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1

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2  

NASA Astrophysics Data System (ADS)

Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs) emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2-C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenates, halocarbons, and sulphur compounds) in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Methane, CO, CO2, NO, NO2, NOy, SO2 and 53 VOCs (e.g., halocarbons, sulphur species, NMHCs) showed clear statistical enhancements (up to 1.1-397×) over the oil sands compared to local background values and, with the exception of CO, were higher over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species) either were not enhanced or were minimally enhanced (< 10%) over the oil sands. Ozone levels remained low because of titration by NO, and three VOCs (propyne, furan, MTBE) remained below their 3 pptv detection limit throughout the flight. Based on their mutual correlations, the compounds emitted by the oil sands industry fell into two groups: (1) evaporative emissions from the oil sands and its products and/or from the diluent used to lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2-C4 alkanes, C2-C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b). Prominent in the second group, SO2 and NO were remarkably enhanced over the oil sands, with maximum enhancements of 38.7 and 5.0 ppbv, or 383 and 319× the local background, respectively. The SO2 enhancements are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4 ethane and propane suggest low natural gas leakage despite its heavy use at the surface mining sites. In addition to the emission of many trace gases, the natural drawdown of OCS by vegetation was absent above the surface mining operations, presumably because of the widespread land disturbance. Unexpectedly, the mixing ratios of ?- and ?-pinene were much higher over the oil sands (up to 217 and 610 pptv, respectively) than over vegetation in the background boundary layer (20±7 and 84±24 pptv, respectively), and the pinenes correlated well with several industrial tracers that were elevated in the oil sands plumes. Because so few independent measurements from the oil sands mining industry exist, this study provides an important initial characterization of trace gas emissions from oil sands surface mining operations.

Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

2010-08-01

2

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2  

NASA Astrophysics Data System (ADS)

Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs) emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2-C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenated hydrocarbons, halocarbons and sulphur compounds) in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Carbon dioxide, CH4, CO, NO, NO2, NOy, SO2 and 53 VOCs (e.g., non-methane hydrocarbons, halocarbons, sulphur species) showed clear statistical enhancements (1.1-397×) over the oil sands compared to local background values and, with the exception of CO, were greater over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species) either were not enhanced or were minimally enhanced (<10%) over the oil sands. Ozone levels remained low because of titration by NO, and three VOCs (propyne, furan, MTBE) remained below their 3 pptv detection limit throughout the flight. Based on their correlations with one another, the compounds emitted by the oil sands industry fell into two groups: (1) evaporative emissions from the oil sands and its products and/or from the diluent used to lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort, such as upgraders (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2-C4 alkanes, C2-C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b). Prominent in the second group, SO2 and NO were remarkably enhanced over the oil sands, with maximum mixing ratios of 38.7 ppbv and 5.0 ppbv, or 383× and 319× the local background, respectively. These SO2 levels are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4, ethane and propane suggest low levels of natural gas leakage despite its heavy use at the surface mining sites. Instead the elevated CH4 levels are attributed to methanogenic tailings pond emissions. In addition to the emission of many trace gases, the natural drawdown of OCS by vegetation was absent above the surface mining operations, presumably because of the widespread land disturbance. Unexpectedly, the mixing ratios of ?-pinene and ?-pinene were much greater over the oil sands (up to 217 pptv and 610 pptv, respectively) than over vegetation in the background boundary layer (20±7 pptv and 84±24 pptv, respectively), and the pinenes correlated well with several industrial tracers that were elevated in the oil sands plumes. Because so few independent measurements from the oil sands mining industry exist, this study provides an important initial characterization of trace gas emissions from oil sands surface mining operations.

Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

2010-12-01

3

Next-Generation Aura/OMI NO2 and SO2 Products  

NASA Technical Reports Server (NTRS)

The measurement of both SO2 and NO2 gases are recognized as an essential component of atmospheric composition missions. We describe current capabilities and limitations of the operational Aura/OMI NO2 and SO2 data that have been used by a large number of researchers. Analyses of the data and validation studies have brought to light a number of areas in which these products can be expanded and improved. Major improvements for new NASA standard (SP) NO2 product include more accurate tropospheric and stratospheric column amounts, along with much improved error estimates and diagnostics. Our approach uses a monthly NO2 climatology based on the NASA Global Modeling Initiative (GMI) chemistry-transport model and takes advantage of OMI data from cloudy scenes to find clean areas where the contribution from the trap NO2 column is relatively small. We then use a new filtering, interpolation and smoothing techniques for separating the stratospheric and tropospheric components of NO2, minimizing the influence of a priori information. The new algorithm greatly improves the structure of stratospheric features relative to the original SP. For the next-generation OMI SO2 product we plan to implement operationally the offline iterative spectral fitting (ISF) algorithm and re-process the OMI Level-2 SO2 dataset using a priori SO2 and aerosol profiles, clouds, and surface reflectivity appropriate for observation conditions. This will improve the ability to detect and quantify weak tropospheric SO2 loadings. The new algorithm is validated using aircraft in-situ data during field campaigns in China (2005 and 2008) and in Maryland (Frostburg, 2010 and DISCOVER-AQ in July 2011). The height of the SO2 plumes will also be estimated for high SO2 loading cases (e.g., volcanic eruptions). The same SO2 algorithm will be applied to the data from OMPS sensor to be launched on NPP satellite later this year. The next-generation NO2 and SO2 products will provide critical information (e.g., averaging kernels) for evaluation of chemistry-transport models, for data assimilation, and to impose top-down constraints on the SO2 and NO2 emission sources.

Krotkov, Nickolay; Yang, Kai; Bucsela, Eric; Lamsal, Lok; Celarier, Edward; Swartz, William; Carn, Simon; Bhartia, Pawan; Gleason, James; Pickering, Ken; Dickerson, Russ

2011-01-01

4

SO2 and NO2 over major urban regions of India: a tempo-spatial perspective  

NASA Astrophysics Data System (ADS)

Demographic projections show that by the year 2025, 16 of the world's 29 megacities will be located in Asia, many of which have very basic problems in terms of air quality. Apart from being home to a burgeoning population, these regions of the globe are also major players in atmospheric chemistry as a result of myriad emission patterns combined with intense photochemistry. Like most of these Asian megacities, fast-paced development in some of the Indian cities has ramifications in increased emissions from industrial and transport sectors. These emissions release sulfur dioxide (SO2) and nitrogen dioxide (NO2), in addition to several pollutants, into the ambient air and have the potential to impact the chemistry and radiative balance on a regional scale. Surface measurements of these two criteria pollutants by the Central Pollution Control Board (CPCB), India during 2005-2010 from 13 urban locations in India have been analyzed to get an insight into their temporal and spatial variability. Stations are chosen to represent the entire Indian region: Indo-Gangetic plain or 'IGP' (Jalandhar, Delhi, Kanpur, Durgapur, Kolkata, Guwahati), western India (Jodhpur, Ahmedabad, Surat), central India (Nagpur, Hyderabad) and southern India (Chennai, Trivandrum). The monthly averaged surface level SO2 and NO2 have also been compared with monthly columnar averages of these gases as detected by the Ozone monitoring Instrument (OMI) over these station grids. Mean SO2 concentrations are found to be the highest for Surat (7.5 ppbv), located in a highly industrialized region. Elevated levels of NO2, observed for Durgapur and Kolkata (31 ppbv each), are close to the 24-hour 'National Ambient Air Quality' standard (30 ppbv). The surface concentrations for both SO2 and NO2 concentrations are found to be the highest during winter. Columnar SO2 over many stations show a maximum during summer monsoon. For most IGP stations, columnar NO2 values are elevated during winter. Wavelet analyses revealed an annual periodicity in surface data for SO2 and NO2. Identifiable seasonality is found for NO2 (surface and column) over several stations using X-12-ARIMA monthly seasonal adjustment method. The ratios for different seasonal pairs vary between 0.6 to 2.0 for both SO2 and NO2 at the surface level. The winter to post-monsoon ratios are highest for columnar SO2 and minimum for columnar NO2. Significant correlations between SO2 and NO2 at surface are obtained for cities in industrial corridors viz. Surat and Durgapur, due to emissions from industries and power plants. For most of the stations analyzed, NO2 and CO (co-emitted with NO2 during combustion) columns show good correlation indicating anthropogenic influences. Statistically significant correlations between columnar-NO2 and surface-NO2 obtained for Delhi and Kolkata along with very low SO2 to NO2 ratios (<=0.2) indicate emissions from transport sector as major contributors to the ambient air over these regions. The findings are important and useful in the context of regional climate change occurring from anthropogenic emissions as well as from the perspective of emission inventories. These combined impacts of emissions, meteorology and transport on the air quality over this part of Asia would be explored in detail during the presentation.

Mallik, C.; Lal, S.

2012-12-01

5

Sorption of O 3, SO 2, NO 2 or their mixture by nine Poa pratensis cultivars of differing pollutant sensitivity  

NASA Astrophysics Data System (ADS)

Plants of nine Kentucky bluegrass ( Poa pratensis L.) cultivars were exposed to O 3, SO 2, NO 2 or a mixture of the three gases for three days to determine absorption and adsorption rates of each gas. Absorption rates into stomates differed among cultivars and generally decreased with longer exposure. Leaves of insensitive cultivars generally absorbed less of the single gases than those of sensitive cultivars. There was less absorption of each gas from the mixture than from the single gases. Adsorption rates on leaf surfaces were not always related to cultivar sensitivity and generally decreased less than did adsorption rates with longer exposure. Adsorption rates of O 3 were higher from the single than from mixed gas exposure and of SO 2 were similar from either single or mixed exposure, while the higher rate of NO 2 adsorption, whether from single or mixed gases, varied with cultivar.

Elkiey, T.; Ormrod, D. P.

6

Carbon catalyzed SO2 oxidation by NO2 and O3  

NASA Technical Reports Server (NTRS)

The oxidation of SO2 to sulfate on carbon particles by trace quantities of NO2 and O3 was studied. Particulate carbon black was either: (1) directly exposed on the pan of a microbalance to various humidified mixtures of SO2 and oxidant gas and the resultant weight gains monitored, or (2) the gas mixtures were bubbled through aqueous suspensions of carbon black and pure water blanks. In each set of experiments the run times were varied appropriately and the yields of sulfate were determined analytically. Conversion of SO2 to sulfate was thus characterized as a function of exposure time and of oxidant gas. Carbon black was determined to be an excellent catalyst for SO2 oxidation to sulfate by both NO2 and O3. No saturation effects were observed in either experimental approach. Conversions of SO2 to sulfate did not appear pH dependent.

Cofer, W. R., III; Schryer, D. R.; Rogowski, R. S.

1982-01-01

7

REMOVAL OF SO2 FROM INDUSTRIAL WASTE GASES  

EPA Science Inventory

The paper discusses technology for sulfur dioxide (SO2) pollution control by flue gas cleaning (called 'scrubbing') in the utility industry, a technology that has advanced significantly during the past 5 years. Federal Regulations are resulting in increasingly large-scale applica...

8

Concentrations of NO2, SO2, and benzene across Hanoi measured by passive diffusion samplers  

NASA Astrophysics Data System (ADS)

The concentrations of NO2, SO2, and benzene were measured by passive diffusion samplers at 96 sites across Hanoi consisting of 80 sites in the inner city background, 6 traffic hot spots, 5 industry hot spots, and 5 rural sites. Two sampling campaigns were conducted in the winter and summer seasons of 2007, and the average concentration of the two campaigns was used as a proxy for the annual mean. The annual means of NO2, SO2, and benzene in the inner city background ranged from 17.9 to 65.9 ?g m-3, 11.7-47.4 ?g m-3, and 3.5 to 15.4 ?g m-3, respectively. The NO2/benzene and SO2 concentrations were higher at the traffic and industry hot spots, respectively. The background concentrations of NO2 and benzene tended to increase with the population density and were highest in crowded Hanoi downtown areas. These areas are facing high risks of violating the national legislation threshold for NO2 (40 ?g-3). The SO2 background concentrations were generally below the legislation threshold (50 ?g-3). Motorbikes, which dominate the Hanoi vehicle fleet, are the main polluters of NO2 and benzene, whereas SO2 comes mainly from diesel buses and trucks, except in some areas that are directly affected by industrial coal burning. Stringently regulating the exhaust emissions of vehicles, especially for motorbikes, and reducing the sulfur and benzene contents in fuels could be implemented to improve Hanoi's air quality.

Hien, P. D.; Hangartner, M.; Fabian, S.; Tan, P. M.

2014-05-01

9

Carbon-catalyzed oxidation of SO2 by NO2 and air  

NASA Technical Reports Server (NTRS)

A series of experiments was performed using carbon particles (commercial furnace black) as a surrogate for soot particles. Carbon particles were suspended in water, and gas mixtures were bubbled into the suspensions to observe the effect of carbon particles on the oxidation of SO2 by air and NO2. Identical gas mixtures were bubbled into a blank containing only pure water. After exposure each solution was analyzed for pH and sulfate. It was found that NO2 greatly enhances the oxidation of SO2 to sulfate in the presence of carbon particles. The amount of sulfate found in the blanks was significantly less. Under the conditions of these experiments no saturation of the reaction was observed and SO2 was converted to sulfate even in a highly acid medium (pH or = 1.5).

Rogowski, R. S.; Schryer, D. R.; Cofer, W. R., III; Edahl, R. A., Jr.; Munavalli, S.

1982-01-01

10

Oxidation of SO2 by NO2 and air in an aqueous suspension of carbon  

NASA Technical Reports Server (NTRS)

A series of experiments has been performed using carbon black as a surrogate for soot particles. Carbon black was suspended in water and gas mixtures were bubbled into the suspensions to observe the effect of carbon particles on the oxidation of SO2 by air and NO2. Identical gas mixtures were bubbled into a black containing only pure water. After exposure each solution was analyzed for pH and sulfate. It was found that NO2 greatly enhances the oxidation of SO2 to sulfate in the presence of carbon black. The amount of sulfate in the blanks was significantly less. Under the conditions of the experiments no saturation of the reaction was observed and SO2 was converted to sulfate even in a highly acid medium (pH not less than 1.5).

Rogowski, R. S.; Schryer, D. R.; Cofer, W. R., III; Edahl, R. A., Jr.; Munavalli, S.

1982-01-01

11

Health risks of NO 2, SPM and SO 2 in Delhi (India)  

NASA Astrophysics Data System (ADS)

There is increasingly growing evidence linking urban air pollution to acute and chronic illnesses amongst all age groups. Therefore, monitoring of ambient concentrations of various air pollutants as well as quantification of the dose inhaled becomes quite important, specially in view of the fact that in many countries, policy decisions for reducing pollutant concentrations are mainly taken on the basis of their health impacts. The dose when gets combined with the likely responses, indicates the ultimate health risk (HR). Thus, as an extension of our earlier studies, HR has been estimated for three pollutants, namely, suspended particulate matter (SPM), nitrogen dioxide (NO 2) and sulfur dioxide (SO 2) for Delhi City in India. For estimation and analyses, three zones have been considered, namely, residential, industrial and commercial. The total population has been divided into three age classes (infants, children and adults) with different body weights and breathing rates. The exercise takes into account age-specific breathing rates, body weights for different age categories and occupancy factors for different zones. Results indicate that health risks due to air pollution in Delhi are highest for children. For all age categories, health risks due to SO 2 (HR_SO 2) are the lowest. Hence, HR_SO 2 has been taken as the reference with respect to which HR values due to SPM and NO 2 have been compared. Taking into account all the age categories and their occupancy in different zones, average HR values for NO 2 and SPM turn out to be respectively 22.11 and 16.13 times more than that for SO 2. The present study can be useful in generating public awareness as well as in averting and mitigating the health risks.

Pandey, Jai Shanker; Kumar, Rakesh; Devotta, Sukumar

12

SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES  

SciTech Connect

It is well known that natural and synthetic zeolites (molecular sieves) can adsorb gaseous SO2 from flue gas and do it more efficiently than lime based scrubbing materials. Unfortunately their cost ($500-$800 per ton) has deterred their use in this capacity. It is also known that zeolites are easy to synthesize from a variety of natural and man-made materials. The overall objective of the current work has been to evaluate the feasibility of having a utility synthesize its own zeolites, on-site, from fly ash and other recycled materials and then use these zeolites to adsorb SO2 from their flue gases. Work to date has shown that the efficiency of the capture process is related to the degree of crystallinity and the type of zeolite that forms in the samples. Normally, those samples cured at 150°C contained a greater proportion of zeolite and as such were more SO2 adsorptive than their low-temperature counterparts. However, in order for the project to be successful, on site synthesis must remain an option, i.e. _100°C synthesis. In light of this, the experimental focus now has two aspects. First, compositions of the starting materials are being altered by blending the current suite of fly ashes with other fly ashes, ground glass cullet and silica fume to promote the formation and growth of well crystallized and highly adsorptive zeolites. Second, greater degrees of reaction at significantly lower temperatures are being promote by ball milling the fly ash prior to use, by the use of more concentrated caustic solutions, and by the addition of zeolite seeds to the reactants. In all cases studies will focus on the effect of structure type and degree of conversion on SO2 adsorption. Future work will concentrate on the study of the effect of weathering on the suitability of converting fly ash into zeolites. This is an especially important study, considering the acres of fly ash now in storage throughout the country.

MICHAEL GRUTZECK

1998-10-31

13

SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES  

SciTech Connect

It is well known that natural and synthetic zeolites (molecular sieves) can adsorb gaseous SO{sub 2} from flue gas and do it more efficiently than lime based scrubbing materials. Unfortunately their cost ($500-$800 per ton) has deterred their use in this capacity. It is also known that zeolites are easy to synthesize from a variety of natural and man-made materials. The overall objective of the current work has been to evaluate the feasibility of having a utility synthesize its own zeolites, on-site, from fly ash and other recycled materials and then use these zeolites to adsorb SO{sub 2} from their flue gases. Work to date has shown that the efficiency of the capture process is related to the degree of crystallinity and the type of zeolite that forms in the samples. Normally, those samples cured at 150 C contained a greater proportion of zeolite and as such were more SO{sub 2} adsorptive than their low-temperature counterparts. However, in order for the project to be successful, on site synthesis must remain an option, i.e. 100 C synthesis. In light of this, the experimental focus now has two aspects. First, compositions of the starting materials are being altered by blending the current suite of fly ashes with ground glass cullet and silica fume to promote the formation and growth of well crystallized and highly adsorptive zeolites. Second, greater degrees of reaction at significantly lower temperatures are being promote by ball milling the fly ash prior to use, by the use of more concentrated caustic solutions, and by the addition of zeolite seeds to the reactants. In all cases studies will focus on the effect of structure type and degree of conversion on SO{sub 2} adsorption. Future work will concentrate on the study of the effect of weathering on the suitability of converting fly ash into zeolites. This is an especially important study, considering the acres of fly ash now in storage throughout the US.

Michael Grutzeck

1999-04-30

14

Long path monitoring of tropospheric O3, NO2, H2CO and SO2  

NASA Technical Reports Server (NTRS)

Concentrations of tropospheric O3, NO2, H2CO, and SO2 have been measured on the Campus of the 'Universite Libre de Bruxelles' on a routine basis since October 1990. The long path system consists of a source lamp, a first 30 cm f/8 Cassegrain type telescope which collimates the light onto a slightly parabolic mirror placed on the roof of a building situated 394 m away from the laboratory. The light is sent back into a second 30 cm Cassegrain telescope. This telescope has been modified so that the output beam is a 5 cm diameter parallel beam. This beam is then focused onto the entrance aperture of the BRUKER IFS120HR fourier transform spectrometer. The two telescopes are mounted on alignment devices and the external mirror is equipped with a driving system operated from the laboratory. The choice of the light source (either a 1000 W high pressure 'ozone free' xenon lamp or a 250 W tungsten filament) and of the detector (either a solar blind UV-diode or a silicon diode) depended on the spectral region studied. These regions lie respectively from 26,000 cm(exp -1) to 30,000 cm(exp -1) (260-380 nm) and from 14,000 cm(exp -1) to 30,000 cm(exp -1) (330-700 nm). The spectra have been recorded at the resolution of 16 cm(exp -1) and with a dispersion of 7.7 cm(exp -1). They have been measured during the forward and the backward movements of the mobile mirror, in double sided mode; each spectrum is an average of 2000 scans. The time required to record a spectrum is about 45 minutes. The shape of the raw spectra in the two investigated regions are represented.

Vandaele, A. C.; Carleer, M.; Colin, R.; Simon, P. C.

1994-01-01

15

The Distribution and Origin of Radon, CO2 and SO2 Gases at Arenal Volcano, Costa Rica  

E-print Network

The Distribution and Origin of Radon, CO2 and SO2 Gases at Arenal Volcano, Costa Rica par Glyn mémoire intitulé The Distribution and Origin of Radon, CO2 and SO2 Gases at Arenal Volcano, Costa Rica in northwestern Costa Rica, Arenal is one of the most active volcanoes in Central America, having been

Williams-Jones, Glyn

16

SUMMARY OF AUDIT PERFORMANCE: MEASUREMENT OF SO2, NO2, SULFATE, NITRATE, LEAD, HI-VOL FLOW RATE, 1978  

EPA Science Inventory

The report summarizes the results of the quality assurance audits for the period from January, 1978 through December, 1978. Pollutants for which audits were conducted and results reported are SO2, NO2, sulfate, nitrate, lead, and hi-vol flow rate. The operation of the EPA audit p...

17

SUMMARY OF AUDIT PERFORMANCE: MEASUREMENT OF SO2, NO2, CO, SULFATE, NITRATE, LEAD, HI-VOL FLOW RATE  

EPA Science Inventory

The report summarizes the results of the quality assurance audits for the period from October 1976 through December 1977. Pollutants for which audits were conducted and results reported are SO2, NO2, sulfate, nitrate, lead, and hi vol flow rate. The operation of the EPA audit pro...

18

Reactive uptake and hydration experiments on amorphous carbon treated with NO2, SO2, O3, HNO3, and H2SO4  

NASA Astrophysics Data System (ADS)

The reactivity and hydration properties of amorphous carbon were studied in a low-pressure Knudsen cell reactor at room temperature (298 K). Reactions of NO2 (?=0.11±0.04) and HNO3 (?=0.038±0.008) were observed and may be important for nitrogen partitioning in the atmosphere. Water uptake was measured before and after exposure to various gases. Treating the amorphous carbon with NO2 and O3 does not alter the H2O uptake, while treatment with SO2, HNO3, and H2SO4 significantly increases the H2O uptake. The experimental results support current assumptions in jet aircraft plume models that sulfuric acid condensation is involved in the activation of soot particles as condensation nuclei.

Rogaski, C. A.; Golden, D. M.; Williams, L. R.

19

Homogeneous and heterogeneous radiation induced NO and SO 2 removal from power plants flue gases—modeling study  

Microsoft Academic Search

The generalized mathematical model has been developed for radiation induced removal of NO and SO2 from flue gases of power plants. This model includes energy absorption of electron beam with active species generation, reactions in gas phase, aerosol formation and growth, and liquid-phase chemistry. To investigate the role of various process parameters (initial NO and SO2 concentrations, temperature, humidity, absorbed

G. Y. Gerasimov; T. S. Gerasimova; V. N. Makarov; S. A. Fadeev

1996-01-01

20

O3, SO2, NO2, and UVB measurements in Beijing and Baseline Station of northwestern part of China  

NASA Technical Reports Server (NTRS)

A MKII Brewer ozone spectrometer was used in Beijing from Oct. 1990 to June 1991 to measure O3, SO2 and UVB radiation. And since Nov. 1991 a new MKIV Brewer spectrometer, which can take the measurements of O3, SO2, NO2 and UVB radiation, has been set up in Beijing. The MKII Brewer spectrometer was moved to Qinghai baseline station which is on the Qinghai-tibetean plateau in the northwestern part of China. Both the data in Beijing and Qinghai baseline station has been analyzed and some results will be shown here along with the ozone profiles botained through the Umkehr program given by AES of Canada for the Brewer ozone spectrometer.

Guo, Song; Zhou, Xiuji; Zhang, Xiachun

1994-01-01

21

Evaluating emissions of HCHO, HONO, NO2, and SO2 from point sources using portable Imaging DOAS  

NASA Astrophysics Data System (ADS)

Our ability to quantitatively describe urban air pollution to a large extent depends on an accurate understanding of anthropogenic emissions. In areas with a high density of individual point sources of pollution, such as petrochemical facilities with multiple flares or regions with active commercial ship traffic, this is particularly challenging as access to facilities and ships is often restricted. Direct formaldehyde emissions from flares may play an important role for ozone chemistry, acting as an initial radical precursor and enhancing the degradation of co-emitted hydrocarbons. HONO is also recognized as an important OH source throughout the day. However, very little is known about direct HCHO and HONO emissions. Imaging Differential Optical Absorption Spectroscopy (I-DOAS), a relatively new remote sensing technique, provides an opportunity to investigate emissions from these sources from a distance, making this technique attractive for fence-line monitoring. In this presentation, we will describe I-DOAS measurements during the FLAIR campaign in the spring/summer of 2009. We performed measurements outside of various industrial facilities in the larger Houston area as well as in the Houston Ship Channel to visualize and quantify the emissions of HCHO, NO2, HONO, and SO2 from flares of petrochemical facilities and ship smoke stacks. We will present the column density images of pollutant plumes as well as fluxes from individual flares calculated from I-DOAS observations. Fluxes from individual flares and smoke stacks determined from the I-DOAS measurements vary widely in time and by the emission sources. We will also present HONO/NOx ratios in ship smoke stacks derived from the combination of I-DOAS and in-situ measurements, and discuss other trace gas ratios in plumes derived from the I-DOAS observations. Finally, we will show images of HCHO, NO2 and SO2 plumes from control burn forest fires observed in November of 2009 at Vandenberg Air Force Base, Santa Maria, CA.

Pikelnaya, O.; Tsai, C.; Herndon, S. C.; Wood, E. C.; Fu, D.; Lefer, B. L.; Flynn, J. H.; Stutz, J.

2011-12-01

22

Groundbreaking constraints on emissions from GEO-CAPE: case studies of CH4, NH3, SO2 and NO2  

NASA Astrophysics Data System (ADS)

While existing remote sensing measurements currently provide valuable sources of top-down constraints on a wide range of emissions of air pollutants and greenhouse gases, geostationary observations hold the potential to significantly advance our scientific understanding of constituent sources in several ways. Over North America, the proposed GEO-CAPE instrument will allow replacement of monthly mean and annual average estimates of emissions, ones that are tuned to current and/or historical observations, with detailed mechanistic models that are capable of projecting outside the envelope of current observations. GEO-CAPE observations are expected to be a major leap forward in observations that can test and constrain such models. In this manner, GEO-CAPE will also allow development of high space and time resolution emission fields that will enable detailed evaluation of other components of a chemical transport model (e.g. boundary layer fluid dynamics). Here we present case studies of the expected benefits of GEO-CAPE observations for constraining bi-directional fluxes of ammonia, the sources and chemical evolution of NOx, the lifetime of SO2, and the emissions of CH4 from anthropogenic vs natural sources. In each case, we illustrate the ways in which geostationary observations provide insight beyond current capabilities with low earth orbit satellites.

Jeong, G.; Bash, J. O.; Cady-Pereira, K. E.; Henze, D. K.; Cohen, R. C.; Krotkov, N. A.; Lamsal, L.; Li, C.; Wecht, K.; Worden, J.; Worden, H. M.; Perkins, A.

2012-12-01

23

Identification of gaseous SO2 and new upper limits for other gases on Io  

Microsoft Academic Search

The identification of gaseous sulfur dioxide on Io by Voyager 1 is reported, and preliminary upper limits for other atmospheric gases are presented. Averaged spectra taken by the Voyager IRIS experiment in the range of 1,000 to 1,200\\/cm are interpreted as containing three fundamental sulfur dioxide bands, with intensities most nearly corresponding to an atmospheric model with a sulfur dioxide

J. Pearl; R. Hanel; V. Kunde; W. Maguire; K. Fox; S. Gupta; C. Ponnamperuma; F. Raulin

1979-01-01

24

Nocturnal Vertical Gradients of O3, NO2, NO3, HONO, HCHO, and SO2 in Los Angeles, CA, during CalNex 2010  

NASA Astrophysics Data System (ADS)

Nocturnal chemistry, through the conversion and removal of air pollutants, plays an important role in determining the initial condition for photochemistry during the following day. In the stable nocturnal boundary layer (NBL) the interplay between suppressed vertical mixing and surface emissions of NOx and VOCs can result in pronounced vertical trace gas profiles. The resulting altitude dependence of nocturnal chemistry makes the interpretation of ground observations challenging. In particular, the quantification of the nocturnal loss of NOx, due to NO3 and N2O5 chemistry, requires observations throughout the entire vertical extent of the NBL. The formation of daytime radical precursors, such as HONO, is also altitude dependent. An accurate assessment of their impact on daytime chemistry requires measurements of their profiles during the night and morning. Here we present observations from the CalNex-LA experiment, which took place from May 15 to June 15, 2010 on the east side of the Los Angeles Basin, CA. A Long-Path Differential Optical Absorption Spectrometer (LP-DOAS) was set up on the roof of the Millikan library (265 m asl, 35m agl) on the campus of the California Institute of Technology. Four retroreflector arrays were mounted about 5 -7 km North-East of the instrument at 310m, 353m, 487m and 788 m asl. The vertical profiles of NO3, HONO, NO2, O3, HCHO, and SO2 were retrieved at altitude intervals of 35-78m, 78-121m, 121-255m and 255-556m above the ground. During many nights vertical gradients were observed, with elevated NO2 and HONO concentrations near the surface and larger ozone and NO3 concentrations aloft. Simultaneous ceilometer observations of the NBL structure show the impact of meteorology on the vertical trace gas distributions. We will discuss the consequences of trace gases gradients on the nocturnal NOx budget.

Tsai, J.; Pikelnaya, O.; Hurlock, S. C.; Wong, K.; Cheung, R.; Haman, C. L.; Lefer, B. L.; Stutz, J.

2010-12-01

25

Geographical & Environmental Modelling, Vol. 4, No. 2, 2000, 131161 Critical Levels of SO2 in Northern Czech  

E-print Network

BARKMAN & PER ARVIDSSON ABSTRACT Three methods estimating adverse effects of SO2 on Norway spruce forests University, S-221 00 Lund, Sweden. E-mail: jonas.ardo@natgeo.lu.se. Andreas Barkman, Department of Chemical

Ardö, Jonas

26

Quantification of NO2 and SO2 emissions from the Houston Ship Channel and Texas City industrial areas during the 2006 Texas Air Quality Study  

NASA Astrophysics Data System (ADS)

In August-September 2006, as part of the Second Texas Air Quality Study, NO2 and SO2 emissions from the Houston Ship Channel and Texas City industrial areas were quantified using mobile mini-differential optical absorption spectroscopy instruments. The measured NO2 emissions from the Houston Ship Channel and Texas City industrial areas were 2542 and 452 kg h-1, respectively, yielding NOx emissions 70% and 43%, respectively, above the reported inventory values. Quantified SO2 emissions from the Houston Ship Channel area were 1749 kg h-1 and were found to be 34% above the values reported in the inventory. Short-term variability of NO2 and SO2 emissions was found at the Houston Ship Channel. On 31 August 2006, a plume was detected at the HSC during three consecutive measurements, yielding a HCHO flux of 481 kg h-1. This event has been mainly attributed to photochemical production.

Rivera, Claudia; Mellqvist, Johan; Samuelsson, Jerker; Lefer, Barry; Alvarez, Sergio; Patel, Monica R.

2010-04-01

27

Simultaneous treatment of SO2 containing stack gases and waste water  

NASA Technical Reports Server (NTRS)

A process for simultaneously removing sulfur dioxide from stack gases and the like and purifying waste water such as derived from domestic sewage is described. A portion of the gas stream and a portion of the waste water, the latter containing dissolved iron and having an acidic pH, are contacted in a closed loop gas-liquid scrubbing zone to effect absorption of the sulfur dioxide into the waste water. A second portion of the gas stream and a second portion of the waste water are controlled in an open loop gas-liquid scrubbing zone. The second portion of the waste water contains a lesser amount of iron than the first portion of the waste water. Contacting in the openloop scrubbing zone is sufficient to acidify the waste water which is then treated to remove solids originally present.

Poradek, J. C.; Collins, D. D. (inventors)

1978-01-01

28

Effect of the greenhouse gases (CO2, H2O, SO2) on Martian paleoclimate  

NASA Technical Reports Server (NTRS)

There is general agreement that certain surface features on Mars are indicative of the presence of liquid water at various times in the geologic past. In particular, the valley networks are difficult to explain by a mechanism other than the flow of liquid water. It has been suggested in several studies that a thick CO2 atmosphere on Mars early in its history could have provided a greenhouse warming that would have allowed the flow of water either on the surface or just below the surface. However, this effect was examined with a detailed radiation model, and it was found that if reduced solar luminosity early in the history of the solar system is taken into account, even three bars of CO2 will not provide sufficient greeenhouse warming. The addition of water vapor and sulflur dioxide (both plausible gases that may have been emitted by Martian volcanoes) to the atmosphere also fail to warm the surface above 273 K for reduced solar luminosity conditions. The increase in temperature may be large enough, however, for the formation of these features by brines.

Postawko, S. E.; Kuhn, W. R.

1986-01-01

29

In-situ characterisation of aerosol and gases (SO2, HCl, ozone) in Mt Etna volcano plume  

NASA Astrophysics Data System (ADS)

We present findings from a measurement campaign that deployed a range of in-situ real-time atmospheric measurement techniques to characterise aerosols and gases in Mt Etna plume in October 2013. The LOAC (Light Optical Aerosol Counter) instrument for size-resolved particle measurements was deployed alongside two Multi-Gas instruments (measuring SO2, H2S, HCl, CO2) and an ozone sensor. Measurements were performed at the summit craters (in cloudy- and non-cloudy conditions) and in grounding downwind plume on the volcano flank. These high frequency measurements (acid gases: 1 to 0.1 Hz, aerosol: 0.1 Hz) provide a detailed in-situ dataset for time-resolved plume characterisation and volcano monitoring. The LOAC measurement of sized-resolved aerosol (over a 0.2 to 50 µm particle diameter range) alongside SO2 (10's ppbv to 10's ppmv) provides a valuable dataset for determining the volcanic aerosol volume and surface area to SO2 ratios. These parameters are presently poorly defined but are important for atmospheric models of the reactive halogen chemistry that occurs on volcanic aerosol surfaces to convert volcanic HBr into reactive bromine, including BrO. The LOAC's patented optical design can also provide insights into particle properties. The two Multi-Gas SO2 time-series show good agreement, detecting co-varying plume fluctuations in the downwind plume, which also correlate with the LOAC total aerosol volume time-series. An estimate of HCl/SO2 in Etna emissions was made by Multi-Gas electrochemical sensor, using a novel design to limit absorption/desorption effects and low-noise electronics for improved resolution. The detection of volcanic HCl by electrochemical sensor brings new possibilities for Multi-Gas monitoring of volcanic halogen emissions. Electrochemical sensor response times are not instantaneous, particularly for sticky gases such as HCl (T90 ~min), but also even for "fast" response (T90 ~ 10 to 30 s) sensors such as SO2 and H2S. However, in a volcanic plume environment, Multi-Gas instruments are exposed to very rapidly fluctuating gas concentrations due to turbulent plume eddies. The combination of these effects can introduce measurement errors, emphasizing a need for sensor response modelling approaches for accurate determination of gas ratios from Multi-Gas instruments. Measurement of ozone in volcanic plume is of interest to quantify the atmospheric impact of rapid reactive halogen chemistry cycles that occur in the dispersing plume, depleting ozone. The UV-based ozone sensor we deployed exhibited a positive cross-sensitivity to SO2 (as expected) that dominated the signal in strong plume. In the dilute (few ppmv SO2) grounding plume, near-ambient ozone concentrations were observed. However the instrument was also occasionally subject to an interference (under evaluation, but potentially from mercury). Nevertheless, the data provide some constraints on BrO-mediated ozone loss in near-source volcanic plumes, towards improved initialisation of atmospheric chemistry models that aim to simulate this process.

Roberts, Tjarda; Vignelles, Damien; Giudice, Gaetano; Liuzzo, Marco; Aiuppa, Alessandro; Chartier, Michel; Coute, Benoit; Lurton, Thibaut; Renard, Jean-Baptiste

2014-05-01

30

E-Beam SO2 and NOx removal from flue gases in the presence of fine water droplets  

NASA Astrophysics Data System (ADS)

The Electron Beam Flue Gas Treatment (EBFGT) has been proposed as an efficient method for removal of SO2 and NOx many years ago. However, the industrial application of this procedure is limited to just a few installations. This article analyses the possibility of using medium-power EB accelerators for off-gases purification. By increasing electron energy from 0.7 MeV to 1-2 MeV it is possible to reduce the energy losses in the windows and in the air gap between them (transformer accelerators can be applied as well in the process). In order to use these mid-energy accelerators it is necessary to reduce their penetration depth through gas and this can be achieved by increasing the density of the reaction medium by means of dispersing a sufficient amount of fine water droplets (FWD). The presence of FWD has a favorable effect on the overall process by increasing the level of liquid phase reactions. A special reactor was designed and built to test the effect of FWD on the treatment of flue gases with a high concentration of SO2 and NOx using high-energy EBs (9 MeV). By determining the energy efficiency of the process the favorable effect of using FWD and high-energy EB was demonstrated.

Calinescu, Ioan; Martin, Diana; Chmielewski, Andrezj; Ighigeanu, Daniel

2013-04-01

31

A four-channel portable solar radiometer for measuring particulate and/or aerosol opacity and concentration of NO2 and SO2 in stack plumes  

NASA Technical Reports Server (NTRS)

Solar absorption radiometry has been investigated as a method of measuring stackplume effluents. A simple and inexpensive instrument was constructed for observing the sun at four wavelengths: 800, 600, 400, and 310 nm. Higher wavelength channels measured the effect of the particulates and NO2, and an ultraviolet channel measured the contribution of SO2 to the attenuation. Stack-plume measurements of opacity and concentration of NO2 and SO2 were in basic agreement with in-stack measurements. The major limitation on the use of the radiometer is the requirement for an accessible viewing position which allows the sun-plume-observer relationship to be attained. It was concluded that the solar radiometer offers an inexpensive method for monitoring plume effluents when the viewing position is not restricted.

Exton, R. J.; Gregory, R. W.

1976-01-01

32

Scanning and mobile multi-axis DOAS measurements of SO2 and NO2 emissions from an electric power plant in Montevideo, Uruguay  

NASA Astrophysics Data System (ADS)

In March 2012 the emissions of NO2 and SO2 from a power station located on the east side of Montevideo Bay (34° 53? 10? S, 56° 11? 49? W) were quantified by simultaneously using mobile and scanning multi-axis differential optical absorption spectroscopy (in the following mobile DOAS and scanning DOAS, respectively). The facility produces electricity by means of two technologies: internal combustion motors and steam generators. The motors are powered with centrifuged heavy oil and produce a maximum power of 80 MW approximately. The steam generators produce approximately 305 MW and are powered with heavy fuel oil. We compare the emissions obtained from the measured slant column densities (mobile DOAS and scanning DOAS) with the emissions estimated from fuel mass balance. On one occasion it was possible to distinguish between the two types of sources, observing two plumes with different SO2 and NO2 emission rates. During the period of the campaign the mean SO2 emission flux was determined to be 0.36 (±0.12) kg s-1 and 0.26 (±0.09) kg s-1 retrieved from mobile and scanning DOAS respectively, while the calculated SO2 flux from the sulphur content of the fuel was 0.34 (±0.03) kg s-1. The average NO2 flux calculated from mobile DOAS was determined to be 11 (±3) × 10-3 kg s-1. Using the scanning DOAS approach a mean NO2 flux of 5.4 (±1.7) × 10-3 kg s-1 was obtained, which is significantly lower than by the mobile measurements. The differences between the results of mobile MAX-DOAS measurements and scanning DOAS measurements are most probably caused by the variability and the limited knowledge of the wind speed and direction.

Frins, E.; Bobrowski, N.; Osorio, M.; Casaballe, N.; Belsterli, G.; Wagner, T.; Platt, U.

2014-12-01

33

Ship-based MAX-DOAS measurements of tropospheric NO2 and SO2 in the South China and Sulu Sea  

NASA Astrophysics Data System (ADS)

In November 2011, ship-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were performed within the SHIVA campaign on board RV Sonne in the South China and Sulu Sea. Spectral measurements for a total of eleven days could be used to retrieve tropospheric slant column densities (SCDs) of nitrogen dioxide (NO2) and sulfur dioxide (SO2) in the marine environment. The NO2 fit was performed following recommendations developed during the CINDI campaign and adapted for the ship-based measurements. We found that the inclusion of a cross section for liquid water and an empirical correction spectrum accounting for the effects of liquid water and vibrational Raman scattering (VRS) slightly improved the NO2 fit quality, especially at lower elevation angles and for lower NO2 levels. The conversion of SCDs into tropospheric NO2 vertical columns (TVC NO2) has been achieved using both a simple geometric approach and the Bremian advanced MAX-DOAS Retrieval Algorithm (BREAM), which is based on the optimal estimation method and accounts for atmospheric radiative transfer. We found good agreement between the geometric approach using the 15° measurements and BREAM, revealing that measurements at 15° elevation angle can be used for retrieving TVC NO2 in tropical marine environments when SZA is smaller than 75°. As expected, the values of TVC NO2 were generally low (<0.5 × 1015 molec cm-2) when no sources of NOx were in proximity to the RV Sonne. However, we found increased values of TVC NO2 (>2 × 1015 molec cm-2) in the morning when the RV Sonne was heading along the coast of Borneo. This is in good agreement with satellite measurements. The results of the profile retrieval show that the boundary layer values of NO2 are <30 pptv in the open and clean tropical marine environment. Interestingly, we also found elevated tropospheric SO2 amounts for measurements taken in a busy shipping lane, consistent with the time series of tropospheric NO2.

Schreier, S. F.; Peters, E.; Richter, A.; Lampel, J.; Wittrock, F.; Burrows, J. P.

2015-02-01

34

Transverse approach between real world concentrations of SO2, NO2, BTEX, aldehyde emissions and corrosion in the Grand Mare tunnel.  

PubMed

With regard to automotive traffic, a tunnel-type semi enclosed atmosphere is characterized by a higher concentration of gaseous pollutants than on urban traffic roads and highlights the gaseous effluent species having an impact on material degradation. Therefore, a transverse approach between air quality and its consequences upon the longevity of materials is necessary, implying better knowledge of tunnel atmosphere and a better understanding of material degradation inside a tunnel for operating administration. Gaseous pollutant measurements carried out in a road tunnel in Rouen (Normandy) give the real world traffic concentrations of experimental exposure conditions. The sampling campaigns, achieved in summer and winter include SO2, NO2, BTEX and aldehyde analyses. Effluent profiles in the upward and downward tubes have been established. The current work shows that SO2, NO2, formaldehyde, acetaldehyde, propanal and butanal must be considered in the degradation process of materials in a stuffy environment. As regards NO2, its concentration depends on the modification of the automotive fleet. The total aldehyde concentrations indicate no particular trend between the two bores. Formaldehyde, acetaldehyde, propanal, butanal and acrolein species are the most abundant species emitted by vehicles and represent 90% to 95% of the total aldehyde emissions. PMID:23513445

Ameur-Bouddabbous, I; Kasperek, J; Barbier, A; Harel, F; Hannoyer, B

2012-01-01

35

A Longitudinal Study of Sick Building Syndrome (SBS) among Pupils in Relation to SO2, NO2, O3 and PM10 in Schools in China  

PubMed Central

There are fewer longitudinal studies from China on symptoms as described for the sick building syndrome (SBS). Here, we performed a two-year prospective study and investigated associations between environmental parameters such as room temperature, relative air humidity (RH), carbon dioxide (CO2), nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), particulate matter (PM10), and health outcomes including prevalence, incidence and remission of SBS symptoms in junior high schools in Taiyuan, China. Totally 2134 pupils participated at baseline, and 1325 stayed in the same classrooms during the study period (2010–2012). The prevalence of mucosal symptoms, general symptoms and symptoms improved when away from school (school-related symptoms) was 22.7%, 20.4% and 39.2%, respectively, at baseline, and the prevalence increased during follow-up (P<0.001). At baseline, both indoor and outdoor SO2 were found positively associated with prevalence of school-related symptoms. Indoor O3 was shown to be positively associated with prevalence of skin symptoms. At follow-up, indoor PM10 was found to be positively associated with new onset of skin, mucosal and general symptoms. CO2 and RH were positively associated with new onset of mucosal, general and school-related symptoms. Outdoor SO2 was positively associated with new onset of skin symptoms, while outdoor NO2 was positively associated with new onset of skin, general and mucosal symptoms. Outdoor PM10 was found to be positively associated with new onset of skin, general and mucosal symptoms as well as school-related symptoms. In conclusion, symptoms as described for SBS were commonly found in school children in Taiyuan City, China, and increased during the two-year follow-up period. Environmental pollution, including PM10, SO2 and NO2, could increase the prevalence and incidence of SBS and decrease the remission rate. Moreover, parental asthma and allergy (heredity) and pollen or pet allergy (atopy) can be risk factors for SBS. PMID:25398002

Zhang, Xin; Li, Fan; Zhang, Li; Zhao, Zhuohui; Norback, Dan

2014-01-01

36

Hydrothermal buffering of the SO2\\/H2S ratio in volcanic gases: Evidence from La Fossa Crater fumarolic field, Vulcano Island  

Microsoft Academic Search

Sulfur speciation in volcanic gases is a potentially valuable tracer of degassing processes at volcanoes. Hitherto, observations of sulfur speciation in volcanic gas plumes have however been limited both in number and quality. Here, we report on periodic measurements of SO2 to H2S proportions in the volcanic gases from La Fossa volcano (Vulcano Island) performed during 2004–2006, a period which

A. Aiuppa; C. Federico; G. Giudice; S. Gurrieri; M. Valenza

2006-01-01

37

Emission measurements of alkenes, alkanes, SO2, and NO2 from stationary sources in Southeast Texas over a 5 year period using SOF and mobile DOAS  

NASA Astrophysics Data System (ADS)

A mobile platform for flux measurements of VOCs (alkanes and alkenes), SO2, and NO2 emissions using the Solar Occultation Flux (SOF) method and mobile differential optical absorption spectroscopy (DOAS) was used in four different studies to measure industrial emissions. The studies were carried out in several large conglomerates of oil refineries and petrochemical industries in Southeast and East Texas in 2006, 2009, 2011, and 2012. The measured alkane emissions from the Houston Ship Channel (HSC) have been fairly stable between 2006 and 2011, averaging about 11,500 kg/h, while the alkene emissions have shown greater variations. The ethene and propene emissions measured from the HSC were 1511 kg/h and 878 kg/h, respectively, in 2006, while dropping to roughly 600 kg/h for both species in 2009 and 2011. The results were compared to annual inventory emissions, showing that measured VOC emissions were typically 5-15 times higher, while for SO2 and NO2 the ratio was typically 0.5-2. AP-42 emission factors were used to estimate meteorological effects on alkane emissions from tanks, showing that these emissions may have been up to 35-45% higher during the studies than the annual average. A more focused study of alkene emissions from a petrochemical complex in Longview in 2012 identified two upset episodes, and the elevation of the total emissions during the measurement period due to the upsets was estimated to be approximately 20%. Both meteorological and upset effects were small compared to the factor of 5-15, suggesting that VOC emissions are systematically and substantially underestimated in current emission inventories.

Johansson, John K. E.; Mellqvist, Johan; Samuelsson, Jerker; Offerle, Brian; Lefer, Barry; Rappenglück, Bernhard; Flynn, James; Yarwood, Greg

2014-02-01

38

Inter-conversion of Chromium Species During Air Sampling: Effects of O3, NO2, SO2, Particle Matrices, Temperature and Humidity  

PubMed Central

The inter-conversion between Cr(VI), a pulmonary carcinogen, and Cr(III), an essential human nutrient, poses challenges to the measurement of Cr(VI) in airborne particles. Chamber and field tests were conducted to identify the factors affecting Cr(VI)-Cr(III) inter-conversion in the basic filter medium under typical sampling conditions. In the chamber tests, isotopically enriched 53Cr(VI) and 50Cr(III) were spiked on diesel particulate matter (DPM) and secondary organic aerosol (SOA) that were pre-collected on a basic MCE filter. The filter samples were then exposed to clean air or the air containing SO2 (50 and 160 ppb), 100 ppb O3, or 150 ppb NO2 for 24 hours at 16.7 LPM flow rate at designated temperature (20 and 31°C) and RH (40% and 70%) conditions. Exposure to 160 ppb SO2 had the greatest effect on 53Cr(VI) reduction, with 53Cr(VI) recovery of 31.7 ± 15.8% (DPM) and 42.0 ± 7.9% (SOA). DPM and SOA matrix induced 53Cr(VI) reduction when exposed to clean air while reactive oxygen species in SOA could promote 50Cr(III) oxidation. Deliquescence when RH increased from 40% to 70% led to conversion of Cr(III) in SOA, whereas oxidized organics in DPM and SOA enhanced hygroscopicity and thus facilitated Cr(VI) reduction. Field tests showed seasonal variation of Cr(VI)-Cr(III) inter-conversion during sampling. Correction of the inter-conversion using USEPA method 6800 is recommended to improve accuracy of ambient Cr(VI) measurements. PMID:23550818

Huang, Lihui; Fan, Zhihua (Tina); Yu, Chang Ho; Hopke, Philip K.; Lioy, Paul J.; Buckley, Brian T.; Lin, Lin; Ma, Yingjun

2013-01-01

39

Improved NO2 and SO2 satellite data products for pollution monitoring: evaluation over the Canadian oil sands and population centers  

NASA Astrophysics Data System (ADS)

The utility of space-based air quality sensors, such as the Ozone Monitoring Instrument (OMI), to help inform on surface levels of pollutants remains a challenge due to their coarse spatial resolution and lack of sensitivity to vertical distributions. In the case of nitrogen dioxide (NO2) and sulfur dioxide (SO2) progress in addressing these limitations has been made through development of a new Environment Canada (EC) air mass factor product that incorporates higher spatial and temporal resolution input information. This includes profile shapes from the EC operational air quality forecast model, GEM-MACH (Global Environmental Multiscale model - Modelling Air quality and CHemistry), running at 15 km resolution or better. These new EC air mass factors, when applied to OMI observations, were found to better capture spatial and temporal variability, including gradients near sources. In comparisons with surface stations, GEM-MACH was also used to help correct for the sampling and coarse OMI spatial resolution. Examples from the Canadian oil sands and urban centers (such as Toronto) will be used to illustrate this product.

