

    International Nuclear Information System (INIS)

    This study was undertaken to address a fundamental issue: the cost of slowing climate change. Experts in eight nations were asked to evaluate, using the best economic models available, the prospects for reducing fossil fuel-based carbon emissions in their respective nations. The nations selected as case studies include: the Soviet Union, Poland, the United States, Japan, Hungary, France, the United Kingdom, and Canada. As important contributors to the greenhouse effect, these industrialized nations must find ways to substantially reduce their emissions. This is especially critical given that developing nations' emissions are expected to rise in the coming decades in the search for economic development. Ten papers have been processed separately for inclusion in the appropriate data bases

  5. Constraining CO emission estimates using atmospheric observations

    NARCIS (Netherlands)

    Hooghiemstra, P.B.

    2012-01-01

    We apply a four-dimensional variational (4D-Var) data assimilation system to optimize carbon monoxide (CO) emissions and to reduce the uncertainty of emission estimates from individual sources using the chemistry transport model TM5. In the first study only a limited amount of surface network obs

  6. The travel-related carbon dioxide emissions of atmospheric researchers

    OpenAIRE

    A. Stohl

    2008-01-01

    Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who – like other scientists – rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of carbon dioxide (CO2). In this paper, the CO2 emis...

  7. The effects of energy paths and emission controls and standards on future trends in China's emissions of primary air pollutants

    OpenAIRE

    Zhao, Y.; Zhang, J.; C. P. Nielsen

    2014-01-01

    To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission tre...

  8. Nanosilver emissions to the atmosphere: a new challenge?

    Directory of Open Access Journals (Sweden)

    Walser T.

    2013-04-01

    Full Text Available Atmospheric deposition of silver in Switzerland decreased significantly between 1995 and 2010, but recent increases in nanosilver production present a potentially new emission source of silver. ’While nanosilver is usually integrated in a robust matrix and its release is either controlled, dampened (highly diluted silver in nanosilver textiles or prevented (computer modules, point source emissions of nanosilver can occur at the manufacturing sites. The emission of nanosize particles of particular concern because these particles penetrate deeply in the lungs, and have the potential of causing long-term adverse effects to humans. We investigated local silver emission patterns with bryophytes Brachythecium rutabulum and Hypnum cupressiforme and with bulk (dry and wet deposition measurements of silver, using Bergerhoff samplers, close to a nanosilver manufacturer. With mean values of 0.033 μg g−1, the silver concentrations in the mosses were the same as the background concentration of Switzerland (141 sites. The spatial distribution revealed a decrease in the silver concentrations in moss as a function of increasing distance from the nanosilver manufacturer. The monthly collected bulk depositions were higher in the area of nanosilver production (0.175 ± 0.13 μg m−2 day−1 in comparison to rural (0.105 ± 0.08 μg m−2 day−1 and urban areas (0.113 ± 0.05 μg m−2 day−1 of Eastern Switzerland. Contrary to other areas, the larger monthly variability of the deposition values close to the production site points towards highly variable silver emissions. Subtraction of the silver background deposition results in approximately 60 g deposited silver per year within a perimeter of 4 km from the nanoparticle manufacturer. Along with bulk deposition of silver, we also studied potential morphological changes of the deposited nanosilver. We found silver nanoparticles in the form of environmentally stable silver iodide. We conclude that the

  9. Controlling radiated emissions by design

    CERN Document Server

    Mardiguian, Michel

    2014-01-01

    The 3rd edition of Controlling Radiated Emissions by Design has been updated to reflect the latest changes in the field. New to this edition is material related to technical advances, specifically super-fast data rates on wire pairs, with no increase in RF interference. Throughout the book, details are given to control RF emissions using EMC design techniques. This book retains the step-by-step approach for incorporating EMC into every new design from the ground up. It describes the selection of quieter IC technologies, their implementation into a noise-free printed circuit layout, and the gathering of these into a low emissions package. Also included is how to design an I/O filter, along with connectors and cable considerations. All guidelines are supported throughout with comprehensive calculated examples. Design engineers, EMC specialists, and technicians will benefit from learning about the development of more efficient and economical control of emissions.

  10. Landfill is an important atmospheric mercury emission source

    Institute of Scientific and Technical Information of China (English)

    FENG Xinbin; TANG Shunlin; LI Zhonggen; WANG Shaofeng; LIANG Lian

    2004-01-01

    Since municipal wastes contain refuses with high mercury contents, incineration of municipal wastes becomes the major anthropogenic atmospheric mercury emission source. In China, landfills are however the main way to dispose of municipal wastes. Total gaseous mercury (TGM) concentrations in landfill gas of Gaoyan sanitary landfill located in suburb of Guiyang City were monitored using a high temporal resolved automated mercury analyzer, and mono-methylmercury (MMHg) and dimethylmercury (DMHg) concentrations in landfill gas were also measured using GC coupled with the cold vapor atomic fluorescence (CVAFS) method. Meanwhile, the TGM exchange fluxes between exposed waste and air and the soil surface of the landfill and air, were measured using low Hg blank quartz flux chamber coupled with high temporal resolved automated mercury analyzer technique. TGM concentrations in landfill gas from half year filling area averaged out at 665.52±291.25 ng/m3, which is comparable with TGM concentrations from flue gas of a small coal combustion boiler in Guiyang. The average MMHg and DMHg concentrations averaged out at 2.06±1.82 ng/m3 and 9.50±5.18 ng/m3, respectively. It is proven that mercury emission is the predominant process at the surfaces of both exposed wastes and soil of landfill. Landfills are not only TGM emission source, but also methylmercury emission source to the ambient air. There are two ways to emit mercury to the air from landfills, one is with the landfill gas through landfill gas duct, and the other through soil/air exchange. The Hg emission processes from landfills are controlled by meteorological parameters.

  11. Advanced Emissions Control Development Program

    Energy Technology Data Exchange (ETDEWEB)

    A.P.Evans; K.E. Redinger; M.J. Holmes

    1998-04-01

    The objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. Ideally, the project aim is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPS), fabric filters (baghouse), and wet flue gas desulfurization. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate and hydrogen chloride. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on the evaluation of mercury and several other air toxics emissions. The AECDP is jointly funded by the United States Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (oCDO), and Babcock& Wilcox-a McDermott company (B&W).

  12. Atmospheric verification of anthropogenic CO2 emission trends

    Science.gov (United States)

    Francey, Roger J.; Trudinger, Cathy M.; van der Schoot, Marcel; Law, Rachel M.; Krummel, Paul B.; Langenfelds, Ray L.; Paul Steele, L.; Allison, Colin E.; Stavert, Ann R.; Andres, Robert J.; Rödenbeck, Christian

    2013-05-01

    International efforts to limit global warming and ocean acidification aim to slow the growth of atmospheric CO2, guided primarily by national and industry estimates of production and consumption of fossil fuels. Atmospheric verification of emissions is vital but present global inversion methods are inadequate for this purpose. We demonstrate a clear response in atmospheric CO2 coinciding with a sharp 2010 increase in Asian emissions but show persisting slowing mean CO2 growth from 2002/03. Growth and inter-hemispheric concentration difference during the onset and recovery of the Global Financial Crisis support a previous speculation that the reported 2000-2008 emissions surge is an artefact, most simply explained by a cumulative underestimation (~ 9PgC) of 1994-2007 emissions; in this case, post-2000 emissions would track mid-range of Intergovernmental Panel on Climate Change emission scenarios. An alternative explanation requires changes in the northern terrestrial land sink that offset anthropogenic emission changes. We suggest atmospheric methods to help resolve this ambiguity.

  13. Advanced Emissions Control Development Program: Mercury Control

    International Nuclear Information System (INIS)

    McDermott Technology, Inc. (a subsidiary of Babcock ampersand Wilcox) is conducting the Advanced Emissions Control Development Project (AECDP) which is aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPS) from coal-fired electric utility plants. The need for such controls may arise as the US Environmental Protection Agency (EPA) proceeds with implementation of requirements set forth in the Clean Air Act Amendments (CAAA's) of 1990. Promulgation of air toxics emissions regulations for electric utility plants could dramatically impact utilities burning coal, their industrial and residential customers, and the coal industry. AECDP project work will supply the information needed by utilities to respond to potential HAPs regulations in a timely, cost-effective, enviromnentally-sound manner which supports the continued use of the Nation's abundant reserves of coal, such as those in the State of Ohio. The development work is being carried out using the 10 MW Clean Environment Development Facility wherein air toxics emissions control strategies can be developed under controlled conditions. The specific objectives of the project are to (1) measure and understand production and partitioning of air toxics species for a variety of coals, (2) optimize the air toxics removal performance of conventional flue gas cleanup systems, (3) develop advanced air toxics emissions control concepts, (4) develop and validate air toxics emissions measurement and monitoring techniques, and (5) establish a comprehensive, self-consistent air toxics data library. This project is supported by the Department of Energy, the Ohio Coal Development Office within the Ohio Department of Development and Babcock ampersand Wilcox. A comprehensive assessment of HAP emissions from coal-fired electric utility boilers sponsored by the Department of Energy and the Electric Power Research Institute concluded that with the exception of

  14. Environmental controls over methanol emission from leaves

    Directory of Open Access Journals (Sweden)

    P. Harley

    2007-12-01

    Full Text Available Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmental factors which control them require further elucidation.

    Using a temperature-controlled leaf enclosure, we measured methanol emissions from leaves of six plant species by proton transfer reaction mass spectrometry, with simultaneous measurements of leaf evapotranspiration and stomatal conductance. Rates of emission at 30°C varied from 0.2 to 38 μg g (dry mass−1 h−1, with higher rates measured on young leaves, consistent with the production of methanol via pectin demethylation in expanding foliage. On average, emissions increased by a factor of 2.3 for each 10°C increase in leaf temperature. At constant temperature, emissions were also correlated with co-varying incident photosynthetic photon flux density and rates of stomatal conductance. The data were analyzed using the emission model developed by Niinemets and Reichstein (2003a, b, with the incorporation of a methanol production term that increased exponentially with temperature. It was concluded that control of emissions, during daytime, was shared by leaf temperature and stomatal conductance, although rates of production may also vary diurnally in response to variations in leaf growth rate in expanding leaves. The model, which generally provided reasonable simulations of the measured data during the day, significantly overestimated emissions on two sets of measurements made through the night, suggesting that production rates of methanol were reduced at night, perhaps because leaf growth was reduced or possibly through a direct effect of light on production

  15. Environmental controls over methanol emission from leaves

    Directory of Open Access Journals (Sweden)

    P. Harley

    2007-08-01

    Full Text Available Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmental factors which control them require further elucidation.

    Using a temperature-controlled leaf enclosure, we measured methanol emissions from leaves of six plant species by proton transfer reaction mass spectrometry, with simultaneous measurements of leaf evapotranspiration and stomatal conductance. Rates of emission at 30°C varied from 0.3 to 38 μg g (dry mass−1 h−1, with higher rates measured on young leaves, consistent with the production of methanol via pectin demethylation in expanding foliage. On average, emissions increased by a factor of 2.4 for each 10°C increase in leaf temperature. At constant temperature, emissions were also correlated with co-varying incident photosynthetic photon flux density and rates of stomatal conductance. The data were analyzed using the emission model developed by Niinemets and Reichstein (2003a, b, with the incorporation of a methanol production term that increased exponentially with temperature. It was concluded that control of emissions, during daytime, was shared by leaf temperature and stomatal conductance, although rates of production may also vary diurnally in response to variations in leaf growth rate in expanding leaves. The model, which generally provided reasonable simulations of the measured data during the day, significantly overestimated emissions on two sets of measurements made through the night, suggesting that production rates of methanol were reduced at night, perhaps because leaf growth was reduced or possibly through a direct effect of light on production

  16. The effects of energy paths and emission controls and standards on future trends in China's emissions of primary air pollutants

    OpenAIRE

    Zhao, Y.; Zhang, J.; C. P. Nielsen

    2014-01-01

    To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the fu...

  17. Mercury enrichment and its effects on atmospheric emissions in cement plants of China

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Wu, Qingru; Hao, Jiming

    2014-08-01

    The cement industry is one of the most significant anthropogenic sources of atmospheric mercury emissions worldwide. In this study of three typical Chinese cement plants, mercury in kiln flue gas was sampled using the Ontario Hydro Method (OHM), and solid samples were analyzed. Particulate matter recycling, preheating of raw materials, and the use of coal and flue gas desulfurization derived gypsum contributed to emissions of Hg in the air and to accumulation in cement. Over 90% of the mercury input was emitted into the atmosphere. Mercury emission factors were 0.044-0.072 g/t clinker for the test plants. The major species emitted into the atmosphere from cement plants is oxidized mercury, accounting for 61%-91% of the total mercury in flue gas. The results of this study help improve the accuracy of the mercury emission inventory in China and provide useful information for developing mercury controls.

  18. Atmospheric Sulfur Hexafluoride: Measurements and Emission Estimates from 1970 - 2008

    Science.gov (United States)

    Rigby, M. L.; Prinn, R. G.; Muhle, J.; Miller, B. R.; Dlugokencky, E. J.; Krummel, P. B.; Steele, L. P.; Fraser, P. J.; Leist, M.; Weiss, R. F.; Harth, C. M.; O'Doherty, S. J.; Greally, B. R.; Simmonds, P. G.; Derek, N.; Vollmer, M. K.; Kim, J.; Kim, K.; Porter, L. W.

    2009-12-01

    We present an air history of atmospheric sulfur hexafluoride (SF6) from the early 1970s through 2008. During this period, concentrations of this extremely potent and long-lived greenhouse gas have increased by more than an order of magnitude, and its growth has accelerated in recent years. In this study, historical concentrations are determined from archived air samples measured on the Advanced Global Atmospheric Gases Experiment (AGAGE) ‘Medusa’ gas chromatography/mass spectrometry system. These data are combined with modern high-frequency measurements from the AGAGE and National Oceanic and Atmospheric Administration (NOAA) in situ networks and ˜weekly samples from the NOAA flask network, to produce a unique time series with increasing global coverage spanning almost four decades. Using the three-dimensional chemical transport Model for Ozone and Related Tracers (MOZART v4.5) and a discrete Kalman filter, we derive estimates of the annual emission strength of SF6 on hemispheric scales from 1970 - 2004 and on continental scales from 2004 - 2008. Our emission estimates are compared to the recently compiled Emissions Database for Global Atmospheric Research (EDGAR v4), and emissions reported under the United Nations Framework Convention on Climate Change (UNFCCC). The cause of the recent growth rate increase is also investigated, indicating that the origin of the required emissions rise is likely to be South-East Asia.

  19. Historical atmospheric mercury emissions and depositions in North America compared to mercury accumulations in sedimentary records

    Science.gov (United States)

    Pirrone, Nicola; Allegrini, Ivo; Keeler, Gerald J.; Nriagu, Jerome O.; Rossmann, Ronald; Robbins, John A.

    Gold and silver production in North America (included United States, Canada and Mexico) released a large amount of mercury to the atmosphere until well into this century when mercury (Hg) amalgamation was replaced by cyanide concentration. Since then, emissions from industries have been the dominant anthropogenic sources of atmospheric Hg in North America as a whole. Past Hg emissions from gold and silver extractions in North America during the 1800s do not show a clear evidence of atmospheric deposition occurred at the coring sites considered in this study. Estimated atmospheric emissions of Hg in North America peaked in 1879 (at about 1708 t yr -1) and 1920 (at about 940 t yr -1), primarily due to Hg emissions from gold and silver mining. After the Great Economic Depression (1929) Hg emissions peaked again in the 1947 (274 t yr -1), in 1970 (325 t yr -1) and in 1989 (330 t yr -1) as result of increased Hg emissions from industrial sources, though improvements in the emissions control technology in United States and Canada have been substantial. Estimates of total atmospheric deposition fluxes of Hg to water and terrestrial receptors were in the range of 14.3-19.8 μg m -2 yr -1 in North America as a whole, and averaged 135 μg m -2 yr -1 (global background + local emissions) in the Great Lakes. These values were in good agreement with recent estimates reported in literature. The comparison of atmospheric Hg deposition fluxes with Hg accumulation rates in sediment cores suggests that atmospheric deposition was the major source of Hg entering the lakes system at coring sites, however, important contributions to Lake Ontario sediment cores sites from 1940 to 1970 were likely originated from local point sources (i.e. direct discharges).

  20. Atmospheric inverse estimates of methane emissions from Central California

    Science.gov (United States)

    Zhao, Chuanfeng; Andrews, Arlyn E.; Bianco, Laura; Eluszkiewicz, Janusz; Hirsch, Adam; MacDonald, Clinton; Nehrkorn, Thomas; Fischer, Marc L.

    2009-08-01

    Methane mixing ratios measured at a tall tower are compared to model predictions to estimate surface emissions of CH4 in Central California for October-December 2007 using an inverse technique. Predicted CH4 mixing ratios are calculated based on spatially resolved a priori CH4 emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH4 emissions. Three inverse model estimates of CH4 emissions are reported. First, linear regressions of modeled and measured CH4 mixing ratios obtain slopes of 0.73 ± 0.11 and 1.09 ± 0.14 using California-specific and Edgar 3.2 emission maps, respectively, suggesting that actual CH4 emissions were about 37 ± 21% higher than California-specific inventory estimates. Second, a Bayesian "source" analysis suggests that livestock emissions are 63 ± 22% higher than the a priori estimates. Third, a Bayesian "region" analysis is carried out for CH4 emissions from 13 subregions, which shows that inventory CH4 emissions from the Central Valley are underestimated and uncertainties in CH4 emissions are reduced for subregions near the tower site, yielding best estimates of flux from those regions consistent with "source" analysis results. The uncertainty reductions for regions near the tower indicate that a regional network of measurements will be necessary to provide accurate estimates of surface CH4 emissions for multiple regions.

  1. Atmospheric Inverse Estimates of Methane Emissions from Central California

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chuanfeng; Andrews, Arlyn E.; Bianco, Laura; Eluszkiewicz, Janusz; Hirsch, Adam; MacDonald, Clinton; Nehrkorn, Thomas; Fischer, Marc L.

    2008-11-21

    Methane mixing ratios measured at a tall-tower are compared to model predictions to estimate surface emissions of CH{sub 4} in Central California for October-December 2007 using an inverse technique. Predicted CH{sub 4} mixing ratios are calculated based on spatially resolved a priori CH{sub 4} emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH{sub 4} emissions. Three inverse model estimates of CH{sub 4} emissions are reported. First, linear regressions of modeled and measured CH{sub 4} mixing ratios obtain slopes of 0.73 {+-} 0.11 and 1.09 {+-} 0.14 using California specific and Edgar 3.2 emission maps respectively, suggesting that actual CH{sub 4} emissions were about 37 {+-} 21% higher than California specific inventory estimates. Second, a Bayesian 'source' analysis suggests that livestock emissions are 63 {+-} 22% higher than the a priori estimates. Third, a Bayesian 'region' analysis is carried out for CH{sub 4} emissions from 13 sub-regions, which shows that inventory CH{sub 4} emissions from the Central Valley are underestimated and uncertainties in CH{sub 4} emissions are reduced for sub-regions near the tower site, yielding best estimates of flux from those regions consistent with 'source' analysis results. The uncertainty reductions for regions near the tower indicate that a regional network of measurements will be necessary to provide accurate estimates of surface CH{sub 4} emissions for multiple regions.

  2. The travel-related carbon dioxide emissions of atmospheric researchers

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2008-11-01

    Full Text Available Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who – like other scientists – rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of CO2. In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc. were calculated for the years 2005–2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.

  3. The travel-related carbon dioxide emissions of atmospheric researchers

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2008-04-01

    Full Text Available Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who – like other scientists – rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of carbon dioxide (CO2. In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc. were calculated for the years 2005–2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.

  4. Future trends of global atmospheric antimony emissions from anthropogenic activities until 2050

    Science.gov (United States)

    Zhou, Junrui; Tian, Hezhong; Zhu, Chuanyong; Hao, Jiming; Gao, Jiajia; Wang, Yong; Xue, Yifeng; Hua, Shenbin; Wang, Kun

    2015-11-01

    This paper presents the scenario forecast of global atmospheric antimony (Sb) emissions from anthropogenic activities till 2050. The projection scenarios are built based on the comprehensive global antimony emission inventory for the period 1995-2010 which is reported in our previous study. Three scenarios are set up to investigate the future changes of global antimony emissions as well as their source and region contribution characteristics. Trends of activity levels specified as 5 primary source categories are projected by combining the historical trend extrapolation with EIA International energy outlook 2013, while the source-specific dynamic emission factors are determined by applying transformed normal distribution functions. If no major changes in the efficiency of emission control are introduced and keep current air quality legislations (Current Legislation scenario), global antimony emissions will increase by a factor of 2 between 2010 and 2050. The largest increase in Sb emissions is projected from Asia due to large volume of nonferrous metals production and waste incineration. In case of enforcing the pollutant emission standards (Strengthened Control scenario), global antimony emissions in 2050 will stabilize with that of 2010. Moreover, we can anticipate further declines in Sb emissions for all continents with the best emission control performances (Maximum Feasible Technological Reduction scenario). Future antimony emissions from the top 10 largest emitting countries have also been calculated and source category contributions of increasing emissions of these countries present significant diversity. Furthermore, global emission projections in 2050 are distributed within a 1° × 1°latitude/longitude grid. East Asia, Western Europe and North America present remarkable differences in emission intensity under the three scenarios, which implies that source-and-country specific control measures are necessary to be implemented for abating Sb emissions from

  5. Atmospheric Verification of Point Source Fossil Fuel CO2 Emissions

    Science.gov (United States)

    Turnbull, J. C.; Keller, E. D.; Norris, M. W.; Wiltshire, R.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.

    2015-12-01

    Large point sources (electricity generation and large-scale industry) make up roughly one third of all fossil fuel CO2 (CO2ff) emissions. Currently, these emissions are determined from self-reported inventory data, and sometimes from smokestack emissions monitoring, and the uncertainty in emissions from individual power plants is about 20%. We examine the utility of atmospheric 14C measurements combined with atmospheric transport modelling as a tool for independently quantifying point source CO2ff emissions, to both improve the accuracy of the reported emissions and for verification as we move towards a regulatory environment. We use the Kapuni Gas Treatment Facility as a test case. It is located in rural New Zealand with no other significant fossil fuel CO2 sources nearby, and emits CO2ff at ~0.1 Tg carbon per year. We use several different sampling methods to determine the 14C and hence the CO2ff content downwind of the emission source: grab flask samples of whole air; absorption of CO2 into sodium hydroxide integrated over many hours; and plant material which faithfully records the 14C content of assimilated CO2. We use a plume dispersion model to compare the reported emissions with our observed CO2ff mole fractions. We show that the short-term variability in plume dispersion makes it difficult to interpret the grab flask sample results, whereas the variability is averaged out in the integrated samples and we obtain excellent agreement between the reported and observed emissions, indicating that the 14C method can reliably be used to evaluated point source emissions.

  6. Primary production control of methane emission from wetlands

    Science.gov (United States)

    Whiting, G. J.; Chanton, J. P.

    1993-01-01

    Based on simultaneous measurements of CO2 and CH4 exchange in wetlands extending from subarctic peatlands to subtropical marshes, a positive correlation between CH4 emission and net ecosystem production is reported. It is suggested that net ecosystem production is a master variable integrating many factors which control CH4 emission in vegetated wetlands. It is found that about 3 percent of the daily net ecosystem production is emitted back to the atmosphere as CH4. With projected stimulation of primary production and soil microbial activity in wetlands associated with elevated atmospheric CO2 concentration, the potential for increasing CH4 emission from inundated wetlands, further enhancing the greenhouse effect, is examined.

  7. Characteristic emission enhancement in the atmosphere with Rn trace using metal assisted LIBS

    International Nuclear Information System (INIS)

    Several characteristic emission lines from the metal targets (Cu, Zn and Pb) were investigated in trace presence of radon gas in the atmospheric air, using Q-SW Nd:YAG laser induced plasma inside a control chamber. The emission lines of metal species are noticeably enhanced in (Rn+air), relative to those in the synthetic air alone. Similar spectra were also taken in various sub-atmospheric environments in order to determine the optimum pressure for enhancement. Solid-state nuclear track detectors were also employed to count the tracks due to alpha particles for the activity assessment

  8. Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions.

    Science.gov (United States)

    Zhang, Yanxu; Jacob, Daniel J; Horowitz, Hannah M; Chen, Long; Amos, Helen M; Krabbenhoft, David P; Slemr, Franz; St Louis, Vincent L; Sunderland, Elsie M

    2016-01-19

    Observations of elemental mercury (Hg(0)) at sites in North America and Europe show large decreases (∼ 1-2% y(-1)) from 1990 to present. Observations in background northern hemisphere air, including Mauna Loa Observatory (Hawaii) and CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) aircraft flights, show weaker decreases (flat or increasing emissions over that period. However, the inventories have three major flaws: (i) they do not account for the decline in atmospheric release of Hg from commercial products; (ii) they are biased in their estimate of artisanal and small-scale gold mining emissions; and (iii) they do not properly account for the change in Hg(0)/Hg(II) speciation of emissions from coal-fired utilities after implementation of emission controls targeted at SO2 and NOx. We construct an improved global emission inventory for the period 1990 to 2010 accounting for the above factors and find a 20% decrease in total Hg emissions and a 30% decrease in anthropogenic Hg(0) emissions, with much larger decreases in North America and Europe offsetting the effect of increasing emissions in Asia. Implementation of our inventory in a global 3D atmospheric Hg simulation [GEOS-Chem (Goddard Earth Observing System-Chemistry)] coupled to land and ocean reservoirs reproduces the observed large-scale trends in atmospheric Hg(0) concentrations and in Hg(II) wet deposition. The large trends observed in North America and Europe reflect the phase-out of Hg from commercial products as well as the cobenefit from SO2 and NOx emission controls on coal-fired utilities. PMID:26729866

  9. Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions

    Science.gov (United States)

    Yanxu Zhang,; Daniel J. Jacob,; Hannah M. Horowitz,; Long Chen,; Helen M. Amos,; Krabbenhoft, David P.; Franz Slemr,; Vincent L. St. Louis,; Elsie M. Sunderland,

    2015-01-01

    Observations of elemental mercury (Hg0) at sites in North America and Europe show large decreases (∼1–2% y−1) from 1990 to present. Observations in background northern hemisphere air, including Mauna Loa Observatory (Hawaii) and CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) aircraft flights, show weaker decreases (inventories indicating flat or increasing emissions over that period. However, the inventories have three major flaws: (i) they do not account for the decline in atmospheric release of Hg from commercial products; (ii) they are biased in their estimate of artisanal and small-scale gold mining emissions; and (iii) they do not properly account for the change in Hg0/HgII speciation of emissions from coal-fired utilities after implementation of emission controls targeted at SO2 and NOx. We construct an improved global emission inventory for the period 1990 to 2010 accounting for the above factors and find a 20% decrease in total Hg emissions and a 30% decrease in anthropogenic Hg0 emissions, with much larger decreases in North America and Europe offsetting the effect of increasing emissions in Asia. Implementation of our inventory in a global 3D atmospheric Hg simulation [GEOS-Chem (Goddard Earth Observing System-Chemistry)] coupled to land and ocean reservoirs reproduces the observed large-scale trends in atmospheric Hg0 concentrations and in HgII wet deposition. The large trends observed in North America and Europe reflect the phase-out of Hg from commercial products as well as the cobenefit from SO2 and NOx emission controls on coal-fired utilities.

  10. Current submarine atmosphere control technology.

    Science.gov (United States)

    Mazurek, W

    1998-01-01

    Air purification in submarines was introduced towards the end of World War II and was limited to the use of soda lime for the removal of carbon dioxide and oxygen candles for the regeneration of oxygen. The next major advances came with the advent of nuclear-powered submarines. These included the development of regenerative and, sometimes, energy-intensive processes for comprehensive atmosphere revitalization. With the present development of conventional submarines using air-independent propulsion there is a requirement for air purification similar to that of the nuclear-powered submarines but it is constrained by limited power and space. Some progress has been made in the development of new technology and the adoption of air purification equipment used in the nuclear-powered submarines for this application.

  11. Guidelines on reducing atmospheric emissions from oil and gas facilities

    International Nuclear Information System (INIS)

    These guidelines have been produced by the United Kingdom Offshore Operators Association (UKOOA) to assist operators in improving emissions performance in the upstream oil and gas industry. The principal environmental concerns relevant to activities within the industry are: global climate change which could result from carbon dioxide and methane emissions; stratospheric ozone depletion caused by halons and chlorofluorocarbons; ground level ozone formation from reactions between volatile organic compounds and oxides of nitrogen; acidification caused by gases such as oxides of nitrogen and sulphur. The guidelines are set out under the following main areas: environmental concerns and legislative responses; atmospheric emissions sources; facility design for improved performance; improving performance of existing operations; cost-effectiveness of air emission reduction projects. (UK)

  12. Global emissions of mercury to the atmosphere in 2005 and their 2020 scenarios

    Science.gov (United States)

    Pacyna, Jozef M.; Pacyna, Elisabeth G.; Sundseth, Kyrre; Munthe, John; Wilson, Simon; Leaner, Joy

    2010-05-01

    About the three quarters of the total anthropogenic emissions of mercury in the year 2005 estimated to be 1930 tonnes comes from sources where mercury is emitted as a by-product, and the rest is emitted during various applications of mercury. The largest emissions of Hg to the global atmosphere occur from combustion of fossil fuels, mainly coal in utility, industrial, and residential boilers (almost 47 %), followed by artisanal mining (almost 17 %), non-ferrous metal production, including gold production (13.5%) and cement production (about 9.5 %). Doing nothing for the improvement of the Hg emission reductions (so-called Status Quo - SQ scenario) will cause an increase of the emissions in 2020 by almost 100 % compared to the 2020 Extended Emission Control (EXEC) emission reduction scenario. Even larger increase is estimated when the 2020 SQ scenario of Hg emissions is compared with the 2020 Maximum Feasible Technical Reduction (MFTR) emission reduction scenario. The EXEC scenario assumes economic progress at a rate dependent on the future development of industrial technologies and emission control technologies, i.e. mercury-reducing technology currently generally employed throughout Europe and North America would be implemented elsewhere. It further assumes that emissions control measures currently implemented or committed to in Europe to reduce mercury emission to air or water would be implemented around the world. The MFTR scenario assumes implementation of all solutions/ measures leading to the maximum degree of reduction of mercury emissions and its loads discharged to any environment; cost is taken into account but only as a secondary consideration. Emissions of Hg in various industrial sectors, such as cement production and metal manufacturing in the year 2020 can be 2 to 3 times larger if nothing will be done to improve emission control in comparison with the EXEC scenario.

  13. Reactive nitrogen in atmospheric emission inventories – a review

    Directory of Open Access Journals (Sweden)

    S. Reis

    2009-05-01

    Full Text Available Excess reactive Nitrogen (Nr has become one of the most pressing environmental problems leading to air pollution, acidification and eutrophication of ecosystems, biodiversity impacts, leaching of nitrates into groundwater and global warming. This paper investigates how current inventories cover emissions of Nr to the atmosphere in Europe, the United States of America, and The People's Republic of China. The focus is on anthropogenic sources, assessing the state-of-the-art of quantifying emissions of Ammonia (NH3, Nitrogen Oxides (NOx and Nitrous Oxide (N2O, the different purposes for which inventories are compiled, and to which extent current inventories meet the needs of atmospheric dispersion modelling. The paper concludes with a discussion of uncertainties involved and a brief outlook on emerging trends in the three regions investigated is conducted.

    Key issues are substantial differences in the overall magnitude, but as well in the relative sectoral contribution of emissions in the inventories that have been assessed. While these can be explained by the use of different methodologies and underlying data (e.g. emission factors or activity rates, they may lead to quite different results when using the emission datasets to model ambient air quality or the deposition with atmospheric dispersion models. Hence, differences and uncertainties in emission inventories are not merely of academic interest, but can have direct policy implications when the development of policy actions is based on these model results.

    The robustness of emission estimates varies greatly between substances, regions and emission source sectors. This has implications for the direction of future research needs and indicates how existing gaps between modelled and measured concentration or deposition rates could be most efficiently addressed.

    The observed current trends in emissions display decreasing NO

  14. Airborne interferometer for atmospheric emission and solar absorption.

    Science.gov (United States)

    Keith, D W; Dykema, J A; Hu, H; Lapson, L; Anderson, J G

    2001-10-20

    The interferometer for emission and solar absorption (INTESA) is an infrared spectrometer designed to study radiative transfer in the troposphere and lower stratosphere from a NASA ER-2 aircraft. The Fourier-transform spectrometer (FTS) operates from 0.7 to 50 mum with a resolution of 0.7 cm(-1). The FTS observes atmospheric thermal emission from multiple angles above and below the aircraft. A heliostat permits measurement of solar absorption spectra. INTESA's calibration system includes three blackbodies to permit in-flight assessment of radiometric error. Results suggest that the in-flight radiometric accuracy is ~0.5 K in the mid-infrared.

  15. European emissions of halogenated greenhouse gases inferred from atmospheric measurements.

    Science.gov (United States)

    Keller, Christoph A; Hill, Matthias; Vollmer, Martin K; Henne, Stephan; Brunner, Dominik; Reimann, Stefan; O'Doherty, Simon; Arduini, Jgor; Maione, Michela; Ferenczi, Zita; Haszpra, Laszlo; Manning, Alistair J; Peter, Thomas

    2012-01-01

    European emissions of nine representative halocarbons (CFC-11, CFC-12, Halon 1211, HCFC-141b, HCFC-142b, HCFC-22, HFC-125, HFC-134a, HFC-152a) are derived for the year 2009 by combining long-term observations in Switzerland, Italy, and Ireland with campaign measurements from Hungary. For the first time, halocarbon emissions over Eastern Europe are assessed by top-down methods, and these results are compared to Western European emissions. The employed inversion method builds on least-squares optimization linking atmospheric observations with calculations from the Lagrangian particle dispersion model FLEXPART. The aggregated halocarbon emissions over the study area are estimated at 125 (106-150) Tg of CO(2) equiv/y, of which the hydrofluorocarbons (HFCs) make up the most important fraction with 41% (31-52%). We find that chlorofluorocarbon (CFC) emissions from banks are still significant and account for 35% (27-43%) of total halocarbon emissions in Europe. The regional differences in per capita emissions are only small for the HFCs, while emissions of CFCs and hydrochlorofluorocarbons (HCFCs) tend to be higher in Western Europe compared to Eastern Europe. In total, the inferred per capita emissions are similar to estimates for China, but 3.5 (2.3-4.5) times lower than for the United States. Our study demonstrates the large benefits of adding a strategically well placed measurement site to the existing European observation network of halocarbons, as it extends the coverage of the inversion domain toward Eastern Europe and helps to better constrain the emissions over Central Europe.

  16. X-ray emission of the night terrestrial atmosphere (experiment

    Science.gov (United States)

    Pugacheva, Galina; Pankov, Vladislav; Prokhin, Vladimir; Gusev, Anatoly; Spjeldvik, Walther; Martin, Inacio; Pugacheva, Galina

    A spectrometer RPS-1 onboard the LEO "CORONAS-F" satellite monitored solar X-rays in the energy range 3-31.5 keV (31.07.2001 - 06.12.2005 years) using CdTe solid state detector with thermoelectric semiconductor micro cooler. The device registered X-ray emission of the upper atmosphere at shadowed branches of the orbit. When touching the inner radiation belt in the South Atlantic anomaly and at high latitudes the device registered signals produced by energetic trapped particles. Among the other factors determining the flux registered by the device there are solar activity, the Earth position relatively the Sun (seasonality), satellite position, the telescope orientation relatively nadir when entering and leaving the Earth's shadow. This paper presents global maps of the atmospheric X-ray emission in four energy intervals 3-5; 5-8, 8-16, and 16-31.5 keV during the total period from 23.03.2002 up to 23.03.2003 and periods of 23.03.2002-23.09.2002 and 23.09.2002-23.03/2003 corresponding "summer" and "winter" seasons in the Northern hemisphere. The energy of the registered emission does not exceed 8 keV out of the radiation belt. Comparison of the seasonal maps reveals a gap between the radiation belts at low altitudes ( 500km) in the summer of 2002 probably due to compression of the magnetosphere and/or the seasonal atmospheric temperature changesin time period close to the maximum of solar activity and the absence of the gap in summer of 2004 year near to solar activity minimum. A weak emission of 3-5 keV x-rays in the gap within radiation belts is produced by interaction of galactic cosmic rays with the atmosphere.

  17. Exhaust emission control and diagnostics

    Science.gov (United States)

    Mazur, Christopher John; Upadhyay, Devesh

    2006-11-14

    A diesel engine emission control system uses an upstream oxidation catalyst and a downstream SCR catalyst to reduce NOx in a lean exhaust gas environment. The engine and upstream oxidation catalyst are configured to provide approximately a 1:1 ratio of NO to NO2 entering the downstream catalyst. In this way, the downstream catalyst is insensitive to sulfur contamination, and also has improved overall catalyst NOx conversion efficiency. Degradation of the system is determined when the ratio provided is no longer near the desired 1:1 ratio. This condition is detected using measurements of engine operating conditions such as from a NOx sensor located downstream of the catalysts. Finally, control action to adjust an injected amount of reductant in the exhaust gas based on the actual NO to NO2 ratio upstream of the SCR catalyst and downstream of the oxidation catalyst.

  18. Pulsed, atmospheric pressure plasma source for emission spectrometry

    Science.gov (United States)

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2004-05-11

    A low-power, plasma source-based, portable molecular light emission generator/detector employing an atmospheric pressure pulsed-plasma for molecular fragmentation and excitation is described. The average power required for the operation of the plasma is between 0.02 W and 5 W. The features of the optical emission spectra obtained with the pulsed plasma source are significantly different from those obtained with direct current (dc) discharge higher power; for example, strong CH emission at 431.2 nm which is only weakly observed with dc plasma sources was observed, and the intense CN emission observed at 383-388 nm using dc plasma sources was weak in most cases. Strong CN emission was only observed using the present apparatus when compounds containing nitrogen, such as aniline were employed as samples. The present apparatus detects dimethylsulfoxide at 200 ppb using helium as the plasma gas by observing the emission band of the CH radical. When coupled with a gas chromatograph for separating components present in a sample to be analyzed, the present invention provides an apparatus for detecting the arrival of a particular component in the sample at the end of the chromatographic column and the identity thereof.

  19. Atmospheric emissions from the upstream oil and gas industry

    International Nuclear Information System (INIS)

    The results are presented of a study set up to determine the nature and levels of atmospheric emissions resulting from United Kingdom oil and gas exploration and production activities. The study was commissioned by the UK Offshore Operators Association. Emissions by the upstream oil and gas industry of common pollutants, such as carbon monoxide, sulphur dioxide and nitrous oxide, and ozone depletion chemicals were shown in each case to be less than 1% of total UK emissions. Greenhouse gas emissions in the industry arise mainly from production operations with a small but significant contribution from onshore activities. Carbon dioxide is the major component followed in descending order by nitrogen oxides, methane and volatile organic compounds. In 1991, these emissions formed 3.2%, 4.6%, 2.9% and 2.8% of the UK totals respectively; overall this represented only about 3% of UK global warming emissions. The evidence of this study illustrates that the industry, which produces 67% of the UK's primary energy, is successfully managing its operations in an environmentally responsible way. (3 figures, 3 tables) (UK)

  20. Osmium isotopic tracing of atmospheric emissions from an aluminum smelter

    Science.gov (United States)

    Gogot, Julien; Poirier, André; Boullemant, Amiel

    2015-09-01

    We present for the first time the use of osmium isotopic composition as a tracer of atmospheric emissions from an aluminum smelter, where alumina (extracted from bauxite) is reduced through electrolysis into metallic aluminum using carbonaceous anodes. These anodes are consumed in the process; they are made of petroleum coke and pitch and have high Re/Os elementary ratio. Due to the relatively large geological age of their source material, their osmium shows a high content of radiogenic 187Os produced from in situ187Re radioactive decay. The radiogenic isotopic composition (187Os/188Os ∼ 2.5) of atmospheric particulate emissions from this smelter is different from that of other typical anthropogenic osmium sources (that come from ultramafic geological contexts with unradiogenic Os isotopes, e.g., 187Os/188Os < 0.2) and also different from average eroding continental crust 187Os/188Os ratios (ca. 1.2). This study demonstrates the capacity of osmium measurements to monitor particulate matter emissions from the Al-producing industry.

  1. Changes in Emissions in Megacities during the Past Decades: Impact on the Distribution of Atmospheric Compounds

    Science.gov (United States)

    Doumbia, E. H. T.; Granier, C.; Sindelarova, K.; Tilmes, S.; Bouarar, I.; Richter, A.; Hilboll, A.; Conley, A. J.; Garcia, R. R.; Kinnison, D. E.; Lamarque, J. F.; Marsh, D. R.; Smith, A. K.; Neely, R.; Turnock, S.

    2015-12-01

    The surface emissions of atmospheric compounds have changed dramatically in many world regions during the past decades. We will evaluate these changes through an analysis of different global and regional anthropogenic emissions inventories, focusing on several megacities. In European and North American megacities, surface emissions of chemical compounds have decreased significantly, while they have increased in many other megacities in different parts of the world. Simulations performed with the CAM4-Chem Community Earth System Model will be used to evaluate the impact of the changes in emissions on the distributions chemical compounds in different megacities. These simulations were performed as part of the Chemistry-Climate Model Initiative (CCMI), a project of the International Global Atmospheric Chemistry Project (IGAC). The analysis of the simulations will focus more particularly on nitrogen dioxide: this species has been observed by satellite measurements since the late 1990s. Model results and satellite observations will be analysed for everal megacities in Europe and North America, where strong emission controls have been implemented. Other megacities in China, India, Africa and South America, where few emission regulations have been enforced have seen large increases in their emissions: we will evaluate the consistency of the model simulations and satellite observations of NO2 in these cities.

  2. Química atmosférica na Amazônia: a floresta e as emissões de queimadas controlando a composição da atmosfera amazônica Atmospheric chemistry in Amazonia: the forest and the biomass burning emissions controlling the composition of the Amazonian atmosphere

    Directory of Open Access Journals (Sweden)

    Paulo Artaxo

    2005-06-01

    Full Text Available Entender os processos naturais que regulam a composição da atmosfera é crítico para que se possa desenvolver uma estratégia de desenvolvimento sustentável na região. As grandes emissões de gases e partículas durante a estação seca provenientes das queimadas alteram profundamente a composição da atmosfera amazônica na maior parte de sua área. As concentrações de partículas de aerossóis e gases traço aumentam por fatores de 2 a 8 em grandes áreas, afetando os mecanismos naturais de uma série de processos atmosféricos na região amazônica. Os mecanismos de formação de nuvens, por exemplo, são profundamente alterados quando a concentração de núcleos de condensação de nuvens (NCN passa de 200 a 300 NCN/cm³ na estação chuvosa para 5.000-10.000 NCN/centímetro cúbico na estação seca. As gotas de nuvens sofrem uma redução de tamanho de 18 a 25 micrômetros para 5 a 10 micrômetros, diminuindo a eficiência do processo de precipitação e suprimindo a formação de nuvens. A concentração de ozônio, um gás importante para a saúde da floresta amazônica passa de cerca de 12 partes por bilhão em volume (ppb (concentração típica ao meio do dia na estação chuvosa para valores em regiões fortemente impactadas por queimadas de até 100 ppb, nível que pode ser fitotóxico para a vegetação. O balanço de radiação é fortemente afetado, com uma perda líquida de até 70% da radiação fotossinteticamente ativa na superfície.The understanding of the natural processes that regulate atmospheric composition in Amazonia is critical to the establishment of a sustainable development strategy in the region. The large emissions of trace gases and aerosols during the dry season, as a result of biomass burning, profoundly change the composition of the atmosphere in most of its area. The concentration of trace gases and aerosols increases by a factor of 2 to 8 over large areas, affecting the natural mechanisms of

  3. Risk assessment of atmospheric emissions using machine learning

    Directory of Open Access Journals (Sweden)

    G. Cervone

    2008-09-01

    Full Text Available Supervised and unsupervised machine learning algorithms are used to perform statistical and logical analysis of several transport and dispersion model runs which simulate emissions from a fixed source under different atmospheric conditions.

    First, a clustering algorithm is used to automatically group the results of different transport and dispersion simulations according to specific cloud characteristics. Then, a symbolic classification algorithm is employed to find complex non-linear relationships between the meteorological input conditions and each cluster of clouds. The patterns discovered are provided in the form of probabilistic measures of contamination, thus suitable for result interpretation and dissemination.

    The learned patterns can be used for quick assessment of the areas at risk and of the fate of potentially hazardous contaminants released in the atmosphere.

  4. Volcano emissions of trace metals, atmospheric deposition, and supply to biogeochemical cycles

    Science.gov (United States)

    Hinkley, T.; Thornber, C. R.; Matsumoto, A.

    2003-12-01

    Quiescently degassing (not exploding) volcanoes inject into the troposphere plumes that have remarkably high concentrations of ordinarily-rare, volatile trace metals. In pre-industrial times, these emissions appear to have accounted for the strong "enrichments" (relative to concentrations in crustal material or in ocean solute) of many such trace metals in the material deposited from the atmosphere. This has been shown by measuring the source strength of the emissions of metals from volcanoes, and comparing that to the amounts of the metals (excess over amounts accounted for by rock dust and sea salt) deposited onto high-latitude ice sheets: volcano degassing outputs of metals and deposition masses of metals to ice are comparable, on the basis of the masses (fluxes) and proportions of the metals, and from the proportions of lead (Pb) isotopes. There is indication that in modern industrial times the elevated trace metal fractions in the atmospheric material that has small particle size and long atmospheric residence time is still more strongly influenced by volcano emissions than by industrial emissions. Throughout earth's history it is likely that volcano emissions were a major control on the environmental background levels of trace elements, in which plants and animals evolved their tolerances to these mostly-poisonous substances.

  5. Ground-Based Observations of Unusual Atmospheric Light Emissions

    Institute of Scientific and Technical Information of China (English)

    杨静; 陆高鹏; 杜艰; 潘蔚琳

    2014-01-01

    Unusual atmospheric light emissions were observed from a station located in Shandong Province of East China. The main morphology of these events includes a bright glowing spot, which differs distinctly from any type of transient luminous events (TLEs) well recognized in literature, such as sprites, halos, elves, gigantic jets, blue jets, and blue starters. A comparison between the observations of four such light emission events and the data from lightning detection networks reveals no correlation between these events and the intense lightning activity in the adjacent area. The events reported in this paper may imply the existence of a new phenomenon with a mechanism that remains to be investigated with further observation and complementary lightning measurement.

  6. Atmospheric transport and deposition of Indonesian volcanic emissions

    Directory of Open Access Journals (Sweden)

    M. A. Pfeffer

    2005-11-01

    Full Text Available A regional climate model study has been performed to investigate the transport and atmospheric loss rates of emissions from Indonesian volcanoes and the sensitivity of these emissions to meteorological conditions and the solubility of the released emissions. Two experiments were conducted: 1 volcanic sulfur released as primarily SO2 and oxidation to SO42− determined by considering the major tropospheric chemical reactions; and 2 PbCl2 released as an infinitely soluble passive tracer. The first experiment was used to calculate SO2 loss rates from each active volcano resulting in an annual mean loss rate for all volcanoes of 1.1×10−5 s−1, or an e-folding rate of approximately 1 day. SO2 loss rate was found to vary seasonally, be poorly correlated with wind speed, and uncorrelated with temperature or relative humidity. The variability of SO2 loss rates is found to be correlated with the variability of wind speeds, suggesting that it is much more difficult to establish a ''typical'' SO2 loss rate for volcanoes that are exposed to inconsistent winds. Within an average distance of 69 km away from the active Indonesian volcanoes, 53% of SO2 is lost due to conversion to SO42−, 42% due to dry deposition, and 5% is lost due to lateral transport away from the dominant direction of plume travel. The solubility of volcanic emissions in water is shown to have a major influence on their atmospheric transport and deposition. High concentrations of PbCl2 are predicted to be deposited near to the volcanoes while volcanic S travels further away until removal from the atmosphere primarily via the wet deposition of H2SO4. The ratio of the concentration of PbCl2 to SO2 is found to exponentially decay at increasing distance from the volcanoes

  7. Impact of aircraft emissions on the atmospheric chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Dameris, M.; Sausen, R.; Grewe, V.; Koehler, I.; Ponater, M. [Deutsche Forschungs- und Versuchsanstalt fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere; Steil, B. [Max-Planck-Inst. fuer Meteorologie, Hamburg (Germany); Bruehl, Ch. [Max-Planck-Inst. fuer Chemie (Otto-Hahn-Institut), Mainz (Germany)

    1997-12-31

    A hierarchy of models of different complexity has been applied to estimate the impact of aircraft NO{sub x} emissions on atmospheric chemistry. The global circulation model ECHAM3 has been coupled with two types of chemistry modules. The first of these describes only a simplified (linear) NO{sub x} and HNO{sub 3} chemistry while the second one is a comprehensive chemistry module (CHEM), describing tropospheric and stratospheric chemistry including photochemical reactions and heterogeneous reactions on sulphate aerosols and PSCs. The module CHEM has been coupled either off-line or with feedback via the ozone concentration. First results of multilayer integrations (over decades) are discussed. (author) 27 refs.

  8. Environmental control technology for atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, M; Albanese, A S

    1980-01-01

    The impact of fossil fuel use in the United States on worldwide CO/sub 2/ emissions and the impact of increased coal utilization on CO/sub 2/ emission rates are assessed. The aspects of CO/sub 2/ control are discussed as well as the available CO/sub 2/ control points (CO/sub 2/ removal sites). Two control scenarios are evaluated, one based on the absorption of CO/sub 2/ contained in power plant flue gas by seawater; the other, based on absorption of CO/sub 2/ by MEA (Mono Ethanol Amine). Captured CO/sub 2/ is injected into the deep ocean in both cases. The analyses indicate that capture and disposal by seawater is energetically not feasible, whereas capture and disposal using MEA is a possibility. However, the economic penalities of CO/sub 2/ control are significant. The use of non-fossil energy sources, such as hydroelectric, nuclear or solar energy is considered as an alternative for limiting and controlling CO/sub 2/ emissions resulting from fossil energy usage.

  9. Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET)

    International Nuclear Information System (INIS)

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses that individuals may have received from operations at the Hanford Site since 1944. This report deals specifically with the atmospheric transport model, Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). RATCHET is a major rework of the MESOILT2 model used in the first phase of the HEDR Project; only the bookkeeping framework escaped major changes. Changes to the code include (1) significant changes in the representation of atmospheric processes and (2) incorporation of Monte Carlo methods for representing uncertainty in input data, model parameters, and coefficients. To a large extent, the revisions to the model are based on recommendations of a peer working group that met in March 1991. Technical bases for other portions of the atmospheric transport model are addressed in two other documents. This report has three major sections: a description of the model, a user's guide, and a programmer's guide. These sections discuss RATCHET from three different perspectives. The first provides a technical description of the code with emphasis on details such as the representation of the model domain, the data required by the model, and the equations used to make the model calculations. The technical description is followed by a user's guide to the model with emphasis on running the code. The user's guide contains information about the model input and output. The third section is a programmer's guide to the code. It discusses the hardware and software required to run the code. The programmer's guide also discusses program structure and each of the program elements

  10. Exoplanet atmosphere. Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy.

    Science.gov (United States)

    Stevenson, Kevin B; Désert, Jean-Michel; Line, Michael R; Bean, Jacob L; Fortney, Jonathan J; Showman, Adam P; Kataria, Tiffany; Kreidberg, Laura; McCullough, Peter R; Henry, Gregory W; Charbonneau, David; Burrows, Adam; Seager, Sara; Madhusudhan, Nikku; Williamson, Michael H; Homeier, Derek

    2014-11-14

    Exoplanets that orbit close to their host stars are much more highly irradiated than their solar system counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase ("phase-curve observations") for the highly irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet's atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure at all longitudes. We also derive a Bond albedo of 0.18(-0.12)(+0.07) and an altitude dependence in the hot-spot offset relative to the substellar point.

  11. Puff models for simulation of fugitive radioactive emissions in atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Camila P. da, E-mail: camila.costa@ufpel.edu.b [Universidade Federal de Pelotas (UFPel), RS (Brazil). Inst. de Fisica e Matematica. Dept. de Matematica e Estatistica; Pereira, Ledina L., E-mail: ledinalentz@yahoo.com.b [Universidade do Extremo Sul Catarinense (UNESC), Criciuma, SC (Brazil); Vilhena, Marco T., E-mail: vilhena@pq.cnpq.b [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Tirabassi, Tiziano, E-mail: t.tirabassi@isac.cnr.i [Institute of Atmospheric Sciences and Climate (CNR/ISAC), Bologna (Italy)

    2009-07-01

    A puff model for the dispersion of material from fugitive radioactive emissions is presented. For vertical diffusion the model is based on general techniques for solving time dependent advection-diffusion equation: the ADMM (Advection Diffusion Multilayer Method) and GILTT (Generalized Integral Laplace Transform Technique) techniques. The first one is an analytical solution based on a discretization of the Atmospheric Boundary Layer (ABL) in sub-layers where the advection-diffusion equation is solved by the Laplace transform technique. The solution is given in integral form. The second one is a well-known hybrid method that had solved a wide class of direct and inverse problems mainly in the area of Heat Transfer and Fluid Mechanics and the solution is given in series form. Comparisons between values predicted by the models against experimental ground-level concentrations are shown. (author)

  12. Evidence of atmospheric nanoparticle formation from emissions of marine microorganisms

    Science.gov (United States)

    Sellegri, K.; Pey, J.; Rose, C.; Culot, A.; DeWitt, H. L.; Mas, S.; Schwier, A. N.; Temime-Roussel, B.; Charriere, B.; Saiz-Lopez, A.; Mahajan, A. S.; Parin, D.; Kukui, A.; Sempere, R.; D'Anna, B.; Marchand, N.

    2016-06-01

    Earth, as a whole, can be considered as a living organism emitting gases and particles into its atmosphere, in order to regulate its own temperature. In particular, oceans may respond to climate change by emitting particles that ultimately will influence cloud coverage. At the global scale, a large fraction of the aerosol number concentration is formed by nucleation of gas-phase species, but this process has never been directly observed above oceans. Here we present, using semicontrolled seawater-air enclosures, evidence that nucleation may occur from marine biological emissions in the atmosphere of the open ocean. We identify iodine-containing species as major precursors for new particle clusters' formation, while questioning the role of the commonly accepted dimethyl sulfide oxidation products, in forming new particle clusters in the region investigated and within a time scale on the order of an hour. We further show that amines would sustain the new particle formation process by growing the new clusters to larger sizes. Our results suggest that iodine-containing species and amines are correlated to different biological tracers. These observations, if generalized, would call for a substantial change of modeling approaches of the sea-to-air interactions.

  13. Fossil fuel consumption and heavy metal emissions into the atmosphere in Russia

    International Nuclear Information System (INIS)

    In recent decades more and more attention has been paid to the problem of ecosystem pollution by heavy metals. Many trace elements are registered now as a global pollutant due to their toxic nature. Their negative influence on the environment is caused by accumulation in different ecosystem components and increased involvement in biochemical cycles. The atmosphere is the main medium through which pollutants transported from emission sources to background territories where heavy metals are deposited into water and on plants. Heavy metal emissions into the atmosphere cause certain global environmental problems due to their long lifetime and the long-term transport of these elements in the atmosphere, as well as the increasing rate of their accumulation in the environment even at most remote territories. Moreover, heavy metals have evidently entered human food chains. The influence of global ecosystem pollution by heavy metals on human health is not well known as yet. Most trace elements comes into the atmosphere with natural and man-made aerosols. The main sources of natural aerosols in the atmosphere are soil erosion and weathering of mountain rocks, volcanic and space dust, forest firing smoke, and others. Major anthropogenic sources of toxic elements are fossil fuel combustion, mining, industrial processes, and waste incineration. The anthropogenic flow of heavy metals to the atmosphere is about 94-97 per cent of the total. An inventory of emission sources should be the first step in developing a control strategy and modelling global and regional cycles of trace elements. In this article the situation with lead, cadmium and mercury emissions from coal combustion of power plants and gasoline combustion by road transport is discussed. Pollutant amounts released into the atmosphere in industrial regions induce not only local deterioration of air, but they also affect on remote areas, and areas sensitive to contamination, such as the Arctic region. Problems on the

  14. Sulfur Dioxide Emission Control, Blockade and Drainage

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper presents the present status of sulfur dioxide emission from thermal plants in China, tells the main problems existing in its emission control and finally gives out suggestions to the problems, that is, to constitute complete standards and regulations and enhancesupervision accordingly.

  15. Evaporation Controlled Emission in Ventilated Rooms

    DEFF Research Database (Denmark)

    Topp, Claus; Nielsen, Peter V.; Heiselberg, Per

    -scale ventilated room when the emission is fully or partly evaporation controlled. The objective of the present research work has been to investigate the change of emission rates from small-scale experiments to full-scale ventilated rooms and to investigate the influence of the local air velocity field near...

  16. Variable emissivity laser thermal control system

    Science.gov (United States)

    Milner, Joseph R.

    1994-01-01

    A laser thermal control system for a metal vapor laser maintains the wall mperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser.

  17. Constraining atmospheric ammonia emissions through new observations with an open-path, laser-based sensor

    Science.gov (United States)

    Sun, Kang

    As the third most abundant nitrogen species in the atmosphere, ammonia (NH3) is a key component of the global nitrogen cycle. Since the industrial revolution, humans have more than doubled the emissions of NH3 to the atmosphere by industrial nitrogen fixation, revolutionizing agricultural practices, and burning fossil fuels. NH3 is a major precursor to fine particulate matter (PM2.5), which has adverse impacts on air quality and human health. The direct and indirect aerosol radiative forcings currently constitute the largest uncertainties for future climate change predictions. Gas and particle phase NH3 eventually deposits back to the Earth's surface as reactive nitrogen, leading to the exceedance of ecosystem critical loads and perturbation of ecosystem productivity. Large uncertainties still remain in estimating the magnitude and spatiotemporal patterns of NH3 emissions from all sources and over a range of scales. These uncertainties in emissions also propagate to the deposition of reactive nitrogen. To improve our understanding of NH3 emissions, observational constraints are needed from local to global scales. The first part of this thesis is to provide quality-controlled, reliable NH3 measurements in the field using an open-path, quantum cascade laser-based NH3 sensor. As the second and third part of my research, NH3 emissions were quantified from a cattle feedlot using eddy covariance (EC) flux measurements, and the similarities between NH3 turbulent fluxes and those of other scalars (temperature, water vapor, and CO2) were investigated. The fourth part involves applying a mobile laboratory equipped with the open-path NH3 sensor and other important chemical/meteorological measurements to quantify fleet-integrated NH3 emissions from on-road vehicles. In the fifth part, the on-road measurements were extended to multiple major urban areas in both the US and China in the context of five observation campaigns. The results significantly improved current urban NH3

  18. Atmospheric Cloud Physics Laboratory thermal control

    Science.gov (United States)

    Moses, J. L.; Fogal, G. L.; Scollon, T. R., Jr.

    1978-01-01

    The paper presents the development background and the present status of the Atmospheric Cloud Physics Laboratory (ACPL) thermal control capability. The ACPL, a Spacelab payload, is currently in the initial flight hardware development phase for a first flight scheduled in June 1981. The ACPL is intended as a facility for conducting a wide variety of cloud microphysics experimentation under zero gravity conditions. The cloud chambers, which are key elements of the ACPL, have stringent thermal requirements. Thus the expansion chamber inner walls must be uniform to within + or - 0.1 C during both steady-state and transient operation over a temperature range of +30 to -25 C. Design progression of the expansion chamber, from early in-house NASA-MSFC concepts (including test results of a prototype chamber) to a thermal control concept currently under development, is discussed.