McLinden, C. A.; Adams, C.; Fioletov, V.

2013-12-01

40

40 CFR Figure C-1 to Subpart C of... - Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO...Figure C-1 to Subpart C of Part 53—Suggested Format for Reporting Test Results for Methods for SO 2 , CO, O 3...

2010-07-01

41

Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents  

SciTech Connect

The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-particle dispersion and in the filter cake/filter medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic filter disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash from wood bark combustion, and NaHCO{sub 3} as well as Ca(OH){sub 2} as sorbent material (particle size d{sub 50}/d{sub 84} : 35/192 {micro}m, and 3.5/16, respectively). The pilot unit consists of an entrained flow reactor (gas duct) representing the raw gas volume of a filter house and the filter disk with a filter cake, operating continuously, simulating filter cake build-up and cleaning of the filter medium by jet pulse. Temperatures varied from 200 to 600 C, sorbent stoichiometric ratios from zero to 2, inlet concentrations were on the order of 500 to 700 mg/m{sup 3}, water vapor contents ranged from zero to 20 vol%. The experimental program with NaHCO{sub 3} is listed in Table 1. In addition, model calculations were carried out based on own and published experimental results that estimate residence time and temperature effects on removal efficiencies.

Hemmer, G.; Kasper, G.; Wang, J.; Schaub, G.

2002-09-20

42

Variation of H2O/CO2 and CO2/SO2 ratios of volcanic gases discharged by continuous degassing of Mount Etna volcano, Italy  

NASA Astrophysics Data System (ADS)

We applied the Multi-GAS technique to measure compositions of the volcanic plumes continuously discharged from summit craters of Voragine, Northeast and Bocca Nuova at Mount Etna, in an attempt to estimate compositions of the source volcanic gases. The estimated CO2/SO2 and H2O/CO2 ratios of the volcanic gases show a large variation ranging from 0.6 to 30 and from 1 to 18, respectively. This variability overlaps with the compositional range of dissolved volatiles in melt inclusions and their coexisting bubbles in a magma chamber and can be caused by the low-pressure degassing of a magma with variable bubble content ranging from 0.3 to 15 wt.%. The variable bubble content in the magma is likely a result of supply of deep-derived CO2-rich gas phase to the chamber and subsequent bubble-magma differentiation by bubble ascent in the magma chamber. In contrast, the variation of volcanic gas composition can also be caused by changes of degassing pressure (gas-magma separation pressure), ranging from 0 to 100 MPa, as a result of changes in the depth of the top of the convecting magma in volcanic conduits. Both mechanisms can cause similar compositional variations. However, the two mechanisms will result in contrasting correlations between the SO2 emission rates and the gas compositions that can be examined by parallel observations of the emission rates and compositions in the future.

Shinohara, H.; Aiuppa, A.; Giudice, G.; Gurrieri, S.; Liuzzo, M.

2008-09-01

43

Reactive and nonreactive quenching of O(1D) by the potent greenhouse gases SO2F2, NF3, and SF5CF3  

PubMed Central

A laser flash photolysis–resonance fluorescence technique has been employed to measure rate coefficients and physical vs. reactive quenching branching ratios for O(1D) deactivation by three potent greenhouse gases, SO2F2(k1), NF3(k2), and SF5CF3(k3). In excellent agreement with one published study, we find that k1(T) = 9.0 × 10-11 exp(+98/T) cm3 molecule-1 s-1 and that the reactive quenching rate coefficient is k1b = (5.8 ± 2.3) × 10-11 cm3 molecule-1 s-1 independent of temperature. We find that k2(T) = 2.0 × 10-11 exp(+52/T) cm3 molecule-1 s-1 with reaction proceeding almost entirely (?99%) by reactive quenching. Reactive quenching of O(1D) by NF3 is more than a factor of two faster than reported in one published study, a result that will significantly lower the model-derived atmospheric lifetime and global warming potential of NF3. Deactivation of O(1D) by SF5CF3 is slow enough (k3 < 2.0 × 10-13 cm3 molecule-1 s-1 at 298 K) that reaction with O(1D) is unimportant as an atmospheric removal mechanism for SF5CF3. The kinetics of O(1D) reactions with SO2 (k4) and CS2 (k5) have also been investigated at 298 K. We find that k4 = (2.2 ± 0.3) × 10-10 and k5 = (4.6 ± 0.6) × 10-10 cm3 molecule-1 s-1; branching ratios for reactive quenching are 0.76 ± 0.12 and 0.94 ± 0.06 for the SO2 and CS2 reactions, respectively. All uncertainties reported above are estimates of accuracy (2?) and rate coefficients ki(T) (i = 1,2) calculated from the above Arrhenius expressions have estimated accuracies of ± 15% (2?). PMID:20133693

Zhao, Zhijun; Laine, Patrick L.; Nicovich, J. Michael; Wine, Paul H.

2010-01-01

44

Estimating Surface NO2 and SO2 Mixing Ratios from Fast-Response Total Column Observations and Potential Application to Geostationary Missions  

EPA Science Inventory

Total-column nitrogen dioxide (NO2) data collected by a ground-based sun-tracking spectrometer system 21 (Pandora) and an photolytic-converter-based in-situ instrument collocated at NASA?s Langley Research Center in 22 Hampton, Virginia were analyzed to study the relationship bet...

45

Evaluation of gases, condensates, and SO2 emissions from Augustine volcano, Alaska: the degassing of a Cl-rich volcanic system  

USGS Publications Warehouse

After the March-April 1986 explosive eruption a comprehensive gas study at Augustine was undertaken in the summers of 1986 and 1987. Airborne COSPEC measurements indicate that passive SO2 emission rates declined exponentially during this period from 380??45 metric tons/day (T/D) on 7/24/86 to 27??6 T/D on 8/24/87. These data are consistent with the hypothesis that the Augustine magma reservoir has become more degassed as volcanic activity decreased after the spring 1986 eruption. Gas samples collected in 1987 from an 870??C fumarole on the andesitic lava dome show various degrees of disequilibrium due to oxidation of reduced gas species and condensation (and loss) of H2O in the intake tube of the sampling apparatus. Thermochemical restoration of the data permits removal of these effects to infer an equilibrium composition of the gases. Although not conclusive, this restoration is consistent with the idea that the gases were in equilibrium at 870??C with an oxygen fugacity near the Ni-NiO buffer. These restored gas compositions show that, relative to other convergent plate volcanoes, the Augustine gases are very HCl rich (5.3-6.0 mol% HCl), S rich (7.1 mol% total S), and H2O poor (83.9-84.8 mol% H2O). Values of ??D and ??18O suggest that the H2O in the dome gases is a mixture of primary magmatic water (PMW) and local seawater. Part of the Cl in the Augustine volcanic gases probably comes from this shallow seawater source. Additional Cl may come from subducted oceanic crust because data by Johnston (1978) show that Cl-rich glass inclusions in olivine crystals contain hornblende, which is evidence for a deep source (>25km) for part of the Cl. Gas samples collected in 1986 from 390??-642??C fumaroles on a ramp surrounding the inner summit crater have been oxidized so severely that restoration to an equilibrium composition is not possible. H and O isotope data suggest that these gases are variable mixtures of seawater, FMW, and meteoric steam. These samples are much more H2O-rich (92%-97% H2O) than the dome gases, possibly due to a larger meteoric steam component. The 1986 samples also have higher Cl/S, S/C, and F/Cl ratios, which imply that the magmatic component in these gases is from the more degassed 1976 magma. Thus, the 1987 samples from the lava dome are better indicators than the 1986 samples of degassing within the Augustine magma reservoir, even though they were collected a year later and contain a significant seawater component. Future gas studies at Augustine should emphasize fumaroles on active lava domes. Condensates collected from the same lava-dome fumarole have enrichments ot 107-102 in Cl, Br, F, B, Cd, As, S, Bi, Pb, Sb, Mo, Zn, Cu, K, Li, Na, Si, and Ni. Lower-temperature (200??-650??C) fumaroles around the volcano are generally less enriched in highly volatile elements. However, these lower-termperature fumaroles have higher concentration of rock-forming elements, probably derived from the wall rock. ?? 1990 Springer-Verlag.

Symonds, R.B.; Rose, W.I.; Gerlach, T.M.; Briggs, P.H.; Harmon, R.S.

1990-01-01

46

Polymer-gas reactions (air pollutants: NO2 and SO2) as function of pressure, UV light, temperature, and morphology: A survey  

NASA Technical Reports Server (NTRS)

Reactions of various polymers, such as polystyrene and its stereo-specific isomers, butylrubber, nylon, etc., with nitrogen dioxide and sulfur-dioxide were studied over the past few years. More recently, work has been initiated on the influence of polymer morphology on degradation of polymers in presence of these gases, near UV radiation and oxygen. Unexpected effects have been observed during chain scission near room temperature. Thus, for instance, isotactic polystyrene of various crystallinities, as far as extent and type are concerned, show marked differences in their degradation characteristics. Thus, for instance, crystalline polymers show faster degradation than amorphous ones, which seems to be contrary to expectations. However, this phenomenon can be explained in quite a consistent manner. The importance of all these reactions in connection with air pollution is briefly discussed.

Jellinek, H. H. G.

1972-01-01

47

Mass-transport limitation to the rate of reaction of gases in liquid droplets: application to oxidation of so 2 in aqueous solutions  

Microsoft Academic Search

Aqueous-phase oxidation of SO2 occurs via a sequence of steps consisting of gas-phase diffusion, mass transfer at the gas–water interface, hydrolysis and ionization of the dissolved sulfur-IV, aqueous-phase diffusion, and oxidation reaction. Expressions are given for the characteristic times of these several processes for reaction in aqueous droplets. Readily applicable criteria are developed in terms of these characteristic times to

S. E. Schwartz; J. E. Freiberg

2007-01-01

48

Mineral dust and NOx promote the conversion of SO2 to sulfate in heavy pollution days  

PubMed Central

Haze in China has been increasing in frequency of occurrence as well as the area of the affected region. Here, we report on a new mechanism of haze formation, in which coexistence with NOx can reduce the environmental capacity for SO2, leading to rapid conversion of SO2 to sulfate because NO2 and SO2 have a synergistic effect when they react on the surface of mineral dust. Monitoring data from five severe haze episodes in January of 2013 in the Beijing-Tianjin-Hebei regions agreed very well with the laboratory simulation. The combined air pollution of motor vehicle exhaust and coal-fired flue gases greatly reduced the atmospheric environmental capacity for SO2, and the formation of sulfate was found to be a main reason for the growth of fine particles, which led to the occurrence of haze. These results indicate that the impact of motor vehicle exhaust on the atmospheric environment might be underestimated. PMID:24566871

He, Hong; Wang, Yuesi; Ma, Qingxin; Ma, Jinzhu; Chu, Biwu; Ji, Dongsheng; Tang, Guiqian; Liu, Chang; Zhang, Hongxing; Hao, Jiming

2014-01-01

49

Mineral dust and NOx promote the conversion of SO2 to sulfate in heavy pollution days.  

PubMed

Haze in China has been increasing in frequency of occurrence as well as the area of the affected region. Here, we report on a new mechanism of haze formation, in which coexistence with NOx can reduce the environmental capacity for SO2, leading to rapid conversion of SO2 to sulfate because NO2 and SO2 have a synergistic effect when they react on the surface of mineral dust. Monitoring data from five severe haze episodes in January of 2013 in the Beijing-Tianjin-Hebei regions agreed very well with the laboratory simulation. The combined air pollution of motor vehicle exhaust and coal-fired flue gases greatly reduced the atmospheric environmental capacity for SO2, and the formation of sulfate was found to be a main reason for the growth of fine particles, which led to the occurrence of haze. These results indicate that the impact of motor vehicle exhaust on the atmospheric environment might be underestimated. PMID:24566871

He, Hong; Wang, Yuesi; Ma, Qingxin; Ma, Jinzhu; Chu, Biwu; Ji, Dongsheng; Tang, Guiqian; Liu, Chang; Zhang, Hongxing; Hao, Jiming

2014-01-01

50

Mineral dust and NOx promote the conversion of SO2 to sulfate in heavy pollution days  

NASA Astrophysics Data System (ADS)

Haze in China has been increasing in frequency of occurrence as well as the area of the affected region. Here, we report on a new mechanism of haze formation, in which coexistence with NOx can reduce the environmental capacity for SO2, leading to rapid conversion of SO2 to sulfate because NO2 and SO2 have a synergistic effect when they react on the surface of mineral dust. Monitoring data from five severe haze episodes in January of 2013 in the Beijing-Tianjin-Hebei regions agreed very well with the laboratory simulation. The combined air pollution of motor vehicle exhaust and coal-fired flue gases greatly reduced the atmospheric environmental capacity for SO2, and the formation of sulfate was found to be a main reason for the growth of fine particles, which led to the occurrence of haze. These results indicate that the impact of motor vehicle exhaust on the atmospheric environment might be underestimated.

He, Hong; Wang, Yuesi; Ma, Qingxin; Ma, Jinzhu; Chu, Biwu; Ji, Dongsheng; Tang, Guiqian; Liu, Chang; Zhang, Hongxing; Hao, Jiming

2014-02-01

51

40 CFR 60.42b - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2011 CFR

...shall cause to be discharged into the atmosphere any gases that contain SO2 in excess...shall cause to be discharged into the atmosphere any gases that contain SO2 in excess...shall cause to be discharged into the atmosphere any gases that contain SO2 in...

2011-07-01

52

New discoveries enabled by OMI SO2 measurements and future missions  

NASA Astrophysics Data System (ADS)

The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. This talk highlights most recent science results enabled by using OMI SO2 data. OMI daily contiguous volcanic SO2 data continue 25+ climatic record by its predecessors (Total Ozone mapping Spectrometers 1978-2005), but higher SO2 sensitivity allows measuring volcanic plumes for a longer time as well as measuring passive volcanic degassing from space. New algorithm development allows direct estimating of SO2 plume heights to refine SO2 tonnages in largest volcanic plumes important for climate applications. Quantitatively, anthropogenic SO2 is more difficult to measure from space, since ozone absorption and Rayleigh scattering reduce sensitivity to pollutants in the lower troposphere. OMI data first enabled daily detection of SO2 burdens from individual smelters as well as observed SO2 pollution lofting from boundary layer and long-range transport in free troposphere. Interplay between volcanic and anthropogenic SO2 emissions resulted in highly variable SO2 pollution levels in Peru and Mexico City. We have updated our copper smelter analysis, which showed interesting new trends. Combining OMI data with trajectory models and aerosol/cloud measurements by A-train sensors (MODIS, CALIPSO) allowed tracking long-range transport of volcanic and anthropogenic aerosol/SO2 plumes. These studies placed new constraints on conversion rates of SO2 to sulfate at different heights from free troposphere to the lower stratosphere. We describe new techniques for spatial and time averaging that have been used to determine the global distribution of anthropogenic SO2 burdens, and the efficacy of abatement strategies. OMI seasonal to multi-year average images clearly show the world-highest consistent SO2 pollution in eastern China, mostly due to the burning of high-sulfur coal in its many coal-fired power plants. Recently, China's government has instituted nationwide measures to control SO2 emissions through the adoption of flue-gas desulfurization technology (FGD) on new power plants; and even greater measures were adopted in the Beijing area in anticipation of the Olympic Games. We demonstrate that the OMI can pick up both SO2 and NO2 emissions from large point sources in northern China, where large increases in both gases were observed from 2005 to 2007, over areas with newly established power plants. The OMI SO2/NO2 ratio generally agrees with the estimated emission factors for coal-fired power plants based on a bottom-up approach. Between 2007 and 2008, OMI detected little change in NO2 but dramatic decline in SO2 over the same areas. While the almost constant NO2 levels between the two years imply steady electricity generation from the power plants, the large reduction in SO2 confirms the effectiveness of the FGD units, which likely became operational between 2007 and 2008. Further development of satellite detection and monitoring of point pollution sources requires better than 10km ground resolution. We show how planned Dutch /ESA TROPOMI and NASA GEOCape missions will advance the art of measuring point source emissions in coming decade.

Krotkov, Nickolay

2010-05-01

53

Flux calculation using CARIBIC DOAS aircraft measurements: SO2 emission of Norilsk  

NASA Astrophysics Data System (ADS)

Based on a case-study of the nickel smelter in Norilsk (Siberia), the retrieval of trace gas fluxes using airborne remote sensing is discussed. A DOAS system onboard an Airbus 340 detected large amounts of SO2 and NO2 near Norilsk during a regular passenger flight within the CARIBIC project. The remote sensing data were combined with ECMWF wind data to estimate the SO2 output of the Norilsk industrial complex to be around 1 Mt per year, which is in agreement with independent estimates. This value is compared to results using data from satellite remote sensing (GOME, OMI). The validity of the assumptions underlying our estimate is discussed, including the adaptation of this method to other gases and sources like the NO2 emissions of large industries or cities.

Walter, D.; Heue, K.-P.; Rauthe-SchöCh, A.; Brenninkmeijer, C. A. M.; Lamsal, L. N.; Krotkov, N. A.; Platt, U.

2012-06-01

54

Real-time measurement of reactive gases (NO, NO2, O3, CO) at ERSA, Cape Corsica, a long term Observatory.  

NASA Astrophysics Data System (ADS)

Important efforts have been put in 2012 in order to implement the infrastructure and instrumentation for a fully equipped background monitoring station at Ersa, Cape Corsica, key location at the crossroads of dusty southerly airmasses and polluted outflows from the European continent. The ERSA observatory is a french initiative within the framework of CHARMEX (Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/) and CORSICA (Centre d'Observation Régional pour la Surveillance du Climat et de l'environnement Atmosphérique et océanographique en Méditerranée occidentale (http://www2.obs-mip.fr/corsica) . The measurements of the station include real-time measurement of reactive gases (O3, CO, NO, NO2), off-line VOC measurements (cylinders, cartridges), a broad spectrum of aerosol properties (chemical composition, ground optical properties, integrated and space-resolved optical properties , size distribution properties, mass, hygroscopicity as well as dry/wet depositions). Among all the parameters, reactive gases are recognized as precursors of ozone and aerosol. The primarily emitted nitrogen oxides (NOx=NO+NO2) have a substantial impact on radical chemistry, ozone (O3) formation and aerosol by their atmospheric oxidation to aerosol nitrate. Carbon monoxide (CO) is mostly primarily emitted from combustion processes, but it is also formed in substantial amounts from the oxidation of methane (CH4) and volatile organic compounds (VOCs). Due to its high global turn-over rates CO is a major O3 precursor, and it has a strong impact on the oxidizing capacity and thus indirectly on the concentration of the climate gas CH4. O3 is a climate gas itself, however, also strongly involved in NO/NO2 partitioning and oxidizing capacity, thus coupling back on several photochemical processes. Accordingly, impacts on climate are multiple and rather complex. The understanding requires high quality, long-term observations of these reactive species. We present here the first measurement of reactive gases (O3, CO, NO, NO2) obtained at ERSA, the new monitoring station at Cape Corsica.

Pichon, Jean-Marc; Colomb, Aurelie; Gheusi, Francois; Sauvage, Stephane; Pont, Veronique; Tison, Emmanuel; Bordier, Florent; Grignion, Guillaume; Savelli, Jean-Luc; Dulac, Francois; Sciare, Jean; Nicolas, Jose; Bourrianne, Thierry; Bouvier, Laetitia

2013-04-01

55

Flux calculation using CARIBIC DOAS aircraft measurements - SO2 emission of Norilsk  

NASA Astrophysics Data System (ADS)

Based on a case-study of the nickel smelter in Norilsk (Siberia), the retrieval of trace gas fluxes using airborne remote sensing is discussed. CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container, www.caribic.de) observes physical and chemical processes in the atmosphere using a fully automated measurement container aboard a Lufthansa Airbus 340-600. A special inlet system is mounted on the aircraft with probes for trace gases, water vapor and aerosol particles. The inlet system also includes DOAS (Differential Optical Absorption Spectroscopy) telescopes for remote sensing. In October 2010, enhanced NO2 and high SO2 Slant Column Densities up to 6 · 1017 molec/cm2 were detected near Norilsk with the nadir channel of the DOAS instrument. The retrieved column densities were combined with ECMWF wind data to derive the SO2 flux crossing the vertical plane of the flight route. With that, the SO2 output of the Norilsk industrial complex is estimated to be ~1 Mt per year, which is in agreement with various independent estimates. We also compare our value to results obtained using data from satellite remote sensing (GOME-2, OMI). The validity of the assumptions we used to obtain our estimate is discussed. We also discuss the adaption of our method to other gases and sources like the NO2 emissions of industrial complexes or major cities.

Walter, D.; Heue, K.-P.; Rauthe-Schöch, A.; Brenninkmeijer, C. A. M.; Lamsal, L. N.; Krotkov, N. A.; Platt, U.

2012-04-01

56

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2  

Microsoft Academic Search

Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is

I. J. Simpson; N. J. Blake; B. Barletta; G. S. Diskin; H. E. Fuelberg; K. Gorham; L. G. Huey; S. Meinardi; F. S. Rowland; S. A. Vay; A. J. Weinheimer; M. Yang; D. R. Blake

2010-01-01

57

Chapter 4 The Gaseous State Chemistry of Gases  

E-print Network

Chapter 4 The Gaseous State NO2 #12;AIR #12;Chemistry of Gases SO3 .. corrosive gas SO2...burning) ~1760 Charle The definition of the Temperature All gases expand with increasing temperature by the same extent. t = c [(V/V0)-1] for all gases 1802 Gay-Lussac reproted c of 267 oC later refined to be c = 273

Ihee, Hyotcherl

58

SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES  

Microsoft Academic Search

It is well known that natural and synthetic zeolites (molecular sieves) can adsorb gaseous SO2<\\/sub> from flue gas and do it more efficiently than lime based scrubbing materials. Unfortunately their cost ($500-$800 per ton) has deterred their use in this capacity. It is also known that zeolites are easy to synthesize from a variety of natural and man-made materials. The

MICHAEL GRUTZECK

1998-01-01

59

SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES  

Microsoft Academic Search

It is well known that natural and synthetic zeolites (molecular sieves) can adsorb gaseous SOâ from flue gas and do it more efficiently than lime based scrubbing materials. Unfortunately their cost ($500-$800 per ton) has deterred their use in this capacity. It is also known that zeolites are easy to synthesize from a variety of natural and man-made materials. The

Michael Grutzeck

1999-01-01

60

SO(2) Removal from Flue Gases Using Uutility Synthesized Zeolites  

SciTech Connect

Historically, sulfur dioxide (SO{sub 2}) emissions were unregulated. As the environmental consequences of such emissions began to surface, increasingly stringent, federal and state government mandated pollution control requirements were imposed on the electric power generating industry. Coal burning utilities were forced to make one of two dioices. They could install flue gas scrubbing equipment or start to burn lower sulfur containing coal. The proposed research is directed at those utilities that have made the second choice, or utilities desiring to undertake new plant construction.

Grutzeck, M.

1997-03-31

61

MODELING OF SO2 OXIDATION IN SMOG  

EPA Science Inventory

Smog chamber experiments were conducted to investigate the (1) kinetics of free radical reactions of SO2 in smog and (2) SO2 transformation to sulfate for atmospheric simulations. Rate constants were derived for the following reactions: SO2+HO+M yields sulfate (60), SO2+HO2 yield...

62

Simultaneous treatment of NO and SO2 with aqueous NaClO2 solution in a wet scrubber combined with a plasma electrostatic precipitator.  

PubMed

NO and SO2 gases that are generally produced in thermal power plants and incinerators were simultaneously removed by using a wet scrubber combined with a plasma electrostatic precipitator. The wet scrubber was used for the absorption and oxidation of NO and SO2, and non-thermal plasma was employed for the electrostatic precipitation of aerosol particles. NO and SO2 gases were absorbed and oxidized by aerosol particles of NaClO2 solution in the wet scrubber. NO and SO2 reacted with the generated NaClO2 aerosol particles, NO2 gas, and aqueous ions such as NO2(-), NO3(-), HSO3(-), and SO4(2-). The aerosol particles were negatively charged and collected on the surface of grounded anode in the plasma electrostatic precipitator. The NO and SO2 removal efficiencies of the proposed system were 94.4% and 100% for gas concentrations of 500mg/m(3) and a total gas flow rate of 60Nm(3)/h, when the molar flow rate of NaClO2 and the gas-liquid contact time were 50mmol/min and 1.25s, respectively. The total amount and number of aerosol particles in the exhaust gas were reduced to 7.553?g/m(3) and 210/cm(3) at the maximum plasma input power of 68.8W, which are similar to the values for clean air. PMID:25497024

Park, Hyun-Woo; Choi, Sooseok; Park, Dong-Wha

2015-03-21

63

On the SO2 problem of solid fuel combustion  

NASA Astrophysics Data System (ADS)

Many companies use two-phase absorbents (CaCO3 suspension) for waste gases purification from SO2. A qualitative theoretical analysis of the absorption kinetics in the cases of two-phase absorbent, using the convection-diffusion type of model, is presented. It is shown that the low CaCO3 concentration lead to very small chemical reaction rate and as a result the absorption rate is limited by the physical absorption of SO2 in water, i.e. the process efficiency is very small. An average concentration model for quantitative analysis of the absorption process and an iterative numerical algorithm for the model equations solution is proposed.

Boyadjiev, Chr.

2014-09-01

64

STATUS OF SO2 SCRUBBING TECHNOLOGIES  

EPA Science Inventory

The paper presents the extent of current sulfur dioxide (SO2) scrubber applications on electricity generating units in the U.S. and abroad. The technical performance of recent SO2 scrubber installations is discussed. Recently reported technical innovations to SO2 scrubbing tech...

65

Retrieval and validation of surface SO2 from OMI SO2 columns over China  

NASA Astrophysics Data System (ADS)

There is concern about the impact of near-surface SO2 on human health and ecosystems over China. Remote sensing technology provides an unprecedented tool for continuous and real-time monitoring for atmospheric SO2. In this paper, we used the SO2 vertical profile from multi-scale air quality model system RAMS-CMAQ model, to get near-surface SO2 concentrations from OMI observations. And then the ground-based SO2 Air Pollution Index (API) data were used to estimate the effectiveness of the near-surface SO2 concentrations obtained from OMI SO2 columns. Results show that, (1) SO2 columns from RAMS-CMAQ model have good correlation with the near-surface SO2 concentrations (correlation coefficient R reaching to 0.73); (2) the near-surface SO2 concentrations, which are derived by combining the OMI SO2 columns and RAMS-CMAQ SO2 profile, have a higher correlation (R=0.592) with ground-based SO2 API than OMI SO2 columns (R=0.271) and RAMS-CMAQ near-surface SO2 concentrations (R=0.306). The present findings improve our understanding of SO2 air pollution over China, and also have contributed to the near-surface SO2 retrieval studies.

Yan, H.; Wang, W.; Chen, L.

2013-12-01

66

New developments to improve SO2 cameras  

NASA Astrophysics Data System (ADS)

The SO2 camera is a remote sensing instrument that measures the two-dimensional distribution of SO2 (column densities) in volcanic plumes using scattered solar radiation as a light source. From these data SO2-fluxes can be derived. The high time resolution of the order of 1 Hz allows correlating SO2 flux measurements with other traditional volcanological measurement techniques, i.e., seismology. In the last years the application of SO2 cameras has increased, however, there is still potential to improve the instrumentation. First of all, the influence of aerosols and ash in the volcanic plume can lead to large errors in the calculated SO2 flux, if not accounted for. We present two different concepts to deal with the influence of ash and aerosols. The first approach uses a co-axial DOAS system that was added to a two filter SO2 camera. The camera used Filter A (peak transmission centred around 315 nm) to measures the optical density of SO2 and Filter B (centred around 330 nm) to correct for the influence of ash and aerosol. The DOAS system simultaneously performs spectroscopic measurements in a small area of the camera's field of view and gives additional information to correct for these effects. Comparing the optical densities for the two filters with the SO2 column density from the DOAS allows not only a much more precise calibration, but also to draw conclusions about the influence from ash and aerosol scattering. Measurement examples from Popocatépetl, Mexico in 2011 are shown and interpreted. Another approach combines the SO2 camera measurement principle with the extremely narrow and periodic transmission of a Fabry-Pérot interferometer. The narrow transmission window allows to select individual SO2 absorption bands (or series of bands) as a substitute for Filter A. Measurements are therefore more selective to SO2. Instead of Filter B, as in classical SO2 cameras, the correction for aerosol can be performed by shifting the transmission window of the Fabry-Pérot interferometer towards the SO2 absorption cross section minima. A correction of ash and aerosol influences with this technique can decrease deviation from the true column by more than 60%, since the wavelength difference between the two measurement channels is much smaller than in classical SO2 cameras. While the implementation of this approach for a 2D camera encompasses many challenges, it gives the possibility to build a relatively simple and robust scanning instrument for volcanic SO2 distributions. A second problem of the SO2 camera technique is the relatively high price, which prevents its use in many volcano observatories in developing countries. Most SO2 cameras use CCDs that were originally designed for astronomical purposes. The large pixel size and low noise of these detectors compensates for the low intensity of solar radiation in the UV and the low quantum efficiency of the detector in this spectral range. However, the detectors used cost several thousand US dollars. We present results from test measurements using a consumer DSLR camera as a detector of an SO2 camera. Since the camera is not sensitive in the UV, the incoming radiation is first imaged onto a screen that is covered with a suitable fluorescent dye converting the UV radiation to visible light.

Luebcke, P.; Bobrowski, N.; Hoermann, C.; Kern, C.; Klein, A.; Kuhn, J.; Vogel, L.; Platt, U.

2012-12-01

67

SO2 removal with ferric sulfate solution.  

PubMed

The determination of the influence of the concentration of ferric sulfate solution on SO2 absorption was performed in this study. It was found that the SO2 absorption efficiency increased with increasing ferric concentration, and decreased with the acidity of the spraying solution. As the hydrolysis of ferric ions occurs in solution, the SO2 removal efficiency increased slowly with increasing Fe(III) concentration. Taking into account the hydrodynamic and mass transfer characteristics of the packed column, the enhancement factor (E) was found to depend on the concentration of the ferric ions and pH, which indicated that it could be used for the simulation or design of SO2 scrubbers. PMID:18619149

Jiang, J-H; Yan, H; Li, Y-H; Xie, W-J; Li, L-H; Cai, W-M

2008-04-01

68

Transport of Cerro Hudson SO2 clouds  

Microsoft Academic Search

The Cerro Hudson volcano in southern Chile (45.92°S, 73.0°W) emitted large ash and sulfur dioxide clouds on August 12-15, following several days of minor activity [Global Volcanism Network Bulletin, 1991]. The SO2 clouds were observed using (preliminary) near real-time data from the Total Ozone Mapping Spectrometer (TOMS) as they encircled the south polar region. The injection of SO2 into the

Scott D. Doiron; Gregg J. S. Bluth; Charles C. Schnetzler; Arlin J. Krueger; Louis S. Walter

1991-01-01

69

Interspecific Variation in SO2 Flux 1  

PubMed Central

The objective of this study was to clarify the relationships among stomatal, residual, and epidermal conductances in determining the flux of SO2 air pollution to leaves. Variations in leaf SO2 and H2O vapor fluxes were determined using four plant species: Pisum sativum L. (garden pea), Lycopersicon esculentum Mill. flacca (mutant of tomato), Geranium carolinianum L. (wild geranium), and Diplacus aurantiacus (Curtis) Jeps. (a native California shrub). Fluxes were measured using the mass-balance approach during exposure to 4.56 micromoles per cubic meter (0.11 microliters per liter) SO2 for 2 hours in a controlled environmental chamber. Flux through adaxial and abaxial leaf surfaces with closed stomata ranged from 1.9 to 9.4 nanomoles per square meter per second for SO2, and 0.3 to 1.3 millimoles per square meter per second for H2O vapor. Flux of SO2 into leaves through stomata ranged from ?0 to 8.5 (dark) and 3.8 to 16.0 (light) millimoles per square meter per second. Flux of H2O vapor from leaves through stomata ranged from ?0 to 0.6 (dark) to 0.4 to 0.9 (light) millimole per square meter per second. Lycopersicon had internal flux rates for both SO2 and H2O vapor over twice as high as for the other species. Stomatal conductance based on H2O vapor flux averaged from 0.07 to 0.13 mole per square meter per second among the four species. Internal conductance of SO2 as calculated from SO2 flux was from 0.04 mole per square meter per second lower to 0.06 mole per square meter per second higher than stomatal conductance. For Pisum, Geranium, and Diplacus stomatal conductance was the same or slightly higher than internal conductance, indicating that, in general, SO2 flux could be predicted from stomatal conductance for H2O vapor. However, for the Lycopersicon mutant, internal leaf conductance was much higher than stomatal conductance, indicating that factors inside leaves can play a significant role in determining SO2 flux. PMID:16664551

Olszyk, David M.; Tingey, David T.

1985-01-01

70

Adsorption and Reaction of CO2 and SO2 at a Water Surface Teresa L. Tarbuck and Geraldine L. Richmond*  

E-print Network

(acid-base equilibria). The dominant reaction product (SO2(aq), HSO3 -, or SO3 2-) depends on the pAdsorption and Reaction of CO2 and SO2 at a Water Surface Teresa L. Tarbuck and Geraldine L into the adsorption and reactions of these gases in atmospheric aerosols. The results show that an SO2 surface complex

Richmond, Geraldine L.

71

Application of Aura/OMI PBL SO2 product for estimating SO2 emissions  

E-print Network

Application of Aura/OMI PBL SO2 product for estimating SO2 emissions and future enhancements from new satellite missions 1 N. Krotkov, 2 V. Fioletov, 3,1 K. Yang, 4,1 Can Li, 3 R. Dickerson & Aura/OMI Monitoring Instrument (OMI) continues 30+ year O3 and SO2 records · Launched on NASA EOS Aura platform

Jacob, Daniel J.

72

MERCURY SPECIATION IN COMBUSTION SYSTEMS: STUDIES WITH SIMULATED FLUE GASES AND MODEL FLY ASHES  

EPA Science Inventory

The paper gives results of a bench-scale study of the effects of flue gas and fly ash parameters on the oxidation of elemental mercury in simulated flue gases containing hydrogen chloride (HCl), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and water vapor (H2O...

73

SO2 SCRUBBING TECHNOLOGIES: A REVIEW  

EPA Science Inventory

Electricity generating units may use sulfur dioxide (SO2) scrubbers to meet the requirements of Phase II of the Acid Rain S02 Reduction Program. Additionally, the use of scrubbers can result in reduction of mercury emissions. It is timely, therefore, to review the commercially av...

74

Reduction of SO2 and Particulate Emissions  

NSDL National Science Digital Library

The Sofia Institute on Local Air Quality is part of the Regional Environmental Center (REC) for Central and Eastern Europe. Its report, Reduction of SO2 and Particulate Emissions, provides both emission data and the legal framework surrounding the reduction of emissions. The report is available either online or as a [.pdf] file.

1998-01-01

75

ADVANCED CONCEPTS: SO2 REMOVAL PROCESS IMPROVEMENTS  

EPA Science Inventory

The report gives results of a study of a potassium scrubbing system that recovers useful forms of sulfur from pollutants while using a low-energy process to regenerate the absorbing medium. The report also describes two versions of a new, regenerable process for SO2 scrubbing tha...

76

SO2 EMISSIONS AND TIME SERIES MODELS  

EPA Science Inventory

The paper describes a time series model that permits the estimation of the statistical properties of pounds of SO2 per million Btu in stack emissions. It uses measured values for this quantity provided by coal sampling and analysis (CSA), by a continuous emissions monitor (CEM), ...

77

Copper oxide aerosol: reaction with SO 2  

NASA Astrophysics Data System (ADS)

Copper oxide aerosol and SO 2 are emitted concurrently from copper smelters. The reactions between copper oxide aerosol and SO 2 could result in the formation of irritant sulfur oxides on the surface of the particles that could affect smelter workers or residents living near the smelter. In this study, we investigate the reactions of an ultrafine copper oxide aerosol (count median diameter = 0.03 ?m) and SO 2. In a dry furnace, two S(IV) species were formed as determined using x-ray photoelectron spectroscopy. One S(IV) corresponds to ionic S(IV) with a binding energy of 166.8 eV. The other corresponds to adsorbed S(IV) with a binding energy of 168.4eV. Increasing relative humidity (r.h.) in the mixing chamber to 78% promotes the formation of S(VI). Addition of water vapor into the hot zone of the furnace leads to the formation of only S(VI) on the aerosol and this is not affected by the r.h. in the mixing chamber. Sputtering of the sample by an Ar + beam revealed that these sulfur oxides were on the surface of the aerosol. The concentrations of total S on the particles in the exposure chamber as determined using a flame photometric detector system were 0.24, 0.47 and 0.58 ?mole S m-3 for the mixing conditions of dry furnace, dry furnace with high r.h. and water in the furnace with high humidity, respectively.

Chen, L. C.; Peoples, S. M.; McCarthy, J. F.; Amdur, M. O.

78

SO(2, 3) noncommutative gravity model  

NASA Astrophysics Data System (ADS)

In this paper the noncommutative gravity is treated as a gauge theory of the non-commutative SO(2, 3)? group, while the noncommutativity is canonical. The Seiberg-Witten (SW) map is used to express noncommutative fields in terms of the corresponding commutative fields. The commutative limit of the model is the Einstein-Hilbert action plus the cosmological term and the topological Gauss-Bonnet term. We calculate the second order correction to this model and obtain terms that are zeroth, first, ... and fourth power of the curvature tensor. Finally, we discuss physical consequences of those correction terms in the limit of big cosmological constant.

Dimitrijevi?, M.; Radovanovi?, V.

2014-12-01

79

Monitoring of volcanic SO2 emissions using the GOME-2 instrument  

NASA Astrophysics Data System (ADS)

This contribution focusses on the GOME-2 SO2 column products from the METOP-A and B satellites. The GOME-2 SO2 column product has been developed in the framework of EUMETSAT's Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M-SAF). Satellite-based remote sensing measurements of volcanic SO2 provide critical information for reducing volcanic hazards. Volcanic eruptions may bring ash and gases (e.g. SO2) high up into the atmosphere, where a long-range transport can occur. SO2 is an important indicator for volcanic activity and an excellent tracer for volcanic eruption clouds, especially if ash detection techniques fail. SO2 can affect aviation safety: In the cabin it can cause disease and respiratory symptoms, whereas in its hydrogenated form H2SO4 it is highly corrosive and can cause damage to jet engines as well as pitting of windscreens. We will present results for volcanic events retrieved from GOME-2 solar backscattered measurements in the UV wavelength region around 320nm using the Differential Optical Absorption Spectroscopy (DOAS) method. SO2 columns are generated operationally by DLR with the GOME Data Processor (GDP) version 4.7 and are available in near-real-time, i.e. within two hours after sensing. Using data from both MetOp satellites allows for a daily global coverage. We will furthermore present current improvements to the GOME-2 SO2 column product.

Hedelt, Pascal; Valks, Pieter; Loyola, Diego

2014-05-01

80

A thermodynamic analysis of the SO2/H2SO4 system in SO2-depolarized electrolysis  

E-print Network

A thermodynamic analysis of the SO2/H2SO4 system in SO2-depolarized electrolysis Maximilian B) and a catalyst. The second reaction, the SO2-depolarized electrolysis of water, * Corresponding author. Tel.: þ1

Weidner, John W.

81

Synthetic Assessment of Historical Anthropogenic Sulfur Dioxide (SO2) Emissions  

E-print Network

Synthetic Assessment of Historical Anthropogenic Sulfur Dioxide (SO2) Emissions Zhibek Issakyzy, Mentor: Xiaoshi Xing, CIESIN Columbia University. The Earth Institute. What is SO2? Sulfur Dioxide (SO2 atmosphere and climate. Sulfur Dioxide (SO2) is one of the pollutants responsible for the environmental

82

Satellite-based constraints on tropospheric volcanic emissions of SO2 and CO2  

NASA Astrophysics Data System (ADS)

There is considerable motivation to improve constraints on global volcanic CO2 emissions, and their partitioning between summit plumes and diffuse flank degassing; both for volcano monitoring and to better understand the role of volcanism in the global carbon cycle. One approach to refining plume CO2 degassing budgets for persistently degassing volcanoes is to obtain more accurate constraints on SO2 emissions and SO2/CO2 ratios in volcanic gases. The current generation of space-borne, hyperspectral ultraviolet (UV) nadir mapping instruments have afforded tremendous insights into the spatial and temporal variability of global, subaerial volcanic degassing of SO2. We use ~8 years of daily SO2 measurements by the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite to identify and rank the strongest volcanic SO2 sources of the past decade, and compare the results to existing emissions inventories. Major SO2 sources include Ambrym (Vanuatu), Nyiragongo (DR Congo) and several volcanoes in Indonesia and Kamchatka that are largely absent from existing inventories. Typical SO2 emission rates are estimated based on the SO2 column amounts measured in the volcanic plumes. Based on this improved satellite-derived SO2 emissions inventory and existing data on SO2/CO2 ratios, we can refine estimates of plume CO2 emissions for the most prominent volcanic gas emitters. We have also used the OMI SO2 measurements to select volcanic targets for special 'stare-mode' observations of the Japanese Greenhouse Gases Observing Satellite (GOSAT) since summer 2010, to assess the potential of GOSAT shortwave-infrared (SWIR) reflectance data for detection of volcanic CO2 emissions. GOSAT measures the column-average CO2 mixing ratio (or CO2 total column) with a spatial resolution of 10 km, and hence the signal is dominated by ambient atmospheric CO2 and any seasonal cycle thereof. Further complications for volcano monitoring are that GOSAT SWIR measurements are subject to interference by clouds and aerosol (ubiquitous at most active volcanoes) and mostly collected over land under clear sky conditions. By repeatedly pointing the GOSAT FOV at known, strong point sources of volcanic degassing, we are accumulating a statistically significant dataset to evaluate whether space-based detection of volcanic CO2 is feasible using current assets, to provide data for further, detailed spectral analysis, and to assess the potential of future satellite missions such as the Orbiting Carbon Observatory-2 (OCO-2) for volcanic CO2 detection.

Carn, S. A.; Schwandner, F. M.

2012-12-01

83

Relative Sensitivity of Wetland Plants to SO 2 Pollution  

Microsoft Academic Search

Sulfur dioxide (SO2) is a major air pollutant and its concentration is increasing in many metropolitan and industrial areas. Identification of\\u000a SO2 tolerant species that can be used in wetland plantings in those areas is needed. We compared SO2 toxicity and tolerance in 16 wetland herbaceous plants by examining SO2 effects on their photosynthetic apparatus. After leaf sections had been

Chenyan Sha; Tianhui Wang; Jianjian Lu

2010-01-01

84

HISTORIC SO2 AND NOX EMISSIONS ESTIMATES (FOR MICROCOMPUTERS)  

EPA Science Inventory

The data file contains the results of a comparison of historic SO2 and NOx emission data sets. The diskette contains 12 files: AL-FLSO2.WK1 SO2 emissions for Alabama-Florida + U.S.; GA-LASO2.WK1 SO2 emissions for Georgia-Louisiana; ME-MTSO2.WK1 SO2 emissions for Maine-Montana; NE...

85

Solubilities and thermodynamic properties of SO2 in ionic liquids.  

PubMed

Task-specific ionic liquids (TSILs) have been experimentally demonstrated to absorb more sulfur dioxide (SO(2)) than normal ILs from gas mixtures with low SO(2) concentrations; however, the differences of SO(2) solubilities in the two kinds of ILs at given temperatures and pressures have not been studied systematically. Moreover, the mechanism of the interaction between SO(2) and ILs still remains unclear. In this work, the solubilities of SO(2) in TSILs (1,1,3,3-tetramethylguanidinium lactate and monoethanolaminium lactate) and normal ILs (1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate) were determined. The solubilities of SO(2) are correlated by a modified Redlich-Kwong equation of state (RK EoS). The chemical absorption and physical absorption are differentiated, and the absorption mechanism has been proposed with the aid of the modified RK EoS. SO(2) absorption capacity in TSILs is contributed from both chemical interaction and physical interaction. Two TSIL molecules chemically absorb one SO(2) molecule, and the chemical absorption amount follows the chemical equilibrium. Normal ILs only physically absorb SO(2) following Henry's law. The chemical equilibrium constant, reaction enthalpy, Gibbs energy of reaction, reaction entropy, and Henry's law constant of SO(2) absorbed in ILs have been calculated. The present model can predict SO(2) absorption capacity for capture and SO(2) equilibrium concentration in IL for recovery. PMID:21542571

Jin, Meijin; Hou, Yucui; Wu, Weize; Ren, Shuhang; Tian, Shidong; Xiao, Li; Lei, Zhigang

2011-05-26

86

COAL CLEANING OPTIONS FOR SO2 EMISSION REDUCTION  

EPA Science Inventory

The article discusses coal cleaning options for reducing SO2 emissions. Conventional PCC can reduce the potential SO2 emission from high sulfur coal by 20-50%, depending on the inherent properties of individual coals. SO2 emission reduction by conventional PCC is limited by the a...

87

BrO/SO2 studies at Mt. Etna during 2006 and 2007  

NASA Astrophysics Data System (ADS)

In 2006 and 2007 during a series of different volcanic activities of Mt. Etna, including Lava flows strombolian explosions, Lava fountains, field studies, focusing on halogen oxides and sulphur dioxide emissions, were taking place with a scanning- as well as with a mobile-DOAS instrument. The Differential Optical Absorption Spectroscopy (DOAS) is an optical remote sensing technique and can simultaneously measure several trace gases. A BrO/SO2 time series from a fixed distance at 6 km from the emission source and gas emissions close to the different main craters and above lava flows were studied with the scanning DOAS instrument. In the same time period sulphur dioxide flux measurements were frequently carried out with a mobile-DOAS instrument at Mt. Etna during different states of volcanic activity. The SO2 fluxes varied between 194 t/d and 8800 t/d. The BrO/SO2 ratio showed peak three moth before the eruption started and the changes were not directly correlated to the changes in SO2 fluxes and therefore could provide additional information of the volcanic system. The BrO/SO2 ratio, a minimal bromine flux itself, which was calculated by using simultaneously measured SO2 fluxes, are presented in the context of the changing activity during the Mt. Etna 2006 eruption and the year 2007.

Giuffrida, G. B.; Bobrowski, N.; Vita, F.; Sollami, A.; Inguaggiato, S.

2007-12-01

88

SO2 and NOx conversion rates in the Kuwait oil fire smoke plume  

NASA Astrophysics Data System (ADS)

Aircraft measurements of the Kuwait oil fire smoke plumes during August 1991 are examined to estimate the conversion rates of SO2 and NOx (NO+NO2) to sulfate and nitrate, respectively. A method based on evaluating a Lagrangian mass conservation equation for the ratios of SO2 and NOx to CO2 is used to estimate plume dilution and conversion rates. The loss process is expressed as first and second order, and NOx concentration serves as a surrogate for the oxidizing species in the second-order reaction. Continuous measurements of SO2 and NOx within the smoke plume indicate that SO2 and NOx conversion rates were approximately 1% h-1 and 2% h-1, respectively, 100 km from the sources; further downwind, both conversion rates decreased. A box model is used to simulate the chemistry in the plume; SO2 and NOx conversion rates predicted by the box model were ?1% h-1 and 2% to 30% h-1, respectively, depending on time of day and distance from the source. The dependence of the modeled conversion rate on the time of day suggests that the conversion of SO2 and NOx calculated from the field data may be the average conversion rate associated with nighttime and early-morning chemistry.

Smyth, Scott B.; Peters, Leonard K.; Berkowitz, Carl M.; Daum, Peter H.; Rodgers, Michael O.

1994-08-01

89

Observations of atmospheric trace gases by MAX-DOAS in the coastal boundary layer over Jiaozhou Bay  

NASA Astrophysics Data System (ADS)

Atmospheric trace gases exist in the atmosphere of the earth rarely. But the atmospheric trace gases play an important role in the global atmospheric environment and ecological balance by participating in the global atmospheric cycle. And many environmental problems are caused by the atmospheric trace gases such as photochemical smog, acid rain, greenhouse effect, ozone depletion, etc. So observations of atmospheric trace gases become very important. Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) developed recently is a kind of promising passive remote sensing technology which can utilize scattered sunlight received from multiple viewing directions to derive vertical column density of lower tropospheric trace gases like ozone, sulfur dioxide and nitrogen dioxide. It has advantages of simple structure, stable running, passive remote sensing and real-time online monitoring automatically. A MAX-DOAS has been developed at Shandong Academy of Sciences Institute of Oceanographic Instrumentation (SDIOI) for remote measurements of lower tropospheric trace gases (NO2, SO2, and O3). In this paper, we mainly introduce the stucture of the instrument, calibration and results. Detailed performance analysis and calibration of the instrument were made at Qingdao. We present the results of NO2, SO2 and O3 vertical column density measured in the coastal boundary layer over Jiaozhou Bay. The diurnal variation and the daily average value comparison of vertical column density during a long-trem observation are presented. The vertical column density of NO2 and SO2 measured during Qingdao oil pipeline explosion on November 22, 2013 by MAX-DOAS is also presented. The vertical column density of NO2 reached to a high value after the explosion. Finally, the following job and the outlook for future possible improvements are given. Experimental calibration and results show that the developed MAX-DOAS system is reliable and credible.