  19. Efficiency and Sensitivity Analysis of Observation Networks for Atmospheric Inverse Modelling with Emissions

    CERN Document Server

    Wu, Xueran; Jacob, Birgit

    2015-01-01

    The controllability of advection-diffusion systems, subject to uncertain initial values and emission rates, is estimated, given sparse and error affected observations of prognostic state variables. In predictive geophysical model systems, like atmospheric chemistry simulations, different parameter families influence the temporal evolution of the system.This renders initial-value-only optimisation by traditional data assimilation methods as insufficient. In this paper, a quantitative assessment method on validation of measurement configurations to optimize initial values and emission rates, and how to balance them, is introduced. In this theoretical approach, Kalman filter and smoother and their ensemble based versions are combined with a singular value decomposition, to evaluate the potential improvement associated with specific observational network configurations. Further, with the same singular vector analysis for the efficiency of observations, their sensitivity to model control can be identified by deter...

  20. The Ademe research programme on atmospheric emissions from composting. Research findings and literature review - final report

    International Nuclear Information System (INIS)

    sites), of their dispersion to the atmosphere and subsequent exposure to the local population. Following on from this programme, a compilation of the results produced, drawing also from a literature review, has been undertaken and is presented here. This scientific work, written by the research partners of the programme, draws from both their expertise and gained experience. It can thus be considered a 'state of the art' of the current understanding of atmospheric emissions from composting: be it emission values, means of measurement or of their control. The document is organized in three main parts: In the first, the general principles of composting and the related atmospheric emissions are given. The section also sets out the current understanding of the main impacts on the environment and on the health of staff and people living near the composting sites. The second part is deals with the quantification of the emissions. It describes the methods and strategies of sampling and analysis for gas emissions (including odors) and for particulates (including micro-organisms). The quantitative emission data provided in this section are current figures taken from reference documents already produced by ADEME. These values are brought up to date with data taken from international scientific literature and from the results of the research programme on the emissions from composting. The current report takes note in particular of the knowledge of factors affecting emission. The section then sets out the dispersion of the gaseous emissions and particulates around the site. It brings in modelling and the concept of background noise, essential in the interpretation of the results from measurement campaigns of the environment around compost sites. The third part looks at the consequences of the work given in the report. This includes especially recommendations for the prevention of emissions and for the direction of future studies. The outlook for future and related research is also

  1. Mapping the spatial distribution of global anthropogenic mercury atmospheric emission inventories

    NARCIS (Netherlands)

    Wilson, Simon J.; Steenhuisen, Frits; Pacyna, Jozef M.; Pacyna, Elisabeth G.

    2006-01-01

    This paper describes the procedures employed to spatially distribute global inventories of anthropogenic emissions of mercury to the atmosphere, prepared by Pacyna, E.G., Pacyna, J.M., Steenhuisen, F., Wilson, S. [2006. Global anthropogenic mercury emission inventory for 2000. Atmospheric Environmen

  2. Estimating global natural wetland methane emissions using process modelling: spatio-temporal patterns and contributions to atmospheric methane fluctuations

    Science.gov (United States)

    Zhu, Qiuan; Peng, Changhui; Chen, Huai; Fang, Xiuqin; Liu, Jinxun; Jiang, Hong; Yang, Yanzheng; Yang, Gang

    2015-01-01

    Aim The fluctuations of atmospheric methane (CH4) that have occurred in recent decades are not fully understood, particularly with regard to the contribution from wetlands. The application of spatially explicit parameters has been suggested as an effective method for reducing uncertainties in bottom-up approaches to wetland CH4 emissions, but has not been included in recent studies. Our goal was to estimate spatio-temporal patterns of global wetland CH4 emissions using a process model and then to identify the contribution of wetland emissions to atmospheric CH4fluctuations. Location Global. Methods A process-based model integrated with full descriptions of methanogenesis (TRIPLEX-GHG) was used to simulate global wetland CH4emissions. Results Global annual wetland CH4 emissions ranged from 209 to 245 Tg CH4 year−1 between 1901 and 2012, with peaks occurring in 1991 and 2012. There is a decreasing trend between 1990 and 2010 with a rate of approximately 0.48 Tg CH4 year−1, which was largely caused by emissions from tropical wetlands showing a decreasing trend of 0.44 Tg CH4 year−1 since the 1970s. Emissions from tropical, temperate and high-latitude wetlands comprised 59, 26 and 15% of global emissions, respectively. Main conclusion Global wetland CH4 emissions, the interannual variability of which was primary controlled by tropical wetlands, partially drive the atmosphericCH4 burden. The stable to decreasing trend in wetland CH4 emissions, a result of a balance of emissions from tropical and extratropical wetlands, was a particular factor in slowing the atmospheric CH4 growth rate during the 1990s. The rapid decrease in tropical wetland CH4emissions that began in 2000 was supposed to offset the increase in anthropogenic emissions and resulted in a relatively stable level of atmospheric CH4 from 2000 to 2006. Increasing wetland CH4 emissions, particularly after 2010, should be an important contributor to the growth in

  3. Io control of Jovian radio emission

    Science.gov (United States)

    Desch, M. D.

    1980-01-01

    The possibility of Io controlling Jovian decametric radio emission, particularly in the region below 22 MHz, is discussed. Results of a two-year survey at 26.3 at 26.3 MHz are presented which demonstrate the control of Io over a high-intensity storm component of the radio emission and the independence of a weak radio component from the phase of Io, as was observed at lower frequencies. It is thus hypothesized that Io control is a flux-dependent rather than a frequency-dependent phenomenon, and results of analyses at 18 and 10 MHz which support this hypothesis are presented. The apparent correlation between frequency and Io control is thus shown to result from a selection effect due to the increase of non-Io emission with decreasing frequency and relative antenna detection threshold. This result implies a contiguous Io-controlled source region extending out several Jovian radii along the Io flux tube.

  4. Regulation of radionuclides discharges to the atmosphere and emissions to the water from Ukraine NPPs

    International Nuclear Information System (INIS)

    The possible order of radionuclides discharges to the atmosphere and emissions to the water from Ukraine NPPs regulation is given allowance for laws and norms of Ukraine and ICRP and IAEA guidelines. For definition of a dose relevant to marginal discharges to the atmosphere and emissions to the water of separate radionuclides are counted dose coefficients (Sv/Bg). Considered three critical age groups: the babies (up to 1 year), children (till 10 years) and adult. The age group being critical for discharges to the atmosphere and emissions to the water are determined. The radionuclides producing the greatest contribution to a dose are determined. Guidelines on calculation of marginal radionuclides discharges to the atmosphere and emissions to the water of Ukraine NPPs are given. Matching of doses from actual radionuclides discharges to the atmosphere and emissions to the water of Ukraine NPPs with quotas, assigned in RSNU-97 is carried out

  5. Control of Jovian Radio Emission by Callisto

    Science.gov (United States)

    Menietti, J. D.; Gurnett, D. A.; Christopher, I.

    2001-01-01

    Galileo has been in orbit around Jupiter since December 1995 and a large database has been collected. We present the results of a survey of the plasma wave data for the frequency range 2.0 MHz to 5.6 MHz, the low frequency decametric (DAM) emissions. While the control of a portion of the radio emission by the moon lo is well known, and Ganymede control has been more recently indicated, we report that a small but significant portion of DAM emission is seen to be correlated with the orbital phase of Callisto. While the occurrence rate of emission controlled by Ganymede and Callisto is considerably less than for lo, the power levels can be nearly the same. We estimate the power of the Callisto-dependent emission to be approx. 70% of the Io-dependent radio emission and about the same as the Ganymede-dependent radio emission. This result indicates an Alfven current system associated with Callisto, and thus a significant interaction of the magnetosphere of Callisto with that of Jupiter as is believed to exist for both lo and Ganymede.

  6. Atmospheric emissions from a passenger ferry with selective catalytic reduction.

    Science.gov (United States)

    Nuszkowski, John; Clark, Nigel N; Spencer, Thomas K; Carder, Daniel K; Gautam, Mridul; Balon, Thomas H; Moynihan, Paul J

    2009-01-01

    The two main propulsion engines on Staten Island Ferry Alice Austen (Caterpillar 3516A, 1550 hp each) were fitted with selective catalytic reduction (SCR) aftertreatment technology to reduce emissions of oxides of nitrogen (NOx). After the installation of the SCR system, emissions from the ferry were characterized both pre- and post-aftertreatment. Prior research has shown that the ferry operates in four modes, namely idle, acceleration, cruise, and maneuvering modes. Emissions were measured for both engines (designated NY and SI) and for travel in both directions between Manhattan and Staten Island. The emissions characterization used an analyzer system, a data logger, and a filter-based particulate matter (PM) measurement system. The measurement of NOx, carbon monoxide (CO), and carbon dioxide (CO2) were based on federal reference methods. With the existing control strategy for the SCR urea injection, the SCR provided approximately 64% reduction of NOx for engine NY and 36% reduction for engine SI for a complete round trip with less than 6.5 parts per million by volume (ppmv) of ammonia slip during urea injection. Average reductions during the cruise mode were 75% for engine NY and 47% for engine SI, which was operating differently than engine NY. Reductions for the cruise mode during urea injection typically exceeded 94% from both engines, but urea was injected only when the catalyst temperature reached a 300 degrees C threshold pre- and postcatalyst. Data analysis showed a total NOx mass emission split with 80% produced during cruise, and the remaining 20% spread across idle, acceleration, and maneuvering. Examination of continuous NOx data showed that higher reductions of NOx could be achieved on both engines by initiating the urea injection at an earlier point (lower exhaust temperature) in the acceleration and cruise modes of operation. The oxidation catalyst reduced the CO production 94% for engine NY and 82% for engine SI, although the high CO levels

  7. Are biogenic emissions a significant source of summertime atmospheric toluene in rural Northeastern United States?

    Directory of Open Access Journals (Sweden)

    M. L. White

    2008-06-01

    Full Text Available Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequentially, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004–2006. These included: 1 increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG content to meet U.S. EPA summertime volatility standards, 2 local industrial emissions and 3 local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d−1, and did not fully account for the observed enhancements (20–50 pptv in 2004–2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d−1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d−1 and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  8. Are biogenic emissions a significant source of summertime atmospheric toluene in the rural Northeastern United States?

    Directory of Open Access Journals (Sweden)

    M. L. White

    2009-01-01

    Full Text Available Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequently, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004–2006. These included: (1 increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG content to meet US EPA summertime volatility standards, (2 local industrial emissions and (3 local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d−1, and did not fully account for the observed enhancements (20–50 pptv in 2004–2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d−1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d−1 and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  9. Economic growth and carbon emission control

    Science.gov (United States)

    Zhang, Zhenyu

    The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal

  10. COMPOSITIVE EMISSION CONTROL SYSTEM OF GASOLINE VEHICLE

    Institute of Scientific and Technical Information of China (English)

    CAI Ruibin; CHEN Zijian

    2006-01-01

    The working principle of a kind of compositive emission control system is inquired into,which includes exhaust heater, secondary air supplement, exhaust gas recirculation (EGR), thermal reactor and catalytic converter, etc. The purification effect of CO, HC and NOx emission of the gasoline spark ignite (S.I.) engine is studied. The entire vehicle driving cycle tests based on the national emission standard and a series of the gasoline engine-testing bench tests including full load characteristic experiment, load characteristic experiment and idle speed experiment are done. The results show that the system has a very good emission control effect to CO, HC and NOx of gasoline engine. The construction of the system is very simple and can be mounted on the exhaust pipe conveniently without any alteration of the vehicle-use gasoline engine.

  11. Gaseous emissions from plants in controlled environments

    Science.gov (United States)

    Dubay, Denis T.

    1988-01-01

    Plant growth in a controlled ecological life support system may entail the build-up over extended time periods of phytotoxic concentrations of volatile organic compounds produced by the plants themselves. Ethylene is a prominent gaseous emission of plants, and is the focus of this report. The objective was to determine the rate of ethylene release by spring wheat, white potato, and lettuce during early, middle, and late growth stages, and during both the light and dark segments of the diurnal cycle. Plants grown hydroponically using the nutrient film technique were covered with plexiglass containers for 4 to 6 h. At intervals after enclosure, gas samples were withdrawn with a syringe and analyzed for ethylene with a gas chromatograph. Lettuce produced 10 to 100 times more ethylene than wheat or potato, with production rates ranging from 141 to 158 ng g-dry/wt/h. Wheat produced from 1.7 to 14.3 ng g-dry/wt/h, with senescent wheat producing the least amount and flowering wheat the most. Potatoes produced the least amount of ethylene, with values never exceeding 5 ng g-dry/wt/h. Lettuce and potatoes each produced ethylene at similar rates whether in dark period or light period. Ethylene sequestering of 33 to 43 percent by the plexiglass enclosures indicated that these production estimates may be low by one-third to one-half. These results suggest that concern for ethylene build-up in a contained atmosphere should be greatest when growing lettuce, and less when growing wheat or potato.

  12. Control of Jovian Radio Emission by Ganymede

    Science.gov (United States)

    Menietti, J. D.; Gurnett, D. A.; Kurth, W. S.; Groene, J. B.

    1998-01-01

    Galileo has been in orbit around Jupiter since December 1995. We present the results of a survey of the data for the frequency range 3.2 MHz to 5.6 MHz, the low-frequency decametric (DAM) emissions. While the control of a portion of the radio emission by the moon Io is well-known, we report that a small but significant portion of low-frequency DAM emission is seen to be correlated with the orbital phase of Ganymede. This result is in agreement with other recent results indicating a significant interaction of the magnetosphere of Ganymede with that of Jupiter.

  13. Holistic control of ship noise emissions

    OpenAIRE

    Borelli Davide; Gaggero Tomaso; Rizzuto Enrico; Schenone Corrado

    2016-01-01

    The sustainability of anthropogenic activities at sea is recently gaining more and more attention. As regards shipping, emissions from ships into the environment of various nature (engine exhaust gases, anti-fouling paints leaching, ballast exchange, releases at sea of oil and other noxious liquid or solid cargoes, of sewage and of garbage) have been recognized as sources of pollution and therefore controlled and limited since a long time. The subject of noise emission...

  14. Simultaneous physical retrieval of surface emissivity spectrum and atmospheric parameters from infrared atmospheric sounder interferometer spectral radiances.

    Science.gov (United States)

    Masiello, Guido; Serio, Carmine

    2013-04-10

    The problem of simultaneous physical retrieval of surface emissivity, skin temperature, and temperature, water-vapor, and ozone atmospheric profiles from high-spectral-resolution observations in the infrared is formulated according to an inverse problem with multiple regularization parameters. A methodology has been set up, which seeks an effective solution to the inverse problem in a generalized L-curve criterion framework. The a priori information for the surface emissivity is obtained on the basis of laboratory data alone, and that for the atmospheric parameters by climatology or weather forecasts. To ensure that we deal with a problem of fewer unknowns than observations, the dimensionality of the emissivity is reduced through expansion in Fourier series. The main objective of this study is to demonstrate the simultaneous retrieval of emissivity, skin temperature, and atmospheric parameters with a two-dimensional L-curve criterion. The procedure has been demonstrated with spectra observed from the infrared atmospheric sounder interferometer, flying onboard the European Meteorological Operational satellite. To check the quality and reliability of the methodology, we have used spectra recorded over regions characterized by known or stable emissivity. These include sea surface, for which effective emissivity models are known, and arid lands (Sahara and Namib Deserts) that are known to exhibit the characteristic spectral signature of quartz-rich sand.

  15. Simultaneous physical retrieval of surface emissivity spectrum and atmospheric parameters from infrared atmospheric sounder interferometer spectral radiances.

    Science.gov (United States)

    Masiello, Guido; Serio, Carmine

    2013-04-10

    The problem of simultaneous physical retrieval of surface emissivity, skin temperature, and temperature, water-vapor, and ozone atmospheric profiles from high-spectral-resolution observations in the infrared is formulated according to an inverse problem with multiple regularization parameters. A methodology has been set up, which seeks an effective solution to the inverse problem in a generalized L-curve criterion framework. The a priori information for the surface emissivity is obtained on the basis of laboratory data alone, and that for the atmospheric parameters by climatology or weather forecasts. To ensure that we deal with a problem of fewer unknowns than observations, the dimensionality of the emissivity is reduced through expansion in Fourier series. The main objective of this study is to demonstrate the simultaneous retrieval of emissivity, skin temperature, and atmospheric parameters with a two-dimensional L-curve criterion. The procedure has been demonstrated with spectra observed from the infrared atmospheric sounder interferometer, flying onboard the European Meteorological Operational satellite. To check the quality and reliability of the methodology, we have used spectra recorded over regions characterized by known or stable emissivity. These include sea surface, for which effective emissivity models are known, and arid lands (Sahara and Namib Deserts) that are known to exhibit the characteristic spectral signature of quartz-rich sand. PMID:23670773

  16. The effects of energy paths and emission controls and standards on future trends in China's emissions of primary air pollutants

    Science.gov (United States)

    Zhao, Y.; Zhang, J.; Nielsen, C. P.

    2014-09-01

    To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission trends for all the concerned pollutants. As recently promulgated national action plans of air pollution prevention and control (NAPAPPC) are implemented, China's anthropogenic pollutant emissions should decline. For example, the emissions of SO2, NOx, total suspended particles (TSP), PM10, and PM2.5 are estimated to decline 7, 20, 41, 34, and 31% from 2010 to 2030, respectively, in the "best guess" scenario that includes national commitment of energy saving policy and implementation of NAPAPPC. Should the issued/proposed emission standards be fully achieved, a less likely scenario, annual emissions would be further reduced, ranging from 17 (for primary PM2.5) to 29% (for NOx) declines in 2015, and the analogue numbers would be 12 and 24% in 2030. The uncertainties of emission projections result mainly from the uncertain operational conditions of swiftly proliferating air pollutant control devices and lack of detailed information about emission control plans by region. The predicted emission trends by sector and chemical species raise concerns about current pollution control strategies: the potential for emissions abatement in key sectors may be declining due to the near saturation of emission control devices use; risks of ecosystem acidification could rise because emissions of alkaline base cations may be declining faster than those of SO2; and radiative forcing could rise because emissions of positive-forcing carbonaceous aerosols may decline more slowly than those of SO2 emissions and thereby

  17. Jovian longitudinal control of Io-related radio emissions

    Energy Technology Data Exchange (ETDEWEB)

    Dessler, A.J.; Hill, T.W.

    1979-01-15

    We propose a theoretical model to explain the control that Jupiter's rotational phase exercizes over Io-related radio emissions. Longitudinal asymmetries in the conductivity and electron content of Jupiter's ionosphere are generated by variations in the mirror altitudes of energetic electrons trapped in Jupiter's magnetosphere. Energetic electrons are absorbed by the atmosphere preferentially in regions where, because of higher-order magnetic moments, the low-altitude magnetic field strength, and hence the mirror altitude of trapped particles, is a decreasing function of Jovian longitude. In such regions, the lower edge of the trapped radiation is lost into the atmosphere, and the resulting electron-impact ionization causes an increase in both the conductivity and the charged particle content of the ionosphere. When the flux tube threading Io passes into such regions of weakening surface magnetic field (specifically, a negative longitudinal gradient), a low-pressure electric arc can be struck in Jupiter's atmosphere that results in enhancement of the Birkeland (magnetically field-aligned) current between Io and the Jovian ionosphere. Thus Io excites detectable low-frequency (dekametric) radio emission when its flux tube encounters a relative weakening of the magnetic field strength at its foot. The location of the principal negative longitudinal gradient in the surface field strenght, as extrapolated from the Pioneer 11 flyby, is in reasonable accord with the longitude of the ionospheric region from which the principal Io-related emissions are observed to arise.

  18. Nanophotonic control of circular dipole emission.

    Science.gov (United States)

    le Feber, B; Rotenberg, N; Kuipers, L

    2015-01-01

    Controlling photon emission by single emitters with nanostructures is crucial for scalable on-chip information processing. Nowadays, nanoresonators can affect the lifetime of linear dipole emitters, while nanoantennas can steer the emission direction. Expanding this control to the emission of orbital angular momentum-changing transitions would enable a future coupling between solid state and photonic qubits. As these transitions are associated with circular dipoles, such control requires knowledge of the interaction of a complex dipole with optical eigenstates containing local helicity. We experimentally map the coupling of classical, circular dipoles to photonic modes in a photonic crystal waveguide. We show that, depending on the combination of the local helicity of the mode and the dipole helicity, circular dipoles can couple to left- or rightwards propagating modes with a near-unity directionality. The experimental maps are in excellent agreement with calculations. Our measurements, therefore, demonstrate the possibility of coupling the spin to photonic pathway. PMID:25833305

  19. Advanced CIDI Emission Control System Development

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, Christine

    2006-05-31

    Ford Motor Company, with ExxonMobil and FEV, participated in the Department of Energy's (DOE) Ultra-Clean Transportation Fuels Program with the goal to develop an innovative emission control system for light-duty diesel vehicles. The focus on diesel engine emissions was a direct result of the improved volumetric fuel economy (up to 50%) and lower CO2 emissions (up to 25%) over comparable gasoline engines shown in Europe. Selective Catalytic Reduction (SCR) with aqueous urea as the NOx reductant and a Catalyzed Diesel Particulate Filter (CDPF) were chosen as the primary emission control system components. The program expected to demonstrate more than 90% durable reduction in particulate matter (PM) and NOx emissions on a light-duty truck application, based on the FTP-75 drive cycle. Very low sulfur diesel fuel (<15 ppm-wt) enabled lower PM emissions, reduced fuel economy penalty due to the emission control system and improved long-term system durability. Significant progress was made toward a durable system to meet Tier 2 Bin 5 emission standards on a 6000 lbs light-duty truck. A 40% reduction in engine-out NOx emissions was achieved with a mid-size prototype diesel engine through engine recalibration and increased exhaust gas recirculation. Use of a rapid warm-up strategy and urea SCR provided over 90% further NOx reduction while the CDPF reduced tailpipe PM to gasoline vehicle levels. Development work was conducted to separately improve urea SCR and CDPF system durability, as well as improved oxidation catalyst function. Exhaust gas NOx and ammonia sensors were also developed further. While the final emission control system did not meet Tier 2 Bin 5 NOx after 120k mi of aging on the dynamometer, it did meet the standards for HC, NMOG, and PM, and an improved SCR catalyst was shown to have potential to meet the NOx standard, assuming the DOC durability could be improved further. Models of DOC and SCR function were developed to guide the study of several key

  20. Estimation of mercury emission from different sources to atmosphere in Chongqing, China.

    Science.gov (United States)

    Wang, Dingyong; He, Lei; Wei, Shiqiang; Feng, Xinbin

    2006-08-01

    This investigation presents a first assessment of the contribution to the regional mercury budget from anthropogenic and natural sources in Chongqing, an important industrial region in southwest China. The emissions of mercury to atmosphere from anthropogenic sources in the region were estimated through indirect approaches, i.e. using commonly acceptable emission factors method, which based on annual process throughputs or consumption for these sources. The natural mercury emissions were estimated from selected natural sources by the dynamic flux chamber technique. The results indicated that the anthropogenic mercury emissions totaled approximately 8.85 tons (t), more than 50% of this total originated in coal combustion and 23.7% of this total emission in the industrial process (include cement production, metal smelting and chemical industry). The natural emissions represented approximately 17% of total emissions (1.78 t yr(-1)). The total mercury emission to atmosphere in Chongqing in 2001 was 10.63 t. PMID:16219340

  1. Atmospheric three-dimensional inverse modeling of regional industrial emissions and global oceanic uptake of carbon tetrachloride

    Science.gov (United States)

    Xiao, X.; Prinn, R. G.; Fraser, P. J.; Weiss, R. F.; Simmonds, P. G.; O'Doherty, S.; Miller, B. R.; Salameh, P. K.; Harth, C. M.; Krummel, P. B.; Golombek, A.; Porter, L. W.; Butler, J. H.; Elkins, J. W.; Dutton, G. S.; Hall, B. D.; Steele, L. P.; Wang, R. H. J.; Cunnold, D. M.

    2010-11-01

    Carbon tetrachloride (CCl4) has substantial stratospheric ozone depletion potential and its consumption is controlled under the Montreal Protocol and its amendments. We implement a Kalman filter using atmospheric CCl4 measurements and a 3-dimensional chemical transport model to estimate the interannual regional industrial emissions and seasonal global oceanic uptake of CCl4 for the period of 1996-2004. The Model of Atmospheric Transport and Chemistry (MATCH), driven by offline National Center for Environmental Prediction (NCEP) reanalysis meteorological fields, is used to simulate CCl4 mole fractions and calculate their sensitivities to regional sources and sinks using a finite difference approach. High frequency observations from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Earth System Research Laboratory (ESRL) of the National Oceanic and Atmospheric Administration (NOAA) and low frequency flask observations are together used to constrain the source and sink magnitudes, estimated as factors that multiply the a priori fluxes. Although industry data imply that the global industrial emissions were substantially declining with large interannual variations, the optimized results show only small interannual variations and a small decreasing trend. The global surface CCl4 mole fractions were declining in this period because the CCl4 oceanic and stratospheric sinks exceeded the industrial emissions. Compared to the a priori values, the inversion results indicate substantial increases in industrial emissions originating from the South Asian/Indian and Southeast Asian regions, and significant decreases in emissions from the European and North American regions.

  2. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    OpenAIRE

    N. Pirrone; Cinnirella, S.; Feng, X.; Finkelman, R. B.; H. R. Friedli; Leaner, J.; Mason, R.; Mukherjee, A B; Stracher, G. B.; D. G. Streets; K. Telmer

    2010-01-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial poi...

  3. Study of the impact of atmospheric emissions ({sup 41}AR) during operation of a nuclear reactor research

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Simone F.; Barreto, Alberto A.; Jacomino, Vanusa Maria F.; Rodrigues, Paulo Cesar H. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The knowledge of the atmosphere dispersion of radionuclides, resulting from a nuclear reactor emissions during normal operation, is an important step in the process of nuclear licensing and environmental. This step requires a study to evaluate the radiological environmental impact. The results of this study are used by radiation protection agents to control the exposure of public to radiation during the operation of nuclear facilities. The elaboration of environmental impact assessment due to atmospheric emissions is based on a study of atmospheric dispersion. The aim of this study is estimate the concentrations of radionuclides in different compartments of the ecosystem and calculate the dose received by man as a result of radiation exposure in different scenarios of interest. This paper deals with the case study of the impact of atmospheric emissions of {sup 41}Ar during operation of a nuclear research reactor. This study was accomplished with the application of the dispersion model ARTM (Radionuclide Transport Atmospheric Model), along with the geoprocessing resources. Among the results are: the spatial distribution of population by age; topography of the region, local wind rose, atmospheric stability and the estimate of the concentration of radionuclide {sup 41}Ar and of dose. The results indicate that the dose, by external irradiation due to immersion in the cloud, was below the limits established by regulatory agencies. (author)

  4. 49 CFR 193.2627 - Atmospheric corrosion control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Atmospheric corrosion control. 193.2627 Section... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2627 Atmospheric corrosion... atmospheric corrosion by— (a) Material that has been designed and selected to resist the corrosive...

  5. Control mechanisms for Nordic ship emissions

    Energy Technology Data Exchange (ETDEWEB)

    Martinsen, K. [DNV, Oslo (Norway); Torvanger, A. [Cicero, Oslo (Norway)

    2013-04-15

    Shipping today operates under a complex set of international and domestic regulations. However, the environmental regulations have lagged behind those of other industries. This situation is now changing quite dramatically. The increased focus on environmental issues, combined with the growing realisation of the actual pollution burden imposed by shipping, has led to an upsurge in both international and national regulations. Some are ready and will enter into force in the near future, while others are still being developed. On behalf of the Nordic Council of Ministers DNV has carried out a study on possible control mechanisms for Nordic ship emission. The aim is to assess the baseline shipping emissions and reduction potential and the possible controlling mechanisms (both incentives and regulations) available for reducing the emissions to air from shipping within the Nordic region. (Author)

  6. Modelling marine emissions and atmospheric distributions of halocarbons and DMS: the influence of prescribed water concentration vs. prescribed emissions

    Directory of Open Access Journals (Sweden)

    S. T. Lennartz

    2015-06-01

    Full Text Available Marine produced short-lived trace gases such as dibromomethane (CH2Br2, bromoform (CHBr3, methyliodide (CH3I and dimethylsulfide (DMS significantly impact tropospheric and stratospheric chemistry. Describing their marine emissions in atmospheric chemistry models as accurately as possible is necessary to quantify their impact on ozone depletion and the Earth's radiative budget. So far, marine emissions of trace gases have mainly been prescribed from emission climatologies, thus lacking the interaction between the actual state of the atmosphere and the ocean. Here we present simulations with the chemistry climate model EMAC with online calculation of emissions based on surface water concentrations, in contrast to directly prescribed emissions. Considering the actual state of the model atmosphere results in a concentration gradient consistent with model real-time conditions at ocean surface and atmosphere, which determine the direction and magnitude of the computed flux. This method has a number of conceptual and practical benefits, as the modelled emission can respond consistently to changes in sea surface temperature, surface wind speed, sea ice cover and especially atmospheric mixing ratio. This online calculation could enhance, dampen or even invert the fluxes (i.e. deposition instead of emissions of VSLS. We show that differences between prescribing emissions and prescribing concentrations (−28 % for CH2Br2 to +11 % for CHBr3 result mainly from consideration of the actual, time-varying state of the atmosphere. The absolute magnitude of the differences depends mainly on the surface ocean saturation of each particular gas. Comparison to observations from aircraft, ships and ground stations reveals that computing the air–sea flux interactively leads in most of the cases to more accurate atmospheric mixing ratios in the model compared to the computation from prescribed emissions. Calculating emissions online also enables effective testing of

  7. Attribution of atmospheric sulfur dioxide over the English Channel to dimethyl sulfide and changing ship emissions

    Science.gov (United States)

    Yang, Mingxi; Bell, Thomas G.; Hopkins, Frances E.; Smyth, Timothy J.

    2016-04-01

    Atmospheric sulfur dioxide (SO2) was measured continuously from the Penlee Point Atmospheric Observatory (PPAO) near Plymouth, United Kingdom, between May 2014 and November 2015. This coastal site is exposed to marine air across a wide wind sector. The predominant southwesterly winds carry relatively clean background Atlantic air. In contrast, air from the southeast is heavily influenced by exhaust plumes from ships in the English Channel as well as near Plymouth Sound. A new International Maritime Organization (IMO) regulation came into force in January 2015 to reduce the maximum allowed sulfur content in ships' fuel 10-fold in sulfur emission control areas such as the English Channel. Our observations suggest a 3-fold reduction in ship-emitted SO2 from 2014 to 2015. Apparent fuel sulfur content calculated from coincidental SO2 and carbon dioxide (CO2) peaks from local ship plumes show a high level of compliance to the IMO regulation (> 95 %) in both years (˜ 70 % of ships in 2014 were already emitting at levels below the 2015 cap). Dimethyl sulfide (DMS) is an important source of atmospheric SO2 even in this semi-polluted region. The relative contribution of DMS oxidation to the SO2 burden over the English Channel increased from about one-third in 2014 to about one-half in 2015 due to the reduction in ship sulfur emissions. Our diel analysis suggests that SO2 is removed from the marine atmospheric boundary layer in about half a day, with dry deposition to the ocean accounting for a quarter of the total loss.

  8. Mercury mass flow in iron and steel production process and its implications for mercury emission control.

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Gao, Wei; Wu, Qingru; Hao, Jiming

    2016-05-01

    The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to 41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%-49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute 29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%-36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven, sintering machine and blast furnace were 0.039-0.047gHg/ton steel, and for the electric furnace it was 0.021gHg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%-73% of total mercury emissions to air.

  9. Mercury mass flow in iron and steel production process and its implications for mercury emission control.

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Gao, Wei; Wu, Qingru; Hao, Jiming

    2016-05-01

    The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to 41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%-49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute 29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%-36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven, sintering machine and blast furnace were 0.039-0.047gHg/ton steel, and for the electric furnace it was 0.021gHg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%-73% of total mercury emissions to air. PMID:27155436

  10. [Diesel emission control technologies: a review].

    Science.gov (United States)

    He, Hong; Weng, Duan; Zi, Xin-Yun

    2007-06-01

    The authors reviewed the researches on diesel emission control for both new engine technologies and aftertreatment technologies. Emphases were focused on the recent advancements of the diesel particulate filter (DPF) and the selective catalytic reduction (SCR) of NO(x). In addition, it was explored for the future development in this field.

  11. Physiological parameters controlling plant-atmosphere ammonia exchange

    Science.gov (United States)

    Schjoerring, Jan K.; Husted, Søren; Mattsson, Marie

    Recent advances in characterizing the influence of different physiological and environmental parameters on NH 3 exchange between plants and the atmosphere are presented. A central parameter in controlling the rate and direction of NH 3 fluxes is the NH 3 compensation point. It may vary from below 1 to over 20 nmol NH 3 mol -1 air. High compensation points seem to be a result of high tissue N status, rapid absorption of NH +4 from the root medium and/or low activity of glutamine synthetase, a key enzyme in NH +4 assimilation. These conditions cause the NH +4 concentration in leaf apoplast and leaf cells to increase. The NH 3 compensation point also depends on plant developmental stage with peaks in NH 3 emission related to leaf senescence and N remobilization. The leaf temperature has a profound influence on the NH 3 compensation point: an increase in temperature from 15 to 30°C may cause a plant to switch from being a strong sink for atmospheric NH 3 to being a significant NH 3 source. Stomatal conductance for NH 3 relative to that of water vapour increases with tissue N status and with leaf senescence. At a given leaf temperature, the NH 3 compensation point can be successfully predicted on basis of the pH and NH +4 concentration in the apoplast of the mesophyll cells.

  12. Fast pulsed operation of a small non-radioactive electron source with continuous emission current control.

    Science.gov (United States)

    Cochems, P; Kirk, A T; Bunert, E; Runge, M; Goncalves, P; Zimmermann, S

    2015-06-01

    Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron current due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.

  13. Simulations of N2O concentrations for France using ecosystem models, emission databases and an atmospheric transport model

    Science.gov (United States)

    Massad, R. S.; Prieur, V.; Thompson, R.; Schultz, M.; Pison, I.; Bousquet, P.; Schmidt, M.; Lopez, M.; Boukari, E.; Lehuger, S.; Chaumartin, F.; Gabrielle, B.

    2012-04-01

    Soils are responsible for a major, although highly uncertain, share of the global emissions of nitrous oxide (N2O). N2O fluxes are strongly correlated to soil properties, soil management and local climatic conditions. These controlling factors interact at different temporal and spatial scales making it challenging to asses emissions at a regional level both with measurement and modeling. We used two biogeochemical simulation models CERES-EGC and O-CN to estimate N2O fluxes from agricultural soils over France, and compared them into the regional atmospheric chemistry-transport model CHIMERE (0.25°x0.25° for France). Comparisons between modelled and observed mixing ratios give insights on the quality of the emission scenarios used as input to the model, assuming small transport errors. The maps were tested by comparing CHIMERE simulations with time series of N2O atmospheric mixing ratios measured continuously in two locations over France during the year 2007. In an inverse mode, N2O emissions scenarios are used combination with N2O observed mixing ratios and an atmospheric transport model, to produce optimized emission scenarios. The model used is a global model (LMDZ-INCA, 3.75°x2.5° resolution with a 1°x1° zoom over Europe). For France the O-CN model which only accounts for crops and managed grassland emissions simulates total emissions of 95 Gg N-N2O/yr which are larger than total fluxes inferred from inversions (75 Gg N-N2O/yr). Inverted fluxes are 30% larger when compared to the prior emissions. Concerning CERES-EGC which only accounts for crops, the total emissions for 2007 sum-up to 20.4 Gg N-N2O/yr and are smaller than the total inverted flux.

  14. Test emission of uranium hexafluoride in atmosphere. Results interpretation

    International Nuclear Information System (INIS)

    To permit the modelization of gaseous uranium hexafluoride behaviour in atmosphere, a validation test has been executed the 10 April 1987. The experimental conditions, the main results and a comparison with a diffusion model are given in this report

  15. Mercury emissions to the atmosphere from natural and anthropogenic sources in the Mediterranean region

    Science.gov (United States)

    Pirrone, N.; Costa, P.; Pacyna, J. M.; Ferrara, R.

    This report discusses past, current and projected mercury emissions to the atmosphere from major industrial sources, and presents a first assessment of the contribution to the regional mercury budget from selected natural sources. Emissions (1995 estimates) from fossil fuels combustion (29.8 t yr -1) , cement production (28.8 t yr -1) and incineration of solid wastes (27.6 t yr -1) , all together account for about 82% of the regional anthropogenic total (105.7 t yr -1) . Other industrial sources in the region are smelters (4.8 t yr -1) , iron-steel plants (4.8 t yr -1) and other minor sources (chlor-alkali plants, crematoria, chemicals production) that have been considered together in the miscellaneous category (9.6 t yr -1) . Regional emissions from anthropogenic sources increased at a rate of 3% yr-1 from 1983 to 1995 and are projected to increase at a rate of 1.9% yr-1 in the next 25 years, if no improvement in emission control policy occurs. On a country-by-country basis, France is the leading emitter country with 22.6 t yr -1 followed by Turkey (16.1 t yr -1) , Italy (11.4 t yr -1) , Spain (9.1 t yr -1) , the former Yugoslavia 7.9 ( t yr -1) , Morocco (6.9 t yr -1) , Bulgaria (6.8 t yr -1) , Egypt (6.1 t yr -1) , Syria (3.6 t yr -1) , Libya (2.9 t yr -1) , Tunisia (2.8 t yr -1) and Greece (2.7 t yr -1) , whereas the remaining countries account for less than 7% of the regional total. The annual emission from natural sources is 110 t yr -1, although this figure only includes the volatilisation of elemental mercury from surface waters and emissions from volcanoes, whereas the contribution due to the degassing of mercury from top soil and vegetation has not been included in this first assessment. Therefore, natural and anthropogenic sources in the Mediterranean region release annually about 215 t of mercury, which represents a significant contribution to the total mercury budget released in Europe and to the global atmosphere.

  16. An assessment procedure for chemical utilisation schemes intended to reduce CO2 emissions to atmosphere

    NARCIS (Netherlands)

    Audus, H.; Oonk, H.

    1997-01-01

    The concept of reducing emissions of CO2 to the atmosphere by producing chemicals has been suggested by many people as a potential greenhouse gas mitigation option. The goal of such schemes is either: (i) fixation of CO2 in a chemical compound for a significant time, or, (ii) reduction of emissions

  17. Atmospheric emission of polychlorinated naphthalenes from iron ore sintering processes.

    Science.gov (United States)

    Liu, Guorui; Zheng, Minghui; Du, Bing; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Li, Cheng; Hu, Jicheng

    2012-10-01

    Iron ore sintering processes constitute significant sources of dioxins, and studies have confirmed a close correlation between polychlorinated naphthalenes (PCNs) and dioxin formation. Thus, iron ore sintering processes are thought to be a potential source of PCNs, although intensive investigations on PCN emissions from sintering processes have not been carried out. Therefore, the aim of the present study was to qualify and quantify PCN emissions from nine sintering plants operating on different industrial scales. PCN concentrations ranged from 3 to 983 ng m(-3) (0.4-23.3 pg TEQ(PCN) m(-3)) and emission factors ranged from 14 to 1749 μg t(-1) (0.5-41.5 ng TEQ(PCN) t(-1)), with a geometric mean of 84 μg t(-1) (2.1 ng TEQ(PCN) t(-1)). The estimated annual emission of PCNs from sintering processes in China was 1390 mg TEQ(PCN). These figures will assist in the development of a PCN emissions inventory. Regarding emission characteristics, PCNs mainly comprised low-chlorinated homologs. The ratios of several characteristic PCN congeners were also measured and compared with those from other sources. Taken together, these results may provide useful information for identifying the sources of PCNs produced by iron ore sintering processes.

  18. Study on the Total Amount Control of Atmospheric Pollutant Based on GIS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective To provide effective environmental management for total amount control of atmospheric pollutants. Methods An atmospheric diffusion model of sulfur dioxide on the surface of the earth was established and tested in Shantou of Guangdong Province on the basis of an overall assessment of regional natural environment, social economic state of development, pollution sources and atmospheric environmental quality. Compared with actual monitoring results in a studied region, simulation values fell within the range of two times of error and were evenly distributed in the two sides of the monitored values. Predicted with the largest emission model method, the largest emission of sulfur dioxide would be 54 279.792 tons per year in 2010. Conclusion The mathematical model established and revised on the basis of GIS is more rational and suitable for the regional characteristics of total amount control of air pollutants.

  19. Advanced Emissions Control Development Program: Phase III

    Energy Technology Data Exchange (ETDEWEB)

    G.T. Amrhein; R.T. Bailey; W. Downs; M.J. Holmes; G.A. Kudlac; D.A. Madden

    1999-07-01

    The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. The project goal is to effectively control air toxic emissions through the use of conventional flue gas clean-up equipment such as electrostatic precipitators (ESPs), fabric filters (baghouses - BH), and wet flue gas desulfurization systems (WFGD). Development work concentrated on the capture of trace metals, fine particulate, hydrogen chloride and hydrogen fluoride, with an emphasis on the control of mercury. The AECDP project is jointly funded by the US Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (OCDO), and Babcock and Wilcox, a McDermott company (B and W). This report discusses results of all three phases of the AECDP project with an emphasis on Phase III activities. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on characterization of the emissions of mercury and other air toxics and the control of these emissions for typical operating conditions of conventional flue gas clean-up equipment. Some general comments that can be made about the control of air toxics while burning a high-sulfur bituminous coal are as follows: (1) particulate control devices such as ESP's and baghouses do a good job of removing non-volatile trace metals, (2) particulate control devices (ESPs and baghouses) effectively remove the particulate-phase mercury, but the particulate-phase mercury was only a small fraction of the total for the coals tested, (3) wet scrubbing can effectively remove hydrogen chloride and hydrogen fluoride, and (4) wet scrubbers show good potential for the removal of mercury when operated under certain conditions, however, for certain applications, system enhancements can be required to achieve

  20. Global atmospheric emission inventory of polycyclic aromatic hydrocarbons (PAHs) for 2004

    Science.gov (United States)

    Zhang, Yanxu; Tao, Shu

    The global atmospheric emissions of the 16 polycyclic aromatic hydrocarbons (PAHs) listed as the US EPA priority pollutants were estimated using reported emission activity and emission factor data for the reference year 2004. A database for emission factors was compiled, and their geometric means and frequency distributions applied for emission calculation and uncertainty analysis, respectively. The results for 37 countries were compared with other PAH emission inventories. It was estimated that the total global atmospheric emission of these 16 PAHs in 2004 was 520 giga grams per year (Gg y -1) with biofuel (56.7%), wildfire (17.0%) and consumer product usage (6.9%) as the major sources, and China (114 Gg y -1), India (90 Gg y -1) and United States (32 Gg y -1) were the top three countries with the highest PAH emissions. The PAH sources in the individual countries varied remarkably. For example, biofuel burning was the dominant PAH source in India, wildfire emissions were the dominant PAH source in Brazil, while consumer products were the major PAH emission source in the United States. In China, in addition to biomass combustion, coke ovens were a significant source of PAHs. Globally, benzo(a)pyrene accounted for 0.05% to 2.08% of the total PAH emission, with developing countries accounting for the higher percentages. The PAH emission density varied dramatically from 0.0013 kg km -2 y in the Falkland Islands to 360 kg km -2 y in Singapore with a global mean value of 3.98 kg km -2 y. The atmospheric emission of PAHs was positively correlated to the country's gross domestic product and negatively correlated with average income. Finally, a linear bivariate regression model was developed to explain the global PAH emission data.

  1. Atmosphere control during debinding of powder injection molded parts

    Science.gov (United States)

    Moore, J. A.; Jarding, B. P.; Lograsso, B. K.; Anderson, I. E.

    1995-06-01

    Atmosphere control during debinding of powder injection molded (PIM) parts is an important parameter to consider. Experimental results have shown that a stagnant atmosphere containing volatiles evolved during debinding can cause slumping of the green samples. Removal of volatiles from the sample zone aids debinding and can reduce cycle times and improve sample quality. Residual carbon and oxygen can be controlled during debinding by adjusting the atmosphere composition. This paper presents the results of PIM 70 vol% spherical copper powder and 30 vol% binder. Debinding atmospheres were altered to determine the effect of debinding on the green body and the sintered sample.

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

    Energy Technology Data Exchange (ETDEWEB)

    Benkovitz, C.M.

    1997-09-01

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

  3. Scaling laws for perturbations in the ocean–atmosphere system following large CO2 emissions

    Directory of Open Access Journals (Sweden)

    N. Towles

    2015-07-01

    Full Text Available Scaling relationships are found for perturbations to atmosphere and ocean variables from large transient CO2 emissions. Using the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir (LOSCAR model (Zeebe et al., 2009; Zeebe, 2012b, we calculate perturbations to atmosphere temperature, total carbon, ocean temperature, total ocean carbon, pH, alkalinity, marine-sediment carbon, and carbon-13 isotope anomalies in the ocean and atmosphere resulting from idealized CO2 emission events. The peak perturbations in the atmosphere and ocean variables are then fit to power law functions of the form of γ DαEβ, where D is the event duration, E is its total carbon emission, and γ is a coefficient. Good power law fits are obtained for most system variables for E up to 50 000 PgC and D up to 100 kyr. Although all of the peak perturbations increase with emission rate E/D, we find no evidence of emission-rate-only scaling, α + β = 0. Instead, our scaling yields α + β ≃ 1 for total ocean and atmosphere carbon and 0 < α + β < 1 for most of the other system variables.

  4. The extrasolar planet atmosphere and exosphere: Emission and transmission spectroscopy

    CERN Document Server

    Tinetti, Giovanna

    2008-01-01

    We have entered the phase of extrasolar planets characterization, probing their atmospheres for molecules, constraining their horizontal and vertical temperature profiles and estimating the contribution of clouds and hazes. We report here a short review of the current situation using ground based and space based observations, and present the transmission spectra of HD189733b in the spectral range 0.5-24 microns.

  5. Emissions to the Atmosphere from Amine-Based Post Combustion CO2 Capture Plant – Regulatory Aspects

    Directory of Open Access Journals (Sweden)

    Azzi Merched

    2014-09-01

    Full Text Available Amine-based Post Combustion Capture (PCC of CO2 is a readily available technology that can be deployed to reduce CO2 emissions from coal fired power plants. However, PCC plants will likely release small quantities of amine and amine degradation products to the atmosphere along with the treated flue gas. The possible environmental effects of these emissions have been examined through different studies carried out around the world. Based on flue gas from a 400 MW ultra-supercritical coal fired power plant Aspen-Plus PCC process simulations were used to predict the potential atmospheric emissions from the plant. Different research initiatives carried out in this area have produced new knowledge that has significantly reduced the risk perception for the release of amine and amine degradation products to the atmosphere. In addition to the reduction of the CO2 emissions, the PCC technology will also help in reducing SOx and NO2 emissions. However, some other pollutants such as NH3 and aerosols will increase if appropriate control technologies are not adopted. To study the atmospheric photo-oxidation of amines, attempts are being made to develop chemical reaction schemes that can be used for air quality assessment. However, more research is still required in this area to estimate the reactivity of amino solvents in the presence of other pollutants such as NOx and other volatile organic compounds in the background air. Current air quality guidelines may need to be updated to include limits for the additional pollutants such as NH3, nitrosamines and nitramines once more information related to their emissions is available. This paper focuses on describing the predicted concentrations of major pollutants that are expected to be released from a coal fired power plant obtained by ASPEN-Plus PCC process simulations in terms of current air quality regulations and other regulatory aspects.

  6. Estimating European historical production, consumption and atmospheric emissions of decabromodiphenyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Earnshaw, Mark R., E-mail: m.earnshaw2@lancaster.ac.uk; Jones, Kevin C., E-mail: k.c.jones@lancaster.ac.uk; Sweetman, Andy J., E-mail: a.sweetman@lancaster.ac.uk

    2013-03-01

    A European scale production, consumption and environmental emissions inventory is produced for decabromodiphenyl ether (DecaBDE) for the period 1970–2020. A dynamic substance flow analysis model of DecaBDE is developed and emission of the main congener, BDE-209, to environmental compartments is estimated. From 1970 to 2010, it is estimated that a total of 185,000–250,000 tonnes of DecaBDE was consumed in Europe. Consumption peaked in the late 1990s at approximately 9000 tonnes/year and has declined by ∼ 30% in 2010. Predicted BDE-209 atmospheric emissions peak in 2004 at 10 tonnes/year. The waste management phase of the BDE-209 life cycle is responsible for the majority of atmospheric emissions via volatilisation and particle bound emissions from landfills, whilst leakage from Sewerage systems is the major source of emissions to the hydrosphere. Use of sewage sludge from wastewater treatment works as an agricultural fertiliser is the most important pathway of BDE-209 to soil. Although DecaBDE consumption has declined in recent years, the stock in use for 2010 remains considerable (60,000 tonnes) and is likely to act as a source of atmospheric emissions for several decades. Uncertainties exist in these estimations and more field or experimental data is needed to clarify the significance of certain emission pathways, in particular, emissions from landfill sites. - Highlights: ► Total DecaBDE consumption in Europe for the period 1970–2010 is estimated to be between 185,000 and 250,000 tonnes. ► European atmospheric emissions of BDE-209 is predicted to peak in 2004 at 10 tonnes/year. ► The waste management phase is responsible for the majority of BDE-209 environmental emissions. ► The volume of BDE-209 present in the anthroposphere is declining and is predicted to fall to negligible levels by 2030.

  7. Analysis and control of nitriding and nitrocarburizing atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Sproge, L. [AGA AB Lidingo (Sweden); Midea, S.J. [AGA Gas, Inc., Cleveland, OH (United States)

    1995-12-31

    This paper is a summary of research on control parameters and the factors which influence formation of compound layers in the nitriding and ferritic nitrocarburizing processes. The major gas-exchange reactions, mass-transfer mechanisms, and their kinetics are discussed for both these processes. Carbon, nitrogen and oxygen activities are calculated as a function of atmosphere gas composition. These activities are compared to experimental values and the obtained microstructures are analyzed. Development of a control scheme for these processes has been hindered both by a fundamental understanding of the atmosphere kinetics and a reliable means of monitoring the atmosphere. However, today there are possibilities to control such an atmosphere by means of an oxygen probe, utilizing software to calculate the atmosphere activities based upon the incoming gas mixture, temperature, and probe millivolt signal.

  8. Emission control of gas effluents from geothermal power plants.

    Science.gov (United States)

    Axtmann, R C

    1975-01-01

    Geothermal steam at the world's five largest power plants contains from 0.15 to 30% noncondensable gases including CO(2), H(2)S, H(2), CH(4), N(2), H(3)BO(3), and NH(3). At four of the plants the gases are first separated from the steam and then discharged to the environment; at the fifth, the noncondensables exhaust directly to the atmosphere along with spent steam. Some CO(2) and sulfur emission rates rival those from fossil-fueled plants on a per megawatt-day basis. The ammonia and boron effluents can interfere with animal and plant life. The effects of sulfur (which emerges as H(2)S but may oxidize to SO(2)) on either ambient air quality or longterm human health are largely unknown. Most geothermal turbines are equipped with direct contact condensers which complicate emission control because they provide two or more pathways for the effluents to reach the environment. Use of direct contact condensers could permit efficient emission control if coupled to processes that produce saleable quantities of purified carbon dioxide and elemental sulfur.

  9. [Effects of temperature and heating time on armco iron spectral emissivity in atmospheric environment].

    Science.gov (United States)

    Yu, Kun; Wang, Wen-Bao; Zhang, Kai-Hua; Liu, Yu-Fang

    2014-09-01

    The spectral emissivity of pure iron at 1.55 μm was investigated systematically by using our self-designed reflective experimental apparatus based on the Kirchhoff's law, and the influences of temperature and heating time on the spectral emissivity of pure iron were also discussed. The experimental data showed that the spectral emissivity of pure iron increased with temperature rising and its peak value and valley value appeared at certain temperatures. By analyzing the emissivity model of metal with oxidation layer, the variation of the spectral emissivity of pure iron was illustrated. The influence of heating time on the spectral emissivity was different at different temperature. The research results will further enrich pure iron spectral emissivity data, and provide the experimental basis for its application in atmospheric environment.

  10. A user experience-based approach to home atmosphere control

    NARCIS (Netherlands)

    Vastenburg, M.H.; Ross, P.R.; Keyson, D.V.

    2007-01-01

    The complex control problem of creating home atmospheres using light, music, and projected wall-art can be reduced by focusing on desired expe- rience, rather than product functions and features. A case study is described in which subjective interpreta- tions of living room atmospheres were measured

  11. State of the art incubator for controlled atmosphere studies

    DEFF Research Database (Denmark)

    Nielsen, Per Væggemose

    1998-01-01

    A state of the art incubator for studies of the biological effect of controlled atmosphere was designed. Working conditions are all combinations of: Temperature (5 to 40°C), Humidity (25 to 98%), oxygen (0.1 to 30%) and nitrogen (0.1 to 50%). Several points were given specific considerations...... without interfering with the atmosphere inside the chamber....

  12. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Science.gov (United States)

    Bouvier-Brown, N. C.; Goldstein, A. H.; Worton, D. R.; Matross, D. M.; Gilman, J. B.; Kuster, W. C.; Welsh-Bon, D.; Warneke, C.; de Gouw, J. A.; Cahill, T. M.; Holzinger, R.

    2009-03-01

    We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments - a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) - and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4-68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72-10.2 μgCg-1 h-1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  13. What would dense atmospheric observation networks bring to the quantification of city CO2 emissions?

    Science.gov (United States)

    Wu, Lin; Broquet, Grégoire; Ciais, Philippe; Bellassen, Valentin; Vogel, Felix; Chevallier, Frédéric; Xueref-Remy, Irène; Wang, Yilong

    2016-06-01

    Cities currently covering only a very small portion ( road transport, by 18 % for the production of energy by power plants, and by 31 % for total emissions. These results indicate that such a high number of stations would be likely required for the monitoring of sectoral emissions in Paris using this observation-model framework. They demonstrate some high potential that atmospheric inversions can contribute to the monitoring and/or the verification of city CO2 emissions (baseline) and CO2 emission reductions (commitments) and the advantage that could be brought by the current developments of lower-cost medium precision (LCMP) sensors.

  14. The Boston Methane Project: Mapping Surface Emissions to Inform Atmospheric Estimation of Urban Methane Flux

    Science.gov (United States)

    Phillips, N.; Crosson, E.; Down, A.; Hutyra, L.; Jackson, R. B.; McKain, K.; Rella, C.; Raciti, S. M.; Wofsy, S. C.

    2012-12-01

    Lost and unaccounted natural gas can amount to over 6% of Massachusetts' total annual greenhouse gas inventory (expressed as equivalent CO2 tonnage). An unknown portion of this loss is due to natural gas leaks in pipeline distribution systems. The objective of the Boston Methane Project is to estimate the overall leak rate from natural gas systems in metropolitan Boston, and to compare this flux with fluxes from the other primary methane emissions sources. Companion talks at this meeting describe the atmospheric measurement and modeling framework, and chemical and isotopic tracers that can partition total atmospheric methane flux into natural gas and non-natural gas components. This talk focuses on estimation of surface emissions that inform the atmospheric modeling and partitioning. These surface emissions include over 3,300 pipeline natural gas leaks in Boston. For the state of Massachusetts as a whole, the amount of natural gas reported as lost and unaccounted for by utility companies was greater than estimated landfill emissions by an order of magnitude. Moreover, these landfill emissions were overwhelmingly located outside of metro Boston, while gas leaks are concentrated in exactly the opposite pattern, increasing from suburban Boston toward the urban core. Work is in progress to estimate spatial distribution of methane emissions from wetlands and sewer systems. We conclude with a description of how these spatial data sets will be combined and represented for application in atmospheric modeling.

  15. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    Science.gov (United States)

    Graven, Heather D

    2015-08-01

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  16. N2O and NO2 Emissions from Heavy-Duty Diesel Trucks with Advanced Emission Controls

    Science.gov (United States)

    Preble, C.; Harley, R.; Kirchstetter, T.

    2014-12-01

    Diesel engines are the largest source of nitrogen oxides (NOx) emissions nationally, and also a major contributor to the black carbon (BC) fraction of fine particulate matter (PM). Recently, diesel particle filter (DPF) and selective catalytic reduction (SCR) emission control systems that target exhaust PM and NOx have become standard equipment on new heavy-duty diesel trucks. However, the deliberate catalytic oxidation of engine-out nitric oxide (NO) to nitrogen dioxide (NO2) in continuously regenerating DPFs leads to increased tailpipe emission of NO2. This is of potential concern due to the toxicity of NO2 and the resulting increases in atmospheric formation of other air pollutants such as ozone, nitric acid, and fine PM. While use of SCR reduces emissions of both NO and NO2, it may lead to increased emissions of nitrous oxide (N2O), a potent greenhouse gas. Here we report results from on-road measurements of heavy-duty diesel truck emissions conducted at the Port of Oakland and the Caldecott Tunnel in the San Francisco Bay Area. Emission factors (g pollutant per kg of diesel) were linked via recorded license plates to individual truck attributes, including engine model year and installed emission control equipment. Between 2009 and 2013, the fraction of DPF-equipped trucks at the Port of Oakland increased from 2 to 99%, and median engine age decreased from 11 to 6 years. Over the same period, fleet-average emission factors for black carbon and NOx decreased by 76 ± 22% and 53 ± 8%, respectively. However, direct emissions of NO2 increased, and consequently the NO2/NOx emission ratio increased from 0.03 ± 0.02 to 0.18 ± 0.03. Older trucks retrofitted with DPFs emitted approximately 3.5 times more NO2 than newer trucks equipped with both DPF and SCR. Preliminary data from summer 2014 measurements at the Caldecott Tunnel suggest that some older trucks have negative emission factors for N2O, and that for newer trucks, N2O emission factors have changed sign and

  17. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.

    Science.gov (United States)

    Niinemets, Ülo; Sun, Zhihong

    2015-02-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol(-1) or elevated [CO2] of 780 μmol mol(-1). The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size.

  18. 40 CFR 52.987 - Control of hydrocarbon emissions.

    Science.gov (United States)

    2010-07-01

    ... tons per year. (d) Installation of emission control systems on three 3,000 barrel capacity distillate...) Installation of emission control systems on crude oil storage tanks TK-43, TK-44, T-45 and T-49, and distillate... tons per year. (f) Installation of emission control systems on crude oil storage tanks TK-19-74,...

  19. Methane emission from flooded soils - from microorganisms to the atmosphere

    Science.gov (United States)

    Conrad, Ralf

    2016-04-01

    Methane is an important greenhouse gas that is affected by anthropogenic activity. The annual budget of atmospheric methane, which is about 600 million tons, is by more than 75% produced by methanogenic archaea. These archaea are the end-members of a microbial community that degrades organic matter under anaerobic conditions. Flooded rice fields constitute a major source (about 10%) of atmospheric methane. After flooding of soil, anaerobic processes are initiated, finally resulting in the disproportionation of organic matter to carbon dioxide and methane. This process occurs in the bulk soil, on decaying organic debris and in the rhizosphere. The produced methane is mostly ventilated through the plant vascular system into the atmosphere. This system also allows the diffusion of oxygen into the rizosphere, where part of the produced methane is oxidized by aerobic methanotrophic bacteria. More than 50% of the methane production is derived from plant photosynthetic products and is formed on the root surface. Methanocellales are an important group of methanogenic archaea colonizing rice roots. Soils lacking this group seem to result in reduced root colonization and methane production. In rice soil methane is produced by two major paths of methanogenesis, the hydrogenotrophic one reducing carbon dioxide to methane, and the aceticlastic one disproportionating acetate to methane and carbon dioxide. Theoretically, at least two third of the methane should be produced by aceticlastic and the rest by hydrogenotrophic methanogenesis. In nature, however, the exact contribution of the two paths can vary from zero to 100%. Several environmental factors, such as temperature and quality of organic matter affect the path of methane production. The impact of these factors on the composition and activity of the environmental methanogenic microbial community will be discussed.

  20. Atmospheric Pollutions Emissions, environmental challenges of Isfahan City

    OpenAIRE

    V. Ezzatian; S. Hasheminasab

    2013-01-01

    Extended abstract1-IntroductionThe recent fatal events with regard to the rise in the atmospheric pollutants levels have suggested that the reason of their occurrence be more identified. The long-term and short-term effects on the environment caused by pollutants that reached unacceptable level are apparent; existence of pollutatnts has led to short-term effects such as appearance and aggravation of cancer and respiratory‚ optic and lung diseases. The sequence of long-term effects is seen on ...

  1. Atmospheric three-dimensional inverse modeling of regional industrial emissions and global oceanic uptake of carbon tetrachloride

    Directory of Open Access Journals (Sweden)

    X. Xiao

    2010-11-01

    Full Text Available Carbon tetrachloride (CCl4 has substantial stratospheric ozone depletion potential and its consumption is controlled under the Montreal Protocol and its amendments. We implement a Kalman filter using atmospheric CCl4 measurements and a 3-dimensional chemical transport model to estimate the interannual regional industrial emissions and seasonal global oceanic uptake of CCl4 for the period of 1996–2004. The Model of Atmospheric Transport and Chemistry (MATCH, driven by offline National Center for Environmental Prediction (NCEP reanalysis meteorological fields, is used to simulate CCl4 mole fractions and calculate their sensitivities to regional sources and sinks using a finite difference approach. High frequency observations from the Advanced Global Atmospheric Gases Experiment (AGAGE and the Earth System Research Laboratory (ESRL of the National Oceanic and Atmospheric Administration (NOAA and low frequency flask observations are together used to constrain the source and sink magnitudes, estimated as factors that multiply the a priori fluxes. Although industry data imply that the global industrial emissions were substantially declining with large interannual variations, the optimized results show only small interannual variations and a small decreasing trend. The global surface CCl4 mole fractions were declining in this period because the CCl4 oceanic and stratospheric sinks exceeded the industrial emissions. Compared to the a priori values, the inversion results indicate substantial increases in industrial emissions originating from the South Asian/Indian and Southeast Asian regions, and significant decreases in emissions from the European and North American regions.

  2. Atmospheric Modeling and Verification of Point Source Fossil Fuel CO2 Emissions

    Science.gov (United States)

    Keller, E. D.; Turnbull, J. C.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.; Norris, M. W.; Zondervan, A.

    2014-12-01

    Emissions from large point sources (electricity generation and large-scale industry) of fossil fuel CO2 (CO2ff) emissions are currently determined from self-reported "bottom-up" inventory data, with an uncertainty of about 20% for individual power plants. As the world moves towards a regulatory environment, there is a need for independent, objective measurements of these emissions both to improve the accuracy of and to verify the reported amounts. "Top-down" atmospheric methods have the potential to independently constrain point source emissions, combining observations with atmospheric transport modeling to derive emission estimates. We use the Kapuni Gas Treatment Plant to examine methodologies and model sensitivities for atmospheric monitoring of point source fossil fuel CO2 (CO2ff) emissions. The Kapuni plant, located in rural New Zealand, removes and vents CO2 from locally extracted natural gas at a rate of ~0.1 Tg carbon per year. We measured the CO2ff content in three different types of observations: air samples collected in flasks over a period of a few minutes, sodium hydroxide solution exposed the atmosphere, and grass samples from the surrounding farmland, the latter two representing ~1 week integrated averages. We use the WindTrax Lagrangian plume dispersion model to compare these atmospheric observations with "expected" values given the emissions reported by the Kapuni plant. The model has difficulty accurately capturing the short-term variability in the flask samples but does well in representing the longer-term averages from grass samples, suggesting that passive integrated-sampling methods have the potential to monitor long-term emissions. Our results indicate that using this method, point source emissions can be verified to within about 30%. Further improvements in atmospheric transport modelling are needed to reduce uncertainties. In view of this, we discuss model strengths and weaknesses and explore model sensitivity to meteorological conditions

  3. Model-based guidance and control for atmospheric guided entry

    OpenAIRE

    Canuto, Enrico; Ospina, Jose Alejandro

    2012-01-01

    This paper presents a solution of the translational control for a biconic atmospheric entry capsule using the bank angle as a command. The control algorithm is separated into path planning and reference-path tracking. The path-planning algorithm computes the entry trajectory from the navigated state at the Entry Interface Point until the desired Parachute Deployment Point. The algorithm aims to recover the landing site uncertainty caused by Entry Interface Point dispersions. Atmospheric and a...

  4. Regional emission and loss budgets of atmospheric methane (2002-2012)

    Science.gov (United States)

    Saeki, T.; Patra, P. K.; Dlugokencky, E. J.; Ishijima, K.; Umezawa, T.; Ito, A.; Aoki, S.; Morimoto, S.; Kort, E. A.; Crotwell, A. M.; Ravi Kumar, K.; Nakazawa, T.

    2015-12-01

    Methane (CH4) plays important roles in atmospheric chemistry and short-term forcing of climate. Clear understanding of atmospheric CH4's budget of emissions and losses is required to aid sustainable development of Earth's future environment. We used an atmospheric chemistry-transport model (JAMSTEC's ACTM) for simulating atmospheric CH4. An inverse modeling system has been developed for estimating CH4 emissions (7 ensemble cases) from 53 land regions for 2002-2012 using measurements at 39 sites. Global net CH4 emissions varied between 505-509 and 524-545 Tg/yr during 2002-2004 and 2010-2012, respectively (ranges based on 6 inversion cases), with a step like increase in 2007 in agreement with atmospheric measurement. The inversion system did not account for interannual variations in radicals reacting with CH4 in atmosphere. Our results suggest that the recent update of EDGAR inventory (version 4.2FT2010) overestimated global total emissions by at least 25 Tg/yr in 2010. Increase in CH4 emission since 2004 originated in the tropical and southern hemisphere regions, with timing consistent with an increase of non-dairy cattle stocks by ~10% in 2012 from 1056 million heads in 2002, leading to ~10 Tg/yr increase in emissions from enteric fermentation. All 7 inversions robustly estimated the interannual variations in emissions, but poorly constrained the seasonal cycle amplitude or phase consistently for all regions due to sparse observational network. Forward simulation results using both the a priori and a posteriori emissions are compared with independent aircraft measurements for validation. By doing that we are able to reject the upper limit (545 Tg/yr) of global total emissions as 14 Tg/yr too high during 2008-2012, which allows us to further conclude that CH4 emission increase rate over the East Asia (China mainly) region was 7-8 Tg/yr between the 2002-2006 and 2008-2012 periods, contrary to 1-17 Tg/yr in the a priori emissions.

  5. Atmospheric CO2 capture by algae: Negative carbon dioxide emission path.

    Science.gov (United States)

    Moreira, Diana; Pires, José C M

    2016-09-01

    Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures. PMID:27005790

  6. Atmospheric CO2 capture by algae: Negative carbon dioxide emission path.

    Science.gov (United States)

    Moreira, Diana; Pires, José C M

    2016-09-01

    Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures.

  7. Isoprene leaf emission under CO2 free atmosphere: why and how?

    Science.gov (United States)

    Garcia, S.

    2015-12-01

    Isoprene (C5H8) is a reactive hydrocarbon gas emitted at high rates by tropical vegetation, which affects atmospheric chemistry and climate and, in the leaf level, is a very important agent against environmental stress. Under optimal conditions for photosynthesis, the majority of carbon used for isoprene biosynthesis is a direct product from recently assimilated atmospheric CO2. However, the contribution of 'alternate' carbon sources, that increase with leaf temperature, have been demonstrated and emissions of isoprene from 'alternate' carbon sources under ambient CO2 below the compensation point for photosynthesis have been observed. In this study, we investigated the response of leaf isoprene emissions under 450 ppm CO2 and CO2 free atmosphere as a function of light and leaf temperature. At constant leaf temperature (30 °C) and CO2 free atmospheres, leaves of the tropical species Inga edulis showed net emissions of CO2 and light-dependent isoprene emissions which stagnated at low light levels (75 µmol m-2 s-1 PAR) and account for 25% of that observed with 450 ppm CO2. Under constant light (1000 µmol m-2 s-1 PAR) and CO2 free atmospheres, a increase of leaf temperatures from 25 to 40 °C resulted in net emissions of CO2 and temperature-dependent isoprene emissions which reached values up to 17% of those under 450 ppm CO2. Our observations suggest that, under environmental stress, as high light/temperature and drought (when the stomata close and the amount of internal CO2 decreases), the 'alternate' carbon can maintain photosynthesis rates resulting in the production of isoprene, independent of atmospheric CO2, through the re-assimilation of internal released CO2 as an 'alternate' carbon sources for isoprene.

  8. Emission of trans, trans-2,4-decadienal from restaurant exhausts to the atmosphere

    Science.gov (United States)

    Yang, Hsi-Hsien; Chien, Shu-Mei; Lee, Hui-Ling; Chao, Mu-Rong; Luo, Hong-Wei; Hsieh, Dennis P. H.; Lee, Wen-Jhy

    Cooking exhausts may contribute significant organic compounds to the atmosphere. It has been shown that trans, trans-2,4-decadienal ( tt-DDE) is an important toxic compound in cooking oil fumes (COF). In this study, the emissions of tt-DDE were quantified in both gaseous and particulate phases of three kinds of restaurant exhausts (Chinese, western and barbecue). Samples of exhausts were collected with a sampling system meeting the criteria of US EPA Modified Method 5. The tt-DDE was analyzed by HPLC-MS/MS. The results indicate that the emission factors of tt-DDE in terms of μg customer -1 were in sequence: barbecue (1990)>Chinese (570)>western (63.8). The average proportion of tt-DDE in the particulate phase of the exhausts was 83% for the 16 investigated restaurants. Evidently, the majority of tt-DDE in the exhausts was in the particulate phase. There was no evident correlation found between phase distribution of tt-DDE and exhaust temperature in the restaurants investigated. The efficiencies of removal of particulate tt-DDE by air pollution control devices (APCDs) were assessed. The removal efficiencies of electrostatic precipitator (ESP), ESP and activated carbon in series, and wet scrubber were 64.2%, 86.3% and 71.3%, respectively.

  9. Atmospheric Pollutions Emissions, environmental challenges of Isfahan City

    Directory of Open Access Journals (Sweden)

    V. Ezzatian

    2013-01-01

    Full Text Available Extended abstract1-IntroductionThe recent fatal events with regard to the rise in the atmospheric pollutants levels have suggested that the reason of their occurrence be more identified. The long-term and short-term effects on the environment caused by pollutants that reached unacceptable level are apparent; existence of pollutatnts has led to short-term effects such as appearance and aggravation of cancer and respiratory‚ optic and lung diseases. The sequence of long-term effects is seen on DNA‚ intelligence and physiology. The air pollution results in water and soil pollution. Of course, aquatics and plants are under the influence of these pollutions. Men are not safe from them because they enter man’s food chain too. The statistical model represented in this research can estimate the acceptable rate of surface- ozone by measuring the climatic data of synoptic meteorology of Isfahan Station and evaluating surface pollution rate of station of the Environment Protection Agency. This research shows that equations that profited from two variables including square sunshine and square carbon monoxide concentration could explain %35 of concentration changes in surface- ozone during a day. Even though multivariable regression models can explain dramatical concentration changes in surface– ozone and protector concentration, practical use of these models is limited because of numerous entrance variables. Ozone as one of the most significant secondary pollutants not only influences general health but also has a considerable effect on agriculture. Surface – ozone is in ppm or ppb and it comprises the number of ozone molecules per million and per billion of air molecule.2- Theoretical basis As regards exceptional importance and poisonous state of ozone special in agriculture, it is essential to measure the rate of this gas for quantitative and qualitative survey of garden products and birds and livestock’s health. In general pollutants threat

  10. Simulations of atmospheric methane for Cape Grim, Tasmania, to constrain southeastern Australian methane emissions

    OpenAIRE

    Z. M. Loh; R. M. Law; Haynes, K. D.; P. B. Krummel; Steele, L. P.; P. J. Fraser; S. D. Chambers; Williams, A G

    2015-01-01

    This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E). The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS) and the CSIRO Conformal-Cubic Atmospheric Model (CCAM). Radon is also simulated and used to reduce the i...

  11. Simulations of atmospheric methane for Cape Grim, Tasmania, to constrain South East Australian methane emissions

    OpenAIRE

    Z. M. Loh; R. M. Law; Haynes, K. D.; P. B. Krummel; Steele, L. P.; P. J. Fraser; Chambers, S; Williams, A

    2014-01-01

    This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E). The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS) and the CSIRO Conformal-Cubic Atmospheric Model (CCAM). Radon is also simulated and used to reduce the i...

  12. Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers

    CERN Document Server

    Schellart, P; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P

    2015-01-01

    We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields.

  13. Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers.

    Science.gov (United States)

    Schellart, P; Trinh, T N G; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; Ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P

    2015-04-24

    We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields. PMID:25955053

  14. Soil greenhouse gases emissions reduce the benefit of mangrove plant to mitigating atmospheric warming effect

    OpenAIRE

    Chen, Guangcheng; Chen, Bin; Yu, Dan; Ye, Yong; Tam, Nora F. Y.; Chen, Shunyang

    2016-01-01

    Mangrove soils have been recognized as sources of atmospheric greenhouse gases but the atmospheric fluxes are poorly characterized, and their adverse warming effect has scarcely been considered with respect to the role of mangrove wetlands in mitigating global warming. The present study balanced the warming effect of soil greenhouse gas emissions with plant carbon dioxide (CO2) sequestration rate in a highly productive mangrove wetland in South China to assess the role of mangrove wetland in ...

  15. Effective pollutant emission heights for atmospheric transport modelling based on real-world information

    International Nuclear Information System (INIS)

    Emission data needed as input for the operation of atmospheric models should not only be spatially and temporally resolved. Another important feature is the effective emission height which significantly influences modelled concentration values. Unfortunately this information, which is especially relevant for large point sources, is usually not available and simple assumptions are often used in atmospheric models. As a contribution to improve knowledge on emission heights this paper provides typical default values for the driving parameters stack height and flue gas temperature, velocity and flow rate for different industrial sources. The results were derived from an analysis of the probably most comprehensive database of real-world stack information existing in Europe based on German industrial data. A bottom-up calculation of effective emission heights applying equations used for Gaussian dispersion models shows significant differences depending on source and air pollutant and compared to approaches currently used for atmospheric transport modelling. - The comprehensive analysis of real-world stack data provides detailed default parameter values for improving vertical emission distribution in atmospheric modelling

  16. Parameterization of atmospheric long-wave emissivity in a mountainous site for all sky conditions

    Directory of Open Access Journals (Sweden)

    J. Herrero

    2012-03-01

    Full Text Available Long-wave radiation is an important component of the energy balance of the Earth's surface. The downward component, emitted by the clouds and aerosols in the atmosphere, is rarely measured, and is still not well understood. In mountainous areas, the models existing for its estimation through the emissivity of the atmosphere do not give good results, and worse still in the presence of clouds. In order to estimate this emissivity for any atmospheric state and in a mountainous site, we related it to the screen-level values of temperature, relative humidity and solar radiation. This permitted the obtaining of: (1 a new set of parametric equations and (2 the modification of the Brutsaert's equation for cloudy skies through the calibration of C factor to 0.34 and the parameterization of the cloud index N. Both fitted to the surface data measured at a weather station at a height of 2500 m a.s.l. in Sierra Nevada, Spain. This study analyzes separately three significant atmospheric states related to cloud cover, which were also deduced from the screen-level meteorological data. Clear and totally overcast skies are accurately represented by the new parametric expressions, while the intermediate situations corresponding to partly clouded skies, concentrate most of the dispersion in the measurements and, hence, the error in the simulation. Thus, the modeling of atmospheric emissivity is greatly improved thanks to the use of different equations for each atmospheric state.

  17. Space shuttle observation of an unusual transient atmospheric emission

    Science.gov (United States)

    Yair, Yoav; Price, Colin; Ziv, Baruch; Israelevich, Peter L.; Sentman, Davis D.; São-Sabbas, Fernanda T.; Devir, Adam D.; Sato, Mitsuteru; Rodger, Craig J.; Moalem, Meir; Greenberg, Eran; Yaron, Ofer

    2005-01-01

    We report an observation of an unusual transient luminous event (TLE) detected in the near IR, south of Madagascar above the Indian Ocean. The event was imaged from the space shuttle Columbia during the MEIDEX sprite campaign [Yair et al., 2004]. It was delayed 0.23 seconds from a preceding visual lightning flash which was horizontally displaced >1000 km from the event. The calculated brightness in the 860 (+/-50) nm filter was ~310 +/- 30 kR, and the morphology of the emitting volume did not resemble any known class of TLE (i.e., sprites, ELVES or halos). This TIGER event (Transient Ionospheric Glow Emission in Red) may constitute a new class of TLE, not necessarily induced by a near-by thunderstorm. We discuss possible generation mechanisms, including the conjugate sprite hypothesis caused by lightning at the magnetic mirror point, lightning-induced electron precipitation and an extraterrestrial source, meteoric or cometary.

  18. Proceedings of impact of aircraft emissions upon the atmosphere. V. 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The study of the effect of aircraft on atmosphere is a new challenge that the scientific community has to face. This conference`s topics are various aspects of this challenge. The seven sessions of Volume 1 are: Present status and perspectives; Emission and traffic; Physics and chemistry of the aircraft wake; Natural and anthropogenic emissions - specific instrumentation; Global scale - chemistry; Global scale - climate. The 51 papers of Vol. 1. were indexed and abstracted individually for the Energy Database. (R.P.)

  19. Updated emission inventories for speciated atmospheric mercury from anthropogenic sources in China.

    Science.gov (United States)

    Zhang, Lei; Wang, Shuxiao; Wang, Long; Wu, Ye; Duan, Lei; Wu, Qingru; Wang, Fengyang; Yang, Mei; Yang, Hai; Hao, Jiming; Liu, Xiang

    2015-03-01

    China is the largest contributor to global atmospheric mercury (Hg), and accurate emission inventories in China are needed to reduce large gaps existing in global Hg mass balance estimates and assess Hg effects on various ecosystems. The China Atmospheric Mercury Emission (CAME) model was developed in this study using probabilistic emission factors generated from abundant on-site measurements and literature data. Using this model, total anthropogenic Hg emissions were estimated to be continuously increasing from 356 t in 2000 to 538 t in 2010 with an average annual increase rate of 4.2%. Industrial coal combustion, coal-fired power plants, nonferrous metal smelting, and cement production were identified to be the dominant Hg emission sources in China. The ten largest contributing provinces accounted for nearly 60% of the total Hg emissions in 2010. Speciated Hg emission inventory was developed over China with a grid-resolution of 36 × 36 km, providing needed emission fields for Hg transport models. In this new inventory, the sectoral Hg speciation profiles were significantly improved based on the latest data from field measurements and more detailed technology categorization. The overall uncertainties of the newly developed inventory were estimated to be in the range of -20% to +23%. PMID:25655106

  20. 40 CFR 89.110 - Emission control information label.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Emission control information label. 89.110 Section 89.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Standards and Certification Provisions §...

  1. Soil organic carbon dust emission: an omitted global source of atmospheric CO2.

    Science.gov (United States)

    Chappell, Adrian; Webb, Nicholas P; Butler, Harry J; Strong, Craig L; McTainsh, Grant H; Leys, John F; Viscarra Rossel, Raphael A

    2013-10-01

    Soil erosion redistributes soil organic carbon (SOC) within terrestrial ecosystems, to the atmosphere and oceans. Dust export is an essential component of the carbon (C) and carbon dioxide (CO(2)) budget because wind erosion contributes to the C cycle by removing selectively SOC from vast areas and transporting C dust quickly offshore; augmenting the net loss of C from terrestrial systems. However, the contribution of wind erosion to rates of C release and sequestration is poorly understood. Here, we describe how SOC dust emission is omitted from national C accounting, is an underestimated source of CO(2) and may accelerate SOC decomposition. Similarly, long dust residence times in the unshielded atmospheric environment may considerably increase CO(2) emission. We developed a first approximation to SOC enrichment for a well-established dust emission model and quantified SOC dust emission for Australia (5.83 Tg CO(2)-e yr(-1)) and Australian agricultural soils (0.4 Tg CO(2)-e yr(-1)). These amount to underestimates for CO(2) emissions of ≈10% from combined C pools in Australia (year = 2000), ≈5% from Australian Rangelands and ≈3% of Australian Agricultural Soils by Kyoto Accounting. Northern hemisphere countries with greater dust emission than Australia are also likely to have much larger SOC dust emission. Therefore, omission of SOC dust emission likely represents a considerable underestimate from those nations' C accounts. We suggest that the omission of SOC dust emission from C cycling and C accounting is a significant global source of uncertainty. Tracing the fate of wind-eroded SOC in the dust cycle is therefore essential to quantify the release of CO(2) from SOC dust to the atmosphere and the contribution of SOC deposition to downwind C sinks.

  2. The efficiency and sensitivity analysis of observations for atmospheric transport model with emissions

    Science.gov (United States)

    Wu, Xueran; Elbern, Hendrik; Jacob, Birgit

    2015-04-01

    Air quality and climate change are influenced by the fluxes of green house gases, reactive emissions and aerosols in the atmosphere. But observations of the chemical states in the atmosphere typically have low temporal and spatial density. Therefore, many works are introduced to spatio-temporal data assimilation methods in atmospheric chemistry in recent years. There is no doubt that the optimization of the initial state is always of great importance for the improvement of predictive skill. However, specified to the chemistry transport model with high dependence on the emissions in the troposphere, the optimization of the initial state is no longer the only issue. The lack of the ability to observe and estimate surface emission fluxes and important inner atmospheric fluxes with necessary accuracy is a major roadblock of hampering the progress in predictive skills of the atmospheric transport model. However, in many cases, the better estimations for both the initial state and emission rates are not always obtained with certain observational network configurations via various popular data assimilation methods, such as the ensemble Kalman filter and smoother and 4D-variation. It leads to the waste of resource by optimizing the improper parameters or brings the inaccuracy of the optimization by unsuitable weight between the initial state and emission rates. Hence, in order to make a scientific and quantitative decision about which parameters to be optimized and how to balance them before any data assimilation procedure, we establish the dynamic model for emission rates with the constraint of diurnal profile shape and extend the state vector of atmospheric transport model so that the emission rates are included. Then, a theoretical approach, based on Kalman filter and smoother and their ensemble cases, to evaluate the potential improvement is introduced. By singular value decomposition, the efficiency of observations to optimize initial state and emission rates of the

  3. Regional Atmospheric Transport Code for Hanford Emission Tracking, Version 2(RATCHET2)

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, James V.; Rishel, Jeremy P.

    2006-07-01

    This manual describes the atmospheric model and computer code for the Atmospheric Transport Module within SAC. The Atmospheric Transport Module, called RATCHET2, calculates the time-integrated air concentration and surface deposition of airborne contaminants to the soil. The RATCHET2 code is an adaptation of the Regional Atmospheric Transport Code for Hanford Emissions Tracking (RATCHET). The original RATCHET code was developed to perform the atmospheric transport for the Hanford Environmental Dose Reconstruction Project. Fundamentally, the two sets of codes are identical; no capabilities have been deleted from the original version of RATCHET. Most modifications are generally limited to revision of the run-specification file to streamline the simulation process for SAC.

  4. A model to calculate consistent atmospheric emission projections and its application to Spain

    Science.gov (United States)

    Lumbreras, Julio; Borge, Rafael; de Andrés, Juan Manuel; Rodríguez, Encarnación

    Global warming and air quality are headline environmental issues of our time and policy must preempt negative international effects with forward-looking strategies. As part of the revision of the European National Emission Ceilings Directive, atmospheric emission projections for European Union countries are being calculated. These projections are useful to drive European air quality analyses and to support wide-scale decision-making. However, when evaluating specific policies and measures at sectoral level, a more detailed approach is needed. This paper presents an original methodology to evaluate emission projections. Emission projections are calculated for each emitting activity that has emissions under three scenarios: without measures (business as usual), with measures (baseline) and with additional measures (target). The methodology developed allows the estimation of highly disaggregated multi-pollutant, consistent emissions for a whole country or region. In order to assure consistency with past emissions included in atmospheric emission inventories and coherence among the individual activities, the consistent emission projection (CEP) model incorporates harmonization and integration criteria as well as quality assurance/quality check (QA/QC) procedures. This study includes a sensitivity analysis as a first approach to uncertainty evaluation. The aim of the model presented in this contribution is to support decision-making process through the assessment of future emission scenarios taking into account the effect of different detailed technical and non-technical measures and it may also constitute the basis for air quality modelling. The system is designed to produce the information and formats related to international reporting requirements and it allows performing a comparison of national results with lower resolution models such as RAINS/GAINS. The methodology has been successfully applied and tested to evaluate Spanish emission projections up to 2020 for 26

  5. Atomic carbon in comet atmospheres. Origin and emission spectra

    International Nuclear Information System (INIS)

    A detailed study of neutral carbon emissions is made, to precise the excitation mechanism nature, to determine the production mechanisms and examine wether information on CO and CO2 molecule abundance could be deduced, or wether another source must be looked for. After an exhaustive study of excitation rates necessary for theoretical intensity calculation, a new effect has been discovered, and which acts on the atom excitation rates, via their distribution on the fundamental hyperfine levels. On the other hand, the strong dependency of the excitation rate ratio with heliocentric velocity and with the hypothesis which is made on the atom population initial distribution has been revealed. The carbon abundance in all the comets of the initial sample has been calculated, then compared to the water one revealing two groups of comets. Then an abundance criterium to remove the CO and CO2 molecules from the carbon potential-parents in the Bradfield comet has been used while CO is the best candicate for C(3P) and C(1D) atom production in the West, Kohoutek and Bennet comets (but to certain conditions). The important conclusion is that, while the relative abundance (C2/OH, CN/OH,...) of the minor carbon compounds were constant, the CO relative abundance varies from an object to the other, probably an effect due to repeated passage of some comets near the sun

  6. Remarkably improved field emission of TiO2 nanotube arrays by annealing atmosphere engineering

    International Nuclear Information System (INIS)

    Highlights: • TNAs were prepared by anodization and annealed in different atmospheres. • The crystal structure and electronic properties of the prepared TNAs were investigated. • The field emission of TNAs was highly dependent on annealing atmosphere. • A low turn-on of 2.44 V/μm was obtained for TNAs annealed in H2 atmosphere. - Abstract: Highly ordered TiO2 nanotube arrays (TNAs) were prepared by anodization, and followed by annealing in the atmospheres of Air, Vacuum, Ar, and H2. The effect of annealing atmosphere on the crystal structure, composition, and electronic properties of TNAs were systematically investigated. Raman and EDS results indicated that the TNAs annealed in anaerobic atmospheres contained more oxygen vacancies, which result in the substantially improved electron transport properties and reduced work function. Moreover, it was found that the FE properties of TNAs were highly dependent on the annealing atmosphere. By engineering the annealing atmosphere, the turn-on field as low as 2.44 V/μm can be obtained from TNAs annealed in H2, which was much lower than the value of 18.23 V/μm from the TNAs annealed in the commonly used atmosphere of Air. Our work suggests an instructive and attractive way to fabricate high performance TNAs field emitters

  7. Remarkably improved field emission of TiO{sub 2} nanotube arrays by annealing atmosphere engineering

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Ai-Zhen; Wang, Cheng-Wei, E-mail: cwwang@nwnu.edu.cn; Chen, Jian-Biao; Zhang, Xu-Qiang; Li, Yan; Wang, Jian

    2015-10-15

    Highlights: • TNAs were prepared by anodization and annealed in different atmospheres. • The crystal structure and electronic properties of the prepared TNAs were investigated. • The field emission of TNAs was highly dependent on annealing atmosphere. • A low turn-on of 2.44 V/μm was obtained for TNAs annealed in H{sub 2} atmosphere. - Abstract: Highly ordered TiO{sub 2} nanotube arrays (TNAs) were prepared by anodization, and followed by annealing in the atmospheres of Air, Vacuum, Ar, and H{sub 2}. The effect of annealing atmosphere on the crystal structure, composition, and electronic properties of TNAs were systematically investigated. Raman and EDS results indicated that the TNAs annealed in anaerobic atmospheres contained more oxygen vacancies, which result in the substantially improved electron transport properties and reduced work function. Moreover, it was found that the FE properties of TNAs were highly dependent on the annealing atmosphere. By engineering the annealing atmosphere, the turn-on field as low as 2.44 V/μm can be obtained from TNAs annealed in H{sub 2}, which was much lower than the value of 18.23 V/μm from the TNAs annealed in the commonly used atmosphere of Air. Our work suggests an instructive and attractive way to fabricate high performance TNAs field emitters.

  8. Analytical Framework to Evaluate Emission Control Systems for Marine Engines

    OpenAIRE

    Jayaram, Varalakshmi

    2010-01-01

    Emissions from marine diesel engines are mainly uncontrolled and affect regional air quality and health of people living near ports. Many emission control strategies are evolving to reduce these emissions and their impacts. This dissertation characterizes the effectiveness of new technologies for reducing NOx and PM2.5 emissions from a range of marine diesel engines. Researchers, regulators and policy makers require these characterizations to develop emission inventories and suitable mitigati...

  9. LA Megacity: An Integrated Land-Atmosphere System for Urban CO2 Emissions

    Science.gov (United States)

    Feng, S.; Lauvaux, T.; Newman, S.; Rao, P.; Patarasuk, R.; o'Keefe, D.; Huang, J.; Ahmadov, R.; Wong, C.; Song, Y.; Gurney, K. R.; Diaz Isaac, L. I.; Jeong, S.; Fischer, M. L.; Miller, C. E.; Duren, R. M.; Li, Z.; Yung, Y. L.; Sander, S. P.

    2015-12-01

    About 10% of the global population lives in the word's 20 megacities (cities with urban populations greater than 10 million people). Megacities account for approximately 20% of the global anthropogenic fossil fuel CO2 (FFCO2) emissions, and their proportion of emissions increases monotonically with the world population and urbanization. Megacities range in spatial extent from ~1000 - 10,000 km2 with complex topography and variable landscapes. We present here the first attempt at building an integrated land-atmosphere modeling system for megacity environments, developed and evaluated for urban CO2 emissions over the Los Angeles (LA) Megacity area. The Weather Research and Forecasting (WRF) - Chem model was coupled to a ~1.3-km FFCO2 emission product, "Hestia-LA", to simulate the transport of CO2 across the LA magacity. We define the optimal model resolution to represent both the spatial variability of the atmospheric dynamics and the spatial patterns from the CO2 emission distribution. In parallel, we evaluate multiple configurations of WRF with various physical schemes, using meteorological observations from the CalNex-LA campaign of May-June 2010. Our results suggest that there is no remarkable difference between the medium- (4-km) and high- (1.3-km) resolution simulations in terms of atmospheric model performance. However, the high-resolution modeled CO2 mixing ratios clearly outperform the results at medium resolution for capturing both the spatial distribution and the temporal variability of the urban CO2 signals. We compare the impact of physical representation errors and emission aggregation errors on the modeled CO2 mixing ratios across the LA megacity. Finally, we present a novel approach to evaluate the design of the current surface network over the LA megacity using the modeled spatial correlations. These results reinforce the importance of using high-resolution emission products over megacities to represent correctly the large spatial gradients in

  10. CONTROL OF HYDROCARBON EMISSIONS FROM GASOLINE LOADING BY REFRIGERATION SYSTEMS

    Science.gov (United States)

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

  11. Improved controlled atmosphere high temperature scanning probe microscope

    OpenAIRE

    Hansen, Karin Vels; Wu, Yuehua; Jacobsen, Torben; Mogensen, Mogens Bjerg; Kuhn, Luise Theil

    2013-01-01

    To locally access electrochemical active surfaces and interfaces in operando at the sub-micron scale at high temperatures in a reactive gas atmosphere is of great importance to understand the basic mechanisms in new functional materials, for instance, for energy technologies, such as solid oxide fuel cells and electrolyzer cells. Here, we report on advanced improvements of our original controlled atmosphere high temperature scanning probe microscope, CAHT-SPM. The new microscope can employ a ...

  12. Inverse modelling of national and European CH4 emissions using the atmospheric zoom model TM5

    NARCIS (Netherlands)

    Bergamaschi, P.; Krol, M.C.; Dentener, F.; Vermeulen, A.; Meinhardt, F.; Graul, R.; Ramonet, M.; Peters, W.; Dlugokencky, E.J.

    2005-01-01

    A synthesis inversion based on the atmospheric zoom model TM5 is used to derive top-down estimates of CH4 emissions from individual European countries for the year 2001. We employ a model zoom over Europe with 1° × 1° resolution that is two-way nested into the global model domain (with resolution of

  13. Probing atmospheric electric fields in thunderstorms through radio emission from cosmic-ray induced air showers

    NARCIS (Netherlands)

    Trinh, Gia Thi Ngoc; Schellart, Pim; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Horandel, Jörg R.; Nelles, Anna; Rachen, Jörg Paul; Rutjes, Casper; Scholten, Olaf; ter Veen, Sander; Thoudam, Satyendra

    2015-01-01

    Energetic cosmic rays impinging on the atmosphere create a particle avalanche called extensive air shower. In the leading plasma of this shower electric currents are induced that generate the emission of radio waves which have been detected with LOFAR, an array of a large number of simple antennas p

  14. Parameterization of subgrid aircraft emission plumes for use in large-scale atmospheric simulations

    Directory of Open Access Journals (Sweden)

    M. Z. Jacobson

    2009-11-01

    Full Text Available Aircraft emissions differ from other anthropogenic pollution in that they occur mainly in the upper troposphere and lower stratosphere where they can form condensation trails (contrails and affect cirrus cloud cover. In determining the effect of aircraft on climate, it is therefore necessary to examine these processes. Previous studies have approached this problem by treating aircraft emissions on the grid scale, but this neglects the subgrid scale nature of aircraft emission plumes. We present a new model of aircraft emission plume dynamics that is intended to be used as a subgrid scale model in a large scale atmospheric simulation. The model shows good agreement with a large eddy simulation of aircraft emission plume dynamics and with an analytical solution to the dynamics of a sheared Gaussian plume. We argue that this provides a reasonable model of line-shaped contrail dynamics and give an example of how it might be applied in a global climate model.

  15. Parameterization of subgrid aircraft emission plumes for use in large-scale atmospheric simulations

    Science.gov (United States)

    Naiman, A. D.; Lele, S. K.; Wilkerson, J. T.; Jacobson, M. Z.

    2009-11-01

    Aircraft emissions differ from other anthropogenic pollution in that they occur mainly in the upper troposphere and lower stratosphere where they can form condensation trails (contrails) and affect cirrus cloud cover. In determining the effect of aircraft on climate, it is therefore necessary to examine these processes. Previous studies have approached this problem by treating aircraft emissions on the grid scale, but this neglects the subgrid scale nature of aircraft emission plumes. We present a new model of aircraft emission plume dynamics that is intended to be used as a subgrid scale model in a large scale atmospheric simulation. The model shows good agreement with a large eddy simulation of aircraft emission plume dynamics and with an analytical solution to the dynamics of a sheared Gaussian plume. We argue that this provides a reasonable model of line-shaped contrail dynamics and give an example of how it might be applied in a global climate model.

  16. Does chronic nitrogen deposition during biomass growth affect atmospheric emissions from biomass burning?

    International Nuclear Information System (INIS)

    Chronic nitrogen deposition has measureable impacts on soil and plant health. We investigate burning emissions from biomass grown in areas of high and low NOx deposition. Gas and aerosol-phase emissions were measured as a function of photochemical aging in an environmental chamber at UC-Riverside. Though aerosol chemical speciation was not available, results indicate a systemic compositional difference between biomass grown in high and low deposition areas. Aerosol emissions from biomass grown in areas of high NOx deposition exhibit a lower volatility than biomass grown in a low deposition area. Furthermore, fuel elemental analysis, NOx emission rates, and aerosol particle number distributions differed significantly between the two sites. Despite the limited scale of fuels explored, there is strong evidence that the atmospheric emissions community must pay attention to the regional air quality of biomass fuels growth areas. (letter)

  17. Implications of diesel emissions control failures to emission factors and road transport NOx evolution

    Science.gov (United States)

    Ntziachristos, Leonidas; Papadimitriou, Giannis; Ligterink, Norbert; Hausberger, Stefan

    2016-09-01

    Diesel NOx emissions have been at the forefront of research and regulation scrutiny as a result of failures of late vehicle technologies to deliver on-road emissions reductions. The current study aims at identifying the actual emissions levels of late light duty vehicle technologies, including Euro 5 and Euro 6 ones. Mean NOx emission factor levels used in the most popular EU vehicle emission models (COPERT, HBEFA and VERSIT+) are compared with latest emission information collected in the laboratory over real-world driving cycles and on the road using portable emissions measurement systems (PEMS). The comparison shows that Euro 5 passenger car (PC) emission factors well reflect on road levels and that recently revealed emissions control failures do not call for any significant corrections. However Euro 5 light commercial vehicles (LCVs) and Euro 6 PCs in the 2014-2016 period exhibit on road emission levels twice as high as used in current models. Moreover, measured levels vary a lot for Euro 6 vehicles. Scenarios for future evolution of Euro 6 emission factors, reflecting different degree of effectiveness of emissions control regulations, show that total NOx emissions from diesel Euro 6 PC and LCV may correspond from 49% up to 83% of total road transport emissions in 2050. Unless upcoming and long term regulations make sure that light duty diesel NOx emissions are effectively addressed, this will have significant implications in meeting future air quality and national emissions ceilings targets.

  18. Atmospheric three-dimensional inverse modeling of regional industrial emissions and global oceanic uptake of carbon tetrachloride

    Directory of Open Access Journals (Sweden)

    X. Xiao

    2010-05-01

    Full Text Available Carbon tetrachloride (CCl4 has substantial stratospheric ozone depletion potential and its consumption is controlled under the Montreal Protocol and its amendments. We implement a Kalman filter using atmospheric CC14 measurements and a 3-dimensional chemical transport model to estimate the interannual regional industrial emissions and seasonal global oceanic uptake of CCl4 for the period of 1996–2004. The Model of Atmospheric Transport and Chemistry (MATCH, driven by offline National Center for Environmental Prediction (NCEP reanalysis meteorological fields, is used to simulate CCl4 mole fractions and calculate their sensitivities to regional sources and sinks using a finite difference approach. High frequency observations from the Advanced Global Atmospheric Gases Experiment (AGAGE and NOAA Earth System Research Laboratory (ESRL and low frequency flask observations are together used to constrain the source and sink magnitudes, estimated as factors that multiply the a priori fluxes. Although industry data imply that the global industrial emissions were substantially declining with large interannual variations, the optimized results show only small interannual variations and a small decreasing trend. The global surface CCl4 mole fractions were declining in this period because the CCl4 oceanic and stratospheric sinks exceeded the industrial emissions. Compared to the a priori values, the inversion results indicate substantial increases in industrial emissions originating from the South Asian/Indian and Southeast Asian regions, and significant decreases in emissions from the European and North American regions.

  19. Atmospheric mercury emissions in Australia from anthropogenic, natural and recycled sources

    Science.gov (United States)

    Nelson, Peter F.; Morrison, Anthony L.; Malfroy, Hugh J.; Cope, Martin; Lee, Sunhee; Hibberd, Mark L.; Meyer, C. P. (Mick); McGregor, John

    2012-12-01

    The United Nations Environment Programme (UNEP) has begun a process of developing a legally binding instrument to manage emissions of mercury from anthropogenic sources. The UNEP Governing Council has concluded that there is sufficient evidence of significant global adverse impacts from mercury to warrant further international action; and that national, regional and global actions should be initiated as soon as possible to identify populations at risk and to reduce human generated releases. This paper describes the development of, and presents results from, a comprehensive, spatially and temporally resolved inventory of atmospheric mercury emissions from the Australian landmass. Results indicate that the best estimate of total anthropogenic emissions of mercury to the atmosphere in 2006 was 15 ± 5 tonnes. Three industrial sectors contribute substantially to Australian anthropogenic emissions: gold smelting (˜50%, essentially from a single site/operation), coal combustion in power plants (˜15%) and alumina production from bauxite (˜12%). A diverse range of other sectors contribute smaller proportions of the emitted mercury, but industrial emissions account for around 90% of total anthropogenic mercury emissions. The other sectors include other industrial sources (mining, smelting, and cement production) and the use of products containing mercury. It is difficult to determine historical trends in mercury emissions given the large uncertainties in the data. Estimates for natural and re-emitted emissions from soil, water, vegetation and fires are made using meteorological models, satellite observations of land cover and soil and vegetation type, fuel loading, fire scars and emission factors which account for the effects of temperature, insolation and other environmental variables. These natural and re-emitted sources comfortably exceed the anthropogenic emissions, and comprise 4-12 tonnes per year from vegetation, 70-210 tonnes per year from soils, and 21-63 tonnes

  20. Gridded atmospheric emission inventory of 2,3,7,8-TCDD in China

    Science.gov (United States)

    Huang, Tao; Tian, Chongguo; Zhang, Kai; Gao, Hong; Li, Yi-Fan; Ma, Jianmin

    2015-05-01

    Establishment of the dioxins emission inventory has been considered as a crucial step toward risk assessment and elimination of dioxins contaminations. Based on a total dioxin emission inventory in China from different emission categories in 2004, this study created a gridded emission inventory of 2,3,7,8-TCDD, the most toxic congener in dioxins, in China in 2009 with a 1/4° longitude by 1/4° latitude resolution. It was estimated that annually total 371 ± 53 g (average ± standard deviation) of 2,3,7,8-TCDD was released into the atmosphere in 2009 over China, increasing approximately by 37% compared with its emission in 2004. Differing from most developed countries where municipal waste incinerations were regarded as a major atmospheric emission source, in China ferrous and non-ferrous metal production made the largest contribution to 2,3,7,8-TCDD air emission (138 ± 16 g), followed by waste incineration (109 ± 12 g), power and heating generation (62 ± 9 g), and production of mineral products (47 ± 8 g). The rest of sources contributed approximately 3% to the total 2,3,7,8-TCDD emission in 2009. Iron and steel industries are mainly located in Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) regions, whereas waste incinerators are mainly located in Pearl River Delta (PRD) region. Higher 2,3,7,8-TCDD emissions were found in these three regions. While the BTH, YRD, and PRD accounted for only about 4% of total land area of China, they contributed approximately 14%, 15%, and 5% to the total 2,3,7,8-TCDD emission in 2009 in China, respectively.

  1. Controlling nanowire emission profile using conical taper

    DEFF Research Database (Denmark)

    Gregersen, Niels; Nielsen, Torben Roland; Mørk, Jesper;

    2008-01-01

    The influence of a conical taper on nanowire light emission is studied. For nanowires with divergent output beams, the introduction of tapers improves the emission profile and increase the collection efficiency of the detection optics....

  2. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    Science.gov (United States)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  3. Optical Emission Spectroscopy of an Atmospheric Pressure Plasma Jet During Tooth Bleaching Gel Treatment.

    Science.gov (United States)

    Šantak, Vedran; Zaplotnik, Rok; Tarle, Zrinka; Milošević, Slobodan

    2015-11-01

    Optical emission spectroscopy was performed during atmospheric pressure plasma needle helium jet treatment of various tooth-bleaching gels. When the gel sample was inserted under the plasma plume, the intensity of all the spectral features increased approximately two times near the plasma needle tip and up to two orders of magnitude near the sample surface. The color change of the hydroxylapatite pastille treated with bleaching gels in conjunction with the atmospheric pressure plasma jet was found to be in correlation with the intensity of OH emission band (309 nm). Using argon as an additive to helium flow (2 L/min), a linear increase (up to four times) of OH intensity and, consequently, whitening (up to 10%) of the pastilles was achieved. An atmospheric pressure plasma jet activates bleaching gel, accelerates OH production, and accelerates tooth bleaching (up to six times faster).

  4. Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California.

    Science.gov (United States)

    Zhang, Hongliang; Magara-Gomez, Kento T; Olson, Michael R; Okuda, Tomoaki; Walz, Kenneth A; Schauer, James J; Kleeman, Michael J

    2015-12-15

    The use of biodiesel as a replacement for petroleum-based diesel fuel has gained interest as a strategy for greenhouse gas emission reductions, energy security, and economic advantage. Biodiesel adoption may also reduce particulate elemental carbon (EC) emissions from conventional diesel engines that are not equipped with after-treatment devices. This study examines the impact of biodiesel blends on EC emissions from a commercial off-road diesel engine and simulates the potential public health benefits and climate benefits. EC emissions from the commercial off-road engine decreased by 76% when ultra-low sulfur commercial diesel (ULSD) fuel was replaced by biodiesel. Model calculations predict that reduced EC emissions translate directly into reduced EC concentrations in the atmosphere, but the concentration of secondary particulate matter was not directly affected by this fuel change. Redistribution of secondary particulate matter components to particles emitted from other sources did change the size distribution and therefore deposition rates of those components. Modification of meteorological variables such as water content and temperature influenced secondary particulate matter formation. Simulations with a source-oriented WRF/Chem model (SOWC) for a severe air pollution episode in California that adopted 75% biodiesel blended with ULSD in all non-road diesel engines reduced surface EC concentrations by up to 50% but changed nitrate and total PM2.5 mass concentrations by less than ±5%. These changes in concentrations will have public health benefits but did not significantly affect radiative forcing at the top of the atmosphere. The removal of EC due to the adoption of biodiesel produced larger coatings of secondary particulate matter on other atmospheric particles containing residual EC leading to enhanced absorption associated with those particles. The net effect was a minor change in atmospheric optical properties despite a large change in atmospheric EC

  5. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2008-11-01

    Full Text Available We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS, a proton transfer reaction mass spectrometer (PTR-MS, and a thermal desorption aerosol GC-MS (TAG – and found to be abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO, a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg−1h−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  6. Atmospheric impacts of black carbon emission reductions through the strategic use of biodiesel in California.

    Science.gov (United States)

    Zhang, Hongliang; Magara-Gomez, Kento T; Olson, Michael R; Okuda, Tomoaki; Walz, Kenneth A; Schauer, James J; Kleeman, Michael J

    2015-12-15

    The use of biodiesel as a replacement for petroleum-based diesel fuel has gained interest as a strategy for greenhouse gas emission reductions, energy security, and economic advantage. Biodiesel adoption may also reduce particulate elemental carbon (EC) emissions from conventional diesel engines that are not equipped with after-treatment devices. This study examines the impact of biodiesel blends on EC emissions from a commercial off-road diesel engine and simulates the potential public health benefits and climate benefits. EC emissions from the commercial off-road engine decreased by 76% when ultra-low sulfur commercial diesel (ULSD) fuel was replaced by biodiesel. Model calculations predict that reduced EC emissions translate directly into reduced EC concentrations in the atmosphere, but the concentration of secondary particulate matter was not directly affected by this fuel change. Redistribution of secondary particulate matter components to particles emitted from other sources did change the size distribution and therefore deposition rates of those components. Modification of meteorological variables such as water content and temperature influenced secondary particulate matter formation. Simulations with a source-oriented WRF/Chem model (SOWC) for a severe air pollution episode in California that adopted 75% biodiesel blended with ULSD in all non-road diesel engines reduced surface EC concentrations by up to 50% but changed nitrate and total PM2.5 mass concentrations by less than ±5%. These changes in concentrations will have public health benefits but did not significantly affect radiative forcing at the top of the atmosphere. The removal of EC due to the adoption of biodiesel produced larger coatings of secondary particulate matter on other atmospheric particles containing residual EC leading to enhanced absorption associated with those particles. The net effect was a minor change in atmospheric optical properties despite a large change in atmospheric EC

  7. Ocean versus atmosphere control on western European wintertime temperature variability

    Science.gov (United States)

    Yamamoto, Ayako; Palter, Jaime B.; Lozier, M. Susan; Bourqui, Michel S.; Leadbetter, Susan J.

    2015-12-01

    Using a novel Lagrangian approach, we assess the relative roles of the atmosphere and ocean in setting interannual variability in western European wintertime temperatures. We compute sensible and latent heat fluxes along atmospheric particle trajectories backtracked in time from four western European cities, using a Lagrangian atmospheric dispersion model driven with meteorological reanalysis data. The material time rate of change in potential temperature and the surface turbulent fluxes computed along the trajectory show a high degree of correlation, revealing a dominant control of ocean-atmosphere heat and moisture exchange in setting heat flux variability for atmospheric particles en route to western Europe. We conduct six idealised simulations in which one or more aspects of the climate system is held constant at climatological values and these idealised simulations are compared with a control simulation, in which all components of the climate system vary realistically. The results from these idealised simulations suggest that knowledge of atmospheric pathways is essential for reconstructing the interannual variability in heat flux and western European wintertime temperature, and that variability in these trajectories alone is sufficient to explain at least half of the internannual flux variability. Our idealised simulations also expose an important role for sea surface temperature in setting decadal scale variability of air-sea heat fluxes along the Lagrangian pathways. These results are consistent with previous studies showing that air-sea heat flux variability is driven by the atmosphere on interannual time scales over much of the North Atlantic, whereas the SST plays a leading role on longer time scales. Of particular interest is that the atmospheric control holds for the integrated fluxes along 10-day back trajectories from western Europe on an interannual time scale, despite that many of these trajectories pass over the Gulf Stream and its North Atlantic

  8. The Role of Temporal Evolution in Modeling Atmospheric Emissions from Tropical Fires

    Science.gov (United States)

    Marlier, Miriam E.; Voulgarakis, Apostolos; Shindell, Drew T.; Faluvegi, Gregory S.; Henry, Candise L.; Randerson, James T.

    2014-01-01

    Fire emissions associated with tropical land use change and maintenance influence atmospheric composition, air quality, and climate. In this study, we explore the effects of representing fire emissions at daily versus monthly resolution in a global composition-climate model. We find that simulations of aerosols are impacted more by the temporal resolution of fire emissions than trace gases such as carbon monoxide or ozone. Daily-resolved datasets concentrate emissions from fire events over shorter time periods and allow them to more realistically interact with model meteorology, reducing how often emissions are concurrently released with precipitation events and in turn increasing peak aerosol concentrations. The magnitude of this effect varies across tropical ecosystem types, ranging from smaller changes in modeling the low intensity, frequent burning typical of savanna ecosystems to larger differences when modeling the short-term, intense fires that characterize deforestation events. The utility of modeling fire emissions at a daily resolution also depends on the application, such as modeling exceedances of particulate matter concentrations over air quality guidelines or simulating regional atmospheric heating patterns.

  9. Influence of daily versus monthly fire emissions on atmospheric model applications in the tropics

    Science.gov (United States)

    Marlier, M. E.; Voulgarakis, A.; Faluvegi, G.; Shindell, D. T.; DeFries, R. S.

    2012-12-01

    Fires are widely used throughout the tropics to create and maintain areas for agriculture, but are also significant contributors to atmospheric trace gas and aerosol concentrations. However, the timing and magnitude of fire activity can vary strongly by year and ecosystem type. For example, frequent, low intensity fires dominate in African savannas whereas Southeast Asian peatland forests are susceptible to huge pulses of emissions during regional El Niño droughts. Despite the potential implications for modeling interactions with atmospheric chemistry and transport, fire emissions have commonly been input into global models at a monthly resolution. Recognizing the uncertainty that this can introduce, several datasets have parsed fire emissions to daily and sub-daily scales with satellite active fire detections. In this study, we explore differences between utilizing the monthly and daily Global Fire Emissions Database version 3 (GFED3) products as inputs into the NASA GISS-E2 composition climate model. We aim to understand how the choice of the temporal resolution of fire emissions affects uncertainty with respect to several common applications of global models: atmospheric chemistry, air quality, and climate. Focusing our analysis on tropical ozone, carbon monoxide, and aerosols, we compare modeled concentrations with available ground and satellite observations. We find that increasing the temporal frequency of fire emissions from monthly to daily can improve correlations with observations, predominately in areas or during seasons more heavily affected by fires. Differences between the two datasets are more evident with public health applications: daily resolution fire emissions increases the number of days exceeding World Health Organization air quality targets.

  10. High resolution of anthropogenic atmospheric emissions of 12 heavy metals in the three biggest metropolitan areas, China

    Science.gov (United States)

    Tian, H.; Zhu, C.

    2015-12-01

    Atmospheric emissions of typical toxic heavy metals from anthropogenic sources have received worldwide concerns due to their adverse effects on human health and the ecosystem. An integrated inventory of anthropogenic emissions of twelve HMs (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu and Zn) in the three biggest metropolitan areas, including Beijing-Tianjin-Hebei (BTH) region, Yangtze River Delta (YRD) region and Pearl River Delta (PRD) region, are developed for 1980-2012 by combining with detailed activity data and inter-annual dynamic emission factors which are determined by S-shaped curves on account of technology progress, economic development, and emission control. The results indicate total emissions of twelve HMs in the three metropolitan regions have increased from 5448.8 tons in 1980 to 19054.9 tons in 2012, with an annual average growth rate of about 4.0%. Due to significant difference in industrial structures and energy consumption compositions, remarkable distinctions can be observed with respect to source contributions of total HM emissions from above three metropolitan areas. Specifically, the ferrous metal smelting sector, coal combustion by industrial boilers and coal combustion by power plants are found to be the primary source of total HM emissions in the BTH region (about 34.2%), YRD region (about 28.2%) and PRD region (about 24.3%), respectively. Furthermore, we allocate the annual emissions of these heavy metals in 2012 at a high spatial resolution of 9 km × 9 km grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). The peak of HM emissions are mainly distributed over the grid cells of Beijing, Tianjin, Tangshan, Shijiazhuang, Handan and Baoding in the BTH region; Shanghai, Suzhou, Wuxi, Nanjing, Hangzhou, Ningbo in the YRD region; Guangzhou, Shenzhen, Dongguan, Foshan in the PYD region, respectively. Additionally, monthly emission profiles are established in order to further identify

  11. Comparison of emissions estimates derived from atmospheric measurements with national estimates of HFCs, PFCs and SF6.

    Science.gov (United States)

    Harnisch, Jochen; Höhne, Niklas

    2002-01-01

    This paper assesses the feasibility of using atmospheric measurement of fluorinated greenhouse gases (HFCs, PFCs and SF6) for the review and verification of greenhouse gas inventories provided by national governments. For this purpose, available data were compiled. It was found that atmospheric measurements of these gases are available and provide an indication of global annual emissions with sufficient certainty to reach the following conclusions: Within the uncertainty of the method, it was found that emissions of HFC-23, a by-product of HCFC-22 production, as obtained from atmospheric measurements did not decrease as fast, as the countries have reported. In contrast, SF6 concentrations in the atmosphere suggest higher emissions than reported by countries. Regional emission estimates from atmospheric measurements are still in a more pioneering state and cannot be compared to national estimates. Intensified efforts to measure HFCs, PFCs and SF6 in the atmosphere are recommended. PMID:12391806

  12. Modeling angular-dependent spectral emissivity of snow and ice in the thermal infrared atmospheric window.

    Science.gov (United States)

    Hori, Masahiro; Aoki, Teruo; Tanikawa, Tomonori; Hachikubo, Akihiro; Sugiura, Konosuke; Kuchiki, Katsuyuki; Niwano, Masashi

    2013-10-20

    A model of angular-dependent emissivity spectra of snow and ice in the 8-14 μm atmospheric window is constructed. Past field research revealed that snow emissivity varies depending on snow grain size and the exitance angle. Thermography images acquired in this study further revealed that not only welded snow particles such as sun crust, but also disaggregated particles such as granular snow and dendrite crystals exhibit high reflectivity on their crystal facets, even when the bulk snow surface exhibits blackbody-like behavior as a whole. The observed thermal emissive behaviors of snow particles suggest that emissivity of the bulk snow surface can be expressed by a weighted sum of two emissivity components: those of the specular and blackbody surfaces. Based on this assumption, a semi-empirical emissivity model was constructed; it is expressed by a linear combination of specular and blackbody surfaces' emissivities with a weighting parameter characterizing the specularity of the bulk surface. Emissivity spectra calculated using the model succeeded in reproducing the past in situ measured directional spectra of various snow types by employing a specific weighting parameter for each snow type.

  13. Atmospheric emissions from vegetation fires in Portugal (1990–2008: estimates, uncertainty analysis, and sensitivity analysis

    Directory of Open Access Journals (Sweden)

    J. M. C. Pereira

    2010-09-01

    Full Text Available Atmospheric emissions from wildfires in Portugal were estimated yearly over the period 1990–2008 using Landsat-based burnt area maps and land cover maps, national forest inventory data, biometric models, and literature review data. Emissions were calculated as the product of area burnt, biomass loading per unit area, combustion factor, and emission factor, using land cover specific values for all variables. Uncertainty associated with each input variable was quantified with a probability density function or a standard deviation value. Uncertainty and sensitivity analysis of estimates were performed with Monte Carlo and variance decomposition techniques. Area burnt varied almost 50-fold during the study period, from about 9000 ha in 2008 to 440 000 ha in 2003. Emissions reach maximum and minimum in the same years, with CO2eq values of 159 and 5655 Gg for 2008 and 2003, respectively. Emission factors, and the combustion factor for shrubs were identified as the variables with higher impact on model output variance. There is a very strong correlation between area burnt and emissions, allowing for accurate emissions estimates once area burnt is quantified. Pyrogenic emissions were compared against those from various economy sectors and found to represent 1% to 9% of the total.

  14. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    Science.gov (United States)

    Pirrone, N.; Cinnirella, S.; Feng, X.; Finkelman, R. B.; Friedli, H. R.; Leaner, J.; Mason, R.; Mukherjee, A. B.; Stracher, G. B.; Streets, D. G.; Telmer, K.

    2010-07-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr-1), artisanal small scale gold mining (400 Mg yr-1), non-ferrous metals manufacturing (310 Mg yr-1), cement production (236 Mg yr-1), waste disposal (187 Mg yr-1) and caustic soda production (163 Mg yr-1). Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions + re-emissions) and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  15. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    Directory of Open Access Journals (Sweden)

    N. Pirrone

    2010-07-01

    Full Text Available This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr−1, artisanal small scale gold mining (400 Mg yr−1, non-ferrous metals manufacturing (310 Mg yr−1, cement production (236 Mg yr−1, waste disposal (187 Mg yr−1 and caustic soda production (163 Mg yr−1. Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions + re-emissions and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  16. Modeling angular-dependent spectral emissivity of snow and ice in the thermal infrared atmospheric window.