Li, Xianxin; Wang, Zhangjun; Meng, Xiangqian; Zhou, Haijin; Du, Libin; Qu, Junle; Chen, Chao; An, Quan; Wu, Chengxuan; Wang, Xiufen

2014-11-01

90

Space-borne constraints on SO2 fluxes for recent volcanic eruptions in 2011  

NASA Astrophysics Data System (ADS)

Magmatic gases (H2O, CO2, sulphur and halogenated species) are the driving forces of volcanic eruptions. These emissions can strongly impact the local biosphere (through acid deposition) and also affect significantly the chemical composition of the atmosphere and climate. Sulphur dioxide (SO2) measurements have been used to characterize and monitor volcanic activity for decades. However, remote-sensing methods based on absorption spectroscopy generally provide integrated concentration of already dispersed plumes of SO2. In the last years, consolidated measurements of total emission fluxes of SO2 have been made possible for active degassing volcanoes using ground-based measurements. For non-monitored volcanoes or explosive volcanic eruptions, space-based measurements of SO2 are more adequate but unfortunately fluxes estimates are sparse. The motivation for this study is an effort to constrain volcanic SO2 fluxes using satellite measurements of dispersed and large-scale plumes of SO2. We combine different approaches and investigate the temporal evolution of the total emissions of SO2 for a number of recent volcanic events in 2011: Nyamuragira (Congo), Nabro (Eritrea) and Puyehue (Chili). High spectral resolution satellite instruments operating both in the UV-visible (OMI/Aura and GOME-2/MetOp-A) and thermal Infrared (IASI/MetOp-A) spectral ranges are used in a synergistic way. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables to assess the consistency of the SO2 products from the different sensors used. Moreover, our estimates of SO2 fluxes are confronted to magma fluxes constraints obtained from independent thermal measurements. This work is performed in the frame of the European Volcano Observatory Space Services (EVOSS) EU FP7 project whose aim is to develop and demonstrate a portfolio of GMES Downstream Services, based on Earth Observation data products, to monitor volcanic activity and relevant hazards at a global scale. The region of interest of EVOSS (EU and Africa) is monitored for ground-deformations, thermal, SO2 and ash detection using state-of-the-art remote sensing techniques.

Theys, N.; Campion, R.; Clarisse, L.; Brenot, H.; van Gent, J.; Coheur, P.; Van Roozendael, M.; Tait, S.; Ferrucci, F.

2012-04-01

91

Benzosulfones as photochemically activated sulfur dioxide (SO2) donors.  

PubMed

Sulfur dioxide (SO2) is a gaseous environmental pollutant which is routinely used in industry as a preservative and antimicrobial. Recent data suggests that SO2 may have value as a therapeutic agent. However, due to its gaseous nature, localizing SO2 generation is challenging. Herein, various 1,3-dihydrobenzo[c]thiophene 2,2-dioxides (benzosulfones) were prepared as candidates for photochemically activated sulfur dioxide (SO2) generation. These compounds were found to be stable in buffer but were photolysed upon irradiation with UV light to generate SO2. Our data indicates that photolysis of benzosulfones depends on substituents, and that the presence of electron donating groups results in an enhanced yield of SO2. PMID:25563212

Malwal, Satish R; Chakrapani, Harinath

2015-02-10

92

Vertical distribution of volcanic SO2 retrieved from IASI.  

NASA Astrophysics Data System (ADS)

Sulphur dioxide (SO2) is an important atmospheric constituent that plays a rucial role in many atmospheric processes and its effect and lifetime are dependent on the SO2 injection altitude. In the troposphere SO2 production leads to the acidification of rainfall while in the stratosphere it oxidises to form a stratospheric H2SO4 haze that can affect climate for several years. We report applications of IASI high resolution infrared spectra to study volcanic emission of sulphur dioxide (SO2). IASI is a Fourier transform spectrometer that covers the spectral range 645 to 2760 cm-1 (3.62-15.5 um). The IASI field of view consists of four circles of 12 km inside a square of 50 x 50 km, and nominally it can achieve global coverage in 12 hours. From 2013 there were 2 IASI instruments on board both METOP A and B giving up to 4 overpasses a day. The SO2 retrieval algorithm uses measurements from 1000 to 1200 cm-1 and from 1300 to 1410 cm-1 (the 7.3 and 8.7 um SO2 bands) made by IASI on the MetOp satellite. The SO2 retrieval follows the method of Carboni et al. (2012) and retrieves SO2 amount and altitude together with a pixel by pixel comprehensive error budget analysis. It permits the quantification of SO2 amount and estimation of plume altitude, even for small eruptions in the lower troposphere (e.g. Etna lava fountains in 2011 and 2013). We present the SO2 amount described as a function of altitude, and the time evolution of SO2 burden for recent volcanic eruptions. Quantification of the total amount of SO2 over several days allows estimation of daily emission rates, and decay factors.

Carboni, Elisa; Grainger, Roy; Mather, Tamsin; Payle, David; Birch, Charlotte; Dudhia, Anu; Ventress, Lucy; Smith, Andy; Hayer, Caterine

2014-05-01

93

Effects of prolonged exposure of Oryzopsis hymenoides to SO 2  

Microsoft Academic Search

Oryzopsis hymenoides, a desert grass, was exposed to low concentrationsof SO2 ranging from 0.03 to 1.00 ppm for six week fumigation periods. Deleterious effects were noted only at atmospheric SO2 concentrations of 0.13 ppm and above. These effects included necrotic lesions and reduced net primary productivity. At concentrations below 0.13 ppm, the SO2 appeared to have a beneficial effect on

Roger W. Ferenbaugh

1978-01-01

94

Partial discharge early-warning through ultraviolet spectroscopic detection of SO2  

NASA Astrophysics Data System (ADS)

Surveillance of SF6 decomposition products is significant for detection of partial discharge (PD) in gas insulation switchgear (GIS). As a basis in on-site detection and diagnosis, PD early-warning aims to quickly find the abnormalities using a simple and cheap device. In this paper, SO2 is chosen as a feature product and detected through ultraviolet spectroscopy. The derivative method is employed for baseline correction and spectral enhancement. The standard gases of the main decomposition products are qualitatively and quantitatively detected. Then decomposition experiments with different defects are designed to further verify the feasibility. As a stable decomposition product under PD, SO2 is proved to be applicable for PD early-warning in the field. By selecting the appropriate wavelength range, namely 290-310 nm, ultraviolet derivative spectroscopy is sensitive enough to the trace SO2 in the decomposed gas and the interference of other products can be avoided. Fast Fourier transform could be used for feature extraction in qualitative detection. Concentrations of SO2 and other by-products increase with increasing discharge time and could be affected by the discharge energy and PD type. Ultraviolet detection based on SO2 is effective for PD early-warning but the threshold should still be carefully selected in practice.

Zhao, Yu; Wang, Xianpei; Dai, Dangdang; Dong, Zhengcheng; Huang, Yunguang

2014-03-01

95

BrO/SO2 molar ratios from scanning DOAS measurements in the NOVAC network  

NASA Astrophysics Data System (ADS)

The molar ratio of BrO to SO2 is, like other halogen/sulfur ratios, a possible precursor for dynamic changes in the shallow part of a volcanic system. While the predictive significance of the BrO/SO2 ratio has not been well constrained yet, it has the major advantage that this ratio can be readily measured using the remote-sensing technique differential optical absorption spectroscopy (DOAS) in the UV. While BrO/SO2 ratios have been measured during several short-term field campaigns, this article presents an algorithm that can be used to obtain long-term time series of BrO/SO2 ratios from the scanning DOAS instruments of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) or comparable networks. Parameters of the DOAS retrieval of both trace gases are given. The influence of co-adding spectra on the retrieval error and influences of radiative transfer will be investigated. Difficulties in the evaluation of spectroscopic data from monitoring instruments in volcanic environments and possible solutions are discussed. The new algorithm is demonstrated by evaluating data from the NOVAC scanning DOAS systems at Nevado del Ruiz, Colombia, encompassing almost 4 years of measurements between November 2009 and end of June 2013. This data set shows variations of the BrO/SO2 ratio several weeks prior to the eruption on 30 June 2012.

Lübcke, P.; Bobrowski, N.; Arellano, S.; Galle, B.; Garzón, G.; Vogel, L.; Platt, U.

2014-06-01

96

Regional climatic effects of atmospheric SO2 on Mars  

NASA Technical Reports Server (NTRS)

The conditions under which the valley networks on Mars may have formed remains controversial. The magnitude of an atmospheric greenhouse effect by an early massive CO2 atmosphere has recently been questioned by Kasting. Recent calculations indicate that if solar luminosity were less than about 86 percent of its current value, formation of CO2 clouds in the Martian atmosphere would depress the atmospheric lapse rate and reduce the magnitude of surface warming. In light of recent revisions of magma generation on Mars during each Martian epoch, and the suggestions by Wanke et al. that the role of liquid SO2 should be more carefully explored, we have recalculated the potential greenhouse warming by atmospheric SO2 on Mars, with an emphasis on more localized effects. In the vicinity of an active eruption, the concentration of atmospheric SO2 will be higher than if it is assumed that the erupted SO2 is instantaneously globally distributed. The local steady-state concentration of SO2 is a function of the rate at which it is released, its atmospheric lifetime, and the rate at which local winds act to disperse the SO2. We have made estimates of eruption rates, length of eruption, and dispersion rates of volcanically released SO2, for a variety of atmospheric conditions and atmospheric lifetimes of SO2 to explore the maximum regional climatic effect of SO2.

Postawko, S. E.; Fanale, F. P.

1992-01-01

97

The atmospheric abundance of SO2 on Io  

NASA Technical Reports Server (NTRS)

The IUE satellite has obtained near-UV spectra of Io with sufficient resolution to ascertain the east, or leading and west, or trailing hemispheres' dayside atmosphere SO2 abundance. The derived geometric albedos are compared with various model albedos that might result from proposed SO2 atmospheres, as well as from localized, sublimation- or volcanism-generated atmospheres. A homogeneous-layer alternative atmosphere is introduced whose upper limit on the average SO2 column density for both hemispheres implies that a collisionally thick SO2 atmosphere of intermediate density may have been present on Io's dayside during the present observations.

Ballester, Gilda E.; Strobel, Darrell F.; Moos, H. Warren; Feldman, Paul D.

1990-01-01

98

Effect of Plasma Treatment on Multi-Walled Carbon Nanotubes for the Detection of H2S and SO2  

PubMed Central

H2S and SO2 are important characteristic gases of partial discharge (PD) generated by latent insulated defects in gas insulated switchgear (GIS). The detection of H2S and SO2 is of great significance in the diagnosis and assessment of the operating status of GIS. In this paper, we perform experiments on the gas sensitivity of unmodified multi-walled carbon nanotubes (MWNTs) and those modified by atmospheric pressure dielectric barrier discharge (DBD) air plasma at different times (30, 60 and 120 s) for H2S and SO2, respectively. The results show that the sensitivity and response time of modified MWNTs to H2S are both improved, whereas the opposite effects are observed for SO2. The modified MWNTs have almost zero sensitivity to SO2. Thus, the MWNTs modified by atmospheric pressure DBD air plasma present good selectivity to H2S, and have great potential in H2S detection. PMID:23012548

Zhang, Xiaoxing; Yang, Bing; Wang, Xiaojing; Luo, Chenchen

2012-01-01

99

POLLUTION CONTROL PRACTICES: COST FOR CONTROL OF SO2 EMISSIONS  

EPA Science Inventory

The paper gives results of a study (part of a multiphased EPA study of the acid rain problem) the objectives of which were to (1) identify and characterize existing industrial sources of SO2 emissions, (2) identify the control techniques that can be used to reduce SO2 emissions f...

100

SO2 ABATEMENT FOR COAL-FIRED BOILERS IN JAPAN  

EPA Science Inventory

The report is a compilation of information on the current status of SO2 abatement technologies for coal-fired boilers in Japan, where strict ambient air quality standards for SO2 and NOx mandate the use of various air pollution control technologies. It focuses on flue gas desulfu...

101

JAPANESE ACTIVITIES IN SO2 AND NOX CONTROL  

EPA Science Inventory

The paper reviews Japanese activities in SO2 and NOx control. From 1970 to 1985, energy use in Japan increased by 25%, and annual coal consumption rose from virtually nothing to 20 million tons, yet emissions of SO2 declined by 75% and NOx by 40%. While increases in hydroelectric...

102

ACCURACY OF REMOTELY SENSED SO2 MASS EMISSION RATES  

EPA Science Inventory

Remote sensing data of single-stack power plant emissions and local wind speed have been analyzed to determined SO2 mass flux for comparison with EPA referenced methods. Four days of SO2 data were gathered from a moving platform by three upward-viewing remote sensors -- two ultra...

103

AN ADVANCED FLUE GAS MONITOR FOR SO2 - PHASE I  

EPA Science Inventory

The development of an instrument for continuously monitoring SO2 levels in flue gas is proposed. The SO2 will be detected by means of an electrochemical sensor cell, which operates in a three-electrode potentiostatic mode. The proposed innovation is develop-ment of an advan...

104

LOW NOX COMBUSTION SYSTEMS WITH SO2 CONTROL USING LIMESTONE  

EPA Science Inventory

The paper describes EPA work on low NOx combustion systems with SO2 control using limestone. Although SO2 control in low NOx systems for both stoker and pulverized-coal-fired furnaces is under investigation at EPA, most of the current work is with pulverized coal. EPA's Limestone...

105

STATUS OF DRY SO2 CONTROL SYSTEMS: FALL 1983  

EPA Science Inventory

The report, on the status of dry SO2 control for utility and industrial boilers in the U.S., reviews curent and recently completed research, development, and commercial activities. Dry SO2 control systems covered include: (1) spray dryers with a fabric filter or an electrostatic ...

106

Enhanced SO2 Concentrations Observed over Northern India: Role of Long-range Transport  

SciTech Connect

Volcanic emissions and coal burning are among the major sources of SO2 over the continental environment. In this study, we show episodes of long-range transport of volcanic SO2 from Africa to Northern India using satellite observations. Monthly averaged SO2 from OMI were of the order of 0.6-0.9 DU during November, 2008 over the Indo-Gangetic Plain (IGP), which far exceeded background values (<0.3 DU) retrieved from observations across different locations over North India during 2005-2010. The columnar SO2 loadings were much higher on November 6 over most of the IGP and even exceeded 6 DU, a factor of 10 higher than background levels at some places. These enhanced SO2 levels were, however, not reciprocated in satellite derived NO2 or CO columns, indicating transport from a non-anthropogenic source of SO2. Backward trajectory analysis revealed strong winds in the free troposphere, which originated from the Dalaffilla volcanic eruption over the Afar region of Ethiopia during November 4-6, 2008. Wind streams and stable atmospheric conditions were conducive to the long-range transport of volcanic plume into the IGP. As most of the local aerosols over IGP region are below 3 km, a well separated layer at 4-5 km is observed from CALIPSO, most likely as a result of this transport. Apart from known anthropogenic sources, the additional transport of volcanic SO2 over the IGP region would have implications to air quality and radiation balance over this region.

Mallik, C.; Lal, S.; Naja, M.; Chand, Duli; Venkataramani, S.; Joshi, H.; Pant, P.

2013-01-17

107

Studies on potential emission of hazardous gases due to uncontrolled open-air burning of waste vehicle tyres and their possible impacts on the environment  

NASA Astrophysics Data System (ADS)

Uncontrolled open-air burning of waste vehicle tyres causing environmental pollution has become a popular practice in Nepal despite official ban considering the environment and public health hazards. In this study, an experimental model was set up in a laboratory scale in an attempt to understand the potential emission of hazardous gases such as CO, SO 2 and NO 2 due to such activities in Kathmandu Valley and their possible impacts on the environment. For this purpose, four types of tyre were collected representing two from passenger car and two from motorbike category. The emission level of CO in the tyre smoke was measured with a CO gas detector tube while SO 2 and NO 2 were determined by UV-visible spectrophotometer. Among the three types of the gases analyzed, SO 2 was emitted in significantly high levels by all the representative tyre samples. The emission levels of CO, SO 2 and NO 2 ranged from 21to 49, 102to 820 and 3to 9 ?g g -1, respectively. Results revealed that the emission levels also varied with the tyre types and qualities. The potential emission of the hazardous gases per representative scrap tyre mass was also estimated. Results indicate that the gaseous pollutants due to the tyre fires could make a significant contribution for deterioration of the environmental condition of the Valley or elsewhere.

Shakya, Pawan R.; Shrestha, Pratima; Tamrakar, Chirika S.; Bhattarai, Pradeep K.

108

Distillation and detection of SO2 using a microfluidic chip.  

PubMed

A miniaturized distillation system is presented for separating sulfurous acid (H(2)SO(3)) into sulfur dioxide (SO(2)) and water (H(2)O). The major components of the proposed system include a microfluidic distillation chip, a power control module, and a carrier gas pressure control module. The microfluidic chip is patterned using a commercial CO(2) laser and comprises a serpentine channel, a heating zone, a buffer zone, a cooling zone, and a collection tank. In the proposed device, the H(2)SO(3) solution is injected into the microfluidic chip and is separated into SO(2) and H(2)O via an appropriate control of the distillation time and temperature. The gaseous SO(2) is then transported into the collection chamber by the carrier gas and is mixed with DI water. Finally, the SO(2) concentration is deduced from the absorbance measurements obtained using a spectrophotometer. The experimental results show that a correlation coefficient of R(2) = 0.9981 and a distillation efficiency as high as 94.6% are obtained for H(2)SO(3) solutions with SO(2) concentrations in the range of 100-500 ppm. The SO(2) concentrations of two commercial red wines are successfully detected using the developed device. Overall, the results presented in this study show that the proposed system provides a compact and reliable tool for SO(2) concentration measurement purposes. PMID:22159042

Ju, Wei-Jhong; Fu, Lung-Ming; Yang, Ruey-Jen; Lee, Chia-Lun

2012-02-01

109

SO2 passivating chemistry for silicon cryogenic deep etching  

NASA Astrophysics Data System (ADS)

Cryogenic deep etching of silicon is investigated using SO2 for passivating the sidewalls of the etched features. The passivating efficiency of SO2 in a SF6/SO2 inductively coupled plasma is assessed comparatively with the traditional SF6/O2 chemistry by means of mass spectrometry and optical emission spectroscopy diagnostics. Emphasis is placed on the evolution of the density of various neutral species (e.g. SiF4, F, O, SOxFy, SFx). These measurements allow us to determine the SO2/SF6 and O2/SF6 gas flow ratios above which a passivation layer forms and inhibits silicon etching. Furthermore, different reaction schemes are proposed to explain the variations in relative densities measured for the two plasma chemistries. In SF6/SO2 plasmas, surface reactions involving SOF and SO2 species with F radicals are favoured, providing a greater number of SOF2 and SO2F2 molecules in the gas phase. In SF6/O2 plasmas, a higher rate of O radicals available for reacting with SFx species can account for the greater concentration in SOF4 molecules. However, these trends are significant for high passivating gas concentrations only. This is consistent with the similar etch results obtained for both chemistries when etching silicon at cryogenic temperatures with a low percentage of passivating gas.

Duluard, C. Y.; Dussart, R.; Tillocher, T.; Pichon, L. E.; Lefaucheux, P.; Puech, M.; Ranson, P.

2008-11-01

110

Observations of SO2 and HCS(+) in cold molecular clouds  

NASA Technical Reports Server (NTRS)

The first instance of SO2 emission from a dark dust cloud (L183), and the first astronomical detections of the J = 1-0 rotational transition of the HCS(+) ion and the J = 16-15 transition of HC5N, both towards the cold cloud TMC-1, are reported. The HCS(+)/CS abundance ratio in TMC-1 is greater than about 0.1. Unlike HCS(+) and the cyanopolyynes, SO2 appears to be more abundant in L183 than in TMC-1. SO2 was also detected in the Orion ambient molecular cloud and in the Rho Oph cloud.

Irvine, W. M.; Good, J. C.; Schloerb, F. P.

1983-01-01

111

The effect of SO2 on mineral carbonation in batch tests  

SciTech Connect

CO2 sequestration is a key element of future emission-free fossil-fueled power plants. Other constituents of flue gas must also be captured and rendered innocuous. Contemporary power plants remove SOx from exit gases, but next-generation plants may simultaneously treat CO2, SOx, and other pollutants. Pioneering tests at the U.S. Department of Energy's Albany Research Center investigated the combined treatment of CO2 and SO2 in a mineral-carbonation process. SO2 was removed from the gas stream, and as a small fraction of the total volume of mineralizing gas, it did not inhibit the carbonation reaction. The results indicate that this approach to CO2 sequestration could be used to treat multiple pollutants.

Summers, Cathy A.; Dahlin, David C.; Ochs, Thomas L.

2004-01-01

112

Conformal invariance: From Weyl to SO(2,d)  

NASA Astrophysics Data System (ADS)

The present work deals with two different but subtilely related kinds of conformal mappings: Weyl rescaling in d > 2 dimensional spaces and SO(2,d) transformations. We express how the difference between the two can be compensated by diffeomorphic transformations. This is well known in the framework of string theory but in the particular case of d = 2 spaces. Indeed, the Polyakov formalism describes world sheets in terms of two-dimensional conformal field theory (CFT). On the other hand, Zumino had shown that a classical four-dimensional Weyl-invariant field theory restricted to live in Minkowski space leads to an SO(2,4)-invariant field theory. We extend Zumino's result to relate Weyl and SO(2,d) symmetries in arbitrary conformally flat spaces (CFS). This allows us to assert that a classical SO(2,d)-invariant field does not distinguish, at least locally, between two different d-dimensional CFSs.

Faci, S.

2013-02-01

113

Supply of SO2 for the atmosphere of Io  

NASA Astrophysics Data System (ADS)

The authors point out that in addition to a vapor pressure equilibrium source of SO2 in an atmosphere of Io, recent laboratory sputtering results, combined with Voyager-measured particle fluxes, indicate that SO2 could also result from charged particle erosion of frost deposits on the satellite's surface. On the nightside, and for dayside frost patches where the temperature may be ?100K, such erosion will be a dominant mechanism.

Lanzerotti, L. J.; Brown, W. L.

1983-02-01

114

Orbifold Family Unification in SO(2N) Gauge Theory  

E-print Network

We study the possibility of family unification on the basis of SO(2N) gauge theory on the five-dimensional space-time, $M^4\\times S^1/Z_2$. Several SO(10), $SU(4) \\times SU(2)_L \\times SU(2)_R$ or SU(5) multiplets come from a single bulk multiplet of SO(2N) after the orbifold breaking. Other multiplets including brane fields are necessary to compose three families of quarks and leptons.

Yoshiharu Kawamura; Takashi Miura

2009-12-04

115

Laser-induced fluorescence instrument for measuring atmospheric SO 2  

NASA Astrophysics Data System (ADS)

We report on the development of a high-sensitive detection system for measuring atmospheric SO 2 using a laser-induced fluorescence (LIF) technique at around 220 nm. Second harmonics of a tunable broad-band optical parametric oscillator (OPO) pumped by the third harmonic of a Nd:YAG laser is used as a fluorescence excitation source. The laser wavelength is alternatively tuned to the peak and the bottom wavelengths in the photoabsorption spectrum of SO 2 at 220.6 and 220.2 nm, respectively, and the difference signal at the two wavelengths is used to extract the SO 2 concentration. This procedure can give a good selectivity for SO 2 and avoid interferences of fluorescent or particulate species other than SO 2 in the sample air. The SO 2 instrument developed has a sensitivity of 5 pptv in 60 s and S/N=2. The practical performance of the detection system is tested in the suburban area. The inter-comparisons between the LIF instrument and a commercial instrument using Xe flash lamp excitation for the fluorescence detection have been performed. The correlation between two instruments is measured up to 70 ppbv. A good linear relationship between the LIF measurements and commercial instrument measurements is obtained.

Matsumi, Yutaka; Shigemori, Hiroyuki; Takahashi, Kenshi

116

Roles of SO2 oxidation in new particle formation events.  

PubMed

The oxidation of SO2 is commonly regarded as a major driver for new particle formation (NPF) in the atmosphere. In this study, we explored the connection between measured mixing ratio of SO2 and observed long-term (duration>3hr) and short-term (duration <1.5hr) NPF events at a semi-urban site in Toronto. Apparent NPF rates (J30) showed a moderate correlation with the concentration of sulfuric acid ([H2SO4]) calculated from the measured mixing ratio of SO2 in long-term NPF events and some short-term NPF events (Category I) (R(2)=0.66). The exponent in the fitting line of J30~[H2SO4](n) in these events was 1.6. It was also found that SO2 mixing ratios varied a lot during long-term NPF events, leading to a significant variation of new particle counts. In the SO2-unexplained short-term NPF events (Category II), analysis showed that new particles were formed aloft and then mixed down to the ground level. Further calculation results showed that sulfuric acid oxidized from SO2 probably made a negligible contribution to the growth of >10nm new particles. PMID:25872713

Meng, He; Zhu, Yujiao; Evans, Greg J; Jeong, Cheol-Heon; Yao, Xiaohong

2015-04-01

117

Co-Sequestration Geochemical Modeling: Simple Brine Solution + CO2-O2-SO2  

NASA Astrophysics Data System (ADS)

Class H well cement (LaFarge) was exposed to supercritical CO2 to evaluate the impact of brine chemistry on the well cement. Simulated experimental downhole conditions include a pressure of 28.6 MPa and a temperature of 50oC. Brine composition was formulated from the NETL NATCARB database, resulting in a simple solution of 1 M (NaCl, MgCl2, CaCl2). It was determined that the brine chemistry plays a vital role in determining the degree and type of alteration of cement in carbon sequestration conditions. The implications of co-sequestration (CO2/O2/SO2 mixtures) from of oxy-fueled combustion, coal gasification and sour gas have been considered. Geochemical modeling was conducted to understand the interaction between formation brine, cement and co-contaminant gases, using a gas composition of 95.5% CO2, 4% O2, and 1.5% SO2. The modeling results are significant in determining the validity of co-sequestering coal flue gas containing SOx gases or sour hydrocarbon gas which could potentially produce pyrite or other sulfur-bearing species in the cement via mineralization trapping. Thermodynamic components of aqueous species, gases, and minerals were used to calculate the pH and mineral saturation indices using CHIM-XPT. The computed pH of the solution is 4.34. The total sulfate molality within the brine is 0.0095 M. In experimental conditions of 600 mL of brine, 0.0057 moles of sulfate will be converted into 5.7 mL of sulfuric acid. The modeling shows that an excess of 31% O2 forms, indicating that H2S from SO2 disporportionation is oxidized to sulfate, thus no gaseous H2S will form. Remaining SO2 in the experimental headspace has a predicted mole fraction is 10-46. Additional SO2 gas added to the system produces the reaction to precipitate gypsum. Additional gas reactions precipitate gypsum, anhydrite, calcite, and dolomite.

Verba, C.; Kutchko, B. G.; Reed, M. H.

2012-12-01

118

Satellite SO2 retrievals from ash rich volcanic plumes: Comparison between different correction procedures  

NASA Astrophysics Data System (ADS)

Observations of volcanic degassing yield insights into the magmatic processes which control volcanic activity during both quiescent and eruptive phases. SO2 is an important volcanic gas because of its effects on the environment (e.g. acid rain, effects on plants and public health) and also because once it has reached high altitudes it can be transported over long distances, has a great residence time and can be oxidized to form sulphates. The sulphates are capable of reflecting solar radiation and causing surface cooling. For these reasons there is great interest in improving the quality and frequency of volcanic SO2 retrievals. Satellite observations have been used for a long time to monitor globally distributed volcanic activity because they offer a practical and safe source of valuable data. While no satellite sensor has been developed explicitly for volcanic observations, continuous technological improvement has achieved spatial resolutions and acquisition frequencies that allow increasingly detailed volcanological studies at local scales. Monitoring of volcanic SO2 is one of the key facilities offered by satellite remote sensing techniques both in the UV and in the TIR spectral range. During volcanic eruptions ash and gases can be emitted simultaneously. The plume ash particles (from 1 to 10 micron) tend to reduce the top of atmosphere radiance in the entire Thermal InfraRed spectral range (7-14 micron), including the channels used for the SO2 retrieval. The net effect is a significant SO2 column abundance overestimation. In this work three different ash correction procedures for SO2 volcanic plume retrieval are compared. These procedures, applied to MODIS and ASTER TIR measurements, has been used to retrieve the SO2 emission from the 2010 Eyjafjallajokull (Iceland) and the 2011 Mt. Etna (Italy) eruptions. The first procedure (P1), based on Corradini et al. 2009, needs the simultaneous presence of the 8.7 micron SO2 absorption bands, as well as the split window bands centered around 11 and 12 micron used for ash retrieval. This implies the possibility of a simultaneous retrieval of both volcanic SO2 and ash in the same data set. The procedure is based on computing the plume atmospheric terms, taking into account the ash content of the different pixels, by using MODTRAN 4 radiative transfer model. The second procedure (P2), based on Campion et al. 2010, consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations. The selected band ratios depend much less on atmospheric humidity, sulfate aerosols, surface altitude and emissivity than the raw radiances. The third (P3) is a novel procedure which determines the radiance at the sensor if no plume was in the scene and then the plume transmittance at each band. A relationship, of the ash transmittance at 8.7 versus 11 micron transmittance, is used to retrieve the SO2 abundance. The P1 procedure has been considered as a reference. Its main drawback is the time required to compute the simulated atmospheric terms Look-Up Tables. The P2 procedure, valid for ASTER images, gives a very good spatial resolution but, because of that, the plume is generally not completely observed. The P3 procedure is very fast and can be used for a volcanic early warning, but seems too sensitive to the plume temperature. Even if the P1 procedure tends to overestimate the SO2 amounts with respect to the P2 and P3 procedures, the results show a good agreement in both the the SO2 flux trends and total mass for all the different eruptive events considered.

Corradini, S.; Pugnaghi, S.; Campion, R.; Arvani, B.; Guerrieri, L.; Merucci, L.

2012-04-01

119

Special Polymer/Carbon Composite Films for Detecting SO2  

NASA Technical Reports Server (NTRS)

A family of polymer/carbon films has been developed for use as sensory films in electronic noses for detecting SO2 gas at concentrations as low as 1 part per million (ppm). Most previously reported SO2 sensors cannot detect SO2 at concentrations below tens of ppm; only a few can detect SO2 at 1 ppm. Most of the sensory materials used in those sensors (especially inorganic ones that include solid oxide electrolytes, metal oxides, and cadmium sulfide) must be used under relatively harsh conditions that include operation and regeneration at temperatures greater than 100 C. In contrast, the present films can be used to detect 1 ppm of SO2 at typical opening temperatures between 28 and 32 C and can be regenerated at temperatures between 36 and 40 C. The basic concept of making sensing films from polymer/carbon composites is not new. The novelty of the present family of polymer/carbon composites lies in formulating the polymer components of these composites specifically to optimize their properties for detecting SO2. First-principles quantum-mechanical calculations of the energies of binding of SO2 molecules to various polymer functionalities are used as a guide for selecting polymers and understanding the role of polymer functionalities in sensing. The polymer used in the polymer-carbon composite is a copolymer of styrene derivative units with vinyl pyridine or substituted vinyl pyridine derivative units. To make a substituted vinyl pyridine for use in synthesizing such a polymer, poly(2-vinyl pyridine) that has been dissolved in methanol is reacted with 3-chloropropylamine that has been dissolved in a solution of methanol. The methanol is then removed to obtain the copolymer. Later, the copolymer can be dissolved in an appropriate solvent with a suspension of carbon black to obtain a mixture that can be cast and then dried to obtain a sensory film.

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

2008-01-01

120

Mineral Sequestration of CO2 mixed with H2S and SO2 in Sandstone-Shale Formation  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) injection into deep geologic formations can potentially reduce atmospheric emissions of greenhouse gases. Sequestering less-pure CO2 waste streams (containing of H2S and/or SO2) is less expensive or requires less energy than separating CO2 from flue gas or a coal gasification process. The long-term interaction of these injected acid gases with shale-confining layers of sandstone formations has not been well investigated. We therefore have developed a conceptual model of injection of CO2 with H2S and/or SO2 into a sandstone-shale sequence, using hydrogeologic properties and mineral compositions commonly encountered in Gulf Coast sediments. We have performed numerical simulations using a 1-D radial well region considering sandstone alone and a 2-D model using a sandstone-shale sequence under acid-gas injection conditions. Results indicate that shale plays a limited role in mineral alteration and sequestration of gases within a sandstone horizon for a short time period (10,000 years in present simulations). Unlike H2S, the co-injection of SO2 results in different pH distribution, mineral alteration patterns, and CO2 mineral sequestration. Simulations generate a zonal distribution of mineral alteration and formation of CO2 and SO2 trapping minerals that depends the pH distribution. Co-injection of SO2 results in a larger and stronger acidic zone close to the well. Precipitation of CO2 trapping minerals occurs in the higher pH ranges beyond the acidic zones. In contrast, SO2 trapping minerals are stable at low pH ranges (below 5) in the front of the acidic zone. Corrosion and well abandonment caused by co-injection of SO2 is a very significant issue. Significant CO2 is sequestered in ankerite and dawsonite, and some in siderite. CO2 mineral-trapping capability can reach 76 kg per cubic meter of medium. Most of SO2 is trapped by alunite precipitation, while some of the SO2 is trapped by anhydrite and pyrite precipitation. Addition of the acid gases and induced mineral alteration result in changes in porosity. The limited information currently available on the mineralogy of natural high-pressure acid-gas reservoirs is generally consistent with our simulations.

Xu, T.; Pruess, K.; Apps, J. A.; Yamamoto, H.

2004-12-01

121

Light-Induced SO2 Photochemistry at the Mineral Dust Surface  

NASA Astrophysics Data System (ADS)

The uptake of SO2 by mineral dust is believed to proceed first by formation of surface-bound sulfite, which can subsequently be oxidized to sulfate not only by co-sorbed O3 and NO2 but also by photooxidants such as Fe and Ti present within the dust itself. In the first phase of this study, we investigated the effect of light upon SO2 uptake by Fe2O3, TiO2, illite, feldspar, and mineral dust samples obtained from Niger, Tunisia, and China. We determined the initial uptake coefficient of SO2 at the surface of dust samples under both light and dark conditions using a photochemical Knudsen cell, and then measured the relative quantities of sulfite and sulfate formed at the surface of these films using ion chromatography. In the second phase of this study, which was performed in the CESAM atmospheric chamber, we explored the possibility that light-induced production of surface-sorbed sulfate might result in enhanced dust hygroscopicity by measuring changes in dust particle size distribution as a function of exposure to SO2 and light under a range of relative humidity conditions.

Styler, S. A.; Doussin, J.; Formenti, P.; Donaldson, D.

2013-12-01

122

Contribution of SO2 to antioxidant potential of white wine.  

PubMed

The reactivity of SO2 with the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and in Folin Ciocalteu (FC) assays was analysed under different experimental conditions. There was significantly higher reactivity between SO2 and DPPH in buffered methanol than in methanol alone. When DPPH and FC assays were performed in a mixture of caftaric acid and SO2, there were synergistic effects that were more pronounced with the FC assay. Phenolics are an important parameter of wine quality, and their accurate characterisation in wine is essential. Analysis of white wines with DPPH and FC assays overestimates the contribution of phenolics to the antioxidant potential (AOP). SO2 contributes (from 20% to 45%) to the AOP of the white wines analysed. As SO2 reactivity depends highly on buffer composition, pH, time of incubation and other compounds, e.g. phenolics and aldehydes, different experimental protocols can produce large variations in AOPs, and therefore control of experimental conditions is extremely important. PMID:25529664

Abramovi?, Helena; Košmerl, Tatjana; Poklar Ulrih, Nataša; Cigi?, Blaž

2015-05-01

123

Disk-resolved Millimeter Observations Of Io's SO2 Atmosphere  

NASA Astrophysics Data System (ADS)

We present spectral maps of Io's SO2 atmosphere obtained with the Plateau de Bure Interferometer (PdBI) in winter 2005, on the leading and trailing hemispheres of Io. The PdBI was in its extended configuration, providing a 0.5x1.5 arcsec synthetized beam at 1.3 mm, and allowing to resolve Io in its longitudinal direction. Continuum analysis in the UV plane indicates a mean continuum brightness temperature of 100K, rather constant with longitude and local time, suggesting sub-surface sounding. The SO2 216.643 GHz line was detected on both hemispheres, with disk-integrated line contrasts of 55 and 25 K. On the leading side, the data indicate a 400 m.s-1 limb to limb spectral shift difference. On both sides, the SO2 emission is spatially narrower than the continuum emission, indicating a localized atmosphere. Moreover, the emission appears to be displaced with respect to continuum emission, to the East on the leading side, to the North on the trailing side. We tried to model the observations by assuming emission from an hydrostatic atmosphere in LTE conditions, using SO2 distributions determined from HST UV disk-resolved data (Feaga, 2005) and IR disk-integrated observations (Spencer et al, 2005). The line contrasts imply atmospheric temperatures around 150-200 K. On the leading side, the line shifts and widths (about 700 m.s-1) can be reproduced by a zonal superrotation with 300m.s-1 speed. However, the modelled SO2 line emission map appears spatially broader than the observed emission. On the trailing side, the Northern displacement cannot be reproduced by the assumed SO2 distributions. We are currently testing the volcanic plume models of Zhang et al. (2003) by implementing a radiative transfer model including local variations of number density, temperature, and velocity. The ultimate goal is to distiguish between SO2 sublimation and volcanic outgassing as the dominant source for Io's SO2 atmosphere.

Moullet, Arielle; Lellouch, E.; Moreno, R.; Gurwell, M. A.

2006-09-01

124

40 CFR 53.32 - Test procedures for methods for SO2, CO, O3, and NO2.  

Code of Federal Regulations, 2011 CFR

...period divided by the time period. Integration of the instantaneous concentration...reference methods. Details of the means of integration and any corrections shall be submitted...period divided by the time period. This integration may be performed by any...

2011-07-01

125

40 CFR 53.32 - Test procedures for methods for SO2, CO, O3, and NO2.  

Code of Federal Regulations, 2010 CFR

...period divided by the time period. Integration of the instantaneous concentration...reference methods. Details of the means of integration and any corrections shall be submitted...period divided by the time period. This integration may be performed by any...

2010-07-01

126

NO2 and SO2dispersion modeling and relative roles of emission sources over Map Ta Phut industrial area, Thailand  

Microsoft Academic Search

Map Ta Phut industrial area (MA) is the largest industrial complex in Thailand. There has been concern about many air pollutants over this area. Air quality management for the area is known to be difficult, due to lack of understanding of how emissions from different sources or sectors (e.g., industrial, power plant, transportation, and residential) contribute to air quality degradation

Chatinai Chusai; Kasemsan Manomaiphiboon; Phirun Saiyasitpanich; Sarawut Thepanondh

2012-01-01

127

NO2 and SO2 Dispersion Modeling and Relative Roles of Emission Sources over Map Ta Phut Industrial Area, Thailand  

Microsoft Academic Search

Map Ta Phut Industrial Area (MA) is the largest industrial complex in Thailand. There has been a concern for many air pollutants over this area. Air quality management for the area is known to be difficult due to lack of understanding of how emissions from different sources or sectors (e.g., industrial, power plant transportation, and residential) contribute to air quality

Chatinai Chusai; Kasemsan Manomaiphiboon; Phirun Saiyasitpanich; Sarawut Thepanondh

2012-01-01

128

40 CFR 53.32 - Test procedures for methods for SO2, CO, O3, and NO2.  

Code of Federal Regulations, 2014 CFR

...between 105 and 125 volts. All methods shall be calibrated as specified...sampler(s), and reference method shall be in strict...intended only to facilitate visual evaluation of data submitted. (3...2) of this section, each method shall be operated in the...

2014-07-01

129

40 CFR 53.32 - Test procedures for methods for SO2, CO, O3, and NO2.  

Code of Federal Regulations, 2013 CFR

...between 105 and 125 volts. All methods shall be calibrated as specified...sampler(s), and reference method shall be in strict...intended only to facilitate visual evaluation of data submitted. (3...2) of this section, each method shall be operated in the...

2013-07-01

130

40 CFR 53.32 - Test procedures for methods for SO2, CO, O3, and NO2.  

Code of Federal Regulations, 2012 CFR

...between 105 and 125 volts. All methods shall be calibrated as specified...sampler(s), and reference method shall be in strict...intended only to facilitate visual evaluation of data submitted. (3...2) of this section, each method shall be operated in the...

2012-07-01

131

BOILER SIMULATOR STUDIES ON SORBENT UTILIZATION FOR SO2 CONTROL  

EPA Science Inventory

The report gives results of a program to provide process design information for sorbent utilization as applied to EPA's LIMB process. Specifically, the program was designed to investigate the role of boiler thermal history, sorbent injection location, Ca/S molar ratio, and SO2 pa...

132

On parameters for the group SO(2n) James Arthur  

E-print Network

On parameters for the group SO(2n) James Arthur In memory of Ilya Piatetski-Shapiro. 1. Background Discovery Grant A3483. 1 #12;2 JAMES ARTHUR We write (G) as in [A3] for the set of equivalence classes of L

Arthur, James G.

133

COMBUSTION ENGINEERING'S FURNACE SORBENT INJECTION PROGRAMS FOR SO2 CONTROL  

EPA Science Inventory

The paper discusses three Combustion Engineering programs relating to the furnace sorbent injection process, a low-cost method for controlling sulfur dioxide (SO2) emissions from tangentially fired, coal burning boilers. The programs are: (1) pilot-scale investigations in the lab...

134

SO2 SCRUBBING TECHNOLOGIES: A REVIEW: JOURNAL ARTICLE  

EPA Science Inventory

NRMRL-RTP-P-585 Srivastava*, R.K., Jozewicz, W., and Singer, C. SO2 Scrubbing Technologies: a Review. Environmental Progress 20 (4):219-227 (2001). EPA/600/J-02/022, Available: Environmental Progress (journal), http://www.aiche.org/publications/tocs/issuedtl.asp, [NET]. 03...

135

BENCH SCALE STUDIES OF LIMESTONE INJECTION FOR SO2 CONTROL  

EPA Science Inventory

The report gives results of experiments in a boiler simulator furnace, indicating that the parameters of major importance to SO2 capture are thermal environment, calcium/sulfur ratio, and sorbent composition. Thermal environment (local temperature) had a strong effect on the util...

136

Investigating Statospheric Loss Rates of Volcanic SO2  

Microsoft Academic Search

Explosive volcanism is the predominant pathway for sulfur species to enter the stratosphere. The most important species is sulfur dioxide (SO2) which subsequently converts to sulfuric acid (H2SO4) aerosol particles. The aerosol particles have relatively long lifetimes in the dry, stable stratosphere and have potential consequences for both climate and atmospheric chemistry. The aerosol particles can reflect incoming solar radiation,

J. M. Shannon; G. J. Bluth; A. J. Prata

2002-01-01

137

Detoxification of Dissolved SO2 (Bisulfite) by Terricolous Mosses  

PubMed Central

• Background and Aims The widespread calcifuge moss Pleurozium schreberi is moderately tolerant of SO2, whereas Rhytidiadelphus triquetrus is limited to calcareous soils in regions of the UK that were strongly affected by SO2 pollution in the 20th century. The proposition that tolerance of SO2 by these terricolous mosses depends on metabolic detoxification of dissolved bisulfite was investigated. • Methods The capacities of the two mosses to accelerate loss of bisulfite from aqueous solutions of NaHSO3 were studied using DTNB [5, 5-dithio-(2-nitrobenzoic acid)] to assay bisulfite, and HPLC to assay sulfate in the incubation solutions. Incubations were performed for different durations, in the presence and absence of light, at a range of solution pH values, in the presence of metabolic inhibitors and with altered moss apoplastic Ca2+ and Fe3+ levels. • Key Results Bisulfite disappearance was markedly stimulated in the light and twice as great for R. triquetrus as for P. schreberi. DCMU, an inhibitor of photosynthetic electron chain transport, significantly reduced bisufite loss. • Conclusions Bisulfite (SO2) tolerance in these terricolous mosses involves extracellular oxidation using metabolic (photo-oxidative) energy, passive oxidation by adsorbed Fe3+ (only available to the calcifuge) and probably also internal metabolic detoxification. PMID:16319108

BHARALI, BHAGAWAN; BATES, JEFFREY W.

2006-01-01

138

CHARACTERIZATION OF ADVANCED SORBENTS FOR DRY SO2 CONTROL  

EPA Science Inventory

The paper discusses the development of new flyash/lime sorbents for removing SO2 from coal-fired flue gas. Flyash/lime weight ratios of 1:1 to 10:1 and several additives to these sorbents for promoting their reactivity were evaluated in a bench-scale reactor simulating conditions...

139

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 4. SESSION 7  

EPA Science Inventory

The proceedings document the 1991 SO2 Control Symposium, held December 3-6, 1991, in Washington, DC, and jointly sponsored by the Electric Power Research Institute (EPRI), the U. S. Environmental Protection Agency (EPA), and the U.S. Department of Energy (DOE). he symposium focus...

140

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 5. SESSION 8  

EPA Science Inventory

The proceedings document the 1991 SO2 Control Symposium, held December 3-6, 1991, in Washington, DC, and jointly sponsored by the Electric Power Research Institute (EPRI), the U. S. Environmental Protection Agency (EPA), and the U.S. Department of Energy (DOE). he symposium focus...

141

EVALUATION OF SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGY  

EPA Science Inventory

The report gives results of work concentrating on characterizing three process operational parameters of a technology that combines sorbent injection and selective non-catalytic reduction for simultaneous sulfur dioxide/nitrogen oxide (SO2/NOx) removal from coal-fired industrial ...

142

Variability of the SO2 Atmosphere of Io  

NASA Astrophysics Data System (ADS)

Io is the most volcanically active body in the solar system and plays an important role in supplying material to the entire Jovian system. A combination of volcanism and sublimation has maintained an atmosphere on Io primarily consisting of SO2. Analysis of the reflected solar Lyman-? intensities from the disk of Io has proved to be an effective method of mapping the atmospheric SO2 distribution. It has been shown using HST Space Telescope Imaging Spectrograph (STIS) data that an equatorial SO2 atmosphere, N ˜ 1-4 x1016 cm-2, decreasing to below 1015 cm-2 at the poles exists at Io (Feldman et al. 2000, GRL 27, 1787, Strobel & Wolven 2001, Ap & SS 277, 271). Although this general trend is seen in all HST/STIS G140L data of Io acquired from 1997-2001, there are large variations in the Lyman-? intensities at latitudes larger than +/-20° between dates as well as north/south asymmetries observed in the same exposure. The variability could be due to either temporal changes in the SO2 atmosphere or spatial differences at Io, in particular the location of surface features and volcanoes. We analyze the Lyman-? signature in a sub-set of the HST/STIS data, in which there are both temporal and longitudinal commonalities, to distinguish between temporal and spatial variations, to quantitatively describe the variations at higher latitudes, and to attempt a correlation between bright surface frosts or volcanic centers and significant spatial variations.

Feaga, L. M.; McGrath, M. A.; Feldman, P. D.; Strobel, D. F.

2003-05-01

143

INTRASPECIFIC VARIABILITY IN METABOLIC RESPONSES TO SO2  

EPA Science Inventory

Variation in metabolic responses to sulfur dioxide is widespread within many plant species. Plant responses are a consequence of a series of biochemical and physiological events beginning with SO2 flux into plant and progressing through perturbation, and homeostasis, and ending w...

144

SO2 AND NOX CONTROL TECHNOLOGY RESEARCH, DEVELOPMENT, AND DEMONSTRATION  

EPA Science Inventory

The paper describes EPA work in several areas relating to reducing SO2 and NOx emissions from coal-fired utility boilers, and provides an overview of objectives, approach, current status, and plans for each. In addition, it describes plans for a small-scale selective catalytic re...

145

Historical analysis of SO2 pollution control policies in China.  

PubMed

Coal is not only an important energy source in China but also a major source of air pollution. Because of this, China's national sulfur dioxide (SO(2)) emissions have been the highest in the world for many years, and since the 1990s, the territory of China's south and southwest has become the third largest acid-rain-prone region in the world. In order to control SO(2) emissions, the Chinese government has formulated and promulgated a series of policies and regulations, but it faces great difficulties in putting them into practice. In this retrospective look at the history of SO(2) control in China, we found that Chinese SO(2) control policies have become increasingly strict and rigid. We also found that the environmental policies and regulations are more effective when central officials consistently give environmental protection top priority. Achieving China's environmental goals, however, has been made difficult by China's economic growth. Part of this is due to the practice of environmental protection appearing in the form of an ideological "campaign" or "storm" that lacks effective economic measures. More recently, better enforcement of environmental laws and regulations has been achieved by adding environmental quality to the performance assessment metrics for leaders at all levels. To continue making advances, China needs to reinforce the economic and environmental assessments for pollution control projects and work harder to integrate economic measures into environmental protection. Nonetheless, China has a long way to go before economic growth and environmental protection are balanced. PMID:19159968

Gao, Cailing; Yin, Huaqiang; Ai, Nanshan; Huang, Zhengwen

2009-03-01

146

STATUS OF DRY SO2 CONTROL SYSTEMS: FALL 1982  

EPA Science Inventory

The report, updating the status of dry SO2 control systems for coal-fired utility and industrial boilers in the U.S. through the Fall of 1982, is based on current and recent research, research and development, and commercial activities. Systems addressed include: (1) spray dryer/...

147

DEVELOPMENT OF AN SO2 MONITOR FOR MOBILE SOURCES  

EPA Science Inventory

An instrument has been designed and built to monitor the concentration of SO2 in the exhaust of mobile sources. A grating assembly disperses the ultraviolet energy from a deuterium-arc source and passes five narrow spectral intervals. Three of the intervals (set A) coincide with ...

148

China's rapid deployment of SO2 scrubbers Robert H. Williamsb  

E-print Network

China's rapid deployment of SO2 scrubbers Yuan Xu,*a Robert H. Williamsb and Robert H. Socolowcth March 2009 DOI: 10.1039/b901357c Details are gradually emerging regarding China's extraordinary also describe novel policies enacted by China in 2007 to increase the likelihood that installed

149

40 CFR 97.288 - CAIR SO2 allowance allocations to CAIR SO2 opt-in units.  

Code of Federal Regulations, 2010 CFR

...under § 97.284(c); or (ii) The CAIR SO2 opt-in unit's heat input, as determined in accordance with subpart HHH of this part, for the immediately prior control period, except when the allocation is being calculated for the control...