    Science.gov (United States)

    Hori, Masahiro; Aoki, Teruo; Tanikawa, Tomonori; Hachikubo, Akihiro; Sugiura, Konosuke; Kuchiki, Katsuyuki; Niwano, Masashi

    2013-10-20

    A model of angular-dependent emissivity spectra of snow and ice in the 8-14 μm atmospheric window is constructed. Past field research revealed that snow emissivity varies depending on snow grain size and the exitance angle. Thermography images acquired in this study further revealed that not only welded snow particles such as sun crust, but also disaggregated particles such as granular snow and dendrite crystals exhibit high reflectivity on their crystal facets, even when the bulk snow surface exhibits blackbody-like behavior as a whole. The observed thermal emissive behaviors of snow particles suggest that emissivity of the bulk snow surface can be expressed by a weighted sum of two emissivity components: those of the specular and blackbody surfaces. Based on this assumption, a semi-empirical emissivity model was constructed; it is expressed by a linear combination of specular and blackbody surfaces' emissivities with a weighting parameter characterizing the specularity of the bulk surface. Emissivity spectra calculated using the model succeeded in reproducing the past in situ measured directional spectra of various snow types by employing a specific weighting parameter for each snow type. PMID:24216578

  17. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    Directory of Open Access Journals (Sweden)

    N. Pirrone

    2010-02-01

    Full Text Available This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial point sources, are estimated to account for 2320 Mg of mercury emitted annually. The major contributions are from fossil-fuel fired power plants (810 Mg yr−1, artisanal small scale gold mining (400 Mg yr−1, non-ferrous metals manufacturing (310 Mg yr−1, cement production (236 Mg yr−1, waste disposal (187 Mg yr−1 and caustic soda production (163 Mg yr−1. Therefore, our current estimate of global mercury emissions suggests that the overall contribution from natural sources (primary emissions+re-emissions and anthropogenic sources is nearly 7527 Mg per year, the uncertainty associated with these estimates are related to the typology of emission sources and source regions.

  18. Emissions from pre-Hispanic metallurgy in the South American atmosphere.

    Science.gov (United States)

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA.

  19. Simultaneous measurements of atmospheric emissions at 10, 33 and 90 GHz

    International Nuclear Information System (INIS)

    As part of a larger experiment to measure the cosmic microwave background radiation spectrum, frequent simultaneous measurements of the microwave thermal emission from the earth's atmosphere were made at three fixed frequencies, namely, 10 GHz, 33 GHz and 90 GHz. We performed these measurements at two separate locations, Berkeley and White Mountain, which greatly differed in altitude and climatic conditions. Typical values measured in Berkeley of the atmospheric antenna temperature during good weather are 3.13 +- 0.300K, 12.3 +- 0.30K and 34.6 +- 0.50K, for 10, 33, and 90 GHz respectively. Corresponding values measured at White Mountain are 1.15 +- 0.10K, 4.51 +- 0.180K and 11.0 +- 0.20K. Because the measurements are simultaneous in nature, correlations between the measurements taken at the various frequencies provide constraints on models of the microwave emission of the earth's atmosphere, especially models describing atmospheric emission as a function of precipitable water content

  20. The ENSO signal in atmospheric composition fields: emission driven vs. dynamically induced changes

    Directory of Open Access Journals (Sweden)

    A. Inness

    2015-05-01

    Full Text Available The El Niño Southern Oscillation (ENSO does not only affect meteorological fields but also has a large impact on atmospheric composition. Atmospheric composition fields from the Monitoring Atmospheric Composition and Climate (MACC reanalysis are used to identify the ENSO signal in tropospheric ozone, carbon monoxide, nitrogen oxide and smoke aerosols, concentrating on the months October to December. During El Niño years all these fields have increased concentrations over maritime South East Asia in October. The MACC Composition Integrated Forecasting System (C-IFS model is used to quantify the relative magnitude of dynamically induced and emission driven changes in the atmospheric composition fields. While changes in tropospheric ozone are a combination of dynamically induced and emission driven changes, the changes in carbon monoxide, nitrogen oxide and smoke aerosols are almost entirely emission driven in the MACC model. The ozone changes continue into December, i.e. after the end of the Indonesian fire season while changes in the other fields are confined to the fire season.

  1. Case study of the atmospheric dispersion of emissions from UPPR/CDTN, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Alberto A.; Cesar, Raisa H.S.; Maleta, Paulo G.M.; Grossi, Pablo A., E-mail: aab@cdtn.br, E-mail: raisa.hsc@gmail.com, E-mail: pgmm@cdtn.br, E-mail: pablo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    This work presents a study of the atmospheric dispersion of emissions released during activities of production and research of radiopharmaceuticals in the Center of Nuclear Technology Development (CDTN), localized in Belo Horizonte, Minas Gerais - Brazil. The installation, 'Unidade de Producao e Pesquisa de Radiofarmacos' (UPPR), was considered operating full time during a year. The general goal was to evaluate the radiological environmental impact due to these atmospheric emissions. The pollutants studied were the radionuclides F-18, C-11 and N-13. The meteorological view evaluated was a period of 365 days, simulated from the dates of a typical meteorological year. It was applied the dispersion model ARTM (Atmospheric Radionuclide Transport Model). The atmospheric emissions from UPPR were estimated for the simulation based in an extremely conservative operation condition. Others important data raised and analyzed were: topography, obstacles (buildings) and the land occupation around the CDTN. Among the main results, it is important to emphasize the estimate of the radionuclide concentration and the dose value calculated from these concentration. These results were compared with the dose restriction limit set by the standard CNEN 3.01. Areas of higher concentration were identified and are being used as reference for the positioning of the concentration's monitor of the pollutant by the Radiological Environmental Monitoring Program (PMA). (author)

  2. Emissions from pre-Hispanic metallurgy in the South American atmosphere.

    Directory of Open Access Journals (Sweden)

    François De Vleeschouwer

    Full Text Available Metallurgical activities have been undertaken in northern South America (NSA for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA.

  3. Intensity and polarization of the atmospheric emission at millimetric wavelengths at Dome Concordia

    CERN Document Server

    Battistelli, E S; Baù, A; Bergé, L; Bréelle, É; Charlassier, R; Collin, S; Cruciani, A; de Bernardis, P; Dufour, C; Dumoulin, L; Gervasi, M; Giard, M; Giordano, C; Giraud-Héraud, Y; Guglielmi, L; Hamilton, J -C; Landé, J; Maffei, B; Maiello, M; Marnieros, S; Masi, S; Passerini, A; Piacentini, F; Piat, M; Piccirillo, L; Pisano, G; Polenta, G; Rosset, C; Salatino, M; Schillaci, A; Sordini, R; Spinelli, S; Tartari, A; Zannoni, M

    2012-01-01

    Atmospheric emission is a dominant source of disturbance in ground-based astronomy at mm wavelengths. The Antarctic plateau is recognized to be an ideal site for mm and sub-mm observations, and the French/Italian base of Dome C is among the best sites on Earth for these observations. In this paper we present measurements, performed using the BRAIN-pathfinder experiment, at Dome C of the atmospheric emission in intensity and polarization at 150GHz, one of the best observational frequencies for CMB observations when considering cosmic signal intensity, atmospheric transmission, detectors sensitivity, and foreground removal. Careful characterization of the air-mass synchronous emission has been performed, acquiring more that 380 elevation scans (i.e. "skydip") during the third BRAIN-pathfinder summer campaign in December 2009/January 2010. The extremely high transparency of the Antarctic atmosphere over Dome Concordia is proven by the very low measured optical depth: =0.050 \\pm 0.003 \\pm 0.011 where the first er...

  4. Control of aggregation-induced emission by DNA hybridization

    OpenAIRE

    Li, Shaoguang; Langenegger, Simon Matthias; Häner, Robert

    2013-01-01

    Aggregation-induced emission (AIE) was studied by hybridization of dialkynyl-tetraphenylethylene (DATPE) modified DNA strands. Molecular aggregation and fluorescence of DATPEs are controlled by duplex formation.

  5. Increased soil emissions of potent greenhouse gases under increased atmospheric CO2.

    Science.gov (United States)

    van Groenigen, Kees Jan; Osenberg, Craig W; Hungate, Bruce A

    2011-07-13

    Increasing concentrations of atmospheric carbon dioxide (CO(2)) can affect biotic and abiotic conditions in soil, such as microbial activity and water content. In turn, these changes might be expected to alter the production and consumption of the important greenhouse gases nitrous oxide (N(2)O) and methane (CH(4)) (refs 2, 3). However, studies on fluxes of N(2)O and CH(4) from soil under increased atmospheric CO(2) have not been quantitatively synthesized. Here we show, using meta-analysis, that increased CO(2) (ranging from 463 to 780 parts per million by volume) stimulates both N(2)O emissions from upland soils and CH(4) emissions from rice paddies and natural wetlands. Because enhanced greenhouse-gas emissions add to the radiative forcing of terrestrial ecosystems, these emissions are expected to negate at least 16.6 per cent of the climate change mitigation potential previously predicted from an increase in the terrestrial carbon sink under increased atmospheric CO(2) concentrations. Our results therefore suggest that the capacity of land ecosystems to slow climate warming has been overestimated.

  6. Emission to atmosphere of tritiated water formed at soil surface by oxidation of HT

    International Nuclear Information System (INIS)

    In the event of a release of molecular tritium to atmosphere, some tritium can oxidized at soil surface and be gradually re-emitted to atmosphere as HTO. The two processes are characterized by a deposition velocity and an emission rate, which are commonly used in deposition/emission models designed to calculate the concentrations of HTO in atmosphere. A technique has been developed to determine the emission rate and its evolution, by covering a small area of undisturbed soil by a field chamber, exposing the enclosed soil to molecular tritium, then determining the changes in HTO vapour content of a measured air-stream passing through the chamber. The emission rate is derived by dividing the amount of HTO extracted from the chamber during a given period of time, by the average amount of HTO contained in the soil during the same period. First experiments have been done on bare and grass-covered soils. The data obtained from these small-scale field experiments are consistent with those obtained from a full-scale field study carried out at nearly the same place

  7. Dark-to-arc transition in field emission dominated atmospheric microdischarges

    Energy Technology Data Exchange (ETDEWEB)

    Tholeti, Siva Sashank [School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907 (United States); Semnani, Abbas; Peroulis, Dimitrios [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Alexeenko, Alina A., E-mail: alexeenk@purdue.edu [School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)

    2015-08-15

    We study the voltage-current characteristics of gas discharges driven by field emission of electrons at the microscale. Particle-in-cell with Monte Carlo collision calculations are first verified by comparison with breakdown voltage measurements and then used to investigate atmospheric discharges in nitrogen at gaps from 1 to 10 μm. The results indicate the absence of the classical glow discharge regime because field electron emission replaces secondary electron emission as the discharge sustaining mechanism. Additionally, the onset of arcing is significantly delayed due to rarefied effects in electron transport. While field emission reduces the breakdown voltage, the power required to sustain an arc of the same density in microgaps is as much as 30% higher than at macroscale.

  8. Current status and prediction of major atmospheric emissions from coal-fired power plants in Shandong Province, China

    Science.gov (United States)

    Xiong, Tianqi; Jiang, Wei; Gao, Weidong

    2016-01-01

    Shandong is considered to be the top provincial emitter of air pollutants in China due to its large consumption of coal in the power sector and its dense distribution of coal-fired plants. To explore the atmospheric emissions of the coal-fired power sector in Shandong, an updated emission inventory of coal-fired power plants for the year 2012 in Shandong was developed. The inventory is based on the following parameters: coal quality, unit capacity and unit starting year, plant location, boiler type and control technologies. The total SO2, NOx, fine particulate matter (PM2.5) and mercury (Hg) emissions are estimated at 705.93 kt, 754.30 kt, 63.99 kt and 10.19 kt, respectively. Larger units have cleaner emissions than smaller ones. The coal-fired units (≥300 MW) are estimated to account for 35.87% of SO2, 43.24% of NOx, 47.74% of PM2.5 and 49.83% of Hg emissions, which is attributed primarily to the improved penetration of desulfurization, LNBs, denitration and dust-removing devices in larger units. The major regional contributors are southwestern cities, such as Jining, Liaocheng, Zibo and Linyi, and eastern cities, such as Yantai and Qindao. Under the high-efficiency control technology (HECT) scenario analysis, emission reductions of approximately 58.61% SO2, 80.63% NOx, 34.20% PM2.5 and 50.08% Hg could be achieved by 2030 compared with a 2012 baseline. This inventory demonstrates why it is important for policymakers and researchers to assess control measure effectiveness and to supply necessary input for regional policymaking and the management of the coal-fired power sector in Shandong.

  9. Emissions control for ground power gas turbines

    Science.gov (United States)

    Rudney, R. A.; Priem, R. J.; Juhasz, A. J.; Anderson, D. N.; Mroz, T. S.; Mularz, E. J.

    1977-01-01

    The similarities and differences of emissions reduction technology for aircraft and ground power gas turbines is described. The capability of this technology to reduce ground power emissions to meet existing and proposed emissions standards is presented and discussed. Those areas where the developing aircraft gas turbine technology may have direct application to ground power and those areas where the needed technology may be unique to the ground power mission are pointed out. Emissions reduction technology varying from simple combustor modifications to the use of advanced combustor concepts, such as catalysis, is described and discussed.

  10. A comparative analysis of two highly spatially resolved European atmospheric emission inventories

    Science.gov (United States)

    Ferreira, J.; Guevara, M.; Baldasano, J. M.; Tchepel, O.; Schaap, M.; Miranda, A. I.; Borrego, C.

    2013-08-01

    A reliable emissions inventory is highly important for air quality modelling applications, especially at regional or local scales, which require high resolutions. Consequently, higher resolution emission inventories have been developed that are suitable for regional air quality modelling. This research performs an inter-comparative analysis of different spatial disaggregation methodologies of atmospheric emission inventories. This study is based on two different European emission inventories with different spatial resolutions: 1) the EMEP (European Monitoring and Evaluation Programme) inventory and 2) an emission inventory developed by the TNO (Netherlands Organisation for Applied Scientific Research). These two emission inventories were converted into three distinct gridded emission datasets as follows: (i) the EMEP emission inventory was disaggregated by area (EMEParea) and (ii) following a more complex methodology (HERMES-DIS - High-Elective Resolution Modelling Emissions System - DISaggregation module) to understand and evaluate the influence of different disaggregation methods; and (iii) the TNO gridded emissions, which are based on different emission data sources and different disaggregation methods. A predefined common grid with a spatial resolution of 12 × 12 km2 was used to compare the three datasets spatially. The inter-comparative analysis was performed by source sector (SNAP - Selected Nomenclature for Air Pollution) with emission totals for selected pollutants. It included the computation of difference maps (to focus on the spatial variability of emission differences) and a linear regression analysis to calculate the coefficients of determination and to quantitatively measure differences. From the spatial analysis, greater differences were found for residential/commercial combustion (SNAP02), solvent use (SNAP06) and road transport (SNAP07). These findings were related to the different spatial disaggregation that was conducted by the TNO and HERMES

  11. Emission spectroscopy of an atmospheric pressure plasma jet operated with air at low frequency

    Science.gov (United States)

    Giuliani, L.; Gallego, J. L.; Minotti, F.; Kelly, H.; Grondona, D.

    2015-03-01

    Low-temperature, high-pressure plasma jets have an extensive use in plasma biology and plasma medicine, such as pathogen deactivation, wound disinfection, stopping of bleeding without damage of healthy tissue, acceleration of wound healing, control of bio-film proliferation, etc. In this work, a spectroscopic characterization of a typical plasma jet, operated in air at atmospheric pressure, is reported. Within the spectrum of wavelengths from 200 to 450 nm all remarkable emissions of N2 were monitored. Spectra of the N2 2nd positive system (C3Πu-B3Πg) emitted in air are the most convenient for plasma diagnostics, since they enable to determine electronic Te, rotational Tr and vibrational Tv temperatures by fitting the experimental spectra with the simulated ones. We used SPECAIR software for spectral simulation and obtained the best fit with all these temperatures about 3500K. The conclusion that all temperatures are equal, and its relatively high value, is consistent with the results of a previous work, where it was found that the experimentally determined electrical characteristic was consistent with the model of a thermal arc discharge, together with a highly collisional cathode sheet.

  12. Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

    Directory of Open Access Journals (Sweden)

    Barthelemy Mathieu

    2014-01-01

    Full Text Available The solar UV (UltraViolet flux, especially the EUV (Extreme UltraViolet and FUV (Far UltraViolet components, is one of the main energetic inputs for planetary upper atmospheres. It drives various processes such as ionization, or dissociation which give rise to upper atmospheric emissions, especially in the UV and visible. These emissions are one of the main ways to investigate the upper atmospheres of planets. However, the uncertainties in the flux measurement or modeling can lead to biased estimates of fundamental atmospheric parameters, such as concentrations or temperatures in the atmospheres. We explore the various problems that can be identified regarding the uncertainties in solar/stellar UV flux by considering three examples. The worst case appears when the solar reflection component is dominant in the recorded spectrum as is seen for outer solar system measurements from HST (Hubble Space Telescope. We also show that the estimation of some particular line parameters (intensity and shape, especially Lyman α, is crucial, and that both total intensity and line profile are useful. In the case of exoplanets, the problem is quite critical since the UV flux of their parent stars is often very poorly known.

  13. Temporal Evolution and Atmospheric Impacts of Tropospheric Volcanic Emissions from In-Situ Measurements and Modelling

    Science.gov (United States)

    Roberts, Tjarda

    2010-05-01

    Assessment of the impact of tropospheric volcanic gas and aerosol emissions requires integration of observation and modelling. Knowledge and understanding is rapidly advancing in both areas, particularly due to the development of kinetic plume models of reactive halogen chemistry, and due to recent advances in measurement techniques for collecting in situ measurements of plume physico-chemical properties (i.e. using meteorological balloon and aircraft platforms), as well as a proliferation of remote sensing DOAS measurements. Here, we demonstrate this synergic relationship through model-observation plume studies. Volcanoes are a large natural source of SO2 and sulphate to the atmosphere, as is well demonstrated from both observational and model studies. In a recent study that deployed quasi-Lagrangian balloons in emissions at Kilauea volcano, Hawaii, both H2O(g) and SO2(g) were measured in situ, in the downwind plume. The observations showed periods of both correlation and anti-correlation between SO2 and water-vapour, implying the occurrence of both source and sink processes. Co-emission of volcanic H2O with SO2 accounts for the correlation. We use a thermodynamic model along the plume transect to assess how H2O-sulphate interactions might account for H2O anti-correlation with SO2 within the plume to elucidate in-plume sulphate formation, both near-vent (as predicted by high-T thermodynamic models) and downwind (as predicted by kinetic models). Volcanoes are a source of halogens (HBr, HCl) to the atmosphere, and volcanic plumes are highly reactive zones, not only in the high-temperature region near the vent, but also in the downwind plume where autocatalytic chemistry cycles produce reactive halogens such as BrO, first discovered from DOAS observations. The rapid formation of BrO can be reproduced through modelling which predicts high concentrations (reaching ppbv) on short formation timescales (minutes). Simulations using the PlumeChem model (developed to analyse

  14. Analysis of atmospheric aerosols by atomic emission spectrometry with electrical discharge sampling

    International Nuclear Information System (INIS)

    A procedure is developed for the determination of the concentration of heavy metals (Pb, Mn, Cu, Ni, Zn, and Cd) in atmospheric air by atomic emission spectrometry with gas-discharge sampling onto the end of a standard carbon electrode. A design of a two-section sampler is proposed; the sampler provides the rapid determination of deposition factors for the deposition of heavy metals contained in aerosol particles onto the end of a carbon electrode. Examples of determining metal concentrations in a model sample of air and in atmospheric air and determination limits of metals deposited onto the end of a carbon electrode are given

  15. Improved controlled atmosphere high temperature scanning probe microscope

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Wu, Yuehua; Jacobsen, Torben;

    2013-01-01

    fuel cells and electrolyzer cells. Here, we report on advanced improvements of our original controlled atmosphere high temperature scanning probe microscope, CAHT-SPM. The new microscope can employ a broad range of the scanning probe techniques including tapping mode, scanning tunneling microscopy...

  16. 49 CFR 192.479 - Atmospheric corrosion control: General.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Atmospheric corrosion control: General. 192.479 Section 192.479 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY...

  17. A Reversal of Long-term Global Trends in Atmospheric Ethane and Propane from North American Oil and Natural Gas Emissions

    OpenAIRE

    Helmig, D.; Rossabi, S.; J. Hueber; P. P. Tans; Montzka, S. A.; Mazarie, K.; Thoning, K.; C. Plass-Duelmer; Claude, A; Lewis, A. C.; L. J. Carpenter; Punjabi, S.; S. Reimann; M. K. Vollmer; R. Steinbrecher

    2016-01-01

    Ethane, the longest-lived and most abundant non-methane hydrocarbon (NMHC) peaked in the background atmosphere around 1970. This was followed by a ~20% reduction of the atmospheric burden and a resulting atmospheric downward trend for the next four decades, mostly due to reduced emissions from oil and gas industries and stricter air quality controls. Here, we show that the near 40-year trend of declining global ethane halted between 2005-2010 in most of the Northern Hemisphere (NH), and that ...

  18. 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.

  19. Environmental atmospheric impact assessment by the emission of particles in an industrial area

    International Nuclear Information System (INIS)

    The content of metals present in suspended particulate matter was evaluated using analytical related nuclear techniques, in order to discriminate the contribution of different emission sources to the atmospheric concentration in the area of Campana, located in the Province of Buenos Aires. The levels of Ti, V, Cr, Mn, Ni, Cu, Zn, Sr, Ag, Cd y Pb were quantified by Wave Dispersion X-Ray Florescence spectrometry (WDXRF), Total Reflection X-Ray Fluorescence spectrometry (TRXRF) and Inducted Coupled Plasma Absorption Emission spectroscopy (ICP-AES). (author)

  20. Process analysis of the modelled 3-D mesoscale impact of aircraft emissions on the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, J.; Ebel, A.; Lippert, E.; Petry, H. [Koeln Univ. (Germany). Inst. fuer Geophysik und Meterorologie

    1997-12-31

    A mesoscale chemistry transport model is applied to study the impact of aircraft emissions on the atmospheric trace gas composition. A special analysis of the simulations is conducted to separate the effects of chemistry, transport, diffusion and cloud processes on the transformation of the exhausts of a subsonic fleet cruising over the North Atlantic. The aircraft induced ozone production strongly depends on the tropopause height and the cruise altitude. Aircraft emissions may undergo an effective downward transport under the influence of stratosphere-troposphere exchange activity. (author) 12 refs.

  1. Stable atmospheric methane in the 2000s: key-role of emissions from natural wetlands

    Directory of Open Access Journals (Sweden)

    I. Pison

    2013-04-01

    Full Text Available Two atmospheric inversions (one fine-resolved and one process-discriminating and a process-based model for land surface exchanges are brought together to analyze the variations of methane emissions from 1990 to 2009. A focus is put on the role of natural wetlands and on the years 2000–2006, a period of stable atmospheric concentrations. From 1990 to 2000, the two inversions agree on the time-phasing of global emission anomalies. The process-discriminating inversion further indicates that wetlands dominate the time-variability of methane emissions with 90% of the total variability. Top-down and bottom-up methods are qualitatively in good agreement regarding the global emission anomalies. The contribution of tropical wetlands on these anomalies is found to be large, especially during the post-Pinatubo years (global negative anomalies with minima between −41 and −19 Tg y−1 in 1992 and during the alternate 1997–1998 el-Niño/1998–1999 la-Niña (maximal anomalies in tropical regions between +16 and +22 Tg y−1 for the inversions and anomalies due to tropical wetlands between +12 and +17 Tg y−1 for the process-based model. Between 2000 and 2006, during the stagnation of methane concentrations in the atmosphere, total methane emissions found by the two inversions on the one hand and wetland emissions found by the process-discriminating-inversion and the process model on the other hand are not fully consistent. A regional analysis shows that differences in the trend of tropical South American wetland emissions in the Amazon region are mostly responsible for these discrepancies. A negative trend (−3.9 ± 1.3 Tg y−1 is inferred by the process-discriminating inversion whereas a positive trend (+1.3 ± 0.3 Tg y−1 is found by the process model. Since a positive trend is consistent with satellite-derived extent of inundated areas, this inconsistency points at the difficulty for atmospheric inversions using surface observations to properly

  2. The impact of residential combustion emissions on atmospheric aerosol, human health, and climate

    Science.gov (United States)

    Butt, E. W.; Rap, A.; Schmidt, A.; Scott, C. E.; Pringle, K. J.; Reddington, C. L.; Richards, N. A. D.; Woodhouse, M. T.; Ramirez-Villegas, J.; Yang, H.; Vakkari, V.; Stone, E. A.; Rupakheti, M.; Praveen, P. S.; van Zyl, P. G.; Beukes, J. P.; Josipovic, M.; Mitchell, E. J. S.; Sallu, S. M.; Forster, P. M.; Spracklen, D. V.

    2016-01-01

    Combustion of fuels in the residential sector for cooking and heating results in the emission of aerosol and aerosol precursors impacting air quality, human health, and climate. Residential emissions are dominated by the combustion of solid fuels. We use a global aerosol microphysics model to simulate the impact of residential fuel combustion on atmospheric aerosol for the year 2000. The model underestimates black carbon (BC) and organic carbon (OC) mass concentrations observed over Asia, Eastern Europe, and Africa, with better prediction when carbonaceous emissions from the residential sector are doubled. Observed seasonal variability of BC and OC concentrations are better simulated when residential emissions include a seasonal cycle. The largest contributions of residential emissions to annual surface mean particulate matter (PM2.5) concentrations are simulated for East Asia, South Asia, and Eastern Europe. We use a concentration response function to estimate the human health impact due to long-term exposure to ambient PM2.5 from residential emissions. We estimate global annual excess adult (> 30 years of age) premature mortality (due to both cardiopulmonary disease and lung cancer) to be 308 000 (113 300-497 000, 5th to 95th percentile uncertainty range) for monthly varying residential emissions and 517 000 (192 000-827 000) when residential carbonaceous emissions are doubled. Mortality due to residential emissions is greatest in Asia, with China and India accounting for 50 % of simulated global excess mortality. Using an offline radiative transfer model we estimate that residential emissions exert a global annual mean direct radiative effect between -66 and +21 mW m-2, with sensitivity to the residential emission flux and the assumed ratio of BC, OC, and SO2 emissions. Residential emissions exert a global annual mean first aerosol indirect effect of between -52 and -16 mW m-2, which is sensitive to the assumed size distribution of carbonaceous emissions

  3. Estimating Sulfur hexafluoride (SF6) emissions in China using atmospheric observations and inverse modeling

    Science.gov (United States)

    Fang, X.; Thompson, R.; Saito, T.; Yokouchi, Y.; Li, S.; Kim, J.; Kim, K.; Park, S.; Graziosi, F.; Stohl, A.

    2013-12-01

    With a global warming potential of around 22800 over a 100-year time horizon, sulfur hexafluoride (SF6) is one of the greenhouse gases regulated under the Kyoto Protocol. Global SF6 emissions have been increasing since circa the year 2000. The reason for this increase has been inferred to be due to rapidly increasing emissions in developing countries that are not obligated to report their annual emissions to the United Nations Framework Convention on Climate Change, notably China. In this study, SF6 emissions during the period 2006-2012 for China and other East Asian countries were determined using in-situ atmospheric measurements and inverse modeling. We performed various inversion sensitivity tests, which show the largest uncertainties in the a posteriori Chinese emissions are associated with the a priori emissions used and their uncertainty, the station network, as well as the meteorological input data. The overall relative uncertainty of the a posteriori emissions in China is estimated to be 17% in 2008. Based on sensitivity tests, we employed the optimal parameters in our inversion setup and performed yearly inversions for the study period. Inversion results show that the total a posteriori SF6 emissions from China increased from 1420 × 245 Mg/yr in 2006 to 2741 × 472 Mg/yr in 2009 and stabilized thereafter. The rapid increase in emissions reflected a fast increase in SF6 consumption in China, a result also found in bottom-up estimates. The a posteriori emission map shows high emissions concentrated in populated parts of China. During the period 2006-2012, emissions in northwestern and northern China peaked around the year 2009, while emissions in eastern, central and northeastern China grew gradually during almost the whole period. Fluctuating emissions are observed for southwestern China. These regional differences should be caused by changes of provincial SF6 usage and by shifts of usage among different sectors. Fig. 1. Footprint emission sensitivity

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

    Energy Technology Data Exchange (ETDEWEB)

    BENKOVITZ,C.M.

    1997-09-01

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

  5. Atmospheric inversion for cost effective quantification of city CO2 emissions

    Directory of Open Access Journals (Sweden)

    L. Wu

    2015-11-01

    Full Text Available Cities, currently covering only a very small portion (2, and are associated with 71–76 % of CO2 emissions from global final energy use. Although many cities have set voluntary climate plans, their CO2 emissions are not evaluated by Monitoring, Reporting and Verification (MRV procedures that play a key role for market- or policy-based mitigation actions. Here we propose a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. We examine the cost-effectiveness and the performance of such a tool. The instruments presently used to measure CO2 concentrations at research stations are expensive. However, cheaper sensors are currently developed and should be useable for the monitoring of CO2 emissions from a megacity in the near-term. Our assessment of the inversion method is thus based on the use of several types of hypothetical networks, with a range of numbers of sensors sampling at 25 m a.g.l. The study case for this assessment is the monitoring of the emissions of the Paris metropolitan area (~ 12 million inhabitants and 11.4 Tg C emitted in 2010 during the month of January 2011. The performance of the inversion is evaluated in terms of uncertainties in the estimates of total and sectoral CO2 emissions. These uncertainties are compared to a notional ambitious target to diagnose annual total city emissions with an uncertainty of 5 % (2-sigma. We find that, with 10 stations only, which is the typical size of current pilot networks that are deployed in some cities, the uncertainty for the 1-month total city CO2 emissions is significantly reduced by the inversion by ~ 42 % but still corresponds to an annual uncertainty that is two times larger than the target of 5 %. By extending the network from 10 to

  6. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

    2000-02-26

    Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with

  7. Optimization of the inhibition of atmospheric window emission using photonic crystals

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Transfer matrix method is used to discuss the effect inhibition of photonic crystals on atmospheric window emission(ε-14 μm).According to the optical characteristics of the materials,germanium and zinc sulfide are used as the composing materials.The structure of the photonic crystals is optimized,and the optimal thickness values of the germanium and zinc sulfide are 0.63 and 1.11μm respectively while the ratio of optical thickness is 1:1 and the period is 8.The photonic crystals are prepared by evaporation coating method,and the optical properties of the photonic crystals are measured,the inhibition of the photonic crystals to atmospheric window emission is verified.

  8. Near-infrared thermal emissivity from ground based atmospheric dust measurements at ORM

    CERN Document Server

    Lombardi, G; Ortolani, S; Melnick, J; Ghedina, A; Garcia, A; Molinari, E; Gatica, C

    2011-01-01

    We present an analysis of the atmospheric content of aerosols measured at Observatorio del Roque de los Muchachos (ORM; Canary Islands). Using a laser diode particle counter located at the Telescopio Nazionale Galileo (TNG) we have detected particles of 0.3, 0.5, 1.0, 3.0, 5.0 and 10.0 um size. The seasonal behavior of the dust content in the atmosphere is calculated. The Spring has been found to be dustier than the Summer, but dusty conditions may also occur in Winter. A method to estimate the contribution of the aerosols emissivity to the sky brightness in the near-infrared (NIR) is presented. The contribution of dust emission to the sky background in the NIR has been found to be negligible comparable to the airglow, with a maximum contribution of about 8-10% in the Ks band in the dusty days.

  9. Microprocessor-controlled laser tracker for atmospheric sensing

    Science.gov (United States)

    Johnson, R. A.; Webster, C. R.; Menzies, R. T.

    1985-01-01

    An optical tracking system comprising a visible HeNe laser, an imaging detector, and a microprocessor-controlled mirror, has been designed to track a moving retroreflector located up to 500 m away from an atmospheric instrument and simultaneously direct spectrally tunable infrared laser radiation to the retroreflector for double-ended, long-path absorption measurements of atmospheric species. The tracker has been tested during the recent flight of a balloon-borne tunable diode laser absorption spectrometer which monitors the concentrations of stratospheric species within a volume defined by a 0.14-m-diameter retroreflector lowered 500 m below the instrument gondola.

  10. Implementing Strategies for Drying and Pressing Wood Without Emissions Controls

    Energy Technology Data Exchange (ETDEWEB)

    Sujit Banerjee; Terrance Conners

    2007-09-07

    Drying and pressing wood for the manufacture of lumber, particleboard, oriented strand board (OSB), veneer and medium density fiberboard (MDF) release volatile organic compounds (VOCs) into the atmosphere. These emissions require control equipment that are capital-intensive and consume significant quantities of natural gas and electricity. The objective of our work was to understand the mechanisms through which volatile organic compounds are generated and released and to develop simple control strategies. Of the several strategies developed, two have been implemented for OSB manufacture over the course of this study. First, it was found that increasing final wood moisture by about 2-4 percentage points reduced the dryer emissions of hazardous air pollutants by over 70%. As wood dries, the escaping water evaporatively cools the wood. This cooling tapers off wood when the wood is nearly dry and the wood temperature rises. Thermal breakdown of the wood tissue occurs and VOCs are released. Raising the final wood moisture by only a few percentage points minimizes the temperature rise and reduces emissions. Evaporative cooling also impacts has implications for VOC release from wood fines. Flaking wood for OSB manufacture inevitable generates fines. Fines dry out rapidly because of their high surface area and evaporative cooling is lost more rapidly than for flakes. As a result, fines emit a disproportionate quantity of VOCs. Fines can be reduced in two ways: through screening of the green furnish and through reducing their generation during flaking. The second approach is preferable because it also increased wood yield. A procedure to do this by matching the sharpness angle of the flaker knife to the ambient temperature was also developed. Other findings of practical interests are as follows: Dielectric heating of wood under low-headspace conditions removes terpenes and other extractives from softwood; The monoterpene content in trees depend upon temperature and seasonal

  11. Measurement and Control of Emission in Two Wheelers

    OpenAIRE

    Sarin K Kumar; Gaurav Saxena

    2014-01-01

    Vehicle emissions are a significant contributor to ambient pollution, especially in urban areas. In general, developing countries experience higher levels of traffic-related pollution compared to developed countries due to the lack of pollution control measures. Since numerous studies document adverse health effects from vehicle emission exposure, there is a need of developing some measures for the control of exhaust and non –exhaust emissions produced by the two wheelers. In ...

  12. Chloroform formation in Arctic and Subarctic soils - mechanism and emissions to the atmosphere

    Science.gov (United States)

    Albers, Christian N.; Johnsen, Anders R.; Jacobsen, Ole S.

    2015-04-01

    It is well established that halogenated organic compounds are formed naturally in the terrestrial environment. These compounds include volatiles such as trihalomethanes that may escape to the atmosphere. In deed most of the atmospheric chloroform (and other trihalomethane species) is regarded to have a natural origin. This origin may be both marine and terrestrial. Chloroform formation in soil has been reported in a number of studies, mostly conducted in temperate and (sub-) tropical environments. We hereby report that also colder soils emit chloroform naturally. We measured in situ the fluxes of chloroform from soil to atmosphere in 6 Subarctic and 5 Arctic areas covering different dwarf heath, wetland and forest biotopes in Greenland and Northern Sweden. Emissions were largest from the forested areas, but all areas emitted measurable amounts of chloroform. Also the brominated analog bromodichloromethane was formed in Arctic and Subarctic soils but the fluxes to the atmosphere were much lower than the corresponding chloroform emissions. No other volatile poly-halogenated organic compounds were found to be emitted from the study areas. It has previously been proposed that chloroform is formed in temperate forest soils through trichloroacetyl intermediates formed by unspecific enzymatic chlorination of soil organic matter. We found positive relationships between chloroform emissions and the concentration of trichloroacetyl groups in soil within the various biotopes. The hydrolysis of trichloroacetyl compounds is, however, very pH dependent, excluding a simple relationship between trichloroacetyl concentration and chloroform emission in any given soil. However, our results show that at low pH, turnover time of soil trichloroacetyl compounds may be counted in decades while at pH above 6, turnover time may be just a few months. We found no relationship between trichloroacetyl concentration and total organic chlorine concentration in the soils indicating that more than

  13. [Mercury Distribution Characteristics and Atmospheric Mercury Emission Factors of Typical Waste Incineration Plants in Chongqing].

    Science.gov (United States)

    Duan, Zhen-ya; Su, Hai-tao; Wang, Feng-yang; Zhang, Lei; Wang, Shu-xiao; Yu, Bin

    2016-02-15

    Waste incineration is one of the important atmospheric mercury emission sources. The aim of this article is to explore the atmospheric mercury pollution level of waste incineration industry from Chongqing. This study investigated the mercury emissions from a municipal solid waste incineration plant and a medical waste incineration plant in Chongqing. The exhaust gas samples in these two incineration plants were obtained using USA EPA 30B method. The mercury concentrations in the fly ash and bottom ash samples were analyzed. The results indicated that the mercury concentrations of the municipal solid waste and medical waste incineration plant in Chongqing were (26.4 +/- 22.7) microg x m(-3) and (3.1 +/- 0.8) microg x m(-3) in exhaust gas respectively, (5279.2 +/- 798.0) microg x kg(-1) and (11,709.5 +/- 460.5) microg x kg(-1) in fly ash respectively. Besides, the distribution proportions of the mercury content from municipal solid waste and medical waste in exhaust gas, fly ash, and bottom ash were 34.0%, 65.3%, 0.7% and 32.3%, 67.5%, 0.2% respectively; The mercury removal efficiencies of municipal solid waste and medical waste incineration plants were 66.0% and 67.7% respectively. The atmospheric mercury emission factors of municipal solid waste and medical waste incineration plants were (126.7 +/- 109.0) microg x kg(-1) and (46.5 +/- 12.0) microg x kg(-1) respectively. Compared with domestic municipal solid waste incineration plants in the Pearl River Delta region, the atmospheric mercury emission factor of municipal solid waste incineration plant in Chongqing was lower.

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

    OpenAIRE

    Jokinen, T; Berndt, T; Makkonen, R.; Kerminen, V-M; Junninen, H.; Paasonen, P.; Stratmann, F.; Herrmann, H.; Guenther, AB; Worsnop, DR; M. Kulmala; M. Ehn; Sipilä, M.

    2015-01-01

    Extremely low volatility organic compounds (ELVOC) are suggested to promote aerosol particle formation and cloud condensation nuclei (CCN) production in the atmosphere. We show that the capability of biogenic VOC (BVOC) to produce ELVOC depends strongly on their chemical structure and relative oxidant levels. BVOC with an endocyclic double bond, representative emissions from, e.g., boreal forests, efficiently produce ELVOC from ozonolysis. Compounds with exocyclic double bonds or acyclic comp...

  15. Atmospheric Emissions, Depositions, and Transformations of Arsenic in Natural Ecosystem in Finland

    OpenAIRE

    Mukherjee, Arun B.; Prosun Bhattacharya

    2002-01-01

    For the last 2 decades, special attention has been paid to arsenic due to its high concentration in groundwater in many regions of the globe. There are not very many reports on arsenic concentration in the Finnish ecosystem, although the metal has been known to be highly toxic since ancient times. For the majority of people in Finland, the leading exposure route to arsenic is through food consumption.In this study, it has been observed that atmospheric emissions of arsenic from anthropogenic ...

  16. [Mercury Distribution Characteristics and Atmospheric Mercury Emission Factors of Typical Waste Incineration Plants in Chongqing].

    Science.gov (United States)

    Duan, Zhen-ya; Su, Hai-tao; Wang, Feng-yang; Zhang, Lei; Wang, Shu-xiao; Yu, Bin

    2016-02-15

    Waste incineration is one of the important atmospheric mercury emission sources. The aim of this article is to explore the atmospheric mercury pollution level of waste incineration industry from Chongqing. This study investigated the mercury emissions from a municipal solid waste incineration plant and a medical waste incineration plant in Chongqing. The exhaust gas samples in these two incineration plants were obtained using USA EPA 30B method. The mercury concentrations in the fly ash and bottom ash samples were analyzed. The results indicated that the mercury concentrations of the municipal solid waste and medical waste incineration plant in Chongqing were (26.4 +/- 22.7) microg x m(-3) and (3.1 +/- 0.8) microg x m(-3) in exhaust gas respectively, (5279.2 +/- 798.0) microg x kg(-1) and (11,709.5 +/- 460.5) microg x kg(-1) in fly ash respectively. Besides, the distribution proportions of the mercury content from municipal solid waste and medical waste in exhaust gas, fly ash, and bottom ash were 34.0%, 65.3%, 0.7% and 32.3%, 67.5%, 0.2% respectively; The mercury removal efficiencies of municipal solid waste and medical waste incineration plants were 66.0% and 67.7% respectively. The atmospheric mercury emission factors of municipal solid waste and medical waste incineration plants were (126.7 +/- 109.0) microg x kg(-1) and (46.5 +/- 12.0) microg x kg(-1) respectively. Compared with domestic municipal solid waste incineration plants in the Pearl River Delta region, the atmospheric mercury emission factor of municipal solid waste incineration plant in Chongqing was lower. PMID:27363131

  17. 40 CFR 266.106 - Standards to control metals emissions.

    Science.gov (United States)

    2010-07-01

    ... height (Ha) may not exceed good engineering practice as specified in 40 CFR 51.100(ii). (iii) If the TESH... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Standards to control metals emissions... Standards to control metals emissions. (a) General. The owner or operator must comply with the...

  18. 40 CFR 52.1384 - Emission control regulations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Emission control regulations. 52.1384 Section 52.1384 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Montana § 52.1384 Emission control regulations. (a) Administrative Rules...

  19. Strategies for controlling pollution from vehicular emissions in Beijing

    International Nuclear Information System (INIS)

    The paper describes the severe situation of vehicular emission in Beijing and discusses the following mitigation strategies: Improving fuel quality, controlling the exhaust from new vehicles, controlling the emissions from vehicles in use through e.g. Inspection Maintenance (I/M), renovating in-use vehicles and scrapping of old vehicles and road infrastructure and traffic policies. (Author)

  20. Atmospheric Ammonia Emissions and a Nitrogen Mass Balance for a Dairy

    Science.gov (United States)

    Rumburg, B. P.; Mount, G. H.; Filipy, J. M.; Lamb, B.; Yonge, D.; Wetherelt, S.

    2003-12-01

    Atmospheric ammonia (NH3) emissions have many impacts on the environment and human health. Environmental NH3 impacts include terrestrial and aquatic eutrophication, soil acidification, and aerosol formation. Aerosols affect global radiative transfer and have been linked to human health effects. The global emissions of NH3 are estimated to be 45 Tg N yr-1 (Dentener and Crutzen, 1994) with most of the emissions coming from domestic animals. The largest per animal emission come from dairy cows at 33 kg N animal{-1} year{-1} versus 10 kg N animal{-1} {-1} for cattle. On a global scale the emissions uncertainty is about 25%, but local emissions are highly uncertain (Bouwman et al., 1997). Local emissions determination is required for proper treatment in air pollution models. The main sources of emission from dairies are the cow stalls where urea and manure react to form NH3, the storage lagoons where NH3 is the end product of microbial degradation and the disposal of the waste. There have been numerous studies of NH3 emissions in Europe but farming practices are quite different in Europe than in the U.S.. The impact of these differences on emissions is unknown. We have been studying the NH3 emissions from the Washington State University dairy for three years to develop a detailed emission model for use in a regional air pollution model. NH3 is measured using a short-path spectroscopic absorption near 200 nm with a sensitivity of a few ppbv and a time resolution of a few seconds. The open air short-path method is advantageous because it is self calibrating and avoids inlet wall adherence which is a major problem for most NH3 measurement techniques. A SF6 tracer technique has been used to measure fluxes from the three main emission sources: the cow stalls, anaerobic lagoon and the waste application to grass fields using a sprinkler system. Estimated yearly emissions from each source will be compared to a nitrogen mass balance model for the dairy.

  1. CarbonTracker-CH4: an assimilation system for estimating emissions of atmospheric methane

    Directory of Open Access Journals (Sweden)

    L. M. Bruhwiler

    2014-01-01

    Full Text Available We describe an assimilation system for atmospheric methane (CH4, CarbonTracker-CH4, and demonstrate the diagnostic value of global or zonally averaged CH4 abundances for evaluating the results. We show that CarbonTracker-CH4 is able to simulate the observed zonal average mole fractions and capture inter-annual variability in emissions quite well at high northern latitudes (53–90° N. CarbonTracker-CH4 estimates of total fluxes at high northern latitudes are about 81 Tg CH4 yr−1, about 12 Tg CH4 yr−1 (13% lower than prior estimates, a result that is consistent with other atmospheric inversions. Emissions from European wetlands are decreased by 30%, a result consistent with previous; however, emissions from wetlands in Boreal Eurasia are increased relative to the prior estimate. Although CarbonTracker-CH4 does not estimate increases in emissions from high northern latitudes for 2000 through 2010, significant inter-annual variability in high northern latitude fluxes is recovered. During the exceptionally warm Arctic summer of 2007, estimated emissions were greater than the decadal average by 4.4 Tg CH4 yr−1. In 2008, temperatures returned to more normal values over Arctic North America while they stayed above normal over Arctic Eurasia. CarbonTracker-CH4 estimates were 2.4 Tg CH4 yr−1 higher than the decadal average, and the anomalous emissions occurred over Arctic Eurasia, suggesting that the data allow discrimination between these two source regions. Also, the emission estimates respond to climate variability without having the system constrained by climate parameters. CarbonTracker-CH4 estimates for temperate latitudes are only slightly increased over prior estimates, but about 10 Tg CH4 yr−1 is redistributed from Asia to North America. We used time invariant prior flux estimates, so for the period from 2000 to 2006, when the growth rate of global atmospheric CH4 was very small, the assimilation does not produce increases in natural

  2. Correcting atmospheric effects in thermal ground observations for hyperspectral emissivity estimation

    Science.gov (United States)

    Timmermans, Joris; Buitrago, Maria

    2014-05-01

    Knowledge of Land surface temperature is of crucial importance in energy balance studies and environmental modeling. Accurate retrieval of land surface temperature (LST) demands detailed knowledge of the land surface emissivity. Measured radiation by remote sensing sensors to land surface temperature can only be performed using a-priori knowledge of the emissivity. Uncertainties in the retrieval of this emissivity can cause huge errors in LST estimations. The retrieval of emissivity (and LST) is per definition an underdetermined inversion, as only one observation is made while two variables are to be estimated. Several researches have therefore been performed on measuring emissivity, such as the normalized emissivity method, the temperature-emissivity separation (TES) using the minimum and maximum difference of emissivity and the use of vegetation indices. In each of these approaches atmospherically corrected radiance measurements by remote sensing sensors are correlated to ground measurements. Usually these ground measurements are performed with the ground equivalent of the remote sensing sensors; the CIMEL 312-2 has the same spectral bands as ASTER. This way parameterizations acquired this way are only usable for specific sensors and need to be redone for newer sensors. Recently hyperspectral thermal radiometers, such as the MIDAC, have been developed that can solve this problem. By using hyperspectral observations of emissivity, together with sensor simulators, ground measurements of different satellite sensor can be simulated. This facilitates the production of validation data for the different TES algorithms. However before such measurements can be performed extra steps of processing need to be performed. Atmospheric correction becomes more important in hyperspectral observations than for broadband observations, as energy levels measured per band is lower. As such the atmosphere has a relative larger contribution if bandwidths become smaller. The goal of this

  3. Annual emissions of mercury to the atmosphere from natural sources in Nevada and California

    Science.gov (United States)

    Coolbaugh, M.F.; Gustin, M.S.; Rytuba, J.J.

    2002-01-01

    The impact of natural source emissions on atmospheric mercury concentrations and the biogeochemical cycle of mercury is not known. To begin to assess this impact, mercury emissions to the atmosphere were scaled up for three areas naturally enriched in mercury: the Steamboat Springs geothermal area, Nevada, the New Idria mercury mining district, California, and the Medicine Lake volcano, California. Data used to scale up area emissions included mercury fluxes, measured in-situ using field flux chambers, from undisturbed and disturbed geologic substrates, and relationships between mercury emissions and geologic rock types, soil mercury concentrations, and surface heat flux. At select locations mercury fluxes were measured for 24 h and the data were used to adjust fluxes measured at different times of the day to give an average daily flux. This adjustment minimized daily temporal variability, which is observed for mercury flux because of light and temperature effects. Area emissions were scaled spatially and temporally with GIS software. Measured fluxes ranged from 0.3 to approximately 50 ng m-2 h-1 at undisturbed sites devoid of mercury mineralization, and to greater than 10,000 ng m-2 h-1 from substrates that were in areas of mercury mining. Area-averaged fluxes calculated for bare soil at Steamboat Springs, New Idria, and Medicine Lake of 181, 9.2, and 2 ng m-2 h-1, respectively, are greater than fluxes previously ascribed to natural non-point sources, indicating that these sources may be more significant contributors of mercury to the atmosphere than previously realized.

  4. Atmospheric ammonia over China: emission estimates and impacts on air quality

    Science.gov (United States)

    Zhang, Lin; Zhao, Yuanhong; Chen, Youfan; Henze, Daven

    2016-04-01

    Ammonia (NH3) in the atmosphere is an important precursor of inorganic aerosols, and its deposition through wet and dry processes can cause adverse effects on ecosystems. The ammonia emissions over China are particularly large due to intensive agricultural activities, yet our current estimates of Chinese ammonia emissions and associated consequences on air quality are subject to large errors. Here we use the GEOS-Chem chemical transport model and its adjoint model to better quantify this issue. The TES satellite observations of ammonia concentrations and surface measurements of wet deposition fluxes are assimilated into the model to constrain the ammonia emissions over China. Optimized emissions show a strong seasonal variability with emissions in summer a factor of 3 higher than winter. We improve the bottom-up estimate of Chinese ammonia emissions from fertilizer use by using more practical feritilizer application rates for different crop types, which explains most of the discrepancies between our top-down estimates and prior emission estimates. We further use the GEOS-Chem adjoint at 0.25x0.3125 degree resolution to examine the sources contributing to the PM2.5 air pollution over North China. We show that wintertime PM2.5 over Beijing is largely contributed by residential and industrial sources, and ammonia emissions from agriculture activities. PM2.5 concentrations over North China are particularly sensitive to NH3 emissions in cold seasons due to strong nitrate formation. By converting shorted-lived nitric acid to aerosol nitrate, NH3 significantly promotes the regional transport influences of PM2.5 sources.

  5. Modeling Atmospheric Emissions and Calculating Mortality Rates Associated with High Volume Hydraulic Fracturing Transportation

    Science.gov (United States)

    Mathews, Alyssa

    Emissions from the combustion of fossil fuels are a growing pollution concern throughout the global community, as they have been linked to numerous health issues. The freight transportation sector is a large source of these emissions and is expected to continue growing as globalization persists. Within the US, the expanding development of the natural gas industry is helping to support many industries and leading to increased transportation. The process of High Volume Hydraulic Fracturing (HVHF) is one of the newer advanced extraction techniques that is increasing natural gas and oil reserves dramatically within the US, however the technique is very resource intensive. HVHF requires large volumes of water and sand per well, which is primarily transported by trucks in rural areas. Trucks are also used to transport waste away from HVHF well sites. This study focused on the emissions generated from the transportation of HVHF materials to remote well sites, dispersion, and subsequent health impacts. The Geospatial Intermodal Freight Transport (GIFT) model was used in this analysis within ArcGIS to identify roadways with high volume traffic and emissions. High traffic road segments were used as emissions sources to determine the atmospheric dispersion of particulate matter using AERMOD, an EPA model that calculates geographic dispersion and concentrations of pollutants. Output from AERMOD was overlaid with census data to determine which communities may be impacted by increased emissions from HVHF transport. The anticipated number of mortalities within the impacted communities was calculated, and mortality rates from these additional emissions were computed to be 1 in 10 million people for a simulated truck fleet meeting stricter 2007 emission standards, representing a best case scenario. Mortality rates due to increased truck emissions from average, in-use vehicles, which represent a mixed age truck fleet, are expected to be higher (1 death per 341,000 people annually).

  6. Radiative Forcing associated with Particulate Carbon Emissions resulting from the Use of Mercury Control Technology

    Science.gov (United States)

    Clack, H.; Penner, J. E.; Lin, G.

    2013-12-01

    Mercury is a persistent, toxic metal that bio-accumulates within the food web and causes neurological damage and fetal defects in humans. The U.S. was the first country to regulate the leading anthropogenic source of mercury into the atmosphere: coal combustion for electric power generation. The U.S. EPA's 2005 Clean Air Mercury Rule (CAMR) was replaced and further tightened in 2012 by the Mercury and Air Toxics Standard (MATS), which required existing coal-fired utilities to reduce their mercury emissions by approximately 90% by 2015. Outside the U.S., the Governing Council of the United Nations Environment Programme (UNEP) has passed the legally binding Minamata global mercury treaty that compels its signatory countries to prevent and reduce the emission and release of mercury. The most mature technology for controlling mercury emissions from coal combustion is the injection into the flue gas of powdered activated carbon (PAC) adsorbents having chemically treated surfaces designed to rapidly oxidize and adsorb mercury. However, such PAC is known to have electrical properties that make it difficult to remove from flue gas via electrostatic precipitation, by far the most common particulate control technology used in countries such as the U.S., India, and China which rely heavily on coal for power generation. As a result, PAC used to control mercury emissions can be emitted into the atmosphere, the sub-micron fraction of which may result in unintended radiative forcing similar to black carbon (BC). Here, we estimate the potential increases in secondary BC emissions, those not produced from combustion but arising instead from the use of injected PAC for mercury emission reduction. We also calculate the radiative forcing associated with these secondary BC emissions by using a global atmospheric chemical transport model coupled with a radiative transfer model.

  7. Emission Fourier transform spectroscopy for the remote sensing of the atmosphere

    Science.gov (United States)

    Bianchini, Giovanni; Cortesi, Ugo; Palchetti, Luca

    2002-02-01

    Fourier transform spectrometers (FTS), thanks to their intrinsic advantages of high throughput, high spectral resolution and multiplex acquisition of spectral channels, offer a powerful tool for the characterisation of the Earth's atmosphere. The use of photon noise limited detectors in FTS instruments operating in the middle/far infrared spectral region permits high sensitivity emission spectroscopy measurements, without the limitations arising from the use of an external radiation source. The wide operating spectral range of FTS instruments makes possible simultaneous detection of different atmospheric chemical species that show rotational and vibrational spectral bands in the middle/far infrared region. Spatially resolved measurements of the concentration of the interesting species are of fundamental interest in the study of local phenomena in atmospheric chemistry and physics, and can be obtained through the use of various observation and data inversion techniques. Among these, the best results in terms of vertical resolution are achieved through the limb sounding observation technique from airborne platform. As an example of possibilities offered by the above considered technique, results obtained from the SAFIRE-A (Spectroscopy of the Atmosphere using Far InfraRed Emission-Airborne) during the Antarctic campaign APE-GAIA (Airborne Polar Experiment-Geophysica Aircraft In Antarctica, Ushuaia, Argentina, September-October, 1999) are presented.

  8. Circular polarization of radio emission from air showers probes atmospheric electric fields in thunderclouds.

    Science.gov (United States)

    Gia Trinh, Thi Ngoc; Scholten, Olaf; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Horandel, Jörg R.; Nelles, Anna; Schellart, Pim; Rachen, Jorg; Rossetto, Laura; Rutjes, Casper; ter Veen, Sander; Thoudam, Satyendra

    2016-04-01

    When a high-energy cosmic-ray particle enters the upper layer of the atmosphere, it generates many secondary high-energy particles and forms a cosmic-ray-induced air shower. In the leading plasma of this shower electric currents are induced that emit electromagnetic radiation. These radio waves can be detected with LOw-Frequency ARray (LOFAR) radio telescope. Events have been collected under fair-weather conditions as well as under atmospheric conditions where thunderstorms occur. For the events under the fair weather conditions the emission process is well understood by present models. For the events measured under the thunderstorm conditions, we observe a large fraction of the circular polarization near the core of the shower which is not shown in the events under the fair-weather conditions. This can be explained by the change of direction of the atmospheric electric fields with altitude. Therefore, measuring the circular polarization of radio emission from cosmic ray extensive air showers during the thunderstorm conditions helps to have a better understanding about the structure of atmospheric electric fields in the thunderclouds.

  9. Atmospheric inverse modeling with known physical bounds: an example from trace gas emissions

    Directory of Open Access Journals (Sweden)

    S. M. Miller

    2013-09-01

    Full Text Available Many inverse problems in the atmospheric sciences involve parameters with known physical constraints. Examples include non-negativity (e.g., emissions of some urban air pollutants or upward limits implied by reaction or solubility constants. However, probabilistic inverse modeling approaches based on Gaussian assumptions cannot incorporate such bounds and thus often produce unrealistic results. The atmospheric literature lacks consensus on the best means to overcome this problem, and existing atmospheric studies rely on a limited number of the possible methods with little examination of the relative merits of each. This paper investigates the applicability of several approaches to bounded inverse problems and is also the first application of Markov chain Monte Carlo (MCMC to estimation of atmospheric trace gas fluxes. The approaches discussed here are broadly applicable. A common method of data transformations is found to unrealistically skew estimates for the examined example application. The method of Lagrange multipliers and two MCMC methods yield more realistic and accurate results. In general, the examined MCMC approaches produce the most realistic result but can require substantial computational time. Lagrange multipliers offer an appealing alternative for large, computationally intensive problems when exact uncertainty bounds are less central to the analysis. A synthetic data inversion of US anthropogenic methane emissions illustrates the strengths and weaknesses of each approach.

  10. Humidity control of particle emissions in aeolian systems

    Science.gov (United States)

    McKenna Neuman, Cheryl; Sanderson, Steven

    2008-06-01

    Humidity is an important control of the wind speed required to entrain particles into an air flow and is well known to vary on a global scale, as do dust emissions. This paper reports on wind tunnel experiments which quantify this control through placing a polymer capacitance sensor immediately at the bed surface. The sensor measured changes in the humidity (RH) of the pore air in real time. RH was varied between 15% and 80% and the critical wind speed determined for the release of particles to the air stream. The results strongly support earlier suggestions that fine particles are most affected in relatively dry atmospheres, particularly those which are tightly packed. An analytical model is proposed to describe this relationship which depends on determination of the matric potential from the Kelvin equation. The total contact area between particle asperities adjoined by pendular rings is represented as a power function of the number of layers of adsorbed water. The value of the exponent appears to be governed by the surface roughness of the particles and their packing arrangement. Parallel developments in colloid interface science and atomic force microscopy, relevant to industrial and pharmaceutical applications, support these conclusions in principle and will likely have an important bearing on future progress in parameterization of the proposed model.

  11. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    Directory of Open Access Journals (Sweden)

    H. Cui

    2015-03-01

    rural and remote sites, attributed partly to weaker atmospheric oxidation and SOC formation compared to summer. Enhanced SOC formation from oxidization and anthropogenic activities like biomass combustion is judged to have crucial effects on severe haze events characterized by high particle concentrations. Several observational studies indicate an increasing trend in ambient OC/EC (but not in OC or EC individually from 2000 to 2010, confirming increased atmospheric oxidation of OC across the country. Combining the results of emission estimation and observations, the improvement over prior emission inventories is indicated by inter-annual comparisons and correlation analysis. It is also indicated, however, that the estimated growth in emissions might be faster than observed growth, and that some sources with high primary OC/EC like burning of biomass are still underestimated. Further studies to determine changing emission factors over time in the residential sector and to compare to other measurements such as satellite observations are thus suggested to improve understanding of the levels and trends of primary carbonaceous aerosol emissions in China.

  12. Urban scale atmospheric inversion of CO2 emissions using a high-density surface tower network over Indianapolis area

    Science.gov (United States)

    Lauvaux, T.; Miles, N. L.; Richardson, S.; Davis, K. J.; Deng, A.; Hardesty, R. M.; Shepson, P. B.; Cambaliza, M. L.; Iraci, L. T.; Hillyard, P. W.; Gurney, K. R.; Karion, A.; Mcgowan, L. E.; Possolo, A.; Razlivanov, I. N.; Sarmiento, D.; Sweeney, C.; Turnbull, J. C.; Whetstone, J. R.

    2013-12-01

    Greenhouse Gas emissions from urban areas represent a significant fraction of the overall release of fossil fuel CO2 from the surface of the globe into the atmosphere. Several ongoing efforts attempt to quantify these emissions over a few major cities across the world (i.e. Indianapolis, Los Angeles, Paris, London, Salt Lake City,...) and demonstrate the concept of atmospheric monitoring of city emissions. The accuracy of the method will highly depend on the inverse modeling framework. The atmospheric transport model and the probabilities assumed in the a priori will be used to extract the information content of surface emissions at very fine scales. But incorrect assumptions in the background emissions and concentrations or systematic errors in the local dynamics can generate artificial trends and seasonal variability in the local emissions. The construction of unbiased atmospheric modeling systems and well-defined prior errors remains a critical step in atmospheric emissions monitoring over urban areas. We present here the first inverse emission estimates over Indianapolis using a high-density surface tower network of CO2 analyzers. In order to minimize transport model errors, we developed a WRF-Chem-FDDA modeling system ingesting surface and profile measurements of horizontal mean wind, temperature and moisture in addition to the original CO2 emissions and boundary conditions. The systematic improvement of the simulated atmospheric conditions thanks to the nudging system is critical to identify and retrieve source locations at high resolution over the area. We then present an ensemble of inverse fluxes generated from varying the configuration of the inverse system in order to more accurately represent the probability space, exploring the assumptions in the a priori (i.e. the prior local urban emissions and the background atmospheric concentrations). We finally discuss the detection of trends or changes in the spatial distribution of sources at decadal time

  13. Oxygen emission line properties from analysis of MAVEN-IUVS Echellograms of the Martian atmosphere

    Science.gov (United States)

    Mayyasi, Majd A.; Clarke, John T.; Stewart, Ian; McClintock, William; Schneider, Nicholas M.; Jakosky, Bruce; IUVS Team

    2016-10-01

    The high resolution echelle mode of the Mars Atmosphere and Volatile Evolution (MAVEN) mission Imaging Ultraviolet Spectrograph (IUVS) instrument has been used to spectrally image the sunlit limb of Mars during the spacecraft periapse orbital segments. When multiple images are co-added over a few hours, there are detectable spectral emission features that have been identified to originate from atomic and molecular neutral species such as H, D, N, O, CO as well as from C+ ions. The echelle detector has a localized spectral resolution of ~0.008 Angstrom and is therefore capable of spectrally resolving the oxygen resonant triplet (130.217, 130.486 and 130.603 nm) and forbidden doublet (135.560 and 135.851 nm) emission lines. The brightness of each of these emission lines has been determined and will be compared with detected brightnesses of other species. The emission line integrated brightness ratios are being analyzed for insights into the abundance, excitation, and variability of oxygen in the martian atmosphere.

  14. The Reanalysis of the ROSAT Data of GQ Mus (1983) Using White Dwarf Atmosphere Emission Models

    CERN Document Server

    Balman, S

    2001-01-01

    The analyses of X-ray emission from classical novae during the outburst stage have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple blackbody model of emission. Thus, $ROSAT$ Position Sensitive Proportional Counter (PSPC) archival data of the classical novae GQ Mus 1983 (GQ Mus) have been reanalyzed in order to understand the spectral development in the X-ray wavelengths during the outburst stage. The X-ray spectra are fitted with the hot white dwarf atmosphere emission models developed for the remnants of classical novae near the Eddington luminosity. The post-outburst X-ray spectra of the remnant white dwarf is examined in the context of evolution on the Hertzsprung-Russell diagram using C-O enhanced atmosphere models. The data obtained in 1991 August (during the ROSAT All Sky Survey) indicate that the effective temperature is kT_e<54 eV (<6.2x10^5 K). The 1992 February data show that the white dwarf ...

  15. Methane emission by termites: Impacts on the self-cleansing mechanisms of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Mugedo, J.Z.A. [Maseno Univ. College (Kenya)

    1996-12-31

    Termites are reported to emit large quantities of methane, carbon dioxide, carbon monoxide, hydrogen and dimethyl sulfide. The emission of other trace gases, namely C{sub 2} to C{sub 10} hydrocarbons, is also documented. We have carried out, both in the field and in the laboratory, measurements of methane emissions by Macrotermes subhyalinus (Macrotermitinae), Trinervitermes bettonianus (Termitinae), and unidentified Cubitermes and Microcerotermes species. Measured CH{sub 4} field flux rates ranged from 3.66 to 98.25g per m{sup 2} of termite mound per year. Laboratory measurements gave emission rates that ranged from 14.61 to 165.05 mg CH{sub 4} per termite per year. Gaseous production in all species sampled varied both within species and from species to species. Recalculated global emission of methane from termites was found to be 14.0 x 10{sup 12} g CH{sub 4}, per year. From our study, termites contribution to atmospheric methane content is between 1.11% and 4.25% per year. This study discusses the greenhouse effects as well as photochemical disposal of methane in the lower atmosphere in the tropics and the impacts on the chemistry of HO{sub x} systems and CL{sub x} cycles.

  16. HST/ACS Observations of Europa's Atmospheric UV Emission at Eastern Elongation

    CERN Document Server

    Saur, Joachim; Roth, Lorenz; Nimmo, Francis; Strobel, Darrell F; Retherford, Kurt D; McGrath, Melissa A; Schilling, Nico; Gérard, Jean-Claude; Grodent, Denis

    2011-01-01

    We report results of a Hubble Space Telescope (HST) campaign with the Advanced Camera for Surveys to observe Europa at eastern elongation, i.e. Europa's leading side, on 2008 June 29. With five consecutive HST orbits, we constrain Europa's atmospheric \\ion{O}{1} 1304 \\A and \\ion{O}{1} 1356 \\A emissions using the prism PR130L. The total emissions of both oxygen multiplets range between 132 $\\pm$ 14 and 226 $\\pm$ 14 Rayleigh. An additional systematic error with values on the same order as the statistical errors may be due to uncertainties in modelling the reflected light from Europa's surface. The total emission also shows a clear dependence of Europa's position with respect to Jupiter's magnetospheric plasma sheet. We derive a lower limit for the O$_2$ column density of 6 $\\times$ 10$^{18}$ m$^{-2}$. Previous observations of Europa's atmosphere with STIS in 1999 of Europa's trailing side show an enigmatic surplus of radiation on the anti-Jovian side within the disk of Europa. With emission from a radially symm...

  17. Observation of the Emission Spectra of an Atmospheric Pressure Radio-frequency Plasma Jet

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An atmospheric pressure plasma jet (APPJ) using radio-frequency (13.56 MHz)power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species (atomic helium, atomic oxygen and metastable oxygen) generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2(b1∑g+) are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity (777.4 nm) between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.

  18. Atmospheric inversion for cost effective quantification of city CO2 emissions

    Science.gov (United States)

    Wu, L.; Broquet, G.; Ciais, P.; Bellassen, V.; Vogel, F.; Chevallier, F.; Xueref-Remy, I.; Wang, Y.

    2015-11-01

    Cities, currently covering only a very small portion (market- or policy-based mitigation actions. Here we propose a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. We examine the cost-effectiveness and the performance of such a tool. The instruments presently used to measure CO2 concentrations at research stations are expensive. However, cheaper sensors are currently developed and should be useable for the monitoring of CO2 emissions from a megacity in the near-term. Our assessment of the inversion method is thus based on the use of several types of hypothetical networks, with a range of numbers of sensors sampling at 25 m a.g.l. The study case for this assessment is the monitoring of the emissions of the Paris metropolitan area (~ 12 million inhabitants and 11.4 Tg C emitted in 2010) during the month of January 2011. The performance of the inversion is evaluated in terms of uncertainties in the estimates of total and sectoral CO2 emissions. These uncertainties are compared to a notional ambitious target to diagnose annual total city emissions with an uncertainty of 5 % (2-sigma). We find that, with 10 stations only, which is the typical size of current pilot networks that are deployed in some cities, the uncertainty for the 1-month total city CO2 emissions is significantly reduced by the inversion by ~ 42 % but still corresponds to an annual uncertainty that is two times larger than the target of 5 %. By extending the network from 10 to 70 stations, the inversion can meet this requirement. As for major sectoral CO2 emissions, the uncertainties in the inverted emissions using 70 stations are reduced significantly over that obtained using 10 stations by 32 % for commercial and residential buildings, by 33 % for

  19. Inverse modelling of national and European CH4 emissions using the atmospheric zoom model TM5

    Directory of Open Access Journals (Sweden)

    P. Bergamaschi

    2005-01-01

    Full Text Available A synthesis inversion based on the atmospheric zoom model TM5 is used to derive top-down estimates of CH4 emissions from individual European countries for the year 2001. We employ a model zoom over Europe with 1° × 1° resolution that is two-way nested into the global model domain (with resolution of 6° × 4°. This approach ensures consistent boundary conditions for the zoom domain and thus European top-down estimates consistent with global CH4 observations. The TM5 model, driven by ECMWF analyses, simulates synoptic scale events at most European and global sites fairly well, and the use of high-frequency observations allows exploiting the information content of individual synoptic events. A detailed source attribution is presented for a comprehensive set of 56 monitoring sites, assigning the atmospheric signal to the emissions of individual European countries and larger global regions. The available observational data put significant constraints on emissions from different regions. Within Europe, in particular several Western European countries are well constrained. The inversion results suggest up to 50-90% higher anthropogenic CH4 emissions in 2001 for Germany, France and UK compared to reported UNFCCC values (EEA, 2003. A recent revision of the German inventory, however, resulted in an increase of reported CH4 emissions by 68.5% (EEA, 2004, being now in very good agreement with our top-down estimate. The top-down estimate for Finland is distinctly smaller than the a priori estimate, suggesting much smaller CH4 emissions from Finnish wetlands than derived from the bottom-up inventory. The EU-15 totals are relatively close to UNFCCC values (within 4-30% and appear very robust for different inversion scenarios.

  20. Reducing Uncertainty in Life Cycle CH4 Emissions from Natural Gas using Atmospheric Inversions

    Science.gov (United States)

    Schwietzke, S.; Griffin, W.; Matthews, S.

    2012-12-01

    Methane emissions associated with the production and use of natural gas (NG) are highly uncertain because of challenges to accurately measure fugitive CH4 emissions from NG leaks and venting throughout a large and complex industry. Better understanding the CH4 emissions from the NG life cycle is important for two reasons. First, the rising interest in NG use associated with the recent development of unconventional sources, such as shale gas, may cause a shift in the future energy system from coal towards more NG. Given its relatively high greenhouse gas potency, fugitive CH4 emissions from the NG life cycle have the potential to outweigh lower CO2 emissions compared to coal use in terms of their climate impacts over the next few decades. Second, worldwide NG related CH4 emissions play a key role in understanding the global CH4 budget. According to current atmospheric inversion studies, NG and oil production account for about 12% of global CH4 emissions. However, these results largely depend on prior emissions estimates whose uncertainties are poorly documented. The objective of this research is to analyze which ranges of global fugitive CH4 emissions from the NG life cycle are reasonable given atmospheric observations as a constraint. We establish a prior global CH4 inventory for NG, oil, and coal using emissions data from the life cycle assessment (LCA) literature. This inventory includes uncertainty estimates for different fuels, world regions, and time periods based on LCA literature, which existing inventories do not account for. Furthermore, global CH4 inversion modeling will be used to test bottom-up hypotheses of high NG leakage and venting associated with the upper bound of the prior inventory. Given the use of detailed LCA emissions factors, we will test bottom-up scenarios regarding management and technology improvements over time. The emissions inventory will be established for the past decade, and inversion modeling will be carried out using NOAA

  1. Nitric oxide and nitrous oxide emission from Hungarian forest soils; link with atmospheric N-deposition

    Directory of Open Access Journals (Sweden)

    L. Horváth

    2005-06-01

    Full Text Available Studies of forest nitrogen (N budgets generally measure inputs to the atmosphere in wet and dry precipitation and outputs via hydrologic export. Although denitrification has been shown to be important in many wetland ecosystems, emission of nitrogen oxides from forest soils is an important, and often overlooked, component of an ecosystem nitrogen budget. During one year (2002-2003, emissions of nitric oxide (NO and nitrous oxide (N2O were measured from Sessile oak and Norway spruce forest soils in northeast Hungary. Accumulation in small static chambers followed by gas chromatography-mass spectrometry detection was used for the estimation of N2O emission flux. Because there are rapid chemical reactions of NO and ozone, small dynamic chambers were used for in situ NO flux measurements. Average soil emissions of NO were 1.2 and 2.1 µgNm-2h-1, and for N2O were 15 and 20 µgNm-2h-1, for spruce and oak soils, respectively. The previously determined nitrogen balance between the atmosphere and the forest ecosystem was re-calculated using these soil emission figures. The total (dry + wet atmospheric N-deposition to the soil was 1.42 and 1.59gNm-2yr-1 for spruce and oak, respectively, while the soil emissions are 0.14 and 0.20 gNm-2yr-1. Thus, about 10-13% of N compounds deposited to the soil, mostly as NH3/NH4+ and HNO3/NO3-, are transformed in the soil and emitted back to the atmosphere, mostly as a greenhouse gas (N2O.

  2. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980-2007

    Science.gov (United States)

    Tian, H. Z.; Wang, Y.; Xue, Z. G.; Cheng, K.; Qu, Y. P.; Chai, F. H.; Hao, J. M.

    2010-12-01

    Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg), arsenic (As), and selenium (Se) from coal combustion in China for the period 1980-2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the equipped air pollution control devices configuration (Dust collectors, FGD, etc.). Specifically, multi-year emission inventories of Hg, As, and Se from 30 provinces and 4 economic sectors (thermal power, industry, residential use, and others) are evaluated and analyzed in detail. Furthermore, the gridded distribution of provincial-based Hg, As, and Se emissions in 2005 at a resolution of 1° × 1° is also plotted. It shows that the calculated national total atmospheric emissions of Hg, As, and Se from coal combustion have rapidly increased from 73.59 t, 635.57 t, and 639.69 t in 1980 to 305.95 t, 2205.50 t, and 2352.97 t in 2007, at an annually averaged growth rate of 5.4%, 4.7%, and 4.9%, respectively. The industrial sector is the largest source for Hg, As, and Se, accounting for about 50.8%, 61.2%, and 56.2% of the national totals, respectively. The share of power plants is 43.3% for mercury, 24.9% for arsenic, and 33.4% for selenium, respectively. Also, it shows remarkably different regional contribution characteristics of these 3 types of trace elements, the top 5 provinces with the heaviest mercury emissions in 2007 are Shandong (34.40 t), Henan (33.63 t), Shanxi (21.14 t), Guizhou (19.48 t), and Hebei (19.35 t); the top 5 provinces with the heaviest arsenic emissions in 2007 are Shandong (219.24 t), Hunan (213.20 t), Jilin (141.21 t), Hebei (138.54 t), and Inner Mongolia (127.49 t); while the top 5 provinces with the heaviest selenium emissions in 2007 are Shandong (289

  3. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980–2007

    Directory of Open Access Journals (Sweden)

    H. Z. Tian

    2010-09-01

    Full Text Available Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg, arsenic (As, and selenium (Se from coal combustion in China for the period 1980–2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the equipped air pollution control devices configuration (Dust collectors, FGD, etc.. Specifically, multi-year emission inventories of Hg, As, and Se from 30 provinces and 4 economic sectors (thermal power, industry, residential use, and others are evaluated and analyzed in detail. Furthermore, the gridded distribution of provincial-based Hg, As, and Se emissions in 2005 at a resolution of 1°×1° is also plotted. It shows that the calculated national total atmospheric emissions of Hg, As, and Se from coal combustion have rapidly increased from 73.59 t, 635.57 t, and 639.69 t in 1980 to 305.95 t, 2205.50 t, and 2352.97 t in 2007, at an annually averaged growth rate of 5.4%, 4.7%, and 4.9%, respectively. The industrial sector is the largest source for Hg, As, and Se, accounting for about 50.8%, 61.2%, and 56.2% of the national totals, respectively. The share of power plants is 43.3% for mercury, 24.9% for arsenic, and 33.4% for selenium, respectively. Also, it shows remarkably different regional contribution characteristics of these 3 types of trace elements, the top 5 provinces with the heaviest mercury emissions in 2007 are Shandong (34.40 t, Henan (33.63 t, Shanxi (21.14 t, Guizhou (19.48 t, and Hebei (19.35 t; the top 5 provinces with the heaviest arsenic emissions in 2007 are Shandong (219.24 t, Hunan (213.20 t, Jilin (141.21 t, Hebei (138.54 t, and Inner Mongolia (127.49 t; while the top 5 provinces with the heaviest selenium emissions in 2007 are Shandong

  4. On the effect of emissions from aircraft engines on the state of the atmosphere

    Directory of Open Access Journals (Sweden)

    U. Schumann

    Full Text Available Emissions from aircraft engines include carbon dioxide, water vapour, nitrogen oxides, sulphur components and various other gases and particles. Such emissions from high-flying global civil subsonic air traffic may cause anthropogenic climate changes by an increase of ozone and cloudiness in the upper troposphere, and by an enhanced greenhouse effect. The absolute emissions by air traffic are small (a few percent of the total compared to surface emissions. However, the greenhouse effect of emitted water and of nitrogen oxides at cruise altitude is potentially large compared to that of the same emissions near the earth's surface because of relatively large residence times at flight altitudes, low background concentrations, low temperature, and large radiative efficiency. Model computations indicate that emission of nitrogen oxides has doubled the background concentration in the upper troposphere between 40°N and 60°N. Models also indicate that this causes an increase of ozone by about 5-20%. Regionally, the observed annual mean change in cloudiness is 0.4%. It is estimated that the resultant greenhouse effect of changes in ozone and thin cirrus cloud cover causes a climatic surface temperature change of 0.01-0.1 K. These temperature changes are small compared to the natural variability. Recent research indicates that the emissions at cruise altitude may increase the amount of stratospheric aerosols and polar stratospheric clouds and thereby have an impact on the atmospheric environment. Air traffic is increasing about 5-6% per year, fuel consumption by about 3%, hence the effects of the related emissions are expected to grow. This paper surveys the state of knowledge and describes several results from recent and ongoing research.

  5. Ammonia emissions from an anaerobic digestion plant estimated using atmospheric measurements and dispersion modelling.

    Science.gov (United States)

    Bell, Michael W; Tang, Y Sim; Dragosits, Ulrike; Flechard, Chris R; Ward, Paul; Braban, Christine F

    2016-10-01

    Anaerobic digestion (AD) is becoming increasingly implemented within organic waste treatment operations. The storage and processing of large volumes of organic wastes through AD has been identified as a significant source of ammonia (NH3) emissions, however the totality of ammonia emissions from an AD plant have not been previously quantified. The emissions from an AD plant processing food waste were estimated through integrating ambient NH3 concentration measurements, atmospheric dispersion modelling, and comparison with published emission factors (EFs). Two dispersion models (ADMS and a backwards Lagrangian stochastic (bLS) model) were applied to calculate emission estimates. The bLS model (WindTrax) was used to back-calculate a total (top-down) emission rate for the AD plant from a point of continuous NH3 measurement downwind from the plant. The back-calculated emission rates were then input to the ADMS forward dispersion model to make predictions of air NH3 concentrations around the site, and evaluated against weekly passive sampler NH3 measurements. As an alternative approach emission rates from individual sources within the plant were initially estimated by applying literature EFs to the available site parameters concerning the chemical composition of waste materials, room air concentrations, ventilation rates, etc. The individual emission rates were input to ADMS and later tuned by fitting the simulated ambient concentrations to the observed (passive sampler) concentration field, which gave an excellent match to measurements after an iterative process. The total emission from the AD plant thus estimated by a bottom-up approach was 16.8±1.8mgs(-1), which was significantly higher than the back-calculated top-down estimate (7.4±0.78mgs(-1)). The bottom-up approach offered a more realistic treatment of the source distribution within the plant area, while the complexity of the site was not ideally suited to the bLS method, thus the bottom-up method is believed

  6. Design of viewing windows for controlled-atmosphere chambers

    International Nuclear Information System (INIS)

    A guide to the design of safe viewing windows is presented. Design criteria, the properties of materials, the problems of structural design in unreliable materials such as glass, the mathematics of reliability and redundance, and problems associated with testing windows are discussed, and formulas are presented for the design of windows. Criteria adopted at ORNL for controlled-atmosphere chambers are presented, a program for surveying and upgrading the safety of existing facilities is described, and the results of this program are reported

  7. Top-down constraints on atmospheric mercury emissions and implications for global biogeochemical cycling

    Directory of Open Access Journals (Sweden)

    S. Song

    2015-02-01

    Full Text Available We perform global-scale inverse modeling to constrain present-day atmospheric mercury emissions and relevant physio-chemical parameters in the GEOS-Chem chemical transport model. We use Bayesian inversion methods combining simulations with GEOS-Chem and ground-based Hg0 observations from regional monitoring networks and individual sites in recent years. Using optimized emissions/parameters, GEOS-Chem better reproduces these ground-based observations, and also matches regional over-water Hg0 and wet deposition measurements. The optimized global mercury emission to the atmosphere is ~5.8 Gg yr−1. The ocean accounts for 3.2 Gg yr−1 (55% of the total, and the terrestrial ecosystem is neither a net source nor a net sink of Hg0. The optimized Asian anthropogenic emission of Hg0 (gas elemental mercury is 650–1770 Mg yr−1, higher than its bottom-up estimates (550–800 Mg yr−1. The ocean parameter inversions suggest that dark oxidation of aqueous elemental mercury is faster, and less mercury is removed from the mixed layer through particle sinking, when compared with current simulations. Parameter changes affect the simulated global ocean mercury budget, particularly mass exchange between the mixed layer and subsurface waters. Based on our inversion results, we re-evaluate the long-term global biogeochemical cycle of mercury, and show that legacy mercury becomes more likely to reside in the terrestrial ecosystem than in the ocean. We estimate that primary anthropogenic mercury contributes up to 23% of present-day atmospheric deposition.

  8. NO emission characteristics of superfine pulverized coal combustion in the O2/CO2 atmosphere

    International Nuclear Information System (INIS)

    Highlights: • Superfine pulverized coal combustion in O2/CO2 atmosphere is a new promising technology. • NO emissions of superfine pulverized coal combustion in O2/CO2 mixture were focused. • Coal particle sizes have significant effects on NO emissions in O2/CO2 combustion. - Abstract: The combination of O2/CO2 combustion and superfine pulverized coal combustion technology can make full use of their respective merits, and solve certain inherent disadvantages of each technology. The technology of superfine pulverized coal combustion in the O2/CO2 atmosphere is easy and feasible to be retrofitted with few reconstructions on the existing devices. It will become a useful and promising method in the future. In this paper, a one-dimensional drop-tube furnace system was adopted to study the NO emission characteristics of superfine pulverized coal combustion in the O2/CO2 atmosphere. The effects of coal particle size, coal quality, furnace temperature, stoichiometric ratio, etc. were analyzed. It is important to note that coal particle sizes have significant influence on NO emissions in the O2/CO2 combustion. For the homogeneous NO reduction, smaller coal particles can inhibit the homogeneous NO formations under fuel-rich combustion conditions, while it becomes disadvantageous for fuel-lean combustion. However, under any conditions, heterogeneous reduction is always more significant for smaller coal particle sizes, which have smoother pore surfaces and simpler pore structures. The results from this fundamental research will provide technical support for better understanding and developing this new combustion process

  9. A Result On Implicit Consensus with Application to Emissions Control

    OpenAIRE

    Knorn, Florian; Corless, Martin J.; Shorten, Robert N.

    2011-01-01

    This paper is concerned with a class of decentralised control problems that arise in contemporary applications where agents cooperate to control and regulate a global quantity, are limited in the manner in which they communicate with each other, and are required to reach consensus on some implicit variable (for instance, CO2 emissions). An algorithm is presented for achieving this goal. A simplified application of the algorithm to emissions control for a fleet of Plug-in ...

  10. Atmospheric Impact of Large Methane Emissions and the Gulf Oil Spill

    Science.gov (United States)

    Bhattacharyya, S.; Cameron-Smith, P. J.; Bergmann, D. J.

    2010-12-01

    A vast quantity of a highly potent greenhouse gas, methane, is locked in the solid phase as methane clathrates in ocean sediments and underneath permafrost regions. Clathrates are ice-like deposits containing a mixture of water and gas (mostly methane) which are stable under high pressure and low temperatures. Current estimates are about 1600 - 2000 GtC present in oceans and about 400GtC in Arctic permafrost (Archer et al. 2009). This is about 4000 times that of current annual emissions. In a warming climate, increase in ocean temperatures could rapidly destabilize the geothermal gradient which in turn could lead to dissociation of the clathrates and release of methane into the ocean and subsequently into the atmosphere as well. This could result in a number of effects including strong greenhouse heating, increased surface ozone, reduced stratospheric ozone, and intensification of the Arctic ozone hole. Many of the effects in the chemistry of the atmosphere are non-linear. In this paper, we present a parametric study of the effect of large scale methane release to the atmosphere. To that end we use the CESM (Community Earth System Model) version 1 with fully active coupled atmosphere-ocean-land model together with super-fast atmospheric chemistry module to simulate the response to increasing CH4 by 2, 3, 10 and 100 times that of the present day. We have also conducted a parametric study of the possible impact of gaseous emissions from the oil spill in the Gulf of Mexico, which is a proxy for future clathrate releases. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. Sulfur oxide adsorbents and emissions control

    Science.gov (United States)

    Li, Liyu; King, David L.

    2006-12-26

    High capacity sulfur oxide absorbents utilizing manganese-based octahedral molecular sieve (Mn--OMS) materials are disclosed. An emissions reduction system for a combustion exhaust includes a scrubber 24 containing these high capacity sulfur oxide absorbents located upstream from a NOX filter 26 or particulate trap.

  12. Emission Control Cost-Effectiveness of Alternative-Fuel Vehicles

    OpenAIRE

    Wang, Quanlu; Sperling, Daniel; Olmstead, Janis

    1993-01-01

    Although various legislation and regulations have been adopted to promote the use of alternative-fuel vehicles for curbing urban air pollution problems, there is a lack of systematic comparisons of emission control cost-effectiveness among various alternative-fuel vehicle types. In this paper, life-cycle emission reductions and life-cycle costs were estimated for passenger cars fueled with methanol, ethanol, liquified petroleum gas, compressed natural gas, and electricity. Vehicle emission es...

  13. Options and Costs of Controlling Ammonia Emissions in Europe

    OpenAIRE

    Klaassen, G.

    1994-01-01

    Ammonia emissions contribute to acidification in Europe. The major emission sources are livestock and fertilizer use. This study presents the costs of controlling ammonia emissions in 33 regions in Europe. Abatement options include low nitrogen feed, stable adaptations, covering manure storage, cleaning stable air, and low ammonia applications of manure. Cost estimates are based on country- and technology-specific data. The structure of livestock population and fertilizer use mean that th...

  14. A sparse reconstruction method for the estimation of multi-resolution emission fields via atmospheric inversion

    Science.gov (United States)

    Ray, J.; Lee, J.; Yadav, V.; Lefantzi, S.; Michalak, A. M.; van Bloemen Waanders, B.

    2015-04-01

    Atmospheric inversions are frequently used to estimate fluxes of atmospheric greenhouse gases (e.g., biospheric CO2 flux fields) at Earth's surface. These inversions typically assume that flux departures from a prior model are spatially smoothly varying, which are then modeled using a multi-variate Gaussian. When the field being estimated is spatially rough, multi-variate Gaussian models are difficult to construct and a wavelet-based field model may be more suitable. Unfortunately, such models are very high dimensional and are most conveniently used when the estimation method can simultaneously perform data-driven model simplification (removal of model parameters that cannot be reliably estimated) and fitting. Such sparse reconstruction methods are typically not used in atmospheric inversions. In this work, we devise a sparse reconstruction method, and illustrate it in an idealized atmospheric inversion problem for the estimation of fossil fuel CO2 (ffCO2) emissions in the lower 48 states of the USA. Our new method is based on stagewise orthogonal matching pursuit (StOMP), a method used to reconstruct compressively sensed images. Our adaptations bestow three properties to the sparse reconstruction procedure which are useful in atmospheric inversions. We have modified StOMP to incorporate prior information on the emission field being estimated and to enforce non-negativity on the estimated field. Finally, though based on wavelets, our method allows for the estimation of fields in non-rectangular geometries, e.g., emission fields inside geographical and political boundaries. Our idealized inversions use a recently developed multi-resolution (i.e., wavelet-based) random field model developed for ffCO2 emissions and synthetic observations of ffCO2 concentrations from a limited set of measurement sites. We find that our method for limiting the estimated field within an irregularly shaped region is about a factor of 10 faster than conventional approaches. It also reduces

  15. Atmospheric dispersion modeling of hazardous air pollutant emissions from USDOE Oak Ridge Reservation Facilities. Volume 1, Independent Assessment conducted from April 1994 to December 1994

    International Nuclear Information System (INIS)

    Title 3 of the 1990 Clean Air Act (CAA) Amendments addresses the emissions of 189 hazardous air pollutants (HAPs) and mandates that EPA develop technology-based [Maximum Achievable Control Technology (MACT)] standards for the control of these pollutants from approximately 174 source categories. After implementation of technology-based standards, EPA is required to further evaluate ''residual risk'' from HAP emissions, and, if required, develop more stringent standards to protect human health and the environment with an ''adequate margin of safety''. Recognizing that EPA will be issuing risk-based regulations after MACT standards have been implemented, the US Department of Energy (DOE), Oak Ridge Operations Office (ORO) has conducted an evaluation of ambient air impacts of HAP emissions from its installations located on the Oak Ridge Reservation (ORR) near Oak Ridge, Tennessee. This report provides results of atmospheric dispersion modeling conducted to determine ambient air impacts of HAP emissions from facilities located on the ORR

  16. Multimode attitude and orbit control for the Atmosphere Explorer spacecraft

    Science.gov (United States)

    Stewart, B.

    1975-01-01

    The orbit profile for the Atmosphere Explorer requires a velocity adjust capability of 2000 ft/sec/sec and individual maneuvers of up to 24 ft/sec in magnitude. This requirement is met by a monopropellant hydrazine propulsion subsystem which also provides, by virtue of the tank arrangement, a means of adjusting the spacecraft center of mass in orbit, thereby minimizing external disturbance torques. The attitude control subsystem is of the momentum bias type. A large internal flywheel furnishes gyroscopic stiffness and permits rapid changes in operating mode (despun to spinning mode) by controlled interchange of momentum between the flywheel and the spacecraft main body.

  17. Volcanoes as emission sources of atmospheric mercury in the Mediterranean basin

    Science.gov (United States)

    Ferrara; Mazzolai; Lanzillotta; Nucaro; Pirrone

    2000-10-01

    Emissions from volcanoes, fumaroles and solfataras as well as contributions from widespread geological anomalies could represent an important source of mercury released to the atmosphere in the Mediterranean basin. Volcanoes located in this area (Etna, Stromboli and Vulcano) are the most active in Europe; therefore, it is extremely important to know their mercury contributions to the regional atmospheric budget. Two main methods are used for the evaluation of volcanic mercury flux: a direct determination of the flux (by measuring in the plume) and an indirect one derived from the determination of the Hg/SO2 (or Hg/S) ratio value, as SO2 emissions are constantly monitored by volcanologists. An attempt to estimate mercury flux from the Vulcano volcano and to establish the Hg/S ratio value has been made along three field campaigns carried out in October 1998, in February and May 1999 sampling several fumaroles. Traditional sampling methods were used to collect both total Hg and S. The average Hg/S ratio value resulted to be 1.2 x 10(-7). From the Hg/S value we derived the Hg/SO2 value, and by assuming that all the volcanoes located in this area have the same Hg/SO2 ratio, mercury emissions from Vulcano and Stromboli were estimated to be in the range 1.3-5.5 kg/year and 7.3-76.6 kg/year respectively, while for Etna mercury flux ranged from 61.8 to 536.5 kg/year. Data reported in literature appear to be overestimated (Fitzgerald WF. Mercury emission from volcanos. In: 4th International conference on mercury as a global pollutant, August 4-8 1996, Hamburg, Germany), volcanic mercury emission does not constitute the main natural source of the metal.

  18. Effects of hydrogen addition to methane on the flame structure and CO emissions in atmospheric burners

    Energy Technology Data Exchange (ETDEWEB)

    Burbano, Hugo J.; Amell, Andres A.; Garcia, Jorge M. [Science and Technology of Gases and Rational Use of Energy Group, Faculty of Engineering, University of Antioquia, Calle 67 No 53-108 Bloque 20-435, Medellin (Colombia)

    2008-07-15

    Hydrogen addition to methane will have an important role to reach a fully developed hydrogen economy. The effects of this addition on the flame structure and CO emissions were evaluated in two different atmospheric burners. Four fuels with the following composition were used: 100%CH{sub 4}, 2%H{sub 2}+98%CH{sub 4}, 6%H{sub 2}+94%CH{sub 4} and 15%H{sub 2}+85%CH{sub 4}. In a single-port atmospheric burner, a decreasing trend in the height of the blue cone with hydrogen addition was determined. The increase in the laminar burning velocity was identified as the main effect on the behavior of this parameter. In a drilled-port atmospheric burner, a significant reduction in CO emissions with hydrogen addition was achieved under two operating conditions: (1) keeping the primary air ratio constant and (2) keeping the primary air ratio and the thermal input constant. The results obtained were consistent with previous experimental studies. This reduction is attributed to a higher concentration of OH radicals as a result of hydrogen addition. (author)

  19. Atmospheric oxygen concentration controls the size history of foraminifers

    Science.gov (United States)

    Payne, J.; Jost, A. B.; Ouyang, X.; Skotheim, J. M.; Wang, S. C.

    2010-12-01

    Body size correlates with numerous physiological traits and thus influences organism fitness. However, long-term controls on size evolution remain poorly understood because few datasets spans sufficiently long intervals. One proposed controlling factor is variation in atmospheric oxygen, which is widely argued to have influenced size evolution in numerous taxa, notably gigantism in arthropods during the late Paleozoic. In this study, we compiled a comprehensive genus- and species-level size database of foraminifers (marine protists) to enable an extensive analysis of factors influencing size evolution. Foraminifers are an ideal study group because they are present in all Phanerozoic periods and have been diverse and abundant in shallow-marine habitats since Devonian time. We observe significant correlation between foraminiferan size and atmospheric oxygen concentration in foraminifers as a whole and in half of the major subclades. Larger size is associated with higher oxygen concentrations, as predicted by simple physiological models based on changes in the ratio of surface area to volume. Because the oxygen content ocean waters is controlled in part by atmospheric pO2, we interpret the association between foraminiferan size and pO2 to result from a direct physiological effect of oxygen availability. Atmospheric oxygen concentration predicts foraminiferan size better than six other Phanerozoic time series (pCO2, sea level, number of named geological formations, δ18O, δ13C, 87Sr/86Sr), further suggesting the correlation between oxygen and size does not occur simply through some common geological cause that influences many aspects of Earth system history. These findings support the hypothesis that widespread Permo-Carboniferous gigantism was enabled by high pO2 and suggest that oxygen availability has been among the most important influences on size evolution through Phanerozoic time.

  20. Atmospheric Emissions and Depositions of Cadmium, Lead, and Zinc in Europe During the Period 1955-1987

    OpenAIRE

    Olendrzynski, K.; Anderberg, S.; Bartnicki, J.; PACYNA J.; Stigliani, W.M.

    1995-01-01

    This paper presents a preliminary estimate of atmospheric emissions of cadmium, lead and zinc in Europe during the period 1955-1987. The emission data are used as input to the IIASA's atmospheric transport model, TRACE m a c e toxic Air concentrations in Europe), to compute cumulative deposition loads of heavy metals onto European soils during the investigated time period. To the authors' knowledge, this is the first attempt of this kind in the open literature. The computed with the TRACE mod...

  1. Energy, Carbon-emission and Financial Savings from Thermostat Control

    Energy Technology Data Exchange (ETDEWEB)

    Blasing, T J [ORNL; Schroeder, Dana [University of Georgia, Athens, GA

    2013-08-01

    Among the easiest approaches to energy, and cost, savings for most people is the adjustment of thermostats to save energy. Here we estimate savings of energy, carbon, and money in the United States of America (USA) that would result from adjusting thermostats in residential and commercial buildings by about half a degree Celsius downward during the heating season and upward during the cooling season. To obtain as small a unit as possible, and therefore the least likely to be noticeable by most people, we selected an adjustment of one degree Fahrenheit (0.56 degree Celsius) which is the gradation used almost exclusively on thermostats in the USA and is the smallest unit of temperature that has been used historically. Heating and/or cooling of interior building space for personal comfort is sometimes referred to as space conditioning, a term we will use for convenience throughout this work without consideration of humidity. Thermostat adjustment, as we use the term here, applies to thermostats that control the indoor temperature, and not to other thermostats such as those on water heaters. We track emissions of carbon only, rather than of carbon dioxide, because carbon atoms change atomic partners as they move through the carbon cycle, from atmosphere to biosphere or ocean and, on longer time scales, through the rock cycle. To convert a mass of carbon to an equivalent mass of carbon dioxide (thereby including the mass of the 2 oxygen atoms in each molecule) simply multiply by 3.67.

  2. A computational study of particulate emissions from an open pit quarry under neutral atmospheric conditions

    Science.gov (United States)

    Silvester, S. A.; Lowndes, I. S.; Hargreaves, D. M.

    2009-12-01

    The extraction of minerals from surface mines and quarries can produce significant fugitive dust emissions as a result of site activities such as blasting, road haulage, loading, crushing and stockpiling. If uncontrolled, these emissions can present serious environmental, health, safety and operational issues impacting both site personnel and the wider community. The dispersion of pollutant emissions within the atmosphere is principally determined by the background wind systems characterized by the atmospheric boundary layer (ABL). This paper presents an overview of the construction and solution of a computational fluid dynamics (CFD) model to replicate the development of the internal ventilation regime within a surface quarry excavation due to the presence of a neutral ABL above this excavation. This model was then used to study the dispersion and deposition of fugitive mineral dust particles generated during rock blasting operations. The paths of the mineral particles were modelled using Lagrangian particle tracking. Particles of four size fractions were released from five blast locations for eight different wind directions. The study concluded that dependent on the location of the bench blast within the quarry and the direction of the wind, a mass fraction of between 0.3 and 0.6 of the emitted mineral particles was retained within the quarry. The retention was largest when the distance from the blast location to the downwind pit boundary was greatest.

  3. Bacteria in the global atmosphere – Part 2: Modelling of emissions and transport between different ecosystems

    Directory of Open Access Journals (Sweden)

    S. M. Burrows

    2009-05-01

    Full Text Available Bacteria are constantly being transported through the atmosphere, which may have implications for human health, agriculture, cloud formation, and the dispersal of bacterial species. We simulated the global transport of bacterial cells, represented as 1μm diameter spherical solid particle tracers, in a chemistry-climate model. We investigated the factors influencing residence time and distribution of the particles, including emission region, CCN activity and removal by ice-phase precipitation. The global distribution depends strongly on the assumptions made about uptake into cloud droplets and ice. The transport is also affected, to a lesser extent, by the emission region and by season. We examine the potential for exchange of bacteria between ecosystems and obtain rough estimates of the flux from each ecosystem by using an optimal estimation technique, together with a new compilation of available observations described in a companion paper. Globally, we estimate the total emissions of bacteria to the atmosphere to be 1400 Gg per year with an upper bound of 4600 Gg per year, originating mainly from grasslands, shrubs and crops. In order to improve understanding of this topic, more measurements of the bacterial content of the air will be necessary. Future measurements in wetlands, sandy deserts, tundra, remote glacial and coastal regions and over oceans will be of particular interest.

  4. Enhanced emission and light control with tapered plasmonic nanoantennas

    OpenAIRE

    Maksymov, Ivan S.; Davoyan, Arthur R.; Kivshar, Yuri S.

    2011-01-01

    We introduce a design of Yagi-Uda plasmonic nanoantennas for enhancing the antenna gain and achieving control over the angular emission of light. We demonstrate that tapering of antenna elements allows to decrease spacing between the antenna elements tenfold also enhancing its emission directivity. We find the optimal tapering angle that provides the maximum directivity enhancement and the minimum end-fire beamwidth.

  5. Advanced Combustion and Emission Control Technical Team Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-06-01

    The Advanced Combustion and Emission Control (ACEC) Technical Team is focused on removing technical barriers to the commercialization of advanced, high-efficiency, emission-compliant internal combustion (IC) engines for light-duty vehicle powertrains (i.e., passenger car, minivan, SUV, and pickup trucks).

  6. The benefits of China's efforts on gaseous pollutant control indicated by the bottom-up emissions and satellite observation

    Science.gov (United States)

    Xia, Y.; Zhao, Y.

    2015-12-01

    To evaluate the effectiveness of national policies of air pollution control, the emissions of SO2, NOX, CO and CO2 in China are estimated with a bottom-up method from 2000 to 2014, and vertical column densities (VCD) from satellite observation are used to evaluate the inter-annual trends and spatial distribution of emissions and the temporal and spatial patterns of ambient levels of gaseous pollutants across the country. In particular, an additional emission case named STD case, which combines the most recent issued emission standards for specific industrial sources, is developed for 2012-2014. The inter-annual trends in emissions and VCDs match well except for SO2, and the revised emissions in STD case improve the comparison, implying the benefits of emission control for most recent years. Satellite retrieval error, underestimation of emission reduction and improved atmospheric oxidization caused the differences between emissions and VCDs trend of SO2. Coal-fired power plants play key roles in SO2 and NOX emission reduction. As suggested by VCD and emission inventory, the control of CO in 11th five year plan (FYP) period was more effective than that in the 12th FYP period, while the SO2 appeared opposite. As the new control target added in 12th FYP, NOX emissions have been clearly decreased 4.3 Mt from 2011 to 2014, in contrast to the fast growth before 2011. The inter-annual trends in NO2 VCDs has the poorest correlation with vehicle ownership (R=0.796), due to the staged emission standard of vehicles. In developed regions, transportation has become the main pollutants emission source and we prove this by comparing VCDs of NO2 to VCDs of SO2. Moreover, air quality in mega cities has been evaluated based on satellite observation and emissions, and results indicate that Beijing suffered heavily from the emissions from Hebei and Tianjin, while the local emissions tend to dominate in Shanghai.

  7. Laser-induced Field Emission from Tungsten Tip: Optical Control of Emission Sites and Emission Process

    OpenAIRE

    Yanagisawa, H.; Hafner, C; Doná, P; Klöckner, M; Leuenberger, D.; Greber, T.; Osterwalder, J; Hengsberger, M.

    2010-01-01

    Field-emission patterns from a clean tungsten tip apex induced by femtosecond laser pulses have been investigated. Strongly asymmetric field-emission intensity distributions are observed depending on three parameters: (i) the polarization of the light, (ii) the azimuthal, and (iii) the polar orientation of the tip apex relative to the laser incidence direction. In effect, we have realized an ultrafast pulsed field-emission source with site selectivity of a few tens of nanometers. Simulations ...

  8. Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy

    CERN Document Server

    Stevenson, Kevin B; Line, Michael R; Bean, Jacob L; Fortney, Jonathan J; Showman, Adam P; Kataria, Tiffany; Kreidberg, Laura; McCullough, Peter R; Henry, Gregory W; Charbonneau, David; Burrows, Adam; Seager, Sara; Madhusudhan, Nikku; Williamson, Michael H; Homeier, Derek

    2014-01-01

    Exoplanets that orbit close to their host stars are much more highly irradiated than their Solar System counterparts. Understanding the thermal structures and appearances of these planets requires investigating how their atmospheres respond to such extreme stellar forcing. We present spectroscopic thermal emission measurements as a function of orbital phase ("phase-curve observations") for the highly-irradiated exoplanet WASP-43b spanning three full planet rotations using the Hubble Space Telescope. With these data, we construct a map of the planet's atmospheric thermal structure, from which we find large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure at all longitudes. We also derive a Bond albedo of 0.18 +0.07,-0.12 and an altitude dependence in the hot-spot offset relative to the substellar point.

  9. A template of atmospheric molecular oxygen circularly polarized emission for CMB experiments

    CERN Document Server

    Fabbian, Giulio; Gervasi, Massimo; Tartari, Andrea; Zannoni, Mario

    2012-01-01

    We compute the polarized signal from atmospheric molecular oxygen due to Zeeman effect in the Earth magnetic field for various sites suitable for CMB measurements such as South Pole, Dome C (Antarctica) and Atacama desert (Chile). We present maps of this signal for those sites and show their typical elevation and azimuth dependencies. We find a typical circularly polarized signal (V Stokes parameter) level of 50 - 300 \\mu K at 90 GHz when looking at the zenith; Atacama site shows the lowest emission while Dome C site presents the lowest gradient in polarized brightness temperature (0.3 \\mu K/deg at 90 GHz). The accuracy and robustness of the template are tested with respect to actual knowledge of the Earth magnetic field, its variability and atmospheric parameters.

  10. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    Science.gov (United States)

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  11. Do oceanic emissions account for the missing source of atmospheric carbonyl sulfide?

    Science.gov (United States)

    Lennartz, Sinikka; Marandino, Christa A.; von Hobe, Marc; Cortés, Pau; Simó, Rafel; Booge, Dennis; Quack, Birgit; Röttgers, Rüdiger; Ksionzek, Kerstin; Koch, Boris P.; Bracher, Astrid; Krüger, Kirstin

    2016-04-01

    Carbonyl sulfide (OCS) has a large potential to constrain terrestrial gross primary production (GPP), one of the largest carbon fluxes in the carbon cycle, as it is taken up by plants in a similar way as CO2. To estimate GPP in a global approach, the magnitude and seasonality of sources and sinks of atmospheric OCS have to be well understood, to distinguish between seasonal variation caused by vegetation uptake and other sources or sinks. However, the atmospheric budget is currently highly uncertain, and especially the oceanic source strength is debated. Recent studies suggest that a missing source of several hundreds of Gg sulfur per year is located in the tropical ocean by a top-down approach. Here, we present highly-resolved OCS measurements from two cruises to the tropical Pacific and Indian Ocean as a bottom-up approach. The results from these cruises show that opposite to the assumed ocean source, direct emissions of OCS from the tropical ocean are unlikely to account for the missing source. To reduce uncertainty in the global oceanic emission estimate, our understanding of the production and consumption processes of OCS and its precursors, dimethylsulfide (DMS) and carbon disulphide (CS2), needs improvement. Therefore, we investigate the influence of dissolved organic matter (DOM) on the photochemical production of OCS in seawater by considering analysis of the composition of DOM from the two cruises. Additionally, we discuss the potential of oceanic emissions of DMS and CS2 to closing the atmospheric OCS budget. Especially the production and consumption processes of CS2 in the surface ocean are not well known, thus we evaluate possible photochemical or biological sources by analyzing its covariation of biological and photochemical parameters.

  12. Computerized atmospheric trace contaminant control simulation for manned spacecraft

    Science.gov (United States)

    Perry, J. L.

    1993-01-01

    Buildup of atmospheric trace contaminants in enclosed volumes such as a spacecraft may lead to potentially serious health problems for the crew members. For this reason, active control methods must be implemented to minimize the concentration of atmospheric contaminants to levels that are considered safe for prolonged, continuous exposure. Designing hardware to accomplish this has traditionally required extensive testing to characterize and select appropriate control technologies. Data collected since the Apollo project can now be used in a computerized performance simulation to predict the performance and life of contamination control hardware to allow for initial technology screening, performance prediction, and operations and contingency studies to determine the most suitable hardware approach before specific design and testing activities begin. The program, written in FORTRAN 77, provides contaminant removal rate, total mass removed, and per pass efficiency for each control device for discrete time intervals. In addition, projected cabin concentration is provided. Input and output data are manipulated using commercial spreadsheet and data graphing software. These results can then be used in analyzing hardware design parameters such as sizing and flow rate, overall process performance and program economics. Test performance may also be predicted to aid test design.

  13. Parameterization of plume chemistry into large-scale atmospheric models: Application to aircraft NOx emissions

    Science.gov (United States)

    Cariolle, D.; Caro, D.; Paoli, R.; Hauglustaine, D. A.; CuéNot, B.; Cozic, A.; Paugam, R.

    2009-10-01

    A method is presented to parameterize the impact of the nonlinear chemical reactions occurring in the plume generated by concentrated NOx sources into large-scale models. The resulting plume parameterization is implemented into global models and used to evaluate the impact of aircraft emissions on the atmospheric chemistry. Compared to previous approaches that rely on corrected emissions or corrective factors to account for the nonlinear chemical effects, the present parameterization is based on the representation of the plume effects via a fuel tracer and a characteristic lifetime during which the nonlinear interactions between species are important and operate via rates of conversion for the NOx species and an effective reaction rates for O3. The implementation of this parameterization insures mass conservation and allows the transport of emissions at high concentrations in plume form by the model dynamics. Results from the model simulations of the impact on atmospheric ozone of aircraft NOx emissions are in rather good agreement with previous work. It is found that ozone production is decreased by 10 to 25% in the Northern Hemisphere with the largest effects in the north Atlantic flight corridor when the plume effects on the global-scale chemistry are taken into account. These figures are consistent with evaluations made with corrected emissions, but regional differences are noticeable owing to the possibility offered by this parameterization to transport emitted species in plume form prior to their dilution at large scale. This method could be further improved to make the parameters used by the parameterization function of the local temperature, humidity and turbulence properties diagnosed by the large-scale model. Further extensions of the method can also be considered to account for multistep dilution regimes during the plume dissipation. Furthermore, the present parameterization can be adapted to other types of point-source NOx emissions that have to be

  14. VOC from Vehicular Evaporation Emissions: Status and Control Strategy.

    Science.gov (United States)

    Liu, Huan; Man, Hanyang; Tschantz, Michael; Wu, Ye; He, Kebin; Hao, Jiming

    2015-12-15

    Vehicular evaporative emissions is an important source of volatile organic carbon (VOC), however, accurate estimation of emission amounts and scientific evaluation of control strategy for these emissions have been neglected outside of the United States. This study provides four kinds of basic emission factors: diurnal, hot soak, permeation, and refueling. Evaporative emissions from the Euro 4 vehicles (1.6 kg/year/car) are about four times those of U.S. vehicles (0.4 kg/year/car). Closing this emissions gap would have a larger impact than the progression from Euro 3 to Euro 6 tailpipe HC emission controls. Even in the first 24 h of parking, China's current reliance upon the European 24 h diurnal standard results in 508 g/vehicle/year emissions, higher than 32 g/vehicle/year from Tier 2 vehicles. The U.S. driving cycle matches Beijing real-world conditions much better on both typical trip length and average speed than current European driving cycles. At least two requirements should be added to the Chinese emissions standards: an onboard refueling vapor recovery to force the canister to be sized sufficiently large, and a 48-h evaporation test requirement to ensure that adequate purging occurs over a shorter drive sequence. PMID:26599318

  15. Atmospheric emitted radiance interferometer (AERI): Status and the aerosol explanation for extra window region emissions

    Energy Technology Data Exchange (ETDEWEB)

    Revercomb, H.E.; Knuteson, R.O.; Best, F.A.; Dirkx, T.P. [Univ. of Wisconsin, Madison, WI (United States)] [and others

    1996-04-01

    High spectral resolution observations of downwelling emission from 3 to 19 microns have been made by the Atmospheric Emitted Radiance Interferometer (AERI) Prototype at the Southern Great Plains (SGP) Cloud and Radiative Testbed (CART) site for over two years. The spectral data set from AERI provides a basis for improving clear sky radiative transfer; determining the radiative impact of clouds, including the derivation of cloud radiative properties; defining the influences of aerosols in the window regions; and retrieving boundary layer state properties, including temperature, water vapor, and other trace gases. The data stream of radiometrically and spectrally calibrated radiances is routinely provided by Pacific Northwest Laboratory (PNL) to those science teams requesting it, and further information on the instrument and data characteristics is available in the ARM Science Team proceedings for 1993 and 1994 and in several conference publications. This paper describes the AERI status, calibration, field experiment wit a new AERI-01 and schedule, window region emissions, and future AERI plans.

  16. Atmospheric emissions and air quality impacts from natural gas production and use.

    Science.gov (United States)

    Allen, David T

    2014-01-01

    The US Energy Information Administration projects that hydraulic fracturing of shale formations will become a dominant source of domestic natural gas supply over the next several decades, transforming the energy landscape in the United States. However, the environmental impacts associated with fracking for shale gas have made it controversial. This review examines emissions and impacts of air pollutants associated with shale gas production and use. Emissions and impacts of greenhouse gases, photochemically active air pollutants, and toxic air pollutants are described. In addition to the direct atmospheric impacts of expanded natural gas production, indirect effects are also described. Widespread availability of shale gas can drive down natural gas prices, which, in turn, can impact the use patterns for natural gas. Natural gas production and use in electricity generation are used as a case study for examining these indirect consequences of expanded natural gas availability. PMID:24498952

  17. Nitric oxide delta band emission in the earth's atmosphere - Comparison of a measurement and a theory

    Science.gov (United States)

    Rusch, D. W.; Sharp, W. E.

    1981-01-01

    Attention is given to the altitude dependent emission rate in the delta-bands of nitric oxide as measured in the earth's atmosphere at night by a scanning ultraviolet spectrometer. It is noted that the reaction responsible is the two-body association of nitrogen and oxygen atoms. The measurements show a vertical intensity beneath the layer for the delta-band system of 19 R. The horizontal emission rate is found to increase from 70 R at 117 km to 140 R at 150 km. The data are analyzed with a one-dimensional, time-dependent, vertical-transport model of odd nitrogen photochemistry. The calculated and measured intensities agree so long as the quenching of N(2D) by atomic oxygen is near 5 x 10 to the -13 cu cm/sec.

  18. Emission of pollutants in the atmosphere according to oil products quality

    International Nuclear Information System (INIS)

    In this paper the comparison of the environmental protection legal regulations as well as pollutants emission in atmosphere in a most European countries is shown. The air pollution directly depends on both fuel consumption and fuel quality. The fuel quality in Republic of Macedonia gradually is performing and incorporating with anchors European countries. On the other side, energy potentials have no rights to ignore environmental protection, neither environmental protection should be dominated under energy plants. Reciprocal antagonisms should be overtaken through corresponding legislation. (Author)

  19. Spontaneous Emission Control in a Tunable Hybrid Photonic System

    OpenAIRE

    Frimmer, M.; Koenderink, A. F.

    2012-01-01

    We experimentally demonstrate control of the rate of spontaneous emission in a tunable hybrid photonic system that consists of two canonical building blocks for spontaneous emission control, an optical antenna and a mirror, each providing a modification of the local density of optical states (LDOS). We couple fluorophores to a plasmonic antenna to create a superemitter with an enhanced decay rate. In a superemitter analog of the seminal Drexhage experiment we probe the LDOS of a nanomechanica...

  20. Revisiting factors controlling methane emissions from high-Arctic tundra

    DEFF Research Database (Denmark)

    Mastepanov, M.; Sigsgaard, Charlotte; Tagesson, Håkan Torbern;

    2013-01-01

    controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4...... short-term control factors (temperature and water table). Our findings suggest the importance of multiyear studies with a continued focus on shoulder seasons in Arctic ecosystems....

  1. Parameterization of atmospheric longwave emissivity in a mountainous site for all sky conditions

    Directory of Open Access Journals (Sweden)

    J. Herrero

    2012-09-01

    Full Text Available Longwave radiation is an important component of the energy balance of the Earth's surface. The downward component, emitted by the clouds and aerosols in the atmosphere, is rarely measured, and is still not well understood. In mountainous areas, direct observations are even scarcer and the fitting of existing models is often subjected to local parameterization in order to surplus the particular physics of the atmospheric profiles. The influence of clouds makes it even harder to estimate for all sky conditions. This work presents a long-time continuous dataset of high-resolution longwave radiation measured in a weather station at a height of 2500 m a.s.l. in Sierra Nevada, Spain, together with the parameterization of the apparent atmospheric emissivity for clear and cloudy skies resulting from three different schemes. We evaluate the schemes of Brutsaert, and Crawford and Duchon with locally adjusted coefficients and compare them with a completely parametric expression adjusted for these data that takes into account three possible significant atmospheric states related to the cloud cover: clear, completely covered, and partly covered skies. All the parametric expressions are related to the screen-level values of temperature, relative humidity and solar radiation, which can be frequently found in standard weather stations. Unobserved cloudiness measurements needed for Brutsaert scheme for cloudy sky are also parameterized from screen-level measurements. The calibration performed for a 6-yr period at the study site resulted in satisfactory estimations of emissivity for all the analyzed schemes thanks to the local fitting of the parameterizations, with the best achievement found for the completely parametric expression. Further validation of the expressions in two alternative sites showed that the greater accuracy of the latter can also be found in very close sites, while a better performance of the Brutsaert scheme, with a more physical background

  2. Evaluating the contribution of regional emissions to atmospheric concentrations over the UK

    Science.gov (United States)

    Dhomse, Sandip; Wilson, Chris; Basso, Luana; Chipperfield, Martyn; Gloor, Emanuel; O'Doherty, Simon; Stavert, Ann; Young, Dickon; Stanley, Kieran; Grant, Aoife; Helfter, Carole; Mullinger, Neil; Nemitz, Eiko

    2016-04-01

    CO2 is the largest contributor to the anthropogenic greenhouse warming of the Earth's surface. Climate treaties will need verification tools for CO2 emission estimates - primarily those from fossil fuel emissions. Hence, the UK Natural Environment Research Council initiated the "gAs Uk and Global Emissions" (GAUGE) project, aimed at estimating and monitoring the UK's greenhouse gas emissions. GAUGE includes a comprehensive observational programme and a suite of forward and inverse atmospheric modelling tools. Observations include continuous records measured at 6 tall tower sites, regular north-south transects along the east coast of the UK using analysers mounted on ferries and dedicated flights using a BAe-146 aircraft. One of our approaches to estimate CO2 fluxes is based on an analysis of large CO2 deviations from a background baseline using the continuous tower records and the background record from Mace Head, with the deviations being interpreted as signals caused by the UK sources and sinks. First, we will here analyse to what extent the towers record similar / different signals. We will then use tagged tracer simulations with the TOMCAT atmospheric chemistry and transport model to analyse to what extent and under which synoptic the deviations from a background baseline can indeed be attributed to sources and sinks located in the UK. Based on our results we will evaluate this flux estimation approach and make suggestions under which conditions the approach is feasible. Depending on the results of the study we will also propose a simple column budgeting technique to estimate GHG fluxes for the UK using the continuous tower records.

  3. Global atmospheric emissions and transport of polycyclic aromatic hydrocarbons: Evaluation of modeling and transboundary pollution

    Science.gov (United States)

    Shen, Huizhong; Tao, Shu

    2014-05-01

    Global atmospheric emissions of 16 polycyclic aromatic hydrocarbons (PAHs) from 69 major sources were estimated for a period from 1960 to 2030. Regression models and a technology split method were used to estimated country and time specific emission factors, resulting in a new estimate of PAH emission factor variation among different countries and over time. PAH emissions in 2007 were spatially resolved to 0.1° × 0.1° grids based on a newly developed global high-resolution fuel combustion inventory (PKU-FUEL-2007). MOZART-4 (The Model for Ozone and Related Chemical Tracers, version 4) was applied to simulate the global tropospheric transport of Benzo(a)pyrene, one of the high molecular weight carcinogenic PAHs, at a horizontal resolution of 1.875° (longitude) × 1.8947° (latitude). The reaction with OH radical, gas/particle partitioning, wet deposition, dry deposition, and dynamic soil/ocean-air exchange of PAHs were considered. The simulation was validated by observations at both background and non-background sites, including Alert site in Canadian High Arctic, EMEP sites in Europe, and other 254 urban/rural sites reported from literatures. Key factors effecting long-range transport of BaP were addressed, and transboundary pollution was discussed.