2010-07-01

150

40 CFR 96.288 - CAIR SO2 allowance allocations to CAIR SO2 opt-in units.  

Code of Federal Regulations, 2010 CFR

...under § 96.284(c); or (ii) The CAIR SO2 opt-in unit's heat input, as determined in accordance with subpart HHH of this part, for the immediately prior control period, except when the allocation is being calculated for the control...

2010-07-01

151

IASI total mass of SO2 Amount of SO2 retrieved from IASI data. The values are the measured  

E-print Network

the results for recent volcanic eruptions (Monserrat, Eyjafjallajokull, Grimsvotn, Puyehue, Nabro, Etna quiescent degassing from some volcano. Wavenumber [cm-1] BT[k] SO2 absorption bands n1 n3 ash - IASI indicates the location of active volcano. Minimum error estimate surface contrast = skin temperature

Oxford, University of

152

Structural characterization of 1,1,3,3-tetramethylguanidinium chloride ionic liquid by reversible SO2 gas absorption.  

PubMed

A unique new ionic liquid-gas adduct solid state compound formed between 1,1,3,3-tetramethylguanidinium chloride ([tmgH]Cl) and sulfur dioxide has been characterized by X-ray diffraction and Raman spectroscopy. The structure contains SO2 molecules of near normal structure kept at their positions by Cl-S interactions. The crystals belong in the orthorhombic system, space group Pbcn, with unit cell dimensions of a = 15.6908(10) Å, b = 9.3865(6) Å, and c = 14.1494(9) Å, angles ? = ? = ? = 90°, and Z = 8 at 120 K. The [tmgH]Cl has a very high absorption capacity of nearly 3 mol of SO2 per mol of [tmgH]Cl at 1 bar of SO2 and at room temperature. However, part of the absorbed SO2 was liberated during the crystallization, probably because the crystal only accommodates one molecule of SO2 per [tmgH]Cl. The nature of the high absorption capacity of [tmgH]Cl as well as of the homologous compounds with bromide and iodide are discussed. Some of these salts may prove useful as reversible absorbents of SO2 in industrial flue gases. PMID:24088034

Berg, Rolf W; Harris, Pernille; Riisager, Anders; Fehrmann, Rasmus

2013-11-01

153

Sulfur dioxide in geothermal waters and gases  

Microsoft Academic Search

Methods were developed for stabilizing SO 2 in water and gas samples. The pararosaniline colorimetric method, and a gas Chromatographic method using a flame photometric detector specific for sulfur gases were used to assay SO 2 . Assays were also performed for sulfide, elemental sulfur and sulfate. A large number of acidic, neutral, and alkaline springs in Yellowstone National Park

Stephen Zinder; Thomas D. Brock

1977-01-01

154

On classification of geometries with SO(2,2) symmetry  

NASA Astrophysics Data System (ADS)

Motivated by the Extremal Vanishing Horizon (EVH) black holes, their near horizon geometry and the EVH/CFT proposal [1], we construct and classify solutions with (local) SO(2,2) symmetry to four and five dimensional Einstein-Maxwell-Dilaton (EMD) theory with positive, zero or negative cosmological constant ?, the EMD-? theory, and also U(1)4 gauged supergravity in four dimensions and U(1)3 gauged supergravity in five dimensions. In four dimensions the geometries are warped product of AdS3 with an interval or a circle. In five dimensions the geometries are of the form of warped product of AdS3 and a 2d surface ?2. For the Einsten-Maxwell-? theory we prove that ?2 should have a U(1) isometry, a rigidity theorem in this class of solutions. We also construct all d dimensional Einstein vacuum solutions with SO(2,2) × U(1) d-4 isometry.

Sadeghian, S.; Sheikh-Jabbari, M. M.; Yavartanoo, H.

2014-10-01

155

Direct sulfation reaction of SO 2 with calcium carbonate  

Microsoft Academic Search

The direct sulfation reaction of SO2 with CaCO3 has been investigated by thermogravimetry (TG) under the condition that the CaCO3 does not decompose to CaO prior to sulfation by controlling CO2 partial pressure. The direct sulfation process can be described by using a shrinking-core model for constant particle size. The model shows that the reaction rate and the diffusion rate

Qin Zhong

1995-01-01

156

Soil acidification in China: is controlling SO2 emissions enough?  

PubMed

Facing challenges of increased energy consumption and related regional air pollution, China has been aggressively implementing flue gas desulfurization (FGD) and phasing out small inefficient units in the power sector in order to achieve the national goal of 10% reduction in sulfur dioxide (SO(2)) emissions from 2005 to 2010. In this paper, the effect of these measures on soil acidification is explored. An integrated methodology is used, combining emission inventory data, emission forecasts, air quality modeling, and ecological sensitivities indicated by critical load. National emissions of SO(2), oxides of nitrogen (NO(X)), particulate matter (PM), and ammonia (NH(3)) in 2005 were estimated to be 30.7, 19.6, 31.3, and 16.6 Mt, respectively. Implementation of existing policy will lead to reductions in SO(2) and PM emissions, while those of NO(X) and NH(3) will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur (S) deposition was exceeded in 28% of the country's territory, mainly in eastern and south-central China. The area in exceedance will decrease to 26% and 20% in 2010 and 2020, respectively, given implementation of current plans for emission reductions. However, the exceedance of the critical load for nitrogen (N, combining effects of eutrophication and acidification) will double from 2005 to 2020 due to increased NO(X) and NH(3) emissions. Combining the acidification effects of S and N, the benefits of SO(2) reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (NO(X) and NH(3)) and deposition will be a major challenge to China, requiring policy development and technology investments. To mitigate acidification in the future, China needs a multipollutant control strategy that integrates measures to reduce S, N, and PM. PMID:19924917

Zhao, Yu; Duan, Lei; Xing, Jia; Larssen, Thorjorn; Nielsen, Chris P; Hao, Jiming

2009-11-01

157

Transport of SO 2 and aerosol over the Yellow sea  

Microsoft Academic Search

Aircraft measurements of air pollutants were made to investigate the characteristic features of long-range transport of sulfur compounds over the Yellow Sea for the periods of 26–27 April and 7–10 November in 1998, and 9–11 April and 19 June in 1999, together with aerosol measurements at the Taean background station in Korea. The overall mean concentrations of SO2, O3 and

Byung-Gon Kim; Jin-Seok Han; Soon-Ung Park

2001-01-01

158

Scale, Technique and Composition Effects in Manufacturing SO 2 Emissions  

Microsoft Academic Search

Combining two data sources on emissions with value-added and employment data, this paper constructs six data bases on sulfur\\u000a dioxide (SO2) intensities that vary across countries, sectors and years. This allows us to perform a growth decomposition exercise where\\u000a the change in world manufacturing emissions is decomposed into scale, composition and technique effects. The sample covers\\u000a the period 1990–2000, and

Jean-Marie Grether; Nicole A. Mathys; Jaime de Melo

2009-01-01

159

Evaluation Of Dry Sorbent Injection For Induct SO2 Removal  

Microsoft Academic Search

An investigation of injection of dry. calcium-based sorbents into flue as for SO2 emissions control was conducted. festing was performed in a nominal 10-inch-diameter duct using flue gas produced from the combustion of a mediumsulfur coal. The process variables of interest included the approach to adiabatic saturation temperature, the calcium-to-sulfur molar ratio, and interactions of water droplets and sorbent particles.

W. J. O'Dowd; H. W. Pennline; J. I. Joubert; S. W. Lani

1990-01-01

160

Correlations between stream sulphate and regional SO2 emissions  

USGS Publications Warehouse

The relationship between atmospheric SO2 emissions and stream and lake acidification has been difficult to quantify, largely because of the limitations of sulphur deposition measurements. Precipitation sulphate (SO4) records are mostly <5 yr in length and do not account for dry sulphur deposition. Moreover, a variable fraction of wet- and dry-deposited sulphur is retained in soils and vegetation and does not contribute to the acidity of aquatic systems. We have compared annual SO2 emissions for the eastern United States from 1976 to 1980 with stream SO4 measurements from fifteen predominantly undeveloped watersheds. We find that the two forms of sulphur are strongly correlated on a regional basis and that streams in the southeastern United States (SE) receive a smaller fraction (on average, 16%, compared with 24%) of regional sulphur emissions than do streams in the northeastern United States (NE). In addition to providing direct empirical evidence of a relationship between sulphur emissions and aquatic chemistry, these results suggest that there are significant regional differences in the fraction of deposited sulphur retained in basin soils and vegetation.The relationship between atmospheric SO//2 emissions and stream and lake acidification has been difficult to quantify, largely because of the limitations of sulphur deposition measurements. The authors have compared annual SO//2 emissions for the eastern United States from 1967 to 1980 with stream SO//4 measurements from fifteen predominantly undeveloped watersheds. They found that both the wet - and dry-deposited forms of sulphur are strongly correlated on a regional basis and that streams in the southeastern United States receive a smaller fraction (on average, 16%, compared with 24%) of regional sulphur emissions than do streams in the northeastern United States. In addition to providing direct empirical evidence of a relationship between sulphur emissions and aquatic chemistry, these results suggest that there are significant regional differences in the fraction of deposited sulphur retained in basin soils and vegetation.

Smith, R.A.; Alexander, R.B.

1986-01-01

161

On the absolute calibration of SO2 cameras  

USGS Publications Warehouse

This work investigates the uncertainty of results gained through the two commonly used, but quite different, calibration methods (DOAS and calibration cells). Measurements with three different instruments, an SO2 camera, a NFOVDOAS system and an Imaging DOAS (I-DOAS), are presented. We compare the calibration-cell approach with the calibration from the NFOV-DOAS system. The respective results are compared with measurements from an I-DOAS to verify the calibration curve over the spatial extent of the image. The results show that calibration cells, while working fine in some cases, can lead to an overestimation of the SO2 CD by up to 60% compared with CDs from the DOAS measurements. Besides these errors of calibration, radiative transfer effects (e.g. light dilution, multiple scattering) can significantly influence the results of both instrument types. The measurements presented in this work were taken at Popocatepetl, Mexico, between 1 March 2011 and 4 March 2011. Average SO2 emission rates between 4.00 and 14.34 kg s?1 were observed.

Lubcke, Peter; Bobrowski, Nicole; Illing, Sebastian; Kern, Christoph; Alvarez Nieves, Jose Manuel; Vogel, Leif; Zielcke, Johannes; Delgados Granados, Hugo; Platt, Ulrich

2013-01-01

162

On Classification of Geometries with SO(2,2) Symmetry  

E-print Network

Motivated by the Extremal Vanishing Horizon (EVH) black holes, their near horizon geometry and the EVH/CFT proposal, we construct and classify solutions with (local) SO(2,2) symmetry to four and five dimensional Einstein-Maxwell-Dilaton (EMD) theory with positive, zero or negative cosmological constant Lambda, the EMD-$\\Lambda$ theory, and also $U(1)^4$ gauged supergravity in four dimensions and $U(1)^3$ gauged supergravity in five dimensions. In four dimensions the geometries are warped product of AdS3 with an interval or a circle. In five dimensions the geometries are of the form of warped product of AdS3 and a 2d surface $\\Sigma_2$. For the Einsten-Maxwell-$\\Lambda$ theory we prove that $\\Sigma_2$ should have a U(1) isometry, a rigidity theorem in this class of solutions. We also construct all d dimensional Einstein vacuum solutions with $SO(2,2) \\times U(1)^{d-4}$ or $SO(2,2) \\times SO(d-3)$ isometry.

S. Sadeghian; M. M. Sheikh-Jabbari; H. Yavartanoo

2014-10-23

163

Towards AN Accurate Infrared Linelist for SO{_2}  

NASA Astrophysics Data System (ADS)

The "Best Theory + High-resolution Expt Data" strategy now extends from NH{_3}, CO{_2} to SO{_2} which is considered a "weed" in high resolution astronomical data analysis (such as for Herschel, SOFIA, and JWST). Refining a high quality ab initio potential energy surface (PES) with selected HITRAN data, we have made significant progress toward an accurate IR line list for SO{_2}. Similar to the situation for CO{_2}, we have achieved 0.01-0.02 cm-1 accuracy for reliable line positions. Outliers in existing HITRAN models have been identified. Compared to CO{_2}, the SO{_2} rovibrational energy levels are more difficult to converge. A pure, experimentally measured dataset (instead of HITRAN models) would greatly enhance the reliabilty of higher J/K and higher energy levels computed on the refined PES. An initial IR line list has been generated to test an ab initio dipole moment surface (DMS). Limitations, deficiencies, and future developments for both line positions and IR intensities will be discussed.

Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

2012-06-01

164

Model study of initial adsorption of SO 2 on calcite and dolomite  

NASA Astrophysics Data System (ADS)

The rate of calcareous stone degradation is to a significant extent controlled by their surface chemistry with SO 2. Initial surface sulphite is converted to a harmful gypsum upon, e.g. NO 2 catalysed oxidation. However, it has been observed by scanning electron microscopy that the lateral distributions of gypsum crystals differ between calcitic and dolomitic marbles. The first-principles density functional theory is employed to understand the origin of these fundamentally different morphologies. Here, the stability differences of surface sulphite at calcite CaCO 3 (s) and dolomite Ca xMg 1- xCO 3 (s) are determined. A qualitative difference in surface sulphite stability, favouring the former, is reported. This is taken to imply that calcitic micro-crystals embedded in a dolomitic matrix act as sinks in the surface sulphation process, controlled by SO 2 diffusion. The subsequent formation of gypsum under such conditions will not require SO 42- (aq) ion transport. This explains the homogeneous distribution of gypsum observed on the calcitic micro-crystals in dolomite. In contrast, sulphation on purely calcitic marbles never reaches such high SO 2 coverage. Rather, upon oxidation, SO 42- (aq) transport to nucleation centres, such as grain boundaries, is required for the growth of gypsum crystals.

Malaga-Starzec, Katarina; Panas, Itai; Lindqvist, Oliver

2004-01-01

165

Application of V2O5/WO3/TiO2 for Resistive-Type SO2 Sensors  

PubMed Central

A study on the application of V2O5/WO3/TiO2 (VWT) as the sensitive material for resistive-type SO2 sensor was conducted, based on the fact that VWT is a well-known catalyst material for good selective catalytic nitrogen oxide reduction with a proven excellent durability in exhaust gases. The sensors fabricated in this study are planar ones with interdigitated electrodes of Au or Pt. The vanadium content of the utilized VWT is 1.5 or 3.0 wt%. The resistance of VWT decreases with an increasing SO2 concentration in the range from 20 ppm to 5,000 ppm. The best sensor response to SO2 occurs at 400 °C using Au electrodes. The sensor response value is independent on the amount of added vanadium but dependent on the electrode materials at 400 °C. These results are discussed and a sensing mechanism is discussed. PMID:22163780

Izu, Noriya; Hagen, Gunter; Schönauer, Daniela; Röder-Roith, Ulla; Moos, Ralf

2011-01-01

166

Application of V2O5/WO3/TiO2 for resistive-type SO2 sensors.  

PubMed

A study on the application of V(2)O(5)/WO(3)/TiO(2) (VWT) as the sensitive material for resistive-type SO(2) sensor was conducted, based on the fact that VWT is a well-known catalyst material for good selective catalytic nitrogen oxide reduction with a proven excellent durability in exhaust gases. The sensors fabricated in this study are planar ones with interdigitated electrodes of Au or Pt. The vanadium content of the utilized VWT is 1.5 or 3.0 wt%. The resistance of VWT decreases with an increasing SO(2) concentration in the range from 20 ppm to 5,000 ppm. The best sensor response to SO(2) occurs at 400 °C using Au electrodes. The sensor response value is independent on the amount of added vanadium but dependent on the electrode materials at 400 °C. These results are discussed and a sensing mechanism is discussed. PMID:22163780

Izu, Noriya; Hagen, Gunter; Schönauer, Daniela; Röder-Roith, Ulla; Moos, Ralf

2011-01-01

167

Adsorption and oxidation of SO2 by graphene oxides: A van der Waals density functional theory study  

NASA Astrophysics Data System (ADS)

Carbon materials have been used for low temperature (20-150 °C) catalytic removal of SO2 from the coal-burned flue gases for a long time, but the mechanism at atomic level is still controversial. Density functional theory was used to investigate the adsorption and oxidation of SO2 on elaborated graphene oxides (GOs) to discover the insights. It is found that the hydroxyl groups on GO surface possess bi-functional effects: both enhancing the adsorption of SO2 through H-bonding interaction and reducing the reaction barrier for its oxidation to SO3. The promotion of oxidation is related to a pre-activation of the surface epoxy group. Based on Bader population, charge difference and electron localization function analysis, a charge transfer channel is proposed to explain the pre-activation.

Zhang, Huijuan; Cen, Wanglai; Liu, Jie; Guo, Jiaxiu; Yin, Huaqiang; Ning, Ping

2015-01-01

168

A review of available LC/50/ data. [on toxic gases encountered in fires  

NASA Technical Reports Server (NTRS)

Several gaseous products of pyrolysis and combustion have been evaluated for LC/50/, defined as the concentration of toxic gas in the atmosphere being inhaled by test animals that will produce death in 50% of the animals within a given time period. The products tested included CO, HCl, HF, HCN, NO2, and SO2. It was found that HCN and NO2 were consistently the most toxic of the gases reviewed, and that mice were more susceptible than rats to HCl and HF, although less susceptible than rats to NO2. Extrapolation of LC/50/ data to humans indicates that metabolic rate may be a valid basis for extrapolation when the toxicity mechanism is interference with oxygen transport and utilization, or pulmonary edema, but not when it is irritation and damage to the upper respiratory tract.

Hilado, C. J.; Cumming, H. J.

1977-01-01

169

Sulfide catalysts for reducing SO2 to elemental sulfur  

DOEpatents

A highly efficient sulfide catalyst for reducing sulfur dioxide to elemental sulfur, which maximizes the selectivity of elemental sulfur over byproducts and has a high conversion efficiency. Various feed stream contaminants, such as water vapor are well tolerated. Additionally, hydrogen, carbon monoxide, or hydrogen sulfides can be employed as the reducing gases while maintaining high conversion efficiency. This allows a much wider range of uses and higher level of feed stream contaminants than prior art catalysts.

Jin, Yun (Peking, CN); Yu, Qiquan (Peking, CN); Chang, Shih-Ger (El Cerrito, CA)

2001-01-01

170

NOBLE GASES  

EPA Science Inventory

The Noble Gases symposium, on which this report is based, provided comprehensive coverage of the noble gases. The coverage included, but was not limited to, the properties, biokinetics, bioeffects, production and release to the environment, detection techniques, standards, and ap...

171

Greenhouse Gases  

MedlinePLUS

... CFCs CO Additional Information Introduction What are greenhouse gases? Many chemical compounds present in Earth's atmosphere behave ... a greenhouse gas. Carbon Monoxide and other reactive gases Carbon monoxide (CO) is not considered a direct ...

172

Thermodynamic models of the chemistry of lunar volcanic gases  

Microsoft Academic Search

Thermodynamic models and mass balance arguments are used to constrain the chemistry of lunar volcanic gases. The results predict that lunar gases were dominated by reduced C and S gases such as CO, COS, CS2, S2. The more oxidized gases CO2 and SO2 were also important, but only in limited temperature ranges. Gases such as Cl2, CCl4, and CF4 were

1991-01-01

173

Thermodynamic models of the chemistry of lunar volcanic gases  

Microsoft Academic Search

Thermodynamic models and mass-balance arguments are used to constrain the chemistry of lunar volcanic gases. The results predict that lunar gases were dominated by reduced C and S gases such as CO, COS, CS2, S2. The more oxidized gases CO2 and SO2 were also important, but only in limited temperature ranges. Gases such as Cl2, CCl4, and CF4 were more

Bruce Fegley Jr.

1991-01-01

174

Supersite synergies improve volcanic SO2 flux monitoring  

NASA Astrophysics Data System (ADS)

Both the Etna, Italy, volcano and Piton de la Fournaise (PdF), France, volcano Supersites are monitored with networks of scanning UV spectrometers. An ongoing collaboration between INGV and IPGP researchers has led to a dynamic technology transfer of novel new data analysis procedures to both networks. This new approach has been custom built to account for the particularities of both Supersites. For the Etna Supersite, the large, continuous gas emission, wide plumes and high plume height produce significant challenges for automatic networks of scanning UV spectrometers, due to the lack of a clear sky spectrum and light dilution effects. The novel approach presented here addresses both these issues. In the case of the PdF Supersite, negligible SO2 efflux is observed apart from immediately before, during and after volcanic eruptions. This necessitates a very sensitive and precise automatic analysis in order to detect the first whiffs of SO2 which act as a precursor to eruptive activity. Exactly such a solution has been developed and is demonstrated here. The technology transfer between these two Supersites promotes synergistic advantages, improving the monitoring capacity at both sites. However, until now such synergies have come about exclusively through local support from each site and the initiative of individual researchers. The full potential of such synergies can be greatly enhanced in the future if they are fully recognised and supported within the context of the Supersite initiative.

Burton, Michael; Di Muro, Andrea

2014-05-01

175

Surface analysis of Li/SO 2 battery electrodes  

NASA Astrophysics Data System (ADS)

An XPS and SEM study of the surface of a discharged lithium anode and of an unconnected lithium sheet stored in a discharged cell of the Li/LiAsF 6/AN/SO 2 battery system is reported. The stored lithium sheet is topographically homogeneous, while the discharged anode is very inhomogeneous indicating considerable chemical variation across the surface. The major result is that sulfur compounds, of which there are several, represent but a minor portion of the film constituents at the surface. It has been supposed that, since the passivation of lithium against violent reaction with acetonitrile is caused by the addition of SO 2, the primary cell discharge product, Li 2S 2O 4, was the primary constituent of the passivating layer. This can be so only if the film on lithium is a multilayer film, with the critical passivating layer being covered by film-forming reaction products. The outer portion of the film is composed of reaction products of lithium with each and every one of the electrolyte ingredients. For the Li, O, F, C and As in this film, discharge results in important chemical state transformations. In contrast, the S chemical states change relatively little, which is perhaps indicative of a stabilizing role played by the sulfur compounds.

Anderson, C. R.; James, S. D.; Kilroy, W. P.; Lee, R. N.

176

The ground state rotational spectrum of SO 2F 2  

NASA Astrophysics Data System (ADS)

The analysis of the ground state rotational spectrum of SO 2F 2 [K. Sarka, J. Demaison, L. Margulès, I. Merke, N. Heineking, H. Bürger, H. Ruland, J. Mol. Spectrosc. 200 (2000) 55] has been performed with the Watson's Hamiltonian up to sextic terms but shows some limits due to the A and S reductions. Since SO 2F 2 is a quasi-spherical top, it can also be regarded as derived from an hypothetical XY 4 molecule. Thus we have developed a new tensorial formalism in the O(3)? Td? C2 v group chain (M. Rotger, V. Boudon, M. Loëte, J. Mol. Spectrosc. 216 (2002) 297]. We test it on the ground state of this molecule using the same experimental data (10 GHz-1 THz region, J up to 99). Both fits are comparable even if the formalisms are slightly different. This paper intends to establish a link between the classical approach and the tensorial formalism. In particular, our tensorial parameters at a given order of the development are related to the usual ones. Programs for spectrum simulation and fit using these methods are named C2 vTDS. They are freely available at the URL: http://www.u-bourgogne.fr/LPUB/c2vTDS.html.

Rotger, M.; Boudon, V.; Loëte, M.; Margulès, L.; Demaison, J.; Mäder, H.; Winnewisser, G.; Müller, H. S. P.

2003-12-01

177

Reduction of SO(2) Symmetry for Spatially Extended Dynamical Systems  

NASA Astrophysics Data System (ADS)

Spatially extended systems, such as channel or pipe flows, are often equivariant under continuous symmetry transformations, with each state of the flow having an infinite number of equivalent solutions obtained from it by a translation or a rotation. This multitude of equivalent solutions tends to obscure the dynamics of turbulence. Here we describe the "first Fourier mode slice," a very simple, easy to implement reduction of SO(2) symmetry. While the method exhibits rapid variations in phase velocity whenever the magnitude of the first Fourier mode is nearly vanishing, these near singularities can be regularized by a time-scaling transformation. We show that after application of the method, hitherto unseen global structures, for example, Kuramoto-Sivashinsky relative periodic orbits and unstable manifolds of traveling waves, are uncovered.

Budanur, Nazmi Burak; Cvitanovi?, Predrag; Davidchack, Ruslan L.; Siminos, Evangelos

2015-02-01

178

Io's Thermal Regions and Non-SO2 Spectral Features  

NASA Technical Reports Server (NTRS)

Several absorptions have been identified in the Galileo NIMS spectra of Io that are not related to SO2. [1,2]. These absorptions have band centers at 2.97, 3.15, 3.85, and 3.91 microns. There are also broad absorptions in the regions 1-1.3 and 3- 3.4 microns. Patterning noise in wavelength registration, arising from the pushbroom imaging and grating motion of the NIMS instrument have previously inhibited reliable mapping of weak absorptions. Recent improvements in techniques to remove the coherent pattern noise from the NIMS dataset have been made by Soderblom. This greatly improves the signal to noise ratio and enables mapping of weak spectral signatures such as the 3.15 micron absorption on Io.

Smythe, W. D.; Soderblom, L. A.; Lopes, R. M. C.

2003-01-01

179

Reaction of cobalt in SO2 atmospheres at elevated temperatures  

NASA Technical Reports Server (NTRS)

The reaction rate of cobalt in SO2 argon environments was measured at 650 C, 700 C, 750 C and 800 C. Product scales consist primarily of an interconnected sulfide phase in an oxide matrix. At 700 C to 800 C, a thin sulfide layer adjacent to the metal is also observed. At all temperatures, the rapid diffusion of cobalt outward through the interconnected sulfide appears to be important. At 650 C, the reaction rate slows dramatically after five minutes due to a change in the distribution of these sulfides. At 700 C and 750 C, the reaction is primarily diffusion controlled; values of diffusivity of cobalt (CoS) calculated from this work show favorable agreement with values of diffusivity of cobalt (CoS) calculated from previous sulfidation work. At 800 C, a surface step becomes rate limiting. Previously announced in STAR as N83-35104

Jacobson, N. S.; Worrell, W. L.

1984-01-01

180

Reaction of cobalt in SO2 atmospheric at elevated temperatures  

NASA Technical Reports Server (NTRS)

The reaction rate of cobalt in SO2 argon environments was measured at 650 C, 700 C, 750 C and 800 C. Product scales consist primarily of an interconnected sulfide phase in an oxide matrix. At 700 C to 800 C a thin sulfide layer adjacent to the metal is also observed. At all temperatures, the rapid diffusion of cobalt outward through the interconnected sulfide appears to be important. At 650 C, the reaction rate slows dramatically after five minutes due to a change in the distribution of these sulfides. At 700 C and 750 C the reaction is primarily diffusion controlled values of diffusivity of cobalt (CoS) calculated from this work show favorable agreement with values of diffusivity of cobalt (CoS) calculated from previous sulfidation work. At 800 C, a surface step becomes rate limiting.

Jacobson, N. S.; Worrell, W. L.

1983-01-01

181

[NOx and SO2 formation in the sintering process and influence of sintering material composition on NOx emissions].  

PubMed

NOx and SO2 formation in the sintering process and the influence of coke powder content, moisture content and adding additives on NO emissions were investigated by the sintering pot experimental method. The results showed that the combustion zone moved downward along the sintering pot after the sintering started. The NOx concentrations of all monitoring points below the combustion zone were basically the same. SO2 generated in the combustion zone was adsorbed and accumulated in the sintering materials below the zone. Then, SO2 was released by pyrolysis, and finally discharged from the outlet of sintering pot. So the significant SO2 couldn't be detected before the burning through point, and the relationship between the SO2 concentration and the sintering time displayed an inverted "V" curve. NOx produced from the sintering process was mainly thermal-NOx, and most of it was NO, the NO2 concentration was very low. Reducing the coke powder and moisture contents, or adding sintering additives could effectively reduce NOx emissions. PMID:25693368

Ren, Zhong-Pei; Zhu, Tian-Le; Zhu, Ting-Yu; Lü, Dong

2014-10-01

182

Partitioning of HNO3, H2O2 and SO2 to cloud ice: Simulations with CMAQ  

NASA Astrophysics Data System (ADS)

In the upper troposphere, gas phase species can partition to cloud ice, undergo chemical reaction and contribute to particle mass aloft, affecting chemical cycling in the atmosphere. This manuscript describes the first implementation of gas-to-cloud ice partitioning of three inorganic gases, HNO3, SO2 and H2O2, along with subsequent SO2 oxidation in the Community Multiscale Air Quality (CMAQ) chemical transport model. Four simulations are performed with CMAQv4.7.1 that include lightning production of NO for August 12th-25th of 2005 to investigate the impacts of ice chemistry on CMAQ-predicted gas phase mixing ratios and particle mass concentrations of associated species. Considerable episodic decreases, greater than 25%, in gas phase HNO3 are noted at pressures of 200-600 mb, with the largest changes at 300-400 mb. Effects are also induced on other gases in the nitrogen budget. NOx and HONO mixing ratios decrease up to 20%, but changes are generally less than 10%. Nitrate aerosol mass concentrations increase up to 0.15 ?g m-3 for the highest model layers (100 mb). We find that phase changes in nitrogen species induced by ice partitioning are sensitive to CMAQ predictions of the aerosol phase accumulation mode ammonium to sulfate ratios [NH]:[SO]. Predicted O3 concentrations do not change (<1%). No changes in H2O2, SO2, or sulfate aerosol concentrations are observed.

Marmo, Brain P.; Carlton, Annmarie G.; Henderson, Barron H.

2014-05-01

183

Electronegative gases  

SciTech Connect

Recent knowledge on electronegative gases essential for the effective control of the number densities of free electrons in electrically stressed gases is highlighted. This knowledge aided the discovery of new gas dielectrics and the tailoring of gas dielectric mixtures. The role of electron attachment in the choice of unitary gas dielectrics or electronegative components in dielectric gas mixtures, and the role of electron scattering at low energies in the choice of buffer gases for such mixtures is outlined.

Christophorou, L.G.

1981-01-01

184

PROCEEDINGS: JOINT SYMPOSIUM ON DRY SO2 AND SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGIES (1ST). VOLUME 1. FUNDAMENTAL RESEARCH AND PROCESS DEVELOPMENT  

EPA Science Inventory

Forty six papers describing recent advances in dry sorbent injection technologies for SO2 control were presented at the 1st Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies. These papers covered the following topics: fundamental research; pilot-scale devel...

185

Chemistry of Sulfur Oxides on Transition Metals. III. Oxidation of SO2 and Self-Diffusion of O, SO2, and SO3 on Pt(111)  

E-print Network

Chemistry of Sulfur Oxides on Transition Metals. III. Oxidation of SO2 and Self-Diffusion of O, SO2 to be an effective SO2 oxidation and reduction catalyst. Interest in the chemistry of sulfur oxides on transition that underlies NOx storage also operate on the sulfur oxides, so that NOx storage activity is readily poisoned

Lin, Xi

186

Modeling of SO(2) scrubbing in spray towers.  

PubMed

The present article aims at developing simple realistic models in order to describe the gaseous removal process of SO(2) by absorption with and without chemical reaction in spray towers. Effects of droplet size, droplet velocity, superficial gas velocity, liquid flow rate and tower height on the performance of such a system are theoretically predicted. Model calculations bring out some very interesting facets of gas scrubbing as functions of droplet diameter and velocity. Four distinct regimes, viz. droplet lean, dense droplet, rigid droplet and droplet inertia controlling regimes, are found important in spray scrubbing process. Model calculation also elucidates the existence of rigid droplet (sphere) for a distinct droplet size at a specific droplet velocity. Theoretical considerations reveal that best performance can be achieved in the droplet inertia-controlling regime. Effect of turbulence on scrubbing is also considered for modeling. The model development and experimental data are limited to use of water-soluble alkaline scrubbing. However, the predicted values agree reasonably well with the available experimental data at lower gas and liquid flow rates for relatively smaller droplets. Models can also be applied to any gas-liquid spray absorption process subject to the assumptions and conditions necessary to describe the specific physico-chemical hydrodynamics of the system. However, incorporation of various droplet interactions can further refine the models for better prediction of removal efficiency. PMID:17568656

Bandyopadhyay, Amitava; Biswas, Manindra N

2007-09-20

187

The Distribution and Variability of Io's SO2 Atmosphere  

NASA Astrophysics Data System (ADS)

We propose the first comprehensive analysis of archival HI Lyman-alpha images of Io acquired in four HST programs from 1997-2001. This dataset comprises the best currently available data to study some of the fundamental properties of Io's SO2 atmosphere, including spatial extent, surface pressure, origin {is the dominant source sublimation or volcanos?}, and variability. The two viable sources are both expected to be highly variable, the sublimation due to the orders of magnitude change in surface vapor pressure from day- to nightside, and the volcanos due to their inherent variability. Indeed, a preliminary look at the archival dataset as a whole confirms the presense of obvious variability for images of the same hemisphere taken at different times {Feaga et al. 2003; see also Figure 4 of the proposal}. Only a single co-added exposure of the 34 Lyman-alpha images available has been modeled previously {Strobel & Wolven 2001}, so these data are ripe for a more thorough analysis. Analysis tools for this type of HST data {STIS imaging spectroscopy} have been developed previously by the PI for a project involving atomic sulfur emission from Io {Feaga et al. 2002}. This work is timely, focused, and well within the scope of a one year, modestly-funded archival research program.

Feaga, Lori

2004-07-01

188

Subminute measurements of SO2 at low parts per trillion by volume mixing ratios in the atmosphere  

NASA Astrophysics Data System (ADS)

The continuous sulfur dioxide detector (CSD) is a sensitive instrument for reliable measurements at high time resolution in the atmosphere. This new instrument is based on a SO2 measurement technique utilizing the sulfur chemiluminescence detector, previously validated in a rigorously blind experiment sponsored by the National Science Foundation. Simplified sample handling, dénuder separation technology, and the intrinsic sensitivity and fast response of the detector permit measurement at levels below 100 parts per trillion by volume in tens of seconds with the CSD. The CSD provides a differential measurement where response from ambient SO2 is determined by the difference between air containing SO2 and air scrubbed of SO2, where both air samples contain other detectable sulfur species. Digital signal post processing with phase-locked amplification of the detector signal enhances the precision and temporal resolution of the CSD. Oversampling of the detector signal at 10 Hz permits subsequent data retrieval to be adapted to changing ambient levels by either enhancing signal to noise when sulfur dioxide levels are low or by maximizing temporal resolution of derived data when levels are high. he instrument has advantages over existing instruments based on Chromatographie separation in that the CSD provides accurate and reliable measurements at low parts per trillion by volume sulfur dioxide with high time resolution. The CSD is compact and automated and does not require cryogenic materials, making this instrument suitable for remote field locations. The high temporal resolution, specificity for SO2, and sensitivity of the CSD make it a good candidate for installation on an aircraft. Airborne studies of SO2 with a sensitive, fast time response instrument may offer new insight into the understanding of phenomena such as gas-to-particle conversion, long-range transport of pollutants, and the oxidation of biogenically produced sulfur gases.

Nicks, Dennis K., Jr.; Benner, Richard L.

2001-11-01

189

Computer simulation of an aircraft-based differential absorption and scattering system for retrieval of SO2 vertical profiles  

NASA Technical Reports Server (NTRS)

The feasibility of using the differential absorption and scattering technique from aircraft altitudes for remotely measuring the vertical distribution of SO2 was studied via a computer simulation. Particular care was taken in this simulation to use system parameters (i.e., laser energy, telescope size, etc.) which can be accommodated on an aircraft and can be realized with commercially available technology. The vertical molecular and aerosol profiles were chosen to simulate the types of profiles which might be experienced over a large city. Results are presented on the retrieval of the assumed SO2 profile which show the effects of systematic errors due to interfering gases and aerosols, as well as random errors due to shot noise in the return signal, detector and background noise, and instrument-generated noise.

Hoell, J. M., Jr.

1975-01-01

190

Effects of O3 and SO2 on leaf characteristics in soybeans grown under ambient- and enriched-carbon dioxide atmosphere  

NASA Astrophysics Data System (ADS)

The effects of two air pollutant gases (SO2 and O3) on leaf photosynthesis (PS), leaf chlorophyll (Chl), chlorophyll fluorescence transients (CFTs), leaf reflectance (LR) and canopy reflectance (CR) in soybeans (Glycine max L. Merr.) were studied under both ambient- and elevated-atmospheric (CO2) using open-top chambers. In the CO2 vs. O3 experiment, soybeans 'Clark' were exposed to charcoal filtered air (low-O3) or ambient air + 40 nL L-1(O3) (high O3) during 7 h day-1, 5 days week-1 having (CO2) of 350 (mu) L L-1 CO2 (ambient-CO2) or 500 (mu) L L-1 (enriched-CO2) for 12 h day-1. In the CO2 vs. SO2 experiment, soybeans 'Essex' were exposed to charcoal filtered air (low-SO2) or + 120 nL L-1 SO2 (high-SO2) during 5 hr day-1, 5 days week-1 having the same (CO2) as for the CO2 vs. O3 experiment. Plants were exposed to treatment gases from early growth until maturity. In the CO2 vs. O3 experiment, leaf PS, leaf Chl, and CR showed trends of reduced values under high-O3, while LR was largely unchanged. Leaf PS and CR had increased values under enriched CO2. Leaf Chl and LR were not affected by CO2 enrichment. In the CO2 vs. SO2 experiment, CFTs values indicated that the gases has no impact on the light reactions of photosynthesis. Reduction in leaf PS, leaf Chl, and CR were observed under high-SO2 while LR was unchanged. The enriched CO2 environment increased leaf PS rates but had no effect on LR and leaf Chl.

Rudorff, Bernardo F.; Mulchi, Charles L.; Lee, Edward H.; Rowland, Randy A.; Daughtry, Craig S. T.

1995-09-01

191

LABORATORY INVESTIGATION OF THE PHOTOOXIDATION AND CATALYTIC OXIDATION OF SO2  

EPA Science Inventory

The photooxidation of SO2 in irradiated auto exhaust + SO2 systems, the catalytic oxidation of SO2 in the solution droplets of hazes, clouds and fogs containing several concentrations of heavy metals (Mn(+2) and Fe(+3)), and the oxidation of SO2 in irradiated hazes and fogs conta...

192

Concentration and Recovery of SO2 from Flue Gas by Pressure Swing Adsorption  

Microsoft Academic Search

Acid rain is harmful to the environment. The cause of acid rain mainly comes from air pollutant, such as SO2, NOx, etc. Because most SO2 is emitted from power plant, the control of SO2 emission can reduce acid rain pollution. Pressure swing adsorption (PSA) is an efficient technology to concentrate and recover SO2 from flue gas. This simulation study employs

Wen-jian Huang; Chao-yuh Chen; Cheng-tung Chou

193

Blood gases  

MedlinePLUS

Blood gases are a measurement of how much oxygen and carbon dioxide are in your blood. They also determine ... taking a sample of blood from the wrist area. The health care provider will insert a small ...

194

Properties of ionic liquids absorbing SO2 and the mechanism of the absorption.  

PubMed

Room-temperature ionic liquids (ILs) have been demonstrated to absorb SO(2) efficiently. However, after absorbing a large amount of SO(2), the viscosity, the conductivity, and the density of the ILs have not been studied systematically, and the mechanism of the interaction between SO(2) and ILs is still being disputed. In this work, two kinds of ILs (task-specific ILs and normal ILs) have been studied to absorb pure SO(2) at atmospheric pressure. It is found that the viscosity, the conductivity, and the density show different behaviors between task-specific ILs and normal ILs. For the task-specific ILs to absorb SO(2), before a 0.5 mol ratio of SO(2) to IL, the viscosity and density increase, and the conductivity decreases with an increase of the mole ratio of SO(2) to IL. After that, the conductivity and density increase, and the viscosity decreases with further increasing the mole ratio of SO(2) to IL. However, for the normal ILs, the conductivity and density increase and the viscosity decreases with an increase of the mole ratio of SO(2) to IL. A new mechanism of ILs absorbing SO(2) has been proposed. Task-specific ILs can chemically absorb SO(2) when the mole ratio of SO(2) to IL is not more than 0.5, and they can physically absorb SO(2) when the mole ratio is more than 0.5. The normal ILs can only physically absorb SO(2). PMID:20095593

Ren, Shuhang; Hou, Yucui; Wu, Weize; Liu, Qingya; Xiao, Yunfei; Chen, Xiaoting

2010-02-18

195

Variation of stratospheric NO2 during the solar eclipse  

NASA Technical Reports Server (NTRS)

The numerical modeling of the changes of the concentration of trace gases in the atmosphere during the eclipse shows that the NO2 total content in the vertical column increases approximately by 80 percent. The first observations of the NO2 total content during the eclipse of 1981 have given 60 plus or minus 20 percent. In the observations of 1990 the more precise methods and instruments for stratospheric NO2 measurements were used. The surface ozone, NO, and NO2 concentrations were under control. The results of the observations give the increasing of the stratospheric NO2 during the eclipse by 55 plus or minus 6 percent. The maximum increasing of the NO2 content is observed at the moment of the maximum phase.

Elansky, Nikolay F.; Elokhov, Alexander S.

1994-01-01

196

PROCEEDINGS: JOINT SYMPOSIUM ON DRY SO2 AND SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGIES (1986). VOLUME 2. ECONOMICS, POWER PLANT INTERGRATION AND COMMERICAL APPLICATIONS  

EPA Science Inventory

The proceedings document the 1986 Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies, held in Raleigh, NC, June 2-6, 1986. Fortynine papers were presented by EPA and EPRI staff members representing utility companies, equipment manufacturers, sorbent supplier...

197

PROCEEDINGS: JOINT SYMPOSIUM ON DRY SO2 AND SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGIES (1986). VOLUME 1. SORBENTS, PROCESS RESEARCH, AND DISPERSION  

EPA Science Inventory

The proceedings document the 1986 Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies, held in Raleigh, NC, June 2-6, 1986. Fortynine papers were presented by EPA and EPRI staff members representing utility companies, equipment manufacturers, sorbent supplier...

198

PROCEEDINGS: JOINT SYMPOSIUM ON DRY SO2 AND SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGIES (1ST): VOLUME 2. POWER PLANT INTEGRATION, ECONOMICS, AND FULL-SCALE EXPERIENCE  

EPA Science Inventory

The proceedings document the First Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies, held November 13-16, 1984, in San Diego, CA. The symposium, sponsored jointly by EPRI and EPA, was the first meeting of its kind devoted solely to the discussion of emissi...

199

Atmospheric gases  

NSDL National Science Digital Library

Which gases make up the atmosphere? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to the gaseous components of the atmosphere. Students explore the main gases of the atmosphere using a pop-up pie chart. Descriptions of the gases and their percentages in the atmosphere are provided. Students read about water vapor in the atmosphere, and an animation shows a simplified process of precipitation. A pop-up window explains the effects of dust on the atmosphere, and a photograph shows how large amounts of dust in the atmosphere create the reds and oranges displayed in sunsets. Finally, ozone is introduced to students as a necessary component of human life on Earth. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

200

EXPERIMENTAL AIR EXCLUSION SYSTEM FOR FIELD STUDIES OF SO2 EFFECTS ON CROP PRODUCTIVITY  

EPA Science Inventory

The Tennessee Valley Authority (TVA) characterized and quantified relationships among sulfur dioxide (SO2) exposure, symptomatology of injury, and yield of soybean crops, which are sensitive to SO2 and economically important to the southeastern United States. Characterization inc...

201

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, and flow rate.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Standard missing data procedures for SO2, NOX, and flow rate... CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2 , NOX , and flow...

2012-07-01

202

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, and flow rate.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Standard missing data procedures for SO2, NOX, and flow rate... CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2 , NOX , and flow...

2014-07-01

203

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, and flow rate.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Standard missing data procedures for SO2, NOX, and flow rate... CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2 , NOX , and flow...

2011-07-01

204

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, and flow rate.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standard missing data procedures for SO2, NOX, and flow rate... CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2 , NOX , and flow...

2013-07-01

205

Development of an ultra-violet digital camera for volcanic SO2 imaging  

Microsoft Academic Search

In an effort to improve monitoring of passive volcano degassing, we have constructed and tested a digital camera for quantifying the sulfur dioxide (SO2) content of volcanic plumes. The camera utilizes a bandpass filter to collect photons in the ultra-violet (UV) region where SO2 selectively absorbs UV light. SO2 is quantified by imaging calibration cells of known SO2 concentrations. Images

G. J. S. Bluth; J. M. Shannon; I. M. Watson; A. J. Prata; V. J. Realmuto

2007-01-01

206

Flux of SO2 into Leaf Cells and Cellular Acidification by SO21  

PubMed Central

A comparison of fluxes of SO2 from the atmosphere into leaves with fluxes across biomembranes revealed that, apart from the cuticle, the main barrier to SO2 entry into leaves are the stomates. SO2 fluxes into leaves can be calculated with an accuracy sufficient for many purposes on the assumption that the intracellular SO2 concentration is zero. SO2 entering green leaf cells is trapped in the cytoplasm. In the light, the products formed in its reaction with water are processed particularly in the chloroplasts. Flux of SO2 to the acidic central vacuole of leaf cells is insignificant. Intracellular acidification of barley mesophyll protoplasts by SO2 was measured by the uptake of 14C-labeled 5,5-dimethyl-oxazolidine-2,4-dione. The measured acidification was similar to the acidification calculated from known buffer capacities and the rate of SO2 influx when the H+/SO2 ratio was assumed to be 2. A comparison of photosynthesis inhibition by SO2 with calculated acidification revealed different mechanisms of inhibition at low and at high concentrations of SO2. At very low concentrations, inhibition by SO2 was even smaller than expected from calculated acidification. The data suggest that, if acidification cannot be compensated by pH-stabilizing cellular mechanisms, it is a main factor of SO2 toxicity at low SO2 levels. At high levels of SO2, anion toxicity and/or radical formation during oxidation of SO2 to sulfate may play a large role in inhibition. PMID:16665833

Pfanz, Hardy; Martinoia, Enrico; Lange, Otto-Ludwig; Heber, Ulrich

1987-01-01

207

Synthesis and characterization of the SO(2)N(3)(-), (SO(2))(2)N(3)(-), and SO(3)N(3)(-) anions.  

PubMed

SO(2) solutions of azide anions are bright yellow, and their Raman spectra indicate the presence of covalently bound azide. Removal of the solvent at -64 degrees C from CsN(3) or N(CH(3))(4)N(3) solutions produces yellow (SO(2))(2)N(3)(-) salts. Above -64 degrees C, these salts lose 1 mol of SO(2), resulting in white SO(2)N(3)(-) salts that are marginally stable at room temperature and thermally decompose to the corresponding azides and SO(2). These anions were characterized by vibrational and (14)N NMR spectroscopy and theoretical calculations. Slow loss of the solvent by diffusion through the walls of a sealed Teflon tube containing a sample of CsSO(2)N(3) in SO(2) resulted in white and yellowish single crystals that were identified by X-ray diffraction as CsSO(2)N(3).CsSO(3)N(3) with a = 9.542(2) A, b = 6.2189(14) A, c = 10.342(2) A, and beta = 114.958(4) degrees in the monoclinic space group P2(1)/m, Z = 2, and Cs(2)S(2)O(5).Cs(2)S(2)O(7).SO(2), respectively. Pure CsSO(3)N(3) was also prepared and characterized by vibrational spectroscopy. The S-N bond in SO(2)N(3)(-) is much weaker than that in SO(3)N(3)(-), resulting in decreased thermal stability, an increase in the S-N bond distance by 0.23 A, and an increased tendency to undergo rotational disorder. This marked difference is due to SO(3) being a much stronger Lewis acid (pF(-) value of 7.83) than SO(2) (pF(-) value of 3.99), thus forming a stronger S-N bond with the Lewis base N(3)(-). The geometry of the free gaseous SO(2)N(3)(-) anion was calculated at the RHF, MP2, B3LYP, and CCSD(T) levels. The results show that only the correlated methods correctly reproduce the experimentally observed orientation of the SO(2) group. PMID:12160418

Christe, Karl O; Boatz, Jerry A; Gerken, Michael; Haiges, Ralf; Schneider, Stefan; Schroer, Thorsten; Tham, Fook S; Vij, Ashwani; Vij, Vandana; Wagner, Ross I; Wilson, William W

2002-08-12

208

Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents  

Microsoft Academic Search

The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in

G. Hemmer; G. Kasper; J. Wang; G. Schaub

2002-01-01

209

Removal of NOx and SO2 in plasma reactor with water film  

Microsoft Academic Search

SO2 and NOx have become serious air pollutants in such things as photochemical smog and acid rain. In spite of an attempt to reduce the amount of SO2 and NOx emitted, the density of SO2 and NOx in the atmosphere has remained on a stable level, or even become worse. Here, we designed a novel type of a water film

Limin Dong; Shouguo Sheng; Lutao Liu; Jiaxiang Yang

2002-01-01

210

JOINT ACTION OF O3 AND SO2 IN MODIFYING PLANT GAS EXCHANGE  

EPA Science Inventory

The joint action of O3 and SO2 stress on plants was investigated. Gas exchange measurements of O3, SO2, and H2O vapor were made for garden pea. Plants were grown under controlled environments; O3, SO2, H2O vapor fluxes were evaluated with a whole-plant gas exchange chamber using ...

211

Production of NO2 from Photolysis of Peroxyacetyl Nitrate  

NASA Technical Reports Server (NTRS)

Peroxyacetyl nitrate (PAN) vapor was photolyzed at 248 nm, and the NO2 photoproduct was detected by laser-induced fluorescence. The quantum yield for the production of NO2 from PAN photolysis was determined by comparison to HNO3 photolysis data taken under identical experimental conditions. The average of data collected over a range of total pressures, precursor concentrations, and buffer gases was 0.83 +/- 0.09 for the NO2 quantum yield, where the statistical uncertainty is 2 standard deviations.

Mazely, Troy L.; Friedl, Randall R.; Sander, Stanley P.

1965-01-01

212

Monitoring shipping emissions with MAX-DOAS measurements of reactive trace gases  

NASA Astrophysics Data System (ADS)

Air pollution from ships contributes to overall air quality problems and it has direct health effects on the population in particular in coastal regions, and in harbor cities. In order to reduce the emissions the International Maritime Organisation (IMO) have tightened the regulations for air pollution. E.g. Sulfur Emission Control Areas (SECA) have been introduced where the sulfur content of marine fuel is limited. However, up to now there is no regular monitoring system available to verify that ships are complying with the new regulations. Furthermore measurements of reactive trace gases in marine environments are in general sparse. The project MeSMarT (Measurements of shipping emissions in the marine troposphere, www.mesmart.de) has been established as a cooperation between the University of Bremen and the German Bundesamt für Seeschifffahrt und Hydrographie (Federal Maritime and Hydrographic Agency) with support of the Helmholtz Research Centre Geesthacht to estimate the influence of ship emissions on the chemistry of the atmospheric boundary layer and to establish a monitoring system for main shipping routes. Here we present MAX-DOAS observations of NO2 and SO2 carried out during ship campaigns in the North and Baltic Sea and from two permanent sites close to the Elbe river (Wedel, Germany) and on the island Neuwerk close to the mouths of Elbe and Weser river. Mixing ratios of both trace gases have been retrieved using different approaches (pure geometric and taking into account the radiative transfer) and compared to in situ and air borne observations (see Kattner et al., Monitoring shipping emissions with in-situ measurements of trace gases, and Meier et al., Airborne measurements of NO2 shipping emissions using imaging DOAS) observations. Furthermore simple approaches have been used to calculate emission factors of NOx and SO2 for single ships.

Wittrock, Folkard; Peters, Enno; Seyler, André; Kattner, Lisa; Mathieu-Üffing, Barbara; Burrows, John P.; Chirkov, Maksym; Meier, Andreas C.; Richter, Andreas; Schönhardt, Anja; Schmolke, Stefan; Theobald, Norbert

2014-05-01

213

Variability of SO2, CO and light hydrocarbons over a megacity in Eastern India: effects of emissions and transport  

NASA Astrophysics Data System (ADS)

Continuous measurements of SO2 during March 2012 - February 2013 along with sampling based measurements of CO, CH4 and C2-C5 NMHCs were made over Kolkata (the world's 16th largest megacity in terms of population) to study emission characteristics over this South Asian megacity. The observed SO2 concentrations are comparable to several Asian sites but higher than American/European sites. Further, C3H8 and C4H10 are substantially higher over the study region compared to many other Asian cities. The mean SO2 and C2H6 concentrations during winter and post-monsoon periods were 5 and 3 times higher compared to pre-monsoon and monsoon. High levels of SO2 during winter (>6 ppbv) are attributed to regional emissions and subsequent trapping of these air masses favored by a stable atmosphere with low ventilation coefficient. Coal burning in industrial areas and power plants in eastern Indo-Gangetic Plains (IGP) are identified as potential source regions for SO2 during winter. Daytime elevations in SO2 during summer seem to be related to photo-oxidation of RSCs from a nearby landfill region. Early morning enhancements during winter for several trace gases indicate the role of boundary layer dynamics. Interspecies correlations show the dominant influence of LPG leakage and petrochemical industries to local air quality during winter apart from vehicular traffic. Correlation analysis shows that CO is dominated by biofuel combustions. Positive matrix factorization is used to identify different emission sources influencing the air quality over the study region. The concentrations over Kolkata may be interpreted as the end point of anthropogenic inputs to the IGP outflow into the Bay of Bengal (BoB) and subsequently the Indian Ocean during winter. Usefulness of these measurements (e.g. C2H2 to CO ratios) as initial values in calculating photochemical processing of air masses over the BoB will be discussed during the presentation. From the point of view of emission inventories, these measurements over Kolkata can have important implications towards characterizing urban Indian emissions and potentially also represent South Asia.

Mallik, C.; Ghosh, D.; Sarkar, U.; Lal, S.; Venkataramani, S.

2013-12-01

214

Simultaneous removal of NO and SO 2 with hexamminecobalt(II) solution coupled with the hexamminecobalt(II) regeneration catalyzed by activated carbon  

Microsoft Academic Search

The wet ammonia desulfurization process can be retrofitted for combined removal of SO2 and NO from the flue gases by adding soluble cobalt(II) salt into the aqueous ammonia solution. Activated carbon is used to catalyze the reduction of hexamminecobalt(III) to hexamminecobalt(II) to maintain the capability of removing NO of the hexamminecobalt solution. The effects of temperature, pH, activated carbon particle

Xiang-Li Long; Zhi-Ling Xin; Hong-Xin Wang; Wen-De Xiao; Wei-Kang Yuan

2004-01-01

215

Sulfur Dioxide Treatment from Flue Gases Using a Biotrickling  

E-print Network

Sulfur Dioxide Treatment from Flue Gases Using a Biotrickling Filter-Bioreactor System L I G Y P H of California, Riverside, California 92521 Complete treatment of sulfur dioxide (SO2) from flue gases in a two effectively treat the biotrickling filter effluent and produce elemental sulfur. The sulfur production

216

Temperature effects on the retrieval of SO2 from ultraviolet satellite observations  

NASA Astrophysics Data System (ADS)

Sulfur dioxide (SO2) has a significant impact on the urban environment pollution and global climate. Compared with regional ground monitoring networks, satellite remote sensing technology provides an unprecedented advantage for continuous, large spatial and short-revisit monitoring for atmospheric SO2. Approaches for retrieval of SO2 from ultraviolet satellite observations have been developed and applied to detection of volcanic SO2 and regional emissions. However, these retrieval algorithms do not consider the temperature variation effect on SO2 retrievals, and simply use the absorption coefficient at a constant temperature as inputs for SO2 retrievals. In this study, hyperspectral OMI measurements were used to analyze the temperature effects on the retrieval of SO2 columns. Results of DOAS algorithm showed that with increasing SO2 concentration, the retrieval errors caused by temperature effects accumulated, and the differences in SO2 columns increased to a maximum of ~25 DU (SO2 column of 293K: ~65 DU). Therefore, atmospheric temperature is an important factor which has significant influence to high precise atmospheric SO2 retrievals.

Yan, Huanhuan; Wang, Weihe; Chen, Liangfu

2014-11-01

217

Operational real-time monitoring of volcanic SO2 emission rates using an innovative SO2 camera system and sophisticated retrieval techniques (Invited)  

NASA Astrophysics Data System (ADS)

With the advent of SO2 camera systems some years ago, it became possible to image volcanic SO2 plumes at high temporal and spatial resolutions. Systems operating in the ultra-violet region measure the absorption of scattered solar radiation by SO2 in a narrow wavelength channel centered around 310 nm. A first-order correction for the effect of aerosol scattering is obtained by recording coincident images in at least one additional, off-band channel, typically centered around 330 nm. The promise of measuring SO2 emission rates at time resolutions comparable to geophysical techniques has led to increasingly widespread application of such systems. Until recently, however, a number of issues made SO2 camera systems difficult to use quantitatively for continuous monitoring. For one, UV-sensitive CCD camera technology lacked the durability required for continuous use. Also, because these camera systems collect very limited spectral information the potentially complex radiative transfer of a given scene, which can significantly impact SO2 retrievals, was not quantifiable. System calibrations were typically performed using gas cell measurements, but this approach is not valid for distant or optically thick plumes, or for plumes containing ash. Finally, the use of simple correlation techniques to derive plume velocity usually required manual input and did not take into account that the velocity typically varies throughout the plume. Together, these effects could easily lead to absolute errors of 100% or more in retrieved SO2 emission rates. Here we present solutions to these major challenges. First, we describe an SO2 camera system that uses two modern UV-sensitive CCD cameras with electronic shutters that are integrated with a moderate resolution UV spectrometer. The system software retrieves plume velocity fields in two dimensions, thus improving the accuracy of the derived SO2 emission rates while at the same time providing purposeful data for the study of plume dynamics and entrainment of ambient air. In addition, the spectrometer data are used to retrieve and correct for complex radiative transfer effects in the camera images. These techniques to improve the accuracy of retrieved SO2 emission rates were integrated into a continuous, real-time monitoring system for measuring SO2 output from Kilauea's summit vent starting in August 2013. Several examples from this exciting new dataset will be given, and the new opportunities for studying volcanic processes that such instruments provide will be illustrated.

Kern, C.; Burton, M. R.; Elias, T.; Luebcke, P.; Mori, T.; Esposti Ongaro, T.; Prata, F.; Sutton, A. J.; Tamburello, G.; Werner, C. A.

2013-12-01

218

Greenhouse Gases  

NSDL National Science Digital Library

This is a lesson where learners engage in a radiating heat activity and an activity that measures temperature in models with and without greenhouse gases. Learners will draw conclusions about the effect of greenhouse gases on temperature and on human life and kinesthetically model the absorbing and re-radiation of heat. The lesson models scientific inquiry using the 5E instructional model and includes teacher notes, prerequisite concepts, common misconceptions, student journal and reading. This is lesson 3 in the Astro-Venture Atmospheric Science Training Unit. The purpose of the unit is to increase students’ awareness of and interest in astrobiology and the many career opportunities that utilize science, math and technology skills. The lessons are designed for educators to use in conjunction with the Astro-Venture multimedia modules.

219

SPECIAL EDITION VOLUME 15 NO.2 SPECIAL EDITION2 VOLUME 15 No.2 SPECIAL EDITION VOLUME 15 No.2  

E-print Network

SPECIAL EDITION VOLUME 15 NO.2 #12;SPECIAL EDITION2 VOLUME 15 No.2 SPECIAL EDITION VOLUME 15 No.2;THENATIONALHIGHMAGNETICFIELDLABORATORYSCIENCECOUNCIL SPECIAL EDITION VOLUME 15 No.2 SPECIAL EDITION VOLUME 15 No.2 5 Herearethevitalstatisticsforthe

Weston, Ken

220

Adsorption characteristics of SO2 on activated carbon prepared from coconut shell with potassium hydroxide activation.  

PubMed

The adsorption characteristics of SO2 were studied with KOH-impregnated granular activated carbon (K-IAC). To confirm selective SO2 adsorptivity of K-IAC using a fixed bed adsorption column, experiments were conducted on the effects of KOH and of linear velocity, temperature, and concentration. In addition, changes in features before and after adsorption were observed by utilizing FTIR, XRD, ToF-SIMS, and AES/SAM, examining the surface chemistry. K-IAC adsorbed 13.2 times more SO2 than did general activated carbon (GAC). The amount of SO2 adsorbed increased as linear velocity and concentration increased and as temperature decreased. At lower temperature, the dominant reaction between KOH and SO2 produces K2-SO3 and H2O. Any H2O remaining on the surface is converted into H2SO4 as SO2 and O2 are introduced. Then, the KOH and SO2 reaction produces K2SO4 and H2O. The surface characterization results proved that adsorption occurred through chemical reaction between KOH and SO2. The SO2 adsorbed K-IAC exists in the form of stable oxide crystal, K2SO3 and K2SO4, due to potassium. The basic feature given to the surface of activated carbon by KOH impregnation was confirmed to be acting as the main factor in enhancing SO2 adsorptivity. PMID:11917995

Lee, Young-Whan; Park, Jin-Won; Choung, Jae-Hoon; Choi, Dae-Ki

2002-03-01

221

Hydrophobic task-specific ionic liquids: synthesis, properties and application for the capture of SO2.  

PubMed

The capture of SO2 by ionic liquids (ILs) has drawn much attention all over the world. However, ILs can absorb not only SO2 but also water from flue gas. The removal of water from ILs is necessary for reusing the absorbent. In order to reduce the energy costs of removing water, it would be helpful to weaken the interactions between ILs and water. In this work, two kinds of hydrophobic task-specific ILs, 1-(2-diethyl-aminoethyl)-3-methylimidazolium hexafluorophosphate ([Et2NEmim] [PF6]) and 1-(2-diethyl-aminoethyl)-1-methylpyrrolidinium hexafluorophosphate ([Et2NEmpyr][PF6]), were designed and synthesized. Thermal stability and physical properties of the ILs were studied. Furthermore, the application of the ILs for the capture of SO2 and the absorption mechanism were systematically investigated. It has been found that both of the ILs are immiscible with water, and [Et2NEmim][PF6] has much lower viscosity, much higher thermal stability and much higher SO2 absorption rate than [Et2NEmpyr][PF6]. [Et2NEmim][PF6] shows high SO2 absorption capacities up to 2.11 mol SO2 per mole IL (pure SO2) and 0.94 mol SO2 per mole IL (3% SO2) under hydrous conditions at 30 °C. The result suggests that [Et2NEmim][PF6] is a promising recyclable absorbent for the capture of SO2. PMID:24998204

Tian, Shidong; Hou, Yucui; Wu, Weize; Ren, Shuhang; Qian, Jianguo

2014-08-15

222

Meteorological influence on predicting surface SO2 concentration from satellite remote sensing in Shanghai, China.  

PubMed

In this study, we explored the potential applications of the Ozone Monitoring Instrument (OMI) satellite sensor in air pollution research. The OMI planetary boundary layer sulfur dioxide (SO2_PBL) column density and daily average surface SO2 concentration of Shanghai from 2004 to 2012 were analyzed. After several consecutive years of increase, the surface SO2 concentration finally declined in 2007. It was higher in winter than in other seasons. The coefficient between daily average surface SO2 concentration and SO2_PBL was only 0.316. But SO2_PBL was found to be a highly significant predictor of the surface SO2 concentration using the simple regression model. Five meteorological factors were considered in this study, among them, temperature, dew point, relative humidity, and wind speed were negatively correlated with surface SO2 concentration, while pressure was positively correlated. Furthermore, it was found that dew point was a more effective predictor than temperature. When these meteorological factors were used in multiple regression, the determination coefficient reached 0.379. The relationship of the surface SO2 concentration and meteorological factors was seasonally dependent. In summer and autumn, the regression model performed better than in spring and winter. The surface SO2 concentration predicting method proposed in this study can be easily adapted for other regions, especially most useful for those having no operational air pollution forecasting services or having sparse ground monitoring networks. PMID:24362515

Xue, Dan; Yin, Jingyuan

2014-05-01

223

The influence of reaction conditions on SO2 oxidation in a discharge plasma reactor  

Microsoft Academic Search

In this paper, experimental approaches have been carried out to investigate the removal of sulfur dioxide (SO2) using pulsed discharge nonthermal plasma in the absence of ammonia (NH3). The gas-phase reaction was found to be less attractive due to its large energy cost. The increase in temperature decreased the SO2 removal rate, resulting in large energy cost. SO2 removal was

Hyun Ha Kim; Chunxi Wu; Youhei Kinoshita; Kazunori Takashima; Shinji Katsura; Akira Mizuno

2001-01-01

224

Band residual difference algorithm for retrieval of SO2 from the aura ozone monitoring instrument (OMI)  

Microsoft Academic Search

The Ozone Monitoring Instrument (OMI) on EOS\\/Aura offers unprecedented spatial and spectral resolution, coupled with global coverage, for space-based UV measurements of sulfur dioxide (SO2). This paper describes an OMI SO2 algorithm (the band residual difference) that uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3). By using optimum wavelengths for retrieval of

Nickolay A. Krotkov; Simon A. Carn; Arlin J. Krueger; Pawan K. Bhartia; Kai Yang

2006-01-01

225

SO2 along the western border of Pennsylvania: An analysis of temporal variability and transport pathways  

Microsoft Academic Search

Sulfur Dioxide (SO2) is emitted from combustion of sulfur-containing fuels and from the smelting of sulfur- containing ores. Within the United States, the Mid-Atlantic region receives the highest sulfuric acid and sulfate loadings. This study describes atmospheric SO2 variability and transport pathways in the western Pennsylvania border region. SO2 variability during 2004 was examined at seven EPA ground-based monitoring sites

J. A. Snow; D. C. Fujii; J. Livingston; M. C. Batina

2006-01-01

226

Oxidation of volcanic SO2: A sink for stratospheric OH and H2O  

Microsoft Academic Search

The oxidation of volcanic SO2 to sulfate in the stratosphere is investigated for an anomalously large volcanic sulfur loading (approximately 200 Mt) similar to that generated by the Tambora eruption in 1815. Model calculations suggest that stratospheric OH levels can be severely reduced by the gas-phase oxidation of SO2. One implication of this is that dense volcanic SO2 clouds may

S. Bekki

1995-01-01

227

A technique for monitoring SO2 in combustion exhausts: Use of a non-Nernstian sensing element in combination with an upstream catalytic filter  

SciTech Connect

Detection of sulfur dioxide (SO2) at high temperature (600 750 oC) in the presence of some interferents found in typical combustion exhausts (oxides of nitrogen (NO2 and NO, "NOx"), CO2, CO, and hydrocarbon (C3H6)) is described. The detection scheme involves use of a catalytic filter in front of a non-Nernstian sensing element. The catalytic filter was a Ni:Cr powder bed operating at 850 oC and the sensing elements were pairs of platinum (Pt) and oxide (Ba-promoted copper chromite ((Ba,Cu)xCryOz) and Sr-modified lanthanum ferrite (LSF)) electrodes on yttria-stabilized zirconia. The Ni:Cr powder bed was capable of reducing the sensing element response to NOx, CO, and C3H6, but the presence of NOx (100 ppm by volume) still interfered with the SO2 response of the Pt-(Ba,Cu)xCryOz sensing element at 600 oC, causing approximately a 7 mV (20%) reduction in the response to 120 ppm SO2 and a response equivalent to about 20 ppm SO2 in the in the absence of SO2. The Pt-LSF sensing element, operated at 750 oC, did not suffer from this NOx interference but at the cost of a reduced SO2 response magnitude (120 ppm SO2 yielded ~10 mV, in contrast to ~30 mV for the Pt-(Ba,Cu)xCryOz sensing element). The powder bed and Pt-LSF sensing element were operated continuously over approximately 350 hours, and the response to SO2 drifted downward by about 7%, with most of this change occurring during the initial 100 hours of operation.

West, David L [ORNL; Montgomery, Fred C [ORNL; Armstrong, Timothy R. [ORNL

2009-01-01

228

Production of negative ions by dissociative electron attachment to SO2  

NASA Technical Reports Server (NTRS)

Dissociative electron attachment cross section measurements for the production of O(-), S(-), and SO(-) have been performed utilizing a crossed target SO2 molecule beam-electron beam geometry. The relative flow technique is employed to determine the absolute values of cross sections. The attachment energies corresponding to various cross section maxima are: 4.30 and 7.1 eV for O(-)/SO2; 4.0, 7.5, and 8.9 eV for S(-)/SO2, and 4.7 and 7.5 eV for SO(-)/SO2.

Orient, O. J.; Srivastava, S. K.

1983-01-01

229

The influence of emission sources and meteorological conditions on SO2 pollution in Mongolia  

NASA Astrophysics Data System (ADS)

Major urbanization and industrialization began in Mongolia in the mid-1990, and air pollution has since become a challenging environmental problem. This study used air pollution data and meteorological parameters from fourteen monitoring sites to determine spatial and temporal patterns of SO2 in Mongolia from 1996 to 2009 and to estimate the influence of meteorological parameters such as wind speed and direction, temperature and relative humidity on SO2 levels in Ulaanbaatar city from 2005 to 2009. SO2 pollution in urban areas and at the steel industry site was above the National Ambient Air Quality Standard and more serious than at other locations in Mongolia. SO2 pollution in winter was more serious than the other three seasons in Mongolia. SO2 pollution has worsened since 2000 because of rapid urbanization and industrialization. Multiple regression models showed that SO2 concentrations in Ulaanbaatar increased with the decrease of wind speed and temperature, and with the increase of relative humidity. The increase in SO2 pollution in Ulaanbaatar was associated with flow of SOx emitted from industrial sources and gers to the north of the city. This study concludes that SO2 pollution in Mongolia was worsened by the increase in emissions caused by rapid urbanization and industrialization over the last decade and the dispersion of SO2 concentrations in Ulaanbaatar was influenced by the meteorological parameters wind speed and direction, temperature and relative humidity.

Luvsan, Munkh-Erdene; Shie, Ruei-Hao; Purevdorj, Tseden; Badarch, Lkhagvasuren; Baldorj, Barkhasragchaa; Chan, Chang-Chuan

2012-12-01

230

Adsorption of SO2 on bituminous coal char and activated carbon fiber  

USGS Publications Warehouse

The SO2 adsorption behaviors of activated carbons produced from Illinois coal and of commercially prepared activated carbon fibers (ACFs) were compared. There was no relation between surface area of coal-based carbons and SO2 adsorption, whereas adsorption of SO2 on the series of ACFs was inversely proportional to N2 BET surface area. Higher surface area ACFs had wider pores and adsorbed less SO2; thus, pore size distribution is thought to play a significant role in SO2 adsorption for these materials. Oxidation with HNO3 and/or H2SO4, followed by heat treatment at 700-925 ??C to remove carbon-oxygen complexes, resulted in increased SO2 adsorption for both coal chars and ACFs. This behavior was explained by an increase in the available number of free sites, previously occupied by oxygen and now available for SO2 adsorption. The use of nitrogen-containing functional groups on ACFs of proper pore size shows promise for further increasing SO2 adsorption capacities. Knowledge of the relationship among the number of free sites, pore size, and surface chemistry on corresponding SO2 adsorption should lead to the development of more efficient adsorbents prepared from either coal or ACFs.

DeBarr, J.A.; Lizzio, A.A.; Daley, M.A.

1997-01-01

231

Sulfur chemistry in the Venus mesosphere from SO 2 and SO microwave spectra  

NASA Astrophysics Data System (ADS)

First measurements of SO 2 and SO in the Venus mesosphere (70-100 km) are reported. This altitude range is distinctly above the ˜60-70 km range to which nadir-sounding IR and UV investigations are sensitive. Since July 2004, use of ground-based sub-mm spectroscopy has yielded multiple discoveries. Abundance of each molecule varies strongly on many timescales over the entire sub-Earth Venus hemisphere. Diurnal behavior is evident, with more SO 2, and less SO, at night than during the day. Non-diurnal variability is also present, with measured SO 2 and SO abundances each changing by up to 2× or more between observations conducted on different dates, but at fixed phase, hence identical sub-Earth Venus local times. Change as large and rapid as a 5 ? doubling of SO on a one-week timescale is seen. The sum of SO 2 and SO abundances varies by an order of magnitude or more, indicating at least one additional sulfur reservoir must be present, and that it must function as both a sink and source for these molecules. The ratio SO 2/SO varies by nearly two orders of magnitude, with both diurnal and non-diurnal components. In contrast to the strong time dependence of molecular abundances, their altitude distributions are temporally invariant, with far more SO 2 and SO at 85-100 km than at 70-85 km. The observed increase of SO 2 mixing ratio with altitude requires that the primary SO 2 source be upper mesospheric photochemistry, contrary to atmospheric models which assert upward transport as the only source of above-cloud SO 2. Abundance of upper mesospheric aerosol, with assumption that it is composed primarily of sulfuric acid, is at least sufficient to provide the maximum gas phase (SO + SO 2) sulfur reported in this study. Sulfate aerosol is thus a plausible source of upper mesospheric SO 2.

Sandor, Brad J.; Todd Clancy, R.; Moriarty-Schieven, Gerald; Mills, Franklin P.

2010-07-01

232

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2014 CFR

...estimating hourly SO2 mass emissions if the affected unit qualifies as a low mass emissions unit under...operator may determine SO2 mass emissions by using a certified...the span value or ±5 ppm, whichever is less restrictive...linearity and relative accuracy test audit)....

2014-07-01

233

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2012 CFR

...estimating hourly SO2 mass emissions if the affected unit qualifies as a low mass emissions unit under...operator may determine SO2 mass emissions by using a certified...the span value or ±5 ppm, whichever is less restrictive...linearity and relative accuracy test audit)....

2012-07-01

234

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2011 CFR

...estimating hourly SO2 mass emissions if the affected unit qualifies as a low mass emissions unit under...operator may determine SO2 mass emissions by using a certified...the span value or ±5 ppm, whichever is less restrictive...linearity and relative accuracy test audit)....

2011-07-01

235

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2010 CFR

...estimating hourly SO2 mass emissions if the affected unit qualifies as a low mass emissions unit under...operator may determine SO2 mass emissions by using a certified...the span value or ±5 ppm, whichever is less restrictive...linearity and relative accuracy test audit)....

2010-07-01

236

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2013 CFR

...estimating hourly SO2 mass emissions if the affected unit qualifies as a low mass emissions unit under...operator may determine SO2 mass emissions by using a certified...the span value or ±5 ppm, whichever is less restrictive...linearity and relative accuracy test audit)....

2013-07-01

237

FUNDAMENTAL STUDIES OF SORBENT CALCINATION AND SULFATION FOR SO2 CONTROL FROM COAL-FIRED BOILERS  

EPA Science Inventory

The report gives results of a laboratory-scale investigation of the reactivity of calcium-based sorbents for SO2 capture after calcination at furnace operating temperatures (1200-1950 C). This work was undertaken to provide fundamental information for developing SO2 emission cont...

238

40 CFR 97.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2010 CFR

...a CAIR SO2 source subject to an Acid Rain emissions limitation, the Administrator...CAIR SO2 source not subject to an Acid Rain emissions limitation, the Administrator...if the source is subject to an Acid Rain emissions limitation, the...

2010-07-01

239

CONTROLLING SO2 EMISSIONS: A REVIEW OF TECHNOLOGIES (EPA/600/R-00/093)  

EPA Science Inventory

Sulfur dioxide (SO2) scrubbers may be used by electricity generating units to meet the requirements of Phase II of the Acid Rain SO2 Reduction Program. Additionally, the use of scrubbers can result in reduction of mercury and particulate matter emissions. It is timely, therefore...

240

40 CFR 96.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2011 CFR

...a CAIR SO2 source subject to an Acid Rain emissions limitation, the Administrator...CAIR SO2 source not subject to an Acid Rain emissions limitation, the Administrator...if the source is subject to an Acid Rain emissions limitation, the...

2011-07-01

241

40 CFR 96.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2012 CFR

...a CAIR SO2 source subject to an Acid Rain emissions limitation, the Administrator...CAIR SO2 source not subject to an Acid Rain emissions limitation, the Administrator...if the source is subject to an Acid Rain emissions limitation, the...

2012-07-01

242

40 CFR 97.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2011 CFR

...a CAIR SO2 source subject to an Acid Rain emissions limitation, the Administrator...CAIR SO2 source not subject to an Acid Rain emissions limitation, the Administrator...if the source is subject to an Acid Rain emissions limitation, the...

2011-07-01

243

PROJECT SUMMARY: CONTROLLING SO2 EMISSIONS: A REVIEW OF TECHNOLOGIES (EPA/600/SR-00/093)  

EPA Science Inventory

Sulfur dioxide (SO2) scrubbers may be used by electricity generating units to meet the requirements of Phase II of the Acid Rain SO2 Reduction Program. Additionally, the use of scrubbers can result in reduction of mercury and particulate matter emissions. It is timely, therefore,...

244

Dynamic adsorption on activated carbons of SO 2 traces in air  

Microsoft Academic Search

Sulphur dioxide is an atmospheric pollutant which, among numerous others, has to be eliminated by habitacle filters. Breakthrough curves of low concentration SO2 streams through beds of activated carbons have been obtained. Two carbons were studied, an activated PAN fiber (CF) and a granulated activated carbon (CN) under SO2 concentrations lower than 100 ppm. Carbon CN used ‘as received’ is

C. Martin; A. Perrard; J. P. Joly; F. Gaillard; V. Delecroix

2002-01-01

245

SO2 measurements at a high altitude site in the central Himalayas: Role of regional transport  

NASA Astrophysics Data System (ADS)

Continuous measurements of a climatically important acidic gas, SO2, were made over Nainital (29.37°N, 79.45°E; 1958 m amsl), a regionally representative site in the central Himalayas, for the first time during 2009-2011. Unlike many other sites, the SO2 levels over Nainital are higher during pre-monsoon (345 pptv) compared to winter (71 pptv). High values during pre-monsoon are attributed to the transport of air masses from regions viz. Indo-Gangetic Plain (IGP), northern India and north-East Pakistan, which are dotted with numerous industries and power plants, where coal burning occurs. Transport from the polluted regions is evinced from good correlations of SO2 with wind speed, NOy and UV aerosol index during these periods. Daytime elevations in SO2 levels, influenced by 'valley winds' and boundary layer evolution, is a persistent feature at Nainital. SO2 levels are very much lower during monsoon compared to pre-monsoon, due to oxidation losses and wet scavenging. Despite this, SO2/NOy slopes are high (>0.4) both during pre-monsoon and monsoon, indicating impacts of point sources. The SO2 levels during winter are lower as the measurement site is cut off from the plains due to boundary layer dynamics. Further, the SO2 levels during winter nights are the lowest (lesser than 50 pptv) and resemble free tropospheric conditions.

Naja, Manish; Mallik, Chinmay; Sarangi, Tapaswini; Sheel, Varun; Lal, Shyam

2014-12-01

246

USE OF COAL CLEANING FOR COMPLIANCE WITH SO2 EMISSION REGULATIONS  

EPA Science Inventory

The report gives results of an evaluation of coal cleaning as a means of controlling SO2 emissions from coal-fired stationary sources. Coal cleaning was examined in the light of various existing and proposed SO2 emissions regulations to determine applications in which the technol...

247

CALCINATION OF CALCIUM HYDROXIDE SORBENT IN THE PRESENCE OF SO2 AND ITS EFFECT ON REACTIVITY  

EPA Science Inventory

The paper discusses the calcination of Ca(OH)2 sorbent in the presence of SO2 and its effect on reactivity. When Ca(0H)2 is calcined in an isothermal flow reactor with 300 ppm or less SO2, the structure of the sorbent is characterized by retention of higher pore volumes and surfa...

248

Massive Volcanic SO2 Oxidation and Sulphate Aerosol Deposition in Cenozoic North America  

EPA Science Inventory

Volcanic eruptions release a large amount of sulphur dioxide (SO2) into the atmosphere. SO2 is oxidized to sulphate and can subsequently form sulphate aerosol, which can affect the Earth's radiation balance, biologic productivity and high-altitude ozone co...

249

40 CFR 96.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2010 CFR

...sulfur dioxide emissions, determined in accordance with subpart HHH of this part, from all CAIR SO2 units at the source for the...sulfur dioxide emissions, determined in accordance with subpart HHH of this part, from all CAIR SO2 units at the source for...

2010-07-01

250

Next Generation Aura-OMI SO2 Retrieval Algorithm: Introduction and Implementation Status  

NASA Technical Reports Server (NTRS)

We introduce our next generation algorithm to retrieve SO2 using radiance measurements from the Aura Ozone Monitoring Instrument (OMI). We employ a principal component analysis technique to analyze OMI radiance spectral in 310.5-340 nm acquired over regions with no significant SO2. The resulting principal components (PCs) capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering, and ozone absorption) and measurement artifacts, enabling us to account for these various interferences in SO2 retrievals. By fitting these PCs along with SO2 Jacobians calculated with a radiative transfer model to OMI-measured radiance spectra, we directly estimate SO2 vertical column density in one step. As compared with the previous generation operational OMSO2 PBL (Planetary Boundary Layer) SO2 product, our new algorithm greatly reduces unphysical biases and decreases the noise by a factor of two, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing long-term, consistent SO2 records for air quality and climate research. We have operationally implemented this new algorithm on OMI SIPS for producing the new generation standard OMI SO2 products.

Li, Can; Joiner, Joanna; Krotkov, Nickolay A.; Bhartia, Pawan K.

2014-01-01

251

40 CFR 60.42b - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Standard for sulfur dioxide (SO2). 60.42b Section...Generating Units § 60.42b Standard for sulfur dioxide (SO2). (a) Except...facility combusts oil other than very low sulfur oil. Percent reduction...

2010-07-01

252

40 CFR 60.42c - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2014 CFR

... 2014-07-01 false Standard for sulfur dioxide (SO2). 60.42c Section...Generating Units § 60.42c Standard for sulfur dioxide (SO2 ). (a) Except...contains greater than 0.5 weight percent sulfur. The percent reduction requirements...

2014-07-01

253

40 CFR 60.42b - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2014 CFR

... 2014-07-01 false Standard for sulfur dioxide (SO2). 60.42b Section...Generating Units § 60.42b Standard for sulfur dioxide (SO2 ). (a) Except...facility combusts oil other than very low sulfur oil. Percent reduction...

2014-07-01

254

40 CFR 60.43Da - Standards for sulfur dioxide (SO2).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standards for sulfur dioxide (SO2). 60.43Da Section...Generating Units § 60.43Da Standards for sulfur dioxide (SO2 ). (a) On...determined on a 24-hour basis. (d) Sulfur dioxide emissions are limited to 520...

2013-07-01

255

40 CFR 60.43Da - Standards for sulfur dioxide (SO2).  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Standards for sulfur dioxide (SO2). 60.43Da Section...Generating Units § 60.43Da Standards for sulfur dioxide (SO2 ). (a) On...determined on a 24-hour basis. (d) Sulfur dioxide emissions are limited to 520...

2014-07-01

256

40 CFR 60.42b - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Standard for sulfur dioxide (SO2). 60.42b Section...Generating Units § 60.42b Standard for sulfur dioxide (SO2). (a) Except...facility combusts oil other than very low sulfur oil. Percent reduction...

2012-07-01

257

40 CFR 60.42c - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Standard for sulfur dioxide (SO2). 60.42c Section...Generating Units § 60.42c Standard for sulfur dioxide (SO2). (a) Except...contains greater than 0.5 weight percent sulfur. The percent reduction requirements...

2012-07-01

258

40 CFR 60.42b - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Standard for sulfur dioxide (SO2). 60.42b Section...Generating Units § 60.42b Standard for sulfur dioxide (SO2 ). (a) Except...facility combusts oil other than very low sulfur oil. Percent reduction...

2013-07-01

259

40 CFR 60.43Da - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Standard for sulfur dioxide (SO2). 60.43Da Section...18, 1978 § 60.43Da Standard for sulfur dioxide (SO2). (a) On and...determined on a 24-hour basis. (d) Sulfur dioxide emissions are limited to 520...

2011-07-01

260

SO2 along the western border of Pennsylvania: An analysis of temporal variability and transport pathways  

NASA Astrophysics Data System (ADS)

Sulfur Dioxide (SO2) is emitted from combustion of sulfur-containing fuels and from the smelting of sulfur- containing ores. Within the United States, the Mid-Atlantic region receives the highest sulfuric acid and sulfate loadings. This study describes atmospheric SO2 variability and transport pathways in the western Pennsylvania border region. SO2 variability during 2004 was examined at seven EPA ground-based monitoring sites in western Pennsylvania. Atmospheric transport pathways and precipitation patterns along the pathways were examined using NOAA HYSPLIT back trajectories. This study found that high levels of SO2 were associated with areas of high population density. The diurnal SO2 pattern for six out of the seven sites showed that SO2 mixing ratios peaked around 2 pm. However, the northern most site in Erie, PA showed no diurnal cycle. Farrell, PA, centrally located along the state's western border, had the lowest average SO2 levels. Transport pathways were dominated by westerly winds from the Ohio River Valley but also included re- circulation from industrial and urban sites to the east. These observations indicate that regional SO2 concentrations vary considerably over relatively small geographic areas. This suggests that further research on regional pollution must include finer scale examinations of regional circulation patterns.

Snow, J. A.; Fujii, D. C.; Livingston, J.; Batina, M. C.

2006-12-01

261

40 CFR 97.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2012 CFR

...a CAIR SO2 source subject to an Acid Rain emissions limitation, the Administrator...CAIR SO2 source not subject to an Acid Rain emissions limitation, the Administrator...if the source is subject to an Acid Rain emissions limitation, the...

2012-07-01

262

MODELING OF SO2 REMOVAL IN SPRAY-DRYER FLUE-GAS DESULFURIZATION SYSTEM  

EPA Science Inventory

The report presents a comprehensive mathematical model of the SO2 removal process in a spray-dryer flue-gas desulfurization system. Simultaneous evaporation of a sorbent droplet and absorption/reaction of SO2 in the droplet are described by the corresponding heat- and mass-transf...

263

Monitoring so2 emission at the Soufriere Hills volcano: Implications for changes in eruptive conditions  

USGS Publications Warehouse

Correlation spectrometer measurements of sulfur dioxide (SO2) emission rates during the current eruption of the Soufriere Hills volcano, Montserrat, have contributed towards identifying different phases of volcanic activity. SO2 emission rate has increased from 550 td-1 (>6.4 kgs-1) after July 1996, with the uncertainty associated with any individual measurement ca. 30%. Significantly enhanced SO2 emission rates have been identified in association with early phreatic eruptions (800 td-1 (9.3 kgs-1)) and episodes of vigorous dome collapse and pyroclastic flow generation (900 to 1500 td-1 (10.4 to 17.4 kgs-1)). SO2 emission rate has proved a useful proxy measurement for magma production rate. Observed SO2 emission rates are significantly higher than those inferred from analyses of glass inclusions in phenocrysts, implying the existence of a S-rich magmatic vapour phase.

Young, S.R.; Francis, P.W.; Barclay, J.; Casadevall, T.J.; Gardner, C.A.; Darroux, B.; Davies, M.A.; Delmelle, P.; Norton, G.E.; Maciejewski, A.J.H.; Oppenheimer, C.M.M.; Stix, J.; Watson, I.M.

1998-01-01

264

Single photon ionization of van der Waals clusters with a soft x-ray laser: ,,SO2...n and ,,SO2...n,,H2O...m  

E-print Network

that return to earth in the form of acid depositions or "acid rain." Acid rain is one of the biggest environmental problems at present. Sulfur dioxide is the major contributor to acid rain and a generator of soot. The process of SO2 and water form- ing acid rain has been studied for some time in order to determine

Rocca, Jorge J.

265

$\\frac{{\\rm SO}(2N)}{U(N)}$ Riccati-Hartree-Bogoliubov equation based on the SO(2N) Lie algebra of the fermion operators  

NASA Astrophysics Data System (ADS)

In this paper we present the induced representation of SO(2N) canonical transformation group and introduce (SO(2N))/(U(N)) coset variables. We give a derivation of the time-dependent Hartree-Bogoliubov (TDHB) equation on the Kähler coset space (G)/(H) = (SO(2N))/(U(N)) from the Euler-Lagrange equation of motion for the coset variables. The TDHB wave function represents the TD behavior of Bose condensate of fermion pairs. It is a good approximation for the ground state of the fermion system with a pairing interaction, producing the spontaneous Bose condensation. To describe the classical motion on the coset manifold, we start from the local equation of motion. This equation becomes a Riccati-type equation. After giving a simple two-level model and a solution for a coset variable, we can get successfully a general solution of time-dependent Riccati-Hartree-Bogoliubov equation for the coset variables. We obtain the Harish-Chandra decomposition for the SO(2N) matrix based on the nonlinear Möbius transformation together with the geodesic flow on the manifold.

Nishiyama, Seiya; da Providência, João

2015-02-01

266

Decomposition treatment of SO2F2 using packed bed DBD plasma followed by chemical absorption.  

PubMed

The technology of packed bed dielectric barrier discharge (DBD) plasma followed by a chemical absorption has been developed and was found to be an efficient way for decomposition treatment of sulfuryl fluoride (SO2F2) in simulated residual fumigant. The effects of energy density, initial SO2F2 concentration, and residence time on the removal efficiency of SO2F2 for the DBD plasma treatment alone were investigated. It was found that the SO2F2 could be removed completely when initial volume concentration, energy density, and residence time were 0.5%, 33.9 kJ/L, and 5.1 s, respectively. The removal mechanism of SO2F2 in the packed bed DBD reactor was discussed. Based on the detailed analysis of SO2F2 molecular stability and its exhaust products in the DBD plasma reactor, it was concluded that the energetic electrons generated in the packed bed DBD reactor played a key role on the removal of SO2F2, and the major decomposition products of SO2F2 detected were SO2, SiF4, and S (Sulfur). Among these products, SiF4 was formed by the F atom reacted with the filler-quartz glass beads (SiO2) in the packed bed DBD reactor. Aqueous NaOH solution was used as the chemical absorbent for the gaseous products of SO2F2 after plasma pretreatment. It was found that the gaseous products in the plasma exhaust could be absorbed and fixed by the subsequent aqueous NaOH solution. PMID:23772855

Nie, Yong; Zheng, Qifeng; Liang, Xiaojiang; Gu, Dayong; Lu, Meizhen; Min, Min; Ji, Jianbing

2013-07-16

267

SO2 plume height retrieval from direct fitting of GOME-2 backscattered radiance measurements  

NASA Astrophysics Data System (ADS)

The use of satellite measurements for SO2 monitoring has become an important aspect in the support of aviation control. Satellite measurements are sometimes the only information available on SO2 concentrations from volcanic eruption events. The detection of SO2 can furthermore serve as a proxy for the presence of volcanic ash that poses a possible hazard to air traffic. In that respect, knowledge of both the total vertical column amount and the effective altitude of the volcanic SO2 plume is valuable information to air traffic control. The Belgian Institute for Space Aeronomy (BIRA-IASB) hosts the ESA-funded Support to Aviation Control Service (SACS). This system provides Volcanic Ash Advisory Centers (VAACs) worldwide with near real-time SO2 and volcanic ash data, derived from measurements from space. We present results from our algorithm for the simultaneous retrieval of total vertical columns of O3 and SO2 and effective SO2 plume height from GOME-2 backscattered radiance measurements. The algorithm is an extension to the GODFIT direct fitting algorithm, initially developed at BIRA-IASB for the derivation of improved total ozone columns from satellite data. The algorithm uses parameterized vertical SO2 profiles which allow for the derivation of the peak height of the SO2 plume, along with the trace gas total column amounts. To illustrate the applicability of the method, we present three case studies on recent volcanic eruptions: Merapi (2010), Grímsvotn (2011), and Nabro (2011). The derived SO2 plume altitude values are validated with the trajectory model FLEXPART and with aerosol altitude estimations from the CALIOP instrument on-board the NASA A-train CALIPSO platform. We find that the effective plume height can be obtained with a precision as fine as 1 km for moderate and strong volcanic events. Since this is valuable information for air traffic, we aim at incorporating the plume height information in the SACS system.

van Gent, J.; Spurr, R.; Theys, N.; Lerot, C.; Brenot, H.; Van Roozendael, M.

2012-04-01

268

Soot and SO2 contribution to the supersites in the MILAGRO campaign from elevated flares in the Tula Refinery  

NASA Astrophysics Data System (ADS)

This work presents a simulation of the plume trajectory emitted by flaring activities of the Miguel Hidalgo Refinery in Mexico. The flame of a representative sour gas flare is modeled with a CFD combustion code in order to estimate emission rates of combustion by-products of interest for air quality: acetylene, ethylene, nitrogen oxides, carbon monoxide, soot and sulfur dioxide. The emission rates of NO2 and SO2 were compared with measurements obtained at Tula as part of MILAGRO field campaign. The rates of soot, VOCs and CO emissions were compared with estimates obtained by Instituto Mexicano del Petróleo (IMP). The emission rates of these species were further included in WRF-Chem model to simulate the chemical transport of the plume from 22 to 27 March of 2006. The model presents reliable performance of the resolved meteorology, with respect to the Mean Absolute Error (MAE), Root Mean Square Error (RMSE), mean bias (BIAS), vector RMSE and Index of Agreement (IOA). WRF-Chem outputs of SO2 and soot were compared with surface measurements obtained at the three supersites of MILAGRO campaign. The results suggest a contribution of Tula flaring activities to the total SO2 levels of 18% to 27% at the urban supersite (T0), and of 10% to 18% at the suburban supersite (T1). For soot, the model predicts low contribution at the three supersites, with less than 0.1% at three supersites. According to the model, the greatest contribution of both pollutants to the three supersites occurred on 23 March, which coincides with the third cold surge event reported during the campaign.

Almanza, V. H.; Molina, L. T.; Sosa, G.

2012-11-01

269

Soot and SO2 contribution to the supersites in the MILAGRO campaign from elevated flares in the Tula Refinery  

NASA Astrophysics Data System (ADS)

This work presents a simulation of the plume emitted by flaring activities of the Miguel Hidalgo Refinery in Mexico. The flame of a representative sour gas flare is modeled with a CFD combustion code in order to estimate emission rates of combustion by-products of interest for air-quality: acetylene, ethylene, nitrogen oxides, carbon monoxide, soot and sulfur dioxide. The emission rates of NO2 and SO2 were compared against measurements obtained at Tula as part of MILAGRO field campaign. The rates of soot, VOCs and CO were compared with estimates obtained by IMP. The emission rates of the species considered were further included in WRF-Chem model to simulate the chemical transport of the plume from 22 March to 27 March of 2006. The model presents reliable performance of the resolved meteorology, with respect to the Mean Absolute Error (MAE), Root Mean Square Error (RMSE), vector RMSE and Index of Agreement (IOA). WRF-Chem outputs of SO2 and soot were compared with surface measurements obtained at the three supersites of MILAGRO campaign. The results suggest a contribution of Tula flaring activities to the total SO2 levels of 23% to 37% at the urban supersite (T0), and of 29% to 39% at the suburban supersite (T1). For soot, the model predicts low contribution at the three supersites, with less than 1% at both T0 and T1; and about 1% at T2. According to the model, the greatest contribution of both pollutants to the three supersites occurred on 23 March, which coincides with the third cold surge event.

Almanza, V. H.; Molina, L. T.; Sosa, G.

2012-06-01

270

Regional differences in Chinese SO2 emission control efficiency and policy implications  

NASA Astrophysics Data System (ADS)

SO2 emission control has been one of the most important air pollution policies in China since 2000. In this study, we assess regional differences in SO2 emission control efficiencies in China through the modeling analysis of four scenarios of SO2 emissions, all of which aim at reducing the national total SO2 emissions by 8% or 2.3 Tg below the 2010 emissions level, the target set by the current 12th FYP (2011-2015), but differ in the spatial implementation. The GEOS-Chem chemical transport model is used to evaluate the efficiency of each scenario on the basis of three impact metrics: surface sulfate concentration, population-weighted sulfate concentration (PWC), and sulfur export flux from China to the Western Pacific. The efficiency of SO2 control (?) is defined as the relative change of each impact metric to a 1% reduction of SO2 emissions from the 2010 baseline. The S1 scenario, which adopts a spatially uniform reduction of SO2 emissions in China, gives a ? of 0.71, 0.83, and 0.67 for sulfate concentration, PWC, and export flux, respectively. By comparison, the S2 scenario, which implements all the SO2 emissions reduction over North China (NC), is found most effective in reducing national-mean surface sulfate concentrations and sulfur export fluxes, with ? being 0.76 and 0.95 respectively. The S3 scenario of implementing all the SO2 emission reduction over South China (SC) has the highest ? in reducing PWC (? = 0.98) because SC has the highest correlation between population density and sulfate concentration. Reducing SO2 emissions over Southwest China (SWC) is found to be least efficient on the national scale, albeit within-region benefit. The difference in ? by scenario is attributable to regional differences in SO2 oxidation pathways and source-receptor relationships. Among the three regions examined here, NC shows the largest proportion of sulfate formation from gas phase oxidation, which is more sensitive to SO2 emission change than aqueous oxidation. In addition, NC makes the largest contribution to inter-regional transport of sulfur within China and to the transport fluxes to Western Pacific. The policy implication is that China needs to carefully design a regionally specific implementation plan of realizing its SO2 emissions reduction target in order to maximize the resulting air quality benefits not only for China but for the downwind regions, with emphasis on reducing emissions from NC.

Zhang, Q. Q.; Wang, Y.; Ma, Q.; Xie, Y.; He, K.

2015-02-01

271

Combining Bayesian methods and aircraft observations to constrain the HO. + NO2 reaction rate  

Microsoft Academic Search

Tropospheric ozone is the third strongest greenhouse gas, and has the highest uncertainty in radiative forcing of the top five greenhouse gases. Throughout the troposphere, ozone is produced by radical oxidation of nitrogen oxides (NOx = NO + NO2). In the upper troposphere (8-10 km), current chemical transport models under-estimate nitrogen dioxide (NO2) observations. Improvements to simulated NOx emissions from

B. H. Henderson; R. W. Pinder; J. Crooks; R. C. Cohen; A. G. Carlton; H. O. T. Pye; W. Vizuete

2011-01-01

272

Hydrogen Peroxide Enhances Removal of NOx from Flue Gases  

NASA Technical Reports Server (NTRS)

Pilot scale experiments have demonstrated a method of reducing the amounts of oxides of nitrogen (NOx) emitted by industrial boilers and powerplant combustors that involves (1) injection of H2O2 into flue gases and (2) treatment of the flue gases by caustic wet scrubbing like that commonly used to remove SO2 from combustion flue gases. Heretofore, the method most commonly used for removing NOx from flue gases has been selective catalytic reduction (SCR), in which the costs of both installation and operation are very high. After further development, the present method may prove to be an economically attractive alternative to SCR.

Collins, Michelle M.

2005-01-01

273

Comparison of COSPEC and two miniature ultraviolet spectrometer systems for SO2 measurements using scattered sunlight  

USGS Publications Warehouse

The correlation spectrometer (COSPEC), the principal tool for remote measurements of volcanic SO2, is rapidly being replaced by low-cost, miniature, ultraviolet (UV) spectrometers. We compared two of these new systems with a COSPEC by measuring SO2 column amounts at Ki??lauea Volcano, Hawaii. The two systems, one calibrated using in-situ SO2 cells, and the other using a calibrated laboratory reference spectrum, employ similar spectrometer hardware, but different foreoptics and spectral retrieval algorithms. Accuracy, signal-to-noise, retrieval parameters, and precision were investigated for the two configurations of new miniature spectrometer. Measurements included traverses beneath the plumes from the summit and east rift zone of Ki??lauea, and testing with calibration cells of known SO2 concentration. The results obtained from the different methods were consistent with each other, with <8% difference in estimated SO2 column amounts up to 800 ppm m. A further comparison between the COSPEC and one of the miniature spectrometer configurations, the 'FLYSPEC', spans an eight month period and showed agreement of measured emission rates to within 10% for SO2 column amounts up to 1,600 ppm m. The topic of measuring high SO2 burdens accurately is addressed for the Ki??lauea measurements. In comparing the foreoptics, retrieval methods, and resultant implications for data quality, we aim to consolidate the various experiences to date, and improve the application and development of miniature spectrometer systems. ?? Springer-Verlag 2006.