  4. An AIS-based approach to calculate atmospheric emissions from the UK fishing fleet

    Science.gov (United States)

    Coello, Jonathan; Williams, Ian; Hudson, Dominic A.; Kemp, Simon

    2015-08-01

    The fishing industry is heavily reliant on the use of fossil fuel and emits large quantities of greenhouse gases and other atmospheric pollutants. Methods used to calculate fishing vessel emissions inventories have traditionally utilised estimates of fuel efficiency per unit of catch. These methods have weaknesses because they do not easily allow temporal and geographical allocation of emissions. A large proportion of fishing and other small commercial vessels are also omitted from global shipping emissions inventories such as the International Maritime Organisation's Greenhouse Gas Studies. This paper demonstrates an activity-based methodology for the production of temporally- and spatially-resolved emissions inventories using data produced by Automatic Identification Systems (AIS). The methodology addresses the issue of how to use AIS data for fleets where not all vessels use AIS technology and how to assign engine load when vessels are towing trawling or dredging gear. The results of this are compared to a fuel-based methodology using publicly available European Commission fisheries data on fuel efficiency and annual catch. The results show relatively good agreement between the two methodologies, with an estimate of 295.7 kilotons of fuel used and 914.4 kilotons of carbon dioxide emitted between May 2012 and May 2013 using the activity-based methodology. Different methods of calculating speed using AIS data are also compared. The results indicate that using the speed data contained directly in the AIS data is preferable to calculating speed from the distance and time interval between consecutive AIS data points.

  5. Atmospheric emissions of anthropogenic lead in Europe: improvements, updates, historical data and projections

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-07-01

    This report provides estimates of lead emissions to the atmosphere in Europe, discriminated by country and by source category within each country. Estimates of past lead emissions are provided for the years 1955, 1965, 1975, 1985, 1990 and 1995. Estimates for 1955-1990 have been improved relatively to earlier estimates for these years provided in 1996 for IIASA, using recently available data. Predictions of future lead emissions are provided for the year 2010. The methodology of estimating emissions is described. (orig.) [German] Dieser Bericht enthaelt Schaetzungen ueber die nationalen Bleiemissionen der europaeischen Laender in die Atmosphaere. Dabei wurden die verschiedenen Arten von Bleiemissionsquellen differenziert beruecksichtigt. Die Schaetzungen liegen fuer die Jahre 1955, 1965, 1975, 1985, 1990 und 1995 vor. Im Vergleich zu den Berechnungen der IIASA 1996 fuer die Jahre 1955-1990, wurden die Schaetzungen in diesem Bericht aufgrund neuer, aktueller Dateninformationen deutlich verbessert. Vorhersagen fuer die zukuenftigen Bleiemissionen in Europa wurden fuer das Jahr 2010 gechaetzt. Zudem enthaelt der Bericht eine ausfuehrliche Beschreibung ueber die den Schaetzungen zugrunde liegenden Methode. (orig.)

  6. Mapping Atmospheric Ammonia Emissions Using a Mobile Quantum Cascade Laser-based Open-path Sensor

    Science.gov (United States)

    Sun, K.; Tao, L.; Miller, D. J.; Khan, M. A.; Zondlo, M. A.

    2012-12-01

    Ammonia (NH3) is a key precursor to atmospheric fine particulate matter, with strong implications for regional air quality and global climate change. Despite the importance of atmospheric ammonia, its spatial/temporal variation is poorly characterized, and the knowledge of its sources, sinks, and transport is severely limited. Existing measurements suggest that traffic exhaust may provide significant amounts of ammonia in urban areas, which cause greater impacts on particulate matter formation and urban air quality. To capture the spatial and temporal variation of ammonia emissions, a portable, low power sensor with high time resolution is necessary. We have developed a portable open-path ammonia sensor with a detection limit of 0.5 ppbv ammonia for 1 s measurements. The sensor has a power consumption of about 60 W and is capable of running on a car battery continuously for 24 hours. An additional laser has been coupled to the sensor to yield concurrent N2O and CO measurements as tracers for determining various sources. The overall sensor prototype fits on a 60 cm × 20 cm aluminum breadboard. Roadside measurements indicated NH3/CO emission ratios of 4.1±5.4 ppbv/ppmv from a fleet of 320 vehicles, which agree with existing on-ramp measurements. Urban measurements in the Baltimore and Washington, DC metropolitan areas have shown significant ammonia mixing ratios concurrent with carbon monoxide levels from the morning and evening rush hours. On-road measurements of our open-path sensor have also been performed continuously from the Midwest to Princeton, NJ including urban areas such as Pittsburgh, tunnels, and relatively clean conditions. The emission ratios of ammonia against CO and/or CO2 help identify the sources and amounts of both urban and agricultural ammonia emissions. Preliminary data from both spatial mapping, monitoring, and vehicle exhaust measurements suggest that urban ammonia emissions from fossil fuel combustion are significant and may provide an

  7. Emission current control system for multiple hollow cathode devices

    Science.gov (United States)

    Beattie, John R. (Inventor); Hancock, Donald J. (Inventor)

    1988-01-01

    An emission current control system for balancing the individual emission currents from an array of hollow cathodes has current sensors for determining the current drawn by each cathode from a power supply. Each current sensor has an output signal which has a magnitude proportional to the current. The current sensor output signals are averaged, the average value so obtained being applied to a respective controller for controlling the flow of an ion source material through each cathode. Also applied to each controller are the respective sensor output signals for each cathode and a common reference signal. The flow of source material through each hollow cathode is thereby made proportional to the current drawn by that cathode, the average current drawn by all of the cathodes, and the reference signal. Thus, the emission current of each cathode is controlled such that each is made substantially equal to the emission current of each of the other cathodes. When utilized as a component of a multiple hollow cathode ion propulsion motor, the emission current control system of the invention provides for balancing the thrust of the motor about the thrust axis and also for preventing premature failure of a hollow cathode source due to operation above a maximum rated emission current.

  8. Finnish National Technology Programme to control GHG emissions

    Energy Technology Data Exchange (ETDEWEB)

    Soimakallio, S.; Ohlstroem, M.; Savolainen, I.

    2003-05-01

    Tekes, the National Technology Agency of Finland funded a three-year technology programme between 1999 and 2002 on Technology and Climate Change (CLIMTECH). Its purpose was to study the development of technologies for controlling greenhouse gas emissions and climate change, the likely demand for them and their future prospects. The programme ended with a final seminar in February 2003. The focus was not only on control of emissions in Finland but also on supporting the export of Finnish technology to reduce emissions elsewhere. The paper gives a summary of the objective, implementation, main results and conclusions of the program. 2 figs.

  9. On Io's control of Jovian decametric radio emissions

    Science.gov (United States)

    Winglee, R. M.

    1986-01-01

    Io's control of Jovian decametric radio emission (DAM) has been attributed to Io distorting the electron distribution in the inner Jovian magnetosphere. Observations of Faraday rotation in DAM are used to determine the properties of the electron distribution before and after its interaction with Io. It is shown that there is an enhancement in the density of the energetic component in the Io plasma torus correlated with certain Jovian longitude. Io's interaction with this energetic component can produce heating of this component. The Io-controlled emission is attributed to enhanced emission from the heated electrons moving down the field lines to Jupiter.

  10. Influence of field emission on the propagation of cylindrical fast ionization wave in atmospheric-pressure nitrogen

    Science.gov (United States)

    Levko, Dmitry; Raja, Laxminarayan L.

    2016-04-01

    The influence of field emission of electrons from surfaces on the fast ionization wave (FIW) propagation in high-voltage nanosecond pulse discharge in the atmospheric-pressure nitrogen is studied by a one-dimensional Particle-in-Cell Monte Carlo Collisions model. A strong influence of field emission on the FIW dynamics and plasma parameters is obtained. Namely, the accounting for the field emission makes possible the bridging of the cathode-anode gap by rather dense plasma (˜1013 cm-3) in less than 1 ns. This is explained by the generation of runaway electrons from the field emitted electrons. These electrons are able to cross the entire gap pre-ionizing it and promoting the ionization wave propagation. We have found that the propagation of runaway electrons through the gap cannot be accompanied by the streamer propagation, because the runaway electrons align the plasma density gradients. In addition, we have obtained that the field enhancement factor allows controlling the speed of ionization wave propagation.

  11. Record high peaks in PCB concentrations in the Arctic atmosphere due to long-range transport of biomass burning emissions

    OpenAIRE

    Eckhardt, S; Breivik, K.; S. Mano; A. Stohl

    2007-01-01

    International audience; Soils and forests in the boreal region of the Northern Hemisphere are recognised as having a large capacity for storing air-borne Persistent Organic Pollutants (POPs), such as the polychlorinated biphenyls (PCBs). Following reductions of primary emissions of various legacy POPs, there is an increasing interest and debate about the relative importance of secondary re-emissions on the atmospheric levels of POPs. In spring of 2006, biomass burning emissions from agricultu...

  12. Quantifying the uncertainties of a bottom-up emission inventory of anthropogenic atmospheric pollutants in China

    Directory of Open Access Journals (Sweden)

    Y. Zhao

    2010-11-01

    Carlo simulation yields narrowed estimates of uncertainties compared to previous bottom-up emission studies, the results are not always consistent with those derived from satellite observations. The results thus represent an incremental research advance; while the analysis provides current estimates of uncertainty to researchers investigating Chinese and global atmospheric transport and chemistry, it also identifies specific needs in data collection and analysis to improve on them. Strengthened quantification of emissions of the included species and other, closely associated ones – notably CO2, generated largely by the same processes and thus subject to many of the same parameter uncertainties – is essential not only for science but for the design of policies to redress critical atmospheric environmental hazards at local, regional, and global scales.

  13. Optical emission spectroscopy of microwave-plasmas at atmospheric pressure applied to the growth of organosilicon and organotitanium nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Kilicaslan, A.; Levasseur, O.; Roy-Garofano, V.; Profili, J.; Moisan, M.; Stafford, L., E-mail: luc.stafford@umontreal.ca [Département de Physique, Université de Montréal, Montréal, Québec H3C 3J7 (Canada); Côté, C.; Sarkissian, A. [Plasmionique Inc., Varennes, Québec J3X 1S2 (Canada)

    2014-03-21

    An atmospheric-pressure plasma sustained by an electromagnetic surface wave (SW) in the microwave regime combined with a bubbler/flash evaporator for the injection of liquid precursors was used to produce organosilicon and organotitanium nanopowders. Following the addition of hexamethyldisiloxane (HMDSO) vapors in the nominally pure argon plasma, optical emission spectra revealed the apparition of strong C{sub 2} molecular bands along with Si and Balmer H emission lines. Such features were not observed in our atmospheric-pressure Ar/HMDSO discharges controlled by dielectric barriers, indicating that microwave plasmas are characterized by much higher fragmentation levels of the precursors due to much higher electron densities. Emission spectra from the Ar/HMDSO SW plasma further showed a high-intensity continuum, the intensity of which decreased with time as powders started to form on the discharge tube walls. In presence of titanium isopropoxide (TTIP) vapors in the nominally pure Ar plasma, the emission was dominated by Ar and Ti lines, with no trace of carbon and no continuum. Fourier-Transform Infrared (FTIR) Spectroscopy of the powders formed in Ar/HMDSO plasmas showed very strong Si-(CH{sub 3}){sub x} and O-Si-(CH{sub 3}){sub x} bands, which is consistent with the formation of silicon oxycarbide. Transmission Electron Microscopy (TEM) further showed tube and sheet-like nanofeatures as well as larger structures consisting of agglomerated primary clusters. On the other hand, introduction of O{sub 2} in Ar/HMDSO plasmas produced only round-like nanoparticles with strong Si-O-Si bands and no trace of carbon, consistent with the formation of SiO{sub x}. The average size of the silica nanoparticles was 50 nm. FTIR spectra of powders formed in Ar/TTIP plasmas showed strong Ti-O signals, even without the addition of O{sub 2} in the gas phase. Corresponding TEM analysis showed nano- and agglomerated features comparable to those obtained in Ar/HMDSO although the

  14. Optical emission spectroscopy of microwave-plasmas at atmospheric pressure applied to the growth of organosilicon and organotitanium nanopowders

    Science.gov (United States)

    Kilicaslan, A.; Levasseur, O.; Roy-Garofano, V.; Profili, J.; Moisan, M.; Côté, C.; Sarkissian, A.; Stafford, L.

    2014-03-01

    An atmospheric-pressure plasma sustained by an electromagnetic surface wave (SW) in the microwave regime combined with a bubbler/flash evaporator for the injection of liquid precursors was used to produce organosilicon and organotitanium nanopowders. Following the addition of hexamethyldisiloxane (HMDSO) vapors in the nominally pure argon plasma, optical emission spectra revealed the apparition of strong C2 molecular bands along with Si and Balmer H emission lines. Such features were not observed in our atmospheric-pressure Ar/HMDSO discharges controlled by dielectric barriers, indicating that microwave plasmas are characterized by much higher fragmentation levels of the precursors due to much higher electron densities. Emission spectra from the Ar/HMDSO SW plasma further showed a high-intensity continuum, the intensity of which decreased with time as powders started to form on the discharge tube walls. In presence of titanium isopropoxide (TTIP) vapors in the nominally pure Ar plasma, the emission was dominated by Ar and Ti lines, with no trace of carbon and no continuum. Fourier-Transform Infrared (FTIR) Spectroscopy of the powders formed in Ar/HMDSO plasmas showed very strong Si-(CH3)x and O-Si-(CH3)x bands, which is consistent with the formation of silicon oxycarbide. Transmission Electron Microscopy (TEM) further showed tube and sheet-like nanofeatures as well as larger structures consisting of agglomerated primary clusters. On the other hand, introduction of O2 in Ar/HMDSO plasmas produced only round-like nanoparticles with strong Si-O-Si bands and no trace of carbon, consistent with the formation of SiOx. The average size of the silica nanoparticles was 50 nm. FTIR spectra of powders formed in Ar/TTIP plasmas showed strong Ti-O signals, even without the addition of O2 in the gas phase. Corresponding TEM analysis showed nano- and agglomerated features comparable to those obtained in Ar/HMDSO although the average size of the titanate nanoparticles was smaller

  15. International Space Station Atmosphere Control and Supply, Atmosphere Revitalization, and Water Recovery and Management Subsystem - Verification for Node 1

    Science.gov (United States)

    Williams, David E.

    2007-01-01

    The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 ACS, AR, and WRM design and detailed Element Verification methodologies utilized during the Qualification phase for Node 1.

  16. Radiative forcing associated with particulate carbon emissions resulting from the use of mercury control technology.

    Science.gov (United States)

    Lin, Guangxing; Penner, Joyce E; Clack, Herek L

    2014-09-01

    Injection of powdered activated carbon (PAC) adsorbents into the flue gas of coal fired power plants with electrostatic precipitators (ESPs) is the most mature technology to control mercury emissions for coal combustion. However, the PAC itself can penetrate ESPs to emit into the atmosphere. These emitted PACs have similar size and optical properties to submicron black carbon (BC) and thus could increase BC radiative forcing unintentionally. The present paper estimates, for the first time, the potential emission of PAC together with their climate forcing. The global average maximum potential emissions of PAC is 98.4 Gg/yr for the year 2030, arising from the assumed adoption of the maximum potential PAC injection technology, the minimum collection efficiency, and the maximum PAC injection rate. These emissions cause a global warming of 2.10 mW m(-2) at the top of atmosphere and a cooling of -2.96 mW m(-2) at the surface. This warming represents about 2% of the warming that is caused by BC from direct fossil fuel burning and 0.86% of the warming associated with CO2 emissions from coal burning in power plants. Its warming is 8 times more efficient than the emitted CO2 as measured by the 20-year-integrated radiative forcing per unit of carbon input (the 20-year Global Warming Potential). PMID:25093939

  17. Environmental controls over methanol production, emission, and δ13C values from Lycopersicon esculentum

    Science.gov (United States)

    Oikawa, P.; Giebel, B. M.; Mak, J. E.; Riemer, D. D.; Swart, P. K.; Lerdau, M.

    2009-12-01

    Phytogenic methanol is the dominant source of methanol to the atmosphere, where it is the second most abundant organic compound. Beyond methanol’s role in atmospheric chemistry, it is an indicator of plant function and is linked to plant wound response. Methanol emissions are considered to be a by-product of cell wall expansion and, more specifically, the demethylation of pectin by pectin methylesterase (PME) in cell walls. Production of methanol was investigated in mature and immature tomato Lycopersicon esculentum via measurement of methanol flux, foliar PME activity, and methanol extraction from leaf, root, and stem tissues. δ13C values for mature and immature methanol emissions were also measured using a GC-IRMS system. Environmental control over methanol production and emission was studied by changing temperature and light while holding stomatal conductance constant. As seen previously, mature leaf methanol emissions were significantly less than immature emissions. Surprisingly, preliminary results suggest mature leaf methanol production to be similar to immature leaves, indicating an enhanced metabolic sink for methanol in mature leaves. These data enhance our understanding of methanol production, a term which is not well constrained in current methanol flux models.

  18. [The response of forest ecosystems to reduction in industrial atmospheric emission in the Kola Subarctic].

    Science.gov (United States)

    Koptsik, G N; Koptsik, S V; Smirnova, I E; Kudryavtseva, A D; Turbabina, K A

    2016-01-01

    In spite of reduction in atmospheric emission, current state of forest ecosystems within the impact zone of Severonickel enterprise still reflects the entire spectrum of anthropogenic digression stages. As the distance to the enterprise grows shorter, structural-functional changes in forest communities are manifested in dropping out of mosses and lichens, replacement of undershrub by Poaceae, worsening of timber stand and undergrowth conditions and their progressive dying-off, and, as a result, in forming of anthropogenic wastelands. Alterations of elemental composition of fir bark and needles due to exposure to pollutants consist in accumulation of nickel, copper, cobalt, arsenic, and sulfur along with depletion of calcium, magnesium, manganese, and zinc. According to the data obtained by correlation and multiparameter analyses, the accumulation of heavy metals in fir organs is closely related to the increasing of their concentration in root-inhabited soil layers as the distance to the pollution source is getting shorter. By comparison with the background fir grove, concentration of available compounds of nickel and copper in the ground litter of open fir-birch woodland near the enterprise increases by the factor of 30-60, reaching up 280 and 130 mg/kg respectively. With the increasing of anthropogenic stress, the ground litter becomes depleted of available calcium, magnesium, potassium, manganese, and zinc. For the first time, the coupled dynamics of vegetation and soil state in fir forests as a response to reduction in atmospheric emission is tracked back. The most distinguishable response to the reduction appears to be the development of small-leaved plants' young growth within the impact zone. For the last decade, concentration of nickel in fir needles and in ground litter has reduced by the factor of 1.2-2. As for copper, its concentration in needles has reduced by the factor of 2-4, though in ground litter remains the same. By comparison with the period of

  19. VOC emission into the atmosphere by trees and leaf litter in Polish forests

    Science.gov (United States)

    Isidorov, V.; Smolewska, M.; Tyszkiewicz, Z.

    2009-04-01

    It is generally recognized at present that the vegetation of continents is the principal source of reactive volatile organic compounds (VOC) of the atmosphere. The upper limit of the evaluation of global phytogenic VOC is 1100-1500 Tg/yr (Isidorov, 1990; Guenther et al., 1995). Although these global evaluations showing the place of phytogenic emission among of other VOC sources are important, evaluations for individual countries are also very important. This poster represents the results of the estimation of VOC emission from Polish forests. Calculations took into account the composition and age of forests. According to our estimation, the total VOC emission by the arboreal vegetation differs from 190 to 750 kt/yr, depending of weather conditions in different years. There are only few studies conducted on decaying plant material as a source of atmospheric VOCs, but still they are able to give evidence of the importance of this source. For Polish forests, the litter mass is estimated to be (16-19)106 t/yr. These organic materials undergo decomposition by mesofauna and microorganisms. In these processes volatile organic compounds (VOC) stored in the litter and secondary metabolites of litter-destroying fungi are emitted into the atmosphere. The scale of the phenomenon makes leaf litter an important VOC source in the atmosphere. The filling of numerous gaps in researches of VOC emissions from decomposing leaf litter demands carrying out of long term field experiments in various climatic conditions. In this communication we report also the results of 3.5-year experiment on qualitative and quantitative GC-MS investigations of VOC emitted into the gas phase from leaves litter of some species of deciduous and coniferous trees of Polish forests. Apart from terpenes and their oxygenated derivatives, which are usual in plant tissues, leaf litter intensively emits vast amounts of lower alcohols and carbonyl compounds. We suppose that these volatile substances are products

  20. Atmospheric transmission and thermal background emission in the mid-infrared at Mauna Kea

    Science.gov (United States)

    Otárola, A.; Richter, M.; Packham, C.; Chun, M.

    2015-04-01

    We present results of a preliminary study intended to quantitatively estimate the atmospheric transmission and thermal background emission in the mid-infrared (MIR), 7 μm - 26 μm, at the 13N TMT site in Mauna Kea. This is in the interest of supporting the planning of MIR instrumentation for the posible second-generation of astronomical instruments for the Thirty Meter Telescope (TMT) project. Mauna Kea, located at high altitude (4,050 m above sea level), enjoys natural conditions that make it an outstanding location for astronomical observations in the mid-infrared. The goal of this work is to produce a dataset and model that shows the atmospheric transmission and thermal emission for two cases of precipitable water vapor (PWV), a low value of 0.3 mm, and at 1.5 mm which represent near median conditions at the site. Besides, and driven by the interest of the MIR community to exploit the daily twilight times, we look at the specific atmospheric conditions around twilight as a function of season. The best conditions are found for cold and dry winter days, and in particular the morning twilight offers the best conditions. The analysis of PWV data, shows the median value for the site (all year conditions between 6:00 PM and 7:30AM) is 1.8 mm and that periods of water vapor lower than 1.0 mm are common, these supports the opportunity and discovery potential of the TMT project in the mid-infrared bands.

  1. Quantifying Methane Emissions from the Arctic Ocean Seabed to the Atmosphere

    Science.gov (United States)

    Platt, Stephen; Pisso, Ignacio; Schmidbauer, Norbert; Hermansen, Ove; Silyakova, Anna; Ferré, Benedicte; Vadakkepuliyambatta, Sunil; Myhre, Gunnar; Mienert, Jürgen; Stohl, Andreas; Myhre, Cathrine Lund

    2016-04-01

    Large quantities of methane are stored under the seafloor in the shallow waters of the Arctic Ocean. Some of this is in the form of hydrates which may be vulnerable to deomposition due to surface warming. The Methane Emissions from Arctic Ocean to Atmosphere MOCA, (http://moca.nilu.no/) project was established in collaboration with the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE, https://cage.uit.no/). In summer 2014, and summer and autumn 2015 we deployed oceanographic CTD (Conductivity, Temperature, Depth) stations and performed state-of-the-art atmospheric measurements of CH4, CO2, CO, and other meteorological parameters aboard the research vessel Helmer Hanssen west of Prins Karl's Forland, Svalbard. Air samples were collected for isotopic analysis (13C, 2H) and quantification of other hydrocarbons (ethane, propane, etc.). Atmospheric measurements are also available from the nearby Zeppelin Observatory at a mountain close to Ny-Ålesund, Svalbard. We will present data from these measurements that show an upper constraint of the methane flux in measurement area in 2014 too low to influence the annual CH4 budget. This is further supported by top-down constraints (maximum release consistent with observations at the Helmer Hansen and Zeppelin Observatory) determined using FLEXPART foot print sensitivities and the OsloCTM3 model. The low flux estimates despite the presence of active seeps in the area (numerous gas flares were observed using echo sounding) were apparently due to the presence of a stable ocean pycnocline at ~50 m.

  2. Sensitivity of Biomarkers to Changes in Chemical Emissions in the Earth's Proterozoic Atmosphere

    CERN Document Server

    Grenfell, John Lee; von Paris, Philip; Godolt, Mareike; Hedelt, Pascal; Patzer, Beate; Stracke, Barbara; Rauer, Heike

    2010-01-01

    The search for life beyond the Solar System is a major activity in exoplanet science. However, even if an Earth-like planet were to be found, it is unlikely to be at a similar stage of evolution as the modern Earth. It is therefore of interest to investigate the sensitivity of biomarker signals for life as we know it for an Earth-like planet but at earlier stages of evolution. Here, we assess biomarkers i.e. species almost exclusively associated with life, in present-day and in 10% present atmospheric level oxygen atmospheres corresponding to the Earth's Proterozoic period. We investigate the impact of proposed enhanced microbial emissions of the biomarker nitrous oxide, which photolyses to form nitrogen oxides which can destroy the biomarker ozone. A major result of our work is regardless of the microbial activity producing nitrous oxide in the early anoxic ocean, a certain minimum ozone column can be expected to persist in Proterozoic-type atmospheres due to a stabilising feedback loop between ozone, nitrou...

  3. Experience curves for power plant emission control technologies

    OpenAIRE

    Rubin, Edward S.; Yeh, Sonia; Hounshell, David A

    2007-01-01

    This paper examines past experience in controlling emissions of sulphur dioxide (SO2) and nitrogen oxides (NOx) from coal-fired electric power plants. In particular, we focus on US and worldwide experience with two major environmental control technologies: flue gas desulphurisation (FGD) systems for SO2 control and selective catalytic reduction (SCR) systems for NOx control. We quantitatively characterise historical trends in the deployment and costs of these technologies over the past 30 yea...

  4. Controlled Microdroplet Transport in an Atmospheric Pressure Microplasma

    CERN Document Server

    Maguire, P D; Kelsey, C P; Bingham, A; Montgomery, E P; Bennet, E D; Potts, H E; Rutherford, D; McDowell, D A; Diver, D A; Mariotti, D

    2015-01-01

    We report the controlled injection of near-isolated micron-sized liquid droplets into a low temperature He-Ne steady-state rf plasma at atmospheric pressure. The H2O droplet stream is constrained within a 2 mm diameter quartz tube. Imaging at the tube exit indicates a log-normal droplet size distribution with an initial count mean diameter of 15 micrometers falling to 13 micrometers with plasma exposure. The radial velocity profile is approximately parabolic indicating near laminar flow conditions with the majority of droplets travelling at >75% of the local gas speed and having a plasma transit time of < 100 microseconds. The maximum gas temperature, determined from nitrogen spectral lines, was below 400 K and the observed droplet size reduction implies additional factors beyond standard evaporation, including charge and surface chemistry effects. The successful demonstration of controlled microdroplet streams opens up possibilities for gas-phase microreactors and remote delivery of active species for pla...

  5. Control strategies for vehicular NOx emissions in Guangzhou, China

    International Nuclear Information System (INIS)

    Guangzhou is a city in southern China that has experienced very rapid economic development in recent years. The city's air has very high concentrations of various pollutants, including sulphur dioxide (SO2, oxides of nitrogen (NOx), ozone (O3) and particulate. This paper reviews the changes in air quality in the city over the past 15 years, and notes that a serious vehicular-related emissions problem has been superimposed on the traditional coal-burning problem evident in most Chinese cities. As NOx concentrations have increased, oxidants and photochemical smog now interact with the traditional SO2 and particulate pollutants, leading to increased health risks and other environmental concerns. Any responsible NOx control strategy for the city must include vehicle emission control measures. This paper reviews control strategies designed to abate vehicle emissions to fulfill the city's air quality improvement target in 2010. A cost-effectiveness analysis suggests that, while NOx emission control is expensive, vehicular emission standards could achieve a relatively sizable emissions reduction at reasonable cost. To achieve the 2010 air quality target of NOx, advanced implementation of EURO3 standards is recommended, substituting for the EURO2 currently envisioned in the national regulations Related technical options, including fuel quality improvements and inspection/maintenance (I/M) upgrades (ASM or IM240) are assessed as well. (author)

  6. Low-dimensional models for the estimation of anthropogenic CO2 emissions from atmospheric observations

    Science.gov (United States)

    van Bloemen Waanders, B.; Ray, J.; McKenna, S. A.; Yadav, V.; Michalak, A. M.

    2011-12-01

    The estimation of anthropogenic fossil fuel emissions using atmospheric observations of CO2 has recently attracted increasing interest due to its relevance to monitoring of CO2 mitigation treaties and programs. To date, techniques to perform large-scale inversions had primarily been developed within the context of understanding biospheric and oceanic fluxes. Such fluxes tend to vary relatively smoothly in space and time, making it possible to use multiGaussian models to parameterize and regularize such inversions, predicated on limited measurements of CO2 concentrations. However, the spatial distribution of anthropogenic emissions is non-stationary and multiscale, and therefore makes the use of multiGaussians models less suitable. Thus, a need exists to identify how anthropogenic emissions may be represented in a low-dimensional manner (i.e., with few parameters), for use in top-down estimation. Certain aspects of the spatial extent of anthropogenic emissions can be represented using easily measurable proxies such as nightlights, population density and GDP; in fact, fossil fuel inventories regularly use them to disaggregate regional emission budgets to finer spatial resolutions. However, such proxies can also be used to construct a priori models for anthropogenic emissions, which can then be updated, with data, through inverse modeling. In this presentation, we compare 3 low-dimensional parameterizations to characterize anthropogenic sources. The models are derived from images of nightlights over the continental USA, but adopt different arguments to achieve their dimensionality reduction. In the first model, we threshold nightlights and fit bivariate Gaussian kernels over clusters to represent emission sources; the emission field is modeled as a weighted sum of the kernels. The second approach models emissions as a weighted superposition of a filtered nightlight-distribution and a multiresolution defect, modeled with Haar wavelet. The nightlight-based methods

  7. The possible influence of volcanic emissions on atmospheric aerosols in the city of Colima, Mexico.

    Science.gov (United States)

    Miranda, Javier; Zepeda, Francisco; Galindo, Ignacio

    2004-01-01

    An elemental composition study of atmospheric aerosols from the City of Colima, in the Western Coast of Mexico, is presented. Samples of PM(15)-PM(2.5) and PM(2.5) were collected with Stacked Filter Units (SFU) of the Davis design, in urban and rural sites, the latter located between the City of Colima and the Volcán de Colima, an active volcano. Elemental analyses were carried out using Particle Induced X-ray Emission (PIXE). The gravimetric mass concentrations for the fine fraction were slightly higher in the urban site, while the mean concentrations in the coarse fraction were equal within the uncertainties. High Cl contents were determined in the coarse fraction, a fact also observed in emissions from the Volcán de Colima by other authors. In addition to average elemental concentrations, cluster analysis based on elemental contents was performed, with wind speed and direction data, showing that there is an industrial contributor to aerosols North of the urban area. Moreover, a contribution from the volcanic emissions was identified from the grouping of S, Cl, Cu, and Zn, elements associated to particles emitted by the Volcán de Colima. PMID:14568726

  8. The possible influence of volcanic emissions on atmospheric aerosols in the city of Colima, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Javier; Zepeda, Francisco; Galindo, Ignacio

    2004-01-01

    An elemental composition study of atmospheric aerosols from the City of Colima, in the Western Coast of Mexico, is presented. Samples of PM{sub 15}-PM{sub 2.5} and PM{sub 2.5} were collected with Stacked Filter Units (SFU) of the Davis design, in urban and rural sites, the latter located between the City of Colima and the Volcan de Colima, an active volcano. Elemental analyses were carried out using Particle Induced X-ray Emission (PIXE). The gravimetric mass concentrations for the fine fraction were slightly higher in the urban site, while the mean concentrations in the coarse fraction were equal within the uncertainties. High Cl contents were determined in the coarse fraction, a fact also observed in emissions from the Volcan de Colima by other authors. In addition to average elemental concentrations, cluster analysis based on elemental contents was performed, with wind speed and direction data, showing that there is an industrial contributor to aerosols North of the urban area. Moreover, a contribution from the volcanic emissions was identified from the grouping of S, Cl, Cu, and Zn, elements associated to particles emitted by the Volcan de Colima. - Elemental analyses of PM{sub 15} in the City of Colima, Mexico, were done to identify possible contributions from the Volcan de Colima, an active volcano.

  9. Heterogeneous doped one-dimensional photonic crystal with low emissivity in infrared atmospheric window

    Science.gov (United States)

    Miao, Lei; Shi, Jiaming; Wang, Jiachun; Zhao, Dapeng; Chen, Zongsheng; Wang, Qichao

    2016-05-01

    The characteristic matrix method in thin-film optical theory was used to calculate heterogeneous doped one-dimensional photonic crystals (1-D PCs), which were fabricated by alternate deposition of Te, ZnSe, and Si materials on a silicon wafer. The heterogeneous structure was adopted to broaden the photonic band gap, within which the low reflection valley was achieved by doping. Infrared spectrum tests showed that the average emissivities of the 1-D PC were 0.0845 and 0.281, corresponding, respectively, to the bands of 3 to 5 and 8 to 14 μm. Moreover, the emissivity was 0.45 over the 5 to 8 μm nonatmospheric window, and the reflectivity was 0.28 at the wavelength of 10.6 μm. The results indicated that the heterogeneous doped 1-D PC was able to selectively achieve low emissivities over infrared atmospheric windows and a low reflectivity for the CO2 laser, which exhibited remarkable competence in compatible infrared and laser stealth applications.

  10. Quantifying Black Carbon emissions in high northern latitudes using an Atmospheric Bayesian Inversion

    Science.gov (United States)

    Evangeliou, Nikolaos; Thompson, Rona; Stohl, Andreas; Shevchenko, Vladimir P.

    2016-04-01

    Black carbon (BC) is the main light absorbing aerosol species and it has important impacts on air quality, weather and climate. The major source of BC is incomplete combustion of fossil fuels and the burning of biomass or bio-fuels (soot). Therefore, to understand to what extent BC affects climate change and pollutant dynamics, accurate knowledge of the emissions, distribution and variation of BC is required. Most commonly, BC emission inventory datasets are built by "bottom up" approaches based on activity data and emissions factors, but these methods are considered to have large uncertainty (Cao et al, 2006). In this study, we have used a Bayesian Inversion to estimate spatially resolved BC emissions. Emissions are estimated monthly for 2014 and over the domain from 180°W to 180°E and 50°N to 90°N. Atmospheric transport is modeled using the Lagrangian Particle Dispersion Model, FLEXPART (Stohl et al., 1998; 2005), and the inversion framework, FLEXINVERT, developed by Thompson and Stohl, (2014). The study domain is of particular interest concerning the identification and estimation of BC sources. In contrast to Europe and North America, where BC sources are comparatively well documented as a result of intense monitoring, only one station recording BC concentrations exists in the whole of Siberia. In addition, emissions from gas flaring by the oil industry have been geographically misplaced in most emission inventories and may be an important source of BC at high latitudes since a significant proportion of the total gas flared occurs at these high latitudes (Stohl et al., 2013). Our results show large differences with the existing BC inventories, whereas the estimated fluxes improve modeled BC concentrations with respect to observations. References Cao, G. et al. Atmos. Environ., 40, 6516-6527, 2006. Stohl, A. et al. Atmos. Environ., 32(24), 4245-4264, 1998. Stohl, A. et al. Atmos. Chem. Phys., 5(9), 2461-2474, 2005. Stohl, A. et al. Atmos. Chem. Phys., 13

  11. China's Total Emission Control Policy: a Critical Review

    Institute of Scientific and Technical Information of China (English)

    Ge Chazhong; Chen Ji; Wang Jinnan; Long Feng

    2009-01-01

    As part of a comprehensive environmental management system, many countries establish emission control targets for mass emissions of a pollutant.Such targets are often the key objective of an environmental policy, such as an emission trading program.In China, however, it is more than just an objective of one particular policy; it has become a concept that has influenced many national environmental policies and activities.The objective of this article is to review the implementation of the total emission control policy in the past 10 years and explore emerging issues in its implementa-tion.The article has three sections: a summary of the implementa-tion experience, issues with the design and implementation of the policy, and policy recommendations.

  12. CONTROL OF SULFUR EMISSIONS FROM OIL SHALE RETORTS

    Science.gov (United States)

    The objectives of this study were to determine the best available control technology (BACT) for control of sulfur emissions from oil shale processing facilities and then to develop a design for a mobile slipstream pilot plant that could be used to test and demonstrate that techno...

  13. Adjoint-based sensitivity and feedback control of noise emission

    OpenAIRE

    Airiau, Christophe

    2013-01-01

    A LQR control is performed on a reduce order model built from Direct Numerical Simulation of an open cavity flow, for a 2D geometry, and in the aim of controlling noise emission. A -10 dB achievement is demonstrated

  14. Air pollution control techniques and a case study of industrial air emissions

    International Nuclear Information System (INIS)

    Air pollutants are the most dangerous type of pollution and they effect our environment the worst. The main air pollutants are CO/sub 2/, CO, NOx, SOx and particulate matter. These pollutants are causing some major environmental and health concerns. There are number of techniques to control these emissions to the atmosphere. The flue gas data of boilers and generators from ICI polyester industry is also included in this paper. The techniques in use to control the pollutants are discussed. One of the most common techniques is the switching of the fuel. The Natural gas emits almost 30 percent less carbon dioxide than oil, and just under 45 percent less carbon dioxide than coal. Emissions of particulates from natural gas combustion are 90 percent lower than from the combustion of oil, and 99 percent lower than burning coal. Natural gas emits virtually no sulfur dioxide, and upto 80 percent less nitrogen oxides than the combustion of coal. Similarly, use of compressed natural gas in vehicle reduces the amount of these emissions considerably. The other methods for the control and reduction of these emissions are combustion control techniques, Flue gas treatment and Fuel re-burning. NOx can be reduced considerably by combustion control techniques like Low excess air, staged air combustion, staged fuel combustion, external flue gas recirculation, Fuel induced recirculation and steam/water injection. The flue gas treatments like selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) are also used for reduction of NOx. (author)

  15. Synergistic control of CO2 emissions by fish and nutrients in a humic tropical lake.

    Science.gov (United States)

    Marotta, Humberto; Duarte, Carlos M; Guimarães-Souza, Breno A; Enrich-Prast, Alex

    2012-03-01

    Using experimental mesocosms, we tested the strength of bottom-up controls by nutrients and top-down controls by an omnivorous fish (Hyphessobrycon bifasciatus; family Characidae), and the interaction between them on the CO(2) partial pressure (pCO(2)) in the surface waters of a tropical humic lake (Lake Cabiúnas, Brazil). The experiment included the addition of nutrients and fish to the mesocosms in a factorial design. Overall, persistent CO(2) emissions to the atmosphere, supported by an intense net heterotrophy, were observed in all treatments and replicates over the 6-week study period. The CO(2) efflux (average ± standard error) integrated over the experiment was similar among the control mesocosms and those receiving only fish or only nutrients (309 ± 2, 303 ± 16, and 297 ± 17 mmol CO(2) m(-2) day(-1), respectively). However, the addition of nutrients in the presence of fish resulted in a high algal biomass and daytime net autotrophy, reducing the CO(2) emissions by 35% (by 193 ± 7 mmol CO(2) m(-2) day(-1)). These results indicate that high CO(2) emissions persist following the eutrophication of humic waters, but that the magnitude of these emissions might depend on the structure of the food web. In conclusion, fish and nutrients may act in a synergistic manner to modulate persistent CO(2) emissions from tropical humic lakes.

  16. CONTROL OF GAS EMISSION AT COAL FACE IN CHINA

    Institute of Scientific and Technical Information of China (English)

    俞启香; 付建华

    1991-01-01

    All the underground coal mines in China are gassy mines. The gas emission at coal face increasingly grows with the increase of working depth and coal output,for example,the gas emission at a full mechanized coal face of mine No.2 at Yongquan with a daily output of 2,000t/d is up to 66--72m3/min. Special gas emission phenomena such as gas blowout, gas and coal outburst etc. have occurred at some faces, which threatens the safe production of face, obstructs the growth of productivity and limits the full play of mechanized equipment. In this paper, gas at face is divided, according to its origin, into three constituents, namely, coming from the coal wall, mined coal and goaf; and a formula for calculation is given. Also, the characteristics of the variation of gas emission at coal face, and thesinfluence of mining sequence of a group of seams and supplied air quantity on the gas emission are discussed. Furthermore, based on the regularity of gas emission st coal face from the above three sources, and on the experiences of years, three principles on controlling gas emission at coal face are presented, that are managing the gas on classification basis, harnessing each source separately and comprehensive prevention and control. Finally, technical measures for prevention and treatment of the accumulation of gas in the upper corner of face, at the working place of coal-winning machine and in the bottom trough of conveyor are introduced.

  17. A Comparative Energetic Analysis of Active and Passive Emission Control Systems Adopting Standard Emission Test Cycles

    OpenAIRE

    Angelo Algieri; Mario Amelio; Pietropaolo Morrone

    2012-01-01

    The present work aims at analysing and comparing the thermal performances of active and passive aftertreatment systems. A one-dimensional transient model has been developed in order to evaluate the heat exchange between the solid and the exhaust gas and to estimate the energy effectiveness of the apparatus. Furthermore, the effect of the engine operating conditions on the performances of emission control systems has been investigated considering standard emission test cycles. The analysis has...

  18. Controlling spontaneous emission with plasmonic optical patch antennas

    OpenAIRE

    Belacel, C.; Habert, B.; Bigourdan, F.; Marquier, F.; Hugonin, J.-P.; Michaelis de Vasconcellos, S.; Lafosse, X.; Coolen, L; Schwob, C.; Javaux, C; Dubertret, B.; Greffet, J. -J.; Senellart, P.; Maitre, A.

    2012-01-01

    We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk 30 nm above a thick gold layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending of the antenna size. Considering the double...

  19. Positional control of plasmonic fields and electron emission

    Energy Technology Data Exchange (ETDEWEB)

    Word, R. C.; Fitzgerald, J. P. S.; Könenkamp, R., E-mail: rkoe@pdx.edu [Department of Physics, Portland State University, 1719 SW 10th Avenue, Portland, Oregon 97201 (United States)

    2014-09-15

    We report the positional control of plasmonic fields and electron emission in a continuous gap antenna structure of sub-micron size. We show experimentally that a nanoscale area of plasmon-enhanced electron emission can be motioned by changing the polarization of an exciting optical beam of 800 nm wavelength. Finite-difference calculations are presented to support the experiments and to show that the plasmon-enhanced electric field distribution of the antenna can be motioned precisely and predictively.

  20. Los Angeles megacity: a high-resolution land-atmosphere modelling system for urban CO2 emissions

    Science.gov (United States)

    Feng, Sha; Lauvaux, Thomas; Newman, Sally; Rao, Preeti; Ahmadov, Ravan; Deng, Aijun; Díaz-Isaac, Liza I.; Duren, Riley M.; Fischer, Marc L.; Gerbig, Christoph; Gurney, Kevin R.; Huang, Jianhua; Jeong, Seongeun; Li, Zhijin; Miller, Charles E.; O'Keeffe, Darragh; Patarasuk, Risa; Sander, Stanley P.; Song, Yang; Wong, Kam W.; Yung, Yuk L.

    2016-07-01

    Megacities are major sources of anthropogenic fossil fuel CO2 (FFCO2) emissions. The spatial extents of these large urban systems cover areas of 10 000 km2 or more with complex topography and changing landscapes. We present a high-resolution land-atmosphere modelling system for urban CO2 emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO2 emission product, Hestia-LA, to simulate atmospheric CO2 concentrations across the LA megacity at spatial resolutions as fine as ˜ 1 km. We evaluated multiple WRF configurations, selecting one that minimized errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May-June 2010). Our results show no significant difference between moderate-resolution (4 km) and high-resolution (1.3 km) simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution) and Hestia-LA (1.3 km resolution) fossil fuel CO2 emission products to evaluate the impact of the spatial resolution of the CO2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO2 concentrations. We find that high spatial resolution in the fossil fuel CO2 emissions is more important than in the atmospheric model to capture CO2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO2 fields reflect the coverage of individual measurement sites when a

  1. Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, J.V. Jr.; Simonen, C.A.; Burk, K.W.

    1994-02-01

    The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses that individuals may have received from operations at the Hanford Site since 1944. This report deals specifically with the atmospheric transport model, Regional Atmospheric Transport Code for Hanford Emission Tracking (RATCHET). RATCHET is a major rework of the MESOILT2 model used in the first phase of the HEDR Project; only the bookkeeping framework escaped major changes. Changes to the code include (1) significant changes in the representation of atmospheric processes and (2) incorporation of Monte Carlo methods for representing uncertainty in input data, model parameters, and coefficients. To a large extent, the revisions to the model are based on recommendations of a peer working group that met in March 1991. Technical bases for other portions of the atmospheric transport model are addressed in two other documents. This report has three major sections: a description of the model, a user`s guide, and a programmer`s guide. These sections discuss RATCHET from three different perspectives. The first provides a technical description of the code with emphasis on details such as the representation of the model domain, the data required by the model, and the equations used to make the model calculations. The technical description is followed by a user`s guide to the model with emphasis on running the code. The user`s guide contains information about the model input and output. The third section is a programmer`s guide to the code. It discusses the hardware and software required to run the code. The programmer`s guide also discusses program structure and each of the program elements.

  2. Percolating plasmonic networks for light emission control

    OpenAIRE

    Gaio, Michele; Castro-Lopez, Marta; Renger, Jan; Hulst, Niek van; Sapienza, Riccardo

    2014-01-01

    Optical nanoantennas have revolutionised the way we manipulate single photons emitted by individual light sources in a nanostructured photonic environment. Complex plasmonic architectures allow for multiscale light control by shortening or stretching the light wavelength for a fixed operating frequency, meeting the size of the emitter and that of propagating modes. Here, we study self-assembled semi-continuous gold films and lithographic gold networks characterised by large local density of o...

  3. Future atmospheric abundances and climate forcings from scenarios of global and regional hydrofluorocarbon (HFC) emissions

    Science.gov (United States)

    Velders, Guus J. M.; Fahey, David W.; Daniel, John S.; Andersen, Stephen O.; McFarland, Mack

    2015-12-01

    Hydrofluorocarbons (HFCs) are manufactured for use as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. While HFCs do not deplete ozone, many are potent greenhouse gases that contribute to climate change. Here, new global scenarios show that baseline emissions of HFCs could reach 4.0-5.3 GtCO2-eq yr-1 in 2050. The new baseline (or business-as-usual) scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. The scenarios rely on detailed data reported by countries to the United Nations; projections of gross domestic product and population; and recent observations of HFC atmospheric abundances. In the baseline scenarios, by 2050 China (31%), India and the rest of Asia (23%), the Middle East and northern Africa (11%), and the USA (10%) are the principal source regions for global HFC emissions; and refrigeration (40-58%) and stationary air conditioning (21-40%) are the major use sectors. The corresponding radiative forcing could reach 0.22-0.25 W m-2 in 2050, which would be 12-24% of the increase from business-as-usual CO2 emissions from 2015 to 2050. National regulations to limit HFC use have already been adopted in the European Union, Japan and USA, and proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries.

  4. Identification and characterization of the atmospheric emission of polychlorinated naphthalenes from electric arc furnaces.

    Science.gov (United States)

    Liu, Guorui; Zheng, Minghui; Du, Bing; Nie, Zhiqiang; Zhang, Bing; Hu, Jicheng; Xiao, Ke

    2012-09-01

    Electric arc furnaces (EAF) are well recognized as significant sources of dioxins. EAFs have also been speculated to be sources of polychlorinated naphthalenes (PCNs) due to the close correlation between dioxin and PCN formation. However, assessment on PCN emissions from EAFs has not been carried out. The primary aim of this preliminary study is to identify and characterize the atmospheric emission of PCNs from EAFs. In this preliminary study, stack gas samples from two typical EAFs with different scales (EAF-1, 160 t batch(-1); and EAF-2, 60 t batch(-1)) were collected by automatic isokinetic sampling technique, and PCN congeners in samples were analyzed by isotope dilution high-resolution gas chromatography combined with high-resolution mass spectrometry method. Emission concentrations of PCNs were 458 and 1,099 ng m(-3) for EAF-1 and EAF-2, respectively. The emission factors of PCNs to air were 21.6 and 30.1 ng toxic equivalent t(-1) for EAF-1 and EAF-2, respectively, which suggested that EAF is an important source of PCN release. With regard to the characteristics of PCNs from EAFs, lower chlorinated homologues were dominant. The PCN congeners comprised of CN27/30, CN52/60, CN66/67, and CN73 were the most abundant congeners for tetra-, penta-, hexa-, and hepta-chlorinated homologues, respectively. EAFs were identified to be an important PCN source, and the obtained data are useful for developing a PCN inventory. The congener profiles of PCNs presented here might provide helpful information for identifying the specific sources of PCNs emitted from EAFs.

  5. Controlling formaldehyde emissions with boiler ash.

    Science.gov (United States)

    Cowan, Jennifer; Abu-Daabes, Malyuba; Banerjee, Sujit

    2005-07-01

    Fluidized wood ash reduces formaldehyde in air from about 20 to formaldehyde reduction increases with increasing moisture content of the ash. Sorption of formaldehyde to ash can be substantially accounted for by partitioning to the water contained in the ash followed by rate-controlling binding to the ash solids. Adsorption occurs at temperatures of up to 165 degrees C; oxidation predominates thereafter. It is proposed that formaldehyde could be stripped from an air stream in a fluidized bed containing ash, which could then be returned to a boiler to incinerate the formaldehyde.

  6. Energy scenarios for Switzerland and emission control, estimated with a normative model

    International Nuclear Information System (INIS)

    The reported work presents results of the IEA-ETSAP project (International Energy Agency - Energy Technology Systems Analysis Project) concerning the interrelations among energy use, emissions to the atmosphere and the cost of emission control. The energy simulation model SMEDE, which has been developed at PSI and applies the engineering simulation (bottom up) approach, and the IEA optimization model MARKAL (MARKet ALlocation) have been used to analyse the energy demand and supply system of Switzerland. The purpose of this analysis is to identify technical options and their cost for reducing the energy dependent atmospheric emissions in Switzerland to the levels of the 'clean air concept'. The study addresses also the question of the feasibility and the economic implications of reducing the CO2 emissions to the levels recommended by the Toronto conference. The implications of a stringent 'clean air concept' and these of the Toronto recommendations have been analysed under different nuclear supply options i.e. an unconstrained nuclear supply case (reference), a nuclear status-quo (moratorium) and under the conditions of a nuclear phase-out programme by the year 2025. The main conclusions of this analysis indicate that the emissions of sulfur dioxide and nitrogen oxide could be reduced back to the levels of 1950 respectively 1960, by the introduction of emission control technologies which go above the present performance limits defined by the 'clean air ordinance' (LRV). A probable time horizon to satisfy the NOx constraints is the year 2000 and not 1995. Organizational measures necessary to improve the air quality in cities are complementary to the measures proposed in this analysis. (author) figs., tabs., 18 refs

  7. The global SF6 source inferred from long-term high precision atmospheric measurements and its comparison with emission inventories

    Directory of Open Access Journals (Sweden)

    R. Weller

    2010-03-01

    Full Text Available Emissions of sulphur hexafluoride (SF6, one of the strongest greenhouse gases on a per molecule basis, are targeted to be collectively reduced under the Kyoto Protocol. Because of its long atmospheric lifetime (estimated as 800 to 3200 years, the accumulation of SF6 in the atmosphere is a direct measure of its global emissions. Examination of our extended data set of globally distributed high-precision SF6 observations shows an increase in SF6 abundance from near zero in the 1970s to a global mean of 6.7 ppt by the end of 2008. In-depth evaluation of our long-term data records shows that the global source of SF6 decreased after 1995, most likely due to SF6 emission reductions in industrialised countries, but increased again after 1998. By subtracting those emissions reported by Annex I countries to the United Nations Framework Convention of Climatic Change (UNFCCC from our observation-inferred SF6 source leaves a surprisingly large gap of more than 70–80% of non-reported SF6 emissions in the last decade. This suggests a strong under-estimation of emissions in Annex I countries and underlines the urgent need for independent atmospheric verification of greenhouse gases emissions accounting.

  8. Controlling spontaneous emission of light by photonic crystals

    DEFF Research Database (Denmark)

    Lodahl, Peter

    2005-01-01

    Photonic bandgap crystals were proposed almost two decades ago as a unique tool for controlling propagation and emission of light. Since then the research field of photonic crystals has exploded and many beautiful demonstrations of the use of photonic crystals and fibers for molding light...... propagation have appeared that hold great promises for integrated optics. These major achievements solidly demonstrate the ability to control propagation of light. In contrast, an experimental demonstration of the use of photonic crystals for timing the emission of light has so far lacked. In a recent...... publication in Nature, we have demonstrated experimentally that both the direction and time of spontaneous emission can be controlled, thereby confirming the original proposal by Eli Yablonovich that founded the field of photonic crystals. We believe that this work opens new opportunities for solid...

  9. Atmosphere-based nation-wide emission estimates of hydrofluorocarbons and hydrochlorofluorocarbons from the U.S

    Science.gov (United States)

    Hu, L.; Montzka, S. A.; Miller, J. B.; Andrews, A. E.; Miller, B. R.; Thoning, K. W.; Sweeney, C.; Chen, H.; Bruhwiler, L.; Masarie, K.; Miller, S. M.; Fischer, M. L.; Saikawa, E.; Elkins, J. W.; Tans, P. P.

    2013-12-01

    Limiting the warming influence induced by greenhouse gases (GHGs) ultimately requires reductions in emissions. To evaluate emission magnitudes and their changes over time, we recommend verifying self-reported emission inventories with independent, atmosphere-based, 'top-down' estimates. Hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are potent GHGs with global warming potentials up to thousands of times larger than CO2 over a 100-year time horizon. Reductions in HCFC production and consumption were required by the Montreal Protocol in developed countries beginning in 2004. However, it is uncertain whether emissions of these gases are declining within the US because emissions are not linearly related to production or consumption due to the existence of substantial 'banks' (stores of in-use chemicals that have not yet escaped to the atmosphere). HFCs are replacements for CFCs and HCFCs. Without regulation, CO2 equivalent emissions of HFCs could become substantial in the future relative to CO2. In this study, we estimated emissions of HCFC-22 and HFC-134a within the US from 2008 - 2012 using a Bayesian approach of a regional inverse model with atmospheric observations from 8 tall-tower sites, 5 surface flask sites and 19 aircraft sites. We used a maximum likelihood estimation to estimate model-data mismatch errors, prior flux uncertainty, and temporal and spatial correlations in flux deviations between prior and posterior fluxes. We optimized our model design and tested our model performance by conducting synthetic data experiments. With this optimized design and boundary mixing ratios calculated with three different approaches, we derived national emissions of HCFC-22 and HFC-134a. This study provides the first multi-year atmosphere-based national emission estimates of HCFC-22 and HFC-134a, derived from multiple sites distributed across the US.

  10. Atmospheric and children's blood lead as indicators of vehicular traffic and other emission sources in Mumbai, India

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, R.M.; Raghunath, R.; Vinod Kumar, A.; Sastry, V.N.; Sadasivan, S. [Environmental Assessment Division, Bhabha Atomic Research Centre, 400 085 Mumbai (India)

    2001-02-21

    Average concentration of Pb in atmospheric air particulates in different suburbs of Mumbai was studied for almost a decade and its spatial and temporal profiles are discussed in relation to emission sources. In general the concentration of Pb in all the residential suburban atmosphere is well below the Central Pollution Control Board (CPCB, 1994) prescribed limit of 1.5 {mu}g m{sup -3} barring a few exceptions for some residential/industrial sites, such as those of Thane and Kurla scrap yards. The correlation between blood lead of children and air lead reveals that the blood Pb level in children could increase by 3.6 {mu}g dl{sup -1} for an incremental rise of 1.0 {mu}g Pb m{sup -3} of air. The temporal profile of air Pb values indicates a decreasing trend in residential suburbs (Khar: 1984, 0.39 {mu}g m{sup -3}; 1996, 0.17 {mu}g m{sup -3}) as well as in suburban residential areas with low traffic (Goregaon: 1984, 0.53 {mu}g m{sup -3}; 1996, 0.30 {mu}g m{sup -3})

  11. External control of planetary radio emission

    Science.gov (United States)

    Rucker, H. O.; Desch, M. D.

    1983-01-01

    Recent studies using data from Voyagers 1 and 2 to correlate variations in the Saturn kilometric radiation (SKR) with changes in solar-wind properties are summarized and illustrated with graphs. Best SKR correlations have been obtained with the solar-wind ram pressure and the related kinetic energy flux. It is pointed out that the related phenomenon on earth, the auroral kilometric radiation, occurs mainly in the nightside auroral region (as opposed to the dayside cleft region for SKR) and is best correlated with solar-wind velocity and inverted-V electron-precipitation events, implying a different stimulation process. The evidence for solar-wind control of the non-Io-related decametric radiation of Jupiter is also reviewed.

  12. Towards an Integrated Assessment Model for Tropospheric Ozone-Emission Inventories, Scenarios and Emission-control Options

    OpenAIRE

    Olsthoorn, X.

    1994-01-01

    IIASA intends to extend its RAINS model for addressing the issue of transboundary ozone air pollution. This requires the development of a VOC-emissions module, VOCs being precursors in ozone formation. The module should contain a Europe-wide emission inventory, a submodule for developing emission scenarios and a database of measures for VOC-emission control, including data about control effectiveness and control costs. It is recommended to use the forthcoming CORINAIR90 inventory for construc...

  13. Reduced VOC emissions from birch sawdust dried in a steam drier at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Granstrom, K.M. [Karlstad Univ., Karlstad (Sweden). Dept. of Environmental and Energy Systems, Div. of Engineering Sciences, Physics and Mathematics

    2003-07-01

    A study was conducted to determine the quantity and composition of volatile organic compounds (VOC) emitted from birch sawdust when it is dried in a steam dryer at atmospheric pressure. Sawdust is commonly dried for production of wood pellets and particle board. VOCs, which are emitted during the drying process, contribute to the formation of ground level ozone and other hazardous photochemical oxidants. The chemical composition of VOCs emitted from drying softwood is different from that emitted during the drying of hardwoods such as birch. The dryer used in this study was a pilot scale spouted bed in continuous operation. Sawdust was dried to different moisture contents. Two drying medium temperatures (170 degrees C and 200 degrees C) were applied. The results were then compared to the emissions from softwoods dried under similar conditions.

  14. A template of atmospheric O2 circularly polarized emission for CMB experiments

    CERN Document Server

    Spinelli, Sebastiano; Tartari, Andrea; Zannoni, Mario; Gervasi, Massimo

    2011-01-01

    We compute the circularly polarized signal from atmospheric molecular oxygen. Polarization of O2 rotational lines is caused by Zeeman effect in the Earth magnetic field. We evaluate the circularly polarized emission for various sites suitable for CMB measurements: South Pole and Dome C (Antarctica), Atacama (Chile) and Testa Grigia (Italy). An analysis of the polarized signal is presented and discussed in the framework of future CMB polarization experiments. We find a typical circularly polarized signal (V Stokes parameter) of ~ 50 - 300 {\\mu}K at 90 GHz looking at the zenith. Among the other sites Atacama shows the lower polarized signal at the zenith. We present maps of this signal for the various sites and show typical elevation and azimuth scans. We find that Dome C presents the lowest gradient in polarized temperature: ~ 0.3 {\\mu}K/\\circ at 90 GHz. We also study the frequency bands of observation: around {\

  15. Plasmonic phase-gradient metasurface for spontaneous emission control

    Science.gov (United States)

    Langguth, L.; Schokker, A. H.; Guo, K.; Koenderink, A. F.