Elias, T.; Sutton, A.J.; Oppenheimer, C.; Horton, K.A.; Garbeil, H.; Tsanev, V.; McGonigle, A.J.S.; Williams-Jones, G.

2006-01-01

274

Adsorption of SO2 onto oxidized and heat-treated activated carbon fibers (ACFS)  

USGS Publications Warehouse

A series of activated carbon fibers (ACFs) and heat-treated oxidized ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore surface chemistry and pore volume for the adsorption of SO2 and its catalytic conversion to H2SO4. For untreated ACFs, the initial rate of SO2 adsorption from flue gas was shown to be inversely related to pore size. At longer times, the amount of SO2 adsorbed from flue gas was dependent on both the pore size and pore volume. Oxidation of the ACFs, using an aqueous oxidant, decreased their adsorption capacity for SO2 from flue gas due to a decrease in pore volume and repulsion of the SO2 from acidic surface groups. If these samples were heat-treated to desorb the oxygen containing function groups, the amount of SO2 adsorption increased. This increase in adsorption capacity was directly correlated to the amount of CO2 evolved during heat-treatment of the oxidized ACFs. The amount of SO2 adsorbed for these samples was related to the pore size, pore surface chemistry and pore volume. This analysis is explained in more detail in this paper. ?? 1997 Elsevier Science Ltd. All rights reserved.

Daley, M.A.; Mangun, C.L.; DeBarr, J.A.; Riha, S.; Lizzio, A.A.; Donnals, G.L.; Economy, J.

1997-01-01

275

Gas-phase ion chemistry of NF3/SO2 mixtures  

NASA Astrophysics Data System (ADS)

The gas-phase ion chemistry of NF3/SO2 mixtures has been investigated by ion trap mass spectrometry and theoretical calculations. SO+ and SO2+ react efficiently with NF3 giving F(SO)+ and F(SO2)+. CAD experiments and thermochemical considerations support the exclusive formation of the sulfur-fluorine cations FSO+ and FSO2+. NF2+ is unreactive toward SO2, and NF3+ undergoes exclusively the efficient charge transfer. On the other hand, NF+ activates the OSO bond, with formation of SO+ and NO+. DFT and coupled cluster calculations indicate that these ionic products arise from a SO+-(FNO) ion-dipole complex, which dissociates into SO+ and FNO or NO+ and FSO. This intermediate is more stable than NF+ and SO2 by nearly 60 kcal mol-1. We have also located a less stable sulfur-nitrogen complex FNSO2+, whose formation explains the less efficient observed charge transfer between NF+ and SO2. The only observed negative ion-molecule reaction is the formation of FSO2- from the reaction between SO2- and NF3. Our investigated processes may be of interest for the plasma and the atmospheric chemistry of NF3, one of the gaseous compounds most extensively used in the electronic industry to perform etching and cleaning processes.

Antoniotti, Paola; Rabezzana, Roberto; Turco, Francesca; Borocci, Stefano; Bronzolino, Nicoletta; Grandinetti, Felice

2007-10-01

276

Simultaneous adsorption of SO2 and NO from flue gas over mesoporous alumina.  

PubMed

Mesoporous alumina (MA) with a higher ability to simultaneously remove SO2 and NO was prepared by the evaporation-induced self-assembly process. The adsorption capacities of MA are 1.79 and 0.702?mmol/g for SO2 and NO, respectively. The Brunauer-Emmett-Teller method was used to characterize the adsorbent. Simultaneous adsorption of SO2 and NO from flue gas over MA in different operating conditions had been studied in a fixed bed reactor. The effects of temperature, oxygen concentration and water vapour were investigated. The experimental results showed that the optimum temperature for MA to simultaneously remove SO2 and NO was 90°C. The simultaneous adsorption capacities of SO2 and NO could be enhanced by increasing O2 when its concentration was below 5%. The changes of simultaneous adsorption capacities were not obvious when O2 concentration was above 5%. The increase in relative humidity results in an increase after dropping of SO2 adsorption capacity, whereas the adsorption capacity of NO showed an opposite trend. The results suggest that MA is a great adsorbent for simultaneous removal of SO2 and NO from flue gas. PMID:25189414

Sun, Xin; Tang, Xiaolong; Yi, Honghong; Li, Kai; Ning, Ping; Huang, Bin; Wang, Fang; Yuan, Qin

2015-03-01

277

[Domestication study about desulfuration microorganism from oxidation ditch by low concentration SO2].  

PubMed

An excellent desulfuration microorganism with a quick growth and propagation, high activation, high efficiency of removing SO2 is obtained from oxidation ditch of a city sewage treatment plant by inductive acclimatization over 6 d with low concentration SO2 gas (100-2 000 mg/m3). The desulfurition microorganism get their energy sources for growth from transforming SO2 (SO3(2-)) to SO4(2-). The predominant bacterium of the desulfuration microorganism has the same characteristic with Thiobacillus ferrooxidans (T. ferrooxidans), which showed that it was Gram negative, short rod bacteria with a single polar flagellum under a microscopic examination, and obtained its nourishment through the oxidation of inorganic compounds. The technology process condition of domestication and desulfuration of microorganism are particular studied, and the results showed that aerating time, SO2 flux and time to provide nutriment contained N, P, K to microorganism were very important. They have an ability with degradation rate of 160g/ (m3 x h) and degradation efficiency over 50% to transform sulfite to sulfate in liquid phase. The bacteria have a 98% of removing efficiency and over 80% of biodegradation efficiency for the 5 500 mg/m3 SO2 gas and the outlet concentration of SO2 is lower than 100 mg/m3, and also have a 95% of removing efficiency for 15 000 mg/m3 SO2 gas in the packed tower reactor with Raschig ring at 3s contact time. PMID:20698284

Huang, Bing; Shi, Zhe; Wang, Yan-Yan; Zhang, Shi-Ling

2010-06-01

278

Measurements of dimethyl sulfide and SO2 during GTE/CITE 3  

NASA Technical Reports Server (NTRS)

As part of NASA's Tropospheric Experiment Chemical Instrumentation Test and Evaluation (GTE/CITE 3) Sulfur Gas Intercomparison, we conducted measurements of dimethyl sulfide (DMS) and SO2 using two techniques well suited for sampling from an aircraft due to their simplicity of design. DMS was collected by preconcentration on gold wire preceded by a KOH-impregnated filter oxidant scrubber, and analyzed by gas chromatography with flame photometric detection. SO2 was collected on K2CO3/glycerol-impregnated filters and analyzed by ion chromatography. In blind tests, both techniques produced excellent agreement with National Institutes of Standards and Technology (NIST) standards. For field measurements, the DMS technique produced excellent correlation with the mean of the six different techniques intercompared. For SO2, the five techniques intercompared were rather poorly correlated, but correlations between the three techniques which passed NIST standards tests were somewhat better. Our SO2 filter measurements exhibited rather large uncertainties due to higher than normal variabiltiy of the filter blanks, which we believe was caused by extended storage in the field. In measurements conducted off the coast of Natal, Brazil, a diurnal afternoon minimum in DMS concentrations accompanied by a corresponding maximum in SO2 concentrations was observed. However, due to rather large uncertainties in the SO2 measurements, any conclusions about the SO2 trend must by considered tentative.

Ferek, Ronald J.; Hegg, Dean A.

1993-01-01

279

Lessons Learned from OMI Observations of Point Source SO2 Pollution  

NASA Technical Reports Server (NTRS)

The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. Although anthropogenic SO2 signals may not be detectable in a single OMI pixel, it is possible to see the source and determine its exact location by averaging a large number of individual measurements. We describe new techniques for spatial and temporal averaging that have been applied to the OMI SO2 data to determine the spatial distributions or "fingerprints" of SO2 burdens from top 100 pollution sources in North America. The technique requires averaging of several years of OMI daily measurements to observe SO2 pollution from typical anthropogenic sources. We found that the largest point sources of SO2 in the U.S. produce elevated SO2 values over a relatively small area - within 20-30 km radius. Therefore, one needs higher than OMI spatial resolution to monitor typical SO2 sources. TROPOMI instrument on the ESA Sentinel 5 precursor mission will have improved ground resolution (approximately 7 km at nadir), but is limited to once a day measurement. A pointable geostationary UVB spectrometer with variable spatial resolution and flexible sampling frequency could potentially achieve the goal of daily monitoring of SO2 point sources and resolve downwind plumes. This concept of taking the measurements at high frequency to enhance weak signals needs to be demonstrated with a GEOCAPE precursor mission before 2020, which will help formulating GEOCAPE measurement requirements.

Krotkov, N.; Fioletov, V.; McLinden, Chris

2011-01-01

280

Evaluation of tropospheric SO2 retrieved from MAX-DOAS measurements in Xianghe, China  

NASA Astrophysics Data System (ADS)

Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of sulfur dioxide (SO2) have been performed at the Xianghe station (39.8° N, 117.0° E) located at ~ 50 km southeast of Beijing from March 2010 to February 2013. Tropospheric SO2 vertical profiles and corresponding vertical column densities (VCDs), retrieved by applying the optimal estimation method to the MAX-DOAS observations, have been used to study the seasonal and diurnal cycles of SO2, in combination with correlative measurements from in situ instruments, as well as meteorological data. A marked seasonality was observed in both SO2 VCD and surface concentration, with a maximum in winter (February) and a minimum in summer (July). This can be explained by the larger emissions in winter due to the domestic heating and, in case of surface concentration, by more favorable meteorological conditions for the accumulation of SO2 close to the ground during this period. Wind speed and direction are also found to be two key factors in controlling the level of the SO2-related pollution at Xianghe. In the case of east or southwest wind, the SO2 concentration does not change significantly with the wind speed, since the city of Tangshan and heavy polluting industries are located to the east and southwest of the station, respectively. In contrast, when wind comes from other directions, the stronger the wind, the less SO2 is observed due to a more effective dispersion. Regarding the diurnal cycle, the SO2 amount is larger in the early morning and late evening and lower at noon, in line with the diurnal variation of pollutant emissions and atmospheric stability. A strong correlation with correlation coefficients between 0.6 and 0.9 is also found between SO2 and aerosols in winter, suggesting that anthropogenic SO2, through the formation of sulfate aerosols, contributes significantly to the total aerosol content during this season. The observed diurnal cycles of MAX-DOAS SO2 surface concentration are also in very good agreement (correlation coefficient close to 0.9) with those from collocated in situ data, indicating the good reliability and robustness of our retrieval.

Wang, T.; Hendrick, F.; Wang, P.; Tang, G.; Clémer, K.; Yu, H.; Fayt, C.; Hermans, C.; Gielen, C.; Müller, J.-F.; Pinardi, G.; Theys, N.; Brenot, H.; Van Roozendael, M.

2014-10-01

281

Cl2SO_2 deposits near the Marduk's volcanic center on Io  

NASA Astrophysics Data System (ADS)

An absorption feature at 3.92 ? m locally present in NIMS data near Marduk's volcanic center on Io has been tentatively identified by Cl2SO_2 or possibly H2S (Schmitt and Rodriguez 2000: BAAS, 32, 1048). Direct comparison between laboratory spectra and the Marduk NIMS spectrum, coupled with radiative transfer modeling, allows to propose as the surface material producing the 3.92 ? m absorption either: - a (sub-)micron thin layer of pure solid H2S (phase II), (compact or sub-micron particles), at T > 103.6 K condensed on top of SO2 ice or, - a millimeter thick layer of 1% Cl2SO_2 mixed with solid SO2 covering a similar mixture strongly depleted in Cl2SO_2 (< 0.1%). Spectral constraints on the 3.92 ? m band alone, though favoring Cl2SO_2 (better fit), are not able to unambiguously distinguish between these two possible identifications. Unfortunately, both molecules did not possess other bands strong enough to clearly appear in the NIMS data and firmly confirm one of these candidates. On the chemical point of view the volcanic model of Fegley and Zolotov (2000) needs particular physical conditions in the vent to produce more than 10-5 mole fraction of Cl2SO_2, an amount still not enough to account for the intensity of the band. On the other hand, it may produce enough H2S but our spectral modeling set an upper limit of 0.04 for the H2O / H2S abundance ratio in contradiction with the predicted value (about 10). The sublimation rates of Cl2SO_2 and SO2 have been measured in the laboratory at low temperature. We found that the relative volatilities of H2S, Cl2SO_2 and SO2 coupled with their inferred physical states and the surface temperature conditions of Io strongly favor the incorporation of the chlorine molecule in solid SO2 at a concentration about 4 orders of magnitude larger than in the gas. On the other hand, the formation of a thin layer of pure solid H2S seems very improbable, or at least extremely ephemeral at the surface of Io. We conclude on some possible implications on Io's chemistry. We acknowledge CNES and the French Programme National de Planétologie of CNRS (INSU) for their financial supports.

Schmitt, B.; Rodriguez, S.; NIMS/Galileo Team

2001-11-01

282

Effect of SO(2) and O(3) on Production of Antioxidants in Conifers.  

PubMed

Production of antioxidants was investigated in needles of fir (Abies alba Mill.) and spruce (Picea abies (L.) Karst) after exposure to low concentrations of SO(2), O(3), and a combination of both pollutants. Glutathione reacted most sensitively to pollutants followed by vitamin E and vitamin C. In spruce needles, the overall increase of antioxidants after exposure to air pollutants was lower than in needles of fir. SO(2) was more potent than O(3). Maximum increase of antioxidants was found in needles after exposure of trees to SO(2) + O(3). PMID:16665019

Mehlhorn, H; Seufert, G; Schmidt, A; Kunert, K J

1986-09-01

283

Measurements of SO2 concentration and atmospheric structure in Delta and Breton wildlife refuges  

SciTech Connect

A field program designed to measure the ambient concentrations of SO2 as well as pertinent meteorological parameters was conducted during the summer of 1993. Three stations were established in the EPA Class 1 areas of Breton and Delta Wildlife Refuges near the mouth of the Mississippi River. It was found that the SO2 concentration measured throughout the monitoring duration was only 2% of the National maximum allowable once per year. The passage of a weak cold front in September showed that the SO2 concentrations were higher when the wind blew from land to the Gulf than under normal summer conditions when the wind blew from the Gulf toward land.

Hsu, S.A.

1995-04-01

284

Validation of satellite SO2 observations in northern Finland during the Icelandic Holuhraun fissure eruption  

NASA Astrophysics Data System (ADS)

This paper shows the validation results of the satellite SO2 observations from OMI (Ozone Monitoring Instrument) and OMPS (Ozone Mapping Profiler Suite) during the Icelandic Holuhraun fissure eruption in September 2014. The volcanic plume reached Finland on several days during the month of September. The SO2 total columns from the Brewer direct sun (DS) measurements in Sodankylä (67.42° N, 26.59° E), northern Finland, are compared to the satellite data. Challenging retrieval conditions at high latitudes (like large solar zenith angle, SZA) are considered in the comparison. The results show that the best agreement can be found for small SZAs, close-to-nadir satellite pixels, cloud fraction below 0.3 and small distance between the station and the centre of the pixel. Under good retrieval conditions, the difference between satellite data and Brewer measurements remains mostly below the uncertainty on the satellite SO2 retrievals (up to about 2 DU at high latitudes). The satellite products assuming a priori profile with SO2 predominantly in the planetary boundary layer give total column values close to the ground-based data, suggesting that the volcanic SO2 plume was located at particularly low altitudes. This is connected to the fact that this was a fissure eruption and most of the SO2 was emitted into the troposphere. The analysis of the SO2 surface concentrations at four air quality stations in northern Finland supports the hypothesis that the volcanic plume coming from Iceland was located very close to the surface. The time evolution of the SO2 concentrations peaks during the same days when large SO2 total column values are measured by the Brewer in Sodankylä and enhanced SO2 signal is visible over northern Finland from the satellite maps. This is an exceptional case because the SO2 volcanic emission directly affect the air quality levels at surface in an otherwise pristine environment like northern Finland. OMI and OMPS SO2 retrievals from direct-broadcast measurements are validated for the first time in this paper.

Ialongo, I.; Hakkarainen, J.; Kivi, R.; Anttila, P.; Krotkov, N. A.; Yang, K.; Li, C.; Tukiainen, S.; Hassinen, S.; Tamminen, J.

2015-01-01

285

Economics of an integrated approach to control SO2, NOX, HCl, and particulate emissions from power plants.  

PubMed

An integrated approach for the simultaneous reduction of major combustion-generated pollutants from power plants is presented along with a simplified economic analysis. With this technology, the synergistic effects of high-temperature sorbent/coal or sorbent/natural gas injection and high-temperature flue gas filtration are exploited. Calcium-based (or Na-based, etc.) sorbents are sprayed in the post-flame zone of a furnace, where they react with S- and Cl-containing gases to form stable salts of Ca (or Na, etc.). The partially reacted sorbent is then collected in a high-temperature ceramic filter, which is placed downstream of the sorbent injection point, where it further reacts for a prolonged period of time. With this technique, both the likelihood of contact and the length of time of contact between the solid sorbent particles and the gaseous pollutants increase, because reaction takes place both in the furnace upstream of the filter and inside the filter itself. Hence, the sorbent utilization increases significantly. Several pollutants, such as SO2, H2S, HCl, and particulate (soot, ash, and tar), may be partially removed from the effluent. The organic content of the sorbents (or blends) also pyrolyzes and reduces NOx. Unburned carbon in the ash may be completely oxidized in the filter. The filter is cleaned periodically with aerodynamic regeneration (back pulsing) without interrupting furnace operation. The effectiveness of this technique has been shown in laboratory-scale experiments using either rather costly carboxylic salts of Ca or low- to moderate-cost blends of limestone, lime, or sodium bicarbonate with coal fines. Injection occurred in the furnace at 1150 degrees C, while the filter was maintained at 600 degrees C. Results showed that 65 or 40% SO2 removal was obtained with calcium formate or a limestone/coal blend, respectively, at an entering calcium-to-sulfur molar ratio of 2. A sodium bicarbonate/coal blend resulted in 78% SO2 removal at a sodium-to-sulfur molar ratio of 2. HCl removal efficiencies have been shown to be higher than those for SO2. NOx reductions of 40% have been observed with a fuel (coal)-to-air equivalence ratio, phi, around 2. The filter has been shown to be 97-99% efficient in removing PM2.5 particulates. Calculations herein show that this integrated sorbent/filter method is cost-effective, in comparison with current technologies, on both capital cost ($/kW) and levelized cost ($/ton pollutant removed) bases, if a limestone/coal mixture is used as the sorbent for fossil fuel plants. Capital costs for the filter/sorbent combination are estimated to be in the range of $61-$105/kW for a new plant. Because current technologies are designed for removing one pollutant at a time, both their cost and space requirements are higher than those of this integrated technique. At the minimum projected removal efficiencies for HCl/SO2/NOx of about 40%, the levelized costs are projected to be $203-$261/ton of combined pollutant SO2/HCl/NOx and particulates removed from coal-fired power plants. PMID:12022692

Shemwell, Brooke E; Ergut, Ali; Levendis, Yiannis A

2002-05-01

286

Interaction of Al2O3 and CeO2 surfaces with SO2 and SO2 + O2 studied by X-ray photoelectron spectroscopy.  

PubMed

The interaction of Al2O3 and CeO2 thin films with sulfur dioxide (2.5 mbar) or with mixtures of SO2 with O2 (5 mbar) at various temperatures (30-400 degrees C) was studied by X-ray photoelectron spectroscopy (XPS). The analysis of temperature-induced transformations of S2p spectra allowed us to identify sulfite and sulfate species and determine the conditions of their formation on the oxide surfaces. Sulfite ions, SO3(2-), which are characterized by the S2p(3/2) binding energy (BE) of approximately 167.5 eV, were shown to be formed during the interaction of the oxide films with pure SO2 at temperatures < or =200 degrees C, whereas sulfate ions, SO4(2-), with BE (S2p(3/2)) approximately 169 eV were produced at temperatures > or =300 degrees C. The formation of both the sulfite and sulfate species proceeds more efficiently in the case of CeO2. The addition of oxygen to SO2 suppresses the formation of the sulfite species on both oxides and facilitates the formation of the sulfate species. Again, this enhancement is more significant for the CeO2 film than for the Al2O3 one. The sulfation of the CeO2 film is accompanied by a reduction of Ce(IV) ions to Ce(III) ones, both in the absence and in the presence of oxygen. It has been concluded that the amount of the sulfates on the CeO2 surface treated with the SO2 + O2 mixture at > or =300 degrees C corresponds to the formation of a 3D phase of the Ce(III) sulfate. The sulfation of Al2O3 is limited by the surface of the oxide film. PMID:16852438

Smirnov, Mikhail Yu; Kalinkin, Alexander V; Pashis, Andrei V; Sorokin, Alexei M; Noskov, Alexander S; Kharas, Karl C; Bukhtiyarov, Valerii I

2005-06-16

287

Solids Liquids and Gases  

NSDL National Science Digital Library

Compare and contrast the three states of matter: solids, liquids and gases. First you will begin by looking at characteristics of each solids, liquids and gasesGases, Liquids and Solids Facts. Then you will look at examples of each stateSolids, Liquids and Gases Video. Demonstrate an understanding of solids, liquids and gases by playing interactive gameSolids, Liquids and Gases Game. Graphic Organizer is here to be filled out as you learn during this lesson. Use the red ...

Ms. Salter

2009-10-22

288

Quantum cascade laser sensor for SO2 and SO3 for application to combustor exhaust streams.  

PubMed

We have demonstrated a high-sensitivity, room-temperature quantum-cascade (QC) laser sensor for detection of SO2 and SO3 under conditions relevant to aircraft test combustor exhaust. Two QC lasers probe infrared absorption features at 7.50 and 7.16 microm for SO2 and SO3, respectively, with a common dual-beam detection system. We inferred a noise-equivalent absorbance of approximately 1 x 10(-4) Hz(-1/2). We have demonstrated detection limits for both SO2 and SO3 of 1-2 ppmv m/Hz(1/2) (where ppmv is parts in 10(6) by volume) for 300 torr, elevated temperature, and path lengths near 1 m. This level of sensitivity permits measurement of < 1 ppmv of SO2 and SO3 at these conditions with modest signal averaging. PMID:16270552

Rawlins, Wilson T; Hensley, Joel M; Sonnenfroh, David M; Oakes, David B; Allen, Mark G

2005-11-01

289

The SO2 Allowance Trading System: The Ironic History of a Grand Policy Experiment  

E-print Network

Two decades have passed Two decades have passed since the Clean Air Act Amendments of 1990 launched a grand experiment in market-based environmental policy: the SO2 cap-and-trade system. That system performed well but ...

Schmalensee, Richard

290

Climate Co-benefits of Tighter SO2 and NOx Regulations in China  

E-print Network

Air pollution has been recognized as a significant problem in China. In its Twelfth Five Year Plan (FYP), China proposes to reduce SO2 and NOx emissions significantly, and here we investigate the cost of achieving those ...

Nam, Kyung-Min

2012-10-01

291

DETECTION OF SO2 AT HIGH TEMPERATURE WITH ELECTRICALLY BIASED, SOLID-ELECTROLYTE SENSING ELEMENTS  

SciTech Connect

Design and operation of sensing elements for the detection of sulfur dioxide (SO2) at high temperature (800 900 oC) is described. The sensing elements consisted of three (two oxide and one Pt) electrodes on yttria-stabilized zirconia substrates. To operate the elements, a constant current (usually on the order of 0.1 mA) was driven between two of the electrodes and the voltage between one of these electrodes and the third electrode was monitored and used as the sensing signal. In one example, 31 ppm SO2 caused an approximately 40% change in the element output, and 2 ppm of SO2 could be easily detected. The cross-sensitivity to several interferents such as NOx was evaluated and found to be relatively small in comparison to the SO2 response.

West, David L [ORNL; Montgomery, Fred C [ORNL; Armstrong, Timothy R. [ORNL

2008-01-01

292

Why are allowance prices so low? : an analysis of the SO2 emissions trading program  

E-print Network

This paper presents an analysis of the reduction in SO2 emissions by electric utilities between 1985 and 1993. We find that emissions have been reduced for reasons largely unrelated to the emission reduction mandate ...

Ellerman, A. Denny

1996-01-01

293

Effect of SO2 concentration on polyphenol development during red wine micro-oxygenation.  

PubMed

A Merlot wine in 15 L research tanks was subjected to micro-oxygenation at 10 mL O2 per liter of wine per month over a 16 week period with additions of 0, 50, 100, and 200 mg/L SO2. A large decrease in monomeric anthocyanins and flavan-3-ols was seen in wines with a lower concentration of SO2, coupled with an increase in nonbleachable pigments; an increase in tannin, measured using precipitation with methyl cellulose; and a greater size and red coloration of a proanthocyanidin extract obtained using Sephadex LH-20. These changes were largely suppressed in wines initially treated with 200 mg/L SO2 and occurred more slowly in wines stored in bottles in the absence of O2. The concentration of SO2 is shown to regulate the polyphenol chemistry involved in the formation of polymeric pigments and changes in tannin structure affecting wine astringency. PMID:17602651

Tao, Jianxiong; Dykes, Stuart I; Kilmartin, Paul A

2007-07-25

294

FACTORS AFFECTING DRY DEPOSITION OF SO2 ON FORESTS AND GRASSLANDS  

EPA Science Inventory

Deposition velocities for SO2 over forests and grasslands are derived through a mass conservation approach using established empirical relations descriptive of the atmospheric transport of a gaseous contaminant above and within a vegetational canopy. Of particular interest are si...

295

[Level and stability of resistance to SO2 in wild strain of Saccharomyces ellipsoideus (author's transl)].  

PubMed

We have determined the level and the stability of the resistance of SO2 of yeast strains isolated in highly sulfitated musts. The resistance to antiseptic decreases during the storage and successive transfers of strains. PMID:1243963

Romano, P; Tini, V

1975-01-01

296

Photochemistry of SO2 in the atmosphere of Io and implications on atmospheric escape  

NASA Technical Reports Server (NTRS)

Photochemical models of Io's atmosphere are presented with the assumption that SO2 is the major gas and that the SO2 surface pressure is controlled by vapor-pressure equilibrium at the surface. Photolysis of SO2 leads to efficient production of SO, O2, S, and O. Of these products, O and S are likely to be the dominant constituents in the upper atmosphere, and the atmospheric escape is expected to be in atomic form. Nonthermal escape processes are necessary to populate the plasma torus. SO2 surface densities greater than 100-billion per cu cm are needed on the dayside to supply the required amounts of S and O to maintain the torus. Surface chemistry presents an interesting possibility, namely, the conversion of O to O2, in which case O2 will be the dominant constituent throughout the nightside and over the polar caps with a surface O2 density of 10-billion per cu cm.

Kumar, S.

1982-01-01

297

40 CFR 60.42c - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2011 CFR

...neither: cause to be discharged into the atmosphere from the affected facility any gases...nor cause to be discharged into the atmosphere from the affected facility any gases...neither: cause to be discharged into the atmosphere from the affected facility any...

2011-07-01

298

40 CFR 60.42c - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2013 CFR

...neither: cause to be discharged into the atmosphere from the affected facility any gases...nor cause to be discharged into the atmosphere from the affected facility any gases...neither: cause to be discharged into the atmosphere from the affected facility any...

2013-07-01

299

40 CFR 60.42c - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2010 CFR

...neither: cause to be discharged into the atmosphere from the affected facility any gases...nor cause to be discharged into the atmosphere from the affected facility any gases...neither: cause to be discharged into the atmosphere from the affected facility any...

2010-07-01

300

SO2 sequestration in large volcanic eruptions: High-temperature scavenging by tephra  

NASA Astrophysics Data System (ADS)

It is well accepted that the climate impact of large explosive volcanic eruptions results from reduction of solar radiation following atmospheric conversion of magmatic SO2 emissions into H2SO4 aerosols. Thus, understanding the fate of SO2 in the eruption plume is crucial for better assessing volcanic forcing of climate. Here we focus on the potential of tephra to interact with and remove SO2 gas from the eruptive plume. Scavenging of SO2 by tephra is generally assumed to be driven by in-plume, low-temperature reactions between H2SO4 condensates and tephra particles. However, the importance of SO2 gas-tephra interaction above the dew point temperature of H2SO4 (190-200 °C) has never been constrained. Here we report the results of an experimental study where silicate glasses with representative volcanic compositions were exposed to SO2 in the temperature range 25-800 °C. We show that above 600 °C, the uptake of SO2 on glass exhibits optimal efficiency and emplaces surficial CaSO4 deposits. This reaction is sustained via Ca2+ diffusion from the bulk to the surface of the glass particles. At 800 °C, the diffusion coefficient for Ca2+ in the glasses was in the range 10-13-10-14 cm2 s-1. We suggest that high temperature SO2 scavenging by glass-rich tephra proceeds by the same Ca2+ diffusion-driven mechanism. Using a simple mathematical model, we estimated SO2 scavenging efficiencies at 800 °C varying from <1% to 73%, depending mainly on exposure time and tephra matrix glass Ca2+ content. Our results imply that large explosive eruptions with a deep magma fragmentation depth are likely to be affected by significant gas-tephra interaction at temperature above 600 °C. This SO2 sequestration mechanism should be considered when constraining volcanic S budgets, and when coupling the initial magmatic SO2 content and the induced climatic response in some of the Earth's largest eruptions.

Ayris, P. M.; Lee, A. F.; Wilson, K.; Kueppers, U.; Dingwell, D. B.; Delmelle, P.

2013-06-01

301

NO2 GAS SENSING STUDIES : IMPACT OF GEOMETRICAL AND PHYSICAL CHARACTERISTICS OF OHMIC CONTACTS ON n-InP EPITAXIAL SENSITIVE  

E-print Network

steps on electrical and metrological parameters of NO2 gas sensors. The NO2 gas sensors are based of the devices. The impact on the gas sensors in response to NO2 is also discussed. Keywords gas sensor, In for environmental protection. In recent years, the concentration of NOx gases (NO and NO2) in atmosphere has

Paris-Sud XI, Université de

302

CO2 and SO2 activation by a Cr-Cr quintuple bond.  

PubMed

A quintuply bonded dichromium complex stabilized by aminopyridinato ligands activates CO2 and SO2 by reducing the (formal) bond order of the metal-metal bonds. Oxygen abstraction is observed during CO2 activation. SO2 activation proceeds via formation of a unique dithionite complex/coordination. Furthermore, N2O activation was investigated and the formation of a tetrameric Cr-oxo complex was observed. PMID:25225656

Noor, Awal; Qayyum, Sadaf; Bauer, Tobias; Schwarz, Stefan; Weber, Birgit; Kempe, Rhett

2014-11-01

303

SO2 in the Fall in the Arctic: Source Identification Using Sulfur Isotopes  

NASA Astrophysics Data System (ADS)

The Arctic atmosphere, although far from industrial sources, has a large anthropogenic SO2 load. Sulfur dioxide can have other sources including from dimethylsulphide (DMS) oxidation. One way to distinguish between these two types of SO2 is through sulfur isotope apportionment. During the Fall seasons of 2007 and 2008 aerosol sulfate and SO2 were measured at two sites in the Arctic. One site was on board the Canadian Coast Guard Ship, The Amundsen, as it traveled throughout the Arctic and the other site was at Alert, Nunavut, Canada. Sulfur dioxide concentrations at Alert varied between 0.02 and 18 nmol/m3 throughout the study with a median of 0.4 nmol/m3. ?34S values ranged between 0 and +11%. Concentrations and ?34S values aboard the Amundsen were much more diverse with concentrations ranging between 0.09 and 134 nmol/m3 (2007 median = 9.4 nmol/m3; 2008 median = 2.0 nmol/m3) and ?34S values ranging between -15 and +18%. High concentrations of SO2 on board the Amundsen were not directly from the Amundsen itself as there was no correlation with peaks in coincident CO2 measurements. Low concentrations of SO2 may, in a few instances, be associated with DMS oxidation. Negative ?34S values were present for samples collected near the Amundsen Gulf and are consistent with a third source of SO2 in the Arctic. This is likely the local source of SO2 from the Smoking Hills in the North West Territories. Distinguishing between these sources of SO2 in the Arctic and the importance of local verses regional sources will be discussed.

Norman, A. L.; Seguin, A.; Rempillo, O. T.

2011-12-01

304

Yield response curves of crops exposed to SO 2 time series  

NASA Astrophysics Data System (ADS)

Six species (alfalfa, onion, lettuce, radish, red clover, Douglas fir) were exposed in field growth chambers to both constant concentration and stochastic SO 2 time series. Yield response curves were generated with median concentrations ranging from 0 to 20 pphm. Constant concentration treatments were found to underestimate yield loss compared with the pollutant time series treatments. An heuristic model of plant assimilation of SO 2 is presented to explain this result.

Male, Larry; Preston, Eric; Neely, Grady

305

The influence of SO2 environments on immersion silver finished PCBs by mixed flow gas testing  

Microsoft Academic Search

This study focuses on the corrosion of immersion silver (ImAg) finished copper land patterns on printed circuit boards (PCBs) due to SO2 exposure in a mixed flow gas chamber. Six test conditions were examined with varying concentrations, temperatures, relative humidity, and exposure times. The results indicated that there are two mechanisms of corrosion on ImAg-finished PCBs in an SO2 gas

Shunong Zhang; Anshul Shrivastava; Michael Osterman; Michael Pecht; Rui Kang

2009-01-01

306

Global tracking of the SO2 clouds from the June, 1991 Mount Pinatubo eruptions  

Microsoft Academic Search

The explosive June 1991 eruptions of Mount Pinatubo produced the largest sulfur dioxide cloud detected by the Total Ozone Mapping Spectrometer (TOMS) during its 13 years of operation: approximately 20 million tons of SO2, predominantly from the cataclysmic June 15th eruption. The SO2 cloud observed by the TOMS encircled the Earth in about 22 days (?21 m\\/s); however, during the

Gregg J. S. Bluth; Scott D. Doiron; Charles C. Schnetzler; Arlin J. Krueger; Louis S. Walter

1992-01-01

307

Direct Sulfonation of Methane to Methanesulfonic Acid with SO2 Using Ca Salts as Promoters  

E-print Network

@cchem.berkeley.edu Selective catalytic functionalization of methane to value-added products is a subject of considerable-pressure, glass-lined autoclave.9 K2S2O8 and a catalytic amount of a Ca salt (or salts of other metals) were added as the ratio of the moles of SO2 converted to MSA to total moles of SO2 taken initially. No other byproducts

Bell, Alexis T.

308

Modification of Activated Carbon Fiber by Loading Metals and Their Performance on SO 2 Removal  

Microsoft Academic Search

Metal-loaded activated carbon fibers (ACFs) were prepared by impregnation and characterized by N2 adsorption at 77K, XRD, XPS and SEM. Their properties on SO2 removal were examined in a tubular fixed bed reactor with a model flue gas. Cobalt-loaded ACF showed the best activity among the prepared metal-loaded ACFs and a constant removal ratio of SO2 above 87% during continuous

Jianying WANG; Fengyun ZHAO; Yongqi HU; Ruihong ZHAO; Runjing LIU

2006-01-01

309

Catalytic removal of SO 2 over ammonia-activated carbon fibers  

Microsoft Academic Search

Nitrogen-containing functional groups were introduced onto the surface of activated carbon fibers (ACF) by activating an ethylene tar pitch-based carbon fiber with ammonia water. The activity of the ACF for the conversion of SO2 to aq. H2SO4 in the presence of H2O and O2 is significantly higher than that of other commercial ACF studied before. Both the SO2 adsorption capacity

Kaixi Li; Licheng Ling; Chunxiang Lu; Wenming Qiao; Zhenyu Liu; Lang Liu; I. Mochida

2001-01-01

310

Identification of Large Emission Sources of SO2 in Mexico Megacity  

NASA Astrophysics Data System (ADS)

Successful actions for reducing SO2 concentrations in the Mexico Megacity such as changes in fuel composition for industry and cars, closure of large emitters and the setup of a measuring network of criteria pollutants, took place in the last 15 years. Specifically SO2 has been measured systematically since 1986. However there are still some periods of high SO2 concentrations, exceeding the recommended World Health Organization levels. Using a coupled air quality model and back trajectories analysis, it was possible to identify the large SO2 emissions sources that influence the air quality of Mexico Megacity for the years 2007 to 2009. Two large sources were identified in previous studies: The Tula industrial area and the Popocatepetl volcano. However those only explain only around 70% of the high SO2 concentrations modeled episodes. An additional source has been identified to explain this missing contribution. It is the Tuxpan power plant located in the coast of the Gulf of Mexico. This shows that near and distant regional sources should be involved to explain the increment of atmospheric SO2 concentrations for Mexico Megacity and other areas were so far no measurements are available. A control policy should be at a national level

Garcia-reynoso, J.; Resendiz-Martinez, C.; Delgado Granados, H.

2011-12-01

311

Effect of surface area and chemisorbed oxygen on the SO2 adsorption capacity of activated char  

USGS Publications Warehouse

The objective of this study was to determine whether activated char produced from Illinois coal could be used effectively to remove sulfur dioxide from coal combustion flue gas. Chars were prepared from a high-volatile Illinois bituminous coal under a wide range of pyrolysis and activation conditions. A novel char preparation technique was developed to prepare chars with SO2 adsorption capacities significantly greater than that of a commercial activated carbon. In general, there was no correlation between SO2 adsorption capacity and surface area. Temperature-programmed desorption (TPD) was used to determine the nature and extent of carbon-oxygen (C-O) complexes formed on the char surface. TPD data revealed that SO2 adsorption was inversely proportional to the amount of C-O complex. The formation of a stable C-O complex during char preparation may have served only to occupy carbon sites that were otherwise reactive towards SO2 adsorption. A fleeting C(O) complex formed during SO2 adsorption is postulated to be the reaction intermediate necessary for conversion of SO2 to H2SO4. Copyright ?? 1996 Elsevier Science Ltd.

Lizzio, A.A.; DeBarr, J.A.

1996-01-01

312

Exploring the Capabilities of Satellite Observation of Anthropogenic Sulfur Dioxide (SO2) in the Lower Atmosphere  

NASA Astrophysics Data System (ADS)

Anthropogenic activities, such as fuel combustion, oil refining, and metal smelting, emit sulfur dioxide (SO2) into the atmospheric planetary boundary layer (PBL), leading to air quality degradation near the source regions. SO2 in the air is oxidized to form sulfate aerosols, which may have a significant impact on regional air quality and climate. Sulfate aerosols are usually removed from the atmosphere through acid deposition, which can damage the environment and ecosystems. SO2 and sulfate aerosols are sometimes lifted into the middle or upper troposphere and subsequently transported over long distances, affecting remote regions. Space-borne UV instruments, such as Aura/OMI, MetOp/GOME-2, and NPP/OMPS, provide a unique perspective on the spatial and temporal distribution of SO2 over the globe. In this presentation, we will describe the recent advances in retrieval algorithm that provide improved detection and quantification of PBL SO2, and compare the new retrievals with the operational OMI SO2 products to show significant reduction in noise and bias. We will also present validation results obtained by the comparisons with co-located in-situ aircraft measurements to illustrate improved accuracy achieved with the advanced algorithm.

Yang, K.; Krotkov, N. A.; Li, C.; He, H.; Dickerson, R. R.

2012-12-01

313

Characterization of SO2 abundance in Venus' night-side mesosphere from SPICAV/VEX observations  

NASA Astrophysics Data System (ADS)

Sulfur dioxide (SO _{2}) is a key component of Venus’ atmosphere since the planet is totally covered by H _{2}SO _{4} droplets clouds at altitudes 50-70 km. Any significant change in the SO _{x} oxides above and within the clouds affects the photochemistry in the mesosphere (70-120 km). Recent continuous observations from the Venus Express orbiter (Belyaev et al., 2012; Marcq et al., 2013) and ground-based telescopes (Sandor et al., 2010; Krasnopolsky, 2010; Encrenaz et al., 2012) showed high variability of SO _{2} abundance with years, diurnal time and latitude on the day-side and terminators (commonly from 20 to 500 ppbv above the clouds). In the night-side mesosphere SO _{2} is not photo dissociative but, so far, its behavior has never been explored in details. In this paper we present first results from sulfur dioxide observations made by SPICAV UV spectrometer onboard Venus Express orbiter in regime of stellar occultation (Bertaux et al., 2007). In this mode the instrument observes night-side mesosphere and can register SO _{2} absorption bands in 190-220 nm and CO _{2} bands in 120-200 nm at altitudes from 85 to 110 km (spectral resolution is ˜2 nm). As a result, vertical distribution of SO _{2} and CO _{2} concentrations has been retrieved in observation period from June 2006 to April 2012, at latitude range 60(°) S-60(°) N and Venus local time 20:00-04:00. On the average, mixing ratio of sulfur dioxide fluctuates around ˜100 ppbv along altitude range 90-100 km. Our work is supported by the Program ?22 of RAS and grant of the Russian Government to MIPT. References: Belyaev D. et al., 2012. Vertical profiling of SO _{2} and SO above Venus' clouds by SPICAV/SOIR solar occultations. Icarus 217, 740-751. Bertaux J.-L. et al., 2007. SPICAV on Venus Express: three spectrometers to study the global structure and composition of Venus atmosphere. Planet. Space Sci. 55, 1673-1700. Encrenaz T. et al., 2012. HDO and SO _{2} thermal mapping on Venus: evidence for strong SO _{2} variability. A&A 543, A153. Krasnopolsky V.A., 2010. Spatially-resolved high-resolution spectroscopy of Venus. 2. Variations of HDO, OCS, and SO _{2} at the cloud tops. Icarus 209, 314-322. Marcq E. et al., 2013. Variations of sulphur dioxide at the cloud top of Venus’s dynamic atmosphere. Nature Geoscience, vol. 6, 25-28. DOI: 10.1038/NGEO1650. Sandor B.J. et al., 2010. Sulfur chemistry in the Venus mesosphere from SO _{2} and SO microwave spectra. Icarus 208, 49-60.

Belyaev, Denis; Fedorova, Anna; Piccialli, Arianna; Marcq, Emmanuel; Montmessin, Franck; Bertaux, Jean-Loup; Evdokimova, Daria

314

Radiative transfer effects of high SO2 and aerosol loads during major volcanic eruptions  

NASA Astrophysics Data System (ADS)

Satellite remote sensing of volcanic emissions nowadays allow to globally track and quantify large plumes after major eruptions. Especially the detection of sulphur dioxide (SO2) via Differential Optical Absorption Spectroscopy (DOAS) has become one of the most common applications to monitor the input of gaseous volcanic species into the Earth's atmosphere. While SO2 can be spectroscopically identified because of its strong absorption bands in the UV, the DOAS method can usually only be applied for optical weak absorbers. However, if the SO2 loading of the atmosphere becomes very high, which may occur in the course of a strong volcanic eruption, the atmosphere can no longer be considered transparent throughout the commonly used wavelength range of evaluation between 300 and 325 nm. The associated radiative transfer usually results in a strong underestimation of the SO2 slant column density (SCD), mainly because the solar radiation that is detected by the satellite instruments has only penetrated the outermost layers of the SO2-rich volcanic plume. In order to overcome this problem, we recently proposed to use a combination of results from the standard and additional alternative fit windows at longer wavelengths (326.5-335 nm and/or 360-390 nm). Here, the SO2 absorption cross-section is generally weak, but sufficiently strong for the detection of very high SO2 loads. A first comparison of the results showed that generally a typical relationship can be identified between SO2 SCDs from different evaluation wavelength ranges. However, occuring differences for some observations can only be explained by the additional influences of large amounts of volcanic aerosols on radiative transfer. We present first results from a study on the possible characterisation of volcanic aerosol properties and thereby associated impacts of the radiative transfer on the SO2 DOAS retrieval at different fit windows. Satellite observations of the SO2 column densities and UV Aerosol Indices (UVAI) by the Ozone Monitoring Instrument (OMI) as well as the Global Ozone Monitoring Instrument (GOME-2) will be analysed and supported by simulations with the Monte-Carlo radiative transfer model McArtim for the volcanic eruption of the Kasatochi volcano in August 2008.

Hörmann, Christoph; Penning de Vries, Marloes; Beirle, Steffen; Wagner, Thomas

2014-05-01

315

Effect of the volcanic ash type uncertainties on ash and SO2 retrievals from satellite multi-spectral measurements in the TIR spectral range  

NASA Astrophysics Data System (ADS)

After the Eyjafjallajokull 2010 eruption the quantitative determination of the volcanic ash present in ash clouds has become more important because of the policy change from the previous zero tolerance to the new ash threshold based approach in the aviation hazard management. Volcanic SO2 has an impact on the environment and when injected at high altitudes can be oxidized to form sulphates capable of reflecting solar radiation then causing surface cooling. Observations of the volcanic degassing also yield insights into the magmatic processes which control volcanic activity during both quiescent and eruptive phases. During volcanic eruptions ash and gases are often emitted simultaneously. The plume ash particles reduce the top of atmosphere radiance in the entire thermal infrared (TIR) spectral range causing a significant SO2 columnar abundance overestimation. The ash optical properties are among the most critical parameters to set, their uncertainties cause meaningful errors on both ash and SO2 retrievals. In this work the effect effect of the volcanic ash type uncertainties on ash and SO2 retrievals from MODIS measurements in the TIR spectral range have been quantified. As test case some events of the 2010 Eyjafjallajokull (Iceland) eruption has been considered. The ash optical properties derive from the ARIA database of the Oxford University, while the MODIS SO2 and ash retrievals strategies are based on the BTD and minimization approaches using the channels centered at 8.7, 11 and 12 micron. The radiative transfer model simulations, needed for the retrievals schemes, are carried out by using MODTRAN [Corradini et al., 2009]. The MODIS SO2 retrievals have been also compared with the retrievals obtained by using IASI hyper-spectral and ASTER high spatial resolution data. The two procedures are considered less sensitive to the ash type: the ASTER retrieval scheme [Campion et al. 2010] consists of adjusting the SO2 column amount until the ratios of radiance simulated on several ASTER bands match the observations, while the IASI retrieval [Carboni et al. 2012] is an optimal estimation scheme that exploit the high resolution spectrometer measurements of the two SO2 absorption bands around 7.3 and 8.7 micron.

Corradini, Stefano; Merucci, Luca; Campion, Robin; Carboni, Elisa

2013-04-01

316

Applying UV cameras for SO2 detection to distant or optically thick volcanic plumes  

USGS Publications Warehouse

Ultraviolet (UV) camera systems represent an exciting new technology for measuring two dimensional sulfur dioxide (SO2) distributions in volcanic plumes. The high frame rate of the cameras allows the retrieval of SO2 emission rates at time scales of 1 Hz or higher, thus allowing the investigation of high-frequency signals and making integrated and comparative studies with other high-data-rate volcano monitoring techniques possible. One drawback of the technique, however, is the limited spectral information recorded by the imaging systems. Here, a framework for simulating the sensitivity of UV cameras to various SO2 distributions is introduced. Both the wavelength-dependent transmittance of the optical imaging system and the radiative transfer in the atmosphere are modeled. The framework is then applied to study the behavior of different optical setups and used to simulate the response of these instruments to volcanic plumes containing varying SO2 and aerosol abundances located at various distances from the sensor. Results show that UV radiative transfer in and around distant and/or optically thick plumes typically leads to a lower sensitivity to SO2 than expected when assuming a standard Beer–Lambert absorption model. Furthermore, camera response is often non-linear in SO2 and dependent on distance to the plume and plume aerosol optical thickness and single scatter albedo. The model results are compared with camera measurements made at Kilauea Volcano (Hawaii) and a method for integrating moderate resolution differential optical absorption spectroscopy data with UV imagery to retrieve improved SO2 column densities is discussed.

Kern, Christoph; Werner, Cynthia; Elias, Tamar; Sutton, A. Jeff; Lübcke, Peter

2013-01-01

317

Validation of SO2 Retrievals from the Ozone Monitoring Instrument over NE China  

NASA Technical Reports Server (NTRS)

The Dutch-Finnish Ozone Monitoring Instrument (OMI) launched on the NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space-based UV measurements of sulfur dioxide (SO2). We present a first validation of the OMI SO2 data with in situ aircraft measurements in NE China in April 2005. The study demonstrates that OMI can distinguish between background SO2 conditions and heavy pollution on a daily basis. The noise (expressed as the standard deviation,sigma) is approximately 1.5 DU (Dobson units; 1 DU = 2.69 10 (exp 16) molecules/cm (exp 2)) for instantaneous field of view boundary layer (PBL) SO2 data. Temporal and spatial averaging can reduce the noise to sigma approximetly 0.3 DU over a remote region of the South Pacific; the long-term average over this remote location was within 0.1 DU of zero. Under polluted conditions collection 2 OMI data are higher than aircraft measurements by a factor of two. Improved calibrations of the radiance and irradiance data (collection 3) result in better agreement with aircraft measurements on polluted days. The air mass corrected collection 3 data still show positive bias and sensitivity to UV absorbing aerosols. The difference between the in situ data and the OMI SO2 measurements within 30 km of the aircraft profiles was about 1 DU, equivalent to approximately 5 ppb from 0 to 3000 m altitude. Quantifying the SO2 and aerosol profiles and spectral dependence of aerosol absorption between 310 and 330 nm are critical for an accurate estimate of SO2 from satellite UV measurements.

Krotkov, Nickolay A.; McClure, Brittany; Dickerson, Russell R.; Carn, Simon A.; Li, Can; Bhartia, Pawan K.; Yang, Kai; Krueger, Arlin J.; Li, Zhanqing; Levelt, Pieternel F.; Chen, Hongbin; Wang, Pucai; Lu, Daren

2008-01-01

318

iFit and Light Dilution: Ultraviolet volcanic SO2 measurements under the microscope  

NASA Astrophysics Data System (ADS)

Volcanic SO2 flux measurement systems are a staple of volcano monitoring networks, as this volcanic gas flux reflects the magma input rate into the volcano's feeding system. SO2 flux monitoring has been used since the seventies, with some notable successes at Pinatubo, Mt. St. Helens, Montserrat and Italian volcanoes. However, there are some subtle aspects of the atmospheric radiative transfer processed inherent in the technique which have been ignored for many years; or perhaps better, they have been forgotten, as these subtleties were clearly spelt out in early COSPEC papers by Millán and co-workers. Recent work by Kern et al. (2010, 2012) has re-focussed attention on the light dilution effect during SO2 plume measurements. This occurs when solar radiation is scattered into the slant column observed by a UV spectrometer or imaging system below the height of the volcanic plume, such that it has not passed through the plume. This below-plume light dilutes the SO2 absorption produced by light passing through the plume from above, apparently reducing the amount of SO2 present. Fortunately, the light dilution process leaves a signature in the shape of the SO2 absorption spectrum, due to the non-linear behaviour of absorption lines with respect to gas amount, following the Beer-Lamber law. This signature can be used to quantify the magnitude of the light dilution in real field spectra. We developed a new intensity spectrum UV fitting code called iFit that allows fitting of the light dilution signature, and applied this to examples from Stromboli and Etna. here we summarise the results from these studies and highlight the importance of this previously ignored process for quantify SO2 gas emissions from volcanoes.