    2015-11-01

    We combine the concept of phase-gradient metasurfaces with fluorescence directionality control of an ensemble of incoherent emitters. We design a periodic metasurface to control the scattering amplitude of the lattice in momentum space. The lattice is embedded in a waveguiding layer doped with organic fluorophores. In contrast to the usual symmetric directionality that plasmonic lattices impart on emission, we find that the phase gradient translates into asymmetric directional emission into the far field, determined by scattering on a subset of the reciprocal lattice vectors. The measured asymmetry is well explained by analytical modeling.

  16. Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2012-08-01

    Full Text Available The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B, and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE, presented in a companion paper, and with the recent past (year 2000. Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario.

    As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000.

    Radiative Forcing (RF calculations show that the net effect of AIR, SHIP and ROAD combined will change from a~marginal cooling of −0.38 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 8.9 (B1 or −31 ± 20 mW m−2 (A1B in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −20 ± 5.4 mW m−2 in 2000 to

  17. Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

    Directory of Open Access Journals (Sweden)

    Ø. Hodnebrog

    2012-12-01

    Full Text Available The future impact of traffic emissions on atmospheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an ensemble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possible high emission scenario (A1B, and with emissions from each transport sector reduced by 5% to estimate sensitivities. Our results are compared with optimistic future emission scenarios (B1 and B1 ACARE, presented in a companion paper, and with the recent past (year 2000. Present-day activity indicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario.

    As a response to expected changes in emissions, AIR and SHIP will have increased impacts on atmospheric O3 and OH in the future while the impact of ROAD traffic will decrease substantially as a result of technological improvements. In 2050, maximum aircraft-induced O3 occurs near 80° N in the UTLS region and could reach 9 ppbv in the zonal mean during summer. Emissions from ship traffic have their largest O3 impact in the maritime boundary layer with a maximum of 6 ppbv over the North Atlantic Ocean during summer in 2050. The O3 impact of road traffic emissions in the lower troposphere peaks at 3 ppbv over the Arabian Peninsula, much lower than the impact in 2000.

    Radiative forcing (RF calculations show that the net effect of AIR, SHIP and ROAD combined will change from a marginal cooling of −0.44 ± 13 mW m−2 in 2000 to a relatively strong cooling of −32 ± 9.3 (B1 or −32 ± 18 mW m−2 (A1B in 2050, when taking into account RF due to changes in O3, CH4 and CH4-induced O3. This is caused both by the enhanced negative net RF from SHIP, which will change from −19 ± 5.3 mW m−2 in 2000 to

  18. Influence of atmospheric convection on the long and short-range transport of Xe133 emissions.

    Science.gov (United States)

    Kusmierczyk-Michulec, Jolanta; Krysta, Monika; Gheddou, Abdelhakim; Nikkinen, Mika

    2014-05-01

    The International Monitoring System (IMS) developed by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is a global system of monitoring stations, using four complementary technologies: seismic, hydroacoustic, infrasound and radionuclide. Data from all stations, belonging to IMS, are collected and transmitted to the International Data Centre (IDC) in Vienna, Austria. The radionuclide network comprises 79 stations, of which more than 60 are certified. The aim of radionuclide stations is a global monitoring of radioactive aerosols and radioactive noble gases supported by the atmospheric transport modelling (ATM). The ATM system is based on the Lagrangian Particle Dispersion Model, FLEXPART, designed for calculating the long-range and mesoscale dispersion of air pollution from point sources. In the operational configuration only the transport of the passive tracer is simulated. The question arises whether including other atmospheric processes, like convection, will improve results. To answer this question a series of forward simulations was conducted, assuming the maximum transport of 14 days. Each time 2 runs were performed: one with convection and one without convection. The release point was at the ANSTO facility in Australia. Due to the fact that CTBTO has recently received a noble gas emission inventory from the ANSTO facility we had a chance to do more accurate simulations. Studies have been performed to link Xe133 emissions with detections at the IMS stations supported by the ATM. The geographical localization to some extend justifies the assumption that the only source of Xe133 observed at the neighbouring stations, e.g. AUX04, AUX09 and NZX46, comes from the ANSTO facility. In simulations the analysed wind data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) were used with the spatial resolution of 0.5 degree. The results of quantitative and qualitative comparison will be presented.

  19. The space and time impacts on U.S. regional atmospheric CO2 concentrations from a high resolution fossil fuel CO2 emissions inventory

    OpenAIRE

    Katherine D. Corbin; Denning, A Scott; Gurney, Kevin R

    2011-01-01

    To improve fossil fuel CO2 emissions estimates, high spatial and temporal resolution inventories are replacing coarse resolution, annual-mean estimates distributed by population density. Because altering the emissions changes a key boundary condition to inverse-estimated CO2 fluxes, it is essential to analyse the atmospheric impacts of redistributing anthropogenic emissions. Using a coupled ecosystem–atmosphere model, we compare 2004 atmospheric CO2 concentrations resulting from coarse and hi...

  20. Impact of various emission control schemes on air quality using WRF-Chem during APEC China 2014

    Science.gov (United States)

    Guo, Jianping; He, Jing; Liu, Hongli; Miao, Yucong; Liu, Huan; Zhai, Panmao

    2016-09-01

    Emission control measures have been implemented to make air quality good enough for Asia-Pacific Economic Cooperation (APEC) China 2014, which provides us with an ideal test-bed to determine how these measures affect air quality in Beijing and surrounding areas. Based on hourly observations at eight monitoring sites of Beijing, the concentrations of other primary atmospheric pollutants during APEC were found to have significantly lower magnitudes than those before APEC, with the exception of a higher O3 concentration. Overall, WRF/Chem reproduced the observed time series of PM2.5, PM10, NO2, CO, and O3 notably well. To investigate the impact of emission control measures on air quality on both local and regional scales, four emission control schemes were developed according to the locations where emission reduction had taken place; the corresponding simulations were subsequently run separately. Scheme S2 (emission control implemented in Beijing) resulted in reductions of 22%, 24%, 10% and 22% for the concentrations of PM2.5, PM10, NO2 and CO, respectively, compared with 14%, 14%, 8%, and 13% for scheme S3 (emission controls implemented from outside of Beijing). This finding indicates that the local emission reduction in Beijing contributes more to the improved air quality in Beijing during APEC China 2014 than does the emission reduction from outside of Beijing. In terms of the impact on the regional scale, the real emission control scheme led to significant reduction of PM2.5 throughout the whole domain. Although the regional impact cannot be completely ignored, both emission reduction measures implemented in Beijing and those implemented outside of Beijing favor greater reduction in PM2.5 in the domains where measurements are presumably taken, as compared with other domains. Therefore, to improve the air quality in Beijing, more coordinated efforts should be made, particularly in the aspect of more stringent reduction and control strategies on pollutant emission

  1. The controls of methane emission from an Indian mangrove

    Science.gov (United States)

    Purvaja, R.; Ramesh, R.; Frenzel, P.

    2003-04-01

    Mangroves have been rated for a long time as a minor methane source, but recent reports have shown that polluted mangroves may emit substantial amounts of methane. In an Indian mangrove dominated by Avicennia marina we measured annual methane emission rates of 10 g methane/year, comparable to those from Northern wetlands. Methane emission from a freshwater-influenced area was higher, but lower from a stunted mangrove growing on a hypersaline soil, respectively. Methane emission was mediated by the pneumatophores of Avicennia. This was consistent with the methane concentration in the aerenchyma that decreased on average from 350 ppmv in the cable roots to 10 ppmv in the emergent part of the pneumatophores. The number of pneumatophores varied seasonally. During the monsoon floods less pneumatophores emerged from the water, reducing methane fluxes largely. Hence, CH4 emission was controlled via the pneumatophores by the water level.

  2. Mercury emissions to the atmosphere from anthropogenic sources in Europe in 2000 and their scenarios until 2020.

    Science.gov (United States)

    Pacyna, Elisabeth G; Pacyna, Jozef M; Fudala, Janina; Strzelecka-Jastrzab, Ewa; Hlawiczka, Stanislaw; Panasiuk, Damian

    2006-10-15

    The paper reviews the current state of knowledge regarding European emissions of mercury and presents estimates of European emissions of mercury to the atmosphere from anthropogenic sources for the year 2000. This information was then used as a basis for Hg emission scenario development until the year 2020. Combustion of coal in power plants and residential heat furnaces generates about half of the European emissions being 239 tonnes. The coal combustion is followed by the production of caustic soda with the use of the Hg cell process (17%). Major points of mercury emission generation in the mercury cell process include: by-product hydrogen stream, end box ventilation air, and cell room ventilation air. This technology is now being changed to other caustic soda production technologies and further reduction of Hg emissions is expected in this connection. The third category on the list of the largest Hg emitters in Europe is cement production (about 13%). The largest emissions were estimated for Russia (the European part of the country), contributing with about 27% to the European emissions, followed by Poland, Germany, Spain, Ukraine, France, Italy and the United Kingdom. Most of these countries use coal as a major source of energy in order to meet the electricity and heat demands. In general, countries in the Central and Eastern Europe generated the main part of the European emissions in 2000. Emission reductions between 20% and 80% of the 2000 emission amounts can be obtained by the year 2020, as estimated by various scenarios. PMID:16887169

  3. High-resolution atmospheric inversion of urban CO2 emissions during the dormant season of the Indianapolis Flux Experiment (INFLUX)

    Science.gov (United States)

    Lauvaux, Thomas; Miles, Natasha L.; Deng, Aijun; Richardson, Scott J.; Cambaliza, Maria O.; Davis, Kenneth J.; Gaudet, Brian; Gurney, Kevin R.; Huang, Jianhua; O'Keefe, Darragh; Song, Yang; Karion, Anna; Oda, Tomohiro; Patarasuk, Risa; Razlivanov, Igor; Sarmiento, Daniel; Shepson, Paul; Sweeney, Colm; Turnbull, Jocelyn; Wu, Kai

    2016-05-01

    Based on a uniquely dense network of surface towers measuring continuously the atmospheric concentrations of greenhouse gases (GHGs), we developed the first comprehensive monitoring systems of CO2 emissions at high resolution over the city of Indianapolis. The urban inversion evaluated over the 2012-2013 dormant season showed a statistically significant increase of about 20% (from 4.5 to 5.7 MtC ± 0.23 MtC) compared to the Hestia CO2 emission estimate, a state-of-the-art building-level emission product. Spatial structures in prior emission errors, mostly undetermined, appeared to affect the spatial pattern in the inverse solution and the total carbon budget over the entire area by up to 15%, while the inverse solution remains fairly insensitive to the CO2 boundary inflow and to the different prior emissions (i.e., ODIAC). Preceding the surface emission optimization, we improved the atmospheric simulations using a meteorological data assimilation system also informing our Bayesian inversion system through updated observations error variances. Finally, we estimated the uncertainties associated with undetermined parameters using an ensemble of inversions. The total CO2 emissions based on the ensemble mean and quartiles (5.26-5.91 MtC) were statistically different compared to the prior total emissions (4.1 to 4.5 MtC). Considering the relatively small sensitivity to the different parameters, we conclude that atmospheric inversions are potentially able to constrain the carbon budget of the city, assuming sufficient data to measure the inflow of GHG over the city, but additional information on prior emission error structures are required to determine the spatial structures of urban emissions at high resolution.

  4. Atmospheric observation-based global SF6 emissions - comparison of top-down and bottom-up estimates

    OpenAIRE

    Levin, Ingeborg; Naegler, Tobias; Heinz, Renate; Osusko, Daniel; Cuevas, Emilio; Engel, Andreas; Ilmberger, Johann; Langenfelds, Ray L.; Neininger, Bruno; Rohden, Christoph von; Steele, L. Paul; Weller, Rolf; Worthy, Douglas E. W; Zimov, Sergej A.

    2010-01-01

    Emissions of sulphur hexafluoride (SF6), one of the strongest greenhouse gases on a per molecule basis, are targeted to be collectively reduced under the Kyoto Protocol. Because of its long atmospheric lifetime (estimated as 800 to 3200 years), the accumulation of SF6 in the atmosphere is a direct measure of its global emissions. Examination of our extended data set of globally distributed high-precision SF6 observations shows an increase in SF6 abundance from near zero in the 1970s to a glob...

  5. Control of blue mold of apple by combining controlled atmosphere, antagonist mixtures and sodium bicarbonate

    Science.gov (United States)

    'Golden Delicious' apples were wound-inoculated with Penicillium expansum, treated with various combinations of sodium bicarbonate and two antagonists, and stored in air or controlled atmosphere (1.4% O2, 3% CO2). The fruit were stored for 2 or 4 months at 1°C. The antagonists survived and their p...

  6. Deciphering the Atmospheric Composition of WASP-12b: A Comprehensive Analysis of its Dayside Emission

    CERN Document Server

    Stevenson, Kevin B; Madhusudhan, Nikku; Harrington, Joseph

    2014-01-01

    WASP-12b was the first planet reported to have a carbon-to-oxygen ratio (C/O) greater than one in its dayside atmosphere. However, recent work to further characterize its atmosphere and confirm its composition has led to incompatible measurements and divergent conclusions. Additionally, the recent discovery of stellar binary companions ~1" from WASP-12 further complicates the analyses and subsequent interpretations. We present a uniform analysis of all available Hubble and Spitzer Space Telescope secondary-eclipse data, including previously-unpublished Spitzer measurements at 3.6 and 4.5 microns. The primary controversy in the literature has centered on the value and interpretation of the eclipse depth at 4.5 microns. Our new measurements and analyses confirm the shallow eclipse depth in this channel, as first reported by Campo and collaborators and used by Madhusudhan and collaborators to infer a carbon-rich composition. To explain WASP-12b's observed dayside emission spectrum, we implemented several recent ...

  7. Emission of carbon. A most important component for greenhouse effect in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Milaev, V.B.; Kopp, I.Z.; Yasenski, A.N. [Scientific Research Inst. of Atmospheric Air Protection, St. Petersburg (Russian Federation)

    1995-12-31

    Greenhouse effect is most often defined as the probabilities of atmospheric air quasiequilibrium temperature increase as a result of air pollution due to emission of anthropogenic gaseous substances which are usually called `greenhouse gases`. Among greenhouse gases are primarily considered several gaseous substances which contain carbon atoms: carbon oxide, carbon dioxide and methane (CO, CO{sub 2} and CH{sub 4}), and chlorinated and fluorinated hydrocarbons (freons) spectra of which are transparent to solar radiation, but absorb and reradiate longwave radiation causing disturbance of quasistationary thermal regieme of the atmosphere. Qualitative estimates of the income and relative roles of different substances in occurrence of greenhouse effect differ considerable. At the modern state of knowledge the problem of greenhouse effect and greenhouse gases is considered in several aspects. The most widespread and investigated is climatic or meteorological aspect, it is discussed in a number of international works. Rather pressing is thermal physics aspect of the problem of estimating greenhouse effect, which consists in correct construction of a calculation model and usage of the most representative experimental data, since analytical methods require many assumptions, introduction of which may lead to results which differ very much. Bearing these uncertainties in mind the UNEP/WMO/ICSU conference has included into the number of the most urgent tasks in the study of greenhouse effect, the problem of determining the priority of factors which cause greenhouse effect, which in its turn predetermines the necessity to substantiate the methods of selection and criterion of comparative evaluation of such factors. (author)

  8. Mars Global Surveyor Thermal Emission Spectrometer (TES) Observations: Atmospheric Temperatures During Aerobraking and Science Phasing

    Science.gov (United States)

    Conrath, Barney J.; Pearl, John C.; Smith, Michael D.; Maguire, William C.; Christensen, Philip R.; Dason, Shymala; Kaelberer, Monte S.

    1999-01-01

    Between September 1997, when the Mars Global Surveyor spacecraft arrived at Mars, and September 1998 when the final aerobraking phase of the mission began, the Thermal Emission Spectrometer (TES) has acquired an extensive data set spanning approximately half of a Martian year. Nadir-viewing spectral measurements from this data set within the 15-micrometers CO2 absorption band are inverted to obtain atmospheric temperature profiles from the surface up to about the 0.1 mbar level. The computational procedure used to retrieve the temperatures is presented. Mean meridional cross sections of thermal structure are calculated for periods of time near northern hemisphere fall equinox, winter solstice, and spring equinox, as well as for a time interval immediately following the onset of the Noachis Terra dust storm. Gradient thermal wind cross sections are calculated from the thermal structure. Regions of possible wave activity are identified using cross sections of rms temperature deviations from the mean. Results from both near-equinox periods show some hemispheric asymmetry with peak eastward thermal winds in the north about twice the magnitude of those in the south. The results near solstice show an intense circumpolar vortex at high northern latitudes and waves associated with the vortex jet core. Warming of the atmosphere aloft at mid-northern latitudes suggests the presence of a strong cross-equatorial Hadley circulation. Although the Noachis dust storm did not become global in scale, strong perturbations to the atmospheric structure are found, including an enhanced temperature maximum aloft at high northern latitudes resulting from intensification of the Hadley circulation. TES results for the various seasonal conditions are compared with published results from Mars general circulation models, and generally good qualitative agreement is found.

  9. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    OpenAIRE

    Petzold, A.; Hasselbach, J.; P. Lauer; Baumann, R.; Franke, K.; Gurk, C.; H. Schlager; Weingartner, E.

    2008-01-01

    Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B&W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transform...

  10. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    OpenAIRE

    Petzold, A.; Hasselbach, J.; P. Lauer; Baumann, R.; Franke, K.; Gurk, C.; H. Schlager; Weingartner, E.

    2007-01-01

    Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B{&}W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transfo...

  11. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    OpenAIRE

    Petzold, A.; Hasselbach, J.; P. Lauer; Baumann, R.; Franke, K.; Gurk, C.; H. Schlager; Weingartner, E.

    2007-01-01

    Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B&W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aer...

  12. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    OpenAIRE

    Petzold, Andreas; Hasselbach, Jan; Lauer, Peter; Baumann, Robert; Franke, Klaus; Gurk, Christian; Schlager, Hans; Weingartner, Ernest

    2008-01-01

    International audience Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B&W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airb...

  13. Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

    OpenAIRE

    Petzold, A.; Hasselbach, J.; P. Lauer; Baumann, R.; Franke, K.; Gurk, C.; H. Schlager; Weingartner, E.

    2007-01-01

    International audience Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B{&}W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by ai...

  14. Atmospheric transport modelling of time resolved 133Xe emissions from the isotope production facility ANSTO, Australia.

    Science.gov (United States)

    Schöppner, M; Plastino, W; Hermanspahn, N; Hoffmann, E; Kalinowski, M; Orr, B; Tinker, R

    2013-12-01

    The verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT) relies amongst other things on the continuous and worldwide monitoring of radioxenon. The characterization of the existing and legitimate background, which is produced mainly by nuclear power plants and isotope production facilities, is of high interest to improve the capabilities of the monitoring network. However, the emissions from legitimate sources can usually only be estimated. For this paper historic source terms of (133)Xe emissions from the isotope production facility at ANSTO, Sydney, Australia, have been made available in a daily resolution. Based on these high resolution data, different source term sets with weekly, monthly and yearly time resolution have been compiled. These different sets are then applied together with atmospheric transport modelling (ATM) to predict the concentration time series at two radioxenon monitoring stations. The results are compared with each other in order to examine the improvement of the prediction capability depending on the used time resolution of the most dominant source term in the region.

  15. The importance of vehicle emissions as a source of atmospheric ammonia in the megacity of Shanghai

    Directory of Open Access Journals (Sweden)

    Y. H. Chang

    2015-12-01

    Full Text Available Agricultural activities are a major source contributing to NH3 emissions in Shanghai and most other regions of China; however, there is a long-standing and ongoing controversy regarding the contributions of vehicle-emitted NH3 to the urban atmosphere. From April 2014 to April 2015, we conducted measurements of a wide range of gases (including NH3 and the chemical properties of PM2.5 at hourly resolution at a Shanghai urban supersite. This large dataset shows NH3 pollution events, lasting several hours with concentrations four times the annual average of 5.3 μg m-3, caused by the burning of crop residues in spring. There are also generally higher NH3 concentrations (mean ± 1σ in summer (7.3 ± 4.9 μg m-3; n = 2181 because of intensive emissions from temperature-dependent agricultural sources. However, the NH3 concentration in summer was only an average of 2.4 μg m-3 or 41 % higher than the average NH3 concentration of other seasons. Furthermore, the NH3 concentration in winter (5.0 ± 3.7 μg m-3; n = 2113 was similar to that in spring (5.1 ± 3.8 μg m-3; n = 2204 but slightly higher, on average, than that in autumn (4.5 ± 2.3 μg m-3; n = 1949. Moreover, other meteorological parameters like planetary boundary layer height and relative humidity were not major factors affecting seasonal NH3 concentrations. These findings suggest that there may be some climate-independent NH3 sources present in the Shanghai urban area. Independent of season, the concentrations of both NH3 and CO present a marked bimodal diurnal profile, with maxima in the morning and the evening. A spatial analysis suggests that elevated concentrations of NH3 are often associated with transport from regions west-northwest and east-southeast of the city, areas with dense road systems. The spatial origin of NH3 and the diurnal concentration profile together suggest the importance of vehicle-derived NH3 associated with daily commuting in the urban environment. To further

  16. Atmospheric mercury emissions from mine wastes and surrounding geologically enriched terrains

    Science.gov (United States)

    Gustin, M.S.; Coolbaugh, M.F.; Engle, M.A.; Fitzgerald, B.C.; Keislar, R.E.; Lindberg, S.E.; Nacht, D.M.; Quashnick, J.; Rytuba, J.J.; Sladek, C.; Zhang, H.; Zehner, R.E.

    2003-01-01

    Waste rock and ore associated with Hg, precious and base metal mining, and their surrounding host rocks are typically enriched in mercury relative to natural background concentrations (soil:air interface, and photo reduction of mercury containing phases. To determine the need for and effectiveness of regulatory controls on short-lived anthropogenic point sources the contribution of mercury from geologic non-point sources to the atmospheric mercury pool needs to be quantified. The atmospheric mercury contribution from small areas of mining disturbance with relatively high mercury concentrations are, in general, less than that from surrounding large areas of low levels of mercury enrichment. In the arid to semi-arid west-ern United States volatilization is the primary means by which mercury is released from enriched sites.

  17. Switching regulator emission control circuit for ion sources

    Science.gov (United States)

    Clay, F. P., Jr.; Brock, F. J.; Melfi, L. T., Jr.

    1975-01-01

    An electron emission control circuit of the switching regulator type operating at 100 kHz has been developed which maintains a constant emission current within 0.1% for a cathode power demand variation of approximately 100%. The power output stage has an efficiency of 67%, and the overall efficiency is 45% when driving a thoria-coated iridium cathode having a nominal resistance at operating temperature of 2.5 ohms. Under optimum conditions, the bus power demand is 1.75 W. The circuit is useful in controlling the electron emission current of ion sources in applications which involve a substantial variation of the cathode work function, such as oxygen partial pressure measurements over a large dynamic range.

  18. Release and dispersion of vegetation and peat fire emissions in the atmosphere over Indonesia 1997/1998

    Directory of Open Access Journals (Sweden)

    B. Langmann

    2004-01-01

    Full Text Available Smoke-haze episodes caused by vegetation and peat fires affect parts of Indonesia every year with significant impacts on human health and climate. Particularly fires in degenerated peat areas release huge amounts of trace gases, e.g. CO2, CO and CH4, and particles into the atmosphere, exceeding by far the emissions per unit area from fires in surface vegetation. However, only limited information is available about the current distribution of pristine and degenerated peat areas in Indonesia, their depth, drainage condition and modification by fire. Particularly during the strong El Niño event in 1997/1998 a huge uncertainty exists about the contribution of Indonesian peat fire emissions to the measured increase of atmospheric CO2, as the published estimates of the peat area burned differ considerably. In this paper we study the contribution of peat fire emissions in Indonesia during the El Niño event 1997/1998. A regional three-dimensional atmosphere-chemistry model is applied over Indonesia using two emission estimates. These vegetation and peat fire emission inventories for Indonesia are set up in 0.5° resolution in weekly intervals and differ only in the size of the fire affected peat areas. We evaluate simulated rainfall and particle concentrations by comparison with observations to draw conclusions on the total carbon emissions released from the vegetation and peat fires in Indonesia in 1997/1998.

  19. Release and dispersion of vegetation and peat fire emissions in the atmosphere over Indonesia 1997/1998

    Science.gov (United States)

    Langmann, B.; Heil, A.

    2004-11-01

    Smoke-haze episodes caused by vegetation and peat fires affect parts of Indonesia every year with significant impacts on human health and climate. Particularly fires in degenerated peat areas release huge amounts of trace gases, e.g. CO2, CO and CH4, and particles into the atmosphere, exceeding by far the emissions per unit area from fires in surface vegetation. However, only limited information is available about the current distribution of pristine and degenerated peat areas in Indonesia, their depth, drainage condition and modification by fire. Particularly during the strong El Niño event in 1997/1998 a huge uncertainty exists about the contribution of Indonesian peat fire emissions to the measured increase of atmospheric CO2, as the published estimates of the peat area burned differ considerably. In this paper we study the contribution of peat fire emissions in Indonesia during the El Niño event 1997/1998. A regional three-dimensional atmosphere-chemistry model is applied over Indonesia using two emission estimates. These vegetation and peat fire emission inventories for Indonesia are set up in 0.5° resolution in weekly intervals and differ only in the size of the fire affected peat areas. We evaluate simulated rainfall and particle concentrations by comparison with observations to draw conclusions on the total carbon emissions released from the vegetation and peat fires in Indonesia in 1997/1998.

  20. Enhanced control of mercury emissions through modified speciation

    Energy Technology Data Exchange (ETDEWEB)

    Livengood, C.D.; Mendelsohn, M.H.

    1997-07-01

    In anticipation of possible regulations regarding mercury emissions, research efforts sponsored by DOE, EPRI, and others are investigating the risks posed by mercury emissions, improved techniques for measuring those emissions, and possible control measures. The focus in the control research is on techniques that can be used in conjunction with existing flue-gas-cleanup (FGC) systems in order to minimize additional capital costs and operational complexity. Argonne National Laboratory has supported the DOE Fossil Energy Program for over 15 years with research on advanced environmental control technologies. The emphasis in Argonne`s work has been on integrated systems that combine control of several pollutants. Specific topics have included spray drying for sulfur dioxide and particulate-matter control with high-sulfur coal, combined sulfur dioxide and nitrogen oxides control technologies, and techniques to enhance mercury control in existing FGC systems. The latter area has focused on low-cost dry sorbents for use with fabric filters or electrostatic precipitators and techniques for improving the capture of mercury in wet flue-gas desulfurization (FGD) systems. This paper presents results from recent work that has studied the effects of several oxidizing agents in combination with typical flue-gas species (e.g., nitrogen oxides and sulfur dioxide) on the oxidation of Hg{sup 0}.

  1. Controlling satellite communication system unwanted emissions in congested RF spectrum

    Science.gov (United States)

    Olsen, Donald; Heymann, Roger

    2007-09-01

    The International Telecommunication Union (ITU), a United Nations (UN) agency, is the agency that, under an international treaty, sets radio spectrum usage regulations among member nations. Within the United States of America (USA), the organization that sets regulations, coordinates an application for use, and provides authorization for federal government/agency use of the radio frequency (RF) spectrum is the National Telecommunications and Information Administration (NTIA). In this regard, the NTIA defines which RF spectrum is available for federal government use in the USA, and how it is to be used. The NTIA is a component of the United States (U.S.) Department of Commerce of the federal government. The significance of ITU regulations is that ITU approval is required for U.S. federal government/agency permission to use the RF spectrum outside of U.S. boundaries. All member nations have signed a treaty to do so. U.S. federal regulations for federal use of the RF spectrum are found in the Manual of Regulations and Procedures for Federal Radio Frequency Management, and extracts of the manual are found in what is known as the Table of Frequency Allocations. Nonfederal government and private sector use of the RF spectrum within the U.S. is regulated by the Federal Communications Commission (FCC). There is a need to control "unwanted emissions" (defined to include out-of-band emissions, which are those immediately adjacent to the necessary and allocated bandwidth, plus spurious emissions) to preclude interference to all other authorized users. This paper discusses the causes, effects, and mitigation of unwanted RF emissions to systems in adjacent spectra. Digital modulations are widely used in today's satellite communications. Commercial communications sector standards are covered for the most part worldwide by Digital Video Broadcast - Satellite (DVB-S) and digital satellite news gathering (DSNG) evolutions and the second generation of DVB-S (DVB-S2) standard

  2. Inverse modelling of European CH4 and N2O emissions 2006-2012 using different inverse models and improved atmospheric observations

    Science.gov (United States)

    Bergamaschi, Peter; Karstens, Ute; Koffi, Ernest; Saunois, Marielle; Arnold, Timothy; Manning, Alistair; Tsuruta, Aki; Berchet, Antoine; Vermeulen, Alex; Janssens-Maenhout, Greet; Hammer, Samuel; Levin, Ingeborg; Schmidt, Martina

    2016-04-01

    We present top-down estimates of European CH4 and N2O emissions for 2006-2012, based on the new quality controlled and harmonized data set from 18 European atmospheric monitoring stations generated within the European FP7 project InGOS ("Integrated non-CO2 Greenhouse gas Observing System"). We applied an ensemble of 7 different inverse models for CH4 (and 4 for N2O), and performed four different inversion experiments, investigating the impact of different sets of stations and the use of 'a priori' information on emissions. The inverse models infer total CH4 emissions of 28.4 ± 6.4 (2σ) Tg CH4 yr‑1 for the EU-28 for 2006-2012 from the 4 inversion experiments. For comparison, total anthropogenic CH4 emissions reported to UNFCCC ('bottom-up', based on statistical data and emissions factors) amount to only 19.0 - 20.9 Tg CH4 yr‑1 for the same period. A potential explanation for the discrepancy between the 'bottom-up' and 'top-down' estimates could be the contribution of natural sources, such as peatlands, wetlands, and wet soils, which might have been underestimated in previous analyses. The hypothesis of significant natural emissions is supported by the finding that the inversions yield significant seasonal cycles of derived CH4 emissions with maximum in summer, while anthropogenic CH4 emissions are assumed to have much lower seasonal variability. Furthermore we investigate potential biases of the flux inversions by comparing model simulations with regular aircraft profiles at 4 European sites and the 'Infrastructure for Measurement of the European Carbon Cycle (IMECC)' aircraft campaign. For N2O, for which uncertainties of bottom-up inventories are very large - typically on the order of 100% for the total N2O emissions per country (mainly due to N2O emissions from agricultural soils) - our results demonstrate that atmospheric measurements and inverse modelling can significantly reduce the uncertainties. Despite the large uncertainties in the bottom

  3. Optimal control of photoelectron emission by realistic waveforms

    CERN Document Server

    Solanpää, Janne; Räsänen, Esa

    2016-01-01

    Recent experimental techniques in multicolor waveform synthesis allow the temporal shaping of strong femtosecond laser pulses with applications in the control of quantum mechanical processes in atoms, molecules, and nanostructures. Prediction of the shapes of the optimal waveforms can be done computationally using quantum optimal control theory (QOCT). In this work we bring QOCT to experimental feasibility by providing an optimal control scheme with realistic pulse representation. We apply the technique to optimal control of above-threshold photoelectron emission from a one-dimensional hydrogen atom. By mixing different spectral channels and thus lowering the intensity requirements for individual channels, the resulting optimal pulses can extend the cutoff energies by at least up to 50% and bring up the electron yield by several orders of magnitude. Insights into the electron dynamics for optimized photoelectron emission are obtained with a semiclassical two-step model.

  4. Controlled spontaneous emission in erbium-doped microphotonic materials

    NARCIS (Netherlands)

    Kalkman, Jeroen

    2005-01-01

    Erbium is a rare-earth metal that, when incorporated in a solid, can emit light at a wavelength of 1.5 μm. It plays a key role in current day telecommunication technology as the principle ingredient of optical fiber amplifiers. In this thesis the control of the Er spontaneous emission in three diffe

  5. Emissions inventories and options for control SUMMARY REPORT

    NARCIS (Netherlands)

    Swart RJ; Amstel AR van; Born GJ van den; Kroeze C; MTV; LAE

    1994-01-01

    This report is the final summary report of the project "Social causes of the greenhouse effect ; emissions inventories and options for control", funded by the National Research Programme on Global Air Pollution and Climate Change (NRP) and the Environment Directorate of the Ministry of Housing, Phys

  6. Atmospheric observations for quantifying emissions of point-source synthetic greenhouse gases (CF4, NF3 and HFC-23)

    Science.gov (United States)

    Arnold, Tim; Manning, Alistair J.; Li, Shanlan; Kim, Jooil; Park, Sunyoung; Fraser, Paul J.; Mitrevski, Blagoj; Steele, L. Paul; Krummel, Paul B.; Mühle, Jens; Weiss, Ray F.

    2016-04-01

    The fluorinated species carbon tetrafluoride (CF4; PFC-14), nitrogen trifluoride (NF3) and trifluoromethane (CHF3; HFC-23) are potent greenhouse gases with 100-year global warming potentials of 6,630, 16,100 and 12,400, respectively. Unlike the majority of CFC-replacement compounds that are emitted from fugitive and mobile emission sources, these gases are largely emitted from large single point sources - semiconductor manufacturing facilities (all three), aluminium smelting plants (CF4) and chlorodifluoromethane factories (HFC-23). In this work we show the potential for atmospheric measurements to understand regional sources of these gases and to highlight emission 'hotspots'. We target our analysis on measurements from two Advanced Global Atmospheric Gases Experiment (AGAGE) long term monitoring sites that are particularly sensitive to regional emissions of these gases: Gosan on Jeju Island in the Republic of Korea and Cape Grim on Tasmania in Australia. These sites measure CF4, NF3 and HFC-23 alongside a suite of greenhouse and stratospheric ozone depleting gases every two hours using automated in situ gas-chromatography mass-spectrometry instrumentation. We couple each measurement to an analysis of air history using the regional atmospheric transport model NAME (Numerical Atmospheric dispersion Modelling Environment) driven by 3D meteorology from the Met Office's Unified Model, and use a Bayesian inverse method (InTEM - Inversion Technique for Emission Modelling) to calculate yearly emission changes over a decade (2005-2015) at high spatial resolution. At present these gases make a small contribution to global radiative forcing, however, given that their impact could rise significantly and that point sources of such gases can be mitigated, atmospheric monitoring could be an important tool for aiding emissions reduction policy.

  7. Mercury emission, control and measurement from coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Wei-Ping [North China Electric Power Univ., Beijing (China). School of Energy and Power Engineering; Western Kentucky Univ., Bowling Green, KY (United States). Inst. for Combustion Science and Environmental Technology; Cao, Yan [Western Kentucky Univ., Bowling Green, KY (United States). Inst. for Combustion Science and Environmental Technology; Zhang, Kai [North China Electric Power Univ., Beijing (China). School of Energy and Power Engineering

    2013-07-01

    Coal-fired electric power generation accounts for 65% of U.S. emissions of sulfur dioxide (SO2), 22% of nitrogen oxides (NOx), and 37% of mercury (Hg). The proposed Clear Air Interstate Rule (CAIR) and Clean Air Mercury Rule (CAMR) will attempt to regulate these emissions using a cap-and-trade program to replace a number of existing regulatory requirements that will impact this industry over the next decade. Mercury emissions remain the largest source that has not yet been efficiently controlled, in part because this is one of the most expensive to control. Mercury is a toxic, persistent pollutant that accumulates in the food chain. During the coal combustion process, when both sampling and accurate measurements are challenging, we know that mercury is present in three species: elemental, oxidized and particulate. There are three basic types of mercury measurement methods: Ontario Hydro Method, mercury continuous emission monitoring systems (CEMS) and sorbent-based monitoring. Particulate mercury is best captured by electrostatic precipitators (ESP). Oxidized mercury is best captured in wet scrubbers. Elemental mercury is the most difficult to capture, but selective catalytic reduction units (SCRs) are able to convert elemental mercury to oxidized mercury allowing it to be captured by wet flue gas desulfurization (FGD). This works well for eastern coals with high chlorine contents, but this does not work well on the Wyoming Powder River Basin (PRB) coals. However, no good explanation for its mechanism, correlations of chlorine content in coal with SCR performance, and impacts of higher chlorine content in coal on FGD re-emission are available. The combination of SCR and FGD affords more than an 80% reduction in mercury emissions in the case of high chlorine content coals. The mercury emission results from different coal ranks, boilers, and the air pollution control device (APCD) in power plant will be discussed. Based on this UAEPA new regulation, most power plants

  8. CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express

    Science.gov (United States)

    Piccialli, A.; López-Valverde, M. A.; Määttänen, A.; González-Galindo, F.; Audouard, J.; Altieri, F.; Forget, F.; Drossart, P.; Gondet, B.; Bibring, J. P.

    2016-06-01

    We report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3 μm is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 110 km. The main value of OMEGA observations is that they provide simultaneously spectral information and good spatial sampling of the CO2 emission. In this study we analyzed 98 dayside limb observations spanning over more than 3 Martian years, with a very good latitudinal and longitudinal coverage. Thanks to the precise altitude sounding capabilities of OMEGA, we extracted vertical profiles of the non-local thermodynamic equilibrium (non-LTE) emission at each wavelength and we studied their dependence on several geophysical parameters, such as the solar illumination and the tangent altitude. The dependence of the non-LTE emission on solar zenith angle and altitude follows a similar behavior to that predicted by the non-LTE model. According to our non-LTE model, the tangent altitude of the peak of the CO2 emission varies with the thermal structure, but the pressure level where the peak of the emission is found remains constant at ˜0.03 ± 0.01 Pa, . This non-LTE model prediction has been corroborated by comparing SPICAM and OMEGA observations. We have shown that the seasonal variations of the altitude of constant pressure levels in SPICAM stellar occultation retrievals correlate well with the variations of the OMEGA peak emission altitudes, although the exact pressure level cannot be defined with the spectroscopy for the investigation of the characteristics of the atmosphere of Venus (SPICAM) nighttime data. Thus, observed changes in the altitude of the peak emission provide us information on the altitude of the 0.03 Pa pressure level. Since the pressure at a given altitude is dictated by the thermal structure below, the tangent altitude of the peak emission represents

  9. Emission estimates for some acidifying and greenhouse gases and options for their control in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Pipatti, R. [VTT Energy, Espoo (Finland). Energy Systems

    1998-11-01

    This thesis presents estimates and options for control of anthropogenic ammonia (NH{sub 3}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O) and some halocarbon emissions in Finland. Ammonia is an air pollutant which contributes to both acidification and nitrogen eutrophication of ecosystems. Its emissions are mainly caused by livestock manure. In Finland the anthropogenic emissions of NH{sub 3} have been estimated to be approximately 44 Gg in 1985 and 43 Gg in 1990. In the 1990`s the emissions have declined due to the reduced number of cattle and voluntary implementation of emission reducing measures. The impact of NH{sub 3} emissions on acidification is serious but in Finland it is less than the impact of the other acidifying gases sulphur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}). All three gases and their transformation products are transported by the atmosphere up to distances of hundreds or even more than a thousand kilometres. NH{sub 3} emissions can be reduced with relatively cost-effective measures and the measures can partly replace the implementation of more costly abatement measures on SO{sub 2} and NO{sub x} emissions needed to lower the acidifying deposition in Finland. The other gases studied in this thesis are greenhouse gases. Some of the gases also deplete stratospheric ozone. Finnish anthropogenic CH{sub 4} emissions have been estimated to be around 250 Gg per year during the 1990`s. The emissions come mainly from landfills and agricultural sources (enteric fermentation and manure). The significance of other CH{sub 4} sources in Finland is minor. The potential to reduce the Finnish CH{sub 4} emissions is estimated to be good. Landfill gas recovery offers an option to reduce the emissions significantly at negligible cost if the energy produced can be utilised in electricity and/or heat production. Measures directed at reducing the emissions from livestock manure management are more costly, and the achievable reduction in the emissions

  10. Estimates of Methane and Ethane Emissions from the Barnett Shale Using Atmospheric Measurements

    Science.gov (United States)

    Karion, A.; Sweeney, C.; Kort, E. A.; Shepson, P. B.; Conley, S. A.; Lauvaux, T.; Davis, K. J.; Deng, A.; Lyon, D. R.; Smith, M. L.

    2015-12-01

    Recent development of horizontal drilling technology and advances in hydraulic fracturing techniques by the oil and gas industry have dramatically increased onshore U.S. natural gas and oil production in the last several years. The primary component of natural gas is methane (CH4), a powerful greenhouse gas; therefore, natural gas leakage into the atmosphere affects its climate impact. We present estimates of regional methane (CH4) and ethane (C2H6) emissions from oil and natural gas operations in the Barnett Shale, Texas, made in March and October 2013 as part of the Environmental Defense Fund's Barnett Coordinated Campaign. The Barnett is one of the largest production basins in the United States, with 8% of total U.S. natural gas production, and thus, our results represent a crucial step toward determining the greenhouse gas footprint of U.S. onshore natural gas production. Using a mass balance approach on eight different flight days the total CH4 emissions for the region are estimated to be 76 ± 13x 103 kg/hr, or 0.66 ± 0.11 Tg CH4 /yr; (95% CI). Repeated mass balance flights in the same basin on eight different days and two seasons demonstrate the consistency of the mass balance approach. On the basis of airborne C2H6 and CH4 measurements, we find 71-85% of the observed CH4 emissions quantified in the Barnett Shale are derived from fossil sources. The average C2H6 flux was 6.6 ± 0.2 x 103 kg/hr and consistent across six days in spring and fall of 2013. This result is the first demonstration of this approach for C2H6. We estimate that 60±11x103 kg CH4/hr (95% CI) are emitted by natural gas and oil operations, including production, processing, and distribution in the urban areas of Dallas and Fort Worth. This estimate is significantly higher than emissions reported by the EDGAR inventory or by industry to EPA's Greenhouse Gas Reporting Program.

  11. Four-dimensional variational data assimilation for inverse modelling of atmospheric methane emissions: method and comparison with synthesis inversion

    Directory of Open Access Journals (Sweden)

    J. F. Meirink

    2008-11-01

    Full Text Available A four-dimensional variational (4D-Var data assimilation system for inverse modelling of atmospheric methane emissions is presented. The system is based on the TM5 atmospheric transport model. It can be used for assimilating large volumes of measurements, in particular satellite observations and quasi-continuous in-situ observations, and at the same time it enables the optimization of a large number of model parameters, specifically grid-scale emission rates. Furthermore, the variational method allows to estimate uncertainties in posterior emissions. Here, the system is applied to optimize monthly methane emissions over a 1-year time window on the basis of surface observations from the NOAA-ESRL network. The results are rigorously compared with an analogous inversion by Bergamaschi et al. (2007, which was based on the traditional synthesis approach. The posterior emissions as well as their uncertainties obtained in both inversions show a high degree of consistency. At the same time we illustrate the advantage of 4D-Var in reducing aggregation errors by optimizing emissions at the grid scale of the transport model. The full potential of the assimilation system is exploited in Meirink et al. (2008, who use satellite observations of column-averaged methane mixing ratios to optimize emissions at high spatial resolution, taking advantage of the zooming capability of the TM5 model.

  12. Solar wind control of Jupiter's hectometric radio emission

    Science.gov (United States)

    Barrow, C. H.; Desch, M. D.

    1989-01-01

    Radio, plasma, and magnetic field data obtained by Voyager 1 and Voyager 2 were used to examine the manner in which the Jovian hectometric radio emission (HOM) is controlled by the solar wind. Using the method of superposed epochs, it was found that the higher energy HOM is correlated with the IMF as well as with the solar wind density and pressure. However, unlike the Io-independent decametric radio emission (Non-Io DAM), the HOM displayed no correlation with the solar wind velocity, although this radio component appear to be also influenced by the IMF. The results suggest separate HOM amd Non-Io DAM sources.

  13. Controlling spontaneous emission with plasmonic optical patch antennas

    CERN Document Server

    Belacel, C; Bigourdan, F; Marquier, F; Hugonin, J -P; de Vasconcellos, S Michaelis; Lafosse, X; Coolen, L; Schwob, C; Javaux, C; Dubertret, B; Greffet, J -J; Senellart, P; Maitre, A

    2012-01-01

    We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk 30 nm above a thick gold layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending of the antenna size. Considering the double dipole structure of the emitters, this corresponds to a Purcell factor up to 80 for dipoles perpendicular to the disk.

  14. Managing agricultural emissions to the atmosphere: State of the science, fate and mitigation, and identifying research gaps

    Science.gov (United States)

    The impact of agriculture on regional air quality creates significant challenges to sustainability of food supplies and to the quality of national resources. Agricultural emissions to the atmosphere can lead to many nuisances, such as smog, haze, or offensive odors. They can also create more seriou...

  15. Comparison of the RAINS Emission Control Cost Curves for Air Pollutants with Emission Control Costs Computed by the GAINS Model

    OpenAIRE

    F. Wagner; Schoepp, W.

    2007-01-01

    This paper compares cost curves of SO2, NOx and PM2.5 emission controls generated with the RAINS (Regional Air Pollution Information and Simulation) model with cost estimates obtained from the GAINS (Greenhouse Gas - Air Pollution Interactions and Synergies) model. Based on the same set of input data, results from both models are very similar, and differences are considered as insignificant.

  16. Modeling atmospheric transport of CO2 at High Resolution to estimate the potentialities of spaceborne observation to monitor anthropogenic emissions

    Science.gov (United States)

    Ciais, P.; Chimot, J.; Klonecki, A.; Prunet, P.; Vinuessa, J.; Nussli, C.; Breon, F.

    2010-12-01

    There is a crucial and urgent need to quantify and monitor anthropogenic fossil fuel emissions of CO2. Spaceborne measurements, such as those from GOSAT or the forthcoming OCO-2, or other space missions in preparation, could provide the necessary information, in particular over regions with few in-situ measurements of atmospheric concentration are too scarce. Contrarily to biogenic flux, anthropogenic emissions are highly heterogeneous in space with typical values that vary by several orders of magnitudes. A proper analysis of the impact of anthropogenic emissions on the atmospheric concentration of CO2 therefore requires a high spatial resolution, typically of a few km. Simulations of the transport of fossil CO2 plumes were performed with a resolution of 1 km over the main industrialized regions of France, and using other models of lower resolution to account for the influence of distant sources advected into the area of interest. The results clearly show the plumes from intense yet localized sources, such as urban areas or power plants, and how their structures vary with the meteorology (wind speed and direction). They also show that the plume from distant sources, such as the large emission from Northern Europe, may sometime mask the local plume, even from large cities like Paris or Lyon. These atmospheric transport simulations are then sampled according to cloud cover, spaceborne instrument sampling and typical errors, to analyze the information content of the remote sensing data and how they can improve the current knowledge on anthropogenic emissions.

  17. OXIDATION BEHAVIOR OF KOVAR ALLOY IN CONTROLLED ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Controlled oxidation experiments were performed on Kovar alloy by changing oxi-dation atmosphere, temperature, and exposure time to produce films with different oxide type and thickness. The results indicated that single Fe3O4 and single FeO were respectively obtained when Kovar alloy was oxidized in N2-2.31%H2O-0.95%H2 at 500℃ and in N2-2.31%H2O-O.5%H2 at 1000℃, and all kinetic curves followed linear relation; mixed oxides of FeO and Fe3O4 formed when Kovar was oxidized in N2-2.31%H2O at 1000℃, and parabolic kinetics were obeyed. Analysis of metal-lographic cross section of oxides indicated that oxygen diffusion inward through the oxide scale is responsible for intergranular oxide, which had formed beneath the oxide scales when the oxide products were mixed oxides of FeO and Fe3O4, and which did not occur when the oxide was single FeO or Fe3O4. The oxidation model was also established.

  18. Effect of reed canary grass cultivation on greenhouse gas emission from peat soil at controlled rewetting

    Directory of Open Access Journals (Sweden)

    S. Karki

    2014-09-01

    Full Text Available Cultivation of bioenergy crops in rewetted peatland (paludiculture is considered as a possible land use option to mitigate greenhouse gas (GHG emissions. However, bioenergy crops like reed canary grass (RCG can have a complex influence on GHG fluxes. Here we determined the effect of RCG cultivation on GHG emission from peatland rewetted to various extents. Mesocosms were manipulated to three different ground water levels (GWL, i.e., 0, −10 and −20 cm below the soil surface in a controlled semi-field facility. Emissions of CO2 (ecosystem respiration, ER, CH4 and N2O from mesocosms with RCG and bare soil were measured at weekly to fortnightly intervals with static chamber techniques for a period of one year. Cultivation of RCG increased both ER and CH4 emissions, but decreased the N2O emissions. The presence of RCG gave rise to 69, 75 and 85% of total ER at −20, −10 and 0 cm GWL, respectively However, this difference was due to decreased soil respiration at the rising GWL as the plant-derived CO2 flux was similar at all three GWL. For methane, 70–95% of the total emission was due to presence of RCG, with the highest contribution at −20 cm GWL. In contrast, cultivation of RCG decreased N2O emission by 33–86% with the major reductions at −10 and −20 cm GWL. In terms of global warming potential, the increase in CH4 emissions due to RCG cultivation was more than off-set by the decrease in N2O emissions at −10 and −20 cm GWL; at 0 cm GWL the CH4 emissions was offset only by 23%. CO2 emissions from ER obviously were the dominant RCG-derived GHG flux, but above-ground biomass yields, and preliminary measurements of gross photosynthetic production, show that ER could be more than balanced due to the uptake of CO2 by RCG. Our results support that RCG cultivation could be a good land use option in terms of mitigating GHG emission from rewetted peatlands, potentially turning these ecosystems into a sink of atmospheric CO2.

  19. Effect of reed canary grass cultivation on greenhouse gas emission from peat soil at controlled rewetting

    Science.gov (United States)

    Karki, S.; Elsgaard, L.; Lærke, P. E.

    2015-01-01

    Cultivation of bioenergy crops in rewetted peatland (paludiculture) is considered as a possible land use option to mitigate greenhouse gas (GHG) emissions. However, bioenergy crops like reed canary grass (RCG) can have a complex influence on GHG fluxes. Here we determined the effect of RCG cultivation on GHG emission from peatland rewetted to various extents. Mesocosms were manipulated to three different ground water levels (GWLs), i.e. 0, -10 and -20 cm below the soil surface in a controlled semi-field facility. Emissions of CO2 (ecosystem respiration, ER), CH4 and N2O from mesocosms with RCG and bare soil were measured at weekly to fortnightly intervals with static chamber techniques for a period of 1 year. Cultivation of RCG increased both ER and CH4 emissions, but decreased the N2O emissions. The presence of RCG gave rise to 69, 75 and 85% of total ER at -20, -10 and 0 cm GWL, respectively. However, this difference was due to decreased soil respiration at the rising GWL as the plant-derived CO2 flux was similar at all three GWLs. For methane, 70-95% of the total emission was due to presence of RCG, with the highest contribution at -20 cm GWL. In contrast, cultivation of RCG decreased N2O emission by 33-86% with the major reductions at -10 and -20 cm GWL. In terms of global warming potential, the increase in CH4 emissions due to RCG cultivation was more than offset by the decrease in N2O emissions at -10 and -20 cm GWL; at 0 cm GWL the CH4 emissions was offset only by 23%. CO2 emissions from ER were obviously the dominant RCG-derived GHG flux, but above-ground biomass yields, and preliminary measurements of gross photosynthetic production, showed that ER could be more than balanced due to the photosynthetic uptake of CO2 by RCG. Our results support that RCG cultivation could be a good land use option in terms of mitigating GHG emission from rewetted peatlands, potentially turning these ecosystems into a sink of atmospheric CO2.

  20. Link between local scale BC emissions and large scale atmospheric solar absorption

    Directory of Open Access Journals (Sweden)

    P. S. Praveen

    2011-07-01

    Full Text Available Project Surya has documented indoor and outdoor concentrations of black carbon (BC from traditional biomass burning cook stoves in a rural village located in the Indo-Gangetic Plains (IGP region of N. India from November 2009- September 2010. In this paper, we systematically document the link between local scale aerosol properties and column averaged regional aerosol optical properties and atmospheric radiative forcing. We report observations from the first phase of Project Surya to estimate the source dependent (biomass and fossil fuels aerosol optical properties from local to regional scale. Data were collected using surface based observations of BC, organic carbon (OC, aerosol light absorption, scattering coefficient at the Surya village (SVI_1 located in IGP region, and satellite and AERONET observations at the regional scale (IGP. The daily mean BC concentrations at SVI_1 showed the large increase of BC during the dry season (December to February with values reaching 35 μg m−3. Space based LIDAR data reveal how the biomass smoke is trapped within the first kilometre during the dry season and its extension to above 5 km during the pre-monsoon season. As a result during the dry season, the variance in the daily mean SSA and column aerosol optical properties at the local IGP site correlated (with slopes in the range of 0.85 to 1.06 and R2>0.4 well with the "IGP_AERONET" (mean of six AERONET sites, thus suggesting in-situ observations at few locations can be used to infer spatial mean forcing. The atmospheric forcing due to BC and OC exceeded 20 W m−2 during all months from November to May, leading to the deduction that elimination of cook stove smoke emissions through clean cooking technologies will likely have a major positive impact on health and the regional climate.

  1. "APEC Blue" association with emission control and meteorological conditions detected by multi-scale statistics

    Science.gov (United States)

    Wang, Ping; Dai, Xin-Gang

    2016-09-01

    The term "APEC Blue" has been created to describe the clear sky days since the Asia-Pacific Economic Cooperation (APEC) summit held in Beijing during November 5-11, 2014. The duration of the APEC Blue is detected from November 1 to November 14 (hereafter Blue Window) by moving t test in statistics. Observations show that APEC Blue corresponds to low air pollution with respect to PM2.5, PM10, SO2, and NO2 under strict emission-control measures (ECMs) implemented in Beijing and surrounding areas. Quantitative assessment shows that ECM is more effective on reducing aerosols than the chemical constituents. Statistical investigation has revealed that the window also resulted from intensified wind variability, as well as weakened static stability of atmosphere (SSA). The wind and ECMs played key roles in reducing air pollution during November 1-7 and 11-13, and strict ECMs and weak SSA become dominant during November 7-10 under weak wind environment. Moving correlation manifests that the emission reduction for aerosols can increase the apparent wind cleanup effect, leading to significant negative correlations of them, and the period-wise changes in emission rate can be well identified by multi-scale correlations basing on wavelet decomposition. In short, this case study manifests statistically how human interference modified air quality in the mega city through controlling local and surrounding emissions in association with meteorological condition.

  2. Nitrous oxide (N2O). Emission inventory and options for control in the Netherlands

    NARCIS (Netherlands)

    Kroeze C; LAE

    1994-01-01

    This study was initiated to overview current knowledge on nitrous oxide (N2O). The report reviews atmospheric behaviour of N2O, global sources and sinks, Dutch emissions in 1990, options to reduce emissions, and past and future emissions. Despite the uncertainties involved, it is likely that without

  3. Effects of a Relativistic Electron Beam Interaction with the Upper Atmosphere: Ionization, X-Rays, and Optical Emissions

    Science.gov (United States)

    Marshall, R. A.; Nicolls, M. J.; Sanchez, E. R.; Lehtinen, N. G.; Neilson, J.

    2014-12-01

    An artificial beam of relativistic (0.5--10 MeV) electrons has been proposed as an active experiment in the ionosphere and magnetosphere, with applications to magnetic field-line tracing, studies of wave-particle interactions, and beam-atmosphere interactions. The beam-atmosphere interaction, while a scientific endeavor of its own, also provides key diagnostics for other experiments. We present results of Monte Carlo simulations of the interaction of a beam of relativistic electrons with the upper atmosphere as they are injected downwards from a notional high altitude (thermospheric / ionospheric) injection platform. The beam parameters, defined by realistic parameters of a compact linear accelerator, are used to create a distribution of thousands of electrons. Each electron is injected downwards from 300 km altitude towards the dense atmosphere, where it undergoes elastic and inelastic collisions, leading to secondary ionization, optical emissions, and X-rays via bremsstrahlung. Here we describe the Monte Carlo model and present calculations of diagnostic outputs, including optical emissions, X-ray fluxes, secondary ionization, and backscattered energetic electron fluxes. Optical emissions are propagated to the ground through the lower atmosphere, including the effects of atmospheric absorption and scattering, to estimate the brightness of the emission column for a given beam current and energy. Similarly, X-ray fluxes are propagated to hypothetical detectors on balloons and satellites, taking into account Compton scattering and photoabsorption. Secondary ionization is used to estimate the radar signal returns from various ground-based radar facilities. Finally, simulated backscattered electron fluxes are measured at the injection location. The simulation results show that for realizable accelerator parameters, each of these diagnostics should be readily detectable by appropriate instruments.

  4. A sparse reconstruction method for the estimation of multiresolution emission fields via atmospheric inversion

    Directory of Open Access Journals (Sweden)

    J. Ray

    2014-08-01

    Full Text Available We present a sparse reconstruction scheme that can also be used to ensure non-negativity when fitting wavelet-based random field models to limited observations in non-rectangular geometries. The method is relevant when multiresolution fields are estimated using linear inverse problems. Examples include the estimation of emission fields for many anthropogenic pollutants using atmospheric inversion or hydraulic conductivity in aquifers from flow measurements. The scheme is based on three new developments. Firstly, we extend an existing sparse reconstruction method, Stagewise Orthogonal Matching Pursuit (StOMP, to incorporate prior information on the target field. Secondly, we develop an iterative method that uses StOMP to impose non-negativity on the estimated field. Finally, we devise a method, based on compressive sensing, to limit the estimated field within an irregularly shaped domain. We demonstrate the method on the estimation of fossil-fuel CO2 (ffCO2 emissions in the lower 48 states of the US. The application uses a recently developed multiresolution random field model and synthetic observations of ffCO2 concentrations from a limited set of measurement sites. We find that our method for limiting the estimated field within an irregularly shaped region is about a factor of 10 faster than conventional approaches. It also reduces the overall computational cost by a factor of two. Further, the sparse reconstruction scheme imposes non-negativity without introducing strong nonlinearities, such as those introduced by employing log-transformed fields, and thus reaps the benefits of simplicity and computational speed that are characteristic of linear inverse problems.

  5. International global atmospheric chemistry (IGAC) program global emissions inventory activity (GEIA). Proceedings of the IGAC/GEIA workshop on global emission inventory

    Energy Technology Data Exchange (ETDEWEB)

    Pacyna, J.M. [Norwegian Inst. for Air Research, Lillestroem (Norway); Graedel, T.E. [AT and T Bell Labs., Murray Hill, NJ (United States)

    1992-10-01

    In accordance with the work plan of the International Geosphere-Biosphere Program (IGBP)/International Global Atmospheric Chemistry (IGAC) Global Emission Inventory was organized by the GEIA Secretariat and the Norwegian Institute for Air Research (NILU). The workshop was attended by 34 participants from 9 countries and 3 international organizations. The overall goals of the workshop were to review the progress of work within individual GEIA projects and to plan further activity, as well as to discuss new projects. Major focus was placed on projects related to emissions of acidic components, such as SO{sub 2} and NO{sub x}, and other nitrogen compounds, and volatile organic compounds (VOCs)

  6. 78 FR 36776 - Proposed Information Collection Request; Comment Request; Emission Control System Performance...

    Science.gov (United States)

    2013-06-19

    ... AGENCY Proposed Information Collection Request; Comment Request; Emission Control System Performance... an information collection request (ICR), ``Emission Control System Performance Warranty Regulations and Voluntary Aftermarket Part Certification Program (Renewal)'' (EPA ICR No. 0116.10, OMB Control...