Burton, Michael; Sawyer, Georgina

2013-04-01

319

Applying UV cameras for SO2 detection to distant or optically thick volcanic plumes  

NASA Astrophysics Data System (ADS)

Ultraviolet (UV) camera systems represent an exciting new technology for measuring two dimensional sulfur dioxide (SO2) distributions in volcanic plumes. The high frame rate of the cameras allows the retrieval of SO2 emission rates at time scales of 1 Hz or higher, thus allowing the investigation of high-frequency signals and making integrated and comparative studies with other high-data-rate volcano monitoring techniques possible. One drawback of the technique, however, is the limited spectral information recorded by the imaging systems. Here, a framework for simulating the sensitivity of UV cameras to various SO2 distributions is introduced. Both the wavelength-dependent transmittance of the optical imaging system and the radiative transfer in the atmosphere are modeled. The framework is then applied to study the behavior of different optical setups and used to simulate the response of these instruments to volcanic plumes containing varying SO2 and aerosol abundances located at various distances from the sensor. Results show that UV radiative transfer in and around distant and/or optically thick plumes typically leads to a lower sensitivity to SO2 than expected when assuming a standard Beer-Lambert absorption model. Furthermore, camera response is often non-linear in SO2 and dependent on distance to the plume and plume aerosol optical thickness and single scatter albedo. The model results are compared with camera measurements made at Kilauea Volcano (Hawaii) and a method for integrating moderate resolution differential optical absorption spectroscopy data with UV imagery to retrieve improved SO2 column densities is discussed.

Kern, Christoph; Werner, Cynthia; Elias, Tamar; Sutton, A. Jeff; Lübcke, Peter

2013-07-01

320

Thermodynamic models of the chemistry of lunar volcanic gases  

NASA Technical Reports Server (NTRS)

Thermodynamic models and mass-balance arguments are used to constrain the chemistry of lunar volcanic gases. The results predict that lunar gases were dominated by reduced C and S gases such as CO, COS, CS2, S2. The more oxidized gases CO2 and SO2 were also important, but only in limited temperature ranges. Gases such as Cl2, CCl4, and CF4 were more abundant than HF and HCl, which were the two major H compounds in the lunar gases. Chlorides and fluorides were important species for transporting many volatile and ore-forming metals, and the implications for fractionating and concentrating metals into lunar ore-deposits merit further study.

Fegley, Bruce, Jr.

1991-01-01

321

An integrated study of SO2 degassing from Tungurahua volcano, Ecuador  

NASA Astrophysics Data System (ADS)

Tungurahua is a 5023 m-high stratovolcano in Ecuador, with an estimated long-term mean SO2 output of 1458 ± 2026 t/day. Since 2006, gas emissions from Tungurahua have been continuously monitored by UV DOAS spectrometers installed as part of the Network for Observation of Volcanic and Atmospheric Change (NOVAC) programme. The SO2 emissions from the volcano have also been observed and characterised by the satellite-based UV spectrometer OMI (Ozone Monitoring Instrument). Tungurahua is therefore an ideal location for comparing ground- and satellite-based estimates of volcanic SO2 emissions. Although OMI SO2 retrievals for continuous tropospheric degassing are not yet validated, the dataset represents a large and mostly untapped resource for volcano monitoring, particularly in remote or inaccessible regions. This novel study seeks to improve agreement between the DOAS and OMI datasets for Tungurahua, and gain new understanding of why differences in the two estimates of SO2 degassing arise. Uncertainties affecting comparison between the datasets include: the different natures of the quantities measured (flux vs column concentration); the impact of local atmospheric and meteorological conditions (e.g. clouds masking volcanic plumes; humidity and temperature promoting rapid loss of SO2 via oxidation to sulphate or by various wet/dry deposition processes; wind dispersal of plumes); and differences in the spatial and temporal resolution of measurements. We present a novel numerical modelling-based study of volcanic SO2 emissions from Tungurahua using the atmospheric chemistry/transport model REMOTE, which has already been successfully applied to modelling post-emission SO2 dispersion from volcanoes in Nicaragua and Indonesia. We also investigate the use of derived fluxes from instantaneous satellite scenes to provide better agreement with ground-based gas emission measurements. Total daily atmospheric SO2 burdens for the REMOTE and OMI datasets are compared, and we use REMOTE's treatment of atmospheric chemical reactions, wind dispersal, and cloud cover, as well as additional OMI data products (effective reflectivity and aerosol index) and ground-based observatory records to interpret the variation in agreement between the two datasets. A key aim is to identify whether any of the above sources of uncertainty are dominant, and to investigate potential means of correcting for these. Additionally, we seek to produce a detailed assessment of errors in each dataset.

McCormick, Brendan; Herzog, Michael; Yang, Jian; Edmonds, Marie; Mather, Tamsin; Carn, Simon; Hidalgo, Silvana; Langmann, Baerbel

2013-04-01

322

Improved modelling of ship SO 2 emissions—a fuel-based approach  

NASA Astrophysics Data System (ADS)

Significant variations are apparent between the various reported regional and global ship SO 2 emission inventories. Important parameters for SO 2 emission modelling are sulphur contents and marine fuel consumption. Since 1993, the global average sulphur content for heavy fuel has shown an overall downward trend, while the bunker sale has increased. We present an improved bottom up approach to estimate marine sulphur emissions from ship transportation, including the geographical distribution. More than 53,000 individual bunker samples are used to establish regionally and globally (volume) weighted average sulphur contents for heavy and distillate marine fuels. We find that the year 2002 sulphur content in heavy fuels varies regionally from 1.90% (South America) to 3.07% (Asia), with a globally weighted average of 2.68% sulphur. The calculated globally weighted average content for heavy fuels is found to be 5% higher than the average (arithmetic mean) sulphur content commonly used. The reason for this is likely that larger bunker stems are mainly of high-viscosity heavy fuel, which tends to have higher sulphur values compared to lower viscosity fuels. The uncertainties in SO 2 inventories are significantly reduced using our updated SO 2 emission factors (volume-weighted sulphur content). Regional marine bunker sales figures are combined with volume-weighted sulphur contents for each region to give a global SO 2 emission estimate in the range of 5.9-7.2 Tg (SO 2) for international marine transportation. Also taking into account the domestic sales, the total emissions from all ocean-going transportation is estimated to be 7.0-8.5 Tg (SO 2). Our estimate is significantly lower than recent global estimate reported by Corbett and Koehler [2003. Journal of Geophysical Research: Atmospheres 108] (6.49 Tg S or about 13.0 Tg SO 2). Endresen et al. [2004. Journal of Geophysical Research 109, D23302] claim that uncertainties in input data for the activity-based method will give too high emission estimates. We also indicate that this higher estimate will almost give doubling of regional emissions, compared to detailed movement-based estimates. The paper presents an alternative approach to estimate present overall SO 2 ship emissions with improved accuracy.

Endresen, Øyvind; Bakke, Joachim; Sørgård, Eirik; Flatlandsmo Berglen, Tore; Holmvang, Per

323

SO2 photolysis as a source for sulfur mass-independent isotope signatures in stratospehric aerosols  

NASA Astrophysics Data System (ADS)

Signatures of sulfur isotope mass-independent fractionation (S-MIF) have been observed in stratospheric sulfate aerosols deposited in polar ice. The S-MIF signatures are thought to be associated with stratospheric photochemistry following stratospheric volcanic eruptions, but the exact mechanism responsible for the production and preservation of these signatures is debated. In order to identify the origin and the mechanism of preservation for these signatures, a series of laboratory photochemical experiments were carried out to investigate the effect of temperature and added O2 on the S-MIF produced by two absorption band systems of SO2: photolysis in the 190 to 220 nm region and photoexcitation in the 250 to 350 nm region. The SO2 photolysis (SO2 + h? ? SO + O) experiments showed S-MIF signals with large 34S/34S fractionations, which increases with decreasing temperature. The overall S-MIF pattern observed for photolysis experiments, including high 34S/34S fractionations, positive mass-independent anomalies in 33S, and negative anomalies in 36S, is consistent with a major contribution from optical isotopologue screening effects and data for stratospheric sulfate aerosols. In contrast, SO2 photoexcitation produced products with positive S-MIF anomalies in both 33S and 36S, which is different from stratospheric sulfate aerosols. SO2 photolysis in the presence of O2 produced SO3 with S-MIF signals, suggesting the transfer of the S-MIF anomalies from SO to SO3 by the SO + O2 + M ? SO3 + M reaction. This is supported with energy calculations of stationary points on the SO3 potential energy surfaces, which indicate that this reaction occurs slowly on a single adiabatic surface, but that it can occur more rapidly through intersystem crossing. Based on our experimental results, we estimate a termolecular rate constant on the order of 10-37 cm6 molecule-2 s-1. This rate can explain the preservation of mass independent isotope signatures in stratospheric sulfate aerosols and provides a minor, but important, oxidation pathway for stratospheric SO2. The production and preservation of S-MIF signals requires a high SO2 column density to allow for optical isotopologue screening effects to occur and to generate a large enough signature that it can be preserved. In addition, the SO2 plume must reach an altitude of around 20 to 25 km, where SO2 photolysis becomes a dominant process. These experiments are the first step towards understanding the origin of the sulfur isotope anomalies in stratospheric sulfate aerosols.

Whitehill, A. R.; Jiang, B.; Guo, H.; Ono, S.

2015-02-01

324

A neural network approach for monitoring of volcanic SO2 and cloud height using hyperspectral measurements  

NASA Astrophysics Data System (ADS)

In this study two neural networks were implemented in order to emulate a retrieval model and to estimate the sulphur dioxide (SO2) columnar content and cloud height from volcanic eruption. ANNs were trained using all Infrared Atmospheric Sounding Interferometer (IASI) channels in Thermal Infrared (TIR) as inputs, and the corresponding values of SO2 content and height of volcanic cloud obtained using the Oxford SO2 retrievals as target outputs. The retrieval is demonstrated for the eruption of the Eyjafjallajökull volcano (Iceland) occurred in 2010 and to three IASI images of the Grímsvötn volcanic eruption that occurred in May 2011, in order to evaluate the networks for an unknown eruption. The results of validation, both for Eyjafjallajökull independent data-sets, provided root mean square error (RMSE) values between neural network outputs and targets lower than 20 DU for SO2 total column and 200 mb for cloud height, therefore demonstrating the feasibility to estimate SO2 values using a neural network approach, and its importance in near real time monitoring activities, owing to its fast application. Concerning the validation carried out with neural networks on images from the Grímsvötn eruption, the RMSE of the outputs remained lower than the Standard Deviation (STD) of targets, and the neural network underestimated retrieval only where target outputs showed different statistics than those used during the training phase.

Piscini, Alessandro; Carboni, Elisa; Del Frate, Fabio; Grainger, Roy Gordon

2014-10-01

325

IASI observations of sulfur dioxide (SO2) in the boundary layer of Norilsk  

NASA Astrophysics Data System (ADS)

Norilsk is one of the most polluted cities in the world, largely because of intense mining of heavy metals. Here we present satellite observations of SO2 in a large area surrounding the city, derived from 4 years of measurements from the Infrared Atmospheric Sounding Interferometer (IASI), the nadir thermal infrared (TIR) sounder onboard the MetOp platforms. TIR instruments are conventionally considered to be inadequate for monitoring near-surface composition, because their sensitivity to the lowest part of the atmosphere is limited by the thermal contrast between the ground and the air above it. We demonstrate that IASI is capable of measuring SO2 (here as a partial column from 0 to 2 km) in Norilsk, thanks to the large temperature inversions and the low humidity in wintertime. We discuss the influence of thermal contrast and of surface humidity on the SO2 retrieved columns and estimate the retrieval errors. Using a simple box model, we derive the yearly total emissions of SO2 from Norilsk and compare them to previously reported values. More generally, we present in this work the first large-scale demonstration of the capability of space-based TIR sounders to measure near-surface SO2 anthropogenic pollution.

Bauduin, Sophie; Clarisse, Lieven; Clerbaux, Cathy; Hurtmans, Daniel; Coheur, Pierre-François

2014-04-01

326

The Heidelberg Airborne Imaging DOAS Instrument (HAIDI) - a novel imaging DOAS device for 2-D and 3-D imaging of trace gases and aerosols  

NASA Astrophysics Data System (ADS)

Many relevant processes in tropospheric chemistry take place on rather small scales (e.g., tens to hundreds of meters) but often influence areas of several square kilometer. Thus, measurements of the involved trace gases with high spatial resolution are of great scientific interest. In order to identify individual sources and sinks and ultimately to improve chemical transport models, we developed a new airborne instrument, which is based on the well established Differential Optical Absorption Spectroscopy (DOAS) method. The Heidelberg Airborne Imaging DOAS Instrument (HAIDI) is a passive imaging DOAS spectrometer, which is capable of recording horizontal and vertical trace gas distributions with a resolution of better than 100 m. Observable species include NO2, HCHO, C2H2O2, H2O, O3, O4, SO2, IO, OClO and BrO. Here we give a technical description of the instrument including its custom-built spectrographs and CCD detectors. Also first results from measurements with the new instrument are presented. These comprise spatial resolved SO2 and BrO in volcanic plumes, mapped at Mt. Etna (Sicily, Italy), NO2 emissions in the metropolitan area of Indianapolis (Indiana, USA) as well as BrO and NO2 distributions measured during arctic springtime in context of the BRomine, Ozone, and Mercury EXperiment (BROMEX) campaign, which was performed 2012 in Barrow (Alaska, USA).

General, S.; Pöhler, D.; Sihler, H.; Bobrowski, N.; Frieß, U.; Zielcke, J.; Horbanski, M.; Shepson, P. B.; Stirm, B. H.; Simpson, W. R.; Weber, K.; Fischer, C.; Platt, U.

2014-10-01

327

The Heidelberg Airborne Imaging DOAS Instrument (HAIDI) - a novel Imaging DOAS device for 2-D and 3-D imaging of trace gases and aerosols  

NASA Astrophysics Data System (ADS)

Many relevant processes in tropospheric chemistry take place on rather small scales (e.g. tens to hundreds of meters) but often influence areas of several square kilometer. Thus, measurements of the involved trace gases with high spatial resolution are of great scientific interest. In order to identify individual sources and sinks and ultimately to improve chemical transport models, we developed a new airborne instrument, which is based on the well established DOAS method. The Heidelberg Airborne Imaging Differential Optical Absorption Spectrometer Instrument (HAIDI) is a passive imaging DOAS spectrometer, which is capable of recording horizontal and vertical trace gas distributions with a resolution of better than 100 m. Observable species include NO2, HCHO, C2H2O2, H2O, O3, O4, SO2, IO, OClO and BrO. Here we report a technical description of the instrument including its custom build spectrographs and CCD detectors. Also first results from measurements with the new instrument are presented. These comprise spatial resolved SO2 and BrO in volcanic plumes, mapped at Mt. Etna (Sicily, Italy), NO2 emissions in the metropolitan area of Indianapolis (Indiana, USA) as well as BrO and NO2 distributions measured during arctic springtime in context of the BROMEX campaign, which was performed 2012 in Barrow (Alaska, USA).

General, S.; Pöhler, D.; Sihler, H.; Bobrowski, N.; Frieß, U.; Zielcke, J.; Horbanski, M.; Shepson, P. B.; Stirm, B. H.; Simpson, W. R.; Weber, K.; Fischer, C.; Platt, U.

2014-03-01

328

The NO 2/NO x ratio in emissions from gasoline-powered cars: High NO 2 percentage in idle engine measurements  

NASA Astrophysics Data System (ADS)

Measurements of the fraction of NO 2 in NO x emissions from a gasoline-powered passenger car showed, that when idling NO 2/NO x (v/v) goes as high as ~ 0.3 for a warm engine. This should be compared with the widely accepted assumption that gasoline cars emit 2-5 % of NO x in the form of NO 2. It can be concluded, that the NO 2 concentration in the exhaust gases from an idle engine is some four times as high as the NO 2 concentration in exhausts from a car driven at 40 km h -1. The high NO 2/NO x ratio, built up at rush hours in Swedish cities, may thus be rationalized as direct emissions from idling gasoline-powered cars.

Lenner, Magnus; Lindqvist, Oliver; Rosén, Åke

329

Structures and conformational properties of trifluoromethylsulfonyl isocyanate, CF 3SO 2NCO, and trifluoromethylsulfonyl azide, CF 3SO 2N 3  

NASA Astrophysics Data System (ADS)

The geometric structures of trifluoromethylsulfonyl isocyanate, CF 3SO 2NCO, and trifluoromethylsulfonyl azide, CF 3SO 2N 3, have been determined by gas electron diffraction and by theoretical methods ( {HF}/{6-31 G? }, {HF}/{6-31 G? }, {MP2 }/{6-31 G? }, {B3 P91 }/{6-31 G? }. Both compounds possess a single conformation with eclipsed or nearly eclipsed orientation of the NCO or N 3 group relative to one S?O double bond and dihedral angles ø(O?S?N?C) = 4(8)° and ø(O?S?N?N) = - 24(6)°. The negative sign indicates that the azide group is rotated towards the CF 3 group. The S?N bonds in both compounds are very similar (1.653(5) and 1.668(4) Å, respectively). The nitrogen bond angle in the isocyanate (S?N?C = 126.5(15)°) is larger by 15° than that in the azide (S?N?N = 111.6(15)°). All theoretical methods reproduce the experimental structures satisfactorily except for the S?C and S?N bond lengths.

Haist, Ralph; Mack, Hans Georg; Della Védova, Carlos O.; Cutín, Edgardo H.; Oberhammer, Heinz

1998-04-01

330

Polyvinylpyrrolidone/reduced graphene oxide nanocomposites thin films coated on quartz crystal microbalance for NO2 detection at room temperature  

NASA Astrophysics Data System (ADS)

Polyvinylpyrrolidone (PVP)/reduced graphene oxide (RGO) nanocomposites are sprayed on quartz crystal microbalance (QCM) for NO2 sensing. The thin films are characterized by Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-VIS). The experimental results reveal that PVP/RGO sensor exhibits higher sensitivity and shorter recovery time than those of PVP. Besides, the response to 20 ppm NO2 is higher than other gases such as CO, CO2 and NH3 even at 100ppm. When the PVP/RGO sensor is exposed to these gases, the good selectivity to NO2 makes the sensor ideal for NO2 detection.

Huang, Junlong; Xie, Guangzhong; Zhou, Yong; Xie, Tao; Tai, HuiLing; Yang, Guangjin

2014-08-01

331

Rapid aqueous phase SO2 oxidation in winter fog in the Indo-Gangetic Plain  

NASA Astrophysics Data System (ADS)

Sulphate and sulphur dioxide play an important role in environmental chemistry and climate. The majority of anthropogenic sulphur is released directly as SO2, and a significant fraction of biogenic and natural sulphur emissions are also either directly released as SO2 or oxidised to SO2 in the atmosphere (e.g. H2S, OCS, DMS). Around 50% of global atmospheric sulphur dioxide is then oxidised to sulphate, while the rest is lost through dry and wet deposition. The pathway by which SO2 is oxidised to sulphate is critical in determining the climate forcing and environmental effects of sulphate. Gas-phase oxidation of SO2 by OH radicals or criegee intermediates produces H2SO4 (g), which plays an important role in controlling new particle formation in the troposphere and also modifies the surface properties of hydrophobic particles such as soot and mineral dust. Heterogeneous oxidation of SO2 is considered to occur primarily in cloud droplets, although oxidation on sea salt aerosols and mineral dust surfaces are considered to be regionally important. Heterogeneous oxidation leads to the formation of fewer and larger particles with shorter atmospheric lifetime. The major oxidation pathways which are considered to contribute to sulphate formation in the aqueous phase are oxidation by H2O2 and oxidation by O3 and the lifetime of SO2 with respect to all known loss processes combined is considered to be 1-2 days. Here we report measurements of SO2 measurements from IISER Mohali - Ambient Air Quality Station (30.67°N, 76.73°E), a station located at a suburban site in the Indo Gangetic Basin (IGB) during wintertime (10th Dec. 2011 to 29th Feb. 2012). We use a strong point source of SO2 with known SO2/CO emission ratio (brick kiln) located 6.5 km east of our measurement site to estimate the loss rate of SO2 in wintertime fog in the IGB. We consider the transport from the source to the receptor site to be Lagrangian and use the measured CO concentration at the receptors site to account for changes in the emission intensity (activity pattern) and the dilution of the plume during transport. We see a linear correlation between the measured SO2/CO ratio and the transport time. Binning the data on the basis of relative humidity and applying first order kinetics to SO2 loss within each humidity bin we find the SO2 loss rate with respect to aqueous phase oxidation at our sites varies between > 2.2 x 10-3 mol/cm3/s at 96 % RH and 3.8 x 10-4 mol/cm3/s at 47 % RH. Simple box model calculations reveal that neither oxidation by H2O2 nor oxidation by O3 can account for such rapid SO2 oxidation in the fog water. Considering the high mineral dust loadings are our station (PM 10 typically > 300 ?g/m3) we propose that transition metal catalysis by TMI leached from natural mineral dust and resuspended road dust may be responsible for the rapid oxidation of SO2 in the fog water. However, the observed lifetime with respect to aqueous phase oxidation in wintertime fog is a factor 150-800 times shorter than the lifetime of SO2 with respect to TMI catalyzed oxidation currently implemented in global atmospheric chemistry models. During 2012-2013 winter season we will measure TMI concentrations in the fog water and verify the rates coefficients estimated from the ambient observation by conducting controlled experiments both using collected fog water and different TMI mixtures. If confirmed through laboratory studies our findings have major implications for the SO2 lifetime over the IGP (and possibly other regions with high mineral dust loadings) and will significantly alter the regional direct and indirect aerosol forcing estimates due to anthropogenic SO2 emissions. Acknowledgement: We thank the IISER Mohali Atmospheric Chemistry Facility for data and the Ministry of Human Resource Development (MHRD), India and IISER Mohali for funding the facility. Himanshu acknowledges the DST-INSPIRE Fellowship program. Chinmoy Sarkar thanks the Max Planck-DST India Partner Group on Tropospheric OH reactivity and VOCs for funding the research.

Sachan, Himanshu; Sarkar, Chinmoy; Sinha, Baerbel

2013-04-01

332

Lifetimes and emissions of SO2 from point sources estimated from OMI  

NASA Astrophysics Data System (ADS)

A new method to estimate sulfur dioxide (SO2) lifetimes and emissions from point sources using satellite measurements is described. The method is based on fitting satellite SO2 vertical column density to a three-dimensional parameterization as a function of the coordinates and wind speed. An effective lifetime (or, more accurately, decay time) and emission rate are then determined from the parameters of the fit. The method was applied to measurements from the Ozone Monitoring Instrument (OMI) processed with the new principal component analysis (PCA) algorithm in the vicinity of approximately 50 large U.S. near-point sources. The obtained results were then compared with available emission inventories. The correlation between estimated and reported emissions was about 0.91 with the estimated lifetimes between 4 and 12 h. It is demonstrated that individual sources with annual SO2 emissions as low as 30 kt yr-1 can produce a statistically significant signal in OMI data.

Fioletov, V. E.; McLinden, C. A.; Krotkov, N.; Li, C.

2015-03-01

333

TiO2 Nanotube Array Sensor for Detecting the SF6 Decomposition Product SO2  

PubMed Central

The detection of partial discharge through analysis of SF6 gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO2 nanotube array sensor for detecting the SF6 decomposition product SO2, and the application of the anodic oxidation method for the directional growth of highly ordered TiO2 nanotube arrays. The sensor response of 10–50 ppm SO2 gas is tested, and the sensitive response mechanism is discussed. The test results show that the TiO2 nanotube sensor array has good response to SO2 gas, and by ultraviolet radiation, the sensor can remove attached components very efficiently, shorten recovery time, reduce chemical poisoning, and prolong the life of the components. PMID:22737009

Zhang, Xiaoxing; Zhang, Jinbin; Jia, Yichao; Xiao, Peng; Tang, Ju

2012-01-01

334

New lava lake at Nyamuragira volcano revealed by combined ASTER and OMI SO2 measurements  

NASA Astrophysics Data System (ADS)

We report recent satellite measurements of the SO2 emissions from the Virunga Volcanic Group (VVG), which comprises the very active Nyamuragira and Nyiragongo volcanoes. Combining high time resolution data from the UV-operating OMI (Ozone Monitoring Instrument) with high ground resolution data from the IR-operating ASTER (Advanced Spaceborne Thermal Emission and Reflection radiometer), we show that (1) the SO2 emissions from the VVG have increased severalfold since the end of the last eruption of Nyamuragira. (2) Nyamuragira, which used to have very low intereruptive emissions of SO2 before this eruption, is now contributing to 60 to 90% of the combined emissions measured by OMI. Considering the eruptive history of Nyamuragira, the evidence from previous research for the existence of a shallow magma chamber, and the detection of isolated thermal anomalies since April 2014, we conclude that a deep-seated lava lake has formed in the N pit of Nyamuragira's caldera.

Campion, Robin

2014-11-01

335

Ab initio theoretical study of the interactions between CFCl3 and SO2.  

PubMed

Ab initio calculations have been performed on complexes of CFCl3 with SO2. Ten complexes were found stable, the interaction energies that reflect their stability were corrected by the basis set superposition error and the correction of zero-point energy. The natures of these interactions were investigated by the analysis of natural bond orbital and the atoms in molecules. The results from theoretical calculation indicated that there were the interactions of Cl...O, F...O, Cl...S and F...S between CFCl3 and SO2, furthermore, the non-covalent bonds of Cl...O and Cl...S were the major interaction forces, which provided some data and information for studying the environment problem such as greenhouse effect relevant to CFCl3 and SO2. PMID:19943033

Diao, Kai Sheng; Wang, Fang; Wang, Hai Jun

2010-02-01

336

Investigation of spectral interferences on the accuracy of broadband CW-NIRS tissue SO2 determination  

PubMed Central

An accurate SO2 prediction method for using broadband continuous-wave diffuse reflectance near infrared (NIR) spectroscopy is proposed. The method fitted the NIR spectra to a Taylor expansion attenuation model, and used the simulated annealing method to initialize the nonlinear least squares fit. This paper investigated the effect of potential spectral interferences that are likely to be encountered in clinical use, on SO2 prediction accuracy. The factors include the concentration of hemoglobin in blood, the volume of blood and volume of water in the tissue under the sensor, reduced scattering coefficient, µs', of the muscle, fat thickness and the source-detector spacing. The SO2 prediction method was evaluated on simulated muscle spectra as well as on dual-dye phantoms which simulate the absorbance of oxygenated and deoxygenated hemoglobin. PMID:21258506

Zou, Fengmei; Jin, Chunguang; Ross, Randy R.; Soller, Babs

2010-01-01

337

SO2 emission cap planning for Chengdu-Chongqing economic zone.  

PubMed

The SO2 emission sources of the Chengdu-Chongqing economic zone were divided into 556 emissions units according to four different categories, which are city, industry, point sources, and area sources. The CALPUFF model was used to calculate the contribution of each unit, and consequently obtain an influence-transferring matrix. To ensure that the SO2 concentrations of 46 cities and counties in the Chengdu-Chongqing economic zone meet air quality standards, an emission optimization model was developed to calculate optimal emissions of each emission unit under different development scenarios. The result showed the optimal emissions of SO2 by different provinces and industries. To achieve the target of restricting and optimizing development, corresponding planning programs were developed for every district. PMID:22783625

Yi, Peng; Duan, Ning; Chai, Fahe; Xu, Yaxuan; He, Youjiang

2012-01-01

338

SO(2,4)-covariant quantization of the Maxwell field in conformally flat spaces  

NASA Astrophysics Data System (ADS)

We present an SO(2,4)-covariant quantization of the free electromagnetic field in conformally flat spaces (CFSs). A CFS is realized in a six-dimensional space as an intersection of the null cone with a given surface. The smooth move of the latter is equivalent to perform a Weyl rescaling. This allows to transport the SO(2,4)-invariant quantum structure of the Maxwell field from Minkowski space to any CFS. Calculations are simplified and the CFS Wightman two-point functions are given in terms of their Minkowskian counterparts. The difficulty due to gauge freedom is surpassed by introducing two auxiliary fields and using the Gupta-Bleuler quantization scheme. The quantum structure is given by a vacuum state and creators/annihilators acting on some Hilbert space. In practice, only the Hilbert space changes under Weyl rescalings. Also, the quantum SO(2,4)-invariant free Maxwell field does not distinguish between two CFSs.

Faci, Sofiane

2013-03-01

339

CORRELATION OF ABDOMINAL rSO2 WITH SUPERIOR MESENTERIC ARTERY VELOCITIES IN PRETERM INFANTS  

PubMed Central

Objective Near-infrared spectroscopy (NIRS) is used to monitor brain and kidney perfusion in at-risk premature and term neonates. Although NIRS holds potential for bedside monitoring of intestinal perfusion, there is insufficient evidence showing correlation with mesenteric blood flow. To determine if an association exists between abdominal regional oxygen saturation (A-rSO2) and mesenteric blood flow, we compared changes in A-rSO2 to changes in blood flow velocity in the superior mesenteric artery (SMA) before and after feedings in very-low birthweight infants. Study Design A-rSO2 was continuously monitored midline below the umbilicus for 3 days in 18 stable 25–31 week bolus-fed infants (median BW 1203g, median age 5 days). We compared change in SMA velocity from immediately before to 10 minutes and 60–120 minutes after feeding with change in A-rSO2 over the same time. Spearman’s rank correlation was used to ascertain if a significant association existed. Result Change in A-rSO2 was significantly associated with change in systolic, diastolic, and mean SMA velocity from fasting to 60–120 minutes after feeding (p=0.016, 0.021, 0.010) and from 10 minutes after a feed to 60–120 minutes after feeding (p=0.009, 0.035, 0.032). Conclusion In very preterm infants, A-rSO2 reflects blood flow in the SMA and can provide non-invasive continuous monitoring of intestinal perfusion. Further studies are indicated to determine the sensitivity of NIRS to detect early intestinal pathology in this population. PMID:23392317

Gillam-Krakauer, Maria; Cochran, Caitlin M; Slaughter, James C; Polavarapu, Sruthi; McElroy, Steven J; Hernanz-Schulman, Marta; Engelhardt, Barbara

2013-01-01

340

Infrasound and SO2 Observations of the 2011 Explosive Eruption of Nabro Volcano, Eritrea  

NASA Astrophysics Data System (ADS)

Nabro volcano, Eritrea erupted explosively on 12 June 2011 and produced near continuous emissions and infrasound until mid-July. The eruption disrupted air traffic and severely affected communities in the region. Although the eruption was relatively ash-poor, it produced significant SO2 emissions, including: 1) the highest SO2 column ever retrieved from space (3700 DU), 2) >1.3 Tg SO2 mass on 13 June, and 3) >2 Tg of SO2 for the entire eruption, one of the largest eruptive SO2 masses produced since the 1991 eruption of Mt. Pinatubo. Peak emissions reached well into the stratosphere (~19 km). Although the 12 June eruption was preceded by significant seismicity and clearly detected by satellite sensors, Nabro volcano is an understudied volcano that lies in a remote region with little ground-based monitoring. The Nabro eruption also produced significant infrasound signals that were recorded by two infrasound arrays: I19DJ (Djibouti, 264 km) and I32KE (Kenya, 1708 km). The I19DJ infrasound array detected the eruption with high signal-noise and provides the most detailed eruption chronology available, including eruption onset, duration, changes in intensity, etc. As seen in numerous other studies, sustained low frequency infrasound from Nabro is coincident with high-altitude emissions. Unexpectedly, the eruption also produced hundreds of short-duration, impulsive explosion signals, in addition to the sustained infrasonic jetting signals more typical of subplinian-plinian eruptions. These explosions are variable in amplitude, duration, and often cluster in groups. Here we present: 1) additional analyses, classification, and source estimation of the explosions, 2) infrasound propagation modeling to determine acoustic travel times and propagation paths, 3) detection and characterization of the SO2 emissions using the Ozone Monitoring Instrument (OMI) and Spin Enhanced Visible and Infra-Red Instrument (SEVIRI), and 4) a comparison between the relative infrasound energy and SO2 measurements to investigate the relationship between degassing and infrasound, and to speculate on possible eruption source mechanisms. This example, in addition to other recent work, demonstrates the utility of using regional and global infrasound arrays to characterize explosive volcanic eruptions, particularly in remote and poorly monitored regions. Further, comparison of SO2 emissions and infrasound lends insight into degassing processes and shows the potential to use infrasound as a real-time, remote means to detect hazardous emissions.

Fee, D.; Carn, S. A.; Prata, F.

2011-12-01

341

Retrieval columns of SO2 in industrial chimneys using DOAS passive in traverse  

NASA Astrophysics Data System (ADS)

The optical Differential Optical Absorption Spectroscopy (DOAS) is a technique to measure pollutant emissions like SO2, from point sources and total fluxes in the atmosphere. Passive DOAS systems use sunlight like source. Measurements with such systems can be made in situ and in real time. The goal of this work is to report the implementation of hardware and software of a portable system to evaluate the pollutants emitted in the atmosphere by industrial chimneys. We show SO2 measurements obtained around PEMEX refinerys in Tula Hidalgo that enables the identification of their pollution degree with the knowledge of speed wind.

Galicia Mejía, Rubén; de la Rosa Vázquez, José Manuel; Sosa Iglesias, Gustavo

2011-10-01

342

Mechanism for chelated sulfate formation from SO2 and bis (triphenylphosphine) platinum  

NASA Technical Reports Server (NTRS)

Structure and energy surface calculations using the atom superposition and electron delocalization molecular orbital theory show that the first step in the reaction between SO2 and the dioxygen complex (PPh3)2PtO2 is the coordination of SO2 with one oxygen atom of the complex, followed by metal-oxygen bond breaking and reorientation, leading to a five-membered cyclic structure. This then rearranges to form the bidentate coordinated sulfate. Alternative pathways are considered and are found to be less favorable.

Mehandru, S. P.; Anderson, A. B.

1985-01-01

343

SO2 photolysis as a source for sulfur mass-independent isotope signatures in stratospheric aerosols  

NASA Astrophysics Data System (ADS)

Signatures of sulfur isotope mass-independent fractionation (S-MIF) have been observed in stratospheric sulfate aerosols deposited in polar ice. The S-MIF signatures are associated with stratospheric photochemistry following stratospheric volcanic eruptions, but the exact mechanism responsible for the production and preservation of these signatures is debated. In order to identify the origin and the mechanism of preservation for these signatures, a series of laboratory photochemical experiments were carried out to investigate the effect of temperature and added O2 on S-MIF produced by the two absorption band systems of SO2 photolysis in the 190 to 220 nm region and photoexcitation in the 250 to 350 nm region. The SO2 photolysis (SO2 + h? ? SO + O) experiments showed S-MIF signals with large 34S / 32S fractionation, which increases with decreasing temperature. The overall S-MIF pattern observed for photolysis experiments, including high 34S / 32S fractionations, positive mass-independent anomalies in 33S, and negative anomalies in 36S, is consistent with a major contribution from optical isotopologue screening effects and measurements for stratospheric sulfate aerosols. SO2 photoexicitation produced products with positive MIF anomalies in both 33S and 36S that is different from stratospheric aerosols. SO2 photolysis in the presence of O2 produced SO3 with S-MIF signals, suggesting the transfer of the MIF signals of SO to SO3 by the SO + O2 + M ? SO3 + M reaction. This is supported with energy calculations of stationary points on the SO3 potential energy surfaces, which indicate that this reaction occurs slowly on a single adiabatic surface, but that it can occur more rapidly through intersystem crossing. The results from our experiments constrain the termolecular reaction rate to between 1.0 × 10-37 cm6 molecule-2 s-1 and 1.0 × 10-36 cm6 molecule-2 s-1. This rate can explain the preservation of mass independent isotope signatures in stratospheric sulfate aerosols and provides a minor, but important, oxidation pathway for stratospheric SO2 above about 25 km altitude. The production and preservation of S-MIF signals in the stratosphere requires a high SO2 column density and an SO2 plume reaching an altitude of 25 km and higher.

Whitehill, A. R.; Jiang, B.; Guo, H.; Ono, S.

2014-09-01

344

Atmospheric SO2 Emissions Since the Late 1800s Change Organic  

E-print Network

Atmospheric SO2 Emissions Since the Late 1800s Change Organic Sulfur Forms in Humic Substance-ray near- edge spectroscopy (XANES) on humic substance extracts of archived samples from the Rothamsted ) 0.0024; N ) 11). Presently, the ratio of oxidized- to-reduced organic S in humic substance extracts

Lehmann, Johannes

345

SILICA-ENHANCED SORBENTS FOR DRY INJECTION REMOVAL OF SO2 FROM FLUE GAS (JOURNAL VERSION)  

EPA Science Inventory

The paper gives results of tests of novel silica-enhanced lime sorbents in a bench-scale sand-bed reactor for their potential for SO2 removal from flue gas. Reactor conditions were: 64 C, relative humidity 60% (corresponding to an approach to saturation temperature of 10 C), and ...

346

Degradation behavior of high surface area calcium hydroxide sorbent for SO 2 removal  

Microsoft Academic Search

The degradation behavior of a calcium hydroxide sorbent for SO2 removal was investigated in terms of microstructure and crystal phase change. Hydrated lime sorbents with a high surface area were prepared by hydration of Diethylene glycol-coated quicklime. A durability test for sorbents was carried out in a consistent chamber condition at a temperature of 50°C and a humidity level of

Hyun-Gyoo Shin; Hwan Kim; Taimin Noh; Dowan Kim; Yong-Nam Kim

2011-01-01

347

Removal of NOx and SO2 in flue gas by corona plasma reactor with water film  

Microsoft Academic Search

NOx and SO2 removal methods using plasma chemical reactions in nonthermal plasma have been widely studied. In this paper, a novel type of corona discharge model with water film was designed. The reactor is composed of needle-plate electrodes that are placed in a glass container filled with the flue gas, (the plate electrode is immersed in the water). The influence

Limin Dong; Jiaxiang Yang

2002-01-01

348

ALARM-LEVEL MONITOR FOR SO2 EMISSIONS FROM STATIONARY SOURCES  

EPA Science Inventory

A field prototype, alarm-level monitor for SO2 emissions from stationary sources was designed, fabricated and tested. The monitor was designed to be inexpensive, simple to operate and easily maintained. The monitoring system is an extractive type that employs an air aspirator to ...

349

MECHANISM OF SO2 AND H2SO4 AEROSOL ZINC CORROSION  

EPA Science Inventory

This study established the physical variables controlling the SO2 and H2SO4 induced corrosion of zinc. Relative humidity, temperature, air flow velocity, flow turbulence, aerosol size range, and pollutant concentration were controlled. Corrosion measurements were made through the...

350

CALCINATION OF CALCIUM-BASED SORBENTS FOR CONTROL OF SO2 EMISSIONS FROM COAL FIRED BOILERS  

EPA Science Inventory

The paper summarizes the results of an experimental study that focused on the production of high surface area materials from various sorbents. (NOTE: Injecting calcium-based sorbents into coal burning utility boilers to control SO2 emissions is being considered by the EPA as an a...

351

THE SO2 ALLOWANCE TRADING SYSTEM: THE IRONIC HISTORY OF A GRAND POLICY EXPERIMENT  

E-print Network

to curb acid rain, the government did the right thing for the wrong reason. Second, a substantial source-based instruments, cap-and-trade, Clean Air Act amendments of 1990, sulfur dioxide, acid rain JEL Classification that acid precipitation ­ the result of sulfur dioxide (SO2) and, to a lesser extent, nitrogen oxides (NOx

Ford, Andrew

352

ESTIMATING PERFORMANCE AND COSTS OF RETROFIT SO2 AND NOX CONTROLS FOR ACID RAIN ABATEMENT  

EPA Science Inventory

The paper gives results from an ongoing National Acid Precipitation Assessment Program (NAPAP) to significantly improve engineering cost estimates currently being used to evaluate the economic effects of applying SO2 and NOx controls to existing coal-fired utility boilers. Initia...

353

FUNDAMENTAL STUDIES OF CALCIUM-BASED SORBENTS FOR SO2 CONTROL FROM COAL-FIRED BOILERS  

EPA Science Inventory

The report gives results of laboratory-scale controlled-temperature experiments, studying aspects of SO2 capture by calcium-based sorbents in a flame/gas environment. Experimental parameters were sorbent type, temperature, residence time, and effects of mineral additives (promote...

354

PERFORMANCE EVALUATION OF AN INDUSTRIAL SPRAY DRYER FOR SO2 CONTROL  

EPA Science Inventory

The report gives results of a test to evaluate the SO2 removal performance of the lime-spray-dryer/fabric-filter system treating flue gas from the stoker-coal-fired boiler at Celanese's Amcelle plant in Cumberland, MD, in August/September 1980. Continuous monitors were used to co...

355

SHELL NOX/SO2 FLUE GAS TREATMENT PROCESS: PILOT PLANT EVALUATION  

EPA Science Inventory

The report gives results of an evaluation of the Shell Flue Gas Treatment process in a pilot-scale test for simultaneously reducing the emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) from flue gas produced in a coal-fired utility boiler. Flue gas leaving the economiz...

356

HUMIDIFICATION OF FLUE GAS TO AUGMENT SO2 CAPTURE BY DRY SORBENTS  

EPA Science Inventory

The report discusses, for a coal-burning power plant, using humidification of the flue gas in a low-temperature duct to increase SO2 removal by dry calcium-based sorbents. In particular, humidification may be a desirable modification of EPA's LIMB process, which is based on injec...

357

Adsorption of O2, SO2, and SO3 on nickel oxide. Mechanism for sulfate formation  

NASA Technical Reports Server (NTRS)

Calculations based on the atom superposition and electron delocalization molecular orbital (ASED-MO) technique suggest that O2 will adsorb perferentially end-on at an angle 45 deg from normal on a nickel cation site on the (100) surface of NiO. SO2 adsorption is also stronger on the nickel site; SO2 bonds through the sulfur atom is a plane perpendicular to the surface. Adsorption energies for SO3 on the nickel and oxygen sites are comparable in the perferred orientation in which the SO3 plane is parallel to the surface. On activation, SO3 adsorbed to an O2(-) site forms a trigonal pyramidal SO4 species which yields, with a low barrier, a tetrahedral sulfate anion. Subsequently the anion reorients on the surface. Possibilities for alternative mechanisms which require the formation of Ni3(+) or O2(-) are discussed. NiSO4 thus formed leads to the corrosion of Ni at high temperatures in the SO2+O2/SO3 The SO2+O2/SO3 atmosphere, as discussed in the experimental literature.

Mehandru, S. P.; Anderson, A. B.

1985-01-01

358

DEPOSITION VELOCITIES OF SO2 AND O3 OVER AGRICULTURAL AND FOREST ECOSYSTEMS  

EPA Science Inventory

The results of field studies that measured the flux and deposition velocity of SO2 and O3 are reported. Three of the studies were over agricultural crops (pasture, corn, and soybean), and two were over forest (a deciduous forest and a mixed coniferous - deciduous forest). In al...

359

SO2 emissions to the atmosphere from active volcanoes in Guatemala and El Salvador, 19992002  

E-print Network

SO2 emissions to the atmosphere from active volcanoes in Guatemala and El Salvador, 1999 INSIVUMEH, 7a Avenida 14-57 Zona 13, Ciudad de Guatemala, Guatemala, Central America c Servicio Nacional de-based and aircraft correlation spectrometer (COSPEC) measurements at the principal active volcanoes in Guatemala

Rose, William I.

360

Parametrization of electron impact ionization cross sections for CO, CO2, NH3 and SO2  

NASA Technical Reports Server (NTRS)

The electron impact ionization and dissociative ionization cross section data of CO, CO2, CH4, NH3, and SO2, measured in the laboratory, were parameterized utilizing an empirical formula based on the Born approximation. For this purpose an chi squared minimization technique was employed which provided an excellent fit to the experimental data.

Srivastava, Santosh K.; Nguyen, Hung P.

1987-01-01

361

SILICA-ENHANCED SORBENTS FOR DRY INJECTION REMOVAL OF SO2 FROM FLUE GAS  

EPA Science Inventory

The paper gives results of tests of novel silica-enhanced lime sorbents in a bench-scale sand-bed reactor for their potential for SO2 removal from flue gas. Reactor conditions were: 64 C, relative humidity 60% (corresponding to an approach to saturation temperature of 10C), and i...

362

TRANSFERABLE DISCHARGE PERMITS FOR CONTROL OF SO2 EMISSIONS FROM ILLINOIS POWER PLANTS (JOURNAL VERSION)  

EPA Science Inventory

The paper discusses the use of a large scale simulation model in evaluating various policy alternatives for reducing SO2 emissions from Illinois electric power plants for a broad range of nuclear power capacity addition scenarios. A dynamic simulation of a transferable discharge ...

363

SO2 over central China: Measurements, numerical simulations and the tropospheric sulfur budget  

E-print Network

concentrations decreased from $7 ppbv near the surface to $1 ppbv at 1800 m altitude (an effective scale height of $800 m), but distinct SO2 plumes were observed between 1800 and 4500 m, the aircraft's ceiling], cause visibility impairments [Hand and Malm, 2007], and pose a hazard to public health [U

Dickerson, Russell R.

364

PROCEEDINGS: 1990 SO2 CONTROL SYMPOSIUM - VOLUME 3: SESSIONS 6A, 6B, 6C  

EPA Science Inventory

The proceedings document 110 papers presented at the Symposium held in New Orleans, LA, May 8-11, 1990. opics included SO2 control economics, furnace sorbent injection, byproduct utilization, spray dryer technology, wet flue gas desulfurization (FGD) and combined SOx/NOx control ...

365

PROCEEDINGS: 1990 SO2 CONTROL SYMPOSIUM - VOLUME 1: SESSIONS 1, 2, 3A, AND 3B  

EPA Science Inventory

The proceedings document 110 papers presented at the Symposium held in New Orleans, LA, May 8-11, 1990. opics included SO2 control economics, furnace sorbent injection, byproduct utilization, spray dryer technology, wet flue gas desulfurization (FGD) and combined SOx/NOx control ...

366

PROCEEDINGS: 1990 SO2 CONTROL SYMPOSIUM - VOLUME 4: SESSIONS 7A, 7B, AND POSTERS  

EPA Science Inventory

The proceedings document 110 papers presented at the Symposium held in New Orleans, LA, May 8-11, 1990. opics included SO2 control economics, furnace sorbent injection, byproduct utilization, spray dryer technology, wet flue gas desulfurization (FGD) and combined SOx/NOx control ...

367

Mid-Infrared Detection of Large Longitudinal Asymmetries in Io's SO2 Atmosphere  

E-print Network

1 Mid-Infrared Detection of Large Longitudinal Asymmetries in Io's SO2 Atmosphere John R. Spencer1 13th 2005 Accepted, January 28th 2004 Keywords: Io; Atmospheres, Structure; Infrared Observations. These are the first ground-based infrared observations of Io's sunlit atmosphere, and provide a new window

Spencer, John

368

CARTANDECOMPOSITION SUBGROUPS OF SO(2; n) HEE OH AND DAVE WITTE  

E-print Network

CARTAN­DECOMPOSITION SUBGROUPS OF SO(2; n) HEE OH AND DAVE WITTE Abstract. For G = SL(3; R) and G). 1 #12; 2 HEE OH AND DAVE WITTE 1.4. Proposition (Calabi­Markus phenomenon, cf. [Kul, pf. of Thm. A.1

Bielefeld, University of

369

EVALUATION OF SOLIDS DEWATERING FOR A PILOT-SCALE THIOSORBIC LIME SO2 SCRUBBER  

EPA Science Inventory

The paper gives results of an evaluation of solids dewatering for a pilot-scale thiosorbic lime SO2 scrubber. Pilot plant data showed that the dissolved magnesium in thiosorbic lime caused deterioration of solids dewatering properties. The slurry settling rate increased when the ...

370

Interaction of SO2 and CO with the Ti2O3(101¯2) surface  

NASA Astrophysics Data System (ADS)

The interaction of sulfur dioxide with the nearly perfect (101¯2) surface of the corundum transition-metal oxide Ti2O3 has been studied using ultraviolet and x-ray photoemission spectroscopies and low-energy electron diffraction. The reaction of SO2 with Ti2O3 is found to be extremely vigorous, with SO2 adsorbing dissociatively and catalyzing the complete oxidation of the surface to TiO2 and TiS2. This result is significant since exposure to large amounts of O2 does not result in the production of large amounts of TiO2 at the Ti2O3 surface. Dissociative adsorption of SO2 continues for exposures up to at least 104 L (1 L=10-6Torr sec). The reaction is accompanied by large scale surface disorder and by an increase in the work function of 1.32 eV. In contrast, CO adsorbs molecularly for exposures >=105 L, with an extramolecular relaxation-polarization shift of 3.0 eV. For CO exposures <=104 L, the chemisorption mechanism is tentatively identified as dissociative adsorption at defect sites. Inclusive of this study, the interaction of four oxygen-containing molecules (SO2, CO, H2O, and O2) with Ti2O3(101¯2) surfaces has been studied, and their behavior is compared and trends isolated with a view to understanding the oxidation of Ti2O3.

Smith, Kevin E.; Henrich, Victor E.

1985-10-01

371

CO2 greenhouse in the early martian atmosphere: SO2 inhibits condensation  

NASA Technical Reports Server (NTRS)

Many investigators of the early martian climate have suggested that a dense carbon dioxide atmosphere was present and warmed the surface above the melting point of water (J.B. Pollack, J.F. Kasting, S.M. Richardson, and K. Poliakoff 1987. Icarus 71, 203-224). However, J.F. Kasting (1991. Icarus 94, 1-13) pointed out that previous thermal models of the primitive martian atmosphere had not considered the condensation of CO2. When this effect was incorporated, Kasting found that CO2 by itself is inadequate to warm the surface. SO2 absorbs strongly in the near UV region of the solar spectrum. While a small amount of SO2 may have a negligible effect by itself on the surface temperature, it may have significantly warmed the middle atmosphere of early Mars, much as ozone warms the terrestrial stratosphere today. If this region is kept warm enough to inhibit the condensation of CO2, then CO2 remains a viable greenhouse gas. Our preliminary radiative modeling shows that the addition of 0.1 ppmv of SO2 in a 2 bar CO2 atmosphere raises the temperature of the middle atmosphere by approximately 10 degrees, so that the upper atmosphere in a 1 D model remains above the condensation temperature of CO2. In addition, this amount of SO2 in the atmosphere provides an effective UV shield for a hypothetical biosphere on the martian surface.

Yung, Y. L.; Nair, H.; Gerstell, M. F.

1997-01-01

372

First Observations of SO2 from the Satellite Suomi NPP OMPS: Widespread Air Pollution Events over  

E-print Network

First Observations of SO2 from the Satellite Suomi NPP OMPS: Widespread Air Pollution Events over;Severe smog episodes over China in January 2013 received worldwide at- tention. This air pollution. The largest sources of air pollutants in China are coal combustion and motor vehicle exhausts [He et al., 2002

Dickerson, Russell R.

373

Plasma Modification of Activated Carbon Fibers for Adsorption of SO2  

NASA Astrophysics Data System (ADS)

Viscose-based activated carbon fibers (VACFs) were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasma-treated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.

Che, Yao; Zhou, Jiayong; Wang, Zuwu

2013-10-01

374

The influence of fuel additives SO2E on diesel engine exhaust emission  

Microsoft Academic Search

One of the methods that allows substantially to reduce exhaust smoke of diesel engines and avoid possible damage of the environment by harmful emissions is the usage of multipurpose fuel additives. The efficiency of new Estonian made fuel additives SO-2E, that have been introduced recently for the experts attention, was investigated in small heating boilers and low-powered ships. The purpose

Gvidonas Labeckas; Stasys Slavinskas

2003-01-01

375

AEROSOL FORMATION FROM DIESEL EXHAUST AND SO2. A CHAMBER STUDY  

EPA Science Inventory

Dilute diesel emission systems were studied in a 600 cu m indoor smog chamber under various conditions likely to be encountered in an urban environment. Aerosol formation and growth in an irradiated diesel emission/SO2/propylene system was primarily attributed to sulfate formatio...

376

Tutorial on OpenFlow So2ware-defined networking  

E-print Network

· Team working on OpenFlow/SDN: ­ Elio Salvadori (Area Head) ­ Roberto Doriguzzi12/20/11 1 Tutorial on OpenFlow and So2ware-defined networking Elio Salvadori Stanford and OFELIA teams Outline · Who are we? · What is OpenFlow · How OpenFlow

Lo Cigno, Renato Antonio

377

The Atmospheric Sulphur Cycle and the Role of Volcanic SO2  

E-print Network

studies of tropospheric ozone, methane and secondary aerosol formation, from a variety of climate change as a sulphur scheme that includes dimethyl sulphide (DMS) in addition to SO2 and its gas- and aqueous to the surface, and through oxidation to sulphate aerosol, predominantly in the aqueous phase. Deposition

378

SORBENT/UREA SLURRY INJECTION FOR SIMULTANEOUS SO2/NOX REMOVAL  

EPA Science Inventory

The paper discusses an investigation of the combination of sorbent injection and selective non-catalytic reduction (SNCR) technologies for simultaneous SO2/NOx removal. A slurry of a urea-based solution band various Ca-based sorbents was injected at a range of temperatures and re...

379

ASSESSMENT OF SO2 AND NOX EMISSION CONTROL TECHNOLOGY IN EUROPE  

EPA Science Inventory

The report is a compilation of information on the current status of abatement technology used to control major air pollutants, including SO2 and NOx, in Europe. It focuses on flue gas sulfurization (FGD), combustion modification (CM), and selective catalytic reduction (SCR) of NO...

380

Removal of SO2 from gas streams using a dielectric barrier discharge and combined plasma photolysis  

E-print Network

Removal of SO2 from gas streams using a dielectric barrier discharge and combined plasma photolysis H. Balbach University of Illinois. Department of Electrical and Computer Engineering, 1406 W Green Engineering, I406 F! Green Street, Urbana, Illinois 61801 (Received 8 November 1990; accepted for publication

Kushner, Mark

381

Absorption and desorption of SO2 in aqueous solutions of diamine-based molten salts.  

PubMed

SO2 absorption and desorption behaviors were investigated in aqueous solutions of diamine-derived molten salts with a tertiary amine group on the cation and a chloride anion, including butyl-(2-dimethylaminoethyl)-dimethylammonium chloride ([BTMEDA]Cl, pKb=8.2), 1-butyl-1,4-dimethylpiperazinium chloride ([BDMP]Cl, pKb=9.8), and 1-butyl-4-aza-1-azoniabicyclo[2,2,2]octane chloride ([BDABCO]Cl, pKb=11.1). The SO2 absorption and desorption performance of the molten salt were greatly affected by the basicity of the molten salt. Spectroscopic, X-ray crystallographic, and computational results for the interactions of SO2 with molten salts suggest that two types of SO2-containg species could be generated depending on the basicity of the unquaternized amino group: a dicationic species comprising two different anions, HSO3(-) and Cl(-), and a monocationic species bearing Cl(-) interacting with neutral H2SO3. PMID:25706692

Lim, Seung Rok; Hwang, Junhyeok; Kim, Chang Soo; Park, Ho Seok; Cheong, Minserk; Kim, Hoon Sik; Lee, Hyunjoo

2015-05-30

382

WALL-FIRED BOILER DESIGN CRITERIA FOR DRY SORBENT SO2 CONTROL WITH LOW NOX BURNERS  

EPA Science Inventory

The report assesses the impact of Limestone Injection Multistage Burner (LIMB) technology on wall-fired utility boilers for both new and retrofit designs. Recent attention has focused on dry sorbent sulfur dioxide (SO2) control technology which, in conjunction with low-nitrogen-o...

383

REACTIVITY STUDY OF SO2 CONTROL WITH ATMOSPHERIC AND PRESSURE HYDRATED SORBENTS  

EPA Science Inventory

The report gives results of a study to develop an understanding of the factors that control the reactivity of hydrated sorbents toward SO2 in coal fired furnaces. It focused on the impacts of hydrate properties (e.g., particle size, surface area, and chemical composition) and the...

384

SO2 CONCENTRATION ESTIMATES FOR NEW YORK CITY, 1880-1980  

EPA Science Inventory

The purpose of this investigation was to estimate the yearly ambient concentration of SO2 and SO4 wet deposition from 1880 to 1980 for the greater New York City area. This information was used to reconstruct ambient concentrations at two New York Veterans Administration cemeterie...

385

Sulfur Dioxide (SO2) Primary NAAQS Review: Integrated Review Plan - Advisory with CASAC  

EPA Science Inventory

The SO2 Integrated Review Plan is the first document generated as part of the National Ambient Air Quality Standards (NAAQS) review process. The Plan presents background information, the schedule for the review, the process to be used in conducting the review, and the key policy-...

386

ACTIVATION AND REACTIVITY OF NOVEL CALCIUM-BASED SORBENTS FOR DRY SO2 CONTROL IN BOILERS  

EPA Science Inventory

Chemically modified calcium hydroxide (Ca(OH)2) sorbents developed in the U.S. Environmental Protection Agency's Air and Energy Engineering Research Laboratory (AEERL) for sulfur dioxide (SO2) control in utility boilers were tested in an electrically heated, bench-scale isotherma...

387

FUNDAMENTAL PROCESSES INVOLVED IN SO2 CAPTURE BY CALCIUM-BASED ADSORBENTS  

EPA Science Inventory

The paper discusses the fundamental processes in sulfur dioxide (SO2) capture by calcium-based adsorbents for upper furnace, duct, and electrostatic precipitator (ESP) reaction sites. It examines the reactions in light of controlling mechanisms, effect of sorbent physical propert...

388

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 4. SESSIONS 7, 8A, AND 8B  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

389

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 1. SESSIONS 1, 2, 3A, AND 3B  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

390

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 2. SESSIONS 4A, 4B, AND 5A  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

391

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 2. SESSIONS 1-3  

EPA Science Inventory

The proceedings document the 1991 SO2 Control Symposium, held December 3-6, 1991, in Washington, DC, and jointly sponsored by the Electric Power Research Institute (EPRI), the U. S. Environmental Protection Agency (EPA), and the U.S. Department of Energy (DOE). he symposium focus...

392

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 3. SESSIONS 5B AND 6  

EPA Science Inventory

The proceedings document the 1991 SO2 Control Symposium, held December 3-6, 1991, in Washington, DC, and jointly sponsored by the Electric Power Research Institute (EPRI), the U. S. Environmental Protection Agency (EPA), and the U.S. Department of Energy (DOE). he symposium focus...

393

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 3. SESSIONS 5B, 6A, AND 6B  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

394

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 1. OPENING SESSION AND SESSIONS 1-3  

EPA Science Inventory

The proceedings document the 1991 SO2 Control Symposium, held December 3-6, 1991, in Washington, DC, and jointly sponsored by the Electric Power Research Institute (EPRI), the U. S. Environmental Protection Agency (EPA), and the U.S. Department of Energy (DOE). he symposium focus...

395

40 CFR 60.43 - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2014 CFR

... Standards of Performance for Fossil-Fuel-Fired Steam Generators § 60.43 Standard for sulfur dioxide (SO2 ...and 2 (as defined in appendix G of this part) at the Newton Power Station owned or operated by the Central Illinois...

2014-07-01

396

40 CFR 60.43 - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2012 CFR

... Standards of Performance for Fossil-Fuel-Fired Steam Generators § 60.43 Standard for sulfur dioxide (SO2). ...and 2 (as defined in appendix G of this part) at the Newton Power Station owned or operated by the Central Illinois...

2012-07-01

397

40 CFR 60.43 - Standard for sulfur dioxide (SO2).  

Code of Federal Regulations, 2013 CFR

... Standards of Performance for Fossil-Fuel-Fired Steam Generators § 60.43 Standard for sulfur dioxide (SO2 ...and 2 (as defined in appendix G of this part) at the Newton Power Station owned or operated by the Central Illinois...

2013-07-01

398

CO2-SO2 clathrate hydrate formation on early Mars1 Eric Chassefirea,b  

E-print Network

1 CO2-SO2 clathrate hydrate formation on early Mars1 2 Eric Chassefièrea,b , Emmanuel Dartoisc hal-00804822,version1-26Mar2013 Author manuscript, published in "Icarus 223, 2 (2013) 878-891" DOI atmosphere was necessary in order to keep28 early Mars warm and wet. However, current models have not been

Boyer, Edmond

399

Adsorption of O2, SO2, and SO3, on nickel oxide - Mechanism for sulfate formation  

NASA Technical Reports Server (NTRS)

Calculations based on the atom superposition and electron delocalization molecular orbital technique suggest that O2 will adsorb preferentially end-on at an angle 45 deg from normal on a nickel cation site on the (100) surface of NiO. SO2 adsorption is also stronger on the nickel site; SO2 bonds through the sulfur atom in a plane perpendicular to the surface. Adsorption energies for SO3 on the nickel and oxygen sites are comparable in the preferred orientation in which the SO3 plane is parallel to the surface. The calculations suggest that the strength of adsorption varies as O2 greater than SO2 greater than SO3. On activation, SO3 adsorbed to an O(2-) site forms a trigonal pyramidal SO4 species which yields, with a low barrier, a tetrahedral sulfate anion. Subsequently the anion reorients on the surface. Alternative mechanisms which require the formation of Ni(3+) or O(-) are discussed. NiSO4 thus formed may play a passivating role for the corrosion of Ni at low temperatures in the SO2 + O2 + SO3 atmospheres and an active role at high temperatures, as discussed in the experimental literature.

Mehandru, S. P.; Anderson, A. B.

1986-01-01

400

INFLUENCE OF COAL MINERAL MATTER ON THE EFFECTIVENESS OF DRY SORBENT INJECTION FOR SO2 CONTROL  

EPA Science Inventory

The report describes the use of laboratory-, bench-, and pilot-scale facilities to examine the impact of mineral matter on calcium-based sorbent reactivity toward SO2. Two areas of concern were investigated: (1) deleterious effects of coal ash; and, (2) beneficial (promoter) effe...

401

CARTAN-DECOMPOSITION SUBGROUPS OF SO(2, n) HEE OH AND DAVE WITTE  

E-print Network

CARTAN-DECOMPOSITION SUBGROUPS OF SO(2, n) HEE OH AND DAVE WITTE Abstract. For G = SL(3, R) and G a Cartan decomposition G = KA+ K of G, and then carry out an approximate calculation of (KHK) A+ for each(2, n). Fix an Iwasawa decomposition G = KAN and a corresponding Cartan decomposition G = KA+K, where

Oh, Hee

402

IDENTIFICATION OF CASO4 FORMED BY REACTION OF CAO AND SO2  

EPA Science Inventory

The injection of calcium-based sorbents into coal-fired boilers for reaction with, and reduction in the levels of, sulfur dioxide (SO2) in the flue gas has undergone considerable research and development. Significant effort has also been made in developing models for the overall ...

403

40 CFR 60.4330 - What emission limits must I meet for sulfur dioxide (SO2)?  

Code of Federal Regulations, 2010 CFR

...of Performance for Stationary Combustion Turbines Emission Limits § 60.4330 What...sulfur dioxide (SO2)? (a) If your turbine is located in a continental area, you...or (a)(3) of this section. If your turbine is located in Alaska, you do not...

2010-07-01

404

Formation of sulfite-like species on Cr 2O 3 after SO 2 chemisorption  

NASA Astrophysics Data System (ADS)

The adsorption of sulfur dioxide (SO 2) on polycrystalline Cr 2O was experimentally investigated using temperature-programmed desorption (TPD). The chemisorption of SO 2 on the (0001) surface was also studied using theoretical methods. Different adsorption geometries were explored for SO 2 adsorption on the ?-Cr 2O (0001) surface. Two similar adsorption configurations were found to be the most stable with chemisorption energies of - 3.09 and - 2.79 eV/molecule. In both calculated stable adsorption configurations the appearance of sulfite-like species is predicted on the (0001) surface after adsorption. It is important to emphasize that these results are predicted only within the DFT + U framework. Under these conditions and despite great efforts, no stable sulfate-like geometry was found on this surface. The TPD spectrum exhibit a desorption peak at Tp ? 870 °C with a heating rate of ? ? 0.12 °C/s. The desorption energy calculated by the analysis given by Redhead and Adams, assuming the rate of desorption is given by a Polanyi-Wigner equation, is ? - 3.12 eV. This value is in good agreement with the predicted one using DFT + U calculations. To our knowledge, this is the first theoretical study of SO 2 adsorption on the Cr 2O (0001) surface.

Ranea, V. A.; Hernandez, S. N.; Medina, S.; Irurzun, I. M.; Coria, I. D.; Mola, E. E.

2011-03-01

405

ALTERNATIVES TO CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: CONCEPTUAL EVALUATION  

EPA Science Inventory

The report gives results of a conceptual engineering evaluation to screen supported metal oxides as alternatives to natural calcium-based sorbents (limestones and dolomites) for SO2 control in atmospheric and pressurized fluidized-bed combustion (FBC) processes. Alternative sorbe...

406

Simultaneous retrieval of volcanic ash and SO2 using MSG-SEVIRI measurements  

Microsoft Academic Search

Volcanic ash and sulphur dioxide masses from the November 2005 eruption of Karthala volcano, Comoros Islands, are simultaneously retrieved using rapid-scan, multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite. Retrievals are made every 15 min, which show that the ash and SO2 separate in the vertically sheared atmosphere producing

A. J. Prata; J. Kerkmann

2007-01-01

407

SHELL NOX/SO2 FLUE GAS TREATMENT PROCESS: INDEPENDENT EVALUATION  

EPA Science Inventory

The report gives results of an independent evaluation of the Shell Flue Gas Treatment (SFGT) process which simultaneously reduces nitrogen oxide (NOx) and sulfur dioxide (SO2) emissions. NOx emissions from stationary sources may be reduced by 80-90 percent by applying selective c...

408

Predicting SO2 pollution incidents by means of additive models with optimum variable selection  

NASA Astrophysics Data System (ADS)

The aim of this paper is to predict time series of SO2 concentrations emitted by coal-fired power stations in order to estimate in advance emission episodes and analyze the influence of some meteorological variables in the prediction. An emission episode is said to occur when the series of bi-hourly means of SO2 is greater than a specific level. For coal-fired power stations it is essential to predict emission episodes sufficiently in advance so appropriate preventive measures can be taken. We proposed a methodology to predict SO2 emission episodes based on using an additive model and an algorithm for variable selection. The methodology was applied to the estimation of SO2 emissions registered in sampling locations near a coal-fired power station located in Northern Spain. The results obtained indicate a good performance of the model considering only two terms of the time series and that the inclusion of the meteorological variables in the model is not significant.

Sestelo, Marta; Roca-Pardiñas, Javier; Ordóñez, Celestino

2014-10-01

409

SO2 Emission from Active Volcanoes Measured Simultaneously by COSPEC and mini-DOAS  

NASA Astrophysics Data System (ADS)

We measured SO2 emission rate from six volcanoes in Latin America (Santa Ana, El Salvador; San Cristóbal and Masaya, Nicaragua; Arenal and Poás, Costa Rica; Tungurahua and Sierra Negra, Ecuador) and from Mt. Etna, Italy, using two different remote sensing techniques: COSPEC (COrrelation SPECtrometer) and miniDOAS (miniaturized Differential Optical Absorption Spectroscopy). One of the goals of this study was to evaluate the differences in SO2 emission rates obtained by these two methods. The observed average SO2 emission rates measured during this study were 2688 t· d -1 from Tungurahua in July 2006, 2375 t· d -1 in September 2005 and 480 t· d -1 in February 2006 from Santa Ana, 1200 t· d -1 in May 2005 from Etna, 955 t· d -1 in March 2006 and 1165 t· d -1 in December 2006 from Masaya, 5400 t· d -1 of March 7, 2006 and 265 t· d -1 in March 2006 from San Cristobal, 113 t· d -1 in April 2006 from Arenal, 104 t· d -1 in April 2006 from Poás and 11 t· d -1 in July 2006 from Sierra Negra volcano. Most of the observed relative differences of SO2 emission measurements from COSPEC and miniDOAS were lower than 10%.

Barrancos, José; Roselló, José I.; Calvo, David; Padrón, Eleazar; Melián, Gladys; Hernández, Pedro A.; Pérez, Nemesio M.; Millán, Millán M.; Galle, Bo

2008-01-01

410

Regional climate responses to geoengineering with tropical and Arctic SO2 injections  

E-print Network

Regional climate responses to geoengineering with tropical and Arctic SO2 injections Alan Robock,1 insolation and cool Earth, has been suggested as an emergency response to geoengineer the planet in response aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone

Robock, Alan

411

CONCENTRATION STATISTICS BY WIND DIRECTION FOR 1976 ST. LOUIS SO2 MEASUREMENTS AND MODEL ESTIMATES  

EPA Science Inventory

In a previous evaluation of the urban air quality simulation model RAM using hourly SO2 concentrations measured in 1976 at 13 sites during the Regional Air Pollution Study conducted in St. Louis, Missouri, bias with stability was noted. A speculated cause of maxima from the model...

412

EFFECT OF SPECIFIC SURFACE AREA ON THE REACTIVITY OF CAO WITH SO2  

EPA Science Inventory

The paper discusses results of measuring the rate of reaction of calcined limestone (CaCO3) with sulfur dioxide (SO2) and oxygen (O2) at conditions that eliminate all resistances not associated with the lime (CaO) grain surface. Reactivity increased with the square of the Brunaue...

413

UNIVERSITY OF WASHINGTON ELECTROSTATIC SCRUBBER TESTS: COMBINED PARTICULATE AND SO2 CONTROL  

EPA Science Inventory

The report gives results of tests of a 1700 a cu m/hr University of Washington electrostatic spray scrubber pilot plant on a coal-fired boiler to demonstrate its effectiveness for controlling fine particle and SO2 emissions. The multiple-pass portable pilot plant operates by comb...

414

PROCEEDINGS: FIRST COMBINED FGD AND DRY SO2 CONTROL SYMPOSIUM. VOLUME 2. SESSIONS 5 AND 6  

EPA Science Inventory

The proceedings document presentations at the First Combined FGD and Dry SO2 Control Symposium, in St. Louis, MO, October 25-28, 1988. The symposium, jointly sponsored by EPA and EPRI, had as its objective the exchange of technical and regulatory information on sulfur oxide contr...

415

PROCEEDINGS: FIRST COMBINED FGD AND DRY SO2 CONTROL SYMPOSIUM. VOLUME 3. SESSIONS 7 AND 8  

EPA Science Inventory

The proceedings document presentations at the First Combined FGD and Dry SO2 Control Symposium, in St. Louis, MO, October 25-28, 1988. The symposium, jointly sponsored by EPA and EPRI, had as its objective the exchange of technical and regulatory information on sulfur oxide contr...

416

Optical characterization of UV multispectral imaging cameras for SO2 plume measurements  

NASA Astrophysics Data System (ADS)

Only a few years ago spectral imaging cameras for SO2 plume monitoring were developed for remote sensing of volcanic plumes. We describe the development from a first camera using a single filter in the absorption band of SO2 to more advanced systems using several filters and an integrated spectrometer. The first system was based on the Hamamatsu C8484 UV camera (1344 x 1024 pixels) with high quantum efficiency in the UV region from 280 nm onward. At the heart of the second UV camera system, EnviCam, is a cooled Alta U47 camera, equipped with two on-band (310 and 315 nm) and two off-band (325 and 330 nm) filters. The third system utilizes again the uncooled Hamamatsu camera for faster sampling (~10 Hz) and a four-position filter-wheel equipped with two 10 nm filters centered at 310 and 330 nm, a UV broadband view and a blackened plate for dark-current measurement. Both cameras have been tested with lenses with different focal lengths. A co-aligned spectrometer provides a ~0.3nm resolution spectrum within the field-of-view of the camera. We describe the ground-based imaging cameras systems developed and utilized at our Institute. Custom made cylindrical quartz calibration cells with 50 mm diameter, to cover the entire field of view of the camera optics, are filled with various amounts of gaseous SO2 (typically between 100 and 1500 ppm•m). They are used for calibration and characterization of the cameras in the laboratory. We report about the procedures for monitoring and analyzing SO2 path-concentration and fluxes. This includes a comparison of the calibration in the atmosphere using the SO2 cells versus the SO2 retrieval from the integrated spectrometer. The first UV cameras have been used to monitor ship emissions (Ny-Ålesund, Svalbard and Genova, Italy). The second generation of cameras were first tested for industrial stack monitoring during a field campaign close to the Rovinari (Romania) power plant in September 2010, revealing very high SO2 emissions (> 1000 ppm•m). The second generation cameras are now used by students from several universities in Romania. The newest system has been tested for volcanic plume monitoring at Turrialba, Costa Rica in January, 2011, at Merapi volcani, Indonesia in February 2011, at Lascar volcano in Chile in July 2011 and at Etna/Stromboli (Italy) in November 2011. Retrievals from some of these campaigns will be presented.

Stebel, K.; Prata, F.; Dauge, F.; Durant, A.; Amigo, A.,

2012-04-01

417

Low to negligible BrO/SO2 ratios at two subduction-zone volcanoes  

NASA Astrophysics Data System (ADS)

In July 2013 a measurement campaign took place on Kyushu, Japan, investigating the BrO/SO2 ratio in the plume of Sakurajima and Aso. Multi-Axis-Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were carried out at four sides on Sakurajima Island, with a maximum distance of about 5 km downwind, and assuming a wind speed of 5 m/s (corresponding to a plume age of about 15 minutes). At Aso measurements took place on the western slope of the active crater and at the crater rim. The MAX-DOAS data of both sites were evaluated for BrO and SO2 slant column densities (SCDs). In the following, BrO/SO2 ratios were calculated to overcome dilution effects and to investigate the BrO formation processes in the ash-laden plume of Sakurajima and the volcanic plume of Aso which is characterized by emissions from a fumarolic area and a mud pool. The BrO/SO2 ratios of the measurement have been below the detection limit for Aso as well as during most of the measurement days at Sakurajima with the only exception on 15th July 2013, when a BrO/SO2 ratio of ~ 1 x 10-5 could be determined. After very high BrO/SO2 ratios at Sakurajima that were reported by C. Lee et al. (2005) our results seem to be unexpected but nevertheless match the general geological settings at both volcanoes. In a recent paper, Shinohara (2013) summarized and compared chlorine emissions from the Japanese volcanic arc with global chlorine emissions from arc volcanoes and pointed out that the volcanic gas emissions in Japan are quite Cl-poor compared to those at other subduction zones. In the recent past it has been found that low chlorine emissions can occur together with nevertheless high bromine emissions (Nyiragongo, Bobrowski et al., 2013). However, looking up Br/Cl ratios (of condensate measurements at fumaroles) of the Japanese arc volcanism summarized in Gerlach, 2004 a comparatively low Br/Cl ratio is added with 6-7 x 10-4 (global arc mean 2 x 10-3) to the already poor chlorine emissions. We will present upper limits of BrO/SO2 ratios and give an estimate on bromine emissions of Aso and Sakurajima for July 2013. To our knowledge these are the so far lowest bromine emission from an arc volcano. Possible reasons will be discussed in the light of today's available literature - pointing out the geological particularities on Eurasian-Philippine plate subduction zone.

Bobrowski, Nicole; Hörmann, Christoph; Mori, Toshiya; Platt, Ulrich

2014-05-01

418

SO2 emissions from persistently active explosive volcanoes: can we estimate their contribution using satellite instruments?  

NASA Astrophysics Data System (ADS)

The scientific community has long since recognized the importance of sulfur dioxide (SO2) on climate change. The most universally accepted theory is that large amounts of SO2 injected into the atmosphere will react to form sulfate aerosols that reflect sunlight, thereby decreasing global temperature. This cooling effect has been observed after large eruptions throughout the geologic and historic records. The exact effect of SO2 on global climate though is still poorly understood. Estimates of global volcanic SO2 emissions rely primarily on two sets of data: ground-based measurements of SO2 fluxes using COSPEC or DOAS and more recently satellite observations. Both of these usually represent ‘snapshots’ of the gas emissions and at only a few places is continuous monitoring and data acquisition possible. Because continuous data are so rare, many assumptions have to be made when trying to estimate the global volcanic SO2 input to the atmosphere. This is especially true when it comes to frequently exploding volcanoes. Most of their background activity is very low in intensity or the gas plume may simply not reach the stratosphere, both of which make it impossible for satellite instruments to detect it. On the other hand, while individual explosions produce plumes big enough to be detected by satellite instruments, they are often not captured from the ground because no continuous monitoring is in place. Therefore neither satellite nor ground-based data fully represents the total SO2 emissions of these volcanoes. We have analyzed satellite data for several persistently active explosive volcanic centers in an attempt to determine whether their SO2 emissions are detectable and to what extent we can quantify them. We used data from the Ozone Monitoring Instrument (OMI), which operates in the UV spectrum, the Moderate Resolution Imaging Spectroradiometer (MODIS) and, when available, the Advanced Spaceborne Thermal Emission Radiometer (ASTER), both of which operate in the thermal infrared spectrum. OMI and MODIS offer daily coverage of the Earth’s surface but preliminary results indicate that most of the SO2 emissions at persistently active explosive volcanoes (e.g. Semeru, Santiaguito, Sakurajima) are not detectable by these instruments, mostly due to their low spatial resolution. Only the strongest explosions produce plumes large enough to be detected by satellite instruments and even then, their signal is difficult to separate from ambient noise in the data. Some volcanoes that exhibit less frequent but more intense explosive activity (e.g. Soufrière Hills volcano) produce plumes that are clearly identifiable, but their background activity remains inconspicuous. ASTER’s higher spatial resolution theoretically provides a better means to detect small plumes. However its limited spectral resolution and more importantly, the 16-day return period, make it impossible to accurately quantify representative fluxes. Our study demonstrates the difficulty in estimating SO2 fluxes from persistently active explosive volcanoes from satellite data alone, and underlies the need for comprehensive and continuous ground-based measurements at this type of volcanoes.

Smekens, J.; Clarke, A. B.

2010-12-01

419

Regional climate responses to geoengineering with tropical and Arctic SO2 injections  

NASA Astrophysics Data System (ADS)

Anthropogenic stratospheric aerosol production, so as to reduce solar insolation and cool Earth, has been suggested as an emergency response to geoengineer the planet in response to global warming. While volcanic eruptions have been suggested as innocuous examples of stratospheric aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone depletion and regional hydrologic and temperature responses. To further investigate the climate response, here we simulate the climate response to both tropical and Arctic stratospheric injection of sulfate aerosol precursors using a comprehensive atmosphere-ocean general circulation model, the National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE. We inject SO2 and the model converts it to sulfate aerosols, transports the aerosols and removes them through dry and wet deposition, and calculates the climate response to the radiative forcing from the aerosols. We conduct simulations of future climate with the Intergovernmental Panel on Climate Change A1B business-as-usual scenario both with and without geoengineering and compare the results. We find that if there were a way to continuously inject SO2 into the lower stratosphere, it would produce global cooling. Tropical SO2 injection would produce sustained cooling over most of the world, with more cooling over continents. Arctic SO2 injection would not just cool the Arctic. Both tropical and Arctic SO2 injection would disrupt the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people. These regional climate anomalies are but one of many reasons that argue against the implementation of this kind of geoengineering.

Robock, Alan; Oman, Luke; Stenchikov, Georgiy L.

2008-08-01

420

Improvement in the Selectivity of Semiconducting Resistive-type NO2 Sensors Linked with Calorimetric Hydrocarbon Sensors  

NASA Astrophysics Data System (ADS)

Improvement in the selectivity of semiconducting resistive-type NO2 sensors has been achieved by numerical compensation derived from the output of calorimetric hydrocarbon sensors. The electrical resistance of resistive-type sensors using thick-film SnO2 increases due to exposure to NO2, whereas its resistance is decreased by i-C4H10. Oxidizing gases such as O2 and NO2 which are electronegative are adsorbed on the surface of n-type semiconductors, whereas reducing gases such as hydrocarbons and carbon monoxide react with these adsorbed oxidizing gases, causing electrons to return to the semiconductor. Calorimetric sensors are based on the principle of catalytic combustion between reducing gases and atmospheric oxygen on the surface of gas-detecting materials, therefore they are sensitive to reducing gases such as hydrocarbons, but are insensitive to oxidizing gases. It was found that the resistance of NO2 sensors in the range from 0 to 100 ppm NO2 was unaffected by the co-existence of 0 to 300 ppm i-C4H10 using a semiconducting NO2 sensor, a calorimetric sensor and numerical compensation.

Yamada, Yasushi; Ogita, Masami

2002-09-01

421

40 CFR 52.1923 - Best Available Retrofit Requirements (BART) for SO2 and Interstate pollutant transport provisions...  

Code of Federal Regulations, 2014 CFR

...SO2 and Interstate pollutant transport provisions; What are the...PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL...SO2 and Interstate pollutant transport provisions; What are the...a.m. and 12 midnight. Air pollution control...

2014-07-01

422

Extending the long-term record of volcanic SO2 emissions with the Ozone Mapping and Profiler Suite nadir mapper  

NASA Astrophysics Data System (ADS)

Uninterrupted, global space-based monitoring of volcanic sulfur dioxide (SO2) emissions is critical for climate modeling and aviation hazard mitigation. We report the first volcanic SO2 measurements using ultraviolet (UV) Ozone Mapping and Profiler Suite (OMPS) nadir mapper data. OMPS was launched on the Suomi National Polar-orbiting Partnership satellite in October 2011. We demonstrate the sensitivity of OMPS SO2 measurements by quantifying SO2 emissions from the modest eruption of Paluweh volcano (Indonesia) in February 2013 and tracking the dispersion of the volcanic SO2 cloud. The OMPS SO2 retrievals are validated using Ozone Monitoring Instrument and Atmospheric Infrared Sounder measurements. The results confirm the ability of OMPS to extend the long-term record of volcanic SO2 emissions based on UV satellite observations. We also show that the Paluweh volcanic SO2 reached the lower stratosphere, further demonstrating the impact of small tropical volcanic eruptions on stratospheric aerosol optical depth and climate.

Carn, S. A.; Yang, K.; Prata, A. J.; Krotkov, N. A.

2015-02-01

423

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, Hg, and flow rate.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Standard missing data procedures for SO2, NOX, Hg, and flow... CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2 , NOX , Hg, and...

2010-07-01

424

Photoenhanced NO2 loss on simulated urban grime  

NASA Astrophysics Data System (ADS)

Solid and liquid particles provide surfaces for heterogeneous reaction, influencing the abundance and distribution of trace gases affecting air quality in urban environments. However, condensed matter can even be found on films coating urban surfaces (such as roads and buildings), also called “urban grime”. The present study focuses on the heterogeneous reaction between gaseous NO2 and solid films used as a proxy of “urban grime”. These reactions were investigated under simulated atmospheric conditions with respect to relative humidity, NO2 concentration and irradiation using a coated wall flow tube reactor. This proxy was tested by the mixture of organic compounds (pyrene), inorganic compounds (potassium nitrate) and Metals (iron oxide). The geometric steady-state uptake coefficients (?geo) obtained when pyrene/KNO3 films are exposed to 50 ppbv of NO2 ranged from 1.12×10-7 in the dark to 2.67×10-6 under near-UV irradiation (300-420 nm) and decreased with increasing NO2 concentration in the range 30-120 ppbv. The NO2 removal is linearly dependent on the light intensity with release of gas-phase NO and HONO, which rapidly photodissociates to form OH in the troposphere. The analysis of this film by IC and GC-MS showed the formation of nitrite ion and traces of 1-nitropyrene. A light-induced reaction mechanism is proposed for this system. The results discussed here suggest that urban “grime” on windows and buildings containing PAHs may be a key player in urban air pollution. The presence of iron oxide in the film is currently being treated in order to know its effect and reactivity towards organic compounds and gas-phase NO2 under irradiation and to see how can real urban film surfaces be photoenhanced in the presence of gas-phase NO2.

Ammar, R.; Monge, M. E.; D'Anna, B.; George, C.

2010-12-01

425

CCI2 reactions with HCI, NO2 and O2  

NASA Astrophysics Data System (ADS)

The IR Multiphoton Dissociation (IRMPD) of CDCl3 different gases was studied with the flash photolysis technique using a tunable CO2 TEA laser tuned to the 10P(48) line. CDCl3 samples were irradiated in the presence of HCl to analyze a possible recombination of the primary dissociation fragments CCl2 and DCl. The IRMPD of CDCl3 was also studied in mixtures of HCl/Ar, O2/Ar and NO2/Ar. In the experiences with added HCl, CHCl3 was obtained as major product evidencing the existence of the CCl2 and DCl recombination reaction. The dissociation probabilities per pulse obtained with the addition of different gases were compared.

Freytes, V. M.; Codnia, J.; Azcarate, M. L.

2004-10-01

426

Sulfur dioxide (SO2) from MIPAS in the upper troposphere and lower stratosphere 2002-2012  

NASA Astrophysics Data System (ADS)

Vertically resolved distributions of sulfur dioxide (SO2) with global coverage in the height region from the upper troposphere to ~ 20 km altitude have been derived from observations by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat for the period July 2002 to April 2012. Retrieved volume mixing ratio profiles representing single measurements are characterized by typical errors in the range of 70-100 pptv and by a vertical resolution ranging from 3-5 km. Comparison with ACE-FTS observations revealed a slightly varying bias with altitude of -20 to 50 pptv for the MIPAS dataset in case of volcanically enhanced concentrations. For background concentrations the comparison showed a systematic difference between the two major MIPAS observation periods. After debiasing, the difference could be reduced to biases within -10 to 20 pptv in the altitude range of 10-20 km with respect to ACE-FTS. Further comparisons of the debiased MIPAS dataset with in-situ measurements from various aircraft campaigns showed no obvious inconsistencies within a range of around ±50 pptv. The SO2 emissions of more than thirty volcanic eruptions could be identified in the upper troposphere and lower stratosphere (UTLS). Emitted SO2 masses and lifetimes within different altitude ranges in the UTLS have been derived for a large part of these eruptions. Masses are in most cases within estimations derived from other instruments. From three of the major eruptions within the MIPAS measurement period - Kasatochi in August 2008, Sarychev in June 2009 and Nabro in June 2011 - derived lifetimes of SO2 for the altitude ranges 10-14, 14-18, and 18-22 km are 13.3±2.1, 23.6±1.2, and 32.3±5.5 d, respectively. By omitting periods with obvious volcanic influence we have derived background mixing ratio distributions of SO2. At 10 km altitude these indicate an annual cycle at northern mid- and high latitudes with maximum values in summer and an amplitude of about 30 pptv. At higher altitudes of about 16-18 km enhanced mixing ratios of SO2 can be found in the region of the Asian and the North-American monsoon in summer - a possible connection to an aerosol layer discovered by Vernier et al. (2011b) in that region.

Höpfner, M.; Boone, C. D.; Funke, B.; Glatthor, N.; Grabowski, U.; Günther, A.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; Pumphrey, H. C.; Read, W. G.; Roiger, A.; Stiller, G.; Schlager, H.; von Clarmann, T.; Wissmüller, K.

2015-02-01

427

East Asian SO2 pollution plume over Europe - Part 2: Evolution and potential impact  

NASA Astrophysics Data System (ADS)

We report on the first observation-based case study of an aged East Asian anthropogenic SO2 pollution plume over Europe. Our airborne measurements in that plume detected highly elevated SO2 mole fractions (up to 900 pmol/mol) between about 5000 and 7000 m altitude. Here, we focus on investigations of the origin, dispersion, evolution, conversion, and potential impact of the observed excess SO2. In particular, we investigate SO2 conversion to gas-phase sulfuric acid and sulfuric acid aerosols. Our FLEXPART and LAGRANTO model simulations, along with additional trace gas measurements, suggest that the plume originated from East Asian fossil fuel combustion sources and, 8-7 days prior to its arrival over Europe, ascended over the coast region of central East Asia to 9000 m altitude, probably in a cyclonic system with an associated warm conveyor belt. During this initial plume ascent a substantial fraction of the initially available SO2 must have escaped from removal by cloud processes. Hereafter, while mostly descending slowly, the plume experienced advection across the North Pacific, North America and the North Atlantic. During its upper troposphere travel, clouds were absent in and above the plume and OH-induced gas-phase conversion of SO2 to gas-phase sulfuric acid (GSA) was operative, followed by GSA nucleation and condensation leading to sulfuric acid aerosol formation and growth. Our AEROFOR model simulations indicate that numerous large sulfuric acid aerosol particles were formed, which at least temporarily, caused substantial horizontal visibility degradation, and which have the potential to act as water vapor condensation nuclei in liquid water cloud formation, already at water vapor supersaturations as low as about 0.1%. Our AEROFOR model simulations also indicate that those fossil fuel combustion generated soot particles, which have survived cloud induced removal during the initial plume ascent, have experienced extensive H2SO4/H2O-coating, during upper troposphere plume travel. This coating may have dramatically altered the morphology and markedly increased the light absorption efficiency of soot particles.

Fiedler, V.; Arnold, F.; Schlager, H.; Dörnbrack, A.; Pirjola, L.; Stohl, A.

2009-07-01

428

Electrical breakdown of gases  

Microsoft Academic Search

A collection of individual works on electrical discharges is presented. Topics covered include: fundamental processes in the electrical breakdown of gases; vacuum breakdown; spark breakdown in uniform fields; corona discharge; spark breakdown in non-uniform fields; breakdown voltage characteristics; irradiation and time lags; high-frequency breakdown of gases; laser-induced electrical breakdown of gases; spark channels; and electrode phenomena. (GHT)

J. M. Meek; J. D. Craggs

1978-01-01

429

SO2-rock interaction on Io - Reaction under highly oxidizing conditions  

NASA Technical Reports Server (NTRS)

Laboratory simulations are used here to test the possibility that interactions of SO2 and silicates can produce Na-S compounds which can account for the observed surface enrichment of Na relative to Si on Io. It is concluded that there are three viable hypotheses for the nature and origin of the Na compounds on the surface of Io: (1) Na2SO4 from SO2-silicate interactions, (2) Na-sulfides from elemental S, silicate interactions, and (3) directly erupted volcanic Na. The present studies indicate the elemental Si is not required to form Na compounds in crustal igneous interactions. Thus, the presence of Na compounds provides no constraint on elemental S but igneous formation of Na-S compounds is not tied to models of Io which contain elemental S.

Johnson, M. L.; Burnett, D. S.

1993-01-01

430

Two-photon dissociation of SO 2 in the ultraviolet region  

NASA Astrophysics Data System (ADS)

Two-photon photodissociation of SO 2 through the overlineB1B 1 state at 286-309 nm has been studied by a perfect focusing mass spectroscopy and a photofragment imaging technique. Sulfur atoms were detected as photofragments by a resonance-enhanced multiphoton ionization technique. The lower limits of the anisotropy parameters for angular distributions are 0.42 ± 0.06 for S( 1D) and 0.50 ± 0.05 for S( 3P). The velocity distributions of the S( 1D and 3P) photofragments are analyzed assuming dissociation pathways: SO 2 + 2 ???S( 1D and 3P) + O 2(a 1? and X 3? -g). The two-photon excite the 8 eV region is assigned to be overlineB1B 1 with C 2v symmetry.

Sato, Tetsuya; Kinugawa, Tohru; Arikawa, Tatsuo; Kawasaki, Masahiro

1992-09-01

431

Influence of Tropospheric SO2 Emissions on Particle Formation and the Stratospheric Humidity  

NASA Technical Reports Server (NTRS)

Stratospheric water vapor plays an important role in the chemistry and radiation budget of the stratosphere. Throughout the last decades stratospheric water vapor levels have increased and several processes have been suggested to contribute to this trend. Here we present a mechanism that would link increasing anthropogenic SO2 emissions in southern and eastern Asia with an increase in stratospheric water. Trajectory studies and model simulations suggest that the SO2 increase results in the formation of more sulfuric acid aerosol particles in the upper tropical troposphere. As a consequence, more ice crystals of smaller size are formed in the tropical tropopause, which are lifted into the stratosphere more readily. Our model calculations suggest that such a mechanism could increase the amount of water that entered the stratosphere in the condensed phase by up to 0.5 ppmv from 1950-2000.

Notholt, J.; Luo, B. P.; Fueglistaler, S.; Weisenstein, D.; Rex, M.; Lawrence, M. G.; Bingemer, H.; Wohltmann, I.; Corti, T.; Warneke, T.; vonKuhlmann, R.; Peters, T.

2005-01-01

432

Lifetime assessment analysis of Galileo Li/SO2 cells: Final report  

SciTech Connect

Galileo Li/SO2 cells from five lots and five storage temperatures were studied to establish a database from which the performance of flight modules may be predicted. Nondestructive tests consisting of complex impedance analysis and a 15-s pulse were performed on all cells. Chemical analysis was performed on one cell from each lot/storage group, and the remaining cells were discharged at Galileo mission loads. An additional number of cells were placed on high-temperature accelerated aging storage for 6 months and then discharged. All data were statistically analyzed. Results indicate that the present Galileo design Li/SO2 cell will satisfy electrical requirements for a 10-year mission. 10 figs., 4 tabs.

Levy, S.C.; Jaeger, C.D.; Bouchard, D.A.

1988-12-01

433

Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: A feasible aviation safety measure to prevent potential encounters with volcanic plumes  

USGS Publications Warehouse

Volcanic ash constitutes a risk to aviation, mainly due to its ability tocause jet engines to fail. Other risks include the possibility of abrasion ofwindshields and potentially serious damage to avionic systems. These hazardshave been widely recognized since the early 1980s, when volcanic ash provokedseveral incidents of engine failure in commercial aircraft. In addition tovolcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulativeexposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4)aerosols potentially affects e.g. windows, air frame and may cause permanentdamage to engines. SO2 receives most attention among the gas speciescommonly found in volcanic plumes because its presence above the lowertroposphere is a clear proxy for a volcanic cloud and indicates that fine ashcould also be present. Up to now, remote sensing of SO2 via Differential Optical AbsorptionSpectroscopy (DOAS) in the ultraviolet spectral region has been used tomeasure volcanic clouds from ground based, airborne and satellite platforms.Attention has been given to volcanic emission strength, chemistry insidevolcanic clouds and measurement procedures were adapted accordingly. Here wepresent a set of experimental and model results, highlighting the feasibilityof DOAS to be used as an airborne early detection system of SO2 intwo spatial dimensions. In order to prove our new concept, simultaneousairborne and ground-based measurements of the plume of Popocat??petlvolcano, Mexico, were conducted in April 2010. The plume extended at analtitude around 5250 m above sea level and was approached and traversed at thesame altitude with several forward looking DOAS systems aboard an airplane.These DOAS systems measured SO2 in the flight direction and at?? 40 mrad (2.3??) angles relative to it in both, horizontal andvertical directions. The approaches started at up to 25 km distance to theplume and SO2 was measured at all times well above the detectionlimit. In combination with radiative transfer studies, this study indicatesthat an extended volcanic cloud with a concentration of 1012 molecules cm-3 at typical flight levels of 10 km can be detectedunambiguously at distances of up to 80 km away. This range provides enoughtime (approx. 5 min) for pilots to take action to avoid entering avolcanic cloud in the flight path, suggesting that this technique can be usedas an effective aid to prevent dangerous aircraft encounters with potentiallyash rich volcanic clouds. ?? Author(s) 2011.

Vogel, L.; Galle, B.; Kern, C.; Delgado, Granados H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lubcke, P.; Alvarez, Nieves J.M.; Cardenas, Gonzales L.; Platt, U.

2011-01-01

434

Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes  

NASA Astrophysics Data System (ADS)

Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ± 40 mrad (2.3°) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the detection limit. In combination with radiative transfer studies, this study indicates that an extended volcanic cloud with a concentration of 1012 molecules cm-3 at typical flight levels of 10 km can be detected unambiguously at distances of up to 80 km away. This range provides enough time (approx. 5 min) for pilots to take action to avoid entering a volcanic cloud in the flight path, suggesting that this technique can be used as an effective aid to prevent dangerous aircraft encounters with potentially ash rich volcanic clouds.

Vogel, L.; Galle, B.; Kern, C.; Delgado Granados, H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lübcke, P.; Alvarez Nieves, J. M.; Cárdenas Gonzáles, L.; Platt, U.

2011-05-01

435

Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes  

NASA Astrophysics Data System (ADS)

Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3°) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the detection limit. In combination with radiative transfer studies, this study indicates that an extended volcanic cloud with a concentration of 1012 molecules cm-3 at typical flight levels of 10 km can be detected unambiguously at distances of up to 80 km away. This range provides enough time (approx. 5 min) for pilots to take action to avoid entering a volcanic cloud in the flight path, suggesting that this technique can be used as an effective aid to prevent dangerous aircraft encounters with potentially ash rich volcanic clouds.

Vogel, L.; Galle, B.; Kern, C.; Delgado Granados, H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lübcke, P.; Alvarez Nieves, J. M.; Cárdenas Gonzáles, L.; Platt, U.

2011-09-01

436

RATE CONTROLLING PROCESSES AND ENHANCEMENT STRATEGIES IN HUMIDIFICATION FOR DUCT SO2 CAPTURE  

EPA Science Inventory

The report gives results of an investigation of the fundamental rate processes that govern sulfur capture in power plant ducts during humidification of flue gases. The specific application was the reactivation of partially sulfated calcium-based sorbents from in-furnace injection...

437

Removal of SO2 using a wet-type nonthermal plasma reactor  

Microsoft Academic Search

Wet-plasma process for SO2 removal has been proposed, and fundamental characteristics have been evaluated. The plasma reactor was a wire-cylinder wet type ESP that was driven by pulsed high voltage. Water film containing ammonium peroxodisulfate ((NH4)2 S2O8) was maintained on the wall of the reactor. By raising the temperature of the solution up to 80°C, ammonium ion (NH4+) and hydrogen

Youhei Kinoshita; Keita Saito; Kazunori Takashima; Shinji Katsura; Akira Mizuno

2001-01-01

438

Integrated assessment of CO 2 and SO 2 policies in North East Asia  

Microsoft Academic Search

This study quantifies the costs and impacts of six scenarios for carbon dioxide (CO2) and sulphur dioxide (SO2) emissions in North East Asia (NEA) within an integrated probabilistic analysis. The inclusion of the cooling effect of sulphates means that CO2 control in China would be likely to increase the regional temperature in NEA in the short-term. This is because CO2

Yeora Chae; Chris Hope

2003-01-01

439

Combustion and SO 2?NO x emissions of bituminous coal particles treated with calcium magnesium acetate  

Microsoft Academic Search

Experiments were conducted in an externally heated drop-tube furnace to assess the effectiveness of the chemical calcium magnesium acetate [CMA, CaMg2(CH3COO)6] as a combustion catalyst and a coal pretreatment agent for reducing SO2 emissions. Bituminous coal particles of two distinct sizes, pulverized (75–90 ?m) or micronized and beneficiated (mean diameter ?3.5 ?m) were burned. To measure the coal particle temperatures

Ajay Atal; Judi Steciak; Yiannis A. Levendis

1995-01-01

440

Mapping SO 2 Frost on Io by the Modeling of NIMS Hyperspectral Images  

Microsoft Academic Search

We analyze a collection of hyperspectral images of Io acquired by the near infrared mapping spectrometer (NIMS) of Galileo during the G2 to E16 orbits of Jupiter. This analysis leads to the geographical distribution and physical characterization of SO2 frost deposits over about three-fourths of Io's surface. These deposits are excellent tracers of various phenomena, including volcanic production and emission,

Sylvain Douté; Bernard Schmitt; Rosaly Lopes-Gautier; Robert Carlson; Laurence Soderblom; James Shirley

2001-01-01