  7. Ozone trends in Atlanta, Georgia - Have emission controls been effective?

    Science.gov (United States)

    Lindsay, Ronald W.; Richardson, Jennifer L.; Chameldes, William L.

    1989-01-01

    Nine years of summertime ozone data from the Atlanta metropolitan area are analyzed and compared to local emissions of volatile organic carbon and nitrogen oxides. Trends from 1979 to 1987 were studied for the number of days per year ozone exceeded the NAAQS standard, the second-highest ozone level observed per year, and the first quartile summertime average ozone observed, as well as the mean difference between the ozone level observed downwind and upwind of the city. Because this last parameter is sensitive to chemical factors but relatively insensitive to the number of days each year with meteorological conditions conducive to ozone formation, its trend may be best suited for determining how effective emission controls have been in reducing O3 in the Atlanta area. In spite of the fact that sizeable reductions have been claimed for volatile organic carbon emissions over the past several years, the data give no indication that ozone levels have decreased and in fact, imply that summertime ozone production may have increased. The results imply that either emissions have not decreased as much as has been claimed or that ozone is not sensitive to anthropogenic volatile organic carbon emissions.

  8. Control of Several Emissions during Olive Pomace Thermal Degradation

    Directory of Open Access Journals (Sweden)

    Teresa Miranda

    2014-10-01

    Full Text Available Biomass plays an important role as an energy source, being an interesting alternative to fossil fuels due to its environment-friendly and sustainable characteristics. However, due to the exposure of customers to emissions during biomass heating, evolved pollutants should be taken into account and controlled. Changing raw materials or mixing them with another less pollutant biomass could be a suitable step to reduce pollution. This work studied the thermal behaviour of olive pomace, pyrenean oak and their blends under combustion using thermogravimetric analysis. It was possible to monitor the emissions released during the process by coupling mass spectrometry analysis. The experiments were carried out under non-isothermal conditions at the temperature range 25–750 °C and a heating rate of 20 °C·min−1. The following species were analysed: aromatic compounds (benzene and toluene, sulphur emissions (sulphur dioxide, 1,4-dioxin, hydrochloric acid, carbon dioxide and nitrogen oxides. The results indicated that pollutants were mainly evolved in two different stages, which are related to the thermal degradation steps. Thus, depending on the pollutant and raw material composition, different emission profiles were observed. Furthermore, intensity of the emission profiles was related, in some cases, to the composition of the precursor.

  9. Quantifying missing annual emission sources of heavy metals in the United Kingdom with an atmospheric transport model

    Energy Technology Data Exchange (ETDEWEB)

    Dore, Anthony J., E-mail: todo@ceh.ac.uk [Centre for Ecology and Hydrology (United Kingdom); Hallsworth, Stephen [Centre for Ecology and Hydrology (United Kingdom); McDonald, Alan G. [Scottish Environment Protection Agency (United Kingdom); Werner, Małgorzata; Kryza, Maciej [Department of Climatology and Atmosphere Protection, University of Wrocław (Poland); Abbot, John [Ricardo-AEA, Didcot (United Kingdom); Nemitz, Eiko [Centre for Ecology and Hydrology (United Kingdom); Dore, Christopher J. [Aether Ltd., Oxford (United Kingdom); Malcolm, Heath; Vieno, Massimo; Reis, Stefan; Fowler, David [Centre for Ecology and Hydrology (United Kingdom)

    2014-05-01

    An atmospheric chemical transport model was adapted to simulate the concentration and deposition of heavy metals (arsenic, cadmium, chromium, copper, lead, nickel, selenium, vanadium, and zinc) in the United Kingdom. The model showed that wet deposition was the most important process for the transfer of metals from the atmosphere to the land surface. The model achieved a good correlation with annually averaged measurements of metal concentrations in air. The correlation with measurements of wet deposition was less strong due to the complexity of the atmospheric processes involved in the washout of particulate matter which were not fully captured by the model. The measured wet deposition and air concentration of heavy metals were significantly underestimated by the model for all metals (except vanadium) by factors between 2 and 10. These results suggest major missing sources of annual heavy metal emissions which are currently not included in the official inventory. Primary emissions were able to account for only 9%, 21%, 29%, 21%, 36%, 7% and 23% of the measured concentrations for As, Cd, Cr, Cu, Ni, Pb and Zn. A likely additional contribution to atmospheric heavy metal concentrations is the wind driven re-suspension of surface dust still present in the environment from the legacy of much higher historic emissions. Inclusion of two independent estimates of emissions from re-suspension in the model was found to give an improved agreement with measurements. However, an accurate estimate of the magnitude of re-suspended emissions is restricted by the lack of measurements of metal concentrations in the re-suspended surface dust layer. - Highlights: • Concentrations and deposition of 9 heavy metals in the UK were simulated. • Modelled data were well correlated to measured concentrations and deposition. • The model greatly underestimated metal deposition and air concentrations. • Under-estimation was attributed to wind-driven re-suspension of surface dust.

  10. Quantifying missing annual emission sources of heavy metals in the United Kingdom with an atmospheric transport model

    International Nuclear Information System (INIS)

    An atmospheric chemical transport model was adapted to simulate the concentration and deposition of heavy metals (arsenic, cadmium, chromium, copper, lead, nickel, selenium, vanadium, and zinc) in the United Kingdom. The model showed that wet deposition was the most important process for the transfer of metals from the atmosphere to the land surface. The model achieved a good correlation with annually averaged measurements of metal concentrations in air. The correlation with measurements of wet deposition was less strong due to the complexity of the atmospheric processes involved in the washout of particulate matter which were not fully captured by the model. The measured wet deposition and air concentration of heavy metals were significantly underestimated by the model for all metals (except vanadium) by factors between 2 and 10. These results suggest major missing sources of annual heavy metal emissions which are currently not included in the official inventory. Primary emissions were able to account for only 9%, 21%, 29%, 21%, 36%, 7% and 23% of the measured concentrations for As, Cd, Cr, Cu, Ni, Pb and Zn. A likely additional contribution to atmospheric heavy metal concentrations is the wind driven re-suspension of surface dust still present in the environment from the legacy of much higher historic emissions. Inclusion of two independent estimates of emissions from re-suspension in the model was found to give an improved agreement with measurements. However, an accurate estimate of the magnitude of re-suspended emissions is restricted by the lack of measurements of metal concentrations in the re-suspended surface dust layer. - Highlights: • Concentrations and deposition of 9 heavy metals in the UK were simulated. • Modelled data were well correlated to measured concentrations and deposition. • The model greatly underestimated metal deposition and air concentrations. • Under-estimation was attributed to wind-driven re-suspension of surface dust.

  11. Plant physiological and environmental controls over the exchange of acetaldehyde between forest canopies and the atmosphere

    Directory of Open Access Journals (Sweden)

    K. Jardine

    2008-06-01

    Full Text Available We quantified fine scale sources and sinks of gas phase acetaldehyde in two forested ecosystems in the US. During the daytime, the upper canopy behaved as a net source while at lower heights, reduced emission rates or net uptake were observed. At night, uptake generally predominated thoughout the canopies. Net ecosystem emission rates were inversely related to foliar density which influenced the extinction of light and the acetaldehyde compensation point in the canopy. This is supported by branch level studies revealing much higher compensation points in the light than in the dark for poplar (Populus deltoides and holly oak (Quercus ilex implying a higher light/temperature sensitivity for acetaldehyde production relative to consumption. The view of stomata as the major pathway for acetaldehyde exchange is supported by strong linear correlations between branch transpiration rates and acetaldehyde exchange velocities for both species. In addition, natural abundance carbon isotope analysis of gas-phase acetaldehyde during poplar branch fumigation experiments revealed a significant kinetic isotope effect of 5.1±0.3‰, associated with the uptake of acetaldehyde. Similar experiments with dry dead poplar leaves showed no fractionation or uptake of acetaldehyde, confirming that this is only a property of living leaves. We suggest that acetaldehyde belongs to a potentially large list of plant metabolites where stomatal conductance can exert long term control over both emission and uptake rates due to the presence of both source(s and sink(s within the leaf which strongly buffer large changes in concentrations in the substomatal airspace due to changes in stomatal conductance. We conclude that the exchange of acetaldehyde between plant canopies and the atmosphere is fundamentally controlled by ambient acetaldehyde concentrations, stomatal conductance, and the acetaldehyde compensation point.

  12. Plant physiological and environmental controls over the exchange of acetaldehyde between forest canopies and the atmosphere

    Directory of Open Access Journals (Sweden)

    K. Jardine

    2008-11-01

    Full Text Available We quantified fine scale sources and sinks of gas phase acetaldehyde in two forested ecosystems in the US. During the daytime, the upper canopy behaved as a net source while at lower heights, reduced emission rates or net uptake were observed. At night, uptake generally predominated throughout the canopies. Net ecosystem emission rates were inversely related to foliar density due to the extinction of light in the canopy and a respective decrease of the acetaldehyde compensation point. This is supported by branch level studies revealing much higher compensation points in the light than in the dark for poplar (Populus deltoides and holly oak (Quercus ilex implying a higher light/temperature sensitivity for acetaldehyde production relative to consumption. The view of stomata as the major pathway for acetaldehyde exchange is supported by strong linear correlations between branch transpiration rates and acetaldehyde exchange velocities for both species. In addition, natural abundance carbon isotope analysis of gas-phase acetaldehyde during poplar branch fumigation experiments revealed a significant kinetic isotope effect of 5.1±0.3‰ associated with the uptake of acetaldehyde. Similar experiments with dry dead poplar leaves showed no fractionation or uptake of acetaldehyde, confirming that this is only a property of living leaves. We suggest that acetaldehyde belongs to a potentially large list of plant metabolites where stomatal resistance can exert long term control over both emission and uptake rates due to the presence of both source(s and sink(s within the leaf which strongly buffer large changes in concentrations in the substomatal airspace due to changes in stomatal resistance. We conclude that the exchange of acetaldehyde between plant canopies and the atmosphere is fundamentally controlled by ambient acetaldehyde concentrations, stomatal resistance, and the compensation point which is a function of light/temperature.

  13. Revisiting factors controlling methane emissions from high-Arctic tundra

    Directory of Open Access Journals (Sweden)

    M. Mastepanov

    2013-07-01

    Full Text Available The northern latitudes are experiencing disproportionate warming relative to the mid-latitudes, and there is growing concern about feedbacks between this warming and methane production and release from high-latitude soils. Studies of methane emissions carried out in the Arctic, particularly those with measurements made outside the growing season, are underrepresented in the literature. Here we present results of 5 yr (2006–2010 of automatic chamber measurements at a high-Arctic location in Zackenberg, NE Greenland, covering both the growing seasons and two months of the following freeze-in periods. The measurements show clear seasonal dynamics in methane emission. The start of the growing season and the increase in CH4 fluxes were strongly related to the date of snowmelt. Within each particular growing season, CH4 fluxes were highly correlated with the soil temperature (R2 > 0.75, which is probably explained by high seasonality of both variables, and weakly correlated with the water table. The greatest variability in fluxes between the study years was observed during the first part of the growing season. Somewhat surprisingly, this variability could not be explained by commonly known factors controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010 despite large differences in climatic factors (temperature and water table. Late-season bursts of CH4 coinciding with soil freezing in the autumn were observed during at least three years. The cumulative emission during the freeze-in CH4 bursts was comparable in size with the growing season emission for the year 2007, and about one third of the growing season emissions for the years 2009 and 2010. In all three cases the CH4 burst was accompanied by a corresponding episodic increase in CO2 emission, which can compose a significant contribution to the annual CO2

  14. Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

    Directory of Open Access Journals (Sweden)

    Hu eWang

    2015-08-01

    Full Text Available This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors’ group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI combustion, stratification controlled premixed charge compression ignition (PCCI combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fuelled with both high cetane number fuels, such as DME and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition (RCCI/highly premixed charge combustion (HPCC mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

  15. Simulation of radio emission from air showers in atmospheric electric fields

    CERN Document Server

    Buitink, S; Falcke, H; Kuijpers, J

    2010-01-01

    We study the effect of atmospheric electric fields on the radio pulse emitted by cosmic ray air showers. Under fair weather conditions the dominant part of the radio emission is driven by the geomagnetic field. When the shower charges are accelerated and deflected in an electric field additional radiation is emitted. We simulate this effect with the Monte Carlo code REAS2, using CORSIKA-simulated showers as input. In both codes a routine has been implemented that treats the effect of the electric field on the shower particles. We find that the radio pulse is significantly altered in background fields of the order of ~100 V/cm and higher. Practically, this means that air showers passing through thunderstorms emit radio pulses that are not a reliable measure for the shower energy. Under other weather circumstances significant electric field effects are expected to occur rarely, but nimbostratus clouds can harbor fields that are large enough. In general, the contribution of the electric field to the radio pulse ...

  16. Emission estimates for some acidifying and greenhouse gases and options for their control in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Pipatti, R. [VTT Energy, Espoo (Finland). Energy Systems

    1998-11-01

    This thesis presents estimates and options for control of anthropogenic ammonia (NH{sub 3}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O) and some halocarbon emissions in Finland. Ammonia is an air pollutant which contributes to both acidification and nitrogen eutrophication of ecosystems. Its emissions are mainly caused by livestock manure. In Finland the anthropogenic emissions of NH{sub 3} have been estimated to be approximately 44 Gg in 1985 and 43 Gg in 1990. In the 1990`s the emissions have declined due to the reduced number of cattle and voluntary implementation of emission reducing measures. The impact of NH{sub 3} emissions on acidification is serious but in Finland it is less than the impact of the other acidifying gases sulphur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}). All three gases and their transformation products are transported by the atmosphere up to distances of hundreds or even more than a thousand kilometres. NH{sub 3} emissions can be reduced with relatively cost-effective measures and the measures can partly replace the implementation of more costly abatement measures on SO{sub 2} and NO{sub x} emissions needed to lower the acidifying deposition in Finland. The other gases studied in this thesis are greenhouse gases. Some of the gases also deplete stratospheric ozone. Finnish anthropogenic CH{sub 4} emissions have been estimated to be around 250 Gg per year during the 1990`s. The emissions come mainly from landfills and agricultural sources (enteric fermentation and manure). The significance of other CH{sub 4} sources in Finland is minor. The potential to reduce the Finnish CH{sub 4} emissions is estimated to be good. Landfill gas recovery offers an option to reduce the emissions significantly at negligible cost if the energy produced can be utilised in electricity and/or heat production. Measures directed at reducing the emissions from livestock manure management are more costly, and the achievable reduction in the emissions

  17. First detection of Mars atmospheric hydroxyl: CRISM Near-IR measurement versus LMD GCM simulation of OH Meinel band emission in the Mars polar winter atmosphere

    Science.gov (United States)

    Todd Clancy, R.; Sandor, Brad J.; García-Muñoz, Antonio; Lefèvre, Franck; Smith, Michael D.; Wolff, Michael J.; Montmessin, Franck; Murchie, Scott L.; Nair, Hari

    2013-09-01

    Visible and near-IR Meinel band emissions originate from excited OH in the terrestrial upper atmosphere (Meinel, I.A.B. [1950]. Astrophys. J. 111, 555. http://dx.doi.org/10.1086/145296), and have recently been detected in the Venus nightside upper mesosphere (Piccioni, G. et al. [2008]. Astron. Astrophys. 483, L29-L33. http://dx.doi.org/10.1051/0004-6361:200809761). Meinel band observations support key studies of transport and photochemistry in both of these atmospheres. In the case of Mars, OH regulates the basic stability of the CO2 atmosphere to photolytic decomposition (to CO and O2, e.g. Parkinson, T.D., Hunten, D.M. [1972]. J. Atmos. Sci. 29, 1380-1390. http://dx.doi.org/10.1175/1520-0469(1972)0292.0.CO;2), and yet has never been measured. We present the first detection of Mars atmospheric OH, associated with CRISM near-IR spectral limb observations of polar night Meinel band emissions centered at 1.45 and 2.9 μm. Meinel band (1-0), (2-1), and (2-0) average limb intensities of 990 ± 280, 1060 ± 480, and 200 ± 100 kiloRayleighs (kR), respectively, are determined for 70-90 NS polar winter latitudes over altitudes of 40-56 km. Additional OH bands, such as (3-2), (3-1), and (4-2), present ⩽1σ measurements. Uncertainty in the (4-2) band emission rate contributes to increased uncertainty in the determination of the O2(1Δg) (0-0)/(0-1) band emission ratio A00/A01=47-12+26. An average profile retrieval for Mars OH polar nightglow indicates 45-55 km altitude levels for volume emission rates (VER) of 0.4 (2-0) to 2 (1-0, 2-1) × 104 photons/(cm3 s). Similar to polar night O2(1Δg) emission (e.g. Clancy, R.T. et al. [2012]. J. Geophys. Res. (Planets) 117, E00J10. http://dx.doi.org/10.1029/2011JE004018), Meinel OH band emission is supported by upper level, winter poleward transport of O and H in the deep Hadley solsticial circulations of Mars. The retrieved OH emission rates are compared to polar winter OH nightglow simulated by the LMD (Laboratoire de M

  18. On the Incorporation of Greenhouse Gases Emission into the Regulatory Scope of the Atmospheric Pollution Prevention and Control Law%《大气污染防治法》将温室气体 排放纳入控制体系的评析

    Institute of Scientific and Technical Information of China (English)

    赵俊; 孙宋龙

    2016-01-01

    对于温室气体控制是否应纳入《大气污染防治法》的调整范畴,一直都有争议. 不应将温室气体控制纳入《大气污染防治法》的调整范畴,这不仅是由于温室气体不属于大气污染物,也是由我国现阶段所处的国际和国内环境决定的. 温室气体主要来源于能源生产等"上游活动"和公众生活消费等"下游活动". 我们应对其进行上堵下疏:一方面力促清洁生产,另一方面倡导低碳生活,将市场机制与行政手段结合起来,多管齐下共同控制温室气体排放,没有必要将温室气体控制纳入《大气污染防治法》的调整范畴.%It has always been controversial whether or not to incorporate greenhouse gases control into the regulatory scope of Atmospheric Pollution Prevention and Control Law of the People' s Republic of China.Green-house gases control should not be incorporated into the regulatory scope of Atmospheric Pollution Prevention Law, not only because greenhouse gases do not belong to the atmospheric pollutants, but also as a result of Chi-na' s current international and domestic environment.Greenhouse gases are mainly derived from the upstream activities, e.g., energy production;and the downstream activities, e.g., public consumption, etc.We will stop the flow from the upstream and dredge the channel to the downstream by promoting cleaner energy produc-tion and advocating low-carbon life.Multi-pronged methods should be employed to control greenhouse gases by combining market mechanism with administrative means.Thus, there is no necessity to incorporate greenhouse gases control into the regulatory scope of Atmospheric Pollution Prevention Law.

  19. Storage of yerba maté in controlled atmosphere

    Directory of Open Access Journals (Sweden)

    Sarah Lemos Cogo Prestes

    2014-04-01

    Full Text Available The aim of this study was to evaluate the effect of controlled atmosphere in the change of color, chlorophyll degradation and phenolic compounds concentration in yerba maté thickly ground (“cancheada” and thinly milled (“socada”. Yerba maté samples from the towns of Arvorezinha (RS - Brazil and São Mateus do Sul (PR - Brazil were stored in four levels of oxygen (1, 3, 6 and 20.9kPa of O2 and four levels of carbon dioxide (0, 3, 6 and 18kPa of CO2 and then were analyzed, after nine months of storage. According to the results, the O2 partial pressure reduction decreased the loss of green coloration, kept a higher content of chlorophylls and of total phenolic compounds. In relation to the different levels of CO2, a response as remarkable as O2 was not observed. The yerba maté that was thickly ground (“cancheada” presented a better storage potential than the one thinly milled (“socada” in the storage with O2 and with CO2. The 1kPa of O2 condition kept the yerba maté greener and with a higher content of chlorophylls and of total phenolic compounds after nine months of storage. The CO2 partial pressure kept the yerba maté coloration greener and with a higher content of chlorophylls and of total phenolic compounds, regardless of the level used, in the maté from both cultivation areas.

  20. [Preservation of bread and pastry products in a controlled atmosphere].

    Science.gov (United States)

    Manchon, P

    1978-01-01

    Industrial soft pastries and the various breads are cereals products containing a humidity which is favorable to the development of mouldiness. Different or various methods of conservation has been attempted. One interesting approach to the problem is packaging in controlled atmosphere. It requires adequate machinery and suitable conditioning materials. Jardry-Buquet and Hayssen's machines are rapidly described as well as some of the packing film used for making air-tight bags. Bad results were observed with nitrogen, argon and a mixture of nitrogen-carbon dioxide. The satisfactory results obtained with the nitrous oxide for cakes (especially fruit-cakes) and for the bread with a mixture of ethylene oxide-carbon dioxide are: a good conservation for a period of 4 to 6 months in both cases. Organoleptic qualities of the products are not significantly diminished after eight weeks of preservation. The gases contained on the bags are analysed at different periods and the progressive disappearance of the nitrous oxide as well as the athylene dioxide was measured. The compounds derivated from these gases were researched on different extracts. No derivatives of the nitrous oxide were observed. From the ethylene oxide, the derivatives found in the bread are diethylene glycol and 2-chloroethanol; their concentrations are respectively 100 and 300 ppm in the case of 85 : 15 mixture, but decrease to a mere trace and 45 ppm in the case of 98 : 2 mixture. The measure of humidity, of peroxides and of the staleness of crumb are favourable for a good conservation. PMID:707931

  1. Fruit quality preservation of 'Laetitia' plums under controlled atmosphere storage

    Directory of Open Access Journals (Sweden)

    CRISTIANO ANDRÉ STEFFENS

    2014-03-01

    Full Text Available The objective of this study was to evaluate the effect of controlled atmosphere (CA on quality preservation of ‘Laetitia’ plums, mainly on internal breakdown, in order to determine the best CA storage conditions. Two experiments were carried out one in 2010, and another in 2011. In 2010, besides cold storage (CS; 21.0 kPa O2 + 0.03 kPa CO2, the fruits were stored under the following CA conditions (kPa O2+kPa CO2: 1+3, 1+5, 2+5, 2+10, and 11+10. In 2011, the fruits were stored under CS and CA of 1+0, 1+1, 2+1, and 2+2. The fruit stored under different CA conditions had lower respiration and ethylene production, better preservation of flesh firmness, texture and titratable acidity, lower skin red color, and lower incidence of skin cracking than the fruit in CS. In 2010, the fruit under CA with 2+5, 1+5, and 1+3 had a pronounced delay in ripening, although it exhibited a high incidence of internal breakdown. In 2011, the CA conditions with 2+1 and 2+2 provided the best delay in ripening and a reduced incidence of internal breakdown. The best CA condition for cold storage (at 0.5°C of ‘Laetitia’ plums is 2 kPa O2 + 2 kPa CO2.

  2. Control of mercury emissions: policies, technologies, and future trends

    OpenAIRE

    Rhee, Seung-Whee

    2015-01-01

    Seung-Whee Rhee Department of Environmental Engineering, Kyonggi University, Suwon, Republic of Korea Abstract: Owing to the Minamata Convention on Mercury and the Global Mercury Partnership, policies and regulations on mercury management in advanced countries were intensified by a mercury phaseout program in the mercury control strategy. In developing countries, the legislative or regulatory frameworks on mercury emissions are not established specifically, but mercury management is designed...

  3. Cost Functions for Controlling Ammonia Emissions in Europe

    OpenAIRE

    Klaassen, G.

    1990-01-01

    This paper presents a submodule which computes the costs of controlling ammonia emissions in 27 European countries. The submodule will be incorporated into the RAINS (Regional Acidification INformation and Simulation) model. Abatement options included are low nitrogen feed, stable adaptations, covering manure storage, biofiltration and low nitrogen applications of manure. Cost estimates are based on country-, animal-, and technology specific data such as the stable size and fertilizer price, ...

  4. Coal conversion control technology. Volume II. Gaseous emissions, solid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Bostwick, L.E.; Smith, M.R.; Moore, D.O.; Webber, D.K.

    1979-10-01

    Information has been gathered on coal conversion process streams. Available and developing control technology has been evaluated in view of the requirements of present and proposed federal, state, regional and international environmental standards. The study indicates that it appears possible to evolve technology to reduce each of the components of each process stream to an environmentally acceptable level. The conclusion has also been reached that such an approach would be costly and difficult of execution. Because all coal conversion processes are net users of water, liquid effluents need be treated only for recycling within the process, thus achieving essentially zero discharge. Further, with available technology gaseous emissions can be controlled to meet present environmental standards, particulates can be controlled or eliminated and disposal of solid wastes can be managed to avoid deleterious environmental effects. Volume I focuses on environmental regulations for gaseous, liquid, and solid wastes, and the control technology for liquid effluents. Volume II deals with the control technology of gaseous emissions and solid wastes. Volume III includes a program for economic analysis of control technology and includes the appendix.

  5. Nitrogen Availability Of Nitriding Atmosphere In Controlled Gas Nitriding Processes

    Directory of Open Access Journals (Sweden)

    Michalski J.

    2015-06-01

    Full Text Available Parameters which characterize the nitriding atmosphere in the gas nitriding process of steel are: the nitriding potential KN, ammonia dissociation rate α and nitrogen availabilitymN2. The article discusses the possibilities of utilization of the nitriding atmosphere’s nitrogen availability in the design of gas nitriding processes of alloyed steels in atmospheres derived from raw ammonia, raw ammonia diluted with pre-dissociated ammonia, with nitrogen, as well as with both nitrogen and pre-dissociated ammonia. The nitriding processes were accomplished in four series. The parameters selected in the particular processes were: process temperature (T, time (t, value of nitriding potential (KN, corresponding to known dissociation rate of the ammonia which dissociates during the nitriding process (α. Variable parameters were: nitrogen availability (mN2, composition of the ingoing atmosphere and flow rate of the ingoing atmosphere (FIn.

  6. Polar vortex controls coupling of North Atlantic Ocean and atmosphere

    OpenAIRE

    Graf, H; Walter, K.

    2005-01-01

    The structure of the North Atlantic leading atmospheric winter variability mode strongly depends on the state of the polar stratospheric vortex. If the polar vortex is strong, one teleconnection pattern emerges in the upper troposphere, while two mostly independent ones appear when the vortex is weak. The anomaly patterns associated with the different polarities of these modes show strong differences in the wind fields and in the correlation of atmospheric variability with the sea surface tem...

  7. Controlling automotive exhaust emissions: successes and underlying science.

    Science.gov (United States)

    Twigg, Martyn V

    2005-04-15

    Photochemical reactions of vehicle exhaust pollutants were responsible for photochemical smog in many cities during the 1960s and 1970s. Engine improvements helped, but additional measures were needed to achieve legislated emissions levels. First oxidation catalysts lowered hydrocarbon and carbon monoxide, and later nitrogen oxides were reduced to nitrogen in a two-stage process. By the 1980s, exhaust gas could be kept stoichiometric and hydrocarbons, carbon monoxide and nitrogen oxides were simultaneously converted over a single 'three-way catalyst'. Today, advanced three-way catalyst systems emissions are exceptionally low. NOx control from lean-burn engines demands an additional approach because NO cannot be dissociated under lean conditions. Current lean-burn gasoline engine NOx control involves forming a nitrate phase and periodically enriching the exhaust to reduce it to nitrogen, and this is being modified for use on diesel engines. Selective catalytic reduction with ammonia is an alternative that can be very efficient, but it requires ammonia or a compound from which it can be obtained. Diesel engines produce particulate matter, and, because of health concerns, filtration processes are being introduced to control these emissions. On heavy duty diesel engines the exhaust gas temperature is high enough for NO in the exhaust to be oxidised over a catalyst to NO2 that smoothly oxidises particulate material (PM) in the filter. Passenger cars operate at lower temperatures, and it is necessary to periodically burn the PM in air at high temperatures.

  8. A Review on Diesel Soot Emission, its Effect and Control

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-01-01

    Full Text Available The diesel engines are energy efficient, but their particulate (soot emissions are responsible of severe environmental and health problems. This review provides a survey on published information regarding diesel soot emission, its adverse effects on the human health, environment, vegetations, climate, etc. The legislations to limit diesel emissions and ways to minimize soot emission are also summarized. Soot particles are suspected to the development of cancer; cardiovascular and respiratory health effects; pollution of air, water, and soil; impact agriculture productivity, soiling of buildings; reductions in visibility; and global climate change. The review covers important recent developments on technologies for control of particulate matter (PM; diesel particulate filters (DPFs, summarizing new filter and catalyst materials and DPM measurement. DPF technology is in a state of optimization and cost reduction. New DPF regeneration strategies (active, passive and plasma-assisted regenerations as well as the new learning on the fundamentals of soot/catalyst interaction are described. Recent developments in diesel oxidation catalysts (DOC are also summarized showing potential issues with advanced combustion strategies, important interactions on NO2 formation, and new formulations for durability. Finally, systematic compilation of the concerned newer literature on catalytic oxidation of soot in a well conceivable tabular form is given. A total of 156 references are cited. ©2010 BCREC UNDIP. All rights reserved(Received: 2nd June 2010, Revised: 17th June 2010; Accepted: 24th June 2010[How to Cite: R. Prasad, V.R. Bella. (2010. Review on Diesel Soot Emission, its Effect and Control. Bulletin of Chemical Reaction Engineering and Catalysis, 5(2: 69-86. doi:10.9767/bcrec.5.2.794.69-86][DOI: http://dx.doi.org/10.9767/bcrec.5.2.794.69-86 || or local:   http://ejournal.undip.ac.id/index.php/bcrec/article/view/794 ]Cited by in: ACS 1 |

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

    Directory of Open Access Journals (Sweden)

    M. Karl

    2009-06-01

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

  10. Quantifying missing annual emission sources of heavy metals in the United Kingdom with an atmospheric transport model.

    Science.gov (United States)

    Dore, Anthony J; Hallsworth, Stephen; McDonald, Alan G; Werner, Małgorzata; Kryza, Maciej; Abbot, John; Nemitz, Eiko; Dore, Christopher J; Malcolm, Heath; Vieno, Massimo; Reis, Stefan; Fowler, David

    2014-05-01

    An atmospheric chemical transport model was adapted to simulate the concentration and deposition of heavy metals (arsenic, cadmium, chromium, copper, lead, nickel, selenium, vanadium, and zinc) in the United Kingdom. The model showed that wet deposition was the most important process for the transfer of metals from the atmosphere to the land surface. The model achieved a good correlation with annually averaged measurements of metal concentrations in air. The correlation with measurements of wet deposition was less strong due to the complexity of the atmospheric processes involved in the washout of particulate matter which were not fully captured by the model. The measured wet deposition and air concentration of heavy metals were significantly underestimated by the model for all metals (except vanadium) by factors between 2 and 10. These results suggest major missing sources of annual heavy metal emissions which are currently not included in the official inventory. Primary emissions were able to account for only 9%, 21%, 29%, 21%, 36%, 7% and 23% of the measured concentrations for As, Cd, Cr, Cu, Ni, Pb and Zn. A likely additional contribution to atmospheric heavy metal concentrations is the wind driven re-suspension of surface dust still present in the environment from the legacy of much higher historic emissions. Inclusion of two independent estimates of emissions from re-suspension in the model was found to give an improved agreement with measurements. However, an accurate estimate of the magnitude of re-suspended emissions is restricted by the lack of measurements of metal concentrations in the re-suspended surface dust layer.

  11. Exploring the control of land-atmospheric oscillations over terrestrial vegetation productivity

    Science.gov (United States)

    Depoorter, Mathieu; Green, Julia; Gentine, Pierre; Liu, Yi; van Eck, Christel; Regnier, Pierre; Dorigo, Wouter; Verhoest, Niko; Miralles, Diego

    2015-04-01

    Vegetation dynamics play an important role in the climate system due to their control on the carbon, energy and water cycles. The spatiotemporal variability of vegetation is regulated by internal climate variability as well as natural and anthropogenic forcing mechanisms, including fires, land use, volcano eruptions or greenhouse gas emissions. Ocean-atmospheric oscillations, affect the fluxes of heat and water over continents, leading to anomalies in radiation, precipitation or temperature at widely separated locations (i.e. teleconnections); an effect of ocean-atmospheric oscillations on terrestrial primary productivity can therefore be expected. While different studies have shown the general importance of internal climate variability for global vegetation dynamics, the control by particular teleconnections over the regional growth and decay of vegetation is still poorly understood. At continental to global scales, satellite remote sensing offers a feasible approach to enhance our understanding of the main drivers of vegetation variability. Traditional studies of the multi-decadal variability of global vegetation have been usually based on the normalized difference vegetation index (NDVI) derived from the Advanced Very High Resolution Radiometer (AVHRR), which extends back to the early '80s. There are, however, some limitations to NDVI observations; arguably the most important of these limitations is that from the plant physiology perspective the index does not have a well-defined meaning, appearing poorly correlated to vegetation productivity. On the other hand, recently developed records from other remotely-sensed properties of vegetation, like fluorescence or microwave vegetation optical depth, have proven a significantly better correspondence to above-ground biomass. To enhance our understanding of the controls of ocean-atmosphere oscillations over vegetation, we propose to explore the link between climate oscillation extremes and net primary productivity

  12. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Science.gov (United States)

    2010-07-01

    ... Determination of equivalent emission control technology. (a) Any person requesting that the use of certain... equivalent emission reductions: (1) Diagrams, as appropriate, illustrating the emission control technology...) during each portion of the dry cleaning cycle with and without the use of the candidate emission...

  13. 49 CFR 195.583 - What must I do to monitor atmospheric corrosion control?

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false What must I do to monitor atmospheric corrosion... SAFETY TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Corrosion Control § 195.583 What must I do to monitor atmospheric corrosion control? (a) You must inspect each pipeline or portion of pipeline that...

  14. Control of the Diurnal Pattern of Methane Emission from Emergent Aquatic Macrophytes by Gas Transport Mechanisms

    Science.gov (United States)

    Whiting, Gary J.; Chanton, Jeffrey P.

    1995-01-01

    Methane emissions from Typha latifolia (L.) showed a large mid-morning transient peak associated with rising light levels. This peak was also associated with a steep decline in lacunal CH, concentrations near the stem base. This pattern contrasted sharply with emissions from Peltandra virginica (L.) that gradually rose to a peak in the mid-afternoon corresponding to elevated air temperatures. Internal CH4 concentrations within P. virginica stems did not change significantly over the diurnal period. Stomatal conductance appeared to correlate directly with light levels in both plant types and were not associated with peak CH4 emission events in either plant. These patterns are consistent with a convective throughflow and diffusive gas ventilation systems for Typha and Peltandra, respectively. Further effects of the convective throughflow in T. latifolia were evident in the elevated CH4 concentrations measured within brown leaves as contrasted to the near ambient levels measured within live green leaves. Experimental manipulation of elevated and reduced CO2 levels in the atmosphere surrounding the plants and of light/dark periods suggested that stomatal aperture has little or no control of methane emissions from T. latifolia.

  15. Atmospheric observation-based global SF6 emissions – comparison of top-down and bottom-up estimates

    Directory of Open Access Journals (Sweden)

    D. E. Worthy

    2009-12-01

    Full Text Available Emissions of sulphur hexafluoride (SF6, one of the strongest greenhouse gases on a per molecule basis, are targeted to be collectively reduced under the Kyoto Protocol. Because of its long atmospheric lifetime (≈3000 years, the accumulation of SF6 in the atmosphere is a direct measure of its global emissions. Examination of our extended data set of globally distributed high-precision SF6 observations shows an increase in SF6 abundance from near zero in the 1970s to a global mean of 6.7 ppt by the end of 2008. In-depth evaluation of our long-term data records shows that the global source of SF6 decreased after 1995, most likely due to SF6 emission reductions in industrialised countries, but increased again after 1998. By subtracting those emissions reported by Annex I countries to the United Nations Framework Convention of Climatic Change (UNFCCC from our observation-inferred SF6 source leaves a surprisingly large gap of more than 70–80% of non-reported SF6 emissions in the last decade.

  16. Land Surface Microwave Emissivities Derived from AMSR-E and MODIS Measurements with Advanced Quality Control

    Science.gov (United States)

    Moncet, Jean-Luc; Liang, Pan; Galantowicz, John F.; Lipton, Alan E.; Uymin, Gennady; Prigent, Catherine; Grassotti, Christopher

    2011-01-01

    A microwave emissivity database has been developed with data from the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and with ancillary land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the same Aqua spacecraft. The primary intended application of the database is to provide surface emissivity constraints in atmospheric and surface property retrieval or assimilation. An additional application is to serve as a dynamic indicator of land surface properties relevant to climate change monitoring. The precision of the emissivity data is estimated to be significantly better than in prior databases from other sensors due to the precise collocation with high-quality MODIS LST data and due to the quality control features of our data analysis system. The accuracy of the emissivities in deserts and semi-arid regions is enhanced by applying, in those regions, a version of the emissivity retrieval algorithm that accounts for the penetration of microwave radiation through dry soil with diurnally varying vertical temperature gradients. These results suggest that this penetration effect is more widespread and more significant to interpretation of passive microwave measurements than had been previously established. Emissivity coverage in areas where persistent cloudiness interferes with the availability of MODIS LST data is achieved using a classification-based method to spread emissivity data from less-cloudy areas that have similar microwave surface properties. Evaluations and analyses of the emissivity products over homogeneous snow-free areas are presented, including application to retrieval of soil temperature profiles. Spatial inhomogeneities are the largest in the vicinity of large water bodies due to the large water/land emissivity contrast and give rise to large apparent temporal variability in the retrieved emissivities when satellite footprint locations vary over time. This issue will be dealt with in the future by

  17. Oxidation Products of Biogenic Emissions Contribute to Nucleation of Atmospheric Particles

    OpenAIRE

    Riccobono, F.; Schobesberger, S.; Scott, CE; Dommen, J; Ortega, IK; L. Rondo; Almeida, J; Amorim, A.; BIANCHI, F.; Breitenlechner, M.; David, A.(CERN, European Organization for Nuclear Research, Geneva, Switzerland); Downard, A.; Dunne, EM; J. Duplissy; S. Ehrhart

    2014-01-01

    Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in ...

  18. HEMCO v1.0: A versatile, ESMF-compliant component for calculating emissions in atmospheric models

    Directory of Open Access Journals (Sweden)

    C. A. Keller

    2014-01-01

    Full Text Available We describe the Harvard-NASA Emission Component version 1.0 (HEMCO, a stand-alone software component for computing emissions in global atmospheric models. HEMCO determines emissions from different sources, regions and species on a user-specified grid and can combine, overlay, and update a set of data inventories and scale factors, selected by the user from a data library through the HEMCO configuration file. New emission inventories at any spatial and temporal resolution are readily added to HEMCO and can be accessed by the user without any pre-processing of the data files or modification of the source code. Emissions that depend on dynamic source types and local environmental variables such as wind speed or surface temperature are calculated in separate HEMCO extensions. HEMCO is fully compliant with the Earth System Modeling Framework (ESMF environment. It is highly portable and can be deployed in a new model environment with only few adjustments at the top-level interface. So far, we have implemented HEMCO in the NASA GEOS-5 Earth System Model (ESM and in the GEOS-Chem chemical transport model (CTM. By providing a widely applicable framework for specifying constituent emissions, HEMCO is designed to ease sensitivity studies and model comparisons, as well as inverse modeling in which emissions are adjusted iteratively. The HEMCO code, extensions, and data libraries are available at http://wiki.geos-chem.org/HEMCO.

  19. Atmospheric CO2: principal control knob governing Earth's temperature.

    Science.gov (United States)

    Lacis, Andrew A; Schmidt, Gavin A; Rind, David; Ruedy, Reto A

    2010-10-15

    Ample physical evidence shows that carbon dioxide (CO(2)) is the single most important climate-relevant greenhouse gas in Earth's atmosphere. This is because CO(2), like ozone, N(2)O, CH(4), and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO(2) and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state. PMID:20947761

  20. Active Control of Combustor Instability Shown to Help Lower Emissions

    Science.gov (United States)

    DeLaat, John C.; Chang, Clarence T.

    2002-01-01

    In a quest to reduce the environmental impact of aerospace propulsion systems, extensive research is being done in the development of lean-burning (low fuel-to-air ratio) combustors that can reduce emissions throughout the mission cycle. However, these lean-burning combustors have an increased susceptibility to thermoacoustic instabilities, or high-pressure oscillations much like sound waves, that can cause severe high-frequency vibrations in the combustor. These pressure waves can fatigue the combustor components and even the downstream turbine blades. This can significantly decrease the safe operating life of the combustor and turbine. Thus, suppression of the thermoacoustic combustor instabilities is an enabling technology for lean, low-emissions combustors. Under the Aerospace Propulsion and Power Base Research and Technology Program, the NASA Glenn Research Center, in partnership with Pratt & Whitney and United Technologies Research Center, is developing technologies for the active control of combustion instabilities. With active combustion control, the fuel is pulsed to put pressure oscillations into the system. This cancels out the pressure oscillations being produced by the instabilities. Thus, the engine can have lower pollutant emissions and long life.The use of active combustion instability control to reduce thermo-acoustic-driven combustor pressure oscillations was demonstrated on a single-nozzle combustor rig at United Technologies. This rig has many of the complexities of a real engine combustor (i.e., an actual fuel nozzle and swirler, dilution cooling, etc.). Control was demonstrated through modeling, developing, and testing a fuel-delivery system able to the 280-Hz instability frequency. The preceding figure shows the capability of this system to provide high-frequency fuel modulations. Because of the high-shear contrarotating airflow in the fuel injector, there was some concern that the fuel pulses would be attenuated to the point where they would

  1. A multiresolution spatial parametrization for the estimation of fossil-fuel carbon dioxide emissions via atmospheric inversions.

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Jaideep; Lee, Jina; Lefantzi, Sophia; Yadav, Vineet [Carnegie Institution for Science, Stanford, CA; Michalak, Anna M. [Carnegie Institution for Science, Stanford, CA; van Bloemen Waanders, Bart Gustaaf [Sandia National Laboratories, Albuquerque, NM; McKenna, Sean Andrew [IBM Research, Mulhuddart, Dublin 15, Ireland

    2013-04-01

    The estimation of fossil-fuel CO2 emissions (ffCO2) from limited ground-based and satellite measurements of CO2 concentrations will form a key component of the monitoring of treaties aimed at the abatement of greenhouse gas emissions. To that end, we construct a multiresolution spatial parametrization for fossil-fuel CO2 emissions (ffCO2), to be used in atmospheric inversions. Such a parametrization does not currently exist. The parametrization uses wavelets to accurately capture the multiscale, nonstationary nature of ffCO2 emissions and employs proxies of human habitation, e.g., images of lights at night and maps of built-up areas to reduce the dimensionality of the multiresolution parametrization. The parametrization is used in a synthetic data inversion to test its suitability for use in atmospheric inverse problem. This linear inverse problem is predicated on observations of ffCO2 concentrations collected at measurement towers. We adapt a convex optimization technique, commonly used in the reconstruction of compressively sensed images, to perform sparse reconstruction of the time-variant ffCO2 emission field. We also borrow concepts from compressive sensing to impose boundary conditions i.e., to limit ffCO2 emissions within an irregularly shaped region (the United States, in our case). We find that the optimization algorithm performs a data-driven sparsification of the spatial parametrization and retains only of those wavelets whose weights could be estimated from the observations. Further, our method for the imposition of boundary conditions leads to a 10computational saving over conventional means of doing so. We conclude with a discussion of the accuracy of the estimated emissions and the suitability of the spatial parametrization for use in inverse problems with a significant degree of regularization.

  2. Muscodor albus Volatiles Control Toxigenic Fungi under Controlled Atmosphere (CA Storage Conditions

    Directory of Open Access Journals (Sweden)

    Gordon Braun

    2012-11-01

    Full Text Available Muscodor albus, a biofumigant fungus, has the potential to control post-harvest pathogens in storage. It has been shown to produce over 20 volatile compounds with fungicidal, bactericidal and insecticidal properties. However, M. albus is a warm climate endophyte, and its biofumigant activity is significantly inhibited at temperatures below 5 °C. Conidia of seven mycotoxin producing fungi, Aspergillus carbonarius, A. flavus, A. niger, A. ochraceus, Penicillium verrucosum, Fusarium culmorum and F. graminearum, were killed or prevented from germinating by exposure to volatiles from 2 g M. albus-colonized rye grain per L of headspace in sealed glass jars for 24 h at 20 °C. Two major volatiles of M. albus, isobutyric acid (IBA and 2-methyl-1-butanol (2MB at 50 µL/L and 100 µL/L, respectively, gave differential control of the seven fungi when applied individually at 20 °C. When the fungi were exposed to both IBA and 2MB together, an average of 94% of the conidia were killed or suppressed. In a factorial experiment with controlled atmosphere storage (CA at 3 °C and 72 h exposure to four concentrations of IBA and 2MB combinations, 50 µL/L IBA plus 100 µL/L 2MB killed or suppressed germination of the conidia of all seven fungi. Controlled atmosphere had no significant effect on conidial viability or volatile efficacy. Major volatiles of M. albus may have significant potential to control plant pathogens in either ambient air or CA storage at temperatures below 5 °C. However, combinations of volatiles may be required to provide a broader spectrum of control than individual volatiles.

  3. Optimal capture and sequestration from the carbon emission flow and from the atmospheric carbon stock with heterogeneous energy consuming sectors

    OpenAIRE

    Amigues, Jean-Pierre; Lafforgue, Gilles; MOREAUX Michel

    2010-01-01

    We characterize the optimal exploitation paths of two primary energy resources. The first one is a non-renewable polluting resource, the second one a pollution-free renewable resource. Both resources can supply the energy needs of two sectors. Sector 1 is able to reduce the potential carbon emissions generated by its non-renewable energy consumption at a reasonable cost while sector 2 cannot. Another possibility is to capture the carbon spread in the atmosphere but at a significantly higher c...

  4. Catalysts under Controlled Atmospheres in the Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2014-01-01

    microscope, and since its invention by Ernst Ruska, the idea of imaging samples under gaseous atmospheres was envisioned. However, microscopes have traditionally been operated in high vacuum due to sensitive electron sources, sample contamination, and electron scattering off gas molecules resulting in loss...

  5. 49 CFR 192.481 - Atmospheric corrosion control: Monitoring.

    Science.gov (United States)

    2010-10-01

    ... calendar years, but with intervals not exceeding 39 months Offshore At least once each calendar year, but... attention to pipe at soil-to-air interfaces, under thermal insulation, under disbonded coatings, at pipe supports, in splash zones, at deck penetrations, and in spans over water. (c) If atmospheric corrosion...

  6. External costs of atmospheric Pb emissions: valuation of neurotoxic impacts due to inhalation

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Thomsen, Marianne; Frohn, Lise;

    2010-01-01

    The Impact Pathway Approach (IPA) is an innovative methodology to establish links between emissions, related impacts and monetary estimates. Only few attempts have so far been presented regarding emissions of metals; in this study the external costs of airborne lead (Pb) emissions are assessed us...

  7. U.S. regional greenhouse gas emissions analysis comparing highly resolved vehicle miles traveled and CO2 emissions: mitigation implications and their effect on atmospheric measurements

    Science.gov (United States)

    Mendoza, D. L.; Gurney, K. R.

    2010-12-01

    Carbon dioxide (CO2) is the most abundant anthropogenic greenhouse gas and projections of fossil fuel energy demand show CO2 concentrations increasing indefinitely into the future. After electricity production, the transportation sector is the second largest CO2 emitting economic sector in the United States, accounting for 32.3% of the total U.S. emissions in 2002. Over 80% of the transport sector is composed of onroad emissions, with the remainder shared by the nonroad, aircraft, railroad, and commercial marine vessel transportation. In order to construct effective mitigation policy for the onroad transportation sector and more accurately predict CO2 emissions for use in transport models and atmospheric measurements, analysis must incorporate the three components that determine the CO2 onroad transport emissions: vehicle fleet composition, average speed of travel, and emissions regulation strategies. Studies to date, however, have either focused on one of these three components, have been only completed at the national scale, or have not explicitly represented CO2 emissions instead relying on the use of vehicle miles traveled (VMT) as an emissions proxy. National-level projections of VMT growth is not sufficient to highlight regional differences in CO2 emissions growth due to the heterogeneity of vehicle fleet and each state’s road network which determines the speed of travel of vehicles. We examine how an analysis based on direct CO2 emissions and an analysis based on VMT differ in terms of their emissions and mitigation implications highlighting potential biases introduced by the VMT-based approach. This analysis is performed at the US state level and results are disaggregated by road and vehicle classification. We utilize the results of the Vulcan fossil fuel CO2 emissions inventory which quantified emissions for the year 2002 across all economic sectors in the US at high resolution. We perform this comparison by fuel type,12 road types, and 12 vehicle types

  8. Record high peaks in PCB concentrations in the Arctic atmosphere due to long-range transport of biomass burning emissions

    Directory of Open Access Journals (Sweden)

    S. Eckhardt

    2007-05-01

    Full Text Available Soils and forests in the boreal region of the northern hemisphere are recognised as having a large capacity for storing air-borne Persistent Organic Pollutants (POPs, such as the polychlorinated biphenyls (PCBs. Following reductions of primary emissions of various legacy POPs, there is an increasing interest and debate about the relative importance of secondary re-emissions on the atmospheric levels of POPs. In spring of 2006, biomass burning emissions from agricultural fires in Eastern Europe were transported to the Zeppelin station on Svalbard, where record-high levels of many air pollutants were recorded (Stohl et al., 2007. Here we report on the extremely high concentrations of PCBs that were also measured during this period. 21 out of 32 PCB congeners were enhanced by more than two standard deviations above the long-term mean concentrations. In July 2004, about 5.8 million hectare of boreal forest burned in North America, emitting a pollution plume which reached the Zeppelin station after a travel time of 3–4 weeks (Stohl et al., 2006. Again, 12 PCB congeners were elevated above the long-term mean by more than two standard deviations, with the less chlorinated congeners being most strongly affected. We propose that these abnormally high concentrations were caused by biomass burning emissions. Based on enhancement ratios with carbon monoxide and known emissions factors for this species, we estimate that 130 and 66 μg PCBs were released per kilogram dry matter burned, respectively. To our knowledge, this is the first study relating atmospheric PCB enhancements with biomass burning. The strong effects on observed concentrations far away from the sources, suggest that biomass burning is an important source of PCBs for the atmosphere.

  9. Record high peaks in PCB concentrations in the Arctic atmosphere due to long-range transport of biomass burning emissions

    Directory of Open Access Journals (Sweden)

    S. Eckhardt

    2007-08-01

    Full Text Available Soils and forests in the boreal region of the Northern Hemisphere are recognised as having a large capacity for storing air-borne Persistent Organic Pollutants (POPs, such as the polychlorinated biphenyls (PCBs. Following reductions of primary emissions of various legacy POPs, there is an increasing interest and debate about the relative importance of secondary re-emissions on the atmospheric levels of POPs. In spring of 2006, biomass burning emissions from agricultural fires in Eastern Europe were transported to the Zeppelin station on Svalbard, where record-high levels of many air pollutants were recorded (Stohl et al., 2007. Here we report on the extremely high concentrations of PCBs that were also measured during this period. 21 out of 32 PCB congeners were enhanced by more than two standard deviations above the long-term mean concentrations. In July 2004, about 5.8 million hectare of boreal forest burned in North America, emitting a pollution plume which reached the Zeppelin station after a travel time of 3–4 weeks (Stohl et al., 2006. Again, 12 PCB congeners were elevated above the long-term mean by more than two standard deviations, with the less chlorinated congeners being most strongly affected. We propose that these abnormally high concentrations were caused by biomass burning emissions. Based on enhancement ratios with carbon monoxide and known emissions factors for this species, we estimate that 130 and 66 μg PCBs were released per kilogram dry matter burned, respectively. To our knowledge, this is the first study relating atmospheric PCB enhancements with biomass burning. The strong effects on observed concentrations far away from the sources, suggest that biomass burning is an important source of PCBs for the atmosphere.

  10. CO2 and CO emission rates from three forest fire controlled experiments in Western Amazonia

    Science.gov (United States)

    Carvalho, J. A., Jr.; Amaral, S. S.; Costa, M. A. M.; Soares Neto, T. G.; Veras, C. A. G.; Costa, F. S.; van Leeuwen, T. T.; Krieger Filho, G. C.; Tourigny, E.; Forti, M. C.; Fostier, A. H.; Siqueira, M. B.; Santos, J. C.; Lima, B. A.; Cascão, P.; Ortega, G.; Frade, E. F., Jr.

    2016-06-01

    Forests represent an important role in the control of atmospheric emissions through carbon capture. However, in forest fires, the carbon stored during photosynthesis is released into the atmosphere. The carbon quantification, in forest burning, is important for the development of measures for its control. The aim of this study was to quantify CO2 and CO emissions of forest fires in Western Amazonia. In this paper, results are described of forest fire experiments conducted in Cruzeiro do Sul and Rio Branco, state of Acre, and Candeias do Jamari, state of Rondônia, Brazil. These cities are located in the Western portion of the Brazilian Amazon region. The biomass content per hectare, in the virgin forest, was measured by indirect methods using formulas with parameters of forest inventories in the central hectare of the test site. The combustion completeness was estimated by randomly selecting 10% of the total logs and twelve 2 × 2 m2 areas along three transects and examining their consumption rates by the fire. The logs were used to determine the combustion completeness of the larger materials (characteristic diameters larger than 10 cm) and the 2 × 2 m2 areas to determine the combustion completeness of small-size materials (those with characteristic diameters lower than 10 cm) and the. The overall biomass consumption by fire was estimated to be 40.0%, 41.2% and 26.2%, in Cruzeiro do Sul, Rio Branco and Candeias do Jamari, respectively. Considering that the combustion gases of carbon in open fires contain approximately 90.0% of CO2 and 10.0% of CO in volumetric basis, the average emission rates of these gases by the burning process, in the three sites, were estimated as 191 ± 46.7 t ha-1 and 13.5 ± 3.3 t ha-1, respectively.

  11. 40 CFR 1060.104 - What running loss emission control requirements apply?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What running loss emission control requirements apply? 1060.104 Section 1060.104 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EVAPORATIVE EMISSIONS FROM NEW AND IN-USE NONROAD AND STATIONARY EQUIPMENT Emission Standards...

  12. 40 CFR 75.34 - Units with add-on emission controls.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Units with add-on emission controls... add-on emission controls. (a) The owner or operator of an affected unit equipped with add-on SO2 and... which the add-on emission controls are documented to be operating properly, as described in the...

  13. A CRIRES-search for H3+ emission from the hot Jupiter atmosphere of HD 209458 b

    CERN Document Server

    Lenz, Lea; Seifahrt, Andreas; Kaeufl, Hans-Ulrich

    2016-01-01

    Close-in extrasolar giant planets are expected to cool their thermospheres by producing H3+ emission in the near-infrared (NIR), but simulations predict H3+ emission intensities that differ in the resulting intensity by several orders of magnitude. We want to test the observability of H3+ emission with CRIRES at the Very Large Telescope (VLT), providing adequate spectral resolution for planetary atmospheric lines in NIR spectra. We search for signatures of planetary H3+ emission in the L` band, using spectra of HD 209458 obtained during and after secondary eclipse of its transiting planet HD 209458 b. We searched for H3+ emission signatures in spectra containing the combined light of the star and, possibly, the planet. With the information on the ephemeris of the transiting planet, we derive the radial velocities at the time of observation and search for the emission at the expected line positions and search for planetary signals and use a shift and add technique combining all observed spectra taken after sec...

  14. Method of electron emission control in RF guns

    International Nuclear Information System (INIS)

    The electron emission control method for a RF gun is considered.According to the main idea of the method,the additional resonance system is created in a cathode region where the RF field strength could be varied using the external pulse equipment. The additional resonance system is composed of a coaxial cavity coupled with a RF gun cylindrical cavity via an axial hole. Computed results of radiofrequency and electrodynamic performances of such a two-cavity system and results of the RF gun model pilot study are presented in. Results of particle dynamics simulation are described

  15. Method of electron emission control in RF guns

    CERN Document Server

    Khodak, I V

    2001-01-01

    The electron emission control method for a RF gun is considered.According to the main idea of the method,the additional resonance system is created in a cathode region where the RF field strength could be varied using the external pulse equipment. The additional resonance system is composed of a coaxial cavity coupled with a RF gun cylindrical cavity via an axial hole. Computed results of radiofrequency and electrodynamic performances of such a two-cavity system and results of the RF gun model pilot study are presented in. Results of particle dynamics simulation are described.

  16. Jovian longitudinal control of Io-related radio emissions

    Science.gov (United States)

    Dessler, A. J.; Hill, T. W.

    1979-01-01

    A theoretical model is proposed to explain the control of Io-related radio emissions by Jupiter's rotational phase. The model is based on the hypothesis that the radio emissions are generated by Birkeland currents flowing between Io and the Jovian ionosphere. Specifically, it is suggested that the precipitation of radiation-belt electrons within a certain range of Jovian longitudes produces a restricted region of enhanced ionization and correspondingly enhanced conductivity in Jupiter's ionosphere and that the Io-Jupiter Birkeland current and the associated radio emissions are dramatically increased when Io's flux tube encounters this sector of enhanced ionization in Jupiter's ionosphere. The magnitude of the current is found to be about 100,000 A at most Jovian longitudes because of ionospheric resistance. It is estimated that within the favored longitudinal sector electron precipitation produces an enhancement of this current by one to three orders of magnitude. The model predictions are compared with observations made during the Pioneer 10 and 11 flybys, and satisfactory agreement is obtained.

  17. A multi-scale approach to monitor urban carbon-dioxide emissions in the atmosphere over Vancouver, Canada

    Science.gov (United States)

    Christen, A.; Crawford, B.; Ketler, R.; Lee, J. K.; McKendry, I. G.; Nesic, Z.; Caitlin, S.

    2015-12-01

    Measurements of long-lived greenhouse gases in the urban atmosphere are potentially useful to constrain and validate urban emission inventories, or space-borne remote-sensing products. We summarize and compare three different approaches, operating at different scales, that directly or indirectly identify, attribute and quantify emissions (and uptake) of carbon dioxide (CO2) in urban environments. All three approaches are illustrated using in-situ measurements in the atmosphere in and over Vancouver, Canada. Mobile sensing may be a promising way to quantify and map CO2 mixing ratios at fine scales across heterogenous and complex urban environments. We developed a system for monitoring CO2 mixing ratios at street level using a network of mobile CO2 sensors deployable on vehicles and bikes. A total of 5 prototype sensors were built and simultaneously used in a measurement campaign across a range of urban land use types and densities within a short time frame (3 hours). The dataset is used to aid in fine scale emission mapping in combination with simultaneous tower-based flux measurements. Overall, calculated CO2 emissions are realistic when compared against a spatially disaggregated scale emission inventory. The second approach is based on mass flux measurements of CO2 using a tower-based eddy covariance (EC) system. We present a continuous 7-year long dataset of CO2 fluxes measured by EC at the 28m tall flux tower 'Vancouver-Sunset'. We show how this dataset can be combined with turbulent source area models to quantify and partition different emission processes at the neighborhood-scale. The long-term EC measurements are within 10% of a spatially disaggregated scale emission inventory. Thirdly, at the urban scale, we present a dataset of CO2 mixing ratios measured using a tethered balloon system in the urban boundary layer above Vancouver. Using a simple box model, net city-scale CO2 emissions can be determined using measured rate of change of CO2 mixing ratios

  18. Fermi large area telescope observations of the cosmic-ray induced γ-ray emission of the Earth's atmosphere<